Clostridioides difficile can colonise infants without obvious symptoms. Does that mean the developing gut is unaffected? A September study in Science, available through its public abstract, examined that question. An NIH research account describes the experimental work. The two pages discuss the same study, rather than providing an independent replication.
The evidence for persistence comes principally from neonatal mice. Early colonisation prompted inflammatory and tissue repair responses in the intestinal epithelium, increased populations of injury-associated intestinal stem cells and shifted differentiation towards secretory cell lineages. Some epithelial changes remained detectable when the mice reached adulthood, although colonisation itself was transient. These findings suggest that transient colonisation can leave persistent epithelial changes in this mouse model.
Experiments associated the epithelial response with C. difficile toxins: colonisation by non-toxigenic strains did not produce the same response. The researchers also used laboratory-grown intestinal models. According to the abstract, human infant intestinal epithelial cells were sensitive to the toxins, while biopsies from colonised infants showed altered stem cell behaviour. These human observations offer a reason to investigate further; they do not measure whether colonised infants subsequently develop disease as adults.
The NIH account describes a further mouse experiment involving vaccination of females before they gave birth. Their newborns could still become colonised, but toxin levels were lower and the reported stem cell changes were prevented. Preventing a toxin-associated change in mice is different from preventing colonisation. It is also a long way from showing that a vaccine would benefit pregnant people or infants in clinical care.
The study broadens the question posed by apparently symptom-free colonisation to include the behaviour of the developing epithelium. Its lasting findings are mainly animal findings, with laboratory work and limited infant material addressing related mechanisms. The available abstract offers no reliable estimate of long-term human health risk. Human follow-up and further mechanistic work are needed before these results could inform routine screening or treatment of asymptomatic infants.
Cover: a 2019 medical illustration of C. difficile by Jennifer Oosthuizen / CDC, PHIL 23247; public domain, not a microscopy image from this study. The original is freely available. Use does not imply endorsement by CDC, HHS or the US Government. Image source · Licence
