鎌田 啓佑

Genetic epidemiological analysis of mobile genetic elements, such as plasmids, has rarely been carried out in Mycobacterium abscessus, regardless of its usefulness in speculating the historical contact between bacteria. In this study, through whole genome sequencing analysis of M. abscessus isolated from the same patient, we identified three plasmids (pMAB625-1, pMAB625-2, and pMAB625-3) that were not found in the type strain ATCC 19977. We conducted an in silico analysis to investigate the distribution of previously identified plasmids, including the pMAB625 plasmids, in M. abscessus isolated from 462 clinical specimens worldwide. pMAB625-3 was the most prevalent plasmid, detected in 11.5% (53/462) of isolates. Furthermore, phylogenetic tree analysis revealed that these plasmids transferred beyond regions and subspecies and acquired unique mutations. These results indicate that the transmission of plasmids increases the genomic diversity in M. abscessus, and plasmid epidemiology is useful for estimating the historical contact between bacteria.

Nontuberculous mycobacteria are rare but serious pathogens in peritoneal dialysis (PD)-associated infections. Mycobacterium abscessus (M. abscessus) is usually resistant to standard anti-tuberculosis drugs. Macrolide antibiotics are key drugs for treating M. abscessus, but macrolide-resistant strains pose particular challenges, and an optimal antimicrobial treatment strategy or duration has not been established for M. abscessus PD-associated infections. We report a case of a 63-year-old man on PD who developed persistent purulent discharge from his PD catheter exit site. Skin swab culture identified macrolide-resistant M. abscessus, with imaging confirming inflammation along the catheter tunnel. These findings led to the diagnosis of M. abscessus PD catheter tunnel infection, with peritonitis excluded. Initial management included early catheter removal, extensive surgical debridement, and 6 weeks of combination antibiotic therapy, including imipenem-cilastatin, amikacin, and clarithromycin, achieving clinical cure. However, the infection recurred after 5 months, necessitating retreatment with debridement and an antibiotic regimen including imipenem-cilastatin, amikacin, azithromycin, and clofazimine for 4 weeks, followed by a continuation regimen with amikacin, clofazimine, and sitafloxacin for 4 months. This approach achieved sustained clinical cure without recurrence at 14 months of follow-up. Based on a literature review of 67 cases of M. abscessus PD-associated infections, all six cases treated with clofazimine achieved clinical cure, but there were no reports on cases of macrolide-resistant M. abscessus treated with clofazimine. Our case represents the first successful clofazimine treatment of macrolide-resistant M. abscessus PD-associated infection, demonstrating clofazimine as a potentially effective oral antibiotic option in combination therapy, particularly in macrolide-resistant cases with limited therapeutic options.

PURPOSE: Amikacin (AMK) is a widely used therapeutic drug monitoring (TDM)-recommended treatment for nontuberculous mycobacterial pulmonary disease (NTM-PD). However, its optimal dosage and TDM target remain unclear. In this study, we aimed to clarify the relationship between AMK exposure, ototoxicity, and efficacy. METHODS: Patients with NTM-PD treated with AMK at Fukujuji Hospital were retrospectively included in this study. The correlation between AMK exposure, measured by peak and trough levels and the area under the concentration-time curve (AUC), ototoxicity, and culture conversion was analyzed using the Mann-Whitney U test and Cox regression analysis. A population pharmacokinetic/pharmacodynamic (PPK/PD) model was developed to predict ototoxicity using TDM measurements. RESULTS: A total of 185 patients were enrolled. The median AMK dose and observation period were 500 (interquartile range [IQR], 500-600) mg/day and 45.8 (IQR, 31.3-76.5) months, respectively. Ototoxicity and culture conversion were observed in 39% and 54% of the enrolled patients, respectively, after initiating AMK. The median time to the development of ototoxicity was 69 (IQR; 43-97) days. Neither ototoxicity nor culture conversion was associated with pharmacokinetic parameter of AMK exposure, including its minimum inhibitory concentration. However, the cumulative AUC was significantly higher in patients who developed ototoxicity (P < 0.001) than in those without ototoxicity. The developed PPK/PD model enabled calculation of cumulative AUC from TDM data and prediction of ototoxicity onset. CONCLUSION: Cumulative AMK exposure was associated with ototoxicity, and our findings allow prediction of ototoxicity onset using AMK TDM data.

Mycobacterium abscessus is a rapidly growing nontuberculous mycobacterium that causes extrapulmonary infections, including surgical site infections. Mycobacterium abscessus subsp. abscessus (MAA) frequently develops macrolide resistance, resulting in difficult-to-treat infections. Recently, surgical site infections caused by MAAs after cosmetic surgeries have become a notable concern, particularly as the number of cosmetic surgery clinics in Japan continues to increase. Therefore, vigilance for MAA infections following cosmetic procedures is necessary. However, reports on the treatment of macrolide-resistant MAA are limited. We report a case of surgical site infection following cosmetic surgery caused by macrolide-resistant MAA. A 47-year-old woman developed subcutaneous erythema, induration, and fistula formation several months after a thread lift procedure. Exudate culture revealed MAA harboring a full-length erm41 gene associated with inducible macrolide resistance, and susceptibility testing confirmed macrolide resistance. Treatment was initiated with combination antimicrobial therapy, including imipenem/cilastatin, amikacin, and tigecycline for 4 weeks, followed by clofazimine and sitafloxacin for 11 months as maintenance therapy. Local debridement was performed; however, complete removal of the threaded material was not feasible because thread had dissolved. After 12 months of treatment, the fistula closed, and no recurrence occurred during follow-up. This case highlights the importance of considering MAA in surgical site infections following cosmetic surgery and suggests that individualized combination antimicrobial therapy based on susceptibility testing may lead to successful outcomes in macrolide-resistant extrapulmonary MAA.

