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Rapid diagnostic tests (RDTs) significantly impact disease treatment strategy. In Japan, information on the use of RDTs for patients with COVID-19 is limited. Here, we aimed to investigate the RDT implementation rate, pathogen detection rate, and clinical characteristics of patients positive for other pathogens by using COVIREGIJP, a national registry of hospitalized patients with COVID-19.A total of 42,309 COVID-19 patients were included. For immunochromatographic testing, influenza was the most common (n = 2881 [6.8%]), followed by Mycoplasma pneumoniae (n = 2129 [5%]) and group A streptococcus (GAS) (n = 372 [0.9%]). Urine antigen testing was performed for 5524 (13.1%) patients for S. pneumoniae and for 5326 patients (12.6%) for L. pneumophila.The completion rate of M. pneumonia loop-mediated isothermal amplification (LAMP) testing was low (n = 97 [0.2%]). FilmArray RP was performed in 372 (0.9%) patients; 1.2% (36/2881) of patients were positive for influenza, 0.9% (2/223) for the respiratory syncytial virus (RSV), 9.6% (205/2129) for M. pneumoniae, and 7.3% (27/372) for GAS. The positivity rate for urine antigen testing was 3.3% (183/5524) for S. pneumoniae and 0.2% (13/5326) for L. pneumophila. The positivity rate for LAMP test was 5.2% (5/97) for M. pneumoniae. Five of 372 patients (1.3%) had positive FilmArray RP, with human enterovirus being the most frequently detected (1.3%, 5/ 372).The characteristics of patients with and without RDTs submission and positive and negative results differed for each pathogen. RDTs remain an important diagnostic tool in patients with COVID-19 in whom coinfection with other pathogens needs to be tested based on clinical evaluation.

Anterior nasal sampling (AN) might be more convenient for patients than NP sampling to diagnose coronavirus disease. This study investigated the feasibility of rapid antigen tests for AN sampling, and the factors affecting the test accuracy.This single-center prospective study evaluated one qualitative (ESP) and two quantitative (LUMI and LUMI-P) rapid antigen tests using AN and NP swabs. Symptomatic patients aged 20 years or older, who were considered eligible for reverse-transcription quantitative polymerase chain reaction using NP samples within 9 days of onset were recruited. Sensitivity, specificity, and positive and negative concordance rates between AN and NP samples were assessed for the rapid antigen tests. We investigated the characteristics that affected the concordance between AN and NP sampling results.A total of 128 cases were recruited, including 28 positive samples and 96 negative samples. The sensitivity and specificity of AN samples using ESP were 0.81 and 1.00, while those of NP samples were 0.94 and 1.00. The sensitivity of AN and NP samples was 0.91 and 0.97, respectively, and specificity was 1.00, for both LUMI and LUMI-P. The positive concordance rates of AN to NP sampling were 0.87, 0.94, and 0.85 for ESP, LUMI, and LUMI-P, respectively. No factor had a significant effect on the concordance between the sampling methods.ESP, LUMI, and LUMI-P showed practical diagnostic accuracy for AN sampling compared to NP sampling. There was no significant factor affecting the concordance between AN and NP sampling for these rapid antigen tests.

Information regarding effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant strains on clinical manifestations and outcomes of coronavirus disease 2019 (COVID-19) in pregnant women is limited.A retrospective observational study was conducted using the data from the nationwide COVID-19 registry in Japan. We identified pregnant patients with symptomatic COVID-19 hospitalized during the study period. The Delta and Omicron variants of concern (VOC) predominant periods were defined as August 1 to December 31, 2021 and January 1 to May 31, 2022, respectively. Clinical characteristics were compared between the patients in the Delta and Omicron VOC periods. In addition, logistic regression analysis was performed to identify risk factors for developing moderate-to-severe COVID-19.During the study period, 310 symptomatic COVID-19 cases of pregnant women were identified; 111 and 199 patients were hospitalized during the Delta and Omicron VOC periods, respectively. Runny nose and sore throat were more common, and fatigue, dysgeusia, and olfactory dysfunction were less common manifestations observed in the Omicron VOC period. In the multivariable logistic regression analysis, onset during the later stage of pregnancy (OR: 2.08 [1.24-3.71]) and onset during the Delta VOC period (OR: 2.25 [1.08-4.90]) were independently associated with moderate-to-severe COVID-19, whereas two doses of SARS-CoV-2 vaccine were protective against developing moderate-to-severe COVID-19 (OR: 0.34 [0.13-0.84]).Clinical manifestations of COVID-19 in pregnant women differed between the Delta and Omicron VOC periods. SARS-CoV-2 vaccination was still effective in preventing severe COVID-19 throughout the Delta and Omicron VOC periods.

