AdeABC Efflux Pump Genes in Multidrug ResistantAcinetobacter baumanniiIsolates

Abstract

Objectives: Acinetobacter baumannii is an opportunistic nosocomial pathogen and a cause of severe infections in hospitalized patients, owing to its ability to acquire drug resistance by the efflux pump mechanism. The current study investigated the detection and prevalence of efflux pump genes (AdeABC) in multidrug resistant A. baumannii isolates and the role of these genes in multidrug and carbapenems resistance. Methods: This study was conducted on 84 multidrug resistant and 13 carbapenem-susceptible A. baumannii isolates obtained from burn and wound infections in Baghdad hospitals, Iraq. The AdeABC genes were detected by polymerase chain reaction (PCR) assay. Phe-arg-beta-naphthylamide (PAβN)-based method was used for determination of efflux pump activity. Results: This study showed high prevalence of efflux pump genes in our local isolates. The AdeB gene was present in all multidrug resistant isolates (100%) while AdeRS gene was found in 95.2%, AdeC gene in 83.3% and AdeA gene in 77.4%. By comparing the prevalence of these gene in carbapenem-susceptible isolates, it was demonstrated that the gene AdeB was absent in all susceptible isolates, also the regulatory gene AdeRS was not found in most of these isolates, while the other genes (AdeA and AdeC) were detected in most carbapenem-susceptible isolates. Susceptibility of isolates to Amikacin, Gentamicin, Ciprofloxacin, Levofloxacin, Tetracycline and Tigecycline was highly increased in the presence of efflux pump inhibitor, so that, PAβN reduced the minimum inhibitory concentrations (MICs) by 4 to 32 folds. Also, MICs of carbapenems were reduced in the presence of the inhibitor by two to eight folds, while the MICs of colistin were not affected. Conclusions: AdeABC efflux system plays a vital role in multidrug resistance in clinical A. baumannii isolates. It was noted that the most important gene responsible for multidrug resistance within this system was the AdeB gene especially in carbapenems resistance.

Study of MIC of silver and zinc oxide nanoparticles, strong and cost-effective antibacterial against biofilm-producing Acinetobacter baumannii in Shiraz, Southwest of Iran

“…However, in the study of Angoti et al, as in the present study, the frequency of adeM (98.3%) and adeA (88.5%) genes has been reported more [ 16 ]. In the study of Ranjbar et al and also in the study of Jassim et al, they found the highest frequency to be related to the adeA and adeC gene [ 33 , 34 ]. In this study, it was found that the genes that are more abundant are related to isolates whose growth was inhibited by a higher concentration of nanoparticles, and the abundance of these genes was related to the concentration of nanoparticles.…”

Genome-wide association study of antibiotic resistance in clinical Burkholderia pseudomallei strains from Hainan province, China

“…Based on pan-GWAS analysis of the whole genome of B. pseudomallei, the genes signi cantly associated with the AMC resistant phenotype were the known resistant genes group_2287 (ArpC) and group_4353 (MdtC). Outer membrane e ux pump proteins play a signi cant role in various resistance mechanisms acquired by Acinetobacter baumannii [23,24]. The genes signi cantly associated with the DOX-resistant phenotype were group_693 (OprM), group_2285 (OprM), and group_22059 (MexB).…”

Role of Efflux Pumps in Reduced Susceptibility to Tigecycline among Clinical Isolates of Acinetobacter baumannii

“…Studies conducted earlier have also reported, adeB to be most prevalent efflux genes among adeABC. [ 15 - 17 ] Function of adeA is to act as a membrane fusion protein, adeB captures substrates in the inner membrane of phospholipids bilayer or the cytoplasm, then transports the substrates by adeC (membrane channel protein). The adeRS bicomponent regulation system consists of sensor kinase adeS and responsive regulator adeR.…”