Increased expression of genes involved in biofilm formation in a multidrug-resistant environmental Pseudomonas aeruginosa isolate

Abstract

Introduction: Pseudomonas aeruginosa is an important opportunistic pathogen associated with majority of the hospital-acquired infections in immunocompromised patients, worldwide. Biofilms formed by this bacterium increase its resistance toward antibiotics, which in turn increase morbidity and mortality. As environmental isolates of P. aeruginosa are also capable of producing virulence-associated traits, they can be considered as potential pathogens. Materials and Methods: This study was undertaken to compare the expression of some of the biofilm genes such as algD, pslA, pslB, pelA, and pelD in environmental and clinical isolates of P. aeruginosa isolated from Coastal Karnataka. The expression of biofilm-forming genes in strong biofilm-forming P. aeruginosa isolated from sputum (HS26), wound swab (HW20), and environment (EN4) were quantified at different time points of incubation (18, 25, 48, and 72 h). In addition, the sensitivity of the selected isolates to commonly used antibiotics (amikacin, aztreonam, carbenicillin, ciprofloxacin, cefotaxime, imipenem, and gentamicin) was investigated. Results: The current investigation revealed the presence of a multidrug-resistant environmental isolate with higher expression of the biofilm genes as compared to the clinical ones. In the environmental isolate, the relative expression of pslA, pslB, pelD, and pelA gene was increased by 11, 10, 10, and 9 folds, respectively, at 48 h. Conclusion: The study suggests the possibility of such multidrug-resistant biofilm-forming environmental isolates of P. aeruginosa getting transferred to the hospital setting and causing life-threatening biofilm-associated infections.