櫻井 亜樹

Carbapenemase-producing Enterobacterales (CPEs) are one of the top priority antimicrobial-resistant pathogens. Among CPEs, those producing acquired metallo-β-lactamases (MBLs) are considered particularly problematic as few agents are active against them. Imipenemase (IMP) is the most frequently encountered acquired MBL in Japan, but comprehensive assessment of clinical and microbiological features of IMP-producing Enterobacterales infection remains scarce. Here, we retrospectively evaluated 62 patients who were hospitalized at a university hospital in Japan and had IMP-producing Enterobacterales from a clinical culture. The isolates were either Enterobacter cloacae complex or Klebsiella pneumoniae, and most of them were isolated from sputum. The majority of K. pneumoniae, but not E. cloacae complex isolates, were susceptible to aztreonam. Sequence type (ST) 78 and ST517 were prevalent for E. cloacae complex and K. pneumoniae, respectively, and all isolates carried blaIMP-1. Twenty-four of the patients were deemed infected with IMP-producing Enterobacterales. Among the infected patients, therapy varied and largely consisted of conventional β-lactam agents, fluoroquinolones, or combinations. Three (13%), five (21%), and nine (38%) of them died by days 14, 30, and 90, respectively. While incremental mortality over 90 days was observed in association with underlying comorbidities, active conventional treatment options were available for most patients with IMP-producing Enterobacterales infections, distinguishing them from more multidrug-resistant CPE infections associated with globally common MBLs, such as New Delhi metallo-β-lactamase (NDM) and Verona integron-encoded metallo-β-lactamase (VIM).

OBJECTIVES: Taxonomic assignment based on whole-genome sequencing data facilitates clear demarcation of species within a complex genus. Here, we applied a unique pan-genome phylogenetic method, open reading frame (ORF)-based binarized structure network analysis (OSNA), for taxonomic inference of Aeromonas spp., a complex taxonomic group consisting of 30 species. METHODS: Data from 335 publicly available Aeromonas genomes, including the reference genomes of 30 species, were used to build a phylogenetic tree using OSNA. In OSNA, whole-genome structures are expressed as binary sequences based on the presence or absence of ORFs, and a tree is generated using neighbor-net, a distance-based method for constructing phylogenetic networks from binary sequences. The tree built by OSNA was compared to that constructed by a core-genome single-nucleotide polymorphism (SNP)-based analysis. Furthermore, the orthologous average nucleotide identity (OrthoANI) values of the sequences that clustered in a single clade in the OSNA-based tree were calculated. RESULTS: The phylogenetic tree constructed with OSNA successfully delineated the majority of species of the genus Aeromonas forming conspecific clades for individual species, which was corroborated by OrthoANI values. Moreover, the OSNA-based phylogenetic tree demonstrated high compositional similarity to the core-genome SNP-based phylogenetic tree, supported by the Fowlkes-Mallows index. CONCLUSIONS: We propose that OSNA is a useful tool in predicting the taxonomic classification of complex bacterial genera.

BACKGROUND: The genus Aeromonas is increasingly implicated in human infections, but knowledge of its clinical characteristics and antimicrobial resistance profiles has been limited owing to its complex taxonomy. METHODS: We conducted a multicenter prospective cohort study of patients with Aeromonas infections at hospitals across Japan. Patients were eligible for inclusion if they had an Aeromonas spp. strain in a clinical culture and were considered infected at the culture site. Clinical data were collected, and isolates underwent susceptibility testing and whole-genome sequencing. RESULTS: A total of 144 patients were included. Hepatobiliary infection accounted for a majority of infections (73% [105 of 144]), which mostly occurred in elderly patients with comorbid conditions, including hepatobiliary complications. The all-cause 30-day mortality rate was 10.0% (95% confidence interval, 4.9%-14.8%). By whole-genome sequencing, 141 strains (98%) belonged to 4 Aeromonas species-A caviae, A hydrophila, A veronii, and A dhakensis-with significant intraspecies diversity. A caviae was predominant in all infection sites except skin and soft tissue, for which A hydrophila was the prevailing species. The genes encoding chromosomally mediated class B, C, and D β-lactamases were harbored by 92%-100% of the isolates in a species-specific manner, but they often lacked association with resistance phenotypes. The activity of cefepime was reliable. All isolates of A hydrophila and A dhakensis carried an mcr-3-like colistin resistance gene and showed reduced susceptibility to colistin. CONCLUSIONS: Hepatobiliary tract was the most common infection site of Aeromonas spp., with A caviae being the dominant causative species. The resistance genotype and phenotype were often incongruent for β-lactam agents.

