Description:
<jats:title>ABSTRACT</jats:title>
<jats:p>
The present investigation was undertaken to assess the proportion of methicillin-resistant
<jats:italic>Staphylococcus aureus</jats:italic>
(MRSA) strains among hospital-acquired isolates and to determine the clones of MRSA currently circulating in Poland by using a number of molecular techniques. Between January and May 2005, methicillin resistance was investigated among a total of 915
<jats:italic>S. aureus</jats:italic>
isolates collected from 39 hospitals. A total of 208 (22.7%) isolates were positive for the
<jats:italic>mecA</jats:italic>
gene by PCR. The molecular characterization of MRSA isolates was carried out by the multiple-locus variable-number tandem repeat fingerprinting, pulsed-field gel electrophoresis, multilocus sequence typing, and staphylococcal chromosomal cassette
<jats:italic>mec</jats:italic>
(SCC
<jats:italic>mec</jats:italic>
) typing methods. The Hungarian (PFGE B; ST239, SCC
<jats:italic>mec</jats:italic>
type III [ST239-III]), Iberian (ST247-I), and Berlin (ST45-IV) clones were predominant, representing approximately 52.9, 11.5, and 10.0% of the MRSA isolates, respectively. A decline in the proportion of earlier MRSA clones, such as ST5-IV (a Pediatric clone), ST80-IV) (a Mediterranean clone), ST239-III (a Polish and Brazilian clone), and ST30-IV (a southwest Pacific clone) was observed. Additionally, the emergence of an MRSA clone with SCC
<jats:italic>mec</jats:italic>
type V, possibly representing a community-acquired strain, was observed in two hospitals during this study.
</jats:p>