Background: Cigarette smoking remains a leading cause of mortality worldwide. Streptococcus pneumoniae, also known as pneumococcus, is one of the most common pathogens that colonizes the human respiratory tract, causing life-threatening infections. Several studies have reported that cigarette smoke (CS) exposure promotes pneumococcal infectivity; however, the underlying mechanisms remain to be illustrated.
Methods: In this study, we prepared cigarette smoke extract (CSE) from tobacco containing nicotine (0.8 mg/cigarette) and tar (10 mg/cigarette) to investigate the effects of CSE on innate immune response using murine macrophage models.
Results: The results from the cytokine array showed that the production of C-C Motif Chemokine Ligand 2 (CCL2), CCL4, CCL3, C-X-C Motif Chemokine Ligand 2 (CXCL2), and CXCL-10, in pneumococcus-infected cells was reduced upon 5 % CSE treatment. Our results further demonstrated that 5 % CSE exposure, followed by pneumococcal challenge, significantly decreased CCL2 and type I interferon (IFN) production in macrophages by inhibiting nuclear factor (NF)-κB and IFN regulatory factor 3 (IRF3) signaling pathways. Moreover, CSE disrupts macrophage polarization and impedes innate immune signaling to suppress pneumococcal phagocytosis by macrophages.
Conclusion: Our results provide evidence that CS manipulates the signaling molecules to subvert macrophage functions, thereby hindering the innate response against pneumococcal infection.
{"title":"Cigarette smoke compromises macrophage innate sensing in response to pneumococcal infection.","authors":"Wei-Chih Liao, Chia-Huei Chou, Mao-Wang Ho, Jo-Tsen Chen, Shu-Ling Chou, Yu-Tsen Huang, Ngoc-Niem Bui, Hui-Yu Wu, Chi-Fan Lee, Wei-Chien Huang, Chih-Ho Lai","doi":"10.1016/j.jmii.2024.10.001","DOIUrl":"https://doi.org/10.1016/j.jmii.2024.10.001","url":null,"abstract":"<p><strong>Background: </strong>Cigarette smoking remains a leading cause of mortality worldwide. Streptococcus pneumoniae, also known as pneumococcus, is one of the most common pathogens that colonizes the human respiratory tract, causing life-threatening infections. Several studies have reported that cigarette smoke (CS) exposure promotes pneumococcal infectivity; however, the underlying mechanisms remain to be illustrated.</p><p><strong>Methods: </strong>In this study, we prepared cigarette smoke extract (CSE) from tobacco containing nicotine (0.8 mg/cigarette) and tar (10 mg/cigarette) to investigate the effects of CSE on innate immune response using murine macrophage models.</p><p><strong>Results: </strong>The results from the cytokine array showed that the production of C-C Motif Chemokine Ligand 2 (CCL2), CCL4, CCL3, C-X-C Motif Chemokine Ligand 2 (CXCL2), and CXCL-10, in pneumococcus-infected cells was reduced upon 5 % CSE treatment. Our results further demonstrated that 5 % CSE exposure, followed by pneumococcal challenge, significantly decreased CCL2 and type I interferon (IFN) production in macrophages by inhibiting nuclear factor (NF)-κB and IFN regulatory factor 3 (IRF3) signaling pathways. Moreover, CSE disrupts macrophage polarization and impedes innate immune signaling to suppress pneumococcal phagocytosis by macrophages.</p><p><strong>Conclusion: </strong>Our results provide evidence that CS manipulates the signaling molecules to subvert macrophage functions, thereby hindering the innate response against pneumococcal infection.</p>","PeriodicalId":56117,"journal":{"name":"Journal of Microbiology Immunology and Infection","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142549192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-24DOI: 10.1016/j.jmii.2024.10.002
Tien-Huang Lin, Chen-Yu Wang, Chien-Chen Wu, Ching-Ting Lin
Background: Klebsiella pneumoniae is a Gram-negative bacterium that can cause infections, especially in individuals with diabetes. Recently, more hypervirulent strains have emerged, posing a threat even to healthy individuals. Understanding how K. pneumoniae regulates its virulence factors is crucial. Acetyl-phosphate (AcP) is essential for bacterial metabolism and can affect virulence factor expression. However, the role of the Pta-AckA pathway, which regulates AcP levels, in K. pneumoniae pathogenesis remains unclear.
