title: A broth-disc technique for the assay of antibiotic synergism.
abstract: A broth-disc technique has been developed to demonstrate the antibiotic synergism of some broad-spectrum penicillins plus an aminoglycoside against Pseudomonas aeruginosa and enterococci. Utilizing the zone sites obtained from Kirby-Bauer susceptibility tests, approximate minimum inhibitory concentrations of each antibiotic upon individual isolates were derived using standard regression curves. One-fourth of each value was calculated and the approximate desired concentration then prepared in Mueller-Hinton broth through use of the labelled antibiotic disc content. Tubes were inoculated with a standardized suspension of organism and incubated at 35 degrees C for 18-24 h. Subsequently, inhibitory end points were recorded. This approach to synergy testing showed good correlation with the standard checkerboard method. The broth-disc synergistic assay is also reproducible, financially feasible, and less time-consuming to execute.
mesh_terms: D000583:Amikacin / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002228:Carbenicillin / Q000494:pharmacology*; D004357:Drug Synergism; D005839:Gentamicins / Q000494:pharmacology*; D007612:Kanamycin / Q000031:analogs & derivatives*; D008826:Microbial Sensitivity Tests / Q000379:methods*; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D013291:Streptococcus / Q000187:drug effects; D014031:Tobramycin / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D005839:Gentamicins; D007612:Kanamycin; D000583:Amikacin; D002228:Carbenicillin; D014031:Tobramycin