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Sample records for aeruginosa environmental isolate

  1. Pseudomonas aeruginosa clinical and environmental isolates constitute a single population with high phenotypic diversity

    PubMed Central

    2014-01-01

    Background Pseudomonas aeruginosa is an opportunistic pathogen with a high incidence of hospital infections that represents a threat to immune compromised patients. Genomic studies have shown that, in contrast to other pathogenic bacteria, clinical and environmental isolates do not show particular genomic differences. In addition, genetic variability of all the P. aeruginosa strains whose genomes have been sequenced is extremely low. This low genomic variability might be explained if clinical strains constitute a subpopulation of this bacterial species present in environments that are close to human populations, which preferentially produce virulence associated traits. Results In this work, we sequenced the genomes and performed phenotypic descriptions for four non-human P. aeruginosa isolates collected from a plant, the ocean, a water-spring, and from dolphin stomach. We show that the four strains are phenotypically diverse and that this is not reflected in genomic variability, since their genomes are almost identical. Furthermore, we performed a detailed comparative genomic analysis of the four strains studied in this work with the thirteen previously reported P. aeruginosa genomes by means of describing their core and pan-genomes. Conclusions Contrary to what has been described for other bacteria we have found that the P. aeruginosa core genome is constituted by a high proportion of genes and that its pan-genome is thus relatively small. Considering the high degree of genomic conservation between isolates of P. aeruginosa from diverse environments, including human tissues, some implications for the treatment of infections are discussed. This work also represents a methodological contribution for the genomic study of P. aeruginosa, since we provide a database of the comparison of all the proteins encoded by the seventeen strains analyzed. PMID:24773920

  2. Pseudomonas aeruginosa in Dairy Goats: Genotypic and Phenotypic Comparison of Intramammary and Environmental Isolates

    PubMed Central

    Scaccabarozzi, Licia; Leoni, Livia; Ballarini, Annalisa; Barberio, Antonio; Locatelli, Clara; Casula, Antonio; Bronzo, Valerio; Pisoni, Giuliano; Jousson, Olivier; Morandi, Stefano; Rapetti, Luca; García-Fernández, Aurora; Moroni, Paolo

    2015-01-01

    Following the identification of a case of severe clinical mastitis in a Saanen dairy goat (goat A), an average of 26 lactating goats in the herd was monitored over a period of 11 months. Milk microbiological analysis revealed the presence of Pseudomonas aeruginosa in 7 of the goats. Among these 7 does, only goat A showed clinical signs of mastitis. The 7 P. aeruginosa isolates from the goat milk and 26 P. aeruginosa isolates from environmental samples were clustered by RAPD-PCR and PFGE analyses in 3 genotypes (G1, G2, G3) and 4 clusters (A, B, C, D), respectively. PFGE clusters A and B correlated with the G1 genotype and included the 7 milk isolates. Although it was not possible to identify the infection source, these results strongly suggest a spreading of the infection from goat A. Clusters C and D overlapped with genotypes G2 and G3, respectively, and included only environmental isolates. The outcome of the antimicrobial susceptibility test performed on the isolates revealed 2 main patterns of multiple resistance to beta-lactam antibiotics and macrolides. Virulence related phenotypes were analyzed, such as swarming and swimming motility, production of biofilm and production of secreted virulence factors. The isolates had distinct phenotypic profiles, corresponding to genotypes G1, G2 and G3. Overall, correlation analysis showed a strong correlation between sampling source, RAPD genotype, PFGE clusters, and phenotypic clusters. The comparison of the levels of virulence related phenotypes did not indicate a higher pathogenic potential in the milk isolates as compared to the environmental isolates. PMID:26606430

  3. Slime production a virulence marker in Pseudomonas aeruginosa strains isolated from clinical and environmental specimens: a comparative study of two methods.

    PubMed

    Prasad, S Vishnu; Ballal, Mamatha; Shivananda, P G

    2009-01-01

    Detection of slime in Pseudomonas aeruginosa can be useful in understanding the virulence of this organism. Here, comparative studies of two phenotypic methods using the tube method and the spectrophotometric method for slime production from 100 clinically and 21 environmentally significant isolates of P. aeruginosa were performed. A total of 68 isolates were positive by either of the tests whereas only 34 were positive by both the tests. The tube method detected slime significantly in more number of isolates than the spectrophotometric method. The tube test was found to be superior to the spectrophotometric method in ease of performance, interpretation and sensitivity. Among the clinical isolates, systemic isolates produce less slime compared to wound, respiratory and urinary isolates. Isolates from the hospital environment produced more slime indicating that this virulence marker helps the organism to survive for longer periods and cause nosocomial infections.

  4. Genomic characterisation of environmental Pseudomonas aeruginosa isolated from dental unit waterlines revealed the insertion sequence ISPa11 as a chaotropic element.

    PubMed

    Vincent, Antony T; Freschi, Luca; Jeukens, Julie; Kukavica-Ibrulj, Irena; Emond-Rheault, Jean-Guillaume; Leduc, Annie; Boyle, Brian; Jean-Pierre, Fabrice; Groleau, Marie-Christine; Déziel, Eric; Barbeau, Jean; Charette, Steve J; Levesque, Roger C

    2017-09-01

    The bacterium Pseudomonas aeruginosa is well known to have a remarkable adaptive capacity allowing it to colonise many environments. A recent study on environmental isolates from dental unit waterlines (DUWLs) hinted at a genetic clustering into two groups. Isolates from one of these groups, named cluster III, were shown to have unusual phenotypes for environmental isolates, such as an increased biofilm production. To have a better ecological view, more specifically on isolates from cluster III, the complete genomes of 39 isolates including 16 from DUWLs were sequenced. In addition to an investigation of antibiotic resistance and secretion system gene content, a molecular phylogeny allowed confirmation of the split of the 16 environmental isolates in two groups and also sheds light on a correlation between the phylogenetic positions and the serotypes of the isolates. Isolates from cluster III harboured insertion sequences ISPa11 inserted into the O-specific antigen biosynthesis clusters and the gene lasR, encoding for a master regulator of the quorum sensing. Investigation of key regulators revealed another truncated gene, gacS. Alteration in lasR and gacS genes was consistent with phenotypic assays confirming their inactivation. These results bring new perspectives regarding the ecological adaptive potential of P. aeruginosa. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Environmental Pseudomonads Inhibit Cystic Fibrosis Patient-Derived Pseudomonas aeruginosa.

    PubMed

    Chatterjee, Payel; Davis, Elizabeth; Yu, Fengan; James, Sarah; Wildschutte, Julia H; Wiegmann, Daniel D; Sherman, David H; McKay, Robert M; LiPuma, John J; Wildschutte, Hans

    2017-01-15

    Pseudomonas aeruginosa is an opportunistic pathogen which is evolving resistance to many currently used antibiotics. While much research has been devoted to the roles of pathogenic P. aeruginosa in cystic fibrosis (CF) patients, less is known of its ecological properties. P. aeruginosa dominates the lungs during chronic infection in CF patients, yet its abundance in some environments is less than that of other diverse groups of pseudomonads. Here, we sought to determine if clinical isolates of P. aeruginosa are vulnerable to environmental pseudomonads that dominate soil and water habitats in one-to-one competitions which may provide a source of inhibitory factors. We isolated a total of 330 pseudomonads from diverse habitats of soil and freshwater ecosystems and competed these strains against one another to determine their capacity for antagonistic activity. Over 900 individual inhibitory events were observed. Extending the analysis to P. aeruginosa isolates revealed that clinical isolates, including ones with increased alginate production, were susceptible to competition by multiple environmental strains. We performed transposon mutagenesis on one isolate and identified an ∼14.8-kb locus involved in antagonistic activity. Only two other environmental isolates were observed to carry the locus, suggesting the presence of additional unique compounds or interactions among other isolates involved in outcompeting P. aeruginosa This collection of strains represents a source of compounds that are active against multiple pathogenic strains. With the evolution of resistance of P. aeruginosa to currently used antibiotics, these environmental strains provide opportunities for novel compound discovery against drug-resistant clinical strains.

  6. Whole genome and transcriptome analyses of environmental antibiotic sensitive and multi-resistant Pseudomonas aeruginosa isolates exposed to waste water and tap water

    PubMed Central

    Schwartz, Thomas; Armant, Olivier; Bretschneider, Nancy; Hahn, Alexander; Kirchen, Silke; Seifert, Martin; Dötsch, Andreas

    2015-01-01

    The fitness of sensitive and resistant Pseudomonas aeruginosa in different aquatic environments depends on genetic capacities and transcriptional regulation. Therefore, an antibiotic-sensitive isolate PA30 and a multi-resistant isolate PA49 originating from waste waters were compared via whole genome and transcriptome Illumina sequencing after exposure to municipal waste water and tap water. A number of different genomic islands (e.g. PAGIs, PAPIs) were identified in the two environmental isolates beside the highly conserved core genome. Exposure to tap water and waste water exhibited similar transcriptional impacts on several gene clusters (antibiotic and metal resistance, genetic mobile elements, efflux pumps) in both environmental P. aeruginosa isolates. The MexCD-OprJ efflux pump was overexpressed in PA49 in response to waste water. The expression of resistance genes, genetic mobile elements in PA49 was independent from the water matrix. Consistently, the antibiotic sensitive strain PA30 did not show any difference in expression of the intrinsic resistance determinants and genetic mobile elements. Thus, the exposure of both isolates to polluted waste water and oligotrophic tap water resulted in similar expression profiles of mentioned genes. However, changes in environmental milieus resulted in rather unspecific transcriptional responses than selected and stimuli-specific gene regulation. PMID:25186059

  7. Whole genome and transcriptome analyses of environmental antibiotic sensitive and multi-resistant Pseudomonas aeruginosa isolates exposed to waste water and tap water.

    PubMed

    Schwartz, Thomas; Armant, Olivier; Bretschneider, Nancy; Hahn, Alexander; Kirchen, Silke; Seifert, Martin; Dötsch, Andreas

    2015-01-01

    The fitness of sensitive and resistant Pseudomonas aeruginosa in different aquatic environments depends on genetic capacities and transcriptional regulation. Therefore, an antibiotic-sensitive isolate PA30 and a multi-resistant isolate PA49 originating from waste waters were compared via whole genome and transcriptome Illumina sequencing after exposure to municipal waste water and tap water. A number of different genomic islands (e.g. PAGIs, PAPIs) were identified in the two environmental isolates beside the highly conserved core genome. Exposure to tap water and waste water exhibited similar transcriptional impacts on several gene clusters (antibiotic and metal resistance, genetic mobile elements, efflux pumps) in both environmental P. aeruginosa isolates. The MexCD-OprJ efflux pump was overexpressed in PA49 in response to waste water. The expression of resistance genes, genetic mobile elements in PA49 was independent from the water matrix. Consistently, the antibiotic sensitive strain PA30 did not show any difference in expression of the intrinsic resistance determinants and genetic mobile elements. Thus, the exposure of both isolates to polluted waste water and oligotrophic tap water resulted in similar expression profiles of mentioned genes. However, changes in environmental milieus resulted in rather unspecific transcriptional responses than selected and stimuli-specific gene regulation. © 2014 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  8. Pyocyanine Biosynthetic Genes in Clinical and Environmental Isolates of Pseudomonas aeruginosa and Detection of Pyocyanine’s Antimicrobial Effects with or without Colloidal Silver Nanoparticles

    PubMed Central

    Nowroozi, Jamileh; Akhavan Sepahi, Abbas; Rashnonejad, Afrooz

    2012-01-01

    Objective: Pyocyanine plays an important role in the pathogenesis of Pseudomonas aeruginosa, (P. aeruginosa) and is known to have inhibitory and bactericidal effects. This study has aimed to detect the phenazine biosynthetic operon (phz ABCDEFG) and two phenazine modifying genes (phzM and phzS) by polymerase chain reaction (PCR) and detection of its possible protein bands by sodium dodecyl sulfate - polyacrylamide gel electrophoresis (SDS-PAGE). The antimicrobial effects of pyocyanine alone and mixed with colloidal silver nanoparticles were studied. Materials and Methods: In this descriptive study, clinical and environmental species of P. aeruginosa were isolated by thioglycollate medium culture and cetrimide agar, respectively. The existence of a phenazine biosynthetic operon and two phenazine modifying genes as well as their protein products were confirmed by PCR and SDS-PAGE, respectively. Pyocyanine was extracted with chloroform and its antimicrobial effects against bacteria such as; Escherichia coli (E. coli), P. aeruginosaand Staphylococcus aureus (S. aureus) bacteria and yeast Candida albicans (C. albicans) were tested using well, spot and disk diffusion methods. Results: In this study, 3 out of 48 clinical strains were unable to produce pyocyanine on cetrimide and Mueller Hinton (MH) agar. Two strains did not have phenazine modifying gene bands. Another strain did not have the possible protein band of the phzM gene. Pyocyanine had antimicrobial effects against the microbial strains, which increased in the presence of silver nanoparticles. Conclusion: According to the results of the present study, some P. aeruginosa strains are unable to produce pyocyanine due to the absence of the phzM or phzS genes. Therefore, these genes have an important role in pyocyanine production in P. aeruginosa. Pyocyanine shows synergistic antimicrobial effects in the presence of silver nanoparticles against microbial strains. PMID:23626932

  9. Environmental Pseudomonads Inhibit Cystic Fibrosis Patient-Derived Pseudomonas aeruginosa

    PubMed Central

    Chatterjee, Payel; Davis, Elizabeth; Yu, Fengan; James, Sarah; Wildschutte, Julia H.; Wiegmann, Daniel D.; Sherman, David H.; McKay, Robert M.; LiPuma, John J.

    2016-01-01

    ABSTRACT Pseudomonas aeruginosa is an opportunistic pathogen which is evolving resistance to many currently used antibiotics. While much research has been devoted to the roles of pathogenic P. aeruginosa in cystic fibrosis (CF) patients, less is known of its ecological properties. P. aeruginosa dominates the lungs during chronic infection in CF patients, yet its abundance in some environments is less than that of other diverse groups of pseudomonads. Here, we sought to determine if clinical isolates of P. aeruginosa are vulnerable to environmental pseudomonads that dominate soil and water habitats in one-to-one competitions which may provide a source of inhibitory factors. We isolated a total of 330 pseudomonads from diverse habitats of soil and freshwater ecosystems and competed these strains against one another to determine their capacity for antagonistic activity. Over 900 individual inhibitory events were observed. Extending the analysis to P. aeruginosa isolates revealed that clinical isolates, including ones with increased alginate production, were susceptible to competition by multiple environmental strains. We performed transposon mutagenesis on one isolate and identified an ∼14.8-kb locus involved in antagonistic activity. Only two other environmental isolates were observed to carry the locus, suggesting the presence of additional unique compounds or interactions among other isolates involved in outcompeting P. aeruginosa. This collection of strains represents a source of compounds that are active against multiple pathogenic strains. With the evolution of resistance of P. aeruginosa to currently used antibiotics, these environmental strains provide opportunities for novel compound discovery against drug-resistant clinical strains. IMPORTANCE We demonstrate that clinical CF-derived isolates of P. aeruginosa are susceptible to competition in the presence of environmental pseudomonads. We observed that many diverse environmental strains exhibited varied

  10. Isolation of oxidase-negative Pseudomonas aeruginosa from sputum culture.

    PubMed

    Hampton, K D; Wasilauskas, B L

    1979-05-01

    Two isolates of Pseudomonas aeruginosa lacking characteristic indophenol oxidase were recovered from a sputum specimen. A discussion of the characteristic biochemical tests and antibiograms along with a possible explanation for this phenomenon is presented.

  11. Comparative analysis of the volatile metabolomes of Pseudomonas aeruginosa clinical isolates.

    PubMed

    Bean, Heather D; Rees, Christiaan A; Hill, Jane E

    2016-11-21

    Pseudomonas aeruginosa is a nearly ubiquitous Gram-negative organism, well known to occupy a multitude of environmental niches and cause human infections at a variety of bodily sites, due to its metabolic flexibility, secondary to extensive genetic heterogeneity at the species level. Because of its dynamic metabolism and clinical importance, we sought to perform a comparative analysis on the volatile metabolome (the 'volatilome') produced by P. aeruginosa clinical isolates. In this study, we analyzed the headspace volatile molecules of 24 P. aeruginosa clinical isolates grown in vitro, using 2D gas chromatography time-of-flight mass spectrometry (GC  ×  GC-TOFMS). We identified 391 non-redundant compounds that we associate with the growth and metabolism of P. aeruginosa (the 'pan-volatilome'). Of these, 70 were produced by all 24 isolates (the 'core volatilome'), 52 by only a single isolate, and the remaining 269 volatile molecules by a subset. Sixty-five of the detected compounds could be assigned putative compound identifications, of which 43 had not previously been associated with P. aeruginosa. Using the accessory volatile molecules, we determined the inter-strain variation in the metabolomes of these isolates, clustering strains by their metabotypes. Assessing the extent of metabolomic diversity in P. aeruginosa through an analysis of the volatile molecules that it produces is a critical next step in the identification of novel diagnostic or prognostic biomarkers.

  12. The cif Virulence Factor Gene Is Present in Isolates From Patients With Pseudomonas aeruginosa Keratitis.

    PubMed

    Bahl, Christopher D; St Laurent, Jessica D; Karthikeyan, R Siva Ganesa; Priya, J Lakshmi; Prajna, Lalitha; Zegans, Michael E; Madden, Dean R

    2017-03-01

    To determine whether the cif gene is present in pathogenic Pseudomonas aeruginosa isolates from patients with bacterial keratitis at Aravind Eye Hospital, a referral eye care center in southern India, and from corresponding environmental isolates. Polymerase chain reaction amplification was performed on strains of P. aeruginosa isolated from ocular infections and environmental soil samples were collected from the area surrounding Aravind Eye Hospital. DNA sequencing of 16S ribosomal DNA amplicons was performed to verify strain identity. We determined that 45 of 48 patient isolates carry a genomic copy of cif. Analysis of a catalog of environmental strains previously isolated from the surrounding area revealed that only 4 of 10 P. aeruginosa strains and 1 of 14 strains of related species carry the cif gene. This is the first study to show that P. aeruginosa strains with ocular pathogenicity carry the cif gene and that the presence of this gene may be enriched over its prevalence in the environment. Taken together, these results suggest a potential role for Cif in acute bacterial keratitis.

  13. Pseudomonas aeruginosa isolates from dental unit waterlines can be divided in two distinct groups, including one displaying phenotypes similar to isolates from cystic fibrosis patients

    PubMed Central

    Ouellet, Myriam M.; Leduc, Annie; Nadeau, Christine; Barbeau, Jean; Charette, Steve J.

    2015-01-01

    Pseudomonas aeruginosa displays broad genetic diversity, giving it an astonishing capacity to adapt to a variety of environments and to infect a wide range of hosts. While many P. aeruginosa isolates of various origins have been analyzed, isolates from cystic fibrosis (CF) patients have received the most attention. Less is known about the genetic and phenotypic diversity of P. aeruginosa isolates that colonize other environments where flourishing biofilms can be found. In the present study, 29 P. aeruginosa isolates from dental unit waterlines and CF patients were collected and their genetic and phenotypes profiles were compared to determine whether environmental and clinical isolates are related. The isolates were first classified using the random amplified polymorphic DNA method. This made it possible to distribute the isolates into one clinical cluster and two environmental clusters. The isolates in the environmental cluster that were genetically closer to the clinical cluster also displayed phenotypes similar to the clinical isolates. The isolates from the second environmental cluster displayed opposite phenotypes, particularly an increased capacity to form biofilms. The isolates in this cluster were also the only ones harboring genes that encoded specific epimerases involved in the synthesis of lipopolysaccharides, which could explain their increased ability to form biofilms. In conclusion, the isolates from the dental unit waterlines could be distributed into two clusters, with some of the environmental isolates resembled the clinical isolates. PMID:25653647

  14. Mobile genetic elements of Pseudomonas aeruginosa isolates from hydrotherapy facility and respiratory infections.

    PubMed

    Pereira, S G; Cardoso, O

    2014-03-01

    The content of mobile genetic elements in Pseudomonas aeruginosa isolates of a pristine natural mineral water system associated with healthcare was compared with clinical isolates from respiratory infections. One isolate, from the therapy pool circuit, presented a class 1 integron, with 100% similarity to a class 1 integron contained in plasmid p4800 of the Klebsiella pneumoniae Kp4800 strain, which is the first time it has been reported in P. aeruginosa. Class 1 integrons were found in 25.6% of the clinical isolates. PAGI1 orf3 was more prevalent in environmental isolates, while PAGI2 c105 and PAGI3 sg100 were more prevalent in clinical isolates. Plasmids were not observed in either population. © 2013 The Authors Clinical Microbiology and Infection © 2013 European Society of Clinical Microbiology and Infectious Diseases.

  15. Tracking down antibiotic-resistant Pseudomonas aeruginosa isolates in a wastewater network.

    PubMed

    Slekovec, Céline; Plantin, Julie; Cholley, Pascal; Thouverez, Michelle; Talon, Daniel; Bertrand, Xavier; Hocquet, Didier

    2012-01-01

    The Pseudomonas aeruginosa-containing wastewater released by hospitals is treated by wastewater treatment plants (WWTPs), generating sludge, which is used as a fertilizer, and effluent, which is discharged into rivers. We evaluated the risk of dissemination of antibiotic-resistant P. aeruginosa (AR-PA) from the hospital to the environment via the wastewater network. Over a 10-week period, we sampled weekly 11 points (hospital and urban wastewater, untreated and treated water, sludge) of the wastewater network and the river upstream and downstream of the WWTP of a city in eastern France. We quantified the P. aeruginosa load by colony counting. We determined the susceptibility to 16 antibiotics of 225 isolates, which we sorted into three categories (wild-type, antibiotic-resistant and multidrug-resistant). Extended-spectrum β-lactamases (ESBLs) and metallo-β-lactamases (MBLs) were identified by gene sequencing. All non-wild-type isolates (n = 56) and a similar number of wild-type isolates (n = 54) were genotyped by pulsed-field gel electrophoresis and multilocus sequence typing. Almost all the samples (105/110, 95.5%) contained P. aeruginosa, with high loads in hospital wastewater and sludge (≥3×10(6) CFU/l or/kg). Most of the multidrug-resistant isolates belonged to ST235, CC111 and ST395. They were found in hospital wastewater and some produced ESBLs such as PER-1 and MBLs such as IMP-29. The WWTP greatly reduced P. aeruginosa counts in effluent, but the P. aeruginosa load in the river was nonetheless higher downstream than upstream from the WWTP. We conclude that the antibiotic-resistant P. aeruginosa released by hospitals is found in the water downstream from the WWTP and in sludge, constituting a potential risk of environmental contamination.

  16. Draft Genome Sequence of the Pseudomonas aeruginosa Bloodstream Isolate PABL056

    PubMed Central

    Allen, Jonathan P.; Hauser, Alan R.

    2012-01-01

    Pseudomonas aeruginosa is an important cause of disease in hospitalized and immunocompromised patients. The genome of P. aeruginosa is among the largest of bacteria pathogenic to humans. We present the draft genome sequence of P. aeruginosa strain PABL056, a human bloodstream isolate with the largest genome yet reported in P. aeruginosa. PMID:23045505

  17. AMINOGLYCOSIDE RESISTANCE GENES IN Pseudomonas aeruginosa ISOLATES FROM CUMANA, VENEZUELA

    PubMed Central

    TEIXEIRA, Bertinellys; RODULFO, Hectorina; CARREÑO, Numirin; GUZMÁN, Militza; SALAZAR, Elsa; DONATO, Marcos DE

    2016-01-01

    The enzymatic modification of aminoglycosides by aminoglycoside-acetyltransferases (AAC), aminoglycoside-adenyltransferases (AAD), and aminoglycoside-phosphotransferases (APH), is the most common resistance mechanism in P. aeruginosa and these enzymes can be coded on mobile genetic elements that contribute to their dispersion. One hundred and thirty seven P. aeruginosa isolates from the University Hospital, Cumana, Venezuela (HUAPA) were evaluated. Antimicrobial susceptibility was determined by the disk diffusion method and theaac, aadB and aph genes were detected by PCR. Most of the P. aeruginosa isolates (33/137) were identified from the Intensive Care Unit (ICU), mainly from discharges (96/137). The frequency of resistant P. aeruginosaisolates was found to be higher for the aminoglycosides tobramycin and amikacin (30.7 and 29.9%, respectively). Phenotype VI, resistant to these antibiotics, was the most frequent (14/49), followed by phenotype I, resistant to all the aminoglycosides tested (12/49). The aac(6´)-Ib,aphA1 and aadB genes were the most frequently detected, and the simultaneous presence of several resistance genes in the same isolate was demonstrated. Aminoglycoside resistance in isolates ofP. aeruginosa at the HUAPA is partly due to the presence of the aac(6´)-Ib, aphA1 andaadB genes, but the high rates of antimicrobial resistance suggest the existence of several mechanisms acting together. This is the first report of aminoglycoside resistance genes in Venezuela and one of the few in Latin America. PMID:27007556

  18. AMINOGLYCOSIDE RESISTANCE GENES IN Pseudomonas aeruginosa ISOLATES FROM CUMANA, VENEZUELA.

    PubMed

    Teixeira, Bertinellys; Rodulfo, Hectorina; Carreño, Numirin; Guzmán, Militza; Salazar, Elsa; De Donato, Marcos

    2016-01-01

    The enzymatic modification of aminoglycosides by aminoglycoside-acetyltransferases (AAC), aminoglycoside-adenyltransferases (AAD), and aminoglycoside-phosphotransferases (APH), is the most common resistance mechanism in P. aeruginosa and these enzymes can be coded on mobile genetic elements that contribute to their dispersion. One hundred and thirty seven P. aeruginosa isolates from the University Hospital, Cumana, Venezuela (HUAPA) were evaluated. Antimicrobial susceptibility was determined by the disk diffusion method and theaac, aadB and aph genes were detected by PCR. Most of the P. aeruginosa isolates (33/137) were identified from the Intensive Care Unit (ICU), mainly from discharges (96/137). The frequency of resistant P. aeruginosaisolates was found to be higher for the aminoglycosides tobramycin and amikacin (30.7 and 29.9%, respectively). Phenotype VI, resistant to these antibiotics, was the most frequent (14/49), followed by phenotype I, resistant to all the aminoglycosides tested (12/49). The aac(6´)-Ib,aphA1 and aadB genes were the most frequently detected, and the simultaneous presence of several resistance genes in the same isolate was demonstrated. Aminoglycoside resistance in isolates ofP. aeruginosa at the HUAPA is partly due to the presence of the aac(6´)-Ib, aphA1 andaadB genes, but the high rates of antimicrobial resistance suggest the existence of several mechanisms acting together. This is the first report of aminoglycoside resistance genes in Venezuela and one of the few in Latin America.

  19. Pseudomonas aeruginosa population structure revisited under environmental focus: impact of water quality and phage pressure.

    PubMed

    Selezska, Katherina; Kazmierczak, Marlon; Müsken, Mathias; Garbe, Julia; Schobert, Max; Häussler, Susanne; Wiehlmann, Lutz; Rohde, Christine; Sikorski, Johannes

    2012-08-01

    Pseudomonas aeruginosa attracts research attention as a common opportunistic nosocomial pathogen causing severe health problems in humans. Nevertheless, its primary habitat is the natural environment. Here, we relate the genetic diversity of 381 environmental isolates from rivers in northern Germany to ecological factors such as river system, season of sampling and different levels of water quality. From representatives of 99 environmental clones, also in comparison with 91 clinical isolates, we determined motility phenotypes, virulence factors, biofilm formation, serotype and the resistance to seven environmental P.aeruginosa phages. The integration of genetic, ecological and phenotypic data showed (i) the presence of several extended clonal complexes (ecc) which are non-uniformly distributed across different water qualities, and (ii) a correlation of the hosts' serotype composition with susceptibility towards distinct groups of environmental phages. For at least one ecc (eccB), we assumed the ecophysiological differences on environmental water adaptation and phage resistance to be so distinct as to reinforce an environmentally driven cladogenic split from the remainder of P.aeruginosa. In summary, we conclude that the majority of the microevolutionary population dynamics of P.aeruginosa were shaped by the natural environment and not by the clinical habitat. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  20. Isolation of an iron-binding compound from Pseudomonas aeruginosa.

    PubMed Central

    Cox, C D; Graham, R

    1979-01-01

    An iron-binding compound was isolated from ethyl acetate extracts of culture supernatant fluids of Pseudomonas aeruginosa and was purified by successive paper and thin-layer chromatographic procedures. The purified compound was characterized by UV, visible, infrared, and fluorescence spectroscopy. The compound possesses phenolic characteristics, with little or no similarity to dihydroxybenzoates and no indication of a hydroxamate group. P. aeruginosa synthesized the compound during active growth in culture media containing less than 5 X 10(-6) M added FeCl3. When added to iron-poor cultures of P. aeruginosa, the compound promoted the growth of the bacterium and also reversed growth inhibition by the iron chelator ethylenediamine-di-(o-hydroxyphenylacetic acid). PMID:104968

  1. Epidemiological investigation of Pseudomonas aeruginosa nosocomial bacteraemia isolates by PCR-based DNA fingerprinting analysis.

    PubMed

    Liu, Y; Davin-Regli, A; Bosi, C; Charrel, R N; Bollet, C

    1996-11-01

    Between July 1994 and March 1995, 64 isolates of Pseudomonas aeruginosa were implicated in bacteraemia in 25 cancer patients in five wards of two hospitals. These, together with 24 environmental isolates and one isolate from a bacteraemia in a non-cancer patient were examined by three PCR-based DNA fingerprinting methods: random amplified polymorphic DNA (RAPD), enterobacterial-repetitive intergenic consensus (ERIC)-PCR, and 16S-23S spacer region-based RAPD. These methods were reproducible, discriminatory and showed close agreement; all indicated that 47 isolates that had caused bacteraemia in 19 cancer patients were indistinguishable. Seventeen other isolates that had caused bacteraemia in 10 cancer patients were discriminated into eight further groups, and the 24 environmental and non-cancer patient isolates into further distinct groups. No environmental source of the epidemic strain was found, but it was suspected that the outbreak was related to infusion implants.

  2. Characterization of colony morphology variants isolated from Pseudomonas aeruginosa biofilms.

    PubMed

    Kirisits, Mary Jo; Prost, Lynne; Starkey, Melissa; Parsek, Matthew R

    2005-08-01

    In this study, we report the isolation of small, rough, strongly cohesive colony morphology variants from aging Pseudomonas aeruginosa PAO1 biofilms. Similar to many of the P. aeruginosa colony morphology variants previously described in the literature, these variants autoaggregate in liquid culture and hyperadhere to solid surfaces. They also exhibit increased hydrophobicity and reduced motility compared to the wild-type parent strain. Despite the similarities in appearance of our colony morphology variant isolates on solid medium, the isolates showed a range of responses in various phenotypic assays. These variants form biofilms with significant three-dimensional structure and more biomass than the wild-type parent. To further explore the nature of the variants, their transcriptional profiles were evaluated. The variants generally showed increased expression of the psl and pel loci, which have been previously implicated in the adherence of P. aeruginosa to solid surfaces. When a mutation in the psl locus was introduced into a colony morphology variant, the colony morphology was only partially affected, but hyperadherence and autoaggregation were lost. Finally, similar colony morphology variants were found in isolates from cystic fibrosis patients. These variants displayed many of the same characteristics as the laboratory variants, suggesting a link between laboratory and cystic fibrosis biofilms.

  3. High level of resistance to aztreonam and ticarcillin in Pseudomonas aeruginosa isolated from soil of different crops in Brazil.

    PubMed

    Pitondo-Silva, André; Martins, Vinicius Vicente; Fernandes, Ana Flavia Tonelli; Stehling, Eliana Guedes

    2014-03-01

    Pseudomonas aeruginosa can be found in water, soil, plants and, human and animal fecal samples. It is an important nosocomial pathogenic agent characterized by an intrinsic resistance to multiple antimicrobial agents and the ability to develop high-level (acquired) multidrug resistance through some mechanisms, among them, by the acquisition of plasmids and integrons, which are mobile genetic elements. In this study, 40 isolates from Brazilian soil were analyzed for antibiotic resistance, presence of integrons and plasmidial profile. The results demonstrated that the vast majority of the isolates have shown resistance for aztreonam (92.5%, n=37) and ticarcillin (85%, n=34), four isolates presented plasmids and eight isolates possess the class 1 integron. These results demonstrated that environmental isolates of P. aeruginosa possess surprising antibiotic resistance profile to aztreonam and ticarcillin, two antimicrobial agents for clinical treatment of cystic fibrosis patients and other infections occurred by P. aeruginosa.

  4. First report of VIM-2 metallo-β-lactamases producing Pseudomonas aeruginosa isolates in Morocco.

    PubMed

    Maroui, Itto; Barguigua, Abouddihaj; Aboulkacem, Asmae; Ouarrak, Khadija; Sbiti, Mohammed; Louzi, Housssain; Timinouni, Mohammed; Belhaj, Abdelhaq

    2016-03-01

    The emergence and the rapid spread of Pseudomonas aeruginosa carrying carbapenemases represent a serious threat to public health due to their delicate therapy. This work was performed to establish the resistance profile and to detect carbapenemases producing in 123 P. aeruginosa isolates. Among these 55 are environmental isolates and 68 are from the two major hospitals of Meknes-Tafilalet region in Morocco. All strains were tested against 14 antipseudomonal drugs by disc diffusion method. On carbapenem resistant strains minimum inhibitory concentrations of imipenem were determined by the E-test method. The modified Hodge test and EDTA tests were used for the detection of carbapenemases and metallo-β-lactamases (MBLs), respectively. PCR and DNA sequencing were conducted to detect carbapenemase-encoding genes and the enzyme types. 12% of isolates was susceptible to all antibiotics tested and Carbapenem resistance was observed in 33 P. aeruginosa isolates, 33.3% of them were multi-drug resistant. Among carbapenem resistant strains only two (6.1%) were positive for carbapenemases and also for MBLs. In addition to their resistance to almost all β-lactams tested, the MBLs producing strains were resistant to aminoglycosides. Molecular biology techniques confirmed the phenotypic results obtained for the two strains carbapenemase producers and demonstrated that each one of them carried blaVIM-2. The present study reports the first isolation of blaVIM genes in clinical isolates of P. aeruginosa in Morocco. Such isolates represent a serious emerging threat requiring strict hygiene measures to better control their spread. Copyright © 2015 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  5. Molecular epidemiology provides evidence of genotypic heterogeneity of multidrug-resistant Pseudomonas aeruginosa serotype O:12 outbreak isolates from a pediatric hospital.

    PubMed Central

    Bingen, E; Bonacorsi, S; Rohrlich, P; Duval, M; Lhopital, S; Brahimi, N; Vilmer, E; Goering, R V

    1996-01-01

    Ribotyping randomly amplified polymorphic DNA analysis, and pulsed-field gel electrophoresis were used for the epidemiologic evaluation of eight Pseudomonas aeruginosa O:12 isolates obtained from eight children and two P. aeruginosa O:12 environmental isolates from a hematology ward. Randomly amplified polymorphic DNA analysis and pulsed-field gel electrophoresis were able to discriminate isolates that were indistinguishable by biochemical typing, O serotyping or ribotyping. PMID:8940479

  6. [Simultaneous isolation of MRSA and Pseudomonas aeruginosa using a novel selective and differential PMAC agar].

    PubMed

    Taguchi, F; Okuda, S; Uchino, U; Muraoka, H; Hasegawa, M; Kobayashi, I

    1996-09-01

    PMAC agar, a novel, selective and differential medium has been developed and was subjected for evaluation of its selective and differential capability of methicillin resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa from other bacteria such as Bacillus, Micrococcus, Gram-negative bacteria and drug resistant ones. Growth of MRSA and P. aeruginosa on PMAC agar was facilitated and their colonies were easily differentiated. Colonies of MRSA after 24 approximately 48 h incubation at 35 degrees C were small (2 to 4 mm in diameter), smooth and egg-yolk reaction positive. On the other hand, P. aeruginosa with pigment production (pyocianin, fluorescin or pyomelanin) formed large (2.5 to 7.0 mm in diameter), brownish black or brown colonies with a creamy edge. PMAC agar did not allow to grow unwanted bacteria tested except certain species formerly classified to Pseudomonas such as Burkholderia and Stenotrophomonas. However multi-drug resistant strains such as Enterobacter cloacae, Serratia marcescens and Acinetobacter calcoaceticus formed extremely small colonies. PMAC agar is recommended as a novel, useful medium for isolation, differentiation and presumptive identification of MRSA and P. aeruginosa from clinical and environmental sources.

  7. Genotyping of Pseudomonas aeruginosa isolated from cockroaches and human urine.

    PubMed

    Saitou, Keiko; Furuhata, Katsunori; Fukuyama, Masafumi

    2010-10-01

    Molecular-epidemiological analysis of Pseudomonas aeruginosa isolated from cockroaches captured in hospitals and from patient urine was performed, employing randomly amplified polymorphic DNA (RAPD) analysis to investigate the usefulness of RAPD analysis. Four specific bands at positions of 993, 875, 521, and 402 bp were commonly detected using primer 272 in 16 of 45 cockroach-derived strains (35.6%), but not in 21 urine-derived strains. On analysis using primer 208, 4 specific bands at positions of 1,235, 1,138, 1,068, and 303 bp were commonly detected in 15 of the 45 cockroach-derived (33.3%) and 10 of the 21 patient urine-derived (47.6%) strains, in a total of 25 of 66 strains (37.8%). On cluster analysis, 12 (48.5%) and 16 (66.7%) clusters were grouped based on a homology of 89% or greater, using primer 272 and primer 208, respectively, showing that primer 208 was suitable for the confirmation of diversity. Seven patterns were clustered based on 100% homology using either primer, and 6 of these consisted of only cockroach-derived strains. In the individual groups with 100% homology, all strains in the group were isolated at an identical site during the same period. P. aeruginosa isolated from cockroaches showed diverse genotypes suggesting several sources of contamination, indicating the necessity for investigating infection control targeting cockroaches inhabiting hospitals.

  8. Antimicrobial Pressure of Ciprofloxacin and Gentamicin on Biofilm Development by an Endoscope-Isolated Pseudomonas aeruginosa

    PubMed Central

    Machado, Idalina; Graça, Joana; Lopes, Hélder; Lopes, Susana; Pereira, Maria O.

    2013-01-01

    This work aims at characterizing endoscope biofilm-isolated (PAI) and reference strain P. aeruginosa (PA) adhesion, biofilm formation and sensitivity to antibiotics. The recovery ability of the biofilm-growing bacteria subjected to intermittent antibiotic pressure (ciprofloxacin (CIP) and gentamicin (GM)), as well as the development of resistance towards antibiotics and benzalkonium chloride (BC), were also determined. The capacity of both strains to develop biofilms was greatly impaired in the presence of CIP and GM. Sanitization was not complete allowing biofilm recovery after the intermittent cycles of antibiotic pressure. The environmental pressure exerted by CIP and GM did not develop P. aeruginosa resistance to antibiotics nor cross-resistance towards BC. However, data highlighted that none of the antimicrobials led to complete biofilm eradication, allowing the recovery of the remaining adhered population possibly due to the selection of persister cells. This feature may lead to biofilm recalcitrance, reinforcement of bacterial attachment, and recolonization of other sites. PMID:25969768

  9. Heavy metal resistance and virulence profile in Pseudomonas aeruginosa isolated from Brazilian soils.

    PubMed

    Pitondo-Silva, André; Gonçalves, Guilherme Bartolomeu; Stehling, Eliana Guedes

    2016-08-01

    Pseudomonas aeruginosa is an opportunistic pathogen, which can have several virulence factors that confer on it the ability to cause severe, acute and chronic infections. Thus, the simultaneous occurrence of resistance to antibiotics and heavy metals associated with the presence of virulence genes is a potential threat to human health and environmental balance. This study aimed to investigate the resistance profile to heavy metals and the correlation of this phenotype of resistance to antimicrobials and to investigate the pathogenic potential of 46 P. aeruginosa isolates obtained from the soil of five Brazilian regions. The bacteria were evaluating for antimicrobial and heavy metal resistance, as well as the presence of plasmids and virulence genes. The isolates showed resistance to four different antibiotics and the majority (n = 44) had resistance to aztreonam or ticarcillin, furthermore, 32 isolates showed concomitant resistance to both of these antibiotics. A high prevalence of virulence genes was found, which highlights the pathogenic potential of the studied environmental isolates. Moreover, a high frequency of heavy metal resistance genes was also detected, however, the phenotypic results indicated that other genes and/or mechanisms should be related to heavy metal resistance. © 2016 APMIS. Published by John Wiley & Sons Ltd.

  10. Draft Genome Sequences of Four Pseudomonas aeruginosa Isolates Obtained from Patients with Chronic Obstructive Pulmonary Disease.

    PubMed

    Lira, Felipe; García-León, Guillermo; Oliver, Antonio; Martínez, José L

    2017-06-15

    Patients suffering chronic obstructive pulmonary disease are frequently infected by Pseudomonas aeruginosa Nevertheless, the number of sequenced isolates causing this type of infection is low. Here, we present the draft genomes of four P. aeruginosa isolates obtained from patients presenting chronic obstructive pulmonary disease. Copyright © 2017 Lira et al.

  11. Draft Genome Sequences of Pseudomonas aeruginosa Isolates from Wounded Military Personnel.

    PubMed

    Arivett, Brock A; Ream, Dave C; Fiester, Steven E; Kidane, Destaalem; Actis, Luis A

    2016-08-11

    Pseudomonas aeruginosa, a Gram-negative bacterium that causes severe hospital-acquired infections, is grouped as an ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogen because of its extensive drug resistance phenotypes and effects on human health worldwide. Five multidrug resistant P. aeruginosa strains isolated from wounded military personnel were sequenced and annotated in this work.

  12. 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

  13. Draft Genome Sequence of Beneficial Rice Rhizosphere Isolate Pseudomonas aeruginosa PUPa3

    PubMed Central

    Uzelac, Gordana; Bertani, Iris; Kojic, Milan; Paszkiewicz, Konrad H.; Studholme, David J.; Passos da Silva, Daniel

    2014-01-01

    Pseudomonas aeruginosa PUPa3 is a rhizosphere-colonizing and plant growth-promoting strain isolated from the rhizosphere of rice. This strain has, however, been shown to be pathogenic in two nonmammalian infection models. Here we report the draft genome sequence of P. aeruginosa PUPa3. PMID:24994800

  14. Draft Genome Sequence of Beneficial Rice Rhizosphere Isolate Pseudomonas aeruginosa PUPa3.

    PubMed

    Uzelac, Gordana; Bertani, Iris; Kojic, Milan; Paszkiewicz, Konrad H; Studholme, David J; Passos da Silva, Daniel; Venturi, Vittorio

    2014-07-03

    Pseudomonas aeruginosa PUPa3 is a rhizosphere-colonizing and plant growth-promoting strain isolated from the rhizosphere of rice. This strain has, however, been shown to be pathogenic in two nonmammalian infection models. Here we report the draft genome sequence of P. aeruginosa PUPa3.

  15. Draft Genome Sequence of an IMP-7-Producing Pseudomonas aeruginosa Bloodstream Infection Isolate from Australia

    PubMed Central

    Jennison, A.; Wailan, A. M.; Paterson, D. L.

    2017-01-01

    ABSTRACT IMP-7 is one of the two IMP-type carbapenemases that in Pseudomonas aeruginosa are not limited to a geographic area, but it has not been previously reported in the Australian setting. We report here the draft genome sequence of an Australian P. aeruginosa bloodstream infection isolate that contains IMP-7. PMID:28684579

  16. Draft Genome Sequence of an IMP-7-Producing Pseudomonas aeruginosa Bloodstream Infection Isolate from Australia.

    PubMed

    McCarthy, K L; Jennison, A; Wailan, A M; Paterson, D L

    2017-07-06

    IMP-7 is one of the two IMP-type carbapenemases that in Pseudomonas aeruginosa are not limited to a geographic area, but it has not been previously reported in the Australian setting. We report here the draft genome sequence of an Australian P. aeruginosa bloodstream infection isolate that contains IMP-7. Copyright © 2017 McCarthy et al.

  17. Emergence of Imipenem-Resistant Pseudomonas aeruginosa Clinical Isolates from Egypt Coharboring VIM and IMP Carbapenemases.

    PubMed

    El-Domany, Ramadan Ahmed; Emara, Mohamed; El-Magd, Mohammed A; Moustafa, Walaa H; Abdeltwab, Nesma M

    2017-09-01

    Pseudomonas aeruginosa is an important human pathogen and the leading cause of nosocomial infections. P. aeruginosa is characterized by massive intrinsic resistance to a multiple classes of antibiotics with carbapenems being the most potent inhibitor of P. aeruginosa and considered the first choice for its treatment. Therefore, it is crucial to investigate novel mechanisms of resistance of P. aeruginosa to carbapenems for achieving successful therapy. A total of 114 P. aeruginosa isolates from two university hospitals in Egypt were recruited in this study. Antimicrobial susceptibility testing revealed that 50 isolates (43.8%) exhibited multidrug-resistant (MDR) phenotype, of them 14 isolates (12.2%) were imipenem (IPM)-resistant. Of these 14 isolates, 13 isolates (11.4%) exhibited the metallo-β-lactamase (MBL) phenotype. MBLs encoding genes, VIM and IMP, were identified by PCR. PCR results revealed that four isolates harbored the VIM gene alone, one isolate harbored IMP gene alone, and four isolates harbored both genes. The correct size of PCR products of VIM and IMP genes (390 and 188 bp, respectively) were sequenced to confirm results of PCR and to look for any possible polymorphism among MBL genes of tested isolates. Data analysis of these sequences showed 100% identity of nucleotide sequences of MBL genes among tested Egyptian patients. To our knowledge, this is the first report of IMP carbapenemase-encoding gene in Africa and the first detection of the emergence of P. aeruginosa coproducing VIM and IMP genes in Egypt.

  18. Effect of Tyrosol and Farnesol on Virulence and Antibiotic Resistance of Clinical Isolates of Pseudomonas aeruginosa.

    PubMed

    Abdel-Rhman, Shaymaa Hassan; El-Mahdy, Areej Mostafa; El-Mowafy, Mohammed

    2015-01-01

    Mixed-species biofilms could create a protected environment that allows for survival to external antimicrobials and allows different bacterial-fungal interactions. Pseudomonas aeruginosa-Candida albicans coexistence is an example for such mixed-species community. Numerous reports demonstrated how P. aeruginosa or its metabolites could influence the growth, morphogenesis, and virulence of C. albicans. In this study, we investigated how the C. albicans quorum sensing compounds, tyrosol and farnesol, might affect Egyptian clinical isolates of P. aeruginosa regarding growth, antibiotic sensitivity, and virulence. We could demonstrate that tyrosol possesses an antibacterial activity against P. aeruginosa (10 µM inhibited more than 50% of growth after 16 h cultivation). Moreover, we could show for the first time that tyrosol strongly inhibits the production of the virulence factors hemolysin and protease in P. aeruginosa, whereas farnesol inhibits, to lower extent, hemolysin production in this bacterial pathogen. Cumulatively, tyrosol is expected to strongly affect P. aeruginosa in mixed microbial biofilm.

  19. Draft Genome Sequence of Microcystis aeruginosa CACIAM 03, a Cyanobacterium Isolated from an Amazonian Freshwater Environment

    PubMed Central

    Castro, Wendel Oliveira; Lima, Alex Ranieri Jerônimo; Moraes, Pablo Henrique Gonçalves; Siqueira, Andrei Santos; Aguiar, Délia Cristina Figueira; Baraúna, Anna Rafaella Ferreira; Martins, Luisa Carício; Fuzii, Hellen Thais; de Lima, Clayton Pereira Silva; Vianez-Júnior, João Lídio Silva Gonçalves; Nunes, Márcio Roberto Teixeira; Dall'Agnol, Leonardo Teixeira

    2016-01-01

    Given its toxigenic potential, Microcystis aeruginosa is an important bloom-forming cyanobacterium. Here, we present a draft genome and annotation of the strain CACIAM 03, which was isolated from an Amazonian freshwater environment. PMID:27856592

  20. Phenotypic and genotypic diversity of Pseudomonas aeruginosa strains isolated from hospitals in siedlce (Poland)

    PubMed Central

    Wolska, Katarzyna; Kot, Barbara; Jakubczak, Antoni

    2012-01-01

    A total of 62 Pseudomonas aeruginosa strains isolated from two hospitals in Siedlce (Poland) were studied by repetitive element based PCR (rep-PCR) using BOX primer. BOX-PCR results revealed the presence of 7 numerous genotypes and 31 unique patterns among isolates. Generally, the strains of P. aeruginosa were characterized by resistance to many antibiotics tested and by differences in serogroups and types of growth on cetrimide agar medium. However, the P. aeruginosa strains isolated from faeces showed much lower phenotypic and genotypic variations in comparison with strains obtained from other clinical specimens. It was observed that genetic techniques supported by phenotypic tests have enabled to conduct a detailed characterization of P. aeruginosa strains isolated from a particular environment at a particular time. PMID:24031829

  1. SERS detection of the biomarker hydrogen cyanide from Pseudomonas aeruginosa cultures isolated from cystic fibrosis patients

    PubMed Central

    Lauridsen, Rikke Kragh; Sommer, Lea M.; Johansen, Helle Krogh; Rindzevicius, Tomas; Molin, Søren; Jelsbak, Lars; Engelsen, Søren Balling; Boisen, Anja

    2017-01-01

    Pseudomonas aeruginosa is the primary cause of chronic airway infections in cystic fibrosis (CF) patients. Persistent infections are seen from the first P. aeruginosa culture in about 75% of young CF patients, and it is important to discover new ways to detect P. aeruginosa at an earlier stage. The P. aeruginosa biomarker hydrogen cyanide (HCN) contains a triple bond, which is utilized in this study because of the resulting characteristic C≡N peak at 2135 cm−1 in a Raman spectrum. The Raman signal was enhanced by surface-enhanced Raman spectroscopy (SERS) on a Au-coated SERS substrate. After long-term infection, a mutation in the patho-adaptive lasR gene can alter the expression of HCN, which is why it is sometimes not possible to detect HCN in the breath of chronically infected patients. Four P. aeruginosa reference strains and 12 clinical P. aeruginosa strains isolated from CF children were evaluated, and HCN was clearly detected from overnight cultures of all wild type-like isolates and half of the later isolates from the same patients. The clinical impact could be that P. aeruginosa infections could be detected at an earlier stage, because daily breath sampling with an immediate output could be possible with a point-of-care SERS device. PMID:28349938

  2. SERS detection of the biomarker hydrogen cyanide from Pseudomonas aeruginosa cultures isolated from cystic fibrosis patients

    NASA Astrophysics Data System (ADS)

    Lauridsen, Rikke Kragh; Sommer, Lea M.; Johansen, Helle Krogh; Rindzevicius, Tomas; Molin, Søren; Jelsbak, Lars; Engelsen, Søren Balling; Boisen, Anja

    2017-03-01

    Pseudomonas aeruginosa is the primary cause of chronic airway infections in cystic fibrosis (CF) patients. Persistent infections are seen from the first P. aeruginosa culture in about 75% of young CF patients, and it is important to discover new ways to detect P. aeruginosa at an earlier stage. The P. aeruginosa biomarker hydrogen cyanide (HCN) contains a triple bond, which is utilized in this study because of the resulting characteristic C≡N peak at 2135 cm-1 in a Raman spectrum. The Raman signal was enhanced by surface-enhanced Raman spectroscopy (SERS) on a Au-coated SERS substrate. After long-term infection, a mutation in the patho-adaptive lasR gene can alter the expression of HCN, which is why it is sometimes not possible to detect HCN in the breath of chronically infected patients. Four P. aeruginosa reference strains and 12 clinical P. aeruginosa strains isolated from CF children were evaluated, and HCN was clearly detected from overnight cultures of all wild type-like isolates and half of the later isolates from the same patients. The clinical impact could be that P. aeruginosa infections could be detected at an earlier stage, because daily breath sampling with an immediate output could be possible with a point-of-care SERS device.

  3. Pseudomonas aeruginosa isolates in severe chronic obstructive pulmonary disease: characterization and risk factors

    PubMed Central

    2014-01-01

    Background Patients with severe chronic obstructive pulmonary disease (COPD) are at increased risk of infection by P. aeruginosa. The specific role of bronchiectasis in both infection and chronic colonization by this microorganism in COPD, however, remains ill defined. To evaluate the prevalence and risk factors for P. aeruginosa recovery from sputum in outpatients with severe COPD, characterizing P. aeruginosa isolates by pulsed-field gel electrophoresis (PFGE) and focusing on the influence of bronchiectasis on chronic colonization in these patients. Methods A case-cohort study of 118 patients with severe COPD attended at a Respiratory Day Unit for an acute infectious exacerbation and followed up over one year. High-resolution CT scans were performed during stability for bronchiectasis assessment and sputum cultures were obtained during exacerbation and stability in all patients. P. aeruginosa isolates were genotyped by PFGE. Determinants of the recovery of P. aeruginosa in sputum and chronic colonization by this microorganism were assessed by multivariate analysis. Results P. aeruginosa was isolated from 41 of the 118 patients studied (34.7%). Five of these 41 patients (12.2%) with P. aeruginosa recovery fulfilled criteria for chronic colonization. In the multivariate analysis, the extent of bronchiectasis (OR 9.8, 95% CI: 1.7 to 54.8) and the number of antibiotic courses (OR 1.7, 95% CI: 1.1 to 2.5) were independently associated with an increased risk of P. aeruginosa isolation. Chronic colonization was unrelated to the presence of bronchiectasis (p=0.75). In patients with chronic colonization the isolates of P. aeruginosa retrieved corresponded to the same clones during the follow-up, and most of the multidrug resistant isolates (19/21) were harbored by these patients. Conclusions The main risk factors for P. aeruginosa isolation in severe COPD were the extent of bronchiectasis and exposure to antibiotics. Over 10% of these patients fulfilled criteria for

  4. Characterization of Toxin-Antitoxin (TA) Systems in Pseudomonas aeruginosa Clinical Isolates in Iran

    PubMed Central

    Savari, Mohammad; Rostami, Soodabeh; Ekrami, Alireza; Bahador, Abbas

    2016-01-01

    Background: Pseudomonas aeruginosa is among the most problematic hospital and community-acquired pathogens. Toxin-antitoxin (TA) systems are maintenance regulatory systems in bacteria and have recently been considered new targets for antimicrobial therapy. The prevalence and transcription of these systems in clinical isolates are still unknown. Objectives: The aim of this study was to characterize three types of TA systems (parDE, relBE, and higBA) among P. aeruginosa clinical isolates. Materials and Methods: We typed our clinical isolates by ERIC-PCR (enterobacterial repetitive intergenic consensus sequence-based polymerase chain reaction) and BOX-PCR. We then investigated 174 P. aeruginosa clinical isolates from three hospitals in Ahvaz, Iran, for the presence of TA system genes, and determined whether these systems were encoded on chromosomes or plasmids by amplification of the flanking regions. Results: Our results showed that in the 174 P. aeruginosa isolates, relBE and higBA were universal, but parDE was less prevalent. Both of the flanking regions of the parDE genes in all positive isolates were amplified. The flanking regions of nearly all relBE genes were amplified. Amplification was observed for the downstream sequence of every higBA locus, as well as for the region upstream of higBA, except in 14 strains. Conclusions: Based on the presence of TA systems in the majority of P. aeruginosa isolates, these could be used as a novel target for antimicrobial therapy. PMID:27099681

  5. Honey as an Antimicrobial Agent Against Pseudomonas Aeruginosa Isolated from Infected Wounds

    PubMed Central

    Shenoy, Vishnu Prasad; Ballal, Mamatha; Shivananda, PG; Bairy, Indira

    2012-01-01

    Background: As natural products garner attention in the medical field due to emergence of antibiotic resistant strains of bacteria, honey is valued for its antibacterial activity. Objective: Fifty strains of Pseudomonas aeruginosa isolated from infected wounds were evaluated for their antibacterial action using honey in comparison with different antibiotics and Dettol. Methodology and Results: All the strains were found to be sensitive to honey at a minimum inhibitory concentration of 20% in comparison with Dettol at 10% using agar dilution method. In the second step, the time kill assay was performed on five isolates of P. aeruginosa to demonstrate the bactericidal activity of honey at different dilutions of honey ranging from 20% to 100% at regular time intervals. All the isolates of P. aeruginosa tested were killed in 12-24 h depending on the dilutions of the honey tested. Thus, honey could prevent the growth of P. aeruginosa even if it was diluted by deionized water by fivefolds in vitro. Honey had almost uniform bactericidal activity against P. aeruginosa irrespective of their susceptibility to different classes of antibiotics. Conclusion: Honey which is a natural, non-toxic, and an inexpensive product has activity against the P. aeruginosa isolated from infected wounds may make it an alternative topical choice in the treatment of wound infections. PMID:22754244

  6. Drug Resistance of Pseudomonas aeruginosa and Enterobacter cloacae Isolated from ICU, Babol, Northern Iran

    PubMed Central

    Bayani, Masoomeh; Siadati, Sepideh; Rajabnia, Ramzan; Taher, Ali Asghar

    2013-01-01

    Multidrug resistant (MDR) bacteria are spread throughout the world which causes nosocomial infections, especially in Intensive Care Unit (ICU). This study aimed to investigate the resistance pattern of Pseudomonas aeruginosa and Enterobacter cloacae isolated from patients in the ICU. During 2011-2012, 30 isolates for each P. aeruginosa and E. cloacae were collected from the patients who acquired nosocomial infection after admition to the ICU at the hospitals affiliated to Babol University of Medical Sciences, Babol, northern Iran. Antimicrobial susceptibility test was performed for five category antibiotics by microdilution method. The data were analyzed by SPSS version 20 and p<0.05 was considered statistically significant. The highest resistance rate of P. aeruginosa was seen to amikacin (53.3%) followed by ceftazidime (43.3%). Also, 16.7% of E. cloacae was resistant to ceftazidime. Among P. aeruginosa isolates,18 (60%) were MDR while no E. cloacae isolates were MDR. The significant correlation was only demonstrated between MDR P. aeruginosa and the reason of hospitalization (P=0.004). In conclusion, there was alarming amount of P. aeruginosa MDR in patients in the ICU which could lead to a hazardous outcome for the patients. Therefore, new prevention policies regarding to hospital infection should be established. Also, the periodical assessment of bacterial resistance pattern particularly in ICUs should be performed. PMID:24551814

  7. Determination of carbapenem resistance mechanism in clinical isolates of Pseudomonas aeruginosa isolated from burn patients, in Tehran, Iran.

    PubMed

    Mirsalehian, Akbar; Kalantar-Neyestanaki, Davood; Taherikalani, Morovat; Jabalameli, Fereshteh; Emaneini, Mohammad

    2017-09-01

    Carbapenems are the most important therapeutic options that effect against serious infections caused by multidrug resistant Pseudomonas aeruginosa (MDR-PA) isolates. Carbapenems resistant isolates of P. aeruginosa are increasing worldwide. The aim of this study was to determine the carbapenem resistance mechanisms in clinical P. aeruginosa isolates from burn patients, in Tehran, Iran. A total of 53 non-duplicated isolates of carbapenem-resistant P. aeruginosa were collected from burn patients. The presence of carbapenemase genes were determined by PCR. AmpC overproducer isolates were detected by phenotypic method. The mutation and transcription level of oprD were determined by PCR-sequencing and quantitative Real-time PCR (RT-PCR), respectively. Twenty-seven (50.9%) isolates were positive for carbapenemase (blaVIM=25 and blaIMP=2) and showed high-level resistance to imipenem and meropenem. Twenty-eight isolates were AmpC overproducers. All isolates had a mutation in the oprD gene and down-regulation of oprD was found in 56.6% of MDR-PA isolates. Although the presence of carbapenemase is the common mechanism of resistant to carbapenem, but carbapenem resistance was found by oprD mutation-driven and the AmpC overproducing isolates in Tehran, Iran. Copyright © 2017 Ministry of Health, Saudi Arabia. Published by Elsevier Ltd. All rights reserved.

  8. Characterization of bacteriophages infecting clinical isolates of Pseudomonas aeruginosa stored in a culture collection

    PubMed Central

    Zanetti, C.C.S.; Mingrone, R.C.C.; Kisielius, J.J.; Ueda-Ito, M.; Pignatari, A.C.C.

    2013-01-01

    Some clinical isolates of Pseudomonas aeruginosa stored in our culture collection did not grow or grew poorly and showed lysis on the culture plates when removed from the collection and inoculated on MacConkey agar. One hypothesis was that bacteriophages had infected and killed those clinical isolates. To check the best storage conditions to maintain viable P. aeruginosa for a longer time, clinical isolates were stored at various temperatures and were grown monthly. We investigated the presence of phage in 10 clinical isolates of P. aeruginosa stored in our culture collection. Four strains of P. aeruginosa were infected by phages that were characterized by electron microscopy and isolated to assess their ability to infect. The best condition to maintain the viability of the strains during storage was in water at room temperature. Three Siphoviridae and two Myoviridae phages were visualized and characterized by morphology. We confirmed the presence of bacteriophages infecting clinical isolates, and their ability to infect and lyse alternative hosts. Strain PAO1, however, did not show lysis to any phage. Mucoid and multidrug resistant strains of P. aeruginosa showed lysis to 50% of the phages tested. PMID:23969975

  9. Use of the paraffin wax baiting system for identification of Pseudomonas aeruginosa clinical isolates.

    PubMed

    Massengale, A R; Ollar, R A; Giordano, S J; Felder, M S; Aronoff, S C

    1999-11-01

    Pseudomonas aeruginosa is the primary pathogen among the Pseudomonads and is known for its minimal nutritional requirements, capacity to use paraffin as a sole carbon source, and biofilm formation. Because the ability of Pseudomonads to grow on paraffin is not commonly found among human pathogens and the primary Pseudomonas human pathogen is P. aeruginosa, we studied the adaptation of the paraffin baiting system for the growth and identification of clinical isolates of P. aeruginosa. We also studied the effectiveness of combining a fluorescence assay measuring fluorescein (pyoverdin) production and oxidase test with the paraffin baiting assay for P. aeruginosa speciation. Strains were tested for the capacity to use paraffin as a sole carbon source using the paraffin baiting system with Czapek's minimal salt medium. Of 111 P. aeruginosa clinical isolates tested for using paraffin as a sole carbon source, 45% exhibited growth on paraffin at 24 h and 76.6% exhibited growth on paraffin at 48 h. The ability of the reference strains and clinical isolates were then tested for their ability to associate with the paraffin slide in the presence of an additional carbon source. Of 111 P. aeruginosa clinical isolates tested, 85 strains (76.6%), and 102 (93%) were associated with the paraffin surface at 24 and 48 h. We successfully combined fluorescence and oxidase assays with the paraffin baiting system for identification of P. aeruginosa. The simple and inexpensive paraffin baiting system is a useful method for the identification and study of P. aeruginosa suitable for both the clinical and research laboratory.

  10. Antibiotic Tolerance Induced by Lactoferrin in Clinical Pseudomonas aeruginosa Isolates from Cystic Fibrosis Patients

    PubMed Central

    Andrés, María T.; Viejo-Diaz, Mónica; Pérez, Francisco; Fierro, José F.

    2005-01-01

    Lactoferrin-induced cell depolarization and a delayed tobramycin-killing effect on Pseudomonas aeruginosa cells were correlated. This antibiotic tolerance effect (ATE) reflects the ability of a defense protein to modify the activity of an antibiotic as a result of its modulatory effect on bacterial physiology. P. aeruginosa isolates from cystic fibrosis patients showed higher ATE values (≤6-fold) than other clinical strains. PMID:15793153

  11. Molecular detection of virulence genes as markers in Pseudomonas aeruginosa isolated from urinary tract infections.

    PubMed

    Sabharwal, Neha; Dhall, Shriya; Chhibber, Sanjay; Harjai, Kusum

    2014-01-01

    Catheter associated urinary tract infections by P. aeruginosa are related to variety of complications. Quorum sensing and related circuitry guard its virulence potential. Though P. aeruginosa accounts for an appreciable amount of virulence factors, this organism is highly unstable phenotypically. Thus, genotyping of clinical isolates of P. aeruginosa is of utmost importance for understanding the epidemiology of infection. This may contribute towards development of immunotherapeutic approaches against this multi drug resistant pathogen. Moreover, no epidemiological study has been reported yet on uroisolates of P. aeruginosa. Thus this study was planned to obtain information regarding presence, distribution and rate of occurrence of quorum sensing and some associated virulence genes at genetic level. The profiling of quorum sensing genes lasI, lasR, rhlI, rhlR and virulence genes like toxA, aprA, rhlAB, plcH, lasB and fliC of twelve strains of P. aeruginosa isolated from patients with UTIs was done by direct PCR. The results showed variable distribution of quorum sensing genes and virulence genes. Their percentage occurrence may be specifically associated with different levels of intrinsic virulence and pathogenicity in urinary tract. Such information can help in identifying these virulence genes as useful diagnostic markers for clinical P. aeruginosa strains isolated from UTIs.

  12. ERIC-PCR genotyping of Pseudomonas aeruginosa isolates from haemorrhagic pneumonia cases in mink.

    PubMed

    Han, Ming-Ming; Mu, Lian-Zhi; Liu, Xu-Ping; Zhao, Jing; Liu, Xiao-Fei; Liu, Hui

    2014-01-01

    Pseudomonas aeruginosa is a significant pathogen of mink and the cause of haemorrhagic pneumonia, an acute fatal disease in farmed mink. Among 90 P. aeruginosa isolates from haemorrhagic pneumonia in mink from 16 farms in Shandong province, China, 43 genotypes were identified by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR), with a diversity index of 0.96. The most prevalent ERIC-PCR types were type 18, found in 16 isolates, and type 39, found in 15 isolates. Four serotypes were detected, with serotype G (55.6 per cent) being the most frequent. These results showed that there was a high degree of clonal diversity among mink P. aeruginosa clinical isolates in this study.

  13. ERIC-PCR genotyping of Pseudomonas aeruginosa isolates from haemorrhagic pneumonia cases in mink

    PubMed Central

    Han, Ming-ming; Mu, Lian-zhi; Liu, Xu-ping; Zhao, Jing; Liu, Xiao-fei; Liu, Hui

    2014-01-01

    Background Pseudomonas aeruginosa is a significant pathogen of mink and the cause of haemorrhagic pneumonia, an acute fatal disease in farmed mink. Results Among 90 P. aeruginosa isolates from haemorrhagic pneumonia in mink from 16 farms in Shandong province, China, 43 genotypes were identified by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR), with a diversity index of 0.96. The most prevalent ERIC-PCR types were type 18, found in 16 isolates, and type 39, found in 15 isolates. Four serotypes were detected, with serotype G (55.6 per cent) being the most frequent. Conclusions These results showed that there was a high degree of clonal diversity among mink P. aeruginosa clinical isolates in this study. PMID:26392878

  14. Simultaneous production of rhamnolipids, 2-alkyl-4-hydroxyquinolines, and phenazines by clinical isolates of Pseudomonas aeruginosa.

    PubMed Central

    Smeal, B C; Bender, L; Jungkind, D L; Hastie, A T

    1987-01-01

    Of 72 clinical isolates of Pseudomonas aeruginosa examined for simultaneous production of secondary metabolites, 86% produced 2-alkyl-4-hydroxyquinolines, 75% produced rhamnolipids, and 58% produced phenazines, including pyocyanin. Whereas isolates producing two or one constituted smaller groups, 39% released all three metabolites. Metabolite production did not appear to influence site of infection. PMID:3112182

  15. Genetic characterization of Microcystis aeruginosa isolates from Portuguese freshwater systems.

    PubMed

    Moreira, Cristiana; Vasconcelos, Vitor; Antunes, Agostinho

    2016-07-01

    Cyanobacteria are microorganisms that pose a serious threat to the aquatic waterways through the production of dense blooms under eutrophic conditions and the release of toxic secondary metabolites-cyanotoxins. Within cyanobacteria, the colonial planktonic Microcystis aeruginosa is widely distributed in both fresh and brackish aquatic environments throughout the world being frequently observed in the Portuguese water systems. Apart from the well-established distribution of M. aeruginosa in Portugal, knowledge of its genetic diversity and population structure is unknown. Therefore, in this study twenty-seven strains were obtained from the North, Centre and South regions of Portugal and were subjected to extensive phylogenetic analyses using simultaneously four distinct genetic markers (16S rRNA, 16S-23S ITS, DNA gyrase subunit ß and cell division protein (ftsZ)) encompassing in total 2834 bp. With this work we characterized the phylogenetic relationship among the Portuguese strains, with the southern strains showing higher genetic structure relatively to the North and Centre strains. A total of fifteen genotypes were determined for M. aeruginosa in Portuguese water systems revealing a high genetic diversity. This is also the first study to report geographic variation on the population structure of the Portuguese M. aeruginosa.

  16. Photodynamic antimicrobial therapy to inhibit pseudomonas aeruginosa of corneal isolates (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Durkee, Heather A.; Relhan, Nidhi; Arboleda, Alejandro; Halili, Francisco; De Freitas, Carolina; Alawa, Karam; Aguilar, Mariela C.; Amescua, Guillermo; Miller, Darlene; Parel, Jean-Marie

    2016-03-01

    Keratitis associated with Pseudomonas aeruginosa is difficult to manage. Treatment includes antibiotic eye drops, however, some strains of Pseudomonas aeruginosa are resistant. Current research efforts are focused on finding alternative and adjunct therapies to treat multi-drug resistant bacteria. One promising alternate technique is photodynamic therapy (PDT). The purpose of this study was to evaluate the effect of riboflavin- and rose bengal-mediated PDT on Pseudomonas aeruginosa keratitis isolates in vitro. Two isolates (S+U- and S-U+) of Pseudomonas aeruginosa were derived from keratitis patients and exposed to five experimental groups: (1) Control (dark, UV-A irradiation, 525nm irradiation); (2) 0.1% riboflavin (dark, UV-A irradiation); and (3) 0.1% rose bengal, (4) 0.05% rose bengal and (5) 0.01% rose bengal (dark, 525nm irradiation). Three days after treatment, in dark conditions of all concentration of riboflavin and rose bengal showed no inhibition in both S+U- and S-U+ strains of Pseudomonas aeruginosa. In 0.1% and 0.05% rose bengal irradiated groups, for both S+U- and S-U+ strains, there was complete inhibition of bacterial growth in the central 50mm zone corresponding to the diameter of the green light source. These in vitro results suggest that rose bengal photodynamic therapy may be an effective adjunct treatment for Pseudomonas aeruginosa keratitis.

  17. Isolation, sequencing and overproduction of the single-stranded DNA binding protein from Pseudomonas aeruginosa PAO.

    PubMed

    Genschel, J; Litz, L; Thole, H; Roemling, U; Urbanke, C

    1996-12-05

    The gene (ssb) encoding the single-stranded DNA binding (SSB) protein from Pseudomonas aeruginosa PAO was detected on a 2.1 kbp PstI-fragment of chromosomal DNA. The protein (PaeSSB) encoded by this gene consists of 165 aa and has a M(r) of 18549. The genomic sequence was confirmed by amino acid sequencing of the amino terminus of SSB protein isolated from P. aeruginosa PAO. PaeSSB shows 68% homology to the respective protein of E. coli. The nucleotide sequence upstream of the P. aeruginosa ssb gene shows little homology to the regulatory region upstream of the ssb gene of E. coli. The ssb gene was located at a distance of 690-870 kbp from the origin of replication on a physical map of P. aeruginosa PAO. In vivo PaeSSB could replace the SSB protein of E. coli (EcoSSB) if its production was controlled by the lac promoter on a high-copy vector. PaeSSB was overproduced in E. coli. Both the overproduced protein and PaeSSB isolated from Pseudomonas aeruginosa PAO are post-translationally modified by cleavage of the first methionine. Analytical ultracentrifugation shows that PaeSSB is a stable homotetramer. The copy number of PaeSSB in P. aeruginosa is 1200 +/- 250 tetramers per cell. Preliminary characterization of the DNA binding properties shows PaeSSB to have a lower affinity for single-stranded DNA than EcoSSB.

  18. Multidrug resistance in Pseudomonas aeruginosa isolated from nosocomial respiratory and urinary infections in Aleppo, Syria.

    PubMed

    Mahfoud, Maysa; Al Najjar, Mona; Hamzeh, Abdul Rezzak

    2015-02-19

    Pseudomonas aeruginosa represents a serious clinical challenge due to its frequent involvement in nosocomial infections and its tendency towards multidrug resistance. This study uncovered antibiotic susceptibility patterns in 177 isolates from inpatients in three key hospitals in Aleppo, the largest city in Syria. Exceptionally low susceptibility to most routinely used antibiotics was uncovered; resistance to ciprofloxacin and gentamicin was 64.9% and 70.3%, respectively. Contrarily, susceptibility to colistin was the highest (89.1%). Multidrug resistance was rife, found at a rate of 53.67% among studied P. aeruginosa isolates.

  19. Emergence of KPC-2-Producing Pseudomonas aeruginosa Sequence Type 463 Isolates in Hangzhou, China

    PubMed Central

    Hu, Yan-yan; Gu, Dan-xia; Cai, Jia-chang; Zhou, Hong-wei

    2015-01-01

    Thirty-nine Klebsiella pneumoniae carbapenemase (KPC)-producing Pseudomonas aeruginosa isolates, all exhibiting high-level resistance to carbapenems and other β-lactam antibiotics, were isolated in Hangzhou, China. Molecular epidemiology analysis indicated the presence of two dominant clones, namely, clones A and B, both of which belong to sequence type 463 (ST463). A genetic environment analysis demonstrated that both clones harbor an ISKpn8 transposase, blaKPC-2, and an ISKpn6-like transposase. These findings depict the features of clonal expansion and transmission of KPC-2-producing P. aeruginosa strains in Hangzhou, China. PMID:25691651

  20. In vitro antimicrobial resistance of Pseudomonas aeruginosa isolated from canine otitis externa in Rio de Janeiro, Brazil

    PubMed Central

    Penna, B.; Thomé, S.; Martins, R.; Martins, G.; Lilenbaum, W.

    2011-01-01

    Isolates of Pseudomonas aeruginosa (167) were obtained from 528 samples of canine otitis externa, identified by biochemical reactions and tested for susceptibility to 10 antimicrobials. The most effective drug was ciprofloxacin. The study reports alarming resistance among P. aeruginosa isolated from canine otitis externa samples in Rio de Janeiro, Brazil. PMID:24031774

  1. Isolation and characterization of quorum-sensing signalling molecules in Pseudomonas aeruginosa isolates recovered from nosocomial infections.

    PubMed

    Lakshmana Gowda, Krishnappa; John, James; Marie, Mohammed A M; Sangeetha, Gopalkrishnan; Bindurani, Shanta Range

    2013-09-01

    Pseudomonas aeruginosa is one of the most common pathogens in nosocomial infections. Many studies have documented the role of quorum-sensing (QS) systems in antibiotic tolerance of P. aeruginosa. N-acyl homoserine lactones (AHLs) serve as QS signalling molecules and can be a target for modulating bacterial pathogenicity. In this study, nosocomial isolates of P. aeruginosa were characterized for the presence of different types of QS signalling molecules. AHLs were solvent extracted and quantified by determination of β-galactosidase activity using the Escherichia coli MG4 reporter strain. Further characterization was performed by analytical thin layer chromatography coupled with detection using the Agrobacterium tumefaciens A136 biosensor strain. All P. aeruginosa isolates produced AHLs, but there were differences in the quantity and nature of AHLs. We identified AHLs belonging to C4-homoserine lactone (HSL), C6-HSL, C8-HSL, C10-HSL and C12-HSL. AHL profiling of P. aeruginosa isolates showed differences in the amounts and types of AHLs, suggesting differences in the virulence factors and the potential for infection. Our results may be investigated further using animal model systems.

