Biofilm formation on multi, extensively, and pan-drug resistance in nosocomial ESKAPE pathogens among Iraqi patients

The study investigates the prevalence of multidrug-resistant (MDR), extensively drug-resistant (XDR), and pan-drug-resistant (PDR) profiles among ESKAPE pathogens. It examines the role of biofilm formation in the development of antimicrobial resistance. This cross-sectional study, conducted between May 2024 and March 2025, analyzed 546 clinical specimens collected from patients aged 1–85 years (mean ± SD = 36.07 ± 18.97) who were admitted to intensive care, ENT, internal medicine, gynecology, surgery, and burn units across several Iraqi hospitals, including Ramadi, Al-Fallujah, Heet, Ghazi Al-Hariri, Burns Specialist, Al-Yarmouk, and Al-Hakeem. Bacterial identification was performed using the VITEK 2 Compact system, and antimicrobial susceptibility testing was performed according to CLSI (2024). Biofilm formation was assessed qualitatively using the microtiter plate method and quantitatively using sodium alginate beads. Of the 546 isolates, 331 (60.62%) were identified as ESKAPE pathogens; among these, 51.0% were MDR, 32.9% were XDR, and 9.4% were PDR. Biofilm formation was observed in 86.9% of the isolates. Notably, Staphylococcus aureus showed a significant association between MDR and strong biofilm formation (OR = 6.04, p = 0.018), whereas Klebsiella pneumoniae exhibited a weaker correlation (OR = 0.77, p = 0.015). The microtiter plate method (86.9%) demonstrated higher sensitivity than the alginate bead assay (82.4%), particularly for Enterobacter spp. (p = 0.002). The findings highlight the high prevalence of MDR, XDR, and PDR ESKAPE pathogens, particularly A. baumannii and K. pneumoniae, in Iraqi hospitals, underscoring the need to integrate antimicrobial resistance profiling and biofilm evaluation into infection control and therapeutic management.