The humoral and cellular immune responses following booster vaccination with SARS-CoV-2 mRNA in people living with human immunodeficiency virus

INTRODUCTION

People living with human immunodeficiency virus (PLWH) have higher mortality rates from COVID-19 than those without HIV. Additionally, the seroconversion rate of antibodies following a second dose of SARS-CoV-2 vaccine is lower in PLWH than non-infected individuals, indicating the need for booster vaccination. Here, we evaluated the humoral and cellular immune responses to booster SARS-CoV-2 vaccination in PLWH.

METHODS

The dynamics of anti-spike IgG titers and antigen-specific interferon (IFN)-γ levels to SARS-CoV-2 vaccination were assessed over a 6-month period following a third vaccination of 34 PLWH.

RESULTS

Antibody titers for humoral immunity were 50 % lower at 24 weeks post-vaccination than those at 12 weeks. However, those at 24 weeks after the booster vaccination were approximately eight times higher than before. Regarding cellular immunity, IFN-γ levels at 24 weeks after the third vaccination were lower than those at 12 weeks, but nearly 90 % of participants maintained a cut-off value of ≥0.15 IU/mL. A comparison between two groups with CD4+ T lymphocytes counts of <500/μL or ≥500/μL exhibited no statistically significant differences in antibody or IFN-γ levels. However, in the group with CD4+ T lymphocyte counts of <500/μL, the rate of IFN-γ above the cut-off value at 24 weeks after the booster vaccination was lower than that of ≥500/μL.

CONCLUSION

An immune response is expected in PLWH given successful antiretroviral therapy with booster SARS-CoV-2 vaccination. However, caution should be exercised for cases with low CD4+ T-lymphocyte counts. (240/250 words).

A delayed diagnosis of fascioliasis: The importance of appropriate fecal diagnostic method

Fascioliasis, a zoonotic helminthiasis, occurs sporadically in Japan. In this report, we describe a case of fascioliasis that was initially difficult to diagnose because the fecal examination method was negative for the Fasciola sp. eggs. A 64-year-old man living in Shimonoseki City, Japan, presented with fatigue and anorexia. Laboratory tests showed hepatic dysfunction and eosinophilia. Abdominal dynamic contrast-enhanced computed tomography and magnetic resonance cholangiopancreatography suggested intrahepatic biliary cysts. Thereafter, fever and night sweats persisted, and positron emission tomography and biopsy of the porta hepatis lymph node were performed on suspicion of malignancy. However, histopathological diagnosis found non-specific inflammation. As fascioliasis was suspected due to eosinophilia and the multiple hepatic masses, fecal egg examination was performed by an external private laboratory, which adopted the flotation method and reported the absence of parasite eggs. However, fecal examination was retried in our laboratory using the formalin-ether concentration method, and we detected Fasciola sp. eggs. This case suggests that misdiagnosis may occur depending on the fecal examination method; thus, it is necessary to choose a suitable method for certain parasite species.

Immunosuppressive therapy and humoral response to third mRNA COVID-19 vaccination with a six-month interval in rheumatic disease patients

OBJECTIVES

To evaluate the long-term impact of immunosuppressive therapeutic agents on antibody response to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) mRNA vaccination in patients with autoimmune rheumatic diseases (AIRD) in order to propose a strategy for annual vaccination.

METHODS

This prospective multicentre cohort study evaluated the humoral response to second and third BNT162b2 and/or mRNA-1273 vaccines in 382 Japanese AIRD patients classified into 12 different medication groups and in 326 healthy controls (HCs). The third vaccination was administered six months after the second vaccination. Antibody titres were measured using the Elecsys Anti-SARS-CoV-2 S assay.

RESULTS

The seroconversion rate and antibody titres were lower in AIRD patients than in HCs 3-6 weeks after the second vaccination and 3-6 weeks after the third vaccination. Seroconversion rates were <90% after the third vaccination in patients receiving mycophenolate mofetil and rituximab. Antibody levels after the third vaccination were significantly lower in the groups prescribed TNF inhibitor with or without methotrexate, abatacept and rituximab or cyclophosphamide than those of HCs in a multivariate analysis adjusting for age, sex, and glucocorticoid dosage. The third vaccination induced an adequate humoral response in patients treated with sulfasalazine, bucillamine, methotrexate monotherapy, iguratimod, interleukin-6 inhibitors or calcineurin inhibitors including tacrolimus.

CONCLUSIONS

Repeated vaccinations in many immunosuppressed patients produced antibody responses similar to those observed in HCs. In contrast, annual vaccination in patients receiving TNF inhibitors, abatacept, mycophenolate mofetil and rituximab may require caution.

Characteristics of preventive intervention acceptance for international travel among clients aged 60 years and older from a Japanese multicenter pretravel consultation registry

OBJECTIVES

Pretravel consultation (PTC) is important for older adults owing to health problems associated with overseas travel. Although older adults in Japan, their PTC characteristics are less known. This study aimed to investigate the epidemiology of clients aged ≥ 60 years based on data from the Japan Pre-travel Consultation Registry (J-PRECOR).

METHODS

Clients aged ≥ 60 years who visited J-PRECOR cooperative hospitals from February 1, 2018, to May 31, 2022, were included. The primary endpoint was a comparison of prescriptions for vaccines for hepatitis A, tetanus toxoid, and malaria prophylaxis in travelers to high-risk malaria countries in yellow fever vaccination (YFV)-available facilities with and without YFV.

RESULTS

In total, 1000 clients (median age: 67 years) were included. Although 523 clients were immunized with YFV, only 38.6% of the 961 unimmunized clients were vaccinated with the tetanus toxoid-containing vaccine. Malaria chemoprophylaxis was prescribed to 25.7% of clients traveling for ≤55 days. At YFV-capable institutes, 557 clients traveling to yellow fever risk countries took PTC, 474 of whom received YFV and 83 were unvaccinated. Lower age (odds rate 0.85 per 1 year; 95% CI 0.80-0.90) and lower hepatitis A vaccination rate (0.29; 95% CI 0.14-0.63) were significantly associated with YFV.

CONCLUSIONS

Preventive interventions other than YFV should be offered to older adults.

Distinct features of SARS-CoV-2 humoral immunity against Omicron breakthrough infection

BACKGROUND

SARS-CoV-2 Omicron breakthrough infection (Omicron-BTI) after vaccination has been frequently observed. A more detailed understanding of the humoral immunity against Omicron-BTI is required.

METHODS

We measured strain-specific live-virus based neutralizing activity, anti-spike IgG, and anti-receptor-binding domain (RBD) IgG titers in individuals with Omicron/BA.1-BTI and directly compared them with controls with diverse combinations of wild-type (WT) mRNA vaccination and infection history.

RESULTS

Omicron-BTI individuals showed markedly higher neutralizing titers against all the WT, Delta, and Omicron strains in convalescent sera, compared with unvaccinated Omicron-infection individuals with only Omicron neutralizing activity. Similar tendencies were found in strain-specific anti-spike and anti-RBD IgG titers. The Omicron-specificity (BA.1/WT neutralizing ratio), Omicron-neutralizing efficiency per antibody unit, and anti-Omicron RBD-directivity of anti-spike antibodies in Omicron-BTI individuals were all significantly lower than those in unvaccinated Omicron-infection individuals, but they were equivalent to or higher than those in uninfected vaccinees. The induction of Omicron-specific neutralizing activity after Omicron-BTI was not weakened for eight months from the last vaccination.

CONCLUSIONS

These findings suggest that cross-reactive vaccine-induced immunity was intensively stimulated following Omicron breakthrough infection, which contributed to Omicron neutralization. Measuring SARS-CoV-2 variant-specific antibody levels as well as neutralizing activity is useful for evaluating humoral immunity after breakthrough infection in the current situation of antigenic gaps between vaccinated and epidemic (Omicron sub-lineages) strains.

Correlation between specific antibody response to wild-type BNT162b2 booster and the risk of breakthrough infection with omicron variants: Impact of household exposure in hospital healthcare workers

BACKGROUND

The emergence of omicron variants exhibiting antigenic changes has led to an increase in breakthrough infection among individuals with a wild-type SARS-CoV-2 vaccine booster. The correlation between post-booster spike-specific antibodies and omicron infection risk remains unclear.

