First Survey of Metallo-β-Lactamase Producers in Clinical Isolates of Pseudomonas aeruginosa From a Referral Burn Center in Kurdistan Province.

PubMed

Kalantar, Enayatollah; Torabi, Vahideh; Salimizand, Heiman; Soheili, Fariborz; Beiranvand, Soheila; Soltan Dallal, Mohammad Mehdi

2012-01-01

Treatment of infectious diseases is becoming more challenging with each passing year. This is especially true for infections caused by Pseudomonas aeruginosa, an opportunistic pathogen with the ability to rapidly develop resistance to multiple classes of antibiotics. This study was conducted to determine the prevalence of metallo-β-lactamase (MBL)-producing strains among multidrug-resistant P. aeruginosa strains isolated from burn patients. The isolates were identified, tested for susceptibility to various antimicrobial agents, and screened for the presence of MβLs by using the double-disk synergy test. The minimal inhibitory concentration of imipenem was determined by microplate broth dilution method on Mueller-Hinton agar. To detect VIM, SIM, and GIM MBLs, the isolates were subjected to polymerase chain reaction. In this study, we identified 100 P. aeruginosa isolates from 176 clinical specimens obtained from burn patients. The isolates showed maximum resistance to ampicillin (100%), ceftazidime (94%), and ceftriaxone (89%). The CLSI-MBL phenotypic test showed that of the 100 P. aeruginosa isolates, 22 (22%) were positive for MBL production in the double-disk synergy test. Of the 22 MBL-positive P. aeruginosa isolates, 8 were resistant to imipenem. PCR analysis showed that 8 isolates were positive for blaVIM1. The other genes blaSIM1 and blaGIM1 were not detected. The study results demonstrate the serious therapeutic threat of the spread of MBL producers among P. aeruginosa populations. Metallo-β-lactamases were detected in 22% of imipenem-resistant P. aeruginosa isolates. Early detection and infection-control practices are the best antimicrobial strategies for this organism; therefore, systematic surveillance to detect MBL producers is necessary.

Identification and characterization of metallo-β-lactamases producing Pseudomonas aeruginosa clinical isolates in University Hospital from Zanjan Province, Iran.

PubMed

Doosti, Masoumeh; Ramazani, Ali; Garshasbi, Maryam

2013-01-01

Infectious by Pseudomonas aeruginosa has spread worldwide and metallo-beta-lactamases (MBL) are being reported with increasing frequency. The aim of this study was to investigate the antibiotic susceptibility and distribution of blaVIM and blaIMP genes in P. aeruginosa isolates from Zanjan Province of Iran. A total of 70 P. aeruginosa isolates were identified from patients admitted at intensive care units. The antimicrobial susceptibility was tested by disk diffusion (Kirby-Bauer) method and for production of MBL using double-disk synergy test (DDST). After DNA extraction, the presence of blaVIM and blaIMP genes and class 1 integron were detected by PCR. Most of the isolates were resistant to meropenem, cefotaxime and imipenem (IPM). Also, 44/70 (62.85%) IPM resistant isolates were confirmed by DDST. Of the 44 clinical isolates, 41 (93%) isolates showed MIC≥4 µg/ml for IPM. Based on the DDST results, 36 (87.8%) were confirmed to be MBL producers. PCR amplification showed that 23/41 (56%) carried blaVIM and 10/41 (24.3%) possessed blaIMP gene. Also, 31/44 (70.5%) isolates contained class 1 integron gene. Our results highlight that the genes for Verona integron-encoded metallo-β-lactamase, IPM β-lactamases and class 1 integrons were predominantly present among the IPM-resistant P. aeruginosa tested in our province and also the frequency of blaVIM type is higher than blaIMP. This is the first report of P. aeruginosa strains producing blaIMP with high frequency from Zanjan province of Iran.

Isolation of Shiga toxin-producing Escherichia coli from fresh produce using STEC heart infusion washed blood agar with mitomycin-C.

PubMed

Lin, Andrew; Nguyen, Lam; Clotilde, Laurie M; Kase, Julie A; Son, Insook; Lauzon, Carol R

2012-11-01

The ability to detect and isolate Shiga toxin-producing Escherichia coli (STEC) remains a major challenge for food microbiologists. Although methods based on nucleic acids and antibodies have improved detection of STECs in foods, isolation of these bacteria remains arduous. STEC isolation is necessary for matching food, environmental, and clinical isolates during outbreak investigations and for distinguishing between pathogenic and nonpathogenic organisms. STEC heart infusion washed blood agar with mitomycin-C (SHIBAM) is a modification of washed sheep blood agar prepared by adding mitomycin-C and optimizing both the washed blood and base agar to better isolate STECs. Most STEC isolates produce a zone of hemolysis on SHIBAM plates and are easily distinguishable from background microbiota. Here, we present data supporting the use of SHIBAM to isolate STECs from fresh produce. SHIBAM was tested for accuracy in identifying STECs (365 of 410 STEC strains were hemolytic, and 63 of 73 E. coli strains that did not produce Shiga toxin were not hemolytic) and for recovery from artificially inoculated fresh produce (11 of 24 romaine lettuce samples and 6 of 24 tomato samples). STEC recovery with SHIBAM agar was greatly improved when compared with recovery on Levine's eosin-methylene blue agar as a reference method.

[Metallo-beta-lactamase-mediated resistance among carbapenem-resistant Pseudomonas aeruginosa clinical isolates].

PubMed

Mereuţă, Ana Irina; Tuchiluş, Cristina; Bădescu, Aida Corina; Iancu, Luminiţa Smaranda

2011-01-01

The aim of our study was to evaluate the antimicrobial susceptibility profile and the presence of metallo-beta-lactamases (MBLs) among carbapenem-resistant Pseudomonas aeruginosa clinical isolates. A total of 84 P. aeruginosa clinical isolates collected between January 2007- February 2011 from four university hospitals in Iasi (North-East region of Romania) were randomly selected. Antimicrobial susceptibility testing was performed according to CLSI 2010 (Clinical and Laboratory Standards Institute) guidelines. The isolates were tested for MBLs using EPI (EDTA-phenanthroline-imipenem) phenotypic test and polymerase chain reaction (PCR) for bla(VIM) and bla(IMP). Fifty-eight carbapenem resistant strains were identified, from which 24 (41,3%) were positive for VIM-type MBLs. No IMP - type MBL was detected. All MBL-producing isolates displayed a MDR (multidrug resistant) phenotype, two of them were XDR (extensively drug-resistant). Colistin remained the most effective antibiotic. The high proportion of MBL producing P. aeruginosa clinical isolates urges the need for a better use of antibiotics and for efficient infection control measures to prevent dissemination of MBL producers. This is the first report of VIM-like enzymes in P. aeruginosa isolates from the Iasi area.

Antifungal activity of the lipopeptides produced by Bacillus amyloliquefaciens anti-CA against Candida albicans isolated from clinic.

PubMed

Song, Bo; Rong, Yan-Jun; Zhao, Ming-Xin; Chi, Zhen-Ming

2013-08-01

The bacterium Bacillus amyloliquefaciens anti-CA isolated from mangrove system was found to be able to actively kill Candida albicans isolated from clinic. The bacterial strain anti-CA could produce high level of bioactive substance, amylase and protease in the cheap medium containing 2.0 % soybean meal, 2.0 % wheat flour, pH 6.5 within 26 h. After purification, the main bioactive substance was confirmed to be a cyclic lipopeptide containing a heptapeptide, L-Asp→L-Leu→L-Leu→L-Val→L-Val→L-Glu→L-Leu and a 3-OH fatty acid (15 carbons). In addition to C. albicans, the purified lipopeptide can also kill many yeast strains including Metschnikowia bicuspidata, Candida tropicalis, Yarrowia lipolytica and Saccharomyces cerevisiae. After treated by the purified lipopeptide, both the whole cells and protoplasts of C. albicans were destroyed.

Prevalence of Clinically Isolated Metallo-beta-lactamase-producing Pseudomonas aeruginosa, Coding Genes, and Possible Risk Factors in Iran

PubMed Central

Ghasemian, Abdolmajid; Salimian Rizi, Kobra; Rajabi Vardanjani, Hassan; Nojoomi, Farshad

2018-01-01

Background & Objective: The spread of carbapenem-resistant Pseudomonas aeruginosa is a global concern. Metallo-beta-lactamase (MBL) enzymes cause extensive drug resistance among Gram-negative bacteria. The current study aimed at determining the prevalence of MBL-producing P. aeruginosa in Iran. Data extraction: A total of 43 studies were found out of which 36 were adopted. Data were collected from Google, Google Scholar, Science Direct, PubMed, Scopus, Embase, and Sciverse. The terms “Pseudomonas aeruginosa”, “metallo-beta-lactamase”, “prevalence”, “carbapenems”, and “Iran” were searched. Data from the isolates not producing MBLs were excluded from the study. Data were analyzed with Graph Pad Prism 6, meta-analysis section. Results: According to the results of the current study, 36 surveys indicated that 55% of the clinically isolated P. aeruginosa in Iran were resistant to imipenem and meropenem, among which 37.72% were the MBL producers. Among genes encoding MBLs, blaVIM and blaIMP were predominant with the prevalence of 12.91%±11.01% and 12.50%±23.56%, respectively. No report of harboring blaNDM1 and blaSPM1 by P. aeruginosa was found, similar to most of the other countries in Asia. The prevalence of blaVIM and blaIMP from burn settings were 11.50%±3.5% and 24.65%±23%, respectively. Furthermore, the prevalence of these genes was not significantly different among burn and non-burn isolates (P=0.942 and P=0.597, respectively). Moreover, no relationship was observed between the MBL production and patients’ age range. Conclusion: Approximately half of P. aeruginosa isolates were carbapenem-resistant in Iran, and approximately half were the MBL producers. The blaVIM and blaIMP were the predominant MBLs among P. aeruginosa strains, while other genes were not found in P. aeruginosa. Moreover, there was no significant difference between blaVIM and blaIMP among burn and non-burn isolates. Due to the multiple drug resistance conferred by MBLs

Occurrence of the Plasmid-Mediated Fluoroquinolone Resistance qepA1 Gene in Two Clonal Clinical Isolates of CTX-M-15-Producing Escherichia coli from Algeria.

PubMed

Yanat, Betitera; Dali Yahia, Radia; Yazi, Leila; Machuca, Jesús; Díaz-De-Alba, Paula; Touati, Abdelaziz; Pascual, Álvaro; Rodríguez-Martínez, José-Manuel

2017-06-01

QepA is a plasmid-mediated quinolone resistance determinant of low prevalence described worldwide, mainly in Enterobacteriaceae. This study describes, for the first time in Algeria, two clonally related, QepA-producing Escherichia coli clinical isolates positive for CTX-M-15. The clonal spread of these multidrug-resistant isolates is a major public health concern.

First Survey of Metallo-β–Lactamase Producers in Clinical Isolates of Pseudomonas aeruginosa From a Referral Burn Center in Kurdistan Province

PubMed Central

Kalantar, Enayatollah; Torabi, Vahideh; Salimizand, Heiman; Soheili, Fariborz; Beiranvand, Soheila; Soltan Dallal, Mohammad Mehdi

2012-01-01

Background Treatment of infectious diseases is becoming more challenging with each passing year. This is especially true for infections caused by Pseudomonas aeruginosa, an opportunistic pathogen with the ability to rapidly develop resistance to multiple classes of antibiotics. Objectives This study was conducted to determine the prevalence of metallo-β-lactamase (MBL)–producing strains among multidrug-resistant P. aeruginosa strains isolated from burn patients. Materials and Methods The isolates were identified, tested for susceptibility to various antimicrobial agents, and screened for the presence of MβLs by using the double-disk synergy test. The minimal inhibitory concentration of imipenem was determined by microplate broth dilution method on Mueller-Hinton agar. To detect VIM, SIM, and GIM MBLs, the isolates were subjected to polymerase chain reaction. Results In this study, we identified 100 P. aeruginosa isolates from 176 clinical specimens obtained from burn patients. The isolates showed maximum resistance to ampicillin (100%), ceftazidime (94%), and ceftriaxone (89%). The CLSI-MBL phenotypic test showed that of the 100 P. aeruginosa isolates, 22 (22%) were positive for MBL production in the double-disk synergy test. Of the 22 MBL-positive P. aeruginosa isolates, 8 were resistant to imipenem. PCR analysis showed that 8 isolates were positive for blaVIM1. The other genes blaSIM1 and blaGIM1 were not detected. Conclusions The study results demonstrate the serious therapeutic threat of the spread of MBL producers among P. aeruginosa populations. Metallo-β-lactamases were detected in 22% of imipenem-resistant P. aeruginosa isolates. Early detection and infection-control practices are the best antimicrobial strategies for this organism; therefore, systematic surveillance to detect MBL producers is necessary. PMID:24624147

Glucose & sodium chloride induced biofilm production & ica operon in clinical isolates of staphylococci.

PubMed

Agarwal, Astha; Jain, Amita

2013-01-01

All colonizing and invasive staphylococcal isolates may not produce biofilm but may turn biofilm producers in certain situations due to change in environmental factors. This study was done to test the hypothesis that non biofilm producing clinical staphylococci isolates turn biofilm producers in presence of sodium chloride (isotonic) and high concentration of glucose, irrespective of presence or absence of ica operon. Clinical isolates of 100 invasive, 50 colonizing and 50 commensal staphylococci were tested for biofilm production by microtiter plate method in different culture media (trypticase soy broth alone or supplemented with 0.9% NaCl/ 5 or 10% glucose). All isolates were tested for the presence of ica ADBC genes by PCR. Biofilm production significantly increased in the presence of glucose and saline, most, when both glucose and saline were used together. All the ica positive staphylococcal isolates and some ica negative isolates turned biofilm producer in at least one of the tested culture conditions. Those remained biofilm negative in different culture conditions were all ica negative. The present results showed that the use of glucose or NaCl or combination of both enhanced biofilm producing capacity of staphylococcal isolates irrespective of presence or absence of ica operon.

Structural determination of the polysaccharide isolated from biofilms produced by a clinical strain of Klebsiella pneumoniae.

PubMed

Cescutti, Paola; De Benedetto, Gianluigi; Rizzo, Roberto

2016-07-22

Klebsiella pneumoniae are Gram negative opportunistic pathogens producing capsular (K) polysaccharides. Seventy-seven different K antigens have been described and they are the basis for K serotyping. Capsular polysaccharides are important virulence factors and have a relevant role for the structure of biofilm communities. Nevertheless, little information is available on the polysaccharides produced in biofilm matrices by Klebsiella spp. In the present study, a clinical isolate of Klebsiella pneumoniae was grown both on cellulose membranes deposited on agar plates, where it formed an adherent biofilm, and in liquid medium, where it formed floating biofilms (flocs). Extraction and purification of the polysaccharide fraction showed that only one main carbohydrate polymer was present in both adherent biofilms and flocs. Composition and linkage analysis, Smith degradation followed by ESI-MS, 1D and 2D NMR spectroscopy revealed that the polysaccharide belong to the type K24 and has the following structure. Copyright © 2016 Elsevier Ltd. All rights reserved.

Indistinguishable NDM-producing Escherichia coli isolated from recreational waters, sewage, and a clinical specimen in Ireland, 2016 to 2017

PubMed Central

Mahon, Bláthnaid M; Brehony, Carina; McGrath, Elaine; Killeen, James; Cormican, Martin; Hickey, Paul; Keane, Shane; Hanahoe, Belinda; Dolan, Ann; Morris, Dearbháile

2017-01-01

In this study, New Delhi metallo-beta-lactamase (NDM)-producing Enterobacteriaceae were identified in Irish recreational waters and sewage. Indistinguishable NDM-producing Escherichia coli by pulsed-field gel electrophoresis were isolated from sewage, a fresh water stream and a human source. NDM-producing Klebsiella pneumoniae isolated from sewage and seawater in the same area were closely related to each other and to a human isolate. This raises concerns regarding the potential for sewage discharges to contribute to the spread of carbapenemase-producing Enterobacteriaceae. PMID:28449738

Isolation, genotyping, and antimicrobial resistance of zoonotic shiga toxin-producing escherichia coli

USDA-ARS?s Scientific Manuscript database

Shiga toxin-producing Escherichia coli (STEC) is an enteric pathogen linked to outbreaks of human gastroenteritis with diverse clinical spectra. Traditional culture and isolation methods, including selective enrichment and differential plating, have enabled the effective recovery of STEC. Ruminants ...

Study on biofilm-forming properties of clinical isolates of Staphylococcus aureus.

PubMed

Taj, Yasmeen; Essa, Farhan; Aziz, Faisal; Kazmi, Shahana Urooj

2012-05-14

The purpose of this study was to observe the formation of biofilm, an important virulence factor, by isolates of Staphylococcus aureus (S. aureus) in Pakistan by different conventional methods and through electron microscopy. We screened 115 strains of S. aureus isolated from different clinical specimens by tube method (TM), air-liquid interface coverslip assay method, Congo red agar (CRA) method, and scanning electron microscopy (SEM). Out of 115 S. aureus isolates, 63 (54.78%) showed biofilm formation by tube method. Biofilm forming bacteria were further categorized as high producers (n = 23, 20%) and moderate producers (n = 40, 34.78%). TM coordinated well with the coverslip assay for strong biofilm-producing strains in 19 (16.5%) isolates. By coverslip method, weak producers were difficult to differentiate from biofilm negative isolates. Screening on CRA showed biofilm formation only in four (3.47%) strains. Scanning electron micrographs showed the biofilm-forming strains of S. aureus arranged in a matrix on the propylene surface and correlated well with the TM. Biofilm production is a marker of virulence for clinically relevant staphylococcal infections. It can be studied by various methods but screening on CRA is not recommended for investigation of biofilm formation in Staphylococcus aureus. Electron micrograph images correlate well with the biofilm production as observed by TM.

Clinical and Microbiologic Characteristics of Clostridium difficile Infection Caused by Binary Toxin Producing Strain in Korea.

PubMed

Kim, Jieun; Seo, Mi-Ran; Kang, Jung Oak; Choi, Tae Yeal; Pai, Hyunjoo

2013-06-01

Binary toxin-producing Clostridium difficile infections (CDI) are known to be more severe and to cause higher case fatality rates than those by binary toxin-negative isolates. There has been few data of binary toxin-producing CDI in Korea. Objective of the study is to characterize clinical and microbiological trait of CDI cause by binary-toxin producing isolates in Korea. From September 2008 through January 2010, clinical characteristics, medication history and treatment outcome of all the CDI patients were collected prospectively. Toxin characterization, PCR ribotyping and antibiotic susceptibility were performed with the stool isolates of C. difficile. During the period, CDI caused by 11binary toxin-producing isolates and 105 toxin A & toxin B-positive binary toxin-negative isolates were identified. Comparing the disease severity and clinical findings between two groups, leukocytosis and mucoid stool were more frequently observed in patients with binary toxin-positive isolates (OR: 5.2, 95% CI: 1.1 to 25.4, P = 0.043; OR: 7.6, 95% CI: 1.6 to 35.6, P = 0.010, respectively), but clinical outcome of 2 groups did not show any difference. For the risk factors for acquisition of binary toxin-positive isolates, previous use of glycopeptides was the significant risk factor (OR: 6.2, 95% CI: 1.4 to 28.6, P = 0.019), but use of probiotics worked as an inhibitory factor (OR: 0.1, 95% CI: 0.0 to 0.8; P = 0.026). PCR ribotypes of binary toxinproducing C. difficile showed variable patterns: ribotype 130, 4 isolates; 027, 3 isolates; 267 and 122, 1 each isolate and unidentified C1, 2 isolates. All 11 binary toxin-positive isolates were highly susceptible to clindamycin, moxifloxacin, metronidazole, vancomycin and piperacillin-tazobactam, however, 1 of 11 of the isolates was resistant to rifaximin. Binary toxin-producing C. difficile infection was not common in Korea and those isolates showed diverse PCR ribotypes with high susceptibility to antimicrobial agents. Glycopeptide

Clinical and Microbiologic Characteristics of Clostridium difficile Infection Caused by Binary Toxin Producing Strain in Korea

PubMed Central

Kim, Jieun; Seo, Mi-ran; Kang, Jung Oak; Choi, Tae Yeal

2013-01-01

Background Binary toxin-producing Clostridium difficile infections (CDI) are known to be more severe and to cause higher case fatality rates than those by binary toxin-negative isolates. There has been few data of binary toxin-producing CDI in Korea. Objective of the study is to characterize clinical and microbiological trait of CDI cause by binary-toxin producing isolates in Korea. Materials and Methods From September 2008 through January 2010, clinical characteristics, medication history and treatment outcome of all the CDI patients were collected prospectively. Toxin characterization, PCR ribotyping and antibiotic susceptibility were performed with the stool isolates of C. difficile. Results During the period, CDI caused by 11binary toxin-producing isolates and 105 toxin A & toxin B-positive binary toxin-negative isolates were identified. Comparing the disease severity and clinical findings between two groups, leukocytosis and mucoid stool were more frequently observed in patients with binary toxin-positive isolates (OR: 5.2, 95% CI: 1.1 to 25.4, P = 0.043; OR: 7.6, 95% CI: 1.6 to 35.6, P = 0.010, respectively), but clinical outcome of 2 groups did not show any difference. For the risk factors for acquisition of binary toxin-positive isolates, previous use of glycopeptides was the significant risk factor (OR: 6.2, 95% CI: 1.4 to 28.6, P = 0.019), but use of probiotics worked as an inhibitory factor (OR: 0.1, 95% CI: 0.0 to 0.8; P = 0.026). PCR ribotypes of binary toxinproducing C. difficile showed variable patterns: ribotype 130, 4 isolates; 027, 3 isolates; 267 and 122, 1 each isolate and unidentified C1, 2 isolates. All 11 binary toxin-positive isolates were highly susceptible to clindamycin, moxifloxacin, metronidazole, vancomycin and piperacillin-tazobactam, however, 1 of 11 of the isolates was resistant to rifaximin. Conclusions Binary toxin-producing C. difficile infection was not common in Korea and those isolates showed diverse PCR ribotypes with high

Occurrence of qnr-positive clinical isolates in Klebsiella pneumoniae producing ESBL or AmpC-type beta-lactamase from five pediatric hospitals in China.

PubMed

Wang, Aihua; Yang, Yonghong; Lu, Quan; Wang, Yi; Chen, Yuan; Deng, Li; Ding, Hui; Deng, Qiulian; Wang, Li; Shen, Xuzhuang

2008-06-01

The plasmid-mediated quinolone resistance qnr genes in clinical isolates in adults have been described in different countries; however, the frequency of their occurrence has not been detected in pediatric patients. A total of 410 clinical isolates of Klebsiella pneumoniae, identified as producers of an extended-spectrum beta-lactamase (ESBL), or AmpC beta-lactamase, were collected from five children's hospitals in China during 2005-2006. The isolates were screened for the presence of the qnrA, qnrB, and qnrS genes, and then the harboring qnr gene isolates were detected for a bla gene coding for the TEM, SHV, CTX-M, and plasmid-mediated ampC gene by a PCR experiment. Ninety-two isolates (22.7%) were positive for the qnr gene, including 10 of qnrA (2.4%), 25 of qnrB (6.1%), and 62 of qnrS (15.1%). Eighty-one of the 92 (88.0%) qnr-positive isolates carried at least one bla gene for TEM, SHV, CTX-M, or DHA-1. The ciprofloxacin resistance increased 16-256-fold and oflaxacin resistance increased 2-32-fold in transconjugants, respectively. These results indicated that the plasmid-mediated qnr quinolone resistance gene was qnrS, followed by qnrB and qnrA. Most of the isolates also carried a bla gene coding ESBL or ampC gene coding DHA-1 among Klebsiella pneumoniae isolated from Chinese pediatric patients.

Genetic characterization of Shiga toxin-producing Escherichia coli O26:H11 strains isolated from animal, food, and clinical samples.

PubMed

Krüger, Alejandra; Lucchesi, Paula M A; Sanso, A Mariel; Etcheverría, Analía I; Bustamante, Ana V; Burgán, Julia; Fernández, Luciana; Fernández, Daniel; Leotta, Gerardo; Friedrich, Alexander W; Padola, Nora L; Rossen, John W A

2015-01-01

The Shiga-toxin producing Escherichia coli (STEC) may cause serious illness in human. Here we analyze O26:H11 strains known to be among the most reported STEC strains causing human infections. Genetic characterization of strains isolated from animal, food, and clinical specimens in Argentina showed that most carried either stx 1a or stx 2a subtypes. Interestingly, stx 2a-positive O26:H11 rarely isolated from cattle in other countries showed to be an important proportion of O26:H11 strains circulating in cattle and food in our region. Seventeen percent of the isolates harbored more than one gene associated with antimicrobial resistance. In addition to stx, all strains contained the virulence genes eae-β, tir, efa, iha, espB, cif, espA, espF, espJ, nleA, nleB, nleC, and iss; and all except one contained ehxA, espP, and cba genes. On the other hand, toxB and espI genes were exclusively observed in stx 2-positive isolates, whereas katP was only found in stx 1a-positive isolates. Our results show that O26:H11 STEC strains circulating in Argentina, including those isolated from humans, cattle, and meat products, present a high pathogenic potential, and evidence that cattle can be a reservoir of O26:H11 strains harboring stx 2a.

Genetic characterization of Shiga toxin-producing Escherichia coli O26:H11 strains isolated from animal, food, and clinical samples

PubMed Central

Krüger, Alejandra; Lucchesi, Paula M. A.; Sanso, A. Mariel; Etcheverría, Analía I.; Bustamante, Ana V.; Burgán, Julia; Fernández, Luciana; Fernández, Daniel; Leotta, Gerardo; Friedrich, Alexander W.; Padola, Nora L.; Rossen, John W. A.

2015-01-01

The Shiga-toxin producing Escherichia coli (STEC) may cause serious illness in human. Here we analyze O26:H11 strains known to be among the most reported STEC strains causing human infections. Genetic characterization of strains isolated from animal, food, and clinical specimens in Argentina showed that most carried either stx1a or stx2a subtypes. Interestingly, stx2a-positive O26:H11 rarely isolated from cattle in other countries showed to be an important proportion of O26:H11 strains circulating in cattle and food in our region. Seventeen percent of the isolates harbored more than one gene associated with antimicrobial resistance. In addition to stx, all strains contained the virulence genes eae-β, tir, efa, iha, espB, cif, espA, espF, espJ, nleA, nleB, nleC, and iss; and all except one contained ehxA, espP, and cba genes. On the other hand, toxB and espI genes were exclusively observed in stx2-positive isolates, whereas katP was only found in stx1a-positive isolates. Our results show that O26:H11 STEC strains circulating in Argentina, including those isolated from humans, cattle, and meat products, present a high pathogenic potential, and evidence that cattle can be a reservoir of O26:H11 strains harboring stx2a. PMID:26539413

Biofilm formation, cellulose production, and curli biosynthesis by Salmonella originating from produce, animal, and clinical sources.

PubMed

Solomon, Ethan B; Niemira, Brendan A; Sapers, Gerald M; Annous, Bassam A

2005-05-01

The ability of 71 strains of Salmonella enterica originating from produce, meat, or clinical sources to form biofilms was investigated. A crystal violet binding assay demonstrated no significant differences in biofilm formation by isolates from any source when tested in any of the following three media: Luria-Bertani broth supplemented with 2% glucose, tryptic soy broth (TSB), or 1/20th-strength TSB. Incubation was overnight at 30 degrees C under static conditions. Curli production and cellulose production were monitored by assessing morphotypes on Luria-Bertani agar without salt containing Congo red and by assessing fluorescence on Luria-Bertani agar containing calcofluor, respectively. One hundred percent of the clinical isolates exhibited curli biosynthesis, and 73% demonstrated cellulose production. All meat-related isolates formed curli, and 84% produced cellulose. A total of 80% of produce-related isolates produced curli, but only 52% produced cellulose. Crystal violet binding was not statistically different between isolates representing the three morphotypes when grown in TSB; however, significant differences were observed when strains were cultured in the two other media tested. These data demonstrate that the ability to form biofilms is not dependent on the source of the test isolate and suggest a relationship between crystal violet binding and morphotype, with curli- and cellulose-deficient isolates being least effective in biofilm formation.

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

Evaluation of fosfomycin activity against ESBL producing Enterobacteriaceae isolated from Iran.

PubMed

Kazemian, Hossein

2018-05-16

Rising rates of antimicrobial resistance among Enterobacteriaceae limit the use of reliably active forms of available drugs. The aim of this study was to investigate the prevalence of fosfomycin (US6794490B2) resistance gene among ESBL producing isolates in Iran. We tested 355 isolates of Enterobacteriacea collected from various clinical samples including urine, wounds, blood and other sources during June 2016 to July 2017. Antibiotic sensitivity and extended spectrum beta lactamase (ESBL) production were tested using agar dilution method according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. ESBL genes (blaTEM, bla SHV,bla CTX-M), plasmid-encoded fosfomycin resistance genes (fosA, fosB, fosA3 and fosC2) and chromosomal mutations (murA, glpT, uhpT) were detected by polymerase chain reaction (PCR). In this study, 151 of the 355 isolates were ESBL-positive. blaCTX-M (77%) was the most common gene followed by blaSHV (70%) and blaTEM (58%), either alone or in combination. Eighty nine percent (132/151) of the ESBL-positive isolates were MDR. Antimicrobial susceptibility rates were higher for fosfomycin (92.8%) and imipenem (35.5%) among ESBL-positive isolates. None of the ESBL- positive isolates harbored any mutations or plasmid-mediated fosfomycin resistance determinants. In conclusion, fosfomycin showed good antimicrobial activity against multidrug resistance ESBL- positive Enterobacteriaceae. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

A new approach to isolating siderophore-producing actinobacteria.

PubMed

Nakouti, I; Sihanonth, P; Hobbs, G

2012-07-01

This study was conducted to investigate the application of 2,2'-dipyridyl as a new approach to isolating siderophore-producing actinobacteria. Isolation of actinobacteria from soil was conducted by a soil dilution plate technique using starch-casein agar. Iron starvation was fostered by the incorporation of the iron chelator 2,2'-dipyridyl in the isolation medium. Pretreatment of the samples at an elevated temperature (40°C) ensured that the majority of nonsporulating bacteria were excluded. The survivors of this treatment were largely actinobacteria. Of the viable cultures grown in the presence of 2,2'-dipyridyl, more than 78-88% (average of three separate studies) were reported to produce siderophore-like compounds compared to 13-18% (average of three separate studies) when grown on the basic media in the absence of the chelating agent. The most prolific producers as assessed by the chrome azurol sulphate (CAS) assay were further characterized and found to belong to the genus Streptomyces. Selective pressure using 2,2'-dipyridyl as an iron-chelating agent in starch-casein media increased the isolation of siderophore-producing actinobacteria compared to the unamended medium. The study described represents a new approach to the isolation of siderophore-producing actinobacteria using a novel procedure that places a selection on cell population based upon the incorporation of a chelating agent in the medium. © 2012 The Authors. Letters in Applied Microbiology © 2012 The Society for Applied Microbiology.

Whole genome sequencing of ESBL-producing Escherichia coli isolated from patients, farm waste and canals in Thailand.

PubMed

Runcharoen, Chakkaphan; Raven, Kathy E; Reuter, Sandra; Kallonen, Teemu; Paksanont, Suporn; Thammachote, Jeeranan; Anun, Suthatip; Blane, Beth; Parkhill, Julian; Peacock, Sharon J; Chantratita, Narisara

2017-09-06

Tackling multidrug-resistant Escherichia coli requires evidence from One Health studies that capture numerous potential reservoirs in circumscribed geographic areas. We conducted a survey of extended β-lactamase (ESBL)-producing E. coli isolated from patients, canals and livestock wastewater in eastern Thailand between 2014 and 2015, and analyzed isolates using whole genome sequencing. The bacterial collection of 149 isolates consisted of 84 isolates from a single hospital and 65 from the hospital sewer, canals and farm wastewater within a 20 km radius. E. coli ST131 predominated the clinical collection (28.6%), but was uncommon in the environment. Genome-based comparison of E. coli from infected patients and their immediate environment indicated low genetic similarity overall between the two, although three clinical-environmental isolate pairs differed by ≤ 5 single nucleotide polymorphisms. Thai E. coli isolates were dispersed throughout a phylogenetic tree containing a global E. coli collection. All Thai ESBL-positive E. coli isolates were multidrug resistant, including high rates of resistance to tobramycin (77.2%), gentamicin (77.2%), ciprofloxacin (67.8%) and trimethoprim (68.5%). ESBL was encoded by six different CTX-M elements and SHV-12. Three isolates from clinical samples (n = 2) or a hospital sewer (n = 1) were resistant to the carbapenem drugs (encoded by NDM-1, NDM-5 or GES-5), and three isolates (clinical (n = 1) and canal water (n = 2)) were resistant to colistin (encoded by mcr-1); no isolates were resistant to both carbapenems and colistin. Tackling ESBL-producing E. coli in this setting will be challenging based on widespread distribution, but the low prevalence of resistance to carbapenems and colistin suggests that efforts are now required to prevent these from becoming ubiquitous.

Development of novel agar media for isolating guaiacol producing Alicyclobacillus spp.

PubMed

Chang, S S; Park, S H; Kang, D H

2013-06-03

The purpose of this study is to develop a selective and differential medium (SK2 agar) for isolating guaiacol producing Alicyclobacillus. Forty-one selected dyes and vanillic acid were incorporated in SK agar for screening selective and differential agents. Two guaiacol producing (1016, 1101) and two non-guaiacol producing (19220, C-GD 1-1) Alicyclobacillus isolates were streaked onto media and color differentiation of the isolates was assessed. Among 41 tested dyes, Chrome Azurol S (CAS) allowed color differentiation of the two types of Alicyclobacillus. Colonies of guaiacol producing Alicyclobacillus isolates appeared as dark purple to royal blue color with yellow background, whereas non-guaiacol producing Alicyclobacillus isolates produced cream colored colonies with yellow background. Vanillic acid not only served as a precursor for guaiacol formation but also inhibited non-guaiacol producing Alicyclobacillus. Non-guaiacol producing isolates did not grow on SK agar containing more than 70 ppm vanillic acid, whereas the recovery of guaiacol producing isolates was unaffected. When compared with other Alicyclobacillus isolation media, not only was SK2 agar capable of selectively recovering guaiacol-producing Alicyclobacillus, the degree of growth was also approximately equal if not better than orange serum agar, potato dextrose agar, and K agar. The development of SK2 agar provides the fruit juice industry with an inexpensive, simple to use alternative for the detection of guaiacol producing Alicyclobacillus. Copyright © 2013 Elsevier B.V. All rights reserved.

Clinical Saccharomyces cerevisiae isolates cannot cross the epithelial barrier in vitro.

PubMed

Pérez-Torrado, Roberto; Llopis, Silvia; Jespersen, Lene; Fernández-Espinar, Teresa; Querol, Amparo

2012-06-15

Saccharomyces cerevisiae is generally considered to be a safe organism and is essential to produce many different kinds of foods as well as being widely used as a dietary supplement. However, several isolates, which are genetically related to brewing and baking yeasts, have shown virulent traits, being able to produce human infections in immunodeficient patients. Previously it has been shown that the administration of S. cerevisiae clinical isolates can lead to systemic infections, reaching several organs in murine systems. In this work, we studied S. cerevisiae clinical isolates in an in vitro intestinal epithelial barrier model, comparing their behaviour with that of several strains of the related pathogens Candida glabrata and Candida albicans. The results showed that, in contrast to C. glabrata and C. albicans, S. cerevisiae was not able to cross the intestinal barrier. We concluded that S. cerevisiae can only perform opportunistic or passive crossings when epithelial barrier integrity is previously compromised. Copyright © 2012 Elsevier B.V. All rights reserved.

Electrochemical sensors for identifying pyocyanin production in clinical Pseudomonas aeruginosa isolates.

PubMed

Sismaet, Hunter J; Pinto, Ameet J; Goluch, Edgar D

2017-11-15

In clinical practice, delays in obtaining culture results impact patient care and the ability to tailor antibiotic therapy. Despite the advancement of rapid molecular diagnostics, the use of plate cultures inoculated from swab samples continues to be the standard practice in clinical care. Because the inoculation culture process can take between 24 and 48h before a positive identification test can be run, there is an unmet need to develop rapid throughput methods for bacterial identification. Previous work has shown that pyocyanin can be used as a rapid, redox-active biomarker for identifying Pseudomonas aeruginosa in clinical infections. However, further validation is needed to confirm pyocyanin production occurs in all clinical strains of P. aeruginosa. Here, we validate this electrochemical detection strategy using clinical isolates obtained from patients with hospital-acquired infections or with cystic fibrosis. Square-wave voltammetric scans of 94 different clinical P. aeruginosa isolates were taken to measure the concentration of pyocyanin. The results showed that all isolates produced measureable concentrations of pyocyanin with production rates correlated with patient symptoms and comorbidity. Further bioinformatics analysis confirmed that 1649 genetically sequenced strains (99.9%) of P. aeruginosa possess the two genes (PhzM and PhzS) necessary to produce pyocyanin, supporting the specificity of this biomarker. Confirming the production of pyocyanin by all clinically-relevant strains of P. aeruginosa is a significant step towards validating this strategy for rapid, point-of-care diagnostics. Copyright © 2017 Elsevier B.V. All rights reserved.

A study on the characterization of Propionibacterium acnes isolated from ocular clinical specimens.

PubMed

Sowmiya, Murali; Malathi, Jambulingam; Swarnali, Sen; Priya, Jeyavel Padma; Therese, Kulandai Lily; Madhavan, Hajib N

2015-10-01

There are only a few reports available on characterization of Propionibacterium acnes isolated from various ocular clinical specimens. We undertook this study to evaluate the role of P. acnes in ocular infections and biofilm production, and also do the phylogenetic analysis of the bacilli. One hundred isolates of P. acnes collected prospectively from ocular clinical specimens at a tertiary care eye hospital between January 2010 and December 2011, were studied for their association with various ocular disease conditions. The isolates were also subjected to genotyping and phylogenetic analysis, and were also tested for their ability to produce biofilms. Among preoperative conjunctival swabs, P. acnes was a probably significant pathogen in one case; a possibly significant pathogen in two cases. In other clinical conditions, 13 per cent isolates were probably significant pathogens and 38 per cent as possibly significant pathogens. The analysis of 16S rRNA gene revealed four different phylogenies whereas analysis of recA gene showed two phylogenies confirming that recA gene was more reliable than 16S rRNA with less sequence variation. Results of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) had 100 per cent concordance with phylogenetic results. No association was seen between P. acnes subtypes and biofilm production. RecA gene phylogenetic studies revealed two different phylogenies. RFLP technique was found to be cost-effective with high sensitivity and specificity in phylogenetic analysis. No association between P. acnes subtypes and pathogenetic ability was observed. Biofilm producing isolates showed increased antibiotic resistance compared with non-biofilm producing isolates.

Genotypic and phenotypic characterization of invasive neonatal Escherichia coli clinical isolates.

PubMed

Shakir, Salika Mehreen; Goldbeck, Jessica Marie; Robison, Denise; Eckerd, Annette Marie; Chavez-Bueno, Susana

2014-11-01

The objective of this study was to describe the clinical characteristics of neonates with Escherichia coli bacteremia and the antibiotic resistance pattern of the bacterial isolates. We assessed the isolates' genetic relatedness and virulence phenotypic characteristics in vitro. A total of 24 neonates with E. coli bacteremia were identified prospectively in a tertiary-care hospital. Clinical and antibiotic resistance data were investigated. The E. coli isolates were analyzed by multilocus sequence typing (MLST); the presence of the K1 capsule and their ability to invade intestinal epithelial cells were also assessed. Most newborns were very low birth weight infants. Overall, 75% of the isolates were ampicillin resistant and 17% were gentamicin and tobramycin nonsusceptible. MLST determined sequence types 95 and 131 (ST95 and ST131) predominated, with ST131 becoming significantly more prevalent recently. The K1 capsule was present in 50% of the isolates. ST131 isolates and those producing bacteremia in newborns younger than 7 days showed a highly invasive phenotype. Resistance to antibiotics currently used empirically to treat newborns is present in bacteremia-producing E. coli. Clonal spread among newborns of multidrug-resistant E. coli is possible; therefore, continued surveillance is needed. Identification of additional virulence factors associated with increased invasion in neonatal E. coli strains is important and further studies are warranted. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Genome-based analysis of Carbapenemase-producing Klebsiella pneumoniae isolates from German hospital patients, 2008-2014.

PubMed

Becker, Laura; Kaase, Martin; Pfeifer, Yvonne; Fuchs, Stephan; Reuss, Annicka; von Laer, Anja; Sin, Muna Abu; Korte-Berwanger, Miriam; Gatermann, Sören; Werner, Guido

2018-01-01

By using whole genome sequence data we aimed at describing a population snapshot of carbapenemase-producing K. pneumoniae isolated from hospitalized patients in Germany between 2008 and 2014. We selected a representative subset of 107 carbapenemase-producing K. pneumoniae clinical isolates possessing the four most prevalent carbapenemase types in Germany (KPC-2, KPC-3, OXA-48, NDM-1). Isolates were processed via illumina NGS. Data were analysed using different SNP-based mapping and de-novo assembly approaches. Relevant information was extracted from NGS data (antibiotic resistance determinants, wzi gene/ cps type, virulence genes). NGS data from the present study were also compared with 238 genome data from two previous international studies on K. pneumoniae. NGS-based analyses revealed a preferred prevalence of KPC-2-producing ST258 and KPC-3-producing ST512 isolates. OXA-48, being the most prevalent carbapenemase type in Germany, was associated with various K. pneumoniae strain types; most of them possessing IncL/M plasmid replicons suggesting a preferred dissemination of bla OXA-48 via this well-known plasmid type. Clusters ST15, ST147, ST258, and ST512 demonstrated an intermingled subset structure consisting of German and other European K. pneumoniae isolates. ST23 being the most frequent MLST type in Asia was found only once in Germany. This latter isolate contained an almost complete set of virulence genes and a K1 capsule suggesting occurrence of a hypervirulent ST23 strain producing OXA-48 in Germany. Our study results suggest prevalence of "classical" K. pneumonaie strain types associated with widely distributed carbapenemase genes such as ST258/KPC-2 or ST512/KPC-3 also in Germany. The finding of a supposed hypervirulent and OXA-48-producing ST23 K. pneumoniae isolates outside Asia is highly worrisome and requires intense molecular surveillance.

Beta-Lactamase Producing Escherichia coli Isolates in Imported and Locally Produced Chicken Meat from Ghana

PubMed Central

Rasmussen, Mette Marie; Opintan, Japheth A.; Frimodt-Møller, Niels; Styrishave, Bjarne

2015-01-01

The use of antibiotics in food animals is of public health concern, because resistant zoonotic pathogens can be transmitted to humans. Furthermore, global trade with food may rapidly spread multi-resistant pathogens between countries and even continents. The purpose of the study was to investigate whether imported chicken meat and meat from locally reared chicken are potential sources for human exposure to multi resistant Escherichia coli isolates. 188 samples from imported and locally produced chicken meat were sampled and analyzed. 153 bacteria isolates were successfully cultured and identified as E. coli using MALDI-ToF. Of these 109 isolates were from meat whereas the remaining 44 were isolated from the cloaca of locally reared live chickens. Antimicrobial susceptibility test was done on the identified E. coli isolates. Additionally, beta-lactamases production (ESBL and/or AmpC) were phenotypically confirmed on all isolates showing resistance to cefpodoxime. Beta-lactamase producing (BLP) E. coli meat isolates were further genotyped. Antimicrobial resistance to four antibiotic markers with highest resistance was detected more frequently in isolates from local chickens compared to imported chickens (tetracycline 88.9% vs. 57.5%, sulphonamide 75.0% vs. 46.6%, ampicillin 69.4% vs. 61.6% and trimethoprim 66.7% vs. 38.4%). Beta-lactamase production was found in 29 E. coli meat isolates, with 56.9% of them being multiple drug resistant (≥ 3). The predominant phylogroup identified was B1 followed by A and D, with similar distribution among the isolates from meat of locally reared chickens and imported chickens. Beta-lactamase producing genotype bla CTX-M-15 (50%; 10/20) was the most frequently drug resistant gene detected. More BLP E. coli isolates were found in imported chicken meat compared to locally reared chickens, demonstrating that these isolates may be spreading through food trade. In conclusion, both imported and locally produced chicken meats are potential

Beta-Lactamase Producing Escherichia coli Isolates in Imported and Locally Produced Chicken Meat from Ghana.

PubMed

Rasmussen, Mette Marie; Opintan, Japheth A; Frimodt-Møller, Niels; Styrishave, Bjarne

2015-01-01

The use of antibiotics in food animals is of public health concern, because resistant zoonotic pathogens can be transmitted to humans. Furthermore, global trade with food may rapidly spread multi-resistant pathogens between countries and even continents. The purpose of the study was to investigate whether imported chicken meat and meat from locally reared chicken are potential sources for human exposure to multi resistant Escherichia coli isolates. 188 samples from imported and locally produced chicken meat were sampled and analyzed. 153 bacteria isolates were successfully cultured and identified as E. coli using MALDI-ToF. Of these 109 isolates were from meat whereas the remaining 44 were isolated from the cloaca of locally reared live chickens. Antimicrobial susceptibility test was done on the identified E. coli isolates. Additionally, beta-lactamases production (ESBL and/or AmpC) were phenotypically confirmed on all isolates showing resistance to cefpodoxime. Beta-lactamase producing (BLP) E. coli meat isolates were further genotyped. Antimicrobial resistance to four antibiotic markers with highest resistance was detected more frequently in isolates from local chickens compared to imported chickens (tetracycline 88.9% vs. 57.5%, sulphonamide 75.0% vs. 46.6%, ampicillin 69.4% vs. 61.6% and trimethoprim 66.7% vs. 38.4%). Beta-lactamase production was found in 29 E. coli meat isolates, with 56.9% of them being multiple drug resistant (≥ 3). The predominant phylogroup identified was B1 followed by A and D, with similar distribution among the isolates from meat of locally reared chickens and imported chickens. Beta-lactamase producing genotype blaCTX-M-15 (50%; 10/20) was the most frequently drug resistant gene detected. More BLP E. coli isolates were found in imported chicken meat compared to locally reared chickens, demonstrating that these isolates may be spreading through food trade. In conclusion, both imported and locally produced chicken meats are potential

Emergence of Multidrug Resistance and Metallo-beta-lactamase Producing Acinetobacter baumannii Isolated from Patients in Shiraz, Iran

PubMed Central

Moghadam, MN; Motamedifar, M; Sarvari, J; Sedigh, Ebrahim-Saraie H; Mousavi, Same M; Moghadam, FN

2016-01-01

Background: Metallo-beta-lactamase (MβL) enzymes production is one of the most important resistance mechanisms against carbapenems in some bacteria including Acinetobacter baumannii. Aims: This study was aimed to determine the antimicrobial susceptibility and the prevalence of MβL among carbapenem-resistant isolates of A. baumannii. Materials and Methods: In this cross-sectional study from October 2012 to April 2013, 98 isolates were identified as A. baumannii using Microgen™ kits and confirmed by molecular method. These isolates were tested for antimicrobial susceptibilities by disk diffusion method according to the Clinical and Laboratory Standards Institute guidelines. Carbapenem-resistant isolates were further detected phenotypically by MβL minimal inhibitory concentration (MIC)-test strips, and subsequently positive MβL isolates were confirmed by polymerase chain reaction (PCR). Results: Overall, 98% (96/98) of A. baumannii isolates were detected as carbapenem-resistant by MIC test. Highest sensitivity to the tested antibiotic with 42.9% (42/98) was observed to colistin. Of 96 carbapenem-resistant isolates, 43 were phenotypically positive for MβL; out of 43 isolates, 37 were confirmed for the presence of MβL genes by PCR. Conclusion: The frequency of drug resistance among the clinical samples of A. baumannii isolated in our study against most of the antibiotics was very high. Moreover, all MβL producing isolates were multidrug resistance. Therefore, systematic surveillance to detect MβL producing bacteria and rational prescription and use of carbapenems could be helpful to prevent the spread of carbapenem resistance. PMID:27398247

The isolation of Cryptococcus neoformans from pigeon droppings and serotyping of naturally and clinically sourced isolates in China.

PubMed

Li, A; Nishimura, K; Taguchi, H; Tanaka, R; Wu, S; Miyaji, M

1993-10-01

This is the first report on the isolation of Cryptococcus neoformans from pigeon droppings in China and their serotypes. C. neoformans colonies which produced brown colonies on caffeic acid-cornmeal agar were found in Twenty-five out of thirty-six samples of pigeon droppings. Fifty-one colonies randomly picked from the positive samples were identified as C. neoformans by a commercially available kit for carbon source assimilation test and Christensen's urea agar. Forty (78%) out of the 51 strains were serotyped as A and 11 (22%) as AD. At the same time, seventeen out of nineteen clinical isolates were serotyped as A and 2 as B. There are three findings in our results. One is that only C. neoformans var. neoformans strains could be isolated from pigeon droppings, although the variety gattii strains were found in the clinical isolates obtained in the same geographic site in China. The second is that serotype A strains were most frequently seen in natural and clinical materials in the southeast part of China, and serotype AD strains were isolated in pigeon droppings but not in clinical materials. The third is that the coexistence of serotype A and AD cells of C. neoformans strains in same samples of pigeon droppings were observed.

Isolation, characterization, and diversity of novel radiotolerant carotenoid-producing bacteria.

PubMed

Asker, Dalal; Awad, Tarek S; Beppu, Teruhiko; Ueda, Kenji

2012-01-01

Carotenoids are natural pigments that exhibit many biological functions, such as antioxidants (i.e., promote oxidative stress resistance), membrane stabilizers, and precursors for vitamin A. The link between these biological activities and many health benefits (e.g., anticarcinogenic activity, prevention of chronic diseases, etc.) has raised the interest of several industrial sectors, especially in the cosmetics and pharmaceutical industries. The use of microorganisms in biotechnology to produce carotenoids is favorable by consumer and can help meet the growing demand for these bioactive compounds in the food, feed, and pharmaceutical industries. This methodological chapter details the development of a rapid and selective screening method for isolation and identification of carotenoid-producing microorganisms based on UV treatment, sequencing analysis of 16S rRNA genes, and carotenoids' analysis using rapid and effective High-Performance Liquid Chromatography-Diodearray-MS methods. The results of a comprehensive 16S rRNA gene-based phylogenetic analysis revealed a diversity of carotenoid-producing microorganisms (104 isolates) that were isolated at a high frequency from water samples collected at Misasa (Tottori, Japan), a region known for its high natural radioactivity content. These carotenoid-producing isolates were classified into 38 different species belonging to 7 bacterial classes (Flavobacteria, Sphingobacteria, α-Proteobacteria, γ-Proteobacteria, Deinococci, Actinobacteria, and Bacilli). The carotenoids produced by the isolates were zeaxanthin (6 strains), dihydroxyastaxanthin (24 strains), astaxanthin (27 strains), canthaxanthin (10 strains), and unidentified molecular species that were produced by the isolates related to Deinococcus, Exiguobacterium, and Flectobacillus. Here, we describe the methods used to isolate and classify these microorganisms.

Isolation of NDM-1-producing multidrug-resistant Pseudomonas putida from a paediatric case of acute gastroenteritis, India.

PubMed

Bhattacharya, D; Dey, S; Kadam, S; Kalal, S; Jali, S; Koley, H; Sinha, R; Nag, D; Kholkute, S D; Roy, S

2015-05-01

Pseudomonas putida is an uncommon opportunistic pathogen, usually susceptible to antimicrobial agents. Data concerning resistance to antimicrobial agents in clinical P. putida isolates are limited. To the best of our knowledge we report for the first time the isolation of NDM-1-producing multidrug-resistant P. putida from a case of acute gastroenteritis. The isolate showed resistance to a wide range of antimicrobials, including fluoroquinolones, third-generation cephalosporins and carbapenems. The isolate also exhibited multiple mutations in the quinolone resistance determining region and showed the presence of qepA, bla TEM , bla OXA1 and bla OXA7 genes. The present study highlights the importance of looking for the relatively rare aetiological agents in clinical samples that do not yield common pathogens.

Isolation of NDM-1-producing multidrug-resistant Pseudomonas putida from a paediatric case of acute gastroenteritis, India

PubMed Central

Bhattacharya, D.; Dey, S.; Kadam, S.; Kalal, S.; Jali, S.; Koley, H.; Sinha, R.; Nag, D.; Kholkute, S.D.; Roy, S.

2015-01-01

Pseudomonas putida is an uncommon opportunistic pathogen, usually susceptible to antimicrobial agents. Data concerning resistance to antimicrobial agents in clinical P. putida isolates are limited. To the best of our knowledge we report for the first time the isolation of NDM-1-producing multidrug-resistant P. putida from a case of acute gastroenteritis. The isolate showed resistance to a wide range of antimicrobials, including fluoroquinolones, third-generation cephalosporins and carbapenems. The isolate also exhibited multiple mutations in the quinolone resistance determining region and showed the presence of qepA, blaTEM, blaOXA1 and blaOXA7 genes. The present study highlights the importance of looking for the relatively rare aetiological agents in clinical samples that do not yield common pathogens. PMID:25893095

Characterization of Enterobacteriaceae isolates obtained from a tertiary care hospital in Mexico, which produces extended-spectrum β-lactamase.

PubMed

Morfín-Otero, Rayo; Mendoza-Olazarán, Soraya; Silva-Sánchez, Jesús; Rodríguez-Noriega, Eduardo; Laca-Díaz, Jorge; Tinoco-Carrillo, Perla; Petersen, Luis; López, Perla; Reyna-Flores, Fernando; Alcantar-Curiel, Dolores; Garza-Ramos, Ulises; Garza-González, Elvira

2013-10-01

The prevalence and genetic characteristics of Escherichia coli and Klebsiella pneumoniae clinical isolates producing extended-spectrum β-lactamase (ESBL) were examined. Between October 2010 and March 2011, E. coli (n=460) and K. pneumoniae (n=78) isolates were collected at a tertiary care hospital in Guadalajara, Mexico. The minimum inhibitory concentration (MIC) for each isolate was determined using a broth microdilution method, and ESBL production was assayed. The presence of β-lactamase genes, blaSHV, blaCTX-M, and blaTLA-1, was detected by PCR and confirmed with sequencing. Only ESBL-producing isolates were further subjected to pulsed-field gel electrophoresis (PFGE) and plasmid profiling. All of the ESBL isolates were multidrug resistant and 75/460 (16.3%) E. coli isolates and 21/78 (26.9%) K. pneumoniae isolates were found to produce ESBL. For the E. coli isolates, >95% susceptibility to amikacin, meropenem, fosfomycin, imipenem, and nitrofurantoin was observed. For K. pneumoniae, similar results were obtained, with discrepancies observed for gentamicin and nitrofurantoin. PFGE further identified eleven pulsotypes for E. coli and three clusters of K. pneumoniae. CTX-M-15 was detected in 85% of ESBL-producing E. coli and in 76% of ESBL-producing K. pneumoniae. In contrast, SHV-5 ESBL was identified in 17% of E. coli isolates and in 86% of K. pneumoniae isolates. The bla-TLA-1 gene was not detected in any of the 96 isolates analyzed. Overall, CTX-M-15 and SHV-5 were found to have a high rate of spread throughout the hospital and were associated with strong multidrug resistance.

Distribution and antimicrobial susceptibility profile of extended-spectrum β-lactamase-producing Proteus mirabilis strains recently isolated in Japan.

PubMed

Kanayama, Akiko; Kobayashi, Intetsu; Shibuya, Kazutoshi

2015-02-01

Here we report on the prevalence of extended-spectrum β-lactamase (ESBL)-producing Proteus mirabilis from a nationwide antimicrobial resistance survey in different geographical regions of Japan. A total of 799 P. mirabilis isolates recovered between July 2009 and June 2010 from 314 healthcare facilities were characterised according to ESBL production, source, location and antimicrobial susceptibility pattern. ESBL production was found in 364 (45.6%) of the isolates, among which 354 (97.3%) produced CTX-M-2 group β-lactamases. Of the 349 ESBL-producing isolates in which the inpatient or outpatient status of the source was known, 324 (92.8%) were from inpatients and 25 (7.2%) were from outpatients (P<0.05). Results of pulsed-field gel electrophoresis (PFGE) analysis performed on 66 of the ESBL-producers generated a distribution of PFGE patterns into 21 groups. Genetic relatedness was seen among isolates within a region, which is consistent with horizontal transmission. With respect to the frequency of ESBL-producers by specimen source, 12/14 (85.7%) central venous catheter specimens yielded ESBL-producing P. mirabilis compared with 159/405 (39.3%), 119/209 (56.9%), 42/77 (54.5%) and 20/49 (40.8%), respectively, for isolates from urine, sputum, decubitus ulcer and wound specimens. Among the ESBL-producers, non-susceptibility to ciprofloxacin was found in 74.2% of the ESBL-producing isolates compared with 17.7% of the ESBL-non-producing isolates. These results show that approximately one-half of the P. mirabilis isolates from clinical specimens in Japan are ESBL-producers and that the potential for concomitant fluoroquinolone resistance must also be considered. Copyright © 2014 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Medicinal Plants Used by a Mbyá-Guarani Tribe Against Infections: Activity on KPC-Producing Isolates and Biofilm-Forming Bacteria.

PubMed

Brandelli, Clara Lia Costa; Ribeiro, Vanessa Bley; Zimmer, Karine Rigon; Barth, Afonso Luís; Tasca, Tiana; Macedo, Alexandre José

2015-11-01

The traditional use of medicinal plants for treatment of infectious diseases by an indigenous Mbyá-Guarani tribe from South Brazil was assessed by evaluating the antibiotic and antibiofilm activities against relevant bacterial pathogens. Aqueous extracts from 10 medicinal plants were prepared according to indigenous Mbyá-Guarani traditional uses. To evaluate antibiotic (OD600) and antibiofilm (crystal violet method) activities, Pseudomonas aeruginosa ATCC 27853, Staphylococcus epidermidis ATCC 35984 and seven multi-drug resistant Klebsiella pneumoniae carbapenemase (KPC)-producing bacterial clinical isolates were challenged with the extracts. Furthermore, the susceptibility profile of KPC-producing bacteria and the ability of these isolates to form biofilm were evaluated. The plants Campomanesia xanthocarpa, Maytenus ilicifolia, Bidens pilosa and Verbena sp. showed the best activity against bacterial growth and biofilm formation. The majority of KPC-producing isolates, which showed strong ability to form biofilm and a multidrug resistance profile, was inhibited by more than 50% by some extracts. The Enterobacter cloacae (KPC 05) clinical isolate was the only one resistant to all extracts. This study confirms the importance of indigenous traditional medicinal knowledge and describes for the first time the ability of these plants to inhibit biofilm formation and/or bacterial growth of multi-drug resistant KPC-producing isolates.

High prevalence of sequence type 131 isolates producing CTX-M-15 among ESBL-producing Escherichia coli strains in north-east Iran.

PubMed

Moghanni, Marzie; Ghazvini, Kiarash; Farsiani, Hadi; Namaei, Mohammad Hasan; Derakhshan, Mohammad; Yousefi, Masoud; Maragheh, Alimohammad; Jamehdar, Saeid Amel

2018-05-25

The recent expansion of extended-spectrum-β-lactamase (ESBL)-producing Escherichia coli (E. coli) is a worldwide problem. The purpose of this study was to investigate the molecular characteristic of ESBL-producing E. coli strains in Mashhad, located in the northeast of Iran. A total of 455 clinical isolates of E. coli were collected at three hospitals in Mashhad between April and September 2015. Antibiotic susceptibility was determined with the Kirby Bauer disk diffusion test. The Combination Disc Test (CDT) was performed for the phenotypic detection of ESBLs. PCR was used for screening isolates for ESBLs typing. Phylogenetic groups and sequence type 131 were determined by multiplex-PCR. The prevalence of ESBL-producing E. coli in the collected E. coli strains was 52% (235/455). Among the 235 ESBL producer strains, 94.4% (222/235) tested positive for the CTX-M type, while 115 (48.9%), 92 (39%) and 21 (8.9%) strains were positive for TEM, OXA and SHV, respectively. Moreover, CTX-M-15 (94.1%, 209/222) was the most common ESBL-producing E. coli. Based on multiplex-PCR, the phylogenetic group B2 was the most predominant (169 isolates, 71.9%), followed by D (32, 13.6%), A (21, 8.9%), and B1 (13, 5.5%). Of the 169 groups of B2 isolates, ST131 (151, 89.3%) was the predominant clonal group. The obtained results revealed that an urgent investigation of the source and the transmission pathways of the CTX-M15-B2ST131 E. coli clone was needed to countervail this emergent public health problem. Copyright © 2018. Published by Elsevier Ltd.

Epidemiology of Extended-Spectrum β-Lactamase-Producing Enterobacter Isolates in a Spanish Hospital during a 12-Year Period

PubMed Central

Cantón, Rafael; Oliver, Antonio; Coque, Teresa M.; Varela, María del Carmen; Pérez-Díaz, José Claudio; Baquero, Fernando

2002-01-01

Fifteen Enterobacter clinical isolates (11 Enterobacter cloacae isolates, 3 Enterobacter aerogenes isolates, and 1 Enterobacter gergoviae isolate), representing 0.4% of all Enterobacter isolates recovered in our hospital from 1989 to 2000, were suspected of harboring an extended-spectrum β-lactamase (ESBL). These isolates were recovered from 14 different patients. ESBLs were transferred by conjugation into an Escherichia coli recipient strain. Pulsed-field gel electrophoresis (PFGE) revealed a single clone of E. aerogenes and six different clones of E. cloacae. Four of these E. cloacae clonal types were represented by only one isolate each, but the other two were represented by three and four isolates, respectively. Isoelectric focusing, susceptibility phenotyping, PCR analysis, and sequencing demonstrated the presence of three different ESBLs. The most frequent was the recently characterized CTX-M-10 ESBL, which was found in the E. gergoviae isolate and in all but one of the E. cloacae isolates. The remaining E. cloacae isolate harbored a TEM-27 ESBL, and the three E. aerogenes isolates harbored a TEM-24 ESBL. PFGE revealed that our E. aerogenes strain was indistinguishable from the French TEM-24-producing E. aerogenes endemic clone. Although a low prevalence of ESBL-producing Enterobacter isolates was found in our institution over a 12-year period, a diversity of nonepidemic E. cloacae clones was detected, as was the persistence of the CTX-M-10 β-lactamase. The presence of the TEM-24-producing E. aerogenes French clone in our institution also demonstrates the intercountry dissemination of ESBL-producing isolates. PMID:11923338

Emergence of Carbapenemase-Producing Escherichia coli Isolated from Companion Animals in Algeria.

