The maintenance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among wildlife populations poses a potential risk for the emergence of novel variants. Therefore, monitoring SARS-CoV-2 infection among animals is crucial. As urban rodents live in close proximity to human habitats, there is concern that they may be a potential source of zoonoses. To examine the prevalence of SARS-CoV-2 in rodent populations, we analyzed 128 serum samples and 129 oral swabs collected from 128 brown rats (Rattus norvegicus) and 2 black rats (Rattus rattus) captured for pest control purposes in Tokyo, Japan, between May and December 2023. A virus-neutralizing test using the Omicron variant revealed no evidence of SARS-CoV-2 infection in these populations. Real-time RT-PCR from oral swabs did not detect any SARS-CoV-2 RNA-positive rats. These results indicate the low probability of SARS-CoV-2 circulation among rat populations in Tokyo.

The spread of antimicrobial-resistant organisms (AROs) poses a major threat to animal and human health. In Japan, the estimated disability-adjusted life years (DALYs) due to infections with AROs is 137.9 per 100,000 persons, with methicillin-resistant Staphylococcus aureus (MRSA) being the main contributor. The factors that can contribute to DALYs in Japan include younger age and a higher number of deaths in patients with MRSA bacteremia. Moreover, longer hospital stays may contribute to higher rates of MRSA bacteremia in Japan than in Western countries. We reviewed diagnosis procedure combination data collected from January 1, 2016, to December 31, 2020, in an acute care hospital in Tokyo, Japan. We found that the median time from admission to MRSA bacteremia onset was 26 days, which is longer than that in Western countries but similar to that in South Korea. Further, our cohort was older than that in the United States and South Korea, potentially contributing to the higher number of years of life lost in Japan. These results underscore the need to develop strategies to reduce hospitalization in Japan. Larger multicenter studies are needed to comprehensively evaluate the economic and health burden of MRSA bacteremia in Japan.

An active epidemiological investigation of COVID-19 cases in the Setagaya ward of Tokyo revealed that household transmission was the main route of infection spread. This study aimed to identify the factors affecting household transmission in patients diagnosed with COVID-19 and their cohabitants, during the wild type virus (December 2020) and alpha variant epidemic (May 2021). Index case factors significantly associated with household transmission for both wild type (WT) and alpha variant (AV), were at least 3 days from onset to diagnosis (WT: risk ratio [RR] 1.44, 95% confidence interval [CI] 1.16-1.79/AV: RR 1.66, CI 1.32-2.08), and a household size of three or more people (WT: RR 1.37, CI 1.10-1.72/AV: RR 1.29, CI 1.05-1.59). There were also significant differences in age ≥ 65 (RR 2.39, CI 1.26-4.54) and symptomatic at diagnosis (RR 3.05, CI 1.22-7.63) in index cases of WT. Among cohabitants, factors associated with household transmission for both strains were being the spouse/partner of the index case (WT: RR 1.68, CI 1.21-1.82/AV: RR 1.97, CI 1.59-2.43) and at least 3 days from onset to diagnosis of the index case (WT: RR 1.48, CI 1.34-2.10/ AV: RR 1.86, CI1.52-2.28). Early diagnosis and isolation are effective for preventing household transmission.

The combination of the four regions of vacA with cagA, cagE, dupA genes and cagA-EPIYA motifs, was studied to find the most likely combination that can be used as a disease determinant marker in Moroccan population. A total of 838 H. pylori positive obtained from consenting patients, that were previously analyzed by PCR to characterize vacA-s -m, -i regions, cagE status and cagA 3’ region polymorphism, were used to characterize vacA-d region and to determine dupA gene status. The analysis shows the predominance of the less virulent combination (vacA(s2m2i2d2)dupA(-)cagE(-)cagA(-)), and shows that the risk of gastric cancer is 13.33 fold higher (1.06–166.37)) in patients infected by strains harboring vacA(s1m1i1d1)dupA(-)cagE(+)cagA(2EPIYA-C) compared to patients with gastritis without lesions and infected by H.pylori strains harboring vacA(s2m2i2d2)dupA(-)cagE(-)cagA(-). The infection with strains harboring vacA(s1m1i1d1)dupA(+)cagE(+)cagA(1EPIYAC) genotype combination represents a risk factor for gastric ulcer and duodenal ulcer (the Odds Ratio (95% CI) were 16 (1.09–234.24) and 6.54 (1.60–26.69) respectively) compared to patients with gastritis without lesions. These results suggest that the combination of the active form of vacA genotypes, dupA gene status and the number of EPIYA-C motif may be considered helpful markers to discriminate between several gastric diseases.

