Evaluation of pathogenicity, characteristics, mode of transmission, and host association of some important Helicobacter species

Evaluation of pathogenicity, characteristics, mode of transmission, and host association of some important Helicobacter species
Fatemeh Akhlaghi,^1,*
1. Shahed school
Introduction: Recently, the genus Helicobacter includes 54 identified species. This genus can be divided into two major groups, comprising gastric and enterohepatic species. Specifically, the gastric Helicobacter species can survive in the acidic environment of stomach. However, the enterohepatic Helicobacter species can survive in the mucosal surface of intestinal tract and liver. This review article generally aimed to discuss and describe the biology and pathogenesis of two critically important Helicobacter species, including Helicobacter pylori, as a gastric species, and Helicobacter pullorum, as an enterohepatic species, in humans and animals.
Methods: H. pylori, first being discovered in 1982 from human, has been categorized as a class 1 carcinogen by the International Agency for Research on Cancer (IARC). Notably, epidemiological studies have exhibited that almost 50 per cent of the population are infected by this zoonotic pathogen worldwide. But, just a portion of infected individuals have been implicated in a wide spectrum of gastric disorders that can lead to Peptic Ulcer Disease (PUD) or Gastric Cancer (GC). In Iran, for instance, it has been estimated that more than 90% of population does seem to be infected with this gram negative species. In developing countries, H. pylori infection mainly occurs in childhood and infected people may carry this bacterium in their stomach for lifelong. Obviously, there have been several risk factors being associated with the transmission of H. pylori to humans, namely consumption of uncooked milk, vegetables, and meats, the presence of domestic animals, the presence of rodents near or in the houses, the contact with pets, and so on.
Results: H.pullorum, first being discovered in 1994 from intestinal contents of chicken and laying hens, has been taken into account as an emerging foodborne human pathogen which can pose a perilous risk to public health. Most of the poultry, such as chicken, turkey, laying hen, human, meat, and even water could be said as a source of contamination for this gram negative bacterium. Importantly, the fact that the Iranian poultry industry has become the first in the Middle East and 7th throughout the world by producing 2 million metric tons of chicken meat, has given importance to this life-threatening pathogen. There have been some significant human diseases being linked to this non-spore forming bacterium, namely gastroenteritis, inflammatory bowel disease, hepatobiliary disease, Crohn, s disease, and so on.
Conclusion: To sum up, in this review article we attempted to reveal the lifestyle of two significant Helicobacter species, including H. pylori and H. pullorum. In fact, considering these foodborne pathogens would be of utmost importance and therefore more elaborate studies are needed to discuss about the mentioned pathogens.
Keywords: review article, Helicobacter pylori, Helicobacter pullorum, pathogenicity