Information regarding the clinical manifestations and outcomes of coronavirus disease 2019 (COVID-19) in children under the Omicron variant predominant period is still limited.A nationwide retrospective cohort study was conducted. Pediatric COVID-19 patients (18 years of age) hospitalized between August 1, 2021 and March 31, 2022 were enrolled. Epidemiological and clinical characteristics between the Delta variant predominant period (August 1 to December 31, 2021) and the Omicron variant predominant period (January 1 to March 31, 2022) were compared.During the study period, 458 cases in the Delta predominant period and 389 cases in the Omicron predominant period were identified. Median age was younger (6.0 vs. 8.0 years, P = 0.004) and underlying diseases were more common (n = 65, 16.7% vs. n = 53, 11.6%) in the Omicron predominant period than those in the Delta variant predominant era. For clinical manifestations, fever ≥38.0 °C at 2 to13 years old, sore throat at ≥ 13 years, and seizures at 2 to13 years old were more commonly observed, and dysgeusia and olfactory dysfunction at ≥ 6 years old were less commonly observed in the Omicron variant predominant period. The number of patients requiring noninvasive oxygen support was higher in the Omicron predominant period than that in the Delta predominant period; however, intensive care unit admission rates were similar and no patients died in both periods.In the Omicron variant predominant period, more pediatric COVID-19 patients experienced fever and seizures, although the overall outcomes were still favorable.

Reimbursements for pharmacist interventions and infectious disease teams have recently been introduced in Japan. Arbekacin (ABK) is used to treat pneumonia and sepsis caused by methicillin-resistant Staphylococcus aureus, and therapeutic drug monitoring (TDM) is recommended. This study aimed to clarify the trend in TDM implementation for ABK over time and the factors associated with TDM implementation using a claims database.Data of patients aged ≥15 years who received ABK for ≥3 consecutive days between 2010 and 2019 were extracted from a large Japanese medical claims database. The proportion of reimbursements claimed for TDM, pharmacist interventions, and the setup of infectious disease teams for each year were calculated. The factors associated with TDM implementation were identified using multivariate logistic regression analysis.The proportion of TDM implementation for ABK increased by 9.1% from 2010 to 2019, but it remained less than 40% throughout this period. The proportion of TDM implementation was higher in patients who claimed reimbursements for pharmacist interventions than in patients who did not. Logistic regression analysis showed that the stationing of pharmacists in wards and long-term ABK treatment were significantly associated with TDM implementation.From 2010 to 2019, the proportion of TDM implementation for ABK was significantly low. Moreover, the factors associated with TDM implementation were clarified. An environment wherein pharmacists can help implement TDM for patients receiving ABK would be beneficial.

Influenza remains a clinically heavy burden worldwide. It is well known that some populations are at high risk of complications from influenza, whereas, even previously healthy people might suffer from severe influenza. The objective of this study was to clarify clinical manifestations of hospitalized patients without risk factors infected with influenza.The clinical data for patients who were severely ill with influenza, and required hospitalization were gathered and analyzed between November 2014 and August 2020 (6 influenza seasons) using an internet-surveillance system. Among them, the patients who had no risk factors of complications from influenza were extracted.Finally, a total of 91 patients (9.0% of all influenza-related hospitalizations) without risk factors were analyzed. The no risk group was younger than the risk group, though other significant differences of clinical characteristics were not recognized between the groups. Pneumonia was the most common cause of hospitalization in the no risk group, and primary influenza viral pneumonia was the most common pneumonia. Antiviral drugs were administered in 96.7% of the no-risk group, and artificial ventilation was performed in 18.7%. In-hospital death was recorded for 3 patients without risk factors.Severe complications of influenza which required hospitalization may occur in a certain degree of patients with no risk factors. Efforts are needed to diagnose and treat influenza appropriately even in previously healthy younger patients. Continuous nationwide surveillance will be required to clarify risk factors for severe influenza even in previously healthy younger patients. (UMIN000015989).

Introduction In response to global outbreaks of infectious diseases, the need for support from organizations such as the World Health Organization Global Outbreak Alert and Response Network (GOARN) is increasing. Identifying the obstacles and support needs for applicants could increase GOARN deployments from Japan. Methods This cross-sectional study involved a web-based, self-administered questionnaire survey targeting Japanese participants in the GOARN Tier 1.5 training workshop, held in Tokyo in December 2019. Results All 47 Japanese participants in the workshop responded to the survey. Most responders were male and in their 30s and 40s. Participants specialized in case management (42.6%), infection prevention and control (25.6%), epidemiology and surveillance (19.1%). Only two participants (4.6%) had experienced a GOARN deployment. Their motivations for joining the GOARN training workshop were “Desire to be part of an international emerging infectious disease response team” (44.6%), “Interest in making an international contribution” (19.1%), and “Interest in working for the Japanese government in the field of international infectious diseases” (14.9%). Obstacles to GOARN deployments were “Making time for deployments” (45.7%) and “Lack of required professional skills and knowledge” (40.4%). The support needs for GOARN deployments constituted “Periodic simulation training” (51.1%), “Financial support during deployments” (44.7%), and “Technical support for deployments” (40.4%). Conclusions Our study revealed the obstacles and support needs of Japanese candidates for GOARN deployment. Making time and upskilling for GOARN deployment were the main obstacles. More practical training (like GOARN Tier 2.0) with other supports are needed. The national framework is desirable to realize these supports.

