Prevalence of Metallo-β-Lactamase Genes in Clinical Isolates of Klebsiella pneumoniae in Health Care Centers in Mazandaran Province

Background: Klebsiella pneumoniae is one of the most important causes of opportunistic infections, includinglobar pneumonia, urinary tract infection (UTIs), and wound infection. Treatment of disease caused by thisbacterium has also become a challenge, as many strains are resistant to all β-lactam antibiotics. Metallo-β-lactamases hydrolyze most β-lactam antibiotics, especially carbapenems, but cannot inactivate monobactams.This study aimed to determine the prevalence of Metallo-β-lactamase genes (blaIMP, blaVIM, and blaNDM) in K.pneumoniae isolated from clinical specimens.Methods: Clinical samples were collected from hospitals of Mazandaran province. Among 500 clinical samplescollected, only 40 Klebsiella pneumoniae isolates were detected by culture and biochemical tests. Antimicrobialsusceptibility testing was performed on all isolates by the Kirby-Bauer method. The polymerase chain reaction(PCR) technique was used for the identification of blaIMP, blaVIM, and blaNDM genes.Results: Antibiogram by disk diffusion method showed that 21 (52%) and 19 (48%) isolates were classified asimipenem resistant and sensitive, respectively. Of all the samples, 30 (75%), 7 (17.5%), and 36 (90%) containedblaVIM, blaIMP, and blaNDM genes, respectively. The co-existence of the blaVIM and blaNDM genes was observed in22 (55%) isolates. The presence of both blaIMP and blaNDM genes was confirmed in 2 (5%) of the isolates. Fourisolates (10%) had blaNDM, blaIMP, and blaVIM genes simultaneously, but none of these genes were present in oneisolate (2.5%).Conclusions: This study showed that the prevalence of metallo-β-lactamase genes in K. pneumoniae isolatedfrom clinical specimens is very high, so it is recommended that physicians treat patients based on phenotypicand genotypic characteristics.

Prevalence of Metallo-β-Lactamase Genes in Clinical Isolates of Klebsiella pneumoniae in Health Care Centers in Mazandaran Province Keywords:

Metallo-β-lactamase , Resistance gene , Klebsiella pneumoniae , Clinical samples