Hypothermic circulatory arrest at 20 ℃ does not deteriorate coagulopathy compared to 28 ℃ in a pig model.

It is believed that a lower temperature setting of hypothermic circulatory arrest (HCA) in thoracic aortic surgery causes coagulopathy, resulting in excessive bleeding. However, experimental studies that eliminate clinical factors are lacking. The objective of this study is to investigate the influence of the temperature setting of HCA on coagulation in a pig model. Ten pigs were divided into the following two groups: moderate temperature at 28 °C (group M, n = 5) or lower temperature at 20 °C (group L, n = 5). Two hours of HCA during a total of 4 h of cardiopulmonary bypass (CPB) were performed. Blood samples were obtained at the beginning (T1) and the end (T2) of the surgery, and coagulation capability was analyzed through standard laboratory tests (SLTs) and rotational thromboelastometry (ROTEM). In SLTs, hemoglobin, fibrinogen, platelet count, prothrombin time, and activated partial thromboplastin time were analyzed. In ROTEM analyses, clotting time and clot formation time of EXTEM, maximum clot firmness (MCF), and maximum clot elasticity (MCE) of EXTEM and FIBTEM were analyzed. Fibrinogen decreased significantly in both groups (group M, p = 0.008; group L, p = 0.0175) at T2, and FIBTEM MCF and MCE also decreased at T2. There were no differences regarding changes in parameters of SLTs and ROTEM between groups. CPB decreases coagulation capacity, contributed by fibrinogen. However, a lower temperature setting of HCA at 20 °C for 2 h did not significantly affect coagulopathy compared to that of HCA at 28 °C after re-warming to 37 °C.

Super-Elderly Case of Acute Lower Limb Ischemia Treated with Indigo Aspiration System in Japan.

The Indigo Aspiration System (Penumbra Ltd., Alameda, CA, USA), a catheter-based device intended for the endovascular removal of clots from peripheral arteries and veins, was launched in Japan to treat acute limb ischemia after the cessation of urokinase sales. The initial application of this system in Japan was on a 96-year-old male patient. He was diagnosed with acute lower limb ischemia, which was caused by an embolism from a left common iliac artery aneurysm. The treatment significantly enhanced the perfusion to his left foot. This case report elaborates on the patient's treatment experience and discusses the indications for using the device.

Stent Graft Migration Due to Structural Failure Nine Months After Thoracic Endovascular Aortic Repair Using Valiant Navion.

Objective: This report presents a case of stent graft migration that was suspected to have occurred due to failure of the Valiant Navion device (Medtronic Inc., Santa Rosa, CA, USA). This case was rare because the broken device was removed from the living patient and examined directly. Case report: A 69 year old man who had previously undergone thoracic endovascular aortic repair (TEVAR) with arch vessel debranching (axillo-axillary bypass with left common carotid artery bypass) for distal arch aneurysm experienced stent graft (SG) migration 9 months after the primary surgery. Total arch replacement was performed, and the migrated SG was removed. The broken stent ring and suture seams were then found. The patient was discharged on post-operative day 41 and followed up in the outpatient department. Discussion: Stent graft migration is a relatively rare complication after TEVAR and associated with type I or III endoleak, which can result in serious outcomes. In this case, it was suspected that migration had occurred after TEVAR due to structural failure of the Valiant Navion device; similar cases have been reported previously, suggesting a structural problem with the device. Therefore, other patients treated with the Navion device in the future will require careful follow up.

Aortic endograft infection by Mycobacterium abscessus subsp. massiliense with acquired clarithromycin resistance: a case report.

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.

Venous Screening Activities at the Site of Hokkaido East Iburi Earthquake: Report from the Result of Venous Screening in Preventive Awareness Activities.

After previous earthquakes, high prevalence of cardiovascular diseases including venous thromboembolism (VTE) has been reported. We performed venous screening at the site of Hokkaido East Iburi Earthquake which happened at 6th September 2018. VTE screening using ultrasound sonography was performed for total 7 days at Atsuma town, Mukawa town and Abira town (total 9 shelters). Deep vein thrombosis (DVT) was found in 19 of 195 evacuees (9.7%), including 8 fresh thrombus cases (4.1%). On multivariable analysis of evacuees and shelter environment factors, systolic blood pressure, use of cardboard bed and toilet environment were significant predictor of DVT. Introduction and setting-up of cardboard beds were found as an important shelter environment factor. (This is secondary publication from Jpn J Phlebol 2021; 32(1): 5-10.).

Associations of COVID-19 symptoms with omicron subvariants BA.2 and BA.5, host status, and clinical outcomes in Japan: a registry-based observational study.

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.

In Vitro Synergistic Effects of Omadacycline with Other Antimicrobial Agents against Mycobacterium abscessus.

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.

A Novel Graft Route by Passage under the Achilles Tendon in Paramalleolar Distal Bypass Using the Small Saphenous Vein.

A 77-year-old man with diabetes presented to our hospital because of left toe gangrene, requiring infrapopliteal revascularization. The patient was on hemodialysis for renal dysfunction. The great saphenous veins had been used for a previous coronary artery bypass. Hence, the small saphenous vein was applied in a popliteal-to-distal posterior tibial artery bypass. The vein graft was passed under the Achilles tendon to reduce graft length, preventing external compression around the ankle. We performed minor amputation and provided negative pressure wound therapy to promote ulcer healing. The wounds healed entirely after two months.

Associations of COVID-19 Symptoms with Omicron Subvariants BA.2 and BA.5, Host Status, and Clinical Outcomes: A Registry-Based Observational Study in Sapporo, Japan.

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.

