Several studies have established an association between the blood group type and susceptibility to infections. This study aimed to evaluate a correlation between the blood group type and the susceptibility to infection. 558 patients were enrolled in this study who attended at the Althawra Hospital, Ibb city, from March to August 2018. A blood sample was analyzed for complete blood count (CBC) and blood group. High frequency of infections affecting the digestive system (26.4%), while the less affected system is the urogenital system 5.9%. Patients with A blood group have increased probability to be infected by viruses than bacteria(Odds Ratio =1.430; 95% Confidence Interval =1.005 to 2.035; p= 0.05) and (OR=0.098; 95% CI=0.064 to 0.148; p<0.0001) respectively It was observed that blood group A persons were more liable to infection with hepatitis B virus than other groups (p=0.041; OR=1.704, 95% CI=1.053-2.773). The liability of O blood group patients for urogenital infections was less than non-O blood group patients by third (OR=0.353, 95% CI=0.158-0.789; p0.014). This study corroborates previous findings that showed that certain blood groups are more prone to infection by one agent than patients with other blood groups.

In response to rising carbapenem-resistant Enterobacterales (CRE), our study investigated carbapenemase-producing Klebsiella pneumoniae and non-K. pneumoniae epidemiology and genetics. We collected 76 clinical Enterobacterales and four stool surveillance Escherichia coli isolates resistant to ertapenem or imipenem. Using PCR and DNA sequencing, we assessed carbapenemases, extended-spectrum β-lactamases, and AmpC β-lactamases. Molecular typing via pulsed-field gel electrophoresis (PFGE) and a conjugation experiment examining resistance gene transfer were conducted. Among the 80 isolates, 96.2% (77/80) harbored at least one carbapenemase gene, with bla_OXA-48 in 87.5% (70/80). KPC-2 and IMP-8 carbapenemases were in 15.0% (12/80) and 22.5% (18/80) of the isolates, respectively, with 27.5% (22/80) having two or more carbapenemase genes. PFGE revealed diverse genotypes. PCR-based plasmid replicon typing identified IncA/C as the most prevalent type among K. pneumoniae isolates (26/29), and IncF and IncFIB among E. coli isolates (22/28). Conjugal transfer was successful for plasmids encoding OXA-48, CTX-M-3, CTX-M-14, CMY-2, and other β-lactamases, except the KPC-2 gene. In conclusion, our study highlights high carbapenemase prevalence in CRE, primarily OXA-48. Multiple carbapenemases within strains were common, and PFGE showed diverse patterns in these carbapenem-resistant isolates.

Potency test of influenza vaccine is currently performed using a single-radial-immunodiffusion (SRID) assay, which requires a reference antigen and anti-hemagglutinin (HA) serum as reference reagents. The reagents must be newly prepared each time the strain used for vaccine production is changed. Establishing reference reagents with consistent quality is, therefore, crucial to accurately and precisely conduct vaccine potency tests. Here, we established the reference reagents for the SRID assay to conduct lot release tests of quadrivalent influenza vaccines in Japan for the 2022/23 influenza season. The potency stability during storage of some reference antigens was confirmed. Furthermore, we evaluated the cross-reactivity of each antiserum raised against the HA protein of two lineages of influenza B virus toward the different lineage of influenza B virus antigen to select a suitable procedure of SRID assay for accurate measurement. Finally, the intra-laboratory reproducibility of the SRID assay using the established reference reagents was validated, and then the SRID reagents had sufficiently consistent quality comparable to that of the reagents used for testing vaccines in past influenza seasons. Our study could contribute to the quality control of influenza vaccines.

In Japan, rubella antibodies are measured in all pregnant women in order to detect subclinical infection. The study aimed to assess the validity of measuring rubella antibodies to detect subclinical rubella among pregnant women in Japan. This single-center, retrospective study measured rubella hemagglutination inhibition (HI) titers and rubella-specific IgM antibody index values (IgM-values). IgM-values were measured by enzyme immunoassay, and IgM-values > 1.2 were considered positive. Of 14965 pregnant women who were included, 186 (1.2%) were IgM-positive. Only one patient was clinically diagnosed with rubella (HI titer, 1:2048; IgM-value, 10) and developed a fever and skin rash. She decided to terminate her pregnancy without a repeat blood test. Of the IgM-positive patients, 136 (73.1%) had rubella HI titers of < 1:256. The correlation coefficient of rubella HI titers and IgM-values was weakly positive (0.2527; p < 0.0001). This study showed that the single combination of rubella HI and rubella-specific IgM measurements alone did not detect subclinical rubella. Creating awareness among pregnant women by informing them that almost all rubella-specific IgM-positive individuals without symptoms are not acutely infected could decrease their anxiety and prevent unnecessary termination of pregnancies.

