Prevalence of Clostridium difficile and Salmonella spp in juvenile dogs with parvoviral enteritis and clinically healthy controls

Abstract

Background: Clostridium difficile (CD) is the most common cause of hospital-associated diarrhoea in humans and Salmonellosis is a disease of major zoonotic importance. Canine parvovirus (CPV) is a potentially fatal cause of canine enteritis with a world-wide distribution. Persistent isolation of Salmonella spp. during routine hospital environmental surveys of the OVAH isolation ward, reserved for the treatment of CPV positive dogs, prompted investigation into a possible source. Hypothesis: Juvenile dogs affected by CPV will have a higher prevalence of faecal Clostridium difficile and Salmonella spp. compared to an apparently healthy juvenile cohort. Animals: Seventy-four client-owned dogs infected with canine parvovirus and 42 apparently healthy client-owned dogs. Methods: Prospective, longitudinal, observational study conducted at the Onderstepoort Veterinary Academic Hospital, University of Pretoria, South Africa over an 18-month period. Fresh fecal samples were collected from dogs aged 6 weeks to 9 months that were diagnosed with CPV and admitted for treatment, and from apparently healthy dogs presenting for vaccination or routine hospital procedures. CPV shedding was confirmed using negative staining electron microscopy. Clostridium difficile was diagnosed using a commercially-available faecal antigen enzyme immunoassay(EIA) for the detection of Clostridium difficile-specific glutamate dehydrogenase and for enterotoxin TcdA and cytotoxin TcdB. Faeces were submitted for the isolation, antimicrobial susceptibility testing, and serotyping of Salmonella spp. Results: The prevalence of faecal Clostridium difficile was 3% and 5% and for Salmonella spp. 22% and 31% for the CPV-cohort and apparently healthy dogs, respectively. No statistically significant associations between Salmonella status and possible risk factors or continuous variables such as age, body weight and duration of hospitalization were identified. Statistical analysis was not performed on Clostridium difficile positive dogs, due to only 2 dogs in each group testing positive. All the Salmonella spp. isolates (n = 32) were resistant to penicillin G, lincomycin and tylosin. Nine of the isolates were resistant to lincospectin and 21 showed intermediate (n = 20) or complete resistance (n = 1) to doxycycline/oxytetracycline. Salmonella spp. from nine different serotypes were identified. Conclusions and Clinical Importance: The prevalence of Clostridium difficile in the CPV and healthy juvenile dogs was similarly very low and insufficient for statistical analysis. The prevalence of Salmonella spp. in dogs infected with CPV was not statistically different from that in an apparently healthy cohort. However, the prevalence in both groups was considerably higher than that commonly reported in adult dogs and parallels previous reports in young dogs, shelter dogs, or dogs fed a raw meat diet. Of the nine Salmonella serotypes identified from 32 isolates, there were several with variable resistance to a range of antibiotics including penicillin G, lincomycin, tylosin, lincospectin, and doxycycline/oxytetracycline.