[Molecular analysis of vancomycin-resistant enterococci isolated from clinical samples] (original) (raw)
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Advances in medicine, 2016
Geographic spread of vancomycin-resistant enterococci (VRE) clones in cities, countries, or even continents has been identified by molecular techniques. This study aimed at characterizing virulent genes and determining genetic relatedness of 45 VRE isolates from Trinidad and Tobago using molecular tools, including polymerase chain reaction, pulsed-field gel electrophoresis (PFGE), and Random Amplification Polymorphic DNA (RAPD). The majority (84%) of the isolates were Enterococcus faecium possessing vanA gene while the rest (16%) were Enterococcus faecalis possessing vanB. The esp gene was found in all 45 VRE isolates while hyl genes were found only in E. faecium species. The E. faecium species expressed five distinct PFGE patterns. The predominant clones with similar or common patterns belonged to clones one and three, and each had 11 (29%) of the VRE isolates. Plasmid content was identified in representative isolates from each clonal group. By contrast, the E. faecalis species had one PFGE pattern suggesting the presence of an occult and limited clonal spread. The emergence of VRE in the country seems to be related to intra/interhospital dissemination of an epidemic clone carrying the vanA element. Therefore, infection control measures will be warranted to prevent any potential outbreak and spread of VRE in the country.
Journal of Antimicrobial Chemotherapy, 2002
Geographic spread of vancomycin-resistant enterococci (VRE) clones in cities, countries, or even continents has been identified by molecular techniques. This study aimed at characterizing virulent genes and determining genetic relatedness of 45 VRE isolates from Trinidad and Tobago using molecular tools, including polymerase chain reaction, pulsed-field gel electrophoresis (PFGE), and Random Amplification Polymorphic DNA (RAPD). The majority (84%) of the isolates were Enterococcus faecium possessing vanA gene while the rest (16%) were Enterococcus faecalis possessing vanB. The esp gene was found in all 45 VRE isolates while hyl genes were found only in E. faecium species. The E. faecium species expressed five distinct PFGE patterns. The predominant clones with similar or common patterns belonged to clones one and three, and each had 11 (29%) of the VRE isolates. Plasmid content was identified in representative isolates from each clonal group. By contrast, the E. faecalis species had one PFGE pattern suggesting the presence of an occult and limited clonal spread. The emergence of VRE in the country seems to be related to intra/interhospital dissemination of an epidemic clone carrying the vanA element. Therefore, infection control measures will be warranted to prevent any potential outbreak and spread of VRE in the country.
PloS one, 2017
Emergence of vancomycin-resistant Enterococci (VRE) that first appeared on the stage about three decades ago is now a major concern worldwide as it has globally reached every continent. Our aim was to simply undertake a multinational study to delineate the resistance and virulence genes of clinical isolates of VRE isolates from the Caribbean. We employed both conventional (standard microbiological methods including use of E-test strips, chromogenic agar) and molecular methods (polymerase chain reactions-PCR, pulsed-field gel electrophoresis-PFGE and multilocus sequence typing-MLST) to analyze and characterize 245 Enterococci species and 77 VRE isolates from twelve hospitals from eight countries in the Caribbean. The PCR confirmed and demonstrated the resistance and virulence genes (vanA and esp) among all confirmed VRE isolates. The PFGE delineated clonally related isolates from patients from the same country and other countries in the region. The main sequence types of the VRE isol...
2017
A total of 98 vancomycin-resistant Enterococcus faecium (VREF) isolates from four tertiary-care hospitals in Korea during the period between 1998 and 2004 were analyzed for genotypic characteristics using the multiplex PCR, multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), and esp gene analysis. Ninety-two isolates of VREF with VanA phenotype and five of six isolates with VanB phenotype possessed the vanA gene. MLST analysis revealed 9 sequence types (STs), which belonged to a single clonal complex (CC78, clonal lineage C1). Five strains showing incongruence between phenotype and genotype (VanB-vanA) did not belong to the same genotypic clone. The esp gene was detected in all VREF strains, showing 12 different esp repeat profiles. Data suggest that an epidemic clonal group of VREF, CC78 with esp gene, is also present in Asia and has differentiated into multiple diverse genotypic clones during the evolutionary process.
