Genotypic and phenotypic characterization of determinants that mediate antimicrobial resistance in strains of clinical origin in South-Western Nigeria.

Background: Multidrug resistant bacterial pathogens employ different mechanisms in evading the action of antibiotics. Multidrug resistance is wide spread among strains of implicated in several infections including urinary tract infections, gastrointestinal infections, meningitis and bacteraemia.

Aim/objective: This study investigates the antibiotic resistance profile, efflux pump activity and biofilm formation ability of strains isolated from clinical samples.

Methods: A total of 32  strains isolated from clinical samples were characterized and subjected to antibiotic susceptibility testing using standard methods. Isolates were screened phenotypically for biofilm formation and efflux pump activity. While molecular detection of genes encoding curli fimbriae and efflux pump activity was done by PCR.

Results: All 32 (100%) isolates were resistant to ceftazidime, cefuroxime, cefixime, amoxicillin-clavulanate, ofloxacin and ciprofloxacin. While 30 (93.8%) were resistant to gentamicin, 27 (84.4%) were resistant to cefepime and the least resistance of 15.6% was to imipenem. Efflux pump encoding gene was detected in 13(40.6%) of the isolates, while 1(3.1%) harboured gene. gene was not detected in any of the isolates. Seven (21.9%) of the isolates were strong biofilm formers, while 5 (15.6%) and 20 (62.5%) were moderate and weak biofilm formers respectively. gene was detected in all isolates.

Discussion: High antibiotic resistance of strains observed in this study is of public health significance. . It is therefore important to scale up efforts in regular monitoring of antibiotic resistance in both community and hospital settings.