Detecting the performance of methicillin-resistant Staphylococcus aureus by a molecular diagnostic assay in positive blood culture: Influence of coexistence of mecA-positive bacteria and diversity in orfX-SCCmec junction region in methicillin-susceptible S. aureus.

Background: In blood cultures that test positive for staphylococcal bacteria, rapid identification of methicillin-resistant Staphylococcus aureus (MRSA) or methicillin-susceptible Staphylococcus aureus (MSSA) by molecular assay is useful for appropriate antimicrobial treatment of bloodstream infections. Although the Xpert MRSA/SA BC assay is widely available in clinical settings in Japan, its efficacy has not yet evaluated thoroughly.

Methods: We retrospectively studied 100 blood culture cases positive for S.

Is it meaningful to apply midstream urine culture to urine specimens with negative Gram stain results?

Introduction: Gram staining is a convenient method for bacterial estimation. Urine culture is typically used to diagnose urinary tract infections. Therefore, urine culture is also performed on Gram stain-negative urine specimens.

Analysis of diagnostic performance and factors causing nonspecific reactions in SARS-CoV-2 rapid antigen detection tests.

Introduction: Early diagnosis and appropriate infection control are important to prevent the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this study, we aimed to assess the diagnostic performance of SARS-CoV-2 rapid antigen detection (RAD) tests and the factors that cause nonspecific reactions.

Methods: Nasopharyngeal swab specimens (n = 100), sputum specimens (n = 10), and lithium-heparin plasma samples (n = 100) were collected.

Does the timing of saliva collection affect the diagnosis of SARS-CoV-2 infection?

We evaluated the optimal timing of saliva sample collection to diagnose the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We obtained 150 saliva samples at four specific time points from 13 patients with confirmed SARS-CoV-2 infection. The time points were (1) early morning (immediately after waking), (2) immediately after breakfast before tooth brushing, (3) 2 h after breakfast, and (4) before lunch.

Evaluation of false positives in the SARS-CoV-2 quantitative antigen test.

Introduction: Highly sensitive reagents for detecting SARS-CoV-2 antigens have been developed for accurate and rapid diagnosis till date. In this study, we aim to clarify the frequency of false-positive reactions and reveal their details in SARS-CoV-2 quantitative antigen test using an automated laboratory device.

Methods: Nasopharyngeal swab samples (n = 4992) and saliva samples (n = 5430) were collected.

Evaluation of two commercial molecular diagnostic assays: The Xpert Norovirus and the TRCReady NV.

Introduction: Norovirus is highly contagious, and a few particles of this virus are sufficient to make people sick. It is desirable to develop quick and accurate laboratory methods to detect norovirus.

Methods: We evaluated two commercial molecular diagnostic assays, the Xpert Norovirus and the TRCReady NV, using clinical fecal samples.

Clonality investigation of clinical Escherichia coli isolates by polymerase chain reaction-based open-reading frame typing method.

Escherichia coli (E. coli) causes urinary tract infections, pneumonia, surgical site infections, and bloodstream infections and is the important pathogen for both community-acquired and healthcare-associated infections. To investigate the clonality of E.

Inoculum effect of high concentrations of methicillin-susceptible Staphylococcus aureus on the efficacy of cefazolin and other beta-lactams.

The existence of a cefazolin inoculum effect (InE) of methicillin-susceptible Staphylococcus aureus (MSSA), which is speculated to be a reason for cefazolin treatment failure in MSSA infections, is controversial. In Japan, although cefazolin is one of the therapeutic choices for patients with MSSA infection, there are few reports of this effect. Additionally, the association between InE and blaZ type in beta-lactams other than cefazolin has not been well documented.

Diagnostic importance of overexpression of Bmi-1 mRNA in early breast cancers.

Target molecules for a highly sensitive and specific diagnosis of breast cancer in its early clinical stages have not yet been identified. Here, we show the first evidence for diagnostic performance of the molecule B cell-specific Moloney murine leukemia virus integration site 1 (Bmi-1) in breast cancer patients. Only 5 out of 46 non-cancerous samples were positive for Bmi-1 mRNA expression resulting in a sensitivity and specificity of 72.