<jats:title>Abstract</jats:title> <jats:sec> <jats:title>Background</jats:title> <jats:p>Carbapenem-resistant bacteria in patients with cancer are concerning due to the high risk of infection and mortality rates; however, the characteristics and prognoses of carbapenem-resistant infections in this population are currently unknown in Japan. We hence investigated the features and outcomes of carbapenem-resistant bacterial infections (CRBI) in patients with cancer in Japan.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>From April 1, 2019, to March 31, 2022, patients with CRBI who either had cancer or no cancer were prospectively enrolled at eight centers as part of the Multi-Drug Resistant Organisms Clinical Research Network (MDRnet). The primary outcome was the 30-day all-cause mortality rates in patients with and without cancer. Two secondary outcomes were evaluated: 1) composite outcomes including mortality, worsening of clinical course after culture collection, intensive care unit stay, intubation, new dialysis from the date of culture collection to the end of antimicrobial therapy, and readmission within 90 days after discharge; and 2) the length of hospital stay after CRBI excluding death.</jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>We included a total of 167 patients, with 66 (39.5%) in the cancer group and 101 (60.5%) in the non-cancer group. The 30-day mortality rates in the cancer and non-cancer groups were 18.2% (12/66) and 14.0% (14/101), respectively (p = 0.45), while the composite outcomes in the cancer and non-cancer groups were 56.1% (37/66) and 43.6% (44/101), respectively (p = 0.12). Average duration of hospitalization was not significantly different between the two groups (cancer group, 44.6 days; non-cancer group, 51.0 days; p = 0.55). Propensity score analysis using inverse probability weighting also showed no significant difference in 30-day mortality and average duration of hospitalization (p = 0.22 and 0.98, respectively); however, the composite outcome was significantly higher in the cancer group than in non-cancer controls (odds ratio, 2.41; 95% confidence interval, 1.11–5.21; p = 0.03).</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusion</jats:title> <jats:p>There was no difference in 30-day mortality rates between the cancer and non-cancer patient groups; however, we found a significant difference in the composite outcome. Patients with cancer who had CRBI experienced a worse clinical course that non-cancer patients.</jats:p> </jats:sec> <jats:sec> <jats:title>Disclosures</jats:title> <jats:p>Masahiro Suzuki, PhD, KANTO Chemical co., inc.: Grant/Research Support Yasufumi Matsumara, MD, PhD, Beckman Coulter: Grant/Research Support|Presicion System Science: Grant/Research Support|Toyobo: Grant/Research Support David van Duin, MD, PhD, Entasis: Advisor/Consultant|Merck: Advisor/Consultant|Merck: Grant/Research Support|Pfizer: Advisor/Consultant|Pfizer: Honoraria|Qpex: Advisor/Consultant|Roche: Advisor/Consultant|Shionogi: Advisor/Consultant|Shionogi: Grant/Research Support|Union: Advisor/Consultant|Utility: Advisor/Consultant Yohei Doi, MD, PhD, bioMerieux: Advisor/Consultant|FujiFilm: Advisor/Consultant|Gilead: Advisor/Consultant|Gilead: Honoraria|GSK: Advisor/Consultant|Meiji Seika Pharma: Advisor/Consultant|Moderna: Advisor/Consultant|Moderna: Honoraria|MSD: Advisor/Consultant|MSD: Honoraria|Shionogi: Advisor/Consultant|Shionogi: Grant/Research Support|Shionogi: Honoraria Sho Saito, MD, PhD, Shionogi &amp; Company, Limited: Grant/Research Support</jats:p> </jats:sec>

<jats:title>Abstract</jats:title> <jats:sec> <jats:title>Background</jats:title> <jats:p>Stenotrophomonas maltophilia has become one of the major gram-negative pathogens causing nosocomial infections. However, comprehensive analysis of the clinical characteristics and molecular epidemiology of patients with S. maltophilia remains limited.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>All patients with a clinical culture growing S. maltophilia were collected from April 2019 to March 2022 through the Multi-Drug Resistant organisms clinical research network (MDRnet), consisting of 12 tertiary care hospitals in Japan. The clinical characteristics, outcomes, antimicrobial susceptibility and molecular epidemiology of cases with S. maltophilia colonization and infection were investigated and compared.</jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>In total, 78 cases, 44 with colonization and 34 with infection, were included. The median age was 72.5 years (IQR: 61–78), and males accounted for 53 cases (67.9%). The most common comorbidity was localized solid malignancy (38.5%). Almost half of the patients (43.6%) were immunosuppressed, and the most common reason was antineoplastic chemotherapy (30.8%). Respiratory tract was the most common site of colonization (86.4%), whereas bacteremia accounted for more than half of infection cases (55.9%). The overall 30-day all-cause mortality rate was 20.5%, which was significantly higher in infection cases than in colonization cases (35.3% vs 9.1%; odds ratio, 5.33; 95% confidence interval, 1.40–25.45). Susceptibility rates to ceftazidime, levofloxacin, minocycline, and sulfamethoxazole-trimethoprim were 14.1%, 65.2%, 87.2%, and 100%, respectively. Multilocus sequence typing of the 78 strains revealed that they belonged to 62 different sequence types (STs), of which 42 were known STs and 36 were novel STs.</jats:p> <jats:p>Kaplan-Meier survival analysis</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusion</jats:title> <jats:p>S. maltophilia frequently colonizes the respiratory tract, and the mortality is significantly higher in infection cases. Sulfamethoxazole-trimethoprim remains active, but susceptibility to levofloxacin appear to be declining. The strains were genetically highly diverse, consistent with the likely environmental origin.</jats:p> </jats:sec> <jats:sec> <jats:title>Disclosures</jats:title> <jats:p>Masahiro Suzuki, PhD, KANTO Chemical co., inc.: Grant/Research Support Sho Saito, MD, PhD, Shionogi &amp; Company, Limited: Grant/Research Support Yasufumi Matsumara, MD, PhD, Beckman Coulter: Grant/Research Support|Presicion System Science: Grant/Research Support|Toyobo: Grant/Research Support David van Duin, MD, PhD, Entasis: Advisor/Consultant|Merck: Advisor/Consultant|Merck: Grant/Research Support|Pfizer: Advisor/Consultant|Pfizer: Honoraria|Qpex: Advisor/Consultant|Roche: Advisor/Consultant|Shionogi: Advisor/Consultant|Shionogi: Grant/Research Support|Union: Advisor/Consultant|Utility: Advisor/Consultant Yohei Doi, MD, PhD, bioMerieux: Advisor/Consultant|FujiFilm: Advisor/Consultant|Gilead: Advisor/Consultant|Gilead: Honoraria|GSK: Advisor/Consultant|Meiji Seika Pharma: Advisor/Consultant|Moderna: Advisor/Consultant|Moderna: Honoraria|MSD: Advisor/Consultant|MSD: Honoraria|Shionogi: Advisor/Consultant|Shionogi: Grant/Research Support|Shionogi: Honoraria</jats:p> </jats:sec>

