Evaluation of the Frequency of Broad-Spectrum Beta-Lactamases in Urinary Isolates of Drug-Resistant Klebsiella pneumoniae by Genotypic and Phenotypic Methods

 There are several reports regarding the increase and growing prevalence of ESBLs producing organisms from different regions in the country. Considering that Klebsiella pneumoniae includes a significant percentage of hospital infections, therefore, knowing the pattern of resistance and sensitivity of this bacterium to beta-lactam antibiotics plays a significant role in the treatment and control of infections caused by this bacterium. As a result, the aim of the present study was to determine and evaluate the frequency of beta-lactamases The broad spectrum of Klebsiella pneumoniae urinary isolates was drug-resistant by genotypic and phenotypic methods.

In the present cross-sectional descriptive study conducted in 2018, 100 strains of Klebsiella pneumoniae were isolated from urine samples of patients with urinary tract infection from Al-Zahra Hospital, Isfahan. Klebsiella pneumoniae strains were identified and confirmed using standard biochemical tests. Antibiotic sensitivity pattern was investigated by disk diffusion method based on CLSI criteria. To perform the phenotypic verification test of broad-spectrum β-lactamase producing strains, the combined disc method was used based on CLSI criteria. PCR test was done with specific primers to identify blaSHV and bla TEM. The collected data were analyzed using one-way and independent one-way analysis of variance statistical tests.

Among 100 isolates related to urinary tract infection, 33 isolates indicated resistance to at least 4 antibiotics, the highest resistance to cefotaxime antibiotic (38%) and the least antibiotic resistance to cotrimaxazole (22%). The results of combined disk indicated that 10 isolates (86.8%) were broad-spectrum β-lactamase producers. Among them, 7 isolates (70%) had the SHV gene and the other 3 isolates did not have any of the TEM and SHV genes.

The results indicated a higher frequency of ESBLs and correspondingly a higher prevalence of antibiotic resistance in Klebsiella pneumoniae bacteria isolated from urinary tract infections.