Mycobacterium mageritense is a species of rapidly growing mycobacteria (RGM) found in environmental sources, possibly causing skin, soft tissue, and intravascular device infections. We encountered a case of prostatic abscess caused by M. mageritense that developed three months after transurethral resection of a bladder tumor. The patient was treated with antibiotics and underwent radical cystectomy. Prostatic abscesses due to RGM are rare, but may sometimes be overlooked. Mycobacterial cultures may be helpful in the diagnosis of culture-negative prostatic abscesses following these procedures.

INTRODUCTION: Early antibiotic treatment failure (EATF) is a clinically important concept but remains underrecognized among frontline physicians. Moreover, no validated prediction models currently exist that specifically target EATF in patients with bacteremia. The present study aims to develop and internally validate a clinical prediction model for EATF in hospitalized adults with bacteremia. METHODS: This multicenter retrospective cohort study included adult inpatients with bacteremia from the Japan Bacteremia Inpatient Cohort Association (JA-BICA), conducted across eight community hospitals in Japan from 2018 to 2022. Based on review results, we defined EATF as an outcome that included changes in antibiotics and advanced treatment after 72 hours of admission. Using 28 candidate variables from previous studies, models, and clinical expertise, we developed our model through backward elimination based on the Akaike Information Criterion. After constructing the score model, discrimination was assessed using the area under the curve (AUC), while calibration was evaluated using a plot. Internal validation used the bootstrap method to assess AUC and overfitting. RESULTS: Among the 1,084 eligible patients, 388 experienced EATF. The model included abnormal white blood cell count, low serum albumin, occlusive lesions, transfer admission, and oxygen therapy. Internal validation demonstrated an AUC of 0.66, 95% confidence interval (0.62, 0.69), and a calibration slope of 1.01. CONCLUSIONS: Although the model's discrimination was modest, this study highlights the importance of EATF as a clinical outcome and demonstrates the inherent difficulty of developing predictive models for bacteremia. External validation is warranted.

OBJECTIVES: The incidence of nontuberculous mycobacteria (NTM) infections has increased globally. We describe clinical characteristics and outcomes of extrapulmonary NTM disease. METHODS: This multicenter retrospective study included adult patients with extrapulmonary NTM disease at five Japanese tertiary hospitals (2012-2020), confirmed by culture or polymerase chain reaction tests from non-pulmonary specimens. Clinical characteristics, antimicrobial therapy, source control, treatment outcomes, and mortality were evaluated. RESULTS: Seventy patients were included: 49 with rapidly growing mycobacteria (RGM) and 21 with slowly growing mycobacteria (SGM) infections. Median age was 70; 52.9% were male. Prosthetic devices were present in 38.6% of cases, more frequent in RGM than SGM (51% vs. 10%). Antimicrobials were administered to 70.0%, and 62.9% underwent source control. Treatment duration was longer for SGM (435 vs. 132 days), particularly for bone, joint, and disseminated infections. Cure/improvement occurred in 53 patients (75.7%), with similar outcomes for RGM and SGM. Among RGM infections, lack of source control in device-related cases was associated with poor treatment outcomes. Fifteen patients died during the observation period; two were NTM-related. CONCLUSIONS: Most extrapulmonary NTM cases respond to antimicrobial therapy and source control. RGM infections involving prosthetic devices without source control remain challenging, warranting further research into optimized management.

Although the incidence of AMK-resistant MAC-PD is suspected to have increased, limited data are available on AMK-resistant MAC-PD. This study evaluated the risk factors associated with AMK resistance, the molecular characteristics of the AMK-resistant isolates, and treatment outcomes of the patients with AMK-resistant MAC-PD. This retrospective case-control study included 73 patients with severe and refractory MAC-PD who had a history of aminoglycoside (AMG) drug use. Patients with initial and repeat AMK minimum inhibitory concentration≥64 μg·mL⁻¹were classified as AMK resistance. To clarify the clinical outcomes and prognosis, an observational study was conducted. Twenty-one patients with AMK resistance (AMK resistance group) and 52 controls (AMK susceptible group) were analyzed. In all cases of AMK resistance where previous isolates were available, the AMK MICs were elevated compared to the levels prior to AMG administration. In the multivariate analysis of risk factors, clarithromycin resistance (odds ratio [OR]: 6.31; 95% confidence interval [CI]: 1.68–23.7 and &gt;12 months of total duration of AMG use (OR: 4.69; 95% CI: 1.09–20.2) were identified as independent risk factors for AMK resistance. Twelve out of 21 AMK-resistant isolates (57%) were found to have mutations in therrsregion. There was a significant difference between the AMK-resistant and AMK-susceptible groups in terms of worsening outcomes, including the introduction of home oxygen therapy (38%versus12%; p=0.01) and 3-year mortality (33%versus10%; p=0.02). Better management strategies for patients with severe and refractory MAC-PD are crucial. This includes placing a strong emphasis on preventing AMK resistance.

