POPULATION ANALYSIS OF SENSITIVITY TO AMPICILLIN AND CARBENICILLIN IN ESCHERICIA COLI AND ENTEROBACTER CLOACAE

Autor: Per Søgaard
Rok vydání: 2009
Předmět:
Zdroj: Acta Pathologica Microbiologica Scandinavica Series B: Microbiology. :235-241
ISSN: 0108-0180
DOI: 10.1111/j.1699-0463.1982.tb00111.x
Popis: 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. 10-6.8.
Databáze: OpenAIRE