[Possible synergic action of some drug combinations against Mycoplasma gallisepticum]

Yamamoto and Adler's method (1956), making use of the modified medium of Edward, was employed to determine the minimal concentrations of gentamicin (GMC), erytrhomycin (ERM), oleandomycin (OMC) spectinomycin (SPM), tetracycline (TC), tylosin (TLS), and chloramphenicol (CA), all of them showing bactericidal effects on Mycoplasma gallisepticum-S6, applied alone or in combination. In vitro studies showed that relatively most effective were TLS, GMC, and SPM, when used alone. Combining the antibiotics by two in the most cases led to a pronounced synergic effect. Comparatively most effective were the combinations of TLS+ERM; TLS+TC; CA+TC; CA+OMC; TLS+CA; TLS+OMC; SPM+TC; and SPM+CA. Lowest absolute concentrations of the individual components showed the combinations of TLS+GMC; TLS+TC; TLS+ERM; TLS+CA; TLS+SPM; TLS+OMC; SPM+TC; and SPM+CA.