Active Efflux-Medicated Drug Resistance In Acinetobacter Baumannii

Objective To investigate the current situation of antimicrobial resistance of the 54 isolates of Acinetobacter baumannii and explore the distribution of the adeB,adeJ,abeM gene in the 54 isolates and the relationship between the drug-resistance and the mRNA expression levels of the three genes. Methods To collect the 54 clinical isolates of Acinetobacter baumannii from the first affiliated hospital of Kunming Medical college. Disk diffusion testing were used to detemine the susceptibility of 21 antimicrobial against 54 isolates of Acinetobacter baumannii . The adeB,adeJ,abeM gene and their mRNA expression in Acinetobacter baumannii isolates were detected by PCR and RT-PCR, respectively.ResultsThe results of Acinetobacter baumannii resistance testing1. Sixteen kinds of antimicrobial susceptibility results revealed: Gentamicin (GEN), trimethoprim / sulfamethoxazole (SXT), piperacillin (PIP), ceftriaxone (CRO), tetracycline (TCY), ceftazidime (CAZ), cefotaxime (CTX), tobramycin (TOB), amikacin (AMK) is in the resistance rate of about 70% . Imipenem (IMP), meropenem (MEM), cefoperazone / sulbactam (CSL), still maintain a high sensitivity. Five kinds of resistance patterns including 5 class antibacterial agent which resistant isolates 15 (27.8%), 4 class medicine-resistant isolates 15 (27.8%), 2 class drug-resistant strains 9 (16.7%), resistance to a class medicine isolates 9 (16.7%), sensitive isolates 6 (11.1%).2. The resistance rate of 54 isolates of Acinetobacter baumannii to substrate of three efflux pumps revealed: Lincomycin (LIN) 100.0%, rifampicin (RIF) 98.2%, chloramphenicol (CHL), gentamicin (GEN) 75.0%, tetracycline (TET) 71.4%, erythromycin (ERY) 64.3 %, amikacin (AMK) 53.6%, tobramycin (TOB) 53.6%, ciprofloxacin (CIP) 50.0%, levofloxacin (LVX)41.1%.Efflux protein coding genes adeB, adeJ, abeM of PCR amplification and quantitative RT-PCR.1. adeB gene was detected in 49 isolates of the 54 . adeB gene was not detected in 5 isolates including 4 sensitive isolates. The mRNA expression level of efflux protein coding gene adeB of MDR-AB and sensitive isolates were significantly different (P<0.05) .Efflux pump substrate: gentamicin, tetracycline, ciprofloxacin, levofloxacin, tobramycin, and amikacin in this study. The mRNA expression levels of gene adeB of Resistant isolates and sensitive isolates were significantly different (P<0.05) .2. In this study adeJ was detected in the 54 isolates . Both types of isolates of antibiotic resistant and sensitive isolates of adeJ gene the mRNA expression levels were not significantly different in both (P>0.05) .3. abeM gene were detected in 54 isolates. The mRNA expression levels of efflux protein coding genes abeM of Resistant isolates and sensitive isolates was significantly different(P<0.05). The mRNA expression levels of abeM.gene of ciprofloxacin, levofloxacin in resistant isolates and sensitive isolates were significantly different (P<0.001) . Conclusion The Situation of resistant of Acinetobacter baumannii is severe. AdeB,adeJ and abeM gene is ubiquitous in Acinetobacter baumannii clinical isolates. Efflux pump AdeABC,AbeM should be a role in the mechanism of Acinetobacter baumannii drug-resistance.