Molecular epidemiology of vancomycin-resistant enterococci from 6 hospitals in New York State.

BACKGROUND: Vancomycin resistance among enterococci is an emerging nosocomial problem. Consequently, it is important to understand the distribution of vancomycin-resistant enterococci (VRE) within and between hospitals to implement appropriate infection control measures. METHODS: In this study, 116 VRE isolates obtained from patients in 6 New York State hospitals were analyzed by antibiotic susceptibility testing, pulsed-field gel electrophoresis (PFGE) fingerprinting, plasmid profile analysis, vanA and vanB polymerase chain reaction, and DNA:DNA hybridization with vanA and vanB probes. RESULTS: PFGE and plasmid typing generally agreed, but plasmid profiles were more variable. These analyses revealed that genetic heterogeneity among isolates from within each of the 6 hospitals varied considerably. Among 23 Enterococcus faecium isolates from one hospital, there were only 3 PFGE types, and 20 isolates had the same type. However, in another hospital, each isolate was genetically distinct. Closely related strains were not found in separate hospitals. VRE strains with vanA genes and strains with vanB genes were found in 3 hospitals. Both plasmid and chromosomal carriage of these genes was detected. CONCLUSIONS: PFGE typing showed that nosocomial VRE transmission had occurred in some hospitals. However, there was no evidence for it in others. Neither was there evidence for intrahospital transmission or for emergence of an endemic strain. These observations demonstrate that it is important to evaluate genetic heterogeneity among VRE before implementation of infection control measures. PFGE is the method of choice for epidemiologic typing, but polymerase chain reaction, plasmid, and hybridization studies can provide important information concerning the presence and potential for transfer of vancomycin resistance genes.     

Enterococcus faecium resistente a glucopéptidos. Análisis del genotipo de resistencia,virulencia y líneas genéticas

Objective

The objective of this study was to analyse the genotypic characteristics of all Enterococcus isolates with acquired vancomycin resistance (VRE) recovered in the Hospital Clinic (Barcelona, Spain) in a period of three years and two months.

Methods

All VRE isolated in the referred Hospital in the period January 2004-March 2007 were included in the study. The vancomycin resistance mechanism was investigated, as well as other antibiotic resistance mechanisms. Isolates were also typed by pulsed-field-gel-electrophoresis (PFGE) and multi-locus-sequence-typing (MLST).

Results

Thirty-nine VRE were recovered, all being identified as E. faecium, representing 2% of total enterococci obtained in that period. Thirty-eight of them carried the vanA gene, and one isolate the vanB2 gene. The 39 VRE were classified into 13 different pulsotypes (A-M), with one main pulsotype, A, which included 13 isolates. The sequence type was identified by MLST in 24 VRE (with unrelated or closely-related PFGE patterns), and they were ascribed to the clonal complex CC17, but two classified as CC9. All VRE showed a multiresistance phenotype, including, in most cases ampicillin, ciprofloxacin, erythromycin, streptomycin, gentamicin, kanamycin and chloramphenicol, harbouring multiple antibiotic resistance genes. The presence of esp and/or hyl genes was identified in 37 VRE.

Conclusion

All VRE, but one, showed the vanA genotype and they were mostly ascribed to the high-risk clonal complex CC17.     

Vancomycin-resistant enterococci among haemodialysis patients in Portugal: Prevalence and molecular characterization of resistance,virulence and clonality

Introduction

Vancomycin-resistant enterococci (VRE) among haemodialysis patients has increased rapidly and, to date, there is no report of this incidence in Portugal.

Methods

A total of 121 faecal samples were collected from haemodialysis patients, and then tested for VRE. Antimicrobial resistance, virulence and multilocus sequence typing (MLST) were studied.

Results

VRE prevalence was 3.3%. Three VRE isolates, Enterococcus faecium, Enterococcus faecalis and Enterococcus raffinosus, were multi-resistant and vanA-positive. E. faecium and E. faecalis belonged to CC17 and CC2, respectively.

Conclusion

Haemodialysis patients in Portugal are colonized with virulent, multi-resistant enterococci from high-risk clonal complexes, representing a public health concern.     