&lt;sec&gt;&lt;title&gt;BACKGROUND&lt;/title&gt;Detection of Mycobacterium tuberculosis (MTB) in bioaerosols derived from patients with active pulmonary TB is a potential alternative diagnostic method for patients with presumed TB who cannot expectorate sputum.&lt;/sec&gt;&lt;sec&gt;&lt;title&gt;OBJECTIVE&lt;/title&gt;To assess the efficacy of a bioaerosol particle collection method to capture MTB and diagnose TB.&lt;/sec&gt;&lt;sec&gt;&lt;title&gt;METHODS&lt;/title&gt;A mask-like filter holder (3D mask) with a water-soluble gelatine filter (GF) and one containing a water-insoluble polypropylene filter (PPF) were prepared. Eligible patients wore the 3D mask with GF or PPF within 3 days of starting anti-TB drugs. The GF and PPF filters were collected after 2 and 8 h. DNA was extracted from the filter samples and tested using loop-mediated isothermal amplification (LAMP).&lt;/sec&gt;&lt;sec&gt;&lt;title&gt;RESULTS&lt;/title&gt;Filter samples were collected from 57 and 20 patients with and without active pulmonary TB, respectively. The GF and PPF sensitivity was 76.2% and 83.3%, respectively. The specificity of both methods was 100%. Of the 57 patients diagnosed with non-expectorated sputum samples, including suction phlegm, gastric lavage, and bronchial lavage fluid, 55.6% and 50.0% were positive by GF and PPF, respectively.&lt;/sec&gt;&lt;sec&gt;&lt;title&gt;CONCLUSION&lt;/title&gt;We present a 3D mask filter sampling method for exhaled bioaerosol particles that can be used in clinical practice to diagnose patients with presumed TB.&lt;/sec&gt;

UNLABELLED: Non-tuberculosis mycobacteria (NTM), particularly Mycobacterium abscessus subsp. abscessus (M. abscessus), are increasingly being recognized as etiological agents of NTM pulmonary disease. However, treatment options for M. abscessus are limited owing to their natural resistance to most antibiotics, including β-lactams. M. abscessus produces a class A β-lactamase, whose activity is inhibited by cyclic boronic acid β-lactamase inhibitors. We aimed to evaluate the in vitro effects of xeruborbactam, a cyclic boronic acid β-lactamase inhibitor, against M. abscessus when combined with five β-lactams (amoxicillin, tebipenem, cefdinir, cefuroxime, and cefoxitin). The drug susceptibilities of 43 M. abscessus clinical isolates obtained from 43 patients between August 2005 and May 2014 were tested. The MIC results for each β-lactam with or without 4 µg/mL xeruborbactam were examined. Xeruborbactam lowered the MIC90 values of tebipenem, amoxicillin, cefuroxime, and cefdinir by 5, ≥4, 3, and 3 dilutions, respectively. The MIC90 values of cefoxitin without xeruborbactam were 32 µg/mL and did not change upon the addition of xeruborbactam. The lowest MIC90 value was obtained for tebipenem with xeruborbactam. Almost all isolates had an MIC of 4 µg/mL; one isolate had an MIC of 2 µg/mL. With respect to the susceptibility to the same family drug, the number of susceptible isolates increased from 1/43 (2%) to 43/43 (100%) for tebipenem with xeruborbactam. Combining tebipenem and xeruborbactam could be considered an effective all-oral regimen that benefits outpatient treatment of M. abscessus pulmonary disease. IMPORTANCE: Mycobacterium abscessus subsp. abscessus (M. abscessus) disease is treated in two phases; injectable drugs for initial followed by others for continuation. There is a need to develop all-oral treatment methods for M. abscessus infection, especially in the continuation phase. However, treatment options for M. abscessus are limited owing to their natural resistance to most antibiotics. This is the first report to evaluate the in vitro effects of xeruborbactam, a cyclic boronic acid β-lactamase inhibitor capable of inhibiting the class A β-lactamase produced by M. abscessus, against 43 M. abscessus clinical isolates when combined with five β-lactam antibiotics. Xeruborbactam lowered the MIC90 values of tebipenem by five dilutions, and the number of susceptible isolates increased from 1/43 (2%) to 43/43 (100%). We showed that the tebipenem-xeruborbactam combination might be of interest to explore further as a potentially effective oral regimen for outpatient treatment of M. abscessus pulmonary disease.

BACKGROUND: Mycobacterium abscessus subsp. massiliense (MMA) comprises a group of non-tuberculous, rapidly growing mycobacteria. Although MMA can cause pulmonary diseases, surgical site infections, and disseminated diseases, aortic endograft infection has not been reported. Here, we describe the first case of aortic endograft infection caused by MMA. CASE PRESENTATION: Two months after stent-graft insertion for an abdominal aortic aneurysm, an 85-year-old man was admitted with fever and abdominal pain and was diagnosed with aortic endograft infection. Despite 14 days of meropenem and vancomycin intravenous administration, periaortic fluid pooling increased as compared to that before antibiotic administration. The abscess was drained, and fluorescent acid-fast staining of the abscess fluid revealed bacilli. We conducted genetic tests on the genes hsp65, rpoB, and sodA, performed Whole Genome Sequencing (WGS), and identified the organism as MMA. Intravenous imipenem-cilastatin (IPM/CS), amikacin (AMK), and oral clarithromycin (CAM) were administered. After 2 months, oral CAM and sitafloxacin were administered because the abscess had decreased in size. However, after 6 weeks, the abscess increased in size again. Antimicrobial susceptibility testing of the drainage fluid from the abscess resulted in the isolation of an MMA strain that had acquired resistance to CAM. Intravenous IPM/CS, AMK, and oral linezolid were added to the treatment regimen along with oral CAM and STFX. However, he was not fully cured and died 6 months later. Neither the full-length erythromycin ribosome methyltransferase (erm)(41) gene nor the rrl or rpIV gene mutations were found by Sanger sequencing in the pre- and post-treatment strains. Whole-genome sequence analysis of the post-treatment strain revealed mutations in genes with no previous reports of association with macrolide resistance. CONCLUSIONS: Aortic endograft infection caused by MMA strain is extremely rare; nonetheless, MMA should be suspected as the causative microorganism when broad-spectrum antimicrobials are ineffective.