Methods: Deletion mutants lacking the pta and ackA, involved in AcP production and hydrolysis, were generated in K. pneumoniae CG43S3. Their effects on AcP levels, the patterns of global acetylated protein, capsular polysaccharide (CPS) amount, serum resistance, type 3 fimbriae expression, biofilm formation, and virulence in G. mellonella larva were assessed.
Results: Deletion of ackA in K. pneumoniae CG43S3 led to AcP accumulation, while pta deletion abolished AcP synthesis when grown in TB7+1 % glucose. This pathway influenced global protein acetylation, with pta deletion decreasing acetylation and ackA deletion increasing it. Additionally, pta deletion decreased the CPS amount, serum resistance, and type 3 fimbriae expression, while ackA deletion increased these factors. Furthermore, deleting pta and ackA attenuated the infected larva's virulence and death rate.
Conclusion: Our findings highlight the critical role of the Pta-AckA pathway in K. pneumoniae pathogenesis. This pathway regulates AcP levels, global protein acetylation, CPS production, serum resistance, and type 3 fimbriae expression, ultimately impacting virulence. The information provides insights into potential therapeutic targets for combating K. pneumoniae infection.
{"title":"Impacts of Pta-AckA pathway on CPS biosynthesis and type 3 fimbriae expression in Klebsiella pneumoniae.","authors":"Tien-Huang Lin, Chen-Yu Wang, Chien-Chen Wu, Ching-Ting Lin","doi":"10.1016/j.jmii.2024.10.002","DOIUrl":"https://doi.org/10.1016/j.jmii.2024.10.002","url":null,"abstract":"<p><strong>Background: </strong>Klebsiella pneumoniae is a Gram-negative bacterium that can cause infections, especially in individuals with diabetes. Recently, more hypervirulent strains have emerged, posing a threat even to healthy individuals. Understanding how K. pneumoniae regulates its virulence factors is crucial. Acetyl-phosphate (AcP) is essential for bacterial metabolism and can affect virulence factor expression. However, the role of the Pta-AckA pathway, which regulates AcP levels, in K. pneumoniae pathogenesis remains unclear.</p><p><strong>Methods: </strong>Deletion mutants lacking the pta and ackA, involved in AcP production and hydrolysis, were generated in K. pneumoniae CG43S3. Their effects on AcP levels, the patterns of global acetylated protein, capsular polysaccharide (CPS) amount, serum resistance, type 3 fimbriae expression, biofilm formation, and virulence in G. mellonella larva were assessed.</p><p><strong>Results: </strong>Deletion of ackA in K. pneumoniae CG43S3 led to AcP accumulation, while pta deletion abolished AcP synthesis when grown in TB7+1 % glucose. This pathway influenced global protein acetylation, with pta deletion decreasing acetylation and ackA deletion increasing it. Additionally, pta deletion decreased the CPS amount, serum resistance, and type 3 fimbriae expression, while ackA deletion increased these factors. Furthermore, deleting pta and ackA attenuated the infected larva's virulence and death rate.</p><p><strong>Conclusion: </strong>Our findings highlight the critical role of the Pta-AckA pathway in K. pneumoniae pathogenesis. This pathway regulates AcP levels, global protein acetylation, CPS production, serum resistance, and type 3 fimbriae expression, ultimately impacting virulence. The information provides insights into potential therapeutic targets for combating K. pneumoniae infection.</p>","PeriodicalId":56117,"journal":{"name":"Journal of Microbiology Immunology and Infection","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142549193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Serum Mpox-specific IgG titers before and after breakthrough Mpox infection in an HIV-infected individual with viral suppression and prior 2-dose Mpox vaccination.","authors":"Wang-Da Liu, Tai-Ling Chao, Sui-Yuan Chang, Chien-Ching Hung","doi":"10.1016/j.jmii.2024.10.003","DOIUrl":"https://doi.org/10.1016/j.jmii.2024.10.003","url":null,"abstract":"","PeriodicalId":56117,"journal":{"name":"Journal of Microbiology Immunology and Infection","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142549194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Background: The inflammatory bowel disease (IBD), comprising Crohn's disease (CD) and ulcerative colitis (UC) is a complex disease with multifactorial etiology. The intestinal dysbiosis have been investigated to play an important role in IBD pathogenesis and disease activity. The aim of our study was to analyze the intestinal microbiota composition in IBD across different severity levels and the impact of biologic therapy on microbiota modulation.
