Epidemiology of Helicobacter pylori infection.

The study of Helicobacter pylori genetic variability brought us interesting data on the history of mankind. Based on multilocus sequence typing and more recently on whole-genome sequencing, paleomicrobiology still attracts the attention of global researchers in relation to its ancestor roots and coexistence with humans. Three studies determining the prevalence of virulence factors illustrates the controversial results obtained since 30 years by studies trying to associate prevalence of different virulence markers and clinical outcomes of H. pylori infection. Three articles analyzed the prevalence and risk of multiple (genetically distinct isolates) and mixed (susceptible and resistant isolates) infections. A number of studies confirm that H. pylori prevalence is falling worldwide especially in the developed world and in children but that the level of infection is higher in certain ethnic minorities and in Migrants. There is little new in identifying the mode of H. pylori transmission though intrafamilial spread appears to be important. There have, however, been some interesting papers on the presence of the organism in food, water, and the oral cavity.