Salmonella enterica serovar Paratyphi (S. Paratyphi)

Salmonella enterica serovar Paratyphi is a Gram-negative, flagellated, rod-shaped bacterium that serves as the primary causative agent of paratyphoid fever (StatPearls, 2023). This systemic illness is clinically similar to typhoid fever and is transmitted via the fecal-oral route through contaminated food and water (CDC, 2023). Upon ingestion, the bacteria invade the intestinal mucosa and are internalized by macrophages, where they survive and replicate within specialized compartments called Salmonella-containing vacuoles (PubMed, 2015). The pathogen then disseminates through the reticuloendothelial system to the liver, spleen, and bone marrow, leading to sustained bacteremia (WHO, 2023). Treatment typically involves antimicrobial therapy with fluoroquinolones, macrolides, or third-generation cephalosporins, which target bacterial DNA replication and protein synthesis (StatPearls, 2023). However, the emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains has become a significant therapeutic challenge, often requiring susceptibility testing to guide effective treatment (CDC, 2023).

Other names

Paratyphoid bacillusSalmonella enterica subsp. enterica serovar Paratyphi ASalmonella enterica subsp. enterica serovar Paratyphi BSalmonella enterica subsp. enterica serovar Paratyphi CSalmonella paratyphiParatyphoid fever bacterium

Antibiotics targeting Salmonella Paratyphi act through various mechanisms: fluoroquinolones (e.g., Ciprofloxacin) inhibit DNA gyrase and topoisomerase IV to prevent DNA replication; macrolides (e.g., Azithromycin) bind to the 50S ribosomal subunit to inhibit protein synthesis; cephalosporins (e.g., Ceftriaxone) and penicillins (e.g., Amoxicillin) inhibit bacterial cell wall synthesis by binding to penicillin-binding proteins; and sulfonamides inhibit the synthesis of dihydrofolic acid (StatPearls, 2023; CDC, 2023).