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Gemella is a catalase-negative, facultative anaerobic, Gram-positive coccus that is commensal in humans but can become opportunistic and cause severe infectious diseases, such as infective endocarditis. Few studies have tested the antimicrobial susceptibility of Gemella. We tested its antimicrobial susceptibility to 27 drugs and defined the resistant genes using PCR in 58 Gemella strains, including 52 clinical isolates and six type strains. The type strains and clinical isolates included 22 G. morbillorum, 18 G. haemolysans (GH) group (genetically indistinguishable from G. haemolysans and G. parahaemolysans), 13 G. taiwanensis, three G. sanguinis, and two G. bergeri. No strain was resistant to beta-lactams and vancomycin. In total, 6/22 (27.3%) G. morbillorum strains were erythromycin- and clindamycin-resistant ermB-positive, whereas 4/18 (22.2%) in the GH group, 7/13 (53.8%) G. taiwanensis, and 1/3 (33.3%) of the G. sanguinis strains were erythromycin-non-susceptible mefE- or mefA-positive and clindamycin-susceptible. The MIC90 of minocycline and the ratios of tetM-positive strains varied across the different species—G. morbillorum: 2 µg/mL and 27.3% (6/22); GH group: 8 µg/mL and 27.8% (5/18); G. taiwanensis: 8 µg/mL and 46.2% (6/13), respectively. Levofloxacin resistance was significantly higher in G. taiwanensis (9/13 69.2%) than in G. morbillorum (2/22 9.1%). Levofloxacin resistance was associated with a substitution at serine 83 for leucine, phenylalanine, or tyrosine in GyrA. The mechanisms of resistance to erythromycin and clindamycin differed across Gemella species. In addition, the rate of susceptibility to levofloxacin differed across Gemella sp., and the quinolone resistance mechanism was caused by mutations in GyrA alone.

Geranium dielsianum (GD) is a perennial plant found in the Andean highlands of Peru. Over the decades, the decoction of GD has been consumed as a tea protective against diabetes. Furthermore, GD has traditionally been used as an anti-diabetic, anti-inflammatory, and anti-diarrheal folk medicine. However, there is little scientific evidence elucidating its effects. This study aimed to test the effect of the GD extract on the intestinal environment. In male Sprague–Dawley rats, GD extract increased levels of Bifidobacteria and Lactobacilli and decreased levels of Clostridium leptum subgroup and Bacteroides group in the intestine. Furthermore, 3-hydroxyphenylacetic acid was present at high concentrations in the caecal content of GD extract intake group. Through the above changes in microbiota and microbial metabolites, faecal bulk and moisture increased and caecal pH and putrefactive products decreased. These results suggest that GD extract has a potent prebiotic effect.

Background: We examined the physicochemical properties of IgD-type M protein from 10 patients with IgD-type M protein and those with other types of M protein. Methods: Identification of the L-chain type by routine methods (Immunoelectrophoresis: IEP, Immunofixation electrophoresis; IFE), detection of IgD-IgG complexes and the changes in the mobility by treatment with acid. Results: Identification of the L-chain type by both IEP and IFE was impossible. Only one patient revealed the possibility of IgD-IgG complex bands in 6 of the 10 samples. Changes in mobility by treatment with acid were observed in 8 of the 10 samples of IgD-type M protein. Conclusions: These abnormalities are caused by the primary structure of IgD, which may be related to the wellknown weak reactivity with L-chain antibody. [ABSTRACT FROM AUTHOR]

