Pseudomonas aeruginosa: A Current update on biofilm formation, immune response and antibiotic resistance

Pseudomonas aeruginosa is a Gram-negative bacillus found ubiquitously in nature and is known to cause life-threatening infections. A prime example of an opportunistic pathogen, P. aeruginosa is responsible for infections in environmental, industrial, and hospital settings. It has been classified as one of the “superbugs” involved in nosocomial infections and is a member of the ESKAPE pathogen group. Its virulent nature makes it a potent causative organism in both device-associated infections (such as catheter-associated bloodstream and urinary tract infections) and non-device-related infections (such as cystic fibrosis, otitis media, keratitis, and ventilator-associated pneumonia). Despite the use of various antimicrobial agents against P. aeruginosa, complications from hospital-acquired infections persist. Multiple studies have demonstrated, P. aeruginosa readily forms biofilms during prolonged infections, making treatment more challenging. This can be attributed to the fact that antibiotics are less effective against microbial biofilms. P. aeruginosa possesses several virulence factors, including lipopolysaccharides, extracellular polysaccharides (EPS), and toxin secretion systems such as the type III secretion system (T3SS), which evade host immunity and compete with other bacteria. The synergistic effect of these factors, along with biofilm formation, protects the pathogen from host immune defenses and reduces the efficacy of antimicrobial agents. This review provides a conceptual framework for understanding the association between microbial biofilms and host immune responses. Additionally, it emphasizes the critical need to address P. aeruginosa biofilms to improve patient outcomes and reduce hospital-acquired infections.Keywords: Biofilm; Immune response; Host interaction; Pseudomonas aeruginosa; Device-related biofilm