| Summary: | Methicillin-resistant (MR) <i>Staphylococcus aureus</i> (SA) and others, except for <i>Staphylococcus aureus</i> (SOSA), are common in healthcare-associated infections. SOSA encompass largely coagulase-negative staphylococci, including coagulase-positive staphylococcal species. Biofilm <i>formation</i> is encoded by the <i>icaADBC</i> operon and is involved in virulence. <i>mecA</i> encodes an additional penicillin-binding protein (PBP), PBP2a, that avoids the arrival of β-lactams at the target, found in the staphylococcal cassette chromosome <i>mec</i> (SCC<i>mec</i>). This work aims to detect <i>mecA</i>, the <i>bap</i> gene, the <i>icaADBC</i> operon, and types of SCC<i>mec</i> associated to biofilm in MRSA and SOSA strains. A total of 46% (37/80) of the strains were <i>S. aureus</i>, 44% (35/80) <i>S. epidermidis</i>, 5% (4/80) <i>S. haemolyticus</i>, 2.5% (2/80) <i>S. hominis</i>, 1.25% (1/80) <i>S. intermedius</i>, and 1.25% (1/80) <i>S. saprophyticus</i>. A total of 85% were MR, of which 95.5% showed <i>mecA</i> and 86.7% β-lactamase producers; thus, <i>Staphylococcus</i> may have more than one resistance mechanism. Healthcare-associated infection strains codified type I-III genes of SCC<i>mec</i>; types IV and V were associated to community-acquired strains (CA). Type II prevailed in MRSA <i>mecA</i> strains and type II and III in MRSOSA (methicillin-resistant staphylococci other than <i>Staphylococcus aureus</i>). The operon <i>icaADBC</i> was found in 24% of SA and 14% of SOSA; probably the arrangement of the operon, fork formation, and mutations influenced the variation. Methicillin resistance was mainly mediated by the <i>mecA</i> gene; however, there may be other mechanisms that also participate, since biofilm production is related to genes of the <i>icaADBC</i> operon and methicillin resistance was not associated with biofilm production. Therefore, it is necessary to strengthen surveillance to prevent the spread of these outbreaks both in the nosocomial environment and in the community.
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