Abstract
Background: Pseudomonas aeruginosa is an important opportunistic pathogen resulting in treatment-resistant subclinical mastitis in dairy cows. Examination of the frequency of some important virulence genes in isolates from bovine mastitis can be necessary for better management and recognition of infections caused by this bacterium. Objectives: This study was conducted on the frequency of some important exotoxin genes in P. aeruginosa samples derived from bovine mastitis in the city of Tabriz in 2022. Methods: This study was performed with 120 bacterial samples of P. aeruginosa that were isolated from clinical samples of bovine mastitis and were considered to investigate the frequency of some important exotoxin genes. Bacterial DNA was extracted, and the presence of exotoxin A, T, and U genes in P. aeruginosa samples was found by PCR method. Results: The frequency of exotoxin A, T, and U genes in P. aeruginosa samples was 18 (15%), 32 (26.6%), and 26 (21.6%), respectively, and 8 (6.6%) P. aeruginosa samples possessed all 3 intended genes simultaneously; while 76 (63.3%) P. aeruginosa samples lacked the tested genes. Conclusions: A relatively high frequency of exotoxin genes studied can be a serious warning to treat and control the bovine mastitis caused by this bacterium.