  2. Diversity of Molecular Mechanisms Conferring Carbapenem Resistance to Pseudomonas aeruginosa Isolates from Saudi Arabia

    PubMed Central

    Jeannot, Katy; El-Mahdy, Taghrid S.; Samaha, Hassan A.; Shibl, Atef M.; Plésiat, Patrick; Courvalin, Patrice

    2016-01-01

    Background. This study described various molecular and epidemiological characters determining antibiotic resistance patterns in Pseudomonas aeruginosa isolates. Methods. A total of 34 carbapenem-resistant P. aeruginosa clinical isolates were isolated from samples collected at a tertiary hospital in Riyadh, Saudi Arabia, from January to December 2011. Susceptibility testing, serotyping, molecular characterization of carbapenem resistance, and pulsed-field gel electrophoresis (PFGE) were performed. Results. All isolates were resistant to ceftazidime, and more than half were highly resistant (minimum inhibitory concentration (MIC) > 256 mg/L). Fifteen isolates had MIC values ≥64 mg/L for any of the carbapenems examined. Vietnamese extended-spectrum β-lactamase (VEB-1) (n = 16/34) and oxacillinase (OXA-10) (n = 14/34) were the most prevalent extended-spectrum β-lactamase and penicillinase, respectively. Verona imipenemase (VIM-1, VIM-2, VIM-4, VIM-11, and VIM-28) and imipenemase (IMP-7) variants were found in metallo-β-lactamase producers. A decrease in outer membrane porin gene (oprD) expression was seen in nine isolates, and an increase in efflux pump gene (MexAB) expression was detected in five isolates. Six serotypes (O:1, O:4, O:7, O:10, O:11, and O:15) were found among the 34 isolates. The predominant serotype was O:11 (16 isolates), followed by O:15 (nine isolates). PFGE analysis of the 34 carbapenem-resistant P. aeruginosa isolates revealed 14 different pulsotypes. Conclusions. These results revealed diverse mechanisms conferring carbapenem resistance to P. aeruginosa isolates from Saudi Arabia. PMID:27597874

  3. Effect of Tyrosol and Farnesol on Virulence and Antibiotic Resistance of Clinical Isolates of Pseudomonas aeruginosa

    PubMed Central

    Hassan Abdel-Rhman, Shaymaa; Mostafa El-Mahdy, Areej; El-Mowafy, Mohammed

    2015-01-01

    Mixed-species biofilms could create a protected environment that allows for survival to external antimicrobials and allows different bacterial-fungal interactions. Pseudomonas aeruginosa-Candida albicans coexistence is an example for such mixed-species community. Numerous reports demonstrated how P. aeruginosa or its metabolites could influence the growth, morphogenesis, and virulence of C. albicans. In this study, we investigated how the C. albicans quorum sensing compounds, tyrosol and farnesol, might affect Egyptian clinical isolates of P. aeruginosa regarding growth, antibiotic sensitivity, and virulence. We could demonstrate that tyrosol possesses an antibacterial activity against P. aeruginosa (10 µM inhibited more than 50% of growth after 16 h cultivation). Moreover, we could show for the first time that tyrosol strongly inhibits the production of the virulence factors hemolysin and protease in P. aeruginosa, whereas farnesol inhibits, to lower extent, hemolysin production in this bacterial pathogen. Cumulatively, tyrosol is expected to strongly affect P. aeruginosa in mixed microbial biofilm. PMID:26844228

  4. First Detection of Metallo-β-Lactamase VIM-2 in Pseudomonas aeruginosa Isolates from Colombia

    PubMed Central

    Villegas, Maria Virginia; Lolans, Karen; del Rosario Olivera, Maria; Suarez, Carlos José; Correa, Adriana; Queenan, Anne Marie; Quinn, John P.

    2006-01-01

    Carbapenem resistance rates in Pseudomonas aeruginosa isolates in Colombia, as in many South American countries, are high for reasons that remain unclear. From our nationwide network, we describe the first detection of the metallo-β-lactamase VIM-2 in clinical isolates of P. aeruginosa from multiple cities within Colombia. Metallo-β-lactamases were not detected in the two centers with the highest imipenem resistance rates. Clonality was noted in five of the eight centers with strains meeting the criteria for molecular typing. The high carbapenem resistance in P. aeruginosa in Colombia may be attributable to a combination of factors, including the presence of metallo-β-lactamases and nosocomial transmission. PMID:16377690

  5. Activity of Bacteriophages in Removing Biofilms of Pseudomonas aeruginosa Isolates from Chronic Rhinosinusitis Patients

    PubMed Central

    Fong, Stephanie A.; Drilling, Amanda; Morales, Sandra; Cornet, Marjolein E.; Woodworth, Bradford A.; Fokkens, Wytske J.; Psaltis, Alkis J.; Vreugde, Sarah; Wormald, Peter-John

    2017-01-01

    Introduction: Pseudomonas aeruginosa infections are prevalent amongst chronic rhinosinusitis (CRS) sufferers. Many P. aeruginosa strains form biofilms, leading to treatment failure. Lytic bacteriophages (phages) are viruses that infect, replicate within, and lyse bacteria, causing bacterial death. Aim: To assess the activity of a phage cocktail in eradicating biofilms of ex vivo P.aeruginosa isolates from CRS patients. Methods: P. aeruginosa isolates from CRS patients with and without cystic fibrosis (CF) across three continents were multi-locus sequence typed and tested for antibiotic resistance. Biofilms grown in vitro were treated with a cocktail of four phages (CT-PA). Biofilm biomass was measured after 24 and 48 h, using a crystal violet assay. Phage titrations were performed to confirm replication of the phages. A linear mixed effects model was applied to assess the effects of treatment, time, CF status, and multidrug resistance on the biomass of the biofilm. Results: The isolates included 44 strain types. CT-PA treatment significantly reduced biofilm biomass at both 24 and 48 h post-treatment (p < 0.0001), regardless of CF status or antibiotic resistance. Biomass was decreased by a median of 76% at 48 h. Decrease in biofilm was accompanied by a rise in phage titres for all except one strain. Conclusion: A single dose of phages is able to significantly reduce biofilms formed in vitro by a range of P.aeruginosa isolates from CRS patients. This represents an exciting potential and novel targeted treatment for P. aeruginosa biofilm infections and multidrug resistant bacteria. PMID:29018773

  6. Characterization of Virulence Potential of Pseudomonas Aeruginosa Isolated from Bovine Meat, Fresh Fish, and Smoked Fish

    PubMed Central

    Benie, Comoé Koffi Donatien; Dadié, Adjéhi; Guessennd, Nathalie; N’gbesso-Kouadio, Nadège Ahou; Kouame, N’zebo Désiré; N’golo, David Coulibaly; Aka, Solange; Dako, Etienne; Dje, Koffi Marcellin; Dosso, Mireille

    2017-01-01

    Pseudomonas aeruginosa owns a variability of virulence factors. These factors can increase bacterial pathogenicity and infection severity. Despite the importance of knowledge about them, these factors are not more characterized at level of strains derived from local food products. This study aimed to characterize the virulence potential of P. aeruginosa isolated from various animal products. Several structural and virulence genes of P. aeruginosa including lasB, exoS, algD, plcH, pilB, exoU, and nan1 were detected by polymerase chain reaction (PCR) on 204 strains of P. aeruginosa. They were isolated from bovine meat (122), fresh fish (49), and smoked fish (33). The 16S rRNA gene was detected on 91.1% of the presumptive strains as Pseudomonas. The rpoB gene showed that 99.5% of the strains were P. aeruginosa. The lasB gene (89.2%) was the most frequently detected (p < 0.05). In decreasing importance order, exoS (86.8%), algD (72.1%), plcH (72.1%), pilB (40.2%), and exoU (2.5%) were detected. The lasB gene was detected in all strains of P. aeruginosa serogroups O11 and O16. The prevalence of algD, exoS, and exoU genes in these strains varied from 51.2% to 87.4%. The simultaneous determination of serogroups and virulence factors is of interest for the efficacy of surveillance of infections associated with P. aeruginosa. PMID:28386471

  7. Screening of Molecular Virulence Markers in Staphylococcus aureus and Pseudomonas aeruginosa Strains Isolated from Clinical Infections

    PubMed Central

    Cotar, Ani-Ioana; Chifiriuc, Mariana-Carmen; Dinu, Sorin; Bucur, Marcela; Iordache, Carmen; Banu, Otilia; Dracea, Olguta; Larion, Cristina; Lazar, Veronica

    2010-01-01

    Staphylococcus (S.) aureus and Pseudomonas (Ps.) aeruginosa are two of the most frequently opportunistic pathogens isolated in nosocomial infections, responsible for severe infections in immunocompromised hosts. The frequent emergence of antibiotic-resistant S. aureus and Ps. aeruginosa strains has determined the development of new strategies in order to elucidate the different mechanisms used by these bacteria at different stages of the infectious process, providing the scientists with new procedures for preventing, or at least improving, the control of S. aureus and Ps. aeruginosa infections. The purpose of this study was to characterize the molecular markers of virulence in S. aureus and Ps. aeruginosa strains isolated from different clinical specimens. We used multiplex and uniplex PCR assays to detect the genes encoding different cell-wall associated and extracellular virulence factors, in order to evaluate potential associations between the presence of putative virulence genes and the outcome of infections caused by these bacteria. Our results demonstrate that all the studied S. aureus and Ps. aeruginosa strains synthesize the majority of the investigated virulence determinants, probably responsible for different types of infections. PMID:21614207

  8. Activity of AMP2041 against human and animal multidrug resistant Pseudomonas aeruginosa clinical isolates.

    PubMed

    Cabassi, Clotilde Silvia; Sala, Andrea; Santospirito, Davide; Alborali, Giovanni Loris; Carretto, Edoardo; Ghibaudo, Giovanni; Taddei, Simone

    2017-03-23

    Antimicrobial resistance is a growing threat to public health. Pseudomonas aeruginosa is a relevant pathogen causing human and animal infections, frequently displaying high levels of resistance to commonly used antimicrobials. The increasing difficulty to develop new effective antibiotics have discouraged investment in this area and only a few new antibiotics are currently under development. An approach to overcome antibiotic resistance could be based on antimicrobial peptides since they offer advantages over currently used microbicides. The antimicrobial activity of the synthetic peptide AMP2041 was evaluated against 49 P. aeruginosa clinical strains with high levels of antimicrobial resistance, isolated from humans (n = 19) and animals (n = 30). In vitro activity was evaluated by a microdilution assay for lethal dose 90% (LD90), while the activity over time was performed by time-kill assay with 12.5 µg/ml of AMP2014. Evidences for a direct membrane damage were investigated on P. aeruginosa ATCC 27853 reference strain, on animal isolate PA-VET 38 and on human isolate PA-H 24 by propidium iodide and on P. aeruginosa ATCC 27853 by scanning electron microscopy. AMP2041 showed a dose-dependent activity, with a mean (SEM) LD90 of 1.69 and 3.3 µg/ml for animal and human strains, respectively. AMP2041 showed microbicidal activity on P. aeruginosa isolates from a patient with cystic fibrosis (CF) and resistance increased from first infection isolate (LD90 = 0.3 μg/ml) to the mucoid phenotype (LD90 = 10.4 μg/ml). The time-kill assay showed a time-dependent bactericidal effect of AMP2041 and LD90 was reached within 20 min for all the strains. The stain-dead assay showed an increasing of membrane permeabilization and SEM analysis revealed holes, dents and bursts throughout bacterial cell wall after 30 min of incubation with AMP2041. The obtained results assessed for the first time the good antimicrobial activity of AMP2041 on P. aeruginosa strains of

  9. Draft Genome Sequences of Nine Pseudomonas aeruginosa Strains, Including Eight Clinical Isolates

    PubMed Central

    Cunningham, Scott A.; Quest, Daniel; Sikkink, Robert A.; O’Brien, Daniel; Eckloff, Bruce W.; Patel, Robin

    2015-01-01

    We report on nine draft genomes of Pseudomonas aeruginosa isolates, assembled using a hybrid paired-end and Nextera mate-pair library approach. Eight are of clinical origin, and one is the ATCC 27853 strain. We also report their multilocus sequence types. PMID:26450729

  10. Clonal Dissemination of Pseudomonas aeruginosa Isolates Producing Extended-Spectrum β-Lactamase SHV-2a

    PubMed Central

    Jeannot, Katy; Fournier, Damien; Müller, Emeline; Cholley, Pascal

    2013-01-01

    From January to December 2011, 24 Pseudomonas aeruginosa strains producing the extended-spectrum β-lactamase SHV-2a were identified in 13 hospitals in France. With one exception, all the strains belonged to the same clone. Double-disk synergy tests with cefepime and clavulanate were able to detect all the SHV-2a-positive isolates. PMID:23241379

  11. Clonal dissemination of Pseudomonas aeruginosa isolates producing extended-spectrum β-lactamase SHV-2a.

    PubMed

    Jeannot, Katy; Fournier, Damien; Müller, Emeline; Cholley, Pascal; Plésiat, Patrick

    2013-02-01

    From January to December 2011, 24 Pseudomonas aeruginosa strains producing the extended-spectrum β-lactamase SHV-2a were identified in 13 hospitals in France. With one exception, all the strains belonged to the same clone. Double-disk synergy tests with cefepime and clavulanate were able to detect all the SHV-2a-positive isolates.

  12. Draft Genome Sequence of a Pseudomonas aeruginosa NA04 Bacterium Isolated from an Entomopathogenic Nematode.

    PubMed

    Salgado-Morales, Rosalba; Rivera-Gómez, Nancy; Lozano-Aguirre Beltrán, Luis Fernando; Hernández-Mendoza, Armando; Dantán-González, Edgar

    2017-09-07

    We report the draft genome sequence of Gram-negative bacterium Pseudomonas aeruginosa NA04, isolated from the entomopathogenic nematode Heterorhabditis indica MOR03. The draft genome consists of 54 contigs, a length of 6.37 Mb, and a G+C content 66.49%. Copyright © 2017 Salgado-Morales et al.

  13. [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.

  14. Epidemiological markers for Pseudomonas aeruginosa. 5. Subdivision by interative numerical analysis of isolates according to lysotypes.

    PubMed

    Bergan, T; Niemelä, T; Gyllenberg, H

    1975-06-01

    A computer-based numerical approach to the allocation of Pseudomonas aeruginosa bacteriphage patterns has been presented. This rendered a usefule identification of similar phage types. The grouping had epidemiological relevance. Grouping of phage typing patterns of P. aeruginosa by numerical analysis showed that the patterns of related isolations may differ in one strong lysotype reaction, occasionally even in more reactions. Thus parallels previous findings which have been based on studies of the reproducibility of the method and evaluations of differences in epidemiologically related strains from the same sources.

  15. Biofilm Formation and Virulence Factors Among Pseudomonas aeruginosa Isolated From Burn Patients

    PubMed Central

    Ghanbarzadeh Corehtash, Zahra; Khorshidi, Ahmad; Firoozeh, Farzaneh; Akbari, Hosein; Mahmoudi Aznaveh, Azam

    2015-01-01

    Background: Pseudomonas aeruginosa possesses a variety of virulence factors and infections caused by multidrug-resistant P. aeruginosa (MDRPA) in burn patients are a public health problem. Objectives: The aim of this study was to determine the antibiotic resistance pattern, the biofilm formation, the prevalence of MDRPA and two virulence genes (nan1 and exoA) among P. aeruginosa isolated from burn patients. Patients and Methods: A total of 144 isolates of P. aeruginosa were collected from burn patient at the Burn Centre of Tehran, Iran, between March 2013 and July 2013. Antibiotic susceptibility test was performed via agar disk diffusion method. The ability of producing biofilm was examined by crystal violet microtiter plate assay and the prevalence of the exoA and nan1 genes among the isolates was determined by polymerase chain reaction (PCR). Results: A high rate of resistance was seen against ciprofloxacin (93.7%), aztreonam (86.8%), piperacillin (85.4%), ceftazidime (82.6%), amikacin (82%) and imipenem (79.2%). In total, 93.1% of the isolates were characterized as MDRPA. Biofilm formation was seen in 92.4% of the isolates. The prevalence of the exoA and nan1 genes were 75% and 11.8% among the isolates, respectively. Conclusions: The high rate of MDRPA and its ability to produce biofilm is an alarm for public health. The statistical analysis showed that biofilm production in the MDRPA isolates was significantly higher than that in the non–MDRPA isolates (P < 0.001). PMID:26587205

  16. [Characterization of isolates of carbapenemase-producing Pseudomonas aeruginosa from seven Colombian provinces].

    PubMed

    Saavedra, Sandra Yamile; Duarte, Carolina; González, María Nilse; Realpe, María Elena

    2014-04-01

    Pseudomonas aeruginosa is an opportunistic pathogen that causes multiple infections in hospitalized patients. This microorganism has developed resistance to several antimicrobial agents, including carbapenems, which are considered to be the last therapeutic option against these infections. Carbapenem resistance of P. aeruginosa is mediated by different mechanisms: Carbapenemases class B (MBL) and A, alterations in the OprD expression and overexpression of the Mex efflux pump. To describe the presence of carbapenemases in P. aeruginosa isolates from seven Colombian provinces. A total of 57 P. aeruginosa isolates were collected between September 2012 and March 2013 from national surveillance in Colombia and were sent to the Grupo de Microbiología at the Instituto Nacional de Salud (INS) for evaluation. Iidentification and antimicrobial susceptibility were confirmed through automated method (Vitek ® 2) and disk diffusion (Kirby-Bauer) according to the Clinical and Laboratory Standards Institute, CLSI, 2013. Phenotypic and genotypic confirmation was determined using the modified Hodge test (MHT), a synergism test using imipenem, EDTA-SMA and meropenem, and conventional PCR to detect the bla KPC, bla VIM, bla IMP and bla NDM genes. Of the 57 isolates, two showed sensitivity to carbapenems. Forty-three isolates were positive for carbapenemases with a high percentage of sensitivity to colistin (76.4%, n=42). The 43 isolates producing carbapenemases showed multiple drug resistance: 72.1% were positive in the MHT and 79.1% showed MBL synergism. PCR amplification confirmed that 33 isolates were positive for bla VIM, nine were positive for bla KPC and one isolate expressed both KPC and VIM carbapenemases. No isolates showed amplified products with bla IMP and bla NDM primers. The most frequent carbapenemase was VIM, followed by KPC in an approximate ratio of 3:1.

  17. Isolation of Pseudomonas aeruginosa from cockroaches Captured in hospitals in Japan, and their antibiotic susceptibility.

    PubMed

    Saitou, Keiko; Furuhata, Katsunori; Kawakami, Yasushi; Fukuyama, Masafumi

    2009-12-01

    Pseudomonas aeruginosa strains were isolated from 45 of 370 (12.2%) cockroaches captured in hospitals. By cockroach species, the bacterial strains were isolated from 39 of 181 (21.5%) Periplaneta fuliginosa and 6 of 183 (3.3%) Blattella germanica, showing a significant difference (p<0.01). Many P. aeruginosa-carrying cockroaches inhabited locker rooms (66.7%) and kitchens (17.8%). In terms of serotyping, many isolates were typed into groups A, G, and B. In drug sensitivity tests, strains showed the highest sensitivity to ciprofloxacin with an MIC90 of 0.25 microg/ml, followed by 2 microg/ml meropenem, and 4 microg/ml ceftazidime, gentamicin, and ofloxacin. In contrast, many strains were resistant to cefotaxime and minocycline, accounting for 86.7% of all resistant strains. However, there was no multidrug-resistant P. aeruginosa strain, and all strains were negative for the metallo-beta-lactamase gene (IMP-1 and VIM-2). These findings suggested that cockroach-derived P. aeruginosa may contaminate hospital environments, for which the control of disease-carrying insects in hospitals is important.

  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. Genetic diversity of clinical Pseudomonas aeruginosa isolates in a public hospital in Spain

    PubMed Central

    2013-01-01

    Background Pseudomonas aeruginosa is an important nosocomial pathogen that exhibits multiple resistances to antibiotics with increasing frequency, making patient treatment more difficult. The aim of the study is to ascertain the population structure of this clinical pathogen in the Hospital Son Llàtzer, Spain. Results A significant set (56) of randomly selected clinical P. aeruginosa isolates, including multidrug and non-multidrug resistant isolates, were assigned to sequence types (STs) and compared them with their antibiotic susceptibility profile classified as follows: extensively drug resistant (XDR), multidrug resistant (MDR) and non-multidrug resistant (non-MDR). The genetic diversity was assessed by applying the multilocus sequence typing (MLST) scheme developed by Curran and collaborators, and by the phylogenetic analysis of a concatenated tree. The analysis of seven loci, acsA, aroE, guaA, mutL, nuoD, ppsA and trpE, demonstrated that the prevalent STs were ST-175, ST-235 and ST-253. The majority of the XDR and MDR isolates were included in ST-175 and ST-235. ST-253 is the third in frequency and included non-MDR isolates. The 26 singleton sequence types corresponded mainly to non-MDR isolates. Twenty-two isolates corresponded to new sequence types (not previously defined) of which 12 isolates were non-MDR and 10 isolates were MDR or XDR. Conclusions The population structure of clinical P. aeruginosa present in our hospital indicates the coexistence of nonresistant and resistant isolates with the same sequence type. The multiresistant isolates studied are grouped in the prevalent sequence types found in other Spanish hospitals and at the international level, and the susceptible isolates correspond mainly to singleton sequence types. PMID:23773707

  20. Characterization of Pseudomonas aeruginosa isolates associated with mortality in broiler chicks.

    PubMed

    Walker, S E; Sander, J E; Cline, J L; Helton, J S

    2002-01-01

    In mid-2000, a broiler chicken company in Alabama experienced high early mortality rates in chicks from two different hatcheries. Five isolates of Pseudomonas aeruginosa, obtained from these contaminated hatcheries and resulting broiler chicks with omphalitis, were selected to determine virulence of the bacteria. One-day-old specific-pathogen-free white leghorn chicks were placed into positive pressure isolation units (10 chicks per unit); feed and water were provided ad libitum. The five isolates of P. aeruginosa (1 x 10(1) or 1 x 10(1) colony-forming units/bird) were used to challenge two replicates of 10 chicks via yolk sac inoculation. Two control groups were injected with 0.1 ml of phosphate-buffered saline, and two groups received no treatment. Mortality was recorded daily, and the chicks that died were necropsied and liver and yolk sacs were cultured. After 14 days, the remaining chickens were euthanatized and necropsied. Bacterial isolates retrieved from liver and yolk sacs were identified by the API 20 NE typing system to confirm that they were the same as the challenge isolate. Virulence varied greatly among the isolates, resulting in mortality rates from 0 to 90%. The challenge isolates produced different and often distinctive postmortem lesion patterns. Antibiotic sensitivity tests showed that all five isolates were resistant to sulfisoxazole, ceftiofur, penicillin, lincomycin, bacitracin, oxytetracycline, erythromycin, naladixic acid, and tetracycline. The isolates varied in sensitivity to other antibiotics, but all isolates were sensitive to gentamicin.

  1. Antimicrobial activity of tobramycin against respiratory cystic fibrosis Pseudomonas aeruginosa isolates from Bulgaria.

    PubMed

    Strateva, T; Petrova, G; Mitov, I

    2010-12-01

    Tobramycin solution for inhalation (TSI) (Novartis pharmaceuticals) is indicated as chronic suppressive treatment for cystic fibrosis (CF) patients aged 6 years and older who are chronically infected by Pseudomonas aeruginosa . Inhaled administration of tobramycin assures high concentrations in the lungs of CF patients, improving the therapeutic ratio over that of parenteral tobramycin levels. Clinical and laboratory Standards institute (CLSI) breakpoints only consider parenteral levels and do not take into account these high antimicrobial concentrations. Therefore, the Spanish meNSURA Group has defined specific values for inhaled tobramycin when testing CF P. aeruginosa isolates (susceptible: minimal inhibitory concentration (MIC) ≤ 64 μg/ml; resistant: ≥ 128 μg/ml). In this study the antimicrobial activity of tobramycin against 120 respiratory CF P. aeruginosa isolates was determined by high-range etest strips (LIOFILCHEM). Applying MENSURA breakpoints, 95% of the strains were categorized as susceptible. With CLSI breakpoints, the susceptibility rate decreased to 92.5%. The activity against non-mucoid P. aeruginosa was higher than that against mucoid isolates (MIC(50)=0.75 and MIC(90)=2 μg/ml vs. MIC(50)=1 and MIC(90)=4 μg/ml). The isolates obtained from patients untreated with TSI were more susceptible to the drug than those from patients receiving maintenance therapy with TSI (MIC(50)=0.75 and MIC(90) =1.5 μg/ml vs. MIC(50)=1.5 and MIC(90)=6 μg/ml). The isolates from patients with long-term P. aeruginosa colonization (over 5 years) revealed the highest tobramycin MICs (MIC(50)=1.00 and MIC(90)>1024 μg/ml). In conclusion, tobramycin has excellent in vitro activity against the studied CF isolates. Some factors such as isolate morphotype, pre-administration of TSI and duration of colonization influence its activity. Whenever TSI is considered for therapy, the CF P. aeruginosa strains categorized as intermediate or resistant to tobramycin according to

  2. [Performance evaluation of VITEK 2 system in meropenem susceptibility testing of clinical Pseudomonas aeruginosa isolates].

    PubMed

    Acuner, Ibrahim Cağatay; Bayramoğlu, Gülçin; Birinci, Asuman; Cekiç Cihan, Ciğdem; Bek, Yüksel; Durupınar, Belma

    2011-07-01

    Pseudomonas aeruginosa is an important opportunistic pathogen associated with various community-acquired or nosocomial infections. Multi-drug resistant P.aeruginosa strains increasingly cause epidemics and spread in various hospital wards and geographic regions. Carbapenems are among the most effective antimicrobials in the treatment of multi-drug resistant P.aeruginosa infections, and meropenem is the most successful among alternatives in initial therapy. Particularly in severe infections, inappropriate or inadequate initial antimicrobial therapy is independently associated with adverse clinical and economic outcomes. Availability of accurate and rapid susceptibility testing is a priority. Most of the automated microbiology systems can provide rapid results within 8 to 12 hours. In comparison to standard methods, problems in the antimicrobial susceptibility testing of particular microorganisms and antimicrobial agents have been reported for automated microbiology systems. Failures have been reported previously especially in the susceptibility testing of P.aeruginosa versus carbapenem. Most of these studies are designed according to the Food and Drug Administration (FDA, USA) performance analysis scheme (Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test Systems) in a simplified form. However, there are many lacking issues in the design of most of these studies. Among these, insufficient sample size, use of inappropriate reference method, lack of reproducibility testing, and inadequate distribution of study isolates in interpretative categories are of notice. There are only few studies in the literature that evaluate the performance of automated systems in antimicrobial susceptibility testing of carbapenems in clinical P.aeruginosa isolates with a sufficient sample size (n ? 100). However, most of these studies still have one or more major deficiencies in the study design. Furthermore, none of these studies evaluate the performance of

  3. Dissemination of metallo-β-lactamase in Pseudomonas aeruginosa isolates in Egypt: mutation in blaVIM-4.

    PubMed

    Hashem, Hany; Hanora, Amro; Abdalla, Salah; Shaeky, Alaa; Saad, Alaa

    2017-05-01

    This study was designed to investigate the prevalence of metallo-β-lactamase (MBL) in Pseudomonas aeruginosa isolates collected from Suez Canal University Hospital in Ismailia, Egypt. Antibiotic susceptibility testing and phenotypic and genotypic screening for MBLs were performed on 147 isolates of P. aeruginosa. MICs were determined by agar dilution method for carbapenem that was ≥2 μg/mL for meropenem. MBL genes were detected by multiplex and monoplex PCR for P. aeruginosa-harbored plasmids. Mutation profile of sequenced MBL genes was screened using online software Clustal Omega. Out of 147 P. aeruginosa, 39 (26.5%) were carbapenem-resistant isolates and 25 (64%) were confirmed to be positive for MBLs. The susceptibility rate of P. aeruginosa toward polymyxin B and norfloxacin was 99% and 88%, respectively. Identification of collected isolates by API analysis and constructed phylogenetic tree of 16S rRNA showed that the isolates were related to P. aeruginosa species. The frequency of blaGIM-1, blaSIM-1, and blaSPM-1 was 52%, 48%, and 24%, respectively. BlaVIM and blaIMP-like genes were 20% and 4% and the sequences confirm the isolate to be blaVIM-1, blaVIM-2, blaVIM-4, and blaIMP-1. Three mutations were identified in blaVIM-4 gene. Our study emphasizes the high occurrence of multidrug-resistant P. aeruginosa-producing MBL enzymes. © 2017 APMIS. Published by John Wiley & Sons Ltd.

  4. 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

  5. Evaluating synergy between marbofloxacin and gentamicin in Pseudomonas aeruginosa strains isolated from dogs with otitis externa.

    PubMed

    Jerzsele, Ákos; Pásztiné-Gere, Erzsébet

    2015-03-01

    The aim of this study was to determine antimicrobial susceptibility of Pseudomonas aeruginosa strains to marbofloxacin and gentamicin, and investigate the possible synergistic, additive, indifferent or antagonistic effects between the two agents. P. aeruginosa strains can develop resistance quickly against certain antibiotics if used alone, thus the need emerges to find synergistic combinations. A total of 68 P. aeruginosa strains isolated from dogs were examined. In order to describe interactions between marbofloxacin and gentamicin the checkerboard microdilution method was utilized. The MICs (minimum inhibitory concentrations) for marbofloxacin and gentamicin were in the range 0.25-64 mg/L and 0.25-32 mg/L, respectively. The combination of marbofloxacin and gentamicin was more effective with a MIC range of 0.031-8 mg/L and a MIC90 of 1 mg/L, compared to 16 mg/L for marbofloxacin alone and 8 mg/L for gentamicin alone. The FIC (fractional inhibitory concentration) indices ranged from 0.0945 (pronounced synergy) to 1.0625 (indifference). Synergy between marbofloxacin and gentamicin was found in 33 isolates. The mean FIC index is 0.546, which represents a partial synergistic/additive effect close to the full synergy threshold. In vitro results indicate that marbofloxacin and gentamicin as partially synergistic agents may prove clinically useful in combination therapy against P. aeruginosa infections. Although marbofloxacin is not used in the human practice, the interactions between fluoroquinolones and aminoglycosides may have importance outside the veterinary field.

  6. Genetic features of Pseudomonas aeruginosa isolates from cystic fibrosis patients compared with those of isolates from other origins.

    PubMed

    Lanotte, Philippe; Watt, Stephane; Mereghetti, Laurent; Dartiguelongue, Nathalie; Rastegar-Lari, Aziz; Goudeau, Alain; Quentin, Roland

    2004-01-01

    In order to improve our understanding of the colonization of the pulmonary tract of cystic fibrosis (CF) patients by Pseudomonas aeruginosa, 162 isolates from five different ecological origins were studied. The genetic features of each isolate were determined by random amplification of polymorphic DNA (RAPD) and by searching for eight virulence genes (six known virulence genes, algD, lasB, toxA, plcH, plcN and exoS, and two genes encoding putative neuraminidases, nan1 and nan2). Five RAPD groups were identified. Most of the CF isolates were distributed equally in three of these groups (RA, RB and RC). The CF isolates in RB were related to isolates from a wide variety of origins. The CF isolates in RA were related to a population composed of 65 % of the non-CF isolates from pulmonary tract infections. RC was mainly composed of CF isolates that were related to 30 % of isolates from plants. All genes except exoS and nan1 were present in all isolates. The exoS and nan1 virulence factor genes were most prevalent in CF isolates. exoS, which encodes exoenzyme S, was present in 94 % of CF isolates but also in 80 % of non-CF isolates from pulmonary tract infections. nan1, which encodes a putative neuraminidase, was found in 82.5 % of the isolates from group RC, which was composed largely of CF isolates. In conclusion, three major genogroups of P. aeruginosa isolates, each of which exhibits peculiar genetic features, are able to colonize CF patients. This may have different consequences on the outcome of pulmonary disease.

  7. Carbapenem-resistant and cephalosporin-susceptible: a worrisome phenotype among Pseudomonas aeruginosa clinical isolates in Brazil.

    PubMed

    Campana, Eloiza Helena; Xavier, Danilo Elias; Petrolini, Fernanda Villas-Boas; Cordeiro-Moura, Jhonatha Rodrigo; Araujo, Maria Rita Elmor de; Gales, Ana Cristina

    The mechanisms involved in the uncommon resistance phenotype, carbapenem resistance and broad-spectrum cephalosporin susceptibility, were investigated in 25 Pseudomonas aeruginosa clinical isolates that exhibited this phenotype, which were recovered from three different hospitals located in São Paulo, Brazil. The antimicrobial susceptibility profile was determined by CLSI broth microdilution. β-lactamase-encoding genes were investigated by PCR followed by DNA sequencing. Carbapenem hydrolysis activity was investigated by spectrophotometer and MALDI-TOF assays. The mRNA transcription level of oprD was assessed by qRT-PCR and the outer membrane proteins profile was evaluated by SDS-PAGE. Genetic relationship among P. aeruginosa isolates was assessed by PFGE. Carbapenems hydrolysis was not detected by carbapenemase assay in the carbapenem-resistant and cephalosporin-susceptible P. aueruginosa clinical isolates. OprD decreased expression was observed in all P. aeruginosa isolates by qRT-PCR. The outer membrane protein profile by SDS-PAGE suggested a change in the expression of the 46kDa porin that could correspond to OprD porin. The isolates were clustered into 17 genotypes without predominance of a specific PFGE pattern. These results emphasize the involvement of multiple chromosomal mechanisms in carbapenem-resistance among clinical isolates of P. aeruginosa, alert for adaptation of P. aeruginosa clinical isolates under antimicrobial selective pressure and make aware of the emergence of an uncommon phenotype among P. aeruginosa clinical isolates.

  8. Environmentally Endemic Pseudomonas aeruginosa Strains with Mutations in lasR Are Associated with Increased Disease Severity in Corneal Ulcers

    PubMed Central

    Hammond, John H.; Hebert, Wesley P.; Naimie, Amanda; Ray, Kathryn; Van Gelder, Rachel D.; DiGiandomenico, Antonio; Lalitha, Prajna; Srinivasan, Muthiah; Acharya, Nisha R.; Lietman, Thomas; Hogan, Deborah A.

    2016-01-01

    ABSTRACT The Steroids for Corneal Ulcers Trial (SCUT) was a multicenter, international study of bacterial keratitis in which 101 Pseudomonas aeruginosa infections were treated. Twenty-two of 101 P. aeruginosa isolates collected had a colony morphology characteristic of a loss-of-function mutation in lasR, the gene encoding a quorum-sensing master regulator. Ulcers caused by these 22 strains were associated with larger areas of corneal opacification, worse vision, and a lower rate of vision recovery in response to treatment than ulcers caused by the other isolates. The lasR sequences from these isolates each contained one of three nonsynonymous substitutions, and these strains were deficient in production of LasR-regulated protease and rhamnolipids. Replacement of lasR with either of the two most common lasR alleles from the SCUT isolates was sufficient to decrease protease and rhamnolipid production in PA14. Loss of LasR function is associated with increased production of CupA fimbriae, and the LasR-defective isolates exhibited higher production of CupA fimbriae than LasR-intact isolates. Strains with the same lasR mutation were of the same multilocus sequence type, suggesting that LasR-deficient, environmental P. aeruginosa strains were endemic to the area, and infections caused by these strains were associated with worse patient outcomes in the SCUT study. (This study has been registered at ClinicalTrials.gov under registration no. NCT00324168.) IMPORTANCE The LasR transcription factor is an important regulator of quorum sensing in P. aeruginosa and positively controls multiple virulence-associated pathways. The emergence of strains with lasR loss-of-function alleles in chronic disease is well described and is thought to represent a specific adaptation to the host environment. However, the prevalence and virulence of these strains in acute infections remain unclear. This report describes observations revealing that lasR mutants were common among isolates from

  9. Prevalence, conservation and functional analysis of Yersinia and Escherichia CRISPR regions in clinical Pseudomonas aeruginosa isolates

    PubMed Central

    Cady, K. C.; White, A. S.; Hammond, J. H.; Abendroth, M. D.; Karthikeyan, R. S. G.; Lalitha, P.; Zegans, M. E.; O'Toole, G. A.

    2011-01-01

    Here, we report the characterization of 122 Pseudomonas aeruginosa clinical isolates from three distinct geographical locations: Dartmouth Hitchcock Medical Center in New Hampshire, USA, the Charles T. Campbell Eye Microbiology Lab at the University of Pittsburgh Medical Center, USA, and the Aravind Eye Hospital in Madurai, India. We identified and located clustered regularly interspaced short palindromic repeats (CRISPR) in 45/122 clinical isolates and sequenced these CRISPR, finding that Yersinia subtype CRISPR regions (33 %) were more prevalent than the Escherichia CRISPR region subtype (6 %) in these P. aeruginosa clinical isolates. Further, we observed 132 unique spacers from these 45 CRISPR that are 100 % identical to prophages or sequenced temperate bacteriophage capable of becoming prophages. Most intriguingly, all of these 132 viral spacers matched to temperate bacteriophage/prophages capable of inserting into the host chromosome, but not to extrachromosomally replicating lytic P. aeruginosa bacteriophage. We next assessed the ability of the more prevalent Yersinia subtype CRISPR regions to mediate resistance to bacteriophage infection or lysogeny by deleting the entire CRISPR region from sequenced strain UCBPP-PA14 and six clinical isolates. We found no change in CRISPR-mediated resistance to bacteriophage infection or lysogeny rate even for CRISPR with spacers 100 % identical to a region of the infecting bacteriophage. Lastly, to show these CRISPR and cas genes were expressed and functional, we demonstrated production of small CRISPR RNAs. This work provides both the first examination to our knowledge of CRISPR regions within clinical P. aeruginosa isolates and a collection of defined CRISPR-positive and -negative strains for further CRISPR and cas gene studies. PMID:21081758

  10. Prevalence, conservation and functional analysis of Yersinia and Escherichia CRISPR regions in clinical Pseudomonas aeruginosa isolates.

    PubMed

    Cady, K C; White, A S; Hammond, J H; Abendroth, M D; Karthikeyan, R S G; Lalitha, P; Zegans, M E; O'Toole, G A

    2011-02-01

    Here, we report the characterization of 122 Pseudomonas aeruginosa clinical isolates from three distinct geographical locations: Dartmouth Hitchcock Medical Center in New Hampshire, USA, the Charles T. Campbell Eye Microbiology Lab at the University of Pittsburgh Medical Center, USA, and the Aravind Eye Hospital in Madurai, India. We identified and located clustered regularly interspaced short palindromic repeats (CRISPR) in 45/122 clinical isolates and sequenced these CRISPR, finding that Yersinia subtype CRISPR regions (33 %) were more prevalent than the Escherichia CRISPR region subtype (6 %) in these P. aeruginosa clinical isolates. Further, we observed 132 unique spacers from these 45 CRISPR that are 100 % identical to prophages or sequenced temperate bacteriophage capable of becoming prophages. Most intriguingly, all of these 132 viral spacers matched to temperate bacteriophage/prophages capable of inserting into the host chromosome, but not to extrachromosomally replicating lytic P. aeruginosa bacteriophage. We next assessed the ability of the more prevalent Yersinia subtype CRISPR regions to mediate resistance to bacteriophage infection or lysogeny by deleting the entire CRISPR region from sequenced strain UCBPP-PA14 and six clinical isolates. We found no change in CRISPR-mediated resistance to bacteriophage infection or lysogeny rate even for CRISPR with spacers 100 % identical to a region of the infecting bacteriophage. Lastly, to show these CRISPR and cas genes were expressed and functional, we demonstrated production of small CRISPR RNAs. This work provides both the first examination to our knowledge of CRISPR regions within clinical P. aeruginosa isolates and a collection of defined CRISPR-positive and -negative strains for further CRISPR and cas gene studies.

  11. Molecular characterization of multidrug-resistant (MDR) Pseudomonas aeruginosa isolated in a burn center.

    PubMed

    de Almeida Silva, Keila de Cássia Ferreira; Calomino, Mariana Alcântara; Deutsch, Gabriela; de Castilho, Selma Rodrigues; de Paula, Geraldo Renato; Esper, Luciana Maria Ramires; Teixeira, Lenise Arneiro

    2017-02-01

    The aim of this study was to characterize molecularly multidrug-resistant (MDR) Pseudomonas aeruginosa isolates collected from burn center (BC) patients and environment in a hospital localized in Rio de Janeiro city, RJ, Brazil. Thirty-five P. aeruginosa isolates were studied. The antimicrobial resistance was tested by disk diffusion method as recommended by CLSI. The assessment of virulence (exoS and exoU) and resistance (blaPER-1, blaCTX-M, blaOXA-10, blaGES-1, blaVIM, blaIMP, blaSPM-1, blaKPC, blaNDM and blaSIM) genes were achieved through PCR and biofilm forming capacity was determined using a microtiter plates based-assay, as described previously. Genotyping was performed using Multilocus sequence typing (MLST). High rate of P. aeruginosa (71.4%; 25/35) were classified as MDR, of them 64% (16/25) were related to clone A, the most prevalent clone found in the BC studied. A total of eight carbapenems resistant isolates were detected; three belonging to clone A and five carrying the exoU virulence gene. In addition, clone A isolates were also biofilm producers. Two new sequence types (ST) were detected in this study: ST2236, grouped in to clone A; and ST2237, classified in the different clones, displaying carbapenem resistance and exoU virulence gene. The high prevalence of biofilm producers and multiresistant P. aeruginosa isolates in BC indicates that prevention programs need to be implemented to avoid infection in highly susceptible patients. Copyright © 2016. Published by Elsevier Ltd.

  12. Colistin susceptibility testing: evaluation of reliability for cystic fibrosis isolates of Pseudomonas aeruginosa and Stenotrophomonas maltophilia

    PubMed Central

    Moskowitz, Samuel M.; Garber, Elizabeth; Chen, Yunhua; Clock, Sarah A.; Tabibi, Setareh; Miller, Amanda K.; Doctor, Michael; Saiman, Lisa

    2010-01-01

    Objectives Antibiotic susceptibility methods that are commonly used to test bacterial isolates from patients with cystic fibrosis are of uncertain reliability for the polymyxins. To assess the reliability of four standard testing methods, this pilot study used a challenge set that included polymyxin-resistant isolates of Pseudomonas aeruginosa and Stenotrophomonas maltophilia. Methods Twenty-five P. aeruginosa and 12 S. maltophilia isolates were tested for susceptibility to colistin (polymyxin E). Repeatability (concordance of replicates performed concurrently), reproducibility (concordance of replicates performed over time) and comparability (concordance of different methods) of agar dilution, broth microdilution, Etest and disc diffusion were assessed through the use of descriptive statistics and scatterplot analyses. Results All four methods displayed excellent repeatability (overall concordance rate of 99%). However, analysis of reproducibility revealed substantially lower rates of concordance (74% for agar dilution, 84% for broth microdilution and Etest, and 91% for disc diffusion). In addition, comparability to agar dilution of the three other methods was generally poor, with overall rates of very major error ranging from 12% for broth microdilution to 18% for Etest and disc diffusion. Conclusions Compared with agar dilution, other susceptibility testing methods give high rates of apparent false polymyxin susceptibility for cystic fibrosis isolates of P. aeruginosa and S. maltophilia. Prospective study of the correlation between in vitro susceptibility and clinical response is needed to clarify whether these discrepancies reflect oversensitivity of the agar dilution method or insensitivity of the other methods. PMID:20430789

  13. Isolation and characterization of gallium resistant Pseudomonas aeruginosa mutants.

    PubMed

    García-Contreras, Rodolfo; Lira-Silva, Elizabeth; Jasso-Chávez, Ricardo; Hernández-González, Ismael L; Maeda, Toshinari; Hashimoto, Takahiro; Boogerd, Fred C; Sheng, Lili; Wood, Thomas K; Moreno-Sánchez, Rafael

    2013-12-01

    Pseudomonas aeruginosa PA14 cells resistant to the novel antimicrobial gallium nitrate (Ga) were developed using transposon mutagenesis and by selecting spontaneous mutants. The mutants showing the highest growth in the presence of Ga were selected for further characterization. These mutants showed 4- to 12-fold higher Ga minimal inhibitory growth concentrations and a greater than 8-fold increase in the minimum biofilm eliminating Ga concentration. Both types of mutants produced Ga resistant biofilms whereas the formation of wild-type biofilms was strongly inhibited by Ga. The gene interrupted in the transposon mutant was hitA, which encodes a periplasmic iron binding protein that delivers Fe³⁺ to the HitB iron permease; complementation of the mutant with the hitA gene restored the Ga sensitivity. This hitA mutant showed a 14-fold decrease in Ga internalization versus the wild-type strain, indicating that the HitAB system is also involved in the Ga uptake. Ga uptake in the spontaneous mutant was also lower, although no mutations were found in the hitAB genes. Instead, this mutant harbored 64 non-silent mutations in several genes including those of the phenazine pyocyanin biosynthesis. The spontaneous mutant produced 2-fold higher pyocyanin basal levels than the wild-type; the addition of this phenazine to wild-type cultures protected them from the Ga bacteriostatic effect. The present data indicate that mutations affecting Ga transport and probably pyocyanin biosynthesis enable cells to develop resistance to Ga. Copyright © 2013 Elsevier GmbH. All rights reserved.

  14. Genetically and Phenotypically Distinct Pseudomonas aeruginosa Cystic Fibrosis Isolates Share a Core Proteomic Signature

    PubMed Central

    Penesyan, Anahit; Kumar, Sheemal S.; Kamath, Karthik; Shathili, Abdulrahman M.; Venkatakrishnan, Vignesh; Krisp, Christoph; Packer, Nicolle H.; Molloy, Mark P.; Paulsen, Ian T.

    2015-01-01

    The opportunistic pathogen Pseudomonas aeruginosa is among the main colonizers of the lungs of cystic fibrosis (CF) patients. We have isolated and sequenced several P. aeruginosa isolates from the sputum of CF patients and compared them with each other and with the model strain PAO1. Phenotypic analysis of CF isolates showed significant variability in colonization and virulence-related traits suggesting different strategies for adaptation to the CF lung. Genomic analysis indicated these strains shared a large set of core genes with the standard laboratory strain PAO1, and identified the genetic basis for some of the observed phenotypic differences. Proteomics revealed that in a conventional laboratory medium PAO1 expressed 827 proteins that were absent in the CF isolates while the CF isolates shared a distinctive signature set of 703 proteins not detected in PAO1. PAO1 expressed many transporters for the uptake of organic nutrients and relatively few biosynthetic pathways. Conversely, the CF isolates expressed a narrower range of transporters and a broader set of metabolic pathways for the biosynthesis of amino acids, carbohydrates, nucleotides and polyamines. The proteomic data suggests that in a common laboratory medium PAO1 may transport a diverse set of “ready-made” nutrients from the rich medium, whereas the CF isolates may only utilize a limited number of nutrients from the medium relying mainly on their own metabolism for synthesis of essential nutrients. These variations indicate significant differences between the metabolism and physiology of P. aeruginosa CF isolates and PAO1 that cannot be detected at the genome level alone. The widening gap between the increasing genomic data and the lack of phenotypic data means that researchers are increasingly reliant on extrapolating from genomic comparisons using experimentally characterized model organisms such as PAO1. While comparative genomics can provide valuable information, our data suggests that such

  15. Characterization of Pseudomonas aeruginosa isolated from chronically infected children with cystic fibrosis in India

    PubMed Central

    Agarwal, Gunjan; Kapil, Arti; Kabra, Susheel Kumar; Das, Bimal Kumar; Dwivedi, Sada Nand

    2005-01-01

    Background Pseudomonas aeruginosa is the leading cause of morbidity and mortality in patients with cystic fibrosis (CF). With chronicity of infection, the organism resides as a biofilm, shows multi-drug resistance, diversifies its colony morphology and becomes auxotrophic. The patients have been found to be colonized with multiple genotypes. The present work was carried out to characterize P. aeruginosa isolated from children with cystic fibrosis using phenotypic and genotypic methods. Results We studied 56 patients with CF attending the Pediatric Chest clinic at All India Institute of Medical Sciences, New Delhi, India during August 1998-August 2001. These patients were regularly followed up at the clinic. Out of 56 patients, 27 were culture positive for P. aeruginosa where 8 were chronically infected (Group1) and 19 were intermittently colonized with the organism (Group2). Patients under Group1 had significantly higher rates of hospitalization, death and colonization with different colony morphotypes (p < 0.05). The isolates from Group1 patients were the positive producers of extended spectrum beta lactamase. A total of 5 auxotrophs were recovered from 2 patients where one was chronically infected with P. aeruginosa and the other was a recently enrolled patient. The auxotrophs had the specific requirement for methionine and arginine. Molecular typing revealed 33 ERIC-PCR (E1-E33) and 5 PCR-ribotyping (P1-P5) patterns. By ERIC-PCR, 4 patients were colonized with 2–4 genotypes and the remaining 23 patients were colonized with the single genotype. Conclusion With chronicity of infection, P. aeruginosa becomes multidrug resistant, diversifies its colony morphology, acquires mucoidity and shows auxotrophy for amino acids. The chronically infected patients can be colonized with multiple genotypes. Thus in a particular clinical set up, high index of suspicion should be there for diagnosis of CF patients so as to prevent the delay in diagnosis and management of CF

  16. Resistance of Pseudomonas aeruginosa Isolates to Hydrogel Contact Lens Disinfection Correlates with Cytotoxic Activity

    PubMed Central

    Lakkis, Carol; Fleiszig, Suzanne M. J.

    2001-01-01

    One of the most common pathogens in infection of hydrogel contact lens wearers is Pseudomonas aeruginosa, which can gain access to the eye via contamination of the lens, lens case, and lens care solutions. Only one strain per species is used in current regulatory testing for the marketing of chemical contact lens disinfectants. The aim of this study was to determine whether P. aeruginosa strains vary in their susceptibility to hydrogel contact lens disinfectants. A method for rapidly screening bacterial susceptibility to contact lens disinfectants was developed, based on measurement of the MIC. The susceptibility of 35 P. aeruginosa isolates to two chemical disinfectants was found to vary among strains. MICs ranged from 6.25 to 100% for both disinfectants at 37°C, and a number of strains were not inhibited by a 100% disinfectant concentration in the lens case environment at room temperature (22°C). Resistance to disinfection appeared to be an inherent rather than acquired trait, since some resistant strains had been isolated prior to the introduction of the disinfectants and some susceptible P. aeruginosa strains could not be made more resistant by repeated disinfectant exposure. A number of P. aeruginosa strains which were comparatively more resistant to short-term disinfectant exposure also demonstrated the ability to grow to levels above the initial inoculum in one chemical disinfectant after long-term (24 to 48 h) disinfectant exposure. Resistance was correlated with acute cytotoxic activity toward corneal epithelial cells and with exsA, which encodes a protein that regulates cytotoxicity via a complex type III secretion system. These results suggest that chemical disinfection solutions may select for contamination with cytotoxic strains. Further investigation of the mechanisms and factors responsible for resistance may also lead to strategies for reducing adverse responses to contact lens wear. PMID:11283074

  17. Evaluation of efflux pumps gene expression in resistant Pseudomonas aeruginosa isolates in an Iranian referral hospital

    PubMed Central

    Pourakbari, Babak; Yaslianifard, Sahar; Yaslianifard, Somaye; Mahmoudi, Shima; Keshavarz-Valian, Sepideh; Mamishi, Setareh

    2016-01-01

    Background and Objectives: Pseudomonas aeruginosa (PA) is one of the most important causes of nosocomial infections and has an intrinsic resistance to many antibiotics. Among all the resistance-nodulation-division (RND) pumps of P. aeruginosa, MexAB-OprM is the first efflux pump found to target multiple classes of antibiotics. This study was aimed to evaluate the expression level of genes expressing MexAB-OprM in clinical isolates of P. aeruginosa. Materials and Methods: In this study, 45 P. aeruginosa strains were isolated from patients admitted to Children’s Medical Center Hospital, an Iranian referral hospital. Disk diffusion and Minimum Inhibitory Concentration (MIC) methods were used for determination of the patterns of resistance to antibiotics. Real-time PCR was used to investigate the expression level of genes of MexAB-OprM efflux pump. Results: Among 45 resistant PA isolates, the frequency of genes overexpression was as follows: MexA (n=25, 55.5%), MexB (n=24, 53.3%) and OprM (n=16, 35.5%). In addition, in 28 strains (62%) overexpression was observed in one of the studied three genes of MexAB-OprM efflux pump. Conclusion: In our study 28 isolates (62%) had increased expression level of efflux pumps genes, MexAB-OprM. Although the efflux pumps play important roles in increasing the resistance towards different antibiotics but the role of other agents and mechanisms in evolution of resistance should not be ignored. Since the concomitant overproduction of other Mex efflux systems might have additive effects on antibiotic resistance, the co-expressing of a multicomponent efflux pump is recommended. On the other hand, the concomitant overproduction of two Mex pumps might have additive effects on resistance to antibiotic. Therefore co-expressing of Mex efflux systems is recommended. PMID:28210464

  18. Host inflammatory responses to first isolation of Pseudomonas aeruginosa from sputum in cystic fibrosis.

    PubMed

    Elborn, J S; Cordon, S M; Shale, D J

    1993-05-01

    Pseudomonas aeruginosa infection of the respiratory tract in patients with cystic fibrosis is a major determinant of morbidity and mortality. However, it has been postulated that the earliest phase of colonization is not associated with injury. To test this hypothesis we determined the association of the first recorded isolation of P. aeruginosa from the sputum on circulating markers of the inflammatory response in 6 patients with cystic fibrosis. At this time circulating C-reactive protein was increased in all 6 and neutrophil elastase alpha 1-antitrypsin complex (elastase-complex) was increased in 5 patients compared with healthy controls. This inflammatory response was associated with a reduction in the FEV1 and FVC of all patients [FEV1, 1.42 +/- 0.87 L (mean +/- SD) at first isolation vs. 2.08 +/- 0.74 L before isolation; P < 0.05; FVC, 1.94 +/- 0.93 L vs. 2.87 +/- 1.01 L, P < 0.05]. At a median interval of 10 months, 5 patients had raised titres of positive IgG antibody to P. aeruginosa, indicating significant exposure to this organism. At this time, lung function had returned to preinfection levels, whilst 3 patients showed continuing features of an inflammatory response, and the group mean value for elastase-complex was raised. Our findings demonstrate that at the time of first isolation of P. aeruginosa from the sputum of patients with cystic fibrosis, there is a concomitant systemic host response and an acute deterioration of pulmonary function.

  19. Complete Genome Sequences of Two Pseudomonas aeruginosa Strains Isolated from Children with Bacteremia.

    PubMed

    Espinosa-Camacho, Luis F; Delgado, Gabriela; Miranda-Novales, Guadalupe; Soberón-Chávez, Gloria; Alcaraz, Luis D; Morales-Espinosa, Rosario

    2017-08-31

    Two Pseudomonas aeruginosa strains isolated from children with bacteremia in Mexico City were sequenced using PacBio RS-II single-molecule real-time (SMRT) technology. The strains consist of a 7.0- to 7.4-Mb chromosome, with a high content of mobile elements, and variation in the genetic content of class 1 integron In1409. Copyright © 2017 Espinosa-Camacho et al.

  20. Mutational and acquired carbapenem resistance mechanisms in multidrug resistant Pseudomonas aeruginosa clinical isolates from Recife, Brazil.

    PubMed

    Cavalcanti, Felipe Lira de Sá; Mirones, Cristina Rodríguez; Paucar, Elena Román; Montes, Laura Álvarez; Leal-Balbino, Tereza Cristina; Morais, Marcia Maria Camargo de; Martínez-Martínez, Luis; Ocampo-Sosa, Alain Antonio

    2015-12-01

    An investigation was carried out into the genetic mechanisms responsible for multidrug resistance in nine carbapenem-resistant Pseudomonas aeruginosa isolates from different hospitals in Recife, Brazil. Susceptibility to antimicrobial agents was determined by broth microdilution. Polymerase chain reaction (PCR) was employed to detect the presence of genes encoding β-lactamases, aminoglycoside-modifying enzymes (AMEs), 16S rRNA methylases, integron-related genes and OprD. Expression of genes coding for efflux pumps and AmpC cephalosporinase were assessed by quantitative PCR. The outer membrane proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The blaSPM-1, blaKPC-2 and blaGES-1 genes were detected in P. aeruginosa isolates in addition to different AME genes. The loss of OprD in nine isolates was mainly due to frameshift mutations, premature stop codons and point mutations. An association of loss of OprD with the overexpression of MexAB-OprM and MexXY-OprM was observed in most isolates. Hyper-production of AmpC was also observed in three isolates. Clonal relationship of the isolates was determined by repetitive element palindromic-PCR and multilocus sequence typing. Our results show that the loss of OprD along with overexpression of efflux pumps and β-lactamase production were responsible for the multidrug resistance in the isolates analysed.

  1. Intraclonal genetic diversity amongst cystic fibrosis and keratitis isolates of Pseudomonas aeruginosa.

    PubMed

    Hall, Amanda J; Fothergill, Joanne L; Kaye, Stephen B; Neal, Timothy J; McNamara, Paul S; Southern, Kevin W; Winstanley, Craig

    2013-02-01

    Given the emergence of transmissible strains of Pseudomonas aeruginosa, such as the Liverpool epidemic strain (LES), in cystic fibrosis (CF) centres, it is important to carry out regular surveillance of isolates. In a survey of 22 P. aeruginosa isolates, each from a different CF patient identified as negative for LES in a paediatric centre in Liverpool, six (23 %) were identified as being the same clone type (clone D) using array-tube genotyping. Using a series of alternative genotyping approaches [PFGE, random amplification of polymorphic DNA (RAPD), variable number of tandem repeats (VNTR) and multilocus sequence typing (MLST)], the six CF clone D isolates and eight previously identified clone D isolates associated with infections leading to keratitis were compared. All but two of the clone D isolates (both keratitis-associated) were assigned by MLST to sequence type 235 and were highly similar using VNTR analysis. However, there was considerable variation found among the isolates when using PFGE or RAPD, highlighting the limitations of these methods. The discordance with respect to two of the isolates identified by array-tube genotyping as clone D, when using all the other typing methods, emphasizes the need to use more than one method for reliable identification of strains.

  2. Isolation of bacteriophages and their application to control Pseudomonas aeruginosa in planktonic and biofilm models.

    PubMed

    Kwiatek, Magdalena; Parasion, Sylwia; Rutyna, Paweł; Mizak, Lidia; Gryko, Romuald; Niemcewicz, Marcin; Olender, Alina; Łobocka, Małgorzata

    2017-04-01

    Pseudomonas aeruginosa is frequently identified as a cause of diverse infections and chronic diseases. It forms biofilms and has natural resistance to several antibiotics. Strains of this pathogen resistant to new-generation beta-lactams have emerged. Due to the difficulties associated with treating chronic P. aeruginosa infections, bacteriophages are amongst the alternative therapeutic options being actively researched. Two obligatorily lytic P. aeruginosa phages, vB_PaeM_MAG1 (MAG1) and vB_PaeP_MAG4 (MAG4), have been isolated and characterized. These phages belong to the PAK_P1likevirus genus of the Myoviridae family and the LIT1virus genus of the Podoviridae family, respectively. They adsorb quickly to their hosts (∼90% in 5 min), have a short latent period (15 min), and are stable during storage. Each individual phage propagated in approximately 50% of P. aeruginosa strains tested, which increased to 72.9% when phages were combined into a cocktail. While MAG4 reduced biofilm more effectively after a short time of treatment, MAG1 was more effective after a longer time and selected less for phage-resistant clones. A MAG1-encoded homolog of YefM antitoxin of the bacterial toxin-antitoxin system may contribute to the superiority of MAG1 over MAG4. Copyright © 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  3. Genetic Analysis of Pseudomonas aeruginosa Isolates from the Sputa of Australian Adult Cystic Fibrosis Patients

    PubMed Central

    Anthony, Mario; Rose, Barbara; Pegler, Mary Beard; Elkins, Mark; Service, Helen; Thamotharampillai, Keerthi; Watson, Jason; Robinson, Michael; Bye, Peter; Merlino, John; Harbour, Colin

    2002-01-01

    Genetic investigations were carried out with 50 phenotypically selected strains of Pseudomonas aeruginosa from 18 patients attending an Australian cystic fibrosis (CF) center. The isolates were analyzed by restriction fragment length polymorphism (RFLP) analysis by pulsed-field gel electrophoresis (PFGE). Phylogenetic analysis of the macrorestriction patterns showed rates of genetic similarity ranging from 76 to 100%; 24 (48%) of the strains from 11 patients had greater than 90% similarity. A dominant strain emerged: 15 isolates from seven patients had identical PFGE patterns, and 4 other isolates were very closely related. The 50 isolates were grouped into 21 pulsotypes on the basis of visual delineation of a three-band difference. Ten of the 18 (56%) patients were infected with clonal or subclonal strains. Sequence analysis of PCR products derived from the mucA gene showed 20 mutations, with the number of mutations in individual isolates ranging from 1 to 4; 19 of these changes are reported here for the first time. Potentially functional changes were found in 22 (44%) isolates. Eight changes (five transversions and three single base deletions) led to premature stop codons, providing support for the presence of mucA mutations as one pathway to mucoidy. There was a trend toward an association between the dominant strain and lack of potentially functional mucA mutations (P = 0.09 by the χ2 test) but no relationship between genotype and phenotype. This is the first study of genetic variation in P. aeruginosa isolates from adult Australian CF patients. The findings highlight the need for further investigations on the transmissibility of P. aeruginosa in CF patients. PMID:12149328

  4. Efflux pump regulatory genes mutations in multidrug resistance Pseudomonas aeruginosa isolated from wound infections in Isfahan hospitals

    PubMed Central

    Vaez, Hamid; Faghri, Jamshid; Isfahani, Bahram Nasr; Moghim, Sharareh; Yadegari, Sima; Fazeli, Hossein; Moghofeei, Mohsen; Safaei, Hajieh Ghasemian

    2014-01-01

    Background: Multidrug resistance Pseudomonas aeruginosa (MDR-P. aeruginosa) is a worldwide threat for public health. Hyperexpression of efflux pump systems (MexAB-OprM and MexCD-OprJ), which is a well-known mechanisms for MDR emerging, is controlled by regulatory genes, mexR and nfxB, respectively. The aim of this study was to evaluate point mutations in mexR and nfxB genes in MDR- P. aeruginosa isolated from wound infections. Materials and Methods: A total of 34 P. aeruginosa cultures obtained from wound infections were analyzed. Among them eight isolates identified as MDR-P. aeruginosa and were subjected to determination of mutations in mexR and nfxB genes. Results: We detected eight-point mutations in mexR and 12-point mutations in nfxB. The most common mutations were common G327-A (eight isolates), G384-A (eight isolates), G411-A (eight isolates). Mutations in A371-C and A372-C were the predominant substitution which was seen in nfxB. Amino acid substitutions were also found at position 124 and 126 for NfxB and MexR, respectively. Conclusions: P. aeruginosa isolates with mutation in efflux pump regulatory genes such as mexR and nfxB could be a main factor contributed to antibiotic resistance and must be considered in antibiotic treatment. PMID:24949288

  5. Efflux pump regulatory genes mutations in multidrug resistance Pseudomonas aeruginosa isolated from wound infections in Isfahan hospitals.

    PubMed

    Vaez, Hamid; Faghri, Jamshid; Isfahani, Bahram Nasr; Moghim, Sharareh; Yadegari, Sima; Fazeli, Hossein; Moghofeei, Mohsen; Safaei, Hajieh Ghasemian

    2014-01-01

    Multidrug resistance Pseudomonas aeruginosa (MDR-P. aeruginosa) is a worldwide threat for public health. Hyperexpression of efflux pump systems (MexAB-OprM and MexCD-OprJ), which is a well-known mechanisms for MDR emerging, is controlled by regulatory genes, mexR and nfxB, respectively. The aim of this study was to evaluate point mutations in mexR and nfxB genes in MDR- P. aeruginosa isolated from wound infections. A total of 34 P. aeruginosa cultures obtained from wound infections were analyzed. Among them eight isolates identified as MDR-P. aeruginosa and were subjected to determination of mutations in mexR and nfxB genes. We detected eight-point mutations in mexR and 12-point mutations in nfxB. The most common mutations were common G327-A (eight isolates), G384-A (eight isolates), G411-A (eight isolates). Mutations in A371-C and A372-C were the predominant substitution which was seen in nfxB. Amino acid substitutions were also found at position 124 and 126 for NfxB and MexR, respectively. P. aeruginosa isolates with mutation in efflux pump regulatory genes such as mexR and nfxB could be a main factor contributed to antibiotic resistance and must be considered in antibiotic treatment.

  6. Multilocus sequence typing analysis of Pseudomonas aeruginosa isolated from pet Chinese stripe-necked turtles (Ocadia sinensis)

    PubMed Central

    Wendt, Mitchell

    2016-01-01

    Our research sought to characterize the phylogeny of Pseudomonas aeruginosa isolated from pet Chinese stripe-necked turtles (Ocadia sinensis) to better understand its evolutionary relation to other isolates and increase understanding of a potential zoonotic pathogen transmitted through direct contact with pet turtles. Thirty-one Pseudomonas aeruginosa isolates were obtained from both immature and adult turtles sold in pet shops in Korea. To characterize the phylogenic position of Chinese stripe-necked turtle-borne P. aeruginosa relative to other strains, multilocus sequence typing (MLST) analysis was performed due to the accessibility and breadth of MLST databases. Seven housekeeping genes (acsA, aroE, guaA, mutL, nuoD, ppsA, and trpE) were sequenced and the results were compared with data from the MLST database. The genes were further used for phylogenetic analysis of P. aeruginosa using concatenated gene fragments. Both rooted and unrooted phylogenetic trees were generated. Eleven distinct sequence types were present within the isolates among which seven were new. Expanding an unrooted phylogenetic tree to include P. aeruginosa MLST sequences isolated from various other geographic locations and sources revealed a divergent cluster containing the majority of isolates obtained from turtles. This suggests that P. aeruginosa strains particularly well-adapted for inhabiting turtles occupy a distinct phylogenetic position. PMID:28053614

  7. Comparison of the exoS Gene and Protein Expression in Soil and Clinical Isolates of Pseudomonas aeruginosa

    PubMed Central

    Ferguson, Michael W.; Maxwell, Jill A.; Vincent, Timothy S.; da Silva, Jack; Olson, Joan C.

    2001-01-01

    Exoenzyme S (ExoS) is translocated into eukaryotic cells by the type III secretory process and has been hypothesized to function in conjunction with other virulence factors in the pathogenesis of Pseudomonas aeruginosa. To gain further understanding of how ExoS might contribute to P. aeruginosa survival and virulence, ExoS expression and the structural gene sequence were determined in P. aeruginosa soil isolates and compared with ExoS of clinical isolates. Significantly higher levels of ExoS ADP-ribosyltransferase (ADPRT) activity were detected in culture supernatants of soil isolates compared to those of clinical isolates. The higher levels of ADPRT activity of soil isolates reflected both the increased production of ExoS and the production of ExoS having a higher specific activity. ExoS structural gene sequence comparisons found the gene to be highly conserved among soil and clinical isolates, with the greatest number of nonsynonymous substitutions occurring within the region of ExoS encoding GAP function. The lack of amino acid changes in the ADPRT region in association with a higher specific activity implies that other factors produced by P. aeruginosa or residues outside the ADPRT region are affecting ExoS ADPRT activity. The data are consistent with ExoS being integral to P. aeruginosa survival in the soil and suggest that, in the transition of P. aeruginosa from the soil to certain clinical settings, the loss of ExoS expression is favored. PMID:11254575

  8. Identification of outer membrane Porin D as a vitronectin-binding factor in cystic fibrosis clinical isolates of Pseudomonas aeruginosa.

    PubMed

    Paulsson, Magnus; Singh, Birendra; Al-Jubair, Tamim; Su, Yu-Ching; Høiby, Niels; Riesbeck, Kristian

    2015-09-01

    Pseudomonas aeruginosa is a pathogen that frequently colonizes patients with cystic fibrosis (CF) or chronic obstructive pulmonary disease (COPD). Several pathogens are known to bind vitronectin to increase their virulence. Vitronectin has been shown to enhance P. aeruginosa adhesion to host epithelial cells. We screened clinical isolates from the airways of CF patients and from the bloodstream of patients with bacteremia for binding of vitronectin. Two-dimensional SDS-PAGE and a proteomic approach were used to identify vitronectin-receptors in P. aeruginosa. P. aeruginosa from the airways of CF patients (n=27) bound more vitronectin than bacteremic isolates (n=15, p=0.025). Porin D (OprD) was identified as a vitronectin-binding protein. A P. aeruginosa oprD transposon insertion mutant had a decreased binding to soluble and immobilized vitronectin (p≤0.001). P. aeruginosa isolates obtained from CF patients significantly bound vitronectin. Porin D was defined as a novel P. aeruginosa vitronectin-receptor, and we postulate that the Porin D-dependent interaction with vitronectin may be important for colonization. Copyright © 2015 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

  9. Virulence Gene Profiles of Multidrug-Resistant Pseudomonas aeruginosa Isolated From Iranian Hospital Infections

    PubMed Central

    Fazeli, Nastaran; Momtaz, Hassan

    2014-01-01

    Background: The most common hospital-acquired pathogen is Pseudomonas aeruginosa. It is a multidrug resistant bacterium causing systemic infections. Objectives: The present study was carried out in order to investigate the distribution of virulence factors and antibiotic resistance properties of Pseudomonas aeruginosa isolated from various types of hospital infections in Iran. Patients and Methods: Two-hundred and seventeen human infection specimens were collected from Baqiyatallah and Payambaran hospitals in Tehran, Iran. The clinical samples were cultured immediately and samples positive for P. aeruginosa were analyzed for the presence of antibiotic resistance and bacterial virulence genes using PCR (polymerase chain reaction). Antimicrobial susceptibility testing was performed using disk diffusion methodology with Müeller–Hinton agar. Results: Fifty-eight out of 127 (45.66%) male infection specimens and 44 out of 90 (48.88%) female infection specimens harbored P. aeruginosa. Also, 65% (in male specimens) and 21% (in female specimens) of respiratory system infections were positive for P. aeruginosa, which was a high rate. The genes encoding exoenzyme S (67.64%) and phospholipases C (45.09%) were the most common virulence genes found among the strains. The incidences of various β-lactams encoding genes, including blaTEM, blaSHV, blaOXA, blaCTX-M, blaDHA, and blaVEB were 94.11%, 16.66%, 15.68%, 18.62%, 21.56%, and 17.64%, respectively. The most commonly detected fluoroquinolones encoding gene was gyrA (15. 68%). High resistance levels to penicillin (100%), tetracycline (90.19%), streptomycin (64.70%), and erythromycin (43.13%) were observed too. Conclusions: Our findings should raise awareness about antibiotic resistance in hospitalized patients in Iran. Clinicians should exercise caution in prescribing antibiotics, especially in cases of human infections. PMID:25763199

  10. Drug resistance profile and biofilm forming potential of Pseudomonas aeruginosa isolated from contact lenses in Karachi-Pakistan

    PubMed Central

    2013-01-01

    Background The contaminated contact lens provides Pseudomonas aeruginosa an ideal site for attachment and biofilm production. Continuous contact of the eye to the biofilm-infested lens can lead to serious ocular diseases, such as keratitis (corneal ulcers). The biofilms also prevent effective penetration of the antibiotics, which increase the chances of antibiotic resistance. Methods For this study, 22 Pseudomonas aeruginosa isolates were obtained from 36 contact lenses and 14 contact lens protective fluid samples. These isolates were tested against eight commonly used antibiotics using Kirby-Bauer disk diffusion method. The biofilm forming potential of these isolates was also evaluated using various qualitative and quantitative techniques. Finally, a relationship between biofilm formation and antibiotic resistance was also examined. Results The isolates of Pseudomonas aeruginosa tested were found resistant to most of the antibiotics tested. Qualitative and quantitative biofilm analysis revealed that most of the isolates exhibited strong biofilm production. The biofilm production was significantly higher in isolates that were multi-drug resistant (p < 0.0001). Conclusion Our study indicates that multi-drug resistant, biofilm forming Pseudomonas aeruginosa isolates are mainly involved in contact lens associated infections. This appears to be the first report from Pakistan, which analyzes both antibiotic resistance profile and biofilm forming potential of Pseudomonas aeruginosa isolates from contact lens of the patients with contact lens associated infections. PMID:24134792

  11. Biofilm Formation and β-Lactamase Production in Burn Isolates of Pseudomonas aeruginosa

    PubMed Central

    Heydari, Samira; Eftekhar, Fereshteh

    2015-01-01

    Background: Pseudomonas aeruginosa is an important nosocomial pathogen characterized by its innate resistance to multiple antimicrobial agents. Plasmid-mediated drug resistance also occurs by the production of extended-spectrum β-lactamases (ESBL), metallo β-lactamases (MBL), and AmpC β-lactamases. Another important factor for establishment of chronic infections by P. aeruginosa is biofilm formation mediated by the psl gene cluster. Objectives: The aim of this study was to evaluate biofilm formation and presence of the pslA gene in burn isolates of P. aeruginosa as well as the association of antibiotic resistance, MBL, ESBL and AmpC β-lactamase production with biofilm formation among the isolates. Materials and Methods: Sixty-two burn isolates of P. aeruginosa were obtained from Shahid Motahari Hospital in Tehran from August to October 2011. Antibiotic susceptibility was determined by the disc diffusion assay. MBL, AmpC and ESBL production were screened using the double disc synergy test, AmpC disc test and combined disc diffusion assay, respectively. The potential to form biofilm was measured using the microtiter plate assay and pslA gene was detected using specific primers and PCR. Results: Biofilm formation was observed in 43.5% of the isolates, of which 66.7% produced strong and 33.3% formed weak biofilms. All biofilm-positive and 14.2% of biofilm-negative isolates harbored the pslA gene. MBL, AmpC and ESBL production were significantly higher in the biofilm-positive isolates (70.3%, 62.9% and 33.3%, respectively) compared to the biofilm-negative strains (31.4%, 34.2% and 20%, respectively). Overall, 19 isolates (30.6%) co-produced MBL and AmpC, among which the majority were biofilm-positive (63.1%). Finally, four isolates (6.4%) had all three enzymes, of which 3 (75%) produced biofilm. Conclusions: Biofilm formation (both strong and weak) strongly correlated with pslA gene carriage. Biofilm formation also correlated with MBL and AmpC

  12. Fluoroquinolone resistance of Pseudomonas aeruginosa isolates causing nosocomial infection is correlated with levofloxacin but not ciprofloxacin use.

    PubMed

    Lee, Yuarn-Jang; Liu, Hsin-Yi; Lin, Yi-Chun; Sun, Kuo-Lun; Chun, Chi-Li; Hsueh, Po-Ren

    2010-03-01

    This study investigated the correlation between fluoroquinolone (ciprofloxacin or levofloxacin) use and rates of fluoroquinolone resistance in Pseudomonas aeruginosa isolates from patients with nosocomial infection at a medical centre in Taiwan. Antibiotic utilisation data were extracted on a monthly basis from the inpatient pharmacy computer system records from January 2003 to December 2008. Fluoroquinolone use was expressed as defined daily dose per 1000 patient-days and was correlated with rates of fluoroquinolone-resistant P. aeruginosa every 6 months. Regression analysis was performed to explore the relationship between ciprofloxacin and levofloxacin use (both parenteral and oral forms) and resistance of P. aeruginosa isolates. During the study period, the susceptibility of P. aeruginosa to fluoroquinolones decreased after increasing use of fluoroquinolones, and increased after decreasing use of levofloxacin. Parenteral levofloxacin use was significantly positively correlated with resistance of P. aeruginosa to ciprofloxacin (P=0.015) and fluoroquinolones (either ciprofloxacin or levofloxacin, P=0.014). Use of both parenteral and oral forms of levofloxacin was also significantly positively correlated with resistance of P. aeruginosa isolates to ciprofloxacin (P=0.029), levofloxacin (P=0.031) and fluoroquinolones (P=0.010). The total amount of ciprofloxacin (oral and parenteral) and parenteral ciprofloxacin use were negatively correlated with resistance of P. aeruginosa isolates to fluoroquinolones. However, the amounts of oral ciprofloxacin, parenteral levofloxacin, oral levofloxacin and total levofloxacin use were each positively correlated with resistance of P. aeruginosa to fluoroquinolones. Levofloxacin use was associated with increased resistance of P. aeruginosa to fluoroquinolones, whereas ciprofloxacin use did not have a significant impact on fluoroquinolone resistance rates. Copyright 2009 Elsevier B.V. and the International Society of Chemotherapy

  13. Population structure and antimicrobial susceptibility of both nonpersistent and persistent Pseudomonas aeruginosa isolates recovered from cystic fibrosis patients.

    PubMed

    Fernández-Olmos, Ana; García-Castillo, María; Alba, José María; Morosini, María Isabel; Lamas, Adelaida; Romero, Beatriz; Galán, Juan Carlos; del Campo, Rosa; Cantón, Rafael

    2013-08-01

    Seventy-six Pseudomonas aeruginosa isolates recovered from chronically (n=18) and nonchronically (n=18) colonized cystic fibrosis (CF) patients (2002 to 2009) were grouped in separate polyclonal populations. International CF epidemic clones were not identified, but the high-risk clone ST274, also found circulating in Spanish hospitals, was present. Persistent isolates were more resistant to antibiotics than nonpersistent isolates.

  14. Population Structure and Antimicrobial Susceptibility of Both Nonpersistent and Persistent Pseudomonas aeruginosa Isolates Recovered from Cystic Fibrosis Patients

    PubMed Central

    Fernández-Olmos, Ana; García-Castillo, María; Alba, José María; Morosini, María Isabel; Lamas, Adelaida; Romero, Beatriz; Galán, Juan Carlos; del Campo, Rosa

    2013-01-01

    Seventy-six Pseudomonas aeruginosa isolates recovered from chronically (n = 18) and nonchronically (n = 18) colonized cystic fibrosis (CF) patients (2002 to 2009) were grouped in separate polyclonal populations. International CF epidemic clones were not identified, but the high-risk clone ST274, also found circulating in Spanish hospitals, was present. Persistent isolates were more resistant to antibiotics than nonpersistent isolates. PMID:23761158

  15. First Report of OXA-4, an ESBL Isolated from Pseudomonas aeruginosa a South Indian Strain.

    PubMed

    Kingsley, S A Jemima; Verghese, Susan

    2013-09-01

    The OXA-type β-lactamases are so named because of their oxacillin-hydrolyzing abilities. In this study we characterize an extended spectrum β-lactamase, designated OXA-4, produced by a clinical isolate of Pseudomonas aeruginosa. ESBL production was detected by double disk synergy test. The P. aeruginosa isolate was obtained from endotracheal suction tip of 84 years old male patient diagnosed with CVA and hypertension. ESBL producing OXA β-lactamases was detected by PCR with primers specific to the conserved regions of the coding genes. Iso electric focusing was done to confirm the significance, sequencing the amplified product was also done. In the phenotypic identification, the strain was highly resistant to third generation cephalosporins and also to imipenem. The PCR amplified product for OXA β-lactamase was viewed at 919 bp. The pI point for the same was identified at 7.2. With the help of sequencing the amplified OXA β-lactamase was identified as OXA-4 gene. Here we report P. aeruginosa producing OXA-4 ESBL for the first time in the Indian subcontinent.

