{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,10]],"date-time":"2026-10-10T15:28:15Z","timestamp":1791646095057,"version":"4.3.4"},"reference-count":43,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2025,8,25]],"date-time":"2025-08-25T00:00:00Z","timestamp":1756080000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Intergovernmental International Science and Technology innovation cooperation key project of National Key R&amp;D Program of China","award":["2024YFE0102600"],"award-info":[{"award-number":["2024YFE0102600"]}]},{"name":"Intergovernmental International Science and Technology innovation cooperation key project of National Key R&amp;D Program of China","award":["GWVI-4"],"award-info":[{"award-number":["GWVI-4"]}]},{"name":"Three-Year Initiative Plan for Strengthening Public Health System Construction in Shanghai","award":["2024YFE0102600"],"award-info":[{"award-number":["2024YFE0102600"]}]},{"name":"Three-Year Initiative Plan for Strengthening Public Health System Construction in Shanghai","award":["GWVI-4"],"award-info":[{"award-number":["GWVI-4"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Foods"],"abstract":"<jats:p>Listeria monocytogenes is a Gram-positive bacterial species that causes listeriosis, a major foodborne disease worldwide. The virulence factor inlA facilitates the invasion of L. monocytogenes into intestinal epithelial cells expressing E-cadherin receptors. Naturally occurring premature stop codon (PMSC) mutations in inlA have been shown to result in the production of truncated proteins associated with attenuated virulence. Moreover, different L. monocytogenes strains contain distinct inlA variants. In this study, we first characterized inlA in 546 L. monocytogenes strains isolated from various foods in Shanghai. The results showed that 36.1% (95% Confidence Interval: 32.0~40.2%) of the food isolates harbored inlA with PMSC, which was found to be associated with clonal complex (CC) types, with the highest proportions observed in CC9 and CC121. To investigate the function of inlA, we first used the dominant CC87 isolated from patients as the test strain and constructed an inlA-deleted strain via homologous recombination. Resistance tests and virulence tests showed that while inlA did not affect the resistance of L. monocytogenes, it significantly influenced cell adhesion and invasiveness. To further explore the function of inlA, we performed virulence tests on five CC-type strains carrying inlA with PMSC and their corresponding strains with intact inlA. We found that the virulence of L. monocytogenes strains carrying inlA or inlA with PMSC was associated with their CC type. Our preliminary results showed that premature termination of inlA did not significantly affect the adhesion and invasion abilities of low-virulence CC-type L. monocytogenes strains in Caco-2 cells, but substantially promoted those of high-virulence strains such as CC8 and CC7. In summary, this study preliminarily evaluated the effects of inlA integrity and PMSC mutation variation on the virulence of L. monocytogenes, providing a foundation for further research on inlA-related pathogenic mechanisms.<\/jats:p>","DOI":"10.3390\/foods14172955","type":"journal-article","created":{"date-parts":[[2025,8,25]],"date-time":"2025-08-25T08:26:38Z","timestamp":1756110398000},"page":"2955","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Research on the Genetic Polymorphism and Function of inlA with Premature Stop Codons in Listeria monocytogenes"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9341-6029","authenticated-orcid":false,"given":"Xin","family":"Liu","sequence":"first","affiliation":[{"name":"School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-2812-5526","authenticated-orcid":false,"given":"Binru","family":"Gao","sequence":"additional","affiliation":[{"name":"School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4895-3241","authenticated-orcid":false,"given":"Zhuosi","family":"Li","sequence":"additional","affiliation":[{"name":"School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yingying","family":"Liang","sequence":"additional","affiliation":[{"name":"Shanghai Municipal Center for Disease Control and Prevention, Shanghai 200336, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tianqi","family":"Shi","sequence":"additional","affiliation":[{"name":"Shanghai Municipal Center for Disease Control and Prevention, Shanghai 200336, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9019-0001","authenticated-orcid":false,"given":"Qingli","family":"Dong","sequence":"additional","affiliation":[{"name":"School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Min","family":"Chen","sequence":"additional","affiliation":[{"name":"Shanghai Municipal Center for Disease Control