The first clinical isolates of Enterococcus faecium with the VanA phenotype in a tertiary Greek hospital

E. D. Platsouka*, H. Dimopoulou, V. Miriagou and O. Paniara

Department of Microbiology, Evangelismos Hospital, 45–47 Hipsilantou Street, 10676 Athens, Greece

Sir,

Enterococci are increasingly recognized as important nosocomial pathogens, particularly as aetiological agents of nosocomial bloodstream infections. Vancomycin resistance among enterococci is an emerging nosocomial problem, leaving no therapeutic options in seriously ill patients.1 In Greece, up to now, no significant vancomycin resistance has been reported, except by one study from northern Greece,2 which reported a rate of 7.6%. We report the first nine cases of infections with Enterococcus faecium VanA isolates from February 1999 to March 2000 in our 900-bed tertiary hospital. Four isolates of vancomycin-resistant enterococci (VRE) were from blood, two from peritoneal fluid, two from surgical drainage sites and one from urine. Identification to species level and determination of MICs of several antibiotics were performed using the PASCO ID/MIC system for Gram-positive organisms (Difco Laboratories, Detroit, MI, USA). The MICs of vancomycin and teicoplanin were also determined by Etest. The MICs of vancomycin and teicoplanin were >=256 and 128 mg/L, respectively. The phenotype of all E. faecium isolates was VanA. The results of the susceptibility testing are listed in the TableGo. Molecular strain typing was performed by pulsed-field gel electrophoresis (PFGE) and polymerase chain reaction (PCR) analysis. Genomic DNA of the above nine strains was isolated and cleaved by the restriction endonuclease SmaI. The DNA fragments were detected in 1% pulsed-field certified agarose (Bio-Rad Laboratories, Hercules, CA, USA) with a CHEF-DRIII system (Bio-Rad). The voltage gradient was 6 V/cm. For the first 15 h, the pulse was 1–10 s and for the remaining 8 h it was 10–30 s. PFGE showed similar banding patterns (data not shown), so the VRE isolates were assumed to be related strains. The presence of van genes was detected by PCR, as proposed by Dutka-Malen et al.3 Primers VAN A1 (5'-GCTATTCAGCTGTACTC-3') and VAN A2 (5'-CAGCGGCCATCATACGG-3') were used to amplify a 783 bp fragment of the vanA gene. A 1 kb DNA ladder (Gibco-BRL, Paisley, UK) was used as a size standard. The vanA gene was identified in all tested isolates (data not shown). In the USA, VRE strains reportedly accounted for >25% of all enterococci isolated in intensive care units,4 whilst most European countries have a low incidence of VRE strains.5 In our hospital, we have noticed an increasing proportion of vancomycin-sensitive E. faecium strains during 1992– 96.6 These first cases of E. faecium with the VanA phenotype confirm the emergence of VRE infections in our hospital.


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Table. MICs (mg/L) of 11 antibiotics for nine VRE isolates
 

Notes

J Antimicrob Chemother 2000; 46:1039–1040

* Corresponding author. Tel: +30-1-720-1530; Fax: +30-1-672-7299. Back

References

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3 . Dutka-Malen, S., Evers, S. & Courvalin, P. (1995). Detection of glycopeptide resistance genotypes and identification to the species level of clinically relevant enterococci by PCR. Journal of Clinical Microbiology 33, 24–7.[Abstract]

4 . Murray, B. E. (2000). Vancomycin-resistant enterococcal infections. New England Journal of Medicine 342, 710–21.[Free Full Text]

5 . Schouten, M. A., Voss, A. & Hoogkamp-Korstanje, J. A. (1999). Antimicrobial susceptibility patterns of enterococci causing infections in Europe. Antimicrobial Agents and Chemotherapy 43, 2542–6.[Abstract/Free Full Text]

6 . Routsi, C., Platsouka, E., Paniara, O., Dimitriadou, E., Saroglou, G., Roussos, C. et al. (2000). Enterococcal infections in a Greek intensive care unit: a 5-y study. Scandinavian Journal of Infectious Diseases 32, 275–80.[ISI][Medline]