BACKGROUND: Previous SARS-CoV-2 infection and vaccination, coupled with the rapid evolution of SARS-CoV-2 variants, have modified COVID-19 clinical manifestations. We aimed to characterise the clinical symptoms of COVID-19 individuals in omicron BA.2 and BA.5 Japanese pandemic periods to identify omicron and subvariant associations between symptoms, immune status, and clinical outcomes. METHODS: In this registry-based observational study, individuals registered in Sapporo's web-based COVID-19 information system entered 12 pre-selected symptoms, days since symptom onset, vaccination history, SARS-CoV-2 infection history, and background. Eligibility criteria included symptomatic individuals who tested positive for SARS-CoV-2 (PCR or antigen test), and individuals who were not tested for SARS-CoV-2 but developed new symptoms after a household member tested positive for SARS-CoV-2. Symptom prevalence, variables associated with symptoms, and symptoms associated with progression to severe disease were analysed. FINDINGS: Data were collected and analysed between April 25 and Sept 25, 2022. For 157 861 omicron-infected symptomatic individuals, cough was the most common symptom (99 032 [62·7%] patients), followed by sore throat (95 838 [60·7%] patients), nasal discharge (69 968 [44·3%] patients), and fever (61 218 [38·8%] patients). Omicron BA.5 infection was associated with a higher prevalence of systemic symptoms than BA.2 in vaccinated and unvaccinated individuals (adjusted odds ratio [OR] for fever: 2·18 [95% CI 2·12-2·25]). Omicron breakthrough-infected individuals with three or more vaccinations or previous infection were less likely to exhibit systemic symptoms (fever 0·50 [0·49-0·51]), but more likely to exhibit upper respiratory symptoms (sore throat 1·33 [1·29-1·36]; nasal discharge 1·84 [1·80-1·89]). Infected older individuals (≥65 years) had lower odds for all symptoms. However, when symptoms were manifest, systemic symptoms were associated with increased odds for severe disease (dyspnoea 3·01 [1·84-4·91]; fever 2·93 [1·89-4·52]), whereas upper respiratory symptoms were associated with decreased odds (sore throat 0·38 [0·24-0·63]; nasal discharge 0·48 [0·28-0·81]). INTERPRETATION: Host immunological status, omicron subvariant, and age were associated with a spectrum of COVID-19 symptoms and outcomes. BA.5 produced a higher systemic symptom prevalence than BA.2. Vaccination and previous infection reduced systemic symptom prevalence and improved outcomes but increased upper respiratory tract symptom prevalence. Systemic, but not upper respiratory, symptoms in older people heralded severe disease. Our findings could serve as a practical guide to use COVID-19 symptoms to appropriately modify health-care strategies and predict clinical outcomes for older patients with omicron infections. FUNDING: Japan Agency for Medical Research and Development.

The clinical importance of Mycobacterium abscessus species (MABS) infections has been increasing. However, the standard treatment regimens recommended in the current guidelines often result in unfavorable outcomes. Therefore, we investigated the in vitro activity of omadacycline (OMC), a novel tetracycline, against MABS to explore its potential as a novel therapeutic option. The drug susceptibilities of 40 Mycobacterium abscessus subsp. abscessus (Mab) clinical strains obtained from the sputum of 40 patients from January 2005 to May 2014 were investigated. The MIC results for OMC, amikacin (AMK), clarithromycin (CLR), clofazimine (CLO), imipenem (IPM), rifabutin (RFB), and tedizolid (TZD) alone and their combined effects (with OMC) were examined using the checkerboard method. Additionally, we studied the differences in the effectiveness of the antibiotic combinations based on the colony morphotype of Mab. The MIC50 and MIC90 of OMC alone were 2 and 4 μg/mL, respectively. The combinations of OMC with AMK, CLR, CLO, IPM, RFB, and TZD showed synergy against 17.5%, 75.8%, 25.0%, 21.1%, 76.9%, and 34.4% of the strains, respectively. Additionally, OMC combined with CLO (47.1% versus 9.5%, P = 0.023) or TZD (60.0% versus 12.5%, P = 0.009) showed significantly higher synergy against strains with rough morphotypes than those with smooth morphotypes. In conclusion, the checkerboard analyses revealed that the synergistic effects of OMC were observed most frequently with RFB, followed by CLR, TZD, CLO, IPM, and AMK. Furthermore, OMC tended to be more effective against rough-morphotype Mab strains.

BACKGROUND: Previous SARS-CoV-2 infection and vaccination, coupled to rapid evolution of SARS-CoV-2 variants, have modified COVID-19 clinical manifestations. We characterized clinical symptoms of COVID-19 individuals in omicron BA.2 and BA.5 Japanese pandemic periods to identify omicron and subvariant associations between symptoms, immune status, and clinical outcomes. METHODS: Individuals registered in Sapporo's web-based COVID-19 information system entered 12 pre-selected symptoms, days since symptom onset, vaccination history, SARS-CoV-2 infection history, and background. Symptom frequencies, variables associated with symptoms, and symptoms associated with progression to severe disease were analysed. RESULTS: For all omicron-infected individuals, cough was the most common symptom (62.7%), followed by sore throat (60.7%), nasal discharge (44.3%), and fever (38.8%). Omicron BA.5 infection was associated with a higher symptom burden than BA.2 in vaccinated and unvaccinated individuals. Omicron breakthrough-infected individuals with ≥ 3 vaccinations or previous infection were less likely to exhibit systemic symptoms, but more likely to exhibit upper respiratory symptoms. Infected elderly individuals had lower odds for all symptoms, but, when symptoms were manifest, systemic symptoms were associated with an increased risk, whereas upper respiratory symptoms with a decreased risk, of severe disease. CONCLUSION: Host immunological status, omicron subvariant, and age were associated with a spectrum of COVID-19 symptoms and outcomes. BA.5 produced a greater symptom burden than BA.2. Vaccination and prior infection mitigated systemic symptoms and improved outcomes, but increased upper respiratory tract symptom burden. Systemic, but not upper respiratory, symptoms in the elderly heralded severe disease.

