Corticosteroid treatment and methicillin, quinolone or multidrug resistance in dogs

Antimicrobial resistance is of great concern in human and veterinary medicine. Corticosteroid treatment is often administered together with antibiotics or prior to antibiotic treatment which might influence antibacterial resistance to Staphylococcus pseudintermedius. The objective of this study was to examine whether there is an association between corticosteroid treatment and either methicillin, quinolone or multidrug resistance to Staphylococcus pseudintermedius in dogs presented to the Dermatology Department of the veterinary teaching hospital. Medical records were collected from 138 dogs with pyoderma and otitis externa from which Staphylococcus pseudintermedius was isolated. The bacteria was isolated by bacterial culture and sensitivity tests were performed. Information regarding prior systemic or topical antimicrobial exposure and prior systemic or topical corticosteroid exposure was collected. An association between antibiotic treatment (AB) and multidrug resistance (MDR) was found. There was a significant association between Methicillin-resistant Staphylococcus pseudintermedius (MRSP) and prior antibiotic treatment and similarly between quinolone resistance and prior antibiotic treatment (p<0.05). More MDR cases received antibiotics within one month prior to culture and sensitivity (75.4%) in comparison to all other time frames (p<0.05). An association between intact female dogs and MRSP was found (p<0.01). Of the intact female dogs, 92.3% were MRSP, 76.9% of intact females were MDR (p<0.01). No association was found between prior corticosteroid treatment and MRSP, or quinolone resistance or MDR. An effort was made in order to expose potential confounding variables but none were found. Since a clear association was found between prior antibiotic treatment and resistant S. pseudintermedius, while no association was found between any prior treatment with corticosteroids and MRSP, quinolone resistance or MDR, we concluded that either there is no association between corticosteroids and bacterial resistance, or, at the very least, there is a weaker association than the association between antibiotic treatment and bacterial resistance.