Multidrug-Resistant and Carbapenemase Gene-Carrying Acinetobacter colistiniresistens Isolated from Bloodstream Infection.

In this study, we investigated the antimicrobial susceptibility and molecular characteristics of antimicrobial resistance of Acinetobacter colistiniresistens strains isolated from the bloodstream using whole-genome sequencing. Clinical isolates identified as Acinetobacter baumannii and showing colistin resistance at the time of detection were collected. Antimicrobial susceptibility was determined using the VITEK2 system (bioMérieux) and Sensititre system (Thermo Fisher Scientific). Species identification and antimicrobial resistance gene searches were performed through whole-genome sequencing. Through whole-genome sequencing, three colistin-resistant strains from the bloodstream were identified as A. colistiniresistens. All three A. colistiniresistens strains were resistant to two or more antimicrobial agents except for colistin, and two of them were resistant to carbapenems. Genes involved in aminoglycoside [AAC(3)-Ⅱb, AAC(6')-Ⅰj, aadA2, ANT(3″)-Ⅱb, APH(3')-Ⅵa], macrolide (mphD, msrE), carbapenem and cephalosporin (OXA-420, VIM-2), fluoroquinolone and tetracycline (adeF), and sulfonamide (sul1, sul2) resistance were detected. We report multidrug-resistant A. colistiniresistens strains isolated from the bloodstream through whole-genome sequencing. Two strains carried carbapenemase genes, and this is the first report of VIM-2-producing A. colistiniresistens.

The Impact of the Rapid Blood Culture Identification Panel on Antibiotic Treatment and Clinical Outcomes in Bloodstream Infections, Particularly Those Associated with Multidrug-Resistant Micro-Organisms.

We evaluated the impact of the FilmArray blood culture identification (BCID) panel on the time taken to administer effective antibiotics and the clinical outcomes of bloodstream infections. We retrospectively screened patients with bloodstream infections who underwent BCID testing and compared them to a historical control group that received conventional culture testing. A total of 144 and 214 patients who underwent BCID and conventional cultures, respectively, were compared. The 30-day mortality (BCID: 9.7% vs. conventional method: 10.7%, p = 0.755), time to effective antibiotic administration (3 h for both BCID and conventional method, p = 0.789), and time to appropriate antibiotic administration did not differ significantly between the groups. BCID was not significantly associated with 30-day mortality after adjusting for the Pitt bacteremia score and the Charlson comorbidity index (adjusted OR = 0.833, CI; 0.398-1.743). Compared with conventional methods, BCID reduced the time to administration of effective antibiotics in cases of carbapenem-resistant Enterobacterales (CRE) (39 h vs. 93 h, p = 0.012) and vancomycin-resistant enterococci (VRE) (50 h vs. 92 h, p < 0.001) bacteremia. BCID did not affect the clinical outcomes of overall bloodstream infections; however, it contributed to the early administration of effective antibiotics in cases of CRE and VRE bacteremia.

Association between Pneumonia Development and Virulence Gene Expression in Carbapenem-Resistant Acinetobacter baumannii Isolated from Clinical Specimens.

We investigated the virulence gene expression of carbapenem-resistant Acinetobacter baumanii (CRAB) isolated from the respiratory samples of patients with CRAB pneumonia and those with CRAB colonization to identify the virulence genes contributing to CRAB pneumonia's development and mortality. Patients with CRAB identified from respiratory specimens were screened at a tertiary university hospital between January 2018 and January 2019. Patients were classified into CRAB pneumonia or CRAB colonization groups according to predefined clinical criteria. A. baumannii isolated from respiratory specimens was examined for the expression levels of ompA, uspA, hfq, hisF, feoA, and bfnL by quantitative reverse-transcription polymerase chain reaction. Among 156 patients with CRAB from respiratory specimens, 17 and 24 met the criteria for inclusion in the pneumonia and colonization groups, respectively. The expression level of ompA was significantly higher in the pneumonia group than in the colonization group (1.45 vs. 0.63, P=0.03). The expression levels of ompA (1.97 vs. 0.86, P=0.02), hisF (1.06 vs. 0.10, P < 0.01), uspA (1.62 vs. 1.01, P < 0.01), and bfnL (3.14 vs. 2.14, P=0.03) were significantly higher in patients with 30-day mortality than in the surviving patients. Elevated expression of hisF (adjusted odds ratio = 5.93, P=0.03) and uspA (adjusted odds ratio = 7.36, P=0.02) were associated with 30-day mortality after adjusting for age and the Charlson score. uspA and hisF may serve as putative targets for novel therapeutic strategies.

