Exploring the genetic diversity and the association of drug resistance and biofilm production in Acinetobacter baumannii strains isolated from burn wound infections

Acinetobacter baumannii is considered a troublesome cause of infection in burn units, where its capability to form biofilm and resist antibiotics significantly hampers therapeutic success. This study explored the correlations between antimicrobial resistance profiles, biofilm-producing capacity, and genetic diversity of A. baumannii strains from patients with burn wound infection in Isfahan, Iran. Ninety-six isolates were analyzed for antibiotic resistance using the disk diffusion technique and for biofilm formation through the microtiter dish assay. The prevalence of ten biofilm-related genes was investigated using specific primers. Clonal relatedness among bacterial strains was defined by Enterobacterial Repetitive Intergenic Consensus-Polymerase Chain Reaction (ERIC-PCR). A vast majority of isolates (99%) exhibited resistance to meropenem, ciprofloxacin, ceftriaxone, cefotaxime, piperacillin-tazobactam, and imipenem, qualifying them as extensively drug-resistant (XDR). Twenty-five percent of the strains were strong biofilm formers, while 68% demonstrated moderate or weak biofilm formation. The most commonly identified biofilm-related genes included bfmR (100%), ompA (100%), and bap (99%). A significant association was found between the production of biofilm, resistance to aminoglycosides, and the presence of csuE and bap genes. ERIC-PCR typing showed the presence of 3 clonal types and 7 single types, with biofilm producers predominantly clustering to clonal type 2. This work highlights a notable prevalence of biofilm-producing XDR A. baumannii in burn patients, underscoring the need for continuous surveillance and enhanced infection control strategies.