ROLE OF INTESTINAL MICROBIOTA IN PERSISTENT TYPHOID CARRIERS

Abstract

Persistent Salmonella enterica serovar Typhi (S. Typhi) carriage represents a significant public health concern, particularly in endemic regions, as asymptomatic carriers continue to shed the pathogen long after clinical recovery. This study aimed to investigate the role of intestinal microbiota and gut virome in sustaining S. Typhi persistence post-infection.People from areas where S. Typhi infections are common and remain for a long time, along with non-carrier people, took part in a type of case-control study.  The stool samples were analyzed using viral metagenomics and 16S rRNA gene sequencing.  To analyze diversity, composition and phage infection, QIIME2, LEfSe and PICRUSt were applied; the acceptable threshold was p < 0.05. Persistent carriers had a significantly lower Shannon index for Alpha diversity (2.71 compared to 3.85, p < 0.001).  Different community structures could be seen through the beta diversity method.  The study identified that there was a fewer number of Lactobacillus and Bifidobacterium in carriers, even though LEfSe found more Desulfovibrio, Enterobacteriaceae and Bacteroides fragilis in them.  Research of the function showed that the sulphur metabolism and lipopolysaccharide production pathways were turned on more.  Due to an increase in virulence and resistance genes coming from tendentially integrated prophages, the study indicated a higher number and richness of Myoviridae and Siphoviridae viruses.  We observed that specific virulence-associated phages tend to be present with pathogenic bacteria in the carrier group.  Fun fact: Changes in the gut’s bacteria microbiota and more phages, possibly leading to higher bacterial virulence and survival in the body, are associated with persistent S. Typhi carriage.  The findings suggest that the microbiota-virome-immune axis greatly influences long-term possession and suggest different ways to treat it, including controlling phage activity or restoring the microbiome.