Multicenter performance evaluation of the Alinity m CMV assay for quantifying cytomegalovirus DNA in plasma samples.

Monitoring of cytomegalovirus (CMV) viral load is critical for informing treatment decisions in order to prevent the severe health consequences of CMV infection or reactivation of latent CMV in immunocompromised individuals. This first field evaluation examined the analytical and clinical performance of the Alinity m CMV assay. Analytical performance was assessed with a commercially available six-member panel, while the clinical performance evaluation compared the Alinity m CMV assay to the RealTime CMV assay and a laboratory-developed test (LDT) as the test of record at three large hospital-based clinical laboratories. Precision of the Alinity m CMV assay was demonstrated with total standard deviation (SD) between 0.08 and 0.28 Log IU/mL. A total of 457 plasma specimens were tested on the Alinity m CMV assay and compared to the test of record at each site (n = 304 with RealTime CMV and n = 153 with LDT CMV). The Alinity m CMV assay had excellent correlation (correlation coefficient r ≥0.942) in comparison to the RealTime CMV or LDT CMV assays. The mean observed bias ranged from -0.03 to 0.34 Log IU/mL. Median onboard turnaround time of Alinity m CMV was less than 3 h. When the CMV assay is run on the Alinity m system, it has the capacity to shorten time to result and, therefore, to therapy.

Tonic Activation of NR2D-Containing NMDARs Exacerbates Dopaminergic Neuronal Loss in MPTP-Injected Parkinsonian Mice.

NR2D subunit-containing NMDA receptors (NMDARs) gradually disappear during brain maturation but can be recruited by pathophysiological stimuli in the adult brain. Here, we report that 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intoxication recruited NR2D subunit-containing NMDARs that generated an Mg2+-resistant tonic NMDA current (INMDA) in dopaminergic (DA) neurons in the midbrain of mature male mice. MPTP selectively generated an Mg2+-resistant tonic INMDA in DA neurons in the substantia nigra pars compacta (SNpc) and ventral tegmental area (VTA). Consistently, MPTP increased NR2D but not NR2B expression in the midbrain regions. Pharmacological or genetic NR2D interventions abolished the generation of Mg2+-resistant tonic INMDA in SNpc DA neurons, and thus attenuated subsequent DA neuronal loss and gait deficits in MPTP-treated mice. These results show that extrasynaptic NR2D recruitment generates Mg2+-resistant tonic INMDA and exacerbates DA neuronal loss, thus contributing to MPTP-induced Parkinsonism. The state-dependent NR2D recruitment could be a novel therapeutic target for mitigating cell type-specific neuronal death in neurodegenerative diseases.SIGNIFICANCE STATEMENT NR2D subunit-containing NMDA receptors (NMDARs) are widely expressed in the brain during late embryonic and early postnatal development, and then downregulated during brain maturation and preserved at low levels in a few regions of the adult brain. Certain stimuli can recruit NR2D subunits to generate tonic persistent NMDAR currents in nondepolarized neurons in the mature brain. Our results show that MPTP intoxication recruits NR2D subunits in midbrain dopaminergic (DA) neurons, which leads to tonic NMDAR current-promoting dopaminergic neuronal death and consequent abnormal gait behavior in the MPTP mouse model of Parkinson's disease (PD). This is the first study to indicate that extrasynaptic NR2D recruitment could be a target for preventing neuronal death in neurodegenerative diseases.

Analgesic efficacy of median nerve stimulation in mice with chemotherapy-induced peripheral neuropathymodulation of brain-derived neurotrophic factor expression.

