RESUMO
P. aeruginosa remains an important cause of life-threatening bloodstream infection in immunocompromised patients, particularly those with hematologic malignancies complicated by neutropenia. One of the most worrisome characteristics of P. aeruginosa consists is its low antibiotic susceptibility. This low susceptibility is attributable to concerted action of chromosomally-encoded multidrug efflux pumps genes. These genes are often controlled by regulatory gene located on the same operon of efflux pump. One of particular significance is the MexAB-OprM efflux system, which is expressed constitutively, thereby contributing to the well-known intrinsic resistance of this organism to multiple antimicrobials. To detect the occurrence of mexAB-OprM operom on the chromosomes of septicemic P. aeruginosa[SPA]. This study was include 53 Pseudomonas aeruginosa isolates isolated from patients their ages ranging from 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 and gastrointestinal neoplasms patients. Nine [17%], 3[5.7%], 6 [11.3%] and 3[5.7%] from urogenital neoplasms, breast cancer patients, septicemic patients due to burn infections and neonatal septicemia respectively. Chromosomal DNA was extracted from SPA isolates and subjected to PCR to amplify three genes of mexAB-OprM efflux pump. Multiplex PCR of mexAB-OprM efflux pump genes revealed that 53 [100%] were positive to all three genes of operon, mexA, mexB and the regulatory gene, mexR. P. aeruginosa can cause septicemia in cancer patients and other compromised patients, like patients suffering from extensive burns and neonatal infants. mexAB-OprM efflux pump genes are a chromosomal encoded genes and can be used as a markers in identification of SPA by molecular methods. These genes can be used individually or collectively in rapid identification of SPA, and rapid detection for mexAB-OprM efflux pump occurrence on their chromosomes