Yu-Tzu Lin , Ngoc-Niem Bui , Yu-Syuan Cheng , Cheng-Wen Lin , Chun-Li Lee , Tai-Fen Lee , Po-Ren Hsueh
{"title":"金黄色葡萄球菌 t1081/ST45 的高溶血活性是由于 hla 蛋白生成增加和潜在的 RNAIII 非依赖性调控所致。","authors":"Yu-Tzu Lin , Ngoc-Niem Bui , Yu-Syuan Cheng , Cheng-Wen Lin , Chun-Li Lee , Tai-Fen Lee , Po-Ren Hsueh","doi":"10.1016/j.jmii.2024.09.005","DOIUrl":null,"url":null,"abstract":"<div><h3>Background</h3><div>α-Hemolysin, encoded by <em>hla</em>, is a major virulence factor of <em>Staphylococcus aureus</em>. Sequence type (ST) 45 is a globally spread clone with increasing clinical prevalence in Taiwan. Our previous study showed that among the CC45 isolates, the <em>spa</em> type t1081 isolates presented greater hemolytic activity.</div></div><div><h3>Materials and methods</h3><div>The hemolytic activity of 67 CC45 isolates (44 t1081 and 23 non-t1081) from clinical blood cultures was assessed using rabbit red blood cells. The sequences of <em>hla</em> and its upstream regulatory regions and RNAIII were compared between the two groups. The expression of <em>hla</em> and its regulators RNAIII, <em>mgrA</em>, and <em>saeR</em> was analyzed via qRT‒PCR, while Hla protein levels were measured via Western blotting.</div></div><div><h3>Results</h3><div>Compared with non-t1081 isolates, t1081 isolates presented increased hemolytic activity. No significant differences in <em>hla</em> sequences, upstream regulatory regions, or gene expression levels were detected between the two groups. The expression of the transcriptional regulators <em>mgrA</em> and <em>saeR</em> was also similar between the two groups. Western blotting revealed increased Hla protein in the t1081 isolates. However, neither the sequence or expression of RNAIII, a regulator of <em>hla</em> at both the transcriptional and posttranscriptional levels, differed between the groups.</div></div><div><h3>Conclusion</h3><div>Our study revealed that, compared with other CC45 isolates, the t1081/ST45 isolates presented greater hemolytic activity. This heightened activity was due mainly to increased Hla protein levels. Moreover, the higher translation levels may be independent of the known regulator RNAIII, indicating a potential RNAIII-independent mechanism for Hla regulation.</div></div>","PeriodicalId":56117,"journal":{"name":"Journal of Microbiology Immunology and Infection","volume":"58 1","pages":"Pages 70-76"},"PeriodicalIF":4.5000,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"High hemolytic activity in Staphylococcus aureus t1081/ST45 due to increased hla protein production and potential RNAIII-independent regulation\",\"authors\":\"Yu-Tzu Lin , Ngoc-Niem Bui , Yu-Syuan Cheng , Cheng-Wen Lin , Chun-Li Lee , Tai-Fen Lee , Po-Ren Hsueh\",\"doi\":\"10.1016/j.jmii.2024.09.005\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><h3>Background</h3><div>α-Hemolysin, encoded by <em>hla</em>, is a major virulence factor of <em>Staphylococcus aureus</em>. Sequence type (ST) 45 is a globally spread clone with increasing clinical prevalence in Taiwan. Our previous study showed that among the CC45 isolates, the <em>spa</em> type t1081 isolates presented greater hemolytic activity.</div></div><div><h3>Materials and methods</h3><div>The hemolytic activity of 67 CC45 isolates (44 t1081 and 23 non-t1081) from clinical blood cultures was assessed using rabbit red blood cells. The sequences of <em>hla</em> and its upstream regulatory regions and RNAIII were compared between the two groups. The expression of <em>hla</em> and its regulators RNAIII, <em>mgrA</em>, and <em>saeR</em> was analyzed via qRT‒PCR, while Hla protein levels were measured via Western blotting.</div></div><div><h3>Results</h3><div>Compared with non-t1081 isolates, t1081 isolates presented increased hemolytic activity. No significant differences in <em>hla</em> sequences, upstream regulatory regions, or gene expression levels were detected between the two groups. The expression of the transcriptional regulators <em>mgrA</em> and <em>saeR</em> was also similar between the two groups. Western blotting revealed increased Hla protein in the t1081 isolates. However, neither the sequence or expression of RNAIII, a regulator of <em>hla</em> at both the transcriptional and posttranscriptional levels, differed between the groups.</div></div><div><h3>Conclusion</h3><div>Our study revealed that, compared with other CC45 isolates, the t1081/ST45 isolates presented greater hemolytic activity. This heightened activity was due mainly to increased Hla protein levels. Moreover, the higher translation levels may be independent of the known regulator RNAIII, indicating a potential RNAIII-independent mechanism for Hla regulation.</div></div>\",\"PeriodicalId\":56117,\"journal\":{\"name\":\"Journal of Microbiology Immunology and Infection\",\"volume\":\"58 1\",\"pages\":\"Pages 70-76\"},\"PeriodicalIF\":4.5000,\"publicationDate\":\"2025-02-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Microbiology Immunology and Infection\",\"FirstCategoryId\":\"3\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S168411822400183X\",\"RegionNum\":2,\"RegionCategory\":\"医学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"IMMUNOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Microbiology Immunology and Infection","FirstCategoryId":"3","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S168411822400183X","RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"IMMUNOLOGY","Score":null,"Total":0}
High hemolytic activity in Staphylococcus aureus t1081/ST45 due to increased hla protein production and potential RNAIII-independent regulation
Background
α-Hemolysin, encoded by hla, is a major virulence factor of Staphylococcus aureus. Sequence type (ST) 45 is a globally spread clone with increasing clinical prevalence in Taiwan. Our previous study showed that among the CC45 isolates, the spa type t1081 isolates presented greater hemolytic activity.
Materials and methods
The hemolytic activity of 67 CC45 isolates (44 t1081 and 23 non-t1081) from clinical blood cultures was assessed using rabbit red blood cells. The sequences of hla and its upstream regulatory regions and RNAIII were compared between the two groups. The expression of hla and its regulators RNAIII, mgrA, and saeR was analyzed via qRT‒PCR, while Hla protein levels were measured via Western blotting.
Results
Compared with non-t1081 isolates, t1081 isolates presented increased hemolytic activity. No significant differences in hla sequences, upstream regulatory regions, or gene expression levels were detected between the two groups. The expression of the transcriptional regulators mgrA and saeR was also similar between the two groups. Western blotting revealed increased Hla protein in the t1081 isolates. However, neither the sequence or expression of RNAIII, a regulator of hla at both the transcriptional and posttranscriptional levels, differed between the groups.
Conclusion
Our study revealed that, compared with other CC45 isolates, the t1081/ST45 isolates presented greater hemolytic activity. This heightened activity was due mainly to increased Hla protein levels. Moreover, the higher translation levels may be independent of the known regulator RNAIII, indicating a potential RNAIII-independent mechanism for Hla regulation.
期刊介绍:
Journal of Microbiology Immunology and Infection is an open access journal, committed to disseminating information on the latest trends and advances in microbiology, immunology, infectious diseases and parasitology. Article types considered include perspectives, review articles, original articles, brief reports and correspondence.
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