[Virulence factors in vancomycin-susceptible and vancomycin-resistant enterococci in the University Hospital Olomouc]

Bacteria of the genus Enterococcus are a normal part of the intestinal microflora but also important nosocomial pathogens. An alarming fact is increasing resistance to antimicrobial agents such as vancomycin (VRE). Enterococci frequently produce numerous virulence factors, e.g. gelatinase, surface protein, adhesins and sex pheromones. Their genes, with respect to vancomycin resistance, are studied.

In 108 isolates obtained from various clinical samples (except for stools) taken from patients in the University Hospital Olomouc and divided into VRE (n = 54) and control, vancomycin-susceptible (n = 54) groups, the prevalence of genes for gelatinase (gelE), surface protein (esp) and sex pheromones (cpd, cob and ccf) was investigated. For genetic detection, real-time PCR was used.

In the control group of vancomycin-susceptible enterococci, only six isolates (11.1 %) showed none of the studied virulence factors. The most prevalent gene was ccf (77.7 %, n = 42), followed by cpd in 66.6 % (36), gelE in 55.5 % (30), esp in 46.3 % (25) and cob in 38.9 % (21). In the VRE group, 17 isolates (31.5%) contained none of the studied genes. More prevalent was esp in 62.9 % (34), substantially less frequent were cpd in 5.6 % (3), cob in 5.6 % (3), ccf in 5.6 % (3) and gelE in 3.7 % (2).

In VRE a smaller occurence, i.e. four out of the five studied virulence factors, were detected. The lower prevalence of genes for virulence factors was probably due to their species representation (substantially higher frequency of Enterococcus faecium in which these genes are mostly much less prevalent).