@Article{, title={Occurrence of MexAB-OprM Efflux Pump Operon on Septicemic Pseudomonas Aeruginosa Chromosome}, author={Ibtesam Ghadban Auda Al-Grawi}, journal={Iraqi Postgraduate Medical Journal المجلة العراقية للاختصاصات الطبية}, volume={11}, number={1}, pages={97-102}, year={2012}, abstract={ABSTRACT:BACKGROUND:P. aeruginosa remains an important cause of life-threatening bloodstream infection inimmunocompromised patients, particularly those with hematologic malignancies complicated byneutropenia. One of the most worrisome characteristics of P. aeruginosa consists is its lowantibiotic susceptibility This low susceptibility is attributable to concerted action ofchromosomally-encoded multidrug efflux pumps genes. These genes are often controlled byregulatory gene located on the same operon of efflux pump. One of particular significance is theMexAB - OprM efflux system, which is expressed constitutively, thereby contributing to thewell-known intrinsic resistance of this organism to multiple antimicrobials.OBJECTIVE:To detect the occurrence of mexAB-OprM operom on the chromosomes of septicemic P.aeruginosa(SPA).METHODS:This study was include 53 Pseudomonas aeruginosa isolates isolated from patients their ages rangingfrom two days to 73 years,28 males and 25 females. Some of the isolates were isolated from acute,15(28.3%), and chronic, 7 (13.2%), leukemic patients, 5 (9.4%) from each lymphoma andgastrointestinal neoplasms patients. Nine (17%), 3(5.7%), 6 (11.3%) and 3(5.7%) from urogenitalneoplasms, breast cancer patients, septicemic patients due to burn infections and neonatalsepticemia respectively. Chromosomal DNA was extracted from SPA isolates and subjected to PCR toamplify three genes of mexAB-OprM efflux pump.RESULTS:Multiplex PCR of mexAB-OprM efflux pump genes revealed that 53 (100%) were positive to all threegenes of operon, mexA, mexB and the regulatory gene, mexR.CONCLUSION:P. aeruginosa can cause septicemia in cancer patients and other compromised patients, like patientssuffering from extensive burns and neonatal infants. mexAB-OprM efflux pump genes are achromosomal encoded genes and can be used as a markers in identification of SPA by molecularmethods. These genes can be used individually or collectively in rapid identification of SPA, and rapiddetection for mexAB-OprM efflux pump occurrence on their chromosomes.

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