Antibiotic resistance profiles of Pseudomonas aeruginosa isolates containing virulence genes

A most common opportunistic pathogen, Pseudomonas aeruginosa is present in both humans and animals and responsible for various nosocomial infections and healthcare settings related infections. Different virulence genes like; oprL (membrane lipoprotein L) and toxA (exotoxin A i.e. ETA) in P. aeruginosa, assist in its pathogenicity, toxicity and contribute to high antibiotic resistance. So considering the risk of zoonotic transmission of P. aeruginosa through animal-related foods, this study aimed to monitor the prevalence of oprL and toxA virulence genes and antimicrobial resistance in P. aeruginosa isolates, obtained from animal (Cow’s milk) and human clinical samples.

Of the total 120 collected samples for this study, every 60 samples were collected from animals and humans from respective laboratories. Total 76 isolates of P. aeruginosa were isolated and identified by morphological and biochemical tests. The presence of virulence factors like oprL and toxA were evaluated by PCR analysis and antimicrobial resistance was assessed by antibiotic susceptibility test (Kirby-Bauer method).  

From the total 76, P. aeruginosa isolates obtained from both animal and human isolates, alone presence and coexistence of both toxA and oprL genes in P. aeruginosa isolates; were detected in PCR analysis. PCR analysis results showed in P. aeruginosa isolates, alone distribution of toxA and oprL genes is, 75% and 54.16% in animals, and 84.61% and 80.76% in humans, respectively. The coexistence of both genes was 37.50% and 40.32% in animals and human isolates, along with high antibiotic resistance in most P. aeruginosa isolates.  

Therefore, this study suggested PCR analysis can be used for fast and specific detection of oprL and toxA genes in P. aeruginosa. Monitoring of these genes can help to prevent the risk of transmission of multi-drug resistant P. aeruginosa, from animals to humans.