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Sample records for imipenem

  1. Insertion sequence transposition determines imipenem resistance in Acinetobacter baumannii.

    PubMed

    Kuo, Han-Yueh; Chang, Kai-Chih; Liu, Chih-Chin; Tang, Chuan Yi; Peng, Jhih-Hua; Lu, Chia-Wei; Tu, Chi-Chao; Liou, Ming-Li

    2014-10-01

    This study employed genomewide analysis to investigate potential resistance mechanisms in Acinetobacter baumannii following imipenem exposure. Imipenem-selected mutants were generated from the imipenem-susceptible strain ATCC 17978 by multistep selection resistance. Antibiotic susceptibilities were examined, and the selected mutants originated from the ATCC 17978 strain were confirmed by pulsed-field gel electrophoresis. The genomic sequence of a resistant mutant was analyzed using a next-generation sequencing platform, and genetic recombination was further confirmed by PCR. The result showed that phenotypic resistance was observed with carbapenem upon exposure to various concentrations of imipenem. Genomewide analysis showed that ISAba1 transposition was initiated by imipenem exposure at concentrations up to 0.5 mg/L. Transposition of ISAba1 upstream of blaOXA-95 was detected in all the selected mutants. The expression of blaOXA-95 was further analyzed by quantitative PCR, and the results demonstrated that a 200-fold increase in gene expression was required for resistance to imipenem. This study concluded that imipenem exposure at a concentration of 0.5 mg/L mediated the transposition of ISAba1 upstream of the blaOXA-95 gene and resulted in the overexpression of blaOXA-95 gene, which may play a major role in the resistance to imipenem in A. baumannii.

  2. Imipenem: a potent inducer of multidrug resistance in Acinetobacter baumannii.

    PubMed

    Kuo, Han-Yueh; Chang, Kai-Chih; Kuo, Jai-Wei; Yueh, Hui-Wen; Liou, Ming-Li

    2012-01-01

    This study investigated the progression of multidrug resistance upon exposure to imipenem in Acinetobacter baumannii. Eighteen A. baumannii strains, including two reference strains (ATCC 19606 and ATCC 17978), four clinical strains (AB56, AB242, AB273 and AB279) and 12 antibiotic-selected mutant strains, were used in this study. Imipenem-selected mutants were generated from imipenem-susceptible strains (ATCC 19606, ATCC 17978 and AB242) by multistep selection resistance. Amikacin-, ciprofloxacin-, colistin-, meropenem- and ceftazidime-selected mutants were also generated from the two reference strains and were used for comparison. Antibiotic susceptibilities in the absence and presence of the efflux pump inhibitors carbonyl cyanide m-chlorophenylhydrazone (CCCP) and 1-(1-naphthylmethyl)-piperazine (NMP) were examined in the three imipenem-selected mutants and the three clinical multidrug-resistant (MDR) isolates. Expression profiles of the antimicrobial resistance genes in the imipenem-selected mutants and their parental strains were also determined. The results showed that imipenem was more likely, compared with the other antibiotics, to induce a MDR phenotype in the two reference strains. Differences in OXA-51-like carbapenemase, efflux pumps or/and AmpC β-lactamase expression were observed in the three imipenem-selected mutants. Moreover, a reduction in imipenem or amikacin resistance was observed when the imipenem-selected mutants and clinical isolates were exposed to NMP and CCCP. This study concluded that imipenem might be a potent inducer of multidrug resistance in A. baumannii strains. OXA-51-like carbapenemase combined with other resistance mechanisms may contribute to the development of multidrug resistance in A. baumannii. Monitoring the use of carbapenems is required to reduce the spread of MDR A. baumannii in hospitals.

  3. Prospective determination of plasma imipenem concentrations in critically ill children.

    PubMed

    Giannoni, Eric; Moreillon, Philippe; Cotting, Jacques; Moessinger, Adrien; Bille, Jacques; Décosterd, Laurent; Zanetti, Giorgio; Majcherczyk, Paul; Bugnon, Denis

    2006-07-01

    Plasma imipenem concentrations were measured in 19 critically ill children (median age, 0.8 year; range, 0.02 to 12.9 years). Wide interindividual variations (2 to 4x at peak and >10x at trough concentrations) resulted in unpredictable plasma levels in several children. To avoid subtherapeutic drug levels, we recommend treatment with at least 100 mg/kg of body weight/day of imipenem-cilastatin for critically ill children requiring such therapy.

  4. Prospective Determination of Plasma Imipenem Concentrations in Critically Ill Children

    PubMed Central

    Giannoni, Eric; Moreillon, Philippe; Cotting, Jacques; Moessinger, Adrien; Bille, Jacques; Décosterd, Laurent; Zanetti, Giorgio; Majcherczyk, Paul; Bugnon, Denis

    2006-01-01

    Plasma imipenem concentrations were measured in 19 critically ill children (median age, 0.8 year; range, 0.02 to 12.9 years). Wide interindividual variations (2 to 4× at peak and >10× at trough concentrations) resulted in unpredictable plasma levels in several children. To avoid subtherapeutic drug levels, we recommend treatment with at least 100 mg/kg of body weight/day of imipenem-cilastatin for critically ill children requiring such therapy. PMID:16801447

  5. Imipenem antagonism of the in vitro activity of piperacillin against Pseudomonas aeruginosa.

    PubMed Central

    Bertram, M A; Young, L S

    1984-01-01

    The MICs of imipenem and piperacillin, alone and in combination, against Pseudomonas aeruginosa were determined in a checkerboard titration microdilution assay. A dramatic, one-way antagonism of imipenem for piperacillin was demonstrated in 28 of the 35 strains examined; antagonism was associated with the induction of a beta-lactamase. PMID:6435517

  6. Liquid chromatographic method for the simultaneous determination of imipenem and sulbactam in mouse plasma.

    PubMed

    Aparicio, Irene; Bello, Miguel Angel; Callejón, Manuel; Jiménez, Juan Carlos

    2006-10-01

    The first analytical method is developed and validated for the simultaneous determination of imipenem and sulbactam in mouse plasma. Sample treatment is based on plasma stabilization with 4-(2-hydroxyethyl)piperazine-ethanesulfonic acid (HEPES) (0.5 mol/L; pH 7.0)-water-ethylene glycol (2:1:1, v/v/v), precipitation of plasma proteins with acetonitrile, centrifugation, evaporation, and reconstitution with borate buffer. Analytical determination is carried out by high-performance liquid chromatography with diode-array detection. Chromatographic separation is achieved within 11 min on a C(18) column by gradient elution with borate buffer (0.1 mol/L, pH 7.2) and methanol. Imipenem and sulbactam are monitored at 295 and 230 nm, respectively. The overall interday accuracy is in the range of 95% to 100% and from 98% and 101% for imipenem and sulbactam, respectively. Interday precision is below 8% and 4% for imipenem and sulbactam, respectively. Limits of quantitation of imipenem and sulbactam are 0.05 and 1.0 microg/mL, respectively. The mean extraction recoveries are 94.5% and 94.2% for imipenem and sulbactam, respectively. The described method allows an accurate, simple, and rapid identification and quantitation of imipenem and sulbactam in mouse plasma. This method is applied to the analysis of imipenem and sulbactam in mouse plasma after drug administration.

  7. Activity of Imipenem against Klebsiella pneumoniae Biofilms In Vitro and In Vivo

    PubMed Central

    Chen, Ping; Seth, Akhil K.; Abercrombie, Johnathan J.; Mustoe, Thomas A.

    2014-01-01

    Encapsulated Klebsiella pneumoniae has emerged as one of the most clinically relevant and more frequently encountered opportunistic pathogens in combat wounds as the result of nosocomial infection. In this report, we show that imipenem displayed potent activity against established K. pneumoniae biofilms under both static and flow conditions in vitro. Using a rabbit ear model, we also demonstrated that imipenem was highly effective against preformed K. pneumoniae biofilms in wounds. PMID:24247132

  8. Is continuous infusion of imipenem always the best choice?

    PubMed

    Suchánková, Hana; Lipš, Michal; Urbánek, Karel; Neely, Michael N; Strojil, Jan

    2017-03-01

    Monte Carlo simulations allow prediction and comparison of concentration-time profiles arising from different dosing regimens in a defined population, provided a population pharmacokinetic model has been established. The aims of this study were to evaluate the population pharmacokinetics of imipenem in critically ill patients with hospital-acquired pneumonia (HAP) and to assess the probability of target attainment (PTA) and cumulative fraction of response (CFR) using EUCAST data. A two-compartment model based on a data set of 19 subjects was employed. Various dosage regimens at 0.5-h and 3-h infusion rates and as continuous infusion were evaluated against the pharmacodynamic targets of 20%fT>MIC, 40%fT>MIC and 100%fT>MIC. For the target of 40%fT>MIC, all 0.5-h infusion regimens achieved optimal exposures (CFR ≥ 90%) against Escherichia coli and Staphylococcus aureus, with nearly optimal exposure against Klebsiella pneumoniae (CFR ≥ 89.4%). The 3-h infusions and continuous infusion exceeded 97% CFR against all pathogens with the exception of Pseudomonas aeruginosa and Acinetobacter spp., where the maximum CFRs were 85.5% and 88.4%, respectively. For the 100%fT>MIC target, only continuous infusion was associated with nearly optimal exposures. Higher PTAs for the targets of 40%fT>MIC and 100%fT>MIC were achieved with 3-h infusions and continuous infusion in comparison with 0.5-h infusions; however, continuous infusion carries a risk of not reaching the MIC of less susceptible pathogens in a higher proportion of patients. In critically ill patients with HAP with risk factors for Gram-negative non-fermenting bacteria, maximum doses administered as extended infusions may be necessary.

  9. Piperacillin-tazobactam versus imipenem-cilastatin for treatment of intra-abdominal infections.

    PubMed Central

    Brismar, B; Malmborg, A S; Tunevall, G; Wretlind, B; Bergman, L; Mentzing, L O; Nyström, P O; Kihlström, E; Bäckstrand, B; Skau, T

    1992-01-01

    In order to compare the clinical and microbiological efficacies and safety of piperacillin plus tazobactam with those of imipenem plus cilastatin, 134 patients with intra-abdominal infections (73 patients with appendicitis) participated in an open randomized comparative multicenter trial. A total of 40 men and 29 women (mean age, 53 years; age range, 18 to 92 years) were enrolled in the piperacillin-tazobactam group and 40 men and 25 women (mean age, 54 years; age range, 16 to 91 years) were enrolled in the imipenem-cilastatin group. The patients received either piperacillin (4 g) and tazobactam (500 mg) every 8 h or imipenem and cilastatin (500 mg each) every 8 h. Both regimens were given by intravenous infusion. A total of 113 patients were clinically evaluable. Of 55 patients who received piperacillin-tazobactam, 50 were clinically cured, while 40 of 58 patients in the imipenem-cilastatin group were clinically cured. The differences were significant (Wilcoxon test; P = 0.005). There were 4 failures or relapses in the piperacillin-tazobactam group and 18 failures or relapses in the imipenem-cilastatin group. The microorganisms isolated were eradicated in similar proportions in the two patient groups. Adverse reactions, mainly gastrointestinal disturbances and nausea, were noted in 13 patients who received piperacillin-tazobactam and in 14 patients who received imipenem-cilastatin. Results of the present study show that piperacillin-tazobactam is effective and safe for the treatment of intra-abdominal infections. PMID:1336347

  10. Activity of imipenem against VIM-1 metallo-beta-lactamase-producing Klebsiella pneumoniae in the murine thigh infection model.

    PubMed

    Daikos, G L; Panagiotakopoulou, A; Tzelepi, E; Loli, A; Tzouvelekis, L S; Miriagou, V

    2007-02-01

    The in-vivo activity of imipenem against VIM-1-producing Klebsiella pneumoniae (VPKP) was assessed in a thigh infection model in neutropenic mice. Animals were infected with three VPKP isolates (imipenem MICs 2, 4 and 32 mg/L, respectively) and a susceptible clinical isolate (MIC 0.125 mg/L) that did not produce any beta-lactamase with broad-spectrum activity. Bacterial density at the site of infection was determined after imipenem treatment (30 and 60 mg/kg every 2 h for 24 h). The log(10) reduction in CFU/thigh was greatest for the wild-type isolate, intermediate for the two imipenem-susceptible VPKP isolates, and lowest for the imipenem-resistant VPKP isolate. Whilst in-vivo imipenem activity appeared reduced against in-vitro susceptible VIM-1 producers compared with a VIM-1-negative control, an increased drug dosage could moderate this reduction.

  11. Antimicrobial Resistance of Acinetobacter baumannii to Imipenem in Iran: A Systematic Review and Meta-Analysis.

    PubMed

    Pourhajibagher, Maryam; Hashemi, Farhad B; Pourakbari, Babak; Aziemzadeh, Masoud; Bahador, Abbas

    2016-01-01

    Imipenem-resistant multi-drug resistant (IR-MDR) Acinetobacter baumannii has been emerged as a morbidity successful nosocomial pathogen throughout the world.To address imipenem being yet the most effective antimicrobial agent against A. baumannii to control outbreaks and treat patients, a systematic review and meta-analysis was performed to evaluate the prevalence of IR-MDR A. baumannii. We systematically searched Web of Science, PubMed, MEDLINE, Science Direct, EMBASE, Scopus, Cochrane Library, Google Scholar, and Iranian databases to identify studies addressing the antibiotic resistance of A. baumannii to imipenem and the frequency of MDR strains in Iran. Out of 58 articles and after a secondary screening using inclusion and exclusion criteria and on the basis of title and abstract evaluation, 51 studies were selected for analysis. The meta-analysis revealed that 55% [95% confidence interval (CI), 53.0-56.5] of A. baumannii were resistant to imipenem and 74% (95% CI, 61.3-83.9) were MDR. The MDR A. baumannii population in Iran is rapidly changing toward a growing resistance to imipenem. Our findings highlight the critical need for a comprehensive monitoring and infection control policy as well as a national susceptibility review program that evaluates IR-MDR A. baumannii isolates from various parts of Iran.

  12. Comparison of imipenem and meropenem antibiotics for the MALDI-TOF MS detection of carbapenemase activity.

    PubMed

    Rotova, Veronika; Papagiannitsis, Costas C; Skalova, Anna; Chudejova, Katerina; Hrabak, Jaroslav

    2017-04-05

    A comparison of carbapenem molecules for the detection of carbapenemase-producing bacteria by MALDI-TOF MS showed that imipenem exhibited higher sensitivity (97%) and specificity (100%) scores for Pseudomonas aeruginosa than meropenem. However, meropenem was more efficient (98% sensitivity and 100% specificity) against Enterobacteriaceae.

  13. Imipenem disc for detection of KPC carbapenemase-producing Enterobacteriaceae in clinical practice.

    PubMed

    Benenson, Shmuel; Temper, Violeta; Cohen, Matan J; Schwartz, Carmela; Hidalgo-Grass, Carlos; Block, Colin

    2011-04-01

    The global spread of class A-carbapenemase-producing Enterobacteriaceae has made the development of a simple test a desirable goal. A disc diffusion test using imipenem was 100% sensitive and 96% specific in identifying carbapenemase-producing organisms, potentially reducing or eliminating the need for the relatively labor-intensive modified Hodge test.

  14. Resistant mechanisms and molecular epidemiology of imipenem-resistant Acinetobacter baumannii

    PubMed Central

    Xiao, Shu-Zhen; Chu, Hai-Qing; Han, Li-Zhong; Zhang, Zhe-Min; Li, Bing; Zhao, Lan; Xu, Liyun

    2016-01-01

    The aim of the study was to investigate the resistant mechanisms and homology of imipenem-resistant Acinetobacter baumannii (A. baumannii). A total of 46 non-duplicate imipenem-resistant A. baumannii clinical isolates were collected from three tertiary hospitals between July, 2011 and June, 2012. The minimal inhibitory concentrations (MICs) of antimicrobial agents were determined using the agar dilution method. Phenylalanine-arginine β-naphthylamide was used to detect the presence of the efflux pump-mediated resistant mechanism. Polymerase chain reaction was employed to amplify genes associated with drug resistance, including β-lactamase genes, efflux pump genes and outer membrane protein gene CarO. A few amplicons were randomly selected and sequenced. Multilocus sequence analysis (MLST) was employed in typing A. baumanni. A. baumannii was resistant to imipenem, simultaneously showing resistance to several other antimicrobials. In addition, 13 A. baumannii were found to mediate drug resistance through operation of the efflux pump. Of the various drug resistance genes tested, blaOXA-51 was present in 46 isolates, blaOXA-23 gene was present in 44 isolates and blaNDM gene was found in only one strain. Other drug resistant-associated genes, including blaKPC, blaIMP, blaOXA-24, blaOXA-58, blaSHV, blaGIM and blaVIM were not detected. Mutation of adeS and outer membrane protein gene CarO were found in a few of the imipenem-resistant isolates. The MLST analysis revealed that all 46 clinical isolates were clustered into 11 genotypes and the most frequent genotype was ST208. In conclusion, β-lactamase genes, genes involved in efflux pump and mutation of outer membrane protein encoding gene may be important in mediating imipenem resistance in A. baumannii. Of the 11 different genotypes, ST11 was shared by the majority of A. baumannii, which may be due to horizontal transfer of patients from hospitals. PMID:27485638

  15. In Vivo Pharmacokinetics/Pharmacodynamics of Colistin and Imipenem in Pseudomonas aeruginosa Biofilm Infection

    PubMed Central

    Wu, Hong; Ciofu, Oana; Song, Zhijun; Høiby, Niels

    2012-01-01

    Many Pseudomonas aeruginosa isolates from the airways of patients with cystic fibrosis (CF) are sensitive to antibiotics in susceptibility testing, but eradication of the infection is difficult. The main reason is the biofilm formation in the airways of patients with CF. The pharmacokinetics (PKs) and pharmacodynamics (PDs) of antimicrobials can reliably be used to predict whether antimicrobial regimens will achieve the maximum bactericidal effect against infections. Unfortunately, however, most PK/PD studies of antimicrobials have been done on planktonic cells and very few PK/PD studies have been done on biofilms, partly due to the lack of suitable models in vivo. In the present study, a biofilm lung infection model was developed to provide an objective and quantitative evaluation of the PK/PD profile of antimicrobials. Killing curves were set up to detect the antimicrobial kinetics on planktonic and biofilm P. aeruginosa cells in vivo. Colistin showed concentration-dependent killing, while imipenem showed time-dependent killing on both planktonic and biofilm P. aeruginosa cells in vivo. The parameter best correlated to the elimination of bacteria in lung by colistin was the area under the curve (AUC) versus MIC (AUC/MIC) for planktonic cells or the AUC versus minimal biofilm inhibitory concentration (MBIC; AUC/MBIC) for biofilm cells. The best-correlated parameter for imipenem was the time that the drug concentration was above the MIC for planktonic cells (TMIC) or time that the drug concentration was above the MBIC (TMBIC) for biofilm cells. However, the AUC/MIC of imipenem showed a better correlation with the efficacy of imipenem for biofilm infections (R2 = 0.89) than planktonic cell infections (R2 = 0.38). The postantibiotic effect (PAE) of colistin and imipenem was shorter in biofilm infections than planktonic cell infections in this model. PMID:22354300

  16. N-acetylcysteine selectively antagonizes the activity of imipenem in Pseudomonas aeruginosa by an OprD-mediated mechanism.

    PubMed

    Rodríguez-Beltrán, Jerónimo; Cabot, Gabriel; Valencia, Estela Ynés; Costas, Coloma; Bou, German; Oliver, Antonio; Blázquez, Jesús

    2015-01-01

    The modulating effect of N-acetylcysteine (NAC) on the activity of different antibiotics has been studied in Pseudomonas aeruginosa. Our results demonstrate that, in contrast to previous reports, only the activity of imipenem is clearly affected by NAC. MIC and checkerboard determinations indicate that the NAC-based modulation of imipenem activity is dependent mainly on OprD. SDS-PAGE of outer membrane proteins (OMPs) after NAC treatments demonstrates that NAC does not modify the expression of OprD, suggesting that NAC competitively inhibits the uptake of imipenem through OprD. Similar effects on imipenem activity were obtained with P. aeruginosa clinical isolates. Our results indicate that imipenem-susceptible P. aeruginosa strains become resistant upon simultaneous treatment with NAC and imipenem. Moreover, the generality of the observed effects of NAC on antibiotic activity was assessed with two additional bacterial species, Escherichia coli and Acinetobacter baumannii. Caution should be taken during treatments, as the activity of imipenem may be modified by physiologically attainable concentrations of NAC, particularly during intravenous and nebulized regimes.

  17. N-Acetylcysteine Selectively Antagonizes the Activity of Imipenem in Pseudomonas aeruginosa by an OprD-Mediated Mechanism

    PubMed Central

    Rodríguez-Beltrán, Jerónimo; Cabot, Gabriel; Valencia, Estela Ynés; Costas, Coloma; Bou, German; Oliver, Antonio

    2015-01-01

    The modulating effect of N-acetylcysteine (NAC) on the activity of different antibiotics has been studied in Pseudomonas aeruginosa. Our results demonstrate that, in contrast to previous reports, only the activity of imipenem is clearly affected by NAC. MIC and checkerboard determinations indicate that the NAC-based modulation of imipenem activity is dependent mainly on OprD. SDS-PAGE of outer membrane proteins (OMPs) after NAC treatments demonstrates that NAC does not modify the expression of OprD, suggesting that NAC competitively inhibits the uptake of imipenem through OprD. Similar effects on imipenem activity were obtained with P. aeruginosa clinical isolates. Our results indicate that imipenem-susceptible P. aeruginosa strains become resistant upon simultaneous treatment with NAC and imipenem. Moreover, the generality of the observed effects of NAC on antibiotic activity was assessed with two additional bacterial species, Escherichia coli and Acinetobacter baumannii. Caution should be taken during treatments, as the activity of imipenem may be modified by physiologically attainable concentrations of NAC, particularly during intravenous and nebulized regimes. PMID:25801561

  18. Emergence in Klebsiella pneumoniae of a Chromosome-Encoded SHV β-Lactamase That Compromises the Efficacy of Imipenem

    PubMed Central

    Poirel, Laurent; Héritier, Claire; Podglajen, Isabelle; Sougakoff, Wladimir; Gutmann, Laurent; Nordmann, Patrice

    2003-01-01

    A Klebsiella pneumoniae isolate was identified that had reduced susceptibility to several expanded-spectrum cephalosporins and imipenem. That isolate produced a chromosome-encoded SHV-type β-lactamase, SHV-38, that had an alanine to valine substitution in position Ambler 146 compared to β-lactamase SHV-1. The kinetic parameters for purified β-lactamases SHV-38 and SHV-1 showed that the hydrolytic spectrum of SHV-38 included only ceftazidime and imipenem. This report is the first example of an SHV-type β-lactamase capable of hydrolyzing imipenem. PMID:12543688

  19. ATR-FTIR spectroscopic investigation of imipenem-susceptible and -resistant Pseudomonas aeruginosa isogenic strains.

    PubMed

    Sockalingum, G D; Bouhedja, W; Pina, P; Allouch, P; Mandray, C; Labia, R; Millot, J M; Manfait, M

    1997-03-06

    The primary mechanism of imipenem resistance in Pseudomonas aeruginosa has been ascribed to an outer membrane impermeability owing to a loss of expression of protein D2. Attenuated total reflection-Fourier transform infrared spectroscopy in conjunction with statistical methods has been used as a new approach to rapidly discriminate four isogenic strains of P. aeruginosa--susceptible, less susceptible, and highly resistant to imipenem-- and to follow the structural modifications related to this low permeability. Decomposition of the broad protein and carbohydrate contours into underlying Gaussians and comparison of the susceptible and highly resistant strain provided quantitative and ultrastructural information on these strains. This methodology allows for discrimination not of the mutation itself but of its consequences observed in the protein and carbohydrate absorption regions. Its association with other existing biochemical methods may be envisaged since it may allow for rapid orientation of investigations in the field of bacterial resistance diagnosis.

  20. [Post-antibiotic effect of imipenem, amikacin and ciprofloxacin against various strains of Serratia marcescens].

    PubMed

    Bollet, C; Mallet, M N; Bouchemal, H; de Micco, P

    1990-05-01

    The authors compared the post-antibiotic effect (PAE) of imipenem, amikacin, ciprofloxacin, and latamoxef against Serratia marcescens ATCC 13880 (type strain) and against 12 clinical strains belonging to Grimont's most frequent biotypes: A2a, A3a, A3b, A4a, A4b, A5, A6a, A8a, A8b, A8c, TT, TCT. PAE was determined by measuring bacterial growth kinetics after one hour exposure to concentration of 2 x MIC of 10(6) CFUs in Mueller-Hinton broth. Drug removal was by 10-3 dilution of the exposed culture. A PAE was consistently present with imipenem (range 0.8-2.9 hrs), amikacin (range 1.0-4.9 hrs), ciprofloxacin (range 1.4-2.8 hrs). The duration of PAE did not correlate with MIC or Grimont's biotypes.

  1. Performance of a MALDI-TOF MS-based imipenem hydrolysis assay incorporating zinc sulfate.

    PubMed

    Knox, James; Palombo, Enzo

    2017-03-01

    A MALDI-TOF MS(1)-based imipenem hydrolysis assay was modified by adding ZnSO4. This improved detection of metallo-β-lactamase producing strains without compromising detection of other carbapenemase types. Using 129 genetically characterized Gram-negative bacilli, the sensitivity and specificity were 98.5% (95% confidence interval [CI]: 91.9-99.7%) and 100% (95% CI: 94.3-100%), respectively.

  2. Imipenem Treatment Induces Expression of Important Genes and Phenotypes in a Resistant Acinetobacter baumannii Isolate

    PubMed Central

    AbuBakar, Sazaly; Cerqueira, Gustavo Maia; Al-Haroni, Mohammed; Pang, Sui Ping

    2015-01-01

    Acinetobacter baumannii has emerged as a notorious multidrug-resistant pathogen, and development of novel control measures is of the utmost importance. Understanding the factors that play a role in drug resistance may contribute to the identification of novel therapeutic targets. Pili are essential for A. baumannii adherence to and biofilm formation on abiotic surfaces as well as virulence. In the present study, we found that biofilm formation was significantly induced in an imipenem-resistant (Impr) strain treated with a subinhibitory concentration of antibiotic compared to that in an untreated control and an imipenem-susceptible (Imps) isolate. Using microarray and quantitative PCR analyses, we observed that several genes responsible for the synthesis of type IV pili were significantly upregulated in the Impr but not in the Imps isolate. Notably, this finding is corroborated by an increase in the motility of the Impr strain. Our results suggest that the ability to overproduce colonization factors in response to imipenem treatment confers biological advantage to A. baumannii and may contribute to clinical success. PMID:26666943

  3. Escherichia coli Overexpressing a Baeyer-Villiger Monooxygenase from Acinetobacter radioresistens Becomes Resistant to Imipenem

    PubMed Central

    Minerdi, Daniela; Zgrablic, Ivan; Castrignanò, Silvia; Catucci, Gianluca; Medana, Claudio; Terlizzi, Maria Elena; Gribaudo, Giorgio; Gilardi, Gianfranco

    2015-01-01

    Antimicrobial resistance is a global issue currently resulting in the deaths of hundreds of thousands of people a year worldwide. Data present in the literature illustrate the emergence of many bacterial species that display resistance to known antibiotics; Acinetobacter spp. are a good example of this. We report here that Acinetobacter radioresistens has a Baeyer-Villiger monooxygenase (Ar-BVMO) with 100% amino acid sequence identity to the ethionamide monooxygenase of multidrug-resistant (MDR) Acinetobacter baumannii. Both enzymes are only distantly phylogenetically related to other canonical bacterial BVMO proteins. Ar-BVMO not only is capable of oxidizing two anticancer drugs metabolized by human FMO3, danusertib and tozasertib, but also can oxidize other synthetic drugs, such as imipenem. The latter is a member of the carbapenems, a clinically important antibiotic family used in the treatment of MDR bacterial infections. Susceptibility tests performed by the Kirby-Bauer disk diffusion method demonstrate that imipenem-sensitive Escherichia coli BL21 cells overexpressing Ar-BVMO become resistant to this antibiotic. An agar disk diffusion assay proved that when imipenem reacts with Ar-BVMO, it loses its antibiotic property. Moreover, an NADPH consumption assay with the purified Ar-BVMO demonstrates that this antibiotic is indeed a substrate, and its product is identified by liquid chromatography-mass spectrometry to be a Baeyer-Villiger (BV) oxidation product of the carbonyl moiety of the β-lactam ring. This is the first report of an antibiotic-inactivating BVMO enzyme that, while mediating its usual BV oxidation, also operates by an unprecedented mechanism of carbapenem resistance. PMID:26459905

  4. Escherichia coli Overexpressing a Baeyer-Villiger Monooxygenase from Acinetobacter radioresistens Becomes Resistant to Imipenem.

    PubMed

    Minerdi, Daniela; Zgrablic, Ivan; Castrignanò, Silvia; Catucci, Gianluca; Medana, Claudio; Terlizzi, Maria Elena; Gribaudo, Giorgio; Gilardi, Gianfranco; Sadeghi, Sheila J

    2015-10-12

    Antimicrobial resistance is a global issue currently resulting in the deaths of hundreds of thousands of people a year worldwide. Data present in the literature illustrate the emergence of many bacterial species that display resistance to known antibiotics; Acinetobacter spp. are a good example of this. We report here that Acinetobacter radioresistens has a Baeyer-Villiger monooxygenase (Ar-BVMO) with 100% amino acid sequence identity to the ethionamide monooxygenase of multidrug-resistant (MDR) Acinetobacter baumannii. Both enzymes are only distantly phylogenetically related to other canonical bacterial BVMO proteins. Ar-BVMO not only is capable of oxidizing two anticancer drugs metabolized by human FMO3, danusertib and tozasertib, but also can oxidize other synthetic drugs, such as imipenem. The latter is a member of the carbapenems, a clinically important antibiotic family used in the treatment of MDR bacterial infections. Susceptibility tests performed by the Kirby-Bauer disk diffusion method demonstrate that imipenem-sensitive Escherichia coli BL21 cells overexpressing Ar-BVMO become resistant to this antibiotic. An agar disk diffusion assay proved that when imipenem reacts with Ar-BVMO, it loses its antibiotic property. Moreover, an NADPH consumption assay with the purified Ar-BVMO demonstrates that this antibiotic is indeed a substrate, and its product is identified by liquid chromatography-mass spectrometry to be a Baeyer-Villiger (BV) oxidation product of the carbonyl moiety of the β-lactam ring. This is the first report of an antibiotic-inactivating BVMO enzyme that, while mediating its usual BV oxidation, also operates by an unprecedented mechanism of carbapenem resistance.

  5. Successive Emergence of Enterobacter aerogenes Strains Resistant to Imipenem and Colistin in a Patient

    PubMed Central

    Thiolas, Aurélie; Bollet, Claude; La Scola, Bernard; Raoult, Didier; Pagès, Jean-Marie

    2005-01-01

    Enterobacter aerogenes is an agent of hospital-acquired infection that exhibits a remarkable resistance to β-lactam antibiotics during therapy. Five successive isolates of E. aerogenes infecting a patient and exhibiting a multiresistance phenotype to β-lactam antibiotics and fluoroquinolones were investigated. Among these clinical strains, four presented resistant phenotypes during successive imipenem and colistin treatments. The involved resistance mechanisms exhibited by the successive isolates were associated with alterations of the outer membrane that caused a porin decrease and lipopolysaccharide modifications. PMID:15793111

  6. Successive emergence of Enterobacter aerogenes strains resistant to imipenem and colistin in a patient.

    PubMed

    Thiolas, Aurélie; Bollet, Claude; La Scola, Bernard; Raoult, Didier; Pagès, Jean-Marie

    2005-04-01

    Enterobacter aerogenes is an agent of hospital-acquired infection that exhibits a remarkable resistance to beta-lactam antibiotics during therapy. Five successive isolates of E. aerogenes infecting a patient and exhibiting a multiresistance phenotype to beta-lactam antibiotics and fluoroquinolones were investigated. Among these clinical strains, four presented resistant phenotypes during successive imipenem and colistin treatments. The involved resistance mechanisms exhibited by the successive isolates were associated with alterations of the outer membrane that caused a porin decrease and lipopolysaccharide modifications.

  7. Pharmacodynamic effects of subinhibitory concentrations of imipenem on Pseudomonas aeruginosa in an in vitro dynamic model.

    PubMed Central

    Maggiolo, F; Taras, A; Frontespezi, S; Legnani, M C; Silanos, M A; Pravettoni, G; Suter, F

    1994-01-01

    The postantibiotic effect (PAE), sub-MIC effect (SME), and postantibiotic sub-MIC effect (PASME) of imipenem on Pseudomonas aeruginosa were investigated with an in vitro dynamic model reproducing in vivo elimination kinetics of the antibiotic. The PASMEs were constantly longer than the corresponding SMEs, but differences between them were not statistically significant. Both PASMEs and SMEs were initially bactericidal and were significantly longer than PAEs. The mean values of both PASMEs and SMEs were over 12 h. SMEs appear to be more relevant for the bacterial growth kinetics than PAEs. PMID:8092847

  8. Clinical Trial of Imipenem/Cilastatin in Severely Burned and Infected Patients

    DTIC Science & Technology

    1987-07-01

    parainfluenzae ventricular F contractions (slight) for one day 7 ...... 43.0 Positive Broncho- Proteus vulgaris , 3 9 Improved Reduced in None 27 pneumonia...34"OT FILE CO.Y CLINICAL TRIAL OF IMIPENEM/CILASTATIN IN SEVERELY BURNED AND INFECTED PATIENTS Gary R. Culbertson, M.D., Albert T. McManus, PH.D., D T...antibiotic nary, two urinary tract, one wound and one bacte re- mia. Treatment was clinically successful in 13patie-; resistant organisms in the

  9. Can we use imipenem and meropenem Vitek 2 MICs for detection of suspected KPC and other-carbapenemase producers among species of Enterobacteriaceae?

    PubMed

    Pasteran, Fernando; Lucero, Celeste; Soloaga, Rolando; Rapoport, Melina; Corso, Alejandra

    2011-02-01

    Imipenem and meropenem Vitek 2 MICs were evaluated for a panel of 104 Enterobacteriaceae for identification of carbapenemase producers. The sensitivity and specificity values for the new CLSI interpretative criteria (CLSI document M100-S20-U, 2010) were 98% and 83% for imipenem and 76% and 83% for meropenem, respectively. We propose an algorithm that is highly sensitive (98%) and specific (94%) for carbapenemase screening based on the combined use of imipenem and meropenem MICs.

  10. Identification and characteristics of imipenem-resistant Acinetobacter baumannii in surgical wards in a Chinese university hospital.

    PubMed

    Wang, Dalin; Ma, Linlin; Wu, Zhenyu; Li, Mingcheng; Li, Xiaohan; Zhang, Wei; Chen, Kun

    2015-03-01

    The aim of this study was to investigate the prevalence and characteristics of imipenem-resistant Acinetobacter baumanni isolated from surgical wards in a university hospital, China. A total of 143 non-duplicate A. baumannii were isolated from 517 inpatients in surgery intensive care units (ICUs), burn wards, and general surgery wards. Of these, 102 isolates of A. baumannii (71.3%) were resistant to imipenem. Among imipenem-resistant isolates, all isolates were resistant to almost all antimicrobial agents except polymyxin E, all isolates were positive for blaOXA-23 and blaOXA-51 in addition to ISAba1, 52 (51%) were positive for blaOXA-58, 8 (7.8%) contained blaVIM-2, which co-harbored with blaOXA-58. Molecular typing revealed the presence of three clones among imipenem-resistant isolates. This study confirmed that A. baumannii strains harboring OXA or VIM type β-lactamases are widely distributed throughout the surgery wards. The data demonstrate that there was a high prevalence of imipenem-resistant A. baumannii infection in the region.

  11. In Vitro Determination of Minimum Inhibitory Concentration of Aqueous Garlic Extract and Imipenem against Staphylococcus aureus and Escherichia coli.

    PubMed

    Saha, S K; Saha, S; Akhter, S M; Khatun, S; Islam, M M; Roy, P

    2016-07-01

    An interventional study was performed to determine and compare the MICs of aqueous garlic extract (AGE) and Imipenem against standard strains of Staphylococcus aureus ATCC 25923 & Eschericha coli ATCC 25922. The study was conducted in Department of Pharmacology and Therapeutics in collaboration with Department of Microbiology, Mymensingh Medical College, Mymensingh, Bangladesh from July 2014 to January 2015. The MIC of AGE and antibiotic Imipenem were determined with the help of broth dilution method. The MIC of AGE was determined as 400μg/ml and 700μg/ml against Staphylococcus aureus, and Escherichia coli respectively and the MIC of Imipenem was 1μg/ml against Staphylococus aureus and 1.5μg/ml against Escherichia coli. The MICs of Imipenem was much lower in comparison to MICs of AGE for the test organisms. The subculture study showed the same results with that of the primary isolates. From the study it was clearly observed that AGE have anti bacterial effect but is not potent like antibiotic Imipenem. In this regard active ingredient present in garlic needs to be separated & purified for further study.

  12. [In vitro and in vivo activities of sulopenem compared with those of imipenem and cephalosporins].

    PubMed

    Nagashima, M; Goto, S; Yoshida, T; Matsunaga, T; Shimohira, H; Ogawa, M

    1996-04-01

    The in vitro and in vivo antibacterial activities of sulopenem (CP-70,429),a new parenteral penem antibiotic, were compared with those of imipenem (IPM), flomoxef, cefuzonam (CZON) and cefotaxime. Sulopenem possessed broad-spectrum activities against Gram-positive bacteria and Gram-negative bacteria. Antibacterial activities of sulopenem against methicillin-sensitive Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Streptococcus pyogenes and Streptococcus pneumoniae were equivalent to or somewhat superior to those of IPM. Against members of the family Enterobacteriaceae, sulopenem was 4- to 260-fold more active than reference antibiotics with broad-spectra. In a killing kinetics study for Haemophilus influenzae, sulopenem showed a 99.9% decrease of viable cells after 8 hours at a concentration of 0.20 micrograms/ml. This effect was obtained at a concentration 8-fold lower than that of IPM. The protective effects of sulopenem in murine experimental systemic infections were superior to those of imipenem/cilastatin. In murine experimental mixed infection with Escherichia coli and Bacteroides fragilis, sulopenem had lower ED50, in other words stronger antimicrobial activities than IPM. The therapeutic effect of sulopenem are related well with its MIC value. In guinea pigs experimental lung infection with Klebsiella pneumoniae, sulopenem was more effective than CZON or cefotiam.

  13. A case of pneumonia caused by Legionella pneumophila serogroup 12 and treated successfully with imipenem.

    PubMed

    Nishizuka, Midori; Suzuki, Hiroki; Ara, Tomoka; Watanabe, Mari; Morita, Mami; Sato, Chisa; Tsuchida, Fumihiro; Seto, Junji; Amemura-Maekawa, Junko; Kura, Fumiaki; Takeda, Hiroaki

    2014-06-01

    The patient was an 83-year-old man hospitalized for Haemophilus influenzae pneumonia, who developed recurrent pneumonia after improvement of the initial episode. Legionella pneumophila serogroup 12 was isolated from the sputum, accompanied by increased serum antibody titers to L. pneumophila serogroup 12. Therefore, the patient was diagnosed as having Legionella pneumonia caused by L. pneumophila serogroup 12. Case reports of pneumonia caused by L. pneumophila serogroup 12 are rare, and the case described herein is the first report of clinical isolation of this organism in Japan. When the genotype was determined by the protocol of The European Working Group for Legionella Infections (Sequence-Based Typing [SBT] for epidemiological typing of L. pneumophila, Version 3.1), the sequence type was ST68. Imipenem/cilastatin therapy was found to be effective for the treatment of Legionella pneumonia in this patient.

  14. Structure of the imipenem-hydrolyzing class A beta-lactamase SME-1 from Serratia marcescens.

    PubMed

    Sougakoff, Wladimir; L'Hermite, Guillaume; Pernot, Lucile; Naas, Thierry; Guillet, Valérie; Nordmann, Patrice; Jarlier, Vincent; Delettré, Jean

    2002-02-01

    The structure of the beta-lactamase SME-1 from Serratia marcescens, a class A enzyme characterized by its significant activity against imipenem, has been determined to 2.13 A resolution. The overall structure of SME-1 is similar to that of other class A beta-lactamases. In the active-site cavity, most of the residues found in SME-1 are conserved among class A beta-lactamases, except at positions 104, 105 and 237, where a tyrosine, a histidine and a serine are found, respectively, and at position 238, which is occupied by a cysteine forming a disulfide bridge with the other cysteine residue located at position 69. The crucial role played by this disulfide bridge in SME-1 was confirmed by site-directed mutagenesis of Cys69 to Ala, which resulted in a mutant unable to confer resistance to imipenem and all other beta-lactam antibiotics tested. Another striking structural feature found in SME-1 was the short distance separating the side chains of the active serine residue at position 70 and the strictly conserved glutamate at position 166, which is up to 1.4 A shorter in SME-1 compared with other class A beta-lactamases. Consequently, the SME-1 structure cannot accommodate the essential catalytic water molecule found between Ser70 and Glu166 in the other class A beta-lactamases described so far, suggesting that a significant conformational change may be necessary in SME-1 to properly position the hydrolytic water molecule involved in the hydrolysis of the acyl-enzyme intermediate.

  15. Molecular analysis of imipenem-resistant Acinetobacter baumannii isolated from US service members wounded in Iraq, 2003–2008

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Clonal spread and global dissemination of imipenem resistant (IR) A. baumannii-A. calcoaceticus complex (ABC) have been reported in recent years. However, the epidemiological features of the IR-ABCs in military treatment facilities (MTFs) have not been systematically studied. In this study, 298 ABC...

  16. Time-kill effect of levofloxacin on multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii: synergism with imipenem and colistin.

    PubMed

    Safarika, A; Galani, I; Pistiki, A; Giamarellos-Bourboulis, E J

    2015-02-01

    In the present study, we challenged the concept that levofloxacin should not be used for the management of ventilator-associated pneumonia (VAP) when minimum inhibitory concentrations (MICs) exceed 2 μg/ml. Multidrug-resistant (MDR) and genetically distinct isolates of Pseudomonas aeruginosa (n = 49) and Acinetobacter baumannii (n = 29) from patients with VAP were exposed over time to levofloxacin, imipenem, colistin and their combinations. Synergy between levofloxacin and imipenem was found in 55.3 % and between levofloxacin and colistin in 90.9 % of isolates of P. aeruginosa within the first 4 h of growth. Synergy with imipenem but not with colistin was dependent of the MIC. Synergy between levofloxacin and imipenem was found in 58.6 % of isolates of A. baumannii after 24 h of growth. Considerable synergy was found between levofloxacin and colistin, reaching 84.8 % of isolates of A.baumannii after 6 h of growth. Synergy was independent from the MIC. These results create hopes that levofloxacin can be used as combination therapy for infections by MDR bacteria.

  17. Phase 2, Dose-Ranging Study of Relebactam with Imipenem-Cilastatin in Subjects with Complicated Intra-abdominal Infection

    PubMed Central

    Lucasti, Christopher; Vasile, Liviu; Sandesc, Dorel; Venskutonis, Donatas; McLeroth, Patrick; Lala, Mallika; Rizk, Matthew L.; Brown, Michelle L.; Losada, Maria C.; Pedley, Alison; Kartsonis, Nicholas A.

    2016-01-01

    Relebactam (REL [MK-7655]) is a novel class A/C β-lactamase inhibitor intended for use with imipenem for the treatment of Gram-negative bacterial infections. REL restores imipenem activity against some resistant strains of Klebsiella and Pseudomonas. In this multicenter, double-blind, controlled trial (NCT01506271), subjects who were ≥18 years of age with complicated intra-abdominal infection were randomly assigned (1:1:1) to receive 250 mg REL, 125 mg REL, or placebo, each given intravenously (i.v.) with 500 mg imipenem-cilastatin (IMI) every 6 h (q6h) for 4 to 14 days. The primary efficacy endpoint was the proportion of microbiologically evaluable (ME) subjects with a favorable clinical response at discontinuation of i.v. therapy (DCIV). A total of 351 subjects were randomized, 347 (99%) were treated, and 255 (73%) were ME at DCIV (55% male; mean age, 49 years). The most common diagnoses were complicated appendicitis (53%) and complicated cholecystitis (17%). Thirty-six subjects (13%) had imipenem-resistant Gram-negative infections at baseline. Both REL doses plus IMI were generally well tolerated and demonstrated safety profiles similar to that of IMI alone. Clinical response rates at DCIV were similar in subjects who received 250 mg REL plus IMI (96.3%) or 125 mg REL plus IMI (98.8%), and both were noninferior to IMI alone (95.2%; one-sided P < 0.001). The treatment groups were also similar with respect to clinical response at early and late follow-up and microbiological response at all visits. Pharmacokinetic/pharmacodynamic simulations show that imipenem exposure at the proposed dose of 500 mg IMI with 250 mg REL q6h provides coverage of >90% of carbapenem-resistant bacterial strains. PMID:27503659

  18. Clinical Validation of Therapeutic Drug Monitoring of Imipenem in Spent Effluent in Critically Ill Patients Receiving Continuous Renal Replacement Therapy: A Pilot Study

    PubMed Central

    Wen, Aiping; Li, Zhe; Yu, Junxian; Li, Ren; Cheng, Sheng; Duan, Meili; Bai, Jing

    2016-01-01

    Objectives The primary objective of this pilot study was to investigate whether the therapeutic drug monitoring of imipenem could be performed with spent effluent instead of blood sampling collected from critically ill patients under continuous renal replacement therapy. Methods A prospective open-label study was conducted in a real clinical setting. Both blood and effluent samples were collected pairwise before imipenem administration and 0.5, 1, 1.5, 2, 3, 4, 6, and 8 h after imipenem administration. Plasma and effluent imipenem concentrations were determined by reversed-phase high-performance liquid chromatography with ultraviolet detection. Pharmacokinetic and pharmacodynamic parameters of blood and effluent samples were calculated. Results Eighty-three paired plasma and effluent samples were obtained from 10 patients. The Pearson correlation coefficient of the imipenem concentrations in plasma and effluent was 0.950 (P<0.0001). The average plasma-to-effluent imipenem concentration ratio was 1.044 (95% confidence interval, 0.975 to 1.114) with Bland-Altman analysis. No statistically significant difference was found in the pharmacokinetic and pharmacodynamic parameters tested in paired plasma and effluent samples with Wilcoxon test. Conclusion Spent effluent of continuous renal replacement therapy could be used for therapeutic drug monitoring of imipenem instead of blood sampling in critically ill patients. PMID:27093294

  19. A randomized trial of 7-day doripenem versus 10-day imipenem-cilastatin for ventilator-associated pneumonia

    PubMed Central

    2012-01-01

    Introduction The aim of this study was to compare a 7-day course of doripenem to a 10-day course of imipenem-cilastatin for ventilator-associated pneumonia (VAP) due to Gram-negative bacteria. Methods This was a prospective, double-blinded, randomized trial comparing a fixed 7-day course of doripenem one gram as a four-hour infusion every eight hours with a fixed 10-day course of imipenem-cilastatin one gram as a one-hour infusion every eight hours (April 2008 through June 2011). Results The study was stopped prematurely at the recommendation of the Independent Data Monitoring Committee that was blinded to treatment arm assignment and performed a scheduled review of data which showed signals that were close to the pre-specified stopping limits. The final analyses included 274 randomized patients. The clinical cure rate at the end of therapy (EOT) in the microbiological intent-to-treat (MITT) population was numerically lower for patients in the doripenem arm compared to the imipenem-cilastatin arm (45.6% versus 56.8%; 95% CI, -26.3% to 3.8%). Similarly, the clinical cure rate at EOT was numerically lower for patients with Pseudomonas aeruginosa VAP, the most common Gram-negative pathogen, in the doripenem arm compared to the imipenem-cilastatin arm (41.2% versus 60.0%; 95% CI, -57.2 to 19.5). All cause 28-day mortality in the MITT group was numerically greater for patients in the doripenem arm compared to the imipenem-cilastatin arm (21.5% versus 14.8%; 95% CI, -5.0 to 18.5) and for patients with P. aeruginosa VAP (35.3% versus 0.0%; 95% CI, 12.6 to 58.0). Conclusions Among patients with microbiologically confirmed late-onset VAP, a fixed 7-day course of doripenem was found to have non-significant higher rates of clinical failure and mortality compared to a fixed 10-day course of imipenem-cilastatin. Consideration should be given to treating patients with VAP for more than seven days to optimize clinical outcome. Trial Registration ClinicalTrials.gov: NCT00589693

  20. An adaptive response of Enterobacter aerogenes to imipenem: regulation of porin balance in clinical isolates.

    PubMed

    Lavigne, Jean-Philippe; Sotto, Albert; Nicolas-Chanoine, Marie-Hélène; Bouziges, Nicole; Pagès, Jean-Marie; Davin-Regli, Anne

    2013-02-01

    Imipenem (IPM) is a carbapenem antibiotic frequently used in severe hospital infections. Several reports have mentioned the emergence of resistant isolates exhibiting membrane modifications. A study was conducted between September 2005 and August 2007 to survey infections due to Enterobacter aerogenes in patients hospitalised in a French university hospital. Resistant E. aerogenes clinical isolates obtained from patients treated with IPM and collected during the 3 months following initiation of treatment were phenotypically and molecularly characterised for β-lactamases, efflux pumps activity and outer membrane proteins. Among the 339 patients infected with E. aerogenes during the study period, 41 isolates (12.1%) were resistant to extended-spectrum cephalosporins and 17 patients (5.0%) were treated with IPM. The isolates from these 17 patients presented TEM-24 and basal efflux expression. Following IPM treatment, an IPM-intermediate-susceptible (IPM-I) isolate emerged in 11 patients and an IPM-resistant (IPM-R) isolate in 6 patients. A change in the porin balance (Omp35/Omp36) was observed in IPM-I isolates exhibiting ertapenem resistance. Finally, a porin deficiency (Omp35 and Omp36 absence) was detected in IPM-R isolates associated with efflux pump expression. This study indicates that the alteration in porin expression, including the shift of porin expression and lack of porins, contribute to the E. aerogenes adaptive response to IPM treatment.

  1. In vitro activities of amoxicillin-clavulanate, doxycycline, ceftazidime, imipenem, and trimethoprim-sulfamethoxazole against biofilm of Brazilian strains of Burkholderia pseudomallei.

    PubMed

    Bandeira, Tereza de Jesus Pinheiro Gomes; Moreira, Camila Alencar; Brilhante, Raimunda Sâmia Nogueira; Castelo-Branco, Débora de Souza Collares Maia; Neto, Manoel Paiva de Araújo; Cordeiro, Rossana de Aguiar; Rodrigues, Terezinha de Jesus Santos; Rocha, Marcos Fábio Gadelha; Sidrim, José Júlio Costa

    2013-11-01

    This study aimed at investigating the in vitro activities of amoxicillin-clavulanate, doxycycline, ceftazidime, imipenem, and trimethoprim-sulfamethoxazole against Burkholderia pseudomallei in planktonic and biofilm forms, through broth microdilution and resazurin-based viability staining, respectively. In planktonic growth, the strains were susceptible to the drugs, while in biofilm growth, significantly higher antimicrobial concentrations were required, especially for ceftazidime and imipenem, surpassing the resistance breakpoints. These results highlight the importance of the routine evaluation of biofilm antimicrobial susceptibility.

  2. In Vitro Activities of Amoxicillin-Clavulanate, Doxycycline, Ceftazidime, Imipenem, and Trimethoprim-Sulfamethoxazole against Biofilm of Brazilian Strains of Burkholderia pseudomallei

    PubMed Central

    Bandeira, Tereza de Jesus Pinheiro Gomes; Moreira, Camila Alencar; Castelo-Branco, Débora de Souza Collares Maia; Neto, Manoel Paiva de Araújo; Cordeiro, Rossana de Aguiar; Rodrigues, Terezinha de Jesus Santos; Rocha, Marcos Fábio Gadelha; Sidrim, José Júlio Costa

    2013-01-01

    This study aimed at investigating the in vitro activities of amoxicillin-clavulanate, doxycycline, ceftazidime, imipenem, and trimethoprim-sulfamethoxazole against Burkholderia pseudomallei in planktonic and biofilm forms, through broth microdilution and resazurin-based viability staining, respectively. In planktonic growth, the strains were susceptible to the drugs, while in biofilm growth, significantly higher antimicrobial concentrations were required, especially for ceftazidime and imipenem, surpassing the resistance breakpoints. These results highlight the importance of the routine evaluation of biofilm antimicrobial susceptibility. PMID:24002089

  3. Time-kill synergy tests of tigecycline combined with imipenem, amikacin, and ciprofloxacin against clinical isolates of multidrug-resistant Klebsiella pneumoniae and Escherichia coli.

    PubMed

    Yim, Haejun; Woo, Heungjeong; Song, Wonkeun; Park, Min-Jeong; Kim, Hyun Soo; Lee, Kyu Man; Hur, Jun; Park, Man-Seung

    2011-01-01

    This study evaluated the activity of tigecycline combined with imipenem, amikacin, and ciprofloxacin against clinical isolates of multidrug-resistant Klebsiella pneumoniae and Escherichia coli co-producing extended-spectrum β-lactamases and acquired AmpC β-lactamases. Broth microdilution tests were performed for cefotaxime, ceftazidime, cefepime, imipenem, amikacin, ciprofloxacin, and tigecycline. Time-kill synergy studies were tested for tigecycline plus imipenem, tigecycline plus amikacin, and tigecycline plus ciprofloxacin. Imipenem (MIC(90) = 1 μg/ml for both K. pneumoniae and E. coli) and tigecycline (MIC(90) = 2 μg/ml for K. pneumoniae and 1 μg/ml for E. coli) were the most potent agents. Combination studies with tigecycline plus imipenem resulted in synergy against 18 K. pneumoniae and 3 E. coli isolates; tigecycline plus amikacin yielded synergy against 8 K. pneumoniae and 3 E. coli isolates; tigecycline plus ciprofloxacin yielded synergy against 7 K. pneumoniae and 2 E. coli isolates. No antagonism was observed with any combination. In the present study, imipenem, amikacin, and ciprofloxacin led to indifferent and some synergistic effects in combination with tigecycline, and none of them demonstrated antagonistic effects.

  4. An OXA-66/OXA-51-like carbapenemase and possibly an efflux pump are associated with resistance to imipenem in Acinetobacter baumannii.

    PubMed

    Hu, Wensi S; Yao, Shu-Man; Fung, Chang-Phone; Hsieh, Yi-Ping; Liu, Chang-Pan; Lin, Jing-Fang

    2007-11-01

    We investigated the mechanisms involved in imipenem resistance in 23 clinical strains of Acinetobacter baumannii. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed the presence of a 30-kDa protein in imipenem-intermediate A. baumannii (IIAB) and imipenem-resistant A. baumannii (IRAB) strains; this protein was almost undetectable in imipenem-susceptible A. baumannii (ISAB) strains. The 30-kDa protein was identified as an OXA-51-like carbapenemase using two-dimensional gel electrophoresis and mass spectrometry. Similar to other recent findings, bla(OXA-51-like) genes were found to exist in all 23 clinical strains; however, the transcript levels of bla(OXA-51-like) in the IIAB and IRAB were higher than in the ISAB strains using reverse transcriptase PCR (RT-PCR) and real-time RT-PCR assays. This change was due to the presence of an insertion sequence, ISAba1, upstream of bla(OXA-51-like) in the IIAB and IRAB strains that was not present in the ISAB strains. The introduction of bla(OXA-66) (a bla(OXA-51)(-like) gene), identified in ISAB ab1254 and IRAB ab1266, into Escherichia coli TOP10 cells resulted in 3.95-fold and 7.90-fold elevations in resistance to imipenem, respectively. Furthermore, when ISAB ab8 and ISAB ab1254 and their in vitro-selected imipenem-resistant mutants ISAB ab8(r) and ISAB ab1254(r) were compared, the results showed no change in the bla(OXA-66)/bla(OXA-51-like) gene sequences, in expression of the gene, and in the outer membrane protein profiles. However, there was a four- to eightfold reduction in imipenem resistance upon adding carbonyl cyanide m-chlorophenylhydrazone. Taken together, these results suggest that the OXA-66/OXA-51-like carbapenemase contributes to intrinsic resistance to imipenem; however, drug export by an efflux pump may be more important and/or occur more frequently in imipenem-resistant A. baumannii. Furthermore, this is the first report of a Taiwanese strain of an OXA-66/OXA-51-like

  5. In vitro activity effects of combinations of cephalothin, dicloxacillin, imipenem, vancomycin and amikacin against methicillin-resistant Staphylococcus spp. strains

    PubMed Central

    Miranda-Novales, Guadalupe; Leaños-Miranda, Blanca E; Vilchis-Pérez, Mariano; Solórzano-Santos, Fortino

    2006-01-01

    Background combinations of drugs has been proposed as an alternative for oxacillin-resistant staphylococci infections, however, limited information about in vitro combinations are available for multi-resistant strains. The objective of this study was to describe the interaction of beta-lactams in combination with vancomycin or amikacin against 26 oxacillin and amikacin-resistant nosocomial Staphylococcus spp. isolates. Methods activity of dicloxacillin plus amikacin, cephalothin plus amikacin, cephalothin plus vancomycin, imipenem plus vancomycin and vancomycin plus amikacin was evaluated by checkerboard synergy tests and the fractional inhibitory concentration index (FIC) was calculated. Results: dicloxacillin plus amikacin, and cephalothin plus amikacin were synergistic or partially synergistic in 84.6% and 100% respectively. For nearly half of the isolates the mean concentrations of dicloxacillin, cephalothin and amikacin at which FIC indexes were calculated were achievable therapeutically. Vancomycin plus amikacin had synergistic effect only against two isolates, and partially synergistic in 38.6%. For the combinations vancomycin plus cephalothin and vancomycin plus imipenem the effect was additive in 76.9% and 80.7% respectively. Conclusion in this study the checkerboard analysis showed that amikacin in combination with cephalothin or dicloxacillin was synergistic against most of the resistant strains of S. aureus and coagulase-negative Staphylococcus. Vancomycin in combination with a beta-lactam (cephalothin or imipenem) showed additivity. An indifferent effect predominated for the combination vancomycin plus amikacin. Even though a synergistic effect is expected when using a beta-lactam plus amikacin combination, it is possible that the effect cannot be clinically achievable. Careful selection of antimicrobial combinations and initial MICs are mandatory for future evaluations. PMID:17034644

  6. Treatment of severe pneumonia in hospitalized patients: results of a multicenter, randomized, double-blind trial comparing intravenous ciprofloxacin with imipenem-cilastatin. The Severe Pneumonia Study Group.

    PubMed Central

    Fink, M P; Snydman, D R; Niederman, M S; Leeper, K V; Johnson, R H; Heard, S O; Wunderink, R G; Caldwell, J W; Schentag, J J; Siami, G A

    1994-01-01

    Intravenously administered ciprofloxacin was compared with imipenem for the treatment of severe pneumonia. In this prospective, randomized, double-blind, multicenter trial, which included an intent-to-treat analysis, a total of 405 patients with severe pneumonia were enrolled. The mean APACHE II score was 17.6, 79% of the patients required mechanical ventilation, and 78% had nosocomial pneumonia. A subgroup of 205 patients (98 ciprofloxacin-treated patients and 107 imipenem-treated patients) were evaluable for the major efficacy endpoints. Patients were randomized to receive intravenous treatment with either ciprofloxacin (400 mg every 8 h) or imipenem (1,000 mg every 8 h), and doses were adjusted for renal function. The primary and secondary efficacy endpoints were bacteriological and clinical responses at 3 to 7 days after completion of therapy. Ciprofloxacin-treated patients had a higher bacteriological eradication rate than did imipenem-treated patients (69 versus 59%; 95% confidence interval of -0.6%, 26.2%; P = 0.069) and also a significantly higher clinical response rate (69 versus 56%; 95% confidence interval of 3.5%, 28.5%; P = 0.021). The greatest difference between ciprofloxacin and imipenem was in eradication of members of the family Enterobacteriaceae (93 versus 65%; P = 0.009). Stepwise logistic regression analysis demonstrated the following factors to be associated with bacteriological eradication: absence of Pseudomonas aeruginosa (P < 0.01), higher weight (P < 0.01), a low APACHE II score (P = 0.03), and treatment with ciprofloxacin (P = 0.04). When P. aeruginosa was recovered from initial respiratory tract cultures, failure to achieve bacteriological eradication and development of resistance during therapy were common in both treatment groups (67 and 33% for ciprofloxacin and 59 and 53% for imipenem, respectively). Seizures were observed more frequently with imipenem than with ciprofloxacin (6 versus 1%; P = 0.028). These results demonstrate that

  7. [Clinical and pharmacokinetic evaluation of imipenem/cilastatin sodium in children].

    PubMed

    Fujita, K; Kakehashi, H; Murono, K; Sakata, H; Ohmi, H; Yoshioka, H; Maruyama, S; Sanae, N; Inyaku, F

    1986-07-01

    Nineteen episodes of infection in 17 children (one had 3 episodes) were treated with imipenem/cilastatin sodium (MK-0787/MK-0791), and the clinical efficacy and side effects were evaluated. The ages of patients ranged from 1 month to 8 years 1 month and their body weights ranged from 3.9 to 25.2 kg. The MK-0787/MK-0791 was administered intravenously by a 30-60 minutes infusion, in doses ranging from 8-42 mg/8-42 mg/kg every 6 to 12 hours for 3 to 40.5 days. Among 18 episodes in 16 patients (one patient proved to have rubella meningoencephalitis and was excluded from evaluation of the clinical efficacy) with bacterial infections including sepsis, pneumonia, acute suppurative thyroiditis and urinary tract infections, the results were excellent in 10, good in 5, fair in 2, and poor in 1 episode. Some side effects were noted; among all 19 episodes in the 17 patients diarrhea was noted in 3, rash in 1, slightly elevated serum transaminases in 1 and thrombocytosis in 1 episode. Pharmacokinetic studies were done in 7 patients whose ages ranged from 3 years 2 months to 13 years 1 month. Plasma concentrations of MK-0787 in 2 children were 19.6 and 20.0 micrograms/ml at 15 minutes and 5.6 and 2.1 micrograms/ml at 2 hours after a 10 mg/10 mg/kg intravenous 30-minute drip infusion of MK-0787/MK-0791. Plasma half-lives of MK-0787 were 1.52 and 0.74 hour, and total urinary recoveries were 54.6 and 71.4% during 0-6 hours. After a 20 mg/20 mg/kg intravenous 30-minute drip infusion into 2 other children, plasma concentrations of MK-0787 were 46.8 and 44.0 micrograms/ml at 15 minutes and 7.8 and 7.4 micrograms/ml at 2 hours. Plasma half-lives were 0.82 and 0.83 hour, and total urinary recoveries were 110.2 and 80.5% during 0-6 hours. Plasma concentrations of MK-0787 were less than 0.2, 0.2 and 1.2 micrograms/ml just before the next doses in 3 patients given 11-20 mg/11-20 mg/kg of MK-0787/MK-0791 every 6-8 hours. The time course of the plasma levels and urinary excretion in these

  8. [Prevalence of Acinetobacter baumannii and Pseudomonas aeruginosa isolates resistant to imipenem by production of metallo-β-lactamases in Rabat Military Teaching Hospital Mohammed V].

    PubMed

    Gildas Comlan Zohoun, Alban; Moket, Danièle; El Hamzaoui, Sakina

    2013-01-01

    We studied the production of metallo-β-lactamases (MBL) in Acinetobacter baumannii and Pseudomonas aeruginosa strains resistant to imipenem at the Rabat Mohammed V military teaching hospital, according to Yong et al.'s method, using a sterilized solution of EDTA 0.5 M pH 8. One hundred and five bacterial strains (48 A. baumannii and 57 P. aeruginosa) were identified. 45 (42.9%) with 34 A. baumannii and 11 P. aeruginosa were resistant to imipenem. The prevalence of MBL producing strains was 22.2% (10/45). The existence of this isolates resistant to imipenem by producing metallo-β-lactamases is an emerging public health problem. It is necessary to implemente infection control programs to avoid spreading of multidrug resistant bacteria.

  9. Comparison of effectiveness and safety of imipenem/clavulanate- versus meropenem/clavulanate-containing regimens in the treatment of MDR- and XDR-TB.

    PubMed

    Tiberi, Simon; Sotgiu, Giovanni; D'Ambrosio, Lia; Centis, Rosella; Abdo Arbex, Marcos; Alarcon Arrascue, Edith; Alffenaar, Jan Willem; Caminero, Jose A; Gaga, Mina; Gualano, Gina; Skrahina, Alena; Solovic, Ivan; Sulis, Giorgia; Tadolini, Marina; Alarcon Guizado, Valentina; De Lorenzo, Saverio; Roby Arias, Aurora Jazmín; Scardigli, Anna; Akkerman, Onno W; Aleksa, Alena; Artsukevich, Janina; Auchynka, Vera; Bonini, Eduardo Henrique; Chong Marín, Félix Antonio; Collahuazo López, Lorena; de Vries, Gerard; Dore, Simone; Kunst, Heinke; Matteelli, Alberto; Moschos, Charalampos; Palmieri, Fabrizio; Papavasileiou, Apostolos; Payen, Marie-Christine; Piana, Andrea; Spanevello, Antonio; Vargas Vasquez, Dante; Viggiani, Pietro; White, Veronica; Zumla, Alimuddin; Migliori, Giovanni Battista

    2016-06-01

    No large study to date has ever evaluated the effectiveness, safety and tolerability of imipenem/clavulanate versus meropenem/clavulanate to treat multidrug- and extensively drug-resistant tuberculosis (MDR- and XDR-TB). The aim of this observational study was to compare the therapeutic contribution of imipenem/clavulanate versus meropenem/clavulanate added to background regimens to treat MDR- and XDR-TB cases.84 patients treated with imipenem/clavulanate-containing regimens showed a similar median number of antibiotic resistances (8 versus 8) but more fluoroquinolone resistance (79.0% versus 48.9%, p<0.0001) and higher XDR-TB prevalence (67.9% versus 49.0%, p=0.01) in comparison with 96 patients exposed to meropenem/clavulanate-containing regimens. Patients were treated with imipenem/clavulanate- and meropenem/clavulanate-containing regimens for a median (interquartile range) of 187 (60-428) versus 85 (49-156) days, respectively.Statistically significant differences were observed on sputum smear and culture conversion rates (79.7% versus 94.8%, p=0.02 and 71.9% versus 94.8%, p<0.0001, respectively) and on success rates (59.7% versus 77.5%, p=0.03). Adverse events to imipenem/clavulanate and meropenem/clavulanate were reported in 5.4% and 6.5% of cases only.Our study suggests that meropenem/clavulanate is more effective than imipenem/clavulanate in treating MDR/XDR-TB patients.

  10. Molecular detection of metallo-β-lactamase gene blaVIM-1 in imipenem-resistant Pseudomonas aeruginosa strains isolated from hospitalized patients in the hospitals of Isfahan

    PubMed Central

    Sedighi, Mansour; Vaez, Hamid; Moghoofeie, Mohsen; Hadifar, Shima; Oryan, Golfam; Faghri, Jamshid

    2015-01-01

    Background: Pseudomonas aeruginosa is an opportunistic human pathogen that causes serious problems, especially in people, who have immunodeficiency. In recent times, metallo-β-lactamase (MBLs) resistance in this bacterium has led to some difficulties in treating bacterial infections. The metallo-beta-lactamase family of genes, including blaVIM-1, is being reported with increasing frequency worldwide. The aim of this study is the detection of the metallo-β-lactamase gene blaVIM-1 in imipenem-resistant P. aeruginosa (IRPA) strains isolated from hospitalized patients. Materials and Methods: In this study, 106 P. aeruginosa samples were isolated from various nosocomial infections. The isolates were identified, tested for susceptibility to various antimicrobial agents by the Kirby-Bauer disk diffusion method, and all the imipenem-resistant isolates were screened for the presence of MBLs by using the combined disk (IMP-EDTA). The minimal inhibitory concentration (MIC) of imipenem was determined by E-test on the Mueller-Hinton agar. To detect the blaVIM-1 gene, the isolates were subjected to a polymerase chain reaction (PCR). Results: Of all the P. aeruginosa isolates, 62 (58.5%) were found to be imipenem-resistant P. aeruginosa (MIC ≥32 μg/ml). Twenty-six (42%) of the imipenem-resistant isolates were MBL positive. None of these isolates carried the blaVIM-1 gene using the PCR assay. Conclusion: The results demonstrated the serious therapeutic threat of the MBL-producing P. aeruginosa populations. The rate of imipenem resistance due to MBL was increased dramatically. Early detection and infection-control practices are the best antimicrobial strategies for this organism. None of MBL-producing isolates in this study carry the blaVIM-1 gene; therefore, another gene in the MBL family should be investigated. PMID:25802826

  11. Molecular analysis of imipenem-resistant Acinetobacter baumannii isolated from US service members wounded in Iraq, 2003-2008.

    PubMed

    Huang, X-Z; Chahine, M A; Frye, J G; Cash, D M; Lesho, E P; Craft, D W; Lindler, L E; Nikolich, M P

    2012-12-01

    Global dissemination of imipenem-resistant (IR) clones of Acinetobacter baumannii - A. calcoaceticus complex (ABC) have been frequently reported but the molecular epidemiological features of IR-ABC in military treatment facilities (MTFs) have not been described. We characterized 46 IR-ABC strains from a dataset of 298 ABC isolates collected from US service members hospitalized in different US MTFs domestically and overseas during 2003-2008. All IR strains carried the bla(OXA-51) gene and 40 also carried bla(OXA-23) on plasmids and/or chromosome; one carried bla(OXA-58) and four contained ISAbal located upstream of bla(OXA-51). Strains tended to cluster by pulsed-field gel electrophoresis profiles in time and location. Strains from two major clusters were identified as international clone I by multilocus sequence typing.

  12. Individual or Combined Effects of Meropenem, Imipenem, Sulbactam, Colistin, and Tigecycline on Biofilm-Embedded Acinetobacter baumannii and Biofilm Architecture

    PubMed Central

    Wang, Yung-Chih; Kuo, Shu-Chen; Yang, Ya-Sung; Lee, Yi-Tzu; Chiu, Chun-Hsiang; Chuang, Ming-Fen; Lin, Jung-Chung; Chang, Feng-Yee

    2016-01-01

    Acinetobacter baumannii biofilms are difficult to eradicate. We investigated the effects of meropenem (2 mg/liter), imipenem (2 mg/liter), sulbactam (4 mg/liter), colistin (2 mg/liter), and tigecycline (2 mg/liter), alone or in combination, on biofilm-embedded carbapenem-resistant and carbapenem-susceptible A. baumannii (CRAb and CSAb, respectively) cells, as well as on the architecture of the biofilms. A. baumannii ATCC 15151 (Ab15151) and its OXA-82-overproducing transformant, along with two clinical CSAb and two clinical CRAb isolates of differing clonalities, were used. The minimal bactericidal concentrations for biofilm-embedded cells of the six tested isolates were >50-fold those of their planktonic cells. When used individually, meropenem exhibited a higher killing effect than the other four antimicrobials on biofilm-embedded CSAb cells in the colony biofilm assay. For two clinical CRAb isolates, meropenem plus sulbactam or sulbactam plus tigecycline showed >100-fold the bactericidal effect exhibited by these agents used alone after 48 h of treatment. The effect of antimicrobials on the architecture of Ab15151 biofilm emitting green fluorescence was determined by confocal laser scanning microscopy using COMSTAT software. Significant decreases in the maximum biofilm thickness were observed after exposure to meropenem and imipenem. Meropenem plus sulbactam significantly decreased the biomass and mean thickness and increased the roughness coefficient of biofilms, but sulbactam plus tigecycline only decreased the maximum and mean biofilm thickness compared to any of these agents used alone. Meropenem was active against biofilm-embedded CSAb, whereas meropenem plus sulbactam exhibited synergism against biofilm-embedded CRAb and caused significantly more damage to the biofilm architecture than did any of the agents used alone. PMID:27216052

  13. Correlation of Oxacillinase Gene Carriage With the Genetic Fingerprints of Imipenem-Resistant Clinical Isolates of Acinetobacter baumannii

    PubMed Central

    Zanganeh, Zahra; Eftekhar, Fereshteh

    2015-01-01

    Background: Emergence of multidrug-resistant Acinetobacter baumannii has resulted in the treatment failure of related infections and an increase in patient mortality. The presence of class D β-lactamases (oxacillinases) in this organism is an important mechanism underlying resistance to beta-lactam antibiotics. Objectives: The aim of this work was to investigate the correlation between oxacillinase gene carriage and genetic fingerprints in imipenem-resistant burn and non-burn isolates of A. baumannii. Materials and Methods: Fifty-eight A. baumannii isolates were collected from October 2011 to April 2012, which included 28 burn isolates from Shahid Motahari Hospital and 30 non-burn isolates from Imam Hossein Hospital. The minimum inhibitory and minimum bactericidal concentrations (MIC and MBC) of imipenem were measured by the broth microdilution method. The presence of oxacillinase genes (OXA-23-, OXA-24-, OXA-51-, and OXA-58-like genes) was shown using type-specific primers and PCR. Genetic profiles were generated by RAPD-PCR fingerprinting. Results: OXA-23 was observed in 81% of the isolates and its distribution was similar within the two groups. The presence of OXA-51 was shown in 58.6% of the isolates, of which most were burn isolates (67.6%). OXA-24 was present in 20.7% of the isolates, all belonging to the burn group; OXA-58 was not observed in any of the isolates. RAPD-PCR fingerprints revealed two clusters at a similarity level of 70% (A, B). At a similarity level of 85%, nine different groups were observed for burn and non-bun isolates. Conclusions: Our results showed that blaOXA-23 was the most prevalent gene, followed by blaOXA-51, among the burn and non-burn clinical isolates of A. baumannii. BlaOXA-24-like genes were detected at a lower level and were only found among the burn isolates, which also showed higher heterogeneity compared to the non-burn group. PMID:26495112

  14. Individual or Combined Effects of Meropenem, Imipenem, Sulbactam, Colistin, and Tigecycline on Biofilm-Embedded Acinetobacter baumannii and Biofilm Architecture.

    PubMed

    Wang, Yung-Chih; Kuo, Shu-Chen; Yang, Ya-Sung; Lee, Yi-Tzu; Chiu, Chun-Hsiang; Chuang, Ming-Fen; Lin, Jung-Chung; Chang, Feng-Yee; Chen, Te-Li

    2016-08-01

    Acinetobacter baumannii biofilms are difficult to eradicate. We investigated the effects of meropenem (2 mg/liter), imipenem (2 mg/liter), sulbactam (4 mg/liter), colistin (2 mg/liter), and tigecycline (2 mg/liter), alone or in combination, on biofilm-embedded carbapenem-resistant and carbapenem-susceptible A. baumannii (CRAb and CSAb, respectively) cells, as well as on the architecture of the biofilms. A. baumannii ATCC 15151 (Ab15151) and its OXA-82-overproducing transformant, along with two clinical CSAb and two clinical CRAb isolates of differing clonalities, were used. The minimal bactericidal concentrations for biofilm-embedded cells of the six tested isolates were >50-fold those of their planktonic cells. When used individually, meropenem exhibited a higher killing effect than the other four antimicrobials on biofilm-embedded CSAb cells in the colony biofilm assay. For two clinical CRAb isolates, meropenem plus sulbactam or sulbactam plus tigecycline showed >100-fold the bactericidal effect exhibited by these agents used alone after 48 h of treatment. The effect of antimicrobials on the architecture of Ab15151 biofilm emitting green fluorescence was determined by confocal laser scanning microscopy using COMSTAT software. Significant decreases in the maximum biofilm thickness were observed after exposure to meropenem and imipenem. Meropenem plus sulbactam significantly decreased the biomass and mean thickness and increased the roughness coefficient of biofilms, but sulbactam plus tigecycline only decreased the maximum and mean biofilm thickness compared to any of these agents used alone. Meropenem was active against biofilm-embedded CSAb, whereas meropenem plus sulbactam exhibited synergism against biofilm-embedded CRAb and caused significantly more damage to the biofilm architecture than did any of the agents used alone.

  15. The effects of group 1 versus group 2 carbapenems on imipenem-resistant Pseudomonas aeruginosa: an ecological study.

    PubMed

    Carmeli, Yehuda; Lidji, Shiri Klarfeld; Shabtai, Esther; Navon-Venezia, Shiri; Schwaber, Mitchell J

    2011-07-01

    Use of the group 2 carbapenems, imipenem and meropenem, may lead to emergence of Pseudomonas aeruginosa resistance. The group 1 carbapenem ertapenem has limited activity against P. aeruginosa and is not associated with imipenem-resistant P. aeruginosa (IMP-R PA) in vitro. This retrospective, group-level, longitudinal study collected patient, antibiotic use, and resistance data from 2001 to 2005 using a hospital database containing information on 9 medical wards. A longitudinal data time series analysis was done to evaluate the association between carbapenem use (defined daily doses, or DDDs) and IMP-R PA. A total of 139 185 patient admissions were included, with 541 150 antibiotics DDDs prescribed: 4637 DDDs of group 2 carbapenems and 2130 DDDs of ertapenem. A total of 779 IMP-R PA were isolated (5.6 cases/1000 admissions). Univariate analysis found a higher incidence of IMP-R PA with group 2 carbapenems (P < 0.001), aminoglycosides (P = 0.034), and penicillins (P = 0.05), but not with ertapenem. Multivariate analysis showed a yearly increase in incidence of IMP-R-PA (3.8%, P < 0.001). Group 2 carbapenem use was highly associated with IMP-R PA, with a 20% increase in incidence (P = 0.0014) for each 100 DDDs. Group 2 carbapenem use tended to be associated with an increased proportion of IMP-R PA (P = 0.0625) in multivariate analysis. Ertapenem was not associated with IMP-R PA. These data would support preferentially prescribing ertapenem rather than group 2 carbapenems where clinically appropriate.

  16. In Vivo Evolution of Bacterial Resistance in Two Cases of Enterobacter aerogenes Infections during Treatment with Imipenem.

    PubMed

    Philippe, Nadège; Maigre, Laure; Santini, Sébastien; Pinet, Elizabeth; Claverie, Jean-Michel; Davin-Régli, Anne-Véronique; Pagès, Jean-Marie; Masi, Muriel

    2015-01-01

    Infections caused by multidrug resistant (MDR) bacteria are a major concern worldwide. Changes in membrane permeability, including decreased influx and/or increased efflux of antibiotics, are known as key contributors of bacterial MDR. Therefore, it is of critical importance to understand molecular mechanisms that link membrane permeability to MDR in order to design new antimicrobial strategies. In this work, we describe genotype-phenotype correlations in Enterobacter aerogenes, a clinically problematic and antibiotic resistant bacterium. To do this, series of clinical isolates have been periodically collected from two patients during chemotherapy with imipenem. The isolates exhibited different levels of resistance towards multiple classes of antibiotics, consistently with the presence or the absence of porins and efflux pumps. Transport assays were used to characterize membrane permeability defects. Simultaneous genome-wide analysis allowed the identification of putative mutations responsible for MDR. The genome of the imipenem-susceptible isolate G7 was sequenced to closure and used as a reference for comparative genomics. This approach uncovered several loci that were specifically mutated in MDR isolates and whose products are known to control membrane permeability. These were omp35 and omp36, encoding the two major porins; rob, encoding a global AraC-type transcriptional activator; cpxA, phoQ and pmrB, encoding sensor kinases of the CpxRA, PhoPQ and PmrAB two-component regulatory systems, respectively. This report provides a comprehensive analysis of membrane alterations relative to mutational steps in the evolution of MDR of a recognized nosocomial pathogen.

  17. In Vitro Activities of Ertapenem and Imipenem against Clinical Extended Spectrum Beta-Lactamase-Producing Enterobacteriaceae Collected in Military Teaching Hospital Mohammed V of Rabat.

    PubMed

    Elouennass, M; Zohoun, A; El Ameri, A; Alem, N; Kasouati, J; Benlahlou, Y; El Yaagoubi, I; Frikh, M; Lemnouer, A; Benouda, A

    2012-01-01

    Objective. To study the sensitivity level of extended spectrum beta-lactamase-producing Enterobacteriaceae to Carbapenems (Imipenem, Ertapenem) marketed in Morocco and discusses the place of Ertapenem in the treatment of extended spectrum-beta-lactamase-producing. Materials and Methods. A retrospective study of 110 extended spectrum beta-lactamase-producing Enterobacteriaceae. Isolates obtained from blood cultures, superficial and deep pus, and catheters were conducted. The minimum inhibitory concentrations of Imipenem and Ertapenem were done by the E-test. The modified Hodge test was conducted for resistant or intermediate strains. Results. 99.1% of isolates were susceptible to Imipenem. For Ertapenem, 4 were resistant and 4 intermediate. The modified Hodge test was positive for all 08 isolates. A minimum inhibitory concentration comparison of K. pneumoniae, E. cloacae, and E. coli for Imipenem has noted a significant difference between E. cloacae on one hand and E. coli, K. pneumoniae on the other hand (P < 0.01). No significant difference was noted for minimum inhibitory concentration of Ertapenem. Conclusion. Our results confirm in vitro effectiveness of Ertapenem against extended spectrum beta-lactamase-producing Enterobacteriaceae as reported elsewhere. However, the emergence of resistance to Carbapenems revealed by production of carbapenemases in this study confirmed a necessary bacteriological documented infection before using Ertapenem.

  18. Comparative Phosphoproteomics Reveals the Role of AmpC β-lactamase Phosphorylation in the Clinical Imipenem-resistant Strain Acinetobacter baumannii SK17*

    PubMed Central

    Lai, Juo-Hsin; Yang, Jhih-Tian; Chern, Jeffy; Chen, Te-Li; Wu, Wan-Ling; Liao, Jiahn-Haur; Tsai, Shih-Feng; Liang, Suh-Yuen; Chou, Chi-Chi

    2016-01-01

    Nosocomial infectious outbreaks caused by multidrug-resistant Acinetobacter baumannii have emerged as a serious threat to human health. Phosphoproteomics of pathogenic bacteria has been used to identify the mechanisms of bacterial virulence and antimicrobial resistance. In this study, we used a shotgun strategy combined with high-accuracy mass spectrometry to analyze the phosphoproteomics of the imipenem-susceptible strain SK17-S and -resistant strain SK17-R. We identified 410 phosphosites on 248 unique phosphoproteins in SK17-S and 285 phosphosites on 211 unique phosphoproteins in SK17-R. The distributions of the Ser/Thr/Tyr/Asp/His phosphosites in SK17-S and SK17-R were 47.0%/27.6%/12.4%/8.0%/4.9% versus 41.4%/29.5%/17.5%/6.7%/4.9%, respectively. The Ser-90 phosphosite, located on the catalytic motif S88VS90K of the AmpC β-lactamase, was first identified in SK17-S. Based on site-directed mutagenesis, the nonphosphorylatable mutant S90A was found to be more resistant to imipenem, whereas the phosphorylation-simulated mutant S90D was sensitive to imipenem. Additionally, the S90A mutant protein exhibited higher β-lactamase activity and conferred greater bacterial protection against imipenem in SK17-S compared with the wild-type. In sum, our results revealed that in A. baumannii, Ser-90 phosphorylation of AmpC negatively regulates both β-lactamase activity and the ability to counteract the antibiotic effects of imipenem. These findings highlight the impact of phosphorylation-mediated regulation in antibiotic-resistant bacteria on future drug design and new therapies. PMID:26499836

  19. In vitro activity and in vivo animal model efficacy of IB-367 alone and in combination with imipenem and colistin against Gram-negative bacteria.

    PubMed

    Simonetti, Oriana; Cirioni, Oscar; Ghiselli, Roberto; Orlando, Fiorenza; Silvestri, Carmela; Mazzocato, Susanna; Kamysz, Wojciech; Kamysz, Elzbieta; Provinciali, Mauro; Giacometti, Andrea; Guerrieri, Mario; Offidani, Annamaria

    2014-05-01

    The aim of our study was to evaluate the in vitro activity of IB-367 and its bactericidal effect for Pseudomonas aeruginosa and Escherichia coli, associated to a synergic study to test the antibiotic combinations between the peptide and colistin or imipenem. Minimum inhibitory concentrations (MICs), the minimum bactericidal concentrations (MBCs), the synergy test and killing study were carried out to evaluate the IB-367 activity. In the in vivo model, a wound was incised through the panniculus carnosus of BALB/c mice, and then inoculated with 5 × 107 colony-forming units of P. aeruginosa and E. coli. For each strain, the study included an infected or not infected group that did not receive any treatment, and five contaminated groups treated with local IB- 367, intraperitoneal imipenem, intraperitoneal colistin, topical IB-367 local plus intraperitoneal imipenem or intraperitoneal colistin. All isolates were inhibited by IB-367 at concentrations of 4-64 mg/l. Killing by IB-367 was shown to be very rapid: its activity on all Gram-negative bacteria was completed within a 40 min exposure period at a concentration of 2 × MIC/l. Synergy was demonstrated when IB-367 was combined with colistin or imipenem. In in vivo studies, the groups treated with topical IB-367 and intraperitoneal colistin showed the best results in terms of bacterial load inhibition either for Pseudomonas or for E. coli. The good in vitro activity and in vivo efficacy, as well as, the synergic interactions with antibiotics suggest that IB-367 is a promising candidate for potential application in the treatment of wound Gram-negative infections.

  20. Detection of blaPER-1 & blaOxa10 among imipenem resistant isolates of Pseudomonas aeruginosa isolated from burn patients hospitalized in Shiraz Burn Hospital

    PubMed Central

    Emami, Amir; Bazargani, Abdollah; Mohammadi, Ali Akbar; Zardosht, Mitra; Seyed Jafari, Seyed Morteza

    2015-01-01

    Background and Objectives: Pseudomonas aeruginosa is one of the most important Gram negative opportunistic bacteria which causes infection among burn patients. Resistance to the antibiotics in this group of bacteria is increased due to the activity of extended spectrum β-lactamase (ESBLs) genes. In the current study, we investigated the prevalence of two genes (blaPER-1 & blaOxa10) related β-lactamase genes among imipenem resistance clinical isolates of P. aeruginosa in hospitalized patients. Materials and Methods: From May 2010 to March 2011, 270 P. aeruginosa isolated from hospitalized burned patients’ wounds in Shiraz Burn Hospital, were tested for Imipenem resistance by disk diffusion method. Presence of ESBLs exo-enzyme, blaPER-1 and blaOxa10 genes were also evaluated in the resistant isolate. Results: 210 (77.7%) of 270 P. aeruginosa isolates were resistant to imipenem. blaPER-1 and blaOxa10 were detected among 168 (80.0%) of imipenem resistant isolates. Furthermore, 160 (76.2%) of them had blaOxa10 gene and 84 (40.0%) of them had blaPER-1 while 63 (30.0%) resistant isolates contained both genes simultaneously. Conclusion: This study showed a high prevalence of blaPER-1 and blaOxa10 genes in hospitalized burn patients in south west of Iran. Therefore, it’s highly recommended to perform such tests routinely to evaluate the resistance pattern in order to better antibiotic selection in the burned patients. PMID:26644867

  1. High minimum inhibitory concentration of imipenem as a predictor of fatal outcome in patients with carbapenem non-susceptible Klebsiella pneumoniae

    PubMed Central

    Wu, Ping-Feng; Chuang, Chien; Su, Chin-Fang; Lin, Yi-Tsung; Chan, Yu-Jiun; Wang, Fu-Der; Chuang, Yin-Ching; Siu, L. Kristopher; Fung, Chang-Phone

    2016-01-01

    Carbapenem resistance in Klebsiella pneumoniae is important because of its increasing prevalence and limited therapeutic options. To investigate the clinical and microbiological characteristics of patients infected or colonized with carbapenem non-susceptible K. pneumoniae (CnsKP) in Taiwan, we conducted a retrospective study at Taipei Veterans General Hospital from January 2012 to November 2013. Carbapenem non-susceptibility was defined as a minimum inhibitory concentration (MIC) of ≥2 mg/L for imipenem or meropenem. A total of 105 cases with CnsKP were identified: 49 patients with infection and 56 patients with colonization. Thirty-one isolates had genes that encoded carbapenemases (29.5%), including K. pneumoniae carbapenemase (KPC)-2 (n = 27), KPC-3 (n = 1), VIM-1 (n = 1) and IMP-8 (n = 2). The in-hospital mortality among patients with CnsKP was 43.8%. A MIC for imipenem ≥16 μg/mL, nasogastric intubation and Acute Physiology and Chronic Health Evaluation II score were independent risk factors for in-hospital mortality for all patients with CnsKP. A MIC for imipenem ≥16 μg/mL was also an independent risk factor for 14-day mortality in patients with CnsKP. In conclusion, a positive culture for CnsKP was associated with high in-hospital mortality. A high imipenem MIC of CnsKP can predispose a patient to a poor prognosis. PMID:27585787

  2. A novel chitosan-polyethylene oxide nanofibrous mat designed for controlled co-release of hydrocortisone and imipenem/cilastatin drugs.

    PubMed

    Fazli, Yousef; Shariatinia, Zahra; Kohsari, Iraj; Azadmehr, Amirreza; Pourmortazavi, Seied Mahdi

    2016-11-20

    Antimicrobial chitosan-polyethylene oxide (CS-PEO) nanofibrous mats containing ZnO nanoparticles (NPs) and hydrocortisone-imipenem/cilastatin-loaded ZnO NPs were produced by electrospinning technique. The FE-SEM images displayed that the spherical ZnO NPs were ∼70-200nm in size and the CS-PEO nanofibers were very uniform and free of any beads which had average diameters within the range of ∼20-130nm. For all of the nanofibrous mats, the water uptakes were the highest in acidic medium but they were decreased in the buffer and the least swellings were obtained in the alkaline environment. The drug incorporated mat preserved its bactericidal activity even after it was utilized in the release experiment for 8days in the PBS buffer. The hydrocortisone release was increased to 82% within first 12h while the release rate of imipenem/cilastatin was very much slower so that 20% of the drug was released during this period of time suggesting this nanofibrous mat is very suitable to inhibit inflammation (by hydrocortisone) and infection (using imipenem/cilastatin antibiotic and ZnO NPs) principally for the wound dressing purposes.

  3. Molecular typing and resistance mechanisms of imipenem-non-susceptible Klebsiella pneumoniae in Taiwan: results from the Taiwan surveillance of antibiotic resistance (TSAR) study, 2002-2009.

