Review: Other Helicobacter species

Abstract

This article is a review of the most important, accessible, and relevant literature published between April 2018 and April 2019 in the field of Helicobacter species other than Helicobacter pylori. The initial part of the review covers new insights regarding the presence of gastric and enterohepatic non‐H. pylori Helicobacter species (NHPH) in humans and animals, while the subsequent section focuses on the progress in our understanding of the pathogenicity and evolution of these species. Over the last year, relatively few cases of gastric NHPH infections in humans were published, with most NHPH infections being attributed to enterohepatic Helicobacters. A novel species, designated “Helicobacter caesarodunensis,” was isolated from the blood of a febrile patient and numerous cases of human Helicobacter cinaedi infections underlined this species as a true emerging pathogen. With regard to NHPH in animals, canine/feline gastric NHPH cause little or no harm in their natural host; however they can become opportunistic when translocated to the hepatobiliary tract. The role of enterohepatic Helicobacter species in colorectal tumors in pets has also been highlighted. Several studies in rodent models have further elucidated the mechanisms underlying the development of NHPH‐related disease, and the extra‐gastric effects of a Helicobacter suis infection on brain homeostasis was also studied. Comparative genomics facilitated a breakthrough in the evolutionary history of Helicobacter in general and NHPH in particular. Investigation of the genome of Helicobacter apodemus revealed particular traits with regard to its virulence factors. A range of compounds including mulberries, dietary fiber, ginseng, and avian eggs which target the gut microbiota have also been shown to affect Helicobacter growth, with a potential therapeutic utilization and increase in survival.

A novel role for the pineal gland: Regulating seasonal shifts in the gut microbiota of Siberian hamsters

“…114,115 Although some phyla 116,117 and genera 118,119 have been correlated with specific physiological responses, it is important to note that bacterial species function can vary within the same genus. [120][121][122][123][124] This makes it challenging to form conclusions about the roles of genera as a whole within the microbiota, as well as to reduce the function of the entire microbiota as a system-which contains trillions of microorganisms 32 -and characterize it by only a handful of community members. 116,125 These points should be carefully considered when analyzing the microbiota and its many potential effects on behavior and physiology.…”

Helicobacter cinaedi bacteremia in a returning traveler

“…This case further illustrates the importance of H. cinaedi as an emerging pathogen in immunocompetent patients, with a wide variety of possible clinical presentations [ 1 , 2 ]. As a slow-growing fastidious organism, H. cinaedi is difficult to isolate from culture [ 1 ].…”

“…Species belonging to the enterohepatic group inhabit the gastrointestinal and hepatobiliary systems of various mammal and bird hosts [ 3 ]. One of the most studied enterohepatic Helicobacter species is Helicobacter cinaedi , which is being increasingly demonstrated as a cause of human infection [ 2 ]. H. cinaedi was first isolated from rectal swabs from MSM with gastroenteritis, proctocolitis and proctitis in 1984 [ 1 ].…”

“…At this time it was designated as Campylobacter -like organism type-1 (CLO-1), and was later re-classified as H. cinaedi in 1991 [ 1 ]. Since this time human infection with H. cinaedi has been increasingly documented in other patient groups, including both immunocompromised and immunocompetent hosts, with a variety of clinical presentations and syndromes [ 1 , 2 ]. Bacteremia is one of the most common manifestations of H. cinaedi infection, and is thought to be due to bacterial translocation from the intestinal tract to the vascular system [ 1 , 4 ].…”

“…The genus Helicobacter comprises 39 species, with Helicobacter pylori the most well-known pathogenic Helicobacter species in man [ 1 ]. Of the non‐ Helicobacter pylori Helicobacter (NHPH) species, Helicobacter cinaedi is an emerging cause of infection in humans [ 2 ]. Here we report a novel clinical presentation of H. cinaedi infection: a case of fever in a returning traveler.…”