Biofilm Formation and its Association with Gram Negative Sepsis Pathogenicity

Background and objectives: Biofilm formation is an important virulence factor that protects an organism from antimicrobial agents as well as host immune effectors, thus allowing organisms to invade, survive, and cause persistent-reoccurring infection in host cells. The aim of this study was to investigate the ability of sepsis-causing gram-negative bacteria to form biofilms, evaluate the association between antibiotic resistance pattern and biofilm formation, determine the role and influence of biofilm formation on pathogenicity and clinical outcome of sepsis. Methods: A prospective study conducted from October 2020 to August 2021, non-replicated gram-negative bacteria isolates were recovered from blood samples of patients with suspected bacteremia, sepsis, and sepsis shock and identified using biochemical procedures. Antimicrobial susceptibility patterns of GNB isolates were determined using the Kirby-Bauer disc diffusion method and interpreted using CLSI guidelines. The ability of GNB isolates to form biofilm was assessed using Congo red agar and the tissue culture plate method. Results: Of the 160 Gram-negative bacteria tested, biofilm formation was seen in 73 (45.63%) isolates. Isolates are Klebsiella pneumoniae (39.73%), Acinetobacter spp. (34.25%), Escherichia coli (23.29%), Pseudomonas aeruginosa (1.37%), and other non-fermenters (1.37%). Isolates were highly resistant to cephalosporins, fluoroquinolones, and the penicillin group of antibiotics. No statistical relationship was found between resistance pattern, clinical outcome, and biofilm formation. Conclusion: In the current study, we found that 45.63% of gram-negative bacteria causing sepsis were biofilm producers. Klebsiella pneumonia isolates exhibited the highest levels of biofilm formation and antimicrobial resistance. Based on the strength of biofilm formation, most isolates were weak biofilm producers, and there was no statistical correlation between the formation of biofilms and antimicrobial resistance, indicating that the formation of biofilms was not a determining factor for resistance.