Introduction Diabetes remains a growing public health concern in Egypt, as prevalence of Type II diabetes (TIID) has nearly tripled there in the last two decades. Egypt was ranked ninth worldwide in number of diabetes cases, with prevalence of 15.56% among adults. Recent studies have proposed that disturbance of gut microbiota could influence TIID development and indicated associations between a reduced diversity in microbiomes and Type I diabetes (TID). In the present study, we investigated the composition and abundance of the bacterial microbiome in disease state (TID and TIID) of Egyptian patients. Our goal in this study was to characterize features of the gut microbiota and possible differences associated with TID and TIID in this population. Methods DNA was extracted from fecal samples taken from 22 TID and 18 TIID outpatients of Al-Hussein hospital, Cairo, Egypt. 16S rRNA amplicon sequencing was used to characterize the bacterial taxa and these reads were processed using the software mothur with analysis utilizing packages vegan, phyloseq and metagenomSeq in R. Results and conclusions Our results highlighted a significant increase in abundance of Gram negative, potentially opportunistic pathogenic taxa (Pseudomonas, Prevotella) in all diabetic groups, compared to the control. Lipopolysccharide (LPS), a component of the gram-negative bacterial wall, can activate local immune response and may result in low-grade systemic inflammation contributing to insulin resistance. The gram-positive Gemella, which is associated with increased risk to diabetes, also had a significant increase in abundance in all diabetic groups, compared to the control. In contrast, the commensal bacterial taxa Turicibacter, Terrisporobacter and Clostridium were found to be more abundant in the control group than

Unique to mucosal vaccination is the reciprocal influence of the microbiome and mucosal immune responses, where the immune system is constantly balancing between the clearance of pathogens and the tolerance of self-antigen, food, and the microbiota. Secretory IgA plays a major role in maintaining the homeostasis of a healthy gut microbiome. Natural polyreactive IgA often coats members of the commensal microbiota to aid in their colonization, while high-affinity specific IgA binds to pathogens resulting in their clearance. We developed a probiotic-based mucosal vaccination platform using the bacterium Lactobacillus acidophilus (rLA) with the potential to influence this balance in the IgA coating. In this study, we sought to determine whether repeated administration of rLA alters the host intestinal microbial community due to the immune response against the rLA vaccine. To address this, IgA-seq was employed to characterize shifts in IgA-bound bacterial populations. Additionally, we determined whether using rice bran as a prebiotic would influence the immunogenicity of the vaccine and/or IgA-bound bacterial populations. Our results show that the prebiotic influenced the kinetics of rLA antibody induction and that the rLA platform did not cause lasting disturbances to the microbiome.