A case control study of Salmonella SPP. infection in stray dogs in Tehran shelters and the correlation between paraclinical tests results and clinical findings

Salmonellosis as a zoonotic disease in dogs is not fully understood, and various reports have pointed to the transmission of antibiotic-resistant salmonella from dogs to humans. The current study aimed to evaluate the serologic and bacteriologic prevalence of Salmonella spp. in stray dogs placed in animal shelters around Tehran, compare the results to those of asymptomatic dogs, and determine the serotype of isolated species, as well as their antibiotic susceptibility pattern. A total of 100 fecal swab and blood samples were obtained from symptomatic and apparently healthy dogs (clinically) placed in four animal shelters around Tehran, Iran. Fecal and blood culture, as well as dog food culture, tube agglutination test, serotyping, and antibiotic susceptibility testing were performed on the samples. Fever, lethargy, diarrhea, and abdominal pain were observed in all the dogs in the case group, and bloody diarrhea was the least commonly detected symptom in clinical examination. A number of 11 and 4 collected fecal swabs from the case and control groups were positive for Salmonella spp., respectively. The polymerase chain reaction (PCR) also confirmed the laboratory tests results. Blood culture on the selective medium was negative for all the cases. Moreover, 60% and 100% of dogs in the case and control groups showed inflammatory markers in their blood test. The tube agglutination test was positive for 12% of the samples from the case group, while it was positive only for 5% of cases in the control group. The highest and lowest antibiotic resistance was observed against gentamicin and ciprofloxacin from the case group, respectively. Salmonella spp. infection in stray dogs placed in animal shelters is a great public health concern. In this regard, it is recommended that these animals be regularly monitored since they serve as Salmonella carriers.