and Prevention, Shanghai 200336, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Huanyu","family":"Wu","sequence":"additional","affiliation":[{"name":"Shanghai Municipal Center for Disease Control and Prevention, Shanghai 200336, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hongzhi","family":"Zhang","sequence":"additional","affiliation":[{"name":"Shanghai Municipal Center for Disease Control and Prevention, Shanghai 200336, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,8,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Ji, S., Song, Z., Luo, L., Wang, Y., Li, L., Mao, P., Ye, C., and Wang, Y. (2023). Whole-genome sequencing reveals genomic characterization of Listeria monocytogenes from food in China. Front. Microbiol., 13.","DOI":"10.3389\/fmicb.2022.1049843"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"944","DOI":"10.1056\/NEJMoa1215837","article-title":"Multistate outbreak of listeriosis associated with cantaloupe","volume":"369","author":"McCollum","year":"2013","journal-title":"N. Engl. J. Med."},{"key":"ref_3","unstructured":"(2023, December 14). CDC (Centers for Disease Control and Prevention), 2023. Listeria (Listeriosis), Available online: https:\/\/www.cdc.gov\/listeria\/index.html."},{"key":"ref_4","unstructured":"(2024). The European Union One Health 2023 Zoonoses report. EFSA J., 22, 544."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1248","DOI":"10.1111\/tmi.12173","article-title":"Systematic review of human listeriosis in China, 1964\u20132010","volume":"18","author":"Feng","year":"2013","journal-title":"Trop. Med. Int. Health"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1016\/j.ijid.2019.01.007","article-title":"Listeriosis in mainland China: A systematic review","volume":"81","author":"Fan","year":"2019","journal-title":"Int. J. Infect. Dis."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"2307520","DOI":"10.1080\/22221751.2024.2307520","article-title":"Risk factors associated with food consumption and food-handling habits for sporadic listeriosis: A case-control study in China from 2013 to 2022","volume":"13","author":"Niu","year":"2024","journal-title":"Emerg. Microbes Infect."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1407","DOI":"10.1111\/mmi.14836","article-title":"Role of internalin proteins in the pathogenesis of Listeria monocytogenes","volume":"116","author":"Ireton","year":"2021","journal-title":"Mol. Microbiol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"3215","DOI":"10.1099\/mic.0.28070-0","article-title":"\u03c3 B contributes to Listeria monocytogenes invasion by controlling expression of inlA and inlB","volume":"151","author":"Kim","year":"2005","journal-title":"Microbiology"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Phelps, C.C., Vadia, S., Arnett, E., Tan, Y., Zhang, X., Pathak-Sharma, S., Gavrilin, M.A., and Seveau, S. (2018). Relative roles of Listeriolysin O, InlA, and InlB in Listeria monocytogenes uptake by host cells. Infect Immun., 86.","DOI":"10.1128\/IAI.00555-18"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Li, L., Wang, Y., Pu, J., Chen, J., Liu, L., Mao, P., Sun, H., Luo, X., and Ye, C. (2024). Unveiling the mutations and conservation of InlA in Listeria monocytogenes. Microorganisms, 12.","DOI":"10.3390\/microorganisms12030485"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"30","DOI":"10.1186\/s13099-019-0307-8","article-title":"Characterization of internalin genes in Listeria monocytogenes from food and humans, and their association with the invasion of Caco-2 cells","volume":"11","author":"Su","year":"2019","journal-title":"Gut Pathog."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2479","DOI":"10.1128\/AEM.02626-10","article-title":"Significant shift in median guinea pig infectious dose shown by an outbreak-associated Listeria monocytogenes epidemic clone strain and a strain carrying a premature stop codon mutation in inlA","volume":"77","author":"Simpson","year":"2011","journal-title":"Appl. Environ. Microbiol."},{"key":"ref_14","first-page":"293","article-title":"A novel mutation leading to a premature stop codon in inlA of Listeria monocytogenes isolated from neonatal listeriosis","volume":"38","year":"2015","journal-title":"New Microbiol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1799","DOI":"10.1099\/jmm.0.057505-0","article-title":"Listeria monocytogenes strains encoding premature stop codons in inlA invade mice and guinea pig fetuses in orally dosed dams","volume":"62","author":"Holch","year":"2013","journal-title":"J. Med. Microbiol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"243","DOI":"10.1089\/fpd.2020.2855","article-title":"Assessment of internalin a gene sequences and cell adhesion and invasion capacity of Listeria monocytogenes strains isolated from foods of animal and related origins","volume":"18","author":"Medeiros","year":"2021","journal-title":"Foodborne Pathog. Dis."