Introduction The automated quantitative antigen test (QAT), which detects severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is suitable for mass screening. However, its diagnostic capability differentiated by time from onset and potential contribution to infectivity assessment have not been fully investigated. Methods A retrospective, observational study using nasopharyngeal swab specimens from coronavirus disease (COVID-19) inpatients was conducted using LumipulseⓇ SARS-CoV-2 antigen test. Diagnostic accuracy was examined for the early (up to 10 days after onset) and late (over 10 days after onset) stages. Time-course QAT changes and reverse‐transcription quantitative polymerase chain reaction tests results were displayed as locally estimated scatterplot smoothing curve, and receiver operating characteristic curve (ROC) analysis was used to determine the appropriate cutoff value for differentiating the early and late stages. Results We obtained 100 specimens from 68 COVID-19 patients, including 51 early-stage and 49 late-stage specimens. QAT sensitivity and specificity were 0.82 (0.72–0.90) and 0.95 (0.75–0.99) for all periods, 0.93 (0.82–0.98) and 1.00 (0.39–1.00) for the early stage, and 0.66 (0.48–0.82) and 0.93 (0.69–0.99) for the late stage, respectively. The ROC analysis indicated an ideal cutoff value of 6.93 pg/mL for distinguishing early-from late-stage specimens. The sensitivity, specificity, positive predictive value, and negative predictive value for predicting the late stage were 0.76 (0.61–0.87), 0.76 (0.63–0.87), 0.76 (0.61–0.87), and 0.76 (0.63–0.87). Conclusions QAT has favorable diagnostic accuracy in the early COVID-19 stages. In addition, an appropriate cutoff point can potentially facilitate rapid identification of noncontagious patients.

Introduction Many articles have reported that the coronavirus disease 2019 (COVID-19) causes coagulation abnormalities and pulmonary thrombosis, contributing to a poorer prognosis. The study aimed to evaluate whether pre-admission anticoagulation and antiplatelet therapy prevented severe COVID-19 illness or not. Materials and methods We conducted a study to determine whether taking antiplatelet or anticoagulation agents before admission affected the severity on admission using a large nationwide cohort of hospitalized COVID-19 patients in Japan. We analyzed a large nationwide cohort of hospitalized COVID-19 patients in Japan from February 9 to July 31, 2020. Results and conclusion A total of 4265 patients from 342 facilities in Japan were included. Their use was associated with a slight reduction in the disease severity on admission in a propensity score-matched analysis which controlled for underlying diseases. However, this difference was not statistically significant.

We report the case of a 67-year-old woman with disseminated Streptococcus anginosus invasive infection. Even under a maximal dose of susceptible antibiotics, her condition was complicated by pulmonary septic emboli and intracranial subdural abscess. Effective antibiotics and emergent surgical drainage were performed, but the sequelae of aphasia and hemiplegia remained. Underlying immunocompromised conditions of diabetes mellitus and monoclonal gammopathy of unknown significance might partially affect the clinical course of invasive S. anginosus infection. Once the infection becomes invasive, it can be refractory and difficult to treat. Clinicians should acknowledge the characteristics of invasive S. anginosus infection.

INTRODUCTION: Among patients with coronavirus disease 2019 (COVID-19), the factors that affect anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody production remain unclear. This study aimed to identify such factors among patients convalescing from COVID-19. METHODS: This study comprised patients who had been diagnosed with COVID-19 between January 1 and June 30, 2020 and gave consent for anti-SARS-CoV-2 spike protein antibody measurement using enzyme-linked immunosorbent assay during their acute and/or convalescent phases. Factors related to elevated antibody titers and the relationship between the days from disease onset and the development of antibody titers were assessed. RESULTS: A total of 84 participants enrolled in the study. Nineteen participants had antibody titers measured during the convalescent phase only, and 65 participants had antibody titers measured during the acute and convalescent phases. The antibody titers peaked in weeks 5 and 6. The stepwise multivariate log-normal analysis revealed that male sex (P = 0.04), diabetes mellitus (P = 0.03), and high C-reactive protein levels during the disease course (P

We previously showed the trend of antimicrobial use (AMU) for Clostridioides (Clostridium) difficile infection (CDI) using sales data. However, the details of the prescribing medical institutions and regional characteristics are unknown. Therefore, the purpose of this study was to clarify the details of the medical institutions where antibiotics for CDI were prescribed, and evaluate the AMU for CDI and the regional characteristics.Antibiotics for CDI, including oral vancomycin (VCM), oral metronidazole (MNZ), and intravenous (IV) MNZ, were collected from the National Database of Health Insurance Claims and Specific Health Checkups (NDB) between 2013 and 2016. The PID (patients/1000 inhabitants/day) was used as an evaluation index for AMU. The PID was calculated using the claim types: inpatient, outpatient, dental, and pharmacy. The PID of each prefecture was calculated for inpatient claims in 2016.The AMU of oral VCM and IV MNZ were observed mainly in the inpatient claims. For oral MNZ, the total AMU in the outpatient and pharmacy claims accounted for approximately 80% per year throughout the study period. For inpatient claims of each prefecture in 2016, the PID of the antibiotics used for CDIs was approximately 3.5 times the difference between the highest and lowest prefectures.The AMU for CDI that takes into account the purpose of use was clarified by using the information of the prescribed medical institutions that were included in the NDB. Oral MNZ was used frequently in outpatients, and attention should be paid to the acquisition of resistance.

