Infect. Immun. doi:10.1128/IAI.00558-09 (2009)

Clostridium difficile, a spore-forming anaerobic bacterium that inhabits the gut of as many as 5% of humans, is a leading cause of antibiotic-induced diarrhoea. When a carrier takes antibiotics, these can wipe out other gut microbiota and send C. difficile into overdrive, which can lead to rampant spread of the bacterium in hospital settings. Trevor Lawley of the Wellcome Trust Sanger Institute in Hinxton, UK, and his colleagues have developed a new mouse model for the condition.

Between two and three days after treatment with the antibiotic clindamycin, mice carrying C. difficile shed a million-fold more spores in their faeces than before. More than half of the mice retained this 'supershedder' status for several weeks. Uninfected mice housed with supershedders became carriers themselves; because the bacterial spores are ethanol resistant, cages had to be thoroughly cleaned with sporicides.