Antimicrobial sensitivity of bacterial isolates and molecular detection of Staphylococcus aureus and Staphylococcus pseudintermedius isolated from urinary tract infections of canines

Urinary tract infections (UTIs) are commonly encountered in canine clinical cases and can result in significant health complications if not properly treated. This study isolated and identified bacterial pathogens from dogs with clinical signs of UTI. Antimicrobial susceptibility profiling was performed on the bacterial isolates and further molecular detection of Staphylococcus aureus and Staphylococcus pseudintermedius was also performed. A total of 104 urine samples were collected via cystocentesis and catheterization. Bacterial identification was conducted using standard bacteriological procedures, and antimicrobial susceptibility was assessed using the disc diffusion method with 21 different antimicrobial discs. Polymerase chain reaction (PCR) was used for molecular detection of S. aureus and S. pseudintermedius using resistance genes mecA, tetK, and tetM. Of the 104 samples, 91 (87.50%) yielded pure bacterial cultures, 3 (2.88%) had mixed growth, and 10 (9.61%) had no growth. Among the 91 isolates, 58 (62.63%) were Gram negative and 33 (36.26%) were Gram positive. PCR identified 10 isolates as S. aureus and 12 as S. pseudintermedius. Antimicrobial susceptibility testing showed the highest sensitivity to enrofloxacin and ciprofloxacin (67.03%), followed by amoxicillin–clavulanic acid (58.24%), chloramphenicol (57.14%), nitrofurantoin (56.04%), gentamicin (54.94%), and amikacin (51.64%). mecA was detected in 7 S. aureus and 7 S. pseudintermedius isolates, tetK in 3 isolates each, and tetM in 2 S. aureus and 4 S. pseudintermedius isolates. These findings underscore the prevalence of antimicrobial-resistant pathogens in canine UTIs and highlight the need for routine diagnostic testing to guide effective and targeted antimicrobial therapy.