Detection and characterization of DHA-1 beta-lactamase in Klebsiella spp. causing urinary tract infections in Bosnia and Herzegovina

ABSTRACT Objectives Klebsiella spp. is a common cause of urinary tract infections (UTIs) and it is important nosocomial pathogen. There is currently little information about a prevalence of AmpC beta-lactamases in these strains. The aim of the study was to investigate a prevalence of plasmid –mediated AmpC (pAmpC) beta-lactamases in Klebsiella spp. causing UTIs in Bosnia and Herzegovina (B&H), during December 2009-May 2010. Methods Minimum inihibitory concentrations (MICs) of various antibiotics were determined by broth microdilution method according to CLSI guidelines. Double-disk synergy test and combined disk test with phenylboronic acid were used to detect ESBLs and pAmpC beta-lactamases respectively. BlaESBL, and blaAmpC genes were detected by PCR. Genetic relatedness of the strains was tested by pulsed-field gel electrophoresis (PFGE). Results ESBL. were found in 28 Klebsiella spp (22 K. pneumoniae and six K. oxytoca). Genes encoding pAmpC beta-lactamases were detected in two (7.1%) isolates, one from K. oxytoca and one from K. pneumoniae. Sequence analysis revealed blaDHA-1genes in both isolates. One isolate was obtained from Pediatric (2 years old patients) and one from Orthopedic and Traumatology Department (68 years old patient). ESBL-encoding genes were found in both isolates positive for pampC (SHV-5, and TEM-1/CTX-M-15/SHV-1, respectively). The isolate from Pediatric Department showed resistance to aminoglycosides, and third generation cephalosporins, intermediate susceptibility to cefepime, but was susceptible to fluoroquinolone and, carbapenems, while the other isolate showed high level resistance to all antibiotics (multidrug resistance), except of carbapenems. PFGE showed no genetic relatedness between the isolates. Conclusion The prevalence of pAmpC-type mediated resistance in most countries is unknown. The presence of multiple beta-lactamases was reported previously. The clonal relatedness among isolates suggests vertical spread of blaDHA-1 in Klebsiella spp. It is very important to characterize pAmpC positive isolaters of Klebsiella spp in order to prevent the spread of these multidru-resistant isolates in hospital environment. This is the first report of Klebsiella spp. isolate producing DHA-1 beta-lactamases in Bosnia and Hercegovina.