Table 58-6.
Bacterial Causes of Large Intestinal Disease in Dogs, Prevalence of Isolation From Feces of Normal Animals, Clinical Signs of Symptomatic Infection, and Diagnostic Approaches to Infection and Their Efficacy for Determining Disease Causation
| Bacterial Agent | Prevalence in Normal Dogs | Clinical Signs | Diagnostic Tests | Utility for Diagnosis of Disease Causation |
|---|---|---|---|---|
| Brachyspira pilosicoli | 6% to 66% | Watery, mucoid, or mucohemorrhagic large bowel diarrhea | Fecal culture in selective media and multilocus enzyme electrophoresis for identification of B. pilosicoli | Disease causation of B. pilosicoli unclear |
| Polymerase chain reaction (PCR) identification of B. pilosicoli 16S rRNA in feces | ||||
| Campylobacter jejuni | ≤90% | Watery, mucoid to bloody diarrhea | Characteristic darting motility observed in fecal wet mounts | None |
| Fecal culture in selective media for Campylobacter | ||||
| PCR-restriction fragment length polymorphism demonstration of Campylobacter genes in feces | ||||
| Clostridium perfringens | ≥80% | Acute, nosocomial large bowel diarrhea | Fecal culture for C. perfringens | None |
| Fecal cytology ≥3 endospores per high-power field | Poor | |||
| PCR identification of cpe gene | Fair to good (in combination) |
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| Immunodetection of C. perfringens enterotoxin (CPE) in feces | ||||
| Clostridium difficile | ≤40% | Mixed small and large bowel diarrhea ± acute hemorrhagic gastroenteritis | Fecal culture for C. difficile | None |
| PCR identification of toxin A or B genes | None | |||
| Immunodetection of toxin A ± toxin B in feces | Fair | |||
| Immunodetection of toxin A ± toxin B in culture isolate of C. difficile | Good | |||
| Enteropathogenic Escherichia coli (EPEC) |
≤7% | Acute-to-chronic, watery, sometimes hemorrhagic, diarrhea | Demonstration of attaching and effacing intestinal lesions by electron microscopy or immunofluorescence and absence of Shiga-like toxins | Good |
| Demonstration of locus of enterocyte effacement (LEE)-associated genes (e.g., eae) in fecal extracts or bacterial cultures by PCR or DNA hybridization | Fair | |||
| Enterotoxigenic Escherichia coli (ETEC) |
<3% | Nonbloody, watery, small bowel diarrhea | Demonstration of enterotoxin in fecal extracts or bacterial cultures by (a) Y-1 cell cytotoxicity assay or (b) enzyme-linked immunosorbent assay (ELISA) | Good (in combination) |
| Demonstration of enterotoxin genes in fecal cultures by PCR and Southern blot hybridization | ||||
| Enterohemorrhagic Escherichia coli (EHEC) | ≤5% (25% Greyhounds) |
Watery or mucoid to hemorrhagic diarrhea | Demonstration of Shiga-like toxin in fecal extracts or bacterial cultures by (a) Vero cell cytotoxicity assay or (b) ELISA | Good (in combination) |
| Demonstration of Shiga-like toxin encoding genes in fecal extracts or bacterial cultures by (a) PCR or (b) in-situ hybridization | ||||
| Salmonella | 1% to 36% | Watery or mucoid to hemorrhagic diarrhea | Culture or PCR identification of Salmonella in feces | Poor |
| Culture or PCR identification of Salmonella in sterile body fluids | Good |