Vancomycin Resistance among Enterococci: Further Limiting Our Therapeutic Options

Introduction: Enterococci are indigenous flora of theintestinal tract, oral cavity & genitourinary tract of human.Over recent years, there is increased interest in Enterococcinot only because of their serious infections but becauseof their increasing resistance to many antimicrobials.Vancomycin being the only alternative available. But over thetime, there has been increase in Vancomycin Resistance whichhas spread globally. The aim of this study was to determinethe prevalence of Vancomycin Resistant Enterococci (VRE)isolated from various clinical specimens in a tertiary carehospital in North India.Material and methods: A cross-sectional study was conductedin the Department of Microbiology, Government MedicalCollege, Amritsar from July 1st, 2018 to June 30th, 2019. Allthe samples received were processed and identification ofEnterococci was made by using standard microbiologicaltechniques. Antimicrobial susceptibility was performed byKirby Bauer disc diffusion method as per CLSI guidelines.Results: Out of total clinical samples (11,098), 3,551 (31.9%)were found to be culture positive. Among the culture positive,91 (2.56%) isolates were identified as Enterococcus speciescomprising of 37 E.faecalis (41%) and 54 E.faecium (59%).Maximum number of Enterococci were isolated from urinesamples (54.92%) followed by pus & body fluids (38.02%) andblood (7.04%). 9.52% of E.faecium isolates were found to beresistant to vancomycin. All the strains were 100% susceptibleto Linezolid, Teicoplanin & Quinupristin-dalfopristin.Conclusion: Enterococci have become the major pathogenicbacteria that cause hospital-acquired infections due tomultiple-antimicrobial resistance. VRE has emerged asimportant nosocomial pathogen and pose serious threat topatients. Vancomycin should be cautiously used else wewould be left with very few therapeutic options.

Detection of various virulence factors in high level aminoglycoside resistance and vancomycin resistant enterococci isolates of uropathogenic Enterococci

Background: Enterococci are common commensal organism of enteric tract and act as opportunistic pathogen and may cause infection in community as well as in hospitalised individuals. In present study association of several types of virulence factors like haemolysin, gelatinase and biofilm formation have been studied among HLAR and Vancomycin resistant Enterococci (VRE) isolates of enterococci among UTI patients.Methods: The samples were collected from all hospitalized and OPD patients of MBS Hospital, JK Lone Hospital and NMC Hospital. Government Medical College, Kota, Rajasthan, India. A total of 360 isolates of enterococcus were collected during the period of 2 years from April 2016 to April 2018 in microbiology laboratory, Department of Microbiology, Government Medical College, Kota, Rajasthan, India. All virulence factors were detected by phenotypic methods and MIC values were detected for high level gentamicin and vancomycin.Results: Among all enterococcal isolates most common factor was biofilm production 191 (53.05%) followed by haemolysin 131 (36.38%) and gelatinase production 72 (20%). Total resistant (MIC> 500 µg/ml) isolates for gentamicin was 194 (89.4%). In agar dilution 14 (11.2%) isolates were found sensitive, 61 (48.8%) isolates were found intermediate and 50 (40%) isolates were found to be resistant for vancomycin. HLAR and VRE was maximum associated with haemolysin + bio-film followed by gelatinase+biofilm, haemolysin+gelatinase+bio- film and least with haemolysin + gelatinase.Conclusions: In present study enterococcus show significant production of biofilm and other virulence factors. With production of biofilm they become more resistant to routinely used concentration of antibiotics posing threat for treatment failure. A continuous monitoring is needed particularly for resistance to aminoglycoside and vancomycin to stop their institutional spread. Judicial use of antibiotics should be encouraged both in community as well as in institutions.

