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Purpose: We investigated the clinical features of Bacteroides bacteremia for 5 years to determine the risk factors for mortality and to ascertain whether bacteremia due to Bacteroides spp. is associated with colorectal carcinoma. Methods: This study comprised a review of all patients with Bacteroides bacteremia at a teaching hospital in Tokyo from April 2003 to March 2008. We also conducted a case-control study between Bacteroides bacteremia and bacteremia due to other pathogens. Results: During the study period, 25 cases of bacteremia were due to Bacteroides spp. Bacteroides bacteremia was associated with a high mortality rate (24%). Malignancy (76%) was the major comorbidity, followed by a history of surgery (40%). Colorectal carcinoma was the most frequent ( n = 8, 32%) of the comorbid malignancies and was recognized as the primary infection site in six cases. Prevalence of colorectal carcinoma as comorbidity was significantly higher in Bacteroides bacteremia than in other bacteremia. Conclusions: In the Bacteroides bacteremia cases of this study, colorectal carcinoma was the major comorbidity and primary infection site. Colorectal carcinoma screening in Bacteroides bacteremia patients is potentially an important diagnostic marker for the early detection of this infection in the future. [ABSTRACT FROM AUTHOR]

Introduction: Since the SARS-CoV-2 Omicron variant became dominant, assessing COVID-19 vaccine effectiveness (VE) against severe disease using hospitalization as an outcome became more challenging due to incidental infections via admission screening and variable admission criteria, resulting in a wide range of estimates. To address this, the World Health Organization (WHO) guidance recommends the use of outcomes that are more specific to severe pneumonia such as oxygen use and mechanical ventilation., Methods: A case-control study was conducted in 24 hospitals in Japan for the Delta-dominant period (August-November 2021; "Delta") and early Omicron (BA.1/BA.2)-dominant period (January-June 2022; "Omicron"). Detailed chart review/interviews were conducted in January-May 2023. VE was measured using various outcomes including disease requiring oxygen therapy, disease requiring invasive mechanical ventilation (IMV), death, outcome restricting to "true" severe COVID-19 (where oxygen requirement is due to COVID-19 rather than another condition(s)), and progression from oxygen use to IMV or death among COVID-19 patients., Results: The analysis included 2125 individuals with respiratory failure (1608 cases [75.7%]; 99.2% of vaccinees received mRNA vaccines). During Delta, 2 doses provided high protection for up to 6 months (oxygen requirement: 95.2% [95% CI:88.7-98.0%] [restricted to "true" severe COVID-19: 95.5% {89.3-98.1%}]; IMV: 99.6% [97.3-99.9%]; fatal: 98.6% [92.3-99.7%]). During Omicron, 3 doses provided high protection for up to 6 months (oxygen requirement: 85.5% [68.8-93.3%] ["true" severe COVID-19: 88.1% {73.6-94.7%}]; IMV: 97.9% [85.9-99.7%]; fatal: 99.6% [95.2-99.97]). There was a trend towards higher VE for more severe and specific outcomes., Conclusion: Multiple outcomes pointed towards high protection of 2 doses during Delta and 3 doses during Omicron. These results demonstrate the importance of using severe and specific outcomes to accurately measure VE against severe COVID-19, as recommended in WHO guidance in settings of intense transmission as seen during Omicron., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Takeshi Arashiro is an unpaid consultant for the World Health Organization. The other authors declare no conflicts of interest., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Among solid organ transplant (SOT) recipients, heart transplant (HT) recipients are at a higher risk of Toxoplasma gondii infection. As Toxoplasma seroprevalence varies by geographic location, updated local epidemiology is essential to guide preventive and therapeutic strategies. However, the Toxoplasma seroprevalence and incidence of post-transplant toxoplasmosis among SOT recipients in Japan are unknown., Methods: We performed a single-center retrospective observational study at an HT center in Tokyo, Japan. All HT recipients aged ≥18 years between 2006 and April 2019 were included. We reviewed patient charts and conducted a questionnaire survey to investigate the risk factors for infection., Results: Among 105 recipients included in the study, 11 (10.5%) were seropositive before transplant. Ninety-five recipients (90.5%), including all pre-transplant seropositive recipients, answered the questionnaire. The recipients who had lived in Okinawa (odds ratio [OR] 7.5 [95% CI 1.42-39.61]; P = .032) and who reported raw-meat eating habits (OR 4.64 [95% CI 1.04-23.3]; P = .021) were more likely to be seropositive. None of the patients developed symptoms of toxoplasmosis. The post-transplant incidence of other major adverse outcomes was not significantly different according to the pre-transplant serostatus., Conclusions: About 10% of HT recipients at an HT center in Tokyo were seropositive for Toxoplasma pre-transplant, and none developed symptomatic toxoplasmosis post-transplant on trimethoprim-sulfamethoxazole. The history of raw meat consumption was associated with seropositivity; therefore, avoiding it might be recommended for HT recipient candidates., Competing Interests: Declaration of Competing Interest All the authors declare no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Invasive meningococcal disease (IMD) can occur in travelers returning from mass-gathering events or endemic regions. We present a 60-year-old Argentine traveler to Tokyo who developed IMD by Neisseria meningitidis Serogroup W135 during her stay in Japan. N. meningitidis serogroup W135 infection has become common in Argentina, whereas IMD less commonly occurs in Japan. Considering the prevalence, the patient most likely acquired the infection in Argentina, and it developed in Japan. Air travel enables passengers to reach the four corners of the world within a few days. IMD should be considered in travelers due to its potential to induce rapid clinical deterioration and transmission., (Copyright © 2022 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