BACKGROUND: Tuberculosis (TB) continues to be the leading cause of death for people living with HIV/AIDS (PLHIV), and HIV is the strongest known risk factor for progression to active TB disease for persons with latent TB infection (LTBI). Screening for active TB and LTBI, and TB preventive therapy (TPT) is recommended, however, clinical practices regarding LTBI screening for HIV positive population have not been uniform, resulting in low rates of LTBI screening and TPT uptake, in both low and high TB-burden countries. We sought to explore the practices and attitudes towards TB and LTBI screening in PLHIV among HIV physicians in Japan. METHODS: We conducted a cross-sectional survey whereby an on-line questionnaire was administered to physicians who are currently, or have the experience of, providing care and treatment for PLHIV in Japan. RESULTS: The questionnaire was sent to a total of 83 physicians, of which 59 responded (response rate; 71.1%). 52.5% (31/59) conducted routine screening and 44.0% (26/59) conducted selectively screening for active TB among HIV/AIDS patients. As for LTBI, 54.2% (32/59) conducted routine screening and 35.6% (21/59) conducted selective screening for LTBI among PLHIV. "T-SPOT only" was the most frequently used method of screening (n = 33), followed by "QFT only" (n = 11). Criteria for LTBI screening included TB burden in the country of birth of the patient, previous contact with a TB patient, and CD4+ cell count. 83.1% (49/59) either "always" or "selectively" offered TPT to PLHIV diagnosed with LTBI, and among the 49 respondents who did provide TPT, 77.6% (38/49) chose 9-months isoniazid as their first choice. None chose regimen including rifampicin. CONCLUSIONS: Our study revealed that practices regarding TB and LTBI screening and treatment for PLHIV among HIV physicians were mixed and not necessarily in accordance with the various published guidelines. Building and disseminating scientific evidence that takes into consideration the local epidemiology of TB and HIV in Japan is urgently needed to assist physicians make decisions.

Immunomodulators (tocilizumab/baricitinib) improve outcomes of coronavirus disease (COVID-19) patients, but the synergistic effect of remdesivir is unknown. The effect of combination therapy with remdesivir, immunomodulators, and standard treatment in COVID-19 patients was investigated. This retrospective, single-center study included COVID-19 patients who were treated with tocilizumab or baricitinib. The severity of respiratory status in the two groups on day 14 and day 28 and the duration to respiratory recovery in both groups were compared, and the effect of remdesivir use on respiratory status was examined in a multivariate analysis. Ninety-eight patients received tocilizumab or baricitinib; among them, 72 used remdesivir (remdesivir group) and 26 did not (control group). The remdesivir group achieved faster respiratory recovery than the control group (median 11 days vs. 21 days, p=0.033), faster weaning from supplemental oxygen (HR 2.54, 95% CI 1.14-5.66, p=0.021). Age, body mass index, diabetes mellitus, and time from onset to oxygen administration were independent prognostic factors. The remdesivir group achieved better severity level at days 14 and 28 (p=0.033 and 0.003, respectively) and greater improvement from baseline severity (p=0.047 and 0.018, respectively). Remdesivir combination therapy did not prolong survival (HR 0.31, 95% CI 0.04-2.16, p=0.23). Among severely ill COVID-19 patients who received immunomodulator, remdesivir contributed to a shorter respiratory recovery time and better respiratory status at days 14 and 28. Concomitant remdesivir with immunomodulators and standard treatment may provide additional benefit in improving respiratory status of COVID-19 patients. This article is protected by copyright. All rights reserved.

Background and Objectives: Tocilizumab and baricitinib have been observed to improve the outcomes of patients with coronavirus disease 2019 (COVID-19). However, a comparative evaluation of these drugs has not been performed. Materials and Methods: A retrospective, single-center study was conducted using the data of COVID-19 patients admitted to Hokkaido University hospital between April 2020 and September 2021, who were treated with tocilizumab or baricitinib. The clinical characteristics of the patients who received tocilizumab were compared to those of patients who received baricitinib. Univariate and multivariate logistic regression analyses of the outcomes of all-cause mortality and improvement in respiratory status were performed. The development of secondary infection events was analyzed using the Kaplan-Meier method and the log-rank test. Results: Of the 459 patients hospitalized with COVID-19 during the study, 64 received tocilizumab treatment and 34 baricitinib treatment, and those 98 patients were included in the study. Most patients were treated with concomitant steroids and exhibited the same severity level at the initiation of drug treatment. When compared to each other, neither tocilizumab nor baricitinib use were associated with all-cause mortality or improvement in respiratory status within 28 days from drug administration. Conclusions: Age, chronic renal disease and early administration of TCZ or BRT from the onset of COVID-19 were independent prognostic factors for all-cause mortality, whereas anti-viral drug use and the severity of COVID-19 at baseline were associated with an improvement in respiratory status. Secondary infection-free survival rates of patients treated with tocilizumab and those treated with baricitinib did not significantly differ. The results suggest that both tocilizumab and baricitinib could be clinically equivalent agents of choice in treatment of COVID-19.

We present three cases with an atypical clinical course of organizing pneumonia (OP) secondary to COVID-19. Three patients were discharged with satisfactory improvement after standard steroid therapy for COVID-19. Shortly after the completion of treatment, the patients experienced a flare-up of symptoms. Imaging results showed new lesions in the lungs. Transbronchial lung cryobiopsy showed histological findings consistent with OP in all cases. Steroids were administered, and a good therapeutic response was observed. This report is the first to describe pathologically confirmed OP that developed after recovery from COVID-19. Careful follow-up is advisable for patients who have recovered from COVID-19.

