The silent burden of neonatal C. difficile colonisation and contamination

We worry often about asymptomatic colonisation (aka ‘silent carriage’) of a range of hospital pathogens MRSA, VRE, CRE but not C. diff. Screening for C. diff colonisation in the absence of diarrhoea is rarely performed. One of the interesting nuances of C. diff ecology is the high rate of colonisation in babies. A US study surveyed the rate of asymptomatic C. diff carriage and environmental contamination in a neonatal intensive care unit (NICU). 9 (26%) of the 35 babies sampled were asymptomatic carriers, which is no surprise and in line with other studies. The levels of environmental contamination identified were actually pretty low. Only 2 (1.7%) of 120 sites sampled yielded C. diff in samples collected from the NICU, paediatric units and a haematology / oncology unit. More focussed sampling in the NICU did identify a higher rate environmental contamination with half of the ‘diaper’ (aka nappy) scales contaminated. It’s not clear why the levels of environmental C. diff identified in this study were lower than in others. Perhaps the hospital had C. diff pretty much under control? Perhaps the lab methods were not optimal? Either way, the levels of contamination identified in the NICU are consistent with the levels of asymptomatic colonisation, and a potential risk for onward transmission. So, should we start routinely sampling patients without diarrhoea for C. diff carriage? Should we start routinely sampling their environment? The jury is out on these questions, but asymptomatic carriers of C. diff can certainly be a source of environmental contamination.