Molecular epidemiology of vancomycin-resistant enterococci in Singapore
Pathology, 2009
Enterococcus faecium has emerged as an important nosocomial pathogen worldwide, and this trend has been associated with the dissemination of a genetic lineage designated clonal cluster 17 (CC17). Enterococcal isolates were collected prospectively (2006 to 2008) from 32 hospitals in Colombia, Ecuador, Perú, and Venezuela and subjected to antimicrobial susceptibility testing. Genotyping was performed with all vancomycin-resistant E. faecium (VREfm) isolates by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing. All VREfm isolates were evaluated for the presence of 16 putative virulence genes (14 fms genes, the esp gene of E. faecium [esp Efm ], and the hyl gene of E. faecium [hyl Efm ]) and plasmids carrying the fms20-fms21 (pilA), hyl Efm , and vanA genes. Of 723 enterococcal isolates recovered, E. faecalis was the most common (78%). Vancomycin resistance was detected in 6% of the isolates (74% of which were E. faecium). Eleven distinct PFGE types were found among the VREfm isolates, with most belonging to sequence types 412 and 18. The ebpA Efm -ebpB Efm -ebpC Efm (pilB) and fms11-fms19-fms16 clusters were detected in all VREfm isolates from the region, whereas esp Efm and hyl Efm were detected in 69% and 23% of the isolates, respectively. The fms20-fms21 (pilA) cluster, which encodes a putative pilus-like protein, was found on plasmids from almost all VREfm isolates and was sometimes found to coexist with hyl Efm and the vanA gene cluster. The population genetics of VREfm in South America appear to resemble those of such strains in the United States in the early years of the CC17 epidemic. The overwhelming presence of plasmids encoding putative virulence factors and vanA genes suggests that E. faecium from the CC17 genogroup may disseminate in the region in the coming years.
Innovative Publication, 2016
Background: Enterococci are gram positive cocci which reside as commensal microbial flora in gastrointestinal tract, vagina, biliary tract and male urethra. E.faecalis is the predominant species followed by E.faecium. Resistance against glycopeptides and aminoglycosides are being increasingly demonstrated and that is conferred upon largely by van A gene. Aims: To isolate and speciate Enterococci from various clinical samples, antibiogram pattern determination, followed by genotyping of vancomycin resistant Enterococci. Settings and Design: Prospective study. Materials and Methods: 200 Enterococcal isolates were collected and processed for speciation based on battery of phenotypic characteristics. Antibiotic sensitivity testing was performed as per CLSI guidelines 2014 for glycopeptide and aminoglycoside antibiotics. Enterococci which were resistant to vancomycin were subjected to polymerase chain reaction for van A gene detection. Statistical analysis used: Nil. Results: Of the 200 isolates 5 were resistant to vancomycin and teicoplanin (2.5%), 30 were resistant to high level gentamicin (15%). van A gene was detected in 3 of the 5 vancomycin resistant isolates. E.faecium was observed to be more resistant to the antimicrobials. Conclusions: If the vancomycin resistance in Enterococci gets dispersed throughout the world, it may pose a challenge in the treatment of Gram positive infections and may lead to treatment failure. Further treatment options may not be available. Hence these infections have to be prevented and the sequence of development of resistance to higher drugs has to be controlled by active surveillance and prevention.
Indian Journal of Medical Microbiology, 2014
This report describes the frequency of Enteroccoci phenotypic and genotypic susceptibility patterns of VRE (Vancomycin Resistant Enterococci) from three hospitals in Tehran, Iran. One hundred and twenty enterococcal urine cultures were isolate from patients with urinary tract infection (UTI). After identification of enterococcal species by biochemical tests, glycopeptide susceptibility of each isolate was assessed by disk agar diffusion method according to NCCLS guideline. Glycopeptide minimum inhibitory concentration (MIC) for each VRE isolate was determined by the agar dilution method and the vanA gene was detected by PCR. Seven percent (8/120) of the isolates were VRE, including E. faecalis 38% (3/8), E. faecium 25% (2/8), E. mundtii 25% (2/8), and E. raffinosus 12% (1/8). All 8 isolates resistant to vancomycin showed vancomycin MIC of >512µg/ml, and teicoplanin MIC's ranging from 8->64µg/ml, and they all possessed the vanA gene. Six (75%) of VRE were isolated from a referral tertiary care hospital, i.e. Ahari Children Medical Center (ACMC). Almost 90% of Enterococci were E. faecalis (57%) and E. faecium (30%). The remaining 13% were identified as E. mundtii (6%), E. avium (3%), E. durans (1%), E. hirea (2%), and E. raffinosus (1%). The diverse VRE species combined with high rate of VRE isolation in Iran, as well as isolation of E. raffinosus and E. mundtii in the Middle East (ME) region for the first time, suggests a rapid spread of resistance among Enterococci along with an emerging shift in VRE distribution in Iran.
