The antimicrobial susceptibility of Escherichia coli isolated in eastern area of Romania. A surveillance study

To evaluate the resistance trends for Escherichia coli isolates during 1993-1999 period in Eastern Romania to: ampicillin (A), ampicillin-sulbactam (A/S), ceftazidime (CAZ), cefotaxime (CTA), ceftriaxone (CRO), aztreonam (AZT), ofloxacin (OF), ciprofloxacin (CIP), tetracycline (T) and chloramphenicol (C). We tested 2012 clinical isolates obtained from faeces and urine. MICs were determined by a dilution method in Mueller-Hinton agar (NCCLS guidelines). Resistance rates were analyzed using the NCCLS breakpoints for the fully susceptible category (moderately susceptible strains were classified as resistant). No significant differences were observed in susceptibility of E. coli to ampicillin and ampicillin/sulbactam in the last years. The high percentage of resistant isolates was observed in 1995 for ampicillin (89.7%). Higher incidences of resistance were detected for A, A/S, T; the addition of sulbactam restored A susceptibility only for a small percent. CAZ, CTA, CRO, AZT, OF and CIP resistance among E. coli isolates was progressively increased in the last period.