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Magagna, G., Gori, M., Russini, V., De Angelis, V., Spinelli, E., Filipello, V., Tranquillo, V.M., De Marchis, M.L., Boss\u00f9, T., and Fappani, C. (2023). Evaluation of the virulence potential of Listeria monocytogenes through the characterization of the truncated forms of internalin A. Int. J. Mol. Sci., 24.","DOI":"10.3390\/ijms241210141"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"2783","DOI":"10.1128\/AEM.02651-09","article-title":"Revelation by single-nucleotide polymorphism genotyping that mutations leading to a premature stop codon in inlA are common among Listeria monocytogenes isolates from ready-to-eat foods but not human listeriosis cases","volume":"76","author":"Simpson","year":"2010","journal-title":"Appl. Environ. Microbiol."},{"key":"ref_19","unstructured":"(2016). National Food Safety Standard-Food Microbiology Inspection Listeria monocytogenes Inspection (Standard No. GB4789.30-2016)."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Wassinger, A., Zhang, L., Tracy, E., Munson, R.S., Jr Kathariou, S., and Wang, H.H. (2013). Role of a GntR-family response regulator LbrA in Listeria monocytogenes biofilm formation. PLoS ONE, 8.","DOI":"10.1371\/journal.pone.0070448"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Liu, X., Chen, W., Fang, Z., Yu, Y., Bi, J., Wang, J., Dong, Q., and Zhang, H. (2022). Persistence of Listeria monocytogenes ST5 in ready-to-eat food processing environment. Foods, 11.","DOI":"10.3390\/foods11172561"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"115114","DOI":"10.1016\/j.lwt.2023.115114","article-title":"Growth and survival characteristics of Listeria monocytogenes of different sources and subtypes","volume":"184","author":"Cheng","year":"2023","journal-title":"Lwt"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Dong, Q., Lu, X., Gao, B., Liu, Y., Aslam, M.Z., Wang, X., and Li, Z. (2022). Lactiplantibacillus plantarum subsp. plantarum and fructooligosaccharides combination inhibits the growth, adhesion, invasion, and virulence of Listeria monocytogenes. Foods, 11.","DOI":"10.3390\/foods11020170"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"fyac021","DOI":"10.1093\/fqsafe\/fyac021","article-title":"Systematic review of Listeria monocytogenes from food and clinical samples in Chinese mainland from 2010 to 2019","volume":"6","author":"Cheng","year":"2022","journal-title":"Food Qual. Saf."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"114232","DOI":"10.1016\/j.foodres.2024.114232","article-title":"Growth, biofilm formation, and motility of Listeria monocytogenes strains isolated from food and clinical samples located in Shanghai (China)","volume":"184","author":"Gao","year":"2024","journal-title":"Food Res. Int."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Liu, X., Shi, T., Li, J., Wu, H., Zhao, Q., Fang, Z., Liang, Y., Xiao, Q., Chen, M., and Dong, Q. (2025). pLM33 provides tolerance of persistent Listeria monocytogenes ST5 to various stress conditions and also enhances its virulence. Food Microbiol., 126.","DOI":"10.1016\/j.fm.2024.104675"},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Shi, Q., Zhang, X., Wang, D., Zhang, W., Jin, X., Sun, Y., and Huang, A. (2025). Genetic diversity, antimicrobial resistance, and virulence profiles of Listeria monocytogenes isolates from Nantong, China (2020\u20132023). Foodborne Pathog. Dis.","DOI":"10.1089\/fpd.2025.0027"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Zhang, H., Chen, W., Wang, J., Xu, B., Liu, H., Dong, Q., and Zhang, X. (2020). 10-Year molecular surveillance of Listeria monocytogenes using whole-genome sequencing in Shanghai, China, 2009\u20132019. Front. Microbiol., 11.","DOI":"10.3389\/fmicb.2020.551020"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"6","DOI":"10.1016\/j.fm.2016.10.033","article-title":"Detection of premature stop codons leading to truncated internalin A among food and clinical strains of Listeria monocytogenes","volume":"63","author":"Ferreira","year":"2017","journal-title":"Food Microbiol."},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Hingston, P., Chen, J., Dhillon, B.K., Laing, C., Bertelli, C., Gannon, V., Tasara, T., Allen, K., Brinkman, F.S.L., and Hansen, L.T. (2017). Genotypes associated with Listeria monocytogenes isolates displaying impaired or enhanced tolerances to cold, salt, acid, or desiccation stress. Front. Microbiol., 8.","DOI":"10.3389\/fmicb.2017.00369"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"114067","DOI":"10.1016\/j.foodres.2024.114067","article-title":"Recent advances on the formation, detection, resistance mechanism, and control technology of Listeria monocytogenes biofilm in food industry","volume":"180","author":"Liu","year":"2024","journal-title":"Food Res Int."