Antibiotic susceptibility patterns among respiratory isolates of Gram-negative bacilli in a Turkish university hospital

Abstract

Background: Gram-negative bacteria cause most nosocomial respiratory infections. At the University of Cumhuriyet, we examined 328 respiratory isolates of Enterobacteriaceae and Acinetobacter baumanii organisms in Sivas, Turkey over 3 years. We used disk diffusion or standardized microdilution to test the isolates against 18 antibiotics. Results: We cultured organisms from sputum ( 54%), tracheal aspirate ( 25%), and bronchial lavage fluid ( 21%). The most common organisms were Klebsiella spp ( 35%), A. baumanii ( 27%), and Escherichia coli ( 15%). Imipenem was the most active agent, inhibiting 90% of Enterobacteriaceae and A. baumanii organisms. We considered approximately 12% of Klebsiella pneumoniae and 21% of E. coli isolates to be possible producers of extended-spectrum beta-lactamase. K. pneumoniae isolates of the extended-spectrum beta-lactamase phenotype were more resistant to imipenem, ciprofloxacin, and tetracycline in our study than they are in other regions of the world. Conclusions: Our results suggest that imipenem resistance in our region is growing.