Cefmetazole is active against extended-spectrum β-lactamase-producing Escherichia coli (ESBLEC) and is a potential candidate for carbapenem-sparing therapy. This multicenter, observational study included patients hospitalized for invasive urinary tract infection due to ESBLEC between March 2020 and November 2021 at 10 facilities in Japan, for whom either cefmetazole or meropenem was initiated as a definitive therapy within 96 h of culture collection and continued for at least 3 d. Outcomes included clinical and microbiological effectiveness, recurrence within 28 d, and all-cause mortality (14 d, 30 d, in-hospital). Outcomes were adjusted for the inverse probability of propensity scores for receiving cefmetazole or meropenem. Eighty-one and forty-six patients were included in the cefmetazole and meropenem groups, respectively. Bacteremia accounted for 43% of the cefmetazole group, and 59% of the meropenem group. The crude clinical effectiveness, 14 d, 30 d, and in-hospital mortality for patients in the cefmetazole and meropenem groups were 96.1% vs 90.9%, 0% vs 2.3%, 0% vs 12.5%, and 2.6% vs 13.3%, respectively. After propensity score adjustment, clinical effectiveness, the risk of in-hospital mortality, and the risk of recurrence were similar between the two groups (P = 0.54, P = 0.10, and P = 0.79, respectively). In all cases with available data (cefmetazole : n = 61, meropenem : n = 22), both drugs were microbiologically effective. In all isolates, blaCTX-M was detected as the extended-spectrum β-lactamase gene. The predominant CTX-M subtype was CTX-M-27 (47.6%). Cefmetazole showed clinical and bacteriological effectiveness comparable to meropenem against invasive urinary tract infection due to ESBLECs.

OBJECTIVES: The increased identification of carbapenem-resistant Pseudomonas aeruginosa (CR-PA) is an ongoing concern. However, information on the evolving antimicrobial resistance profile and molecular epidemiology of CR-PA over time is scarce. Thus, we conducted a cross-sectional analysis to investigate the phenotypic and genotypic characteristics of CR-PA recovered over different time periods, focusing on the isolates exhibiting a ceftolozane/tazobactam resistance phenotype. METHODS: A total of 169 CR-PA isolated from clinical specimens at a single centre in Houston, TX, USA were studied. Among them, 61 isolates collected between 1999 and 2005 were defined as historical strains, and 108 collected between 2017 and 2018 were defined as contemporary strains. Antimicrobial susceptibilities against selected β-lactams was determined. WGS data were used for the identification of antimicrobial resistance determinants and phylogenetic analysis. RESULTS: Non-susceptibility to ceftolozane/tazobactam and ceftazidime/avibactam increased from 2% (1/59) to 17% (18/108) and from 7% (4/59) to 17% (18/108) from the historical to the contemporary collection, respectively. Carbapenemase genes, which were not identified in the historical collection, were harboured by 4.6% (5/108) of the contemporary strains, and the prevalence of ESBL genes also increased from 3.3% (2/61) to 16% (17/108). Genes encoding acquired β-lactamases were largely confined to the high-risk clones. Among ceftolozane/tazobactam-resistant isolates, non-susceptibility to ceftazidime/avibactam, imipenem/relebactam and cefiderocol was observed in 94% (15/16), 56% (9/16) and 12.5% (2/16), respectively. Resistance to ceftolozane/tazobactam and imipenem/relebactam was primarily associated with the presence of exogenous β-lactamases. CONCLUSIONS: Acquisition of exogenous carbapenemases and ESBLs may be a worrisome trend in P. aeruginosa.