  16. Phylogenetic study of metallo-β-lactamase producing multidrug resistant Pseudomonas aeruginosa isolates from burn patients.

    PubMed

    Jena, Jayanti; Debata, Nagen Kumar; Sahoo, Rajesh Kumar; Subudhi, Enketeswara

    2015-12-01

    The present study was carried out to understand the clonal relationship using enterobacteriaceae repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) among metallo-β-lactamase (MBL) producing multidrug resistant Pseudomonas aeruginosa isolates from burn victims and their susceptibility to commonly used anti-pseudomonal agents. In the present study 94 non-duplicate P. aeruginosa strains from the wound samples of burn patients were included. Identification of the isolates was done by biochemical methods and antibiotic sensitivity was done by disc diffusion method following CLSI (Clinical Laboratory Standard Institute) guidelines. By using imipenem (IPM)-EDTA disk diffusion/double disc synergy method carbapenem resistant organisms were tested for MBL. To define the clonal relationship ERIC-PCR was used. Of the 94 isolates, 18 (19.14%) were found resistant to IPM and MBL production was shown 11 (11.70%) by the IPM-EDTA disc diffusion method. From dendrogram of the ERIC-PCR profile four major clusters were obtained (A, B, C and D). Cluster B contained the majority of the isolates (6 strains 1, 4, 8, 9, 10 and 11). This study using ERIC-PCR of randomly collected isolates exhibits high genetic diversity which rules out cross contamination frequency. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

  17. Optimisation of AP-PCR fingerprinting discriminatory power for clinical isolates of Pseudomonas aeruginosa.

    PubMed

    Dabrowski, Waldemar; Czekajlo-Kolodziej, Urszula; Medrala, Dagmara; Giedrys-Kalemba, Stefania

    2003-01-21

    Recently methods based on analysis of arbitrarily amplified target sites of microorganism genomes have been extensively applied in microbiological studies. The range of their applications is limited by problems with discrimination and reproducibility resulting from lack of standardised and reliable methods of optimisation. By orthogonal-array optimisation most advantageous and optimal parameters for highly discriminatory primers (CagA2+CMVin2) were selected and efficient AP-PCR (arbitrarily primed-polymerase chain reaction) fingerprinting conditions for Pseudomonas aeruginosa isolates were set up. Stable and multiplex amplicon profiles obtained in this study revealed high level of intraspecies DNA polymorphism among 20 analysed clinical strains of P. aeruginosa proving optimised AP-PCR fingerprinting to be useful in epidemiological typing of the species.

  18. Aloe vera Gel: Effective Therapeutic Agent against Multidrug-Resistant Pseudomonas aeruginosa Isolates Recovered from Burn Wound Infections

    PubMed Central

    Fazeli, Maryam; Azad, Mehdi; Seyedjavadi, Sima Sadat; Mousavi, Reza

    2015-01-01

    Objective. Aloe vera is an herbal medicinal plant with biological activities, such as antimicrobial, anticancer, anti-inflammatory, and antidiabetic ones, and immunomodulatory properties. The purpose of this study was investigation of in vitro antimicrobial activity of A. vera gel against multidrug-resistant (MDR) Pseudomonas aeruginosa isolated from patients with burn wound infections. Methods. During a 6-month study, 140 clinical isolates of P. aeruginosa were collected from patients admitted to the burn wards of a hospital in Tehran, Iran. Antimicrobial susceptibility test was carried out against the pathogens using the A. vera gel and antibiotics (imipenem, gentamicin, and ciprofloxacin). Results. The antibiogram revealed that 47 (33.6%) of all isolates were MDR P. aeruginosa. The extract isolated from A. vera has antibacterial activity against all of isolates. Also, 42 (89.4%) isolates were inhibited by A. vera gel extract at minimum inhibitory concentration (MIC) ≤ 200 µg/mL. MIC value of A. vera gel for other isolates (10.6%) was 800 µg/mL. All of MDR P. aeruginosa strains were inhibited by A. vera at similar MIC50 and MIC90 200 µg/mL. Conclusion. Based on our results, A. vera gel at various concentrations can be used as an effective antibacterial agent in order to prevent wound infection caused by P. aeruginosa. PMID:26266047

  19. Aloe vera Gel: Effective Therapeutic Agent against Multidrug-Resistant Pseudomonas aeruginosa Isolates Recovered from Burn Wound Infections.

    PubMed

    Goudarzi, Mehdi; Fazeli, Maryam; Azad, Mehdi; Seyedjavadi, Sima Sadat; Mousavi, Reza

    2015-01-01

    Objective. Aloe vera is an herbal medicinal plant with biological activities, such as antimicrobial, anticancer, anti-inflammatory, and antidiabetic ones, and immunomodulatory properties. The purpose of this study was investigation of in vitro antimicrobial activity of A. vera gel against multidrug-resistant (MDR) Pseudomonas aeruginosa isolated from patients with burn wound infections. Methods. During a 6-month study, 140 clinical isolates of P. aeruginosa were collected from patients admitted to the burn wards of a hospital in Tehran, Iran. Antimicrobial susceptibility test was carried out against the pathogens using the A. vera gel and antibiotics (imipenem, gentamicin, and ciprofloxacin). Results. The antibiogram revealed that 47 (33.6%) of all isolates were MDR P. aeruginosa. The extract isolated from A. vera has antibacterial activity against all of isolates. Also, 42 (89.4%) isolates were inhibited by A. vera gel extract at minimum inhibitory concentration (MIC) ≤ 200 µg/mL. MIC value of A. vera gel for other isolates (10.6%) was 800 µg/mL. All of MDR P. aeruginosa strains were inhibited by A. vera at similar MIC50 and MIC90 200 µg/mL. Conclusion. Based on our results, A. vera gel at various concentrations can be used as an effective antibacterial agent in order to prevent wound infection caused by P. aeruginosa.

  20. ISOLATION AND PRELIMINARY CHARACTERISTICS OF THREE BACTERIOPHAGES ASSOCIATED WITH A LYSOGENIC STRAIN OF PSEUDOMONAS AERUGINOSA, 12

    PubMed Central

    Feary, Thomas W.; Fisher, Earl; Fisher, Thelma N.

    1964-01-01

    Feary, Thomas W. (Tulane University School of Medicine, New Orleans, La.), Earl Fisher, Jr., and Thelma N. Fisher. Isolation and preliminary characteristics of three bacteriophages associated with a lysogenic strain of Pseudomonas aeruginosa. J. Bacteriol. 87:196–208. 1964.—Three bacteriophages designated 7v, 7m, and 7s were isolated from a lysogenic strain of Pseudomonas aeruginosa designated Ps-7. The three viruses were found to be completely unrelated on the basis of plaque morphology, host range, serology, ultraviolet induction, sensitivity to heat, and particle morphology as revealed by electron microscopy. In addition, it was shown that the three phages were incapable of plaque formation on bacteria other than various strains of P. aeruginosa. Of the three phages, only phage 7v was capable of plaque formation on strain Ps-7. The growth of phage 7v on strain Ps-7 exhibited properties which suggest that this virus arises as the result of mutation in a temperate phage for which strain Ps-7 is lysogenic. Phages 7m and 7s are incapable of plaque formation on strain Ps-7, but are adsorbed at characteristic rates to cell suspensions of strain Ps-7. The relationship between phage 7m and strain Ps-7 was shown to meet the classical criteria for lysogeny. Because phage 7s contains ribonucleic acid as its nucleic acid component, it was concluded that its production by strain Ps-7 and the demonstration of immunity of strain Ps-7 to infection by phage 7s were not sufficient evidence to define the nature of the relationship between phage 7s and P. aeruginosa strain Ps-7. It was observed that under certain conditions the infectious titer of phage 7s preparations are markedly reduced in the presence of ribonuclease. Images PMID:14102854

  1. Antimicrobial Susceptibility of Pseudomonas aeruginosa Isolated from Cystic Fibrosis Patients in Northern Europe.

    PubMed

    Mustafa, Muhammad-Hariri; Chalhoub, Hussein; Denis, Olivier; Deplano, Ariane; Vergison, Anne; Rodriguez-Villalobos, Hector; Tunney, Michael M; Elborn, J Stuart; Kahl, Barbara C; Traore, Hamidou; Vanderbist, Francis; Tulkens, Paul M; Van Bambeke, Françoise

    2016-11-01

    Pseudomonas aeruginosa is a major cause of morbidity and mortality in cystic fibrosis patients. This study compared the antimicrobial susceptibilities of 153 P. aeruginosa isolates from the United Kingdom (UK) (n = 58), Belgium (n = 44), and Germany (n = 51) collected from 118 patients during routine visits over the period from 2006 to 2012. MICs were measured by broth microdilution. Genes encoding extended-spectrum β-lactamases (ESBL), metallo-β-lactamases, and carbapenemases were detected by PCR. Pulsed-field gel electrophoresis and multilocus sequence typing were performed on isolates resistant to ≥3 antibiotic classes among the penicillins/cephalosporins, carbapenems, fluoroquinolones, aminoglycosides, and polymyxins. Based on EUCAST/CLSI breakpoints, susceptibility rates were ≤30%/≤40% (penicillins, ceftazidime, amikacin, and ciprofloxacin), 44 to 48%/48 to 63% (carbapenems), 72%/72% (tobramycin), and 92%/78% (colistin) independent of patient age. Sixty percent of strains were multidrug resistant (MDR; European Centre for Disease Prevention and Control criteria). Genes encoding the most prevalent ESBL (BEL, PER, GES, VEB, CTX-M, TEM, SHV, and OXA), metallo-β-lactamases (VIM, IMP, and NDM), or carbapenemases (OXA-48 and KPC) were not detected. The Liverpool epidemic strain (LES) was prevalent in UK isolates only (75% of MDR isolates). Four MDR sequence type 958 (ST958) isolates were found to be spread over the three countries. The other MDR clones were evidenced in ≤3 isolates and localized in a single country. A new sequence type (ST2254) was discovered in one MDR isolate in Germany. Clonal and nonclonal isolates with different susceptibility profiles were found in 20 patients. Thus, resistance and MDR are highly prevalent in routine isolates from 3 countries, with meropenem, tobramycin, and colistin remaining the most active drugs. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  2. In vitro activity of ceftolozane/tazobactam against clinical isolates of Pseudomonas aeruginosa in the planktonic and biofilm states.

    PubMed

    Velez Perez, Antonio L; Schmidt-Malan, Suzannah M; Kohner, Peggy C; Karau, Melissa J; Greenwood-Quaintance, Kerryl E; Patel, Robin

    2016-07-01

    Pseudomonas aeruginosa causes a variety of life-threatening infections, some of which are associated with planktonic and others with biofilm states. Herein, we tested the combination of the novel cephalosporin, ceftolozane, with the β-lactamase inhibitor, tazobactam, against planktonic and biofilm forms of 54 clinical isolates of P. aeruginosa, using cefepime as a comparator. MIC values were determined following Clinical and Laboratory Standards Institute (CLSI) guidelines. Minimum biofilm inhibitory concentration (MBIC) values were determined using biofilm-laden pegged lids incubated in antimicrobial challenge plates containing varying concentrations of ceftolozane/tazobactam. Pegged lids were then incubated in growth recovery plates containing cation-adjusted Mueller-Hinton broth to determine the minimum biofilm bactericidal concentration (MBBC). Ceftolozane/tazobactam was highly active against planktonic P. aeruginosa, with all 54 isolates studied testing susceptible (MIC ≤4/4μg/mL). On the other hand, 51/54 biofilm P. aeruginosa had MBICs ≥16/4μg/mL, and all 54 isolates had MBBCs >32μg/mL. Of the 54 isolates, 45 (83.3%) tested susceptible to cefepime, with the MIC50/MIC90 being 4/16μg/mL, respectively, and the MBIC90 and MBBC90 both being >256μg/mL. Although ceftolozane/tazobactam is a promising antimicrobial agent for the treatment of P. aeruginosa infections, it is not highly active against P. aeruginosa biofilms. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Optimization of environmental factors for improved production of rhamnolipid biosurfactant by Pseudomonas aeruginosa RS29 on glycerol.

    PubMed

    Saikia, Rashmi Rekha; Deka, Suresh; Deka, Manab; Sarma, Hemen

    2012-08-01

    A biosurfactant producing Pseudomonas aeruginosa RS29 (identified on the basis of 16S rDNA analysis) with good foaming and emulsification properties has been isolated from crude oil contaminated sites. Optimization of different environmental factors was carried out with an objective to achieve maximum production of biosurfactant. Production of biosurfactant was estimated in terms of surface tension reduction and emulsification (E24) index. It was recorded that the isolated strain produced highest biosurfactant after 48 h of incubation at 37.5 °C, with a pH range of 7-8 and at salinity <0.8% (w/v). Ammonium nitrate used in the experiment was the best nitrogen source for the growth of biomass of P. aeruginosa RS29. On the other hand sodium and potassium nitrate enhanced the production of biosurfactant (Surface tension, 26.3 and 26.4 mN/m and E24 index, 80 and 79% respectively). The CMC of the biosurfactant was 90 mg/l. Maximum biomass (6.30 g/l) and biosurfactant production (0.80 g/l) were recorded at an optimal C/N ratio of 12.5. Biochemical analysis and FTIR spectra confirmed that the biosurfactant was rhamnolipid in nature. GC-MS analysis revealed the presence of C(8) and C(10) fatty acid components in the purified biosurfactant.

  4. Genotyping of Pseudomonas aeruginosa strains isolated from burn patients by RAPD-PCR.

    PubMed

    Nanvazadeh, Fatemeh; Khosravi, Azar Dokht; Zolfaghari, Mohammad Reza; Parhizgari, Najmeh

    2013-11-01

    Pseudomonas aeruginosa is one of the important causes of nosocomial infections that easily gains resistance to many antibiotics. This opportunistic pathogen is a major health hazard particularly in immunodeficient patients, patients in intensive care units (ICU) and burn units with life threatening outcome. The bacterium may be originated from different or common sources, and comprises a high colonization and transmission capacity. The aim of present study was to investigate the genotypic variation of Pseudomonas aeroginosa strains isolated from burn patients by using Random Amplified Polymorphic DNA (RAPD) method. Totally 70 clinical samples were collected from burn patients in Taleghani Burn Hospital of Ahvaz. Fifty out of total samples were positive for P. aeruginosa by application of conventional culture and biochemical identification tests. DNA was extracted from the isolates and the RAPD-PCR method was applied to the DNA extracts according to standard method using a short single primer of 272. The technique created repetitive electrophoresis patterns which was used for genotypic differentiation. RAPD-PCR, created 9 genotypic profiles designated as I-IX with base pair length ranging from 180 to 2700. Each genotype showed between 3 and 6 different weight DNA bands. Genotype I was the most prevalent, identified in 10 bacterial isolates (20%). Genotypes I, II and VI were mostly common in patients with more severe burn, and were mainly isolated from wound and blood samples obtained from the same patients. In present study, we found RAPD-PCR technique as a useful tool for investigation of the genetic variation among P. aeruginosa strains. This is a rapid, low cost, genotypic method with high discriminatory power. The results could assist to screen for the original of infection caused by this organism with subsequent control of colonization and transmission. Copyright © 2013 Elsevier Ltd and ISBI. All rights reserved.

  5. Is genotyping of single isolates sufficient for population structure analysis of Pseudomonas aeruginosa in cystic fibrosis airways?

    PubMed

    Sommer, Lea M; Marvig, Rasmus L; Luján, Adela; Koza, Anna; Pressler, Tacjana; Molin, Søren; Johansen, Helle K

    2016-08-09

    The primary cause of morbidity and mortality in cystic fibrosis (CF) patients is lung infection by Pseudomonas aeruginosa. Therefore much work has been done to understand the adaptation and evolution of P. aeruginosa in the CF lung. However, many of these studies have focused on longitudinally collected single isolates, and only few have included cross-sectional analyses of entire P. aeruginosa populations in sputum samples. To date only few studies have used the approach of metagenomic analysis for the purpose of investigating P. aeruginosa populations in CF airways. We analysed five metagenomes together with longitudinally collected single isolates from four recently chronically infected CF patients. With this approach we were able to link the clone type and the majority of SNP profiles of the single isolates to that of the metagenome(s) for each individual patient. Based on our analysis we find that when having access to comprehensive collections of longitudinal single isolates it is possible to rediscover the genotypes of the single isolates in the metagenomic samples. This suggests that information gained from genome sequencing of comprehensive collections of single isolates is satisfactory for many investigations of adaptation and evolution of P. aeruginosa to the CF airways.

  6. Inhibition of quorum-sensing-dependent virulence factors and biofilm formation of clinical and environmental Pseudomonas aeruginosa strains by ZnO nanoparticles.

    PubMed

    García-Lara, B; Saucedo-Mora, M Á; Roldán-Sánchez, J A; Pérez-Eretza, B; Ramasamy, M; Lee, J; Coria-Jimenez, R; Tapia, M; Varela-Guerrero, V; García-Contreras, R

    2015-09-01

    Quorum quenching decreases Pseudomonas aeruginosa virulence factors and biofilm formation, alleviating infections in animal models. Nevertheless, it is usually performed in laboratory strains such as PAO1 and PA14, and studies involving clinical or environmental isolates are scarce. In this work, the effects of ZnO nanoparticles, a potent quorum and virulence quencher for the PAO1 strain, were tested in six clinical strains from cystic fibrosis patients, a furanone C-30 resistant clinical strain from urine, two PA14 gallium resistant mutants, a PA14 C-30 resistant mutant and four environmental isolates. ZnO nanoparticles effectively decreased elastase, pyocyanin, and biofilm formation for most of the strains; regardless their origin or their resistance against the canonical quorum quencher C-30 or the novel antimicrobial gallium. The data indicate ZnO nanoparticles may have a broad spectrum for the quorum quenching of relevant strains and that may be an alternative to treat Ps. aeruginosa recalcitrant infections. Virulence inhibition by quorum quenchers in Pseudomonas aeruginosa is usually tested in laboratory strains and studies of their effects in relevant clinical and environmental strains are scarce. This study is significant as the effects of ZnO nanoparticles in QS-dependent virulence factor production were tested in six clinical strains from cystic fibrosis patients, a C-30 resistant clinical strain from urine, two PA14 gallium resistant mutants, a PA14 C-30 resistant mutant, and four environmental isolates. ZnO nanoparticles decreased elastase, pyocyanin, and biofilms for most of the strains; indicating they have broad spectrum and may be an alternative to treat Ps. aeruginosa infections. © 2015 The Society for Applied Microbiology.

  7. Global regulatory pathways and cross-talk control pseudomonas aeruginosa environmental lifestyle and virulence phenotype.

    PubMed

    Coggan, Kimberly A; Wolfgang, Matthew C

    2012-01-01

    Pseudomonas aeruginosa is a metabolically versatile environmental bacterium and an opportunistic human pathogen that relies on numerous signaling pathways to sense, respond, and adapt to fluctuating environmental cues. Although the environmental signals sensed by these pathways are poorly understood, they are largely responsible for determining whether P. aeruginosa adopts a planktonic or sessile lifestyle. These environmental lifestyle extremes parallel the acute and chronic infection phenotypes observed in human disease. In this review, we focus on four major pathways (cAMP/Vfr and c-di-GMP signaling, quorum sensing, and the Gac/Rsm pathway) responsible for sensing and integrating external stimuli into coherent regulatory control at the transcriptional, translational, and post-translational level. A common theme among these pathways is the inverse control of factors involved in promoting motility and acute infection and those associated with biofilm formation and chronic infection. In many instances these regulatory pathways influence one another, forming a complex network allowing P. aeruginosa to assimilate numerous external signals into an integrated regulatory circuit that controls a lifestyle continuum.

  8. Characterization of five newly isolated bacteriophages active against Pseudomonas aeruginosa clinical strains.

    PubMed

    Kwiatek, Magdalena; Mizak, Lidia; Parasion, Sylwia; Gryko, Romuald; Olender, Alina; Niemcewicz, Marcin

    2015-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen that causes serious infections, especially in patients with immunodeficiency. It exhibits multiple mechanisms of resistance, including efflux pumps, antibiotic modifying enzymes and limited membrane permeability. The primary reason for the development of novel therapeutics for P. aeruginosa infections is the declining efficacy of conventional antibiotic therapy. These clinical problems caused a revitalization of interest in bacteriophages, which are highly specific and have very effective antibacterial activity as well as several other advantages over traditional antimicrobial agents. Above all, so far, no serious or irreversible side effects of phage therapy have been described. Five newly purified P. aeruginosa phages named vB_PaeM_WP1, vB_PaeM_WP2, vB_PaeM_WP3, vB_PaeM_WP4 and vB_PaeP_WP5 have been characterized as potential candidates for use in phage therapy. They are representatives of the Myoviridae and Podoviridae families. Their host range, genome size, structural proteins and stability in various physical and chemical conditions were tested. The results of these preliminary investigations indicate that the newly isolated bacteriophages may be considered for use in phagotherapy.

  9. Temperature-sensitive mutants of Pseudomonas aeruginosa: isolation and preliminary immunological evaluation.

    PubMed Central

    Hooke, A M; Arroyo, P J; Oeschger, M P; Bellanti, J A

    1982-01-01

    The immunogenicity of two temperature-sensitive (ts) mutants of Pseudomonas aeruginosa immunotype 1, isolated and characterized for the development of a safe, live vaccine strain, was evaluated in a mouse protection model. One mutant, A/10/25, had a limited "coasting" property (i.e., continued replication for two divisions) at the nonpermissive temperature (36 degrees C), whereas the other mutant, E/9/9, continued replication for five generations after transfer to 36 degrees C. Groups of 3- to 5-week-old ICR mice were immunized intraperitoneally with various doses of the two ts mutants; at various times thereafter, the mice were challenged intraperitoneally with lethal doses of the parental wild type. The more extensive coaster, E/9/9, induced 100% protection at immunizing doses lower than those required for A/10/25 to induce the same protection (1 x 10(8) to 2 x 10(8) and 6 x 10(8) colony-forming units, respectively). Both ts strains induced significant protection for up to 5 weeks after immunization. The results of these studies suggest that the use of P. aeruginosa ts mutants might provide a novel approach to the prevention of P. aeruginosa colonization of patients with cystic fibrosis. PMID:6815088

  10. Crataeva nurvala nanoparticles inhibit virulence factors and biofilm formation in clinical isolates of Pseudomonas aeruginosa.

    PubMed

    Ali, Syed Ghazanfar; Ansari, Mohammad Azam; Khan, Haris M; Jalal, Mohammad; Mahdi, Abbas Ali; Cameotra, Swaranjit Singh

    2017-03-01

    Green synthesized nanoparticles have gained great attention due to their non-toxic and non-hazardous nature. In the present study, bark extract of the medicinal plant in Ayurveda Crataeva nurvala (Buch-Ham) (CN) was chosen for the biosynthesis of silver nanoparticles (AgNPs). These NPs were characterized by Ultra violet visible spectroscopy, Fourier Transform Infra Red, Atomic Force Microscopy, and Transmission Electron Microscopy (TEM). The average particle size of green synthesized CN-AgNPs was 15.2 ± 1.01 nm. Gas chromatography- mass spectrometry analysis of methanolic bark extract involved in the formation of CN-AgNPs revealed lupeol as a major active component. In this study, CN-AgNPs (15 μg ml(-1) ) efficiently suppressed the production of quorum sensing mediated virulence factors viz. pyocyanin, protease, hemolysin, and biofilm formation in Pseudomonas aeruginosa. The pyocyanin production was strongly inhibited (74.64%) followed by proteolysis (47.3%) and hemolysin production (47.7%). However, the biofilm forming ability was maximally reduced up to 79.70%. Moreover, the Confocal Laser Scanning Microscopic Analysis showed that CN-AgNPs inhibit colonization of P. aeruginosa on to the surface. Furthermore, TEM analysis revealed internalization of CN-AgNPs inside the bacterial cell. It is concluded that green synthesized AgNPs have great potential to inhibit virulence factors and biofilm forming ability of drug-resistant clinical isolates of P. aeruginosa.

  11. Phosphate limitation induces the intergeneric inhibition of Pseudomonas aeruginosa by Serratia marcescens isolated from paper machines

    PubMed Central

    Kuo, Pei-An; Kuo, Chih-Horng; Lai, Yiu-Kay; Graumann, Peter L; Tu, Jenn

    2013-01-01

    Phosphate is an essential nutrient for heterotrophic bacteria, affecting bacterioplankton in aquatic ecosystems and bacteria in biofilms. However, the influence of phosphate limitation on bacterial competition and biofilm development in multispecies populations has received limited attention in existing studies. To address this issue, we isolated 13 adhesive bacteria from paper machine aggregates. Intergeneric inhibition of Pseudomonas aeruginosa WW5 by Serratia marcescens WW4 was identified under phosphate-limited conditions, but not in Luria–Bertani medium or M9 minimal medium. The viable numbers of the pure S. marcescens WW4 culture decreased over 3 days in the phosphate-limited medium; however, the mortality of S. marcescens WW4 was significantly reduced when it was co-cultured with P. aeruginosa WW5, which appeared to sustain the S. marcescens WW4 biofilm. In contrast, viable P. aeruginosa WW5 cells immediately declined in the phosphate-limited co-culture. To identify the genetic/inhibitory element(s) involved in this process, we inserted a mini-Tn5 mutant of S. marcescens WW4 that lacked inhibitory effect. The results showed that an endonuclease bacteriocin was involved in this intergeneric inhibition by S. marcescens WW4 under phosphate limitation. In conclusion, this study highlights the importance of nutrient limitation in bacterial interactions and provides a strong candidate gene for future functional characterisation. PMID:23398522

  12. Evaluate the Relationship Between Class 1 Integrons and Drug Resistance Genes in Clinical Isolates of Pseudomonas aeruginosa.

    PubMed

    Hosseini, Seyed Mohammad Javad; Naeini, Niloofar Shoaee; Khaledi, Azad; Daymad, Seyede Fatemeh; Esmaeili, Davoud

    2016-01-01

    The prevalence of resistant Pseudomonas aeruginosa isolates is increasing and it is considered as one of the major public health concerns in the world. The association between integrons and drug resistance has been proven and evidences suggest that integrons are coding and responsible for dissemination of antibiotic resistance among P. aeruginosa isolates. This study is aimed to evaluate the relationship between class 1 integrons and drug resistance genes in clinical isolates of P. aeruginosa from burn patients. 100 isolates of P. aeruginosa were collected from burn patients hospitalized in the skin ward of Shahid Motahari hospital and susceptibility testing was performed by disk diffusion method (Kirby-Bauer). Then DNA was extracted and PCR technique was performed for the detection of class 1 integrons and drug resistance genes. Then data was analyzed using SPSS software. The most effective antibiotic was polymyxin B with sensitivity 100%, and the most resistance was observed to the ciprofloxacin (93%) and amikacin (67%), respectively. The maximum and lowest frequencies of drug resistance genes belonged to the aac (6 ') - 1, VEB-1 with prevalence rate 93% and 10%, respectively. The statistical Chi-square test did not find any significant correlation between class 1 integrons and drug resistance genes (p˃ 0.05). Although no significant correlation between class 1 integrons and drug resistance was observed, but the resistance rate to antibiotics tested among P. aeruginosa isolates was high. So, surveillance, optimization and strict consideration of antimicrobial use and control of infection are necessary.

  13. Detection of Pseudomonas aeruginosa isolates carrying the blaOXA-142 extended-spectrum β-lactamase gene in Taiwan.

    PubMed

    Liu, Chang-Pan; Chen, Te-Li; Wang, Nai-Yu; Chow, Shan-Fan; Lin, Jung-Chung; Yan, Tsong-Rong

    2017-02-01

    The emergence of extended-spectrum β-lactamase (ESBL) OXA-142 gene (blaOXA-142) in Pseudomonas aeruginosa has been reported in Bulgaria and other European countries, but rarely in Asia. From January 2009 to December 2012, 90 P. aeruginosa isolates with reduced susceptibility or resistance to ceftazidime (minimum inhibitory concentration ≥ 8 mg/L) were screened for ESBL and other broad-spectrum β-lactamase genes by polymerase chain reaction and sequencing. Clonal relationship of the isolates was determined by pulsed-field gel electrophoresis. Three isolates were positive for ESBL production, exhibited resistance to ceftazidime, and carried the blaOXA-142 gene. The blaOXA-142 gene was integrated into class 1 integron. Using Southern blot analysis, blaOXA-142-containing integron was found to be located on a plasmid in all three isolates. Eleven strains of P. aeruginosa carrying blaOXA-17 gene were found. The oprD mutation was found in all the 21 ESBL strains of P. aeruginosa. This study confirmed the presence of blaOXA-142-positive P. aeruginosa isolates in Taiwan. Copyright © 2014. Published by Elsevier B.V.

  14. The isolation and characterization of lipopolysaccharides from Microcystis aeruginosa, a prominent toxic water bloom forming cyanobacteria.

    PubMed

    Bláhová, Lucie; Adamovský, Ondřej; Kubala, Lukáš; Švihálková Šindlerová, Lenka; Zounková, Radka; Bláha, Luděk

    2013-12-15

    Massive toxic blooms of cyanobacteria represent a major threat to water supplies worldwide, yet serious gaps exist in understanding their complex toxic effects, including the role of lipopolysaccharides (LPS). The present comparative study focused on the levels and biological activities of LPS isolated from Microcystis aeruginosa, which is one of the most globally distributed toxic species. Using hot phenol extraction, LPS was isolated from 3 laboratory cultures and 11 natural water blooms. It formed 0.2-0.7% of the original dry biomass of the cyanobacteria, based on gravimetry. Additional analyses by commercial anti-LPS ELISA were correlated with gravimetry but showed concentrations that were about 7-times lower, which indicated either impurities in isolated LPS or the poor cross-reactivity of the antibodies used. LPS isolates from M. aeruginosa were potent pyrogens in the traditional Limulus amebocyte lysate (LAL)-test, but comparison with the PyroGene test demonstrated the limited selectivity of LAL with several interferences. The determined pyrogenicity (endotoxin units, EU) ranged from very low values in laboratory cultures (less than 0.003 up to 0.008-EU per 100 pg LPS) to higher values in complex bloom samples (0.01-0.078 EU per 100 pg of LPS), which suggested the role of bloom-associated bacteria in the overall effects. Potent pro-inflammatory effects of the studied LPS from both cultures and bloom samples were observed in a highly-relevant ex vivo human blood model by studying reactive oxygen species production in phagocytes as well as increased productions of interleukin 8, IL-8, and tumor necrosis factor α, TNF-α. LPS from M. aeruginosa seem to modulate several pathways involved in the regulation of both innate immunity and specific responses. In comparison to the standard pathogenic bacterial LPS (World Health Organization Escherichia coli O113:10 endotoxin; activity 1 EU per 100 pg), the studied cyanobacterial samples had pyrogenicity potencies

  15. Decolorization of Distillery Spent Wash Using Biopolymer Synthesized by Pseudomonas aeruginosa Isolated from Tannery Effluent

    PubMed Central

    David, Charles; Arivazhagan, M.; Balamurali, M. N.; Shanmugarajan, Dhivya

    2015-01-01

    A bacterial strain was isolated from tannery effluent which can tolerate high concentrations of potassium dichromate up to 1000 ppm. The isolated microorganism was identified as Pseudomonas aeruginosa by performing biochemical tests and molecular characterization. In the presence of excess of carbohydrate source, which is a physiological stress, this strain produces Polyhydroxybutyrate (PHB). This intracellular polymer, which is synthesized, is primarily a product of carbon assimilation and is employed by microorganisms as an energy storage molecule to be metabolized when other common energy sources are limitedly available. Efforts were taken to check whether the PHB has any positive effect on spent wash decolorization. When a combination of PHB and the isolated bacterial culture was added to spent wash, a maximum color removal of 92.77% was found which was comparatively higher than the color removed when the spent wash was treated individually with the PHB and Pseudomonas aeruginosa. PHB behaved as a support material for the bacteria to bind to it and thus develops biofilm, which is one of the natural physiological growth forms of microorganisms. The bacterial growth in the biofilm and the polymer together acted in synergy, adsorbing and coagulating the pollutants in the form of color pigments. PMID:26504787

  16. Decolorization of Distillery Spent Wash Using Biopolymer Synthesized by Pseudomonas aeruginosa Isolated from Tannery Effluent.

    PubMed

    David, Charles; Arivazhagan, M; Balamurali, M N; Shanmugarajan, Dhivya

    2015-01-01

    A bacterial strain was isolated from tannery effluent which can tolerate high concentrations of potassium dichromate up to 1000 ppm. The isolated microorganism was identified as Pseudomonas aeruginosa by performing biochemical tests and molecular characterization. In the presence of excess of carbohydrate source, which is a physiological stress, this strain produces Polyhydroxybutyrate (PHB). This intracellular polymer, which is synthesized, is primarily a product of carbon assimilation and is employed by microorganisms as an energy storage molecule to be metabolized when other common energy sources are limitedly available. Efforts were taken to check whether the PHB has any positive effect on spent wash decolorization. When a combination of PHB and the isolated bacterial culture was added to spent wash, a maximum color removal of 92.77% was found which was comparatively higher than the color removed when the spent wash was treated individually with the PHB and Pseudomonas aeruginosa. PHB behaved as a support material for the bacteria to bind to it and thus develops biofilm, which is one of the natural physiological growth forms of microorganisms. The bacterial growth in the biofilm and the polymer together acted in synergy, adsorbing and coagulating the pollutants in the form of color pigments.

  17. [Molecular typification of Pseudomonas aeruginosa strains isolated from patients with cystic fibrosis].

    PubMed

    Iglesias, N G; Marengo, J M; Rentería, F; Gatti, B; Segal, E; Semorile, L

    2008-01-01

    Cystic fibrosis is the most frequent lethal genetic disease that affects the caucasian population. The main cause of morbidity is the chronic lung infection, being the infection caused by Pseudomonas aeruginosa the most difficult to eradicate. This bacteria can be acquired in direct form, by person-to-person transfer, or indirectly, by hospital acquired infection. The Centro Provincial de Referencia de Fibrosis Quistica functioning in the Hospital de Niños "Sor María Ludovica", in La Plata, cares almost 220 patients aged two months to 45 years. The life expectancy depends of factors like the early diagnosis of the disease and the later acquisition of the chronic lung infection. The purpose of this work was the molecular typing of P. aeruginosa isolates obtained from cystic fibrosis patients to evaluate the genomic relationship among them. The study was carried out using RAPD-PCR. The analysis showed a great genetic heterogeneity among the isolates. The separation of the patients in groups in accordance with its bacteriology, that implies the attendance in different days and the implementation of isolation (or segregation) measures had demonstrated to be, in addition to other strategies, effective in the reduction of cross infections.

  18. The role of gyrA and parC mutations in fluoroquinolones-resistant Pseudomonas aeruginosa isolates from Iran.

    PubMed

    Nouri, Roghayeh; Ahangarzadeh Rezaee, Mohammad; Hasani, Alka; Aghazadeh, Mohammad; Asgharzadeh, Mohammad

    The aim of this study was to examine mutations in the quinolone-resistance-determining region (QRDR) of gyrA and parC genes in Pseudomonas aeruginosa isolates. A total of 100 clinical P. aeruginosa isolates were collected from different university-affiliated hospitals in Tabriz, Iran. Minimum inhibitory concentrations (MICs) of ciprofloxacin and levofloxacin were evaluated by agar dilution assay. DNA sequences of the QRDR of gyrA and parC were determined by the dideoxy chain termination method. Of the total 100 isolates, 64 were resistant to ciprofloxacin. No amino acid alterations were detected in gyrA or parC genes of the ciprofloxacin susceptible or ciprofloxacin intermediate isolates. Thr-83 → Ile substitution in gyrA was found in all 64 ciprofloxacin resistant isolates. Forty-four (68.75%) of them had additional substitution in parC. A correlation was found between the number of the amino acid alterations in the QRDR of gyrA and parC and the level of ciprofloxacin and levofloxacin resistance of the P. aeruginosa isolates. Ala-88 → Pro alteration in parC was generally found in high level ciprofloxacin resistant isolates, which were suggested to be responsible for fluoroquinolone resistance. These findings showed that in P. aeruginosa, gyrA was the primary target for fluoroquinolone and additional mutation in parC led to highly resistant isolates. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  19. Genotypic and phenotypic relatedness of Pseudomonas aeruginosa isolates among the major cystic fibrosis patient cohort in Italy.

    PubMed

    Cigana, Cristina; Melotti, Paola; Baldan, Rossella; Pedretti, Elisa; Pintani, Emily; Iansa, Patrizia; De Fino, Ida; Favari, Flavio; Bergamini, Gabriella; Tridello, Gloria; Cirillo, Daniela M; Assael, Baroukh M; Bragonzi, Alessandra

    2016-07-11

    Pseudomonas aeruginosa is the predominant pathogen associated with the decline of pulmonary function in cystic fibrosis (CF) patients. Both environment-to-host acquisition and patient-to-patient transmission have been described for P. aeruginosa infection. Epidemic clones and bacterial phenotypic adaptation to the CF lung have been recognised as independent risk factors for disease progression. So far, there is no established link between genotypic prevalence and phenotypic traits. Here, we look at the major CF patient cohort in Italy to identify shared P. aeruginosa clones and associated common phenotypic traits. A comprehensive analysis of P. aeruginosa genotypes to determine the presence of high-risk shared clones and their association to specific phenotypic traits has been performed in a major Italian CF centre. Pulsed-field gel electrophoresis (PFGE) of P. aeruginosa isolates from 338 CF subjects identified 43 profiles shared by two or more patients and 214 profiles exclusive to individual patients. There was no evidence of a P. aeruginosa outbreak, but four most prevalent pulsotypes were detected. Common phenotypic traits were recorded intra-pulsotypes, but we detected heterogeneity inter-pulsotypes. Two of the four major pulsotypes included P. aeruginosa isolates with hallmarks of adaptation to the CF airways, including loss of motility, low production of siderophore, pyocyanin and proteases, and antibiotic resistance. One of these pulsotypes grouped a high percentage of hypermutable isolates. No clear correlation between epidemiological and clinical data was found. We conclude that CF patients of this cohort shared common pulsotypes, but their phenotypic heterogeneity indicates an absence of specific traits associated to P. aeruginosa genotypic prevalence.

  20. Characterization of antibiotic and disinfectant susceptibility profiles among Pseudomonas aeruginosa veterinary isolates recovered during 1994-2003.

    PubMed

    Beier, R C; Foley, S L; Davidson, M K; White, D G; McDermott, P F; Bodeis-Jones, S; Zhao, S; Andrews, K; Crippen, T L; Sheffield, C L; Poole, T L; Anderson, R C; Nisbet, D J

    2015-02-01

    To evaluate susceptibility of Pseudomonas aeruginosa veterinary isolates to antibiotics and disinfectants. Pseudomonas aeruginosa isolates collected from dogs (n = 155) and other animals (n = 20) from sixteen states during 1994-2003 were tested for susceptibility. Most isolates were resistant to twenty-one antimicrobials tested, and the highest prevalence of resistance was to β-lactams (93.8%) and sulphonamides (93.5%). Fluoroquinolone resistance did not increase from 1994 to 2003. Ciprofloxacin and enrofloxacin had a 5 and 16% prevalence of resistance, respectively, while sarafloxacin and nalidixic acid had a prevalence of resistance of 97 and 98%, respectively. Strains were pan-resistant to triclosan and chlorhexidine, were highly resistant to benzalkonium chloride and demonstrated high susceptibility to other disinfectants. Didecyldimethylammonium chloride was the most active ammonium chloride. Inducible resistance was observed to cetyl ammonium halides, chlorhexidine and benzyl ammonium chlorides, which formulate disinfectants used in veterinary clinics and dairies. Organic acid inhibition was associated with the dissociated acid species. Dissociated organic acids appear able to inhibit Ps. aeruginosa, and rates of fluoroquinolone resistance merit sustained companion animal isolate surveillance. This is the first report of Ps. aeruginosa susceptibility to 24 disinfectants and illustrates the high resistance of Ps. aeruginosa to both antibiotics and disinfectants. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

  1. Molecular characterization of carbapenem-resistant Pseudomonas aeruginosa strains isolated from patients with urinary tract infections in Southern Poland.

    PubMed

    Pobiega, Monika; Maciąg, Joanna; Chmielarczyk, Agnieszka; Romaniszyn, Dorota; Pomorska-Wesolowska, Monika; Ziolkowski, Grzegorz; Heczko, Piotr B; Bulanda, Malgorzata; Wojkowska-Mach, Jadwiga

    2015-11-01

    Due to the clinical threat posed by multidrug-resistant (MDR) Pseudomonas aeruginosa and importance of virulence factors produced in infection, 21 carbapenem-resistant P. aeruginosa were analyzed. 42.8% metallo-beta-lactamases-positive strains were identified. 85.7% of strains were meropenem resistant. 14.2% of strains were MDR; 38%, extensively drug-resistant (XDR). ExoY was present in all strains; exoT, in 95.2%; exoS, in 90.5%; exoU, in 47.6%. Eight XDR strains were typed using multilocus sequence typing: 4 as ST235, 2 as ST260, 2 as ST654 and ST234. MDR P. aeruginosa were isolated from hospitalized patients and among those from the community. Our study demonstrates the serious clinical issues posed by MDR P. aeruginosa and underscores the need for new treatment.

  2. Antibacterial effects of water soluble green tea extracts on multi-antibiotic resistant isolates of Pseudomonas aeruginosa.

    PubMed

    Jazani, N Hosseini; Shahabi, Sh; Ali, A Abdi

    2007-05-01

    In this research we evaluated the antibacterial activity of water soluble green tea extracts on 43 hospital isolates of Pseudomonas aeruginosa. A total of 43 strains of Pseudomonas aeruginosa were collected from clinical specimens at two hospitals in Tehran, Iran. The susceptibilities of isolates to different antibiotics were tested using agar disk diffusion method. Antibacterial activity of water soluble green tea extract was measured by Minimum Inhibitory Concentrations (MICs) and Minimum Bactericidal Concentrations (MBCs). 35.6% of isolated strains showed resistance to 5 antibiotics or more and 55.8% of all strains were Multi-Drug Resistant (MDR) strains. The average MICs and MBCs of the extract against all strains of Pseudomonas auroginosa were 2.06 +/- 1.76 and 2.54 +/- 2.22 mg mL(-1) respectively.Our study suggests that green tea has significant activity with bactericidal action on multi-drug resistant strains of Pseudomonas aeruginosa.

  3. Production of metallo-β-lactamase among Pseudomonas aeruginosa strains isolated in the State of Sergipe, Brazil.

    PubMed

    Costa, Lívia Maria do Amorim; Fleming, Maria Emília de Castro Kling; Paula, Geraldo Renato de; Teixeira, Lenise Arneiro; Mondino, Pedro Juan José; de Mondino, Sílvia Susana Bona; Mendonça-Souza, Cláudia Rezende de Vieira

    2015-01-01

    Acquired production of metallo-β-lactamases is an important mechanism of resistance in Pseudomonas aeruginosa. The objective of this study was to investigate the production of metallo-β-lactamase and the genetic diversity among ceftazidime-resistant P. aeruginosa isolates from State of Sergipe, Brazil. Metallo-β-lactamase was investigated using the disk approximation test and polymerase chain reaction (PCR). Genetic diversity was evaluated by pulsed-field gel electrophoresis (PFGE). A total of 48 (51.6%) isolates were resistant to ceftazidime. Six (12.2%) of these were positive for metallo-β-lactamase production. Only two (4.1%) of the ceftazidime-resistant isolates carried the bla SPM-1 gene. Production of metallo-β-lactamases was not the main mechanism of resistance to ceftazidime and carbapenems among P. aeruginosa strains in Sergipe, Brazil.

  4. [The comparison of selected virulence factors in Pseudomonas aeruginosa catheter isolates].

    PubMed

    Olejnízková, Katerina; Holá, Veronika

    2012-05-01

    Healthcare quality improvement brings about an increasing number of invasive diagnostic and therapeutic procedures and thus also an increasing number of high-risk patients prone to hospital infections. Pseudomonas aeruginosa is one of the most commonly isolated nosocomial species and the treatment of the infection is often long and problematic, with frequent recurrences. The pathogenesis of Pseudomonas infection is associated with a range of virulence factors. In the present study, 93 catheter isolates of Pseudomonas aeruginosa were screened for the biofilm formation, motility and secretion of selected extracellular products. A high rate of the strains tested were producers of hemolysins, LasB elastase, and pyoverdines (> 70%). The biofilm formation was detected in 80% of isolates and formation of aerated biofilm was present in 90% of isolates with a positive correlation found between the two types of biofilm formation (p = 0.00583; gamma = 0.551). All strains showed swarming motility, 95% of strains showed swimming motility, and 75% of strains showed twitching motility. Among the virulence factors studied, only pyocyanin and pyochelin were produced by a lower proportion of isolates (< 25%). A positive correlation was seen between the production of some extracellular molecules (pyochelin and pyocyanin, pyocyanin and LasB elastase, and LasB elastase and haemolysins), between biofilm formation and formation of aerated biofilm, and between formation of aerated biofilm and pigments (pyoverdine and pyocyanin) production. On the other hand, a negative correlation was found between biofilm production and LasB elastase production and between the production of biofilm under immersion and pigments (pyoverdine and pyocyanin) production. All correlations are significant at the level p = 0.05, with the correlation coefficient gamma > 0.50.

  5. LasR Variant Cystic Fibrosis Isolates Reveal an Adaptable Quorum-Sensing Hierarchy in Pseudomonas aeruginosa.

    PubMed

    Feltner, John B; Wolter, Daniel J; Pope, Christopher E; Groleau, Marie-Christine; Smalley, Nicole E; Greenberg, E Peter; Mayer-Hamblett, Nicole; Burns, Jane; Déziel, Eric; Hoffman, Lucas R; Dandekar, Ajai A

    2016-10-04

    Chronic Pseudomonas aeruginosa infections cause significant morbidity in patients with cystic fibrosis (CF). Over years to decades, P. aeruginosa adapts genetically as it establishes chronic lung infections. Nonsynonymous mutations in lasR, the quorum-sensing (QS) master regulator, are common in CF. In laboratory strains of P. aeruginosa, LasR activates transcription of dozens of genes, including that for another QS regulator, RhlR. Despite the frequency with which lasR coding variants have been reported to occur in P. aeruginosa CF isolates, little is known about their consequences for QS. We sequenced lasR from 2,583 P. aeruginosa CF isolates. The lasR sequences of 580 isolates (22%) coded for polypeptides that differed from the conserved LasR polypeptides of well-studied laboratory strains. This collection included 173 unique lasR coding variants, 116 of which were either missense or nonsense mutations. We studied 31 of these variants. About one-sixth of the variant LasR proteins were functional, including 3 with nonsense mutations, and in some LasR-null isolates, genes that are LasR dependent in laboratory strains were nonetheless expressed. Furthermore, about half of the LasR-null isolates retained RhlR activity. Therefore, in some CF isolates the QS hierarchy is altered such that RhlR quorum sensing is independent of LasR regulation. Our analysis challenges the view that QS-silent P. aeruginosa is selected during the course of a chronic CF lung infection. Rather, some lasR sequence variants retain functionality, and many employ an alternate QS strategy involving RhlR.

  6. LasR Variant Cystic Fibrosis Isolates Reveal an Adaptable Quorum-Sensing Hierarchy in Pseudomonas aeruginosa

    PubMed Central

    Feltner, John B.; Wolter, Daniel J.; Pope, Christopher E.; Groleau, Marie-Christine; Smalley, Nicole E.; Greenberg, E. Peter; Mayer-Hamblett, Nicole; Burns, Jane; Hoffman, Lucas R.

    2016-01-01

    ABSTRACT Chronic Pseudomonas aeruginosa infections cause significant morbidity in patients with cystic fibrosis (CF). Over years to decades, P. aeruginosa adapts genetically as it establishes chronic lung infections. Nonsynonymous mutations in lasR, the quorum-sensing (QS) master regulator, are common in CF. In laboratory strains of P. aeruginosa, LasR activates transcription of dozens of genes, including that for another QS regulator, RhlR. Despite the frequency with which lasR coding variants have been reported to occur in P. aeruginosa CF isolates, little is known about their consequences for QS. We sequenced lasR from 2,583 P. aeruginosa CF isolates. The lasR sequences of 580 isolates (22%) coded for polypeptides that differed from the conserved LasR polypeptides of well-studied laboratory strains. This collection included 173 unique lasR coding variants, 116 of which were either missense or nonsense mutations. We studied 31 of these variants. About one-sixth of the variant LasR proteins were functional, including 3 with nonsense mutations, and in some LasR-null isolates, genes that are LasR dependent in laboratory strains were nonetheless expressed. Furthermore, about half of the LasR-null isolates retained RhlR activity. Therefore, in some CF isolates the QS hierarchy is altered such that RhlR quorum sensing is independent of LasR regulation. Our analysis challenges the view that QS-silent P. aeruginosa is selected during the course of a chronic CF lung infection. Rather, some lasR sequence variants retain functionality, and many employ an alternate QS strategy involving RhlR. PMID:27703072

  7. Intrinsic and environmental mutagenesis drive diversification and persistence of Pseudomonas aeruginosa in chronic lung infections.

    PubMed

    Rodríguez-Rojas, Alexandro; Oliver, Antonio; Blázquez, Jesús

    2012-01-01

    Pseudomonas aeruginosa is a versatile opportunistic pathogen causing a wide variety of hospital-acquired acute infections in immunocompromised patients as well as chronic respiratory infections in patients suffering from cystic fibrosis or other chronic respiratory diseases. Several traits contribute to its ability to colonize and persist in the lungs of chronically infected patients, including development of high resistance to antimicrobials and hypermutability, biofilm growth, and alginate hyperproduction, or a customized pathogenicity, which may include the loss of classical virulence factors and metabolic changes. Here we argue that a combination of both intrinsic and environmental mutagenesis leads to a high number of mutant variants in the population. The conducive environment then triggers a positive feedback loop leading to adaptation and persistence of P. aeruginosa, rendering these chronic infections almost impossible to eradicate.

  8. Association of alginate from Pseudomonas aeruginosa with two forms of heparin-binding lectin isolated from rat lung.

    PubMed Central

    Ceri, H; McArthur, H A; Whitfield, C

    1986-01-01

    An endogenous heparin-binding lectin activity isolated from rat lung was separated into two distinct isolectin forms which showed subtle changes in carbohydrate specificity. The two lectin forms displayed different specificities toward alginic acid-purified cystic fibrosis isolates of Pseudomonas aeruginosa when assayed by inhibition of both hemagglutination and [3H]heparin binding. This ability of isolectin forms to show higher affinity toward alginic acid from certain P. aeruginosa strains may suggest that there is a selective mechanism in the colonization of patients with cystic fibrosis. PMID:3079726

  9. Investigation of a Large Collection of Pseudomonas aeruginosa Bacteriophages Collected from a Single Environmental Source in Abidjan, Côte d’Ivoire

    PubMed Central

    Essoh, Christiane; Latino, Libera; Midoux, Cédric; Blouin, Yann; Loukou, Guillaume; Nguetta, Simon-Pierre A.; Lathro, Serge; Cablanmian, Arsher; Kouassi, Athanase K.; Vergnaud, Gilles; Pourcel, Christine

    2015-01-01

    Twenty two distinct bacteriophages were isolated from sewage water from five locations in the city of Abidjan, Côte d'Ivoire over a two-year period, using a collection of Pseudomonas aeruginosa strains with diverse genotypes. The phages were characterized by their virulence spectrum on a panel of selected P. aeruginosa strains from cystic fibrosis patients and by whole genome sequencing. Twelve virions representing the observed diversity were visualised by electron microscopy. The combined observations showed that 17 phages, distributed into seven genera, were virulent, and that five phages were related to temperate phages belonging to three genera. Some showed similarity with known phages only at the protein level. The vast majority of the genetic variations among virulent phages from the same genus resulted from seemingly non-random horizontal transfer events, inside a population of P. aeruginosa phages with limited diversity. This suggests the existence of a single environmental reservoir or ecotype in which continuous selection is taking place. In contrast, mostly point mutations were observed among phages potentially capable of lysogenisation. This is the first study of P. aeruginosa phage diversity in an African city and it shows that a large variety of phage species can be recovered in a limited geographical site at least when different bacterial strains are used. The relative temporal and spatial stability of the Abidjan phage population might reflect equilibrium in the microbial community from which they are released. PMID:26115051

  10. Pseudomonas aeruginosa inhibits the growth of Scedosporium aurantiacum, an opportunistic fungal pathogen isolated from the lungs of cystic fibrosis patients

    PubMed Central

    Kaur, Jashanpreet; Pethani, Bhavin P.; Kumar, Sheemal; Kim, Minkyoung; Sunna, Anwar; Kautto, Liisa; Penesyan, Anahit; Paulsen, Ian T.; Nevalainen, Helena

    2015-01-01

    The filamentous fungus Scedosporium aurantiacum and the bacterium Pseudomonas aeruginosa are opportunistic pathogens isolated from lungs of the cystic fibrosis (CF) patients. P. aeruginosa has been known to suppress the growth of a number of CF related fungi such as Aspergillus fumigatus, Candida albicans, and Cryptococcus neoformans. However, the interactions between P. aeruginosa and S. aurantiacum have not been investigated in depth. Hence we assessed the effect of P. aeruginosa reference strain PAO1 and two clinical isolates PASS1 and PASS2 on the growth of two clinical S. aurantiacum isolates WM 06.482 and WM 08.202 using solid plate assays and liquid cultures, in a synthetic medium mimicking the nutrient condition in the CF sputum. Solid plate assays showed a clear inhibition of growth of both S. aurantiacum strains when cultured with P. aeruginosa strains PASS1 and PAO1. The inhibitory effect was confirmed by confocal microscopy. In addition to using chemical fluorescent stains, strains tagged with yfp (P. aeruginosa PASS1) and mCherry (S. aurantiacum WM 06.482) were created to facilitate detailed microscopic observations on strain interaction. To our knowledge, this is the first study describing successful genetic transformation of S. aurantiacum. Inhibition of growth was observed only in co-cultures of P. aeruginosa and S. aurantiacum; the cell fractions obtained from independent bacterial monocultures failed to initiate a response against the fungus. In the liquid co-cultures, biofilm forming P. aeruginosa strains PASS1 and PAO1 displayed higher inhibition of fungal growth when compared to PASS2. No change was observed in the inhibition pattern when direct cell contact between the bacterial and fungal strains was prevented using a separation membrane suggesting the involvement of extracellular metabolites in the fungal inhibition. However, one of the most commonly described bacterial virulence factors, pyocyanin, had no effect against either of the S

  11. Pseudomonas aeruginosa inhibits the growth of Scedosporium aurantiacum, an opportunistic fungal pathogen isolated from the lungs of cystic fibrosis patients.

    PubMed

    Kaur, Jashanpreet; Pethani, Bhavin P; Kumar, Sheemal; Kim, Minkyoung; Sunna, Anwar; Kautto, Liisa; Penesyan, Anahit; Paulsen, Ian T; Nevalainen, Helena

    2015-01-01

    The filamentous fungus Scedosporium aurantiacum and the bacterium Pseudomonas aeruginosa are opportunistic pathogens isolated from lungs of the cystic fibrosis (CF) patients. P. aeruginosa has been known to suppress the growth of a number of CF related fungi such as Aspergillus fumigatus, Candida albicans, and Cryptococcus neoformans. However, the interactions between P. aeruginosa and S. aurantiacum have not been investigated in depth. Hence we assessed the effect of P. aeruginosa reference strain PAO1 and two clinical isolates PASS1 and PASS2 on the growth of two clinical S. aurantiacum isolates WM 06.482 and WM 08.202 using solid plate assays and liquid cultures, in a synthetic medium mimicking the nutrient condition in the CF sputum. Solid plate assays showed a clear inhibition of growth of both S. aurantiacum strains when cultured with P. aeruginosa strains PASS1 and PAO1. The inhibitory effect was confirmed by confocal microscopy. In addition to using chemical fluorescent stains, strains tagged with yfp (P. aeruginosa PASS1) and mCherry (S. aurantiacum WM 06.482) were created to facilitate detailed microscopic observations on strain interaction. To our knowledge, this is the first study describing successful genetic transformation of S. aurantiacum. Inhibition of growth was observed only in co-cultures of P. aeruginosa and S. aurantiacum; the cell fractions obtained from independent bacterial monocultures failed to initiate a response against the fungus. In the liquid co-cultures, biofilm forming P. aeruginosa strains PASS1 and PAO1 displayed higher inhibition of fungal growth when compared to PASS2. No change was observed in the inhibition pattern when direct cell contact between the bacterial and fungal strains was prevented using a separation membrane suggesting the involvement of extracellular metabolites in the fungal inhibition. However, one of the most commonly described bacterial virulence factors, pyocyanin, had no effect against either of the S

  12. Isolation of the Autoinducer-Quenching Strain that Inhibits LasR in Pseudomonas aeruginosa

    PubMed Central

    Weng, Lixing; Zhang, Yuqian; Yang, Yuxiang; Wang, Lianhui

    2014-01-01

    Quorum sensing (QS) has been recognized as a general phenomenon in microorganisms and plays an important role in many pathogenic bacteria. In this report, we used the Agrobacterium tumefaciens biosensor strain NT1 to rapidly screen for autoinducer-quenching inhibitors from bacteria. After initial screening 5389 isolates obtained from land and beach soil, 53 putative positive strains were identified. A confirmatory bioassay was carried out after concentrating the putative positive culture supernatant, and 22 strains were confirmed to have anti-LasR activity. Finally, we determined the strain JM2, which could completely inhibit biofilm formation of Pseudomonas aeruginosa PAO1, belonged to the genus Pseudomonas by analysis of 16S rDNA. Partially purified inhibitor factor(s) F5 derived from culture supernatants specifically inhibited LasR-controlled elastase and protease in wild type P. aeruginosa PAO1 by 68% and 73%, respectively, without significantly affecting growth; the rhl-controlled pyocyanin and rhamnolipids were inhibited by 54% and 52% in the presence of 100 μg/mL of F5. The swarming motility and biofilm of PAO1 were also inhibited by F5. Real time RT-PCR on samples from 100 μg/mL F5-treated P. aeruginosa showed downregulation of autoinducer synthase (LasRI and rhlI) and cognate receptor (lasR and rhlR) genes by 50%, 28%, 48%, and 29%, respectively. These results provide compelling evidence that the F5 inhibitor(s) interferes with the las system and significantly inhibits biofilm formation. PMID:24736783

  13. [Degradation characteristics of naphthalene with a Pseudomonas aeruginosa strain isolated from soil contaminated by diesel].

    PubMed

    Liu, Wen-Chao; Wu, Bin-Bin; Li, Xiao-Sen; Lu, Dian-Nan; Liu, Yong-Min

    2015-02-01

    Abstract: A naphthalene-degrading bacterium (referred as HD-5) was isolated from the diesel-contaminated soil and was assigned to Pseudomonas aeruginosa according to 16S rDNA sequences analysis. Gene nah, which encodes naphthalene dioxygenase, was identified from strain HD-5 by PCR amplification. Different bioremediation approaches, including nature attenuation, bioaugmentation with strain Pseudomonas aeruginosa, biostimulation, and an integrated degradation by bioaugmentation and biostimulation, were evaluated for their effectiveness in the remediating soil containing 5% naphthalene. The degradation rates of naphthalene in the soil were compared among the different bioremediation approaches, the FDA and dehydrogenase activity in bioremediation process were measured, and the gene copy number of 16S rRNA and nah in soil were dynamically monitored using real-time PCR. It was shown that the naphthalene removal rate reached 71.94%, 62.22% and 83.14% in approaches of bioaugmentation (B), biostimulation(S) and integrated degradation composed of bioaugmentation and biostimulation (BS), respectively. The highest removal rate of naphthalene was achieved by using BS protocol, which also gives the highest FDA and dehydrogenase activity. The gene copy number of 16S rRNA and nah in soil increased by about 2.67 x 10(11) g(-1) and 8.67 x 10(8) g(-1) after 31 days treatment using BS protocol. Above-mentioned results also demonstrated that the screened bacterium, Pseudomonas aeruginosa, could grow well in naphthalene-contaminated soil and effectively degrade naphthalene, which is of fundamental importance for bioremediation of naphthalene-contaminated soil.

  14. Distribution of Pseudomonas-Derived Cephalosporinase and Metallo-β-Lactamases in Carbapenem-Resistant Pseudomonas aeruginosa Isolates from Korea.

    PubMed

    Cho, Hye Hyun; Kwon, Gye Cheol; Kim, Semi; Koo, Sun Hoe

    2015-07-01

    The emergence of carbapenem resistance among Pseudomonas aeruginosa is an increasing problem in many parts of the world. In particular, metallo-β-lactamases (MBLs) and AmpC β- lactamases are responsible for high-level resistance to carbapenem and cephalosporin. We studied the diversity and frequency of β-lactamases and characterized chromosomal AmpC β- lactamase from carbapenem-resistant P. aeruginosa isolates. Sixty-one carbapenem-resistant P. aeruginosa isolates were collected from patients in a tertiary hospital in Daejeon, Korea, from January 2011 to June 2014. Minimum inhibitory concentrations (MICs) of four antimicrobial agents were determined using the agar-dilution method. Polymerase chain reaction and sequencing were used to identify the various β-lactamase genes, class 1 integrons, and chromosomally encoded and plasmid-mediated ampC genes. In addition, the epidemiological relationship was investigated by multilocus sequence typing. Among 61 carbapenem-resistant P. aeruginosa isolates, 25 isolates (41.0%) were MBL producers. Additionally, 30 isolates producing PDC (Pseudomonas-derived cephalosporinase)-2 were highly resistant to ceftazidime (MIC50 = 256 μg/ml) and cefepime (MIC50 = 256 μg/ml). Of all the PDC variants, 25 isolates harboring MBL genes showed high levels of cephalosporin and carbapenem resistance, whereas 36 isolates that did not harbor MBL genes revealed relatively low-level resistance (ceftazidime, p < 0.001; cefepime, p < 0.001; imipenem, p = 0.003; meropenem, p < 0.001). The coexistence of MBLs and AmpC β-lactamases suggests that these may be important contributing factors for cephalosporin and carbapenem resistance. Therefore, efficient detection and intervention to control drug resistance are necessary to prevent the emergence of P. aeruginosa possessing this combination of β-lactamases.

  15. Exposure of Pseudomonas aeruginosa to green tea polyphenols enhances the tolerance to various environmental stresses.

    PubMed

    Liu, Xiaoxiang; Li, Jianrong; Yang, Yi; Chen, Xiaoqiang

    2012-12-01

    Green tea polyphenols (GTP) are widely used as food preservatives and are considered to be extremely safe. However, the bacterial response to GTP has not been well studied. Here we investigated whether short exposure of Pseudomonas aeruginosa to sub-lethal dose of GTP could lead to cross-resistance to some environmental stresses. One-hour exposure of P. aeruginosa to 1 mg/ml GTP significantly increased the tolerance to oxidants (2 mM H(2)O(2), 4 mM tert-butylhydroperoxide), low pH solution (pH 4.0) containing various organic acids (60 mM citric, acetic, propionic or lactic acid) and other stress conditions (47 °C, 25 % NaCl, 12 % ethanol and 150 μg/ml crystal violet). The development of H(2)O(2) tolerance in GTP-exposed cells was prevented by chloramphenicol, a well-known inhibitor of protein synthesis in prokaryotic cells. Furthermore, we observed significantly increased catalase activity after GTP exposure, suggesting that P. aeruginosa develops GTP-induced cross-resistance by increasing synthesis of protective protein. These observations raise concerns over the underlying risks associated with using GTP as food preservatives.

  16. Aquatic environmental safety assessment and inhibition mechanism of chemicals for targeting Microcystis aeruginosa.

    PubMed

    Yu, Xiao-Bo; Hao, Kai; Ling, Fei; Wang, Gao-Xue

    2014-11-01

    Cyanobacteria are a diverse group of Gram-negative bacteria that produce an array of secondary compounds with selective bioactivity against vertebrates, invertebrates, fungi, bacteria and cell lines. Recently the main methods of controlling cyanobacteria are using chemicals, medicinal plants and microorganism but fewer involved the safety research in hydrophytic ecosystems. In search of an environmentally safe compound, 53 chemicals were screened against the developed heavy cyanobacteria bloom Microcystis aeruginosa using coexistence culture system assay. The results of the coexistence assay showed that 9 chemicals inhibited M. aeruginosa effectively at 20 mg L(-1) after 7 days of exposure. Among them dimethomorph, propineb, and paraquat were identified that they are safe for Chlorella vulgaris, Scenedesmus obliquus, Carassius auratus (Goldfish) and Bacillus subtilis within half maximal effective concentration (EC50) values 5.2, 4.2 and 0.06 mg L(-1) after 7 days, respectively. Paraquat as the positive control observed to be more efficient than the other compounds with the inhibitory rate (IR) of 92% at 0.5 mg L(-1). For the potential inhibition mechanism, the chemicals could destroy the cell ultrastructure in different speed. The safety assay proved dimethomorph, propineb and paraquat as harmless formulations or products having potential value in M. aeruginosa controlling, with the advantage of its cell morphology degrading ability.

  17. Molecular detection of virulence genes in Pseudomonas aeruginosa isolated from children with Cystic Fibrosis and burn wounds in Iran.

    PubMed

    Faraji, Fatemeh; Mahzounieh, Mohammadreza; Ebrahimi, Azizollah; Fallah, Fatemeh; Teymournejad, Omid; Lajevardi, Behnaz

    2016-10-01

    Pseudomonas aeruginosa possesses various virulence factors which contribute to the bacterial invasion and toxicity. Moreover, children suffered from Cystic Fibrosis (CF) and burn wounds are at a high risk of various bacterial infections. The aim of this study was to determine the prevalence of virulent genes in P. aeruginosa isolated from children with CF and burn wounds and comparing their virulence genes to figure out the role of every virulent factor in the infections. P. aeruginosa were isolated from sputum, oropharyngeal swabs, and broncho-alveolar lavage (BAL) specimens from CF and burn wounds between June 2013 and June 2014 in Tehran's hospitals. Bacterial genomic DNAs were extracted and uniplex, duplex and multiplex PCR were performed for detection of toxA, algD and plcN, exoS, lasB, plcH genes, respectively. The prevalence rate of virulence genes in P. aeruginosa isolated from CF was; toxA (63.1%), algD (64.6%), plcH (87.7%), plcN (60%), lasB (95.4%) and exoS (70.8%) and virulence genes in P. aeruginosa from burn patients were: toxA (36.9%), algD (70.1%), plcH (79%), plcN (63.1%), lasB (82%) and exoS (21.1%). The prevalence of three virulent genes in P. aeruginosa was higher in CF comparing to burn wound infections. We found that the number of toxA, lasB and exoS were significantly higher in the bacteria which were isolated from children with CF. This finding shows that these virulence factors play an important role in CF infections by P. aeroginosa. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Characterization of Pseudomonas aeruginosa strains isolated from burned patients hospitalized in a major burn center in Tehran, Iran.

    PubMed

    Ranjbar, Reza; Owlia, Parviz; Saderi, Horie; Mansouri, Sadegh; Jonaidi-Jafari, Nematollah; Izadi, Morteza; Farshad, Shohreh; Arjomandzadegan, Mohammad

    2011-01-01

    Pseudomonas aeruginosa is an important life-threatening nosocomial pathogen and plays a prominent role in serious infections in burned patients. The current study was undertaken to characterize P. aeruginosa strains isolated from burned patients in Tehran, Iran. The study was conducted in a major burn center in Tehran, Iran in 2007. A total of seventy specimens obtained from different clinical origin with positive culture results for P. aeruginosa were included in the study. Antimicrobial susceptibility test was performed according to the standard CLSI guideline. The relationship between the strains was also determined using antimicrobial drug resistance pattern analysis and plasmid profiling. All strains were multi drug resistant. The percentage of resistance to tested antibiotics was: imipenem 97.5%, amikacin 90%, piperacillin 87.5%, ceftizoxime 72.7%, gentamicin 67.5%, ciprofloxacin 65%, ceftriaxone 60%, and ceftazidime 57.5%. Thirteen resistant phenotypes were recognized, R3 (TET, IPM, AMK, CIP, PIP, GM, CAZ, CRO, CT) was the predominant resistance pattern seen in 27.5% of isolates. Results obtained from E-test showed that 100% of P. aeruginosa strains were resistant to cefoxitin, 97% to cefotetan, 93% to ticarcillin, 89% to ticarcillin/clav, 76% to gentamicin and imipenem, 63% to piperacillin, 49% to tetracycline, and 20% to meropenem. Nine different plasmid profiles were observed among the strains. The current study showed an increase rate of resistance for some antibiotics tested among P. aeruginosa strains isolated from burned patients in Tehran. A combination of antibiotic susceptibility testing and profile plasmid analysis, which are relatively cheap and available methods, showed to be useful to characterize the clinical strains of P. aeruginosa isolated from burned patients in Iran.

  19. Isolation and characterization of two bacteriophages with strong in vitro antimicrobial activity against Pseudomonas aeruginosa isolated from dogs with ocular infections.

    PubMed

    Santos, Thiago M A; Ledbetter, Eric C; Caixeta, Luciano S; Bicalho, Marcela L S; Bicalho, Rodrigo C

    2011-08-01

    To isolate and characterize bacteriophages with strong in vitro lytic activity against various pathogenic Pseudomonas aeruginosa strains isolated from dogs with ocular infections. 26 genetically distinct P aeruginosa isolates. P aeruginosa strains were derived from dogs with naturally acquired ulcerative keratitis. From a large-scale screening for bacteriophages with potential therapeutic benefit against canine ocular infections, 2 bacteriophages (P2S2 and P5U5) were selected; host ranges were determined, and phage nucleic acid type and genetic profile were identified via enzymatic digestion. Electron microscopy was used to characterize bacteriophage ultrastructure. Bacteriophage temperature and pH stabilities were assessed by use of double-layer agar overlay titration. A cocultivation assay was used to evaluate the effect of the bacteriophages on bacterial host growth. P5U5 was active against all P aeruginosa isolates, whereas P2S2 formed lytic plaques on plates of 21 (80.8%) isolates. For each bacteriophage, the genomic nucleic acid was DNA; each was genetically distinct. Ultrastructurally, P2S2 and P5U5 appeared likely to belong to the Podoviridae and Siphoviridae families, respectively. The bacteriophages were stable within a pH range of 4 to 12; however, titers of both bacteriophages decreased following heating for 10 to 50 minutes at 45° or 60°C. Growth of each P aeruginosa isolate was significantly inhibited in coculture with P2S2 or P5U5; the dose response was related to the plaque-forming unit-to-CFU ratios. Bacteriophages P2S2 and P5U5 appear to be good candidates for phage treatment of infection caused by pathogenic P aeruginosa in dogs.

  20. Biofilm formation abilities and disinfectant-resistance of Pseudomonas aeruginosa isolated from cockroaches captured in hospitals.

    PubMed

    Saitou, Keiko; Furuhata, Katsunori; Kawakami, Yasushi; Fukuyama, Masafumi

    2009-06-01

    Forty-five strains of Pseudomonas aeruginosa isolated from cockroaches captured in hospitals were investigated with regard to their biofilm-forming ability and resistance to various disinfectants in various cellular states. The hydrophobicity value varied among the test strains from 0.001 to 0.241, and the mean +/- standard deviation (SD) was 0.101 +/- 0.074. The relative viscosity of the extracellular product was measured. All test strains produced a mucous substance, and the value was 1.05-1.30 (mean +/- SD: 1.11 +/- 0.06), showing that all test strains had a biofilm-forming ability. Bactericidal experiments were performed using 6 disinfectants: ethanol, Hibitane, Isojin, Osvan, Tego 51, and Welpas. When bacteria in suspension were exposed to the disinfectants for 1 min (suspension test), 5 of the 6 disinfectants excluding Tego 51 completely killed all test strains, showing high bactericidal effects. In contrast, when adherent bacteria were exposed to the disinfectants for 1 min (adhesion test), the killing rate by Welpas was 100%, but those by Isojin and ethanol were lower (88.9 and 60.0%, respectively), that by Osvan was only 4.4%, and no bacteria were killed by Hibitane or Tego 51. These findings showed that the bactericidal effects markedly decreased in the case of adherent P. aeruginosa.

  1. A thermo-stable lysine aminopeptidase from Pseudomonas aeruginosa: Isolation, purification, characterization, and sequence analysis.

    PubMed

    Wu, Yan Tao; Zhou, Nan Di; Zhou, Zhe Min; Gao, Xin Xing; Tian, Ya Ping

    2014-10-01

    Pseudomonas aeruginosa NJ-814, isolated from garden soil, produced an extracellular aminopeptidase that was purified using ammonium sulfate precipitation and ion exchange chromatography. The purity was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and the Mr value of the enzyme was estimated to be 55 kDa. The purified enzyme shows maximum activity at pH 9.0 and 80 °C. It exhibits high thermo-stability. Half of the activity can remain after incubation at 80 °C for 119 min. It is stable within pH range of 7.5-10.5. It is strongly activated by Co(2+) and inhibited by Fe(2+) , Cu(2+) , Ni(2+) , Zn(2+) , and ethylene diamine tetraacetic acid (EDTA). The specificity of the enzyme was investigated. Within several aminoacyl-p-nitroanilines (AA-pNA), Lys-pNA is proven to be the optimal substrate. The Michaelis-Menten constant (Km ) of the enzyme for Lys-pNA and Leu-pNA were 2.32 and 9.41 mM, respectively. Peptide map fingerprinting shows that the sequence of the enzyme is highly similar to aminopeptidase Y from P. aeruginosa 18A. It can be speculated that this enzyme is a Zn(2+) -dependent enzyme and contains two zinc ions in its active site.

  2. Antimicrobial susceptibility of Pseudomonas aeruginosa isolates from dogs with otitis externa.

    PubMed

    Mekić, S; Matanović, K; Šeol, B

    2011-07-30

    Pseudomonas aeruginosa is a common cause of otitis externa in dogs, and treatment of these infections is becoming problematic because of the increasing number of multiresistant strains. The aim of the present study was to compare the in vitro activities of cefepime, ceftazidime, enrofloxacin, ciprofloxacin, gentamicin and ticarcillin/clavulanic acid against 104 strains of P aeruginosa isolated from dogs with otitis externa. Antimicrobial susceptibility and minimum inhibitory concentrations, in µg/ml, were evaluated by the E test (bioMérieux). The most active compound was ceftazidime, with 100 per cent efficiency. The majority of tested strains were susceptible to ticarcillin/clavulanic acid (89.4 per cent), followed by ciprofloxacin (88.5 per cent) and cefepime (60.6 per cent). The highest resistance was observed to enrofloxacin (51.9 per cent) and gentamicin (43.3 per cent). Large numbers of strains were intermediately susceptible to antibiotics registered for use in veterinary medicine in Croatia--enrofloxacin (47.1 per cent) and gentamicin (41.3 per cent).

  3. Effect of airway Pseudomonas aeruginosa isolation and infection on steady-state bronchiectasis in Guangzhou, China

    PubMed Central

    Guan, Wei-Jie; Gao, Yong-Hua; Xu, Gang; Lin, Zhi-Ya; Tang, Yan; Li, Hui-Min; Li, Zhi-Min; Zheng, Jin-Ping

    2015-01-01

    Background Current status of Pseudomonas aeruginosa (PA) infection in clinically stable bronchiectasis in mainland China remains unclear. Objective To compare the inflammation and lung function impairment in bronchiectasis patients isolated or infected with PA, potentially pathogenic microorganisms (PPMs) and commensals, and to identify factors associated with PA isolation and infection. Methods Patients with steady-state bronchiectasis and healthy subjects were recruited. Peripheral blood and sputum were sampled to determine inflammatory markers and bacterial loads in steady-state bronchiectasis and health. Spirometry and diffusing capacity were also measured. Results We enrolled 144 bronchiectasis patients and 23 healthy subjects. PA isolation and infection accounted for 44 and 39 patients, who demonstrated significant inflammatory responses and markedly impaired spirometry, but not diffusing capacity, compared with healthy subjects and patients isolated with other PPMs and commensals (all P<0.05). Except for heightened sputum inflammatory responses, there were no notable differences in serum inflammation and lung function as with the increased density of PA. Female gender [odds ratio (OR): 3.10 for PA isolation; OR: 3.74 for PA infection], 4 or more exacerbations within 2 years (OR: 3.74 for PA isolation, OR: 2.95 for PA infection) and cystic bronchiectasis (OR: 3.63 for PA isolation, OR: 4.47 for PA infection) were the factors consistently associated with PA isolation and infection. Conclusions PA elicits intense inflammation and lung function impairment in steady-state bronchiectasis. The density of PA does not correlate with most clinical indices. PA infection is associated with females, frequent exacerbations and cystic bronchiectasis. PMID:25973228

  4. Pseudomonas aeruginosa variants isolated from patients with cystic fibrosis are killed by a bactericidal protein from human polymorphonuclear leukocytes.

    PubMed Central

    Siefferman, C M; Regelmann, W E; Gray, B H

    1991-01-01

    The susceptibility of paired mucoid and nonmucoid variants of Pseudomonas aeruginosa isolated from 13 patients with cystic fibrosis (CF) to killing by a 55,000-Da bactericidal protein (BP55) from human polymorphonuclear leukocytes was studied. Mucoid and nonmucoid variants were equally sensitive to killing by BP55 at both pH 5.6 and pH 7.2. Eleven of the isolates were resistant to the bactericidal activity of 10% normal human serum but were as sensitive as the serum-sensitive isolates to BP55. Similarly, the 15 isolates with lipopolysaccharides (LPS) containing O-polysaccharide side chains (smooth LPS) were as sensitive to BP55 as those isolates with rough LPS.P. aeruginosa isolates from patients in poor clinical condition were more likely to have LPS of the smooth type and to be resistant to killing by 10% human serum than the isolates from patients in good clinical condition. We have concluded that the susceptibility of the P. aeruginosa isolates from patients with CF to killing by BP55 does not correlate with mucoid or nonmucoid variations, with the presence or absence of smooth LPS, or with the sensitivity or resistance to killing by normal human serum. Images PMID:1903774

  5. Molecular Epidemiology of Mutations in Antimicrobial Resistance Loci of Pseudomonas aeruginosa Isolates from Airways of Cystic Fibrosis Patients.