METHODS

This prospective cohort study included SARS-CoV-2-naive healthcare workers with three-dose BNT162b2. Post-booster spike-specific IgG and interferon-γ levels were measured. Breakthrough infection was documented during a 10-month omicron-predominant period. Household and healthcare contacts were followed to identify subsequent infections. The IgG titers were additionally measured at the end of follow-up, and the titers at exposure were estimated from the two-point titers.

RESULTS

Of 333 participants, 89 developed infection, of whom 37 (41.6 %) were household contacts. Kaplan-Meier curves indicated that higher IgG titers were significantly correlated with lower cumulative infection incidence (p = 0.029), whereas the interferon-γ levels were not (p = 0.926). Multivariate Cox analysis showed that increasing IgG titers were associated with a reduced hazard ratio (HR) of 0.26 (95% CI, 0.12-0.55). Household exposure posed a greater infection risk than healthcare exposure (HRs, 11.24 [6.88-18.40] vs. 2.82 [1.37-5.44]). The difference in geometric mean IgG titers of infected and uninfected participants was significant among household contacts (20,244 AU/mL vs. 13,842 AU/mL, p = 0.031). Estimation of IgG titers at exposure showed a significantly higher infection incidence in those exposed with titers of <3,000 AU/mL than in those with higher titers (79.2 % vs. 32.3 %, p < 0.001).

CONCLUSIONS

Spike-specific antibodies induced by a wild-type SARS-CoV-2 vaccine booster are suggested to be effective in protecting against omicron infection. Household exposure would be a significant source of infection for hospital healthcare workers.

Evaluation of Neutralizing Activity against Omicron Subvariants in BA.5 Breakthrough Infection and Three-Dose Vaccination Using a Novel Chemiluminescence-Based, Virus-Mediated Cytopathic Assay

Neutralizing potency of humoral immune responses induced by prior infection or vaccination is vital for protecting of individuals and population against severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2). However, the emergence of viral variants that can evade neutralization by vaccine- or infection-induced immunity is a significant public health threat and requires continuous monitoring. Here, we have developed a novel scalable chemiluminescence-based assay for assessing SARS-CoV-2-induced cytopathic effect to quantify the neutralizing activity of antisera. The assay leverages the correlation between host cell viability and ATP levels in culture to measure the cytopathic effect on target cells induced by clinically isolated, replication-competent, authentic SARS-CoV-2. With this assay, we demonstrate that the recently arisen Omicron subvariants BQ.1.1 and XBB.1 display a significant decrease in sensitivity to neutralization by antibodies elicited from breakthrough infections with Omicron BA.5 and from receipt of three doses of mRNA vaccines. Thus, this scalable neutralizing assay provides a useful platform to assess the potency of acquired humoral immunity against newly emerging SARS-CoV-2 variants. IMPORTANCE The ongoing global pandemic of SARS-CoV-2 has emphasized the importance of neutralizing immunity in protecting individuals and populations against severe respiratory illness. In light of the emergence of viral variants with the potential to evade immunity, continuous monitoring is imperative. A virus plaque reduction neutralization test (PRNT) is a "gold standard" assay for analyzing neutralizing activity for authentic viruses that form plaques, like influenza virus, dengue virus, and SARS-CoV-2. However, this method is labor intensive and is not efficient for performing large-scale neutralization assays on patient specimens. The assay system established in this study allows for the detection of a patient's neutralizing activity by simply adding an ATP detection reagent, providing a simple evaluation system for neutralizing activity of antisera as an alternative to the plaque reduction method. Our extended analysis of the Omicron subvariants highlights their increasing capability to evade neutralization by both vaccine- and infection-induced humoral immunity.

Relationship between the cholesterol and triglyceride content of lipoprotein subclasses and carotid intima-media thickness: A cross-sectional population-based study

BACKGROUND

The association between lipoprotein subclasses and carotid intima-media thickness (cIMT) progression has yet to be fully evaluated. We assessed which lipoprotein subclasses were associated with maximum cIMT levels in the general population.

METHODS

In this study, cholesterol and triglyceride content of 20 lipoprotein subclasses were analyzed using gel permeation high-performance liquid chromatography (GP-HPLC) in 864 Japanese women and men (mean age 57 y, free of chronic liver or kidney diseases and off lipid-lowering, hormone replacement, or adrenocorticosteroid medications). Univariate and multivariate regression analyses and univariate and partial correlation analyses were performed to examine the relationships between lipoprotein subclasses and maximum cIMT levels.

RESULTS

After adjusting for age, sex, systolic blood pressure, smoking, diabetes, and anti-hypertensive agents, elevated low-density lipoprotein (LDL)-2 and -3 cholesterol (particle diameter 25.5 nm and 23.0 nm, respectively; medium and small LDL) were associated with higher maximum cIMT levels in both women and men (all p for trend < 0.05). These associations were significant even after participants taking anti-diabetic or anti-hypertensive agents were excluded. No significant associations were found between any triglyceride subclasses and maximum cIMT levels.

CONCLUSIONS

Smaller LDL particle cholesterol values are the most atherogenic lipoprotein parameter.

Achievement of sufficient antibody response after a fourth dose of wild-type SARS-CoV-2 mRNA vaccine in nursing home residents

BACKGROUND

Infection control during COVID-19 outbreaks in nursing facilities is a critical public health issue. Antibody responses before and after the fourth (second booster) dose of wild-type severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine in nursing home residents have not been fully characterized.

METHODS

This study included 112 individuals: 54 nursing home residents (mean age: 84.4 years; 35 SARS-CoV-2-naive and 19 previously infected) and 58 healthcare workers (mean age: 47.7 years; 25 SARS-CoV-2-naive and 33 previously infected). Antispike and antinucleocapsid antibody responses to messenger RNA vaccination were evaluated using serum samples collected shortly and 5 months after the third dose, and shortly after the fourth dose.

RESULTS

The median immunoglobulin G (IgG) level in SARS-CoV-2-naive residents was similar to that in SARS-CoV-2-naive healthcare workers after the fourth dose (24,026.3 vs. 30,328.6 AU/mL, p = .79), whereas after the third dose the IgG level of SARS-CoV-2-naive residents was approximately twofold lower than that in SARS-CoV-2-naive healthcare workers. In residents with previous SARS-CoV-2 infection, timing of infection in relation to vaccination affected the kinetics of antibody responses. Residents infected after the third dose showed the highest IgG levels after the fourth dose among all groups (median: 64,328.8 AU/mL), in contrast to residents infected before initiating vaccination with antibody levels similar to those of SARS-CoV-2-naive residents.

CONCLUSIONS

Advanced aged nursing home residents, poor responders in the initial SARS-CoV-2 vaccine series, could achieve sufficient antibody responses after the fourth (second booster) vaccination, comparable to those of younger adults.

Impact of peripheral mitochondrial DNA level on immune response after COVID-19 vaccination

The efficacy of vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the elderly is partially hindered by immunosenescence, resulting from decreased mtDNA levels. This study evaluated the correlation between mtDNA levels in peripheral leukocytes and immune response to the SARS-CoV-2 vaccine. Two hundred ten participants (median age 79.5 years), including 83 frail residents/inpatients and 70 robust outpatients, were analyzed. Anti-spike IgG antibody (IgG(S)) titers were serially measured from before the first vaccination to after the third vaccination. The mtDNA levels and cell-mediated immunity were measured in 45 elderly and 22 elderly individuals two months after the third vaccination. The robust group had consistently higher IgG(S) titers than the frail group. The mtDNA levels positively correlated with IgG(S) titers, as well as with cell-mediated immunity. These findings suggest that mtDNA levels positively impact vaccine-induced immunity. Further studies into maintaining mtDNA levels may provide insights into immunosenescence in the elderly.

Breakthrough candidemia with hematological disease: Results from a single-center retrospective study in Japan, 2009-2020

Breakthrough candidemia (BrC) is a significant problem in immunocompromised patients, particularly those with hematological disorders. To assess the characteristics of BrC in patients with hematologic disease treated with novel antifungal agents, we collected clinical and microbiological information on said patients from 2009 to 2020 in our institution. Forty cases were identified, of which 29 (72.5%) received hematopoietic stem cell transplant (HSCT)-related therapy. At BrC onset, the most administered class of antifungal agents were echinocandins, administered to 70% of patients. C. guilliermondii complex was the most frequently isolated species (32.5%), followed by C. parapsilosis (30%). These two isolates were echinocandin-susceptible in vitro but had naturally occurring FKS gene polymorphisms that reduced echinocandin susceptibility. Frequent isolation of these echinocandin-reduced-susceptible strains in BrC may be associated with the widespread use of echinocandins. In this study, the 30-day crude mortality rate in the group receiving HSCT-related therapy was significantly higher than in the group not receiving it (55.2% vs 18.2%, p = 0.0297). Most patients affected by C. guilliermondii complex BrC (92.3%) received HSCT-related therapy and had a 30-day mortality rate of 53.8%; despite treatment administration, 3 of 13 patients had persistent candidemia. Based on our results, C. guilliermondii complex BrC is a potentially fatal condition in patients receiving HSCT-related therapy with echinocandin administration.