BACKGROUND: Ceftolozane/tazobactam is a β-lactam/β-lactamase inhibitor combination with activity against a variety of Gram-negative bacteria, including MDR Pseudomonas aeruginosa. This agent is approved for hospital-acquired and ventilator-associated bacterial pneumonia. However, most real-world outcome data come from small observational cohorts. Thus, we sought to evaluate the utilization of ceftolozane/tazobactam at multiple tertiary hospitals in Houston, TX, USA. METHODS: We conducted a multicentre retrospective study of patients receiving at least 48 h of ceftolozane/tazobactam therapy from January 2016 through to September 2019 at two hospital systems in Houston. Demographic, clinical and microbiological data were collected, including the infecting bacterial isolate, when available. The primary outcome was composite clinical success at hospital discharge. Secondary outcomes included in-hospital mortality and clinical disposition at 14 and 30 days post ceftolozane/tazobactam initiation. Multivariable logistic regression analysis was used to identify predictors of the primary outcome and mortality. Recovered isolates were tested for susceptibility to ceftolozane/tazobactam and underwent WGS. RESULTS: A total of 263 patients were enrolled, and composite clinical success was achieved in 185 patients (70.3%). Severity of illness was the most consistent predictor of clinical success. Combination therapy with ceftolozane/tazobactam and another Gram-negative-active agent was associated with reduced odds of clinical success (OR 0.32, 95% CI 0.16-0.63). Resistance to ceftolozane/tazobactam was noted in 15.4% of isolates available for WGS; mutations in ampC and ftsI were common but did not cluster with a particular ST. CONCLUSIONS: Clinical success rate among this patient cohort treated with ceftolozane/tazobactam was similar compared with previous experiences. Ceftolozane/tazobactam remains an alternative agent for treatment of susceptible isolates of P. aeruginosa.

Mycoplasma hominis is a commensal pathogen normally found in urogenital tract of humans and has been associated with a wide variety of extra-genitourinary infections, such as mediastinitis, bacteremia, and septic arthritis, particularly in immunocompromised patients. Here, we present a case of a 48-year-old male, who had been treated with fingolimod for relapsing multiple sclerosis and presented with fever and right-sided hip pain following total hip arthroplasty. CT scan revealed localized fluid collection in the right quadriceps femoris muscle adjacent to the joint cavity of right hip. The percutaneously aspirated fluid grew M. hominis, which was also isolated from blood culture. With diagnosis of periprosthetic joint infection, the patient underwent surgical debridement with retained prosthesis and was treated with antimicrobial agents. Infected granulation tissues excised from the hip was observed under an electron microscope, which revealed electron-dense rounded structures contained in neutrophils, consistent with Mycoplasma particles. Fingolimod, an immunomodulatory drug that acts on the sphingosine-1-phosphate receptor and prevents the egress of lymphocytes from lymph nodes, might increase host susceptibility to a systemic M. hominis infection.

Although piperacillin-tazobactam (TZP) was shown to be less effective than carbapenems in treating bacteremia due to extended-spectrum β-lactamase-producing (ESBL)-producing organisms in a randomized controlled trial, the fact that many of the causative organisms co-produced inhibitor-resistant OXA-1 along with ESBLs may have influenced the results. In this study, we compared the therapeutic effectiveness of TZP and carbapenem in treating ESBL-producing Escherichia coli bacteremia in areas with low frequency of OXA-1 co-production. Forty patients, 14 in the TZP treatment group and 26 in the carbapenem treatment group, were included in the analysis. There were no significant differences in patient background between the two groups. Urinary tract infection or cholangitis was the source of bacteremia in 26 patients (65%), and the Pitt bacteremia score was zero or one in 35 patients (87.5%). Only four (11.4%) of the 35 causative isolates available for microbiological analysis harbored blaOXA-1, and only three (8.6%) were non-susceptible to TZP. Seventeen (48.6%) isolates carried blaCTX-M-27, none of which carried other β-lactamase genes. No significant difference in the frequency of treatment failure on day 14 of bacteremia was documented between the TZP and carbapenem treatment groups in both the crude analysis and the inverse probability of treatment weighting-adjusted analysis. This study demonstrates that TZP may be a treatment option for non-severe cases of ESBL-producing E. coli bacteremia in areas with low frequency of OXA-1 co-production. IMPORTANCE Although carbapenems are considered the drug of choice for severe infections caused by extended-spectrum β-lactamase-producing (ESBL)-producing organisms, other therapeutic options are being explored to avoid increasing the selective pressure for carbapenem-resistant organisms. In this study, it was suggested that piperacillin-tazobactam may be as effective as carbapenems for the treatment of mild bacteremia caused by ESBL-producing Escherichia coli in areas where OXA-1 co-production by ESBL-producing E. coli is rare. The genetic background of each regional epidemic clone differs even among multidrug-resistant bacteria classified under the same name (e.g., ESBL-producing organisms), resulting in possible differences in the efficacy of therapeutic agents. Exploration of treatment options for multidrug-resistant organisms according to local epidemiology is worthwhile from the perspective of antimicrobial stewardship.

Faropenem (FRPM) is active against extended-spectrum β-lactamase (ESBL)-producing Enterobacterales, but evidence for its efficacy is lacking. This study determined the correlation between the susceptibility by disk diffusion method and the MIC of FRPM for third-generation cephalosporin-resistant Escherichia coli and Klebsiella pneumoniae, and the effectiveness of FRPM for the treatment of urinary tract infection (UTI) caused by these two bacteria in a retrospective cohort analysis. Of the 48 third-generation cephalosporin-resistant clinical isolates tested, 44 isolates produced ESBL, and 8 isolates produced AmpC, including 4 isolates produced both ESBL and AmpC. Thirty-seven isolates had an FRPM MIC of ≤1 mg/L, and seven had an FRPM MIC of 2 mg/L. An FRPM MIC of >2 mg/L was observed with four isolates. In a retrospective cohort analysis, 63 patients with UTI treated with FRPM were identified. All isolates of ESBL-producing E. coli (n = 54) and K. pneumoniae (n = 9) treated with FRPM showed disk diffusion zone diameters larger than 16.0 mm (estimated MIC, 2.2 mg/L). All patients completed the scheduled treatment courses with FRPM, but 28- and 90-day relapses happened in 10 patients (16%) and 16 patients (25%), respectively. No significant risk factors for the 28- and 90-day relapses were found. FRPM can be used according to disk diffusion susceptibility testing in UTI. Further investigations are necessary to assess the clinical breakpoint of FRPM for ESBL-producing Enterobacterales and the candidates most likely to benefit from using FRPM.

