Contact tracing in the hospital setting during the omicron wave of the coronavirus disease 2019 pandemic: persons and periods of concern for nosocomial infection prevention and control.

This study evaluating the efficacy of coronavirus disease 2019 contact tracing in the hospital setting during the omicron variant era found a high incidence of nosocomial severe acute respiratory coronavirus virus 2 (SARS-CoV-2) transmission in outbreaks, especially among individuals having close contact with infected persons. Identifying close contacts and outbreaks is essential to prevent nosocomial SARS-CoV-2 transmission.

Urinary liver-type fatty acid-binding protein level as a prognostic indicator of acute kidney injury secondary to severe falciparum malaria.

Acute kidney injury (AKI) secondary to severe falciparum malaria possesses a high mortality rate; however, a prognostic marker of renal dysfunction has not yet been identified. Thus, we reported a case of a patient with AKI secondary to falciparum malaria who underwent hemodialysis and a renal biopsy due to prolonged renal dysfunction. The male patient, in his 50 s, presented to our hospital with vomiting, diarrhea, fever, and decreased level of consciousness. The Giemsa-stained peripheral blood film revealed approximately 5% parasitemia, and a rapid diagnostic test was positive for Plasmodium falciparum. He was diagnosed with severe falciparum malaria and was started on quinine hydrochloride. Hemodialysis was initiated due to the decreased urine output and fluid retention. Subsequently, he was weaned off hemodialysis. The histopathological analysis of a renal biopsy revealed interstitial fibrosis, tubular atrophy, and chronic inflammatory cell infiltration; thus, malarial nephropathy was diagnosed. Thereafter, his renal function stabilized, and he was discharged from the hospital. The urinary liver-type fatty acid-binding protein (L-FABP) level decreased before renal function improved. Our report highlighted that long-term follow-up is essential for severe AKI secondary to malaria. The urinary L-FABP level may be a useful prognostic indicator of AKI secondary to severe falciparum malaria.

Unfractionated Heparin Safety in COVID-19: Incidence and Risks of Bleeding Complications in Japan.

AIM: Several studies have shown the efficacy and safety of low-molecular-weight heparin use in coronavirus disease 2019 (COVID-19), but that of unfractionated heparin (UFH) has not been investigated. We investigated the prevalence of bleeding complications during UFH administration, its impact on mortality, and the risk factors of bleeding outcomes associated with UFH. METHODS: This retrospective cohort study was conducted at a single-center tertiary care hospital, including hospitalized patients with COVID-19. The primary outcomes were measured as the prevalence of bleeding complications during hospitalization, and the secondary outcomes were thromboembolic events and 60-day mortality rates. Logistic regression analysis and propensity score matching were used to assess risk factors for bleeding complications and their impact on mortality. RESULTS: Among 1035 included patients, 516 patients were treated with UFH. Twelve (2.3%) patients in the UFH group experienced major bleeding. The prevalence of major bleeding in patients treated with therapeutic-dose UFH was 9.2%. Logistic regression analysis showed that age ≥ 60 years (adjusted odds ratio [aOR], 3.89; 95% confidence interval [CI], 1.01-15.0; P＜.05) and COVID-19 severity (aOR, 35.9; 95% CI, 4.57-282; P ＜.05) were associated with major bleeding complications. After propensity score matching, 11 major and 11 non-major bleeding cases (including minor bleeding) were matched. The 60-day cumulative mortality rate between the two groups did not differ significantly (P=.13, log-rank test). CONCLUSIONS: The incidence of major bleeding in COVID-19 patients using therapeutic-dose UFH was relatively high. Critical COVID-19 and older age were risk factors for bleeding complications.

Trends of participants in convalescent plasma donation for COVID-19 in Japan as the pandemic evolved.