Platypnea-Orthodeoxia Syndrome in Coronavirus Disease 2019 Pneumonia: A Case Report and Literature Review

Platypnea-orthodeoxia syndrome (POS) is a rare disorder associated with coronavirus disease 2019 (COVID-19) pneumonia. However, POS may be underdiagnosed. We report the case of a 59-year-old female patient with POS complicated by pulmonary embolism in COVID-19. Imaging revealed ground-glass opacities predominantly in the lower lobes and a pulmonary embolus in the right upper lobe. She was diagnosed with POS due to marked postural discrepancies between supine and upright oxygen saturations and blood oxygenation. Intracardiac shunt, one of the etiologies of POS, was not detected by bubble contrast echocardiography, and postural de-saturation gradually improved with methylprednisolone and edoxaban administration. In our literature review, only 3 of the 16 patients with POS associated with COVID-19 had cardiac shunting, suggesting that moderate to severe COVID-19 causes POS without cardiac shunts. COVID-19-associated vasculopathy and lower lung lesion predominance in COVID-19 pneumonia may cause ventilation-perfusion mismatch due to gravitational shunting of blood into the poorly ventilated lower lungs in the upright position, which may ultimately cause POS. Hypoxemia impedes rehabilitation, whereas early initiation of supine positioning in bed, with knowledge of the pathophysiology of POS, may have a positive effect.

Abstract P555: Variants of Neurocan, a Nonalcoholic Fatty Liver Disease Risk Allele, Are Associated With Plaque Development in the Carotid Artery Over 5 Years

Introduction: Nonalcoholic fatty liver disease (NAFLD) genetic risk alleles are associated with lipid metabolism. However, the association between those variants and atherosclerosis has not yet been fully evaluated.

Hypothesis: We hypothesized that NAFLD risk alleles are associated with the progression of atherosclerosis.

Methods: A total of 1,050 Japanese men and women (median age 55 years and median body mass index 22.9 kg/m2) free of cardiovascular disease, dyslipidemia, hypertension, and diabetes were studied. . Among NAFLD risk SNPs, variants of patatin-like phospholipase domain containing 3 ( PNPLA3 ), transmembrane 6 superfamily member 2 ( TM6SF2 ), glucokinase regulator ( GCKR ), and neurocan ( NCAN ) were assessed. Plasma total cholesterol, low-density lipoprotein cholesterol (LDL-C), small dense LDL-C, LDL-triglycerides, high-density lipoprotein cholesterol (HDL-C), HDL3-C, triglycerides, remnant-like particle cholesterol, lipoprotein(a), and adiponectin were also measured. At both baseline and after a five-year follow-up, carotid intima-media thickness (cIMT) was assessed. Atherosclerosis was defined as cIMT ≥ 1.1mm or the presence of a plaque. Univariate and multivariate analyses and chi-square and Fisher’s exact tests were performed to examine the associations between NAFLD risk SNPs, lipoproteins, and progression of atherosclerosis.

Results: Both median and maximum cIMT of total participants did not differ between baseline and after a five-year follow-up. Among participants without atherosclerosis at baseline, the rate of plaque development was 13.8% (121/880) with the major allele (CC) of NCAN being significantly higher than other alleles. Variants of NCAN were associated with the development of plaque ( P = 0.04, Fisher’s exact test). Participants with the CT allele of NCAN had significantly lower RLP cholesterol at baseline than those with the CC allele (7.6 mg/dl vs. 10.5 mg/dl, P = 0.02). Variants of PNPLA3 , TM6SF2 , GCKR , and NCAN were not associated with changes in lipoproteins.

Conclusions: A NCAN variant, one of the NAFLD risk SNPs, was associated with the development of plaque independent of lipoprotein alterations among healthy Japanese participants.

Study of the effects of in-person attendance at academic conferences on the health of the attendees under COVID-19 pandemic

OBJECTIVE

To analyze the effects of in-person attendance at an academic conference held during the Covid-19 pandemic on the health of the attendees, as assessed based on symptoms such as fever and cough attributed to infection with the Covid-19 virus.

METHODS

A questionnaire was used to survey the members of the Japan Society of Obstetrics and Gynecology (JSOG) about their health during the period from August 7 to August 12, 2022, after the 74th Annual Congress of the JSOG, which was held August 5 to 7.

RESULTS

Our survey yielded responses from 3054 members (1566 of whom had attended the congress in person and 1488 of whom had not attended in person); 102 (6.5%) of the in-person attendees and 93 (6.2%) of the people who did not attend in person reported problems with their health. No statistically significant difference was found between these two groups (p = 0.766). In a univariate analysis of factors affecting the presence of health problems, attendees with age ≥60 years had significantly fewer health problems than attendees who were in their 20s (odds ratio: 0.366 [0.167-0.802; p = 0.0120]). In a multivariate analysis, attendees who had received four vaccine shots had significantly fewer health problems than attendees who had received three shots (odds ratio: 0.397 [0.229-0.690, p = 0.0010]).

CONCLUSION

Congress attendees who took precautions at the congress to avoid being infected and who had a high vaccination rate did not develop significantly more health problems associated with in-person attendance at the congress.

SARS-CoV-2 strain-specific anti-spike IgG ELISA utilizing spike protein produced by silkworms

BACKGROUND

A cost-effective and eco-friendly method is needed for the assessment of humoral immunity against SARS-CoV-2 in large populations.

OBJECTIVE

We investigated the performance of an ELISA that uses silkworm-produced proteins to quantify the strain-specific anti-Spike IgG (anti-S IgG) titer.

METHODS

The OD values for the anti-His-tag antibody, a standard material of ELISA quantification, were measured. Correlations between the ELISA for each strain and the Abbott SARS-CoV-2 IgG II Quant assay for the wild type were evaluated with serum samples from nine participants with various infection and vaccination statuses.

RESULTS

Linear dose-responses were confirmed by high coefficients of determination: 0.994, 0.994, and 0.996 for the wild-type, Delta, and Omicron (BA.1) strain assays, respectively. The coefficient of determination for the wild-type and Delta strain assays was high at 0.959 and 0.892, respectively, while the Omicron strain assay had a relatively low value of 0.563. Booster vaccinees showed similar or higher titers against all strains compared to infected persons without vaccination. The Omicron-infected persons without vaccination had lower antibody titers against wild type than did the vaccinated persons.

CONCLUSIONS

This study provides data indicating that the ELISA with silkworm-produced proteins makes it possible to discriminate and quantify the strain-specific anti-S IgG antibody induced by vaccination or infection.

Clinical characteristics and factors related to infection with SCCmec type II and IV Methicillin-resistant Staphylococcus aureus in a Japanese secondary care facility: a single-center retrospective study

OBJECTIVES

Differences in virulence genes, including psm-mec, which is a phenol-soluble modulin-mec (PSM-mec) encoding gene, of predominant staphylococcal cassette chromosome mec (SCCmec) types II and IV Methicillin-resistant Staphylococcus aureus (MRSA) may contribute to the virulence and clinical features of MRSA in Japan. We aimed to clarify the clinical characteristics and risk factors of infection among SCCmec types II and IV MRSA isolates from a Japanese secondary acute care hospital.

METHODS

We analysed 58 SCCmec type II and 83 SCCmec type IV MRSA isolates collected from blood, central venous catheter tips, deep or superficial tissues, and sputum.

