High biofilm production by invasive multiresistant staphylococci.

Biofilm-forming staphylococci are known for being opportunistic and invasive pathogens that cause severe disease, mostly catheter-related infections. Early detection and pathogenic strains carrying highly transferable resistance cassettes epidemiology are essential for infection spread control. Hence, this study was designed to evaluate staphylococci biofilm formation and SCCmec typing. Biofilm production and SCCmec typing were evaluated using a semi-quantitative method based on microtiter plates and a multiplex PCR for types, I-V, respectively. Blood cultures and peripheral intravenous device (IVD) staphylococci were consecutively enrolled and allocated into two different groups (invasive and colonizing) based on clinical and microbiological criteria. Seventy-four invasive and 30 colonizing isolates from distinct patients were studied. Vancomycin was the most administrated antimicrobial agent among these patient's treatments. Biofilm formation was observed in 89% of invasive and 64% of colonizing isolates (p < 0.05). There was significant difference regarding SCCmec typing between colonizing and invasive isolates when harboring SCCmec types IV or V (p < 0.05), but no correlation between biofilm intensity and SCCmec types was verified. The SCCmec elements spread are still ongoing and for that reason, antimicrobial resistance evolution in invasive and colonizing biofilm-forming staphylococci is highly relevant.