Role of OMP Expression in Carbapenem Resistance in Clinical Isolates of Klebsiella Pneumoniae

Abstract

       Klebsiella pneumoniae has been emerged as one of the most important causes of urinary tract infection UTI. The deficiency of porins ompK35 and ompK36 are important for the development of carbapenem-resistant K. pneumoniae. Clinical K. pneumoniae isolates has been characterized and investigated for the effect of meropenem on the ompK35 and ompK36 and their reduced expression to develop carbapenem resistance for six carbapenem resistant K. pneumoniae strains. One hundred eighty urine specimens were collected from impatiens and outpatients admitted to three hospitals in Baghdad, cultured and examined microscopically and identified by traditional biochemical tests, VITEK-2 system and molecular identification using the specific gene tyrBK. pneumoniae by polymerase chain reaction. Forty four isolates were identified as K. pneumoniae (24.4%) of the total collected bacteria causing UTI. Theantibiotic susceptibility and Minimal inhibitory concentration (MIC) test of 44 K. pneumoniae isolates towards meropenem antibiotic was examined using disc diffusion method and E-test method respectively, results showed that 6 (13.6%) were resistant to meropenem with MIC value (4-8 μg/ml), 35 (79.5%) were sensitive with MIC value (0.125-0.5μg μg/ml), while 3(6.8%) isolates were of intermediate resistant with MIC of (2 μg/ml). Poringene expression ompK35 and ompK36 genes was conducted using real-time quantitative PCR assay. Gene expression fold were recorded for three study groups, antibiotic sensitive group as control group, antibiotic resistant group before treatment with meropenem and resistant group after treatment with meropenm with a concentration of (1μg/ml) for all resistant isolates. The highest value of gene expression fold in ompK35 gene was recorded for the sensitive group (1.00), andthe untreated meropenem group gene expression fold of ompK35 (0.95), while the lowest gene expression fold of ompK35 gene was for meropenem treated group (0.055).The highest value of gene expression fold in ompK36 gene was recorded for the untreated meropenem group (1.33), and the gene expression fold of sensitive group of ompK36 (1.00), while the lowest gene expression fold of ompK36 gene was for meropenem treated group (0.007)depending on 2^-Δct   method. When depending on 2^-ΔΔct method, Gene expression fold had slight difference.