Methods: In this study, 27 IBD patients were recruited, including 14 patients undergoing biologic therapy for moderate to severe disease activity and 13 controls with inactive disease. The gut microbial composition was determined by 16 S ribosomal RNA gene sequencing of stool samples.
Results: Biologic therapy led to significant clinical improvement in IBD disease activity after 48 weeks. About species richness, community alpha diversity was significant lower in active CD patients and enriched gradually after biologic therapy. The beta-diversity regard to the difference of bacterial community composition showed significant difference between patients in biologic and control group. A decrease in Firmicutes and increase in Bacteroidetes abundance were observed in patients with active disease, both in CD and UC. Biologic treatment induced shifts in gut microbiota, with increased Firmicutes and decreased Bacteroidetes, as well as improved F/B ratio gradually after treatment, correlating with disease activity.
Conclusions: Our study suggested that gut microbiota differences changed after biologic therapies among IBD with different disease activity, and a rising Firmicutes/Bacteroidetes ratio could be a potential predictor for disease activity and treatment response monitoring.
背景:炎症性肠病(IBD),包括克罗恩病(CD)和溃疡性结肠炎(UC),是一种病因复杂的多因素疾病。据研究,肠道菌群失调在 IBD 发病机制和疾病活动中发挥着重要作用。我们的研究旨在分析不同严重程度的IBD患者的肠道微生物群组成,以及生物治疗对微生物群调节的影响:本研究共招募了 27 名 IBD 患者,包括 14 名因中重度疾病活动而接受生物治疗的患者和 13 名疾病不活跃的对照组患者。通过对粪便样本进行16 S核糖体RNA基因测序,确定肠道微生物组成:结果:48周后,生物疗法明显改善了IBD疾病的临床活动。在物种丰富度方面,活动性 CD 患者的群落α多样性明显较低,生物治疗后逐渐丰富。关于细菌群落组成差异的贝塔多样性显示,生物治疗组和对照组患者之间存在显著差异。在活动性疾病患者中,无论是 CD 还是 UC,都观察到了固醇菌的减少和类杆菌的增加。生物制剂治疗诱导肠道微生物群发生变化,固缩菌增加,类杆菌减少,治疗后F/B比值逐渐改善,这与疾病活动相关:我们的研究表明,不同疾病活动性的 IBD 患者在接受生物制剂治疗后肠道微生物群的差异发生了变化,而固缩菌/类杆菌比值的升高可作为疾病活动性和治疗反应监测的潜在预测指标。
{"title":"Alternations of the gut microbiota and the Firmicutes/Bacteroidetes ratio after biologic treatment in inflammatory bowel disease.","authors":"Yu-Chieh Tsai, Wei-Chen Tai, Chih-Ming Liang, Cheng-Kun Wu, Ming-Chao Tsai, Wan-Hsiang Hu, Pao-Yuan Huang, Chien-Hung Chen, Yuan-Hung Kuo, Chih-Chien Yao, Seng-Kee Chuah","doi":"10.1016/j.jmii.2024.09.006","DOIUrl":"https://doi.org/10.1016/j.jmii.2024.09.006","url":null,"abstract":"<p><strong>Background: </strong>The inflammatory bowel disease (IBD), comprising Crohn's disease (CD) and ulcerative colitis (UC) is a complex disease with multifactorial etiology. The intestinal dysbiosis have been investigated to play an important role in IBD pathogenesis and disease activity. The aim of our study was to analyze the intestinal microbiota composition in IBD across different severity levels and the impact of biologic therapy on microbiota modulation.</p><p><strong>Methods: </strong>In this study, 27 IBD patients were recruited, including 14 patients undergoing biologic therapy for moderate to severe disease activity and 13 controls with inactive disease. The gut microbial composition was determined by 16 S ribosomal RNA gene sequencing of stool samples.</p><p><strong>Results: </strong>Biologic therapy led to significant clinical improvement in IBD disease activity after 48 weeks. About species richness, community alpha diversity was significant lower in active CD patients and enriched gradually after biologic therapy. The beta-diversity regard to the difference of bacterial community composition showed significant difference between patients in biologic and control group. A decrease in Firmicutes and increase in Bacteroidetes abundance were observed in patients with active disease, both in CD and UC. Biologic treatment induced shifts in gut microbiota, with increased Firmicutes and decreased Bacteroidetes, as well as improved F/B ratio gradually after treatment, correlating with disease activity.</p><p><strong>Conclusions: </strong>Our study suggested that gut microbiota differences changed after biologic therapies among IBD with different disease activity, and a rising Firmicutes/Bacteroidetes ratio could be a potential predictor for disease activity and treatment response monitoring.</p>","PeriodicalId":56117,"journal":{"name":"Journal of Microbiology Immunology and Infection","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142407279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Background: Hemodialysis patients exhibit a reduced response to vaccination and have different vaccine dose regimens. Vaccines induce antibodies and affect the inflammatory balance through antibody glycosylation and effector functions. Therefore, we aimed to analyze the antibody glycosylation profiles in hemodialysis patients who were vaccinated against severe acute respiratory syndrome coronavirus 2, infected with the virus, or both, and compare them with those of dialysis patients in a control group.
