Heterogeneity ofClostridium difficile isolates from infants

Abstract

In order to improve our understanding of the role of Clostridium difficile in infants we characterised the strains isolated from this population. The production of toxin A and toxin B was studied. The toxin A, playing a major role in the disease, was searched for in faecal samples. The serogroup of the isolates was determined because some serogroups have been shown to be more pathogenic than others. Over a 9-month period, 102 faecal samples from 102 hospitalised infants (0-12 months) were analysed and 26% of the children were colonised with C. difficile. Fifteen isolates secreted neither toxin A nor B (62.5%). Nine isolates were toxigenic and secreted both toxins (37.5%). Of the eight toxigenic strains tested, six were from serogroup H and two serogroup K. Of the 13 nontoxigenic strains tested, 8 belonged to serogroup D, 2 to serogroup X, and 1 each to serogroup A, serogroup B and serogroup C. Three infants out of 102 studied had toxin A in their faeces. In summary, the infants can be colonised by (1) nontoxigenic strains, most of them from nonpathogenic serogroup D, without toxin A in the faeces; (2) toxigenic strains of virulent serogroups H and K, with or without toxin A in the faeces. Although some infants had diarrhoea, none needed a specific treatment for C. difficile. No specific C. difficile pathology could be retained and different mechanisms are advanced to explain this absence of pathogenicity.

Clostridium difficile and the microbiota

“…C. difficile spores have been detected in various environmental sources, including domesticated animals, water sources, and soil (13). Another potential reservoir of C. difficile resides in the infant population, in which colonization is estimated to occur in up to 45% of individuals (14,15). The infant microbiome is distinct from adults', and differences in the microbiome may be important in both colonization and disease resistance (16,17).…”

Structural and functional changes within the gut microbiota and susceptibility to Clostridium difficile infection

“…Low microbial diversity and asymptomatic carriage of toxigenic C. difficile is also prevalent during the first year of life (68–71) when the gut microbiome is dominated by Bifidobacterium and Lactobacillus (72–75). Although passive transfer of maternal antibodies (76, 77) and a lack of toxin receptors have been proposed (78), the mechanism for asymptomatic C. difficile carriage in this population remains unknown.…”

Toxin-Producing Clostridium difficile Strains as Long-Term Gut Colonizers in Healthy Infants

“…Colonization in infants is much more common, but also variable, and 25 to 80% of infants harbor C. difficile (10)(11)(12)(13). The high carriage rate in infancy has been ascribed to the low capacity of the infantile gut microbiota to suppress the growth of C. difficile.…”