Introduction Influenza remains a clinically heavy burden worldwide. The objective of this study was to clarify clinical manifestations of severely ill patients infected with influenza. Methods The clinical data for patients who were severely ill with influenza, and required hospitalization were gathered and analyzed between November 2014 and August 2019 (5 influenza seasons) using an internet-surveillance system. Results A total of 924 patients were enrolled and analyzed. The median age was 78 years (IQR, 67–84), and the patients in the 2015–2016 season were significantly younger than those in other seasons. Pneumonia was the most common disease indicated as a cause for hospitalization, followed by a poor general condition and exacerbation of underlying respiratory diseases. Antiviral drugs were administered in 97.0% of the patients with peramivir being the most-frequently use antiviral. In-hospital death was recorded for 44 patients (4.8%). Multivariate analysis indicated that nursing home resident (OR: 6.554) and obesity (OR: 24.343) were independent predictors of in-hospital mortality. Conclusions Complications of influenza infection remain a heavy burden especially among the elderly. Continuous nationwide surveillance will be required to grasp the actual situation of influenza epidemics. (UMIN000015989).

The aim of this study was to describe the clinical and radiological findings of COVID-19 patients with “silent hypoxia,” who had no dyspnea on admission even though their oximetry saturation was less than 94%. This retrospective cohort study included all COVID-19 patients (n = 270) at a large tertiary care hospital between January 31 and August 31, 2020. Clinical and radiological characteristics of patients who met our criteria of “silent hypoxia”, which included those who reported no dyspnea even though oximetry saturation was

Introduction Traveler's diarrhea (TD) is the most common illness among people traveling from resource-rich regions to resource-limited regions, although the precise microbial etiology is unclear in many cases. Methods Stool specimens were prospectively collected from 106 consecutive patients with TD and 16 healthy controls without TD, and were tested using both the FilmArray gastrointestinal panel (BioFire Diagnostics) and conventional stool cultures. Results The 106 patients had traveled to Southeast Asia (55 cases), South Asia (22 cases), Africa (11 cases), and East Asia (7 cases). Among the 106 specimens, 95 specimens (89.6%) were positive for pathogens during the FilmArray testing. The FilmArray testing also identified multiple pathogens in 75.8% of the specimens from positive cases. Conventional stool cultures only detected pathogens in 23.6% of the specimens. Conclusion The FilmArray gastrointestinal panel significantly improved the detection of enteropathogens and allowed for a rapid assessment of the TD's etiology. In addition, conventional stool cultures are likely to underestimate co-infections with multiple infectious pathogens.

Introduction A large number of antibiotics are used for the treatment of uncomplicated cystitis owing to its high morbidity. As the administration of antibiotics for uncomplicated cystitis may be considered an example of inappropriate use, outpatient antimicrobial stewardship for this condition is important. We evaluated the current pharmacoepidemiology trends for the treatment of uncomplicated cystitis in Japan to predict stewardship strategies. Methods This descriptive observational study analyzed data from an anonymized claims database of employees and their family members covered by the employer’s health insurance. We identified female outpatients diagnosed with acute cystitis (ICD-10 code N300) aged ≥15 years and extracted oral antibiotic prescription records between 2013 and 2016. We excluded prescriptions for >7 days. Results The most prescribed antibiotic category was fluoroquinolones (52.67%), followed by cephalosporins and penems (40.63%). Third-generation cephalosporins accounted for 90.91% of cephalosporin and penem prescriptions. The most common duration of antibiotic prescription was 5 days, except for first-generation cephalosporins, penem (7 days) and sulfamethoxazole and trimethoprim (3 days). Conclusion Fluoroquinolones and third-generation cephalosporins were prescribed to most uncomplicated cystitis cases in Japan. Although the lack of alternatives to quinolones and beta-lactams in Japan is an obstacle for antimicrobial stewardship for uncomplicated cystitis, promoting accurate diagnoses and establishing alternatives available in the Japanese market are important. Shortening the treatment duration is also an important strategy. Further research is needed on local antimicrobial resistance patterns to determine a fixed treatment strategy for uncomplicated cystitis.

S. pseudintermedius, recently identified as a novel Staphylococcus, causes a rare zoonotic infection that can be transmitted from dogs to humans. A 41-year-old man with atopic dermatitis receiving central parenteral nutrition through a totally implantable venous access port (TIVAP) after surgery for pseudomyxoma peritonei visited our outpatient clinic with a 2-day history of fever. The four strains isolated from the blood cultures from the TIVAP, dog's mouth, dog's nose, and dog's skin were all identified as S. pseudintermedius by partial heat shock protein (hsp60) gene sequencing. Initially, antibiotic-lock therapy with vancomycin (5 mg/mL in normal saline) through the catheter was administered concurrently with intravenous therapy. However, 52 days after the first discharge, he came back with a recurrent TIVAP infection with S. pseudintermedius bacteremia. He was successfully treated with intravenous antibiotic therapy after port removal and had no recurrence for 6 months without contact with the dog. The isolated strains were resistant to fluoroquinolone, which was consistent with trends in veterinary medicine in Japan. This case report raises awareness on S. pseudintermedius infections transmitted from domesticated dogs to patients with any implantable device, and the emerging resistance of S. pseudintermedius to current antibiotics.

