Temperature effects on minimum inhibitory and bactericidal concentrations of cell wall antibiotics in Streptococcus faecalis.

The minimal inhibitory and bactericidal concentrations were determined at 30 and 37 degrees C for several antibiotics affecting cell wall biosynthesis. The test organism, Streptococcus faecalis ATCC 9790, possesses a single autolytic enzyme and does not produce penicillinase. Penicillin, methicillin, and, possibly, bacitracin appeared more effective at 37 than at 30 degrees C. Vancomycin, ristocetin, and phosphonomycin appeared equally effective at both temperatures, and cycloserine appeared consistently more active at 30 than at 37 degrees C.