Related Experiment Videos
Resistance types in Escherichia coli. II. Transfer of ampicillin resistance
Abstract:
The ability to transfer resistance traits was investigated in 49 E. coli strains isolated from clinical specimens. The strains were divided into the three groups according to sensitivity to penicillin derivatives. Group 1 contained 8 ampicillin-carbenicillin sensitive (A-s/Ca-s) strains, group 2 contained 16 ampicillin resistent-carbenicillin sensitive (A-r/Ca-s) strains and group 3 contained 25 ampicillin-carbenicillin resistant strains. In group 3, 17 strains could transfer A-resistance (range of transfer frequency was 10(0.0) to 10(-7.5). The 16 strains in group 2 that did not transfer A-resistance more often than mutants arose from the recipient (10(-8.8). The mutants of the recipient selected on A-plates were A-r/Ca-s/cephalothin-resistant, exactly as the strains in group 2. The A-resistance in group 3 was probably based on plasmids, and that of group 2 was based on mobilizable plasmids and/or chromosomal resistance. The frequencies of transfer of sulphonamide-, tetracycline- and streptomycin resistance of the strains in groups 1 and 2 did transfer, were in the same range as the frequencies of transfer in group 3.
Insights
This study investigated antimicrobial resistance transfer in E. coli clinical isolates. Ampicillin resistance was transferable in some strains, likely via plasmids, while others showed chromosomal resistance.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Antimicrobial resistance (AMR) is a growing global health threat.
- Understanding resistance gene transfer mechanisms is crucial for combating AMR.
- Escherichia coli (E. coli) is a common pathogen where resistance transfer is frequently observed.
Purpose of the Study:
- To investigate the transferability of resistance traits in clinical E. coli isolates.
- To differentiate between plasmid-mediated and other resistance transfer mechanisms.
Main Methods:
- Categorization of 49 E. coli strains based on sensitivity to penicillin derivatives (ampicillin and carbenicillin).
- Assessing the frequency of resistance trait transfer between strains.
- Analyzing resistance profiles of spontaneous mutants.
Main Results:
- Ampicillin resistance was transferable in 17 out of 25 resistant strains (Group 3), with transfer frequencies ranging from 10(0.0) to 10(-7.5).
- Resistance in Group 2 strains (ampicillin-resistant, carbenicillin-sensitive) was less transferable than spontaneous mutants, suggesting mobilizable plasmids or chromosomal resistance.
- Other resistance traits (sulphonamide, tetracycline, streptomycin) showed similar transfer frequencies across sensitive and resistant groups.
Conclusions:
- Ampicillin resistance in E. coli clinical isolates can be mediated by transferable plasmids.
- Mobilizable plasmids and chromosomal mechanisms may also contribute to resistance transfer.
- Further research into resistance transfer dynamics is essential for effective AMR control strategies.