Evaluation of efflux pump activity and biofilm formation in multidrug resistant clinical isolates of Pseudomonas aeruginosa isolated from a Federal Medical Center in Nigeria

Abstract

Background Pseudomonas aeruginosa an opportunistic pathogen, is widely associated with nosocomial infections and exhibits resistance to multiple classes of antibiotics. The aim of this study was to determine the antibiotic resistance profile, biofilm formation and efflux pump activity of Pseudomonas strains isolated from clinical samples in Abeokuta Ogun state Nigeria. Methods Fifty suspected Pseudomonas isolates were characterized by standard biochemical tests and PCR using Pseudomonas species -specific primers. Antibiotic susceptibility testing was done by the disc diffusion method. Efflux pump activity screening was done by the ethidium bromide method and biofilm formation assay by the tissue plate method. Genes encoding biofilm formation (pslA & plsD) and efflux pump activity (mexA, mexB and oprM) were assayed by PCR. Results Thirty-nine Pseudomonas spp. were identified of which 35 were Pseudomonas aeruginosa and 4 Pseudomonas spp. All 39 (100%) Pseudomonas isolates were resistant to ceftazidime, cefuroxime and amoxicillin-clavulanate. Thirty-six (92%), 10(25.6%), 20 (51.2%), 11(28%) and 9(23%) of the isolates were resistant to nitrofurantoin, imipenem, gentamicin, cefepime and aztreonam respectively. All the isolates had the ability to form biofilm and 11 (28%) of them were strong biofilm formers. They all (100%) harboured the pslA and pslD biofilm encoding genes. Varied relationships between biofilm formation and resistance to ciprofloxacin, ofloxacin, cefixime, gentamicin, imipenem, and aztreonam were observed. Only 23(59%) of the Pseudomonas isolates phenotypically exhibited efflux pump activity but mexA gene was detected in all 39 (100%) isolates while mexB and oprM genes were detected in 91%, 92%, and 88% of strong, moderate and weak biofilm formers respectively. Conclusion Multidrug resistance, biofilm and efflux pump capabilities in Pseudomonas aeruginosa have serious public health implications in the management of infections caused by this organism.

Antibiotic Resistance, Biofilm Formation and Detection of mexA/mexB Efflux-Pump Genes Among Clinical Isolates of Pseudomonas aeruginosa in a Tertiary Care Hospital, Nepal

“…All MDR P. aeruginosa isolates showed strong to weak biofilm formation in the current study. This finding echoes with the study done in Nigeria (46); however, a significant lower incidence (33.7%) of biofilm forming P. aeruginosa was reported in the study done in India (47). Biofilms embedded bacteria are difficult to eradicate by conventional antibiotic therapy as bacterial cells living inside biofilms are more tolerant towards antibiotics than their planktonic counterparts (48).…”

Molecular detention of efflux pumps in Pseudomonas aeruginosa obtained from different clinical cases

“…These beams are similar to the expected size, which is approximately 247 base pairs, when compared with the results reached (Dumas et.,al 2006). The current results of this study showed that 7 isolates (34.75%) of the tested isolates of the study have the oprM gene, and the rest of the isolates do not have this gene, and this is similar to what was reached by Abbas and his group (2018) where the percentage of presence of the gene was 40.5%, and similar to what was reached Murugan and his group (2018) where the gene presence was 35%, while our results contradicted what Abdallah and his group (2021) found, where the gene presence was 8.6%. As the oprM protein has a very important role in the flow of antibiotics outside the bacterial cell (Zgurskaya and Nikaido, 2000;Masuda et al, 2000;Chuanchuen et al, 2001).…”

“…The results of this study showed that 15 isolates (93.75 %) of the tested study isolates possess the mex A gene, and thus our results are in agreement with the findings of Ugwuanyi and his group (2020) as the mexA gene was 90% present, while the presence of the mexA gene was close to As reached by Al-Grawi and his group (2012), Tomas and his group (2010), Abbas and his group (2018), where the percentages were 100%, 88.2%, 100%, respectively. While the percentage of the gene's presence contradicted what was reached (Al-Obaidi, 2015) in his study, where the percentage reached by it was (68.8%), as well as what was reached by Abdallah and his group (2021), where the percentage of the gene was 54%.…”

Resistance Is Not Futile: The Role of Quorum Sensing Plasticity in Pseudomonas aeruginosa Infections and Its Link to Intrinsic Mechanisms of Antibiotic Resistance

“…Biofilms confer resistance to numerous antibiotics. A study of nearly forty multidrugresistant P. aeruginosa isolates in Nigeria identified 50% resistance to gentamicin, and approximately 30% resistance to imipenem, aztreonam, and cefepime [137]. The cohort was unanimously resistant to other cephalosporins, penicillin, ciprofloxacin, and nitrofu-rantoin.…”