Comparison of extraction-based and elution-based polymerase chain reaction testing, and automated and rapid antigen testing for the diagnosis of severe acute respiratory syndrome coronavirus 2.

We aimed to compare the differences in testing performance of extraction-based polymerase chain reaction (PCR) assays, elution-based direct PCR assay, and rapid antigen detection tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We used nasopharyngeal swab samples of patients with coronavirus disease 2019 (COVID-19). We used the MagNA Pure 24 System (Roche Diagnostics K.

10-Year survey on serum antibody positivity rates and titers for measles and rubella in healthcare workers; an observational study at a Japanese university hospital.

Background: We evaluated the effect of the two-dose vaccination strategy, which has been a widely adopted as childhood routine schedule worldwide to acquire herd immunity, on healthcare workers (HCWs) in Japan.

Methods: Between 2010 and 2019, antibody titers for measles and rubella were measured annually among newly employed HCWs at Osaka University Hospital, Japan, using Enzygnost® assays (Siemens Healthcare Diagnostics Co. Ltd.

Trends in hepatitis C virus-associated mortality rates in Japan, 1998-2017.

Background And Aim: The current prevalence of hepatitis C virus infection and hepatitis C virus-associated mortality in Japan falls short of the World Health Organization goal of viral hepatitis elimination by 2030. We aimed to evaluate the trends in hepatitis C virus-associated mortality in Japan.

Methods: This nationwide observational study used the Japanese Vital Statistics from 1998 to 2017 and included all Japanese hepatitis C virus-associated deaths (84 936) of adults aged ≥ 40 years.

Multiplex Real-Time PCR Assay for Six Major Carbapenemase Genes.

The global dissemination of carbapenemase-producing (CPE) is a major concern in public health. Due to the existence of the diversity of carbapenemases, development of an easily available, cost-effective multiplex detection assay for CPE is required worldwide. Using clinically available and reliable equipment, COBAS z480 (Roche Diagnostics K.

Risk for the occupational infection by cytomegalovirus among health-care workers.

Background: Cytomegalovirus (CMV) are ubiquitously distributed worldwide, causing a wide range of clinical manifestations from congenital infection to a life-threatening disease in immunocompromised individuals. CMV can be transmitted via human-to-human contact through body fluids; however, the risk of CMV infection among healthcare workers (HCWs) has not been fully evaluated.

Aim: This study aimed to assess the risk of CMV infection among HCWs through daily medical practices.

Simultaneous and rapid detection method for measles and rubella using single-tube multiplex real-time quantitative RT-PCR.

Patients with measles or rubella infections manifest acute onset fever accompanying systemic exanthema, which are clinically difficult to be distinguish. Rapid diagnosis and differentiation of such epidemic viral diseases is essential to prevent outbreaks. We developed a single-tube multiplex real-time PCR assay for these indistinguishable viruses.

Reduced Seroprevalence of Hepatitis A Virus Among Japanese Healthcare Workers as a Risk Factor for Occupational Infection.

Background: With the improvement in sanitation and hygiene, the incidence of hepatitis A virus (HAV) infection has declined, and its seroprevalence among Japanese people has been reduced. Universal HAV vaccination is yet to be implemented in Japan, and the healthcare workers (HCWs) are at higher risks of acquiring this infection. We herein report the seroepidemiology of HAV infection among HCWs at Osaka University Hospital.

Genomic reorganization by IS26 in a blaNDM-5-bearing FII plasmid of Klebsiella pneumoniae isolated from a patient in Japan.

An NDM-5-producing Klebsiella pneumoniae ST147 strain was isolated from a Japanese patient who had not travelled abroad in at least 5 years. Whole-genome sequencing revealed a genomic rearrangement in an FII plasmid harbouring blaNDM-5 due to the replicative transposition of IS26. A hypothetical structure was proposed for its ancestral plasmid, and comparative genomic analysis of the plasmid suggested the dissemination of structurally similar plasmids harbouring blaNDM-5 in Asian and Middle Eastern countries.

Vaccination strategy for epidemic viral diseases in healthcare workers: Cut-off for optimal immunization.

Healthcare workers (HCWs) are at an increased risk of being exposed to epidemic viral diseases (EVDs), such as measles, rubella, mumps, and varicella-zoster. Currently, in case of the absence of written records on previous immunizations, the Japanese Society for Infection Prevention and Control guidelines require HCWs to have antibody titers higher than laboratory thresholds, possibly leading to over-immunization. We report our vaccination strategy and the consequent incidences of EVDs at the Osaka University Hospital between 2000 and 2016.

Comparison of the Temperature Influence on the Activity of Currently Available Procalcitonin Reagents.

Background: Procalcitonin (PCT) is a stable biomarker for bacterial infections; however, limited data is available on new trivalent reagents. We evaluated temperature influence on the activity of PCT reagents.

Methods: Using both conventional and trivalent reagents, we measured PCT levels of 30 clinical samples, stored residuum at refrigerator (4°C) and room temperature (24°C), and reexamined it after 24 hours.

Available, Bed-sided, Comprehensive (ABC) score to a diagnosis of Methicillin-resistant Staphylococcus aureus infection: a derivation and validation study.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) infections continue to be a leading problem in health care facilities worldwide.

Methods: This single-center retrospective cohort study consisted of a derivation phase and a validation phase. The derivation phase included all patients admitted to Osaka University Hospital between May 2010 and April 2011.

Durability of immunity by hepatitis B vaccine in Japanese health care workers depends on primary response titers and durations.

Background: Health care workers (HCWs) are frequently exposed to hepatitis B virus (HBV) infection. The efficacy and safety of immunization with the hepatitis B (HB) vaccine are well recognized, but the durability of immunity and need for booster doses in those with secondary vaccine response failure remains controversial.

