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POPULATION ANALYSIS OF SENSITIVITY TO AMPICILLIN AND CARBENICILLIN IN ESCHERICIA COLI AND ENTEROBACTER CLOACAE
Author(s) -
SØGAARD PER
Publication year - 1982
Publication title -
acta pathologica microbiologica scandinavica series b: microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.909
H-Index - 88
eISSN - 1600-0463
pISSN - 0108-0180
DOI - 10.1111/j.1699-0463.1982.tb00111.x
Subject(s) - enterobacter cloacae , carbenicillin , escherichia coli , ampicillin , microbiology and biotechnology , mutant , population , enterobacter , chemistry , enterobacteriaceae , biology , antibiotics , biochemistry , gene , medicine , environmental health
Population analysis of sensitivity to ampicillin (A) and carbenicillin (Ca) was carried out with four strains of E. coli and five strains of Enterobacter cloacae. The two A‐sensitive/Ca‐sensitive (A‐s/Ca‐s) E. coli strains were homogeneous as regards A‐sensitivity. From the A‐resistant/Ca‐s (A‐r/Ca‐s) E. coli strains, it was possible to select A‐r/Ca‐r mutants. Mutation frequency approx. 10 ‐7.5 . When the inoculum of A‐s/Ca‐s E. coli was raised, it was possible to select A‐r/Ca‐s/cephalothin‐r variants with a frequency of approx. 10‐ 9.7 . In this laboratory 5% (10 ‐1.3 ) of the received E. coli strains are A‐r/Ca‐s. These strains might consequently be mutants of the usual A‐s/Ca‐s E. coli , selected in an ampicillin environment. The two A‐s/Ca‐s E. cloacae strains developed mutants highly resistant to A, thereby differing from the A‐s/Ca‐s E. coli strains. The mutation frequency was approx. 10 ‐7.2 . Likewise it was possible to select A‐r/Ca‐r E. cloacae strains from the usual A‐r/Ca‐s ones. Mutation rate approx.