IN VITRO SENSITIVITY OF MYCOPLASMAS ISOLATED FROM VARIOUS ANIMALS AND SEWAGE TO ANTIBIOTICS AND NITROFURANS

Abstract

A total of 15 strains of Mycoplasma were examined for in vitro sensitivity to 22 commonly used antibiotics and 9 nitrofurans. They were strains of Mycoplasma mycoides var. mycoides, M. mycoides var. capriy, M. hyorhinis, M. suipneumoniae (hyopneumoniae), M. granularum, M. cams, M. pulmonis, M. arthritidis, M. neurolyticum, M. gallisepticum, and M. laidlawii, all of which were isolated from various animals, except for one strain of M. laidlawii which was isolated from sewage. The sensitivity was determined by observing inhibition of growth in the agar and broth dilution systems. Amongall the mycoplasmasexamined, there were no markeddifferences in susceptibility to these drugs, with the exception of erythromycin and oleandomycin. Antitumor antibiotics, i. e., actinomycin D and mitomycin C, were the most active of all the agents. Tylosin, bottromycin, spiramycin and tetracycline followed them in activity. Kasugamycin, polymyxin B and colistin were noninhibitory. M. suipneumoniaea, which is known as the etiological agent of swine enzootic pneumonia (SEP), and other species of respiratory mycoplasmas of swine were compared with regard to minimuminhibitory concentrations (MIC) upon these drugs. The sensitivity of M. suipneumoniae to the drugs used was similar to that of other mycoplasma.Amongthe new nitrofurans tested, drugs with high activity against the mycoplasma were discovered.