Secondary fungal infections are a critical problem that accompany immunosuppressive therapy for severe coronavirus disease 2019 (COVID-19). We report a fatal case of COVID-19 with disseminated mucormycosis diagnosed during autopsy. A 58-year-old man with diabetes was hospitalized for severe COVID-19 and treated with remdesivir, systemic steroids and tocilizumab. Following treatment, he was provided extracorporeal membrane oxygenation support. However, he died of multiple organ failure accompanied by pulmonary and kidney infarction, as revealed by computed tomography. Autopsy revealed that the infarction was caused by thromboangiitis due to mucormycosis in the brain, lungs, heart, liver and kidneys. Therefore, the diagnosis of disseminated mucormycosis was established. Disseminated mucormycosis is a rare complication of COVID-19. Although its early diagnosis is difficult, the disease progresses rapidly. Hence, we propose that immunosuppressive treatment for COVID-19 should be administered with caution considering the risk of developing severe opportunistic infections, such as mucormycosis.

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) can cause a wide variety of infections, ranging from skin and soft tissue infections to life-threatening invasive diseases such as necrotizing pneumonia and infective endocarditis. Here, we present a case of a healthy young female presenting with fever, headache and nausea, who was diagnosed with mitral valve infective endocarditis due to CA-MRSA and whose course was complicated by meningitis and multiple septic emboli. The causative MRSA strain belonged to sequence type 97 and harbored SCCmec Ⅳc but not lukS/F-PV genes. ST97, which is frequently isolated from livestock animals and known as a common lineage of livestock-associated MRSA, may cause invasive infection in the community.

Carbapenemase-producing Escherichia coli sequence type (ST) 648 strains were isolated from two international visitors without previous medical exposure from Southeast Asian countries in a hospital in Japan. One isolate, FUJ80154, carried blaNDM-5 in a complex class 1 integron on an IncFIB/FII plasmid; the other isolate, FUJ80155, carried two copies of blaOXA-48 on the chromosome flanked by IS1R on both sides. The core-genome based-phylogenetic analysis with publicly available genome data of E. coli ST648 carrying blaNDM-5 or blaOXA-48-like demonstrated high genetic similarity between FUJ80154 and NDM-5-prooducing E. coli ST648 strains isolated in South and Southeast Asian countries. On the other hand, no closely related isolates of FUJ80155 were identified. In the absence of prior hospitalization overseas, neither patient had qualified for routine screening of multidrug-resistant organisms, and the isolates were incidentally identified in cultures ordered at the discretion of the treating physician. IMPORTANCE Although patients with history of international hospitalization are often subject to screening for multidrug-resistant organisms, it is unclear whether patients who reside in countries where carbapenemase-producing Enterobacterales (CPE) is endemic but have no history of local hospitalization contribute to the transmission of CPE. In this study, NDM-5-producing and OXA-48-producing Escherichia coli sequence type (ST) 648, a recently recognized high-risk, multidrug-resistant clone, were detected from two overseas visitors without previous medical exposure. The findings of this study suggest that active surveillance culture on admission to hospital may be considered for travelers from countries with endemicity of carbapenem-resistant organisms even without history of local hospitalization and underscore the need to monitor cross-border transmission of high-risk clones, such as carbapenemase-producing E. coli ST648.

INTRODUCTION: Several clinical studies have reported the efficacy of favipiravir in reducing viral load and shortening the duration of symptoms. However, the viability of SARS-CoV-2 in the context of favipiravir therapy and the potential for resistance development is unclear. METHODS: We sequenced SARS-CoV-2 in nasopharyngeal specimens collected from patients who participated in a randomized clinical trial of favipiravir at hospitals across Japan between March and May 2020. Paired genomes were sequenced from those who remained RT-PCR-positive 5-8 days into favipiravir therapy. Daily nasopharyngeal specimens from 69 patients who were RT-PCR-positive at randomization were examined for a cytopathic effect (CPE). RESULTS: Some strains early in the trial belonged to clade 19 B, whereas the majority belonged to clade 20 B. The median time from the disease onset to negative CPE was 9 days. CPE was strongly correlated with the time from disease onset, viral load, age, and male sex. Among 23 patients for whom paired genomes were available, all except one had identical genomes. Two mutations were observed in one patient who received favipiravir, neither in the RdRp gene. CONCLUSIONS: The SARS-CoV-2 genome distribution in this clinical trial conducted in Japan reflected the early influx of strains from China followed by replacement by strains from Europe. CPE was significantly associated with age, male sex, and viral loads but not with favipiravir therapy. There was no evidence of resistance development during favipiravir therapy.