    PubMed

    Greipel, Leonie; Fischer, Sebastian; Klockgether, Jens; Dorda, Marie; Mielke, Samira; Wiehlmann, Lutz; Cramer, Nina; Tümmler, Burkhard

    2016-11-01

    The chronic airway infections with Pseudomonas aeruginosa in people with cystic fibrosis (CF) are treated with aerosolized antibiotics, oral fluoroquinolones, and/or intravenous combination therapy with aminoglycosides and β-lactam antibiotics. An international strain collection of 361 P. aeruginosa isolates from 258 CF patients seen at 30 CF clinics was examined for mutations in 17 antimicrobial susceptibility and resistance loci that had been identified as hot spots of mutation by genome sequencing of serial isolates from a single CF clinic. Combinatorial amplicon sequencing of pooled PCR products identified 1,112 sequence variants that were not present in the genomes of representative strains of the 20 most common clones of the global P. aeruginosa population. A high frequency of singular coding variants was seen in spuE, mexA, gyrA, rpoB, fusA1, mexZ, mexY, oprD, ampD, parR, parS, and envZ (amgS), reflecting the pressure upon P. aeruginosa in lungs of CF patients to generate novel protein variants. The proportion of nonneutral amino acid exchanges was high. Of the 17 loci, mexA, mexZ, and pagL were most frequently affected by independent stop mutations. Private and de novo mutations seem to play a pivotal role in the response of P. aeruginosa populations to the antimicrobial load and the individual CF host. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  6. 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

  7. Draft Genome Sequence of Pseudomonas aeruginosa Strain N002, Isolated from Crude Oil-Contaminated Soil from Geleky, Assam, India

    PubMed Central

    Roy, Abhjit Sarma; Baruah, Reshita; Gogoi, Dhrubajyoti; Borah, Maina

    2013-01-01

    Here, we report the draft genome sequence of crude oil-degrading Pseudomonas aeruginosa strain N002, isolated from a crude oil-polluted soil sample from Geleky, Assam, India. Multiple genes potentially involved in crude oil degradation were identified. PMID:23405324

  8. Antibiotic Susceptibilities of Pseudomonas aeruginosa Isolates Derived from Patients with Cystic Fibrosis under Aerobic, Anaerobic, and Biofilm Conditions

    PubMed Central

    Hill, Dominic; Rose, Barbara; Pajkos, Aniko; Robinson, Michael; Bye, Peter; Bell, Scott; Elkins, Mark; Thompson, Barbara; MacLeod, Colin; Aaron, Shawn D.; Harbour, Colin

    2005-01-01

    Recent studies have determined that Pseudomonas aeruginosa can live in a biofilm mode within hypoxic mucus in the airways of patients with cystic fibrosis (CF). P. aeruginosa grown under anaerobic and biofilm conditions may better approximate in vivo growth conditions in the CF airways, and combination antibiotic susceptibility testing of anaerobically and biofilm-grown isolates may be more relevant than traditional susceptibility testing under planktonic aerobic conditions. We tested 16 multidrug-resistant isolates of P. aeruginosa derived from CF patients using multiple combination bactericidal testing to compare the efficacies of double and triple antibiotic combinations against the isolates grown under traditional aerobic planktonic conditions, in planktonic anaerobic conditions, and in biofilm mode. Both anaerobically grown and biofilm-grown bacteria were significantly less susceptible (P < 0.01) to single and combination antibiotics than corresponding aerobic planktonically grown isolates. Furthermore, the antibiotic combinations that were bactericidal under anaerobic conditions were often different from those that were bactericidal against the same organisms grown as biofilms. The most effective combinations under all conditions were colistin (tested at concentrations suitable for nebulization) either alone or in combination with tobramycin (10 μg ml−1), followed by meropenem combined with tobramycin or ciprofloxacin. The findings of this study illustrate that antibiotic sensitivities are dependent on culture conditions and highlight the complexities of choosing appropriate combination therapy for multidrug-resistant P. aeruginosa in the CF lung. PMID:16207967

  9. Draft Genome Sequence of Pseudomonas aeruginosa Strain Hex1T Isolated from Soils Contaminated with Used Lubricating Oil in Argentina

    PubMed Central

    Luján, Adela M.; Feliziani, Sofía

    2017-01-01

    ABSTRACT Pseudomonas aeruginosa Hex1T was isolated from soils contaminated with used lubricating oil from a garage in Córdoba, Argentina. This strain is capable of utilizing this pollutant as the sole carbon and energy source. Here, we present the 6.9-Mb draft genome sequence of Hex1T, which contains many heavy metal-resistance genes. PMID:28082504

  10. Carbapenem inactivation: a very affordable and highly specific method for phenotypic detection of carbapenemase-producing Pseudomonas aeruginosa isolates compared with other methods.

    PubMed

    Akhi, Mohammad Taghi; Khalili, Younes; Ghotaslou, Reza; Kafil, Hossein Samadi; Yousefi, Saber; Nagili, Behroz; Goli, Hamid Reza

    2016-07-22

    This investigation was undertaken to compare phenotypic and molecular methods for detection of carbapenemase-producing Pseudomonas aeruginosa. A total of 245 non-duplicated isolates of P. aeruginosa were collected from hospitalized patients. Disc diffusion method was used to identify carbapenem-resistant bacteria. Three phenotypic methods, including Modified Hodge Test (MHT), Modified Carba NP (MCNP) test and Carbapenem Inactivation Method (CIM) were used for investigation of carbapenemase production. In addition, polymerase chain reaction (PCR) was used to detect carbapenemase encoding genes. Of 245 P. aeruginosa isolates investigated, 121 isolates were carbapenem-resistant. Among carbapenem-resistant isolates, 40, 39 and 35 isolates exhibited positive results using MHT, MCNP test and CIM, respectively. PCR indicated the presence of carbapenemase genes in 35 of carbapenem-resistant isolates. MHT showed low sensitivity and specificity for carbapenemase detection among P. aeruginosa isolates in comparison to PCR. CIM was most affordable and highly specific than MCNP test compared with the molecular method.

  11. VIM-1, VIM-2, and GES-5 Carbapenemases Among Pseudomonas aeruginosa Isolates at a Tertiary Hospital in Istanbul, Turkey.

    PubMed

    Malkoçoğlu, Gülşah; Aktaş, Elif; Bayraktar, Banu; Otlu, Bariş; Bulut, Mehmet Emin

    2017-04-01

    Worldwide increase in carbapenem resistance and transferable carbapenemases are significant challenges in treatment of Pseudomonas aeruginosa infections. In this study, investigation of carbapenemase production in carbapenem-resistant P. aeruginosa isolates recovered from clinical specimens in a tertiary hospital was aimed. A total of 84 carbapenem-resistant P. aeruginosa isolates were examined. "Carbapenem inactivation method" (CIM) was used for phenotypic detection of carbapenemase production. The existence of blaKPC, blaNDM, blaIMP, blaVIM, blaOXA-48, and blaGES genes was investigated by polymerase chain reaction (PCR). Subtypes of the detected genes were identified by sequence analysis. Arbitrarily primed PCR (AP-PCR) was performed to evaluate the clonal relationship among the isolates. The presence of high-risk clones in carbapenemase producers was investigated by Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). Three isolates (3.5%) were identified as carbapenemase producers by CIM tests, while PCR tests demonstrated three isolates carrying carbapenemase genes as well. blaVIM gene was found in two isolates and blaGES gene was found in one isolate. Sequence analysis demonstrated that the carbapenemases were VIM-1, VIM-2, and GES-5. AP-PCR yielded high clonal diversity among the isolates. According to MALDI-TOF MS analysis, none of the carbapenemase-producing strains belonged to the high-risk clones. In conclusion, the presence of VIM-1, VIM-2, and GES-5 type carbapenemases in P. aeruginosa isolates was demonstrated for the first time in our hospital, GES-5 being reported for the second time in Turkey. Our results will lead strategies for controlling the spread of carbapenemases and contribute to epidemiological data from Turkey.

  12. Growing Menace of Antibacterial Resistance in Clinical Isolates of Pseudomonas aeruginosa in Nepal: An Insight of Beta-Lactamase Production

    PubMed Central

    Dhital, Rabindra; Puri, Ram; Chaudhary, Niraj; Khatiwada, Suresh

    2016-01-01

    Introduction. Pseudomonas aeruginosa is the most frequently isolated organism as it acts as the opportunistic pathogen and can cause infections in immunosuppressed patients. The production of different types of beta-lactamases renders this organism resistant to many commonly used antimicrobials. Therefore, the aim of this study was to document the antibiotic resistance rate in Pseudomonas aeruginosa isolated from different clinical specimens. Methods. Pseudomonas aeruginosa recovered was identified by standard microbiological methods. Antibiotic susceptibility testing was performed by modified Kirby-Bauer disc diffusion method following Clinical and Laboratory Standard Institute (CLSI) guidelines and all the suspected isolates were tested for the production of ESBLs, MBLs, and AmpC. Results. Out of total (178) isolates, 83.1% were recovered from the inpatient department (IPD). Majority of the isolates mediated resistance towards the beta-lactam antibiotics, while nearly half of the isolates were resistant to ciprofloxacin. Most of the aminoglycosides used showed resistance rate up to 75% but amikacin proved to be better option. No resistance to polymyxin was observed. ESBLs, MBLs, and AmpC mediated resistance was seen in 33.1%, 30.9%, and 15.7% isolates, respectively. Conclusions. Antibiotic resistance rate and beta-lactamase mediated resistance were high. Thus, regular surveillance of drug resistance is of utmost importance. PMID:27642599

  13. Isolated Pseudomonas aeruginosa strain VIH2 and antagonistic properties against Ralstonia solanacearum.

    PubMed

    Ge, Xincheng; Wei, Wei; Li, Gen; Sun, Mingming; Li, Huixin; Wu, Jun; Hu, Feng

    2017-10-01

    The aim of this study was to isolates with antagonist activity against R. solanacearum. Thirty-two bacterial isolates were obtained from samples, and they were screened for potential antagonistic activity against R. Solanacearum. Using the agar spot method, ten out of the 21 tested bacteria showed antilisterial activity. VIH2 had the highest inhibitory effect on the growth of R. Solanacearum. Based on 16S rDNA and Biolog test analysis, the strain VIH2 was identified as Pseudomonas aeruginosa. Single-factor and Response Surface Methodology experiments were used to optimize the culture medium and conditions. This study was to explore whether the hemolysin-co-regulated protein secretion island I (HSI-I)-encoded type VI secretion system (T6SS) in Pseudomonas can be used as a biological control approach against Ralstonia solanacearum under field conditions. Bacterial competition assay showed that the HSI-I type T6SS of strain VIH2 exhibited dramatic antibacterial killing activity against R. solanacearum. The HSI-I T6SS of P. aeruginosa was regulated by the ppKA gene. We disrupted the gene ppKA in VIH2 by a single crossover to yield the VIH2 (ΔppKA) mutant. The antagonism of VIH2 was significantly decreased by ppKA gene disruption. In conclusion, our data supported the idea that HSI-I T6SS plays a crucial role in the antagonistic action of strain VIH2 against R. solanacearum. This alternative approach for antagonism against R. solanacearum might help develop attenuated strains of engineered bacteria for biological control. Copyright © 2017. Published by Elsevier Ltd.

  14. Isolation and characterization of mutants defective in the cyanide-insensitive respiratory pathway of Pseudomonas aeruginosa.

    PubMed

    Cunningham, L; Williams, H D

    1995-01-01

    The branched respiratory chain of Pseudomonas aeruginosa contains at least two terminal oxidases which are active under normal physiological conditions. One of these, cytochrome co, is a cytochrome c oxidase which is completely inhibited by concentrations of the respiratory inhibitor potassium cyanide as low as 100 microM. The second oxidase, the cyanide-insensitive oxidase, is resistant to cyanide concentrations in excess of 1 mM as well as to sodium azide. In this work, we describe the isolation and characterization of a mutant of P. aeruginosa defective in cyanide-insensitive respiration. This insertion mutant was isolated with mini-D171 (a replication-defective derivative of the P. aeruginosa phage D3112) as a mutagen and by screening the resulting tetracycline-resistant transductants for the loss of ability to grow in the presence of 1 mM sodium azide. Polarographic studies on the NADH-mediated respiration rate of the mutant indicated an approximate 50% loss of activity, and titration of this activity against increasing cyanide concentrations gave a monophasic curve clearly showing the complete loss of cyanide-insensitive respiration. The mutated gene for a mutant affected in the cyanide-insensitive, oxidase-terminated respiratory pathway has been designated cio. We have complemented the azide-sensitive phenotype of this mutant with a wild-type copy of the gene by in vivo cloning with another mini-D element, mini-D386, carried on plasmid pADD386. The complemented cio mutant regained the ability to grow on medium containing 1 mM azide, titration of its NADH oxidase activity with cyanide gave a biphasic curve similar to that of the wild-type organism, and the respiration rate returned to normal levels. Spectral analysis of the cytochrome contents of the membranes of the wild type, the cio mutant, and the complemented mutant suggests that the cio mutant is not defective in any membrane-bound cytochromes and that the complementing gene does not encode a heme

  15. In Vitro Activity of Fosfomycin against a Collection of Clinical Pseudomonas aeruginosa Isolates from 16 Spanish Hospitals: Establishing the Validity of Standard Broth Microdilution as Susceptibility Testing Method

    PubMed Central

    Díez-Aguilar, María; del Campo, Rosa; García-Castillo, María; Zamora, Javier; Cantón, Rafael

    2013-01-01

    The broth microdilution method for fosfomycin and Pseudomonas aeruginosa was assessed and compared with the approved agar dilution method in 206 genetically unrelated P. aeruginosa clinical isolates. Essential agreement between the two methods was 84%, and categorical agreement was 89.3%. Additionally, Etest and disk diffusion assays were performed. Results validate broth microdilution as a reliable susceptibility testing method for fosfomycin against P. aeruginosa. Conversely, unacceptable concordance was established between Etest and disk diffusion results with agar dilution results. PMID:23939889

  16. Evaluate the Relationship Between Class 1 Integrons and Drug Resistance Genes in Clinical Isolates of Pseudomonas aeruginosa

    PubMed Central

    Hosseini, Seyed Mohammad Javad; Naeini, Niloofar Shoaee; Khaledi, Azad; Daymad, Seyede Fatemeh; Esmaeili, Davoud

    2016-01-01

    Background: The prevalence of resistant Pseudomonas aeruginosa isolates is increasing and it is considered as one of the major public health concerns in the world. The association between integrons and drug resistance has been proven and evidences suggest that integrons are coding and responsible for dissemination of antibiotic resistance among P. aeruginosa isolates. Objective: This study is aimed to evaluate the relationship between class 1 integrons and drug resistance genes in clinical isolates of P. aeruginosa from burn patients. Methods: 100 isolates of P. aeruginosa were collected from burn patients hospitalized in the skin ward of Shahid Motahari hospital and susceptibility testing was performed by disk diffusion method (Kirby-Bauer). Then DNA was extracted and PCR technique was performed for the detection of class 1 integrons and drug resistance genes. Then data was analyzed using SPSS software. Results: The most effective antibiotic was polymyxin B with sensitivity 100%, and the most resistance was observed to the ciprofloxacin (93%) and amikacin (67%), respectively. The maximum and lowest frequencies of drug resistance genes belonged to the aac (6 ') - 1, VEB-1 with prevalence rate 93% and 10%, respectively. The statistical Chi-square test did not find any significant correlation between class 1 integrons and drug resistance genes (p˃ 0.05). Conclusion: Although no significant correlation between class 1 integrons and drug resistance was observed, but the resistance rate to antibiotics tested among P. aeruginosa isolates was high. So, surveillance, optimization and strict consideration of antimicrobial use and control of infection are necessary. PMID:28077975

  17. Molecular Detection of the Virulent ExoU Genotype of Pseudomonas aeruginosa Isolated from Infected Surgical Incisions.

    PubMed

    Hassuna, Noha A

    2016-10-01

    Pseudomonas aeruginosa is one of the major pathogens responsible for hospital-acquired infections, which harbor a wide array of virulence factors. The main aim of this study was to determine the frequency of the virulent ExoU genotype in relation to the ExoS genotype among isolated P. aeruginosa from infected surgical incisions, followed by phylogenetic analysis. A total of 66 P. aeruginosa isolates were identified by cultural and biochemical characteristics. All isolates were tested for antimicrobial susceptibility against the following antimicrobial agents: imipenem, amikacin, gentamicin, amoxycillin, cefotaxime, cefepime, and levofloxacin. Molecular detection of the ExoS and ExoU as well as two other virulence genes was done by polymerase chain reaction (PCR). Sequencing of ExoU gene and phylogenetic analysis was performed. Approximately 81% of the isolated P. aeruginosa were multi-drug resistant. The ExoS genotype was more prevalent (63%) among the isolates than the ExoU genotype (18%), with 9% of the isolates possessing both toxins. LasB and AprA were detected in 63.6% and 27.2% of the isolates, respectively. An association was observed between the number of virulence genes and the presence of multi-drug resistance. All the ExoU were multi-drug resistant (MDR), whereas 71% of the ExoS were MDR. Phylogenetic analysis of ExoU gene showed a 99% similarity with four different strains. Despite the greater frequency of the ExoS genotype, the presence of the virulent MDR ExoU genotype isolates from surgical site infections is an alarming sign requiring further intervention and investigations.

  18. Biofilm formation, antibiotic susceptibility and RAPD genotypes in Pseudomonas aeruginosa clinical strains isolated from single centre intensive care unit patients.

    PubMed

    Vaněrková, Martina; Mališová, Barbora; Kotásková, Iva; Holá, Veronika; Růžička, Filip; Freiberger, Tomáš

    2017-04-01

    The aim of this study was to analyse genotypes, antimicrobial susceptibility patterns and serotypes in Pseudomonas aeruginosa clinical strains, including the clonal dissemination of particular strains throughout various intensive care units in one medical centre. Using random amplified polymorphic DNA (RAPD-PCR) and P. aeruginosa antisera, 22 different genotypes and 8 serotypes were defined among 103 isolates from 48 patients. No direct association between P. aeruginosa strain genotypes and serotypes was observed. RAPD typing in strains with the same serotype revealed different genotypes and, on the contrary, most strains with a different serotype displayed the same amplification pattern. The resulting banding patterns showed a high degree of genetic heterogeneity among all isolates from the patients examined, suggesting a non-clonal relationship between isolates from these patients. A higher degree of antibiotic resistance and stronger biofilm production in common genotypes compared to rare ones and genetic homogeneity of the most resistant strains indicated the role of antibiotic pressure in acquiring resistant and more virulent strains in our hospital. In conclusion, genetic characterisation of P. aeruginosa strains using RAPD method was shown to be more accurate in epidemiological analyses than phenotyping.

  19. Biosurfactant production by Pseudomonas aeruginosa DSVP20 isolated from petroleum hydrocarbon-contaminated soil and its physicochemical characterization.

    PubMed

    Sharma, Deepak; Ansari, Mohammad Javed; Al-Ghamdi, Ahmad; Adgaba, Nuru; Khan, Khalid Ali; Pruthi, Vikas; Al-Waili, Noori

    2015-11-01

    Among 348 microbial strains isolated from petroleum hydrocarbon-contaminated soil, five were selected for their ability to produce biosurfactant based on battery of screening assay including hemolytic activity, surface tension reduction, drop collapse assay, emulsification activity, and cell surface hydrophobicity studies. Of these, bacterial isolate DSVP20 was identified as Pseudomonas aeruginosa (NCBI GenBank accession no. GQ865644) based on biochemical characterization and the 16S rDNA analysis, and it was found to be a potential candidate for biosurfactant production. Maximum biosurfactant production recorded by P. aeruginosa DSVP20 was 6.7 g/l after 72 h at 150 rpm and at a temperature of 30 °C. Chromatographic analysis and high-performance liquid chromatography-mass spectrometry (HPLC-MS) revealed that it was a glycolipid in nature which was further confirmed by nuclear magnetic resonance (NMR) spectroscopy. Bioremediation studies using purified biosurfactant showed that P. aeruginosa DSVP20 has the ability to degrade eicosane (97%), pristane (75%), and fluoranthene (47%) when studied at different time intervals for a total of 7 days. The results of this study showed that the P. aeruginosa DSVP20 and/or biosurfactant produced by this isolate have the potential role in bioremediation of petroleum hydrocarbon-contaminated soil.

  20. Characterization of glycolipid biosurfactant from Pseudomonas aeruginosa CPCL isolated from petroleum-contaminated soil.

    PubMed

    Arutchelvi, J; Doble, M

    2010-07-01

    To isolate and characterize the biosurfactant-producing micro-organism from petroleum-contaminated soil as well as to determine the biochemical properties of the biosurfactant. A novel rhamnolipid-producing Pseudomonas aeruginosa (GenBank accession number GQ241355) strain was isolated from a petroleum-contaminated soil. Surface active compound was separated by solvent extraction of the acidified culture supernatant. The extract was able to reduce the surface tension of water from 72 to 44 mN m(-1) at a critical micelle concentration of 11.27 +/- 1.85 mg l(-1). It showed better activity (based on microdilution method) against Gram-positive (or= 125 mg ml(-1)) with mild toxicity (HC(50)- 38 +/- 8.22 microg ml(-1)) to red blood cells. Fourier transform infrared spectroscopy revealed the presence of aliphatic chain, hydroxyl groups, ester and glycosidic bonds. Presence of nineteen rhamnolipid homologues with variation in chain length and saturation was revealed from liquid chromatography coupled to mass spectrometry with electrospray ionization. The results indicate that the isolated biosurfactant has a novel combination of rhamnolipid congeners with unique properties. This study provides a biosurfactant, which can be used as a biocontrol agent against phytopathogens (Fusarium proliferatum NCIM 1105 and Aspergillus niger NCIM 596) and exploited for biomedical applications.

  1. Determination of Acquired Resistance Profiles of Pseudomonas aeruginosa Isolates and Characterization of an Effective Bacteriocin-Like Inhibitory Substance (BLIS) Against These Isolates

    PubMed Central

    Shokri, Dariush; Rabbani Khorasgani, Mohammad; Zaghian, Saeideh; Fatemi, Seyed Masih; Mohkam, Milad; Ghasemi, Younes; Taheri-Kafrani, Asghar

    2016-01-01

    Background The emergence of pan-drug resistant strains (PDR) of Pseudomonas aeruginosa has led to renewed efforts to identify alternative agents, such as bacteriocins and bacteriocin-like inhibitory substances (BLISs). Objectives The aims of this study were to determine the acquired resistance profiles of multidrug-resistant (MDR), extensively drug-resistant (XDR), and PDR P. aeruginosa isolates based on the revised definitions of the CDC and ECDC and to screen and characterize effective BLISs against these isolates. Patients and Materials In a cross-sectional study, 96 P. aeruginosa strains were isolated during a 12-month period. The resistance profiles of these isolates were determined as MDR, XDR, and PDR, and the data were analyzed using WHONET5.6 software. A BLIS against the P. aeruginosa strains was characterized based on its physicochemical properties, size, growth curves, and production profiles. Results Among the 96 isolates of P. aeruginosa, 2 (2.1%), 94 (97.9%), and 63 (65.6%) were non-MDR, MDR, and XDR, respectively, and 1 (1.1%) was PDR. The most effective antibiotics against these isolates were polymyxins and fosfomycin. A BLIS isolated from the P. aeruginosa DSH22 strain had potent activity against 92 (95.8%) of the 96 isolates. The BLIS was heat stable, (up to 100°C for 10 min), UV stable, and active within a pH range of 3 - 9. The activity of BLIS disappeared when treated with trypsin, proteinase K, and pepsin, indicating its proteinous nature. Based on its size (25 kDa), the BLIS may belong to the large colicin-like bacteriocin family. BLIS production started in the midexponential phase of growth, and the maximum level (2700 AU/mL) occurred in the late-stationary phase after 25 hours of incubation at 30°C. Conclusions This BLIS with broad-spectrum activity may be a potential agent for the treatment or control of drug-resistant strains of P. aeruginosa infection. PMID:27800131

  2. A comparison of two informative SNP-based strategies for typing Pseudomonas aeruginosa isolates from patients with cystic fibrosis

    PubMed Central

    2014-01-01

    Background Molecular typing is integral for identifying Pseudomonas aeruginosa strains that may be shared between patients with cystic fibrosis (CF). We conducted a side-by-side comparison of two P. aeruginosa genotyping methods utilising informative-single nucleotide polymorphism (SNP) methods; one targeting 10 P. aeruginosa SNPs and using real-time polymerase chain reaction technology (HRM10SNP) and the other targeting 20 SNPs and based on the Sequenom MassARRAY platform (iPLEX20SNP). Methods An in-silico analysis of the 20 SNPs used for the iPLEX20SNP method was initially conducted using sequence type (ST) data on the P. aeruginosa PubMLST website. A total of 506 clinical isolates collected from patients attending 11 CF centres throughout Australia were then tested by both the HRM10SNP and iPLEX20SNP assays. Type-ability and discriminatory power of the methods, as well as their ability to identify commonly shared P. aeruginosa strains, were compared. Results The in-silico analyses showed that the 1401 STs available on the PubMLST website could be divided into 927 different 20-SNP profiles (D-value = 0.999), and that most STs of national or international importance in CF could be distinguished either individually or as belonging to closely related single- or double-locus variant groups. When applied to the 506 clinical isolates, the iPLEX20SNP provided better discrimination over the HRM10SNP method with 147 different 20-SNP and 92 different 10-SNP profiles observed, respectively. For detecting the three most commonly shared Australian P. aeruginosa strains AUST-01, AUST-02 and AUST-06, the two methods were in agreement for 80/81 (98.8%), 48/49 (97.8%) and 11/12 (91.7%) isolates, respectively. Conclusions The iPLEX20SNP is a superior new method for broader SNP-based MLST-style investigations of P. aeruginosa. However, because of convenience and availability, the HRM10SNP method remains better suited for clinical microbiology laboratories that only utilise real

  3. Effects of fertilizer-urea on growth, photosynthetic activity and microcystins production of Microcystis aeruginosa isolated from Dianchi Lake.

    PubMed

    Huang, Wenmin; Bi, Yonghong; Hu, Zhengyu

    2014-05-01

    Urea is the most frequently applied nitrogen (N) fertilizer in agriculture, while its loss is assumed triggering algal blooms in adjacent water bodies. In this context the present study assessed the growth, photosynthetic activity as well as toxin production of Microcystis aeruginosa at different urea concentrations (0.125, 1.25, 12.5, 250 and 2,500 mg/L) using BG11 (containing 250 mg/L NO3(-)-N) as control. The results showed for all endpoints that M. aeruginosa is capable of using urea as N source: the two highest urea treatments delivered comparable values like the control. Low urea concentrations (0.125 and 1.25 mg/L), which were comparable to environmental urea levels, did not sustainably promote the growth, photosynthesis and toxin production of the test species. While, in certain microenvironments urea might potentially reach the concentrations that may affect M. aeruginosa.

  4. Effects of glyphosate at environmentally relevant concentrations on the growth of and microcystin production by Microcystis aeruginosa.

    PubMed

    Zhang, Quan; Zhou, Hang; Li, Zhe; Zhu, Jianqiang; Zhou, Cong; Zhao, Meirong

    2016-11-01

    The use of glyphosate, which is a well-known sterilant herbicide, has been growing rapidly because the area under the cultivation of genetically modified crops that are tolerant to this herbicide has increased. Glyphosate can enter into aquatic systems through many different ways. However, information on the potential risks of glyphosate at environmentally relevant levels to aquatic systems is still limited. In this study, we selected the cyanobacterium Microcystis aeruginosa FACHB-905 (M. aeruginosa) as a model organism to evaluate the effects of glyphosate at environmentally relevant concentrations on the former's growth and microcystin (MC) production. Our results show that low levels of glyphosate stimulate the growth of M. aeruginosa. Subsequently, there was significant increase in the total MC-LR and intracellular MC-LR, but not in extracellular MC-LR, after exposure to 0.1-2 mg/L of glyphosate. The increase in total MC-LR is mainly due to the effects of glyphosate on the cell density of M. aeruginosa. The data provided here show that low level of glyphosate in a water body is a potential environmental risk factor that stimulates the growth and enhances MC production in M. aeruginosa, which should arouse great concern.

  5. Isolation and identification of a novel, lipase-producing bacterium, Pseudomnas aeruginosa KM110

    PubMed Central

    Mobarak-Qamsari, E; Kasra-Kermanshahi, R; Moosavi-nejad, Z

    2011-01-01

    Background and Objectives Lipases are particularly important due to the fact that they specifically hydrolyze acyl glycerol, oils and greases, which is of great interest for different industrial applications. Materialst and Methods In this study, several lipase-producing bacteria were isolated from wastewater of an oil processing plant. The strain possessing the highest lipase activity was identified both biochemically and sequencing of 16S rRNA gene. Then we increase lipase activity by improving conditions of production medium. Also, lipase from this strain was preliminarily characterized for use in industrial application. Results The 16S rRNA sequensing revealed it as a new strain of Pseudomonas aeruginosa and the type strain was KM110. An overall 3-fold enhanced lipase production (0.76 U mL−1) was achieved after improving conditions of production medium. The olive oil and peptone was found to be the most suitable substrate for maximum enzyme production. Also the enzyme exhibited maximum lipolytic activity at 45°C where it was also stably maintained. At pH 8.0, the lipase had the highest stability but no activity. It was active over a pH range of 7.0–10.0. The lipase activity was inhibited by Zn2+ & Cu2+ (32 and 27%, respectively) at 1mM. The enzyme lost 29% of its initial activity in 1.0% SDS concentration, whereas, Triton X-100, Tween-80 & DMSO did not significantly inhibit lipase activity. Conclusions Based on the findings of present study, lipase of P. aeruginosa KM110 is a potential alkaline lipase and a candidate for industrial applications such as detergent, leather and fine chemical industries. PMID:22347589

  6. Single step biotransformation of corn oil phytosterols to boldenone by a newly isolated Pseudomonas aeruginosa.

    PubMed

    Eisa, Mohamed; El-Refai, Heba; Amin, Magdy

    2016-09-01

    A new potent Pseudomonas aeruginosa isolate capable for biotransformation of corn oil phytosterol (PS) to 4-androstene-3, 17-dione (AD), testosterone (T) and boldenone (BOL) was identified by phenotypic analysis and 16S rRNA gene sequencing. Sequential statistical strategy was used to optimize the biotransformation process mainly concerning BOL using Factorial design and response surface methodology (RSM). The production of BOL in single step microbial biotransformation from corn oil phytosterols by P. aeruginosa was not previously reported. Results showed that the pH concentration of the medium, (NH4)2SO4 and KH2PO4 were the most significant factors affecting BOL production. By analyzing the statistical model of three-dimensional surface plot, BOL production increased from 36.8% to 42.4% after the first step of optimization, and the overall biotransformation increased to 51.9%. After applying the second step of the sequential statistical strategy BOL production increased to 53.6%, and the overall biotransformation increased to 91.9% using the following optimized medium composition (g/l distilled water) (NH4)2SO4, 2; KH2PO4, 4; Na2HPO4. 1; MgSO4·7H2O, 0.3; NaCl, 0.1; CaCl2·2H2O, 0.1; FeSO4·7H2O, 0.001; ammonium acetate 0.001; Tween 80, 0.05%; corn oil 0.5%; 8-hydroxyquinoline 0.016; pH 8; 200 rpm agitation speed and incubation time 36 h at 30 °C. Validation experiments proved the adequacy and accuracy of model, and the results showed the predicted value agreed well with the experimental values.

  7. Analysis of biofilm production by clinical isolates of Pseudomonas aeruginosa from patients with ventilator-associated pneumonia.

    PubMed

    Lima, Jailton Lobo da Costa; Alves, Lilian Rodrigues; Paz, Jussyêgles Niedja Pereira da; Rabelo, Marcelle Aquino; Maciel, Maria Amélia Vieira; Morais, Marcia Maria Camargo de

    2017-09-04

    To phenotypically evaluate biofilm production by Pseudomonas aeruginosa clinically isolated from patients with ventilator-associated pneumonia. Twenty clinical isolates of P. aeruginosa were analyzed, 19 of which were from clinical samples of tracheal aspirate, and one was from a bronchoalveolar lavage sample. The evaluation of the capacity of P. aeruginosa to produce biofilm was verified using two techniques, one qualitative and the other quantitative. The qualitative technique showed that only 15% of the isolates were considered biofilm producers, while the quantitative technique showed that 75% of the isolates were biofilm producers. The biofilm isolates presented the following susceptibility profile: 53.3% were multidrug-resistant, and 46.7% were multidrug-sensitive. The quantitative technique was more effective than the qualitative technique for the detection of biofilm production. For the bacterial population analyzed, biofilm production was independent of the susceptibility profile of the bacteria, demonstrating that the therapeutic failure could be related to biofilm production, as it prevented the destruction of the bacteria present in this structure, causing complications of pneumonia associated with mechanical ventilation, including extrapulmonary infections, and making it difficult to treat the infection.

  8. In vitro antibacterial activity of rifampicin in combination with imipenem, meropenem and doripenem against multidrug-resistant clinical isolates of Pseudomonas aeruginosa.

    PubMed

    Hu, Yi-Fan; Liu, Chang-Pan; Wang, Nai-Yu; Shih, Shou-Chuan

    2016-08-24

    Multidrug-resistant Pseudomonas aeruginosa has emerged as one of the most important healthcare-associated pathogens. Colistin is regarded as the last-resort antibiotic for multidrug-resistant Gram-negative bacteria, but is associated with high rates of acute kidney injury. The aim of this in vitro study is to search for an alternative treatment to colistin for multidrug-resistant P. aeruginosa infections. Multidrug and carbapenem-resistant P. aeruginosa isolates were collected between January 2009 and December 2012 at MacKay Memorial Hospital. Minimal inhibitory concentrations (MICs) were determined for various antibiotic combinations. Carbapenemase-producing genes including bla VIM, other β-lactamase genes and porin mutations were screened by PCR and sequencing. The efficacy of carbapenems (imipenem, meropenem, doripenem) with or without rifampicin was correlated with the type of porin mutation (frameshift mutation, premature stop codon mutation) in multidrug-resistant P. aeruginosa isolates without carbapenemase-producing genes. Of the 71 multidrug-resistant clinical P. aeruginosa isolates, only six harboured the bla VIM gene. Imipenem, meropenem and doripenem were significantly more effective (reduced fold-change of MICs) when combined with rifampicin in bla VIM-negative isolates, especially in isolates with porin frameshift mutation. Imipenem + rifampicin combination has a low MIC against multidrug-resistant P. aeruginosa, especially in isolates with porin frameshift mutation. The imipenem + rifampicin combination may provide an alternative treatment to colistin for multidrug -resistant P. aeruginosa infections, especially for patients with renal insufficiency.

  9. Detection of Pseudomonas aeruginosa from clinical and environmental samples by amplification of the exotoxin A gene using PCR.

    PubMed Central

    Khan, A A; Cerniglia, C E

    1994-01-01

    PCR was used to detect Pseudomonas aeruginosa from water samples by amplifying a 396-bp region of the exotoxin A (ETA) structural gene sequence. The identify of the amplified 396-bp fragment was confirmed by digesting it with PvuI restriction endonuclease, which produced the predicted 246- and 150-bp fragments. Specific primers amplified ETA-positive P. aeruginosa DNA, whereas other species of Pseudomonas and GC-rich bacteria did not yield any 396-bp fragment. The specificity and sensitivity of the assay were 100 and 96%, respectively, which confirms the assay's reliability for diagnostic and epidemiological studies. The assay can detect as few as 5 to 10 cells in a 10-ml water sample or 0.1 pg of P. aeruginosa DNA per reaction mixture (5 microliters) by ethidium bromide staining of an agarose gel. Ten-times-lower concentrations were detected by hybridization with a digoxigenin-labeled oligonucleotide probe internal to the PCR product. With this PCR method, ETA-positive P. aeruginosa was detected in animal cage water samples at a level of 40 cells per ml. This method is rapid and less cumbersome than other diagnostic methods for the identification of P. aeruginosa strains. The method described can be used to detect a low level of P. aeruginosa from environmental and clinical samples without the use of selective media or additional biochemical tests. Images PMID:7986047

  10. Magnesium limitation is an environmental trigger of the Pseudomonas aeruginosa biofilm lifestyle.

    PubMed

    Mulcahy, Heidi; Lewenza, Shawn

    2011-01-01

    Biofilm formation is a conserved strategy for long-term bacterial survival in nature and during infections. Biofilms are multicellular aggregates of cells enmeshed in an extracellular matrix. The RetS, GacS and LadS sensors control the switch from a planktonic to a biofilm mode of growth in Pseudomonas aeruginosa. Here we detail our approach to identify environmental triggers of biofilm formation by investigating environmental conditions that repress expression of the biofilm repressor RetS. Mg(2+) limitation repressed the expression of retS leading to increased aggregation, exopolysaccharide (EPS) production and biofilm formation. Repression of retS expression under Mg(2+) limitation corresponded with induced expression of the GacA-controlled small regulatory RNAs rsmZ and rsmY and the EPS biosynthesis operons pel and psl. We recently demonstrated that extracellular DNA sequesters Mg(2+) cations and activates the cation-sensing PhoPQ two-component system, which leads to increased antimicrobial peptide resistance in biofilms. Here we show that exogenous DNA and EDTA, through their ability to chelate Mg(2+), promoted biofilm formation. The repression of retS in low Mg(2+) was directly controlled by PhoPQ. PhoP also directly controlled expression of rsmZ but not rsmY suggesting that PhoPQ controls the equilibrium of the small regulatory RNAs and thus fine-tunes the expression of genes in the RetS pathway. In summary, Mg(2+) limitation is a biologically relevant environmental condition and the first bonafide environmental signal identified that results in transcriptional repression of retS and promotes P. aeruginosa biofilm formation.

  11. Magnesium Limitation Is an Environmental Trigger of the Pseudomonas aeruginosa Biofilm Lifestyle

    PubMed Central

    Mulcahy, Heidi; Lewenza, Shawn

    2011-01-01

    Biofilm formation is a conserved strategy for long-term bacterial survival in nature and during infections. Biofilms are multicellular aggregates of cells enmeshed in an extracellular matrix. The RetS, GacS and LadS sensors control the switch from a planktonic to a biofilm mode of growth in Pseudomonas aeruginosa. Here we detail our approach to identify environmental triggers of biofilm formation by investigating environmental conditions that repress expression of the biofilm repressor RetS. Mg2+ limitation repressed the expression of retS leading to increased aggregation, exopolysaccharide (EPS) production and biofilm formation. Repression of retS expression under Mg2+ limitation corresponded with induced expression of the GacA-controlled small regulatory RNAs rsmZ and rsmY and the EPS biosynthesis operons pel and psl. We recently demonstrated that extracellular DNA sequesters Mg2+ cations and activates the cation-sensing PhoPQ two-component system, which leads to increased antimicrobial peptide resistance in biofilms. Here we show that exogenous DNA and EDTA, through their ability to chelate Mg2+, promoted biofilm formation. The repression of retS in low Mg2+ was directly controlled by PhoPQ. PhoP also directly controlled expression of rsmZ but not rsmY suggesting that PhoPQ controls the equilibrium of the small regulatory RNAs and thus fine-tunes the expression of genes in the RetS pathway. In summary, Mg2+ limitation is a biologically relevant environmental condition and the first bonafide environmental signal identified that results in transcriptional repression of retS and promotes P. aeruginosa biofilm formation. PMID:21858064

  12. A gacS Deletion in Pseudomonas aeruginosa Cystic Fibrosis Isolate CHA Shapes Its Virulence

    PubMed Central

    Sall, Khady Mayebine; Casabona, Maria Guillermina; Bordi, Christophe; Huber, Philippe; de Bentzmann, Sophie; Attrée, Ina; Elsen, Sylvie

    2014-01-01

    Pseudomonas aeruginosa, a human opportunistic pathogen, is capable of provoking acute and chronic infections that are associated with defined sets of virulence factors. During chronic infections, the bacterium accumulates mutations that silence some and activate other genes. Here we show that the cystic fibrosis isolate CHA exhibits a unique virulence phenotype featuring a mucoid morphology, an active Type III Secretion System (T3SS, hallmark of acute infections), and no Type VI Secretion System (H1-T6SS). This virulence profile is due to a 426 bp deletion in the 3′ end of the gacS gene encoding an essential regulatory protein. The absence of GacS disturbs the Gac/Rsm pathway leading to depletion of the small regulatory RNAs RsmY/RsmZ and, in consequence, to expression of T3SS, while switching off the expression of H1-T6SS and Pel polysaccharides. The CHA isolate also exhibits full ability to swim and twitch, due to active flagellum and Type IVa pili. Thus, unlike the classical scheme of balance between virulence factors, clinical strains may adapt to a local niche by expressing both alginate exopolysaccharide, a hallmark of membrane stress that protects from antibiotic action, host defences and phagocytosis, and efficient T3S machinery that is considered as an aggressive virulence factor. PMID:24780952

  13. Centrifugal partition chromatography: A preparative tool for isolation and purification of xylindein from Chlorociboria aeruginosa.

    PubMed

    Boonloed, Anukul; Weber, Genevieve L; Ramzy, Kelly M; Dias, Veronica R; Remcho, Vincent T

    2016-12-23

    A centrifugal partition chromatography (CPC) method was developed for the preparative-scale isolation and purification of xylindein from the wood-staining fungi, Chlorociboria aeruginosa. Xylindein, a blue-green pigment naturally secreted from the hyphae and fruiting bodies of the fungus, has great value in the decorative wood industry and textile coloration. Xylindein has great potential for use as a fluorescent labeling agent as well as in organic semiconductor applications. However, a primary limitation of xylindein is its poor solubility in most common HPLC solvents. Consequently, it is arduous to purify using preparative liquid chromatography or solid-phase extraction (SPE). Support-free, liquid-liquid chromatographic methods, including CPC, where solutes are separated based on their different distribution coefficients (KD) between two immiscible solvent systems, are promising alternatives for the purification of the compound on a preparative scale. In this work, a new biphasic solvent system suitable for CPC separation of xylindein was developed. Various groups of solvents were assessed for their suitability as xylindein extractants. A new solvent system suitable for CPC separation of xylindein, composed of heptane/THF/MEK/acetonitrile/acetic acid/water, was developed. This solvent system yielded a KD value for xylindein of 1.54±0.04, as determined by HPLC (n=3). The compositions of the upper phase and lower phase of the solvent system were determined by Heteronuclear Single Quantum Correlation (HSQC) NMR and proton NMR. A CPC system, equipped with a fraction collector, was used for the isolation of xylindein from crude extracts. The xylindein fractions isolated by the CPC were then analyzed using HPLC and presented as a fractogram. Based on the CPC fractogram, the purified xylindein fractions were achieved after 30min CPC separation time, yielding 71% extraction efficiency. The developed CPC method allowed for isolation of this naturally sourced xylindein

  14. 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.

  15. Detection of Multidrug Resistant (MDR) and Extremely Drug Resistant (XDR) P. Aeruginosa Isolated from Patients in Tehran, Iran

    PubMed Central

    Saderi, Horieh; Owlia, Parviz

    2015-01-01

    Background: This study was done to detect multidrug resistant (MDR) and extremely drug resistant (XDR) of Pseudomonas aeruginosa among strains isolated from patients in Tehran, Iran, due to importance of these phenotypes in treatment of human infections. Methods: Eighty eight P. aeruginosa were isolated from patients in Tehran, Iran, and identified by routine methods and PCR for oprL gene. Their antimicrobial susceptibility to 16 antimicrobial agents from 7 antimicrobial categories (aminoglycosides, carbapenems, cephalosporins, fluoroquinolones, penicillins/ß-lactamase inhibitors, monobactams, polymyxins) were determined by disk diffusion method, according to recommendation of Clinical and Laboratory Standards Institute. Characterization of P. aeruginosa isolates as MDR and XDR was done according to standardized international terminology presented by European Centre for Disease Prevention and Control as well as the Centers for Disease Control and Prevention in 2011. MDR was defined as acquired non-susceptibility to at least one agent in ≥3 antimicrobial categories and XDR was defined as non-susceptibility to at least one agent in ≥6 antimicrobial categories. Results: The rates of susceptibility to antimicrobials were as follows: gentamicin 27.3%, tobramycin 54.5%, amikacin 56.8%, netilmicin 36.4%, imipenem 55.7%, meropenem 55.7%, doripenem 60.2%, ceftazidime 63.6%, cefepime 56.8%, ciprofloxacin 59.1%, levofloxacin 60.2%, ticarcillin-clavulanic acid 37.5%, piperacillin-tazobactam 63.6%, aztreonam 43.2%, colistin 90.9%, polymyxin 95.5%. Altogether, 48 (54.5%) and 29 (33%) isolates were characterized as MDR and XDR, respectively. Discussion: The high frequency of antibiotic resistance in clinical isolates of P. aeruginosa in Iran makes epidemiological surveillance of susceptibility of this bacterium more essential for the best selection of empirical antibiotics. PMID:26351496

  16. Screening & profiling of quorum sensing signal molecules in Pseudomonas aeruginosa isolates from catheterized urinary tract infection patients

    PubMed Central

    Kumar, Ravi; Chhibber, Sanjay; Gupta, Varsha; Harjai, Kusum

    2011-01-01

    Background & objectives: Catheter associated urinary tract infections are the second most common nosocomial infections and Pseudomonas aeruginosa is the third most common organism responsible for these infections. In this study P. aeruginosa isolates from catheterized urinary tract infection patients were screened and profiled for the presence of different type of quorum sensing (QS) signal molecules. Methods: Screening and quantitation of AHLs was done by using cross feeding assay and by determining β-galactosidase activity respectively using Escherichia coli MG4 as reporter strain. Further, AHL profiles were determined by separating AHLs on TLC coupled with their detection using Chromobacterium violaceum CV026 and Agrobacterium tumifaciens A136 biosensor strains. Results: All uroisolates from catheterized patients having urinary tract infections were found to be producers of QS signal molecules. There were differences in amounts and type of AHL produced amongst uroisolates of P. aeruginosa. Several AHLs belonging to C4-HSL, C6-HSL, oxo-C6-HSL, C8-HSL, C10-HSL and C12-HSL were determined in these strains. Interpretation & conclusions: Simultaneous use of more than one reporter strain and assay method proved useful in determining the AHLs profile in uroisolates of P. aeruginosa. Observed differences in the amounts and types of AHLs may reflect differences in virulence potential of P. aeruginosa to cause UTIs which can be further confirmed by employing animal model system. The present study speculates that production of QS signal molecules may act as a new virulence marker of P. aeruginosa responsible for causing catheter associated UTIs and can be considered as futuristic potential drug targets towards treatment of UTIs. PMID:21911974

  17. Screening & profiling of quorum sensing signal molecules in Pseudomonas aeruginosa isolates from catheterized urinary tract infection patients.

    PubMed

    Kumar, Ravi; Chhibber, Sanjay; Gupta, Varsha; Harjai, Kusum

    2011-08-01

    Catheter associated urinary tract infections are the second most common nosocomial infections and Pseudomonas aeruginosa is the third most common organism responsible for these infections. In this study P. aeruginosa isolates from catheterized urinary tract infection patients were screened and profiled for the presence of different type of quorum sensing (QS) signal molecules. Screening and quantitation of AHLs was done by using cross feeding assay and by determining β-galactosidase activity respectively using Escherichia coli MG4 as reporter strain. Further, AHL profiles were determined by separating AHLs on TLC coupled with their detection using Chromobacterium violaceum CV026 and Agrobacterium tumifaciens A136 biosensor strains. All uroisolates from catheterized patients having urinary tract infections were found to be producers of QS signal molecules. There were differences in amounts and type of AHL produced amongst uroisolates of P. aeruginosa. Several AHLs belonging to C4-HSL, C6-HSL, oxo-C6-HSL, C8-HSL, C10-HSL and C12-HSL were determined in these strains. Simultaneous use of more than one reporter strain and assay method proved useful in determining the AHLs profile in uroisolates of P. aeruginosa. Observed differences in the amounts and types of AHLs may reflect differences in virulence potential of P. aeruginosa to cause UTIs which can be further confirmed by employing animal model system. The present study speculates that production of QS signal molecules may act as a new virulence marker of P. aeruginosa responsible for causing catheter associated UTIs and can be considered as futuristic potential drug targets towards treatment of UTIs.

  18. [Morphologic, cultural, and biochemical properties of cultures of Pseudomonas aeruginosa isolated from patients, animals, and the environment].

    PubMed

    Litovchenko, P P; Zabotina, I V

    1981-05-01

    The properties of 279 Ps. aeruginosa strains were studied in 70 tests. The use of a synthetic peptone-free mineral medium for the determination of sugar oxidation was shown to have advantages over the use of liquid Giess' media. Ps. aeruginosa cultures isolated from human patients, animals, soil and water were characterized by a number of common signs, irrespective of their origin. The strains isolated from human patients were resistant practically to all antibiotics widely used in clinical practice; the cultures isolated from soil and water retained their sensitivity to antibiotics; the strains isolated from animals retained sensitivity to some antibiotics. To identify Ps. aeruginosa in practical bacteriological laboratories, the following parameters should be determined: mobility; the character of growth in Levine's and Ploskirev's media; ability to grow at 42 degrees C and 4 degrees C; the fermentation of carbohydrates in Olkenitsky's medium and their oxidation in a mineral medium; indole and hydroxide sulfide production; the methyl red and Voges--Proskauer reaction; the presence of pigments, oxidase, catalase, gelatinase, nitrate reductase and arginine dehydrolase, urease; resistance to antibiotics.

  19. [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.

  20. 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. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

  1. Isolation and characterization of a bacteriophage specific for the lipopolysaccharide of rough derivatives of Pseudomonas aeruginosa strain PAO.

    PubMed Central

    Jarrell, K F; Kropinski, A M

    1981-01-01

    A lipopolysaccharide (LPS)-defective (rough) mutant of Pseudomonas aeruginosa PAO was isolated by selection for resistance to the LPS-specific phage E79. The LPS of this mutant, AK-1012, lacked the O-antigenic side chain-specific amino sugar fucosamine as well as the core-specific sugars glucose and rhamnose. Using this strain, we isolated and characterized a phage, phi PLS27, which is specifically inactivated upon incubation with LPS extracted from rough mutants of P. aeruginosa PAO. phi PLS27 was found to be a Bradley type C phage and was very similar to coliphage T7 in a number of properties, including size, buoyant density, mass, and the number of structural proteins. Images PMID:6787214

  2. Biosurfactant-producing bacterium, Pseudomonas aeruginosa MA01 isolated from spoiled apples: physicochemical and structural characteristics of isolated biosurfactant.

    PubMed

    Abbasi, Habib; Hamedi, Mir Manochehr; Lotfabad, Tayebe Bagheri; Zahiri, Hossein Shahbani; Sharafi, Hakimeh; Masoomi, Fatemeh; Moosavi-Movahedi, Ali Akbar; Ortiz, Antonio; Amanlou, Massoud; Noghabi, Kambiz Akbari

    2012-02-01

    An extensive investigation was conducted to isolate indigenous bacterial strains with outstanding performance for biosurfactant production from different types of spoiled fruits, food-related products and food processing industries. An isolate was selected from 800 by the highest biosurfactant yield in soybean oil medium and it was identified by 16S rRNA and the two most relevant hypervariable regions of this gene; V3 and V6 as Pseudomonas aeruginosa MA01. The isolate was able to produce 12 g/l of a glycolipid-type biosurfactant and generally less efficient to emulsify vegetable oils compared to hydrocarbons and could emulsify corn and coconut oils more than 50%. However, emulsification index (E(24)) of different hydrocarbons including hexane, toluene, xylene, brake oil, kerosene and hexadecane was between 55.8% and 100%. The surface tension of pure water decreased gradually with increasing biosurfactant concentration to 32.5 mNm(-1) with critical micelle concentration (CMC) value of 10.1mg/l. Among all carbon substrates examined, vegetable oils were the most effective on biosurfactant production. Two glycolipid fractions were purified from the biosurfactant crude extracts, and FTIR and ES-MS were used to determine the structure of these compounds. The analysis indicated the presence of three major monorhamnolipid species: R(1)C(10)C(10), R(1)C(10)C(12:1), and R(1)C(10)C(12); as well as another three major dirhamnolipid species: R(2)C(10)C(10), R(2)C(10)C(12:1), and R(2)C(10)C(12). The strain sweep experiment for measuring the linear viscoelastic of biosurfactant showed that typical behavior characteristics of a weak viscoelastic gel, with storage modulus greater than loss modulus at all frequencies examined, both showing some frequency dependence.

  3. Draft Genome Sequence of Pseudomonas aeruginosa Strain Hex1T Isolated from Soils Contaminated with Used Lubricating Oil in Argentina.

    PubMed

    Luján, Adela M; Feliziani, Sofía; Smania, Andrea M

    2017-01-12

    Pseudomonas aeruginosa Hex1T was isolated from soils contaminated with used lubricating oil from a garage in Córdoba, Argentina. This strain is capable of utilizing this pollutant as the sole carbon and energy source. Here, we present the 6.9-Mb draft genome sequence of Hex1T, which contains many heavy metal-resistance genes. Copyright © 2017 Luján et al.

  4. 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

  5. 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

  6. Whole-Genome Sequence of Multidrug-Resistant Pseudomonas aeruginosa Strain BAMCPA07-48, Isolated from a Combat Injury Wound

    PubMed Central

    Sanjar, Fatemeh; Karna, S. L. Rajasekhar; Chen, Tsute; Chen, Ping; Abercrombie, Johnathan J.

    2016-01-01

    We report here the complete genome sequence of Pseudomonas aeruginosa strain BAMCPA07-48, isolated from a combat injury wound. The closed genome sequence of this isolate is a valuable resource for pathogenome characterization of P. aeruginosa associated with wounds, which will aid in the development of a higher-resolution phylogenomic framework for molecular-guided pathogen-surveillance. PMID:27389262

  7. 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.

  8. Determination of extended spectrum beta-lactamases, metallo-beta-lactamases and AmpC-beta-lactamases among carbapenem resistant Pseudomonas aeruginosa isolated from burn patients.

    PubMed

    Neyestanaki, Davood Kalantar; Mirsalehian, Akbar; Rezagholizadeh, Fereshteh; Jabalameli, Fereshteh; Taherikalani, Morovat; Emaneini, Mohammad

    2014-12-01

    Pseudomonas aeruginosa is an important cause of morbidity and mortality in patients with burns. A total of 214 nonduplicated burn wound isolates of P. aeruginosa were recovered from burn patients. Identification of carbapenem resistant isolates and their antimicrobial susceptibility pattern was carried out using the phenotypic methods. The presence of genes encoding extended spectrum beta-lactamases (ESBLs) and metallo-beta-lactamases (MBLs) enzymes were determined by PCR. The genetic relationships between carbapenem resistant isolates were determined by Random Amplified Polymorphic DNA (RAPD)-PCR. Of 214 investigated P. aeruginosa isolates, 100 (46.7%) were carbapenem resistant. All carbapenem resistant P. aeruginosa were resistant to imipenem, meropenem, ertapenem, carbenicillin, aztreonam, gentamicin and ciprofloxacin but susceptible to polymyxin B. Among 100 carbapenem resistant P. aeruginosa isolates, 3%, 65% and 52% were identified as ESBLs, carbapenemase and AmpC overproduction positive isolates respectively. The most prevalent ESBLs and MBLs genes included blaOXA-10 (97%), blaTEM (61%), blaVIM (55%), blaPER (13%), blaIMP (3%) and blaAIM (1%). RAPD analysis yielded 13 distinct profiles among 92 isolates. A dominant RAPD type was designated as A that consisting of 80 isolates. This is the first report of Adelaide IMipenmase (AIM) MBLs producing P. aeruginosa from Iran and also of the high prevalence of AmpC overproduction isolates. According to the results of current study, P. aeruginosa isolates producing OXA-10, TEM, VIM, PER and IMP beta-lactamases are frequent and the population structures of these isolates are highly similar. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

  9. 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

  10. Inhibition of quorum sensing-mediated biofilm formation in Pseudomonas aeruginosa by a locally isolated Bacillus cereus.

    PubMed

    Wahman, Shaimaa; Emara, Mohamed; Shawky, Riham M; El-Domany, Ramadan A; Aboulwafa, Mohammad Mabrouk

    2015-12-01

    Quorum sensing has been shown to play a crucial role in Pseudomonas aeruginosa pathogenesis where it activates expression of myriad genes that regulate the production of important virulence factors such as biofilm formation. Antagonism of quorum sensing is an excellent target for antimicrobial therapy and represents a novel approach to combat drug resistance. In this study, Chromobacterium violaceum biosensor strain was employed as a fast, sensitive, reliable, and easy to use tool for rapid screening of soil samples for Quorum Sensing Inhibitors (QSI) and the optimal conditions for maximal QSI production were scrutinized. Screening of 127 soil isolates showed that 43 isolates were able to breakdown the HHL signal. Out of the 43 isolates, 38 isolates were able to inhibit the violet color of the biosensor and to form easily detectable zones of color inhibition around their growth. A confirmatory bioassay was carried out after concentrating the putative positive cell-free lysates. Three different isolates that belonged to Bacillus cereus group were shown to have QSI activities and their QSI activities were optimized by changing their culture conditions. Further experiments revealed that the cell-free lysates of these isolates were able to inhibit biofilm formation by P. aeruginosa clinical isolates.

  11. Potential of Ocimum basilicum L. and Salvia officinalis L. essential oils against biofilms of P. aeruginosa clinical isolates.

    PubMed

    Stojanović-Radić, Z; Pejcić, M; Stojanović, N; Sharifi-Rad, J; Stanković, N

    2016-08-29

    Biofilms are complex communities of microorganisms, responsible for more than 60% of the chronic human infections and they represent one of the leading concerns in medicine. Pseudomonas aeruginosa is human pathogenic bacteria which causes numerous diseases and is known for its ability to produce biofilm. Ocimum basilicum L. (basil) and Salvia officinalis L. (sage) are widely used plants in traditional medicine for the treatment of different conditions. Therefore, the aim of this study was to investigate the potential of basil and sage essential oils against P. aeruginosa biofilm producing strains. The efficacy of two essential oils on P. aeruginosa biofilm forming ability was determined using crystal violet method. Out of 15 strains isolated from different clinical biological samples, two were strong, 11 moderate and one weak biofilm producer. Good efficacy of sage essential oil towards strong and weak biofilm producers, but not of basil essential oil, was observed. In the case of moderate biofilm producers, 81.8% showed lower biofilm production after incubation with the sage oil, while 63.6% showed the reduction of biofilm production after basil essential oil treatment. The obtained results showed high potential of both oils for the treatment of persistent infections caused by Pseudomonas aeruginosa biofilms.

  12. [Acanthamoeba, naturally intracellularly infected with Pseudomonas aeruginosa, after their isolation from a microbiologically contaminated drinking water system in a hospital].

    PubMed

    Michel, R; Burghardt, H; Bergmann, H

    1995-03-01

    The drinking water system of a new hospital building that was highly contaminated with bacteria before opening was investigated too for the prevalence of small free living amoebae. Germ counts resulted in > 100 CFU/ml in 100% of the cold water samples, that showed also growth of P. aeruginosa, whereas E. coli and coliforme bacteria could not be identified. The investigation of 37 water samples for protozoa revealed growth of small freeliving amoebae in 20 samples (54%) belonging to 10 species of the genus Acanthamoeba, Naegleria, Hartmannella, Echinamoeba among others. In addition 2 Ciliate- and 2 Microflagellate-species could be observed. While all Naegleria strains isolated belonged to the N. gruberi-complex two of 16 Acanthamoeba-isolates proved to be pathogenic for laboratory mice. From 7 watersamples positive with P. aeruginosa 5 Acanthamoeba- and 2 Echinamoeba strains could be isolated which revealed intracellular multiplication of P. aeruginosa. Because of their well known resistances against chlorine, the amoebae and their cysts are considered to be vectors for these intracellular bacteria. A complete sanitation of the incriminated drinking water system was accomplished by combined chemical and thermic disinfection measures.

  13. Waste Isolation Pilot Plant Environmental Monitoring Plan

    SciTech Connect

    None, None

    2008-03-12

    U.S. Department of Energy (DOE) Order 450.1, Environmental Protection Program, requires each DOE site to conduct environmental monitoring. Environmental monitoring at the Waste Isolation Pilot Plant (WIPP) is conducted in order to: (a) Verify and support compliance with applicable federal, state, and local environmental laws, regulations, permits, and orders; (b) Establish baselines and characterize trends in the physical, chemical, and biological condition of effluent and environmental media; (c) Identify potential environmental problems and evaluate the need for remedial actions or measures to mitigate the problems; (d) Detect, characterize, and report unplanned releases; (e) Evaluate the effectiveness of effluent treatment and control, and pollution abatement programs; and (f) Determine compliance with commitments made in environmental impact statements, environmental assessments, safety analysis reports, or other official DOE documents. This Environmental Monitoring Plan (EMP) explains the rationale and design criteria for the environmental monitoring program, extent and frequency of monitoring and measurements, procedures for laboratory analyses, quality assurance (QA) requirements, program implementation procedures, and direction for the preparation and disposition of reports. Changes to the environmental monitoring program may be necessary to allow the use of advanced technology and new data collection techniques. This EMP will document changes in the environmental monitoring program. Guidance for preparation of EMPs is contained in DOE/EH-0173T, Environmental Regulatory Guide for Radiological Effluent Monitoring and Environmental Surveillance.

  14. Phenotypic Characterization of Clonal and Nonclonal Pseudomonas aeruginosa Strains Isolated from Lungs of Adults with Cystic Fibrosis▿

    PubMed Central

    Tingpej, Pholawat; Smith, Lucas; Rose, Barbara; Zhu, Hua; Conibear, Tim; Al Nassafi, Khaled; Manos, Jim; Elkins, Mark; Bye, Peter; Willcox, Mark; Bell, Scott; Wainwright, Claire; Harbour, Colin

    2007-01-01

    The emergence of virulent Pseudomonas aeruginosa clones is a threat to cystic fibrosis (CF) patients globally. Characterization of clonal P. aeruginosa strains is critical for an understanding of its clinical impact and developing strategies to meet this problem. Two clonal strains (AES-1 and AES-2) are circulating within CF centers in eastern Australia. In this study, phenotypic characteristics of 43 (14 AES-1, 5 AES-2, and 24 nonclonal) P. aeruginosa isolates were compared to gain insight into the properties of clonal strains. All 43 isolates produced bands of the predicted size in PCRs for vfr, rhlI, rhlR, lasA, lasB, aprA, rhlAB, and exoS genes; 42 were positive for lasI and lasR, and none had exoU. Thirty-seven (86%) isolates were positive in total protease assays; on zymography, 24 (56%) produced elastase/staphylolysin and 22 (51%) produced alkaline protease. Clonal isolates were more likely than nonclonal isolates to be positive for total proteases (P = 0.02), to show elastase and alkaline protease activity by zymography (P = 0.04 and P = 0.01, respectively), and to show elastase activity by the elastin-Congo red assay (P = 0.04). There were no other associations with genotype. Overall, increasing patient age was associated with decreasing elastase activity (P = 0.03). Thirty-two (74%) isolates had at least one N-acylhomoserine lactone (AHL) by thin-layer chromatography. rhl-associated AHL detection was associated with the production and level of total protease and elastase activity (all P < 0.01). Thirty-three (77%) isolates were positive for ExoS by Western blot analysis, 35 (81%) produced rhamnolipids, and 34 (79%) showed chitinase activity. Findings suggest that protease activity during chronic infection may contribute to the transmissibility or virulence of these clonal strains. PMID:17392437

  15. Enhancement of Rhamnolipid Production in Residual Soybean Oil by an Isolated Strain of Pseudomonas aeruginosa

    NASA Astrophysics Data System (ADS)

    de Lima, C. J. B.; França, F. P.; Sérvulo, E. F. C.; Resende, M. M.; Cardoso, V. L.

    In the present work, the production of rhamnolipid from residual soybean oil (RSO) from food frying facilities was studied using a strain of Pseudomonas aeruginosa of contaminated lagoon, isolated from a hydrocarbon contaminated soil. The optimization of RSO, amonium nitrate, and brewery residual yeast concentrations was accomplished by a central composite experimental design and surface response analysis. The experiments were performed in 500-mL Erlenmeyer flasks containing 50mL of mineral medium, at 170 rpm and 30±1°C, for a 48-h fermentation period. Rhamnolipid production has been monitored by measurements of surface tension, rhamnose concentration, and emulsifying activity. The best-planned results, located on the central point, have corresponded to 22g/L of RSO, 5.625 g/ L of NH4NO3' and 11.5 g/L of brewery yeast. At the maximum point the values for rhamnose and emulsifying index were 2.2g/L and 100%, respectively.

  16. Isolation of dicarboxylic acid- and glucose-binding proteins from Pseudomonas aeruginosa.

    PubMed Central

    Stinson, M W; Cohen, M A; Merrick, J M

    1976-01-01

    Inducible binding proteins for C4-dicarboxylic acids (DBP) and glucose (GBP) were isolated from Pseudomonas aeruginosa by extraction of exponential-phase cells with 0.2 M MgC12 (pH 8.5) and by an osmotic shock procedure without affecting cell viability. DBP synthesis was induced by growth on aspartate, alpha-ketoglutarate, succinate, fumarate, malate, and malonate but not by growth on acetate, citrate, pyruvate, or glucose. Binding of succinate by DBP was competitively inhibited by 10-fold concentrations of fumarate and malate but not by a variety of related substances. GBP synthesis and transport of methyl alpha-glucoside by whole cells were induced by growth on glucose or pyruvate plus galactose, 2-deoxyglucose, or methyl alpha-glucoside but not by growth on gluconate, succinate, acetate, or pyruvate. The binding of radioactive glucose by GBP was significantly inhibited by 10-fold concentrations of glucose, galactose, and glucose-1-phosphate but not by the other carbohydrates tested. The binding of glucose by GBP or succinate by DBP did not result in any chemical alteration of the substrates. PMID:824281

  17. Serotyping and Cross-Reactivity's Between Different Pseudomonas aeruginosa Isolates Prevalent in Iran

    PubMed Central

    Ahmadi, H; Maleknia, S; Tabaraie, B; Norouzian, D; Poormirza-gholi, F; Nejati, M; Hedayati, MH; Beik Mohammadi, MR; Behnoodi, A; Izadpanahi, M

    2010-01-01

    Background and Objectives 300 Pseudomonas aeruginosa strains were isolated from hospitalized patients in Iran. Using international antigenic typing system (IATS) antibodies, all strains were classified into 16 serotypes while serotype 14 was not identified among the 17 known serotypes. To evaluate the rate of cross-reactivity between O- antigenic determinants, monospecific polyclonal antibodies were made against whole-killed-cells and live cells of each serotype. Materials and Methods Each antiserum was challenged against homologous and heterologous antigens using slide agglutination test. The degree of agglutination reaction is shown by –ve, 1+ve, 2+ve, 3+ve and 4+ve for 0, 25%, 50%, 75% and 100% agglutination respectively. Then, the results were tabulated for further study. Results The rate of cross-reactivity between O-antigenic determinants demonstrated that strains 10.55 and 15.14 had the highest agglutination reaction with serum of all the homologous and heterologous serotypes. Conclusion Evaluation of the results obtained from the present study can be applied in production of reliable vaccines and antisera as therapeutic agents or as diagnostic kits. PMID:22347554

  18. Isolation and engineering of plant growth promoting rhizobacteria Pseudomonas aeruginosa for enhanced cadmium bioremediation.

    PubMed

    Huang, Junli; Liu, Zhaobing; Li, Shiyu; Xu, Bo; Gong, Yahui; Yang, Yan; Sun, Hanxiao

    2016-11-25

    Although many bacteria are tolerant to heavy metals and play important roles in the immobilization of heavy metals, they cannot always be dependably reproduced under field conditions. In this work, a cadmium (Cd)-resistant bacterium was isolated from a Cd-contaminated oil field and identified as Pseudomonas aeruginosa (Pse-w). We then determined various plant growth promoting features such as the solubilization of phosphate, and the production of indole-3-acetic acid and siderophores. Lastly, we engineered the strain Pse-w-MT by targeting metallothioneins to the cell surface of Pse-w to immobilize Cd(2+) and promote plant growth. Our data revealed that Pse-w exhibited high levels of resistance to Cd(2+) (4 mM) and showed various plant growth promoting features. The engineered strain Pse-w-MT was found to adsorb Cd(2+) mainly via extracellular deposition, and had an enhanced ability for immobilizing Cd(2+) ions from the external media. Furthermore, the inoculation of Cd-polluted soil with Pse-w-MT significantly elevated the shoot and root biomass and leaf chlorophyll content. Similarly, plants inoculated with Pse-w-MT demonstrated markedly lower Cd(2+) accumulation in the root and shoot system. It was concluded that plant growth promoting rhizobacteria with a high Cd(2+) tolerance was an ideal candidate to be engineered for bioremediation and plant growth promotion against Cd-induced stress.

  19. Evaluation of the In Vitro Activity of Ceftazidime-Avibactam and Ceftolozane-Tazobactam against Meropenem-Resistant Pseudomonas aeruginosa Isolates

    PubMed Central

    Buehrle, Deanna J.; Shields, Ryan K.; Chen, Liang; Hao, Binghua; Press, Ellen G.; Alkrouk, Ammar; Potoski, Brian A.; Kreiswirth, Barry N.; Nguyen, M. Hong

    2016-01-01

    We compared ceftazidime-avibactam, ceftolozane-tazobactam, ceftazidime, cefepime, and piperacillin-tazobactam MICs for 38 meropenem-resistant Pseudomonas aeruginosa isolates. No isolates harbored carbapenemases; 74% were oprD mutants. Ceftazidime-avibactam and ceftolozane-tazobactam were active against 92% of the isolates, including 80% that were resistant to all three β-lactams. Forty-three percent of ceftazidime-avibactam-susceptible isolates and 6% of ceftolozane-tazobactam-susceptible isolates exhibited MICs at the respective breakpoints. Ceftolozane-tazobactam and ceftazidime-avibactam are therapeutic options for meropenem-resistant P. aeruginosa infections that should be used judiciously to preserve activity. PMID:26976862

  20. Environmental variation alters the fitness effects of rifampicin resistance mutations in Pseudomonas aeruginosa.

    PubMed

    Gifford, Danna R; Moss, Ethan; MacLean, R Craig

    2016-03-01

    The fitness effects of antibiotic resistance mutations in antibiotic-free conditions play a key role in determining the long-term maintenance of resistance. Although resistance is usually associated with a cost, the impact of environmental variation on the cost of resistance is poorly understood. Here, we test the impact of heterogeneity in temperature and resource availability on the fitness effects of antibiotic resistance using strains of the pathogenic bacterium Pseudomonas aeruginosa carrying clinically important rifampicin resistance mutations. Although the rank order of fitness was generally maintained across environments, fitness effects relative to the wild type differed significantly. Changes in temperature had a profound impact on the fitness effects of resistance, whereas changes in carbon substrate had only a weak impact. This suggests that environmental heterogeneity may influence whether the costs of resistance are likely to be ameliorated by second-site compensatory mutations or by reversion to wild-type rpoB. Our results highlight the need to consider environmental heterogeneity and genotype-by-environment interactions for fitness in models of resistance evolution.

  1. Synthesis and electrochemical detection of a thiazolyl-indole natural product isolated from the nosocomial pathogen Pseudomonas aeruginosa.

    PubMed

    Buzid, Alyah; Muimhneacháin, Eoin Ó; Reen, F Jerry; Hayes, Phyllis E; Pardo, Leticia M; Shang, Fengjun; O'Gara, Fergal; Sperry, Jonathan; Luong, John H T; Glennon, Jeremy D; McGlacken, Gerard P

    2016-09-01

    Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen, capable of surviving in a broad range of natural environments and quickly acquiring resistance. It is associated with hospital-acquired infections, particularly in patients with compromised immunity, and is the primary cause of morbidity and mortality in cystic fibrosis (CF) patients. P. aeruginosa is also of nosocomial importance on dairy farms and veterinary hospitals, where it is a key morbidity factor in bovine mastitis. P. aeruginosa uses a cell-cell communication system consisting of signalling molecules to coordinate bacterial secondary metabolites, biofilm formation, and virulence. Simple and sensitive methods for the detection of biomolecules as indicators of P. aeruginosa infection would be of great clinical importance. Here, we report the synthesis of the P. aeruginosa natural product, barakacin, which was recently isolated from the bovine ruminal strain ZIO. A simple and sensitive electrochemical method was used for barakacin detection using a boron-doped diamond (BDD) and glassy carbon (GC) electrodes, based on cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The influence of electrolyte pH on the peak potential and peak currents was also investigated. At pH 2.0, the peak current was linearly dependent on barakacin concentration (in the range used, 1-10 μM), with correlation coefficients greater than 0.98 on both electrodes. The detection limit (S/N = 3) on the BDD electrode was 100-fold lower than that obtained on the GC electrode. The optimized method using the BDD electrode was extended to bovine (cow feces) and human (sputum of a CF patient) samples. Spiked barakacin was easily detected in these matrices at a limit of 0.5 and 0.05 μM, respectively. Graphical abstract Electrochemical detection of barakacin.

  2. An Investigation of Antibacterial Resistance Patterns Among Acinetobacter baumannii and Pseudomonas aeruginosa Isolates Collected from Intensive Care Units of a University-Affiliated Hospital in Ahvaz, Iran

    PubMed Central

    Izadpour, Farrokh; Ranjbari, Nastaran; Aramesh, Mohammad-Reza; Moosavian, Mojtaba; ShahAli, Shiva; Larki, Farzaneh; Tabesh, Hamed; Morvaridi, Afrooz

    2016-01-01

    Background In recent decades, multidrug-resistant non-fermenting Gram-negative pathogens, particularly Acinetobacter baumannii and Pseudomonas aeruginosa, have been recognized as a major cause of healthcare-associated and nosocomial infections and outbreaks. Objectives The aim of this study was to determine the prevalence and pattern of antibiotic resistance in A. baumannii and P. aeruginosa isolates collected from intensive care units (ICUs). Methods One hundred fifty-five clinical isolates, including 80 (51.6%) isolates of A. baumannii and 75 (48.4%) isolates of P. aeruginosa, from hospitalized patients in the ICUs of a teaching hospital in Ahvaz, Iran, were collected from January 1 to December 30, 2013. The organisms were identified with conventional bacteriological methods, and antimicrobial susceptibility testing was performed on all isolates in accordance with clinical laboratory and standards institute (CLSI) guidelines. Results The maximum resistance rates among A. baumannii isolates were observed for ciprofloxacin and trimethoprim-sulfamethoxazole (96.9% and 95.2%, respectively). For P. aeruginosa isolates, the maximum resistance rates were reported for ceftriaxone and trimethoprim-sulfamethoxazole (97.2% and 92.4%, respectively). Conclusions The majority of A. baumannii and P. aeruginosa isolates were found to be resistant to commonly recommended antibiotics. Therefore, surveillance of antibiotic consumption and proper antibiotic administration guidelines are essential for preventing major outbreaks in the future. PMID:27800136

  3. Sequence Types 235, 111, and 132 Predominate among Multidrug-Resistant Pseudomonas aeruginosa Clinical Isolates in Croatia

    PubMed Central

    Izdebski, Radosław; Butic, Iva; Jelic, Marko; Abram, Maja; Koscak, Iva; Baraniak, Anna; Hryniewicz, Waleria; Gniadkowski, Marek; Tambic Andrasevic, Arjana

    2014-01-01

    A population analysis of 103 multidrug-resistant Pseudomonas aeruginosa isolates from Croatian hospitals was performed. Twelve sequence types (STs) were identified, with a predominance of international clones ST235 (serotype O11 [41%]), ST111 (serotype O12 [15%]), and ST132 (serotype O6 [11%]). Overexpression of the natural AmpC cephalosporinase was common (42%), but only a few ST235 or ST111 isolates produced VIM-1 or VIM-2 metallo-β-lactamases or PER-1 or GES-7 extended-spectrum β-lactamases. PMID:25070098

  4. Nutritional requirement among Pseudomonas aeruginosa isolates recovered from respiratory clinical specimens at a tertiary hospital from South of Brazil

    PubMed Central

    Perez, Leandro Reus Rodrigues; de Freitas, Ana Lúcia Peixoto; Barth, Afonso Luís

    2011-01-01

    We screened 349 isolates of P. aeruginosa from cystic fibrosis (CF+) and non-cystic fibrosis (CF-) patients for the auxotrophy. Fourteen (4.0%) were auxotrophic and among them only one was recovered from CF-patient showing that this characteristic is strongly associated with cystic fibrosis. In total, a requirement for 5 different compounds (or combination) was verified and, of these, methionine was the most common single amino acid required. Only one auxotrophic isolate was no able to produce biofilm in vitro. PMID:24031723

  5. Label-free SRM-based relative quantification of antibiotic resistance mechanisms in Pseudomonas aeruginosa clinical isolates.

