Speaker: Susannah Salter, Advanced Research Assistant, Wellcome Sanger Institute, will present a seminar entitled:

Unculturable bugs hiding in plain sight: a potential pathogen and a cautionary tale

Host: Andrew Page

Abstract:
Human microbiome research has been revolutionised by culture-independent methods, allowing us to observe species that do not grow easily in lab conditions (so-called “unculturable” bacteria). It seems that new discoveries and controversies arise every week. But should we take our metagenomic data at face value?

Low biomass samples such as from skin, blood, or sites that are traditionally thought to be sterile, pose a significant problem for deep sequencing. Contamination of a sample at any point in the workflow will introduce DNA that may overwhelm the true signal. Although it is often possible to identify and remove this from the data, misinterpreted contamination is gaining influence in the microbiome literature.

In light of this widespread DNA contamination issue, common sense plays a crucial role in the interpretation of data. So how plausible is it to find a new species of bacteria in a well-studied niche, apparently colonising people around the world, that has never been characterised? The 1.9Mb genome of Ornithobacterium hominis was extracted from short read metagenomic sequence data in lieu of pure culture: it is a persistent coloniser that is highly prevalent in the study population and encodes a toxin similar to the dermonecrotic mitogenic toxin of Pasteurella multocida.

All staff from organisations on the Norwich Reseasrch Park are wlcome to attend.