Antimicrobial resistance profiles and multidrug resistance among Escherichia coli isolates from wound samples in the University of Port Harcourt Teaching Hospital, Nigeria

Wound infections remain an important clinical challenge because antimicrobial resistance can limit treatment options. This study assessed the prevalence, antimicrobial resistance profiles, multidrug resistance (MDR), and multiple antibiotic resistance (MAR) indices of Escherichia coli isolated from wound samples at the University of Port Harcourt Teaching Hospital (UPTH), Nigeria. Wound samples were processed using standard microbiological methods, and antimicrobial susceptibility was assessed by the Kirby-Bauer disc diffusion method. Of 100 wound samples cultured, 95 yielded bacterial growth and 51 presumptively identified E. coli isolates were recovered, representing 51/95 (53.7%) of culture-positive samples. Other isolates included Klebsiella sp. (15.8%), Citrobacter sp. (10.5%), Proteus sp. (9.5%), Enterobacter sp. (6.3%), and Serratia sp. (4.2%). Among the 51 E. coli isolates, resistance was highest to Cefotaxime (100%), followed by Ampiclox, Amoxicillin-clavulanic acid, and Cefuroxime (98% each), Cefixime (96%), and Imipenem (92%); Gentamicin showed the lowest resistance (47%). Twenty-three antibiogram patterns were identified, with the most frequent pattern occurring in 13 isolates. Fifty of 51 isolates (98.04%) met the study definition of MDR. Among the 50 MDR isolates, 12.0% were resistant to three antimicrobial classes, 24.0% to four classes, 22.0% to five classes, and 42.0% to six classes. A total of 50/51 (98.04%) isolates had MAR index values greater than 0.2. The wound-associated E. coli isolates showed high levels of antimicrobial resistance and MDR. These findings indicate a substantial antimicrobial resistance burden among the isolates studied and support continued antimicrobial susceptibility testing, resistance surveillance, infection-prevention measures, and antimicrobial stewardship at UPTH. The mechanisms underlying the observed resistance were not investigated in this study and require further study.