Assessment of Antimicrobial Resistance in the Food Chains in Norway

The Norwegian Food Safety Authority (NFSA) asked the Norwegian Scientific Committee for Food Safety (Vitenskapskomiteen for mattrygghet, VKM) for an assessment of antimicrobial resistance (AMR) in the food chains in Norway, with focus on each of the following food chains: pigs and pork products; poultry, eggs and poultry products; cattle and bovine products; aquaculture and aquaculture products; fresh produce (fruit, berries, and vegetables); and drinking water. AMR in imported food has not been assessed in this report. AMR in Norwegian food chains has been assessed in terms of probability of exposure to humans. Due to data constraints, it has not been possible to assess the consequences of this exposure for human health. VKM appointed a working group consisting of three members of the Panel on Biological Hazards, one member of Panel on Animal Health and Welfare, and four external experts to prepare a draft Opinion document and the answer the questions. The Panel on Biological Hazards has reviewed and revised the draft prepared by the working group and approved the Opinion document «Assessment of antimicrobial resistance in the food chains in Norway”. AMR can be described as the ability of a bacterium to withstand the effects of an antimicrobial. The clinical antimicrobial resistance crisis has focused attention on all uses of antimicrobial agents, including their use in human medicine, veterinary medicine, and in agriculture and aquaculture. AMR is considered the greatest challenge to face health care in 21st century, and there is increasing concern and debate about which roles the food production chains play as reservoirs and disseminators of AMR. This assessment addresses several food chains. The report does not characterise all forms of AMR that may occur in these chains, but puts emphasis on the resistant bacteria and resistance determinants that have emerged at the animal-human interface in recent decades. VKM’s choice is based on zoonotic potential and the limited alternatives available for treatment of infections. In order for a comprehensive and detailed assessment to be conducted, these particular resistance forms need to be characterised and assessed separately. At an overall level, the hazard regarding exposure of humans to antimicrobial resistant bacteria from cattle, milk/milk products, fish/fish products/seafood, fresh produce, water, and food processing in Norway is considered by VKM to be negligible. Current data regarding possible pathways for transmission of LA-MRSA via contaminated food/meat to the broader human population fail to implicate LA-MRSA from pigs as a foodborne pathogen. Compared with other animal products, poultry and poultry products are regarded as the most important reservoirs of ESBL/AmpC-producing Enterobacteriaceae, quinolone-resistant E. coli (QREC), and their corresponding resistance determinants. The probability of human exposure of ESBL/AmpC-producing Enterobacteriaceae and QREC via poultry is assessed as being non-negligible. Probability of AMR Transfer Associated with Food and Uncertainties: In this assessment, the probability of transmission of AMR from food chains to humans has been either categorized as negligible or non-negligible according to the following definitions: Negligible – the probability of transfer of AMR is extremely low. Negligible probability should be considered insignificant. Non-negligible – the probability of transfer of AMR is greater than negligible. Non-negligible probability should be considered significant, but the available data are currently insufficient to enable discrimination between the different levels. Lack of data has made it difficult to reach any firm conclusions regarding the probability of AMR transmission from food to humans in Norway. Similarly, ranking the probabilities with regard to relative importance is largely not possible with the data available. The probability of transfer of AMR from cattle, milk/milk products, fish, seafood, and drinking water has been assessed to be negligible. The probability of transfer of LA-MRSA from live pigs to humans is considered to be non-negligible, while the probability of transfer from pork to humans has been assessed to be negligible. The probability of transfer of ESBL/AmpC-producing Enterobacteriaceae, quinolone-resistant E. coli, and their respective corresponding genes from live poultry and poultry meat is considered as non-negligible. Processing of food, such as cooking or preservation, can reduce the number of bacteria in the products and thus decrease the transmission of antimicrobial resistant bacteria from food to humans. It should be noted that both categories of probabilities (negligible and non-negligible) in this assessment are associated with a number of uncertainties. Bacteria are living organisms that are under continuous evolution, and are able to adapt rapidly to changing living conditions. This report is an assessment of the current situation with regards to development and dissemination of antibiotic resistant bacteria and their resistance genes in the food chain. This situation may change as the bacteria continue to adapt to the selection pressures exerted by the worldwide use of antimicrobials. Such bacterial changes, sometimes occurring VKM Report 2015:29 9 in “quantum leaps” due to horizontal gene transfer (HGT), may also rapidly change the probability of transfer of resistance to specific antimicrobials. Data Gaps: There is a lack of knowledge regarding the vast reservoir of AMR in the environmental, animal, and food reservoirs. Furthermore, there is lack of data regarding the routes and frequencies of transmission of AMR from live, food-producing animals and foodstuffs of different origins to humans and vice versa.

