Spatial distribution of Helicobacter spp. in the gastrointestinal tract of dogs.
BACKGROUND
In dogs, the gastric Helicobacter spp. have been well studied, but there is little information regarding the other parts of the alimentary system. We sought to determine the spatial distribution of Helicobacter spp. in the gastrointestinal tract and the hepatobiliary system of dogs using culture-independent methods.


METHODS
Samples of stomach, duodenum, ileum, cecum, colon, pancreas, liver, and bile from six dogs were evaluated for Helicobacter spp. by genus, gastric, and enterohepatic Helicobacter spp. Polymerase chain reaction, 16S rRNA gene sequence analysis, immunohistochemistry, and fluorescence in situ hybridization (FISH).


RESULTS
In the stomach, Helicobacter spp. DNA was detected in all six dogs, with H. bizzozeronii and H. felis identified by specific polymerase chain reaction. Helicobacter organisms were localized within the surface mucus, the lumen of gastric glands, and inside parietal cells. The small intestine harbored gastric and enterohepatic Helicobacter spp. DNA/antigen in low amounts. In the cecum and colon, Helicobacter spp. DNA, with highest similarity to H. bilis/flexispira taxon 8, H. cinaedi, and H. canis, was detected in all six dogs. Helicobacter organisms were localized at the mucosal surface and within the crypts. Gastric Helicobacter spp. DNA was detected occasionally in the large intestine, but no gastric Helicobacter spp. were present in clone libraries or detected by FISH.


CONCLUSIONS
This study demonstrates that in addition to the stomach, the large intestine of dogs is also abundantly colonized by Helicobacter spp. Additional studies are necessary to investigate the association between enterohepatic Helicobacter spp. and presence of intestinal inflammatory or proliferative disorders in dogs.
Recordati
Camilla
C
Dipartimento di Patologia Animale, Igiene e Sanità Pubblica Veterinaria, Sezione di Anatomia Patologica Veterinaria e Patologia Aviare, Facoltà di Medicina Veterinaria, Università degli Studi di Milano, Milano, Italy. camilla.recordati@unimi.it
Gualdi
Valentina
V
Craven
Melanie
M
Sala
Lorenza
L
Luini
Mario
M
Lanzoni
Anna
A
Rishniw
Mark
M
Simpson
Kenneth W
KW
Scanziani
Eugenio
E
D000818:Animals; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D004283:Dog Diseases / Q000382:microbiology*; D004285:Dogs; D005260:Female; D041981:Gastrointestinal Tract / Q000382:microbiology*; D016998:Helicobacter / Q000235:genetics / Q000302:isolation & purification*; D016481:Helicobacter Infections / Q000382:microbiology / Q000662:veterinary*; D007150:Immunohistochemistry / Q000379:methods; D017404:In Situ Hybridization, Fluorescence / Q000379:methods; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods; D012336:RNA, Ribosomal, 16S / Q000235:genetics
D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S