Increased risk of conjunctivitis caused by oral bacteria in dogs with low craniofacial ratio

INFECTION Seoul – At the College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Korea, Sehan Shin et al. investigated the prevalence of oral bacteria in the conjunctiva of brachycephalic and non-brachycephalic dogs. Brachycephalic dogs were defined as those with a craniofacial ratio of 0.5 or less. A total of 12 brachycephalic (mean age 9.58 years) and 12 non-brachycephalic (8.33 years) dogs without systemic disease, regardless of breed and sex, were included in the study. In each group, half of the dogs suffered from periodontitis.

For the prospective study, clinical data including the craniofacial ratio, the results of ophthalmic examinations and the periodontal status of the dogs were collected. For the bacteriological examination, swabs were taken from the oral mucosa and conjunctival surfaces. Bacteria were detected and quantified using MALDI-TOF (matrix-assisted laser desorption/ionisation-time-of-flight mass spectrometry), 16S rRNA sequence analysis, and the 10-fold dilution method for cell culture analysis. Statistical analyses were performed to identify correlations and factors influencing the presence of oral bacteria in the conjunctiva.

The most common bacteria in the conjunctival flora of both groups were Micrococcus luteus, Corynebacterium spp., and Staphylococcus spp. The prevalence of oral bacteria on the conjunctival surface was 33%, with a significantly higher incidence in brachycephalic dogs (p = 0.027). Oral bacteria detected in the conjunctiva were mainly Frederiksenia canicola, Neisseria spp., and Moraxella spp. Multiple regression analysis identified age, craniofacial ratio, and gingival index as factors influencing the presence of oral bacteria in the conjunctival flora.

The authors point out in the May 2024 issue of the AMERICAN JOURNAL OF VETERINARY RESEARCH that oral bacteria were frequently isolated from severe infectious corneal ulcers. This study provides evidence that dental prophylaxis may be necessary in brachycephalic dogs to reduce the bacterial burden in the oral cavity and that the relationship between oral bacteria and ocular disease should be considered. (bs)

Authors: Shin S, Seo K, Lee GY, Yang SJ, Kim SE. Correspondence: Se Eun Kim Department of Veterinary Clinical Sciences, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Gwanak-Gu, Seoul, Korea. Email: se.kim@snu.ac.kr Study: Oral bacteria may affect conjunctival microorganisms in brachycephalic dogs: a preliminary study. Source: Am J Vet Res. 2024 Mar 4;85(5):ajvr.23.11.0260. doi: 10.2460/ajvr.23.11.0260. PMID: 38422613. Web: https://avmajournals.avma.org/view/journals/ajvr/85/5/ajvr.23.11.0260.xml