    PubMed

    Ma, Ling; Lu, Po-Liang; Siu, L Kristopher; Hsieh, Min-Han

    2013-01-01

    We investigated the molecular mechanisms and clonality of imipenem-non-susceptible Klebsiella pneumoniae isolates collected during a Taiwan national surveillance programme, between 2002 and 2009. Genes for carbapenemases, plasmid-borne ampC-type genes and extended-spectrum β-lactamase (ESBL) genes were analysed by PCR. The major porin channels OmpK35 and OmpK36 were studied by SDS-PAGE. Molecular typing was performed with pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). Our study revealed that all 29 of the isolates tested were ESBL producers. Of the K. pneumoniae isolates collected in Taiwan from 2002 to 2009, most (84.6 %, 11/13) imipenem-resistant (MIC >2 mg l(-1)) isolates carried the bla(IMP-8) gene. Isolates with an imipenem MIC of 2 mg l(-1) produced ESBLs with or without DHA-1 in combination with OmpK35/36 loss. PFGE analysis revealed that six small clusters of isolates were clonally related. The MLST grouping results were in concordance with the PFGE results. The predominant sequence types (ST) were ST11, ST48 and ST101. Two novel STs, ST1033 and ST1034, were found. The dominant clone in Taiwan, ST11, has been reported worldwide to be associated with various resistance mechanisms.

  4. Identification and Characterization of Imipenem-Resistant Klebsiella pneumoniae and Susceptible Klebsiella variicola Isolates Obtained from the Same Patient.

    PubMed

    Garza-Ramos, Ulises; Moreno-Dominguez, Stephania; Hernández-Castro, Rigoberto; Silva-Sanchez, Jesús; Barrios, Humberto; Reyna-Flores, Fernando; Sanchez-Perez, Alejandro; Carrillo-Casas, Erika M; Sanchez-León, María Carmen; Moncada-Barron, David

    2016-04-01

    Klebsiella variicola, a bacterium closely genetically related to Klebsiella pneumoniae, is commonly misidentified as K. pneumoniae by biochemical tests. To distinguish between the two bacteria, phylogenetic analysis of the rpoB gene and the identification of unique genes in both bacterial species by multiplex-polymerase chain reaction (PCR) provide the means to reliably identify and genotype K. variicola. In recent years, K. variicola has been described both as the cause of an intrahospital outbreak in a pediatric hospital, which resulted in sepsis in inpatients, and as a frequent cause of bloodstream infections. In the present study, K. pneumoniae and K. variicola were isolated from a unique patient displaying different antimicrobial susceptibility phenotypes and different genotypes of virulence determinants. Eight clinical isolates were obtained at different time intervals; all during a 5-month period. The isolates were identified as K. pneumoniae by an automated identification system. The clinical (biochemical test) and molecular (multiplex-PCR and rpoB gene) characterization identified imipenem resistance in the first six K. pneumoniae ST258 isolates, which encode the SHV-12 cephalosporinase and KPC-3 carbapenemase genes. The two last remaining isolates corresponded to susceptible K. variicola. The bacterial species showed a specific profile of virulence-associated determinants, specifically the fimA, fimH, and ecpRAB fimbrial-encoding genes identified only in K. pneumoniae isolates. However, the entb (enterobactin), mrkD (fimbrial adhesin), uge (epimerase), ureA (urease), and wabG (transferase) genes were shared between both bacterial species. Recent studies attribute a higher mortality rate to K. variicola than to K. pneumonia. This work highlights the identification of K. pneumoniae and the closely related K. variicola isolated from the same patient. The value of distinguishing between these two bacterial species is in their clinical significance, their

  5. Spectrophotometric and chemometric methods for determination of imipenem, ciprofloxacin hydrochloride, dexamethasone sodium phosphate, paracetamol and cilastatin sodium in human urine

    NASA Astrophysics Data System (ADS)

    El-Kosasy, A. M.; Abdel-Aziz, Omar; Magdy, N.; El Zahar, N. M.

    2016-03-01

    New accurate, sensitive and selective spectrophotometric and chemometric methods were developed and subsequently validated for determination of Imipenem (IMP), ciprofloxacin hydrochloride (CIPRO), dexamethasone sodium phosphate (DEX), paracetamol (PAR) and cilastatin sodium (CIL) in human urine. These methods include a new derivative ratio method, namely extended derivative ratio (EDR), principal component regression (PCR) and partial least-squares (PLS) methods. A novel EDR method was developed for the determination of these drugs, where each component in the mixture was determined by using a mixture of the other four components as divisor. Peak amplitudes were recorded at 293.0 nm, 284.0 nm, 276.0 nm, 257.0 nm and 221.0 nm within linear concentration ranges 3.00-45.00, 1.00-15.00, 4.00-40.00, 1.50-25.00 and 4.00-50.00 μg mL- 1 for IMP, CIPRO, DEX, PAR and CIL, respectively. PCR and PLS-2 models were established for simultaneous determination of the studied drugs in the range of 3.00-15.00, 1.00-13.00, 4.00-12.00, 1.50-9.50, and 4.00-12.00 μg mL- 1 for IMP, CIPRO, DEX, PAR and CIL, respectively, by using eighteen mixtures as calibration set and seven mixtures as validation set. The suggested methods were validated according to the International Conference of Harmonization (ICH) guidelines and the results revealed that they were accurate, precise and reproducible. The obtained results were statistically compared with those of the published methods and there was no significant difference.

  6. Spectrophotometric and chemometric methods for determination of imipenem, ciprofloxacin hydrochloride, dexamethasone sodium phosphate, paracetamol and cilastatin sodium in human urine.

    PubMed

    El-Kosasy, A M; Abdel-Aziz, Omar; Magdy, N; El Zahar, N M

    2016-03-15

    New accurate, sensitive and selective spectrophotometric and chemometric methods were developed and subsequently validated for determination of Imipenem (IMP), ciprofloxacin hydrochloride (CIPRO), dexamethasone sodium phosphate (DEX), paracetamol (PAR) and cilastatin sodium (CIL) in human urine. These methods include a new derivative ratio method, namely extended derivative ratio (EDR), principal component regression (PCR) and partial least-squares (PLS) methods. A novel EDR method was developed for the determination of these drugs, where each component in the mixture was determined by using a mixture of the other four components as divisor. Peak amplitudes were recorded at 293.0 nm, 284.0 nm, 276.0 nm, 257.0 nm and 221.0 nm within linear concentration ranges 3.00-45.00, 1.00-15.00, 4.00-40.00, 1.50-25.00 and 4.00-50.00 μg mL(-1) for IMP, CIPRO, DEX, PAR and CIL, respectively. PCR and PLS-2 models were established for simultaneous determination of the studied drugs in the range of 3.00-15.00, 1.00-13.00, 4.00-12.00, 1.50-9.50, and 4.00-12.00 μg mL(-1) for IMP, CIPRO, DEX, PAR and CIL, respectively, by using eighteen mixtures as calibration set and seven mixtures as validation set. The suggested methods were validated according to the International Conference of Harmonization (ICH) guidelines and the results revealed that they were accurate, precise and reproducible. The obtained results were statistically compared with those of the published methods and there was no significant difference.

  7. Imipenem and Cilastatin Injection

    MedlinePlus

    ... treat certain serious infections that are caused by bacteria, including endocarditis (infection of the heart lining and ... medications called carbapenem antibiotics. It works by killing bacteria. Cilastatin is in a class of medications called ...

  8. Imipenem-resistant Acinetobacter baumannii carrying the ISAba1-bla OXA-23,51 and ISAba1-bla ADC-7 genes in Monteria, Colombia.

    PubMed

    Martínez, Pedro; Mattar, Salim

    2012-10-01

    The purpose of this study was to identify the genes coding for resistance to ceftazidime and imipenem and describe the molecular epidemiology of A. baumannii strains isolated from a clinical center in Colombia. Twenty isolates of imipenem-resistant A. baumannii from an equal number of patients with nosocomial infections were obtained. Primers were used to amplify genes bla IMP, bla VIM, bla OXA-23, bla OXA-24, bla OXA-58, bla OXA-51 and bla ADC-7. To detect insertion sequences ISAba1/bla OXA-23, ISAba1/bla OXA-51 and ISAba1/bla ADC-7, mapping by PCR using combinations of reverse primers ISAba1 and reverse primers of bla OXA-23, bla OXA-51 and bla ADC-7 were used. The amplification products were purified and cloned into PCR 2.1-TOPO vector and transformed into chemically competent Escherichia coli TOP10. These amplicons were then sequenced. PFGE was performed on DNA of A. baumannii isolates digested with ApaI. Results. The DNA profiles obtained included 9 clusters with, four 2-7 isolates per profile, and 5 single-isolate profiles. Of the 20 isolates resistant to imipenem, 15 carried bla OXA-23 gene, 4 contained ISAba1 upstream of bla OXA-51 gene, and 6 contained ISAba1 upstream of bla OXA-23 gene. Eighteen of these isolates carried the bla ADC-7 gene, with 9 of the isolates having ISAba1 located upstream of this gene. This is the first report of the ISAba1/ADC-7 associated with OXAs genes in A. baumannii isolates from Colombia.

  9. In Vitro Activity of Polymyxin B plus Imipenem, Meropenem, or Tigecycline against KPC-2-Producing Enterobacteriaceae with High MICs for These Antimicrobials

    PubMed Central

    Barth, Natália; Ribeiro, Vanessa B.

    2015-01-01

    We evaluated the in vitro activity of polymyxin B plus imipenem, meropenem, or tigecycline against six KPC-2-producing Enterobacteriaceae strains with high MICs for these antimicrobial agents. Polymyxin B with carbapenems, especially meropenem, were the most active combinations for Klebsiella pneumoniae and Enterobacter cloacae regardless of the polymyxin B concentration used in the time-kill assay. This combination was also synergistic against two Serratia marcescens strains that are intrinsically resistant to polymyxins. Polymyxin B and tigecycline also presented synergistic activity in most experiments. PMID:25801560

  10. In vitro activity of polymyxin B plus imipenem, meropenem, or tigecycline against KPC-2-producing Enterobacteriaceae with high MICs for these antimicrobials.

    PubMed

    Barth, Natália; Ribeiro, Vanessa B; Zavascki, Alexandre P

    2015-01-01

    We evaluated the in vitro activity of polymyxin B plus imipenem, meropenem, or tigecycline against six KPC-2-producing Enterobacteriaceae strains with high MICs for these antimicrobial agents. Polymyxin B with carbapenems, especially meropenem, were the most active combinations for Klebsiella pneumoniae and Enterobacter cloacae regardless of the polymyxin B concentration used in the time-kill assay. This combination was also synergistic against two Serratia marcescens strains that are intrinsically resistant to polymyxins. Polymyxin B and tigecycline also presented synergistic activity in most experiments.

  11. Use of Imipenem To Detect KPC, NDM, OXA, IMP, and VIM Carbapenemase Activity from Gram-Negative Rods in 75 Minutes Using Liquid Chromatography-Tandem Mass Spectrometry

    PubMed Central

    Kulkarni, M. V.; Zurita, A. N.; Pyka, J. S.; Murray, T. S.; Hodsdon, M. E.

    2014-01-01

    Resistance to extended-spectrum β-lactam antibiotics has led to a greater reliance upon carbapenems, but the expression of carbapenemases threatens to limit the utility of these drugs. Current methods to detect carbapenemase activity are suboptimal, requiring prolonged incubations during which ineffective therapy may be prescribed. We previously described a sensitive and specific assay for the detection of carbapenemase activity using ertapenem and liquid chromatography-tandem mass spectrometry (LC-MS/MS). In this study, we assessed 402 Gram-negative rods, including both Enterobacteriaceae and non-Enterobacteriaceae expressing IMP, VIM, KPC, NDM, and/or OXA carbapenemases, by using imipenem, meropenem, and ertapenem with LC-MS/MS assays. LC-MS/MS methods for the detection of intact and hydrolyzed carbapenems from an enrichment broth were developed. No ion suppression was observed, and the limits of detection for all three drugs were below 0.04 μg/ml. The sensitivity and specificity of meropenem and ertapenem for carbapenemase activity among non-Enterobacteriaceae were low, but imipenem demonstrated a sensitivity and specificity of 96% and 95%, respectively, among all Gram-negative rods (GNR) tested, including both Enterobacteriaceae and non-Enterobacteriaceae. LC-MS/MS allows for the analysis of more complex matrices, and this LC-MS/MS assay could easily be adapted for use with primary specimens requiring growth enrichment. PMID:24789180

  12. Molecular characterisation of the metallo-beta-lactamase genes in imipenem-resistant Gram-negative bacteria from a university hospital in southern Taiwan.

    PubMed

    Lee, Mei-Feng; Peng, Chien-Fang; Hsu, Hui-Jine; Chen, Yen-Hsu

    2008-12-01

    In this study, 260 non-replicate imipenem-resistant Gram-negative bacteria isolated between January 2002 and December 2006 were subjected to a screening test for detection of metallo-beta-lactamase (MBL) using the Etest containing imipenem and ethylene diamine tetra-acetic acid (EDTA). Among the 260 strains, 123 (47.3%) appeared to produce MBL. Of these 123 strains, 113 (91.9%) were found by polymerase chain reaction (PCR) to carry MBL genes of types blaVIM-2, blaVIM-3, blaVIM-11 (blaVIM-11a), blaIMP-8 and novel blaIMP-24. One strain of Serratia marcescens harboured two MBL genes (blaVIM-11 and blaIMP-8) simultaneously. Of the 123 strains, 116 strains (94.3%) carrying the intI1 gene and 21 strains carrying integron-associated blaVIM-3, blaVIM-11 and blaIMP-8 genes were identified among Acinetobacter baumannii, Pseudomonas aeruginosa, Acinetobacter haemolyticus and S. marcescens. Using pulsed-field gel electrophoresis (PFGE) and Southern hybridisation with the blaVIM gene probe for I-CeuI-digested genomic DNA, P. aeruginosa 9527 strain harboured two class 1 integron-associated MBL genes in the chromosome, including blaVIM-3-orf2-aacA4 and novel bla(VIM-3)-orf2-aacA4-aadB-aacA4. This is the first description of the blaVIM-11 gene spreading among P. aeruginosa and A. baumannii strains in southern Taiwan. This finding suggests that clinical spread of this blaVIM-11 gene is a matter of great concern for carbapenem resistance in southern Taiwan.

  13. Growth in glucose-based medium and exposure to subinhibitory concentrations of imipenem induce biofilm formation in a multidrug-resistant clinical isolate of Acinetobacter baumannii

    PubMed Central

    2009-01-01

    Background Acinetobacter baumannii is emerging as an important nosocomial pathogen. Multidrug resistance, as well as ability to withstand environmental stresses, makes eradication of A. baumannii difficult, particularly from hospital settings. Results Over a six-year period, 73 isolates of A. baumannii were collected from infected patients in two hospitals in Italy. While 69 out of the 73 isolates displayed identical multidrug antibiotic resistance pattern, they were susceptible to carbapenems. Genetic profiles of these 69 isolates, determined by Pulsed Field Gel Electrophoresis (PFGE), indicated that they were genetically related and could be clustered in a specific clone, called SMAL. We tested the ability of the SMAL clone to form biofilm, an important determinant for bacterial colonization of the human host and for persistence in the hospital environment. Biofilm formation by A. baumannii SMAL, measured as surface adhesion to polystyrene, is strongly affected by growth conditions, being impaired in rich growth media such as LB, while being favoured in glucose-based medium. Surface adhesion in glucose-based media is inhibited by treatment with cellulase, suggesting that it depends on production of cellulose or of a chemically related extracellular polysaccharide. Exposure of A. baumannii SMAL to subinhibitory concentrations of imipenem resulted in biofilm stimulation and increased production of iron uptake proteins. Growth in iron-supplemented medium also stimulated surface adhesion, thus suggesting that increased intracellular iron concentrations might act as an environmental signal for biofilm formation in A. baumannii SMAL. Conclusions Our results indicate that exposure to subinhibitory concentrations of imipenem can stimulate biofilm formation and induce iron uptake in a pathogenic strain of A. baumannii, with potential implications on antibiotic susceptibility and ability to persist in the human host. PMID:20028528

  14. Efficacies of Imipenem, Meropenem, Cefepime, and Ceftazidime in Rats with Experimental Pneumonia Due to a Carbapenem-Hydrolyzing β-Lactamase-Producing Strain of Enterobacter cloacae

    PubMed Central

    Mimoz, Olivier; Leotard, Sophie; Jacolot, Anne; Padoin, Christophe; Louchahi, Kamel; Petitjean, Olivier; Nordmann, Patrice

    2000-01-01

    The antibacterial activities of imipenem-cilastatin, meropenem-cilastatin, cefepime and ceftazidime against Enterobacter cloacae NOR-1, which produces the carbapenem-hydrolyzing β-lactamase NmcA and a cephalosporinase, and against one of its in vitro-obtained ceftazidime-resistant mutant were compared by using an experimental model of pneumonia with immunocompetent rats. The MICs of the β-lactams with an inoculum of 5 log10 CFU/ml were as follows for E. cloacae NOR-1 and its ceftazidime-resistant mutant, respectively: imipenem, 16 and 128 μg/ml, meropenem, 4 and 32 μg/ml, cefepime, <0.03 and 1 μg/ml, and ceftazidime, 1 and 512 μg/ml. The chromosomally located cephalosporinase and carbapenem-hydrolyzing β-lactamase NmcA were inducible by cefoxitin and meropenem in E. cloacae NOR-1, and both were stably overproduced in the ceftazidime-resistant mutant. Renal impairment was induced (uranyl nitrate, 1 mg/kg of body weight) in rats to simulate the human pharmacokinetic parameters for the β-lactams studied. Animals were intratracheally inoculated with 8.5 log10 CFU of E. cloacae, and therapy was initiated 3 h later. At that time, animal lungs showed bilateral pneumonia containing more than 6 log10 CFU of E. cloacae per g of tissue. Despite the relative low MIC of meropenem for E. cloacae NOR-1, the carbapenem-treated rats had no decrease in bacterial counts in their lungs 60 h after therapy onset compared to the counts for the controls, regardless of whether E. cloacae NOR-1 or its ceftazidime-resistant mutant was inoculated. A significant decrease in bacterial titers was observed for the ceftazidime-treated rats infected with E. cloacae NOR-1 only. Cefepime was the only β-lactam tested effective as treatment against infections due to E. cloacae NOR-1 or its ceftazidime-resistant mutant. PMID:10722486

  15. Spread of TEM, VIM, SHV, and CTX-M β-Lactamases in Imipenem-Resistant Gram-Negative Bacilli Isolated from Egyptian Hospitals

    PubMed Central

    Hamdy Mohammed, El sayed; Elsadek Fakhr, Ahmed; Mohammed El sayed, Hanan; Al Johery, Said abd Elmohsen; Abdel Ghani Hassanein, Wesam

    2016-01-01

    Carbapenem-resistant Gram-negative bacilli resulting from β-lactamases have been reported to be an important cause of nosocomial infections and are a critical therapeutic problem worldwide. This study aimed to describe the prevalence of imipenem-resistant Gram-negative bacilli isolates and detection of blaVIM, blaTEM, blaSHV, blaCTX-M-1, and blaCTX-M-9 genes in these clinical isolates in Egyptian hospitals. The isolates were collected from various clinical samples, identified by conventional methods and confirmed by API 20E. Antibiotic susceptibility testing was determined by Kirby-Bauer technique and interpreted according to CLSI. Production of blaVIM, blaTEM, blaSHV, and blaCTX-M genes was done by polymerase chain reaction (PCR). Direct sequencing from PCR products was subsequently carried out to identify and confirm these β-lactamases genes. Out of 65 isolates, (46.1%) Escherichia coli, (26.2%) Klebsiella pneumoniae, and (10.7%) Pseudomonas aeruginosa were identified as the commonest Gram-negative bacilli. 33(50.8%) were imipenem-resistant isolates. 22 isolates (66.7%) carried blaVIM, 24(72.7%) had blaTEM, and 5(15%) showed blaSHV, while 12(36%), 6(18.2%), and 0(0.00%) harbored blaCTX-M-1, blaCTX-M-9, and blaCTX-M-8/25, respectively. There is a high occurrence of β-lactamase genes in clinical isolates and sequence analysis of amplified genes showed differences between multiple SNPs (single nucleotide polymorphism) sites in the same gene among local isolates in relation to published sequences. PMID:27123005

  16. Correlation between the number of Pro-Ala repeats in the EmrA homologue of Acinetobacter baumannii and resistance to netilmicin, tobramycin, imipenem and ceftazidime.

    PubMed

    Nowak-Zaleska, Alicja; Wieczór, Miłosz; Czub, Jacek; Nierzwicki, Łukasz; Kotłowski, Roman; Mikucka, Agnieszka; Gospodarek, Eugenia

    2016-12-01

    Acinetobacter baumannii coccobacilli are dangerous to patients in intensive care units because of their multidrug resistance to antibiotics, developed mainly in the past decade. This study aimed to examine whether there is a significant correlation between the number of Pro-Ala repeats in the CAP01997 protein, the EmrA homologue of A. baumannii, and resistance to antibiotics. A total of 79 multidrug-resistant A. baumannii strains isolated from patients were analysed. Resistance to antibiotics was determined on Mueller-Hinton agar plates using the Kirby-Bauer disk diffusion method. The number of CCTGCA repeats encoding Pro-Ala repeats in CAP01997 was determined by PCR and capillary electrophoresis. The 3D models of CAP01997 containing Pro-Ala repeats were initially generated using RaptorX Structure Prediction server and were assembled with EasyModeller 4.0. The models were embedded in a model bacterial membrane based on structural information from homologous proteins and were refined using 100-ns molecular dynamics simulations. The results of this research show significant correlation between susceptibility to netilmicin, tobramycin and imipenem and the number of repeated Pro-Ala sequences in the CAP01997 protein, a homologue of the Escherichia coli transporter EmrA. Predicted structures suggest potential mechanisms that confer drug resistance by reshaping the cytoplasmic interface between CAP01997 protein and the critical component of the multidrug efflux pump homologous to EmrB. Based on these results, we can conclude that the CAP01997 protein, an EmrA homologue of A. baumannii, confers resistance to netilmicin, tobramycin and imipenem, depending on the number of Pro-Ala repeats.

  17. In vivo transfer of plasmid-encoded ACC-1 AmpC from Klebsiella pneumoniae to Escherichia coli in an infant and selection of impermeability to imipenem in K. pneumoniae.

    PubMed

    Bidet, Philippe; Burghoffer, Béatrice; Gautier, Valérie; Brahimi, Naïma; Mariani-Kurkdjian, Patricia; El-Ghoneimi, Alaa; Bingen, Edouard; Arlet, Guillaume

    2005-08-01

    We describe in vivo selection of a Klebsiella pneumoniae strain with diminished imipenem susceptibility attributable to plasmid-encoded ACC-1 beta-lactamase production and loss of a 36-kDa major outer membrane protein, together with transfer of this plasmid from K. pneumoniae to Escherichia coli in a Tunisian infant.

  18. Inoculum effect on the efficacies of amoxicillin-clavulanate, piperacillin-tazobactam, and imipenem against extended-spectrum β-lactamase (ESBL)-producing and non-ESBL-producing Escherichia coli in an experimental murine sepsis model.

    PubMed

    Docobo-Pérez, F; López-Cerero, L; López-Rojas, R; Egea, P; Domínguez-Herrera, J; Rodríguez-Baño, J; Pascual, A; Pachón, J

    2013-05-01

    Escherichia coli is commonly involved in infections with a heavy bacterial burden. Piperacillin-tazobactam and carbapenems are among the recommended empirical treatments for health care-associated complicated intra-abdominal infections. In contrast to amoxicillin-clavulanate, both have reduced in vitro activity in the presence of high concentrations of extended-spectrum β-lactamase (ESBL)-producing and non-ESBL-producing E. coli bacteria. Our goal was to compare the efficacy of these antimicrobials against different concentrations of two clinical E. coli strains, one an ESBL-producer and the other a non-ESBL-producer, in a murine sepsis model. An experimental sepsis model {~5.5 log10 CFU/g [low inoculum concentration (LI)] or ~7.5 log(10) CFU/g [high inoculum concentration (HI)]} using E. coli strains ATCC 25922 (non-ESBL producer) and Ec1062 (CTX-M-14 producer), which are susceptible to the three antimicrobials, was used. Amoxicillin-clavulanate (50/12.5 mg/kg given intramuscularly [i.m.]), piperacillin-tazobactam (25/3.125 mg/kg given intraperitoneally [i.p.]), and imipenem (30 mg/kg i.m.) were used. Piperacillin-tazobactam and imipenem reduced spleen ATCC 25922 strain concentrations (-2.53 and -2.14 log10 CFU/g [P < 0.05, respectively]) in the HI versus LI groups, while amoxicillin-clavulanate maintained its efficacy (-1.01 log10 CFU/g [no statistically significant difference]). Regarding the Ec1062 strain, the antimicrobials showed lower efficacy in the HI than in the LI groups: -0.73, -1.89, and -1.62 log10 CFU/g (P < 0.05, for piperacillin-tazobactam, imipenem, and amoxicillin-clavulanate, respectively, although imipenem and amoxicillin-clavulanate were more efficacious than piperacillin-tazobactam). An adapted imipenem treatment (based on the time for which the serum drug concentration remained above the MIC obtained with a HI of the ATCC 25922 strain) improved its efficacy to -1.67 log10 CFU/g (P < 0.05). These results suggest that amoxicillin

  19. Inoculum Effect on the Efficacies of Amoxicillin-Clavulanate, Piperacillin-Tazobactam, and Imipenem against Extended-Spectrum β-Lactamase (ESBL)-Producing and Non-ESBL-Producing Escherichia coli in an Experimental Murine Sepsis Model

    PubMed Central

    López-Cerero, L.; López-Rojas, R.; Egea, P.; Domínguez-Herrera, J.; Rodríguez-Baño, J.; Pascual, A.; Pachón, J.

    2013-01-01

    Escherichia coli is commonly involved in infections with a heavy bacterial burden. Piperacillin-tazobactam and carbapenems are among the recommended empirical treatments for health care-associated complicated intra-abdominal infections. In contrast to amoxicillin-clavulanate, both have reduced in vitro activity in the presence of high concentrations of extended-spectrum β-lactamase (ESBL)-producing and non-ESBL-producing E. coli bacteria. Our goal was to compare the efficacy of these antimicrobials against different concentrations of two clinical E. coli strains, one an ESBL-producer and the other a non-ESBL-producer, in a murine sepsis model. An experimental sepsis model {∼5.5 log10 CFU/g [low inoculum concentration (LI)] or ∼7.5 log10 CFU/g [high inoculum concentration (HI)]} using E. coli strains ATCC 25922 (non-ESBL producer) and Ec1062 (CTX-M-14 producer), which are susceptible to the three antimicrobials, was used. Amoxicillin-clavulanate (50/12.5 mg/kg given intramuscularly [i.m.]), piperacillin-tazobactam (25/3.125 mg/kg given intraperitoneally [i.p.]), and imipenem (30 mg/kg i.m.) were used. Piperacillin-tazobactam and imipenem reduced spleen ATCC 25922 strain concentrations (−2.53 and −2.14 log10 CFU/g [P < 0.05, respectively]) in the HI versus LI groups, while amoxicillin-clavulanate maintained its efficacy (−1.01 log10 CFU/g [no statistically significant difference]). Regarding the Ec1062 strain, the antimicrobials showed lower efficacy in the HI than in the LI groups: −0.73, −1.89, and −1.62 log10 CFU/g (P < 0.05, for piperacillin-tazobactam, imipenem, and amoxicillin-clavulanate, respectively, although imipenem and amoxicillin-clavulanate were more efficacious than piperacillin-tazobactam). An adapted imipenem treatment (based on the time for which the serum drug concentration remained above the MIC obtained with a HI of the ATCC 25922 strain) improved its efficacy to −1.67 log10 CFU/g (P < 0.05). These results suggest that

  20. Comparison of piperacillin/tazobactam and imipenem/cilastatin, both in combination with tobramycin, administered every 6 h for treatment of nosocomial pneumonia.

    PubMed

    Joshi, Manjari; Metzler, Michael; McCarthy, Mary; Olvey, Stephen; Kassira, Wedad; Cooper, Angel

    2006-09-01

    This randomized, double-blind, multicenter study compared the efficacy and safety of piperacillin/tazobactam (P/T) and imipenem/cilastatin (IMP), both in combination with an aminoglycoside, in hospitalized patients with acute nosocomial pneumonia (NP). Patients with acute NP, defined as pneumonia with symptoms > or = 48 h after admission or < or =7 days after hospital discharge, received infusions of 4 g/500 mg P/T or 500 mg/500 mg IMP every 6 h. Endpoints were clinical cure and microbiological response rates; pathogen eradication rates; length of hospital stay; hospital readmissions; and adverse events (AEs). Of 437 patients in the intent-to-treat population, 197 were efficacy evaluable. At test-of-cure, response rates were similar between groups. Within the efficacy evaluable population, 68% of P/T patients and 61% of IMP patients were clinically cured (P = 0.256). Microbiological responses for P/T and IMP patients were: eradication, 64% versus 59%; persistence, 29% versus 21%; relapse, 0% versus 5%; and superinfection, 7% versus 15%, respectively. Gram-positive isolates were eradicated in 83% of P/T patients and 75% of IMP patients; Gram-negative pathogens were eradicated in 72% of P/T patients and 77% of IMP patients. Treatment groups had similar number of mean hospital days, readmission rates, and frequency of AEs. This study showed that P/T administered four times per day was as safe and efficacious as IMP in treating hospitalized patients with NP.

  1. Molecular epidemiology of an outbreak of imipenem-resistant Acinetobacter baumannii carrying the ISAba1-bla(OXA-51-like) genes in a Korean hospital.

    PubMed

    Chaulagain, Bidur Prasad; Jang, Sook Jin; Ahn, Gyuu Yeol; Ryu, So Yeon; Kim, Dong Min; Park, Geon; Kim, Won Yong; Shin, Jong Hee; Kook, Joong Ki; Kang, Seong-Ho; Moon, Dae Soo; Park, Young Jin

    2012-01-01

    Between January 2004 and December 2004, an outbreak of imipenem-resistant Acinetobacter baumannii (IRAB) in 2 intensive care units (ICU) of Chosun University Hospital, Korea affected 77 patients. A case-control study revealed that the time spent in the hospital and mechanical ventilation practices were risk factors. IRAB was isolated from the hands of 4% (5/124) of healthcare workers; 27.3% (21/77) of the samples obtained from the ICU environment. A pulsed-field gel electrophoresis analysis showed that 82.1% (23/28) of clinical IRAB isolates and 85.7% (6/7) of environmental IRAB isolates were type A. The ISAba1F/OXA-51-likeR PCR showed that 93.7% (30/32) of IRAB strains had the ISAba1 gene upstream of the bla(OXA-51-like) gene. Two ISAba1F/OXA-51-likeR PCR-negative IRAB strains were bla(IMP-1) positive. All of the IRAB strains tested by PCR were negative for bla(VIM), bla(SIM), bla(GIM-1), bla(SPM-1), bla(GES), bla(OXA-23-like), bla(OXA-24-like), and bla(OXA-58-like) carbapenemase genes. After implementing an infection control strategy, a steady reduction in the attack rate of IRAB infection was observed.

  2. Activity of Moxifloxacin, Imipenem, and Ertapenem against Escherichia coli, Enterobacter cloacae, Enterococcus faecalis, and Bacteroides fragilis in Monocultures and Mixed Cultures in an In Vitro Pharmacokinetic/Pharmacodynamic Model Simulating Concentrations in the Human Pancreas

    PubMed Central

    Schubert, Sabine

    2012-01-01

    The activities of moxifloxacin, imipenem, and ertapenem against pathogens causing severe necrotizing pancreatitis were studied in an in vitro pharmacokinetics/pharmacodynamics (PK/PD) model. Escherichia coli, Enterobacter cloacae, Enterococcus faecalis, and Bacteroides fragilis were exposed in monocultures and mixed cultures to concentrations of the three agents comparable to those in the human pancreas. Moxifloxacin was more active than the two carbapenems in monocultures and mixed cultures, reducing the numbers of CFU more drastically and more rapidly. PMID:23070164

  3. ISPa46, a novel insertion sequence in the oprD porin gene of an imipenem-resistant Pseudomonas aeruginosa isolate from a cystic fibrosis patient in Marseille, France.

    PubMed

    Diene, Seydina M; L'homme, Tiphanie; Bellulo, Sophia; Stremler, Nathalie; Dubus, Jean-Christophe; Mely, Laurent; Leroy, Sylvie; Degand, Nicolas; Rolain, Jean-Marc

    2013-09-01

    Clinical isolates of Pseudomonas aeruginosa exhibiting high-level resistance to carbapenems were recovered from a French patient with cystic fibrosis (CF) who had not received carbapenem therapy. This study was conducted to investigate the molecular mechanism conferring the carbapenem-resistant phenotype in clinical isolates of P. aeruginosa recovered from the same CF patient chronically colonised since 2005. Investigation of imipenem resistance of P. aeruginosa strain_02 isolated in May 2011 showed no carbapenemase activity. However, amplification and sequencing of the oprD porin gene revealed disruption of this gene by an insertion sequence (IS) element of 1337 bp that contained a novel transposase of 1227 bp (ISPa46) bordered by two terminal imperfect inverted repeats of 28 bp, which was associated with carbapenem resistance. Retrospective analysis of five additional strains of P. aeruginosa isolated before May 2011 from the same patient revealed that all isolates were likely to be the same clone by multilocus sequence typing analysis (ST540/551), but one of the five isolates was imipenem-susceptible. Although it was possible to demonstrate the presence of ISPa46 in all strains by PCR, this IS was transposed in the oprD gene only for imipenem-resistant isolates. Therefore, this study reports a novel IS element (ISPa46) in P. aeruginosa clinical isolates of a CF patient in Marseille, France, that was associated with carbapenem resistance and was selected in the absence of carbapenem treatment.

  4. Optimisation of imipenem regimens in patients with impaired renal function by pharmacokinetic-pharmacodynamic target attainment analysis of plasma and urinary concentration data.

    PubMed

    Yoshizawa, Kenichi; Ikawa, Kazuro; Ikeda, Kayo; Kumon, Hiromi; Ohge, Hiroki; Morikawa, Norifumi

    2012-11-01

    In this study, a pharmacokinetic-pharmacodynamic (PK-PD) target attainment analysis of imipenem (IPM) in patients with impaired renal function was conducted. IPM (500 mg) was administered via a 0.5-h or 1-h infusion to 27 patients with varying renal function. A population PK model was developed by simultaneously fitting plasma and urinary concentration data. A two-compartment model adequately described IPM pharmacokinetics, and creatinine clearance (CL(Cr)) was identified as the most significant covariate. A PK-PD simulation predicted the probabilities of attaining the target in plasma [40% of the time above the minimum inhibitory concentration (MIC)] and defined the PK-PD breakpoints (the highest MICs at which the probabilities were ≥90%). In a patient with a CL(Cr) of 90 mL/min, prolongation of infusion time (from 0.5 h to 1.5 h) increased the PK-PD breakpoint from 1 μg/mL to 2 μg/mL with a 500 mg dose every 8h (q8h) and from 2 μg/mL to 4 μg/mL with a 500 mg dose every 6h (q6h). Meanwhile, in a patient with a CL(Cr) of 20 mL/min, the PK-PD breakpoints for both 0.5-h and 1.5-h infusions were 1 μg/mL with a 250 mg dose every 12h (q12h), 2 μg/mL with a 250 mg dose q8h and a 500 mg dose q12h, and 4 μg/mL with a 250 mg dose q6h. These results indicate that a shorter dosing interval is beneficial in patients with impaired renal function as it results in greater PK-PD breakpoints and a reduction in excessive maximum plasma concentrations. These results help to optimise IPM regimens, particularly in patients with impaired renal function.

  5. Efflux Pump Inhibitor Phenylalanine-Arginine Β-Naphthylamide Effect on the Minimum Inhibitory Concentration of Imipenem in Acinetobacter baumannii Strains Isolated From Hospitalized Patients in Shahid Motahari Burn Hospital, Tehran, Iran

    PubMed Central

    Gholami, Mehrdad; Hashemi, Ali; Hakemi-Vala, Mojdeh; Goudarzi, Hossein; Hallajzadeh, Masoumeh

    2015-01-01

    Background: Acinetobacter baumannii has emerged as a highly troublesome pathogen and a leading cause of mortality and morbidity among hospitalized burn patients. Objectives: The aims of this study were to determine the frequency of the AdeABC genes and the role of the efflux pump (s) in the imipenem resistance of A. baumannii strains isolated from burn patients. Materials and Methods: This study was conducted on 60 A. baumannii isolates collected from 240 wound samples of burn patients admitted to the Burn Unit of Shahid Motahari Burn hospital, Tehran, Iran. Antibiotic susceptibility tests were performed using the Kirby-Bauer disc diffusion and broth microdilution according to the clinical and laboratory standards institute (CLSI) guidelines. The activity of the efflux pump was evaluated using the efflux pump inhibitor, the phenylalanine-arginine Β-naphthylamide (PAΒN). The AdeABC genes were detected by polymerase chain reaction (PCR) and sequencing. Results: In this study, 100% of the isolates were resistant to cefotaxime, ceftazidime, ceftriaxone, ciprofloxacin, cefepime, piperacillin, meropenem, co-trimoxazole, and piperacillin/tazobactam; 56 (94%) to gentamicin; 50 (81%) to amikacin; 58 (97%) to imipenem; and 45 (76%) to tetracycline. Additionally,all the isolates were susceptible to colistin. The susceptibility of the strains to imipenem was highly increased in the presence of the efflux pump inhibitor such that for 58 (96.6%) of the isolates, the PAΒN reduced the minimum inhibitory concentrations (MIC) by 4- to 64-fold. The adeA and adeB genes were detected in 60 (100%) of the isolates, and the adeC gene was present in 51 (85%). Conclusions: The efflux pump may play a role in antibiotic resistance in A. baumannii isolates. The ability of A. baumannii isolates to acquire drug resistance by the efflux pump mechanism is a concern. Thus, new strategies are required in order to eliminate the efflux transport activity from resistant A. baumannii isolates causing

  6. In Vitro Activity of ACH-702, a New Isothiazoloquinolone, against Nocardia brasiliensis Compared with Econazole and the Carbapenems Imipenem and Meropenem Alone or in Combination with Clavulanic Acid ▿

    PubMed Central

    Vera-Cabrera, Lucio; Campos-Rivera, Mayra Paola; Escalante-Fuentes, Wendy G.; Pucci, Michael J.; Ocampo-Candiani, Jorge; Welsh, Oliverio

    2010-01-01

    The in vitro activities of ACH-702 and other antimicrobials against 30 Nocardia brasiliensis isolates were tested. The MIC50 (MIC for 50% of the strains tested) and MIC90 values of ACH-702 were 0.125 and 0.5 μg/ml. The same values for econazole were 2 and 4 μg/ml. The MIC50 and MIC90 values of imipenem and meropenem were 64 and >64 μg/ml and 2 and 8 μg/ml, respectively; the addition of clavulanic acid to the carbapenems had no effect. PMID:20308390

  7. Imipenem-avibactam: a novel combination for the rapid detection of carbapenemase activity in Enterobacteriaceae and Acinetobacter baumannii by matrix-assisted laser desorption ionization-time of flight mass spectrometry.

    PubMed

    Oviaño, Marina; Bou, Germán

    2017-02-01

    In the present study, we propose a novel matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)-based method for detecting carbapenemase-producing Enterobacteriaceae and Acinetobacter baumannii. For this, we analyzed a series of 131 isolates. Among them, a total of 115 Enterobacteriaceae: 79 of them carrying a carbapenemase enzyme (15blaKPC, 7blaNDM, 11blaIMP, 12blaVIM, and 34blaOXA-48) and 16 A. baumannii isolates: 15 of them carrying carbapenemases (10blaOXA-23, 2blaOXA-58, 2blaOXA-24, and 1blaOXA-237). The rest of the isolates were noncarbapenemase producers and used as negative controls. The isolates were submitted to susceptibility testing using a combination of imipenem-avibactam and analysis by the MALDI-TOF Biotyper Compass software (Bruker Daltonik, Germany). The assay showed an overall sensitivity and specificity for carbapenemase detection of 98% and 100%, respectively. The combination of imipenem and avibactam displayed activity against KPC and OXA-48-producing Enterobacteriaceae and thus represents a new strategy for identifying and confirming these carbapenemases. However, the combination did not provide any benefit over A. baumannii.

  8. Interspecies scaling of excretory amounts using allometry - retrospective analysis with rifapentine, aztreonam, carumonam, pefloxacin, miloxacin, trovafloxacin, doripenem, imipenem, cefozopran, ceftazidime, linezolid for urinary excretion and rifapentine, cabotegravir, and dolutegravir for fecal excretion.

    PubMed

    Srinivas, Nuggehally R

    2016-09-01

    1. Interspecies allometry scaling for prediction of human excretory amounts in urine or feces was performed for numerous antibacterials. Antibacterials used for urinary scaling were: rifapentine, pefloxacin, trovafloxacin (Gr1/low; <10%); miloxacin, linezolid, PNU-142300 (Gr2/medium; 10-40%); aztreonam, carumonam, cefozopran, doripenem, imipenem, and ceftazidime (Gr3/high; >50%). Rifapentine, cabotegravir, and dolutegravir was used for fecal scaling (high; >50%). 2. The employment of allometry equation: Y = aW(b) enabled scaling of urine/fecal amounts from animal species. Corresponding predicted amounts were converted into % recovery by considering the respective human dose. Comparison of predicted/observed values enabled fold difference and error calculations (mean absolute error [MAE] and root mean square error [RMSE]). Comparisons were made for urinary/fecal data; and qualitative assessment was made amongst Gr1/Gr2/Gr3 for urine. 3. Average correlation coefficient for the allometry scaling was >0.995. Excretory amount predictions were largely within 0.75- to 1.5-fold differences. Average MAE and RMSE were within ±22% and 23%, respectively. Although robust predictions were achieved for higher urinary/fecal excretion (>50%), interspecies scaling was applicable for low/medium excretory drugs. 4. Based on the data, interspecies scaling of urine or fecal excretory amounts may be potentially used as a tool to understand the significance of either urinary or fecal routes of elimination in humans in early development.

  9. Real-time video imaging as a new and rapid tool for antibiotic susceptibility testing by the disc diffusion method: a paradigm for evaluating resistance to imipenem and identifying extended-spectrum β-lactamases.

    PubMed

    Le Page, Stéphanie; Raoult, Didier; Rolain, Jean-Marc

    2015-01-01

    The disc diffusion method has long been considered the standard technique for antibiotic susceptibility testing (AST) in clinical microbiology laboratories because of its simplicity, reproducibility and low cost compared with commercial automated microdilution systems that are usually more rapid but less sensitive for detecting important mechanisms of resistance. Here we measured reading zone diameters around antibiotics in a series of 25 well-characterised Gram-negative bacteria by the disc diffusion technique in real-time using an Advencis Bio-System instrument consisting of a real-time high-resolution video imager in a dedicated incubator. The susceptibility of wild-type Gram-negative bacteria to imipenem, determined by reading the diameter of inhibition, was detectable as early as 3.5h (mean time 3.7 ± 0.45 h), whereas carbapenemase-producing Gram-negative bacteria could be correctly categorised as early as 3h (mean time 4.2 ± 0.8 h) of incubation. Similarly, the characteristic champagne cork aspect of extended-spectrum β-lactamase (ESBL) could be detected by the system as early as 3.5 h. Moreover, we present here for the first time video movies of the appearance of the diameter of inhibition by disc diffusion in real-time. This preliminary study using a new and innovative technology provides for a renewed interest for microbiologists who wish to continue to use the disc diffusion method as a reference method for AST. New video imaging technology presents a proof of concept that could improve the real-time management of patients with AST within a very rapid turnaround time and can provide a large financial saving for hospitals.

  10. Resistance to imipenem, cefepime, and cefpirome associated with mutation in Omp36 osmoporin of Enterobacter aerogenes.

    PubMed

    Thiolas, Aurélie; Bornet, Charléric; Davin-Régli, Anne; Pagès, Jean-Marie; Bollet, Claude

    2004-05-07

    Enterobacter aerogenes develops increased multidrug resistance via a functional alteration of outer-membrane permeability associated with a decrease in porin function. We have sequenced the gene coding the major porin of Enterobacter aerogenes, omp36. The sequence shows a high similarity with the Klebsiella pneumoniae ompK36 gene and is closely related to the enterobacterial OmpC family. Sequence analysis of several Omp36 issued from clinical strains indicated variability in putative cell-surface exposed domains. Interestingly, substitution Gly112Asp was observed in the conserved eyelet L3 region of the porin produced by two strains, C and 3. This substitution is associated with a high general beta-lactam resistance observed in these isolates and with alteration of pore properties previously described in strain 3 porin [Mol. Microbiol. 41 (2001) 189]. This is the first genetic identification of impermeability-mediated resistance to beta-lactams in various clinical E. aerogenes strains.

  11. Activity of Imipenem against Klebsiella pneumoniae Biofilms In Vitro and In Vivo

    DTIC Science & Technology

    2014-02-01

    investigated different categories of compounds for a potential biofilm-disrupting agent(s). Compounds included antibiotics, quorum - sensing inhibitors...effect No change Dispersin B 100 No effect No change cis-2-Decenoic acid 500 No effect No change Quorum - sensing inhibitors F-219 500 2 Lots of dead

  12. [Phenotypic and genotypic characterization of imipenem-resistant Pseudomonas aeruginosa isolated in a Buenos Aires hospital].

    PubMed

    Cejas, D; Almuzara, M; Santella, G; Tuduri, A; Palombarani, S; Figueroa, S; Gutkind, G; Radice, M

    2008-01-01

    From 129 P. aeruginosa isolated at a health care centre located in Buenos Aires (Hospital "Eva Perón"), 14% produced IMP-13. Although 18 isolates were metallo-beta-lactamases (MBL) producers, only those isolates that displayed altered outer membrane protein profiles correlated with the resistant category according to CLSI or even Subcomisión de Antimicrobianos, SADEBAC, AAM. Phenotypic screening of metallo-beta-lactamases proved to be appropriate for detecting MBL producing isolates. IMP-13 producing isolates corresponded to at least five different clonal types, which not only suggests the dissemination of the resistant strain but also of the resistant marker.

  13. Long-Term outcome of neonatal Citrobacter koseri (diversus) meningitis treated with imipenem/meropenem and surgical drainage.

    PubMed

    Straussberg, R; Harel, L; Amir, J

    2001-10-01

    Neonatal Citrobacter koseri (diversus) meningitis is often complicated by the formation of brain abscesses and has a poor neurological outcome with seizures, mental retardation and paresis as sequelae in 50% of the cases. As there is emerging resistance to ampicillin, gentamicin and third-generation cephalosporins, we attempted to treat this infection with carbapenems. Carbapenems in combination with cefotaxime and surgical drainage may play an important role in treating C. koseri meningitis.

  14. Biochemical properties of beta-lactamase produced by Legionella gormanii.

    PubMed Central

    Fujii, T; Sato, K; Miyata, K; Inoue, M; Mitsuhashi, S

    1986-01-01

    beta-Lactamase was purified from a strain of Legionella gormanii. The molecular weight of the purified enzyme was 25,000, and its isoelectric point was 10.5. The enzyme hydrolyzed oxyiminocephalosporins, cephamycins, penicillins, and imipenem. The enzyme activity was inhibited by EDTA, Hg2+, and Cu2+, but not by clavulanic acid, sulbactam, or imipenem. PMID:3488020

  15. Stability of meropenem and effect of 1 beta-methyl substitution on its stability in the presence of renal dehydropeptidase I.

    PubMed Central

    Fukasawa, M; Sumita, Y; Harabe, E T; Tanio, T; Nouda, H; Kohzuki, T; Okuda, T; Matsumura, H; Sunagawa, M

    1992-01-01

    The stability of meropenem in the presence of renal dehydropeptidase I (DHP-I) varied extremely with the animal source of the enzyme. Meropenem, compared with imipenem, was rather easily hydrolyzed by DHP-Is from mice, rabbits, and monkeys, while it showed a higher resistance to guinea pig and beagle dog DHP-Is. In addition, meropenem was four times more resistant than imipenem to human DHP-I. The 1 beta-methyl substituent on carbapenems, i.e., meropenem and 1 beta-methyl imipenem, made them considerably more resistant to mouse and swine DHP-Is than the 1-unsubstituted derivatives are. PMID:1510457

  16. Doripenem Injection

    MedlinePlus

    ... such as imipenem/cilastatin (Primaxin) or meropenem (Merrem); penicillins; cephalosporin antibiotics such as cefaclor, cefadroxil, cefuroxime (Ceftin, ... effects.tell your doctor if you have any allergies and if you have or have ever had ...

  17. Widespread of ESBL- and carbapenemase GES-type genes on carbapenem-resistant Pseudomonas aeruginosa clinical isolates: a multicenter study in Mexican hospitals.

    PubMed

    Garza-Ramos, Ulises; Barrios, Humberto; Reyna-Flores, Fernando; Tamayo-Legorreta, Elsa; Catalan-Najera, Juan C; Morfin-Otero, Rayo; Rodríguez-Noriega, Eduardo; Volkow, Patricia; Cornejo-Juarez, Patricia; González, Alejandra; Gaytan-Martinez, Jesus; Del Rocío Gónzalez-Martínez, Marisela; Vazquez-Farias, Maria; Silva-Sanchez, Jesus

    2015-02-01

    The present work describes a prevalence of 36.2% of carbapenemases IMP-, VIM-, and GES-type on 124 imipenem-resistant Pseudomonas aeruginosa clinical isolates. The ESBL GES-19 and carbapenemase GES-20 genes were the most prevalent (84.4%) β-lactamases among imipenem-resistant P. aeruginosa clinical isolates in Mexico. These genes are chromosomal encoded on embedded class 1 integron arrays.

  18. In vitro activities of antimicrobial agents, alone and in combination, against Acinetobacter baumannii isolated from blood.

    PubMed

    Chang, S C; Chen, Y C; Luh, K T; Hsieh, W C

    1995-11-01

    In vitro activities of 15 antimicrobial agents against 90 strains of Acinetobacter baumannii isolated from blood cultures from hospitalized patients were determined using the agar dilution method. Imipenem, ofloxacin, and ciprofloxacin had the best antimicrobial activity with minimum inhibitory concentrations (MIC50s) of 0.25 mu g/ml and MIC90s of 0.5-1 mu g/ml. beta-lactam antibiotics other than imipenem had poor activity, with MIC50s ranging from 8 to 64 mu g/ml and MIC90s from 32 to > or = 256 mu g/ml. The checkerboard titration method was used to study the effects of combination of two antimicrobial agents. Combinations of ceftazidime, aztreonam, imipenem, or ciprofloxacin with amikacin showed either synergistic effects or partial synergistic effects for 40.9%-86.4% of 22 tested strains. The best in vitro activity was observed with the combination of imipenem and amikacin. No antagonistic effects were observed with the combination of imipenem and amikacin. Synergistic effects were confirmed by time-kill curve studies. In conclusion, imipenem, ofloxacin, and ciprofloxacin were the three most active agents against human blood isolates of A. baumannii. The combination of a beta-lactam or ciprofloxacin with amikacin was synergistic for some of the isolates.

  19. [In vitro activities of sulopenem, a new parenteral penem, against anaerobes].

    PubMed

    Watanabe, K; Kato, N; Tanaka-Bandoh, K; Tanaka, Y; Kato, H; Ueno, K

    1996-04-01

    In vitro activities of sulopenem, a novel parenteral penem, was compared with those of imipenem, flomoxef, cefuzonam, cefoperazone and sulbactam/ampicillin against 66 reference strains (19 genera, 61 species) and 392 recent clinical isolates of anaerobic bacteria and fastidious aerobic bacteria. Sulopenem had a very broad spectrum against anaerobic bacteria. In general, this compound was active against anaerobic reference strains with MICs of < or = 0.78 micrograms/ml, while being the least active against Bifidobacterium spp. and less active than imipenem against Lactobacillus spp. Sulopenem was more active against Bacteroides fragilis isolates than imipenem and had the highest activities against Bacteroides thetaiotaomicron, Prevotella intermedia, Porphyromonas gingivalis, Fusobacterium spp. and Peptostreptococcus spp. among the antibiotics tested. Sulopenem was not hydrolyzed by oxyiminocephalosporinase type 1 produced by B. fragilis GAI-0558, GAI-7955 and GAI-10150 and its stability was comparable to imipenem. Its susceptibilities to hydrolysis by a metallo-beta-lactamase from B. fragilis GAI-30144 was less than imipenem. Sulopenem (120 mg/kg, 3 times a day for 4 days) was as effective as imipenem/cilastatin against a mixed intraabdominal mice infection due to E. coli and B. fragilis. Sulopenem (20 mg/kg twice a day for 5 days) did not induce an overgrowth of Clostridium difficile in the caecum of mice.

  20. Carbapenem resistance in a clinical isolate of Enterobacter aerogenes is associated with decreased expression of OmpF and OmpC porin analogs.

    PubMed

    Yigit, Hesna; Anderson, Gregory J; Biddle, James W; Steward, Christine D; Rasheed, J Kamile; Valera, Lourdes L; McGowan, John E; Tenover, Fred C

    2002-12-01

    We investigated the mechanism of imipenem resistance in Enterobacter aerogenes strain 810, a clinical isolate from the United States for which the imipenem MIC was 16 micro g/ml and the meropenem MIC was 8 micro g/ml. An imipenem-susceptible revertant, strain 810-REV, was obtained after multiple passages of the strain on nonselective media. For the revertant, the imipenem MIC was /=128 micro g/ml), cefoxitin (>/=32 micro g/ml), and cefotaxime (>/=64 micro g/ml) remained the same. The beta-lactamase and porin profiles of the parent, the revertant, and carbapenem-susceptible type strain E. aerogenes ATCC 13048 were determined. Strains 810 and 810-REV each produced two beta-lactamases with pIs of 8.2 and 5.4. The beta-lactamase activities of the parent and revertant were similar, even after induction with subinhibitory concentrations of imipenem. While 810-REV produced two major outer membrane proteins of 42 and 39 kDa that corresponded to Escherichia coli porins OmpC and OmpF, respectively, the parent strain appeared to produce similar quantities of the 39-kDa protein (OmpF) but decreased amounts of the 42-kDa protein (OmpC). When the parent strain was grown in the presence of imipenem, the 42-kDa protein was not detectable by gel electrophoresis. However, Western blot analysis of the outer membrane proteins of the parent and revertant with polyclonal antisera raised to the OmpC and OmpF analogs of Klebsiella pneumoniae (anti-OmpK36 and anti-OmpK35, respectively) showed that strain 810 expressed only the 42-kDa OmpC analog in the absence of imipenem (the 39-kDa protein was not recognized by the anti-OmpF antisera) and neither the OmpC nor the OmpF analog in the presence of imipenem. The OmpC analog is apparently down-regulated in the presence of imipenem; however, 810-REV expressed both OmpC and OmpF analogs. These data

  1. Rapid Induction of High-Level Carbapenem Resistance in Heteroresistant KPC-Producing Klebsiella pneumoniae

    PubMed Central

    Adams-Sapper, Sheila; Nolen, Shantell; Donzelli, Grace Fox; Lal, Mallika; Chen, Kunihiko; Justo da Silva, Livia Helena; Moreira, Beatriz M.

    2015-01-01

    Enterobacteriaceae strains producing the Klebsiella pneumoniae carbapenemase (KPC) have disseminated worldwide, causing an urgent threat to public health. KPC-producing strains often exhibit low-level carbapenem resistance, which may be missed by automated clinical detection systems. In this study, eight Klebsiella pneumoniae strains with heterogeneous resistance to imipenem were used to elucidate the factors leading from imipenem susceptibility to high-level resistance as defined by clinical laboratory testing standards. Time-kill analysis with an inoculum as low as 3 × 106 CFU/ml and concentrations of imipenem 8- and 16-fold higher than the MIC resulted in the initial killing of 99.9% of the population. However, full recovery of the population occurred by 20 h of incubation in the same drug concentrations. Population profiles showed that recovery was mediated by a heteroresistant subpopulation at a frequency of 2 × 10−7 to 3 × 10−6. Samples selected 2 h after exposure to imipenem were as susceptible as the unexposed parental strain and produced the major outer membrane porin OmpK36. However, between 4 to 8 h after exposure, OmpK36 became absent, and the imipenem MIC increased at least 32-fold. Individual colonies isolated from cultures after 20 h of exposure revealed both susceptible and resistant subpopulations. Once induced, however, the high-level imipenem resistance was maintained, and OmpK36 remained unexpressed even without continued carbapenem exposure. This study demonstrates the essential coordination between blaKPC and ompK36 expression mediating high-level imipenem resistance from a population of bacteria that initially exhibits a carbapenem-susceptibility phenotype. PMID:25801565

  2. Carbapenem susceptibilities and non-susceptibility concordance to different carbapenems amongst clinically important Gram-negative bacteria isolated from intensive care units in Taiwan: results from the Surveillance of Multicentre Antimicrobial Resistance in Taiwan (SMART) in 2009.

    PubMed

    Jean, Shio-Shin; Hsueh, Po-Ren; Lee, Wen-Sen; Yu, Kwok-Woon; Liao, Chun-Hsing; Chang, Feng-Yi; Ko, Wen-Chien; Wu, Jiunn-Jong; Chen, Yen-Hsu; Chen, Yao-Shen; Liu, Jien-Wei; Lu, Min-Chi; Liu, Cheng-Yi; Lam, Carlos; Chen, Ray-Jade

    2013-05-01

    To investigate the in vitro susceptibilities to various carbapenems amongst clinical Gram-negative bacteria isolated from patients in intensive care units of ten major teaching hospitals in Taiwan in 2009, a survey was conducted to determine the minimum inhibitory concentrations (MICs) of ertapenem, imipenem, meropenem and doripenem against isolates of Enterobacteriaceae (n = 594), Pseudomonas aeruginosa (n = 185), Acinetobacter baumannii (n = 192) and Burkholderia cepacia (n = 23) using the agar dilution method. Susceptibilities were determined according to 2009, 2011 and 2012 MIC breakpoints recommended by the CLSI as well as 2012 MIC breakpoints recommended by EUCAST. Based on CLSI 2012 criteria, the ertapenem susceptible rate was 93%, 81%, 68% and 92% for Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae and Serratia marcescens, respectively. All Proteus mirabilis and Morganella morganii isolates were susceptible to ertapenem; however, 64% of P. mirabilis and all M. morganii isolates were non-susceptible to imipenem. Meropenem and doripenem had better activities than imipenem against ertapenem-non-susceptible Enterobacteriaceae isolates. E. coli, K. pneumoniae and E. cloacae with ertapenem MICs≥4 mg/L were synchronously not susceptible to imipenem, meropenem and doripenem. Imipenem susceptibility was 65% and 29% for P. aeruginosa and A. baumannii, respectively. Additionally, P. aeruginosa and A. baumannii isolates with imipenem MICs≥8 mg/L were also not susceptible to meropenem and doripenem. These data provide a better understanding of choosing appropriate carbapenem agents to treat infections caused by ertapenem-non-susceptible Enterobacteriaceae as well as P. aeruginosa and A. baumannii isolates with imipenem MICs≥4 mg/L.

  3. [Antimicrobial activity of ornidazole and 6 other antibiotics against anaerobic bacteria].

    PubMed

    Alados, J C; Martínez-Brocal, A; Miranda, C; Rojo, M D; García, V; Domínguez, M C; de la Rosa, M

    1991-04-01

    The antimicrobial susceptibility of 235 anaerobic bacterial strains to ornidazole, metronidazole, chloramphenicol, clindamycin, penicillin, cefoxitin and imipenem has been studied using agar-dilution technique. Ornidazole and metronidazole were active against 88.6% and 86% of gram-positive cocci. Overall, 99.1% of Bacteroides group fragilis, and 91.3% of non-fragilis Bacteroides were also sensitive to both drugs. We did not find any Clostridium perfringens resistant strain. Cefoxitin and penicillin showed good activity against all Clostridium perfringens strains, and also against 97.7% and 92.5% of gram-positive cocci. We found one single imipenem resistant strain among gram-positive bacteria. Bacteroides fragilis also showed sensitivity to penicillin (41.5%), cefoxitin (85.7%) and imipenem (97.1%). Clindamycin was active against Clostridium perfringens (90.9%), gram-positive cocci (86.7%) and imipenem (68.6%). Chloramphenicol showed good activity against Clostridium perfringens (100%), gram-positive cocci (95.5%) and Bacteroides spp. (99.4%). Our results showed an overall good activity of all the seven drugs tested against anaerobic gram-positive microorganisms. Of notice, we found a good activity of chloramphenicol, imipenem, metronidazole and ornidazole against Bacteroides spp.

  4. Molecular Docking and Molecular Dynamics Studies to Identify Potential OXA-10 Extended Spectrum β-Lactamase Non-hydrolysing Inhibitors for Pseudomonas aeruginosa.

    PubMed

    Malathi, Kullappan; Ramaiah, Sudha

    2016-06-01

    Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic bacterium that frequently causes nosocomial infections. New generation cephalosporins and β-lactams along with inhibitors are used for the treatment of opportunistic bacterial infections. The indiscriminate use of antibiotics has led to the emergence of bacterial resistance. Carbapenem class of antibiotics like imipenem and meropenem are currently the final line of antibiotics for the treatment of infections caused by multidrug-resistant P. aeruginosa. Recent reports indicate that P. aeruginosa has acquired resistance to imipenem through a class D oxacillinase-OXA-10 extended spectrum β-lactamase (ESBL). OXA-10 ESBL is encoded by the gene blaOXA-10. There is an urgent need to develop OXA-10 ESBL non-hydrolysing inhibitors. We have attempted to locate OXA-10 ESBL inhibitors by performing molecular docking and molecular dynamics studies on OXA-10 ESBL with imipenem analogues from ZINC database as well as employing imipenem to understand the mechanism of resistance at the structural level. Our in-silico analysis of imipenem analogues reveals that ZINC44672480 has ideal characteristics for a potent OXA-10 ESBL non-hydrolysing inhibitor. We believe that the results from our study will provide valuable insights into the mechanism of drug resistance and aid in designing potent inhibitors against OXA-10 ESBL producing P. aeruginosa.

  5. In vitro sensitivity of Acinetobacter baumannii and Pseudomonas aeruginosa to carbapenems among intensive care unit patients.

    PubMed

    Guzek, A; Korzeniewski, K; Nitsch-Osuch, Aneta; Rybicki, Z; Prokop, E

    2013-01-01

    Acinetobacter baumannii and Pseudomonas aeruginosa pathogens are the most common causes of fatal pneumonia among patients treated in Intensive Care Units (ICU). Carbapenems remain a group of antibiotics characterized by the highest effectiveness in treatment of heavy infections of the lower respiratory tract. This study compared in vitro sensitivity of A. baumannii and P. aeruginosa to three carbapenems: imipenem, meropenem and doripenem. The material was collected from 71 patients treated in the ICU from April 2009 to January 2010. Bronchial tree was the predominant source of samples. Fifty-four strains of A. baumannii and 17 strains of P. aeruginosa were analyzed. Sensitivity to carbapenems was interpreted in line with Clinical and Laboratory Standard Institute (CLSI) and European Committee for Antimicrobial Susceptibility Testing (EUCAST) criteria (imipenem and meropenem) or in compliance with the Food and Drug Administration (FDA) and CLSI guidelines (doripenem). We found that A. baumannii was significantly more often sensitive to imipenem than to doripenem and meropenem, but only according to the CLSI and FDA and not EUCAST criteria. The sensitivity of P. aeruginosa was higher to imipenem than to doripenem and meropenem, according to both CLSI and EUCAST criteria (64.7 %). We conclude that the EUCAST criteria demonstrate a higher rigor than those of CLSI and FDA in the determination of carbapenems sensitivity. Imipenem appears more effective than doripenem and meropenem in treatment of A. baumannii and P. aeruginosa infections.

  6. Cationic peptides combined with betalactams reduce mortality from peritonitis in experimental rat model.

    PubMed

    Ghiselli, Roberto; Giacometti, Andrea; Cirioni, Oscar; Mocchegiani, Federico; Viticchi, Claudio; Scalise, Giorgio; Saba, Vittorio

    2002-11-01

    The efficacy of cationic peptides combined with betalactams was investigated in a peritonitis rat model. Intraabdominal sepsis was induced in adult Wistar rats via cecal ligation and single puncture. The study included eight drug-treated groups: each of them received intravenous polymyxin-E (1 mg/kg), buforin II (1 mg/kg), imipenem (20 mg/kg), amoxicillin-clavulanate (50 mg/kg), polymyxin-E (1 mg/kg) plus imipenem (20 mg/kg), or amoxicillin-clavulanate (50 mg/kg), and buforin II (1 mg/kg) plus imipenem (20 mg/kg), or amoxicillin-clavulanate (50 mg/kg). The study included an untreated control group that received intravenous isotonic sodium chloride solution. All compounds significantly reduced the lethality and the number of bacteria in abdominal fluid compared with saline treatment. Among compounds, imipenem showed the highest antimicrobial activity, while buforin II produced the highest reduction in plasma endotoxin and TNF-alpha levels. Overall, buforin II and imipenem association were the most effective therapeutic approach. Data presented here suggest the potential advantages of combining antimicrobial agents and compounds able to neutralize the biological effect of the endotoxin.

  7. Antibiotic uptake through membrane channels: role of Providencia stuartii OmpPst1 porin in carbapenem resistance.

    PubMed

    Bajaj, Harsha; Tran, Que-Tien; Mahendran, Kozhinjampara R; Nasrallah, Chady; Colletier, Jacques-Phillippe; Davin-Regli, Anne; Bolla, Jean-Michel; Pagès, Jean-Marie; Winterhalter, Mathias

    2012-12-21

    The role of major porin OmpPst1 of Providencia stuartii in antibiotic susceptibility for two carbapenems is investigated by combining high-resolution conductance measurements, liposome swelling, and microbiological assays. Reconstitution of a single OmpPst1 into a planar lipid bilayer and measuring the ion current, in the presence of imipenem, revealed a concentration-dependent decrease in conductance, whereas meropenem produced well-resolved short ion current blockages. Liposome swelling assays suggested a small flux of imipenem in contrast to a rapid permeation of meropenem. The lower antibiotic susceptibility of P. stuartii to imipenem compared to meropenem correlated well with the decreased level of permeation of the former through the OmpPst1 channel.

  8. Membrane permeability, a pivotal function involved in antibiotic resistance and virulence in Enterobacter aerogenes clinical isolates.

    PubMed

    Lavigne, J-P; Sotto, A; Nicolas-Chanoine, M-H; Bouziges, N; Bourg, G; Davin-Regli, A; Pagès, J-M

    2012-06-01

    Imipenem-susceptible E. aerogenes isolates exhibiting extended spectrum β-lactamases, target mutations and a basal efflux expression, were identified in five patients. After imipenem treatment, imipenem-intermediate susceptible (IMI-I) or resistant (IMI-R) isolates emerged in these patients. Alteration in porin synthesis and increase in efflux expression were observed in the IMI-I isolates whereas complete loss of the porins, LPS alteration and efflux overexpression were observed in the IMI-R isolates. Bacterial virulence of the strains was investigated by the Caenorhabditis elegans model. The IMI-R isolates were shown to be significantly less virulent than the IMI-susceptible or IMI-I isolates. The pleiotropic membrane alteration and its associated fitness burden exhibited by E. aerogenes isolates influence their antibiotic resistance and their virulence behaviour. These findings highlight the balance between the low permeability-related resistance and virulence and their relationships with the treatment of resistant pathogens.

  9. [In vitro and in vivo antibacterial activities of sulopenem, a new penem antibiotic].

    PubMed

    Komoto, A; Otsuki, M; Nishino, T

    1996-04-01

    The in vitro and in vivo antibacterial activities of sulopenem, a new penem, were evaluated in comparison with imipenem (IPM), meropenem (MEPM), ceftazidime (CAZ) and flomoxef (FMOX). Sulopenem had broad and potent antibacterial spectra against Gram-positive and Gram-negative bacteria, including Enterococcus faecalis, Proteus vulgaris, Morganella morganii, Enterobacter spp. and Citrobacter freundii. Sulopenem showed concentration-dependent bactericidal activities against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Acinetobacter calcoaceticus. Morphological observation using phase-contrast microscope revealed that sulopenem induced spherical cell formation with E. coli and K. pneumoniae at lower concentrations and bacteriolysis at higher concentrations. Therapeutic efficacies of sulopenem against systemic infections in mice were almost equal to those of imipenem against Streptococcus pneumoniae. While its therapeutic efficacies were superior to those of meropenem, ceftazidime and flomoxef against S. aureus and S. pneumoniae, they were inferior to those of imipenem/cilastatin against S. aureus, K. pneumoniae and A. calcoaceticus.

  10. Acinetobacter sp. isolates from emergency departments in two hospitals of South Korea.

    PubMed

    Choi, Ji-Young; Ko, Eun Ah; Kwon, Ki Tae; Lee, Shinwon; Kang, Choel In; Chung, Doo-Ryeon; Peck, Kyong Ran; Song, Jae-Hoon; Ko, Kwan Soo

    2014-10-01

    A total of 114 Acinetobacter sp. isolates were collected from patients in the emergency departments (EDs) of two Korean hospitals. Most isolates belonged to the Acinetobacter baumannii complex (105 isolates, 92.1 %). Imipenem resistance was found in 39 isolates (34.2 %) of the Acinetobacter sp. isolates, and 6 colistin-resistant isolates were also identified. Species distribution and antimicrobial-resistance rates were different between the two hospitals. In addition, two main clones were identified in the imipenem-resistant A. baumannii isolates from hospital B, but very diverse and novel genotypes were found in those from hospital A. Many Acinetobacter sp. isolates, including the imipenem-resistant A. baumannii, are considered to be associated with the community. The evidence of high antimicrobial resistance and different features in these Acinetobacter sp. isolates between the two EDs suggests the need for continuous testing to monitor changes in epidemiology.

  11. Emergence of KPC-Possessing Klebsiella pneumoniae in Brooklyn, New York: Epidemiology and Recommendations for Detection

    PubMed Central

    Bratu, Simona; Mooty, Mohamad; Nichani, Satyen; Landman, David; Gullans, Carl; Pettinato, Barbara; Karumudi, Usha; Tolaney, Pooja; Quale, John

    2005-01-01

    Among 257 isolates of Klebsiella pneumoniae collected in Brooklyn, NY, 24% were found to possess blaKPC. Clinical microbiology laboratories that used automated broth microdilution systems reported 15% of the KPC-possessing isolates as susceptible to imipenem. The imipenem MIC was found to be markedly affected by the inoculum. For accurate detection of KPC-possessing K. pneumoniae, particular attention should be paid to proper inoculum preparation for broth-based susceptibility methods. In addition, using ertapenem or meropenem for class reporting of carbapenem susceptibility will improve detection. PMID:15980389

  12. Efficacy of Lysophosphatidylcholine in Combination with Antimicrobial Agents against Acinetobacter baumannii in Experimental Murine Peritoneal Sepsis and Pneumonia Models

    PubMed Central

    Parra Millán, R.; Jiménez Mejías, M. E.; Sánchez Encinales, V.; Ayerbe Algaba, R.; Gutiérrez Valencia, A.; Pachón Ibáñez, M. E.; Díaz, C.; Pérez del Palacio, J.; López Cortés, L. F.; Smani, Y.

    2016-01-01

    Immune response stimulation to prevent infection progression may be an adjuvant to antimicrobial treatment. Lysophosphatidylcholine (LPC) is an immunomodulator involved in immune cell recruitment and activation. In this study, we aimed to evaluate the efficacy of LPC in combination with colistin, tigecycline, or imipenem in experimental murine models of peritoneal sepsis and pneumonia. We used Acinetobacter baumannii strain Ab9, which is susceptible to colistin, tigecycline, and imipenem, and multidrug-resistant strain Ab186, which is susceptible to colistin and resistant to tigecycline and imipenem. Pharmacokinetic and pharmacodynamic parameters for colistin, tigecycline, and imipenem and the 100% minimal lethal dose (MLD100) were determined for both strains. The therapeutic efficacies of LPC, colistin (60 mg/kg of body weight/day), tigecycline (10 mg/kg/day), and imipenem (180 mg/kg/day), alone or in combination, were assessed against Ab9 and Ab186 at the MLD100 in murine peritoneal sepsis and pneumonia models. The levels of pro- and anti-inflammatory cytokines, i.e., tumor necrosis factor alpha (TNF-α) and interleukin-10 (IL-10), were determined by enzyme-linked immunosorbent assay (ELISA) for the same experimental models after inoculating mice with the MLD of both strains. LPC in combination with colistin, tigecycline, or imipenem markedly enhanced the bacterial clearance of Ab9 and Ab186 from the spleen and lungs and reduced bacteremia and mouse mortality rates (P < 0.05) compared with those for colistin, tigecycline, and imipenem monotherapies. Moreover, at 4 h post-bacterial infection, Ab9 induced higher TNF-α and lower IL-10 levels than those with Ab186 (4 μg/ml versus 3 μg/ml [P < 0.05] and 2 μg/ml versus 3.4 μg/ml [P < 0.05], respectively). LPC treatment combined with colistin, tigecycline, or imipenem modestly reduced the severity of infection by A. baumannii strains with different resistance phenotypes compared to LPC monotherapy in both

  13. Activity of selected beta-lactams, ciprofloxacin, and amikacin against different Acinetobacter baumannii biotypes from Chilean hospitals.

    PubMed

    Bello, H; Gonzalez, G; Dominguez, M; Zemelman, R; Garcia, A; Mella, S

    1997-08-01

    The activity of some third generation cephalosporins, aztreonam, imipenem, ciprofloxacin, and amikacin against isolates of Acinetobacter baumannii of various biotypes has been studied. The isolates, independently of the biotype, exhibited a broad multiresistance against cephalosporins. Ceftazidime was the most active and cefoperazone the least active compound. Aztreonam also showed low activity and no imipenem-resistant strains were found. Ciprofloxacin and amikacin were somewhat more active than cephalosporins, but resistant isolates were also frequent. Isolates of Biotypes 9 and 8 exhibited broader multiresistance than those of Biotype 6 and "other."

  14. Antianaerobic activity of sulopenem compared to six other agents.

    PubMed

    Ednie, Lois M; Appelbaum, Peter C

    2009-05-01

    Agar dilution MIC methodology was used to compare the activity of sulopenem with those of amoxicillin/clavulanate, ampicillin/sulbactam, piperacillin-tazobactam, imipenem, clindamycin, and metronidazole against 431 anaerobes. Overall, MIC(50)/(90) values were as follows: sulopenem, 0.25/1.0 microg/ml; amoxicillin/clavulanate, 0.5/2.0 microg/ml; ampicillin/sulbactam, 0.5/4.0 microg/ml; piperacillin/tazobactam, 0.25/8.0 microg/ml; imipenem, 0.06/1.0 microg/ml; clindamycin, 0.25/16.0 microg/ml; and metronidazole, 1.0/4.0 microg/ml.

  15. Molecular characteristics of Multidrug Resistant Acinetobacter baumannii Isolates from US soldiers from Iraq at the National Naval Medical Center

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Infections with A. baumannii-calcoaceticus complex (ABC) have complicated the care of combat casualties, and the spread and global dissemination of imipenem resistant (IR) clones of ABC have been reported in recent years. However, the epidemiological features of the IR-ABCs in military t...

  16. Susceptibilities of Yersinia pestis strains to 12 antimicrobial agents.

    PubMed

    Wong, J D; Barash, J R; Sandfort, R F; Janda, J M

    2000-07-01

    Ninety-two strains of Yersinia pestis recovered over a 21-year period were evaluated for susceptibility to traditional and newer antimicrobial agents. In vitro resistance was noted only against rifampin and imipenem (approximately 20% of strains). The most active compounds (MIC at which 90% of the isolates tested are inhibited) against Y. pestis were cefixime, ceftriaxone, trimethoprim-sulfamethoxazole, and trovafloxacin.

  17. Deep Sequencing of Random Mutant Libraries Reveals the Active Site of the Narrow Specificity CphA Metallo-β-Lactamase is Fragile to Mutations

    PubMed Central

    Sun, Zhizeng; Mehta, Shrenik C.; Adamski, Carolyn J.; Gibbs, Richard A.; Palzkill, Timothy

    2016-01-01

    CphA is a Zn2+-dependent metallo-β-lactamase that efficiently hydrolyzes only carbapenem antibiotics. To understand the sequence requirements for CphA function, single codon random mutant libraries were constructed for residues in and near the active site and mutants were selected for E. coli growth on increasing concentrations of imipenem, a carbapenem antibiotic. At high concentrations of imipenem that select for phenotypically wild-type mutants, the active-site residues exhibit stringent sequence requirements in that nearly all residues in positions that contact zinc, the substrate, or the catalytic water do not tolerate amino acid substitutions. In addition, at high imipenem concentrations a number of residues that do not directly contact zinc or substrate are also essential and do not tolerate substitutions. Biochemical analysis confirmed that amino acid substitutions at essential positions decreased the stability or catalytic activity of the CphA enzyme. Therefore, the CphA active - site is fragile to substitutions, suggesting active-site residues are optimized for imipenem hydrolysis. These results also suggest that resistance to inhibitors targeted to the CphA active site would be slow to develop because of the strong sequence constraints on function. PMID:27616327

  18. In-silico modeling of a novel OXA-51 from β-lactam-resistant Acinetobacter baumannii and its interaction with various antibiotics.

    PubMed

    Tiwari, Vishvanath; Nagpal, Isha; Subbarao, Naidu; Moganty, Rajeswari R

    2012-07-01

    Acinetobacter baumannii, one of the major Gram negative bacteria, causes nosocomial infections such as pneumonia, urinary tract infection, meningitis, etc. β-lactam-based antibiotics like penicillin are used conventionally to treat infections of A. baumannii; however, they are becoming progressively less effective as the bacterium produces diverse types of β-lactamases to inactivate the antibiotics. We have recently identified a novel β-lactamase, OXA-51 from clinical strains of A. baumannii from our hospital. In the present study, we generated the structure of OXA-51 using MODELLER9v7 and studied the interaction of OXA-51 with a number of β-lactams (penicillin, oxacillin, ceftazidime, aztreonam and imipenem) using two independent programs: GLIDE and GOLD. Based on the results of different binding parameters and number of hydrogen bonds, interaction of OXA-51 was found to be maximum with ceftazidime and lowest with imipenem. Further, molecular dynamics simulation results also support this fact. The lowest binding affinity of imipenem to OXA-51 indicates clearly that it is not efficiently cleaved by OXA-51, thus explaining its high potency against resistant A. baumannii. This finding is supported by experimental results from minimum inhibitory concentration analysis and transmission electron microscopy. It can be concluded that carbapenems (imipenem) are presently effective β-lactam antibiotics against resistant strains of A. baumannii harbouring OXA-51. The results presented here could be useful in designing more effective derivatives of carbapenem.

  19. Utilizing the Carba NP test as an indicator of expression level of carbapenemase genes in Enterobacteriaceae.

    PubMed

    Segawa, Takaya; Matsui, Mari; Suzuki, Masato; Tsutsui, Atsuko; Kuroda, Makoto; Shibayama, Keigo; Suzuki, Satowa

    2017-02-01

    The Carba NP test was developed to detect carbapenemase-producing Enterobacteriaceae, and uses imipenem as the reaction substrate. In Japan, IMP-6 metallo-β-lactamase (MBL) producers, which are usually resistant to meropenem but susceptible to imipenem, and IMP-1 MBL producers, which are usually resistant to both carbapenems are prevalent. We performed the Carba NP test with IMP-6 and IMP-1 MBL producers, and both types were detected by the Carba NP test with high sensitivity. All IMP-1 MBL producers were detected by the Carba NP test, but the minimum inhibitory concentrations (MICs) of imipenem varied from 0.25 to >32μg/mL, and the time to positivity varied from 0 to 30min. Time to positivity was significantly correlated with expression levels of blaIMP-1, but not with MICs of imipenem. These results suggested that the Carba NP test can be used as a screening assay for carbapenemase gene expression levels among producers of the same type of carbapenemase. Using this approach, it is possible to determine whether the carbapenem resistance of each carbapenemase-producing Enterobacteriaceae isolate is primarily due to carbapenemase production, or to another mechanism such as outer membrane impermeability.

  20. Detection of KPC-2 in a Clinical Isolate of Proteus mirabilis and First Reported Description of Carbapenemase Resistance Caused by a KPC Beta-Lactamase in P. mirabilis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An isolate of Proteus mirabilis recovered from bacterial cultures was shown to be resistant to imipenem, meropenem, and ertapenem by disk diffusion susceptibility testing. Amplification of whole cell and/or plasmid DNA recovered from the isolate using primers specific for the blaKPC carbapenemase g...

  1. Case report of Streptomyces endocarditis of a prosthetic aortic valve.

    PubMed Central

    Mossad, S B; Tomford, J W; Stewart, R; Ratliff, N B; Hall, G S

    1995-01-01

    We describe the first case of prosthetic valve endocarditis due to a Streptomyces sp. The patient presented with fever, cutaneous embolic lesions, and bacteremia 3 months after aortic valve replacement. Treatment required valve replacement and a long course of parenteral imipenem. PMID:8586732

  2. Persistent Bordetella bronchiseptica pneumonia in an immunocompetent infant and genetic comparison of clinical isolates with kennel cough vaccine strains.

    PubMed

    Rath, Barbara A; Register, Karen B; Wall, Jeffrey; Sokol, Dawn M; Van Dyke, Russell B

    2008-03-15

    An infant who experienced recurrent episodes of respiratory failure received a diagnosis of pertussis on the basis of immunofluorescence testing, but culture revealed macrolide-resistant Bordetella bronchiseptica. Genetic analysis demonstrated that the child was not infected with a kennel cough vaccine strain, although the family's dog had recently been vaccinated. The infection cleared with imipenem therapy.

  3. [Shall we report the carbapenem resistance in Pseudomonas aeruginosa and Acinetobacter baumannii strains detected by BD Phoenix system?].

    PubMed

    Oğünç, Dilara; Ongüt, Gözde; Ozen, Nevgün Sepin; Baysan, Betil Ozhak; Günseren, Filiz; Dağlar, Duygu; Demirbakan, Hadiye; Gültekin, Meral

    2010-04-01

    Imipenem and meropenem are broad spectrum antimicrobial agents that are especially useful in the treatment of nosocomially acquired Pseudomonas aeruginosa and Acinetobacter spp. infections. Previous reports have noted that susceptibility tests could show false resistance to imipenem. For this reason, Centers for Disease Control and Prevention has recommended that all carbapenem resistant or intermediate resistant isolates should be tested with an additional method to verify the results. This study was aimed to evaluate the imipenem and meropenem susceptibilities by disk diffusion, E-test and broth microdilution in P. aeruginosa and Acinetobacter baumannii strains found to be resistant or intermediate to imipenem-meropenem by BD Phoenix automated susceptibility testing system. Between January 2006-January 2007, 85 non-duplicate isolates of A. baumannii and 51 non-duplicate isolates of P. aeruginosa which were determined as resistant or intermediate resistant to imipenem and/or meropenem by BD Phoenix automated identification and susceptibility system (Becton Dickinson, Sparks, MD, USA) were collected in Akdeniz University Hospital Central Laboratory. All strains were tested by E-test (AB Biodisk, Sweden), disk diffusion and reference broth microdilution (BMD) method following CLSI recommendations. All 51 isolates of P. aeruginosa determined as imipenem and/or meropenem resistant or intermediate resistant by BD Phoenix, were found to be imipenem and/or meropenem resistant or intermediate resistant by the reference BMD method. Minor error rates were same for all testing systems (1.9%) except for the meropenem results of BD Phoenix system (5.9%). No major errors were produced by any system. For A. baumannii, only one very major error was detected for meropenem by BD Phoenix system. Number of minor errors determined for meropenem by all testing systems compared to the reference test, ranged from 2 (2.4%) to 3 (3.5%). It was concluded that carbapenem susceptibility test

  4. [Comparative evaluation of in vitro activities of carbapenems against gram-negative pathogens: Turkish data of COMPACT study].

    PubMed

    Korten, Volkan; Söyletir, Güner; Yalçın, Ata Nevzat; Oğünç, Dilara; Dokuzoğuz, Başak; Esener, Harika; Ulusoy, Sercan; Tünger, Alper; Aygen, Bilgehan; Sümerkan, Bülent; Arman, Dilek; Dizbay, Murat; Akova, Murat; Hasçelik, Gülşen; Eraksoy, Haluk; Başaran, Seniha; Köksal, Iftihar; Bayramoğlu, Gülçin; Akalın, Halis; Sınırtaş, Melda

    2011-04-01

    The aim of this study was to determine the in vitro activities of doripenem, imipenem, and meropenem against clinical gram-negative isolates. A total of 596 clinical isolates were obtained from intensive care unit (ICU) and non-ICU patients in 10 centers over Turkey between September-December 2008. The origin of the isolates was patients with nosocomial pneumonia (42.4%), bloodstream infections (%40.4), and complicated intraabdominal infections (17.1%). Of the isolates, 51.8% were obtained from ICU patients. The study isolates consisted of Pseudomonas spp. in 49.8%, Enterobacteriaceae in 40.3%, and other gram-negative agents in 9.9%. The minimum inhibitory concentrations (MIC) for doripenem, imipenem and meropenem were determined for all isolates in each center using Etest® strips (AB Biodisk, Solna, Sweden). Of the isolates, 188 (31.5%) were resistant to at least one of the carbapenems. MIC50 of doripenem against Pseudomonas spp. Was 1 mg/L which was similar to that of meropenem and two-fold lower than imipenem. Susceptibility to carbapenems in P.aeruginosa was 64% for doripenem at an MIC level of 2 mg/L, 53.9% and 63% for imipenem and meropenem at an MIC level of 4 mg/L, respectively. Doripenem and meropenem showed similar activity with the MIC90 of 0.12 mg/L whereas imipenem was four-fold less active at 0.5 mg/L. Against other gramnegative pathogens, mostly Acinetobacter spp., MIC50 was 8 mg/L for doripenem and 32 mg/L for other two carbapenems. P.aeruginosa isolates were inhibited 84.2% with doripenem and 72.1% with meropenem at the MIC level of 8 mg/L. Doripenem generally showed similar or slightly better activity than meropenem and better activity than imipenem against pathogens collected in this study. Against Pseudomonas spp., doripenem was the most active of the three carbapenems. Doripenem and meropenem were equally active against Enterobacteriaceae and at least four-fold more active than imipenem. It was concluded that doripenem seemed to be a promising

  5. Comparative effects of carbapenems on bacterial load and host immune response in a Klebsiella pneumoniae murine pneumonia model.

    PubMed

    Hilliard, Jamese J; Melton, John L; Hall, LeRoy; Abbanat, Darren; Fernandez, Jeffrey; Ward, Christine K; Bunting, Rachel A; Barron, A; Lynch, A Simon; Flamm, Robert K

    2011-02-01

    Doripenem is a carbapenem with potent broad-spectrum activity against Gram-negative pathogens, including antibiotic-resistant Enterobacteriaceae. As the incidence of extended-spectrum β-lactamase (ESBL)-producing Gram-negative bacilli is increasing, it was of interest to examine the in vivo comparative efficacy of doripenem, imipenem, and meropenem against a Klebsiella pneumoniae isolate expressing the TEM-26 ESBL enzyme. In a murine lethal lower respiratory infection model, doripenem reduced the Klebsiella lung burden by 2 log(10) CFU/g lung tissue over the first 48 h of the infection. Treatment of mice with meropenem or imipenem yielded reductions of approximately 1.5 log(10) CFU/g during this time period. Seven days postinfection, Klebsiella titers in the lungs of treated mice decreased an additional 2 log(10) CFU/g relative to those in the lungs of untreated control animals. Lipopolysaccharide (LPS) endotoxin release assays indicated that 6 h postinfection, meropenem- and imipenem-treated animals had 10-fold more endotoxin in lung homogenates and sera than doripenem-treated mice. Following doripenem treatment, the maximum endotoxin release postinfection (6 h) was 53,000 endotoxin units (EU)/ml, which was 2.7- and 6-fold lower than imipenem or meropenem-treated animals, respectively. While the levels of several proinflammatory cytokines increased in both the lungs and sera following intranasal K. pneumoniae inoculation, doripenem treatment, but not meropenem or imipenem treatment, resulted in significantly increased interleukin 6 levels in lung homogenates relative to those in lung homogenates of untreated controls, which may contribute to enhanced neutrophil killing of bacteria in the lung. Histological examination of tissue sections indicated less overall inflammation and tissue damage in doripenem-treated mice, consistent with improved antibacterial efficacy, reduced LPS endotoxin release, and the observed cytokine induction profile.

  6. Molecular epidemiology of Acinetobacter baumannii and Acinetobacter nosocomialis in Germany over a 5-year period (2005-2009).

    PubMed

    Schleicher, X; Higgins, P G; Wisplinghoff, H; Körber-Irrgang, B; Kresken, M; Seifert, H

    2013-08-01

    To investigate the species distribution within the Acinetobacter calcoaceticus-Acinetobacter baumannii complex and the molecular epidemiology of A. baumannii and Acinetobacter nosocomialis, 376 Acinetobacter isolates were collected prospectively from hospitalized patients at 15 medical centres in Germany during three surveillance studies conducted over a 5-year period. Species identification was performed by molecular methods. Imipenem minimum inhibitory concentrations (MIC) were determined by broth microdilution. The prevalence of the most common carbapenemase-encoding genes was investigated by oxacillinase (OXA) -multiplex polymerase chain reaction (PCR). The molecular epidemiology was investigated by repetitive sequence-based PCR (rep-PCR; DiversiLab™). Acinetobacter pittii was the most prevalent Acinetobacter species (n = 193), followed by A. baumannii (n = 140), A. calcoaceticus (n = 10) and A. nosocomialis (n = 8). The majority of A. baumannii was represented by sporadic isolates (n = 70, 50%) that showed unique rep-PCR patterns, 25 isolates (18%) clustered with one or two other isolates, and only 45 isolates (32%) belonged to one of the previously described international clonal lineages. The most prevalent clonal lineage was international clone (IC) 2 (n = 34) and IC 1 (n = 6). According to CLSI, 25 A. baumannii isolates were non-susceptible to imipenem (MIC ≥ 8 mg/L), all of which produced an OXA-58-like or OXA-23-like carbapenemase. The rate of imipenem susceptibility among A. baumannii isolates decreased from 96% in 2005 to 76% in 2009. All other Acinetobacter isolates were susceptible to imipenem. The population structure of carbapenem-susceptible A. baumannii in Germany is highly diverse. Imipenem non-susceptibility was strongly associated with the clonal lineages IC 2 and IC 1. These data underscore the high clonality of carbapenem-resistant A. baumannii isolates.

