beta-Lactum resistance in aerobic commensal faecal flora.
Faecal specimens from 100 healthy volunteers living in Edinburgh were examined for the presence of antibiotic-resistant bacteria. A high incidence of ampicillin resistance was found as 42% of specimens containing normally sensitive bacteria were resistant to the drug; however, only 12% of the specimens contained trimethoprim-resistant bacteria. There was no detectable resistance to the third-generation cephalosporin, ceftazidime or the 4-quinolone, ciprofloxacin. Identification of the beta-lactamases produced by the ampicillin-resistant isolates demonstrated that the TEM-1 beta-lactamase predominated particularly in E. coli where it was identified in 86% of isolates. Thirty-three percent of the ampicillin-resistant isolates were able to transfer their resistance to E. coli K12 strain J62-2 and analysis of these transconjugants by iso-electric focusing revealed that the TEM-1 beta-lactamase was present in 100% of the transconjugants. Restriction endonuclease fingerprinting of the TEM-1 containing plasmids suggested the presence of an epidemic plasmid in the community.
Shanahan
P M
PM
Department of Medical Microbiology, The Medical School, University of Edinburgh, Edinburgh, UK.
Thomson
C J
CJ
Amyes
S G
SG