Antimicrobial Resistance Profiles of Biofilm-forming E. coli, Pseudomonas Aeruginosa, and Klebsiella Pneumoniae Isolates from Chronic Wound Infection.

Background

Antimicrobial-resistant (AMR) bacteria in chronic wound infections contribute to delayed healing, prolonged treatment, increased mortality, and rising healthcare costs. In resource-limited settings like Abakaliki, Southeastern Nigeria, improper antibiotic use worsens wound infection management. This study evaluates the antimicrobial resistance profiles of biofilm-forming E. coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae and identifies antimicrobial resistance genes in chronic wound infections.

Materials and Methods: From February to September 2024, pus samples from chronic wounds (≥12 weeks) were collected at Alex Ekwueme Federal University Teaching Hospital, Abakaliki. Bacteria were isolated using standard microbiological techniques, biofilm formation was assessed via Congo Red Agar (CRA), and antimicrobial resistance genes were detected through Polymerase Chain Reaction (PCR).

Results: Of 600 samples analyzed, 476 (79.3%) had bacterial growth: E. coli (31.8%), P. aeruginosa (26.2%), and K. pneumoniae (21.3%). Biofilm formation was observed in 41.8% of the isolates, predominantly P. aeruginosa (19.8%), followed by E. coli (12.2%) and K. pneumoniae (9.8%). All isolates were resistant to amoxicillin–clavulanic acid (100%). E. coli showed high resistance to ceftriaxone (86.3%) and ampicillin (87.6%), while P. aeruginosa resisted colistin (100%) and cefotaxime (84.0%). K. pneumoniae exhibited resistance to cefoxitin (67.8%). No resistance was found against imipenem, ofloxacin, and gentamicin. E. coli carried blaCTX-M-9 (63%), blaTEM (54.7%), and blaSHV (41.1%), all P. aeruginosa harbored blaCTX-M-9, blaSHV and blaTEM (100 %) while K. pneumoniae harbored blaCTX-M-9 (100%) and blaTEM (49.1%). The mcr-1 gene was present in all isolates.

Conclusion: The AMR burden in Abakaliki presents a significant challenge in treating chronic wound infections. Addressing this issue requires antimicrobial stewardship, infection control, routine surveillance, education, and research to improve regional wound infection management.