Serum B-cell maturation antigen could be a simple and accurate biomarker to identify and prognosticate monoclonal gammopathy of undetermined significance and smoldering multiple myeloma.

Not available.

Evaluation of an optimal agar medium for detecting hypervirulent Klebsiella pneumoniae using string test.

The string test is a screening method for detecting hypervirulent (hvKp). Agar media are used for string tests; however, the effect of the type of media on the test results remains unclear. We aimed to determine the optimal agar medium and cutoff value for the string test.

Effectiveness of pulse methylprednisolone in patients with non-human immunodeficiency virus pneumocystis pneumonia: a multicentre, retrospective registry-based cohort study.

Background: A recent database study and meta-analysis reported that adjunctive glucocorticoid therapy reduces mortality in patients with non-human immunodeficiency virus-associated (non-HIV) Pneumocystis jirovecii pneumonia (PCP), having hypoxemia. However, the optimal glucocorticoid dose remains unclear. Our study aimed to evaluate the effectiveness of pulse methylprednisolone compared with mild-to-moderate steroid doses in patients with non-HIV PCP.

Soluble B-cell maturation antigen levels for disease monitoring in oligosecretory and nonsecretory relapsed multiple myeloma.

Soluble B-cell maturation antigen (sBCMA) is elevated on multiple myeloma (MM) cells. We investigated whether sBCMA levels correlated with other myeloma tumor volume indicators and its utility in monitoring oligosecretory/nonsecretory (O-S/Non-S) MM. In 115 patients with newly diagnosed MM, sBCMA was compared with M-protein levels, bone marrow plasma cells (BMPCs), circulating tumor cells (CTCs), and total diffusion volume (tDV; estimated by whole-body diffusion-weighted magnetic resonance imaging) at diagnosis.

Antimicrobial resistance and AmpC production in ESBL-producing Klebsiella pneumoniae and Klebsiella quasipneumoniae: A retrospective study in Japanese clinical isolates.

Introduction: The study of Klebsiella quasipneumoniae, Klebsiella variicola, and AmpC production in extended-spectrum β-lactamase (ESBL)-producing Klebsiella in Japan is limited, and existing data are insufficient. This study aims to characterize Klebsiella species, determine AmpC production rates, and analyze antimicrobial resistance patterns in ESBL-producing Klebsiella isolates in Japan.

Methods: A total of 139 clinical isolates of ESBL-producing Klebsiella were collected in Japan, along with their corresponding antimicrobial susceptibility profiles.

Low-Dose vs Conventional-Dose Trimethoprim-Sulfamethoxazole Treatment for Pneumocystis Pneumonia in Patients Not Infected With HIV: A Multicenter, Retrospective Observational Cohort Study.

Background: Trimethoprim-sulfamethoxazole (TMP-SMX) is an effective treatment for Pneumocystis jirovecii pneumonia (PCP) in immunocompromised patients with and without HIV infection; however, a high incidence of adverse events has been observed. Low-dose TMP-SMX is a potentially effective treatment with fewer adverse events; however, evidence is limited.

Research Question: What is the efficacy and safety of low-dose TMP-SMX for non-HIV PCP compared with conventional-dose TMP-SMX after adjusting for patient background characteristics?

Study Design And Methods: In this multicenter retrospective cohort study, we included patients diagnosed with non-HIV PCP and treated with TMP-SMX between June 2006 and March 2021 at three institutions.

Time to positivity of Corynebacterium in blood culture: Characteristics and diagnostic performance.

The presence of Corynebacterium in blood samples can indicate true bacteremia or contamination, thus complicating the diagnosis of true bacteremia. We aimed to evaluate the usefulness of time to positivity (TTP) in diagnosing true bacteremia and contamination in cases where Corynebacterium was isolated from blood samples. We compared the TTP of the true-bacteremia group (n = 77) with that of the contamination group (n = 88).

Clinical characteristics and antimicrobial susceptibility of , and isolated from human urine in Japan.

The three species , and are difficult to distinguish, owing to their similar biochemical properties, and are often confused in medical practice. There is a scarcity of data comparing the clinical characteristics and antimicrobial susceptibility of , and . We believe that knowledge of the characteristics of each species will help in their better identification.

Genetic and epidemiological analysis of ESBL-producing Klebsiella pneumoniae in three Japanese university hospitals.

Introduction: We aimed to clarify the genetic background and molecular epidemiology of extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae (K. pneumoniae) at three geographically separated university hospitals in Japan.