Methods: This was a retrospective cohort study performed at Osaka University Hospital, Japan.

Evaluation of the highly sensitive chemiluminescent enzyme immunoassay "Lumipulse HBsAg-HQ" for hepatitis B virus screening.

Background: Ongoing efforts in the development of HBsAg detection kits are focused on improving sensitivity and specificity. The purpose of this study was to evaluate an improved, highly sensitive quantitative assay, "Lumipulse HBsAg-HQ", a chemiluminescent enzyme immunoassay designed for a fully automated instrument, the "Lumipulse G1200".

Methods: Serum samples for reproducibility, dilution, correlation, sensitivity, and specificity studies were obtained from patients at the Osaka University Hospital.

Novel and Simple Approach to Estimating the Actual Incidence of Blood and Body Fluid Exposure.

Background: There is no current way to determine the actual blood and body fluid exposure (BBFE) incidence in hospitals. We propose a simple, reliable, and widely available method for the accurate estimation of BBFE.

Methods: Data for BBFE for healthcare workers between 2006 and 2015 at Osaka University Hospital were retrospectively extracted from the electronic records.

[Advanced Testing and Laboratory for HBV, HCV, and HIV Infection].

Most target substances for immunoassay of infectious disease are antigens or antibodies which do not exist in the human body. Therefore, the method to set reference values is different from chemistry or hematology testing. High sensitivity is required for infectious disease testing, particularly for screening.

Performance evaluation of four dominant anti-hepatitis B core antigen (HBcAb) kits in Japan for preventing de novo hepatitis B virus (HBV) infection.

Background: The determination of antibody to hepatitis B core antigen (HBcAb) has become an important means of evaluating the risk factors of de novo hepatitis B virus (HBV) infection before starting intensive immunosuppressive drug therapies. Four dominant HBcAb determination reagents used in Japan were evaluated with HBcIgM, HBsAg, HBsAb, HBeAb, and HBV DNA reagents in order to study their clinical utility.

Methods: Four kinds of HBcAb reagent kits (HBcAb Total and HBcAb-IgG reagent) were evaluated with 526 clinical specimens, including 344 negative specimens, at Osaka University Hospital.

Evaluation of human immunodeficiency virus-1/2 antigen/antibody immunochromatographic assay.

Background: In Japan, an immunochromatographic HIV-1/2 assay has been used for local Health Care Centers to prevent HIV spread in early stages and for hospitals at night or on holidays, where automated instruments are not available. In 2009, a new immunochromatographic HIV-1/2 assay became available which detects both antigen (Ag) and antibody (Ab) simultaneously and on separate bars. This study was conducted to evaluate the clinical performance of this new assay against three HIV-1/2 assays.

[The new method for detecting the outbreak sign of MRSA].

Conventional outbreak detection laboratory-based made one unit from the beginning of the month to the end of the month, totaled and analyzed, cannot correctly detect outbreaks continued during two months. The real-time analysis (RTA) we devised adapts to methicillin-resistant Staphylococcus aureus (MRSA) and avoids the problems of conventional detection. RTA analyzes all data for the last 30 days when MRSA is newly isolated 48 hours or more after hospital admission.

Alterations in hepatitis B virus nucleotide sequences in a chronic virus carrier from immunotolerant to immunoactive phase.

Factors involved in transition from the immunotolerant to immunoactive phase in chronic hepatitis B virus (HBV) infection remain unclear. We investigated viral mutations occurring during transition and elucidated their virological and immunological significance. Full-length HBV DNA sequences were serially determined in a chronic HBV carrier from the immunotolerant to immunoactive phase.

Clinical utility and characteristics of nine anti-HCV antibody screening reagents used in Japan.

Nine anti-HCV antibody screening reagents currently used in Japan were investigated for diagnostic utility. The results using sera from 500 subjects and two series of anti-HCV seroconversion panels were compared. The positive detection rates of the 9 screening tests in 500 specimens ranged from 9.

Mutations associated with the therapeutic efficacy of adefovir dipivoxil added to lamivudine in patients resistant to lamivudine with type B chronic hepatitis.

Factors influencing the therapeutic efficacy of adefovir dipivoxil added to continuing lamivudine have not been elucidated in lamivudine-resistant patients with type B chronic hepatitis. The viral mutations influencing the efficacy of treatment with adefovir dipivoxil were investigated by sequencing analysis of the whole virus genome. Thirty patients resistant to lamivudine receiving adefovir dipivoxil therapy added to lamivudine were studied.

Supportive role played by precore and preS2 genomic changes in the establishment of lamivudine-resistant hepatitis B virus.

Background: Hepatitis B virus (HBV) establishes lamivudine resistance via the resistance-causative rtM204V/I mutation and the replication-compensatory rtL180M mutation. However, both lamivudine-resistant viruses with and those without rtL180M can exist in clinical settings. To elucidate the differences between viruses with and those without rtL180M, we conducted full-length sequencing analysis of HBV derived from patients with type B chronic hepatitis showing lamivudine resistance.

Evaluation of a chemiluminescent microparticle immunoassay for determination of Treponema pallidum antibodies.

Evaluation of a Chemiluminescent Microparticle Immunoassay (CMIA) for determination of anti-Treponema pallidum (TP) antibodies, "ARCHITECT TPAb", was performed. This assay was confirmed to be a reliable anti-TP assay as it showed very good fundamental performance on reproducibility (intra-assay CV: less than 4%), assay specificity (100%, 500/500) and assay sensitivity (100%, 121/121). Since this assay showed very good dilution linearity for samples within the range of 0.