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.K.) or magLEAD 12gC (Precision System Science Co., Ltd.) for RNA extraction, mixed the concentrates with either the LightMix Modular SARS-CoV PCR mixture (Roche Diagnostics K.K.) or Takara SARS-CoV-2 direct PCR detection kit (Takara Bio Inc.), and amplified it using COBAS® z480 (Roche Diagnostics K.K.). For elution-based PCR, we directly applied clinical samples to the Takara SARS-CoV-2 direct PCR detection kit before the same amplification step. Additionally, we performed Espline SARS-CoV-2 (Fuji Rebio Co., Ltd.) for rapid diagnostic test (RDT), and used Lumipulse SARS-CoV-2 antigen (Fuji Rebio Co., Ltd.) and Elecsys SARS-CoV-2 antigen (Roche Diagnostics K.K.) for automated antigen tests (ATs). Extraction-based and elution-based PCR tests detected the virus up to 214-216 and 210 times dilution, respectively. ATs remained positive up to 24-26 times dilution, while RDT became negative after 22 dilutions. For 153 positive samples, positivity rates of the extraction-based PCR assay were 85.6% to 98.0%, while that of the elution-based PCR assay was 73.2%. Based on the RNA concentration process, extraction-based PCR assays were superior to elution-based direct PCR assays for detecting SARS-CoV-2.

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., Marburg, Germany). The data were categorized by age to compare the antibody positivity rates and antibody titers among no-vaccine, single-dose, and two-dose groups. RESULTS: Over the 10-year period, the annual antibody positivity rates for measles and rubella were 84.0%-95.3% and 90.0%-94.5%, respectively, without any particular trend. The antibody titers for measles (median [interquartile range]: 8.4 [3.9, 20] vs. 6.1 [3.5, 12]) and rubella (11 [5.5, 20] vs. 6 [3.7, 11]) were statistically lower (p < 0.001) in the two-dose generation than in the single-dose generation. DISCUSSION: A shift from single-dose to two-dose vaccination did not yield an increase in antibody positivity rates for both measles and rubella among HCWs. Notably, antibody titers were significantly lower in the two-dose generation. CONCLUSION: Despite several limitations, our data suggests a paradoxical vulnerability in young HCWs who received the two-dose vaccination in a view of sero-positivity rates.

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. METHODS: Serum samples from HCWs at Osaka University Hospital (Japan) were analysed. Initially, we compared CMV IgG seropositivity among HCWs (medical doctors, nurses, and others) in 2017, which was examined after 1 year to evaluate seroconversion rates among those with seronegative results. Then, we examined CMV seroconversion rates in HCWs who were exposed to blood and body fluids. FINDINGS: We analysed 1153 samples of HCWs (386 medical doctors, 468 nurses, and 299 others), of which CMV seropositivity rates were not significantly different (68.9%, 70.3%, and 70.9%, respectively). Of these, 63.9% (221/346) of CMV seronegative HCWs were followed after 1 year, with CMV seroconversion rates of 3.2% (7/221). Among 72 HCWs who tested negative for CMV IgG when exposed to blood and body fluids, the CMV seroconversion rate was 2.8% (2/72). The CMV seroconversion rates between the two situations were not significantly different. CONCLUSION: Our study indicated that CMV infection through daily patient care seems quite rare. Further well-designed studies with a large sample size are warranted to verify our finding.

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. In 2001, we initiated an annual serology check of antibody titers against EVDs and immunization for newly employed HCWs. As an additional vaccination program, all HCWs with low antibody titers were vaccinated in 2005 and 2010. Antibody titers were determined by an enzyme immunoassay (EIA), with a positive range of >2.0 cut-off index. After implementing the vaccination strategy to keep the laboratory threshold, there were only sporadic cases of EVDs among HCWs. More than 99% of individuals who had positive titers in 2005 remained the positive antibody titers in 2010, indicating that a minimum interval of 5 years is enough to measure immunity. Unprotected workers can, even silently, transmit the contagious viruses to patients and coworkers, possibly resulting in a nosocomial outbreak. However, over-vaccination may yield adverse effects and financial burdens. Our observational data indicate that the laboratory cut-off index of >2.0 by EIA may provide a sufficient herd immunity to prevent EVDs among HCWs.

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. We used previously-reported primer settings, with a slight modification of reporter dye, and applied to multiplex Taqman real-time PCR by cobas z480 (Roche Molecular Systems, Inc.). Consequently, the assay could detect 10 copies/10 µl of measles and rubella with coefficient of variations of 11.2% and 21.8%, respectively. Strengths of our methodology include simplicity of operation, short measurement time (2 h), uses of internal control (confirming a run of PCR), and quantitative measurement with high sensitivity. Both measles and rubella currently cause social outbreaks in Japan. We hope that our single-tube multiplex assay contributes to an early diagnosis, leading to an appropriate infection control measure and prevention of epidemics.

