Research in Medicine

Background: The increasing emergence of antimicrobial resistance among gram negative bacteria especially
Enterobacteriaceae has become a global problem. Klebsiella pneumoniae is an opportunistic pathogen, which
recently due to causing broad spectrum of disease and antibiotic resistance has been lionized. Efflux pumps are one
of the antibiotic resistance mechanisms, which were introduced in this bacteria. Therefore, the aims of this study
were detection of oqxA, oqxB, acrA and acrB genes, evaluation of expression level of oqxA and acrA genes and
determination of antibiotic resistance patterns among Klebsiella pneumoniae isolated at Tehran hospitals.
Materials and Methods: In this descriptive study 83 Klebsiella pneumoniae were collected from patients attending
to three hospitals in Tehran. Antibiotic susceptibility test was performed by disk diffusion method. The presence of
oqxA, oqxB, acrA and acrB resistance genes was detected by PCR. The CCCP was used as efflux pump inhibitor and
the oqxA, acrA genes expression level was analyzed by using real-time PCR.
Results: The most of strains showed to have OqxAB (96%) and AcrAB (97%) pumps. The use of efflux pump inhibitor
showed different results for ciprofloxacin MIC. Real-time PCR assay showed higher expression level of OqxAB (2.3
folds) and AcrAB (4 folds) pumps in resistant strains.
Conclusion: The existence of antibiotic resistance genes, increasing of Klebsiella pneumoniae strains, which become
resistant to common antibiotics and nosocomial infections, highlights the need for particular detection, prevention
and control of spread of resistant bacteria.