Salmonella enterica serotype Typhi (S. Typhi)

Salmonella enterica serotype Typhi is a Gram-negative, flagellated, rod-shaped bacterium that is the causative agent of typhoid fever, a systemic and potentially fatal human-restricted infection (StatPearls, 2023). It is primarily transmitted through the fecal-oral route via contaminated food or water (WHO, 2023). Once ingested, the bacterium invades the intestinal epithelium and is transported by macrophages to the reticuloendothelial system, including the liver, spleen, and bone marrow (PubMed, PMID: 25139252). S. Typhi utilizes unique virulence factors like the Vi capsular polysaccharide to evade host immune detection and the typhoid toxin to alter host cell physiology (Nature Reviews Microbiology, 2015). While traditionally treated with antibiotics such as fluoroquinolones and cephalosporins, the rise of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains has complicated therapeutic strategies (CDC, 2024). Prevention is managed through sanitation improvements and the administration of vaccines, such as the Vi capsular polysaccharide vaccine and the Ty21a live-attenuated vaccine (NIH, 2022).

Other names

Salmonella typhiEberthella typhiBacillus typhosusTyphoid bacillus

Antibiotics targeting this organism act through various mechanisms including inhibition of DNA gyrase and topoisomerase IV (fluoroquinolones), inhibition of the 50S ribosomal subunit (macrolides), and inhibition of cell wall peptidoglycan synthesis (beta-lactams) (StatPearls, 2023).