Healthcare-associated risk factors of vancomycin-resistant Enterococci colonization among outpatients undergoing hemodialysis

Stool specimens and data were obtained from 399 outpatients undergoing hemodialysis (HD) in order to estimate the colonization rate of vancomycin-resistant enterococci (VRE) and to determine risk factors for VRE acquisition. The prevalence of VRE colonization in outpatients ranged from 0%-22.2%. Risk factors associated with VRE colonization were high hierarchy of hospital, short duration of HD, recent hospitalization, prior use of antimicrobial products, high platelet count, and low hemoglobin/albumin/blood urea nitrogen/creatinine levels, showing that VRE colonization was more common in patients with prior infections and poor nutritional status. Although pulsed-field gel electrophoresis (PFGE) analysis showed that most VRE isolates had diverse patterns, 2 paired cases from separate hospitals presented identical PFGE types.     

Low faecal carrier rate of vancomycin resistant enterococci in Norwegian hospital patients

The faecal carrier rate of vancomycin resistant enterococci (VRE) was surveyed among 616 patients in selected departments of 7 Norwegian hospitals. One Enterococcus gallinarum isolate harbouring a vanB2 element was recovered from a child with malignant disease treated with vancomycin and ceftazidime. No vancomycin resistant Enterococcus faecalis or Enterococcus faecium were detected and no VRE isolates of the VanA type were identified. The low level of VRE carriage corresponds to the limited use of glycopeptide antibiotics for human therapeutic purposes in Norway. It indicates a low risk of acquiring VRE infections in Norwegian hospitals.     

Typing of Vancomycin-Resistant <Emphasis Type="Italic">Enterococcus faecium</Emphasis> Strains in a Cohort of Patients in an Italian Intensive Care Unit

Abstract Background: Vancomycin-resistant enterococci (VRE) have become a major cause of nosocomial infections. The increase of vancomycin-resistant Enterococcus faecium (VR-Efm) in an intensive care unit (ICU) of an Italian university hospital from 2003 through 2004, led us to evaluate the phenotypic and genetic features of these strains. The prevalence of different bacterial species in this ICU is described. The antibiotic resistance profiles of VR-Efm strains, their van-genotype and pulsed-field gel electrophoresis (PFGE) profiles were also analyzed. Materials and Methods: From January 2003 to December 2004, VR-Efm strains were collected from several biological samples. Bacteria were identified using standard biochemical reactions and automated systems. Antibiotic susceptibility was evaluated by disk diffusion and microdilution methods. Resistance to glycopeptides was confirmed by the E test. Vancomycin-resistant genotypes (vanA, vanB) were identified by PCR. Strains were typed by PFGE. Results: Fifty E. faecium strains were isolated from a total of 700 patients. Of these, 26 were vancomycin-resistant and were isolated from 26 different patients. We also found one strain with resistance to linezolid. The vanA genotype was identified in 20/26 strains and vanB in the remaining strains. A major pulsed-field cluster (“A”) was identified. In this cluster, 14 strains were identified (A1–A14) and 25 out of 26 VR-Efm belonged to it. Only one strain showed a different pattern (strain type “B”). All isolates with the vanA genotype belonged to cluster “A”, therefore five out of six isolates with the vanB genotype belonged to cluster A. The only strain with type B pattern was the vanB genotype. Conclusions: Isolation of VR-Efm was very frequent (52%) in our cohort of patients and the vanA genotype was the most frequent (77%). We found 25 out of 26 VR-E. faecium strains to be epidemiologically related by PFGE (cluster A). Strains with distinct genotypes shared closely related PFGE profiles. The occurrence of one major cluster among patients of a single unit indicated intra-facility VRE transmission.     

Epidemiological study on vancomycin-resistant enterococci from fecal samples in the east area of Japan