PubMed

Yousfi, Massilia; Touati, Abdelaziz; Mairi, Assia; Brasme, Lucien; Gharout-Sait, Alima; Guillard, Thomas; De Champs, Christophe

2016-06-01

The emergence and worldwide spread of carbapenemase-producing Enterobacteriaceae is of great concern to public health. The aim of this study was to investigate the occurrence of carbapenemase-producing Escherichia coli in companion animals in Algeria. Two hundred fecal samples were obtained from healthy and diseased dogs and cats in one veterinary office and private owners in Bejaia city, Algeria, during November 2014 to March 2015. Isolates were screened by polymerase chain reaction for the presence of carbapenemase, acquired plasmidic AmpC (pAmpC) and extended-spectrum beta-lactamase genes. Five carbapenemase-producing E. coli isolates were detected including four OXA-48-producing isolates and one isolate producing NDM-5. Coexpression of ESBL and pAmpC genes was observed in these isolates. Phylogenetic grouping revealed that these isolates belonged to A and D phylogroups. The results of this study show that carbapenemase-producing E. coli spread to the companion animals in Algeria.

Route of infection alters virulence of neonatal septicemia Escherichia coli clinical isolates

PubMed Central

Cole, Bryan K.; Scott, Edgar; Ilikj, Marko; Bard, David; Akins, Darrin R.; Dyer, David W.

2017-01-01

Escherichia coli is the leading cause of Gram-negative neonatal septicemia in the United States. Invasion and passage across the neonatal gut after ingestion of maternal E. coli strains produce bacteremia. In this study, we compared the virulence properties of the neonatal E. coli bacteremia clinical isolate SCB34 with the archetypal neonatal E. coli meningitis strain RS218. Whole-genome sequencing data was used to compare the protein coding sequences among these clinical isolates and 33 other representative E. coli strains. Oral inoculation of newborn animals with either strain produced septicemia, whereas intraperitoneal injection caused septicemia only in pups infected with RS218 but not in those injected with SCB34. In addition to being virulent only through the oral route, SCB34 demonstrated significantly greater invasion and transcytosis of polarized intestinal epithelial cells in vitro as compared to RS218. Protein coding sequences comparisons highlighted the presence of known virulence factors that are shared among several of these isolates, and revealed the existence of proteins exclusively encoded in SCB34, many of which remain uncharacterized. Our study demonstrates that oral acquisition is crucial for the virulence properties of the neonatal bacteremia clinical isolate SCB34. This characteristic, along with its enhanced ability to invade and transcytose intestinal epithelium are likely determined by the specific virulence factors that predominate in this strain. PMID:29236742

Prevalence of Class D Carbapenemases among Extended-Spectrum β-Lactamases Producing Escherichia coli Isolates from Educational Hospitals in Shahrekord

PubMed Central

Damavandi, Mohammad-Sadegh; Latif Pour, Mohammad

2016-01-01

Introduction Extended-spectrum β-lactamases (ESBLs) are a set of plasmid-borne, various and quickly evolving enzymes that are a main therapeutic issue now-a-days for inpatient and outpatient treatment. Aim The aim of this study was to determine multi-drug resistance (MDR) and ESBLs producing E. coli strains, prevalence of class D Carbapenemases among ESBLs producing Escherichia coli isolates from educational hospitals in Shahrekord, Iran. Materials and Methods Uropathogenic Escherichia coli strains were isolated from patients with Urinary Tract Infections (UTIs). The agar disc diffusion test was used to characterize the antimicrobial sensitivity of the E. coli isolates. The ESBL positive strains were identified by phenotypic double-disk synergy test, by third-generation cephalosporin in combination with or without clavulanic acid. Multiplex PCR was carried out for detection of the three families of OXA-type carbapenamases including OXA-23, OXA-24, and OXA-48 in E. coli strains. Results All bacterial isolates were susceptible to meropenem. Ninety isolates produced ESBL, 55 E. coli isolates from inpatients, and 35 isolates from outpatients, with a significant association (p< 0.05). The prevalence of OXA-23, OXA-24, and OXA-48 in the ESBLs producing isolates was respectively 21%, 18%, and 11% for inpatients, and 10%, 8%, and 6% for outpatients. Conclusion ESBL-producing E. coli isolates are also a major threat in the clinical setting. The findings of this study indicated the high occurrence of ESBLs and multiple antibiotic resistance in E. coli isolates. PMID:27462579

Characterization of elastase-deficient clinical isolates of Pseudomonas aeruginosa.

PubMed Central

Hamood, A N; Griswold, J; Colmer, J

1996-01-01

Elastase production in Pseudomonas aeruginosa is regulated by the lasR, lasI, rhlR, and rhlI genes. Recently, we have analyzed several clinical isolates of P. aeruginosa for the production of elastase and other extracellular virulence factors. Four of these isolates (CIT1, CIW5, CIW7, and CIW8) produced no elastolytic activity. We have characterized these isolates with respect to their elastase-deficient phenotype. Elastase was detected by immunoblotting experiments using elastase-specific antiserum. We also determined the presence of IasB and IasR mRNAs by Northern (RNA) blot hybridization experiments using lasB and lasR internal probes, respectively. None of the four elastase-deficient strains produced either the elastase protein or the lasB mRNA. Complementation experiments (using plasmids carrying either the lasB or the lasR gene) were conducted to determine if the isolates carry defective lasB or lasR genes. The presence of either a lasB or a lasR plasmid in CIW7 and CIW8 resulted in the production of very low levels of elastase and lasB mRNA. Neither elastase nor lasB mRNA was detected in CIT1 and CIW5 carrying the lasB plasmid. The presence of the lasR plasmid in CIT1 and CIW5 resulted in the production of lasB mRNA and elastase protein in CIW5 only. All elastase-deficient strains produced detectable levels of lasR mRNA which were enhanced in the presence of the lasR plasmid. The Pseudomonas autoinducer (which is encoded by lasI) was also produced by all strains. CIT1 produced both hemolysin and alkaline protease but was defective in pyocyanin production. These results suggest that (i) CIT1 may contain a defect in a lasB-regulatory gene, (ii) CIW5 carries a defect within lasR, and (iii) the defect in isolates CIW7 and CIW8 affects the efficiency of lasB transcription. PMID:8757847

Virulence attributes in Brazilian clinical isolates of Pseudomonas aeruginosa.

PubMed

Silva, Lívia V; Galdino, Anna Clara M; Nunes, Ana Paula F; dos Santos, Kátia R N; Moreira, Beatriz M; Cacci, Luciana C; Sodré, Cátia L; Ziccardi, Mariangela; Branquinha, Marta H; Santos, André L S

2014-11-01

Pseudomonas aeruginosa is an opportunistic human pathogen responsible for causing a huge variety of acute and chronic infections with significant levels of morbidity and mortality. Its success as a pathogen comes from its genetic/metabolic plasticity, intrinsic/acquired antimicrobial resistance, capacity to form biofilm and expression of numerous virulence factors. Herein, we have analyzed the genetic variability, antimicrobial susceptibility as well as the production of metallo-β-lactamases (MBLs) and virulence attributes (elastase, pyocyanin and biofilm) in 96 strains of P. aeruginosa isolated from different anatomical sites of patients attended at Brazilian hospitals. Our results revealed a great genetic variability, in which 86 distinct RAPD types (89.6% of polymorphisms) were detected. Regarding the susceptibility profile, 48 strains (50%) were resistant to the antimicrobials, as follows: 22.92% to the three tested antibiotics, 12.5% to both imipenem and meropenem, 11.46% to ceftazidime only, 2.08% to imipenem only and 1.04% to both ceftazidime and meropenem. Out of the 34 clinical strains of P. aeruginosa resistant to both imipenem and meropenem, 25 (73.53%) were MBL producers by phenotypic method while 12 (35.29%) were PCR positive for the MBL gene SPM-1. All P. aeruginosa strains produced pyocyanin, elastase and biofilm, although in different levels. Some associations were demonstrated among the susceptibility and/or production of these virulence traits with the anatomical site of strain isolation. For instance, almost all strains isolated from urine (85.71%) were resistant to the three antibiotics, while the vast majority of strains isolated from rectum (95%) and mouth (66.67%) were susceptible to all tested antibiotics. Urine isolates produced the highest pyocyanin concentration (20.15±5.65 μg/ml), while strains isolated from pleural secretion and mouth produced elevated elastase activity (1441.43±303.08 FAU) and biofilm formation (OD590 0.676±0

Comparison of atypical Brachyspira spp. clinical isolates and classic strains in a mouse model of swine dysentery.

PubMed

Burrough, Eric; Strait, Erin; Kinyon, Joann; Bower, Leslie; Madson, Darin; Schwartz, Kent; Frana, Timothy; Songer, J Glenn

2012-12-07

Multiple Brachyspira spp. can colonize the porcine colon, and the presence of the strongly beta-hemolytic Brachyspira hyodysenteriae is typically associated with clinical swine dysentery. Recently, several Brachyspira spp. have been isolated from the feces of pigs with clinical disease suggestive of swine dysentery, yet these isolates were not identified as B. hyodysenteriae by genotypic or phenotypic methods. This study used a mouse model of swine dysentery to compare the pathogenic potential of seventeen different Brachyspira isolates including eight atypical clinical isolates, six typical clinical isolates, the standard strain of B. hyodysenteriae (B204), and reference strains of Brachyspira intermedia and Brachyspira innocens. Results revealed that strongly beta-hemolytic isolates induced significantly greater cecal inflammation than weakly beta-hemolytic isolates regardless of the genetic identification of the isolate, and that strongly beta-hemolytic isolates identified as 'Brachyspira sp. SASK30446' and B. intermedia by PCR produced lesions indistinguishable from those caused by B. hyodysenteriae in this model. Copyright © 2012 Elsevier B.V. All rights reserved.

Clinical and molecular epidemiology of hospital Enterococcus faecalis isolates in eastern France.

PubMed

Mulin, Blandine; Bailly, Pascale; Thouverez, Michelle; Cailleaux, Vincent; Cornette, Christian; Dupont, Marie-Jeanne; Talon, Daniel

1999-03-01

OBJECTIVE: To report on the occurrence of Enterococcus faecalis hospital isolates obtained during 1 year in hospitals in the Franche-Comté region of France. METHODS: Clinical isolates of E. faecalis of different antibiotic susceptibility phenotypes from hospitalized patients were characterized by pulsed-field gel electrophoresis. Patients with positive cultures were investigated by three case-control studies to identify risk factors for colonization/infection. RESULTS: The crude incidence of colonization/infection was 2.37%, and 4-day and 7-day colonization rates after admission were 10.0% and 6.36%, respectively. The rates of high-level resistance to kanamycin (HLKR) and to gentamicin (HLGR) were 47.1% and 7.1%, respectively. No isolate was resistant to glycopeptides or produced beta-lactamase. The 209 hospital isolates obtained during the study yielded 98 major DNA patterns, of which two were major epidemic patterns including HLKR isolates. No single factor was significantly associated with colonization/infection by HLKR isolates. The length of hospitalization before isolation was associated with colonization by HLGR isolates. CONCLUSIONS: The isolation frequency of E. faecalis strains with acquired resistance to aminoglycoside antibiotics, and the wide dissemination of resistant strains with characteristics that allow them to persist and spread, argue for further large prospective surveys of clinical isolates of E. faecalis in hospitals.

Clinical Epidemiology and Molecular Analysis of Extended-Spectrum-β-Lactamase-Producing Escherichia coli in Nepal: Characteristics of Sequence Types 131 and 648

PubMed Central

Sherchan, Jatan Bahadur; Miyoshi-Akiyama, Tohru; Ohmagari, Norio; Kirikae, Teruo; Nagamatsu, Maki; Tojo, Masayoshi; Ohara, Hiroshi; Sherchand, Jeevan B.; Tandukar, Sarmila

2015-01-01

Recently, CTX-M-type extended-spectrum-β-lactamase (ESBL)-producing Escherichia coli strains have emerged worldwide. In particular, E. coli with O antigen type 25 (O25) and sequence type 131 (ST131), which is often associated with the CTX-M-15 ESBL, has been increasingly reported globally; however, epidemiology reports on ESBL-producing E. coli in Asia are limited. Patients with clinical isolates of ESBL-producing E. coli in the Tribhuvan University teaching hospital in Kathmandu, Nepal, were included in this study. Whole-genome sequencing of the isolates was conducted to analyze multilocus sequence types, phylotypes, virulence genotypes, O25b-ST131 clones, and distribution of acquired drug resistance genes. During the study period, 105 patients with ESBL-producing E. coli isolation were identified, and the majority (90%) of these isolates were CTX-M-15 positive. The most dominant ST was ST131 (n = 54; 51.4%), followed by ST648 (n = 15; 14.3%). All ST131 isolates were identified as O25b-ST131 clones, subclone H30-Rx. Three ST groups (ST131, ST648, and non-ST131/648) were compared in further analyses. ST648 isolates had a proportionally higher resistance to non-β-lactam antibiotics and featured drug-resistant genes more frequently than ST131 or non-ST131/648 isolates. ST131 possessed the most virulence genes, followed by ST648. The clinical characteristics were similar among groups. More than 38% of ESBL-producing E. coli isolates were from the outpatient clinic, and pregnant patients comprised 24% of ESBL-producing E. coli cases. We revealed that the high resistance of ESBL-producing E. coli to multiple classes of antibiotics in Nepal is driven mainly by CTX-M-producing ST131 and ST648. Their immense prevalence in the communities is a matter of great concern. PMID:25824221

Evaluation of Antioxidant Activity and Growth Control Properties of Nonoscale Structure Produced from Aloe vera var. littoralis Extract on Clinical Isolates of Salmonella.

PubMed

Ranjbar, Reza; Arjomandzadegan, Mohammad; Hosseiny, Hossein

2017-07-31

The aim of the study was to examine antibacterial properties of microemulsion structure produced from Aloe vera var. littoralis extract as a new tool of nanoscale drug-like materials. Aloe vera var. littoralis ( A. littoralis ) extract was prepared by distillation method. A nonocarrier structure in the microemulsion system was prepared from the extract. Serial concentrations were prepared from 8 mg/mL extract and the nonocarrier containing 0.1 mg/mL pure extract and were evaluated by a disk diffusion method for 35 Salmonella clinical isolates. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by microbroth dilution assay using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) method by an enzyme-linked immunosorbent assay(ELISA) Microplate Reader apparatus. Antioxidant activity of the extract was determined by measuring the ferric reducing ability of plasma (FRAP) assay. From 35 clinical isolates of Salmonella , 17 isolates-including resistant isolates of S.E.1103 and S.E.49-had a zone of inhibition (ZI) of 7 to 32 mm in 0.007 mg/mL of the extract. S.E.76 isolate exposed to 30 µg/mL ceftazidime disk had a ZI of 12 mm but had 10 mm in 7µg/mL of A. littoralis extract. The inhibitory effect of a nanocarrier at a concentration of 25 µg/mL by 20 mm ZI was comparable by the ceftazidime (30 µg/mL) effect. MIC 50 was 0.25 mg/mL and MBC 50 was 0.5 mg/mL by MTT method for the extract. It was shown that A.littoralis extract had antioxidant activity of 31.67 µM/mg that could be increased based on concentration. It was concluded that the nanocarrier had a significant effect on the studied isolates in comparison with ordinary antibiotics and had potential for use as a natural antioxidant and antimicrobial material in complementary medicine.

First outbreak of VIM-2 metallo-β-lactamase-producing Pseudomonas aeruginosa in The Netherlands: microbiology, epidemiology and clinical outcomes.

PubMed

Van der Bij, A K; Van Mansfeld, R; Peirano, G; Goessens, W H F; Severin, J A; Pitout, J D D; Willems, R; Van Westreenen, M

2011-06-01

This study was designed to investigate the prevalence and characteristics of metallo-β-lactamase (MBL)-producing Pseudomonas aeruginosa in a tertiary care centre in The Netherlands, a country that is considered to have a low prevalence of antibiotic-resistant bacteria. Imipenem-resistant P. aeruginosa isolates cultured from clinical specimens during 2008-2009 were analysed phenotypically and molecularly by polymerase chain reaction (PCR) with sequencing. Genotyping was performed by multiple-locus variable-number tandem repeat (VNTR) analysis (MLVA). Clinical information was obtained by electronic chart review for all patients infected or colonised with an imipenem-resistant P. aeruginosa isolate that was included in the study. In total, 106 imipenem-resistant P. aeruginosa isolates were included. The bla(VIM-2) gene was detected in 35/106 isolates (33%) and was associated with integrons. Compared with non-MBL-producing imipenem-resistant P. aeruginosa, VIM-2 MBL-producing isolates showed higher rates of multidrug resistance. Patients with VIM-2 MBL-producing isolates were more likely to be admitted to the Intensive Care Unit (ICU) and had a higher risk of invasive infection, including development of bacteraemia. MLVA identified two separate VIM-2 MBL-producing clones, responsible for outbreaks in the ICU but also affecting 10 other departments. This is the first reported outbreak of VIM-2 MBL-producing P. aeruginosa in The Netherlands. Once introduced, VIM-2 MBL-producing P. aeruginosa cause significant infections and are easily spread within the hospital setting. Copyright © 2011 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Prevalence of genomic island PAPI-1 in clinical isolates of Pseudomonas aeruginosa in Iran.

PubMed

Sadeghifard, Nourkhoda; Rasaei, Seyedeh Zahra; Ghafourian, Sobhan; Zolfaghary, Mohammad Reza; Ranjbar, Reza; Raftari, Mohammad; Mohebi, Reza; Maleki, Abbas; Rahbar, Mohammad

2012-03-01

Pseudomonas aeruginosa, a gram-negative rod-shaped bacterium, is an opportunistic pathogen, which causes various serious diseases in humans and animals. The aims of this study were to evaluate of the presence of genomic island PAPI-1 in Pseudomonas aeruginosa isolated from Reference Laboratory of Ilam, Milad Hospital and Emam Khomeini Hospital, Iran and to study the frequency of extended spectrum beta-lactamases (ESBLs) among isolates. Forty-eight clinical isolates of P. aeruginosa were obtained during April to September 2010, and were evaluated for ESBLs by screening and confirmatory disk diffusion methods and PAPI-1 by PCR. Fifteen of 48 P. aeruginosa isolates were positive for ESBLs and 17 isolates positive for PAPI-1. This was first study of the prevalence of PAPI-1 in clinical isolates of P. aeruginosa in Iran, showing that most of PAPI-1 positive strains had high levels of antibiotic resistance and produced ESBLs.

Isolation and identification of biocellulose-producing bacterial strains from Malaysian acidic fruits.

PubMed

Voon, W W Y; Rukayadi, Y; Meor Hussin, A S

2016-05-01

Biocellulose (BC) is pure extracellular cellulose produced by several species of micro-organisms that has numerous applications in the food, biomedical and paper industries. However, the existing biocellulose-producing bacterial strain with high yield was limited. The aim of this study was to isolate and identify the potential biocellulose-producing bacterial isolates from Malaysian acidic fruits. One hundred and ninety-three bacterial isolates were obtained from 19 local acidic fruits collected in Malaysia and screened for their ability to produce BC. A total of 15 potential bacterial isolates were then cultured in standard Hestrin-Schramm (HS) medium statically at 30°C for 2 weeks to determine the BC production. The most potent bacterial isolates were identified using 16S rRNA gene sequence analysis, morphological and biochemical characteristics. Three new and potent biocellulose-producing bacterial strains were isolated from soursop fruit and identified as Stenotrophomonas maltophilia WAUPM42, Pantoea vagans WAUPM45 and Beijerinckia fluminensis WAUPM53. Stenotrophomonas maltophilia WAUPM42 was the most potent biocellulose-producing bacterial strain that produced the highest amount of BC 0·58 g l(-1) in standard HS medium. Whereas, the isolates P. vagans WAUPM45 and B. fluminensis WAUPM53 showed 0·50 and 0·52 g l(-1) of BC production, respectively. Biocellulose (BC) is pure extracellular cellulose that is formed by many micro-organisms in the presence of carbon source and acidic condition. It can replace plant-based cellulose in multifarious applications due to its unique characteristics. In this study, three potential biocellulose-producing bacterial strains were obtained from Malaysian acidic fruits and identified as Stenotrophomonas maltophilia WAUPM42, Pantoea vagans WAUPM45 and Beijerinckia fluminensis WAUPM53. This study reports for the first time the new biocellulose-producing bacterial strains isolated from Malaysian acidic fruits. © 2016 The

Isolation of antimicrobial producing Actinobacteria from soil samples.

PubMed

Elbendary, Afaf Ahmed; Hessain, Ashgan Mohamed; El-Hariri, Mahmoud Darderi; Seida, Ahmed Adel; Moussa, Ihab Mohamed; Mubarak, Ayman Salem; Kabli, Saleh A; Hemeg, Hassan A; El Jakee, Jakeen Kamal

2018-01-01

Emergence of multidrug resistant bacteria has made the search for novel bioactive compounds from natural and unexplored habitats a necessity. Actinobacteria have important bioactive substances. The present study investigated antimicrobial activity of Actinobacteria isolated from soil samples of Egypt. One hundred samples were collected from agricultural farming soil of different governorates. Twelve isolates have produced activity against the tested microorganisms ( S. aureus , Bacillus cereus , E. coli , K. pneumoniae , P. aeruginosa , S. Typhi, C. albicans , A. niger and A. flavus ). By VITEK 2 system version: 07.01 the 12 isolates were identified as Kocuria kristinae , Kocuria rosea , Streptomyces griseus , Streptomyces flaveolus and Actinobacteria . Using ethyl acetate extraction method the isolates culture's supernatants were tested by diffusion method against indicator microorganisms. These results indicate that Actinobacteria isolated from Egypt farms could be sources of antimicrobial bioactive substances.

Molecular typing of environmental and clinical strains of Vibrio vulnificus isolated in the northeastern USA.

PubMed

Reynaud, Yann; Pitchford, Steven; De Decker, Sophie; Wikfors, Gary H; Brown, Christopher L

2013-01-01

Vibrio vulnificus is a ubiquitous marine bacterium that is responsible for infections and some seafood-related illnesses and deaths in the United States, mainly in individuals with compromised health status in the Gulf of Mexico region. Most phylogenetic studies focus on V. vulnificus strains isolated in the southern United States, but almost no genetic data are available on northeastern bacterial isolates of clinical or environmental origin. Our goal in this study was to examine the genetic diversity of environmental strains isolated from commercially-produced oysters and in clinical strains of known pathogenicity in northeastern United States. We conducted analyses of a total of eighty-three strains of V. vulnificus, including 18 clinical strains known to be pathogenic. A polyphasic, molecular-typing approach was carried out, based upon established biotypes, vcg, CPS, 16S rRNA types and three other genes possibly associated with virulence (arylsulfatase A, mtlABC, and nanA). An established Multi Locus Sequence Typing (MLST) method was also performed. Phylogenetic analyses of these markers and MLST results produced similar patterns of clustering of strains into two main lineages (we categorized as 'LI' and 'LII'), with clinical and environmental strains clustering together in both lineages. Lineage LII was comprised primarily but not entirely of clinical bacterial isolates. Putative virulence markers were present in both clinical and environmental strains. These results suggest that some northeastern environmental strains of V. vulnificus are phylogenetically close to clinical strains and probably are capable of virulence. Further studies are necessary to assess the risk of human illness from consuming raw oysters harvested in the northeastern US.

Detection of qnrVC6, within a new genetic context, in a NDM-1-producing Citrobacter freundii clinical isolate from Uruguay.

PubMed

Bado, Inés; Ezdra, Romina Papa; Cordeiro, Nicolás; Outeda, Matilde; Caiata, Leticia; García-Fulgueiras, Virginia; Seija, Verónica; Vignoli, Rafael

2018-03-08

The objective of the present study was to characterise the mechanisms underlying quinolone and oxyimino-cephalosporin resistance in a Citrobacter freundii clinical isolate obtained from the ICU in Uruguay's University Hospital. Citrobacter freundii strain CF638 was isolated from a urine culture. Identification and susceptibility testing were performed using the VITEK ® 2 system, and MIC determination and disc diffusion assay, respectively. Resistance genes and mobile genetic elements were identified, by PCR and sequencing. Plasmid transfer was assessed by conjugation; plasmid, size was estimated by treatment with S1 and PFGE. Plasmid incompatibility, group and toxin-antitoxin systems were sought by PCR. Strain CF638 showed a multi-drug resistant profile, including, resistance to carbapenemes and quinolones. Transconjugant TcCF638, harbouring a ∼200 kb IncA/C plasmid, also showed resistance to all β-lactams, (except for aztreonam), and diminished susceptibility to ciprofloxacin. PCR, assays were positive for bla NDM-1 and qnrVC in CF638 and TcCF638. Two different class 1 integrons were detected, In127 and In907. In127, featured the genetic array: aadA2-ltr2. Conversely, complex In907 featured, two variable regions (VR); VR-1 consisted of aadB-bla OXA-10 -aadA1cc, whereas, VR-2, featured a gene qnrVC6 108 bp downstream from the ISCR1 and 45 bp, upstream from the qacEΔ1. Expression of qnrVC6 would be on account of a, putative promoter region, detected using the Neural Network Promoter, Prediction program. To the best of our knowledge this constitutes the first report of a qnrVC gene within a complex class 1 integron, and the first report as well of the occurrence of such gene in an NDM-1-producing enterobacterial clinical isolate. Copyright © 2018. Published by Elsevier Ltd.

Characterization of AmpC, CTX-M and MBLs types of β-lactamases in clinical isolates of Klebsiella pneumoniae and Escherichia coli producing Extended Spectrum β-lactamases in Kerman, Iran

PubMed Central

Mansouri, Shahla; Kalantar Neyestanaki, Davood; Shokoohi, Mostafa; Halimi, Shahnaz; Beigverdi, Reza; Rezagholezadeh, Fereshteh; Hashemi, Ali

2014-01-01

Background: Extended spectrum β-lactamases (ESBLs) and AmpC β-lactamases enzyme are major sources of resistance to β-lactam antibiotics especially in Enterobacteriaceae such as Escherichia coli and Klebsiella pneumoniae. Increasing frequency of the co-existence of ESBLs with AmpC-β-lactamases in bacteria is a serious threat for treating bacterial infections. Objectives: The aim of this study was to determine the presence of AmpC and CTX-M types of β-lactamases in clinical isolates of E. coli and K. pneumoniae producing ESBLs. Materials and Methods: Resistance to different antibiotics was determined using the standard disk diffusion method. ESBLs, MBLs and AmpC-β-lactamases were detected by the combination double disk test (CDDT) method and polymerase chain reaction (PCR) was used to determine blaCTX-M genes in the ESBLs and AmpC positive isolates. Results: The prevalence of ESBLs and AmpC-β-lactamase producer isolates was 181 (43.8%) and 133 (37.2%), respectively. The prevalence of blaCTX-M among isolates was 61 (14.7%). Conclusions: Outbreak of isolates co-expressing AmpC-β-lactamases and ESBLs can cause serious problems in the future, regarding the treatment of infections caused by these common enteric pathogens. PMID:25147671

Identification and Pathogenic Potential of Clinical Bacillus and Paenibacillus Isolates

PubMed Central

Celandroni, Francesco; Salvetti, Sara; Gueye, Sokhna Aissatou; Mazzantini, Diletta; Lupetti, Antonella; Senesi, Sonia; Ghelardi, Emilia

2016-01-01

The soil-related Bacillus and Paenibacillus species have increasingly been implicated in various human diseases. Nevertheless, their identification still poses problems in the clinical microbiology laboratory and, with the exception of Bacillus anthracis and Bacillus cereus, little is known on their pathogenicity for humans. In this study, we evaluated the use of matrix-assisted laser desorption—ionization time of flight mass spectrometry (MALDI-TOF MS) in the identification of clinical isolates of these genera and conducted genotypic and phenotypic analyses to highlight specific virulence properties. Seventy-five clinical isolates were subjected to biochemical and MALDI-TOF MS identification. 16S rDNA sequencing and supplemental tests were used to solve any discrepancies or failures in the identification results. MALDI-TOF MS significantly outperformed classical biochemical testing for correct species identification and no misidentification was obtained. One third of the collected strains belonged to the B. cereus species, but also Bacillus pumilus and Bacillus subtilis were isolated at high rate. Antimicrobial susceptibility testing showed that all the B. cereus, B. licheniformis, B. simplex, B. mycoides, Paenibacillus glucanolyticus and Paenibacillus lautus isolates are resistant to penicillin. The evaluation of toxin/enzyme secretion, toxin-encoding genes, motility, and biofilm formation revealed that B. cereus displays the highest virulence potential. However, although generally considered nonpathogenic, most of the other species were shown to swim, swarm, produce biofilms, and secrete proteases that can have a role in bacterial virulence. In conclusion, MALDI-TOF MS appears useful for fast and accurate identification of Bacillus and Paenibacillus strains whose virulence properties make them of increasing clinical relevance. PMID:27031639

Clonality and Resistome analysis of KPC-producing Klebsiella pneumoniae strain isolated in Korea using whole genome sequencing.

PubMed

Lee, Yangsoon; Kim, Bong-Soo; Chun, Jongsik; Yong, Ji Hyun; Lee, Yeong Seon; Yoo, Jung Sik; Yong, Dongeun; Hong, Seong Geun; D'Souza, Roshan; Thomson, Kenneth S; Lee, Kyungwon; Chong, Yunsop

2014-01-01

We analyzed the whole genome sequence and resistome of the outbreak Klebsiella pneumoniae strain MP14 and compared it with those of K. pneumoniae carbapenemase- (KPC-) producing isolates that showed high similarity in the NCBI genome database. A KPC-2-producing multidrug-resistant (MDR) K. pneumoniae clinical isolate was obtained from a patient admitted to a Korean hospital in 2011. The strain MP14 was resistant to all tested β-lactams including monobactam, amikacin, levofloxacin, and cotrimoxazole, but susceptible to tigecycline and colistin. Resistome analysis showed the presence of β-lactamase genes including bla KPC-2, bla SHV-11, bla TEM-169, and bla OXA-9. MP14 also possessed aac(6'-)Ib, aadA2, and aph(3'-)Ia as aminoglycoside resistance-encoding genes, mph(A) for macrolides, oqxA and oqxB for quinolone, catA1 for phenicol, sul1 for sulfonamide, and dfrA12 for trimethoprim. Both SNP tree and cgMLST analysis showed the close relatedness with the KPC producers (KPNIH strains) isolated from an outbreak in the USA and colistin-resistant strains isolated in Italy. The plasmid-scaffold genes in plasmids pKpQil, pKpQil-IT, pKPN3, or pKPN-IT were identified in MP14, KPNIH, and Italian strains. The KPC-2-producing MDR K. pneumoniae ST258 stain isolated in Korea was highly clonally related with MDR K. pneumoniae strains from the USA and Italy. Global spread of KPC-producing K. pneumoniae is a worrying phenomenon.

Genetic diversity of Bacillus sp producers of amylase isolated from the soil.

PubMed

Xavier, A R E O; Lima, E R; Oliveira, A M E; Cardoso, L; Santos, J; Cangussu, C H C; Leite, L N; Quirino, M C L; Júnior, I G C; Oliveira, D A; Xavier, M A S

2017-09-27

The microorganisms are the best source of extracellular enzymes since they allow an economical technology with low-resource consumption compared to animals and plants. The amylases are among the most important enzymes being the genus Bacillus one of the most investigated due to its ability to produce this enzyme. The objective of this study was to isolate and analyze the genetic diversity among bacteria of the genus Bacillus sp producer of amylase originated from the soil. To this end, soil samples were collected and submitted to the condition of extreme temperature. The serial dilution procedure followed by seeding on solid medium containing starch was used for isolation of strains that produce amylase. The microorganisms isolated were subjected to standard morphological methods for presumptive identification of the genus Bacillus. The PCR assay with the universal genetic marker 16S rDNA was used for confirmation of bacterial strain. All the 10 isolates presumptively identified as bacteria amplified a fragment of 370 bp corresponding to the 16S rDNA gene. The enzymatic activity was expressed as an enzymatic index (EI), after 24 h of incubation. All isolate producers of amylase exhibited EI ≥ 2.0. The determination of the genetic profile and the clonal relationship among the isolates were performed by the method of ERIC-PCR polymorphism. The isolates of Bacillus spp were divided into 2 groups (I and II). Through this method, the discriminatory capacity of this analysis of polymorphisms was verified in differing producer strains from those not producing amylase.

Evaluation of Antioxidant Activity and Growth Control Properties of Nonoscale Structure Produced from Aloe vera var. littoralis Extract on Clinical Isolates of Salmonella

PubMed Central

Hosseiny, Hossein

2017-01-01

The aim of the study was to examine antibacterial properties of microemulsion structure produced from Aloe vera var. littoralis extract as a new tool of nanoscale drug-like materials. Aloe vera var. littoralis (A. littoralis) extract was prepared by distillation method. A nonocarrier structure in the microemulsion system was prepared from the extract. Serial concentrations were prepared from 8 mg/mL extract and the nonocarrier containing 0.1 mg/mL pure extract and were evaluated by a disk diffusion method for 35 Salmonella clinical isolates. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by microbroth dilution assay using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) method by an enzyme-linked immunosorbent assay(ELISA) Microplate Reader apparatus. Antioxidant activity of the extract was determined by measuring the ferric reducing ability of plasma (FRAP) assay. From 35 clinical isolates of Salmonella, 17 isolates—including resistant isolates of S.E.1103 and S.E.49—had a zone of inhibition (ZI) of 7 to 32 mm in 0.007 mg/mL of the extract. S.E.76 isolate exposed to 30 µg/mL ceftazidime disk had a ZI of 12 mm but had 10 mm in 7µg/mL of A. littoralis extract. The inhibitory effect of a nanocarrier at a concentration of 25 µg/mL by 20 mm ZI was comparable by the ceftazidime (30 µg/mL) effect. MIC50 was 0.25 mg/mL and MBC50 was 0.5 mg/mL by MTT method for the extract. It was shown that A.littoralis extract had antioxidant activity of 31.67 µM/mg that could be increased based on concentration. It was concluded that the nanocarrier had a significant effect on the studied isolates in comparison with ordinary antibiotics and had potential for use as a natural antioxidant and antimicrobial material in complementary medicine. PMID:28758958

Molecular epidemiology of penicillinase-producing Neisseria gonorrhoeae isolates in France.

PubMed

Micaëlo, M; Goubard, A; La Ruche, G; Denamur, E; Tenaillon, O; Cambau, E; Jacquier, H; Bercot, B

2017-12-01

Characterizing the molecular epidemiology of antibiotic resistance is crucial for a better understanding of the evolution and spread of resistance in Neisseria gonorrhoeae. Here, we examine the molecular epidemiology of penicillinase-producing N. gonorrhoeae (PPNG) isolates in France. We investigated 176 PPNG isolates collected between 2010 and 2012 by the National Reference Centre in France. Genotyping was performed using the NG-MAST technique, bla TEM genes were Sanger-sequenced, and plasmids were characterized by PCR-typing. We revealed the existence of four major clusters representing about one-third of PPNG circulating in France. These clusters were related to ST1479 (18/176, 10.2%), to ST1582 (15/176, 8.5%), to ST8922 (10/176, 5.6%), and to ST1285 (9/176, 5.1%). Wild-type TEM-1 was identified in 151 (151/176, 85.8%) PPNG isolates, and TEM-1 variants were mostly represented by the M182T mutation (14/176, 8%), followed by P14S/L (8/176, 4.5%), G228S (2/176, 1.1%), and Q269K (1/176, 0.6%). The bla TEM genes were carried by African (157/176, 89.2%), Asian (13/176, 7.4%), and Toronto/Rio (6/176, 3.4%) plasmids. The M182T variants were found in various genetic backgrounds, whereas the P14S variants were disseminated clonally. The G228S and Q269K variants belong to one of the four major clusters of PPNG, which suggests a recent de novo emergence of these mutations. Our results show that approximately one-third of the penicillinase-producing N. gonorrhoeae isolates in France belong to one of four major clusters and that the spread of the different TEM variants is associated with distinct patterns of molecular epidemiology. Copyright © 2017 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Microbiological characterisation of Burkholderia cepacia isolates from cystic fibrosis patients: investigation of the exopolysaccharides produced.

PubMed

Lagatolla, Cristina; Skerlavaj, Silvia; Dolzani, Lucilla; Tonin, Enrico A; Monti Bragadin, Carlo; Bosco, Marco; Rizzo, Roberto; Giglio, Luisella; Cescutti, Paola

2002-03-19

Eleven strains of Burkholderia cepacia were isolated directly from clinical specimens: 10 from sputum of cystic fibrosis patients, and one from a vaginal swab. They were biochemically identified using API20NE and confirmed by a PCR-based assay. The genomovar characterisation obtained by specific PCR amplification revealed seven strains belonging to genomovar I, three belonging to genomovar IIIA and one belonging to genomovar IV. All isolates were also typed by ribotyping and random amplification of polymorphic DNA analysis. Some of the characterised strains were examined for the ability to produce exopolysaccharides, with the aim of correlating the genomovar with the exopolysaccharide structure. The polysaccharides were analysed by means of methylation analysis and 1H-NMR spectroscopy in order to determine structural similarities. It was shown that different strains are capable of producing chemically different polysaccharides.

Characterization of OXA-48-like-producing Enterobacteriaceae isolated from river water in Algeria.

PubMed

Tafoukt, Rima; Touati, Abdelaziz; Leangapichart, Thongpan; Bakour, Sofiane; Rolain, Jean-Marc

2017-09-01

The spread of carbapenemase-producing Enterobacteriaceae (CPE) is a significant problem for healthcare worldwide. The prevalence of carbapenem-resistant Enterobacteriaceae (CPE) in water environments in Algeria are unknown. The aim of this study was to screen for the presence of CPE isolates in the Soummam River in Bejaia, Algeria. Isolates of Enterobacteriaceae recovered from twelve samples of river water and showing reduced susceptibility to carbapenems were included in this study. The isolates were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Isolates were subjected to antimicrobial susceptibility testing and the modified Carba NP test. Carbapenemase and extended-spectrum β-lactamase (ESBL) determinants were studied by PCR amplification and sequencing. The clonal relatedness between isolates was studied by Multilocus Sequence Typing (MLST) method. A total of 20 carbapenem-resistant Enterobacteriaceae strains were included in this study, identified as Escherichia coli (n = 12), Klebsiella pneumoniae (n = 3), Raoultella ornithinolytica (n = 3), Citrobacter freundii (n = 1) and Citrobacter braakii (n = 1). Carbapenemase genes identified in this study included bla OXA-48 , observed in 17 isolates (9 E. coli, 3 K. pneumoniae, 3 R. ornithinolytica, 1 C. freundii and 1 C. braakii), and bla OXA-244 , a variant of bla OXA-48 , was found in three E. coli isolates. MLST showed that 12 E. coli strains belonged to six different sequence types (ST559, ST38, ST212, ST3541, 1972 and ST2142), and we identified three different STs in K. pneumoniae isolates, including ST133, ST2055, and a new sequence type: ST2192. This study showed the presence of OXA-48-like-producing Enterobacteriaceae in water environments and highlighted the potential role of aquatic environments as reservoirs of clinically relevant antimicrobial-resistant bacteria, with the potential to spread throughout the community. Copyright

Diversity of β-lactamases produced by imipenem resistant, Pseudomonas aeruginosa isolates from the bloodstream.

PubMed

Najar Peerayeh, Shahin; Pirhajati Mahabadi, Rahim; Pakbaten Toupkanlou, Sanaz; Siadat, Seyed Davar

2014-11-01

The emergence of imipenem non-susceptible Pseudomonas aeruginosa isolates is a matter of great concern because these isolates can become resistant to all available antibiotics. This study conducted to characterize β-lactamase genes in imipenem resistant P. aeruginosa isolates from bloodstream. 56 non-duplicate clinical isolates of P. aeruginosa were collected in Tehran hospitals. Antibacterial susceptibility was determined by disk diffusion and MIC methods. ESBL and MBL production was confirmed by combined disk. β-Lactamase classes A, B and D genes were identified by PCR. Seventeen (30.3%) isolates were imipenem resistant for which 16 isolates simultaneously were resistant to all tested antibiotics. While among 39 imipenem susceptible isolates, only two isolates were resistant to all tested antibiotics. In imipenem resistant isolates, blaTEM, blaSHV and blaOXA-10 were found in 41.1% of isolates and blaVIM, blaIMP and blaPER were identified in 47%, 11.7% and 5.8% of isolates respectively, while in imipenem susceptible isolates, blaTEM, blaSHV and blaOXA-10 were determined in 2.5%, 7.6% and 33.3% of isolates, respectively. The imipenem resistant isolates had been recovered mostly (67.7%) from patients in the Burn hospital. The result of this study indicated the emergence of multidrug resistant MBL and non-MBL producing P. aeruginosa, particularly in the Burn hospital and blaVIM was dominant β-lactamase genes in imipenem resistant isolates. The isolation of carrier patients may lead to prevent a further dissemination. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

Communication between hospitals and isolated aboriginal community health clinics.

PubMed

Mackenzie, G; Currie, B J

1999-04-01

This study described the communication dynamics, identified problems and recommended changes to improve patient follow-up and communication between Royal Darwin Hospital (RDH) and isolated Aboriginal community health clinics (CHC) in the Northern Territory (NT). In 1995, staff interviews were conducted and an audit of isolated Aboriginal patients' RDH discharge summaries (DS). Eighteen per cent of RDH DSs never arrived in CHCs. DSs were often prepared late and more likely to be in CHC records if written on time and if the referral source was specified. Interviews revealed discontent between CHCs and RDH regarding: communication, DS documentation, the supply of discharge medication, as well as different hospital and community perceptions of Aboriginies' reliability to carry a DS and CHC desire for patients to be given DSs at discharge. Aboriginal patients should be given a DS at discharge and resident medical officers should be educated as to the function and importance of the DS. In 18 months following this study, RDH appointed unit-based Aboriginal health workers and a policy was produced for written communication between hospital and CHCs, as well as a discharge planning manual for Aboriginal communities. Projects investigating communication between hospitals and isolated Aboriginal clinics and patient follow-up may result in significant policy changes concerning these processes.

Detection of the frequency of PER-1 type extended-spectrum β-lactamase-producing Acinetobacter baumannii clinical isolates in Turkey: a multicenter study.

PubMed

Aşik, Gülşah; Özdemir, Mehmet; Kurtoğlu, Muhammet Güzel; Yağci, Server; Öksüz, Lütfiye; Gül, Mustafa; Koçoğlu, Mücahide Esra; Sesli Çetin, Emel; Seyrek, Adnan; Berktaş, Mustafa; Ayyildiz, Ahmet; Çiftci, İhsan Hakkı

2014-01-01

β-Lactamases are an important resistance mechanism in Acinetobacter baumannii. Pseudomonas extended-resistance (PER-1) type β-lactamase-producing strains have been reported from various geographic locations; however, PER-1 type β-lactamases from Turkish hospitals have not been investigated extensively. The aim of this study was to determine the prevalence of PER-1 type β-lactamases in A. baumannii isolates in various regions of Turkey. A total of 763 clinical A. baumannii isolates were collected from 9 university hospitals and 2 state hospitals between 2008 and 2011. Molecular amplification of the OXA-51 gene from the A. baumannii genome was performed in order to verify identification of the species. Real-time polymerase chain reaction was used to detect blaPER-1 genes. PER-1 was detected in 24.6% of the isolates. The annual frequencies of the PER-1 enzyme were detected as 52.2%, 35.9%, and 8.3% in 2008, 2009, and 2010, respectively. PER-1 prevalence decreased gradually over time. The differences observed in PER-1 prevalence among the regions of Turkey were statistically significant (chi-square test; P < 0.001). These data demonstrate that the frequency of detection of PER-1 type β-lactamases in A. baumannii species has decreased in Turkey. However, the increased carbapenem resistance, together with multidrug resistance, has created a worrisome situation regarding this pathogen.

Expanded spectrum β-lactamase producing Escherichia coli isolated from chickens with colibacillosis in Egypt.

PubMed

El-Shazly, D A; Nasef, S A; Mahmoud, F F; Jonas, Daniel

2017-07-01

Throughout the world, expanded spectrum β-lactamases (ESBL) are increasing among clinical isolates of Enterobacteriaceae, both in humans and animals. Unfortunately, there is a paucity of data on ESBL or Ampicillin class C β-lactamase (AmpC) in Egypt, although antimicrobial consumption is high in this developing country. This study aims to characterize the resistance mechanisms to expanded spectrum cephalosporins among resistant veterinary Escherichia coli isolates in Egypt. We investigated 50 clinical multi-resistant E. coli strains isolated from 20 chicken farms for production of ESBL or AmpC. Antibiotic susceptibility was tested by Clinical and Laboratory Standards Institute (CLSI) disk diffusion and ESBL confirmatory tests. PCR and sequencing were performed to screen for plasmid mediated ESBL genes and genes encoding AmpC β-lactamases. All the isolates were phylogentically classified, investigated for harboring class 1 integrons, and genotyped by amplified fragment length polymorphism (AFLP). Three strains showed ESBL and 6 strains AmpC phenotypic patterns, respectively, with confirmed ESBL genes of blaTEM-57, blaSHV-12, blaCTX-M-14, and blaCMY-2 for AmpC producing strains. All ESBL strains belonged to phylogroup D with different clones isolated from different flocks, while most of the AmpC strains belonged to phylogroup B1 (4/6) and were assigned to the same genotype distributed in 2 different farms. Class 1 integrons were disseminated in 60% of all tested strains and in 100% of ESBL and AmpC strains. These results highlight the antimicrobial resistance problem in Egypt, caused in all probability by unwise use of antimicrobials in animal husbandry. The results call for a nationwide surveillance program to monitor antimicrobial resistance. © 2017 Poultry Science Association Inc.

Alternative methodology for isolation of biosurfactant-producing bacteria.

PubMed

Krepsky, N; Da Silva, F S; Fontana, L F; Crapez, M A C

2007-02-01

Wide biosurfactant application on biorremediation is limited by its high production cost. The search for cheaper biossurfactant production alternatives has guided our study. The use of selective media containing sucrose (10 g x L(-1)) and Arabian Light oil (2 g x L(-1)) as carbon sources showed to be effective to screen and maintain biosurfactant-producing consortia isolated from mangrove hydrocarbon-contaminated sediment. The biosurfactant production was assayed by kerosene, gasoline and Arabian Light Emulsification activity and the bacterial growth curve was determined by bacterial quantification. The parameters analyzed for biosurfactant production were the growth curve, salinity concentration, flask shape and oxygenation. All bacteria consortia screened were able to emulsify the petroleum derivatives tested. Biosurfactant production increased according to the incubation time; however the type of emulsification (non-aqueous phase or aqueous phase) did not change with time but with the compound tested. The methodology was able to isolate biosurfactant-producing consortia from superficial mangrove sediment contaminated by petroleum hydrocarbons and was recommended for selection of biosurfactant producing bacteria in tropical countries with low financial resources.

An in vitro biofilm model to examine the effect of antibiotic ointments on biofilms produced by burn wound bacterial isolates.

PubMed

Hammond, Adrienne A; Miller, Kyle G; Kruczek, Cassandra J; Dertien, Janet; Colmer-Hamood, Jane A; Griswold, John A; Horswill, Alexander R; Hamood, Abdul N

2011-03-01

Topical treatment of burn wounds is essential as reduced blood supply in the burned tissues restricts the effect of systemic antibiotics. On the burn surface, microorganisms exist within a complex structure termed a biofilm, which enhances bacterial resistance to antimicrobial agents significantly. Since bacteria differ in their ability to develop biofilms, the susceptibility of these biofilms to topically applied antibiotics varies, making it essential to identify which topical antibiotics efficiently disrupt or prevent biofilms produced by these pathogens. Yet, a simple in vitro assay to compare the susceptibility of biofilms produced by burn wound isolates to different topical antibiotics has not been reported. Biofilms were developed by inoculating cellulose disks on agar plates with burn wound isolates and incubating for 24h. The biofilms were then covered for 24h with untreated gauze or gauze coated with antibiotic ointment and remaining microorganisms were quantified and visualized microscopically. Mupirocin and triple antibiotic ointments significantly reduced biofilms produced by the Staphylococcus aureus and Pseudomonas aeruginosa burn wound isolates tested, as did gentamicin ointment, with the exception of one P. aeruginosa clinical isolate. The described assay is a practical and reproducible approach to identify topical antibiotics most effective in eliminating biofilms produced by burn wound isolates. Copyright © 2010 Elsevier Ltd and ISBI. All rights reserved.

Extended-spectrum beta-lactamase-producing bacteria isolated from hematologic patients in Manaus, State of Amazonas, Brazil

PubMed Central

Ferreira, Cristina Motta; Ferreira, William Antunes; Almeida, Nayanne Cristina Oliveira da Silva; Naveca, Felipe Gomes; Barbosa, Maria das Graças Vale

2011-01-01

Antibiotic therapy in hematologic patients, often weak and susceptible to a wide range of infections, particularly nosocomial infections derived from long hospitalization periods, is a challenging issue. This paper presents ESBL-producing strains isolated from such hematologic patients treated at the Amazon Hematology and Hemotherapy Foundation (HEMOAM) in the Brazilian Amazon Region to identify the ESBL genes carried by them as well as the susceptibility to 11 antimicrobial agents using the E-test method. A total of 146 clinical samples were obtained from July 2007 to August 2008, when 17 gram-negative strains were isolated in our institution. The most frequent isolates confirmed by biochemical tests and 16S rRNA sequencing were E. coli (8/17), Serratia spp. (3/17) and B.cepacia (2/17). All gram-negative strains were tested for extended-spectrum-beta-lactamases (ESBLs), where: (12/17) strains carried ESBL; among these, (8/12) isolates carried blaTEM, blaCTX-M, blaOXA , blaSHV genes, (1/12) blaTEM gene and (3/12) blaTEM, blaCTX-M, blaOXA genes. Antibiotic resistance was found in (15/17) of the isolates for tetracycline, (12/17) for ciprofloxacin, (1/17) resistance for cefoxitin and chloramphenicol, (1/17) for amikacin and (3/17) cefepime. This research showed the presence of gram-negative ESBL-producing bacteria infecting hematologic patients in HEMOAM. These strains carried the blaTEM, blaSHV, blaCTX-M and blaOXA genes and were resistant to different antibiotics used in the treatment. This finding was based on a period of 13 months, during which clinical samples from specific populations were obtained. Therefore, caution is required when generalizing the results that must be based on posological orientations and new breakpoints for disk diffusion and microdilution published by CLSI 2010. PMID:24031725

Molecular and clinical characterization of plasmid-mediated AmpC β-lactamase-producing Escherichia coli bacteraemia: a comparison with extended-spectrum β-lactamase-producing and non-resistant E. coli bacteraemia.

PubMed

Matsumura, Y; Nagao, M; Iguchi, M; Yagi, T; Komori, T; Fujita, N; Yamamoto, M; Matsushima, A; Takakura, S; Ichiyama, S

2013-02-01

Plasmid-mediated AmpC β-lactamase-producing Escherichia coli (AmpC-E) bacteraemia was characterized by comparison with bacteraemia caused by extended-spectrum β-lactamase (ESBL)-producing E. coli (ESBL-E) and non-resistant E. coli (NR-E) in the era of the worldwide spread of the CTX-M-15-producing O25b-ST131-B2 clone. Of 706 bloodstream E. coli isolates collected between 2005 and 2010 in three Japanese university hospitals, 111 ESBL screening-positive isolates were analysed for AmpC and ESBL genes by PCR. A case-control study was performed in which the cases consisted of all of the patients with AmpC-E bacteraemia. Phylogenetic groups, sequence types and O25b serotype were determined. Twenty-seven AmpC-E isolates (26 of which were of the CMY-2 type) were identified, and 54 ESBL-E and 54 NR-E isolates were selected for the controls. Nineteen AmpC-E isolates were also positive for ESBL. CTX-M-14 was the most prevalent ESBL type among both the AmpC-E and ESBL-E isolates. The O25b-ST131-B2 clone was the most prevalent among the ESBL-E isolates (26%) and the second most prevalent among the NR-E isolates (13%), but only one O25b-ST131-B2 clone was found among the AmpC-E isolates. Twenty-three different sequence types were identified among the AmpC-E isolates. When compared with bacteraemia with ESBL-E, previous isolation of multidrug-resistant bacteria and intravascular catheterization were independently associated with a lower risk for AmpC-E. When compared with NR-E bacteraemia, prior use of antibiotics was the only significant risk factor for AmpC-E. Unlike the spread of the O25b-ST131-B2 clone between ESBL-E and NR-E, the AmpC-E isolates were not dominated by any specific clone. © 2012 The Authors. Clinical Microbiology and Infection © 2012 European Society of Clinical Microbiology and Infectious Diseases.

Potentiating antibiotics in drug-resistant clinical isolates via stimuli-activated superoxide generation.

PubMed

Courtney, Colleen M; Goodman, Samuel M; Nagy, Toni A; Levy, Max; Bhusal, Pallavi; Madinger, Nancy E; Detweiler, Corrella S; Nagpal, Prashant; Chatterjee, Anushree

2017-10-01

The rise of multidrug-resistant (MDR) bacteria is a growing concern to global health and is exacerbated by the lack of new antibiotics. To treat already pervasive MDR infections, new classes of antibiotics or antibiotic adjuvants are needed. Reactive oxygen species (ROS) have been shown to play a role during antibacterial action; however, it is not yet understood whether ROS contribute directly to or are an outcome of bacterial lethality caused by antibiotics. We show that a light-activated nanoparticle, designed to produce tunable flux of specific ROS, superoxide, potentiates the activity of antibiotics in clinical MDR isolates of Escherichia coli , Salmonella enterica , and Klebsiella pneumoniae . Despite the high degree of antibiotic resistance in these isolates, we observed a synergistic interaction between both bactericidal and bacteriostatic antibiotics with varied mechanisms of action and our superoxide-producing nanoparticles in more than 75% of combinations. As a result of this potentiation, the effective antibiotic concentration of the clinical isolates was reduced up to 1000-fold below their respective sensitive/resistant breakpoint. Further, superoxide-generating nanoparticles in combination with ciprofloxacin reduced bacterial load in epithelial cells infected with S. enterica serovar Typhimurium and increased Caenorhabditis elegans survival upon infection with S. enterica serovar Enteriditis, compared to antibiotic alone. This demonstration highlights the ability to engineer superoxide generation to potentiate antibiotic activity and combat highly drug-resistant bacterial pathogens.

[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.

SlpE is a calcium-dependent cytotoxic metalloprotease associated with clinical isolates of Serratia marcescens.

PubMed

Stella, Nicholas A; Callaghan, Jake D; Zhang, Liang; Brothers, Kimberly M; Kowalski, Regis P; Huang, Jean J; Thibodeau, Patrick H; Shanks, Robert M Q

Serralysin-like proteases are found in a wide variety of bacteria. These metalloproteases are frequently implicated in virulence and are members of the widely conserved RTX-toxin family. We identified a serralysin-like protease in the genome of a clinical isolate of Serratia marcescens that is highly similar to the canonical serralysin protein, PrtS. This gene was named serralysin-like protease E, SlpE, and was found in the majority (67%) of tested clinical isolates, but was absent from most tested non-clinical isolates including the insect pathogen and reference S. marcescens strain Db11. Purified recombinant SlpE exhibited calcium-dependent protease activity similar to metalloproteases PrtS and SlpB. Induction of slpE in the low-protease-producing S. marcescens strain PIC3611 highly elevated extracellular protease activity, and extracellular secretion required the lipD type 1 secretion system gene. Transcription of slpE was highly reduced in an eepR transcription factor mutant. Mutation of the slpE gene in a highly proteolytic clinical isolate reduced its protease activity, and evidence suggests that SlpE confers cytotoxicity of S. marcescens to the A549 airway carcinoma cell line. Together, these data reveal SlpE to be an EepR-regulated cytotoxic metalloprotease associated with clinical isolates of an important opportunistic pathogen. Copyright © 2017 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Detection of Extended-Spectrum β-Lactamases in Clinical Isolates of Enterobacter cloacae and Enterobacter aerogenes

PubMed Central

Tzelepi, Eva; Giakkoupi, Panagiota; Sofianou, Danai; Loukova, Veneta; Kemeroglou, Anastassia; Tsakris, Athanassios

2000-01-01

The aim of the present study was to investigate the frequency of extended-spectrum β-lactamases (ESBLs) in a consecutive collection of clinical isolates of Enterobacter spp. The abilities of various screening methods to detect ESBLs in enterobacters were simultaneously tested. Among the 68 consecutive isolates (56 Enterobacter cloacae and 12 Enterobacter aerogenes isolates) that were analyzed for β-lactamase content, 21 (25 and 58%, respectively) possessed transferable ESBLs with pIs of 8.2 and phenotypic characteristics of SHV-type enzymes, 8 (14.3%) of the E. cloacae isolates produced a previously nondescribed, clavulanate-susceptible ESBL that exhibited a pI of 6.9 and that conferred a ceftazidime resistance phenotype on Escherichia coli transconjugants, and 2 E. cloacae isolates produced both of these enzymes. Among the total of 31 isolates that were considered ESBL producers, the Vitek ESBL detection test was positive for 2 (6.5%) strains, and the conventional double-disk synergy test (DDST) with amoxicillin-clavulanate and with expanded-spectrum cephalosporins and aztreonam was positive for 5 (16%) strains. Modifications of the DDST consisting of closer application of the disks (at 20 instead of 30 mm), the use of cefepime, and the use of both modifications increased the sensitivity of this test to 71, 61, and 90%, respectively. Of the 37 isolates for which isoelectric focusing failed to determine ESBLs, the Vitek test was false positive for 1 isolate and the various forms of DDSTs were false-positive for 3 isolates. PMID:10655342

Inhibition of Listeria monocytogenes biofilms by bacteriocin-producing bacteria isolated from mushroom substrate.

PubMed

Bolocan, A S; Pennone, V; O'Connor, P M; Coffey, A; Nicolau, A I; McAuliffe, O; Jordan, K

2017-01-01

This study was designed to investigate the ability of naturally occurring bacteria isolated from mushroom substrate to prevent biofilm formation by Listeria monocytogenes or to remove existing biofilms in mushroom production facilities. It is generally recognized that L. monocytogenes forms biofilms that can facilitate its survival in food-processing environments. Eleven bacteriocin-producing isolates were identified and the bacteriocins characterized based on heat and enzyme inactivation studies. Further characterization was undertaken by MALDI-TOF mass spectrometry, PCR and sequencing. Production of nisin Z (by Lactococcus lactis isolates), subtilomycin (by Bacillus subtilis isolates) and lichenicidin (by Bacillus licheniformis and Bacillus sonorensis isolates) was detected. In co-culture with L. monocytogenes, the bacteriocin-producing strains could prevent biofilm formation and reduce pre-formed biofilms. Mushroom substrate can be a source of bacteriocin-producing bacteria that can antagonize L. monocytogenes. The results highlight the potential of bacteriocin-producing strains from mushroom substrate to reduce L. monocytogenes biofilm in food production environments, contributing to a reduction in the risk of food contamination from the environment. © 2016 The Society for Applied Microbiology.

Detection of Metallo-β-Lactamase Producing Pseudomonas aeruginosa Isolated from Public and Private Hospitals in Baghdad, Iraq.

PubMed

Al-Charrakh, Alaa H; Al-Awadi, Salwa J; Mohammed, Ahmed S

2016-02-01

Metallo-β-lactamase (MBL) producing Pseudomonas aeruginosa has been reported to be an important nosocomial infection. Its intrinsic and acquired resistance to various antimicrobial agents and its ability to develop multidrug resistance imposes a serious therapeutic problem. Different clinical samples were collected from public and private hospitals in Baghdad city, Iraq. Bacterial identification was done using conventional cultural, biochemical tests, and VITEk 2 system. Minimum inhibitory concentration (MIC) testing was performed using VITEK 2 automated system. Each P. aeruginosa isolates showed resistance to Carbapenems (Imipenem and Meropenem) were subjected to Imipenem-EDTA combined disc synergy test (CDST) to investigate the production of MBL (confirmative test). The presence of bla-genes encoded IMP, VIM, and SPM-1 was detected by conventional PCR technique. A total of 75 P. aeruginosa isolates were isolated, 16 (21.3%) were able to grow on MacConkey agar supplemented with Meropenem 4mg/L (MMAC). The MIC of different antibiotics showed that 6 (37.5 %) isolates were Carbapenem resistant, MIC ≥16 µg/ml while 4 (25%) isolates appear to be MBL producer using CDST test. PCR assay revealed that 3 (50%), 1 (16.6%) of the carbapenem resistant isolates harbored blaIMP, blaSPM-1 genes, respectively. blaVIM gene was not detected in this study. The prevalence of multi-drug resistant P. aeruginosa isolates especially Carbapenem resistant bacteria was increased in Baghdad province. The blaIMP was the predominant among the MBLs genes in P. aeruginosa in this study.

Meropenem-Vaborbactam Tested against Contemporary Gram-Negative Isolates Collected Worldwide during 2014, Including Carbapenem-Resistant, KPC-Producing, Multidrug-Resistant, and Extensively Drug-Resistant Enterobacteriaceae.