Hand, foot and mouth disease (HFMD) was one of the most common infectious disease in the past few decades. After 2013, coxsackievirus A6 (CVA6) has replaced enterovirus 71 (EV-A71) and coxsackievirus A16 (CVA16), becoming the predominant pathogen responsible for HFMD in many areas in China. The objective of this study is to investigate the genetic characteristics and molecular epidemiology of CVA6 in Linyi from 2022 to 2023. A total of 965 HFMD cases were enrolled in this study and analyses based on VP1 nucleotide sequences were performed to determine the evolutionary trajectory of CVA6. In 2022, 281 (281/386, 72.8%) were positive for enterovirus (EVs), and 217 (217/281, 77.2%) were CVA6 positive. In 2023, 398 (398/579, 68.7%) samples were positive for EVs, and 243 (243/398, 61.1%) were CVA6 positive. Six sequences were selected from each year for the homology analysis. The results showed that 12 strains isolated in Linyi were far from the prototype strain (AY421764) and the first CVA6 strain reported in China (JQ364886). Phylogenetic analysis showed that the CVA6 strains isolated in Linyi all belonged to D3 subgenotype. CVA6 is emerging as a common pathogen causing HFMD in Linyi, and continuous surveillance of HFMD etiological agents is necessary.

The widespread prevalence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli limits treatment options and is a worldwide problem. The aim of this study was to investigate the antimicrobial susceptibility and ESBL-type of 204 strains of CTX-M-type ESBLs-producing E. coli isolated from 2011 to 2017 in the Chubu region of Japan. Minimal inhibitory concentrations were determined in accordance with the guidelines of the Clinical and Laboratory Standards Institute. Genes encoding CTX-M group β-lactamases were detected by PCR amplification. The CTX-M subtypes were determined using sequence analysis. The CTX-M-9 group was the most frequently detected ESBL group, and CTX-M-27 was the most frequently detected ESBL gene. CTX-M-15-producing strains showed significantly lower rates of susceptibility to tazobactam/piperacillin (TAZ/PIPC) than those by CTX-M-14 and -27-producing strains. Additional analysis of secondary β-lactamases revealed that most of the OXA-1-positive strains were CTX-M-15-producing strains (94.7%). These strains displayed significantly lower susceptibility rates to TAZ/PIPC (47.4%), sulbactam/ampicillin (SBT/ABPC) (0.0%), and amikacin (AMK) (73.7%) than those by OXA-1-negative strains, suggesting that the high non-susceptibility rate of the CTX-M-15-producing strain was due to the co-carriage of OXA-1. The CTX-M-15-producing strains showed reduced susceptibility to TAZ/PIPC, SBT/ABPC, and AMK, presumably due to the co-carriage of OXA-1.

Campylobacter jejuni is one of the major bacteria that causes diarrhea in humans. It has been associated with many cases of food poisoning in Japan caused by eating raw or undercooked chicken meat, chicken liver, and grilled chicken (Yakitori). Campylobacter jejuni is also known as the preceding infection pathogen of Guillain–Barré syndrome (GBS), which causes considerable health impact on humans. In January 2022, in a case of C. jejuni food poisoning that occurred at a restaurant in Tokyo, one of four patients with diarrhea developed GBS. The poisoning is presumed to have been caused by undercooked chicken dishes. Recently, it was one of the common cases in Japan. Moreover, C. jejuni isolates from three patients, including the patient with GBS, had the same genotype (ST22, HS19, and LOS A). This genotype was frequently detected from patients with GBS in our past surveys. Our findings confirmed that the patient developed GBS via food poisoning after consuming undercooked chicken dish.

