Antimicrobial Resistance Patterns, Resistance and Virulence Genes in Pseudomonas aeruginosa from Hospitalized Patients in Lagos, Nigeria

Abstract

Background: Pseudomonas aeruginosa has been a major cause of healthcare-associated infections due to increasing antimicrobial resistance. This study investigates the prevalence, antimicrobial resistance and virulence determinants in P. aeruginosa from patients.

Materials and Methods: A total of 550 clinical samples were collected from patients attending public hospitals between August 2022 and July 2024 in Lagos. The samples were processed, and Pseudomonas isolates were identified. Furthermore, the isolates were subjected to antimicrobial susceptibility testing (AST) using standard protocols. Real-time Polymerase Chain Reaction was used with specific primers to detect resistance (blaOXA-48, blaVIM) and virulence (oprL, toxA) gene markers

Results: The prevalence of 6.7% (37/550) Pseudomonas species was recorded, consisting of 23 P. aeruginosa, 11 P. alcaligenes, and 3 P. maltophilia. A higher prevalence (5.2%) occurred in females than males, with the age group 31–49 years mostly implicated. There were no statistically significant associations between age or sex and infections (p > 0.05) recorded. Pseudomonas aeruginosa was 100% resistant to trimethoprim-sulfamethoxazole, amoxicillin-clavulanic acid, colistin and tigecycline, 78.3% to meropenem, and 73.9% to ceftazidime. Eighteen distinct resistance patterns were observed. Carbapenemase production was detected in 73.9% of P. aeruginosa, extended-spectrum β-lactamase (ESβL) in 26.1%, and AmpC β-lactamase in 13%. Interestingly, 100% of P. aeruginosa expressed oprL, and 95.7% expressed toxA, while 13% of P. aeruginosa carried blaOXA-48 and blaVIM, from septiceamia cases.

Conclusion: Multidrug-resistant Pseudomonas aeruginosa strains carrying blaOXA-48 and blaVIM and virulence genes oprL and toxA are currently circulating in Lagos. A need for antimicrobial stewardship and molecular surveillance to mitigate the effects.