In vitro Sensitivity of Some Bacteria,their L Forms and Pleuropneumonia-Like Organisms to Antibiotics. ∗ †

Abstract

Summary

The sensitivity of PPLO strains of various origin and of several bacteria and their L forms were examined in the presence of 9 antibiotics. The sensitivity of L forms to the various antibiotics with the exception of penicillin was comparable to that of the parent bacterium. However, the L forms of streptococci and of one Vibrio strain were consistently less sensitive to bacitracin than their bacterial forms.

All PPLO strains, like the L forms, were highly resistant to penicillin. The sensitivities of the parasitic strains to the various antibiotics were uniform; they were markedly resistant to bacitracin and erythromycin, like some bacteria. The 3 saprophytic strains were noticeably less resistant than the parasitic strains to several antibiotics, especially to erythromycin. The sensitivities of all strains of PPLO, of bacteria and of L forms of these bacteria were on the whole comparable.