Methods: Plasma samples from 112 hemodialysis patients were assigned to four groups: control, infected, vaccinated, and post-vaccine-infected. Paired plasma samples from 47 people with vaccination (vaccinees) were analyzed before and after the booster dose. The same analytical approach was applied to the four groups for a cross-sectional comparison.
Results: Our study found that both vaccination and infection groups showed decreased fucosylation of IgG1, which is associated with a proinflammatory biosignature. However, vaccination also leads to increased galactosylation and bisection of IgG antibodies, which are associated with anti-inflammatory effects and the additional regulation of immune responses. In contrast, infection led to an additional decrease in the fucosylation of IgG2 and IgA, demonstrating a more intense proinflammatory biosignature than vaccination.
Conclusions: Our findings emphasize the proinflammatory biosignature of afucosylation in both vaccination and infection groups. Additionally, we uncovered further regulated profiles related to galactosylation in vaccinees. These findings suggest that antibody investigation for vaccination or infection should not solely focus on neutralization but should also consider effector function-related glycosylation profiling. This comprehensive information can be valuable for fine-tuning vaccine development in the future.
{"title":"Unveiling unique effector function-related bulk antibody profiles in long-term hemodialysis patients following COVID-19 mRNA booster vaccination.","authors":"Chia-Yi Chou, Chung-Yi Cheng, Chih-Hsin Lee, Makoto Kuro-O, Tso-Hsiao Chen, San-Yuan Wang, Yung-Kun Chuang, Yun-Jung Yang, Yun-Hsuan Lin, I-Lin Tsai","doi":"10.1016/j.jmii.2024.09.007","DOIUrl":"https://doi.org/10.1016/j.jmii.2024.09.007","url":null,"abstract":"<p><strong>Background: </strong>Hemodialysis patients exhibit a reduced response to vaccination and have different vaccine dose regimens. Vaccines induce antibodies and affect the inflammatory balance through antibody glycosylation and effector functions. Therefore, we aimed to analyze the antibody glycosylation profiles in hemodialysis patients who were vaccinated against severe acute respiratory syndrome coronavirus 2, infected with the virus, or both, and compare them with those of dialysis patients in a control group.</p><p><strong>Methods: </strong>Plasma samples from 112 hemodialysis patients were assigned to four groups: control, infected, vaccinated, and post-vaccine-infected. Paired plasma samples from 47 people with vaccination (vaccinees) were analyzed before and after the booster dose. The same analytical approach was applied to the four groups for a cross-sectional comparison.</p><p><strong>Results: </strong>Our study found that both vaccination and infection groups showed decreased fucosylation of IgG1, which is associated with a proinflammatory biosignature. However, vaccination also leads to increased galactosylation and bisection of IgG antibodies, which are associated with anti-inflammatory effects and the additional regulation of immune responses. In contrast, infection led to an additional decrease in the fucosylation of IgG2 and IgA, demonstrating a more intense proinflammatory biosignature than vaccination.</p><p><strong>Conclusions: </strong>Our findings emphasize the proinflammatory biosignature of afucosylation in both vaccination and infection groups. Additionally, we uncovered further regulated profiles related to galactosylation in vaccinees. These findings suggest that antibody investigation for vaccination or infection should not solely focus on neutralization but should also consider effector function-related glycosylation profiling. This comprehensive information can be valuable for fine-tuning vaccine development in the future.</p>","PeriodicalId":56117,"journal":{"name":"Journal of Microbiology Immunology and Infection","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142481864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Background: Tuberculosis (TB) is a major global public health issue. Prompt and accurate TB diagnosis is crucial for starting appropriate treatments and preventing the disease's spread. Current diagnostic techniques are either slow or expensive. This study aimed to create and evaluate a new, fast, highly reliable, and cost-effective TB detection method using a gene chip and Restriction Fragment Length Polymorphism (RFLP) analysis on Mycobacteria Growth Indicator Tubes (MGIT) specimens.
