Characterization of oral microbiota of children with hand, foot, and mouth disease caused by enterovirus A 71.

Background: The association between alterations in the oral microbiome and hand, foot, and mouth disease (HFMD) has been observed in previous studies. Our study, therefore, aimed to identify the structural changes in the oral microbiota and biomarkers in children with HFMD caused by enterovirus A 71 (EV-A71).

Methods: Children diagnosed with EV-A71 HFMD and healthy children recruited from April 2021 to September 2023 were included in the present study, and were categorized into EV-A71 and control groups, respectively. Oral swabs were collected and microbiota information was obtained using 16 S rRNA gene sequencing technology. Alpha-diversity and partial least squares discriminant analyses were conducted to compare microbial diversity, richness, and similarity between the two groups. Linear discriminant analysis effect size was employed to identify microbial taxa with significant differences, and determined the key genera among them.

Results: The study included a total of 80 children, with 50 assigned to the EV-A71 group and 30 to the control group. No significant differences were found between the two groups in terms of age (2.2 ± 1.2 vs. 2.7 ± 1.2 years; age range: 1-5 years; P = 0.114) or sex (56% vs. 60% boys, P = 0.726). The oral microbiota structure in the EV-A71 group differed from that in the control group. The EV-A71 group showed significant reductions in both the Shannon index (P = 0.037) and the abundance-based coverage estimator (ACE) index (P < 0.001). The key genus changes were marked by a significant decrease in the abundance of Capnocytophaga (P = 0.002) and Leptotrichia (P = 0.033) in the EV-A71 group.

Conclusion: In children with EV-A71 HFMD, the oral microbiota showed changes in composition, with a significant reduction in diversity and richness. The changes in key genera were a marked decrease in the abundance of Capnocytophaga and Leptotrichia.