Recently, Vancomycin-resistant enterococci (VRE) have become important nosocomial pathogens in the world. In Japan, the VRE-infection was first reported in 1996. However, an epidemiological study on VRE has not been aggressively done in Japan. We conducted a survey study to explore the incidence and antimicrobial susceptibility of vancomycin-resistant enterococci isolated from fecal samples at 45 hospitals in the east area of Japan (Kanto, Koshinetsu, Tohoku, and Hokkaido) during June 1998 to March 1999. The Enterococcosel agar containing vanocomycin (BBL) was used for screening VRE from fecal samples in each hospital. The susceptibilities of the isolates to 8 antimicrobials were determined by the broth microdilution method and the definitions of resistance were based on current standards of the NCCLS standards. The VRE genotypes (vanA, vanB, vanC1, and van C2/3) were confirmed by amplifying the respective genes by PCR. Eight hundred and ninety four strains of enterococci were tested by the microtiter plates hybridization method (WAKUNAGA SEIYAKU, Japan). One thousand five hundred eighty three strains of enterococci were collected from 6,914 patients in 45 hospitals. These strains included 72 (4.5%) strains Enterococcus faecalis, 33 (2.1%) strains Enterococcus faecium, 17 (1.1%) strains Enterococcus avium, 1,040 (65.7%) strains Enterococcus gallinarum, 386 (24.4%) strains Enterococcus cassliflavus, and 35 (2.2%) strains Enterococcus flavescens. These strains of vancomycin-resistant E. faecalis were isolated from 3 patients, two of these 3 strains had van A gene and other one had van B gene. Those 3 strains were in the Kanto area, and 2 of 3 strains were in Tokyo, Generally, though van A type VRE was highly resistaant to both vancomycin and teicoplanin. In our study, two strains of van A type E. faecalis were highly resistant to vancomycin (MICs > 128 micrograms/ml) and susceptible to teicoplanin with MICs 4 micrograms/ml. Those two strains were different in susceptibilities of minocycline and ofloxacin. The result of the analysis of PFGE had also different patterns. VanB type E. fecalis was highly resistant to vancomycin and susceptible to teicoplanin (MICs 0.25 microgram/ml). For ampicillin and imipenem, 3 strains of E. faecalis were susceptible (MIC < or = 1 microgram/ml). One of 562 strains of E. gallinarum had vanB and vanC1 genes and was moderately resistant to vancomycin and susceptible to teicoplanin. All strains of E. casseliflavus and E. flavescens had vanC2/C3 gene only. All strains of E. faecium and E. avium did not detect van genes. From this result, it was supposed that VRE were very rare in the east of Japan.     

Low prevalence of VRE gastrointestinal colonization of hospitalized patients in Manitoba tertiary care and community hospitals

OBJECTIVE:

To determine the prevalence of vancomycin-resistant enterococci (VRE) bowel colonization in hospitalized patients in Manitoba who had stool specimens collected for Clostridium difficile toxin and/or culture testing.

DESIGN:

Two tertiary care and five community hospitals in Winnipeg and three rural Manitoba community hospitals participated in this study. From January 1 to December 31, 1997 stool specimens, one per patient, submitted to hospital microbiology laboratories for C difficile toxin and/or culture testing were screened for VRE on colistin-nalidixic acid-vancomycin (6 μg/mL) (CNAV) agar plates. The study was divided into six, eight-week intervals. Stool specimens received in the first two weeks of each eight week interval were screened for VRE.

MAIN RESULTS:

A total of 1408 stool specimens were submitted over the 48-week study period. Sixty-seven (4.8%) patients with VRE colonization of their lower gastrointestinal tract were identified. Three of the 67 (4.5%) VRE isolates were Enterococcus faecium, with the remaining 64 (95.5%) were Enterococcus gallinarum. The three vancomycin-resistant E faecium -VREF- (from two different Winnipeg hospitals) demonstrated the vanA genotype, and were resistant to vancomycin, teicoplanin and ampicillin. All three VREF isolates also demonstrated high level resistance to both gentamicin and streptomycin but were susceptible to quinuprisitin/dalfopristin and {"type":"entrez-nucleotide","attrs":{"text":"LY333328","term_id":"1257359838"}}LY333328.

CONCLUSION:

