Extended-Spectrum ꞵ-Lactamases-Producing Escherichia coli from Orthopaedic Wounds
Keyword : Orthopaedic wounds, Escherichia coli, Imipenem, antibiotic resistance, Nigeria
Author(s) : Okwuonu, A.C And Chukwura, E.I
Abstract : The study, aimed at determining the prevalence and antibiotic resistance pattern of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli from wound infections was done between July 2017 and February 2018 at an Orthopaedic Hospital in South-Eastern Nigeria. Two hundred wound swabs collected using sterile swab sticks were aseptically inoculated primarily on MacConkey and blood agar plates, respectively and uniformly streaked at interval with flaming sterile wire loops. Incubation was at 37°C for 24 hours under aerobic and in microaerophilic conditions for bacterial growth. Antibiotic susceptibility test was evaluated by Kirby-Bauer disc diffusion method. ESBL-producing forty-nine (24.5%) E. coli isolates were obtained from the 200 swab samples. Forty-five (22.5%) of E. coli isolates subjected to Double disc synergy testing (DDST), confirmed the 18 isolates to be ESBL-producers. The Polymerase chain reaction (PCR) detected three genes Temoniera, Sulfhydryl variant, and Cefotaximase, mostly carried in E. coli plasmid, thus confirming the presence of E. coli. Elderly patients and males had highest prevalence of wound infections, especially on legs. Imipenem 5 (10.2%) was most active on E. coli isolates but there was a high frequency of multidrug-resistant pathogenic E. coli. Antibiotic susceptibility test showed that E. coli was highly resistant to Cefpirone 41 (83.7%), Cefoxitin37 (79.6%), Ceftazidime 35 (72.4%), Amoxicillin/Clavulanic acid 45(91.8%), Cefotetan 44 (89.8%), Cefotaxime 43 (88.8%), and Aztreonam 32 (66.3%). Indiscriminate use of third generation cephalosporins and monobactams must therefore be avoided. Currently, Imipenem has proved to be a better option for the treatment of orthopaedic wounds infections with E. coli.