TURKISH JOURNAL OF MEDICAL SCIENCES, 2016
Introduction Enterococci are the natural members of the gastrointestinal tract, mouth, urethra, and vaginal flora and may result in serious nosocomial infections despite their low virulence characteristics. Enterococci are often isolated particularly from patients in intensive care units with suppressed immune systems, hematological malignancies, catheter and prosthesis existence, prolonged hospitalization duration, and usage of broad-spectrum antibiotics (1). The first vancomycin-resistant Enterococcus strain in the world was reported by Uttley et al. (2) in the UK in 1988. In Turkey, the first vancomycin-resistant Enterococcus strain was reported in a pediatric patient by Vural et al. (3) from Akdeniz University in 1998. Resistance to vancomycin develops with the vanA and vanB genes coded by plasmids and vanC, vanD, and vanG coded by chromosomes. The most common multidrug Background/aim: Enterococci play an important role in nosocomial infections. Therefore, this study investigates multidrug resistance (MDR)1 gene areas in the pathogenicity of enterococci and virulence genes in both vancomycin-sensitive enterococci (VSE) and vancomycin-resistant enterococci (VRE) strains. Materials and methods: Virulence genes and MDR genes of enterococci were investigated by polymerase chain reaction (PCR). Results: We evaluated a total of 116 isolates, 93 being VRE and 23 being VSE. In this study, 95.6% of VRE (n = 93) were Enterococcus faecium (n = 89) and 4.3% were E. faecalis (n = 4), while 17.4% of VSE (n = 23) were E. faecium (n = 4) and 82.6% were E. faecalis (n = 19). The vanA MDR1 gene was detected in all VRE isolates. Among virulence genes, esp and hyl were detected in E. faecium, an enterococcus with the highest resistance to vancomycin, and gelE was detected in E. faecalis, an enterococcus with the highest sensitivity to vancomycin. Three or more virulence genes were identified only in VSE strains. We consider that it is a significant result that VSE had more virulence genes than VRE. Only esp was seen in VRE E. faecium strains. Conclusion: This study includes experimental results on the association of virulence characteristics in VRE and VSE strains.
Journal of Clinical Microbiology, 2010
Enterococcus faecium has emerged as an important nosocomial pathogen worldwide, and this trend has been associated with the dissemination of a genetic lineage designated clonal cluster 17 (CC17). Enterococcal isolates were collected prospectively (2006 to 2008) from 32 hospitals in Colombia, Ecuador, Perú, and Venezuela and subjected to antimicrobial susceptibility testing. Genotyping was performed with all vancomycin-resistant E. faecium (VREfm) isolates by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing. All VREfm isolates were evaluated for the presence of 16 putative virulence genes (14 fms genes, the esp gene of E. faecium [esp Efm ], and the hyl gene of E. faecium [hyl Efm ]) and plasmids carrying the fms20-fms21 (pilA), hyl Efm , and vanA genes. Of 723 enterococcal isolates recovered, E. faecalis was the most common (78%). Vancomycin resistance was detected in 6% of the isolates (74% of which were E. faecium). Eleven distinct PFGE types were found among the VREfm isolates, with most belonging to sequence types 412 and 18. The ebpA Efm -ebpB Efm -ebpC Efm (pilB) and fms11-fms19-fms16 clusters were detected in all VREfm isolates from the region, whereas esp Efm and hyl Efm were detected in 69% and 23% of the isolates, respectively. The fms20-fms21 (pilA) cluster, which encodes a putative pilus-like protein, was found on plasmids from almost all VREfm isolates and was sometimes found to coexist with hyl Efm and the vanA gene cluster. The population genetics of VREfm in South America appear to resemble those of such strains in the United States in the early years of the CC17 epidemic. The overwhelming presence of plasmids encoding putative virulence factors and vanA genes suggests that E. faecium from the CC17 genogroup may disseminate in the region in the coming years.
Diversity of vancomycin-resistant enterococci in a low endemicity area
Journal of Global Antimicrobial Resistance, 2014
Vancomycin-resistant enterococci (VRE) are one of the most frequent nosocomial pathogens worldwide. Vancomycin resistance is reported in 15-25% of Enterococcus faecium and 2-3% of Enterococcus faecalis in the UK and in 80% of E. faecium and 7% of E. faecalis in the USA. This vancomycin resistance is mediated by vanA or vanB genes. vanA-type VRE is predominant in Europe, the USA and South Korea, whereas vanB type is predominant in Singapore and Australia [1]. Multilocus sequence typing (MLST) is used for genotyping of VRE, and several clonal complexes (CCs) have been identified. Enterococcus faecium CC17 (now subdivided into sequence type ST17, ST18 and ST78 lineages) is the most prevalent genotype in nosocomial settings [2]. Most E. faecium strains belonging to CC17 are ampicillin-resistant, which may facilitate their nosocomial transmission. Several sequence types are regionally predominant, for example ST203 in Australia and ST17 in Singapore, although predominant sequence types may change over time [3,4]. The number of VRE infections in Japan is as low as ca. 100 per year (http://idsc.nih.go.jp/idwr/ydata/report-Ea.html). Despite several outbreak reports of VRE in Japan, regional spread was reported in only one area [5-8]. Moreover, only one study has reported on the epidemiology of VRE using MLST [7], which indicated that ST78 vanA-type E. faecium was predominant in a region of Japan, and no studies have been reported on virulence genes.