OBJECTIVE: Chemotherapeutic agents such as docetaxel (DTX) can trigger chemotherapy-induced peripheral neuropathy (CIPN), which is characterized by unbearable pain. This study was designed to investigate the analgesic effect and related neuronal mechanism of low-frequency median nerve stimulation (LFMNS) on DTX-induced tactile hypersensitivity in mice. METHODS: To produce CIPN, DTX was administered intraperitoneally 4 times, once every 2 d, to male ICR mice. LFMNS was performed on the wrist area, and the pain response was measured using von Frey filaments on both hind paws. Western blot and immunofluorescence staining were performed using dorsal root ganglion and spinal cord samples to measure the expression of brain-derived neurotrophic factor (BDNF). RESULTS: Repeated LFMNS significantly attenuated the DTX-induced abnormal sensory response and suppressed the enhanced expression of BDNF in the DRG neurons and spinal dorsal area. CONCLUSIONS: LFMNS might be an effective non-pharmaceutical option for treating patients suffering from CIPN regulating the expression of peripheral and central BDNF.

Inhibition of angiotensin converting enzyme increases PKCßI isoform expression via activation of substance P and bradykinin receptors in cultured astrocytes of mice.

BACKGROUND: Angiotensin-converting enzyme inhibitor (ACEi) inhibits the catalysis of angiotensin I to angiotensin II and the degradation of substance P (SP) and bradykinin (BK). While the possible relationship between ACEi and SP in nociceptive mice was recently suggested, the effect of ACEi on signal transduction in astrocytes remains unclear. OBJECTIVES: This study examined whether ACE inhibition with captopril or enalapril modulates the levels of SP and BK in primary cultured astrocytes and whether this change modulates PKC isoforms (PKCα, PKCßI, and PKCε) expression in cultured astrocytes. METHODS: Immunocytochemistry and Western blot analysis were performed to examine the changes in the levels of SP and BK and the expression of the PKC isoforms in primary cultured astrocytes, respectively. RESULTS: The treatment of captopril or enalapril increased the immunoreactivity of SP and BK significantly in glial fibrillary acidic protein-positive cultured astrocytes. These increases were suppressed by a pretreatment with an angiotensin-converting enzyme. In addition, treatment with captopril increased the expression of the PKCßI isoform in cultured astrocytes, while there were no changes in the expression of the PKCα and PKCε isoforms after the captopril treatment. The captopril-induced increased expression of the PKCßI isoform was inhibited by a pretreatment with the neurokinin-1 receptor antagonist, L-733,060, the BK B1 receptor antagonist, R 715, or the BK B2 receptor antagonist, HOE 140. CONCLUSIONS: These results suggest that ACE inhibition with captopril or enalapril increases the levels of SP and BK in cultured astrocytes and that the activation of SP and BK receptors mediates the captopril-induced increase in the expression of the PKCßI isoform.

Large-Scale Clinical Evaluation of Rapid Blood Culture Identification Panels for Bloodstream Infections at a Tertiary Hospital.

The prompt implementation of optimal antibacterial therapy through the rapid identification of the causative organisms is essential for improving outcomes for critically ill patients with bloodstream infections. We evaluated the clinical performance of the FilmArray blood culture identification (BCID) panel for rapidly identifying causative pathogens in the bloodstream using large-scale clinical samples. We analyzed the results of identification using a BCID panel performed on 2005 positive blood culture bottles from September 2019 to June 2022. Pathogen detection efficiency and interval from Gram staining to identification using the BCID panel were compared to those of conventional identification systems-VITEK MS MALDI-TOF Mass Spectrometer and Vitek2-and antibiotic susceptibility testing-Vitek2. We detected 2167 isolates from 2005 positive blood culture bottles. In these isolates, the BCID panel showed 93% full agreement-both organisms and antimicrobial resistance genes were matched, and no off-target organisms were detected. Species-level discordance was found in 0.6% of tests. Sixty-five isolates (3.0%) were only detected by BCID, whereas 22 isolates (1.0%) from the on-target panel were not detected by BCID. This large-scale study demonstrated that the BCID panel was a reliable and rapid identification method for directly identifying bloodstream pathogens in a positive blood culture.

