Salmonella Infection, Isolation and Antimicrobial Resistance in Diarrhoeic Dogs Presenting to Clinics in Northwestern Nigeria

Salmonella is one of the most common food-borne bacteria incriminated in gastroenteritis in dogs. The emergence of multidrug resistance (MDR) genes raises spectre of intractable disease and constitute significant public health risk. Already, there are various reports of resistance to several antimicrobials by Salmonella isolates from canine patients. This study was therefore conceived to investigate for the first time in the studied region, Salmonella isolates circulating in canine population in Sokoto State, northwestern Nigeria. Presenting canine out-patients and those admitted for emergencies with overt clinical signs for salmonellosis were recruited for the study. Salmonella was isolated from blood and faecal samples using standard laboratory techniques as required by the Clinical and Laboratory Standards Institute (CLSI). The Gram stain, Salmonella-Shigella agar (SS agar), Brilliant Green Salmonella agar (BGSA) and finally the xylose lysine deoxycholate agar (XLD) at specified temperatures and carbon dioxide adjustments were all applied on samples to isolate Salmonella as pure culture. The Kirby Bauer Disk diffusion method was used to test for antimicrobial resistance. Overall, a prevalence of 19.7% was recorded with pyrexia (18.5%) and diarrhea (13.7%) showing statistically significant (P<0.05) non-random association with Salmonella isolation in patients. The puppy age groups (from day one to five months) recorded prevalence of 31(21.2%) followed by middle-age dogs (6-months to a year) recording prevalence of 24(22.2%). Male dogs presented preponderance of cases compared to the females with prevalence of 48(76.1%). The Nigerian local dog was the highest in the number of cases with a statistically significant (P<0.05) prevalence of 23(36.5%), the German shepherd recorded isolation rate of 19(30.2%) that was also statistically significant (P<0.05). Various antimicrobials used recorded varying degree of resistance patterns when tested with isolates. A total of 19 isolates accounting for 43.2% were resistant to tetracycline, 15(35.7%) isolates recorded resistance for ceftriaxone, 13 isolates accounting for 38.2% presented resistance for metronidazole and 11(27.5%) recorded resistance for amoxicillin. Conversely, isolates were 100% susceptible to chloramphenicol and cotrimoxazole. It is imperative for small animal clinicians, diagnosticians, researchers and public health policy makers to have credible time-tested data on resistance status of Salmonella isolates in dogs, as this is a roadmap to a healthy canine and human population.