PubMed

Castanheira, Mariana; Huband, Michael D; Mendes, Rodrigo E; Flamm, Robert K

2017-09-01

We evaluated the activity of meropenem-vaborbactam against contemporary nonfastidious Gram-negative clinical isolates, including Enterobacteriaceae isolates with resistance phenotypes and carbapenemase genotypes. Meropenem-vaborbactam (inhibitor at 8 μg/ml) and comparators were susceptibility tested by reference broth microdilution methods against 14,304 Gram-negative clinical isolates collected worldwide during 2014. Carbapenemase-encoding genes were screened by PCR and sequencing. Meropenem-vaborbactam (MIC 50/90 , ≤0.015/0.06 μg/ml) inhibited 99.1 and 99.3% of the 10,426 Enterobacteriaceae isolates tested at ≤1 and ≤2 μg/ml, respectively. Meropenem inhibited 97.3 and 97.7% of these isolates at the same concentrations. Against Enterobacteriaceae isolates displaying carbapenem-resistant Enterobacteriaceae (CRE) ( n = 265), multidrug-resistant (MDR) ( n = 1,210), and extensively drug-resistant (XDR) ( n = 161) phenotypes, meropenem-vaborbactam displayed MIC 50/90 values of 0.5/32, 0.03/1, and 0.5/32 μg/ml, respectively, whereas meropenem activities were 16/>32, 0.06/32, and 0.5/32 μg/ml, respectively. Among all geographic regions, the highest meropenem-vaborbactam activities were observed for CRE and MDR isolates from the United States (MIC 50/90 , 0.03/1 and 0.03/0.12 μg/ml, respectively). Meropenem-vaborbactam was very active against 135 KPC producers, and all isolates were inhibited by concentrations of ≤8 μg/ml (133 isolates by concentrations of ≤2 μg/ml). This combination had limited activity against isolates producing metallo-β-lactamases (including 25 NDM-1 and 16 VIM producers) and/or oxacillinases (27 OXA-48/OXA-163 producers) that were detected mainly in Asia-Pacific and some European countries. The activity of meropenem-vaborbactam was similar to that of meropenem alone against Pseudomonas aeruginosa , Acinetobacter spp., and Stenotrophomonas maltophilia Meropenem-vaborbactam was active against contemporary Enterobacteriaceae isolates

Mass Spectrometry and Multiplex Antigen Assays to Assess Microbial Quality and Toxin Production of Staphylococcus aureus Strains Isolated from Clinical and Food Samples

PubMed Central

Attien, Paul; Sina, Haziz; Moussaoui, Wardi; Zimmermann-Meisse, Gaëlle; Dadié, Thomas; Keller, Daniel; Riegel, Philippe; Edoh, Vincent; Kotchoni, Simeon O.; Djè, Marcellin; Prévost, Gilles

2014-01-01

The aim of our study was to investigate the microbial quality of meat products and on some clinical samples in Abidjan focused on Staphylococcus genus and the toxin production profile of Staphylococcus aureus (S. aureus) isolated. Bacteria were collected from 240 samples of three meat products sold in Abidjan and 180 samples issued from clinical infections. The strains were identified by both microbiological and MALDI-TOF-MS methods. The susceptibility to antibiotics was determined by the disc diffusion method. The production of Panton-Valentine Leukocidin, LukE/D, and epidermolysins was screened using radial gel immunodiffusion. The production of staphylococcal enterotoxins and TSST-1 was screened by a Bio-Plex Assay. We observed that 96/240 of meat samples and 32/180 of clinical samples were contaminated by Staphylococcus. Eleven species were isolated from meats and 4 from clinical samples. Forty-two S. aureus strains were isolated from ours samples. Variability of resistance was observed for most of the tested antibiotics but none of the strains displays a resistance to imipenem and quinolones. We observed that 89% of clinical S. aureus were resistant to methicillin against 58% for those issued from meat products. All S. aureus isolates issued from meat products produce epidermolysins whereas none of the clinical strains produced these toxins. The enterotoxins were variably produced by both clinical and meat product samples. PMID:24987686

Biofilm-Forming Abilities of Shiga Toxin-Producing Escherichia coli Isolates Associated with Human Infections

PubMed Central

Vogeleer, Philippe; Tremblay, Yannick D. N.; Jubelin, Grégory; Jacques, Mario

2015-01-01

Forming biofilms may be a survival strategy of Shiga toxin-producing Escherichia coli to enable it to persist in the environment and the food industry. Here, we evaluate and characterize the biofilm-forming ability of 39 isolates of Shiga toxin-producing Escherichia coli isolates recovered from human infection and belonging to seropathotypes A, B, or C. The presence and/or production of biofilm factors such as curli, cellulose, autotransporter, and fimbriae were investigated. The polymeric matrix of these biofilms was analyzed by confocal microscopy and by enzymatic digestion. Cell viability and matrix integrity were examined after sanitizer treatments. Isolates of the seropathotype A (O157:H7 and O157:NM), which have the highest relative incidence of human infection, had a greater ability to form biofilms than isolates of seropathotype B or C. Seropathotype A isolates were unique in their ability to produce cellulose and poly-N-acetylglucosamine. The integrity of the biofilms was dependent on proteins. Two autotransporter genes, ehaB and espP, and two fimbrial genes, z1538 and lpf2, were identified as potential genetic determinants for biofilm formation. Interestingly, the ability of several isolates from seropathotype A to form biofilms was associated with their ability to agglutinate yeast in a mannose-independent manner. We consider this an unidentified biofilm-associated factor produced by those isolates. Treatment with sanitizers reduced the viability of Shiga toxin-producing Escherichia coli but did not completely remove the biofilm matrix. Overall, our data indicate that biofilm formation could contribute to the persistence of Shiga toxin-producing Escherichia coli and specifically seropathotype A isolates in the environment. PMID:26712549

Biofilm-Forming Abilities of Shiga Toxin-Producing Escherichia coli Isolates Associated with Human Infections.

PubMed

Vogeleer, Philippe; Tremblay, Yannick D N; Jubelin, Grégory; Jacques, Mario; Harel, Josée

2015-12-28

Forming biofilms may be a survival strategy of Shiga toxin-producing Escherichia coli to enable it to persist in the environment and the food industry. Here, we evaluate and characterize the biofilm-forming ability of 39 isolates of Shiga toxin-producing Escherichia coli isolates recovered from human infection and belonging to seropathotypes A, B, or C. The presence and/or production of biofilm factors such as curli, cellulose, autotransporter, and fimbriae were investigated. The polymeric matrix of these biofilms was analyzed by confocal microscopy and by enzymatic digestion. Cell viability and matrix integrity were examined after sanitizer treatments. Isolates of the seropathotype A (O157:H7 and O157:NM), which have the highest relative incidence of human infection, had a greater ability to form biofilms than isolates of seropathotype B or C. Seropathotype A isolates were unique in their ability to produce cellulose and poly-N-acetylglucosamine. The integrity of the biofilms was dependent on proteins. Two autotransporter genes, ehaB and espP, and two fimbrial genes, z1538 and lpf2, were identified as potential genetic determinants for biofilm formation. Interestingly, the ability of several isolates from seropathotype A to form biofilms was associated with their ability to agglutinate yeast in a mannose-independent manner. We consider this an unidentified biofilm-associated factor produced by those isolates. Treatment with sanitizers reduced the viability of Shiga toxin-producing Escherichia coli but did not completely remove the biofilm matrix. Overall, our data indicate that biofilm formation could contribute to the persistence of Shiga toxin-producing Escherichia coli and specifically seropathotype A isolates in the environment. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Genetic diversity and virulence potential of shiga toxin-producing Escherichia coli O113:H21 strains isolated from clinical, environmental, and food sources.

PubMed

Feng, Peter C H; Delannoy, Sabine; Lacher, David W; Dos Santos, Luis Fernando; Beutin, Lothar; Fach, Patrick; Rivas, Marta; Hartland, Elizabeth L; Paton, Adrienne W; Guth, Beatriz E C

2014-08-01

Shiga toxin-producing Escherichia coli strains of serotype O113:H21 have caused severe human diseases, but they are unusual in that they do not produce adherence factors coded by the locus of enterocyte effacement. Here, a PCR microarray was used to characterize 65 O113:H21 strains isolated from the environment, food, and clinical infections from various countries. In comparison to the pathogenic strains that were implicated in hemolytic-uremic syndrome in Australia, there were no clear differences between the pathogens and the environmental strains with respect to the 41 genetic markers tested. Furthermore, all of the strains carried only Shiga toxin subtypes associated with human infections, suggesting that the environmental strains have the potential to cause disease. Most of the O113:H21 strains were closely related and belonged in the same clonal group (ST-223), but CRISPR analysis showed a great degree of genetic diversity among the O113:H21 strains. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Occurrence of killer Candida glabrata clinical isolates

PubMed Central

Arroyo-Helguera, O; Penas Alejandro, De Las; Irene, Castaño

2012-01-01

In this work we characterized the occurrence of killer activity in 64 Candida glabrata clinical isolates under different conditions. We found that only 6.25 % of the clinical isolates tested were positive for killer activity against a Saccharomyces cerevisiae W303 sensitive strain. Sensitivity of killer activity to different values of pH and temperatures was analyzed. We found that the killer activity presented by all isolates was resistant to every pH and temperature tested, although optimal activity was found at a range of pH values from 4 to 7 and at 37°C. We did not observe extrachromosomal genetic elements associated with killer activity in any of the positive C. glabrata isolates. The killer effect was due to a decrease in viability and DNA fragmentation in sensitive yeast. PMID:24031902

Comparative genomic analysis of Mycobacterium tuberculosis clinical isolates.

PubMed

Liu, Fei; Hu, Yongfei; Wang, Qi; Li, Hong Min; Gao, George F; Liu, Cui Hua; Zhu, Baoli

2014-06-13

Due to excessive antibiotic use, drug-resistant Mycobacterium tuberculosis has become a serious public health threat and a major obstacle to disease control in many countries. To better understand the evolution of drug-resistant M. tuberculosis strains, we performed whole genome sequencing for 7 M. tuberculosis clinical isolates with different antibiotic resistance profiles and conducted comparative genomic analysis of gene variations among them. We observed that all 7 M. tuberculosis clinical isolates with different levels of drug resistance harbored similar numbers of SNPs, ranging from 1409-1464. The numbers of insertion/deletions (Indels) identified in the 7 isolates were also similar, ranging from 56 to 101. A total of 39 types of mutations were identified in drug resistance-associated loci, including 14 previously reported ones and 25 newly identified ones. Sixteen of the identified large Indels spanned PE-PPE-PGRS genes, which represents a major source of antigenic variability. Aside from SNPs and Indels, a CRISPR locus with varied spacers was observed in all 7 clinical isolates, suggesting that they might play an important role in plasticity of the M. tuberculosis genome. The nucleotide diversity (Л value) and selection intensity (dN/dS value) of the whole genome sequences of the 7 isolates were similar. The dN/dS values were less than 1 for all 7 isolates (range from 0.608885 to 0.637365), supporting the notion that M. tuberculosis genomes undergo purifying selection. The Л values and dN/dS values were comparable between drug-susceptible and drug-resistant strains. In this study, we show that clinical M. tuberculosis isolates exhibit distinct variations in terms of the distribution of SNP, Indels, CRISPR-cas locus, as well as the nucleotide diversity and selection intensity, but there are no generalizable differences between drug-susceptible and drug-resistant isolates on the genomic scale. Our study provides evidence strengthening the notion that

A Bioreactor Method to Generate High-titer, Genetically Stable, Clinical-isolate Human Cytomegalovirus.

PubMed

Saykally, Victoria R; Rast, Luke I; Sasaki, Jeff; Jung, Seung-Yong; Bolovan-Fritts, Cynthia; Weinberger, Leor S

2017-11-05

Human cytomegalovirus (HCMV) infection is a major cause of morbidity and mortality in transplant patients and a leading cause of congenital birth defects (Saint Louis, 2016). Vaccination and therapeutic studies often require scalable cell culture production of wild type virus, represented by clinical isolates. Obtaining sufficient stocks of wild-type clinical HCMV is often labor intensive and inefficient due to low yield and genetic loss, presenting a barrier to studies of clinical isolates. Here we report a bioreactor method based on continuous infection, where retinal pigment epithelial (ARPE-19) cells adhered to microcarrier beads are infected in a bioreactor and used to produce high-titers of clinical isolate HCMV that maintain genetic integrity of key viral tropism factors and the viral genome. In this bioreactor, an end-stage infection can be maintained by regular addition of uninfected ARPE-19 cells, providing convenient preparation of 10 7 -10 8 pfu/ml of concentrated TB40/E IE2-EYFP stocks without daily cell passaging or trypsinization. Overall, this represents a 100-fold increase in gain of virus production of 100-times compared to conventional static-culture plates, while requiring 90% less handling time. Moreover, this continuous infection environment has the potential to monitor infection dynamics with applications for real-time tracking of viral evolution.

Genotypic and phenotypic profiles of Escherichia coli isolates belonging to clinical sequence type 131 (ST131), clinical non-ST131, and fecal non-ST131 lineages from India.

PubMed

Hussain, Arif; Ranjan, Amit; Nandanwar, Nishant; Babbar, Anshu; Jadhav, Savita; Ahmed, Niyaz

2014-12-01

In view of the epidemiological success of CTX-M-15-producing lineages of Escherichia coli and particularly of sequence type 131 (ST131), it is of significant interest to explore its prevalence in countries such as India and to determine if antibiotic resistance, virulence, metabolic potential, and/or the genetic architecture of the ST131 isolates differ from those of non-ST131 isolates. A collection of 126 E. coli isolates comprising 43 ST131 E. coli, 40 non-ST131 E. coli, and 43 fecal E. coli isolates collected from a tertiary care hospital in India was analyzed. These isolates were subjected to enterobacterial repetitive intergenic consensus (ERIC)-based fingerprinting, O typing, phylogenetic grouping, antibiotic sensitivity testing, and virulence and antimicrobial resistance gene (VAG) detection. Representative isolates from this collection were also analyzed by multilocus sequence typing (MLST), conjugation, metabolic profiling, biofilm production assay, and zebra fish lethality assay. All of the 43 ST131 E. coli isolates were exclusively associated with phylogenetic group B2 (100%), while most of the clinical non-ST131 and stool non-ST131 E. coli isolates were affiliated with the B2 (38%) and A (58%) phylogenetic groups, respectively. Significantly greater proportions of ST131 isolates (58%) than non-ST131 isolates (clinical and stool E. coli isolates, 5% each) were technically identified to be extraintestinal pathogenic E. coli (ExPEC). The clinical ST131, clinical non-ST131, and stool non-ST131 E. coli isolates exhibited high rates of multidrug resistance (95%, 91%, and 91%, respectively), extended-spectrum-β-lactamase (ESBL) production (86%, 83%, and 91%, respectively), and metallo-β-lactamase (MBL) production (28%, 33%, and 0%, respectively). CTX-M-15 was strongly linked with ESBL production in ST131 isolates (93%), whereas CTX-M-15 plus TEM were present in clinical and stool non-ST131 E. coli isolates. Using MLST, we confirmed the presence of two NDM-1

Characterisation of extended-spectrum β-lactamase and AmpC β-lactamase-producing Enterobacteriaceae isolated from companion animals in New Zealand.

PubMed

Karkaba, A; Grinberg, A; Benschop, J; Pleydell, E

2017-03-01

and AmpC-producing Enterobacteriaceae were associated with clinical infections in companion animals in New Zealand, and were often multidrug resistant. In this study, these organisms accounted for <5% of all Enterobacteriaceae isolated from infection sites by one laboratory network, but their prevalence among isolates resistant to amoxicillin-clavulanic acid was 61%. Therefore routine secondary testing for ESBL and AmpC production by Enterobacteriaceae that are resistant to amoxicillin-clavulanic acid in primary testing could improve the accuracy of definitive antimicrobial therapy in companion animals in New Zealand.

Emergence of VIM-4 metallo-β-lactamase-producing Klebsiella pneumoniae ST15 clone in the Clinical Centre University of Pécs, Hungary.

PubMed

Melegh, S; Kovács, K; Gám, T; Nyul, A; Patkó, B; Tóth, A; Damjanova, I; Mestyán, G

2014-01-01

Since November 2009 carbapenemase-producing Klebsiella pneumoniae isolates have been detected in increasing numbers at the Clinical Centre University of Pécs. Molecular typing was performed for 102 clinical isolates originating from different time periods and various departments of the Clinical Centre. Pulsed-field gel electrophoresis revealed the predominance of a single clone (101/102), identified as sequence type ST15. PCR and sequencing showed the presence of blaCTX-M-15 and blaVIM-4 genes. The blaVIM-4 was located on a class 1 integron designated In238b. To our knowledge, this is the first description of a blaVIM-4 gene in the predominant CTX-M-15 extended spectrum β-lactamase-producing Hungarian Epidemic Clone/ST15. © 2013 The Authors Clinical Microbiology and Infection © 2013 European Society of Clinical Microbiology and Infectious Diseases.

Proteolysis produced within biofilms of bacterial isolates from raw milk tankers.

PubMed

Teh, Koon Hoong; Flint, Steve; Palmer, Jon; Andrewes, Paul; Bremer, Phil; Lindsay, Denise

2012-06-15

In this study, six bacterial isolates that produced thermo-resistant enzymes isolated from the internal surfaces of raw milk tankers were evaluated for their ability to produce proteolysis within either single culture biofilms or co-culture biofilms. Biofilms were formed in an in vitro model system that simulated the upper internal surface of a raw milk tanker during a typical summer's day of milk collection in New Zealand. The bacterial isolates were further evaluated for their ability to form biofilms at 25, 30 and 37°C. Mutual and competitive effects were observed in some of the co-culture biofilms, with all isolates being able to form biofilms in either single culture or co-culture at the three temperatures. The proteolysis was also evaluated in both biofilms and corresponding planktonic cultures. The proteolysis per cell decreased as the temperature of incubation (20-37°C) increased. Furthermore, mutualistic interactions in terms of proteolysis were observed when cultures were grown as co-culture biofilms. This is the first study to show that proteolytic enzymes can be produced in biofilms on the internal surfaces of raw milk tankers. This has important implications for the cleaning and the temperature control of raw milk transport tankers. Copyright © 2012 Elsevier B.V. All rights reserved.

Prevalence of ESBL-producing Pseudomonas aeruginosa isolates in Warsaw, Poland, detected by various phenotypic and genotypic methods

PubMed Central

Róg, Patrycja; Smolińska-Król, Katarzyna; Ćmiel, Milena; Słoczyńska, Alicja; Patzer, Jan; Dzierżanowska, Danuta; Wolinowska, Renata; Starościak, Bohdan; Tyski, Stefan

2017-01-01

Knowledge of the prevalence of ESBL enzymes among P. aeruginosa strains compared to the Enterobacteraiceae family is limited. The phenotypic tests recommended by EUCAST for the detection of ESBL-producing Enterobacteriaceae are not always suited for P. aeruginosa strains. This is mainly due to the presence of other families of ESBLs in P. aeruginosa isolates more often than in Enterobacteriaceae, production of natural AmpC cephalosporinase and its overexpression, and co-production of metallo-β-lactamases. The aim of this study was to determine the occurrence of ESBLs in P. aeruginosa isolated from patients from hospitals in Warsaw, to evaluate the ESBL production of these isolates using currently available phenotypic tests, their modifications, multiplex PCR and molecular typing of ESBL-positive isolates by PFGE. Clinical isolates of P. aeruginosa were collected in 2000-2014 from four Warsaw hospitals. Based on the data obtained in this study, we suggest using three DDST methods with inhibitors, such as clavulanic acid, sulbactam and imipenem, to detect ESBL-producing P. aeruginosa strains. Depending on the appearance of the plates, we suggest a reduction in the distance between discs with antibiotics to 15 mm and the addition of boronic acid at 0.4 mg per disc. The analysed isolates carried genes encoding ESBL from the families VEB (69 isolates with VEB-9), GES (6 with GES-1, 1 GES-5, 5 GES-13 and 2 with GES-15), OXA-2 (12 with OXA-15, 1 OXA-141, 1 OXA-210, 1 OXA-543 and 1 with OXA-544) and OXA-10 (5 isolates with OXA-74 and one with OXA-142). The most important result of this study was the discovery of three new genes, blaGES-15, blaOXA-141 and blaOXA-142; their nucleotide sequences have been submitted to the NCBI GenBank. It is also very important to note that this is the first report on the epidemiological problem of VEB-9-producing bacterial strains, not only in Poland but also worldwide. PMID:28658322

Candida species biofilm and Candida albicans ALS3 polymorphisms in clinical isolates

PubMed Central

Bruder-Nascimento, Ariane; Camargo, Carlos Henrique; Mondelli, Alessandro Lia; Sugizaki, Maria Fátima; Sadatsune, Terue; Bagagli, Eduardo

2014-01-01

Over the last decades, there have been important changes in the epidemiology of Candida infections. In recent years, Candida species have emerged as important causes of invasive infections mainly among immunocompromised patients. This study analyzed Candida spp. isolates and compared the frequency and biofilm production of different species among the different sources of isolation: blood, urine, vulvovaginal secretions and peritoneal dialysis fluid. Biofilm production was quantified in 327 Candida isolates obtained from patients attended at a Brazilian tertiary public hospital (Botucatu, Sao Paulo). C. albicans ALS3 gene polymorphism was also evaluated by determining the number of repeated motifs in the central domain. Of the 198 total biofilm-positive isolates, 72 and 126 were considered as low and high biofilm producers, respectively. Biofilm production by C. albicans was significantly lower than that by non-albicans isolates and was most frequently observed in C. tropicalis. Biofilm production was more frequent among bloodstream isolates than other clinical sources, in urine, the isolates displayed a peculiar distribution by presenting two distinct peaks, one containing biofilm-negative isolates and the other containing isolates with intense biofilm production. The numbers of tandem-repeat copies per allele were not associated with biofilm production, suggesting the evolvement of other genetic determinants. PMID:25763043

Faecal carriage of extended-spectrum β-lactamase-producing and AmpC β-lactamase-producing bacteria among Danish army recruits.

PubMed

Hammerum, A M; Lester, C H; Jakobsen, L; Porsbo, L J

2011-04-01

During May and June 2008, 84 Danish army recruits were tested for faecal carriage of extended-spectrum β-lactamase (ESBL)-producing and AmpC β-lactamase-producing bacteria. Three ESBL-producing (CTX-M-14a) Escherichia coli isolates, two AmpC-producing (CMY-2) E. coli isolates and one AmpC-producing (CMY-34) Citrobacter freundii isolate were detected. Two of the CTX-M-14a E. coli isolates had similar pulsed-field gel electrophoresis and multilocus sequence typing profiles, indicating the same origin or transmission between the two army recruits. The bla(CTX-M-14a) genes were transferable to an E. coli recipient. These commensal bacteria therefore constitute a reservoir of resistance genes that can be transferred to other pathogenic bacteria in the intestine. © 2010 The Authors. Clinical Microbiology and Infection © 2010 European Society of Clinical Microbiology and Infectious Diseases.

[Isolation and characterization of vaginal lactobacilli producing hydrogen peroxide].

PubMed

Pashaian, M M; Oganesian, G G

2011-01-01

Isolation and characteristics of vaginal lactobacilli that actively generate H2O2 and have high antagonistic activity. Staphylococcus aureus 8956, Escherichia coli 8852, Klebsiella pneumoniae 8795 and Candida albicans 5646 were used as target-strains. Skim milk and MRS medium were used for lactobacilli isolation and cultivation. Antagonism was studied in complete agar and Saburo medium. Merckoquant peroxide test (Merck) stripes were used for the determination of H2O2. Antibacterial activity was determined by diffusion into agar. Specific culture growth rate was determined by conventional method, acidification of the culture medium--by pH-meter. 12 strains were isolated from vaginal smears of healthy women. These strains have an ability to ferment milk among which a highly active H2O2 producer was isolated and attributed to Lactobacillus delbrueckii by the results of 16S rRNA and alpha-subunit RNA polymerase gene sequence analysis (16S rDNA and rpoA genes are registered in GenBank, numbers HQ379171 and HQ379180 respectively). L. delbrueckii MH-10 bacterial cells were characterized by specific growth speed 1.26 per hour, reaching a maximum titer of 2 x 10(9) PFU/ml with lowering medium pH to 4.0. Under aerated conditions H2O2 concentration reached 100 microg/ml or more. L. delbrueckii MH-10 has high antibacterial activity against S. aureus, E. coli, K. pneumoniae. L. delbrueckii MH-10 isolate is an active H2O2 producer, has high growth speed and broad antibacterial activity spectrum, is a perspective candidate for the development of probiotic preparation for the prophylaxis and therapy of vaginoses.

Screening, identification and characterization of bacteriocins produced by wine-isolated LAB strains.

PubMed

Ndlovu, B; Schoeman, H; Franz, C M A P; du Toit, M

2015-04-01

To screen and identify wine-isolated LAB strains for bacteriocin production, and to identify and characterize bacteriocins. One hundred and fifty-five LAB strains isolated from South African red wines undergoing spontaneous malolactic fermentation were screened for bacteriocin production. Eight isolates were identified to be bacteriocin producers and were identified as Enterococcus faecium. All eight isolates had the same phenotypic and genotypic profiles. The peptides were preliminarily identified as enterocin P using mass spectrometry and further confirmed by PCR-amplifying enterocin P gene. The enterocin activity was inhibited by α-Chymotrypsin, papain and proteinase K treatments. It was heat stable at 37, 60, 80 and 100°C and showed activity over a broad pH range of 2-10. The production of the enterocin followed that of primary metabolite kinetics and, it showed bactericidal effect to some wine spoilage LAB strains. Our study identified the presence of the enterocin-producing Enterococcus in wine. The enterocin was heat stable; with broad pH range and bactericidal effects to sensitive strains. This is one of very few studies that isolated Enterococcus species from wine. It is, however, the first to report presence of bacteriocin-producing Enterococcus in wine fermentation. © 2015 The Society for Applied Microbiology.

[In-vitro activity of panipenem against clinical isolates in 2006].

PubMed

Yoshida, Sanae; Koga, Tetsufumi; Kakuta, Masayo; Kobayashi, Intetsu; Matsuzaki, Kaoru; Urabe, Eriko; Omika, Kaoru; Hasegawa, Miyuki; Sato, Yumie

2008-02-01

The antimicrobial activity of various antibiotics against clinical bacterial isolates recovered from patients with infectious diseases at the medical facilities in the Kanto region between March and September 2006 was evaluated. A total of 1030 clinical isolates were available for susceptibility tests: 420 aerobic Gram-positive organisms, 520 aerobic Gram-negative organisms, 30 anaerobic Gram-positive organisms and 60 anaerobic Gram-negative pathogens. Antimicrobial susceptibility data for Streptococcus pneumoniae and Haemophilus influenzae isolates from pediatric and adult patients were analyzed separately. Panipenem (PAPM), imipenem (IPM), meropenem (MEPM), biapenem (BIPM), doripenem (DRPM), cefozopran (CZOP), cefepime (CFPM), and sulbactam/cefoperazone (SBT/CPZ) were used as test antibiotics. PAPM, IPM and DRPM exhibited excellent in vitro antibacterial activities against methicillin-susceptible Staphylococcus, with all isolates exhibiting a MIC of < or =0.06 microg/mL. Against Streptococcus including penicillin-resistant S. pneumoniae, PAPM demonstrated the strongest antibacterial activity among the carbapenems with a MIC range of < or =0.06 to 0.12 microg/mL. Against Enterobacteriaceae, MEPM showed the strongest antibacterial activity, and PAPM had comparable activity to IPM. Against the extended-spectrum beta-lactamase producing Escherichia coli, Klebsiella species and Proteus species, the MICs for the cephems were high, however, those for the carbepenems were low. Against H. influenzae, PAPM had comparable activity to IPM. With respect to anaerobes, each of the carbapenems tested demonstrated almost the same strong antibacterial activity. In conclusion, 13 years has passed since PAPM was launched in 1993, PAPM still maintains potent antibacterial activity and is considered an effective antimicrobial agent for various types of infectious diseases.

Prevalence of extended-spectrum beta-lactamases-producing microorganisms in nosocomial patients and molecular characterization of the shv type isolates

PubMed Central

de Oliveira, Caio Fernando; Salla, Adenilde; Lara, Valéria Maria; Rieger, Alexandre; Horta, Jorge André; Alves, Sydney Hartz

2010-01-01

The emergence of Extended-Spectrum Beta-Lactamase (ESBL)-producing microorganisms in Brazilian hospitals is a challenge that concerns scientists, clinicians and healthcare institutions due to the serious risk they pose to confined patients. The goal of this study was the detection of ESBL production by clinical strains of Escherichia coli and Klebsiella sp. isolated from pus, urine and blood of patients at Hospital Universitário Santa Maria, Rio Grande Sul, RS, Brazil and the genotyping of the isolates based on bla SHV genes. The ESBL study was carried out using the Combined Disc Method, while Polymerase Chain Reaction (PCR) was used to study the bla SHV genes. Of the 90 tested isolates, 55 (61.1%) were identified as ESBL-producing by the combined disk method. The bla SHV genes were found in 67.8% of these microorganisms. K. pneumoniae predominated in the samples, presenting the highest frequency of positive results from the combined disk and PCR. PMID:24031491

Phenotypic characterization of enzymatic activity of clinical dermatophyte isolates from animals with and without skin lesions and humans.

PubMed

Gnat, Sebastian; Łagowski, Dominik; Nowakiewicz, Aneta; Zięba, Przemysław

2018-05-20

The pathogenesis of dermatophytoses is associated with the secretion of enzymes degrading the infected tissue components. Although many studies on enzymatic activity of dermatophytes have been conducted over the years, there have been no concrete proposals on construction of the profile of enzymes characteristic of individual species, genus, or ecological types of dermatophytes. The aim of this study was to assess the capability of clinical dermatophyte isolates from both symptomatic and asymptomatic animals and humans to produce different enzymes. Clinical isolates of 234 dermatophyte strains collected during routine examination of animal health were used in this study. The enzymatic production of keratinase, elastase, phospholipase, lipase, protease, DNase, and gelatinase as well as the haemolytic activity were evaluated using specific test media. The overall degree of enzymatic activity of the analysed clinical isolates of the dermatophytes was 67%. All tested clinical isolates of different species of dermatophytes showed keratinase activity and 96% additionally exhibited phospholipase activity. The weakest activity among the tested enzymes was demonstrated for elastase and gelatinase. 83% of the isolates of the dermatophytes showed haemolytic activity. Our data indicate that clinical isolates of dermatophytes from different species produce enzymes with different levels of activities. Profile of enzymes characteristic of individual species, genus, or ecological types of dermatophytes is possibly dependent upon factors related to the host. The relationship between each enzyme and the occurrence of skin lesions in animals and humans or asymptomatic animal carriers varies on whether the infection is caused by T. mentagrophytes, T. verrucosum, or M. canis. Interestingly, only keratinase seems to be correlated with the appearance of dermatophyte infections, irrespective of the pathogen species, and elastase is a characteristic enzyme for dermatophyte strains

Emergence of Salmonella genomic island 1 (SGI1) among Proteus mirabilis clinical isolates in Dijon, France.

PubMed

Siebor, Eliane; Neuwirth, Catherine

2013-08-01

Salmonella genomic island 1 (SGI1) is often encountered in antibiotic-resistant Salmonella enterica and exceptionally in Proteus mirabilis. We investigated the prevalence of SGI1-producing clinical isolates of P. mirabilis in our hospital (Dijon, France). A total of 57 strains of P. mirabilis resistant to amoxicillin and/or gentamicin and/or trimethoprim/sulfamethoxazole isolated from August 2011 to February 2012 as well as 9 extended-spectrum β-lactamase (ESBL)-producing P. mirabilis from our collection were tested for the presence of SGI1 by PCR. The complete SGI1 structure from positive isolates [backbone and multidrug resistance (MDR) region] was sequenced. SGI1 was detected in 7 isolates; 5 out of the 57 isolates collected during the study period (9%) and 2 out of the 9 ESBL-producing strains of our collection. The structures of the seven SGI1s were distinct. Three different backbones were identified: one identical to the SGI1 backbone from the epidemic Salmonella Typhimurium DT104, one with variations already described in SGI1-K from Salmonella Kentucky (deletion and insertion of IS1359 in the region spanning from S005 to S009) and one with a variation never detected before (deletion from S005 to S009). Six different MDR regions were identified: four simple variants containing resistance genes already described and two variants harbouring a very complex structure including regions derived from several transposons and IS26 elements with aphA1a never reported to date in SGI1. SGI1 variants are widely distributed among P. mirabilis clinical strains and might spread to other commensal Enterobacteriaceae. This would become a serious public health problem.

Serogroup, virulence, and molecular traits of Vibrio parahaemolyticus isolated from clinical and cockle sources in northeastern Thailand.

PubMed

Mala, Wanida; Alam, Munirul; Angkititrakul, Sunpetch; Wongwajana, Suwin; Lulitanond, Viraphong; Huttayananont, Sriwanna; Kaewkes, Wanlop; Faksri, Kiatichai; Chomvarin, Chariya

2016-04-01

Vibrio parahaemolyticus is responsible for seafood-borne gastroenteritis worldwide. Isolates of V. parahaemolyticus from clinical samples (n=74) and cockles (Anadara granosa) (n=74) in Thailand were analyzed by serotyping, determination of virulence and related marker genes present, response to antimicrobial agents, and genetic relatedness. Serological analysis revealed 31 different serotypes, 10 of which occurred among both clinical and cockle samples. The clinical isolates commonly included the pandemic serogroup O3:K6, while a few of the cockle isolates exhibited likely pandemic serovariants such as O3:KUT and O4:KUT, but not O3:K6. The pandemic (orf8 gene-positive) strains were more frequently found among clinical isolates (78.4%) than cockle isolates (28.4%) (p<0.001). Likewise, the virulence and related marker genes were more commonly detected among clinical than cockle isolates; i.e., tdh gene (93.2% versus 29.7%), vcrD2 (97.3% versus 23.0%), vopB2 (89.2% versus 13.5%), vopT (98.6% versus 36.5%) (all p<0.001) and trh (10.8% versus 1.4%) (p<0.05). Pulsed-field gel electrophoresis of NotI-digested genomic DNA of 41 randomly selected V. parahaemolyticus isolates representing different serotypes produced 33 pulsotypes that formed 5 different clusters (clonal complexes) (A-E) in a dendrogram. Vibrio parahaemolyticus O3:K6 and likely related pandemic serotypes were especially common among the numerous clinical isolates in cluster C, suggesting a close clonal link among many of these isolates. Most clinical and cockle isolates were resistant to ampicillin. This study indicates that O3:K6 and its likely serovariants based on the PFGE clusters, are causative agents. Seafoods such as cockles potentially serve as a source of virulent V. parahaemolyticus, but further work is required to identify possible additional sources. Copyright © 2016. Published by Elsevier B.V.

Screening and isolation of halophilic bacteria producing industrially important enzymes.

PubMed

Kumar, Sumit; Karan, Ram; Kapoor, Sanjay; S P, Singh; S K, Khare

2012-10-01

Halophiles are excellent sources of enzymes that are not only salt stable but also can withstand and carry out reactions efficiently under extreme conditions. The aim of the study was to isolate and study the diversity among halophilic bacteria producing enzymes of industrial value. Screening of halophiles from various saline habitats of India led to isolation of 108 halophilic bacteria producing industrially important hydrolases (amylases, lipases and proteases). Characterization of 21 potential isolates by morphological, biochemical and 16S rRNA gene analysis found them related to Marinobacter, Virgibacillus, Halobacillus, Geomicrobium, Chromohalobacter, Oceanobacillus, Bacillus, Halomonas and Staphylococcus genera. They belonged to moderately halophilic group of bacteria exhibiting salt requirement in the range of 3-20%. There is significant diversity among halophiles from saline habitats of India. Preliminary characterization of crude hydrolases established them to be active and stable under more than one extreme condition of high salt, pH, temperature and presence of organic solvents. It is concluded that these halophilic isolates are not only diverse in phylogeny but also in their enzyme characteristics. Their enzymes may be potentially useful for catalysis under harsh operational conditions encountered in industrial processes. The solvent stability among halophilic enzymes seems a generic novel feature making them potentially useful in non-aqueous enzymology.

Screening and isolation of halophilic bacteria producing industrially important enzymes

PubMed Central

Kumar, Sumit; Karan, Ram; Kapoor, Sanjay; S.P., Singh; S.K., Khare

2012-01-01

Halophiles are excellent sources of enzymes that are not only salt stable but also can withstand and carry out reactions efficiently under extreme conditions. The aim of the study was to isolate and study the diversity among halophilic bacteria producing enzymes of industrial value. Screening of halophiles from various saline habitats of India led to isolation of 108 halophilic bacteria producing industrially important hydrolases (amylases, lipases and proteases). Characterization of 21 potential isolates by morphological, biochemical and 16S rRNA gene analysis found them related to Marinobacter, Virgibacillus, Halobacillus, Geomicrobium, Chromohalobacter, Oceanobacillus, Bacillus, Halomonas and Staphylococcus genera. They belonged to moderately halophilic group of bacteria exhibiting salt requirement in the range of 3–20%. There is significant diversity among halophiles from saline habitats of India. Preliminary characterization of crude hydrolases established them to be active and stable under more than one extreme condition of high salt, pH, temperature and presence of organic solvents. It is concluded that these halophilic isolates are not only diverse in phylogeny but also in their enzyme characteristics. Their enzymes may be potentially useful for catalysis under harsh operational conditions encountered in industrial processes. The solvent stability among halophilic enzymes seems a generic novel feature making them potentially useful in non-aqueous enzymology. PMID:24031991

Variable characteristics of bacteriocin-producing Streptococcus salivarius strains isolated from Malaysian subjects.

PubMed

Barbour, Abdelahhad; Philip, Koshy

2014-01-01

Salivaricins are bacteriocins produced by Streptococcus salivarius, some strains of which can have significant probiotic effects. S. salivarius strains were isolated from Malaysian subjects showing variable antimicrobial activity, metabolic profile, antibiotic susceptibility and lantibiotic production. In this study we report new S. salivarius strains isolated from Malaysian subjects with potential as probiotics. Safety assessment of these strains included their antibiotic susceptibility and metabolic profiles. Genome sequencing using Illumina's MiSeq system was performed for both strains NU10 and YU10 and demonstrating the absence of any known streptococcal virulence determinants indicating that these strains are safe for subsequent use as probiotics. Strain NU10 was found to harbour genes encoding salivaricins A and 9 while strain YU10 was shown to harbour genes encoding salivaricins A3, G32, streptin and slnA1 lantibiotic-like protein. Strain GT2 was shown to harbour genes encoding a large non-lantibiotic bacteriocin (salivaricin-MPS). A new medium for maximum biomass production buffered with 2-(N-morpholino)ethanesulfonic acid (MES) was developed and showed better biomass accumulation compared with other commercial media. Furthermore, we extracted and purified salivaricin 9 (by strain NU10) and salivaricin G32 (by strain YU10) from S. salivarius cells grown aerobically in this medium. In addition to bacteriocin production, S. salivarius strains produced levan-sucrase which was detected by a specific ESI-LC-MS/MS method which indicates additional health benefits from the developed strains. The current study established the bacteriocin, levan-sucrase production and basic safety features of S. salivarius strains isolated from healthy Malaysian subjects demonstrating their potential for use as probiotics. A new bacteriocin-production medium was developed with potential scale up application for pharmaceuticals and probiotics from S. salivarius generating different

Comparative Genomic Analysis of a Clinical Isolate of Klebsiella quasipneumoniae subsp. similipneumoniae, a KPC-2 and OKP-B-6 Beta-Lactamases Producer Harboring Two Drug-Resistance Plasmids from Southeast Brazil

PubMed Central

Nicolás, Marisa F.; Ramos, Pablo Ivan Pereira; Marques de Carvalho, Fabíola; Camargo, Dhian R. A.; de Fátima Morais Alves, Carlene; Loss de Morais, Guilherme; Almeida, Luiz G. P.; Souza, Rangel C.; Ciapina, Luciane P.; Vicente, Ana C. P.; Coimbra, Roney S.; Ribeiro de Vasconcelos, Ana T.

2018-01-01

The aim of this study was to unravel the genetic determinants responsible for multidrug (including carbapenems) resistance and virulence in a clinical isolate of Klebsiella quasipneumoniae subsp. similipneumoniae by whole-genome sequencing and comparative analyses. Eighty-three clinical isolates initially identified as carbapenem-resistant K. pneumoniae were collected from nosocomial infections in southeast Brazil. After RAPD screening, the KPC-142 isolate, showing the most divergent DNA pattern, was selected for complete genome sequencing in an Illumina HiSeq 2500 instrument. Reads were assembled into scaffolds, gaps between scaffolds were resolved by in silico gap filling and extensive bioinformatics analyses were performed, using multiple comparative analysis tools and databases. Genome sequencing allowed to correct the classification of the KPC-142 isolate as K. quasipneumoniae subsp. similipneumoniae. To the best of our knowledge this is the first complete genome reported to date of a clinical isolate of this subspecies harboring both class A beta-lactamases KPC-2 and OKP-B-6 from South America. KPC-142 has one 5.2 Mbp chromosome (57.8% G+C) and two plasmids: 190 Kbp pKQPS142a (50.7% G+C) and 11 Kbp pKQPS142b (57.3% G+C). The 3 Kbp region in pKQPS142b containing the blaKPC−2 was found highly similar to that of pKp13d of K. pneumoniae Kp13 isolated in Southern Brazil in 2009, suggesting the horizontal transfer of this resistance gene between different species of Klebsiella. KPC-142 additionally harbors an integrative conjugative element ICEPm1 that could be involved in the mobilization of pKQPS142b and determinants of resistance to other classes of antimicrobials, including aminoglycoside and silver. We present the completely assembled genome sequence of a clinical isolate of K. quasipneumoniae subsp. similipneumoniae, a KPC-2 and OKP-B-6 beta-lactamases producer and discuss the most relevant genomic features of this important resistant pathogen in comparison

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.

The isolation and identification of endophytic bacteria from mangrove (Sonneratia alba) that produces gelatinase

NASA Astrophysics Data System (ADS)

Nursyam, H.; Prihanto, A. A.; Warasari, N. I.; Saadah, M.; Masrifa, R. E.; Nabila, N. A.; Istiqfarin, N.; Siddiq, I. J.

2018-04-01

Gelatinase is an enzyme that hydrolyze gelatin into gelatin hydrolyzate. The purpose of this study was to isolate and to identify endophytic bacteria from Sonneratia alba mangrove which able to produce gelatinase enzyme. Sonneratia alba mangroves was obtained from Bajul Mati Beach, Malang Regency. The samples in this study were, stems, and leaves. Pure cultured bacteria were investigated for its capability for producing gelatinase enzyme by using gelatin media. Best producer would further be analyzed its species using microbact system. Screening process resulted in 3 positive isolates, namely code isolate of R, B, and L. R which was isolate from root of S. alba was the best producer for gelatinase. Identification process with morphology and microbact system revelaed that A. SBM is a Gram-negative bacterium that has a basil cell shape, with a diameter colony of 2.19 mm. Based on the microbact system test carried out, the bacteria is Pseudomonas aeruginosa.

Characterization of the RpoS Status of Clinical Isolates of Salmonella enterica

PubMed Central

Robbe-Saule, Véronique; Algorta, Gabriela; Rouilhac, Isabelle; Norel, Françoise

2003-01-01

The stationary-phase-inducible sigma factor, σS (RpoS), is the master regulator of the general stress response in Salmonella and is required for virulence in mice. rpoS mutants can frequently be isolated from highly passaged laboratory strains of Salmonella. We examined the rpoS status of 116 human clinical isolates of Salmonella, including 41 Salmonella enterica serotype Typhi strains isolated from blood, 38 S. enterica serotype Typhimurium strains isolated from blood, and 37 Salmonella serotype Typhimurium strains isolated from feces. We examined the abilities of these strains to produce the σS protein, to express RpoS-dependent catalase activity, and to resist to oxidative stress in the stationary phase of growth. We also carried out complementation experiments with a cloned wild-type rpoS gene. Our results showed that 15 of the 41 Salmonella serotype Typhi isolates were defective in RpoS. We sequenced the rpoS allele of 12 strains. This led to identification of small insertions, deletions, and point mutations resulting in premature stop codons or affecting regions 1 and 2 of σS, showing that the rpoS mutations are not clonal. Thus, mutant rpoS alleles can be found in freshly isolated clinical strains of Salmonella serotype Typhi, and they may affect virulence properties. Interestingly however, no rpoS mutants were found among the 75 Salmonella serotype Typhimurium isolates. Strains that differed in catalase activity and resistance to hydrogen peroxide were found, but the differences were not linked to the rpoS status. This suggests that Salmonella serotype Typhimurium rpoS mutants are counterselected because rpoS plays a role in the pathogenesis of Salmonella serotype Typhimurium in humans or in the transmission cycle of the disease. PMID:12902215

Regional variation in the prevalence of extended-spectrum beta-lactamase-producing clinical isolates in the Asia-Pacific region (SENTRY 1998-2002).

PubMed

Hirakata, Yoichi; Matsuda, Junichi; Miyazaki, Yoshitsugu; Kamihira, Shimeru; Kawakami, Sayoko; Miyazawa, Yukihisa; Ono, Yasuo; Nakazaki, Nobuhiko; Hirata, Yasuyoshi; Inoue, Matsuhisa; Turnidge, John D; Bell, Jan M; Jones, Ronald N; Kohno, Shigeru

2005-08-01

We examined the prevalence of extended-spectrum beta-lactamase (ESBL)-producing strains of Klebsiella pneumoniae, Klebsiella oxytoca, Escherichia coli, Proteus mirabilis, Citrobacter koseri, and Salmonella spp. that were isolated as part of the SENTRY Asia-Pacific Surveillance Program between 1998 and 2002. During the study period, a total of 6,388 strains were gathered from 17 medical centers in 7 countries and examined for ESBL production and hyperproduction of K. oxytoca chromosomal K1 beta-lactamase enzyme. High rates of confirmed ESBL-producing isolates were found in K. pneumoniae strains from Singapore (35.6%), followed by those from mainland China (30.7%), South Africa (28.1%), and the Philippines (21.9%), whereas the rates were less than 10% in Japan and Australia. ESBL-producing E. coli strains were also prominent in mainland China (24.5%), Hong Kong (14.3%), and Singapore (11.3%). ESBL-producing K. oxytoca were common in the Philippines (38.5%), Singapore (33.3%), and China (30.0%). Hyperproduction of K. oxytoca chromosomal K1 beta-lactamase enzyme was common in Australia and Japan. P. mirabilis strains from Singapore produced ESBL (17.9%) despite the low prevalence (0-8.1%) in other countries. Few ESBL-producing C. koseri and Salmonella spp. strains were found in Japan, Singapore, Taiwan, and South Africa. Although there was variation among countries in substrate preference, ceftazidime was more likely to detect presumptive ESBL phenotype in K. pneumoniae and aztreonam more likely in E. coli, whereas ceftriaxone was the best substrate for the confirmation of ESBL production. ESBL-producing strains showed high levels of co-resistance to aminoglycosides, tetracycline, trimethoprim-sulfamethoxazole, and ciprofloxacin. Imipenem retained activity against all ESBL-producing strains. Organisms expressing ESBLs are widely distributed in the Asia-Pacific region, although prevalence rates vary significantly.

Isolation and characterization of endophytic huperzine A-producing fungi from Huperzia serrata.

PubMed

Wang, Ya; Zeng, Qing Gui; Zhang, Zhi Bin; Yan, Ri Ming; Wang, Ling Yun; Zhu, Du

2011-09-01

Huperzia serrata is a producer of huperzine A (HupA), a cholinesterase inhibitor (ChEI). Over 120 endophytic fungi were recovered from this plant and screened for Hup-A and nine were found. These nine represented seven different fungal genera with the most significant producer being Shiraia sp. A total of 127 endophytic fungi isolates obtained from the root, stem, and leaf segments of H. serrata were grouped into 19 genera based on their morphological traits and sequence analysis of the internal transcribed spacers (ITS1-5.8S-ITS2), indicating endophytic fungi in H. serrata are diverse and abundant. Aspergillus, Podospora, Penicillium, Colletotrichum, and Acremonium were the frequent genera, whereas the remaining genera were infrequent groups. Overall, 39 endophytic fungi isolates showed acetylcholinesterase (AChE) inhibition in vitro. Nine endophytic fungi isolates from seven distinct genera were capable of producing HupA verified by thin-layer chromatography and reverse-phase high-performance liquid chromatography (RP-HPLC). Among the HupA-producing fungi, the yield of HupA produced by the Shiraia sp. Slf14 was 327.8 μg/l in potato dextrose broth, and the fungal HupA was further validated by mass spectrometry (ESI-MS). The present study demonstrated that H. serrata was a fascinating fungal reservoir for producing HupA and other ChEIs.

Plasmid analyses in clinical isolates of Bacteroides fragilis and other Bacteroides species.

PubMed Central

Wallace, B L; Bradley, J E; Rogolsky, M

1981-01-01

Plasmid analyses were performed on Bacteroides strains isolated from clinical specimens. Of 32 Bacteroides strains, 8 were found to contain plasmids. Seven of these eight strains were B. fragilis, and the other one was B. distasonis. Three of these eight strains harbored only a 3.0-megadalton plasmid. Two strains had only a 2.0-megadalton plasmid, and one had 2.0-, 3.0-megadalton plasmid. Of the remaining two strains, one had 2.0-, 3.0-, and 5.0-megadalton plasmids, and the other had 3.0- and 5.0-megadalton plasmids. Beta-Lactamase was produced by 93% of the clinical isolates. Seven of the eight plasmid-carrying strains were cadmium resistant, five were zinc resistant, four were mercury resistant, and two expressed a brick-red fluorescence under ultraviolet light. None of these traits could be associated with a plasmid after performing either curing experiments or genetic transfer experiments by cell-to-cell contact. Images PMID:6974737

Heterogeneous production of proteases from Brazilian clinical isolates of Pseudomonas aeruginosa.

PubMed

Galdino, Anna Clara M; Viganor, Lívia; Ziccardi, Mariangela; Nunes, Ana Paula F; Dos Santos, Kátia R N; Branquinha, Marta H; Santos, André L S

2017-12-01

Pseudomonas aeruginosa is an important human pathogen that causes severe infections in a wide range of immunosuppressed patients. Herein, we evaluated the proteolytic profiles of 96 Brazilian clinical isolates of P. aeruginosa recovered from diverse anatomical sites. Cell-associated and extracellular proteases were evidenced by gelatin-SDS-PAGE and by the cleavage of soluble gelatin. Elastase was measured by using the peptide substrate N-succinyl-Ala-Ala-Ala-p-nitroanilide. The prevalence of elastase genes (lasA and lasB) was evaluated by PCR. Bacterial extracts were initially applied on gelatin-SDS-PAGE and the results revealed four distinct zymographic profiles as follows: profile I (composed by bands of 145, 118 and 50kDa), profile II (118 and 50kDa), profile III (145kDa) and profile IV (118kDa). All the proteolytic enzymes were inhibited by EDTA, identifying them as metalloproteases. The profile I was the most detected in both cellular (79.2%) and extracellular (84.4%) extracts. Overall, gelatinase and elastase activities measured in the spent culture media were significantly higher (around 2-fold) compared to the cellular extracts and the production level varied according to the site of bacterial isolation. For instance, tracheal secretion isolates produced elevated amount of gelatinase and elastase measured in both cellular and extracellular extracts. The prevalence of elastase genes revealed that 100% isolates were lasB-positive and 85.42% lasA-positive. Some positive/negative correlations were showed concerning the production of gelatinase, elastase, isolation site and antimicrobial susceptibility. The protease production was highly heterogeneous in Brazilian clinical isolates of P. aeruginosa, which corroborates the genomic/metabolic versatility of this pathogen. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

First Isolate of KPC-2-Producing Klebsiella pneumonaie Sequence Type 23 from the Americas

PubMed Central

Cejas, Daniela; Fernández Canigia, Liliana; Rincón Cruz, Giovanna; Elena, Alan X.; Maldonado, Ivana; Gutkind, Gabriel O.

2014-01-01

KPC-2-producing Klebsiella pneumoniae isolates mainly correspond to clonal complex 258 (CC258); however, we describe KPC-2-producing K. pneumoniae isolates belonging to invasive sequence type 23 (ST23). KPC-2 has scarcely been reported to occur in ST23, and this report describes the first isolation of this pathogen in the Americas. Acquisition of resistant markers in virulent clones could mark an evolutionary step toward the establishment of these clones as major nosocomial pathogens. PMID:25031447

Isolation and genetic characterization of metallo-β-lactamase and carbapenamase producing strains of Acinetobacter baumannii from patients at Tehran hospitals

PubMed Central

Shahcheraghi, F; Abbasalipour, M; Feizabadi, MM; Ebrahimipour, GH; Akbari, N

2011-01-01

Background and Objective Carbapenems are therapeutic choice against infections caused by gram-negative bacilli including strains of Acinetobacter baumannii. Resistance to these antibiotics is mediated by efflux pumps, porins, PBPs and ß-lactamases. The aim of this study was to determine the possibility of existence of MBLs, OXAs and GES-1 betalactamase genes among clinical isolates of Acinetobacter collected from Tehran hospitals. Material and Methods Two hundred and three Acinetobacter isolates were collected from patient at Tehran hospitals. The isolates were identified using biochemical tests. The susceptibility to different antibiotics was evaluated by disk diffusion method and MICs of imipenem were determined using Micro broth dilution method (CLSI). PCR was performed for detection of bla VIM-2, bla SPM-1, bla IMP-2, bla GES-1, bla OXA-51, bla OXA-23 betalactamase genes. Clonal relatedness was estimated by PFGE with the restriction enzyme SmaI. Results and Conclusion Of 100 isolates of imipenem resistant Acinetobacter spp. collected from Tehran hospitals in 2009 and 2010, 6 isolates produced metallo-beta-lactamases and 94 isolates produced OXA-type carbapenemase. The bla SPM-1, bla GES-1, bla OXA-51, bla OXA-23 genes were detected by PCR among 6, 2, 94 and 84 isolates of A. baumannii, respectively. The MICs of isolates to imipenem were 8–128 µg/mL. PFGE analysis of 29 bla OXA-51 and bla OXA-23-positive A. baumannii isolates gave 6 different patterns. This is the first report of SPM-1 and GES-1 beta-lactamase producing A. baumannii. Production of the OXA-23, OXA-51, GES-1 and SPM-1 enzyme presents an emerging threat of carbapenem resistance among A. baumannii in Iran. PMID:22347585

Genetic makeup of Shiga toxin-producing Escherichia coli in relation to clinical symptoms and duration of shedding: a microarray analysis of isolates from Swedish children.

PubMed

Matussek, A; Jernberg, C; Einemo, I-M; Monecke, S; Ehricht, R; Engelmann, I; Löfgren, S; Mernelius, S

2017-08-01

Shiga toxin (Stx)-producing Escherichia coli (STECs) cause non-bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome, and are the primary cause of acute renal failure in children worldwide. This study investigated the correlation of genetic makeup of STEC strains as revealed by DNA microarray to clinical symptoms and the duration of STEC shedding. All STEC isolated (n = 96) from patients <10 years of age in Jönköping County, Sweden from 2003 to 2015 were included. Isolates were characterized by DNA microarray, including almost 280 genes. Clinical data were collected through a questionnaire and by reviewing medical records. Of the 96 virulence genes (including stx) in the microarray, 62 genes were present in at least one isolate. Statistically significant differences in prevalence were observed for 21 genes when comparing patients with bloody diarrhea (BD) and with non-bloody stool (18 of 21 associated with BD). Most genes encode toxins (e.g., stx2 alleles, astA, toxB), adhesion factors (i.e. espB_O157, tir, eae), or secretion factors (e.g., espA, espF, espJ, etpD, nleA, nleB, nleC, tccP). Seven genes were associated with prolonged stx shedding; the presence of three genes (lpfA, senB, and stx1) and the absence of four genes (espB_O157, espF, astA, and intI1). We found STEC genes that might predict severe disease outcome already at diagnosis. This can be used to develop diagnostic tools for risk assessment of disease outcome. Furthermore, genes associated with the duration of stx shedding were detected, enabling a possible better prediction of length of STEC carriage after infection.

Isolation of KPC 3-producing Enterobacter aerogenes in a patient colonized by MDR Klebsiella pneumoniae.

PubMed

Venditti, Carolina; Villa, Laura; Capone, Alessandro; Fortini, Daniela; D'Arezzo, Silvia; Nisii, Carla; Bordi, Eugenio; Puro, Vincenzo; Antonini, Mario; Carattoli, Alessandra; Cataldo, Maria Adriana; Petrosillo, Nicola; Di Caro, Antonino

2016-10-01

We describe the interspecies transmission of the plasmid-mediated blaKPC-3 gene, which confers carbapenem resistance, between clinically relevant gram-negative bacteria in a single patient. A KPC-3 producing Enterobacter aerogenes was isolated from a hospitalized patient previously colonized and then infected by a Klebsiella pneumoniae ST101 carrying the blaKPC-3 gene. The strains showed identical plasmids. Since intense horizontal exchanges among bacteria can occur in the gut, clinicians should be aware that patients colonized by carbapenem-resistant K. pneumoniae could become carriers of other carbapenem-resistant Enterobacteriaceae.

Relationship between clinical site of isolation and ability to form biofilms in vitro in nontypeable Haemophilus influenzae.

PubMed

Obaid, Najla A; Jacobson, Glenn A; Tristram, Stephen

2015-03-01

Nontypeable Haemophilus influenzae (NTHi) is an opportunistic pathogen associated with a range of infections, including various lower respiratory infections, otitis media, and conjunctivitis. There is some debate as to whether or not NTHi produces biofilms and, if so, whether or not this is relevant to pathogenesis. Although many studies have examined the association between in vitro biofilm formation and isolates from a specific infection type, few have made comparisons from isolates from a broad range of isolates grouped by clinical source. In our study 50 NTHi from different clinical sources, otitis media, conjunctivitis, lower respiratory tract infections in both cystic fibrosis and non-cystic fibrosis patients, and nasopharyngeal carriage, plus 10 nasopharyngeal isolates of the commensal Haemophilus haemolyticus were tested for the ability to form biofilm by using a static microtitre plate crystal violet assay. A high degree of variation in biofilm forming ability was observed across all isolates, with no statistically significant differences observed between the groups, with the exception of the isolates from conjunctivitis. These isolates had uniformly lower biofilm forming ability compared with isolates from the other groups (p < 0.005).

Clinical Features and Molecular Epidemiology of CMY-Type β-Lactamase-Producing Escherichia coli

PubMed Central

Sidjabat, Hanna E.; Paterson, David L.; Qureshi, Zubair A.; Adams-Haduch, Jennifer M.; O’Keefe, Alexandra; Pascual, Alvaro; Rodríguez-Baño, Jesús; Doi, Yohei

2009-01-01

Background Knowledge on the clinical features of infections caused by Escherichia coli producing plasmid-mediated AmpC β-lactamase is limited. Of the several groups of plasmid-mediated AmpC β-lactamase, CMY-type β-lactamase is the most common in the United States. Methods We prospectively identified E. coli producing CMY-type β-lactamase and collected clinical data over a seven-month period. A retrospective cohort study was performed to identify features associated with these cases, using cases due to extended-spectrum β-lactamase (ESBL)-producing E. coli as controls. Pulsed-field gel electrophoresis (PFGE), plasmid analysis and phylogenetic typing were performed. Results Twenty-two cases with CMY-producing E. coli and 25 cases with ESBL-producing E. coli were identified. The demographics of the patients were similar between the CMY and ESBL cohorts. CMY cases were significantly more likely to represent symptomatic infection compared with ESBL cases (P=0.028). The CMY-type β-lactamase was identified as CMY-2 or its variants. Ninety-four percent of the CMY-producing isolates belonged to E. coli phylogenetic groups B2 and D, which are associated with virulence. Many of them shared similar plasmid profiles, whereas the PFGE profiles were diverse. Co-resistance to non-β-lactam antimicrobials was common. Conclusion In Pittsburgh, CMY-producing E. coli is almost as common as ESBL-producing E. coli and causes symptomatic infection in the majority of cases. PMID:19187027

[Comparison of different methods for the identification of Candida species isolated from clinical specimens].

PubMed

Cetinkaya, Zafer; Altindiş, Mustafa; Aktepe, Orhan Cem; Karabiçak, Nilgün

2003-10-01

The aim of this study was to compare the different methods for the identification of Candida strains isolated from clinical specimens. The methods of germ tube examination, chlamydospore examination formed on the rice Tween-80 (RT-80) agar and evaluation of colony morphologies on the two chromogenic agars (CHROMagar Candida, Albicans ID), were compared with a reference API 20C AUX (bioMerieux, France) automated system based on the carbohydrate assimilation, for the identification of a total 255 Candida isolates. Of them, 173 (67.8%) were identified as C. albicans, 37 (14.5%) were C. glabrata, 23 (9%) were C. krusei, 9 (3.5%) were C. tropicalis, 9 (3.5%) were C. kefyr, 2 (0.8%) were C. guillermondii and 2 (0.8%) were C. parapsilosis, by API 20C AUX system. In the view of these results, 146 (84.4%) of C. albicans strains were identified by germ tube examination, 161 (93.1%) of C. albicans strains and 208 (81.5%) of total strains were identified by chlamydospore examination. 169 (97.7%) of C. albicans strains and 231 (90.6%) of total strains were identified by CHROMagar Candida method, and 168 (97.1%) of C. albicans strains were identified by Albicans ID method, correctly. In the CHROMagar Candida medium, 169 C. albicans isolates have produced bright green colored colonies, whereas 33 (89.2%) isolates which produced dark pink/purple colored colonies were identified as C. glabrata, 7 (77.8%) isolates which produced metalical blue colored colonies were identified as C. tropicalis and 22 (95.6%) isolates which produced pale pink colored colonies were identified as C. krusei. In the Albicans ID medium, four of the 172 isolates which were evaluated as C. albicans initially by producing blue colored colonies, have been identified as C. tropicalis by API 20C AUX system. The sensitivities and specificities of germ tube examination, RT-80, CHROMagar Candida and Albicans ID methods were found as follows, respectively; 84.4% and 100%, 93.1% and 100%, 97.7% and 100%, 99.4% and 95

Interspecific Small Molecule Interactions between Clinical Isolates of Pseudomonas aeruginosa and Staphylococcus aureus from Adult Cystic Fibrosis Patients

PubMed Central

Mitchell, Gabriel; Déziel, Eric; Dekimpe, Valérie; Cantin, André M.; Frost, Eric; Malouin, François

2014-01-01

Pseudomonas aeruginosa and Staphylococcus aureus are the most prevalent pathogens in airway infections of cystic fibrosis (CF) patients. We studied how these pathogens coexist and interact with each other. Clinical isolates of both species were retrieved from adult CF patients. Culture supernatants from 63 P. aeruginosa isolates triggered a wide range of biofilm-stimulatory activities when added to the culture of a control S. aureus strain. The extent of biofilm formation by S. aureus was positively correlated to the levels of the 2-alkyl-4-(1H)-quinolones (AQs) Pseudomonas Quinolone Signal (PQS) and 2-heptyl-4-hydroxy quinoline N-oxide (HQNO) produced by the P. aeruginosa isolates. Supernatants from P. aeruginosa isogenic mutants deficient in PQS and HQNO production stimulated significantly less biofilm formation by S. aureus than that seen with the parental strain PA14. When studying co-isolated pairs of P. aeruginosa and S. aureus retrieved from patients showing both pathogens, P. aeruginosa supernatants stimulated less biofilm production by the S. aureus counterparts compared to that observed using the control S. aureus strain. Accordingly, some P. aeruginosa isolates produced low levels of exoproducts and also some of the clinical S. aureus isolates were not stimulated by their co-isolates or by PA14 despite adequate production of HQNO. This suggests that colonization of the CF lungs promotes some type of strain selection, or that co-existence requires specific adaptations by either or both pathogens. Results provide insights on bacterial interactions in CF. PMID:24466207

Prevalence of Stx-producing Shigella species isolated from French Travelers Returning from the Caribbean: An Emerging Pathogen with International Implications

PubMed Central

Gray, Miranda D.; Lacher, David W.; Leonard, Susan R.; Abbott, Jason; Zhao, Shaohua; Lampel, Keith A.; Prothery, Estelle; Gouali, Malika; Weill, François-Xavier; Maurelli, Anthony T.