Legionella pneumophila serogroup (SG) 1, the main cause of Legionnaires' disease, can be diagnosed with urinary antigen testing kits; however, lower respiratory tract specimen culture is necessary to identify L. pneumophila SG 2–15. We attempted to detect L. pneumophila SG-specific genes in a culture-negative sputum specimen from a patient with pneumonia suspected to have Legionnaires’ disease. Two multiplex PCR methods targeting L. pneumophila were modified and amplicons considered to be SG13 specific were detected. Direct sequencing revealed that the amplicons were identical to the nucleotide sequence of L. pneumophila SG13. Based on the presentation and clinical course (fever, muscle pain, disturbance of consciousness, high C-reactive protein titer, rhabdomyolysis, hypophosphatemia, and symptomatic improvement with levofloxacin treatment) in combination with the detection of L. pneumophila SG-specific genes, we suspected L. pneumophila SG13 pneumonia. L. pneumophila non-SG1 pneumonia is thought to be underestimated due to of its difficult laboratory diagnosis. The modified multiplex PCR system for lower respiratory tract specimens shown in this study is likely to increase the diagnosis of Legionnaires' disease caused by L. pneumophila SG13 and other SGs.

Despite the HBV vaccine being routinely administered in many countries, the death rate remains significant. Antiviral medications are available for the treatment of HBV infection, but patients encounter various serious complications in cases of chronic HBV infection. The failure of serological tests to detect early viral replication prevents early treatment response. Recently, many studies have demonstrated significant advantages of the loop-mediated isothermal amplification (LAMP) assay over serological testing and PCR for the rapid detection of microbial pathogens. This study developed a rapid, sensitive, and portable system-integrative LAMP assay to detect Hepatitis B DNA in plasma samples. The final optimized assay was achieved with an amplification time of less than 45 minutes at 62°C. As a result of testing 77 HBV-positive plasma samples with known Cq values, the LAMP assay showed 100% specificity, 92, 20% sensitivity, and a detection limit of 10 copies/µL. Our results showed that the colorimetric LAMP assay is a sensitive, efficient, and highly reliable assay for the rapid detection of HBV and has the potential to be used as a screening test in areas where poor laboratory facilities and limited resources are available.

For many viruses, cleavage activation of membrane fusion protein by host proteases is required for infection. This knowledge is based on the historical studies on Sendai virus in the 1970s. From the 1970s to the 1990s, the avian influenza virus and Newcastle disease virus were studied, showing a clear link between virulence and host proteases' cleavage activation of viral membrane fusion proteins (hemagglutinin and fusion proteins). In these viruses, the cleavage of viral membrane fusion proteins by furin is the basis for their high virulence. Subsequently, from the 2000s to the 2010s, the importance of TMPRSS2 in activating membrane fusion proteins of various respiratory viruses, including seasonal influenza viruses, was demonstrated. In late 2019, SARS-CoV-2 emerged and caused a pandemic. This virus continues to mutate, producing variants that cause a global pandemic. The spike protein of SARS-CoV-2 is characterized by two cleavage sites, each undergoing cleavage by furin and TMPRSS2 to achieve membrane fusion activity. SARS-CoV-2 variants show altered sensitivity to these proteases. Thus, studying the cleavage activation of the membrane fusion protein by host proteases is still critical to understanding the ongoing pandemic and developing countermeasures against it.

CoronaVac emerged as one of the most widely administered COVID-19 vaccine in Indonesia. Previous research has documented various figures regarding its effectiveness in protecting against COVID-19 in several countries. Therefore, this research aims to assess the long-term immunogenicity profile in individuals with comorbidities or history of SARS-CoV-2 infection. The level of total anti-N Ig and anti-S-RBD Ig at 7 weeks and 26 weeks after receiving the second dose was observed in 194 health workers. The participants were divided into groups based on their comorbidities and history of SARS-CoV-2 infection. The results showed that there was no difference in both antibody titers between healthy and comorbid groups without any history of SARS-CoV-2 infection. The level of total anti-nucleocapsid Ig was significantly lower compared to the infected groups, and similar results were obtained in the total anti-S-RBD Ig level. Based on the results, CoronaVac induced a lower specific antibodies response compared to natural infection and also reduced immunogenicity in the long term.