Background: We aimed to investigate chronological changes in the characteristics of participants in a coronavirus disease 2019 convalescent plasma donation study that may benefit optimal collection methods in the future. Methods: Data from a convalescent plasma donation study from April 30, 2020 to November 5, 2021 were collected and analyzed. After August 23, 2021, an interim analysis of factors linked to higher antibody titers led us to restrict our participant recruitment criteria to participants who were within 4 months of disease onset and to patients who were otherwise most likely to have sufficiently high antibody titers. Overall, 1299 samples from 1179 patients were analyzed. Results: Over the duration of the study, 35.9% of the samples were deemed eligible for convalescent plasma collection. The overall eligibility rate initially declined, dipping to <20% after one year. During this period, the proportion of enrolled samples from patients who had severe illness also declined, and the proportion of samples from participants who were >120 days post disease onset increased. After the addition of days from onset and vaccination status to our participant recruitment criteria, the eligibility rate improved significantly. Conclusions: As outbreaks of emerging infectious disease occur, it is desirable to construct and implement a scheme for convalescent plasma donation promptly and to monitor the eligibility rate over time. If it declines, promptly analyze and resolve the associated factors. Additionally, vaccine development and infection prevalence are likely to influence the effective recruitment of participants with high antibody titers.

Treatment with tecovirimat of the first two cases of monkeypox in Japan.

Outbreaks of monkeypox in Europe and North America have been reported since May 2022. At the end of July, we encountered the first two cases of monkeypox diagnosed in Japan. Case 1 was a white man who traveled to Spain where he had sexual intercourse with men. He presented to our hospital with fever, rash, and tiredness, and was diagnosed with monkeypox based on positive PCR test results from the skin lesions. He was admitted to our hospital, received tecovirimat 600 mg twice daily, and was discharged on day 15. Case 2 involved a Japanese man who visited us because of fatigue, muscle pain, headache, and oral ulcers. He was living in New York and traveled to Japan one day before presentation. He had experienced sexual intercourse with men four times during the previous month. The patient was diagnosed with monkeypox based on positive PCR results from the blood. He was admitted to our hospital, received tecovirimat 600 mg twice daily, and was discharged on day 14. These were the first two cases of monkeypox diagnosed in Japan. Based on their history and epidemiology, the viruses seem to have been imported from Europe and North America, respectively. After initiation of tecovirimat, both patients showed mild symptoms and immediate disappearance of viral DNA. The second case was notable for being diagnosed without skin rash. Our report suggests that tecovirimat could decrease the viral load rapidly, and that our prompt diagnosis contributed to the prevention of a monkeypox outbreak in Japan.

A case of prosthetic joint infection caused by Mycobacterium tuberculosis complicated secondary bacterial infection after knee joint replacement surgery.

Mycobacterium tuberculosis (M. tuberculosis) is a rare cause of prosthetic joint infection (PJI). Previous studies have reported that many cases of PJI caused by M. tuberculosis have no medical history of active tuberculosis (TB) or other localization, which contributes to diagnostic difficulties. Furthermore, owing to the limited number of studies on treatment, appropriate treatment strategies, such as the duration of anti-tuberculosis (anti-TB) drugs and surgical indications, remain unclear. We report a case of PJI caused by M. tuberculosis and secondary pyogenic arthritis caused by Staphylococcus aureus and Streptococcus dysgalactiae in a 67-year-old man after knee joint replacement surgery in Japan, which was a moderately endemic country until 2020 and a low endemic country since 2021. Although he had no past medical history or close contact with TB, he was diagnosed with PJI caused by M. tuberculosis, following the culture of a synovectomy specimen. He underwent two-stage surgery and was treated with anti-TB drugs for a total of 12 months and recovered without recurrence. Based on our case and previous studies, there are three points of clinical significance for PJI caused by M. tuberculosis. First, about one year of anti-TB drugs with two staged joint revision resulted in a good course of treatment. Second, surgical treatment might be considered in cases complicated by secondary bacterial infection. Third, because the diagnosis of PJI caused by M. tuberculosis is difficult, TB should be considered in the differential diagnosis of routine bacterial culture-negative PJI, especially in endemic areas.