Clonal dissemination of vancomycin-resistant Enterococcus faecium ST412 in a Brazilian region

ABSTRACT Vancomycin-resistant Enterococcus faecium (VREfm) has emerged as an important global nosocomial pathogen, and this trend is associated with the spread of high-risk clones. Here, we determined the genetic and phenotypic features of 93 VREfm isolates that were obtained from patients in 13 hospitals in Vitória, Espírito Santo, Brazil, during 2012-2013. All the isolates were vancomycin-resistant and harbored the vanA gene. Only 6 (6.5%) of the VREfm isolates showed the ability to form biofilm. The 93 isolates analyzed belong to a single pulsed-field gel electrophoresis lineage and presented six subtypes. MLST genotyping showed that all VREfm belonged to ST412 (the high-risk clone, hospital-adapted). The present study describes the dissemination of ST412 clone in the local hospitals. The clonal spread of these ST412 isolates in the area we analyzed as well as other hospitals in southeastern Brazil supports the importance of identifying and controlling the presence of these microorganisms in health care-related services.

Detection of vancomycin-resistant enterococci (VRE) in stool specimens submitted for Clostridium difficile toxin testing

Abstract The aim of this study was to determine the association between Clostridium difficile (C. difficile) and vancomycin-resistant Enterococcus (VRE) and efficacy of screening stools submitted for C. difficile toxin assay for prevalence of VRE. Between April 2012 and February 2014, 158 stool samples submitted for C. difficile toxin to the Marmara University Microbiology Laboratory, were included in the study. Stool samples were analyzed by enzyme immuno assay test; VIDAS (bioMerieux, France) for Toxin A&B. Samples were inoculated on chromID VRE (bioMerieux, France) and incubated 24 h at 37 °C. Manuel tests and API20 STREP (bioMerieux, France) test were used to identify the Enterococci species. After the species identification, vancomycin and teicoplanin MIC's were performed by E test and molecular resistance genes for vanA vs vanB were detected by polymerase chain reaction (PCR). Of the 158 stool samples, 88 were toxin positive. The prevalence of VRE was 17%(n:19) in toxin positives however, 11.4% in toxin negatives(n:70). All VRE isolates were identified as Enterococcus faecium. These results were evaluated according to Fischer's exact chi-square test and p value between VRE colonization and C. difficile toxin positivity was detected 0.047 (p < 0.05). PPV and NPV were 79% and 47% respectively. In our study, the presence of VRE in C. difficile toxin positives is statistically significant compared with toxin negatives (p < 0.05). Screening for VRE is both additional cost and work load for the laboratories. Therefore VRE screening among C. difficile toxin positive samples, will be cost effective for determination of high risk patients in the hospitals especially for developing countries.

Emergence of vanA gene among vancomycin-resistant enterococci in a tertiary care hospital of North - East India.