2015-01-01

Shiga toxins are potent cytotoxins that inhibit host cell protein synthesis, leading to cell death. Classically, these toxins are associated with intestinal infections due to Shiga toxin-producing Escherichia coli or Shigella dysenteriae serotype 1 and infections with these strains can lead to hemolytic uremic syndrome. Over the past decade there is increasing recognition that Shiga toxin is produced by additional Shigella species. We recently reported the presence and expression of stx genes in Shigella flexneri 2a clinical isolates. The toxin genes were carried by a new stx-encoding bacteriophage and infection with these strains correlated with recent travel to Haiti or the Dominican Republic. In this study we further explored the epidemiological link to this region by utilizing the French National Reference Center for Escherichia coli, Shigella and Salmonella collection to survey the frequency of Stx-producing Shigella species isolated from French travelers returning from the Caribbean. About 21% of the isolates tested were found to encode and produce Stx. These isolates included strains of S. flexneri 2a, S. flexneri Y, and S. dysenteriae 4. All of the travelers whom were infected with Stx-producing Shigella had recently traveled to Haiti, the Dominican Republic, or French Guiana. Furthermore, whole genome sequencing found that the toxin genes were encoded by a prophage that was highly identical to the phage we identified in our previous study. These findings demonstrate that this new stx-encoding prophage is circulating within that geographical area, has spread to other continents, and is capable of spreading to multiple Shigella serogroups. PMID:25980352

Extended-Spectrum-β-Lactamase-Producing Enterobacteriaceae Isolated from Vegetables Imported from the Dominican Republic, India, Thailand, and Vietnam

PubMed Central

Zurfluh, Katrin; Nüesch-Inderbinen, Magdalena; Morach, Marina; Zihler Berner, Annina; Hächler, Herbert

2015-01-01

To examine to what extent fresh vegetables imported into Switzerland represent carriers of extended-spectrum-β-lactamase (ESBL)-producing Enterobacteriaceae, 169 samples of different types of fresh vegetables imported into Switzerland from the Dominican Republic, India, Thailand, and Vietnam were analyzed. Overall, 25.4% of the vegetable samples yielded one or more ESBL-producing Enterobacteriaceae, 78.3% of which were multidrug resistant. Sixty isolates were obtained: Escherichia coli, 26; Klebsiella pneumoniae, 26; Enterobacter cloacae, 6; Enterobacter aerogenes, 1; and Cronobacter sakazakii, 1. We found 29 isolates producing CTX-M-15, 8 producing CTX-M-14, 7 producing CTX-M-55, 3 producing CTX-M-65, 1 each producing CTX-M-1, CTX-M-3, CTX-M-27, and CTX-M-63, 5 producing SHV-2, 3 producing SHV-12, and 1 producing SHV-2a. Four of the E. coli isolates belonged to epidemiologically important clones: CTX-M-15-producing B2:ST131 (1 isolate), D:ST405 (1 isolate), and D:ST38 (2 isolates). One of the D:ST38 isolates belonged to the extraintestinal enteroaggregative E. coli (EAEC) D:ST38 lineage. Two of the K. pneumoniae isolates belonged to the epidemic clones sequence type 15 (ST15) and ST147. The occurrence of antibiotic-resistant pathogenic and commensal Enterobacteriaceae in imported agricultural foodstuffs constitutes a source of ESBL genes and a concern for food safety. PMID:25724954

Cariogenic properties of Streptococcus mutans clinical isolates with sortase defects.

PubMed

Lapirattanakul, Jinthana; Takashima, Yukiko; Tantivitayakul, Pornpen; Maudcheingka, Thaniya; Leelataweewud, Pattarawadee; Nakano, Kazuhiko; Matsumoto-Nakano, Michiyo

2017-09-01

In Streptococcus mutans, a Gram-positive pathogen of dental caries, several surface proteins are anchored by the activity of sortase enzyme. Although various reports have shown that constructed S. mutans mutants deficient of sortase as well as laboratory reference strains with a sortase gene mutation have low cariogenic potential, no known studies have investigated clinical isolates with sortase defects. Here, we examined the cariogenic properties of S. mutans clinical isolates with sortase defects as well as caries status in humans harboring such defective isolates. Sortase-defective clinical isolates were evaluated for biofilm formation, sucrose-dependent adhesion, stress-induced dextran-dependent aggregation, acid production, and acid tolerance. Additionally, caries indices of subjects possessing such defective isolates were determined. Our in vitro results indicated that biofilm with a lower quantity was formed by sortase-defective as compared to non-defective isolates. Moreover, impairments of sucrose-dependent adhesion and stress-induced dextran-dependent aggregation were found among the isolates with defects, whereas no alterations were seen in regard to acid production or tolerance. Furthermore, glucan-binding protein C, a surface protein anchored by sortase activity, was predominantly detected in culture supernatants of all sortase-defective S. mutans isolates. Although the sortase-defective isolates showed lower cariogenic potential because of a reduction in some cariogenic properties, deft/DMFT indices revealed that all subjects harboring those isolates had caries experience. Our findings suggest the impairment of cariogenic properties in S. mutans clinical isolates with sortase defects, though the detection of these defective isolates seemed not to imply low caries risk in the subjects harboring them. Copyright © 2017 Elsevier Ltd. All rights reserved.

Clonal Dissemination of Extended-Spectrum β-Lactamase (ESBL)-Producing Klebsiella pneumoniae Isolates in a Korean Hospital

PubMed Central

Ko, Kwan Soo; Yeom, Joon-Sup; Lee, Mi Young; Peck, Kyong Ran

2008-01-01

In this study, we investigated the molecular characteristics of extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae isolates that were recovered from an outbreak in a Korean hospital. A new multilocus sequence typing (MLST) scheme for K. pneumoniae based on five housekeeping genes was developed and was evaluated for 43 ESBL-producing isolates from an outbreak as well as 38 surveillance isolates from Korea and also a reference strain. Overall, a total of 37 sequence types (STs) and six clonal complexes (CCs) were identified among the 82 K. pneumoniae isolates. The result of MLST analysis was concordant with that of pulsedfield gel electrophoresis. Most of the outbreak isolates belonged to a certain clone (ST2), and they produced SHV-1 and CTX-M14 enzymes, which was a different feature from that of the K. pneumoniae isolates from other Korean hospitals (ST20 and SHV-12). We also found a different distribution of CCs between ESBL-producing and -nonproducing K. pneumoniae isolates. The MLST method we developed in this study could provide unambiguous and well-resolved data for the epidemiologic study of K. pneumoniae. The outbreak isolates showed different molecular characteristics from the other K. pneumoniae isolates from other Korean hospitals. PMID:18303199

Comparison of CTX-M-14- and CTX-M-15-producing Escherichia coli and Klebsiella pneumoniae isolates from patients with bacteremia.

PubMed

Shin, Juyoun; Kim, Dae Hun; Ko, Kwan Soo

2011-07-01

Recently, CTX-M-15-producing Enterobacteriaceae has disseminated worldwide. To better understand the success of CTX-M-15-type extended-spectrum β-lactamase, we compared the CTX-M-15-producing Escherichia coli and Klebsiella pneumoniae isolates with CTX-M-14-producing E. coli and K. pneumoniae isolates that had been more prevalent before the recent increase of CTX-M-15 in Korea. Eighty-nine CTX-M-producing E. coli bloodstream infection isolates and 33 K. pneumoniae bloodstream infection isolates were collected in 2008 from nine hospitals in Korea. In vitro susceptibility testing and multilocus sequence typing were performed for all isolates. Phylogenetic groupings and distribution of virulence determinants and addiction systems were examined for only E. coli isolates. Among the 89 CTX-M-producing E. coli isolates, 54 isolates (60.7%) contained bla(CTx-M-15) and bla(CTx-M-14) was identified in 31 isolates (34.8%). Among 33 CTX-M-producing K. pneumoniae isolates, bla(CTx-M-14) and bla(CTx-M-15) were identified in 18 (54.5%) and 15 (45.5%) isolates, respectively. While CTX-M-14- and CTX-M-15-producing E. coli isolates displayed similar antimicrobial resistance rates, CTX-M-15-producing K. pneumoniae isolates showed significantly higher resistance rates of ciprofloxacin and piperacillin-tazobactam than CTX-M-14-producing isolates. ST131 and ST405 were the main clones in both CTX-M-14- and CTX-M-15-producing E. coli isolates. Although the frequency of virulence determinants was similar between two E. coli groups, ST131 and ST405 isolates producing CTX-M-15 showed higher frequency of determinants. In addition, CTX-M-15-producing E. coli isolates showed higher prevalence of addiction systems, particularly vagCD. ST405 showed the highest prevalence rates among main E. coli clones. In K. pneumoniae, ST15 and ST11, with high resistance rates, were the main clones of CTX-M-15-producing isolates, but no main clones was found among CTX-M-14-producing isolates because of extreme

Phylogenetic Analysis of Polygalacturonase-Producing Bacillus and Pseudomonas Isolated From Plant Waste Material

PubMed Central

Sohail, Muhammad; Latif, Zakia

2016-01-01

Background: Keeping in mind the commercial application of polygalacturonase (PG) in juice and beverages industry, bacterial strains were isolated from rotten fruits and vegetables to screen for competent producers of PG. Objectives: In this study, the plate method was used for preliminary screening of polygalacturonase-producing bacteria, while the Dinitrosalicylic Acid (DNS) method was used for quantifications of PG. Materials and Methods: Biochemically-identified polygalacturonase-producing Bacillus and Pseudomonas species were further characterized by molecular markers. The genetic diversity among these selected strains was analyzed by investigating microsatellite distribution in their genome. Out of 110 strains, 17 competent strains of Bacillus and eight strains of Pseudomonas were selected, identified and confirmed biochemically. Selected strains were characterized by 16S rRNA sequencing and data was submitted to the national center for biotechnology information (NCBI) website for accession numbers. Results: Among the Bacillus, Bacillus vallismortis (JQ990307) isolated from mango was the most competent producer of PG; producing up to 4.4 U/µL. Amongst Pseudomonas, Pseudomonas aeruginosa (JQ990314) isolated from oranges was the most competent PG producer equivalent to B. vallismortis (JQ990307). To determine genetic diversity of different strains of Pseudomonas and Bacillus varying in PG production, fingerprinting was done on the basis of Simple Sequence Repeats (SSR) or microsatellites. The data was analyzed and a phylogenetic tree was constructed using the Minitab 3 software for comparison of bacterial isolates producing different concentrations of PG. Fingerprinting showed that presence or absence of certain microsatellites correlated with the ability of PG production. Conclusions: Bacteria from biological waste were competent producers of PG and must be used on an industrial scale to cope with the demand of PG in the food industry. PMID:27099686

Four Main Virotypes among Extended-Spectrum-β-Lactamase-Producing Isolates of Escherichia coli O25b:H4-B2-ST131: Bacterial, Epidemiological, and Clinical Characteristics

PubMed Central

Mora, Azucena; Mamani, Rosalia; López, Cecilia; Blanco, Miguel; Dahbi, Ghizlane; Herrera, Alexandra; Marzoa, Juan; Fernández, Val; de la Cruz, Fernando; Martínez-Martínez, Luis; Alonso, María Pilar; Nicolas-Chanoine, Marie-Hélène; Johnson, James R.; Johnston, Brian; López-Cerero, Lorena; Pascual, Álvaro; Rodríguez-Baño, Jesús

2013-01-01

A total of 1,021 extended-spectrum-β-lactamase-producing Escherichia coli (ESBLEC) isolates obtained in 2006 during a Spanish national survey conducted in 44 hospitals were analyzed for the presence of the O25b:H4-B2-ST131 (sequence type 131) clonal group. Overall, 195 (19%) O25b-ST131 isolates were detected, with prevalence rates ranging from 0% to 52% per hospital. Molecular characterization of 130 representative O25b-ST131 isolates showed that 96 (74%) were positive for CTX-M-15, 15 (12%) for CTX-M-14, 9 (7%) for SHV-12, 6 (5%) for CTX-M-9, 5 (4%) for CTX-M-32, and 1 (0.7%) each for CTX-M-3 and the new ESBL enzyme CTX-M-103. The 130 O25b-ST131 isolates exhibited relatively high virulence scores (mean, 14.4 virulence genes). Although the virulence profiles of the O25b-ST131 isolates were fairly homogeneous, they could be classified into four main virotypes based on the presence or absence of four distinctive virulence genes: virotypes A (22%) (afa FM955459 positive, iroN negative, ibeA negative, sat positive or negative), B (31%) (afa FM955459 negative, iroN positive, ibeA negative, sat positive or negative), C (32%) (afa FM955459 negative, iroN negative, ibeA negative, sat positive), and D (13%) (afa FM955459 negative, iroN positive or negative, ibeA positive, sat positive or negative). The four virotypes were also identified in other countries, with virotype C being overrepresented internationally. Correspondingly, an analysis of XbaI macrorestriction profiles revealed four major clusters, which were largely virotype specific. Certain epidemiological and clinical features corresponded with the virotype. Statistically significant virotype-specific associations included, for virotype B, older age and a lower frequency of infection (versus colonization), for virotype C, a higher frequency of infection, and for virotype D, younger age and community-acquired infections. In isolates of the O25b:H4-B2-ST131 clonal group, these findings uniquely define four main

Genetic diversity of clinical and environmental isolates of Vibrio cholerae determined by amplified fragment length polymorphism fingerprinting.

PubMed

Jiang, S C; Matte, M; Matte, G; Huq, A; Colwell, R R

2000-01-01

Vibrio cholerae, the causative agent of major epidemics of diarrheal disease in Bangladesh, South America, Southeastern Asia, and Africa, was isolated from clinical samples and from aquatic environments during and between epidemics over the past 20 years. To determine the evolutionary relationships and molecular diversity of these strains, in order to understand sources, origin, and epidemiology, a novel DNA fingerprinting technique, amplified fragment length polymorphism (AFLP), was employed. Two sets of restriction enzyme-primer combinations were tested for fingerprinting of V. cholerae serogroup O1, O139, and non-O1, O139 isolates. Amplification of HindIII- and TaqI-digested genomic DNA produced 30 to 50 bands for each strain. However, this combination, although capable of separating environmental isolates of O1 and non-O1 strains, was unable to distinguish between O1 and O139 clinical strains. This result confirmed that clinical O1 and O139 strains are genetically closely related. On the other hand, AFLP analyses of restriction enzyme ApaI- and TaqI-digested genomic DNA yielded 20 to 30 bands for each strain, but were able to separate O1 from O139 strains. Of the 74 strains examined with the latter combination, 26 serogroup O1 strains showed identical banding patterns and were represented by the O1 El Tor strain of the seventh pandemic. A second group, represented by O139 Bengal, included 12 strains of O139 clinical isolates, with 7 from Thailand, 3 from Bangladesh, and 2 from India. Interestingly, an O1 clinical isolate from Africa also grouped with the O139 clinical isolates. Eight clinical O1 isolates from Mexico grouped separately from the O1 El Tor of the seventh pandemic, suggesting an independent origin of these isolates. Identical fingerprints were observed between an O1 environmental isolate from a river in Chile and an O1 clinical strain from Kenya, both isolated more than 10 years apart. Both strains were distinct from the O1 seventh pandemic strain

First isolate of KPC-2-producing Klebsiella pneumonaie sequence type 23 from the Americas.

PubMed

Cejas, Daniela; Fernández Canigia, Liliana; Rincón Cruz, Giovanna; Elena, Alan X; Maldonado, Ivana; Gutkind, Gabriel O; Radice, Marcela A

2014-09-01

KPC-2-producing Klebsiella pneumoniae isolates mainly correspond to clonal complex 258 (CC258); however, we describe KPC-2-producing K. pneumoniae isolates belonging to invasive sequence type 23 (ST23). KPC-2 has scarcely been reported to occur in ST23, and this report describes the first isolation of this pathogen in the Americas. Acquisition of resistant markers in virulent clones could mark an evolutionary step toward the establishment of these clones as major nosocomial pathogens. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Putative Virulence Factor Expression by Clinical and Food Isolates of Bacillus spp. after Growth in Reconstituted Infant Milk Formulae

PubMed Central

Rowan, Neil J.; Deans, Karen; Anderson, John G.; Gemmell, Curtis G.; Hunter, Iain S.; Chaithong, Thararat

2001-01-01

Forty-seven strains representing 14 different Bacillus species isolated from clinical and food samples were grown in reconstituted infant milk formulae (IMF) and subsequently assessed for adherence to, invasion of, and cytotoxicity toward HEp-2 and Caco-2 cells. Cell-free supernatant fluids from 38 strains (81%) were shown to be cytotoxic, 43 strains (91%) adhered to the test cell lines, and 23 strains (49%) demonstrated various levels of invasion. Of the 21 Bacillus cereus strains examined, 5 (24%) were invasive. A larger percentage of clinically derived Bacillus species (20%) than of similar species tested from the food environment were invasive. Increased invasion occurred after growth of selected Bacillus species in reconstituted IMF containing glucose. While PCR primer studies revealed that many different Bacillus species contained DNA sequences encoding the hemolysin BL (HBL) enterotoxin complex and B. cereus enterotoxin T, not all of these isolates expressed these diarrheagenic genes after growth in reconstituted IMF. Of the 47 Bacillus isolates examined, 3 isolates of B. cereus and 1 isolate of B. subtilis produced the HBL enterotoxin after 18 h of growth in brain heart infusion broth. However, eight isolates belonging to the species B. cereus, B. licheniformis, B. circulans, and B. megaterium were found to produce this enterotoxin after growth in reconstituted IMF when assessed with the B. cereus enterotoxin (diarrheal type) reversed passive latex agglutination (RPLA) kit. It is concluded that several Bacillus species occurring occasionally in clinical specimens and food samples are of potential medical significance due to the expression of putative virulence factors. PMID:11525980

Proteogenomic Investigation of Strain Variation in Clinical Mycobacterium tuberculosis Isolates.

PubMed

Heunis, Tiaan; Dippenaar, Anzaan; Warren, Robin M; van Helden, Paul D; van der Merwe, Ruben G; Gey van Pittius, Nicolaas C; Pain, Arnab; Sampson, Samantha L; Tabb, David L

2017-10-06

Mycobacterium tuberculosis consists of a large number of different strains that display unique virulence characteristics. Whole-genome sequencing has revealed substantial genetic diversity among clinical M. tuberculosis isolates, and elucidating the phenotypic variation encoded by this genetic diversity will be of the utmost importance to fully understand M. tuberculosis biology and pathogenicity. In this study, we integrated whole-genome sequencing and mass spectrometry (GeLC-MS/MS) to reveal strain-specific characteristics in the proteomes of two clinical M. tuberculosis Latin American-Mediterranean isolates. Using this approach, we identified 59 peptides containing single amino acid variants, which covered ∼9% of all coding nonsynonymous single nucleotide variants detected by whole-genome sequencing. Furthermore, we identified 29 distinct peptides that mapped to a hypothetical protein not present in the M. tuberculosis H37Rv reference proteome. Here, we provide evidence for the expression of this protein in the clinical M. tuberculosis SAWC3651 isolate. The strain-specific databases enabled confirmation of genomic differences (i.e., large genomic regions of difference and nonsynonymous single nucleotide variants) in these two clinical M. tuberculosis isolates and allowed strain differentiation at the proteome level. Our results contribute to the growing field of clinical microbial proteogenomics and can improve our understanding of phenotypic variation in clinical M. tuberculosis isolates.

Molecular Characterization of Shiga Toxin-Producing Escherichia coli Strains Isolated in Poland.

PubMed

Januszkiewicz, Aleksandra; Rastawicki, Waldemar

2016-08-26

Shiga toxin-producing Escherichia coli (STEC) strains also called verotoxin-producing E. coli (VTEC) represent one of the most important groups of food-borne pathogens that can cause several human diseases such as hemorrhagic colitis (HC) and hemolytic - uremic syndrome (HUS) worldwide. The ability of STEC strains to cause disease is associated with the presence of wide range of identified and putative virulence factors including those encoding Shiga toxin. In this study, we examined the distribution of various virulence determinants among STEC strains isolated in Poland from different sources. A total of 71 Shiga toxin-producing E. coli strains isolated from human, cattle and food over the years 1996-2010 were characterized by microarray and PCR detection of virulence genes. As stx1a subtype was present in all of the tested Shiga toxin 1 producing E. coli strains, a greater diversity of subtypes was found in the gene stx2, which occurred in five subtypes: stx2a, stx2b, stx2c, stx2d, stx2g. Among STEC O157 strains we observed conserved core set of 14 virulence factors, stable in bacteria genome at long intervals of time. There was one cattle STEC isolate which possessed verotoxin gene as well as sta1 gene encoded heat-stable enterotoxin STIa characteristic for enterotoxigenic E. coli. To the best of our knowledge, this is the first comprehensive analysis of virulence gene profiles identified in STEC strains isolated from human, cattle and food in Poland. The results obtained using microarrays technology confirmed high effectiveness of this method in determining STEC virulotypes which provides data suitable for molecular risk assessment of the potential virulence of this bacteria. virulence factors including those encoding Shiga toxin. In this study, we examined the distribution of various virulence determinants among STEC strains isolated in Poland from different sources. A total of 71 Shiga toxin-producing E. coli strains isolated from human, cattle and food over

Genetic Platforms of blaCTX-M in Carbapenemase-Producing Strains of K. pneumoniae Isolated in Chile

PubMed Central

Carrasco-Anabalón, Sergio; Vera-Leiva, Alejandra; Quezada-Aguiluz, Mario; Morales-Rivera, María F.; Lima, Celia A.; Fernández, Jorge; Ulloa, Soledad; Domínguez, Mariana; González-Rocha, Gerardo; Bello-Toledo, Helia

2018-01-01

Objective: To elucidate whether the genetic platforms of blaCTX-M contribute to the phenotypes of multi-drug-resistance (MDR) in the first carbapenemase-producing K. pneumoniae strains isolated in Chile. Method: Twenty-two carbapenemase-producing K. pneumoniae strains isolated from different Chilean patients and hospitals were studied. Their genetic relatedness was assessed by PFGE and MLST. The levels of antibiotic resistance were evaluated by determining the minimum inhibitory concentration of various antimicrobials. In addition, several antibiotic resistance genes of clinical relevance in Chile were investigated. The prevalence, allelic variants, and genetic platforms of blaCTX-M were determined by PCR and sequencing. Results: Out of the 22 strains studied, 20 carry KPC, one carries NDM-1, and one carries OXA-370. The PFGE analysis showed three clades with a genetic relatedness >85%, two formed by four strains and one by eight strains. The other strains are not genetically related, and a total of 17 different pulse types were detected. Ten different STs were identified, the main ones being ST258 (five strains) and ST1161 (seven strains). The isolates presented different percentages of resistance, and 82% were resistant to all the β-lactams tested, 91% to ciprofloxacin, 73% to colistin, 59% to gentamicin, 50% to amikacin, and only 9% to tigecycline. All isolates carried blaTEM and blaSHV, whereas 71% carried aac(6′)Ib-cr, and 57% one qnr gene (A, B, C, D, or S). The blaCTX-M gene was found in 10 of the isolates (4 blaCTX-M−15 and 6 blaCTX-M−2). The characterization of the platform, in seven selected strains, revealed that the gene is associated with unusual class 1 integrons and insertion sequences such as ISCR1, ISECp1, and IS26. Conclusion: In the first carbapenemase-producing K. pneumoniae strains isolated in Chile the genetic platform of blaCTX-M−2 corresponds to an unusual class 1 integron that can be responsible for the MDR phenotype, whereas the

Clinical MRSA isolates from skin and soft tissue infections show increased in vitro production of phenol soluble modulins

PubMed Central

Berlon, Nicholas R.; Qi, Robert; Sharma-Kuinkel, Batu K.; Joo, Hwang-Soo; Park, Lawrence P.; George, Dennis; Thaden, Joshua T.; Messina, Julia A.; Maskarinec, Stacey A.; Mueller-Premru, Manica; Athan, Eugene; Tattevin, Pierre; Pericas, Juan M.; Woods, Christopher W.; Otto, Michael; Fowler, Vance G.

2016-01-01

Summary Background Phenol-soluble modulins (PSMs) are amphipathic, pro-inflammatory proteins secreted by most Staphylococcus aureus isolates. This study tested the hypothesis that in vitro PSM production levels are associated with specific clinical phenotypes. Methods 177 methicillin-resistant S. aureus (MRSA) isolates from infective endocarditis (IE), skin and soft tissue infection (SSTI), and hospital-acquired/ventilator-associated pneumonia (HAP) were matched by geographic origin, then genotyped using spa-typing. In vitro PSM production was measured by high performance liquid chromatography/mass spectrometry. Statistical analysis was performed using Chi-squared or Kruskal–Wallis tests as appropriate. Results Spa type 1 was significantly more common in SSTI isolates (62.7% SSTI; 1.7% IE; 16.9% HAP; p < 0.0001) while HAP and IE isolates were more commonly spa type 2 (0% SSTI; 37.3% IE; 40.7% HAP; p < 0.0001). USA300 isolates produced the highest levels of PSMs in vitro. SSTI isolates produced significantly higher quantities of PSMα1-4, PSMβ1, and δ-toxin than other isolates (p < 0.001). These findings persisted when USA300 isolates were excluded from analysis. PMID:26079275

Characterization of Vancomycin-Resistant Enterococcus faecalis and Enterococcus faecium Isolated from Fresh Produces and Human Fecal Samples.

PubMed

Kim, Min-Chan; Cha, Min-Hyeok; Ryu, Jae-Gee; Woo, Gun-Jo

2017-04-01

Increased enterococcal infections in hospitals and multidrug-resistant and vancomycin-resistant enterococci (VRE) isolated from humans, animals, and food sources raised public health concern on the presence of VRE in multiple sources. We performed a comparative analysis of the antimicrobial resistance and genetics of VRE isolates derived from fresh produce and human fecal samples. Of 389 Enterococcus isolates, 8 fecal and 3 produce isolates were resistant to vancomycin and teicoplanin; all harbored vanA gene. The VRE isolates showed multidrug-resistant properties. The isolates from fresh produce in this study showed to have the common shared characteristics with the isolates from humans by the results of antimicrobial resistance, multilocus sequence typing, and Tn 1546 transposon analysis. Therefore, VRE isolates from fresh produce are likely related to VRE derived from humans. The results suggested that VRE may contaminate vegetables through the environment, and the contaminated vegetables could then act as a vehicle for human infections. Ongoing nationwide surveillance of antibiotic resistance and the promotion of the proper use of antibiotics are necessary.

Comparison of Meropenem MICs and Susceptibilities for Carbapenemase-Producing Klebsiella pneumoniae Isolates by Various Testing Methods▿

PubMed Central

Bulik, Catharine C.; Fauntleroy, Kathy A.; Jenkins, Stephen G.; Abuali, Mayssa; LaBombardi, Vincent J.; Nicolau, David P.; Kuti, Joseph L.

2010-01-01

We describe the levels of agreement between broth microdilution, Etest, Vitek 2, Sensititre, and MicroScan methods to accurately define the meropenem MIC and categorical interpretation of susceptibility against carbapenemase-producing Klebsiella pneumoniae (KPC). A total of 46 clinical K. pneumoniae isolates with KPC genotypes, all modified Hodge test and blaKPC positive, collected from two hospitals in NY were included. Results obtained by each method were compared with those from broth microdilution (the reference method), and agreement was assessed based on MICs and Clinical Laboratory Standards Institute (CLSI) interpretative criteria using 2010 susceptibility breakpoints. Based on broth microdilution, 0%, 2.2%, and 97.8% of the KPC isolates were classified as susceptible, intermediate, and resistant to meropenem, respectively. Results from MicroScan demonstrated the most agreement with those from broth microdilution, with 95.6% agreement based on the MIC and 2.2% classified as minor errors, and no major or very major errors. Etest demonstrated 82.6% agreement with broth microdilution MICs, a very major error rate of 2.2%, and a minor error rate of 2.2%. Vitek 2 MIC agreement was 30.4%, with a 23.9% very major error rate and a 39.1% minor error rate. Sensititre demonstrated MIC agreement for 26.1% of isolates, with a 3% very major error rate and a 26.1% minor error rate. Application of FDA breakpoints had little effect on minor error rates but increased very major error rates to 58.7% for Vitek 2 and Sensititre. Meropenem MIC results and categorical interpretations for carbapenemase-producing K. pneumoniae differ by methodology. Confirmation of testing results is encouraged when an accurate MIC is required for antibiotic dosing optimization. PMID:20484603

[Isolation, identification and characterization of acid-producing strains from psychrotolerant biogas fermentation].

PubMed

Wan, Yongqing; Zhang, Wei; Mandlaa; Tian, Ruihua; Wang, Ruigang; Duan, Kaihong

2015-11-04

The aim of this study was to screen acid-producing strains from the broth of psychrotolerant biogas fermentation and evaluate the acid-producing character of them. Acid-producing strains were isolated by a medium with methyl red at 4 degrees C in Petri dishes and identified by morphology observation and 16S rRNA sequencing. Moreover, the ability of hydrolysis of starch, fermentation of carbohydrates, liquefaction of gelatin and production of catalase were studied. Two acid-producing strains (FJ-8 and FJ-15) were isolated. The result of the 16S rRNA phylogenetic tree shows that FJ-8 and FJ-15 belong to Pseudomonas sp. and Shewanella sp., respectively. Both FJ-8 and FJ-15 could hydrolyze starch, liquidize gelatin and produce catalase. The optimum temperature for acid-producing of FJ-8 and FJ-15 is 15 degrees C and 20 degrees C, respectively. After 10 days cultivation at 4 degrees C, the concentration of acetic acid was 792 mg/L and 966 mg/L of FJ-8 and FJ-15, respectively. The selected strains, FJ-8 and FJ-15, have the potential to produce acids at low temperature.

Epidemiology, Clinical Characteristics, and Antimicrobial Susceptibility Profiles of Human Clinical Isolates of Staphylococcus intermedius Group.

PubMed

Yarbrough, Melanie L; Lainhart, William; Burnham, C A

2018-03-01

The veterinary pathogens in the Staphylococcus intermedius group (SIG) are increasingly recognized as causes of human infection. Shared features between SIG and Staphylococcus aureus may result in the misidentification of SIG in human clinical cultures. This study examined the clinical and microbiological characteristics of isolates recovered at a tertiary-care academic medical center. From 2013 to 2015, 81 SIG isolates were recovered from 62 patients. Patients were commonly ≥50 years old, diabetic, and/or immunocompromised. Documentation of dog exposure in the electronic medical record was not common. Of the 81 SIG isolates, common sites of isolation included 37 (46%) isolates from wound cultures and 17 (21%) isolates from respiratory specimens. Although less common, 10 (12%) bloodstream infections were documented in 7 unique patients. The majority of SIG (65%) isolates were obtained from polymicrobial cultures. In comparison to S. aureus isolates from the same time period, significant differences were noted in proportion of SIG isolates that were susceptible to doxycycline (74% versus 97%, respectively; P < 0.001), trimethoprim-sulfamethoxazole (65% versus 97%, respectively; P < 0.001), and ciprofloxacin (78% versus 59%, respectively; P < 0.01). Methicillin resistance (MR) was detected in 12 (15%) of 81 SIG isolates. All MR isolates detected by an oxacillin disk diffusion test would have been misclassified as methicillin susceptible using a cefoxitin disk diffusion test. Thus, SIG is recovered from human clinical specimens, and distinction of SIG from S. aureus is critical for the accurate characterization of MR status in these isolates. Copyright © 2018 American Society for Microbiology.

Clonal distribution and associated characteristics of Escherichia coli clinical and surveillance isolates from a military medical center.

PubMed

Manges, Amee R; Mende, Katrin; Murray, Clinton K; Johnston, Brian D; Sokurenko, Evgeni V; Tchesnokova, Veronika; Johnson, James R

2017-04-01

Antimicrobial-resistant Escherichia coli are a concern for military health services. We studied 100 extended-spectrum beta-lactamase (ESBL)-producing and non-producing E. coli clinical and surveillance isolates from military personnel and civilians at Brooke Army Medical Center (2007-2011). Major E. coli lineages, most prominently ST10 (24%), ST131 (16%), and ST648 (8%), were distributed much as reported for other North American populations. ST131, represented mainly by its resistance-associated ST131-H30 clonal subset, was uniquely associated with a clinical origin, regardless of ESBL status. Thus, clonal background predicted resistance phenotype and clinical versus surveillance origin, and these findings could assist military clinicians and epidemiologists. Published by Elsevier Inc.

The Role of OmpK35, OmpK36 Porins, and Production of β-Lactamases on Imipenem Susceptibility in Klebsiella pneumoniae Clinical Isolates, Cairo, Egypt.

PubMed

Wassef, Mona; Abdelhaleim, Mona; AbdulRahman, Eiman; Ghaith, Doaa

2015-12-01

OmpK35 and OmpK36 are the major outer membrane porins of Klebsiella pneumoniae. We aimed to study the effect of combined porin loss and production of extended-spectrum β-lactamases (ESBLs) on imipenem susceptibility among K. pneumoniae clinical isolates. This study included 91 suspected ESBL-producing K. pneumoniae clinical isolates, isolated from different patient specimens at the Cairo University hospital from January to June 2010. All isolates were subjected to genotypic analysis of the outer membrane protein gene expression using reverse transcription-PCR (RT-PCR) and analysis of OmpK35/36 of 38 isolates by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). By RT-PCR, loss of Omp35 was detected in 78 (85.7%) isolates, loss of Omp36 was detected in 64 (70.32%), and loss of both porins was detected in 62 (68.1%). Out of 91 isolates, 45 (49.5%) were resistant to cefoxitin, and 17 (18.7%) were confirmed as derepressed AmpC producers. Omp35 was lost in all FOX-resistant isolates, whereas Omp36 was lost in 42 (93.3%) (p-value 0.002). The mean of ceftazidime inhibition zone diameter was significantly decreased among ESBL-producing isolates with loss of Omp35/36 (p-value 0.041 and 0.006), respectively. The mean of imipenem minimal inhibitory concentration (MIC) was markedly increased to 8.55 μg/ml among AmpC-producing isolates with Omp35/36 loss, while the mean of imipenem MIC among the 66 confirmed ESBL producers was 0.32 μg/ml. Imipenem MIC was markedly increased among K. pneumoniae isolates showing AmpC production with loss of both porins OmpK35/36. Meanwhile, the association of porin OmpK35/36 loss with ESBL production was not a direct cause of resistance to imipenem.

Characterization of biofilms produced by Escherichia coli O157 isolated from cattle hides

NASA Astrophysics Data System (ADS)

Milojević, L.; Velebit, B.; Baltić, T.; Nikolić, A.; Mitrović, R.; Đorđević, V.

2017-09-01

This study aimed to investigate possibility E. coli O157 from cattle hides to produced biofilms. We had 28 suspect primoisolates and 17 were confirmed to be E. coli O157. Biofilm production test showed that more than 50% of this isolates did not produce biofilm. From the other half of the isolates, 5 of them were weakly adherent, 3 were moderately adherent. Since E. coli O157 are one of the main foodborne hazards in meat processing industry and the discovery that some of them can produce moderately adherent biofilms, request necessity of strict implementation of HACCP procedures to prevent further expansion this pathogen.

Prevalence of Shiga toxin-producing Shigella species isolated from French travellers returning from the Caribbean: an emerging pathogen with international implications.

PubMed

Gray, M D; Lacher, D W; Leonard, S R; Abbott, J; Zhao, S; Lampel, K A; Prothery, E; Gouali, M; Weill, F-X; Maurelli, A T

2015-08-01

Shiga toxins (Stxs) are potent cytotoxins that inhibit host cell protein synthesis, leading to cell death. Classically, these toxins are associated with intestinal infections due to Stx-producing Escherichia coli or Shigella dysenteriae serotype 1, and infections with these strains can lead to haemolytic-uraemic syndrome. Over the past decade, there has been increasing recognition that Stx is produced by additional Shigella species. We recently reported the presence and expression of stx genes in Shigella flexneri 2a clinical isolates. The toxin genes were carried by a new stx-encoding bacteriophage, and infection with these strains correlated with recent travel to Haiti or the Dominican Republic. In this study, we further explored the epidemiological link to this region by utilizing the French National Reference Centre for Escherichia coli, Shigella and Salmonella collection to survey the frequency of Stx-producing Shigella species isolated from French travellers returning from the Caribbean. Approximately 21% of the isolates tested were found to encode and produce Stx. These isolates included strains of S. flexneri 2a, S. flexneri Y, and S. dysenteriae 4. All of the travellers who were infected with Stx-producing Shigella had recently travelled to Haiti, the Dominican Republic, or French Guiana. Furthermore, whole genome sequencing showed that the toxin genes were encoded by a prophage that was highly identical to the phage that we identified in our previous study. These findings demonstrate that this new stx-encoding prophage is circulating within that geographical area, has spread to other continents, and is capable of spreading to multiple Shigella serogroups. Published by Elsevier Ltd.

Herpes Simplex Virus Type 2 Glycoprotein G-Negative Clinical Isolates Are Generated by Single Frameshift Mutations

PubMed Central

Liljeqvist, Jan-Åke; Svennerholm, Bo; Bergström, Tomas

1999-01-01

Herpes simplex virus (HSV) codes for several envelope glycoproteins, including glycoprotein G-2 (gG-2) of HSV type 2 (HSV-2), which are dispensable for replication in cell culture. However, clinical isolates which are deficient in such proteins occur rarely. We describe here five clinical HSV-2 isolates which were found to be unreactive to a panel of anti-gG-2 monoclonal antibodies and therefore considered phenotypically gG-2 negative. These isolates were further examined for expression of the secreted amino-terminal and cell-associated carboxy-terminal portions of gG-2 by immunoblotting and radioimmunoprecipitation. The gG-2 gene was completely inactivated in four isolates, with no expression of the two protein products. For one isolate a normally produced secreted portion and a truncated carboxy-terminal portion of gG-2 were detected in virus-infected cell medium. Sequencing of the complete gG-2 gene identified a single insertion or deletion of guanine or cytosine nucleotides in all five strains, resulting in a premature termination codon. The frameshift mutations were localized within runs of five or more guanine or cytosine nucleotides and were dispersed throughout the gene. For the isolate for which a partially inactivated gG-2 gene was detected, the frameshift mutation was localized upstream of but adjacent to the nucleotides coding for the transmembranous region. Thus, this study demonstrates the existence of clinical HSV-2 isolates which do not express an envelope glycoprotein and identifies the underlying molecular mechanism to be a single frameshift mutation. PMID:10559290

Draft Genome Sequence of the First New Delhi Metallo-β-Lactamase (NDM-1)-Producing Escherichia coli Strain Isolated in Peru.

PubMed

Tamariz, Jesus; Llanos, Carlos; Seas, Carlos; Montenegro, Paola; Lagos, Jose; Fernandes, Miriam R; Cerdeira, Louise; Lincopan, Nilton

2018-03-29

We present here the draft genome sequence of the first New Delhi metallo-β-lactamase (NDM-1)-producing Escherichia coli strain, belonging to sequence type 155 (ST155), isolated in Peru. Assembly of this draft genome resulted in 5,061,184 bp, revealing a clinically significant resistome for β-lactams, aminoglycosides, tetracyclines, phenicols, sulfonamides, trimethoprim, and fluoroquinolones. Copyright © 2018 Tamariz et al.

Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli isolates collected from diseased food-producing animals in the GERM-Vet monitoring program 2008-2014.

PubMed

Michael, Geovana Brenner; Kaspar, Heike; Siqueira, Amanda Keller; de Freitas Costa, Eduardo; Corbellini, Luís Gustavo; Kadlec, Kristina; Schwarz, Stefan

2017-02-01

The aim of this study was to identify extended-spectrum β-lactamase (ESBL)-producing Escherichia coli collected from diseased food-producing animals in Germany. A total of 6849 E. coli isolates, collected from diseased cattle, pigs and poultry in the German national monitoring program GERM-Vet (2008-2014), were characterized by antimicrobial susceptibility testing and screened for the ESBL phenotype. ESBL genes were identified by PCR and sequencing. The isolates were further characterized by PCR-based phylotyping. The 419/6849 (6.1%) ESBL-producers identified included 324/2896 (11.2%) isolates from cattle, 75/1562 (4.8%) from pigs and 20/2391 (0.8%) from poultry. The ESBL genes detected were: bla CTX-M-1 (69.9%), bla CTX-M-15 (13.6%), bla CTX-M-14 (11.7%), bla TEM-52 (1.9%), bla SHV-12 (1.4%), bla CTX-M-3 (1.0%), and bla CTX-M-2 (0.5%). The phylogroup A was the dominant phylogroup (57.0%) followed by phylogroups D (23.4%), B1 (17.9%), and B2 (1.7%). Bovine isolates belonged predominantly to the phylogroups A and D, whereas the porcine and avian isolates mainly belonged to A and B1. The majority of the ESBL-producing isolates found in each phylogroup were from animals suffering from gastrointestinal infections. In 399/419 isolates (95.2%), additional resistance to non-β-lactam antibiotics was seen. Multidrug-resistance [resistance to aminoglycosides, fluoro(quinolones), sulphonamides, tetracyclines, and trimethoprim] was seen in 369/419 (88.1%) isolates, which may facilitate the co-selection of ESBL genes, when located on the same mobile genetic element as the others resistance genes, and may compromise the therapeutic options. Copyright © 2016 Elsevier B.V. All rights reserved.

Clinical and molecular epidemiology of chromosome-mediated resistance to third-generation cephalosporins in Enterobacter isolates in eastern France.

PubMed

Talon, D; Bailly, P; Bertrand, X; Thouverez, M; Mulin, B

2000-07-01

To determine both the prevalence of group I beta-lactamase-related resistance and the clinical setting in which resistance to expanded-spectrum cephalosporins occurs. Isolates of Enterobacter spp. were sensitivity tested to a range of antibiotics, and selected isolates were DNA fingerprinted by pulsed-field gel electrophoresis. The medical records of all patients with positive cultures for Enterobacter spp. were reviewed to determine the effect of previous antibiotic treatment on the susceptibility profile of these organisms. The crude incidence of colonization/infection (n = 315) was 0.51 per 100 patients and 0.73 per 1000 days of hospitalization. The 4-day and 7-day Kaplan-Meier rates of colonization/infection with Enterobacter were estimated to be 7.57% (standard deviation (SD = 3.26%) and 4.16% (SD = 2.88%)), respectively. The time lag to colonization/infection with isolates producing large amounts of Bush group 1 beta-lactamase (HLBL) (27.35 +/- 27.30 days) was significantly different from that to colonization/infection with wild-type isolates (13.59 +/- 17.93 days) (P = 0.036). Ninety-six isolates (30.5%) demonstrated acquired resistance to expanded-spectrum cephalosporins: 34 isolates (10.8%) produced extended-spectrum beta-lactamase, and 62 isolates (19.7%) produced HLBL. The 89 Enterobacter isolates susceptible to third-generation cephalosporins yielded 84 major DNA patterns, and the 45 HLBL isolates yielded 38 major DNA patterns. The risk of colonization/infection with HLBL-producing Enterobacter was higher in cases of antimicrobial treatment with third-generation cephalosporins or a fluoroquinolone, and in cases of urinary tract colonization/infection. The judicious use in hospitals of both expanded-spectrum cephalosporins and other antibiotics such as fluoroquinolones is necessary to curtail the emergence of resistance in Enterobacter spp.

Isolation of mesophilic solvent-producing clostridia from Colombian sources: physiological characterization, solvent production and polysaccharide hydrolysis.

PubMed

Montoya, D; Spitia, S; Silva, E; Schwarz, W H

2000-04-28

One hundred and seventy-eight new butanol-acetone producing bacteria related to saccharolytic clostridia were isolated from agricultural sources in Colombia and their fermentation potential was evaluated. Thirteen isolates produced more total solvents from glucose than Clostridium acetobutylicum ATCC 824. The isolates with the highest single solvent production were IBUN 125C and IBUN 18A with 0.46 mol butanol and 0.96 mol ethanol formed from 1 mol glucose, yielding 25. 2 and 29.1 g l(-1) total solvents, respectively, which is close to the maximum values described to date. Most of the new isolates produced exoenzymes for the hydrolysis of starch, carboxymethyl cellulose, xylan, polygalacturonic acid, inulin and chitosan. Together with the high efficiency of solvent production, these hydrolytic isolates may be useful for the direct fermentation of biomass. According to their physiological profile, the most solvent-productive isolates could be classified as strains of C. acetobutylicum, Clostridium beijerinckii, and Clostridium NCP262.

Microbiological Features of KPC-Producing Enterobacter Isolates Identified in a U.S. Hospital System

PubMed Central

Ahn, Chulsoo; Syed, Alveena; Hu, Fupin; O’Hara, Jessica A.; Rivera, Jesabel I.; Doi, Yohei

2014-01-01

Microbiological data regarding KPC-producing Enterobacter spp. are scarce. In this study, 11 unique KPC-producing Enterobacter isolates were identified among 44 ertapenem-non-susceptible Enterobacter isolates collected between 2009 and 2013 at a hospital system in Western Pennsylvania. All cases were healthcare-associated and occurred in medically complex patients. While pulsed-field gel electrophoresis (PFGE) showed diverse restriction patterns overall, multilocus sequence typing (MLST) identified Enterobacter cloacae isolates with sequence types (STs) 93 and 171 from two hospitals each. The levels of carbapenem minimum inhibitory concentrations were highly variable. All isolates remained susceptible to colistin, tigecycline, and the majority to amikacin and doxycycline. A blaKPC-carrying IncN plasmid conferring trimethoprim-sulfamethoxazole resistance was identified in three of the isolates. Spread of blaKPC in Enterobacter spp. appears to be due to a combination of plasmid-mediated and clonal processes. PMID:25053203

Massilia sp. BS-1, a novel violacein-producing bacterium isolated from soil.

PubMed

Agematu, Hitosi; Suzuki, Kazuya; Tsuya, Hiroaki

2011-01-01

A novel bacterium, Massilia sp. BS-1, producing violacein and deoxyviolacein was isolated from a soil sample collected from Akita Prefecture, Japan. The 16S ribosomal DNA of strain BS-1 displayed 93% homology with its nearest violacein-producing neighbor, Janthinobacterium lividum. Strain BS-1 grew well in a synthetic medium, but required both L-tryptophan and a small amount of L-histidine to produce violacein.

Phenotypic and genotypic profile of clinical and animal multidrug-resistant Salmonella enterica isolates from Mexico.

PubMed

Aguilar-Montes de Oca, S; Talavera-Rojas, M; Soriano-Vargas, E; Barba-León, J; Vázquez-Navarrete, J; Acosta-Dibarrat, J; Salgado-Miranda, C

2018-01-01

The objective of this study was to obtain a phenotypic and genotypic profile of Salmonella enterica including multidrug-resistant (MDR) isolates from food-producing animals and clinical isolates, as well as their genetic relatedness in two different States of Mexico (Jalisco and State of Mexico). A total of 243 isolates were evaluated in terms of antimicrobial resistance (AMR) and related genes through a disk diffusion method and PCR respectively; we found 16 MDR isolates, all of them harbouring the bla CMY gene but not qnr genes, these isolates represent less than 10% of the collection. The pulsed-field gel electrophoresis revealed a higher genotypic similitude within isolates of State of Mexico than Jalisco. A low percentage of Salmonella isolates were resistant to relevant antibiotics in human health, nevertheless, the AMR and involved genes were similar despite the different serovars and origin of the isolates. This investigation provided an insight of the current status of AMR of Salmonella isolates in two States of Mexico and pinpoint the genes involved in AMR and their epidemiological relationship, the information could help to determine an adequate therapy in human and veterinary medicine. © 2017 The Society for Applied Microbiology.

Isolation and Characterization of Saponin-Producing Fungal Endophytes from Aralia elata in Northeast China

PubMed Central

Wu, Hao; Yang, Hongyan; You, Xiangling; Li, Yuhua

2012-01-01

The purpose of this study was to investigate the diversity of endophytic fungi of Aralia elata distributed in Northeast China as well as their capacity to produce saponins. Ninety-six strains of endophytic fungi were isolated, and polymerase chain reaction (PCR) and sequencing were employed to identify the isolates. The saponin concentrations of the culture filtrates of representative strains were measured. The agar diffusion method was used to test antimicrobial activity, while high-performance liquid chromatography (HPLC) was employed to identify the saponins produced by representative strains. Alternaria, Botryosphaeria, Camarosporium, Cryptosporiopsis, Diaporthe, Dictyochaeta, Penicillium, Fusarium, Nectria, Peniophora, Schizophyllum, Cladosporium and Trichoderma species were isolated in this study. Overall, 25% of the isolates belonged to Diaporthe (Diaporthe eres), and 12.5% belonged to Alternaria. The highest concentration of saponins was produced by G22 (2.049 mg/mL). According to the results of the phylogenetic analysis, G22 belonged to the genus Penicillium. The culture filtrate of G22 exhibited antibacterial activity against Staphylococcus aureus, and ginsenosides Re and Rb2 were detected in G22 culture filtrates by HPLC. PMID:23203194

Isolation and clinical sample typing of human leptospirosis cases in Argentina.

PubMed

Chiani, Yosena; Jacob, Paulina; Varni, Vanina; Landolt, Noelia; Schmeling, María Fernanda; Pujato, Nazarena; Caimi, Karina; Vanasco, Bibiana

2016-01-01

Leptospira typing is carried out using isolated strains. Because of difficulties in obtaining them, direct identification of infective Leptospira in clinical samples is a high priority. Multilocus sequence typing (MLST) proved highly discriminatory for seven pathogenic species of Leptospira, allowing isolate characterization and robust assignment to species, in addition to phylogenetic evidence for the relatedness between species. In this study we characterized Leptospira strains circulating in Argentina, using typing methods applied to human clinical samples and isolates. Phylogenetic studies based on 16S ribosomal RNA gene sequences enabled typing of 8 isolates (6 Leptospira interrogans, one Leptospira wolffii and one Leptospira broomii) and 58 out of 85 (68.2%) clinical samples (55 L. interrogans, 2 Leptospira meyeri, and one Leptospira kirschneri). MLST results for the L. interrogans isolates indicated that five were probably Canicola serogroup (ST37) and one was probably Icterohaemorrhagiae serogroup (ST17). Eleven clinical samples (21.6%), provided MLST interpretable data: five were probably Pyrogenes serogroup (ST13), four Sejroe (ST20), one Autumnalis (ST22) and one Canicola (ST37). To the best of our knowledge this study is the first report of the use of an MLST typing scheme with seven loci to identify Leptospira directly from clinical samples in Argentina. The use of clinical samples presents the advantage of the possibility of knowing the infecting strain without resorting to isolates. This study also allowed, for the first time, the characterization of isolates of intermediate pathogenicity species (L. wolffii and L. broomii) from symptomatic patients. Copyright © 2015 Elsevier B.V. All rights reserved.

Isolation of histamine-producing Lactobacillus buchneri from Swiss cheese implicated in a food poisoning outbreak.

PubMed Central

Sumner, S S; Speckhard, M W; Somers, E B; Taylor, S L

1985-01-01

A histamine-producing strain of Lactobacillus buchneri was isolated from Swiss cheese that had been implicated in an outbreak of histamine poisoning. It produced up to 4,070 nmol of histamine per ml in MRS broth supplemented with 0.1% histidine. The identification of this isolate was based on its biochemical, bacteriological, and DNA characterizations. PMID:4083875

Sambutoxin, a new mycotoxin produced by toxic Fusarium isolates obtained from rotted potato tubers.

PubMed Central

Kim, J C; Lee, Y W

1994-01-01

Ninety-nine isolates of Fusarium species were obtained from rotted potato tubers from various parts of Korea. Of these isolates, 80 were identified as Fusarium oxysporum, F. solani, or F. sambucinum. The isolates of these species were grown on autoclaved wheat grains and examined for toxicity in a rat-feeding test. A total of 8 of 57 F. oxysporum isolates, 3 of 14 F. solani isolates, and 5 of 9 F. sambucinum isolates caused the death of the rats. Of the 16 toxic isolates, 1 isolate of F. oxysporum produced a substantial amount of moniliformin, which could account for its toxicity. None of the other 15 isolates produced trichothecenes, moniliformin, fusarochromanone, fumonisin B1, or wortmannin. F. sambucinum PZF-4 produced an unknown toxin in wheat culture. This new toxin, given the trivial name sambutoxin, caused toxic effects in rats, including body weight loss, feed refusal, hemorrhage in the stomach and intestines, and, finally, death when rats were fed diets supplemented with 0.05 and 0.1% sambutoxin. The toxin was also toxic to chicken embryos, and the 50% lethal concentration was 29.6 micrograms per egg. Sambutoxin formed as white crystals that turned purple when combined with reagents such as sulfuric acid and p-anisaldehyde. It exhibited a green color immediately after treatment with potassium ferricyanide-ferric chloride. Its UV spectrum had absorption maxima at 213, 233, and 254 nm, and its infrared spectrum showed an amide group at 1,650 and 1,560 cm-1 and a hydroxy group at 3,185 cm-1. Mass spectrometry showed that the molecular weight of the toxin was 453 and the molecular formula was C28H39NO4.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7811078

Sambutoxin, a new mycotoxin produced by toxic Fusarium isolates obtained from rotted potato tubers.

PubMed

Kim, J C; Lee, Y W

1994-12-01

Ninety-nine isolates of Fusarium species were obtained from rotted potato tubers from various parts of Korea. Of these isolates, 80 were identified as Fusarium oxysporum, F. solani, or F. sambucinum. The isolates of these species were grown on autoclaved wheat grains and examined for toxicity in a rat-feeding test. A total of 8 of 57 F. oxysporum isolates, 3 of 14 F. solani isolates, and 5 of 9 F. sambucinum isolates caused the death of the rats. Of the 16 toxic isolates, 1 isolate of F. oxysporum produced a substantial amount of moniliformin, which could account for its toxicity. None of the other 15 isolates produced trichothecenes, moniliformin, fusarochromanone, fumonisin B1, or wortmannin. F. sambucinum PZF-4 produced an unknown toxin in wheat culture. This new toxin, given the trivial name sambutoxin, caused toxic effects in rats, including body weight loss, feed refusal, hemorrhage in the stomach and intestines, and, finally, death when rats were fed diets supplemented with 0.05 and 0.1% sambutoxin. The toxin was also toxic to chicken embryos, and the 50% lethal concentration was 29.6 micrograms per egg. Sambutoxin formed as white crystals that turned purple when combined with reagents such as sulfuric acid and p-anisaldehyde. It exhibited a green color immediately after treatment with potassium ferricyanide-ferric chloride. Its UV spectrum had absorption maxima at 213, 233, and 254 nm, and its infrared spectrum showed an amide group at 1,650 and 1,560 cm-1 and a hydroxy group at 3,185 cm-1. Mass spectrometry showed that the molecular weight of the toxin was 453 and the molecular formula was C28H39NO4.(ABSTRACT TRUNCATED AT 250 WORDS)

Isolation, speciation, and antibiogram of clinically relevant non-diphtherial Corynebacteria (Diphtheroids).

PubMed

Reddy, B S; Chaudhury, A; Kalawat, U; Jayaprada, R; Reddy, Gsk; Ramana, B V

2012-01-01

Coryneform or the non-diphtherial Corynebacterium species largely remains a neglected group with the traditional consideration of these organisms as contaminants. This concept, however, is slowly changing in the light of recent observations. This study has been done to find out the species distribution and antibiogram of various members of the clinically relevant Coryneform group, isolated from various clinical materials. One hundred and fourteen non-duplicate isolates of diphtheroids from various clinical isolates were selected for the study. The isolates were identified to the species level by using a battery of tests; and antimicrobial susceptibility was tested by using a combination of Clinical and Laboratory Standards Institute (CLSI) and the British Society for Antimicrobial Chemotherapy (BSAC) guidelines, in the absence of definitive CLSI guidelines. Corynebacterium amycolatum was the predominant species (35.9%) in our series followed by the CDC Group G organisms (15.7%). Each of the remaining 19 species comprised of less than 10% of the isolates. More than half the total isolates were resistant to the penicillins, erythromycin, and clindamycin; while excellent activity (all the strains being susceptible) was shown by vancomycin, linezolid, and tigecycline. Chloramphenicol and tetracycline also had good activity in inhibiting more than 80% of the isolates. Multiply drug resistance was exhibited by all the species. This study was an attempt to establish the clinical significance of coryneform organisms. The high level of resistance shown by this group to some of the common antibacterial agents highlights the importance of processing these isolates in select conditions to guide the clinicians towards an appropriate therapy.

Clonal diversity of extended-spectrum beta-lactamase producing Escherichia coli isolates in fecal samples of wild animals.

PubMed

Cristóvão, Filipe; Alonso, Carla Andrea; Igrejas, Gilberto; Sousa, Margarida; Silva, Vanessa; Pereira, José Eduardo; Lozano, Carmen; Cortés-Cortés, Gerardo; Torres, Carmen; Poeta, Patrícia

2017-03-01

The clonal diversity of extended-spectrum-β-lactamase (ESBL)-producing Escherichia coli isolates from nine different species of wild animals from distinct regions of Portugal and Spain and their content in replicon plasmids were analyzed. Among the initial 53 ESBL-producing E. coli isolates that were studied (from previous studies), 28 were selected, corresponding to different animal origins with distinct ESBL types and pulsed-field gel electrophoresis (PFGE) patterns. These 28 isolates produced different ESBLs ascribed to the following families: CTX-M, SHV and TEM. The isolates were classified into three phylogenetic groups: B1 (n = 11), A (n = 10) and D (n = 7). The seven E. coli of phylogroup D were then typed by multilocus sequence typing and ascribed to four distinct sequence types: ST117, ST115, ST2001 and ST69. The clonal diversity and relationship between isolates was studied by PFGE. Lastly, the plasmids were analyzed according to their incompatibility group using the PCR-based-replicon-typing scheme. A great diversity of replicon types was identified, with up to five per isolate. Most of the CTX-M-1 and SHV-12 producing E. coli isolates carried IncI1 or IncN replicons. The diversity of ESBL-producing E. coli isolates in wild animals, which can be disseminated in the environment, emphasizes the environmental and health problems that we face nowadays. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Exopolysaccharides produced by clinical strains belonging to the Burkholderia cepacia complex.

PubMed

Herasimenka, Yury; Cescutti, Paola; Impallomeni, Giuseppe; Campana, Silvia; Taccetti, Giovanni; Ravenni, Novella; Zanetti, Flavio; Rizzo, Roberto

2007-04-01

In the frame of a research line dedicated to better clarify the role of exopolysaccharides (EPS) in bacterial virulence, EPS produced by species of the Burkholderia cepacia complex (Bcc), namely Burkholderia multivorans, Burkholderia cenocepacia, and a Bcc member of undetermined genomovar, all isolated at the Cystic Fibrosis Regional Centre of Florence (Italy), were investigated for they structural properties. Three strains of B. multivorans, three of B. cenocepacia and one of a Bcc member of undetermined genomovar were isolated from CF patients. The reference strains C1576 and J2315, for genomovar II and III, respectively, were included in the study. The bacteria were grown on solid media, the exopolysaccharides produced were purified, and their structures were determined. In addition, sugar analysis of sputum samples was accomplished to search for EPS produced in vivo. Six strains out of seven produced the exopolysaccharide cepacian, while one strain of B. multivorans produced a completely different polymer, previously known in the literature as PS1. Two strains synthesised very small amounts of EPS. No definitive evidence for the presence of cepacian in sputum samples was found. Most strains examined produced abundant amounts of polysaccharides. Cepacian was the most common EPS isolated and its production was not associated to a particular genomovar.

[Phenotypic and molecular identification of extended-spectrum beta-lactamase (ESBL) TEM and SHV produced by clinical isolates Escherichia coli and Klebsiella spp. in hospitals].

PubMed

González Mesa, Leonora; Ramos Morí, Astrid; Nadal Becerra, Loreta; Morffi Figueroa, Janet; Hernández Robledo, Ernesto; Alvarez, Ana Berta; Marchena Bequer, Juan J; González Alemán, Mabel; Villain Plous, Carlos

2007-01-01

Nosocomial infections caused by gram-negative bacilli which produce extended spectrum beta-lactamase (ESBL) are associated with the increase of morbidity and mortality in hospitals. The objective of this study was to evaluate the frequency of ESBL, specifically the TEM and SHV type, produced by Escherichia coli and Klebsiella spp. strains, and also to determine the antimicrobial susceptibility of these isolates in comparison with other antibiotic families. A total of 326 strains were collected between 2002-2004 from hospitals in Havana City. The susceptibility tests were carried out according to the NCCLS guides and they were confirmed as. ESBL producers by the double disk diffusion method. The molecular characterization of these enzymes was determined by polymerase chain reaction (PCR), using two sets of oligonucleotides to amplify genes encoding TEM and SHV type beta-lactamase. The ESBL phenotype was detected in 31 (10%) Escherichia coli isolates, 19 of these strains (61%) carried the blaTEM genes, 5 (16%) blaSHV genes, 4 (12%) strains carried both genes and 11 strains (35%) carried the non-ESBL blaTEM and blaSHV genes. In Klebsiella spp. the ESBL phenotype was detected in 10 (36 %) isolates, only one strain carried the blaTEM gene. The most active antimicrobials against Escherichia coli were ciprofloxacin (64.5%) and gentamicin (58.07%); in the case of Klebsiella spp. the same antimicrobials were the most active with similar susceptibility (70%) for both. The carbapenems still remain the most active antibiotics against Escherichia coli and Klebsiella spp. strains, which are ESBL producers. However, their use should be closely controlled.

