BETA-LACTAM RESISTANCE IN AEROBIC FECAL FLORA FROM GENERAL-PRACTICE PATIENTS IN THE UK

One hundred faecal specimens submitted to a diagnostic laboratory in E dinburgh and found to be negative for gastrointestinal pathogens were examined for the presence of antibiotic-resistant bacteria. The result s were compared with findings in the healthy population in the same ar ea. The highest incidence of resistance was observed to cefuroxime (65 %) and ampicillin (60 %). Of the ampicillin-resistant isolates, 62 % could transfer their resistance determinants to a standard Escherichia coli host strain. In 100 % of these transconjugants ampicillin resist ance was shown to result from the presence of the TEM-1 beta-lactamase which was identified in a heterogeneity of plasmid profiles. These pl asmids commonly mediated resistance to streptomycin and tetracycline i n addition to ampicillin.