First detection of Helicobacter canis in chronic duodenal ulcerations from a patient with Crohn's disease.

To the Editor: A 52-year-old woman with a past history of insulin-dependent diabetes mellitus and arterial hypertension presented in February 1996 with chronic right-sided abdominal pain and diarrhea. Physical examination, blood count, renal and liver function tests were unremarkable. Colonoscopy revealed an erythematous ileum and the presence of numerous superficial ulcerations going from Bauhin’s valvula to the sigmoid colon with areas of healthy tissue between areas of diseased tissue. Colonic biopsy revealed a nonspecific colitis without granuloma and the presence of some cryptic abscesses not overcoming the muscularis mucosae layer. Ileal biopsy showed the presence of edema and hemorrhagic suffusions. Endoscopy of the upper gastrointestinal (GI) tract revealed the presence of superficial ulcerations in the descending duodenum. Biopsy showed a nonspecific inflammatory infiltrate with lymphocytes, plasmocytes, and polymorphonuclear neutrophils. A presumptive diagnosis of Crohn’s disease (CD) was made and the patient was treated with mesalazine 3 g per day, with good clinical response. In 2000 the patient interrupted her treatment and a recurrence of abdominal pain occurred. Endoscopies revealed erythematous and swollen Bauhin’s valvula and cecal mucosa as well as discrete erythema of a small portion of the descending duodenum. Ileal and cecal biopsies revealed severe erosive inflammatory modifications, as well as lesions of granulomatous cryptitis, fully evocative of CD. Duodenal biopsy showed nonspecific inflammation. Mesalazine treatment was resumed, with good clinical response. She presented again in 2002 because of epigastralgia. Colonoscopy showed only minor ileocolonic lesions and no biopsy was taken. Endoscopy of the upper GI again showed the presence of superficial ulcerations of the superior and descending duodenums. Biopsy revealed an edematous and inflammatory mucosa with marked modifications of the crypts, but no granulomatous lesions. Four biopsies of the descending duodenum were sent for microbiologic culture and Helicobacter-specific polymerase chain reaction (PCR). The biopsies were homogenized, one half of the homogenate was used for culture, the other half for PCR. Cultures were performed under aerobic, microaerophilic, and anaerobic atmospheres with horse blood agar supplemented or not with the Skirrow antibiotic mix (Oxoid, Dardilly, France). Plates were incubated for 10 days at 37 C. The Helicobacter-specific PCR assay used amplified almost the entire 16S ribosomal RNA gene (1.2 kb); the primers and conditions used were as previously described. Cultures remained negative but PCR was positive for one biopsy. The amplified fragment was sequenced and compared to deposited sequences available from the BIBI (Bio Informatic Bacteria Identification) database (http:// umr5558-sud-str1.univ-lyon1.fr/lebibi/ lebibi.cgi). Using BLAST and phylogenetic analysis, we unquestionably identified the Helicobacter detected as Helicobacter canis (99.7% nucleotide identity with the type strain of H. canis; American Type Culture Collection, Manassas, VA [ATCC] 51401, GenBank Access. No. AY631945). Since the patient was clinically stable, and since the pathogenicity of the organism was uncertain, no antibiotic therapy was administered. At the last follow-up visit in 2007 the patient was still taking mesalazine and was asymptomatic. Endoscopy again revealed small superficial ulcerations going from the cecum to the left colonic angle but the duodenum was normal. The enterohepatic helicobacters colonize the lower intestinal tract of animals and many of them have been implicated in human diseases. H. canis colonizes the colon of dogs and cats. It has been found in the feces of 1.5% of 1000 normal and diarrheic dogs without direct association with diarrheal disease. This species has been shown to possess an active toxin causing progressive distension and cell death in vitro. In vivo, a report clearly demonstrated that H. canis was responsible for a case of multifocal necrotizing hepatitis in a puppy. In humans, H. canis has been isolated from the feces of a child with gastroenteritis and also caused four cases of bacteremia. Two cases were associated with multifocal cellulitis and concerned a patient with X-linked hypogammaglobulinemia and an immunocompetent person; one was observed in a 7-month-old otherwise healthy child; the last concerned a 78-year-old man with gastric diffuse large B cell lymphoma under chemotherapy. In all cases of bacteremia, close contact with either dogs or cats was reported. Thus, H. canis in dogs and cats could constitute a potential reservoir for zoonotic transmission to humans. In our case, the patient reported having owned a cat during a 5-year period, 20 years before the onset of the disease. A marked association between the presence of enterohepatic helicobacters in digestive biopsies or in stools and inflammatory bowel diseases has been reported in only two studies, both dealing with children. In one of these works, the determination of the species involved could not be performed. In the other, helicobacters belonging to the CopyrightVC 2011 Crohn’s & Colitis Foundation of America, Inc. DOI 10.1002/ibd.21610 Published online 13 January 2011 inWiley Online Library (wileyonlinelibrary.com).