Helicobacter Species other than Helicobacter pylori: Emerging Pathogens in Humans and Animals

Abstract

Many novel Helicobacter species are now known to play a role in naturally occurring gastrointestinal diseases in humans and several species of animals. This chapter provides an overview of the enterohepatic and gastric helicobacters (other than H. pylori) and their emerging role as important gastrointestinal pathogens with zoonotic potential. Enterohepatic helicobacters such as H. cinaedi, H. fennellwe and H. westmeadii have been discussed in the chapter. H. cinaedi, previously classified as C. cinaedi(CLO-IA), was first isolated from the lower bowel of homosexual men with proctitis and colitis. In a retrospective study of 23 patients with H. cinaedi-associated illness, 22 had the organism isolated from blood using an automated blood culture system where a slightly elevated growth index was noted. This study also described a new H. cinaedi-associated syndrome, consisting of bacteremia and fever accompanied by leukocytosis and thrombocytopenia. Non-H. pylori gastric helicobacters including H. heilmannii and H. felis are discussed. The various Helicobacter spp. and their associated diseases in numerous hosts allow us the means to assess pathogenic mechanisms, as well as the utility of these in vivo models to develop various therapeutic and prophylactic strategies to eradicate or prevent Helicobacter-induced gastrointestinal disease in humans. The ultimate goal of these studies will be to eliminate afflictions causing significant human morbidity and mortality in both the developed and the developing worlds.