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"372","DOI":"10.1007\/s00284-013-0377-7","article-title":"PrfA led to reduced biofilm formation and contributed to altered gene expression patterns in biofilm-forming Listeria monocytogenes","volume":"67","author":"Luo","year":"2013","journal-title":"Curr. Microbiol."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Di Ciccio, P., Rubiola, S., Panebianco, F., Lomonaco, S., Allard, M., Bianchi, D.M., Civera, T., and Chiesa, F. (2022). Biofilm formation and genomic features of Listeria monocytogenes strains isolated from meat and dairy industries located in Piedmont (Italy). Int. J. Food Microbiol., 378.","DOI":"10.1016\/j.ijfoodmicro.2022.109784"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"183","DOI":"10.1177\/039463200902200121","article-title":"Expression of internalin A and biofilm formation among Listeria monocytogenes clinical isolates","volume":"22","author":"Franciosa","year":"2009","journal-title":"Int. J. Immunopathol. Pharmacol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1038\/s41522-021-00189-5","article-title":"Biofilm-isolated Listeria monocytogenes exhibits reduced systemic dissemination at the early (12\u201324\u2009h) stage of infection in a mouse model","volume":"7","author":"Bai","year":"2021","journal-title":"npj Biofilms Microbiomes"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"89","DOI":"10.4315\/0362-028X.JFP-19-210","article-title":"In vitro gene transcription of Listeria monocytogenes after exposure to human gastric and duodenal aspirates","volume":"83","author":"Hadjilouka","year":"2020","journal-title":"J. Food Prot."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Wu, S., Wu, Q., Zhang, J., Chen, M., and Guo, W. (2016). Analysis of multilocus sequence typing and virulence characterization of Listeria monocytogenes isolates from Chinese retail ready-to-eat Food. Front. Microbiol., 7.","DOI":"10.3389\/fmicb.2016.00168"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"2094","DOI":"10.1086\/420853","article-title":"A molecular marker for evaluating the pathogenic potential of foodborne Listeria monocytogenes","volume":"189","author":"Jacquet","year":"2004","journal-title":"J. Infect. Dis."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"7365","DOI":"10.1128\/AEM.01138-08","article-title":"Development and implementation of a multiplex single-nucleotide polymorphism genotyping assay for detection of virulence-attenuating mutations in the Listeria monocytogenes virulence-associated gene inlA","volume":"74","author":"Nightingale","year":"2008","journal-title":"Appl. Environ. Microbiol."},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Pouillot, R., Kiermeier, A., Guillier, L., Cadavez, V., and Sanaa, M. (2024). Updated parameters for Listeria monocytogenes dose\u2013response model considering pathogen virulence and age and sex of consumer. Foods, 13.","DOI":"10.3390\/foods13050751"},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Dellafiora, L., Filipello, V., Dall\u2019Asta, C., Finazzi, G., Galaverna, G., and Losio, M.N. (2020). A structural study on the Listeria monocytogenes internalin A\u2014Human E-cadherin interaction: A molecular tool to investigate the effects of missense mutations. Toxins, 12.","DOI":"10.3390\/toxins12010060"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1733","DOI":"10.4315\/0362-028X.JFP-16-145","article-title":"Listeria monocytogenes isolates carrying virulence-attenuating mutations in internalin A are Commonly isolated from ready-to-eat food processing plant and retail environments","volume":"79","author":"Roberts","year":"2016","journal-title":"J. Food Prot."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"379","DOI":"10.4161\/viru.2.5.17703","article-title":"The arsenal of virulence factors deployed by Listeria monocytogenes to promote its cell infection cycle","volume":"2","author":"Camejo","year":"2011","journal-title":"Virulence"}],"container-title":["Foods"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2304-8158\/14\/17\/2955\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T18:35:35Z","timestamp":1760034935000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2304-8158\/14\/17\/2955"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,8,25]]},"references-count":43,"journal-issue":{"issue":"17","published-online":{"date-parts":[[2025,9]]}},"alternative-id":["foods14172955"],"URL":"https:\/\/doi.org\/10.3390\/foods14172955","relation":{},"ISSN":["2304-8158"],"issn-type":[{"value":"2304-8158","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,8,25]]}}}