Conventional diagnostic methods and immunohistochemistry in the detection of gastric Helicobacter species in dogs with chronic gastropathy

ABSTRACT An accurate diagnostic test for Helicobacter spp. infection in dogs is necessary but no gold standard diagnostic method has yet been established. The purpose of this study was to assess the sensitivity of conventional diagnostic methods as opposed to immunohistochemistry (IHC) in the detection of Helicobacter spp. in gastric samples of dogs with chronic gastropathy. Samples of gastric fundus, body and antrum were collected by gastroscopy from 13 domestic dogs presenting chronic vomit and submitted to the rapid urease test (RUT), cytopathology, histopathology with Hematoxylin-Eosin (HE) and Warthin-Starry (WS) stain, and IHC. Cohen's kappa coefficient was carried out to determine the agreement between techniques compared to IHC. Prevalence of colonization detected by IHC was 92% and was higher in the gastric fundus. The sensitivity of each technique in detecting Helicobacter spp. in the gastric fundus, body, and antrum, respectively, were as follows: RUT 50%, 70%, 17%; cytology 58%; 70%, 50%; HE 42%; 70%, 50%; WS 67%; 80%, 50%. We found that IHC was the most sensitive method for Helicobacter spp. diagnosis revealing that gastric fundus samples have higher presence of bacteria. Squash cytology enhances sensitivity and ancillary staining such as WS should be taken into consideration towards diagnosis.