RESULTS

SCCmec type II MRSA risk factors for progression to infection were seb, enterotoxin gene cluster, psm-mec mutation, and vancomycin minimum inhibitory concentrations (MIC) of 1 or 2 mg/L as virulence factors (adjusted odds ratio [aOR] = 11.8; 95% confidence interval [CI]: 2.49-77.7; P = 0.004); solid tumour was a host factor (aOR = 25.9; 95% CI: 3.66-300; P = 0.003). SCCmec type IV MRSA risk factors were sea, cna, and vancomycin MIC of 1 or 2 mg/L as virulence factors (aOR = 3.14; 95% CI: 1.06-10.6; P = 0.049) and intravascular indwelling catheter as host factors (aOR = 3.78; 95% CI: 1.03-14.5; P = 0.045). Compared with SCCmec type II, SCCmec type IV MRSA resulted in more frequent bloodstream infections and higher Sequential Organ Failure Assessment scores.

CONCLUSION

We found that factors related to virulence genes and bacteriological and host characteristics are associated with SCCmec types II and IV MRSA infection and severity. These risk factors may be useful criteria for designing infection control programs.

Dynamics of anti-spike IgG antibody after a third BNT162b2 COVID-19 vaccination in Japanese health care workers

Objectives

Many countries are administering a third dose of some coronavirus disease 2019 (COVID-19) vaccines, but the evaluation of vaccine-induced immunity after boosting in East Asia is insufficient. This study aimed to evaluate anti-spike immunoglobulin G [IgG(S)] titers after the third BNT162b2 vaccination.

Methods

The dynamics of IgG(S) titers were assessed two months following the third BNT162b2 vaccination in 52 participants. All participants received the primary series of vaccination with BNT162b2 and received the third dose eight months after the second vaccination. Associations among the IgG(S) titer, baseline characteristics, and adverse reactions were also evaluated.

Results

The geometric mean titer of IgG(S) one month after the third vaccination was 17,400 AU/ml, which increased by approximately 30 times that immediately before the third vaccination. The rate of IgG(S) titer decline was significantly slower after the third vaccination (35.7%) than after the second vaccination (59.1%). The IgG(S) titer was significantly negatively associated with age (r = -0.31). Participants who had a headache at the time of vaccination showed significantly higher IgG(S) titers than those without a headache.

Conclusions

The IgG(S) titer induced by primary immunization with BNT162b2 waned over time. The third dose of BNT162b2 substantially increased the IgG(S) titer, with a slower rate of decline.

Characteristics and potential quality indicators for evaluating pre-travel consultations in Japan hospitals: the Japan Pretravel consultation registry (J-PRECOR)

Background

Awareness of pre-travel consultations (PTCs) and prevention methods for overseas travel-related diseases, and the understanding of PTCs among Japanese travelers and medical professionals remains low in Japan. A multicenter registry was established to examine PTCs in Japan. This study assessed the PTC implementation rate and examined the indicators of PTCs that can be used as criteria for evaluating quality.

Methods

Clients who presented for their PTCs at 17 facilities and were registered between February 1, 2018, and May 31, 2020, were included. Medical information was extracted retrospectively via a web-based system. Correlations between vaccination risk categories and advice/intervention proportions by the facility were evaluated using Spearman’s ordered phase relations (α = 0.05).

Results

Of the 9700 eligible clients (median age, 32 years; 880 [9.1%] aged < 16 years and 549 [5.7%] aged ≥65 years), the most common travel duration was ≥181 days (35.8%); higher among younger clients. The most common reason for travel was business (40.5%); the US (1118 [11.5%]) and Asia (4008 [41.3%]) were the most common destinations and continents, respectively. The vaccine number (median three per person) increased after the PTCs except for the tetanus toxoid. Only 60.8% of the clients recommended for malaria prophylaxis received anti-malarial agents. The gross national income; the incidence of human rabies, typhoid fever, falciparum malaria; and dengue risk category were associated with the percentage of hepatitis-A vaccines; explaining rabies post-exposure prophylaxis, typhoid-fever vaccinations, malaria-prophylaxis prescriptions; and mosquito repellants, respectively.

Conclusions

Although the characteristics of the travelers differed, the quality of the PTCs should be improved to address, for example, the lower rate of acceptance of malaria prophylaxis in Japan.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40794-021-00160-4.

No significant influence of pre-vaccination antipyretic use on specific antibody response to a BNT162b2 vaccine booster against COVID-19

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The influence of antipyretic use before a BNT162b2 booster is of concern.

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Anti-spike IgG titer and adverse reactions were compared by pre/non antipyretic use.

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The geometric mean IgG titer was comparable for the cases and controls.

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The frequency and severity of adverse reactions were also comparable.

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Consistent results were obtained after propensity score matching.

The relation between pre-vaccination antipyretic use and antibody responses to SARS-CoV-2 vaccination has been unclear. We measured the pre- and post-BNT162b2 booster spike-specific IgG titers and recorded antipyretic use and adverse reactions for SARS-CoV-2-naive hospital healthcare workers. The data of 20 cases who used antipyretics within 24 h before vaccination were compared to that of 281 controls. The post-booster geometric mean IgG titers were 15,559 AU/mL (95 % CI, 11,474–21,203) for the cases and 16,850 AU/mL (95 % CI, 15,563–18,243) for the controls (p = 0.622). No significant reduction in the frequency or severity of any of the solicited adverse reactions was found for the cases. Similar results were obtained after adjustment with propensity-score matching for demographic characteristics, baseline IgG titer, and post-vaccination antipyretic use. Antipyretic use within 24 h before vaccination would not affect mRNA COVID-19 vaccine-induced specific antibody responses and that postponement of vaccination due to pre-vaccination antipyretic use would be unnecessary.

Correlation of Postvaccination Fever With Specific Antibody Response to Severe Acute Respiratory Syndrome Coronavirus 2 BNT162b2 Booster and No Significant Influence of Antipyretic Medication

BACKGROUND

A severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccine booster elicits sufficient antibody responses that protect against coronavirus disease 2019, whereas adverse reactions such as fever have been commonly reported. Associations between adverse reactions and antibody responses have not been fully characterized, nor has the influence of antipyretic use.

METHODS

This is a prospective observational cohort study in Japan, following our prior investigation of BNT162b2 2-dose primary series. Spike-specific immunoglobulin G (IgG) titers were measured for SARS-CoV-2-naive hospital healthcare workers who received a BNT162b2 booster. The severity of solicited adverse reactions, including the highest body temperature, and self-medicated antipyretics were reported daily for 7 days following vaccination through a web-based self-reporting diary.

RESULTS

The data of 281 healthcare workers were available. Multivariate analysis extracted fever after the booster dose (β = .305, P < .001) as being significantly correlated with the specific IgG titers. The analysis of 164 participants with data from the primary series showed that fever after the second dose was associated with the emergence of fever after the booster dose (relative risk, 3.97 [95% confidence interval, 2.48-6.35]); however, the IgG titers after the booster dose were not associated with the presence or degree of fever after the second dose. There were no significant differences in the IgG titers by the use, type, or dosage of antipyretic medication.

CONCLUSIONS

These results suggest an independent correlation between mRNA vaccine-induced specific IgG levels and post-booster vaccination fever, without any significant influence of fever after the primary series. Antipyretic medications for adverse reactions should not interfere with the elevation of specific IgG titers.

Pronounced antibody elevation after SARS-CoV-2 BNT162b2 mRNA booster vaccination in nursing home residents

Background

Infection control during COVID‐19 outbreaks in nursing facilities is a critical public health issue. Antibody responses before and after the third (booster) dose of SARS‐CoV‐2 vaccination in nursing home residents have not been fully characterized.

Methods

This study included 117 individuals: 54 nursing home residents (mean age, 83.8 years; 39 SARS‐CoV‐2‐naive and 15 previously infected) and 63 healthcare workers (mean age, 45.8 years; 32 SARS‐CoV‐2‐naive and 31 previously infected). Anti‐spike (receptor‐binding domain [RBD]) and anti‐nucleocapsid antibody responses to BNT162b2 mRNA vaccination and their related factors were evaluated using pre‐ (shortly and 6 months after the second dose) and post‐booster vaccination samples.

Results

The median anti‐spike (RBD) IgG level in SARS‐CoV‐2‐naive residents 6 months after the second dose was the lowest among the four groups, with a decreasing rate of over 90%. The median rate of increase before and after the third dose in SARS‐CoV‐2‐naive residents was significantly higher than that in SARS‐CoV‐2‐naive healthcare workers (64.1‐ vs. 37.0‐fold, P = 0.003), with the highest level among the groups. The IgG ratio of SARS‐CoV‐2‐naive residents to healthcare workers after the second and third doses changed from one‐fifth (20%) to one‐half (50%). The rate of increase after the third dose in previously infected individuals was three‐ to fourfold, regardless of residents or healthcare workers.