Background & objectives: Vancomycin-resistant enterococci (VRE) have become one of the most challenging nosocomial pathogens with the rapid spread of the multi-drug resistant strain with limited therapeutic options. It is a matter of concern due to its ability to transfer vancomycin resistant gene to other organisms. The present study was undertaken to determine the emergence of vancomycin-resistant enterococci and the vanA gene among the isolates in a tertiary care hospital of North-East India. Methods: A total of 67 consecutive enterococcal isolates from different clinical samples were collected and identified by using the standard methods. Antibiogram was done by disk diffusion method and VRE was screened by the disk diffusion and vancomycin supplement agar dilution method. The minimum inhibitory concentration (MIC) value for vancomycin was determined by E-test. The VRE isolates were analyzed by PCR for vanA gene. Results: A total of 54 (81%) Enterococcus faecalis and 13 (19%) E. faecium were detected among the clinical isolates and 16 (24%) were VRE. The VRE isolates were multidrug resistant and linezolid resistance was also found to be in three. MIC range to vancomycin was 16-32 μg/ml among the VRE. The vanA gene was found in nine of 16 VRE isolates. Interpretation & conclusions: Emergence of VRE and presence of vanA in a tertiary care hospital setting in North-East India indicate toward a need for implementing infection control policies and active surveillance.

Prevalence and Risk Factors for Vancomycin Resistant Enterococci Isolated from Clinical Samples in Kashmir, North India: A Hospital Based Study.

Aims: To find out the prevalence and risk factors for vancomycin resistant Enterococci in a leading tertiary care center of north India. Design: Cross sectional study. Place and Duration of Study: Sher-I-Kashmir Institute of Medical Sciences, Srinagar. Kashmir. One year study. Methodology: A total of 400 isolates of Enterococci from patients admitted to our hospital were recovered using standard microbiological procedures, during a period of one year. Antimicrobial susceptibility of these isolates to various antibiotics was performed according to Clinical Laboratory Standard Institute (CLSI) guidelines. Minimum inhibitory concentration (MIC) of isolates found to be resistant to vancomycin on disc diffusion was done by microbroth dilution method. Various risk factors like placement of IV line catheter, urinary catheter, hospital stay and prior use of antimicrobial agents was noted for all the patients. Results: A total of 25 (6.3%) isolates of Enterococci were found to be vancomycin resistant, most of them recovered from the blood samples. E. faecium 16 (64%) was the predominant VRE isolated followed by E. faecalis 9 (36%). Factors like stay in an ICU, prior use of antimicrobials, placement of IV line and urinary catheter were associated with vancomycin resistant Enterococci (VRE) acquisition. Conclusion: VRE were recovered from our hospital and strict adherence to infection control guidelines needs to be followed to control their dissemination.

Gut Microbiota in Graft-versus-Host Disease

Gut microbiota inhabit the host gastrointestinal (GI) tract and play roles in many aspects of metabolic and immunologic homeostasis. Understanding about gut microbiota composition in health and disease is accumulating with the advances in gene sequencing technology. Graft-versus-host disease (GVHD) is a major complication after allogenic bone marrow transplantation (allo-BMT), a gold standard clinical procedure to treat hematologic disorders such as leukemia and lymphomas. Recent studies have shown that a disturbance in the gut microbiota affects GVHD prognosis. Decrease in a compositional diversity is suggested as an independent predictor of GVHD and colonization of noncommensal Enterococcus is shown to be involved in unpleasant treatment outcomes. This article describes current understanding about allo-BMT-induced gut microbiota changes and its involvement in the incidence of GVHD. In addition, several putative therapeutic strategies to decrease GVHD-related mortality after allo-BMT are discussed.

Comparison of Three Chromogenic Media for Recovery of Vancomycin-Resistant Enterococci from Rectal Swab Samples / 대한임상미생물학회지