Information regarding the infectivity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in asymptomatic carriers is scarce. In order to determine the duration of infectivity and its correlation with reverse transcription-PCR (RT-PCR) results and time since initial positive PCR test in this population, we evaluated SARS-CoV-2 cell infectivity in nasopharyngeal samples longitudinally obtained from asymptomatic carriers who disembarked from a cruise ship during a COVID-19 outbreak. Of 166 nasopharyngeal samples collected from 39 asymptomatic carriers every 48 h until two consecutive negative PCR test results were obtained, SARS-CoV-2 was successfully isolated from 9 PCR-positive samples which were obtained from 7 persons (18%; 7/39). Viable viruses were isolated predominantly within 7 days after the initial positive PCR test, except for one person who shed viable virus until day 15. The median crossing point (Cp) value of RT-PCR of culture-positive samples was 24.6 (interquartile range [IQR], 20.4 to 25.8; range, 17.9 to 30.3), and Cp values were significantly associated with isolation of viable virus (odds ratio, 0.496; 95% confidence interval [CI], 0.329 to 0.747; P value, 0.001), which was consistent with existing data for symptomatic patients. Genome sequence analysis of SARS-CoV-2 samples consecutively obtained from a person who shed viable virus for 15 days identified the emergence of two novel single nucleotide variants (C8626T transition and C18452T transition) in the sample collected on day 15, with the latter corresponding to an amino acid substitution in nonstructural protein 14. The impact of these mutations on prolonged viable-virus shedding is unclear. These findings underscore the potential role of asymptomatic carriers in transmission.IMPORTANCE A growing number of studies suggest the potential role of asymptomatic SARS-CoV-2 carriers as a major driver of the COVID-19 pandemic; however, virological assessment of asymptomatic infection has largely been limited to reverse transcription-PCR (RT-PCR), which can be persistently positive without necessarily indicating the presence of viable virus (e.g., replication-competent virus). Here, we evaluated the infectivity of asymptomatic SARS-CoV-2 carriers by detecting SARS-CoV-2-induced cytopathic effects on Vero cells using longitudinally obtained nasopharyngeal samples from asymptomatic carriers. We show that asymptomatic carriers can shed viable virus until 7 days after the initial positive PCR test, with one outlier shedding until day 15. The crossing point (Cp) value of RT-PCR was the leading predictive factor for virus viability. These findings provide additional insights into the role of asymptomatic carriers as a source of transmission and highlight the importance of universal source control measures, along with isolation policy for asymptomatic carriers.

We report the first case of disseminated nocardiosis due to trimethoprim/sulfamethoxazole-resistant Nocardia terpenica successfully treated with meropenem and clarithromycin. The patient travelled to Japan from Australia via Southeast Asia, which led to differential diagnoses of multiple lung nodules including miliary tuberculosis and melioidosis as well as nocardiosis. Because of variety of susceptibility depending on the Nocardia species, clinicians need to confirm the species and investigate its susceptibility.

Postmortem lung pathology of a patient in Japan with severe acute respiratory syndrome coronavirus 2 infection showed diffuse alveolar damage as well as bronchopneumonia caused by Streptococcus pneumoniae infection. The distribution of each pathogen and the accompanying histopathology suggested the infections progressed in a mutually exclusive manner within the lung, resulting in fatal respiratory failure.

BACKGROUND: Vagococcal infections are uncommon in humans; there are limited studies on the clinical manifestations, the optimal methods for identifications, and antimicrobial susceptibility testing for vagococcal infections. Here, we have reported a case of Vagococcus fluvialis-induced bacteremia and decubitus ulcer and have systematically reviewed other reported Vagococcus infections. CASE PRESENTATION: A 74-year-old man presented to our emergency department with muscle weakness on his left extremities, dysarthria, and altered mental status along with fever for the past 4 days. Physical examination revealed a decubitus ulcer with foul smelling and yellowish exudative pus on his left chest wall and abdomen, forearm, thigh, and lower leg. He was empirically treated with 2.25 mg of piperacillin/tazobactam every 8 hours and 0.5 g of vancomycin every 24 hours intravenously (IV) for his decubitus ulcer. Vagococcus fluvialis was detected in both aerobic and anaerobic blood cultures (upon admission) using the VITEC 2 GP ID card (bioMérieux) and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). We continued the mentioned IV antimicrobial therapies for 4 weeks following which the patient was transferred to a long-term care facility for further rehabilitation. CONCLUSIONS: To our best knowledge, this is the first literature review of Vagococcus infections in humans. Since it is challenging to distinguish Vagococcus from Enterococcus by a conventional method due to the similarity of its biochemical properties to those of Enterococcus, based on our literature review, 16S rRNA sequencing or analysis of bacterial protein profile using MALDI-TOF MS may be useful for the precise identification.

Penicillin-resistant viridans group streptococci (VGS) infections are an emerging issue in infectious diseases. Here, we present a case of mitral valve infective endocarditis caused by highly penicillin-resistant VGS (minimum inhibitory concentration >4 μg/mL), which was successfully treated with daptomycin. Although the clinical efficacy of daptomycin has not been established, it can be an alternative for the treatment of highly resistant VGS endocarditis.