We studied 226 patients in Toyama Prefecture, notified with COVID-19 during the first wave between March 30 and May 18, 2020. Of the 226 patients, 22 (9.7%) died, of whom most (95%) were aged ≥65 years. A large cluster comprising 59 patients (41 residents and 18 staff members) was identified in a nursing home on April 17. No deaths occurred among the staff members, but 12 of the 41 cases in residents (29%) died. Although the Ct values were significantly lower in the 20–64 and the ≥65 years age-groups than in the age <20 years age-group, no correlation was found between the Ct values and the severity, fatal outcome, or secondary infection. The haplotype network of 145 SARS-CoV-2 isolates (64%) from 226 patients was analyzed. The viral genomes of the case groups differed by less than five nucleotide bases. These data suggest that SARS-CoV-2 strains, which were initially introduced into Toyama Prefecture during late March and early April 2020, and their closely related strains, identified as the lineage B.1.1, circulated during the first wave. The reduced inter-prefectural mobility of local residents may support a lack of strain diversity in SARS-CoV-2 during a state of emergency in the first wave.

General vaccine hesitancy is a global concern. Clarification of the general vaccination readiness and psychological factors comprising it is an important issue. Previous studies have reported that Japan has one of the lowest vaccine confidence levels worldwide. However, the status of other psychological factors comprising general vaccination readiness in Japan remains unclear. Therefore, we aimed to clarify the status of seven psychological factors comprising general vaccination readiness and their patterns in Japan. This descriptive study utilized data from a large-scale nationwide internet survey (JASTIS 2023 study, n = 31,037). The seven psychological factors were assessed using the 7C of vaccination readiness scale. Cluster analysis was performed using k-means++ clustering to clarify the patterns. Of the seven factors, support for social monitoring of people refusing vaccination (e.g., vaccine passport) was very low among the participants. Cluster analysis showed that the participants’ vaccination readiness could be classified into six patterns, of which the very low vaccination readiness cluster, with the lowest scores for most of the psychological factors, accounted for 11.1% and was more common among those aged 30–49 years (13.1–16.4%). Individuals comprising this cluster may tend to refuse to receive any recommended vaccines.

Using anticancer drugs as an example, we examined the possibility of reusing residual drugs. The use of residual drugs is not widespread because of concerns regarding bacterial contamination. We mixed anticancer drugs with bacteria and investigated their effects on bacterial growth. The anticancer drugs carboplatin, paclitaxel, etoposide, irinotecan, methotrexate, and 5-fluorouracil (5-FU) were mixed with Staphylococcus aureus, Enterococcus faecalis, Serratia marcescens, and Escherichia coli. After a certain period, the number of bacteria was counted. Irinotecan showed no antibacterial activity, whereas 5-FU showed high antibacterial activity against the bacteria tested. The 5-FU also showed a minimum inhibitory concentration value in the range of 8–80 μg/mL, depending on the bacterial species. The 5-FU dose-dependently inhibited S. aureus growth at more than 0.8 µg/mL. Since protein synthesis systems are reportedly antibiotic targets, we used a cell-free protein synthesis system to confirm the mechanism of the anticancer agent’s antibacterial activity. The 5-FU and methotrexate had direct inhibitory effects on protein synthesis. It is suggested that even if the residual drugs are contaminated with bacteria, there will be no microbial growth or microbes will be killed by the drug. With careful monitoring, the 5-FU could potentially be used for antimicrobial purposes.

