Identification of Efflux Pump Mutations in Pseudomonas aeruginosa from Clinical Samples

Abstract

Efflux pumps are a specialized tool of antibiotic resistance used by Pseudomonas aeruginosa to expel antibiotics. The current study was therefore conducted to examine the expression of MexAB-OprM and MexCD-OprJ efflux pump genes. In this study, 200 samples were collected from Khyber Teaching Hospital (KTH) and Hayatabad Medical Complex (HMC) in Peshawar, Pakistan. All the isolates were biochemically identified by an Analytical Profile Index kit and at the molecular level by Polymerase Chain Reaction (PCR) utilizing specific primers for the OprL gene. A total of 26 antibiotics were tested in the current study using the guidelines of the Clinical and Laboratory Standard Institute (CLSI) and high-level resistance was shown to amoxicillin-clavulanic acid (89%) and low-level to chloramphenicol (1%) by the isolates. The antibiotic-resistant efflux pump genes MexA, MexB, OprM, MexR, MexC, MexD, OprJ, and NfxB were detected in 178 amoxicillin-clavulanic acid-resistant isolates. Mutations were detected in MexA, MexB, and OprM genes but no mutation was found in the MexR gene as analyzed by I-Mutant software. Statistical analysis determined the association of antibiotics susceptibility patterns by ANOVA: Single Factor p = 0.05. The in silico mutation impact on the protein structure stability was determined via the Dynamut server, which revealed the mutations might increase the structural stability of the mutants. The docking analysis reported that MexA wild protein showed a binding energy value of −6.1 kcal/mol with meropenem and the mexA mutant (E178K) value is −6.5 kcal/mol. The mexB wild and mutant binding energy value was −5.7 kcal/mol and −8.0 kcal/mol, respectively. Efflux pumps provide resistance against a wide range of antibiotics. Determining the molecular mechanisms of resistance in P. aeruginosa regularly will contribute to the efforts against the spread of antibiotic resistance globally.

The Effect of Antibiotic Treatment and Gene Expression of Mex B Efflux Transporters on the Resistance in Pseudomonas Aeruginosa Biofilms

“…Our data has shown that MexB seems to contribute the most within the MexAB-OprM efflux pump system towards the antibiotic-resistance phenotype. Also, studies on multidrug resistant P. aeruginosa strains isolated from hospitals by Bialvaei et al reported that the overexpression of mexB and mexY was significantly more prevalent in the studied strains, with a significant correlation with antibiotic resistance [7,33]. Altogether, the efflux pumps play important roles in increasing the resistance towards different antibiotics, but the role of other agents and mechanisms in the evolution of resistance should not be ignored.…”

“…The presence of these efflux pumps poses a significant challenge in managing multidrugresistant P. aeruginosa infections, emphasizing the need for a comprehensive understanding of their underlying mechanisms. Moreover, exploring the development of efflux pump inhibitors holds promise as a potential adjunctive therapy to address the complexities associated with P. aeruginosa infections, particularly those involving multidrug-resistant strains [5][6][7].…”