Development of a PCR test system for specific detection of Salmonella Paratyphi B in foods
2014
Zhai, Ligong | Yu, Qian | Bie, Xiaomei | Lu, Zhaoxin | Lv, Fengxia | Zhang, Chong | Kong, Xiaohan | Zhao, Haizhen
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⁻¹of 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 × 10⁵ CFU and 3.3 × 10⁴ 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⁻¹after 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.
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