An 8-month-old, 11.0-kg, sexually intact male French bulldog was presented on day 1 with a 4-month history of intermittent diarrhoea and a 7-day history of focal seizures that had been observed almost every day for 7 days. Stool consistency had been very soft to watery, and stool frequency had been > 7 times/day. Blood and mucus had been observed in the faeces. Thus, diarrhoea was considered to be induced by colitis. Four months prior to the current presentation, a faecal sample of the dog was subjected to real-time PCR analysis (IDEXX Laboratories, Inc., Tokyo, Japan) for Cryptosporidium spp., Giardia spp., Clostridium perfringens α toxin, Clostridium difficile toxin A&B, Campylobacter jejuni, Campylobacter coli, Salmonella spp., Canine parvovirus type 2, canine distemper virus and canine enteric coronavirus genes by a veterinary practitioner; a positive reaction for Campylobacter jejuni was detected in the analysis. The dog was treated with tylosin (Tylan, Eli Lilly Japan K.K., Kobe, Japan; 10 mg/kg PO, q12h) for 7 days by a veterinary practitioner; however, stool conditions did not improve. Administration of an antidiarrhoeal (Diabuster, Kyuritsu, Tokyo, Japan; 1 tablet PO, q12h) containing berberine tannate, bismuth subnitrate, geranium herb, nutgalls and scopolia extract, and an antiflatulent (Bioymbuster, Kyuritsu, Tokyo, Japan; 1 tablet PO, q12h) containing Bacillus coagulans, Bifidobacterium longuin, Lactobacillus acidophilus, Streptococcus faecalis and pancreatin, improved stool conditions. However, once these drugs were discontinued, the diarrhoea recurred.
On day 1, physical and clinical examinations, including a complete blood count (CBC), a serum biochemical analysis, radiography, an abdominal ultrasound and faecal examination, did not reveal any specific causes for chronic diarrhoea and focal seizures. A faecal sample was subjected to real-time PCR analysis (IDEXX Laboratories, Inc.) to investigate an infectious cause of diarrhoea. Meanwhile, the dog was administered erythromycin (Erythromycin, Sawai Pharmaceutical, Osaka, Japan; 10 mg/kg PO, q12h) for 14 days based on the positive result for C. jejuni infection 4 months earlier.
On day 2, real-time PCR analysis of a faecal sample collected on day 1 was found to be positive for C. difficile toxin A&B genes and negative for other pathogens. The presence of C. difficile antigen and toxin A&B proteins in a faecal sample collected on day 1 was also confirmed by an immunochromatographic test kit (Techlab C. Diff Quick Chek Complete, Alere, Chiba, Japan).
In the follow-up visit on day 16, stool conditions did not improve after administration of erythromycin in the dog. Based on the clinical and investigative findings, diarrhoea in the dog was considered to be induced by C. difficile-associated colitis. Treatment with metronidazole was proposed; however, the owner rejected this treatment because of the potential for metronidazole-induced neuropathy. To investigate the cause of focal seizures, computed tomography and magnetic resonance imaging were performed. Mild ventriculomegaly was detected in the brain of the dog on imaging, but it was unclear whether the lesion was related to the seizures. After initiating treatment with zonisamide (Consave, DS Pharma Animal Health, Osaka, Japan; 10 mg/kg PO, q12h), the seizure frequency decreased.
On day 25, the dog still had large bowel diarrhoea. Real-time PCR analysis and immunochromatography confirmed that C. difficile antigen and toxin A&B genes and proteins were still positive in a faecal sample collected on day 25. Therefore, instead of treatment with metronidazole, oral faecal microbiota transplantation (FMT) was performed after obtaining written informed consent from the owner. This treatment was approved by the Research Ethics Committee of Tokyo University of Agriculture and Technology. Fresh faeces were collected from a 9-year-old, 11.0-kg, sexually intact healthy male beagle maintained for research purposes. The healthy dog was housed in a cage and fed a commercial diet (Science Diet Adult, Hill’s-Colgate Ltd., Tokyo, Japan) once daily. Water was provided ad libitum. Physical and clinical examinations, including a CBC, a serum biochemical analysis, radiography, an abdominal ultrasound and faecal examination, did not find any abnormalities in the healthy dog, and real-time PCR analysis of a faecal sample did not detect any pathogens. Immediately after faecal collection, approximately 60 g of faeces was dissolved in 50 mL of tap water. The faecal solution was filtered through a medical gauze pad twice. A total of 30 mL of a filtered faecal solution was obtained and orally administered to the recipient dog using a syringe.
Stool consistency became normal, and stool frequency was reduced to 4–5 times/day 2–3 days after oral FMT. Faecal blood and mucus were not observed after oral FMT. Real-time PCR analysis of a faecal sample collected at 7 days after oral FMT (day 32) was negative for C. difficile toxin A&B genes. Further real-time PCR analysis of faecal samples collected on days 61 and 149 confirmed that C. difficile toxin A&B genes were still negative. The absence of C. difficile antigen and toxin A&B proteins was also verified in the faecal samples by an immunochromatographic test kit after oral FMT. In addition, diarrhoea did not recur after oral FMT and further medications were unnecessary. Stool conditions are still normal on day 190.