Background: Nucleic acid amplification testing is the gold standard for SARS-CoV-2 diagnostics, although it may produce a certain number of false positive results. There has not been much published about the characteristics of false positive results. In this study, based on retesting, specimens that initially tested positive for SARS-CoV-2 were classified as true or false positive groups to characterize the distribution of cycle threshold (CT) values for N1 and N2 targets and number of targets detected for each group. Methods: Specimens that were positive for N-gene on retesting and accompanied with S-gene were identified as true positives (true positive based on retesting, rTP), while specimens that retested negative were classified as false positives (false positive based on retesting, rFP). Results: Of the specimens retested, 85/127 (66.9%) were rFP, 16/47 (34.0%) specimens with both N1 and N2 targets initially detected were rFP, and the CT values for each target was higher in rFP than in rTP. ROC curve analysis showed that optimal cutoff values of CT to differentiate between rTP and rFP were 34.8 for N1 and 33.0 for N2. With the optimal cutoff values of CT for each target, out of the 24 specimens that were positive for both N1 and N2 targets and classified as rTP, 23 (95.8%) were correctly identified as true positives. rFP specimens had a single N1 target in 52/61 (85.2%) and a single N2 target in 17/19 (89.5%). Notably, no true positive results were obtained from any specimens with only N2 target detected. Conclusions: These results suggest that retesting should be performed for positive results with a CT value greater than optimal cutoff value for each target or with a single N1 target amplified, considering the possibility of a false positive. This may provide guidance on indications to perform retesting to minimize the number of false positives. [ABSTRACT FROM AUTHOR]

Background: The quantification of hepatitis B virus (HBV) DNA is used to monitor antiviral treatment for HBV infection. Recently, an HBV-DNA quantification reagent and assay protocol have been developed for the μTASWako g1 (Fujifilm Wako Pure Chemical Corporation, Osaka, Japan), a fully automated genetic analyzer that uses PCR-capillary electrophoresis. We evaluated the performance of the newly developed μTASWako HBVDNA assay using standard and clinical samples. Methods: The performance of μTASWako HBV-DNA was evaluated using 3rd World Health Organization International Standard for HBV. Thereafter, we evaluated the correlation between the serum HBV DNA concentrations obtained using the μTASWako HBV-DNA and the Roche Cobas AmpliPrep/COBAS TaqMan HBV test, version 2.0 (CAP/CTM HBV test v.2.0) using 190 serum samples from possible HBV carriers. Results: The limit of detection of the μTASWako HBV-DNA was 7.1 IU/mL and that of the CAP/CTM HBV test v.2.0 was 14.6 IU/mL. Seventy-six of the 190 samples yielded values between 1.3 - 7.8 log IU/mL from both assays. The correlation between the results of the assays for these samples was good, with a Deming regression equation of y = 0.929x + 0.041, 95% confidence intervals (CI) for the slope and intercept of 0.892 - 1.12 and -0.474 - 0.110, respectively, and a correlation coefficient r = 0.924. In the low concentration range of 1.3 - 4.0 log IU/mL (n = 64), the Deming regression equation was y = 0.893x + 0.126, and the 95% CIs for the slope and intercept were 0.915 - 1.342 and -0.930 - 0.025, respectively, and r = 0.809. There was also a close correlation for HBV DNA genotype C (n = 41), with a Deming regression equation of y = 0.975x - 0.048, 95% CIs of the slope and intercept of 0.872 - 1.183 and -0.591 - 0.188, respectively, and r = 0.950. The correlations of the four HBV DNA level categories (not detected, < LLOQ (< 1.3 log IU/mL), 1.3 - 3.2 log IU/mL, and ≥ 3.3 log IU/mL) between the two assays for the 190 samples was also compared, and the overall concordance rate was 81.6% (155/190), with a κ statistic of 0.73 (standard error, 0.040; 95% CI, 0.647 - 0.803). Conclusions: The μTASWako HBV-DNA has a performance comparable with that of the CAP/CTM HBV test, v.2.0. Thus, μTASWako HBV-DNA is useful for the monitoring of HBV infection. [ABSTRACT FROM AUTHOR]