<title>Abstract</title><sec><title>Objective</title><italic>Mycobacterium tuberculosis</italic> (Mtb) H37Ra strain has been reported to rapidly enter the viable but non-culturable (VBNC) state following treatment with an NADH oxidase inhibitor (diphenyleneiodonium [DPI]) and to be resuscitated by fetal bovine serum (FBS). However, the mechanism underlying FBS-induced resuscitation is currently unclear. We tried to reveal the underlying mechanism of FBS-induced resuscitation using <italic>M. tuberculosis</italic> H37Rv. Methods: First, we evaluated the effect of DPI on culturability, viability and changes of cellular phenotypes toward H37Rv. Secondly, we measured the resuscitation-promoting effects of human serum albumin, egg-white albumin, N-acetyl-<italic>L</italic>-cysteine, and D-mannitol in DPI-induced VBNC cells, as antioxidative agents have been reported to be key molecules for resuscitation of other microbes. We also evaluated the effect of inhibition of cAMP production and protein kinase A on BSA-induced resuscitation. </sec><sec><title>Results</title>DPI treatment successfully induced a VBNC state in H37Rv, resulting in a low proportion of culturable cells, loss of acid-fastness and lipid-accumulation but a high proportion of viable cells. Not only FBS but also bovine serum albumin (BSA) alone could resuscitate H37Rv. Contrary to our expectation, only human serum albumin had a similar resuscitative effect to BSA. The inhibition of adenylyl cyclase by SQ22536 did not have a significant effect on resuscitation; however, the inhibition of protein kinase A by H89 strongly suppressed the BSA-induced resuscitation. </sec><sec><title>Conclusion</title>DPI-induced VBNC Mtb cells may be resuscitated via the activation of protein kinase A-dependent processes through interaction with BSA. </sec>

BACKGROUND: The third wave of the COVID-19 epidemic in the island of Hokkaido, the second largest island in Japan, began abruptly in October 2020. METHODS: We conducted a phylodynamic analysis of the SARS-CoV-2 genome sequences obtained from tertiary medical centers in the Greater Tokyo Area and Sapporo, the largest city in the island of Hokkaido, and genome sequences published by GISAID, an international SARS-CoV-2 genome database. We also analyzed the statistics on the person-nights of travelers in the island of Hokkaido from the Greater Tokyo Area in 2019 versus 2020. RESULTS: At least eight sub-lineages belonging to the B.1.1.214 lineage were introduced to the island of Hokkaido from the island of Honshu, the mainland of Japan from late July to November 2020, during the governmental travel promotion program. Five of the eight sub-lineages originated from the Greater Tokyo Area. Comparison of the monthly ratios of the person-nights of travelers in the island of Hokkaido from the Greater Tokyo Area in 2019 and 2020 revealed that the highest value occurred in October 2020. CONCLUSION: We contend that the Japanese governmental travel promotion program contributed to the introduction of the B.1.1.214 sub-lineages from the main island of Honshu to the island of Hokkaido, and drove the third wave in Hokkaido, even if we are unable to establish the causality.

BACKGROUND: The impact of the outbreak of COVID-19 on the work of respiratory physicians in Japan has not yet been evaluated. The study investigates the impact of the outbreak on respiratory physicians' work over time and identifies problems to be addressed in the future. METHODS: We conducted a web-based survey of respiratory physicians in 848 institutions. The survey comprised 32 questions and four sections: Survey 1 (April 20, 2020), Survey 2 (May 27, 2020), Survey 3 (August 31, 2020), and Survey 4 (December 4, 2020). RESULTS: The mean survey response rate was 24.9%, and 502 facilities (59.2%) participated in at least one survey. The proportion of facilities that could perform PCR tests for diagnosis and more than 20 tests per day gradually increased. The percentage capable of managing extracorporeal membrane oxygenation (ECMO) or more than five ventilators did not increase over time. The proportion that reported work overload of 150% or more, stress associated with lack of personal protective equipment (PPE), and harassment or stigma in the surrounding community did not sufficiently improve. CONCLUSION: While there was an improvement in expanding the examination system and medical cooperation in the community, there was no indication of enhancement of the critical care management system. The overwork of respiratory physicians, lack of PPE, and harassment and stigma related to COVID-19 did not sufficiently improve and need to be addressed urgently.

This study aimed to identify effective treatments against rapidly growing mycobacteria (RGM) infections by investigating the minimum inhibitory concentrations (MIC) of 24 antimicrobial agents and their molecular mechanisms of resistance. In total, 509 clinical RGM isolates were identified by analyzing the sequences of three housekeeping genes (hsp65, rpoB, and sodA), and their susceptibilities to 24 antimicrobial agents were tested. We also performed sequencing analysis of antimicrobial resistance genes (rrl, rrs, gyrA, and gyrB). To identify Mycobacteroides abscessus group subspecies, we performed PCR-based typing and determined the sequevar of erm(41). We identified 15 RGM species, most of which were susceptible to amikacin and linezolid. Among these species, arbekacin and sitafloxacin had the lowest MIC among the same class of antimicrobials. The MIC of rifabutin for M. abscessus subsp. abscessus (MAB) was lower than that for M. abscessus subsp. massiliense (MMA). The proportion of MAB isolates with MIC ≤ 2 mg/L for rifabutin was significantly higher than that of MMA [MAB: 50/178 (28.1%) vs. MMA: 23/130 (17.7%); p = 0.041]. In summary, our study revealed the antimicrobial susceptibility profile of 15 RGM species isolated in Japan and indicated that arbekacin, sitafloxacin, and rifabutin may be possible therapeutic options for RGM infections.