Methods: From January 2014 to December 2016, 118 ESBL-producing K.

Catheter-related bloodstream Mycobacterium wolinskyi infection in an umbilical cord blood transplant recipient: a case report.

Background: Catheter-related bloodstream infection (CRBSI), caused by rapidly growing mycobacteria (RGM), is a rare infectious complication in hematopoietic stem cell transplant (HSCT) recipients and can often be misdiagnosed as Gram-positive rod (GPR) bacteremia.

Case Presentation: We present a case of CRBSI caused by Mycobacterium wolinskyi, a rare RGM, in a 44-year-old female patient who received an umbilical cord blood transplant.

Conclusions: Rapidly growing mycobacteria can stain as GPRs and may grow in routine blood culture media after 3-4 days of incubation.

Low cut-off value of serum (1,3)-beta-D-glucan for the diagnosis of Pneumocystis pneumonia in non-HIV patients: a retrospective cohort study.

Background: Non-human immunodeficiency virus (HIV) Pneumocystis pneumonia (PCP) is a fulminant disease with an increasing incidence. The serum beta-D-glucan (BDG) assay is used as an adjunct to the diagnosis of PCP; however, the cut-off value for this assay is not well-defined, especially in the non-HIV PCP population. Therefore, we aimed to identify the assay cut-off value for this population.

Potential for false-positive results with quantitative antigen tests for SARS-CoV-2: A case of a child with acute respiratory infection.

The quantitative antigen test based on the chemiluminescent enzyme immunoassay for SARS-CoV-2 has been used in international airports for quarantine in Japan. While cases of false-positive rapid antigen tests for SARS-CoV-2 were reported, false-positive cases of the quantitative antigen test with clinical information are rare. Here, we report a case of acute respiratory infection whose quantitative antigen test for SARS-CoV-2 was suspected to be false positive.

A case of Salmonella osteomyelitis mimicking a malignant tumor of the humerus in an immunocompetent adult patient identified using broad-range polymerase chain reaction with sequencing of a biopsied specimen.

Background: Salmonella infections are associated with gastroenteritis, enteric fever, bacteremia, focal infection, and chronic carrier state. Cases of Salmonella osteomyelitis are uncommon and mainly occur in individuals with immunosuppressive conditions. Herein, we report a case of Salmonella osteomyelitis that required differentiation from malignancy in an immunocompetent adult patient.

Examination of conditions for regular internal quality control in identification of microorganisms using MALDI-TOF MS.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was approved for medical use in 2011, and is currently used as a rapid, accurate and low-cost technique for bacterial identification. Microbiological testing and internal accuracy control in Japan are mainly implemented in accordance with the standards of the Clinical and Laboratory Standards Institute (CLSI). However, few facilities perform internal accuracy control of bacterial identification by MALDI-TOF MS.

Development of an improved rapid BACpro® protocol and a method for direct identification from blood-culture-positive bottles using matrix-assisted laser desorption ionization time-of-flight mass spectrometry.

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been incorporated into pathogenic bacterial identification methods and has improved their rapidity. Various methods have been reported to directly identify bacteria with MALDI-TOF MS by pretreating culture medium in blood culture bottles. Rapid BACpro® (Nittobo Medical Co.

Nationwide surveillance of bacterial respiratory pathogens conducted by the surveillance committee of Japanese Society of Chemotherapy, the Japanese Association for Infectious Diseases, and the Japanese Society for Clinical Microbiology in 2010: General view of the pathogens' antibacterial susceptibility.

The nationwide surveillance on antimicrobial susceptibility of bacterial respiratory pathogens from patients in Japan, was conducted by Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases and Japanese Society for Clinical Microbiology in 2010. The isolates were collected from clinical specimens obtained from well-diagnosed adult patients with respiratory tract infections during the period from January and April 2010 by three societies. Antimicrobial susceptibility testing was conducted at the central reference laboratory according to the method recommended by Clinical and Laboratory Standard Institutes using maximum 45 antibacterial agents.

[Performance of two matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) models for identification of bacteria isolated from blood culture].

We compared the results of two bacterial identification methods: 1) a traditional method based on phenotypic identification of the causative organism using gram-staining, culture and biochemical markers and 2) matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). A total of 111 isolates, including 107 strains of common bacteria species and 4 strains of 3 yeast species, were tested by the traditional method and MALDI-TOF MS method(VITEK MS and Micro flex LT). Data obtained using MALDI-TOF MS were classified as Level 1 and Level 2 according to the confidence level of identification results from the VITEK MS ver.