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Background There is a global increase in isolation of nontuberculous mycobacteria (NTM). The aim of the study was to analyze longitudinal trends of NTM identification and pattern of antimicrobial susceptibility testing. Methods NTM recovery rates, distribution of NTM species identification, and antimicrobial susceptibility pattern of NTM at Pusan National University Yangsan Hospital between January 2016 and December 2020 were retrospectively analyzed. Results A total of 52,456 specimens from 21,264 patients were submitted for mycobacterial culture, of which 2,521 from 1,410 patients were NTM positive over five years (January 2016 to December 2020). NTM isolation showed an increasing trend from 2016 to 2020 (p

Background: Understanding the immune response to evolving viral strains is crucial for evidence-informed public health strategies. The main objective of this study is to assess the influence of vaccination on the neutralizing activity of SARS-CoV-2 delta and omicron infection against various SARS-CoV-2 variants. Methods: A total of 97 laboratory-confirmed COVID-19 cases were included. To assess the influence of vaccination on neutralizing activity, we measured the neutralizing activity of SARS-CoV-2 delta or omicron (BA.1 or BA.2) infection against wild-type (WT), delta, BA.1, and BA.2, with the results stratified based on vaccination status. Results: The neutralizing activity against the WT, delta, and omicron variants (BA.1 and BA.2) was significantly higher in the vaccinated patients than those in the unvaccinated patients. In the unvaccinated individuals infected with the delta variant, the decrease in binding to BA.1 and BA.2 was statistically significant (3.9- and 2.7-fold, respectively) compared to the binding to delta. In contrast, vaccination followed by delta breakthrough infection improved the cross-neutralizing activity against omicron variants, with only 1.3- and 1.2-fold decreases in BA.1 and BA.2, respectively. Vaccination followed by infection improved cross-neutralizing activity against WT, delta, and BA.2 variants in patients infected with the BA.1 variant, compared to that in unvaccinated patients. Conclusions: Vaccination followed by delta or BA.1 infection is associated with improved cross-neutralizing activity against different SARS-CoV-2 variants. The enhanced protection provided by breakthrough infections could have practical implications for optimizing vaccination strategies.

ABSTRACT Nasopharyngeal swabs (NPS) or washings have traditionally been used to diagnose respiratory tract infections. Reverse transcriptase PCR (RT-PCR) is widely used for rapid viral detection using samples from the upper respiratory tract. However, RT-PCR is rarely applied to sputum samples, mainly due to the viscosity of sputum. Thus, we assessed the detection rates of respiratory viruses from NPS, sputum samples, and combined NPS and sputum samples using multiplex RT-PCR (Allplex respiratory panels I, II, and III; Seegene, Seoul, South Korea). Paired NPS and sputum samples were collected from 219 patients admitted to the hospital with acute respiratory illnesses from October to December 2019. RT-PCR was performed on each sample for virus detection. Combined samples for virus detection were produced using remnant NPS and sputum samples with a positive virus signal. Respiratory viral nucleic acid was identified in 92 (42%) of 219 patients. Among the 92 viral detections, 61 (28%) were detected by both NPS and sputum samples. Twenty-four (11%) were sputum positive/NPS negative, and seven (3%) were sputum negative/NPS positive. For the combined NPS-sputum samples (n = 92), all paired samples positive in both specimens (n = 61) were also positive in the combined NPS-sputum sample. Twenty-seven (87%) of the 31 discordant paired samples were positive in the combined samples. Out of the total of 103 viruses identified before combining the samples, the detection rate of the combined samples was 94% (97/103), which was higher than the detection rates of sputum (88%; 91/103) and NPS (71%; 73/103). Because additional tests incur additional costs, our findings suggest that combining samples instead of testing separate samples using RT-PCR is likely the most cost-effective method of viral testing for patients with acute respiratory illnesses. IMPORTANCE This study reveals that RT-PCR utilizing sputum significantly increased the detection rate for respiratory viral nucleic acids among adult patients admitted to the hospital, compared to nasopharyngeal swabs (NPS). Notably, combined samples of sputum and NPS maintained the majority of the improved sputum detection rate with only a few positive signal losses from NPS samples. In order to detect respiratory viruses in adult patients with acute respiratory illness, it is important to choose the optimal respiratory samples. This study helped to improve our understanding of this process.

Background and Objectives: This study aimed to evaluate the performance of a new chemiluminescent immunoassay-based tuberculosis (TB) interferon-gamma release assay (IGRA), AdvanSureI3 TB-IGRA (LG Chem Ltd., Seoul, Republic of Korea), for detecting latent tuberculosis infection in comparison with T-SPOT.TB (Oxford Immunotec, Oxford, UK). Materials and Methods: Between June 2021 and December 2021, 125 non-duplicate blood specimens were collected from adult volunteers; each subject received both tests concurrently. Total agreement and Cohen’s kappa coefficient (κ) were used to calculate concordance. The Jonckheere–Terpstra test was used to examine the correlation between interferon-gamma (IFN-γ) levels in AdvanSureI3 TB-IGRA and spot counts in T-SPOT.TB. Results: The IGRA findings of the two assays revealed 90.8% (95% confidence interval [CI] = 84.2–94.8) total agreement with κ of 0.740 (95% CI = 0.595–0.885), showing substantial agreement between the two tests. Additionally, the amount of IFN-γ in AdvanSureI3 TB-IGRA increased with the spot counts in T-SPOT.TB (p < 0.001). Conclusions: Our research revealed that the results of the AdvanSureI3 TB-IGRA were comparable to those of T-SPOT.TB.

