Helicobacter

Comparative genomic analysis has led to the identification of 11 proteins that are uniquely found in the Helicobacteraceae. Of these proteins, seven are found in all species of the family, while the remaining four are not found in any Helicobacter strains and are unique to Wollinella. Additionally, a rare genetic event has led to the fusion of the rpoB and rpoC genes in this family, which is characteristic of them.{{cite journal |author1=Zakharova N. |author2=Paster B. J. |author3=Wesley I. |author4=Dewhirst F. E. |author5=Berg D. E. |author6=Severinov K. V. |year = 1999 |title = Fused and overlapping rpoB and rpoC genes in Helicobacters, Campylobacters, and related bacteria |journal = J Bacteriol |volume = 181 |issue=12 |pages = 3857–3859 |doi=10.1128/JB.181.12.3857-3859.1999 |pmid=10368167 |pmc=93870 }}

Recently, new gastric (H. suis and H. baculiformis) and enterohepatic (H. equorum) species have been reported. H. pylori is of primary importance for medicine, but non-H. pylori species, which naturally inhabit mammals (except humans) and birds, have been detected in human clinical specimens. These encompass two (gastric and enterohepatic) groups, showing different organ specificity. Importantly, some species, such as H. hepaticus, H. mustelae, and probably H. bilis, exhibit carcinogenic potential in animals. They harbour many virulence genes and may cause diseases not only in animals, but also in humans. Gastric species such as H. suis (most often), H. felis, H. bizzozeronii, and H. salomonis have been associated with chronic gastritis and peptic ulcers in humans, and importantly, with higher risk for MALT lymphoma compared to H. pylori.

Enterohepatic species e.g., H. hepaticus, H. bilis, and H. ganmani, have been detected by PCR, but still are not isolated from specimens of patients with hepatobiliary diseases. Moreover, they may be associated with Crohn's disease and ulcerative colitis. The significance of avian helicobacters (H. pullorum, H. anseris, and H. brantae) also has been evaluated extensively. H. cinaedi and H. canis can cause severe infections, mostly in immunocompromised patients with animal exposure. Briefly, the role of these species in veterinary and human medicine is increasingly recognised. Several other topics such as isolation of still uncultured species, antibiotic resistance, and treatment regimens for infections and pathogenesis and possible carcinogenesis in humans should be evaluated.

Helicobacter heilmannii sensu lato (i.e. H. heilmanni s.l.) is a grouping of non-H. pylori Helicobacter species that take as part of their definition a similarity to H. pylori in being associated with the development of stomach inflammation, stomach ulcers,{{cite journal |vauthors = Bento-Miranda M, Figueiredo C |title = Helicobacter heilmannii sensu lato: an overview of the infection in humans |journal = World Journal of Gastroenterology |volume = 20 |issue = 47 |pages = 17779–87 |date = December 2014 |pmid = 25548476 |pmc = 4273128 |doi = 10.3748/wjg.v20.i47.17779 |doi-access = free }} duodenum ulcers,{{cite journal |vauthors = Iwanczak B, Biernat M, Iwanczak F, Grabinska J, Matusiewicz K, Gosciniak G |title = The clinical aspects of Helicobacter heilmannii infection in children with dyspeptic symptoms |journal = Journal of Physiology and Pharmacology |volume = 63 |issue = 2 |pages = 133–6 |date = April 2012 |pmid = 22653899 }} stomach cancers that are not lymphomas, and extranodal marginal B cell lymphoma of the stomach in humans and animals. Most clinical studies have not identified the exact species of H. heilmanii associated with these diseases, so designated these species as H. heilmanni s.l. However, investigative studies have identified these species in some patients with the cited H. heilmanni s.l.-associated upper gastrointestinal tract diseases. The H. heilmani species identified to date in the stomachs of humans with the cited upper gastrointestinal tract diseases are: Helicobacter bizzozeronii, Helicobacter felis, Helicobacter salomonis, Helicobacter suis, and Helicobacter heilmannii s.s. It is important to recognize the association of H. heilmannii sensu lato with these upper gastrointestinal tract diseases, particularly extranodal marginal zone lymphoma of the stomach, because some of them have been successfully treated using antibiotic-based drug regimens directed against the instigating H. heilmannii sensu lato species.{{cite journal |vauthors = Ménard A, Smet A |title = Review: Other Helicobacter species |journal = Helicobacter |volume = 24 |pages = e12645 |date = September 2019 |issue = Suppl 1 |pmid = 31486233 |doi = 10.1111/hel.12645 |doi-access = }} The H. heilmanni s.l.-associated human diseases appear to be acquired from pets and farm animals, so are considered to be zoonotic diseases.

The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN){{cite web| author=A.C. Parte| url=https://lpsn.dsmz.de/genus/helicobacter| title=Helicobacter| access-date=2023-09-09| publisher=List of Prokaryotic names with Standing in Nomenclature (LPSN)| display-authors=et al.}} and National Center for Biotechnology Information (NCBI){{cite web| author=Sayers| url=https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Undef&id=209&lvl=3&keep=1&srchmode=1&unlock| title=Helicobacter| access-date=2023-09-09| publisher=National Center for Biotechnology Information (NCBI) taxonomy database| display-authors=et al.}}

Species incertae sedis:

• "Ca. H. bovis" De Groote et al. 1999
• "H. callitrichis" Won et al. 2007
• "Ca. H. cebus" Gueneau de Novoa et al. 2001a
• "H. higonensis" Tomida et al. 2024
• "H. muricola" Won et al. 2002
• "H. peregrinus" Coldham et al. 2004
• "H. suncus" Goto et al. 1998
• "H. tursiopsae" Gueneau de Novoa et al. 2001b
• "H. vulpecula" Coldham et al. 2004

• List of bacterial orders
• List of bacteria genera

{{Reflist}}

• [https://patricbrc.org/view/Taxonomy/209#view_tab=overview Helicobacter] genomes and related information at [http://patricbrc.org/ PATRIC], a Bioinformatics Resource Center funded by [http://www.niaid.nih.gov/ NIAID]
• [https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Tree&id=209&lvl=3&lin=f&keep=1&srchmode=1&unlock List of species in Helicobacter, with links to sequence information]
• [http://bacdive.dsmz.de/index.php?search=Helicobacter&submit=Search Helicobacter at BacDive - the Bacterial Diversity Metadatabase]

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Category:Conditions diagnosed by stool test

Category:Gastroenterology

Category:Gram-negative bacteria

Category:Pathogenic bacteria

Category:Campylobacterota

Category:Bacteria genera