Colonisation with vancomycin- and linezolid-resistant Enterococcus faecium in a university hospital: molecular epidemiology and risk factor analysis

4th Department of Internal Medicine, Athens University School of Medicine, University General Hospital Attikon, Chaidari, Greece.
International Journal of Antimicrobial Agents (Impact Factor: 4.26). 12/2008; 33(2):137-42. DOI: 10.1016/j.ijantimicag.2008.08.017
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ABSTRACT During a hospital-wide prospective point prevalence survey of faecal carriage and environmental colonisation of vancomycin-resistant enterococci in a tertiary care university hospital in Athens (Greece), five clinical and one environmental isolate from a light switch (all in the haematology ward) were identified as vancomycin- and linezolid-resistant vanA-positive Enterococcus faecium (VLRE). The studied isolates exhibited a linezolid minimum inhibitory concentration of 12microg/mL and carried at least one mutated copy of the 23S rRNA gene, as shown by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis to detect the G2576T mutation. The enterococcal surface protein (esp) gene was detected by PCR in all isolates. Molecular typing with pulsed field gel electrophoresis (PFGE) showed that the environmental and four of the five clinical isolates were genetically related. None of the colonised patients were previously exposed to linezolid, although heavy linezolid use was noted in the institution. A case-control study was performed to assess risk factors for VLRE colonisation. In univariate analysis, immunodeficiency, underlying haematological malignancy, duration of any antimicrobial treatment before VLRE isolation, and hospitalisation in the haematology ward were pointed out as possible risk factors. A multidisciplinary approach including intensified hand hygiene, patient contact isolation, disinfection of the inanimate environment and antibiotic restriction resulted in early containment of the VLRE colonisation outbreak.

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    ABSTRACT: Introduction: Enterococci are opportunistic pathogens which represent one of the leading agents of nosocomial infections, especially urinary tract infections (UTI) in hospitalized patients. The aim of this study was to determine the resistance pattern and the type of resistance genes of vancomycin-resistant Enterococcus from an educational hospital in Iran. Materials and Methods: From February 2012 till February 2013, one hundred and eighty six clinical isolates from different department of educational hospitals were collected and identified as Enterococci and specified by biochemical tests. Identification was confirmed by specific PCR. Antibiotic resistance properties of strains were examined by Kerby-bauer method. PCR was performed for ddlE, ddlF, vanA and vanB genes. Results: One hundred and six (57%) isolates were identified as E. faecalis and 80(43%) of the isolates were identified as E. faecium. 24 isolates had vanA gene and 19 isolates had vanB genes. In E. faecalis isolates, 15 isolates had vanB and 4 isolates had vanA gene. In E. faecium isolates 20 isolates had vanA and 4 isolates had vanB gene. Prevalence of van genes between E. faecalis and E. faecium were significantly different for both vanA and van B (P<0.01, P<0.041, respectively). VRE isolates were sensitive to Linezolid, Nitrofurantoin and Tigecyclin. Discussion: the overall prevalence of VRE was 23.65% that shows an increase in VRE isolation in our region. Also, prevalence of E. faecium dramatically increased from 9% to 43% in the present study. Also increase in Gentamicin resistant isolates was observed, but VRE isolates were sensitive to Linezolid, Tigecyclin and Nitrofurantoin. Stewardships on antibiotic usage in hospitals, especially for antibiotics, which are our last options, can prevent the spread of resistant isolates and loosing all treatment options in the future.
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    ABSTRACT: The aim of this study was to characterize vancomycin-resistant Enterococcus faecium (VREfm) isolates phenotypically and molecularly, and investigate associations between the virulence factors enterococcal surface protein (esp), hyaluronidase (hyl), and collagen adhesin (acm) and colonization/infection. A total of 126 E. faecium [66 VREfm and 60 vancomycin-susceptible (VSEfm)] were collected in West China Hospital. Nine E. faecium isolates (7 VREfm and 2 VSEfm) were selected at random for comparative study in a large region from China. Minimum inhibitory concentrations (MICs) were measured by Etest and agar dilution, vancomycin resistance genes (vanA, vanB, and vanC) and virulence genes (esp, acm, and hyl) were detected by polymerase chain reaction (PCR). Thirty-four VREfm underwent repetitive sequence-based PCR (rep-PCR) and multi-locus sequence typing (MLST). One linezolid-resistant isolate (MIC = 8 μg/ml) was found; none were tigecycline resistant. All 73 VREfm (28 infective strains and 45 intestinal colonizers) had the vanA gene and VanA phenotype. Positivity for esp, hyl, and acm in VREfm was 79.5, 46.6, and 86.3 %, respectively, which was higher than in VSEfm (54.8, 27.4, and 56.5 %, respectively). Among VSEfm, positivity for acm in isolates from pleural or cerebrospinal fluid (84.6 %) was higher than that from blood (32.4 %). There were 11 rep-PCR types (similarity >95 %) and MLST revealed nine sequence types (STs) among the selected isolates. Most VREfm and all VSEfm belonged to clonal complex 17. A new ST was found, with allele sequence (15, 1, 38, 1, 1, 1, 1). In China, most VREfm seem to belong to the classical nosocomial CC17 clone, and many of them have acquired virulence genes, further strengthening a hospital-adapted type.
    European Journal of Clinical Microbiology 01/2014; 33(6). DOI:10.1007/s10096-013-2029-z · 3.02 Impact Factor
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