Industry of interest: Healthcare
Microbiology: Helicobacter pylori is a Gram-negative, helix-shaped microaerophilic organism. The organism is highly specialised to exist within the acidic environment of the stomach. H. pylori can change its membrane potential at external pH levels from 3-7 in order to maintain its neutral internal pH (Vandenplas, 1999). The organism uses virulence factors such as urease and its flagella to establish and infection and can use molecular mimicry to evade the host immune response.
Habitat and transmission: The exact mode of transmission of H. pylori is not fully understood. Some have suggested that flies, pets and water may be responsible for transmitting the microorganism (Vandenplas, 1999). However faecal-oral and gastro-oral routes are seen to be the most likely modes of transmission (Tan and Wong, 2011). H. pylori is generally acquired in childhood, and natural acquisition of the organism as an adult is rare (Tan and Wong, 2011). Risk factors for colonisation include poor socio-economic status, low levels of sanitation, household hygiene and genetic pre-disposition (Tan and Wong, 2011).
Treatment and antibiotic resistance: The treatment for H. pylori infection is a triple therapy of 2 antibiotics and a proton pump inhibitor (O’Connor et. al., 2010). Generally the triple therapy contains clarithromycin and another antibiotic or bismuth containing drug. Compliance of this triple therapy treatment of H. pylori infection is poor; this is thought to be due to the side effects of some of the drugs (Vandenplas, 1999). The poor compliance with the triple therapy has also led to an increase in antibiotic resistance of H. pylori strains, particularly to clarithromycin (O’Connor et. al., 2010). This had led to a reduction in the efficacy of triple H. pylori therapy.
Prevention and control:As the exact method of transmission is not known it is difficult to ascertain the best methods to prevention H. pylori infection. However, improvements in hygiene and sanitation will go some way to reducing incidence of infection. Improvements in compliance with antibiotic regimens will prevent further antibiotic resistance from occurring, thus improving patient outcomes. A H. pylori vaccine is currently under development.
Disease and symptoms: People can be colonised by H. pylori and never have any symptoms of infection. However infection usually begins with acute gastritis and the large majority of cases then proceed to a chronic active gastritis (Tan and Wong, 2011). Further disease symptoms include duodenal ulcers, multifocal atrophic gastritis, gastric cancers and in rare cases lymphoma (Tan and Wong, 2011).
O’Connor A., Gisbert J.P., McNamara D. And O’Morain C. (2010) Treatment of Helicobacter pylori infection 2010. Helicobacter. 15(Suppl 1): 46-52.
Tan V.P. and Wong B.C. (2011) Helicobacter pylori and gastritis: untangling a complex relationship 27 years on. J Gastroenterol Hepatol. 26(Suppl 1): 42-45.
Vandenplas Y. (1999) Helicobacter pylori infection. Clin Microbiol Infect. 5: 1-11.