Efflux pump genes and antimicrobial resistance of Pseudomonas aeruginosa strains isolated from lower respiratory tract infections acquired in an intensive care unit

Abstract

The aim of this study was to determine the antimicrobial resistance rates and the resistance genes associated with efflux pumps of Pseudomonas aeruginosa strains isolated from the patients who acquired lower respiratory tract infection (LRTI) in intensive care unit (ICU). Fifty P. aeruginosa strains isolated from the lower respiratory tract specimens of the patients who acquired LRTIs in ICU were included in this study. P. aeruginosa strains were isolated from tracheal aspirate (27), bronchoalveolar lavage (14) and sputum (9). The susceptibilities of the isolates were investigated by the disk diffusion method. Multiplex PCR assay was carried out for the detection of 13 antibiotic-resistance genes. Antimicrobial resistance rates of the isolates were found high and the highest resistance rate of the isolates studied was determined against to mezlocillin (50%) followed by norfloxacin (48%), ciprofloxacin (46%), meropenem (40%). Fourty-three isolates (86%) were determined to carry one and more resistance genes. NfxB gene was most often determined in the genes that were investigated. The significant relation between the resistance to cefepime, piperacilline/tazobactam and the mexC gene, that between the resistance to mezlocillin, piperacilline/tazobactam, ceftazidime, cefepime and ampC genes, and that between the resistance to ciprofloxacin, norfloxacin and oprJ, oprN and nfxB genes was identified. Resistance caused by genes for carbapenemases, aminoglycoside-modifying enzymes and other mechanisms were not identified in this study. Understanding the prevalence and mechanism of antimicrobial resistance in P. aeruginosa may help to select empirical therapy for nosocomial LRTIs due to P. aeruginosa in our ICU.

Molecular Detection of Aminoglycoside Resistance Mediated by Efflux Pump and Modifying Enzymes in Pseudomonas Aeruginosa Isolated From Iraqi Hospitals

“…Figure (4) shows agarose gel electrophoresis for two efflux system genes(mexX and mexY). In the study of Cabot et al (28) they showed that the prevalence rate of mexY gene without over expression was 81.5% and this result is not in line of the current study, while Ozer et al (29) illustrated that the prevalence rate of mexX was 4% and this result not agreed with the current study. The genes coding for the modifying enzymes either present alone or in combination between two genes or three genes but can be seen none of the isolates in the current study was observed to contain the 4 detected genes.…”

Genetic Variations in MexAB-OprM Efflux Pump Regulators and Their Association with Antibiotic Resistance and Sequence type in Clinical and Epidemiologically High-risk Clones of Pseudomonas Aeruginosa.

“…Similar results were reported by Arabestani et al, (2015), who observed a signi cant positive correlation between pump activity and antimicrobial resistance [45]. Ozer et al, (2012) reported a consistent positive correlation between MexAB-OprM expression and multidrug resistance in 50 P. aeruginosa clinical strains [46]. However, in our study, of the P. aeruginosa strains that showed MexAB-OprM activity (phenotypic positive-strains), only in 52.9% the MexAB-OprM e ux pump was the most likely cause of resistance (+), in the remaining 47% of the strains the MexAB-OprM e ux pump was contributing to the resistance (*), which demonstrated that although the MexAB-OprM pump shows positive activity and contributes to resistance, this is not the only mechanism of resistance in these strains [13].…”

Efflux pump regulatory genes mutations in multidrug resistance Pseudomonas aeruginosa isolated from wound infections in Isfahan hospitals

“…[5] RND pumps consist of three subunit including membrane fusion protein (MFP), an outer membrane factor (OMF), and a cytoplasmic membrane transporter. [56] MexAB-OprM and MexCD-OprJ, which are members of RND efflux pumps family, have the wide substrate of antibiotics such as, β-lactam class (aztreonam, ceftazidime) and fluoroquinolones. [7] Active efflux pumps decrease intracellular concentration of drug by pumping it to out.…”