a-high-throughput-platform-for-screening-salmonella-sppshigella

A High-throughput Platform for the Screening of <em>Salmonella</em> spp./<em>Shigella</em> spp.

Fecal-oral transmission of acute gastroenteritis occurs from time to time, especially when people who handled food and water are infected by Salmonella ...

Zhuhai International Travel Healthcare Center

Norovirus is an important pathogen which accounts for majority of the viral related acute gastroenteritis. Recently, a variant of genotype GII.17 was reported to be predominant over GII.4 and accounted for several acute gastroenteritis outbreaks in Asia. In the current study, the full genome of a norovirus strain ZHITHC-12 isolated during this outbreak period in China was identified and characterized. The viral genome was 7557 nucleotides in length and a phylogenetic analysis based on full length genome sequences indicated that ZHITHC-12 belonged to GII.17 genotype. A further phylogenetic analysis based on all available polymerase and capsid sequences showed that ZHITHC-12 was in Cluster III on both phylogenetic trees and grouped with other strains also isolated during 2013 to 2015. Moreover, homology modeling analysis based on GII norovirus capsid 5BSX template revealed that substitutions, mutations, and more importantly, deletions and insertions, occurred at or near the putative epitopes and histo-blood group antigen (HBGA) binding sites in its protruding P2 domain, which might confer new antigenic or biological properties for this novel variant. In summary, the first full genome and capsid protein structure of a novel norovirus GII.17 variant isolated in China was extensively characterized. The data would be helpful not only for the epidemiology study, but also for the diagnostic tool development and effective vaccine design in the future. 

Complete nucleotide sequence analysis of the norovirus GII.17: A newly emerging and dominant variant in China, 2015.

Salmonella spp./Shigella spp. are often associated with food poisoning and fecal-oral transmission of acute gastroenteritis that requires strict monitoring, especially among people who would handle food and water. In 2014, the National Health and Family Planning Commission of the P. R. China issued a national standard protocol (recommendatory) for the screening of Salmonella spp./Shigella spp.. However, its performance has not been fully studied. Whether it was suitable for use in our laboratory was still unknown. In the current study, the new protocol was first verified by various experiments and then its clinical performance was evaluated in about 20,000 stool samples over a three-year period. Verification results showed that the new protocol was highly specific and reproducible. Sensitivity (as defined as the lower limit of detection) of the new protocol at the PCR step was 10CFU/mL and 10CFU/mL for Salmonella spp. and Shigella spp., while that at the guided culture step was 10CFU/mL and 10CFU/mL, respectively. The large scale clinical evaluation indicated that the new protocol could increase the positivity rate by two fold and decrease the workload/median turnaround time significantly. In conclusion, the protocol was verified and evaluated and was proven to be a valuable platform for the rapid, specific, sensitive and high-throughput screening of Salmonella spp./Shigella spp.

Verification and large scale clinical evaluation of a national standard protocol for Salmonella spp./Shigella spp. screening using real-time PCR combined with guided culture.

Article	Year
Complete nucleotide sequence analysis of the norovirus GII.17: A newly emerging and dominant variant in China, 2015. Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases\| PubMed ID: 26687061	2016
Verification and large scale clinical evaluation of a national standard protocol for Salmonella spp./Shigella spp. screening using real-time PCR combined with guided culture. Journal of microbiological methods\| PubMed ID: 29262293	2018

Cheng-Ning Tu

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