Conclusions

Advanced aged nursing home residents, poor responders in the initial SARS‐CoV‐2 vaccine series, could obtain sufficient antibody responses with the additional booster dose, despite more than 6 months after the second.

Post-vaccination antibody evaluation for nosocomial SARS-CoV-2 delta variant breakthrough infection

Waning humoral immunity after mRNA vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a significant problem for public health. Breakthrough infection in hospitals over several months after vaccination has not been fully characterized, especially against the delta (B.1.617.2) variant. Here, we describe an outbreak in our hospital in September of 2021, mainly through serological evaluation of the breakthrough infection. This retrospective observational study was done at an emergency and acute care hospital with 204 beds and 486 staff members where most staff members (92.6%) had had their second BNT162b2 vaccination by May of 2021. The peri-infection anti-spike RBD protein IgG (anti-S IgG) titers (lowest values between 11 days before and 7 days after onset or diagnosis) of serum samples from the breakthrough-infected persons were quantified. We also logarithmically estimated the anti-S IgG titers during the exposure period in September of uninfected staff members from their samples collected in May and December 2021. Whole-genome sequencing was done on obtained samples. In this outbreak, twelve persons (ten inpatients and two staff members) were diagnosed with SARS-CoV-2 infection by Loop-Mediated Isothermal Amplification (LAMP) or RT-PCR, eight of whom had been vaccinated twice. Peri-infection anti-S IgG titers could be determined in seven of the eight breakthrough cases, with a geometric mean titer (GMT) of 1,034 AU/ml (95% confidence interval [CI], 398 to 2,686). Among 289 uninfected staff members with data from the two sampling points, the GMT of the estimated anti-S IgG titers during the exposure period in 51 staff members, who were working at the outbreak ward and potentially exposed but uninfected, and 238 other unexposed staff members were 1,458 AU/ml (95% CI, 1,196 to 1,777) and 1,628 AU/ml (95% CI, 1,500 to 1,766), respectively. All viruses from the eight samples for which whole-genome sequencing was available were identified as delta variants. Of the infected persons, one remained asymptomatic throughout the course of treatment, and eleven had an illness of mild to moderate severity, including ten who received monoclonal antibody cocktail (Casirivimab/imdevimab) therapy. Measurement and estimation of anti-spike antibody levels after SARS-CoV-2 vaccination would be helpful for evaluating the risk of breakthrough infection and for determining the necessity of booster vaccination.

Appropriateness of surgical antimicrobial prophylaxis in Japanese university hospitals

OBJECTIVE

This study aimed to determine the adherence to the Japanese surgical antimicrobial prophylaxis (SAP) guidelines in Japanese university hospitals.

DESIGN

A retrospective cohort study.

SETTING

Fifteen general and one dental university hospitals.

METHODS

We evaluated up to three cases of 18 designated surgeries regarding adherence to Japanese SAP guidelines: selection of antibiotics, timing of administration, re-dosing intervals, and duration of SAP. When all items were appropriate, surgery was defined as 'appropriate.'

RESULTS

In total, 688 cases (22-45 cases per surgery) were included. The overall appropriateness was 46.8% (322/688), and the appropriateness of each surgery ranged from 8.0% (2/25, cardiac implantable electronic device implantation) to 92.1% (35/38, distal gastrectomy). The appropriateness of each item was as follows: pre/intraoperative selections, 78.5% (540/688); timing of administrations, 96.0% (630/656); re-dosing intervals, 91.8% (601/656); postoperative selection, 78.9% (543/688); and duration of SAP, 61.4% (423/688). The overall appropriateness of hospitals ranged from 17.6% (9/51) to 73.3% (33/45). The common reasons for inappropriateness were the longer duration (38.5%, 265/688) and choice of antibiotics with a non-optimal antimicrobial spectrum before/during, and after surgery (19.0%, 131/688 and 16.8%, 116/688, respectively), compared to the guideline.

CONCLUSIONS

Adherence to the guidelines differed greatly between the surgeries and hospitals. Large-scale multicentre surveillance of SAP in Japanese hospitals is necessary to identify inappropriate surgeries, factors related to the appropriateness, and incidences of surgical site infections.

Clinical characteristics and treatment outcomes of carbapenem-resistant Enterobacterales infections in Japan

OBJECTIVES

The dissemination of difficult-to-treat carbapenem-resistant Enterobacterales (CRE) is of great concern. We clarified the risk factors underlying CRE infection mortality in Japan.

METHODS

We conducted a retrospective, multicentre, observational cohort study of patients with CRE infections at 28 university hospitals from September 2014 to December 2016, using the Japanese National Surveillance criteria. Clinical information, including patient background, type of infection, antibiotic treatment, and treatment outcome, was collected. The carbapenemase genotype was determined using PCR sequencing. Multivariate analysis was performed to identify the risk factors for 28-day mortality.

RESULTS

Among the 179 patients enrolled, 65 patients (36.3%) had bloodstream infections, with 37 (20.7%) infections occurring due to carbapenemase-producing Enterobacterales (CPE); all carbapenemases were of IMP-type (IMP-1: 32, IMP-6: 5). Two-thirds of CPE were identified as Enterobacter cloacae complex. Combination therapy was administered only in 46 patients (25.7%), and the 28-day mortality rate was 14.3%. Univariate analysis showed that solid metastatic cancer, Charlson Comorbidity Index ≥3, bloodstream infection, pneumonia, or empyema, central venous catheters, mechanical ventilation, and prior use of quinolones were significant risk factors for mortality. Multivariate analysis revealed that mechanical ventilation (OR: 6.71 [1.42-31.6], P = 0.016), solid metastatic cancers (OR: 5.63 [1.38-23.0], P = 0.016), and bloodstream infections (OR: 3.49 [1.02-12.0], P = 0.046) were independent risk factors for 28-day mortality.

CONCLUSION

The significant risk factors for 28-day mortality in patients with CRE infections in Japan are mechanical ventilation, solid metastatic cancers, and bloodstream infections.

Relation of fever intensity and antipyretic use with specific antibody response after two doses of the BNT162b2 mRNA vaccine

BACKGROUND

The reactogenicity of BNT162b2 COVID-19 vaccine has been commonly reported and antipyretic medications are often used for mitigating adverse reactions. Possible associations between the reactogenicity events and specific antibody responses have not been fully investigated, nor has the influence of using antipyretics.

METHODS

Serum samples were collected from hospital healthcare workers with no COVID-19 history and the SARS-CoV-2 spike-specific IgG titer after two doses was measured. Degree of solicited adverse reactions in a day, including the highest body temperature, were reported using a self-reporting diary for five days after each dose. The highest body temperature during the five days was divided into three grades (<37.0 °C, 37.0-37.9 °C, or ≥ 38.0 °C). Self-medicated antipyretics were reported using a questionnaire.

RESULTS

The data of 335 participants were available for analysis. Multivariate analysis extracted the fever grade after the second dose (standardized coefficient beta = 0.301, p < 0.0001), female sex (beta = 0.196, p = 0.0014), and age (beta = -0.119, p = 0.0495) as being significantly correlated with the IgG titers. The positive correlation of the fever grade after the second dose with the IgG titers was also observed when analyzed by sex and age. The use of antipyretics did not interfere with the IgG titers irrespective of the fever grade.

CONCLUSIONS

The fever intensity after the second dose was associated with the IgG titer and antipyretic medications may be beneficial to mitigate the suffering from adverse reactions, without interfering with the acquisition of sufficient antibody responses.

Dynamics of anti-Spike IgG antibody level after the second BNT162b2 COVID-19 vaccination in health care workers

Introduction

Methods

Results

Conclusions

Kyushu and Okinawa Population Study (KOPS): a large prospective cohort study in Japan

PURPOSE

The Kyushu and Okinawa Population Study (KOPS) was established to investigate gene-environmental interactions in non-communicable diseases in Japan. Besides collecting blood samples and anthropometric measurements, we also obtained medical histories, psychological status and lifestyle habits, including physical activities and dietary patterns.

PARTICIPANTS

KOPS is a community-based prospective cohort study and consists of participants from four southwestern areas in Japan. Baseline surveys were conducted between 2004 and 2007 (wave 1), and 2009 and 2012 (wave 2) at the sites of municipality-based health check-ups. A total of 17 077 participants were included, comprising 10 697 participants of wave 1 and 6380 participants of wave 2; the median age in both groups was 61 years. Among them, 3006 individuals participated in both wave 1 and wave 2 surveys.