Background Healthcare-associated infection (HAI) surveillance is useful for improved infection control. To understand the current HAI surveillance systems (HAISS) trend globally, a scoping review was performed. Materials and methods The search strategy included academic literature review, Google search, and questionnaires by the Embassies of Japan (registration number: UMIN000036035). Eighty-two high and 56 upper-middle income countries defined by country income classification for the World Bank were targeted. The following information was reviewed: name of the system, official website, languages used in the official website, foundation year, operating body, survey type (prevalence or incidence), reporting periodicity, mode of participation (mandatory or voluntary), targeted medical facilities, targeted HAIs and definitions, targeted antimicrobial resistant pathogens, and parameters. Online accessibility of the official websites of the SS was assessed through Google search. Results and conclusion Forty-two (30.4%) countries (35 [42.7%] high and 7 [12.5%] upper-middle income countries) had national HAISS. Most systems operated on a voluntary basis, monitored HAI incidence, and used the Center for Disease Control and Prevention definitions. Methicillin-resistant Staphylococcus aureus, surgical site infection, and catheter-related blood stream infection were most commonly monitored. Surveillance for device-associated infections was implemented mainly in intensive care units. Thirty-five countries had at least one official website on their systems, while 7 (20.0%) were identified in the top 30 Google search hits, in English. Approximately half of the academic articles identified through PubMed were from three English-speaking countries. The feasibility and benefits of standardization of the HAI surveillance criteria and efficient feedback methods are future considerations.

We report a case of a 27-year old woman with persistent fever and pancytopenia who had multiple episodes of a hemophagocytic lymphohistiocytosis (HLH) like condition. The criterion for HLH was satisfied; primary cytomegalovirus (CMV) infection was identified as the cause. Further examination revealed a GATA binding protein 2 mutation. Reports of GATAs deficiency presenting with HLH after primary CMV infection is very limited. As early recognition and diagnosis will improve patients' outcomes, internists and infectious disease specialists should be aware of this disease.

Introduction: The post-COVID condition has become a social concern. Although the patient characteristics associated with the development of this condition are partially known, those associated with its persistence have not been identified.Methods: We conducted a cross-sectional questionnaire-based survey among patients who had recovered from COVID-19 and visited the National Center for Global Health and Medicine between February 2021 and March 2021. Demographic and clinical data, and data regarding the presence and duration of post-COVID conditions were obtained. We identified factors associated with the development and persistence of post-COVID conditions using multivariate logistic and linear regression analyses, respectively. Results: We analyzed 457 of 526 responses (response rate, 86.9%). The median patient age was 47 years. Of these, 378 patients (84.4%) had mild disease in the acute phase. The number of patients with symptoms at 6 and 12 months after onset or diagnosis was 120 (26.3%) and 40 (8.8%), respectively. Women were at risk of developing fatigue (odds ratio [OR]: 2.03, 95% confidence interval [CI]: 1.31-3.14), dysosmia (OR: 1.91, 95%CI: 1.24-2.93), dysgeusia (OR: 1.56, 95%CI: 1.02-2.39), hair loss (OR: 3.00, 95%CI: 1.77-5.09), and persistence of any symptoms (coefficient: 38.0, 95%CI: 13.3-62.8). Younger age and low body mass index were factors for developing dysosmia (OR: 0.96, 95%CI: 0.94-0.98 and OR: 0.94, 95%CI: 0.89-0.99, respectively) and dysgeusia (OR: 0.98, 95%CI: 0.96-1.00 and OR: 0.93, 95%CI: 0.88-0.98, respectively).Conclusion: We identified factors involved in the development and persistence of post-COVID conditions. Many patients, even those with mild conditions, experience long-term residual symptoms.

BackgroundWe aimed to assess the impact of regional heterogeneity on the severity of COVID-19 in Japan.MethodsWe included 27,865 cases registered between January 2020 and February 2021 in the COVID-19 Registry of Japan to examine the relationship between the National Early Warning Score (NEWS) of COVID-19 patients on the day of admission and the prefecture where the patients live. A hierarchical Bayesian model was used to examine the random effect of each prefecture in addition to the patients’ backgrounds. In addition, we compared the results of two models; one model included the number of beds secured for COVID-19 patients in each prefecture as one of the fixed effects, and the other model did not.ResultsThe results indicated that the prefecture had a substantial impact on the severity of COVID-19 on admission. Even when considering the effect of the number of beds separately, the heterogeneity caused by the random effect of each prefecture affected the severity of the case on admission.ConclusionsOur analysis revealed a possible association between regional heterogeneity and increased/decreased risk of severe COVID-19 infection on admission. This heterogeneity was derived not only from the number of beds secured in each prefecture but also from other factors.

The Omicron variant of severe acute respiratory syndrome coronavirus 2 has multiple amino acid mutations in its spike proteins, which may allow it to evade immunity elicited by vaccination. We examined the neutralising activity and S1-IgG titres in patients with breakthrough infections caused by the Omicron variant after two doses of vaccination. We found that neutralising activity was significantly lower for the Omicron variant than for the Wuhan strain. Two doses of vaccination might not induce sufficient neutralising activity for the Omicron variant.

