Investigation of Bacterial Isolations and Antimicrobial Susceptibility of Chronic Rhinitis in Cats

SIMPLE SUMMARY: Although rhinitis is a quite common disease in cats, the underlying cause is not easily explored. In addition to responding to the emerging concern regarding antimicrobial resistance and close contact between a pet and its owner, this study investigated bacterial identification and antimicrobial susceptibility in chronic rhinitis in cats. The current study found that rhinitis was more likely in younger and young adult cats, with Pseudomonas spp. being the main bacterial species, as well as multidrug-resistant, followed by Pasteurella spp., Staphylococcus spp., and E. coli. Overall, amikacin, imipenem, and meropenem, which are intravenous antimicrobial agents, exhibited high activity against most bacterial species. However, the use of antimicrobials in categories A and B (EMA) in companion animals are not recommended if other antimicrobial choices are available. Notably, this report reflects on the current antimicrobial resistance situation. Therefore, the appropriate antimicrobial usage and selected drugs should be based on antimicrobial use guidelines, the result of culture, and antimicrobial susceptibility. ABSTRACT: Chronic rhinitis is a quite common upper respiratory tract (URT) disease in cats. As a result of unclear etiology, frequently, multidrug-resistant bacteria are identified. This study investigated bacterial isolations and an antimicrobial susceptibility test (AST) in chronic rhinitis in cats. The medical records of 395 cats with chronic URT signs were reviewed at the Kasetsart University Veterinary Teaching Hospital (KUVTH) between 2016 and 2021 to survey the underlying causes of URT. Then, apart from rhinitis, other causes were excluded to identify the bacterial species and antimicrobial susceptibility. The results indicated that the most frequent finding was neoplasia, followed by rhinitis and anatomical defects. Furthermore, the only significant association was between the age range and disease group, with gender, FIV, or FeLV infection not being significant. Rhinitis was 4.7 times more likely to occur than neoplasia in younger and young adult cats in the age range < 1–3 years compared to the group > 10 years. The main bacterial species was the Pseudomonas species. Antimicrobials with a susceptibility rate of more than 90% were amikacin, gentamicin, ciprofloxacin, norfloxacin, marbofloxacin, imipenem, and meropenem. In conclusion, rhinitis was the second most common chronic URT disease in cats and was more common in younger and young adult cats. The predominant bacteria with AST in this study reflect the antimicrobial resistance situation. Thus, antimicrobial usage should follow antimicrobial use guidelines first.