New <i>Helicobacter</i> Species in Humans

<jats:p>During the last decade several new Helicobacter species have been isolated from human gastric mucosa, fecal samples, liver, and gallbladder. Gastric corkscrew-shaped Helicobacter species: H. heilmannii is usually seen in the gastric foveolae in 0.2–0.6% of histological sections from the gastric mucosa of patients with dyspepsia in Western Europe, but it has only been cultured once. It is genetically and morphologically closely related to H. bizzozeronii and H. salmonis which are common in dogs and cats. It causes constantly active chronic gastritis and is regularly associated with peptic ulcer. Intestinal Helicobacter species: H. cinaedi, H. fennelliae, H. pullorum, H. westmeadii, H. canadensis, and ‘H. rappini’ have been isolated from patients with enteritis and proctitis. H. fennelliae, H. cinaedi, H. westmeadii, and ‘H. rappini’ have been isolated also from patients with septicemia. Studies indicate that H. cinaedi is transmitted from hamsters and that H. pullorum is common in chickens. ‘H. rappini’ has been isolated from sheep, dogs, and mice, whereas no animal reservoir has been found for H. fennelliae. Except for the cases of septicemia, none of these Helicobacter species have yet been proven to cause human disease, but they are suspected to play a role in inflammatory bowel diseases. Hepatobiliary Helicobacter species include several Helicobacter species isolated from bile and liver of animals, but only H. bilis has been isolated from the human gallbladder and H. pylori from the human liver. H. bilis has been isolated from dogs, cats, mice, and rats. Nonpylori Helicobacter species are usually difficult to culture and may be more frequently causes of human disease than realized today.</jats:p>