Gene Expression Evaluation of mexT and mexF Genes of Pseudomonas aeruginosa under Antibiotic Stress

Abstract Background: Pseudomonas aeruginosa is a major cause of mortality and morbidity in those with immunodeficiencies and those who have cystic fibrosis and antibiotic resistance. Objectives: To investigate the role of genes responsible for pump efflux of antibiotics ( mexF and mexT ) and their relation to antibiotic resistance. Materials and Methods: A total of 100 clinical swabs were collected from different hospitals in Baghdad, Iraq. The identification of bacterial isolates was confirmed using the VITEK2 compact system and 16s rRNA . Drug susceptibility tests were performed by the VITEK2 compact system. Conventional polymerase chain reaction (PCR) was used for the detection of efflux pump ( mexT and mexF ) genes for the isolates. Reverse transcription (RT)-PCR was used to detect gene expression and the effect of ceftazidime and amikacin antibiotics on the mexT gene for five isolates. Results: The results of culture and biochemical tests showed that 50 isolates were P . a eruginosa . They were resistant to cefotaxime (71.43%), ceftazidime (71.43%), cefepime (71.43%), meropenem (65.71%), imipenem (62.86%), amikacin (62.86%), gentamicin (62.86%), norfloxacin (60%), and ciprofloxacin (51.43%). The result of conventional PCR showed that mexT 20 (57.1%) was positive, whereas mexF 18 (51.4%) and the results of RT-PCR indicated that all isolates exhibited downregulation of the mexT gene. Conclusion: There is a positive correlation between mexT and mexF genes and antibiotic resistance.