The causative agents of recurrent Escherichia coli bacteremia can be genetically identical or discordant, but the differences between them remain unclear. This study aimed to explore these differences, with regard to their clinical and microbiological features. Patients were recruited from a Japanese tertiary teaching hospital based on blood culture data and the incidence of recurrent E. coli bacteremia. We compared the patients' clinical and microbiological characteristics between the two groups (those with identical or discordant E. coli bacteremia) divided by the result of enterobacterial repetitive intergenic consensus PCR. Among 70 pairs of recurrent E. coli bacteremia strains, 49 pairs (70%) were genetically identical. Patients with genetically identical or discordant E. coli bacteremia were more likely to have renal failure or neoplasms, respectively. The virulence factor (VF) scores of genetically identical E. coli strains were significantly higher than those of genetically discordant strains, with the prevalence of eight VF genes being significantly higher in genetically identical E. coli strains. No significant differences were found between the two groups regarding antimicrobial susceptibility and biofilm formation potential. This study showed that genetically identical E. coli bacteremia strains have more VF genes than genetically discordant strains in recurrent E. coli bacteremia. IMPORTANCE Escherichia coli causes bloodstream infection, although not all strains are pathogenic to humans. In some cases, this infection reoccurs, and several reports have described the clinical characteristics and/or molecular microbiology of recurrent Escherichia coli bacteremia. However, these studies focused on patients with specific characteristics, and they included cases caused by microorganisms other than Escherichia coli. Hence, little is known about the pathogenicity of Escherichia coli isolated from the recurrent one. The significance of our study is in evaluating the largest cohorts to date, as no cohort studies have been conducted on this topic.

Objectives: Biologically false positive (BFP) reactions are well described in early literature. However, only a few recent reports described the incidence and clinical characteristics of patients with BFP reactions. We reviewed the serological test results of patients tested for syphilis in our hospital in the past decade and described the clinical characteristics of patients with BFP reactions., Methods: This is a retrospective study of patients tested for syphilis in a tertiary academic hospital. All serological results were retrieved from the clinical laboratory database. We calculated the incidence of BFP reactions. Clinical characteristics and laboratory data of patients with BFP reactions were reviewed manually., Results: Among 94 462 subjects, 588 patients had BFP reactions (0.62%). Most BFP reactions were observed in patients aged over 60 years, with a history of malignancy and autoimmune diseases. Eighty-five per cent of patients had low rapid plasma reagin (RPR) titre (≤1:4), but two patients had extremely high RPR titre (≥1:256). BFP reactions were more likely to persist beyond 6 months among patients with RPR titre of ≥1:8. There was no statistically significant correlation between RPR titre and total protein albumin gap, surrogate of immunoglobulin levels among patients with BFP reactions., Conclusion: There was a low incidence of BFP reactions in the last decade. A minority of BFP reactions had high non-treponemal antibody titre and persisted longer than 6 months. In the era of re-emergence of syphilis, this information could help clinicians interpret the results of well-established diagnostic tests for syphilis., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Hepatitis E virus (HEV) is a common cause of acute hepatitis. Four major genotypes of HEV have been studied, with genotype 4 being the predominant genotype across Asia. We herein describe the case of a 50-year-old man with a history of human immunodeficiency virus (HIV) infection who was admitted with acute transaminitis. Serum anti-HEV-IgA and HEV-RNA were detected at the time of presentation and further testing revealed HEV genotype 4. To the best of our knowledge, this represents the first clinical case report of acute symptomatic HEV genotype 4 infection in an HIV-positive patient in Japan.