Methods: We assessed the effectiveness of a novel gene chip and RFLP methods targeting the 16S rRNA gene of Mycobacterium tuberculosis in 2000 MGIT culture-positive specimens. RFLP analysis identified the AfeI restriction site within the M. tuberculosis complex (MTBC) genome. Discrepancies were investigated through extensive sequencing and Cobas TaqMan PCR analysis, along with reviewing patient profiles.
Results: Both methods showed high efficacy in detecting MTBC in broth cultures, with the gene chip method achieving a sensitivity of 99.27 %, specificity of 98.35 %, and the RFLP method showing a sensitivity of 98.18 %, specificity of 99.31 %. False negatives in two isolates were due to a mutation in the AfeI site. Additionally, five cases showed MTBC presence when nontuberculous Mycobacterium species grew in cultures.
Conclusion: Our novel gene chip and RFLP methods are effective for rapid highly-reliable and cost-effective M. tuberculosis detection in MGIT specimens. Both gene chip and RFLP methods are suitable for resource-limited settings, offering an economical advantage. These methods have significant potential to improve clinical TB diagnosis.
{"title":"Development of the novel gene chip and restriction fragment length polymorphism (RFLP) methods for rapid detection of Mycobacterium tuberculosis complex in broth culture.","authors":"Wen-Hung Wang, Chun-Yu Lin, Shu-Huei Jain, Po-Liang Lu, Yen-Hsu Chen","doi":"10.1016/j.jmii.2024.09.003","DOIUrl":"https://doi.org/10.1016/j.jmii.2024.09.003","url":null,"abstract":"<p><strong>Background: </strong>Tuberculosis (TB) is a major global public health issue. Prompt and accurate TB diagnosis is crucial for starting appropriate treatments and preventing the disease's spread. Current diagnostic techniques are either slow or expensive. This study aimed to create and evaluate a new, fast, highly reliable, and cost-effective TB detection method using a gene chip and Restriction Fragment Length Polymorphism (RFLP) analysis on Mycobacteria Growth Indicator Tubes (MGIT) specimens.</p><p><strong>Methods: </strong>We assessed the effectiveness of a novel gene chip and RFLP methods targeting the 16S rRNA gene of Mycobacterium tuberculosis in 2000 MGIT culture-positive specimens. RFLP analysis identified the AfeI restriction site within the M. tuberculosis complex (MTBC) genome. Discrepancies were investigated through extensive sequencing and Cobas TaqMan PCR analysis, along with reviewing patient profiles.</p><p><strong>Results: </strong>Both methods showed high efficacy in detecting MTBC in broth cultures, with the gene chip method achieving a sensitivity of 99.27 %, specificity of 98.35 %, and the RFLP method showing a sensitivity of 98.18 %, specificity of 99.31 %. False negatives in two isolates were due to a mutation in the AfeI site. Additionally, five cases showed MTBC presence when nontuberculous Mycobacterium species grew in cultures.</p><p><strong>Conclusion: </strong>Our novel gene chip and RFLP methods are effective for rapid highly-reliable and cost-effective M. tuberculosis detection in MGIT specimens. Both gene chip and RFLP methods are suitable for resource-limited settings, offering an economical advantage. These methods have significant potential to improve clinical TB diagnosis.</p>","PeriodicalId":56117,"journal":{"name":"Journal of Microbiology Immunology and Infection","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142333172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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.
