Peer-reviewed veterinary case report
Qac genes in dog Staphylococcus pseudintermedius affect chlorhexidine
By Walker, Meagan A et al.·Published in Veterinary surgery : VS·2020·Department of Clinical Studies, Canada·View original on PubMed →
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Original publication title: Presence of Qac genes in clinical isolates of methicillin-resistant and methicillin-susceptible Staphylococcus pseudintermedius and their impact on chlorhexidine digluconate susceptibility.
- Species:
- dog
Plain-English summary
A study found that 74% of dog infections caused by Staphylococcus pseudintermedius, both resistant and susceptible to methicillin, had genes that could make them resistant to certain disinfectants. However, these genes did not significantly affect how well chlorhexidine (a common disinfectant) worked against these bacteria. The only exception was one specific gene (qacG), which was linked to a slightly higher resistance level. Overall, chlorhexidine should still be effective for treating these infections if used properly.
People also search for: dog skin infection treatment · chlorhexidine for dog wounds · Staphylococcus pseudintermedius in dogs
Abstract
OBJECTIVE: To evaluate the presence of quaternary ammonium compound (QAC) (resistance genes, qac A/B, smr, qacG, and qacJ, in clinical isolates of methicillin-susceptible Staphylococcus pseudintermedius (MSSP) and methicillin-resistant S pseudintermedius (MRSP) from dogs and the impact on in vitro chlorhexidine susceptibility. STUDY DESIGN: Experimental in vitro study. SAMPLE POPULATION: Seventy isolates from dogs colonized or infected with MRSP (n = 50) or MSSP (n = 20). METHODS: Agar dilution was used to determine the minimum inhibitory concentration (MIC) of chlorhexidine digluconate. Real-time polymerase chain reaction was used to detect the presence of QAC resistance genes, qacA/B, smr, qacG, and qacJ genes. RESULTS: One or more qac genes were identified in 52 of 70 (74%) isolates. Overall, there was no association between chlorhexidine MIC and the presence of one or more qac genes (P = .85) or the presence of qacA/B (P = .31), smr (P = .72) or qacJ (P = .93) individually. There was an association between qacG and MIC (P = .012), with a median MIC of 1.5 μg/mL for isolates possessing this gene and 1 μg/mL for those not possessing it. CONCLUSION: Quaternary ammonium compound resistance genes were present in MRSP and MSSP isolates. With the exception of qacG, the presence of these genes was not associated with increased MIC. All isolates exhibited MIC 5000 to 80 000 times lower than the concentration recommended for use. CLINICAL SIGNIFICANCE: Despite the presence of QAC genes, chlorhexidine digluconate should be effective against MRSP and MSSP if used correctly.
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Search related cases →Original publication on PubMed: https://pubmed.ncbi.nlm.nih.gov/32196706/