Characterization of Staphylococcal Cassette Chromosome mec (SCCmec) in Methicillin-Resistant Staphylococcus epidermidis Strains Isolated from Biomaterial-Associated Infections and their Antibiotic Resistance Patterns

This work aims to provide an insight into staphylococcal cassette chromosome mec elements and antibiotic resistance in clinical isolates of Staphylococcus epidermidis. The dominating type was SCCmec – IV. Fifteen isolates were assigned to SCCmec type III, two isolates to SCCmec type II. Most isolates were resistant to at least three of the non-β-lactam antibiotics tested. None of the strains exhibited resistance to new generation antibiotics, such as daptomycin and linezolid. Also, none of these strains showed resistance to tigecycline and only four strains were resistant to rifampin i.e. antibiotics which are very efficient in treating biofilm-associated infections

Characterization of SCCmec types, antibiotic resistance, and toxin gene profiles of Staphylococcus aureus strains

Methicillin-resistant Staphylococcus aureus (MRSA) causes serious nosocomial and community acquired infections. Resistance to methicillin is mediated by the mecA gene, which is inserted in a mobile genetic element called staphylococcal cassette chromosome mec (SCCmec). We determined the SCCmec types, the occurrence of genes encoding toxic shock syndrome toxin (tst), exfoliative toxin (eta, etb), Panton-Valentine leukocidin (pvl) as well as antibiotic susceptibility of these isolates. Among 65 hospital-acquired methicillin-resistant S. aureus (HA-MRSA) strains, SCCmec types II, III and IV were identified. Type III SCCmec was the most prevalent (62%), followed by mec types II (24%) and IV (14%). Four community acquired methicillin-resistant S. aureus (CA-MRSA) strains carried SCCmec type IV and were pvl-positive. The most prevalent gene among HA-MRSA was pvl. The toxic shock syndrome toxin and exfoliative toxin genes were found only in hospital-acquired methicillin-resistant S. aureus. The results of this study demonstrate that the SCCmec type III is predominant among strains recovered from hospitalized patients with infections and that these strains were resistant to many antibiotics used in the treatment of staphylococcal infections