Frequency and expression of mutacin biosynthesis genes in isolates of Streptococcus mutans with different mutacin-producing phenotypes.

PubMed

Kamiya, Regianne Umeko; Höfling, José Francisco; Gonçalves, Reginaldo Bruno

2008-05-01

The aim of this study was to analyse the frequency and expression of biosynthesis genes in 47 Streptococcus mutans isolates with different mutacin-producing phenotypes. Detection of the frequency and expression of genes encoding mutacin types I, II, III and IV were carried out by PCR and semi-quantitative RT-PCR, respectively, using primers specific for each type of biosynthesis gene. In addition, a further eight genes encoding putative bacteriocins, designated bsm 283, bsm 299, bsm 423, bsm 1889c, bsm 1892c, bsm 1896, bsm 1906c and bsm 1914, were also screened. There was a high phenotypic diversity; some Streptococcus mutans isolates presented broad antimicrobial spectra against other Streptococcus mutans clinical isolates, including bacteria resistant to common antibiotics, as well as Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis and Streptococcus pyogenes. The expression frequency of the bsm gene was higher than that of the previously characterized mutacins (I-IV). There was no positive correlation between the number of indicator strains inhibited (antimicrobial spectra) and the number of biosynthesis genes expressed (Spearman correlation test, r=-0.03, P>0.05). In conclusion, the high diversity of mutacin-producing phenotypes, associated with high frequency of expression of the biosynthesis genes screened, reveals a broad repertoire of genetic determinants encoding antimicrobial peptides that can act in different combinations.

Molecular characterization and antibiotic susceptibility of Haemophilus influenzae clinical isolates.

PubMed

K L Ç, Hüseyin; Akyol, Selcan; Parkan, Õmür Mustafa; Dinç, Gõkçen; Sav, Hafize; Aydemir, Gonca

2017-03-01

Haemophilus influenzae can cause invasive and severe infections in both adults and children such as otitis media, sinusitis, pneumonia, meningitis and bacteremia. The emerging antibiotic resistance in recent years against ampicillin and several other antibiotics among strains of H. influenzae gives cause for serious concern. Here, we investigate ß-lactamase (BL) activity in clinical isolates of H. influenzae, profile their resistance to antibiotics, and characterize the clonal relationship of the isolates. Antibiotic susceptibilities of 92 clinical isolates of H. influenzae (March 2011-May 2012) were determined using the disk diffusion method according to the Clinical & Laboratory Standards Institute (CLSI), and BL activity was detected using the nitrocefin disk method. The Rep-PCR method was used to characterize clonality of the isolates. All strains were found to be susceptible to levofloxacin and cefotaxime. Four isolates out of 92 (4.3%) were found resistant to ampicillin, one isolate (1.1%) was resistant to amoxicillin/clavulanic acid, 21 isolates (22.8%) were resistant to trimethoprim-sulfamethoxazole (SXT), and three isolates (3.3%) showed BL activity. One strain was BL-negative but resistant to ampicillin. The three isolates with BL activity and four isolates with resistance to ampicillin did not have a clonal relationship. Three distinct clones [clone A (with subclones A1 and A2), clone B, and clone C] were identified among the SXT-resistant strains. Most of the H. influenzae isolates in this study were susceptible to the antibiotics while SXT resistance was relatively more prevalent, which suggests that significant obstacles in the therapeutic use of antibiotics against H. influenzae strains are not expected in our region.

Clinical and veterinary isolates of Salmonella enterica serovar Enteritidis defective in lipopolysaccharide O-chain polymerization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guard-Petter, J.; Parker, C.T.; Asokan, K.

1999-05-01

Twelve human and chicken isolates of Salmonella enterica serovar Enteritidis belonging to phage types 4, 8, 13a, and 23 were characterized for variability in lipopolysaccharide (LPS) composition. Isolates were differentiated into two groups, i.e., those that lacked immunoreactive O-chain, termed rough isolates, and those that had immunoreactive O-chain, termed smooth isolates. Isolates within these groups could be further differentiated by LPS compositional differences as detected by gel electrophoresis and gas liquid chromatography of samples extracted with water, which yielded significantly more LPS in comparison to phenol-chloroform extraction. The rough isolates were of two types, the O-antigen synthesis mutants and themore » O-antigen polymerization (wzy) mutants. Smooth isolates were also of two types, one producing low-molecular-weight (LMW) LPS and the other producing high-molecular-weight (HMW) LPS. To determine the genetic basis for the O-chain variability of the smooth isolates, the authors analyzed the effects of a null mutation in the O-chain length determinant gene, wzz (cld) of serovar Typhimurium. This mutation results in a loss of HMW LPS; however, the LMW LPS of this mutant was longer and more glucosylated than that from clinical isolates of serovar Enteritidis. Cluster analysis of these data and of those from two previously characterized isogenic strains of serovar Enteritidis that had different virulence attributes indicated that glucosylation of HMW LPS (via oafR function) is variable and results in two types of HMW structures, one that is highly glucosylated and one that is minimally glucosylated. These results strongly indicate that naturally occurring variability in wzy, wzz, and oafR function can be used to subtype isolates of serovar Enteritidis during epidemiological investigations.« less

Isolation of proteolytic bacteria from mealworm (Tenebrio molitor) exoskeletons to produce chitinous material.

PubMed

da Silva, Fernanda Kerche Paes; Brück, Dieter W; Brück, Wolfram M

2017-09-15

The use of insects as a source of protein is becoming an important factor for feeding an increasing population. After protein extraction for food use, the insect exoskeleton may offer the possibility for the production of added value products. Here, the aim was to isolate bacteria from the surface of farmed mealworms (Tenebrio molitor Linnaeus, 1758) for the production of chitinous material from insect exoskeletons using microbial fermentation. Isolates were screened for proteases and acid production that may aid deproteination and demineralisation of insects through fermentation to produce chitin. Selected isolates were used single-step (isolated bacteria only) or two-step fermentations with Lactobacillus plantarum (DSM 20174). Two-step fermentations with isolates from mealworm exoskeletons resulted in a demineralisation of 97.9 and 98.5% from deproteinated mealworm fractions. Attenuated total reflectance-Fourier- transform infrared spectroscopy analysis showed that crude chitin was produced. However, further optimisation is needed before the process can be upscaled. This is, to our knowledge, the first report using microbial fermentation for the extraction of chitin from insects. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Ibuprofen-Mediated Reversal of Fluconazole Resistance in Clinical Isolates of Candida

PubMed Central

Sharma, Monika; Kotwal, Aarti; Thakuria, Bhaskar; Kakati, Barnali; Chauhan, Bhupendra Singh; Patras, Abhishek

2015-01-01

Introduction: In view of the increasing prevalence of invasive Candidiasis in today’s health-care scenario and the emergence of fluconazole resistance among clinical isolates of Candida, we sought to determine if Ibuprofen could elicit a reversal of fluconazole resistance and thereby offer a potential therapeutic breakthrough in fluconazole-resistant Candidiasis. Materials and Methods: We selected 69 clinical isolates of Candida, which demonstrated an MIC of >32 μg/ml for fluconazole, and subjected them to broth microdilution in presence and absence of Ibuprofen. Results: Forty two of the 69 isolates (60.9%) demonstrated reversal of Fluconazole resistance with concomitant use of Ibuprofen. This was characterized by significant species-wise variation (p=0.00008), with all the C. albicans isolates and none of the C. glabrata isolates demonstrating such reversal. Only 22.2% and 37.7% of C. krusei and C. tropicalis isolates respectively showed Ibuprofen-mediated reversal of Fluconazole resistance. Conclusion: Since Ibuprofen is a known efflux pump inhibitor, our findings hint at the possible mechanism of Fluconazole resistance in most of our Candida isolates and suggest a potential therapeutic alternative that could be useful in the majority of Fluconazole-resistant clinical isolates of Candida. PMID:25737988

RAPD- and ERIC-Based Typing of Clinical and Environmental Pseudomonas aeruginosa Isolates.

PubMed

Auda, Ibtesam Ghadban; Al-Kadmy, Israa M S; Kareem, Sawsan Mohammed; Lafta, Aliaa Khyuon; A'Affus, Mustafa Hussein Obeid; Khit, Ibrahim Abd Aloahd; Al Kheraif, Abdulaziz Abdullah; Divakar, Darshan Devang; Ramakrishnaiah, Ravikumar

2017-03-01

Pseudomonas aeruginosa is a major cause of nosocomial infection in children and adults, resulting in significant morbidity and mortality due to its ability to acquire drug resistance. The ability of P. aeruginosa in the environment to cause infection in individuals has been reported previously; henceforth, surveillance of the emergence and transmission of P. aeruginosa strains among patients is important for infection control in a clinical setup. Various gene-typing methods have been used for epidemiological typing of P. aeruginosa isolates for the purpose of surveillance. In this work, the suitability and comparability of two typing methods, enterobacterial repetitive intergenic consensus (ERIC)-PCR and random amplification of polymorphic DNA (RAPD)-PCR fingerprinting, were studied to characterize P. aeruginosa strains isolated from clinical and environmental sources. Forty-four clinical and environmental bacterial isolates of P. aeruginosa were collected between October 2015 and January 2016. DNA extraction, ERIC-PCR and RAPD-PCR, agarose gel electrophoresis, and phylogenetic analyses were carried using the unweighted pair-group method with mean. RAPD typing revealed less clonality among clinical isolates, whereas the ERIC method showed greater similarity in comparison with RAPD. Environmental isolates, however, showed greater similarity using RAPD compared with ERIC typing. With only a few exceptions, most clinical isolates were distinct from environmental isolates, irrespective of the typing method. In conclusion, both the RAPD and ERIC typing methods proved to be good tools in understanding clonal diversity. The results also suggest that there is no relationship between clinical and environmental isolates. The absence of clonality among the clinical isolates may indicate that most P. aeruginosa infection cases could be endemic and not epidemic and that endemic infections may be due to nonclonal strains of P. aeruginosa.

Technological properties of bacteriocin-producing lactic acid bacteria isolated from Pico cheese an artisanal cow's milk cheese.

PubMed

Ribeiro, S C; Coelho, M C; Todorov, S D; Franco, B D G M; Dapkevicius, M L E; Silva, C C G

2014-03-01

Evaluate technologically relevant properties from bacteriocin-producing strains to use as starter/adjunct cultures in cheese making. Eight isolates obtained from Pico cheese produced in Azores (Portugal) were found to produce bacteriocins against Listeria monocytogenes and three isolates against Clostridium perfringens. They were identified as Lactococcus lactis and Enterococcus faecalis and submitted to technological tests: growth at different conditions of temperature and salt, acid production, proteolysis, lipolysis, coexistence, enzymatic profile and autolytic capacity. Safety evaluation was performed by evaluating haemolytic, gelatinase and DNase activity, resistance to antibiotics and the presence of virulence genes. Some isolates presented good technological features such as high autolytic activity, acid and diacetyl production. Lactococcus lactis was negative for all virulence genes tested and inhibit the growth of all Lactic acid bacteria (LAB) isolates. Enterococci were positive for the presence of some virulence genes, but none of the isolates were classified as resistant to important antibiotics. The bacteriocin-producing Lc. lactis present good potential for application in food as adjunct culture in cheese production. The study also reveals good technological features for some Enterococcus isolates. Bacteriocin-producing strains presented important technological properties to be exploited as new adjunct culture for the dairy industry, influencing flavour development and improve safety. © 2013 The Society for Applied Microbiology.

Antifungal susceptibility of 175 Aspergillus isolates from various clinical and environmental sources.

PubMed

Sabino, Raquel; Carolino, Elisabete; Veríssimo, Cristina; Martinez, Marife; Clemons, Karl V; Stevens, David A

2016-10-01

Some environmental Aspergillus spp. isolates have been described as resistant to antifungals, potentially causing an emerging medical problem. In the present work, the antifungal susceptibility profile of 41 clinical and 134 environmental isolates of Aspergillus was determined using the CLSI microdilution method. The aim of this study was to compare environmental and clinical isolates with respect to their susceptibility, and assess the potential implications for therapy of isolates encountered in different environments. To our knowledge, this is the first report comparing antifungal susceptibility profiles of Aspergillus collected from different environmental sources (poultries, swineries, beach sand, and hospital environment). Significant differences were found in the distribution of the different species sections for the different sources. Significant differences were also found in the susceptibility profile of the different Aspergillus sections recovered from the various sources. Clear differences were found between the susceptibility of clinical and environmental isolates for caspofungin, amphotericin B and posaconazole, with clinical isolates showing overall greater susceptibility, except for caspofungin. In comparison to clinical isolates, hospital environmental isolates showed significantly less susceptibility to amphotericin B and posaconazole. These data indicate that species section identity and the site from which the isolate was recovered influence the antifungal susceptibility profile, which may affect initial antifungal choices. © The Author 2016. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Antimicrobial resistance and beta-lactamase production of clinical isolates of prevotella and porphyromonas species.

PubMed

Bahar, Hrisi; Torun, Muzeyyen Mamal; Demirci, Mehmet; Kocazeybek, Bekir

2005-03-01

This study determined the beta-lactamase production and the antimicrobial resistance of 72 Prevotella species and 48 Porphyromonas species isolated from different clinical specimens. All strains were identified using API 32 ID. The beta-lactamase production was determined by nitrocefin disks. E test strips of benzylpenicillin, ampicillin + sulbactam, cefoxitin, clindamycin, metronidazole and imipenem were tested for each strain. Nineteen Prevotella melaninogenica, 18 Prevotella intermedia, 16 Prevotella denticola, 11 Prevotella loescheii and 8 Prevotella bivia strains were identified. Four were clindamycin resistant. The highest beta-lactamase production was found at a rate of 68.4% in P. melaninogenica species. Additionally, 33 Porphyromonas asaccharolytica and 15 Porphyromonas gingivalis strains were identified. None of them produced beta-lactamase. In view of the emerging antibiotic resistance among anaerobes, the current local susceptibility profile of our Prevotella and Porphyromonas species will establish the basis for additional surveys tracing significant changes in the antimicrobial resistance of our clinical isolates. Copyright 2005 S. Karger AG, Basel.

First report of extended-spectrum β-lactamases among clinical isolates of Escherichia coli in Gaza Strip, Palestine.

PubMed

Tayh, Ghassan; Ben Sallem, Rym; Ben Yahia, Houssem; Gharsa, Haythem; Klibi, Naouel; Boudabous, Abdellatif; Ben Slama, Karim

2016-09-01

This study aimed to assess the occurrence of extended-spectrum β-lactamases (ESBLs) in clinical Escherichia coli isolates from Palestine and to characterise their type, genetic environments and associated resistance genes. Twenty-seven broad-spectrum-cephalosporin-resistant E. coli isolates were recovered between April and June 2013 in Gaza Strip hospitals. Characterisation of ESBL genes and their genetic environments, detection of associated resistance genes, and the presence and characterisation of integrons were performed by PCR and sequencing. The clonal relationship among ESBL-positive E. coli strains was determined by pulsed-field gel electrophoresis (PFGE) using the restriction enzyme XbaI. Phylogroup typing and virulence factors were studied by PCR. The following ESBL genes were identified: blaCTX-M-15 (21 isolates); blaCTX-M-14a (2 isolates); blaCTX-M-1 (2 isolates); blaCTX-M-3 (1 isolate); and blaCTX-M-27 (1 isolate). The blaTEM-1 gene was also detected in eight CTX-M-producing strains. The ISEcp1 sequence was found upstream of blaCTX-M in 23 isolates, and orf477 was found downstream of this gene in 24 isolates. IS903 was also detected downstream in three isolates. Six isolates carried class 1 integrons with the gene cassette arrangement dfrA17-aadA5. High clonal diversity was observed among the studied isolates by PFGE (24 unrelated profiles). The virulence gene fimA was detected in 23 isolates, the aer gene in 8 isolates and the papC gene in 7 isolates. The studied isolates belonged to phylogroups B2 (12 isolates), D (12 isolates) and A (3 isolates). This is the first report of the detection of CTX-M class β-lactamases in E. coli of clinical origin in Gaza Strip hospitals. Copyright © 2016 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.

Gymnemagenin-producing endophytic fungus isolated from a medicinal plant Gymnema sylvestre R.Br.

PubMed

Parthasarathy, Ramalingam; Sathiyabama, Muthukrishnan

2014-03-01

Gymnema sylvestre is a plant containing the triterpenoid gymnemagenin, which is used in the pharmaceutical industry as an antidiabetic agent. The objective of this study was to determine whether endophytic fungi, isolated from G. sylvestre, produce gymnemagenin. We isolated an endophytic fungal strain from the leaves of G. sylvestre which produces gymnemagenin in the medium. The fungus was identified as Penicillium oxalicum based on morphological and molecular methods. The strain had a component with the same TLC Rf value and HPLC retention time as authentic gymnemagenin. The presence of gymnemagenin was further confirmed by FTIR, UV, and (1)H NMR analyses.

METHOD FOR MICRORNA ISOLATION FROM CLINICAL SERUM SAMPLES

PubMed Central

Li, Yu; Kowdley, Kris V.

2012-01-01

MicroRNAs are a group of intracellular non-coding RNA molecules that have been implicated in a variety of human diseases. Due to their high stability in blood, microRNAs released into circulation could be potentially utilized as non-invasive biomarkers for diagnosis or prognosis. Current microRNA isolation protocols are specifically designed for solid tissues and are impractical for biomarker development utilizing small-volume serum samples on a large scale. Thus, a protocol for microRNA isolation from serum is needed to accommodate these conditions in biomarker development. To establish such a protocol, we developed a simplified approach to normalize sample input by using single synthetic spike-in microRNA. We evaluated three commonly used commercial microRNA isolation kits for the best performance by comparing RNA quality and yield. The manufacturer’s protocol was further modified to improve the microRNA yield from 200 μL of human serum. MicroRNAs isolated from a large set of clinical serum samples were tested on the miRCURY LNA real-time PCR panel and confirmed to be suitable for high-throughput microRNA profiling. In conclusion, we have established a proven method for microRNA isolation from clinical serum samples suitable for microRNA biomarker development. PMID:22982505

Detection of Different β-Lactamases and their Co-existence by Using Various Discs Combination Methods in Clinical Isolates of Enterobacteriaceae and Pseudomonas spp.

PubMed Central

Rawat, Vinita; Singhai, Monil; Verma, Pankaj Kumar

2013-01-01

Background: Resistance to broad spectrum beta-lactams mediated by extended spectrum β-lactamase (ESBL), AmpC, and metallobetalactamase (MBLs) enzymes are an increasing problem worldwide. The study was aimed to detect occurrence rate and to evaluate different substrates and inhibitors by disc combination method for detecting varying degree of β-lactamase enzymes and their co-production. Materials and Methods: A disc panel containing imipenem (IMP), IMP/EDTA, ceftazidime (CA), ceftazidime-tazobactum (CAT), CAT/cloxacillin (CLOX), ceftazidime-clavulanic acid (CAC), CAC/CLOX, cefoxitin (CN), and CN/CLOX in a single plate was used to detect presence of ESBLs, AmpC, and MBLs and/or their co-existence in 184 consecutive, nonrepetitive, clinical isolates of Enterobacteriace (n = 96) and Pseudomonas spp. (n = 88) from pus samples of hospitalized patients, resistant to 3rd generation cephalosporins. Results: Out of a total of 96 clinical isolates of Enterobacteriaceae, 18.7, 20.8, and 27% were pure ESBL, AmpC, and MBL producers, respectively. ESBL and AmpC were co-produced by 25% isolates. Among 88 Pseudomonas spp. 38.6, 13, and 6% were pure MBL, ESBL, and AmpC producers, respectively. ESBL/AmpC and MBL/AmpC co-production was seen in 20% and 18% isolates, respectively. Among ESBL and AmpC co-producers, CA/CAC/CLOX disc combination (DC) missed 7 of the 24 ESBL producers in Enterobacteriace and 4 of the 18 ESBL in Pseudomonas spp., which were detected by CA/CAT/CLOX DC. No mechanism was detected among 8.3% Enterobacteriaceae and 2.3% Pseudomonas isolates. Conclusion: Diagnostic problems posed by co-existence of different classes of β-lactamases in a single isolate could be solved by disc combination method by using simple panel of discs containing CA, CAT, CAT/CLOX, IMP, and IMP/EDTA. PMID:24014963

Characterization of some bacteriocins produced by lactic acid bacteria isolated from fermented foods.

PubMed

Grosu-Tudor, Silvia-Simona; Stancu, Mihaela-Marilena; Pelinescu, Diana; Zamfir, Medana

2014-09-01

Lactic acid bacteria (LAB) isolated from different sources (dairy products, fruits, fresh and fermented vegetables, fermented cereals) were screened for antimicrobial activity against other bacteria, including potential pathogens and food spoiling bacteria. Six strains have been shown to produce bacteriocins: Lactococcus lactis 19.3, Lactobacillus plantarum 26.1, Enterococcus durans 41.2, isolated from dairy products and Lactobacillus amylolyticus P40 and P50, and Lactobacillus oris P49, isolated from bors. Among the six bacteriocins, there were both heat stable, low molecular mass polypeptides, with a broad inhibitory spectrum, probably belonging to class II bacteriocins, and heat labile, high molecular mass proteins, with a very narrow inhibitory spectrum, most probably belonging to class III bacteriocins. A synergistic effect of some bacteriocins mixtures was observed. We can conclude that fermented foods are still important sources of new functional LAB. Among the six characterized bacteriocins, there might be some novel compounds with interesting features. Moreover, the bacteriocin-producing strains isolated in our study may find applications as protective cultures.

Characterization of N-Acylhomoserine Lactones Produced by Bacteria Isolated from Industrial Cooling Water Systems.

PubMed

Okutsu, Noriya; Morohoshi, Tomohiro; Xie, Xiaonan; Kato, Norihiro; Ikeda, Tsukasa

2015-12-30

The cooling water systems are used to remove heat generated in the various industries. Biofouling of the cooling water systems causes blocking of condenser pipes and the heat exchanger tubes. In many Gram-negative bacteria, N-acylhomoserine lactone (AHL) are used as quorum-sensing signal molecule and associated with biofilm formation. To investigate the relationship between quorum sensing and biofouling in the cooling water system, we isolated a total of 192 bacterial strains from the five cooling water systems, and screened for AHL production. Seven isolates stimulated AHL-mediated purple pigment production in AHL reporter strain Chromobacterium violaceum CV026 or VIR07. Based on their 16S rRNA gene sequences, AHL-producing isolates were assigned to Aeromonas hydrophila, Lysobacter sp., Methylobacterium oryzae, and Bosea massiliensis. To the best of our knowledge, B. massiliensis and Lysobacter sp. have not been reported as AHL-producing species in the previous researches. AHLs extracted from the culture supernatants of B. massiliensis and Lysobacter sp. were identified by liquid chromatography-mass spectrometry. AHLs produced by B. massiliensis were assigned as N-hexanoyl-L-homoserine lactone (C6-HSL), N-(3-oxohexanoyl)-L-homoserine lactone (3-oxo-C6-HSL), and N-(3-oxooctanoyl)-L-homoserine lactone (3-oxo-C8-HSL). AHLs produced by Lysobacter sp. were assigned as N-decanoyl-L-homoserine lactone (C10-HSL) and N-(3-oxodecanoyl)-L-homoserine lactone (3-oxo-C10-HSL). This is the first report of identification of AHLs produced by B. massiliensis and Lysobacter sp. isolated from the cooling water system.

Isolation of pandemic Vibrio parahaemolyticus from UK water and shellfish produce.

PubMed

Powell, Andy; Baker-Austin, Craig; Wagley, Sariqa; Bayley, Amanda; Hartnell, Rachel

2013-05-01

Vibrio parahaemolyticus is a Gram-negative, halophilic bacterium found commonly in temperate and warm estuarine waters worldwide. V. parahaemolyticus is considered an emerging bacterial pathogen in Europe and has been responsible for several recent seafood-associated outbreaks. During ad hoc testing of raw shellfish produce in May 2012, pandemic group (O3:K6) V. parahaemolyticus was isolated from Pacific oysters (Crassostrea gigas), harvested in Southern England. Follow-on testing of water and shellfish, encompassing a small number geographically diverse sites, also retrieved pandemic group isolates. These strains are amongst the most northerly pandemic strains described to date and represent the first instance of pandemic V. parahaemolyticus isolated in the UK, highlighting the expanding geographical distribution of these foodborne pathogens in the environment.

Limits of patient isolation measures to control extended-spectrum beta-lactamase–producing Enterobacteriaceae: model-based analysis of clinical data in a pediatric ward

PubMed Central

2013-01-01

Background Extended-spectrum beta-lactamase–producing Enterobacteriaceae (ESBL-E) are a growing concern in hospitals and the community. How to control the nosocomial ESBL-E transmission is a matter of debate. Contact isolation of patients has been recommended but evidence supporting it in non-outbreak settings has been inconclusive. Methods We used stochastic transmission models to analyze retrospective observational data from a two-phase intervention in a pediatric ward, successively implementing single-room isolation and patient cohorting in an isolation ward, combined with active ESBL-E screening. Results For both periods, model estimates suggested reduced transmission from isolated/cohorted patients. However, most of the incidence originated from sporadic sources (i.e. independent of cross-transmission), unaffected by the isolation measures. When sporadic sources are high, our model predicted that even substantial efforts to prevent transmission from carriers would have limited impact on ESBL-E rates. Conclusions Our results provide evidence that, considering the importance of sporadic acquisition, e.g. endogenous selection of resistant strains following antibiotic treatment, contact-isolation measures alone might not suffice to control ESBL-E. They also support the view that estimating cross-transmission extent is key to predicting the relative success of contact-isolation measures. Mathematical models could prove useful for those estimations and guide decisions concerning the most effective control strategy. PMID:23618041

Genotyping of Mycobacterium intracellulare isolates and clinical characteristics of lung disease.

PubMed

Kim, S-Y; Lee, S-T; Jeong, B-H; Park, H Y; Jeon, K; Kim, J-W; Shin, S J; Koh, W-J

2013-05-01

Variable number of tandem repeats (VNTR) loci were recently identified in Japanese isolates of Mycobacterium intracellulare. We hypothesised that some mycobacterial genotypes are more virulent than others, resulting in particular genotypes being associated with disease phenotype and progression. To evaluate the VNTR loci of M. intracellulare in clinical isolates from Korean patients, and investigate the association between mycobacterial genotype and disease phenotype and progression. In total, 70 M. intracellulare clinical isolates were genotyped using 16 M. intracellulare VNTR loci. VNTR typing showed strong discriminatory power and genetic diversity for molecular epidemiological studies of M. intracellulare. In a phylogenetic tree, the M. intracellulare clinical isolates were divided into two clusters (A and B). Cluster A was observed more frequently (77%) than Cluster B; however, there was no association between the clinical characteristics, disease progression, drug susceptibility and clusters based on VNTR genotyping. VNTR typing could be used for epidemiological studies of M. intracellulare lung disease; however, no association was found between the specific VNTR genotypes of M. intracellulare and the clinical characteristics of Korean patients.

Artemisinin-resistant Plasmodium falciparum clinical isolates can infect diverse mosquito vectors of Southeast Asia and Africa.

PubMed

St Laurent, Brandyce; Miller, Becky; Burton, Timothy A; Amaratunga, Chanaki; Men, Sary; Sovannaroth, Siv; Fay, Michael P; Miotto, Olivo; Gwadz, Robert W; Anderson, Jennifer M; Fairhurst, Rick M

2015-10-20

Artemisinin-resistant Plasmodium falciparum parasites are rapidly spreading in Southeast Asia, yet nothing is known about their transmission. This knowledge gap and the possibility that these parasites will spread to Africa endanger global efforts to eliminate malaria. Here we produce gametocytes from parasite clinical isolates that displayed artemisinin resistance in patients and in vitro, and use them to infect native and non-native mosquito vectors. We show that contemporary artemisinin-resistant isolates from Cambodia develop and produce sporozoites in two Southeast Asian vectors, Anopheles dirus and Anopheles minimus, and the major African vector, Anopheles coluzzii (formerly Anopheles gambiae M). The ability of artemisinin-resistant parasites to infect such highly diverse Anopheles species, combined with their higher gametocyte prevalence in patients, may explain the rapid expansion of these parasites in Cambodia and neighbouring countries, and further compromise efforts to prevent their global spread.

Carbapenem-resistant Citrobacter spp. isolated in Spain from 2013 to 2015 produced a variety of carbapenemases including VIM-1, OXA-48, KPC-2, NDM-1 and VIM-2.

PubMed

Arana, David M; Ortega, Adriana; González-Barberá, Eva; Lara, Noelia; Bautista, Verónica; Gómez-Ruíz, Dolores; Sáez, David; Fernández-Romero, Sara; Aracil, Belén; Pérez-Vázquez, María; Campos, José; Oteo, Jesús

2017-12-01

There is little information about carbapenemase-producing (CP) Citrobacter spp. We studied the molecular epidemiology and microbiological features of CP Citrobacter spp. isolates collected in Spain (2013-15). In total, 119 isolates suspected of being CP by the EUCAST screening cut-off values were analysed. Carbapenemases and ESBLs were characterized using PCR and sequencing. The genetic relationship among Citrobacter freundii isolates was studied by PFGE. Of the 119 isolates, 63 (52.9%) produced carbapenemases, of which 37 (58.7%) produced VIM-1, 20 (31.7%) produced OXA-48, 12 (19%) produced KPC-2, 2 (3.2%) produced NDM-1 and 1 (1.6%) produced VIM-2; 9 C. freundii isolates co-produced VIM-1 plus OXA-48. Fourteen isolates (22.2%) also carried ESBLs: 8 CTX-M-9 plus SHV-12, 2 CTX-M-9, 2 SHV-12 and 2 CTX-M-15. Fifty-seven isolates (90.5%) were C. freundii, 4 (6.3%) were Citrobacter koseri, 1 (1.6%) was Citrobacter amalonaticus and 1 (1.6%) was Citrobacter braakii. By EUCAST breakpoints, eight (12.7%) of the CP isolates were susceptible to the four carbapenems tested. In the 53 CP C. freundii analysed by PFGE, a total of 44 different band patterns were observed. Four PFGE clusters were identified: cluster 1 included eight isolates co-producing VIM-1 and OXA-48; blaVIM-1 was carried in a class 1 integron (intI-blaVIM-1-aacA4-dfrB1-aadA1-catB2-qacEΔ1/sul1) and blaOXA-48 was carried in a Tn1999.2 transposon. We observed the clonal and polyclonal spread of CP Citrobacter spp. across several Spanish geographical areas. Four species of Citrobacter spp. produced up to five carbapenemase types, including co-production of VIM-1 plus OXA-48. Some CP Citrobacter spp. isolates were susceptible to the four carbapenems tested, a finding with potential clinical implications. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Antibiotic resistance and virulence traits in clinical and environmental Enterococcus faecalis and Enterococcus faecium isolates.

PubMed

Rathnayake, I U; Hargreaves, M; Huygens, F

2012-07-01

This study compared virulence and antibiotic resistance traits in clinical and environmental Enterococcus faecalis and Enterococcus faecium isolates. E. faecalis isolates harboured a broader spectrum of virulence determinants compared to E. faecium isolates. The virulence traits Cyl-A, Cyl-B, Cyl-M, gel-E, esp and acm were tested and environmental isolates predominantly harboured gel-E (80% of E. faecalis and 31.9% of E. faecium) whereas esp was more prevalent in clinical isolates (67.8% of E. faecalis and 70.4% of E. faecium). E. faecalis and E. faecium isolated from water had different antibiotic resistance patterns compared to those isolated from clinical samples. Linezolid resistance was not observed in any isolates tested and vancomycin resistance was observed only in clinical isolates. Resistance to other antibiotics (tetracycline, gentamicin, ciprofloxacin and ampicillin) was detected in both clinical and water isolates. Clinical isolates were more resistant to all the antibiotics tested compared to water isolates. Multi-drug resistance was more prevalent in clinical isolates (71.2% of E. faecalis and 70.3% of E. faecium) compared to water isolates (only 5.7% E. faecium). tet L and tet M genes were predominantly identified in tetracycline-resistant isolates. All water and clinical isolates resistant to ciprofloxacin and ampicillin contained mutations in the gyrA, parC and pbp5 genes. A significant correlation was found between the presence of virulence determinants and antibiotic resistance in all the isolates tested in this study (p<0.05). The presence of antibiotic resistant enterococci, together with associated virulence traits, in surface recreational water could be a public health risk. Copyright © 2012 Elsevier GmbH. All rights reserved.

Current state of purification, isolation and analysis of bacteriocins produced by lactic acid bacteria.

PubMed

Kaškonienė, Vilma; Stankevičius, Mantas; Bimbiraitė-Survilienė, Kristina; Naujokaitytė, Gintarė; Šernienė, Loreta; Mulkytė, Kristina; Malakauskas, Mindaugas; Maruška, Audrius

2017-02-01

The scientific interest for the search of natural means of microbial inhibitors has not faded for several years. A search of natural antibiotics, so-called bacteriocins which are produced by lactic acid bacteria (LAB), gains a huge attention of the scientists in the last century, in order to reduce the usage of synthetic food additives. Pure bacteriocins with wide spectra of antibacterial activity are promising among the natural biopreservatives. The usage of bacteriocin(s) producing LAB as starter culture for the fermentation of some food products, in order to increase their shelf-life, when synthetic preservatives are not allowable, is also possible. There are a lot of studies focusing on the isolation of new bacteriocins from traditional fermented food, dairy products and other foods or sometimes even from unusual non-food matrices. Bacteriocins producing bacteria have been isolated from different sources with the different antibacterial activity against food-borne microorganisms. This review covers the classification of bacteriocins, diversity of sources of bacteriocin(s) producing LAB, antibacterial spectra of isolated bacteriocins and analytical methods for the bacteriocin purification and analysis within the last 15 years.

Selection and Characterization of Biofuel-Producing Environmental Bacteria Isolated from Vegetable Oil-Rich Wastes

PubMed Central

Escobar-Niño, Almudena; Luna, Carlos; Luna, Diego; Marcos, Ana T.; Cánovas, David; Mellado, Encarnación

2014-01-01

Fossil fuels are consumed so rapidly that it is expected that the planet resources will be soon exhausted. Therefore, it is imperative to develop alternative and inexpensive new technologies to produce sustainable fuels, for example biodiesel. In addition to hydrolytic and esterification reactions, lipases are capable of performing transesterification reactions useful for the production of biodiesel. However selection of the lipases capable of performing transesterification reactions is not easy and consequently very few biodiesel producing lipases are currently available. In this work we first isolated 1,016 lipolytic microorganisms by a qualitative plate assay. In a second step, lipolytic bacteria were analyzed using a colorimetric assay to detect the transesterification activity. Thirty of the initial lipolytic strains were selected for further characterization. Phylogenetic analysis revealed that 23 of the bacterial isolates were Gram negative and 7 were Gram positive, belonging to different clades. Biofuel production was analyzed and quantified by gas chromatography and revealed that 5 of the isolates produced biofuel with yields higher than 80% at benchtop scale. Chemical and viscosity analysis of the produced biofuel revealed that it differed from biodiesel. This bacterial-derived biofuel does not require any further downstream processing and it can be used directly in engines. The freeze-dried bacterial culture supernatants could be used at least five times for biofuel production without diminishing their activity. Therefore, these 5 isolates represent excellent candidates for testing biofuel production at industrial scale. PMID:25099150

Recombinant Scorpine Produced Using SUMO Fusion Partner in Escherichia coli Has the Activities against Clinically Isolated Bacteria and Inhibits the Plasmodium falciparum Parasitemia In Vitro

PubMed Central

Gu, Yaping; Zhou, Huayun; Cao, Jun; Gao, Qi

2014-01-01

Scorpine, a small cationic peptide from the venom of Pandinus imperator, which has been shown to have anti-bacterial and anti-plasmodial activities, has potential important applications in the pharmaceutical industries. However, the isolation of scorpine from natural sources is inefficient and time-consuming. Here, we first report the expression and purification of recombinant scorpine in Escherichia coli, using small ubiquitin-related modifier (SUMO) fusion partner. The fusion protein was expressed in soluble form in E. coli, and expression was verified by SDS-PAGE and western blotting analysis. The fusion protein was purified to 90% purity by nickel–nitrilotriacetic acid (Ni2+–NTA) resin chromatography. After the SUMO-scorpine fusion protein was cleaved by the SUMO protease, the cleaved sample was reapplied to a Ni2+–NTA column. Tricine/SDS-PAGE gel results indicated that Scorpine had been purified successfully to more than 95% purity. The recombinantly expressed Scorpine showed anti-bacterial activity against two standard bacteria including Staphylococcus aureus ATCC 29213 and Acinetobacter baumannii ATCC 19606, and clinically isolated bacteria including S. aureus S, S. aureus R, A. baumannii S, and A. baumannii R. It also produced 100% reduction in Plasmodium falciparum parasitemia in vitro. Thus, the expression strategy presented in this study allowed convenient high yield and easy purification of recombinant Scorpine for pharmaceutical applications in the future. PMID:25068263

Bacillus subtilis UBTn7, a potential producer of L - Methioninase isolated from mangrove, Rhizophora mucronata

NASA Astrophysics Data System (ADS)

Prihanto, A. A.

2018-04-01

L-methioninase is an enzyme that degrades sulfur-containing amino acids to α-keto acids, ammonia, and thiols. L-methioninase could be found in plants, bacteria, and fungi. The aims of this study was to obtain L-methioninase-producing endophytic bacteria isolated from mangrove Rhizophora mucronata. The mangrove was collected from Jenu Beach, Tuban, East Java, Indonesia. The samples were roots, stems, and leaves of Rhizophora mucronata. Endophytic bacteria were pure isolated using LB agar medium. Each bacteria were screened its capability to produce L-methioninase using selective media namely modified Czapek Dox agar. The best producer of enzyme was further identified with morphological and biochemical analysis. The result showed that three bacteria produced L-methioninase. Based on the result of morphological and biochemical analysis, the best producer was Bacillus subtilis UBTn7.

Epidemiology and clinical features of community-onset bacteremia caused by extended-spectrum β-lactamase-producing Klebsiella pneumoniae.

PubMed

Lee, Jeong-a; Kang, Cheol-In; Joo, Eun-Jeong; Ha, Young Eun; Kang, Seung-Ji; Park, So Yeon; Chung, Doo Ryeon; Peck, Kyong Ran; Ko, Kwan Soo; Lee, Nam Yong; Song, Jae-Hoon

2011-06-01

There is limited clinical information regarding community-onset bacteremia caused by extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae. This study was performed to evaluate risk factors and clinical outcomes of community-onset bacteremia caused by ESBL-producing K. pneumoniae. A total of 435 patients with community-onset K. pneumoniae bacteremia were included and data from patients with ESBL-producing K. pneumoniae bacteremia were compared to those with non-ESBL-producing bacteremia. Isolates with ESBLs were microbiologically characterized. Of 435 patients with community-onset K. pneumoniae bacteremia, 33 (7.6%) were infected with ESBL producers, of which 25 were further classified as healthcare-associated infections. The most common underlying diseases were solid tumors (n = 20, 60.6%) and diabetes mellitus (n = 10, 30.3%), and the most common infection was intra-abdominal infection (n = 20, 60.6%). Multivariate analysis showed that corticosteroid use (odds ratio [OR] = 13.73, 95% confidence interval [CI] = 1.93-97.6, p = 0.009), percutaneous tubes (OR = 7.30, 95% CI = 2.41-22.12, p < 0.001), and prior receipt of antibiotics (OR = 5.65, 95% CI = 2.43-14.16, p < 0.001) were significant factors associated with ESBL producers. When the 30-day mortality rate was evaluated, no significant difference was found between ESBL group and non-ESBL group (12.1% [4/32] vs. 16.0% [35/192]; p = 0.429). Among 16 isolates, for which the ESBL characterization was performed by PCR, the most common types of ESBLs were SHV (n = 16) and cefotaxime-M-2 (n = 5). Pulsed-field gel electrophoresis analysis of the ESBL-producing organisms showed extensive clonal diversity. ESBL-producing K. pneumoniae is a significant cause of bacteremia, even in patients with community-onset infections, particularly in patients with corticosteroid use, percutaneous tube, prior receipt of antibiotics, or healthcare

Risk factors and impacts of clinical and subclinical mastitis in commercial meat-producing sheep flocks in Quebec, Canada.

PubMed

Arsenault, Julie; Dubreuil, Pascal; Higgins, Robert; Bélanger, Denise

2008-11-17

We conducted a prospective observational study on clinical and subclinical mastitis in 30 commercial meat-producing sheep flocks from 2 regions of the province of Quebec, Canada. A total of 2,792 ewes selected in late gestation were followed from lambing to weaning of lambs. The incidence of clinical mastitis for the total lactation period (average of 58 days) ranged among flocks from 0 to 6.6%, with a median of 1.2%. The most frequently isolated bacteria from the cases of clinical mastitis, in pure or mixed culture, were Mannheimia haemolytica (26%), Staphylococcus aureus (23%), and coagulase-negative staphylococci (17%). Incidence of clinical mastitis was higher in ewes that gave birth to 3 or more lambs and from the Estrie region, and was associated with an increase in ewe mortality, an increase in lamb mortality at the litter level, and a decrease in lamb's weaning weight for lambs born in multiple litter size or from ewes >or=4 years old. Among 354 selected ewes with clinically normal udder at the end of lactation, 28.8% had potentially pathogenic bacteria isolated from milk. The most prevalent bacteria were S. aureus (9.3%) and coagulase-negative staphylococci (9.3%). The risk of having a positive culture in at least one half was different between the two regions. Prevalence of ewes (n=261) with California Mastitis Test (CMT) positive result in at least one half was 24.1 and 14.9% using a cut-off of >or=1+ and >or=2+, respectively. Prevalence of culture-positive udder halves was 11.7% for CMT-negative compared with 53.6% for CMT 3+ halves. CMT status was positively associated with the isolation of coagulase-negative staphylococci, M. haemolytica, S. aureus, and various Streptococcus species, but not with other isolated bacteria. Additionally, prevalence of CMT-positive halves was higher in ewes from the Estrie region, aged of >or=4 years versus 1 year, having clinical mastitis previously detected in the lactation and/or with low body condition score. Lamb

Molecular Characterization of Extended-Spectrum-β-Lactamase-Producing and Plasmid-Mediated AmpC β-Lactamase-Producing Escherichia coli Isolated from Stray Dogs in South Korea

PubMed Central

Tamang, Migma Dorji; Nam, Hyang-Mi; Jang, Geum-Chan; Kim, Su-Ran; Chae, Myung Hwa; Jung, Suk-Chan; Byun, Jae-Won; Park, Yong Ho

2012-01-01

A total of 47 extended-spectrum-cephalosporin-resistant Escherichia coli strains isolated from stray dogs in 2006 and 2007 in the Republic of Korea were investigated using molecular methods. Extended-spectrum β-lactamase (ESBL) and AmpC β-lactamase phenotypes were identified in 12 and 23 E. coli isolates, respectively. All 12 ESBL-producing isolates carried blaCTX-M genes. The most common CTX-M types were CTX-M-14 (n = 5) and CTX-M-24 (n = 3). Isolates producing CTX-M-3, CTX-M-55, CTX-M-27, and CTX-M-65 were also identified. Twenty-one of 23 AmpC β-lactamase-producing isolates were found to carry blaCMY-2 genes. TEM-1 was associated with CTX-M and CMY-2 β-lactamases in 4 and 15 isolates, respectively. In addition to blaTEM-1, two isolates carried blaDHA-1, and one of them cocarried blaCMY-2. Both CTX-M and CMY-2 genes were located on large (40 to 170 kb) conjugative plasmids that contained the insertion sequence ISEcp1 upstream of the bla genes. Only in the case of CTX-M genes was there an IS903 sequence downstream of the gene. The spread of ESBLs and AmpC β-lactamases occurred via both horizontal gene transfer, accounting for much of the CTX-M gene dissemination, and clonal spread, accounting for CMY-2 gene dissemination. The horizontal dissemination of blaCTX-M and blaCMY-2 genes was mediated by IncF and IncI1-Iγ plasmids, respectively. The clonal spread of blaCMY-2 was driven mainly by E. coli strains of virulent phylogroup D lineage ST648. To our knowledge, this is the first report of blaDHA-1 in E. coli strains isolated from companion animals. This study also represents the first report of CMY-2 β-lactamase-producing E. coli isolates from dogs in the Republic of Korea. PMID:22354297

Characteristic of Enterococcus faecium clinical isolates with quinupristin/dalfopristin resistance in China.

PubMed

Wang, Shanshan; Guo, Yinjuan; Lv, Jingnan; Qi, Xiuqin; Li, Dan; Chen, Zengqiang; Zhang, Xueqing; Wang, Liangxing; Yu, Fangyou

2016-10-21

Quinupristin/dalfopristin (Q/D) is a valuable alternative antibiotic to vancomycin for the treatment of multi-drug resistant Enterococcus faecium infections. However, resistance to Q/D in E. faecium clinical isolates and nosocomial dissemination of Q/D-resistant E. faecium have been reported in several countries and should be of concern. From January 2012 to December 2015, 911 E. faecium clinical isolates were isolated from various specimens of inpatients at the first Affiliated Hospital of Wenzhou Medical University located in Wenzhou, east China. Of 911 E. faecium clinical isolates, 9 (1.0 %, 9/911) were resistant to Q/D, with the Q/D MIC values of 64 mg/L(1), 32 mg/L(1), 16 mg/L(3), 8 mg/L(1) and 4 mg/L(3) determined by broth microdilution. All Q/D-resistant isolates were susceptible to vancomycin, tigecycline and teicoplanin but resistant to penicillin, ampicillin and erythromycin. vatE was only found in one Q/D-resistant E. faecium isolate while vatD was not detected in any of the isolates tested. 8 of 9 Q/D-resistant E. faecium isolates were found be positive for both ermB and msrC. The combinations of Q/D resistance determinants were ermB-msrC (7 isolates) and ermB-msrC-vatE (one isolate). ST78, ST761, ST94, ST21 and ST323 accounted for 4, 2, 1, 1 and 1 isolate, respectively, among which ST78 was the prevalent ST. Q/D-resistant E. faecium clinical isolates were first described in China. Carriage of vatE, ermB and msrC was responsible for Q/D resistance.

Artemisinin-resistant Plasmodium falciparum clinical isolates can infect diverse mosquito vectors of Southeast Asia and Africa

PubMed Central

St. Laurent, Brandyce; Miller, Becky; Burton, Timothy A.; Amaratunga, Chanaki; Men, Sary; Sovannaroth, Siv; Fay, Michael P.; Miotto, Olivo; Gwadz, Robert W.; Anderson, Jennifer M.; Fairhurst, Rick M.

2015-01-01

Artemisinin-resistant Plasmodium falciparum parasites are rapidly spreading in Southeast Asia, yet nothing is known about their transmission. This knowledge gap and the possibility that these parasites will spread to Africa endanger global efforts to eliminate malaria. Here we produce gametocytes from parasite clinical isolates that displayed artemisinin resistance in patients and in vitro, and use them to infect native and non-native mosquito vectors. We show that contemporary artemisinin-resistant isolates from Cambodia develop and produce sporozoites in two Southeast Asian vectors, Anopheles dirus and Anopheles minimus, and the major African vector, Anopheles coluzzii (formerly Anopheles gambiae M). The ability of artemisinin-resistant parasites to infect such highly diverse Anopheles species, combined with their higher gametocyte prevalence in patients, may explain the rapid expansion of these parasites in Cambodia and neighbouring countries, and further compromise efforts to prevent their global spread. PMID:26485448

Simultaneous gut colonisation and infection by ESBL-producing Escherichia coli in hospitalised patients.

PubMed

Asir, Johny; Nair, Shashikala; Devi, Sheela; Prashanth, Kenchappa; Saranathan, Rajagopalan; Kanungo, Reba

2015-01-01

Extended spectrum betalactamase (ESBL)-producing organisms are a major cause of hospital-acquired infections. ESBL-producing Escherichia coli (E. coli) have been recovered from the hospital environment. These drug-resistant organisms have also been found to be present in humans as commensals. The present investigation intended to isolate ESBL-producing E. coli from the gut of already infected patients; to date, only a few studies have shown evidence of the gut microflora as a major source of infection. This study aimed to detect the presence of ESBL genes in E.coli that are isolated from the gut of patients who have already been infected with the same organism. A total of 70 non-repetitive faecal samples were collected from in-patients of our hospital. These in-patients were clinically diagnosed and were culture-positive for ESBL-producing E. coli either from blood, urine, or pus. Standard microbiological methods were used to detect ESBL from clinical and gut isolates. Genes coding for major betalactamase enzymes such as bla CTX-M , bla TEM, and bla SHV were investigated by polymerase chain reaction (PCR). ESBL-producing E. coli was isolated from 15 (21 per cent) faecal samples of the 70 samples that were cultured. PCR revealed that out of these 15 isolates, the bla CTX-M gene was found in 13 (86.6 per cent) isolates, the bla TEM was present in 11 (73.3 per cent) isolates, and bla SHV only in eight (53.3 per cent) isolates. All 15 clinical and gut isolates had similar phenotypic characters and eight of the 15 patients had similar pattern of genes (bla TEM, bla CTX-M, and bla SHV) in their clinical and gut isolates. Strains with multiple betalactamase genes that colonise the gut of hospitalised patients are a potential threat and it may be a potential source of infection.

Isolation and Characterization of Thermophilic Bacteria from Jordanian Hot Springs: Bacillus licheniformis and Thermomonas hydrothermalis Isolates as Potential Producers of Thermostable Enzymes.

PubMed

Mohammad, Balsam T; Al Daghistani, Hala I; Jaouani, Atef; Abdel-Latif, Saleh; Kennes, Christian

2017-01-01

The aim of this study was the isolation and characterization of thermophilic bacteria from hot springs in Jordan. Ten isolates were characterized by morphological, microscopic, biochemical, molecular, and physiological characteristics. Sequencing of the 16S rDNA of the isolates followed by BLAST search revealed that nine strains could be identified as Bacillus licheniformis and one isolate as Thermomonas hydrothermalis . This is the first report on the isolation of Thermomonas species from Jordanian hot springs. The isolates showed an ability to produce some thermostable enzymes such as amylase, protease, cellulose, gelatins, and lecithin. Moreover, the UPGMA dendrogram of the enzymatic characteristics of the ten isolates was constructed; results indicated a high phenotypic diversity, which encourages future studies to explore further industrial and environmental applications.

In Vitro Antifungal Susceptibility of Neoscytalidium dimidiatum Clinical Isolates from Malaysia.

PubMed

James, Jasper Elvin; Santhanam, Jacinta; Lee, Mei Chen; Wong, Choon Xian; Sabaratnam, Parameswari; Yusoff, Hamidah; Tzar, Mohd Nizam; Razak, Mohd Fuat Abdul

2017-04-01

Neoscytalidium dimidiatum is an opportunistic fungus causing cutaneous infections mostly, which are difficult to treat due to antifungal resistance. In Malaysia, N. dimidiatum is associated with skin and nail infections, especially in the elderly. These infections may be mistaken for dermatophyte infections due to similar clinical appearance. In this study, Neoscytalidium isolates from cutaneous specimens, identified using morphological and molecular methods (28 Neoscytalidium dimidiatum and 1 Neoscytalidium sp.), were evaluated for susceptibility towards antifungal agents using the CLSI broth microdilution (M38-A2) and Etest methods. Amphotericin B, voriconazole, miconazole and clotrimazole showed high in vitro activity against all isolates with MIC ranging from 0.0313 to 1 µg/mL. Susceptibility towards fluconazole and itraconazole was noted in up to 10% of isolates, while ketoconazole was inactive against all isolates. Clinical breakpoints for antifungal drugs are not yet available for most filamentous fungi, including Neoscytalidium species. However, the results indicate that clinical isolates of N. dimidiatum in Malaysia were sensitive towards miconazole, clotrimazole, voriconazole and amphotericin B, in vitro.

Antimicrobial resistance pattern of Neisseria gonorrhoeae isolates from peripheral health centres and STD clinic attendees of a tertiary care centre in India.

PubMed

Bala, M; Ray, K; Gupta, S M

2008-06-01

The aim of the study was to compare the antimicrobial resistance pattern of Neisseria gonorrhoeae isolates from urban and rural peripheral health centres and from sexually transmitted disease (STD) clinic attendees. Antimicrobial susceptibility testing of 191 N. gonorrhoeae isolates (165 isolates from STD clinic attendees and 26 from peripheral health centres) was carried out in Delhi, India, using the calibrated dichotomous sensitivity technique for penicillin, tetracycline, ceftriaxone, ciprofloxacin, spectinomycin and nalidixic acid, and minimum inhibitory concentrations were determined using E-test. Penicillin-resistant, ciprofloxacin-resistant, penicillinase-producing N. gonorrhoeae and tetracycline-resistant N. gonorrhoeae strains were higher in STD clinic attendees than in peripheral health centres, probably because of less antibiotic pressure in the peripheral areas. High-level resistance to ciprofloxacin and multiresistant strains were also higher in STD clinic attendees. The present study emphasizes the importance of surveillance of antimicrobial resistance of N. gonorrhoeae in different population subgroups in order to monitor the spread of multiresistant strains and to update the national treatment recommendations.

RESPONSES OF OYSTER (CRASSOSTREA VIRGINICA) HEMOCYTES TO NONPATHOGENIC AND CLINICAL ISOLATES OF VIBRIO PARAHAEMOLYTICUS

EPA Science Inventory

Bacterial uptake by oysters (Crassostrea virginica) and bactericidal activity of oyster hemocytes were studied using four environmental isolates and three clinical isolates of Vibrio parahaemolyticus. Clinical isolates (2030, 2062, 2107) were obtained from gastroenteritis patien...

Glutaminase-producing Meyerozyma (Pichia) guilliermondii isolated from Thai soy sauce fermentation.

PubMed

Aryuman, Phichayaphorn; Lertsiri, Sittiwat; Visessanguan, Wonnop; Niamsiri, Nuttawee; Bhumiratana, Amaret; Assavanig, Apinya

2015-01-02

In this study, 34 yeast isolates were obtained from koji and moromi samples of Thai soy sauce fermentation. However, the most interesting yeast strain was isolated from the enriched 2 month-old (M2) moromi sample and identified as Meyerozyma (Pichia) guilliermondii EM2Y61. This strain is a salt-tolerant yeast that could tolerate up to 20% (w/v) NaCl and produce extracellular and cell-bound glutaminases. Interestingly, its glutaminases were more active in 18% (w/v) NaCl which is a salt concentration in moromi. The extracellular glutaminase's activity was found to be much higher than that of cell-bound glutaminase. The highest specific activity and stability of the extracellular glutaminase were found in 18% (w/v) NaCl at pH4.5 and 37°C. A challenge test by adding partially-purified extracellular glutaminase from M. guilliermondii EM2Y61 into 1 month-old (M1) moromi sample showed an increased conversion of L-glutamine to L-glutamic acid. This is the first report of glutaminase producing M. guilliermondii isolated from the moromi of Thai soy sauce fermentation. The results suggested the potential application of M. guilliermondii EM2Y61 as starter yeast culture to increase l-glutamic acid during soy sauce fermentation. Copyright © 2014 Elsevier B.V. All rights reserved.

Prevalence of extended-spectrum beta-lactamase-producing Enterobacteriaceae isolated from blood cultures in Africa.

PubMed

Sangare, S A; Maiga, A I; Guindo, I; Maiga, A; Camara, N; Savadogo, S; Diallo, S; Bougoudogo, F; Armand-Lefevre, L; Andremont, A; Maiga, I I

2015-09-01

Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae have been isolated from many regions of the world. Epidemiological studies are being conducted in Europe, North America, and Asia. No study has however been conducted in Africa to determine the prevalence and distribution of ESBLs on the continent. This literature review aimed at describing the prevalence of ESBL-producing Enterobacteriaceae isolated from blood cultures, as well as the ESBL genes involved at the international level. Our focus was mainly on Africa. We conducted a literature review on PubMed. Articles related to our study field and published between 1996 and 2014 were reviewed and entirely read for most of them, while we only focused on the abstracts of some other articles. Relevant articles to our study were then carefully reviewed and included in the review. The prevalence of ESBL-producing Enterobacteriaceae differs from one country to another. The results of our literature review however indicate that class A ESBLs prevail over the other types. We took into consideration articles focusing on various types of samples to assess the prevalence of ESBL-producing Enterobacteriaceae, but information on isolates from blood cultures is limited. The worldwide prevalence of ESBL-producing Enterobacteriaceae has increased over time. Evidence of ESBL-producing Enterobacteriaceae can be found in all regions of the world. Studies conducted in Africa mainly focused on the Northern and Eastern parts of the continent, while only rare studies were carried out in the rest of the continent. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Acid-producing capacity from sugars and sugar alcohols among Lactobacillus isolates collected in connection with radiation therapy.

PubMed

Almståhl, Annica; Rudbäck, Helena; Basic, Amina; Carlén, Anette; Alstad, Torgny

2017-12-01

To investigate the acid-producing capacity from sugars and sugar alcohols of oral Lactobacillus collected in connection with radiation therapy (RT) to the head and neck region. Lactobacillus were collected from the tongue, buccal mucosa and supragingival plaque in 24 patients before, during, and after RT. The acid-producing capacity of Lactobacillus isolates (n=211) was analyzed using a colorimetric fermentation test in microtiter plates. Solutions containing 2% sugars (sucrose, glucose, fructose, lactose) or sugar-alcohols (sorbitol and xylitol) were used. After 24h of incubation, bacterial acid-producing capacity was determined as strong (pH<5), weak (pH  ≥5-≤ 6) or low/absent (pH>6). Data regarding intake frequency of sugar-rich products and products with sugar-alcohols was collected. The highest acid-producing capacity using the sugars was seen for isolates collected during RT. Sorbitol was fermented to a higher extent during and post RT, especially among isolates from plaque. Lactobacillus fermenting xylitol showed the highest acid-producing capacity during RT (p<0.05). No statistically significant correlations between stimulated whole salivary secretion rate and acid-producing capacity, or between the intake frequency of sugar-rich products or sugar-alcohol containing products and Lactobacillus acid-producing capacity, were found. The results suggest that Lactobacillus isolates, collected from the tongue, buccal mucosa and supragingival plaque, have a higher acid-producing capacity using sugars and sugar-alcohols during RT than one year post RT. Copyright © 2017 Elsevier Ltd. All rights reserved.

Therapeutic clinical applications of reactor-produced radioisotopes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knapp, F.F. Jr.

1997-12-01

One of the most rapidly growing areas of clinical nuclear medicine is the therapeutic use of radioisotopes for applications in oncology, rheumatology and, more recently, interventional cardiology. With the rapidly increasing development and evaluation of new agents, their introduction into clinical use, and commercialization, the availability of high levels of therapeutic reactor-produced neutron-rich radioisotopes is of increasing importance. The goals of this paper are to discuss the issues associated with optimization of the production and processing of reactor-produced radioisotopes for therapy, with special emphasis on {sup 188}W, and the optimization of the use of the {sup 188}W/{sup 188}Re generator. Inmore » addition, other key examples of therapeutic radioisotopes of current interest and their specific clinical applications are discussed.« less

Prevalence of ESBL-producing Enterobacteriaceae isolated from blood cultures in Mali.

PubMed

Sangare, Samba Adama; Maiga, Almoustapha Issiaka; Guindo, Ibrehima; Maiga, Aminata; Camara, Namory; Dicko, Oumar Agaly; Diallo, Souleymane; Bougoudogo, Flabou; Armand-Lefevre, Laurence; Andremont, Antoine; Maiga, Ibrahim Izetiegouma

2016-10-31

The increasing frequency of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae is becoming a serious public health concern. This study sought to determine ESBL frequency in Enterobacteriaceae isolated from patients' blood cultures in two university teaching hospitals of Bamako, Mali. During a three-month period, the presence of Enterobacteriaceae from blood cultures of patients admitted to the university teaching hospitals of Bamako was evaluated. The microbial identifications were initially performed with an API 20E gallery and VITEK2 locally in Mali, and then confirmation in France was performed with a mass spectrometry MALDI-TOF in the bacteriology laboratory of the university teaching hospital of Bichat. Antibiotic susceptibility profiles were determined by the diffusion method as recommended by the European Committee on Antimicrobial Susceptibility Testing (EUCAST). The isolated species were K. pneumoniae (14/40; 35.0%), E. coli (11/40; 27.5%), and E. cloacae (9/40; 22.5%). Of the strains isolated, 21/34 (61.8%) had an ESBL phenotype, including 10/14 (71.4%) K. pneumoniae, 8/11 (72.7%) E. coli, and 3/9 (33.3%) E. cloacae. Resistances associated with ESBL strains of K. pneumoniae, E. coli, and E. cloacae were as follows: gentamicin (10/10, 100%; 6/8, 75%; 2/3, 67%, respectively), amikacin (2/10, 20%; 0/8, 0%; 0/3, 0%, respectively), ofloxacin (8/10, 80%; 7/8, 87%; 3/3, 100%, respectively), and cotrimoxazole (10/10, 100%; 6/8, 75%; 3/3, 100%, respectively). Almost two-thirds (61.8%) of Enterobacteriaceae isolated from our blood cultures were ESBL producers. Only susceptibilities to carbapenems and to amikacin were fully conserved within the strains.

Pseudomonas aeruginosa-producing Metallo-β-lactamases (VIM, IMP, SME, and AIM) in the Clinical Isolates of Intensive Care Units, a University Hospital in Isfahan, Iran.