VRE colonization in hospitalized patients in Manitoba is infrequent and most commonly due to E gallinarum. The prevalence of VREF colonization in the patients studied was 0.2% (three of 1408).Key Words: Manitoba, Prevalence, Vancomycin-resistant enterococciVancomycin-resistant Enterococcus faecium (VREF) accounts for up to 65% of E faecium isolates in hospitalized patients across the United States and is endemic in many North American tertiary care institutions (1,2). The management of these infections presents a significant clinical challenge because species of the genus Enterococcus, and in particular E faecium, are frequently resistant to several antimicrobial agents (3). High level penicillin resistance, high level aminoglycoside resistance and most recently vancomycin resistance are emerging as significant concerns in the treatment of enterococcal infections. This has prompted the development and evaluation of new antimicrobial agents such as quinupristin/dalfopristin and {"type":"entrez-nucleotide","attrs":{"text":"LY333328","term_id":"1257359838"}}LY333328, a glycopeptide, which may offer activity against enterococci resistant to conventional therapy (2).VREF is not endemic in Manitoba hospitals, and infection with VREF is extremely rare (4). However, the prevalence of VREF lower gastrointestinal tract (GIT) carriage, which frequently precedes infection (5,6), is presently unknown for patients hospitalized in Manitoba. To determine whether the lack of VREF endemnicity correlated with an absence of lower GIT colonization, we assessed lower GIT carriage of VREF for patients hospitalized in 10 Manitoba hospitals from January 1 to December 31, 1997. Our study was consistent with Centers for Disease Control and Prevention guidelines (Atlanta, Georgia) that suggest surveillance programs for vancomycin-resistant enterococci (VRE) be undertaken on an intermittent basis in areas where VRE is not known to be endemic (6). Isolates of VREF identified were phenotypically and genotypically characterized, and tested for their susceptibilities against a panel of antimicrobial agents.     

COMPARISON BETWEEN AUTOMATED SYSTEM AND PCR-BASED METHOD FOR IDENTIFICATION AND ANTIMICROBIAL SUSCEPTIBILITY PROFILE OF CLINICAL Enterococcus spp

Enterococci are increasingly responsible for nosocomial infections worldwide. This study was undertaken to compare the identification and susceptibility profile using an automated MicrosScan system, PCR-based assay and disk diffusion assay of Enterococcus spp. We evaluated 30 clinical isolates of Enterococcus spp. Isolates were identified by MicrosScan system and PCR-based assay. The detection of antibiotic resistance genes (vancomycin, gentamicin, tetracycline and erythromycin) was also determined by PCR. Antimicrobial susceptibilities to vancomycin (30 µg), gentamicin (120 µg), tetracycline (30 µg) and erythromycin (15 µg) were tested by the automated system and disk diffusion method, and were interpreted according to the criteria recommended in CLSI guidelines. Concerning Enterococcus identification the general agreement between data obtained by the PCR method and by the automatic system was 90.0% (27/30). For all isolates of E. faecium and E. faecalis we observed 100% agreement. Resistance frequencies were higher in E. faecium than E. faecalis. The resistance rates obtained were higher for erythromycin (86.7%), vancomycin (80.0%), tetracycline (43.35) and gentamicin (33.3%). The correlation between disk diffusion and automation revealed an agreement for the majority of the antibiotics with category agreement rates of > 80%. The PCR-based assay, the van(A) gene was detected in 100% of vancomycin resistant enterococci. This assay is simple to conduct and reliable in the identification of clinically relevant enterococci. The data obtained reinforced the need for an improvement of the automated system to identify some enterococci.     

Analysis of three phenotyping methods and pulsed-field gel electrophoresis for differentiation of methicillin resistant Staphylococcus aureus isolated from two hospitals in Thailand

Methicillin resistant Staphylococcus aureus (MRSA) is an important hospital and community-acquired pathogen. Rapid and reliable epidemiologic typing is necessary for controlling the spread of MRSA outbreak. The objective of this study was to compare the phenotyping with the genotyping method to differentiate MRSA isolates obtained from the two hospitals in Thailand (central and northeastern). Seventy-four MRSA isolates were randomly collected and confirmed by the presence of mecA gene. Antibiogram, phage typing and enterotoxin production were used for the phenotyping analysis. Pulsed-field gel electrophoresis (PFGE) with Smal digestion of chromosomal DNA was used for the genotyping analysis. We found 17 distinct profiles by the 3 phenotypic typing methods and 18 PFGE types designated as 5 major types (A-E) and 13 subtypes. The most frequent PFGE types and their related subtypes found in both hospitals were A and C, comprising 54 and 27%, respectively. The antibiogram could differentiate 6 different types. All isolates were resistant to the majority of antimicrobial agents tested, but were susceptible to vancomycin and fosfomycin. Ten (13.5%) MRSA isolates produced enterotoxin A. Nontypable phage and phage type 77 were found predominantly in MRSA isolated from the northeast and central hospital, respectively. A significant correlation was found between the phenotyping and the genotyping methods and there was a good correlation between antibiogram and PFGE. Antibiogram typing alone can be used as a useful epidemiological marker for practical purposes. PFGE types A and C were the common endemic MRSA clones in both hospitals in Thailand.     

