Aims To estimate the preventable pneumococcal disease burden by 21-valent pneumococcal conjugate vaccine (PCV21) compared to PCV20 for the national immunization program for adults aged 65 years or older in Japan. Methods Serotype distribution among isolates and the annual incidence of invasive pneumococcal disease (IPD) in adults were monitored. The numbers of IPD or pneumococcal community-acquired pneumonia (pCAP) cases preventable by immunization with PCV20 or PCV21 were estimated according to reported vaccine efficacy and duration of protection in older adults. Data from our nationwide study of adult IPD surveillance and a multicenter study of pCAP were used. Results The mean annual incidence of adult patients with IPD caused by all serotypes among adults aged ≥65 years, which declined during the COVID-19 pandemic period, recovered to 89% of the pre-pandemic level in 2025. During 2023–2025, the proportion of PCV20-non-PCV21 serotypes was 8.5% for adults aged ≥65 years. At the current vaccination coverage rate of 40%, the numbers of preventable IPD cases (per person per year) by PCV20 and PCV21 were 36 and 53, respectively. The preventable numbers of pCAP cases by PCV20 and PCV21 were 2,821 and 4,765, respectively. The estimated number of preventable pCAP cases was approximately 80–90 times higher than that of preventable IPD cases. Conclusion Our data indicate that PCV21 could prevent 1.5–1.7 times as many pneumococcal disease cases as PCV20 among adults aged ≥65 years in Japan. However, PCV20 should be considered if the incidence of adult IPD cases caused by PCV20-non-PCV21 serotypes increases. ### Competing Interest Statement The authors have declared no competing interest. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study was reviewed and approved by the Medical Research Ethics Committee of JIHS, NIID (approval no. 707) and conducted in accordance with the tenets of the Declaration of Helsinki. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data will be made available upon reasonable request. the Ministry of Health, Labor and Welfare Humanitarian Assistance Program, JPMH25HA1001
Shigella species and enteroinvasive Escherichia coli (EIEC) have highly similar biochemical, serological, and pathogenic profiles, making their differentiation challenging. Although the 25-base sequence ECA75F within the 16S rRNA gene has been used as a potential marker in PCR-based differentiation methods, some environmental Shigella spp. closely related to E. coli possess this sequence, while it remains absent in clinical Shigella spp. Hence, we aimed to further explore the relationships between E. coli and Shigella spp. employing multilocus sequence typing (MLST)-based phylogenetic analysis of 42 clinical Shigella spp. isolates and 32 E. coli isolates, among which 28 were classified as EIEC. Shigella isolates clustered within specific clades, whereas E. coli isolates, including EIEC, formed largely distinct clusters with limited overlap. Three O-untypable EIEC isolates clustered within the Shigella ST245 clonal complex (CC245), highlighting the complexity of classification within this group. Additionally, a dual-probe real-time PCR (DpRT-PCR) assay targeting both the ECA75F and the invasion plasmid antigen H gene (ipaH) was developed. This assay demonstrated sensitivities and specificities of 100% versus 96.7% for Shigella spp. and 88.3% and 100% for EIEC, respectively. Overall, these findings demonstrate that the DpRT-PCR assay provides a rapid and effective method for differentiating Shigella spp. from EIEC. Furthermore, for cases with ambiguous genetic profiles, such as EIEC isolates grouped with CC245, MLST-based phylogenetic analysis may provide additional resolution and clarity.IMPORTANCEShigella and enteroinvasive Escherichia coli (EIEC) cause clinically indistinguishable diarrheal diseases, yet they differ in surveillance reporting, outbreak control measures, and public health responses. However, routine laboratory identification often fails to clearly differentiate these pathogens because of their close genetic relatedness and overlapping biochemical characteristics. In this study, we performed a genome-based reassessment of the ECA75F sequence and developed a rapid and robust dual-probe real-time PCR assay that accurately distinguishes Shigella spp. from EIEC. This method overcomes the limitations of conventional PCR assays and provides a reliable tool for frontline laboratories. The ability to differentiate these pathogens quickly and accurately will improve case classification, guide appropriate public health interventions, and strengthen epidemiological monitoring in both endemic settings and outbreak investigations.
We previously reported that the cytopathic effect (CPE) and single-round infectious particles (SRIPs) assays are useful alternatives to the focus-forming assay method for testing human Japanese encephalitis virus (JEV) susceptibility. In this study, we investigated whether these alternative methods were useful for testing JEV antibodies in pig sera in the same survey. A total of 240 serum samples from 6-month-old pigs were used in this study. Antibody titers were evaluated using four methods: the hemagglutination inhibition (HI) assay, currently used for pig serum in the national epidemiological surveillance program for vaccine-preventable diseases in Japan; the focus-forming assay, which is currently used for human serum; and the CPE and SRIPs assays, both previously evaluated using human serum. Unfortunately, the antibody titers in the HI assay showed almost no correlation with those of other methods. However, if the presence or absence of antibodies is determined instead of titer, using each assay method, a concordance rate > 90% was observed for all combinations of assay methods. Among the evaluated assays, the SRIPs assay showed excellent agreement with conventional neutralization assays and may serve as a practical alternative for evaluating JEV neutralizing antibodies in pigs.
We report a case of bacteremic M1UK Streptococcus pyogenes pneumonia in an immunocompetent patient, which improved with adjunctive clindamycin therapy. In vitro, clindamycin consistently suppressed expression of streptococcal pyrogenic exotoxin A (speA) in M1UK strains but not in the M1global strain, whereas levofloxacin showed no suppressive effect. These findings support a potential antitoxin role of clindamycin in M1UK infections.
Optogenetic dimerization modules are widely used to regulate protein function, yet their behaviour within folded enzymes remains incompletely understood. Here, we engineered vesicular stomatitis virus by inserting an intramolecularly tethered light-inducible dimerizer into the viral RNA-dependent RNA polymerase [large (L) protein], enabling assessment of its effects on early viral transcription and viral replication. Blue light illumination enhanced viral replication, but reduced temperature produced a similar increase in viral replication even in the absence of light. In addition, a thermally stabilized dimerizer variant supported robust replication under dark conditions. These observations suggest that early viral transcription and viral replication are influenced by the structural and biophysical properties of the inserted dimerizer and their temperature dependence, rather than by light alone. Structural modelling suggested that permissive insertion sites are located within or adjacent to regions with low predicted Local Distance Difference Test (pLDDT) scores, whereas non-permissive insertions showed greater predicted local structural deviations, particularly in the capping domain. Although these analyses are based on predicted structures, the observed structural differences are consistent with the functional differences among insertion sites. Together, our results show that intramolecular optogenetic modules enable light- and temperature-dependent modulation of early viral transcription and replication. While the structural analyses are based on predicted models, they provide a useful framework for identifying permissive insertion sites and generate testable hypotheses regarding how the structural and biophysical properties of the inserted dimerizer may influence polymerase function.