FINDINGS TO DATE

We have focused on either risk or confounding factors for non-communicable diseases. We have assessed the clinical utility of the newly developed biomarkers for impaired glucose tolerance, such as urinary myo-inositol and glycated albumin, and atherosclerosis, such as small dense low-density lipoprotein cholesterol. We have conducted an international collaborative study with Framingham Offspring Study to investigate ethnic differences in impaired glucose tolerance and cardiovascular diseases. We have found that insulin resistance and deficiency might account for the ethnic differences in impaired glucose tolerance and cardiovascular disease risks. As gene-environmental interaction analyses, we found a synergic effect of interleukin 28B single nucleotide polymorphisms (SNPs) and gender on the spontaneous elimination of hepatitis C, and a beneficial interaction of SNPs of high-density lipoprotein cholesterol and gender on the impact of physical activity. In addition, we reported eight novel loci contributing to the development and severity of coronary artery disease from a large genome-wide association study.

FUTURE PLANS

We plan to investigate further the clinical utility of the newly developed biomarkers and the gene-environmental interactions using prospective data.

SARS-CoV-2 spike L452R variant evades cellular immunity and increases infectivity

Many SARS-CoV-2 variants with naturally acquired mutations have emerged. These mutations can affect viral properties such as infectivity and immune resistance. Although the sensitivity of naturally occurring SARS-CoV-2 variants to humoral immunity has been investigated, sensitivity to human leukocyte antigen (HLA)-restricted cellular immunity remains largely unexplored. Here, we demonstrate that two recently emerging mutations in the receptor-binding domain of the SARS-CoV-2 spike protein, L452R (in B.1.427/429 and B.1.617) and Y453F (in B.1.1.298), confer escape from HLA-A24-restricted cellular immunity. These mutations reinforce affinity toward the host entry receptor ACE2. Notably, the L452R mutation increases spike stability, viral infectivity, viral fusogenicity, and thereby promotes viral replication. These data suggest that HLA-restricted cellular immunity potentially affects the evolution of viral phenotypes and that a further threat of the SARS-CoV-2 pandemic is escape from cellular immunity.

Genetic testing and serological screening for SARS-CoV-2 infection in a COVID-19 outbreak in a nursing facility in Japan

Background

The Pandemic of coronavirus disease (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has critically impacted the spread of infection within nursing facilities. We evaluated the usefulness of genetic and serological tests conducted during a COVID-19 outbreak in a nursing facility in Japan.

Methods

After the first identification of SARS-CoV-2 infection, a comprehensive, facility- and/or unit-wide PCR testing from nasopharyngeal swabs was repeatedly performed in a three-unit facility including 99 residents with dementia and 53 healthcare personnel. Additionally, PCR testing was conducted separately for residents and staff with fever of ≥37.5 °C. Facility-wide serological testing, including rapid kit testing and quantitative assay, was conducted twice over 1 month apart.

Results

A total of 322 PCR and 257 antibody tests were performed. 37 (24.3%) of the 152 individuals (25/99 residents, 25.3%; 12/53 staff, 22.6%) were identified as PCR-positive. Seven residents died with a mortality of 7.1% (7/99). Among the 37 individuals, 10 (27.0%) were asymptomatic at the time of testing. PCR positivity was concentrated on one unit (Unit 1) (20/30 residents, 66.7%; 9/14 staff, 64.3%). The other units showed a limited spread of infection. In unit-wide and separate tests, PCR positivity detection was highly prevalent (22.9 and 44.4%, respectively) in Unit 1, compared with that in the other units. Serological testing identified two additional infected residents with a negative PCR result and showed that no staff was newly identified as infected.

Conclusions

Thorough PCR testing, in combination with comprehensive and separate tests, is critical for managing COVID-19 outbreaks in nursing facilities, particularly, in units considered an epicenter. Serological testing is also beneficial for tracing contacts, confirming the number of infected individuals, and authorizing the termination of the outbreak.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-05972-5.

Antimicrobial stewardship capacity and manpower needs in the Asia Pacific

OBJECTIVES

Antimicrobial stewardship is a strategy to combat antimicrobial resistance in hospitals. Given the burden and impact of antimicrobial resistance in the Asia Pacific, it is important to document capacity and gaps in antimicrobial stewardship programmes (ASP). We aimed to understand existing capacities and practices, and define the resources needed to establish antimicrobial stewardship where it is lacking.

METHODS

An anonymous online survey, consisting of questions on antimicrobial control at country, hospital and programme levels, was circulated to healthcare providers in the field of infectious diseases and microbiology through Asian Network for Surveillance of Resistant Pathogens, ReAct Group and the Australasian Society for infectious Diseases.

RESULTS

139 participants from 16 countries or regions completed the survey. The majority of participants were adult infectious diseases physicians (61/139, 43.9%) and microbiologists (31/139, 22.3%). Participants from 7 countries reported that antimicrobials can be obtained without prescriptions. Despite the high percentage (75.5%) of respondents working in large hospitals, only 22/139 participants (15.8%) from Australia, China, Singapore, Taiwan, Thailand and Vietnam reported having more than 10 infectious diseases physicians. Hospital empiric antimicrobial guidelines for common infections were available according to 110/139 (79.1%) participants. Pre-authorisation of antimicrobials was reported by 88/113 (77.9%) respondents while prospective audit and feedback was reported by 93/114 (81.6%). Automatic stop orders and culture-guided de-escalation were reported by only 52/113 (46.0%) and 27/112 (24.1%) respectively.

CONCLUSION

The survey reveals a wide range of ASP development in Asia Pacific. Establishing national workgroups and guidelines will help advance antimicrobial stewardship in this diverse region.

Parotitis caused by Mycobacteroides abscessus subspecies abscessus

Rapidly growing mycobacteria rarely causes parotitis. We report a rare case of Mycobacteroides abscessus subspecies abscessus (MAB) parotitis in a previously healthy 26-year-old woman. She presented to the previous hospital with a swelling over the right parotid region, and a computed tomography scan revealed multiple abscesses in the swollen parotid gland. Histopathology showed granulomatous inflammation with acid-fast bacilli; however, a subsequent culture failed to isolate mycobacterium. Despite repeated antibiotic therapy and multiple surgical interventions including partial incision and drainage of the abscesses, the parotitis did not resolved. At six months after presentation, she was referred to our institute. We performed enlarged resection of the necrotic tissue and abscesses, and the sample cultivated after homogenization was positive for mycobacterium. The isolate was finally identified as MAB. She underwent long-term postoperative antibiotic therapy for MAB, with a favorable outcome. To the best of our knowledge, this is the first case of MAB parotitis where the subspecies has been identified. MAB is much more intractable than the other subspecies. We highlight the importance of the correct identification of MAB, which leads to the appropriate treatment.

Clinical significance of SARS-CoV-2-specific IgG detection with a rapid antibody kit for COVID-19 patients

Background

The longitudinal observation of the detection of antibody responses to SARS‐CoV‐2 using antibody kits during the clinical course of COVID‐19 is not yet fully investigated.

Objectives

To understand the significance of the detection of anti‐SARS‐CoV‐2 antibodies, particularly IgG, using a rapid antibody kit, during the clinical course of COVID‐19 patients with different severities.

Methods

Sixty‐three serum samples from 18 patients (5 asymptomatic and 13 symptomatic patients) were retrospectively examined using a commercial SARS‐CoV‐2 IgM/IgG antibody kit. PCR positivity of patient samples was also examined as a marker of current SARS‐CoV‐2 infection.

Results

IgG antibodies were detected in all cases in this study. The IgG detection rates reached 100.0% in samples collected on day 13 or later. IgG seropositivity after an initial negative status was observed in 13 patients (3/5 asymptomatic and 10/13 symptomatic cases). Interestingly, the persistence of both PCR and IgG positivity was detected in seven cases, of which three were asymptomatic. The longest overlap duration of the PCR and IgG positivity was 17 days in asymptomatic status.

Conclusions

SARS‐CoV‐2‐specific IgG production can be detected in all infected individuals, using a rapid antibody kit, irrespective of clinical status. However, these findings suggest that, in some infected individuals, particularly those with asymptomatic status, the presence of virus‐specific IgG antibodies does not imply prompt viral clearance.