A fatal case of Exophiala dermatitidis disseminated infection in an allogenic hematopoietic stem cell transplant recipient during micafungin therapy.

Exophiala dermatitidis is a dematiaceous fungus that is increasingly becoming the cause of fungal infection in immunocompromised patients. However, the risk factors and optimal treatment modality for E. dermatitidis infection are unknown to date. Herein, we present a fatal case of E. dermatitidis infection in an adult patient that developed after allogeneic hematopoietic stem cell transplantation for chronic active Epstein-Barr virus infection. The dematiaceous fungus caused a breakthrough fungemia despite prophylactic administration of micafungin. Although the patient was intensively treated with liposomal-amphotericin B and voriconazole, serum level of beta-D-glucan continuously increased, and the patient eventually died because of cerebral hemorrhage. An autopsy found multiple involvements of the fungal infection at the bilateral lungs, thoracic cavities, diaphragm, and thyroid. To the best of our knowledge, this is the first reported case of E. dermatitidis infection involving these tissues as determined via autopsy. This case highlights the importance of attention for Exophiala infection in immunocompromised individuals in those given antifungal therapy with echinocandins.

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. We proposed a provisional available, bed-sided, comprehensive (ABC) score, and evaluated its accuracy using the clinical diagnosis as a reference. We subsequently revised ABC scores based on k coefficient scores of each variable; this revision was validated by applying it to another patient population. RESULTS: A total of 172 patients and 154 cases were enrolled in the derivation and validation studies, respectively. The revised ABC score consisted of four simple variables: type of clinical specimen (1 to 3 points), Gram-staining result (1 point), presence of local inflammation (2 points), and a systemic inflammatory response (2 points). A revised score of ≥5 points was sensitive (93.8%) and specific (90.6%), and the area under the receiver-operating curve was 0.969 (95% CI; 0.957-1). CONCLUSIONS: We developed a simple and comprehensive scoring system for diagnosis of nosocomial MRSA infections; this system is applicable in a wide variety of situations.

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. METHODS: Between September and October 2017, we collected serum samples submitted to our laboratory for HCWs health examination and tested for the anti-HAV antibody. RESULTS: Overall HAV seropositivity rate was 5.1% (22/436 samples). The seroprevalence was higher among those in the twenties (6.0%) and thirties (8.0%), compared to older age groups. CONCLUSIONS: In this age of internationalization, the decreasing immunity for HAV places HCWs at risk of developing the disease. As a preventive measure against occupational infection, HAV vaccination may be needed for Japanese HCWs.

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. We defined a reduction rate as a percentage of PCT level at 24 hours compared to that after defrost and evaluated a ratio of reduction rate in 4°C to that in 24°C. RESULTS: The reduction rate at room temperature decreased significantly compared to that in the refrigerated condition for all the reagents examined (p < 0.001). In addition, the ratio of reduction rate between the conventional and trivalent reagents showed a significant difference (p < 0.001). CONCLUSIONS: The serum PCT levels significantly decrease at room temperature, particularly when using newer trivalent reagents.

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. Seroconversion and sensitivity panels were purchased from a commercial vender. Subtype, sensitivity panels, and HBsAg recombinant proteins with one or two amino acid substitutions were prepared in-house. RESULTS: The coefficients of variation for the low, medium, and high concentration samples ranged from 1.93 to 2.55%. The HBsAg-HQ reagent for dilution testing showed good linearity in the 0.005-150 HBsAg IU/mL range and no prozone phenomenon. All 102 HBV carrier samples were positive by HBsAg-HQ, while other commercial reagents showed one or more to be negative. In the seroconversion panel, the 14-day blood sample was positive. The sensitivity against HBsAg-HQ "ad" and "ay" subtypes was 0.025 ng/mL. Comparisons among the HBsAg-HQ, HISCL, and Architect HBsAg reagents were performed using the Bland-Altman plot. Specificity for 1000 seronegative individuals was 99.7%. HBsAg-HQ detected 29 positive serum among 12 231 routinely obtained serum samples, which showed concentrations of 0.005-0.05 HBsAg IU/mL. CONCLUSIONS: According to these results, the Lumipulse HBsAg-HQ assay, with a highly sensitive limit of detection of 0.005 IU/mL, may facilitate the development of a better management strategy for a considerable proportion of infected patients.