Universal screening for Streptococcus agalactiae, Group B Streptococcus (GBS), in pregnant women is important for preventing severe infectious diseases in neonates. The subculture method using selective enrichment broth has been reported to significantly improve GBS detection in the US; however, this method is not widely practiced in Japan. An insufficiency of large-scale validation is one of the reasons; therefore, we validated the utility of the subculture method in collaboration with multiple facilities. A total of 1957 vaginal–rectal swab specimens were obtained from pregnant women at 35–37 gestational weeks from March 1, 2020 to August 30, 2020 at Fukushima Medical University Hospital, Aiiku Hospital, Kitano Hospital, and the University of the Ryukyus Hospital. Three methods, such as conventional direct agar plating, subculture using selective enrichment broth, and direct latex agglutination (LA) testing with incubated broth were performed for GBS detection and discrepant results were confirmed using real-time PCR. The GBS detection rates for direct agar plating, subculture, and direct LA testing were 18.2% (357/1957), 21.6% (423/1957), and 22.3% (437/1957), respectively. The use of selective enrichment broth showed results in highly-sensitive GBS detection and is therefore recommended for GBS screening to prevent GBS-related infectious diseases in neonates in Japan.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is prevalent worldwide, and effective and safe vaccines against the virus have been developed. Although trends in antibody titers after vaccination and/or SARS-CoV-2 infection have been reported, the length and frequency of the measurements are limited. This case report describes the long-term and detailed trends in the anti-SARS-CoV-2 S protein receptor-binding domain (S-RBD), repeatedly measured after vaccination and/or infection in three healthcare workers. All healthcare workers received 30 μg of the mRNA vaccine, BNT162b2, during all vaccinations. The peak value of the SARS-CoV-2 S-RBD titer reached at 1–2 week(s) after vaccination, decreased by half within 8 weeks after the vaccination, and the peak values of the antibody titer increased with repeated vaccinations. In contrast, after SARS-CoV-2 infection, the peak value of the antibody titer reached at 4–8 weeks after the infection, but the elevated antibody titer remained up to 16 and 40 weeks after the peak. The present case report shows long-term and detailed trends of SARS-CoV-2 S-RBD titer, with different patterns after vaccination and/or SARS-CoV-2 infection.

Latent tuberculosis infection (LTBI) with fibrotic lesions (FL) can progress to active tuberculosis (TB). Previous studies did not use interferon-gamma release assays (IGRAs) but used tuberculin skin tests for LTBI diagnosis, whose specificity was lower. This study evaluated the incidence of active TB among LTBI with FL who were diagnosed with IGRAs in Nishinari District, Osaka City. In total, 54 men were registered with 68.7 years old of a mean age, ten (18.5%) were homeless, and 36 (66.7%) were welfare recipients. Overall, with the median period of observation of 1,084 days (range: 64-2,907 days), an incidence rate of active TB among LTBI with FL was 1.18 cases per 100 person-years (95% confidence interval: 0.32-4.29). Among 19 (35.2%) who had never been treated with anti-TB therapy, one (5.3%) progressed to active TB, and among 30 (55.6%) who completed the treatment, one (3.3%) progressed to active TB. The others five did not have TB. We revealed the incidence of active TB among LTBI with FL in an urban vulnerable population for the first time, using IGRAs for the diagnosis of LTBI. A higher incidence than that reported in previous studies reinforces the importance of strategies, including chest radiography screening and LTBI treatment.

We evaluated cell invasion ability (CIA) of noninvasive Streptococcus dysgalactiae subsp. equisimilis using human keratinocyte and determined associations of CIA populations with their host and microbiological traits. Forty-two isolates from humans and companion animals were selected with host information. We measured human keratinocyte CIA, in addition to virulence-associated gene (VAG, spegg–ska–scpA–inlA–sicG–brpA–prtF1–prtF2–lmb–cbp–srtp1–srtp2) detecting, emm genotyping, multilocus sequence typing, and antimicrobial resistance (AMR) phenotyping/genotyping. We designated CIA values higher than mean of all isolates as high-frequency and CIA values lower than mean as low-frequency. Differences in CIA from different sources and Lancefield groups were assessed. We analyzed associations between high-/low-frequency CIA and VAG, emm genotype, sequence type/clonal complex, and AMR phenotype/genotype. Based on mean (19.368 colony-forming units/100 cells) of forty-two isolates, eight isolates had high-frequency CIA, whereas thirty-four had low-frequency CIA. We found an association of low-frequency CIA population with group G isolates, whereas there was an association between high-frequency CIA population and group C isolates. We observed associations between low-frequency CIA and oral/respiratory tract-origin, ska, scpA, and lmb detected, and AMR phenotype. Our observations suggest potential associations of high-/low-frequency CIA with group, source, VAG, and AMR phenotype.

