Comparison of bacterial culture results obtained from three different sampling locations in dogs and cats with chronic nasal disease.

Aims: To assess agreement of bacterial culture results from samples taken from nasal discharge, the nasal cavity and nasal biopsy from dogs and cats with nasal disease.

Methods: Nineteen dogs and 21 cats with different nasal diseases (chronic rhinitis, n = 30; neoplasia, n = 7; sinonasal aspergillosis, n = 3) were prospectively enrolled in the study. Nasal swabs were taken bilaterally from nasal discharge at the nares, the nasal cavity, and one nasal mucosal biopsy per side. All samples were subjected to aerobic bacterial culture. Kappa statistics were used to evaluate agreement for the most prevalent bacterial species between sampling sites.

Results: A positive culture result for at least one bacterial species was detected in 80% of samples from nasal discharge/nares, 92% of nasal cavity samples, and 75% of biopsy samples. The mean agreement between the three sampling sites for positive vs. negative culture results was never greater than moderate and the precision of the estimates of agreement varied widely.The most frequently isolated bacterial species in dogs were Staphylococcus pseudintermedius, Staphylococcus spp. and Streptococcus spp. In cats, Pasteurella spp. and Staphylococcus felis were the bacterial species cultured most frequently.For the most prevalent cultured species, Staphylococcus spp., mean agreement between sites was never greater than fair and the precision again varied widely.

Conclusion: This study indicates that bacterial culture results in feline and canine nasal disease are site-specific and there was no evidence from this study for consistency between sites within a patient for many bacterial species. Consequently, if bacterial culture results from nasal swabs are used to guide therapeutic antimicrobial choice, different treatments may be selected depending on the site of culture. As a consequence, there is no evidence from this study that nasal bacterial cultures should be recommended as a routine diagnostic measure.