Naslov
Characterization of Extended-spectrum β-lactamases in Enterobacteriaceae Causing Nosocomial Iunfections

Autori
Jajić-Benčić, Ines ; Bedenić, Branka ; Mikoč, Andreja

Izvornik
Journal of Chemotherapy (1120-009X) 21 (2009), 3; 282-289

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
extended-spectrum β-lactamases; ceftazidime; plasmids; SHV-5 β-lactamase

Sažetak
The bacteria producing extended-spectrum β-lactamases (ESBL) have been increasingly reported. Production of extended-spectrum β-lactamases is the major mechanism of resistance to oxymino-cephalosporins and aztreonam in Gram-negative bacteria. The aim of the present study is to characterize ESBLs produced by Enterobacteriaceae, associated with nosocomial infections, collected during 2003-2005 in a University Hospital in Zagreb and to determine the risk factors associated with nosocomial infections caused by ESBL producing Enterobacteriaceae. In total 76 isolates of Enterobacteriaceae were included in the study. Antibiotic susceptibility testing was performed by disk-diffusion and broth microdilution method according to CLSI. ß-lactamases were characterized by PCR and sequencing of blaESBL genes. Plasmids were extracted by alkaline lysis method and digested with Eco RI enzyme. Most of the strains displayed CAZ phenotype which means higher level or resistance to cefazidime compared to cefotaxime and ceftriaxone. Sequencing of blaESBL genes from representative strains revealed SHV-5 β-lactamase in six strains, CTX-M-3 β-lactamase in one E. coli and three K. pneumoniae strain, and CTX-M-15 in one E. coli and three K. pneumoniae strains. According to the plasmid fingerprinting strains were assigned into groups designated from A to F. Spread of SHV-5 producing E. coli strains throughout the hospital units could be due to the selection pressure of cefazidime which is widely prescribed in our hospital and favours survival of the strains possessing mutation at the Ambler position 240 responsible for ceftazidime and aztreonam resistance. Carbapenems are the antibiotics of choice for the treatment of infections caused by our ESBL producing Enterobacteriaceae isolates.

Izvorni jezik
Engleski

Znanstvena područja
Temeljne medicinske znanosti

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