Multidrug resistance to antiseptics and disinfectants in coagulase-negative staphylococci

Abstract

Summary. The occurrence of resistance to antiseptics and disinfectants in clinical isolates of coagulase-negative staphylococci (CNS) was examined. Of 164 clinical strains of CNS isolated in the early 1980s, 65 were resistant to cationic antimicrobial compounds such as cetyltrimethylammonium bromide. Further characterisation of 40 resistant isolates by DNA-DNA hybridisation analysis and phenotypic resistance studies revealed that this resistance was mediated by the multidrug export genes qacA and qacC, characterised previously in Staphylococcus aureus. Of the resistant CNS isolates, 50 YO contained only qacA, 10% contained only qacC, and the remaining 40% contained both qacA and qacC. Both qacA and qacC genes resided on plasmids in all cases, with qacA located on plasmids of > 10 kb, whereas qacC was located primarily on plasmids of 2-3 kb. Representative qacA and qacC plasmids were characterised by restriction endonuclease mapping, and were found to be similar in some cases, but different in others, to those plasmids on which these genes are found in S. aureus.

Disinfectant and antibiotic activities: a comparative analysis in Brazilian hospital bacterial isolates

“…An existing cross-resistance between QACs and aminoglycosides, codified by plasmids, has been reported in MRSA strains, leading to the suggestion that the extensive use of cationic agents in the hospital environment can be a factor responsible for the emergence of resistant strains to antibiotic agents (6,25). Recently, resistance to cationic agents and to antibiotics mediated by the same plasmids has been also observed in coagulase-negative staphylococci (CoNS), microorganisms associated with infections in implanted foreign bodies (12). Tennent and coleagues (24) suggested that staphylococci evade destruction because the protein specified by the qacA determinant, located in a plasmid locus, is a cytoplasmic membrane-associated protein involved in an efflux system that actively reduces intracellular accumulation of the QAC.…”

High Rate of qacA - and qacB -Positive Methicillin-Resistant Staphylococcus aureus Isolates from Chlorhexidine-Impregnated Catheter-Related Bloodstream Infections

“…The Qac multipledrug-resistant pumps QacA, QacB, and QacC have been shown to confer resistance to various antimicrobial organic cations. The QacA pump is responsible for high-level resistance to both biguanidines (e.g., chlorhexidine) and diamidine (e.g., pentamidine) (13), and the QacC (Smr) pump is responsible for quaternary ammonium resistance (7). The difference between QacB and QacA is a single amino acid substitution at position 323, leading to a lower resistance level of biguanidines and diamidine in QacB (13).…”

Enterotoxin production by coagulase-negative staphylococci in restaurant workers from Kuwait City may be a potential cause of food poisoning

“…However, detection of resistance to propamidine isethionate in 11.2% of the isolates was significant. Propamidine isethionate and quaternary ammonium compounds are components of household disinfectants and antiseptics [36,371, and resistance to propamidine isethionate is usually linked to resistance to quaternary ammonium compounds [36,37]. Therefore their resistance may diminish the usefulness of antiseptics containing them as hand-washing agents for removing enterotoxigenic staphylococci from the hands and preventing their cross-contamination.…”