Persistent inflammation in chronic HIV infection may affect immune responses against SARS-CoV-2 infection. Plasma levels of multiple proinflammatory cytokines during acute SARS-CoV-2 infection were assessed in people with HIV (PWH) with effective cART. There were no significant differences in any of the tested cytokines between COVID-19 severity in PWH, while most of them were significantly higher in individuals with severe disease in HIV-uninfected individuals, suggesting that excess cytokines release by hyper-inflammatory responses does not occur in severe COVID-19 with HIV infection. The strong associations between the cytokines observed in HIV-uninfected individuals, especially between IFN-α/TNF-α and other cytokines, were lost in PWH. The steady state plasma levels of IP-10, ICAM-1, and CD62E were significantly higher in PWH, indicating that PWH are in an enhanced inflammatory state. Loss of the several inter-cytokine correlations were observed in in vitro LPS stimuli-driven cytokines production in PWH. These data suggest that inflammatory responses during SARS-CoV-2 infection in PWH are distinct from those in HIV-uninfected individuals, partially due to the underlying inflammatory state and/or impairment of innate immune cells.

Clusters of nosocomial coronavirus disease 2019 (COVID-19) were reported globally during the recent pandemic. Unfortunately, these clusters negatively impacted inpatient morbidity, mortality, and hospital functions. Using epidemiological data and whole genome sequencing (WGS) of SARS-CoV-2, the present study investigated an outbreak of COVID-19 at a university hospital. Eight inpatients and 13 healthcare workers tested positive for SARS-CoV-2 during a one-month period. Whole genome sequencing (WGS) of the virus in 11 patients revealed that two variants of concern belonging to the Omicron sublineages, BA.2.3 and BA1.1.2, had caused the outbreak during a time when the proportion of the Omicron lineage in the community was changing. When variants of concern are undergoing mutation, a response to the outbreak should be made with multiple variants in mind, even in the absence of epidemiological data showing close contact or other potential vectors of infection, and awareness about infection prevention and control should be raised to safeguard patient safety.

The number of syphilis cases in Tokyo has been found to increase in recent years. We conducted a descriptive epidemiology to elucidate the actual status of syphilis. Data on age, sex, disease stage, and presumed sexual partner of syphilis cases reported in Tokyo were tabulated and analyzed. A total of 9,419 syphilis cases have been reported between 2019 and 2022. There was a particularly sharp rise in the number of reported cases from 2021 to 2022. Comparing 2020 to 2022, the number of syphilis cases among women in their 20s, rapidly increased, more than triple. Furthermore, the number of pregnant women among syphilis cases increased in 2022. Despite the rapid increase in the number of young women with syphilis, there has been no increase in cases of congenital syphilis. One of the reasons may be that syphilis was detected early in pregnancy due to the high antenatal checkup rate in Tokyo. However, the continued incidence of syphilis among young women may increase congenital syphilis in the future. Public health strategy should include educational activities targeting high-risk populations or adolescents, early and appropriate testing, and treatment for preventing progression of syphilis.

Biofilm-producing methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative Staphylococci (MR-CoNS) are a clinical challenge for the treatment of healthcare-associated infections. As alternative antimicrobial options are needed, we aimed to determine the effect of curcumin-chitosan magnetic nanoparticles on the biofilm of staphylococcal clinical isolates. MRSA and CoNS clinical isolates were identified by MALDI-TOF mass spectrometry. Antimicrobial susceptibility testing was performed by broth microdilution. Nanoparticles were synthesized by co-precipitation of magnetic nanoparticles (MNP) and encapsulation by ionotropic gelation of curcumin (Cur) and chitosan (Chi). Biofilm inhibition and eradication by nanoparticles with and without the addition of oxacillin was assessed on staphylococcal strains. Cur-Chi-MNP showed antimicrobial activity on planktonic cells of MRSA and MR-CoNS strains and inhibited biofilm of MRSA. The addition of OXA to Cur-Chi-MNP increased biofilm inhibition and eradication activity against all Staphylococci strains (p=0.0007); higher biofilm activity was observed in early biofilm stages. Cur-Chi-MNP showed antimicrobial and biofilm inhibition activity against S. aureus. The addition of OXA increased biofilm inhibition and eradication activity against all Staphylococci strains. A combination treatment of Cur-Chi-MNP and OXA could be potentially used to treat staphylococcal biofilm-associated infections in its early stages before the establishment of biofilm bacterial cells.

