Combined action of sulphamethoxazole and trimethoprim against clinically-isolated sulphonamide-resistant bacteria.
42 strains of gram-negative bacteria, isolated from clinical material, resistant to trimethoprim (TM), sulphamethoxazole (SMZ) or both, have been tested for synergistic sensitivity to TM + SMZ. The combination showed no synergy against strains 'highly resistant' to SMZ (MIC greater than 1 mg/ml). Indifference was invariably observed. However, synergy was seen with strains 'moderately resistant' to SMZ (MIC 100--1,000 microgram/ml). Our results indicate that present techniques for the testing of urinary tract isolates for sensitivity to co-trimoxazole need revision.
D000150:Acinetobacter / Q000187:drug effects; D001419:Bacteria / Q000187:drug effects*; D004338:Drug Combinations; D004352:Drug Resistance, Microbial; D004357:Drug Synergism; D004754:Enterobacter / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects; D007709:Klebsiella / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D013420:Sulfamethoxazole / Q000494:pharmacology*; D014295:Trimethoprim / Q000494:pharmacology*
D004338:Drug Combinations; D014295:Trimethoprim; D013420:Sulfamethoxazole