How Significant Are Xpert Xpress SARS-CoV-2 Test Findings When Only an N2 Gene Is Detected?

The rapid identification of patients infected with COVID-19 during the SARS-CoV-2 pandemic is critical to operating emergency rooms effectively. Xpert Xpress SARS-CoV-2 (Xpert) assays are increasingly being used in the rapid screening of COVID-19. We evaluated the clinical performance of Xpert by comparing findings with those of qRT-PCR evaluations and included the clinical features of patients visiting the emergency department. Positive results with Xpert testing (n = 370) were compared with qRT-PCR findings, demonstrating a 91.9% intertest agreement. We reviewed the subsequent COVID-19 test results and SARS-CoV-2 infection histories for individuals showing discrepancies in Xpert and qRT-PCR testing and determined whether the findings were true-positive or false-positive. The true-positive rate for Xpert testing was 95.4% (353/370); the remaining 17 samples (4.6%) were false-positive. All false-positive data for Xpert testing showed N2 signals amplified to Ct values of ≥40 with no E gene signals. Rapid Xpert testing is highly sensitive and shows a good performance overall in challenging situations, such as an emergency room. However, we considered the possibility of false-positive Xpert results given an N2 gene signal only, especially given high Ct values. We recommend interpreting test data with caution and considering retesting over time.

Development of Machine-Learning Model to Predict COVID-19 Mortality: Application of Ensemble Model and Regarding Feature Impacts.

This study was designed to develop machine-learning models to predict COVID-19 mortality and identify its key features based on clinical characteristics and laboratory tests. For this, deep-learning (DL) and machine-learning (ML) models were developed using receiver operating characteristic (ROC) area under the curve (AUC) and F1 score optimization of 87 parameters. Of the two, the DL model exhibited better performance (AUC 0.8721, accuracy 0.84, and F1 score 0.76). However, we also blended DL with ML, and the ensemble model performed the best (AUC 0.8811, accuracy 0.85, and F1 score 0.77). The DL model is generally unable to extract feature importance; however, we succeeded by using the Shapley Additive exPlanations method for each model. This study demonstrated both the applicability of DL and ML models for classifying COVID-19 mortality using hospital-structured data and that the ensemble model had the best predictive ability.

Performance Evaluation of the VITEK2 and Sensititre Systems to Determine Colistin Resistance and MIC for Acinetobacter baumannii.

Performances of the colistin antimicrobial susceptibility testing (AST) systems of Acinetobacter baumannii vary depending on the manufacturer, and data on colistin-resistant A. baumannii are limited. We evaluated the VITEK2 and Sensititre systems to determine colistin resistance and minimum inhibitory concentration (MIC) for A. baumannii isolated from a clinical microbiology laboratory. A total of 213 clinical A. baumannii isolates were tested, including 81 colistin-resistant A. baumannii. ASTs were performed using the VITEK2 and Sensititre systems according to the manufacturer's instructions. Reference MICs for colistin were determined using the manual broth microdilution method (BMD). The results of the two AST methods were compared with the BMD results. VITEK2 and Sensititre systems showed category agreements of 95.3% and 99.1%, respectively. VITEK2 had a relatively high very major error (VME) rate (9.9%). Sensititre reported higher MICs than the reference method for the susceptible isolates and showed low essential agreement. In conclusion, the automated systems investigated in this study showed good category agreements for colistin AST of A. baumannii. However, VITEK2 had a high VME rate, and Sensititre had differences in MIC results. Colistin AST remains a challenging task in the clinical laboratory.

Analytical Performance Evaluation of Goldstream Fungus (1-3)-ß-D Glucan.

