Infant Botulism and Carbohydrate Blood Group Antigens: Preliminary Results from a Discordant Twin Study

We investigated if specific carbohydrate blood group antigens were associated with infant botulism (IB) among discordant twins and triplets.

Infants in the US and Canada from 2015 to 2022 who had laboratory-confirmed IB; were members of a multiple gestation birth; and had unaffected sibling(s), were eligible to participate. Blood specimens were tested for ABO, Lewis, H, and P1 carbohydrate blood antigens. FUT2 and FUT3 genes were sequenced to determine secretor and Lewis antigen status, respectively. In addition, characteristics of IB cases in the study were compared to the singleton US-Canadian IB cases from 2015 to 2022.

Parents of 14 of 26 IB cases who were twins or triplets with unaffected siblings consented to participate. No statistically significant associations between blood group antigens (ABO, Lewis, H, and P1) and IB were demonstrated. Twin cases in this study were significantly younger at onset of illness (median age 8.6 vs 17.3 weeks for the singleton US-Canadian IB cases, t test P < .001); and less likely to be fed exclusively breastmilk (14% for twin vs 63% for the US-Canadian IB cases) and more likely to be mixed-fed breast milk and formula (86% for twin vs 23% for the US-Canadian IB cases, Fisher exact test P < .001).

In this first-of-its-kind small study of IB twin or triplet cases and their unaffected siblings, no carbohydrate blood group antigens were associated with IB. Future studies could compare the microbial composition of the gut microbiome of IB cases and uninfected twin siblings or the prevalence of ABO blood groups in IB cases vs population norms.