  7. Increased GVHD-related mortality with broad-spectrum antibiotic use after allogeneic hematopoietic stem cell transplantation in human patients and mice

    PubMed Central

    Shono, Yusuke; Docampo, Melissa D.; Peled, Jonathan U.; Perobelli, Suelen M.; Velardi, Enrico; Tsai, Jennifer J.; Slingerland, Ann E.; Smith, Odette M.; Young, Lauren F.; Gupta, Jyotsna; Lieberman, Sophia R.; Jay, Hillary V.; Ahr, Katya F.; Rodriguez, Kori A. Porosnicu; Xu, Ke; Calarfiore, Marco; Poeck, Hendrik; Caballero, Silvia; Devlin, Sean M.; Rapaport, Franck; Dudakov, Jarrod A.; Hanash, Alan M.; Gyurkocza, Boglarka; Murphy, George F.; Gomes, Camilla; Liu, Chen; Moss, Eli L.; Falconer, Shannon B.; Bhatt, Ami S.; Taur, Ying; Pamer, Eric G.

    2016-01-01

    After allogeneic hematopoietic stem cell transplantation (allo-HSCT), intestinal bacteria modulate risks of infection and graft-versus-host disease (GVHD). Neutropenic fever is common and treated with a choice of clinically equivalent antibiotics that target obligately anaerobic bacteria (anaerobes) to varying degrees. We retrospectively examined 857 allo-HSCT recipients and found that treatment of neutropenic fever with imipenem-cilastatin and piperacillin-tazobactam was associated with increased GVHD-related mortality at 5 years (21.5% in imipenem-cilastatin-treated patients vs. 13.1% in untreated patients, p=0.025, and 19.8% in piperacillin-tazobactam-treated patients vs. 11.9% in untreated patients, p=0.007). However, two other antibiotics also used to treat neutropenic fever, aztreonam and cefepime, were not associated with GVHD-related mortality (p=0.78 and p=0.98, respectively). Analysis of stool microbiota composition showed that piperacillin-tazobactam administration was associated with increased compositional perturbation. Studies in mouse models demonstrated similar effects of these antibiotics, as well as aggravated GVHD mortality with imipenem-cilastatin or piperacillin-tazobactm compared to aztreonam (p<0.01 and p<0.05, respectively). We found pathological evidence for increased GVHD in the colon of imipenem-cilastatin-treated mice (p<0.05), but no differences in short-chain fatty acid concentrations or regulatory T cells numbers. Notably, imipenem-cilastatin treatment of mice with GVHD led to loss of the protective lining of mucus in the colon (p<0.01) and intestinal barrier function was compromised (p<0.05). Sequencing of mouse stool specimens showed expansion of Akkermansia muciniphila (p<0.001), a commensal bacterium with mucus-degrading capabilities, raising the possibility that mucus degradation can contribute to murine GVHD. We demonstrate an underappreciated risk for antibiotics with activity against anaerobes to exacerbate colonic GVHD after

  8. Efficient Detection of Carbapenemase Activity in Enterobacteriaceae by Matrix-Assisted Laser Desorption Ionization−Time of Flight Mass Spectrometry in Less Than 30 Minutes

    PubMed Central

    Lasserre, Camille; De Saint Martin, Luc; Cuzon, Gaelle; Bogaerts, Pierre; Lamar, Estelle; Glupczynski, Youri; Naas, Thierry

    2015-01-01

    The recognition of carbapenemase-producing Enterobacteriaceae (CPE) isolates is a major laboratory challenge, and their inappropriate or delayed detection may have negative impacts on patient management and on the implementation of infection control measures. We describe here a matrix-assisted laser desorption ionization−time of flight (MALDI-TOF)-based method to detect carbapenemase activity in Enterobacteriaceae. After a 20-min incubation of the isolate with 0.5 mg/ml imipenem at 37°C, supernatants were analyzed by MALDI-TOF in order to identify peaks corresponding to imipenem (300 Da) and an imipenem metabolite (254 Da). A total of 223 strains, 77 CPE (OXA-48 variants, KPC, NDM, VIM, IMI, IMP, and NMC-A) and 146 non-CPE (cephalosporinases, extended-spectrum β-lactamases [ESBLs], and porin defects), were tested and used to calculate a ratio of imipenem hydrolysis: mass spectrometry [MS] ratio = metabolite/(imipenem + metabolite). An MS ratio cutoff was statistically determined to classify strains as carbapenemase producers (MS ratio of ≥0.82). We validated this method first by testing 30 of our 223 isolates (15 CPE and 15 non-CPE) 10 times to calculate an intraclass correlation coefficient (ICC of 0.98), showing the excellent repeatability of the method. Second, 43 strains (25 CPE and 18 non-CPE) different from the 223 strains used to calculate the ratio cutoff were used as external controls and blind tested. They yielded sensitivity and specificity of 100%. The total cost per test is <0.10 U.S. dollars (USD). This easy-to-perform assay is time-saving, cost-efficient, and highly reliable and might be used in any routine laboratory, given the availability of mass spectrometry, to detect CPE. PMID:25926485

  9. Antimicrobial activity of doripenem against Gram-negative pathogens: results from INVITA-A-DORI Brazilian study.

    PubMed

    Gales, Ana Cristina; Azevedo, Heber D; Cereda, Rosângela Ferraz; Girardello, Raquel; Xavier, Danilo Elias

    2011-01-01

    In vitro activity of doripenem and comparator antimicrobial agents was evaluated against Gram-negative bacilli recently isolated from Brazilian private hospitals that were enrolled in the INVITA-A-DORI Brazilian Study. A total of 805 unique Gram-negative bacilli were collected from patients hospitalized at 18 medical centers between May/08 and March/09. Each hospital was asked to submit 50 single Gram-negative bacilli isolated from blood, lower respiratory tract or intraabdominal secretions. Bacterial identification was confirmed and antimicrobial susceptibility testing was performed using Clinical Laboratory Standards Institute (CLSI) microdilution method at a central laboratory. CLSI M100-S21 (2011) or US-FDA package insert criteria (tigecycline) was used for interpretation of the antimicrobial susceptibility results. Doripenem was as active as meropenem and more active than imipenem against E. coli and K. pneumoniae isolates. A total of 50.0% of Enterobacter spp. isolates were resistant to ceftazidime but 85.7% of them were inhibited at doripenem MICs < 1 µg/mL. Polymyxin B was the only agent to show potent activity against Acinetobacter spp. (MIC50/90, < 0.5/1 µg/mL) and P. aeruginosa (MIC50/90, 1/2 µg/mL). Although high rates of imipenem (53.1%) and meropenem (44.5%) resistance were detected among P. aeruginosa, doripenem showed MIC50 of 16 µg/mL against imipenem-resistant P. aeruginosa and inhibited a greater number of imipenem-resistant P. aeruginosa (10.5%) at MIC values of < 4 µg/mL than did meropenem (0.0%). In this study, doripenem showed similar in vitro activity to that of meropenem and retained some activity against imipenem-resistant P. aeruginosa isolated from Brazilian medical centers.

  10. Rapid Detection of Carbapenem Resistance in Acinetobacter baumannii Using Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry

    PubMed Central

    Flaudrops, Christophe; Berrazeg, Meryem; Brunel, Jean-Michel; Drissi, Mourad; Mesli, Esma; Touati, Abdelaziz; Rolain, Jean-Marc

    2012-01-01

    Rapid detection of carbapenem-resistant Acinetobacter baumannii strains is critical and will benefit patient care by optimizing antibiotic therapies and preventing outbreaks. Herein we describe the development and successful application of a mass spectrometry profile generated by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) that utilized the imipenem antibiotic for the detection of carbapenem resistance in a large series of A. baumannii clinical isolates from France and Algeria. A total of 106 A. baumannii strains including 63 well-characterized carbapenemase-producing and 43 non-carbapenemase-producing strains, as well as 43 control strains (7 carbapenem-resistant and 36 carbapenem-sensitive strains) were studied. After an incubation of bacteria with imipenem for up to 4 h, the mixture was centrifuged and the supernatant analyzed by MALDI-TOF MS. The presence and absence of peaks representing imipenem and its natural metabolite was analyzed. The result was interpreted as positive for carbapenemase production if the specific peak for imipenem at 300.0 m/z disappeared during the incubation time and if the peak of the natural metabolite at 254.0 m/z increased as measured by the area under the curves leading to a ratio between the peak for imipenem and its metabolite being <0.5. This assay, which was applied to the large series of A. baumannii clinical isolates, showed a sensitivity of 100.0% and a specificity of 100.0%. Our study is the first to demonstrate that this quick and simple assay can be used as a routine tool as a point-of-care method for the identification of A. baumannii carbapenemase-producers in an effort to prevent outbreaks and the spread of uncontrollable superbugs. PMID:22359616

  11. Surveillance and correlation of antibiotic prescription and resistance of Gram-negative bacteria in Singaporean hospitals.

    PubMed

    Hsu, Li-Yang; Tan, Thean-Yen; Tam, Vincent H; Kwa, Andrea; Fisher, Dale Andrew; Koh, Tse-Hsien

    2010-03-01

    A surveillance study was performed in four Singapore public hospitals from 2006 to 2008 to determine the correlation between antibiotic prescription and Gram-negative bacterial antimicrobial resistance. Targeted organisms included ceftriaxone- and ciprofloxacin-resistant Escherichia coli and Klebsiella pneumoniae, as well as imipenem-resistant Pseudomonas aeruginosa and Acinetobacter spp. Antibiotic prescription data were collated in the WHO anatomical therapeutic chemical (ATC)/defined daily dose (DDD) format, while antibiotic resistance was expressed as incidence density adjusted for total inpatient-days every quarter. Individual trends were determined by linear regression, while possible associations between antibiotic prescription and resistance were evaluated via cross-correlation analysis. Results over 3 years indicated significantly rising incidence densities of ceftriaxone- and ciprofloxacin-resistant E. coli and imipenem-resistant Acinetobacter spp. (blood isolates only). Antimicrobial-resistant Klebsiella pneumoniae rates declined. The prescription rates of piperacillin-tazobactam, ertapenem, meropenem, ciprofloxacin, and levofloxacin increased significantly, while imipenem and moxifloxacin prescription decreased. Cross-correlation analysis demonstrated possible associations between prescription of fluoroquinolones and ciprofloxacin-resistant E. coli (R(2) = 0.46), fluoroquinolones and ceftriaxone-resistant E. coli (R(2) = 0.47), and carbapenems and imipenem-resistant Acinetobacter spp. (R(2) = 0.48), all at zero time lag. Changes in meropenem prescription were associated with a similar trend in imipenem-resistant Acinetobacter blood isolates after a 3-month time lag. No correlation was found between cephalosporin use and resistance. In conclusion, our data demonstrated correlation between prescription of and Gram-negative bacterial resistance to several, but not all, key antimicrobial agents in Singapore hospitals. In areas where Gram-negative bacterial

  12. In vitro antibacterial activity of TOC-50, a new parenteral cephalosporin against methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis.

    PubMed

    Nomura, S; Hanaki, H; Unemi, N

    1996-01-01

    The in vitro activity of TOC-50, a new parenteral cephalosporin, was assessed against methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis (MRSE). TOC-50 showed excellent activity, which was stronger than that of methicillin, cloxacillin, the cephalosporins tested, imipenem, gentamycin, minocycline, ofloxacin and ciprofloxacin against MRSA and had a minimum inhibitory concentration (MIC) comparable to that of vancomycin (the MICs of TOC-50 and vancomycin for growth inhibition of 90% of the strains tested were 3.13 and 1.56 micrograms/ml, respectively). Against MRSE, TOC-50 exhibited excellent activity, which was stronger than that of methicillin, ampicillin, the cephalosporins tested and imipenem, and was twice as active as vancomycin. In terms of the bactericidal effect against MRSA, TOC-50 was superior to vancomycin.

  13. Patterns of virulence factor expression and antimicrobial resistance in Achromobacter xylosoxidans and Achromobacter ruhlandii isolates from patients with cystic fibrosis.

    PubMed

    Pereira, R H V; Leão, R S; Carvalho-Assef, A P; Albano, R M; Rodrigues, E R A; Firmida, M C; Folescu, T W; Plotkowski, M C; Bernardo, V G; Marques, E A

    2017-02-01

    Achromobacter spp. are opportunistic pathogens increasingly recovered from adult patients with cystic fibrosis (CF). We report the characterization of 122 Achromobacter spp. isolates recovered from 39 CF patients by multilocus sequence typing, virulence traits, and susceptibility to antimicrobials. Two species, A. xylosoxidans (77%) and A. ruhlandii (23%) were identified. All isolates showed a similar biofilm formation ability, and a positive swimming phenotype. By contrast, 4·3% and 44·4% of A. xylosoxidans and A. ruhlandii, respectively, exhibited a negative swarming phenotype, making the swimming and swarming abilities of A. xylosoxidans significantly higher than those of A. ruhlandii. A. xylosoxidans isolates from an outbreak clone also exhibited significantly higher motility. Both species were generally susceptible to ceftazidime, ciprofloxacin, imipenem and trimethoprim/sulphamethoxazole and there was no significant difference in susceptibility between isolates from chronic or sporadic infection. However, A. xylosoxidans isolates from chronic and sporadic cases were significantly more resistant to imipenem and ceftazidime than isolates of the outbreak clone.

  14. [Spreading and mechanisms of antimicrobial resistance of microorganisms, producing beta-lactamases. Phenotypical screening for MBL producers (carbapenemases B1) among strains of Pseudomonas genus, isolated in cases of nosocomial infections].

    PubMed

    Ivanov, D V; Egorov, A M

    2007-01-01

    Intrahospital strains (215) of the bacterial genus Pseudomonas isolated from patients of 30 Medical centers of 15 Russian regions have been investigated for antibiotic resistance. The bacterial cultures resistant to imipenem and/or meropenem were considered as metallo-beta-lactamase (MBL) producers. Production of subclass B1 MBL (carbapenemases) was evaluated by means of the double-disk approximation test using MBL inhibitor, EDTA. There were 55 P. aeroginosa strains (25.6%) resistant to imipenem and meropenem simultaneously; 19 isolates (8.8%) of P. aeroginosa were characterized by synergism between carbapenem and EDTA. The subclass B1 MBL producers are widely distributed in the intrahospital strain obtained from Moscow, Yaroslavl, Ekaterinburg, Omsk, and Tomsk hospitals.

  15. Metallo-β-Lactamase-Producing Pseudomonas spp. in Korea: High Prevalence of Isolates with VIM-2 Type and Emergence of Isolates with IMP-1 Type

    PubMed Central

    Lee, Kyungwon; Park, Ae Ja; Kim, Moon Yeun; Lee, Hee Joo; Cho, Ji-Hyun; Kang, Jung Oak; Yong, Dongeun

    2009-01-01

    Purpose Two Korean nationwide studies showed that metallo-β-lactamases (MBLs)-producing-Pseudomonas spp. are not rare. The aim of this study was to assess the trends of MBL-producing isolates among imipenem-resistant isolates of Pseudomonas spp. Materials and Methods Imipenem-resistant clinical isolates were collected from 23 hospitals and one commercial laboratory participating in the KONSAR program in 2005. Polymerase chain reaction (PCR) was used to detect MBL genes. Results Alleles of MBL genes were detected in 10.8% of 415 Pseudomonas aeruginosa and 66.7% of 12 P. putida isolates from 18 of 24 hospitals/laboratory. Among the 14 IMP-1-like and 39 VIM-2-like MBLs, emergence of IMP-6 was detected for the first time. Conclusion Prevalence of MBL-producing P. aeruginosa has not significantly increased, but IMP-6 emerged in P. aeruginosa. PMID:19568593

  16. Antianaerobic Activity of Sulopenem Compared to Six Other Agents ▿

    PubMed Central

    Ednie, Lois M.; Appelbaum, Peter C.

    2009-01-01

    Agar dilution MIC methodology was used to compare the activity of sulopenem with those of amoxicillin/clavulanate, ampicillin/sulbactam, piperacillin-tazobactam, imipenem, clindamycin, and metronidazole against 431 anaerobes. Overall, MIC50/90 values were as follows: sulopenem, 0.25/1.0 μg/ml; amoxicillin/clavulanate, 0.5/2.0 μg/ml; ampicillin/sulbactam, 0.5/4.0 μg/ml; piperacillin/tazobactam, 0.25/8.0 μg/ml; imipenem, 0.06/1.0 μg/ml; clindamycin, 0.25/16.0 μg/ml; and metronidazole, 1.0/4.0 μg/ml. PMID:19223615

  17. Carbapenem-based prodrugs. Design, synthesis, and biological evaluation of carbapenems.

    PubMed

    Hakimelahi, Gholam Hossein; Moosavi-Movahedi, Ali Akbar; Saboury, Ali Akbar; Osetrov, Valeriy; Khodarahmi, Ghadam Ali; Shia, Kak-Shan

    2005-04-01

    Syntheses of racemic trans-3-hydroxycarbonyl-6-(phenylacetamido)carbapenem (13), trans-3-phosphono-6-(phenylacetamido)carbapenem (17), and beta-lactam based prodrugs 19 and 22 were accomplished. Carbapenem 13 was found to possess antibacterial activity, comparable with imipenem (+)-3, against Staphylococcus aureus FDA 209P, S. aureus 95, Escherichia coli ATCC 39188, Klebsiella pneumoniae NCTC 418, Pseudomonas aeruginosa 1101-75, P. aeruginosa 18S-H, and Xanthomonas maltophilia GN 12873. Like imipenem ((+)-3), carbapenem 13 was not stable to X. maltophilia oxyiminocephalosporinase type II. Its phosphonate analog 17, however, was neither a significant antibacterial agent nor a good beta-lactamase inhibitor. Chemical combinations of trans carbapenem 13 with cis carbapenem 6 (compound 19) as well as clavulanic acid (20) with cis carbapenem 6 (compound 22) via a tetrachloroethane linker exhibited remarkable activity against beta-lactamase producing microorganisms in vitro.

  18. Successful Management of Multidrug-Resistant Pseudomonas aeruginosa Pneumonia after Kidney Transplantation in a Dog

    PubMed Central

    PARK, Kyung-Mee; NAM, Hyun-Suk; WOO, Heung-Myong

    2013-01-01

    ABSTRACT An 8-year-old male mongrel dog that had undergone renal transplantation was presented 25 days later with an acute cough, anorexia and exercise intolerance. During the investigation, neutrophilic leukocytosis was noted, and thoracic radiographs revealed caudal lung lobe infiltration. While being treated with two broad-spectrum antibiotics, clinical signs worsened. Pneumonia due to infection with multidrug-resistant (MDR) Pseudomonas (P.) aeruginosa, sensitive only to imipenem and amikacin, was confirmed by bacteria isolation. After treatment with imipenem-cilastatin without reducing the immunosuppressant dose, clinical signs completely resolved. During the 2-year follow-up period, no recurrence was observed. To the best of authors’ knowledge, this is the first report of pneumonia caused by MDR P. aeruginosa in a renal recipient dog and successful management of this disease. PMID:23842146

  19. Carbapenem stewardship: does ertapenem affect Pseudomonas susceptibility to other carbapenems? A review of the evidence.

    PubMed

    Nicolau, David P; Carmeli, Yehuda; Crank, Christopher W; Goff, Debra A; Graber, Christopher J; Lima, Ana Lucia L; Goldstein, Ellie J C

    2012-01-01

    The group 2 carbapenems (imipenem, meropenem and, more recently, doripenem) have been a mainstay of treatment for patients with serious hospital infections caused by Pseudomonas aeruginosa, Enterobacteriaceae and other difficult-to-treat Gram-negative pathogens as well as mixed aerobic/anaerobic infections. When ertapenem, a group 1 carbapenem, was introduced, questions were raised about the potential for ertapenem to select for imipenem- and meropenem-resistant Pseudomonas. Results from ten clinical studies evaluating the effect of ertapenem use on the susceptibility of Pseudomonas to carbapenems have uniformly shown that ertapenem use does not result in decreased Pseudomonas susceptibility to these antipseudomonal carbapenems. Here we review these studies evaluating the evidence of how ertapenem use affects P. aeruginosa as well as provide considerations for ertapenem use in the context of institutional stewardship initiatives.

  20. Comparative evaluation of a new commercial media, the CHROMAgar™ mSuperCARBA™, for the detection of carbapenemase-producing Enterobacteriaceae.

    PubMed

    Amar, Ma'ayan; Shalom, Ohad; Adler, Amos

    2017-02-11

    A new chromogenic-based medium (mSuperCARBA™) was tested for screening carbapenemase-producing Enterobacteriaceae (CPE). mSuperCARBA™ was more sensitive (83%) in detecting CPE isolates (n=69, including KPC, NDM, OXA-48, VIM, and IMI) compared with CHROMAgar™-KPC (65%) and MacConkey agar with Imipenem (69%) with comparable specificity for non carbapenemase-producing, carbapenem-resistant Enterobacteriaceae (n=29).

  1. [Multiple antibiotic resistance of associative microflora during urogenital pathology].

    PubMed

    Akaeva, F S; Omarova, S M; Adieva, A A; Medzhidov, M M

    2008-01-01

    Susceptibility of associative microflora isolated from patients with inflammatory diseases of urogenital tract was investigated. Etiologic structure of the diseases and cross-resistance to antibiotics of Escherichia coli, Staphylococcusaureus, and Klebsiella pneumoniae strains isolated from women with endocervicitis and men with urethritiswas assessed. Ciprofloxacin and gentamycin had the highest activity, whereas beta-lactam antibiotics were mildly active. Isolated strainswere resistant to macrolides, penicillines and imipenem. Main types of multidrug resistance to antibiotics were presented in strains circulated in Dagestan.

  2. Infectious Complications of Open Type III Tibial Fractures among Combat Casualties

    DTIC Science & Technology

    2007-08-15

    Escherichia coli 2 1 Stenotrophomonas maltophilia 1 0 Unknown 1 0 Gram-positive Coagulase-negative staphylococci 3 7 Enterococcus species 3 0 MSSA 2b 5...aeruginosa (6) Amputation (9)c 8 25 (M, IIIb) CoNS ( Escherichia coli and En- terobacter species recovered from broth) (30) Imipenem-cilastatin (2...nonunion wound; this organisim was a methicillin- resistant Staphylococcus aureus strain that was inadvertently not treated. Five of 35 patients

  3. The characteristics of metallo-β-lactamase-producing gram-negative bacilli isolated from sputum and urine: a single center experience in Korea.

    PubMed

    Chin, Bum Sik; Han, Sang Hoon; Choi, Suk Hoon; Lee, Han Sung; Jeong, Su Jin; Choi, Hee Kyung; Choi, Jun Yong; Song, Young Goo; Kim, Chang Ki; Yong, Dongeun; Lee, Kyungwon; Kim, June Myung

    2011-03-01

    Metallo-β-lactamase (MBL) production usually results in high-level resistance to most β-lactams, and a rapid spread of MBL producing major gram-negative pathogens is a matter of particular concern worldwide. However, clinical data are scarce and most studies compared MBL producer (MP) with MBL non-producer (MNP) strains which included carbapenem susceptible isolates. Therefore, we collected clinical data of patients in whom imipenem-nonsusceptible Pseudomonas aeruginosa (PA) and Acinetobacter baumannii (AB) were isolated from sputum or urine, and investigated MBL production and the risk factors related with MBL acquisition. The antimicrobial susceptibility patterns were also compared between MPs and imipenem-nonsusceptible MNPs (INMNP). Among the 176 imipenem-nonsusceptible isolates, 12 MPs (6.8%) were identified. There was no identifiable risk factor that contributed to the acquisition of MPs when compared to INMNPs, and case-fatalities were not different between the two groups. The percentage of susceptible isolates was higher among MPs for piperacilin/tazobactam and fluoroquinolones while that of ceftazidime was higher in INMNPs (p < 0.05). As regards to aztreonam, which has been known to be a uniquely stable β-lactam against MBLs, susceptibility was preserved in only two isolates (16.7%) among MPs, and was not higher than that of INMNPs (23.2%). In conclusion, the contribution of MBLs to imipenem non-susceptibility in PA/ABs isolated from sputum and urine was relatively limited, and there was no significant risk factor associated with acquisition of MPs compared with INMNPs. However, limited susceptibility to aztreonam implies that MPs may hold additional resistance mechanisms, such as extended spectrum β-lactamases, AmpC β-lactamases, or other non-enzymatic mechanisms.

  4. Necrotizing gastritis due to Bacillus cereus in an immunocompromised patient.

    PubMed

    Le Scanff, J; Mohammedi, I; Thiebaut, A; Martin, O; Argaud, L; Robert, D

    2006-04-01

    Bacillus cereus is increasingly being acknowledged as a serious bacterial pathogen in immunocompromised patients. We present a case of acute necrotizing gastritis caused by B. cereus in a 37-year-old woman with acute myeloblastic leukemia, who recovered following total parenteral nutrition and treatment with imipenem and vancomycin. B. cereus was isolated from gastric mucosa and blood cultures. Up to now, no case of acute necrotizing gastritis due to this organism has been reported.

  5. In vitro comparison of Pseudomonas aeruginosa isolates with various susceptibilities to aminoglycosides and ten beta-lactam antibiotics.

    PubMed Central

    Wu, D H; Baltch, A L; Smith, R P

    1984-01-01

    Susceptibilities of 98 clinical isolates of Pseudomonas aeruginosa, including 33 strains with known mechanisms of amikacin resistance, were tested by the agar dilution method against 10 beta-lactam drugs. Ceftazidime, imipenem, and cefsulodin had the greatest activity, regardless of the aminoglycoside susceptibilities. The strains which were highly resistant to amikacin appeared to be less susceptible to some beta-lactam drugs, especially if their resistance was related to amikacin-inactivating enzymes; statistical significance, however, was observed for aztreonam only. PMID:6428308

  6. Spectrophotometry-based detection of carbapenemase producers among Enterobacteriaceae.

    PubMed

    Bernabeu, Sandrine; Poirel, Laurent; Nordmann, Patrice

    2012-09-01

    Carbapenem-hydrolyzing ß-lactamases are the most powerful ß-lactamases being able to hydrolyse almost all ß-lactams. They are mostly of the KPC, VIM, IMP, NDM, and OXA-48 type. A spectrophotometry technique based on analysis of the imipenem hydrolysis has been developed that differentiated carbapenemase- from noncarbapenemase producers. This inexpensive technique adapted to screening of carbapenemase producers may be implemented in any reference laboratory worldwide.

  7. Epidemiology of carbapenem resistant Enterobacteriaceae (CRE) during 2000-2012 in Asia

    PubMed Central

    Xu, Yanling; Gu, Bing; Huang, Mao; Liu, Haiyan; Xu, Ting; Xia, Wenying

    2015-01-01

    Background Over the past decade, the worldwide emergence of carbapenem resistance in Enterobacteriaceae has become a severe public health issue. This meta-analysis aims to describe the epidemiology of carbapenem resistant Enterobacteriaceae (CRE) during the years of 2000-2012 in Asian area. Methods PubMed and Embase databases were searched to identify the qualified papers. Random or fixed-effect model was used to deal with the data. Results Over all the 49 Asian countries (or regions), only 37.5% [19] of them contributed epidemiology data of CRE, and the rest ones provided either only case reports or no information at all. In Asia, the prevalence of CRE was still low during the study period with average resistance rates of 0.6% (95% CI, 0.6-0.8%, imipenem) and 0.9% (95% CI, 0.7-1.2%, meropenem). Resistance rates to imipenem and meropenem in Enterobacteriaceae exhibited stably escalating trend. Similar trend can also be observed among each Enterobacteriaceae genus, such as E. coli, Klebsiella spp. and Enterobacer spp. Klebsiella spp. accounted for the largest proportion among the isolates resistant to imipenem, and then followed by E. coli and Serratia. The rank order of resistance rates to imipenem among Enterobacteriaceae genus during the period of 2000-2012 was as follows: Serratia spp. (1.8%) > Proteus spp. (1.6%) > Klebsiella spp. (0.8%) = Citrobacter spp. (0.8%) > Enterobacer spp. (0.7%) > E. coli (0.2%). Conclusions Given the fact that the prevalence of CRE was increasing during the past decade, it is urgent for us to establish regional surveillance worldwide, carry out more effective antibiotic stewardship and infection control measures to prevent further spread of carbapenem resistance in Enterobacteriaceae. PMID:25922715

  8. Outbreak of OXY-2-Producing Klebsiella oxytoca in a Renal Transplant Unit▿

    PubMed Central

    Zárate, Mariela Soledad; Gales, Ana C.; Picão, Renata C.; Pujol, Gervasio Soler; Lanza, Alejandra; Smayevsky, Jorgelina

    2008-01-01

    We describe a Klebsiella oxytoca infection outbreak in a renal transplant unit that involved seven patients. All strains belonged to a single pulsed-field gel electrophoresis pattern and were resistant to amoxicillin-clavulanate, cefuroxime, piperacillin-tazobactam, and aztreonam but susceptible to ceftriaxone, ceftazidime, cefepime, and imipenem. Chromosomal β-lactamase hyperproduction was caused by a point mutation in the blaOXY-2 gene promoter region. PMID:18417660

  9. Rapid discrimination of blaIMP-1, blaIMP-6, and blaIMP-34 using a multiplex PCR.

    PubMed

    Kayama, Shizuo; Ohge, Hiroki; Sugai, Motoyuki

    2017-04-01

    Stealth-type carbapenem-resistant Enterobacteriaceae that are resistant to almost all β-lactams except imipenem is emerging in Japan. This resistance is mediated by specific variants of the metallo-β-lactamases (blaIMP-6 or blaIMP-34) that differs by one amino acid from the common variant blaIMP-1. We developed an amplification refractory mutation system (ARMS) PCR assay enabling rapid, sequence independent, identification of these variants.

  10. Genetic and biochemical characterization of a chromosome-encoded carbapenem-hydrolyzing ambler class D beta-lactamase from Shewanella algae.

    PubMed

    Héritier, Claire; Poirel, Laurent; Nordmann, Patrice

    2004-05-01

    A chromosome-encoded beta-lactamase gene from Shewanella algae clinical isolate KB-1 was cloned and expressed in Escherichia coli. It encoded the Ambler class D enzyme OXA-55, sharing less than 55% identity with any other oxacillinases. Although conferring a narrow-spectrum beta-lactam resistance phenotype, OXA-55 had carbapenem-hydrolyzing activity that mirrored the reduced susceptibility to imipenem observed in S. algae KB-1. Very similar oxacillinases were found in other S. algae isolates.

  11. [A case of melioidosis in Argentina].

    PubMed

    Almuzara, Marisa; Barberis, Claudia; Bravo, Martín; Pisarevsky, Andrea; Petrucci, Enrique; Famiglietti, Angela; Lasala, María; Vay, Carlos

    2011-01-01

    We describe a case of 17-year- old man native of Dominican Republic, with Hodgkin's lymphoma, who presented soft espontaneous draining nodules. In the clinical samples grew Burkholderia pseudomallei; the etiological agent of melioidosis. He received antimicrobial treatment with imipenem and amoxicillin/clavulanic with very good clinical evolution of the infectious process. Melioidosis diagnosis could be underestimated due to the low incidence of Burkholderia pseudomallei in our continent. The definitive diagnosis depends of the isolation and identification in the clinical sample.

  12. Evaluation of an automated system for the detection of carbapenem resistant Acinetobacter baumannii and assessment of metallo-β-lactamase production using two different phenotyping methods.

    PubMed

    Aybey, Askin Derya; Aksit, Filiz; Oz, Yasemin; Kiremitci, Abdurrahman; Durmaz, Gul

    2011-07-01

    We tested 200 clinical Acinetobacter baumannii isolates against imipenem and meropenem using the methods of broth microdilution, disk diffusion, agar dilution, MicroScan/WalkAway automated system. Very major errors were mostly obtained between MicroScan/WA system and disk diffusion test. MicroScan/WA system generated unacceptable errors. Combined disk and modified Hodge tests used for detection of metallo-β-lactamase production were practical and useful.

  13. Prevalence of Multidrug-Resistant Bacteria on Fresh Vegetables Collected from Farmers' Markets in Connecticut.

    PubMed

    Karumathil, Deepti Prasad; Yin, Hsin-Bai; Kollanoor-Johny, Anup; Venkitanarayanan, Kumar

    2016-08-01

    This study determined the prevalence of multidrug-resistant (MDR) Acinetobacter baumannii on fresh vegetables collected from farmers' markets in Connecticut. One hundred samples each of fresh carrots, potatoes, and lettuce were sampled and streaked on selective media, namely Leeds Acinetobacter and MDR Acinetobacter agars. All morphologically different colonies from MDR Acinetobacter agar were identified by using Gram staining, biochemical tests, and PCR. In addition, susceptibility of the isolates to 10 antibiotics commonly used in humans, namely imipenem, ceftriaxone, cefepime, minocycline, erythromycin, colistin-sulfate, streptomycin, neomycin, doxycycline, and rifampin was determined by using an antibiotic disk diffusion assay. The results revealed that only two samples of potato and one sample of lettuce yielded A. baumannii. In addition, all carrot samples were found to be negative for the organism. However, several other opportunistic, MDR human pathogens, such as Burkholderia cepacia (1% potatoes, 5% carrots, and none in lettuce), Stenotrophomonas maltophilia (6% potatoes, 2% lettuce, and none in carrots), and Pseudomonas luteola (9% potatoes, 3% carrots, and none in lettuce) were recovered from the vegetables. Antibiotic susceptibility screening of the isolates revealed high resistance rates for the following: ceftriaxone (6 of 6), colistin-sulfate (5 of 6), erythromycin (5 of 6), and streptomycin (4 of 6) in B. cepacia; colistin-sulfate (11 of 11) and imipenem (10 of 11) in P. luteola; colistin-sulfate (8 of 8), ceftriaxone (8 of 8), cefepime (7 of 8), erythromycin (5 of 8), and imipenem (4 of 8) in S. maltophilia; and imipenem (3 of 3), ceftriaxone (3 of 3), erythromycin (3 of 3), and streptomycin (3 of 3) in A. baumannii. The results revealed the presence of MDR bacteria, including human pathogens on fresh produce, thereby highlighting the potential health risk in consumers, especially those with a compromised immune system.

  14. Emergence of Escherichia coli Sequence Type ST131 Carrying both the blaGES-5 and blaCTX-M-15 Genes▿

    PubMed Central

    Kim, Juwon; Hong, Seong Geun; Bae, Il Kwon; Kang, Ji Roung; Jeong, Seok Hoon; Lee, Wookeun; Lee, Kyungwon

    2011-01-01

    Escherichia coli clinical isolate BD07372 of sequence type ST131 recovered from a bed sore specimen exhibited high-level resistance to ceftazidime and cefotaxime but exhibited susceptibility to imipenem and meropenem. The isolate harbored two β-lactamase genes, the blaCTX-M-15 gene carried by an ∼250-kbp plasmid carrying the FIA and FIC replicons and the blaGES-5 gene carried by a class 1 integron in the chromosome. PMID:21444709

  15. Novel Bis-Indole Agents Active Against Multidrug-Resistant Acinetobacter baumannii

    PubMed Central

    Jacobs, Michael R.; Bajaksouzian, Saralee; Good, Caryn E.; Butler, Michelle M.; Williams, John D.; Peet, Norton P.; Bowlin, Terry L.; Endimiani, Andrea; Bonomo, Robert A

    2013-01-01

    The in vitro activity of five novel Microbiotix bis-indole agents (MBXs) against 30 multidrug-resistant (MDR) A. baumannii (including 18 resistant to carbapenems) was evaluated. Overall, MIC90s ranged from 1-8 μg/ml, whereas those for imipenem were > 64 μg/ml. MBX 1196 was the most potent (MIC90 1 μg/ml). MBXs are compounds that are highly effective against MDR A. baumannii. PMID:21146724

  16. Outbreak of OXY-2-Producing Klebsiella oxytoca in a renal transplant unit.

    PubMed

    Zárate, Mariela Soledad; Gales, Ana C; Picão, Renata C; Pujol, Gervasio Soler; Lanza, Alejandra; Smayevsky, Jorgelina

    2008-06-01

    We describe a Klebsiella oxytoca infection outbreak in a renal transplant unit that involved seven patients. All strains belonged to a single pulsed-field gel electrophoresis pattern and were resistant to amoxicillin-clavulanate, cefuroxime, piperacillin-tazobactam, and aztreonam but susceptible to ceftriaxone, ceftazidime, cefepime, and imipenem. Chromosomal beta-lactamase hyperproduction was caused by a point mutation in the bla(OXY-2) gene promoter region.

  17. Emergence of NDM – 1 in the Clinical Isolates of Pseudomonas aeruginosa in India

    PubMed Central

    Khajuria, Atul; Praharaj, Ashok Kumar; Kumar, Mahadevan; Grover, Naveen

    2013-01-01

    Objective: The present study was undertaken to detect the prevalence of the blaNDM-1 metallo beta lactamases (MBLs) in the isolates of Pseudomonas aeruginosa, which were recovered from various clinical samples from hospitalized patients in a tertiary care centre in Pune, India. Methods: A total of 200 isolates of P. aeruginosa which were obtained from various clinical samples were subjected to antibiotic susceptibility testing by the disc-diffusion method and their MICs were determined by the Vitek – 2 Automated Antimicrobial Identification and Susceptibility Testing System against imipenem, meropenem, ticarcillin, amikacin, gentamicin, tobramycin, ciprofloxacin, levofloxacin, moxifloxacin, tigecycline, trimethoprim/sulfamethoxazole, ampicillin/sulbactam, piperacillin/tazobactam, cefoperazone/sulbactam, cefepime, tetracycline, ceftazidime, ceftriaxone and colistin. Their MICs were also determined by the Etest method against imipenem, meropenem, piperacillin, tobramycin, ceftazidime, tigecycline and colistin. The presence of blaNDM-1 was detected by PCR and it was confirmed by sequencing the gene which was present in the isolates which exhibited carbapenem resistance. The experimental transferability of the plasmids which carried blaNDM-1 was determined by using E. coli J53 as the recipient. Result: In the present study, four isolates of P. aeruginosa, which carried the blaNDM-1 gene, were resistant to imipenem and meropenem. These blaNDM-1 carrying isolates remained susceptible to colistin. The plasmid carrying blaNDM-1 was successfully transferred from the four isolates to E. coli J53 recipients. Conclusions: We are reporting the emergence of the P. aeruginosa carrying NDM-1gene, which exhibited resistance to imipenem and meropenem, for the first time from India. PMID:23998058

  18. Detection and Genetic Characterization of Metallo-β-Lactamase IMP-1 and VIM-2 in Pseudomonas aeruginosa Strains From Different Hospitals in Kermanshah, Iran

    PubMed Central

    Abiri, Ramin; Mohammadi, Pantea; Shavani, Navid; Rezaei, Mansour

    2015-01-01

    Background: Pseudomonas aeruginosais a frequent nosocomial pathogen that causes severe diseases in many settings. Carbapenems, including meropenem and imipenem, are effective antibiotics against this organism. However, the use of carbapenems has been hampered by the emergence of strains resistant to carbapenemsvia different mechanisms such as the production of metallo-β-lactamases (MBLs), which hydrolyze all carbapenems. Several kinds of MBLs have been reported, among them VIM and IMP types being the most clinically significant carbapenemases. Objectives: We aimed to determine the distribution of blaVIM-2 and blaIMP-1 transferable genes encoding MBLs in P. aeruginosa isolated from three academic hospitals in Kermanshah. Patients and Methods: From 22nd June to 22nd September 2012, 225 isolates of P. aeruginosa were collected. These isolates were tested for antibiotic susceptibility with the Kirby-Bauer disk-diffusion method, and the MBLs were assessed using the imipenem-EDTA double-disk synergy test. The isolates were investigated for blaVIM-2 and blaIMP-1 genes using polymerase chain reaction. Results: Among the 225 isolates, 33.7% (76/225) and 18.1% (41/225) were resistant to imipenem and meropenem, respectively. Of the 76 imipenem-resistant P. aeruginosa strains, 45 (59.2%) were positive for MBLs, 34 (75%) strains carried the blaIMP-1 gene, and 1 (2.2%) strain carried the blaVIM-2 gene. Conclusions: Our results showed that there was a high frequency of IMP-1 positive P. aeruginosa in the different wards of the hospitals. PMID:26495110

  19. Carbapenems: a potent class of antibiotics.

    PubMed

    Nicolau, David P

    2008-01-01

    The purpose of this review is to assess the relative strengths and weaknesses of individual members of the carbapenem class of antibiotics. Clinical trials and review articles were identified from a Medline search (1979 - July 2006), in addition to, reference citations from identified publications, abstracts from the Interscience Conferences on Antimicrobial Agents and Chemotherapy and the 12th International Congress on Infectious Disease, and package inserts. Articles in English were reviewed, with emphasis on those containing efficacy or safety data. Carbapenems bind to critical penicillin-binding proteins, disrupting the growth and structural integrity of bacterial cell walls. They provide enhanced anaerobic and Gram-negative coverage as compared with other beta-lactams and their stability against extended-spectrum beta-lactamases (ESBLs) makes them an effective treatment option. The most common adverse effects are infusion-site complications and gastrointestinal distress. Ertapenem has limited efficacy against non-fermenting, Gram-negative bacteria, restricting its use to community-acquired infections. Imipenem is slightly more effective against Gram-positive organisms and meropenem slightly more effective against Gram-negative organisms. However, both have broad-spectrum activity, including non-fermenting, Gram-negative bacteria. Among non-fermenting, Gram-negatives, resistance to imipenem in particular is increasing. Doripenem is in late-stage clinical development and combines the broad-spectrum coverage of imipenem and meropenem, and more potent activity against Pseudomonas aeruginosa. Due to the increasing challenges represented by ESBLs and multi-drug resistant organisms, the carbapenems are assuming a greater role in the treatment of serious infections. Imipenem and meropenem are presently available and have been shown to be effective against nosocomial infections. Doripenem is an investigational carbapenem that has completed Phase III clinical trials and

  20. Comparative in vitro activity of carbapenems against major Gram-negative pathogens: results of Asia-Pacific surveillance from the COMPACT II study.

    PubMed

    Kiratisin, Pattarachai; Chongthaleong, Anan; Tan, Thean Yen; Lagamayo, Evelina; Roberts, Sally; Garcia, Jemelyn; Davies, Todd

    2012-04-01

    Resistance rates amongst Gram-negative pathogens are increasing in the Asia-Pacific region. The Comparative Activity of Carbapenem Testing (COMPACT) II study surveyed the carbapenem susceptibility and minimum inhibitory concentrations (MICs) of doripenem, imipenem and meropenem against 1260 major Gram-negative pathogens isolated from hospitalised patients at 20 centres in five Asia-Pacific countries (New Zealand, the Philippines, Singapore, Thailand and Vietnam) during 2010. Pseudomonas aeruginosa (n=625), Enterobacteriaceae (n=500), and other Gram-negative pathogens including Acinetobacter baumannii (n=135) were collected from patients with bloodstream infection (32.2%), nosocomial pneumonia including ventilator-associated pneumonia (58.1%), and complicated intra-abdominal infection (9.7%), with 36.7% being isolated from patients in an Intensive Care Unit. As high as 29.8% of P. aeruginosa and 73.0% of A. baumannii isolates were not susceptible to at least a carbapenem, whereas the majority of Enterobacteriaceae (97.2%) were susceptible to all carbapenems. Respective MIC(50)/MIC(90) values (MICs for 50% and 90% of the organisms, respectively) of doripenem, imipenem and meropenem were: 0.38/8, 1.5/32 and 0.38/16 mg/L for P. aeruginosa; 0.023/0.094, 0.25/0.5 and 0.032/0.094 mg/L for Enterobacteriaceae; and 32/64, 32/128 and 32/64 mg/L for A. baumannii. Doripenem and meropenem had comparable activity against P. aeruginosa, both being more active than imipenem. All carbapenems were highly potent against Enterobacteriaceae, although imipenem demonstrated higher MIC values than doripenem and meropenem. The three carbapenems showed less activity against A. baumannii. The high prevalence of carbapenem resistance amongst important nosocomial pathogens (P. aeruginosa and A. baumannii) warrants rigorous infection control measures and appropriate antimicrobial use in the Asia-Pacific region.

  1. Comparative pharmacodynamics of four different carbapenems in combination with polymyxin B against carbapenem-resistant Acinetobacter baumannii.

    PubMed

    Lenhard, Justin R; Gall, Jonathan S; Bulitta, Jurgen B; Thamlikitkul, Visanu; Landersdorfer, Cornelia B; Forrest, Alan; Nation, Roger L; Li, Jian; Tsuji, Brian T

    2016-12-01

    The objective of this study was to determine the comparative pharmacodynamics of four different carbapenems in combination with polymyxin B (PMB) against carbapenem-resistant Acinetobacter baumannii isolates using time-kill experiments at two different inocula. Two A. baumannii strains (03-149-1 and N16870) with carbapenem minimum inhibitory concentrations (MICs) ranging from 8 to 64 mg/L were investigated in 48-h time-kill experiments using starting inocula of 10(6) CFU/mL and 10(8) CFU/mL. Concentration arrays of ertapenem, doripenem, meropenem and imipenem at 0.25×, 0.5×, 1×, 1.5× and 2× published maximum serum concentration (Cmax) values (Cmax concentrations of 12, 21, 48 and 60 mg/L, respectively) were investigated in the presence of 1.5 mg/L PMB. Use of carbapenems without PMB resulted in drastic re-growth. All carbapenem combinations were able to achieve a ≥3 log10 CFU/mL reduction by 4 h against both strains at 10(6) CFU/mL, whereas maximum reductions against strain 03-149-1 at 10(8) CFU/mL were 1.0, 3.2, 2.2 and 3.3 log10 CFU/mL for ertapenem, doripenem, meropenem and imipenem, respectively. None of the combinations were capable of reducing 10(8) CFU/mL of N16870 by ≥2 log10 CFU/mL. Ertapenem combinations consistently displayed the least activity, whereas doripenem, meropenem and imipenem combinations had similar activities that were poorly predicted by carbapenem MICs. As doripenem, meropenem, or imipenem displayed similar pharmacodyanmics in combination, the decision of which carbapenem to use in combination with PMB may be based on toxicodynamic profiles if drastic discordance in MICs is not present.

  2. Pharmacokinetics and brain penetration of carbapenems in mice.

    PubMed

    Matsumoto, Kazuaki; Kurihara, Yuji; Kuroda, Yuko; Hori, Seiji; Kizu, Junko

    2016-05-01

    An adverse effect associated with the administration of carbapenems is central nervous system (CNS) toxicity, with higher brain concentrations of carbapenems being linked to an increased risk of seizures. However, the pharmacokinetics and brain penetration of carbapenems have not yet been examined. Thus, the aim of this in vivo investigation was to determine the pharmacokinetics and brain penetration of carbapenems in mice. Blood samples and brain tissue samples were obtained 10, 20, 30, 60, and 120 min after the subcutaneous administration of carbapenems (91 mg/kg). We obtained the following values for the pharmacokinetic parameters of carbapenems in mice: 1.20-1.71 L/h/kg for CLtotal/F, 1.41-2.03 h(-1) for Ke, 0.34-0.51 h for T1/2, 0.66-0.95 L/kg for Vss/F, 0.49-0.73 h for MRT, 83.46-110.58 μg/mL for Cmax, plasma, and 0.28-0.83 μg/g for Cmax, brain tissue. The AUC0-∞ of the carbapenems tested in plasma were in the following order: doripenem > meropenem > biapenem > imipenem, and in brain tissue were: imipenem > doripenem > meropenem > biapenem. The degrees of brain tissue penetration, defined as the AUC0-∞, brain tissue/fAUC0-∞, plasma ratio, were 0.016 for imipenem, 0.004 for meropenem, 0.002 for biapenem, and 0.008 for doripenem. The results of the present study demonstrated that, of the carbapenems examined, imipenem penetrated brain tissue to the greatest extent.

  3. SME-3, a novel member of the Serratia marcescens SME family of carbapenem-hydrolyzing beta-lactamases.

    PubMed

    Queenan, Anne Marie; Shang, Wenchi; Schreckenberger, Paul; Lolans, Karen; Bush, Karen; Quinn, John

    2006-10-01

    Imipenem-resistant Serratia marcescens isolates were cultured from a lung transplant patient given multiple antibiotics over several months. The strains expressed SME-3, a beta-lactamase of the rare SME carbapenem-hydrolyzing family. SME-3 differed from SME-1 by a single amino acid substitution of tyrosine for histidine at position 105, but the two beta-lactamases displayed similar hydrolytic profiles.

  4. In vitro prevention of Pseudomonas aeruginosa early biofilm formation with antibiotics used in cystic fibrosis patients.

    PubMed

    Fernández-Olmos, Ana; García-Castillo, María; Maiz, Luis; Lamas, Adelaida; Baquero, Fernando; Cantón, Rafael

    2012-08-01

    The ability of antibiotics used in bronchopulmonary infections in cystic fibrosis (CF) patients to prevent Pseudomonas aeruginosa early biofilm formation was studied using a biofilm microtitre assay with 57 non-mucoid P. aeruginosa isolates (44 first colonisers and 13 recovered during the initial intermittent colonisation stage) obtained from 35 CF patients. Minimum biofilm inhibitory concentrations (BICs) of levofloxacin, ciprofloxacin, imipenem, ceftazidime, tobramycin, colistin and azithromycin were determined by placing a peg lid with a formed biofilm onto microplates containing antibiotics. A modification of this protocol consisting of antibiotic challenge during biofilm formation was implemented in order to determine the biofilm prevention concentration (BPC), i.e. the minimum concentration able to prevent biofilm formation. The lowest BPCs were for fluoroquinolones, tobramycin and colistin and the highest for ceftazidime and imipenem. The former antibiotics had BPCs identical to or only slightly higher than their minimum inhibitory concentrations (MICs) determined by standard Clinical and Laboratory Standards Institute (CLSI) microdilution and were also active on formed biofilms as reflected by their low BIC values. In contrast, ceftazidime and imipenem were less effective for prevention of biofilm formation and on formed biofilms. In conclusion, the new BPC parameter determined in non-mucoid P. aeruginosa isolates recovered during early colonisation stages in CF patients supports early aggressive antimicrobial treatment guidelines in first P. aeruginosa-colonised CF patients.

  5. Outbreak Caused by blaOXA-72-Producing Acinetobacter baumannii ST417 Detected in Clinical and Environmental Isolates.

    PubMed

    Tamayo-Legorreta, Elsa; Turrubiartes-Martínez, Edgar; Garza-Ramos, Ulises; Niño-Moreno, Perla; Barrios, Humberto; Sánchez-Pérez, Alejandro; Reyna-Flores, Fernando; Tovar-Oviedo, Juana; Magaña-Aquino, Martin; Cevallos, Miguel Angel; Silva-Sanchez, Jesus

    2016-03-01

    We characterized an outbreak of imipenem-resistant Acinetobacter baumannii with clinical and environmental isolates from a tertiary care hospital in San Luis Potosi, Mexico. During a 4-month period, a total of 32 nonrepetitive imipenem-resistant clinical isolates of A. baumannii were collected. All isolates were susceptible to colistin and tigecycline and resistant to cefepime, ceftazidime, ceftriaxone, imipenem, and meropenem. Genotyping by pulsed-field gel electrophoresis showed a major clone (A). Multilocus sequence type (MLST) analysis was performed, revealing sequence type (ST) 417 (ST417) and 208 (ST208). The blaIMP-, blaVIM-, blaGIM-, blaSIM-, blaNDM-type, and blaOXA-type (blaOXA-23-like, blaOXA-24-like, blaOXA-51-like, and blaOXA-58-like) genes were screened and showed that the blaOXA-51-like and blaOXA-24-like genes were present in all isolates. Sequencing and southern hybridization were performed, confirming the presence of the blaOXA-72 gene and its plasmid-borne nature. In addition, the blaOXA-72-XerC/XerD-like association was identified. These findings indicate that a clonal spread of blaOXA-72-producing A. baumannii ST417 had occurred throughout the hospital. The ST417 corresponded with a previous ST described in the United States.

  6. MIC score, a new tool to compare bacterial susceptibility to antibiotics application to the comparison of susceptibility to different penems of clinical strains of Pseudomonas aeruginosa.

    PubMed

    Bretonnière, Cédric; Maitte, Adeline; Caillon, Jocelyne; Potel, Gilles; Boutoille, David; Jacqueline, Cédric; Guitton, Christophe

    2016-11-01

    This study aimed to compare the susceptibility to carbapenems (imipenem, meropenem and doripenem) of clinical strains of Pseudomonas aeruginosa. It also studied whether susceptibility to imipenem or meropenem could predict, reliably, susceptibility to doripenem. Pseudomonal strains were collected from respiratory specimens, half of them from cystic fibrosis patients. MICs were determined according to European Committee on Antimicrobial Susceptibility Testing recommendations. Carbapenems were compared according to the susceptible, intermediate or resistant categories. A new approach also allowed comparing these carbapenems in a 'MIC score' taking into account the differences in breakpoints between drugs. One hundred thirty-nine strains were studied. They were found to be statistically more susceptible to meropenem than to the two other drugs. However, this difference was small: less than one dilution between the agents. This study also highlighted a significant correlation between susceptibility to penems taken in pairs. However, susceptibility to imipenem or meropenem did not reliably predict susceptibility to doripenem. Despite potential differences in resistance mechanisms, the Pseudomonas aeruginosa strains showed close susceptibility to three carbapenems. This was true for both cystic fibrosis patients and others. However, there were variations between strains. That justifies MICs to be determined for each of the three penems. This might be useful in case of elevated MICs and/or for potentially difficult-to-treat infections such as pneumonia in patients with cystic fibrosis patients.

  7. Investigation of VIM, IMP, NDM-1, KPC AND OXA-48 enzymes in Enterobacteriaceae strains.

    PubMed

    Demir, Yelda; Zer, Yasemin; Karaoglan, Ilkay

    2015-05-01

    Gram-negative bacteria especially Enterobacteriaceae species have become an increasing etiologic agent of nosocomial infections. The development of resistance to carbapenems have become an increasing problem in the treatment of nosocomial infections. Especially carbapenamases are common for Enterobacteriaceae strains. This study was performed to detect the types of carbapenemases in Enterobacteriaceae strains isolated from various clinical samples. Enterobacteriaceae species were isolated from urine, blood, tracheal aspirates, wound, and other respiratory samples. Susceptibility of isolates to imipenem, meropenem and ertapenem was tested. Carbapenemase genes were studied using HyplexSuperBug ID kit. VIM (1-13), IMP (1-22), NDM-1, KPC(1-10) and OXA-48 genes were investigated. Ninety-five isolates of Enterobacteriaceae spp. were included in the study. Sixty isolates were resistant to imipenem, meropenem and ertapenem and 20 isolates were found resistant to imipenem or ertapenem while 15 were susceptible to all carbapenems. Among the isolates with carbapenem resistance, 57 were positive for one carbapenemase gene and susceptible isolates did not have carbapenemase gene. OXA-48 was found in 49 of the isolates (86%), NDM-1 in 6 (10.5%) isolates, VIM in 2 isolates. IMP and KPC gene loci were not identified. Carbapenemase genes play a crucial role in the development and spread of resistant strains.

  8. Pilot Screening to Determine Antimicrobial Synergies in a Multidrug-Resistant Bacterial Strain Library

    PubMed Central

    Kim, Si-Hyun; Park, Chulmin; Chun, Hye-Sun; Choi, Jae-Ki; Lee, Hyo-Jin; Cho, Sung-Yeon; Park, Sun Hee; Choi, Su-Mi; Choi, Jung-Hyun; Yoo, Jin-Hong

    2016-01-01

    With the rise in multidrug-resistant (MDR) bacterial infections, there has been increasing interest in combinations of ≥2 antimicrobial agents with synergistic effects. We established an MDR bacterial strain library to screen for in vitro antimicrobial synergy by using a broth microdilution checkerboard method and high-throughput luciferase-based bacterial cell viability assay. In total, 39 MDR bacterial strains, including 23 carbapenem-resistant gram-negative bacteria, 9 vancomycin-intermediate Staphylococcus aureus, and 7 vancomycin-resistant Enterococcus faecalis, were used to screen for potential antimicrobial synergies. Synergies were more frequently identified with combinations of imipenem plus trimethoprim–sulfamethoxazole for carbapenem-resistant Acinetobacter baumannii in the library. To verify this finding, we tested 34 A. baumannii clinical isolates resistant to both imipenem and trimethoprim–sulfamethoxazole by the checkerboard method. The imipenem plus trimethoprim–sulfamethoxazole combination showed synergy in the treatment of 21 (62%) of the clinical isolates. The results indicate that pilot screening for antimicrobial synergy in the MDR bacterial strain library could be valuable in the selection of combination therapeutic regimens to treat MDR bacterial infections. Further studies are warranted to determine whether this screening system can be useful to screen for the combined effects of conventional antimicrobials and new-generation antimicrobials or nonantimicrobials. PMID:26974861

  9. Carbapenem susceptibility among Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae isolates obtained from patients in intensive care units in Taiwan in 2005, 2007, and 2009.

    PubMed

    Jean, Shio-Shin; Lee, Wen-Sen; Bai, Kuan-Jen; Yu, Kwok-Woon; Hsu, Chin-Wang; Yu, Kwok-Woon; Liao, Chun-Hsing; Chang, Feng-Yi; Ko, Wen-Chien; Wu, Jiunn-Jong; Chen, Yen-Hsu; Chen, Yao-Shen; Liu, Jien-Wei; Lu, Min-Chi; Liu, Cheng-Yi; Chen, Ray-Jade; Hsueh, Po-Ren

    2015-04-01

    To investigate the evolutionary trends in non-susceptibility of carbapenems against the isolates of Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae from patients hospitalized in intensive care units (ICUs) of major teaching hospitals throughout Taiwan during 2005-2009, we applied the breakpoints of MICs recommended by Clinical and Laboratory Standards Institute and European Committee on Antimicrobial Susceptibility Testing in 2013. Escalations in imipenem MIC levels for overall E. coli and E. cloacae isolates and extended-spectrum β-lactamase (ESBL)-producing K. pneumoniae isolates were noted during this period. The overall MIC levels against imipenem and meropenem for subgroups of ESBL producers of 3 Enterobacteriaceae species were significantly higher than those of respective overall groups in 2007 and 2009. Compared with meropenem, we found that significant evidence of imipenem MIC creep and evidence of extraordinarily high rates of non-susceptibility to ertapenem among isolates of 3 species in 2009 existed. The prominent rises in rates of ertapenem non-susceptibility for ESBL-producing E. coli and K. pneumoniae during 2005-2009 and rate of ESBL positivity for E. cloacae between 4 years were notably found. Based on our findings, ertapenem should be used cautiously in management of the ICU infections caused by these potentially ESBL-producing Enterobacteriaceae isolates in Taiwan.

  10. Biochemical characterization of a novel extended-spectrum beta-lactamase from Pseudomonas aeruginosa 802.

    PubMed

    Rejiba, Samia; Limam, Ferid; Belhadj, Cherifa; Belhadj, Omrane; Ben-Mahrez, Kamel

    2002-01-01

    Pseudomonas aeruginosa 802 was isolated at Rabta hospital in Tunis and was resistant to extended-spectrum cephalosporins and aztreonam. It produced a pI 7.6 extended-spectrum beta-lactamase (ESBL). The ESBL, named LBT 802, was purified to homogeneity by filtration on Sephadex G-75 followed by CM-Sepharose chromatography and high-performance liquid chromatography (HPLC) on a TSK-gel SP-5PW column. The LBT 802 enzyme had a molecular mass of 30 kDa. It showed a broad-substrate profile by hydrolyzing benzylpenicillin, ampicillin, cephalothin, cephaloridine, cefotaxime, ceftriaxone, and cefpirome but not ceftazidime, cefoxitin, imipenem, or aztreonam. The highest hydrolytic efficiency (Vmax/Km) was obtained for ampicillin, cephalothin, cephaloridine, and benzylpenicillin. Among extended-spectrum cephalosporins the best substrate was ceftriaxone followed by cefotaxime and cefpirome. LBT 802 activity was inhibited by clavulanic acid, sulbactam, imipenem, cefoxitin, and aztreonam. It showed its lowest Ki values for clavulanic acid, imipenem and sulbactam.

  11. Evaluation of the in vitro ocular toxicity of the fortified antibiotic eye drops prepared at the Hospital Pharmacy Departments.

    PubMed

    Fernández-Ferreiro, Anxo; González-Barcia, Miguel; Gil-Martínez, María; Santiago Varela, María; Pardo, María; Blanco-Méndez, José; Piñeiro-Ces, Antonio; Lamas Díaz, María Jesús; Otero-Espinar, Francisco J

    2016-09-01

    The use of parenteral antibiotic eye drop formulations with non-marketed compositions or concentrations, commonly called fortified antibiotic eye drops, is a common practice in Ophthalmology in the hospital setting. The aim of this study was to evaluate the in vitro ocular toxicity of the main fortified antibiotic eye drops prepared in the Hospital Pharmacy Departments. We have conducted an in vitro experimental study in order to test the toxicity of gentamicin, amikacin, cefazolin, ceftazidime, vancomycin, colistimethate sodium and imipenem-cilastatin eye drops; their cytotoxicity and acute tissue irritation have been evaluated. Cell-based assays were performed on human stromal keratocytes, using a cell-based impedance biosensor system [xCELLigence Real-Time System Cell Analyzer (RTCA)], and the Hen's Egg Test for the ocular irritation tests. All the eye drops, except for vancomycin and imipenem, have shown a cytotoxic effect dependent on concentration and time; higher concentrations and longer exposure times will cause a steeper decline in the population of stromal keratocytes. Vancomycin showed a major initial cytotoxic effect, which was reverted over time; and imipenem appeared as a non-toxic compound for stromal cells. The eye drops with the highest irritating effect on the ocular surface were gentamicin and vancomycin. Those antibiotic eye drops prepared at the Hospital Pharmacy Departments included in this study were considered as compounds potentially cytotoxic for the ocular surface; this toxicity was dependent on the concentration used.

  12. Absence of cross-reactivity to carbapenems in patients with delayed hypersensitivity to penicillins.

    PubMed

    Romano, A; Gaeta, F; Valluzzi, R L; Alonzi, C; Maggioletti, M; Zaffiro, A; Caruso, C; Quaratino, D

    2013-12-01

    Studies performed on subjects with IgE-mediated hypersensitivity to penicillins have demonstrated a 1% rate of cross-reactivity between penicillins and both imipenem and meropenem, while a single study found a 5.5% rate of cross-reactivity with imipenem/cilastatin in subjects with T-cell-mediated hypersensitivity to β-lactams, mostly penicillins. We studied 204 consecutive subjects with a well-demonstrated T-cell-mediated hypersensitivity to assess the cross-reactivity with carbapenems and the tolerability of such alternative β-lactams. All 204 subjects underwent skin tests with imipenem/cilastatin and meropenem; 130 of them were skin-tested also with ertapenem. Subjects with negative test results were challenged with these carbapenems. All subjects displayed negative skin tests to carbapenems and tolerated challenges. These data demonstrate the absence of clinically significant T-cell-mediated cross-reactivity between penicillins and carbapenems. Negative delayed-reading skin testing with carbapenems in individuals with documented T-cell-mediated hypersensitivity to penicillins correlates well with subsequent clinical tolerance of therapeutic doses of carbapenems.

  13. Biochemical Characterization of β-Lactamases from Mycobacterium abscessus Complex and Genetic Environment of the β-Lactamase-Encoding Gene.

    PubMed

    Ramírez, Ana; Ruggiero, Melina; Aranaga, Carlos; Cataldi, Angel; Gutkind, Gabriel; de Waard, Jacobus H; Araque, María; Power, Pablo

    2017-04-01

    The objectives of this study were to determine the kinetic parameters of purified recombinant BlaMab and BlaMmas by spectrophotometry, analyze the genetic environment of the blaMab and blaMmas genes in both species by polymerase chain reaction and sequencing, furthermore, in silico models of both enzymes in complex with imipenem were obtained by modeling tools. Our results showed that BlaMab and BlaMmas have a similar hydrolysis behavior, displaying high catalytic efficiencies toward penams, cephalothin, and nitrocefin; none of the enzymes are well inhibited by clavulanate. BlaMmas hydrolyzes imipenem at higher efficiency than cefotaxime and aztreonam. BlaMab and BlaMmas showed that their closest structural homologs are KPC-2 and SFC-1, which correlate to the mild carbapenemase activity toward imipenem observed at least for BlaMmas. They also seem to differ from other class A β-lactamases by the presence of a more flexible Ω loop, which could impact in the hydrolysis efficiency against some antibiotics. A -35 consensus sequence (TCGACA) and embedded at the 3' end of MAB_2874, which may constitute the blaMab and blaMmas promoter. Our results suggest that the resistance mechanisms in fast-growing mycobacteria could be probably evolving toward the production of β-lactamases that have improved catalytic efficiencies against some of the drugs commonly used for the treatment of mycobacterial infections, endangering the use of important drugs like the carbapenems.

  14. Emergence and nosocomial transmission of ampicillin-resistant enterococci.

    PubMed Central

    Boyce, J M; Opal, S M; Potter-Bynoe, G; LaForge, R G; Zervos, M J; Furtado, G; Victor, G; Medeiros, A A

    1992-01-01

    Between 1986 and 1988, the incidence of ampicillin-resistant enterococci increased sevenfold at a university-affiliated hospital. Forty-three patients acquired nosocomial infections with ampicillin-resistant enterococci, most of which were also resistant to mezlocillin, piperacillin, and imipenem. An analysis of plasmid and chromosomal DNAs of isolates revealed that the increase was due to an epidemic of 19 nosocomial infections that yielded closely related strains of Enterococcus faecium and to a significant increase in the incidence of nonepidemic, largely unrelated strains of ampicillin-resistant enterococci. The nonepidemic strains were identified as E. faecium, E. raffinosus, E. durans, and E. gallinarum. A logistic regression analysis revealed that patients with nonepidemic resistant strains were 16 times more likely than controls to have received preceding therapy with imipenem. In our institution, the increase in the incidence of ampicillin-resistant enterococci appears to be due to the selection of various strains of resistant enterococci by the use of imipenem and to the nosocomial transmission of E. faecium and E. raffinosus. Images PMID:1510390

  15. Prevalence of OXA-type β-lactamases among Acinetobacter baumannii isolates from Northwest of Iran.

    PubMed

    Sohrabi, Nasrollah; Farajnia, Safar; Akhi, Mohammad Taghi; Nahaei, Mohammad Reza; Naghili, Behrooz; Peymani, Amir; Amiri, Zohreh; Rezaee, Mohammad Ahangarzadeh; Saeedi, Nazli

    2012-08-01

    Carbapenems have been considered as last line antibiotics for treatment of multidrug-resistant (MDR) Acinetobacter baumannii but carbapenem resistant A. baumannii has been increased during the last decade in many parts of the world. OXA-type β-lactamase enzymes are the most common cause of carbapenem resistance in A. baumannii and presence of ISAba1 in upstream of these genes may increase the expression of these OXA genes. The aim of this study was to determine, for the first time, the antibiotic resistance pattern and prevalence of OXA type β-lactamases among nosocomial A. baumannii isolates from northwest of Iran. A total of 100 A. baumannii isolates were recovered from hospitalized patients in a university hospital in northwest of Iran. Sixty-two percent of isolates were resistant to imipenem. All isolates carried bla(OXA-51)-like gene. Among imipenem resistant isolates, 88.7% carried bla(OXA-23)-like, 1.6% carried bla(OXA-40)-like, and 3.2% had bla(OXA-58)-like resistance genes. Ninety percent of isolates contained ISAba1 element and in 74.2% of imipenem resistant isolates, ISAba1 was located in upstream of bla(OXA-23)-like. The results of this study demonstrated high prevalence of OXA-type carbapenemase among MDR A. bumanii in the Northwest of Iran.

  16. Determination of integron frequency by a polymerase chain reaction-restriction fragment length polymorphism method in multidrug-resistant Escherichia coli, which causes urinary tract infections.

    PubMed

    Fallah, Fatemeh; Karimi, Abdollah; Goudarzi, Mehdi; Shiva, Farideh; Navidinia, Masoumeh; Jahromi, Mana Hadipour; Sajadi Nia, Raheleh Sadat

    2012-12-01

    The purpose of this study was to determine the presence of integrons in Escherichia coli, which cause urinary tract infections, and to define the association between integrons and antimicrobial susceptibility. Susceptibility of 200 isolates from urine samples of patients suffering from urinary tract infections to 13 antibiotics was determined by the Kirby-Bauer disk diffusion method. The existence of class1 and 2 integrons in resistant isolates was assessed by polymerase chain reaction-restriction fragment length polymorphism and sequencing. Antibiotic resistance patterns were observed as follows: amoxicillin 78%, tetracycline 76.1%, co-trimoxazole 67.7%, cephalotin 60%, nalidixic acid 57.4%, chloramphenicol 49%, gentamicin 46.4%, ceftazidim 38.1%, ciprofloxacin 36.2%, nitrofurantoin 33.5%, amikacin 32.1%, norfloxacin 36.1%, and imipenem 27.1%. Of 200 isolates, 155 (77.5%) were multidrug resistant (MDR). The existence of integrons was confirmed in 50.3% of isolates. Three class 1 integron types, aadA2 being the most frequently found, and four class 2 integron types are described. Significant association between resistance to gentamicin, co-trimoxazole, cephalotin, ceftazidim, imipenem, chloramphenicol, and nalidixic acid with the existence of integrons was observed. Multidrug resistance suggests that the strategy for treatment of patients with E.coli infections needs to be revised. Furthermore, it was shown that integrons may be partly responsible for multidrug resistance. Imipenem and norfloxacin were the most effective antibiotics against isolates.

  17. Correlation between carbapenem consumption and resistance to carbapenems among Enterobacteriaceae isolates collected from patients with intra-abdominal infections at five medical centers in Taiwan, 2006-2010.

    PubMed

    Ho, Cheng-Mao; Ho, Mao-Wang; Liu, Yung-Ching; Toh, Han-Siong; Lee, Yu-Lin; Liu, Yuag-Meng; Huang, Chi-Chang; Lu, Po-Liang; Liu, Chun-Eng; Chen, Yen-Hsu; Ko, Wen-Chien; Tang, Hung-Jen; Yu, Kwok-Woon; Chen, Yao-Shen; Chuang, Yin-Ching; Wang, Jen-Hsien; Hsueh, Po-Ren

    2012-06-01

    We investigated the trend in resistance to carbapenems among isolates of Enterobacteriaceae that had been collected from patients with intra-abdominal infections at five medical centers in Taiwan from 2006 to 2010 and evaluated the correlation between resistance to carbapenems and consumption of said agents as part of the Study for Monitoring Antimicrobial Resistance Trends (SMART). During the study period, the usage of ertapenem and that of total carbapenems (ertapenem, imipenem, and meropenem) increased significantly from 6.13 to 13.38 defined daily doses per 1000 patient-days for ertapenem and from 20.43 to 34.25 defined daily doses per 1000 patient-days for total carbapenems. The most common species were Escherichia coli (n = 1095), Klebsiella spp. (n = 663), and Enterobacter spp. (n = 202). The susceptibility of all isolates to ertapenem and to imipenem varied during the study period. For ertapenem, the rates of nonsusceptibility ranged from 3.5% to 10.3% and those for imipenem ranged from 3.5% to 10.7%. Although the use of carbapenems increased during the study period, there was no marked increase in resistance to carbapenems. Continuous monitoring of resistance trends is necessary so that antimicrobial prescription policies can be adjusted and infection control intervention programs can be implemented.

  18. Carbapenem-resistant Serratia marcescens isolates producing Bush group 2f beta-lactamase (SME-1) in the United States: results from the MYSTIC Programme.

    PubMed

    Gales, A C; Biedenbach, D J; Winokur, P; Hacek, D M; Pfaller, M A; Jones, R N

    2001-02-01

    Two carbapenem (imipenem, meropenem)-resistant Serratia marcescens strains were isolated in the United States (Chicago, IL) through the 1999 MYSTIC (Meropenem Yearly Susceptibility Test Information Collection) Programme. The S. marcescens antimicrobial susceptible patterns were: susceptible to ceftriaxone, ceftazidime, and cefepime (MICs, < or = 0.25 microg/ml), and resistance to the carbapenems (imipenem and meropenem; MIC, > 32 microg/ml) and aztreonam (MIC, > = 16 microg/ml). Each S. marcescens isolate shared an identical epidemiologic type (ribotype and PFGE) and the outer membrane protein profile was also identical to those of the wild type susceptible strains from the same medical center. The PCR utilizing bla(sme-1) primers amplified a gene product that was identified as consistent with SME-1 after DNA sequencing. Imipenem and meropenem resistance due to production of carbapenem-hydrolyzing enzymes among clinical isolates is still very rare, but microbiology laboratories should be aware of these chromosomally encoded enzymes among class C beta-lactamases producing enteric bacilli such as S. marcescens and Enterobacter cloacae.

  19. Structure of GES-1 at Atomic Resolution: Insights Into the Evolution of Carbapenamase Activity in the Class a Extended-Spectrum Beta-Lactamases

    SciTech Connect

    Smith, C.A.; Caccamo, M.; Kantardjieff, K.A.; Vakulenko, S.; /Notre Dame U.

    2007-10-08

    The structure of the class A extended-spectrum {beta}-lactamase GES-1 from Klebsiella pneumoniae has been determined to 1.1 Angstrom resolution. GES-1 has the characteristic active-site disulfide bond of the carbapenemase family of {beta}-lactamases and has a structure that is very similar to those of other known carbapenemases, including NMC-A, SME-1 and KPC-2. Most residues implicated in the catalytic mechanism of this class of enzyme are present in the GES-1 active site, including Ser70, which forms a covalent bond with the carbonyl C atom of the {beta}-lactam ring of the substrate during the formation of an acyl-enzyme intermediate, Glu166, which is implicated as both the acylation and deacylation base, and Lys73, which is also implicated as the acylation base. A water molecule crucial to catalysis is observed in an identical location as in other class A {beta}-lactamases, interacting with the side chains of Ser70 and Glu166. One important residue, Asn170, also normally a ligand for the hydrolytic water, is missing from the GES-1 active site. This residue is a glycine in GES-1 and the enzyme is unable to hydrolyze imipenem. This points to this residue as being critically important in the hydrolysis of this class of {beta}-lactam substrate. This is further supported by flexible-docking studies of imipenem with in silico-generated Gly170Asn and Gly170Ser mutant GES-1 enzymes designed to mimic the active sites of imipenem-hydrolyzing point mutants GES-2 and GES-5.

  20. Novel Carbapenem-Hydrolyzing β-Lactamase, KPC-1, from a Carbapenem-Resistant Strain of Klebsiella pneumoniae

    PubMed Central

    Yigit, Hesna; Queenan, Anne Marie; Anderson, Gregory J.; Domenech-Sanchez, Antonio; Biddle, James W.; Steward, Christine D.; Alberti, Sebastian; Bush, Karen; Tenover, Fred C.

    2001-01-01

    A Klebsiella pneumoniae isolate showing moderate to high-level imipenem and meropenem resistance was investigated. The MICs of both drugs were 16 μg/ml. The β-lactamase activity against imipenem and meropenem was inhibited in the presence of clavulanic acid. The strain was also resistant to extended-spectrum cephalosporins and aztreonam. Isoelectric focusing studies demonstrated three β-lactamases, with pIs of 7.2 (SHV-29), 6.7 (KPC-1), and 5.4 (TEM-1). The presence of blaSHV and blaTEM genes was confirmed by specific PCRs and DNA sequence analysis. Transformation and conjugation studies with Escherichia coli showed that the β-lactamase with a pI of 6.7, KPC-1 (K. pneumoniae carbapenemase-1), was encoded on an approximately 50-kb nonconjugative plasmid. The gene, blaKPC-1, was cloned in E. coli and shown to confer resistance to imipenem, meropenem, extended-spectrum cephalosporins, and aztreonam. The amino acid sequence of the novel carbapenem-hydrolyzing β-lactamase, KPC-1, showed 45% identity to the pI 9.7 carbapenem-hydrolyzing β-lactamase, Sme-1, from Serratia marcescens S6. Hydrolysis studies showed that purified KPC-1 hydrolyzed not only carbapenems but also penicillins, cephalosporins, and monobactams. KPC-1 had the highest affinity for meropenem. The kinetic studies also revealed that clavulanic acid and tazobactam inhibited KPC-1. An examination of the outer membrane proteins of the parent K. pneumoniae strain demonstrated that the strain does not express detectable levels of OmpK35 and OmpK37, although OmpK36 is present. We concluded that carbapenem resistance in K. pneumoniae strain 1534 is mainly due to production of a novel Bush group 2f, class A, carbapenem-hydrolyzing β-lactamase, KPC-1, although alterations in porin expression may also play a role. PMID:11257029

  1. Crystal Structures of Covalent Complexes of [beta]-Lactam Antibiotics with Escherichia coli Penicillin-Binding Protein 5: Toward an Understanding of Antibiotic Specificity

    SciTech Connect

    Nicola, George; Tomberg, Joshua; Pratt, R.F.; Nicholas, Robert A.; Davies, Christopher

    2010-12-07

    Penicillin-binding proteins (PBPs) are the molecular targets for the widely used {beta}-lactam class of antibiotics, but how these compounds act at the molecular level is not fully understood. We have determined crystal structures of Escherichia coli PBP 5 as covalent complexes with imipenem, cloxacillin, and cefoxitin. These antibiotics exhibit very different second-order rates of acylation for the enzyme. In all three structures, there is excellent electron density for the central portion of the {beta}-lactam, but weak or absent density for the R1 or R2 side chains. Areas of contact between the antibiotics and PBP 5 do not correlate with the rates of acylation. The same is true for conformational changes, because although a shift of a loop leading to an electrostatic interaction between Arg248 and the {beta}-lactam carboxylate, which occurs completely with cefoxitin and partially with imipenem and is absent with cloxacillin, is consistent with the different rates of acylation, mutagenesis of Arg248 decreased the level of cefoxitin acylation only 2-fold. Together, these data suggest that structures of postcovalent complexes of PBP 5 are unlikely to be useful vehicles for the design of new covalent inhibitors of PBPs. Finally, superimposition of the imipenem-acylated complex with PBP 5 in complex with a boronic acid peptidomimetic shows that the position corresponding to the hydrolytic water molecule is occluded by the ring nitrogen of the {beta}-lactam. Because the ring nitrogen occupies a similar position in all three complexes, this supports the hypothesis that deacylation is blocked by the continued presence of the leaving group after opening of the {beta}-lactam ring.

  2. Variability of cutaneous and nasal population levels between patients colonized and infected by multidrug-resistant bacteria in two Brazilian intensive care units

    PubMed Central

    Nicoli, Jacques R; Oliveira, Adriana

    2015-01-01

    Objective: To compare cutaneous and nasal population levels between patients colonized and infected by multidrug-resistant organisms in two intensive care units. Methods: A prospective cohort study was performed in adult intensive care units of two hospitals in Belo Horizonte, Brazil (April 2012 to February 2013). Clinical and demographic data were first collected by reviewing patients’ charts. Then, samples collected with nasal, groin, and perineum swabs were cultivated in selective media for 48 h at 37°C. After isolation, determination of antimicrobial susceptibility and biochemical identification were performed. Results: A total of 53 cases of colonization were observed by the following bacteria in decreasing frequencies: imipenem-resistant Acinetobacter baumannii (50.9%), vancomycin-resistant Enterococcus faecalis (43.4%), extended-spectrum beta-lactamase–producing Klebsiella pneumoniae (37.7%), imipenem-resistant Pseudomonas aeruginosa (32.1%), oxacillin-resistant Staphylococcus aureus (7.5%), and imipenem-resistant Klebsiella pneumoniae (5.7%). Among these colonization cases, 26 (49.0%) were followed by infection with bacteria phenotypically similar to those of the colonization. A relation between high population levels of colonization by most of the multidrug-resistant organisms at anatomical sites and a subsequent infection was observed. After colonization/infection, bacterial population levels decreased progressively and spontaneously until disappearance by day 45 in all the anatomical sites and for all the multidrug-resistant organisms. Conclusion: There was a correlation between high population levels of colonization by multidrug-resistant organisms at anatomical sites and a subsequent infection. Reduction in multidrug-resistant organism populations after colonization at anatomical sites could be a preventive measure to reduce evolution to infection as well as transmission of these bacteria between patients in intensive care unit. PMID:26770762

  3. Cefotaxime and Amoxicillin-Clavulanate Synergism against Extended-Spectrum-β-Lactamase-Producing Escherichia coli in a Murine Model of Urinary Tract Infection

    PubMed Central

    Rossi, B.; Soubirou, J. F.; Chau, F.; Massias, L.; Dion, S.; Lepeule, R.; Fantin, B.

    2015-01-01

    We investigated the efficacies of cefotaxime (CTX) and amoxicillin (AMX)-clavulanate (CLA) (AMC) against extended-spectrum-β-lactamase (ESBL)-producing Escherichia coli in vitro and in a murine model of urinary tract infection (UTI). MICs, the checkerboard dilution method, and time-kill curves were used to explore the in vitro synergism between cefotaxime and amoxicillin-clavulanate against two isogenic E. coli strains—CFT073-RR and its transconjugant, CFT073-RR Tc blaCTX-M-15—harboring a blaCTX-M-15 plasmid and a blaOXA-1 plasmid. For in vivo experiments, mice were separately infected with each strain and treated with cefotaxime, amoxicillin, and clavulanate, alone or in combination, or imipenem, using therapeutic regimens reproducing time of free-drug concentrations above the MIC (fT≥MIC) values close to that obtained in humans. MICs of amoxicillin, cefotaxime, and imipenem were 4/>1,024, 0.125/1,024, and 0.5/0.5 mg/liter, for CFT073-RR and CFT073-RR Tc blaCTX-M-15, respectively. The addition of 2 mg/liter of clavulanate (CLA) restored the susceptibility of CFT073-RR Tc blaCTX-M-15 to CTX (MICs of the CTX-CLA combination, 0.125 mg/liter). The checkerboard dilution method and time-kill curves confirmed an in vitro synergy between amoxicillin-clavulanate and cefotaxime against CFT073-RR Tc blaCTX-M-15. In vivo, this antibiotic combination was similarly active against both strains and as effective as imipenem. In conclusion, the cefotaxime and amoxicillin-clavulanate combination appear to be an effective, easy, and already available alternative to carbapenems for the treatment of UTI due to CTX-M-producing E. coli strains. PMID:26525800

  4. Cefotaxime and Amoxicillin-Clavulanate Synergism against Extended-Spectrum-β-Lactamase-Producing Escherichia coli in a Murine Model of Urinary Tract Infection.

    PubMed

    Rossi, B; Soubirou, J F; Chau, F; Massias, L; Dion, S; Lepeule, R; Fantin, B; Lefort, A

    2015-11-02

    We investigated the efficacies of cefotaxime (CTX) and amoxicillin (AMX)-clavulanate (CLA) (AMC) against extended-spectrum-β-lactamase (ESBL)-producing Escherichia coli in vitro and in a murine model of urinary tract infection (UTI). MICs, the checkerboard dilution method, and time-kill curves were used to explore the in vitro synergism between cefotaxime and amoxicillin-clavulanate against two isogenic E. coli strains-CFT073-RR and its transconjugant, CFT073-RR Tc bla(CTX-M-15)-harboring a bla(CTX-M-15) plasmid and a bla(OXA-1) plasmid. For in vivo experiments, mice were separately infected with each strain and treated with cefotaxime, amoxicillin, and clavulanate, alone or in combination, or imipenem, using therapeutic regimens reproducing time of free-drug concentrations above the MIC (fT≥MIC) values close to that obtained in humans. MICs of amoxicillin, cefotaxime, and imipenem were 4/>1,024, 0.125/1,024, and 0.5/0.5 mg/liter, for CFT073-RR and CFT073-RR Tc bla(CTX-M-15), respectively. The addition of 2 mg/liter of clavulanate (CLA) restored the susceptibility of CFT073-RR Tc bla(CTX-M-15) to CTX (MICs of the CTX-CLA combination, 0.125 mg/liter). The checkerboard dilution method and time-kill curves confirmed an in vitro synergy between amoxicillin-clavulanate and cefotaxime against CFT073-RR Tc bla(CTX-M-15). In vivo, this antibiotic combination was similarly active against both strains and as effective as imipenem. In conclusion, the cefotaxime and amoxicillin-clavulanate combination appear to be an effective, easy, and already available alternative to carbapenems for the treatment of UTI due to CTX-M-producing E. coli strains.

  5. Crystal structures of covalent complexes of β-lactam antibiotics with Escherichia coli penicillin-binding protein 5: toward an understanding of antibiotic specificity.

    PubMed

    Nicola, George; Tomberg, Joshua; Pratt, R F; Nicholas, Robert A; Davies, Christopher

    2010-09-21

    Penicillin-binding proteins (PBPs) are the molecular targets for the widely used β-lactam class of antibiotics, but how these compounds act at the molecular level is not fully understood. We have determined crystal structures of Escherichia coli PBP 5 as covalent complexes with imipenem, cloxacillin, and cefoxitin. These antibiotics exhibit very different second-order rates of acylation for the enzyme. In all three structures, there is excellent electron density for the central portion of the β-lactam, but weak or absent density for the R1 or R2 side chains. Areas of contact between the antibiotics and PBP 5 do not correlate with the rates of acylation. The same is true for conformational changes, because although a shift of a loop leading to an electrostatic interaction between Arg248 and the β-lactam carboxylate, which occurs completely with cefoxitin and partially with imipenem and is absent with cloxacillin, is consistent with the different rates of acylation, mutagenesis of Arg248 decreased the level of cefoxitin acylation only 2-fold. Together, these data suggest that structures of postcovalent complexes of PBP 5 are unlikely to be useful vehicles for the design of new covalent inhibitors of PBPs. Finally, superimposition of the imipenem-acylated complex with PBP 5 in complex with a boronic acid peptidomimetic shows that the position corresponding to the hydrolytic water molecule is occluded by the ring nitrogen of the β-lactam. Because the ring nitrogen occupies a similar position in all three complexes, this supports the hypothesis that deacylation is blocked by the continued presence of the leaving group after opening of the β-lactam ring.

  6. Antimicrobial Susceptibilities of Aerobic and Facultative Gram-Negative Bacilli from Intra-abdominal Infections in Patients from Seven Regions in China in 2012 and 2013.

    PubMed

    Zhang, Hui; Yang, Qiwen; Liao, Kang; Ni, Yuxing; Yu, Yunsong; Hu, Bijie; Sun, Ziyong; Huang, Wenxiang; Wang, Yong; Wu, Anhua; Feng, Xianju; Luo, Yanping; Hu, Zhidong; Chu, Yunzhuo; Chen, Shulan; Cao, Bin; Su, Jianrong; Gui, Bingdong; Duan, Qiong; Zhang, Shufang; Shao, Haifeng; Kong, Haishen; Badal, Robert E; Xu, Yingchun

    2015-10-19

    To evaluate the antimicrobial susceptibility of Gram-negative bacilli that caused hospital-acquired and community-acquired intra-abdominal infections (IAIs) in China between 2012 and 2013, we determined the susceptibilities to 12 antimicrobials and the extended-spectrum β-lactamase (ESBL) statuses of 3,540 IAI isolates from seven geographic areas in China in a central laboratory using CLSI broth microdilution and interpretive standards. Most infections were caused by Escherichia coli (46.3%) and Klebsiella pneumoniae (19.7%). Rates of ESBL-producing E. coli (P = 0.031), K. pneumoniae (P = 0.017), and Proteus mirabilis (P = 0.004) were higher in hospital-acquired IAIs than in community-acquired IAIs. Susceptibilities of enterobacteriaceae to ertapenem, amikacin, piperacillin-tazobactam, and imipenem were 71.3% to 100%, 81.3% to 100%, 64.7% to 100%, and 83.1% to 100%, respectively, but imipenem was ineffective against P. mirabilis (<20%). Although most ESBL-positive hospital-acquired isolates were resistant to third- and fourth-generation cephalosporins, the majority were susceptible to cefoxitin (47.9% to 83.9%). Susceptibilities of ESBL-positive isolates to ampicillin-sulbactam (<10%) were low, whereas susceptibilities to ciprofloxacin (0% to 54.6%) and levofloxacin (0% to 63.6%) varied substantially. The prevalences of cephalosporin-susceptible E. coli and K. pneumoniae were higher in the northeastern and southern regions than in the central and eastern regions, reflecting the ESBL-positive rates in these areas, and were lowest in the Jiangsu-Zhejiang (Jiang-Zhe) area where the rates of carbapenem resistance were also highest. Ertapenem, amikacin, piperacillin-tazobactam, and imipenem are the most efficacious antibiotics for treating IAIs in China, especially those caused by E. coli or K. pneumoniae. Resistance to cephalosporins and carbapenems is more common in the Jiang-Zhe area than in other regions in China.

  7. Crystal structures of covalent complexes of β-lactam antibiotics with E. coli penicillin-binding protein 5: toward an understanding of antibiotic specificity†

    PubMed Central

    Nicola, George; Tomberg, Joshua; Pratt, R. F.; Nicholas, Robert A.; Davies, Christopher

    2010-01-01

    Penicillin-binding proteins (PBPs) are the molecular target for the widely used β-lactam class of antibiotics, but how these compounds act at the molecular level is not fully understood. We have determined crystal structures of E. coli PBP5 as covalent complexes with imipenem, cloxacillin and cefoxitin. These antibiotics exhibit very different second order rates of acylation for the enzyme. In all three structures, there is excellent electron density for the central portion of the β-lactam, but weak or absent density for the R1 or R2 side chains. Areas of contact between the antibiotics and PBP 5 do not correlate with the rates of acylation. The same is true for conformational changes because although shift of a loop leading to an electrostatic interaction between Arg248 and the β-lactam carboxylate, which occurs completely with cefoxitin, partially with imipenem and is absent with cloxacillin, is consistent with the different rates of acylation, mutagenesis of Arg248 only decreased cefoxitin acylation two fold. Together, these data suggest that structures of post-covalent complexes of PBP 5 are unlikely to be useful vehicles for design of new covalent inhibitors of PBPs. Finally, superimposition of the imipenem-acylated complex with PBP5 in complex with a boronic acid peptidemimetic shows that the position corresponding to the hydrolytic water molecule is occluded by the ring nitrogen of the β-lactam. Since the ring nitrogen occupies a similar position in all three complexes, this supports the hypothesis that deacylation is blocked by the continued presence of the leaving group after opening of the β-lactam ring. PMID:20726582

  8. Carbapenem susceptibility testing errors using three automated systems, disk diffusion, Etest, and broth microdilution and carbapenem resistance genes in isolates of Acinetobacter baumannii-calcoaceticus complex.

