Lactobacilli Profile in Faecal Samples of Tunisian Children Diagnosed with Autism Spectrum Disorder

Abstract

Alterations in faecal lactobacilli in autistic children have been reported, but little is known related to age and disorder severity. We used a culture-based method and partial 16S rRNA gene sequencing to isolate and identify lactobacilli strains from faeces of Tunisian autistic children (ASD group) and compared them with strains isolated from siblings (SIB) and children from the general population (GP). The ASD group displayed an increased number of different species compared to SIB and GP. Differences in species abundance with age accounted for a significant decrease in the abundance of Lactiplantibacillus plantarum/Lactiplantibacillus pentosus isolates in the GP at the age of 8–10 years compared to the age of 4–7 years, and to a significantly lower abundance of Lacticaseibacillus rhamnosus in the ASD group with respect to SIB and the GP at the age of 8–10 years. Simpson’s and Shannon–Wiener indices showed a more pronounced species diversity increase with age in the GP group compared to the ASD and SIB groups. Minor differences were found in lactobacilli prevalence and in species diversity between children with severe and mild-to-moderate ASD. Overall, we found substantial differences in the profile of faecal lactobacilli species in the ASD and GP groups at the age of 8–10 years.