A novel anticoagulation treatment protocol using unfractionated heparin for coronavirus disease 2019 patients in Japan, 2022.

Hypercoagulability, which can be induced by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) plays an important role in the pathogenesis of coronavirus disease 2019 (COVID-19). Although anticoagulation therapy is expected to decrease the incidence of thrombosis and mortality in COVID-19 patients, the optimal use of anticoagulation therapy has not been established, especially using unfractionated heparin (UFH). Herein, we suggest a new anticoagulation treatment protocol for the use of UFH in Japanese COVID-19 patients. This protocol considers the safety regarding UFH usage, to lower major bleeding events, and reflects the latest evidence and the current situation regarding anticoagulation therapy in Japan.

Case Report: Leptospirosis by Wild Rat Bite in Winter in Tokyo Metropolitan Area, Japan.

We report a case of leptospirosis in Tokyo in winter due to a rat bite, an uncommon cause of Leptospira infection. In Japan, many cases due to exposure to fresh water have been reported from domestic southwest islands in summer. However, a previous report on leptospirosis in Tokyo documented several cases occurring in winter. The main route of infection in the Tokyo metropolitan area during winter was attributed to the increased chance of direct rat exposure. Rapid and feasible diagnostic methods are needed to elucidate its epidemiology and provide prompt treatment.

Streptobacillus notomytis Bacteremia after Exposure to Rat Feces.

To determine the source of Streptobacillus notomytis bacteremia in a woman in Japan with signs of rat-bite fever, we examined rat feces from her home. After culture and PCR failed to identify the causative organism in the feces, next-generation sequencing detected Streptobacillus spp., illustrating this procedure's value for identifying causative environmental organisms.

Risk factors associated with asymptomatic hypoxemia among COVID-19 patients: a retrospective study using the nationwide Japanese registry, COVIREGI-JP.

Deaths of home-care patients with coronavirus disease (COVID-19) have become a social problem. One of their causes is hypoxemia without dyspnea which delays seeking medical attention. This was a retrospective study including patients registered in the COVID-19 Registry Japan, in which hospitalized patients with COVID-19 in 227 participating healthcare facilities were enrolled. The enrolled patients were divided into two groups: non-dyspneic patients with a peripheral capillary oxygen saturation (SpO2) ≤ 93% on admission (the hypoxemia without dyspnea group) and non-dyspneic patients with an SpO2> 93% (the control group). We conducted a multivariate logistic regression analysis to identify the factors associated with hypoxemia without dyspnea. 21544 patients were enrolled, 1035 (4.8%) patients were in the hypoxemia without dyspnea group, and 20509 (95.2%) patients were in the control group. The median respiratory rate (RR) of the hypoxemia without dyspnea group was higher than that of the control group (31/min vs. 18/min, p < 0.001). Age> 65, male, body mass index> 25, smoking, chronic obstructive pulmonary disease, other chronic lung disease, and diabetes mellitus were the independent factors associated with hypoxemia without dyspnea. Patients with those background should be closely monitored. RR is an important indicator of hypoxemia, even in the absence of dyspnea.

Safety of casirivimab/imdevimab administration in a SARS-CoV-2 positive maintenance dialysis patient in Japan.

Controlling excessive cytokine secretion is a crucial therapeutic strategy for managing coronavirus disease 2019 (COVID-19). Patients on dialysis are at a high risk of severe disease, given abnormal immune responses that can lead to prolonged inflammation. Moreover, patients undergoing dialysis have limited treatment options, as neither remdesivir nor baricitinib is available. The novel neutralizing monoclonal antibody cocktail REGEN-COV (formerly known as REGN-COV2; casirivimab/imdevimab), recently approved in Japan, is a promising drug for preventing severe diseases. However, there are few reports regarding its use in patients undergoing dialysis in Japan. Herein, we report the safe use of antibody cocktail therapy in patients with COVID-19 on hemodialysis receiving maintenance dialysis in Japan. Infusion reactions were not observed during administration. Due to the increasing number of patients with COVID-19 and the limited capacity of the healthcare system, antibody cocktail therapy needs to be enhanced. Antibody cocktail therapy for severe diseases can be safely administered to patients undergoing dialysis who do not require supplemental oxygen.

