Review: Gastric and enterohepatic helicobacters other than Helicobacter pylori – The evolving importance of Non-Helicobacter pylori Helicobacter species for public and animal health

Abstract

From April 2022 to March 2023, a lot of new evidence was published concerning non-Helicobacter pylori Helicobacter (NHPH) species and their significance for public and animal health. Five new enterohepatic Helicobacter species were described, including H. anatolicus and H. kayseriensis in urban wild birds, H. turcicus in Anatolian ground squirrels, H. colisuis in domestic pigs and H. kumamotonensis in a human patient. Also, the genomic difference between the human-associated H. cinaedi and animal-associated H. canicola was established. A potential pathophysiological role for gastric NHPHs was revealed in a Western H. pylori-negative cohort study of patients with gastric symptoms, and many case reports were published regarding enterohepatic Helicobacter bacteremia in human patients. The public health significance of H. pullorum was also an important topic. The significance of gastric and enterohepatic Helicobacter infections in animals and the importance of animals as reservoirs were further investigated with cohort studies in pigs and wild boars, dogs, cats, non-human primates, wild mice, and poultry. Experimental infection with NHPHs was still frequently used in several mouse models. In multiple in vivo studies, changes in the relative abundance of enterohepatic Helicobacter species related to gut microbiota alterations were observed. Novel diagnostic tests were developed, and novel therapeutic strategies were explored in the fight against antibiotic resistance. Finally, new insights into potentially important proteins and virulence mechanisms were obtained.

Keywords

• gastric helicobacter species
• enterohepatic helicobacter species
• non-helicobacter pylori helicobacter
• animal model
• zoonosis
• pathogenesis
• microbiota.