BACKGROUND: (1-3)-ß-D-glucan (BDG) is a fast and simple assay to diagnose invasive fungal infection. In this study, we evaluated the performance of the Goldstream BDG assay (Beijing Gold Mountainriver Tech Development) performed on the automated analyzer, IGL-200 (Genobio Pharmaceutical). METHODS: The precision and linearity of the Goldstream BDG assay were evaluated according to Clinical and Laboratory Standards Institute procedures. BDG results performed on the IGL-200 were compared to a manual photometer, MB-80A (Genobio Pharmaceutical). The manufacturer-provided reference interval was verified. RESULTS: Within-laboratory imprecision (% Coefficient of Variation) was 9.4%. The best polynomial fit was third-order within the manufacturer's claimed linear range (32.0 - 830.0 pg/mL). The BDG assay performed on IGL-200 and MB-80A showed a total agreement of 97.6%. All healthy subjects were within range of the manufacture provided reference interval. CONCLUSIONS: The analytical performance of the Goldstream BDG assay was clinically acceptable.

Different Antimicrobial Susceptibility Testing Methods to Determine Vancomycin Susceptibility and MIC for Staphylococcus aureus with Reduced Vancomycin Susceptibility.

The methods and results obtained using commercialized automation systems used for antimicrobial susceptibility testing are not entirely consistent. Therefore, we evaluated different antimicrobial susceptibility testing methods to determine vancomycin susceptibility and minimum inhibitory concentration (MIC) for Staphylococcus aureus with reduced vancomycin susceptibility (SA-RVS). A total of 128 clinical isolates of S. aureus were tested, including 99 isolates showing an MIC of ≥2 µg/mL using the VITEK2 system (VITEK2). Antimicrobial susceptibility tests were performed using the Sensititre system (Sensititre), Phoenix M50 system (Phoenix), and MicroScan WalkAway 96 Plus system (MicroScan). Vancomycin MICs were determined using the broth microdilution method (BMD) and Etest. Essential agreement and category agreement for each method were compared with BMD results as the reference method. The BMD and Etest showed complete essential agreement (100%). VITEK2, Sensititre, and Phoenix showed high essential agreement (>99%), while MicroScan showed the lowest essential agreement (92.2%). The MIC MICs determined via Etest, VITEK2, and MicroScan tended to be higher than that determined via BMD. When comparing BMD with Etest, the category agreement was 93.8% and minor errors were observed for eight isolates. VITEK2, Sensititre, and Phoenix showed category agreements of 96.1%, 96.1%, and 99.2%, respectively, while MicroScan showed the lowest category agreement of 85.2%. The determination of vancomycin susceptibility and MIC for S. aureus varied among the methods. Caution should be taken when interpreting RVS and intermediate results for S. aureus. For confirmation of SA-RVS results, it would be appropriate to test with BMD or a more reliable testing method.

Whole-genome sequencing for the characterization of resistance mechanisms and epidemiology of colistin-resistant Acinetobacter baumannii.

BACKGROUND: Multidrug-resistant Acinetobacter baumannii is an important causal pathogen of healthcare-associated infections, and colistin-resistant strains have recently emerged owing to the increased use of colistin. Using next-generation sequencing (NGS), a single whole-genome sequencing (WGS) protocol can identify and type pathogens, analyze genetic relationships among different pathogens, predict pathogenic transmissions, and detect antibiotic resistance genes. However, only a few studies have applied NGS in studying the resistance mechanism and epidemiology of colistin-resistant A. baumannii. This study aimed to elucidate the resistance mechanism of colistin-resistant A. baumannii and analyze its molecular epidemiology through WGS. MATERIALS AND METHODS: The subjects in this study were patients who visited a university hospital between 2014 and 2018. Thirty colistin-resistant strains with high minimum inhibitory concentrations were selected from various patient samples, and WGS was performed. Comparative genomic analysis was performed for the 27 colistin-resistant A. baumannii strains using a colistin-susceptible strain as the reference genome. RESULTS: The WGS analysis found no mutation for lpxA, lpxC, lpx D, pmrA, pmrB, and mcr1, the genes known to be associated with colistin resistance. Fifty-seven coding sequences (CDS) showed differences; they included 13 CDS with known names and functions that contained 21 genes. From the whole-genome multi-locus sequence typing (wgMLST) and single nucleotide polymorphism (SNP) analyses, two major clusters were found for the colistin-resistant A. baumannii strains. However, no differences were observed by the time of detection for each cluster, the samples, the pattern of antibiotic resistance, or the patient characteristics. In the conventional MLST following the Oxford scheme, the typing result showed ST1809, ST451, ST191, ST1837, and ST369 in the global clone 2 (GC2), without any relation with the results of wgMLST and SNP analyses. CONCLUSION: Based on the findings of the resistance gene analysis through WGS and comparative genomic analysis, the potential genes associated with colistin-resistance or CDS were examined. Furthermore, the analysis of molecular epidemiology through WGS regarding colistin-resistant A. baumannii may prove helpful in preventing infection by multidrug-resistant bacteria and controlling healthcare-associated infections.

