“Molecular and Epidemiologic Methods for Study of Helicobacter pylori Transmission”
Helicobacter pylori, one of the most common bacterial pathogens of humans, is responsible for a range of disease outcomes from asymptomatic gastritis to peptic ulcers and gastric cancers. Infection is generally acquired in childhood and can persist for the lifetime of the infected host. H. pylori has many mechanisms for genetic diversification, which likely aids the bacterium in adapting to a new host. H. pylori transmission predominantly occurs within families; however, it is not known if this is because of the close contacts that occur within families or because an H. pylori strain that is adapted to the individual host is better able to colonize a genetically similar host. Transmission can be traced by genotyping H. pylori to determine whether individuals share the same H. pylori strain, evident by shared nucleotide sequence at defined loci or shared gene content. My proposed research incorporates molecular biology and epidemiology to develop methods for studying the transmission of H. pylori. The first aim involves optimizing a non-invasive method for genotyping H. pylori from stool DNA, which allows for epidemiologic studies that sample asymptomatic individuals to test for H. pylori infection and track its spread. The second aim is a pilot epidemiologic study that involves collecting stool samples from families with biological children and families with adopted children and using the H. pylori genotyping method developed in Aim 1 to examine H. pylori transmission within families.