BACKGROUND: Three chromogenic media using direct inoculation were compared with enriched enterococcosel broth for vancomycin-resistant Enterococcus faecium and/or Enterococcus faecalis (VRE) surveillance. METHODS: A total of 174 rectal swabs were included for VRE surveillance. The specimens were transferred in enterococcosel broth (EB). An aliquot of the broth was inoculated onto Brilliance VRE, chromID VRE, and VRESelect media and incubated for up to 48 h. We examined each media and EB after 24 h and 48 h of incubation. When appropriately colored colonies were observed, identification was confirmed using the VITEK-2 system and/or VITEK MS. Vancomycin susceptibility was confirmed by disk diffusion test. The presence of resistance genes was confirmed using Anyplex VanR Real-time Detection (Seegene, Korea). RESULTS: Of the 174 rectal swab specimens, 73 VRE were isolated. For enterococcosel broth, Brilliance VRE, chromID VRE, and VRESelect, the sensitivity at 24 h was 79.2%, 83.3%, 79.2%, and 79.2%, respectively. The sensitivity at 48 h was 91.7%, 93.1%, 91.4%, and 90.3%, respectively. The specificity at 24 h was 85.3%, 97.1%, 98.0%, and 98.0%, while that at 48 h was 79.4%, 85.3%, 95.2%, and 95.1%, respectively. The specificity of chromogenic media at 24 h and 48 h was significantly higher than that of EB. Furthermore, the specificity at 48 h was significantly higher for chromID VRE and VRESelect than Brilliance VRE, although color distinction was easier with VRESelect. CONCLUSION: Based on our results, use of chromID VRE or VRESelect is more reliable and convenient for screening of VRE. In addition, five vanA-positive Enterococcus gallinarum, Enterococcus avium and Enterococcus durans were isolated, and two of them (one E. avium and one E. durans) were detected only on VRESelect.

Vancomycin resistant Enterococcus spp (VRE): follow up during 9 years in a tertiary teaching hospital in southern Brazil

Introduction: Infection with vancomycin-resistant Enterococcus spp (VRE) has been a worldwide problem since mid 1980’s and, in Brazil, since 1996. This study was conducted to evaluate the experience with VRE in our institution. Methods: A prospective cohort study from 2000 to 2009 was conducted at Hospital São Lucas da PUCRS. All hospitalized patients with VRE positive culture were included and followed from their diagnosis until they were negative for VRE or their discharge. Only the first admission for each VRE positive patient was included. Pulsed field gel electrophoresis (PFGE) was performed to determine how VRE had spread. Results: A total of 315 cases of VRE were identified, 224 of which were isolated from rectal swabs. Vancomycin-resistant/ampicilin susceptible Enterococcus faecalis were identified in 312 isolates. PFGE was performed in 47 VRE isolates that presented an indistinguishable migratory profile. The median length of hospital stay and length of stay before VRE isolation were 46 days and 21 days, respectively; 52% of the patients were aged 60 and above. The annual distribution of the new VRE cases showed a clear decrease from 2000 to 2009. Discussion: This study shows a substantial VRE colonization (71%) with a homogenous pattern that emphasizes its transversal spread. Predominance of E. faecalis differs from the literature which largely describes a higher prevalence of vancomycin-resistant Enterococcus faecium. The follow up of VRE during 9 years in our institution highlighted the importance of continuous surveillance to prevent outbreaks in our hospital.

Prevalence and antimicrobial resistance pattern of multidrug-resistant enterococci isolated from clinical specimens.

Purpose: Vancomycin-resistant enterococci (VRE) pose an emerging problem in hospitals worldwide. The present study was undertaken to determine the occurrence, species prevalence, antibacterial resistance, and phenotypic and genetic characteristics of VRE isolated in Riyadh hospitals, KSA. Materials and Methods: Two hundred and six isolates of enterococcal species were obtained from clinical samples. The antibiotic susceptibility of isolates and minimum inhibitory concentration (MIC) tests for vancomycin and teicoplanin were determined. Molecular typing of VRE isolates was carried out by using pulsed field gel electrophoresis (PFGE) and the resistance genotype was determined by polymerase chain reaction (PCR). Results: VRE accounted for 3.9% of the isolates and were detected mostly in urine, wound and blood specimens isolated from ICU, internal medicine and surgical wards. All strains were identified to species level and were found to consist of E. faecalis (69.2%), E. faecium (11.3%), E. avium (2.1%), E. hirae (0.8%), E. casseliflavus (1.3%) and E. gallinarum (1.3%) species. According to the susceptibility data obtained, 8 (3.9%) out of 206 isolates were found to be VRE (MICs > 32 μg/ml). The vanA, vanB and vanC gene fragments of E. faecalis, E. faecium and E. gallinarum were amplified from isolates and were detected. PFGE patterns of the VRE isolates revealed homogenous patterns with dominant clone suggesting that the strains intrinsic resistance is independent. Conclusions: This study shows an emergence of VRE along with increased rate of multidrug-resistant enterococci in the area of the study. Regular surveillance of antimicrobial susceptibilities should be done regularly and the risk factors should be determined.