    PubMed

    Charretier, Yannick; Köhler, Thilo; Cecchini, Tiphaine; Bardet, Chloé; Cherkaoui, Abdessalam; Llanes, Catherine; Bogaerts, Pierre; Chatellier, Sonia; Charrier, Jean-Philippe; Schrenzel, Jacques

    2015-01-01

    Both acquired and intrinsic mechanisms play a crucial role in Pseudomonas aeruginosa antibiotic resistance. Many clinically relevant resistance mechanisms result from changes in gene expression, namely multidrug efflux pump overproduction, AmpC β-lactamase induction or derepression, and inactivation or repression of the carbapenem-specific porin OprD. Changes in gene expression are usually assessed using reverse-transcription quantitative real-time PCR (RT-qPCR) assays. Here, we evaluated label-free Selected Reaction Monitoring (SRM)-based mass spectrometry to directly quantify proteins involved in antibiotic resistance. We evaluated the label-free SRM using a defined set of P. aeruginosa isolates with known resistance mechanisms and compared it with RT-qPCR. Referring to efflux systems, we found a more robust relative quantification of antibiotic resistance mechanisms by SRM than RT-qPCR. The SRM-based approach was applied to a set of clinical P. aeruginosa isolates to detect antibiotic resistance proteins. This multiplexed SRM-based approach is a rapid and reliable method for the simultaneous detection and quantification of resistance mechanisms and we demonstrate its relevance for antibiotic resistance prediction.

  6. A Pseudomonas aeruginosa strain isolated from a contact lens-induced acute red eye (CLARE) is protease-deficient.

    PubMed

    Estrellas, P S; Alionte, L G; Hobden, J A

    2000-03-01

    Pseudomonas aeruginosa proteases are thought to be important virulence factors in the pathogenesis of corneal disease. This study examined protease production from two strains of P. aeruginosa responsible for two very distinct clinical diseases: strain Paer1, isolated from a Contact Lens-induced Acute Red Eye (CLARE), and strain KEI 1025, isolated from a corneal ulcer. Strains were compared to a laboratory strain (ATCC 19660) known to produce severe keratitis in experimentally infected mice for protease production and for ocular virulence. Protease production was examined with colorimetric assays, gelatin zymography and western blots. Elastase A activity was quantitated with a staphylolytic assay. Ocular virulence was examined using a mouse scratch model of keratitis. In contrast to strains KEI 1025 or ATCC 19660, Paer1 was unable to produce enzymatically active elastase A, elastase, and protease IV. All three strains produced active alkaline protease. Strains KEI 1025 and ATCC 19660 produced a fulminant keratitis in mice whereas Paer1 produced a mild transient infection. Restoration of elastase activity in Paer1 via genetic complementation did not result in a virulent phenotype. Co-infection of mouse eyes with strains Paer1 and ATCC 19660 resulted in the eventual loss of Paer1 from corneal tissue. These studies suggest that P. aeruginosa elastase A and/or protease IV, but not alkaline protease or elastase, contribute to the ocular virulence of this organism.

  7. Label-free SRM-based relative quantification of antibiotic resistance mechanisms in Pseudomonas aeruginosa clinical isolates

    PubMed Central

    Charretier, Yannick; Köhler, Thilo; Cecchini, Tiphaine; Bardet, Chloé; Cherkaoui, Abdessalam; Llanes, Catherine; Bogaerts, Pierre; Chatellier, Sonia; Charrier, Jean-Philippe; Schrenzel, Jacques

    2015-01-01

    Both acquired and intrinsic mechanisms play a crucial role in Pseudomonas aeruginosa antibiotic resistance. Many clinically relevant resistance mechanisms result from changes in gene expression, namely multidrug efflux pump overproduction, AmpC β-lactamase induction or derepression, and inactivation or repression of the carbapenem-specific porin OprD. Changes in gene expression are usually assessed using reverse-transcription quantitative real-time PCR (RT-qPCR) assays. Here, we evaluated label-free Selected Reaction Monitoring (SRM)-based mass spectrometry to directly quantify proteins involved in antibiotic resistance. We evaluated the label-free SRM using a defined set of P. aeruginosa isolates with known resistance mechanisms and compared it with RT-qPCR. Referring to efflux systems, we found a more robust relative quantification of antibiotic resistance mechanisms by SRM than RT-qPCR. The SRM-based approach was applied to a set of clinical P. aeruginosa isolates to detect antibiotic resistance proteins. This multiplexed SRM-based approach is a rapid and reliable method for the simultaneous detection and quantification of resistance mechanisms and we demonstrate its relevance for antibiotic resistance prediction. PMID:25713571

  8. Mechanisms of intrinsic resistance and acquired susceptibility of Pseudomonas aeruginosa isolated from cystic fibrosis patients to temocillin, a revived antibiotic

    PubMed Central

    Chalhoub, Hussein; Pletzer, Daniel; Weingart, Helge; Braun, Yvonne; Tunney, Michael M.; Elborn, J. Stuart; Rodriguez-Villalobos, Hector; Plésiat, Patrick; Kahl, Barbara C.; Denis, Olivier; Winterhalter, Mathias; Tulkens, Paul M.; Van Bambeke, Françoise

    2017-01-01

    The β-lactam antibiotic temocillin (6-α-methoxy-ticarcillin) shows stability to most extended spectrum β-lactamases, but is considered inactive against Pseudomonas aeruginosa. Mutations in the MexAB-OprM efflux system, naturally occurring in cystic fibrosis (CF) isolates, have been previously shown to reverse this intrinsic resistance. In the present study, we measured temocillin activity in a large collection (n = 333) of P. aeruginosa CF isolates. 29% of the isolates had MICs ≤ 16 mg/L (proposed clinical breakpoint for temocillin). Mutations were observed in mexA or mexB in isolates for which temocillin MIC was ≤512 mg/L (nucleotide insertions or deletions, premature termination, tandem repeat, nonstop, and missense mutations). A correlation was observed between temocillin MICs and efflux rate of N-phenyl-1-naphthylamine (MexAB-OprM fluorescent substrate) and extracellular exopolysaccharide abundance (contributing to a mucoid phenotype). OpdK or OpdF anion-specific porins expression decreased temocillin MIC by ~1 two-fold dilution only. Contrarily to the common assumption that temocillin is inactive on P. aeruginosa, we show here clinically-exploitable MICs on a non-negligible proportion of CF isolates, explained by a wide diversity of mutations in mexA and/or mexB. In a broader context, this work contributes to increase our understanding of MexAB-OprM functionality and help delineating how antibiotics interact with MexA and MexB. PMID:28091521

  9. The frequency of class1 and 2 integrons in Pseudomonas aeruginosa strains isolated from burn patients in a burn center of Ahvaz, Iran.

    PubMed

    Khosravi, Azar Dokht; Motahar, Moloudsadat; Abbasi Montazeri, Effat

    2017-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen with the ability to cause severe nosocomial infections and remains a major problem in burn patients. This organism shows a remarkable antimicrobial resistance and is often resistant to multiple antibiotics. Integron genes as mobile genetic elements are playing an important role in the spread of P. aeruginosa antibiotic resistance. This study was aimed to investigate the occurrence of class 1, and 2 integron genes (int1, int2), among P. aeruginosa strains isolated from patients with burn infections. In total 93 clinical isolates of P. aeruginosa were screened. The antimicrobial susceptibilities of 9 common antimicrobial agents were tested against the isolates using disk diffusion method. PCR amplification was performed on extracted DNAs for the detection of int1, and int2 genes using the set of specific primers. The majority of P. aeruginosa isolates were from wound infection (69.9%). In disk diffusion method, most isolates showed remarkable resistance to tested antibiotics with highest against gentamicin (94.62%) and ciprofloxacin (93.55%). PCR amplification revealed that 89(95.7%) of P. aeruginosa strains carried int1, but none of them harbored int2 genes. The distribution of int1 gene was highest in blood (100%), followed by wound isolates (95.38%). We demonstrated a high antimicrobial resistance among P. aeruginosa isolates in our setting. int1 was prevalent and seems to play an important role in multidrug resistance among the isolates. So, performance of antibiotic surveillance programs is necessary for choosing the appropriate therapy and management of infection control practices.

  10. Detection of Quorum Sensing Activity in the Multidrug-Resistant Clinical Isolate Pseudomonas aeruginosa Strain GB11

    PubMed Central

    Cheng, Huey Jia; Ee, Robson; Cheong, Yuet Meng; Tan, Wen-Si; Yin, Wai-Fong; Chan, Kok-Gan

    2014-01-01

    A multidrug-resistant clinical bacteria strain GB11 was isolated from a wound swab on the leg of a patient. Identity of stain GB11 as Pseudomonas aeruginosa was validated by using matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Detection of the production of signaling molecules, N-acylhomoserine lactones (AHLs), was conducted using three different bacterial biosensors. A total of four different AHLs were found to be produced by strain GB11, namely N-butyryl homoserine lactone (C4-HSL), N-hexanoylhomoserine lactone (C6-HSL), N-octanoyl homoserine lactone (C8-HSL) and N-3-oxo-dodecanoylhomoserine lactone (3-oxo-C12-HSL) using high resolution liquid chromatography tandem mass spectrometry (LC-MS/MS). Of these detected AHLs, 3-oxo-C12-HSL was found to be the most abundant AHL produced by P. aeruginosa GB11. PMID:25019635

  11. Characterization of exo-s, exo-u, and alg virulence factors and antimicrobial resistance in Pseudomonas aeruginosa isolated from migratory Egyptian vultures from India.

    PubMed

    Sharma, Pradeep; Faridi, Farah; Mir, Irfan A; Sharma, Sandeep K

    2014-01-01

    This study of Pseudomonas aeruginosa in fecal droppings of migratory Egyptian vultures (Neophron p. percnopterus) revealed eight positive samples (n=25) by a 16S rRNA gene-based PCR in two consecutive winter seasons. Disk diffusion sensitivity testing revealed three multiple antimicrobial resistant (MAR) isolates. Genotypic characterization showed mutually exclusive exo-s and exo-u virulence genes in five and three isolates, respectively, while the alg gene was present in all of the isolates. MAR isolates with virulence genes were detected in both seasons. The Egyptian vultures could potentially be vectors of pathogenic and MAR P. aeruginosa, thereby affecting regional control and preventive measures.

  12. Plasmid Profile Analysis and bla VIM Gene Detection of Metalo β-lactamase (MBL) Producing Pseudomonas aeruginosa Isolates from Clinical Samples

    PubMed Central

    M, Jeya

    2014-01-01

    Introduction:Pseudomonas aeruginosa is a frequent colonizer of hospitalized patients. They are responsible for serious infections such as meningitis, urological infections, septicemia and pneumonia. Carbapenem resistance of Pseudomonas aeruginosa is currently increasingly reported which is often mediated by production of metallo-β-lactamase (MBL). Multidrug resistant Pseudomonas aeruginosa isolates may involve reduced cell wall permeability, production of chromosomal and plasmid mediated β lactamases, aminoglycosides modifying enzymes and an active multidrug efflux mechanism. Objective: This study is aimed to detect the presence and the nature of plasmids among metallo-β-lactamase producing Pseudomonas aeruginosa isolates. Also to detect the presence of bla VIM gene from these isolates. Materials and Methods: Clinical isolates of Pseudomonas aeruginosa showing the metalo-β-lactamase enzyme (MBL) production were isolated. The MBL production was confirmed by three different methods. From the MBL producing isolates plasmid extraction was done by alkaline lysis method. Plasmid positive isolates were subjected for blaVIM gene detection by PCR method. Results: Two thousand seventy six clinical samples yielded 316 (15.22%) Pseudomonas aeruginosa isolates, out of which 141 (44.62%) were multidrug resistant. Among them 25 (17.73%) were metallo-β-lactamase enzyme producers. Plasmids were extracted from 18 out of 25 isolates tested. Five out of 18 isolates were positive for the blaVIM gene detection by the PCR amplification. Conclusion: The MBL producers were susceptible to polymyxin /colistin with MIC ranging from 0.5 – 2μg/ml. Molecular detection of specific genes bla VIM were positive among the carbapenem resistant isolates. PMID:25120980

  13. Waste Isolation Pilot Plant Environmental Monitoring Plan

    SciTech Connect

    Washington Regulatory and Environmental Services; Washington TRU Solutions LLC

    2004-02-19

    U.S. Department of Energy (DOE) Order 450.1, Environmental Protection Program, requires each DOE site to conduct environmental monitoring. Environmental monitoring at the Waste Isolation Pilot Plant (WIPP) is conducted in order to: (a) Verify and support compliance with applicable federal, state, and local environmental laws, regulations, permits, and orders; (b) Establish baselines and characterize trends in the physical, chemical, and biological condition of effluent and environmental media; (c) Identify potential environmental problems and evaluate the need for remedial actions or measures to mitigate the problem; (d) Detect, characterize, and report unplanned releases; (e) Evaluate the effectiveness of effluent treatment and control, and pollution abatement programs; and (f) Determine compliance with commitments made in environmental impact statements, environmental assessments, safety analysis reports, or other official DOE documents. This Environmental Monitoring Plan (EMP) has been written to contain the rationale and design criteria for the monitoring program, extent and frequency of monitoring and measurements, procedures for laboratory analyses, quality assurance (QA) requirements, program implementation procedures, and direction for the preparation and disposition of reports. Changes to the environmental monitoring program may be necessary to allow the use of advanced technology and new data collection techniques. This EMP will document any proposed changes in the environmental monitoring program. Guidance for preparation of Environmental Monitoring Plans is contained in DOE/EH-0173T, Environmental Regulatory Guide for Radiological Effluent Monitoring and Environmental Surveillance. The plan will be effective when it is approved by the appropriate Head of Field Organization or their designee. The plan discusses major environmental monitoring and hydrology activities at the WIPP and describes the programs established to ensure that WIPP operations do not

  14. Isolation and Characterization of a Cyanophage Infecting the Toxic Cyanobacterium Microcystis aeruginosa

    PubMed Central

    Yoshida, Takashi; Takashima, Yukari; Tomaru, Yuji; Shirai, Yoko; Takao, Yoshitake; Hiroishi, Shingo; Nagasaki, Keizo

    2006-01-01

    We isolated a cyanophage (Ma-LMM01) that specifically infects a toxic strain of the bloom-forming cyanobacterium Microcystis aeruginosa. Transmission electron microscopy showed that the virion is composed of anisometric head and a tail complex consisting of a central tube and a contractile sheath with helical symmetry. The morphological features and the host specificity suggest that Ma-LMM01 is a member of the cyanomyovirus group. Using semi-one-step growth experiments, the latent period and burst size were estimated to be 6 to 12 h and 50 to 120 infectious units per cell, respectively. The size of the phage genome was estimated to be ca. 160 kbp using pulse-field gel electrophoresis; the nucleic acid was sensitive to DNase I, Bal31, and all 14 restriction enzymes tested, suggesting that it is a linear double-stranded DNA having a low level of methylation. Phylogenetic analyses based on the deduced amino acid sequences of two open reading frames coding for ribonucleotide reductase alpha- and beta-subunits showed that Ma-LMM01 forms a sister group with marine and freshwater cyanobacteria and is apparently distinct from T4-like phages. Phylogenetic analysis of the deduced amino acid sequence of the putative sheath protein showed that Ma-LMM01 does not form a monophyletic group with either the T4-like phages or prophages, suggesting that Ma-LMM01 is distinct from other T4-like phages that have been described despite morphological similarity. The host-phage system which we studied is expected to contribute to our understanding of the ecology of Microcystis blooms and the genetics of cyanophages, and our results suggest the phages could be used to control toxic cyanobacterial blooms. PMID:16461672

  15. Cystic Fibrosis Isolates of Pseudomonas aeruginosa Retain Iron-Regulated Antimicrobial Activity against Staphylococcus aureus through the Action of Multiple Alkylquinolones

    PubMed Central

    Nguyen, Angela T.; Jones, Jace W.; Cámara, Miguel; Williams, Paul; Kane, Maureen A.; Oglesby-Sherrouse, Amanda G.

    2016-01-01

    Cystic fibrosis (CF) is a hereditary disease that predisposes individuals to pulmonary dysfunction and chronic infections. Early infection of the CF lung with Staphylococcus aureus is common, while Pseudomonas aeruginosa becomes dominant as disease progresses. Emergence of P. aeruginosa likely depends on the action of multiple 2-alkyl-4-(1H)-quinolones (AQ) secreted by this organism. We recently showed that antimicrobial activity against S. aureus is enhanced by iron depletion and is dependent upon multiple AQ metabolites. Two of these AQs, the Pseudomonas quinolone signal [PQS; 2-heptyl-3-hydroxy-4(1H)-quinolone] and 2-heptyl-4-hydroxyquinoline (HHQ), are quorum sensing molecules that activate the expression of multiple microbicidal factors. Here we show for the first time that HHQ also exhibits innate antimicrobial activity against S. aureus. We further show that iron depletion potentiates the antistaphylococcal activity of HHQ, as well as 2-heptyl-4-hydroxyquinoline-N-oxide (HQNO), another AQ that functions as a cytochrome B inhibitor. Notably, we found that deletion of the genes for the terminal biosynthetic steps for either PQS or HQNO results in overproduction of the HHQ intermediate, likely maintaining the ability of these mutants to mediate antimicrobial activity. Compensatory increases in HHQ were also observed in PQS-deficient CF isolates, which also retained the ability to mediate iron-regulated antimicrobial activity against S. aureus. These studies demonstrate that iron-regulated antimicrobial activity of P. aeruginosa against S. aureus is due to the cumulative effects of multiple AQ metabolites, both the production and activity of which are modulated by environmental iron levels. PMID:27512392

  16. Cystic Fibrosis Isolates of Pseudomonas aeruginosa Retain Iron-Regulated Antimicrobial Activity against Staphylococcus aureus through the Action of Multiple Alkylquinolones.

    PubMed

    Nguyen, Angela T; Jones, Jace W; Cámara, Miguel; Williams, Paul; Kane, Maureen A; Oglesby-Sherrouse, Amanda G

    2016-01-01

    Cystic fibrosis (CF) is a hereditary disease that predisposes individuals to pulmonary dysfunction and chronic infections. Early infection of the CF lung with Staphylococcus aureus is common, while Pseudomonas aeruginosa becomes dominant as disease progresses. Emergence of P. aeruginosa likely depends on the action of multiple 2-alkyl-4-(1H)-quinolones (AQ) secreted by this organism. We recently showed that antimicrobial activity against S. aureus is enhanced by iron depletion and is dependent upon multiple AQ metabolites. Two of these AQs, the Pseudomonas quinolone signal [PQS; 2-heptyl-3-hydroxy-4(1H)-quinolone] and 2-heptyl-4-hydroxyquinoline (HHQ), are quorum sensing molecules that activate the expression of multiple microbicidal factors. Here we show for the first time that HHQ also exhibits innate antimicrobial activity against S. aureus. We further show that iron depletion potentiates the antistaphylococcal activity of HHQ, as well as 2-heptyl-4-hydroxyquinoline-N-oxide (HQNO), another AQ that functions as a cytochrome B inhibitor. Notably, we found that deletion of the genes for the terminal biosynthetic steps for either PQS or HQNO results in overproduction of the HHQ intermediate, likely maintaining the ability of these mutants to mediate antimicrobial activity. Compensatory increases in HHQ were also observed in PQS-deficient CF isolates, which also retained the ability to mediate iron-regulated antimicrobial activity against S. aureus. These studies demonstrate that iron-regulated antimicrobial activity of P. aeruginosa against S. aureus is due to the cumulative effects of multiple AQ metabolites, both the production and activity of which are modulated by environmental iron levels.

  17. [Investigation of antimicrobial resistance of Klebsiella pneumoniae and Pseudomonas aeruginosa isolates from rat-like animals around a hospital in Guangzhou].

    PubMed

    Zhong, Xue-Shan; Ge, Jing; Chen, Shao-Wei; Xiong, Yi-Quan; Zheng, Xue-Yan; Qiu, Min; Huo, Shu-Ting; Chen, Qing

    2016-05-01

    To investigate antimicrobial resistance of Klebsiella pneumoniae and Pseudomonas aeruginosa isolates in fecal samples from rat-like animals. Rat-like animals were captured using cages around a hospital and the neighboring residential area between March and October, 2015. K. pneumoniae and P. aeruginosa were isolated from the fecal samples of the captured animals. Antimicrobial susceptibility test was performed according to the guidelines of Clinical and Laboratory Standards Institute (2014). A total of 329 rat-like animals were captured, including 205 Suncus murinus, 111 Rattus norvegicus, 5 Rattus flavipectus and 8 Mus musculus. The positivity rates of K. pneumoniae and P. aeruginosa were 78.4% and 34.7% in the fecal samples from the captured animals, respectively. K. pneumoniae isolates from Suncus murinus showed a high resistance to ampicillin, cephazolin, nitrofurantoin, piperacillin and cefotaxime (with resistance rates of 100%, 51.2%, 44.2%, 37.2%, and 23.3%, respectively), and K. pneumoniae isolates from Rattus spp. showed a similar drug-resistance profile. The prevalence rates of multidrug resistance and ESBLs were 40.9% and 10.7%, respectively. P. aeruginosa from both Suncus murinus and Rattus spp. exhibited the highest resistance rates to aztreonam (12.4% and 16.0%, respectively), followed by penicillins and fluoroquinolones. P. aeruginosa isolates were susceptible to cephems, aminoglycosides and carbapenems (with resistance rates below 5%). K. pneumoniae and P. aeruginosa isolated from rat-like animals showed drug-resistance profiles similar to those of the strains isolated from clinical patients, suggesting that the possible transmission of K. pneumoniae and P. aeruginosa between rat-like animals and human beings.

  18. Occurrence of co-existing bla VIM-2 and bla NDM-1 in clinical isolates of Pseudomonas aeruginosa from India.

    PubMed

    Paul, Deepjyoti; Dhar, Debadatta; Maurya, Anand Prakash; Mishra, Shweta; Sharma, Gauri Dutt; Chakravarty, Atanu; Bhattacharjee, Amitabha

    2016-05-06

    bla VIM-2 harboring Pseudomonas aeruginosa has been reported worldwide and considered as the most prevalent metallo-β-lactamase after NDM which are found horizontally transferable and mostly associated with integron gene cassettes. The present study investigates the genetic background, transmission dynamics as well as stability of bla VIM-2 in clinical isolates of P. aeruginosa harbor bla NDM-1 as well which were collected from October 2012 to September 2013. Two P. aeruginosa strains harboring bla VIM-2 along with bla NDM-1 were isolated from Silchar Medical College and Hospital, India. Genetic environment of these resistance determinants was determined and transferability was checked by transformation and conjugation assay which was further confirmed by Southern hybridization. Replicon typing was performed to determine the incompatibility group of the resistant plasmid and their stability was checked by serial passage method. Antimicrobial susceptibility pattern of the isolates was determined and their clonal relatedness was checked by pulsed field gel electrophoresis. bla VIM-2 was found to be horizontally transferable through an Inc F type plasmid of approximately 30 kb in size. bla VIM-2 was found to be associated with integron gene cassette and was flanked by two different types of cassette arrays. Both the isolates were co-harboring bla NDM-1 which was carried within Inc N type of plasmid with an approximate 24 kb in size and associated with ISAba125 in their upstream region. Reduced susceptibility rate as well as high MIC range was observed in case of wild strains and transformants carrying bla VIM-2 and bla NDM-1. The detection of this co-existence of multiple carbapenem resistance genes in this part of world is worrisome and further investigation is required in order to trace the source and to initiate proper treatment option.

  19. Antimicrobial resistance, integron carriage, and gyrA and gyrB mutations in Pseudomonas aeruginosa isolated from dogs with otitis externa and pyoderma in Brazil.

    PubMed

    Arais, Lavicie R; Barbosa, André V; Carvalho, Cristiane A; Cerqueira, Aloysio M F

    2016-04-01

    Pseudomonas aeruginosa is associated with otitis and pyoderma in dogs and is frequently resistant to several antimicrobial drugs. Resistance genes can be carried by integrons with quinolone resistance mainly due to mutations in DNA topoisomerases II and IV. To evaluate the antimicrobial susceptibility, integron carriage, and gyrA and gyrB mutations in P. aeruginosa isolates from canine otitis and pyoderma. One hundred and four P. aeruginosa strains isolated from dogs with otitis externa (n = 93) and pyoderma (n = 11). Antimicrobial susceptibility against 16 antibacterial agents was evaluated through agar diffusion tests. Integron carriage, class and gyrA and gyrB mutations were analysed by PCR, restriction fragment length polymorphism (RFLP)-PCR and genetic sequencing assays. Isolates were mostly resistant to enrofloxacin (72.2%) and ticarcillin (59.7%). Lower resistance to ciprofloxacin (7.7%), tobramycin (3.8%) and polymixin B (0.0%) was detected. Ten (9.6%) multidrug-resistant (MDR) strains were detected. Eight (7.7%) strains carried class 1 integrons and this was associated with MDR (three isolates, P ≤ 0.05). Five of the integron-carrying strains exhibited aminoglycoside resistance genes. Mutations of gyrA and gyrB were observed in 10 isolates, seven of them resistant to all fluoroquinolones tested. Enrofloxacin and ticarcilin resistance was widespread in P. aeruginosa isolated from dogs in Brazil. Pseudomonas aeruginosa carrying integrons may present a significant challenge for treatment. © 2016 ESVD and ACVD.

  20. Post-antibiotic effect of orbifloxacin against Escherichia coli and Pseudomonas aeruginosa isolates from dogs.

    PubMed

    Harada, Kazuki; Shimizu, Takae; Kataoka, Yasushi; Takahashi, Toshio

    2012-03-20

    Orbifloxacin is a fluoroquinolone drug used widely in companion animal medicine. In this study, we firstly determined post-antibiotic effects (PAEs) and post-antibiotic sub-minimum inhibitory concentrations (MIC) effects (PA-SMEs) of orbifloxacin for two strains each of Escherichia coli and Pseudomonas aeruginosa from dogs, and these parameters were compared with those of enrofloxacin. At twice the MIC, the PAEs of orbifloxacin ranged from -0.28-0.93 h (mean, 0.29 h) for E. coli and -0.18-1.18 h (mean, 0.37 h) for P. aeruginosa. These parameters were not significantly different for E. coli and shorter for P. aeruginosa, compared to enrofloxacin (P < 0.05). Continued exposure to 0.1, 0.2, and 0.3 the MIC of orbifloxacin resulted in average PA-SMEs of 0.55, 1.11, and 2.03 h, respectively, for E. coli, and 1.04, 1.40, and 2.47 h, respectively, for P. aeruginosa. These PA-SMEs, which had no significant differences with those of enrofloxacin, were significantly longer than the corresponding PAEs (P < 0.05). These results suggest that the PA-SME of orbifloxacin for E. coli and P. aeruginosa can be meaningfully prolonged by increase of sub-MICs.

  1. 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

  2. Effect of Quorum Quenching Lactonase in Clinical Isolates of Pseudomonas aeruginosa and Comparison with Quorum Sensing Inhibitors.

    PubMed

    Guendouze, Assia; Plener, Laure; Bzdrenga, Janek; Jacquet, Pauline; Rémy, Benjamin; Elias, Mikael; Lavigne, Jean-Philippe; Daudé, David; Chabrière, Eric

    2017-01-01

    Pseudomonas aeruginosa is a Gram negative pathogenic bacterium involved in many human infections including otitis, keratitis, pneumonia, and diabetic foot ulcers. P. aeruginosa uses a communication system, referred to as quorum sensing (QS), to adopt a group behavior by synchronizing the expression of certain genes. Among the regulated traits, secretion of proteases or siderophores, motility and biofilm formation are mainly involved in the pathogenicity. Many efforts have been dedicated to the development of quorum sensing inhibitors (QSI) and quorum quenching (QQ) agents to disrupt QS. QQ enzymes have been particularly considered as they may act in a catalytic way without entering the cell. Here we focus on the lactonase SsoPox which was previously investigated for its ability to degrade the signaling molecules, acyl-homoserine lactones, in particular on the engineered variant SsoPox-W263I. We highlight the potential of SsoPox-W263I to inhibit the virulence of 51 clinical P. aeruginosa isolates from diabetic foot ulcers by decreasing the secretion of two virulence factors, proteases and pyocyanin, as well as biofilm formation. We further compared the effect of SsoPox-W263I to the comprehensively described QSI, 5-fluorouracil and C-30. We found the lactonase SsoPox-W263I to be significantly more effective than the tested QSI at their respective concentration optimum and to retain its activity after immobilization steps, paving the way for future therapeutic applications.

  3. Characterization of the Newly Isolated Lytic Bacteriophages KTN6 and KT28 and Their Efficacy against Pseudomonas aeruginosa Biofilm

    PubMed Central

    Danis-Wlodarczyk, Katarzyna; Olszak, Tomasz; Arabski, Michal; Wasik, Slawomir; Majkowska-Skrobek, Grazyna; Augustyniak, Daria; Gula, Grzegorz; Briers, Yves; Jang, Ho Bin; Vandenheuvel, Dieter; Duda, Katarzyna Anna; Lavigne, Rob; Drulis-Kawa, Zuzanna

    2015-01-01

    We here describe two novel lytic phages, KT28 and KTN6, infecting Pseudomonas aeruginosa, isolated from a sewage sample from an irrigated field near Wroclaw, in Poland. Both viruses show characteristic features of Pbunalikevirus genus within the Myoviridae family with respect to shape and size of head/tail, as well as LPS host receptor recognition. Genome analysis confirmed the similarity to other PB1-related phages, ranging between 48 and 96%. Pseudomonas phage KT28 has a genome size of 66,381 bp and KTN6 of 65,994 bp. The latent period, burst size, stability and host range was determined for both viruses under standard laboratory conditions. Biofilm eradication efficacy was tested on peg-lid plate assay and PET membrane surface. Significant reduction of colony forming units was observed (70-90%) in 24 h to 72 h old Pseudomonas aeruginosa PAO1 biofilm cultures for both phages. Furthermore, a pyocyanin and pyoverdin reduction tests reveal that tested phages lowers the amount of both secreted dyes in 48-72 h old biofilms. Diffusion and goniometry experiments revealed the increase of diffusion rate through the biofilm matrix after phage application. These characteristics indicate these phages could be used to prevent Pseudomonas aeruginosa infections and biofilm formation. It was also shown, that PB1-related phage treatment of biofilm caused the emergence of stable phage-resistant mutants growing as small colony variants. PMID:25996839

  4. Effect of Quorum Quenching Lactonase in Clinical Isolates of Pseudomonas aeruginosa and Comparison with Quorum Sensing Inhibitors

    PubMed Central

    Guendouze, Assia; Plener, Laure; Bzdrenga, Janek; Jacquet, Pauline; Rémy, Benjamin; Elias, Mikael; Lavigne, Jean-Philippe; Daudé, David; Chabrière, Eric

    2017-01-01

    Pseudomonas aeruginosa is a Gram negative pathogenic bacterium involved in many human infections including otitis, keratitis, pneumonia, and diabetic foot ulcers. P. aeruginosa uses a communication system, referred to as quorum sensing (QS), to adopt a group behavior by synchronizing the expression of certain genes. Among the regulated traits, secretion of proteases or siderophores, motility and biofilm formation are mainly involved in the pathogenicity. Many efforts have been dedicated to the development of quorum sensing inhibitors (QSI) and quorum quenching (QQ) agents to disrupt QS. QQ enzymes have been particularly considered as they may act in a catalytic way without entering the cell. Here we focus on the lactonase SsoPox which was previously investigated for its ability to degrade the signaling molecules, acyl-homoserine lactones, in particular on the engineered variant SsoPox-W263I. We highlight the potential of SsoPox-W263I to inhibit the virulence of 51 clinical P. aeruginosa isolates from diabetic foot ulcers by decreasing the secretion of two virulence factors, proteases and pyocyanin, as well as biofilm formation. We further compared the effect of SsoPox-W263I to the comprehensively described QSI, 5-fluorouracil and C-30. We found the lactonase SsoPox-W263I to be significantly more effective than the tested QSI at their respective concentration optimum and to retain its activity after immobilization steps, paving the way for future therapeutic applications. PMID:28261183

  5. Removal of toxic Co-EDTA complex by a halophilic solar-salt-pan isolate Pseudomonas aeruginosa SPB-1.

    PubMed

    Paraneeiswaran, A; Shukla, Sudhir K; Subba Rao, T; Prashanth, K

    2014-01-01

    In this study, a promising bioremediation approach was developed to remove [Co(III)-EDTA](-) complex that is generated during the waste management process. Though several studies have been reported on bioremediation of cobalt, the removal of [Co(III)-EDTA](-) complex has not been tested. A [Co(III)-EDTA](-) resistant bacterium, Pseudomonas aeruginosa SPB-1 was isolated from the solar-salt-pan and physical parameters were optimized for its growth. The various studies showed that the removal of [Co(III)-EDTA](-) from the bulk liquid was due to the adsorption of the complex by the biomass. Using absorption/desorption isotherm over a range of pH (1-8), the maximum adsorption of [Co(III)-EDTA](-) was found to be at pH 7.0 and maximum desorption from the biomass occurred at pH 1.0, thus rendering an ion exchange property to P. aeruginosa SPB-1 biomass. P. aeruginosa SPB-1 biomass could be used as bio-resin that showed 80.4±3.27% adsorption capacity up to fourth cycle and the biomass was viable till the ninth cycle with 10.5±7.3% adsorption. Radiation tolerance potential i.e. D10 value for the strain was found to be ~300 Gy, which suggests the potential use of the bacterium in bioremediation of moderately active nuclear waste. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Characterization of the Newly Isolated Lytic Bacteriophages KTN6 and KT28 and Their Efficacy against Pseudomonas aeruginosa Biofilm.

    PubMed

    Danis-Wlodarczyk, Katarzyna; Olszak, Tomasz; Arabski, Michal; Wasik, Slawomir; Majkowska-Skrobek, Grazyna; Augustyniak, Daria; Gula, Grzegorz; Briers, Yves; Jang, Ho Bin; Vandenheuvel, Dieter; Duda, Katarzyna Anna; Lavigne, Rob; Drulis-Kawa, Zuzanna

    2015-01-01

    We here describe two novel lytic phages, KT28 and KTN6, infecting Pseudomonas aeruginosa, isolated from a sewage sample from an irrigated field near Wroclaw, in Poland. Both viruses show characteristic features of Pbunalikevirus genus within the Myoviridae family with respect to shape and size of head/tail, as well as LPS host receptor recognition. Genome analysis confirmed the similarity to other PB1-related phages, ranging between 48 and 96%. Pseudomonas phage KT28 has a genome size of 66,381 bp and KTN6 of 65,994 bp. The latent period, burst size, stability and host range was determined for both viruses under standard laboratory conditions. Biofilm eradication efficacy was tested on peg-lid plate assay and PET membrane surface. Significant reduction of colony forming units was observed (70-90%) in 24 h to 72 h old Pseudomonas aeruginosa PAO1 biofilm cultures for both phages. Furthermore, a pyocyanin and pyoverdin reduction tests reveal that tested phages lowers the amount of both secreted dyes in 48-72 h old biofilms. Diffusion and goniometry experiments revealed the increase of diffusion rate through the biofilm matrix after phage application. These characteristics indicate these phages could be used to prevent Pseudomonas aeruginosa infections and biofilm formation. It was also shown, that PB1-related phage treatment of biofilm caused the emergence of stable phage-resistant mutants growing as small colony variants.

  7. [Epidemiological profile and antibiotic susceptibility of Pseudomonas aeruginosa isolates within the burned patient hospitalized in the intensive care burn unit].

    PubMed

    Lamia, Thabet; Bousselmi, K; Saida, Ben Redjeb; Allah, Messadi Amen

    2007-02-01

    Pseudomonas aeruginosa plays a predominant role as an etiological agent involved in serious infections in burned patients. Treatment of these infections is frequently complicated by antibiotic resistance, a problem that is is increasing in recent years. The objective of this study is to analyze epidemiological profile and antibiotic susceptibility of P. aeruginosa isolates within the burned patients admitted in our intensive care department. During a period of 4 years (2000/2003), 828 burn patients were admitted. The survey of antibiotic susceptibility of P. aeruginosa showed high percentages of resistance to the different antibiotics. 60.9% of strains were resistant to piperacillin, 53.4% to ceftazidime, 37.6% to imipenem, 70.6% to cefsulodine, 59.3% to tobramycin, 80% to gentamicin, 62.4% to amikacin and 53.4% to ciprofloxacin. It is necessary to implement urgent measures to prevent the spreading of this multiresistant strain. These measures include: sensible limitation of the use of antimicrobial agent, strict disinfection and hygienic procedures.

  8. Two Novel Class I Integron Arrays Containing IMP-18 Metallo-β-Lactamase Gene in Pseudomonas aeruginosa Clinical Isolates from Puerto Rico

    PubMed Central

    Martínez, T.; Vazquez, G. J.; Aquino, E. E.; Goering, R. V.

    2012-01-01

    During a β-lactam resistance surveillance study, 12 IMP-18-positive Pseudomonas aeruginosa isolates belonging to 9 different pulsed-field gel electrophoresis groups were identified. In nine isolates, a class I integron with a novel gene array was identified that contained blaIMP-18 and blaOXA-224, while in two isolates the class I integron contained blaIMP-18 and blaOXA-2 but in a new arrangement. Our findings show the dissemination of two novel class I integrons in P. aeruginosa from different regions of Puerto Rico. PMID:22290962

  9. Isolation and characterization of Pseudomonas aeruginosa strain SJTD-2 for degrading long-chain n-alkanes and crude oil.

    PubMed

    Xu, Jing; Liu, Huan; Liu, Jianhua; Liang, Rubing

    2015-06-04

    Oil pollution poses a severe threat to ecosystems, and bioremediation is considered as a safe and efficient alternative to physicochemical. for eliminating this contaminant. In this study, a gram-negative bacteria strain SJTD-2 isolated from oil-contaminated soil was found capable of utilizing n-alkanes and crude oil as sole energy sources. The efficiency of this strain in degrading these pollutants was analyzed. Strain SJTD-2 was identified on the basis of its phenotype, its physiological features, and a comparative genetic analysis using 16S rRNA sequence. Growth of strain SJTD-2 with different carbon sources (n-alkanes of different lengths and crude oil) was assessed, and the gas chromatography-mass spectrometry method was used to analyze the degradation efficiency of strain SJTD-2 for n-alkanes and petroleum by detecting the residual n-alkane concentrations. Strain SJTD-2 was identified as Pseudomonas aeruginosa based on the phenotype, physiological features, and 16S rRNA sequence analysis. This strain can efficiently decompose medium-chain and long-chain n-alkanes (C10-C26), and petroleum as its sole carbon sources. It preferred the long-chain n-alkanes (C18-C22), and n-docosane was considered as the best carbon source for its growth. In 48 h, 500 mg/L n-docosane could be degraded completely, and 2 g/L n-docosane was decomposed to undetectable levels within 72 h. Moreover, strain SJTD-2 could utilize about 88% of 2 g/L crude oil in 7days. Compared with other alkane-utilizing strains, strain SJTD-2 showed outstanding degradation efficiency for long-chain n-alkanes and high tolerance to petroleum at elevated concentrations. The isolation and characterization of strain SJTD-2 would help researchers study the mechanisms underlying the biodegradation of n-alkanes, and this strain could be used as a potential strain for environmental governance and soil bioremediation.

  10. Biosorption of chromium, copper, manganese and zinc by Pseudomonas aeruginosa AT18 isolated from a site contaminated with petroleum.

    PubMed

    Pérez Silva, Rosa María; Abalos Rodríguez, Arelis; Gómez Montes De Oca, José Manuel; Cantero Moreno, Domingo

    2009-02-01

    The study describes the sorption of Cr, Cu, Mn and Zn by Pseudomonas aeruginosa AT18 isolated from a site contaminated with petroleum and heavy metals. The concentrations studied were 50, 49, 60 and 70 (mg L(-1)) for Cr, Cu, Mn and Zn, respectively. The solution pH and ionic strength were very important factors in the metal biosorption performance and the biosorption capacity of P. aeruginosa AT18 for Cr3+,Cu2+, Mn2+ and Zn2+. In aqueous solution, the biosorption increased with increasing pH in the range 5.46-7.72. The results obtained in the experimental assays show that P. aeruginosa AT18 has the capacity for biosorption of the metallic ions Cr3+, Cu2+ and Zn2+ in solutions, although its capacity for the sorption of manganese is low (22.39 mg Mn2+/g of biomass) in comparison to the Cr3+, Cu2+ and Zn2+ ions, as shown by the individual analyses. However, 20% of the manganese was removed from an initial concentration of 49.0 mg L(-1), with a Qm value similar to that obtained in solutions containing mixtures of Cr3+, Cu2+, Mn2+and Zn2+. The chromium level sorbed by P. aeruginosa AT18 biomass was higher than that for Cu, Mn and Zn, with 100% removal in the pH range 7.00-7.72 and a Qm of 121.90-200.00 mg of Cr3+/g of biomass. The removal of Cr, Cu and Zn is also a result of precipitation processes.

  11. 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

  12. Antibiotic resistance and population structure of cystic fibrosis Pseudomonas aeruginosa isolates from a Spanish multi-centre study.

    PubMed

    López-Causapé, Carla; de Dios-Caballero, Juan; Cobo, Marta; Escribano, Amparo; Asensio, Óscar; Oliver, Antonio; Del Campo, Rosa; Cantón, Rafael; Solé, Amparó; Cortell, Isidoro; Asensio, Oscar; García, Gloria; Martínez, María Teresa; Cols, María; Salcedo, Antonio; Vázquez, Carlos; Baranda, Félix; Girón, Rosa; Quintana, Esther; Delgado, Isabel; de Miguel, María Ángeles; García, Marta; Oliva, Concepción; Prados, María Concepción; Barrio, María Isabel; Pastor, María Dolores; Olveira, Casilda; de Gracia, Javier; Álvarez, Antonio; Escribano, Amparo; Castillo, Silvia; Figuerola, Joan; Togores, Bernat; Oliver, Antonio; López, Carla; de Dios Caballero, Juan; Tato, Marta; Máiz, Luis; Suárez, Lucrecia; Cantón, Rafael

    2017-09-01

    The first Spanish multi-centre study on the microbiology of cystic fibrosis (CF) was conducted from 2013 to 2014. The study involved 24 CF units from 17 hospitals, and recruited 341 patients. The aim of this study was to characterise Pseudomonas aeruginosa isolates, 79 of which were recovered from 75 (22%) patients. The study determined the population structure, antibiotic susceptibility profile and genetic background of the strains. Fifty-five percent of the isolates were multi-drug-resistant, and 16% were extensively-drug-resistant. Defective mutS and mutL genes were observed in mutator isolates (15.2%). Considerable genetic diversity was observed by pulsed-field gel electrophoresis (70 patterns) and multi-locus sequence typing (72 sequence types). International epidemic clones were not detected. Fifty-one new and 14 previously described array tube (AT) genotypes were detected by AT technology. This study found a genetically unrelated and highly diverse CF P. aeruginosa population in Spain, not represented by the epidemic clones widely distributed across Europe, with multiple combinations of virulence factors and high antimicrobial resistance rates (except for colistin). Copyright © 2017 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

  13. Changing susceptibility of Pseudomonas aeruginosa isolates from cystic fibrosis patients with the clinical use of newer antibiotics.

    PubMed Central

    Bosso, J A; Allen, J E; Matsen, J M

    1989-01-01

    To detect a change in antibiotic susceptibility patterns in Pseudomonas aeruginosa isolates upon the introduction and clinical use of ciprofloxacin, aztreonam, and ceftazidime, MICs for clinical isolates collected before introduction of the antibiotics, during early clinical use, and later were determined for these and seven other antipseudomonal antibiotics. Concomitant resistance to two or more antibiotics was also studied. Over the three study periods, rates of susceptibility to 9 of the 10 antibiotics decreased. The largest decrease occurred with ceftazidime. Analysis of subsets of isolates from patients treated with ciprofloxacin or aztreonam also showed declining susceptibility to the latter but a stabilization of susceptibility to the former after an initial decline. Concomitant resistance within and among antibiotic classes was common. PMID:2499252

  14. Genes required for and effects of alginate overproduction induced by growth of Pseudomonas aeruginosa on Pseudomonas isolation agar supplemented with ammonium metavanadate.

    PubMed

    Damron, F Heath; Barbier, Mariette; McKenney, Elizabeth S; Schurr, Michael J; Goldberg, Joanna B

    2013-09-01

    Pseudomonas aeruginosa is an opportunistic pathogen that can adapt to changing environments and can secrete an exopolysaccharide known as alginate as a protection response, resulting in a colony morphology and phenotype referred to as mucoid. However, how P. aeruginosa senses its environment and activates alginate overproduction is not fully understood. Previously, we showed that Pseudomonas isolation agar supplemented with ammonium metavanadate (PIAAMV) induces P. aeruginosa to overproduce alginate. Vanadate is a phosphate mimic and causes protein misfolding by disruption of disulfide bonds. Here we used PIAAMV to characterize the pathways involved in inducible alginate production and tested the global effects of P. aeruginosa growth on PIAAMV by a mutant library screen, by transcriptomics, and in a murine acute virulence model. The PA14 nonredundant mutant library was screened on PIAAMV to identify new genes that are required for the inducible alginate stress response. A functionally diverse set of genes encoding products involved in cell envelope biogenesis, peptidoglycan remodeling, uptake of phosphate and iron, phenazine biosynthesis, and other processes were identified as positive regulators of the mucoid phenotype on PIAAMV. Transcriptome analysis of P. aeruginosa cultures growing in the presence of vanadate showed differential expression of genes involved in virulence, envelope biogenesis, and cell stress pathways. In this study, it was observed that growth on PIAAMV attenuates P. aeruginosa in a mouse pneumonia model. Induction of alginate overproduction occurs as a stress response to protect P. aeruginosa, but it may be possible to modulate and inhibit these pathways based on the new genes identified in this study.

  15. Rhamnolipid production with indigenous Pseudomonas aeruginosa EM1 isolated from oil-contaminated site.

    PubMed

    Wu, Jane-Yii; Yeh, Kuei-Ling; Lu, Wei-Bin; Lin, Chung-Liang; Chang, Jo-Shu

    2008-03-01

    Rhamnolipid is one of the most effective and commonly used biosurfactant with wide industrial applications. Systematic strategies were applied to improve rhamnolipid (RL) production with a newly isolated indigenous strain Pseudomonas aeruginosa EM1 originating from an oil-contaminated site located in southern Taiwan. Seven carbon substrates and four nitrogen sources were examined for their effects on RL production. In addition, the effect of carbon to nitrogen (C/N) ratio on RL production was also studied. Single-factor experiments show that the most favorable carbon sources for RL production were glucose and glycerol (both at 40 g/L), giving a RL yield of 7.5 and 4.9 g/L, respectively. Meanwhile, sodium nitrate appeared to be the preferable nitrogen source, resulting in a RL production of 8.6g/L. Using NaNO(3) as the nitrogen source, an optimal C/N ratio of 26 and 52 was obtained for glucose- and glycerol-based culture, respectively. To further optimize the composition of fermentation medium, twenty experiments were designed by response surface methodology (RSM) to explore the favorable concentration of three critical components in the medium (i.e., glucose, glycerol, and NaNO(3)). The RSM analysis gave an optimal concentration of 30.5, 18.1, and 4.9 g/L for glucose, glycerol, and NaNO(3), respectively, predicting a maximum RL yield of 12.6 g/L, which is 47% higher than the best yield (8.6 g/L) obtained from preliminary selection tests and single factor experiments (glucose and NaNO(3) as the carbon and nitrogen source). The NMR and mass spectrometry analysis show that the purified RL product contained L-rhamnosyl-beta-hydroxydecanoyl-beta-hydroxydecanoate (RL1) and L-rhamnosyl L-rhamnosyl-beta-hydroxydecanoyl-beta-hydroxydecanoate (RL2). Meanwhile, HPLC analysis indicates that the molar ratio of RL1 and RL2 in the purified rhamnolipid product was ca. 1:1.

  16. Surveillance for Antimicrobial Susceptibility among Clinical Isolates of Pseudomonas aeruginosa and Acinetobacter baumannii from Hospitalized Patients in the United States, 1998 to 2001

    PubMed Central

    Karlowsky, James A.; Draghi, Deborah C.; Jones, Mark E.; Thornsberry, Clyde; Friedland, Ian R.; Sahm, Daniel F.

    2003-01-01

    Pseudomonas aeruginosa and Acinetobacter baumannii are the most prevalent nonfermentative bacterial species isolated from clinical specimens of hospitalized patients. A surveillance study of 65 laboratories in the United States from 1998 to 2001 found >90% of isolates of P. aeruginosa from hospitalized patients to be susceptible to amikacin and piperacillin-tazobactam; 80 to 90% of isolates to be susceptible to cefepime, ceftazidime, imipenem, and meropenem; and 70 to 80% of isolates to be susceptible to ciprofloxacin, gentamicin, levofloxacin, and ticarcillin-clavulanate. From 1998 to 2001, decreases in antimicrobial susceptibility (percents) among non-intensive-care-unit (non-ICU) inpatients and ICU patients, respectively, were greatest for ciprofloxacin (6.1 and 6.5), levofloxacin (6.6 and 3.5), and ceftazidime (4.8 and 3.3). Combined 1998 to 2001 results for A. baumannii isolated from non-ICU inpatients and ICU patients, respectively, demonstrated that >90% of isolates tested were susceptible to imipenem (96.5 and 96.6%) and meropenem (91.6 and 91.7%); fewer isolates from both non-ICU inpatients and ICU patients were susceptible to amikacin and ticarcillin-clavulanate (70 to 80% susceptible); and <60% of isolates were susceptible to ceftazidime, ciprofloxacin, gentamicin, or levofloxacin. From 1998 to 2001, rates of multidrug resistance (resistance to at least three of the drugs ceftazidime, ciprofloxacin, gentamicin, and imipenem) showed small increases among P. aeruginosa strains isolated from non-ICU inpatients (5.5 to 7.0%) and ICU patients (7.4 to 9.1%). From 1998 to 2001, rates of multidrug resistance among A. baumannii strains isolated from non-ICU inpatients (27.6 to 32.5%) and ICU patients (11.6 to 24.2%) were higher and more variable than those observed for P. aeruginosa. Isolates concurrently susceptible, intermediate, or resistant to both imipenem and meropenem accounted for 89.8 and 91.2% of P. aeruginosa and A. baumannii isolates, respectively

  17. Presence of exoY, exoS, exoU and exoT genes, antibiotic resistance and biofilm production among Pseudomonas aeruginosa isolates in Northwest Iran.

    PubMed

    Azimi, Somayeh; Kafil, Hossein Samadi; Baghi, Hossein Bannazadeh; Shokrian, Saeed; Najaf, Khadijeh; Asgharzadeh, Mohammad; Yousefi, Mehdi; Shahrivar, Firooz; Aghazadeh, Mohammad

    2016-01-01

    Hintergrund:Pseudomonas aeruginosa, ein Gram-negatives Stäbchenbakterium, besitzt eine wichtige Rolle als Krankheitserreger. Daher untersuchten wir Pseudomonas aeruginosa-Isolate im Nordwestiran auf das Vorkommen von exo-Genen und Biofilmbildnern. Material und Methode: 160 P. aeruginosa-Isolate wurden biochemisch identifiziert und die Antibiotikaresistenz charakterisiert. Die Fähigkeit zur Biofilmbildung wurde im Mikrotiterplatten-Assay, das Vorkommen von exo-Genen mit Allel-spezifischer PCR (Polymerase-Kettenreaktion) analysiert. Zur statistischen Analyse wurde der Chi-Quadrat-Test eingesetzt.Ergebnisse: Als effektivste Antibiotika erwiesen sich Colistin und Polymyxin B. 87% der Isolate waren Biofilmbildner, davon 69% mit massiver Biofilmbildung. In 55% der Isolate wurden exoY, in 52% exoU, in 26,3% exoS und in 5% exoT nachgewiesen. Schlussfolgerung: Die Analyse ergab eine unterschiedliche Verteilung der exo-Gene bei klinischen Isolaten von P. aeruginosa im Nordwestiran. ExoS und exoU kamen häufiger bei nicht biofilmbildenen Isolaten, exoY häufiger bei Biofilmbildnern vor. Die Ergebnisse können ein Hinweis auf die Bedeutung von exoY bei Biofilm bildenden Pseudomonas aeruginosa-Isolaten sein.

  18. Effect of Shear Stress on Pseudomonas aeruginosa Isolated from the Cystic Fibrosis Lung

    PubMed Central

    Dingemans, Jozef; Monsieurs, Pieter; Yu, Sung-Huan; Crabbé, Aurélie; Förstner, Konrad U.; Malfroot, Anne

    2016-01-01

    ABSTRACT Chronic colonization of the lungs by Pseudomonas aeruginosa is one of the major causes of morbidity and mortality in cystic fibrosis (CF) patients. To gain insights into the characteristic biofilm phenotype of P. aeruginosa in the CF lungs, mimicking the CF lung environment is critical. We previously showed that growth of the non-CF-adapted P. aeruginosa PAO1 strain in a rotating wall vessel, a device that simulates the low fluid shear (LS) conditions present in the CF lung, leads to the formation of in-suspension, self-aggregating biofilms. In the present study, we determined the phenotypic and transcriptomic changes associated with the growth of a highly adapted, transmissible P. aeruginosa CF strain in artificial sputum medium under LS conditions. Robust self-aggregating biofilms were observed only under LS conditions. Growth under LS conditions resulted in the upregulation of genes involved in stress response, alginate biosynthesis, denitrification, glycine betaine biosynthesis, glycerol metabolism, and cell shape maintenance, while genes involved in phenazine biosynthesis, type VI secretion, and multidrug efflux were downregulated. In addition, a number of small RNAs appeared to be involved in the response to shear stress. Finally, quorum sensing was found to be slightly but significantly affected by shear stress, resulting in higher production of autoinducer molecules during growth under high fluid shear (HS) conditions. In summary, our study revealed a way to modulate the behavior of a highly adapted P. aeruginosa CF strain by means of introducing shear stress, driving it from a biofilm lifestyle to a more planktonic lifestyle. PMID:27486191

  19. In169, a new class 1 integron that encoded bla(IMP-18) in a multidrug-resistant Pseudomonas aeruginosa isolate from Mexico.

    PubMed

    Sánchez-Martinez, Guillermina; Garza-Ramos, Ulises Jesús; Reyna-Flores, Fernando Luis; Gaytán-Martínez, Jesús; Lorenzo-Bautista, Isaí Guillermo; Silva-Sanchez, Jesús

    2010-05-01

    Carbapenem resistance in Pseudomonas aeruginosa may be due to the presence of metallo-beta-lactamases (MbetaL). The genes that encode these enzymes can be located in association with aminoglycoside-modifying enzymes on class 1 integrons. This study describes the bla(IMP-18) class 1 integron array (In169) from a carbapenem-resistant P. aeruginosa clinical isolate obtained at the Centro Medico Nacional La Raza (CMNR) in Mexico City and compares it to other bla(IMP)-type producers. Twenty six multiresistant P. aeruginosa clinical isolates were recovered between June and December 2004 and tested by MicroScan and CLSI agar dilution methods. The MbetaL production was screened by a disk approximation test and MbetaL Etest strips, whereas MbetaL genes and integrons were detected using PCR primers. DNA sequence analysis was carried out by BLAST, and epidemiological typing was performed by pulsed-field gel electrophoresis (PFGE). A Southern hybridization analysis was performed with a bla(IMP) specific DNA probe. Nine of 26 P. aeruginosa isolates were imipenem-resistant with unique PFGE patterns (no clonal relation), and only one strain (5106) was positive for MbetaL production, corresponding to the IMP-type. The class 1 integron encoding the MbetaL was characterized: it contained the IMP-18, two copies of aadA2 and OXA-2 genes, corresponding to a new class 1 integron array, denoted In169. P. aeruginosa isolate 5106 is genetically related to bla(IMP-18) positive P. aeruginosa isolate from a distant hospital (Hospital Infantil de Morelia). This report is the first to describe the bla(IMP-18) in two genetically related isolates from two different institutions. Copyright 2010 IMSS. Published by Elsevier Inc. All rights reserved.

  20. Unraveling genomic and phenotypic nature of multidrug-resistant (MDR) Pseudomonas aeruginosa VRFPA04 isolated from keratitis patient.

    PubMed

    N, Murugan; J, Malathi; V, Umashankar; H N, Madhavan

    2016-12-01

    Multidrug-resistant (MDR) Pseudomonas aeruginosa VRFPA04, obtained from a keratitis patient was found to exhibit resistance to betalactam (Penicillins, cephalosporins, including carbapenems, except aztreonam), aminoglycosides, quinolone group of drugs and susceptible to colistin. The complete genome sequencing of the ocular isolate to measure and ascertain the degree of multidrug resistance in VRFPA04 strain resulted in 6,818,030bp (6.8Mb) genome sizes, which happen to be the third largest genome available in the Genbank to date. Two chromosomally integrated class I integrons carrying blaVIM-2 carbapenemase gene, multiple secretory systems consisting of types I-VI and VIII proteins and ocular virulence factors exo-T, Y, U and exotoxin A, a gene that inhibits protein synthesis which could have caused corneal cell death and Phytohormone auxin biosynthetic protein were detected in the genome of VRFPA04 Genome. In addition, 58 Regions of Genomic Plasticity (RGPs) regions, multiple phage genomes, genomic islands, CRISPR genes and RND family efflux pumps, such as MexCD-OprJ and MexEF-OprN and its regulators, MexT and MexR, were unraveled in VRFPA04. Thus, the current study reveals the virulence factors and resistome nature of an ocular isolate P aeruginosa VRFPA04 genome. Copyright © 2016 Elsevier GmbH. All rights reserved.

  1. A wound-isolated Pseudomonas aeruginosa grows a biofilm in vitro within 10 hours and is visualized by light microscopy.

    PubMed

    Harrison-Balestra, Catherine; Cazzaniga, Alejandro L; Davis, Stephen C; Mertz, Patricia M

    2003-06-01

    In chronic wounds, biofilms probably play a vital role in protecting bacteria from host defenses and antimicrobial medications by creating a barrier of exopolysaccharide that is difficult for the immune system and antibiotics to penetrate. A biofilm consists of an exopolysaccharide matrix that is produced and secreted by certain species of bacteria. The purpose of this study was to visualize and time the progressing growth of a biofilm by a wound-isolated Pseudomonas aeruginosa. P. aeruginosa that was initially isolated from a human burn wound was allowed to grow a biofilm in vitro. We used a modified Congo red staining technique to demonstrate the sequential development of a mature biofilm as examined by light microscopy. We show that the exopolysaccharide of the developing biofilm is visible in just 5 hours after inoculation and has the characteristics of a mature biofilm by 10 hours. The rapidity of biofilm growth suggests that bacteria in wounds possess the capacity of producing this shield against antibiotics and immune effector cells early in the infection process. Therefore, efforts to prevent or slow the proliferation of bacteria and biofilms should occur soon after a wound is created. Additionally, this staining technique can be used to demonstrate the ability of agents to slow biofilm growth or to interrupt formed biofilm and may be useful in future studies of chronically infected wounds.

  2. Biofilm formation and cellulose expression among diverse environmental Pseudomonas isolates.

    PubMed

    Ude, Susanne; Arnold, Dawn L; Moon, Christina D; Timms-Wilson, Tracey; Spiers, Andrew J

    2006-11-01

    The ability to form biofilms is seen as an increasingly important colonization strategy among both pathogenic and environmental bacteria. A survey of 185 plant-associated, phytopathogenic, soil and river Pseudomonas isolates resulted in 76% producing biofilms at the air-liquid (A-L) interface after selection in static microcosms. Considerable variation in biofilm phenotype was observed, including waxy aggregations, viscous and floccular masses, and physically cohesive biofilms with continuously varying strengths over 1500-fold. Calcofluor epifluorescent microscopy identified cellulose as the matrix component in biofilms produced by Pseudomonas asplenii, Pseudomonas corrugata, Pseudomonas fluorescens, Pseudomonas marginalis, Pseudomonas putida, Pseudomonas savastanoi and Pseudomonas syringae isolates. Cellulose expression and biofilm formation could be induced by the constitutively active WspR19 mutant of the cyclic-di-GMP-associated, GGDEF domain-containing response regulator involved in the P. fluorescens SBW25 wrinkly spreader phenotype and cellular aggregation in Pseudomonas aeruginosa PA01. WspR19 could also induce P. putida KT2440, which otherwise did not produce a biofilm or express cellulose, as well as Escherichia coli K12 and Salmonella typhimurium LT2, both of which express cellulose yet lack WspR homologues. Statistical analysis of biofilm parameters suggest that biofilm development is a more complex process than that simply described by the production of attachment and matrix components and bacterial growth. This complexity was also seen in multivariate analysis as a species-ecological habitat effect, underscoring the fact that in vitro biofilms are abstractions of those surface and volume colonization processes used by bacteria in their natural environments.

  3. Evaluation of the E Test for Antimicrobial Susceptibility Testing of Pseudomonas aeruginosa Isolates from Patients with Long-Term Bladder Catheterization

    PubMed Central

    Di Bonaventura, Giovanni; Ricci, Evandro; Della Loggia, Nicoletta; Catamo, Giovanni; Piccolomini, Raffaele

    1998-01-01

    The E test was evaluated in comparison with reference agar methods (National Committee for Clinical Laboratory Standards) for the susceptibility testing of 248 Pseudomonas aeruginosa isolates from bladder-catheterized patients against nine antibiotics. The E-test MICs correlated well with those determined by the agar dilution and disk diffusion reference methods (88 and 92.5% within 1 log2 dilution step, respectively), confirming that the E test is a reliable method for the determination of MICs of antibiotics for catheterization-associated P. aeruginosa isolates. PMID:9508323

  4. Performance of Vitek 2 in Antimicrobial Susceptibility Testing of Pseudomonas aeruginosa Isolates with Different Mechanisms of β-Lactam Resistance▿

    PubMed Central

    Mazzariol, Annarita; Aldegheri, Marco; Ligozzi, Marco; Lo Cascio, Giuliana; Koncan, Raffaella; Fontana, Roberta

    2008-01-01

    A total of 78 isolates of Pseudomonas aeruginosa grouped according to the phenotype for ceftazidime and imipenem susceptibility/resistance were used to assess the accuracy of the Vitek 2 system in antimicrobial susceptibility testing. Comparisons were made with a MIC gradient test for piperacillin-tazobactam, ceftazidime, aztreonam, imipenem, meropenem, gentamicin, and ciprofloxacin. For the total of 546 isolate-antimicrobial combinations tested, the category agreement was 83.6%, with 2.0, 1.6, and 12.8% very major, major, and minor errors, respectively. Vitek 2 accuracy was influenced differently by the mechanism responsible for resistance, and interpretation of the results in relation to phenotype could improve the performance of the system. PMID:18434562

  5. Isolation and characterization of a Pseudomonas aeruginosa from a virgin Brazilian Amazon region with potential to degrade atrazine.

    PubMed

    Fernandes, Ana Flavia Tonelli; da Silva, Michelle Barbosa Partata; Martins, Vinicius Vicente; Miranda, Carlos Eduardo Saraiva; Stehling, Eliana Guedes

    2014-12-01

    The use of pesticides to increase agricultural production can result in the contamination of the environment, causing changes in the genetic structure of organisms and in the loss of biodiversity. This practice is also inducing changes in the rainforest ecosystem. In this work, a Pseudomonas aeruginosa isolated from a preservation soil area of the Brazilian Amazon Forest, without usage of any pesticide, was evaluated for its potential to degrade atrazine. This isolate presented all responsible genes (atzA, atzB, atzC, atzD, atzE, and atzF) for atrazine mineralization and demonstrated capacity to use atrazine as a nitrogen source, having achieved a reduction of 44 % of the initial concentration of atrazine after 24 h. These results confirm gene dispersion and/or a possible contamination of the area with the herbicide, which reinforces global concern of the increase and intensive use of pesticides worldwide.

  6. Characterization of mechanisms of quinolone resistance in Pseudomonas aeruginosa strains isolated in vitro and in vivo during experimental endocarditis.

    PubMed Central

    Chamberland, S; Bayer, A S; Schollaardt, T; Wong, S A; Bryan, L E

    1989-01-01

    Mechanisms of resistance to quinolones were characterized in Pseudomonas aeruginosa strains isolated after Tn5 insertional mutagenesis and in resistant strains that emerged during pefloxacin therapy of experimental aortic endocarditis. Quinolone resistance achieved in in vitro-selected mutants Qr-1 and Qr-2 was associated with cross-resistance to several groups of antimicrobial agents, including beta-lactams, tetracycline, and chloramphenicol. A significant reduction of norfloxacin uptake was also observed. After ether permeabilization of the cells, DNA synthesis of these two isolates was as susceptible to norfloxacin as DNA synthesis of the parent strain (PAO1). These results indicate that alteration of outer membrane permeability is the primary determinant of resistance in these isolates. This altered cell permeability was correlated with reduction of outer membrane protein G (25.5 kilodaltons) and loss of a 40-kilodalton outer membrane protein in strain Qr-1. Resistance to quinolones that emerged during experimental endocarditis therapy was associated with both modification of outer membrane permeability (decreased uptake of norfloxacin) and decreased susceptibility of DNA synthesis to norfloxacin. Resistance was limited to quinolones and chloramphenicol. For these strains, norfloxacin inhibitory doses (50%) for DNA synthesis were identical to the drug MICs, suggesting that despite the identification of a permeability change, perhaps due to changes of lipopolysaccharide, the alteration of the quinolone intracellular target(s) susceptibility constitutes the primary determinant of resistance. Also, two distinct levels of norfloxacin resistance of DNA synthesis were found in these isolates, indicating that at least two distinct alterations of the drug target(s) are possible in P. aeruginosa. Images PMID:2502066

  7. 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

  8. Waste Isolation Pilot Plant Environmental Monitoring Plan

    SciTech Connect

    Westinghouse Electric Company Waste Isolation Division

    1999-09-29

    DOE Order 5400.1, General Environmental Protection Program Requirements (DOE, 1990a), requires each DOE facility to prepare an EMP. This document is prepared for WIPP in accordance with the guidance contained in DOE Order 5400.1; DOE Order 5400.5, Radiation Protection of the Public and Environment (DOE, 1990b); Environmental Regulatory Guide for Radiological Effluent Monitoring and Environmental Surveillance (DOE/EH-0173T; DOE, 1991); and the Title 10 Code of Federal Regulations (CFR) 834, Radiation Protection of the Public and Environment (Draft). Many sections of DOE Order 5400.1 have been replaced by DOE Order 231.1 (DOE, 1995), which is the driver for the Annual Site Environmental Report (ASER) and the guidance source for preparing many environmental program documents. The WIPP project is operated by Westinghouse Electric Company, Waste Isolation Division (WID), for the DOE. This plan defines the extent and scope of the WIPP's effluent and environmental monitoring programs during the facility's operational life and also discusses the WIPP's quality assurance/quality control (QA/QC) program as it relates to environmental monitoring. In addition, this plan provides a comprehensive description of environmental activities at WIPP including: A summary of environmental programs, including the status of environmental monitoring activities A description of the WIPP project and its mission A description of the local environment, including demographics An overview of the methodology used to assess radiological consequences to the public, including brief discussions of potential exposure pathways, routine and accidental releases, and their consequences Responses to the requirements described in the Environmental Regulatory Guide for Radiological Effluent Monitoring and Environmental Surveillance (DOE, 1991). This document references DOE orders and other federal and state regulations affecting environmental monitoring programs at the site. WIPP procedures, which implement

  9. Mutations in β-Lactamase AmpC Increase Resistance of Pseudomonas aeruginosa Isolates to Antipseudomonal Cephalosporins

    PubMed Central

    Berrazeg, M.; Jeannot, K.; Ntsogo Enguéné, Véronique Yvette; Broutin, I.; Loeffert, S.; Fournier, D.

    2015-01-01

    Mutation-dependent overproduction of intrinsic β-lactamase AmpC is considered the main cause of resistance of clinical strains of Pseudomonas aeruginosa to antipseudomonal penicillins and cephalosporins. Analysis of 31 AmpC-overproducing clinical isolates exhibiting a greater resistance to ceftazidime than to piperacillin-tazobactam revealed the presence of 17 mutations in the β-lactamase, combined with various polymorphic amino acid substitutions. When overexpressed in AmpC-deficient P. aeruginosa 4098, the genes coding for 20/23 of these AmpC variants were found to confer a higher (2-fold to >64-fold) resistance to ceftazidime and ceftolozane-tazobactam than did the gene from reference strain PAO1. The mutations had variable effects on the MICs of ticarcillin, piperacillin-tazobactam, aztreonam, and cefepime. Depending on their location in the AmpC structure and their impact on β-lactam MICs, they could be assigned to 4 distinct groups. Most of the mutations affecting the omega loop, the R2 domain, and the C-terminal end of the protein were shared with extended-spectrum AmpCs (ESACs) from other Gram-negative species. Interestingly, two new mutations (F121L and P154L) were predicted to enlarge the substrate binding pocket by disrupting the stacking between residues F121 and P154. We also found that the reported ESACs emerged locally in a variety of clones, some of which are epidemic and did not require hypermutability. Taken together, our results show that P. aeruginosa is able to adapt to efficacious β-lactams, including the newer cephalosporin ceftolozane, through a variety of mutations affecting its intrinsic β-lactamase, AmpC. Data suggest that the rates of ESAC-producing mutants are ≥1.5% in the clinical setting. PMID:26248364

  10. Characterization of stress-responsive behavior in Pseudomonas aeruginosa PAO: isolation of Tn3-lacZYA fusions with novel damage-inducible (din) promoters.

    PubMed Central

    Warner-Bartnicki, A L; Miller, R V

    1992-01-01

    Although the pervasive soil and water microorganism Pseudomonas aeruginosa demonstrates heightened sensitivity to UV radiation, this species possesses a recA gene that, based on structural and functional properties, could mediate a DNA damage-responsive regulon similar to the SOS regulon of Escherichia coli. To determine whether P. aeruginosa encodes such stress-inducible genes, the response of P. aeruginosa to DNA-damaging agents including far-UV radiation (UVC) and the quinolone antimicrobial agent norfloxacin was investigated by monitoring the expression of fusions linking P. aeruginosa promoters to a beta-galactosidase reporter gene. These fusions were obtained by Tn3-HoHoI insertional mutagenesis of a P. aeruginosa genomic library. Eight different damage-inducible (din) gene fusions were isolated which lack homology to the P. aeruginosa recA gene. Expression of the three gene fusions studied, dinA::lacZYA, dinB::lacZYA, and dinC::lacZYA, increased following UVC and quinolone exposure but not following heat shock. Similar to E. coli SOS genes, the din genes were induced to different extents and with dissimilar kinetics following UVC irradiation. PMID:1312530

  11. Characterization of stress-responsive behavior in Pseudomonas aeruginosa PAO: isolation of Tn3-lacZYA fusions with novel damage-inducible (din) promoters.

    PubMed

    Warner-Bartnicki, A L; Miller, R V

    1992-03-01

    Although the pervasive soil and water microorganism Pseudomonas aeruginosa demonstrates heightened sensitivity to UV radiation, this species possesses a recA gene that, based on structural and functional properties, could mediate a DNA damage-responsive regulon similar to the SOS regulon of Escherichia coli. To determine whether P. aeruginosa encodes such stress-inducible genes, the response of P. aeruginosa to DNA-damaging agents including far-UV radiation (UVC) and the quinolone antimicrobial agent norfloxacin was investigated by monitoring the expression of fusions linking P. aeruginosa promoters to a beta-galactosidase reporter gene. These fusions were obtained by Tn3-HoHoI insertional mutagenesis of a P. aeruginosa genomic library. Eight different damage-inducible (din) gene fusions were isolated which lack homology to the P. aeruginosa recA gene. Expression of the three gene fusions studied, dinA::lacZYA, dinB::lacZYA, and dinC::lacZYA, increased following UVC and quinolone exposure but not following heat shock. Similar to E. coli SOS genes, the din genes were induced to different extents and with dissimilar kinetics following UVC irradiation.

  12. Palivizumab prophylaxis in infants with cystic fibrosis does not delay first isolation of Pseudomonas aeruginosa or Staphylococcus aureus.

    PubMed

    Buchs, Clélia; Dalphin, Marie-Laure; Sanchez, Stéphane; Perceval, Marie; Coutier, Laurianne; Mainguy, Catherine; Kassaï-Koupaï, Behrouz; Reix, Philippe

    2017-07-01

    Respiratory syncytial virus (RSV) infections may worsen cystic fibrosis (CF) lung disease and favor Pseudomonas aeruginosa (Pa) or Staphylococcus aureus (Sa) acquisition, which is of particular importance in the youngest patients. We aimed to determine the effectiveness of PVZ on microbiological outcomes in young children with CF. We conducted a retrospective case-control study to compare these outcomes in children who systematically received PVZ (PVZ+; n = 40) or not (PVZ-; n = 140). One case was matched with at least three same-gender controls born the same year and month. Median (range) age at first Pa isolation was not statistically different between PVZ- (12.3 [3.8-32.6] months) and PVZ+ (10.4 [1.2-33.0] months; p = 0.953) patients. A similar trend was found for Sa (PVZ+: 6.4 [2.0-59.0] months; PVZ-: 3.8 [0.1-74.1] months; p = 0.191). The proportion of Pa isolations by 3 years of age did not differ between groups (PVZ+ 40% vs. PVZ- 41.4%), but this proportion was higher for Sa in the PVZ+ group (97%) than in the PVZ- group (85%; p = 0.001). Healthcare consumption and growth outcomes did not significantly differ between groups. Systematic PVZ use did not delay key pathogen acquisition in young children with CF. What is known: • Palivizumab is the only available monoclonal antibody against respiratory syncytial virus infection. • Whether or not it is useful in infants with cystic fibrosis remains controversial. What is new: • Palivizumab does not delay key pathogens (Pseudomonas aeruginosa, Staphylococcus aureus) first isolation in young children with cystic fibrosis. • Palivizumab does not reduce healthcare consumption or improve growth during the first 3 years of life of young children with cystic fibrosis.

  13. Detection of KPC Carbapenemase in Pseudomonas aeruginosa Isolated From Clinical Samples Using Modified Hodge Test and Boronic Acid Phenotypic Methods and Their Comparison With the Polymerase Chain Reaction

    PubMed Central

    Falahat, Saeed; Shojapour, Mana; Sadeghi, Abdorrahim

    2016-01-01

    Background Bacterial resistance to antibiotics has become a major source of concern for public health. Pseudomonas aeruginosa strains are important opportunistic pathogens. These bacteria have a high resistance to a wide range of existing antimicrobials and antibiotics. Objectives The present study was performed to evaluate the frequency of KPC in P. aeruginosa isolated from clinical samples of educational hospitals of Arak University of Medical Sciences, using the mentioned phenotypic and genotypic methods. Materials and Methods One hundred and eight non-duplicate clinical isolates of P. aeruginosa were collected from hospitals of Arak University of Medical Sciences, Arak, Iran. Antibacterial susceptibility was determined by the disk diffusion method. KPC production was confirmed by the Modified Hodge Test (MHT), which is a phenotypic test, and combined-disk test with boronic acid and the Polymerase Chain Reaction (PCR). Results In the present study, 13 isolates (12%) of P. aeruginosa were positive for KPC, using PCR. Comparison of the two phenotypic methods used in this study showed that boronic acid is more sensitive than MHT in identification of KPC-producing strains (84.6% vs. 77%). Conclusions Utilization of reliable methods for identifying carbapenemase-producing strains and determining their antibiotic resistance pattern could have a very important role in treatment of infections caused by these strains. A substantial amount of P. aeruginosa isolated from clinical samples of hospitals in Arak (Iran) produce KPC carbapenemase. Due to their low specificity, MHT and boronic acid phenotypic methods could not completely identify KPC-producing P. aeruginosa. However, the sensitivity of boronic acid phenotypic method in detection of KPC was higher than MHT. PMID:27800140

  14. Similar Frequencies of Pseudomonas aeruginosa Isolates Producing KPC and VIM Carbapenemases in Diverse Genetic Clones at Tertiary-Care Hospitals in Medellín, Colombia

    PubMed Central

    Vanegas, Johanna M.; Cienfuegos, Astrid V.; Ocampo, Ana M.; López, Lucelly; del Corral, Helena; Roncancio, Gustavo; Sierra, Patricia; Echeverri-Toro, Lina; Ospina, Sigifredo; Maldonado, Natalia; Robledo, Carlos; Restrepo, Andrea

    2014-01-01

    Carbapenem-resistant Pseudomonas aeruginosa has become a serious health threat worldwide due to the limited options available for its treatment. Understanding its epidemiology contributes to the control of antibiotic resistance. The aim of this study was to describe the clinical and molecular characteristics of infections caused by carbapenem-resistant P. aeruginosa isolates in five tertiary-care hospitals in Medellín, Colombia. A cross-sectional study was conducted in five tertiary-care hospitals from June 2012 to March 2014. All hospitalized patients infected by carbapenem-resistant P. aeruginosa were included. Clinical information was obtained from medical records. Molecular analyses included PCR for detection of blaVIM, blaIMP, blaNDM, blaOXA-48, and blaKPC genes plus pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) for molecular typing. A total of 235 patients were enrolled: 91.1% of them were adults (n = 214), 88.1% (n = 207) had prior antibiotic use, and 14.9% (n = 35) had urinary tract infections. The blaVIM-2 and blaKPC-2 genes were detected in 13.6% (n = 32) and 11.5% (n = 27), respectively, of all isolates. Two isolates harbored both genes simultaneously. For KPC-producing isolates, PFGE revealed closely related strains within each hospital, and sequence types (STs) ST362 and ST235 and two new STs were found by MLST. With PFGE, VIM-producing isolates appeared highly diverse, and MLST revealed ST111 in four hospitals and five new STs. These results show that KPC-producing P. aeruginosa is currently disseminating rapidly and occurring at a frequency similar to that of VIM-producing P. aeruginosa isolates (approximately 1:1 ratio) in Medellín, Colombia. Diverse genetic backgrounds among resistant strains suggest an excessive antibiotic pressure resulting in the selection of resistant strains. PMID:25210071

  15. Similar frequencies of Pseudomonas aeruginosa isolates producing KPC and VIM carbapenemases in diverse genetic clones at tertiary-care hospitals in Medellín, Colombia.

