Introduction: Biofilms are often found in communities of microorganisms in chronic and persistent infections, exhibiting high resistance against antimicrobial agents.
Biofilm serves as a barrier, impeding the penetration of drugs and constraining their effectiveness. Multiple methods, such as the Tissue Culture Plate method, Congo Red Agar method, Tube method, bioluminescent assay, and fluorescent microscopic examination, can be used to evaluate biofilm production. Methods: The study included a total of ۳۰۰ clinical isolates representing a range of bacterial species, including Acinetobacter baumannii (n=۹), Coagulase Negative Staphylococcus (n=۷), Enterobacter aerogenes (n=۷), Enterococcus faecalis (n=۱۵), Escherichia coli (n=۱۳۷), Klebsiella pneumoniae (n=۲۳), Proteus mirabilis (n=۴), Pseudomonas aeruginosa (n=۱۶), Salmonella typhi (n=۱۱), and Staphylococcus aureus (n=۶۸). Associations among isolates capable and incapable of biofilm formation and their multidrug resistance phenotypes were evaluated. Results: Among the ۳۰۰ clinical isolates tested, ۲۸۹ isolates (۹۶.۳%) exhibited biofilm formation. The most prevalent biofilm-forming organisms were A. baumannii (n=۹), Citrobacter koseri (n=۱), Coagulase Negative Staphylococcus (CONS) (n=۷), E. aerogenes (n=۷), E. faecalis (n=۱۵), E. coli (n=۱۳۷), Klebsiella oxytoca (n=۱), K. pneumoniae (n=۲۳), P. mirabilis (n=۴), P. aeruginosa (n=۱۶), S. typhi (n=۱۱), S. aureus (n=۶۸), and Streptococcus pneumoniae (n=۱). The biofilm-forming isolates demonstrated increased resistance compared to isolates that did not form biofilms. Conclusion: Antimicrobial resistance represents a critical characteristic of infections involving biofilms. The study identified biofilm production in ۹۲.۷% of the isolates tested via TCP and in ۷۲.۳% of the isolates using the CRA. Furthermore, it was observed that pathogens with multidrug resistance (MDR) exhibited a higher biofilm production tendency than non-producing pathogens.