Since the COVID-19 pandemic has affected the epidemiological pattern of pharyngoconjunctival fever (PCF) caused by human adenovirus (HAdV), the prevalence and type distribution of HAdVs associated with PCF among children in Osaka, Japan, between 2019 and 2023 have been analyzed. The number of reported PCF cases in Osaka decreased from 2020 to 2022, followed by an unprecedented increase in 2023. HAdV-C strains, including types C1, C2, and C5, were annually detected in pathogen surveillance in Osaka. HAdV-B3 was not detected for 2 years and 9 months from March 2020, and the number of detections increased from July 2023. In total, HAdV-B3 was the most frequently detected (27 of 52 strains), and genetic analysis of its hexon hypervariable regions showed that, except for one strain, the HAdV-B3 strains identified after 2022 had different amino acid substitutions compared to those identified in 2019 and 2020. These results suggest that the PCF epidemic in 2023 was predominantly caused by variant strains of HAdV-B3, and children who have not acquired immunity against HAdV-B3 between 2020 and 2022 were thought to be infected. The impact of COVID-19 on the prevalence of HAdV infections needs to be continuously evaluated through surveillance.

Chronic hepatitis C is a serious condition with relevant public health implications. In Portugal, the prevalence of detectable HCV antibodies is about 0,54%, with higher values in risk groups. Compared to the general population, the prevalence of HCV infection is higher in individuals with psychiatric disorders. There are no studies reporting the prevalence of HCV antibodies in Portuguese psychiatric patients, or in patients with substance use disorders.We carried an observational, prospective study during a period of one year, for patients followed at the Dual Pathology Outpatient and Inpatient Unity of the Coimbra Hospital and University Center, and patients were tested for HCV antibodies. Of 149 patients, 17.4% had positive HCV antibodies and 7.38% had detectable HCV RNA. Patients with confirmed CHC were mostly male inpatients, aged 50 to 59 years, and reported unprotected sex with more than one concurrent partner in the previous six months; their main psychiatric diagnosis was “Disorders due to use of multiple specified psychoactive substances, including medications”.This study reports a very high prevalence of positive HCV antibodies and confirmed CHC in patients followed in the Dual Pathology Outpatient and Inpatient Unity. This prevalence is higher than in general Portuguese population.

We report the isolation of Helicobacter cholecystus from a positive blood culture from a 58-year-old man in China who had bacteremia and acute cholecystitis. The patient’s condition improved after symptomatic support treatment and subtotal cholecystectomy. This finding suggests that H. cholecystus should be considered as potential human pathogens.

The accurate identification of individuals without prior infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is pivotal for seroepidemiological research and vaccine trials. Because of widespread COVID-19 vaccination, the anti-nucleocapsid antibody continues to serve as a valuable marker for individuals without a history of COVID-19. This study aimed to comprehensively assess anti-nucleocapsid antibody positivity using diverse commercial and in-house immunoassays among individuals who contracted COVID-19 more than 3 years ago. We enrolled 44 participants with laboratory-confirmed COVID-19 between January and May 2020 from Seoul National University Hospital and its community treatment centers. The results showed anti-nucleocapsid antibody positivities ranged from 45.5% to 87.9% depending upon the immunoassay used. The study highlights the importance of considering the limited anti-nucleocapsid antibody positivity in participants with a distant COVID-19 history in seroepidemiological or vaccine research.