Serotype Distribution and Antimicrobial Resistance of Salmonella Isolates in Korea between 2016 and 2017.

Salmonella is one of the major causes of food-borne infections. We investigated the serotype distribution and antimicrobial resistance of Salmonella isolates collected in Korea between January 2016 and December 2017. In total, 669 Salmonella isolates were collected from clinical specimens at 19 university hospitals. Serotyping was performed according to the Kauffmann-White scheme, and antimicrobial susceptibility was tested using Sensititre EUVSEC plates or disk diffusion. Among the strains, C (39.8%) and B (36.6%) were the most prevalent serogroups. In total, 51 serotypes were identified, and common serotypes were S. enterica serovar I 4,[5],12:i:- (16.7%), S. Enteritidis (16.1%), S. Bareilly (14.6%), S. Typhimurium (9.9%), and S. Infantis (6.9%). The resistance rates to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole were 32.6%, 12.1%, and 8.4%, respectively. The resistance rates to cefotaxime and ciprofloxacin were 8.1% and 3.0%, respectively, while 5.4% were multidrug-resistant. S. enterica serovar I 4,[5],12:i:- and S. Enteritidis were highly prevalent, and there was an increase in rare serotypes. Multidrug resistance and ciprofloxacin resistance were highly prevalent. Periodic investigations of Salmonella serotypes and antimicrobial resistance are needed.

Comprehensive DNA repair gene expression analysis and its prognostic significance in acute myeloid leukemia.

BACKGROUND: Deficiency in DNA damage response (DDR) pathway and accumulation of DNA damage increases mutation rates resulting in genomic instability and eventually increases the risk of cancer. The aim of our study was to investigate expressions of DNA repair genes as new prognostic biomarkers in acute myeloid leukemia (AML). METHODS: We utilized The Cancer Genome Atlas AML project (TCGA-LAML cohort, 15 acute promyelocytic leukemia (APL) and 155 non-APL AML) for the expression data of DNA repair genes. For validation, clinical samples (Ewha study group, 9 APL and 72 non-APL AML patients) were analyzed for the expression of 22 DNA repair genes using a custom RT2 Profiler PCR Array. RESULTS: APL patients presented significantly lower expression of DNA repair genes than non-APL AML patients in both study groups. Among non-APL AML patients, high expression levels of PARP1, XRCC1, and RAD51 were associated with poor overall survival (OS) probability in both study groups. Furthermore, Cox regression analysis showed that increased expression levels of PARP1, XRCC1, RAD51, BRCA1 and MRE11A could be independent risk factors for OS in the Ewha study group. Among non-APL patients of the Ewha study group, the OS probability of DDR-overexpressed group with at least one gene or more showing Z score greater than 1.5 was poorer than that of DDR non-overexpressed group. CONCLUSION: In the current study, the DNA repair gene expression profile of APL patients was different from that of non-APL AML patients. Overexpression of DNA repair genes could be a poor prognostic biomarker in non-APL AML.

Burn Injury-Induced Pain and Depression-Like Behavior in Mice.

Scalding water is the most common cause of burn injury in both elderly and young populations. It is one of the major clinical challenges because of the high mortality and sequelae in low- and middle-income countries. Burns frequently induce intense spontaneous pain and persistent allodynia as well as life-threatening problem. More importantly, excessive pain is often accompanied by depression, which may significantly decrease the quality of life. This article shows how to develop an animal model for the study of burn-induced pain and depression-like behavior. After anesthesia, burn injury was induced by dipping one hind paw of the mouse into hot water (65 °C ± 0.5 °C) for 3 s. The von Frey test and automated gait analysis were performed every 2 days after burn injury. In addition, depression-like behavior was examined using the forced swimming test, and the rota-rod test was performed to differentiate the abnormal motor function after burn injury. The main purpose of this study is to describe the development of an animal model for the study of burn injury-induced pain and depression-like behavior in mice.