{"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":"https://doi.org/10.1016/j.jmii.2024.09.005","url":null,"abstract":"<p><strong>Background: </strong>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.</p><p><strong>Materials and methods: </strong>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.</p><p><strong>Results: </strong>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.</p><p><strong>Conclusion: </strong>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.</p>","PeriodicalId":56117,"journal":{"name":"Journal of Microbiology Immunology and Infection","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142333173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Background: Nontyphoidal Salmonella (NTS) outbreaks of invasive diseases are increasing. Whether the genetic diversity of invasive NTS correlates with the clinical characteristics and bacteremia development in NTS infections remains unclear. In this study, we compared the global transcriptomes between bacteremic and nonbacteremic NTS strains after their interaction with human intestinal epithelial cells in vitro.
Methods: We selected clinical isolates obtained from stool and blood samples of patients with or without bacteremia and patients with high and low C-reactive protein (CRP) levels. The bacterial RNA samples were isolated after coculturing with Caco-2 cells for RNA sequencing and subsequent analyses.
Results: CRP is an unreliable predictive maker for NTS bacteremia with a median CRP level of 1.6 mg/dL. Certain Salmonella Pathogenicity Island (SPI)-1 genes (sipC, sipA, sicA, sipD, and sipB), SPI-2 genes (ssaP, ssrA, and ssaS), and six SPI-4 genes (siiA, siiB, siiC, siiD, siiE, and siiF) remained upregulated in the bacteremic blood-derived strains but significantly downregulated in the nonbacteremic strains after their interaction with Caco-2 cells. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways analysis identified that arginine biosynthesis, ascorbate and aldarate metabolism, and phosphotransferase system pathways were activated in bacteremic NTS strains after Caco-2 cell priming.
Conclusion: CRP levels were not correlated with bacteremia development. Significant regulation of certain SPI genes in bacteremic NTS strains after Caco-2 cell priming; bacteremia development might be influenced by the host immune response and the extent to which specific metabolism pathways in NTS strains can be prevented from invading the bloodstream.
{"title":"Comparison of global transcriptomes for nontyphoidal Salmonella clinical isolates from pediatric patients with and without bacteremia after their interaction with human intestinal epithelial cells in vitro.","authors":"Buyandelger Batsaikhan, Pei-Chun Lin, Katsumi Shigemura, Yu-Wei Wu, Reo Onishi, Pei-Ru Chang, Hung-Yen Cheng, Shiuh-Bin Fang","doi":"10.1016/j.jmii.2024.09.002","DOIUrl":"https://doi.org/10.1016/j.jmii.2024.09.002","url":null,"abstract":"<p><strong>Background: </strong>Nontyphoidal Salmonella (NTS) outbreaks of invasive diseases are increasing. Whether the genetic diversity of invasive NTS correlates with the clinical characteristics and bacteremia development in NTS infections remains unclear. In this study, we compared the global transcriptomes between bacteremic and nonbacteremic NTS strains after their interaction with human intestinal epithelial cells in vitro.</p><p><strong>Methods: </strong>We selected clinical isolates obtained from stool and blood samples of patients with or without bacteremia and patients with high and low C-reactive protein (CRP) levels. The bacterial RNA samples were isolated after coculturing with Caco-2 cells for RNA sequencing and subsequent analyses.</p><p><strong>Results: </strong>CRP is an unreliable predictive maker for NTS bacteremia with a median CRP level of 1.6 mg/dL. Certain Salmonella Pathogenicity Island (SPI)-1 genes (sipC, sipA, sicA, sipD, and sipB), SPI-2 genes (ssaP, ssrA, and ssaS), and six SPI-4 genes (siiA, siiB, siiC, siiD, siiE, and siiF) remained upregulated in the bacteremic blood-derived strains but significantly downregulated in the nonbacteremic strains after their interaction with Caco-2 cells. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways analysis identified that arginine biosynthesis, ascorbate and aldarate metabolism, and phosphotransferase system pathways were activated in bacteremic NTS strains after Caco-2 cell priming.</p><p><strong>Conclusion: </strong>CRP levels were not correlated with bacteremia development. Significant regulation of certain SPI genes in bacteremic NTS strains after Caco-2 cell priming; bacteremia development might be influenced by the host immune response and the extent to which specific metabolism pathways in NTS strains can be prevented from invading the bloodstream.</p>","PeriodicalId":56117,"journal":{"name":"Journal of Microbiology Immunology and Infection","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142333171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Background: During the COVID-19 pandemic, there has been an increasing trend in healthcare-associated infections (HAIs) caused by carbapenem-resistant Acinetobacter baumannii (CRAB), posting a global public health concern. The heightened sensitivity of whole-genome sequencing (WGS) renders it an optimal and potent tool for monitoring outbreaks and tracing the transmission routes of nosocomial pathogens.