BackgroundNo epidemiological data on post coronavirus disease (COVID-19) condition due to Omicron variant has been reported yet.MethodsThis was as a single-center, cross-sectional study, that interviewed via telephone the patients who recovered from Omicron COVID-19 infection (Omicron group), and surveyed via self-reporting questionnaire those patients infected with other strains (control group). Data on patients’ characteristics, information regarding the acute-phase COVID-19, as well as presence and duration of COVID-19-related symptoms were obtained. Post COVID-19 condition in this study was defined as a symptom that lasted at least 2 months within 3 months since the onset of COVID-19. We investigated and compared the prevalence of post COVID-19 condition in both groups after performing propensity score matching.ResultsWe conducted interviews for 53 out of 128 patients with Omicron, and obtained 502 responses in the control group. After matching, 18 patients each in Omicron and control group had improved covariate balance of the older adult, female sex, obese patients, and vaccination status. There were no significant differences in the prevalence of each post-acute COVID-19 symptoms between the two groups. The numbers of patients with at least one post-acute COVID-19 symptom in the Omicron and the control group were 1 (5.6%) and 10 (55.6%) (p=0.003), respectively.ConclusionThe prevalence of post Omicron COVID-19 conditions was less than that of the other strains. Further research with more participants is needed to investigate the precise epidemiology of post COVID-19 condition of Omicron, and its impact on health-related quality of life and social productivity.

We report three cases of tick-associated rash illness (TARI) in Japan that presented with erythema migrans (EM) after a tick bite. Although EM is considered to be a characteristic finding of Lyme disease, EM can occur even if patient is not affected by Lyme disease and if it is bitten by a tick. In Japan, the vector of Lyme disease pathogens are not distributed in most areas, and patients with EM are unlikely to have Lyme disease. We aim to raise TARI awareness among physicians.

Objectives To alleviate the overflow of coronavirus disease 2019 (COVID-19) patients in hospitals, less invasive and simple criteria are required to triage the patients. We evaluated the relationship between COVID-19 severity and fatty liver on plain computed tomography (CT) scan performed on admission. Methods In this retrospective cohort study, we considered all COVID-19 patients at a large tertiary care hospital between January 31 and August 31, 2020. COVID-19 severity was categorized into severe (moderate and severe) and non-severe (asymptomatic and mild) groups, based on the Japanese National COVID-19 guidelines. Fatty liver was detected on plain CT scan. Multivariate logistic regression analysis was performed to evaluate factors associated with severe COVID-19. Results Of 222 patients (median age: 52 years), 3.2%, 58.1%, 20.7%, and 18.0% presented with asymptomatic, mild, moderate, and severe COVID-19, respectively. Although 59.9% had no fatty liver on plain CT, mild, moderate, and severe fatty liver occurred in 13.1%, 18.9%, and 8.1%, respectively. Age and presence of fatty liver were significantly associated with severe COVID-19. Conclusion Our study showed that fatty liver on plain CT scan on admission can become a risk factor for severe COVID-19. This finding may help clinicians to easily triage COVID-19 patients.

INTRODUCTION: We aimed to analyze the clinical characteristics and outcomes of immunosuppressed inpatients with coronavirus disease 2019 (COVID-19). METHODS: In this observational study, we utilized a large nationwide registry of hospitalized patients with COVID-19 in Japan. Patients' baseline characteristics and outcomes were compared according to the immunosuppressed states of the patients. The impact of different therapeutic agents on the clinical courses of the patients was evaluated. RESULTS: Data of 14,760 patients were included, and 887 (5.9%) were immunosuppressed. The immunosuppressed state of the patient resulted from solid tumor (43.3%, n = 384), chemotherapy within 3 months (15.6%, n = 138), collagen disease (16.9%, n = 150), use of immunosuppressive agents (16.0%, n = 142), and metastatic solid tumor (13.5%, n = 120). Immunosuppressed patients were older and had a higher severity of illness at admission and during hospitalization than non-immunosuppressed patients. The mortality rates for major diseases causing immunosuppression were as follows: solid tumor, 12.5% (48/384; P

Rapid antigen tests (RATs) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have advantages over viral culture in terms of cost and rapidity of testing, but they have low sensitivity. In addition, RATs tend to be negative from approximately 11 days after symptom onset. To determine whether the antigen-negative state indicates a lack of infectiousness, we assessed the association between viral culture and RAT results. Viral culture, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and rapid antigen testing were performed on stored nasopharyngeal samples with threshold cycle values