Variant Prediction by Analyzing RdRp/S Gene Double or Low Amplification Pattern in Allplex SARS-CoV-2 Assay.

The spread of delta variants (B.1.671.2) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a severe global threat. Multiplex real-time PCR is a common method for confirming SARS-CoV-2 infection, however, additional tests, such as whole genomic sequencing, are required to reveal the presence or type of viral mutation. Moreover, applying whole genomic sequencing to all SARS-CoV-2 positive samples is challenging due to time and cost constraints. Here, we report that the double or low amplification curve observed during RNA-dependent RNA polymerase (RdRp) gene/S gene amplification in the Allplex SARS-CoV-2 Assay is related to delta/alpha variants. We analyzed the RdRp/S gene amplification curve using 94 samples confirmed as SARS-CoV-2 infection by the Allplex SARS-CoV-2 Assay from January to August, 2021. These positive samples identified variant types using the Novaplex SARS-CoV-2 Variants I and IV Assays. Overall, 17 samples showing a double curve and 11 samples showing a low amplification pattern were associated with alpha-/delta-type strains with variants in the P681 region. The double or low curve shown in the RdRp gene amplification curve had 100% sensitivity and 100% specificity for diagnosing delta/alpha variants. During the SARS-CoV-2 virus diagnostic RT-PCR test using the Allplex SARS-CoV-2 Assay, we could consider the presence of delta/alpha variants in the samples with double or low amplification curve of the RdRp/S gene channel. This PCR amplification curve abnormality enables rapid and cost-effective variant type prediction during SARS-CoV-2 diagnostic testing in clinical laboratories.

Risk of Absence of Measles Antibody in Healthcare Personnel and Efficacy of Booster Vaccination.

We aimed to identify the presence of the measles IgG antibody (mIgG-Ab) in healthcare personnel and finding out who needs the measles vaccination. The history of measles vaccination was obtained from the national vaccine registry. A baseline mIgG-Ab test was performed, and the measles vaccine was administered to participants who tested negative or equivocal for mIgG-Abs. During the study, 2885 (87.3%) of the 3303 employees were tested for measles serostatus. The baseline seropositivity rate for mIgG-Abs was 91.9%. Among the 234 seronegative cases, 82.9% were born after 1985. The seroprevalence rate was lower in those who received the measles-mumps-rubella (MMR) vaccine >10 years before the testing time, especially if they were born after 1985 and if there was only one previous record of vaccination. Among the 234 seronegative cases, MMR vaccination was administered in 174 cases, of which serostatus was evaluated in 146 cases. After the first dose, positive seroconversion was achieved in 126 participants (86.3%). After a second dose, 15 achieved (75.0%) positive seroconversion. In healthcare personnel born after the period when measles incidence significantly decreased, it may be necessary to reassess their immune status for measles if more than 10 years have elapsed since the last vaccination.

Role of DegQ in differential stability of flagellin subunits in Vibrio vulnificus.

Biofilm formation of Vibrio vulnificus is initiated by adherence of flagellated cells to surfaces, and then flagellum-driven motility is not necessary during biofilm maturation. Once matured biofilms are constructed, cells become flagellated and swim to disperse from biofilms. As a consequence, timely regulations of the flagellar components' expression are crucial to complete a biofilm life-cycle. In this study, we demonstrated that flagellins' production is regulated in a biofilm stage-specific manner, via activities of a protease DegQ and a chaperone FlaJ. Among four flagellin subunits for V. vulnificus filament, FlaC had the highest affinities to hook-associated proteins, and is critical for maturating flagellum, showed the least susceptibility to DegQ due to the presence of methionine residues in its DegQ-sensitive domains, ND1 and CD0. Therefore, differential regulation by DegQ and FlaJ controls the cytoplasmic stability of flagellins, which further determines the motility-dependent, stage-specific development of biofilms.