Clinical improvement in a patient with severe coronavirus disease 2019 after administration of hydroxychloroquine and continuous hemodiafiltlation with nafamostat mesylate

The number of people infected with severe acute respiratory syndrome coronavirus 2 is increasing globally, and some patients have a fatal clinical course. In light of this situation, the World Health Organization (WHO) declared coronavirus disease 2019 (COVID-19) a pandemic on March 11, 2020. While clinical studies and basic research on a treatment for COVID-19 are ongoing around the world, no treatment has yet been proven to be effective. Several clinical studies have demonstrated the efficacy of chloroquine phosphate and nafamostat mesylate with COVID-19. Here, we report the case of a Japanese patient with COVID-19 with severe respiratory failure who improved following the administration of hydroxychloroquine and continuous hemodiafiltlation with nafamostat mesylate. Hence, hydroxychloroquine with nafamostat mesylate might be a treatment option for severe COVID-19.

An Immunocompetent Case of Capnocytophaga canimorsus Infection Complicated by Secondary Thrombotic Microangiopathy and Disseminated Intravascular Coagulation

A 62-year-old woman with no previous history developed a Capnocytophaga canimorsus infection followed by thrombotic microangiopathy (TMA) and disseminated intravascular coagulation (DIC). She was treated with antibiotics and plasma exchange (PE) and recovered. C. canimorsus sepsis sometimes causes not only DIC but also TMA. The mortality of TMA is extremely high, so we should not hesitate to perform PE when a patient shows TMA symptoms.

Guidelines for standardizing cleansing and disinfection of gastrointestinal endoscopes

As part of the activities toward standardizing endoscopy procedures, the Japan Gastroenterological Endoscopy Society has prepared guidelines for cleansing and disinfection of gastrointestinal endoscopes. The environment of gastrointestinal endoscopy differs between Japan and advanced Western countries. In advanced Western countries, gastrointestinal endoscopy is performed almost exclusively at specialized facilities, where strict provisions are observed for cleansing and disinfecting endoscopes. In Japan, however, gastrointestinal endoscopy is performed even in small clinics, and the annual number of gastrointestinal endoscopy cases is enormous. In addition, the method for cleansing and disinfecting endoscopes differs among hospitals. Although there is a distinct lack of evidence for how gastrointestinal endoscopes are cleaned and disinfected, it is necessary to standardize the method for doing so to advance the field of endoscopic medicine.

1921. Attributable Inpatient Costs of Hospital-Onset Clostridium difficile Infection: A Nationwide Case–Control Study in Japan

Background

Hospital-onset Clostridium difficile infections (CDIs) have a considerable clinical and economic impact on both patients and payers. Quantifying the economic impact of CDIs can guide treatment strategies. However, previous studies have generally focused on acute care hospitals, and few have included cost estimates from nonacute care hospitals such as rehabilitation centres and long-term care facilities. The aim of this study was to quantify the hospital-onset CDI-attributable inpatient costs and length-of-stay durations in all healthcare institutions that provide inpatient care (including acute and nonacute care) in Japan.

Methods

Using national-level insurance claims data, we analyzed patients who had been hospitalized between April 2010 and December 2016. CDI case patients were identified and matched with non-CDI control patients using hospitalization year, treating hospital, age, sex, surgical procedure, comorbidities, and main diagnoses. Using multivariable regression analyses, we estimated the CDI-attributable inpatient costs and length-of-stay durations while adjusting for variations in factors such as age, sex, comorbidities, surgery, prescribed antibiotic, geographic region, and hospitalization year. We also analyzed the CDI-attributable inpatient costs and length-of-stay durations according to hospital type (acute care and rehabilitation/long-term care).

Results

The analysis was conducted using 3,768 matched pairs. Overall CDI-attributable inpatient costs and length-of-stay durations were US$3,213 and 11.96 days, respectively. Rehabilitation/long-term care hospitals had substantially higher inpatient costs and longer hospitalizations than acute care hospitals.

Conclusion

This study quantified the hospital-onset CDI-attributable inpatient costs and hospitalizations in both acute and nonacute care hospitals. The inclusion of nonacute care hospitals provides a more accurate representation of the economic burden of CDIs.

Disclosures

All authors: No reported disclosures.

Inpatient Expenditures Attributable to Hospital-Onset Clostridium difficile Infection: A Nationwide Case-Control Study in Japan

BACKGROUND

Hospital-onset Clostridium difficile infections (CDIs) have a considerable clinical and economic impact on patients and payers. Quantifying the economic impact of CDIs can guide treatment strategies. However, previous studies have generally focused on acute care hospitals, and few have included cost estimates from non-acute care hospitals such as long-term care facilities.

AIM

This study aimed to quantify the hospital-onset CDI-attributable inpatient expenditures and length-of-stay durations in all healthcare institutions that provide inpatient care (including acute and non-acute care) in Japan.

METHODS

Using national-level insurance claims data, we analyzed patients who had been hospitalized between April 2010 and December 2016. CDI cases were identified and matched with non-CDI controls using hospitalization year, treating hospital, age, sex, surgical procedure, comorbidities, and main diagnoses. Through multivariable regression analyses, we estimated the CDI-attributable inpatient expenditures (2016 US dollars) and length-of-stay durations (days) while adjusting for variations in factors such as patient characteristics, comorbidities, surgery, prescribed antibiotic, geographic region, and hospitalization year. We also analyzed the CDI-attributable inpatient expenditures and length-of-stay durations according to hospital type (acute care and rehabilitation/long-term care).

RESULTS

The analysis was conducted using 3768 matched pairs. Overall, CDI-attributable inpatient expenditures and length-of-stay durations were US$3213 and 11.96 days, respectively. Rehabilitation/long-term care hospitals had substantially higher inpatient expenditures and longer hospitalizations than acute care hospitals.

CONCLUSION

This study quantified the hospital-onset CDI-attributable inpatient expenditures and hospitalizations in both acute and non-acute care hospitals. The inclusion of non-acute care hospitals provides a more accurate representation of the economic burden of CDIs.

Gastrointestinal Graft-versus-Host Disease Is a Risk Factor for Postengraftment Bloodstream Infection in Allogeneic Hematopoietic Stem Cell Transplant Recipients

Bloodstream infection (BSI) is a well-known cause of morbidity and mortality in allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients. Here, we conducted a retrospective study to assess the morbidity, etiology, risk factors, and outcomes of BSI in the postengraftment period (PE-BSI) after allo-HSCT. Forty-three of 316 patients (13.6%) developed 57 PE-BSI episodes, in which 62 pathogens were isolated: Gram-positive bacteria, gram-negative bacteria, and fungi, respectively, accounted for 54.8%, 35.5%, and 9.7% of the isolates. Multivariate analysis revealed methylprednisolone use for graft-versus-host disease (GVHD) prophylaxis (odds ratio [OR], 6.49; 95% confidence interval [CI], 1.49 to 28.2; P = .013) and acute gastrointestinal GVHD (GI-GVHD) (OR, 8.82; 95% CI, 3.99 to 19.5; P < .0001) as risk factors for developing PE-BSI. This finding suggested that GI-GVHD increases the risk of bacterial translocation and subsequent septicemia. Moreover, among patients with GI-GVHD, insufficient response to corticosteroids, presumably related to an intestinal dysbiosis, significantly correlated with this complication. Patients with PE-BSI presented worse outcome compared with those without (3-year overall survival, 47.0% versus 18.6%; P < .001). Close microbiologic monitoring for BSIs and minimizing intestinal dysbiosis may be crucial to break the vicious cycle between GI-GVHD and bacteremia and to improve transplant outcomes especially in patients who require additional immunosuppressants.

Current epidemiology, genetic evolution and clinical impact of extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae

The worldwide spread of extended-spectrum β-lactamase (ESBL)-producing bacteria, particularly Escherichia coli and Klebsiella pneumoniae, is a critical concern for the development of therapies against multidrug-resistant bacteria. Since the 2000s, detection rates of CTX-M types ESBL-producing E. coli in the community have been high, possibly contributing to their nosocomial detection. Various factors, such as environmental sources, food animals, and international travel, accelerate the global ESBL spread in the community. The dramatic dissemination of ESBLs in the community is associated with the relatively recent emergence of CTX-M-15-producing ST131 E. coli clones, which often carry many other antibiotic resistance genes (including quinolone). The usefulness of β-lactam/β-lactamase inhibitor, particularly, piperacillin/tazobactam, has been considered as a carbapenem-sparing regimen for ESBL infections, although the global trend of AmpC β-lactamase-producing bacteria should be monitored carefully. Careful therapeutic selection and continued surveillance for the detection of multidrug-resistant bacteria are required.

