Distribution of disinfectant resistance genes qacA/B in clinical isolates of meticillin-resistant and -susceptible Staphylococcus aureus in one Belgrade hospital.

摘要

Many cationic antisceptic agents are used in the prevention of nosocomial infections caused by meticillin-resistant Staphylococcus aureus (MRSA). However, overuse of antiseptic agents has led to the emergence of MRSA with decreased antiseptic susceptibility, and these strains have been isolated from clinical samples and settings. At least 12 antiseptic resistance genes (qacA to qacJ, smr and norA) have been identified in Staphylococcus spp., of which four {qacA, qacB, smr and norA) are found mainly in clinical isolates of S. aureus The qacA gene confers resistance to organic cations, including monovalent cations (ethidium, benzalkonium, cetrimide) and divalent cations (chlorhexidine, pentamidine). It is located on chromosomes and on plasmids, including the pSK1 family of plas-mids. The qacB gene confers resistance to monovalent organic cations and at low levels to some divalent compounds. It is located on several plasmids such as beta-lactamase and heavy metal resistance plasmids (pSK23). qacA and qacB are considered to be virtually indistinguishable apart from seven or nine bases, so it is difficult to distinguish qacA and qacB by simple polymerase chain reaction (PCR).