Characterization of vancomycin resistant Enterococcus faecium from clinical and chicken sources

Objective: The study was undertaken to investigate the genomic and phenotypic relationship among E.faecium strains isolated from chicken and clinical sources. Methods: Enterococci were isolated and identified by conventional biochemical methods and the antibiotic susceptibility was determined by disk diffusion methods. Phenotypes and genotypes of vancomycin resistance were detected by E tests and PCR amplification techniques respectively. Genotyping of the vancomycin resistant E.faecium from two sources were done by RAPD typing. Results: The Vancomycin resistant E.faecium identified was selected for this comparative study. Among the VREF from two sources minor biochemical difference with regards to raffinose fermentation and haemolytic properties was observed. The RAPD tests using random primers also showed polymorphism. Conclusion: The results of the study showed that the strains from two different sources were not identical.

Antimicrobial activity of essential oils against Vancomycin-Resistant enterococci (VRE) and Escherichia coli O157: H7 in feta soft cheese and minced beef meat

Eleven essential oils (EOs) were evaluated for their antibacterial properties, against Vancomycin-Resistant Enterococci (VRE) and E. coli O157:H7. EOs were introduced into Brain Heart Infusion agar (BHI) (15ml) at a concentration of 0.25 to 2 percent (vol/vol) to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for each pathogen evaluated. Results showed that the most active essential oils against bacteria tested were thyme oil, with MIC90 and MBC90 for the VRA strains of 0.25 percent and 0.5 percent, respectively. Eucalyptus, juniper and clove oils were the least potent agent, with MIC90 and MBC90 of 2 percent. Furthermore, the inhibitory effect of these EO were evaluated against VRE and E. coli O157:H7, experimentally inoculated (10³ cfu/g) in Feta soft cheese and minced beef meat, which was mixed with different concentrations (0.1 percent, 0.5 percent and 1 percent) of the EO and stored at 7 ºC for 14 days. Out of eucalyptus, juniper, mint, rosemary, sage, clove and thyme oils tested against target bacteria sage and thyme showed the best results. Clove and mint did not show any effect on VRE and E. coli O157:H7 in both kinds of studied foods. The addition of thyme oil at concentrations of 0.5 and 1 percent caused best significant reduction in the growth rate of VRE and E. coli O157:H7 in cheese and meat at 7 ºC. It is concluded that selected plant EOs can act as potent inhibitors of both microorganisms in a food product. The results revealed the potential of thyme oil as a natural preservative in feta soft cheese and minced beef meat against VRE and E. coli O157:H7 contamination.

Risk Factors for Recurrence of Clostridium difficile Infection: Effect of Vancomycin-resistant Enterococci Colonization

Recurrent Clostridium difficile infection (CDI) is one of the most difficult problems in healthcare infection control. We evaluated the risk factors associated with recurrence in patients with CDI. A retrospective cohort study of 84 patients with CDI from December 2008 through October 2010 was performed at Pusan National University Yangsan Hospital. Recurrence occurred in 13.1% (11/84) of the cases and in-hospital mortality rate was 7.1% (6/84). Stool colonization with vancomycin-resistant enterococci (VRE) (P = 0.006), exposure to more than 3 antibiotics (P = 0.009), low hemoglobin levels (P = 0.025) and continued use of previous antibiotics (P = 0.05) were found to be more frequent in the recurrent group. Multivariate analysis indicated that, stool VRE colonization was independently associated with CDI recurrence (odds ratio, 14.519; 95% confidence interval, 1.157-182.229; P = 0.038). This result suggests that stool VRE colonization is a significant risk factor for CDI recurrence.

