Antibiotic susceptibility of epizootic strains of Pseudomonas aeruginosa isolated from various animal species of the Dnipropetrovsk region

Pseudomonas aeruginosa is an opportunistic bacterium commonly found in the environment that causes life-threatening infections in livestock, poultry, fish, and humans. Infection with this microorganism is dangerous due to its natural and acquired resistance to antimicrobial agents. Our study focused on conducting laboratory analysis of biological material (parenchymal organs, conjunctival sac fluid, and wound pus) collected from animals with various pathological conditions, identifying the isolated strains, and determining their antibiotic sensitivity. The isolates were identified using standard methods employed in microbiological practice. The cultural and biochemical properties of the pure cultures were assessed on both non-selective and selective growth medium. Antibiotic sensitivity was determined using the disk diffusion method on Mueller-Hinton agar. As a result of the study, the isolates were identified as P. aeruginosa. They were gram-negative, short to medium-sized rods. The isolates exhibited well-expressed proteolytic activity, weak saccharolytic properties, and were oxidase- and catalase-positive. It was established that fluoroquinolones (norfloxacin and ciprofloxacin) were effective against 80% of P. aeruginosa strains, and two aminoglycosides were effective in 60% (kanamycin) and 40% (gentamicin) of cases. Only one epizootic strain, isolated from wound pus in a laboratory animal, was sensitive to polymyxin (20%). Two isolates, obtained from the parenchymal organs of chicks and lambs kept in private households, were sensitive to only one (norfloxacin) or three (kanamycin, norfloxacin, and ciprofloxacin) antibiotics tested in vitro. All epizootic strains of P. aeruginosa demonstrated 100% resistance to amikacin and tetracycline. Regular monitoring of P. aeruginosa isolates' resistance to antibacterial agents will help reduce the spread of antibiotic-resistant strains.