Klebsiella pneumoniae (Kp) associated with hospital acquired infections are extensively-drug resistant (XDR), making treatment problematic. Understanding the genetic epidemiology of XDR -Kp can determine their potential to be hypervirulent (hv) through the presence of siderophores. We characterized genomes of 18 colistin-resistant XDR-Kp isolated from 14 patients with complicated urinary tract infection in an Indian healthcare facility. 18 organisms comprised STs: ST14 (9/18), ST147 (5/18), ST231 (2/18), ST2096 (1/18), and ST25 (1/18). Many patients in one ward were infected with the same ST, indicating a common infection source. Some patients had recurrent infections with multiple STs that were circulating in that ward, providing evidence for hospital transmission. Beta lactamase genes (bla_CTX-M-1, bla_SHV, and bla_ampH) were present in all isolates. bla_NDM-1 was present in isolates 15/18, bla_OXA-1 was present in isolates 16/18, bla_TEM-1D was present in 13/18 isolates, and bla_OXA-48 was present in isolates 14,19 and 30. Disruption of mgrB with various IS elements was responsible for colistin resistance in 6 isolates. The most common K type among these isolates was K2 (10/18). One XDR convergent hv-Kp ST2096 was associated with prolonged hospitalisation (iuc+ybt+bla_OXA-1+bla_OXA-48).Convergent XDR-hv-Kp detected has outbreak potential, warranting effective antimicrobial stewardship and infection control.

Equine botulinum antitoxin is one of the most popular countermeasures for human botulism. The unitage of the antitoxin product is defined according to national minimum requirement or pharmacopoeia in each country by referring to national standard antitoxins for four types (A, B, E, and F). With the expected depletion of the national standard antitoxins, replacement national standard antitoxins are produced and standardized through collaboration of the National Control Laboratory and other participants, including manufacturer(s). Therefore, Japanese National Standard Botulinum Antitoxin Type A, Equine, was replaced according to the results of a collaborative study involving the National Institute of Infectious Diseases and KM Biologics Co., Ltd. The unitage of the replacement material was determined through mouse neutralization tests, which involved toxin-antitoxin mixture injection at pH 7.0. Potency value of 440 units/vial was obtained. However, the Japanese Minimum Requirement for Biological Products was revised, and the neutralization reactions were repeated at pH 6.0, for which considerably different potency value (656 units/vial) and survival profile of mice were obtained. In September 2021, the replacement material, Japanese National Standard Botulinum Antitoxin Type A, Equine, lot 2, was established with potency value of 656 Units/vial. The impact of pH-dependent change in potency on antitoxin quality control is discussed.

To demonstrate the transmission cycle of Shimokoshi type Orientia tsutsugamushi in Shimane prefecture, field rodents were captured from areas where four human infections caused by the pathogen were reported. The rodents were investigated for the transmission cycle of the pathogen based on the pathogen’s genome, antibodies against the pathogen, and vector of the pathogen (Leptotrombidium palpale). In addition, the vector was captured from soil of the study areas. A total of 44 rodents was captured. No DNA of O. tsutsugamushi were detected in the blood or spleen samples using real-time polymerase chain reaction. However, the specific antibody against the pathogen was detected in 2 out of 44 (4.5%) rodents by the indirect immunoperoxidase method, indicating the presence of the pathogen in the study areas. Although 29 L. palpale were identified, DNA detection was not performed, because of insufficient number of vectors according to the DNA detection rate in previous studies. However, the identification of the vector as well as the specific antibody in rodents suggest the presence of the transmission cycle of Shimokoshi type O. tsutsugamushi in Shimane prefecture.

Salmonella enterica subsp. enterica serovar Typhimurium has recently emerged worldwide as a producer of extended-spectrum β-lactamase (ESBLs). However, such resistant clinical isolates are still rare in Japan. The common types of ESBLs found are the CTX-M type β-lactamases, including novel ones such as CTX-M-64. CTX-M-64 has a chimeric structure that is a combination of the CTX-M-1 and CTX-M-9 groups. In 2017, S. Typhimurium was isolated from cultures of stool, blood, and urine of an 82-year-old man. Here, we describe the discovery of a clinical isolate of S. Typhimurium in Japan. Antimicrobial susceptibility testing revealed that S. Typhimurium was resistant to third- and fourth-generation cephalosporins, including ceftazidime and monobactam. The MICs of ceftazidime and ceftriaxone were restored by clavulanic acid. Whole-genome sequencing analysis revealed that S. Typhimurium had bla_CTX-M-64 gene on an IncHI2/IncHI2A-type plasmid with an assembly length of 174,477 bp. The genetic structure of the region surrounding the bla_CTX-M-64 gene, ISKpn26-ΔISEcp1-bla_CTX-M-64-orf477, was only shared with the chromosome sequence of S. Typhimurium detected from food-producing chicken in Guangdong, China. Although rare, S. Typhimurium can induce bloodstream infections and produces ESBLs. This is the first report of a CTX-M-64-producing Enterobacterales clinical isolate of domestic origin in Japan.