Factors associated with high antibody titer following coronavirus disease among 581 convalescent plasma donors: A single-center cross-sectional study in Japan.

INTRODUCTION: The ability to predict which patients with a history of coronavirus disease (COVID-19) will exhibit a high antibody titer is necessary for more efficient screening of potential convalescent plasma donors. We aimed to identify factors associated with a high immunoglobulin G (IgG) titer in Japanese convalescent plasma donors after COVID-19. METHODS: This cross-sectional study included volunteers undergoing screening for convalescent plasma donation after COVID-19. Serum anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) S-protein IgG antibodies were measured using a high-sensitivity chemiluminescence enzyme immunoassay. RESULTS: IgG antibodies were measured in 581 patients, 534 of whom had full information of selected independent variables. Multiple linear regression analysis revealed that increasing age (1.037 [1,025, 1.048]), days from symptom onset to sampling (0.997 [0.995, 0.998]), fever (1.664 [1.226, 2.259]), systemic corticosteroid use during SARS-CoV-2 infection (2.382 [1.576, 3.601]), and blood type AB (1.478 [1.032, 2.117]) predict antibody titer. CONCLUSION: Older participants, those who experienced fever during infection, those treated with systemic corticosteroids during infection, those from whom samples were obtained earlier after symptom onset, and those with blood type AB are the best candidates for convalescent plasma donation. Therefore, these factors should be incorporated into the screening criteria for convalescent plasma donation after SARS-CoV-2 infection.

Fatty liver on computed tomography scan on admission is a risk factor for severe coronavirus disease.

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.

Evaluation of the efficacy of anticoagulation therapy in reducing mortality in a nationwide cohort of hospitalized patients with coronavirus disease in Japan.

OBJECTIVES: To determine whether anticoagulation therapy improves outcomes in patients with coronavirus disease 2019 (COVID-19) in Japan given their lower risk of thrombosis compared with Western cohorts. METHODS: The efficacy of anticoagulation therapy in hospitalized patients with COVID-19 was evaluated using a nationwide registry: the COVID-19 Registry Japan. The inverse probability of weight treatment method was used to adjust for baseline confounders in the anticoagulation and non-anticoagulation groups. RESULTS: Of the 1748 patients included, anticoagulants were used in 367 patients (treatment group). The patients in the anticoagulant group were older, predominantly male, and often presented with obesity, hyperlipidaemia, hypertension, diabetes and elevated D-dimer levels. Twenty-nine-day mortality was 7.6% in the whole cohort (treatment group, 11.2%; no treatment group, 6.6%), 6% in patients who were not treated with steroids (treatment group, 12.3%; no treatment group, 5.2%), and 11.2% in patients treated with steroids (treatment group, 10.5%; no treatment group, 11.8%). Mortality in the whole cohort was similar between the treatment and no treatment groups (P=0.99), and an insignificant decreasing trend in mortality was observed in patients treated with steroids (P=0.075). CONCLUSIONS: Anticoagulants may be beneficial in Asians, in whom comorbidities and risk of thrombosis may differ from other ethnic groups.

Clinical and radiological findings of silent hypoxia among COVID-19 patients.

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 <94%, were extracted. Eight patients (3.0%) met the criteria for "silent hypoxia." The median age was 61 years (interquartile range [IQR]: 48.8-72.3), and five (62.5%) were men. All patients had consolidation on CT and showed a moderate to high COVID-19 CT severity score (median: 13.5, IQR: 10.8-15.3). The median FIO2 of the maximum oxygen required was 55 (IQR: 28-70)%. Two patients (25.0%) were intubated, and one patient (12.5%) underwent extracorporeal membrane oxygenation. Some COVID-19 patients with "silent hypoxia" may develop severe disease. Close and accurate monitoring of patients using arterial blood gas and pulse oximetry is necessary, regardless of their symptoms.

