Transfer of antibiotic resistance and production of extended-spectrum β-lactamase (ESBL) in nosocomial Klebsiella pneumoniae strains from two hospitals in Czech Republic

Summary Six Klebsiella pneumoniae strains were collected from two hospitals in Ostrava, Czech republic. Four strains (Nos. 209, 217, 218, 222) were isolated from sputa of critically ill patients from Municipal Hospital Vitkovice — Ostrava. They were resistant to cephalothin, cefotaxime, and ceftazidime (MIC > 100 mg × 1 -1 ). Strain No. 218 was intermediately resistant also to ofloxacin and aztreonam (MIC = 12.5 mg × 1 -1 ), strain No. 222 wa resistant to aztreonam (MIC = 50 mg × 1 -1 ). Determinants of resistance to cephalothin, cefotaxime, aztreonam and ceftazidime were transferred to re strains of P. mirabilis P-38 rif + and E. coli K-12 No. 3110 rif + by all four strains. Synergy between clavulanate-cefotaxime, clavulanate-ceftazidime and clavulanate-aztreonam indicated production of ESBLs by these strains. Two strains, No. 214 and 224, from patients of the ICU in the University Hospital were resistant to cephalothin, cefotaxime and ceftazidime (MIC > 100 × 1 -1 ). Strain No. 214 was intermediately resistant to aztreonam and ofloxacin (MIC = 12,5 mg × 1 -1 ) and strain No. 224 was highly resis aztreonam (MIC = 50 mg × 1 -1 ). Synergy between clavulanate and cefotaxime as well as between clavulanate and aztreonam, but not between clavulanate ceftazidime corresponds with non-transferable ceftazidime resistance in strains No. 214 and 224 and indicates different types of ESBL in strains from each of two hospitals.