PubMed

Khorvash, Farzin; Yazdani, Mohammadreza; Shabani, Shiva; Soudi, Aliasghar

2017-01-01

Pseudomonas aeruginosa is a severe challenge for antimicrobial therapy, due to the chromosomal mutations or exhibition of intrinsic resistance to various antimicrobial agents such as most β-lactams. We undertook this study to evaluate the existence of SME, IMP, AIM, and VIM metallo-β-lactamases (MBL) encoding genes among P. aeruginosa strains isolated from Intensive Care Unit (ICU) patients in Al-Zahra Hospital in Isfahan, Iran. In a retrospective cross-sectional study that was conducted between March 2012 and April 2013, a total of 48 strains of P. aeruginosa were collected from clinical specimens of bedridden patients in ICU wards. Susceptibility test was performed by disc diffusion method. All of the meropenem-resistant strains were subjected to modified Hodge test for detection of carbapenemases. Multiplex polymerase chain reaction was performed for detection of blaVIM, blaIMP, blaAIM, and blaSME genes. In disk diffusion method, imipenem and meropenem showed the most and colistin the least resistant antimicrobial agents against P. aeruginosa strains. Of the 48 isolates, 36 (75%) were multidrug resistant (MDR). Amplification of β-lactamase genes showed the presence of blaVIM genes in 7 (%14.6) strains and blaIMP genes in 15 (31.3%) strains. All of the isolates were negative for blaSME and blaAIM genes. We could not find any statistically significant difference among the presence of this gene and MDR positive, age, or source of the specimen. As patients with infections caused by MBL-producing bacteria are at an intensified risk of treatment failure, fast determination of these organisms is necessary. Our findings may provide useful insights in replace of the appropriate antibiotics and may also prevent MBLs mediated resistance problem.

Pseudomonas aeruginosa-producing Metallo-β-lactamases (VIM, IMP, SME, and AIM) in the Clinical Isolates of Intensive Care Units, a University Hospital in Isfahan, Iran

PubMed Central

Khorvash, Farzin; Yazdani, Mohammadreza; Shabani, Shiva; Soudi, Aliasghar

2017-01-01

Background: Pseudomonas aeruginosa is a severe challenge for antimicrobial therapy, due to the chromosomal mutations or exhibition of intrinsic resistance to various antimicrobial agents such as most β-lactams. We undertook this study to evaluate the existence of SME, IMP, AIM, and VIM metallo-β-lactamases (MBL) encoding genes among P. aeruginosa strains isolated from Intensive Care Unit (ICU) patients in Al-Zahra Hospital in Isfahan, Iran. Materials and Methods: In a retrospective cross-sectional study that was conducted between March 2012 and April 2013, a total of 48 strains of P. aeruginosa were collected from clinical specimens of bedridden patients in ICU wards. Susceptibility test was performed by disc diffusion method. All of the meropenem-resistant strains were subjected to modified Hodge test for detection of carbapenemases. Multiplex polymerase chain reaction was performed for detection of blaVIM, blaIMP, blaAIM, and blaSME genes. Results: In disk diffusion method, imipenem and meropenem showed the most and colistin the least resistant antimicrobial agents against P. aeruginosa strains. Of the 48 isolates, 36 (75%) were multidrug resistant (MDR). Amplification of β-lactamase genes showed the presence of blaVIM genes in 7 (%14.6) strains and blaIMP genes in 15 (31.3%) strains. All of the isolates were negative for blaSME and blaAIM genes. We could not find any statistically significant difference among the presence of this gene and MDR positive, age, or source of the specimen. Conclusion: As patients with infections caused by MBL-producing bacteria are at an intensified risk of treatment failure, fast determination of these organisms is necessary. Our findings may provide useful insights in replace of the appropriate antibiotics and may also prevent MBLs mediated resistance problem. PMID:29285477

Characterization and identification of enzyme-producing microflora isolated from the gut of sea cucumber Apostichopus japonicus

NASA Astrophysics Data System (ADS)

Li, Fenghui; Gao, Fei; Tan, Jie; Fan, Chaojing; Sun, Huiling; Yan, Jingping; Chen, Siqing; Wang, Xiaojun

2016-01-01

Gut microorganisms play an important role in the digestion of their host animals. The purpose of this research was to isolate and assess the enzyme-producing microbes from the Apostichopus japonicus gut. Thirty-nine strains that can produce at least one of the three digestive enzymes (protease, amylase, and cellulase) were qualitatively screened based on their extracellular enzyme-producing abilities. The enzyme-producing strains clustered into eight groups at the genetic similarity level of 100% by analyzing the restriction patterns of 16S rDNA amplified with Mbo I. Phylogenetic analysis revealed that 37 strains belonged to the genus Bacillus and two were members of the genus Virgibacillus. Enzyme-producing capability results indicate that the main enzyme-producing microflora in the A. japonicus gut was Bacillus, which can produce protease, amylase, and cellulase. Virgibacillus, however, can only produce protease. The high enzyme-producing capability of the isolates suggests that the gut microbiota play an important role in the sea cucumber digestive process.

Alternaria sp. MG1, a resveratrol-producing fungus: isolation, identification, and optimal cultivation conditions for resveratrol production.

PubMed

Shi, Junling; Zeng, Qin; Liu, Yanlin; Pan, Zhongli

2012-07-01

Due to its potential in preventing or slowing the occurrence of many diseases, resveratrol (3,5,4'-trihydroxystilbene) has attracted great research interest. The objective of this study was to identify microorganisms from selected plants that produce resveratrol and to optimize the conditions for resveratrol production. Endophytes from Merlot wine grapes (Vitis vinifera L. cv. Merlot), wild Vitis (Vitis quinquangularis Rehd.), and Japanese knotweed (Polygonum cuspidatum Siebold & Zucc.) were isolated, and their abilities to produce resveratrol were evaluated. A total of 65 isolates were obtained and 21 produced resveratrol (6-123 μg/L) in liquid culture. The resveratrol-producing isolates belonged to seven genera, Botryosphaeria, Penicillium, Cephalosporium, Aspergillus, Geotrichum, Mucor, and Alternaria. The resveratrol-producing capability decreased or was completely lost in most isolates after three rounds of subculture. It was found that only the strain Alternaria sp. MG1 (isolated from cob of Merlot using GA1 medium) had stable and high resveratrol-producing capability in all subcultures. During liquid cultivation of Alternaria sp. MG1 in potato dextrose medium, the synthesis of resveratrol began on the first day, increased to peak levels on day 7, and then decreased sharply thereafter. Cell growth increased during cultivation and reached a stable and high level of biomass after 5 days. The best fermentation conditions for resveratrol production in liquid cultures of Alternaria sp. MG1 were an inoculum size of 6 %, a medium volume of 125 mL in a 250-mL flask, a rotation speed of 101 rpm, and a temperature of 27 °C.

In vitro activity of AT-4140 against clinical bacterial isolates.

PubMed

Kojima, T; Inoue, M; Mitsuhashi, S

1989-11-01

The activity of AT-4140, a new fluoroquinolone, was evaluated against a wide range of clinical bacterial isolates and compared with those of existing analogs. AT-4140 had a broad spectrum and a potent activity against gram-positive and -negative bacteria, including Legionella spp. and Bacteroides fragilis. The activity of AT-4140 against gram-positive and -negative cocci, including Acinetobacter calcoaceticus, was higher than those of ciprofloxacin, ofloxacin, and norfloxacin. Its activity against gram-negative rods was generally comparable to that of ciprofloxacin. Some isolates of methicillin-resistant Staphylococcus aureus (MIC of methicillin, greater than or equal to 12.5 micrograms/ml) were resistant to existing quinolones, but many of them were still susceptible to AT-4140 at concentrations below 0.39 micrograms/ml. The MICs of AT-4140, ciprofloxacin, ofloxacin, and norfloxacin for 90% of clinical isolates of methicillin-resistant S. aureus were 0.2, 12.5, 6.25, and 100 micrograms/ml, respectively. AT-4140 was bactericidal for each of 20 clinical isolates of Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Serratia marcescens, and Pseudomonas aeruginosa at concentrations near the MICs. AT-4140 inhibited the supercoiling activity of DNA gyrase from E. coli.

Shared Mycobacterium avium Genotypes Observed among Unlinked Clinical and Environmental Isolates

PubMed Central

Weigel, Kris M.; Yakrus, Mitchell A.; Becker, Annie L.; Chen, Hui-Ling; Fridley, Gina; Sikora, Arthur; Speake, Cate; Hilborn, Elizabeth D.; Pfaller, Stacy

2013-01-01

Our understanding of the sources of Mycobacterium avium infection is partially based on genotypic matching of pathogen isolates from cases and environmental sources. These approaches assume that genotypic identity is rare in isolates from unlinked cases or sources. To test this assumption, a high-resolution PCR-based genotyping approach, large-sequence polymorphism (LSP)-mycobacterial interspersed repetitive unit–variable-number tandem repeat (MIRU-VNTR), was selected and used to analyze clinical and environmental isolates of M. avium from geographically diverse sources. Among 127 clinical isolates from seven locations in North America, South America, and Europe, 42 genotypes were observed. Among 12 of these genotypes, matches were seen in isolates from apparently unlinked patients in two or more geographic locations. Six of the 12 were also observed in environmental isolates. A subset of these isolates was further analyzed by alternative strain genotyping methods, pulsed-field gel electrophoresis and MIRU-VNTR, which confirmed the existence of geographically dispersed strain genotypes. These results suggest that caution should be exercised in interpreting high-resolution genotypic matches as evidence for an acquisition event. PMID:23851084

RESPONSES OF OYSTERS AND THEIR HEMOCYTES TO CLINICAL AND ENVIRONMENTAL ISOLATES OF VIBRIO PARAHAEMOLYTICUS

EPA Science Inventory

Interactions of Vibrio parahaemolyticus with oysters and oyster hemocytes were studied using three environmental isolates (1094, 1163 and ATCC 17802) and three clinical isolates (2030, 2062, 2107). Clinical isolates were from patients who became ill during the June 1998 food pois...

Characterization of five fungal endophytes producing Cajaninstilbene acid isolated from pigeon pea [Cajanus cajan (L.) Millsp].

PubMed

Gao, Yuan; Zhao, Jin Tong; Zu, Yuan Gang; Fu, Yu Jie; Wang, Wei; Luo, Meng; Efferth, Thomas

2011-01-01

Five fungal endophytes (K4, K5, K6, K9, K14) producing Cajaninstilbene acid (CSA, 3-hydroxy-4-prenyl-5-methoxystilbene-2-carboxylic acid) were isolated from the roots of pigeon pea [Cajanus cajan (L.) Millsp.]. CSA is responsible for the prominent pharmacological activities in pigeon pea. The amount of CSA in culture solution varied among the five fungal endophytes. K4 produced the highest levels of CSA (1037.13 µg/L) among the endophytes tested after incubation for five days. Both morphological characteristics and molecular methods were used for species identification of fungal endophytes. The five endophytic isolates were characterized by analyzing the internal transcribed spacer (ITS) rRNA and β-tubulin genes. The K4, K5, K9 and K14 strains isolated from pigeon pea roots were found to be closely related to the species Fusarium oxysporum. K6 was identified as Neonectria macrodidym. The present study is the first report on the isolation and identification of fungal endophytes producing CSA in pigeon pea. The study also provides a scientific base for large scale production of CSA.

Isolation and Characterization of Rhamnolipid-Producing Bacterial Strains from a Biodiesel Facility

USDA-ARS?s Scientific Manuscript database

Novel strains of rhamnolipid-producing bacteria were isolated from soils at a biodiesel facility on the basis of their ability to grow on glycerol as a sole carbon source. Strains were identified as Acinetobacter calcoaceticus, Enterobacter asburiae, E. hormaecheii, Pantoea stewartii and Pseudomona...

Geographical and meteorological factors associated with isolation of Listeria species in New York State produce production and natural environments.

PubMed

Chapin, Travis K; Nightingale, Kendra K; Worobo, Randy W; Wiedmann, Martin; Strawn, Laura K

2014-11-01

Listeria species have been isolated from diverse environments, often at considerable prevalence, and are known to persist in food processing facilities. The presence of Listeria spp. has been suggested to be a marker for Listeria monocytogenes contamination. Therefore, a study was conducted to (i) determine the prevalence and diversity of Listeria spp. in produce production and natural environments and (ii) identify geographical and/or meteorological factors that affect the isolation of Listeria spp. in these environments. These data were also used to evaluate Listeria spp. as index organisms for L. monocytogenes in produce production environments. Environmental samples collected from produce production (n = 588) and natural (n = 734) environments in New York State were microbiologically analyzed to detect and isolate Listeria spp. The prevalence of Listeria spp. was approximately 33 and 34% for samples obtained from natural environments and produce production, respectively. Co-isolation of L. monocytogenes and at least one other species of Listeria in a given sample was recorded for 3 and 9% of samples from natural environments and produce production, respectively. Soil moisture and proximity to water and pastures were highly associated with isolation of Listeria spp. in produce production environments, while elevation, study site, and proximity to pastures were highly associated with isolation of Listeria spp. in natural environments, as determined by randomForest models. These data show that Listeria spp. were prevalent in both agricultural and nonagricultural environments and that geographical and meteorological factors associated with isolation of Listeria spp. were considerably different between the two environments.

ISOLATED FROM CLINICAL AND ENVIRONMENTAL SOURCES IN NORTHEAST THAILAND.

PubMed

Mala, Wanida; Kaewkes, Wanlop; Tattawasart, Unchalee; Wongwajana, Suwin; Faksri, Kiatichai; Chomvarin, Chariya

2016-09-01

Emergence of multiple drug resistance in Vibrio cholerae has been increasing around the world including Northeast Thailand. In this study, 92 isolates of V. cholerae (50 O1 and 42 non-O1/non-O139 isolates) from clinical and environmental sources in Northeast Thailand were randomly selected and investigated for the presence of SXT element, class 1 integron and antimicrobial resistance genes. Genotypic-phenotypic concordance of antimicrobial resistance was also determined. Using PCR-based assays, 79% of V. cholerae isolates were positive for SXT element, whereas only 1% was positive for class 1 integron. SXT element harbored antimicrobial resistance genes, dfrA1 or dfr18, floR, strB, sul2, and tetA. Overall phenotypic-genotypic concordance of antimicrobial resistance was 78%, with highest and lowest value being for trimethoprim (83%) and chloramphenicol (70%), respectively. Ninety-two percent of V. cholerae O1 strains isolated from clinical sources harbored both dfrA1 (O1-specific trimethoprim resistance gene) and dfr18 (non-O1-specific trimethoprim resistance gene), whereas only 5% of V. cholerae non-O1/non-O139 strains harbored both genes. All V. cholerae O1 isolated from environmental source harbored dfr18 but 48% of V. cholerae non-O1/non-O139 harbored dfrA1. This study indicates that SXT element was the main contributor to the circulation of multiple-drug resistance determinants in V. cholerae strains in Northeast Thailand and that genetic exchange of SXT element can occur in both V. cholerae O1 and non-O1/non-O139 strains from clinical and environmental sources.

Role of AcrR and RamA in Fluoroquinolone Resistance in Clinical Klebsiella pneumoniae Isolates from Singapore

PubMed Central

Schneiders, T.; Amyes, S. G. B.; Levy, S. B.

2003-01-01

The MICs of ciprofloxacin for 33 clinical isolates of K. pneumoniae resistant to extended-spectrum cephalosporins from three hospitals in Singapore ranged from 0.25 to >128 μg/ml. Nineteen of the isolates were fluoroquinolone resistant according to the NCCLS guidelines. Strains for which the ciprofloxacin MIC was ≥0.5 μg/ml harbored a mutation in DNA gyrase A (Ser83→Tyr, Leu, or IIe), and some had a secondary Asp87→Asn mutation. Isolates for which the MIC was 16 μg/ml possessed an additional alteration in ParC (Ser80→IIe, Trp, or Arg). Tolerance of the organic solvent cyclohexane was observed in 10 of the 19 fluoroquinolone-resistant strains; 3 of these were also pentane tolerant. Five of the 10 organic solvent-tolerant isolates overexpressed AcrA and also showed deletions within the acrR gene. Complementation of the mutated acrR gene with the wild-type gene decreased AcrA levels and produced a two- to fourfold reduction in the fluoroquinolone MICs. None of the organic solvent-tolerant clinical isolates overexpressed another efflux-related gene, acrE. While marA and soxS were not overexpressed, another marA homologue, ramA, was overexpressed in 3 of 10 organic solvent-tolerant isolates. These findings indicate that multiple target and nontarget gene changes contribute to fluoroquinolone resistance in K. pneumoniae. Besides AcrR mutations, ramA overexpression (but not marA or soxS overexpression) was related to increased AcrAB efflux pump expression in this collection of isolates. PMID:12936981

[Magnetic Resonance Imaging Conversion Predictors of Clinically Isolated Syndrome to Multiple Sclerosis].

PubMed

Peixoto, Sara; Abreu, Pedro

2016-11-01

Clinically isolated syndrome may be the first manifestation of multiple sclerosis, a chronic demyelinating disease of the central nervous system, and it is defined by a single clinical episode suggestive of demyelination. However, patients with this syndrome, even with long term follow up, may not develop new symptoms or demyelinating lesions that fulfils multiple sclerosis diagnostic criteria. We reviewed, in clinically isolated syndrome, what are the best magnetic resonance imaging findings that may predict its conversion to multiple sclerosis. A search was made in the PubMed database for papers published between January 2010 and June 2015 using the following terms: 'clinically isolated syndrome', 'cis', 'multiple sclerosis', 'magnetic resonance imaging', 'magnetic resonance' and 'mri'. In this review, the following conventional magnetic resonance imaging abnormalities found in literature were included: lesion load, lesion location, Barkhof's criteria and brain atrophy related features. The non conventional magnetic resonance imaging techniques studied were double inversion recovery, magnetization transfer imaging, spectroscopy and diffusion tensor imaging. The number and location of demyelinating lesions have a clear role in predicting clinically isolated syndrome conversion to multiple sclerosis. On the other hand, more data are needed to confirm the ability to predict this disease development of non conventional techniques and remaining neuroimaging abnormalities. In forthcoming years, in addition to the established predictive value of the above mentioned neuroimaging abnormalities, different clinically isolated syndrome neuroradiological findings may be considered in multiple sclerosis diagnostic criteria and/or change its treatment recommendations.

Efficacy of Colistin and Its Combination With Rifampin in Vitro and in Experimental Models of Infection Caused by Carbapenemase-Producing Clinical Isolates of Klebsiella pneumoniae.

PubMed

Pachón-Ibáñez, María E; Labrador-Herrera, Gema; Cebrero-Cangueiro, Tania; Díaz, Caridad; Smani, Younes; Del Palacio, José P; Rodríguez-Baño, Jesús; Pascual, Alvaro; Pachón, Jerónimo; Conejo, M Carmen

2018-01-01

Despite the relevance of carbapenemase-producing Klebsiella pneumoniae (CP-Kp) infections there are a scarce number of studies to evaluate in vivo the efficacy of combinations therapies. The bactericidal activity of colistin, rifampin, and its combination was studied (time-kill curves) against four clonally unrelated clinical isolates of CP-Kp, producing VIM-1, VIM-1 plus DHA-1(acquired AmpC β-lactamase), OXA-48 plus CTX-M-15 (extended spectrum β-lactamase) and KPC-3, respectively, with colistin MICs of 0.5, 64, 0.5, and 32 mg/L, respectively. The efficacies of antimicrobials in monotherapy and in combination were tested in a murine peritoneal sepsis model, against all the CP-Kp. Their efficacies were tested in the pneumonia model against the OXA-48 plus CTX-M-15 producers. The development of colistin-resistance was analyzed for the colistin-susceptible strains in vitro and in vivo . In vitro , colistin plus rifampin was synergistic against all the strains at 24 h. In vivo , compared to the controls, rifampin alone reduced tissue bacterial concentrations against VIM-1 and OXA-48 plus CTX-M-15 strains; CMS plus rifampin reduced tissue bacterial concentrations of these two CP-Kp and of the KPC-3 strain. Rifampin and the combination increased the survival against the KPC-3 strain; in the pneumonia model, the combination also improved the survival. No resistant mutants appeared with the combination. In conclusion, CMS plus rifampin had a low and heterogeneous efficacy in the treatment of severe peritoneal sepsis model due to CP-Kp producing different carbapenemases, increasing survival only against the KPC-3 strain. The combination showed efficacy in the less severe pneumonia model. The combination prevented in vitro and in vivo the development of colistin resistant mutants.

Efficacy of Colistin and Its Combination With Rifampin in Vitro and in Experimental Models of Infection Caused by Carbapenemase-Producing Clinical Isolates of Klebsiella pneumoniae

PubMed Central

Pachón-Ibáñez, María E.; Labrador-Herrera, Gema; Cebrero-Cangueiro, Tania; Díaz, Caridad; Smani, Younes; del Palacio, José P.; Rodríguez-Baño, Jesús; Pascual, Alvaro; Pachón, Jerónimo; Conejo, M. Carmen

2018-01-01

Despite the relevance of carbapenemase-producing Klebsiella pneumoniae (CP-Kp) infections there are a scarce number of studies to evaluate in vivo the efficacy of combinations therapies. The bactericidal activity of colistin, rifampin, and its combination was studied (time–kill curves) against four clonally unrelated clinical isolates of CP-Kp, producing VIM-1, VIM-1 plus DHA-1(acquired AmpC β-lactamase), OXA-48 plus CTX-M-15 (extended spectrum β-lactamase) and KPC-3, respectively, with colistin MICs of 0.5, 64, 0.5, and 32 mg/L, respectively. The efficacies of antimicrobials in monotherapy and in combination were tested in a murine peritoneal sepsis model, against all the CP-Kp. Their efficacies were tested in the pneumonia model against the OXA-48 plus CTX-M-15 producers. The development of colistin-resistance was analyzed for the colistin-susceptible strains in vitro and in vivo. In vitro, colistin plus rifampin was synergistic against all the strains at 24 h. In vivo, compared to the controls, rifampin alone reduced tissue bacterial concentrations against VIM-1 and OXA-48 plus CTX-M-15 strains; CMS plus rifampin reduced tissue bacterial concentrations of these two CP-Kp and of the KPC-3 strain. Rifampin and the combination increased the survival against the KPC-3 strain; in the pneumonia model, the combination also improved the survival. No resistant mutants appeared with the combination. In conclusion, CMS plus rifampin had a low and heterogeneous efficacy in the treatment of severe peritoneal sepsis model due to CP-Kp producing different carbapenemases, increasing survival only against the KPC-3 strain. The combination showed efficacy in the less severe pneumonia model. The combination prevented in vitro and in vivo the development of colistin resistant mutants.

Increased PK11195-PET binding in normal-appearing white matter in clinically isolated syndrome

PubMed Central

Politis, Marios; Su, Paul; Turkheimer, Federico E.; Malik, Omar; Keihaninejad, Shiva; Wu, Kit; Waldman, Adam; Reynolds, Richard; Nicholas, Richard; Piccini, Paola

2015-01-01

The most accurate predictor of the subsequent development of multiple sclerosis in clinically isolated syndrome is the presence of lesions at magnetic resonance imaging. We used in vivo positron emission tomography with 11C-(R)-PK11195, a biomarker of activated microglia, to investigate the normal-appearing white matter and grey matter of subjects with clinically isolated syndrome to explore its role in the development of multiple sclerosis. Eighteen clinically isolated syndrome and eight healthy control subjects were recruited. Baseline assessment included: history, neurological examination, expanded disability status scale, magnetic resonance imaging and PK11195-positron emission tomography scans. All assessments except the PK11195-positron emission tomography scan were repeated over 2 years. SUPERPK methodology was used to measure the binding potential relative to the non-specific volume, BPND. We show a global increase of normal-appearing white matter PK11195 BPND in clinically isolated syndrome subjects compared with healthy controls (P = 0.014). Clinically isolated syndrome subjects with T2 magnetic resonance imaging lesions had higher PK11195 BPND in normal-appearing white matter (P = 0.009) and their normal-appearing white matter PK11195 BPND correlated with the Expanded Disability Status Scale (P = 0.007; r = 0.672). At 2 years those who developed dissemination in space or multiple sclerosis, had higher PK11195 BPND in normal-appearing white matter at baseline (P = 0.007 and P = 0.048, respectively). Central grey matter PK11195 BPND was increased in subjects with clinically isolated syndrome compared to healthy controls but no difference was found in cortical grey matter PK11195 BPND. Microglial activation in clinically isolated syndrome normal-appearing white matter is diffusely increased compared with healthy control subjects and is further increased in those who have magnetic resonance imaging lesions. Furthermore microglial activation in clinically

Characterization of Staphylococcus caprae Clinical Isolates Involved in Human Bone and Joint Infections, Compared with Goat Mastitis Isolates.

PubMed

d'Ersu, J; Aubin, G G; Mercier, P; Nicollet, P; Bémer, P; Corvec, S

2016-01-01

Staphylococcus caprae is an emerging microorganism in human bone and joint infections (BJI). The aim of this study is to describe the features of S. caprae isolates involved in BJI (H for human) compared with those of isolates recovered in goat mastitis (A for animal). Fourteen isolates of each origin were included. Identifications were performed using a Vitek 2 GP ID card, tuf gene sequencing, and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) Vitek MS. Molecular typing was carried out using pulsed-field gel electrophoresis (PFGE) and DiversiLab technology. The crystal violet method was used to determine biofilm-forming ability. Virulence factors were searched by PCR. Vitek MS technology provides an accurate identification for the two types of isolates compared to that of gold-standard sequencing (sensitivity, 96.4%), whereas the Vitek 2 GP ID card was more effective for H isolates. Molecular typing methods revealed two distinct lineages corresponding to the origin despite few overlaps: H and A. In our experimental conditions, no significant difference was observed in biofilm production ability between H and A isolates. Nine isolates (5 H isolates and 4 A isolates) behaved as weak producers while one A isolate was a strong producer. Concerning virulence factors, the autolysin atlC and the serine aspartate adhesin (sdrZ) genes were detected in 24 isolates (86%), whereas the lipase gene was always detected, except in one H isolate (96%). The ica operon was present in 23 isolates (82%). Fibrinogen-binding (fbe) or collagen-binding (cna) genes were not detected by using primers designed for Staphylococcus aureus or Staphylococcus epidermidis, even in low stringency conditions. Although S. caprae probably remains underestimated in human infections, further studies are needed to better understand the evolution and the adaptation of this species to its host. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Clinically significant borderline resistance of sequential clinical isolates of Klebsiella pneumoniae.

PubMed

Wagenlehner, F M E; Heisig, P; Irtenkauf, C; Notka, F; Decker, J; Lehn, N; Linde, H

2003-10-01

Two sequential clinical isolates of Klebsiella pneumoniae (Kpn) were isolated from bronchoalveolar lavage fluid (Kpn#1) and sputum (Kpn#2) of a patient with pneumonia, complicated by anatomical and immunosuppressive problems due to Wegener's granulomatosis. Despite 4 weeks of systemic treatment with ciprofloxacin (CIP) Kpn#2 was isolated thereafter. A fluoroquinolone-resistant mutant (Kpn#1-SEL) was derived from Kpn#1 in vitro by selecting on agar plates supplemented with ofloxacin. Kpn#1, Kpn#1-SEL and Kpn#2 had an identical pattern in PFGE. CIP MICs were 0.25, 2 and 4 mg/l for Kpn#1, Kpn#2 and Kpn#1-SEL, respectively. Kpn ATCC 10031 (CIP MIC 0.002 mg/l) served as control. We analyzed mechanisms of fluoroquinolone resistance by determining antibiotic susceptibility, organic solvent tolerance, accumulation of fluoroquinolones, dominance testing with wild-type topoisomerase genes (gyrA/B, parC/E), sequencing of the quinolone resistance determining regions of gyrA/B, parC/E and marR and Northern blotting of marR and acrAB genes. Compared with Kpn ATCC 10031, elevated MICs to fluoroquinolones and unrelated antibiotics in Kpn#1 was presumably due to a primary efflux pump other than AcrAB and increased the CIP MIC 125-fold. Although Kpn#1 tested sensitive according to NCCLS breakpoints, the elevated CIP MIC of 0.25 mg/l presumably rendered this isolate clinically resistant and lead to therapeutic failure in this case. Further increase of MIC to fluoroquinolones in vivo and in vitro was distinct. Kpn#1-SEL, selected in vitro, acquired a GyrA target mutation, whereas in Kpn#2 no known resistance mechanism could be detected.

Isolation of New Aureobasidium Strains That Produce High-Molecular-Weight Pullulan with Reduced Pigmentation

PubMed Central

Pollock, Thomas J.; Thorne, Linda; Armentrout, Richard W.

1992-01-01

New isolates of Aureobasidium pullulans were obtained from plant leaf surfaces gathered in San Diego County. The new fungal isolates were identified as A. pullulans on the basis of the appearance of polymorphic colonies formed on agar plates, the electrophoretic profiles of repeated genomic DNA sequences, and the production of pullulan in shake flask cultures. The isolates showed different degrees of pigmentation. One of the natural isolates was nonpigmented under mock production conditions in liquid culture, but was still able to synthesize a reduced amount of pigment on agar plates at late times. A mutagenic treatment with ethidium bromide produced derivatives of normally pigmented natural isolates that exhibited an increased tendency toward yeastlike growth and reduced pigmentation. Additionally, some of the new isolates and mutant derivatives accumulated pullulan of relatively high molecular weight in the culture broths. Images PMID:16348676

Antimicrobial resistance among aerobic biofilm producing bacteria isolated from chronic wounds in the tertiary care hospitals of Peshawar, Pakistan.

PubMed

Rahim, K; Qasim, M; Rahman, H; Khan, T A; Ahmad, I; Khan, N; Ullah, A; Basit, A; Saleha, S

2016-08-01

Chronic wound infections impose major medical and economic costs on health-care systems, cause significant morbidity, mortality and prolonged hospitalisation. The presence of biofilm producing bacteria in these wounds is considered as an important virulence factor that leads to chronic implications including ulceration. The undertaken study aimed to isolate and identify the biofilm aerobic bacterial pathogens from patients with chronic wound infections, and determine their antibiotics resistance profiles Method: During this study, swab specimens were collected from patients with chronic wounds at teaching hospitals of Peshawar, Pakistan between May 2013 and June 2014. The isolated aerobic bacterial pathogens were identified on the basis of standard cultural characteristics and biochemical tests. Antibiotics resistance profiles of biofilm producing bacteria against selected antibiotics were then determined. Among the chronic wound infections, diabetic foot ulcers were most common 37 (37%), followed by surgical ulcers 27 (27%). Chronic wounds were common in male patients older than 40 years. Among the total 163 isolated bacterial pathogens the most prevalent bacterial species were Pseudomonas aeruginosa 44 (27%), Klebsiella pneumoniae 26 (16%), Staphylococcus species 22 (14%) and Streptococcus spp. 21 (13%). The isolation rate of bacterial pathogens was high among patients with diabetic foot ulcers 83 (50.9%). Among bacterial isolates, 108 (66.2%) were observed as biofilm producers while 55 (33.8%) did not form biofilm in our model. The investigated biofilm producing bacterial isolates showed comparatively high resistance against tested antibiotics compared to non-biofilm producing bacterial isolates. The most effective antibiotics were amikacine and cefepime against all isolates. Increased multidrug resistance in biofilm producing bacteria associated with chronic wounds was observed in this study. Judicious use of antibiotics is needed to control the wound

Clinical resistance and decreased susceptibility in Streptococcus suis isolates from clinically healthy fattening pigs.

PubMed

Callens, Bénédicte F; Haesebrouck, Freddy; Maes, Dominiek; Butaye, Patrick; Dewulf, Jeroen; Boyen, Filip

2013-04-01

Streptococcus suis (S. suis) has often been reported as an important swine pathogen and is considered as a new emerging zoonotic agent. Consequently, it is important to be informed on its susceptibility to antimicrobial agents. In the current study, the Minimum Inhibitory Concentration (MIC) population distribution of nine antimicrobial agents has been determined for nasal S. suis strains, isolated from healthy pigs at the end of the fattening period from 50 closed or semiclosed pig herds. The aim of the study was to report resistance based on both clinical breakpoints (clinical resistance percentage) and epidemiological cutoff values (non-wild-type percentage). Non-wild-type percentages were high for tetracycline (98%), lincomycin (92%), tilmicosin (72%), erythromycin (70%), tylosin (66%), and low for florfenicol (0%) and enrofloxacin (0.3%). Clinical resistance percentages were high for tetracycline (95%), erythromycin (66%), tylosin (66%), and low for florfenicol (0.3%) and enrofloxacin (0.3%). For tiamulin, for which no clinical breakpoint is available, 57% of the isolates did not belong to the wild-type population. Clinical resistance and non-wild-type percentages differed substantially for penicillin. Only 1% of the tested S. suis strains was considered as clinically resistant, whereas 47% of the strains showed acquired resistance when epidemiological cutoff values were used. In conclusion, MIC values for penicillin are gradually increasing, compared to previous reports, although pigs infected with strains showing higher MICs may still respond to treatment with penicillin. The high rate of acquired resistance against tiamulin has not been reported before. Results from this study clearly demonstrate that the use of different interpretive criteria contributes to the extent of differences in reported antimicrobial resistance results. The early detection of small changes in the MIC population distribution of isolates, while clinical failure may not yet be

Production and novel quantification of haemolysins produced by coagulase-negative staphylococci isolated from subclinical mastitis in sheep.

PubMed

Kanellos, T S; Burriel, A R

2002-07-01

Coagulase-negative staphylococci producing cell-damaging toxins were isolated from the milk of sheep with subclinical mastitis. The haemolytic activity of Coagulase-negative staphylococcal strains was assessed on solid and liquid culture media. More than 61% and 76% of the tested strains on solid media produced evidence of alpha- and delta- haemolysins and more than 78% produced synergistic haemolysis. However almost all isolates producing haemolysin in liquid culture media produced only very few units of haemolysin compared to the positive control of five Coagulase-positive strains of staphylococci. It was concluded that solid media are better for classifying Coagulase-negative staphylococci as producers or not of haemolysins, and liquid media for measuring the size of this activity within the first few hours of intramammary infection.

Exopolysaccharide-producing lactic acid bacteria strains from traditional Thai fermented foods: isolation, identification and exopolysaccharide characterization.

PubMed

Smitinont, T; Tansakul, C; Tanasupawat, S; Keeratipibul, S; Navarini, L; Bosco, M; Cescutti, P

1999-10-15

Lactic Acid Bacteria (LAB) isolated from various traditional Thai fermented foods were screened for exopolysaccharides (EPS) production. From 104 isolates, two rod-shaped and five coccal-shaped LAB were able to produce EPS from sucrose on solid media. However, only the cocci were capable of producing EPS in liquid media and these were identified as Pediococcus pentosaceus. Pediococcus pentosaceus strains AP-1 and AP-3 produced EPS in high yield. In liquid media containing sucrose as carbon source, the amount of EPS produced by AP-1 and AP-3 strains was 6.0 and 2.5 g/L, respectively. The isolated and purified EPSs were chemically characterized. On the basis of sugar composition, methylation analysis and nuclear magnetic resonance spectroscopy, both the EPSs were shown to belong to the same dextran class. In particular, both EPSs differed from linear dextran by branching through 3,6-di-Osubstituted alpha-D-glucopyranosyl residues. The EPS from P. pentosaceus AP-3 was characterized by a relatively higher degree of branching and by a higher molecular weight than that from P. pentosaceus AP-1.

Isolation and molecular characterization of Salmonella enterica serovar Javiana from food, environmental and clinical samples.

PubMed

Mezal, Ezat H; Stefanova, Rossina; Khan, Ashraf A

2013-06-03

A total of 50 Salmonella enterica serovar Javiana isolates, isolated from food, environmental and clinical samples, were analyzed for antibiotic resistance, presence of virulence genes, plasmids and plasmid replicon types. To assess the genetic diversity, pulsed-field gel electrophoresis (PFGE) fingerprinting and plasmid profiles were performed. All of the isolates were sensitive to chloramphenicol, nalidixic acid, and sulfisoxazole, and four isolates showed intermediate resistance to gentamicin or kanamycin. Eleven isolates, including representatives from each of the source types, were resistant to ampicillin. Four isolates from either clinical or environmental sources were resistant to tetracycline, while an additional 20 isolates showed intermediate resistance to this drug. Fourteen isolates, primarily from food sources, showed intermediate resistance to streptomycin. The S. Javiana isolates were screened by PCR for 17 virulence genes (spvB, spiA, pagC, msgA, invA, sipB, prgH, spaN, orgA, tolC, iroN, sitC, IpfC, sifA, sopB, cdtB, and pefA). All isolates were positive for nine to fourteen of these genes, but none were positive for pefA, spvB and lpfC, which are typically present on the Salmonella virulence plasmid. Seven of the virulence genes including cdtB were found in all 50 isolates, suggesting that S. Javiana from food and environmental sources had virulence similar to clinical isolates. Four clinical isolates and two food isolates carried one or more plasmids of approximately 30, 38, and 58 kb, with the 58 kb plasmids belonging to incompatibility group IncFIIA. Two clinical isolates carried IncI1 type mega plasmid (80 kb), and one clinical isolate carried plasmids of 4.5 and 7 kb. The PFGE profiles resulted 34 patterns in five clusters at a 90% similarity threshold. Our results indicate that S. Javiana isolates have a diverse clonal population among the clinical, food and environmental samples and this serotype possesses several virulent genes and plasmids

Characteristics of CTX-M Extended-Spectrum β-Lactamase-Producing Escherichia coli Strains Isolated from Multiple Rivers in Southern Taiwan

PubMed Central

Chen, Po-An; Hung, Chih-Hsin; Huang, Ping-Chih; Chen, Jung-Ren; Huang, I-Fei; Chen, Wan-Ling; Chiou, Yee-Hsuan; Hung, Wan-Yu

2016-01-01

Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli sequence type ST131 has emerged as the leading cause of community-acquired urinary tract infections and bacteremia worldwide. Whether environmental water is a potential reservoir of these strains remains unclear. River water samples were collected from 40 stations in southern Taiwan from February to August 2014. PCR assay and multilocus sequence typing (MLST) analysis were conducted to determine the CTX-M group and sequence type, respectively. In addition, we identified the seasonal frequency of ESBL-producing E. coli strains and their geographical relationship with runoffs from livestock and poultry farms between February and August 2014. ESBL-producing E. coli accounted for 30% of the 621 E. coli strains isolated from river water in southern Taiwan. ESBL-producing E. coli ST131 was not detected among the isolates. The most commonly detected strain was E. coli CTX-M group 9. Among the 92 isolates selected for MLST analysis, the most common ESBL-producing clonal complexes were ST10 and ST58. The proportion of ESBL-producing E. coli was significantly higher in areas with a lower river pollution index (P = 0.025) and regions with a large number of chickens being raised (P = 0.013). ESBL-producing E. coli strains were commonly isolated from river waters in southern Taiwan. The most commonly isolated ESBL-producing clonal complexes were ST10 and ST58, which were geographically related to chicken farms. ESBL-producing E. coli ST131, the major clone causing community-acquired infections in Taiwan and worldwide, was not detected in river waters. PMID:26773082

Isolation and partial characterization of cyclic lipopeptide antibiotics produced by Paenibacillus ehimensis B7.

PubMed

Huang, Zhaohui; Hu, Yu; Shou, Linfei; Song, Mingxu

2013-04-17

The prevalence of drug-resistant bacteria has encouraged the search for novel antimicrobial compounds. Food-associated microorganisms, as a source of new antibiotics, have recently received considerable attention. The objective of this study was to find novel antimicrobial agents produced by food microorganisms. A bacterial strain B7, which has potent antimicrobial activity, was isolated from a sample of dairy waste. This strain was identified as Paenibacillus ehimensis based on the 16S rRNA gene sequence analysis, physiological and biochemical characterization. Two active compounds (PE1 and PE2) were obtained from P. ehimensis B7. Mass spectrometry (MS) analysis showed that the molecular masses of PE1 and PE2 were 1,114 and 1,100 Da, respectively. The tandem MS and amino acid analysis indicated that PE1 and PE2 were analogs of polypeptin, and PE2 was characterized as a new member of this family. Both compounds were active against all tested bacterial pathogens, including methicillin resistant Staphylococcus aureus, Escherichia coli, and pan-drug resistant Pseudomonas aeruginosa clinical isolate. Time-kill assays demonstrated that at 4 × MIC (minimum inhibitory concentration), PE1 and PE2 rapidly reduced the number of viable cells by at least 3-orders of magnitude, indicating that they were bactericidal antibiotics. In the present work, two cationic lipopeptide antibiotics (PE1 and PE2) were isolated from P. ehimensis B7 and characterized. These two peptides showed broad antimicrobial activity against all tested human pathogens and are worthy of further study.

Isolation and partial characterization of cyclic lipopeptide antibiotics produced by Paenibacillus ehimensis B7

PubMed Central

2013-01-01

Background The prevalence of drug-resistant bacteria has encouraged the search for novel antimicrobial compounds. Food-associated microorganisms, as a source of new antibiotics, have recently received considerable attention. The objective of this study was to find novel antimicrobial agents produced by food microorganisms. Results A bacterial strain B7, which has potent antimicrobial activity, was isolated from a sample of dairy waste. This strain was identified as Paenibacillus ehimensis based on the 16S rRNA gene sequence analysis, physiological and biochemical characterization. Two active compounds (PE1 and PE2) were obtained from P. ehimensis B7. Mass spectrometry (MS) analysis showed that the molecular masses of PE1 and PE2 were 1,114 and 1,100 Da, respectively. The tandem MS and amino acid analysis indicated that PE1 and PE2 were analogs of polypeptin, and PE2 was characterized as a new member of this family. Both compounds were active against all tested bacterial pathogens, including methicillin resistant Staphylococcus aureus, Escherichia coli, and pan-drug resistant Pseudomonas aeruginosa clinical isolate. Time-kill assays demonstrated that at 4 × MIC (minimum inhibitory concentration), PE1 and PE2 rapidly reduced the number of viable cells by at least 3-orders of magnitude, indicating that they were bactericidal antibiotics. Conclusions In the present work, two cationic lipopeptide antibiotics (PE1 and PE2) were isolated from P. ehimensis B7 and characterized. These two peptides showed broad antimicrobial activity against all tested human pathogens and are worthy of further study. PMID:23594351

Adult Vampire Bats Produce Contact Calls When Isolated: Acoustic Variation by Species, Population, Colony, and Individual

PubMed Central

Carter, Gerald G.; Logsdon, Ryane; Arnold, Bryan D.; Menchaca, Angelica; Medellin, Rodrigo A.

2012-01-01

Background Bat pups produce individually distinct isolation calls to facilitate maternal recognition. Increasing evidence suggests that, in group-living bat species, adults often use similar calls to maintain contact. We investigated if isolated adults from all three species of the highly cooperative vampire bats (Phyllostomidae: Desmodontinae) would produce vocally distinct contact calls when physically isolated. Methods/Principal Findings We assessed variation in contact calls recorded from isolated captive and wild-caught adult common vampire bats (Desmodus rotundus), white-winged vampire bats (Diaemus youngi) and hairy-legged vampire bats (Diphylla ecaudata). We compared species-typical contact call structure, and used information theory and permuted discriminate function analyses to examine call structure variation, and to determine if the individuality of contact calls is encoded by different call features across species and populations. We found that isolated adult vampire bats produce contact calls that vary by species, population, colony, and individual. However, much variation occurred within a single context and individual. We estimated signature information for captive Diaemus (same colony), captive Desmodus (same colony), and wild Desmodus (different colonies) at 3.21, 3.26, and 3.88 bits, respectively. Contact calls from a captive colony of Desmodus were less individually distinct than calls from wild-caught Desmodus from different colonies. Both the degree of individuality and parameters encoding individuality differed between the bats from a single captive colony and the wild-caught individuals from different groups. This result is consistent with, but not sufficient evidence of, vocal convergence in groups. Conclusion Our results show that adult vampire bats of all three species produce highly variable contact calls when isolated. Contact calls contain sufficient information for vocal discrimination, but also possess more intra-individual variation

Antimicrobial resistance in Escherichia coli and Salmonella spp. isolates from fresh produce and the impact to food safety.

PubMed

Vital, Pierangeli G; Caballes, Marie Bernadine D; Rivera, Windell L

2017-09-02

Foodborne diseases associated with fresh produce consumption have escalated worldwide, causing microbial safety of produce of critical importance. Bacteria that have increasingly been detected in fresh produce are Escherichia coli and Salmonella spp., both of which have been shown to progressively display antimicrobial resistance. The study focused on the assessment of antimicrobial resistance of these enteric bacteria from different kinds of fresh produce from various open air markets and supermarkets in the Philippines. Using the disk diffusion assay on a total of 50 bacterial isolates obtained from 410 fresh produce surveyed, monoresistance to tetracycline was observed to be the most prevalent (38%), followed by multidrug resistance to tetracycline, chloramphenicol, ciprofloxacin, and nalidixic acid (4%), and lastly by dual resistance to tetracycline and chloramphenicol (2%). Using multiplex and simplex polymerase chain reaction (PCR) assays, tetA (75%) and tetB (9%) were found in tetracycline resistant isolates, whereas catI (67%) and catIII (33%) were detected in chloramphenicol resistant isolates. Sequence analysis of gyr and par genes from the ciprofloxacin and nalidixic acid resistant isolates revealed different mutations. Based on the results, fresh produce act as a reservoir of these antibiotic resistant bacteria which may pose health threat to consumers.

Association of pellicle growth morphological characteristics and clinical presentation of Mycobacterium tuberculosis isolates.

PubMed

Arora, Ranjana; Armitige, Lisa; Wanger, Audrey; Hunter, Robert L; Hwang, Shen-An

2016-12-01

Trehalose 6,6'dimycolate (TDM) is a glycolipid found in nearly pure form on the surface of virulent Mycobacterium tuberculosis (MTB). This manuscript investigated the production of TDM, growth rate and colony morphology of multiple strains of MTB, each of which had been isolated from both pulmonary (sputum) and extrapulmonary sites of multiple patients. Since sputum contains MTB primarily from cavities and extrapulmonary biopsies are typically granulomas, this provided an opportunity to compare the behavior of single strains of MTB that had been isolated from cavities and granulomas. The results demonstrated that MTB isolated from pulmonary sites produced more TDM (3.23 ± 1.75 μg TDM/mg MTB), grew more rapidly as thin spreading pellicles, demonstrated early cording, and climbed culture well walls. In contrast, extrapulmonary isolates produced less TDM (1.42 ± 0.58 μg TDM/mg MTB) (p < 0.001) and grew as discrete patches with little tendency to spread or climb. Both Beijing pulmonary isolates and the non-Beijing pulmonary isolates produced significantly more TDM (1.64 ± 0.46 μg TDM/mg MTB) and grew faster than the Beijing and non-Beijing extrapulmonary isolates (1.14 ± 0.63 μg TDM/mg MTB) (p < 0.001 and p < 0.005 respectively). These results indicate that MTB from pulmonary sites (cavities) grows faster and produces more TDM than strains isolated from extrapulmonary sites (granulomas). This report suggests a critical role for TDM in cavitary TB. Copyright © 2016 Elsevier Ltd. All rights reserved.

Dual Toxin-Producing Strain of Clostridium botulinum Type Bf Isolated from a California Patient with Infant Botulism

PubMed Central

Barash, Jason R.; Arnon, Stephen S.

2004-01-01

A retrospective study of Clostridium botulinum strains isolated from patients from California with infant botulism identified the fourth known C. botulinum strain that produces both type B and type F botulinum toxins. This unique strain represented 0.12% of the California infant botulism case isolates from 1976 to 2003. The relative concentrations of type B and F toxins produced were temperature dependent. PMID:15071029

Increased cefepime MIC for enterobacteriacae clinical isolates.

PubMed

Najafi, Narges; Alikhani, Ahmad; Babamahmoudi, Farhang; Davoudi, Alireza; Ghasemiyan, Roya; Aliyan, Shahriar; Shoujaiifar, Arman

2013-01-01

Background : Cefepime was used as empirical treatment in ventilator-associated pneumonia (VAP) induced by gram-negative and gram-positive bacteria. This study aimed to determine the antimicrobial susceptibility pattern of cefepime against microorganism causing VAP in Mazandaran, North of Iran. This study was performed on VAP patients diagnosed with clinical pulmonary infection score (CPIS) scores in ICU of two hospitals. For each patient suspected of having VAP, quantitative culture of endotracheal aspiration (QEA) was performed and MIC was determined by micro dilution test. Data were collected and analyzed. Thirty- five cases of enterobacteriaceae were isolated orderly including E coli 13, P. aeruginosa 11, Enterobacter 7 and K. pneumonia 4 cases. All the isolated E. coli, Enterobacter and Klebsiella, 54.5% of P. aeruginosa isolated were fully resistant to cefepime. The results of this study show that cefepime is not a reasonable choice for empirical treatment of nosocomial pneumonia and VAP.

Differences in the API 20E biochemical patterns of clinical and environmental Vibrio parahaemolyticus isolates.

PubMed

Martinez-Urtaza, Jaime; Lozano-Leon, Antonio; Viña-Feas, Alejandro; de Novoa, Jacobo; Garcia-Martin, Oscar

2006-02-01

Genetic differences in clinical and environmental strains of Vibrio parahaemolyticus have been widely used as criteria in identifying pathogenic isolates. However, few studies have been carried out to assess the differences in biochemical characteristics of V. parahaemolyticus isolates from human and environmental sources. We compared the biochemical profiles obtained by the characterization of V. parahaemolyticus isolates from human infections and the marine environment using the API 20E system. Environmental and clinical isolates showed significant differences in the gelatin and arabinose tests. Additionally, clinical isolates were correctly identified according to the API 20E profile using 0.85% NaCl diluent, but they presented nonspecific profiles with 2% NaCl diluent. In contrast, use of 2% NaCl diluent facilitated correct identification of the environmental isolates. Clinical isolates showed significant differences in up to five biochemical tests with respect to the API 20E database. The API 20E system is widely used in routine identification of bacteria in clinical laboratories, and this discrepancy in an important number of biochemical tests may lead to misidentification of V. parahaemolyticus infection.

Identification of hemolysin BL-producing Bacillus cereus isolates by a discontinuous hemolytic pattern in blood agar.

PubMed Central

Beecher, D J; Wong, A C

1994-01-01

Bacillus cereus causes distinct exotoxin-mediated diarrheal and emetic food poisoning syndromes and a variety of nongastrointestinal infections. Evidence is accumulating that hemolysin BL is a major B. cereus virulence factor. We describe two methods for detection of hemolysin BL in crude samples and on primary culture media. In the first method, the highly unusual discontinuous hemolysis pattern that is characteristic of pure hemolysin BL was produced in sheep and calf blood agar around wells filled with crude culture supernatant from hemolysin BL-producing strains. In the second method, the pattern was formed surrounding colonies of hemolysin BL-producing strains grown on media consisting of nutrient agar, 0.15 M NaCl, 2% calf serum, and sheep or calf blood. Hemolysin BL production was detected with these methods in 41 of 62 (66%) previously identified B. cereus isolates and in 46 of 136 (34%) presumptive B. cereus isolates from soil. All nine isolates tested that were associated with diarrhea or nongastrointestinal illness were positive for hemolysin BL. The methods presented here are specific, simple, inexpensive, and applicable to the screening of large numbers of samples or isolates. Images PMID:8017944

Characterization of Five Fungal Endophytes Producing Cajaninstilbene Acid Isolated from Pigeon Pea [Cajanus cajan (L.) Millsp.

PubMed Central

Zu, Yuan Gang; Fu, Yu Jie; Wang, Wei; Luo, Meng; Efferth, Thomas

2011-01-01

Five fungal endophytes (K4, K5, K6, K9, K14) producing Cajaninstilbene acid (CSA, 3-hydroxy-4-prenyl-5-methoxystilbene-2-carboxylic acid) were isolated from the roots of pigeon pea [Cajanus cajan (L.) Millsp.]. CSA is responsible for the prominent pharmacological activities in pigeon pea. The amount of CSA in culture solution varied among the five fungal endophytes. K4 produced the highest levels of CSA (1037.13 µg/L) among the endophytes tested after incubation for five days. Both morphological characteristics and molecular methods were used for species identification of fungal endophytes. The five endophytic isolates were characterized by analyzing the internal transcribed spacer (ITS) rRNA and β-tubulin genes. The K4, K5, K9 and K14 strains isolated from pigeon pea roots were found to be closely related to the species Fusarium oxysporum. K6 was identified as Neonectria macrodidym. The present study is the first report on the isolation and identification of fungal endophytes producing CSA in pigeon pea. The study also provides a scientific base for large scale production of CSA. PMID:22102911

Incidence of bovine clinical mastitis in Jammu region and antibiogram of isolated pathogens.

PubMed

Bhat, Adil Majid; Soodan, Jasvinder Singh; Singh, Rajiv; Dhobi, Ishfaq Ahmad; Hussain, Tufail; Dar, Mohammad Yousuf; Mir, Muheet

2017-08-01

This study was conducted to evaluate the incidence of clinical mastitis in bovines of Jammu region, to identify the infectious organisms responsible for it, and the antimicrobial sensitivity of isolated pathogens. The study was conducted on cases that were presented to the Medicine Division of Teaching Veterinary Clinical Complex, Faculty of Veterinary Sciences and Animal Husbandry, R.S. Pura, Jammu, Jammu and Kashmir. A total of 260 cases of bovines were presented from June 30, 2012, to July 01, 2013, out of which 30 cases were of clinical mastitis. The diagnosis of clinical mastitis was made on the basis of history and clinical examination of affected animals. Animal and quarter-wise incidence of clinical mastitis were found to be 11.5% and 5.76%, respectively. Of the 23 isolates obtained, Staphylococcus aureus (60.87%) was the most frequently isolated organism, followed by coagulase negative Staphylococci (13.04%), Streptococcus uberis (4.35%), Streptococcus dysgalactiae (8.69%), and Escherichia coli (13.04%). The antimicrobial sensitivity of isolates revealed maximum sensitivity to enrofloxacin, gentamicin, amoxicillin/sulbactam, ceftriaxone/tazobactam, ceftizoxime, ampicillin/sulbactam and least sensitivity for oxytetracycline and penicillin. Staphylococcus spp. is the major causative agent of clinical mastitis in bovines of Jammu region. The causative agents of the clinical mastitis were most sensitive to enrofloxacin and gentamicin.

Occurrence of Carbapenemase-Producing Enterobacteriaceae Isolates in the Wildlife: First Report of OXA-48 in Wild Boars in Algeria.

PubMed

Bachiri, Taous; Bakour, Sofiane; Lalaoui, Rym; Belkebla, Nadia; Allouache, Meriem; Rolain, Jean Marc; Touati, Abdelaziz

2018-04-01

The aim of the present study was to screen for the presence of carbapenemase-producing Enterobacteriaceae (CPE) isolates from wild boars and Barbary macaques in Algeria. Fecal samples were collected from wild boars (n = 168) and Barbary macaques (n = 212), in Bejaia, Algeria, between September 2014 and April 2016. The isolates were identified and antimicrobial susceptibility was determined. Carbapenem resistance determinants were studied using PCR and sequencing, while clonal relatedness was performed using multilocus sequence typing (MLST). PCR was used to investigate certain virulence genes. Three CPE isolates from three different samples (1.8%) recovered from wild boars were identified as Escherichia coli (two isolates) and Klebsiella pneumoniae (one isolate). These isolates were resistant to amoxicillin, amoxicillin-clavulanate, tobramycin, ertapenem, and meropenem. The results of PCR and sequencing analysis showed that all three isolates produced the OXA-48 enzyme. The MLST showed that the two E. coli isolates were assigned to the same sequence type, ST635, and belonged to phylogroup A, whereas K. pneumoniae strain belonged to ST13. The K. pneumoniae strain was positive for multiple virulence factors, whereas no virulence determinants were found in E. coli isolates. This is the first report of OXA-48-producing Enterobacteriaceae in wild animals from Algeria and Africa.

Molecular mechanisms of membrane impermeability in clinical isolates of Enterobacteriaceae exposed to imipenem selective pressure.

PubMed

Pavez, Monica; Vieira, Camila; de Araujo, Maria Rita; Cerda, Alvaro; de Almeida, Lara Mendes; Lincopan, Nilton; Mamizuka, Elsa Masae

2016-07-01

Intrinsic mechanisms leading to carbapenem-induced membrane impermeability and multidrug resistance are poorly understood in clinical isolates of Enterobacteriaceae. In this study, molecular behaviours during the establishment of membrane impermeability in members of the Enterobacteriaceae family under imipenem selective pressure were investigated. Clinical isolates (n = 22) exhibiting susceptibility to multiple antibiotics or characterised as extended-spectrum β-lactamase (ESBL)- or AmpC-producers were submitted to progressive passages on Mueller-Hinton agar plates containing subclinical concentrations of imipenem [0.5 × the minimum inhibitory concentration (MIC)]. Changes in outer membrane permeability were evaluated by determination of antimicrobial MICs, sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), and gene expression analysis related to membrane permeability (i.e. omp35-like, omp36-like and acrA) and regulatory mechanisms (i.e. marA and ompR) by quantitative reverse transcription PCR. Following imipenem induction, 73% of isolates showed increased carbapenem MICs by ≥2 doubling dilutions. At an early stage of treatment, imipenem modulated the expression of porins and efflux pump genes, represented by a reduction of 78% in omp36-like and a two-fold increase in acrA expression. Transcriptional factors marA and ompR were also affected by imipenem induction, increasing mRNA expression by 14- and 4-fold, respectively. High marA expression levels were associated with higher values of acrA expression. These results suggest that imipenem is an important factor in the development of an adaptive response to carbapenems by regulating key genes involved in the control of efflux pumps and porins, which could lead to a multidrug-resistant profile in clinical isolates, contributing to possible treatment failure. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

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.

Identification of syncytial mutations in a clinical isolate of herpes simplex virus 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muggeridge, Martin I.; Grantham, Michael L.; Center for Molecular and Tumor Virology, Louisiana State University Health Sciences Center, Shreveport, LA 71130

2004-10-25

Small polykaryocytes resulting from cell fusion are found in herpes simplex virus (HSV) lesions in patients, but their significance for viral spread and pathogenesis is unclear. Although syncytial variants causing extensive fusion in tissue culture can be readily isolated from laboratory strains, they are rarely found in clinical isolates, suggesting that extensive cell fusion may be deleterious in vivo. Syncytial mutations have previously been identified for several laboratory strains, but not for clinical isolates of HSV type 2. To address this deficiency, we studied a recent syncytial clinical isolate, finding it to be a mixture of two syncytial and onemore » nonsyncytial strain. The two syncytial strains have novel mutations in glycoprotein B, and in vitro cell fusion assays confirmed that they are responsible for syncytium formation. This panel of clinical strains may be ideal for examining the effect of increased cell fusion on pathogenesis.« less

Antimicrobial resistance levels amongst staphylococci isolated from clinical cases of bovine mastitis in Kosovo.

PubMed

Mehmeti, Ibrahim; Behluli, Behlul; Mestani, Mergim; Ademi, Arsim; Nes, Ingolf F; Diep, Dzung B

2016-10-31

Mastitis is one of the most frequent and costly disease in cattle. We studied milk samples from cattle with mastitis from farms in Kosovo to identify mastitis-causing pathogens and possible effective antibiotics. Our ultimate goal is to help implement adequate antibiotic management and treatment practices in Kosovo METHODOLOGY: A total of 152 milk samples were collected from cows with clinical mastitis from different farms in Kosovo. After identification of microorganisms, antibiotic susceptibility and the occurrence of enterotoxins was investigated. Staphylococci were found in 89 samples, of which 58 were coagulase negative and 31 coagulase positive. S. aureus was isolated from 27 samples, S. epidermidis from 25, and S. chromogenes from 15, while other species of staphylococci were isolated from the remaining 22 isolates. Interestingly, the bacterial diversity was different between cows in different periods of lactation and among different breeds. Most of the isolates (76/89) were resistant to two or more antibiotics. The highest resistance was to penicillin and ampicillin (> 65%), followed by tetracycline, oxacillin, streptomycin, chloramphenicol (> 23%), and less than 3% to erythromycin. Of the 89 isolates, 40 produced enterotoxins that were most frequently typed as A and C. We detected human bacterial pathogens in the cultures of milk samples from cows with mastitis. The isolates demonstrated resistance to two or more antibiotics, some of which are frequently used to treat animal and human infections. We recommend increased control and more stringent use of antibiotics in veterinary as well as human medicine.

Anaerococcus degenerii sp. nov., isolated from human clinical specimens.

PubMed

Veloo, A C M; Elgersma, P E; van Winkelhoff, A J

2015-06-01

Four clinical isolates of gram-positive strict anaerobic cocci were isolated from four different human mixed anaerobic infections. The taxonomical status of the four strains could not be established using standard identification techniques. The biochemical features of the strains were established and their taxonomic position was determined using 16S rRNA sequencing. The four strains form a homogeneous phenotypical and genotypical cluster. A new Anaerococcus species is proposed for these isolates: Anaerococcus degenerii sp. nov. The type strain is UMCG-104(T) = DSM29674(T) (accession number AM176528). Copyright © 2015 Elsevier Ltd. All rights reserved.

Increased PK11195-PET binding in normal-appearing white matter in clinically isolated syndrome.

PubMed

Giannetti, Paolo; Politis, Marios; Su, Paul; Turkheimer, Federico E; Malik, Omar; Keihaninejad, Shiva; Wu, Kit; Waldman, Adam; Reynolds, Richard; Nicholas, Richard; Piccini, Paola

2015-01-01

The most accurate predictor of the subsequent development of multiple sclerosis in clinically isolated syndrome is the presence of lesions at magnetic resonance imaging. We used in vivo positron emission tomography with (11)C-(R)-PK11195, a biomarker of activated microglia, to investigate the normal-appearing white matter and grey matter of subjects with clinically isolated syndrome to explore its role in the development of multiple sclerosis. Eighteen clinically isolated syndrome and eight healthy control subjects were recruited. Baseline assessment included: history, neurological examination, expanded disability status scale, magnetic resonance imaging and PK11195-positron emission tomography scans. All assessments except the PK11195-positron emission tomography scan were repeated over 2 years. SUPERPK methodology was used to measure the binding potential relative to the non-specific volume, BPND. We show a global increase of normal-appearing white matter PK11195 BPND in clinically isolated syndrome subjects compared with healthy controls (P = 0.014). Clinically isolated syndrome subjects with T2 magnetic resonance imaging lesions had higher PK11195 BPND in normal-appearing white matter (P = 0.009) and their normal-appearing white matter PK11195 BPND correlated with the Expanded Disability Status Scale (P = 0.007; r = 0.672). At 2 years those who developed dissemination in space or multiple sclerosis, had higher PK11195 BPND in normal-appearing white matter at baseline (P = 0.007 and P = 0.048, respectively). Central grey matter PK11195 BPND was increased in subjects with clinically isolated syndrome compared to healthy controls but no difference was found in cortical grey matter PK11195 BPND. Microglial activation in clinically isolated syndrome normal-appearing white matter is diffusely increased compared with healthy control subjects and is further increased in those who have magnetic resonance imaging lesions. Furthermore microglial activation in clinically

Resistome of carbapenem- and colistin-resistant Klebsiella pneumoniae clinical isolates.