Tests for measuring immunoglobulins include quantitative immunoglobulin assays, serum protein fractionation tests, immunoelectrophoresis, and immunofixation electrophoresis. The presence of abnormal immunoglobulins is suspected when abnormal bands are detected in electrophoresis or when discrepant data appear between tests. Abnormal immunoglobulins include heavy chain disease proteins and half-molecule immunoglobulins that show molecular defects. Such abnormal proteins can be molecularly qualified by SDS-PAGE or immunoblotting. Bence Jones proteins with microheterogenicity can also be demonstrated as the migration changes by immunofixation electro-phoresis of samples before and after enzyme treatment. Furthermore, after agarose membrane electrophoresis, the protein can be spontaneously transferred to a polyvinylidene difluoride (PVDF) membrane for easy immunoblotting. In other words, electrophoresis can be used for both detection and analysis of abnormal immunoglobulins. [ABSTRACT FROM AUTHOR]

Background: The worldwide spread of coronavirus disease 2019 (COVID-19) has led to an urgent need for nucleic acid amplification test (NAAT) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Because NAAT has many manual processes, results may vary depending on the operator. Therefore, it has been required to develop a fully automated testing device and reagent that detects genetic material from SARS-CoV-2. The μTASWako g1 system (FUJIFILM Wako Pure Chemical Corporation, Osaka, Japan), a genetic analyzer, provides results in 75 minutes by performing a fully automated PCR process. Methods: We evaluated the analytical and clinical performance of the μTASWako g1 system for the detection of SARS-CoV-2 RNA. Results: The μTASWako g1 system had the limit of detection at 2,000 copies/mL using a known concentration of RNA. In clinical samples, the μTASWako g1 system had a sensitivity of 88.0% and 100% specificity compared to conventional RT-PCR. The μTAS Wako g1 system could detect three variants of concern carrying spike mutations including N501Y, E484K, and L452R. Conclusions: As the assay on the μTASWako g1 system is highly accurate for the detection of SARS-CoV-2 regardless of the experience of operator, it can be widely applicable in clinical laboratories. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to investigate the immunological and physical characteristics of IgM-λ type M-protein from patients who were measured low in the turbidimetric immunoassay (TIA) IgM assay without error codes for high concentration to determine the cause of the false low levels and to clarify the mechanism of their occurrence. Methods: Materials were IgM patient samples and 8 serum samples from other IgM M-protein patients as controls. Patient samples were assayed by the TIA method, in which five manufacturers and six models (two reagent manufacturers) share the principle, and the BN ProSpec method (nephelometric method), which has a different principle. Dilution linearity tests, IgG addition experiments, isoelectric point electrophoresis, and hydrophobic chromatography were performed on patients and subjects. In addition, the binding capacity of γ-globulin by BIACORE was also examined. Results: The reaction curve of the patient IgM curved downward when the concentration of IgM exceeded 20 g/L, and no error code was obtained. In the measurement by the TIA method of five manufacturers and six models, patient IgM was measured at a false low level with no error code obtained in undiluted dilution by any of the instruments and reagents, but could be measured without any problem by the nephelometric method. In addition, in the patient IgG addition experiment, only patient IgM showed a false low level under high IgG concentration. Furthermore, the binding capacity of patient IgM to γ-globulin (IgG) by BIACORE was significantly higher than that of the control IgM-type M protein. Conclusions: Patient IgM has an affinity (binding capacity) for IgG and forms an IgM-IgG complex under conditions of high IgG concentration. It was speculated that this complex inhibited the reaction with the anti-IgM antibody and the absorbance of the second reaction did not increase, suggesting a false low. [ABSTRACT FROM AUTHOR]

Background: We experienced a patient with multiple myeloma whose urine contained a considerable amount of Bence Jones protein (BJP), which demonstrated poor thermal reactivity in heat coagulation test. The mechanism for this phenomenon was assessed. Methods: Immunoelectrophoretic analyses reveal that a band corresponding to BJP in the urine had 2,600 Dalton by reduction after glycosidase treatment, but not after sialidase treatment. In addition, the glycosidase-treated urine tested positive in heat coagulation test. Conclusions: Glycosylation of the immunoglobulin light chain, which has rarely been seen, is the cause of the unexpected behavior of this patent's BJP in heat coagulation tests. [ABSTRACT FROM AUTHOR]