Infectious diseases caused by nontuberculous mycobacteria (NTM) are increasingly becoming a major global problem. Additionally, Mycobacteroides abscessus subsp. abscessus (MAB) infections are refractory to macrolides. This study was conducted to investigate the epidemiology of rapidly growing mycobacteria (RGM) species isolated from clinical specimens in Japan and assess differences in the regional distribution of lower respiratory specimens (LRS)- and non-lower respiratory specimens (NLRS)-derived species. 532 strains (427 LRS, 92 NLRS and 15 unknown specimens) were isolated in nine areas of Japan. We collected 418 specimens from Bio Medical Laboratories (BML), Inc., and 114 specimens from 45 hospitals in Japan. Their epidemiological differences were examined according to the specimen type, region, and climate. Fifteen species were identified. The proportion of M. abscessus group (MAG) strains was significantly lower in NLRS than in LRS (35.9% vs. 68.4%). The proportion of MAG strains was higher in northern Japan than in other regions (83.7% vs. 60.5%). Variations in strain abundance among RGM species was evident in regions with a mean annual temperature below 15 °C. We conclude that the proportions of MAG strains differed between NLRS and LRS in Japan. In addition, the mean annual temperature likely influenced the distribution of RGM species.

We provide the details of the successful management of a patient with active Cushing's disease complicated with coronavirus disease 2019 (COVID-19) pneumonia. The patient was a 27-year-old Japanese female healthcare worker who was scheduled to undergo pituitary surgery for Cushing's disease. She had been in close contact with an undiagnosed patient infected with COVID-19 and then developed COVID-19 pneumonia. Despite a lack of known risk factors associated with severe COVID-19 infection, the patient's dyspnea worsened and her respiratory condition deteriorated, as indicated by the need for 7 L/min oxygen supply by mask to maintain her oxygen saturation at >90%. Medical treatment was initiated to control hypercortisolism by the 'block and replace' regimen using steroidogenesis inhibitors and hydrocortisone. The COVID-19 pneumonia improved with multi-modal treatment including antiviral therapy. One month later, after a negative severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) test result and with appropriate protection against virus transmission to medical staff in the operating room and daily medical care nurses, trans-sphenoidal surgery was performed by our highly experienced pituitary surgeon. One month after the surgery, the patient's basal ACTH and cortisol levels and urinary free cortisol were all under the detection limit. Surgical remission was expected. Since hypercortisolism due to active Cushing's disease may worsen a COVID-19 infection, multi-disciplinary management that includes appropriate and prompt treatment strategies is mandatory in such cases.

BACKGROUND: Mycolicibacterium fortuitum is a species of the rapidly growing mycobacteria that can cause pulmonary infection. It is susceptible to multiple antibiotics both in vitro and in clinical practice, so that any combination of susceptible drugs is effective. However, we encountered a case of infection due to fluoroquinolone-resistant M. fortuitum. In this study, we report the case and describe the mechanism of resistance. CASE PRESENTATION: A 65-year-old man with a history of total gastrectomy and immunosuppressant treatment for rheumatoid arthritis developed a recurrence of pulmonary infection caused by M. fortuitum. He was treated with clarithromycin and levofloxacin as a first-line treatment, based on the favorable susceptibility at that time. After recurrence, a high minimum inhibitory concentration to fluoroquinolones was detected. DNA sequencing of the pathogen showed the substitution of serine for tryptophan at residue 83 in the gyrA gene. He was successfully treated with a combination of other antibiotics. CONCLUSION: This is the first report on the treatment of fluoroquinolone-resistant M. fortuitum and investigation of the mechanism of resistance. We suggest that the susceptibility test remains effective for determining the next line of treatment after a pathogen has acquired resistance, and resistance to fluoroquinolones in M. fortuitum can be attributed to a single change of amino acid.

BACKGROUND: No clinical scoring system has yet been established to estimate the likelihood of coronavirus disease (COVID-19) and determine the suitability of diagnostic testing in suspected COVID-19 patients. METHODS: This was a single-center, retrospective, observational study of patients with suspected COVID-19 and confirmed COVID-19. Patient background, clinical course, laboratory and computed tomography (CT) findings, and the presence of alternative diagnoses were evaluated. Clinical risk scores were developed based on clinical differences between patients with and without COVID-19. RESULTS: Among 110 patients suspected of having COVID-19, 60.9% underwent polymerase chain reaction (PCR) testing based on the judgment of physicians. Two patients were found to have COVID-19. The clinical characteristics of 108 non-COVID-19 patients were compared with those of 23 confirmed COVID-19 patients. Patients with COVID-19 were more likely to have a history of high-risk exposures and an abnormal sense of taste and smell. The COVID-19 group had significantly higher rates of subnormal white blood cell counts, lower eosinophil counts, and lower procalcitonin levels than the non-COVID-19 group. When blood test results, CT findings, and the presence of alternative diagnoses were scored on an 11-point scale (i.e., "COVID-19 Clinical Risk Score"), the COVID-19 group scored significantly higher than the non-COVID-19 group, more than four points in the COVID-19 group. All non-COVID patients who did not undergo PCR had a score of 4 or less. CONCLUSIONS: The COVID-19 Clinical Risk Score may enable the risk classification of patients suspected of having COVID-19 and can help in decision-making in clinical practice, including appropriateness of diagnostic testing. Further studies and prospective validation with an increased sample size are required.

Rapid detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical for the diagnosis of coronavirus disease 2019 (COVID-19) and preventing the spread of the virus. A novel detection kit - the 2019 Novel Coronavirus Detection Kit (nCoV-DK) - halves the detection time by eliminating the steps of RNA extraction and purification. We evaluated the concordance between the nCoV-DK and direct PCR. The virus was detected in 53/71 specimens (74.6%) by direct PCR and in 55/71 specimens (77.5%) by nCoV-DK; the overall concordance rate was 94.4%: 95.2% for nasopharyngeal swab, 95.5% for saliva, and 85.7% for sputum. The nCoV-DK test effectively detects SARS-CoV-2 in all types of sample including saliva, while reducing the time required for detection, labor, and the risk of human error.