    PubMed

    Markelz, Ana Elizabeth; Mende, Katrin; Murray, Clinton K; Yu, Xin; Zera, Wendy C; Hospenthal, Duane R; Beckius, Miriam L; Calvano, Tatjana; Akers, Kevin S

    2011-10-01

    The Acinetobacter baumannii-calcoaceticus complex (ABC) is associated with increasing carbapenem resistance, necessitating accurate resistance testing to maximize therapeutic options. We determined the accuracy of carbapenem antimicrobial susceptibility tests for ABC isolates and surveyed them for genetic determinants of carbapenem resistance. A total of 107 single-patient ABC isolates from blood and wound infections from 2006 to 2008 were evaluated. MICs of imipenem, meropenem, and doripenem determined by broth microdilution (BMD) were compared to results obtained by disk diffusion, Etest, and automated methods (the MicroScan, Phoenix, and Vitek 2 systems). Discordant results were categorized as very major errors (VME), major errors (ME), and minor errors (mE). DNA sequences encoding OXA beta-lactamase enzymes (bla(OXA-23-like), bla(OXA-24-like), bla(OXA-58-like), and bla(OXA-51-like)) and metallo-β-lactamases (MBLs) (IMP, VIM, and SIM1) were identified by PCR, as was the KPC2 carbapenemase gene. Imipenem was more active than meropenem and doripenem. The percentage of susceptibility was 37.4% for imipenem, 35.5% for meropenem, and 3.7% for doripenem. Manual methods were more accurate than automated methods. bla(OXA-23-like) and bla(OXA-24-like) were the primary resistance genes found. bla(OXA-58-like), MBLs, and KPC2 were not present. Both automated testing and manual testing for susceptibility to doripenem were very inaccurate, with VME rates ranging between 2.8 and 30.8%. International variability in carbapenem breakpoints and the absence of CLSI breakpoints for doripenem present a challenge in susceptibility testing.

  9. Genetic and Structural Insights into the Dissemination Potential of the Extremely Broad-Spectrum Class A β-Lactamase KPC-2 Identified in an Escherichia coli Strain and an Enterobacter cloacae Strain Isolated from the Same Patient in France▿

    PubMed Central

    Petrella, Stephanie; Ziental-Gelus, Nathalie; Mayer, Claudine; Renard, Murielle; Jarlier, Vincent; Sougakoff, Wladimir

    2008-01-01

    Two clinical strains of Escherichia coli (2138) and Enterobacter cloacae (7506) isolated from the same patient in France and showing resistance to extended-spectrum cephalosporins and low susceptibility to imipenem were investigated. Both strains harbored the plasmid-contained blaTEM-1 and blaKPC-2 genes. blaKLUC-2, encoding a mutant of the chromosomal β-lactamase of Kluyvera cryocrescens, was also identified at a plasmid location in E. cloacae 7506, suggesting the ISEcp1-assisted escape of blaKLUC from the chromosome. Determination of the KPC-2 structure at 1.6 Å revealed that the binding site was occupied by the C-terminal (C-ter) residues coming from a symmetric KPC-2 monomer, with the ultimate C-ter Glu interacting with Ser130, Lys234, Thr235, and Thr237 in the active site. This mode of binding can be paralleled to the inhibition of the TEM-1 β-lactamase by the inhibitory protein BLIP. Determination of the 1.23-Å structure of a KPC-2 mutant in which the five C-ter residues were deleted revealed that the catalytic site was filled by a citrate molecule. Structure analysis and docking simulations with cefotaxime and imipenem provided further insights into the molecular basis of the extremely broad spectrum of KPC-2, which behaves as a cefotaximase with significant activity against carbapenems. In particular, residues 104, 105, 132, and 167 draw a binding cavity capable of accommodating both the aminothiazole moiety of cefotaxime and the 6α-hydroxyethyl group of imipenem, with the binding of the former drug being also favored by a significant degree of freedom at the level of the loop at positions 96 to 105 and by an enlargement of the binding site at the end of strand β3. PMID:18625772

  10. Impact of carbapenem heteroresistance among clinical isolates of invasive Escherichia coli in Chongqing, southwestern China.

    PubMed

    Sun, J D; Huang, S F; Yang, S S; Pu, S L; Zhang, C M; Zhang, L P

    2015-05-01

    Although heteroresistance is common in a wide range of microorganisms, carbapenem heteroresistance among invasive Escherichia coli infections has not been reported. The objective of this study was to evaluate the clinical significance of carbapenem heteroresistance and to identify risk factors for its acquisition. A case-control study was conducted at a 3200-bed teaching hospital in Chongqing, southwestern China. Successive and non-duplicate nosocomial E. coli isolates (n = 332) were obtained from July 2011 to June 2013. Bloodstream isolates made up 50.6% of the strains collected. The rates of heteroresistance were 25.0% to imipenem, 17.2% to ertapenem, and 3.9% to meropenem. The population analysis profile revealed the presence of subpopulations with higher carbapenem resistance, showing MICs ranging from 2.0-128.0mg/L. Male gender, invasive intervention, antibiotic use and bacterial extended-spectrum β-lactamase (ESBL) production contributed to invasive infections by carbapenem-heteroresistant E. coli (CHEC). The production of ESBL was identified as the common independent risk factor for heteroresistance to both ertapenem and imipenem. Pulsed-field gel electrophoresis revealed clonal diversity among the CHEC isolates. Most importantly, characterization of two successive E. coli strains isolated from the same patient indicated that carbapenem resistance evolved from heteroresistance. In conclusion, the high prevalence of heteroresistance to carbapenem among invasive E. coli merits great attention. Routine detection of ESBLs and the prudent use of imipenem and ertapenem are advocated. The early targeted intervention should be formulated to reduce CHEC infection and carbapenem resistance of E. coli.

  11. Antimicrobial Susceptibilities of Aerobic and Facultative Gram-Negative Bacilli from Intra-abdominal Infections in Patients from Seven Regions in China in 2012 and 2013

    PubMed Central

    Zhang, Hui; Yang, Qiwen; Liao, Kang; Ni, Yuxing; Yu, Yunsong; Hu, Bijie; Sun, Ziyong; Huang, Wenxiang; Wang, Yong; Wu, Anhua; Feng, Xianju; Luo, Yanping; Hu, Zhidong; Chu, Yunzhuo; Chen, Shulan; Cao, Bin; Su, Jianrong; Gui, Bingdong; Duan, Qiong; Zhang, Shufang; Shao, Haifeng; Kong, Haishen; Badal, Robert E.

    2015-01-01

    To evaluate the antimicrobial susceptibility of Gram-negative bacilli that caused hospital-acquired and community-acquired intra-abdominal infections (IAIs) in China between 2012 and 2013, we determined the susceptibilities to 12 antimicrobials and the extended-spectrum β-lactamase (ESBL) statuses of 3,540 IAI isolates from seven geographic areas in China in a central laboratory using CLSI broth microdilution and interpretive standards. Most infections were caused by Escherichia coli (46.3%) and Klebsiella pneumoniae (19.7%). Rates of ESBL-producing E. coli (P = 0.031), K. pneumoniae (P = 0.017), and Proteus mirabilis (P = 0.004) were higher in hospital-acquired IAIs than in community-acquired IAIs. Susceptibilities of enterobacteriaceae to ertapenem, amikacin, piperacillin-tazobactam, and imipenem were 71.3% to 100%, 81.3% to 100%, 64.7% to 100%, and 83.1% to 100%, respectively, but imipenem was ineffective against P. mirabilis (<20%). Although most ESBL-positive hospital-acquired isolates were resistant to third- and fourth-generation cephalosporins, the majority were susceptible to cefoxitin (47.9% to 83.9%). Susceptibilities of ESBL-positive isolates to ampicillin-sulbactam (<10%) were low, whereas susceptibilities to ciprofloxacin (0% to 54.6%) and levofloxacin (0% to 63.6%) varied substantially. The prevalences of cephalosporin-susceptible E. coli and K. pneumoniae were higher in the northeastern and southern regions than in the central and eastern regions, reflecting the ESBL-positive rates in these areas, and were lowest in the Jiangsu-Zhejiang (Jiang-Zhe) area where the rates of carbapenem resistance were also highest. Ertapenem, amikacin, piperacillin-tazobactam, and imipenem are the most efficacious antibiotics for treating IAIs in China, especially those caused by E. coli or K. pneumoniae. Resistance to cephalosporins and carbapenems is more common in the Jiang-Zhe area than in other regions in China. PMID:26482308

  12. Study on the resistance mechanism via outer membrane protein OprD2 and metal β-lactamase expression in the cell wall of Pseudomonas aeruginosa.

    PubMed

    Cai, Shuangqi; Chen, Yiqiang; Song, Dezhi; Kong, Jinliang; Wu, Yanbin; Lu, Huasong

    2016-11-01

    The aim of the present study was to evaluate the imipenem-resistant mechanism via the outer membrane protein (OMP) OprD2 and metal β-lactamase expression in the cell wall of Pseudomonas aeruginosa. The Pseudomonas aeruginosa was clinically separated and validated by VITEK-2 full-automatic bacteria analyzer. Drug resistance, sensitive antibiotics and minimum inhibitory concentration (MIC) were tested using the drug sensitivity analysis system. The phenotype positive strains of MBL genes were screened using the Kirby-Bauer diffusion method by adding metal ion-chelating agent EDTA on the imipenem susceptibility paper. IMP-1, VIM-1 and SPM metaloenzyme genes were tested by polymerase chain reaction (PCR)-telomeric repeat amplification protocol (TRAP). The OMP OprD2 genes were tested by PCR-TRAP, and the protein expression was tested using western blot analysis. The location of OMP OprD2 was confirmed using the sodium salicylate inhibition test. The results showed that 80 portions (40%) of MBL-positive strains were screened out of 200 specimens. Imipenem-resistant Pseudomonas aeruginosa (IRPA) and MIC values were significantly higher than quality control bacteria and control bacteria (P<0.05). A total of 35 cases with IMP-1 positive, 20 with VIM-1 positive, 16 with SPM positive, 5 with 2 positive genes and 4 with 3 positive genes were screened among MBL positive strains. A total of 150 portions (75%) of OprD2 deficiencies were screened from 200 specimens. The standard strains and sensitive strains showed OprD2 protein bands at 45 kDa while no OprD2 protein bands appeared in OprD2 deficiency strains. It was in accordance with gene detection. In conclusion, OMP OprD2 deficiency and MBL phenotype positivity may be important mechanisms of IRPA.

  13. Carbapenems and piperacillin/tazobactam for the treatment of bacteremia caused by extended-spectrum β-lactamase-producing Proteus mirabilis.

    PubMed

    Tsai, Hsih-Yeh; Chen, Yen-Hsu; Tang, Hung-Jen; Huang, Chi-Chang; Liao, Chun-Hsing; Chu, Fang-Yeh; Chuang, Yin-Ching; Sheng, Wang-Huei; Ko, Wen-Chien; Hsueh, Po-Ren

    2014-11-01

    This study was intended to delineate the role of carbapenems and piperacillin/tazobactam in treating bacteremia caused by extended-spectrum β-lactamase (ESBL)-producing Proteus mirabilis. We performed a multicenter and retrospective study of the patients with ESBL-producing P. mirabilis bacteremia. The outcomes of the patients treated by piperacillin/tazobactam or a carbapenem for at least 48 hours and the MICs of the prescribed drugs for these isolates were analyzed. Forty-seven patients with available clinical data were included. The overall 30-day mortality rate was 29.8%. All available isolates (n = 44) were susceptible to ertapenem, meropenem, and doripenem, and 95.6% were susceptible to piperacillin/tazobactam; however, only 11.4% of the isolates were susceptible to imipenem. Among the 3 patients infected with isolates exhibiting non-susceptibility to imipenem (MIC ≥2 mg/L) who were treated with imipenem, none died within 28 days. The 30-day (14.3% versus 23.1%, P = 0.65) or in-hospital (19.1% versus 30.8%, P = 0.68) mortality rate of 21 patients treated by a carbapenem was lower than that of 13 treated by piperacillin/tazobactam. However, among those treated by piperacillin/tazobactam, the mortality rate of those infected by the isolates with lower piperacillin/tazobactam MICs (≤0.5/4 mg/L) was lower than that of the isolates with MICs of ≥1/4 mg/L (0%, 0/7 versus 60%, 3/5; P = 0.045). ESBL-producing P. mirabilis bacteremia is associated with significant mortality, and carbapenem therapy could be regarded as the drugs of choice. The role of piperacillin/tazobactam, especially for the infections due to the isolates with an MIC ≤0.5/4 mg/L, warrants more clinical studies.

  14. High prevalence of methicillin resistant staphylococci strains isolated from surgical site infections in Kinshasa

    PubMed Central

    Iyamba, Jean-Marie Liesse; Wambale, José Mulwahali; Lukukula, Cyprien Mbundu; Takaisi-Kikuni, Ntondo za Balega

    2014-01-01

    Introduction Surgical site infections (SSIs) after surgery are usually caused by Staphylococcus aureus and coagulase-negative staphylococci (CNS). In low income countries, methicillin resistant Staphylococcus aureus (MRSA) and methicillin resistant coagulase-negative staphylococci (MR-CNS) surgical site infections are particularly associated with high treatment cost and remain a source of mortality and morbidity. This study aimed to determine the prevalence and the sensitivity to antibiotics of MRSA and MR-CNS isolated from SSIs. Methods Wound swabs were collected from 130 hospitalized surgical patients in two major hospitals of Kinshasa. S. aureus and CNS strains were identified by standard microbiological methods and latex agglutination test (Pastorex Staph-Plus). The antibiotic susceptibility of all staphylococcal strains was carried out using disk-diffusion method. Results Eighty nine staphylococcal strains were isolated. Out of 74 S. aureus and 15 CNS isolated, 47 (63.5%) and 9 (60%) were identified as MRSA and MR-CNS respectively. Among the MRSA strains, 47 strains (100%) were sensitive to imipenem, 39 strains (89%) to amoxycillin-clavulanic acid and 38 strains (81%) to vancomycin. All MR-CNS were sensitive to imipenem, amoxycillin-clavulanic acid and vancomycin. The isolated MRSA and MR-CNS strains showed multidrug resistance. They were both resistant to ampicillin, cotrimoxazole, erythromycin, clindamycin, ciprofloxacin, cefotaxime and ceftazidime. Conclusion The results of the present study showed a high prevalence of MRSA and MR-CNS. Imipenem, amoxycillin-clavulanic acid and vancomycin were the most active antibiotics. This study suggests that antibiotic surveillance policy should become national priority as MRSA and MR-CNS were found to be multidrug resistant. PMID:25478043

  15. Molecular epidemiology and antimicrobial resistance phenotypes of Acinetobacter baumannii isolated from patients in three hospitals in southern Vietnam.

    PubMed

    Tuan Anh, Nguyen; Nga, Tran Vu Thieu; Tuan, Huynh Minh; Tuan, Nguyen Si; Y, Dao Minh; Vinh Chau, Nguyen Van; Baker, Stephen; Duong, Ho Huynh Thuy

    2017-01-01

    Multidrug resistance in the nosocomial pathogen Acinetobacter baumannii limits therapeutic options and impacts on clinical care. Resistance against carbapenems, a group of last-resort antimicrobials for treating multidrug-resistant (MDR) A. baumannii infections, is associated with the expression (and over-expression) of carbapenemases encoded by the blaOXA genes. The aim of this study was to determine the prevalence of antimicrobial-resistant A. baumannii associated with infection in three hospitals in southern Vietnam and to characterize the genetic determinants associated with resistance against carbapenems. We recovered a total of 160 A. baumannii isolates from clinical samples collected in three hospitals in southern Vietnam from 2012 to 2014. Antimicrobial resistance was common; 119/160 (74 %) of isolates were both MDR and extensively drug resistant (XDR). High-level imipenem resistance (>32 µg ml-1) was determined for 109/117 (91.6 %) of the XDR imipenem-nonsusceptible organisms, of which the majority (86.7 %) harboured the blaOXA-51 and blaOXA-23 genes associated with an ISAba1 element. Multiple-locus variable number tandem repeat analysis segregated the 160 A. baumannii into 107 different multiple-locus variable number tandem repeat analysis types, which described five major clusters. The biggest cluster was a clonal complex composed mainly of imipenem-resistant organisms that were isolated from all three of the study hospitals. Our study indicates a very high prevalence of MDR/XDR A. baumannii causing clinically significant infections in hospitals in southern Vietnam. These organisms commonly harboured the blaOXA-23 gene with ISAba1 and were carbapenem resistant; this resistance phenotype may explain their continued selection and ongoing transmission within the Vietnamese healthcare system.

  16. Molecular Detection of Class-D OXA Carbapenemase Genes in Biofilm and Non-Biofilm Forming Clinical Isolates of Acinetobacter baumannii

    PubMed Central

    Azizi, Omid; Shakibaie, Mohammad Reza; Modarresi, Farzan; Shahcheraghi, Fereshteh

    2015-01-01

    Background: Emergence and spread of carbapenemase (blaOXA) genes in multidrug resistant Acinetobacter baumannii (MDR-AB) forming biofilm complicated treatment of the patients infected with this microorganism particularly in intensive care units (ICUs). Objectives: The current study aimed to determine the prevalence of molecular class-D OXA carbapenemase in biofilm and non-biofilm forming strains of MDR-AB. Materials and Methods: A total of 65 strains of MDR-AB were isolated from the patients hospitalized in the ICU of two hospitals in Kerman, Iran. The isolates were identified by conventional microbiological tests as well as API 20NE assay. Antibiotic susceptibility was carried out by disk diffusion method; minimum inhibitory concentration (MIC) of carbapenems was measured by E-test. The presence of blaOXA genes among the isolates were studied by duplex-polymerase chain reaction and application of appropriate primers. Biofilm formation was detected by microtiter plate method. Results: The isolates were highly resistant to ciprofloxacin, levofloxacin, piperacillin, nalidixic acid and third generation cephalosporins such as tigecycline (7%; n = 5) and colistin (13%; n = 8). Among the isolates, 77% (n = 50) exhibited high MIC (265μg/mL) for imipenem. Both the blaOXA-51 and blaOXA-23 like genes coexisted in all the isolates; while, blaOXA-24/40 like gene was only detected in 29 imipenem-resistant strains (P ≤ 0.05). The blaOXA-58 like gene was not detected among the isolated strains. Quantification of biofilm introduced 23 isolates (including blaOXA-24/40 strains) with efficient attachment to microtiter plate; while, those isolates without blaOXA-24/40, or imipenem-sensitive strains formed weak or no biofilm. Conclusions: Coexistence of the blaOXA-51, blaOXA-23 and blaOXA-24/40 like genes, along with formation of strong biofilm, in MDR-AB strains particularly with indiscriminate use of imipenem, complicated treatment of the patients infected with these bacteria in

  17. [In vitro sensitivity of Mycobacterium chelonae strains to various antimicrobial agents].

    PubMed

    Hernández García, A M; Arias, A; Felipe, A; Alvarez, R; Sierra, A

    1995-12-01

    The in vitro susceptibility of 32 Mycobacterium chelonae strains to 10 antimicrobial agents was determined. The sources of the different strains were: clinical samples from patients treated at the Hospital Universitario de Canarias and Hospital del Tórax (General and Chest facilities) and from environmental sources (water supply, sewage, swimming pools and the sea). The susceptibility tests were performed by a broth microdilution method (Mueller-Hinton Broth). The results showed amikacin as the most effective antimicrobial agent against M. chelonae isolates, then ofloxacin and cefoxitin. However no statistical difference was detected among them. The least effective was imipenem, followed by ciprofloxacin and norfloxacin.

  18. Effect of High N-Acetylcysteine Concentrations on Antibiotic Activity against a Large Collection of Respiratory Pathogens

    PubMed Central

    Landini, Giulia; Di Maggio, Tiziana; Sergio, Francesco; Docquier, Jean-Denis; Rossolini, Gian Maria

    2016-01-01

    The effect of high N-acetylcysteine (NAC) concentrations (10 and 50 mM) on antibiotic activity against 40 strains of respiratory pathogens was investigated. NAC compromised the activity of carbapenems (of mostly imipenem and, to lesser extents, meropenem and ertapenem) in a dose-dependent fashion. We demonstrated chemical instability of carbapenems in the presence of NAC. With other antibiotics, 10 mM NAC had no major effects, while 50 mM NAC sporadically decreased (ceftriaxone and aminoglycosides) or increased (penicillins) antibiotic activity. PMID:27736757

  19. First isolation of two colistin-resistant emerging pathogens, Brevundimonas diminuta and Ochrobactrum anthropi, in a woman with cystic fibrosis: a case report

    PubMed Central

    Menuet, Magalie; Bittar, Fadi; Stremler, Nathalie; Dubus, Jean-Christophe; Sarles, Jacques; Raoult, Didier; Rolain, Jean-Marc

    2008-01-01

    Introduction Cystic fibrosis afflicted lungs support the growth of many bacteria rarely implicated in other cases of human infections. Case presentation We report the isolation and identification, by 16S rRNA amplification and sequencing, of two emerging pathogens resistant to colistin, Brevundimonas diminuta and Ochrobactrum anthropi, in a 17-year-old woman with cystic fibrosis and pneumonia. The patient eventually responded well to a 2-week regime of imipenem and tobramycin. Conclusion Our results clearly re-emphasize the emergence of new colistin-resistant pathogens in patients with cystic fibrosis. PMID:19061488

  20. Klebsiella pneumoniae carrying bla NDM-1 gene in orthopedic practice.

    PubMed

    Gupta, Varsha; Bansal, Neha; Gupta, Ravi; Chander, Jagdish

    2014-09-01

    Emergence and spread of carbapenemases in Enterobacteriaceae is a cause of concern worldwide, the latest threat being New Delhi metallo-β-lactamase (NDM-1). This report is of an orthopedic case with fracture femur managed with internal fixation and bone grafting, who subsequently developed secondary infection with Klebsiella pneumoniae harboring bla NDM-1 gene. Minimum inhibitory concentration (MIC) of imipenem was ≥8 μg/ml by E-test, suggestive of carbapenemase production. Phenotypic and further genotypic detection confirmed the presence of bla NDM-1 gene. The isolate remained susceptible only to tigecycline, colistin, and polymyxin B.

  1. In vitro evaluation of a new drug combination against clinical isolates belonging to the Mycobacterium abscessus complex.

    PubMed

    Singh, S; Bouzinbi, N; Chaturvedi, V; Godreuil, S; Kremer, L

    2014-12-01

    The in vitro susceptibility profile to amikacin, linezolid, clarithromycin, imipenem, cefoxitin, clofazimine and tigecycline was established for 67 strains belonging to the Mycobacterium abscessus complex. Clofazimine and tigecycline were among the most effective drugs, prompting us to assess the effect of a clofazimine and tigecycline combination. Synergistic activity was found in 42% of the 19 isolates tested. The clinical impact of this new drug combination against the M. abscessus complex, as an alternative or sequential medication for the treatment of drug-resistant strains, remains to be addressed.

  2. Mycobacterium abscessus complex bacteremia due to prostatitis after prostate biopsy.

    PubMed

    Chen, Chung-Hua; Lin, Jesun; Lin, Jen-Shiou; Chen, Yu-Min

    2016-10-01

    We present the case of a 49-year-old man, who developed Mycobacterium abscessus complex (M. abscessus complex) bacteremia and prostatitis after prostate biopsy. The patient was successfully treated with amikacin with imipenem-cilastatin with clarithromycin. Infections caused by M. abscessus complex have been increasingly described as a complication associated with many invasive procedures. Invasive procedures might have contributed to the occurrence of the M. abscessus complex. Although M. abscessus complex infection is difficult to diagnose and treat, we should pay more attention to this kind of infection, and the correct treatment strategy will be achieved by physicians.

  3. Vertically acquired neonatal citrobacter brain abscess - case report and review of the literature.

    PubMed

    Agrawal, Deepak; Mahapatra, Ashok Kumar

    2005-02-01

    Vertically acquired citrobacter meningitis in the neonate is very rare and carries a very high mortality and morbidity. Overall, approximately 30% of neonates with Citrobacter meningitis die and 50% sustain some damage to the CNS. The authors describe a case of a newborn with Citrobacter koseri meningitis with multiple brain abscesses, with a successful outcome following multiple burr-hole aspirations and prolonged antibiotic therapy. An aggressive surgical approach combined with intravenous antibiotics (including imipenems, to which the organism is very sensitive) for a minimum of 4 weeks appears to improve the outcome of infection with this virulent organism.

  4. [Bacteriological profile and antibiotic treatment of postoperative peritonitis].

    PubMed

    Missaoui, K; Marzougui, Y; Kouka, J; Dhibi, Y; Hannachi, Z; Dziri, C; Houissa, M

    2014-01-01

    During the postoperative peritonitis (PPO) the main stay of treatment is the choice of probabilistic antibiotictherapy, it is also the main prognostic factor The aim of our study was to identify anappropriate antibiotic protocol to the current ecology of our unit. It was a retrospective study including 102 patients over a period of 09 years from 1 January 2003 to 3O November 2011. All of them are supported for the treatments off postoperative peritonitis in surgical intensive care unit of a service of general surgery a university hospital Charles Nicolle of Tunis. All bacteriological data (germs and sensitivity), and the terms of therapeutic modality for the empirical antibiotic therapy were listed. The incidence of PPO was Q90%.The average age of our patients was 57 +/- 18 years. The sex ratio was 1.08. One hundred and seven (107) microorganisms were isolated from 72 samples (44 microbial mono, 28 multi microbial). The frequency of gram-positive cocci (GPC) was 16.82%, the Gram-negative bacilli (BGN) was 82.2%. The Enterobacteriaceae have proved particularity resistant. Thus, the ampicillin resistance was 87.14%, that the C3G was 33.80%, the Piperacillin to Tazobactam combination, was 36.5% and that the association Ticarcillin-clavulanic acid was 43.6%. For non-fermenting BGN, Pseudomonas aeruginosa was sensitive to ticarcillin in 80% of cases, to ceftazidime in 66.6% of cases, PiperacillinTazobactam--in 71.43% of cases, imipenem in 85 72% of cases, colimycin in 100% of cases and Amiklin in 71.43% of cases. For CGP, enterococci were resistant to ampicillin in 50% of cases and vancomycin in 0% of cases. The majority of patients received triple antibiotic therapy (59.8%) or combination therapy (34.3%). The main associations were: cefotaxime + Gentamycin + Metronidazole (35.2%), Amikacin Imipenem + + Metronidazole (12.7%), Imipenem + amikacin (9.8%), Piperacillin / Tazobactam + amikacin (9.8%) + amikacin and ertapenem (5.88%). Probabilitic antibiotic therapy was

  5. Emergence of Serratia marcescens isolates possessing carbapenem-hydrolysing β-lactamase KPC-2 from China.

    PubMed

    Lin, X; Hu, Q; Zhang, R; Hu, Y; Xu, X; Lv, H

    2016-09-01

    Eighty-three carbapenem-resistant Serratia marcescens isolates were recovered from Zhejiang Provincial People's Hospital, China. The minimum inhibitory concentrations of imipenem, meropenem, and ertapenem for all isolates were 2 to >128 μg/mL. Polymerase chain reaction indicated that 63 S. marcescens isolates produced Klebsiella pneumoniae carbapenemase (KPC)-2. Clone A (15 isolates) and clone B (41 isolates) were the two dominant clones and clone A strains were gradually replaced by clone B strains between 2011 and 2014. The results indicate that blaKPC-2-positive S. marcescens emerged in our hospital as the major mechanism of carbapenem resistance.

  6. [Antimicrobial susceptibility of probiotics].

    PubMed

    Xu, Jin; Liu, Xiumei; Yang, Baolan; Li, Zhigang

    2008-05-01

    The aim of our study was to analyse the antibiotic susceptibility of 31 probiotics strains, including 9 Bifidobacterium and 22 Lactobacillus used for the manufacture of various fermented foods in China. Probiotics are tested for minimum inhibitory concentrations (MIC) of 24 kinds of antibiotics by broth dilution method on cation-adjusted Mueller-Hinton broth with lysed horse blood. 31 strains of probiotics were sensitive to ampicillin, penicillin, imipenem, gentamicine, amoxicillin, amoxicillin/clavulanic acid, gatifloxacin, erythromycin, clindamycin, and resistant to nalidixic acid, vancomycine, fosfomycin.

  7. Characterization of a novel IMP-28 metallo-β-lactamase from a Spanish Klebsiella oxytoca clinical isolate.

    PubMed

    Pérez-Llarena, Francisco José; Fernández, Ana; Zamorano, Laura; Kerff, Frédéric; Beceiro, Alejandro; Aracil, Belén; Cercenado, Emilia; Miro, Elisenda; Oliver, Antonio; Oteo, Jesús; Navarro, Ferran; Bou, Germán

    2012-08-01

    An isolate of Klebsiella oxytoca carrying a novel IMP metallo-β-lactamase was discovered in Madrid, Spain. The bla(IMP-28) gene is part of a chromosomally located class I integron. The IMP-28 k(cat)/K(m) values for ampicillin, ceftazidime, and cefepime and, to a lesser extent, imipenem and meropenem, are clearly lower than those of IMP-1. The His306Gln mutation may induce important modifications of the L3 loop and thus of substrate accessibility and hydrolysis and be the main reason for this behavior.

  8. Severe pneumonia due to Nocardia otitidiscaviarum identified by mass spectroscopy in a cotton farmer

    PubMed Central

    Liu, Chen; Feng, Mei; Zhu, Jing; Tao, Ye; Kang, Mei; Chen, Lei

    2017-01-01

    Abstract Rationale: Nocardia species are aerobic saprophytic bacilli. Among Nocardia species, Nocardia otitidiscaviarum (N otitidiscaviarum) is rarely reported in pulmonary infection. Patient concerns: We reported a case of N otitidiscaviarum pneumonia in a cotton farmer. Diagnoses: N otitidiscaviarum pneumonia was identified by mass spectroscopy. Interventions: Combined treatments (amikacin, imipenem and trimethoprim-sulfamethoxazole) were administered after identification of N otitidiscaviarum. Outcomes: The patient eventually died from severe respiratory insufficiency in the hospital. Lessons: Early precise diagnosis and prompt combined therapy are of vital importance in severe Nocardia pulmonary infection. PMID:28353613

  9. Alterations of OprD in Carbapenem-Intermediate and -Susceptible Strains of Pseudomonas aeruginosa Isolated from Patients with Bacteremia in a Spanish Multicenter Study

    PubMed Central

    Cabot, Gabriel; Rodríguez, Cristina; Roman, Elena; Tubau, Fe; Macia, María D.; Moya, Bartolomé; Zamorano, Laura; Suárez, Cristina; Peña, Carmen; Domínguez, María A.; Moncalián, Gabriel; Oliver, Antonio; Martínez-Martínez, Luis

    2012-01-01

    We investigated the presence of OprD mutations in 60 strains of metallo-ß-lactamase-negative Pseudomonas aeruginosa intermediately susceptible (IS [n = 12]; MIC = 8 μg/ml) or susceptible (S [n = 48]; MICs ≤ 1 to 4 μg/ml) to imipenem and/or meropenem that were isolated from patients with bacteremia in order to evaluate their impact on carbapenem susceptibility profiles. The presence of mutations in oprD was detected by sequencing analysis. OprD expression was assessed by both outer membrane protein (OMP) analysis and real-time PCR (RT-PCR). Fourteen (23%) isolates had an OprD identical to that of PAO1, and OprD modifications were detected in 46 isolates (77%). Isolates were classified as OprD “full-length types” (T1 [n = 40, including both wild-type OprD and variants showing several polymorphisms]) and OprD “deficient types” (T2 [n = 3 for OprD frameshift mutations] and T3 [n = 17 for premature stop codons in oprD]). RT-PCR showed that 5 OprD type T1 isolates presented reduced transcription of oprD (0.1- to 0.4-fold compared to PAO1), while oprD levels increased more than 2-fold over that seen with PAO1 in 4 OprD type T1 isolates. A total of 50% of the isolates belonging to OprD “deficient types” were susceptible to both carbapenems, and 40% were susceptible to meropenem and intermediately susceptible to imipenem. Only one isolate (5%) within this group was intermediately susceptible to both carbapenems, and one (5%) was susceptible to imipenem and intermediately susceptible to meropenem. We concluded that OprD inactivating mutations in clinical isolates of P. aeruginosa are not restricted only to carbapenem-resistant isolates but are also found in isolates with imipenem or meropenem MICs of only 0.06 to 4 μg/ml. PMID:22290967

  10. AmpG Inactivation Restores Susceptibility of Pan-β-Lactam-Resistant Pseudomonas aeruginosa Clinical Strains▿

    PubMed Central

    Zamorano, Laura; Reeve, Thomas M.; Juan, Carlos; Moyá, Bartolomé; Cabot, Gabriel; Vocadlo, David J.; Mark, Brian L.; Oliver, Antonio

    2011-01-01

    Constitutive AmpC hyperproduction is the most frequent mechanism of resistance to the weak AmpC inducers antipseudomonal penicillins and cephalosporins. Previously, we demonstrated that inhibition of the β-N-acetylglucosaminidase NagZ prevents and reverts this mechanism of resistance, which is caused by ampD and/or dacB (PBP4) mutations in Pseudomonas aeruginosa. In this work, we compared NagZ with a second candidate target, the AmpG permease for GlcNAc-1,6-anhydromuropeptides, for their ability to block AmpC expression pathways. Inactivation of nagZ or ampG fully restored the susceptibility and basal ampC expression of ampD or dacB laboratory mutants and impaired the emergence of one-step ceftazidime-resistant mutants in population analysis experiments. Nevertheless, only ampG inactivation fully blocked ampC induction, reducing the MICs of the potent AmpC inducer imipenem from 2 to 0.38 μg/ml. Moreover, through population analysis and characterization of laboratory mutants, we showed that ampG inactivation minimized the impact on resistance of the carbapenem porin OprD, reducing the MIC of imipenem for a PAO1 OprD mutant from >32 to 0.5 μg/ml. AmpG and NagZ targets were additionally evaluated in three clinical isolates that are pan-β-lactam resistant due to AmpC hyperproduction, OprD inactivation, and overexpression of several efflux pumps. A marked increase in susceptibility to ceftazidime and piperacillin-tazobactam was observed in both cases, while only ampG inactivation fully restored wild-type imipenem susceptibility. Susceptibility to meropenem, cefepime, and aztreonam was also enhanced, although to a lower extent due to the high impact of efflux pumps on the activity of these antibiotics. Thus, our results suggest that development of small-molecule inhibitors of AmpG could provide an excellent strategy to overcome the relevant mechanisms of resistance (OprD inactivation plus AmpC induction) to imipenem, the only currently available β-lactam not

  11. Multicenter evaluation of antimicrobial resistance to six broad-spectrum beta-lactams in Colombia using the Etest method. The Colombian Antimicrobial Resistance Study Group.

    PubMed

    Jones, R N; Salazar, J C; Pfaller, M A; Doern, G V

    1997-12-01

    The need for comprehensive and quantitative accurate antimicrobial resistance surveillance systems has become acute as a guide to problem recognition and to focus local interventions. A multilaboratory (10 medical centers) Colombia surveillance project was initiated in early 1997 to monitor the potency and spectrum of six (cefepime, cefotaxime, ceftazidime, cefoperazone/sulbactam, aztreonam, and imipenem) broad-spectrum antimicrobial agents tested against 100 organisms per participant center (802 strains). Ten groups of organisms were tested by a reference-quality method (Etest; AB BIODISK, Solna, Sweden) with results validated by concurrent quality control and additional challenge strain analysis. Results from nine qualifying medical centers were tabulated, and 95.7 to 96.8% of quality assurance tests were within expected ranges. Only cefepime (90.1-100.0% susceptible) and imipenem (96.3-100.0%) were active against all Enterobacteriaceae at > 90% of susceptible isolates using the breakpoint concentrations recommended by the National Committee for Clinical Laboratory Standards. Among ceftazidime- (or cefotaxime- or aztreonam-) resistant Enterobacter spp. and Citrobacter freundii, cefepime remained active, but not cefoperazone with sulbactam. Escherichia coli and Klebsiella spp. strains having resistance phenotypes consistent with extended spectrum beta-lactamase production were discovered in approximately 5 to 10% of isolates. All tested drugs except ceftazidime (31.8-57.7% susceptible) were active against > 94% of oxacillin-susceptible staphylococci. Similar rates of resistance (9.1-14.8%) were observed in Pseudomonas aeruginosa for five of six drugs (not cefotaxime; 15.9% of strains were susceptible). Acinetobacter spp. isolates were most susceptible to imipenem (95.8%), cefepime (86.1%), and cefoperazone/sulbactam (83.3%). Overall for the 1997 order of antimicrobial spectrums for these tested compounds was: imipenem (96.6%) > cefepime (93.6%) > cefoperazone

  12. First occurrence of blaOXA-58 in Acinetobacter baumannii isolated from a clinical sample in Southern Brazil

    PubMed Central

    de Souza Gusatti, Carolina; Bertholdo, Lauren Martins; Otton, Letícia Muner; Marchetti, Desirée Padilha; Ferreira, Alessandra Einsfeld; Corção, Gertrudes

    2012-01-01

    This is the first report of an Acinetobacter baumannii from clinical origin carrying the blaOXA-58 gene in Brazil. The isolate included in this study was from a patient during an outbreak in Porto Alegre, RS, Southern Brazil, in 2007. It was resistant to most of the beta-lactams tested, it has also the blaOXA-65 gene and the ISAbal sequence located upstream to both blaOXA genes detected and it has a MIC of imipenem of 64 μg/mL. PMID:24031824

  13. Comparison of different methods for determining beta-lactam susceptibility in Pseudomonas aeruginosa.

    PubMed

    Sapino, Barbara; Mazzuccato, Sandra; Solinas, Maria; Gion, Massimo; Grandesso, Stefano

    2012-10-01

    This study compared the results of antimicrobial susceptibility testing of 77 clinical strains isolated for Pseudomonas aeruginosa to five beta-lactam agents: aztreonam, ceftazidime, imipenem, meropenem and piperacillin+tazobactam. Four different methods were employed: two automated systems (VITEK 2 and Sensititre) and two standardized manual methods (Kirby-Bauer and E-test). The concordances for the susceptibility categories were better for Kirby-Bauer (medium value =89.6%), followed by Sensititre (medium value =87.0%) and VITEK 2 (medium value =82.8%). The disk diffusion method did not present very major errors in comparison to the two automated systems.

  14. Inhibition of LpxC Increases Antibiotic Susceptibility in Acinetobacter baumannii

    PubMed Central

    García-Quintanilla, Meritxell; Caro-Vega, José M.; Pulido, Marina R.; Moreno-Martínez, Patricia; Pachón, Jerónimo

    2016-01-01

    LpxC inhibitors have generally shown poor in vitro activity against Acinetobacter baumannii. We show that the LpxC inhibitor PF-5081090 inhibits lipid A biosynthesis, as determined by silver staining and measurements of endotoxin levels, and significantly increases cell permeability. The presence of PF-5081090 at 32 mg/liter increased susceptibility to rifampin, vancomycin, azithromycin, imipenem, and amikacin but had no effect on susceptibility to ciprofloxacin and tigecycline. Potentiating existing antibiotics with LpxC inhibitors may represent an alternative treatment strategy for multidrug-resistant A. baumannii. PMID:27270288

  15. Resistance Pattern of Pseudomonas aeruginosa in a Tertiary Care Hospital of Kanchipuram, Tamilnadu, India

    PubMed Central

    Reddy A., Suneel Kumar; S., Sivasankari; C., Anitha; V., Somasunder; MS., Kumudhavathi; SK., Amshavathani; V., Venugopal

    2014-01-01

    Purpose: This study was undertaken to analyze the extended spectrum of β lactamase (ESBL), metallo β lactamase (MBL) & AmpC production in Pseudomonas aeruginosa in various clinical samples. Materials & Methods: One hundred four non repetitive clinical specimens were inoculated onto nutrient agar, blood agar and incubated at 37oC overnight. The colonies were tested for oxidase test and other biochemical tests and antibiogram. ESBL screening was done using 3rd generation cephalosporins and confirmatory combined double disc test, imipenem-EDTA double disc synergy test for MBL enzyme and AmpC test using Cefoxitin disc. Results & Analysis: Out of 104 P.aeruginosa isolates, 42.30% were ESBL producer, 15.38 % MBL producer and none were AmpC producer. Imipenem, Ofloxacin, and aminoglycosides (amikacin (29.8%) tobramycin (29.8%) and netilmycin (13.46%) has got the better antipseudomonal activity in this study. 43 (41.35%) P.aeruginosa was found to be Multi Drug Resistant (MDR). Conclusion: This study highlights the prevalence of ESBL, MBL and MDR P.aeruginosa. Carbapenems and aminoglycosides are promising drugs with antipseudomonal activity in our study. PMID:24995180

  16. Characterization of a Nosocomial Outbreak Caused by a Multiresistant Acinetobacter baumannii Strain with a Carbapenem-Hydrolyzing Enzyme: High-Level Carbapenem Resistance in A. baumannii Is Not Due Solely to the Presence of β-Lactamases

    PubMed Central

    Bou, Germán; Cerveró, Gonzalo; Domínguez, M. Angeles; Quereda, Carmen; Martínez-Beltrán, Jesús

    2000-01-01

    From February to November 1997, 29 inpatients at Ramón y Cajal Hospital, Madrid, Spain, were determined to be either colonized or infected with imipenem- and meropenem-resistant Acinetobacter baumannii (IMRAB) strains (MICs, 128 to 256 μg/ml). A wide antibiotic multiresistance profile was observed with IMRAB strains. For typing IMRAB isolates, pulsed-field gel electrophoresis was used. For comparative purposes, 30 imipenem- and meropenem-susceptible A. baumannii (IMSAB) strains isolated before, during, and after the outbreak were included in this study. The molecular-typing results showed that the outbreak was caused by a single IMRAB strain (genotype A). By cloning experiments we identified a class D β-lactamase (OXA-24) encoded in the chromosomal DNA of this IMRAB strain which showed carbapenem hydrolysis. Moreover, the outer membrane profile of the IMRAB strain showed a reduction in the expression of two porins at 22 and 33 kDa when compared with genetically related IMSAB isolates. In addition no efflux mechanisms were identified in the IMRAB strains. In summary, we report here the molecular characterization of a nosocomial outbreak caused by one multiresistant A. baumannii epidemic strain that harbors a carbapenem-hydrolyzing enzyme. Although alterations in the penicillin-binding proteins cannot be ruled out, the reduction in the expression of two porins and the presence of this OXA-derived β-lactamase are involved in the carbapenem resistance of the epidemic nosocomial IMRAB strain. PMID:10970374

  17. Most Enterobacter aerogenes strains in France belong to a prevalent clone.

    PubMed

    Bosi, C; Davin-Regli, A; Bornet, C; Mallea, M; Pages, J M; Bollet, C

    1999-07-01

    The aim of this study was to determine the distribution in France of the Enterobacter aerogenes prevalent clone isolated in the hospitals of the Marseille area (A. Davin-Regli, D. Monnet, P. Saux, C. Bosi, R. Charrel, A. Barthelemy, and C. Bollet, J. Clin. Microbiol. 34:1474-1480, 1996). A total of 123 E. aerogenes isolates were collected from 23 hospital laboratories and analyzed by random amplification of polymorphic DNA and enterobacterial repetitive intergenic consensus-PCR to determine their epidemiological relatedness. Molecular typing revealed that 21 of the 23 laboratories had isolated this prevalent clone harboring the plasmid encoding for extended-spectrum beta-lactamase of the TEM-24 type. Most isolates were susceptible only to imipenem and gentamicin. Their dissemination seems to be clonal and was probably the result of the general use of broad-spectrum cephalosporins and quinolones. Four isolates showed an alteration of their outer membrane proteins, causing decrease of susceptibility to third-generation cephalosporins and imipenem and leading to the critical situation of having no alternative therapeutic. The large dissemination of the E. aerogenes prevalent clone probably results from its good adaptation to the antibiotics administered in France and the hospital environment, particularly in intensive care units.

  18. Multiresistance and endemic status of acinetobacter baumannii associated with nosocomial infections in a tunisian hospital: a critical situation in the intensive care units

    PubMed Central

    Ben Othman, A.; Zribi, M.; Masmoudi, A.; Abdellatif, S.; Ben Lakhal, S.; Fendri, C.

    2011-01-01

    Acinetobacter baumannii is often implicated in hospital outbreaks in Tunisia. It’s a significant opportunistic pathogen associated with serious underlying diseases such as pneumoniae, meningitis and urinary tract infections. The aim of our study was to evaluate its degree of endemicity and its antibiotic resistance evolution essentially in the unit care where its isolation was predominant (57%). This study used 3 methods: antibiotyping, RAPD using 2 primers VIL 1, VIL5 and PFGE with ApaI restriction enzyme. The presence of integron1 and 2 was also studied. Antibiotyping showed that 92% of patients were resistant of all ß- lactams (except Imipenem) and that the resistance to Imipenem occurred in 47% of cases. RAPD profiles obtained with the 2 arbitrarily primers VIL1 and VIL5 gave respectively 5 and 4groups and PFGE fingerprinting patterns revealed 22 different pulsotypes. Integron 1 was present in 25% of unrelated strains and type 2 integron was not detected in any of the studied strains. Among 204 strains, multiple and heterogeneous groups were detected with the genomic studies. In addition, any correlation was obtained with the antibiotyping results. These findings demonstrate the endemic status of A. baumannii in our hospital and the persistence of a large number of multiresistant strains in the unit’s care. When outbreaks of A. baumannii occur, it’s essential to develop restricted hygiene procedures and a serious surveillance of critical units such as ICU for very ill patients. PMID:24031648

  19. Effect of various antibiotics on modulation of intestinal microbiota and bile acid profile in mice.

    PubMed

    Zhang, Youcai; Limaye, Pallavi B; Renaud, Helen J; Klaassen, Curtis D

    2014-06-01

    Antibiotic treatments have been used to modulate intestinal bacteria and investigate the role of intestinal bacteria on bile acid (BA) homeostasis. However, knowledge on which intestinal bacteria and bile acids are modified by antibiotics is limited. In the present study, mice were administered various antibiotics, 47 of the most abundant bacterial species in intestine, as well as individual BAs in plasma, liver, and intestine were quantified. Compared to the two antibiotic combinations (vancomycin+imipenem and cephalothin+neomycin), the three single antibiotics (metronidazole, ciprofloxacin and aztreonam) have less effect on intestinal bacterial profiles, and thus on host BA profiles and mRNA expression of genes that are important for BA homeostasis. The two antibiotic combinations decreased the ratio of Firmicutes to Bacteroidetes in intestine, as well as most secondary BAs in serum, liver and intestine. Additionally, the two antibiotic combinations significantly increased mRNA of the hepatic BA uptake transporters (Ntcp and Oatp1b2) and canalicular BA efflux transporters (Bsep and Mrp2), but decreased mRNA of the hepatic BA synthetic enzyme Cyp8b1, suggesting an elevated enterohepatic circulation of BAs. Interestingly, the two antibiotic combinations tended to have opposite effect on the mRNAs of most intestinal genes, which tended to be inhibited by vancomycin+imipenem but stimulated by cephalothin+neomycin. To conclude, the present study clearly shows that various antibiotics have distinct effects on modulating intestinal bacteria and host BA metabolism.

  20. Antimicrobial susceptibility of Escherichia coli isolated from shrimp (Litopenaeus vannamei) and pond environment in northeastern Brazil.

    PubMed

    Vieira, Regine H S Dos F; Carvalho, Edirsana M R; Carvalho, Fatima C T; Silva, Camila M; Sousa, Oscarina V; Rodrigues, Dalia P

    2010-04-01

    This study aimed to test the susceptibility of Escherichia coli strains isolated from the water, bottom sediments and individuals cultivated in shrimp farm ponds, to antibiotics belonging to different families, namely B-Lactams: Imipenem (IPM; 10 micro g), Ampicillin (AMP; 10 micro g), Cephalothin (CEP; 30 micro g), Cefoxitin (FOX; 30 micro g), Ceftriaxone (CRO; 30 micro g); Tetracycline: Tetracycline (TCY; 30 micro g); Aminoglycosides: Gentamicin (GEN; 10 micro g), Amikacin (AMK; 30 micro g); Chloramphenicol: Chloramphenicol (CHO; 30 micro g); Fluoroquinolones: Ciprofloxacin (CIP; 5 micro g); Nitrofurans: Nitrofurantoin (NIT; 300 micro g); Sulfonamides: Trimethoprim-Sulfamethoxazole (SXT; 30 micro g); Quilononas: Nalidixic Acid (NAL; 30 micro g). In the laboratory, the method of dissemination (Test Kirby-Bauer) was performed in order to fulfill the antibiogram tests. The results showed high indices of resistance to Imipenem, Cephalothin and Ampicillin. Chloramphenicol, Nitrofurantoin, Cefoxitin, Ceftiaxone and Ciprofloxacin have displayed the highest index of sensitive strains. The antibiotic resistance index (ARI) and the multiple resistance index (MAR) varied within the ranges of 0.068-0.077 and 0.15-0.39, respectively. More than 90.5% of strains of Escherichia coli showed a variety of resistance profiles to the tested antibiotics. The high indices of resistance may be a consequence of indiscriminate use of antibiotics, but also the transfer of resistance through mobile genetic elements found in shrimp farms.

  1. Early detection of metallo-β-lactamase NDM-1- and OXA-23 carbapenemase-producing Acinetobacter baumannii in Libyan hospitals.

    PubMed

    Mathlouthi, Najla; El Salabi, Allaaeddin Ali; Ben Jomàa-Jemili, Mariem; Bakour, Sofiane; Al-Bayssari, Charbel; Zorgani, Abdulaziz A; Kraiema, Abdulmajeed; Elahmer, Omar; Okdah, Liliane; Rolain, Jean-Marc; Chouchani, Chedly

    2016-07-01

    Acinetobacter baumannii is an opportunistic pathogen causing various nosocomial infections. The aim of this study was to characterise the molecular support of carbapenem-resistant A. baumannii clinical isolates recovered from two Libyan hospitals. Bacterial isolates were identified by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF/MS). Antibiotic susceptibility testing was performed using disk diffusion and Etest methods, and carbapenem resistance determinants were studied by PCR amplification and sequencing. Multilocus sequence typing (MLST) was performed for typing of the isolates. All 36 imipenem-resistant isolates tested were identified as A. baumannii. The blaOXA-23 gene was detected in 29 strains (80.6%). The metallo-β-lactamase blaNDM-1 gene was detected in eight isolates (22.2%), showing dissemination of multidrug-resistant (MDR) A. baumannii in Tripoli Medical Center and Burn and Plastic Surgery Hospital in Libya, including one isolate that co-expressed the blaOXA-23 gene. MLST revealed several sequence types (STs). Imipenem-resistant A. baumannii ST2 was the predominant clone (16/36; 44.4%). This study shows that NDM-1 and OXA-23 contribute to antibiotic resistance in Libyan hospitals and represents the first incidence of the association of these two carbapenemases in an autochthonous MDR A. baumannii isolated from patients in Libya, indicating that there is a longstanding infection control problem in these hospitals.

  2. Genetic Lineages and Antimicrobial Resistance in Pseudomonas spp. Isolates Recovered from Food Samples.

    PubMed

    Estepa, Vanesa; Rojo-Bezares, Beatriz; Torres, Carmen; Sáenz, Yolanda

    2015-06-01

    Raw food is a reservoir of Pseudomonas isolates that could be disseminated to consumers. The presence of Pseudomonas spp. was studied in food samples, and the phenotypic and genotypic characterizations of the recovered isolates were analyzed. Two samples of meat (3%, turkey and beef) and 13 of vegetables (22%, 7 green peppers and 6 tomatoes) contained Pseudomonas spp. A total of 20 isolates were identified, and were classified as follows (number of isolates): P. aeruginosa (5), P. putida (5), P. nitroreducens (4), P. fulva (2), P. mosselli (1), P. mendocina (1), P. monteilii (1), and Pseudomonas sp. (1). These 20 Pseudomonas isolates were clonally different by pulsed-field-gel-electrophoresis, and were resistant to the following antibiotics: ticarcillin (85%), aztreonam (30%), cefepime (10%), imipenem (10%), and meropenem (5%), but were susceptible to ceftazidime, piperacillin, piperacillin-tazobactam, doripenem, gentamicin, tobramycin, amikacin, ciprofloxacin, norfloxacin, and colistin. Only one strain (Ps158) presented a class 1 integron lacking the 3' conserved segment. The five P. aeruginosa strains were typed by multilocus sequence typing in five different sequence-types (ST17, ST270, ST800, ST1455, and ST1456), and different mutations were detected in protein OprD that were classified in three groups. One strain (Ps159) showed a new insertion sequence (ISPa47) truncating the oprD gene, and conferring resistance to imipenem.

  3. Antibiotic resistance and extended-spectrum β-lactamases in isolated bacteria from seawater of Algiers beaches (Algeria).

    PubMed

    Alouache, Souhila; Kada, Mohamed; Messai, Yamina; Estepa, Vanesa; Torres, Carmen; Bakour, Rabah

    2012-01-01

    The aim of the study was to evaluate bacterial antibiotic resistance in seawater from four beaches in Algiers. The most significant resistance rates were observed for amoxicillin and ticarcillin, whereas they were relatively low for ceftazidime, cefotaxime and imipenem. According to sampling sites, the highest resistance rates were recorded for 2 sites subjected to chemical and microbiological inputs (amoxicillin, 43% and 52%; ticarcillin, 19.6% and 47.7%), and for 2 sites relatively preserved from anthropogenic influence, resistance rates were lowest (amoxicillin, 1.5% and 16%; ticarcillin, 0.8% and 2.6%). Thirty-four bacteria resistant to imipenem (n=14) or cefotaxime (n=20) were identified as Pseudomonas aeruginosa (n=15), Pseudomonas fluorescens (7), Stenotrophomonas maltophilia (4), Burkholderia cepacia (2), Bordetella sp. (1), Pantoea sp. (1), Acinetobacter baumannii (1), Chryseomonas luteola (1), Ochrobactrum anthropi (1) and Escherichia coli (1). Screening for extended spectrum β-lactamase showed the presence of CTX-M-15 β-lactamase in the E. coli isolate, and the encoding gene was transferable in association with the IncI1 plasmid of about 50 kbp. Insertion sequence ISEcp1B was located upstream of the CTX-M-15 gene. This work showed a significant level of resistance to antibiotics, mainly among environmental saprophytic bacteria. Transmissible CTX-M-15 was detected in E. coli; this may mean that contamination of the environment by resistant bacteria may cause the spread of resistance genes.

  4. Antibiotic Resistance and Extended-Spectrum β-Lactamases in Isolated Bacteria from Seawater of Algiers Beaches (Algeria)

    PubMed Central

    Alouache, Souhila; Kada, Mohamed; Messai, Yamina; Estepa, Vanesa; Torres, Carmen; Bakour, Rabah

    2012-01-01

    The aim of the study was to evaluate bacterial antibiotic resistance in seawater from four beaches in Algiers. The most significant resistance rates were observed for amoxicillin and ticarcillin, whereas they were relatively low for ceftazidime, cefotaxime and imipenem. According to sampling sites, the highest resistance rates were recorded for 2 sites subjected to chemical and microbiological inputs (amoxicillin, 43% and 52%; ticarcillin, 19.6% and 47.7%), and for 2 sites relatively preserved from anthropogenic influence, resistance rates were lowest (amoxicillin, 1.5% and 16%; ticarcillin, 0.8% and 2.6%). Thirty-four bacteria resistant to imipenem (n=14) or cefotaxime (n=20) were identified as Pseudomonas aeruginosa (n=15), Pseudomonas fluorescens(7), Stenotrophomonas maltophilia(4), Burkholderia cepacia(2), Bordetella sp. (1), Pantoea sp. (1), Acinetobacter baumannii(1), Chryseomonas luteola(1), Ochrobactrum anthropi(1) and Escherichia coli(1). Screening for extended spectrum β-lactamase showed the presence of CTX-M-15 β-lactamase in the E. coli isolate, and the encoding gene was transferable in association with the IncI1 plasmid of about 50 kbp. Insertion sequence ISEcp1B was located upstream of the CTX-M-15 gene. This work showed a significant level of resistance to antibiotics, mainly among environmental saprophytic bacteria. Transmissible CTX-M-15 was detected in E. coli; this may mean that contamination of the environment by resistant bacteria may cause the spread of resistance genes. PMID:22095134

  5. The Role of the β5-α11 Loop in the Active-Site Dynamics of Acylated Penicillin-Binding Protein A from Mycobacterium tuberculosis

    SciTech Connect

    Fedarovich, Alena; Nicholas, Robert A.; Davies, Christopher

    2013-04-22

    Penicillin-binding protein A (PBPA) is a class B penicillin-binding protein that is important for cell division in Mycobacterium tuberculosis. We have determined a second crystal structure of PBPA in apo form and compared it with an earlier structure of apoenzyme. Significant structural differences in the active site region are apparent, including increased ordering of a β-hairpin loop and a shift of the SxN active site motif such that it now occupies a position that appears catalytically competent. Using two assays, including one that uses the intrinsic fluorescence of a tryptophan residue, we have also measured the second-order acylation rate constants for the antibiotics imipenem, penicillin G, and ceftriaxone. Of these, imipenem, which has demonstrable anti-tubercular activity, shows the highest acylation efficiency. Crystal structures of PBPA in complex with the same antibiotics were also determined, and all show conformational differences in the β5–α11 loop near the active site, but these differ for each β-lactam and also for each of the two molecules in the crystallographic asymmetric unit. Overall, these data reveal the β5–α11 loop of PBPA as a flexible region that appears important for acylation and provide further evidence that penicillin-binding proteins in apo form can occupy different conformational states.

  6. Evaluation of polymorphisms in pbp4 gene and genetic diversity in penicillin-resistant, ampicillin-susceptible Enterococcus faecalis from hospitals in different states in Brazil.

    PubMed

    Infante, Victor Hugo Pacagnelli; Conceição, Natália; de Oliveira, Adriana Gonçalves; Darini, Ana Lúcia da Costa

    2016-04-01

    The aim of the present study was to verify whether penicillin-resistant, ampicillin-susceptible Enterococcus faecalis (PRASEF) occurred in Brazil prior to the beginning of the 21st century, and to verify whether ampicillin susceptibility can predict susceptibility to other β-lactams in E. faecalis with this inconsistent phenotype. The presence of polymorphisms in the pbp4 gene and genetic diversity among the isolates were investigated. Of 21 PRASEF analyzed, 5 (23.8%) and 4 (19.0%) were imipenem and piperacillin resistant simultaneously by disk diffusion and broth dilution respectively, contradicting the current internationally accepted standards of susceptibility testing. Sequencing of pbp4 gene revealed an amino acid substitution (Asp-573→Glu) in all PRASEF isolates but not in the penicillin-susceptible, ampicillin-susceptible E. faecalis. Most PRASEF (90.5%) had related pulsed-field gel electrophoresis profiles, but were different from other PRASEF described to date. Results demonstrate that penicillin-resistant, ampicillin-susceptible phenotype was already a reality in the 1990s in E. faecalis isolates in different Brazilian states, and some of these isolates were also imipenem- and piperacillin-resistant; therefore, internationally accepted susceptibility criteria cannot be applied to these isolates. According to pbp4 gene sequencing, this study suggests that a specific amino acid substitution in pbp4 gene found in all PRASEF analyzed is associated with penicillin resistance.

  7. Efficacy of Single and Combined Antibiotic Treatments of Anthrax in Rabbits

    PubMed Central

    Weiss, Shay; Altboum, Zeev; Glinert, Itai; Schlomovitz, Josef; Sittner, Assa; Bar-David, Elad; Kobiler, David

    2015-01-01

    Respiratory anthrax is a fatal disease in the absence of early treatment with antibiotics. Rabbits are highly susceptible to infection with Bacillus anthracis spores by intranasal instillation, succumbing within 2 to 4 days postinfection. This study aims to test the efficiency of antibiotic therapy to treat systemic anthrax in this relevant animal model. Delaying the initiation of antibiotic administration to more than 24 h postinfection resulted in animals with systemic anthrax in various degrees of bacteremia and toxemia. As the onset of symptoms in humans was reported to start on days 1 to 7 postexposure, delaying the initiation of treatment by 24 to 48 h (time frame for mass distribution of antibiotics) may result in sick populations. We evaluated the efficacy of antibiotic administration as a function of bacteremia levels at the time of treatment initiation. Here we compare the efficacy of treatment with clarithromycin, amoxicillin-clavulanic acid (Augmentin), imipenem, vancomycin, rifampin, and linezolid to the previously reported efficacy of doxycycline and ciprofloxacin. We demonstrate that treatment with amoxicillin-clavulanic acid, imipenem, vancomycin, and linezolid were as effective as doxycycline and ciprofloxacin, curing rabbits exhibiting bacteremia levels of up to 105 CFU/ml. Clarithromycin and rifampin were shown to be effective only as a postexposure prophylactic treatment but failed to treat the systemic (bacteremic) phase of anthrax. Furthermore, we evaluate the contribution of combined treatment of clindamycin and ciprofloxacin, which demonstrated improvement in efficacy compared to ciprofloxacin alone. PMID:26392505

  8. Characterization of extended-spectrum beta-lactamases and antimicrobial resistance of Klebsiella pneumoniae in intra-abdominal infection isolates in Latin America, 2008-2012. Results of the Study for Monitoring Antimicrobial Resistance Trends.

    PubMed

    Kazmierczak, Krystyna M; Lob, Sibylle H; Hoban, Daryl J; Hackel, Meredith A; Badal, Robert E; Bouchillon, Samuel K

    2015-07-01

    The Study for Monitoring Antimicrobial Resistance Trends has monitored the in vitro activity of several recommended antimicrobials used in the management of intra-abdominal infections (IAIs) globally since 2002. In this report, we document the changing susceptibility patterns to recommended antimicrobials in Klebsiella pneumoniae isolates from patients with IAIs in 11 Latin American countries between 2008 and 2012 and describe the beta-lactamases encoded by phenotypically extended-spectrum beta-lactamase (ESBL)-positive and ertapenem-nonsusceptible isolates. Overall, the incidence of phenotypically ESBL-positive K. pneumoniae did not change significantly from 2008 (40.4%) to 2012 (41.2%) (P > 0.05). However, trend analysis documented an increase in isolates encoding K. pneumoniae carbapenemase (KPC) or both KPC and an ESBL. Decreasing susceptibility (P < 0.05) was noted for cefepime, ceftazidime, ceftriaxone, ertapenem, and imipenem among all K. pneumoniae, as well as for cefepime, cefotaxime, cefoxitin, ceftriaxone, ertapenem, and imipenem among ESBL-positive isolates, while susceptibility of ESBL-negative isolates to ampicillin-sulbactam actually increased (P < 0.05).

  9. Differences in Rhodococcus equi Infections Based on Immune Status and Antibiotic Susceptibility of Clinical Isolates in a Case Series of 12 Patients and Cases in the Literature

    PubMed Central

    Suzuki, Yasuhiro; Ribes, Julie A.; Thornton, Alice

    2016-01-01

    Rhodococcus equi is an unusual zoonotic pathogen that can cause life-threatening diseases in susceptible hosts. Twelve patients with R. equi infection in Kentucky were compared to 137 cases reported in the literature. Although lungs were the primary sites of infection in immunocompromised patients, extrapulmonary involvement only was more common in immunocompetent patients (P < 0.0001). Mortality in R. equi-infected HIV patients was lower in the HAART era (8%) than in pre-HAART era (56%) (P < 0.0001), suggesting that HAART improves prognosis in these patients. Most (85–100%) of clinical isolates were susceptible to vancomycin, clarithromycin, rifampin, aminoglycosides, ciprofloxacin, and imipenem. Interestingly, there was a marked difference in susceptibility of the isolates to cotrimoxazole between Europe (35/76) and the US (15/15) (P < 0.0001). Empiric treatment of R. equi infection should include a combination of two antibiotics, preferably selected from vancomycin, imipenem, clarithromycin/azithromycin, ciprofloxacin, rifampin, or cotrimoxazole. Local antibiograms should be checked prior to using cotrimoxazole due to developing resistance. PMID:27631004

  10. Prevalence and Antibiotic Susceptibility Patterns of Extended-Spectrum ß-Lactamase and Metallo-ß-Lactamase-Producing Uropathogenic Escherichia coli Isolates.

    PubMed

    Ghadiri, Hamed; Vaez, Hamid; Razavi-Azarkhiavi, Kamal; Rezaee, Ramin; Haji-Noormohammadi, Mehdi; Rahimi, Ali Asghar; Vaez, Vahid; Kalantar, Enayatollah

    2014-01-01

    Healthcare professionals worldwide have expressed concern over infections by extended-spectrum ß-lactamase (ESBL) and metallo-ß-lactamase (MBL)-producing bacteria. We evaluated the prevalence of ESBL- and MBL-producing Escherichia coli (E. coli) isolated from community-acquired urinary tract infections (UTIs) and their antibiotic-resistance profiles at 3 private laboratories in Tehran, Iran. E. coli isolates were mostly susceptible to meropenem (90.4%) and imipenem (90.0%), followed by amikacin (89.0%) and gentamicin (84.7%). Moreover, we detected that, of the E. coli isolates, 67 (22.3%) were ESBL producers and 21 (7.0%) of E. coli isolates were MBL positive via the imipenem-ethylenediaminetetraacetic acid (EDTA) combined disc test. This report is the first, to our knowledge, on the prevalence of MBL-producing uropathogenic E. coli (UPEC) strains in Iran. The antibiotic resistance of E. coli isolates revealed that 122 (40.7%) were multidrug resistant. The high number of antibiotic-resistant and ß-lactamase-producing UPEC strains necessitates further attention and consideration, particularly MBL-producing strains.

  11. Molecular characterization of acinetobacter isolates collected in intensive care units of six hospitals in Florence, Italy, during a 3-year surveillance program: a population structure analysis.

    PubMed

    Donnarumma, Francesca; Sergi, Simona; Indorato, Cristina; Mastromei, Giorgio; Monnanni, Roberto; Nicoletti, Pieluigi; Pecile, Patrizia; Cecconi, Daniela; Mannino, Roberta; Bencini, Sara; Fanci, Rosa; Bosi, Alberto; Casalone, Enrico

    2010-04-01

    The strain diversity and the population structure of nosocomial Acinetobacter isolated from patients admitted to different hospitals in Florence, Italy, during a 3-year surveillance program, were investigated by amplified fragment length polymorphism (AFLP). The majority of isolates (84.5%) were identified as A. baumannii, confirming this species as the most common hospital Acinetobacter. Three very distinct A. baumannii clonal groups (A1, A2, and A3) were defined. The A1 isolates appeared to be genetically related to the well-characterized European EU II clone. A2 was responsible for three outbreaks which occurred in two intensive care units. Space/time population dynamic analysis showed that A1 and A2 were successful nosocomial clones. Most of the A. baumannnii isolates were imipenem resistant. The genetic determinants of carbapenem resistance were investigated by multiplex PCR, showing that resistance, independently of hospital origin, period of isolation, or clonal group, was associated with the presence of a bla (OXA-58-like) gene and with ISAba2 and ISAba3 elements flanking this gene. bla (OXA-58) appeared to be horizontally transferred. This study showed that the high discriminatory power of AFLP is useful for identification and typing of nosocomial Acinetobacter isolates. Moreover the use of AFLP in a real-time surveillance program allowed us the recognition of clinically relevant and widespread clones and their monitoring in hospital settings. The correlation between clone diffusion, imipenem resistance, and the presence of the bla(OXA-58-like) gene is discussed.

  12. Short Synthetic β-Sheet Antimicrobial Peptides for the Treatment of Multidrug-Resistant Pseudomonas aeruginosa Burn Wound Infections.

    PubMed

    Zhong, Guansheng; Cheng, Junchi; Liang, Zhen Chang; Xu, Liang; Lou, Weiyang; Bao, Chang; Ong, Zhan Yuin; Dong, Huihui; Yang, Yi Yan; Fan, Weimin

    2017-04-01

    Pseudomonas aeruginosa is often implicated in burn wound infections; its inherent drug resistance often renders these infections extremely challenging to treat. This is further compounded by the problem of emerging drug resistance and the dearth of novel antimicrobial drug discovery in recent years. In the perennial search for effective antimicrobial compounds, the authors identify short synthetic β-sheet folding peptides, IRIKIRIK (IK8L), IRIkIrIK (IK8-2D), and irikirik (IK8D) as prime candidates owing to their high potency against Gram-negative bacteria. In this study, the peptides are first assayed against 20 clinically isolated multidrug-resistant P. aeruginosa strains in comparison with the conventional antibiotics imipenem and ceftazidime, and IK8L is demonstrated to be the most effective. IK8L also exhibits superior antibacterial killing kinetics compared to imipenem and ceftazidime. From transmission electron microscopy, confocal microscopy, and protein release analyses, IK8L shows membrane-lytic antimicrobial mechanism. Repeated use of IK8L does not induce drug resistance, while the bacteria develop resistance against the antibiotics after several times of treatment at sublethal doses. Analysis of mouse blood serum chemistry reveals that peptide does not induce systemic toxicity. The potential utility of IK8L in the in vivo treatment of P. aeruginosa-infected burn wounds is further demonstrated in a mouse model.

  13. Efficacy of Single and Combined Antibiotic Treatments of Anthrax in Rabbits.

    PubMed

    Weiss, Shay; Altboum, Zeev; Glinert, Itai; Schlomovitz, Josef; Sittner, Assa; Bar-David, Elad; Kobiler, David; Levy, Haim

    2015-12-01

    Respiratory anthrax is a fatal disease in the absence of early treatment with antibiotics. Rabbits are highly susceptible to infection with Bacillus anthracis spores by intranasal instillation, succumbing within 2 to 4 days postinfection. This study aims to test the efficiency of antibiotic therapy to treat systemic anthrax in this relevant animal model. Delaying the initiation of antibiotic administration to more than 24 h postinfection resulted in animals with systemic anthrax in various degrees of bacteremia and toxemia. As the onset of symptoms in humans was reported to start on days 1 to 7 postexposure, delaying the initiation of treatment by 24 to 48 h (time frame for mass distribution of antibiotics) may result in sick populations. We evaluated the efficacy of antibiotic administration as a function of bacteremia levels at the time of treatment initiation. Here we compare the efficacy of treatment with clarithromycin, amoxicillin-clavulanic acid (Augmentin), imipenem, vancomycin, rifampin, and linezolid to the previously reported efficacy of doxycycline and ciprofloxacin. We demonstrate that treatment with amoxicillin-clavulanic acid, imipenem, vancomycin, and linezolid were as effective as doxycycline and ciprofloxacin, curing rabbits exhibiting bacteremia levels of up to 10(5) CFU/ml. Clarithromycin and rifampin were shown to be effective only as a postexposure prophylactic treatment but failed to treat the systemic (bacteremic) phase of anthrax. Furthermore, we evaluate the contribution of combined treatment of clindamycin and ciprofloxacin, which demonstrated improvement in efficacy compared to ciprofloxacin alone.

  14. Crystallographic Studies of Two Bacterial AntibioticResistance Enzymes: Aminoglycoside Phosphotransferase (2')-Ic and GES-1\\beta-lactamase

    SciTech Connect

    Brynes, Laura; /Rensselaer Poly.

    2007-10-31

    Guiana Extended-Spectrum-1 (GES-1) and Aminoglycoside phosphotransferase (2')-Ic (APH(2')-Ic) are two bacteria-produced enzymes that essentially perform the same task: they provide resistance to an array of antibiotics. Both enzymes are part of a growing resistance problem in the medical world. In order to overcome the ever-growing arsenal of antibiotic-resistance enzymes, it is necessary to understand the molecular basis of their action. Accurate structures of these proteins have become an invaluable tool to do this. Using protein crystallography techniques and X-ray diffraction, the protein structure of GES-1 bound to imipenem (an inhibitor) has been solved. Also, APH(2')-Ic has been successfully crystallized, but its structure was unable to be solved using molecular replacement using APH(2')-Ib as a search model. The structure of GES-1, with bound imipenem was solved to a resolution of 1.89A, and though the inhibitor is bound with only moderate occupancy, the structure shows crucial interactions inside the active site that render the enzyme unable to complete the hydrolysis of the {beta}-lactam ring. The APH(2')-Ic dataset could not be matched to the model, APH(2')-Ib, with which it shares 25% sequence identity. The structural information gained from GES-1, and future studies using isomorphous replacement to solve the APH(2')-Ic structure can aid directly to the creation of novel drugs to combat both of these classes of resistance enzymes.

  15. Phytocompounds and modulatory effects of Anacardium microcarpum (cajui) on antibiotic drugs used in clinical infections

    PubMed Central

    Barbosa-Filho, Valter M; Waczuk, Emily P; Leite, Nadghia F; Menezes, Irwin RA; da Costa, José GM; Lacerda, Sírleis R; Adedara, Isaac A; Coutinho, Henrique Douglas Melo; Posser, Thais; Kamdem, Jean P

    2015-01-01

    Background The challenge of antibiotic resistance and the emergence of new infections have generated considerable interest in the exploration of natural products from plant origins as combination therapy. In this context, crude ethanolic extract (CEE), ethyl acetate fraction (EAF), and methanolic fraction (MF) from Anacardium microcarpum were tested alone or in combination with antibiotics (amikacin, gentamicin, ciprofloxacin, and imipenem) against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Methods Antibiotic resistance-modifying activity was performed using the microdilution method by determining the minimal inhibitory concentration (MIC). In addition, phytochemical prospecting analyses of tested samples were carried out. Results Our results indicated that all the extracts showed low antibacterial activity against multidrug-resistant strains (MIC =512 μg/mL). However, addition of CEE, EAF, and MF to the growth medium at the subinhibitory concentration (MIC/8=64 μg/mL) significantly modulated amikacin- and gentamicin-resistant E. coli 06. CEE and EAF also demonstrated a significant (P<0.001) synergism with imipenem against S. aureus. In contrast, MF antagonized the antibacterial effect of ciprofloxacin and gentamicin against P. aeruginosa 03 and S. aureus 10, respectively. Qualitative phytochemical analysis of the extracts revealed the presence of secondary metabolites including phenols, flavonoids, xanthones, chalcones, and tannin pyrogallates. Conclusion Taken together, our results suggest that A. microcarpum is a natural resource with resistance-modifying antibacterial activity that needs to be further investigated to overcome the present resistant-infection problem. PMID:26604695

  16. Incidence, etiology, and antibiotic resistance patterns of gram-negative microorganisms isolated from patients with ventilator-associated pneumonia in a medical-surgical intensive care unit of a teaching hospital in istanbul, Turkey (2004-2006).

    PubMed

    Erdem, Ilknur; Ozgultekin, Asu; Inan, Asuman Sengoz; Dincer, Emine; Turan, Guldem; Ceran, Nurgul; Ozturk Engin, Derya; Senbayrak Akcay, Seniha; Akgun, Nur; Goktas, Pasa

    2008-09-01

    The identification of microorganisms causing ventilator-associated pneumonia (VAP) is important for formulating appropriate therapies. In this study, we report the incidence, etiology, and antibiotic resistance patterns of Gram-negative microorganisms isolated from patients diagnosed with VAP in our medical-surgical intensive care unit (ICU) during the years 2004-2006. VAP was diagnosed by using the clinical criteria of the Centers for Disease Control and Prevention. Antibiotic resistance patterns of isolated microorganisms were defined by standard methods. The VAP incidence rate was 22.6/1,000 ventilator days. The most frequently isolated pathogens were Acinetobacter spp., methicillin-resistant Staphylococcus aureus, and Pseudomonas aeruginosa. Ninety percent of Acinetobacter spp. isolates were resistant to ceftazidime, 64% to imipenem, and 80% to ciprofloxacin. Fifty-nine percent of P. aeruginosa isolates were resistant to ceftazidime, 32% to imipenem, and 62% to ciprofloxacin. Cefoperazone-sulbactam was the most active agent against Acinetobacter spp. In conclusion, the incidence of VAP and the prevalence of multidrug-resistant microorganisms are quite high in our ICU. Comparison of the resistance rates of isolates demonstrates that certain antibiotic agents are more effective than others.

  17. Resistance patterns of Escherichia coli causing urinary tract infection

    PubMed Central

    Ferdosi-Shahandashti, Elaheh; Javanian, Mostafa; Moradian-Kouchaksaraei, Masoomeh; Yeganeh, Babak; Bijani, Ali; Motevaseli, Elahe; Moradian- Kouchaksaraei, Fatemeh

    2015-01-01

    Background: Urinary tract infection (UTI) is one of the most prevalent infectious diseases and Escherichia coli is its common cause. The aim of this study was to assess the resistance patterns of E.coli in urinary tract infections and to determine the susceptibility of E.coli to commonly used antimicrobials and also to evaluate the options for empirical treatment of UTI. Methods: This study was conducted in the Ayatollah Rouhani Teaching Hospital of Babol Medical Sciences University in North of Iran. Between January of 2013 to December 2013, antimicrobial susceptibility tests were done by disk diffusion and microdilution method. Growth of >=105 cfu/ml was considered as positive urine test. Ten commonly used antibiotics were examined for susceptibility test. Data and the results were collected and analyzed. Results: E.coli grew in 57 urine samples. Imipenem, ofloxacin, ciprofloxacin were the most sensitive antibiotics at 87.7%, 87.7% and 78.9% respectively. Whereas, cotrimoxazole, cefexime, cefotaxcime and ceftriaxone were the most resistant antibiotics. Antibiotic sensitivity of disk diffusion compared minimum inhibitory concentration (MIC) detected by microdilution had the sensitivity, specificity, positive predictive value and negative predictive value of 82%, 98%, 99% and 74%, respectively. Conclusion: Imipenem, ofloxacin and ciprofloxacin should be used in empirical therapy of UTI. PMID:26644881

  18. Multi-drug resistant Pseudomonas aeruginosa keratitis and its effective treatment with topical colistimethate

    PubMed Central

    Chatterjee, Samrat; Agrawal, Deepshikha

    2016-01-01

    The purpose was to evaluate the clinical outcome in multi-drug resistant Pseudomonas aeruginosa (MDR-PA) bacterial keratitis and report the successful use of an alternative antibiotic, topical colistimethate in some of them. The medical records of 12 culture-proven MDR-PA keratitis patients, all exhibiting in vitro resistance by Kirby–Bauer disc diffusion method to ≥ three classes of routinely used topical antibiotics were reviewed. Eight patients were treated with 0.3% ciprofloxacin or ofloxacin, 1 patient with 5% imipenem/cilastatin and 3 patients with 1.6% colistimethate. The outcomes in 8 eyes treated with only fluoroquinolones were evisceration in 4 eyes, therapeutic corneal graft in 1 eye, phthisis bulbi in 1 eye, and no improvement in 2 eyes. The eye treated with imipenem/cilastin required a therapeutic corneal graft. All the three eyes treated with 1.6% colistimethate healed. Colistimethate may prove to be an effective alternative antibiotic in the treatment of MDR-PA keratitis. PMID:27050354

  19. [Resistance to antibiotics in Pseudomonas aeruginosa in Colombian hospitals].

    PubMed

    Villa, Lina M; Cortés, Jorge A; Leal, Aura L; Meneses, Andrés; Meléndez, Martha P

    2013-12-01

    Pseudomonas aeruginosa infections cause high morbidity and mortality. We performed a descriptive analysis of the rates of antibiotic resistance in isolates of P. aeruginosa in 33 hospitals enrolled in a surveillance network in Colombia. The study was conducted between January 2005 and December 2009 .9905 isolates of P. aeruginosa were identified, (4.9% of all strains). In intensive care units (ICU) P. aeruginosa showed an overall resistance to aztreonam, cefepime , ceftazidime, imipenem, meropenem , and piperacillin / tazobactam of 31.8% , 23.9% , 24.8%, 22.5%, 20.3% and 22.3%, respectively. Resistance rates increased for piperacillin/tazobactam, cefepime, and imipenem; remained unchanged for meropenem; and decreased for aminoglycosides, quinolones and ceftazidime. Resistance to one, two and three or more families of antibiotics was found in 17%, 12.5%, and 32.1%, respectively. In samples collected from the wards, the resistance rate was lower but usually over 10%. Antibiotic resistance in P. aeruginosa isolates in hospitalized patients and particularly in those admitted to ICUs in Colombia is high.

  20. Clinical and economic consequences of ventilator-associated pneumonia.

    PubMed

    Amin, Alpesh

    2009-08-15

    Increasing drug resistance rates among gram-negative pathogens that frequently cause ventilator-associated pneumonia have resulted in increased hospital mortality, longer hospital stays, and higher inpatient health care costs. There is an urgent need for effective therapies that lessen the clinical and economic consequences of this nosocomial infection. In a randomized, multicenter, prospective, phase 3 trial, medical resource use associated with doripenem was compared with that associated with imipenem for the treatment of ventilator-associated pneumonia. Analysis of medical resource use revealed that patients who received doripenem had a significantly shorter duration of hospital stay (22 vs. 27 days; P = .01)and duration of mechanical ventilation use (7 vs. 10 days; P = .03) than did patients who received imipenem. In addition, the duration of intensive care unit stay tended to be shorter for patients who received doripenem. The reduced medical resource use achieved with use of doripenem for treatment of ventilator-associated pneumonia may provide not only clinical benefits to patients but also economic benefits to hospitals and health care systems.

  1. Disk Carbapenemase Test for the Rapid Detection of KPC-, NDM-, and Other Metallo-β-Lactamase-Producing Gram-Negative Bacilli

    PubMed Central

    Kim, Hyunsoo; Sung, Ji Yeon; Yong, Dongeun; Jeong, Seok Hoon; Song, Wonkeun; Chong, Yunsop

    2016-01-01

    Background Rapid detection of carbapenemase-producing gram-negative bacilli (GNB) is required for optimal treatment of infected patients. We developed and assessed a new disk carbapenemase test (DCT). Methods Paper disks containing 0.3 mg of imipenem and bromothymol blue indicator were developed, and the performance of the DCT were evaluated by using 742 strains of GNB with or without carbapenemases. Results The paper disks were simple to prepare, and the dried disks were stable at -20℃ and at 4℃. The DCT detected 212 of 215 strains (98.6% sensitivity with 95% confidence interval [CI] 96.0-99.5%) of GNB with known class A (KPC and Sme) and class B (NDM, IMP, VIM, and SIM) carbapenemases within 60 min, but failed to detect GES-5 carbapenemase. The DCT also detected all two Escherichia coli isolates with OXA-48, but failed to detect GNB with OXA-232, and other OXA carbapenemases. The DCT showed 100% specificity (95% CI, 99.2-100%) in the test of 448 imipenem-nonsusceptible, but carbapenemase genes not tested, clinical isolates of GNB. Conclusions The DCT is simple and can be easily performed, even in small laboratories, for the rapid detection of GNB with KPC, NDM and the majority of IMP, VIM, and SIM carbapenemases. PMID:27374708

  2. Multicenter Study of Antimicrobial Susceptibility of Anaerobic Bacteria in Korea in 2012

    PubMed Central

    Lee, Yangsoon; Park, Yeon-Joon; Kim, Mi-Na; Uh, Young; Kim, Myung Sook

    2015-01-01

    Background Periodic monitoring of regional or institutional resistance trends of clinically important anaerobic bacteria is recommended, because the resistance of anaerobic pathogens to antimicrobial drugs and inappropriate therapy are associated with poor clinical outcomes. There has been no multicenter study of clinical anaerobic isolates in Korea. We aimed to determine the antimicrobial resistance patterns of clinically important anaerobes at multiple centers in Korea. Methods A total of 268 non-duplicated clinical isolates of anaerobic bacteria were collected from four large medical centers in Korea in 2012. Antimicrobial susceptibility was tested by the agar dilution method according to the CLSI guidelines. The following antimicrobials were tested: piperacillin, piperacillin-tazobactam, cefoxitin, cefotetan, imipenem, meropenem, clindamycin, moxifloxacin, chloramphenicol, metronidazole, and tigecycline. Results Organisms of the Bacteroides fragilis group were highly susceptible to piperacillin-tazobactam, imipenem, and meropenem, as their resistance rates to these three antimicrobials were lower than 6%. For B. fragilis group isolates and anaerobic gram-positive cocci, the resistance rates to moxifloxacin were 12-25% and 11-13%, respectively. Among B. fragilis group organisms, the resistance rates to tigecycline were 16-17%. Two isolates of Finegoldia magna were non-susceptible to chloramphenicol (minimum inhibitory concentrations of 16-32 mg/L). Resistance patterns were different among the different hospitals. Conclusions Piperacillin-tazobactam, cefoxitin, and carbapemems are highly active β-lactam agents against most of the anaerobes. The resistance rates to moxifloxacin and tigecycline are slightly higher than those in the previous study. PMID:26206683

  3. Identification and antimicrobial susceptibility of Alcaligenes xylosoxidans isolated from patients with cystic fibrosis.

    PubMed

    Saiman, L; Chen, Y; Tabibi, S; San Gabriel, P; Zhou, J; Liu, Z; Lai, L; Whittier, S

    2001-11-01

    In the past decade, potential pathogens, including Alcaligenes species, have been increasingly recovered from cystic fibrosis (CF) patients. Accurate identification of multiply antibiotic-resistant gram-negative bacilli is critical to understanding the epidemiology and clinical implications of emerging pathogens in CF. We examined the frequency of correct identification of Alcaligenes spp. by microbiology laboratories affiliated with American CF patient care centers. Selective media, an exotoxin A probe for Pseudomonas aeruginosa, and a commercial identification assay, API 20 NE, were used for identification. The activity of antimicrobial agents against these clinical isolates was determined. A total of 106 strains from 78 patients from 49 CF centers in 22 states were studied. Most (89%) were correctly identified by the referring laboratories as Alcaligenes xylosoxidans. However, 12 (11%) strains were misidentified; these were found to be P. aeruginosa (n = 10), Stenotrophomonas maltophilia (n = 1), and Burkholderia cepacia (n = 1). Minocycline, imipenem, meropenem, piperacillin, and piperacillin-tazobactam were the most active since 51, 59, 51, 50, and 55% of strains, respectively, were inhibited. High concentrations of colistin (100 and 200 microg/ml) inhibited 92% of strains. Chloramphenicol paired with minocycline and ciprofloxacin paired with either imipenem or meropenem were the most active combinations and inhibited 40 and 32%, respectively, of strains. Selective media and biochemical identification proved to be useful strategies for distinguishing A. xylosoxidans from other CF pathogens. Standards for processing CF specimens should be developed, and the optimal method for antimicrobial susceptibility testing of A. xylosoxidans should be determined.

  4. Detection of metallo-β-lactamase genes in clinically isolated Klebsiella pneumoniae and Klebsiella oxytoca.

    PubMed

    Tateno, Hidetsugu; Yasuhara, Tsutomu; Sugano, Emi; Tahara, Sachiko; Ugajin, Kazuhisa; Fukuchi, Kunihiko

    2014-12-01

    We detected and characterized metallo-β-lactamase genes (blaIMP-1 and blaIMP-11) in third generation cephalosporin-resistant Klebsiella pneumoniae and Klebsiella oxytoca isolated at Showa University Hospital between January 1, 2011 and December 31, 2012. The cephalosporin-resistant K pneumoniae strains were frequently isolated from the urine, while one strain of K. pneumoniae, which was resistant to carbapenem, was isolated from the stool. We analyzed the phenotypes and genotypes of the metallo-β-lactamase genes from the 16 strains of cephalosporin-resistant-K pneumoniae and 6 strains of -K. oxytoca isolated from the same ward. The minimum inhibitory concentrations of imipenem were below 4 µg/ml in 21 out of the 22 isolated strains. The double disc synergy test using ceftazidime and sodium mercaptoacetic acid revealed enlargements in the inhibitory zones of 14 of the 16 strains of K. pneumoniae and all 6 strains of K. oxytoca. Metallo-β-lactamase genes were detected in all of the tested strains, with blaIMP-1 in 3 K. pneumoniae and 1 K. oxytoca, blaIMP-11 in 13 K pneumoniae and 4 K. oxytoca, and both blaIMP-1 and blaIMP-11 in one K. oxytoca. Our results indicate that third generation cephalosporin-resistant and imipenem-susceptible K. pneumoniae and K. oxytoca possess the metallo-β-lactamase gene. The active surveillance of metallo-β-lactamase genes should be performed in clinical laboratories. (Original).

  5. Forsythoside B protects against experimental sepsis by modulating inflammatory factors.

    PubMed

    Jiang, Wang-Lin; Yong-Xu; Zhang, Shu-Ping; Zhu, Hai-Bo; Jian-Hou

    2012-07-01

    The present study investigated the effects of Forsythoside B on an experimental model of sepsis induced by caecal ligation and puncture (CLP) in rats and elucidated the potential mechanism in cultured RAW 264.7 cells. Results showed that Forsythoside B concentration-dependently down-regulated the levels of TNF-α, IL-6 and high-mobility group-box 1 protein (HMGB1) in lipopolysaccharide (LPS)-stimulated RAW264.7 cells, inhibited the IκB kinase (IKK) pathway and modulated nuclear factor (NF)- κB. Intravenous injection (i.v.) of Forsythoside B alone or plus Imipenem reduced serum levels of TNF-α, IL-6, HMGB1, triggering receptor expressed on myeloid cells (TREM-1) and endotoxin, while the serum level of IL-10 was up-regulated and myeloperoxidase (MPO) in lung, liver and small intestine was reduced. Meanwhile, i.v. of Forsythoside B alone or plus Imipenem reduced CLP-induced lethality in rats. These data indicated that the antisepsis effect of Forsythoside B is mediated by decreasing local and systemic levels of a wide spectrum of inflammatory mediators. Its antisepsis mechanism may be that Forsythoside B binds to LPS and reduces the biological activity of serum LPS, and inhibits NF-κB activition. Our studies enhance the case for the use of Forsythoside B in sepsis. Forsythoside B itself has promise as a therapy for the treatment of sepsis in humans.

  6. MUS-2, a novel variant of the chromosome-encoded β-lactamase MUS-1, from Myroides odoratimimus

    PubMed Central

    Al-Bayssari, C.; Gupta, S. Kumar; Dabboussi, F.; Hamze, M.; Rolain, J.-M.

