The Prevalence of Virulence Determinants and Antibiotic Resistance Patterns in Methicillin-Resistant in a Nursing Home in Poland.

Nursing homes (NH) contribute to the regional spread of methicillin-resistant (MRSA). Moreover, residents are vulnerable to the colonization and subsequent infection of MRSA etiology. We aimed at investigating the molecular and phenotypic characteristics of 21 MRSA collected from the residents and personnel in an NH (Lublin, Poland) during 2018. All MRSA were screened for 20 genes encoding virulence determinants (-, , , , , , , , , , , , ) and for resistance to 18 antimicrobials. To establish the relatedness and clonal complexes of MRSA in NH we applied multiple-locus variable-number tandem-repeat fingerprinting (MLVF), pulse field gel electrophoresis (PFGE), multilocus sequence typing (MLST) and staphylococcal cassette chromosome (SCC) typing. We identified four sequence types (ST) among two clonal complexes (CC): ST (CC22) known as EMRSA-15 as well as three novel STs-ST6295 (CC8), ST6293 (CC8) and ST6294. All tested MRSA were negative for , , , , and genes. The most prevalent gene encoding toxin was (52.4%; = 11/21), and adhesins were and (100%). Only 9.5% ( = 2/21) of MRSA were classified as multidrug-resistant. The emergence of novel MRSA with a unique virulence and the presence of epidemic clone EMRSA-15 creates challenges for controlling the spread of MRSA in NH.