We report a case of clinically diagnosed secondary organizing pneumonia (SOP) associated with coronavirus disease 2019 (COVID-19). A 70-year-old woman who had been diagnosed with COVID-19 was admitted to Hokkaido University Hospital. Although her fever, cough, dyspnea, and serum C-reactive protein levels improved, she developed rapidly progressive respiratory failure and computed tomography revealed the development of bilateral lung consolidation. Her dyspnea was relieved, and her oxygenation levels and radiological findings improved after commencing corticosteroid treatment. Blood biomarkers for interstitial lung disease, Krebs von den Lungen-6 (KL-6) and surfactant protein D (SP-D), showed different responses during the clinical course of her disease. Evaluation of serial changes in levels of KL-6 and SP-D may help diagnose and monitor COVID-19-associated organizing pneumonia (OP). Clinicians should be aware that SOP can develop in response to COVID-19 and that these patients may benefit from the use of steroids.

Staphylococcus argenteus TWCC 58113 was isolated from a specimen from a 12-year-old boy with purulent lymphadenitis. The S. argenteus TWCC 58113 genome was completely sequenced. The TWCC 58113 chromosome was 2,761,442 bp in size with a GC content of 32.44%. S. argenteus TWCC 58113 was found to harbor two plasmids.

Staphylococcus argenteus is a novel species separated from a strain of coagulase-positive, non-pigmented S. aureus. Although S. argenteus has been reported to occur globally, multilocus sequence type (ST) 2250 is mainly found in Northeastern Thailand. Because conventional biochemical testing misidentifies this pathogen as S. aureus, multilocus sequence typing (MLST) or nucA sequencing is recommended to distinguish between S. argenteus and S. auereus. The patient was a previously healthy 12-year-old boy who was admitted because of right inguinal lymphadenitis and cellulitis. Although intravenous cefazolin was administered, his lymphadenitis worsened and formed an abscess on day 6 of hospitalization. Incision and drainage were performed on day 7 of hospitalization. Cefazolin was changed to oral cefaclor, and the patient was successfully treated over a period of 5 weeks. No recurrence was observed throughout 12-months of follow-up. He had a history of right axillary lymph node abscess 2 months before this admission, which was successfully treated with incision, drainage, and antibiotic therapy. He has lived in Japan since birth and never traveled abroad. He had no opportunity to interact with foreigners. His immune function, especially neutrophil function, was tested and we did not find any dysfunction. First, methicillin-sensitive S. aureus was misidentified from the abscess culture. Subsequently, the causative agent was re-identified as S. argenteus ST2250 based on MLST. To our knowledge, this is the first case of S. argenteus ST2250 infection in Japan. This pathogen should be taken into consideration in the diagnosis if the patient has atypical non-pigmented S. aureus.

BACKGROUND: Gemella bergeri is one of the nine species of the genus Gemella and is relatively difficult to identify. We herein describe the first case of septic shock due to a Gemella bergeri coinfection with Eikenella corrodens. CASE PRESENTATION: A 44-year-old Asian man with a medical history of IgG4-related ophthalmic disease who was prescribed corticosteroids (prednisolone) presented to our hospital with dyspnea. On arrival, he was in shock, and a purpuric eruption was noted on both legs. Contrast enhanced computed tomography showed fluid retention at the right maxillary sinus, left lung ground glass opacity, and bilateral lung irregular opacities without cavitation. Owing to suspected septic shock, fluid resuscitation and a high dose of vasopressors were started. In addition, meropenem, clindamycin, and vancomycin were administered. Repeat computed tomography confirmed left internal jugular and vertebral vein thrombosis. Following this, the patient was diagnosed with Lemierre's syndrome. Furthermore, he went into shock again on day 6 of hospitalization. Additional soft tissue infections were suspected; therefore, bilateral below the knee amputations were performed for source control. Cultures of the exudates from skin lesions and histopathological samples did not identify any pathogens, and histopathological findings showed arterial thrombosis; therefore it was concluded that the second time shock was associated with purpura fulminans. Following this, his general status improved. He was transferred to another hospital for rehabilitation. The blood culture isolates were identified as Gemella bergeri and Eikenella corrodens. Gemella bergeri was identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry and confirmed by 16S rRNA gene sequencing later. The primary focus of the infection was thought to be in the right maxillary sinus, because the resolution of the fluid retention was confirmed by repeat computed tomography. CONCLUSIONS: Gemella bergeri can be the causative pathogen of septic shock. If this pathogen cannot be identified manually or through commercial phenotypic methods, 16S rRNA gene sequencing should be considered.

Mycobacterium abscessus is one of the most pathogenic and chemotherapy-resistant rapidly growing mycobacteria. This Mycobacterium should always be considered as a possible cause of chronic otitis media in children, and treatment might be challenging because of its resistance to multiple antibiotics. There are no reports describing the therapeutic use of tigecycline for the treatment of chronic otitis media caused by M. abscessus. A 10-year-old boy was referred to Tokyo Metropolitan Children's Medical Center with a 7-year history of recurrent otitis media despite treatment with antibiotics and ventilation tubes. Cultures of the otorrhea yielded Mycobacterium abscessus spp. massiliense, and it showed multiple and high-level resistance. The boy required surgery and underwent initial treatment with clarithromycin, amikacin, and tigecycline for 4 weeks. He experienced emesis as a side-effect of tigecycline, which was well controlled with ondansetron. He was treated successfully with 3 months of subsequent oral clarithromycin and linezolid. This is the first pediatric case of chronic otitis media caused by M. abscessus treated with a tigecycline-containing regimen. Although the therapeutic use of tigecycline remains controversial, especially in the pediatric population, it can be an acceptable option in the treatment of chronic otitis media caused by M. abscessus.