    PubMed

    Vanegas, Johanna M; Cienfuegos, Astrid V; Ocampo, Ana M; López, Lucelly; del Corral, Helena; Roncancio, Gustavo; Sierra, Patricia; Echeverri-Toro, Lina; Ospina, Sigifredo; Maldonado, Natalia; Robledo, Carlos; Restrepo, Andrea; Jiménez, J Natalia

    2014-11-01

    Carbapenem-resistant Pseudomonas aeruginosa has become a serious health threat worldwide due to the limited options available for its treatment. Understanding its epidemiology contributes to the control of antibiotic resistance. The aim of this study was to describe the clinical and molecular characteristics of infections caused by carbapenem-resistant P. aeruginosa isolates in five tertiary-care hospitals in Medellín, Colombia. A cross-sectional study was conducted in five tertiary-care hospitals from June 2012 to March 2014. All hospitalized patients infected by carbapenem-resistant P. aeruginosa were included. Clinical information was obtained from medical records. Molecular analyses included PCR for detection of bla(VIM), bla(IMP), bla(NDM), bla(OXA-48), and bla(KPC) genes plus pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) for molecular typing. A total of 235 patients were enrolled: 91.1% of them were adults (n = 214), 88.1% (n = 207) had prior antibiotic use, and 14.9% (n = 35) had urinary tract infections. The bla(VIM-2) and bla(KPC-2) genes were detected in 13.6% (n = 32) and 11.5% (n = 27), respectively, of all isolates. Two isolates harbored both genes simultaneously. For KPC-producing isolates, PFGE revealed closely related strains within each hospital, and sequence types (STs) ST362 and ST235 and two new STs were found by MLST. With PFGE, VIM-producing isolates appeared highly diverse, and MLST revealed ST111 in four hospitals and five new STs. These results show that KPC-producing P. aeruginosa is currently disseminating rapidly and occurring at a frequency similar to that of VIM-producing P. aeruginosa isolates (approximately 1:1 ratio) in Medellín, Colombia. Diverse genetic backgrounds among resistant strains suggest an excessive antibiotic pressure resulting in the selection of resistant strains.

  16. [The experience of implementation of REP-u RAPD-polymerase chain reaction in epidemiologic characteristic of nosocomial isolates Pseudomonas aeruginosa].

    PubMed

    Kuznetsova, M V; Maksimova, A V; Karpunina, T I

    2015-03-01

    The article presents comparative evaluation of diagnostic value of technique REP- u RAPD-polymerase chain reaction applied under genetic typing of clinical isolates of Pseudomonas Aeruginosa. The strains are isolated in different hospital departments of medical institutions in adult (8 medical institutions; n = 145) and children (5 medical institutions; n = 151) medical networks. The results of study demonstrated different boundary capacity of three reactions. The Simpson discrimination index made up to 0.993, 0.875 and 0.639 for RAPD-, ERIC- and BOX-polymerase chain reaction correspondingly. The RAPD-polymerase chain reaction makes it possible to detect individual characteristics of strains. Out of two alternatives the REP-polymerase chain reaction demonstrated its advantage, besides only with one primer ERIC2. The BOX-polymerase chain reaction has a least discriminating capacity under typing of isolates P. aeruginosa, detecting only species' characteristics. The clinical strains P. aeruginosa are distributed on 24 genome groups and 52 isolates had individual genotypes. The evaluation of results of genetic typing permitted to point out both similarity of tendencies in propagation of strains of P. aeruginosa among hospitalized adults and adolescents and specificity of detection in neonatal clinics. It is obvious that hospitals of different profiles, including departments of reanimation and intensive therapy represent specific ecological environment significantly different in its level of endogenous and exogenous infection.

  17. Application of Whole-Genome Sequencing Data for O-Specific Antigen Analysis and In Silico Serotyping of Pseudomonas aeruginosa Isolates

    PubMed Central

    Thrane, Sandra Wingaard; Taylor, Véronique L.; Lund, Ole

    2016-01-01

    Accurate typing methods are required for efficient infection control. The emergence of whole-genome sequencing (WGS) technologies has enabled the development of genome-based methods applicable for routine typing and surveillance of bacterial pathogens. In this study, we developed the Pseudomonas aeruginosa serotyper (PAst) program, which enabled in silico serotyping of P. aeruginosa isolates using WGS data. PAst has been made publically available as a web service and aptly facilitates high-throughput serotyping analysis. The program overcomes critical issues such as the loss of in vitro typeability often associated with P. aeruginosa isolates from chronic infections and quickly determines the serogroup of an isolate based on the sequence of the O-specific antigen (OSA) gene cluster. Here, PAst analysis of 1,649 genomes resulted in successful serogroup assignments in 99.27% of the cases. This frequency is rarely achievable by conventional serotyping methods. The limited number of nontypeable isolates found using PAst was the result of either a complete absence of OSA genes in the genomes or the artifact of genomic misassembly. With PAst, P. aeruginosa serotype data can be obtained from WGS information alone. PAst is a highly efficient alternative to conventional serotyping methods in relation to outbreak surveillance of serotype O12 and other high-risk clones, while maintaining backward compatibility to historical serotype data. PMID:27098958

  18. Phenol degrading ability of Rhodococcus pyrinidivorans and Pseudomonas aeruginosa isolated from activated sludge plants in South Africa.

    PubMed

    Kumari, Sheena; Chetty, Dereshen; Ramdhani, Nishani; Bux, Faizal

    2013-01-01

    Phenol, a common constituent in many industrial wastewaters is a major pollutant and has several adverse effects on the environment. The potential of various microorganisms to utilize phenol for their metabolic activity has been observed to be an effective means of remediating this toxic compound from the environment particularly wastewater. Five indigenous bacterial isolates (PD1-PD5) were obtained from phenol bearing industrial wastewater using the mineral salts medium. The isolates were further characterized based on their morphology, biochemical reactions and 16S rRNA phylogeny. The 16S rRNA sequence analysis using universal primers (27f/1492r) revealed that PD1, PD2, PD3 and PD4 were closely related to the actinomycete Rhodococcus pyrinidivorans (99%) and PD5 to Pseudomonas aeruginosa (99%). Growth kinetic patterns and phenol degradation abilities of the two representative isolates (PD1 and PD5) were also evaluated. Both the species were effective in utilizing phenol as the sole carbon source and could tolerate phenol concentrations of up to 500 to 600 mg/L. The ability of these isolates to utilize higher concentrations of phenol as their sole carbon source makes them potential candidates and better competitors in the bioremediation process.

  19. Bdellovibrio bacteriovorus directly attacks Pseudomonas aeruginosa and Staphylococcus aureus Cystic fibrosis isolates.

    PubMed

    Iebba, Valerio; Totino, Valentina; Santangelo, Floriana; Gagliardi, Antonella; Ciotoli, Luana; Virga, Alessandra; Ambrosi, Cecilia; Pompili, Monica; De Biase, Riccardo V; Selan, Laura; Artini, Marco; Pantanella, Fabrizio; Mura, Francesco; Passariello, Claudio; Nicoletti, Mauro; Nencioni, Lucia; Trancassini, Maria; Quattrucci, Serena; Schippa, Serena

    2014-01-01

    Bdellovibrio bacteriovorus is a predator bacterial species found in the environment and within the human gut, able to attack Gram-negative prey. Cystic fibrosis (CF) is a genetic disease which usually presents lung colonization by Pseudomonas aeruginosa or Staphylococcus aureus biofilms. Here, we investigated the predatory behavior of B. bacteriovorus against these two pathogenic species with: (1) broth culture; (2) "static" biofilms; (3) field emission scanning electron microscope (FESEM); (4) "flow" biofilms; (5) zymographic technique. We had the first evidence of B. bacteriovorus survival with a Gram-positive prey, revealing a direct cell-to-cell contact with S. aureus and a new "epibiotic" foraging strategy imaged with FESEM. Mean attaching time of HD100 to S. aureus cells was 185 s, while "static" and "flow" S. aureus biofilms were reduced by 74 (at 24 h) and 46% (at 20 h), respectively. Furthermore, zymograms showed a differential bacteriolytic activity exerted by the B. bacteriovorus lysates on P. aeruginosa and S. aureus. The dual foraging system against Gram-negative (periplasmic) and Gram-positive (epibiotic) prey could suggest the use of B. bacteriovorus as a "living antibiotic" in CF, even if further studies are required to simulate its in vivo predatory behavior.

  20. Bdellovibrio bacteriovorus directly attacks Pseudomonas aeruginosa and Staphylococcus aureus Cystic fibrosis isolates

    PubMed Central

    Iebba, Valerio; Totino, Valentina; Santangelo, Floriana; Gagliardi, Antonella; Ciotoli, Luana; Virga, Alessandra; Ambrosi, Cecilia; Pompili, Monica; De Biase, Riccardo V.; Selan, Laura; Artini, Marco; Pantanella, Fabrizio; Mura, Francesco; Passariello, Claudio; Nicoletti, Mauro; Nencioni, Lucia; Trancassini, Maria; Quattrucci, Serena; Schippa, Serena

    2014-01-01

    Bdellovibrio bacteriovorus is a predator bacterial species found in the environment and within the human gut, able to attack Gram-negative prey. Cystic fibrosis (CF) is a genetic disease which usually presents lung colonization by Pseudomonas aeruginosa or Staphylococcus aureus biofilms. Here, we investigated the predatory behavior of B. bacteriovorus against these two pathogenic species with: (1) broth culture; (2) “static” biofilms; (3) field emission scanning electron microscope (FESEM); (4) “flow” biofilms; (5) zymographic technique. We had the first evidence of B. bacteriovorus survival with a Gram-positive prey, revealing a direct cell-to-cell contact with S. aureus and a new “epibiotic” foraging strategy imaged with FESEM. Mean attaching time of HD100 to S. aureus cells was 185 s, while “static” and “flow” S. aureus biofilms were reduced by 74 (at 24 h) and 46% (at 20 h), respectively. Furthermore, zymograms showed a differential bacteriolytic activity exerted by the B. bacteriovorus lysates on P. aeruginosa and S. aureus. The dual foraging system against Gram-negative (periplasmic) and Gram-positive (epibiotic) prey could suggest the use of B. bacteriovorus as a “living antibiotic” in CF, even if further studies are required to simulate its in vivo predatory behavior. PMID:24926292

  1. Molecular typing and resistance mechanisms of carbapenem resistant Pseudomonas aeruginosa isolated from a Chinese surgical intensive care unit.

    PubMed

    Yi, Meiying; Wang, Pengyuan; Liu, Yucun

    2014-01-01

    Carbapenems are an important class of drugs for the treatment of Pseudomonas aeruginosa (P. aeruginosa) infections. However, carbapenem resistance has been commonly observed in nonfermenter species of bacteria. The purpose of this study was to investigate the molecular epidemiology and carbapenem resistant mechanisms of P. aeruginosa isolated from a surgical intensive care unit (SICU) in China. The molecular typing was analyzed by REP-PCR. Enzyme activity was measured with a 260 nm wavelength spectrophotometer. The levels of outer membrane proteins OprD and OprN were measured by Western blotting. The levels of mexA gene transcriptional expression were measured by quantitative real-time PCR. The metallo-beta-lactamase genes IMP, VIM, SPM, GES, and GIM were amplified by PCR. DNA fragments were sequenced by an automated ABI PRISM 3700. Forty-two strains resistant to carbapenems isolated from a SICU were analyzed. REP-PCR revealed 34 belonging to type A, a predominant strain in this SICU. But we did not find metallo-beta-lactamases IMP, VIM, SPM, GES, or GIM genes by PCR. With a three-dimensional extract test, we found 34 strains producing high levels of AmpC enzymes. We also observed the activity of beta-lactamases enzymes in the imipenem resistant group, which was statistically different from the sensitive group. Western blotting revealed that 23 strains showed loss of OprD, 18 strains had decreased OprD expression, and 14 strains expressed OprN. We discovered 27 strains that overexpressed mexA by quantitative real-time PCR, and the resistance rate to meropenem was statistically different between the overexpressing group and the low-expressing group. Nucleotide sequences and deduced amino acid sequence analysis revealed that eight strains carried mutations in the mexR gene operon down regulating MexAB-OprM. The nucleotide sequences of mexR genes from PA36, PA41 and PA48 were submitted to the Genebank with accession numbers of AY899299, AY899300, and AY899301. There

  2. Antimicrobial Activity of Ceftolozane-Tazobactam Tested against Enterobacteriaceae and Pseudomonas aeruginosa with Various Resistance Patterns Isolated in U.S. Hospitals (2011-2012)

    PubMed Central

    Flamm, Robert K.; Sader, Helio S.; Jones, Ronald N.

    2013-01-01

    Ceftolozane/tazobactam, a novel antimicrobial agent with activity against Pseudomonas aeruginosa (including drug-resistant strains) and other common Gram-negative pathogens (including most extended-spectrum-β-lactamase [ESBL]-producing Enterobacteriaceae strains), and comparator agents were susceptibility tested by a reference broth microdilution method against 7,071 Enterobacteriaceae and 1,971 P. aeruginosa isolates. Isolates were collected consecutively from patients in 32 medical centers across the United States during 2011 to 2012. Overall, 15.7% and 8.9% of P. aeruginosa isolates were classified as multidrug resistant (MDR) and extensively drug resistant (XDR), and 8.4% and 1.2% of Enterobacteriaceae were classified as MDR and XDR. No pandrug-resistant (PDR) Enterobacteriaceae isolates and only one PDR P. aeruginosa isolate were detected. Ceftolozane/tazobactam was the most potent (MIC50/90, 0.5/2 μg/ml) agent tested against P. aeruginosa and demonstrated good activity against 310 MDR strains (MIC50/90, 2/8 μg/ml) and 175 XDR strains (MIC50/90, 4/16 μg/ml). Ceftolozane/tazobactam exhibited high overall activity (MIC50/90, 0.25/1 μg/ml) against Enterobacteriaceae and retained activity (MIC50/90, 4/>32 μg/ml) against many 601 MDR strains but not against the 86 XDR strains (MIC50, >32 μg/ml). Ceftolozane/tazobactam was highly potent (MIC50/90, 0.25/0.5 μg/ml) against 2,691 Escherichia coli isolates and retained good activity against most ESBL-phenotype E. coli isolates (MIC50/90, 0.5/4 μg/ml), but activity was low against ESBL-phenotype Klebsiella pneumoniae isolates (MIC50/90, 32/>32 μg/ml), explained by the high rate (39.8%) of meropenem coresistance observed in this species phenotype. In summary, ceftolozane/tazobactam demonstrated high potency and broad-spectrum activity against many contemporary Enterobacteriaceae and P. aeruginosa isolates collected in U.S. medical centers. Importantly, ceftolozane/tazobactam retained potency against many MDR and

  3. Metallo-β-Lactamase Gene blaIMP-15 in a Class 1 Integron, In95, from Pseudomonas aeruginosa Clinical Isolates from a Hospital in Mexico▿

    PubMed Central

    Garza-Ramos, U.; Morfin-Otero, R.; Sader, H. S.; Jones, R. N.; Hernández, E.; Rodriguez-Noriega, E.; Sanchez, A.; Carrillo, B.; Esparza-Ahumada, S.; Silva-Sanchez, J.

    2008-01-01

    During 2003, 40 carbapenem-resistant Pseudomonas aeruginosa clinical isolates collected in a Mexican tertiary-care hospital were screened for metallo-β-lactamase production. Thirteen isolates produced IMP-15, and 12 had a single pulsed-field gel electrophoresis pattern. The blaIMP-15 gene cassette was inserted in a plasmid-borne integron with a unique array of gene cassettes and was named In95. PMID:18490501

  4. In Vitro Activity of Ceftazidime-Avibactam against Contemporary Pseudomonas aeruginosa Isolates from U.S. Medical Centers by Census Region, 2014.

    PubMed

    Huband, Michael D; Castanheira, Mariana; Flamm, Robert K; Farrell, David J; Jones, Ronald N; Sader, Helio S

    2016-04-01

    Thein vitroantibacterial activities of ceftazidime-avibactam and comparator agents were evaluated using reference broth microdilution methods against 1,743Pseudomonas aeruginosaisolates collected in 2014 from 69 U.S. medical centers, representing each of the nine census regions. Ceftazidime-avibactam demonstrated potent activity againstP. aeruginosa, including many isolates not susceptible to ceftazidime, meropenem, and piperacillin-tazobactam. In each of the nine census regions, ceftazidime-avibactam demonstrated the highest percentage of susceptible isolates.

  5. Optimization of environmental parameters for biodegradation of alpha and beta endosulfan in soil slurry by Pseudomonas aeruginosa.

    PubMed

    Arshad, M; Hussain, S; Saleem, M

    2008-02-01

    To determine optimal environmental conditions for achieving biodegradation of alpha- and beta-endosulfan in soil slurries following inoculation with an endosulfan degrading strain of Pseudomonas aeruginosa. Parameters that were investigated included soil texture, soil slurry: water ratios, initial inoculum size, pH, incubation temperature, aeration, and the use of exogenous sources of organic and amino acids. The results showed that endosulfan degradation was most effectively achieved at an initial inoculum size of 600 microl (OD = 0 x 86), incubation temperature of 30 degrees C, in aerated slurries at pH 8, in loam soil. Under these conditions, the bacterium removed more than 85% of spiked alpha- and beta-endosulfan (100 mg l(-1)) after 16 days. Abiotic degradation in noninoculated control medium within same incubation period was about 16%. Biodegradation of endosulfan varied in different textured soils, being more rapid in course textured soil than in fine textured soil. Increasing the soil contents in the slurry above 15% resulted in less biodegradation of endosulfan. Exogenous application of organic acids (citric acid and acetic acid) and amino acids (L-methionine and L-cystein) had stimulatory and inhibitory effects, respectively, on biodegradation of endosulfan. The results of this study demonstrated that biodegradation of endosulfan by Ps. aeruginosa in soil sediments enhanced significantly under optimized environmental conditions. Endosulfan is a commonly used pesticide that can contaminate soil, wetlands and groundwater. Our study demonstrates that bioaugmentation of contaminated soils with an endosulfan degrading bacterium under optimized conditions provides an effective bioremediation strategy.

  6. Genes Required for and Effects of Alginate Overproduction Induced by Growth of Pseudomonas aeruginosa on Pseudomonas Isolation Agar Supplemented with Ammonium Metavanadate

    PubMed Central

    Damron, F. Heath; Barbier, Mariette; McKenney, Elizabeth S.; Schurr, Michael J.

    2013-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen that can adapt to changing environments and can secrete an exopolysaccharide known as alginate as a protection response, resulting in a colony morphology and phenotype referred to as mucoid. However, how P. aeruginosa senses its environment and activates alginate overproduction is not fully understood. Previously, we showed that Pseudomonas isolation agar supplemented with ammonium metavanadate (PIAAMV) induces P. aeruginosa to overproduce alginate. Vanadate is a phosphate mimic and causes protein misfolding by disruption of disulfide bonds. Here we used PIAAMV to characterize the pathways involved in inducible alginate production and tested the global effects of P. aeruginosa growth on PIAAMV by a mutant library screen, by transcriptomics, and in a murine acute virulence model. The PA14 nonredundant mutant library was screened on PIAAMV to identify new genes that are required for the inducible alginate stress response. A functionally diverse set of genes encoding products involved in cell envelope biogenesis, peptidoglycan remodeling, uptake of phosphate and iron, phenazine biosynthesis, and other processes were identified as positive regulators of the mucoid phenotype on PIAAMV. Transcriptome analysis of P. aeruginosa cultures growing in the presence of vanadate showed differential expression of genes involved in virulence, envelope biogenesis, and cell stress pathways. In this study, it was observed that growth on PIAAMV attenuates P. aeruginosa in a mouse pneumonia model. Induction of alginate overproduction occurs as a stress response to protect P. aeruginosa, but it may be possible to modulate and inhibit these pathways based on the new genes identified in this study. PMID:23794622

  7. [Molecular characterization of carbapenem-resistant and metallo-beta-lactamase-producing Pseudomonas aeruginosa isolated from blood cultures from children and teenagers with cancer].

    PubMed

    Fernandes, Thais Avila; Pereira, Carlos Alberto Pires; Petrili, Antônio Sergio; Pignatari, Antônio Carlos Campos

    2010-01-01

    The objective of this study was to evaluate the prevalence and dissemination of carbapenem-resistant and metallo-beta-lactamase-producing Pseudomonas aeruginosa isolated from blood-stream samples (2000-2005) that were collected from patients admitted to the Institute of Pediatric Oncology, UNIFESP (IOP-GRAACC). Fifty-six P. aeruginosa samples were isolated from 49 patients. Thirty-two of these samples were classified as carbapenem-resistant using the disc diffusion method and were subjected to the PCR reaction in order to detect MBL genes. Eighteen of these 32 isolates showed the blaSPM-1 gene. Eight samples selected in different years over the study period presented the same genetic profile according to pulsed-field gel electrophoresis. The antimicrobial therapy was considered adequate for only 23.5% of the patients with bacteremia due to P. aeruginosa carrying the blaSPM-1 gene, and a high lethality rate of 70.6% was observed during the 30-day period after bacteremia and an inadequate initial antibiotic regimen. We detected the presence of a clone of carbapenem-resistant P. aeruginosa carrying blaSPM-1 that persisted in blood culture samples over a six-year period at the institution, with high lethality, thus justifying rigorous epidemiological surveillance and a rearrangement of the antimicrobial therapy regimens at the institution.

  8. Genetic analyses of Pseudomonas aeruginosa isolated from healthy captive snakes: evidence of high inter- and intrasite dissemination and occurrence of antibiotic resistance genes.

    PubMed

    Colinon, Céline; Jocktane, Dominique; Brothier, Elisabeth; Rossolini, Gian Maria; Cournoyer, Benoit; Nazaret, Sylvie

    2010-03-01

    Faecal carriage of Pseudomonas aeruginosa was investigated by selective plating and PCR identification test, among healthy captive snakes from zoological and private collections from France as well as from wild snakes from Guinea. P. aeruginosa faecal carriage among captive snakes was high (72 out of 83 individuals), but low among wild specimen (3 out of 23 individuals). Genetic diversity analyses of the isolates, based on SpeI-PFGE profiles, evidenced five dominant clones or clonal complexes spreading among snakes within a site and between sites and persisting over time. Similar clones or clonal complexes were detected from mouth swabs of the owners and from water and preys used to feed the snakes, evidencing various sources of snake colonization and the first cases of P. aeruginosa cross-contamination between snakes and owners. These observations led to the conclusion that P. aeruginosa behaves as an opportunistic species within snakes in captivity and that colonization and dissemination occurs consecutively to processes similar to those identified within the hospital. Antibiotic susceptibility testing showed that most isolates had a wild-type resistance profile except for one persistent clone isolated from both snakes and preys that harboured multiple antimicrobial resistance genes mediated by an integron carrying the qacH, aadB, aadA2 and cmlA10 cassettes, and a tetA(C)-carrying transposon. Biocides or antibiotics used in the zoological garden could have led to the acquisition of this integron.

  9. Biofilm Filtrates of Pseudomonas aeruginosa Strains Isolated from Cystic Fibrosis Patients Inhibit Preformed Aspergillus fumigatus Biofilms via Apoptosis

    PubMed Central

    Shirazi, Fazal; Ferreira, Jose A. G.; Stevens, David A.; Clemons, Karl V.; Kontoyiannis, Dimitrios P.

    2016-01-01

    Pseudomonas aeruginosa (Pa) and Aspergillus fumigatus (Af) colonize cystic fibrosis (CF) patient airways. Pa culture filtrates inhibit Af biofilms, and Pa non-CF, mucoid (Muc-CF) and nonmucoid CF (NMuc-CF) isolates form an ascending inhibitory hierarchy. We hypothesized this activity is mediated through apoptosis induction. One Af and three Pa (non-CF, Muc-CF, NMuc-CF) reference isolates were studied. Af biofilm was formed in 96 well plates for 16 h ± Pa biofilm filtrates. After 24 h, apoptosis was characterized by viability dye DiBAc, reactive oxygen species (ROS) generation, mitochondrial membrane depolarization, DNA fragmentation and metacaspase activity. Muc-CF and NMuc-CF filtrates inhibited and damaged Af biofilm (p<0.0001). Intracellular ROS levels were elevated (p<0.001) in NMuc-CF-treated Af biofilms (3.7- fold) compared to treatment with filtrates from Muc-CF- (2.5- fold) or non-CF Pa (1.7- fold). Depolarization of mitochondrial potential was greater upon exposure to NMuc-CF (2.4-fold) compared to Muc-CF (1.8-fold) or non-CF (1.25-fold) (p<0.0001) filtrates. Exposure to filtrates resulted in more DNA fragmentation in Af biofilm, compared to control, mediated by metacaspase activation. In conclusion, filtrates from CF-Pa isolates were more inhibitory against Af biofilms than from non-CF. The apoptotic effect involves mitochondrial membrane damage associated with metacaspase activation. PMID:26930399

  10. Biofilm Filtrates of Pseudomonas aeruginosa Strains Isolated from Cystic Fibrosis Patients Inhibit Preformed Aspergillus fumigatus Biofilms via Apoptosis.

    PubMed

    Shirazi, Fazal; Ferreira, Jose A G; Stevens, David A; Clemons, Karl V; Kontoyiannis, Dimitrios P

    2016-01-01

    Pseudomonas aeruginosa (Pa) and Aspergillus fumigatus (Af) colonize cystic fibrosis (CF) patient airways. Pa culture filtrates inhibit Af biofilms, and Pa non-CF, mucoid (Muc-CF) and nonmucoid CF (NMuc-CF) isolates form an ascending inhibitory hierarchy. We hypothesized this activity is mediated through apoptosis induction. One Af and three Pa (non-CF, Muc-CF, NMuc-CF) reference isolates were studied. Af biofilm was formed in 96 well plates for 16 h ± Pa biofilm filtrates. After 24 h, apoptosis was characterized by viability dye DiBAc, reactive oxygen species (ROS) generation, mitochondrial membrane depolarization, DNA fragmentation and metacaspase activity. Muc-CF and NMuc-CF filtrates inhibited and damaged Af biofilm (p<0.0001). Intracellular ROS levels were elevated (p<0.001) in NMuc-CF-treated Af biofilms (3.7- fold) compared to treatment with filtrates from Muc-CF- (2.5- fold) or non-CF Pa (1.7- fold). Depolarization of mitochondrial potential was greater upon exposure to NMuc-CF (2.4-fold) compared to Muc-CF (1.8-fold) or non-CF (1.25-fold) (p<0.0001) filtrates. Exposure to filtrates resulted in more DNA fragmentation in Af biofilm, compared to control, mediated by metacaspase activation. In conclusion, filtrates from CF-Pa isolates were more inhibitory against Af biofilms than from non-CF. The apoptotic effect involves mitochondrial membrane damage associated with metacaspase activation.

  11. [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.

  12. Isolation and characterization of an alginase from mucoid strains of Pseudomonas aeruginosa.

    PubMed

    Linker, A; Evans, L R

    1984-09-01

    Strains of Pseudomonas aeruginosa which produce an alginate-like slime polysaccharide were shown to also synthesize an intracellular enzyme which can degrade these polysaccharides and the seaweed alginic acids. The enzyme acts as an eliminase introducing delta 4,5 unsaturation into the uronic acid moiety. It appears to be a polymannuronide lyase which degrades the polysaccharides, depending on their uronic acid composition, to a series of oligosaccharides, the smallest of which is a disaccharide. L-Guluronic acid linkages are not split. The Pseudomonas alginase resembles other bacterial alginases and enzymes from molluscs but differs in some important properties, such as extent of degradation and linkage preference. Nonmucoid forms of the organism produce detectable but much lower amounts of enzyme.

  13. Chemical alterations in cell envelopes of polymyxin-resistant Pseudomonas aeruginosa isolates.

    PubMed Central

    Gilleland, H E; Lyle, R D

    1979-01-01

    Cell envelopes from Pseudomonas aeruginosa strains resistant to polymyxin were compared with cell envelopes from polymyxin-sensitive strains as to their content of total protein, carbohydrate, and 2-keto-3-deoxyoctonate and as to their protein composition as determined by slab polyacrylamide gel electrophoresis. The cell envelopes of the polymyxin-resistant strains had reduced amounts of lipopolysaccharide, as indicated a reduction in both carbohydrate and 2-keto-3-deoxyoctonate concentrations, and a greatly altered protein composition as shown by polyacrylamide gel electrophoresis. There was a quantitative increase in total cell envelop protein in these strains. However, those protein bands identified as being major outer membrane proteins upon polyacrylamide gel electrophoresis of separated outer and cytoplasmic membranes were reduced greatly in concentration in the polymyxin-resistant cell envelopes. Thus, it appears that polymyxin resistance in these strains is associated with the alteration of the outer membrane through a loss of lipopolysaccharide and outer membrane proteins. Images PMID:222726

  14. Adhesive Capabilities of Staphylococcus Aureus and Pseudomonas Aeruginosa Isolated from Tears of HIV/AIDS Patients to Soft Contact Lenses

    PubMed Central

    B. O., Ajayi; F.E., Kio; F.D., Otajevwo

    2012-01-01

    Fifty conjunctival swab samples collected from ELISA confirmed HIV/AIDS seropositive patients who were referred to the HIV/AIDS laboratories of the University of Benin Teaching Hospital and Central Hospital both based in Benin City, Nigeria were aseptically cultured on appropriate media by standard methods. The resulting isolates/strains, after identification by standard methods, were tested for their ability to adhere to two hydrophobic non-ionic daily wear silicone hydrogel soft contact lenses (i.e. lotrafilcon B, WC 33% and polymacon, WC 38%) as well as to two hydrophilic ionic conventional extended wear silicone hydrogel soft contact lenses (i.e. methafilcon A, WC 55% and omafilcon A, WC 60%) by the adhesiveness/slime production modified vortex/Robin device method. Evidence of adhesiveness/slime production was indicated by presence of a visible stained film lining the surface of the contact lens which was measured and recorded as strong or weak according to the density of the adhered bacterial film. Fourteen (28.0%) Staphylococcus aureus strains and 10 (20.0%) Pseudomonas aeruginosa strains were obtained among other organisms. Staphylococcus aureus strains adhered in decreasing order to lotrafilcon B (55.4 ± 4.7), polymacon (46.4 ± 8.4), methfilcon A (46.4 ± 8.4) and omafilcon A (25.0 ± 6.4) with no significant difference in adhesive strengths of individual strains (P > 0.05). Pseudomonas aeruginosa strains also recorded decreasing adhesive strengths to lotrafilcon B (37.5 ± 8.2), polymacon (28.6 ± 6.3), methafilcon A (26.8 ± 5.5) and omafilcon A (23.2 ± 5.5) also with no significant difference in adhesive strengths of individual strains (P > 0.05). Attachment strengths of Staph. aureus strains to all four contact lenses were higher than those of Pseudomonas aeruginosa strains. Both organisms adhered most to hydrophobic lotrafilcon B and least to hydrophilic omafilcon A. This invitro adhesion studies revealed that daily wear silicone hydrogel low water

  15. Fitness Cost of Fluoroquinolone Resistance in Clinical Isolates of Pseudomonas aeruginosa Differs by Type III Secretion Genotype.

    PubMed

    Agnello, Melissa; Finkel, Steven E; Wong-Beringer, Annie

    2016-01-01

    Fluoroquinolone (FQ) resistance is highly prevalent among clinical strains of Pseudomonas aeruginosa, limiting treatment options. We have reported previously that highly virulent strains containing the exoU gene of the type III secretion system are more likely to be FQ-resistant than strains containing the exoS gene, as well as more likely to acquire resistance-conferring mutations in gyrA/B and parC/E. We hypothesize that FQ-resistance imposes a lower fitness cost on exoU compared to exoS strains, thus allowing for better adaptation to the FQ-rich clinical environment. We created isogenic mutants containing a common FQ-resistance conferring point mutation in parC from three exoU to three exoS clinical isolates and tested fitness in vitro using head-to-head competition assays. The mutation differentially affected fitness in the exoU and exoS strains tested. While the addition of the parC mutation dramatically increased fitness in one of the exoU strains leaving the other two unaffected, all three exoS strains displayed a general decrease in fitness. In addition, we found that exoU strains may be able to compensate for the fitness costs associated with the mutation through better regulation of supercoiling compared to the exoS strains. These results may provide a biological explanation for the observed predominance of the virulent exoU genotype in FQ-resistant clinical subpopulations and represent the first investigation into potential differences in fitness costs of FQ-resistance that are linked to the virulence genotype of P. aeruginosa. Understanding the fitness costs of antibiotic resistance and possibilities of compensation for these costs is essential for the rational development of strategies to combat the problem of antibiotic resistance.

  16. Antimicrobial potentials of Helicteres isora silver nanoparticles against extensively drug-resistant (XDR) clinical isolates of Pseudomonas aeruginosa.

    PubMed

    Mapara, Nikunj; Sharma, Mansi; Shriram, Varsha; Bharadwaj, Renu; Mohite, K C; Kumar, Vinay

    2015-12-01

    Pseudomonas aeruginosa is a leading opportunistic pathogen and its expanding drug resistance is a growing menace to public health. Its ubiquitous nature and multiple resistance mechanisms make it a difficult target for antimicrobial chemotherapy and require a fresh approach for developing new antimicrobial agents against it. The broad-spectrum antibacterial effects of silver nanoparticles (SNPs) make them an excellent candidate for use in the medical field. However, attempts made to check their potency against extensively drug-resistant (XDR) microbes are meager. This study describes the biosynthesis and biostabilization of SNPs by Helicteres isora aqueous fruit extract and their characterization by ultraviolet-visible spectroscopy, transmission electron microscopy, dynamic light scattering, X-ray diffraction, and Fourier transform infrared spectroscopy. Majority of SNPs synthesized were of 8--20-nm size. SNPs exhibited dose-dependent antibacterial activities against four XDR P. aeruginosa (XDR-PA) clinical isolates as revealed by growth curves, with a minimum inhibitory concentration of 300 μg/ml. The SNPs exhibited antimicrobial activity against all strains, with maximum zone of inhibition (16.4 mm) in XRD-PA-2 at 1000 μg/ml. Amongst four strains, their susceptibilities to SNPs were in the following order: XDR-PA-2 > XDR-PA-4 > XDR-PA-3 > XDR-PA-1. The exposure of bacterial cells to 300 μg/ml SNPs resulted into a substantial leakage of reducing sugars and proteins, inactivation of respiratory chain dehydrogenases, and eventual cell death. SNPs also induced lipid peroxidation, a possible underlying factor to membrane porosity. The effects were more pronounced in XDR-PA-2 which may be correlated with its higher susceptibility to SNPs. These results are indicative of SNP-induced turbulence of membranous permeability as an important causal factor in XDR-PA growth inhibition and death.

  17. Fitness Cost of Fluoroquinolone Resistance in Clinical Isolates of Pseudomonas aeruginosa Differs by Type III Secretion Genotype

    PubMed Central

    Agnello, Melissa; Finkel, Steven E.; Wong-Beringer, Annie

    2016-01-01

    Fluoroquinolone (FQ) resistance is highly prevalent among clinical strains of Pseudomonas aeruginosa, limiting treatment options. We have reported previously that highly virulent strains containing the exoU gene of the type III secretion system are more likely to be FQ-resistant than strains containing the exoS gene, as well as more likely to acquire resistance-conferring mutations in gyrA/B and parC/E. We hypothesize that FQ-resistance imposes a lower fitness cost on exoU compared to exoS strains, thus allowing for better adaptation to the FQ-rich clinical environment. We created isogenic mutants containing a common FQ-resistance conferring point mutation in parC from three exoU to three exoS clinical isolates and tested fitness in vitro using head-to-head competition assays. The mutation differentially affected fitness in the exoU and exoS strains tested. While the addition of the parC mutation dramatically increased fitness in one of the exoU strains leaving the other two unaffected, all three exoS strains displayed a general decrease in fitness. In addition, we found that exoU strains may be able to compensate for the fitness costs associated with the mutation through better regulation of supercoiling compared to the exoS strains. These results may provide a biological explanation for the observed predominance of the virulent exoU genotype in FQ-resistant clinical subpopulations and represent the first investigation into potential differences in fitness costs of FQ-resistance that are linked to the virulence genotype of P. aeruginosa. Understanding the fitness costs of antibiotic resistance and possibilities of compensation for these costs is essential for the rational development of strategies to combat the problem of antibiotic resistance. PMID:27757111

  18. Characterisation and antimicrobial activity of biosurfactant extracts produced by Bacillus amyloliquefaciens and Pseudomonas aeruginosa isolated from a wastewater treatment plant.

    PubMed

    Ndlovu, Thando; Rautenbach, Marina; Vosloo, Johann Arnold; Khan, Sehaam; Khan, Wesaal

    2017-12-01

    Biosurfactants are unique secondary metabolites, synthesised non-ribosomally by certain bacteria, fungi and yeast, with their most promising applications as antimicrobial agents and surfactants in the medical and food industries. Naturally produced glycolipids and lipopeptides are found as a mixture of congeners, which increases their antimicrobial potency. Sensitive analysis techniques, such as liquid chromatography coupled to mass spectrometry, enable the fingerprinting of different biosurfactant congeners within a naturally produced crude extract. Bacillus amyloliquefaciens ST34 and Pseudomonas aeruginosa ST5, isolated from wastewater, were screened for biosurfactant production. Biosurfactant compounds were solvent extracted and characterised using ultra-performance liquid chromatography (UPLC) coupled to electrospray ionisation mass spectrometry (ESI-MS). Results indicated that B. amyloliquefaciens ST34 produced C13-16 surfactin analogues and their identity were confirmed by high resolution ESI-MS and UPLC-MS. In the crude extract obtained from P. aeruginosa ST5, high resolution ESI-MS linked to UPLC-MS confirmed the presence of di- and monorhamnolipid congeners, specifically Rha-Rha-C10-C10 and Rha-C10-C10, Rha-Rha-C8-C10/Rha-Rha-C10-C8 and Rha-C8-C10/Rha-C10-C8, as well as Rha-Rha-C12-C10/Rha-Rha-C10-C12 and Rha-C12-C10/Rha-C10-C12. The crude surfactin and rhamnolipid extracts also retained pronounced antimicrobial activity against a broad spectrum of opportunistic and pathogenic microorganisms, including antibiotic resistant Staphylococcus aureus and Escherichia coli strains and the pathogenic yeast Candida albicans. In addition, the rapid solvent extraction combined with UPLC-MS of the crude samples is a simple and powerful technique to provide fast, sensitive and highly specific data on the characterisation of biosurfactant compounds.

  19. Co-Carriage of blaKPC-2 and blaNDM-1 in Clinical Isolates of Pseudomonas aeruginosa Associated with Hospital Infections from India.

    PubMed

    Paul, Deepjyoti; Dhar Chanda, Debadatta; Maurya, Anand Prakash; Mishra, Shweta; Chakravarty, Atanu; Sharma, Gauri Dutt; Bhattacharjee, Amitabha

    2015-01-01

    Global spread of KPC poses to be a serious threat complicating treatment options in hospital settings. The present study investigates the genetic environment of blaKPC-2 among clinical isolates of Pseudomonas aeruginosa from a tertiary referral hospital of India. The study isolates were collected from different wards and clinics of Silchar Medical College and Hospital, India, from 2012-2013. The presence of blaKPC was confirmed by genotypic characterization followed by sequencing. Cloning of the blaKPC-2 gene was performed and the genetic environment of this gene was characterized as well. Transferability of the resistance gene was determined by transformation assay and Southern hybridization. Additionally, restriction mapping was also carried out. Two isolates of P. aeruginosa were found to harbor blaKPC-2, were resistant towards aminoglycosides, quinolone and β-lactam-β-lactamase inhibitor combination. In both the isolates, the resistance determinant was associated with class 1 integron and horizontally transferable. Both the isolates were co-harboring blaNDM-1. The first detection of this integron mediated blaKPC-2 coexisting with blaNDM-1 in P. aeruginosa from India is worrisome, and further investigation is required to track the gene cassette mediated blaKPC-2 in terms of infection control and to prevent the spread of this gene in hospitals as well as in the community.

  20. Biodegradation of isoproturon using a novel Pseudomonas aeruginosa strain JS-11 as a multi-functional bioinoculant of environmental significance.

    PubMed

    Dwivedi, Sourabh; Singh, Braj Raj; Al-Khedhairy, Abdulaziz A; Musarrat, Javed

    2011-01-30

    Biodegradation of phenylurea herbicide isoproturon was studied in soil microcosm bioaugmented with a novel bacterial strain JS-11 isolated from wheat rhizosphere. The molecular characterization based on 16SrDNA sequence homology confirmed its identity as Pseudomonas aeruginosa strain JS-11. The herbicide was completely degraded within 20 days at ambient temperature with the rate constant of 0.08 day(-1), following the first-order rate kinetics. In stationary phase, at a cell density of 6.5 × 10(9) CFU mL(-1), the bacteria produced substantially increased amounts of indole acetic acid (IAA) in the presence of tryptophan as compared with the control. Also, the bacteria exhibited a time-dependent increase in the amount of tri-calcium phosphate solubilization in Pikovskaya's medium. Further screening of the strain JS-11 for auxiliary activities revealed its remarkable capability of producing the siderophores and hydrogen cyanide (HCN), besides antifungal activity against a common phytopathogen Fusarium oxysporum. Thus, the versatile P. aeruginosa strain JS-11 with innate potential for multifarious biological activities is envisaged as a super-bioinoculant for exploitation in the integrated bioremediation, plant growth and disease management (IBPDM) in contaminated agricultural soils.

  1. 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.

  2. Detection of extended spectrum beta lactamases, ampc beta lactamases and metallobetalactamases in clinical isolates of ceftazidime resistant Pseudomonas Aeruginosa.

    PubMed

    Umadevi, Sivaraman; Joseph, Noyal M; Kumari, Kandha; Easow, Joshy M; Kumar, Shailesh; Stephen, Selvaraj; Srirangaraj, Sreenivasan; Raj, Sruthi

    2011-10-01

    We studied the prevalence of ceftazidime resistance in Pseudomonas aeruginosa and the rates of extended-spectrum β-lactamase (ESBL), AmpC β-lactamase (AmpC) and metallo-β-lactamase (MBL) production among the ceftazidime resistant Pseudomonas aeruginosa. A very high rate of MBL production was observed, which suggested it to be an important contributing factor for ceftazidime resistance among Pseudomonas aeruginosa.

  3. Hospital Isolates of Serratia marcescens Transferring Ampicillin, Carbenicillin, and Gentamicin Resistance to Other Gram-Negative Bacteria Including Pseudomonas aeruginosa

    PubMed Central

    Olexy, Vera M.; Bird, Thomas J.; Grieble, Hans G.; Farrand, Stephen K.

    1979-01-01

    Thirteen independent isolates of Serratia marcescens associated with nosocomial urinary tract infections were obtained from the clinical microbiology laboratory at Hines Veterans Administration Hospital. The isolates were resistant to at least ampicillin, carbenicillin, gentamicin, and tobramycin. They could be divided into two groups on the basis of their antibiotypes. Group I (9 strains) showed resistance to 13 antibiotics, including 3 beta-lactams, 6 aminoglycosides, tetracycline, sulfonamide, trimethoprim, and polymyxin B. Group II (4 strains) was resistant to 11 antibiotics, including 3 beta-lactams, 5 aminoglycosides, sulfonamide, trimethoprim, and polymyxin B. Donors from both groups transferred resistance traits to Escherichia coli. Transconjugants from matings with group II donors all acquired resistance to nine antibiotics, including the three beta-lactams, five aminoglycosides, and sulfonamide. Transconjugants from matings with group I donors were of varied antibiotypes, inheriting resistance to up to 11 of the 13 antibiotics. Resistances to trimethoprim and polymyxin B were never observed to transfer. E. coli transconjugants of each group were capable of transferring multiple-antibiotic resistance to several other members of the family Enterobacteriaceae. All group II S. marcescens and E. coli donors and all group I S. marcescens donors transferred carbenicillin, streptomycin, kanamycin, gentamicin, tobramycin, and sisomicin resistance to Pseudomonas aeruginosa. The results suggest that these S. marcescens strains harbor R factors of a broader host range than previously reported. PMID:106772

  4. Antimicrobial activity of commonly used antibiotics and DNA fingerprint analysis of Pseudomonas aeruginosa obtained from clinical isolates and unchlorinated drinking water in Korea, 2010.

    PubMed

    Kim, Jung Rae; Lee, Do Kyung; An, Hyang Mi; Kim, Mi Jin; Lee, Si Won; Cha, Min Kyeong; Lee, Kang Oh; Ha, Nam Joo

    2011-08-01

    Pseudomonas aeruginosa exists in various environments, and can cause mild or serious infections resulting in a wide range of symptoms. In this study, we collected bacterial isolates from hospitalized patients and unchlorinated drinking water, in Korea, 2010. The water-borne and clinical isolates were compared using colony morphology, antimicrobial susceptibility testing, and random amplification of polymorphic DNA analysis. We first compared morphological features of the water-borne and clinical isolates. The clearest difference in colony morphology was colony shape; five water-borne isolate colonies (83%) had a smooth, circular morphology, while nine (75%) clinical isolate colonies had a rough, irregular morphology. Minimum inhibitory concentrations analyses were performed to determine antimicrobial resistant patterns; using ceftazidime, gentamicin, tigecycline, chloramphenicol, meropenem, and tobramycin according to Clinical and Laboratory Standard Institute (CLSI, 2009) methodology. All waterborne isolates were not resistant to gentamicin, tobramycin, and meropenem. The clinical isolates were resistant to every antibiotic except chloramphenicol. Genotyping was performed using the repetitive extragenic palindromic polymerase-chain-reaction. The DNA fingerprinting patterns did not reveal genetic similarity between the water-borne and clinical P. aeruginosa isolates. On the contrary, they showed that genetically distinct populations have been established in each of these environments. We have revealed significant morphological, clinical and genetic differences between water-borne and clinical isolates of the same bacterial species.

  5. SCL-LCL-PHA copolymer production by a local isolate, Pseudomonas aeruginosa MTCC 7925.

    PubMed

    Singh, Akhilesh Kumar; Mallick, Nirupama

    2009-05-01

    A five-level-four-factor central composite rotary design (CCRD) was employed in combination with response surface methodology (RSM) to optimize the process variables for the production of a novel copolymer consisting of short-chain-length (SCL) and long-chain-length (LCL) PHA units, i.e., P(3HB-3HV-3HHD-3HOD) copolymer in Pseudomonas aeruginosa MTCC 7925. The four variables involved in this study were ethanol, glucose, ammonium nitrate (NH(4)NO(3)), and potassium dihydrogen phosphate (KH(2)PO(4)). A second-order polynomial equation was obtained by multiple regression analysis using RSM. The statistical analyses of the results showed that all the four variables had significant impact on the copolymer yield. The model predicted a maximum yield of 81.1% of dry cell weight (dcw) on setting the concentrations of ethanol and glucose at 1.5 and 1.1%, and KH(2)PO(4) and NH(4)NO(3) at 2.79 and 1.86 g/L, respectively. Verification of the predicted value resulted into a yield of 77.6% (dcw). This novel copolymer exhibited comparable material properties with polypropylene (PP) and low density polyethylene (LDPE), thus advocating its potential applications in various fields.

  6. Prevalence of Extended-Spectrum and Metallo β-Lactamase Production in AmpC β-Lactamase Producing Pseudomonas aeruginosa Isolates From Burns

    PubMed Central

    Rafiee, Roya; Eftekhar, Fereshteh; Tabatabaei, Seyyed Ahmad; Minaee Tehrani, Dariush

    2014-01-01

    Background: Pseudomonas aeruginosa is one of the most common causes of nosocomial infections. Resistance of P. aeruginosa to β-lactam antibiotics may be the result of acquired resistance through mutation and over production of various antibiotic inactivating enzymes. This research aimed to determine the prevalence of extended-spectrum β-lactamases (ESBL) and metallo β-lactamase (MBL) production as well as the presence of their related genes among AmpC β-lactamase producing P. aeruginosa isolated from burns. Objectives: The current study aimed to determine the prevalence of class A ESBL and MBL production in relation to the presence of their related genes among AmpC β-lactamase producing P. aeruginosa isolated from burns. Materials and Methods: The antimicrobial susceptibility of 51 P. aeruginosa isolates from patients with burns was examined against 13 antibiotics by the disc diffusion method. Minimum inhibitory concentrations (MIC) for imipenem and ceftazidime were measured by the microdilution method. AmpC production was detected by AmpC disc and the modified three-dimensional extract tests. ESBL phenotype was confirmed by the double disc synergy test (DDST). Presence of β-lactamase genes was detected by specific primers and polymerase chain reaction (PCR). Results: All isolates were multidrug resistant. AmpC, ESBL and MBL production were observed in 35 (68.6%), 20 (39.2%) and 19 (37.3%) isolates, respectively. Overall, 43 isolates (84.3%) carried β-lactamase genes, out of which 31 (60.8%) harbored blaAmpC, 20 (39.2%) had blaTEM and 11 (21.6%) carried blaPER-1 genes. Among the AmpC producers, two isolates (6.5%) carried blaAmpC + blaESBL, 13 (41.9%) had blaAmpC + blaMBL and six (19.4%) produced the three enzymes. Conclusions: A high prevalence of multiple β-lactamase production was observed among the AmpC producers (60%), of which the majority co-produced AmpC and MBL. The current study results showed correlation between β-lactamase production and the

  7. Comparison of proteins expressed by Pseudomonas aeruginosa strains representing initial and chronic isolates from a cystic fibrosis patient: an analysis by 2-D gel electrophoresis and capillary column liquid chromatography-tandem mass spectrometry.

    PubMed

    Hanna, S L; Sherman, N E; Kinter, M T; Goldberg, J B

    2000-10-01

    Isolates of Pseudomonas aeruginosa from chronic lung infections in cystic fibrosis (CF) patients have phenotypes distinct from those initially infecting CF patients, as well as from other clinical or environmental isolates. To gain a better understanding of the differences in these isolates, protein expression was followed using two-dimensional (2-D) gel electrophoresis and protein identification by peptide sequencing using micro-capillary column liquid chromatography-tandem mass spectrometry (microLC/MS/MS). The isolates selected for this analysis were from the sputum of a CF patient: strain 383 had a nonmucoid phenotype typical of isolates from the environment, and strain 2192, obtained from the same patient, had a mucoid phenotype typical of isolates from chronic CF lung infections. Strains 383 and 2192 were confirmed to be genetically identical by restriction endonuclease analysis, random amplified polymorphic DNA-PCR, and pulsed-field gel electrophoresis. Conditions of protein extraction were optimized for consistent high-resolution separation of several hundred proteins from these clinical isolates as detected by Coomassie staining of 2-D gels. Fourteen proteins were selected for analysis; this group included those whose expression was common between both strains as well as unique for each strain. The proteins were identified by microLC/MS/MS of the peptides produced by an in-gel tryptic digestion and compared to translated data from the Pseudomonas Genome Project; optimization of this technique has allowed for the comparison of proteins expressed by strains 383 and 2192.

  8. Detection of Ambler class A, B and D ß-lactamases among Pseudomonas aeruginosa and Acinetobacter baumannii clinical isolates from burn patients.

    PubMed

    Hakemi Vala, M; Hallajzadeh, M; Hashemi, A; Goudarzi, H; Tarhani, M; Sattarzadeh Tabrizi, M; Bazmi, F

    2014-03-31

    In this study, we evaluated the existence of classes A, B and D ß-lactamases among Pseudomonas aeruginosa (P.aeruginosa) and Acinetobacter baumannii (A.baumannii) strains isolated from burn patients in Tehran during the years 2012 and 2013. From these strains, the frequency of MBL (metallo-beta-lactamase) and ESBL (extended-spectrum beta-lactamase) producers were evaluated using CDDT (Combined Disk Diffusion Tests). The prevalence of some related genes, including blaIMP, blaVIM, blaSPM, blaKPC, blaGIM, blaDIM, blaBIC, blaOXA-48, blaCTX-M-15 and blaNDM genes, was evaluated using PCR and sequencing methods. Of the 75 non-fermenter isolates, 47 P.aeruginosa and 28 A.baumannii were isolated and identified. A high rate of resistance to common antibiotics was detected among A.baumannii isolates in particular, showing 100% resistance to 9 tested antibiotics. CDDT showed that 21 (28%) and 25 (34.25%) of the non-fermenter isolates were ESBL and MBL producers respectively. The prevalence of blaCTX-M-15 and blaIMP genes among the 75 non-fermenter isolates was 7 (9.3%) and 1 (1.3%), respectively. Fortunately, no other genes were detected in either of the non-fermenters. The mortality rate due to MBL-producing isolates was 5 (20%). This study showed specific resistance genes exist among some MBL and ESBL gram-negative non-fermenters which were isolated from burn patients in Tehran.

  9. Waste Isolation Pilot Plant Annual Site Environmental Report for 2012

    SciTech Connect

    2013-09-01

    The purpose of the Waste Isolation Pilot Plant (WIPP) Annual Site Environmental Report for 2012 (ASER) is to provide information required by U.S. Department of Energy (DOE) Order 231.1B, Environment, Safety, and Health Reporting. Specifically, the ASER presents summary environmental data to: Characterize site environmental management performance; Summarize environmental occurrences and responses reported during the calendar year; Confirm compliance with environmental standards and requirements; Highlight significant environmental accomplishments, including progress toward the DOE Environmental Sustainability Goals made through implementation of the WIPP Environmental Management System (EMS).

  10. Pharmacodynamics of Aerosolized Fosfomycin and Amikacin against Resistant Clinical Isolates of Pseudomonas aeruginosa and Klebsiella pneumoniae in a Hollow-Fiber Infection Model: Experimental Basis for Combination Therapy

    PubMed Central

    Sime, Fekade Bruck; Johnson, Adam; Whalley, Sarah; Santoyo-Castelazo, Anahi; Montgomery, A. Bruce; Walters, Kathie Ann; Lipman, Jeffrey; Hope, William W.

    2016-01-01

    ABSTRACT There has been a resurgence of interest in aerosolization of antibiotics for treatment of patients with severe pneumonia caused by multidrug-resistant pathogens. A combination formulation of amikacin-fosfomycin is currently undergoing clinical testing although the exposure-response relationships of these drugs have not been fully characterized. The aim of this study was to describe the individual and combined antibacterial effects of simulated epithelial lining fluid exposures of aerosolized amikacin and fosfomycin against resistant clinical isolates of Pseudomonas aeruginosa (MICs of 16 mg/liter and 64 mg/liter) and Klebsiella pneumoniae (MICs of 2 mg/liter and 64 mg/liter) using a dynamic hollow-fiber infection model over 7 days. Targeted peak concentrations of 300 mg/liter amikacin and/or 1,200 mg/liter fosfomycin as a 12-hourly dosing regimens were used. Quantitative cultures were performed to describe changes in concentrations of the total and resistant bacterial populations. The targeted starting inoculum was 108 CFU/ml for both strains. We observed that neither amikacin nor fosfomycin monotherapy was bactericidal against P. aeruginosa while both were associated with rapid amplification of resistant P. aeruginosa strains (about 108 to 109 CFU/ml within 24 to 48 h). For K. pneumoniae, amikacin but not fosfomycin was bactericidal. When both drugs were combined, a rapid killing was observed for P. aeruginosa and K. pneumoniae (6-log kill within 24 h). Furthermore, the combination of amikacin and fosfomycin effectively suppressed growth of resistant strains of P. aeruginosa and K. pneumoniae. In conclusion, the combination of amikacin and fosfomycin was effective at maximizing bacterial killing and suppressing emergence of resistance against these clinical isolates. PMID:27795380

  11. Mutational and acquired carbapenem resistance mechanisms in multidrug resistant Pseudomonas aeruginosa clinical isolates from Recife, Brazil

    PubMed Central

    Cavalcanti, Felipe Lira de Sá; Mirones, Cristina Rodríguez; Paucar, Elena Román; Montes, Laura Álvarez; Leal-Balbino, Tereza Cristina; de Morais, Marcia Maria Camargo; Martínez-Martínez, Luis; Ocampo-Sosa, Alain Antonio

    2015-01-01

    An investigation was carried out into the genetic mechanisms responsible for multidrug resistance in nine carbapenem-resistant Pseudomonas aeruginosaisolates from different hospitals in Recife, Brazil. Susceptibility to antimicrobial agents was determined by broth microdilution. Polymerase chain reaction (PCR) was employed to detect the presence of genes encoding β-lactamases, aminoglycoside-modifying enzymes (AMEs), 16S rRNA methylases, integron-related genes and OprD. Expression of genes coding for efflux pumps and AmpC cephalosporinase were assessed by quantitative PCR. The outer membrane proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The blaSPM-1, blaKPC-2 and blaGES-1 genes were detected in P. aeruginosaisolates in addition to different AME genes. The loss of OprD in nine isolates was mainly due to frameshift mutations, premature stop codons and point mutations. An association of loss of OprD with the overexpression of MexAB-OprM and MexXY-OprM was observed in most isolates. Hyper-production of AmpC was also observed in three isolates. Clonal relationship of the isolates was determined by repetitive element palindromic-PCR and multilocus sequence typing. Our results show that the loss of OprD along with overexpression of efflux pumps and β-lactamase production were responsible for the multidrug resistance in the isolates analysed. PMID:26676375

  12. Complete Genome Sequences of Four Extensively Drug-Resistant Pseudomonas aeruginosa Strains, Isolated from Adults with Ventilator-Associated Pneumonia at a Tertiary Referral Hospital in Mexico City.

    PubMed

    Espinosa-Camacho, Luis F; Delgado, Gabriela; Soberón-Chávez, Gloria; Alcaraz, Luis D; Castañon, Jorge; Morales-Espinosa, Rosario

    2017-09-07

    Four extensively drug-resistant Pseudomonas aeruginosa strains, isolated from patients with pneumonia, were sequenced using PacBio RS-II single-molecule real-time (SMRT) technology. Genome sequence analysis identified great variability among mobile genetic elements, as well as some previously undescribed genomic islands and new variants of class 1 integrons (In1402, In1403, In1404, and In1408). Copyright © 2017 Espinosa-Camacho et al.

  13. Detection of blaVIM-7 in an extensively drug-resistant Pseudomonas aeruginosa isolate belonging to ST1284 in Brazil.

    PubMed

    Balero de Paula, Suelen; Cayô, Rodrigo; Streling, Ana Paula; Silva Nodari, Carolina; Pereira Matos, Adriana; Eches Perugini, Marcia Regina; Gales, Ana Cristina; Carrara-Marroni, Floristher Elaine; Yamada-Ogatta, Sueli F

    2017-09-01

    We described for the first time an extensively drug-resistant Pseudomonas aeruginosa isolate belonging to ST1284 carrying a plasmid-mediated blaVIM-7 in Brazil. The blaVIM-7 was harbored by an integron that also carried aacA4 and blaOXA-46. Multiple virulence factors were also detected. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Synergistic activities of macrolide antibiotics against Pseudomonas aeruginosa, Burkholderia cepacia, Stenotrophomonas maltophilia, and Alcaligenes xylosoxidans isolated from patients with cystic fibrosis.

    PubMed

    Saiman, Lisa; Chen, Yunhua; Gabriel, Pablo San; Knirsch, Charles

    2002-04-01

    Azithromycin and clarithromycin were paired with other antibiotics to test synergistic activity against 300 multidrug-resistant pathogens isolated from cystic fibrosis (CF) patients. Clarithromycin-tobramycin was most active against Pseudomonas aeruginosa and inhibited 58% of strains. Azithromycin-trimethoprim-sulfamethoxazole, azithromycin-ceftazidime, and azithromycin-doxycycline or azithromycin-trimethoprim-sulfamethoxazole inhibited 40, 20, and 22% of Stenotrophomonas maltophilia, Burkholderia cepacia complex, and Achromobacter (Alcaligenes) xylosoxidans strains, respectively.

  15. Extensively drug-resistant pseudomonas aeruginosa isolates containing blaVIM-2 and elements of Salmonella genomic island 2: a new genetic resistance determinant in Northeast Ohio.

    PubMed

    Perez, Federico; Hujer, Andrea M; Marshall, Steven H; Ray, Amy J; Rather, Philip N; Suwantarat, Nuntra; Dumford, Donald; O'Shea, Patrick; Domitrovic, T Nicholas J; Salata, Robert A; Chavda, Kalyan D; Chen, Liang; Kreiswirth, Barry N; Vila, Alejandro J; Haussler, Susanne; Jacobs, Michael R; Bonomo, Robert A

    2014-10-01

    Carbapenems are a mainstay of treatment for infections caused by Pseudomonas aeruginosa. Carbapenem resistance mediated by metallo-β-lactamases (MBLs) remains uncommon in the United States, despite the worldwide emergence of this group of enzymes. Between March 2012 and May 2013, we detected MBL-producing P. aeruginosa in a university-affiliated health care system in northeast Ohio. We examined the clinical characteristics and outcomes of patients, defined the resistance determinants and structure of the genetic element harboring the blaMBL gene through genome sequencing, and typed MBL-producing P. aeruginosa isolates using pulsed-field gel electrophoresis (PFGE), repetitive sequence-based PCR (rep-PCR), and multilocus sequence typing (MLST). Seven patients were affected that were hospitalized at three community hospitals, a long-term-care facility, and a tertiary care center; one of the patients died as a result of infection. Isolates belonged to sequence type 233 (ST233) and were extensively drug resistant (XDR), including resistance to all fluoroquinolones, aminoglycosides, and β-lactams; two isolates were nonsusceptible to colistin. The blaMBL gene was identified as blaVIM-2 contained within a class 1 integron (In559), similar to the cassette array previously detected in isolates from Norway, Russia, Taiwan, and Chicago, IL. Genomic sequencing and assembly revealed that In559 was part of a novel 35-kb region that also included a Tn501-like transposon and Salmonella genomic island 2 (SGI2)-homologous sequences. This analysis of XDR strains producing VIM-2 from northeast Ohio revealed a novel recombination event between Salmonella and P. aeruginosa, heralding a new antibiotic resistance threat in this region's health care system.

  16. Pseudomonas aeruginosa sepsis in stem cell transplantation patients.

    PubMed

    Fanci, Rosa; Pecile, Patrizia; Casalone, Enrico; Mengoni, Alessio; Tamburini, Elena; Guidi, Stefano; Cecconi, Daniela; Bosi, Alberto; Nicoletti, Pierluigi; Mastromei, Giorgio

    2006-07-01

    We report the epidemiological investigation of an outbreak of Pseudomonas aeruginosa infection in 6 patients who shared, during different periods, the same 2 rooms of a bone marrow transplantation unit. Phenotypic and molecular analysis of isolates from patients and from the environment strongly suggested a single, environmental source of infection.

  17. In vitro comparison of the effectiveness of polihexanide and chlorhexidine against canine isolates of Staphylococcus pseudintermedius, Pseudomonas aeruginosa and Malassezia pachydermatis.

    PubMed

    Banovic, Frane; Bozic, Frane; Lemo, Niksa

    2013-08-01

    Polihexanide (polyhexamethylene biguanide) is an antiseptic substance that plays a prominent role in the treatment of critically colonized or infected acute and chronic wounds in humans. The aim of this study was to assess the in vitro antimicrobial efficacy of polihexanide against canine isolates of Staphylococcus pseudintermedius, Pseudomonas aeruginosa and Malassezia pachydermatis and compare it with 4.5% chlorhexidine digluconate for two different contact times. Ten isolates of each organism were incubated at 37°C for 3 and 5 min, respectively, with each antiseptic diluted 1:2 to 1:4096 in phosphate-buffered saline. Both products showed excellent antimicrobial activity against all isolates tested. No significant differences in antimicrobial efficacy between antiseptics for all isolates were found. With the exception of one isolate of M. pachydermatis at 3 min exposure time, all isolates were completely killed by a dilution of 1:32 of polihexanide as well as chlorhexidine at both exposure times. Although the mean values of break-point concentrations for both antiseptics increased with the longer exposure time of 5 min, there were no significant differences between the two exposure times. The P. aeruginosa isolates were more susceptible than S. pseudintermedius for both antiseptics, and break-point dilutions were significantly higher compared with break-point dilutions obtained by all other treatments. The results indicate that polihexanide has comparable in vitro antimicrobial efficacy to chlorhexidine and presents a potential alternative agent for skin and wound antisepsis in veterinary medicine. © 2013 ESVD and ACVD.

  18. Pseudomonas aeruginosa Population Structure Revisited

    PubMed Central

    Pirnay, Jean-Paul; Bilocq, Florence; Pot, Bruno; Cornelis, Pierre; Zizi, Martin; Van Eldere, Johan; Deschaght, Pieter; Vaneechoutte, Mario; Jennes, Serge; Pitt, Tyrone; De Vos, Daniel

    2009-01-01

    At present there are strong indications that Pseudomonas aeruginosa exhibits an epidemic population structure; clinical isolates are indistinguishable from environmental isolates, and they do not exhibit a specific (disease) habitat selection. However, some important issues, such as the worldwide emergence of highly transmissible P. aeruginosa clones among cystic fibrosis (CF) patients and the spread and persistence of multidrug resistant (MDR) strains in hospital wards with high antibiotic pressure, remain contentious. To further investigate the population structure of P. aeruginosa, eight parameters were analyzed and combined for 328 unrelated isolates, collected over the last 125 years from 69 localities in 30 countries on five continents, from diverse clinical (human and animal) and environmental habitats. The analysed parameters were: i) O serotype, ii) Fluorescent Amplified-Fragment Length Polymorphism (FALFP) pattern, nucleotide sequences of outer membrane protein genes, iii) oprI, iv) oprL, v) oprD, vi) pyoverdine receptor gene profile (fpvA type and fpvB prevalence), and prevalence of vii) exoenzyme genes exoS and exoU and viii) group I pilin glycosyltransferase gene tfpO. These traits were combined and analysed using biological data analysis software and visualized in the form of a minimum spanning tree (MST). We revealed a network of relationships between all analyzed parameters and non-congruence between experiments. At the same time we observed several conserved clones, characterized by an almost identical data set. These observations confirm the nonclonal epidemic population structure of P. aeruginosa, a superficially clonal structure with frequent recombinations, in which occasionally highly successful epidemic clones arise. One of these clones is the renown and widespread MDR serotype O12 clone. On the other hand, we found no evidence for a widespread CF transmissible clone. All but one of the 43 analysed CF strains belonged to a ubiquitous P

  19. Isolation of Pseudomonas aeruginosa strains from dental office environments and units in Barretos, state of São Paulo, Brazil, and analysis of their susceptibility to antimicrobial drugs

    PubMed Central

    de Oliveira, Ana Claudia; Maluta, Renato Pariz; Stella, Ariel Eurides; Rigobelo, Everlon Cid; Marin, José Moacir; de Ávila, Fernando Antonio

    2008-01-01

    A wide variety of opportunistic pathogens has been detected in the tubing supplying water to odontological equipment, in special in the biofilm lining of these tubes. Among these pathogens, Pseudomonas aeruginosa, one of the leading causes of nosocomial infections, is frequently found in water lines supplying dental units. In the present work, 160 samples of water, and 200 fomite samples from forty dental units were collected in the city of Barretos, State of São Paulo, Brazil and evaluated between January and July, 2005. Seventy-six P. aeruginosa strains, isolated from the dental environment (5 strains) and water system (71 strains), were tested for susceptibility to six antimicrobial drugs most frequently used against P. aeruginosa infections. Susceptibility to ciprofloxacin, followed by meropenem was the predominant profile. The need for effective means of reducing the microbial burden within dental unit water lines is emphasized, and the risk of exposure and cross-infection in dental practice, in special when caused by opportunistic pathogens like P. aeruginosa, are highlighted. PMID:24031269

  20. Contribution of efflux pumps in fluroquinolone resistance in multi-drug resistant nosocomial isolates of Pseudomanas aeruginosa from a tertiary referral hospital in north east India.

    PubMed

    Choudhury, D; Talukdar, A Das; Maurya, A P; Choudhury, M Dutta; Dhar Chanda, D; Chakravarty, A; Bhattacharjee, A

    2015-01-01

    Pseudomonas aeruginosa is one of the leading opportunistic pathogen and its ability to acquire resistance against series of antimicrobial agents confine treatment option for nosocomial infections. Increasing resistance to fluroquinolone (FQ) agents has further worsened the scenario. The major mechanism of resistance to FQs includes mutation in FQs target genes in bacteria (DNA gyrase and/or topoisomerases) and overexpression of antibiotic efflux pumps. We have investigated the role of efflux pump mediated FQ resistance in nosocomial isolates of P. aeruginosa from a tertiary referral hospital in north eastern part of India. A total of 234 non-duplicate, consecutive clinical isolates of P. aeruginosa were obtained from a tertiary referral hospital of north-east India. An efflux pump inhibitor (EPI), carbonyl cyanide m-chlorophenylhydrazone (CCCP) based method was used for determination of efflux pump activity and multiplex polymerase chain reaction (PCR) was performed for molecular characterisation of efflux pump. Minimum inhibitory concentration (MIC) reduction assay was also performed for all the isolates. A total number of 56 (23%) have shown efflux mediated FQ resistance. MexAB-OprM efflux system was predominant type. This is the first report of efflux pump mediated FQ resistance from this part of the world and the continued emergence of these mutants with such high MIC range from this part of the world demands serious awareness, diagnostic intervention, and proper therapeutic option.

  1. Anti-biofilm activity of biogenic selenium nanoparticles and selenium dioxide against clinical isolates of Staphylococcus aureus, Pseudomonas aeruginosa, and Proteus mirabilis.

    PubMed

    Shakibaie, Mojtaba; Forootanfar, Hamid; Golkari, Yaser; Mohammadi-Khorsand, Tayebe; Shakibaie, Mohammad Reza

    2015-01-01

    The aim of the present study was to investigate the anti-biofilm activity of biologically synthesized selenium nanoparticles (Se NPs) against the biofilm produced by clinically isolated bacterial strains compared to that of selenium dioxide. Thirty strains of Staphylococcus aureus, Pseudomonas aeruginosa, and Proteus mirabilis were isolated from various specimens of the patients hospitalized in different hospitals (Kerman, Iran). Quantification of the biofilm using microtiter plate assay method introduced 30% of S. aureus, 13% of P. aeruginosa and 17% of P. mirabilis isolates as severely adherent strains. Transmission electron micrograph (TEM) of the purified Se NPs (produced by Bacillus sp. MSh-1) showed individual and spherical nano-structure in the size range of 80-220nm. Obtained results of the biofilm formation revealed that selenium nanoparticles inhibited the biofilm of S. aureus, P. aeruginosa, and P. mirabilis by 42%, 34.3%, and 53.4%, respectively, compared to that of the non-treated samples. Effect of temperature and pH on the biofilm formation in the presence of Se NPs and SeO2 was also evaluated.

  2. Structural and physicochemical characterization of crude biosurfactant produced by Pseudomonas aeruginosa SP4 isolated from petroleum-contaminated soil.

    PubMed

    Pornsunthorntawee, Orathai; Wongpanit, Panya; Chavadej, Sumaeth; Abe, Masahiko; Rujiravanit, Ratana

    2008-04-01

    Pseudomonas aeruginosa strain SP4, isolated from petroleum-contaminated soil in Thailand, was used to produce a biosurfactant from a nutrient broth with palm oil as the carbon source. The key components of the crude biosurfactant were fractionated by using HPLC-ELSD technique. With the use of ATR-FTIR spectroscopy, in combination with (1)H NMR and MS analyses, chemical structures of the fractionated components of the crude biosurfactant were identified as rhamnolipid species. When compared to synthetic surfactants, including Pluronic F-68, which is a triblock nonionic surfactant containing poly(ethylene oxide) and poly(propylene oxide), and sodium dodecyl sulfate, the crude biosurfactant showed comparable physicochemical properties, in terms of the surface activities. The crude biosurfactant reduced the surface tension of pure water to 29.0 mN/m with a critical micelle concentration of approximately 200 mg/l, and it exhibited good thermal and pH stability. The crude biosurfactant also formed stable water-in-oil microemulsions with crude oil and various types of vegetable oils, but not with short-chain hydrocarbons.

  3. Antibacterial compound produced by Pseudomonas aeruginosa strain UICC B-40, an endophytic bacterium isolated from Neesia altissima.

    PubMed

    Pratiwi, Rina Hidayati; Hidayat, Iman; Hanafi, Muhammad; Mangunwardoyo, Wibowo

    2017-04-01

    This study's aim was to determine the identity of antibacterial compounds produced by Pseudomonas aeruginosa strain UICC B-40 and describe the antibacterial compounds' mechanisms of action for damaging pathogenic bacteria cells. Isolation and identification of the compounds were carried out using thin layer chromatography (TLC), nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography mass spectrometry (LC-MS) analyses. Antibacterial activity was assayed via minimum inhibitory concentration (MIC) and the antibacterial compound mechanism was observed morphologically through scanning electron microscopy (SEM). This study successfully identified the (2E,5E)-phenyltetradeca-2,5-dienoate antibacterial compound (molecular weight 300 g/mol), composed of a phenolic ester, fatty acid and long chain of aliphatic group structures. MIC values for this compound were determined at 62.5 μg/ml against Staphylococcus aureus strain ATCC 25923. The mechanism of the compound involved breaking down the bacterial cell walls through the lysis process. The (2E,5E)-phenyltetradeca-2,5-dienoate compound exhibited inhibitory activity on the growth of Gram-positive bacteria.

  4. [Clinical isolates of Pseudomonas aeruginosa producers of extended spectrum beta-lactamases at a private institution in Cordoba].

    PubMed

    Piersigilli, Andrea L; Enrico, M Cecilia; Bongiovanni, M Eugenia; Bilbao, Liliana E; Martínez, Gustavo; Ledesma, Elizabeth M

    2009-08-01

    Extended spectrum beta-lactamases (ESBL) are capable of inhibiting the action of extended spectrum cephalosporins and monobactams. The objective of this work is to describe six isolates of ESBL producing Pseudomonas aeruginosa, retrieved from intensive care patients. The susceptibility test was performed by diffusion. For the phenotypic detection of ESBL, the following was assessed: the difference between ceftazidime ceftazidime/clavulanic acid (CAZ-CAC) and the synergy between imipenem-ceftazidime (IMI-CAZ) and cefepime-ceftazidime/clavulanic acid -ceftazidime (FEP-CAC-CAZ). The presence of metallo-beta-lactamases (MBL) was discarded through the double disc imipenem-EDTA/mercaptoacetic-meropenem (IMI-EDTA/SMA-MER) method. Molecular characterization of ESBL was performed by polymerase chain reaction (PCR) with blaGES primers. Synergy IMI-CAZ was observed in the studied strains; ESBL type GES was confirmed in five of them. The strategic location of the discs and the evaluation of alert signals for the detection of ESBL is essential, thus contributing to the correct recommendation of treatment in the clinical report.

  5. The Effects of Berberine and Palmatine on Efflux Pumps Inhibition with Different Gene Patterns in Pseudomonas aeruginosa Isolated from Burn Infections

    PubMed Central

    Aghayan, Seyed Sajjad; Kalalian Mogadam, Hamidreza; Fazli, Mozhgan; Darban-Sarokhalil, Davood; Khoramrooz, Seyed Sajjad; Jabalameli, Fereshteh; Yaslianifard, Somayeh; Mirzaii, Mehdi

    2017-01-01

    Background: Related Multidrug Resistance (MDR) to efflux pumps is a significant problem in treating infections caused by Pseudomonas aeruginosa (P. aeruginosa). Plant compounds have been identified as Pump Inhibitors (EPIs). In the current study, the potential effect of Berberine and Palmatine as EPIs were investigated on efflux pump inhibition through focusing on different gene patterns in P. aeruginosa isolated from burn infections. Methods: All isolates were collected and identified using the standard biochemical tests. Antimicrobial sensitivity was performed based on disk agar diffusion method for 12 antibiotics. MIC-MBC tests were also performed based on the broth microdilution method to detect synergistic relationship between ciprofloxacin, Berberine and Palmatine. Detection of mexA, mexB, mexC, mexD, mexE, mexF and mexX was conducted by PCR assay. Fisher’s Exact test and Logistic Regression were used as statistical tools. Results: A total of 60 P. aeruginosa isolates were collected. The highest and lowest levels of resistance were found to be respectively against clindamycin and tigecycline. Comparing the MIC with MBC distribution, it was found that Berberine and Palmatine lower the MIC-MBC level of ciprofloxacin. The PCR results indicated that the highest frequency is about MexAB-OprM operon. The statistical analysis among different gene patterns of efflux pumps showed that there were no significant relationships between the effectiveness of Berberine and Palmatine (p>0.05). Conclusion: It can be speculated that Berberine and Palmatine both act as EPIs and can be used as auxiliary treatments with the purpose of increasing the effect of available antibiotics as well as decreasing the emergence of MDR bacteria. The efficiency of these combinations should be studied further under in vivo conditions to have a more comprehensive conclusion regarding this issue. PMID:28090273

  6. D-amino acids enhance the activity of antimicrobials against biofilms of clinical wound isolates of Staphylococcus aureus and Pseudomonas aeruginosa.

