CEFUROXIME RESISTANCE IN KLEBSIELLA-PNEUMONIAE - SUSCEPTIBILITY TO CEFOTAXIME AND CEFTAZIDIME DESPITE PRODUCTION OF ESBLS

The production of beta-lactamases, the outer membrane protein (OMP) pa tterns, some clinical impacts and the prevalence of resistance among c efuroxime-resistant Danish clinical isolates of Klebsiella pneumoniae were investigated. Fifteen resistant and five susceptible strains were collected from 14 patients during 1991-1994. Isolates from five patie nts produced extended-spectrum beta-lactamases (ESBLs). Cefuroxime res istance was accompanied by a IO-fold elevation of ciprofloxacin minima l inhibitory concentration (MIG), and for some isolates by an alterati on of the OMP pattern. The relationship between alterations of the OMP patterns and cross-resistance to ciprofloxacin and the other antibiot ics tested was not universal. Ten of the cefuroxime-resistant strains had elevated MICs of cefotaxime or ceftazidime, but the MICs were stil l below the breakpoint for susceptibility. The MICs of imipenem were n ot affected, Nosocomial infection or long-term colonization with resis tant strains may be of importance since five patients were not treated with cefuroxime prior to isolation of the resistant strain, and all p atients had either serious diseases or stayed at the hospital for a lo ng period of time. The prevalence of cefuroxime and ciprofloxacin resi stance among clinical isolates from Copenhagen county during 1990-1995 was 8.3% and 7.5%, respectively, but higher for urinary tract specime ns. A greater consumption of cefuroxime as compared to cefotaxime and ceftazidime in this study, as seen generally in Denmark, indicated tha t ESBLs produced by the investigated strains of K. pneumoniae may be s elected with cefuroxime.