Method: We collected CRAB isolates from March 1, 2023, to April 6, 2023 in Chang Gung Memorial Hospital Lin Kou branch, a tertiary medical center in northern Taiwan. Any two or more isolates with the same identifiable capsular K-locus (KL) types were selected, and analyzed via WGS to identify putative transmission clusters, combined with epidemiologic and retrospective analysis on medical records to confirm risk factors and hidden transmission chains.
Result: A total of 48 non-redundant CRAB isolates were collected, belonging to ST2 of Pasteur MLST scheme and identifiable KL types of KL2, KL3, KL9, KL10, KL22, KL52. Excluding the KL types that was only found in 1 case, KL2 (n = 9, 22.5 %), KL3 (n = 24, 60 %), KL9 (n = 3, 7.5 %), and KL10 (n = 4, 10 %) were selected for further WGS analysis. Four distinct transmission clusters comprised of 2, 3, 10, and 23 cases were identified on a basis of phylogenetic status. 12 probable transmission chains were revealed, and 2 hidden transmission routes can be speculated.
Conclusion: This study referred to some hidden transmission chains that may be missed from traditional surveillance measures. Despite its low prevalence and high cost currently, implementing WGS could be a efficient, prompt, and unequivocal option for future MDRO infection control.
{"title":"Sequential use of capsular typing and whole-genome sequencing-based analysis for transmission of carbapenem-resistant Acinetobacter baumannii in a tertiary medical center.","authors":"Yi-An Way, Chong-Wei Huang, Wei-Chao Liao, Shiao-Wen Li, Ruei-Lin Chiang, En-Wei Hsing, Yi-Jiun Pan, Shian-Sen Shie, Yu-Chia Hsieh","doi":"10.1016/j.jmii.2024.08.014","DOIUrl":"https://doi.org/10.1016/j.jmii.2024.08.014","url":null,"abstract":"<p><strong>Background: </strong>During the COVID-19 pandemic, there has been an increasing trend in healthcare-associated infections (HAIs) caused by carbapenem-resistant Acinetobacter baumannii (CRAB), posting a global public health concern. The heightened sensitivity of whole-genome sequencing (WGS) renders it an optimal and potent tool for monitoring outbreaks and tracing the transmission routes of nosocomial pathogens.</p><p><strong>Method: </strong>We collected CRAB isolates from March 1, 2023, to April 6, 2023 in Chang Gung Memorial Hospital Lin Kou branch, a tertiary medical center in northern Taiwan. Any two or more isolates with the same identifiable capsular K-locus (KL) types were selected, and analyzed via WGS to identify putative transmission clusters, combined with epidemiologic and retrospective analysis on medical records to confirm risk factors and hidden transmission chains.</p><p><strong>Result: </strong>A total of 48 non-redundant CRAB isolates were collected, belonging to ST2 of Pasteur MLST scheme and identifiable KL types of KL2, KL3, KL9, KL10, KL22, KL52. Excluding the KL types that was only found in 1 case, KL2 (n = 9, 22.5 %), KL3 (n = 24, 60 %), KL9 (n = 3, 7.5 %), and KL10 (n = 4, 10 %) were selected for further WGS analysis. Four distinct transmission clusters comprised of 2, 3, 10, and 23 cases were identified on a basis of phylogenetic status. 12 probable transmission chains were revealed, and 2 hidden transmission routes can be speculated.</p><p><strong>Conclusion: </strong>This study referred to some hidden transmission chains that may be missed from traditional surveillance measures. Despite its low prevalence and high cost currently, implementing WGS could be a efficient, prompt, and unequivocal option for future MDRO infection control.</p>","PeriodicalId":56117,"journal":{"name":"Journal of Microbiology Immunology and Infection","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142333174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}