    2015-01-01

    The aim of the present study was to investigate the molecular mechanism of carbapenem resistance of three imipenem-resistant isolates of Myroides odoratimimus recovered from two livestock farms of cows and pigeons by rectal swab in Lebanon in January 2014. Investigation of imipenem resistance of these isolates using the modified Hodge test, the EDTA test, the modified CarbaNP test and the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry Ultraflex assay showed a carbapenemase activity due to the presence of a chromosome-encoded β-lactamase MUS, verified by PCR. However amplification and sequencing of this chromosomal gene showed a novel variant of it designated MUS-2 by the curators of the Lahey database of β-lactamases (http://www.lahey.org/Studies/webt.asp). Cloning of the blaMUS-2 was performed, followed by protein expression in Escherichia coli TOP 10. Pulsed-field gel electrophoresis clearly showed that the three isolates belonged to the same clone. This study reports a novel variant of the chromosome-encoded blaMUS-1 associated with carbapenem resistance in Myroides odoratimimus and shows that animals may represent a reservoir of bacteria harbouring several variants of resistance genes. PMID:26257915

  7. The secondary resistome of multidrug-resistant Klebsiella pneumoniae

    PubMed Central

    Jana, Bimal; Cain, Amy K.; Doerrler, William T.; Boinett, Christine J.; Fookes, Maria C.; Parkhill, Julian; Guardabassi, Luca

    2017-01-01

    Klebsiella pneumoniae causes severe lung and bloodstream infections that are difficult to treat due to multidrug resistance. We hypothesized that antimicrobial resistance can be reversed by targeting chromosomal non-essential genes that are not responsible for acquired resistance but essential for resistant bacteria under therapeutic concentrations of antimicrobials. Conditional essentiality of individual genes to antimicrobial resistance was evaluated in an epidemic multidrug-resistant clone of K. pneumoniae (ST258). We constructed a high-density transposon mutant library of >430,000 unique Tn5 insertions and measured mutant depletion upon exposure to three clinically relevant antimicrobials (colistin, imipenem or ciprofloxacin) by Transposon Directed Insertion-site Sequencing (TraDIS). Using this high-throughput approach, we defined three sets of chromosomal non-essential genes essential for growth during exposure to colistin (n = 35), imipenem (n = 1) or ciprofloxacin (n = 1) in addition to known resistance determinants, collectively termed the “secondary resistome”. As proof of principle, we demonstrated that inactivation of a non-essential gene not previously found linked to colistin resistance (dedA) restored colistin susceptibility by reducing the minimum inhibitory concentration from 8 to 0.5 μg/ml, 4-fold below the susceptibility breakpoint (S ≤ 2 μg/ml). This finding suggests that the secondary resistome is a potential target for developing antimicrobial “helper” drugs that restore the efficacy of existing antimicrobials. PMID:28198411

  8. Carbapenem Resistance among Enterobacter Species in a Tertiary Care Hospital in Central India

    PubMed Central

    Khajuria, Atul; Praharaj, Ashok Kumar; Kumar, Mahadevan; Grover, Naveen

    2014-01-01

    Objective. To detect genes encoding carbapenem resistance among Enterobacter species in a tertiary care hospital in central India. Methods. Bacterial identification of Enterobacter spp. isolates from various clinical specimens in patients admitted to intensive care units was performed by routine conventional microbial culture and biochemical tests using standard recommended techniques. Antibiotic sensitivity test was performed by standard Kirby Bauer disc diffusion technique. PCR amplification and automated sequencing was carried out. Transfer of resistance genes was determined by conjugation. Results. A total of 70/130 (53.84%) isolates of Enterobacter spp. were found to exhibit reduced susceptibility to imipenem (diameter of zones of inhibition ≤13 mm) by disc diffusion method. Among 70 isolates tested, 48 (68.57%) isolates showed MIC values for imipenem and meropenem ranging from 32 to 64 mg/L as per CLSI breakpoints. All of these 70 isolates were found susceptible to colistin in vitro as per MIC breakpoints (<0.5 mg/L). PCR carried out on these 48 MBL (IP/IPI) E-test positive isolates (12 Enterobacter aerogenes, 31 Enterobacter cloacae, and 05 Enterobacter cloacae complex) was validated by sequencing for beta-lactam resistance genes and result was interpreted accordingly. Conclusion. The study showed MBL production as an important mechanism in carbapenem resistance in Enterobacter spp. and interspecies transfer of these genes through plasmids suggesting early detection by molecular methods. PMID:25180095

  9. Multicenter evaluation of antimicrobial resistance to six broad-spectrum beta-lactams in Colombia: comparison of data from 1997 and 1998 using the Etest method. The Colombian Antimicrobial Resistance Study Group.

    PubMed

    Pfaller, M A; Jones, R N; Doern, G V; Salazar, J C

    1999-11-01

    The minimum inhibitory concentrations of six broad-spectrum beta-lactam antimicrobial agents were determined in 1998 by use of the Etest versus a total of 823 bacteria in 11 Colombian hospital laboratories. These data were compared with results of a similar study conducted in 1997. The organisms tested included 532 recent clinical isolates of Enterobacteriaceae, 108 Pseudomonas aeruginosa, 94 Acinetobacter species, and 89 oxacillin-susceptible Staphylococcus aureus. Extended-spectrum beta-lactamase production was noted among 27.8 to 33.9% of Escherichia coli isolates and 41.7 to 46.7% of Klebsiella spp. isolates. Hyperproduction of Amp C cephalosporinases was observed with 10.5 to 31.4% of isolates of Enterobacter spp., Serratia spp., and Citrobacter spp. An increase in resistance to all of the beta-lactams was observed among Enterobacteriaceae, Acinetobacter spp. and P. aeruginosa when 1998 results were compared with those obtained in 1997. The overall rank order of activity of the six beta-lactams tested in 1998 versus all clinical isolates was imipenem (93.2% susceptible) > cefoperazone/sulbactam (84.1%) > cefepime (80.9%) > ceftazidime (70.7%) > aztreonam (65.7%) > cefotaxime (65.6%). In contrast, the rank order of these same agents tested against a similar collection of Colombian isolates in 1997 was imipenem (96.6% susceptible) > cefepime (93.6%) > cefoperazone/sulbactam (90.5%) > cefotaxime (74.9%) > aztreonam (74.3%) > ceftazidime (73.2%).

  10. Effectiveness of Antipseudomonal Antibiotics and Mechanisms of Multidrug Resistance in Pseudomonas aeruginosa.

    PubMed

    El ZOWALATYl, Mohamed E; Gyetvaii, Bpla

    2016-01-01

    Pseudomonas aeruginosa is a leading human pathogen that causes serious infections at various tissues and organs leading to life threatening health problems and possible deadly outcomes. Resistance patterns vary widely whether it is from hospitals or community acquired infections. Reporting resistance profiles to a certain antibiotics provide valuable information in a given setting, but may be extrapolated outside the sampling location. In the present study, P. aeruginosa isolates were screened to determine their susceptibilities against anti-pseudomonal antimicrobial agents and possible existing mechanisms of resistance were determined. Eighty-six isolates of P. aeruginosa were recovered. Isolates representing different resistance profiles were screened for the existence of three different resistance mechanisms including drug inactivation due to metallo-β-lactamases, drug impermeability by outer membrane proteins and drug efflux. All tested isolates showed uniform susceptibility (100%, n = 86/86) to piperacillin, meropenem, amikacin, and polymyxin B. A single isolate was found to be imipenem resistant (99%, n = 85/86). The possible mechanisms of resistance of P. aeruginosa to imipenem involve active drug efflux pumps, outer membrane impermeability as well as drug inactivating enzymes. These findings demonstrate the fundamental importance of the in vitro susceptibility testing of antibiotics prior to antipseudomonal therapy and highlight the need for a continuous antimicrobial resistance surveillance programs to monitor the changing resistance patterns so that clinicians and health care officials are updated as to the most effective therapeutic agents to combat the serious outcomes of P. aeruginosa infections.

  11. Antimicrobial Susceptibility of Escherichia coli Isolated from Fresh-Marketed Nile Tilapia (Oreochromis niloticus)

    PubMed Central

    Rocha, Rafael dos Santos; Leite, Lana Oliveira; de Sousa, Oscarina Viana; Vieira, Regine Helena Silva dos Fernandes

    2014-01-01

    The contamination of seafood by bacteria of fecal origin, especially Escherichia coli, is a widely documented sanitary problem. The objective of the present study was to isolate E. coli strains from the gills, muscle, and body surface of farmed Nile tilapias (Oreochromis niloticus) fresh-marketed in supermarkets in Fortaleza (Ceará, Brazil), to determine their susceptibility to antibiotics of different families (amikacin, gentamicin, imipenem, cephalothin, cefotaxime, ciprofloxacin, aztreonam, ampicillin, nalidixic acid, tetracycline, and sulfametoxazol-trimetoprim), and to determine the nature of resistance by plasmid curing. Forty-four strains (body surface = 25, gills = 15, muscle = 4) were isolated, all of which were susceptible to amikacin, aztreonam, cefotaxime, ciprofloxacin, gentamicin, and imipenem. Gill and body surface samples yielded 11 isolates resistant to ampicillin, tetracycline, and sulfametoxazol-trimetoprim, 4 of which of plasmidial nature. The multiple antibiotic resistance index was higher for strains isolated from body surface than from gills. The overall high antibiotic susceptibility of E. coli strains isolated from fresh-marketed tilapia was satisfactory, although the occasional finding of plasmidial resistance points to the need for close microbiological surveillance of the farming, handling, and marketing conditions of aquaculture products. PMID:24808957

  12. The secondary resistome of multidrug-resistant Klebsiella pneumoniae.

    PubMed

    Jana, Bimal; Cain, Amy K; Doerrler, William T; Boinett, Christine J; Fookes, Maria C; Parkhill, Julian; Guardabassi, Luca

    2017-02-15

    Klebsiella pneumoniae causes severe lung and bloodstream infections that are difficult to treat due to multidrug resistance. We hypothesized that antimicrobial resistance can be reversed by targeting chromosomal non-essential genes that are not responsible for acquired resistance but essential for resistant bacteria under therapeutic concentrations of antimicrobials. Conditional essentiality of individual genes to antimicrobial resistance was evaluated in an epidemic multidrug-resistant clone of K. pneumoniae (ST258). We constructed a high-density transposon mutant library of >430,000 unique Tn5 insertions and measured mutant depletion upon exposure to three clinically relevant antimicrobials (colistin, imipenem or ciprofloxacin) by Transposon Directed Insertion-site Sequencing (TraDIS). Using this high-throughput approach, we defined three sets of chromosomal non-essential genes essential for growth during exposure to colistin (n = 35), imipenem (n = 1) or ciprofloxacin (n = 1) in addition to known resistance determinants, collectively termed the "secondary resistome". As proof of principle, we demonstrated that inactivation of a non-essential gene not previously found linked to colistin resistance (dedA) restored colistin susceptibility by reducing the minimum inhibitory concentration from 8 to 0.5 μg/ml, 4-fold below the susceptibility breakpoint (S ≤ 2 μg/ml). This finding suggests that the secondary resistome is a potential target for developing antimicrobial "helper" drugs that restore the efficacy of existing antimicrobials.

  13. Antibiotic prescription and cost patterns in a general intensive care unit

    PubMed Central

    Krivoy, Norberto; El-Ahal, Wissam Abed; Bar-Lavie, Yaron; Haddad, Salim

    Antibiotic prescription habits, cost pattern, and the prospective intervention in an Intensive Care Unit were analyzed. Methods Data on antibiotic utilization and costs were collected prospectively from individual electronic charts from August 2003 to January 2004, and retrospectively from August to December 2002. Results A total of 180 and 107 patients were surveyed in 2002 and 2003. In 2002, Piperacillin-Tazobactam (13.8%) and Imipenem/Cilastin (11.2%) were the most prescribed medications; while, in 2003, Vancomycin (12.6%) and Imipenem/Cilastin (11.3%) were prescribed, respectively. Total defined daily dose (DDD) and Drug Utilization 90% (DU90%) index for 2002 and 2003 were 2031.15 and 2325.90 DDDs (p>0.1) and 1777.57 and 2079.61 DU90%, respectively (p>0.1). The Median Total Cost /100 admission days (CI 95%) were NIS13,310 (11,110;18,420) and NIS13,860 (6,710;18,020) (p=0.66), respectively. Conclusions Interventional programs should focus on promoting infectious control with rational antibiotic prescription aimed at minimizing the future emergence of bacterial resistance and futile expenses. PMID:25214920

  14. Correlation between penicillin-binding protein 2 mutations and carbapenem resistance in Escherichia coli.

    PubMed

    Yamachika, Shinichiro; Sugihara, Chika; Kamai, Yasuki; Yamashita, Makoto

    2013-03-01

    It is well known that carbapenem-resistant mutations in penicillin-binding proteins (PBPs) are not observed in most Gram-negative bacteria under either clinical or experimental conditions. To understand the mechanisms involved in carbapenem resistance, this study constructed a mutS- and tolC-deficient Escherichia coli strain, which was expected to have elevated mutation frequencies and to lack drug efflux. Using this mutant, carbapenem-resistant strains with target mutations were successfully and efficiently isolated. The mutations T547I/A, M574I and G601D were identified in the PBP2 gene. Meropenem (MEPM)-resistant strains with the PBP2 T547I mutation showed fourfold increased resistance to 1-β-methyl-substituted carbapenems, such as doripenem, MEPM and biapenem, but not to non-substituted carbapenems such as imipenem and panipenem and other β-lactams. In addition, resistance resulting from the G601D mutation was limited to MEPM, whilst the M574I mutation conferred resistance to MEPM, imipenem and panipenem. This is the first report, to the best of our knowledge, that E. coli also has a carbapenem-resistance mechanism as a result of PBP2 mutations, and it provides insight into the resistance profiles of PBP2 mutations to carbapenems with and without the 1-β-methyl group.

  15. An in-vitro study of carbapenem-induced morphological changes and endotoxin release in clinical isolates of gram-negative bacilli.

    PubMed

    Horii, T; Kobayashi, M; Sato, K; Ichiyama, S; Ohta, M

    1998-04-01

    One hundred clinical isolates, including Escherichia coli, Serratia marcescens, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus vulgaris and Proteus mirabilis, were exposed to carbapenems (imipenem, panipenem, meropenem and biapenem) at 0.5 x MIC for 3 h, then their morphology was examined and endotoxin release determined. Ceftazidime, which induces filament formation, was used as a control. Scanning electron microscopy showed that these carbapenems induced formation of spherical or ovoid cells, except for P. aeruginosa treated with meropenem and biapenem; these latter cells had a 'bulge' midway along them and we have termed them 'oval-centred'. There was a relationship between morphology and the amount of endotoxin released following exposure to carbapenems or ceftazidime. Of all the species investigated, P. aeruginosa showed the most variable morphological changes. P. aeruginosa exposed to biapenem were longer oval-centred in shape, and released significantly more endotoxin than those exposed to imipenem, panipenem (spherical) or meropenem (shorter oval-centred cells) (P=0.030, 0.017 and 0.002, respectively). In all strains except P. aeruginosa, carbapenems induced significantly less endotoxin release than ceftazidime (P < 0.05).

  16. Antibiotic Resistance Pattern and Evaluation of Metallo-Beta Lactamase Genes Including bla- IMP and bla- VIM Types in Pseudomonas aeruginosa Isolated from Patients in Tehran Hospitals.

    PubMed

    Aghamiri, Samira; Amirmozafari, Nour; Fallah Mehrabadi, Jalil; Fouladtan, Babak; Samadi Kafil, Hossein

    2014-01-01

    Beta-lactamase producing strains of Pseudomonas aeruginosa are important etiological agents of hospital infections. Carbapenems are among the most effective antibiotics used against Pseudomonas infections, but they can be rendered infective by group B β -lactamase, commonly called metallo-beta lactamase. In this study, the antimicrobial sensitivity patterns of P. aeruginosa strains isolated from 9 different hospitals in Tehran, Iran, as well as the prevalence of MBLs genes (bla- VIM and bla- IMP ) were determined. A total of 212 strains of P. aeruginosa recovered from patients in hospitals in Tehran were confirmed by both biochemical methods and PCR. Their antimicrobial sensitivity patterns were determined by Kirby-Bauer disk diffusion method. Following MIC determination, imipenem resistant strains were selected by DDST method which was followed by PCR tests for determination of MBLs genes: bla- IMP and bla- VIM . The results indicated that, in the DDST phenotypic method, among the 100 imipenem resistant isolates, 75 strains were MBLs positive. The PCR test indicated that 70 strains (33%) carried bla- VIM gene and 20 strains (9%) harbored bla- IMP . The results indicated that the extent of antibiotic resistance among Pseudomonas aeruginosa is on the rise. This may be due to production of MBLs enzymes. Therefore, determination of antibiotic sensitivity patterns and MBLs production by these bacteria, can be important in control of clinical Pseudomonas infection.

  17. Bisthiazolidines: A Substrate-Mimicking Scaffold as an Inhibitor of the NDM-1 Carbapenemase.

    PubMed

    González, Mariano M; Kosmopoulou, Magda; Mojica, Maria F; Castillo, Valerie; Hinchliffe, Philip; Pettinati, Ilaria; Brem, Jürgen; Schofield, Christopher J; Mahler, Graciela; Bonomo, Robert A; Llarrull, Leticia I; Spencer, James; Vila, Alejandro J

    2015-11-13

    Pathogenic Gram-negative bacteria resistant to almost all β-lactam antibiotics are a major public health threat. Zn(II)-dependent or metallo-β-lactamases (MBLs) produced by these bacteria inactivate most β-lactam antibiotics, including the carbapenems, which are "last line therapies" for life-threatening Gram-negative infections. NDM-1 is a carbapenemase belonging to the MBL family that is rapidly spreading worldwide. Regrettably, inhibitors of MBLs are not yet developed. Here we present the bisthiazolidine (BTZ) scaffold as a structure with some features of β-lactam substrates, which can be modified with metal-binding groups to target the MBL active site. Inspired by known interactions of MBLs with β-lactams, we designed four BTZs that behave as in vitro NDM-1 inhibitors with Ki values in the low micromolar range (from 7 ± 1 to 19 ± 3 μM). NMR spectroscopy demonstrated that they inhibit hydrolysis of imipenem in NDM-1-producing Escherichia coli. In vitro time kill cell-based assays against a variety of bacterial strains harboring blaNDM-1 including Acinetobacter baumannii show that the compounds restore the antibacterial activity of imipenem. A crystal structure of the most potent heterocycle (L-CS319) in complex with NDM-1 at 1.9 Å resolution identified both structural determinants for inhibitor binding and opportunities for further improvements in potency.

  18. Breakpoints for carbapenemase-producing Enterobacteriaceae: is the problem solved?

    PubMed

    Cantón, Rafael; Canut, Andrés; Morosini, María Isabel; Oliver, Antonio

    2014-12-01

    The imipenem and meropenem breakpoints for Enterobacteriaceae established by the Clinical and Laboratory Standards Institute (CLSI) are somewhat lower than those established by the European Committee on Antimicrobial Susceptibility Testing (EUCAST), but are identical for ertapenem and doripenem. The differences are primarily due to the various pharmacokinetic/pharmacodynamic (PK/PD) approaches used to define these breakpoints. Both approaches use the Monte Carlo simulation with a probability of target attainment (PTA) for reaching the PD target of free drug concentration above the minimum inhibitory concentration (MIC) at least 40% of the time (~40%fT >MIC). EUCAST uses PTA mean values with confidence intervals (CIs) of 95% and 99%, whereas the CI used by CLSI is 90%. In addition, CLSI uses an "inflated variance" that takes into account the variability of PK parameters in various types of patients, particularly those who are critically ill. By employing this approach, the susceptible CLSI breakpoint captures a higher number of carbapenemase-producing Enterobacteriaceae (CPE) than EUCAST. EUCAST, however, has recently defined cut-off values for screening CPE. Both committees recommend reporting carbapenem susceptibility results "as tested," demonstrating carbapenemase production only for epidemiological purposes and infection control. New clinical data could potentially modify this recommendation because carbapenemase production also influences specific treatment guidance concerning carbapenems in combination with other antimicrobials in infections due to CPE. This advice should not be followed when imipenem or meropenem MICs are >8mg/L, which is coincident with the EUCAST resistant breakpoints for these carbapenems.

  19. Clinical pharmacology of carbapenems in neonates.

    PubMed

    Pacifici, Gian Maria; Allegaert, Karel

    2014-04-01

    Carbapenems are an effective tool to treat complicated bacterial infections. This review aims to summarize the available information on carbapenems in neonates to guide clinicians on drug choice and indications in neonates. Moreover, identification of knowledge gaps may stimulate researchers to design studies to further improve pharmacotherapy in neonates. To do so, a bibliographic search [infant/newborn and meropenem, imipenem, panipenem, ertapenem, doripenem or imipenem] was performed (PubMed, EMBASE) and public clinical trial registries (clinicaltrials.gov, EU registry) were searched to summarize the available information. Carbapenem clearance in neonates is low. Variability relates to maturation (weight, age) and renal function (creatinine clearance), while observations in neonates with renal failure are absent. Pharmacodynamics are almost exclusively limited to meropenem, and the available information will further increase (NeoMero-1-2, necrotizing enterocolitis, meningitis). Finally, there are also some ongoing doripenem pharmacokinetics (PK) studies in neonates. It was concluded that observations on carbapenems in neonates are limited, but studies (NeoMero, doripenem) are ongoing. Until this information becomes available, off label prescription of meropenem seems to be the most reasonable choice when a carbapenem is appropriate. Knowledge gaps relate to PK in neonates with renal failure and to the potential benefit of prolonged compared to short duration of infusion.

  20. Microbial Etiology and Antimicrobial Susceptibility of Bactria Implicated in Urinary Tract Infection in Tehran, Iran

    PubMed Central

    Nozarian, Zohreh; Abdollahi, Alireza

    2015-01-01

    Background and Objectives: Urinary tract infections (UTI) are one of the most common infectious diseases with different microbial agent and antimicrobial resistant pattern in hospitalized patients and outpatients. In order to assess the adequacy of therapy, knowledge of prevalence and resistance pattern of the bacteria is necessary. The main aim of this study was to evaluate the prevalence and the antimicrobial resistance pattern of main bacterial responsible for UTI in order to establish an appropriate empirical therapy. Methods: All urine samples were referred to Imam Hospital Laboratory, Tehran, Iran during 2011-2012, urine culture isolated and bacteria were identified and the profile of antibiotic susceptibility was characterized. Result: From 1851 urine cultures, UTI was more frequent in woman (68%) E. coli was as usual the most common pathogen implicated in UTI. Most susceptibility was to imipenem (98.9%). nitroforantoin (96%) and amikacin (94.1%) and increased resistance to penicillin (66.6%), nalidixic acid (62.1%) ampicilin (60.1%) and cotrimoxazole 54.3%. Discussion: The most common isolated pathogen was E. coli . According to antibiogram susceptibility, the recommended antimicrobial drugs are nitroforantoin and imipenem. nalidixic acid and cotrimoxazole are not recommended because drug resistance is high. PMID:26516326

  1. [Evolution of antimicrobial susceptibility of Acinetobacter baumannii clinical isolates].

    PubMed

    López-Hernández, S; Alarcón, T; López-Brea, M

    2000-12-01

    Acinetobacter baumannii is a microorganism frequently implicated in colonization and infection in hospitalized patients. An increase of resistance has been observed in recent years making these infections difficult to treat. The in vitro activity of 24 antibiotics, 15 betalactam agents and nine nonbetalactams, was studied in 156 A. baumannii clinical isolates. The strains were collected from different clinical samples obtained from inpatients (92%) and 8% were from outpatients. Evolution of susceptibility from January 1995 to December 1997 was studied. MIC of the following antibiotics was determined by the agar dilution method: ampicillin, ticarcillin, piperacillin, ampicillin-sulbactam, amoxicillin- clavulanic acid, ticarcillin-clavulanic acid, piperacillin-tazobactam, cefotaxime, ceftazidime, cefepime, imipenem, meropenem, clavulanic acid, sulbactam, tazobactam, amikacin, gentamicin, tobramycin, ofloxacin, doxycycline, fosfomycin, rifampin, azithromycin and colistin. Low antimicrobial susceptibility was observed in most A. baumannii strains. Colistin, imipenem, meropenem and ampicillin-sulbactam showed the greatest susceptibility (100, 88.4, 88.4 and 84.6%, respectively). A. baumannii strains from inpatients showed a lower antimicrobial susceptibility than strains from outpatients, who showed a high percentage of susceptibility to most antibiotics. Rifampin and azithromycin showed certain in vitro activity against the most susceptible A. baumannii strains. A progressive decrease in susceptibility to most antibiotics was observed during the period studied. Carbapenem-resistant A. baumannii emerged in 1996 and increased in 1997.

  2. Antibiotic susceptibility profile of bacilli isolated from the skin of healthy humans.

    PubMed

    Tarale, Prashant; Gawande, Sonali; Jambhulkar, Vinay

    2015-01-01

    In the present work, twelve bacilli were isolated from four different regions of human skin from Bela population of Nagpur district, India. The isolated bacilli were identified by their morphological, cultural and biochemical characteristics. Seven isolates were Gram negative rods, out of which five were belong to genus Pseudomonas. Three among the five Gram positive isolates were identified as Dermabactor and the remaining two Bacillus. Their antimicrobial susceptibility profile was determined by Kirby-Bauer disc diffusion method. The isolates showed resistance to several currently used broad-spectrum antibiotics. The Dermabactor genus was resistant to vancomycin, although it was earlier reported to be susceptible. Imipenem was found to be the most effective antibiotic for Pseudomonas while nalidixic acid, ampicillin and tetracycline were ineffective. Isolates of Bacillus displayed resistance to the extended spectrum antibiotics cephalosporin and ceftazidime. Imipenem, carbenicillin and ticarcillin were found to be the most effective antibiotics as all the investigated isolates were susceptible to them. Antibiotic resistance may be due to the overuse or misuse of antibiotics during the treatment, or following constant exposure to antibiotic-containing cosmetic formulations.

  3. Ultrastructural Changes in Clinical and Microbiota Isolates of Klebsiella pneumoniae Carriers of Genes bla SHV, bla TEM, bla CTX-M, or bla KPC When Subject to β-Lactam Antibiotics.

    PubMed

    Veras, Dyana Leal; Lopes, Ana Catarina de Souza; da Silva, Grasielle Vaz; Gonçalves, Gabriel Gazzoni Araújo; de Freitas, Catarina Fernandes; de Lima, Fernanda Cristina Gomes; Maciel, Maria Amélia Vieira; Feitosa, Ana Paula Sampaio; Alves, Luiz Carlos; Brayner, Fábio André

    2015-01-01

    The aim of this study was to characterize the ultrastructural effects caused by β-lactam antibiotics in Klebsiella pneumoniae isolates. Three K. pneumoniae clinical isolates were selected for the study with resistance profiles for third-generation cephalosporins, aztreonam, and/or imipenem and with different resistance genes for extended-spectrum β-lactamases (ESBL) or Klebsiella pneumoniae carbapenemase (KPC). Two K. pneumoniae isolates obtained from the microbiota, which were both resistant to amoxicillin and ampicillin, were also analyzed. In accordance with the susceptibility profile, the clinical isolates were subjected to subminimum inhibitory concentrations (sub-MICs) of cefotaxime, ceftazidime, aztreonam, and imipenem and the isolates from the microbiota to ampicillin and amoxicillin, for analysis by means of scanning and transmission electron microscopy. The K. pneumoniae isolates showed different morphological and ultrastructural changes after subjection to β-lactams tested at different concentrations, such as cell filamentation, loss of cytoplasmic material, and deformation of dividing septa. Our results demonstrate that K. pneumoniae isolates harboring different genes that encode for β-lactamases show cell alterations when subjected to different β-lactam antibiotics, thus suggesting that they possess residual activity in vitro, despite the phenotypic resistance presented in the isolates analyzed.

  4. Novel genetic environment of the plasmid-mediated KPC-3 gene detected in Escherichia coli and Citrobacter freundii isolates from China.

    PubMed

    Li, G; Wei, Q; Wang, Y; Du, X; Zhao, Y; Jiang, X

    2011-04-01

    The imipenem and meropenem-resistant strains Citrobacter freundii HS70 and Escherichia coli HS510 were isolated from patients in Shanghai, China. By isoelectric focusing, PCR amplification and sequencing, these strains were each found to produce four β-lactamases: TEM-1, KPC-3, SHV-7 and CTX-M-14. A conjugation experiment and plasmid restriction digestion revealed that the bla (KPC-3) gene was located on the same plasmid in both isolates. Bidirectional primer walking sequencing showed that the nucleotide sequence surrounding the 3.8 kb bla(KPC-3) contained a 671-bp insertion similar to that previously characterized in China. The insertion was located between the promoter and the coding region of the bla(KPC-3) gene. Susceptibility testing performed on recombinant strains carrying the bla(KPC-3) gene with or without the insertion revealed that minimum inhibitory concentrations of imipenem, meropenem, cefepime, and cefotaxime for E. coli EMU-KPC3 (without insertion) were four times higher than that of E. coli EKPC3 (with insertion). The 671 bp insertion reduced bla(KPC-3) expression significantly. Taken together, these results suggest that KPC-3-producing C. freundii and E. coli have begun to emerge in our hospital.

  5. Multidrug-resistant bacteria among patients with ventilatorassociated pneumonia in an emergency intensive care unit, Egypt.

    PubMed

    Azzab, Magda M; El-Sokkary, Rehab H; Tawfeek, Mohamed M; Gebriel, Manar G

    2017-02-01

    Ventilator-associated pneumonia (VAP) is the most common hospital-acquired infection among mechanically ventilated patients. Our objectives were to determine the incidence of VAP, isolate multidrug-resistant bacteria, identify the most prevalent resistant strains and identify their antibiotic susceptibility pattern. The VAP rate was calculated. The isolated microbes were identified and tested for antibiotic susceptibilities. The minimum inhibitory concentrations were determined of imipenem, meropenem and ertapenem for Klebsiella isolates. Klebsiella isolates resistant to carbapenems were tested for the presence of the blaKPC gene. The VAP incidence density rate was 48.8 incidences/1 000 ventilator days. The most common Gram-positive organism was Staphylococcus aureus, of which 86.6% of isolates were resistant to cefoxitin , but 100% were sensitive to teicoplanin, linezolid and tigecycline. The most common Gram-negative bacillus was Klebsiella, of which 94.6% of isolates were resistant to cefotaxime, 70.2% to imipenem, and 64.9% to ertapenem, but 100% were sensitive to colistin and 94.6% were sensitive to tigecycline. Of the carbapenem-resistant Klebsiella strains, 23.1% had the blaKPC gene. The high rates of VAP and the high rates of resistance among isolated organisms point to improper implementation of infection control programmes.

  6. Rhodococcus equi infection in HIV-positive subjects: a retrospective analysis of 24 cases.

    PubMed

    Arlotti, M; Zoboli, G; Moscatelli, G L; Magnani, G; Maserati, R; Borghi, V; Andreoni, M; Libanore, M; Bonazzi, L; Piscina, A; Ciammarughi, R

    1996-01-01

    Rhodococcus equi causes a rare infection in immunocompromised hosts. We describe 24 cases of infection in patients with AIDS-related complex (ARC)/acquired immunodeficiency syndrome (AIDS). Pneumonia was always the first manifestation of R. equi infection, but extrapulmonary involvement was also observed. The main sources of bacteria were sputum, bronchial washings and blood. The strains isolated were mainly susceptible to erythromycin, vancomycin, teicoplanin, rifampicin, imipenem and aminoglycosides. Initial treatment should involve an intravenously administered antibiotic combination therapy including imipenem or vancomycin or teicoplanin, followed by orally administered maintenance combination therapy. Drug combinations should be investigated for serum bactericidal activity in vitro. Surgery does not increase survival time and should only be performed in cases that do not respond to antibiotic treatment. Presumptive risks of infection (contact with horses or farm dust, or cohabiting with people affected by R. equi infection) were present in more than 50% of patients. This finding, and the frequency of bacteria in the sputum, are not sufficient proof of transmission between humans, but do suggest the need for respiratory isolation of patients affected by R. equi pneumonia.

  7. Evaluation of Enterococcus faecalis clinical isolates with 'penicillin-resistant, ampicillin-susceptible' phenotype as reported by Vitek-2 Compact system.

    PubMed

    Tan, Yen Ee; Ng, Lily S Y; Tan, Thean Yen

    2014-10-01

    It has been recently reported that ampicillin susceptibility cannot accurately predict piperacillin and imipenem susceptibilities in penicillin-resistant, ampicillin-susceptible (Pen-R, Amp-S) Enterococcus faecalis isolates, contrary to the current Clinical and Laboratory Standards Institute (CLSI) recommendations. This has important therapeutic implications. Such isolates were noted after the use of Vitek-2 Compact system AST-GP67 susceptibility cards in a Singapore general hospital and they were increasing in numbers. The primary aim of this study was to evaluate these clinical isolates against microbroth dilution (MBD) technique and other commonly used antimicrobial susceptibility test (AST) methods for penicillin and ampicillin. The secondary aim was to evaluate whether ampicillin susceptibility could indeed be a reliable surrogate marker for piperacillin and imipenem susceptibilities in E. faecalis isolates that were confirmed Pen-R, Amp-S.From 2009 to 2013, a total of 49 isolates (5%) of 983 non-duplicate E. faecalis tested by Vitek-2 displayed the 'Pen-R, Amp-S' phenotype in a general hospital in Singapore. These were tested against MBD which was the reference method, Etest and disc diffusion for penicillin and ampicillin. Susceptibilities to piperacillin and imipenem were also tested using MBD. In addition, β-lactamase production test was performed. Forty E. faecalis isolates with penicillin-susceptible, ampicillin-susceptible (Pen-S, Amp-S) phenotype were included for comparative purposes.The categorical agreement rate was 100% for all AST methods in ampicillin reporting for the 'Pen-R, Amp-S' group of E. faecalis isolates. However, a large number of isolates (46 isolates, 93.9%) fell into the major error category for penicillin testing by the Vitek-2 system. Penicillin minimum inhibitory concentrations (MICs) generated by the Vitek-2 system for the majority of these isolates were two doubling dilutions higher compared to those obtained by the reference

  8. [In vitro antibacterial activity of a new parenteral penem, sulopenem].

    PubMed

    Yoshida, T; Tateda, E; Hiramatsu, K; Yokota, T

    1996-04-01

    Eighty percent minimum inhibitory concentrations (MIC80) of sulopenem against clinically isolated 12 to 80 strains of each of different bacteria were as follows: methicillin-susceptible Staphylococcus aureus (MSSA): 0.20 micrograms/ml, methicillin-resistant S. aureus (MRSA): 50 micrograms/ml, coagulase-negative staphylococci: 3.13 micrograms/ml, Streptococcus pyogenes: < or = 0.013 microgram/ml, Streptococcus pneumoniae: < or = 0.013 microgram/ml, beta-streptococci: 0.05 microgram/ml, Enterococcus faecalis: 12.5 micrograms/ml, Enterococcus faecium: > 100 micrograms/ml, Escherichia coli CS2(R+): 0.10 microgram/ml, Klebsiella pneumoniae: 0.05 microgram/ml, Proteus mirabilis: 0.10 microgram/ml, Proteus vulgaris: 0.20 microgram/ml, Morganella morganii: 0.39 micrograms/ml, Providencia rettgeri: 3.13 micrograms/ml, Citrobacter freundii: 0.20 microgram/ml, Enterobacter cloacae: 0.39 microgram/ml, Serratia marcescens: 1.56 micrograms/ml, Pseudomonas aeruginosa: 50 micrograms/ml, Pseudomonas cepacia: 3.13 micrograms/ml, Xanthomonas maltophilia: > 100 micrograms/ml, Acinetobacter calcoaceticus: 1.56 micrograms/ml, ampicillin-resistant Haemophilus influenzae: 0.39 microgram/ml and Bacteroides fragil is: 0.20 microgram/ml, respectively. Sulopenem possesses a stronger activity than flomoxef or cefuzonam against Gram-positive bacteria, the strongest activity among the antibiotics tested against Gram-negative bacteria except P. aeruginosa. Sulopenem has stronger affinities than imipenem to all fractions of PBPs of S. aureus, E. coli, P. vulgaris, S. marcescens, even of P. aeruginosa. Affinities of sulopenem to PBPs-1 and -3 of S. aureus, PBP-2 of E. coli were much stronger than those of imipenem (IPM). Sulopenem generally has small Ki values to all types of beta-lactamases and also has stronger permanent inactivation effect to Ia and IIb types of beta-lactamases than IPM. No synergistic bactericidal activity of sulopenem was apparent with serum complement. However, synergism of

  9. Antibiotic susceptibility pattern and identification of extended spectrum β-lactamases (ESBLs) in clinical isolates of Klebsiella pneumoniae from Shiraz, Iran

    PubMed Central

    Mansury, Davood; Motamedifar, Mohammad; Sarvari, Jamal; Shirazi, Babak; Khaledi, Azad

    2016-01-01

    Background and Objectives: Klebsiella pneumoniae, one of the important causes of nosocomial infections, is the most common extended spectrum β-lactamases (ESBLs) producing organism. ESBLs are defined as the enzymes capable of hydrolyzing oxyimino-cephalosporins, monobactams and carbapenems. The aims of this study were to identify ESBL-producing K. pneumoniae isolates and detect their antibiotic susceptibility pattern. Materials and Methods: This cross-sectional study was conducted from December 2012 to May 2013 in teaching hospitals in Shiraz. Clinical specimens from the urine, sputum, wound, blood, throat, and body fluids were isolated and identified as K. pneumoniae. Antibacterial susceptibility testing was performed for 14 antibiotics using disk diffusion method according to CLSI guidelines. Isolates showing resistant to at least one of the β-lactam antibiotics were then evaluated for production of β-lactamase enzymes using E-test ESBL and combined disk Method. Also, MICs for ceftazidime and imipenem were determined using E-test. The presence of the blaSHV, blaTEM, blaPER and blaCTX-M genes was assessed by PCR. Results: Of 144 K. pneumoniae isolates from different specimens, 38 (26.3 %) was identified as ESBL producer by phenotypic confirmatory test. All ESBL producing isolates were susceptible to imipenem and meropenem and resistant to aztreonam. The highest rate of resistance belonged to amoxicillin (100%), cefotaxime (50%) and gentamicin (42.3%) and the lowest rates were seen for meropenem (11.8%), imipenem and amikacin (both 15.9%). Sixty-two isolates had MICs≥ 4 μg/mL for ceftazidime, of which 38 were positive for ESBLs in phenotypic confirmatory tests (PCT). The prevalence of blaSHV, blaCTX-M, and blaTEM genes among these isolates were 22.2%, 19% and 16%. blaPER was not detected in the studied isolates. Conclusions: Due to the relatively high prevalence of ESBLs-producing K. pneumoniae isolates in the studied population, it seems that screening of

  10. Detection of OXA-type carbapenemases and integrons among carbapenem-resistant Acinetobactor baumannii in a teaching hospital in China.

    PubMed

    Hu, Qiaojuan; Hu, Zhidong; Li, Jing; Tian, Bin; Xu, Hairu; Li, Jin

    2011-10-01

    The increasing trend of carbapenem-resistance (CR) and multi-drug resistance (MDR) in A. baumannii worldwide has limited the therapeutic effectiveness of antibiotic therapy. The study was conducted to determine the prevalence of carbapenemases and integrons among the isolates of imipenem-resistant A. baumannii (IRAB). A total of 71 non-repetitive imipenem- resistant A. baumannii isolates were collected and tested for susceptibility to 17 antimicrobials. The modified Hodge test and EDTA-disc synergy test were performed for the screening of carbapenemases and metallo-β -lactamases (MBLs) production, respectively. Isolates were then subjected to multiplex-PCR targeting genes encoding for OXA-type carbapenemase, MBLs and integrases. Random amplified polymorphic DNA (RAPD) genotyping was performed to assess genetic relatedness. All isolates exhibited multi-drug resistant phenotype. Colistin was the most active antimicrobial agent tested. Seventy-one isolates (100%) demonstrated positive in the modified Hodge test. Thirty-nine isolates showed positive in the EDTA-disc synergy test, however, no MBL genes were detected. All strains possessed a bla(OXA-51) -like gene. The co-exis-tence of bla(OXA-51) -like/bla(OXA-23) -like/intI1, bla(OXA-51) -like/bla(OXA-23) -like, bla(OXA-51) -like/bla(OXA-24) -like was detected in 91.6% (n = 65), 5.6% (n = 4), 2.8% (n = 2), respectively. Analysis of the genetic con-text of bla(OXA-23) showed the presence of ISAba1 upstream of bla(OXA-23) . No ISAba1 was detected upstream of bla(OXA-51) . Two different gene cassettes were found in these strains, and a high prevalence of aacA4, aadA1 and catB8 genes was observed. RAPD of 71 isolates showed 7 genotypes. The strains were mainly recovered from patients in intensive care unit, neurosurgery and department of respiratory disease. These findings show that multi-drug resistance in A. baumannii is a common problem. This study also shows a high distribution of bla(OXA-23) -like and intI1 genes in

  11. High β-Lactamase Levels Change the Pharmacodynamics of β-Lactam Antibiotics in Pseudomonas aeruginosa Biofilms

    PubMed Central

    Ciofu, Oana; Yang, Liang; Wu, Hong; Song, Zhijun; Oliver, Antonio; Høiby, Niels

    2013-01-01

    Resistance to β-lactam antibiotics is a frequent problem in Pseudomonas aeruginosa lung infection of cystic fibrosis (CF) patients. This resistance is mainly due to the hyperproduction of chromosomally encoded β-lactamase and biofilm formation. The purpose of this study was to investigate the role of β-lactamase in the pharmacokinetics (PK) and pharmacodynamics (PD) of ceftazidime and imipenem on P. aeruginosa biofilms. P. aeruginosa PAO1 and its corresponding β-lactamase-overproducing mutant, PAΔDDh2Dh3, were used in this study. Biofilms of these two strains in flow chambers, microtiter plates, and on alginate beads were treated with different concentrations of ceftazidime and imipenem. The kinetics of antibiotics on the biofilms was investigated in vitro by time-kill methods. Time-dependent killing of ceftazidime was observed in PAO1 biofilms, but concentration-dependent killing activity of ceftazidime was observed for β-lactamase-overproducing biofilms of P. aeruginosa in all three models. Ceftazidime showed time-dependent killing on planktonic PAO1 and PAΔDDh2Dh3. This difference is probably due to the special distribution and accumulation in the biofilm matrix of β-lactamase, which can hydrolyze the β-lactam antibiotics. The PK/PD indices of the AUC/MBIC and Cmax/MBIC (AUC is the area under concentration-time curve, MBIC is the minimal biofilm-inhibitory concentration, and Cmax is the maximum concentration of drug in serum) are probably the best parameters to describe the effect of ceftazidime in β-lactamase-overproducing P. aeruginosa biofilms. Meanwhile, imipenem showed time-dependent killing on both PAO1 and PAΔDDh2Dh3 biofilms. An inoculum effect of β-lactams was found for both planktonic and biofilm P. aeruginosa cells. The inoculum effect of ceftazidime for the β-lactamase-overproducing mutant PAΔDDh2Dh3 biofilms was more obvious than for PAO1 biofilms, with a requirement of higher antibiotic concentration and a longer period of treatment

  12. [Sensitivity of Pseudomonas chlororaphis to antibiotics and chemical tools of plant protection].

    PubMed

    Shepelevich, V V; Kiprianova, E A; Iaroshenko, L V; Avdeeva, L V

    2012-01-01

    Examination of sensitivity of 10 Pseudomonas chlororaphis strains belonging to different subspecies to 54 antibiotics has shown that all studied representatives of Pchlororaphis subsp. chlororaphis, P. chlororaphis subsp. aureofaciens and Pchlororaphis subsp. aurantiaca were sensitive to aminoglycoside antibiotics and fluoroquinolones derivatives. Only part of studied strains has shown sensitivity to some beta-lactam antibiotics, imipeneme and meropeneme. In contrast to representatives of two other subspecies both strains of P. chlororaphis subsp. chlororaphis proved to be sensitive to chlortetracycline and cefepime that allows to consider this difference as the characteristic useful for differentiation. All studied P. chlororaphis strains were resistant to chemical fungicides (Scor and Svitch) and the insect growth regulators (Match, Lufox, Engio, Actellik). Resistance of bacteria to these herbicides gives evidence that their combined use is possible.

  13. Improving known classes of antibiotics: an optimistic approach for the future.

    PubMed

    Bush, Karen

    2012-10-01

    New antibiotic agents are desperately needed to treat the multidrug-resistant pathogens that continue to emerge at alarming rates. Many of the agents that have entered full clinical development since 1995 have been members of previously accepted classes of antibiotics. Among these are a new aminoglycoside (plazomicin), anti-MRSA cephalosporins (ceftobiprole and ceftaroline), a monocyclic β-lactam (BAL30072), the β-lactamase inhibitor combination of tazobactam with the anti-pseudomonal cephalosporin ceftolozane, β-lactam combinations with new non-β-lactam inhibitors (MK-7655 with imipenem, and avibactam with ceftazidime and ceftaroline), new macrolides (cethromycin and solithromycin), oxazolidinones (tedizolid phosphate and radezolid), and quinolones (delafloxacin, nemonoxacin and JNJ-Q2). Resistance and safety issues have been circumvented by some of these new agents that have well-established mechanisms of action and defined pathways leading toward regulatory approval.

  14. Pasteurella multocida bacterial meningitis caused by contact with pigs

    PubMed Central

    López, C.; Sanchez-Rubio, P.; Betrán, A.; Terré, R.

    2013-01-01

    Pasteurella multocida belongs to the normal flora of the respiratory and digestive tract of many animals. Animal exposure is a considerable risk factor for Pasteurella infection. P. multocida is the most common cause of local infection after an animal bite but is an unusual cause of meningitis. We present a case of bacterial meningitis by P. multocida in a 37-year-old man who worked in a pig farm and was bitten by a pig. The patient had a defect located in the lamina cribosa and this lesion could be the gateway of the infection, although in this case the infection could also be acquired through the pig bite. The bacteria was identified as P. multocida with the biochemical test API 20E (bioMérieux). In agreement with findings in the literature, the strain was susceptible in vitro to penicillin, ampicillin, cefotaxime, ceftriaxone ciprofloxacin, levofloxacin, imipenem and tetracycline. PMID:24294240

  15. Epinecidin-1 Has Immunomodulatory Effects, Facilitating Its Therapeutic Use in a Mouse Model of Pseudomonas aeruginosa Sepsis

    PubMed Central

    Pan, Chieh-Yu; Chen, Jian-Chyi; Sheen, Jenn-Feng; Lin, Tai-Lang

    2014-01-01

    Antimicrobial peptides (AMPs) are garnering attention as possible alternatives to antibiotics. Here, we describe the antimicrobial properties of epinecidin-1 against a multidrug-resistant clinical isolate of P. aeruginosa (P. aeruginosa R) and a P. aeruginosa strain from ATCC (P. aeruginosa ATCC 19660) in vivo. The MICs of epinecidin-1 against P. aeruginosa R and P. aeruginosa ATCC 19660 were determined and compared with those of imipenem. Epinecidin-1 was found to be highly effective at combating peritonitis infection caused by P. aeruginosa R or P. aeruginosa ATCC 19660 in mouse models, without inducing adverse behavioral effects or liver or kidney toxicity. Taken together, our results indicate that epinecidin-1 enhances the rate of survival of mice infected with the bacterial pathogen P. aeruginosa through both antimicrobial and immunomodulatory effects. PMID:24820078

  16. High Prevalence of Carbapenemase-Producing Enterobacteriaceae among Hospitalized Children in Luanda, Angola

    PubMed Central

    Kieffer, Nicolas; Nordmann, Patrice; Aires-de-Sousa, Marta

    2016-01-01

    This study aimed to evaluate the prevalence of carbapenemase-producing Enterobacteriaceae in Luanda, Angola. A total of 157 rectal samples were collected from children visiting a pediatric hospital in Luanda in March 2015. Fifty-seven imipenem-nonsusceptible enterobacterial isolates were recovered, most of which were non-clonally related. The blaOXA-181 (50/57) and blaNDM-1 (7/57) carbapenemase genes were identified. Notably, OXA-181-producing Escherichia coli isolates rarely coproduced extended-spectrum β-lactamases and consequently remained susceptible to broad-spectrum cephalosporins. The blaOXA-181 gene was always located on an IncX3 plasmid, while the blaNDM-1 gene was located on either IncFIA or IncA/C plasmids. The study identified a high prevalence of OXA-181 among hospitalized children in Angola. PMID:27503638

  17. Nosocomial dissemination of plasmids carrying blaTEM-24, blaDHA-1, aac(6')-Ib-cr, and qnrA6 in Providencia spp. strains isolated from a Tunisian hospital.

    PubMed

    Mahrouki, Sihem; Chihi, Hela; Bourouis, Amel; Ayari, Khaoula; Ferjani, Mustapha; Moussa, Mohamed Ben; Belhadj, Omrane

    2015-01-01

    The aim of this study is to report the emergence of IncA/C conjugative plasmids harboring blaTEM-24, blaDHA-1, qnrA6, and aac(6')-Ib-cr genes among Providencia spp. isolates recovered in 2008 in Tunisia. The double-disk synergy test confirmed the phenotype extended-spectrum β-lactamase (ESBL) in 2 Providencia stuartii and 5 Providencia rettgeri. These ESBLs were coresistant to cefoxitin, chloramphenicol, ofloxacin, and sulfonamides but remained susceptible to imipenem. Three β-lactamases TEM-2, TEM-24, and DHA-1 were detected. blaTEM-24, blaDHA-1, aac(6')-Ib-cr, and qnrA6 genes were successfully transferred to Escherichia coli strain HB101, and they were found located on the conjugatifs IncA/C plasmids. Genetic relatedness showed similar and different patterns among P. stuartii and P. rettgeri strains, respectively.

  18. Two copies of blaNDM-1 gene are present in NDM-1 producing Pseudomonas aeruginosa isolates from Serbia.

    PubMed

    Jovčić, Branko; Lepšanović, Zorica; Begović, Jelena; Filipić, Brankica; Kojić, Milan

    2014-03-01

    New Delhi metallo-β-lactamase producing Pseudomonas aeruginosa isolates are of special interest since P. aeruginosa is a major cause of nosocomial infections, the treatment of which could now be jeopardized, especially in developing countries. Six additional NDM-1 positive P. aeruginosa clinical isolates belonging to two different genotypes were shown to be plasmid-free. PFGE-hybridization experiments revealed the chromosomal location of the blaNDM-1 gene. Restriction analysis and hybridization revealed that two copies of the blaNDM-1 gene are present in the genomes of all tested isolates, as in previously characterized P. aeruginosa MMA83. Moreover, it was shown that increasing imipenem concentration did not have the effect on copy number of the blaNDM-1 gene in the genome of P. aeruginosa MMA83.

  19. Surveillance of antimicrobial resistance in Escherichia coli strains isolated from pigs at Spanish slaughterhouses.

    PubMed

    Teshager, T; Herrero, I A; Porrero, M C; Garde, J; Moreno, M A; Domínguez, L

    2000-07-01

    Antimicrobial resistance can make the efficient treatment of bacterial infections in humans and animals more difficult. Antimicrobial use in food animals may be one of the factors contributing to resistance. The Spanish surveillance network VAV has established a baseline of antimicrobial resistance in Escherichia coli strains from healthy pigs. Minimum inhibitory concentration and patterns of resistance to antimicrobials used in animals and humans were determined for 205 faecal strains isolated in a sampling frame of four slaughterhouses in Spain from 220 pigs in 1998. Higher levels of resistance were seen against antimicrobial agents authorised for use in food animals especially tetracycline, sulphonamides, trimethoprim and amoxycillin. All isolates were susceptible to antimicrobials employed mainly in humans such as ceftazidime, cefotaxime, imipenem, aztreonam and amikacin.

  20. In vitro studies of plasmid-mediated penicillinase from Streptococcus faecalis suggest a staphylococcal origin.

    PubMed Central

    Murray, B E; Mederski-Samoraj, B; Foster, S K; Brunton, J L; Harford, P

    1986-01-01

    A strain of Streptococcus faecalis with plasmid-mediated penicillinase production was studied further. Partially purified penicillinase from the S. faecalis strain hydrolyzed penicillin, ampicillin, and ureido-penicillins but not penicillinase-resistant semisynthetic penicillins, cephalosporins, or imipenem; hydrolysis was inhibited by clavulanic acid. Hydrolysis of a given antibiotic correlated with a marked increase in the minimal inhibitory concentration (MIC) of that drug when a high inoculum was used. As with most enterococci, the MICs of cephalosporins and penicillinase-resistant semisynthetic penicillins were too high for clinical usefulness, although these agents did not show an inoculum effect. Based upon hybridization under stringent conditions of plasmid DNA from the S. faecalis strain to cloned penicillinase genes from Staphylococcus aureus, it appears that these resistance determinants are highly homologous and suggests that this enzyme was introduced into streptococci from staphylococci. Images PMID:3080475

  1. Molecular analysis of the carbapenem and metronidazole resistance mechanisms of Bacteroides strains reported in a Europe-wide antibiotic resistance survey.

    PubMed

    Sóki, József; Eitel, Zsuzsa; Urbán, Edit; Nagy, Elisabeth

    2013-02-01

    Here we examine the carbapenem and metronidazole resistance mechanisms of 640 Bacteroides strains reported in the 2008-2009 European antibiotic susceptibility survey. Of the 22 strains with elevated imipenem minimum inhibitory concentrations (≥4 μg/mL), 10 were cfiA-positive and out of these 5 carried activating insertion sequence (IS) elements in the upstream regions of the cfiA genes. However, resistant strains with cfiA genes but with no activating IS elements were found (n=2) as well as a resistant strain with no cfiA gene. In the former the resistance phenotypes by Etest were heterogeneous, whilst in the latter no carbapenemase production was seen; both mechanisms have been rarely observed, examined and characterised. Interestingly, few (n=3) nim-positive strains were found, including one metronidazole-resistant strain harbouring nimE activated by ISBf6, and two susceptible strains harbouring chromosomally located nim genes.

  2. Prevalence and antimicrobial susceptibility of Salmonella spp. in small Indian mongooses (Herpestes auropunctatus) in Grenada, West Indies.

    PubMed

    Miller, Steven; Amadi, Victor; Stone, Diana; Johnson, Roger; Hariharan, Harry; Zieger, Ulrike

    2014-09-01

    Intestinal samples from 156 small Indian mongooses (Herpestes auropunctatus) collected island-wide in Grenada from April 2011 to March 2013 were examined for the presence of Salmonella enterica spp. Nineteen (12%) mongooses were culture-positive for S. enterica spp. of which five serotypes were identified. Salmonella javiana and S. Montevideo were the most commonly isolated serotypes. The other serotypes isolated were S. Rubislaw, S. Panama and S. Arechavaleta. All isolates were susceptible to amoxicillin-clavulanic acid, ampicillin, cefotaxime, ceftazidime, ciprofloxacin, enrofloxacin, gentamicin, nalidixic acid, imipenem and trimethoprim-sulfamethoxazole. One isolate (S. Montevideo) showed resistance to tetracycline and intermediate resistance to streptomycin. The five isolated Salmonella serotypes are potential human pathogens suggesting that the mongoose may play a role in the epidemiology of human salmonellosis in Grenada.

  3. The β-lactamase inhibitor avibactam (NXL104) does not induce ampC β-lactamase in Enterobacter cloacae

    PubMed Central

    Miossec, Christine; Claudon, Monique; Levasseur, Premavathy; Black, Michael T

    2013-01-01

    Induction of ampC β-lactamase expression can often compromise antibiotic treatment and is triggered by several β-lactams (such as cefoxitin and imipenem) and by the β-lactamase inhibitor clavulanic acid. The novel β-lactamase inhibitor avibactam (NXL104) is a potent inhibitor of both class A and class C enzymes. The potential of avibactam for induction of ampC expression in Enterobacter cloacae was investigated by ampC messenger ribonucleic acid quantitation. Cefoxitin and clavulanic acid were confirmed as ampC inducers, whereas avibactam was found to exert no effect on ampC expression. Thus, avibactam is unlikely to diminish the activity of any partner β-lactam antibiotic against AmpC-producing organisms. PMID:24348054

  4. In Vitro Activities of Tigecycline and Eight Other Antimicrobials against Different Nocardia Species Identified by Molecular Methods▿

    PubMed Central

    Cercenado, Emilia; Marín, Mercedes; Sánchez-Martínez, Mónica; Cuevas, Oscar; Martínez-Alarcón, José; Bouza, Emilio

    2007-01-01

    The in vitro activities of tigecycline and other antimicrobials against 51 isolates of Nocardia spp. were evaluated. MIC90s and MIC ranges were as follows: tigecycline, 4 and ≤0.06 to 8 mg/liter, respectively; minocycline, 2 and ≤0.06 to 2 mg/liter, respectively; linezolid, 1 and ≤0.06 to 2 mg/liter, respectively; moxifloxacin, 2 and ≤0.06 to >64 mg/liter, respectively; ertapenem, 32 and ≤0.06->64 mg/liter, respectively; imipenem, 2 and ≤0.06 to >64 mg/liter, respectively; meropenem, 8 and ≤0.06 to >64 mg/liter, respectively; amikacin, 1 and ≤0.06 to 32 mg/liter, respectively; and trimethoprim-sulfamethoxazole, 1/19 and ≤0.5/9.5 to >2/38 mg/liter, respectively. PMID:17194827

  5. New drugs for the treatment of complicated intra-abdominal infections in the era of increasing antimicrobial resistance.

    PubMed

    Syue, Ling-Shan; Chen, Yen-Hsu; Ko, Wen-Chien; Hsueh, Po-Ren

    2016-04-01

    The continuing increase in multidrug-resistant organisms (MDROs) worldwide has created new challenges in treating complicated intra-abdominal infections (cIAIs). A number of novel antimicrobial agents have been developed against resistant pathogens. To target extended-spectrum β-lactamase (ESBL)-producing pathogens, novel β-lactam antibiotics, such as ceftolozane/tazobactam, ceftazidime/avibactam, aztreonam/avibactam, imipenem/relebactam and S-649266, are antimicrobial alternatives for cIAIs. Two new drugs, eravacycline and plazomicin, have activity against Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae, carbapenem-resistant Acinetobacter baumannii and ESBL-producers. New lipoglycopeptides and oxazolidinones provide feasible options against resistant Gram-positive pathogens. These novel antimicrobials may play a role in improving the clinical outcomes of cIAIs caused by MDROs.

  6. [Detection of metallo-beta-lactamase in Pseudomonas aeruginosa isolated from hospitalized patients in Goiânia, State of Goiás].

    PubMed

    Gonçalves, Diana Christina Pereira Santos; Lima, Ana Beatriz Mori; Leão, Lara Stefania Netto de Oliveira; Filho, José Rodrigues do Carmo; Pimenta, Fabiana Cristina; Vieira, José Daniel Gonçalves

    2009-01-01

    Pseudomonas aeruginosa is a bacterium frequently isolated from hospital environments. This study had the aims of evaluating the susceptibility profile of Pseudomonas aeruginosa previously isolated from patients in a hospital in Goiânia (Goiás, Brazil), performing phenotypic screening for metallo-beta-lactamase production and detecting its genes using the polymerase chain reaction technique. Seventy-five 75 Pseudomonas aeruginosa isolates were evaluated between January 2005 and January 2007. Biochemical identification was performed using the API 20E system and an antibiogram was produced using the Kirby-Bauer method. Among the 62 isolates that were resistant to imipenem and ceftazidime, 35 (56.4%) produced metallo-beta-lactamase, while 26 (74.3%) showed the bla(SPM-1) gene. The frequency of Pseudomonas aeruginosa that produces metallo-beta-lactamase suggests that greater control over the dissemination of resistance in hospital environments is needed.

  7. Growth in Acanthamoeba sp. and antibiotic susceptibility of Legionella micdadei isolated from hot spring water samples.

    PubMed

    Furuhata, Katsunori; Ogihara, Kikumi; Okuno, Rumi; Oonaka, Kenji; Fukuyama, Masafumi

    2009-12-01

    As part of an epidemiological study on legionellosis, we attempted to isolate Legionella spp. from hot spring water samples, and were able to isolate Legionella micdadei from 3 (5.5%) of 55 samples. All of these isolates were able to grow within Acanthamoeba sp., suggesting that the isolates will be pathogens. We also confirmed that the K-2 strain from hot spring water grew in guinea pig monocytes. Sensitivity tests using 10 drugs showed that the isolates were most sensitive to imipenem, with the MIC90 of 0.032 microg/ml, were least sensitive to minocycline, with the MIC90 of 4 microg/ml, and were not sensitive to low amounts of other drugs.

  8. Assay Platform for Clinically Relevant Metallo-β-lactamases

    PubMed Central

    2013-01-01

    Metallo-β-lactamases (MBLs) are a growing threat to the use of almost all clinically used β-lactam antibiotics. The identification of broad-spectrum MBL inhibitors is hampered by the lack of a suitable screening platform, consisting of appropriate substrates and a set of clinically relevant MBLs. We report procedures for the preparation of a set of clinically relevant metallo-β-lactamases (i.e., NDM-1 (New Delhi MBL), IMP-1 (Imipenemase), SPM-1 (São Paulo MBL), and VIM-2 (Verona integron-encoded MBL)) and the identification of suitable fluorogenic substrates (umbelliferone-derived cephalosporins). The fluorogenic substrates were compared to chromogenic substrates (CENTA, nitrocefin, and imipenem), showing improved sensitivity and kinetic parameters. The efficiency of the fluorogenic substrates was exemplified by inhibitor screening, identifying 4-chloroisoquinolinols as potential pan MBL inhibitors. PMID:23898798

  9. Nocardia farcinica abscess of the cerebellum in an immunocompetent patient: A case report and review of the literature

    PubMed Central

    Pascual-Gallego, María; Alonso-Lera, Pedro; Arribi, Ana; Barcia, Juan A.; Marco, Javier

    2016-01-01

    Nocardial brain abscesses are uncommon and rarely occur in patients without predisposing factors. They may be mistaken for gliomas or necrotic metastases, and surgical intervention may be required to make the diagnosis. We report the first case of Nocardia farcinica cerebellar abscess in a patient without immunosuppression. He presented to us with headache and instability beginning a week before. Brain magnetic resonance imaging (MRI) revealed a cystic lesion located at the right cerebellar hemisphere, hypointense in T1 and hyperintense in T2, with a fine wall that enhanced after injection of gadolinium. Image tests also showed a cavitated lesion at the upper lobule of the right lung. The patient underwent craniotomy and drainage of the cerebellar abscess. Initial post-operative treatment with linezolid produced a limited response. He was re-operated and vancomycin, imipenem and ciprofloxacin were added with an excellent outcome of the cerebellar and lung lesions. PMID:27695569

  10. Fabrication, characterization and in vitro profile based interaction with eukaryotic and prokaryotic cells of alginate-chitosan-silica biocomposite.

    PubMed

    Balaure, Paul Catalin; Andronescu, Ecaterina; Grumezescu, Alexandru Mihai; Ficai, Anton; Huang, Keng-Shiang; Yang, Chih-Hui; Chifiriuc, Carmen Mariana; Lin, Yung-Sheng

    2013-01-30

    This work is focused on the fabrication of a new drug delivery system based on polyanionic matrix (e.g. sodium alginate), polycationic matrix (e.g. chitosan) and silica network. The FT-IR, SEM, DTA-TG, eukaryotic cell cycle and viability, and in vitro assay of the influence of the biocomposite on the efficacy of antibiotic drugs were investigated. The obtained results demonstrated the biocompatibility and the ability of the fabricated biocomposite to maintain or improve the efficacy of the following antibiotics: piperacillin-tazobactam, cefepime, piperacillin, imipenem, gentamicin, ceftazidime against Pseudomonas aeruginosa ATCC 27853 and cefazolin, cefaclor, cefuroxime, ceftriaxone, cefoxitin, trimethoprim/sulfamethoxazole against Escherichia coli ATCC 25922 reference strains.

  11. [New antibacterial agents on the market and in the pipeline].

    PubMed

    Kern, W V

    2015-11-01

    After some years of stagnation there have been several new successful developments in the field of antibacterial agents. Most of these new developments have been in conventional antibacterial classes. New drugs among the beta-lactam agents are methicillin-resistant Staphylococcus aureus (MRSA) active cephalosporins (ceftaroline and ceftobiprole) and new combinations of beta-lactam with beta-lactamase inhibitors (ceftolozane/tazobactam, ceftazidime/avibactam, imipenem/relebactam and meropenem/RPX7009). New developments can also be observed among oxazolidinones (tedizolid, radezolid, cadazolid and MRX-I), macrolides/ketolides (modithromycin and solithromycin), aminoglycosides (plazomicin), quinolones (nemonoxacin, delafloxacin and avarofloxacin), tetracyclines (omadacycline and eravacycline) as well as among glycopeptides and lipopeptides (oritavancin, telavancin, dalbavancin and surotomycin). New agents in a very early developmental phase are FabI inhibitors, endolysines, peptidomimetics, lipid A inhibitors, methionyl-tRNA synthetase inhibitors and teixobactin.

  12. Resistance to tetracycline and β-lactams and distribution of resistance markers in enteric microorganisms and pseudomonads isolated from the oral cavity.

    PubMed

    Ramos, Marcelle Marie Buso; Gaetti-Jardim, Ellen Cristina; Gaetti-Jardim Junior, Elerson

    2009-01-01

    This study evaluated the occurrence of enteric bacteria and pseudomonads resistant to tetracycline and β-lactams in the oral cavity of patients exhibiting gingivitis (n=89), periodontitis (n=79), periodontally healthy (n=50) and wearing complete dentures (n=41). Microbial identification and presence of resistance markers associated with the production of β-lactamases and tetracycline resistance were performed by using biochemical tests and PCR. Susceptibility tests were carried out in 201 isolates of enteric cocci and rods. Resistance to ampicillin, amoxicillin/clavulanic acid, imipenem, meropenem and tetracycline was detected in 57.4%, 34.6%, 2.4%, 1.9% and 36.5% of the isolates, respectively. β-lactamase production was observed in 41.2% of tested microorganisms, while the most commonly found β-lactamase genetic determinant was gene blaTEM. Tetracycline resistance was disseminated and a wide scope of tet genes were detected in all studied microbial genus.

  13. Clinical epidemiology of the global expansion of Klebsiella pneumoniae carbapenemases

    PubMed Central

    Munoz-Price, L Silvia; Poirel, Laurent; Bonomo, Robert A; Schwaber, Mitchell J; Daikos, George L; Cormican, Martin; Cornaglia, Giuseppe; Garau, Javier; Gniadkowski, Marek; Hayden, Mary K; Kumarasamy, Karthikeyan; Livermore, David M; Maya, Juan J; Nordmann, Patrice; Patel, Jean B; Paterson, David L; Pitout, Johann; Villegas, Maria Virginia; Wang, Hui; Woodford, Neil; Quinn, John P

    2015-01-01

    Klebsiella pneumoniae carbapenemases (KPCs) were originally identified in the USA in 1996. Since then, these versatile β-lactamases have spread internationally among Gram-negative bacteria, especially K pneumoniae, although their precise epidemiology is diverse across countries and regions. The mortality described among patients infected with organisms positive for KPC is high, perhaps as a result of the limited antibiotic options remaining (often colistin, tigecycline, or aminoglycosides). Triple drug combinations using colistin, tigecycline, and imipenem have recently been associated with improved survival among patients with bacteraemia. In this Review, we summarise the epidemiology of KPCs across continents, and discuss issues around detection, present antibiotic options and those in development, treatment outcome and mortality, and infection control. In view of the limitations of present treatments and the paucity of new drugs in the pipeline, infection control must be our primary defence for now. PMID:23969216

  14. Pseudomonas aeruginosa PAO1 resistance to Zinc pyrithione: phenotypic changes suggest the involvement of efflux pumps.

    PubMed

    Abdel Malek, Suzanne M; Al-Adham, Ibrahim S; Matalka, Khalid Z; Collier, Philip J

    2009-08-01

    The aim of this study is to investigate the involvement of an efflux pump in the development of Pseudomonas aeruginosa resistance to zinc pyrithione (ZnPT). In the presence of efflux inhibitor carbonyl cyanide m-chlorophenyl-hydrazone (CCCP), the minimum inhibitory concentration of ZnPT for P. aeruginosa resistant cells is reduced significantly (p < 0.05). In addition, the concentration of ZnPT excluded by the resistant bacteria was reduced significantly (p < 0.01). However, the above reductions did not reach the levels measured for P. aeruginosa PAO1 sensitive strain. Furthermore, such changes in P. aeruginosa resistant cells were correlated with the overexpression of outer membrane proteins, reduced sensitivity toward imipenem (p < 0.01) and increased sensitivity toward sulphatriad and chloramphenicol (p < 0.05). In a continuation to a previous study, we conclude that P. aeruginosa resistance to ZnPT is multifactorial and involves induced efflux systems.

  15. [Outbreak of nosocomial urinary tract infections due to a multidrug resistant Pseudomonas aeruginosa].

    PubMed

    Boutiba-Ben Boubaker, I; Boukadida, J; Triki, O; Hannachi, N; Ben Redjeb, S

    2003-04-01

    An outbreak of a multidrug resistant Pseudomonas aeruginosa including imipenem resistance occurred in the urology intensive care unit at Charles Nicolle Hospital (Tunis). All isolates presented the same antibiotic resistance pattern and were only susceptible to colistin. The epidemic strain was detected in different sites of this unit. Pulsed-field gel electrophoresis after enzymatic restriction using XbaI was performed in order to establish an epidemiologic link between these infections. Genotypic analysis showed two different patterns and the environmental source was identified in both cases. Although the same antibiotype was harbored by all the isolates, two outbreaks occurring in the same period were identified. The strengthening of hygiene measures allowed to stop the outbreak spreading. Since the hospital environment is the major source of Pseudomonas aeruginosa contamination, a continuous surveillance of the patients and the environmental sources is required for the implementation efficient control measures.

  16. [Gonococcal conjunctivitis complicated by perforating corneal abscess in an adult].

    PubMed

    Gambrelle, J; Ponceau, B; Duquesne, N; Crepet, H; Fleury, J; Burillon, C; Grange, J D; Kodjikian, L

    2007-09-01

    We present a case of bilateral purulent conjunctivitis complicated by ocular perforation of the right eye secondary to fulminant corneal melt in a 29-year-old man. He developed urethritis after a sexual contact with a prostitute 3 weeks previously. Microbiological analyses of conjunctival and urinary cultures were positive for Neisseria gonorrhoeae resistant to penicillins, tetracyclines, and fluoroquinolones. Progression was favorable with a 15-day course of high doses of parenterally administered antibiotics associating imipenem and fosfomycin. Keratoplasty was done after 3 months. This observation is a good example of the problems raised by gonococcal conjunctivitis in adults. Extremely rare in developed countries, it remains widely unrecognized by ophthalmologists. It is a sexually transmitted disease usually resulting from autoinoculation from an infected genital site. The risk of marginal purulent corneal melt, which can lead to fulminant perforation, warrants prompt microbiological analysis and early parenteral antibiotic treatment.

  17. Laboratory investigation of hospital outbreak caused by two different multiresistant Acinetobacter calcoaceticus subsp. anitratus strains.

    PubMed Central

    Vila, J; Almela, M; Jimenez de Anta, M T

    1989-01-01

    During a 7-month period, from December 1986 to June 1987, multiresistant strains of Acinetobacter calcoaceticus subsp. anitratus were isolated from 25 patients in a respiratory intensive care unit. The biochemical characteristics defined two groups of strains, group 1 (14 strains) and group 2 (11 strains). Both groups had the same biochemical characteristics, but group 2 strains could assimilate adipate and phenyl acetate. Moreover, of 16 antibiotics tested only netilmicin and imipenem had some inhibitory activity for group 1 strains; group 2 strains were susceptible to mezlocillin, piperacillin, and ticarcillin. Plasmid profiles of the groups were also different. The results of a laboratory investigation (biochemical characteristics, antibiotic susceptibility, and plasmid isolation) identified two different A. calcoaceticus subsp. anitratus strains as the causes of the outbreak. Images PMID:2745682

  18. KPC-PRODUCING Serratia marcescens IN A HOME-CARE PATIENT FROM RECIFE, BRAZIL

    PubMed Central

    MARGATE, Emmily; MAGALHÃES, Vera; FEHLBERG, Lorena Cristina Corrêa; GALES, Ana Cristina; LOPES, Ana Catarina Souza

    2015-01-01

    SUMMARY In this brief communication we describe the occurrence of a KPC-producing Serratia marcescensisolate in a home-care patient from Recife, Brazil. The bla KPC, bla SPM, bla IMP, bla VIM bla OXA, bla CTX-M, bla SHV, bla TEM and bla GES genes were investigated by Polymerase Chain Reaction (PCR) and DNA sequencing. The isolate was positive for bla KPC-2 and bla TEM-1 and was resistant to aztreonam, cefepime, cefotaxime, imipenem, meropenem, gentamicin, ciprofloxacin and cefazidime, and susceptible only to amikacin, tigecycline and gatifloxacin. This is the first report in Brazil of KPC-producing S. marcescens clinical isolate outside of a hospital environment. Caregivers should be alert for the presence of this isolate in the community setting. PMID:26422164

  19. Evaluation of Antibiotic Susceptibility of Gram-Positive Anaerobic Cocci Isolated from Cancer Patients of the N. N. Blokhin Russian Cancer Research Center.

    PubMed

    Shilnikova, Irina I; Dmitrieva, Natalia V

    2015-01-01

    In total, 81 nonduplicate gram-positive anaerobic cocci (GPAC) were involved in this study. The GPAC were isolated from samples collected from cancer patients between 2004 and 2014. Species identification was carried out by matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS). The majority of isolates were identified as Finegoldia magna (47%) and Peptoniphilus harei (28%). The susceptibility of six species of GPAC was determined for eight antibiotics according to E-test methodology. Furthermore, all isolates were susceptible to imipenem, vancomycin, and linezolid. Susceptibility to penicillin G, amoxicillin/clavulanate, metronidazole, ciprofloxacin, and levofloxacin varied for different species. One Finegoldia magna isolate was multidrug-resistant (i.e., parallel resistance to five antimicrobial agents, including metronidazole, was observed). Two Parvimonas micra isolates were highly resistant to metronidazole (MIC 256 μg/mL) but were sensitive to other tested antibiotics.

  20. Evaluation of Antibiotic Susceptibility of Gram-Positive Anaerobic Cocci Isolated from Cancer Patients of the N. N. Blokhin Russian Cancer Research Center

    PubMed Central

    Shilnikova, Irina I.; Dmitrieva, Natalia V.

    2015-01-01

    In total, 81 nonduplicate gram-positive anaerobic cocci (GPAC) were involved in this study. The GPAC were isolated from samples collected from cancer patients between 2004 and 2014. Species identification was carried out by matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS). The majority of isolates were identified as Finegoldia magna (47%) and Peptoniphilus harei (28%). The susceptibility of six species of GPAC was determined for eight antibiotics according to E-test methodology. Furthermore, all isolates were susceptible to imipenem, vancomycin, and linezolid. Susceptibility to penicillin G, amoxicillin/clavulanate, metronidazole, ciprofloxacin, and levofloxacin varied for different species. One Finegoldia magna isolate was multidrug-resistant (i.e., parallel resistance to five antimicrobial agents, including metronidazole, was observed). Two Parvimonas micra isolates were highly resistant to metronidazole (MIC 256 μg/mL) but were sensitive to other tested antibiotics. PMID:26798518

  1. [Patterns of drug resistance in Staphylococcus aureus from human clinical isolates].

    PubMed

    Rojas Hernández, N M; Fernández López, N; Espino Hernández, M H; Fernández Ferrer, M A

    2001-01-01

    Fifty circulating strains of Staphylococcus aureus of clinical origin were characterized by their drug susceptibility to 15 antimicrobials through the method of radial diffusion in Mueller Hinton medium. Also, beta-lactam production was determined by acidimetric and chromogenic methods as well as the presence of methicillin-resistant strains. It was confirmed that 32% of strain was susceptible to tested antimicrobials, the most effective of which were imipenem, norfloxacyn, and amikacyn for 98, 96 and 92% susceptibility respectively. Twenty-seven different drug resistance patterns were found in the studied strains. 22% of the total strains was beta-lactam producers whereas 27% of the latter turned out to be methicilline-resistant.

  2. Detection and spread of oxa-48-producing Klebsiella oxytoca isolates in Istanbul, Turkey.

    PubMed

    Nazik, Hasan; Aydin, Selda; Albayrak, Rüveyda; Bilgi, Esma A; Yildiz, Ismail; Kuvat, Nuray; Kelesoglu, Fatih M; Kelesoglu, Fatih M; Pakaştiçali, Nagehan; Yilmaz, Fadime; Ongen, Betigül

    2014-01-01

    Five OXA-48 producing Klebsiella oxytoca strains isolated in April-July 2010 were analyzed. Antibiotic susceptibility tests were performed using disc diffusion method and VITEK 2 system. Carbapenemase activity was investigated using the Modified Hodge test. Beta-lactamase genes were detected by PCR and blaOXA-48 was sequenced. Genetic relatedness between K. oxytoca isolates was investigated by pulse-field gel electrophoresis (PFGE). Carbapenemase activity was detected in 5 isolates by Modified Hodge test. Although all strains were resistant to ertapenem and imipenem, only one strain was also resistant to meropenem. BlaOXA-48 in 4 isolates harbored 2 or 3 other ESBL types, namely, blaTEM, blaSHV, blaCTX-M, or blaVEB. PFGE revealed 3 different pulso-types among the K. oxytoca isolates. The presence of OXA-48 carbapenemase in other species of clinical isolates should also be considered.

  3. External Bacterial Flora and Antimicrobial Susceptibility Patterns of Staphylococcus spp. and Pseudomonas spp. Isolated from Two Household Cockroaches, Blattella germanica and Blatta orientalis.

    PubMed

    Menasria, Taha; Tine, Samir; Mahcene, Djaouida; Benammar, Leyla; Megri, Rochdi; Boukoucha, Mourad; Debabza, Manel

    2015-04-01

    A study was performed to estimate the prevalence of the external bacterial flora of two domestic cockroaches (Blattella germanica and Blatta orientalis) collected from households in Tebessa (northeast Algeria). Three major bacterial groups were cultured (total aerobic, enterobacteria, and staphylococci) from 14 specimens of cockroaches, and antibiotic susceptibility was tested for both Staphylococcus and Pseudomonas isolates. Culturing showed that the total bacterial load of cockroaches from different households were comparable (P<0.001) and enterobacteria were the predominant colonizers of the insect surface, with a bacterial load of (2.1 × 10⁵ CFU/insect), whereas the staphylococci group was the minority. Twenty-eight bacterial species were isolated, and susceptibility patterns showed that most of the staphylococci isolates were highly susceptible to chloramphenicol, gentamycin, pristinamycin, ofloxacin, clindamycin, and vancomycin; however, Pseudomonas strains exhibited resistance to amoxicillin/clavulanic acid, imipenem, and the second-generation antibiotic cephalosporin cefuroxime.

  4. Mycobacterium fortuitum thoracic empyema: A case report and review of the literature.

    PubMed

    Matsumoto, Takeshi; Otsuka, Kojiro; Tomii, Keisuke

    2015-10-01

    Mycobacterium fortuitum is a rapidly growing nontuberculous mycobacterium. This microorganism is an uncommon etiological agent of lung lesions; among lung lesions caused by M. fortuitum, thoracic empyema is particularly rare. A 61-year-old man who had been treated for chronic hypercapnic respiratory failure with noninvasive ventilation was admitted because of breathing difficulty and was found to have M. fortuitum thoracic empyema. He improved after the administration of amikacin, imipenem/cilastatin, and clarithromycin following sulfamethoxazole/trimethoprim and clarithromycin. This is the first report of M. fortuitum thoracic empyema in a patient without human immunodeficiency virus infection. The thoracic empyema may have developed via a pulmonary fistula in this case. This case highlights the fact that we must be aware of the possibility of M. fortuitum thoracic empyema, especially in patients with M. fortuitum lung infection and treatment with noninvasive ventilation. Multidrug therapy may be effective and important to the resolution of M. fortuitum thoracic empyema.

  5. Prevalence of Pseudomonas aeruginosa in Post-operative Wound Infection in a Referral Hospital in Haryana, India

    PubMed Central

    Ranjan, K Prabhat; Ranjan, Neelima; Bansal, Satish K; Arora, D R

    2010-01-01

    Background: The objective of our study was to determine the prevalence of Pseudomonas aeruginosa in the isolates of postoperative wound and its susceptibility pattern to commonly used antibiotics. Materials and Methods: During a 2-year period, specimens were received as postoperative wound swabs in Microbiology Laboratory, Maharaja Agrasen Medical College, Agroha (Hisar), Haryana, India. Result: Of the 300 bacterial isolates, 89 (29.6%) were P. aeruginosa, followed by Escherichia coli (61, 20.3%), Klebsiella spp. (50, 16.6%), Staphylococcus aureus (43, 14.3%), Proteus spp. (19, 6.3%), Acinetobacter spp. (9, 3.0%), and Citrobacter freundii (2, 0.6%). There was no growth in 27 (9.0%) specimens. Conclusion: P. aeruginosa isolation was higher in male patients and most common in the age group of 21-40 years. The susceptibility pattern showed the organism to be most commonly susceptible to imipenem, followed by meropenem, cefoperazone/sulbactam, ticarcillin/clavulanate, and amikacin. PMID:21346900

  6. Synthesis of Schiff base 24-membered trivalent transition metal derivatives with their anti-inflammation and antimicrobial evaluation

    NASA Astrophysics Data System (ADS)

    Kumar, Gajendra; Devi, Shoma; Kumar, Dharmendra

    2016-03-01

    The paper presents the synthesis of macrocyclic complexes [{M(C52H36N12O4)X}X2] of Cr(III), Mn(III) and Fe(III) with Schiff base ligand (C52H36N12O4) obtained through the condensation of 1,4-dicarbonyl phenyl dihydrazide with 1,2-di(1H-indol-1-yl)ethane-1,2-dione. The newly formed Schiff base and its complexes have been characterized with the help of elemental analysis, condensation measurements, magnetic measurements and their structure configuration have been determined by various spectroscopic (electronic, IR, 1H NMR, 13C NMR, GCMS) techniques. The electronic spectra of the complexes indicate a five coordinate square pyramidal geometry of the center metal ion. These metal complexes and ligand were tested for their anti-inflammation and antimicrobial inhibiting potential and compared with standard drugs Phenyl butazone (anti-inflammation), Imipenem (antibacterial) and Miconazole (antifungal).

  7. [Vancomycin-resistant enterococci in pediatric hematology: don't panic!].

    PubMed

    Barbé, G; Ploton, C; Pondarré, C; Bertrand, Y; Souillet, G; Philippe, N

    1998-06-01

    Do immunocompromised children, carrying vancomycin-resistant enterococci (VRE) need to be treated? For 3 years, 230 children with chemotherapy and/or bone-marrow transplantation (BMT) received amikacin for gut decontamination and rinsed their mouth with solutions including vancomycin or not, according to the duration and severity of neutropenia. Some patients were isolated, others were at home with ambulatory treatment. The first-line antibio-therapy was piperacillin-amikacin-vancomycin in the chemotherapy unit, imipenem-vancomycin in the BMT unit. Once-a-week, the laboratory used to check the efficiency of decontamination procedures and look for emerging resistant bacteria. Four patients were identified as VRE carriers in their gut flora. The fecal carriage was long-lasting in a single patient, for whom attempts of eradication failed. No patient underwent VRE bacteremia. From our experience, it seems reasonable to neglect enterococcal eradication, provided that hygienic measures are strictly applied.

  8. Eight-Year Surveillance of Antimicrobial Resistance among Enterobacter Cloacae Isolated in the First Bethune Hospital

    NASA Astrophysics Data System (ADS)

    Zhou, Qi; Zhang, Man; Wang, Ailin; Xu, Jiancheng; Yuan, Ye

    This study was to investigate the antimicrobial resistance of Enterobacter cloacae isolated in 8 consecutive years in the First Bethune Hospital. Disk diffusion test was used to study the antimicrobial resistance. The data were analyzed by WHONET 5 software according to Clinical and Laboratory Standards Institute (CLSI). Most of 683 strains of Enterobacter cloacae were collected from sputum 410 (60.0%), secretions and pus 105 (15.4%), urine 69 (10.1%) during the past 8 years. No Enterobacter cloacae was resistant to imipenem and meropenem in the First Bethune Hospital. The antimicrobial resistance of Enterobacter cloacae had increased in recent 8 years. The change of the antimicrobial resistance should be investigated in order to direct rational drug usage in the clinic and prevent bacterial strain of drug resistance from b eing transmitted.

  9. [Antimicrobial susceptibility patterns of the Proteeae in Japan, 1989].

    PubMed

    Igari, J; Hayashi, Y; Shitara, S; Shitara, M; Yoshimoto, K; Ohmizu, Y; Umetsu, M; Sasaki, J; Kawana, R; Yoshida, T

    1993-04-01

    We discussed the antimicrobial susceptibilities of Proteeae isolated in Japan, 1989. Eight hundred six clinical isolates were collected from 47 hospitals. These were comprised of 431 strains of Proteus mirabilis, 155 Proteus vulgaris, 154 Morganella morganii, 44 Providencia rettgeri and 22 Providencia stuartii. Antibiotics tested in this study were 2 penicillins, 5 cephems, 1 carbapenem and 2 aminoglycosides. The MIC's were determined using the standard method of the Japan Society of Chemotherapy. Susceptibilities of the above strains to these antibiotics are described below; 1. Latamoxef, ceftizoxime and imipenem had excellent activities with no evident differences among the species of Proteeae. 2. Ampicillin and cefazolin were less active against Indol-positive Proteeae. 3. Piperacillin and cefmetazole were also strongly active drugs against P. mirabilis, P. vulgaris and P. stuartii, and cefotiam against P. mirabilis and P. stuartii. 4. Gentamicin and netilmicin showed excellent activities against M. morganii.

  10. Bacillus cereus fatal bacteremia and apparent association with nosocomial transmission in an intensive care unit.

    PubMed

    Carretto, E; Barbarini, D; Poletti, F; Marzani, F C; Emmi, V; Marone, P

    2000-01-01

    Bacillus cereus has sometimes been implicated in food poisoning and in opportunistic infections of seriously ill patients. This report describes an unusual case of persistent bacteremia and multiple organ failure associated with B. cereus in a patient admitted to our institution for lung cancer. The patient was undergoing treatment with an antimicrobial agent (imipenem) that was shown to be effective against the micro-organism in vitro. No portal of entry for the strain was detected. After treatment with vancomycin, also shown to be effective in vitro, no clinical improvement was noted and the patient died. Molecular studies showed that the same strain caused an episode of pseudobacteremia in another patient admitted to the same ICU room.

  11. [Current status of nosocomial infections in the Lebanese Hospital Center, Beirut].

    PubMed

    Al-Hajje, A; Ezedine, M; Hammoud, H; Awada, S; Rachidi, S; Zein, S; Salameh, P

    2012-05-01

    Nosocomial infections are a significant problem and hospitals need to be aware of their nosocomial infection status. This retrospective study aimed to identify nosocomial bacterial infections in patients admitted to the Lebanese Hospital Center from January 2006 to January 2008 and determine the causative micro-organisms, the antibiotic sensitivity of the micro-organisms and evaluate the hospital treatment. In total 96 patients with nosocomial infection were included. Urinary infections were the commonest nosocomial infections (42%) followed by pulmonary infections (28%). Gram-negative bacteria were responsible for 89% of nosocomial infections and staphylococci for 7%, with Escherichia coli and Pseudomonas aeruginosa being the most common (46% and 26% respectively). The organisms were resistant to multiples antibiotics and 18% of the patients were treated with imipenem, 7% with vancomycin, 42% with third-generation cephalosporins and 24% with amikacin. Hospital hygiene measures and antibiotic prescription policies are required to fight nosocomial infections and reduce antibiotic resistance among organisms.

  12. Role of ser-237 in the substrate specificity of the carbapenem-hydrolyzing class A beta-lactamase Sme-1.

    PubMed

    Sougakoff, W; Naas, T; Nordmann, P; Collatz, E; Jarlier, V

    1999-08-17

    The role of the serine residue found at position 237 in the carbapenemase Sme-1 has been investigated by constructing a mutant in which Ser-237 was replaced by an alanine. The S237A mutant showed a catalytic behavior against penicillins and aztreonam very similar to that of Sme-1. By contrast, S237A was characterized by a reduced catalytic efficiency against cephems, such as cephalothin and cephaloridine. In addition, the weak activity of Sme-1 against the cephamycin cefoxitin was hardly detectable with the mutant enzyme. Finally, the Ser-237-->Ala mutation resulted in a marked decrease in catalytic activity against imipenem, showing that Ser-237 contributes to the carbapenemase activity of the class A beta-lactamase Sme-1.

  13. [Comparative susceptibility of Ochrobactrum anthropi, Agrobacterium tumefaciens, Alcaligenes faecalis, Alcaligenes denitrificans subsp. denitrificans, Alcaligenes denitrificans subsp. xylosidans and Bordetella bronchiseptica against 35 antibiotics including 17 beta-lactams].

    PubMed

    Bizet, C; Bizet, J

    1995-04-01

    Ochrobactrum anthropi, formerly known as "Achromobacter sp." or CDC group Vd has been isolated from water, hospital environment (antiseptic solutions, dialysis fluids ... ). O. anthropi is a Gram negative, motile, strictly aerobic, oxydase positive and non-fermentative bacteria with a strong urease activity. The susceptibility of 13 strains of O. anthropi was determined by agar diffusion method and compared to those of type strains of Agrobacterium tumefaciens, Alcaligenes faecalis, Alcaligenes denitrificans subsp. denitrificans, Alcaligenes denitrificans subsp. xylosoxydans and Bordetella bronchiseptica. The MICs of 20 antimicrobial agents confirmed the distinct phenotype susceptibility of O. anthropi. All the strains of O. anthropi are sensitive to imipenem, amikacin, gentamicin, netilmicin, nalidixic acid, pefloxacin, ciprofloxacin, tetracyclin, colistin, sulphonamides and rifampicin and resistant to ampicillin, amoxycillin + clavulanic acid, ticarcillin, mezlocillin, cefuroxime, cefamandol, cefoxitin, cefotaxime, cefoperazon, ceftazidime, cefsulodin, aztreonam, streptomycin, kanamycin, pipemidic acid, chloramphenicol, erythromicin, pristinamycin, trimethoprim and fosfomycin. O. anthropi is implicated in nosocomial infections. O. anthropi was the species with the greatest resistance to beta-lactamins.

  14. Detection of drug-resistant Klebsiella pneumoniae in Chinese hares (Lepus sinensis).

    PubMed

    Du, Yingchun; Luo, Jing; Wang, Chengmin; Wen, Qingna; Duan, Mingxing; Zhang, Hong; He, Hongxuan

    2014-01-01

    We investigated an outbreak of acute pneumonia among adult Chinese hares (Lepus sinensis) and diarrhea among juvenile hares in Hebei Province, China, in 2012. Diagnosis was based on necropsy examination, microbial characteristics, biochemical identification, and nucleotide sequence analysis. The isolated bacteria from tissue samples of dead hares were identified as Klebsiella pneumoniae ssp. pneumoniae (K. pneumoniae). This K. pneumoniae was resistant to the antimicrobials imipenem, meropenem, penicillin, and vancomycin, but was highly sensitive to cefepime, cotrimoxazole, and enrofloxacin. Klebsiella pneumoniae is an important opportunistic pathogen, which often causes nosocomial infections in immunocompromised patients. However, the emergence of drug-resistant K. pneumoniae in hares indicates the existence of increasing risk of pathogen transmission between humans and wildlife. Given the close association between wildlife, livestock, and humans, it is important to identify epidemiologic factors associated with infection in these hares to minimize the risk of K. pneumoniae transmission.

