ABSTRACT
The role of the gut microbiota in triggering autism is a rapidly emerging field of research. Gut microbiota have been incriminated because autistic children often have gastrointestinal symptoms. Pathogenic gut bacteria in children with autism spectrum disorders (ASD) have been reported. The present study aimed to assess Clostridium difficile in the stool of children with ASD and its relation to gastrointestinal (GI) comorbidities, autism severity, and sensory impairment. The study included 58 ASD patients, 45 of their neurotypical siblings, and 45 unrelated controls. Childhood Autism Rating Scale (CARS) was used to assess the severity of autism. Sensory problems were evaluated using the Short Sensory Profile (SSP). GI symptoms were assessed with a modified six-item GI Severity Index (6-GSI) questionnaire. Quantitative real-time PCR was done for the detection and quantitation of C. difficile and its toxins A and B. C. difficile was detected in 25.9%, 40%, and 15.6% of ASD cases, siblings, and unrelated control respectively. Regarding toxin A and B production, 73.3%, 77.8%, and 71.4% of C. difficile in positive ASD, siblings, and unrelated control cases respectively were toxigenic. There was no statistically significant difference between the three groups as regards C. difficile qualitative, quantitative, and toxin production results. In conclusion, C. difficile is not specifically prevalent in the gut of children with ASD. Although most of the strains are toxigenic, there were no GI symptoms in the control groups and no statistically significant association with GI Severity Index in autistic cases. Gastrointestinal dysfunction and sensory impairment are common comorbidities in ASD.
Subject(s)
Autism Spectrum Disorder/complications , Clostridioides difficile/isolation & purification , Gastrointestinal Diseases/etiology , Gastrointestinal Microbiome , Sensation Disorders/etiology , Autism Spectrum Disorder/microbiology , Bacterial Proteins/analysis , Bacterial Toxins/analysis , Child , Child, Preschool , Clostridioides difficile/pathogenicity , Comorbidity , Enterotoxins/analysis , Feces/microbiology , Female , Gastrointestinal Diseases/microbiology , Humans , Male , Real-Time Polymerase Chain Reaction , Sensation Disorders/microbiology , Severity of Illness Index , SiblingsABSTRACT
The role of gut microbiome was recently raised in the pathogenesis of neurodevelopmental disorders including autism spectrum disorder (ASD). The aim of this study was to elucidate changes in gut microbiome in Egyptian autistic children and its possible correlation with the severity of autism and gastrointestinal (GI) symptoms. The gut bacterial microbiome of 41 ASD children, 45 siblings, and 45 healthy controls were analyzed using quantitative SYBR Green real-time PCR technique targeting 16S rRNA of selected bacteria. The gut microbiome of ASD children and their siblings contained a higher relative abundance of Bacteroides as well as Ruminococcus than controls. Prevotella/Bacteroides (P/B) ratio and Firmicutes/Bacteroidetes (F/B) were significantly lower in both ASD cases and their siblings. The only difference between the autistic cases and their siblings was the significantly higher level of Bifidobacterium in siblings, which appears to offer them a protective role. There was no correlation between the altered gut microbiome and the severity of autism or GI symptoms. The current study showed an evidence of changes in the gut microbiome of autistic children compared to the unrelated control. However, the microbiome profile of siblings was more like that of autistic children than that of unrelated controls indicating that gut microbiota is affected by dietary habits, living conditions together with host genetic factors.