Toxin-antitoxin systems are ubiquitous and plasmid-encoded in vancomycin-resistant enterococci

Vancomycin-resistant enterococci (VRE) are common hospital pathogens that are resistant to most major classes of antibiotics. The incidence of VRE is increasing rapidly, to the point where over one-quarter of enterococcal infections in intensive care units are now resistant to vancomycin. The exact mechanism by which VRE maintains its plasmid-encoded resistance genes is ill-defined, and novel targets for the treatment of VRE are lacking. In an effort to identify novel protein targets for the treatment of VRE infections, we probed the plasmids obtained from 75 VRE isolates for the presence of toxin-antitoxin (TA) gene systems. Remarkably, genes for one particular TA pair, the mazEF system (originally identified on the Escherichia coli chromosome), were present on plasmids from 75/75 (100%) of the isolates. Furthermore, mazEF was on the same plasmid as vanA in the vast majority of cases (>90%). Plasmid stability tests and RT-PCR raise the possibility that this plasmid-encoded mazEF is indeed functional in enterococci. Given this ubiquity of mazEF in VRE and the deleterious activity of the MazF toxin, disruption of mazEF with pharmacological agents is an attractive strategy for tailored antimicrobial therapy.     

Impact of the reduction of environmental and equipment contamination on vancomycin-resistant enterococcus rates

More than 1,500 perirectal swab cultures and 552 environmental and equipment cultures were collected during the study period. Enterococcus faecium was the most frequent species isolated, being responsible for 71% of the positive cultures. Fifty infections were documented, with bloodstream infections (18, 36%) being the most frequent, followed by urinary tract infection (15, 30%). An educational intervention was given to 136 healthcare workers (HCWs), and a questionnaire regarding vancomycin-resistant enterococcus (VRE) transmission was also performed pre- and post-intervention. Overall, 858 opportunities of patient care were evaluated. The compliance with contact precautions did not improve; however, in general, the proportion of correct answers regarding VRE increased significantly when comparing pre- and post-intervention periods (p < 0.05). On the other hand, the proportion of environmental and equipment contaminated by VRE decreased significantly from pre- (23.2%) to post-intervention (8.2%) (p < 0.001) and was associated with a significant decrease in VRE infection from 7.7 to 1.9 when comparing the pre- and post-intervention periods. The use of vancomycin (defined daily dose [DDD]) did not change significantly over the study period (p = 0.970), and the use of teicoplanin increased (p < 0.001). Seventy-six percent of E. faecium belong to type and subtype A by pulsed-field gel electrophoresis (PFGE). This predominant type was found in the environment and caused colonization and infection. In conclusion, the present study showed that reduction of the proportion of environmental and equipment contamination was associated with a decrease of colonization and infection due to VRE, and that the strategy to control VRE dissemination should be based on local problems.     

Infecciones causadas por bacterias grampositivas multirresistentes (Staphylococcus aureus y Enterococcus spp.)

Methicillin -resistant Staphylocccus aureus (MRSA) and multirresistant entorococci are still problematic in nosocomial infections and new challenges have emerged for their containment. MRSA has increased the multiresistant profile; it has been described vancomycin and linezolid resistant isolates and isolates with decreased daptomycin susceptibility. Moreover, new clones (ST398) have emerged, initially associated with piggeries, and new mec variants (mecC) with livestock origin that escape to the detection with current molecular methods based on mecA gene have been detected. In enterococci, linzeolid resistant isolates and isolates with deceased susceptibility to daptomycin have been described. Moreover, ampicillin resistant Enterococcus faecium due to β-lactamase production has been recently found in Europe. Control of MRSA isolates and multiresistant enteroccocci should combined antibiotic stewardship strategies and epidemiological measures, including detection of colonized patients in order to reduce colonization pressure and their transmission.     