PubMed

Lomonaco, Sara; Crawford, Matthew A; Lascols, Christine; Timme, Ruth E; Anderson, Kevin; Hodge, David R; Fisher, Debra J; Pillai, Segaran P; Morse, Stephen A; Khan, Erum; Hughes, Molly A; Allard, Marc W; Sharma, Shashi K

2018-01-01

The emergence and dissemination of carbapenemases, bacterial enzymes able to inactivate most β-lactam antibiotics, in Enterobacteriaceae is of increasing concern. The concurrent spread of resistance against colistin, an antibiotic of last resort, further compounds this challenge further. Whole-genome sequencing (WGS) can play a significant role in the rapid and accurate detection/characterization of existing and emergent resistance determinants, an essential aspect of public health surveillance and response activities to combat the spread of antimicrobial resistant bacteria. In the current study, WGS data was used to characterize the genomic content of antimicrobial resistance genes, including those encoding carbapenemases, in 10 multidrug-resistant Klebsiella pneumoniae isolates from Pakistan. These clinical isolates represented five sequence types: ST11 (n = 3 isolates), ST14 (n = 3), ST15 (n = 1), ST101 (n = 2), and ST307 (n = 1). Resistance profiles against 25 clinically-relevant antimicrobials were determined by broth microdilution; resistant phenotypes were observed for at least 15 of the 25 antibiotics tested in all isolates except one. Specifically, 8/10 isolates were carbapenem-resistant and 7/10 isolates were colistin-resistant. The blaNDM-1 and blaOXA-48 carbapenemase genes were present in 7/10 and 5/10 isolates, respectively; including 2 isolates carrying both genes. No plasmid-mediated determinants for colistin resistance (e.g. mcr) were detected, but disruptions and mutations in chromosomal loci (i.e. mgrB and pmrB) previously reported to confer colistin resistance were observed. A blaOXA-48-carrying IncL/M-type plasmid was found in all blaOXA-48-positive isolates. The application of WGS to molecular epidemiology and surveillance studies, as exemplified here, will provide both a more complete understanding of the global distribution of MDR isolates and a robust surveillance tool useful for detecting emerging threats to public health.

Resistome of carbapenem- and colistin-resistant Klebsiella pneumoniae clinical isolates

PubMed Central

Crawford, Matthew A.; Lascols, Christine; Timme, Ruth E.; Anderson, Kevin; Hodge, David R.; Fisher, Debra J.; Pillai, Segaran P.; Morse, Stephen A.; Khan, Erum; Hughes, Molly A.; Allard, Marc W.; Sharma, Shashi K.

2018-01-01

The emergence and dissemination of carbapenemases, bacterial enzymes able to inactivate most β-lactam antibiotics, in Enterobacteriaceae is of increasing concern. The concurrent spread of resistance against colistin, an antibiotic of last resort, further compounds this challenge further. Whole-genome sequencing (WGS) can play a significant role in the rapid and accurate detection/characterization of existing and emergent resistance determinants, an essential aspect of public health surveillance and response activities to combat the spread of antimicrobial resistant bacteria. In the current study, WGS data was used to characterize the genomic content of antimicrobial resistance genes, including those encoding carbapenemases, in 10 multidrug-resistant Klebsiella pneumoniae isolates from Pakistan. These clinical isolates represented five sequence types: ST11 (n = 3 isolates), ST14 (n = 3), ST15 (n = 1), ST101 (n = 2), and ST307 (n = 1). Resistance profiles against 25 clinically-relevant antimicrobials were determined by broth microdilution; resistant phenotypes were observed for at least 15 of the 25 antibiotics tested in all isolates except one. Specifically, 8/10 isolates were carbapenem-resistant and 7/10 isolates were colistin-resistant. The blaNDM-1 and blaOXA-48 carbapenemase genes were present in 7/10 and 5/10 isolates, respectively; including 2 isolates carrying both genes. No plasmid-mediated determinants for colistin resistance (e.g. mcr) were detected, but disruptions and mutations in chromosomal loci (i.e. mgrB and pmrB) previously reported to confer colistin resistance were observed. A blaOXA-48-carrying IncL/M-type plasmid was found in all blaOXA-48-positive isolates. The application of WGS to molecular epidemiology and surveillance studies, as exemplified here, will provide both a more complete understanding of the global distribution of MDR isolates and a robust surveillance tool useful for detecting emerging threats to public health. PMID:29883490

Characteristics of CTX-M Extended-Spectrum β-Lactamase-Producing Escherichia coli Strains Isolated from Multiple Rivers in Southern Taiwan.

PubMed

Chen, Po-An; Hung, Chih-Hsin; Huang, Ping-Chih; Chen, Jung-Ren; Huang, I-Fei; Chen, Wan-Ling; Chiou, Yee-Hsuan; Hung, Wan-Yu; Wang, Jiun-Ling; Cheng, Ming-Fang

2016-01-15

Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli sequence type ST131 has emerged as the leading cause of community-acquired urinary tract infections and bacteremia worldwide. Whether environmental water is a potential reservoir of these strains remains unclear. River water samples were collected from 40 stations in southern Taiwan from February to August 2014. PCR assay and multilocus sequence typing (MLST) analysis were conducted to determine the CTX-M group and sequence type, respectively. In addition, we identified the seasonal frequency of ESBL-producing E. coli strains and their geographical relationship with runoffs from livestock and poultry farms between February and August 2014. ESBL-producing E. coli accounted for 30% of the 621 E. coli strains isolated from river water in southern Taiwan. ESBL-producing E. coli ST131 was not detected among the isolates. The most commonly detected strain was E. coli CTX-M group 9. Among the 92 isolates selected for MLST analysis, the most common ESBL-producing clonal complexes were ST10 and ST58. The proportion of ESBL-producing E. coli was significantly higher in areas with a lower river pollution index (P = 0.025) and regions with a large number of chickens being raised (P = 0.013). ESBL-producing E. coli strains were commonly isolated from river waters in southern Taiwan. The most commonly isolated ESBL-producing clonal complexes were ST10 and ST58, which were geographically related to chicken farms. ESBL-producing E. coli ST131, the major clone causing community-acquired infections in Taiwan and worldwide, was not detected in river waters. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Update on clinically isolated syndrome.

PubMed

Thouvenot, Éric

2015-04-01

Optic neuritis, myelitis and brainstem syndrome accompanied by a symptomatic MRI T2 or FLAIR hyperintensity and T1 hypointensity are highly suggestive of multiple sclerosis (MS) in young adults. They are called "clinically isolated syndrome" (CIS) and correspond to the typical first multiple sclerosis (MS) episode, especially when associated with other asymptomatic demyelinating lesions, without clinical, radiological and immunological sign of differential diagnosis. After a CIS, the delay of apparition of a relapse, which corresponds to the conversion to clinically definite MS (CDMS), varies from several months to more than 10 years (10-15% of cases, generally called benign RRMS). This delay is generally associated with the number and location of demyelinating lesions of the brain and spinal cord and the results of CSF analysis. Several studies comparing different MRI criteria for dissemination in space and dissemination in time of demyelinating lesions, two hallmarks of MS, provided enough substantial data to update diagnostic criteria for MS after a CIS. In the last revision of the McDonald's criteria in 2010, diagnostic criteria were simplified and now the diagnosis can be made by a single initial scan that proves the presence of active asymptomatic lesions (with gadolinium enhancement) and of unenhanced lesions. However, time to conversion remains highly unpredictable for a given patient and CIS can remain isolated, especially for idiopathic unilateral optic neuritis or myelitis. Univariate analyses of clinical, radiological, biological or electrophysiological characteristics of CIS patients in small series identified numerous risk factors of rapid conversion to MS. However, large series of CIS patients analyzing several characteristics of CIS patients and the influence of disease modifying therapies brought important information about the risk of CDMS or RRMS over up to 20 years of follow-up. They confirmed the importance of the initial MRI pattern of

Identification of Lactococcus-Specific Bacteriocins Produced by Lactococcal Isolates, and the Discovery of a Novel Bacteriocin, Lactococcin Z.

PubMed

Ishibashi, Naoki; Seto, Hiromi; Koga, Shoko; Zendo, Takeshi; Sonomoto, Kenji

2015-09-01

Lactic acid bacteria that produce Lactococcus-specific bacteriocins were isolated and identified as Lactococcus lactis from fresh corn or lettuce. Among them, four isolates were identified as lactococcin Q producers. Seven isolates showed antimicrobial activity against a lactococcin Q producer, L. lactis QU 4, as well as against nisin Z and lacticin Q producers belonging to L. lactis. Strain QU 7 was selected as a standard strain and showed no cross-immunity to lactococcin Q or other lactococcal bacteriocins. The bacteriocin produced by strain QU 7 was purified in three chromatographic steps, and its molecular mass was determined to be 5041.35 Da. The amino acid sequence analysis revealed that it is a novel class IId bacteriocin, referred to as lactococcin Z. It consisted of 45 amino acid residues. The lczA gene encoding the prepeptide of lactococcin Z showed homology to lactococcins A, B, and M. Thus, this report demonstrates a new example of Lactococcus-specific bacteriocins.

Isolation and characterization of endophytic taxol-producing fungi from Taxus chinensis.

PubMed

Liu, Kaihui; Ding, Xiaowei; Deng, Baiwan; Chen, Wenqiang

2009-09-01

This study investigated the endophytic fungi diversity of Taxus chinensis and screened the taxol-producing fungi in the host. A total of 115 endophytic fungi isolates obtained from bark segments of T. chinensis were grouped into 23 genera based on the morphological traits and sequence analysis of the internal transcribed spacers (ITS1-5.8S-ITS2), indicating endophytic fungi in T. chinensis are diverse and abundant. Diaporthe, Phomopsis (anamorph of Diaporthe), Acremonium, and Pezicula were the dominant genera, whereas the remaining genera were infrequent groups. The 13 representative species of the distinct genera were capable of producing taxol verified by reverse-phase high performance liquid chromatography (HPLC). Among the taxol-producing fungi, the yield of taxol produced by the Metarhizium anisopliae, H-27 was 846.1 microg l(-1) in reformative potato dextrose liquid medium, and the fungal taxol was further validated by mass spectrometry (MS). The taxol-producing fungi (92.3%) were infrequent communities, suggesting that infrequent fungi associated with T. chinensis might be a fascinating reservoir of taxol-generating fungi.

Degenerate primer MOB typing of multiresistant clinical isolates of E. coli uncovers new plasmid backbones.

PubMed

Garcillán-Barcia, M Pilar; Ruiz del Castillo, Belén; Alvarado, Andrés; de la Cruz, Fernando; Martínez-Martínez, Luis

2015-01-01

Degenerate Primer MOB Typing is a PCR-based protocol for the classification of γ-proteobacterial transmissible plasmids in five phylogenetic relaxase MOB families. It was applied to a multiresistant E. coli collection, previously characterized by PCR-based replicon-typing, in order to compare both methods. Plasmids from 32 clinical isolates of multiresistant E. coli (19 extended spectrum beta-lactamase producers and 13 non producers) and their transconjugants were analyzed. A total of 95 relaxases were detected, at least one per isolate, underscoring the high potential of these strains for antibiotic-resistance transmission. MOBP12 and MOBF12 plasmids were the most abundant. Most MOB subfamilies detected were present in both subsets of the collection, indicating a shared mobilome among multiresistant E. coli. The plasmid profile obtained by both methods was compared, which provided useful data upon which decisions related to the implementation of detection methods in the clinic could be based. The phylogenetic depth at which replicon and MOB-typing classify plasmids is different. While replicon-typing aims at plasmid replication regions with non-degenerate primers, MOB-typing classifies plasmids into relaxase subfamilies using degenerate primers. As a result, MOB-typing provides a deeper phylogenetic depth than replicon-typing and new plasmid groups are uncovered. Significantly, MOB typing identified 17 plasmids and an integrative and conjugative element, which were not detected by replicon-typing. Four of these backbones were different from previously reported elements. Copyright © 2014 Elsevier Inc. All rights reserved.

Indentification of vincamine indole alkaloids producing endophytic fungi isolated from Nerium indicum, Apocynaceae.

PubMed

Na, Ren; Jiajia, Liu; Dongliang, Yang; Yingzi, Peng; Juan, Hong; Xiong, Liu; Nana, Zhao; Jing, Zhou; Yitian, Luo

2016-11-01

Vincamine, a monoterpenoid indole alkaloid which had been marketed as nootropic drugs for the treatment of cerebral insufficiencies, is widely found in plants of the Apocynaceae family. Nerium indicum is a plant belonging to the Apocynaceae family. So, the purpose of this research was designed to investigate the vincamine alkaloids producing endophytic fungi from Nerium indicum, Apocynaceae. 11 strains of endophytic fungi, isolated from the stems and roots of the plant, were grouped into 5 genera on the basis of morphological characteristics. All fungal isolates were fermented and their extracts were preliminary screened by Dragendorff's reagent and thin layer chromatography (TLC). One isolated strain CH1, isolated from the stems of Nerium indicum, had the same Rf value (about 0.56) as authentic vincamine. The extracts of strain CH1 were further analyzed by high performance liquid chromatography (HPLC) and liquid chromatograph-mass spectrometry (LC-MS), and the results showed that the strain CH1 could produce vincamine and vincamine analogues. The acetylcholinesterase (AchE) inhibitory activity assays using Ellman's method revealed that the metabolites of strain CH1 had significant AchE inhibitory activity with an IC50 value of 5.16μg/mL. The isolate CH1 was identified as Geomyces sp. based on morphological and molecular identification, and has been deposited in the China Center for Type Culture Collection (CCTCCM 2014676). This study first reported the natural compounds tabersonine and ethyl-vincamine from endophytic fungi CH1, Geomyces sp. In conclusion, the fungal endophytes from Nerium indicum can be used as alternative source for the production of vincamine and vincamine analogues. Copyright © 2016 Elsevier GmbH. All rights reserved.

Molecular characteristics of travel-related extended-spectrum-beta-lactamase-producing Escherichia coli isolates from the Calgary Health Region.

PubMed

Pitout, Johann D D; Campbell, Lorraine; Church, Deirdre L; Gregson, Daniel B; Laupland, Kevin B

2009-06-01

Extended-spectrum-beta-lactamase (ESBL)-producing Escherichia coli has recently emerged as a major risk factor for community-acquired, travel-related infections in the Calgary Health Region. Molecular characterization was done on isolates associated with infections in returning travelers using isoelectric focusing, PCR, and sequencing for bla(CTX-M)s, bla(TEM)s, bla(SHV)s, bla(OXA)s, and plasmid-mediated quinolone resistance determinants. Genetic relatedness was determined with pulsed-field gel electrophoresis using XbaI and multilocus sequence typing (MLST). A total of 105 residents were identified; 6/105 (6%) presented with hospital-acquired infections, 9/105 (9%) with health care-associated community-onset infections, and 90/105 (86%) with community-acquired infections. Seventy-seven of 105 (73%) of the ESBL-producing E. coli isolates were positive for bla(CTX-M) genes; 55 (58%) produced CTX-M-15, 13 (14%) CTX-M-14, six (6%) CTX-M-24, one (1%) CTX-M-2, one (1%) CTX-M-3, and one (1%) CTX-M-27, while 10 (10%) produced TEM-52, three (3%) TEM-26, 11 (11%) SHV-2, and four (4%) produced SHV-12. Thirty-one (30%) of the ESBL-producing E. coli isolates were positive for aac(6')-Ib-cr, and one (1%) was positive for qnrS. The majority of the ESBL-producing isolates (n = 95 [90%]) were recovered from urine samples, and 83 (87%) were resistant to ciprofloxacin. The isolation of CTX-M-15 producers belonging to clone ST131 was associated with travel to the Indian subcontinent (India, Pakistan), Africa, the Middle East, and Europe, while clonally unrelated strains of CTX-M-14 and -24 were associated with travel to Asia. Our study suggested that clone ST131 coproducing CTX-M-15, OXA-1, TEM-1, and AAC(6')-Ib-cr and clonally unrelated CTX-M-14 producers have emerged as important causes of community-acquired, travel-related infections.

Evaluation of the Microbial Identification System for identification of clinically isolated yeasts.

PubMed Central

Crist, A E; Johnson, L M; Burke, P J

1996-01-01

The Microbial Identification System (MIS; Microbial ID, Inc., Newark, Del.) was evaluated for the identification of 550 clinically isolated yeasts. The organisms evaluated were fresh clinical isolates identified by methods routinely used in our laboratory (API 20C and conventional methods) and included Candida albicans (n = 294), C. glabrata (n = 145), C. tropicalis (n = 58), C. parapsilosis (n = 33), and other yeasts (n = 20). In preparation for fatty acid analysis, yeasts were inoculated onto Sabouraud dextrose agar and incubated at 28 degrees C for 24 h. Yeasts were harvested, saponified, derivatized, and extracted, and fatty acid analysis was performed according to the manufacturer's instructions. Fatty acid profiles were analyzed, and computer identifications were made with the Yeast Clinical Library (database version 3.8). Of the 550 isolates tested, 374 (68.0%) were correctly identified to the species level, with 87 (15.8%) being incorrectly identified and 89 (16.2%) giving no identification. Repeat testing of isolates giving no identification resulted in an additional 18 isolates being correctly identified. This gave the MIS an overall identification rate of 71.3%. The most frequently misidentified yeast was C. glabrata, which was identified as Saccharomyces cerevisiae 32.4% of the time. On the basis of these results, the MIS, with its current database, does not appear suitable for the routine identification of clinically important yeasts. PMID:8880489

Molecular characterization of metallo β-lactamase producing multidrug resistant Pseudomonas aeruginosa from various clinical samples.

PubMed

Ramakrishnan, Kalaivani; Rajagopalan, Saranathan; Nair, Shashikala; Kenchappa, Prashanth; Chandrakesan, Sheela Devi

2014-01-01

Pseudomonas aeruginosa is a potent opportunistic nosocomial human pathogen among Gram-negative bacteria causing various life-threatening infections in patients from Intensive Care Units. This bacterium has become resistant to almost all commonly available antibiotics with limited treatment options. Multi drug resistant P. aeruginosa (MDRPA) is a major cause of concern among hospital acquired infections. It uses distinctive resistant mechanisms virtually to all the available antibiotics such as Metallo β-lactamases (MBL) production, extended spectrum β-lactamase production (ESBL), up regulation of efflux systems related genes and decreased outer membrane permeability. This study was carried out to find one the predominant resistance mechanisms among MDRPA and the prevalence of corresponding resistance genes. MDRPA isolates collected from various clinical samples for a period of 1-year (November 2009-Octo ber 2010) were included to detect the predominant mechanism of resistance using phenotypic and molecular methods. Molecular characterization of all these isolates was done by polymerase chain reaction (PCR) for the presence of blaVIM-₂, blaIMP-₁, blaOXA-₂₃, and blaNDM-₁ genes with specific primers. Among 75 MDRPA isolates 84% (63) were MBL producers. Molecular characterization studied by PCR showed the presence of blaVIM-₂ gene in 13% of MBL producers. The prevalence of MBLs has been increasing worldwide, particularly among P. aeruginosa, leading to severe limitations in the therapeutic options for the management. Thus, proper resistance screening measures and appropriate antibiotic policy can be strictly adopted by all the healthcare facility providers to overcome these superbugs.

Molecular identification of Aspergillus and Eurotium species isolated from rice and their toxin-producing ability.

PubMed

Yazdani, D; Zainal Abidin, M A; Tan, Y H; Kamaruzaman, S

2011-01-01

Thirty milled rice samples were collected from retailers in 4 provinces of Malaysia. These samples were evaluated for Aspergillus spp. infection by direct plating on malt extract salt agar (MESA). All Aspergillus holomorphs were isolated and identified using nucleotide sequences of ITS 1 and ITS 2 of rDNA. Five anamorphs (Aspergillus flavus, A. oryzae, A. tamarii, A. fumigatus and A. niger) and 5 teleomorphs (Eurotium rubrum, E. amstelodami, E. chevalieri, E. cristatum and E. tonophilum) were identified. The PCR-sequencing based technique for sequences of ITS 1 and ITS 2 is a fast technique for identification of Aspergillus and Eurotium species, although it doesn't work flawlessly for differentiation of Eurotium species. All Aspergillus and Eurotium isolates were screened for their ability to produce aflatoxin and ochratoxin A (OTA) by HPLC and TLC techniques. Only A. flavus isolate UPM 89 was able to produce aflatoxins B1 and B2.

Prevalence and Molecular Characterization of Plasmid-mediated Extended-Spectrum β-Lactamase Genes (balaTEM, blaCTX and blASHV) Among Urinary Escherichia coli Clinical Isolates in Mashhad, Iran

PubMed Central

Nakhaei Moghaddam, Mahboobeh; Forghanifard, Mohammad Mahdi; Moshrefi, Sheila

2012-01-01

Objective(s) Extended-spectrum beta-lactamase (ESBL) producing bacteria have an important role in nosocomial infections. Due to the limited availability of information about the molecular epidemiology of ESBL producing bacteria in Mashhad, we decided to investigate about TEM, CTX and SHV ESBLs among urinary Escherichia coli isolates in Mashhad, a city in northeast Iran. Materials and Methods One hundred and eleven clinical isolates of E. coli were diagnosed from hospitalized patients in 2009. After performing antibiogram and phenotypic confirmation test, polymerase chain reaction (PCR) was performed by blaTEM, blaSHV and blaCTX primers and restriction digestion was carried out using PstI and TaqI (Fermentas-Lithuania) for confirmation. Results ESBL producers of E. coli isolates were 33.3%. Among 37 ESBL-producing isolates, 35 (94.6%), 21 (56.8%) and 5 (13.5%) were shown to have blaCTX, blaTEM and blaSHV, genes respectively. Co-resistance to non-beta lactam antibiotics was observed more with ESBL producers (P < 0.05). Conclusion The results showed that the studied ESBL genes are found with high prevalence and among them blaCTX is more widespread in urine E. coli isolates in Mashhad. PMID:23493415

Isolation and characterization of an active mannanase-producing anaerobic bacterium, Clostridium tertium KT-5A, from lotus soil.

PubMed

Kataoka, N; Tokiwa, Y

1998-03-01

Of 10 strains of mannanase-producing anaerobic bacteria isolated from soils and methanogenic sludges, Clostridium tertium KT-5A, which was isolated from lotus soil, produced high amounts of extracellular beta-1,4-mannanase. The isolate was an aerotolerant anaerobe without quinon systems; the cell growth cultivated with no addition of reducing agents was also stable. High yields of mannanase were obtained by inducing enzyme production with galactomannan guar gum and beef extract/peptone as carbon and nitrogen sources, respectively. Fermentation end products on galactomannan fermentation were formate, acetate, lactate, butyrate, carbon dioxide and hydrogen. The extracellular mannanase displayed high activity on galactomannans of locust bean gum galactose/mannose (G/M) ratio 1:4 and spino gum (G/M 1:3), but weak activity on guar gum galactomannan (G/M 1:2) and konjac glucomannan. As far as is known, this is the first report on the isolation of an active mannanase-producing anaerobic bacterium from natural environments.

Enzymatic characterization of clinical and environmental Cryptococcus neoformans strains isolated in Italy.

PubMed

Pini, Gabriella; Faggi, Elisabetta; Campisi, Enza

Cryptococcus neoformans is an encapsulated yeast causing mainly opportunistic infections. The virulence factors involved in cryptococcosis pathogenesis include the presence and the size of the polysaccharide capsule, the production of melanin by phenoloxidase, the growth at 37°C and the enzyme secretion like proteinase, phospholipase and urease. Many other enzymes are secreted by C. neoformans but their role in the fungus virulence is not yet known. In order to investigate this topic, we compared the phospholipase production between strains from patients and from bird droppings, and we examined its relationship to phenoloxidase production. We further characterized the strains by determining the activity of 19 different extracellular enzymes. Two hundred and five Italian C. neoformans clinical isolates and 32 environmental isolates were tested. Phenoloxidase production was determined by the development of brown colonies on Staib's agar. Extracellular phospholipase activity was performed using the semiquantitative egg-yolk plate method. API ZYM commercial kit was used to observe the production and the activity of 19 different extracellular enzymes. Statistical analysis of the results showed a significantly higher phospholipase activity in the clinical isolates than in the environmental isolates. No significant difference about the phenoloxidase production between both groups was found. Regarding the 19 extracellular enzymes tested using the API ZYM commercial kit, acid phosphatase showed the highest enzymatic activity in both groups. Concerning the enzyme α-glucosidase, the clinical isolates presented a significantly higher positivity percentage than the environmental isolates. A hundred percent positivity in the enzyme leucine arylamidase production was observed in both groups, but the clinical isolates metabolized a significantly greater amount of substrate. The higher phospholipase production in the clinical isolates group confirms the possible role of this

Antimicrobial activity of solithromycin against clinical isolates of Legionella pneumophila serogroup 1.

PubMed

Mallegol, Julia; Fernandes, Prabhavathi; Melano, Roberto G; Guyard, Cyril

2014-01-01

The activity of solithromycin was evaluated against clinical Legionella pneumophila serogroup 1 (Lp1) isolates (n = 196) collected in Ontario, Canada, from 1980 to 2011. Its in vitro activity was compared to that of azithromycin (AZM) using the broth microdilution method. Solithromycin had a MIC50 of ≤0.015 μg/ml and a MIC90 of 0.031 μg/ml, making its activity at least 8-fold to 32-fold higher than that of AZM (MIC50 and MIC90, 0.125 μg/ml and 1 μg/ml, respectively). Ninety-nine percent of the isolates had MICs for solithromycin ranging from ≤0.015 μg/ml to 0.031 μg/ml, whereas 83.6% of the isolates showed MICs for AZM ranging from 0.062 μg/ml to 0.25 μg/ml. Interestingly, 96.7% (30 out of 31 clinical isolates) identified with higher AZM MICs (0.5 μg/ml to 2 μg/ml) belonged to the clinically prevalent sequence type 1. To investigate the intracellular activity of solithromycin, in vitro invasion assays were also performed against a subset of representative Lp1 isolates internalized within human lung epithelial cells. Solithromycin and AZM both inhibited growth of all intracellular Lp1 isolates at 1× or 8× MICs, displaying bacteriostatic effects, as would be expected with protein synthesis inhibitor rather than bactericidal activity. Solithromycin demonstrated the highest in vitro and intracellular potency against all Lp1 isolates compared to AZM. Given the rapid spread of resistance mechanisms among respiratory pathogens and the reported treatment failures in legionellosis, the development of this new fluoroketolide, already in phase 3 oral clinical studies, constitutes a promising alternative option for the treatment of legionellosis.

Antimicrobial Activity of Solithromycin against Clinical Isolates of Legionella pneumophila Serogroup 1

PubMed Central

Mallegol, Julia; Fernandes, Prabhavathi

2014-01-01

The activity of solithromycin was evaluated against clinical Legionella pneumophila serogroup 1 (Lp1) isolates (n = 196) collected in Ontario, Canada, from 1980 to 2011. Its in vitro activity was compared to that of azithromycin (AZM) using the broth microdilution method. Solithromycin had a MIC50 of ≤0.015 μg/ml and a MIC90 of 0.031 μg/ml, making its activity at least 8-fold to 32-fold higher than that of AZM (MIC50 and MIC90, 0.125 μg/ml and 1 μg/ml, respectively). Ninety-nine percent of the isolates had MICs for solithromycin ranging from ≤0.015 μg/ml to 0.031 μg/ml, whereas 83.6% of the isolates showed MICs for AZM ranging from 0.062 μg/ml to 0.25 μg/ml. Interestingly, 96.7% (30 out of 31 clinical isolates) identified with higher AZM MICs (0.5 μg/ml to 2 μg/ml) belonged to the clinically prevalent sequence type 1. To investigate the intracellular activity of solithromycin, in vitro invasion assays were also performed against a subset of representative Lp1 isolates internalized within human lung epithelial cells. Solithromycin and AZM both inhibited growth of all intracellular Lp1 isolates at 1× or 8× MICs, displaying bacteriostatic effects, as would be expected with protein synthesis inhibitor rather than bactericidal activity. Solithromycin demonstrated the highest in vitro and intracellular potency against all Lp1 isolates compared to AZM. Given the rapid spread of resistance mechanisms among respiratory pathogens and the reported treatment failures in legionellosis, the development of this new fluoroketolide, already in phase 3 oral clinical studies, constitutes a promising alternative option for the treatment of legionellosis. PMID:24277019

Versatility of Biofilm Matrix Molecules in Staphylococcus epidermidis Clinical Isolates and Importance of Polysaccharide Intercellular Adhesin Expression during High Shear Stress

PubMed Central

Schaeffer, Carolyn R.; Hoang, Tra-My N.; Sudbeck, Craig M.; Alawi, Malik; Tolo, Isaiah E.; Robinson, D. Ashley; Horswill, Alexander R.; Rohde, Holger

2016-01-01

ABSTRACT Staphylococcus epidermidis is a leading cause of hospital-associated infections, including those of intravascular catheters, cerebrospinal fluid shunts, and orthopedic implants. Multiple biofilm matrix molecules with heterogeneous characteristics have been identified, including proteinaceous, polysaccharide, and nucleic acid factors. Two of the best-studied components in S. epidermidis include accumulation-associated protein (Aap) and polysaccharide intercellular adhesin (PIA), produced by the enzymatic products of the icaADBC operon. Biofilm composition varies by strain as well as environmental conditions, and strains producing PIA-mediated biofilms are more robust. Clinically, biofilm-mediated infections occur in a variety of anatomical sites with diverse physiological properties. To test the hypothesis that matrix composition exhibits niche specificity, biofilm-related genetic and physical properties were compared between S. epidermidis strains isolated from high-shear and low-shear environments. Among a collection of 105 clinical strains, significantly more isolates from high-shear environments carried the icaADBC operon than did those from low-shear settings (43.9% versus 22.9%, P < 0.05), while there was no significant difference in the presence of aap (77.2% versus 75.0%, P > 0.05). Additionally, a significantly greater number of high-shear isolates were capable of forming biofilm in vitro in a microtiter assay (82.5% versus 45.8%, P < 0.0001). However, even among high-shear clinical isolates, less than half contained the icaADBC locus; therefore, we selected for ica-negative variants with increased attachment to abiotic surfaces to examine PIA-independent biofilm mechanisms. Sequencing of selected variants identified substitutions capable of enhancing biofilm formation in multiple genes, further highlighting the heterogeneity of S. epidermidis biofilm molecules and mechanisms. IMPORTANCE Staphylococcus epidermidis is a leading cause of

Antimicrobial Susceptibility and Clonality of Clinical Ureaplasma Isolates in the United States

PubMed Central

Fernández, Javier; Karau, Melissa J.; Cunningham, Scott A.; Greenwood-Quaintance, Kerryl E.

2016-01-01

Ureaplasma urealyticum and Ureaplasma parvum are pathogens involved in urogenital tract and intrauterine infections and also in systemic diseases in newborns and immunosuppressed patients. There is limited information on the antimicrobial susceptibility and clonality of these species. In this study, we report the susceptibility of 250 contemporary isolates of Ureaplasma (202 U. parvum and 48 U. urealyticum isolates) recovered at Mayo Clinic, Rochester, MN. MICs of doxycycline, azithromycin, ciprofloxacin, tetracycline, erythromycin, and levofloxacin were determined by broth microdilution, with MICS of the last three interpreted according to CLSI guidelines. Levofloxacin resistance was found in 6.4% and 5.2% of U. parvum and U. urealyticum isolates, respectively, while 27.2% and 68.8% of isolates, respectively, showed ciprofloxacin MICs of ≥4 μg/ml. The resistance mechanism of levofloxacin-resistant isolates was due to mutations in parC, with the Ser83Leu substitution being most frequent, followed by Glu87Lys. No macrolide resistance was found among the 250 isolates studied; a single U. parvum isolate was tetracycline resistant. tet(M) was found in 10 U. parvum isolates, including the single tetracycline-resistant isolate, as well as in 9 isolates which had low tetracycline and doxycycline MICs. Multilocus sequence typing (MLST) performed on a selection of 46 isolates showed high diversity within the clinical Ureaplasma isolates studied, regardless of antimicrobial susceptibility. The present work extends previous knowledge regarding susceptibility to antimicrobial agents, resistance mechanisms, and clonality of Ureaplasma species in the United States. PMID:27246773

FIM-1, a new acquired metallo-β-lactamase from a Pseudomonas aeruginosa clinical isolate from Italy.

PubMed

Pollini, Simona; Maradei, Simona; Pecile, Patrizia; Olivo, Giuseppe; Luzzaro, Francesco; Docquier, Jean-Denis; Rossolini, Gian Maria

2013-01-01

Acquired metallo-β-lactamases (MBLs) are resistance determinants of increasing clinical importance in Gram-negative bacterial pathogens, which confer a broad-spectrum β-lactam resistance, including carbapenems. Several such enzymes have been described since the 1990s. In the present study, a novel acquired MBL, named FIM-1, was identified and characterized. The bla(FIM-1) gene was cloned from a multidrug-resistant Pseudomonas aeruginosa clinical isolate (FI-14/157) cultured from a patient with a vascular graft infection in Florence, Italy. The isolate belonged in the sequence type 235 epidemic clonal lineage. The FIM-1 enzyme is a member of subclass B1 and, among acquired MBLs, exhibited the highest similarity (ca. 40% amino acid identity) with NDM-type enzymes. In P. aeruginosa FI-14/157, the bla(FIM-1) gene was apparently inserted into the chromosome and associated with ISCR19-like elements that were likely involved in the capture and mobilization of this MBL gene. Transfer experiments of the bla(FIM-1) gene to an Escherichia coli strain or another P. aeruginosa strain by conjugation or electrotransformation were not successful. The FIM-1 protein was produced in E. coli and purified by two chromatography steps. Analysis of the kinetic parameters, carried out with the purified enzyme, revealed that FIM-1 has a broad substrate specificity, with a preference for penicillins (except the 6α-methoxy derivative temocillin) and carbapenems. Aztreonam was not hydrolyzed. Detection of this novel type of acquired MBL in a P. aeruginosa clinical isolate underscores the increasing diversity of such enzymes that can be encountered in the clinical setting.

Screening and characterization of extracellular polysaccharides produced by Leuconostoc kimchii isolated from traditional fermented pulque beverage.

PubMed

Torres-Rodríguez, Ingrid; Rodríguez-Alegría, María Elena; Miranda-Molina, Alfonso; Giles-Gómez, Martha; Conca Morales, Rodrigo; López-Munguía, Agustín; Bolívar, Francisco; Escalante, Adelfo

2014-01-01

We report the screening and characterization of EPS produced by LAB identified as Leuconostoc kimchii isolated from pulque, a traditional Mexican fermented, non-distilled alcoholic beverage produced by the fermentation of the sap extracted from several (Agave) maguey species. EPS-producing LAB constitutes an abundant bacterial group relative to total LAB present in sap and during fermentation, however, only two EPS-producing colony phenotypes (EPSA and EPSB, respectively) were detected and isolated concluding that despite the high number of polymer-producing LAB their phenotypic diversity is low. Scanning electron microcopy analysis during EPS-producing conditions revealed that both types of EPS form a uniform porous structure surrounding the bacterial cells. The structural characterization of the soluble and cell-associated EPS fractions of each polymer by enzymatic and acid hydrolysis, as by 1D- and 2D-NMR, showed that polymers produced by the soluble and cell-associated fractions of EPSA strain are dextrans consisting of a linear backbone of linked α-(1→6) Glcp in the main chain with α-(1→2) and α-(1→3)-linked branches. The polymer produced by the soluble fraction of EPSB strain was identified as a class 1 dextran with a linear backbone containing consecutive α-(1→6)-linked D-glucopyranosyl units with few α-(1→3)-linked branches, whereas the cell-associated EPS is a polymer mixture consisting of a levan composed of linear chains of (2→6)-linked β-D-fructofuranosyl residues with β-(2→6) connections, and a class 1 dextran. According to our knowledge this is the first report of dextrans and a levan including their structural characterization produced by L. kimchii isolated from a traditional fermented source.

Evaluation in vitro of the antagonistic substances produced by Lactobacillus spp. isolated from chickens

PubMed Central

Lima, Edna T.; Andreatti Filho, Raphael L.; Okamoto, Adriano S.; Noujaim, José C.; Barros, Mércia R.; Crocci, Adalberto J.

2007-01-01

To determine the inhibitory capacity of lactic acid bacteria due to the action of antagonistic substances, we tested 474 isolates of Lactobacillus from the crop and cecum of chickens against gram-positive and gram-negative indicator microorganisms by the spot-on-the-lawn and well-diffusion antagonism methods. Of the 474 isolates, 265 demonstrated antimicrobial activity against the indicator microorganisms. Isolates identified as L. reuteri, L. salivarius, or Lactobacillus spp. inhibited Enterococcus faecalis, E. faecium, Listeria monocytogenes, and Salmonella spp. but not L. casei, L. delbrueckii, L. fermentum, or L. helveticus by the well-diffusion simultaneous antagonism method under anaerobic incubation conditions. The antagonistic substances produced by some of the Lactobacillus isolates were inactivated after treatment by proteolytic enzymes, which suggested that the substances could be antimicrobial peptides or bacteriocins. PMID:17479773

Population Relationship of Vibrio parahaemolyticus Isolates Derived from Aquaculture Ponds, a Seafood Market, Restaurants, and Clinical Samples.

PubMed

Gao, Lei; Deng, Yi Qin; Chen, Chang; Ke, Chang Wen; Li, Bo Sheng; Long, Yun Ying; Liu, Zhu Hong; Wei, Lu

2016-06-01

To study the relationship between environmental and clinical populations of Vibrio parahaemolyticus, we collected in total 86 isolates from Southern China during one and a half years. Sixty-eight isolates were recovered from aquaculture ponds, a seafood market, and restaurants, and 18 isolates were recovered from clinical samples. Virulence gene analysis revealed that 25 isolates (14 clinical and 11 environmental) tested positive for tdh, but only 4 carried trh. Interestingly, none of the tdh(+) environmental isolates was recovered from ponds. Both environmental and clinical tdh(+) isolates, except for one clinical isolate, harbor type III secretion system 2α (T3SS2α) and T3SS2β-related genes, including vopB2α, which was previously suggested to be absent from environmental strains. More than 70% of clinical isolates carried the pandemic marker of new toxRS (GS-PCR(+)), which was not present in the environmental isolates. Pulsed-field gel electrophoresis and multilocus sequence typing analysis showed a high degree of genetic diversity within the environmental isolates. In contrast, the clinical population formed a tight cluster that differed from the environmental isolates. These findings suggest that the pandemic strains of V. parahaemolyticus may not directly originate from marine animals. Rather the environments where they are maintained could serve as reservoirs for toxigenic, but not pandemic strains. These environments provide an ideal place for generation of new toxigenic strains through DNA exchange, which was revealed by extensive recombination events in recA sequences of the environmental isolates.

Molecular and biochemical characterization of Iranian surfactin-producing Bacillus subtilis isolates and evaluation of their biocontrol potential against Aspergillus flavus and Colletotrichum gloeosporioides.

PubMed

Mohammadipour, Matin; Mousivand, Maryam; Salehi Jouzani, Gholamreza; Abbasalizadeh, Saeed

2009-04-01

The characterization of surfactin-producing Bacillus subtilis isolates collected from different ecological zones of Iran is presented. Characterization was performed using blood agar, PCR, drop-collapse, and reverse-phase high-performance liquid chromatography (HPLC) analyses, and the isolates' biocontrol effects against the aflatoxin-producing agent Aspergillus flavus and the citrus antracnosis agent Colletotrichum gloeosporioides were studied. In total, 290 B. subtilis isolates were isolated from phylosphere and rhizosphere samples collected from fields and gardens of 5 provinces of Iran. Blood agar assays showed that 185 isolates produced different biosurfactants. Isolates containing the sfp gene, coding for surfactin, were detected using the PCR method. It was found that 14 different isolates contained the sfp gene. Drop-collapse assays, which detect isolates with high production of surfactin, showed that 7 isolates produced high levels of surfactin. It was found from HPLC analysis that the isolates containin the sfp gene produced between 55 and 1610 mg of surfactin per litre of broth medium. Four isolates, named BS119m, BS116l, N3dn, and BS113c, produced more than 1000 mg of surfactin per litre of broth. The highest surfactin production level was observed for isolate BS119m (1610 mg/L). The antagonistic potential of the sfp gene-containing isolates was determined using dual culture and chloroform vapour methods. Our bioassay results indicated that isolate BS119m showed high inhibitory effects against A. flavus (100%) and C. gloeosporioides (88%). Furthermore, the effect of purified surfactin on the growth of A. flavus was evaluated. Mycelia growth was considerably reduced with increasing concentration of surfactin, and 36%, 54%, 84%, and 100% inhibitions of mycelia growth were, respectively, observed at 20, 40, 80, and 160 mg/L after 7 days of incubation.

Molecular characterization of multidrug-resistant extended-spectrum β-lactamase-producing Enterobacteriaceae isolated in Antananarivo, Madagascar

PubMed Central

2013-01-01

Background We investigated the molecular characteristics of multidrug-resistant, extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae isolated in community settings and in hospitals in Antananarivo, Madagascar. Results Forty-nine E. coli, K. pneumoniae, K. oxytoca and E. cloacae ESBL-producing isolates were studied. In antimicrobial susceptibility analyses, many of the isolates exhibited resistance to aminoglycosides, fluoroquinolones and trimethoprim-sulfamethoxazole. Gene amplification analysis and sequencing revealed that 75.5% (n=37) of the isolates harbored blaCTX-M-15 and 38.7% (n=19) harbored blaSHV-12. The non-ESBLs resistance genes detected were blaTEM-1, blaOXA-1, aac(6′)-Ib,aac(6′)-Ib-cr, tetA, sul-1, sul-2, qnrA, qnrB and catB-3. We found dfrA and aadA gene cassettes in the class 1 integron variable regions of the isolates, and the combination of dfrA17-aadA5 to be the most prevalent. All blaCTX-M-15 positive isolates also contained the ISEcp1 insertion element. Conjugation and transformation experiments indicated that 70.3% of the antibiotic resistance genes resided on plasmids. Through a PCR based replicon typing method, plasmids carrying the blaSHV-12 or blaCTX-M-15 genes were assigned to either the IncFII replicon type or, rarely, to the HI2 replicon type. All isolates were subtyped by the rep-PCR and ERIC-PCR methods. Phylogenetic grouping and virulence genotyping of the E. coli isolates revealed that most of them belonged to group A1. One isolate assigned to group B2 harbored blaCTX-M-15 and five virulence genes (traT, fyuA, iutA, iha and sfa) and was related to the O25b-ST131 clone. Conclusions Our results highlight the dissemination of multidrug resistant Enterobacteriaceae isolates in Antananarivo. These findings underline the need for a rational use of antibiotic and for appropriate methods of screening ESBL in routine laboratories in Antananarivo. PMID:23594374

Phenotypic and genotypic characterization of biofilm formation among Staphylococcus aureus isolates from clinical specimens, an Atomic Force Microscopic (AFM) study.

PubMed

Bazari, Pelin Aslani Menareh; Honarmand Jahromy, Sahar; Zare Karizi, Shohreh

2017-09-01

Staphylococcus aureus is a major cause of nosocomial infections. Biofilm formation is an important factor for bacterial pathogenesis. Its mechanisms are complex and include of many genes depends on expression of icaADBC operon involved in the synthesis of a polysaccharide intercellular adhesion. The aim of study was to investigate biofilm forming ability of Staphylococcus aureus strains by phenotypic and genotypic methods. Also Atomic Force microscope (AFM) was used to visualize biofilm formation. 140 Isolates were collected from clinical specimens of patients in Milad Hospital, Tehran and diagnosed by biochemical tests. The ability of strains to produce slime was evaluated by CRA method. For diagnosing of bacterial EPS, Indian ink staining were used and finally biofilm surface of 3 isolates observed by AFM. The prevalence of icaA and icaD genes was determined by PCR. By CRA method 15% of samples considered as positive slime producers, 44.28% as intermediate and 40.71% indicative as negative slime producers. 118 staphylococcus aureus strains showed a distinct halo transparent zone but 22 strains showed no halo zone. AFM analysis of Slime positive isolates showed a distinct and complete biofilm formation. In slime negative strain, there was not observed biofilm. The prevalence of icaA, icaD genes was 44.2% and 10% of the isolates had both genes simultaneously. There is a relationship between exopolysaccharide layer and biofilm formation of Staphylococcus aureus isolates. The presence of icaAD genes among isolates is not associated with in vitro formation of biofilm. AFM is a useful tool for observation of bacterial biofilm formation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Characterisation of clinically isolated Streptococcus pyogenes from balanoposthitis patients, with special emphasis on emm89 isolates.

PubMed

Hasegawa, Tadao; Hata, Nanako; Matsui, Hideyuki; Isaka, Masanori; Tatsuno, Ichiro

2017-04-01

Streptococcus pyogenes causes a variety of diseases, such as pharyngitis and toxic shock syndrome. In addition, this bacterium is a causative agent of balanoposthitis. To reveal the bacteriological characteristics of the isolates from balanoposthitis patients, we analysed 47 isolates. In addition, novel clade genotype emm89 S. pyogenes isolates have been reported to be spreading worldwide recently. Hence, we further analysed eight emm89 isolates. A drug susceptibility experiment was performed and emm types were determined. More detailed experiments, such as PCR analysis for the presence of virulence-associated genes and MLST analysis, were performed especially using emm89 isolates. All isolates were sensitive to ampicillin, but 34 % of the isolates were resistant to at least one antibiotic. The emm types of the isolates varied, with emm89 and emm11 being the most prevalent, but the emm1 type was not detected. The analysis of emm89 isolates revealed that drug susceptibilities varied. All isolates were negative for the hasABC gene and produced active NADase that are characteristics of novel clade genotype emm89 S. pyogenes. MLST analysis demonstrated that six isolates were of the ST101 type, the most predominant type reported thus far, but two isolates were of the ST646 type. According to the PCR analysis used to determine the presence of streptococcal pyrogenic exotoxin-related genes, the six ST101 isolates were further classified into four groups. These results suggest that balanoposthitis is caused by a variety of types of S. pyogenes, with novel clade genotype emm89 isolates playing a role in balanoposthitis infections in Japan.

The anti-candidal activity of Satureja khuzistanica ethanol extract against clinical isolates of C. albicans.

PubMed

Mahboubi, M; Kazempour, N

2016-03-01

Candida albicans is the common cause of some infectious diseases such as vaginal candidiasis or candidemia. Due to the emergence of drug resistant isolates of C. albicans, finding a new anti-Candida agent is a new strategy for current treatments. This study evaluated the anti-candidal activity of Satureja khuzistanica ethanol extract against clinical isolates of C. albicans. S. khuzistanica ethanol extract from aerial parts of plant at full flowering stage was evaluated against 30 clinical isolates and two ATCC reference strains of C. albicans by disc diffusion and micro-broth dilution assay. Also, in this study we evaluated the synergistic effects of amphotericin B, clotrimazole and ketoconazole with S. khuzistanica ethanol extract. The means of MIC and MFC of S. khuzistanica ethanol extract against clinical isolates were 299.4 and 722.6 (μg/mL), respectively. S. khuzistanica ethanol extract increased the anti-candidal effect of amphotericin B and ketoconazole, while it had no synergistic effect on clotrimazole against clinical isolates of C. albicans. Therefore, S. khuzistanica ethanol extract can be introduced as a new source of anti-candidal agent against clinical isolates of C. albicans. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Isolation and characterization of bacteriophages specific to hydrogen-sulfide-producing bacteria.

PubMed

Gong, Chao; Heringa, Spencer; Singh, Randhir; Kim, Jinkyung; Jiang, Xiuping

2013-01-01

The objectives of this study were to isolate and characterize bacteriophages specific to hydrogen-sulfide-producing bacteria (SPB) from raw animal materials, and to develop a SPB-specific bacteriophage cocktail for rendering application. Meat, chicken offal, and feather samples collected from local supermarkets and rendering processing plants were used to isolate SPB (n = 142). Bacteriophages (n = 52) specific to SPB were isolated and purified from the above samples using 18 of those isolated SPB strains as hosts. The host ranges of bacteriophages against 5 selected SPB strains (Escherichia coli, Citrobacter freundii, and Hafnia alvei) were determined. Electron microscopy observation of 9 phages selected for the phage cocktail revealed that 6 phages belonged to the family of Siphoviridae and 3 belonged to the Myoviridae family. Restriction enzyme digestion analysis with endonuclease DraI detected 6 distinguished patterns among the 9 phages. Phage treatment prevented the growth of SPB for up to 10 h with multiplicity of infection ratios of 1, 10, 100, and 1000 in tryptic soy broth at 30 °C, and extended the lag phase of SPB growth for 2 h at 22 °C with multiplicities of infection of 10, 100, and 1000. These results suggest that the selected bacteriophage cocktail has a high potential for phage application to control SPB in raw animal materials destined for the rendering process.

Complete genome sequence of the clinical Campylobacter coli isolate 15-537360

USDA-ARS?s Scientific Manuscript database

Campylobacter coli strain 15-537360 was originally isolated from a 42 year-old patient with gastroenteritis. Here we report its complete genome sequence, which comprises a 1.7 Mbp chromosome and a 29 kbp conjugative cryptic plasmid. This is the first complete genome sequence of a clinical isolate of...

Macromolecular and solution properties of Cepacian: the exopolysaccharide produced by a strain of Burkholderia cepacia isolated from a cystic fibrosis patient.

PubMed

Sist, Paola; Cescutti, Paola; Skerlavaj, Silvia; Urbani, Ranieri; Leitão, Jorge H; Sá-Correia, Isabel; Rizzo, Roberto

2003-09-01

Light scattering and viscosity measurements were carried out on the previously chemically characterised exopolysaccharide produced by a strain of Burkholderia cepacia isolated from a cystic fibrosis patient. The same exopolysaccharide was also produced by other clinical strains in different laboratories. Therefore, the name Cepacian is now proposed for this exopolysaccharide. Experiments performed as a function of the ionic strength on the native polymer revealed a change in the overall shape of the polymer at low ionic strength. This behaviour was absent in the de-acetylated sample. Potentiometric titrations and light scattering experiments carried out on the acidic form of the native polymer revealed the formation of macromolecular aggregates with a stoichiometry n and 2n stabilised by interactions involving the uronic acid residues.

Hypocrea lixii, novel endophytic fungi producing anticancer agent cajanol, isolated from pigeon pea (Cajanus cajan [L.] Millsp.).

PubMed

Zhao, J; Li, C; Wang, W; Zhao, C; Luo, M; Mu, F; Fu, Y; Zu, Y; Yao, M

2013-07-01

The aim was to isolate, identify and characterize endophytes from pigeon pea (Cajanus cajan [L.] Millsp.), as novel producer of cajanol and its in vitro cytotoxicity assay. Isolation, identification and characterization of novel endophytes producing cajanol from the roots of pigeon pea were investigated. The endophytes were identified as Hypocrea lixii by morphological and molecular methods. Cajanol produced by endophytes were quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). R-18 produced the highest levels of cajanol (322·4 ± 10·6 μg l(-1) or 102·8 ± 6·9 μg g(-1) dry weight of mycelium) after incubation for 7 days. The cytotoxicity towards human lung carcinoma cells (A549) of fungal cajanol was investigated in vitro. First, a novel endophyte Hypocrea lixii, producing anticancer agent cajanol, was isolated from the host pigeon pea (Cajanus cajan [L.] Millsp.). Fungal cajanol possessed stronger cytotoxicity activity towards A549 cells in time- and dose-dependent manners. This endophyte is a potential handle for scientific and commercial exploitation, and it could provide a promising alterative approach for large-scale production of cajanol to satisfy new anticancer drug development. Journal of Applied Microbiology © 2013 The Society for Applied Microbiology.

Genetic Relatedness and Novel Sequence Types of Non-O157 Shiga Toxin-Producing Escherichia coli Strains Isolated in Argentina.

PubMed

Cadona, Jimena S; Bustamante, Ana V; González, Juliana; Sanso, A Mariel

2016-01-01

Shiga toxin-producing Escherichia coli (STEC) is a foodborne pathogen responsible for severe disease in humans such as hemolytic uremic syndrome (HUS) and cattle, the principal reservoir. Identification of the clones/lineages is important as several characteristics, among them propensity to cause disease varies with STEC phylogenetic origin. At present, we do not know what STEC clones, especially of non-O157:H7, are circulating in Argentina. To fill this knowledge gap we assessed the genetic diversity of STEC strains isolated in Argentina from various sources, mostly cattle and food, using multilocus sequence typing (MLST). Our objectives were to determine the phylogenetic relationships among strains and to compare them with strains from different geographic origins, especially with those from clinical human cases, in order to evaluate their potential health risk. A total of 59 STEC isolates from 41 serotypes were characterized by MLST. Analysis using EcMLST database identified 38 sequence types (ST), 17 (45%) of which were new STs detected in 18 serotypes. Fifteen out of 38 STs identified were grouped into 11 clonal groups (CGs) and, 23 not grouped in any of the defined CGs. Different STs were found in the same serotype. Results highlighted a high degree of phylogenetic heterogeneity among Argentinean strains and they showed that several cattle and food isolates belonged to the same STs that are commonly associated with clinical human cases in several geographical areas. STEC is a significant public health concern. Argentina has the highest incidence of HUS in the world and this study provides the first data about which STEC clones are circulating. Data showed that most of them might pose a serious zoonotic risk and this information is important for developing public health initiatives. However, the actual potential risk will be defined by the virulence profiles, which may differ among isolates belonging to the same ST.

Antimicrobial Susceptibility and Clonality of Clinical Ureaplasma Isolates in the United States.

PubMed

Fernández, Javier; Karau, Melissa J; Cunningham, Scott A; Greenwood-Quaintance, Kerryl E; Patel, Robin

2016-08-01

Ureaplasma urealyticum and Ureaplasma parvum are pathogens involved in urogenital tract and intrauterine infections and also in systemic diseases in newborns and immunosuppressed patients. There is limited information on the antimicrobial susceptibility and clonality of these species. In this study, we report the susceptibility of 250 contemporary isolates of Ureaplasma (202 U. parvum and 48 U. urealyticum isolates) recovered at Mayo Clinic, Rochester, MN. MICs of doxycycline, azithromycin, ciprofloxacin, tetracycline, erythromycin, and levofloxacin were determined by broth microdilution, with MICS of the last three interpreted according to CLSI guidelines. Levofloxacin resistance was found in 6.4% and 5.2% of U. parvum and U. urealyticum isolates, respectively, while 27.2% and 68.8% of isolates, respectively, showed ciprofloxacin MICs of ≥4 μg/ml. The resistance mechanism of levofloxacin-resistant isolates was due to mutations in parC, with the Ser83Leu substitution being most frequent, followed by Glu87Lys. No macrolide resistance was found among the 250 isolates studied; a single U. parvum isolate was tetracycline resistant. tet(M) was found in 10 U. parvum isolates, including the single tetracycline-resistant isolate, as well as in 9 isolates which had low tetracycline and doxycycline MICs. Multilocus sequence typing (MLST) performed on a selection of 46 isolates showed high diversity within the clinical Ureaplasma isolates studied, regardless of antimicrobial susceptibility. The present work extends previous knowledge regarding susceptibility to antimicrobial agents, resistance mechanisms, and clonality of Ureaplasma species in the United States. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Improving safety of salami by application of bacteriocins produced by an autochthonous Lactobacillus curvatus isolate.

PubMed

de Souza Barbosa, Matheus; Todorov, Svetoslav Dimitrov; Ivanova, Iskra; Chobert, Jean-Marc; Haertlé, Thomas; de Melo Franco, Bernadette Dora Gombossy

2015-04-01

The aims of this study were to isolate LAB with anti-Listeria activity from salami samples, characterize the bacteriocin/s produced by selected isolates, semi-purify them and evaluate their effectiveness for the control of Listeria monocytogenes during manufacturing of salami in a pilot scale. Two isolates (differentiated by RAPD-PCR) presented activity against 22 out of 23 L. monocytogenes strains for bacteriocin MBSa2, while the bacteriocin MBSa3 inhibited all 23 strains in addition to several other Gram-positive bacteria for both antimicrobials and were identified as Lactobacillus curvatus based on 16S rRNA sequencing. A three-step purification procedure indicated that both strains produced the same two active peptides (4457.9 Da and 4360.1 Da), homlogous to sakacins P and X, respectively. Addition of the semi-purified bacteriocins produced by Lb. curvatus MBSa2 to the batter for production of salami, experimentally contaminated with L. monocytogenes (10(4)-10(5) CFU/g), caused 2 log and 1.5 log reductions in the counts of the pathogen in the product after 10 and 20 days respectively, highlighting the interest for application of these bacteriocins to improve safety of salami during its manufacture. Copyright © 2014 Elsevier Ltd. All rights reserved.

An investigation of exudative epidermitis (greasy pig disease) and antimicrobial resistance patterns of Staphylococcus hyicus and Staphylococcus aureus isolated from clinical cases

PubMed Central

Park, Jeonghwa; Friendship, Robert M.; Poljak, Zvonimir; Weese, J. Scott; Dewey, Cate E.

2013-01-01

Exudative epidermitis (EE) is a common skin disease of young pigs, caused mainly by Staphylococcus hyicus. Increased prevalence of EE and poor response to treatment are reported. Common strategies used by Ontario pork producers to treat pigs with EE were determined using a survey. Injection of penicillin G was reported as the most common parenteral antibiotic choice. Antimicrobial resistance patterns of S. hyicus and Staphylococcus aureus isolated from clinical cases (30 herds with samples from approximately 6 pigs per farm) showed that 97% of S. hyicus isolates were resistant to penicillin G and ampicillin; 71% of these isolates were resistant to ceftiofur. Similar resistance was noted among S. aureus isolates. Antimicrobial resistance has become a problem in the treatment of EE in Ontario. PMID:23904636

Metallo-Beta-Lactamase Producing Pseudomonas aeruginosa in a Healthcare Setting in Alexandria, Egypt.

PubMed

Abaza, Amani F; El Shazly, Soraya A; Selim, Heba S A; Aly, Gehan S A

2017-09-27

Pseudomonas aeruginosa has emerged as a major healthcare associated pathogen that creates a serious public health disaster in both developing and developed countries. In this work we aimed at studying the occurrence of metallo-beta-lactamase (MBL) producing P. aeruginosa in a healthcare setting in Alexandria, Egypt. This cross sectional study included 1583 clinical samples that were collected from patients admitted to Alexandria University Students' Hospital. P. aeruginosa isolates were identified using standard microbiological methods and were tested for their antimicrobial susceptibility patterns using single disc diffusion method according to the Clinical and Laboratory Standards Institute recommendations. Thirty P. aeruginosa isolates were randomly selected and tested for their MBL production by both phenotypic and genotypic methods. Diagnostic Epsilometer test was done to detect metallo-beta-lactamase enzyme producers and polymerase chain reaction test was done to detect imipenemase (IMP), Verona integron-encoded (VIM) and Sao Paulo metallo-beta-lactamase (IMP) encoding genes. Of the 1583 clinical samples, 175 (11.3%) P. aeruginosa isolates were identified. All the 30 (100%) selected P. aeruginosa isolates that were tested for MBL production by Epsilometer test were found to be positive; where 19 (63.3%) revealed blaSPM gene and 11 (36.7%) had blaIMP gene. blaVIM gene was not detected in any of the tested isolates. Isolates of MBL producing P. aeruginosa were highly susceptible to polymyxin B 26 (86.7%) and highly resistant to amikacin 26 (86.7%). MBL producers were detected phenotypically by Epsilometer test in both carbapenem susceptible and resistant P. aeruginosa isolates. blaSPM was the most commonly detected MBL gene in P. aeruginosa isolates.

In Vitro Activity of Aztreonam-Avibactam against Enterobacteriaceae and Pseudomonas aeruginosa Isolated by Clinical Laboratories in 40 Countries from 2012 to 2015.

PubMed

Karlowsky, James A; Kazmierczak, Krystyna M; de Jonge, Boudewijn L M; Hackel, Meredith A; Sahm, Daniel F; Bradford, Patricia A

2017-09-01

The combination of the monobactam aztreonam and the non-β-lactam β-lactamase inhibitor avibactam is currently in clinical development for the treatment of serious infections caused by metallo-β-lactamase (MBL)-producing Enterobacteriaceae , a difficult-to-treat subtype of carbapenem-resistant Enterobacteriaceae for which therapeutic options are currently very limited. The present study tested clinically significant isolates of Enterobacteriaceae ( n = 51,352) and Pseudomonas aeruginosa ( n = 11,842) collected from hospitalized patients in 208 medical center laboratories from 40 countries from 2012 to 2015 for in vitro susceptibility to aztreonam-avibactam, aztreonam, and comparator antimicrobial agents using a standard broth microdilution methodology. Avibactam was tested at a fixed concentration of 4 μg/ml in combination with 2-fold dilutions of aztreonam. The MIC 90 s of aztreonam-avibactam and aztreonam were 0.12 and 64 μg/ml, respectively, for all Enterobacteriaceae isolates; >99.9% of all isolates and 99.8% of meropenem-nonsusceptible isolates ( n = 1,498) were inhibited by aztreonam-avibactam at a concentration of ≤8 μg/ml. PCR and DNA sequencing identified 267 Enterobacteriaceae isolates positive for MBL genes (NDM, VIM, IMP); all Enterobacteriaceae carrying MBLs demonstrated aztreonam-avibactam MICs of ≤8 μg/ml and a MIC 90 of 1 μg/ml. Against all P. aeruginosa isolates tested, the MIC 90 of both aztreonam-avibactam and aztreonam was 32 μg/ml; against MBL-positive P. aeruginosa isolates ( n = 452), MIC 90 values for aztreonam-avibactam and aztreonam were 32 and 64 μg/ml, respectively. The current study demonstrated that aztreonam-avibactam possesses potent in vitro activity against a recent, sizeable global collection of Enterobacteriaceae clinical isolates, including isolates that were meropenem nonsusceptible, and against MBL-positive isolates of Enterobacteriaceae , for which there are few treatment options. Copyright © 2017 American

In Vitro Activity of Aztreonam-Avibactam against Enterobacteriaceae and Pseudomonas aeruginosa Isolated by Clinical Laboratories in 40 Countries from 2012 to 2015

PubMed Central

Karlowsky, James A.; de Jonge, Boudewijn L. M.; Hackel, Meredith A.; Sahm, Daniel F.

