title: The in vitro resistance of canine staphylococci to trimethoprim and sulphamethoxazole alone and in combination.
abstract: The in vitro resistance of 40 strains of Staphylococcus aureus isolated from dogs to trimethoprim, sulphamethoxazole and co-trimoxazole (SXT) was assessed using the disc diffusion technique on Diagnostic Sensitivity Test Agar (DSTA), DSTA with 5% lysed horse blood (DSTA + B), IsoSensitest Agar (ISTA) and Wellcotest Sensitivity Test Agar (WSTA). When sensitivity was based on a zone width of greater than or equal to 4 mm all 40 strains were sensitive to SXT on DSTA + B and ISTA, 39 were sensitive on WSTA while only 31 (77.5%) were sensitive on DSTA. A comparison of the results obtained for each strain for trimethoprim and sulphamethoxazole with those obtained with the Oxford strain of S. aureus and using a scheme for interpretation recommended by Garrod & O'Grady (1971) indicated that the proportion of strains classed as sensitive for therapeutic purposes was 5%, 55%, 47.5% and 15% respectively on DSTA, DSTA + B, ISTA and WSTA.
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000382:microbiology*; D004285:Dogs; D004338:Drug Combinations / Q000494:pharmacology; D004352:Drug Resistance, Microbial; D008826:Microbial Sensitivity Tests; D013203:Staphylococcal Infections / Q000382:microbiology / Q000662:veterinary; D013210:Staphylococcus / Q000187:drug effects*; D013420:Sulfamethoxazole / Q000494:pharmacology*; D014295:Trimethoprim / Q000494:pharmacology*; D015662:Trimethoprim, Sulfamethoxazole Drug Combination
chemical_list: D004338:Drug Combinations; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D014295:Trimethoprim; D013420:Sulfamethoxazole