Polymerase Chain Reaction Detection of Capnocytophaga canimorsus and Capnocytophaga cynodegmi as the Emerging Zoonosis

Capnocytophaga canimorsus and C. cynodegmi, as gram-negative rods, are commensal in the oral cavities of dogs and cats and C. canimorsus can occasionally cause fatal systemic infections in humans. In addition, most human infections, caused by C. canimorsus, are associated with dog bites, licking pre-existing wounds, or the other contact with dogs. Therefore, the aim of this study was to evaluate the role of polymerase chain reaction (PCR) in detecting C. canimorsus and C. cynodegmi in oral swab samples of dogs and cats.

To this end, oral swabs were taken from 125 dogs and 35 cats enriched in the anaerobic atmosphere and then were used for DNA isolation and evaluated by PCR.

In 125 dog oral swabs, DNA of Capnocytophaga genus was prespecified in 32% of these samples (n=40). Further, 20 and 36 samples were positive for DNA of C. canimorsus and C. cynodegmi, respectively, when PCR was performed for the DNA of Capnocytophaga spp. Similarly, 23 out of 35 oral swabs of the cats were positive for the presence of the DNA of Capnocytophaga genus. Finally, all the samples were positive for the DNA of C. cynodegmi when they were analyzed by the primer specified Capnocytophaga species while only 15 samples were positive for the presence of DNA of C. canimorsus.

Overall, the risk of infection with C. canimorsus is high because of the presence of the bacteria in the mouth of cats and dogs and severe consequences of infection for humans. Therefore, the owners of cats and dogs should be informed about this risk, especially if the owners belong to specific risk groups like young children, pregnant women, elderly people, and immunocompromised patients