    PubMed

    Sanchez, Carlos J; Akers, Kevin S; Romano, Desiree R; Woodbury, Ronald L; Hardy, Sharanda K; Murray, Clinton K; Wenke, Joseph C

    2014-08-01

    Within wounds, microorganisms predominantly exist as biofilms. Biofilms are associated with chronic infections and represent a tremendous clinical challenge. As antibiotics are often ineffective against biofilms, use of dispersal agents as adjunctive, topical therapies for the treatment of wound infections involving biofilms has gained interest. We evaluated in vitro the dispersive activity of D-amino acids (D-AAs) on biofilms from clinical wound isolates of Staphylococcus aureus and Pseudomonas aeruginosa; moreover, we determined whether combinations of D-AAs and antibiotics (clindamycin, cefazolin, oxacillin, rifampin, and vancomycin for S. aureus and amikacin, colistin, ciprofloxacin, imipenem, and ceftazidime for P. aeruginosa) enhance activity against biofilms. D-Met, D-Phe, and D-Trp at concentrations of ≥ 5 mM effectively dispersed preformed biofilms of S. aureus and P. aeruginosa clinical isolates, an effect that was enhanced when they were combined as an equimolar mixture (D-Met/D-Phe/D-Trp). When combined with D-AAs, the activity of rifampin was significantly enhanced against biofilms of clinical isolates of S. aureus, as indicated by a reduction in the minimum biofilm inhibitory concentration (MBIC) (from 32 to 8 μg/ml) and a >2-log reduction of viable biofilm bacteria compared to treatment with antibiotic alone. The addition of D-AAs was also observed to enhance the activity of colistin and ciprofloxacin against biofilms of P. aeruginosa, reducing the observed MBIC and the number of viable bacteria by >2 logs and 1 log at 64 and 32 μg/ml in contrast to antibiotics alone. These findings indicate that the biofilm dispersal activity of D-AAs may represent an effective strategy, in combination with antimicrobials, to release bacteria from biofilms, subsequently enhancing antimicrobial activity.

  7. d-Amino Acids Enhance the Activity of Antimicrobials against Biofilms of Clinical Wound Isolates of Staphylococcus aureus and Pseudomonas aeruginosa

    PubMed Central

    Akers, Kevin S.; Romano, Desiree R.; Woodbury, Ronald L.; Hardy, Sharanda K.; Murray, Clinton K.; Wenke, Joseph C.

    2014-01-01

    Within wounds, microorganisms predominantly exist as biofilms. Biofilms are associated with chronic infections and represent a tremendous clinical challenge. As antibiotics are often ineffective against biofilms, use of dispersal agents as adjunctive, topical therapies for the treatment of wound infections involving biofilms has gained interest. We evaluated in vitro the dispersive activity of d-amino acids (d-AAs) on biofilms from clinical wound isolates of Staphylococcus aureus and Pseudomonas aeruginosa; moreover, we determined whether combinations of d-AAs and antibiotics (clindamycin, cefazolin, oxacillin, rifampin, and vancomycin for S. aureus and amikacin, colistin, ciprofloxacin, imipenem, and ceftazidime for P. aeruginosa) enhance activity against biofilms. d-Met, d-Phe, and d-Trp at concentrations of ≥5 mM effectively dispersed preformed biofilms of S. aureus and P. aeruginosa clinical isolates, an effect that was enhanced when they were combined as an equimolar mixture (d-Met/d-Phe/d-Trp). When combined with d-AAs, the activity of rifampin was significantly enhanced against biofilms of clinical isolates of S. aureus, as indicated by a reduction in the minimum biofilm inhibitory concentration (MBIC) (from 32 to 8 μg/ml) and a >2-log reduction of viable biofilm bacteria compared to treatment with antibiotic alone. The addition of d-AAs was also observed to enhance the activity of colistin and ciprofloxacin against biofilms of P. aeruginosa, reducing the observed MBIC and the number of viable bacteria by >2 logs and 1 log at 64 and 32 μg/ml in contrast to antibiotics alone. These findings indicate that the biofilm dispersal activity of d-AAs may represent an effective strategy, in combination with antimicrobials, to release bacteria from biofilms, subsequently enhancing antimicrobial activity. PMID:24841260

  8. Reduction of fluoroquinolone use is associated with a decrease in methicillin-resistant Staphylococcus aureus and fluoroquinolone-resistant Pseudomonas aeruginosa isolation rates: a 10 year study.

    PubMed

    Lafaurie, Matthieu; Porcher, Raphael; Donay, Jean-Luc; Touratier, Sophie; Molina, Jean-Michel

    2012-04-01

    High rates of methicillin-resistant Staphylococcus aureus (MRSA) and fluoroquinolone-resistant Pseudomonas aeruginosa may be related, in part, to the overuse of fluoroquinolones. The objective was to analyse and correlate long-term surveillance data on MRSA and fluoroquinolone-resistant P. aeruginosa rates and antibiotic consumption after implementation of an institution-wide programme to reduce fluoroquinolone use. An interrupted time series/quasi-experimental study of monthly fluoroquinolone use and MRSA and fluoroquinolone-resistant P. aeruginosa isolation rates was carried out in a tertiary hospital during three periods: pre-intervention (January 2000-August 2005), intervention (September 2005-March 2006), and post-intervention (March 2006-March 2010). The effect of the intervention on the consumption of fluoroquinolones and bacterial resistance was assessed using segmented regression analyses. Mean monthly fluoroquinolone consumption dropped by 29.1 defined daily doses per 1000 patient-days (DDD/1000 PD) (95% CI 13.1-45.9; P = 0.0005) from a mean of 148.2 to 119.1 DDD/1000 PD during the intervention period. A sustained and significant decrease in fluoroquinolone consumption of -0.95 DDD/1000 PD/month was also observed during the post-intervention period (P = 0.0002). During the post-intervention period the rate of fluoroquinolone-resistant P. aeruginosa continuously decreased, from a mean of 42% to 26%, with a constant relative change rate of -13%/year (95% CI -19 to -5, P = 0.001). A decrease in the MRSA rate was observed during the intervention period, from a mean resistance rate of 27% to 21% (P < 0.0001). We showed the sustained impact of a fluoroquinolone control programme on the reduction of fluoroquinolone use with a significant decrease in fluoroquinolone-resistant P. aeruginosa and MRSA rates over 4 years.

  9. Responses of enzymatic antioxidants and non-enzymatic antioxidants in the cyanobacterium Microcystis aeruginosa to the allelochemical ethyl 2-methyl acetoacetate (EMA) isolated from reed (Phragmites communis).

    PubMed

    Hong, Yu; Hu, Hong-Ying; Xie, Xing; Li, Feng-Min

    2008-08-25

    Macrophytic allelochemicals are considered an environment-friendly and promising alternative to control algal bloom. However, studies examining the potential mechanisms of inhibitory allelochemicals on algae are few. The allelochemical ethyl 2-methyl acetoacetate (EMA), isolated from reed (Phragmites communis), was a strong allelopathic inhibitor on the growth of Microcystis aeruginosa. EMA-induced antioxidant responses were investigated in the cyanobacterium M. aeruginosa to understand the mechanism of EMA inhibition on algal growth. The activities of enzymatic antioxidants superoxide dismutase (SOD) and catalase (CAT), and the contents of non-enzymatic antioxidants reduced glutathione (GSH) and ascorbic acid (AsA) of M. aeruginosa cells were analyzed after treatments with different concentrations of EMA. Exposure of M. aeruginosa to EMA caused changes in enzyme activities and contents of non-enzymatic antioxidants in different manners. The decrease in SOD activity occurred first after 4 h of EMA exposure, and more markedly after 40 h. CAT activity did not change after 4 h of EMA exposure, but increased obviously after 40 h. The contents of AsA and GSH were increased greatly by EMA after 4 h. After 60 h, low EMA concentrations still increased the CAT activity and the contents of AsA and GSH, but high EMA concentrations started to impose a marked suppression on them. EMA increased dehydroascorbate (DHAsA) and oxidized glutathione (GSSG) contents during all exposure times. After 60 h, the regeneration rates of AsA and GSH (represented by the AsA/DHAsA ratio and GSH/GSSG ratio, respectively) were reduced by high EMA concentrations. These results suggest that the activation of CAT and the availability of AsA and GSH at early exposure are important to counteract the oxidative stress induced by EMA, and the inactivation of SOD may be crucial to the growth inhibition of M. aeruginosa by EMA.

  10. 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.

  11. IMP-51, a novel IMP-type metallo-β-lactamase with increased doripenem- and meropenem-hydrolyzing activities, in a carbapenem-resistant Pseudomonas aeruginosa clinical isolate.

    PubMed

    Tada, Tatsuya; Nhung, Pham Hong; Miyoshi-Akiyama, Tohru; Shimada, Kayo; Phuong, Doan Mai; Anh, Nguyen Quoc; Ohmagari, Norio; Kirikae, Teruo

    2015-11-01

    A meropenem-resistant Pseudomonas aeruginosa isolate was obtained from a patient in a medical setting in Hanoi, Vietnam. The isolate was found to have a novel IMP-type metallo-β-lactamase, IMP-51, which differed from IMP-7 by an amino acid substitution (Ser262Gly). Escherichia coli expressing blaIMP-51 showed greater resistance to cefoxitin, meropenem, and moxalactam than E. coli expressing blaIMP-7. The amino acid residue at position 262 was located near the active site, proximal to the H263 Zn(II) ligand. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  12. Identification of plasmid OXA and other β-lactamase genes among carbapenem-resistant isolates of Pseudomonas aeruginosa from the Clinical University Hospital in northeastern Poland.

    PubMed

    Sacha, Paweł; Michalska, Anna; Ojdana, Dominika; Wieczorek, Piotr; Hauschild, Tomasz; Majewski, Piotr; Tryniszewska, Elżbieta

    2015-04-01

    The aim of the study was to evaluate the prevalence of OXA and other β-lactamase genes, antibiotic susceptibility, and the genetic relatedness among clinical isolates of P. aeruginosa resistant to carbapenems. The presence of bla- OXA genes was demonstrated in 48% of isolates belonging to four PFGE profiles. Most of them contained the blaOXA-2 gene (88.3%). Other blaOXA genes (Ps1310 with blaOXA-30 and Ps1309 with blaOXA-10) were found in only two isolates. The tested isolates also contained other β-lactamase genes such as blaVIM-2, blaVIM-4, blaSHV-5, and blaTEM-1. All isolates were susceptible only to colistin (100%).

  13. Unexpected challenges in treating multidrug-resistant Gram-negative bacteria: resistance to ceftazidime-avibactam in archived isolates of Pseudomonas aeruginosa.

    PubMed

    Winkler, Marisa L; Papp-Wallace, Krisztina M; Hujer, Andrea M; Domitrovic, T Nicholas; Hujer, Kristine M; Hurless, Kelly N; Tuohy, Marion; Hall, Geraldine; Bonomo, Robert A

    2015-02-01

    Pseudomonas aeruginosa is a notoriously difficult-to-treat pathogen that is a common cause of severe nosocomial infections. Investigating a collection of β-lactam-resistant P. aeruginosa clinical isolates from a decade ago, we uncovered resistance to ceftazidime-avibactam, a novel β-lactam/β-lactamase inhibitor combination. The isolates were systematically analyzed through a variety of genetic, biochemical, genomic, and microbiological methods to understand how resistance manifests to a unique drug combination that is not yet clinically released. We discovered that avibactam was able to inactivate different AmpC β-lactamase enzymes and that blaPDC regulatory elements and penicillin-binding protein differences did not contribute in a major way to resistance. By using carefully selected combinations of antimicrobial agents, we deduced that the greatest barrier to ceftazidime-avibactam is membrane permeability and drug efflux. To overcome the constellation of resistance determinants, we show that a combination of antimicrobial agents (ceftazidime/avibactam/fosfomycin) targeting multiple cell wall synthetic pathways can restore susceptibility. In P. aeruginosa, efflux, as a general mechanism of resistance, may pose the greatest challenge to future antibiotic development. Our unexpected findings create concern that even the development of antimicrobial agents targeted for the treatment of multidrug-resistant bacteria may encounter clinically important resistance. Antibiotic therapy in the future must consider these factors. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  14. Overproduction of active efflux pump and variations of OprD dominate in imipenem-resistant Pseudomonas aeruginosa isolated from patients with bloodstream infections in Taiwan.

    PubMed

    Kao, Cheng-Yen; Chen, Shu-Sheng; Hung, Kuei-Hsiang; Wu, Hsiu-Mei; Hsueh, Po-Ren; Yan, Jing-Jou; Wu, Jiunn-Jong

    2016-06-13

    The emergence of imipenem-resistant Pseudomonas aeruginosa (IRPA) has become a great concern worldwide. The aim of this study was to investigate resistance mechanisms associated with bloodstream isolated IRPA strains in Taiwan. A total of 78 non-duplicated IRPA isolates were isolated from patients with bloodstream infection. The average prevalence of imipenem-resistance in those isolates was 5.9 % during a 10-year longitudinal surveillance in Taiwan. PFGE results showed high clonal diversity among the 78 isolates. VIM-2, VIM-3, OXA-10, and OXA-17 β-lactamases were identified in 2 (2.6 %), 3 (3.8 %), 2 (2.6 %), and 1 (1.3 %) isolates, respectively. Active efflux pumps, AmpC β-lactamase overproduction, and extended-spectrum AmpC cephalosporinases (ESACs) were found in 58 (74.4 %), 25 (32.1 %) and 15 (19.2 %) of IRPA isolates, respectively. oprD mutations with amino acid substitution, shortened putative loop L7, premature stop codon caused by point mutation, frameshift by nucleotide insertion or deletion, and interruption by insertion sequence were found in 19 (24.4 %), 18 (23.1 %), 15 (19.2 %), 14 (17.9 %), and 10 (12.8 %) of isolates, respectively. This study suggests that alterations in the OprD protein and having an active efflux pump are the main mechanisms associated with bloodstream isolated IRPA. Overproduction of AmpC, ESACs, and the presence of VIM- and OXA-type β-lactamases play additional roles in reduced susceptibility to imipenem in P. aeruginosa isolates in Taiwan.

  15. Evaluation of Mannosidase and Trypsin Enzymes Effects on Biofilm Production of Pseudomonas aeruginosa Isolated from Burn Wound Infections

    PubMed Central

    Banar, Maryam; Emaneini, Mohammad; Satarzadeh, Mhboubeh; Abdellahi, Nafiseh; Beigverdi, Reza; van Leeuwen, Willem B.; Jabalameli, Fereshteh

    2016-01-01

    Biofilm is an important virulence factor in Pseudomonas aeruginosa and has a substantial role in antibiotic resistance and chronic burn wound infections. New therapeutic agents against P. aeruginosa, degrading biofilms in burn wounds and improving the efficacy of current antimicrobial agents, are required. In this study, the effects of α-mannosidase, β-mannosidase and trypsin enzymes on the degradation of P. aeruginosa biofilms and on the reduction of ceftazidime minimum biofilm eliminating concentrations (MBEC) were evaluated. All tested enzymes, destroyed the biofilms and reduced the ceftazidime MBECs. However, only trypsin had no cytotoxic effect on A-431 human epidermoid carcinoma cell lines. In conclusion, since trypsin had better features than mannosidase enzymes, it can be a promising agent in combatting P. aeruginosa burn wound infections. PMID:27736961

  16. Differences between Pseudomonas aeruginosa in a clinical sample and in a colony isolated from it: comparison of virulence capacity and susceptibility of biofilm to inhibitors.

    PubMed

    Ramos, A N; Peral, M C; Valdez, J C

    2010-05-01

    We study the differences between Pseudomonas aeruginosa from an infected wound (clinical strain) and a colony isolated from it. We assessed the in vitro inhibition of these P. aeruginosa biofilms by DNase and filtrate of Lactobacillus plantarum cultures (acid=AF and neutralize=NF) with crystal violet technique. Inhibition by AF was greatest than DNase for clinical and isolated strain (p<0.001) and greatest than NF for clinical (p<0.05) and isolated strain (p<0.001). Using a burn model in mice, we compared the infection producing by clinical and isolated strains in planktonic and biofilm form. Deaths were quantified and the infection was assessed by determining CFU/g of tissue in the lesion, spleen and liver. The infections with planktonic bacteria tended to become systemic and more deadly than biofilm infections. All infected wounds required the same healing period (30 days). These findings were independent of the origin of the bacteria (clinical or colony isolated strain).

  17. Multidrug-Resistant Sequence Type 235 Pseudomonas aeruginosa Clinical Isolates Producing IMP-26 with Increased Carbapenem-Hydrolyzing Activities in Vietnam

    PubMed Central

    Tada, Tatsuya; Nhung, Pham Hong; Miyoshi-Akiyama, Tohru; Shimada, Kayo; Tsuchiya, Mitsuhiro; Phuong, Doan Mai; Anh, Nguyen Quoc; Ohmagari, Norio

    2016-01-01

    Forty clinical isolates of multidrug-resistant Pseudomonas aeruginosa were obtained in a medical setting in Hanoi, Vietnam. Whole genomes of all 40 isolates were sequenced by MiSeq (Illumina), and phylogenic trees were constructed from the single nucleotide polymorphism concatemers. Of these 40 isolates, 24 (60.0%) harbored metallo-β-lactamase-encoding genes, including blaIMP-15, blaIMP-26, blaIMP-51, and/or blaNDM-1. Of these 24 isolates, 12 harbored blaIMP-26 and belonged to sequence type 235 (ST235). Escherichia coli expressing blaIMP-26 was significantly more resistant to doripenem and meropenem than E. coli expressing blaIMP-1 and blaIMP-15. IMP-26 showed higher catalytic activity against doripenem and meropenem than IMP-1 and against all carbapenems tested, including doripenem, imipenem, meropenem, and panipenem, than did IMP-15. These data suggest that clinical isolates of multidrug-resistant ST235 P. aeruginosa producing IMP-26 with increased carbapenem-hydrolyzing activities are spreading in medical settings in Vietnam. PMID:27600046

  18. Multidrug-Resistant Sequence Type 235 Pseudomonas aeruginosa Clinical Isolates Producing IMP-26 with Increased Carbapenem-Hydrolyzing Activities in Vietnam.

    PubMed

    Tada, Tatsuya; Nhung, Pham Hong; Miyoshi-Akiyama, Tohru; Shimada, Kayo; Tsuchiya, Mitsuhiro; Phuong, Doan Mai; Anh, Nguyen Quoc; Ohmagari, Norio; Kirikae, Teruo

    2016-11-01

    Forty clinical isolates of multidrug-resistant Pseudomonas aeruginosa were obtained in a medical setting in Hanoi, Vietnam. Whole genomes of all 40 isolates were sequenced by MiSeq (Illumina), and phylogenic trees were constructed from the single nucleotide polymorphism concatemers. Of these 40 isolates, 24 (60.0%) harbored metallo-β-lactamase-encoding genes, including blaIMP-15, blaIMP-26, blaIMP-51, and/or blaNDM-1 Of these 24 isolates, 12 harbored blaIMP-26 and belonged to sequence type 235 (ST235). Escherichia coli expressing blaIMP-26 was significantly more resistant to doripenem and meropenem than E. coli expressing blaIMP-1 and blaIMP-15 IMP-26 showed higher catalytic activity against doripenem and meropenem than IMP-1 and against all carbapenems tested, including doripenem, imipenem, meropenem, and panipenem, than did IMP-15. These data suggest that clinical isolates of multidrug-resistant ST235 P. aeruginosa producing IMP-26 with increased carbapenem-hydrolyzing activities are spreading in medical settings in Vietnam. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  19. Assessment of the correlation among antibiotic resistance, adherence to abiotic and biotic surfaces, invasion and cytotoxicity of Pseudomonas aeruginosa isolated from diseased gilthead sea bream.

    PubMed

    Lamari, Faouzi; Chakroun, Ibtissem; Rtimi, Sami

    2017-07-01

    Improper uses of antibiotics to treat fish disease pose an increase of multidrug resistance in Pseudomonas aeruginosa. In order to escape host antimicrobial agents and induce cytotoxicity, different virulence properties are needed by these bacteria such as, biofilm formation, adhesion and invasion ability. This study was conducted to isolate Pseudomonas aeruginosa from diseased cultured gilthead sea bream. Seventeen isolates of Pseudomonas aeruginosa were identified by PCR. All of the isolates tested were susceptible to Gentamicin and Ciprofloxacin. Highest level of resistance was observed against Erythromycin, Ampicillin and Tetracycline. Among the 17 isolates, 11 showed multi-drug resistance. The isolates were screened for biofilm formation in abiotic surfaces, adherence, invasion and cytotoxicity against Hep-2 cells. We found that some strains were able to adhere to abiotic and biotic surface and to enter inside Hep-2 cells. Using cytochalasin D inhibitor, we observed a significant decrease in invasion of epithelial cells. The 17 washed bacterial cells induce variable degree of cytotoxicity. However, no cytotoxic effects on Hep-2 cells were obtained among the totality of cell free filtrate of Pseudomonas strains. By studying the relationship between different virulence properties, a significant positive correlation was obtained between both biofilm formation and adherence, and between adherence and invasion to epithelial cells. Subsequently, we found that the mean values of adhesion and invasion in the MDR group were significantly higher than those observed in the non-MDR group. Likewise, a significant positive correlation was found among adhesive and invasive capacities of Pseudomonas strains and their antibiotic resistance phenotypes. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Waste Isolation Pilot Plant 1999 Site Environmental Report

    SciTech Connect

    Evans, Roy B.; Adams, Amy; Martin, Don; Morris, Randall C.; Reynolds, Timothy D.; Warren, Ronald W.

    2000-09-30

    The U.S. Department of Energy's (DOE)Carlsbad Area Office and the Westinghouse Waste Isolation Division (WID) are dedicated to maintaining high quality management of Waste Isolation Pilot Plant (WIPP) environmental resources. DOE Order 5400.1, General Environmental Protection Program, and DOE Order 231.1, Environmental, Safety, and Health Reporting, require that the environment at and near DOE facilities be monitored to ensure the safety and health of the public and the environment. This Waste Isolation Pilot Plant 1999 Site Environmental Report summarizes environmental data from calendar year 1999 that characterize environmental management performance and demonstrate compliance with federal and state regulations. This report was prepared in accordance with DOE Order 5400.1, DOE Order 231.1, the Environmental Regulatory Guide for Radiological Effluent Monitoring and Environmental Surveillance (DOE/EH- 0173T), and the Waste Isolation Pilot Plant Environmental Protection Implementation Plan (DOE/WIPP 96-2199). The above orders and guidance documents require that DOE facilities submit an Annual Site Environmental Report to DOE Headquarters, Office of the Assistant Secretary for Environment, Safety, and Health. The purpose of this report is to provide a comprehensive description of operational environmental monitoring activities, to provide an abstract of environmental activities conducted to characterize site environmental management performance to confirm compliance with environmental standards and requirements, and to highlight significant programs and efforts of environmental merit at WIPP during calendar year 1999. WIPP received its first shipment of waste on March 26, 1999. In 1999, no evidence was found of any adverse effects from WIPP on the surrounding environment. Radionuclide concentrations in the environment surrounding WIPP were not statistically higher in 1999 than in 1998.

  1. Microbial interaction between a CTXM-15 -producing Escherichia coli and a susceptible Pseudomonas aeruginosa isolated from bronchoalveolar lavage: influence of cefotaxime in the dual-species biofilm formation.

    PubMed

    Bessa, Lucinda J; Mendes, Ângelo; Gomes, Rita; Curvelo, Sara; Cravo, Sara; Sousa, Emília; Vasconcelos, Vitor; Martins da Costa, Paulo

    2015-06-01

    Two isolates, Escherichia coli ella00 and Pseudomonas aeruginosa ella01, obtained from bronchoalveolar lavage, were found to be closely associated in clusters in agar medium. Escherichia coli ella00 was multidrug resistant and CTXM-15 extended-spectrum β-lactamase producer, while P. aeruginosa ella01 was susceptible to all antimicrobials tested. These observations impelled for further studies aimed to understand their microbial interaction. The P. aeruginosa ella01 biofilm-forming capacity was reduced and not affected when it was co-cultured with E. coli ella00 and E. coli ATCC 25922 respectively. Interestingly, the co-culture of ella isolates in the presence of high concentrations, such as 160 μg ml(-1) , of cefotaxime allowed the formation of more biofilm than in the absence of the antibiotic. As revealed by fluorescence in situ hybridization, in co-culture, P. aeruginosa ella01 survived and subsequently flourished when exposed to this third-generation cephalosporin at a concentration 10 × higher than its minimum inhibitory concentration (MIC), and this was mostly due to β-lactamases production by E. coli ella00. In fact, it was demonstrated by high-performance liquid chromatography that cefotaxime was absent for the culture medium 4 h after application. In conclusion, we demonstrate that bacterial species can interact differently depending on the surrounding conditions (favourable or stressing), and that those interactions can switch from unprofitable to beneficial. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  2. Waste Isolation Pilot Plant CY 2000 Site Environmental Report

    SciTech Connect

    Westinghouse TRU Solutions, LLC; Environmental Science and Research Foundation, Inc.

    2001-12-31

    The U.S. Department of Energy's (DOE) Carlsbad Field Office and Westinghouse TRU Solutions, LLC (WTS) are dedicated to maintaining high quality management of Waste Isolation Pilot Plant (WIPP) environmental resources. DOE Order 5400.1, General Environmental Protection Program, and DOE Order 231.1, Environmental, Safety, and Health Reporting, require that the environment at and near DOE facilities be monitored to ensure the safety and health of the public and the environment. This Waste Isolation Pilot Plant 2000 Site Environmental Report summarizes environmental data from calendar year (CY) 2000 that characterize environmental management performance and demonstrate compliance with federal and state regulations. This report was prepared in accordance with DOE Order 5400.1, DOE Order 231.1, the Environmental Regulatory Guide for Radiological Effluent Monitoring and Environmental Surveillance (DOE/EH-0173T), and the Waste Isolation Pilot Plant Environmental Protect ion Implementation Plan (DOE/WIPP 96-2199). The above orders and guidance documents require that DOE facilities submit an Annual Site Environmental Report to DOE Headquarters, Office of the Assistant Secretary for Environment, Safety, and Health. The purpose of this report is to provide a comprehensive description of operational environmental monitoring activities, to provide an abstract of environmental activities conducted to characterize site environmental management performance to confirm compliance with environmental standards and requirements, and to highlight significant programs and efforts of environmental merit at WIPP during CY 2000. The format of this report follows guidance offered in a June 1, 2001 memo from DOE's Office of Policy and Guidance with the subject ''Guidance for the preparation of Department of Energy (DOE) Annual Site Environmental Reports (ASERs) for Calendar Year 2000.'' WIPP received its first shipment of waste on March 26, 1999. In 2000, no evidence was found of any adverse

  3. Antimicrobial Activity of Fosfomycin-Tobramycin Combination against Pseudomonas aeruginosa Isolates Assessed by Time-Kill Assays and Mutant Prevention Concentrations

    PubMed Central

    Díez-Aguilar, María; Tedim, Ana P.; Rodríguez, Irene; Aktaş, Zerrin; Cantón, Rafael

    2015-01-01

    The antibacterial activity of fosfomycin-tobramycin combination was studied by time-kill assay in eight Pseudomonas aeruginosa clinical isolates belonging to the fosfomycin wild-type population (MIC = 64 μg/ml) but with different tobramycin susceptibilities (MIC range, 1 to 64 μg/ml). The mutant prevention concentration (MPC) and mutant selection window (MSW) were determined in five of these strains (tobramycin MIC range, 1 to 64 μg/ml) in aerobic and anaerobic conditions simulating environments that are present in biofilm-mediated infections. Fosfomycin-tobramycin was synergistic and bactericidal for the isolates with mutations in the mexZ repressor gene, with a tobramycin MIC of 4 μg/ml. This effect was not observed in strains displaying tobramycin MICs of 1 to 2 μg/ml due to the strong bactericidal effect of tobramycin alone. Fosfomycin presented higher MPC values (range, 2,048 to >2,048 μg/ml) in aerobic and anaerobic conditions than did tobramycin (range, 16 to 256 μg/ml). Interestingly, the association rendered narrow or even null MSWs in the two conditions. However, for isolates with high-level tobramycin resistance that harbored aminoglycoside nucleotidyltransferases, time-kill assays showed no synergy, with wide MSWs in the two environments. glpT gene mutations responsible for fosfomycin resistance in P. aeruginosa were determined in fosfomycin-susceptible wild-type strains and mutant derivatives recovered from MPC studies. All mutant derivatives had changes in the GlpT amino acid sequence, which resulted in a truncated permease responsible for fosfomycin resistance. These results suggest that fosfomycin-tobramycin can be an alternative for infections due to P. aeruginosa since it has demonstrated synergistic and bactericidal activity in susceptible isolates and those with low-level tobramycin resistance. It also prevents the emergence of resistant mutants in either aerobic or anaerobic environments. PMID:26195514

  4. Antimicrobial Activity of Fosfomycin-Tobramycin Combination against Pseudomonas aeruginosa Isolates Assessed by Time-Kill Assays and Mutant Prevention Concentrations.

    PubMed

    Díez-Aguilar, María; Morosini, María Isabel; Tedim, Ana P; Rodríguez, Irene; Aktaş, Zerrin; Cantón, Rafael

    2015-10-01

    The antibacterial activity of fosfomycin-tobramycin combination was studied by time-kill assay in eight Pseudomonas aeruginosa clinical isolates belonging to the fosfomycin wild-type population (MIC = 64 μg/ml) but with different tobramycin susceptibilities (MIC range, 1 to 64 μg/ml). The mutant prevention concentration (MPC) and mutant selection window (MSW) were determined in five of these strains (tobramycin MIC range, 1 to 64 μg/ml) in aerobic and anaerobic conditions simulating environments that are present in biofilm-mediated infections. Fosfomycin-tobramycin was synergistic and bactericidal for the isolates with mutations in the mexZ repressor gene, with a tobramycin MIC of 4 μg/ml. This effect was not observed in strains displaying tobramycin MICs of 1 to 2 μg/ml due to the strong bactericidal effect of tobramycin alone. Fosfomycin presented higher MPC values (range, 2,048 to >2,048 μg/ml) in aerobic and anaerobic conditions than did tobramycin (range, 16 to 256 μg/ml). Interestingly, the association rendered narrow or even null MSWs in the two conditions. However, for isolates with high-level tobramycin resistance that harbored aminoglycoside nucleotidyltransferases, time-kill assays showed no synergy, with wide MSWs in the two environments. glpT gene mutations responsible for fosfomycin resistance in P. aeruginosa were determined in fosfomycin-susceptible wild-type strains and mutant derivatives recovered from MPC studies. All mutant derivatives had changes in the GlpT amino acid sequence, which resulted in a truncated permease responsible for fosfomycin resistance. These results suggest that fosfomycin-tobramycin can be an alternative for infections due to P. aeruginosa since it has demonstrated synergistic and bactericidal activity in susceptible isolates and those with low-level tobramycin resistance. It also prevents the emergence of resistant mutants in either aerobic or anaerobic environments.

  5. Stable antimicrobial susceptibility rates for clinical isolates of Pseudomonas aeruginosa from the 2001-2003 tracking resistance in the United States today surveillance studies.

    PubMed

    Karlowsky, James A; Jones, Mark E; Thornsberry, Clyde; Evangelista, Alan T; Yee, Y Cheung; Sahm, Daniel F

    2005-02-15

    From 2001 to 2003, rates of susceptibility to piperacillin-tazobactam (86%), ceftazidime (80%), ciprofloxacin (68%), and levofloxacin (67%) did not decrease or decreased by <1.5%, whereas the rate of susceptibility to gentamicin decreased by 3.2% (from 75.5% to 72.3%) and the rate of susceptibility to imipenem decreased by 5.6% (from 84.4% to 78.8%), for 2394 clinical isolates of Pseudomonas aeruginosa collected in the Tracking Resistance in the United States Today surveillance studies. Rates of multidrug resistance (i.e., resistance to > or =3 antimicrobial agents) increased from 7.2% in 2001 to 9.9% in 2003 and were significantly higher for isolates from the East North Central and Mid-Atlantic regions of the United States than for isolates from other regions. Analysis of minimum inhibitory concentrations (MICs) suggested that combining an antipseudomonal beta -lactam with ciprofloxacin or levofloxacin would yield a 3.4%-7.1% increase in the percentage of isolates susceptible to the combination, compared with the beta -lactam alone. Ratios of the area under the serum concentration-time curve values for free drug to modal MICs for ciprofloxacin and levofloxacin were similar and were >125 (target ratio), whereas those ratios for gatifloxacin and moxifloxacin were significantly lower. Ongoing surveillance of P. aeruginosa is essential.

  6. Correlation between cytotoxicity induced by Pseudomonas aeruginosa clinical isolates from acute infections and IL-1β secretion in a model of human THP-1 monocytes.

    PubMed

    Anantharajah, Ahalieyah; Buyck, Julien M; Faure, Emmanuel; Glupczynski, Youri; Rodriguez-Villalobos, Hector; De Vos, Daniel; Pirnay, Jean-Paul; Bilocq, Florence; Guery, Benoît; Tulkens, Paul M; Mingeot-Leclercq, Marie-Paule; Van Bambeke, Françoise

    2015-10-01

    Type III secretion system (T3SS) in Pseudomonas aeruginosa is associated with poor clinical outcome in acute infections. T3SS allows for injection of bacterial exotoxins (e.g. ExoU or ExoS) into the host cell, causing cytotoxicity. It also activates the cytosolic NLRC4 inflammasome, activating caspase-1, inducing cytotoxicity and release of mature IL-1β, which impairs bacterial clearance. In addition, flagellum-mediated motility has been suggested to also modulate inflammasome response and IL-1β release. Yet the capacity of clinical isolates to induce IL-1β release and its relation with cytotoxicity have never been investigated. Using 20 clinical isolates from acute infections with variable T3SS expression levels and human monocytes, our aim was to correlate IL-1β release with toxin expression, flagellar motility and cytotoxicity. ExoU-producing isolates caused massive cell death but minimal release of IL-1β, while those expressing T3SS but not ExoU (i.e. expressing ExoS or no toxins) induced caspase-1 activation and IL-1β release, the level of which was correlated with cytotoxicity. Both effects were prevented by a specific caspase-1 inhibitor. Flagellar motility was not correlated with cytotoxicity or IL-1β release. No apoptosis was detected. Thus, T3SS cytotoxicity is accompanied by a modification in cytokine balance for P. aeruginosa clinical isolates that do not express ExoU.

  7. Seeking the source of Pseudomonas aeruginosa infections in a recently opened hospital: an observational study using whole-genome sequencing

    PubMed Central

    Quick, Joshua; Cumley, Nicola; Wearn, Christopher M; Niebel, Marc; Constantinidou, Chrystala; Thomas, Chris M; Pallen, Mark J; Moiemen, Naiem S; Bamford, Amy; Oppenheim, Beryl; Loman, Nicholas J

    2014-01-01

    Objectives Pseudomonas aeruginosa is a common nosocomial pathogen responsible for significant morbidity and mortality internationally. Patients may become colonised or infected with P. aeruginosa after exposure to contaminated sources within the hospital environment. The aim of this study was to determine whether whole-genome sequencing (WGS) can be used to determine the source in a cohort of burns patients at high risk of P. aeruginosa acquisition. Study design An observational prospective cohort study. Setting Burns care ward and critical care ward in the UK. Participants Patients with >7% total burns by surface area were recruited into the study. Methods All patients were screened for P. aeruginosa on admission and samples taken from their immediate environment, including water. Screening patients who subsequently developed a positive P. aeruginosa microbiology result were subject to enhanced environmental surveillance. All isolates of P. aeruginosa were genome sequenced. Sequence analysis looked at similarity and relatedness between isolates. Results WGS for 141 P. aeruginosa isolates were obtained from patients, hospital water and the ward environment. Phylogenetic analysis revealed eight distinct clades, with a single clade representing the majority of environmental isolates in the burns unit. Isolates from three patients had identical genotypes compared with water isolates from the same room. There was clear clustering of water isolates by room and outlet, allowing the source of acquisitions to be unambiguously identified. Whole-genome shotgun sequencing of biofilm DNA extracted from a thermostatic mixer valve revealed this was the source of a P. aeruginosa subpopulation previously detected in water. In the remaining two cases there was no clear link to the hospital environment. Conclusions This study reveals that WGS can be used for source tracking of P. aeruginosa in a hospital setting, and that acquisitions can be traced to a specific source within a

  8. Waste Isolation Pilot Plant 2001 Site Environmental Report

    SciTech Connect

    Westinghouse TRU Solutions, Inc.

    2002-09-20

    The United States (U.S.) Department of Energy's (DOE) Carlsbad Field Office (CBFO) and Westinghouse TRU Solutions LLC (WTS) are dedicated to maintaining high quality management of Waste Isolation Pilot Plant (WIPP) environmental resources. DOE Order 5400.1, General Environmental Protection Program, and DOE Order 231.1, Environmental, Safety, and Health Reporting, require that the environment at and near DOE facilities be monitored to ensure the safety and health of the public and the environment. This Waste Isolation Pilot Plant 2001 Site Environmental Report summarizes environmental data from calendar year (CY) 2001 that characterize environmental management performance and demonstrate compliance with federal and state regulations. This report was prepared in accordance with DOE Order 5400.1, DOE Order 231.1, the Environmental Regulatory Guide for Radiological Effluent Monitoring and Environmental Surveillance (DOE/EH- 0173T), and the Waste Isolation Pilot Plant Environmental Protection Implementation Plan (DOE/WIPP 96-2199). The above Orders and guidance documents require that DOE facilities submit an annual site environmental report to DOE Headquarters, Office of the Assistant Secretary for Environment, Safety, and Health; and the New Mexico Environment Department (NMED). The purpose of this report is to provide a comprehensive description of operational environmental monitoring activities, to provide an abstract of environmental activities conducted to characterize site environmental management performance to confirm compliance with environmental standards and requirements, and to highlight significant programs and efforts of environmental merit at WIPP during CY 2001. WIPP received its first shipment of waste on March 26, 1999. In 2001, no evidence was found of any adverse effects from WIPP on the surrounding environment.

  9. Molecular detection of metallo-β-lactamase genes, bla IMP-1, bla VIM-2 and bla SPM-1 in imipenem resistant Pseudomonas aeruginosa isolated from clinical specimens in teaching hospitals of Ahvaz, Iran.

    PubMed

    Moosavian, Mojtaba; Rahimzadeh, Mohammad

    2015-02-01

    Carbapenem resistant Pseudomonas aeruginosa is a serious cause of nosocomial infections. The main purpose of the study is to determine the prevalence rate of imipenem resistant Pseudomonas aeruginosa carrying metallo-ß-lactamase (MBL) genes. 236 Pseudomonas aeruginosa isolates were collected from teaching hospitals of Ahvaz University of Medical Sciences during a period of 9 months in 2012. These strains were identified using conventional microbiological tests. The susceptibility of isolates to antibiotics were assessed using disk diffusion test. The IMP-EDTA combination disk phenotypic test was performed for detection of MBL producing strains. Finally, polymerase chain reaction (PCR) was performed to detect MBL genes, bla IMP-1, bla VIM-2 and bla SPM-1 in imipenem resistant strains. Out of 236 examined isolates, 122 isolates (51.4%) were resistant to imipenem. The IMP-EDTA combination test showed that among 122 imipenem resistant strains, 110 strains (90%) were phenotipically MBL producers. Additionally, the results of PCR method showed that 2 strains (1.6%) and 67strains (55%) of imipenem resistant Pseudomonas aeruginosa isolates contained bla VIM-2 and bla IMP-1 genes respectively. No SPM-1gene was found in the examined samples. Resistance of P. aeruginosa isolates to imipenem due to MBL enzymes is increasing in Ahavaz. Because of clinical significance of this kind of resistance, rapid detection of MBL producing strains and followed by appropriate treatment is necessary to prevent the spreading of these organisms.

  10. [Investigation of the frequency of PER-1 type beta-lactamase and antimicrobial resistance rates in nosocomial isolates of Pseudomonas aeruginosa].

    PubMed

    Atilla, Aynur; Eroğlu, Cafer; Esen, Saban; Sünbül, Mustafa; Leblebicioğlu, Hakan

    2012-01-01

    Pseudomonas aeruginosa which is a common cause of nosocomial infections, usually leads to treatment difficulties due to multi-drug resistance. PER-1 type extended-spectrum beta-lactamase (ESBL) producing bacteria are shown to be common in Turkey. Since limited number of antibiotics such as antipseudomonal penicillins, cephalosporins, aminoglycosides, fluoroquinolones and carbapenems are available for the treatment of P.aeruginosa infections, it is essential to monitor and eventually control the spread of antibiotic resistance genes. The aims of this study were to investigate the presence of PER-1 type ESBLs in nosocomial P.aeruginosa isolates and to evaluate their resistance to some commonly used antibiotics. A total of 110 P.aeruginosa strains isolated from clinical samples [40 urine, 26 exudate, 20 blood, 24 others (sputum, tracheal aspirate, tissue biopsy, cerebrospinal fluid, pleural fluid, conjunctiva)] of the inpatients who were proven to have nosocomial infections in Ondokuz Mayıs University Faculty of Medicine Hospital between May 2002-June 2003 were included in the study. Identification of the isolates was performed by ATB system ID 32 GN (bio-Merieux, France). Antibiotic susceptibilities were detected by standard disk diffusion method and PER-1 type ESBL was searched by polymerase chain reaction using PER-1 and PER- 2 primers. PER-1 positivity was detected in 62 of 110 (56.4%) P.aeruginosa isolates and 51 of 65 (78.5%) ceftazidime-resistant strains. The highest susceptibility rate was detected for ciprofloxacin (76.4%), while the lowest susceptibility rate was for ticarcillin-clavulanic acid (22.7%). Rates of resistance to beta-lactam agents (excluding piperacillin/tazobactam), amikacin and gentamicin were statistically significantly higher for PER-1 positive strains than PER-1 negative ones. Resistance rates to ceftazidime, cefepime, aztreonam, piperacillin and ticarcillin-clavulanic acid in PER-1 positive isolates versus negative ones were as 82.3% vs

  11. Dynamics of toxic genotypes of Microcystis aeruginosa complex (MAC) through a wide freshwater to marine environmental gradient.

    PubMed

    Martínez de la Escalera, Gabriela; Kruk, Carla; Segura, Angel M; Nogueira, Lucía; Alcántara, Ignacio; Piccini, Claudia

    2017-02-01

    Bloom-forming species belonging to Microcystis aeruginosa complex (MAC) are the most commonly reported worldwide. MAC blooms are composed by toxic and non-toxic genotypes and the environmental conditions favouring the dominance of toxic genotypes are still a matter of debate among the scientific community. In this study, we evaluated the distribution of toxic MAC genotypes along a seasonal cycle and over an environmental gradient spanning 800km, from a eutrophic freshwater reservoir in Río Uruguay to marine water in the outer limit of Río de la Plata. Abundance of four mcy genes, mcyB, mcyD, mcyE and mcyJ was determined by qPCR and used as a proxy of abundance of toxic MAC genotypes. All the mcy genes were detected through the seasonal cycle at all sampling sites, being systematically higher in the freshwater reservoir and decreasing towards the marine site. The highest toxic genotype abundance was found during the austral summer months. According to generalized linear regressions and random forest models, temperature and conductivity were the most relevant explanatory variables. This suggests that although toxic MAC genotypes grow optimally in freshwater, they are also able to tolerate the high-salinity and low temperature conditions found in estuarine and marine waters. This ability to resist harsh conditions impose a health risk and a management challenge. To our knowledge, this is the first report addressing several mcy genes in a broad gradient that includes a wide array of different environmental conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Novel Combinations of Synthesized ZnO NPs and Ceftazidime: Evaluation of their Activity against Standards and New Clinically Isolated Pseudomonas aeruginosa

    PubMed Central

    Isaei, Elham; Mansouri, Shahla; Mohammadi, Fereshteh; Taheritarigh, Sadegh; Mohammadi, Zohreh

    2016-01-01

    Background: Antibiotic resistant bacteria can be considered as a main problem in infection management. Zinc oxide nanoparticles (ZnO NPs), individually or in combination with antibiotics, can be considered as good candidates for struggling against drug resistant bacteria. Methods: In this study, Zinc oxide nanoparticles were synthesized using sol-gel method in low temperature as a cost effective procedure and characterized by X-ray diffraction and Scanning Electron Microscopy. Antibacterial activity of 9 new combinations of Zinc oxide nanoparticles and ceftazidime was assessed against standards and new clinically isolated multi drug resistant Pseudomonas aeruginosa (P. aeruginosa), in order to evaluate enhancement effect of synthesized Zinc oxide nanoparticles on antibacterial activity of ceftazidime. Results: The results indicated that desirable effects can be seen at 6 and 7 mM of Zinc oxide nanoparticles (60 to 100% inhibition). Moreover, after evaluation of 9 new combinations with various concentrations of both components, it was demonstrated that Zinc oxide nanoparticles can enhance the antibacterial activity of ceftazidime, against some bacterial strains of P. aeruginosa. The highest activity was observed with the concentration of 20 μg/ml ceftazidime in the presence of 5, 6 or 7 mM of Zinc oxide nanoparticles. Conclusion: Zinc oxide nanoparticles in appropriate concentrations can be proposed as new and promising candidates for overcoming bacterial resistance. PMID:27920884

  13. Ability of the VITEK 2 Advanced Expert System To Identify β-Lactam Phenotypes in Isolates of Enterobacteriaceae and Pseudomonas aeruginosa

    PubMed Central

    Sanders, Christine C.; Peyret, Michel; Moland, Ellen Smith; Shubert, Carole; Thomson, Kenneth S.; Boeufgras, Jean-Marc; Sanders, W. Eugene

    2000-01-01

    The Advanced Expert System (AES) was used in conjunction with the VITEK 2 automated antimicrobial susceptibility test system to ascertain the β-lactam phenotypes of 196 isolates of the family Enterobacteriaceae and the species Pseudomonas aeruginosa. These isolates represented a panel of strains that had been collected from laboratories worldwide and whose β-lactam phenotypes had been characterized by biochemical and molecular techniques. The antimicrobial susceptibility of each isolate was determined with the VITEK 2 instrument, and the results were analyzed with the AES to ascertain the β-lactam phenotype. The results were then compared to the β-lactam resistance mechanism determined by biochemical and molecular techniques. Overall, the AES was able to ascertain a β-lactam phenotype for 183 of the 196 (93.4%) isolates tested. For 111 of these 183 (60.7%) isolates, the correct β-lactam phenotype was identified definitively in a single choice by the AES, while for an additional 46 isolates (25.1%), the AES identified the correct β-lactam phenotype provisionally within two or more choices. For the remaining 26 isolates (14.2%), the β-lactam phenotype identified by the AES was incorrect. However, for a number of these isolates, the error was due to remediable problems. These results suggest that the AES is capable of accurate identification of the β-lactam phenotypes of gram-negative isolates and that certain modifications can improve its performance even further. PMID:10655347

  14. CpxR Activates MexAB-OprM Efflux Pump Expression and Enhances Antibiotic Resistance in Both Laboratory and Clinical nalB-Type Isolates of Pseudomonas aeruginosa

    PubMed Central

    Yi, Xue-Xian; O’Gara, Fergal; Wang, Yi-Ping

    2016-01-01

    Resistance-Nodulation-Division (RND) efflux pumps are responsible for multidrug resistance in Pseudomonas aeruginosa. In this study, we demonstrate that CpxR, previously identified as a regulator of the cell envelope stress response in Escherichia coli, is directly involved in activation of expression of RND efflux pump MexAB-OprM in P. aeruginosa. A conserved CpxR binding site was identified upstream of the mexA promoter in all genome-sequenced P. aeruginosa strains. CpxR is required to enhance mexAB-oprM expression and drug resistance, in the absence of repressor MexR, in P. aeruginosa strains PA14. As defective mexR is a genetic trait associated with the clinical emergence of nalB-type multidrug resistance in P. aeruginosa during antibiotic treatment, we investigated the involvement of CpxR in regulating multidrug resistance among resistant isolates generated in the laboratory via antibiotic treatment and collected in clinical settings. CpxR is required to activate expression of mexAB-oprM and enhances drug resistance, in the absence or presence of MexR, in ofloxacin-cefsulodin-resistant isolates generated in the laboratory. Furthermore, CpxR was also important in the mexR-defective clinical isolates. The newly identified regulatory linkage between CpxR and the MexAB-OprM efflux pump highlights the presence of a complex regulatory network modulating multidrug resistance in P. aeruginosa. PMID:27736975

  15. Effects of mucoid and non-mucoid Pseudomonas aeruginosa isolates from cystic fibrosis patients on inflammatory mediator release from human polymorphonuclear granulocytes and rat mast cells.

    PubMed Central

    Friedl, P; König, B; König, W

    1992-01-01

    Mucoid Pseudomonas aeruginosa causing chronic bronchopulmonary infection in cystic fibrosis (CF) patients may interfere with host defence mechanisms. We investigated 13 P. aeruginosa strains isolated from sputa of CF patients with regard to the induction or modulation of inflammatory mediator release from human neutrophils (PMN) and rat mast cells. The effects of mucoid as compared to non-mucoid bacteria were studied using a mucoid strain and its non-mucoid revertant. The release of leukotrienes (LT) and histamine in response to the majority of the CF strains was insignificant. However, preincubation of PMN with P. aeruginosa caused a dose-dependent decrease (50-95%) of LTB4 and LTC4 generation and LTB4 metabolism induced by the Ca(2+)-ionophore A23187 or opsonized zymosan (ZX) (P less than 0.001). The mucoid strains caused a three- to 10-fold higher impairment of LTB4 release (P less than 0.05) and a concomitant down-regulation of LTB4 receptors on neutrophils. Inhibitory effects were also obtained for mucoid and non-mucoid bacteria when the phorbol-ester or the Ca(2+)-ionophore induced luminol enhanced chemiluminescence response (P less than 0.001) or the histamine release from rat peritoneal mast cells (P less than 0.01) was studied. The bacteria-cell contact with non-mucoid strains was associated with an increased Ca2+ influx into PMN, whereas mucoid bacteria had no effect. In addition, a protein kinase C-dependent decrease of the C3bi receptor was suppressed by the mucoid--and less effectively--by the non-mucoid strain. The results suggest that the impairment of the phagocytic and inflammatory system may contribute to the pathogenesis and persistence of mucoid P. aeruginosa infection in CF. PMID:1321094

  16. Molecular Epidemiology of a Pseudomonas aeruginosa Hospital Outbreak Driven by a Contaminated Disinfectant-Soap Dispenser

    PubMed Central

    Lanini, Simone; D'Arezzo, Silvia; Puro, Vincenzo; Martini, Lorena; Imperi, Francesco; Piselli, Pierluca; Montanaro, Marco; Paoletti, Simonetta; Visca, Paolo; Ippolito, Giuseppe

    2011-01-01

    Background and Objective Pseudomonas aeruginosa infection represents a main cause of morbidity and mortality among immunocompromised patients. This study describes a fatal epidemic of P. aeruginosa that occurred in a hematology unit in Italy. Methods Retrospective cohort study, prospective surveillance, auditing, extensive testing on healthcare workers and environmental investigation were performed to define the dynamics and potential causes of transmission. RAPD, macrorestriction analyses and sequence typing were used to define relationships between P. aeruginosa isolates. Results Eighteen cases of infection were identified in the different phases of the investigation. Of these, five constitute a significant molecular cluster of infection. A P. aeruginosa strain with the same genetic fingerprint and sequence type (ST175) as clinical isolates strain was also isolated from a heavily contaminated triclosan soap dispenser. Discussion and Conclusions Our results are consistent with the hypothesis that patients became indirectly infected, e.g., during central venous catheter handling through contaminated items, and that the triclosan soap dispenser acted as a common continuous source of P. aeruginosa infection. Since P. aeruginosa is intrinsically unsusceptible to triclosan, the use of triclosan-based disinfectant formulations should be avoided in those healthcare settings hosting patients at high risk of P. aeruginosa infection. PMID:21359222

  17. Emergence of a mutL Mutation Causing Multilocus Sequence Typing–Pulsed-Field Gel Electrophoresis Discrepancy among Pseudomonas aeruginosa Isolates from a Cystic Fibrosis Patient

    PubMed Central

    García-Castillo, María; Máiz, Luis; Morosini, María-Isabel; Rodríguez-Baños, Mercedes; Suarez, Lucrecia; Fernández-Olmos, Ana; Baquero, Fernando; Cantón, Rafael

    2012-01-01

    A multilocus sequence type (MLST) shift (from ST242 to ST996) was detected in Pseudomonas aeruginosa isolates with a uniform pulsed-field gel electrophoresis (PFGE) pattern obtained from a chronically colonized patient. MLST mutational change involved the mutL gene with the consequent emergence of a hypermutable phenotype. This observation challenges the required neutrality of mutL as an appropriate marker in MLST and alerts researchers to the limitations of MLST-only-based population studies in chronic infections under constant antibiotic selective pressure. PMID:22322352

  18. Emergence of a mutL mutation causing multilocus sequence typing-pulsed-field gel electrophoresis discrepancy among Pseudomonas aeruginosa isolates from a cystic fibrosis patient.

    PubMed

    García-Castillo, María; Máiz, Luis; Morosini, María-Isabel; Rodríguez-Baños, Mercedes; Suarez, Lucrecia; Fernández-Olmos, Ana; Baquero, Fernando; Cantón, Rafael; del Campo, Rosa

    2012-05-01

    A multilocus sequence type (MLST) shift (from ST242 to ST996) was detected in Pseudomonas aeruginosa isolates with a uniform pulsed-field gel electrophoresis (PFGE) pattern obtained from a chronically colonized patient. MLST mutational change involved the mutL gene with the consequent emergence of a hypermutable phenotype. This observation challenges the required neutrality of mutL as an appropriate marker in MLST and alerts researchers to the limitations of MLST-only-based population studies in chronic infections under constant antibiotic selective pressure.

  19. Overexpression of AmpC and Efflux Pumps in Pseudomonas aeruginosa Isolates from Bloodstream Infections: Prevalence and Impact on Resistance in a Spanish Multicenter Study▿

    PubMed Central

    Cabot, Gabriel; Ocampo-Sosa, Alain A.; Tubau, Fe; Macia, María D.; Rodríguez, Cristina; Moya, Bartolomé; Zamorano, Laura; Suárez, Cristina; Peña, Carmen; Martínez-Martínez, Luis; Oliver, Antonio

    2011-01-01

    The prevalence and impact of the overexpression of AmpC and efflux pumps were evaluated with a collection of 190 Pseudomonas aeruginosa isolates recovered from bloodstream infections in a 2008 multicenter study (10 hospitals) in Spain. The MICs of a panel of 13 antipseudomonal agents were determined by microdilution, and the expressions of ampC, mexB, mexY, mexD, and mexF were determined by real-time reverse transcription (RT)-PCR. Up to 39% of the isolates overexpressed at least one of the mechanisms. ampC overexpression (24.2%) was the most prevalent mechanism, followed by mexY (13.2%), mexB (12.6%), mexF (4.2%), and mexD (2.2%). The overexpression of mexB plus mexY, documented for 5.3% of the isolates, was the only combination showing a significantly (P = 0.02) higher prevalence than expected from the frequencies of the individual mechanisms (1.6%). Additionally, all imipenem-resistant isolates studied (25 representative isolates) showed inactivating mutations in oprD. Most of the isolates nonsusceptible to piperacillin-tazobactam (96%) and ceftazidime (84%) overexpressed ampC, while mexB (25%) and mexY (29%) overexpressions gained relevance among cefepime-nonsusceptible isolates. Nevertheless, the prevalence of mexY overexpression was highest among tobramycin-nonsusceptible isolates (37%), and that of mexB was highest among meropenem-nonsusceptible isolates (33%). Regarding ciprofloxacin-resistant isolates, besides the expected increased prevalence of efflux pump overexpression, a highly significant link to ampC overexpression was documented for the first time: up to 52% of ciprofloxacin-nonsusceptible isolates overexpressed ampC, sharply contrasting with the 24% documented for the complete collection (P < 0.001). In summary, mutation-driven resistance was frequent in P. aeruginosa isolates from bloodstream infections, whereas metallo-β-lactamases, detected in 2 isolates (1%) producing VIM-2, although with increasing prevalences, were still uncommon. PMID

  20. Nosocomial Spread of Colistin-Only-Sensitive Sequence Type 235 Pseudomonas aeruginosa Isolates Producing the Extended-Spectrum β-Lactamases GES-1 and GES-5 in Spain▿

    PubMed Central

    Viedma, Esther; Juan, Carlos; Acosta, Joshi; Zamorano, Laura; Otero, Joaquín R.; Sanz, Francisca; Chaves, Fernando; Oliver, Antonio

    2009-01-01

    The mechanisms responsible for the increasing prevalence of colistin-only-sensitive (COS) Pseudomonas aeruginosa isolates in a Spanish hospital were investigated. Pulsed-field gel electrophoresis revealed that 24 (50%) of the studied isolates belonged to the same clone, identified as the internationally spread sequence type 235 (ST235) through multilocus sequence typing. In addition to several mutational resistance mechanisms, an integron containing seven resistance determinants was detected. Remarkably, the extended-spectrum β-lactamase GES-1 and its Gly170Ser carbapenem-hydrolyzing derivative GES-5 were first documented to be encoded in a single integron. This work is the first to describe GES enzymes in Spain and adds them to the growing list of β-lactamases of concern (PER, VIM, and OXA) detected in ST235 clone isolates. PMID:19738007

  1. Mechanisms of carbapenem resistance in endemic Pseudomonas aeruginosa isolates after an SPM-1 metallo-β-lactamase producing strain subsided in an intensive care unit of a teaching hospital in Brazil

    PubMed Central

    Cacci, Luciana Camila; Chuster, Stephanie Gomes; Martins, Natacha; do Carmo, Pâmella Rodrigues; Girão, Valéria Brígido de Carvalho; Nouér, Simone Aranha; de Freitas, Wania Vasconcelos; de Matos, Juliana Arruda; Magalhães, Ana Cristina de Gouveia; Ferreira, Adriana Lúcia Pires; Picão, Renata Cristina; Moreira, Beatriz Meurer

    2016-01-01

    Carbapenem-resistance mechanisms are a challenge in the treatment of Pseudomonas aeruginosa infections. We investigated changes in P. aeruginosa carbapenem-resistance determinants over a time period of eight years after the emergence of São Paulo metallo-β-lactamase in a university hospital in Rio de Janeiro, Brazil. Patients admitted to the intensive care unit (ICU) were screened for P. aeruginosa colonisation and followed for the occurrence of infections from April 2007 to April 2008. The ICU environment was also sampled. Isolates were typed using random amplified polymorphic DNA, pulsed-field gel electrophoresis and multilocus sequence typing. Antimicrobial susceptibility was determined by disk diffusion and E-test, production of carbapenemases by a modified-CarbaNP test and presence of carbapenemase-encoding genes by polymerase chain reaction. Non-carbapenemase resistance mechanisms studied included efflux and AmpC overexpression by PAβN and cloxacillin susceptibility enhancement, respectively, as well as oprD mutations. From 472 P. aeruginosa clinical isolates (93 patients) and 17 isolates from the ICU environment, high genotypic diversity and several international clones were observed; one environment isolate belonged to the blaSPM-1 P. aeruginosa epidemic genotype. Among isolates from infections, 10 (29%) were carbapenem resistant: none produced carbapenemases, three exhibited all non-carbapenemase mechanisms studied, six presented a combination of two mechanisms, and one exclusively displayed oprD mutations. Carbapenem-resistant P. aeruginosa displayed a polyclonal profile after the SPM-1 epidemic genotype declined. This phenomenon is connected with blaSPM-1 P. aeruginosa replaced by other carbapenem-resistant pathogens. PMID:27653359

  2. Mechanisms of carbapenem resistance in endemic Pseudomonas aeruginosa isolates after an SPM-1 metallo-β-lactamase producing strain subsided in an intensive care unit of a teaching hospital in Brazil.

    PubMed

    Cacci, Luciana Camila; Chuster, Stephanie Gomes; Martins, Natacha; Carmo, Pâmella Rodrigues do; Girão, Valéria Brígido de Carvalho; Nouér, Simone Aranha; Freitas, Wania Vasconcelos de; Matos, Juliana Arruda de; Magalhães, Ana Cristina de Gouveia; Ferreira, Adriana Lúcia Pires; Picão, Renata Cristina; Moreira, Beatriz Meurer

    2016-09-01

    Carbapenem-resistance mechanisms are a challenge in the treatment of Pseudomonas aeruginosa infections. We investigated changes in P. aeruginosa carbapenem-resistance determinants over a time period of eight years after the emergence of São Paulo metallo-β-lactamase in a university hospital in Rio de Janeiro, Brazil. Patients admitted to the intensive care unit (ICU) were screened for P. aeruginosa colonisation and followed for the occurrence of infections from April 2007 to April 2008. The ICU environment was also sampled. Isolates were typed using random amplified polymorphic DNA, pulsed-field gel electrophoresis and multilocus sequence typing. Antimicrobial susceptibility was determined by disk diffusion and E-test, production of carbapenemases by a modified-CarbaNP test and presence of carbapenemase-encoding genes by polymerase chain reaction. Non-carbapenemase resistance mechanisms studied included efflux and AmpC overexpression by PAβN and cloxacillin susceptibility enhancement, respectively, as well as oprD mutations. From 472 P. aeruginosa clinical isolates (93 patients) and 17 isolates from the ICU environment, high genotypic diversity and several international clones were observed; one environment isolate belonged to the blaSPM-1 P. aeruginosa epidemic genotype. Among isolates from infections, 10 (29%) were carbapenem resistant: none produced carbapenemases, three exhibited all non-carbapenemase mechanisms studied, six presented a combination of two mechanisms, and one exclusively displayed oprD mutations. Carbapenem-resistant P. aeruginosa displayed a polyclonal profile after the SPM-1 epidemic genotype declined. This phenomenon is connected with blaSPM-1 P. aeruginosa replaced by other carbapenem-resistant pathogens.

  3. Microbially Induced Calcite Precipitation Employing Environmental Isolates

    PubMed Central

    Kim, Gunjo; Youn, Heejung

    2016-01-01

    In this study, five microbes were employed to precipitate calcite in cohesionless soils. Four microbes were selected from calcite-precipitating microbes isolated from calcareous sand and limestone cave soils, with Sporosarcina pasteurii ATCC 11859 (standard strain) used as a control. Urease activities of the four microbes were higher than that of S. pasteurii. The microbes and urea–CaCl2 medium were injected at least four times into cohesionless soils of two different relative densities (60% and 80%), and the amount of calcite precipitation was measured. It was found that the relative density of cohesionless soils significantly affects the amount of calcite precipitation and that there is a weak correlation between urease activity and calcite precipitation. PMID:28773600

  4. Isolation, Characterization and Identification of Environmental Bacterial Isolates with Screening for Antagonism Against Three Bacterial Targets

    DTIC Science & Technology

    2017-04-01

    NOMENCLATURE STAPHYLOCOCCUS AUREUS BACTERIA MICROORGANISMS MULTI-DRUG RESISTANT ORGANISMS BIOASSAY CHARACTERIZATION NARROW...5  3.2  Characterization of Activity of Environmental Bacterial Isolates Against the Target Bacteria ...facilitate their future incorporation into materials and textiles. The objective of this work was to isolate a pool of bacteria from the environment

  5. Comparative Evaluation of Two Chromogenic Tests for Rapid Detection of Carbapenemase in Enterobacteriaceae and in Pseudomonas aeruginosa Isolates

    PubMed Central

    Berhin, Catherine; Bogaerts, Pierre; Glupczynski, Youri

    2014-01-01

    We compared the performance of the Carba NP test and the Rosco Rapid CARB screen kit for detecting carbapenemase-producing Enterobacteriaceae and Pseudomonas aeruginosa. Both tests are rapid and highly sensitive; however, the Carba NP test showed superior specificity, and several uninterpretable results were observed with the Rapid CARB screen. PMID:24850357

  6. Complete Genome Sequence of the Triclosan- and Multidrug-Resistant Pseudomonas aeruginosa Strain B10W Isolated from Municipal Wastewater

    PubMed Central

    Zhong, Chuanqing; Nelson, Matthew; Cao, Guangxiang

    2017-01-01

    ABSTRACT Here, we report the complete genome sequence of the triclosan- and multidrug-resistant Pseudomonas aeruginosa strain B10W, obtained from municipal wastewater in Hawaii. The bacterium has a 6.7-Mb genome, contains 6,391 coding sequences and 78 RNAs, with an average G+C content of 66.2 mol%. PMID:28104659

  7. An Integrated Modeling and Experimental Approach to Study the Influence of Environmental Nutrients on Biofilm Formation of Pseudomonas aeruginosa

    PubMed Central

    Xu, Zhaobin; Islam, Sabina; Wood, Thomas K.; Huang, Zuyi

    2015-01-01

    The availability of nutrient components in the environment was identified as a critical regulator of virulence and biofilm formation in Pseudomonas aeruginosa. This work proposes the first systems-biology approach to quantify microbial biofilm formation upon the change of nutrient availability in the environment. Specifically, the change of fluxes of metabolic reactions that were positively associated with P. aeruginosa biofilm formation was used to monitor the trend for P. aeruginosa to form a biofilm. The uptake rates of nutrient components were changed according to the change of the nutrient availability. We found that adding each of the eleven amino acids (Arg, Tyr, Phe, His, Iso, Orn, Pro, Glu, Leu, Val, and Asp) to minimal medium promoted P. aeruginosa biofilm formation. Both modeling and experimental approaches were further developed to quantify P. aeruginosa biofilm formation for four different availability levels for each of the three ions that include ferrous ions, sulfate, and phosphate. The developed modeling approach correctly predicted the amount of biofilm formation. By comparing reaction flux change upon the change of nutrient concentrations, metabolic reactions used by P. aeruginosa to regulate its biofilm formation are mainly involved in arginine metabolism, glutamate production, magnesium transport, acetate metabolism, and the TCA cycle. PMID:25954752

  8. 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

  9. Fingerprint Analysis and Identification of Strains ST309 as a Potential High Risk Clone in a Pseudomonas aeruginosa Population Isolated from Children with Bacteremia in Mexico City.

    PubMed

    Morales-Espinosa, Rosario; Delgado, Gabriela; Espinosa, Luis F; Isselo, Dassaev; Méndez, José L; Rodriguez, Cristina; Miranda, Guadalupe; Cravioto, Alejandro

    2017-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen and is associated with nosocomial infections. Its ability to thrive in a broad range of environments is due to a large and diverse genome of which its accessory genome is part. The objective of this study was to characterize P. aeruginosa strains isolated from children who developed bacteremia, using pulse-field gel electrophoresis, and in terms of its genomic islands, virulence genes, multilocus sequence type, and antimicrobial susceptibility. Our results showed that P. aeruginosa strains presented the seven virulence genes: toxA, lasB, lecA, algR, plcH, phzA1, and toxR, a type IV pilin alleles (TFP) group I or II. Additionally, we detected a novel pilin and accessory gene, expanding the number of TFP alleles to group VI. All strains presented the PAPI-2 Island and the majority were exoU+ and exoS+ genotype. Ten percent of the strains were multi-drug resistant phenotype, 18% extensively drug-resistant, 68% moderately resistant and only 3% were susceptible to all the antimicrobial tested. The most prevalent acquired β-Lactamase was KPC. We identified a group of ST309 strains, as a potential high risk clone. Our finding also showed that the strains isolated from patients with bacteremia have important virulence factors involved in colonization and dissemination as: a TFP group I or II; the presence of the exoU gene within the PAPI-2 island and the presence of the exoS gene.

  10. Fingerprint Analysis and Identification of Strains ST309 as a Potential High Risk Clone in a Pseudomonas aeruginosa Population Isolated from Children with Bacteremia in Mexico City

    PubMed Central

    Morales-Espinosa, Rosario; Delgado, Gabriela; Espinosa, Luis F.; Isselo, Dassaev; Méndez, José L.; Rodriguez, Cristina; Miranda, Guadalupe; Cravioto, Alejandro

    2017-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen and is associated with nosocomial infections. Its ability to thrive in a broad range of environments is due to a large and diverse genome of which its accessory genome is part. The objective of this study was to characterize P. aeruginosa strains isolated from children who developed bacteremia, using pulse-field gel electrophoresis, and in terms of its genomic islands, virulence genes, multilocus sequence type, and antimicrobial susceptibility. Our results showed that P. aeruginosa strains presented the seven virulence genes: toxA, lasB, lecA, algR, plcH, phzA1, and toxR, a type IV pilin alleles (TFP) group I or II. Additionally, we detected a novel pilin and accessory gene, expanding the number of TFP alleles to group VI. All strains presented the PAPI-2 Island and the majority were exoU+ and exoS+ genotype. Ten percent of the strains were multi-drug resistant phenotype, 18% extensively drug-resistant, 68% moderately resistant and only 3% were susceptible to all the antimicrobial tested. The most prevalent acquired β-Lactamase was KPC. We identified a group of ST309 strains, as a potential high risk clone. Our finding also showed that the strains isolated from patients with bacteremia have important virulence factors involved in colonization and dissemination as: a TFP group I or II; the presence of the exoU gene within the PAPI-2 island and the presence of the exoS gene. PMID:28298909

  11. Legionella pneumophila serogroup 12 isolated from human and environmental sources.

    PubMed Central

    Thacker, W L; Wilkinson, H W; Benson, R F; Brenner, D J

    1987-01-01

    A Legionella-like organism (strain 570-CO-H [= ATCC 43290]) isolated from the lung tissue of a patient with pneumonia was shown by growth, as well as physiological, serological, and genetic characteristics, to belong to a new Legionella pneumophila serogroup, serogroup 12. Two additional strains were detected with antiserum specific for strain 570-CO-H. These strains were isolated from environmental sources. PMID:3571461

  12. Outbreak of Pseudomonas aeruginosa bacteraemia in a haematology department.

    PubMed

    Rasmussen, Benjamin Schnack; Christensen, Nikolas; Sørensen, Jan; Rosenvinge, Flemming S; Kolmos, Hans Jørn; Skov, Marianne N

    2015-04-01

    Infection by Pseudomonas aeruginosa represents a major cause of morbidity and mortality among immunocompromised patients. In Denmark, an increase in P. aeruginosa isolates from blood cultures from a haematology department prompted a hygienic audit in 2007. Blood cultures that tested positive for P. aeruginosa were collected from the laboratory information system (MADS, Skejby Hospital, Aarhus, Denmark). Environmental samples were obtained from shower heads in the department. The genotype was established by pulse field gel electrophoresis (PFGE). An audit was conducted during the outbreak and 12 months later. The audits were conducted by the method of direct observation. Several PFGE types were involved with no clear association to isolates from environmental samples. The audit revealed poor hygiene related to the handling of central venous catheters. After optimising catheter hygiene, the number of P. aeruginosa bacteraemia cases fell significantly. Since no clear association between patient and environmental genotype was established, it was suspected that central venous catheters were the main portal of entry. This was further supported by a simultaneous decline in bacteraemia cases with coagulase-negative staphylococci. Though several hygienic precautions were taken, the increased focus on disinfection of hubs and injection ports was presumably the more important element. not relevant. not relevant.

  13. Effect of biosurfactant and fertilizer on biodegradation of crude oil by marine isolates of Bacillus megaterium, Corynebacterium kutscheri and Pseudomonas aeruginosa.

    PubMed

    Thavasi, Rengathavasi; Jayalakshmi, Singaram; Banat, Ibrahim M

    2011-01-01

    This study was conducted to investigate the effects of fertilizers and biosurfactants on biodegradation of crude oil by three marine bacterial isolates; Bacillus megaterium, Corynebacterium kutscheri and Pseudomonas aeruginosa. Five sets of experiments were carried out in shake flask and microcosm conditions with crude oil as follows: Set 1-only bacterial cells added (no fertilizer and biosurfactant), Set 2-with additional fertilizer only, Set 3-with additional biosurfactant only, Set 4-with added biosurfactant+fertilizer, Set 5-with no bacterial cells added (control), all the above experimental sets were incubated for 168 h. The biosurfactant+fertilizer added Set 4, resulted in maximum crude oil degradation within shake flask and microcosm conditions. Among the three bacterial isolates, P. aeruginosa and biosurfactant produced by this strain resulted in maximum crude oil degradation compared to the other two bacterial strains investigated. Interestingly, when biosurfactant and bacterial cells were used (Set 3), significant oil biodegradation activity occurred and the difference between this treatment and that in Set 4 with added fertilizer+biosurfactant were only 4-5% higher degradation level in shake flask and 3.2-7% in microcosm experiments for all three bacterial strains used. It is concluded that, biosurfactants alone capable of promoting biodegradation to a large extent without added fertilizers, which will reduce the cost of bioremediation process and minimizes the dilution or wash away problems encountered when water soluble fertilizers used during bioremediation of aquatic environments.

  14. Molecular characterisation of clinical and environmental isolates of Mycobacterium kansasii isolates from South African gold mines.

    PubMed

    Kwenda, Geoffrey; Churchyard, Gavin J; Thorrold, Catherine; Heron, Ian; Stevenson, Karen; Duse, Adriano G; Marais, Elsé

    2015-03-01

    Mycobacterium kansasii (M. kansasii) is a major cause of non-tuberculous mycobacterial pulmonary disease in the South African gold-mining workforce, but the source of infection and molecular epidemiology are unknown. This study investigated the presence of M. kansasii in gold and coal mine and associated hostel water supplies and compared the genetic diversity of clinical and environmental isolates of M. kansasii. Five M. kansasii and ten other potentially pathogenic mycobacteria were cultured mainly from showerhead biofilms. Polymerase chain reaction-restriction analysis of the hsp65 gene on 196 clinical and environmental M. kansasii isolates revealed 160 subtype I, eight subtype II and six subtype IV strains. Twenty-two isolates did not show the typical M. kansasii restriction patterns, suggesting that these isolates may represent new subtypes of M. kansasii. In contrast to the clonal population structure found amongst the subtype I isolates from studies in other countries, DNA fingerprinting of 114 clinical and three environmental subtype I isolates demonstrated genetic diversity amongst the isolates. This study demonstrated that showerheads are possible sources of M. kansasii and other pathogenic non-tuberculous mycobacterial infection in a gold-mining region, that subtype I is the major clinical isolate of M. kansasii strain and that this subtype exhibits genetic diversity.

  15. Antimicrobial susceptibility of equine and environmental isolates of Clostridium difficile.

    PubMed

    Båverud, V; Gunnarsson, A; Karlsson, M; Franklin, A

    2004-01-01

    The antimicrobial susceptibility of 50 Clostridium difficile isolates, 36 of them from horse feces and 14 from environmental sites, was determined by broth microdilution. The antimicrobial agents tested were avilamycin, cephalothin, chloramphenicol, clindamycin, erythromycin, gentamicin, neomycin, oxacillin, oxytetracycline, penicillin, spiramycin, streptomycin, trimethoprim/sulfamethoxazole, vancomycin, and virginiamycin. All isolates were susceptible to vancomycin (MIC isolates, the MICs of erythromycin (MIC > 16 microg/ml), oxytetracycline (MIC >/=32 microg/ml), spiramycin (MIC > 16 microg/ml), and virginiamycin (MIC 8-16 microg/ml) were higher for 18 isolates. Those were mainly isolated from horses at animal hospitals and further from environmental sites at a stud farm. In contrast, all isolates, except one, from healthy foals had low MICs of erythromycin, spiramycin, virginiamycin, and oxytetracycline. The isolates from soil in public parks had also low MICs of these antimicrobial agents. Broth microdilution appeared both reliable and reproducible for susceptibility testing of C. difficile. The method was also readily performed and the MIC endpoints were easily read.

  16. Pseudomonas aeruginosa in a neonatal intensive care unit: molecular epidemiology and infection control measures

    PubMed Central

    2009-01-01

    Background Pseudomonas aeruginosa, a non-fermentative, gram-negative rod, is responsible for a wide variety of clinical syndromes in NICU patients, including sepsis, pneumonia, meningitis, diarrhea, conjunctivitis and skin infections. An increased number of infections and colonisations by P. aeruginosa has been observed in the neonatal intensive care unit (NICU) of our university hospital between 2005 and 2007. Methods Hand disinfection compliance before and after an educational programme on hand hygiene was evaluated. Identification of microrganisms was performed using conventional methods. Antibiotic susceptibility was evaluated by MIC microdilution. Genotyping was performed by PFGE analysis. Results The molecular epidemiology of Pseudomonas aeruginosa in the NICU of the Federico II University hospital (Naples, Italy) and the infection control measures adopted to stop the spreading of P. aeruginosa in the ward were described. From July 2005 to June 2007, P. aeruginosa was isolated from 135 neonates and caused severe infections in 11 of them. Macrorestriction analysis of clinical isolates from 90 neonates identified 20 distinct genotypes, one major PFGE type (A) being isolated from 48 patients and responsible for 4 infections in 4 of them, four other distinct recurrent genotypes being isolated in 6 to 4 patients. Seven environmental strains were isolated from the hand of a nurse and from three sinks on two occasions, two of these showing PFGE profiles A and G identical to two clinical isolates responsible for infection. The successful control of the outbreak was achieved through implementation of active surveillance of healthcare-associated infections in the ward together with environmental microbiological sampling and an intense educational programme on hand disinfection among the staff members. Conclusion P. aeruginosa infections in the NICU were caused by the cross-transmission of an epidemic clone in 4 neonates, and by the selection of sporadic clones in 7

  17. Green synthesis of Al2O3 nanoparticles and their bactericidal potential against clinical isolates of multi-drug resistant Pseudomonas aeruginosa.

