Association of biofilm formation with multidrug resistance in burn wound patients isolates of Pseudomonas aeruginosa in Sana’a City, Yemen

Background Burn wound infections (BWIs) represent a major cause of morbidity and mortality among hospitalized burn patients. Pseudomonas aeruginosa is recognized for its ability to acquire multidrug resistance (MDR) and form biofilms that enhance virulence and antimicrobial tolerance. Objective This study investigated the association between biofilm formation and multidrug resistance among P. aeruginosa isolates from burn wound infections in Sana’a City, Yemen. Methods A cross-sectional study was conducted at Republic Hospital, Sana’a City, Yemen, from October 2023 to December 2024. A total of 424 burn wound samples were collected and processed using standard microbiological techniques. Antimicrobial susceptibility testing was performed using the Kirby–Bauer disk diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guidelines (CLSI, 2022). Biofilm production was assessed by the microtiter plate method, and polymerase chain reaction (PCR) was used to detect biofilm-associated genes (algD, pslD, and pelF). Statistical analyses were performed using Statistical Package for the Social Sciences (SPSS) version 26.0, with p ≤ 0.05 considered significant. Results Of 424 burn wound samples, P. aeruginosa was the predominant isolate (39.6%), followed by Klebsiella pneumoniae (27.1%) and Staphylococcus aureus (19.3%). Significant risk factors associated with bacterial isolation included prior antibiotic use ( χ 2 = 16.4, p = 0.001), wound debridement ( χ 2 = 21.6, p = 0.001), and surgical skin grafting ( χ 2 = 11.7, p = 0.001). P. aeruginosa showed high resistance to ceftazidime (89.8%), cefepime (90.4%), ticarcillin (92.2%), and meropenem (61.9%), while remaining largely sensitive to colistin (97%). Among isolates, 13% were MDR, 21% extensively drug-resistant (XDR), and 51% pan-drug-resistant (PDR) strains. Biofilm formation was observed in 66.4% of P. aeruginosa isolates—19.7% strong, 47.0% moderate, and 33.3% non-producers. The biofilm-associated genes algD, pslD, and pelF were detected in 38, 35, and 27% of isolates, respectively. A significant association was observed between strong biofilm formation and the presence of the pslD gene ( χ 2 = 4.8, p = 0.03), but not with MDR status ( p > 0.05). Conclusion P. aeruginosa remains the leading cause of burn wound infections in Sana’a City, Yemen, exhibiting alarmingly high levels of carbapenem and cephalosporin resistance. Although biofilm formation was common, no significant association was found between biofilm production and multidrug resistance. The high prevalence of PDR strains underscores the urgent need for antimicrobial stewardship, routine susceptibility testing, and infection control measures in burn centers.