The Other Helicobacters

Abstract

In the past year, a substantial number of (putative) novel Helicobacter species have been described, including Helicobacter himalayensis colonizing the Himalayan marmot and Helicobacter apodemus, colonizing the Korean striped field mouse. In addition, a putative novel gastric Helicobacter species was identified in wild gorillas and chimpanzees, for which the name "Candidatus H. homininae" was proposed. A high incidence of gastric non-H. pylori Helicobacter infection was described in China and multiple case reports have described the involvement of enterohepatic Helicobacter species, especially Helicobacter cinaedi, in a wide range of diseases. Several studies in rodent models further elucidated the mechanisms underlying the development of gastric mucosaassociated lymphoid tissue lymphoma during infection with gastric non-H. pylori Helicobacters. The effects of infection with gastric Helicobacters on the development of neuroinflammation were investigated and several enterohepatic Helicobacter species were shown to affect the composition of the gut microbiota, to influence vaccine efficiency as well as the progression of cancer in distant sites of the body. Taxonomy and PhylogenyHelicobacter himalayensis was described as a new enterohepatic Helicobacter species in 2015 [1]. H. himalayensis was isolated from gastric mucosa of Marmota himalayana in the Qinghai-Tibet Plateau in China. Analysis of the 16S rRNA gene sequence (1468 bp) showed that it was most closely related to Helicobacter marmotae (96.7% similarity), while the 23S rRNA gene sequence (2879 bp) analysis showed that it was most closely related to Helicobacter canis (96% similarity).A novel Helicobacter species was identified from the gastrointestinal tract of Korean striped field mice, for which the name Helicobacter apodemus sp. nov. was proposed [2]. The isolates were positive for urease activity and were most closely related to a reference strain of Helicobacter mesocricetorum (97.03-97.32% 16S rRNA sequence similarities).A novel Helicobacter sp. was also isolated from the cecum of the Siberian hamster [3]. Sequence analysis showed 97% sequence similarity to Helicobacter ganmani. Coinfection with Helicobacter bilis and Campylobacter spp. was observed in the Siberian hamster. Genomics and GeneticsHelicobacter suis is one of the most fastidious Helicobacter species, requiring biphasic culture conditions. Hence, cultures obtained from an individual animal may contain multiple H. suis strains. A method was developed to obtain single-colony-derived H. suis strains by culturing bacteria as colonies on 1% brucella agar plates, followed by purification and enrichment by biphasic culture [4]. However, for four of 17 strains, MLST analysis revealed genetic differences between parental and single-colony-derived strains. One colony-derived strain was further shown to have lost its capacity to colonize Mongolian gerbils.Draft genome sequences of seven enterohepatic Helicobacter species were described [5]. Six isolates (H. bilis ATCC 43879, H. canis NCTC 12...

Management ofHelicobacter pyloriinfection—the Maastricht V/Florence Consensus Report

“…Some of them have been found in humans, including H. bilis , H. cinaedi , and H. fennelliae . Besides occasional associations with gastroenteritis,365 infection with these and other enterohepatic Helicobacter species have been associated with extraintestinal diseases, including extrahepatic cholangiocarcinoma for H. bilis and H. hepaticus 366 367 and bacteraemia 368. In addition to these enterohepatic Helicobacter species, gastric non- H. pylori Helicobacter species have also been detected in humans.…”

“…Although these bacteria are often erroneously referred to as ‘ H. heilmannii ’, a number of similar but distinct zoonotically important bacterial species are in fact involved, including H. bizzozeronii , H. felis , H. heilmannii s.s. , H. salomonis , and H. suis. 367 368 373 375–379 Diagnosis of infection with one of these non- H. pylori Helicobacter species is not always straightforward, in part due to their patchy colonisation in the human stomach 373 380…”

Infection with CagA+Helicobacter pyloriinduces epithelial to mesenchymal transition in human cholangiocytes

“…The neutral or even inhibitory effect of H. bilis on H69 was mirrored by the lack of cellular proliferation by H69 cells when monitored in real-time over 72 hours days at MOI of 0, 10, 50, and 100 H. bilis ( Figure S3). Discussion Numerous species of Helicobacter have been described [65] while H. pylori was the first prokaryote confirmed to cause gastric disease, including peptic ulcer, gastric mucosa-associated tissue lymphoma, and adenocarcinoma [38,[66][67][68][69]. Bacilli of H. pylori occur in the stomach in at least half of the human population.…”

Draft Genome Sequence of Helicobacter suis Strain SNTW101, Isolated from a Japanese Patient with Nodular Gastritis

“…Helicobacter suis , naturally colonizing the stomach of pigs, is the most prevalent non- H. pylori Helicobacter species in humans with gastric diseases ( 1 – 4 ). We isolated H. suis strain SNTW101 from a urea breath test (UBT)-negative Japanese woman with nodular gastritis in 2008 ( 5 ).…”