BACKGROUND: Helicobacter cinaedi is rarely identified as a cause of infected aneurysms; however, the number of reported cases has been increasing over several decades, especially in Japan. We report three cases of aortic aneurysm infected by H. cinaedi that were successfully treated using meropenem plus surgical stent graft replacement or intravascular stenting. Furthermore, we performed a systematic review of the literature regarding aortic aneurysm infected by H. cinaedi. CASE PRESENTATION: We present three rare cases of infected aneurysm caused by H. cinaedi in adults. Blood and tissue cultures and 16S rRNA gene sequencing were used for diagnosis. Two patients underwent urgent surgical stent graft replacement, and the other patient underwent intravascular stenting. All three cases were treated successfully with intravenous meropenem for 4 to 6 weeks. CONCLUSIONS: These cases suggest that although aneurysms infected by H. cinaedi are rare, clinicians should be aware of H. cinaedi as a potential causative pathogen, even in immunocompetent patients. Prolonged incubation periods for blood cultures are necessary for the accurate detection of H. cinaedi.

Background: Several immunochromatographic serological test kits have been developed to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibodies, but their relative performance and potential clinical utility is unclear. Methods: Three commercially available serological test kits were evaluated using 99 serum samples collected from 29 patients diagnosed with coronavirus disease 2019 (COVID-19) and 100 serum samples collected from 100 healthy volunteers in 2017 as negative controls. Results: The specificity of the IgM and IgG antibodies showed comparable results among the three immunochromatographic serological test kits. The specificity for IgM antibody was 98.0%, 98.0%, and 97.0%, and the specificity for IgG antibody was identical among the three kits (99.0%). The IgM antibody-positive rates of the three test kits for samples taken at the early stage of the disease (0-4 days after onset) were consistent with all three kits (18.2%); however, the IgM antibody-positive rates thereafter showed considerable differences among the kits, making it difficult to interpret the kinetics of IgM response against SARS-CoV-2. The IgG antibody-positive rates for samples taken after 13 days of onset were 100.0%, 97.6%, and 97.6%, respectively. Conclusion: There were large differences among the results of the three test kits. Only few cases showed positive results for IgM, suggesting that at least 2 of these kits used in this study were unsuitable for diagnosis of COVID-19. The IgG antibody was positive in almost all samples after 13 days of onset, suggesting that it may be useful for determining infections in the recent past.

Central nervous system aspergillosis is relatively rare and difficult to diagnose. Here, we report a case of 90-year-old man with chronic lymphocytic leukemia who presented with a month-long gradually worsening headache followed by 3 days of low-grade fever associated with altered mental status. Aspergillus meningitis diagnosed using Aspergillus galactomannan antigen in the cerebrospinal fluid and treated with voriconazole. Delayed diagnosis and treatment of Aspergillus meningitis is typically associated with high mortality; therefore, it is imperative to include this disease in the differential diagnoses of subacute meningitis.

A 79-year-old woman with a history of total hysterectomy for cervical cancer with ureterocutaneostomy presented with high fever. She had tenderness and a hard lump around the ureterocutaneostomy site. Computed tomography scan revealed 1.5 cm ureteral calculus in ureterocutaneous fistula (Fig. 1A) associated with bilateral hydronephrosis (Fig. 1B) and we performed a transureteral stent insertion. Blood culture grew methicillin-sensitive Staphylococcus aureus (MSSA), Haemophilus parainfluenzae, Veillonella species and Bacteroides fragilis and urine culture revealed Escherichia coli, MSSA, and Enterococcus faecalis. The patient's clinical signs and symptoms gradually improved with ampicillin/sulbactam. Patients with urinary diversions including ureterocutaneostomy and iliac conduits are at increased risk of urolithiasis (1), which can cause sepsis, pyelonephritis, and renal insufficiency (2). Since most patients become colonized with a multitude of bacteria including Enterobacteriaceae and skin flora such as Staphylococcus aureus and Streptococcus spp., we should empirically treat with broad-spectrum antimicrobials until the culture results are available. Early diagnosis and urological intervention are required because it can be life-threatening with delayed treatment.

Tumbling motility is one of the useful characteristics of Listeria monocytogenes. This can be helpful to identify the causative pathogen along with Gram staining before the confirmatory microbiological examination.

Organizing pneumonia (OP) is a nonspecific response to various forms of lung injury and has been reported in association with several infectious agents. However, little is known about the relationship between OP and chronic pulmonary aspergillosis, and the mechanism of this linkage has not been elucidated. Here, we present a case of chronic pulmonary aspergillosis that led to the development of OP, which was successfully treated with corticosteroid and surgical intervention. In a review of the literature, we aim to highlight the possible relationship between OP and chronic pulmonary aspergillosis.

