title: Characterization of Klebsiella pneumoniae strains producing extended spectrum beta-lactamases and AMPC type beta-lactamases isolated from hospitalized patients in Kerman, Iran.
abstract: Klebsiella pneumoniae is a major cause of nosocomial infections. Emergence of antibacterial resistance and production of beta-lactamases are responsible for the frequently observed empirical therapy failures. The aim of this study was to determine the presence and the prevalence of extended spectrum beta-lactamases (ESBLs) and AmpC beta-lactamases in clinical isolates of K. pneumoniae in Kerman, Iran. Resistance to different antibiotics was determined using standard disk diffusion method. The beta-lactamases phenotypes were determined by combined disk method. Polymerase chain reaction (PCR) was used to determine blaCTX-M and blaCMY genes in the ESBLs and AmpC positive isolates. Out of the 75 K. pneumoniae isolates, 31 (41.3%) produced ESBLs, 11 (14.6%) produced AmpC beta-lactamases and 1 (1.3%) was resistant to imipenem, probably by the production of a metallo beta lactamase in the phenotypic assay. Simultaneous production of ESBLs and AmpC beta-lactamases as well as the concomitant presence of blaCTX-M and blacMY genes was detected in one isolate. Prevalence of blaCTX-M and blaCMY among isolates were 20% and 2.6%, respectively. Beta-lactam therapy can fail when beta-lactamase-hyper-producing organisms appear in an infection. The occurrence of isolates co-expressing many types of beta-lactamases can cause serious problems, regarding the treatment of infections caused by these pathogens.
authors.affiliation: Department of Microbiology, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Shahla
authors.initials: S
authors.lastname: Mansouri
authors.forename: Davood
authors.initials: D
authors.lastname: Kalantar
authors.forename: Parisa
authors.initials: P
authors.lastname: Asadollahi
authors.forename: Morovat
authors.initials: M
authors.lastname: Taherikalani
authors.forename: Mohammad
authors.initials: M
authors.lastname: Emaneini
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis*; D003428:Cross Infection / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D006801:Humans; D007492:Iran; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D001618:beta-Lactamases / Q000096:biosynthesis*
chemical_list: D001426:Bacterial Proteins; C048795:AmpC beta-lactamases; D001618:beta-Lactamases