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. Annual positivity of hepatitis C virus (HCV) antibody in the source individuals and overall patient population were calculated over time. We created an estimation formula focusing on the difference in HCV positivity between the source individuals and overall patient population for the actual number of BBFEs. A linear regression model was used to evaluate the temporal change in the reported and estimated BBFEs. RESULTS: During the study period, 937 BBFEs were reported. HCV positivity between the post-BBFE cohort and overall patient population greatly differed; the incidence ratio ranged from 2.1 to 5.7. The linear regression model revealed that the reported BBFEs did not significantly change during the study period (the slope, 1.315 [95% confidence interval (C.I.): -0.849 to 3.480, p = 0.199]). The annual incidence ratio of the estimated and reported BBFEs significantly reduced over time (the slope, -0.287 [95% C.I.: -0.488 to -0.086, p = 0.011]), indicating that, although the reported number of BBFEs seemed unchanged, the estimated incidence decreased. CONCLUSIONS: We propose a novel and simple approach to estimating the actual incidence of BBFEs in hospitals using the difference in HCV positivity between the post-BBFE cohort and overall patient population.

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. The dynamic range of each kit was evaluated by testing serially diluted serum from pooled sera with high HBcAb concentration. RESULTS: The reagent that showed the largest dynamic range was the Lumipulse HBcAb-N (HBcAb-IgG reagent). Regarding clinical sensitivity and specificity, Centaur HBcAb (HBcAb Total reagent) gave several "doubtful negative" results and ARCHITECT HBcII (HBcAb Total reagent) had the most discrepant positive results. By comparing the cut-off-index distribution of negative specimens using a parameter of "distance from the mean to the cut-off divided by the SD", Centaur was determined to be the best (distance/SD = 12.65), with Lumipulse and Elecsys Anti-HBc (HBcAb Total reagent) in the second group (8.13 and 7.00, respectively), and ARCHITECT rated as the worst (3.25). CONCLUSIONS: In this evaluation, Elecsys and Lumipulse HBcAb kits showed good clinical sensitivity and specificity and were considered to be suitable for evaluating the risk factors of de novo HBV infection.

Correlation between outbreaks of multidrug-resistant Pseudomonas aeruginosa infection and use of bronchoscopes suggested by epidemiological analysis.

An outbreak of Multi-Drug Resistance Pseudomonas aeruginosa (MDRP) infections occurred in intensive care unit (ICU) and emergency room (ER) between June and August 2007. Five patients who isolated MDRP in the outbreak of 2007 were all used bronchoscopes, thus, we suspected contamination of the bronchoscopes as the cause of outbreak. Although we did not detect MDRP from any bronchoscopes, the outbreak finally ended after all the bronchoscopes had been disinfected appropriately with the reexamination of washing process in 2008 and 2009. We retrospectively reviewed eleven patients who isolated MDRP in 2006 and 2007, and the fact was revealed that bronchoscopes were used in most patients in ICU and ER. Bronchoscopes were significantly used during 2006-2007 period, compared with 2008-2009 period in ICU and ER, and the case-control analysis among all Pseudomonas aeruginosa isolated patients identified that bronchoscopes [risk ratio (RR) 8.25, 95% confidence interval (CI) 1.328-51.26] was one of the most important risk factors for MDRP isolation. Duration from admission to MDRP isolation was significant longer in MDRP-isolated cases (19.82±12.77 d), compared with in non MDRP-isolated controls (11.76±11.69 d: p=0.0453). Our epidemiological analysis suggested the significant risk factors for an MDRP outbreak, and could contribute the estimation of the focus and prevention of future outbreaks.

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. METHODS: One immunochromatographic assay (ICA) for HIV Ab detection, one chemiluminescent enzyme immunoassay (CLEIA) for Ab detection and one ELISA for Ag/Ab combination assay were evaluated with the ICA for Ag/Ab detection. Serum samples from 955 patients were used at Osaka University Hospital, who had been tested initially for HIV infection status. The 900 were negative and 55 were positive. In addition, the samples in 10 commercially available panels [2 containing relatively rare HIV subtypes/genotypes and 8 containing seroconversion samples] were tested using all HIV assays. RESULTS: The HIV Ag/Ab ICA showed 100% (900/900, 95% confidence interval (95 CI) 99.59 - 100%) clinical specificity and was better than 99.8% (898/900, 95 CI 99.20 - 99.97%) of the existing ICA. The CLEIA and ELISA showed 100% (600/600, 95 CI 99.39 - 100%) and 99.8% (598/600, 95 CI 98.80 - 99.96%) specificity, respectively. The HIV Ag/Ab ICA showed 100% (55/55, 95 CI 93.51 - 100%) clinical sensitivity and detected all the relatively rare HIV subtypes/genotype panels; these results were the same as the other three assays. The HIV Ag/Ab ICA detected 5 seroconversion panels earlier than antibody-only-detection assays but detected later with 2 panels than ELISA for Ag/Ab combination assay. CONCLUSIONS: The HIV Ag/Ab ICA demonstrated good performances in clinical specificity and sensitivity as a rapid assay and is a suitable assay for qualitative judgement of HIV Ag and Ab simultaneously in human serum and plasma.