Development of delayed neurologic sequelae in acute carbon monoxide poisoning cases caused by briquette-based kotatsu: A case-control study.

ABSTRACT: Briquette-based kotatsu, a traditional Japanese heating system, is still used in rural areas and has been linked to the development of acute carbon monoxide (CO) poisoning. This study aimed to investigate the occurrence of delayed neurologic sequelae (DNS) in patients with acute CO poisoning caused by briquette-based kotatsu.This retrospective study included 17 patients treated for acute CO poisoning due to briquette-based kotatsu, between April 2017 and March 2020. Patients were divided into either a sequelae group (3 patients) or a non-sequelae group (14 patients) based on the presence or absence, respectively, of DNS. Demographic data, kotatsu characteristics, clinical findings, and therapies were compared between the 2 groups.Significant differences were noted in patient posture during their initial discovery. Specifically, all non-sequelae patients only had their legs under the kotatsu quilt and all sequelae patients had their entire bodies under the kotatsu quilt (P = .001). There were no statistically significant differences in carbon monoxide levels in hemoglobin (CO-Hb) or the creatine-kinase myocardial band (CK-MB), between the 2 groups; however, troponin-I levels were significantly higher in the sequelae group (P = .026). Abnormal head imaging findings were noted in 2 sequelae-group patients, with a significant difference between the groups (P = .025).We speculate that acute CO poisoning, caused by briquette-based kotatsu, may lead to DNS more frequently in patients in who cover their entire body with the kotatsu quilt and are found in this position. Patients should be warned about the dangers of acute CO poisoning when using briquette-based kotatsu.

External validation and update of prediction models for unfavorable outcomes in hospitalized patients with COVID-19 in Japan.

INTRODUCTION: Most of the currently used prognostic models for COVID-19 are based on Western cohorts, but it is unknown whether any are applicable to patients with COVID-19 in Japan. METHODS: This retrospective cohort study included 160 patients with COVID-19 who were admitted to the National Center for Global Health and Medicine between January 26, 2020 and July 25, 2020. We searched PubMed for prognostic models for COVID-19. The predicted outcome was initiation of respiratory support or death. Performance of the candidate models was evaluated according to discrimination and calibration. We recalibrated the intercept of each model with our data. We also updated each model by adding ß2-microglobulin (ß2MG) to the model and recalculating the intercept and the coefficient of ß2MG. RESULTS: Mean patient age was 49.8 years, 68% were male, 88.7% were Japanese. The study outcomes occurred in 15 patients, including two deaths. Two-hundred sixty-nine papers were screened, and four candidate prognostic models were assessed. The model of Bartoletti et al. had the highest area under receiver operating characteristic curve (AUC) (0.88; 95% confidence interval 0.81-0.96). All four models overestimated the probability of occurrence of the outcome. None of the four models showed statistically significant improvement in AUCs by adding ß2MG. CONCLUSIONS: Our results suggest that the existing prediction models for COVID-19 overestimate the probability of occurrence of unfavorable outcomes in a Japanese cohort. When applying a prediction model to a different cohort, it is desirable to evaluate its performance according to the prevalent health situation in that region.

Hemoptysis and a Newly Formed Lung Bulla in a Case of Convalescent COVID-19 Pneumonia.

Coronavirus disease 2019 (COVID-19) is a novel infectious disease affecting the general population worldwide. A fever and cough are the common clinical presentations of COVID-19. In most of these patients, computed tomography (CT) shows bilateral peripheral ground-glass opacities. We herein report a case of hemoptysis and lung bulla in the convalescent phase of COVID-19. Based on the clinical observations, alveolar destruction was likely associated with hemoptysis and bulla formation. Therefore, we suggest the follow-up of COVID-19 patients whose clinical parameters indicate alveolar damage, even after their symptoms improve.