Susceptibility of a trachoma agent grown in FL cell cultures to antibiotics and a sulfa drug.

Abstract

FL cell cultures infected with the T'ang strain (TE55) of trachoma have been used to evaluate the effect of a number of antibiotics and a sulfa drug. Complete inhibition was observed by doses of 0.1 μg/ml of tetra- and oxytetracycline. Chloramphenicol, erythromycin and chlortetracycline were effective in 10–100 times higher doses. Penicillin prevented the appearance of infective particles in doses of 0.1 unit/ml. Lower doses of the antibiotics showed a partial inhibiting effect. Both penicillin and tetracycline also inhibited the agent when added in the later stages of its developmental cycle. The sulfa drug sulfanilamido-3phenyl-2pyrazole prevented the appearance of infective particles in doses of 100 μg/ml. Its inhibitory effect was limited to the early developmental stages of the agent, and could be reversed by PABA, folinic and folic acid. Aminopterin, like the sulfa drug, inhibited the agent at an early stage of development. No inhibition was observed when large doses of streptomycin, bacitracin and neomycin were employed.