In Japan, based on the National Epidemiological Surveillance of Infectious Diseases (NESID) Program, influenza cases from ~5,000 sentinel sites are monitored weekly as part of influenza surveillance (as number of influenza cases/sentinel site). One limitation is that the number of influenza tests conducted is not reported. Separately, the National Hospital Organization (NHO), with ~140 hospitals, routinely publishes three indicators: number of influenza tests, influenza-positive case counts, and test positivity. We used NESID and NHO data from April 2011 to June 2022 to assess the usefulness of multiple indicators to monitor influenza activity. Temporal trends of the NHO and NESID indicators were similar, and NHO indicator levels well-correlated with those of the NESID indicator. Influenza positivity in the NHO data, however, showed an earlier rise and peak time compared to the NESID indicator. Importantly, through the non-epidemic summer periods and the coronavirus disease 2019 pandemic, a sizable number of influenza tests continued to be done at NHO hospitals, with results showing considerably low case counts and test positivity. These data show that a relatively small number of sentinel sites is sufficient to monitor influenza activity nationally, and, that utilizing multiple indicators can increase our confidence in situational awareness and data interpretations.

The administration of high-dose clindamycin (CLI) along with penicillin is recommended for the treatment of streptococcal toxic shock syndrome (STSS). However, CLI-resistant strains have been identified worldwide. Firstly, in this study, some CLI-resistant strains showed increased extracellular activities of the NAD- glycohydrolase (NADase) exotoxin after CLI treatment. This result supported our previous conclusion that not only CLI-susceptible but also CLI-resistant S. pyogenes strains show the CLI-dependent NADase induction. Secondary, using the 13 types of two- component-sensor knockout strains derived from a CLI-susceptible strain 1529 that has the CLI-dependent NADase induction phenotype, we investigated the mechanism of action. Among the knockout strains, only 1529ΔcovS lost the phenotype. In addition, 1529ΔspeB, 1529Δmga, and 1529Δrgg retained the CLI-dependent NADase induction phenotype. These results suggest that CovS is related to the phenotype in SpeB independent manner.

The Japanese guidelines for the management of Clostridioides difficile infection (CDI) recommend metronidazole (MNZ) for non-severe cases and vancomycin (VCM) for severe cases. Here, we investigated the use of CDI antimicrobials and evaluated their clinical efficacy in four severity classifications and the validity of these classifications. A retrospective chart review was conducted on 137 inpatients with an initial positive C. difficile toxin test and initiation of CDI antimicrobials between April 2015 and March 2019. For the clinical efficacy analysis of the CDI antimicrobials and validation of the severity classifications, patients treated with VCM or oral MNZ were included. The endpoints were CDI recurrence rate, 30-day mortality rate, and diarrhea cure rate. No significant differences were found between the VCM and oral MNZ groups regarding the CDI recurrence rate (10.4% vs. 12.7%, p = 0.707), 30-day mortality rate (12.5% vs. 5.6%, p = 0.162), and diarrhea cure rate (61.9% vs. 72.7%, p = 0.238), regardless of the severity. Treatment with oral MNZ for non-severe cases was promising, confirming the usefulness of treatment according to Japanese guidelines. Further investigation of the clinical efficacy of oral MNZ in patients with first-episode CDI and evaluation of the preferable severity classification are warranted.

The patient was a 22-year-old woman with no comorbidities who was transferred to our hospital due to cardiac arrest. Treatment enabled return to spontaneous circulation in the patient before arriving at the hospital. At the hospital, the patient’s vital signs were unstable. Vasopressors and hyperhydration therapy were administered. Computed Tomography (CT) showed no remarkable change that caused the cardiac arrest. Antibiotics were prescribed after a blood culture exam. The patient was admitted to the ICU. In the ICU, the high-capacity vasopressors, hyperhydration therapy and transfusion of fresh frozen plasma were continued. Two hours after examining the blood culture, the results remained positive. Gram staining revealed Streptococcus, and the antibiotics were switched to penicillin G potassium, clindamycin and immunoglobulin was added. Hyperhydration therapy caused respiratory failure. Ten hours after admission to the ICU, extracorporeal membrane oxygenation was introduced, but the patient’s general status did not improve. The patient died at 40 hours after admission. Blood culture results proved Streptococcus pyogenes; T and M serotypes were unclassifiable. The emm genotype was emm22. Regarding fever toxin genes, speA and speB were positive, and speC was negative. Among CsrS, CsrR and Rgg amino acid sequences, mutations in CsrS were detected.