Introduction “Re-infection” with COVID-19 is a growing concern; re-infection cases have reported worldwide. However, the clinical characteristics of SARS-CoV-2 re-infection, including the levels and role of anti-SARS-CoV-2 Spike protein IgG antibodies and the half-maximal concentration (IC50) of neutralizing antibodies remain unknown. Methods Both the epidemiological and clinical information has been collected during two episodes of COVID-19 in a patient. Laboratory results, including RT-PCR, Ct values, anti-SARS-CoV-2 Spike protein IgG antibodies, and the IC50 of neutralizing antibodies levels were analyzed on the patient. Results The patient was a 58-year-old man who developed moderate COVID-19 pneumonia with oxygen demand (cannula 2 L/min) in the first episode. By day 30, he recuperated and was discharged after testing negative for SARS-CoV-2. After two and a half months, his three family members showed COVID-19 symptoms and tested positive for SARS-CoV-2. He tested positive for SARS-CoV-2 once again and was asymptomatic (the second episode). The IC50 of neutralizing antibodies against SARS-CoV-2 greatly increased from 50.0 μg/mL (after the first episode) to 14.8 μg/mL (after the second episode), and remained strongly reactive (20.1 μl/mL) after 47 days of the second episode. Conclusions Epidemiological, clinical, and serological analyses confirmed that the patient had re-infection instead of persistent viral shedding from first infection. Our results suggest that SARS-CoV-2 re-infection may manifest as asymptomatic with increased neutralizing antibody levels. Further studies such as the virus characteristics, immunology, and epidemiology on SARS-CoV-2 re-infection are needed.

Introduction Convalescent plasma transfusion (CPT), a potential therapy for coronavirus disease 2019 (COVID-19), requires strict quality control of the donor blood. Whether to confirm the disappearance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA (RNAemia) in convalescent donor blood or not is unclear. Reports recommending the proof of viral disappearance from the blood are controversial. Foreseeing CPT in treating COVID-19 patients in Japan, we investigated RNAemia in 100 convalescent donors with mild, moderate, and severe COVID-19. Methods Between April 30 and July 30, 2020, we measured RNAemia in the plasma samples of donors with resolved COVID-19. Data on patients’ demographics, comorbidities, pneumonia, treatment, and real-time polymerase chain reaction results for SARS-CoV-2 were collected. Date of onset of initial symptoms or date of positive testing (for asymptomatic patients) were self-reported by the patients. Disease severity was defined as: no, mild, moderate oxygen demand, or severe (requiring mechanical ventilation). Results Of 100 donors (58 males [58.0%]; median age, 47 [range 22–69] years) screened as of July 30, 2020, 77 (77.0%); 19 (19.0%); and 4 (4.0%) had mild, moderate, and severe disease, respectively. Median time between onset and testing was 68.5 (range, 21–167) days. SARS-CoV-2 RNA was not detected in any of the plasma samples. Conclusion RNAemia was not found in recovered COVID-19 patients at least 21, 27, and 57 days after the onset of mild, moderate, and severe symptoms. Our study may contribute to determining a suitable time for collecting convalescent plasma from COVID-19 patients and to future CPT use.

Introduction: In late January 2020, the Japanese government carried out three evacuations by aircraft from Wuhan, China, to avoid further cases of coronavirus disease 2019 (COVID-19) among Wuhan's Japanese residents. Evacuation by aircraft may be an effective countermeasure against outbreaks of infectious diseases, but evidence of its effect is scarce. This study estimated how many COVID-19 cases were prevented among the Japanese residents of Wuhan by the evacuation countermeasure. Methods: We constructed a SETAIR (susceptible-exposed-transitional-asymptomatic-infectious-recovered) model to capture the epidemic growth of COVID-19 cases in Wuhan to estimate the predicted number of COVID-19 cases among Wuhan's Japanese residents if evacuation had not occurred at the end of January. We used data on the number of COVID-19 cases confirmed in Hubei Province for the period Jan 20-Feb 16, 2020, and on the number of cases of Japanese residents who were evacuated by aircraft on Jan 29, 30, and 31. Results: Eleven imported COVID-19 cases were reported on Feb 1 from among the total 566 evacuees who returned to Japan. In the case of no evacuations being made, the cumulative number of COVID-19 cases among Wuhan's Japanese residents was estimated to reach 25 (95% CI [20,29]) on Feb 8 and 34 (95% CI [28,40]) on Feb 15. A 1-week delay in the evacuation might be led to 14 additional cases and a 2-week delay to 23 additional cases. Conclusions: Evacuation by aircraft can contribute substantially to reducing the number of infected cases in the initial stage of the outbreak. (C) 2020 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

We here report a case of coronavirus disease-19 (COVID-19) in Japan in which the initial throat swab polymerase chain reaction result was negative The possibility of false-negative results in the early phase of disease suggest reconsideration of the feasibility of a community or national infection control framework to prevent transmission. We recommend establishing an alternative feasible system, such as self-isolation by contact history in non-endemic community and by symptoms in endemic community, not relying on the PCR examination, to minimize this ongoing COVID-19 outbreak. Further rapid accumulation of knowledge including incubation period, clinical course and types of transmission is warranted to control this outbreak.

Melioidosis, an infectious disease with high mortality, caused by Burkholderia pseudomallei, is endemic in southeast Asia and northern Australia. In Indonesia, autochthonous cases have been rarely reported, with most cases being sporadic and occurring in travelers. Herein, we report a fatal case of neurological melioidosis in a traveler from Indonesia presenting with septic shock.