  15. Multidrug-resistant Gram-negative bacteria: a product of globalization.

    PubMed

    Hawkey, P M

    2015-04-01

    Global trade and mobility of people has increased rapidly over the last 20 years. This has had profound consequences for the evolution and the movement of antibiotic resistance genes. There is increasing exposure of populations all around the world to resistant bacteria arising in the emerging economies. Arguably the most important development of the last two decades in the field of antibiotic resistance is the emergence and spread of extended-spectrum β-lactamases (ESBLs) of the CTX-M group. A consequence of the very high rates of ESBL production among Enterobacteriaceae in Asian countries is that there is a substantial use of carbapenem antibiotics, resulting in the emergence of plasmid-mediated resistance to carbapenems. This article reviews the emergence and spread of multidrug-resistant Gram-negative bacteria, focuses on three particular carbapenemases--imipenem carbapenemases, Klebsiella pneumoniae carbapenemase, and New Delhi metallo-β-lactamase--and highlights the importance of control of antibiotic use.

  16. [Treatment in the event of antibiotic prophylaxis failure in gynecologic surgery. A retrospective study of 20 cases].

    PubMed

    Paparella, P; Zullo, M A; Astorri, A L; Bondì, M; Maglione, A; Oliva, C; Mancuso Bondì, S

    1994-09-01

    A retrospective study was performed of the type of treatment used in 20 patients undergoing gynecological surgery in whom antibiotic prophylaxis with Mezlocillin (2 g i.v.) had failed. Patients were subdivided into three groups: A) Initial therapy with Mezlocillin (8 patients, 2 g/die i.m.) or Cefotetan (2 patients, 2 g/die i.m.) and subsequent addition of Gentamicin (8 patients, 240 mg/die i.m.) or Tobramycin (2 patients, 200 mg/die i.m.) and subsequently Metronidazole (7 patients, 1.5 g/die per os). B) Therapy with Imipenem/Cilastatin (6 patients, 1.5 g/die i.m.). C) Therapy with Imipenem/Cilastatin (4 patients, 1.5 g/die i.m.) after a variety of antibiotics: Cotrimoxazole (Trimethoprim 160 mg/die and sulphamethoxazole 800 mg/die per os), Pefloxacin (800 mg/die per os), Cefotetan (2 g/die i.m.) and Mezlocillin (2 g/die i.m.). Time taken to lower temperature was shorter in Group B (3.5 days) compared to Group A (6.8 days) and Group C (10 days). Postoperative hospital stay was also shorter in Group B (9 days) compared to Group C (16.5 days) and Group A (11.1 days). The immediate administration of an antibiotic active against Gram+ and Gram- germs, aerobes and anaerobes is therefore useful in the event of failure of antibiotic prophylaxis, rather than the use in succession of associations of antibiotics with a limited spectrum.

  17. Antibiotic Resistance Markers in Strain Bp1651 of Burkholderia pseudomallei Identified by Genome Sequence Analysis.

    PubMed

    Bugrysheva, Julia V; Sue, David; Gee, Jay E; Elrod, Mindy G; Hoffmaster, Alex R; Randall, Linnell B; Chirakul, Sunisa; Tuanyok, Apichai; Schweizer, Herbert P; Weigel, Linda M

    2017-04-10

    Burkholderia pseudomallei Bp1651 is resistant to several classes of antibiotics that are usually effective for treatment of melioidosis including β-lactams such as penicillins (amoxicillin/clavulanic acid), cephalosporins (ceftazidime), carbapenems (imipenem and meropenem), as well as tetracyclines and sulfonamides. We sequenced, assembled, and annotated the Bp1651 genome, and analyzed the sequence using comparative genomic analyses with susceptible strains, keyword searches of the annotation, publicly available antimicrobial resistance prediction tools, and published reports. More than 100 genes in the Bp1651 sequence were identified as potentially contributing to antimicrobial resistance. Most notably, we identified three previously uncharacterized point mutations in penA, which codes for a class A β-lactamase and was previously implicated in resistance to β-lactam antibiotics. The mutations result in amino acid changes T147A, D240G, and V261I. When individually introduced into select agent-excluded B. pseudomallei strain Bp82, D240G was found to contribute to ceftazidime resistance, and T147A contributed to amoxicillin/clavulanic acid and imipenem resistance. This study provides the first evidence that mutations in penA may alter susceptibility to carbapenems in B. pseudomallei Another mutation of interest was a point mutation affecting the dihydrofolate reductase gene folA, which likely explains the trimethoprim resistance of this strain. Bp1651 was susceptible to aminoglycosides likely due to a frame shift in the amrB gene, the transporter subunit of the AmrAB-OprA efflux pump. These findings expand the role of penA to include resistance to carbapenems and may assist in development of molecular diagnostics that predict antimicrobial resistance and provide guidance for treatment of melioidosis.

  18. blaVIM-2 Cassette-Containing Novel Integrons in Metallo-β-Lactamase-Producing Pseudomonas aeruginosa and Pseudomonas putida Isolates Disseminated in a Korean Hospital

    PubMed Central

    Lee, Kyungwon; Lim, Jong Back; Yum, Jong Hwa; Yong, Dongeun; Chong, Yunsop; Kim, June Myung; Livermore, David M.

    2002-01-01

    We investigated the phenotypic and genetic properties of metallo-β-lactamase-producing Pseudomonas isolates collected at a tertiary-care hospital in Korea since 1995. The prevalence of imipenem resistance among Pseudomonas aeruginosa isolates reached 16% in 1997, when 9% of the resistant organisms were found to produce VIM-2 β-lactamase, a class B enzyme previously found only in P. aeruginosa isolates from Europe. VIM-2-producing isolates of Pseudomonas putida were also detected. Resistance was transferable from both these species to P. aeruginosa PAO4089Rp by filter mating, although the resistance determinant could not be found on any detectable plasmid. Serotyping showed that many of the VIM-2-producing P. aeruginosa isolates belonged to serotypes O:11 and O:12, and pulsed-field gel electrophoresis of XbaI-digested genomic DNA revealed that many had identical profiles, whereas the P. putida isolates were diverse. Sequencing showed that the blaVIM-2 genes resided as cassettes in class 1 integrons. In contrast to previous VIM-encoding integrons, the integron sequenced from a P. aeruginosa isolate had blaVIM located downstream of a variant of aacA4. blaVIM also lay in a class 1 integron in a representative P. putida strain, but the organization of this integron was different from that sequenced from the P. aeruginosa strain. In conclusion, the metallo-β-lactamase produced by these imipenem-resistant Pseudomonas isolates was VIM-2, and the accumulation of producers reflected clonal dissemination as well as horizontal spread. Strict measures are required in order to control a further spread of resistance. PMID:11897589

  19. High prevalence of extensively drug-resistant and metallo beta-lactamase-producing clinical Acinetobacter baumannii in Iran.

    PubMed

    Maspi, Hossein; Mahmoodzadeh Hosseini, Hamideh; Amin, Mohsen; Imani Fooladi, Abbas Ali

    2016-09-01

    Acinetobacter species particularly Acinetobacter baumannii (A. baumannii) have been widely reported as broad-spectrum antibiotic resistant pathogens. Expression of various types of metallo beta-lactamases (MBL), classified as Ambler class B, has been associated with carbapenem resistance. Here, we attempted to assess the frequency of extensively drug-resistant (XDR) and MBL-producing A. baumannii among clinical isolates. 86 clinical A. baumannii strains were collected from 2014 to 2015 and their susceptibility to meropenem (10 μg), imipenem (10 μg), azteronem (30 μg), pipracillin (100 μg) tazobactam (110 μg), tobramycin (10 μg), fosfomycin (200 μg), rifampicin (5 μg), colistin (10 μg), tigecycline (15 μg), sulbactam/ampicillin (10 μg + 10 μg) and polymixin B (300 U) was evaluated using disk diffusion method. The MBL-producing isolates were screened using combined disc diffusion method. Furthermore, the presence of blaVIM, blaIMP, blaSPM, blaGIM, blaSIM and blaNDM was detected by PCR. 34.9% of isolates were recovered from bronchoalveolar lavage (BAL). 81 (94.2%) and 62 (71.2%) isolates were multidrug resistance (MDR) and XDR, respectively. 44 (51.2%) and 65 (75.6%) isolates were MBL-producing strains with resistance to imipenem and meropenem, respectively. 2 (2.3%), 13 (15.1%), 2 (2.3%), 4 (4.7%) and 2 (2.3%) isolates carried blaVIM, blaIMP, blaSPM, blaGIM and blaSIM genes, respectively. Our data showed that the rate of XDR and MBL A. baumannii is on the rise.

  20. In vitro antimicrobial synergy of colistin with rifampicin and carbapenems against colistin-resistant Acinetobacter baumannii clinical isolates.

    PubMed

    Hong, Duck Jin; Kim, Jung Ok; Lee, Hyukmin; Yoon, Eun-Jeong; Jeong, Seok Hoon; Yong, Dongeun; Lee, Kyungwon

    2016-10-01

    Increased use of colistin in a clinical setting had resulted in the emergence of colistin-resistant (CoR) Acinetobacter baumannii. Combination therapy has been studied as a new approach to treat infections caused by A. baumannii. Here, we investigated the in vitro antimicrobial synergistic activities of several antimicrobial agent combinations against CoR A. baumannii. A total of 41 non-duplicate clinical isolates of CoR A. baumannii from a tertiary care hospital in Korea were prospectively collected from April 2012 to December 2014. As a control group, 41 carbapenem-resistant but colistin-susceptible (CoS) A. baumannii strains were also evaluated. Minimum inhibitory concentrations (MICs) of antimicrobial agents were determined by Etest in triplicate, and in vitro synergy tests were performed by the Etest MIC:MIC ratio method. Synergistic activity was determined as the sum of each antimicrobial agent's fractional inhibitory concentration evaluated (ΣFIC): synergy, ≤0.5; indifference, >0.5-4; and antagonism, >4. Synergistic activities were more frequently observed in the CoR group than the CoS group for combinations of colistin-rifampicin (80.5% vs. 14.6%, P< 0.0001), colistin-meropenem (85.4% vs. 4.9%, P< 0.0001), and colistin-imipenem (46.3% vs. 2.4%, P< 0.0001). Combination with rifampicin or meropenem lowered colistin MICs against CoR A. baumannii clinical isolates to the susceptible range (≤ 2 μg/mL) more frequently (61.0%, 25/41, both) than combination with imipenem (29.3%, 12/41). Clinical trials are needed to prove the in vivo efficacy of those antimicrobial combinations that exhibited significant in vitro antimicrobial synergistic effects against CoR A. baumannii.

  1. Modified Hodge test using Mueller-Hinton agar supplemented with cloxacillin improves screening for carbapenemase-producing clinical isolates of Enterobacteriaceae.

    PubMed

    Takayama, Yoko; Adachi, Yuzuru; Nihonyanagi, Shin; Okamoto, Ryoichi

    2015-07-01

    Increasing numbers of clinical isolates of Enterobacteriaceae that produce carbapenemase are now being detected, with the most common carbapenemase found among Enterobacteriaceae in Japan being IMP-1-type metallo-β-lactamase. Clinical isolates of Enterobacteriaceae harbouring carbapenemases may be resistant to carbapenem antimicrobial agents, despite apparent in vitro susceptibility when tested according to Clinical and Laboratory Standards Institute criteria. We evaluated the prevalence of carbapenemase producers among isolates of Enterobacteriaceae at our hospital and assessed the performance of the modified Hodge test (MHT) for correctly identifying the phenotype. We studied 47 clinical isolates obtained between 2006 and 2010 for which the MIC of imipenem was 2 or 4 μg imipenem ml- 1. Antibacterial susceptibility testing was done for cephalosporins and carbapenems, the MHT was performed with meropenem and detection of the genes encoding IMP-1, VIM-2, KPC-2 and NDM-1-type metallo-β-lactamases was performed by PCR. Twelve isolates showed a positive result in the MHT with meropenem and were classified as carbapenemase producers. Of these 12 isolates, seven carried the gene for IMP-1 type, but not for VIM-2, KPC-2 or NDM-1 types. None of the carbapenemase genes tested were detected in the other five isolates. All five isolates were Enterobacter cloacae showing high resistance to ceftazidime and aztreonam. False-positive results were inhibited when Mueller-Hinton agar supplemented with 200 mg cloxacillin ml- 1 was used for the MHT. Five of 12 MHT-positive isolates were shown to have no carbapenemase genes and these isolates were high AmpC producers. Adding cloxacillin when performing the MHT prevented such false-positive results. The MHT with cloxacillin can overcome most problems related to detection of carbapenemases.

  2. Novel bacteriophage therapy for controlling metallo-beta-lactamase producing Pseudomonas aeruginosa infection in Catfish

    PubMed Central

    2013-01-01

    Background The bacteriophage therapy is an effective antimicrobial approach with potentially important applications in medicine and biotechnology which can be seen as an additional string in the bow. Emerging drug resistant bacteria in aquaculture industry due to unrestricted use of antibiotics warrants more sustainable and environmental friendly strategies for controlling fish infections. The isolated bacteria from fish lesions was characterised based on isolation on selective and differential medium like Pseudomonas agar, gram staining, biochemical tests and 16SrRNA sequencing. The metallo-beta-lactamase (MBL) producing bacterial isolate was evaluated using Imipenem - Ethylenediaminetetraacetic acid (EDTA) disk method. The specific bacteriophage was isolated and concentrated using coal bed developed in our lab at CSIR-NEERI. The isolated and enriched bacteriophage was characterised by nucleotide sequencing and electron microscopy. The phage therapy was applied for treating ulcerative lesion in fish. Results The pathogenic bacterium responsible for causing ulcerative lesions in catfish species (Clarias gariepinus) was identified as Pseudomonas aeruginosa. One out of twenty P. aeruginosa isolate showing multi drug resistance (MDR) was incidentally found to be MBL producing as determined by Imipenem-EDTA disk method. The phage therapy effectively cured the ulcerative lesions of the infected fish in 8–10 days of treatment, with a sevenfold reduction of the lesion with untreated infection control. Conclusion Bacteriophage therapy can have potential applications soon as an alternative or as a complement to antibiotic treatment in the aquaculture. We present bacteriophage therapy as a treatment method for controlling MDR P. aeruginosa infection in C. gariepinus. To the best of our knowledge this is a first report of application of phage therapy against MBL producing P. aeruginosa isolated from aquatic ecosystem. PMID:24369750

  3. Prevalence and molecular characterisation of New Delhi metallo-β-lactamases NDM-1, NDM-5, NDM-6 and NDM-7 in multidrug-resistant Enterobacteriaceae from India.

    PubMed

    Rahman, Mohibur; Shukla, Sanket Kumar; Prasad, Kashi Nath; Ovejero, Cristina M; Pati, Binod Kumar; Tripathi, Aparna; Singh, Avinash; Srivastava, Ashwini K; Gonzalez-Zorn, Bruno

    2014-07-01

    The growing prevalence of carbapenem resistance in Enterobacteriaceae worldwide is a major concern. New Delhi metallo-β-lactamase (NDM)-mediated carbapenem resistance has been identified in Enterobacteriaceae from numerous countries including those of the Indian subcontinent. Currently, seven NDM β-lactamase variants (NDM-1 to -7) have been identified. This study evaluated the detection and molecular characterisation of NDM variants in Enterobacteriaceae at a tertiary care hospital in India. A total of 464 isolates were tested; 57 (12.3%) were resistant or showed reduced susceptibility to imipenem and meropenem. All carbapenem-resistant isolates were blaNDM-positive by PCR, but 13 isolates bore variants that differed in sequence from blaNDM-1. NDM-5, NDM-6 and NDM-7 were identified in two, eight and three isolates, respectively. blaNDM variants were located on plasmids of >100kb with IncF, IncA/C and untypeable replicon types. Genes encoding the 16S rRNA methyltransferases RmtB, RmtC and ArmA as well as those for AmpC β-lactamases were also located on the same plasmids as blaNDM in different combinations. The prevalence of NDM-5 to -7 variants was significantly higher in Escherichia coli (P=0.015) and they were more frequently isolated from the urology ward (P=0.037) than NDM-1. The mortality rate was comparable between patients infected with isolates positive for blaNDM-1 and blaNDM variants [25% (11/44) vs. 23% (3/13)]. Expression of blaNDM variants in E. coli using the same promoter showed that NDM-7 conferred higher resistance to imipenem. The diverse genotypic features of blaNDM indicate rapid evolution of NDM resulting from their wide spread in the Indian subcontinent.

  4. Porin alterations present in non-carbapenemase-producing Enterobacteriaceae with high and intermediate levels of carbapenem resistance in Chile.

    PubMed

    Wozniak, Aniela; Villagra, Nicolás A; Undabarrena, Agustina; Gallardo, Natalia; Keller, Nicole; Moraga, Marcela; Román, Juan C; Mora, Guido C; García, Patricia

    2012-09-01

    The main goal of this work was to identify the mechanisms responsible for carbapenem resistance in 61 Chilean clinical isolates of Enterobacteriaceae (Enterobacter spp., Serratia marcescens, Morganella morganii, Escherichia coli and Klebsiella pneumoniae) with reduced susceptibility to at least one carbapenem (ertapenem, imipenem or meropenem). All of the isolates were analysed for the presence of carbapenemases, extended spectrum β-lactamases (ESBLs), AmpC enzymes and outer-membrane proteins. None of the isolates exhibited carbapenemase activity nor did they have any of the carbapenemase genes that were screened for. Most of the 61 strains produced at least one ESBL and/or one AmpC enzyme and either lost their porins or had altered porins according to sequence analysis. The distribution of ESBLs and AmpC enzymes was different among the species studied. Resistance in K. pneumoniae and E. coli isolates was associated with ESBLs; in M. morganii isolates, resistance was attributed to overexpression of an AmpC enzyme; and in Enterobacter spp. isolates, resistance was associated with both types of enzymes. In K. pneumoniae isolates, porin integrity was more a determinant of carbapenem resistance than the presence of ESBLs, whereas in isolates of Enterobacter spp., M. morganii and S. marcescens, the presence of an overexpressed AmpC enzyme was associated with higher imipenem and meropenem MIC values. Therefore, carbapenem resistance in Chilean isolates is not due to true carbapenemases but rather to a combination of porin loss/alteration and β-lactamase activity. The fact that carbapenemases were not detected in this study is unique, given that many countries in the region have already reported the presence of these enzymes.

  5. Profile of Virulence Factors in the Multi-Drug Resistant Pseudomonas aeruginosa Strains of Human Urinary Tract Infections (UTI)

    PubMed Central

    Habibi, Asghar; Honarmand, Ramin

    2015-01-01

    Background: Putative virulence factors are responsible for the pathogenicity of UTIs caused by Pseudomonas aeruginosa (P. aeruginosa). Resistance of P. aeruginosa to commonly used antibiotics is caused by the extreme overprescription of those antibiotics. Objectives: The goal of the present study was to investigate the prevalence of virulence factors and the antibiotic resistance patterns of P. aeruginosa isolates in UTI cases in Iran. Patients and Methods: Two hundred and fifty urine samples were collected from patients who suffered from UTIs. Samples were cultured immediately, and those that were P. aeruginosa-positive were analyzed for the presence of virulence genes using polymerase chain reaction (PCR) testing. Antimicrobial susceptibility testing (AST) was performed using the disk diffusion method. Results: Of the 250 urine samples analyzed, 8 samples (3.2%) were positive for P. aeruginosa. The prevalence of P. aeruginosa in male and female patients was 2.7% and 3.5%, respectively, (P = 0.035). In patients less than 10 years old, it was 4.2%, and in patients more than 55 years old, it was 4.2%. These were the most commonly infected groups. The highest levels of resistance were seen against ampicillin (87.5%), norfloxacin (62.5%), gentamycin (62.5%), amikacin (62.5%), and aztreonam (62.5%), while the lowest were seen for meropenem (0%), imipenem (12.5%), and polymyxin B (12.5%). LasB (87.5%), pclH (75%), pilB (75%), and exoS (75%) were the most commonly detected virulence factors in the P. aeruginosa isolates. Conclusions: It is logical to first prescribe meropenem, imipenem, and polymyxin B in cases of UTIs caused by P. aeruginosa. Medical practitioners should be aware of the presence of levels of antibiotic resistance in hospitalized UTI patients in Iran. PMID:26756017

  6. Emergence of Carbapenem resistant Gram negative and vancomycin resistant Gram positive organisms in bacteremic isolates of febrile neutropenic patients: A descriptive study

    PubMed Central

    Irfan, Seema; Idrees, Faiza; Mehraj, Vikram; Habib, Faizah; Adil, Salman; Hasan, Rumina

    2008-01-01

    Background This study was conducted to evaluate drug resistance amongst bacteremic isolates of febrile neutropenic patients with particular emphasis on emergence of carbapenem resistant Gram negative bacteria and vancomycin resistant Enterococcus species. Methods A descriptive study was performed by reviewing the blood culture reports from febrile neutropenic patients during the two study periods i.e., 1999–00 and 2001–06. Blood cultures were performed using BACTEC 9240 automated system. Isolates were identified and antibiotic sensitivities were done using standard microbiological procedures. Results Seven twenty six febrile neutropenic patients were admitted during the study period. A total of 5840 blood cultures were received, off these 1048 (18%) were culture positive. Amongst these, 557 (53%) grew Gram positive bacteria, 442 (42%) grew Gram negative bacteria, 43 (4%) fungi and 6 (1%) anaerobes. Sixty (5.7%) out of 1048 positive blood cultures were polymicrobial. In the Gram negative bacteria, Enterobacteriaceae was the predominant group; E. coli was the most frequently isolated organism in both study periods. Amongst non- Enterobacteriaceae group, Pseudomonas aeruginosa was the commonest organism isolated during first study period followed by Acinetobacter spp. However, during the second period Acinetobacter species was the most frequent pathogen. Enterobacteriaceae group showed higher statistically significant resistance in the second study period against ceftriaxone, quinolone and piperacillin/tazobactam, whilst no resistance observed against imipenem/meropenem. The susceptibility pattern of Acinetobacter species shifted from sensitive to highly resistant one with significant p values against ceftriaxone, quinolone, piperacillin/tazobactam and imipenem/meropenem. Amongst Gram positive bacteria, MRSA isolation rate remained static, vancomycin resistant Enterococcus species emerged in second study period while no Staphylococcus species resistant to

  7. Effect of various antibiotics on modulation of intestinal microbiota and bile acid profile in mice

    SciTech Connect

    Zhang, Youcai; Limaye, Pallavi B.; Renaud, Helen J.; Klaassen, Curtis D.

    2014-06-01

    Antibiotic treatments have been used to modulate intestinal bacteria and investigate the role of intestinal bacteria on bile acid (BA) homeostasis. However, knowledge on which intestinal bacteria and bile acids are modified by antibiotics is limited. In the present study, mice were administered various antibiotics, 47 of the most abundant bacterial species in intestine, as well as individual BAs in plasma, liver, and intestine were quantified. Compared to the two antibiotic combinations (vancomycin + imipenem and cephalothin + neomycin), the three single antibiotics (metronidazole, ciprofloxacin and aztreonam) have less effect on intestinal bacterial profiles, and thus on host BA profiles and mRNA expression of genes that are important for BA homeostasis. The two antibiotic combinations decreased the ratio of Firmicutes to Bacteroidetes in intestine, as well as most secondary BAs in serum, liver and intestine. Additionally, the two antibiotic combinations significantly increased mRNA of the hepatic BA uptake transporters (Ntcp and Oatp1b2) and canalicular BA efflux transporters (Bsep and Mrp2), but decreased mRNA of the hepatic BA synthetic enzyme Cyp8b1, suggesting an elevated enterohepatic circulation of BAs. Interestingly, the two antibiotic combinations tended to have opposite effect on the mRNAs of most intestinal genes, which tended to be inhibited by vancomycin + imipenem but stimulated by cephalothin + neomycin. To conclude, the present study clearly shows that various antibiotics have distinct effects on modulating intestinal bacteria and host BA metabolism. - Highlights: • Various antibiotics have different effects on intestinal bacteria. • Antibiotics alter bile acid composition in mouse liver and intestine. • Antibiotics influence genes involved in bile acid homeostasis. • Clostridia appear to be important for secondary bile acid formation.

  8. Efflux pumps expression and its association with porin down-regulation and β-lactamase production among Pseudomonas aeruginosa causing bloodstream infections in Brazil

    PubMed Central

    2010-01-01

    Background Multi-drug efflux pumps have been increasingly recognized as a major component of resistance in P. aeruginosa. We have investigated the expression level of efflux systems among clinical isolates of P. aeruginosa, regardless of their antimicrobial susceptibility profile. Results Aztreonam exhibited the highest in vitro activity against the P. aeruginosa isolates studied (64.4% susceptibility), whereas susceptibility rates of imipenem and meropenem were both 47.5%. The MexXY-OprM and MexAB-OprM efflux systems were overexpressed in 50.8% and 27.1% of isolates studied, respectively. Overexpression of the MexEF-OprN and MexCD-OprJ systems was not observed. AmpC β-lactamase was overexpressed in 11.9% of P. aeruginosa isolates. In addition, decreased oprD expression was also observed in 69.5% of the whole collection, and in 87.1% of the imipenem non-susceptible P. aeruginosa clinical isolates. The MBL-encoding genes blaSPM-1 and blaIMP-1 were detected in 23.7% and 1.7% P. aeruginosa isolates, respectively. The blaGES-1 was detected in 5.1% of the isolates, while blaGES-5 and blaCTX-M-2 were observed in 1.7% of the isolates evaluated. In the present study, we have observed that efflux systems represent an adjuvant mechanism for antimicrobial resistance. Conclusions Efflux systems in association of distinct mechanisms such as the porin down-regulation, AmpC overproduction and secondary β-lactamases play also an important role in the multi-drug resistance phenotype among P. aeruginosa clinical isolates. PMID:20704733

  9. Aerobic microbiology and culture sensitivity of head and neck space infection of odontogenic origin

    PubMed Central

    Shah, Amit; Ramola, Vikas; Nautiyal, Vijay

    2016-01-01

    Context: Head and neck space infections source, age, gender, tooth involved, fascial spaces involved, microbiological study of aerobic flora, and antibiotic susceptibilities. Aims: The aim of the present study is to identify causative aerobic microorganisms responsible for deep fascial spaces of head and neck infections and evaluate the resistance of antibiotics used in the treatment of such. Settings and Design: Prospective study in 100 patients. Materials and Methods: This prospective study was conducted on 100 patients who reported in the outpatient department and fulfilled the inclusion criteria to study aerobic microbiology and antibiotic sensitivity in head and neck space infection of odontogenic origin. Pus sample was obtained either by aspiration or by swab stick from the involved spaces, and culture and sensitivity tests were performed. Statistical Analysis Used: Chi-square test and level of significance. Results: Result showed aerobic Gram-positive isolates were 73% and aerobic Gram-negative isolates were 18%. Nine percent cases showed no growth. Streptococcus viridans was the highest isolate in 47% cases among Gram-positive bacteria, and in Gram-negative, Klebsiella pneumoniae was the highest isolate of total cases 11%. Amoxicillin showed resistance (48.4%) as compared to other antibiotics such as ceftriaxone, carbenicillin, amikacin, and imipenem had significantly higher sensitivity. Conclusions: Amoxicillin with clavulanic acid showed (64.8%) efficacy for all organisms isolated, whereas ceftriaxone showed (82.4%) efficacy and could be used in odontogenic infections for both Gram-positive and Gram-negative microorganisms. Substitution of third generation cephalosporin for amoxicillin in the empirical management of deep fascial space infections can also be used. Carbenicillin, amikacin, and imipenem showed (93.4%) sensitivity against all microorganisms and should be reserved for more severe infection. Newer and broad-spectrum antibiotics are more

  10. Comparative Stability Studies of Antipseudomonal β-Lactams for Potential Administration through Portable Elastomeric Pumps (Home Therapy for Cystic Fibrosis Patients) and Motor-Operated Syringes (Intensive Care Units)

    PubMed Central

    Viaene, Eric; Chanteux, Hugues; Servais, Hélène; Mingeot-Leclercq, Marie-Paule; Tulkens, Paul M.

    2002-01-01

    The stability of antipseudomonal β-lactams in concentrated solutions was examined in view of their potential administration by continuous infusion with external pumps (for intensive care patients) or with portable pumps carried under clothing (for cystic fibrosis patients). Aztreonam (100 g/liter), piperacillin (128 g/liter, with tazobactam), and azlocillin (128 g/liter) remained 90% stable for up to more than 24 h at 37°C (mezlocillin [128 g/liter] was stable at 25°C but not at 37°C). Ceftazidime (120 g/liter), cefpirome (32 g/liter), and cefepime (50 g/liter) remained 90% stable for up to 24, 23.7, and 20.5 h at 25°C but only for 8, 7.25, and 13 h at 37°C, respectively. The control of temperature therefore appears to be critical for all three cephalosporins that cannot be recommended for use in portable pumps carried under clothes for prolonged periods for reasons of stability. Cefpirome and cefepime solutions developed an important color change (from light yellow to dark red) upon exposure when stored at 30°C or higher. Degradation of ceftazidime was accompanied by the liberation of pyridine which, at 37°C, was in excess of what is allowed by the U.S. Pharmacopeia, i.e., 1.1 mg/liter, after 8 and 12 h for drug concentrations of 12 and 8.3%, respectively. Imipenem and meropenem are too unstable (10% degradation at 25°C after 3.5 and 5.15 h, respectively) to be recommended for use by continuous infusion. Faropenem, examined in comparison with imipenem and meropenem, proved as stable as aztreonam or piperacillin. PMID:12121900

  11. Species distribution and antimicrobial susceptibility of gram-negative aerobic bacteria in hospitalized cancer patients

    PubMed Central

    Ashour, Hossam M; El-Sharif, Amany

    2009-01-01

    Background Nosocomial infections pose significant threats to hospitalized patients, especially the immunocompromised ones, such as cancer patients. Methods This study examined the microbial spectrum of gram-negative bacteria in various infection sites in patients with leukemia and solid tumors. The antimicrobial resistance patterns of the isolated bacteria were studied. Results The most frequently isolated gram-negative bacteria were Klebsiella pneumonia (31.2%) followed by Escherichia coli (22.2%). We report the isolation and identification of a number of less-frequent gram negative bacteria (Chromobacterium violacum, Burkholderia cepacia, Kluyvera ascorbata, Stenotrophomonas maltophilia, Yersinia pseudotuberculosis, and Salmonella arizona). Most of the gram-negative isolates from Respiratory Tract Infections (RTI), Gastro-intestinal Tract Infections (GITI), Urinary Tract Infections (UTI), and Bloodstream Infections (BSI) were obtained from leukemic patients. All gram-negative isolates from Skin Infections (SI) were obtained from solid-tumor patients. In both leukemic and solid-tumor patients, gram-negative bacteria causing UTI were mainly Escherichia coli and Klebsiella pneumoniae, while gram-negative bacteria causing RTI were mainly Klebsiella pneumoniae. Escherichia coli was the main gram-negative pathogen causing BSI in solid-tumor patients and GITI in leukemic patients. Isolates of Escherichia coli, Klebsiella, Enterobacter, Pseudomonas, and Acinetobacter species were resistant to most antibiotics tested. There was significant imipenem -resistance in Acinetobacter (40.9%), Pseudomonas (40%), and Enterobacter (22.2%) species, and noticeable imipinem-resistance in Klebsiella (13.9%) and Escherichia coli (8%). Conclusion This is the first study to report the evolution of imipenem-resistant gram-negative strains in Egypt. Mortality rates were higher in cancer patients with nosocomial Pseudomonas infections than any other bacterial infections. Policies restricting

  12. Correlation between clinical data and antibiotic resistance in coagulase-negative Staphylococcus species isolated from 68 patients with acute post-cataract endophthalmitis.

    PubMed

    Chiquet, C; Maurin, M; Altayrac, J; Aptel, F; Boisset, S; Vandenesch, F; Cornut, P L; Romanet, J P; Gain, P; Carricajo, A

    2015-06-01

    Coagulase-negative staphylococci (CNS) cause the majority of post-cataract endophthalmitis, which can lead to anatomical and/or functional loss of the eye. This study reports the antibiotic susceptibilities of CNS isolates associated with acute post-cataract endophthalmitis cases and correlates antibiotic resistance with severity and outcome of infection in these patients. Clinical data (initial ocular examination, final prognosis, antibiotic treatment) and the antibiotic susceptibilities of the isolated CNS strains were obtained from 68 patients with post-surgical endophthalmitis recruited during a 7-year period by the FRench Institutional ENDophthalmitis Study (FRIENDS) group. The CNS strains displayed 100% susceptibility to vancomycin, 70% to fluoroquinolones, 83% to fosfomycin, 46% to imipenem and 18% to piperacillin. The most effective antibiotic combinations were fosfomycin plus a fluoroquinolone and imipenem plus a fluoroquinolone, which were considered adequate in 80% and 58% of patients, respectively. Methicillin resistance was significantly associated with older age (p 0.001), diabetes mellitus (p 0.004), absence of fundus visibility (p 0.06), and poor visual prognosis (p 0.03). Resistance to fluoroquinolones was significantly associated with absence of fundus visibility (p 0.05) and diabetes mellitus (p 0.02). This large prospective study demonstrates that methicillin resistance and, to a lesser extent, fluoroquinolone resistance in CNS strains causing postoperative endophthalmitis are both prevalent in France and associated with a poorer visual prognosis. These results emphasize the need for an effective surveillance of this antibiotic resistance and the development of new diagnostic tools for rapid detection for early optimization of antibiotic therapy in endophthalmitis patients.

  13. Carbapenem Susceptibility and Multidrug-Resistance in Pseudomonas aeruginosa Isolates in Egypt

    PubMed Central

    Hashem, Hany; Hanora, Amro; Abdalla, Salah; Shawky, Alaa; Saad, Alaa

    2016-01-01

    Background Resistant Pseudomonas aeruginosa is a serious concern for antimicrobial therapy, as the common isolates exhibit variable grades of resistance, involving beta-lactamase enzymes, beside native defense mechanisms. Objectives The present study was designed to determine the occurrence of Metallo-β- Lactamases (MBL) and Amp C harboring P. aeruginosa isolates from Suez Canal university hospital in Ismailia, Egypt. Methods A total of 147 P. aeruginosa isolates, recovered from 311 patients during a 10-month period, were collected between May 2013 and February 2014; the isolates were collected from urine, wound and sputum. Minimum inhibitory concentration (MIC) determined by agar dilution methods was ≥2 μg/mL for meropenem and imipenem. Identification of P. aeruginosa was confirmed using API 20NE. Metallo-β- Lactamases and Amp C were detected based on different phenotypic methods. Results Overall, 26.5% of P. aeruginosa isolates (39/147) were carbapenem resistant isolates. Furthermore, 64.1% (25/39) were MBL producers, these isolates were screened by the combined disc and disc diffusion methods to determine the ability of MBL production. Both MBL and Amp C harbored P. aeruginosa isolates were 28% (7/25). Sixty-four percent of P. aeruginosa isolates were multidrug resistant (MDR) (16/25). The sensitivity toward polymyxin, imipenem, norfloxacin, piperacillin-tazobactam and gentamicin was 99%, 91%, 88%, 82% and 78%, respectively. The resistance rate towards cefotaxime, ceftazidime, cefepime, aztreonam and meropenem was 98.6%, 86%, 71.4%, 34% and 30%, respectively. Conclusions Multidrug resistance was significantly associated with MBL production in P. aeruginosa. Early detection of MBL-producing P. aeruginosa and hospital antibiotic policy prescription helps proper antimicrobial therapy and avoidance of dissemination of these multidrug resistance isolates. PMID:28138370

  14. In vitro activity of tigecycline and comparators against Gram-negative pathogens isolated from blood in Europe (2004-2009).

    PubMed

    Andrasevic, Arjana Tambic; Dowzicky, Michael J

    2012-02-01

    Here we report on the antimicrobial resistance amongst Gram-negative isolates (excluding Acinetobacter spp.) collected from blood culture sources at European study sites as part of the global Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) from the study start in 2004 until August 2009. All isolates were collected and tested for minimum inhibitory concentrations using Clinical and Laboratory Standards Institute methodology. Over the collection period, extended-spectrum β-lactamase (ESBL) production was recorded in 21.1% of Klebsiella pneumoniae, 2.6% of Klebsiella oxytoca and 11.3% of Escherichia coli, primarily in Croatia, Greece, Hungary, Italy, Poland, Romania and the Slovak Republic. ESBL rates stabilised amongst K. pneumoniae over 2006-2009, but doubled amongst E. coli in 2008-2009. The patterns of antimicrobial resistance changed accordingly for both organisms. Generally, Greece had the highest antimicrobial resistance for K. pneumoniae, Italy for E. coli, Serratia marcescens and Enterobacter spp., and Croatia for Pseudomonas aeruginosa. High resistance rates amongst K. pneumoniae were also seen in Croatia and Italy. Imipenem resistance amongst K. pneumoniae was reported exclusively in Greece (13.8%); amongst other Enterobacteriaceae, imipenem resistance was absent or low. Similarly, meropenem resistance was low amongst the Enterobacteriaceae except K. pneumoniae from Greece (42.6%). Across Europe, the most active antimicrobial agents against the Enterobacteriaceae were tigecycline, amikacin and the carbapenems, each with <10% resistance each year. Against the other antimicrobials, significant increases in non-susceptibility were reported for K. pneumoniae and E. coli, both important causative pathogens of bacteraemia.

  15. VEB-1 extended-spectrum β-lactamase-producing multidrug-resistant Proteus mirabilis sepsis outbreak in a neonatal intensive care unit in India: clinical and diagnostic implications

    PubMed Central

    Jain, Sarika; Kothari, Charu; Sehgal, Rachna; Shamweel, A.; Thukral, S. S.; Chellani, Harish K.

    2016-01-01

    Introduction: Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, multidrug-resistant (MDR) pathogens, are increasingly implicated in nosocomial outbreaksworldwide, particularly in neonatal intensive care units (NICUs). Proteus mirabilis is an uncommon nosocomial pathogen causing sepsis in neonates. Case Presentation: We report an outbreak of ESBL-positive MDR P. mirabilis sepsis involving five babies within 10 days in a NICU, which was promptly detected and managed. The aim of this study was to characterize the molecular mechanism of resistance to third-generation cephalosporins (3GCs) in the bacteria. Surveillance cultures were collected from health-care personnel (hand swabs, urine) and the surrounding patient-care environment. Ribotyping was performed to determine the clonality of the strain. Thirteen P. mirabilis were recovered from the blood cultures of the five babies and surveillance cultures. Twelve isolates were positive for the VEB-1 ESBL type, and were susceptible only to ciprofloxacin and carbapenems. There was an unusual phenotypic synergy observed between the 3GCs and imipenem/cefoxitin. The source of infection was traced to a contaminated multidose vial. The outbreak was associated with a high mortality (80 %). A change of empirical antibiotic policy to ciprofloxacin, with strict infection control measures, brought the outbreak to an abrupt end. Conclusion: This is believed to be the first report of a nosocomial outbreak of VEB-1 ESBL-producing P. mirabilis sepsis in neonates from India. The present report of infection due to VEB-1-producing P. mirabilis, an uncommon pathogen for an epidemic in a neonatal unit, highlights the growing significance of such Gram-negative bacteria as a cause of infections in newborns. Epidemic spread in a neonatal unit of an ESBL-producing Proteus species, which also had an intrinsically reduced susceptibility to imipenem, and resistance to colistin and tigecycline, can be a threatening situation and

  16. [Evaluation of phenotypic methods for the detection of KPC carbapenemases in Klebsiella pneumoniae].

    PubMed

    Nicola, Federico G; Nievas, Jimena; Smayevsky, Jorgelina

    2012-01-01

    We evaluated phenotypic methods for the detection of kPc carbapenemases in 44 clinical isolates of K. pneumoniae having reduced susceptibility to carbapenems, 30 of which were kPc-positive and 14 kPc-negative. Both the agar dilution and disk diffusion methods were performed for imipenem, meropenem and ertapenem. The following phenotypic methods were assayed: the double disk synergy test, using boronic acid or clavulanic acid as inhibitors, "combined" disks of carbapenem plus inhibitor (boronic acid, clavulanic acid and both boronic plus clavulanic acid), by using a pre-diffusion technique and the modified Hodge test. The double disk diffusion test using boronic acid could detect all kPc-positive isolates, but adjustment of disk distance was necessary for achieving such performance. The simulation of combined disks by our pre-diffusion technique detected all kPcpositive strains for all 3 carbapenems when using boronic acid as inhibitor, clavulanic acid was less susceptible and specific as compared with boronic acid. The modified Hodge test using any carbapenem was clearly positive for all kPc-producing isolates. This test was negative for all kPc-negative strains when imipenem or meropenem were used, but 2/14 isolates yielded a weak positive result when using ertapenem. By measuring the enhanced growth of E. coli aTcc 25922 observed in this test, we could objectively discriminate true-positive (= 8 mm) from false-positive results (< 5 mm). Our results show that the use of phenotypic methods is effective for the rapid detection of kPc producers in K. pneumoniae isolates with reduced susceptibility to carbapenems.

  17. Kinetic Features of L,D-Transpeptidase Inactivation Critical for β-Lactam Antibacterial Activity

    PubMed Central

    Lecoq, Lauriane; Bougault, Catherine; Mainardi, Jean-Luc; Rice, Louis B.; Ethève-Quelquejeu, Mélanie; Gutmann, Laurent; Marie, Arul; Dubost, Lionel; Hugonnet, Jean-Emmanuel; Simorre, Jean-Pierre; Arthur, Michel

    2013-01-01

    Active-site serine D,D-transpeptidases belonging to the penicillin-binding protein family (PBPs) have been considered for a long time as essential for peptidoglycan cross-linking in all bacteria. However, bypass of the PBPs by an L,D-transpeptidase (Ldtfm) conveys high-level resistance to β-lactams of the penam class in Enterococcus faecium with a minimal inhibitory concentration (MIC) of ampicillin >2,000 µg/ml. Unexpectedly, Ldtfm does not confer resistance to β-lactams of the carbapenem class (imipenem MIC = 0.5 µg/ml) whereas cephems display residual activity (ceftriaxone MIC = 128 µg/ml). Mass spectrometry, fluorescence kinetics, and NMR chemical shift perturbation experiments were performed to explore the basis for this specificity and identify β-lactam features that are critical for efficient L,D-transpeptidase inactivation. We show that imipenem, ceftriaxone, and ampicillin acylate Ldtfm by formation of a thioester bond between the active-site cysteine and the β-lactam-ring carbonyl. However, slow acylation and slow acylenzyme hydrolysis resulted in partial Ldtfm inactivation by ampicillin and ceftriaxone. For ampicillin, Ldtfm acylation was followed by rupture of the C5–C6 bond of the β-lactam ring and formation of a secondary acylenzyme prone to hydrolysis. The saturable step of the catalytic cycle was the reversible formation of a tetrahedral intermediate (oxyanion) without significant accumulation of a non-covalent complex. In agreement, a derivative of Ldtfm blocked in acylation bound ertapenem (a carbapenem), ceftriaxone, and ampicillin with similar low affinities. Thus, oxyanion and acylenzyme stabilization are both critical for rapid L,D-transpeptidase inactivation and antibacterial activity. These results pave the way for optimization of the β-lactam scaffold for L,D-transpeptidase-inactivation. PMID:23861815

  18. Approach to Carbapenemase Detection in Klebsiella pneumoniae in Routine Diagnostic Laboratories

    PubMed Central

    Shenoy, Shalini; Mala, Suchitra Shenoy; Baliga, Shrikala; Ashish, Agarwal

    2016-01-01

    Introduction Resistance to Carbapenems in Klebsiella may be due to Carbapenem hydrolysing enzymes. Accurate detection of carbapenemase must be done for patient treatment and epidemiological purposes. Aim To detect carbapenemase production by performing Modified Hodge Test (MHT), Combined Disk Test (CDT) for Metallo-β-Lactamases (MBL) and PCR for blaKPC gene, to evaluate the performance of MHT using MacConkey Agar (MCA) and to access the value of MHT for carbapenemase detection. Material and Methods Using a prospective laboratory study design, 153 Extended Spectrum Beta-Lactamases (ESBL) producing Klebsiella pneumoniae from clinical samples of patients admitted in the Kasturba Medical College were collected from January 2014 to December 2015. Isolates resistant to carbapenems by disk diffusion were subjected to MHT on MCA and Mueller Hinton agar (MHA). All isolates were tested for (MBL) production by Imipenem and Imipenem-EDTA CDT and subjected to PCR for the presence of blaKPC gene. Results Out of 153 isolates, 54 were resistant to one of the carbapenems. Among these, 13 were positive for MHT on MHA, while 23 were positive by MHT on MCA. Number of MBL producers was 23 (42.5%), while blaKPC was detected in 2 out of the 54 isolates. Conclusion Though detection of drug resistance gene remains the method of choice, it can be performed only in centers with adequate resources. Hence, for most laboratories in resource poor countries, the MHT performed on MCA with concomitant CDT for MBL detection seem to be a better option for detection of Carbapenem resistance. PMID:28208858

  19. An Inactivated Antibiotic-Exposed Whole-Cell Vaccine Enhances Bactericidal Activities Against Multidrug-Resistant Acinetobacter baumannii

    PubMed Central

    Shu, Meng-Hooi; MatRahim, NorAziyah; NorAmdan, NurAsyura; Pang, Sui-Ping; Hashim, Sharina H.; Phoon, Wai-Hong; AbuBakar, Sazaly

    2016-01-01

    Vaccination may be an alternative treatment for infection with multidrug-resistance (MDR) Acinetobacter baumannii. The study reported here evaluated the bactericidal antibody responses following immunization of mice using an inactivated whole-cell vaccine derived from antibiotic-exposed MDR A. baumannii (I-M28-47-114). Mice inoculated with I-M28-47 (non-antibiotic-exposed control) and I-M28-47-114 showed a high IgG antibody response by day 5 post-inoculation. Sera from mice inoculated with I-M28-47-114 collected on day 30 resulted in 80.7 ± 12.0% complement-mediated bacteriolysis in vitro of the test MDR A. baumannii treated with imipenem, which was a higher level of bacteriolysis over sera from mice inoculated with I-M28-47. Macrophage-like U937 cells eliminated 49.3 ± 11.6% of the test MDR A. baumannii treated with imipenem when opsonized with sera from mice inoculated with I-M28-47-114, which was a higher level of elimination than observed for test MDR A. baumannii opsonized with sera from mice inoculated with I-M28-47. These results suggest that vaccination with I-M28-47-114 stimulated antibody responses capable of mounting high bactericidal killing of MDR A. baumannii. Therefore, the inactivated antibiotic-exposed whole-cell vaccine (I-M28-47-114) has potential for development as a candidate vaccine for broad clearance and protection against MDR A. baumannii infections. PMID:26923424

  20. Characterization of a Carbapenem-Hydrolyzing Enzyme, PoxB, in Pseudomonas aeruginosa PAO1

    PubMed Central

    Zincke, Diansy; Balasubramanian, Deepak; Silver, Lynn L.

    2015-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen often associated with severe and life-threatening infections that are highly impervious to treatment. This microbe readily exhibits intrinsic and acquired resistance to varied antimicrobial drugs. Resistance to penicillin-like compounds is commonplace and provided by the chromosomal AmpC β-lactamase. A second, chromosomally encoded β-lactamase, PoxB, has previously been reported in P. aeruginosa. In the present work, the contribution of this class D enzyme was investigated using a series of clean in-frame ampC, poxB, and oprD deletions, as well as complementation by expression under the control of an inducible promoter. While poxB deletions failed to alter β-lactam sensitivities, expression of poxB in ampC-deficient backgrounds decreased susceptibility to both meropenem and doripenem but had no effect on imipenem, penicillin, and cephalosporin MICs. However, when expressed in an ampCpoxB-deficient background, that additionally lacked the outer membrane porin-encoding gene oprD, PoxB significantly increased the imipenem as well as the meropenem and doripenem MICs. Like other class D carbapenem-hydrolyzing β-lactamases, PoxB was only poorly inhibited by class A enzyme inhibitors, but a novel non-β-lactam compound, avibactam, was a slightly better inhibitor of PoxB activity. In vitro susceptibility testing with a clinical concentration of avibactam, however, failed to reduce PoxB activity against the carbapenems. In addition, poxB was found to be cotranscribed with an upstream open reading frame, poxA, which itself was shown to encode a 32-kDa protein of yet unknown function. PMID:26621621

  1. Antimicrobial susceptibility and minimal inhibitory concentration of Pseudomonas aeruginosa isolated from septic ocular surface disease in different animal species

    PubMed Central

    Leigue, L.; Montiani-Ferreira, F.; Moore, B.A.

    2016-01-01

    The purpose of this study was to evaluate the antibiotic susceptibility profile of Pseudomonas aeruginosa isolated from different animal species with septic ocular surface disease. Sixteen strains of P. aeruginosa were isolated from different species of animals (dog, cat, horse, penguin and brown bear) with ocular surface diseases such as conjunctivitis, keratocojnuctivits sicca and ulcerative keratitis. These isolates were tested against 11 different antimicrobials agents using the Kirby-Bauer disk-diffusion method. Minimum inhibitory concentrations (MICs) were determined using E-tests for two antibiotics (tobramycin and ciprofloxacin) commonly used in veterinary ophthalmology practice. Imipenem was the most effective antibiotic, with 100% of the strains being susceptible, followed by amikacin (87.5%), gentamicin, norfloxacin, gatifloxacin and polymyxin (both with 81.5%of susceptibility). MIC90 of ciprofloxacin was 2 µg/ml and the values found ranged from 0.094 µg/ml to 32 µg/ml. For tobramycin, MIC90 was 32 µg/ml and ranged from 0.25 µg/ml to 256 µg/ml. The most effective in vitro antibiotic tested against P. aeruginosa in this study was imipenem, followed by amikacin. The 3 mg/ml eye drops commercially available ciprofloxacin presentations were in vitro effective against all strains tested in this study if applied up to 4 hours after instillation. Whereas for tobramycin the 3 mg/ml eye drops commercial presentations were not in vitro effective against some strains isolated in this study. Thus for ocular infections with P. aeruginosa when using tobramycin the ideal recommendation would be to either use eye drops with higher concentrations or decrease the frequency intervals from four to a minimum of every two hours. PMID:27928519

  2. Genetic-Biochemical Analysis and Distribution of the Ambler Class A β-Lactamase CME-2, Responsible for Extended-Spectrum Cephalosporin Resistance in Chryseobacterium (Flavobacterium) meningosepticum

    PubMed Central

    Bellais, Samuel; Poirel, Laurent; Naas, Thierry; Girlich, Delphine; Nordmann, Patrice

    2000-01-01

    In vitro synergy between extended-spectrum cephalosporins and either clavulanic acid or cefoxitin was found for Chryseobacterium meningosepticum isolates during a double-disk assay on an agar plate. An extended-spectrum β-lactamase (ESBL) gene from a C. meningosepticum clinical isolate was cloned and expressed in Escherichia coli DH10B. Its protein conferred resistance to most β-lactams including extended-spectrum cephalosporins but not to cephamycins or to imipenem. Its activity was strongly inhibited by clavulanic acid, sulbactam, and tazobactam, as well as by cephamycins and imipenem. Sequence analysis of the cloned DNA fragment revealed an open reading frame (ORF) of 891 bp with a G+C content of 33.9%, which lies close to the expected range of G+C contents of members of the Chryseobacterium genus. The ORF encoded a precursor protein of 297 amino acids, giving a mature protein with a molecular mass of 31 kDa and a pI value of 9.2 in E. coli. This gene was very likely chromosomally located. Amino acid sequence comparison showed that this β-lactamase, named CME-2 (C. meningosepticum ESBL), is a novel ESBL of the Ambler class A group (Bush functional group 2be), being weakly related to other class A β-lactamases. It shares only 39 and 35% identities with the ESBLs VEB-1 from E. coli MG-1 and CBL-A from Bacteroides uniformis, respectively. The distribution of blaCME-2 among unrelated C. meningosepticum species isolates showed that blaCME-2-like genes were found in the C. meningosepticum strains studied but were absent from strains of other C. meningosepticum-related species. Each C. meningosepticum strain produced at least two β-lactamases, with one of them being a noninducible serine ESBL with variable pIs ranging from 7.0 to 8.5. PMID:10602714

  3. Insights into β-Lactamases from Burkholderia Species, Two Phylogenetically Related yet Distinct Resistance Determinants*

    PubMed Central

    Papp-Wallace, Krisztina M.; Taracila, Magdalena A.; Gatta, Julian A.; Ohuchi, Nozomi; Bonomo, Robert A.; Nukaga, Michiyoshi

    2013-01-01

    Burkholderia cepacia complex and Burkholderia pseudomallei are opportunistic human pathogens. Resistance to β-lactams among Burkholderia spp. is attributable to expression of β-lactamases (e.g. PenA in B. cepacia complex and PenI in B. pseudomallei). Phylogenetic comparisons reveal that PenA and PenI are highly related. However, the analyses presented here reveal that PenA is an inhibitor-resistant carbapenemase, most similar to KPC-2 (the most clinically significant serine carbapenemase), whereas PenI is an extended spectrum β-lactamase. PenA hydrolyzes β-lactams with kcat values ranging from 0.38 ± 0.04 to 460 ± 46 s−1 and possesses high kcat/kinact values of 2000, 1500, and 75 for β-lactamase inhibitors. PenI demonstrates the highest kcat value for cefotaxime of 9.0 ± 0.9 s−1. Crystal structure determination of PenA and PenI reveals important differences that aid in understanding their contrasting phenotypes. Changes in the positioning of conserved catalytic residues (e.g. Lys-73, Ser-130, and Tyr-105) as well as altered anchoring and decreased occupancy of the deacylation water explain the lower kcat values of PenI. The crystal structure of PenA with imipenem docked into the active site suggests why this carbapenem is hydrolyzed and the important role of Arg-220, which was functionally confirmed by mutagenesis and biochemical characterization. Conversely, the conformation of Tyr-105 hindered docking of imipenem into the active site of PenI. The structural and biochemical analyses of PenA and PenI provide key insights into the hydrolytic mechanisms of β-lactamases, which can lead to the rational design of novel agents against these pathogens. PMID:23658015

  4. Insights into β-lactamases from Burkholderia species, two phylogenetically related yet distinct resistance determinants.

    PubMed

    Papp-Wallace, Krisztina M; Taracila, Magdalena A; Gatta, Julian A; Ohuchi, Nozomi; Bonomo, Robert A; Nukaga, Michiyoshi

    2013-06-28

    Burkholderia cepacia complex and Burkholderia pseudomallei are opportunistic human pathogens. Resistance to β-lactams among Burkholderia spp. is attributable to expression of β-lactamases (e.g. PenA in B. cepacia complex and PenI in B. pseudomallei). Phylogenetic comparisons reveal that PenA and PenI are highly related. However, the analyses presented here reveal that PenA is an inhibitor-resistant carbapenemase, most similar to KPC-2 (the most clinically significant serine carbapenemase), whereas PenI is an extended spectrum β-lactamase. PenA hydrolyzes β-lactams with k(cat) values ranging from 0.38 ± 0.04 to 460 ± 46 s(-1) and possesses high k(cat)/k(inact) values of 2000, 1500, and 75 for β-lactamase inhibitors. PenI demonstrates the highest kcat value for cefotaxime of 9.0 ± 0.9 s(-1). Crystal structure determination of PenA and PenI reveals important differences that aid in understanding their contrasting phenotypes. Changes in the positioning of conserved catalytic residues (e.g. Lys-73, Ser-130, and Tyr-105) as well as altered anchoring and decreased occupancy of the deacylation water explain the lower k(cat) values of PenI. The crystal structure of PenA with imipenem docked into the active site suggests why this carbapenem is hydrolyzed and the important role of Arg-220, which was functionally confirmed by mutagenesis and biochemical characterization. Conversely, the conformation of Tyr-105 hindered docking of imipenem into the active site of PenI. The structural and biochemical analyses of PenA and PenI provide key insights into the hydrolytic mechanisms of β-lactamases, which can lead to the rational design of novel agents against these pathogens.

  5. Pseudomonas aeruginosa Reveals High Intrinsic Resistance to Penem Antibiotics: Penem Resistance Mechanisms and Their Interplay

    PubMed Central

    Okamoto, Kiyomi; Gotoh, Naomasa; Nishino, Takeshi

    2001-01-01

    Pseudomonas aeruginosa exhibits high intrinsic resistance to penem antibiotics such as faropenem, ritipenem, AMA3176, sulopenem, Sch29482, and Sch34343. To investigate the mechanisms contributing to penem resistance, we used the laboratory strain PAO1 to construct a series of isogenic mutants with an impaired multidrug efflux system MexAB-OprM and/or impaired chromosomal AmpC β-lactamase. The outer membrane barrier of PAO1 was partially eliminated by inducing the expression of the plasmid-encoded Escherichia coli major porin OmpF. Susceptibility tests using the mutants and the OmpF expression plasmid showed that MexAB-OprM and the outer membrane barrier, but not AmpC β-lactamase, are the main mechanisms involved in the high intrinsic penem resistance of PAO1. However, reducing the high intrinsic penem resistance of PAO1 to the same level as that of penem-susceptible gram-negative bacteria such as E. coli required the loss of either both MexAB-OprM and AmpC β-lactamase or both MexAB-OprM and the outer membrane barrier. Competition experiments for penicillin-binding proteins (PBPs) revealed that the affinity of PBP 1b and PBP 2 for faropenem were about 1.8- and 1.5-fold lower, than the respective affinity for imipenem. Loss of the outer membrane barrier, MexAB, and AmpC β-lactamase increased the susceptibility of PAO1 to almost all penems tested compared to the susceptibility of the AmpC-deficient PAO1 mutants to imipenem. Thus, it is suggested that the high intrinsic penem resistance of P. aeruginosa is generated from the interplay among the outer membrane barrier, the active efflux system, and AmpC β-lactamase but not from the lower affinity of PBPs for penems. PMID:11408209

  6. Pseudomonas aeruginosa reveals high intrinsic resistance to penem antibiotics: penem resistance mechanisms and their interplay.

    PubMed

    Okamoto, K; Gotoh, N; Nishino, T

    2001-07-01

    Pseudomonas aeruginosa exhibits high intrinsic resistance to penem antibiotics such as faropenem, ritipenem, AMA3176, sulopenem, Sch29482, and Sch34343. To investigate the mechanisms contributing to penem resistance, we used the laboratory strain PAO1 to construct a series of isogenic mutants with an impaired multidrug efflux system MexAB-OprM and/or impaired chromosomal AmpC beta-lactamase. The outer membrane barrier of PAO1 was partially eliminated by inducing the expression of the plasmid-encoded Escherichia coli major porin OmpF. Susceptibility tests using the mutants and the OmpF expression plasmid showed that MexAB-OprM and the outer membrane barrier, but not AmpC beta-lactamase, are the main mechanisms involved in the high intrinsic penem resistance of PAO1. However, reducing the high intrinsic penem resistance of PAO1 to the same level as that of penem-susceptible gram-negative bacteria such as E. coli required the loss of either both MexAB-OprM and AmpC beta-lactamase or both MexAB-OprM and the outer membrane barrier. Competition experiments for penicillin-binding proteins (PBPs) revealed that the affinity of PBP 1b and PBP 2 for faropenem were about 1.8- and 1.5-fold lower, than the respective affinity for imipenem. Loss of the outer membrane barrier, MexAB, and AmpC beta-lactamase increased the susceptibility of PAO1 to almost all penems tested compared to the susceptibility of the AmpC-deficient PAO1 mutants to imipenem. Thus, it is suggested that the high intrinsic penem resistance of P. aeruginosa is generated from the interplay among the outer membrane barrier, the active efflux system, and AmpC beta-lactamase but not from the lower affinity of PBPs for penems.

  7. In vitro susceptibility to antimicrobial agents and ultrastructural characteristics related to swimming motility and drug action in Campylobacter jejuni and C. coli.

    PubMed

    Yabe, Shizuka; Higuchi, Wataru; Takano, Tomomi; Razvina, Olga; Iwao, Yasuhisa; Isobe, Hirokazu; Yamamoto, Tatsuo

    2010-06-01

    Campylobacter jejuni has recently been noted as the most common cause of bacterial food-borne diseases in Japan. In this study, we examined in vitro susceptibility to 36 antimicrobial agents of 109 strains of C. jejuni and C. coli isolated from chickens and patients with enteritis or Guillain-Barré syndrome from 1996 to 2009. Among these agents, carbapenems (imipenem, meropenem, panipenem, and biapenem) showed the greatest activity [minimal inhibitory concentration (MIC)(90), 0.03-0.125 microg/ml]. This was followed by sitafloxacin (MIC(90), 0.25 microg/ml), furazolidone and azithromycin (MIC(90), 0.5 microg/ml), gentamicin and clindamycin (MIC(90), 1 microg/ml), and clavulanic acid (beta-lactamase inhibitor; MIC(90), 2 microg/ml). All or most strains were resistant to aztreonam, sulfamethoxazole, and trimethoprim. Marked resistance was also observed for levofloxacin and tetracyclines. Resistance was not present for macrolides and rare for clindamycin. C. jejuni (and C. coli) exhibited high swimming motility and possessed a unique end-side (cup-like) structure at both ends, in contrast to Helicobacter pylori and Vibrio cholerae O1 and O139. The morphology of C. jejuni (and C. coli) changed drastically after exposure to imipenem (coccoid formation), meropenem (bulking and slight elongation), and sitafloxacin (marked elongation), and exhibited reduced motility. In the HEp-2 cell adherence model, unusually elongated bacteria were also observed for sitafloxacin. The data suggest that although resistance to antimicrobial agents (e.g., levofloxacin) has continuously been noted, carbapenems, sitafloxacin, and others such as beta-lactamase inhibitors alone showed good in vitro activity and that C. jejuni (and C. coli) demonstrated a unique ultrastructural nature related to high swimming motility and drug action.

  8. Occurrence and antimicrobial susceptibility of enteric rods and pseudomonads isolated from the dental prostheses biofilm

    PubMed Central

    Silva, Sanrrangers Sales; Ribeiro, Maximilo de Oliveira; Gomes, Francisco Isaac Fernandes; Chaves, Hellíada Vasconcelos; Silva, Antonio Alfredo Rodrigues e; Zanin, Iriana Carla Junqueira; Barbosa, Francisco Cesar Barroso

    2016-01-01

    ABSTRACT Aspiration of oral bacteria leads to cardiac and respiratory infectious diseases and dentures can act as a reservoir for pathogenic microorganisms. Objective: To determine the occurrence and the in vitro antimicrobial susceptibility of enteric rods and pseudomonads from the denture biofilm of 52 subjects at the Center for Dental Specialties of Sobral/ Ceara, Brazil. Material and Methods: Denture biofilm was collected and samples plated on MacConkey agar. The isolated bacterial colonies were identified using the BBL Crystal enteric/non-fermenter system. Antibiotic bacterial susceptibility was assessed by the disc diffusion method of amoxicillin, amoxicillin/clavulanic acid, doxycycline, tetracycline, tobramycin, imipenem, cefotaxime, and ciprofloxacin. The Minimum Inhibitory Concentration (MIC) of cefotaxime, tobramycin, doxycycline, imipenem, and ciprofloxacin was determined for 40 species by E-test. Results: 34 subjects (65.4%) harbored enteric rods in their prostheses. Klebsiella pneumoniae (26.5%), Escherichia coli (23.5%), and Enterobacter aerogenes (23.5%) were the most prevalent species. All organisms were susceptible to ciprofloxacin and most species were resistant to amoxicillin or amoxicillin/clavulanic acid, demonstrating variable sensitivity patterns to other antimicrobials. However, the MIC showed the emergence of strains with reduced sensitivity to ciprofloxacin (MIC90≥3 μg/ mL) and cefotaxime (MIC90≥2 μg/mL). Conclusion: The findings show high prevalence of nosocomial diseases-related bacterial species and low susceptibility to antimicrobial drugs. Therefore, these results imply caution against the indiscriminate use of broad spectrum antibiotics in dental practice. PMID:27812616

  9. High-level carbapenem resistance in a Citrobacter freundii clinical isolate is due to a combination of KPC-2 production and decreased porin expression.

    PubMed

    Zhang, Rong; Yang, Lijiang; Cai, Jia Chang; Zhou, Hong Wei; Chen, Gong-Xiang

    2008-03-01

    An imipenem-resistant isolate of Citrobacter freundii ZJ163 (MIC 256 microg ml(-1)) isolated from a Chinese hospital was investigated. The C. freundii ZJ163 isolate exhibited high-level resistance to carbapenems, penicillins, cephalosporins, cefoxitin, aztreonam, quinolones and aminoglycosides. Isoelectric focusing (IEF) demonstrated three beta-lactamases with pIs of 5.4 (TEM-1), 6.7 (KPC-2) and 7.9 (CTX-M-14). Two different transconjugants (types A and B) were obtained by conjugation studies. The type A transconjugant exhibited reduced susceptibility or resistance to penicillins, cephalosporins and aztreonam, but was susceptible to carbapenems, quinolones and aminoglycosides. The antimicrobial susceptibility patterns of the type B transconjugant were similar to that of type A, except for its significantly reduced carbapenem susceptibility (imipenem MIC 2 microg ml(-1)). IEF, specific PCRs and DNA sequence analysis indicated that the type A transconjugant produced CTX-M-14 beta-lactamase with a pI of 7.9, that the type B transconjugant produced KPC-2 beta-lactamase with a pI of 6.7 and that the beta-lactamase with a pI of 5.4 was TEM-1. PCR analysis and sequencing confirmed the presence of the ampC gene in the chromosomal DNA from C. freundii ZJ163, although no activity of AmpC beta-lactamase was detected by IEF. Urea/SDS-PAGE analysis of outer-membrane proteins revealed that the levels of the 41 and 38 kDa porins were decreased in C. freundii ZJ163. It was concluded that production of KPC-2 combined with decreased expression of porins contributes to high-level resistance to carbapenems in C. freundii ZJ163.

  10. Comparative analysis on antibiotic resistance characteristics of Listeria spp. and Enterococcus spp. isolated from laying hens and eggs in conventional and organic keeping systems in Bavaria, Germany.

    PubMed

    Schwaiger, K; Schmied, E-M V; Bauer, J

    2010-05-01

    By investigating the prevalence and antimicrobial resistance characteristics of Gram-positive bacteria from organic and conventional keeping systems of laying hens, it was to be determined to what extent these properties are influenced by the different systems. For this purpose, a total of 799 cloacal swabs and 800 egg samples were examined. Prevalences for all selected bacteria from cloacal swabs were much the same for both organic and caged birds: Listeria spp.1.3%[org] versus 1.6%[con]; Enterococcus spp. 95.5%[org] versus 97.5%[con]. Egg contents and eggshells were generally contaminated to a lesser extent, primarily with Enterococcus spp. Listeria isolates were susceptible to almost all tested antibiotics, only three Listeria innocua from conventional keepings were resistant to clindamycin; one isolate additionally to imipenem. High percentages of Enterococcus faecalis were resistant to doxycycline and macrolides. Enterococcus faecium proved to have high resistance rates to clindamycin, fosfomycin and erythromycin; 9.1% were even resistant to the reserve antibiotic synercid. Further, Enterococcus spp. showed higher resistance rates to doxycycline, erythromycin, fosfomycin and rifampicin. No glycopeptide resistant enterococci were detected. A correlation between keeping system and resistance/susceptibility rates could be demonstrated. In detail, E. faecalis from organic laying hen husbandries showed significant lower resistance prevalences to tylosin, streptomycin and doxycycline; susceptibility rates were higher for enrofloxacin and ciprofloxacin. Rifampicin and imipenem were more effective in isolates from conventional keepings (P < 0.05). The amounts of resistant isolates of the Enterococcus raffinosus from organic farms were significantly lower, the amounts of sensitive isolates were significantly higher than from conventional farms concerning eight antibiotics (P < 0.05). When comparing the susceptibility/resistance rates, as well as the mean minimum

  11. Direct ertapenem disk screening method for identification of KPC-producing Klebsiella pneumoniae and Escherichia coli in surveillance swab specimens.

    PubMed

    Lolans, Karen; Calvert, Karen; Won, Sarah; Clark, James; Hayden, Mary K

    2010-03-01

    Klebsiella pneumoniae carbapenemase (KPC) production in Gram-negative bacilli is an increasing problem worldwide. Rectal swab surveillance is recommended as a component of infection prevention programs, yet few screening methods are published. We compared detection of KPC-producing Klebsiella pneumoniae and Escherichia coli in surveillance specimens by 2 methods: (i) inoculation of swabs in tryptic soy broth containing 2 microg/ml imipenem followed by plating to MacConkey agar (MAC) (method 1) and (ii) streaking swabs on MAC onto which a 10-microg ertapenem disk was then placed (method 2). Simulated rectal swab specimens of challenge isolates from a collection of well-characterized K. pneumoniae and E. coli strains and salvage rectal swab specimens collected from patients at 4 different health care facilities over a 7-month period were tested. The gold-standard comparator was bla(KPC) PCR testing of isolates. Method 1 detected 4/9 (44%) KPC-positive challenge isolates. By method 2, 9/9 KPC-positive challenge isolates exhibited zones of inhibition of < or = 27 mm; all KPC-negative isolates exhibited zones of inhibition greater than 27 mm. The sensitivity and specificity of method 1 for detection of KPC-positive K. pneumoniae and E. coli in 149 rectal swab specimens were 65.6% (95% confidence interval [CI], 46.8% to 80.8%) and 49.6% (95% CI, 40.3% to 58.9%), respectively. With method 2, a zone diameter of < or = 27 mm had a sensitivity of 97.0% (95% CI, 82.5% to 99.8%) and specificity of 90.5% (95% CI, 83.3% to 94.9%) for detection of KPC in rectal swab specimens. Direct ertapenem disk testing is simpler, more sensitive, and more specific than selective broth enrichment with imipenem for detection of KPC-producing K. pneumoniae and E. coli in surveillance specimens.

  12. Evaluation of Metallo-β-Lactamase-Production and Carriage of bla-VIM Genes in Pseudomonas aeruginosa Isolated from Burn Wound Infections in Isfahan

    PubMed Central

    Saffari, Mahmood; Firoozeh, Farzaneh; Pourbabaee, Mohammad; Zibaei, Mohammad

    2016-01-01

    Background Metallo-β-lactamase-production among Gram-negative bacteria, including Pseudomonas aeruginosa, has become a challenge for treatment of infections due to these resistant bacteria. Objectives The aim of the current study was to evaluate the metallo-β-lactamase-production and carriage of bla-VIM genes among carbapenem-resistant P. aeruginosa isolated from burn wound infections. Patients and Methods A cross-sectional study was conducted from September 2014 to July 2015. One hundred and fifty P. aeruginosa isolates were recovered from 600 patients with burn wound infections treated at Imam-Musa-Kazem Hospital in Isfahan city, Iran. Carbapenem-resistant P. aeruginosa isolates were screened by disk diffusion using CLSI guidelines. Metallo-β-lactamase-producing P. aeruginosa isolates were identified using an imipenem-EDTA double disk synergy test (EDTA-IMP DDST). For detection of MBL genes including bla-VIM-1 and bla-VIM-2, polymerase chain reaction (PCR) methods and sequencing were used. Results Among the 150 P. aeruginosa isolates, 144 (96%) were resistant to imipenem by the disk diffusion method, all of which were identified as metallo-β-lactamase-producing P. aeruginosa isolates by EDTA-IMP DDST. Twenty-seven (18%) and 8 (5.5%) MBL-producing P. aeruginosa isolates harbored bla-VIM-1 and bla-VIM-2 genes, respectively. Conclusions Our findings showed a high occurrence of metallo-β-lactamase production among P. aeruginosa isolates in burn patient infections in our region. Also, there are P. aeruginosa isolates carrying the bla-VIM-1 and bla-VIM-2 genes in Isfahan province. PMID:28144604

  13. Surveillance of Antibiotic Resistance among Hospital- and Community-Acquired Toxigenic Clostridium difficile Isolates over 5-Year Period in Kuwait

    PubMed Central

    Jamal, Wafaa Y.; Rotimi, Vincent O.

    2016-01-01

    Clostridium difficile infection (CDI) is a leading and an important cause of diarrhea in a healthcare setting especially in industrialized countries. Community-associated CDI appears to add to the burden on healthcare setting problems. The aim of the study was to investigate the antimicrobial resistance of healthcare-associated and community-acquired C. difficile infection over 5 years (2008–2012) in Kuwait. A total of 111 hospital-acquired (HA-CD) and 35 community-acquired Clostridium difficile (CA-CD) clinical isolates from stool of patients with diarrhoea were studied. Antimicrobial susceptibility testing of 15 antimicrobial agents against these pathogens was performed using E test method. There was no evidence of resistance to amoxicillin-clavulanic acid, daptomycin, linezolid, piperacillin-tazobactam, teicoplanin and vancomycin by both HA-CD and CA-CD isolates. Metronidazole had excellent activity against CA-CD but there was a 2.9% resistance rate against HA-CD isolates. Ampicillin, clindamycin, levofloxacin and imipenem resistance rates among the HC-CD vs. CA-CD isolates were 100 vs. 47.4%; 43 vs. 47.4%; 100 vs. 100% and 100 vs. 89%, respectively. An unexpected high rifampicin resistance rate of 15.7% emerged amongst the HA-CD isolates. In conclusion, vancomycin resistance amongst the HA-CD and CA-CD isolates was not encountered in this series but few metronidazole resistant hospital isolates were isolated. High resistance rates of ampicillin, clindamycin, levofloxacin, and imipenem resistance were evident among both CA-CD and HA-CD isolates. Rifampicin resistance is emerging among the HA-CD isolates. PMID:27536994

  14. Expanding the Repertoire of Carbapenem-Hydrolyzing Metallo-ß-Lactamases by Functional Metagenomic Analysis of Soil Microbiota.

    PubMed

    Gudeta, Dereje D; Bortolaia, Valeria; Pollini, Simona; Docquier, Jean-Denis; Rossolini, Gian M; Amos, Gregory C A; Wellington, Elizabeth M H; Guardabassi, Luca

    2016-01-01

    Carbapenemases are bacterial enzymes that hydrolyze carbapenems, a group of last-resort β-lactam antibiotics used for treatment of severe bacterial infections. They belong to three β-lactamase classes based amino acid sequence (A, B, and D). The aim of this study was to elucidate occurrence, diversity and functionality of carbapenemase-encoding genes in soil microbiota by functional metagenomics. Ten plasmid libraries were generated by cloning metagenomic DNA from agricultural (n = 6) and grassland (n = 4) soil into Escherichia coli. The libraries were cultured on amoxicillin-containing agar and up to 100 colonies per library were screened for carbapenemase production by CarbaNP test. Presumptive carbapenemases were characterized with regard to DNA sequence, minimum inhibitory concentration (MIC) of β-lactams, and imipenem hydrolysis. Nine distinct class B carbapenemases, also known as metallo-beta-lactamases (MBLs), were identified in six soil samples, including two subclass B1 (GRD23-1 and SPN79-1) and seven subclass B3 (CRD3-1, PEDO-1, GRD33-1, ESP-2, ALG6-1, ALG11-1, and DHT2-1). Except PEDO-1 and ESP-2, these enzymes were distantly related to any previously described MBLs (33 to 59% identity). RAIphy analysis indicated that six enzymes (CRD3-1, GRD23-1, DHT2-1, SPN79-1, ALG6-1, and ALG11-1) originated from Proteobacteria, two (PEDO-1 and ESP-2) from Bacteroidetes and one (GRD33-1) from Gemmatimonadetes. All MBLs detected in soil microbiota were functional when expressed in E. coli, resulting in detectable imipenem-hydrolyzing activity and significantly increased MICs of clinically relevant ß-lactams. Interestingly, the MBLs yielded by functional metagenomics generally differed from those detected in the same soil samples by antibiotic selective culture, showing that the two approaches targeted different subpopulations in soil microbiota.

  15. The aerobic activity of metronidazole against anaerobic bacteria.

    PubMed

    Dione, Niokhor; Khelaifia, Saber; Lagier, Jean-Christophe; Raoult, Didier

    2015-05-01

    Recently, the aerobic growth of strictly anaerobic bacteria was demonstrated using antioxidants. Metronidazole is frequently used to treat infections caused by anaerobic bacteria; however, to date its antibacterial activity was only tested in anaerobic conditions. Here we aerobically tested using antioxidants the in vitro activities of metronidazole, gentamicin, doxycycline and imipenem against 10 common anaerobic and aerobic bacteria. In vitro susceptibility testing was performed by the disk diffusion method, and minimum inhibitory concentrations (MICs) were determined by Etest. Aerobic culture of the bacteria was performed at 37°C using Schaedler agar medium supplemented with 1mg/mL ascorbic acid and 0.1mg/mL glutathione; the pH was adjusted to 7.2 by 10M KOH. Growth of anaerobic bacteria cultured aerobically using antioxidants was inhibited by metronidazole after 72h of incubation at 37°C, with a mean inhibition diameter of 37.76mm and an MIC of 1μg/mL; however, strains remained non-sensitive to gentamicin. No growth inhibition of aerobic bacteria was observed after 24h of incubation at 37°C with metronidazole; however, inhibition was observed with doxycycline and imipenem used as controls. These results indicate that bacterial sensitivity to metronidazole is not related to the oxygen tension but is a result of the sensitivity of the micro-organism. In future, both culture and antibiotic susceptibility testing of strictly anaerobic bacteria will be performed in an aerobic atmosphere using antioxidants in clinical microbiology laboratories.

  16. Further Increases in Carbapenem-, Amikacin-, and Fluoroquinolone-Resistant Isolates of Acinetobacter spp. and P. aeruginosa in Korea: KONSAR Study 2009

    PubMed Central

    Lee, Kyungwon; Kim, Mi-Na; Kim, Jae-Seok; Hong, Hye Lim; Kang, Jung Oak; Shin, Jong Hee; Park, Yeon-Joon; Yong, Dongeun; Jeong, Seok Hoon

    2011-01-01

    Purpose The increasing prevalence of antimicrobial resistant bacteria has become a serious worldwide problem. The aim of this study was to analyze antimicrobial resistance data generated in 2009 by hospitals and commercial laboratories participating in the Korean Nationwide Surveillance of Antimicrobial Resistance program. Materials and Methods Susceptibility data were collected from 24 hospitals and two commercial laboratories. In the analysis, resistance did not include intermediate susceptibility. Duplicate isolates were excluded from the analysis of hospital isolates, but not from the commercial laboratory isolates. Results Among the hospital isolates, methicillin-resistant Staphylococcus aureus, penicillin G-non-susceptible Streptococcus pneumoniae based on meningitis breakpoint, and ampicillin-resistant Enterococcus faecium remained highly prevalent. The proportion of vancomycin-resistant E. faecium gradually increased to 29%. Ceftazidime-resistant Escherichia coli and Klebsiella pneumoniae increased to 17% and 33%, respectively, and fluoroquinolone-resistant K. pneumoniae, Acinetobacter spp. and Pseudomonas aeruginosa increased to 33%, 67% and 39%, respectively. Amikacin-resistant Acinetobacter spp. increased to 48%. Imipenem-resistant Acinetobacter spp. and P. aeruginosa increased to 51% and 26%, respectively. Higher resistance rates were observed in intensive care unit (ICU) isolates than in non-ICU isolates among the isolates from hospitals. Resistance rates were higher in hospital isolates than in clinic isolates among the isolates from commercial laboratories. Conclusion Among the hospital isolates, ceftazidime-resistant K. pneumoniae and fluoroquinolone-resistant K. pneumoniae, Acinetobacter spp., and P. aeruginosa further increased. The increase in imipenem resistance was slight in P. aeruginosa, but drastic in Acinetobacter spp. The problematic antimicrobial-organism combinations were much more prevalent among ICU isolates. PMID:21786445

  17. Susceptibility trends of Bacteroides fragilis group isolates from Buenos Aires, Argentina.

    PubMed

    Fernández Canigia, L; Castello, L; Di Martino, A; Greco, G; Legaria, M C; Litterio, M; Predari, S C; Rollet, R; Rossetti, A; Carloni, G; Sarchi, M I; Bianchini, H

    2007-01-01

    The aim of this study was to analyze the susceptibility trends to seven antibiotics of Bacteroides fragilis group isolates based on three survey studies performed by the Committee of Anaerobic Bacteria between 1989 and 2002. Fifty three, 82 and 65 B. fragilis group isolates were collected during each period. The antimicrobial agents included were: ampicillin, ampicillin-sulbactam (2:1), cefoxitin, piperacillin, imipenem, clindamycin, and metronidazole. Minimal inhibitory concentrations (MICs) were determined according to the reference agar dilution method described by the Clinical and Laboratory Standards Institute (CLSI, formerly NCCLS). The most active antibiotics for B. fragilis and non-B. fragilis species throughout the three periods were: imipenem with 99.1 and 100% of activity, respectively, and metronidazole with 100% of activity. The susceptibility to ampicillin-sulbactam showed a decrease, from 100% to 90.3% and to 82.4 % in the last period, for both B. fragilis and non-B. fragilis species, respectively. The overall susceptibility rates for cefoxitin, piperacillin, and clindamycin were significantly different between B. fragilis and non-B. fragilis species (84.2% vs. 56.5%; 85.9% vs. 66.7% and 88.8% vs. 64.7%, respectively, p < 0.05). Cefoxitin was the antibiotic that showed more variations as regards periods and species. The susceptibility rates for clindamycin were low, about 60%, for non-B. fragilis species during the last two periods. The variations observed in the susceptibility patterns of the B. fragilis group isolates emphasize the need to continue monitoring the emergence of resistance in order to guide the election of the most appropriate antibiotic therapy scheme for anaerobic infections.

  18. Detection of Metallo-Beta Lactamases Among Carbapenem-Resistant Pseudomonas aeruginosa

    PubMed Central

    Farajzadeh Sheikh, Ahmad; Rostami, Soodabeh; Jolodar, Abbas; Tabatabaiefar, Mohammad Amin; Khorvash, Farzin; Saki, Azadeh; Shoja, Saeed; Sheikhi, Raheleh

    2014-01-01

    Background: Carbapenems are important drugs used for the treatment of Pseudomonas aeruginosa infections, however metallo-β-lactamases (MBL) are able to efficiently hydrolyze these classes of drugs. Immediate detection of the MBL-producing P. aeruginosa is necessary in order to accurately treat infections caused by this organism. Objectives: To determine the prevalence of MBL producing P. aeruginosa in burn and non-burn patients by two phenotypic tests and polymerase chain reaction (PCR) and to compare phenotypic tests with PCR. Materials and Methods: A total of 223 non-duplicate strains of P. aeruginosa were collected from three teaching hospitals of Ahvaz, Iran. Antimicrobial susceptibility and minimum inhibitory concentrations (MICs) of carbapenems (imipenem, meropenem, doripenem and ertapenem) were determined by the Kirby-Bauer and E-test methods. Combined disk (CD) test, MBL E-test and PCR were performed for carbapenem-resistant P. aeruginosa isolates. Results: Amongst all the P. aeruginosa isolates, 58.7% were resistant to imipenem while 31.8%, 13.5% and 74.4% were resistant to meropenem, doripenem and ertapenem, respectively. Amongst all the P. aeruginosa isolates, 44.4% were multidrug resistant and 13.45% were resistant to all of the carbapenems. The CD test with doripenem disk / 750 μg ethylene diamine tetra acetic acid (EDTA) had the highest efficiency compared to the other phenotypic tests. blaIMP and blaVIM genes were detected in 11.7% and 0.4% of isolates, respectively. blaSPM and blaNDM genes were not observed. Conclusions: Epidemiological and regional evaluation of MBL-producing P. aeruginosa through simple and inexpensive methods should be considered for effective treatment of carbapenem-resistant P. aeruginosa infections. PMID:25774271

  19. Shorter Duration of Post-Operative Antibiotics for Cecal Ligation and Puncture Does Not Increase Inflammation or Mortality

    PubMed Central

    Iskander, Kendra N.; Vaickus, Max; Duffy, Elizabeth R.

    2016-01-01

    Antimicrobial therapy for sepsis has beneficial effects, but prolonged use fosters emergence of resistant microorganisms, increases cost, and secondary infections. We tested whether 3 days versus 5 days of antibiotics in the murine model of cecal ligation and puncture (CLP) negatively influences outcomes. Following CLP mice were randomized to receive the antibiotic imipenem-cilastatin (25mg/kg) in dextrose 5% in Lactated Ringer’s solution every 12 hours for either three or five days. Serial monitoring over 28 days included body weight, temperature, pulse oximetry, and facial vein sampling for hematological analysis and glucose. A separate group of mice were euthanized on post-CLP day 5 to measure cytokines and peritoneal bacterial counts. The first study examined no antimicrobial therapy and demonstrated that antibiotics significantly improved survival compared to fluids only (p = 0.004). We next tested imipenem-cilastatin therapy for 3 days versus 5 days. Body weight, temperature, glucose, and pulse oximetry measurements remained generally consistent between both groups as did the hematological profile. Pro-inflammatory plasma cytokines were comparable between both groups for IL-6, IL-1β, MIP-2 and anti-inflammatory cytokines IL-10, and TNF SRI. At 5 days post-CLP, i.e. 2 days after the termination of antibiotics in the 3 day group, there were no differences in the number of peritoneal bacteria. Importantly, shortening the course of antibiotics by 40% (from 5 days to 3 days) did not decrease survival. Our results indicate that reducing the duration of broad-spectrum antibiotics in murine sepsis did not increase inflammation or mortality. PMID:27669150

  20. Antimicrobial susceptibility among Gram-positive organisms collected from pediatric patients globally between 2004 and 2011: results from the Tigecycline Evaluation and Surveillance Trial.

    PubMed

    Brandon, Michael; Dowzicky, Michael J

    2013-07-01

    The Tigecycline Evaluation and Surveillance Trial (TEST) was designed to monitor global longitudinal changes in bacterial susceptibility to a panel of antimicrobial agents, including tigecycline. In this study, we examine susceptibility among Gram-positive isolates collected from pediatric patients globally between 2004 and 2011. A total of 9,422 Gram-positive isolates were contributed by 1,255 centers, predominantly from Europe and North America. One-third of Staphylococcus aureus isolates were methicillin resistant, peaking in prevalence in 2007. All S. aureus isolates (n = 3,614) were susceptible to linezolid, tigecycline, and vancomycin; minocycline, imipenem, and meropenem were also highly active (>92% susceptibility). Ampicillin and penicillin susceptibility increased significantly during the study period (P < 0.0001 for both). Streptococcus pneumoniae isolates (n = 3,373) were highly susceptible to vancomycin (100%), linezolid (>99%), and levofloxacin and tigecycline (both >96%); imipenem susceptibility was low (32%) in Africa while minocycline susceptibility was low in Asia-Pacific Rim (38%). Penicillin resistance occurred in one-fifth of all S. pneumoniae isolates, with penicillin susceptibility ranging from 14% in Africa to 65% in Europe. Streptococcus agalactiae isolates (n = 1,056) were highly susceptible to most antimicrobials, although only 16% were susceptible to minocycline. Enterococcus faecalis isolates (n = 1,112) were highly susceptible (>97%) to ampicillin, linezolid, penicillin, tigecycline, and vancomycin globally, but only 34% were minocycline susceptible; minocycline susceptibility decreased significantly from 2004 to 2011 (P < 0.001). Tigecycline and linezolid were highly active against Enterococcus faecium (n = 267) globally (100% and 98% susceptible, respectively). Tigecycline and linezolid were highly active against Gram-positive pathogens from pediatric patients in TEST 2004 to 2011, with vancomycin and the carbapenems performing well

  1. Diffusion of beta-lactam antibiotics through the porin channels of Escherichia coli K-12.

    PubMed Central

    Yoshimura, F; Nikaido, H

    1985-01-01

    Diffusion rates of various beta-lactam antibiotics through the OmpF and OmpC porin channels of Escherichia coli K-12 were measured by the use of reconstituted proteoliposomes. The results can be interpreted on the basis of the gross physicochemical properties of the antibiotics along the following lines. (i) As noted previously (Nikaido et al., J. Bacteriol., 153:232-240, 1983), there was a monotonous dependence of the penetration rate on the hydrophobicity of the molecule among the classical monoanionic beta-lactams, and a 10-fold increase in the octanol-water partition coefficient of the uncharged molecule decreased the penetration rate by a factor of 5 to 6. (ii) Compounds with exceptionally bulky side chains, such as mezlocillin, piperacillin, and cefoperazone, showed much slower penetration rates than expected from their hydrophobicity. (iii) The substituted oxime side chain on the alpha-carbon of the substituent group at position 7 of the cephem nucleus decreased the penetration rate almost by an order of magnitude; this appears to be largely due to the steric effect. (iv) The presence of a methoxy group at position 7 of the cephalosporins also reduced the penetration rate by 20%, probably also due to the steric hindrance. (v) Zwitterionic compounds penetrated very rapidly, and the correlation between the rate and hydrophobicity appeared to be much weaker than with the monoanionic compounds. Imipenem showed the highest permeability among the compounds tested, presumably due, at least in part, to its compact molecular structure. (vi) Compounds with two negative charges penetrated more slowly than did analogs with only one negatively charged group. Among them, only moxalactam, ceftriaxone, and azthreonam showed penetration rates corresponding to, or higher than, 10% of that of imipenem. PMID:2580479

  2. Efficacy of LL-37 and granulocyte colony-stimulating factor in a neutropenic murine sepsis due to Pseudomonas aeruginosa.

    PubMed

    Cirioni, Oscar; Ghiselli, Roberto; Tomasinsig, Linda; Orlando, Fiorenza; Silvestri, Carmela; Skerlavaj, Barbara; Riva, Alessandra; Rocchi, Marco; Saba, Vittorio; Zanetti, Margherita; Scalise, Giorgio; Giacometti, Andrea

    2008-10-01

    A promising therapeutic strategy for the management of severe Pseudomonas infection in neutropenic patients may result from the coadministration of colony-stimulating factors (CSFs) that help maintain immune competence and antimicrobial peptides, a novel generation of adjunctive therapeutic agents with antimicrobial and anti-inflammatory properties. A promising peptide with these properties is LL-37, the only member of the cathelicidin family of antimicrobial peptides found in humans. BALB/c male mice were rendered neutropenic by intraperitoneal administration of cyclophosphamide on days -4 and -2 preinfection. Septic shock was induced at time 0 by intraperitoneal injection of 2x10 colony-forming units of P. aeruginosa American Type Culture Collection (ATCC) 27853. All animals were randomized to receive intravenously isotonic sodium chloride solution, 1 mg/kg of LL-37, 20 mg/kg of imipenem, 0.1 mg/kg of granulocyte CSF (G-CSF), 1 mg/kg of LL-37+0.1 mg/kg of G-CSF, or 20 mg/kg of imipenem+0.1 mg/kg of G-CSF. Lethality and bacterial growth in blood, peritoneum, spleen, liver, and kidney were evaluated. All regimens were significantly superior to controls at reducing the mouse lethality rate and bacterial burden in organs. Particularly, the combination between LL-37 and G-CSF was the most effective in protecting neutropenic mice from the onset of sepsis and in vitro significantly reduced the apoptosis of neutrophils. Combination therapy between LL-37 and G-CSF is a promising therapeutic strategy for the management of severe Pseudomonas infection complicated by neutropenia.