Background: The goal of this study was to develop and validate a UPLC-MS/MS method for simultaneous measurement of 13 AEDs, including carbamazepine, oxcarbazepine, lamotrigine, levetiracetam, topiramate, primidone, zonisamide, gabapentin, lacosamide, perampanel, pregabalin, rufinamide, and vigabatrin, in whole blood samples. Methods: A UPLC-MS/MS method for simultaneous determination of 13 AEDs in whole blood was developed, and validation was conducted for accuracy, precision, limit of quantification (LOQ), matrix effect, and stability. Our method was compared to two different hospitals using UPLC-MS/MS. Results: All AEDs exhibited linearity across the AMR (analytical measurement range), with R² values ranging from 0.994 to 1.000. The imprecision and inaccuracy for low and high quality control (QC) levels were within an acceptable range, with the coefficient of variation (CV) < 15%. The LOQ was 0.62 μg/mL for carbamazepine, 1.61 μg/mL for oxcarbazepine, 1.30 μg/mL for lamotrigine, 13.20 μg/mL for levetiracetam, 1.26 μg/mL for topiramate, 1.01 μg/mL for primidone, 1.59 μg/mL for zonisamide, 1.09 μg/mL for lacosamide, 1.61 μg/mL for gabapentin, 0.50 μg/mL for pregabalin, 0.07 ng/mL for perampanel, 3.00 μg/mL for rufinamide, and 2.06 μg/mL for vigabatrin. All AEDs demonstrated acceptable assay parameters for carryover, stability, and matrix effects. Moreover, the assay showed satisfactory results compared to two different hospitals with a bias of less than 15%. Conclusions: We successfully developed and validated a fast and robust UPLC-MS/MS method for routine therapeutic drug monitoring of thirteen antiepileptic drugs simultaneously. [ABSTRACT FROM AUTHOR]

Background: There is little data about the performance of multiplex rapid antigen tests (RATs) on the detection of SARS-CoV-2, influenza A (Flu A), and influenza B (Flu B). This study is to evaluate the performance of Panbio COVID-19/Flu A&B rapid panel (Abbott Diagnostics, Korea) and analyze the factors influencing its sensitivity. Methods: Nasopharyngeal swabs were collected and stored at the Korea University Anam hospital. In total, 400 residual samples from nasopharyngeal swabs were examined. The diagnostic accuracy of RAT was compared to that of RT-qPCR using the Allplex SARS-CoV-2/FluA/FluB/RSV Assay (Seegene, Seoul, South Korea). Results: Panbio COVID-19/Flu A&B rapid panel showed the sensitivities of 88.0%, 92.0%, and 100% for SARS-CoV-2, Flu A, and Flu B, respectively, and specificities of 100% for all. The agreements with previously licensed single-plex RATs were shown to be high. In the analysis of variables affecting sensitivity, inappropriate sampling time after symptom onset (STASO) and high cycle threshold (Ct value) were shown to negatively affect the sensitivity. Conclusions: In conclusion, the multiplex RAT is useful for diagnosing SARS-CoV-2 and Flu A/B, but more clinical studies are needed. [ABSTRACT FROM AUTHOR]

Background: Therapeutic drug monitoring (TDM) of antifungal drugs is recommended. LC-MS/MS outperforms bioassay and high-performance liquid chromatography (HPLC) for TDM. In this study, we validated TDM for voriconazole, posaconazole, and itraconazole using HPLC-MS/MS with the multiple reaction monitoring (MRM) method. Methods: For the validation of LC-MS/MS for antifungal TDM, accuracy, precision, linearity, carryover, lower limit of quantitation (LLOQ), ion suppression, and sample stability tests were performed according to the guidelines of the United States Food and Drug Administration (FDA) and the Clinical and Laboratory Standards Institute (CLSI). Results: The LC-MS/MS triazole method showed that all analytes had biases less than 8.9% and coefficients of variation (CV) less than 7.7%. The linearity was validated over the ranges of 0.20 to 5.86 mg/L for voriconazole, 0.12 to 4.96 mg/L for posaconazole, 0.09 to 1.85 mg/L for itraconazole, and 0.12 to 2.38 mg/L for OH-itraconazole. Ion suppression and carryover were negligible. The lower limits of quantitation (LLOQs) for voriconazole, posaconazole, itraconazole, and OH-itraconazole were 0.114 mg/L, 0.206 mg/L, 0.118 mg/L, and 0.065 mg/L, respectively. Voriconazole, posaconazole, itraconazole, and OH-itraconazole can be stored at 4? for 4 - 7 days, according to sample stability. Sample preparation took < 15 minutes per batch, and analytical run time was 5 minutes per sample. Conclusions: We developed and validated a simple, reliable, and quick LC-MS/MS method for triazole antifungal agents TDM suitable for routine hospital practice. [ABSTRACT FROM AUTHOR]

The absorption and dispersion of aligned single-walled carbon-nanotube films were measured from 0.2 to 2.0 THz using a source of freely propagating subpicosecond pulses of THz electromagnetic radiation. The real conductivity increased rapidly with increasing frequency up to 0.45 THz and decreased at a high-frequency range. The Maxwell-Garnett model, where the nanotubes were embedded in a dielectric host, fit the results of this study with the Drude-Lorentz model for nanotube network. We have observed the transverse phonon mode of 2.4 THz propagating along the c direction. This suggested that the carbon nanotube network is composed of metallic and semiconducting nanotubes embedded in an air dielectric host. [ABSTRACT FROM AUTHOR]