Antimicrobial Resistance of Enterococcal Isolates from Blood and Risk Factors for Vancomycin Resistant Enterococcal Bacteremia in a Tertiary Care University Hospital from 2003 to 2007 / 대한임상미생물학회지

BACKGROUND: In Korea, a sudden increase in vancomycin-resistant enterococci (VRE) infection has been noted since the late 1990s. This study was conducted to describe the antimicrobial resistances of enterococcal blood isolates and to identify risk factors associated with VRE bacteremia in a tertiary care university hospital over a recent five-year period. METHODS: This study was conducted to analyze the antimicrobial susceptibilities of enterococcal blood isolates by year from January 2003 to December 2007. Multivariate logistic regression analysis was used to investigate factors associated with VRE bacteremia. RESULTS: A total of 225 enterococcal strains (44.7% Enterococcus faecalis, 42.4% Enterococcus facium, 5.9% Enterococcus casseliflavus, and 4.7% Enterococcus gallinarum) were detected in blood, 55 of which (21.6%) were resistant to vancomycin. In 2004 and 2005, the resistance rates for vancomycin and teicoplanin (33.3% and 27.3%; 34.4% and 23.0%, respectively) increased. In 2003, 2006, and 2007, the resistance rates for vancomycin and teicoplanin (8.7% and 8.7%; 19.0% and 14.3%; 13.5% and 11.5%, respectively) decreased relative to those of the previous years. When 55 patients with VRE bacteremia were compared with 55 patients with vancomycin-susceptible enterococcal bacteremia using multivariate analysis, E. faecium bacteremia (OR 12.624, P<0.001) and enterococcal bacteremia caused by species other than E. faecium and E. faecalis (OR 21.473, P=0.011) were found to be statistical risk factors. Among several infection control activities, the restricted uses of vancomycin and quinupristin-dalfopristin decreased the vancomycin resistance rate from 27.78% to 15.50% (P=0.0257). CONCLUSION: VRE bacteremia would be effectively controlled via infection control activities based on studies regarding risk factors associated with VRE bacteremia.

Characterization of Vancomycin-Resistant Enterococci Isolated from Stools and Their Acquisition of Vancomycin Resistance

We have isolated 6 vancomycin resistant (VR) Enterococcus faecium and 5 VR-E. gallinarum. Vancomycin resistant enterococcus (VRE) isolates were resistant to multi-drugs, but susceptible to linezolid and quinupristin/dalfopristin. VRE isolates showed 10 VanA phenotypes and 1 VanB phenotype (E. gallinarum). However, all of them showed vanA genotype. vanA gene was detected on both genomic and plasmid DNA from all VRE isolates. Almost of VR-E. faecium had IS1216V which is worldwide type and almost of VR-E. gallinarum had IS1542 which is European type. IS1216V and IS1542 genes were not related with antibiotic types of VRE. Copy numbers of vanA were decreased in VRE with IS1216V or IS1542 but not in VRE with both ISs in broth without vancomycin. The copy numbers of vanA were significantly decreased in VanB phenotype of VRE with IS1542 in broth without vancomycin. Copy numbers of vanA were recovered in the presence of vancomycin. Growth time of reference E. faecium is faster than that of reference E. faecalis when cultured in the broth containing vancomycin. Reference strains cultured in the broth containing vancomycin showed intermediate resistance or resistance to antibiotics without acquisition of van genes. Naturally, multidrug-resistant E. faecium might be fast adapted in the presence of vancomycin compared to E. faecalis. Taken together, VanA phenotype E. gallinarum as well as E. feacium have been increasing in nosocomial infection and showed acquired inducible resistance. E. faecium and E. faecalis showed intermediate resistance in long exposure of vancomycin without acquisition of vanA.