Invasive meningococcal disease due to a non-capsulated Neisseria meningitidis strain in a patient with IgG4-related disease

Background

Invasive Meningococcal Disease (IMD) is a rare and critical disease in Japan. Most of these cases are caused by capsulated Neisseria meningitidis strains. Non-capsulated (non-typable) strains are considered relatively low-pathogenic and can colonize in the nasopharynx of healthy children and young adults. As far as could be ascertained, only twelve IMD cases due to non-capsulated strains have been reported in the literature. No clear risk factors could be identified in a literature review (unknown or immunocompetent, seven cases; C6 deficiency, three cases).

Case presentation

We report a Japanese male taxi driver with bacteremia and meningitis due to non-capsulated N. meningitidis. He had a fever and shaking chills. Ceftriaxone was administered, and the patient finally recovered. During the clinical course, relative adrenal insufficiency occurred and was treated with hydrocortisone. A hidden co-morbidity, immunoglobulin G4 (IgG4)-related disease, was revealed in the past surgical history (a resection of bilateral orbital tumors), which included symptoms (swelling lachrymal glands and lymph nodes), elevated IgG4, immunoglobulin E, and hypocomplementemia. He recovered finally and no recurrence was observed.

Conclusions

Our IMD case is the first reported in Japan, where IMD is not considered pandemic. The patient had a history of IgG4-related disease, although we could not establish a clear relationship between the patient’s IMD and co-morbidity. A collection of further clinical cases might establish the risk factors and characteristics of IMD that could be caused by this neglected pathogen, non-capsulated N. meningitidis.

Incomplete recovery of the fecal flora of hematological patients with neutropenia and repeated fluoroquinolone prophylaxis

Background

Routine fluoroquinolone prophylaxis in neutropenic patients with hematological malignancies is still controversial, because of antibiotic resistance concerns. The recovery of the fecal microbiota to the initial composition in patients receiving multiple courses of quinolone prophylaxis and repeated chemotherapy has not been evaluated.

Methods

We prospectively examined the changes in the fecal bacterial composition before and after levofloxacin prophylaxis. A sequential observation of bacterial resistance in patients receiving multiple prophylactic courses was also conducted.

Results

In this trial, 68 cases, including (35 with the first course and 33 with the second and subsequent courses) were registered. The disappearance of quinolone-susceptible (QS) Entero-bacteriaceae and dominant emergence of quinolone-resistant (QR) coagulase negative staphylococci (CNS) and QR Enterococci were observed after the first prophylaxis. The detection of QS Enterobacteriaceae was recovered before the second and subsequent courses to a level of the initial composition (28/35 samples, 80.0% before the first course vs 23/33 samples, 69.7% before the second and subsequent courses, P=0.41). In contrast, the detection rate of QR CNS and Enterococci significantly increased at the second and subsequent courses, even before prophylaxis (8/35 samples, 22.9% before the first course vs 20/33 samples, 60.6% before the second and subsequent courses, P=0.003). The incomplete recovery of the initial bacterial composition was associated with a prophylactic interval of within 30 days. Of the patients receiving multiple prophylactic courses, six had QR Escherichia coli, including extended-spectrum β-lactamase (ESBL) producers, at the first course, and four (66.3%) of the six patients had persistent detection of QR E. coli at the second course.

Conclusion

In patients receiving multiple courses of prophylactic quinolone, along with a common chemotherapy schedule, newly emergent resistant bacteria could be frequently persistent in their fecal flora.

Helicobacter cinaedi Bacteremia Mimicking a Flare of Systemic Lupus Erythematosus

A 40-year-old woman with systemic lupus erythematosus (SLE) presented with high-grade fever and severe thrombocytopenia. Acalculous cholecystitis and thrombocytopenia were initially suspected to be complicated with SLE and vasculitis. Contrary to our expectation, however, the patient was finally diagnosed with Helicobacter cinaedi bacteremia. SLE patients show various symptoms, especially when their condition is complicated with vasculitis, which mimics H. cinaedi bacteremia. It is therefore difficult to provide a definite diagnosis. Physicians should be mindful of the presence of H. cinaedi infection.

[Disseminated Cryptococcosis with Eosinophilia and Elevated IgE in a Non-HIV-infected Patient]

In general, disseminated cryptococcosis usually occurs among immunocompromised patients, especially those with cell-mediated immunodeficiency, such as HIV-infected patients. We present herein a rare case of an apparently immunocompetent 33-year-old woman who developed disseminated cryptococcal diseases, which included meningitis and pneumonia with eosinophilia, and pulmonary tuberculosis during her disease course. Pneumonia with a diffuse micronodular pattern, immediately followed by meningitis, was diagnosed as disseminated cryptococcosis, because of the presence of yeast-like-fungi demonstrated by transbronchial lung biopsy and a positive cerebrospinal fluid (CSF) culture. In addition, the pneumonia exhibited eosinophilia in the peripheral blood and bronchoalveolar lavage fluid. Re-exacerbation of the pneumonia occurred approximately 3 weeks after onset, along with a sputum culture positive for Mycobacterium tuberculosis. Administration of anti-tuberculosis drugs resulted in recovery from the pulmonary tuberculosis. The treatment of cryptococcal meningitis was initiated using a standard induction regimen;however, an unrecovered status, highlighted by elevated CSF pressure, persisted. Finally, full recovery was induced by the addition of flucytosine treatment (100 mg/kg/day) and repeated daily via lumbar puncture. The allergic condition of this patient may have contributed to the onset of disseminated cryptococcosis.

[Bilateral Granulomatous Renal Masses after Intravesical BCG Therapy for Non-muscle-invasive Bladder Cancer and Carcinoma in Situ of the Upper Urinary Tract: A Case Study]

Bacillus Calmette-Guèrin (BCG) is commonly used not only as an infant vaccination, but also as a treatment of and prophylaxis to prevent recurrence in the management of non-muscle-invasive bladder cancer. However, the use of "live" BCG is sometimes complicated by associated infection. We present a case study of a 77-year-old man who developed bilateral renal masses after intravesical BCG therapy was initiated in November 2013, following transurethral resection of non-muscle-invasive bladder cancer. After four courses of BCG (Japan strain, 80 mg per treatment) instillations, a computed tomography examination for febrile episodes showed multiple bilateral renal masses, accompanied by a histological finding of a granulomatous reaction. An acid fast bacterium was cultured from only urine among blood, urine, and microscopic samples. Using the cultured strain, BCG infection was confirmed by the specific gene deletion pattern based on allele-specific polymerase chain reaction analysis. Anti-tuberculosis treatment, including isoniazid (300 mg/day), rifampicin (600 mg/day), and ethambutol (1,000 mg/day), was started for the BCG-related renal granuloma in February 2014. After 3 months, antibiotic therapy was discontinued owing to severe appetite loss, though the masses remained solid. No rapid growth has been detected after anti-BCG therapy. Intravesical BCG therapy is recommended worldwide as one of standard treatments for non-muscle-invasive bladder cancer. We should closely observe patients undergoing this approach for emerging BCG complications.

Decreased secretion of Paneth cell α-defensins in graft-versus-host disease

BACKGROUND

Intestinal microbial ecology is actively regulated by Paneth cell-derived antimicrobial peptides, α-defensins. Graft-versus-host disease (GVHD) is a major complication of allogeneic hematopoietic stem cell transplantation (SCT). We previously demonstrated that Paneth cells are targeted by GVHD, and their expression of antimicrobial peptide α-defensins is impaired, leading to a loss of physiological diversity among the microflora and development of bloodstream infection. Herein, we evaluated whether fecal levels of α-defensins could be surrogate marker of intestinal dysbiosis.

METHODS

We directly measured α-defensin cryptdin-1 (Crp1) in fecal pellets of mice with GVHD by using a novel enzyme-linked immunosorbent assay.

RESULTS

Fecal levels of Crp1 were significantly decreased in mice with GVHD but unchanged in mice without GVHD after SCT. These were correlated with intestinal flora diversity.

CONCLUSION

We demonstrate a link between reduced secretion of Paneth cell α-defensins and dysbiosis of intestinal flora in GVHD. Fecal levels of α-defensins could be surrogate markers for intestinal microbial homeostasis.