Epidemiology and molecular characterization of vancomycin resistant Enterococci isolates in India

Little attention has been paid to the problem of the spread of vancomycin resistant enterococci (VRE) in India. Between August 2002 to March 2003, faecal and urine samples of patients from various wards of the Postgraduate Institute of Medical Education and Research, Chandigarh, India, were screened for vancomycin resistance. 36 VRE were isolated (18 Enterococcus gallinarum, 9 E. casseliflavus, 7 E. faecium and 2 E. faecalis). These isolates were characterized as low-, moderate- and high-level resistant strains by phenotypic as well as genotypic methods such as minimum inhibitory concentration determination, polymerase chain reaction assays, sequencing of PCR products and multiple sequence alignment of van genes. Correlations established between these results and the vancomycin resistance markers were designated as vanA (783 bp), vanB (635 bp), vanC1 (822 bp) and vanC2 (484 bp) according to the findings of earlier workers as well as comparison with existing databases. Prolonged hospital stay and vancomycin were important risk factors for both VRE UTI and colonization. Renal dialysis, renal failure, prior aminoglycoside and third generation cephalosporin were the other significant factors for VRE UTI. The study also highlights the importance of screening for VRE in clinical samples and recommends the institution of control measures to prevent the further spread of VRE.     

Reporting antimicrobial susceptibilities and phenotypes of resistance to vancomycin in vancomycin-resistant Enterococcus spp. clinical isolates: A nationwide proficiency study

IntroductionThe ability of Spanish microbiology laboratories to (a) determine antimicrobial susceptibility (AS), and (b) correctly detect the vancomycin resistance (VR) phenotype in vancomycin-resistant Enterococcus spp. (VRE) was evaluated.MethodsThree VRE isolates representing the VanA (E. faecium), VanB (E. faecium) and VanC (E. gallinarum) VR phenotypes were sent to 52 laboratories, which were asked for: (a) AS method used; (b) MICs of ampicillin, imipenem, vancomycin, teicoplanin, linezolid, daptomycin, ciprofloxacin, levofloxacin and quinupristin–dalfopristin, and high-level resistance to gentamicin and streptomycin; (c) VR phenotype.Results(a) The most frequently used system was MicroScan; (b) according to the system, the highest percentage of discrepant MICs was found with gradient strips (21.3%). By antimicrobial, the highest rates of discrepant MICs ranged 16.7% (imipenem) to 0.7% (linezolid). No discrepant MICs were obtained with daptomycin or levofloxacin. Mayor errors (MEs) occurred with linezolid (1.1%/EUCAST) and ciprofloxacin (5.0%/CLSI), and very major errors (VMEs) with vancomycin (27.1%/EUCAST and 33.3%/CLSI) and teicoplanin (5.7%/EUCAST and 2.3%/CLSI). For linezolid, ciprofloxacin, and vancomycin, discrepant MICs were responsible for these errors, while for teicoplanin, errors were due to a misassignment of the clinical category. An unacceptable high percentage of VMEs was obtained using gradient strips (14.8%), especially with vancomycin, teicoplanin and daptomycin; (c) 86.4% of the centers identified VanA and VanB phenotypes correctly, and 95.0% the VanC phenotype.ConclusionMost Spanish microbiology laboratories can reliably determine AS in VRE, but there is a significant percentage of inadequate interpretations (warning of false susceptibility) for teicoplanin in isolates with the VanB phenotype.     

ESBL-producing-multidrug resistant E. coli population from urinary tract infections is less diverse than non-ESBL-multidrug resistant population

ObjectiveThe aim of this study was to compare the population structure of three different representative groups of E. coli isolates causing urinary tract infections in a large area of Madrid, Spain: two groups of multidrug resistant isolates (MDR), ESBL- and non-ESBL producers, and one of fully-susceptible isolates (35 isolates in each group).MethodsEpidemiological relatedness was studied by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). The presence of genes encoding ESBL was determined by using PCR and sequencing. Antimicrobial susceptibility testing was performed by broth microdilution.ResultsPFGE analysis revealed a high degree of genetic diversity in susceptible and non-ESBL-MDR groups. However, the ESBL-MDR E. coli population was less diverse and a large cluster consisting of ST131 and CTX-M-15-producing isolates was detected.ConclusionsThe present study revealed that ESBL-producing-MDR E. coli population was less diverse than the non-ESBL MDR group and that ST131 was dominant among CTX-M-15-producing isolates that reflects the spread of this successful MDR lineage.     

