Phenotypic and genotypic detection of antibiotic resistance among Pseudomonas aeruginosa isolates from orthopedic wounds from Chukwuemeka Odumegwu Ojukwu University Teaching Hospital (Coouth), Awka Anambra Nigeria

Abstract

Pseudomonas aeruginosa is well known orthopedic wounds-associated bacterial pathogen, responsible for prolonged wound treatment, due to its resistance, mediated by different types of extended-spectrum beta-lactamases (ESBL). The present study was undertaken to find the prevalence of extended-spectrum β lactamase (ESBL), Metallo-β lactamase (MBL), and AmpC β lactamase in P. aeruginosa isolated from orthopedic wound samples. Wound swabs were processed and P. aeruginosa was identified by standard protocols. The Kirby-Bauer disc diffusion method was used in ascertaining the antibiotic sensitivity of the isolates. Special screening and confirmatory tests were performed for the phenotypic and genotypic detection of resistance. The resistance rate to gentamicin, ofloxacin, ciprofloxacin and ceftazidime were 2.6%, 2.6%, 2.6, and 5.1% respectively. P. aeruginosa expressed very high resistance to amoxicillin (97.4%), nitrofurantoin (100%), and two of the 3rd generation cephalosporins: cefuroxime (100%), and cefixime (100%). The aminoglycoside and the quinolones were the most effective drugs against the P. aeruginosa isolates with susceptibilities of 97.4% and 94.9% respectively. Out of the 38 isolates of P. aeruginosa, 11 (28.9%) and 14 (36.8%) were ESBL and MBL positive, respectively. The blaTEM genes were the only prevalent genes detected in all 38 (100%) isolates and mediated the phenotypic and genotypic resistance observed. MBL production was observed in 14 (36.8%) while AmpC and co-expression of genes were not observed. The blaTEM genotypic resistance was observed to be common among the isolates. This calls for great concern and continuous monitoring of antimicrobial resistance with the implementation of stringent mediation practices toward infection prevention and control.