[A study of antichlamydial effect of rokitamycin]

MICs of a new macrolide antibiotic, rokitamycin (RKM), for Chlamydia psittaci and Chlamydia trachomatis were determined. Meanwhile, the organisms were observed under the electron microscope for morphologic changes with the addition of RKM. 1. MICs of RKM for C. psittaci MP and 3 strains of C. psittaci isolated from budgerigars kept by patients ranged from 0.05 to 0.10 microgram/ml, and those for 3 strains of C. trachomatis B, E and L2 ranged from 0.20 to 0.39 microgram/ml. These MICs were higher than MICs of minocycline (MINO), doxycycline and rifampicin, but lower than MICs of erythromycin and midecamycin against these organisms. 2. The addition of MINO or RKM to C. psittaci Izawa and C. trachomatis L2 at concentrations twice as high as MICs resulted in no formation of elementary body or intermediate form inside the inclusion body, and abnormal enlargement of reticulate body containing irregularly distributed cytoplasmic components.