title: Diminished effect of gentamicin under anaerobic or hypercapnic conditions.
abstract: The in-vitro activity of gentamicin, judged by M.I.C. determinations, was much reduced when a normal aerobic atmosphere was replaced either by air +4% CO2 or by anaerobic conditions. The phenomenon was greatest for Staphylococcus aureus, where a decrease in activity of up to 20-fold was found. For Escherichia coli, Klebsiella aerogenes, Enterobacter spp., and Proteus spp. the factor of decrease was between 15-fold and 2-5-fold. Changes in medium pH, as a result of bacterial growth, can explain these findings for some, but not all, the species tested.
mesh_terms: D000693:Anaerobiosis; D001419:Bacteria / Q000187:drug effects*; D002245:Carbon Dioxide / Q000494:pharmacology*; D003470:Culture Media; D046508:Culture Techniques; D004755:Enterobacteriaceae / Q000187:drug effects / Q000254:growth & development; D005839:Gentamicins / Q000494:pharmacology*; D006859:Hydrogen; D006863:Hydrogen-Ion Concentration; D008826:Microbial Sensitivity Tests; D013210:Staphylococcus / Q000187:drug effects / Q000254:growth & development
chemical_list: D003470:Culture Media; D005839:Gentamicins; D002245:Carbon Dioxide; D006859:Hydrogen