Genome-wide analysis provides a deeper understanding of the population structure of the Salmonella enterica serotype Paratyphi B complex in Bangladesh

The Salmonella enterica serotype Paratyphi B complex causes a wide range of diseases, from gastroenteritis to paratyphoid fever, depending on the biotypes Java and sensu stricto. The burden of Paratyphi B biotypes in Bangladesh is still unknown, as these are indistinguishable by Salmonella serotyping. Here, we conducted the first whole-genome sequencing (WGS) study on 79 Salmonella isolates serotyped as Paratyphi B that were collected from 10 nationwide enteric disease surveillance sites in Bangladesh. Placing these in a global genetic context revealed that these are biotype Java, and the addition of these genomes expanded the previously described PG4 clade containing Bangladeshi and UK isolates. Importantly, antimicrobial resistance (AMR) genes were scarce amongst Bangladeshi S. Java isolates, somewhat surprisingly given the widespread availability of antibiotics without prescription. This genomic information provides important insights into the significance of S. Paratyphi B biotypes in enteric disease and their implications for public health.

Development of a PCR test system for specific detection of Salmonella Paratyphi B in foods

Salmonella enterica serotype Paratyphi B is a globally distributed human-specific pathogen causing paratyphoid fever. The aim of this study was to develop a rapid and reliable polymerase chain reaction (PCR) assay for its detection in food. The SPAB_01124 gene was found to be unique to S. Paratyphi B using comparative genomics. Primers for fragments of the SPAB_01124 gene and the Salmonella-specific invA gene were used in combination to establish a multiplex PCR assay that showed 100% specificity across 45 Salmonella strains (representing 34 serotypes) and 18 non-Salmonella strains. The detection limit was 2.2 CFU mL(-1) of S. Paratyphi B after 12-h enrichment in pure culture. It was shown that co-culture with S. Typhimurium or Escherichia coli up to concentrations of 3.6 × 10(5)  CFU and 3.3 × 10(4)  CFU, respectively, did not interfere with PCR detection of S. Paratyphi B. In artificially contaminated milk, the assay could detect as few as 62 CFU mL(-1) after 8 h of enrichment. In conclusion, comparative genomics was found to be an efficient approach to the mining of pathogen-specific target genes, and the PCR assay that was developed from this provided a rapid, specific, and sensitive method for detection of S. Paratyphi B.

A case report of acute acalculous cholecystitis due to Salmonella Paratyphi B complicated by biliary peritonitis

Non-typhoidal salmonella are a rare case of acute acalculouscholecystitis (AAC). Salmonella Paratyphi B, which accounts for one of the less invasive NTS serotypes, has rarely been reported to cause cholecystitis. We describe a case of 65-year old previously healthy man, who present with signs of acute abdomen, due to biliary peritonitis as a complication of acute acalculouscholecystitis caused by Salmonella paratyphi B. Our case illustrates the potential severity of infection with Salmonella Paratyphi B especially in older patient. High index of awarenessshould be considered in endemic areas.

Salmonella Paratyphi B septicemia in a Neonate

Septicemia is a major cause of death in neonates especially in developing countries. We report a case of septicemia in a neonate due to Salmonella Paratyphi B. The baby responded well to therapy and recovered completely.

Salmonella paratyphi B meningitis in an infant

We report a case of Salmonella paratyphi B meningitis in a 90 day-old male infant who was admitted with complaints of fever, vomiting and one episode of vacant stare. Clinically, the infant was found to be toxic and dull with a bulging anterior fontanelle. Subsequently, blood and cerebrospinal fluid cultures demonstrated the presence of Salmonella Paratyphi B organism.