We evaluated the performance of the Verigene Gram-Negative Blood Culture Nucleic Acid Test (BC-GN; Nanosphere, Northbrook, IL, USA), an automated multiplex assay for rapid identification of positive blood cultures caused by 9 Gram-negative bacteria (GNB) and for detection of 9 genes associated with β-lactam resistance. The BC-GN assay can be performed directly from positive blood cultures with 5 minutes of hands-on and 2 hours of run time per sample. A total of 397 GNB positive blood cultures were analyzed using the BC-GN assay. Of the 397 samples, 295 were simulated samples prepared by inoculating GNB into blood culture bottles, and the remaining were clinical samples from 102 patients with positive blood cultures. Aliquots of the positive blood cultures were tested by the BC-GN assay. The results of bacterial identification between the BC-GN assay and standard laboratory methods were as follows: Acinetobacter spp. (39 isolates for the BC-GN assay/39 for the standard methods), Citrobacter spp. (7/7), Escherichia coli (87/87), Klebsiella oxytoca (13/13), and Proteus spp. (11/11); Enterobacter spp. (29/30); Klebsiella pneumoniae (62/72); Pseudomonas aeruginosa (124/125); and Serratia marcescens (18/21); respectively. From the 102 clinical samples, 104 bacterial species were identified with the BC-GN assay, whereas 110 were identified with the standard methods. The BC-GN assay also detected all β-lactam resistance genes tested (233 genes), including 54 bla(CTX-M), 119 bla(IMP), 8 bla(KPC), 16 bla(NDM), 24 bla(OXA-23), 1 bla(OXA-24/40), 1 bla(OXA-48), 4 bla(OXA-58), and 6 blaVIM. The data shows that the BC-GN assay provides rapid detection of GNB and β-lactam resistance genes in positive blood cultures and has the potential to contributing to optimal patient management by earlier detection of major antimicrobial resistance genes.

We report the case of a patient with pulmonary tuberculosis, whose diagnosis was delayed because of prior treatment with fluoroquinolone and metronidazole. A 35-year-old woman developed productive cough, fever, and back pain, which lasted for 3 weeks before admission to hospital. She had been diagnosed with lower respiratory infection and was treated with garenoxacin mesilate hydrate for 7 days before admission. As her symptoms did not improve, she was referred to our hospital for further evaluation. A chest computed tomography scan revealed confluent consolidation in the right lower lung, predominantly in segment 7, and lung abscess was initially suspected. Since chemotherapy with ceftriaxone and minomycin did not reduce her symptoms, metronidazole was added on day 4. Her symptoms improved dramatically and she was discharged on day 15. Metronidazole was given for a total of 3 weeks, and 2 weeks after discontinuation of metronidazole, she presented with recurrent chest pain and was diagnosed with active pulmonary tuberculosis. In addition to the atypical imaging findings in this patient, the use of chemotherapeutics such as garenoxacin mesilate hydrate and metronidazole, which have anti-tuberculosis effects, meant that the diagnosis of tuberculosis was complicated and hence delayed. We should keep in mind that some general chemotherapy agents, including linezolid, also have anti-tuberculosis effects and may cause similar problems with diagnosis.

INTRODUCTION: Granulomatous lesions are commonly encountered abnormalities in pulmonary pathology, and often pose a diagnostic challenge. We report an unusual case of granulomatous lung disease with uncommon characteristics, which developed following Epstein-Barr-virus-induced mononucleosis and new-onset systemic lupus erythematosus. We aim to highlight a diagnostic approach for the condition and to raise awareness of the possibility of it being related to the immunological reaction caused by Epstein-Barr virus infection. CASE PRESENTATION: A 36-year-old Japanese man, who had been diagnosed with Epstein-Barr-virus-induced infectious mononucleosis, new-onset systemic lupus erythematosus, and secondary Sjögren's syndrome three weeks previously, presented to our facility with fever and diffuse pulmonary infiltrates. A computed tomography scan of the chest revealed multiple small nodules in both lungs. Fiberoptic bronchoscopy with bronchoalveolar lavage revealed lymphocytosis with predominance of T lymphocytes. A histological examination of a lung biopsy taken during video-assisted thoracic surgery showed randomly distributed tiny granulomatous lesions with infiltration of eosinophils. The differential diagnoses included hypersensitivity pneumonitis, sarcoidosis, and pulmonary involvement of Crohn's disease, systemic lupus erythematosus, and Sjögren's syndrome, but the clinical and pathological findings were not consistent with any of these. Our patient's condition did not improve; therefore, prednisolone therapy was started because of the possibility of specific immunological reactions associated with Epstein-Barr virus infection. After steroid treatment, our patient showed radiological and clinical improvement. CONCLUSIONS: To the best of our knowledge, this is the first case of a patient developing randomly distributed multiple granulomatous lung lesions with eosinophilic infiltrates after Epstein-Barr virus infection and systemic lupus erythematosus. On the basis of our data, we hypothesize that Epstein-Barr virus infection altered the immune response of our predisposed patient and contributed to the pathogenesis of the lung lesions. Our patient's clinical response to steroid treatment was excellent.

Nitrofurazone, a veterinary antimicrobial drug, causes mammary and ovarian tumors in animals. We investigated the mechanisms of carcinogenesis by nitrofurazone. Nitrofurazone significantly stimulated the proliferation of estrogen-dependent MCF-7 cells. Nitrofurazone caused Cu(II)-mediated damage to P-32-5'-end-labeled DNA fragments obtained from human genes only when cytochrome P450 reductase was added. DNA damage was inhibited by catalase and bathocuproine. DNA damage was preferably induced at the 5'-ACG-3' sequence, a hotspot of the p53 gene. These findings suggest that nitrofurazone metabolites are involved in tumor initiation through oxidative DNA damage and nitrofurazone itself enhances cell proliferation, leading to promotion and/or progression in carcinogenesis. (C) 2004 Elsevier Ireland Ltd. All rights reserved.