CEFUROXIME RESISTANCE IN ESCHERICHIA-COLI - RESISTANCE MECHANISMS ANDPREVALENCE

In order to characterize cefuroxime resistance in Escherichia coli 22 clinical isolates were investigated for susceptibility to different be ta-lactam antibiotics and ciprofloxacin. The production of beta-lactam ases, the pattern of the major outer membrane proteins (OMPs), and the plasmid profiles were determined for these isolates. Ten of the isola tes were resistant to ceftazidime, two to cefotaxime, and none was res istant to imipenem or ciprofloxacin. The dominating resistance mechani sm was hyperproduction of the chromosomally encoded beta-lactamase to some extent accompanied by alterations of the OMP's. Two isolates with low ampicillin MIOs seemed solely to have alteration of the OMPs. Non e of the isolates produced plasmid-mediated extended-spectrum beta-lac tamases. In addition, the prevalence of cefuroxime resistance was inve stigated. The prevalence as attained in 8704 clinical isolates of E. c oli collected from Copenhagen County during a 5-year period (1990-1994 ) was 4.4%, but there was considerable variation among specimens from different sites of the body. Isolates from blood were much less resist ant (2.5%) than isolates from the respiratory tract (9.7%).