  3. High prevalence of OXA-143 and alteration of outer membrane proteins in carbapenem-resistant Acinetobacter spp. isolates in Brazil.

    PubMed

    Mostachio, Anna Karina; Levin, Anna Sara; Rizek, Camila; Rossi, Flavia; Zerbini, Jessika; Costa, Silvia Figueiredo

    2012-05-01

    Carbapenem resistance amongst Acinetobacter spp. has been increasing in the last decade. This study evaluated the outer membrane protein (OMP) profile and production of carbapenemases in 50 carbapenem-resistant Acinetobacter spp. isolates from bloodstream infections. Isolates were identified by API20NE. Minimum inhibitory concentrations (MICs) for carbapenems were determined by broth microdilution. Carbapenemases were studied by phenotypic tests, detection of their encoding gene by polymerase chain reaction (PCR) amplification, and imipenem hydrolysis. Nucleotide sequencing confirming the enzyme gene type was performed using MegaBACE 1000. The presence of OMPs was studied by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and PCR. Molecular typing was performed using pulsed-field gel electrophoresis (PFGE). All isolates were resistant to carbapenems. Moreover, 98% of the isolates were positive for the gene encoding the enzyme OXA-51-like, 18% were positive for OXA-23-like (only one isolate did not show the presence of the insertion sequence ISAba1 adjacent to this gene) and 76% were positive for OXA-143 enzyme. Five isolates (10%) showed the presence of the IMP-1 gene. Imipenem hydrolysing activity was detected in only three strains containing carbapenemase genes, comprising two isolates containing the bla(IMP) gene and one containing the bla(OXA-51/OXA-23-like) gene. The OMP of 43 kDa was altered in 17 of 25 strains studied, and this alteration was associated with a high meropenem MIC (256 μg/mL) in 5 of 7 strains without 43 kDa OMP. On the other hand, decreased OMP 33-36 kDa was found in five strains. The high prevalence of OXA-143 and alteration of OMPs might have been associated with a high level of carbapenem resistance.

  4. Emergence of multidrug-resistant NDM-1-producing Gram-negative bacteria in Bangladesh.

    PubMed

    Islam, M A; Talukdar, P K; Hoque, A; Huq, M; Nabi, A; Ahmed, D; Talukder, K A; Pietroni, M A C; Hays, J P; Cravioto, A; Endtz, H P

    2012-10-01

    The main objective of this study was to investigate the prevalence of bla (NDM-1) in Gram-negative bacteria in Bangladesh. In October 2010 at the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B) laboratories, 1,816 consecutive clinical samples were tested for imipenem-resistant Gram-negative organisms. Imipenem-resistant isolates were tested for the bla (NDM-1) gene. Among 403 isolates, 14 (3.5 %) were positive for bla (NDM-1), and the predominant species were Klebsiella pneumoniae, Acinetobacter baumannii, and Escherichia coli. All bla (NDM-1)-positive isolates were resistant to multiple antibiotics. Among β-lactamase genes, bla (CTX-M-1-group) was detected in ten isolates (eight bla (CTX-M-15)), bla (OXA-1-group) in six, bla (TEM) in nine, bla (SHV) in seven, and bla (VIM) and bla (CMY) in two isolates each. The 16S rRNA methylase gene, armA, was detected in five K. pneumoniae isolates and in one E. coli isolate. rmtB and rmtC were detected in a Citrobacter freundii and two K. pneumoniae isolates, respectively. qnr genes were detected in two K. pneumoniae isolates (one qnrB and one qnrS) and in an E. coli isolate (qnrA). Transferable plasmids (60-100 MDa) carrying bla (NDM-1) were detected in 7 of the 11 plasmid-containing isolates. Pulsed-field gel electrophoresis (PFGE) analysis grouped K. pneumoniae isolates into three clusters, while E. coli isolates differed significantly from each other. This study reports that approximately 3.5 % of Gram-negative clinical isolates in Bangladesh are NDM-1-producing.

  5. Effect of carbapenem consumption patterns on the molecular epidemiology and carbapenem resistance of Acinetobacter baumannii.

    PubMed

    Mózes, Julianna; Ebrahimi, Fatemeh; Gorácz, Orsolya; Miszti, Cecília; Kardos, Gábor

    2014-12-01

    This study investigated the molecular epidemiology of Acinetobacter baumannii in the University of Debrecen in relation to antibiotic consumption. Overall and ward-specific antibiotic consumption was measured by the number of defined daily doses (DDD) per 100 bed-days between 2002 and 2012. Consumption was analysed against the number of A. baumannii positive patients per 100 bed-days, number of isolates per positive sample, and proportion of carbapenem resistant A. baumannii, using time-series analysis. Altogether 160 A. baumannii isolates from different wards were collected and analysed. Carbapenemase genes bla(OXA-23-like), bla(OXA-24-like), bla(OXA-48-like), bla(OXA-51-like), bla(OXA-58-like) and integrons were sought by PCR. Relatedness of isolates was assessed by PFGE. Prevalence and carbapenem resistance of A. baumannii were statistically associated with carbapenem consumption. Prevalence data followed carbapenem usage with three quarterly lags (r = 0.51-0.53, P<0.001), and meropenem and ertapenem, but not imipenem usage, affected prevalence. Colistin usage, in turn, lagged behind prevalence with one lag (r = 0.68-0.70, P<0.001). Six clusters were identified; the neurology ward with the lowest carbapenem consumption was associated with the carbapenem-susceptible cluster, as well as with the carbapenem-susceptible isolates in the cluster with variable susceptibility. Wards with high carbapenem usage almost exclusively harboured isolates from carbapenem-resistant clusters. All clusters were dominated by isolates of one or two wards, but most wards were represented in multiple clusters. Increases in prevalence and carbapenem resistance of A. baumannii were associated with usage of meropenem and ertapenem but not of imipenem, which led to the spread of multiple clones in the University.

  6. Low Prevalence of Carbapenem-Resistant Bacteria in River Water: Resistance Is Mostly Related to Intrinsic Mechanisms.

    PubMed

    Tacão, Marta; Correia, António; Henriques, Isabel S

    2015-10-01

    Carbapenems are last-resort antibiotics to handle serious infections caused by multiresistant bacteria. The incidence of resistance to these antibiotics has been increasing and new resistance mechanisms have emerged. The dissemination of carbapenem resistance in the environment has been overlooked. The main goal of this research was to assess the prevalence and diversity of carbapenem-resistant bacteria in riverine ecosystems. The presence of frequently reported carbapenemase-encoding genes was inspected. The proportion of imipenem-resistant bacteria was on average 2.24 CFU/ml. Imipenem-resistant strains (n=110) were identified as Pseudomonas spp., Stenotrophomonas maltophilia, Aeromonas spp., Chromobacterium haemolyticum, Shewanella xiamenensis, and members of Enterobacteriaceae. Carbapenem-resistant bacteria were highly resistant to other beta-lactams such as quinolones, aminoglycosides, chloramphenicol, tetracyclines, and sulfamethoxazole/trimethoprim. Carbapenem resistance was mostly associated with intrinsically resistant bacteria. As intrinsic resistance mechanisms, we have identified the blaCphA gene in 77.3% of Aeromonas spp., blaL1 in all S. maltophilia, and blaOXA-48-like in all S. xiamenensis. As acquired resistance mechanisms, we have detected the blaVIM-2 gene in six Pseudomonas spp. (5.45%). Integrons with gene cassettes encoding resistance to aminoglycosides (aacA and aacC genes), trimethoprim (dfrB1b), and carbapenems (blaVIM-2) were found in Pseudomonas spp. Results suggest that carbapenem resistance dissemination in riverine ecosystems is still at an early stage. Nevertheless, monitoring these aquatic compartments for the presence of resistance genes and its host organisms is essential to outline strategies to minimize resistance dissemination.

  7. In vitro and in vivo antibacterial activities of CS-023 (RO4908463), a novel parenteral carbapenem.

    PubMed

    Koga, Tetsufumi; Abe, Tomomi; Inoue, Harumi; Takenouchi, Takashi; Kitayama, Akiko; Yoshida, Tatsuhiko; Masuda, Nobuhisa; Sugihara, Chika; Kakuta, Masayo; Nakagawa, Miyuki; Shibayama, Takahiro; Matsushita, Yoko; Hirota, Takashi; Ohya, Satoshi; Utsui, Yukio; Fukuoka, Takashi; Kuwahara, Syogo

    2005-08-01

    CS-023 (RO4908463, formerly R-115685) is a novel 1beta-methylcarbapenem with 5-substituted pyrrolidin-3-ylthio groups, including an amidine moiety at the C-2 position. Its antibacterial activity was tested against 1,214 clinical isolates of 32 species and was compared with those of imipenem, meropenem, ceftazidime, ceftriaxone, ampicillin, amikacin, and levofloxacin. CS-023 exhibited a broad spectrum of activity against gram-positive and -negative aerobes and anaerobes, including methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant Staphylococcus epidermidis, penicillin-resistant Streptococcus pneumoniae (PRSP), beta-lactamase-negative ampicillin-resistant Haemophilus influenzae, and Pseudomonas aeruginosa. CS-023 showed the most potent activity among the compounds tested against P. aeruginosa and MRSA, with MICs at which 90% of isolates tested were inhibited of 4 microg/ml and 8 microg/ml, respectively. CS-023 was stable against hydrolysis by the beta-lactamases from Enterobacter cloacae and Proteus vulgaris. CS-023 also showed potent activity against extended-spectrum beta-lactamase-producing Escherichia coli. The in vivo efficacy of CS-023 was evaluated with a murine systemic infection model induced by 13 strains of gram-positive and -negative pathogens and a lung infection model induced by 2 strains of PRSP (serotypes 6 and 19). Against the systemic infections with PRSP, MRSA, and P. aeruginosa and the lung infections, the efficacy of CS-023 was comparable to those of imipenem/cilastatin and vancomycin (tested against lung infections only) and superior to those of meropenem, ceftriaxone, and ceftazidime (tested against P. aeruginosa infections only). These results suggest that CS-023 has potential for the treatment of nosocomial bacterial infections by gram-positive and -negative pathogens, including MRSA and P. aeruginosa.

  8. Microorganisms’ colonization and their antibiotic resistance pattern in oro - tracheal tube

    PubMed Central

    Abdollahi, Alireza; Shoar, Saeed; Shoar, Nasrin

    2013-01-01

    Background and Objectives Recently, nosocomial infections have been discussed as a critical issue among intubated patients leading to significant morbidity and mortality. Hence, the pattern of microbiological colonization and antibiotic resistance are much valuable in this regard. We aimed to investigate the pattern of microorganism colonization and antibiotic resistance in patients with endotracheal tube or tracheostomy to propose a proper empirical antibiotic therapy in this setting. Materials and Methods This cross sectional study was conducted among 880 patients admitted in Imam Khomeini hospital between 2008 and 2011 who were subsequently intubated or underwent tracheostomy due to insufficient self ventilation. Samples for microbiological cultures were obtained after extubation and then sent to the central laboratory for further assessment. Antibiograms and microbiological cultures were obtained for each sample. Results Of 880 patients enrolled in this study, 531 (60.3%) were male and 349 (39.7%) were female. Nineteen different organisms were isolated including Acinetobacter (213, 24.2%), Pseudomonas aeruginosa (147, 16.7%), Staphylococcus aureus (106, 12%), Proteus mirabilis (90, 10.2%), and other organisms (324, 36.8%). Antibiotic resistance was mainly seen in Acinetobacter (ciprofloxacin, ceftazidim, cefepim, and penicillin), S. aureus (imipenem) and Klebsiella (pipracillintazobactam and ampicillin-sulbactam). Conclusion This study represents the most common microorganisms colonizing tracheal tube of hospitalized patients and their pattern of antibiotic resistance. Acinetobacter was the most common microorganism isolated from endotracheal tube. Hence, it may be possible to initiate the empiric antibiotic treatment before the results of culture are become available. Ciprofloxacin was also the most prevalent antibiotic revealing resistant pattern. Moreover, most of the microorganisms were sensitive to imipenem and pipracillin-tazobactam. PMID:23825725

  9. First national survey of antibiotic susceptibility of the Bacteroides fragilis group: emerging resistance to carbapenems in Argentina.

    PubMed

    Fernández-Canigia, Liliana; Litterio, Mirta; Legaria, María C; Castello, Liliana; Predari, Silvia C; Di Martino, Ana; Rossetti, Adelaida; Rollet, Raquel; Carloni, Graciela; Bianchini, Hebe; Cejas, Daniela; Radice, Marcela; Gutkind, Gabriel

    2012-03-01

    The antibiotic susceptibility rates of 363 clinical Bacteroides fragilis group isolates collected from 17 centers in Argentina during the period from 2006 to 2009 were as follows: piperacillin-tazobactam, 99%; ampicillin-sulbactam, 92%; cefoxitin, 72%; tigecycline, 100%; moxifloxacin, 91%; and clindamycin, 52%. No metronidazole resistance was detected in these isolates during this time period. Resistance to imipenem, doripenem, and ertapenem was observed in 1.1%, 1.6%, and 2.3% of B. fragilis group strains, respectively. B. fragilis species showed a resistance profile of 1.5% to imipenem, 1.9% to doripenem, and 2.4% to ertapenem. This is the first report of carbapenem resistance in Argentina. The cfiA gene was present in 8 out of 23 isolates, all of them belonging to the B. fragilis species and displaying reduced susceptibility or resistance to carbapenems (MICs ≥ 4 μg/ml). Three out of eight cfiA-positive isolates were fully resistant to carbapenems, while 5 out of 8 isolates showed low-level resistance (MICs, 4 to 8 μg/ml). The inhibition by EDTA was a good predictor of the presence of metallo-β-lactamases in the fully resistant B. fragilis strains, but discrepant results were observed for low-level resistant isolates. B. fragilis was more susceptible to antimicrobial agents than other Bacteroides species. Bacteroides vulgatus species was the most resistant to ampicillin-sulbactam and piperacillin-tazobactam, and B. thetaiotaomicron/ovatus strains showed the highest level of resistance to carbapenems, with an unknown resistance mechanism. B. vulgatus and the uncommon non-Bacteroides fragilis species were the most resistant to moxifloxacin, showing an overall resistance rate of 15.1%.

  10. Prevalence and analysis of microbiological factors associated with phenotypic heterogeneous resistance to carbapenems in Acinetobacter baumannii.

    PubMed

    Fernández Cuenca, Felipe; Sánchez, M del Carmen Gómez; Caballero-Moyano, Francisco Javier; Vila, Jordi; Martínez-Martínez, Luis; Bou, Germán; Baño, Jesús Rodríguez; Pascual, Alvaro

    2012-06-01

    The objectives of this study were to determine the prevalence of Acinetobacter baumannii with phenotypic heterogeneous resistance (PHR) to carbapenems (colonies inside the halo of inhibition) and to analyse its association with several microbiological variables. Acinetobacter baumannii isolates collected in Spain were used to analyse: (i) minimum inhibitory concentrations (MICs) of carbapenems; (ii) heteroresistance to carbapenems; (iii) genes encoding β-lactamases (bla genes); (iv) insertion sequences; and (v) inactivation of genes encoding porins (CarO, OprD and Omp33-36) and genes associated with the AdeABC efflux system (adeB, adeR and adeS). Polymerase chain reaction (PCR) amplification was used for gene detection. The rate of PHR was 20% to imipenem and 24% to meropenem. Susceptibility to imipenem was observed in 39% of PHR isolates. MICs of carbapenems for colonies were similar (± 1 log(2) dilution) to those of their parental isolates. These colonies growing inside the inhibition halo also reproduced the PHR to carbapenems. Differences observed between PHR isolates and non-PHR isolates were: bla(OXA-58-like), 57% vs. 0%; oprD-like, 96% vs. 56%; adeB, 89% vs. 94%; adeR, 82% vs. 94%; adeS, 82% vs. 94%; ISAba2, 61% vs. 31%; and ISAba3, 57% vs. 0%. No interruption of genes encoding porins or the efflux-related genes (adeB, adeR and adeS) was observed. In conclusion, A. baumannii strains with PHR to carbapenems are widespread in Spain. This phenotype is present in carbapenem-susceptible isolates as well as those that are not susceptible to carbapenems. Heteroresistance cannot explain the PHR to carbapenems, which appears to relate more to persistence or tolerance to carbapenems. bla(OXA-58-like), bla(OXA-51-like), ISAba2 and ISAba3 are associated with PHR to carbapenems. Inactivation of genes encoding porins or genes related to AdeABC is infrequent.

  11. Monte Carlo simulation for evaluation of the efficacy of carbapenems and new quinolones against ESBL-producing Escherichia coli.

    PubMed

    Nakamura, Tatsuya; Shimizu, Chihiro; Kasahara, Mayumi; Okuda, Kazuyuki; Nakata, Chiyo; Fujimoto, Hiroko; Okura, Hiroe; Komatsu, Masaru; Shimakawa, Kouichi; Sueyoshi, Noriyuki; Ura, Toshiro; Satoh, Kaori; Toyokawa, Masahiro; Wada, Yasunao; Orita, Tamaki; Kofuku, Tomomi; Yamasaki, Katsutoshi; Sakamoto, Masako; Nishio, Hisaaki; Kinoshita, Shohiro; Takahashi, Hakuo

    2009-02-01

    Extended-spectrum beta-lactamase (ESBL)-producing bacteria are known to be resistant to penicillins, cephalosporins, and monobactams because of their substrate specificity, and these bacteria are sensitive only to a narrow range of antimicrobial agents. The present study was undertaken to evaluate the efficacy of carbapenems and the new quinolones against ESBL-producing Escherichia coli, using a Monte Carlo simulation based on the pharmacokinetic/pharmacodynamic (PK/PD) theory. The time above MIC (TAM, %) served as the PK/PD parameter for carbapenems, with the target level set at 40%. The AUC/MIC served as the PK/PD parameter for the new quinolones, with the target level set at more than 125. In the analysis of drug sensitivity, the MIC50 of all carbapenems other than imipenem was low (0.03 microg/ml), while the MIC50 of the new quinolones was higher (1-2 microg/ml). The probability of achieving the PK/PD target with carba penems after two doses at the usual dose level, as determined by the Monte Carlo simulation, was high for each of the carbapenems tested (99.0% for biapenem, 99.60% for meropenem, and 95.03% for doripenem), except for imipenem. Among the new quinolones, the highest probability of achieving the PK/PD target was obtained with pazufloxacin (42.90%). Thus, the results of the present study have revealed that carbapenems are effective at the regular dose and can be used as the first-choice antibiotics for ESBL-producing E. coli because the resistance ratios for carbapenems are low compared to those of the new quinolones.

  12. Expanding the Repertoire of Carbapenem-Hydrolyzing Metallo-ß-Lactamases by Functional Metagenomic Analysis of Soil Microbiota

    PubMed Central

    Gudeta, Dereje D.; Bortolaia, Valeria; Pollini, Simona; Docquier, Jean-Denis; Rossolini, Gian M.; Amos, Gregory C. A.; Wellington, Elizabeth M. H.; Guardabassi, Luca

    2016-01-01

    Carbapenemases are bacterial enzymes that hydrolyze carbapenems, a group of last-resort β-lactam antibiotics used for treatment of severe bacterial infections. They belong to three β-lactamase classes based amino acid sequence (A, B, and D). The aim of this study was to elucidate occurrence, diversity and functionality of carbapenemase-encoding genes in soil microbiota by functional metagenomics. Ten plasmid libraries were generated by cloning metagenomic DNA from agricultural (n = 6) and grassland (n = 4) soil into Escherichia coli. The libraries were cultured on amoxicillin-containing agar and up to 100 colonies per library were screened for carbapenemase production by CarbaNP test. Presumptive carbapenemases were characterized with regard to DNA sequence, minimum inhibitory concentration (MIC) of β-lactams, and imipenem hydrolysis. Nine distinct class B carbapenemases, also known as metallo-beta-lactamases (MBLs), were identified in six soil samples, including two subclass B1 (GRD23-1 and SPN79-1) and seven subclass B3 (CRD3-1, PEDO-1, GRD33-1, ESP-2, ALG6-1, ALG11-1, and DHT2-1). Except PEDO-1 and ESP-2, these enzymes were distantly related to any previously described MBLs (33 to 59% identity). RAIphy analysis indicated that six enzymes (CRD3-1, GRD23-1, DHT2-1, SPN79-1, ALG6-1, and ALG11-1) originated from Proteobacteria, two (PEDO-1 and ESP-2) from Bacteroidetes and one (GRD33-1) from Gemmatimonadetes. All MBLs detected in soil microbiota were functional when expressed in E. coli, resulting in detectable imipenem-hydrolyzing activity and significantly increased MICs of clinically relevant ß-lactams. Interestingly, the MBLs yielded by functional metagenomics generally differed from those detected in the same soil samples by antibiotic selective culture, showing that the two approaches targeted different subpopulations in soil microbiota. PMID:28082950

  13. A Flow Cytometric and Computational Approaches to Carbapenems Affinity to the Different Types of Carbapenemases

    PubMed Central

    Pina-Vaz, Cidália; Silva, Ana P.; Faria-Ramos, Isabel; Teixeira-Santos, Rita; Moura, Daniel; Vieira, Tatiana F.; Sousa, Sérgio F.; Costa-de-Oliveira, Sofia; Cantón, Rafael; Rodrigues, Acácio G.

    2016-01-01

    The synergy of carbapenem combinations regarding Enterobacteriaceae producing different types of carbapenemases was study through different approaches: flow cytometry and computational analysis. Ten well characterized Enterobacteriaceae (KPC, verona integron-encoded metallo-β-lactamases –VIM and OXA-48-like enzymes) were selected for the study. The cells were incubated with a combination of ertapenem with imipenem, meropenem, or doripenem and killing kinetic curves performed with and without reinforcements of the drugs. A cephalosporin was also used in combination with ertapenem. A flow cytometric assay with DiBAC4-(3), a membrane potential dye, was developed in order to evaluate the cellular lesion after 2 h incubation. A chemical computational study was performed to understand the affinity of the different drugs to the different types of enzymes. Flow cytometric analysis and time-kill assays showed a synergic effect against KPC and OXA-48 producing-bacteria with all combinations; only ertapenem with imipenem was synergic against VIM producing-bacteria. A bactericidal effect was observed in OXA-48-like enzymes. Ceftazidime plus ertapenem was synergic against ESBL-negative KPC producing-bacteria. Ertapenem had the highest affinity for those enzymes according to chemical computational study. The synergic effect between ertapenem and others carbapenems against different carbapenemase-producing bacteria, representing a therapeutic choice, was described for the first time. Easier and faster laboratorial methods for carbapenemase characterization are urgently needed. The design of an ertapenem derivative with similar affinity to carbapenemases but exhibiting more stable bonds was demonstrated as highly desirable. PMID:27555844

  14. Antimicrobial resistance profiles of dairy and clinical isolates and type strains of enterococci.

    PubMed

    de Fátima Silva Lopes, Maria; Ribeiro, Tânia; Abrantes, Marta; Figueiredo Marques, José Joaquim; Tenreiro, Rogério; Crespo, Maria Teresa Barreto

    2005-08-25

    The susceptibility to 30 antimicrobial agents was determined by the disk diffusion method for a collection of 172 enterococcal strains, including 96 isolates from dairy sources, 50 isolates of human and veterinary origin, and 26 reference strains from 24 different enterococcal species. Results were analysed by hierarchic numerical methods to cluster strains and to group antimicrobials according to similarity profiles. Resistance to 17 of the 30 antimicrobials showed to be correlated, leading to four groups reflecting the mode of action: quinolones (ofloxacin, enrofloxacin, ciprofloxacin and norfloxacin); macrolides (erythromycin, spiramycin), phenicols (cloramphenicol) and tetracyclins (tetracycline, oxytetracyclin); aminoglycosides (gentamicin, kanamycin) and lincosamides (clindamycin); penicillins (amoxicillin, ampicillin, penicillin G, piperacillin) and carbapenems (imipenem). Overall, the genus Enterococcus behaved as resistant to lincomycin, colistin, polimixin B and, with a few exceptions in dairy isolates, to methicillin. In general, all isolates were susceptible to vancomycin, cloramphenicol and fusidic acid. Clusters containing only dairy isolates were susceptible to the majority of antimicrobials tested, as opposed to clusters constituted only by clinical enterococcal isolates. Among the clinical isolates, 62% were highly multiresistant. Low level gentamicin resistance was found to be associated with clinical enterococci. Among dairy isolates, those that clustered with clinical isolates were both resistant to gentamicin and identified as Enterococcus faecalis. Resistance to macrolides, quinolones, penicillins and imipenem was found to be associated also with clinical environments, mainly with multiresistant isolates, contrary to what is generally agreed as a characteristic of the genus. Veterinary clinical isolates were mainly grouped with the multiresistant clinical human isolates. The 26 reference enterococcal strains were distributed in clusters with

  15. Antimicrobial susceptibility of gram-negative and gram-positive bacteria collected from countries in Eastern Europe: results from the Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) 2004-2010.

    PubMed

    Balode, Arta; Punda-Polić, Volga; Dowzicky, Michael J

    2013-06-01

    The Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) commenced in 2004 to longitudinally monitor global changes in bacterial susceptibility to a suite of antimicrobial agents. The current study examined the activity of tigecycline and comparators against isolates collected across Eastern Europe between 2004 and 2010. Minimum inhibitory concentrations were determined using Clinical and Laboratory Standards Institute (CLSI) broth microdilution methodologies. Antimicrobial susceptibility was determined using CLSI interpretive criteria, and tigecycline susceptibility was established using European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints. This study included 10 295 Gram-negative and 4611 Gram-positive isolates from 42 centres. Extended-spectrum β-lactamases (ESBLs) were reported among 15.3% of Escherichia coli and 39.3% of Klebsiella pneumoniae isolates; the highest rates were observed in Turkey (30.9%) and Bulgaria (53.8%), respectively. Imipenem-non-susceptible K. pneumoniae were identified only in Turkey. ESBL-positive E. coli were highly susceptible to imipenem (95.1%), meropenem (98.0%) and tigecycline (98.5%). Most antimicrobials showed poor activity against Acinetobacter baumannii and Pseudomonas aeruginosa. Vancomycin resistance was noted among 0.9% of Enterococcus faecalis and 11.7% of Enterococcus faecium isolates. High rates of susceptibility were reported for linezolid (99.7%) and tigecycline (100%) against E. faecium. One-quarter of Staphylococcus aureus isolates were meticillin-resistant S. aureus (MRSA), with the highest rate in Romania (51.5%); all MRSA were susceptible to linezolid, tigecycline and vancomycin. Antimicrobial resistance is high in much of Eastern Europe, with considerable variation seen among countries. Tigecycline and the carbapenems retain excellent activity against many pathogens from Eastern Europe; linezolid and vancomycin are active against most Gram-positive pathogens.

  16. International Nosocomial Infection Control Consortium (INICC) report, data summary of 43 countries for 2007-2012. Device-associated module.

    PubMed

    Rosenthal, Víctor Daniel; Maki, Dennis George; Mehta, Yatin; Leblebicioglu, Hakan; Memish, Ziad Ahmed; Al-Mousa, Haifaa Hassan; Balkhy, Hanan; Hu, Bijie; Alvarez-Moreno, Carlos; Medeiros, Eduardo Alexandrino; Apisarnthanarak, Anucha; Raka, Lul; Cuellar, Luis E; Ahmed, Altaf; Navoa-Ng, Josephine Anne; El-Kholy, Amani Ali; Kanj, Souha Sami; Bat-Erdene, Ider; Duszynska, Wieslawa; Van Truong, Nguyen; Pazmino, Leonardo N; See-Lum, Lucy Chai; Fernández-Hidalgo, Rosalia; Di-Silvestre, Gabriela; Zand, Farid; Hlinkova, Sona; Belskiy, Vladislav; Al-Rahma, Hussain; Luque-Torres, Marco Tulio; Bayraktar, Nesil; Mitrev, Zan; Gurskis, Vaidotas; Fisher, Dale; Abu-Khader, Ilham Bulos; Berechid, Kamal; Rodríguez-Sánchez, Arnaldo; Horhat, Florin George; Requejo-Pino, Osiel; Hadjieva, Nassya; Ben-Jaballah, Nejla; García-Mayorca, Elías; Kushner-Dávalos, Luis; Pasic, Srdjan; Pedrozo-Ortiz, Luis E; Apostolopoulou, Eleni; Mejía, Nepomuceno; Gamar-Elanbya, May Osman; Jayatilleke, Kushlani; de Lourdes-Dueñas, Miriam; Aguirre-Avalos, Guadalupe

    2014-09-01

    We report the results of an International Nosocomial Infection Control Consortium (INICC) surveillance study from January 2007-December 2012 in 503 intensive care units (ICUs) in Latin America, Asia, Africa, and Europe. During the 6-year study using the Centers for Disease Control and Prevention's (CDC) U.S. National Healthcare Safety Network (NHSN) definitions for device-associated health care-associated infection (DA-HAI), we collected prospective data from 605,310 patients hospitalized in the INICC's ICUs for an aggregate of 3,338,396 days. Although device utilization in the INICC's ICUs was similar to that reported from ICUs in the U.S. in the CDC's NHSN, rates of device-associated nosocomial infection were higher in the ICUs of the INICC hospitals: the pooled rate of central line-associated bloodstream infection in the INICC's ICUs, 4.9 per 1,000 central line days, is nearly 5-fold higher than the 0.9 per 1,000 central line days reported from comparable U.S. ICUs. The overall rate of ventilator-associated pneumonia was also higher (16.8 vs 1.1 per 1,000 ventilator days) as was the rate of catheter-associated urinary tract infection (5.5 vs 1.3 per 1,000 catheter days). Frequencies of resistance of Pseudomonas isolates to amikacin (42.8% vs 10%) and imipenem (42.4% vs 26.1%) and Klebsiella pneumoniae isolates to ceftazidime (71.2% vs 28.8%) and imipenem (19.6% vs 12.8%) were also higher in the INICC's ICUs compared with the ICUs of the CDC's NHSN.

  17. [Comparison of the modified Hodge test and the Carba NP test for detection of carbapenemases in Enterobacteriaceae isolates].

    PubMed

    Bayramoğlu, Gülçin; Uluçam, Gülşen; Gençoğlu Özgür, Çiğdem; Kılıç, Ali Osman; Aydın, Faruk

    2016-01-01

    A rapid, practical, and accurate identification of carbapenemase-producing Enterobacteriaceae isolates is crucial for the implementation of appropriate infection control measures and proper treatment of the infections. For this purpose, a large number of phenotypic test methods have been developed, although none has 100% sensitivity and specificity. Variations in sensitivity and specificity of these tests based on the type of beta-lactamase enzymes carried by that isolates might result in differences between regions and countries. The aim of this study was to compare the performances of widely used modified Hodge test (MHT) and Carbapenemase Nordmann-Poirel (Carba NP) test in the detection of carbapenemases in Enterobacteriaceae family members. A total of 65 Enterobacteriaceae isolates (43 bla(OXA-48), 10 bla(VIM), 9 bla(IMP), 1 bla(NDM-1), 1 bla(KPC-2) and 1 bla(OXA-48)+bla(VIM) carrying strains) that showed decreased sensitivity to at least one carbapenem (ertapenem, imipenem or meropenem), and carriage of carbapenemase gene confirmed by polymerase chain reaction (PCR), were included in the study. Seventy-eight isolates showing decreased susceptibility to carbapenems but lacking carbapenemase genes were used as controls. All isolates were identified by using conventional methods as well as automated BD Phoenix System (Becton Dickinson, USA). The antimicrobial susceptibility testing was performed using the same automated system, and was confirmed by disk diffusion method. Results were evaluated according to the CLSI criteria. MHT was performed in accordance with the CLSI guideline, and Carba NP test was carried out by a modified protocol. Instead of imipenem monohydrate, which was used in the original protocol, 6 mg/ml imipenem/cilastatin was used in the modified protocol. In the study, MHT identified 90.8% (59/65) of carbapenemase-producing isolates, while 93.9% (61/65) of the isolates were identified by Carba NP test. With MHT, four Klebsiella pneumoniae

  18. Epidemiology and antimicrobial susceptibility profiles of Gram-negative bacteria causing urinary tract infections in the Asia-Pacific region: 2009-2010 results from the Study for Monitoring Antimicrobial Resistance Trends (SMART).

    PubMed

    Lu, Po-Liang; Liu, Yung-Ching; Toh, Han-Siong; Lee, Yu-Lin; Liu, Yuag-Meng; Ho, Cheng-Mao; Huang, Chi-Chang; Liu, Chun-Eng; Ko, Wen-Chien; Wang, Jen-Hsien; Tang, Hung-Jen; Yu, Kwok-Woon; Chen, Yao-Shen; Chuang, Yin-Ching; Xu, Yingchun; Ni, Yuxing; Chen, Yen-Hsu; Hsueh, Po-Ren

    2012-06-01

    In 2009, the Study for Monitoring Antimicrobial Resistance Trends (SMART) was expanded to include surveillance of Gram-negative pathogens causing urinary tract infections (UTIs) in the Asia-Pacific region. A total of 1762 isolates were collected from 38 centers in 11 countries from patients with UTIs in 2009 and 2010. In vitro susceptibilities were determined by the broth microdilution method and susceptibility profiles were determined using minimum inhibitory concentration (MIC) interpretive criteria, as recommended by the Clinical and Laboratory Standards Institute (CLSI) in 2010 (M100-S20), in 2011 (M100-S21), and in 2012 (M100-S22). Enterobacteriaceae comprised 86.0% of the isolates, of which Escherichia coli (56.5%) and Klebsiella pneumoniae (13.8%) were the two most common species. Amikacin was the most effective antibiotic (91.7%), followed by ertapenem (86.9%), imipenem (86.6%), and piperacillin-tazobactam (84.9%). Rates of susceptibility were 50.3% for cefoxitin and ranged from 50.3% to 74.2% for the third- and fourth-generation cephalosporins. For ciprofloxacin and levofloxacin, the susceptibility rates were 51.4% and 54.4%, respectively. Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae comprised 28.2% of all isolates. We also found a high rate of resistance to carbapenems among Acinetobacter baumannii and Pseudomonas aeruginosa causing UTI. Interestingly, according to 2012 CLSI breakpoints, approximately 33.4% of ESBL producers were still susceptible to ceftazidime. However, this in vitro efficacy of ceftazidime needs to be validated in vivo by clinical data. The lowered CLSI interpretive breakpoints for piperacillin-tazobactam, carbapenems, and some cephalosporins in 2011-2012 for Enterobacteriaceae resulted in an approximate 5% drop in susceptibility rates for each drug, with the exception of imipenem for which the susceptibility rate dropped from 99.4% according to 2010 criteria to 91.2% according to 2011 criteria. With the updated

  19. Co-occurrence of blaNDM-1 with blaOXA-23 or blaOXA-58 in clinical multidrug-resistant Acinetobacter baumannii isolates in Algeria.

    PubMed

    Ramoul, Abir; Loucif, Lotfi; Bakour, Sofiane; Amiri, Sabrina; Dekhil, Mazouz; Rolain, Jean-Marc

    2016-09-01

    The aim of this study was to characterise the mechanisms of carbapenem resistance in Acinetobacter baumannii strains isolated in an Algerian hospital. A total of 43 imipenem-resistant A. baumannii clinical isolates collected between 2010 and 2013 were identified using API 20NE and were confirmed by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF/MS). Antibiotic susceptibility testing was performed by the disk diffusion and Etest methods. Carbapenemase activity was detected using microbiological tests and PCR. Genetic transfer of the blaNDM-1 gene was performed by conjugation using sodium azide-resistant Escherichia coli J53 as recipient strain. Clonal relationships were studied by multilocus sequence typing (MLST) using partial sequences of the csuE and blaOXA-51 genes. All 43 A. baumannii isolates were resistant to imipenem with high minimum inhibitory concentrations (MICs) (>32μg/mL). The strains harboured blaOXA-23, blaNDM-1, blaOXA-58 and/or blaOXA-24 genes. Co-existence of blaNDM-1 and blaOXA-23 or blaOXA-58 was detected in two isolates and one isolate, respectively. NDM-1 plasmid transfer to E. coli J53 was successful only for one of the three strains harbouring both blaNDM-1 and blaOXA-23 or blaOXA-58. The phylogenetic tree obtained from concatenation of the partial sequences of csuE and blaOXA-51 showed that there was no genetic relationship between the isolates and the blaNDM-1 resistance gene. Here we report for the first time the co-occurrence of blaNDM-1 along with blaOXA-23 or blaOXA-58 in recent clinical isolates of A. baumannii from Northeast Algeria. These findings re-emphasise the dissemination and rapid spread of blaNDM-1 carbapenemase genes in multidrug-resistant clinical A. baumannii isolates in Algeria.

  20. Epidemiological Characteristics of blaNDM-1 in Enterobacteriaceae and the Acinetobacter calcoaceticus-Acinetobacter baumannii Complex in China from 2011 to 2012

    PubMed Central

    Ou, Weimei; Cui, Lanqing; Li, Yun; Zheng, Bo; Lv, Yuan

    2014-01-01

    Objectives The study aimed to investigate the prevalence and epidemiological characteristics of blaNDM-1 (encoding New Delhi metallo-β-lactamase 1) in Enterobacteriaceae and the Acinetobacter calcoaceticus-Acinetobacter baumannii complex (ABC) in China from July 2011 to June 2012. Methods PCR was used to screen for the presence of blaNDM-1 in all organisms studied. For blaNDM-1-positive strains, 16S rRNA analysis and Analytical Profile Index (API) strips were used to identify the bacterial genus and species. The ABCs were reconfirmed by PCR detection of blaOXA-51-like. Antibiotic susceptibilities of the bacteria were assessed by determining minimum inhibitory concentration (MIC) of them using two-fold agar dilution test, as recommended by the Clinical and Laboratory Standards Institute (CLSI). Molecular typing was performed using pulsed-field gel electrophoresis (PFGE). S1 nuclease-pulsed-field gel electrophoresis (S1-PFGE) and Southern blot hybridization were conducted to ascertain the gene location of blaNDM-1. Conjugation experiments were conducted to determine the transmission of blaNDM-1-positive strains. Results Among 2,170 Enterobacteriaceae and 600 ABCs, seven Enterobacteriaceae strains and two A. calcoaceticus isolates from five different cities carried the blaNDM-1 gene. The seven Enterobacteriaceae strains comprised four Klebsiella pneumoniae, one Enterobacter cloacae, one Enterobacter aerogen and one Citrobacter freundii. All seven were non-susceptible to imipenem, meropenem or ertapenem. Two A. calcoaceticus species were resistant to imipenem and meropenem. Three K. pneumoniae showed the same PFGE profiles. The blaNDM-1 genes of eight strains were localized on plasmids, while one was chromosomal. Conclusions Compared with previous reports, the numbers and species containing the blaNDM-1 in Enterobacteriaceae have significantly increased in China. Most of them are able to disseminate the gene, which is cause for concern. Consecutive surveillance should

  1. Effect of antibiotic order form guiding rational use of expensive drugs on cost containment.

    PubMed

    Sirinavin, S; Suvanakoot, P; Sathapatayavongs, B; Malatham, K

    1998-09-01

    New injectable antimicrobial agents are generally costly and broad-spectrum. Overusage results in unnecessary economic loss and multi-drug resistant organisms. Effective strategies for decreasing costs without compromising patient care are required. This study aimed to evaluate the economic impact of a system using an antimicrobial order form to assist rational usage of expensive antimicrobial agents. The study was performed during 1988-1996 at a 900-bed, tertiary-care, medical school hospital in Bangkok. The target drugs were 3 costly, broad-spectrum antibacterial drugs, namely imipenem, vancomycin, and injectable ciprofloxacin. The restriction of these 3 drugs was started in 1992 and was extended to netilmicin and ceftazidime in 1995. A filled antimicrobial order form (AOF) was required by pharmacists before dispensing the drugs. The AOF guided the physicians to give explicit information about anatomic diagnosis, etiologic diagnosis, and suspected antimicrobial resistance patterns of the organisms. It also contained information about indications of the restricted drugs. The filled forms were audited daily during working days by the chairman of The Hospital Antibiotic Committee. Feedback was given to the prescribers by infectious disease specialists at least twice a week. The strategy was endorsed by the executive committee of the hospital. Impact of AOF without endorsement, audit and feedback, was evaluated in 1996. The expenditures of the drugs were adjusted to the average admitted patient-days per fiscal year of the study period. The system with endorsement was well accepted and could be maintained for 4 years. The adjusted expenditures per year of the 3 restricted antibiotics were 1.41-1.87 million baht less (22-29%) in 1992-1994 than the pre-intervention year 1991. The cost reduction of imipenem and injectable ciprofloxacin could also be maintained for 1995 but not vancomycin for which use increased. The costs of these 3 restricted drugs increased very

  2. Clinical Outcomes of Enterobacteriaceae Infections Stratified by Carbapenem MICs

    PubMed Central

    Patel, Twisha S.

    2014-01-01

    The Clinical and Laboratory Standards Institute (CLSI) lowered the MIC breakpoints for meropenem and imipenem from 4 mg/liter to 1 mg/liter for Enterobacteriaceae in 2010. The breakpoint change improves the probability of pharmacodynamic target attainment and eliminates the need for microbiology labs to perform confirmatory testing for Klebsiella pneumoniae carbapenemase (KPC) production or other beta-lactamases that hydrolyze carbapenems. However, there are limited data evaluating clinical outcomes of the affected breakpoints, and it is unknown if patients infected with Enterobacteriaceae with reduced susceptibility are more likely to have poor outcomes when treated with a carbapenem. We conducted a single-center retrospective matched-cohort analysis in adult patients with Enterobacteriaceae infections treated with meropenem, imipenem, or doripenem. Patients with Enterobacteriaceae infection with a carbapenem MIC of 2 to 8 mg/liter were matched based on pathogen, source of infection, comorbidities, and disease severity (1:1 ratio) to those with a carbapenem MIC of ≤1 mg/liter. A total of 36 patients were included in the study. The group with carbapenem MICs of 2 to 8 mg/liter had a significantly higher 30-day mortality than the group with carbapenem MICs of ≤1 mg/liter (38.9% compared to 5.6%, P = 0.04). Total hospital length of stay (LOS) and intensive care unit (ICU) LOS were longer in the group with MICs of 2 to 8 mg/liter than in the group with MICs of ≤1 mg/liter (57.6 days compared to 34.4 days [P = 0.06] and 56.6 days compared to 21.7 days [P < 0.01], respectively). Patients infected with Enterobacteriaceae with a carbapenem MIC of 2, 4, or 8 mg/liter had higher mortality rates and longer ICU LOS than matched cohorts with carbapenem MICs of ≤1 mg/liter, which supports CLSI's recommendation to lower susceptibility breakpoints for carbapenems. PMID:25378572

  3. Relationship between structure and convulsant properties of some beta-lactam antibiotics following intracerebroventricular microinjection in rats.

    PubMed Central

    De Sarro, A; Ammendola, D; Zappala, M; Grasso, S; De Sarro, G B

    1995-01-01

    The epileptogenic activities of several beta-lactam antibiotics were compared following their intracerebroventricular administration in rats. Different convulsant potencies were observed among the various beta-lactam antibiotics tested, but the epileptogenic patterns were similar. The patterns consisted of an initial phase characterized by wet-dog shakes followed by head tremor, nodding, and clonic convulsions. After the largest doses of beta-lactam antibiotics injected, clonus of all four limbs and/or the trunk, rearing, jumping, falling down, escape response, transient tonic-clonic seizures, and sometimes generalized seizures were observed, followed by a postictal period with a fatal outcome. At a dose of 0.033 mumol per rat, cefazolin was the most powerful epileptogenic compound among the drugs tested. It was approximately three times more potent than benzylpenicillin in generating a response and much more potent than other cephalosporins, such as ceftriaxone, cefoperazone, and cefamandole. No epileptogenic signs were observed with equimolar doses of cefotaxime, cefonicid, cefixime, and ceftizoxime in this model. The more convulsant compounds (i.e., cefazolin and ceftezole) are both characterized by the presence of a tetrazole nucleus at position 7 and show a marked chemical similarity to pentylenetetrazole. Imipenem and meropenem, the two carbapenems tested, also showed epileptogenic properties, but imipenem was more potent than meropenem, with a convulsant potency similar to those of ceftezole and benzylpenicillin. In addition, the monobactam aztreonam possessed convulsant properties more potent than those of cefoperazone and cefamandole. This suggest that the beta-lactam ring is a possible determinant of production of epileptogenic activity, with likely contributory factors in the substitutions at the 7-aminocephalosporanic or 6-aminopenicillanic acid that may increase or reduce the epileptogenic properties of the beta-lactam antibiotics. While the structure

  4. Detection of Carbapenemases in Clinical Enterobacteriaceae Isolates Using the VITEK AST-N202 Card

    PubMed Central

    Bae, Il Kwon; Kang, Hyun-Kyung; Jang, In-Ho; Lee, Woonhyoung; Kim, Keonhan; Jeong, Seok Hoon; Lee, Kyungwon

    2015-01-01

    Background The rapid and accurate detection of carbapenemase-producing Enterobacteriaceae (CPE) in clinical microbiology laboratories is essential for the treatment and control of infections caused by these microorganisms. This study was performed to evaluate the ability of the VITEK AST-N202 card to detect CPE isolates. Materials and Methods A total of 43 (Klebsiella pneumoniae, n = 37; Escherichia coli, n = 3; and Enterobacter cloacae, n = 3) CPE isolates and 79 carbapenemase-non-producing Enterobacteriaceae (CNE) isolates were included in this study. The CPE isolates harbored KPC-2 (n = 11), KPC-3 (n = 20), GES-5 (n = 5), VIM-2 (n = 2), IMP-1 (n = 1), NDM-1 (n = 2), or OXA-232 (n = 2). Of the 79 CNE isolates, eight K. pneumoniae isolates were resistant to ertapenem, imipenem, and meropenem, while the remaining 71 isolates were susceptible to the carbapenems. Antimicrobial susceptibilities were tested using the VITEK AST-N202 card, and the results were interpreted as positive when the isolates showed resistant or intermediate results. Modified-Hodge tests (MHTs) were performed using ertapenem or meropenem disks for the screening of carbapenemase production. Polymerase chain reaction (PCR) and direct sequencing were used to identify β-lactamase genes. Results Sensitivity of MHT with ertapenem and meropenem disks for the detection of carbapenemase was 81.4% (35/43) and 81.4% (35/43), respectively, and a combination with both antibiotic disks increased the sensitivity to 88.4% (38/43). Specificity of the MHT was 100% (79/79) for the CNE isolates. Sensitivity of ertapenem, imipenem, and meropenem as assessed by the VITEK AST-N202 card was 100% (43/43), 93% (40/43), and 95.3% (41/43), respectively. Specificity (89.8%, 71/79) of the test with each carbapenem was improved to 100% (71/71) when eight carbapenem-resistant CNE isolates were excluded from the testing. Conclusion The VITEK AST-N202 card showed high sensitivity for the detection of carbapenemases in

  5. Fosfomycin plus β-Lactams as Synergistic Bactericidal Combinations for Experimental Endocarditis Due to Methicillin-Resistant and Glycopeptide-Intermediate Staphylococcus aureus

    PubMed Central

    del Río, A.; García-de-la-Mària, C.; Entenza, J. M.; Gasch, O.; Armero, Y.; Soy, D.; Mestres, C. A.; Pericás, J. M.; Falces, C.; Ninot, S.; Almela, M.; Cervera, C.; Gatell, J. M.; Moreno, A.; Moreillon, P.; Marco, F.

    2015-01-01

    The urgent need of effective therapies for methicillin-resistant Staphylococcus aureus (MRSA) infective endocarditis (IE) is a cause of concern. We aimed to ascertain the in vitro and in vivo activity of the older antibiotic fosfomycin combined with different beta-lactams against MRSA and glycopeptide-intermediate-resistant S. aureus (GISA) strains. Time-kill tests with 10 isolates showed that fosfomycin plus imipenem (FOF+IPM) was the most active evaluated combination. In an aortic valve IE model with two strains (MRSA-277H and GISA-ATCC 700788), the following intravenous regimens were compared: fosfomycin (2 g every 8 h [q8h]) plus imipenem (1 g q6h) or ceftriaxone (2 g q12h) (FOF+CRO) and vancomycin at a standard dose (VAN-SD) (1 g q12h) and a high dose (VAN-HD) (1 g q6h). Whereas a significant reduction of MRSA-227H load in the vegetations (veg) was observed with FOF+IPM compared with VAN-SD (0 [interquartile range [IQR], 0 to 1] versus 2 [IQR, 0 to 5.1] log CFU/g veg; P = 0.01), no statistical differences were found with VAN-HD. In addition, FOF+IPM sterilized more vegetations than VAN-SD (11/15 [73%] versus 5/16 [31%]; P = 0.02). The GISA-ATCC 700788 load in the vegetations was significantly lower after FOF+IPM or FOF+CRO treatment than with VAN-SD (2 [IQR, 0 to 2] and 0 [IQR, 0 to 2] versus 6.5 [IQR, 2 to 6.9] log CFU/g veg; P < 0.01). The number of sterilized vegetations after treatment with FOF+CRO was higher than after treatment with VAN-SD or VAN-HD (8/15 [53%] versus 4/20 [20%] or 4/20 [20%]; P = 0.03). To assess the effect of FOF+IPM on penicillin binding protein (PBP) synthesis, molecular studies were performed, with results showing that FOF+IPM treatment significantly decreased PBP1, PBP2 (but not PBP2a), and PBP3 synthesis. These results allow clinicians to consider the use of FOF+IPM or FOF+CRO to treat MRSA or GISA IE. PMID:26525803

  6. Emergence of Carbapenem Resistant Non-Fermenting Gram-Negative Bacilli Isolated in an ICU of a Tertiary Care Hospital

    PubMed Central

    Agarwal, Sonika; Khanduri, Sushant; Gupta, Shalini

    2017-01-01

    Introduction The emergence and spread of Multi-Drug Resistant (MDR) Non-Fermenting Gram-Negative Bacilli (NFGNB) in Intensive Care Units (ICU) and their genetic potential to transmit diverse antibiotic resistance regardless of their ability to ferment glucose poses a major threat in hospitals. The complex interplay of clonal spread, persistence, transmission of resistance elements and cell-cell interaction leads to the difficulty in controlling infections caused by these multi drug-resistant strains. Among non-fermenting Gram-negative rods, the most clinically significant species Pseudomonas aeruginosa, Acinetobacter baumannii and Stenotrophomonas maltophilia are increasingly acquiring resistant to carbapenems. Carbapenems once considered as a backbone of treatment of life threatening infections appears to be broken as the resistance to carbapenems is on rise. Aim To document the prevalence of carbapenem resistance in non-fermenting Gram-negative bacilli isolated from patients with respiratory tract infections in the ICU of Himalayan Institute of Medical Sciences, Dehradun. Materials and Methods This is a cross-sectional study conducted in ICU patients between October 2015 to March 2016. A total of 366 lower respiratory tract samples were collected from 356 patients with clinical evidence of lower respiratory tract infections in form of Endotracheal (ET) aspirate, Tracheal Tube (TT) aspirate and Bronchoalveolar Lavage (BAL) specimen. Organism identification and the susceptibility testing was done by using an automated system VITEK 2. Results Out of 366 samples received 99 NFGNB were isolated and most common sample was ET aspirate sample 256 (64.5%). Acinetobacter baumannii was the most common NFGNB isolated 63 (63.63%) followed by Pseudomonas aeruginosa 25 (25.25%), Elizabethkingia meningoseptica seven (7.07%) and Strenotrophomonas maltophilia four (4.04%). We observed that 90.5% Acinetobacter baumannii were resistant to imipenem and 95.2% resistant to meropenem

  7. Development of EUCAST disk diffusion method for susceptibility testing of the Bacteroides fragilis group isolates.

    PubMed

    Nagy, Elisabeth; Justesen, Ulrik Stenz; Eitel, Zsuzsa; Urbán, Edit

    2015-02-01

    With the emergence of antibiotic resistance among Bacteroides fragilis group isolates the need of susceptibility testing in routine laboratories is increasing. The aims of the present study were to evaluate the disk diffusion method for susceptibility testing in case of different clinical isolates of Bacteroides spp by comparing zone diameter results with MICs obtained earlier during an Europe-wide antibiotic susceptibility surveillance, and to propose zone diameter breakpoints, which correlate for the EUCAST MIC breakpoints. We tested 381 clinical isolates of the B. fragilis group to amoxicillin/clavulanic acid, cefoxitin, clindamycin, imipenem, metronidazole, moxifloxacin, piperacillin/tazobactam, tigecycline by agar dilution method previously. The inhibition zones of the same antibiotics including meropenem disc were determined by the disc diffusion on Brucella blood agar supplemented with haemin and vitamin K1. Plates were incubated at 37 °C in an anaerobic atmosphere for 24 h. The zone diameters were read at 100% inhibition. In case of discrepant results MICs were determined by gradient test and compared with the inhibition zones on the same plate. We found a good agreement between the inhibition zone diameters and the MICs for imipenem, metronidazole, moxifloxacin and tigecyclin. The inhibition zone diameters of meropenem also separated clearly the isolates, which can be considered wild-type isolates. In case of amoxicillin/clavulanic acid and piperacillin/tazobactam intermediate and susceptible isolates according to the MIC determination, overlap during the zone diameter determination. Isolates with an inhibition zone <23 mm for amoxicillin/clavulanic acid and <25 mm for piperacillin/tazobactam should be retested by a MIC determination method. The 10 μg clindamycin disc clearly separated the resistant and the susceptible population of B. fragilis group strains. In the case of cefoxitin only resistant population could be separated with an inhibition

  8. Transition of blaOXA-58-like to blaOXA-23-like in Acinetobacter baumannii Clinical Isolates in Southern China: An 8-Year Study

    PubMed Central

    Wu, Weiyuan; He, Yi; Lu, Jian; Lu, Yuemei; Wu, Jinsong; Liu, Yingxia

    2015-01-01

    Background The prevalence of carbapenem-resistant Acinetobacter baumannii in hospitals has been increasing worldwide. This study aims to investigate the carbapenemase genes and the clonal relatedness among A. baumannii clinical isolates in a Chinese hospital. Methods Carbapenemase genes and the upstream locations of insertion sequences were detected by polymerase chain reaction (PCR), and the clonal relatedness of isolates was determined by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing. Results A total of 231 nonduplicate carbapenemase gene-harboring A. baumannii clinical isolates recovered from Shenzhen People’s Hospital, were investigated between 2002 and 2009. blaOXA-23-like, blaOXA-58-like, blaOXA-40-like, and ISAba1-blaOXA-51-like were identified in 119, 107, 1, and 4 isolates, respectively. IS1008-ΔISAba3, ISAba3, and ISAba1 were detected upstream of the blaOXA-58-like gene in 69, 35, and 3 isolates, respectively. All blaOXA-23-like genes but one had an upstream insertion of ISAba1. blaOXA-58-like was the most common carbapenemase gene in A.baumannii before 2008, thereafter blaOXA-23-like became rapidly prevalent and replaced blaOXA-58-like in 2009. The majority of blaOXA-58-like-carrying isolates showed lower level of resistance to imipenem and meropenem (minimum inhibitory concentrations (MICs), 1 μg/ml to 16 μg/ml), compared with the majority of blaOXA-23-like-carrying isolates (MICs, 16 μg/ml to 64 μg/ml for both imipenem and meropenem). All 231 blaOXA carbapenemase gene-harboring isolates belonged to 14 PFGE types (A–N), and three dominant clones A, J, and H accounted for 43.3%, 42.0%, and 8.2% of the tested isolates, respectively. Clone A (sequence type ST92/ST208) with blaOXA-58-like was the most prevalent before 2008. Clone H (ST229) with blaOXA-23-like became striking between 2007 and 2008. Clone J (ST381) with blaOXA-23-like rapidly spread and replaced clones A and H in 2009. Conclusion This study is the first to

  9. Antimicrobial susceptibility profiling and genomic diversity of Acinetobacter baumannii isolates: A study in western Iran

    PubMed Central

    Mohajeri, Parviz; Farahani, Abbas; Feizabadi, Mohammad Mehdi; Ketabi, Hosnieh; Abiri, Ramin; Najafi, Farid

    2013-01-01

    Background and Objective Acinetobacter baumannii is an aerobic non-motile Gram-negative bacterial pathogen that is resistant to most antibiotics. Carbapenems are the most common antibiotics for the treatment of infections caused by this pathogen. Mechanisms of antibiotic-resistance in A. baumannii are mainly mediated by efflux pumps-lactamases. The aim of this study was to determine antibiotic susceptibility, the possibility of existence of OXAs genes and fingerprinting by Pulsed-Field Gel Electrophoresis (PFGE) among clinical isolates of Acinetobacter collected from Kermanshah hospitals. Materials and Methods One hundred and four isolates were collected from patients attending Imam Reza, Taleghani and Imam Khomeini hospitals of Kermanshah (Iran). Isolates were identified by biochemical tests and API 20NE kit. The susceptibility to different antibiotics was assessed with Kirby-Bauer disk diffusion method. PCR was performed for detection of bla OXA-23, bla OXA-24, bla OXA-51 and bla OXA-58 beta-lactamase genes. Clonal relatedness was estimated by PFGE (with the restriction enzyme Apa I) and DNA patterns were analyzed by Gel compare II 6.5 software. Results All isolates showed high-level of resistance to imipenem, meropenem as well as to other antimicrobial agents, while no resistance to polymyxin B, colistin, tigecylcine and minocycline was observed. The bla OXA-23like and bla OXA-24 like were found among 77.9% and 19.2% of the isolates, respectively. All isolates were positive for bla OXA-51, but none produced any amplicon for bla OXA-58. PFGE genotype analysis suggested the existence of eight clones among the 104 strains [A (n = 35), B (n = 29), C (n = 19), D (n = 10), E (n = 4), F (n = 3), G (n = 3), H (n = 1)]. Clone A was the dominant clone in hospital settings particularly infection wards so that the isolates in this group, compared to the other clones, showed higher levels of resistance to antibiotics. Conclusion The bla OXA-51-like and bla OXA-23like were

  10. Overexpression of an outer membrane protein associated with decreased susceptibility to carbapenems in Proteus mirabilis.

    PubMed

    Tsai, Yi-Lin; Wang, Min-Cheng; Hsueh, Po-Ren; Liu, Ming-Che; Hu, Rouh-Mei; Wu, Yue-Jin; Liaw, Shwu-Jen

    2015-01-01

    Proteus mirabilis isolates commonly have decreased susceptibility to imipenem. Previously, we found P. mirabilis hfq mutant was more resistant to imipenem and an outer membrane protein (OMP) could be involved. Therefore, we investigated the role of this OMP in carbapenem susceptibility. By SDS-PAGE we found this OMP (named ImpR) was increased in hfq mutant and LC-MS/MS revealed it to be the homologue of Salmonella YbfM, which is a porin for chitobiose and subject to MicM (a small RNA) regulation. We demonstrated that ImpR overexpression resulted in increased carbapenem MICs in the laboratory strain and clinical isolates. Chitobiose induced expression of chb (a chitobiose utilization operon). Real-time RT-PCR and SDS-PAGE were performed to elucidate the relationship of hfq, impR, chb and MicM in P. mirabilis. We found MicM RNA was decreased in hfq mutant and chbBC-intergenic region (chbBC-IGR) overexpression strain (chbIGRov), while impR mRNA was increased in hfq mutant, micM mutant and chbIGRov strain. In addition, mutation of hfq or micM and overexpression of chbBC-IGR increased ImpR protein level. Accordingly, chitobiose made wild-type have higher levels of ImpR protein and are more resistant to carbapenems. Hfq- and MicM-complemented strains restored wild-type MICs. Mutation of both impR and hfq eliminated the increase in carbapenem MICs observed in hfq mutant and ImpR-complementation of hfq/impR double mutant resulted in MICs as hfq mutant, indicating that the ImpR-dependent decreased carbapenem susceptibility of hfq mutant. These indicate MicM was antisense to impR mRNA and was negatively-regulated by chbBC-IGR. Together, overexpression of ImpR contributed to the decreased carbapenem susceptibility in P. mirabilis.

  11. Device-associated infection rates and bacterial resistance in six academic teaching hospitals of Iran: Findings from the International Nocosomial Infection Control Consortium (INICC).

    PubMed

    Jahani-Sherafat, Somayeh; Razaghi, Maryam; Rosenthal, Victor D; Tajeddin, Elahe; Seyedjavadi, Simasadat; Rashidan, Marjan; Alebouyeh, Masoud; Rostampour, Maryam; Haghi, Arezo; Sayarbayat, Masoumeh; Farazmandian, Somayeh; Yarmohammadi, Tahere; Arshadi, Fardokht K; Mansouri, Nahid; Sarbazi, Mohammad R; Vilar, Mariano; Zali, Mohammad R

    2015-01-01

    Device-associated health care-acquired infections (DA-HAIs) pose a threat to patient safety, particularly in the intensive care unit (ICU). However, few data regarding DA-HAI rates and their associated bacterial resistance in ICUs from Iran are available. A DA-HAI surveillance study was conducted in six adult and pediatric ICUs in academic teaching hospitals in Tehran using CDC/NHSN definitions. We collected prospective data regarding device use, DA-HAI rates, and lengths of stay from 2584 patients, 16,796 bed-days from one adult ICU, and bacterial profiles and bacterial resistance from six ICUs. Among the DA-HAIs, there were 5.84 central line-associated bloodstream infections (CLABs) per 1000 central line-days, 7.88 ventilator-associated pneumonias (VAPs) per 1000 mechanical ventilator-days and 8.99 catheter-associated urinary tract infections (CAUTIs) per 1000 urinary catheter-days. The device utilization ratios were 0.44 for central lines, 0.42 for mechanical ventilators and 1.0 for urinary catheters. The device utilization ratios of mechanical ventilators and urinary catheters were higher than those reported in the ICUs of the INICC and the CDC's NHSN reports, but central line use was lower. The DA-HAI rates in this study were higher than the CDC's NHSN report. However, compared with the INICC report, the VAP rate in our study was lower, while the CLAB rate was similar and the CAUTI rate was higher. Nearly 83% of the samples showed a mixed-type infection. The most frequent pathogens were Acinetobacter baumannii, Staphylococcus aureus and Pseudomonas aeruginosa, followed by Klebsiella pneumoniae and Enterococcus spp. In the S. aureus isolates, 100% were resistant to oxacillin. Overall resistances of A. baumannii and K. pneumonia to imipenem were 70.5% and 76.7%, respectively. A multiple drug resistance phenotype was detected in 68.15% of the isolates. The DA-HAI rates in Iran were shown to be higher than the CDC-NHSN rates and similar to the INICC rates

  12. Antimicrobial susceptibility of Gram-negative ESKAPE pathogens isolated from hospitalized patients with intra-abdominal and urinary tract infections in Asia-Pacific countries: SMART 2013-2015.

    PubMed

    Karlowsky, James A; Hoban, Daryl J; Hackel, Meredith A; Lob, Sibylle H; Sahm, Daniel F

    2017-01-01

    Gram-negative ESKAPE pathogens (Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.) are responsible for increases in antimicrobial-resistant infections worldwide. We determined in vitro susceptibilities to eight parenteral antimicrobial agents using Clinical and Laboratory Standards Institute broth microdilution methodology for Gram-negative ESKAPE pathogens isolated from hospitalized patients with intra-abdominal infections (IAIs) (n=3052) and urinary tract infections (UTIs) (n=1088) in 11 Asia-Pacific countries/regions from 2013 to 2015. Amikacin (98.3, 96.4 %), imipenem (97.1, 95.5 %) and ertapenem (95.3, 93.2 %) demonstrated the highest rates of susceptibility for isolates of K. pneumoniae from IAI and UTI, respectively, whereas susceptibility to advanced-generation cephalosporins was <84 and <71 %, respectively. K. pneumoniae with an extended-spectrum β-lactamase-positive phenotype were more common in UTI (27.1 %) than IAI (16.2 %). Imipenem and amikacin were the most active agents against extended-spectrum β-lactamase-positive K. pneumoniae from IAI (95.1, 91.8 %) and UTI (94.9, 92.3 %), respectively, whereas <54 % were susceptible to piperacillin-tazobactam. Against Enterobacter spp. and P. aeruginosa, amikacin demonstrated the highest rates of susceptibility for isolates from IAI (99.7, 95.5 %) and UTI (90.9, 91.5 %), respectively. K. pneumoniae, Enterobacter spp. and P. aeruginosa from urine demonstrated lower susceptibility to levofloxacin (74.1, 81.8 and 73.8 %) than from IAI (87.6, 91.8 and 85.4 %). For A. baumannii, rates of susceptibility to all agents tested were <43 %. We conclude that the studied Gram-negative ESKAPE pathogens demonstrated reduced susceptibility to commonly prescribed advanced-generation cephalosporins, piperacillin-tazobactam and levofloxacin, while amikacin and carbapenems were the most active. Ongoing surveillance to monitor evolving resistance trends and

  13. [Nonfermentative gram-negative bacteria: isolation rates and antibiotic sensitivity].

    PubMed

    Bogomolova, N S; Bol'shakov, L V; Kuznetsova, S M; Oreshkina, T D

    2010-01-01

    The isolation rates of nonfermentative gram-negative bacteria (NFGNB) are analyzed in the inpatients treated at the B. V. Petrovsky Russian Surgery Research Center in 2005-2009 and antibiotic resistance trends in nosocomial strains of NFGNB are traced in the above period. The study of the etiological structure of nosocomial infections has shown that the past 2 years (2008 and 2009) were marked by a clear tendency for the preponderance of gram-positive coccal pathogens (46.8 and 53.9%) with a considerable (1.5-2-fold) reduction in the proportion of representatives of enterobacteria (31.5 and 24.5%) and NFGB (13.4 and 11.3%), but with an increase in the proportion of fungi up to 7.1 and 8.6%, respectively. Among the NFGNBs, P. aeruginosa remains ohe of the most common pathogens for nosocomial infections although its portion in the number of all etiologically significant microorganisms was substantially reduced (from 13% in 2005 to 4.6% in 2009). It continues to remain one of the most common causative agents for infections of the urinary tract (e.g., after renal transplantation) and upper and lower respiratory tract (e.g. nosocomial pneumonia) and for those developing after surgical interventions (postoperative wound suppuration discharged along the drainages, from a T-sized tube, etc.). Among the NFGNBs, Acinetobacter spp. was the second frequently isolated pathogen, the isolation rate for which also decreased from 7.9% in 2005 to 2.6% in 2009. Polymyxin B and carbapenems (imipenem, meropenem, and doripenem) showed the highest activity against the vast majority of the test strains; however, there was an absolutely clear declining trend in the proportion of carbapenem-sensitive strains among virtually all the NFGNBs under study. According to the proportion of imipenem-, meropenem-, and doripenem-sensitive nosocomial P. aeroginosa strains (66.7, 46.6, and 44.7%, respectively), doripenem had the least activity. Acinetobacter spp. strains sensitive to these drugs showed

  14. Antibiotic Resistance Patterns of Gram-Negative Psychrotrophic Bacteria from Bulk Tank Milk.

    PubMed

    Decimo, Marilù; Silvetti, Tiziana; Brasca, Milena

    2016-04-01

    Bacterial resistance to antibiotics is a major global health problem and resistance of Pseudomonadaceae and Enterobacteriaceae is a serious concern. We investigated the prevalence of drug-resistance in a total of 80 psychrotrophic strains from bulk milk belonging to Pseudomonas genus (n. 63) and Enterobacteriaceae group (n. 17). All the strains were tested against 16 antibiotics. Pseudomonas were further investigated for their sensitivity against 12 additional antibiotics. Pseudomonas showed a high susceptibility toward fluoroquinolones, aminoglycosides, and piperacillin and, to a lesser extent, to imipenem, ceftazidime, cefepime. Thirty-five out of 63 Pseudomonas strains were susceptible to meropenem, while among antibiotics for which recommended breakpoints are not yet available, 55% of Pseudomonas strains had no inhibition halo in presence of nitrofurantoin, highlighting a resistance toward this drug. The results obtained in this study indicate a high efficiency of fluoroquinolones, chloramphenicol (94%), and kanamycin (76%) for Enterobacteriaceae while a high prevalence of resistant strains was found to ampicillin (13/17). Serratia marcescens is highly susceptible to fluoroquinolones, chloramphenicol, and kanamycin. Moreover, mupirocin seems to be the new antibiotic with the less efficacy for Enterobacteriaceae, with 41% of strains without halo, pointing out an important resistance. Further knowledge on resistance to known and new antibiotics among Pseudomonas species and Enterobacteriaceae of milk origin was acquired.

  15. [Pharmaco-economic evaluation of antibiotic therapy in a ward for infections diseases

    PubMed

    Sabbatani, S.; Cannella, B.; Fulgaro, C.; Pipitone, E.; Cesari, R.

    2000-01-01

    For all hospitalized patients admitted in the first six months of 1999, we recorded the data relative to antibiotic therapy (TA) administered, establishing the period of treatment in days and the dosage, including any variations during the period in question. We calculated the prescribed daily dose (PDD) and were thus able to establish the expense incurred in antibiotic therapy, comparing the real overall cost per product used. For all patients, the discharge diagnosis was reported, and the whole case-study was aggregated into homogeneous groups. PDD was compared with DDD (defined daily doses). The Pareto curve was used to highlight the antibiotics with higher overall cost. Besides cotrimoxazole, ceftriaxone and ciprofloxacin were the antibiotics most frequently prescribed, while ceftriaxone, imipenem-cilastatine and vancomycin were the antibiotics incurring the greatest expense. With reference to the average duration of the treatment cycle, ceftriaxone (9.75 dd) and ciprofloxacin tbl (6.75 dd) were the only antibiotics (in monotherapy) used for less than 10 treatment days. Special attention was paid to analysing the TA costs in treating pneumonia, which accounted for the highest percentage of cases (50 cases). Ceftriaxone, especially pulmonary infections, was the most commonly used drug. In hospitalized subjects treated who show good therapeutic response, we recommend early discharge and continuation of the therapy at home (switch therapy). This strategy will allow the patient to return to his/her family in good time, also thereby reducing hospital management costs.

  16. High prevalence of fecal carriage of extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae in a pediatric unit in Madagascar

    PubMed Central

    2010-01-01

    Background Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae have spread worldwide but there are few reports on carriage in hospitals in low-income countries. ESBL-producing Enterobacteriaceae (ESBL-PE) have been increasingly isolated from nosocomial infections in Antananarivo, Madagascar. Methods we conducted a prevalence survey in a pediatric unit from March to April 2008 Patient rectal swabs were sampled on the first and the last day of hospitalization. Medical staff and environment were also sampled. Rectal and environmental swabs were immediately plated onto Drigalski agar supplemented with 3 mg/liter of ceftriaxon. Results Fecal carriage was detected in 21.2% of 244 infants on admission and 57.1% of 154 on discharge, after more than 48 hours of hospitalization (p < 0.001). The species most frequently detected on admission were Escherichia coli and Klebsiella pneumoniae (36.9%), whereas, on discharge, K. pneumoniae was the species most frequently detected (52.7%). ESBL-associated resistances were related to trimethoprim-sulfamethoxazole (91.3%), gentamicin (76.1%), ciprofloxacin (50.0%), but not to amikacin and imipenem. The increased prevalence of carriage during hospitalization was related to standard antimicrobial therapy. Conclusion The significant emergence of multidrug-resistant enteric pathogens in Malagasy hospitals poses a serious health threat requiring the implementation of surveillance and control measures for nosocomial infections. PMID:20624313

  17. Klebsiella pneumoniae yfiRNB operon affects biofilm formation, polysaccharide production and drug susceptibility.

    PubMed

    Huertas, Mónica G; Zárate, Lina; Acosta, Iván C; Posada, Leonardo; Cruz, Diana P; Lozano, Marcela; Zambrano, María M

    2014-12-01

    Klebsiella pneumoniae is an opportunistic pathogen important in hospital-acquired infections, which are complicated by the rise of drug-resistant strains and the capacity of cells to adhere to surfaces and form biofilms. In this work, we carried out an analysis of the genes in the K. pneumoniae yfiRNB operon, previously implicated in biofilm formation. The results indicated that in addition to the previously reported effect on type 3 fimbriae expression, this operon also affected biofilm formation due to changes in cellulose as part of the extracellular matrix. Deletion of yfiR resulted in enhanced biofilm formation and an altered colony phenotype indicative of cellulose overproduction when grown on solid indicator media. Extraction of polysaccharides and treatment with cellulase were consistent with the presence of cellulose in biofilms. The enhanced cellulose production did not, however, correlate with virulence as assessed using a Caenorhabditis elegans assay. In addition, cells bearing mutations in genes of the yfiRNB operon varied with respect to the WT control in terms of susceptibility to the antibiotics amikacin, ciprofloxacin, imipenem and meropenem. These results indicated that the yfiRNB operon is implicated in the production of exopolysaccharides that alter cell surface characteristics and the capacity to form biofilms--a phenotype that does not necessarily correlate with properties related with survival, such as resistance to antibiotics.

  18. [ANTIBIOTIC SENSITIVITY/RESISTANCY OF MICROBIAL STRAINS, ISOLATED FROM PUERPERAS, NEWBORNS AND SAMPLES OF MATERNITY WARD ENVIRONMENT].

    PubMed

    Kobeshavidze, D D; Chikviladze, D; Gachechiladze, Kh; Mikeladze, M

    2016-03-01

    In this article, there are given data of microorganisms sensitivity/resistancy investigation, to different groups of antibiotics. Microorganisms where isolated from puerperas, newborns and samples of maternity ward environment. Investigation was performed in L.T.D. "Imedis Clinica". Detection of microorganisms sensitivity/resistancy to antibiotics was performed by use of two methods: method of disc diffusion and serial dilution on solid breeding substratum. It was determined that gram positive, as well as gram negative microorganisms had sufficiently high level of resistancy to some penicillines, aminoglycosides, macrolides. Some species of gram negative microorganisms had resistancy to lincomicin in 100% of cases. High level of sensitivity was revealed to such antibiotics as amicalin, amoxiclav, cefepim, ciprofloxacin. Gram negative microorganisms had high level of sensitivity to imipenem-cilastatin and meropenem. Performed investigation confirms necessity of microbiological monitoring in different clinics, because it is one of the most significant components of infection control. It gives opportunity to perform exact antibiotic prophylaxis and if necessary - rational antibiotic therapy.

  19. Isolation and antibiotic susceptibility of E. coli from urinary tract infections in a tertiary care hospital

    PubMed Central

    Sabir, Sumera; Ahmad Anjum, Aftab; Ijaz, Tayyaba; Asad Ali, Muhammad; ur Rehman Khan, Muti; Nawaz, Muhammad

    2014-01-01

    Objective: The study was conducted to isolate and determine the antibiotic resistance in E. coli from urinary tract infections in a tertiary care hospital, Lahore. Methods: Urine samples (n=500) were collected from patients with signs and symptoms of Urinary tract infections. Bacteria were isolated and identified by conventional biochemical profile. Antibiotic resistance pattern of E. coli against different antibiotic was determined by Kirby-Baur method. Results: Bacterial etiological agent was isolated from 402 samples with highest prevalence of E. coli (321, 80%) followed by Staphylococcus aureus (9.4%), Proteus species (5.4%) and Pseudomonas species (5.2%). The E. coli were highly resistant to penicillin (100%), amoxicillin (100%) and cefotaxime (89.7%), followed by intermediate level of resistance to ceftazidime (73.8%), cephradine (73.8%), tetracycline (69.4%), doxycycline (66.6%), augmentin (62.6%), gentamycin (59.8%), cefuroxime (58.2%), ciprofloxacin (54.2%), cefaclor (50%), aztreonam (44.8%), ceftriaxone (43.3%), imipenem (43.3%), and low level of resistance to streptomycin (30%), kanamycin (19.9%), tazocin (14%), amikacin (12.7%) and lowest to norfloxacin (11.2%). Out of 321 E. coli isolates, 261 (81%) were declared as multiple drug resistant and 5 (1.5%) were extensive drug resistant. Conclusion: It is concluded that most of the urinary tract infections in human are caused by multiple drug resistant E. coli. PMID:24772149

  20. High-level carbapenem-resistant OXA-48-producing Klebsiella pneumoniae with a novel OmpK36 variant and low-level, carbapenem-resistant, non-porin-deficient, OXA-181-producing Escherichia coli from Thailand.

    PubMed

    Lunha, Kamonwan; Chanawong, Aroonwadee; Lulitanond, Aroonlug; Wilailuckana, Chotechana; Charoensri, Nicha; Wonglakorn, Lumyai; Saenjamla, Pimjai; Chaimanee, Prajuab; Angkititrakul, Sunpetch; Chetchotisakd, Ploenchan

    2016-06-01

    Five blaOXA-48-like-carrying Enterobacteriaceae isolates collected from two Thai patients in December 2012 were characterized. Three Klebsiella pneumoniae isolates giving two different pulsed-field gel electrophoresis patterns and sequence types (ST11 and ST37) from patient 1 harbored blaOXA-48 locating on Tn1999.2, whereas two Escherichia coli isolates with the same pulsotype and ST5 from Patient 2 carried ISEcp1-associated blaOXA-181. One K. pneumoniae strain had blaSHV-12, blaDHA-1, qnrB, and qnrS, while another strain harbored blaCTX-M-15, qnrS and aac(6')-Ib-cr. The E. coli strain contained blaCTX-M-15, blaCMY-2, qnrS, and aac(6')-Ib-cr. Interestingly, the OXA-48 producers with a novel OmpK36 variant by a substitution of Gly to Asp in the L3 loop-borne PEFXG motif exhibited high-level resistance to ertapenem, imipenem, and meropenem. In contrast, the OXA-181 producer with non-porin-deficient background showed low-level resistance to ertapenem only. Both patients died because of either septic shock or pneumonia. This study showed the impact of OXA-48-like carbapenemases in porin-defective clinical isolate background, which may lead to serious therapeutic problems in the near future.

  1. High-level and novel mechanisms of carbapenem resistance in Gram-negative bacteria from tertiary hospitals in Nigeria.

    PubMed

    Ogbolu, D O; Webber, M A

    2014-05-01

    To determine the occurrence and molecular basis of carbapenem resistance in Gram-negative bacteria from tertiary hospitals in Nigeria, 182 non-duplicate Gram-negative bacterial isolates were investigated for antimicrobial susceptibility, presence of carbapenemases (tested phenotypically and genotypically), random amplified polymorphic DNA (RAPD) typing, plasmid sizing and replicon typing. Minimum inhibitory concentrations of carbapenems showed a high degree of resistance, with 67 isolates (36.8%) being resistant to all carbapenems, of which 40 (59.7%) produced enzymes able to hydrolyse imipenem. PCR and sequencing identified only 10 isolates (5.5%) carrying known carbapenemase genes, including bla(NDM), bla(VIM) and bla(GES). The majority of phenotypically carbapenem-resistant and carbapenemase-producing isolates did not carry a known carbapenemase gene. Transconjugant or transformant plasmid sizes were estimated to be 115 kb for bla(NDM)- and 93 kb for bla(VIM)-carrying plasmids. These plasmids were untypeable for replicon/incompatibility and transferred various other genes including plasmid-mediated quinolone resistance (PMQR) genes and bla(CTX-M-15). Typing showed that the isolates in this study were not clonally related. There is a high level of carbapenem resistance in Nigeria. As well as the globally relevant carbapenemases (bla(NDM), bla(VIM) and bla(GES)), there are other unknown gene(s) or variant(s) in circulation able to hydrolyse carbapenems and confer high-level resistance.

  2. Impact of Acinetobacter baumannii superoxide dismutase on motility, virulence, oxidative stress resistance and susceptibility to antibiotics.

    PubMed

    Heindorf, Magdalena; Kadari, Mahendar; Heider, Christine; Skiebe, Evelyn; Wilharm, Gottfried

    2014-01-01

    Acinetobacter baumannii is a Gram-negative bacterium appearing as an opportunistic pathogen in hospital settings. Superoxide dismutase (SOD) contributes to virulence in several pathogenic bacteria by detoxifying reactive oxygen species released in the course of host defense reactions. However, the biological role of SODs in A. baumannii has not yet been elucidated. Here, we inactivated in A. baumannii ATCC 17978 gene A1S_2343, encoding a putative SOD of the Fe-Mn type by transposon insertion, resulting in mutant ATCC 17978 sod2343::Km. The mutation was also introduced in two naturally competent A. baumannii isolates by transformation with chromosomal DNA derived from mutant ATCC 17978 sod2343::Km. We demonstrate that inactivation of sod2343 leads to significant motility defects in all three A. baumannii strains. The mutant strains were more susceptible to oxidative stress compared to their parental strains. Susceptibility to colistin and tetracycline was increased in all mutant strains while susceptibility of the mutants to gentamicin, levofloxacin and imipenem was strain-dependent. In the Galleria mellonella infection model the mutant strains were significantly attenuated. In conclusion, sod2343 plays an important role in motility, resistance to oxidative stress, susceptibility to antibiotics and virulence in A. baumannii.

  3. Impact of Acinetobacter baumannii Superoxide Dismutase on Motility, Virulence, Oxidative Stress Resistance and Susceptibility to Antibiotics

    PubMed Central

    Heider, Christine; Skiebe, Evelyn; Wilharm, Gottfried

    2014-01-01

    Acinetobacter baumannii is a Gram-negative bacterium appearing as an opportunistic pathogen in hospital settings. Superoxide dismutase (SOD) contributes to virulence in several pathogenic bacteria by detoxifying reactive oxygen species released in the course of host defense reactions. However, the biological role of SODs in A. baumannii has not yet been elucidated. Here, we inactivated in A. baumannii ATCC 17978 gene A1S_2343, encoding a putative SOD of the Fe-Mn type by transposon insertion, resulting in mutant ATCC 17978 sod2343::Km. The mutation was also introduced in two naturally competent A. baumannii isolates by transformation with chromosomal DNA derived from mutant ATCC 17978 sod2343::Km. We demonstrate that inactivation of sod2343 leads to significant motility defects in all three A. baumannii strains. The mutant strains were more susceptible to oxidative stress compared to their parental strains. Susceptibility to colistin and tetracycline was increased in all mutant strains while susceptibility of the mutants to gentamicin, levofloxacin and imipenem was strain-dependent. In the Galleria mellonella infection model the mutant strains were significantly attenuated. In conclusion, sod2343 plays an important role in motility, resistance to oxidative stress, susceptibility to antibiotics and virulence in A. baumannii. PMID:25000585

  4. Seasonal variation of Brazilian red propolis: Antibacterial activity, synergistic effect and phytochemical screening.

    PubMed

    Regueira, M S; Tintino, Saulo Relison; da Silva, Ana Raquel Pereira; Costa, Maria do Socorro; Boligon, Aline Augusti; Matias, Edinardo F F; de Queiroz Balbino, Valdir; Menezes, Irwin R A; Melo Coutinho, Henrique Douglas

    2017-03-27

    The aim of this study was to investigate the effect of the dry and rainy season on the antibacterial activity and chemical composition of the Brazilian red propolis. The samples were collected in rainy (RP-PER) and dry (RP-PED) seasons and analyzed by HPLC-DAD. The extracts were tested alone and in association with antibiotics against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. The HPLC analysis identified luteolin and quercetin as the main compounds. Seasonal variation was observed according to concentrations of the compounds. The MIC values against E. coli ranged from 128 μg/mL to 512 μg/mL (EC 06 and EC ATCC). The red propolis showed MIC values of 512 μg/mL against both strains of P. aeruginosa used in our study (PA03 and PA24) and against strains of Gram-positive bacteria S. aureus the MICs ranged from 64 μg/mL to ≥1024 μg/mL (SA10). A synergistic effect was observed when we combined the RP-PED with gentamicin against all the strains tested. When we combined the RP-PED with Imipenem, we only observed synergistic effect against P. aeruginosa. According to our synergistic activity results, the utilization of red propolis collected in the drier periods can be used as an adjuvant against multiresistant bacterial infections.

  5. Haemolytic differential identification of Arcanobacterium haemolyticum isolated from a patient with diabetic foot ulcers

    PubMed Central

    Kang, Hyesook; Park, Gyunam; Kim, Hyeran

    2016-01-01

    Introduction: Arcanobacterium haemolyticum (formerly known as Corynebacterium haemolyticum) is the causative agent of sore throat and also causes skin and soft tissue infections in diabetes patients. A. haemolyticum is a Gram-positive, catalase-negative, β-haemolytic bacillus. A. haemolyticum poses a diagnostic challenge in the hospital laboratory because most coryneform bacilli are considered as normal flora or contaminants, and it is therefore difficult to differentiate from β-haemolytic streptococci by colony characteristics. Case presentation: A. haemolyticum was isolated from a diabetic patient with foot ulcers and the isolate was identified by using a VITEK-2 system, CAMP inhibition test, reverse CAMP test and a 23S rRNA gene sequence analysis. The isolated A. haemolyticum inhibited haemolysis of Staphylococcus aureus in the CAMP test and enhanced haemolysis of Streptococcus agalactiae in the reverse CAMP test. The diabetic patient was treated with teicoplanin and imipenem, and the ulcers healed within 2 weeks. Conclusion: The present study suggests that a haemolytic differential method using the CAMP inhibition and reverse CAMP tests can be useful for differentiating A. haemolyticum from β-haemolytic streptococci. PMID:28348747

  6. Drug treatment of pneumonia in the hospital. What are the choices?

    PubMed

    Aoun, M; Klastersky, J

    1991-12-01

    Mortality and morbidity of nosocomial pneumonia remain high. Successful treatment of pulmonary infections depends on several factors including type of infection, offending pathogen, status of host defences, and adequate choice of antibiotic therapy. The physician's decision should aim at achieving antibiotic concentrations beyond the MIC at the site of infection. Gram-negative bacilli, notably Pseudomonos aeruginosa, Klebsiella pneumoniae and Escherichia coli, remain the most frequent agents in nosocomial pneumonia. Staphylococcus aureus and Streptococcus pneumoniae predominate among the Gram-positive cocci. Pneumocystis carinii predominates in immunocompromised patients. Protected sample bronchoscopy associated with quantitative cultures of samples, and quantification of intracellular microorganisms in cells recovered by broncho-alveolar lavage are two promising procedures which might replace previous, more aggressive methods. Penetration of antibiotics into lung tissue depends on physicochemical properties of the drug and the degree of inflammation of lung tissue. Quinolones, macrolides, tetracyclines and trimethoprim penetrate well into bronchial secretions. Penetration is moderate to low for aminoglycosides and beta-lactams. Fluoroquinolones and new beta-lactam agents, including third-generation cephalosporins imipenem, aztreonam and ticarcillin-clavulanate, showed comparative clinical efficacy in treatment of nosocomial pneumonia, with an efficacy rate close to 80%. Aminoglycosides should not be used alone. Combination therapy reduces but does not eliminate the risk of selection of Gram-negative resistant mutants. It should not be used routinely except for P. aeruginosa, Enterobacter cloacae and Serratia marcescens infections.

  7. Isolation and drug-resistant patterns of Campylobacter strains cultured from diarrheic children in Tehran.

    PubMed

    Feizabadi, Mohammad Mehdi; Dolatabadi, Samaneh; Zali, Mohammad Reza

    2007-07-01

    To detect campylobacteriosis and determine the drug susceptibility of causative organisms, we acquired 500 diarrheic samples in Cary-Blair transfer medium from two pediatric hospitals in Tehran between October 2004 and October 2005. The samples were also enriched in Preston broth (with supplements) and defibrinated sheep blood (7%). They were plated from both media on Brucella agar containing antibiotics and blood. Isolates were identified through biochemical tests and by the polymerase chain reaction method. Drug susceptibility testing was performed using the disk diffusion method. In total, 40 Campylobacter strains were isolated (8%). C. jejuni was the dominant species (85.8%) followed by C. coli (14.2%). The rates of resistance to antimicrobial agents were as follows: ciprofloxacin (61.7%), ceftazidime (47%), carbenicillin (35%), tetracycline (20.5%), cefotaxime (14.7%), ampicillin (11.7%), neomycin erythromycin and chloramphenicol (2.9%), gentamicin, streptomycin, imipenem and colistin (0.0%). Campylobacter is an important cause of diarrhea among Iranian children. The detection of Campylobacter increases by 25% if samples are treated in enrichment broth prior to plating. The high rate of resistance to ciprofloxacin is alarming, and further investigation into the possible reasons for this is imperative.

  8. [Evolution of use of antibiotics of restricted prescription and trend of bacterial susceptibility in Concepcion Regional Hospital, Chile].

    PubMed

    Morales, Felipe E; Villa, Lorenzo A; Fernández, Pola B; López, Mariela A; Mella, Sergio; Muñoz, Maritza

    2012-10-01

    The aim of this study was analyze the use of restricted antibiotics by patients hospitalized between 2004 and 2008 in Guillermo Grant Benavente Hospital in Concepcion. Also we attempted to identify possible correlations between antibiotic consumption and patterns of bacterial susceptibility. We performed a retrospective observational study that quantified the use of restricted antibiotics using DDD/100-bed-days, and cumulative susceptibility reports informed by the hospital's microbiology laboratory for bacterial susceptibility. The consumption of restricted antibiotics significantly increased between 2004 and 2008 (35%, p = 0.005). The groups with largest use were glycopeptides (37%) and carbapenems (30 %). These results can be explained by the emergence of endemic Methicillin-resistant Staphylococcus aureus (MRSA) and of Extended-spectrum beta-lactamase (ESBL) Gram negative bacilli. Results showed a decrease in susceptibility of P. aeruginosa to imipenem (p = 0.038) and K. pneumoniae to ciprofloxacin (p = 0.021). The total consumption of restricted antibiotic has significantly increased, especially among complex medical services. A significant decrease in bacterial susceptibility has been observed mainly in gram-negative bacilli. The monitoring of antimicrobial prescribing practices and local susceptibility patterns are essential to promote the rational use of antibiotics.

  9. Molecular epidemiology of carbapenem non-susceptible Acinetobacter baumannii in France.

    PubMed

    Jeannot, Katy; Diancourt, Laure; Vaux, Sophie; Thouverez, Michelle; Ribeiro, Amandina; Coignard, Bruno; Courvalin, Patrice; Brisse, Sylvain

    2014-01-01

    Carbapenem-resistant Acinetobacter baumannii have emerged globally. The objective of this study was to investigate the epidemiology, clonal diversity and resistance mechanisms of imipenem non-susceptible A. baumannii isolates in France. Between December 2010 and August 2011, 132 notifications were collected, including 37 outbreaks corresponding to 242 cases (2 to 55 per cluster). Multilocus sequence typing, pulsed-field gel electrophoresis (PFGE) and characterisation of carbapenemase-encoding genes were performed on 110 non-repetitive isolates. Gene blaOXA-23 was the most frequently detected (82%), followed by blaOXA-24 (11%) and blaOXA-58 (7%). Eleven sequence types (ST) were distinguished, among which sequence types ST1, ST2 (64%), ST20, ST25, ST85 and ST107. Isolates from epidemiological clusters had the same ST and resistance genes, indicating probable transmission within centres. In contrast, PFGE types of isolates differed among centres, arguing against transmission among centers. This study provides the first epidemiological snapshot of the population of A. baumannii with reduced susceptibility to carbapenems from France, and further underlines the predominance of international clones.