A 71-year-old Japanese man with travel history to the Vancouver Island, Canada was diagnosed the pulmonary and central nervous system infections caused by Cryptococcus gattii genotype VGIIa. This is the first imported case of Cryptococcus gattii genotype VGIIa infection from endemic area of North America to Japan. He was recovery with no residual neurological dysfunction by early resection of brain mass and antifungal therapy. Early surgical resection of cerebellar cryptococcoma may shorten the length of induction therapy with antifungal drugs.

Data on community-associated extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (CA-ESBLEC) infections in Japan are scarce. We compared the clinical and microbiological epidemiology of CA-ESBLEC infections with that of healthcare-associated-ESBLEC infections among 76 patients with ESBLEC infections. We identified a high prevalence (26%) of CA-ESBLEC infections in Japan; only a small proportion (15%) of patients with CA-ESBLEC infections had recent exposure to antibiotics.

Leptospirosis is one of the most common travel-related infections. We report 5 cases of travel-related leptospirosis who presented at our clinic between January 2008 and December 2013. Patients were included in the study if they presented with a clinical profile that was compatible with the disease within 21 days of their return from traveling, which were laboratory-diagnosed as leptospirosis by blood culture, rise in antibody titers in paired sera using the microscopic agglutination test (MAT), and/or DNA detection using flaB-nested PCR. Five leptospirosis cases were evaluated, all of which contracted the disease after exposure to fresh water in Southeast Asian countries. All of the cases had fevers, headaches, conjunctival injections, and relative bradycardia. The pertinent laboratory findings included elevated C-reactive protein levels, elevated creatinine levels, and sterile pyuria. All 5 cases had serum MAT titers that increased by ≥ 4 times in the interval between specimens taken during the acute phase and those taken during the convalescence phase, and leptospiral DNA was detected in plasma and/or urine specimens in 4 cases. Leptospira interrogans was isolated from one patient's blood sample. Patients were treated with penicillin G, minocycline, or doxycycline. One case was cured without antibiotics. A diagnosis of leptospirosis should be considered for febrile travelers who return from Southeast Asian countries to Japan after being exposed to freshwater while traveling.

We report a case of multidrug-resistant (MDR) Acinetobactor baumannii isolates obtained from a traveler returned from Brunei. Whole-genome sequencing analysis revealed that the isolates harbored blaOxA-23 and armA. The minimum inhibitory concentrations of antibiotics against the strain were as follows: imipenem, 32 μg/ml; meropenem, 32 μg/ml; ciprofloxacin, 16 μg/ml; amikacin, ≧ 1024 μg/ml; arbekacin, ≧ 1024 μg/ml; aztreonam, 64 μg/ml; colistin, 4 μg/ml. A. baumannii harboring both blaOxA-23 and armA is rarely reported in Japan, and, to the best of our knowledge, this is the second report of A. baumannii harboring both resistant genes in Japan.

The spread throughout Japan of antibiotic-resistance factors in multidrug-resistant (MDR) Pseudomonas aeruginosa isolates was investigated epidemiologically, using immunochromatographic assays specific for IMP-type metallo-β-lactamases (IMPs) and aminoglycoside 6'-N-acetyltransferase [AAC(6')]-Iae and -Ib. Three hundred MDR P. aeruginosa isolates were obtained during each of two years, 2011 and 2012, from 190 hospitals in 39 prefectures in Japan. The percentage of P. aeruginosa isolates producing IMPs, AAC(6')-Iae or AAC(6')-Ib increased significantly from 170/300 (56.7%) in 2011 to 230/300 (76.7%) in 2012, with 134/170 (78.8%) in 2011 and 179/230 (77.8%) in 2012 producing both IMP and either AAC(6')-Iae or AAC(6')-Ib. The MICs of antibiotics, including cephalosporins and carbapenems, were markedly higher for isolates that did than did not produce these resistance factors. These results indicated that MDR P. aeruginosa producing IMPs, AAC(6')-Iae or AAC(6')-Ib have spread throughout Japan and that these antibiotic-resistance factors are useful markers for monitoring MDR P. aeruginosa in Japan.

Arbekacin (ABK) was approved and widely used in Japan for treatment of patients infected with MRSA, and TDM was introduced in clinical practice. The Japanese Society of Chemotherapy and the Japanese Society of Therapeutic Drug Monitoring decided to develop a clinical practice guidelines for TDM of ABK for the following reasons. First, although the daily dose of 150e200 mg was approved in Japan, recent PK- PD studies revealed that higher serum concentration is required to achieve better clinical efficacy and several findings concerning the usefulness of higher dosage regimen have obtained recently. Second, although maximal concentrations that obtained immediately after the end of administration (Cmax )w as generally adopted, the serum concentration at 1 h after initiation of administration (peak serum con- centration (Cpeak)) proved to be more suitable as an efficacy indicator of aminoglycosides. Lastly, as ABK is approved only in Japan, no international practice guideline for TDM has not been available in ABK to date. This guideline evaluated the scientific data associated with serum ABK monitoring and provided rec- ommendations based on the available evidence. Potential limitations of this guideline, however, include the findings that few prospective clinical trials of TDM of ABK are available in the treatment of MRSA infections and that most of the published literature describes observational studies.