Abstract
Cefotaxime (CTX) disks and ampicillin (ABPC) disks exhibited synergism against 24 strains of Streptococcus D group isolated from various sources in our hospital.
We were interested in these synergism effec ts and compared them with the combination index.
Twenty-two out of the 24 strains examined exhibited synergism, and were identified as Streptococcus faecalis by the API strep system.
We divided th em into 4 groups (combination index: 19, 15, 11, 9) according to the degree of synergism. Another 2 strains showed additive effects (combination index: 1), and were identified as Streptococcus faecium.
Among these 24 strains,β-lactamases were produced by only 1. There was no direct connection between β-lactamase production and synergism. The mechanism of synergism between CTX and ABPC has not yet been studied.
