Epidemiological aspects of healthcase-associated enterococcal infections

Introduction / objectives

Enterococci (E.) have become a significant nosocomial pathogen, and their epidemiology is largely obscured.

Methods

Data were obtained by monitoring of 1946 cases of E. infections in 1983-2010 including 17 outbreaks with 172 patients. Isolates (1728) were tested for susceptibility to ampicillin, gentamycin and vancomycin, 31 epidemic isolates of E.faecium were investigated by MLST (Gdh, PstS, PurK and AtpA loci).

Results

Before 2000 maximal incidence of E. infections in Kemerovo Region hospitals was 0,8/1000 patients and share of E.spp. among all pathogens of HAIs was <2%. During the past decade the incidence of E. infections increased 20-fold and mortality rate increased 5-fold. The E.faecalis/E.faecium ratio was 9:1, but in bacteremia cases E.faecium was predominant. Hospitalized patients had 63% isolation rate of E.faecalis, depending on duration of hospital stay. Primary selection of epidemic E.spp. clones occurred in ICU, further spreading to other units. The E.spp epidemic potential was as high as of S.typhimurium and P.aeruginosa. The level of epidemic hazard was higher for E.faecium compare to E.faecalis. The minimal selection time for epidemic clones of E.spp. was 7 days (maximal circulation-4 months). Specific allelotype of the purK1 gene was related to hospital outbreaks. Infections mainly arised from endogenous sources, mainly after colonization of the gastrointestinal tract by epidemic E.spp. clones, but infection has also spread from patient to patient or by hands of healthcare staff, uniform or indirectly by contaminated surfaces and equipment. About 40% of E.faecalis isolates and 72% of E.faecium isolates were resistant to ampicillin, 79% and 82% - to gentamycin, respectively. The VRE share was 31%. Epidemic clones of E. survived on surfaces in hospital environment for 37 days.

Conclusion

Our findings can be taken into account for prevention of HAIs.

Disclosure of interest

None declared.