Fecal Polymerase Chain Reaction with 16S Ribosomal RNA Primers Can Detect the Presence of GastrointestinalHelicobacterin Dogs

Abstract

Questions about pathogenesis and therapy forHelicobacterinfections in dogs could be answered with a simple, noninvasive, sensitive, and specific diagnostic test. We hypothesized that a fecal polymerase chain reaction (PCR) assay would detectHelicobacterand could be useful for assessing therapeutic responses. Paired gastric biopsies and fecal samples were obtained from 39 random source dogs (group I). Gastric biopsies from each of these dogs had histologic evidence of gastric spiral bacteria, and paired gastric tissue and fecal samples produced a 375‐base pair (bp) product when amplified by PCR withHelicobacter‐specificprimers. Specificity of the PCR product was confirmed by detection of expected 60‐, 119‐, and 196‐bp products followingHinfl digestion. Direct sequencing of amplicons from paired PCR products from gastric biopsy and fecal samples from 8 group I dogs showed that gastric products had the highest homologies with known gastricHelicobacterspecies, whereas fecal products had the highest homologies with intestinal species. Healthy mixed‐breed dogs (group II; n = 8) with histologically confirmed spiral bacteria infection were treated with a 21‐day course of metronidazole, amoxicillin, and famotidine. Fecal samples were collected from group II dogs twice before and within 3 days of completion of treatment. The PCR results correctly identified 15/16 pretreatment samples as positive; 1 pretreatment sample was negative. PCR results identified 8/8 posttreatment samples asHelicobacternegative. Fecal PCR is a useful test for detectingHelicobacterinfection in dogs. This assay may be useful as a screening test for infection and could be used to address questions relevant to pathogenesis and therapy.