Methicillin-resistant Staphylococcus aureus bacteremia at a university hospital in Japan.

Methicillin-resistant Staphylococcus aureus (MRSA) has become a leading cause of infections in hospitals, and mortality from MRSA bacteremia is high. In this study, we assessed the clinical characteristics and optimum management of 115 patients with MRSA bacteremia who were admitted to Osaka University Hospital between January 2006 and December 2010. Sixty-nine of the patients survived and 46 died of heart failure or renal failure. The nonsurvivors had reduced levels of platelets and albumin, and increased aspartate aminotransferase, total bilirubin, blood urea nitrogen, and creatinine levels. Other causes of death included sepsis, septic shock plus respiratory failure, disseminated intravascular coagulation, and unknown causes. However, a significant number of those whose infections were catheter-derived survived. Nonsurvivors were more often administered catecholamines and consultation with an infection-control team (ICT) was significantly associated with improved survival. Patients about whom the ICT were consulted were administered significantly more additional anti-MRSA drugs, for example trimethoprim-sulfamethoxazole, clindamycin, and gentamycin, than patients who were not the subject of consultation, although trough values for vancomycin did not differ between the two groups. Catheter removal was significantly higher for surviving patients with severe or complicated infections. These results suggest the status of patients with MRSA bacteremia who did not survive was worse than those who did survive, but that ICT consultation might significantly affect survival by recommendation of appropriate care and anti-MRSA drug use.

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

The global dissemination of carbapenemase-producing Enterobacteriaceae (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.K., Tokyo, Japan), we developed a multiplex real-time PCR assay for the detection of two combinations of carbapenemases; first, blaNDM, blaKPC, and blaIMP (Set 1), and second, blaGES, blaOXA-48, and blaVIM (Set 2). We constructed standard curves for each carbapenemase gene using serial dilutions of DNA standards, then applied reference or clinical isolates with each carbapenemase gene to this assay. The multiplex assay showed satisfactory accuracy to detect CPE genes, with the correlation coefficients of greater than 0.99 for all genotypes. The assay appropriately differentiated the reference or clinical strains harboring each carbapenemase gene without cross reactivity. Lastly, the assay successfully detected multiple genes without false-positive reactions by applying six clinical isolates carrying both NDM and OXA-48-like carbapenemase genes. Major advantages of our assay include multiplicity, simple operation, robustness, and speed (1 h). We believe that the multiplex assay potentially contributes to early diagnosis of CPE with a diverse genetic background.

[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. In the three years from April 2006 to March 2009, we compared the day and number of MRSA outbreaks newly isolated 48 hours or more after hospital admission in 572 subjects using the conventional method and RTA. We also calculated the RTA infection prevention effect. The number of outbreaks detected conventionally numbered 68 cases and those detected by RTA numbered 106 cases. The number of outbreaks newly detected by RTA numbered 38 cases in three years, averaging 4.3 days earlier than conventional detection using conventional method A an average of 15.7 days earlier than conventionally which totals for every end of the month using conventional method B. The effect of infection prevention in the change of RTA from conventional method A presumably decreases MRSA infection to 14-18 persons and it in the change of RTA from conventional method B decreases MRSA infection to 18-25 persons in one year. These results suggested that outbreak detection by RTA could help prevent MRSA outbreak and decrease MRSA infection frequency.

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 9.6% to 12.2% and the agreements between combinations ranged from 97.0-99.4%. In the 7 two-step assays, which employ recombinant antigen solid phase and anti-human antibody detection, i.e. excluding Quick Chaser and PA, agreement ranged from 97.6-99.4%. No relationship was seen between similarities of the antigen used and agreements between the 7 reagents. For the 72 specimens that showed positive with at least one screening reagent, agreements between the 9 reagents and the confirmatory tests (RIBA III) were compared. In specimens that showed positive with multiple reagents, the positive rate of RIBA III was high, thus the possibility of the existence of the anti-HCV antibody was high. In specimens that showed positive in only a single screening reagent, the RIBA III did not test positive, suggesting that the incidence of false positives may be high. The accuracy of each screening reagent was compared to RIBA III as an accuracy standard. It was found that ARCHITECT was the best in accuracy. The distance from mean to cut-off in the anti-HCV antibody negative specimens reflected the incidence of false positives in each reagent. The anti-HCV antibody seroconversion sensitivities in the initial stage of HCV infection were also compared. The earlier detection was seen with Centaur, ELISA and ARCHITECT. Each anti-HCV antibody screening reagent in use has unique features, and it is suggested that caution be used when diagnosing HCV infection on the basis of the results of a single antibody test.

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.