Culturable bacteria resident on lettuce might contribute to accumulation of human noroviruses

Danlei Liu; Zilei Zhang; Ningbo Liao; Songyan Zou; Haoxuan Tang; Peng Tian; Glenn M Young; Qingping Wu; Dapeng Wang

doi:10.1016/j.ijfoodmicro.2019.108492

Culturable bacteria resident on lettuce might contribute to accumulation of human noroviruses

Int J Food Microbiol. 2020 Mar 16:317:108492. doi: 10.1016/j.ijfoodmicro.2019.108492. Epub 2019 Dec 26.

Authors

Danlei Liu¹, Zilei Zhang¹, Ningbo Liao², Songyan Zou², Haoxuan Tang³, Peng Tian⁴, Glenn M Young⁵, Qingping Wu⁶, Dapeng Wang⁷

Affiliations

¹ Department of Food Science and Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China; State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou 510070, China.
² Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310000, China.
³ Department of Food Science and Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
⁴ Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service-United States Department of Agriculture, Albany, CA 94706, USA.
⁵ Department of Food Science and Technology, University of California, Davis, CA 95616, USA.
⁶ Department of Food Science and Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China; State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou 510070, China. Electronic address: wuqp203@163.com.
⁷ Department of Food Science and Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China. Electronic address: dapengwang@sjtu.edu.cn.

PMID: 31896043
DOI: 10.1016/j.ijfoodmicro.2019.108492

Abstract

Human noroviruses (HuNoVs) are the primary non-bacterial pathogens causing acute gastroenteritis worldwide. Attachment and invasion of HuNoVs are thought to involve histo-blood group antigens (HBGAs). Romaine lettuce, which is usually consumed raw, is a common food-related vehicle for HuNoVs transmission. This study investigated the possibility that bacteria resident on the surface of lettuce leaves contribute to norovirus adherence to this food. To test this hypothesis, bacteria were isolated from romaine lettuce and screened to evaluate whether they produced any polysaccharides with structures resembling HBGAs. Twenty-seven bacterial isolates were screened and 18, belonging to 13 different genera, were found to produce HBGAs-like polysaccharides that were recognized by monoclonal antibodies specific to type A, B, H and Lewis a, b, x and y. One bacterial isolate, belonging to the genus Pseudomonas was further investigated because it produced polysaccharides with the widest range of HBGA types, including type B, H and Lewis a, b and x. The Pseudomonas HBGAs-like polysaccharides were found to be extracellular and their production was enhanced when the bacteria were cultured in oligotrophic medium. HuNoVs capture assays revealed that GI.1, GI.8, and GII.2, GII.3, GII.4, GII.6, GII.12, GII.17 genotypes can be bind to Pseudomonas HBGAs-like polysaccharides. The direct evidence of bacterial production HBGAs-like polysaccharides demonstrates one possible mechanism driving accumulation of HuNoVs on lettuce.

Keywords: Bacteria; Extracellular polymeric substances; Histo-blood group antigens; Human norovirus; Lettuce.

MeSH terms

Caliciviridae Infections / transmission*
Caliciviridae Infections / virology
Gastroenteritis / virology*
Genotype
Humans
Lactuca / microbiology*
Lactuca / virology*
Norovirus / classification
Norovirus / isolation & purification*
Polysaccharides, Bacterial / metabolism
Pseudomonas / metabolism*

Substances

Polysaccharides, Bacterial