In this study, the performance of the broth microdilution (BMD) method for testing the antimicrobial susceptibility of Clostridium difficile in comparison with the agar dilution (AD) method used by the Clinical and Laboratory Standards Institute (CLSI) was evaluated. In total, 70 non-duplicate C. difficile clinical isolates were used in this study. The minimum inhibitory concentrations (MICs) of clindamycin, moxifloxacin, metronidazole and vancomycin were examined using AD and BMD. The results showed that BMD is acceptable for routine antimicrobial susceptibility testing of C. difficile as its performance was comparable with that of the AD method. In addition, it was noted that metronidazole- and vancomycin-resistant isolates are extremely rare in Japan., (Copyright © 2016 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.)

We examined the molecular characteristics of 13 phenotypically confirmed carbapenemase-positive Enterobacteriaceae clinical isolates, including the relationships between plasmid-mediated quinolone-resistance genes (qnr), 6'-N-aminoglycoside acetyltransferase-encoding genes [aac(6')] and AmpC-encoding genes (pAmpC). Twelve isolates were bla(IMP-1) positive (92.3%), while one was bla(IMP-11) positive (7.7%). We detected qnr, aac(6') and pAmpC genes designated bla(ACT-1)-like in 76.9%, 100% and 53.8%, respectively, of the 13 isolates. Plasmids were transferred successfully for three of the 13 metallo-β-lactamase (MBL)-producing isolates, and the sizes of plasmids extracted from these donors and transconjugants were deduced to be 65 kb or 70 kb. OmpC or OmpF protein expression was reduced in all Enterobacter cloacae, and one Klebsiella oxytoca lacked OmpK36. We demonstrate what appears to be the first evidence that, in Japan, Enterobacteriaceae producing MBLs carry various plasmid-mediated resistance genes, which may cause a further decrease in carbapenem susceptibility through reduction of the expression of outer-membrane proteins.

This study investigated the relationship of plasmid-mediated quinolone resistance (PMQR) and aminoglycoside resistance among oxyimino-cephalosporin-resistant Escherichia coli (n=46) and Klebsiella oxytoca (n=28) clinical isolates in Japan. Seventy-three isolates appeared to produce an extended-spectrum beta-lactamase (ESBL) and one K. oxytoca isolate produced IMP-1 metallo-beta-lactamase (MBL). Polymerase chain reaction (PCR) and sequencing confirmed that eight CTX-M-9/SHV-12-producing isolates, one IMP-1-producing K. oxytoca isolate, and six ESBL-positive E. coli isolates respectively possessed PMQR genes qnrA1, qnrB6, and aac(6')-Ib-cr. All qnr-positive isolates also carried either aac(6')-Ib or aac(6')-IIc aminoglycoside acetyltransferase genes. Resistance determinants to beta-lactams, quinolones and aminoglycosides were co-transferred with a plasmid of ca. 140 kb. The qnrA1 gene was located downstream of insertion sequence ISCR1 in complex class 1 integrons. A novel qnrA1-carrying class 1 integron with the cassette arrangement aac(6')-IIc-aadA2 as well as a unique class 1 integron with bla(IMP-1)-aac(6')-IIc cassettes on the plasmid carrying qnrB6 were found in K. oxytoca isolates. We describe the identification of qnrB6 and aac(6')-Ib-cr and the close association of qnr with aac(6')-Ib and aac(6')-IIc for the first time in clinical isolates producing ESBL or MBL in Japan.

Dengue fever, one of the common endemic viral fevers, often presents with fever, rash, and mild liver dysfunction. However, plasma leakage induced by dengue virus infection can lead to dengue hemorrhagic fever and dengue shock syndrome, and it can cause severe complications including liver failure and encephalopathy. Infection of dengue virus with other pathogens is an unusual but serious complication. We report a case of dengue shock syndrome with liver failure and impaired consciousness. The patient developed a disseminated Candida tropicalis infection, which may have been due to translocation of the fungus from the intestine damaged by the dengue virus.

Clinical characteristics of elderly patients who had been admitted in Sawauchi Hospital for more than 100 days between 1988 and 1992, were analyzed. The average hospital stay of inpatients was 38.0 days, and the longest hospitalization was observed at ages between 76 and 85 year old. During 4 years, there were 74 patients who were admitted for more than 100 days. Thirty-seven cases had serious and complicated conditions, while the remaining 37 cases did not have clear-cut reasons for such a long hospitalization. The latter group was significantly older than the former, and included more females (p < 0.01, respectively; the care-forcussed group). Clinical characteristics of the care-forcussed group were degenerative bone/joint diseases with long-standing pain and uncertain complaints such as autonomic nerve dysfunction. These patients were often admitted to the hospital repeatedly, particularly in winter. Patients with multiple cerebral infarction or chronic respiratory disorders were mostly males (p < 0.01). It is important to examine the clinical course and severity of elderly patients who are in hospital for long periods, particularly from the viewpoint of differentiating quality of treatment and care.