Detection of Toxin Genes and Biofilm Formation of Pseudomonas aeruginosa Associated With Respiratory Tract Infections in Riyadh, Saudi Arabia

Pseudomonas aeruginosa infections associated with the respiratory system may cause significant damage to the lung tissue, which may lead to death. This study aimed to detect the presence of toxin genes, antibiotic resistance, and biofilm formation in P. aeruginosa isolates associated with respiratory tract infections. A total of 60 P. aeruginosa strains were isolated from respiratory samples and included in the current study after confirmation using biochemical identification methods. Antimicrobial susceptibility was conducted using the MicroScan WalkAway system. Biofilm formation was assessed using the 96‐microtiter plate method. Conventional polymerase chain reaction (PCR) was used to detect the tox A and exo S genes. The results showed that 25% of P. aeruginosa isolated from respiratory tract infections were resistant to Imipenem, while most isolates were sensitive to colistin (98.3%). Among the isolates, 96.6% were biofilm producers as follows: 55% were strong biofilm producers, 18.3% were moderate biofilm producers, and 23.3% were weak biofilm producers, while 3.3% of the isolates did not produce biofilms. The tox A gene was present in 93.3% of isolates, and the exo S gene was present in 61.7%. However, our finding revealed that there is no significant correlation between the presence of toxin genes and biofilm formation as well as antibiotic resistance among the isolates. The current study assumes that each of the mentioned virulence factors may be used by P. aeruginosa during a certain stage of infection to perform a specific role. In conclusion, the presence of virulence factors such as toxin genes, biofilm formation, and antibiotic resistance in P. aeruginosa may exacerbate respiratory tract infections.