Isolation and characterization of novel Helicobacter spp. from the gastric mucosa of harp seals Phoca groenlandica

Abstract

Since the recent discovery of Helicobacter cetorum in cetaceans and its role in the development of gastritis, speculation has existed as to whether pinnipeds have Helicobacter spp. associated gastritis and peptic ulcer disease. The gastric mucosa of 4 stranded harp seals Phoca groenlandica from the Massachusetts coastline were assessed for Helicobacter spp. by culture and PCR. We cultured 2 novel Helicobacter spp. from the pyloric antrum of 1 of the 4 harp seals studied, and identified these by PCR in 2 of the 4 seals. Both gram-negative bacterial isolates were catalaseand oxidase-positive. However, a fusiform helicobacter with flexispira morphology was ureasepositive, and a spiral-shaped helicobacter was urease-negative. Slender, spiral and fusiform-shaped bacteria were detected in the gastric mucosa by the Warthin-Starry stain. Histopathologic analysis revealed mild diffuse lymphoplasmacytic gastritis within the superficial mucosa of the pyloric antrum of both infected seals. The 2 bacterial isolates were classified by 16S rRNA analysis; they clustered with other enteric helicobacters and represent 2 novel Helicobacter spp. The urease-negative bacterial isolate clustered with H. canis and the urease-positive isolate clustered with an isolate from a sea lion and isolates from sea otters. This cluster of pinniped isolates has 97% similarity to a number of Helicobacter species, but appears to be most closely related to other helicobacters with flexispira morphology. These findings suggest that the novel Helicobacter spp. may play a role in the etiopathogenesis of gastrointestinal diseases in pinnipeds. To our knowledge, this represents the first isolation and characterization of a novel Helicobacter spp. from pinnipeds. KEY WORDS: Harp seal · Pinniped · Helicobacter infection · Gastritis · Cryptosporidium Resale or republication not permitted without written consent of the publisherDis Aquat Org 57: [1][2][3][4][5][6][7][8][9] 2003 association seems to be unclear (Fox 2002, Harper et al. 2002a, Doster 2000. Recently, H. cetorum was isolated from cetaceans and thought to be involved in the development of gastritis (Harper et al. 2000(Harper et al. , 2002a.Like dogs, seals are monogastric, and gastric ulcers are usually associated with parasites and foreign bodies, although in some cases the cause of ulcers is unknown (Sweeney 1974, Bishop 1979, McClelland 1980. The distribution of harp seals ranges from the White Sea at Jan Mayen, Newfoundland, to the Gulf of St. Lawrence (Riedman 1990).The goal of this study was to determine if Helicobacter spp. could be isolated from the gastric mucosa of stranded pinnipeds. MATERIALS AND METHODS Seals.We evaluated 4 wild, stranded harp seals. All had died along the shores of New England, USA. Strandings occurred in Massachusetts in the winter of 2001, and the carcasses were collected by the New England Aquarium Marine Mammal Stranding.Sample collection. The stomach body and pyloric antrum were obtained by the submittors from 4 harp seals for culture, PCR and histop...

Discordant 16S and 23S rRNA Gene Phylogenies for the Genus Helicobacter : Implications for Phylogenetic Inference and Systematics

“…In a previous study, we demonstrated that strains with flexispira morphology fell into at least 10 Helicobacter taxa by 16S rRNA gene sequence comparison (14). Since that paper was published, Helicobacter aurati and strain MIT 01-5529A, isolated from a seal, representing two additional flexispira taxa, have been described (24,44). As noted in Fig.…”

Detection, Isolation, and Characterization of Helicobacter Species from the Gastrointestinal Tract of the Brushtail Possum

“…The S-shaped BTP isolates showed 96% similarity to Helicobacter sp. MIT 01-6242, isolated from the gastric mucosa of harp seals (Phoca groenlandica) (13). The comparison of the 16S rRNA gene sequences obtained in this study to other sequences from GenBank confirmed that the 18 isolates potentially were novel Helicobacter species.…”

Species of the Family Helicobacteraceae Detected in an Australian Sea Lion ( Neophoca cinerea ) with Chronic Gastritis

“…While any of these species may have been responsible for the development of gastritis in this animal, they also may have been mere bystanders (3), as species of Helicobacter, like those of Wolinella, may be nonpathogenic in their natural host (25,26). Indeed, with the detection of Helicobacter species in the gut of a clinically healthy sea lion (Portia) exhibiting no significant pathological features consistent with Helicobacter infections in other animals (16,17), the role of Helicobacter in this host requires further examination.…”

“…While no spiral-shaped organisms were observed in this (or the control) specimen, such Helicobacter-like organisms may not always be detected by standard staining procedures such as HE staining (4). Despite this limitation, its detection in the gut of this host, given the ability of other species to cause similar conditions of disease in other marine mammals (16,17), is novel and reflects the potential for multiple genera of the family Helicobacteraceae to infect this host. Coinfection of a host by closely related taxa has some precedence in the literature and has been reported for Campylobacter, Helicobacter, and Wolinella species (3,24).…”