In Vitro Activity of LY333328, a New Glycopeptide, against Extracellular and Intracellular Vancomycin-Resistant Enterococci

Summary The objectives of the study were to observe the activity of LY333328, a new semisynthetic glycopeptide, compared to that of vancomycin against six strains of Enterococcus faecium and Enterococcus faecalis, including four vancomycin-resistant strains. Bacteria ingested by polymorphonuclear leukocytes (PMN) as well as extracellular bacteria were studied using a colony count method. The activity against intracellular bacteria was tested with the drugs present in the extracellular medium, as well as after preincubating the PMN and removal of the drugs. LY333328 is active against the tested enterococci, regardless of their susceptibility to vancomycin, with MICs of 1–2mg/l. It is bacteriostatic against extracellular enterococci at concentrations of 2 μg/ml and above regardless of their resistance to vancomycin. After 4 h incubation at 10 MIC, vancomycin-resistant strains of E. faecium and E. faecalis located intracellularly were reduced by 55% and 90%, respectively. Even after preincubation and removal of the drug, LY333328 had an effect at 10 MIC with a 20–30% reduction in the inoculum. The results suggest that in contrast to vancomycin, LY333328 is active against intracellular vancomycin-resistant enterococci, particularly E. faecalis, even after removal of the extracellular drug. Received: December 15, 1999 · Revision accepted: May 5, 2000     

Molecular epidemiology of Enterococcus sp. isolated in a university hospital in Algeria

Abstract Background: The aim of this study was to describe the epidemiology of enterococci isolated from infections at an Algerian university hospital, and to evaluate the prevalence of vancomycin-resistant enterococci (VRE) and the clonal cluster present in this country. Methods: Patients who presented at Annaba University Hospital with Enterococcus infections were prospectively included over a 1-y period (2010). All Enterococcus sp. isolated were characterized by antibiotic resistance, van and erm genes, repetitive sequence-based polymerase chain reaction (rep-PCR), multi-locus sequence typing (MLST), and virulence genes. Results: A total of 125 Enterococcus isolates recovered from 125 patients (59% female; median age 54 y, range 2-86y) were studied. No differences in epidemiological data were observed between infections by Enterococcus faecalis vs Enterococcus faecium. However a high proportion of E. faecium were resistant to ampicillin (95%). The prevalence of VRE, corresponding to 4 vanC1-Enterococcus gallinarum, was 3.2%. A high level of genomic diversity among strains was noted, with the importance of sequence type (ST) 78 (which belongs to clonal complex (CC) 17) in E. faecium and ST317 and CC2 in E. faecalis. Conclusions: This first study on enterococci isolated in Algeria shows the low prevalence of VRE, but the presence of clonal complexes linked to VRE and vancomycin-sensitive enterococci associated with hospital infections. Moreover the high level of macrolide resistance and/or ampicillin resistance in E. faecium suggests close monitoring of the epidemiology of these strains.     

Increase of the number of vancomycin resistant enterococci (VRE) isolated in Helsinki,Finland

The emergence of hospital acquired infections with bacteria resistant to antimicrobials such as vancomycin resistant enterococci (VRE) has become a worldwide concern. In hospitals in the United States, VRE have spread quickly and currently account for eve     

Distribution of Enterococci in Hong Kong

Objectives: To study the distribution of hospital isolates of enterococci from urines, bile, blood and body fluids and to evaluate different methods for the identification of enterococci.Methods: Enterococci isolated from urine, bile, blood and body fluids collected during 1997 and 1998 were identified by polymerase chain reaction (PCR), API 20 Strep and conventional biochemical tests.Results: A total of 498 non-duplicate enterococci were studied: 398 and 43 isolates from urine and bile, respectively, 49 from blood, two from cerebrospinal fluid and six from body fluids. Both API 20 Strep and PCR gave the same identification results for 240 Enterococcus faecalis isolates, 45 E. faecium isolates and one isolate each of E. gallinarum and E. Casseliflavus. These isolates were re-defined by conventional biochemical tests. PCR could correctly identify 303 (98%) isolates while API 20 Strep could only correctly identify 287 (93%) isolates (99% of E. faecalis and 57–87% of the other Enterococcus sp.). Thus, PCR was used in the identification of the remaining isolates and the identity of isolates other than E. faecalis was subsequently confirmed by biochemical tests.Conclusions: The majority of enterococci isolated wasE. faecalis (81%) while only 15% were E. faecium and 4% the other enterococcal species. PCR could correctly identify E. faecalis while the identity of other enterococcal species had to be confirmed by biochemical tests.