Identification of canine saliva using mRNA-based assay.

A dog saliva analysis in addition to a bite-mark analysis may be important for evidence when a crime involves a dog bite. In this study, the utility of detecting canine saliva-specific mRNAs to identify canine saliva was evaluated. Canine saliva swabs (n = 20), urine swabs (n = 20), body surface swabs (n = 20), whole blood samples (n = 10), human saliva (n = 20), human skin surface swabs (n = 20), and human whole blood (n = 20) were tested. The saliva-specific genes encoding statherin (STATH), carbonic anhydrase VI (CA-VI), and dog allergens (Canf1 and Canf2) were analyzed as candidate genes. Moreover, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as confirmation of canine mRNA extraction. STATH, CA-VI, Canf1, Canf2, and GAPDH mRNAs were detected in 19/20, 1/20, 11/20, 4/20, and 20/20 saliva samples, respectively. The STATH, CA-VI, Canf1, Canf2, and GAPDH mRNAs did not exhibit cross-reactivity with samples of human origin. This mRNA-based assay was also able to detect canine saliva in mock forensic samples. The results of this study indicated that the detection of STATH mRNA is useful for the identification of canine saliva, and GAPDH is a suitable marker for canine mRNA extraction.

Oral bacterial DNA-based discrimination of human and canine saliva for the analysis of indistinct bite marks.

Analyzing ambiguous bite marks using conventional morphological approaches to identify attackers is difficult; thus, applying molecular biological methods for identifying an attacker from their saliva is a possible approach in a forensic investigation. This study aimed to establish oral bacterial DNA-based human and canine saliva markers and develop a practical method for their discrimination. We considered Streptococcus oralis and Pasteurella canis as human and canine saliva marker candidates, respectively. Duplex bacterial DNA detection using melting curve analysis was designed and evaluated for forensic applicability using proof-of-concept experiments. S. oralis DNA was detected from human saliva samples from 30 out of 30 individuals, and P. canis DNA was detected from canine saliva samples from 73 out of 77 individuals (26 dog breeds). Additionally, both bacterial DNA markers were accurately detected from human blood-contaminated saliva samples and mock indistinct bite marks. Our results indicate that both bacterial DNA markers were sensitive, robust, and discriminating saliva markers. We consider that our duplex bacterial DNA examination is a simple, practical, and useful method for the detection of saliva from indistinct bite marks and discrimination between human and canine saliva.

Polyphasic Validation of a Nisin-Biogel to Control Canine Periodontal Disease.

BACKGROUND: Periodontal disease (PD) is a highly prevalent inflammatory disease in dogs. This disease is initiated by a polymicrobial biofilm on the teeth surface, whose control includes its prevention and removal. Recently, it was shown that nisin displays antimicrobial activity against canine PD-related bacteria. Moreover, guar gum biogel has shown to be a promising topical delivery system for nisin. METHODS: In this study we aimed to evaluate the antimicrobial activity of the nisin-biogel in the presence of canine saliva and after a 24-month storage, at different conditions, using a canine oral enterococci collection. We also studied the nisin-biogel cytotoxicity using a Vero cell line and canine primary intestinal fibroblasts. RESULTS: The presence of saliva hampers nisin-biogel antimicrobial activity, and higher nisin concentrations were required for an effective activity. A significant reduction (p ≤ 0.05) in inhibitory activity was observed for nisin-biogel solutions stored at 37 °C, over a 24-month period, which was not observed with the other conditions. The nisin-biogel showed no cytotoxicity against the cells tested at concentrations up to 200 µg/mL. CONCLUSIONS: Our results confirmed the potential of the nisin-biogel for canine PD control, supporting the development of an in vivo clinical trial.