Acta Microbiologica 22. (1975)
2. szám - Gadó, I.–Dumbovich, I.: Effect of Some Aminoglycosides Upon a Drug Dependent Escherichia coli Strain
Acta microbiol. Acad. Sei. hung. 22, 95 — 104, 1975 EFFECT OF SOME AMINOGLYCOSIDES UPON A DRUG DEPENDENT ESCHERICHIA COLI STRAIN I. Gadó and I. Dumbovich Section of Microbiology, Research Institute for Pharmaceutical Chemistry, Budapest (Received February 26, 1974) Summary. Escherichia coli Sd-4-73 drug dependent strain was sensitive to kanamycin, gentamicin and neomycin in the absence of drugs stimulating cell multiplication. This sensitivity was not considerably influenced by streptomycin, while paromomycin afforded protection against both bacteriostatic and bactericidal effects. The paromomycin concentration optimum for protection was different from its concentration optimum for multiplication. In an earlier paper [1] evidence has been presented that streptomycin (Sm) dependent Escherichia coli strain grew on short-chained alcohols in the absence of Sm. On the basis of this finding, Gorini et al. [2] discovered a phenomenon which they termed “phenotypic masking”, and also the existence of drugn strains, whose drug requirement can be satisfied with Sm, paromomycin (Pm) or alcohols. These authors studied the colony forming of the drugD strain on agar plates containing kanamycin A (Km) (Table I). Later a partial inhibition was described in the case of a Pm-fKin combination, which was explained by a competition of Pm and Km [3, 4]. In the case of drug0 strain, the bactericidal effect of Km could only be observed when the inoculum had grown on Sm-containing medium, and this bactericidal effect was weaker than the one observed with E. coli В strain [3]. From these results Table I Growth of drugD E. coli mutant on Km containing solid media* Drug in medium Drug in inoculum Nil Km Pm + Km Sm + Km EtOH + Km EtOH— — + — — Sm± — — — — Pm± — + — + * After Goiîini et al. [2]. Acta Microbiologica Academiae Scientiarum Hungaricae 22,1975