Outcomes of Infrapopliteal Bypass for Chronic Limb-Threatening Ischemia are Worse in Renal Transplant Patients than in Hemodialysis-Dependent Patients.

BACKGROUND: Comparisons of distal bypass outcomes between hemodialysis-dependent (HD) and renal transplant (RT) patients have been reported, but the influences of immunosuppressive therapy on the outcomes remain unclear because of the limited number of RT patients who underwent distal bypass or cohort heterogenicity. We compared outcomes of distal bypass for chronic limb-threatening ischemia (CLTI) with homogenous ischemic limb pathology. METHODS: Between January 2014 and December 2019, we performed 334 infrapopliteal bypass procedures using vein grafts for 275 consecutive CLTI patients with tissue loss. Among them, there were 130 HD patients (47.3%) (163 limbs) and 11 RT patients (4%) (15 limbs), and 30-day mortality, 5-year primary and secondary patency (PP and SP), limb salvage (LS), amputation-free survival rates, and wound healing (WH) status were compared between the HD and RT patient groups. RESULTS: Nine HD patients died within 30 days after surgery (7%), whereas no deaths were observed among the RT patients. Five-year PP and SP rates in the RT group 39% and 41%, which were significantly worse compared to 64% and 82% in the HD group (P < 0.01). Unsuccessful rate of revision surgery including hemodynamically failed grafts after revision reached over 80% in the RT group, which was technically unfeasible pathology for graft salvage (vs. 3% in the HD group), and WH, and LS rates were significantly worse in the RT group. CONCLUSIONS: In comparison with HD patients, RT patients showed a lower LS rate for CLTI. The lower LS rate was associated with a lower SP rate, which was caused by disease progression of distal arteries in the foot.

Practices and attitudes towards tuberculosis and latent tuberculosis infection screening in people living with HIV/AIDS among HIV physicians in Japan.

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.

Combination therapy with remdesivir and immunomodulators improves respiratory status in COVID-19: A retrospective study.

Immunomodulators (tocilizumab/baricitinib) improve outcomes of coronavirus disease 2019 (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 Days 14 and 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 vs. 21 days, p = 0.033), faster weaning from supplemental oxygen (hazard ratio [HR]: 2.54, 95% confidence interval [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.

Comparative Efficacy of Tocilizumab and Baricitinib Administration in COVID-19 Treatment: A Retrospective Cohort Study.

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.

Successful endovascular therapy involving direct puncture for spontaneous internal iliac artery aneurysm rupture.

Neurofibromatosis type 1 (NF-1) is associated with fatal vascular complications. A 40-year-old woman with NF-1 who had previously undergone left iliac artery ligation and femorofemoral bypass grafting for internal iliac artery (IIA) aneurysm rupture was transported to our hospital for the treatment of a newly developed IIA aneurysm. Although endovascular therapy was difficult owing to the previous surgery, we successfully performed embolization of the aneurysm and its feeding vessels via direct percutaneous puncture under ultrasound guidance. Aneurysm enhancement had completely disappeared at 2 months postoperatively. We have reported a novel approach of direct percutaneous puncture for IIA aneurysm embolization in a patient with NF-1.

Delayed-onset Organizing Pneumonia Emerging after Recovery from Coronavirus Disease 2019: A Report of Three Cases Diagnosed Using Transbronchial Cryobiopsy and a Review of the Literature.

We present three cases with an atypical clinical course of organizing pneumonia (OP) secondary to coronavirus disease 2019 (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.

Multiple introductions of SARS-CoV-2 B.1.1.214 lineages from mainland Japan preceded the third wave of the COVID-19 epidemic in Hokkaido.

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.

The effect of the outbreak of COVID-19 on respiratory physicians and healthcare in Japan: Serial nationwide surveys by the Japanese Respiratory Society.

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.

Nationwide surveillance of antimicrobial susceptibility of 509 rapidly growing mycobacteria strains isolated from clinical specimens in Japan.

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.

Mitocryptide-2: Identification of Its Minimum Structure for Specific Activation of FPR2-Possible Receptor Switching from FPR2 to FPR1 by Its Physiological C-terminal Cleavages.

Mitocryptides are a novel family of endogenous neutrophil-activating peptides originating from various mitochondrial proteins. Mitocryptide-2 (MCT-2) is one of such neutrophil-activating peptides, and is produced as an N-formylated pentadecapeptide from mitochondrial cytochrome b. Although MCT-2 is a specific endogenous ligand for formyl peptide receptor 2 (FPR2), the chemical structure within MCT-2 that is responsible for FPR2 activation is still obscure. Here, we demonstrate that the N-terminal heptapeptide structure of MCT-2 with an N-formyl group is the minimum structure that specifically activates FPR2. Moreover, the receptor molecule for MCT-2 is suggested to be shifted from FPR2 to its homolog formyl peptide receptor 1 (FPR1) by the physiological cleavages of its C-terminus. Indeed, N-terminal derivatives of MCT-2 with seven amino acid residues or longer caused an increase of intracellular free Ca2+ concentration in HEK-293 cells expressing FPR2, but not in those expressing FPR1. Those MCT-2 derivatives also induced ß-hexosaminidase secretion in neutrophilic/granulocytic differentiated HL-60 cells via FPR2 activation. In contrast, MCT-2(1-4), an N-terminal tetrapeptide of MCT-2, specifically activated FPR1 to promote those functions. Moreover, MCT-2 was degraded in serum to produce MCT-2(1-4) over time. These findings suggest that MCT-2 is a novel critical factor that not only initiates innate immunity via the specific activation of FPR2, but also promotes delayed responses by the activation of FPR1, which may include resolution and tissue regeneration. The present results also strongly support the necessity of considering the exact chemical structures of activating factors for the investigation of innate immune responses.