Background: In the Małopolska province, the first case of vancomycin resistant enterococci (VRE) occurrence was an outbreak in 2001 caused by strains of the genus E. faecium carrying the vanA operon.
Objectives: The aim of this study is to determine the antimicrobial resistance and the occurrence of virulence determinants among Enterococcus spp. in patients hospitalized in the Małopolska region in 2015.
Material and methods: Antimicrobial susceptibility was determined by disc diffusion and the E test. The presence of aminoglycoside and glycopeptide resistance genes and virulence genes (asa1, gelE, cylA, esp, hyl) was investigated using multiplex polymerase chain reaction (PCR). Also, the presence of IS16 was investigated. The activity of gelatinase, cytolysin (hemolysin), and DNase was tested.
Results: All E. faecalis were susceptible to ampicillin, vancomycin, teicoplanin, linezolid and tigecycline. All E. faecium strains were susceptible to quinupristin-dalfopristin. Resistance to ampicillin and vancomycin was detected among all E. faecium isolates from hospitals C and D. 87.32% of E. faecium presented high-level aminoglycoside-resistant (HLAR) phenotype, including 78.33% of strains from hospital C and 100% from hospital D. In hospital C (98.3%) and D (96%), resistance to ciprofloxacin, levofloxacin and norfloxacin was observed. Gene esp was detected in all E. faecium isolates and the majority of E. faecium isolates carried hyl (97%). In E. faecalis, different combinations of virulence genes were detected. All analyzed E. faecium strains showed the presence of IS16 insertion element.
Conclusions: E. faecalis isolates were more susceptible to antimicrobials than E. faecium, which were largely multidrug-resistant. E. faecalis strains have diverse virulence factors. E. faecium showed a high percentage of hyl and esp genes and the presence of IS16.
Keywords: Enterococcus; antimicrobial susceptibility; healthcare-associated infections; vancomycin resistant enterococci (VRE); virulence factors.