  10. Molecular Epidemiology of Carbapenem Non-Susceptible Acinetobacter baumannii in France

    PubMed Central

    Jeannot, Katy; Diancourt, Laure; Vaux, Sophie; Thouverez, Michelle; Ribeiro, Amandina; Coignard, Bruno; Courvalin, Patrice; Brisse, Sylvain

    2014-01-01

    Carbapenem-resistant Acinetobacter baumannii have emerged globally. The objective of this study was to investigate the epidemiology, clonal diversity and resistance mechanisms of imipenem non-susceptible A. baumannii isolates in France. Between December 2010 and August 2011, 132 notifications were collected, including 37 outbreaks corresponding to 242 cases (2 to 55 per cluster). Multilocus sequence typing, pulsed-field gel electrophoresis (PFGE) and characterisation of carbapenemase-encoding genes were performed on 110 non-repetitive isolates. Gene blaOXA-23 was the most frequently detected (82%), followed by blaOXA-24 (11%) and blaOXA-58 (7%). Eleven sequence types (ST) were distinguished, among which sequence types ST1, ST2 (64%), ST20, ST25, ST85 and ST107. Isolates from epidemiological clusters had the same ST and resistance genes, indicating probable transmission within centres. In contrast, PFGE types of isolates differed among centres, arguing against transmission among centers. This study provides the first epidemiological snapshot of the population of A. baumannii with reduced susceptibility to carbapenems from France, and further underlines the predominance of international clones. PMID:25517732

  11. Protective Effects of Cilastatin against Vancomycin-Induced Nephrotoxicity.

    PubMed

    Humanes, Blanca; Jado, Juan Carlos; Camaño, Sonia; López-Parra, Virginia; Torres, Ana María; Álvarez-Sala, Luís Antonio; Cercenado, Emilia; Tejedor, Alberto; Lázaro, Alberto

    2015-01-01

    Vancomycin is a very effective antibiotic for treatment of severe infections. However, its use in clinical practice is limited by nephrotoxicity. Cilastatin is a dehydropeptidase I inhibitor that acts on the brush border membrane of the proximal tubule to prevent accumulation of imipenem and toxicity. The aim of this study was to investigate the potential protective effect of cilastatin on vancomycin-induced apoptosis and toxicity in cultured renal proximal tubular epithelial cells (RPTECs). Porcine RPTECs were cultured in the presence of vancomycin with and without cilastatin. Vancomycin induced dose-dependent apoptosis in cultured RPTECs, with DNA fragmentation, cell detachment, and a significant decrease in mitochondrial activity. Cilastatin prevented apoptotic events and diminished the antiproliferative effect and severe morphological changes induced by vancomycin. Cilastatin also improved the long-term recovery and survival of RPTECs exposed to vancomycin and partially attenuated vancomycin uptake by RPTECs. On the other hand, cilastatin had no effects on vancomycin-induced necrosis or the bactericidal effect of the antibiotic. This study indicates that cilastatin protects against vancomycin-induced proximal tubule apoptosis and increases cell viability, without compromising the antimicrobial effect of vancomycin. The beneficial effect could be attributed, at least in part, to decreased accumulation of vancomycin in RPTECs.

  12. Transfer between an Algerian and a French hospital of four multi-drug resistant bacterial strains together via a single patient

    PubMed Central

    Moissenet, Didier; Richard, Patrick; Granados, Maria; Mérens, Audrey; Fournier, Damien; Fines-Guyon, Marguerite; Arlet, Guillaume; Vu-Thien, Hoang

    2015-01-01

    A 5 years-old girl, seriously burnt with fire, was first hospitalized during four days in an hospital at Alger, and then transferred to our hospital at Paris. Admitted in our intensive care burns unit, she was third degree burnt on 78% of total body surface area, already treated with imipenem and vancomycin at her arrival. Clinical aggravation was rapidly observed and death occurred within 24 hours. Cultures of blood and multiple wound swabs yielded 3 multi-drug resistant bacterial strains: Acinetobacter baumannii with carbapenemase OXA-23, Pseudomonas aeruginosa serotype O11 with metallo-ß-lactamase VIM-4 and Klebsiella pneumoniae with CTX-M-15 extended-spectrum ß-lactamase. Culture of a rectal swab showed colonization by Enterococcus faecium with vanA glycopeptides resistance. Patients colonized with one or two multi-drug-resistant strains were not rare in our burns unit, especially those transferred from Algeria, but this case of a single patient harboring four multi-drug-resistant strains is exceptional. PMID:26550534

  13. Multidrug resistant, extended spectrum β-lactamase (ESBL)-producing Escherichia coli isolated from a dairy farm.

    PubMed

    Ibrahim, Delveen R; Dodd, Christine E R; Stekel, Dov J; Ramsden, Stephen J; Hobman, Jon L

    2016-04-01

    Escherichia coli strains were isolated from a single dairy farm as a sentinel organism for the persistence of antibiotic resistance genes in the farm environment. Selective microbiological media were used to obtain 126 E. coli isolates from slurry and faeces samples from different farm areas. Antibiotic resistance profiling for 17 antibiotics (seven antibiotic classes) showed 57.9% of the isolates were resistant to between 3 and 15 antibiotics. The highest frequency of resistance was to ampicillin (56.3%), and the lowest to imipenem (1.6%), which appeared to be an unstable phenotype and was subsequently lost. Extended spectrum β-lactamase (ESBL) resistance was detected in 53 isolates and blaCTX-M, blaTEM and blaOXA genes were detected by PCR in 12, 4 and 2 strains, respectively. Phenotypically most isolates showing resistance to cephalosporins were AmpC rather than ESBL, a number of isolates having both activities. Phenotypic resistance patterns suggested co-acquisition of some resistance genes within subsets of the isolates. Genotyping using ERIC-PCR demonstrated these were not clonal, and therefore co-resistance may be associated with mobile genetic elements. These data show a snapshot of diverse resistance genes present in the E. coli population reservoir, including resistance to historically used antibiotics as well as cephalosporins in contemporary use.

  14. Medical Management for the Treatment of Nontuberculous Mycobacteria Infection of the Parotid Gland: Avoiding Surgery May Be Possible

    PubMed Central

    Bouhabel, Sarah; Oughton, Matthew Thomas

    2016-01-01

    Infection with nontuberculous mycobacteria (NTM) is uncommon in the head and neck; therefore there is no clear consensus on treating these infections. Our objective was to report our experience with a unique case of NTM infection of the parotid in an immunocompetent patient, in order to determine appropriate management through our experience with this pathology. A 57-year-old man, known for numerous comorbid diseases, presented to our institution complaining of right parotid swelling and pain. A computed tomography (CT) of the neck showed a multiloculated collection in the inferior portion of the right parotid gland, compatible with abscess formation. This abscess was drained by interventional radiology (IR) but required repeat drainage twice due to lack of initial improvement. He was treated with several antibiotics as culture results initially indicated Gram-positive bacilli and then Mycobacterium species, with final identification by a reference laboratory as Mycobacterium abscessus. Imipenem was initiated with amikacin and clarithromycin. His infection clinically and radiologically resolved after 5 months of antibiotherapy. In our case, the patient improved following intravenous antibiotic therapy. Our experience demonstrates that appropriate antibiotherapy can lead to resolution of Mycobacterium abscessus infection in the parotid without the risks associated with surgical intervention. PMID:27340407

  15. Prevalence of Genes of OXA-23 Carbapenemase and AdeABC Efflux Pump Associated with Multidrug Resistance of Acinetobacter baumannii Isolates in the ICU of a Comprehensive Hospital of Northwestern China.

    PubMed

    Jia, Wei; Li, Caiyun; Zhang, Haiyun; Li, Gang; Liu, Xiaoming; Wei, Jun

    2015-08-21

    The objective of this study was to explore the molecular epidemiology and the genetic support of clinical multidrug resistant (MDR) Acinetobacter baumannii (A. baumannii) isolates in an ICU ward of a comprehensive hospital. A total of 102 non-duplicate drug-resistant A. baumannii isolates were identified and 93 (91.1%) of them were MDR strains. Molecular analysis demonstrated that carbapenemase genes blaOXA-23 and blaOXA-51 were presented in all 93 MDR isolates (100%), but other carbapenemase genes, including blaOXA-24, blaOXA-58, blaIMP-1, blaIMP-4, blaSIM, and blaVIM genes were completely absent in all isolates. In addition, genes of AdeABC efflux system were detected in 88.2% (90/102) isolates. Interestingly, an addition to efflux pump inhibitor, reserpine could significantly enhance the susceptibility of MDR isolates to moxifloxacin, cefotaxime, and imipenem (p < 0.01). Clonal relationship analysis further grouped these clinical drug-resistant isolates into nine clusters, and the MDR strains were mainly in clusters A, B, C, and D, which include 16, 13, 25, and 15 isolates, respectively. This study demonstrated that clinical isolates carrying carbapenemase-encoding genes blaOXA-23 and AdeABC efflux pump genes are the main prevalent MDR A. baumannii, and the co-expression of oxacillinase and efflux pump proteins are thus considered to be the important reason for the prevalence of this organism in the ICU of this hospital.

  16. Characterisation of successive Acinetobacter baumannii isolates from a deceased haemophagocytic lymphohistiocytosis patient.

    PubMed

    Choi, Hyeon Jin; Kil, Min Cheol; Choi, Ji-Young; Kim, Sun Ju; Park, Ki-Sup; Kim, Yae-Jean; Ko, Kwan Soo

    2017-01-01

    In this study, 38 Acinetobacter baumannii isolates successively isolated from blood, skin swabs and tracheal aspirates from a single patient who died from haemophagocytic lymphohistiocytosis were investigated. The isolates were collected between March 2012 and August 2012. A. baumannii genotypes were determined by multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). In vitro antimicrobial susceptibility testing was performed and colistin heteroresistance and persistence were evaluated. The structure of AbaR resistance islands was explored, and serum sensitivity was determined. Based on MLST analysis, all 38 A. baumannii isolates showed the same sequence type (ST138). However, PFGE analysis showed that isolates from blood samples belonged to different genotypes depending on the isolation time: whilst blood isolates obtained at the early stages showed restriction patterns similar to those of isolates from other sources, isolates obtained at later stages exhibited a distinct pattern. All isolates were resistant to imipenem, cefepime, ciprofloxacin and piperacillin/tazobactam. Five isolates from tracheal aspirates and one from a skin swab were resistant to polymyxins, and two isolates from skin swabs and one from another source were non-susceptible to tigecycline. All colistin-susceptible isolates showed heteroresistance to colistin, and four were persisters. Isolates from blood showed higher survival rates against human serum than those from other sources. This study shows that the patient was infected with more than one A. baumannii strain. Heteroresistance, persistence or evasion of the innate immune response may explain the failure of antimicrobial treatments in this patient.

  17. Associated factors and outcomes for OXA-232 Carbapenem-resistant Enterobacteriaceae infections in a tertiary care centre in Mexico City: A case-control-control study.

    PubMed

    Torres-González, Pedro; Ortiz-Brizuela, Edgar; Cervera-Hernandez, Miguel Enrique; Bobadilla-Del Valle, Miriam; Martínez-Gamboa, Areli; Sifuentes-Osornio, José; Ponce-de-Leon, Alfredo

    2016-10-01

    We describe the outcomes and factors associated with OXA-232 producing carbapenem-resistant Enterobacteriaceae infections. A case-control-control study was performed; each case of infection by a carbapenem-resistant/OXA-232 (OXA-232-cases, n=27) was matched by isolation site, species, and date, with 2 cases of infection by carbapenem-susceptible/third-generation cephalosporin-susceptible (TGCS-controls, n=54) and 2 cases by carbapenem-susceptible/ESBL producing Enterobacteriaceae (ESBL-controls, n=54); 66% were urinary tract and 18.5% intra-abdominal infections. In the multivariable analysis with ESBL-controls, previous use β-lactam/β-lactamase antibiotics (OR 6.2; 95% CI 1.6-23.8) and, third-generation cephalosporins (OR 0.2; 95% CI 0.05-0.8) were associated with OXA-232 infection; with TGSC-controls previous use of β-lactam/β-lactamase antibiotics (OR 3.7; 95% 1.1-12.0) was associated. Among the OXA-232-cases, 29% received imipenem/cilastatin or meropenem, 11.1% ceftriaxone, 22.2% a carbapenem-based combination and 33.3% other antimicrobials as treatment. Previous β-lactam/β-lactamase antibiotics are associated with OXA-232 infections, and some may be treated with other active carbapenems or, in the absence of ESBL, third-generation cephalosporins.

  18. Bacterial etiology and antibiotic susceptibility pattern of diabetic foot infections in Tabriz, Iran.

    PubMed

    Akhi, Mohammad Taghi; Ghotaslou, Reza; Asgharzadeh, Mohammad; Varshochi, Mojtaba; Pirzadeh, Tahereh; Memar, Mohammad Yousef; Zahedi Bialvaei, Abed; Seifi Yarijan Sofla, Hasan; Alizadeh, Naser

    2015-01-01

    Zielsetzung: Es sollte die bakterielle Ätiologie (anaerobe und aerobe Flora) und Antibiotikaempfindlichkeit von Erregern beim diabetischen Fußsyndrom analysiert werden.Methode: Die Kultivierung erfolgte unter optimalen aeroben und anaeroben Bedingungen. Die Identifizierung der bakteriellen Isolate wurde mit mikrobiologischen Standardmethoden vorgenommen. Die Testung der Antibiotikaempfindlichkeit erfolgte gemäß den Richtlinien des Clinical und Laboratory Standards Instituts (CLSI).Ergebnisse: Von 60 Proben diabetischer Fußulcera wurden 92 Bakterienstämme isoliert. Dominierende Aerobier waren S. aureus (28%), gefolgt von Vertretern der Enterobacteriaceae (24%) einschließlich Escherichia coli (15%), Citrobacter spp. (4%), Enterobacter spp. (43%) und Coagulase-negativen Staphylococcus spp. (17%), Enterococcus spp. (15%), Pseudomonas aeroginosa (7%) und Acinetobacter spp. (4%). In den anaeroben Kulturen war in 4% der Ulcera Bacteroides fragilis nachweisbar, jedoch in keinem Fall Clostridium spp. Alle Gram-positiven Isolate waren gegen Linezolid empfindlich; alle Vertreter der Enterobacteriaceae waren gegenüber Imipenem empfindlich.Schlussfolgerung: Die meisten Infektionen bei den diabetischen Fußulcera waren durch eine Mischflora mit Dominanz von S. aureus und B. fragilis gekennzeichnet. Die Ulcera können daher in der Initialtherapie sinnvollerweise eine kombinierte antimikrobielle Therapie erfordern.

  19. Evaluation of antibiotic efficacy against infections caused by planktonic or biofilm cultures of Pseudomonas aeruginosa and Klebsiella pneumoniae in Galleria mellonella.

    PubMed

    Benthall, Gabriel; Touzel, Rebecca E; Hind, Charlotte K; Titball, Richard W; Sutton, J Mark; Thomas, Rachael J; Wand, Matthew E

    2015-11-01

    The lack of novel antibiotics for more than a decade has placed increased pressure on existing therapies to combat the emergence of multidrug-resistant (MDR) bacterial pathogens. This study evaluated the Galleria mellonella insect model in determining the efficacy of available antibiotics against planktonic and biofilm infections of MDR Pseudomonas aeruginosa and Klebsiella pneumoniae strains in comparison with in vitro minimum inhibitory concentration (MIC) determination. In general, in vitro analysis agreed with the G. mellonella studies, and susceptibility in Galleria identified different drug resistance mechanisms. However, the carbapenems tested appeared to perform better in vivo than in vitro, with meropenem and imipenem able to clear K. pneumoniae and P. aeruginosa infections with strains that had bla(NDM-1) and bla(VIM) carbapenemases. This study also established an implant model in G. mellonella to allow testing of antibiotic efficacy against biofilm-derived infections. A reduction in antibiotic efficacy of amikacin against K. pneumoniae and P. aeruginosa biofilms was observed compared with a planktonic infection. Ciprofloxacin was found to be less effective at clearing a P. aeruginosa biofilm infection compared with a planktonic infection, but no statistical difference was seen between K. pneumoniae biofilm and planktonic infections treated with this antibiotic (P>0.05). This study provides important information regarding the suitability of Galleria as a model for antibiotic efficacy testing both against planktonic and biofilm-derived MDR infections.

  20. Piscidin is Highly Active against Carbapenem-Resistant Acinetobacter baumannii and NDM-1-Producing Klebsiella pneumonia in a Systemic Septicaemia Infection Mouse Model

    PubMed Central

    Pan, Chieh-Yu; Chen, Jian-Chyi; Chen, Te-Li; Wu, Jen-Leih; Hui, Cho-Fat; Chen, Jyh-Yih

    2015-01-01

    This study was designed to investigate the antimicrobial activity of two synthetic antimicrobial peptides from an aquatic organism, tilapia piscidin 3 (TP3) and tilapia piscidin 4 (TP4), in vitro and in a murine sepsis model, as compared with ampicillin, tigecycline, and imipenem. Mice were infected with (NDM-1)-producing K. pneumonia and multi-drug resistant Acinetobacter baumannii, and subsequently treated with TP3, TP4, or antibiotics for different periods of time (up to 168 h). Mouse survival and bacterial colony forming units (CFU) in various organs were measured after each treatment. Toxicity was determined based on observation of behavior and measurement of biochemical parameters. TP3 and TP4 exhibited strong activity against K. pneumonia and A. baumannii in vitro. Administration of TP3 (150 μg/mouse) or TP4 (50 μg/mouse) 30 min after infection with K. pneumonia or A. baumannii significantly increased survival in mice. TP4 was more effective than tigecycline at reducing CFU counts in several organs. TP3 and TP4 were shown to be non-toxic, and did not affect mouse behavior. TP3 and TP4 are able at potentiate anti-Acinetobacter baumannii or anti-Klebsiella pneumonia drug activity, reduce bacterial load, and prevent drug resistance, indicating their potential for use in combating multidrug-resistant bacteria. PMID:25874924

  1. Complete Nucleotide Sequence of pGA45, a 140,698-bp IncFIIY Plasmid Encoding blaIMI-3-Mediated Carbapenem Resistance, from River Sediment

    PubMed Central

    Dang, Bingjun; Mao, Daqing; Luo, Yi

    2016-01-01

    Plasmid pGA45 was isolated from the sediments of Haihe River using Escherichia coli CV601 (gfp-tagged) as recipients and indigenous bacteria from sediment as donors. This plasmid confers reduced susceptibility to imipenem which belongs to carbapenem group. Plasmid pGA45 was fully sequenced on an Illumina HiSeq 2000 sequencing system. The complete sequence of plasmid pGA45 was 140,698 bp in length with an average G + C content of 52.03%. Sequence analysis shows that pGA45 belongs to IncFIIY group and harbors a backbone region which shares high homology and gene synteny to several other IncF plasmids including pNDM1_EC14653, pYDC644, pNDM-Ec1GN574, pRJF866, pKOX_NDM1, and pP10164-NDM. In addition to the backbone region, plasmid pGA45 harbors two notable features including one blaIMI-3-containing region and one type VI secretion system region. The blaIMI-3-containing region is responsible for bacteria carbapenem resistance and the type VI secretion system region is probably involved in bacteria virulence, respectively. Plasmid pGA45 represents the first complete nucleotide sequence of the blaIMI-harboring plasmid from environment sample and the sequencing of this plasmid provided insight into the architecture used for the dissemination of blaIMI carbapenemase genes. PMID:26941718

  2. In vivo protein interaction network analysis reveals porin-localized antibiotic inactivation in Acinetobacter baumannii strain AB5075.

    PubMed

    Wu, Xia; Chavez, Juan D; Schweppe, Devin K; Zheng, Chunxiang; Weisbrod, Chad R; Eng, Jimmy K; Murali, Ananya; Lee, Samuel A; Ramage, Elizabeth; Gallagher, Larry A; Kulasekara, Hemantha D; Edrozo, Mauna E; Kamischke, Cassandra N; Brittnacher, Mitchell J; Miller, Samuel I; Singh, Pradeep K; Manoil, Colin; Bruce, James E

    2016-11-11

    The nosocomial pathogen Acinetobacter baumannii is a frequent cause of hospital-acquired infections worldwide and is a challenge for treatment due to its evolved resistance to antibiotics, including carbapenems. Here, to gain insight on A. baumannii antibiotic resistance mechanisms, we analyse the protein interaction network of a multidrug-resistant A. baumannii clinical strain (AB5075). Using in vivo chemical cross-linking and mass spectrometry, we identify 2,068 non-redundant cross-linked peptide pairs containing 245 intra- and 398 inter-molecular interactions. Outer membrane proteins OmpA and YiaD, and carbapenemase Oxa-23 are hubs of the identified interaction network. Eighteen novel interactors of Oxa-23 are identified. Interactions of Oxa-23 with outer membrane porins OmpA and CarO are verified with co-immunoprecipitation analysis. Furthermore, transposon mutagenesis of oxa-23 or interactors of Oxa-23 demonstrates changes in meropenem or imipenem sensitivity in strain AB5075. These results provide a view of porin-localized antibiotic inactivation and increase understanding of bacterial antibiotic resistance mechanisms.

  3. Phylogenetic groups among Klebsiella pneumoniae isolates from Brazil: relationship with antimicrobial resistance and origin.

    PubMed

    de Melo, Maíra Espíndola Silva; Cabral, Adriane Borges; Maciel, Maria Amélia Vieira; da Silveira, Vera Magalhães; de Souza Lopes, Ana Catarina

    2011-05-01

    The objectives of this study were to determine the distribution of phylogenetic groups among Klebsiella pneumoniae isolates from Recife, Brazil and to assess the relationship between the groups and the isolation sites and resistance profile. Ninety four isolates of K. pneumoniae from hospital or community infections and from normal microbiota were analyzed by gyrA PCR-RFLP, antibiotic susceptibility, and adonitol fermentation. The results revealed the distinction of three phylogenetic groups, as it has also been reported in Europe, showing that these clusters are highly conserved within K. pneumoniae. Group KpI was dominantly represented by hospital and community isolates while groups KpII and KpIII displayed mainly normal microbiota isolates. The resistance to third generation cephalosporins, aztreonam, imipenem, amoxicillin/clavulanic acid, and streptomycin was only observed in KpI. The percentage of resistance was higher in KpI, followed by KpII and KpIII. The differences in the distribution of K. pneumoniae phylogenetic groups observed in this study suggest distinctive clinical and epidemiological characteristics among the three groups, which is important to understand the epidemiology of infections caused by this organism. This is the first study in Brazil on K. pneumoniae isolates from normal microbiota and community infections regarding the distribution of phylogenetic groups based on the gyrA gene.

  4. First Description of the Extended Spectrum-Beta-Lactamase Gene blaCTX-M-109 in Salmonella Grumpensis Strains Isolated from Neonatal Nosocomial Infections in Dakar, Senegal

    PubMed Central

    Seck, Abdoulaye; Dia, Mouhamadou Lamine; Timbiné, Lassina Gadi; Niang, Aïssatou Ameth; Ndiaye, El Hadji Momar; Sonko, Mouhamadou Abdoulaye; Wane, Abdoul Aziz; Bercion, Raymond; Ndiaye, Ousmane; Cissé, Moussa Fafa; Gassama-Sow, Amy

    2016-01-01

    Nosocomial infections are very common in African hospitals, particularly in neonatal units. These infections are most often caused by bacteria such as Escherichia coli, Klebsiella spp and Staphylococcus spp. Salmonella strains are rarely involved in nosocomial infections. Here, we report the first description of S. Grumpensis in neonatal infections in Senegal. Seventeen Salmonella strains were isolated from hospitalized infants’ stool samples. The following resistance phenotype was described in strains: AMXRTICRCFR FOXRCFXRCTXRCAZRIMPSATMRNARNORRCIPRTMRGMRTERSXTR. All isolates were susceptible to imipenem, 15 out of 17 produced an extended spectrum ß-lactamase (ESBL). blaOXA-1, blaSHV-1, blaTEM-1, blaCTX-M1 genes were detected in strains 8, 13, 5 and 8, respectively. blaCTX-M1 sequencing revealed the presence of blaCTX-M-109. Thirteen of the 17 Salmonella Grumpensis strains were analyzed by PFGE. These 13 isolates belonged to a single pulsotype and were genotypically identical. This is the first report of neonatal S. Grumpensis infections in Senegal, and the first report of blaCTX-M-109 in the genus Salmonella. PMID:27355480

  5. [Multicenter study on the monitoring of in vitro susceptibility to tigeeyeline in Santiago, Chile].

    PubMed

    García C, Patricia; Juliet L, Chrystal; Fernández V, Alejandra; San Martín S, Marcela; Cifuentes D, Marcela; Porte T, Lorena; Braun J, Stephanie; Castillo D, Loriana; Vechiola H, Maggie; Tapia P, Cecilia; Sakurada Z, Andrea; Chanqueo C, Leonardo; Lam E, Marusella; Espinoza P, Mónica; Curcio F, Daniel

    2009-06-01

    The objective of this multicenter study was to determine tigecycline susceptibility rates, measured by agar diffusion, in nine hospitals in Santiago and to compare these rates with other antimicrobials. Each center studied 20 strains per month. All intermediate and fully resistant strains as well as 10% of susceptibile strains were also studied by the broth microdilution method. Overall, 2301 strains were studied displaying the following susceptibility rates for tigecycline: 100% for Streptococcus sp, Enterococcus sp, and E. coli respectively, 99.8% for Staphylococcus sp, 93% for Klebsiella and 80% for Acinetobacter baumarmii. For Proteus, Providencia and Morganella the susceptibility rates were 4%. For cefotaxime-resistant Klebsiella and imipenem-resistant A. baumarmii susceptibility rates were 95% and 80% respectively. The agar diffusion and broth dilution method were 100% concordant for tigecycline susceptible strains but only 27% for resistant or intermediate strains represented mostly by Acinetobacter baumannii. The majority of these strains (57/59) proved to be susceptible after retesting. The great majority (96,6%) of strains tested from nine Chilean hospitals proved to be susceptible to tigecycline with exception for Proteus, Providencia and Morganella (66% resistance). Using the agar diffusion method for measuring tigecycline susceptibility to A. baumannii may be misleading.

  6. Antimicrobial susceptibility of vancomycin-resistant Leuconostoc, Pediococcus, and Lactobacillus species.

    PubMed Central

    Swenson, J M; Facklam, R R; Thornsberry, C

    1990-01-01

    Eighty-five strains of vancomycin-resistant gram-positive bacteria from three genera, Leuconostoc, Pediococcus, and Lactobacillus, were tested to determine susceptibility to 24 antimicrobial agents by broth microdilution and to 10 agents by disk diffusion. The MICs of vancomycin and teicoplanin ranged from 64 to greater than 512 micrograms/ml; however, the MICs of daptomycin, a new lipopeptide, were all less than or equal to 0.25 micrograms/ml. None of the organisms were resistant to imipenem, minocycline, chloramphenicol, gentamicin, or daptomycin. The MICs of penicillin were in the moderately susceptible range for all but three strains. Susceptibility to the other agents varied by genus and, in some cases, by species. When disk diffusion results were compared with MICs for drugs recommended for streptococci by the National Committee for Clinical Laboratory Standards, Villanova, Pa., few very major or major errors were obtained, but the number of minor errors was 19.3%. Therefore, we recommended that MIC testing be used instead of disk diffusion testing for these organisms. PMID:2344161

  7. Epidemiology and virulence of VIM-4 metallo-beta-lactamase-producing Pseudomonas aeruginosa isolated from burn patients in eastern Algeria.

    PubMed

    Meradji, Samah; Barguigua, Abouddihaj; Bentakouk, Mohamed Cherif; Nayme, Kaotar; Zerouali, Khalid; Mazouz, Dekhil; Chettibi, Houria; Timinouni, Mohammed

    2016-06-01

    In this study, we investigated the prevalence of carbapenem-resistant Pseudomonas aeruginosa (CRPA) in burn patients from eastern Algeria, CRPA virulence factors and the molecular epidemiology of CRPA. The overall prevalence of CRPA was 48.38%. Seven (46.66%) isolates were metallo-β-lactamases (MBL) producers and contained the MBL genes blaVIM-4 (n=6) and blaVIM-2 (n=1). Risk factors for CRPA infection were urinary catheter use and intubation (p=0.008). A high percentage of virulence factors (86.6% of these isolates were able to produce protease; 73.3% of isolates has DNase; and 66.6% were haemolysin positive) was observed in CRPA isolates. Among the seven MBL-producing isolates, four had the same clonal profile. The class 1 integrons, which contained the aadA7 gene cassette, were detected in six isolates. The 16SrRNA methylase gene, rmtB, was detected in one strain. All CRPA isolates were biofilm formers. A study on the kinetics of biofilm production revealed that biofilm production increased when the concentration of imipenem or ciprofloxacin and the incubation time increased. This is the first study to report the presence of VIM-4-producing P. aeruginosa from North Africa and also of the high prevalence of CRPA isolates. Based on our study of burn unit patients, the high percentage of P. aeruginosa with virulence factors and multi-drug resistance is alarming.

  8. Application of Bacteriophage-containing Aerosol against Nosocomial Transmission of Carbapenem-Resistant Acinetobacter baumannii in an Intensive Care Unit

    PubMed Central

    Ho, Yu-Huai; Tseng, Chun-Chieh; Wang, Lih-Shinn; Chen, Yi-Ting; Ho, Guan-Jin; Lin, Teng-Yi; Wang, Ling-Yi; Chen, Li-Kuang

    2016-01-01

    Background Carbapenem-resistant Acinetobacter baumannii (CRAB) is associated with nosocomial infections worldwide. Here, we used phage as a potential agent to evaluate the efficacy of daily cleaning practices combined with a bacteriophage-containing aerosol against CRAB. Methods A two-phase prospective intervention study was performed at a 945-bed public teaching hospital. From March to December 2013, we performed terminal cleaning using standard procedures plus an aerosol with active bacteriophage in the intensive care units to evaluate the impact on nosocomial incidence density, carbapenem-resistance rates and antimicrobial drug consumption amounts. Patients with culture proven CRAB infection were transferred to the isolation room when the phage aerosol cleaning had been completed. Results A total of 264 new acquisitions of CRAB were identified in the intensive care units (191 in the pre-intervention period and 73 in the intervention period). The rates of new acquisitions of CRAB in the intensive care units decreased from 8.57 per 1000 patient-days in the pre-intervention period to 5.11 per 1000 patient-days in the intervention period (p = 0.0029). The mean percentage of resistant isolates CRAB decreased from 87.76% to 46.07% in the intensive care units (p = 0.001). All of the antimicrobials showed a significant reduction in consumption except imipenem. Conclusions The bacteriophage was successful in decreasing the rates of infection caused by CRAB across intensive care units in a large teaching hospital. PMID:27992494

  9. Multi-antibiotic resistant bacteria in frozen food (ready to cook food) of animal origin sold in Dhaka, Bangladesh

    PubMed Central

    Sultana, Fouzia; Kamrunnahar; Afroz, Hafsa; Jahan, Afroz; Fakruddin, Md.; Datta, Suvamoy

    2014-01-01

    Objective To investigate the bacterial load and antibiotic resistance pattern of bacterial isolates obtained from (ready to cook) frozen food samples of animal origin in Dhaka, Bangladesh. Methods A total of 20 samples of frozen ready to cook food of animal origin were purchased from different separate grocery stores in Dhaka, Bangladesh. Bacteria were isolated and identified based on the basis of biochemical properties. Results A total of 57 isolates has been isolated from 20 samples, of them 35.08% were Gram positive and 64.92% were Gram negative organisms. Highest percentages of isolated organisms were Staphylococcocus spp. (24.56%), Alcaligene spp. (17.54%), Klebshiella spp. (12.28%) and the lowest percentages of organisms were Enterococcus spp., Actinobacillus spp. and Proteus spp. Antibiogram results clearly showed that levofloxacin and imipenem were the most effective drug against the isolates. The less effective antibiotics were chloramphenicol and nalidixic acid and resistance was highest against ciprofloxacin. The most contaminated food was chicken nuggets. Conclusions This type of frozen food contaminated with multi-antibiotic resistant microorganisms can be potential vehicles for transmitting food-borne diseases. PMID:25183094

  10. Antibiotic resistance and OXA-type carbapenemases-encoding genes in airborne Acinetobacter baumannii isolated from burn wards.

    PubMed

    Gao, Jing; Zhao, Xiaonan; Bao, Ying; Ma, Ruihua; Zhou, Yufa; Li, Xinxian; Chai, Tongjie; Cai, Yumei

    2014-03-01

    The study was conducted to investigate drug resistance, OXA-type carbapenemases-encoding genes and genetic diversity in airborne Acinetobacter baumannii (A. baumannii) in burn wards. Airborne A. baumannii were collected in burn wards and their corridors using Andersen 6-stage air sampler from January to June 2011. The isolates susceptibility to 13 commonly used antibiotics was examined according to the CLSI guidelines; OXA-type carbapenemases-encoding genes and molecular diversity of isolates were analyzed, respectively. A total of 16 non-repetitive A. baumannii were isolated, with 10 strains having a resistance rate of greater than 50% against the 13 antibiotics. The resistance rate against ceftriaxone, cyclophosvnamide, ciprofloxacin, and imipenem was 93.75% (15/16), but no isolate observed to be resistant to cefoperazone/sulbactam. Resistance gene analyses showed that all 16 isolates carried OXA-51, and 15 isolates carried OXA-23 except No.15; but OXA-24 and OXA-58 resistance genes not detected. The isolates were classified into 13 genotypes (A-M) according to repetitive extragenic palindromic sequence PCR (REP-PCR) results and only six isolates had a homology ≥90%. In conclusion, airborne A. baumannii in the burn wards had multidrug resistance and complex molecular diversity, and OXA-23 and OXA-51 were dominant mechanisms for resisting carbapenems.

  11. Activity of 10 antimicrobial agents against intracellular Rhodococcus equi.

    PubMed

    Giguère, Steeve; Berghaus, Londa J; Lee, Elise A

    2015-08-05

    Studies with facultative intracellular bacterial pathogens have shown that evaluation of the bactericidal activity of antimicrobial agents against intracellular bacteria is more closely associated with in vivo efficacy than traditional in vitro susceptibility testing. The objective of this study was to determine the relative activity of 10 antimicrobial agents against intracellular Rhodococcus equi. Equine monocyte-derived macrophages were infected with virulent R. equi and exposed to erythromycin, clarithromycin, azithromycin, rifampin, ceftiofur, gentamicin, enrofloxacin, vancomycin, imipenem, or doxycycline at concentrations achievable in plasma at clinically recommended dosages in foals. The number of intracellular R. equi was determined 48h after infection by counting colony forming units (CFUs). The number of R. equi CFUs in untreated control wells were significantly higher than those of monolayers treated with antimicrobial agents. Numbers of R. equi were significantly lower in monolayers treated with enrofloxacin followed by those treated with gentamicin, and vancomycin, when compared to monolayers treated with other antimicrobial agents. Numbers of R. equi in monolayers treated with doxycycline were significantly higher than those of monolayers treated with other antimicrobial agents. Differences in R. equi CFUs between monolayers treated with other antimicrobial agents were not statistically significant. Enrofloxacin, gentamicin, and vancomycin are the most active drugs in equine monocyte-derived macrophages infected with R. equi. Additional studies will be needed to determine if these findings correlate with in vivo efficacy.

  12. Activity of the investigational fluoroquinolone finafloxacin and seven other antimicrobial agents against 114 obligately anaerobic bacteria.

    PubMed

    Genzel, G H; Stubbings, W; Stîngu, C S; Labischinski, H; Schaumann, R

    2014-11-01

    The activity of finafloxacin against 73 strains of the Bacteroides fragilis group, 10 other Gram-negative anaerobic rods and 31 Clostridium difficile strains was determined by the broth microdilution technique. The activity was compared with that of moxifloxacin, levofloxacin, ciprofloxacin, clindamycin, imipenem, piperacillin/tazobactam and metronidazole. MIC(50/90) values (minimum inhibitory concentration, in μg/mL, at which 50% and 90% of the isolates tested are inhibited, respectively) for finafloxacin for the different species were determined: B. fragilis group, 0.5/2; other Gram-negative rods, 0.06/0.25; and C. difficile, 4/16. Furthermore, the MICs against 11 selected B. fragilis strains were determined under acidic conditions and resulted in MIC(50/90) values for finafloxacin of 0.25/4 μg/mL. Thus, finafloxacin shows promising activity against several pathogenic species of anaerobes. Furthermore, finafloxacin has increased activity against selected B. fragilis strains under acidic conditions compared with activity at neutral pH.

  13. Association between antimicrobial consumption and clinical isolates of methicillin-resistant Staphylococcus aureus: a 14-year study.

    PubMed

    Nakamura, Ayako; Miyake, Kazunori; Misawa, Shigeki; Kuno, Yutaka; Horii, Takashi; Hori, Satoshi; Kondo, Shigemi; Tabe, Yoko; Ohsaka, Akimichi

    2012-02-01

    The objective of this study was to determine the relationship between clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) and antimicrobial consumption in hospitalized patients over a 14-year period. The study was retrospectively conducted between January 1995 and December 2008 at Juntendo University Hospital, Tokyo, Japan, a 1,020-bed tertiary-care teaching hospital. The incidence of MRSA isolates was examined using clinical specimens presented to the microbiology laboratory in the hospital. Antimicrobial consumption through intravenous injection was calculated in terms of the number of defined daily doses per 100 bed-days. The correlation between the incidence of MRSA isolates and antimicrobial consumption was determined employing a multiple stepwise regression analysis. A total of 109,946 bacterial isolates were consecutively collected over the 14-year period, and, of these, 13,872 (64% of S. aureus strains excluding coagulase-negative staphylococci) were MRSA strains. The longitudinal observation showed that the number and rate of MRSA isolates marginally decreased. The rate of MRSA isolates among S. aureus strains in 1995 was 68.5%, whereas that in 2008 was 53.8%. Consumption of cephalosporins decreased. Among carbapenems, the rate of imipenem (IPM) consumption decreased, whereas that of meropenem increased. A multiple stepwise regression analysis revealed that the antimicrobial consumption of cefmetazole, cefotiam, and IPM was positively correlated with the incidence of MRSA isolates. The use of β-lactam antimicrobials may contribute to the development of MRSA strains.

  14. [Epidemiological features of multidrug resistant bacteria isolated from urine samples at the Mohammed V Military Teaching Hospital in Rabat, Morocco].

    PubMed

    Zohoun, A; Ngoh, E; Bajjou, T; Sekhsokh, Y; Elhamzaoui, S

    2010-08-01

    Hospital-acquired multidrug resistant bacteria infections are a serious public health issue causing increased morbidity, mortality and care cost. These risks underscore the need for health care institutions to maintain active panels to monitor, prevent, and manage hospital-acquired infections. The purpose of this study was to assess the epidemiology of urinary tract infection involving multidrug resistant bacteria at the Microbiology Laboratory of the Mohammed-V Military Teaching Hospital in Rabat. Study was carried out retrospectively on bacteria isolated from 10,243 urinary samples collected from January 1 to December 31, 2008. A total of 1,439 non-redundant bacteria (14.1%) meeting the criteria of urinary infection were identified. One hundred and three of the 1,439 bacteria isolated (7%) were multidrug resistant. Multidrug-resistant bacteria were more common in in-patients (63.1%). Mean patient age was 53.8 +/- 18.2 and the M/F sex ratio was 2.2. The most common multi-drug resistant bacteria were Enterobacteria producing extended spectrum bêta-lactamase (54.4% including 40.8% of Klebsiella pneumonia) and non-fermenting bacteria (45.6% including 26.2% of Pseudomonas aeruginosa. and 19.4% of Acinetobacter baumannii. These bacteria were resistant to the most commonly used antibiotics but remained highly sensitive to colistin, imipenem and amikacin.

  15. Prevalence, serovars, and antimicrobial susceptibility of Salmonella isolated from blue land crabs (Cardisoma guanhumi) in Grenada, West Indies.

    PubMed

    Peterson, Ross; Hariharan, Harry; Matthew, Vanessa; Chappell, Sam; Davies, Rob; Parker, Regina; Sharma, Andravindra

    2013-07-01

    Samples of intestine and hepatopancreas from 65 blue land crabs (Cardisoma guanhumi), a crustacean commonly consumed as a food item in Grenada, were collected from six geographic sites in Grenada and tested for Salmonella by enrichment and selective culture. The individual animal prevalence of Salmonella based on isolation was 17% (11 of 65), and all infected crabs were from three of the six sampled locations. Isolates were identified by serotyping as Salmonella enterica serovars Saintpaul (n = 6), Montevideo (n = 4), and Newport (n = 1). The intestines of all 11 infected crabs were positive for Salmonella, but only 7 of 11 hepatopancreas samples were positive for Salmonella, and these isolates were the same serovar as isolated from the matching intestine. These three Salmonella serovars are known to cause human illness in many countries, and in the Caribbean Salmonella Saintpaul has been frequently isolated from humans. In a disc diffusion assay, all isolates were susceptible to all 11 drugs tested: amoxicillin-clavulanic acid, ampicillin, cephalothin, chloramphenicol, ciprofloxacin, gentamicin, imipenem, neomycin, streptomycin, tetracycline, and trimethoprim-sulfamethoxazole. To our knowledge, this report is the first concerning isolation and antimicrobial susceptibilities of Salmonella serotypes from the blue land crab.

  16. Prevalence of Salmonella spp. in cane toads (Bufo marinus) from Grenada, West Indies, and their antimicrobial susceptibility.

    PubMed

    Drake, M; Amadi, V; Zieger, U; Johnson, R; Hariharan, H

    2013-09-01

    Cloacal swabs and caecal contents sampled from 58 cane toads (Bufo marinus) in St George's parish, Grenada, during a 7-month period in 2011 were examined by an enrichment and selective culture method for presence of Salmonella spp. Twenty-four (41%) toads were positive for Salmonella spp. of which eight were Salmonella enterica serovar Javiana, and eight were S. enterica serovar Rubislaw. The other serovars were as follows: Montevideo, 6; Arechavaleta, 1; and serovar: IV:43:-:-, 1. The high frequency of isolation of serovar Javiana, an emerging human pathogen associated with several outbreaks in the recent years in the eastern United States, suggests a possible role for cane toads in transmission of this serovar. Although S. Rubislaw has been isolated from lizards, bats and cases of some human infections, there is no report of its carriage by cane toads, and in such high frequency. The rate of carriage of S. Montevideo, a cause for human foodborne outbreaks around the world was also over 10% in the 58 toads sampled in this study. The antimicrobial drug susceptibility tests against amoxicillin-clavulanic acid, ampicillin, cefotaxime, ceftazidime, ciprofloxacin, enrofloxacin, gentamicin, imipenem, nalidixic acid, streptomycin, tetracycline and trimethoprim-sulfamethoxazole showed that drug resistance is minimal and is of little concern. Antimicrobial resistance was limited to ampicillin and amoxicillin-clavulanic acid in one isolate of S. Javiana and one isolate of S. Rubislaw. This is the first report of isolation and antimicrobial susceptibilities of various Salmonella serovars not identified previously in cane toads in Grenada, West Indies.

  17. In Vitro and In Vivo Efficacy of β-Lactams against Replicating and Slowly Growing/Nonreplicating Mycobacterium tuberculosis

    PubMed Central

    Dinesh, Neela; Shandil, Radha; Ramachandran, Vasanthi; Sharma, Sreevalli; Bhattacharjee, Deepa; Ganguly, Samit; Reddy, Jitendar; Ahuja, Vijaykamal; Panduga, Vijender; Parab, Manish; Vishwas, K. G.; Kumar, Naveen; Balganesh, Meenakshi; Balasubramanian, V.

    2013-01-01

    Beta-lactams, in combination with beta-lactamase inhibitors, are reported to have activity against Mycobacterium tuberculosis bacteria growing in broth, as well as inside the human macrophage. We tested representative beta-lactams belonging to 3 different classes for activity against replicating M. tuberculosis in broth and nonreplicating M. tuberculosis under hypoxia, as well as against streptomycin-starved M. tuberculosis strain 18b (ss18b) in the presence or absence of clavulanate. Most of the combinations showed bactericidal activity against replicating M. tuberculosis, with up to 200-fold improvement in potency in the presence of clavulanate. None of the combinations, including those containing meropenem, imipenem, and faropenem, killed M. tuberculosis under hypoxia. However, faropenem- and meropenem-containing combinations killed strain ss18b moderately. We tested the bactericidal activities of meropenem-clavulanate and amoxicillin-clavulanate combinations in the acute and chronic aerosol infection models of tuberculosis in BALB/c mice. Based on pharmacokinetic/pharmacodynamic indexes reported for beta-lactams against other bacterial pathogens, a cumulative percentage of a 24-h period that the drug concentration exceeds the MIC under steady-state pharmacokinetic conditions (%TMIC) of 20 to 40% was achieved in mice using a suitable dosing regimen. Both combinations showed marginal reduction in lung CFU compared to the late controls in the acute model, whereas both were inactive in the chronic model. PMID:23507276

  18. In vitro and in vivo efficacy of β-lactams against replicating and slowly growing/nonreplicating Mycobacterium tuberculosis.

    PubMed

    Solapure, Suresh; Dinesh, Neela; Shandil, Radha; Ramachandran, Vasanthi; Sharma, Sreevalli; Bhattacharjee, Deepa; Ganguly, Samit; Reddy, Jitendar; Ahuja, Vijaykamal; Panduga, Vijender; Parab, Manish; Vishwas, K G; Kumar, Naveen; Balganesh, Meenakshi; Balasubramanian, V

    2013-06-01

    Beta-lactams, in combination with beta-lactamase inhibitors, are reported to have activity against Mycobacterium tuberculosis bacteria growing in broth, as well as inside the human macrophage. We tested representative beta-lactams belonging to 3 different classes for activity against replicating M. tuberculosis in broth and nonreplicating M. tuberculosis under hypoxia, as well as against streptomycin-starved M. tuberculosis strain 18b (ss18b) in the presence or absence of clavulanate. Most of the combinations showed bactericidal activity against replicating M. tuberculosis, with up to 200-fold improvement in potency in the presence of clavulanate. None of the combinations, including those containing meropenem, imipenem, and faropenem, killed M. tuberculosis under hypoxia. However, faropenem- and meropenem-containing combinations killed strain ss18b moderately. We tested the bactericidal activities of meropenem-clavulanate and amoxicillin-clavulanate combinations in the acute and chronic aerosol infection models of tuberculosis in BALB/c mice. Based on pharmacokinetic/pharmacodynamic indexes reported for beta-lactams against other bacterial pathogens, a cumulative percentage of a 24-h period that the drug concentration exceeds the MIC under steady-state pharmacokinetic conditions (%TMIC) of 20 to 40% was achieved in mice using a suitable dosing regimen. Both combinations showed marginal reduction in lung CFU compared to the late controls in the acute model, whereas both were inactive in the chronic model.

  19. Hospital clonal dissemination of Enterobacter aerogenes producing carbapenemase KPC-2 in a Chinese teaching hospital.

    PubMed

    Qin, Xiaohua; Yang, Yang; Hu, Fupin; Zhu, Demei

    2014-02-01

    Carbapenems are first-line agents for the treatment of serious nosocomial infections caused by multidrug-resistant Enterobacteriaceae. However, resistance to carbapenems has increased dramatically among Enterobacteriaceae in our hospital. In this study, we report clonal dissemination caused by carbapenem-resistant Enterobacter aerogenes (CREA). In 2011, CREA was identified from 12 patients admitted to the neurosurgical ward. All 12 clinical isolates were non-susceptible to cefotaxime, ceftazidime, cefoxitin, ertapenem, imipenem or meropenem. All isolates carried the gene encoding Klebsiella pneumoniae carbapenemase-2 (KPC-2), except for the isolate E4. However, a remarkably lower expression level of the porin OmpF was detected in the non-KPC-2-producing isolate E4 on SDS-PAGE compared with the carbapenem-susceptible isolate. Epidemiological and molecular investigations showed that a single E. aerogenes strain (PFGE type A), including seven KPC-2-producing clinical isolates, was primarily responsible for the first isolation and subsequent dissemination. In a case-control study, we identified risk factors for infection/colonization with CREA. Mechanical ventilation, the changing of sickbeds and previous use of broad-spectrum antibiotics were identified as potential risk factors. Our findings suggest that further studies should focus on judicious use of available antibiotics, implementation of active antibiotic resistance surveillance and strict implementation of infection-control measures to avoid the rapid spread or clonal dissemination caused by carbapenem-resistant Enterobacteriaceae in healthcare facilities.

  20. In vitro and in vivo properties of a fully human IgG1 monoclonal antibody that combats multidrug resistant Pseudomonas aeruginosa.

    PubMed

    Adawi, Azmi; Bisignano, Carlo; Genovese, Tiziana; Filocamo, Angela; Khouri-Assi, Camellia; Neville, Anat; Feuerstein, Giora Z; Cuzzocrea, Salvatore; Neville, Lewis F

    2012-09-01

    The development of an anti-bacterial drug in the form of a monoclonal antibody (mAb) targeting an exposed virulence factor, represents an innovative therapeutic strategy. Consequently, a fully human IgG1 mAb (LST-007) targeting Pseudomonas aeruginosa (PA) flagellin type b was recombinantly expressed and characterized in vitro and in an infection model driven by a multidrug resistant (MDR) PA strain. LST-007 demonstrated a highly specific binding towards whole PA bacteria harboring flagellin type b and its recombinant counterpart, with a K(D) of 7.4x10(-10) M. In bioactivity assays, LST-007 or titers of Cmax sera derived from pharmacokinetic studies, markedly attenuated PA motility in an equipotent manner. In vivo, parenteral LST-007 (20 mg/kg) given as a single or double-dosing paradigm post-infection, afforded survival (up to 75% at Day 7) in a lethal model of pneumonia driven by the intratracheal (i.t.) instillation of an LD(80) of the MDR PA isolate. This protective effect was markedly superior to that of imipenem (30% survival at Day 7) and totally devoid with an irrelevant, human isotype mAb. These data lay credence that LST-007 may be a valuable adjunct to the limited list of anti-bacterials that can tackle MDR PA strains, thereby warranting its continued development for eventual clinical evaluation.

  1. Molecular analysis of typical and atypical enteropathogenic Escherichia coli (EPEC) isolated from children with diarrhoea.

    PubMed

    Nakhjavani, Farrokh Akbari; Emaneini, Mohammad; Hosseini, Hossein; Iman-Eini, Hossein; Aligholi, Marzieh; Jabalameli, Fereshteh; Haghi-Ashtiani, Mohammad Taghi; Taherikalani, Morovat; Mirsalehian, Akbar

    2013-02-01

    Diarrhoea continues to be one of the most common causes of morbidity and mortality among infants and children in developing countries. To investigate the incidence, antimicrobial resistance and genetic relationships of enteropathogenic Escherichia coli (EPEC) in children with diarrhoea, a total of 612 stool specimens were collected in Tehran, Iran, and cultured to isolate strains of EPEC. The disc diffusion method was used to determine the susceptibility of the isolates according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. The presence of eae, stx and bfp-A genes was determined by PCR. The genetic relationships between EPEC isolates were determined by pulsed-field gel electrophoresis (PFGE). Out of the 412 strains of E. coli obtained from 612 diarrhoeal stool specimens, 23 (5.6 %) were identified as EPEC, of which seven (30.4 %) were classified as typical strains of EPEC and 16 (69.6 %) were classified as atypical. Out of the 23 EPEC isolates, 69.5 % were resistant to ampicillin, 39.1 % were resistant to tetracycline and cotrimoxazole, 30.4 % were resistant to cefpodoxime, ceftazidime, ceftriaxone and aztreonam, and 26.1 % were resistant to imipenem. The isolates were classified into 21 pulsotypes by PFGE profiles. The present study shows that typical and atypical EPEC isolates displayed considerable heterogeneity in PFGE profiles and EPEC infections were only sporadic in Tehran. Overall 69 % of isolates were resistant to at least one of the antibiotics tested.

  2. Actinomycetoma and advances in its treatment.

    PubMed

    Welsh, Oliverio; Vera-Cabrera, Lucio; Welsh, Esperanza; Salinas, Mario Cesar

    2012-01-01

    Actinomycetoma is a chronic subcutaneous infection caused by aerobic branching actinomycetes. Its clinical features are firm tumefaction of the affected site and the presence of abscesses, nodules, and sinuses that drain a seropurulent exudate containing filamenting granules. The disease is caused by inoculation of the infectious agent through minor trauma in susceptible individuals. Nocardia brasiliensis, Actinomadura madurae, and Streptomyces somaliensis are among the most frequent agents in the Americas. Cellular and humoral immunity have been studied in animal models. Standard therapy for uncomplicated cases is sulfamethoxazole-trimethoprim given for many months. Bone involvement, disseminated cases, and special locations require combined treatment with amikacin and sulfamethoxazole-trimethoprim. Isolated reports include the addition of other antibiotics such as rifampicin, imipenem, or meropenem. When needed, other aminoglycosides can be used. Amoxicillin-clavulanic acid is indicated in specific cases as alternative treatment. Oxazolidinone antibiotics, such as linezolid and other similar compounds (DA-7218 and DA-7157), have been studied in experimental infections in animal models as well as in vitro and ex vivo, with encouraging results.

  3. Clinical characteristics and antimicrobial patterns in complicated intra-abdominal infections: a 6-year epidemiological study in southern China.

    PubMed

    Ouyang, Wenwei; Xue, Huiling; Chen, Yunqin; Gao, Weiguo; Li, Xiaoyan; Wei, Jia; Wen, Zehuai

    2016-03-01

    Complicated intra-abdominal infection (cIAIs) are a common and important cause of morbidity worldwide. In this study, the clinical features, microbiological profiles, antimicrobial patterns and treatments of 3233 cIAI patients (mean age, 47.6 years; 54.7% male) with 3531 hospitalisations from 2008-2013 were retrospectively investigated. The most commonly isolated bacteria were Escherichia coli (47.6%), Klebsiella pneumoniae (16.9%), Enterococcus faecalis (10.4%) and Pseudomonas aeruginosa (8.8%). Ciprofloxacin, aminoglycoside (gentamicin), piperacillin/tazobactam and carbapenems exhibited activity against 53%, 76%, 88% and 100% of extended-spectrum β-lactamase (ESBL)-positive Enterobacteriaceae isolates, respectively. Pseudomonas aeruginosa isolates exhibited 100%, 95%, 88%, 71% and 76% susceptibility to aminoglycoside (gentamicin), ciprofloxacin, meropenem, imipenem and ceftazidime, respectively, and Enterococcus remained 100% susceptible to vancomycin and linezolid. β-Lactam antibacterials other than penicillin (specifically third-generation cephalosporins) and imidazole derivatives (ornidazole and metronidazole) were the most common first-line treatments. Patients subjected to regimen change after initial antibiotic treatment had predisposing conditions (e.g. older age, more severe co-morbidities) and a higher incidence of P. aeruginosa infection; in addition, these patients encountered a higher average cost of care and worse clinical outcomes compared with those without medication modification. Taken together, these findings indicate the importance of appropriate initial empirical therapy and suggest the use of combination therapy comprising cephalosporins and metronidazole.

  4. [The sensitivity of anaerobic bacteria to chemotherapeutic agents (Zurich, 1991)].

    PubMed

    Wüst, J; Hardegger, U

    1991-12-27

    There have been numerous reports on resistance of anaerobic bacteria against antimicrobial agents. Therefore, to assess the situation in Zurich, 187 anaerobic strains of various bacterial genera, isolated from clinical specimens during winter 1990/91, were tested for their susceptibility to antimicrobial agents active against anaerobic bacteria. Besides the Bacteroides fragilis group, which is naturally resistant against penicillin, 30% of isolates of other Bacteroides species were also resistant against penicillin. In general, anaerobes have remained susceptible to cefoxitin, chloramphenicol, clindamycin, imipenem, the 5-nitroimidazoles (metronidazole, ornidazole) as well as combinations of beta-lactam antibiotics with beta-lactamase inhibitors (clavulanic acid, sulbactam and tazobactam). Because rare strains resistant against cefoxitin, clindamycin and beta-lactams plus beta-lactamase inhibitors can be found, at least isolates from specific clinical situations should be tested for antimicrobial susceptibility. These are strains isolated from patients with brain abscess, endocarditis, osteomyelitis, arthritis, infected implants and prosthesis as well as those from persisting or recurrent bacteremia. Because the agar diffusion test yields unreliable results, minimal inhibitory concentration should be determined. Maybe the new 'E test' or the spiral gradient procedure can be used after evaluation.

  5. Detection of the Most Common Microorganisms and Their Resistance against Anti-microbials in Intubated Patients in an ICU in Kerman, Iran

    PubMed Central

    Sarafzadeh, Farhad; Sohrevardi, SeyedMojtaba; Gharehghozli, Maryam; Ahmadinejad, Mehdi

    2010-01-01

    The purpose of this study was to determine the prevalence of anti-microbial resistance in intubated patients in intensive care unit (ICU) of Bahonar hospital in Kerman province, Iran during the year 2008. Tracheal samples were obtained from 111 intubated patients in the ICU by broncoalveolar lavage method. Amikacin, Ceftazidim and Imipenem were used to evaluate antibiotic susceptibility. For detecting anti-microbial susceptibility, minimum inhibitory concentration method were used. Colony counts equal or more than 104 microorganisms/mL were considered resistant. Overall we obtained positive tracheal cultures from 32 patients (29%) out of 111 intubated ones. The most common micro organisms isolated were Klebsiella (90.6%), Acinetobacter (28.1%) and Pseudomonas (21.9%). The results showed that the most common resistance was against to ceftazidim. The susceptibility of Klebsiellain tracheal cultures to the antibiotics was only 5%. E. coli in both sexes was 100% resistant to the tested antibiotics. In the ICU, There was a very big problem concerning antibiotic resistance. Most of the isolated microorganisms were resistant to both the old and the new antibiotics. It may be related to the inappropriate use of antibiotics, bacterial contamination of enteral feeding and infection transmission by medical staff or instruments. PMID:24381610

  6. Extended-spectrum β-lactamases producing Klebsiella pneumoniae isolated in two hospitals in Goiânia/Brazil: detection, prevalence, antimicrobial susceptibility and molecular typing.

    PubMed

    Dos Santos, Daniella Fabíola; Pimenta, Fabiana Cristina; Alves, Rodrigo; Montalvão, Edlaine Rodrigues; Dos Santos, Daniela Braz; do Carmo Filho, José Rodrigues

    2008-10-01

    This study was developed to evaluate the prevalence of extended-spectrum β-lactamases (ESBL) producing Klebsiella pneumoniae in two hospitals (A and B) in Goiânia, GO, Brazil. The antimicrobial susceptibility of the isolates was determined using the MicroScan WalkAway (Dade Behring, USA). Tests to evaluate the genetic correlation between the isolates were also performed. For the ESBL phenotypic test, the Double-disk diffusion (DD) method was used. The strains isolated in Hospital B were submitted to DNA analysis by pulsed-field gel electrophoresis (PFGE). The study showed high prevalence of ESBL-producing K. pneumoniae (25% in hospital A and 66.7% in hospital B), with high rates of antimicrobial resistance. The most active compound was imipenem (100% susceptibility in vitro). The PFGE test showed similiarity in five strains and variability in six strains.The high prevalence of ESBL-producing Klebsiella may be due to individual selection and to dissemination of a common strain.

  7. Pan-European longitudinal surveillance of antibiotic resistance among prevalent Clostridium difficile ribotypes.

    PubMed

    Freeman, J; Vernon, J; Morris, K; Nicholson, S; Todhunter, S; Longshaw, C; Wilcox, M H

    2015-03-01

    Clostridium difficile infection remains a major healthcare burden. Until the recent introduction of fidaxomicin, antimicrobial treatments were limited to metronidazole and vancomycin. The emergence of epidemic C. difficile PCR ribotype 027 and its potential link to decreased antibiotic susceptibility highlight the lack of large-scale antimicrobial susceptibility and epidemiological data available. We report results of epidemiological and antimicrobial susceptibility investigations of C. difficile isolates collected prior to fidaxomicin introduction, establishing important baseline data. Thirty-nine sites in 22 countries submitted a total of 953 C. difficile isolates for PCR ribotyping, toxin testing, and susceptibility testing to metronidazole, vancomycin, fidaxomicin, rifampicin, moxifloxacin, clindamycin, imipenem, chloramphenicol, and tigecycline. Ninety-nine known ribotypes were identified. Ribotypes 027, 014, 001/072, and 078 were most frequently isolated in line with previous European studies. There was no evidence of resistance to fidaxomicin, and reduced susceptibility to metronidazole and vancomycin was also scarce. Rifampicin, moxifloxacin, and clindamycin resistance (13%, 40%, and 50% of total isolates, respectively) were evident in multiple ribotypes. There was a significant correlation between lack of ribotype diversity and greater antimicrobial resistance (measured by cumulative resistance score). Well-known epidemic ribotypes 027 and 001/072 were associated with multiple antimicrobial resistance, but high levels of resistance were also observed, particularly in 018 and closely related emergent ribotype 356 in Italy. This raises the possibility of antimicrobial exposure as the underlying reason for their appearance, and highlights the need for ongoing epidemiological and antimicrobial resistance surveillance.

  8. A biosensing strategy for the rapid detection and classification of antibiotic resistance.

    PubMed

    Chen, Qun; Andersson, Anneli; Mecklenburg, Michael; Xie, Bin

    2015-11-15

    Antibiotic resistance (AR) poses an ever growing threat to global public health. Methods are urgently needed that simplify and accelerate the clinical detection and classification of AR. Here we describe a function-based antibiotic resistance assay (FARA) biosensing strategy. The scheme comprises three key components: i) FARA directly measures the thermal signal generated from the catalytic break-down of antibiotics by AR enzymes, ii) a sample specific AR profile is created by analyzing a panel of antibiotics which enhances informational content and iii) meta-analysis of the AR profile database to correlate profiles with diagnosis, treatments and outcomes. In order to test the ability of the scheme to identify and classify AR, two well-studied antibiotic resistance enzymes, penicillinase and metallo-beta-lactamase (MBL), were profiled using a panel of 5 antibiotics: penicillin G, penicillin V, ampicillin, oxacillin and imipenem. The results show that the profiles of the two enzymes could easily detect AR and differentially classified these enzymes. More importantly, both enzymes showed a significant and distinct secondary catalytic profile, which dramatically increases informational content. FARA profiles can be generated and analyzed in 1h. FARA is a fast, simple, cost effective alternative for detecting and classifying AR. FARA will speed up AR detection and classification will allow more accurate individualized treatment. This will reduce the spread of resistance and personalized treatments will improve patient outcomes. Other potential applications of FARA technology are discussed, including the possibility of developing an in vitro blood model for studying AR.

  9. Protective Effects of Cilastatin against Vancomycin-Induced Nephrotoxicity

    PubMed Central

    Humanes, Blanca; Jado, Juan Carlos; Camaño, Sonia; López-Parra, Virginia; Torres, Ana María; Álvarez-Sala, Luís Antonio; Cercenado, Emilia; Tejedor, Alberto; Lázaro, Alberto

    2015-01-01

    Vancomycin is a very effective antibiotic for treatment of severe infections. However, its use in clinical practice is limited by nephrotoxicity. Cilastatin is a dehydropeptidase I inhibitor that acts on the brush border membrane of the proximal tubule to prevent accumulation of imipenem and toxicity. The aim of this study was to investigate the potential protective effect of cilastatin on vancomycin-induced apoptosis and toxicity in cultured renal proximal tubular epithelial cells (RPTECs). Porcine RPTECs were cultured in the presence of vancomycin with and without cilastatin. Vancomycin induced dose-dependent apoptosis in cultured RPTECs, with DNA fragmentation, cell detachment, and a significant decrease in mitochondrial activity. Cilastatin prevented apoptotic events and diminished the antiproliferative effect and severe morphological changes induced by vancomycin. Cilastatin also improved the long-term recovery and survival of RPTECs exposed to vancomycin and partially attenuated vancomycin uptake by RPTECs. On the other hand, cilastatin had no effects on vancomycin-induced necrosis or the bactericidal effect of the antibiotic. This study indicates that cilastatin protects against vancomycin-induced proximal tubule apoptosis and increases cell viability, without compromising the antimicrobial effect of vancomycin. The beneficial effect could be attributed, at least in part, to decreased accumulation of vancomycin in RPTECs. PMID:26504822

  10. Infectious anastomotic pseudoaneurysm complicating renal allograft: case report and review of literature

    PubMed Central

    Chung, Marvin MT; Chan, Yiu Che; Law, Yuk; Cheng, Stephen WK

    2017-01-01

    Infectious anastomotic pseudoaneurysm complicating renal transplant is rare, but probably under-reported with <30 cases worldwide. We report a 45-year-old man with hypertension, diabetes mellitus and end stage renal failure, who had a renal transplant anastomosed to the right external iliac artery and vein. Postoperatively, he made a slow recovery with malaise and persistent vague right iliac fossa discomfort. Ultrasound scan 1 month postoperatively showed perinephric collection, and fluid culture grew Enterococcus faecium and Pseudomonas aeruginosa. He was started on vancomycin, daptomycin and colistin. MAG-3 scan also showed suboptimal function in the renal allograft. His symptoms persisted with fever, and blood culture yielded P. aeruginosa. Repeated ultrasound scan, and subsequent computed tomography scan a few weeks later, showed perinephric collection and a large, 3.8×3.5 cm pseudoaneurysm posteromedial to the graft kidney. He underwent emergency graft excision, together with resection of the pseudoaneurysm with in situ reversed great saphenous vein interposition graft, and made a good recovery on hemodialysis. The aneurysm wall grew P. aeruginosa, and he was put on imipenem and cilastatin (tienam), colistin, ciprofloxacin and daptomycin. To our knowledge, this is one of very few cases in the world’s literature in which a P. aeruginosa infectious anastomotic pseudoaneurysm developed after a renal allograft. PMID:28260939

  11. Azolylthioacetamide: A Highly Promising Scaffold for the Development of Metallo-β-lactamase Inhibitors

    PubMed Central

    2015-01-01

    A new scaffold, azolylthioacetamide, was constructed and assayed against metallo-β-lactamases (MβLs). The obtained molecules specifically inhibited MβL ImiS, and 1c was found to be the most potent inhibitor, with a Ki = 1.2 μM using imipenem as substrate. Structure–activity relationships reveal that the aromatic carboxyl improves inhibitory activity of the inhibitors, but the aliphatic carboxyl does not. Compounds 1c–d and 1h–i showed the best antibacterial activities against E. coli BL21(DE3) cells producing CcrA or ImiS, resulting in 32- and 8-fold reduction in MIC values, respectively; 1c and 1f–j resulted in a reduction in MIC against P. aeruginosa. Docking studies revealed that 1a, 1c, and 1d fit tightly into the substrate binding site of CphA as a proxy for ImiS with the aromatic carboxylate forming interactions with Lys224, the Zn(II) ion, the backbone of Asn233, and hydrophobic portions of the inhibitors aligning with hydrophobic patches of the protein surface. PMID:25893049

  12. Epidemiology of Neonatal Sepsis and Implicated Pathogens: A Study from Egypt.

    PubMed

    Shehab El-Din, Eman M Rabie; El-Sokkary, Mohamed M Adel; Bassiouny, Mohamed Reda; Hassan, Ramadan

    2015-01-01

    Prospective analytic study was conducted in NICUs of three Egyptian Neonatal Network (EGNN) participants in Mansoura Hospitals in Egypt over a period of 18 months from March 2011 to August 2012. By using EGNN 28-day discharge form, all demographic, clinical, and laboratory data were recorded and studied. During the study period, 357 neonates were diagnosed as suspected sepsis with an incidence of 45.9% (357/778) among the admitted neonates at the three neonatal intensive care units. 344 neonates (sex ratio = 1.3:1) were enrolled in the study in which 152 (44.2%) were classified as early onset sepsis EOS (≤72 hr) and 192 (55.8%) as late onset sepsis LOS (>72 hr). Among the LOS cases, 33.9% (65/192) were caused by nosocomial infections. In 40.7% (140/344), sepsis was confirmed by positive blood culture. The total mortality rate for the proven neonatal sepsis was 51% (25/49) and 42.9% (39/91) for EOS and LOS, respectively. Coagulase negative staphylococci were predominant isolates in both EOS and LOS, followed by Klebsiella pneumoniae. Most of the bacterial isolates had low sensitivity to the commonly used empiric antibiotics. However, 70.1% (89/127) exhibited multidrug resistance. Best sensitivities among Gram-positive isolates were found against imipenem, ciprofloxacin, vancomycin, and amikacin.

  13. Combating bacterial resistance in skin and skin-structure infection: importance of beta-lactamase inhibition.

    PubMed

    Chan, J C

    1999-01-01

    Serious skin and skin-structure infections may require parenteral antibiotic therapy. Such infections are generally polymicrobial, and they often involve both gram-positive and gram-negative aerobes as well as anaerobic bacteria. Effective treatment thus requires the use of a broad-spectrum antibiotic or combination therapy. The development of antibiotic resistance by clinically important pathogens has significantly increased the difficulty of treating skin and skin-structure infections. One of the major mechanisms of resistance observed in organisms likely to be associated with such infections is the development of beta-lactamases that inactivate beta-lactam antibiotics. Two approaches have been taken to combat this problem: the use of beta-lactam/beta-lactamase inhibitor combinations and the development of beta-lactamase-stable drugs. Both strategies have resulted in treatments that are clinically and bacteriologically effective in patients with skin and skin-structure infections. The use of one beta-lactam/beta-lactamase inhibitor combination, ampicillin/sulbactam, has been demonstrated to be more cost-effective than treatment with beta-lactamase-stable antibiotics, such as cefoxitin and imipenem/cilastatin, for this indication.

  14. A Novel Extended-Spectrum β-Lactamase, SGM-1, from an Environmental Isolate of Sphingobium sp.

    PubMed Central

    Lamoureaux, Toni L.; Vakulenko, Viktoria; Toth, Marta; Frase, Hilary

    2013-01-01

    SGM-1 is a novel class A β-lactamase from an environmental isolate of Sphingobium sp. containing all of the distinct amino acid motifs of class A β-lactamases. It shares 77 to 80% amino acid sequence identity with putative β-lactamases that are present on the chromosome of all Sphingobium species whose genomes were sequenced and annotated. Thus, SGM-type β-lactamases are native to this genus. Antibiotic susceptibility testing classifies SGM-1 as an extended-spectrum β-lactamase, conferring the highest level of resistance to penicillins. Although SGM-1 contains the conserved cysteine residues characteristic of class A carbapenemases, it does not confer resistance to the carbapenem antibiotics imipenem, meropenem, or doripenem but does increase the MIC of ertapenem 8-fold. SGM-1 hydrolyzes penicillins and the monobactam aztreonam with similar catalytic efficiencies, ranging from 105 to 106 M−1 s−1. The catalytic efficiencies of SGM-1 for cefoxitin and ceftazidime were the lowest (102 to 103 M−1 s−1) among the cephalosporins tested, while the catalytic efficiencies against all other cephalosporins varied from about 105 to 106 M−1 s−1. SGM-1 exhibited measurable but not significant activity toward the carbapenems tested. SGM-1 also showed high affinity for clavulanic acid, tazobactam, and sulbactam (Ki < 1 μM); however, only clavulanic acid significantly reduced the MICs of β-lactams. PMID:23716045

  15. The Nonantibiotic Small Molecule Cyslabdan Enhances the Potency of β-Lactams against MRSA by Inhibiting Pentaglycine Interpeptide Bridge Synthesis

    PubMed Central

    Koyama, Nobuhiro; Tokura, Yuriko; Münch, Daniela; Sahl, Hans-Georg; Schneider, Tanja; Shibagaki, Yoshio; Ikeda, Haruo; Tomoda, Hiroshi

    2012-01-01

    The nonantibiotic small molecule cyslabdan, a labdan-type diterpene produced by Streptomyces sp. K04-0144, markedly potentiated the activity of the β-lactam drug imipenem against methicillin-resistant Staphylococcus aureus (MRSA). To study the mechanism of action of cyslabdan, the proteins that bind to cyslabdan were investigated in an MRSA lysate, which led to the identification of FemA, which is involved in the synthesis of the pentaglycine interpeptide bridge of the peptidoglycan of MRSA. Furthermore, binding assay of cyslabdan to FemB and FemX with the function similar to FemA revealed that cyslabdan had an affinity for FemB but not FemX. In an enzyme-based assay, cyslabdan inhibited FemA activity, where as did not affected FemX and FemB activities. Nonglycyl and monoglycyl murein monomers were accumulated by cyslabdan in the peptidoglycan of MRSA cell walls. These findings indicated that cyslabdan primarily inhibits FemA, thereby suppressing pentaglycine interpeptide bridge synthesis. This protein is a key factor in the determination of β-lactam resistance in MRSA, and our findings provide a new strategy for combating MRSA. PMID:23166602

  16. Modified CHROMagar Acinetobacter Medium for Direct Detection of Multidrug-Resistant Acinetobacter Strains in Nasal and Rectal Swab Samples

    PubMed Central

    Lee, Jacob; Kim, Taek-Kyung; Park, Min-Jeong; Kim, Han-Sung; Kim, Jae-Seok

    2013-01-01

    This study aimed to investigate whether CHROMagar Acinetobacter medium (CHROMagar, France) in combination with an antimicrobial supplement (modified CHROMagar Acinetobacter; CHROMagar, France) can be used for detecting and isolating multidrug-resistant Acinetobacter species (MRA) in nasal and rectal surveillance cultures. Nasal and rectal swab samples were collected from patients in an intensive care unit at a teaching hospital. The samples were used to inoculate modified CHROMagar Acinetobacter plates, which were examined after 24 and 48 hr of incubation at 37℃. Their susceptibility against the antimicrobial agents meropenem, imipenem, ciprofloxacin, and amikacin was analyzed using the Etest (bioMerieux, France). A total of 406 paired samples (406 nasal swabs and 406 rectal swabs) were obtained from 226 patients, and 120 samples (28 nasal and 28 rectal cultures, 47 nasal cultures only, and 17 rectal cultures only) yielded MRA. Seventy-five MRA isolates (18.5%) were recovered from the 406 nasal samples, and 45 MRA isolates (11.1%) were recovered from the 406 rectal samples. Of the 120 MRA isolates, 3 (2.5%) were detected only after 48 hr of incubation. The use of modified CHROMagar Acinetobacter together with nasal and rectal swabs and 1-day incubation is an effective surveillance tool for detecting MRA colonization. PMID:23667846

  17. Common antimicrobial resistance patterns, biotypes and serotypes found among Pseudomonas aeruginosa isolates from patient's stools and drinking water sources in Jordan.

    PubMed

    Shehabi, A A; Masoud, H; Maslamani, F A Balkam

    2005-04-01

    Pseudomonas aeruginosa was isolated in low rates from stool specimens of outpatients and inpatients (7% versus 12%) but in higher rates from chlorinated and nonchlorinated water sources (15% versus 44%), respectively in Jordan. The same biotype was recognized among 90% of P. aeruginosa isolates from patient's stools and water sources using specific biochemical profiles. Three serogroups belonging to 01, 06 and 011 accounted for the majority of these isolates in water (66%) and stools (78%), respectively. All P. aeruginosa isolates from water were highly susceptible (87%-100%) to piperacillin-tazobactam, amikacin, gentamicin, imipenem, aztreonam, ceftazidime and ciprofloxacin, whereas the isolates from stool were slightly less susceptible (81%-98%) to these antimicrobials. P. aeruginosa isolates from water and stool sources were almost equally highly resistant to tetracycline (86%-89%) and carbenicillin (88%-89%), respectively. One common small plasmid (15.4 kb) was detected in 14/25 (56%) of multidrug-resistant P. aeruginosa isolates from both water and stool. This study demonstrates certain common epidemiological characteristics including antimicrobial resistance pattern, biotypes and serotypes among P. aeruginosa isolates from patient's stools and drinking water sources in Jordan.

  18. Bacteriocins in S. mutans strains isolated from children with and without dental caries: biotypes and sensitivity to antibiotics.

    PubMed

    Gamboa, Fredy; Chaves, Margarita; Estupiñan, Mabel; Galindo, Adriana

    2008-01-01

    The aim of this study was to determine the production of bacteriocins in the Streptococcus mutans strains isolated from children with and without dental caries. With this purpose the dmft index was determined and non-stimulated saliva was collected from 53 3- to 5-year-old children. The samples were cultured on Mitis Salivarius Bacitracin agar and incubated anaerobically for two days at 37 degrees C. The isolates were biotyped using the Api-ZYM enzymatic system (bioMérieux; Marcy-lE'toile, France). Bacteriocin was detected using the double layer onto brain heart infusion agar technique and the minimal inhibitory concentrations of the isolates were evaluated against penicillin, amoxycillin, cefazolin, erythromycin, clindamycin, imipenem and vancomycin using an agar dilution method. The dental caries experience in these children was 66% (35/53) and dmft index average was 3.2 (range 2-6). S. mutans was found in the saliva of 33 children (62%). In the 33 strains of S. mutans, 10 biotypes were found. Eight (24%) of the 33 strains evaluated produced bacteriocins, 6 of these strains came from patients with dental caries and the other two from patients without dental caries. All isolates were highly sensitive to the antibiotics tested.

  19. Enterobacteriaceae isolates carrying the New Delhi metallo-β-lactamase gene in Yemen.

    PubMed

    Gharout-Sait, Alima; Alsharapy, Samer-Ahmed; Brasme, Lucien; Touati, Abdelaziz; Kermas, Rachida; Bakour, Sofiane; Guillard, Thomas; de Champs, Christophe

    2014-10-01

    Ten carbapenem-resistant Enterobacteriaceae (eight Klebsiella pneumoniae isolates and two Enterobacter cloacae) isolates from Yemen were investigated using in vitro antimicrobial susceptibility testing, phenotypic carbapenemase detection, multilocus sequence typing (MLST) and replicon typing. Carbapenemase, extended-spectrum β-lactamase (ESBL) and plasmid-mediated quinolone resistance determinant genes were identified using PCR and sequencing. All of the 10 carbapenem-resistant Enterobacteriaceae were resistant to β-lactams, tobramycin, ciprofloxacin and cotrimoxazole. Imipenem, doripenem and meropenem MICs ranged from 2 to >32 mg l(-1) and ertapenem MICs ranged from 6 to >32 mg l(-1). All of the K. pneumoniae isolates showed ESBL activity in phenotypic tests. Genes encoding blaNDM were detected in all strains. All K. pneumoniae strains produced CTX-M-15 ESBL and SHV β-lactamases. TEM-1 β-lactamase was detected in seven isolates. Nine isolates were qnr positive including QnrB1, QnrA1 and QnrS1, and six isolates produced AAC-6'-Ib-cr. MLST identified five different sequence types (STs): ST1399, ST147, ST29, ST405 and ST340. Replicon typing showed the presence of IncFII1K plasmids in four transformants. To the best of our knowledge, this is the first report of NDM-1-producing Enterobacteriaceae isolates in Yemen.

  20. Comparative in vitro activity of tigecycline against bacteria recovered from clinical specimens in Latin America.

    PubMed

    Bantar, C; Curcio, D; Fernandez Canigia, L; García, P; Guzmán Blanco, M; Leal, A L

    2009-04-01

    The present study was performed to evaluate the in vitro activity of tigecycline in comparison to other agents against isolates recovered from patients hospitalized in latin American. Organisms were collected in 47 clinical laboratories from 4 countries of latin America between November 2005 and October 2006 and were tested by using disk diffusion method as described by the CLSI. A total of 7966 isolates were assessed. Tigecycline proved highly active against staphylococci and enterococci (>99% susceptibility). Imipenem was the most active agent against Escherichia coli (100% susceptibility), followed by tigecycline, 98.6% susceptibility. Resistance to cefotaxime in this species was 15.3%. Global tigecycline susceptibility of Klebsiella species was 90.2%, but the susceptibility rate was significantly slower in Venezuela (82%) than in Argentina, Colombia and Chile (93%) (p<0.01). Global cefotaxime resistance to Klebsiella spp. was 32.2% and carbapenem resistance was detected in all countries. By adopting a susceptible breakpoint >or =16mm, 91.3% of the Acinetobacter isolates proved susceptible to tigecycline. Results from the present study suggest that tigecycline may be a suitable option in latin America, a region where multidrug resistance seems to be a dramatic, increasing problem and new antimicrobial choices are urgently needed.

  1. Epidemiology and clinical features of Shewanella infection over an eight-year period.

    PubMed

    To, Kelvin K W; Wong, Samson S Y; Cheng, Vincent C C; Tang, Bone S F; Li, Iris W S; Chan, Jasper F W; Seto, Wai-Kay; Tse, Herman; Yuen, Kwok-Yung

    2010-10-01

    Shewanella is a rare human pathogen that can lead to fatal infections. However, clinical information about this bacterium remains scarce. In this study, we retrospectively reviewed all patients with laboratory isolates of Shewanella over an 8-y period to assess risk factors, clinical manifestations and outcome. Twenty-nine patients were identified. Shewanella was most commonly isolated from intra-abdominal specimens (48.2%), followed by skin and soft tissue specimens (27.6%), blood (13.8%) and sputum (10.3%). Malignancy, hepatobiliary disease and diabetes mellitus were common underlying diseases. The overall 30-day mortality rate was 20.6%. Shewanella was considered a definite causative pathogen in 7 patients, and a recurrent infection occurred in 2 patients. Colonization of the biliary tract was common. Among co-isolated pathogens, the enteric flora was most represented. All isolates were susceptible to ceftazidime and aminoglycosides, but 1 isolate was resistant to imipenem. In conclusion, Shewanella may become a colonizing bacterium, subsequently causing invasive diseases in patients with an underlying disease.

  2. Biochemical and Structural Characterization of the Subclass B1 Metallo-β-Lactamase VIM-4 ▿

    PubMed Central

    Lassaux, Patricia; Traoré, Daouda A. K.; Loisel, Elodie; Favier, Adrien; Docquier, Jean-Denis; Sohier, Jean Sébastien; Laurent, Clémentine; Bebrone, Carine; Frère, Jean-Marie; Ferrer, Jean-Luc; Galleni, Moreno

    2011-01-01

    The metallo-β-lactamase VIM-4, mainly found in Pseudomonas aeruginosa or Acinetobacter baumannii, was produced in Escherichia coli and characterized by biochemical and X-ray techniques. A detailed kinetic study performed in the presence of Zn2+ at concentrations ranging from 0.4 to 100 μM showed that VIM-4 exhibits a kinetic profile similar to the profiles of VIM-2 and VIM-1. However, VIM-4 is more active than VIM-1 against benzylpenicillin, cephalothin, nitrocefin, and imipenem and is less active than VIM-2 against ampicillin and meropenem. The crystal structure of the dizinc form of VIM-4 was solved at 1.9 Å. The sole difference between VIM-4 and VIM-1 is found at residue 228, which is Ser in VIM-1 and Arg in VIM-4. This substitution has a major impact on the VIM-4 catalytic efficiency compared to that of VIM-1. In contrast, the differences between VIM-2 and VIM-4 seem to be due to a different position of the flapping loop and two substitutions in loop 2. Study of the thermal stability and the activity of the holo- and apo-VIM-4 enzymes revealed that Zn2+ ions have a pronounced stabilizing effect on the enzyme and are necessary for preserving the structure. PMID:21149620

  3. Pseudomonas aeruginosa on vinyl-canvas inflatables and foam teaching aids in swimming pools.

    PubMed

    Schets, F M; van den Berg, H H J L; Baan, R; Lynch, G; de Roda Husman, A M

    2014-12-01

    Swimming pool-related Pseudomonas aeruginosa infections mainly result in folliculitis and otitis externa. P. aeruginosa forms biofilms on surfaces in the swimming pool environment. The presence of P. aeruginosa on inflatables and foam teaching aids in 24 public swimming pools in the Netherlands was studied. Samples (n = 230) were taken from 175 objects and analysed for P. aeruginosa by culture. Isolated P. aeruginosa were tested for antibiotic resistance by disk diffusion. P. aeruginosa was detected in 63 samples (27%), from 47 objects (27%) in 19 (79%) swimming pools. More vinyl-canvas objects (44%) than foam objects (20%) were contaminated, as were wet objects (43%) compared to dry objects (13%). Concentrations were variable, and on average higher on vinyl-canvas than on foam objects. Forty of 193 (21%) P. aeruginosa isolates from 11 different objects were (intermediate) resistant to one or more of 12 clinically relevant antibiotics, mostly to imipenem and aztreonam. The immediate risk of a P. aeruginosa infection from exposure to swimming pool objects seems limited, but the presence of P. aeruginosa on pool objects is unwanted and requires attention of pool managers and responsible authorities. Strict drying and cleaning policies are needed for infrequently used vinyl-canvas objects.

  4. Functional synergy of α-helical antimicrobial peptides and traditional antibiotics against Gram-negative and Gram-positive bacteria in vitro and in vivo.

    PubMed

    Feng, Q; Huang, Y; Chen, M; Li, G; Chen, Y

    2015-01-01

    In this study, the antimicrobial activities based on the synergistic effects of traditional antibiotics (imipenem, cefepime, levofloxacin hydrochloride and vancomycin) and antimicrobial peptides (AMPs; PL-5, PL-31, PL-32, PL-18, PL-29 and PL-26), alone or in combination, against three Gram-positive bacteria (Staphylococcus aureus, Streptococcus pneumoniae and Staphylococcus epidermidis) and three Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae) were investigated. In addition, the antimicrobial activity that was based on the synergistic effects of levofloxacin hydrochloride and PL-5 against Staphylococcus aureus in vivo was explored in a mouse infection model. Traditional antibiotics and AMPs showed significant synergistic effects on the antibacterial activities against the different Gram-positive and Gram-negative bacteria in vitro. A strong synergistic effect in the PL-5 and levofloxacin hydrochloride combination against Staphylococcus aureus was observed in the mouse infection model in vivo. The mechanism of synergistic action was due to the different targets of AMPs and traditional antibiotics. The combination of AMPs and traditional antibiotics can dramatically enhance antimicrobial activity and may help prevent or delay the emergence of antibiotic resistance. Thus, this combination therapy could be a promising approach to treat bacterial infections, particularly mixed infections and multi-antibiotic-resistant infections, in the clinics.

  5. [Importance of information from the Department of Clinical Laboratory in the treatment of infectious diseases--from the viewpoint of medical safety].

    PubMed

    Kondo, Shigemi; Miida, Takashi

    2012-10-01

    For the report of microbiological laboratory staff to be made more effective, developments of the entire support systems regarding hospital infection control are essential. Therefore, it should be carried out side by side with the development of a guideline support system, proper antibiotic use, a consultation system, as well as education and training of medical staff. As measures of the Department of Clinical Laboratory, antibiograms are conducted periodically and a blood culture report is taken as a 24-hour system. In addition, the blood culture report is transmitted to ensure that the attending physician performs activities according to the electronic medical records as well as through contact by telephone. In addition, the ICD reported during the day on behalf of the laboratory technician, at the stage of the first report, and the estimation of bacterial species and suggestions for additional testing were performed. For the measures described above, the current rate of two sets of blood cultures taken comprises over 90%. In addition, the use of carbapenems was reduced by half. As the result, the rate of imipenem-resistant Pseudomonas aeruginosa was reduced by about 40% in 2006 to 20% in 2010, and the development of multi-drug resistant bacteria was markedly reduced.

  6. Antibiotic Multiresistance Analysis of Mesophilic and Psychrotrophic Pseudomonas spp. Isolated from Goat and Lamb Slaughterhouse Surfaces throughout the Meat Production Process

    PubMed Central

    Lavilla Lerma, Leyre; Benomar, Nabil; Casado Muñoz, María del Carmen; Gálvez, Antonio

    2014-01-01

    The aim of this study was to investigate the phenotypic and genotypic antibiotic resistance profiles of pseudomonads isolated from surfaces of a goat and lamb slaughterhouse, which were representative of areas that are possible sources of meat contamination. Mesophilic (85 isolates) and psychrotrophic (37 isolates) pseudomonads identified at the species level generally were resistant to sulfamethoxazole, erythromycin, amoxicillin, ampicillin, chloramphenicol, trimethoprim, rifampin, and ceftazidime (especially mesophiles), as well as colistin and tetracycline (especially psychrotrophes). However, they generally were sensitive to ciprofloxacin, gentamicin, imipenem, and kanamycin regardless of species identity. Worryingly, in the present study, we found multidrug resistance (MDR) to up to 13 antibiotics, which was related to intrinsic and acquired resistance mechanisms. Furthermore, a link between various antimicrobial resistance genes was shown for beta-lactams and tetracycline, trimethoprim, and sulfonamides. The distribution and resistome-based analysis of MDR pseudomonads in different slaughterhouse zones indicated that the main sources of the identical or related pseudomonad strains were the animals (feet and wool) and the slaughterhouse environment, being disseminated from the beginning, or entrance environment, to the environment of the finished meat products. Those facts must be taken into consideration to avoid cross-contamination with the subsequent flow of mobile resistance determinants throughout all slaughterhouse zones and then to humans and the environment by the application of adequate practices of hygiene and disinfection measures, including those for animal wool and feet and also the entrance environment. PMID:25172860

  7. High prevalence of multidrug-resistant Escherichia coli and Enterococcus spp. in river water, upstream and downstream of a wastewater treatment plant.

    PubMed

    Bessa, Lucinda J; Barbosa-Vasconcelos, Ana; Mendes, Angelo; Vaz-Pires, Paulo; Martins da Costa, Paulo

    2014-09-01

    In this study, microbial quality and antimicrobial resistance of faecal bacteria from a Portuguese river were assessed. River water samples collected upstream and downstream of a wastewater treatment plant, throughout a 3-month period, were used for the enumeration of Escherichia coli and Enterococcus spp. The highest numbers found for E. coli and enterococci were 1.1 × 10⁴ and 1.2 × 10⁴ colony forming units (CFU)/100 ml, respectively. In total, 144 isolates of E. coli and 144 of enterococci were recovered and tested for antimicrobial susceptibility; 104 E. coli and 78 Enterococcus spp. showed resistance to one or more antimicrobial drugs. Overall, 70 and 32 different resistance patterns were found for E. coli and enterococci, respectively. One E. coli showed resistance to imipenem and 29 isolates were extended spectrum β-lactamase-producers. Multidrug-resistant E. coli belonged mostly to groups A, B1 and group D. Enterococcus spp. were mostly resistant to rifampicin, tetracycline, azithromycin and erythromycin; six isolates showed resistance to vancomycin, presenting the VanA phenotype. The high levels of E. coli and enterococci and the remarkable variety of antimicrobial resistance profiles, reinforces the theory that these river waters can be a pool of antimicrobial