Isolation of Oral Bacteria, Measurement of the C‐Reactive Protein, and Blood Clinical Parameters in Dogs with Oral Tumor

Abstract

Canine oral cancers have a poor prognosis and are related to chronic inflammation. This may pose a risk of secondary bacterial infection. This study aimed to compare the bacteria isolated from oral swab samples, values of C-reactive proteins (CRPs), and clinical blood profiles of dogs with and without oral mass. A total of 36 dogs were divided in three groups: no oral mass (n = 21), oral mass (n = 8), and metastasis groups (n = 7). Significantly, both the clinical groups (the oral mass group and metastasis group) showed anemia, a decrease in the albumin-to-globulin ratio (AGR), and an increase in the neutrophil-to-lymphocyte ratio (NLR), globulin-to-albumin ratio (GAR), CRP, and CRP-to-albumin ratio (CAR) compared to the normal group. CAR showed an increasing trend in the oral mass and metastasis groups (10 times and 100 times, respectively) compared to the no oral mass group ( P < 0.001 ). Neisseria spp. (20.78%) was the main isolated bacteria in all groups. The main genera in the no oral mass group were Neisseria spp. (28.26%), Pasteurella spp. (19.57%), and Staphylococcus spp. (19.57%). Neisseria spp., Staphylococcus spp., Klebsiella spp., and Escherichia spp. were found equally (12.5%) in the oral mass group. Escherichia spp. (26.67%), Pseudomonas spp. (13.33%), and Staphylococcus spp. (13.33%) were the main genera in the metastasis group. Interestingly, Neisseria spp. decreased in the clinical groups (Fisher’s exact = 6.39, P = 0.048 ), and Escherichia spp. increased in the metastasis group (Fisher’s exact = 14.00, P = 0.002 ). The difference of oral bacteria in clinical dogs compared to healthy dogs may be related to microbiome alterations, and both the clinical groups showed the increment of inflammatory biomarkers. This suggested that further studies should be conducted on the correlation between the specific bacteria, CRP, blood clinical parameters, and type of canine oral mass.

A Comparison of the Oral Microbiota in Healthy Dogs and Dogs with Oral Tumors

“…Limitations of this study include the small number of tumor patients due to the strict inclusion criteria; unfortunately, most dogs with an oral mass that were eligible for the study were treated with an antibiotic before presentation and were therefore excluded. An important limitation of our study was also the lack of inclusion of tumors of epithelial origin, making it difficult to compare our results with previous studies conducted in dogs [39], humans [22][23][24][30][31][32][33]58] or other species [35]. Additionally, the inability to control diet and home oral care in a clinical setting, and the unknown periodontal status, due to ethical concerns which prevented the use of anesthesia in healthy dogs, were further limitations.…”

“…The same applies to the use of proton pump inhibitors, which have been shown to affect the fecal microbiota of both cats [46] and dogs [47] and also has an impact on the oral microbiome of humans [48]. Consequently, all dogs in our study did not take proton pump inhibitors for at least two months prior to sampling, although this was not part of the inclusion criteria in the oral melanoma study [39]. The same applies to the intake of glucocorticoids.…”

“…decreased in both oral tumor groups. The observed differences in oral bacteria, the increase in CRP, the CRP-albumin ratio (CAR), and the neutrophillymphocyte ratio (NLR) in both oral tumor groups suggested that bacteria and oral tumors may be related, and that bacteria may play a role in carcinogenesis [39]. Nonetheless, it is important to acknowledge that carcinogenesis is a multifaceted process influenced by factors beyond the microbiome.…”