    PubMed

    Ansari, Mohammad A; Khan, Haris M; Alzohairy, Mohammad A; Jalal, Mohammad; Ali, Syed G; Pal, Ruchita; Musarrat, Javed

    2015-01-01

    The high prevalence of extended-spectrum β-lactamases (76.3 %) and metallo-β-lactamases (7.3 %) amongst the bacteria Pseudomonas aeruginosa is a critical problem that has set forth an enormous therapeutic challenge. The suggested role of nanoparticles as next generation antibiotics, and inadequate information on antibacterial activity of aluminium oxide nanoparticles has led us to investigate the green synthesis of aluminium oxide nanoparticles (Al2O3 NPs) using leaf extracts of lemongrass and its antibacterial activity against extended-spectrum β-lactamases and metallo-β-lactamases clinical isolates of P. aeruginosa. The synthesized Al2O3-NPs were characterized by scanning electron microcopy, high resolution-transmission electron microscopy, atomic force microscopy, X-ray diffraction, Zeta potential, and differential light scattering techniques. The X-ray diffraction data revealed the average size of the spherical Al2O3-NPs as 34.5 nm. The hydrodynamic size in Milli Q water and Zeta potential were determined to be 254 nm and +52.2 mV, respectively. The minimal inhibitory concentration of Al2O3-NPs was found to be in the range of 1,600-3,200 µg/ml. Treatment at concentrations >2,000 µg/ml, resulted in complete growth inhibition of extended-spectrum β-lactamases and metallo-β-lactamases isolates. Scanning electron microcopy analysis revealed the clusters of nanoparticles attached to the bacterial cell surface, causing structural deformities in treated cells. High resolution-transmission electron microscopy analysis confirmed that nanoparticles crossed the cell membrane to become intracellular. The interaction of nanoparticles with the cell membrane eventually triggered the loss of membrane integrity, most likely due to intracellular oxidative stress. The data explicitly suggested that the synthesized Al2O3-NPs can be exploited as an effective bactericidal agent against extended-spectrum β-lactamases, non-extended-spectrum β-lactamases and metallo

  18. Successful implementation of infection control strategies prevents P. aeruginosa transmission among cystic fibrosis patients inside the hospital

    PubMed Central

    Matt, Benedikt; Mitteregger, Dieter; Renner, Sabine; Presterl, Elisabeth; Assadian, Ojan; Diab-Elschahawi, Magda

    2014-01-01

    Background: The aim of this study was to characterise the epidemiology of P. aeruginosa isolated from cystic fibrosis (CF) patients at the Vienna General Hospital (VGH) by molecular genetic fingerprinting in order to understand transmission ways and to evaluate the established infection control protocols. Methods: The outpatient clinic for CF patients at the VGH cares for children and adolescents up to the age of 18 years. Among an average of 139 patients cared for at the clinic, 41 were tested positive for P. aeruginosa during the study period. Fifty P. aeruginosa isolates, obtained between August 2010 and March 2012 from routine examinations of CF patients, were subject to molecular characterization using the DiversiLab® method. Results: 42 distinguishable molecular-biological patterns were identified, 7 of which were found multiple times. 40 out of 42 genotypes were retrieved from single patients only, while two patterns were present in two patients each. Nine patients presented with two or more phenotypically diverse P. aeruginosa isolates. In five of these cases the retrieved isolates belonged to the same genotype. Conclusion: The broad genetic heterogeneity of P. aeruginosa in the studied patient population suggests that the majority of CF patients cared for at the VGH acquire P. aeruginosa from environmental sources. It may be concluded that implemented infection control guidelines have been successful in preventing nosocomial transmission of P. aeruginosa among CF patients within the VGH and patient-to-patient transmission outside the hospital. Chronic polyclonal infection/colonization was rare in the study population. PMID:25285264

  19. Waste Isolation Pilot Plant Annual Site Environmental Report for 2010

    SciTech Connect

    2011-09-01

    The purpose of the Waste Isolation Pilot Plant (WIPP) Annual Site Environmental Report for 2010 (ASER) is to provide information required by U.S. Department of Energy (DOE) Order 231.1A, Environment, Safety, and Health Reporting. Specifically, the ASER presents summary environmental data to: (1) Characterize site environmental management performance. (2) Summarize environmental occurrences and responses reported during the calendar year. (3) Confirm compliance with environmental standards and requirements. (4) Highlight significant environmental accomplishments, including progress toward the DOE Environmental Sustainability Goals made through implementation of the WIPP Environmental Management System (EMS). The DOE Carlsbad Field Office (CBFO) and the management and operating contractor (MOC), Washington TRU Solutions LLC (WTS), maintain and preserve the environmental resources at the WIPP. DOE Order 231.1A; DOE Order 450.1A, Environmental Protection Program; and DOE Order 5400.5, Radiation Protection of the Public and the Environment, require that the affected environment at and near DOE facilities be monitored to ensure the safety and health of the public and workers, and preservation of the environment. This report was prepared in accordance with DOE Order 231.1A, which requires that DOE facilities submit an ASER to the DOE Headquarters Chief Health, Safety, and Security Officer. The WIPP Hazardous Waste Facility Permit Number NM4890139088-TSDF (Permit) further requires that the ASER be provided to the New Mexico Environment Department (NMED).

  20. Waste Isolation Pilot Plant Biennial Environmental Compliance Report

    SciTech Connect

    Washington Regulatory and Environmental Services

    2004-10-25

    This Biennial Environmental Compliance Report (BECR) documents environmental regulatory compliance at the Waste Isolation Pilot Plant (WIPP), a facility designed and authorized for the safe disposal of transuranic (TRU) radioactive waste, for the reporting period of April 1, 2002, to March 31, 2004. As required by the WIPP Land Withdrawal Act (LWA) (Public Law [Pub. L.] 102-579, as amended by Pub. L. 104-201), the BECR documents U.S. Department of Energy (DOE) compliance with applicable environmental protection laws and regulations implemented by agencies of the federal government and the state of New Mexico.

  1. Efflux-mediated fluoroquinolone resistance in the multidrug-resistant Pseudomonas aeruginosa clinical isolate PA7: identification of a novel MexS variant involved in upregulation of the mexEF-oprN multidrug efflux operon

    PubMed Central

    Morita, Yuji; Tomida, Junko; Kawamura, Yoshiaki

    2014-01-01

    The emergence of multidrug-resistant Pseudomonas aeruginosa has become a serious problem in medical settings. P. aeruginosa clinical isolate PA7 is resistant to fluoroquinolones, aminoglycosides, and most β-lactams but not imipenem. In this study, enhanced efflux-mediated fluoroquinolone resistance of PA7 was shown to reflect increased expression of two resistance nodulation cell division (RND) -type multidrug efflux operons, mexEF-oprN and mexXY-oprA. Such a clinical isolate has rarely been reported because MexEF-OprN-overproducing mutants often increase susceptibility to aminoglycosides apparently owing to impairment of the MexXY system. A mutant of PA7 lacking three RND-type multidrug efflux operons (mexAB-oprM, mexEF-oprN, and mexXY-oprA) was susceptible to all anti-pseudomonas agents we tested, supporting an idea that these RND-type multidrug efflux transporters are molecular targets to overcome multidrug resistance in P. aeruginosa. mexEF-oprN-upregulation in P. aeruginosa PA7 was shown due to a MexS variant harboring the Valine-155 amino acid residue. This is the first genetic evidence shown that a MexS variant causes mexEF-oprN-upregulation in P. aeruginosa clinical isolates. PMID:25653649

  2. Genotypic diversity of environmental Cryptococcus neoformans isolates from Northern Portugal.

    PubMed

    Ferreira, Ana Sofia; Sampaio, Ana; Maduro, Ana Paula; Silva, Inês; Teles, Fernando; Martins, Maria da Luz; Inácio, João

    2014-02-01

    The Cryptococcus neoformans/C. gattii species complex members are the main agents of systemic cryptococcosis. This disease is believed to be acquired from the environment via fungal cell inhalation. Often, isolates recovered from environmental and clinical sources have proven to be genotypically similar. We assessed the occurrence of C. neoformans and C. gattii in environmental substrates collected in a Portuguese region. Twenty-eight isolates were identified as C. neoformans - five from decaying Eucalyptus leaves and 23 from domestic pigeon droppings. The isolates were genotyped using a URA5-RFLP approach. The C. neoformans VNIV (53.6%, n = 15) and VNI (32.1%, n = 9) genotypes were abundantly present among environmental isolates. The hybrid VNIII (14.3%, n = 4) genotype was underrepresented and the VNII was not found. Cryptococcus gattii was also not found although some isolates yielded a positive canavanine-glycine-bromothymol blue test.

  3. Waste Isolation Pilot Plant Site Environmental Report Calendar Year 2002

    SciTech Connect

    Washington Regulatory and Environmental Services

    2003-09-17

    The United States (U.S.) Department of Energy (DOE) Carlsbad Field Office (CBFO) and Washington TRU Solutions LLC (WTS) are dedicated to maintaining high quality management of Waste Isolation Pilot Plant (WIPP) environmental resources. DOE Order 5400.1, General Environmental Protection Program, and DOE Order 231.1, Environment, Safety, and Health Reporting, require that the environment at and near DOE facilities be monitored to ensure the safety and health of the public and the environment. This Waste Isolation Pilot Plant 2002 Site Environmental Report summarizes environmental data from calendar year 2002 that characterize environmental management performance and demonstrate compliance with federal and state regulations. This report was prepared in accordance with DOE Order 5400.1, DOE Order 231.1, and Guidance for the Preparation of DOE Annual Site Environmental Reports (ASERs) for Calendar Year 2002 (DOE Memorandum EH-41: Natoli:6-1336, April 4, 2003). These Orders and the guidance document require that DOE facilities submit an annual site environmental report to DOE Headquarters, Office of the Assistant Secretary for Environment, Safety, and Health; and the New Mexico Environment Department (NMED).

  4. Construction and characterization of a highly redundant Pseudomonas aeruginosa genomic library prepared from 12 clinical isolates: application to studies of gene distribution among populations

    PubMed Central

    Erdos, Geza; Sayeed, Sameera; Hu, Fen Ze; Antalis, Patricia T.; Shen, Kai; Hayes, Jay D.; Ahmed, Azad I.; Johnson, Sandra L.; Post, J. Christopher; Ehrlich, Garth D.

    2006-01-01

    Objective To create, array, and characterize a pooled, high-coverage, genomic library composed of multiple biofilm-forming clinical strains of the opportunistic pathogen, Pseudomonas aeruginosa (PA). Twelve strains were obtained from patients with otorrhea, otitis media, and cystic fibrosis as a resource for investigating: difference in the transcriptomes of planktonic and biofilm envirovars; the size of the PA supragenome and determining the number of virulence genes available at the population level; and for testing the distributed genome hypothesis. Methods High molecular weight genomic DNAs from twelve clinical PA strains were individually hydrodynamically sheared to produce mean fragment sizes of ~1.5Kb. Equimolar amounts of the 12 sheared genomic DNAs were then pooled and used in the construction of a genomic library with ~250,000 clones that was arrayed and subjected to quality control analyses. Results Restriction endonuclease and sequence analyses of 686 clones picked at random from the library demonstrated that >75% of the clones contained inserts larger than 0.5 Kb with the desired mean insert size of 1.4 Kb. Thus, this library provides better than 4.5x coverage for each of the genomes from the twelve component clinical PA isolates. Our sequencing effort (~1 million nucleotides to date) reveals that 13% of the clones present in this library are not represented in the genome of the reference P. aeruginosa strain PA01. Conclusions Our data suggests that reliance on a single laboratory strain, such as PA01, as being representative of a pathogenic bacterial species will fail to identify many important genes, and that to obtain a complete picture of complex phenomena, including bacterial pathogenesis and the genetics of biofilm development will require characterization of the P. aeruginosa population-based supra-genome. PMID:16899304

  5. Antibiotic resistance pattern and evaluation of metallo-beta lactamase genes (VIM and IMP) in Pseudomonas aeruginosa strains producing MBL enzyme, isolated from patients with secondary immunodeficiency.

    PubMed

    Shirani, Kiana; Ataei, Behrouz; Roshandel, Fardad

    2016-01-01

    One of the most common causes of hospital-acquired secondary infections in hospitalized patients is Pseudomonas aeruginosa. The aim of this study is to evaluate the expression of IMP and VIM in Pseudomonas aeruginosa strains (carbapenem resistant and producer MBL enzyme) in patients with secondary immunodeficiency. In a cross sectional study, 96 patients with secondary immunodeficiency hospitalized in the Al-Zahra hospital were selected. Carbapenem resistant strains isolated and modified Hodge test was performed in order to confirm the presence of the metallo carbapenemase enzyme. Under the standard conditions they were sent to the central laboratory for investigating nosocomial infection Multiplex PCR. Of 96 samples 28.1% were IMP positive, 5.2% VIM positive and 3.1% both VIM and IMP positive. The prevalence of multidrug resistance in the IMP and/or VIM negative samples was 29%, while all 5 VIM positive samples have had multidrug resistance. Also the prevalence of multi-drug resistance in IMP positive samples were 96.3% and in IMP and VIM positive samples were 100%. According to Fisher's test, the prevalence of multi-drug resistance based on gene expression has significant difference (P < 0.001). Based on the results of this study it can be concluded that, a significant percentage of patients with secondary immunodeficiency that suffer nosocomial infections with multidrug resistance, especially Pseudomonas aeruginosa, are probably MBL-producing gene positive. Therefore the cause of infection should be considered in the hospital care system to identify their features, the presence of genes involved in the development of multi-drug resistance and antibiotic therapy.

  6. Antibiotic resistance pattern and evaluation of metallo-beta lactamase genes (VIM and IMP) in Pseudomonas aeruginosa strains producing MBL enzyme, isolated from patients with secondary immunodeficiency

    PubMed Central

    Shirani, Kiana; Ataei, Behrouz; Roshandel, Fardad

    2016-01-01

    Background: One of the most common causes of hospital-acquired secondary infections in hospitalized patients is Pseudomonas aeruginosa. The aim of this study is to evaluate the expression of IMP and VIM in Pseudomonas aeruginosa strains (carbapenem resistant and producer MBL enzyme) in patients with secondary immunodeficiency. Materials and Methods: In a cross sectional study, 96 patients with secondary immunodeficiency hospitalized in the Al-Zahra hospital were selected. Carbapenem resistant strains isolated and modified Hodge test was performed in order to confirm the presence of the metallo carbapenemase enzyme. Under the standard conditions they were sent to the central laboratory for investigating nosocomial infection Multiplex PCR. Results: Of 96 samples 28.1% were IMP positive, 5.2% VIM positive and 3.1% both VIM and IMP positive. The prevalence of multidrug resistance in the IMP and/or VIM negative samples was 29%, while all 5 VIM positive samples have had multidrug resistance. Also the prevalence of multi-drug resistance in IMP positive samples were 96.3% and in IMP and VIM positive samples were 100%. According to Fisher’s test, the prevalence of multi-drug resistance based on gene expression has significant difference (P < 0.001). Conclusion: Based on the results of this study it can be concluded that, a significant percentage of patients with secondary immunodeficiency that suffer nosocomial infections with multidrug resistance, especially Pseudomonas aeruginosa, are probably MBL-producing gene positive. Therefore the cause of infection should be considered in the hospital care system to identify their features, the presence of genes involved in the development of multi-drug resistance and antibiotic therapy. PMID:27563634

  7. Predominance of carbapenem-resistant Pseudomonas aeruginosa isolates carrying blaIMP and blaVIM metallo-β-lactamases in a major hospital in Costa Rica.

    PubMed

    Toval, Francisco; Guzmán-Marte, Anel; Madriz, Vivian; Somogyi, Teresita; Rodríguez, César; García, Fernando

    2015-01-01

    This study aimed to assess the molecular basis of the resistance to carbapenems in clinical isolates of Pseudomonas aeruginosa recovered from a tertiary-level health facility in San José, Costa Rica. A total of 198 non-duplicated isolates were evaluated for their susceptibility to β-lactams, aminoglycosides and fluoroquinolones. The production of metallo-β-lactamases (MBLs), the presence of MBL encoding genes (blaIMP, blaVIM and blaGIM-1) and the occurrence of these genes within class 1 integrons were investigated. In addition, an ERIC2 PCR fingerprinting method was used to elucidate the distribution of the detected MBL genes within the strain collection. Of the 198 isolates tested, 125 (63.1 %) were categorized as carbapenem-resistant. The majority (88.8 %) of the carbapemen-resistant isolates also showed resistance to ceftazidime, cefepime, aztreonam, ticarcillin/clavulanic acid, amikacin, gentamicin, tobramycin, ciprofloxacin and gatifloxacin. Among the carbapenem-resistant isolates, 102 (81.6 %) showed MBL activity. Strikingly, both blaIMP and blaVIM genes were simultaneously detected in most (94.1 %) of the 102 MBL producers. Five carbapenem-resistant MBL producers were positive only for blaIMP genes. Almost 70 % of the isolates examined harboured the intI1 gene, accompanied by the sul1 and qacEΔ1 genes in 136 (99 %) and 122 (89 %) isolates, respectively. The majority (94.4 %) of the carbapenem-resistant isolates carried the intI1 gene, in contrast to 26 % of the carbapenem-susceptible isolates. Ninety-three out of 96 (96.9 %) isolates carrying both blaIMP and blaVIM genes also harboured the intI1, sul1 and qacEΔ1 genes. Gene cassettes from carbapenem-susceptible and MBL-negative carbapenem-resistant isolates encoded aminoglycoside-resistance enzymes (aadA2, aadA4 and aadA6) as well as orfD and qacF genes. RAPD analysis distributed 126 of the isolates in 29 clusters. Eighty of the 90 blaIMP (+) blaVIM (+) isolates were sorted into 16

  8. A major Pseudomonas aeruginosa clone common to patients and aquatic habitats.

    PubMed Central

    Römling, U; Wingender, J; Müller, H; Tümmler, B

    1994-01-01

    The genomic relatedness of 573 Pseudomonas aeruginosa strains from environmental and clinical habitats was examined by digesting the genome with the rare-cutting enzyme SpeI. Thirty-nine strains were collected from environmental habitats mainly of aquatic origin, like rivers, lakes, or sanitary facilities. Four hundred fifty strains were collected from 76 patients with cystic fibrosis (CF) treated at four different centers, and 25 additional clinical isolates were collected from patients suffering from other diseases. Twenty-nine P. aeruginosa isolates were collected from the environment of one CF clinic. Thirty strains from culture collections were of environmental and clinic origin. A common macrorestriction fingerprint pattern was found in 13 of 46 CF patients, 5 of 29 environmental isolates from the same hospital, in a single ear infection isolate from another hospital, and 8 of 38 isolates from aquatic habitats about 300 km away from the CF clinic. The data indicate that closely related variants of one major clone (called clone C) persisted in various spatially and temporally separated habitats. Southern analysis of the clonal variants with six gene probes and two probes for genes coding for rRNA revealed almost the same hybridization patterns. With the exception of the phenotypically rapidly evolving CF isolates, the close relatedness of the strains of the clone was also shown by their identical responses in pyocin typing, phage typing, and serotyping. Besides clone C, three other P. aeruginosa clones were isolated from more than one clinical or environmental source. Images PMID:8031075

  9. In vitro potentiation of carbapenems with ME1071, a novel metallo-beta-lactamase inhibitor, against metallo-beta-lactamase- producing Pseudomonas aeruginosa clinical isolates.

    PubMed

    Ishii, Yoshikazu; Eto, Maki; Mano, Yoko; Tateda, Kazuhiro; Yamaguchi, Keizo

    2010-09-01

    ME1071, a maleic acid derivative, is a novel specific inhibitor for metallo-beta-lactamases (MBL). In this study, the potentiation of ME1071 in combination with several beta-lactams was evaluated using MBL-producing Pseudomonas aeruginosa isolates. The rates of susceptibility of MBL producers to carbapenems (imipenem, biapenem, and doripenem) and ceftazidime were increased by 8 to 27% in the presence of 32 microg/ml of ME1071. The corresponding resistance rates were decreased by 13 to 46%, respectively. On the other hand, ME1071 showed weaker or no potentiation with non-MBL producers. The K(i) value of ME1071 for IMP-1 was 0.4 microM, significantly lower than the K(m) values of carbapenems for the IMP-1 enzyme. On the other hand, the K(i) value of ME1071 for VIM-2 was 120 microM, higher than the K(m) values of carbapenems for the VIM-2 enzyme. Results of this study indicate that ME1071 can potentiate the activity of ceftazidime and carbapenems against MBL-producing strains of P. aeruginosa.

  10. Genomic Characterization of Human and Environmental Polioviruses Isolated in Albania

    PubMed Central

    Divizia, Maurizio; Palombi, Leonardo; Buonomo, Ersilia; Donia, Domenica; Ruscio, Vito; Equestre, Michele; Leno, Luljeta; Panà, Augusto; Degener, Anna Marta

    1999-01-01

    Between April and December 1996, a serious outbreak of poliomyelitis occurred in Albania; almost 140 subjects were involved, and the episode presented an unusually high mortality rate (12%). During the outbreak, water samples from the Lana River in Tirana, Albania, and stool samples from two cases of paralytic poliomyelitis were collected and analyzed for the presence of polioviruses. Six polioviruses were isolated from the environmental and human samples, according to standard methods. All the samples were characterized by partial genomic sequencing of 330 bases across the 5′ untranslated region (5′-UTR) (nucleotide positions 200 to 530) and of 300 bases across the VP1 region (nucleotide positions 2474 to 2774). Comparison of these sequences with those present in data banks permitted the identification of environmental isolates Lana A and Lana B as, respectively, a Sabin-like type 2 poliovirus and an intertypic recombinant poliovirus (Sabin-like type 2/wild type 1), both bearing a G instead of an A at nucleotide position 481. The two other environmental polioviruses were similar to the isolates from the paralytic cases. They were characterized by a peculiar 5′-UTR and by a VP1 region showing 98% homology with the Albanian epidemic type 1 isolates reported by other authors. This study confirms the environmental circulation in Albania of recombinant poliovirus strains, likely sustained by a massive vaccination effort and by the presence in the environment of a type 1 poliovirus, as isolated from the Lana River in Tirana about 2 months before the first case of symptomatic acute flaccid paralysis was reported in this town. PMID:10427045

  11. Draft Genome Sequence of Textile Azo Dye-Decolorizing and -Degrading Pseudomonas aeruginosa Strain PFK10, Isolated from the Common Effluent Treatment Plant of the Ankleshwar Industrial Area of Gujarat, India.

    PubMed

    Faldu, P R; Kothari, V V; Kothari, C R; Rawal, C M; Domadia, K K; Patel, P A; Bhimani, H D; Raval, V H; Parmar, N R; Nathani, N M; Koringa, P G; Joshi, C G; Kothari, R K

    2014-02-06

    Here, we report the draft genome sequence of Pseudomonas aeruginosa strain PFK10, isolated from the common effluent treatment plant (CETP) of the Ankleshwar industrial area of Gujarat, India. The 6.04-Mb draft genome sequence of strain PFK10 provides information about the genes encoding enzymes that enable the strain to decolorize and degrade textile azo dye.

  12. Draft Genome Sequence of Textile Azo Dye-Decolorizing and -Degrading Pseudomonas aeruginosa Strain PFK10, Isolated from the Common Effluent Treatment Plant of the Ankleshwar Industrial Area of Gujarat, India

    PubMed Central

    Faldu, P. R.; Kothari, V. V.; Kothari, C. R.; Rawal, C. M.; Domadia, K. K.; Patel, P. A.; Bhimani, H. D.; Raval, V. H.; Parmar, N. R.; Nathani, N. M.; Koringa, P. G.; Joshi, C. G.

    2014-01-01

    Here, we report the draft genome sequence of Pseudomonas aeruginosa strain PFK10, isolated from the common effluent treatment plant (CETP) of the Ankleshwar industrial area of Gujarat, India. The 6.04-Mb draft genome sequence of strain PFK10 provides information about the genes encoding enzymes that enable the strain to decolorize and degrade textile azo dye. PMID:24503984

  13. First detection of insertion sequence element ISPa1328 in the oprD porin gene of an imipenem-resistant Pseudomonas aeruginosa isolate from an idiopathic pulmonary fibrosis patient in Marseille, France

    PubMed Central

    Al-Bayssari, C.; Valentini, C.; Gomez, C.; Reynaud-Gaubert, M.; Rolain, J.-M.

    2015-01-01

    We report here the first case of a carbapenem-resistant Pseudomonas aeruginosa clinical isolate harboring the insertion sequence (IS) element ISPa1328 in the oprD gene in an idiopathic pulmonary fibrosis patient in France previously treated with imipenem. PMID:26137309

  14. Pre-adapting parasitic phages to a pathogen leads to increased pathogen clearance and lowered resistance evolution with Pseudomonas aeruginosa cystic fibrosis bacterial isolates.

    PubMed

    Friman, V-P; Soanes-Brown, D; Sierocinski, P; Molin, S; Johansen, H K; Merabishvili, M; Pirnay, J-P; De Vos, D; Buckling, A

    2016-01-01

    Recent years have seen renewed interest in phage therapy--the use of viruses to specifically kill disease-causing bacteria--because of the alarming rise in antibiotic resistance. However, a major limitation of phage therapy is the ease at with bacteria can evolve resistance to phages. Here, we determined whether in vitro experimental coevolution can increase the efficiency of phage therapy by limiting the resistance evolution of intermittent and chronic cystic fibrosis Pseudomonas aeruginosa lung isolates to four different phages. We first pre-adapted all phage strains against all bacterial strains and then compared the efficacy of pre-adapted and nonadapted phages against ancestral bacterial strains. We found that evolved phages were more efficient in reducing bacterial densities than ancestral phages. This was primarily because only 50% of bacterial strains were able to evolve resistance to evolved phages, whereas all bacteria were able to evolve some level of resistance to ancestral phages. Although the rate of resistance evolution did not differ between intermittent and chronic isolates, it incurred a relatively higher growth cost for chronic isolates when measured in the absence of phages. This is likely to explain why evolved phages were more effective in reducing the densities of chronic isolates. Our data show that pathogen genotypes respond differently to phage pre-adaptation, and as a result, phage therapies might need to be individually adjusted for different patients. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

  15. Waset Isolation Pilot Plant Annual Site Environmental Report for 2006

    SciTech Connect

    Washington Regulatory and Environmental Services; Washington TRU Solutions LLC

    2007-09-26

    The purpose of the Waste Isolation Pilot Plant Annual Site Environmental Report for 2006 (ASER) is to provide information required by U.S. Department of Energy (DOE) Order 231.1A, Environment, Safety, and Health Reporting. Specifically, the ASER presents summary environmental data that: (a) Characterize site environmental management performance; (b) Summarize environmental occurrences and responses reported during the calendar year; (c) Confirm compliance with environmental standards and requirements; and (d) Highlight significant facility programs and efforts. The DOE Carlsbad Field Office (CBFO) and Washington TRU Solutions LLC (WTS) maintain and preserve the environmental resources at the WIPP site. DOE Order 231.1A; DOE Order 450.1, Environmental Protection Program; and DOE Order 5400.5, Radiation Protection of the Public and Environment, require that the affected environment at and near DOE facilities be monitored to ensure the safety and health of the public and the environment. This report was prepared in accordance with DOE Order 231.1A. This order requires that DOE facilities submit an ASER to the DOE Headquarters Office of the Assistant Secretary for Environment, Safety, and Health. The WIPP Hazardous Waste Facility Permit (HWFP) (No. NM4890139088-TSDF [treatment, storage, and disposal facility]) further requires that the ASER be provided to the New Mexico Environment Department (NMED).

  16. Dexamethasone abrogates the antimicrobial and antibiofilm activities of different drugs against clinical isolates of Staphylococcus aureus and Pseudomonas aeruginosa.

    PubMed

    Rodrigues, Aquila; Gomes, André; Marçal, Pedro Henrique Ferreira; Dias-Souza, Marcus Vinícius

    2017-01-01

    Staphylococcus aureus and Pseudomonas aeruginosa are part of the human microbiota and are also important bacterial pathogens, for which therapeutic options are lacking nowadays. The combined administration of corticosteroids and antimicrobials is commonly used in the treatment of infectious diseases to control inflammatory processes and to minimize potential toxicity of antimicrobials, avoiding sequelae. Although different pharmaceutical dosage forms of antimicrobials combined to corticosteroids are available, studies on the interference of corticosteroids on the pharmacological activity of antimicrobials are scarce and controversial. Here, we provide evidence of the interference of dexamethasone on the pharmacological activity of clinically important antimicrobial drugs against biofilms and planktonic cells of S. aureus and P. aeruginosa. Broth microdilution assays of minimal inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum biofilm eradication concentration (MBEC) of gentamicin, chloramphenicol, oxacillin, ceftriaxone and meropenem were conducted with and without the addition of dexamethasone. The effect of all drugs was abrogated by dexamethasone in their MIC, MBC, and MBEC, except gentamicin and meropenem, for which the MBC was not affected in some strains. The present study opens doors for more investigations on in vitro and in vivo effects and safety of the combination of antimicrobials and glucocorticoids.

  17. Type II Topoisomerase Mutations in Fluoroquinolone-Resistant Clinical Strains of Pseudomonas aeruginosa Isolated in 1998 and 1999: Role of Target Enzyme in Mechanism of Fluoroquinolone Resistance

    PubMed Central

    Akasaka, Takaaki; Tanaka, Mayumi; Yamaguchi, Akihito; Sato, Kenichi

    2001-01-01

    The major mechanism of resistance to fluoroquinolones for Pseudomonas aeruginosa is the modification of type II topoisomerases (DNA gyrase and topoisomerase IV). We examined the mutations in quinolone-resistance-determining regions (QRDR) of gyrA, gyrB, parC, and parE genes of recent clinical isolates. There were 150 isolates with reduced susceptibilities to levofloxacin and 127 with reduced susceptibilities to ciprofloxacin among 513 isolates collected during 1998 and 1999 in Japan. Sequencing results predicted replacement of an amino acid in the QRDR of DNA gyrase (GyrA or GyrB) for 124 of the 150 strains (82.7%); among these, 89 isolates possessed mutations in parC or parE which lead to amino acid changes. Substitutions of both Ile for Thr-83 in GyrA and Leu for Ser-87 in ParC were the principal changes, being detected in 48 strains. These replacements were obviously associated with reduced susceptibilities to levofloxacin, ciprofloxacin, and sparfloxacin; however, sitafloxacin showed high activity against isolates with these replacements. We purified GyrA (The-83 to Ile) and ParC (Ser-87 to Leu) by site-directed mutagenesis and compared the inhibitory activities of the fluoroquinolones. Sitafloxacin showed the most potent inhibitory activities against both altered topoisomerases among the fluoroquinolones tested. These results indicated that, compared with other available quinolones, sitafloxacin maintained higher activity against recent clinical isolates with multiple mutations in gyrA and parC, which can be explained by the high inhibitory activities of sitafloxacin against both mutated enzymes. PMID:11451683

  18. Pseudomonas aeruginosa Exhibits Frequent Recombination, but Only a Limited Association between Genotype and Ecological Setting

    PubMed Central

    Kidd, Timothy J.; Ritchie, Stephen R.; Ramsay, Kay A.; Grimwood, Keith; Bell, Scott C.; Rainey, Paul B.

    2012-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen and an important cause of infection, particularly amongst cystic fibrosis (CF) patients. While specific strains capable of patient-to-patient transmission are known, many infections appear to be caused by unique and unrelated strains. There is a need to understand the relationship between strains capable of colonising the CF lung and the broader set of P. aeruginosa isolates found in natural environments. Here we report the results of a multilocus sequence typing (MLST)-based study designed to understand the genetic diversity and population structure of an extensive regional sample of P. aeruginosa isolates from South East Queensland, Australia. The analysis is based on 501 P. aeruginosa isolates obtained from environmental, animal and human (CF and non-CF) sources with particular emphasis on isolates from the Lower Brisbane River and isolates from CF patients obtained from the same geographical region. Overall, MLST identified 274 different sequence types, of which 53 were shared between one or more ecological settings. Our analysis revealed a limited association between genotype and environment and evidence of frequent recombination. We also found that genetic diversity of P. aeruginosa in Queensland, Australia was indistinguishable from that of the global P. aeruginosa population. Several CF strains were encountered frequently in multiple ecological settings; however, the most frequently encountered CF strains were confined to CF patients. Overall, our data confirm a non-clonal epidemic structure and indicate that most CF strains are a random sample of the broader P. aeruginosa population. The increased abundance of some CF strains in different geographical regions is a likely product of chance colonisation events followed by adaptation to the CF lung and horizontal transmission among patients. PMID:22970178

  19. Sensitivity to Antimicrobial Drugs of Pseudomonas Aeruginosa Extreme-Resistant Strains Isolated in the Major Hospitals of Central Kazakhstan

    PubMed Central

    Azizov, Ilya S.; Lavrinenko, Alyona V.; Belyaev, Ilya A.; Babenko, Dmitry B.; Shambilova, Natalya A.; Bissenova, Nelya M.

    2017-01-01

    AIM: The article presents the current data on the sensitivity of the main 37 strains of eXtremaly Drugs Resistance (XDR) category to anti-pseudomonas drugs. MATERIAL AND METHODS: The strains were collected during the prospective multicenter study in large multidisciplinary hospitals of Central Kazakhstan. Susceptibility to antimicrobial drugs was carried out by disk method and the serial dilution method with the interpretation of the results according to EUCAST criteria. Detection of carbapenemases gene of VIM, IMP, NDM and GES classes was carried out by PCR method using the commercial kits. RESULTS: All identified carbapenemases were sorted to VIM class and accounted for 63.64%. Resistance to aminoglycoside drugs exceeded 80%. All the strains were susceptible to polymyxin. CONCLUSION: Thus, at the present stage the circulation of P. aeruginosa strains of XDR category continues in major hospitals in Kazakhstan. The strains remain sensitiveness only to polymyxin. PMID:28293307

  20. High-level resistance to meropenem in clinical isolates of Pseudomonas aeruginosa in the absence of carbapenemases: role of active efflux and porin alterations.

    PubMed

    Chalhoub, Hussein; Sáenz, Yolanda; Rodriguez-Villalobos, Hector; Denis, Olivier; Kahl, Barbara C; Tulkens, Paul M; Van Bambeke, Françoise

    2016-12-01

    High-level carbapenem resistance is worryingly increasing in clinical isolates and is often attributed to carbapenemase expression. This study aimed to determine the mechanisms leading to high-level meropenem resistance in six carbapenemase-negative Pseudomonas aeruginosa isolated from cystic fibrosis (CF) patients and seven carbapenemase-positive isolates from patients suffering from hospital-acquired pneumonia (HAP). MICs were determined in the absence or presence of l-arginine or glycine-glutamate as competitive substrates for OprD (OccD1) or OpdP (OccD3), respectively, or the efflux pump inhibitor Phe-Arg β-naphthylamide (PAβN). β-Lactamases were screened by phenotypic tests and/or PCR. The oprD gene and its promoter were sequenced; protein expression was evidenced by SDS-PAGE. mexA, mexX, mexC and mexE transcripts were evaluated by real-time and semiquantitative PCR. Meropenem/imipenem MICs were 64-128/16-32 mg/L and 128/128-256 mg/L in CF and HAP isolates, respectively; PAβN reduced meropenem MICs to 4-16 mg/L only and specifically in CF isolates; porin competitors had no effect on MICs. All isolates showed an increase in transcription levels of mexA, mexX and/or mexC and mutations in oprD leading to production of truncated proteins. AmpC-type cephalosporinases were overexpressed in CF isolates and VIM-2 was expressed in HAP isolates. Antibiotic exclusion from bacteria by concomitant efflux and reduced uptake is sufficient to confer high-level resistance to meropenem in isolates overexpressing AmpC-type cephalosporinases. As efflux is preponderant in these isolates, it confers a paradoxical phenotype where meropenem is less active than imipenem. Concomitant susceptibility testing of both carbapenems and rapid elucidation of the most probable resistance mechanisms is thus warranted. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

  1. Minimum inhibitory concentration distribution in environmental Legionella spp. isolates.

    PubMed

    Sandalakis, Vassilios; Chochlakis, Dimosthenis; Goniotakis, Ioannis; Tselentis, Yannis; Psaroulaki, Anna

    2014-12-01

    In Greece standard tests are performed in the watering and cooling systems of hotels' units either as part of the surveillance scheme or following human infection. The purpose of this study was to establish the minimum inhibitory concentration (MIC) distributions of environmental Legionella isolates for six antimicrobials commonly used for the treatment of Legionella infections, by MIC-test methodology. Water samples were collected from 2004 to 2011 from 124 hotels from the four prefectures of Crete (Greece). Sixty-eight (68) Legionella isolates, comprising L. pneumophila serogroups 1, 2, 3, 5, 6, 8, 12, 13, 15, L. anisa, L. rubrilucens, L. maceachernii, L. quinlivanii, L. oakridgensis, and L. taurinensis, were included in the study. MIC-tests were performed on buffered charcoal yeast extract with α-ketoglutarate, L-cysteine, and ferric pyrophosphate. The MICs were read after 2 days of incubation at 36 ± 1 °C at 2.5% CO2. A large distribution in MICs was recorded for each species and each antibiotic tested. Rifampicin proved to be the most potent antibiotic regardless of the Legionella spp.; tetracycline appeared to have the least activity on our environmental isolates. The MIC-test approach is an easy, although not so cost-effective, way to determine MICs in Legionella spp. These data should be kept in mind especially since these Legionella species may cause human disease.

  2. Melittin and its potential in the destruction and inhibition of the biofilm formation by Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa isolated from bovine milk.

    PubMed

    Picoli, Tony; Peter, Cristina Mendes; Zani, João Luíz; Waller, Stefanie Bressan; Lopes, Matheus Gomes; Boesche, Kamilla Neutzling; Vargas, Gilberto D Ávila; Hübner, Silvia de Oliveira; Fischer, Geferson

    2017-09-21

    Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa stand out in veterinary and human medicine for their role in opportunistic infections and their pathogenic mechanisms, including the biofilms formation. It was investigated the antibacterial activity of melittin and antibiofilm of such bacteria. Twelve strains of these microorganisms isolated from bovine milk were used, as well as the strains S. aureus ATCC 12600, E. coli ATCC 8739 and Pseudomonas aeruginosa ATCC 15442. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentration (MBC) were determined by broth microdilution technique. The biofilms were formed in 96-well plates and melittin on these colonies was added at different concentrations and times. Bacteria previously exposed to melittin were evaluated for inhibition of biofilm production. The MIC and MBC were respectively in μg/mL: S. aureus (6-7 and 32-64), E. coli (40-42.5 and 64-128) and P. aeruginosa (65-70 and 64-128). S. aureus biofilms were more sensitive to the action of melittin, since upon exposure to a concentration 10 times lower than the MIC for 4 h, was completely destroyed. In Gram negative bacteria, the pre-formed biofilm was destroyed only when exposed for 4 h under the MIC. With respect to inhibition of biofilm production, S. aureus was the most sensitive again because produced only 37.2% of the biofilm formed by the control (without previous exposure to melittin), when exposed to the MIC, and at a concentration hundred times smaller than MIC, this microorganism produced 75.2% of the biofilm. E. coli was the most resistant bacteria and produced 56.3% of the biofilm, even if previously exposed to melittin MIC. Melittin presents desirable effects in combating microorganisms studied both at your disposal, biofilm destruction and inhibition of the formation, and maybe used in future studies of new strategies to combat infections caused by these pathogens. Copyright © 2017 Elsevier Ltd. All

  3. Kinetics of nutrient enhanced crude oil degradation by Pseudomonas aeruginosa AKS1 and Bacillus sp. AKS2 isolated from Guwahati refinery, India.

    PubMed

    Chettri, Bobby; Mukherjee, Arghya; Langpoklakpam, James S; Chattopadhyay, Dhrubajyoti; Singh, Arvind K

    2016-09-01

    Bacterial degradation of crude oil in response to nutrient treatments has been vastly studied. But there is a paucity of information on kinetic parameters of crude oil degradation. Here we report the nutrient stimulated kinetic parameters of crude oil degradation assessed in terms of CO2 production and oil removal by Pseudomonas aeruginosa AKS1 and Bacillus sp. AKS2. The hydrocarbon degradation rate of P. aeruginosa AKS1 in oil only amended sediment was 10.75 ± 0.65 μg CO2-C g(-1) sediment day(-1) which was similar to degradation rate in sediments with no oil. In presence of both inorganic N & P, the degradation rate increased to 47.22 ± 1.32 μg CO2-C g(-1) sediment day(-1). The half-saturation constant (Ks) and maximum degradation rate (Vmax) for P. aeruginosa AKS1 under increasing N and saturating P concentration were 13.57 ± 0.53 μg N g(-1) sediment and 39.36 ± 1.42 μg CO2-C g(-1) sediment day(-1) respectively. The corresponding values at increasing P and a constant N concentration were 1.60 ± 0.13 μg P g(-1) sediment and 43.90 ± 1.03 μg CO2-C g(-1) sediment day(-1) respectively. Similarly the degradation rate of Bacillus sp. AKS2 in sediments amended with both inorganic nutrients N & P was seven fold higher than the rates in oil only or nutrient only treated sediments. The Ks and Vmax estimates of Bacillus sp. AKS2 under increasing N and saturating P concentration were 9.96 ± 1.25 μg N g(-1) sediment and 59.96 ± 7.56 μg CO2-C g(-1) sediment day(-1) respectively. The corresponding values for P at saturating N concentration were 0.46 ± 0.24 μg P g(-1) sediment and 63.63 ± 3.54 μg CO2-C g(-1) sediment day(-1) respectively. The rates of CO2 production by both isolates were further stimulated when oil concentration was increased above 12.5 mg g(-1) sediment. However, oil degradation activity declined at oil concentration above 40 mg g(-1) sediment when treated with constant nutrient: oil ratio

  4. Pseudomonas aeruginosa quorum-sensing response in the absence of functional LasR and LasI proteins: The case of strain 148, a virulent dolphin isolate.

    PubMed

    Morales, Estefanía; González-Valdez, Abigail; Servín-González, Luis; Soberón-Chávez, Gloria

    2017-06-07

    Pseudomonas aeruginosa is an opportunistic pathogen that presents a complex regulatory network called 'quorum-sensing', which is responsible for the transcription of genes coding for several traits implicated in its pathogenicity. Strain 148 is a dolphin-isolate that has been shown to produce quorum-sensing regulated virulence-traits and to be virulent in a mouse model, despite the fact that it contains a 20 kbp deletion that eliminates from the chromosome the lasR gene and the lasI promoter. LasR is a key quorum-sensing transcriptional regulator that, when coupled with the autoinducer 3-oxo-dodecanoyl homoserine lactone (3O-C12-HSL) produced by LasI, activates transcription of genes coding for some virulence-associated traits such as elastase, lasI, rhlI and rhlR. RhlR is also a key quorum-sensing transcriptional regulator that, when interacting with the autoinducer butanoyl homoserine lactone (C4-HSL) that is produced by the synthase RhlI, activates the genes involved in the synthesis of some virulence-associated traits, as rhamnolipids and pyocyanin. We describe that in P. aeruginosa 148, the LasR/3O-C12-HSL independent rhlR transcriptional-activation is due to the release of the negative effect of Vfr (a CRP-ortholog) caused by the insertion of an IS element in vfr, and that rhlI transcription is driven from the rhlR promoter, forming the rhlR-I operon. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Genetic context and biochemical characterization of the IMP-18 metallo-beta-lactamase identified in a Pseudomonas aeruginosa isolate from the United States.

    PubMed

    Borgianni, Luisa; Prandi, Silvia; Salden, Laurie; Santella, Gisela; Hanson, Nancy D; Rossolini, Gian Maria; Docquier, Jean-Denis

    2011-01-01

    The production of metallo-β-lactamase (MBL) is an important mechanism of resistance to β-lactam antibiotics, including carbapenems. Despite the discovery and emergence of many acquired metallo-β-lactamases, IMP-type determinants (now counting at least 27 variants) remain the most prevalent in some geographical areas. In Asian countries, and notably Japan, IMP-1 and its closely related variants are most widespread. Some other variants have been detected in other countries and show either an endemic (e.g., IMP-13 in Italy) or sporadic (e.g., IMP-12 in Italy or IMP-18 in the United States) occurrence. The IMP-18-producing Pseudomonas aeruginosa strain PS 297 from the southwestern United States carried at least two class 1 integrons. One was identical to In51, while the other, named In133 and carrying the bla(IMP-18) gene cassette in the third position, showed an original array of five gene cassettes, including aacA7, qacF, aadA1, and an unknown open reading frame (ORF). Interestingly. In133 differed significantly from In96, the bla(IMP-18)-carrying integron identified in a P. aeruginosa isolate from Mexico. The meropenem and ertapenem MIC values were much lower for Escherichia coli strains producing IMP-18 (0.06 and 0.12 μg/ml, respectively) than for strains producing IMP-1 (2 μg/ml for each). Kinetic data obtained with the purified enzyme revealed lower turnover rates of IMP-18 than of other IMP-type enzymes with most substrates.

  6. Extracellular biogenic nanomaterials inhibit pyoverdine production in Pseudomonas aeruginosa: a novel insight into impacts of metal(loid)s on environmental bacteria.

    PubMed

    Mohanty, Anee; Liu, Yang; Yang, Liang; Cao, Bin

    2015-02-01

    Anthropogenic activities such as mining, smelting, and industrial use have caused serious problems of metal(loid) pollution in nearly every country in the world. A wide range of environmental microorganisms are capable of transforming metal(loid)s into nanomaterials, i.e., biogenic nanomaterials (bio-NMs), in the environment. Although the impacts of various metal(loid)s on the ecosystems have been extensively studied, the potential influence of the bio-NMs generated in the environment to environmental organisms is largely unexplored. Using tellurium nanomaterials transformed from tellurite by a metal-reducing bacterium as model bio-NMs, we demonstrated that the bio-NMs significantly decreased siderophore production in an environmental bacterium Pseudomonas aeruginosa in both planktonic cultures and biofilms. Transcriptomic analysis revealed that the bio-NMs inhibited the expression of genes involved in biosynthesis and transport of siderophores. Siderophores secreted by certain bacteria in microbial communities can be considered as public goods that can be exploited by local communities, playing an important role in shaping microbial communities. The inhibition of siderophore production by the bio-NMs implies that bio-NMs may have an important influence on the ecosystems through altering specific functions of environmental bacteria. Taken together, this study provides a novel insight into the environmental impacts of metal(loid)s.

  7. Detection of blaSPM-1, blaKPC, blaTEM and blaCTX-M genes in isolates of Pseudomonas aeruginosa, Acinetobacter spp. and Klebsiella spp. from cancer patients with healthcare-associated infections.

    PubMed

    Jácome, Paula Regina Luna de Araújo; Alves, Lílian Rodrigues; Jácome-Júnior, Agenor Tavares; Silva, Maria Jesuíta Bezerra da; Lima, Jailton Lobo da Costa; Araújo, Paulo Sérgio Ramos; Lopes, Ana Catarina S; Maciel, Maria Amélia Vieira

    2016-07-01

    Pseudomonas aeruginosa, Acinetobacter spp. and Klebsiella spp. are three of the pathogens most frequently involved in infections of cancer patients, and the production of β -lactamases is a major mechanism of resistance due to its wide diversity of existing enzymes. Therefore, the aim of the present study was to investigate the microbiological profile and data related to patients and infections, and to search for β -lactamase genes in bacterial isolates from hospitalized cancer patients in a hospital in Recife, Pernambuco, Brazil. A total of 169 isolates were recovered between 2012 and 2014, of which 58 were P. aeruginosa, 36 were Acinetobacter spp. and 75 were Klebsiella spp. A high percentage of carbapenem resistance was observed in P. aeruginosa and Acinetobacter spp. Among the carbapenem-resistant bacteria, the blaSPM-1 gene was detected in P. aeruginosa (35.5 %) and Acinetobacter spp. (3.8 %), while blaKPC was detected in P. aeruginosa (25.8 %) only. Among the third- and fourth-generation cephalosporin-resistant strains, in Klebsiella spp. we detected the genes blaTEM (30.6 %), blaCTX-M (58.3 %) and blaKPC (5.6 %), and in Acinetobacter spp. only blaTEM (25.9 %). This the first report of an Acinetobacter baumannii blaSPM-1 gene carrier that has been isolated in Brazil. The most frequent cancer types were bowel tumour [14.8 %; 95 % confidence interval (CI95 %) 9.8-21.1 %], breast cancer (13.6 %; CI95 % 8.8-19.7 %) and prostate cancer (11.2%; CI95 % 6.9-17.0 %). These results therefore provide knowledge of susceptibility profile and resistance mechanisms and thus can contribute to the strategic formulation of hospital infection control plans and the rational use of antimicrobials, reducing mortality from infection levels in cancer patients.

  8. Final environmental impact statement. Waste Isolation Pilot Plant

    SciTech Connect

    Not Available

    1980-10-01

    This volume contains the appendices for the Final Environmental Impact Statement for the Waste Isolation Pilot Plant (WIPP). Alternative geologic environs are considered. Salt, crystalline rock, argillaceous rock, and tuff are discussed. Studies on alternate geologic regions for the siting of WIPP are reviewed. President Carter's message to Congress on the management of radioactive wastes and the findings and recommendations of the interagency review group on nuclear waste management are included. Selection criteria for the WIPP site including geologic, hydrologic, tectonic, physicochemical compatability, and socio-economic factors are presented. A description of the waste types and the waste processing procedures are given. Methods used to calculate radiation doses from radionuclide releases during operation are presented. A complete description of the Los Medanos site, including archaeological and historic aspects is included. Environmental monitoring programs and long-term safety analysis program are described. (DMC)

  9. Isolation and characterization of novel strains of Pseudomonas aeruginosa and Serratia marcescens possessing high efficiency to degrade gasoline, kerosene, diesel oil, and lubricating oil.

    PubMed

    Wongsa, Patcharaporn; Tanaka, Makiko; Ueno, Akio; Hasanuzzaman, Mohammad; Yumoto, Isao; Okuyama, Hidetoshi

    2004-12-01

    Bacteria possessing high capacity to degrade gasoline, kerosene, diesel oil, and lubricating oil were screened from several areas of Hokkaido, Japan. Among isolates, two strains, WatG and HokM, which were identified as new strains of Pseudomonas aeruginosa and Serratia marcescens species, respectively, showed relatively high capacity and wide spectrum to degrade the hydrocarbons in gasoline, kerosene, diesel, and lubricating oil. About 90-95% of excess amount of total diesel oil and kerosene added to mineral salts media as a sole carbon source could be degraded by WatG within 2 and 3 weeks, respectively. The same amount of lubricating oil was 60% degraded within 2 weeks. Strain HokM was more capable than WatG in degrading aromatic compounds in gasoline. This strain could also degrade kerosene, diesel, and lubricating oil with a capacity of 50-60%. Thus, these two isolates have potential to be useful for bioremediation of sites highly contaminated with petroleum hydrocarbons.

  10. Quinoline-degrading strain Pseudomonas aeruginosa KDQ4 isolated from coking activated sludge is capable of the simultaneous removal of phenol in a dual substrate system.

    PubMed

    Zhang, Panhong; Jia, Rong; Zhang, Yuxiu; Shi, Peili; Chai, Tuanyao

    2016-11-09

    Quinoline is a refractory organic compound in the treatment of coking wastewater. The isolation of high efficiency quinoline-degrading bacteria from activated sludge and the evaluation of their degradation characteristics in the presence of phenol or in the actual coking wastewater are important for the improvement of effluent quality. The novel bacterial strain Pseudomonas aeruginosa KDQ4 was isolated from a quinoline enrichment culture obtained from the activated sludge of a coking wastewater treatment plant. The optimum temperature and initial pH for quinoline degradation were 33-38°C and 8-9, respectively. KDQ4 completely degraded 400 mg/L of quinoline within 24 h and 800 mg/L of phenol within 30 h. In the dual-substrate system, the removal efficiencies of quinoline and phenol at the same initial concentration (200 mg/L) by KDQ4 were 89% and 100% within 24 h, respectively, indicating that KDQ4 could simultaneously and quickly degrade quinoline and phenol in a coexistence system. Moreover, KDQ4 was able to adapt to actual coking wastewater containing high quinoline and phenol concentrations and rapidly remove them. KDQ4 also exhibited heterotrophic nitrification and aerobic denitrification potential under aerobic conditions. These results suggested a potential bioaugmentation role for KDQ4 in the removal of nitrogen-heterocyclic compounds and phenolics from coking wastewater.

  11. Waste Isolation Pilot Plant Biennial Environmental Compliance Report

    SciTech Connect

    Washington Regulatory and Environmental Services

    2006-10-12

    This Biennial Environmental Compliance Report (BECR) documents compliance with environmental regulations at the Waste Isolation Pilot Plant (WIPP), a facility designed and authorized for the safe disposal of transuranic (TRU) radioactive waste. This BECR covers the reporting period from April 1, 2004, to March 31, 2006. As required by the WIPP Land Withdrawal Act (LWA) (Public Law [Pub. L.] 102-579, as amended by Pub. L. 104-201), the BECR documents United States (U.S.) Department of Energy (DOE) compliance with regulations and permits issued pursuant to the following: (1) Title 40 Code of Federal Regulations (CFR) Part 191, Subpart A, "Environmental Standards for Management and Storage"; (2) Clean Air Act (CAA) (42 United States Code [U.S.C.] §7401, et seq.); (3) Solid Waste Disposal Act (SWDA) (42 U.S.C. §§6901-6992, et seq.); (4) Safe Drinking Water Act (SDWA) (42 U.S.C. §§300f, et seq.); (5) Toxic Substances Control Act (TSCA) (15 U.S.C. §§2601, et seq.); (6) Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) (42 U.S.C. §§9601, et seq.); and all other federal and state of New Mexico laws pertaining to public health and safety or the environment.

  12. Evidence of the Cost of the Production of Microcystins by Microcystis aeruginosa under Differing Light and Nitrate Environmental Conditions

    PubMed Central

    Briand, Enora; Bormans, Myriam; Quiblier, Catherine; Salençon, Marie-José; Humbert, Jean-François

    2012-01-01

    The cyanobacterium Microcystis aeruginosa is known to proliferate in freshwater ecosystems and to produce microcystins. It is now well established that much of the variability of bloom toxicity is due to differences in the relative proportions of microcystin-producing and non-microcystin-producing cells in cyanobacterial populations. In an attempt to elucidate changes in their relative proportions during cyanobacterial blooms, we compared the fitness of the microcystin-producing M. aeruginosa PCC 7806 strain (WT) to that of its non-microcystin-producing mutant (MT). We investigated the effects of two light intensities and of limiting and non-limiting nitrate concentrations on the growth of these strains in monoculture and co-culture experiments. We also monitored various physiological parameters, and microcystin production by the WT strain. In monoculture experiments, no significant difference was found between the growth rates or physiological characteristics of the two strains during the exponential growth phase. In contrast, the MT strain was found to dominate the WT strain in co-culture experiments under favorable growth conditions. Moreover, we also found an increase in the growth rate of the MT strain and in the cellular MC content of the WT strain. Our findings suggest that differences in the fitness of these two strains under optimum growth conditions were attributable to the cost to microcystin-producing cells of producing microcystins, and to the putative existence of cooperation processes involving direct interactions between these strains. PMID:22276137

  13. Mutations in the gyrA and parC genes and in vitro activities of fluoroquinolones in 114 clinical isolates of Pseudomonas aeruginosa derived from urinary tract infections and their rapid detection by denaturing high-performance liquid chromatography.

    PubMed

    Matsumoto, Minori; Shigemura, Katsumi; Shirakawa, Toshiro; Nakano, Yuzo; Miyake, Hideaki; Tanaka, Kazushi; Kinoshita, Shohiro; Arakawa, Soichi; Kawabata, Masato; Fujisawa, Masato

    2012-11-01

    Fluoroquinolone (FQ) resistance in Pseudomonas aeruginosa has spread. The purpose of this study was to investigate the correlation between representative FQ, i.e. levofloxacin (LVX), resistance and mutations in the gyrA and parC genes of P. aeruginosa clinical isolates from the urine of urinary tract infection patients and their rapid detection by denaturing high-performance liquid chromatography (DHPLC). The susceptibility to LVX of 114 clinical isolates was measured and the quinolone resistance-determining regions (QRDRs) in the gyrA and parC genes of these isolates were sequenced. DHPLC was undertaken to correlate the distinctive chromatograms with their DNA mutation patterns. Among 114 isolates tested, 22 isolates (19.3%) were resistant to LVX. Six amino acid mutations were detected (Thr83Ile, Asp87Tyr and Asp87Asn in gyrA and Ser87Leu, Ser87Trp and Glu91Arg in parC), existing alone or in combination. There were 10 kinds of mutation patterns. The presence of two or more kinds of mutation significantly correlated with LVX resistance compared with the wild-type or a single mutation (P<0.0001). DHPLC data identified the number of amino acid mutations with reproducibility distinguishable by peak number and profile of the DHPLC chromatogram. In conclusion, two or more mutations in gyrA and parC were significantly related to LVX resistance in P. aeruginosa. DHPLC facilitated the detection of resistant alleles, providing a rapid (5 min per sample), economical (96 samples per run) and reliable technique for characterising LVX resistance in P. aeruginosa. This rapid detection system could forecast LVX resistance by the DHPLC profile. Copyright © 2012. Published by Elsevier B.V.

  14. Enzymatic Modification of Aminoglycoside Antibiotics: a New 3-N-Acetylating Enzyme from a Pseudomonas aeruginosa Isolate

    PubMed Central

    Biddlecome, S.; Haas, M.; Davies, J.; Miller, G. H.; Rane, D. F.; Daniels, P. J. L.

    1976-01-01

    A new 3-N-aminoglycoside acetyltransferase is described, which possesses a wider substrate range than any such enzyme so far discovered in clinical isolates of antibiotic-resistant bacteria. PMID:820250

  15. Waste Isolation Pilot Plant Biennial Environmental Compliance Report

    SciTech Connect

    Westinghouse TRU Solutions

    2000-12-01

    This Biennial Environmental Compliance Report (BECR) documents environmental regulatory compliance at the Waste Isolation Pilot Plant (WIPP), a facility designed for the safe disposal of transuranic (TRU) radioactive waste, for the reporting period of April 1, 1998, to March 31, 2000. As required by the WIPP Land Withdrawal Act (LWA)(Public Law [Pub. L.] 102-579, and amended by Pub. L. 104-201), the BECR documents U.S. Department of Energy (DOE) Carlsbad Area Office's (hereinafter the ''CAO'') compliance with applicable environmental protection laws and regulations implemented by agencies of the federal government and the state of New Mexico. An issue was identified in the 1998 BECR relating to a potential cross-connection between the fire-water systems and the site domestic water system. While the CAO and its managing and operating contractor (hereinafter the ''MOC'') believe the site was always in compliance with cross-connection control requirements, hardware and procedural upgrades w ere implemented in March 1999 to strengthen its compliance posture. Further discussion of this issue is presented in section 30.2.2 herein. During this reporting period WIPP received two letters and a compliance order alleging violation of certain requirements outlined in section 9(a)(1) of the LWA. With the exception of one item, pending a final decision by the New Mexico Environment Department (NMED), all alleged violations have been resolved without the assessment of fines or penalties. Non-mixed TRU waste shipments began on March 26, 1999. Shipments continued through November 26, 1999, the effective date of the Waste Isolation Pilot Plant Hazardous Waste Facility Permit (NM4890139088-TSDF). No shipments regulated under the Hazardous Waste Facility Permit were received at WIPP during this BECR reporting period.

  16. [Susceptibility of Pseudomonas aeruginosa to antibiotics isolated from patients of intensive care units in France in 1998. Resistant phenotypes to beta-lactams].

    PubMed

    Rio, Y; Pina, P; Jurin, F; Allouch, P; Didion, J; Chardon, H; Chiche, D

    2002-02-01

    Pseudomonas aeruginosa is responsible for nosocomial infections and demonstrates many types of resistance mechanisms to antibiotics. Thus, in vitro susceptibility survey are frequently required. In this study, susceptibility has been assessed on 105 non redundant consecutive strains isolated from ICU's in 18 general hospitals, from 01.02.98 to 30.06.98. Only clinically significant samples have been considered. MICs have been measured for nine beta-lactams, three aminoglycosides, one fluoroquinolone and colistine. For ticarcilline resistant strains, phenotype has been assessed on Mueller-Hinton medium supplemented with beta-lactamases inhibitor. Transferable beta-lactamases has been identified using pl and PCR. MIC 50 and MIC 90 (mg/L) for beta-lactams are the following (MIC 50-->90): ticarcilline (16-->512), ticarcilline + clavulanic acid (16-->512), piperacilline (4-->512), pipéracilline + tazobactam (4-->64), aztreonam (4-->16), cefsulodine (4-->32), ceftazidime (2-->16), cefepime (4-->16), imipeneme (1-->8). For aminoglycosides: gentamicine (2-->32), tobramycine (1-->32), amikacine (4-->16). For ciprofloxacine (0.25-->32) and colistine (0.5-->2). According to CA-SFM break points recommendations, 50% of isolated strains are resistant to gentamicine, one out of three for ticarcilline + clavulanic acid (29%), one out of four for tobramycine (25%) and ciprofloxacine (25%), one out of ten for amikacine (9%), tazocilline (8%) and imipeneme (9%). Resistance to ceftazidime and aztreonam is uncommon (respectively 2%-1%) and never observed for cefepim. For ticarcilline resistant strains, (38% of total isolates) the following phenotypes have been detected: 6.7% non enzymatic resistance, 15.2% transferable beta-lactamase (TEM 4.8%, CARB 4.8%, TEM + CARB 4.8% and OXA-10 and derivated 0.9%) and 16.2% high level cephalosporinase. Extended-spectrum beta-lactamase has never been detected. TEM beta-lactamase is associated with resistance to amikacine and ciprofloxacine.

  17. [Determination of associated antimicrobial resistance in clinical isolates of Staphylococcus aureus and Pseudomonas aeruginosa in a public hospital in Goiânia, State of Goiás].

    PubMed

    Kobayashi, Cláudia Castelo Branco Artiaga; Sadoyama, Geraldo; Vieira, José Daniel Gonçalves

    2009-01-01

    This study evaluated the associated antimicrobial resistance of Pseudomonas aeruginosa and Staphylococcus aureus in relation to an antimicrobial agent with other drugs. The associated antimicrobial resistance was calculated by means of the relative risk. There was an obvious relationship between oxacillin resistance and resistance to other antimicrobial agents among isolates of oxacillin-resistant Staphylococcus aureus (68.5%), greater than 32%, except for linezolid (6.7%). Pronounced associated resistance among drugs was observed for Pseudomonas aeruginosa isolates, particularly for ciprofloxacin and carbapenems (59.6% to 60.7%) and for aminoglycosides and carbapenems (66.3 % to 67.7 %) and other beta-lactam antibiotics (52.3% to 85.8%). The present study emphasizes the importance of diagnostic cultures and susceptibility testing for selecting the correct antimicrobial agent, with regard to the clinical impact of increased multiresistance and selection of associated antimicrobial resistance.

  18. Characterization and survival of environmental Escherichia coli O26 isolates in ground beef and environmental samples.

    PubMed

    Palmer, Christine E; Bratcher, Christy L; Singh, Manpreet; Wang, Luxin

    2015-04-01

    In addition to Escherichia coli O157:H7, shiga toxin-producing E. coli (STEC) O26 was added to the zero-tolerance adulterant list together with other 5 non-O157 STEC serogroups in 2012. Four farm O26 isolates were used in this study; they were obtained from a on-farm survey study conducted in Alabama. The presence of 3 major pathogenic genes (stx1, stx2, and eaeA) was determined through multiplex polymerase chain reaction (PCR). Two major pathogenic gene profiles were observed: 3 of the farm isolates contain only the eaeA gene whereas 1 farm isolate has both the eaeA and the stx1 genes. No significant difference was seen among the 4 farm isolates in the antibiotic resistance tests. To test their survival in ground beef and environmental samples, 2 inoculums were prepared and inoculated at various concentrations into samples of ground beef, bovine feces, bedding materials, and trough water. One inoculum was made of 3 farm isolates containing only the eaeA gene and another inoculum contained the isolate with both the eaeA and stx1 genes. Inoculated beef samples were stored at 4 °C for 10 d and the inoculated environmental samples were stored at ambient temperature for 30 d. Results showed that virulence gene profiles do not have an impact on O26's ability to survive in ground beef and in environment (P > 0.05). The inoculation levels, sample types as well as the storage times are the major factors that impact O26 survival (P < 0.05).

  19. [Environmental fitness of metalaxyl-resistant isolate of Phytophthora capsici].

    PubMed

    Wang, Guangfei; Ma, Yan

    2015-05-04

    The environmental fitness of metalaxyl-resistant isolate of Phytophthora capsici was studied for assessing the risk of metalaxyl-resistant P. capsici. We studied the main biological characteristics, competitive ability on plate, pathogenicity on pepper plant and adaptability in soil of the laboratory-induced metalaxyl-resistant isolate of P. capsici (Pc2-3 strain), with the metalaxyl-sensitive isolate (Pc2 strain, the wild-type) as the control. The zoosporangia production, releasing rate of zoosporangia and germination rate of zoospores of Pc2-3 were less than that of Pc2. The temperature range, optimum temperature range and initial pH range for mycelia growth of Pc2-3 were consistent with that of Pc2, but mycelia growth rate of Pc2-3 was lower than that of Pc2. Pc2-3 exhibited significantly weak competitive ability compared with Pc2 on carrots plate. Disease incidence of pepper inoculated with Pc2-3 (14.3%) was significantly lower than that of Pc2 (88. 6% ). When pepper plant was inoculated by mixtures of zoospore suspension of Pc2-3 and Pc2 at same ratio, the disease incidence, closing to that by Pc2 strain, was 75.7% . And all the strains isolated from diseased plants in the treatment were metalaxyl-sensitive. The density of P. capsis Pc2-3 was 0.28 times of Pc2 after the soil inoculated with Pc2-3 and Pc2 respectively at same zoospores density was incubated for 20 days. Otherwise, the ratio of Pc2-3 to Pc2 was 0.42 if the metalaxyl concentration in the soil was 300 mg/kg dry soil. No matter the soil temperature and humidity were beneficial to survival of P. capsici or not, Pc2-3 showed lower soil adaptability than Pc2. The environmental fitness of metalaxyl-resistant P. capsis Pc2-3 was weaker than the metalaxyl- sensitive strain Pc2 (the wild-type).

  20. Final environmental impact statement. Waste Isolation Pilot Plant

    SciTech Connect

    Not Available

    1980-10-01

    In accordance with the National Environmental Policy Act (NEPA) of 1969, the US Department of Energy (DOE) has prepared this document as environmental input to future decisions regarding the Waste Isolation Pilot Plant (WIPP), which would include the disposal of transuranic waste, as currently authorized. The alternatives covered in this document are the following: (1) Continue storing transuranic (TRU) waste at the Idaho National Engineering Laboratory (INEL) as it is now or with improved confinement. (2) Proceed with WIPP at the Los Medanos site in southeastern New Mexico, as currently authorized. (3) Dispose of TRU waste in the first available repository for high-level waste. The Los Medanos site would be investigated for its potential suitability as a candidate site. This is administration policy and is the alternative preferred by the DOE. (4) Delay the WIPP to allow other candidate sites to be evaluated for TRU-waste disposal. This environmental impact statement is arranged in the following manner: Chapter 1 is an overall summary of the analysis contained in the document. Chapters 2 and 4 set forth the objectives of the national waste-management program and analyze the full spectrum of reasonable alternatives for meeting these objectives, including the WIPP. Chapter 5 presents the interim waste-acceptance criteria and waste-form alternatives for the WIPP. Chapters 6 through 13 provide a detailed description and environmental analysis of the WIPP repository and its site. Chapter 14 describes the permits and approvals necessary for the WIPP and the interactions that have taken place with Federal, State, and local authorities, and with the general public in connection with the repository. Chapter 15 analyzes the many comments received on the DEIS and tells what has been done in this FEIS in response. The appendices contain data and discussions in support of the material in the text.

  1. Pseudomonas aeruginosa Biofilm Formation and Persistence, along with the Production of Quorum Sensing-Dependent Virulence Factors, Are Disrupted by a Triterpenoid Coumarate Ester Isolated from Dalbergia trichocarpa, a Tropical Legume

    PubMed Central

    Pottier, Laurent; Huet, Joelle; Rabemanantsoa, Christian; Kiendrebeogo, Martin; Andriantsimahavandy, Abel; Rasamindrakotroka, Andry; Stévigny, Caroline; Duez, Pierre; El Jaziri, Mondher

    2015-01-01

    Recently, extracts of Dalbergia trichocarpa bark have been shown to disrupt P. aeruginosa PAO1 quorum sensing (QS) mechanisms, which are key regulators of virulence factor expression and implicated in biofilm formation. One of the active compounds has been isolated and identified as oleanolic aldehyde coumarate (OALC), a novel bioactive compound that inhibits the formation of P. aeruginosa PAO1 biofilm and its maintenance as well as the expression of the las and rhl QS systems. Consequently, the production of QS-controlled virulence factors including, rhamnolipids, pyocyanin, elastase and extracellular polysaccharides as well as twitching and swarming motilities is reduced. Native acylhomoserine lactones (AHLs) production is inhibited by OALC but exogenous supply of AHLs does not restore the production of virulence factors by OALC-treated cultures, indicating that OALC exerts its effect beyond AHLs synthesis in the QS pathways. Further experiments provided a significant inhibition of the global virulence factor activator gacA by OALC. OALC disorganizes established biofilm structure and improves the bactericidal activity of tobramycin against biofilm-encapsulated PAO1 cells. Finally, a significant reduction of Caenorhabditis elegans paralysis was recorded when the worms were infected with OALC-pre-treated P. aeruginosa. Taken together, these results show that triterpenoid coumarate esters are suitable chemical backbones to target P. aeruginosa virulence mechanisms. PMID:26186595

  2. Pseudomonas aeruginosa Biofilm Formation and Persistence, along with the Production of Quorum Sensing-Dependent Virulence Factors, Are Disrupted by a Triterpenoid Coumarate Ester Isolated from Dalbergia trichocarpa, a Tropical Legume.

    PubMed

    Rasamiravaka, Tsiry; Vandeputte, Olivier M; Pottier, Laurent; Huet, Joelle; Rabemanantsoa, Christian; Kiendrebeogo, Martin; Andriantsimahavandy, Abel; Rasamindrakotroka, Andry; Stévigny, Caroline; Duez, Pierre; El Jaziri, Mondher

    2015-01-01

    Recently, extracts of Dalbergia trichocarpa bark have been shown to disrupt P. aeruginosa PAO1 quorum sensing (QS) mechanisms, which are key regulators of virulence factor expression and implicated in biofilm formation. One of the active compounds has been isolated and identified as oleanolic aldehyde coumarate (OALC), a novel bioactive compound that inhibits the formation of P. aeruginosa PAO1 biofilm and its maintenance as well as the expression of the las and rhl QS systems. Consequently, the production of QS-controlled virulence factors including, rhamnolipids, pyocyanin, elastase and extracellular polysaccharides as well as twitching and swarming motilities is reduced. Native acylhomoserine lactones (AHLs) production is inhibited by OALC but exogenous supply of AHLs does not restore the production of virulence factors by OALC-treated cultures, indicating that OALC exerts its effect beyond AHLs synthesis in the QS pathways. Further experiments provided a significant inhibition of the global virulence factor activator gacA by OALC. OALC disorganizes established biofilm structure and improves the bactericidal activity of tobramycin against biofilm-encapsulated PAO1 cells. Finally, a significant reduction of Caenorhabditis elegans paralysis was recorded when the worms were infected with OALC-pre-treated P. aeruginosa. Taken together, these results show that triterpenoid coumarate esters are suitable chemical backbones to target P. aeruginosa virulence mechanisms.

  3. Differences in antimicrobial susceptibility breakpoints for Pseudomonas aeruginosa, isolated from blood cultures, set by the Clinical and Laboratory Standards Institute (CLSI) and the Japanese Society of Chemotherapy.

    PubMed

    Nakamura, Tatsuya; Shimizu, Chihiro; Kasahara, Mayumi; Nakata, Chiyo; Munakata, Machiko; Takahashi, Hakuo

    2007-02-01

    A study was made of the antimicrobial susceptibility to and efficacy of various kinds of antimicrobial agents against 179 strains of Pseudomonas aeruginosa that were isolated from blood cultures at Kansai Medical University Hospital from 1990 through 2004. The annual detection rate was highest in 1994, at 22 strains (6.5%). There were 9 multidrug resistant strains of Pseudomonas aeruginosa (5.0%). Among 14 antimicrobial agents tested for measurements, ciprofloxacin (CPFX) showed the best minimum inhibitory concentration (MIC) 50 value, of 0.25 microg/ml, followed by pazufloxacin (PZFX) and biapenem (BIPM), each at 0.5 microg/ml. When the period of 15 years was divided into three stages, the MIC50 value for each antimicrobial agent was highest in the middle stage (1995 to 1999). Assuming that the percentage of sensitive strains according to the breakpoints set by the Clinical and Laboratory Standards Institute (CLSI) represents the antimicrobial susceptibility rate, amikacin (AMK) showed the best value, of 85.5%. According to the sepsis breakpoint set by the Japanese Society of Chemotherapy (JSC), the efficacy of CPFX showed the highest rate (77.1%) of all the antimicrobial agents tested. Among beta-lactams, BIPM showed the highest efficacy rate, of 67.0%. When the efficacy rates were compared with each other, the difference in efficacy rate between the breakpoint set by the CLSI and the sepsis breakpoint set by the JSC was large for beta-lactams. Comparisons made based on the CLSI criteria showed no difference in cross-resistance rates between CPFX, meropenem (MEPM), and BIPM. However, when comparisons were made using the JSC sepsis breakpoint, MEPM showed a cross-resistance rate of 87.8%, while the rate for BIPM was lower, at 56.1%, with the chi2 test showing a significant difference, at P = 0.0014. In accordance with the pharmacokinetics/pharmacodynamics theory that has been advocated, breakpoints which are more suitable for the clinical setting in Japan should

  4. New genotyping method discovers sustained nosocomial Pseudomonas aeruginosa outbreak in an intensive care burn unit.

    PubMed

    Tissot, F; Blanc, D S; Basset, P; Zanetti, G; Berger, M M; Que, Y-A; Eggimann, P; Senn, L

    2016-09-01

    Pseudomonas aeruginosa is a leading cause of healthcare-associated infections in the intensive care unit (ICU). To investigate an unexplained increase in the incidence of P. aeruginosa recovered from clinical samples in the ICU over a two-year period. After unsuccessful epidemiological investigation by conventional tools, P. aeruginosa clinical isolates of all patients hospitalized between January 2010 and July 2012 were typed by a novel double-locus sequence typing (DLST) method and compared to environmental isolates recovered during the investigation period. In total, 509 clinical isolates from 218 patients and 91 environmental isolates were typed. Thirty-five different genotypic clusters were found in 154 out of 218 patients (71%). The largest cluster, DLST 1-18, included 23 patients who were mostly hospitalized during overlapping periods in the burn unit. Genotype DLST 1-18 was also recovered from floor traps, shower trolleys and the shower mattress in the hydrotherapy rooms, suggesting environmental contamination of the burn unit as the source of the outbreak. After implementation of appropriate infection control measures, this genotype was recovered only once in a clinical sample from a burned patient and twice in the environment, but never thereafter during a 12-month follow-up period. The use of a novel DLST method allowed the genotyping of a large number of clinical and environmental isolates, leading to the identification of the environmental source of a large unrecognized outbreak in the burn unit. Eradication of the outbreak was confirmed after implementation of a continuous epidemiological surveillance of P. aeruginosa clones in the ICU. Copyright © 2016 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  5. Waste Isolation Pilot Plant Biennial Environmental Compliance Report

    SciTech Connect

    Washinton TRU Solutions LLC

    2002-09-30

    This Biennial Environmental Compliance Report (BECR) documents environmental regulatory compliance at the Waste Isolation Pilot Plant (WIPP), a facility designed for the safe disposal of transuranic (TRU) radioactive waste, for the reporting period of April 1, 2000, to March 31, 2002. As required by the WIPP Land Withdrawal Act (LWA)(Public Law [Pub. L.] 102-579, as amended by Pub. L. 104-201), the BECR documents U.S. Department of Energy (DOE) Carlsbad Field Office's (CBFO) compliance with applicable environmental protection laws and regulations implemented by agencies of the federal government and the state of New Mexico. In the prior BECR, the CBFO and the management and operating contractor (MOC)committed to discuss resolution of a Letter of Violation that had been issued by the New Mexico Environment Department (NMED) in August 1999, which was during the previous BECR reporting period. This Letter of Violation alleged noncompliance with hazardous waste aisle spacing, labeling, a nd tank requirements. At the time of publication of the prior BECR, resolution of the Letter of Violation was pending. On July 7, 2000, the NMED issued a letter noting that the aisle spacing and labeling concerns had been adequately addressed and that they were rescinding the violation alleging that the Exhaust Shaft Catch Basin failed to comply with the requirements for a hazardous waste tank. During the current reporting period, WIPP received a Notice of Violation and a compliance order alleging the violation of the New Mexico Hazardous Waste Regulations and the WIPP Hazardous Waste Facility Permit (HWFP).

  6. O serotype-independent susceptibility of Pseudomonas aeruginosa to lectin-like pyocins

    PubMed Central

    Ghequire, Maarten G K; Dingemans, Jozef; Pirnay, Jean-Paul; De Vos, Daniel; Cornelis, Pierre; De Mot, René

    2014-01-01

    Lectin-like bacteriocins of the LlpA family, originally identified in plant-associated bacteria, are narrow-s