2017-01-01

ABSTRACT The combination of the monobactam aztreonam and the non-β-lactam β-lactamase inhibitor avibactam is currently in clinical development for the treatment of serious infections caused by metallo-β-lactamase (MBL)-producing Enterobacteriaceae, a difficult-to-treat subtype of carbapenem-resistant Enterobacteriaceae for which therapeutic options are currently very limited. The present study tested clinically significant isolates of Enterobacteriaceae (n = 51,352) and Pseudomonas aeruginosa (n = 11,842) collected from hospitalized patients in 208 medical center laboratories from 40 countries from 2012 to 2015 for in vitro susceptibility to aztreonam-avibactam, aztreonam, and comparator antimicrobial agents using a standard broth microdilution methodology. Avibactam was tested at a fixed concentration of 4 μg/ml in combination with 2-fold dilutions of aztreonam. The MIC90s of aztreonam-avibactam and aztreonam were 0.12 and 64 μg/ml, respectively, for all Enterobacteriaceae isolates; >99.9% of all isolates and 99.8% of meropenem-nonsusceptible isolates (n = 1,498) were inhibited by aztreonam-avibactam at a concentration of ≤8 μg/ml. PCR and DNA sequencing identified 267 Enterobacteriaceae isolates positive for MBL genes (NDM, VIM, IMP); all Enterobacteriaceae carrying MBLs demonstrated aztreonam-avibactam MICs of ≤8 μg/ml and a MIC90 of 1 μg/ml. Against all P. aeruginosa isolates tested, the MIC90 of both aztreonam-avibactam and aztreonam was 32 μg/ml; against MBL-positive P. aeruginosa isolates (n = 452), MIC90 values for aztreonam-avibactam and aztreonam were 32 and 64 μg/ml, respectively. The current study demonstrated that aztreonam-avibactam possesses potent in vitro activity against a recent, sizeable global collection of Enterobacteriaceae clinical isolates, including isolates that were meropenem nonsusceptible, and against MBL-positive isolates of Enterobacteriaceae, for which there are few treatment options. PMID:28630192

Isolation and molecular characterization of Salmonella enterica serovar Enteritidis from poultry house and clinical samples during 2010.

PubMed

Mezal, Ezat H; Sabol, Ashley; Khan, Mariam A; Ali, Nawab; Stefanova, Rossina; Khan, Ashraf A

2014-04-01

A total of 60 Salmonella enterica serovar (ser.) Enteritidis isolates, 28 from poultry houses and 32 from clinical samples, were isolated during 2010. These isolates were subjected to testing and analyzed for antibiotic resistance, virulence genes, plasmids and plasmid replicon types. To assess genetic diversity, pulsed-field gel electrophoresis (PFGE) fingerprinting, using the XbaI restriction enzyme, Multiple-Locus Variable-Number Tandem Repeat Analysis (MLVA) and plasmid profiles were performed. All isolates from poultry, and 10 out of 32 clinical isolates were sensitive to ampicillin, chloramphenicol, gentamicin, kanamycin, nalidixic acid, sulfisoxazole, streptomycin, and tetracycline. Twenty-one of thirty-two clinical isolates were resistant to ampicillin and tetracycline, and one isolate was resistant to nalidixic acid. PFGE typing of sixty ser. Enteritidis isolates by XbaI resulted in 10-12 bands and grouped into six clusters each with similarity from 95% to 81%. The MLVA analysis of sixty isolates gave 18 allele profiles with the majority of isolates displayed in three groups, and two clinical isolates found to be new in the PulseNet national MLVA database. All isolates were positive for 12 or more of the 17 virulence genes mostly found in S. enterica (spvB, spiA, pagC, msgA, invA, sipB, prgH, spaN, orgA, tolC, iroN, sitC, IpfC, sifA, sopB, and pefA) and negative for one gene (cdtB). All isolates carried a typical 58 kb plasmid, type Inc/FIIA. Three poultry isolates and one clinical isolate carried small plasmids with 3.8, 6, 7.6 and 11.5 kb. Ten of the clinical isolates carried plasmids, with sizes 36 and 38 kb, types IncL/M and IncN, and one isolate carried an 81 kb plasmid, type IncI. Southern hybridization of a plasmid with an Inc/FIIA gene probe hybridized one large 58 kb plasmid in all isolates. Several large and small plasmids from poultry isolates were not typed by our PCR-based method. These results confirmed that PFGE fingerprinting has

Wedge-shaped microfluidic chip for circulating tumor cells isolation and its clinical significance in gastric cancer.

PubMed

Yang, Chaogang; Zhang, Nangang; Wang, Shuyi; Shi, Dongdong; Zhang, Chunxiao; Liu, Kan; Xiong, Bin

2018-05-23

Circulating tumor cells (CTCs) have great potential in both basic research and clinical application for the managements of cancer. However, the complicated fabrication processes and expensive materials of the existing CTCs isolation devices, to a large extent, limit their clinical translation and CTCs' clinical value. Therefore, it remains to be urgently needed to develop a new platform for achieving CTCs detection with low-cost, mass-producible but high performance. In the present study, we introduced a novel wedge-shaped microfluidic chip (named CTC-ΔChip) fabricated by two pieces of glass through wet etching and thermal bonding technique for CTCs isolation, which achieved CTCs enrichment by different size without cell surface expression markers and CTCs identification with three-color immunocytochemistry method (CK+/CD45-/Nucleus+). We validated the feasibility of CTC-ΔChip for detecting CTCs from different types of solid tumor. Furthermore, we applied the newly-developed platform to investigate the clinical significance of CTCs in gastric cancer (GC). Based on "label-free" characteristic, the capture efficiency of CTC-ΔChip can be as high as 93.7 ± 3.2% in DMEM and 91.0 ± 3.0% in whole blood sample under optimized conditions. Clinically, CTC-ΔChip exhibited the feasibility of detecting CTCs from different types of solid tumor, and it identified 7.30 ± 7.29 CTCs from 2 mL peripheral blood with a positive rate of 75% (30/40) in GC patients. Interestingly, we found that GC CTCs count was significantly correlated with multiple systemic inflammation indexes, including the lymphocyte count, platelet count, the level of neutrophil to lymphocyte ratio and platelet to lymphocyte ratio. In addition, we also found that both the positivity rate and CTCs count were significantly associated with multiple clinicopathology parameters. Our novel CTC-ΔChip shows high performance for detecting CTCs from less volume of blood samples of cancer patients and

Rapid Identification of Vancomycin Resistant Enterococcus Faecalis Clinical Isolates using a Sugar Fermentation Method

PubMed Central

Raeisi, Javad; Saifi, Mahnaz; Pourshafie, Mohammad Reza; Habibi, Mehri; Mohajerani, Hamid Reza; Akbari, Neda

2017-01-01

Introduction Vancomycin Resistant Enterococci (VRE) can be found all over the world. Thus, rapid detection of the isolates could be of high importance in the treatment or prevention of the associated disease. Aim To measure the turanose fermentation in Enterococcus faecalis clinical isolates for rapid differentiation of VRE and Vancomycin-Susceptible E. faecalis (VSE) isolates. Materials and Methods Forty E. faecalis samples were isolated from 200 clinical samples in Tehran Medical Center, Iran, from October 2012 to December 2012. These isolates were detected according to the standard microbial and biochemical tests. Detection of VRE isolates was originally performed by disk diffusion using 1 μg vancomycin disk, followed by Polymerase Chain Reaction (PCR) amplification of the vanA gene. Finally, the turanose consumption in 1%, 0.7% and 0.5% dilutions was detected by a phenotypic method. Results Among the 40 E. faecalis isolates, 20 vancomycin-susceptible and 20 vancomycin-resistant E. faecalis were isolated according to the disk diffusion and PCR of the vanA gene. There was a considerable difference between VRE and VSE isolates in 0.7% dilution of turanose. However, there was no significant difference between VRE and VSE in 1% and 0.5% dilutions of turanose. Conclusion Since detection of VRE isolates is of high importance, especially in nosocomial infections, phenotypic methods may be highly useful for this purpose. In conclusion, our data indicate that VRE isolated from clinical samples could be distinguished from VSE isolates by turanose fermentation at dilution 0.7%. PMID:28511382

A novel functional class 2 integron in clinical Proteus mirabilis isolates.

PubMed

Wei, Quhao; Hu, Qingfeng; Li, Shanshan; Lu, Huoyang; Chen, Guoqiang; Shen, Beiqiong; Zhang, Ping; Zhou, Yonglie

2014-04-01

To describe a novel functional class 2 integron that was found in clinical Proteus mirabilis isolates. Class 1 and 2 integrons were screened by PCR in 153 clinical Proteus isolates. The variable regions of class 1 and 2 integrons were determined by restriction analysis and sequencing. The mutations of internal stop codons in class 2 integrons and their common promoters were also determined by sequencing. Enterobacterial repetitive intergenic consensus (ERIC)-PCR was used to analyse the phylogenetic relations of class 2 integron-positive P. mirabilis isolates. Class 1 integrons were detected in 96 (63%) of 153 Proteus isolates: eight different gene cassette arrays were detected, including dfrA32-ereA1-aadA2, which was detected for the first time in P. mirabilis. Class 2 integrons were detected in 101 (66%) of 153 Proteus isolates: four different gene cassette arrays were detected, including dfrA1-catB2-sat2-aadA1, which was detected for the first time in a class 2 integron. A novel functional class 2 integron was detected in 38 P. mirabilis isolates with a common promoter (-35 TTTAAT|16 bp|-10 TAAAGT). The variable region of this functional class 2 integron contained dfrA14 and three novel open reading frames with unknown functions. Very similar ERIC-PCR fingerprinting patterns were detected in these 38 P. mirabilis isolates and were different from other class 2 integron-positive isolates. A novel functional class 2 integron was found for the first time in P. mirabilis. These functional class 2 integron-harbouring P. mirabilis isolates were likely to be clonally spread in our hospital.

Safety Evaluation of Enterocin Producer Enterococcus sp. Strains Isolated from Traditional Turkish Cheeses.

PubMed

Avcı, Mine; Özden Tuncer, Banu

2017-07-06

The purpose of this study was to determine the antimicrobial activity and occurrence of bacteriocin structural genes in Enterococcus spp. isolated from different cheeses and also investigate some of their virulence factors. Enterococcus strains were isolated from 33 different cheeses. Enterococcus faecium (6 strains) and Enterococcus faecalis (5 strains) enterocin-producing strains were identified by 16S rDNA analyses. Structural genes entA, entB, entP and entX were detected in some isolates. Multiple enterocin structural genes were found in 7 strains. None of the tested enterococci demonstrated anyβ-haemolytic activity and only one strain had gelatinase activity. Six strains showed multiple antibiotic resistance patterns and in addition, vanA and several virulence genes were detected in many strains. Only E. faecalis MBE1-9 showed tyrosine decarboxylase activity and tdc gene was detected only in this strain.

Genomic investigation of Staphylococcus aureus isolates from bulk tank milk and dairy cows with clinical mastitis.

PubMed

Ronco, Troels; Klaas, Ilka C; Stegger, Marc; Svennesen, Line; Astrup, Lærke B; Farre, Michael; Pedersen, Karl

2018-02-01

Staphylococcus aureus is one of the most common pathogens that cause mastitis in dairy cows. Various subtypes, virulence genes and mobile genetic elements have been associated with isolates from bulk tank milk and clinical mastitis. So far, no Danish cattle associated S. aureus isolates have been whole-genome sequenced and further analyzed. Thus, the main objective was to investigate the population structure and genomic content of isolates from bulk tank milk and clinical mastitis, using whole-genome sequencing. This may reveal the origin of strains that cause clinical mastitis. S. aureus isolates from bulk tank milk (n = 94) and clinical mastitis (n = 63) were collected from 91 and 24 different farms, respectively and whole-genome sequenced. The genomic content was analyzed and a phylogenetic tree based on single nucleotide polymorphisms was constructed. In general, the isolates from both bulk tank milk and clinical mastitis were of similar genetic background. This suggests that dairy cows are natural carriers of the S. aureus subtypes that cause clinical mastitis if the right conditions are present and that a broad range of subtypes cause mastitis. A phylogenetic cluster that mostly consisted of ST151 isolates carried three mobile genetic elements that were primarily found in this group. The prevalence of resistance genes was generally low. However, the first ST398 methicillin resistant S. aureus isolate from a Danish dairy cow with clinical mastitis was detected. Copyright © 2018 Elsevier B.V. All rights reserved.

Isolation and Characteristics of Shiga Toxin 2f-Producing Escherichia coli among Pigeons in Kyushu, Japan

PubMed Central

Murakami, Koichi; Etoh, Yoshiki; Ichihara, Sachiko; Maeda, Eriko; Takenaka, Shigeyuki; Horikawa, Kazumi; Narimatsu, Hiroshi; Kawano, Kimiko; Kawamura, Yoshiaki; Ito, Kenitiro

2014-01-01

An increasing number of Shiga toxin 2f-producing Escherichia coli (STEC2f) infections in humans are being reported in Europe, and pigeons have been suggested as a reservoir for the pathogen. In Japan, there is very little information regarding carriage of STEC2f by pigeons, prompting the need for further investigation. We collected 549 samples of pigeon droppings from 14 locations in Kyushu, Japan, to isolate STEC2f and to investigate characteristics of the isolates. Shiga toxin stx 2f gene fragments were detected by PCR in 16 (2.9%) of the 549 dropping samples across four of the 14 locations. We obtained 23 STEC2f-isolates from seven of the original samples and from three pigeon dropping samples collected in an additional sampling experiment (from a total of seven locations across both sampling periods). Genotypic and phenotypic characteristics were then examined for selected isolates from each of 10 samples with pulsed-field gel electrophoresis profiles. Eight of the stx 2f gene fragments sequenced in this study were homologous to others that were identified in Europe. Some isolates also contained virulence-related genes, including lpfA O26, irp 2, and fyuA, and all of the 10 selected isolates maintained the eae, astA, and cdt genes. Moreover, five of the 10 selected isolates contained sfpA, a gene that is restricted to Shiga toxin-producing E. coli O165:H2 and sorbitol-fermenting Shiga toxin-producing E. coli O157:NM. We document serotypes O152:HNM, O128:HNM, and O145:H34 as STEC2f, which agrees with previous studies on pigeons and humans. Interestingly, O119:H21 was newly described as STEC2f. O145:H34, with sequence type 722, was described in a German study in humans and was also isolated in the current study. These results revealed that Japanese zoonotic STEC2f strains harboring several virulence-related factors may be of the same clonal complexes as some European strains. These findings provide useful information for public health-related disease management

Biochemical and Molecular Analysis of Staphylococcus aureus Clinical Isolates from Hospitalized Patients.

PubMed

Karmakar, Amit; Dua, Parimal; Ghosh, Chandradipa

2016-01-01

Staphylococcus aureus is opportunistic human as well as animal pathogen that causes a variety of diseases. A total of 100 Staphylococcus aureus isolates were obtained from clinical samples derived from hospitalized patients. The presumptive Staphylococcus aureus clinical isolates were identified phenotypically by different biochemical tests. Molecular identification was done by PCR using species specific 16S rRNA primer pairs and finally 100 isolates were found to be positive as Staphylococcus aureus. Screened isolates were further analyzed by several microbiological diagnostics tests including gelatin hydrolysis, protease, and lipase tests. It was found that 78%, 81%, and 51% isolates were positive for gelatin hydrolysis, protease, and lipase activities, respectively. Antibiogram analysis of isolated Staphylococcus aureus strains with respect to different antimicrobial agents revealed resistance pattern ranging from 57 to 96%. Our study also shows 70% strains to be MRSA, 54.3% as VRSA, and 54.3% as both MRSA and VRSA. All the identified isolates were subjected to detection of mecA, nuc, and hlb genes and 70%, 84%, and 40% were found to harbour mecA, nuc, and hlb genes, respectively. The current investigation is highly important and informative for the high level multidrug resistant Staphylococcus aureus infections inclusive also of methicillin and vancomycin.

[The in vitro antifungal activities of fluconazole against pathogenic yeasts recently isolated from clinical specimens].

PubMed

Yamaguchi, H; Igari, J; Kume, H; Abe, M; Oguri, T; Kanno, H; Kawakami, S; Okuzumi, K; Fukayama, M; Ito, A; Kawata, K; Uchida, K

1997-09-01

The emergence of Candida albicans resistance to azole antifungal agents have been reported in the U. S. and Europe. We examined the in vitro antifungal activities of fluconazole against clinical isolates collected by seven investigators in three years to examine if a tendency existed toward the development of azole-resistance among fungal isolates in Japan. The following results were obtained: 1. Sensitivities to fluconazole (FLCZ) were determined for yeast-like fungi, including 113 strains isolated in 1993, 149 strains isolated in 1994 and 205 strains isolated in 1995. No significant differences in sensitivities in the three years were detected. 2. Minimum inhibitory concentrations of FLCZ were 0.1-0.78 microgram/ml for C. albicans and 3.13-25 micrograms/ml for C. glabrata. Strains with 25 micrograms/ml of FLCZ's MIC were detected; two strains of C. krusei and one strain each of C. krusei, Trichospron beigelii and Hansenula anomala. No strains with higher than 50 micrograms/ml MIC of FLCZ were detected. 3. In vitro activities of FLCZ were compared between clinical strains isolated between 1993 and 1995 and clinical strains isolated before the marketing of FLCZ (up to December 1987) or clinical yeasts isolated between 1991 and 1992. No significant differences were observed, suggesting that no tendency existed toward azole resistance among fungal strains examined.

Cronobacter sakazakii clinical isolates overcome host barriers and evade the immune response.

PubMed

Almajed, Faisal S; Forsythe, Stephen J

2016-01-01

Cronobacter sakazakii is the most frequently clinically isolated species of the Cronobacter genus. However the virulence factors of C. sakazakii including their ability to overcome host barriers remains poorly studied. In this study, ten clinical isolates of C. sakazakii were assessed for their ability to invade and translocate through human colonic carcinoma epithelial cells (Caco-2) and human brain microvascular endothelial cells (HBMEC). Their ability to avoid phagocytosis in human macrophages U937 and human brain microglial cells was investigated. Additionally, they were tested for serum sensitivity and the presence of the Cronobacter plasminogen activation gene (cpa) gene, which is reported to confer serum resistance. Our data showed that the clinical C. sakazakii strains invaded and translocated through Caco-2 and HBMEC cell lines and some strains showed significantly higher levels of invasion and translocation. Moreover, C. sakazakii was able to persist and even multiply in phagocytic macrophage and microglial cells. All strains, except one, were able to withstand human serum exposure, the single serum sensitive strain was also the only one which did not encode for the cpa gene. These results demonstrate that C. sakazakii clinical isolates are able to overcome host barriers and evade the host immune response indicating their capacity to cause diseases such as necrotizing enterocolitis (NEC) and meningitis. Our data showed for the first time the ability of C. sakazakii clinical isolates to survive and multiply within human microglial cells. Additionally, it was shown that C. sakazakii clinical strains have the capacity to translocate through the Caco-2 and HBMEC cell lines paracellularly. Copyright © 2015 Elsevier Ltd. All rights reserved.

Identification, epidemiological relatedness, and biofilm formation of clinical Chryseobacterium indologenes isolates from central Taiwan.

PubMed

Chang, Yi-Cheng; Lo, Hsueh-Hsia; Hsieh, Hsiu-Ying; Chang, Shan-Min

2015-10-01

The clinical impact of Chryseobacterium indologenes infection is increasing; nevertheless, most studies had been conducted in northern Taiwan, but rarely in central Taiwan. Using 16S rRNA gene sequencing, 34 isolates of C. indologenes were identified at the Central Region Hospital Alliance between 2007 and 2011. Vitek 2 and matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) methods were compared for the feasibility to identify this bacterium. Drug susceptibility test, biofilm formation, and pulsed-field gel electrophoresis (PFGE) were also performed. All isolates were collected from hospitalized patients with an average age of 70.8 ± 18.5 years. The most prevalent sample was urine (50.0%), followed by sputum (32.4%). The accuracy rate of species-level identification reached 94.1% using the Vitek 2 method and 85.3% using the MALDI-TOF MS method. All of the isolates were resistant to gentamicin, amikacin, ceftriaxone, chloramphenicol, colistin, and imipenem, but completely susceptible to minocycline. While analyzing biofilm-forming ability, 38.2% (13/34) of C. indologenes isolates displayed a positive phenotype using the Luria-Bertani (LB) medium. However, 80.0% (4/5) of invasive isolates were biofilm producers. Based on PFGE analysis, several clusters were found, and the possible intrahospital spread of this bacterium in this area could not be excluded. Both Vitek 2 and MALDI-TOF MS methods showed good ability in the determination of C. indologenes. Among the examined drugs, minocycline was the most potent one. As many as 38.2% C. indologenes isolates showed biofilm-forming ability. PFGE analyses revealed the possible intrahospital transmission of this bacterium in central Taiwan. Copyright © 2014. Published by Elsevier B.V.

Clinical Manifestations and Molecular Characterization of Pertactin-Deficient and Pertactin-Producing Bordetella pertussis in Children, Philadelphia 2007-2014.

PubMed

Vodzak, Jennifer; Queenan, Anne Marie; Souder, Emily; Evangelista, Alan T; Long, Sarah S

2017-01-01

 Bordetella pertussis strains lacking expression of pertactin, a bacterial adhesin and vaccine target, are emerging. There are limited data on disease manifestations of mutant strains in children. We sought to compare clinical manifestations of pertactin-deficient and pertactin-producing B. pertussis infection in infants and describe corresponding molecular characteristics.  Molecular characterization of archived B. pertussis isolates (collected January 2007 to March 2014) included Western blot analysis, pulsed-field gel electrophoresis (PFGE), polymerase chain reaction, and pertactin gene sequencing. Medical record review compared epidemiologic and clinical courses of pertactin-producing and pertactin-deficient B. pertussis infections.  Sixty of 72 B. pertussis isolates were viable for analysis. Within the cohort of infants, the median age was 95 days, 90% received ≤1 dose of vaccine, and 72% were hospitalized. Pertactin deficiency was first noted in 2008, and its prevalence increased over time (68% overall prevalence). There were no statistically significant differences in presenting symptoms or signs, hospitalization, intensive care, respiratory support, or laboratory results related to pertactin expression. Illness length was shorter in pertactin-deficient group (mean difference, 3.2 days; P = .04); no difference was noted in the subgroup of infants <4 months old. Molecular analyses identified 11 PFGE profiles (Centers for Disease Control and Prevention profile No. 002 predominant, 47%). In 41 pertactin-deficient strains, sequencing identified 2 stop codon and 3 IS481 locations disrupting the prn gene. Mutations and nucleotide positions were not unique to PFGE type, nor were they clustered in time.  In this cohort of predominantly unimmunized infants, clinical disease did not differ between infection with pertactin-deficient and those with pertactin-producing B. pertussis. Molecular analyses demonstrated remarkable PFGE strain diversity, with multiple

Antilisterial Activity of Nisin-Like Bacteriocin-Producing Lactococcus lactis subsp. lactis Isolated from Traditional Sardinian Dairy Products

PubMed Central

Cosentino, Sofia; Fadda, Maria Elisabetta; Deplano, Maura; Melis, Roberta; Pomata, Rita; Pisano, Maria Barbara

2012-01-01

With the aim of selecting LAB strains with antilisterial activity to be used as protective cultures to enhance the safety of dairy products, the antimicrobial properties of 117 Lactococcus lactis subsp. lactis isolated from artisanal Sardinian dairy products were evaluated, and six strains were found to produce bacteriocin-like substances. The capacity of these strains to antagonize Listeria monocytogenes during cocultivation in skimmed milk was evaluated, showing a reduction of L. monocytogenes counts of approximately 4 log units compared to the positive control after 24 h of incubation. In order for a strain to be used as bioprotective culture, it should be carefully evaluated for the presence of virulence factors, to determine what potential risks might be involved in its use. None of the strains tested was found to produce biogenic amines or to possess haemolytic activity. In addition, all strains were sensitive to clinically important antibiotics such as ampicillin, tetracycline, and vancomycin. Our results suggest that these bac+ strains could be potentially applied in cheese manufacturing to control the growth of L. monocytogenes. PMID:22536018

Fluoroquinolone resistance in clinical and environmental isolates of Escherichia coli in Mexico City.

PubMed

Amábile-Cuevas, C F; Arredondo-García, J L; Cruz, A; Rosas, Irma

2010-01-01

To assess the different phenotypes and mechanisms of fluoroquinolone (FQ) resistance in clinical and environmental isolates of Escherichia coli. We compared FQ-resistant E. coli isolates, measuring minimal inhibitory concentrations (MIC) of ciprofloxacin, along with susceptibility to other antibiotics. We also searched for the presence of efflux pumps, using efflux inhibitors, and for plasmid-borne FQ-resistance by PCR. We found that, aside from the higher FQ-resistance prevalence among clinical strains, environmental ones resist much lower concentrations of ciprofloxacin. Efflux pumps mediate fluoroquinolone resistance as frequently among environmental isolates than in clinical strains. Plasmid-borne qnrA genes were not detected in any resistant strain. Environmental FQ-resistant strains may have a nonclinical origin and/or a selective pressure different from the clinical use of FQs. The identification of the source of low-level FQ-resistant strains (ciprofloxacin MIC c. 8 microg ml(-1)) in the environment could be important to curb the rapid emergence and spread of FQ-resistance in clinical settings, as these strains can easily become fully resistant to FQ concentrations achievable in fluids and tissues during therapy.

Efflux Pump Gene Expression in Multidrug-Resistant Mycobacterium tuberculosis Clinical Isolates

PubMed Central

Jiang, Yi; Wei, Jianhao; Zhao, Li-li; Zhao, Xiuqin; Lu, Jianxin; Wan, Kanglin

2015-01-01

Isoniazid (INH) and rifampicin (RIF) are the two most effective drugs in tuberculosis therapy. Understanding the molecular mechanisms of resistance to these two drugs is essential to quickly diagnose multidrug-resistant (MDR) tuberculosis and extensive drug-resistant tuberculosis. Nine clinical Mycobacterium tuberculosis isolates resistant to only INH and RIF and 10 clinical pan-sensitive isolates were included to evaluate the expression of 20 putative drug efflux pump genes and sequence mutations in rpoB (RIF), katG (INH), the inhA promoter (INH), and oxyR-ahpC (INH). Nine and three MDR isolates were induced to overexpress efflux pump genes by INH and RIF, respectively. Eight and two efflux pump genes were induced to overexpress by INH and RIF in MDR isolates, respectively. drrA, drrB, efpA, jefA (Rv2459), mmr, Rv0849, Rv1634, and Rv1250 were overexpressed under INH or RIF stress. Most efflux pump genes were overexpressed under INH stress in a MDR isolates that carried the wild-type katG, inhA, and oxyR-ahpC associated with INH resistance than in those that carried mutations. The expression levels of 11 genes (efpA, Rv0849, Rv1250, P55 (Rv1410c), Rv1634, Rv2994, stp, Rv2459, pstB, drrA, and drrB) without drug inducement were significantly higher (P < 0.05) in nine MDR isolates than in 10 pan-sensitive isolates. In conclusion, efflux pumps may play an important role in INH acquired resistance in MDR M. tuberculosis, especially in those strains having no mutations in genes associated with INH resistance; basal expression levels of some efflux pump genes are higher in MDR isolates than in pan-sensitive isolates and the basal expressional differences may be helpful to diagnose and treat resistant tuberculosis. PMID:25695504

Molecular analysis of the integrons of metallo-β-lactamase-producing Pseudomonas aeruginosa isolates collected by nationwide surveillance programs across Japan.

PubMed

Mano, Yoko; Saga, Tomoo; Ishii, Yoshikazu; Yoshizumi, Ayumi; Bonomo, Robert A; Yamaguchi, Keizo; Tateda, Kazuhiro

2015-02-21

We investigate the evolving molecular epidemiology of metallo-β-lactamase (MBL)-producing Pseudomonas aeruginosa isolates collected in a 100 institution, nationwide surveillance study in Japan from 2004 to 2006. MBL-producers were detected in 23/996 isolates (2.3%) in 2004 and 21/992 (2.1%) in 2006. Antimicrobial resistance (specifically, carbapenem resistance) rates between two periods did not differ significantly. MBL-producers were more prevalent in urinary tract isolates. bla IMP-1 group was the most predominant (38 isolates, 80%), followed by 3 bla IMP-7, 2 bla IMP-11 group, and 1 bla VIM-1. All MBL genes were identified in 16 different class 1 integrons, most of which were novel to INTEGRALL database. A total of 17 isolates of sequence type (ST) 235, a recognized worldwide drug-resistant lineage, were distributed in 5 geographic regions across Japan. ST235 isolates included a sublineage associated with In113-like integron. ST357 was identified in 14 isolates, 9 of which harboring a sole bla IMP-1 gene cassette (In994) were recovered from Chugoku region in 2004. ST357 isolates with bla IMP-11 group or ST235 with bla IMP-7 emerged in 2006. We also report for the first time the presence of novel fosI gene cassette in strains other than Mycobacterium spp. Our data give an important "snapshot" of the molecular characteristics and dynamics of MBL-producing lineages in P. aeruginosa in Japan. The significant association of specific genotypes and integrons implies that dissemination and transmission of the preexisting resistant lineage, rather than horizontal gene transfer in situ, might largely explain their endemicity.

Asperger syndrome, violent thoughts and clinically isolated syndrome.

PubMed

Vanderbruggen, N; Van Geit, N; Bissay, V; Zeeuws, D; Santermans, L; Baeken, C

2010-12-01

A young man, 23 years old, with a clinically isolated syndrome (CIS), presented violent thoughts during a neurological consultation. He was diagnosed with Asperger Syndrome based on a psychiatric and (neuro)psychological examination. Possible risk factors for acting-out and the implications for treatment, if CIS would evolve to MS, are discussed based on a review of the literature.

A nucleotide sequence comparison of coxsackievirus B4 isolates from aquatic samples and clinical specimens.

PubMed Central

Hughes, M. S.; Hoey, E. M.; Coyle, P. V.

1993-01-01

Ten coxsackievirus B4 (CVB4) strains isolated from clinical and environmental sources in Northern Ireland in 1985-7, were compared at the nucleotide sequence level. Dideoxynucleotide sequencing of a polymerase chain reaction (PCR) amplified fragment, spanning the VP1/P2A genomic region, classified the isolates into two distinct groups or genotypes as defined by Rico-Hesse and colleagues for poliovirus type 1. Isolates within each group shared approximately 99% sequence identity at the nucleotide level whereas < or = 86% sequence identity was shared between groups. One isolate derived from a clinical specimen in 1987 was grouped with six CVB4 isolates recovered from the aquatic environment in 1986-7. The second group comprised CVB4 isolates from clinical specimens in 1985-6. Both groups were different at the nucleotide level from the prototype strain isolated in 1950. It was concluded that the method could be used to sub-type CVB4 isolates and would be of value in epidemiological studies of CVB4. Predicted amino acid sequences revealed non-conservation of the tyrosine residue at the VP1/P2A cleavage site but were of little value in distinguishing CVB4 variants. PMID:8386098

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

PubMed

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

2001-02-01

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

Fluoroquinolone-resistant and extended-spectrum β-lactamase-producing Escherichia coli from the milk of cows with clinical mastitis in Southern Taiwan.

PubMed

Su, Yaochi; Yu, Chang-You; Tsai, Yilin; Wang, Shao-Hung; Lee, Chihan; Chu, Chishih

2016-12-01

Escherichia coli is a common pathogen to cause clinical and subclinical mastitis in cows. A total of 57 E. coli isolates from raw milk from cows were characterized genetically and biochemically. Extended-spectrum β-lactamase (ESBL) genes, the mechanism for fluoroquinolone resistance, and variations in virulence genes and genomes of these E. coli isolates were investigated by the antimicrobial susceptibility test, simplex and multiplex polymerase chain reaction (PCR), and pulsed-field gel electrophoresis (PFGE). All E. coli isolates were resistant to cloxacillin (100%) and to a lesser extent (50%) to tetracycline, neomycin, gentamycin, ampicillin, ceftriaxone, cefotaxime (CTX), and ceftazidime (CAZ). Nearly 70% of the isolates were resistant to at least two antimicrobials and 28.1% carried AmpA and AmpC genes simultaneously. The predominant bla gene was bla TEM , followed by bla CMY , bla CTX , bla SHV , and bla DHA. Among the six (10.5%) ESBL-producing E. coli carrying bla CTX-M15 , bla CTX-M55 , or bla CTX-M14 , two isolates 31 of ST410 in the ST23 complex and 58 of ST167 in the ST10 complex were also resistant to ciprofloxacin, enrofloxacin, and levofloxacin, with mutations at codon 83 from serine to leucine and codon 87 from aspartic acid to asparagine in GyrA and at codon 80 from serine to isoleucine in ParC. These isolates were genetically diverse in pulsotype analysis, lacked toxin genes of human pathogenic E. coli and carried mostly the prevalent virulence genes fimH, papGII, and α-hemolysin. Lacking virulence genes examined, genetic diverse E. coli isolates are unrelated to human pathogenic E. coli. Enhancing sanitation in milk processing and transportation is needed to eliminate multidrug-resistant (MDR), fluoroquinolone-resistant, and ESBL-producing E. coli isolates. Copyright © 2014. Published by Elsevier B.V.

Genomic Characterization of Listeria monocytogenes Isolates Associated with Clinical Listeriosis and the Food Production Environment in Ireland

PubMed Central

Hilliard, Amber; Leong, Dara; O’Callaghan, Amy; Culligan, Eamonn P.; Morgan, Ciara A.; DeLappe, Niall; Hill, Colin; Cormican, Martin; Gahan, Cormac G.M.

2018-01-01

Listeria monocytogenes is a major human foodborne pathogen that is prevalent in the natural environment and has a high case fatality rate. Whole genome sequencing (WGS) analysis has emerged as a valuable methodology for the classification of L. monocytogenes isolates and the identification of virulence islands that may influence infectivity. In this study, WGS was used to provide an insight into 25 L. monocytogenes isolates from cases of clinical infection in Ireland between 2013 and 2015. Clinical strains were either lineage I (14 isolates) or lineage II (11 isolates), with 12 clonal complexes (CC) represented, of which CC1 (6) and CC101 (4) were the most common. Single nucleotide polymorphism (SNP) analysis demonstrated that clinical isolates from mother–infant pairs (one isolate from the mother and one from the infant) were highly related (3 SNP differences in each) and also identified close similarities between isolates from otherwise distinct cases (1 SNP difference). Clinical strains were positive for common virulence-associated loci and 13 isolates harbour the LIPI-3 locus. Pulsed-field gel electrophoresis (PFGE) was used to compare strains to a database of 1300 Irish food and food processing environment isolates and determined that 64% of clinical pulsotypes were previously encountered in the food or food processing environment. Five of the matching food and food processing environment isolates were sequenced and results demonstrated a correlation between pulsotype and genotype. Overall, the work provides insights into the nature of L. monocytogenes strains currently causing clinical disease in Ireland and indicates that similar isolates can be found in the food or food processing environment. PMID:29558450

Phenotypic Characteristics Associated with Virulence of Clinical Isolates from the Sporothrix Complex

PubMed Central

Almeida-Paes, Rodrigo; de Oliveira, Luã Cardoso; Oliveira, Manoel Marques Evangelista; Gutierrez-Galhardo, Maria Clara; Nosanchuk, Joshua Daniel; Zancopé-Oliveira, Rosely Maria

2015-01-01

The Sporothrix complex members cause sporotrichosis, a subcutaneous mycosis with a wide spectrum of clinical manifestations. Several specific phenotypic characteristics are associated with virulence in many fungi, but studies in this field involving the Sporothrix complex species are scarce. Melanization, thermotolerance, and production of proteases, catalase, and urease were investigated in 61 S. brasiliensis, one S. globosa, and 10 S. schenckii strains. The S. brasiliensis strains showed a higher expression of melanin and urease compared with S. schenckii. These two species, however, presented similar thermotolerances. Our S. globosa strain had low expression of all studied virulence factors. The relationship between these phenotypes and clinical aspects of sporotrichosis was also evaluated. Strains isolated from patients with spontaneous regression of infection were heavily melanized and produced high urease levels. Melanin was also related to dissemination of internal organs and protease production was associated with HIV-coinfection. A murine sporotrichosis model showed that a S. brasiliensis strain with high expression of virulence factors was able to disseminate and yield a high fungal burden in comparison with a control S. schenckii strain. Our results show that virulence-related phenotypes are variably expressed within the Sporothrix complex species and might be involved in clinical aspects of sporotrichosis. PMID:25961005

Veterinary Hospital Dissemination of CTX-M-15 Extended-Spectrum Beta-Lactamase-Producing Escherichia coli ST410 in the United Kingdom.

PubMed

Timofte, Dorina; Maciuca, Iuliana Elena; Williams, Nicola J; Wattret, Andrew; Schmidt, Vanessa

2016-10-01

We characterized extended-spectrum beta-lactamases (ESBLs) and plasmid-mediated quinolone resistance (PMQR) in 32 Escherichia coli extended spectrum cephalosporin (ESC)-resistant clinical isolates from UK companion animals from several clinics. In addition, to investigate the possible dissemination of ESBL clinical isolates within a veterinary hospital, two ESBL-producing E. coli isolates from a dog with septic peritonitis and a cluster of environmental ESC-resistant E. coli isolates obtained from the same clinic and during the same time period, as these two particular ESBL-positive clinical isolates, were also included in the study. Molecular characterization identified bla CTX-M to be the most prevalent gene in ESC-resistant isolates, where 66% and 27% of clinical isolates carried bla CTX-M-15 and bla CTX-M-14, respectively. The only PMQR gene detected was aac(6')-Ib-cr, being found in 34% of the ESC E. coli isolates and was associated with the carriage of bla CTX-M-15 . The clinical and environmental isolates investigated for hospital dissemination had a common ESBL/AmpC phenotype, carried bla CTX-M-15 , and co-harbored bla OXA-1, bla TEM-1, bla CMY-2, and aac(6')-Ib-cr. Multilocus sequence typing identified them all as ST410, while pulse-field gel electrophoresis demonstrated 100% homology of clinical and environmental isolates, suggesting hospital environmental dissemination of CTX-M-15-producing E. coli ST410.

Novel Mutations in pncA Gene of Pyrazinamide Resistant Clinical Isolates of Mycobacterium tuberculosis.

PubMed

Kahbazi, Manijeh; Sarmadian, Hossein; Ahmadi, Azam; Didgar, Farshideh; Sadrnia, Maryam; Poolad, Toktam; Arjomandzadegan, Mohammad

2018-04-16

In clinical isolates of Mycobacterium tuberculosis (MTB), resistance to pyrazinamide occurs by mutations in any positions of the pncA gene (NC_000962.3) especially in nucleotides 359 and 374. In this study we examined the pncA gene sequence in clinical isolates of MTB. Genomic DNA of 33 clinical isolates of MTB was extracted by the Chelex100 method. The polymerase chain reactions (PCR) were performed using specific primers for amplification of 744 bp amplicon comprising the coding sequences (CDS) of the pncA gene. PCR products were sequenced by an automated sequencing Bioscience system. Additionally, semi Nested-allele specific (sNASP) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods were carried out for verification of probable mutations in nucleotides 359 and 374. Sequencing results showed that from 33 MTB clinical isolates, nine pyrazinamide-resistant isolates have mutations. Furthermore, no mutation was detected in 24 susceptible strains in the entire 561 bp of the pncA gene. Moreover, new mutations of G→A at position 3 of the pncA gene were identified in some of the resistant isolates. Results showed that the sNASP method could detect mutations in nucleotide 359 and 374 of the pncA gene, but the PCR-RFLP method by the SacII enzyme could not detect these mutations. In conclusion, the identification of new mutations in the pncA gene confirmed the probable occurrence of mutations in any nucleotides of the pncA gene sequence in resistant isolates of MTB.

Molecular characterization of ESBL-producing Escherichia coli isolates from hospital- and community-acquired infections in NW Mexico.

PubMed

Miranda-Romero, Ana Laura; Silva-Sanchez, Jesus; Garza-Ramos, Ulises; Barrios, Humberto; Sánchez-Pérez, Alejandro; Reyna-Flores, Fernando

2017-01-01

We investigated the molecular characteristics of ESBL-producing E. coli (ESBL-PEc) isolates from two hospitals and community settings in Ciudad Obregon, Sonora, Mexico. Between 2011 and 2014, thirty-seven ESBL-PEc isolates were collected. The major encoded ESBL was the bla CTX-M-15 gene (97%); followed by 13.5% of the bla SHV-12 gene, and 5.5% encoded the bla TLA-1 gene. The PMQR gene aac(6´)-Ib-cr was detected in 97% of the isolates and the qnrB gene, in one isolate. The ESBL-PEc isolates corresponded to phylogenetic group B2, ST131. Our results highlight the dissemination of ESBL-PEc isolates in northwest Mexico (Ciudad Obregon, Sonora). Copyright © 2016 Elsevier Inc. All rights reserved.

In vitro susceptibility of Candida albicans clinical isolates to eight antifungal agents in Ouagadougou (Burkina Faso).

PubMed

Zida, A; Yacouba, A; Bamba, S; Sangare, I; Sawadogo, M; Guiguemde, T; Kone, S; Traore, L K; Ouedraogo-Traore, R; Guiguemde, R T

2017-12-01

In recent years, the infection Candida albicans infection worldwide has risen, and the incidence of resistance to traditional antifungal therapies is also increasing. The aim of this study was to evaluate in vitro susceptibility of C. albicans clinical isolates to eight antifungal agents in Ouagadougou. A cross-sectional study was conducted from January 2013 to December 2015 at Yalgado Ouédraogo University Teaching Hospital. Two hundred seven strains have been isolated from 347 symptomatic patients received in different clinical services. Samples were cultured on Sabouraud Dextrose Agar supplemented with Cloramphenicol. Isolates were diagnosed as C. albicans using germ tube test, chlamydospore formation on Corn Meal Agar, and Api-Candida test (Biomérieux). Antifungal susceptibility testing was performed by disk diffusion method and isolates classified as susceptible, susceptible dose-dependent and resistant. Three hundred forty-seven (347) patients are included in this study. Two hundred and six (206) out of 347 collected samples (59.36%) were found positive for C. albicans. The strains were mostly isolated from vulvovaginal (49%) and oral infections (40.3%). The highest resistance rates of azoles were obtained with fluconazole (66.5%), itraconazole (52.3%) and ketoconazole (22.9%) when all clinical isolates were included. The resistance rates of fluconazole, itraconazole and ketoconazole remain highest for vulvovaginal and oral isolates. The rate of resistance to the polyene amphotericin B was 32.0% for all clinical isolates and was 56.4% for vulvovaginal strains. Resistance rate to nystatin was 6.3% for all clinical isolates. Cross-resistance analysis with data of all clinical strains revealed that the incidence of resistance to ketoconazole and itraconazole in fluconazole-resistant isolates was significantly higher than recorded for fluconazole-susceptible isolates. In vitro C. albicans antifungal susceptibility test in this study showed relatively high

Isolation and partial characterization of Streptococcus suis from clinical cases in cattle.

PubMed

Okwumabua, Ogi; Peterson, Hanna; Hsu, Hui-Min; Bochsler, Phil; Behr, Melissa

2017-03-01

Sixteen isolates of gram-positive, coccoid bacteria were obtained from clinical cases of diverse conditions in cattle and identified as Streptococcus suis using 16S ribosomal DNA gene sequencing and other bacterial identification methods. None of the isolates could be assigned to any of the known S. suis capsular types. Virulence-associated gene profiling that targeted muramidase-released protein, extracellular protein factor, suilysin, 89-kb pathogenicity island, and arginine deiminase ( arcA) genes were negative except for 1 isolate that was arcA positive. The arcA-positive isolate caused severe widespread lesions, including multiorgan suppurative and hemorrhagic inflammation in the meninges, lung, liver, spleen, lymph nodes, and serosae of heart and intestines. The other isolates were primarily associated with meningitis, bronchopneumonia, and multifocal acute necrotizing hepatitis. The isolates differed from each other by 4-6 fragments when examined by pulsed-field gel electrophoresis, indicating they are possibly related. The isolates were susceptible to ampicillin, penicillin, and tiamulin. Resistance was noted to sulfadimethoxine (93%), oxytetracycline (86%), chlortetracycline (86%), neomycin (67%), tilmicosin (47%), clindamycin (47%), enrofloxacin (33%), gentamicin (13%), florfenicol (7%), trimethoprim-sulfamethoxazole (7%), and spectinomycin (53%). Multi-drug resistance (defined as resistance to at least 1 agent in 3 or more antimicrobial classes) was detected in 67% of the isolates. The pathology observations provide evidence that S. suis may be an important pathogen of bovine calves. S. suis is an agent that clinical bacteriology laboratories should consider when dealing with cases involving cattle.

Dissemination of IMP-6 metallo-β-lactamase-producing Pseudomonas aeruginosa sequence type 235 in Korea.

PubMed

Seok, Yoonmi; Bae, Il Kwon; Jeong, Seok Hoon; Kim, Soo Hyun; Lee, Hyukmin; Lee, Kyungwon

2011-12-01

To investigate the epidemiological traits of Pseudomonas aeruginosa clinical isolates producing metallo-β-lactamases (MBLs) in Korea. A total of 386 non-duplicate P. aeruginosa clinical isolates were collected from Korea in 2009. Detection of MBL genes was performed by PCR. The genetic organization of class 1 integrons carrying the MBL gene cassette was investigated by PCR mapping and sequencing. The epidemiological relationships of the isolates were investigated by multilocus sequence typing and PFGE. Of 386 P. aeruginosa isolates, 30 (7.8%) isolates carried the bla(IMP-6) gene and 1 (0.3%) isolate carried the bla(VIM-2) gene. A probe specific for the bla(IMP-6) gene was hybridized to an ∼950 kbp I-CeuI-macrorestriction fragment from all 30 isolates and a probe specific for the bla(VIM-2) gene also hybridized to an ∼500 kbp I-CeuI-macrorestriction fragment from 1 isolate (BDC10). All 31 MBL-producing isolates shared an identical sequence type (ST), ST235, and they carried the same bla(OXA-50) allelic type, bla(OXA-50g). All MBL-producing isolates showed similar XbaI-macrorestriction patterns (similarity >85%), irrespective of MBL genotype. P. aeruginosa ST235 carrying the chromosomally located bla(IMP-6) gene is widely disseminated in Korea.

Multilocus variable-number tandem-repeat analysis of clinical isolates of Aspergillus flavus from Iran reveals the first cases of Aspergillus minisclerotigenes associated with human infection

PubMed Central

2014-01-01

Background Aspergillus flavus is intensively studied for its role in infecting crop plants and contaminating produce with aflatoxin, but its role as a human pathogen is less well understood. In parts of the Middle East and India, A. flavus surpasses A. fumigatus as a cause of invasive aspergillosis and is a significant cause of cutaneous, sinus, nasal and nail infections. Methods A collection of 45 clinical and 10 environmental A. flavus isolates from Iran were analysed using Variable-Number Tandem-Repeat (VNTR) markers with MICROSAT and goeBURST to determine their genetic diversity and their relatedness to clinical and environmental A. flavus isolates from Australia. Phylogeny was assessed using partial β-tubulin and calmodulin gene sequencing, and mating type was determined by PCR. Antifungal susceptibility testing was performed on selected isolates using a reference microbroth dilution method. Results There was considerable diversity in the A. flavus collection, with no segregation on goeBURST networks according to source or geographic location. Three Iranian isolates, two from sinus infections and one from a paranasal infection grouped with Aspergillus minisclerotigenes, and all produced B and G aflatoxin. Phylogenic analysis using partial β-tubulin and calmodulin sequencing confirmed two of these as A. minisclerotigenes, while the third could not be differentiated from A. flavus and related species within Aspergillus section flavi. Based on epidemiological cut-off values, the A. minisclerotigens and A. flavus isolates tested were susceptible to commonly used antifungal drugs. Conclusions This is the first report of human infection due to A. minisclerotigenes, and it raises the possiblity that other species within Aspergillus section flavi may also cause clinical disease. Clinical isolates of A. flavus from Iran are not distinct from Australian isolates, indicating local environmental, climatic or host features, rather than fungal features, govern the high

A Hemorrhagic Factor (Apicidin) Produced by Toxic Fusarium Isolates from Soybean Seeds

PubMed Central

Park, Jun-Suk; Lee, Kyung-Rim; Kim, Jin-Cheol; Lim, Sun-Hee; Seo, Jeong-Ah; Lee, Yin-Won

1999-01-01

Fifty-two isolates of Fusarium species were obtained from soybean seeds from various parts of Korea and identified as Fusarium oxysporum, F. moniliforme, F. semitectum, F. solani, F. graminearum, or F. lateritium. These isolates were grown on autoclaved wheat grains and examined for toxicity in a rat-feeding test. Nine cultures were toxic to rats. One of these, a culture of Fusarium sp. strain KCTC 16677, produced apicidin, an antiprotozoal agent that caused toxic effects in rats (including body weight loss; hemorrhage in the stomach, intestines, and bladder; and finally death) when rats were fed diets supplemented with 0.05 and 0.1% apicidin. The toxin was toxic to brine shrimp (the 50% lethal concentration was 40 μg/ml) and was weakly cytotoxic to human and mouse tumor cell lines. PMID:9872769

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

Isolation and identification of cellulose-producing strain Komagataeibacter intermedius from fermented fruit juice.

PubMed

Lin, Shin-Ping; Huang, Yin-Hsuan; Hsu, Kai-Di; Lai, Ying-Jang; Chen, Yu-Kuo; Cheng, Kuan-Chen

2016-10-20

A bacterial cellulose (BC) producing strain isolated from fermented fruit juice was identified as Komagataeibacter intermedius (K. intermedius) FST213-1 by 16s rDNA sequencing analysis and biochemical characteristics test. K. intermedius FST213-1 can produce BC within pH 4-9 and exhibit maximum BC production (1.2g/L) at pH 8 in short-term (4-day) cultivation. Results of Fourier transform infrared spectroscopy, X-ray diffraction, water content, thermogravimetric analysis and mechanical property indicated that BC produced from K. intermedius FST213-1 exhibits higher water content ability (99.5%), lower thermostability (315°C), lower crystallinity (79.3%) and similar mechanical properties in comparison with the specimen from model BC producer, Gluconacetobacter xylinus 23769. Based on these analyses, the novel based-resistant strain K. intermedius FST213-1 can efficiently produce BC, which can be applied for industrial manufacturing with potential features. Copyright © 2016 Elsevier Ltd. All rights reserved.

The effect of propolis honey candy on C. Albicans and clinical isolate biofilms viability (in-vitro)

NASA Astrophysics Data System (ADS)

Soekanto, Sri Angky; Bachtiar, Endang W.; Ramadhan, Amatul Firdaus; Febrina, Riri; Sahlan, Muhamad

2018-02-01

The objective of this study was to analyze the effectiveness of Propolis honey candy on the formation of C. Albicans ATCC 10231 and Clinical Isolate biofilms. C. Albicans ATCC 10231 and Clinical Isolate were cultured on 96-wellplates that were previously coated with saliva and serum on each well plate. On each group, a solution of Propolis honey candy, X candy, and honey candy was distributed with a 50% concentration of solution. The well plates were then tested using MTT assay. For the X Candy, both C. Albicans ATCC 10231 and Clinical Isolate biofilms that were coated with saliva and serum showed a significant increase of biofilm formation (0.669±0.320) compared to the control (0.223±0.138). However, there were no significant differences between Propolis honey candy (0.171±0.120) and honey candy (0.217±0.112) in the formation of C. Albicans ATCC 10231 and Clinical Isolate biofilms compared to control. Propolis honey candy has a tendency to decrease the formation of C. Albicans ATCC 10231 and Clinical Isolate biofilms.

Sub-typing of extended-spectrum-β-lactamase-producing isolates from a nosocomial outbreak: application of a 10-loci generic Escherichia coli multi-locus variable number tandem repeat analysis.

PubMed

Karami, Nahid; Helldal, Lisa; Welinder-Olsson, Christina; Ahrén, Christina; Moore, Edward R B

2013-01-01

Extended-spectrum β-lactamase producing Escherichia coli (ESBL-E. coli) were isolated from infants hospitalized in a neonatal, post-surgery ward during a four-month-long nosocomial outbreak and six-month follow-up period. A multi-locus variable number tandem repeat analysis (MLVA), using 10 loci (GECM-10), for 'generic' (i.e., non-STEC) E. coli was applied for sub-species-level (i.e., sub-typing) delineation and characterization of the bacterial isolates. Ten distinct GECM-10 types were detected among 50 isolates, correlating with the types defined by pulsed-field gel electrophoresis (PFGE), which is recognized to be the 'gold-standard' method for clinical epidemiological analyses. Multi-locus sequence typing (MLST), multiplex PCR genotyping of bla CTX-M, bla TEM, bla OXA and bla SHV genes and antibiotic resistance profiling, as well as a PCR assay specific for detecting isolates of the pandemic O25b-ST131 strain, further characterized the outbreak isolates. Two clusters of isolates with distinct GECM-10 types (G06-04 and G07-02), corresponding to two major PFGE types and the MLST-based sequence types (STs) 131 and 1444, respectively, were confirmed to be responsible for the outbreak. The application of GECM-10 sub-typing provided reliable, rapid and cost-effective epidemiological characterizations of the ESBL-producing isolates from a nosocomial outbreak that correlated with and may be used to replace the laborious PFGE protocol for analyzing generic E. coli.

The Defect in Autophagy Induction by Clinical Isolates of Mycobacterium Tuberculosis Is Correlated with Poor Tuberculosis Outcomes.

PubMed

Li, Furong; Gao, Bo; Xu, Wei; Chen, Ling; Xiong, Sidong

2016-01-01

Tuberculosis (TB) represents a major global health problem. The prognosis of clinically active tuberculosis depends on the complex interactions between Mycobacterium tuberculosis (Mtb) and its host. In recent years, autophagy receives particular attention for its role in host defense against intracellular pathogens, including Mtb. In present study, we aim to investigate the relationship of autophagy induction by clinical isolates of Mtb with the clinical outcomes in patients with TB. We collected 185 clinical isolates of Mtb, and determined the effect of these Mtb isolates on autophagy induction in macrophages. It was found that most of clinical isolates of Mtb were able to induce autophagosome formation in macrophages, however, the autophagy-inducing ability varied significantly among different isolates. Of importance, our results revealed that patients infected by Mtb with poor autophagy-inducing ability displayed more severe radiographic extent of disease (p<0.001), and were more likely to have unfavorable treatment outcomes (p<0.001). No significant association was observed between the extent of Mtb-induced autophagy with some socio-demographic characteristics (such as gender, age and tobacco consumption), and some laboratory tests (such as hemoglobin, leukocyte count and erythrocyte sedimentation rate). Furthermore, results from logistic regression analysis demonstrated that the defect in autophagy induction by clinical isolates of Mtb was an independent risk factor for far-advanced radiographic disease (aOR 4.710 [1.93-11.50]) and unfavorable treatment outcomes (aOR 8.309 [2.22-28.97]) in TB. These data indicated that the defect in autophagy induction by Mtb isolates increased the risk of poor clinical outcomes in TB patients, and detection of clinical isolates-induced autophagosome formation might help evaluate the TB outcomes.

Bioconversion of α-chitin into N-acetyl-glucosamine using chitinases produced by marine-derived Aeromonas caviae isolates.

PubMed

Cardozo, Flávio Augusto; Gonzalez, Juan Miguel; Feitosa, Valker Araujo; Pessoa, Adalberto; Rivera, Irma Nelly Gutierrez

2017-10-27

N-Acetyl-D-glucosamine (GlcNAc) is a monosaccharide with great application potential in the food, cosmetic, pharmaceutical, and biomaterial areas. GlcNAc is currently produced by chemical hydrolysis of chitin, but the current processes are environmentally unfriendly, have low yield and high cost. This study demonstrates the potential to produce GlcNAc from α-chitin using chitinases of ten marine-derived Aeromonas isolates as a sustainable alternative to the current chemical process. The isolates were characterized as Aeromonas caviae by multilocus sequence analysis (MLSA) using six housekeeping genes (gltA, groL, gyrB, metG, ppsA, and recA), not presented the virulence genes verified (alt, act, ast, ahh1, aer, aerA, hlyA, ascV and ascFG), but showed hemolytic activity on blood agar. GlcNAc was produced at 37 °C, pH 5.0, 2% (w/v) colloidal chitin and crude chitinase extracts (0.5 U mL -1 ) by all the isolates with yields from 14 to 85% at 6 h, 17-89% at 12 h and 19-93% after 24 h. The highest yield of GlcNAc was observed by A. caviae CH129 (93%). This study demonstrates one of the most efficient chitin enzymatic hydrolysis procedures and A. caviae isolates with great potential for chitinases expression and GlcNAc production.

Mycobacterium tuberculosis Isolates from Single Outpatient Clinic in Panama City Exhibit Wide Genetic Diversity

PubMed Central

Sambrano, Dilcia; Correa, Ricardo; Almengor, Pedro; Domínguez, Amada; Vega, Silvio; Goodridge, Amador

2014-01-01

Understanding Mycobacterium tuberculosis biodiversity and transmission is significant for tuberculosis control. This short report aimed to determine the genetic diversity of M. tuberculosis isolates from an outpatient clinic in Panama City. A total of 62 M. tuberculosis isolates were genotyped by 12 loci mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) and Spoligotyping. Forty-five (72.6%) of the isolates showed unique MIRU-VNTR genotypes, and 13 (21%) of the isolates were grouped into four clusters. Four isolates showed polyclonal MIRU-VNTR genotypes. The MIRU-VNTR Hunter-Gaston discriminatory index reached 0.988. The Spoligotyping analysis revealed 16 M. tuberculosis families, including Latin American-Mediterranean, Harlem, and Beijing. These findings suggest a wide genetic diversity of M. tuberculosis isolates at one outpatient clinic. A detailed molecular epidemiology survey is now warranted, especially following second massive immigration for local Panama Canal expansion activities. PMID:24865686

Postantifungal effect of the combination of caspofungin with voriconazole and amphotericin B against clinical Candida krusei isolates.

PubMed

Oz, Yasemin; Kiremitci, Abdurrahman; Dag, Ilknur; Metintas, Selma; Kiraz, Nuri

2013-01-01

We evaluated the postantifungal effects (PAFEs) of caspofungin (CAS), voriconazole (VOR), amphotericin B (AmB), and the combinations of CAS + VOR and CAS + AmB against 30 clinical Candida krusei isolates at 0.25, 1 and 4 times the MIC of each individually and in the indicated combinations. Antifungals were removed after 1 hour and colony counts were performed at 0, 2, 6, 24, and 48 h. VOR did not display any measurable PAFE regardless of antifungal concentrations, while AmB and CAS exhibited dose-dependent PAFE. The most effective agent producing a prolonged PAFE in this study was CAS. Although the combination of CAS with VOR generated longer PAFEs at 0.25 and 1 times their respective MICs in comparison with CAS alone, this combination was indifferent rather than synergistic. However, the combination of CAS with AmB at 4 times their MICs exhibited the best performance, reducing the colony counts during the 48 h after removal of drugs and resulted in synergic interaction in respect to 20 (67%) isolates. Consequently, CAS has a prolonged PAFE in vitro against C. krusei isolates, and the combination of AmB + CAS may increase significantly the efficacy of CAS. Our data may be useful in optimizing dosing regimens for these agents and their combinations, although further studies are needed to explore the clinical usefulness of our results.

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.

Levofloxacin Efflux and smeD in Clinical Isolates of Stenotrophomonas maltophilia.

PubMed

Chong, So Young; Lee, Kyungwon; Chung, Hae-Sun; Hong, Seong Geun; Suh, Younghee; Chong, Yunsop

2017-03-01

Trimethoprim-sulfamethoxazole is the first-line antimicrobial combination for Stenotrophomonas maltophilia infections. However, allergy or intolerance and increasing resistance limit the use of trimethoprim-sulfamethoxazole. Quinolones can be used as an alternative therapeutic option, but resistance can emerge rapidly during therapy. We analyzed the contribution of SmeABC and SmeDEF efflux pumps to levofloxacin resistance in clinical isolates of S. maltophilia. Nonduplicate clinical isolates of S. maltophilia were collected in 2010 from 11 university hospitals (n = 102). Fifty-five levofloxacin nonsusceptible (minimum inhibitory concentration [MIC] ≥4 μg/ml) and 47 susceptible (MIC ≤2 μg/ml) isolates were tested for efflux pump overexpression. Real-time reverse transcription-PCR was performed for amplification and quantification of smeB, smeC, smeD, and smeF mRNA. To determine which antimicrobials were affected by smeD overexpression, the growth rates of a levofloxacin-susceptible S. maltophilia isolate were compared by measuring absorbance of antimicrobial-supplemented Luria-Bertani broth (LB) cultures with or without triclosan. Significant relationships between sme gene overexpression and resistance were observed for smeD against levofloxacin, smeC and smeF against ceftazidime, and smeC against ticarcillin-clavulanate. The mean MICs of moxifloxacin and tigecycline did not significantly differ for isolates with or without overexpression of smeB, smeC, and smeF, but were significantly higher for isolates with smeD overexpression. The mean MICs of amikacin were significantly higher for smeC or smeF overexpressing isolates. Increased growth of a levofloxacin-susceptible isolate was observed in LB with 1/2 MIC levofloxacin in the presence of triclosan. These data suggest that the expression of smeD plays a role in levofloxacin resistance in S. maltophilia.