In vitro activity of a group of broad-spectrum cephalosporins and other beta-lactam antibiotics against Chlamydia trachomatis.

The activities of seven broad spectrum cephalosporins, four other beta-lactam antibiotics, and one monobactam against Chlamydia trachomatis were measured in a cell culture system. The minimal inhibitory concentration of four of the seven cephalosporins was greater than or equal to 128 micrograms/ml; those of the other three were from 16 to 32 micrograms/ml. Of the other agents, only mecillinam had activity against C. trachomatis comparable to that reported for ampicillin (minimal inhibitory concentration, less than or equal to 0.5 micrograms/ml).