Evaluation of the Usefulness of Selective Chromogenic Agar Medium (ChromID VRE) and Multiplex PCR Method for the Detection of Vancomycin-resistant Enterococci / 대한진단검사의학회지

BACKGROUND: Accurate and early detection of vancomycin-resistant enterococci (VRE) is critical for controlling nosocomial infection. In this study, we evaluated the usefulness of a selective chromogenic agar medium and of multiplex PCR for detection of VRE, and both these techniques were compared with the conventional culture method for VRE detection. METHODS: We performed the following 3 methods for detecting VRE infection in stool specimens: the routine culture method, culturing in selective chromogenic agar medium (chromID VRE, bioMerieux, France), and multiplex PCR using the Seeplex(R) VRE ACE Detection kit (Seegene Inc., Korea) with additional PCR for vanC genes. RESULTS: We isolated 109 VRE strains from 100 stool specimens by the routine culture method. In chromID VRE, all the isolates showed purple colonies, including Enterococcus gallinarum and E. raffinosus, which were later identified using the Vitek card. All VRE isolates were identified by the multiplex PCR method; 100 were vanA-positive E. faecium, 8 were vanA- and vanC-1-positive E. gallinarum, and 1 was vanA-positive E. raffinosus. CONCLUSIONS: For VRE surveillance, culturing the isolates in chromID VRE after broth enrichment appears to be an accurate, rapid, and easy method for routine screening test. Multiplex PCR is relatively expensive and needs skilled techniques for detecting VRE, but it can be an auxiliary tool for rapid detection of genotype during a VRE outbreak.

Rapid detection of Vancomycin-Resistant Enterococci (VRE) in rectal samples from patients admitted to intensive care units

The reduction in time required to identify vancomycin-resistant enterococci (VRE) has gained increased importance during hospital outbreaks. In the present study, we implemented a laboratory protocol to speed up the VRE screening from rectal samples. The protocol combines a medium for selective VRE isolation (VREBAC®, Probac, São Paulo) and a multiplex PCR for detection and identification of vanA and vanB resistance genes. The screening performance was analyzed in 114 specimens collected from four intensive care units. The swabs were collected at two periods: (1) during a VRE outbreak (February 2006, n=83 patients) and (2) at the post-outbreak period, after adoption of infection control measures (June 2006, n=31 patients). Forty-one/83 VRE (49.4 percent) and 3/31(9.7 percent) VRE were found at the first and second period, respectively. All isolates harbored the vanA gene. In both periods, detection of the gene vanA parallels to the minimum inhibitory concentration values of >256 µg/mL and >48 µg/mL for vancomycin and teicoplanin, respectively. Multiplex PCR and conventional methods agreed in 90.2 percent for enterococci identification. Besides this accuracy, we also found a remarkable reduction in time to obtain results. Detection of enterococcal species and identification of vancomycin resistance genes were ready in 29.5 hours, in comparison to 72 hours needed by the conventional methods. In conclusion, our protocol identified properly and rapidly enterococci species and vancomycin-resistance genes. The results strongly encourage its adoption by microbiology laboratories for VRE screenning in rectal samples.

In vitro fosfomycin activity in vancomycin-resistant Enterococcus faecalis

Enterococci are part of the endogenous flora of human beings, are naturally resistant to several classes of antimicrobials, and are able to acquire resistance with relative ease. Currently the vancomycin-resistant enterococci are spread all over the world and treatment options for infections caused by it are often extremely limited. We assessed 193 vancomycin-resistant Enterococcus faecalis isolates collected from four different hospitals in Porto Alegre for their susceptibility to fosfomycin using the E-test and agar diffusion. Fosfomycin proved to be active in vitro against the great majority of isolates, indicating that it is a valid option in the treatment of these infections.