BACKGROUND: It has been frequently reported that non-negligible numbers of individuals have steady-state visual evoked potential (SSVEP) responses of low signal-to-noise-ratio (SNR) to specific stimulation frequencies, which makes detection of the SSVEP difficult especially in brain–computer interface applications. We investigated whether SSVEP can be modulated by anodal transcranial direct-current stimulation (tDCS) of the visual cortex. METHODS: Each participant participated in two 20-min experiments—an actual tDCS experiment and a sham tDCS experiment—that were conducted on different days. Two representative electroencephalogram (EEG) features used for the SSVEP detection, SNR and amplitude, were tested for pre- and post-tDCS conditions to observe the effect of the anodal tDCS. RESULTS: The EEG features were significantly enhanced by the anodal tDCS for the electrodes with low pre-tDCS SNR values, whereas the effect was not significant for electrodes with relatively higher SNR values. CONCLUSION: Anodal tDCS of the visual cortex may be effective in enhancing the SNR and amplitude of the SSVEP response especially for individuals with low-SNR SSVEP.
Electrodes ; Electroencephalography ; Evoked Potentials, Visual ; Transcranial Direct Current Stimulation ; Visual Cortex

Background: The rate and composition of bacterial co-infection in patients with coronavirus disease 2019 (COVID-19) were evaluated when microbiological testing was conducted on the majority of patients. We also evaluated whether the use of empirical antibacterials was associated with mortality. Methods: In this retrospective study, all of the adult patients with COVID-19 hospitalized in a single tertiary hospital in South Korea between February 2020 and December 2021 were included. Bacterial co-infection was assessed by sputum cultures, blood cultures, and molecular testing, including polymerase chain reaction sputum testing and urinary antigen tests. Mortality was compared between patients who received empirical antibacterials and those who did not. Results: Of the 367 adult patients admitted during the study period, 300 (81.7%) had sputum culture results and were included in the analysis. Of these 300 patients, 127 (42.3%) had a history of antibiotic exposure. The co-infection rate within 48 hours was 8.3% (25/300):6.4% (11/173) of patients without prior antibiotic exposure and 11% (14/127) of patients with prior antibacterial exposure. The co-infected bacteria were different according to antibacterial exposure before admission, and multi-drug resistant pathogens were detected exclusively in the antibacterial exposed group. Among the patients without positive results for the microbiological tests, empirical antibacterials were used in 33.3% of cases (100/300). Empirical antibacterial therapy was not significantly related to the 30-day mortality or inhospital mortality rates in the study cohort before or after the propensity score-matching. Conclusion In this study including only patients underwent microbiological testing, bacterial co-infection was not frequent, and the co-infected organisms varied depending on previous antibacterial exposures. Given the rarity of co-infection and the lack of potential benefits, empiric antibacterial use in COVID-19 should be an important target of antibiotic stewardship.

Background: Sequence type 72 (ST72) is the predominant community-associated methicillin-resistant Staphylococcus aureus (MRSA) genotype in Korea. With an increasing prevalence of the ST72 S. aureus lineage, regardless of methicillin resistance, it is crucial to understand the clinical and microbiological characteristics of ST72 methicillin-susceptible S. aureus (MSSA) as well as ST72 MRSA. Materials and Methods: In this retrospective cohort study, data from patients with S. aureus bacteremia (SAB) who were admitted to a tertiary hospital in Korea from March 2007 to December 2018 were collected. Multilocus sequence typing was used to identify ST72 isolates. The clinical and microbiological characteristics of ST72 MSSA were compared with those of ST72 MRSA among patients infected with SAB. Results: Among the 442 SAB patients with ST72, 157 (35.5%) were infected with MSSA and 285 (64.5%) were infected with MRSA. There was a significant increase in the proportion of ST72 MSSA in both the community and hospital settings. Compared to ST72 MRSA, ST72 MSSA isolates were less likely to have multidrug resistance. The main infection foci, infection severity, and duration of bacteremia did not differ significantly between the two groups.The 90-day recurrence rate was significantly lower in the MSSA group (2.5% vs. 8.4%, P=0.03), while the 90-day mortality rate was comparable (28.0% vs. 23.9%, P=0.40). Conclusion ST72 MSSA had similar clinical features as ST72 MRSA in terms of infection site, severity, and 90-day mortality. Despite exhibiting lower levels of antibiotic resistance, ST72 MSSA has increased in the hospital environment concurrently with ST72 MRSA.

Background: Sequence type 72 (ST72) is the predominant community-associated methicillin-resistant Staphylococcus aureus (MRSA) genotype in Korea. With an increasing prevalence of the ST72 S. aureus lineage, regardless of methicillin resistance, it is crucial to understand the clinical and microbiological characteristics of ST72 methicillin-susceptible S. aureus (MSSA) as well as ST72 MRSA. Materials and Methods: In this retrospective cohort study, data from patients with S. aureus bacteremia (SAB) who were admitted to a tertiary hospital in Korea from March 2007 to December 2018 were collected. Multilocus sequence typing was used to identify ST72 isolates. The clinical and microbiological characteristics of ST72 MSSA were compared with those of ST72 MRSA among patients infected with SAB. Results: Among the 442 SAB patients with ST72, 157 (35.5%) were infected with MSSA and 285 (64.5%) were infected with MRSA. There was a significant increase in the proportion of ST72 MSSA in both the community and hospital settings. Compared to ST72 MRSA, ST72 MSSA isolates were less likely to have multidrug resistance. The main infection foci, infection severity, and duration of bacteremia did not differ significantly between the two groups.The 90-day recurrence rate was significantly lower in the MSSA group (2.5% vs. 8.4%, P=0.03), while the 90-day mortality rate was comparable (28.0% vs. 23.9%, P=0.40). Conclusion ST72 MSSA had similar clinical features as ST72 MRSA in terms of infection site, severity, and 90-day mortality. Despite exhibiting lower levels of antibiotic resistance, ST72 MSSA has increased in the hospital environment concurrently with ST72 MRSA.

Background: Sequence type 72 (ST72) is the predominant community-associated methicillin-resistant Staphylococcus aureus (MRSA) genotype in Korea. With an increasing prevalence of the ST72 S. aureus lineage, regardless of methicillin resistance, it is crucial to understand the clinical and microbiological characteristics of ST72 methicillin-susceptible S. aureus (MSSA) as well as ST72 MRSA. Materials and Methods: In this retrospective cohort study, data from patients with S. aureus bacteremia (SAB) who were admitted to a tertiary hospital in Korea from March 2007 to December 2018 were collected. Multilocus sequence typing was used to identify ST72 isolates. The clinical and microbiological characteristics of ST72 MSSA were compared with those of ST72 MRSA among patients infected with SAB. Results: Among the 442 SAB patients with ST72, 157 (35.5%) were infected with MSSA and 285 (64.5%) were infected with MRSA. There was a significant increase in the proportion of ST72 MSSA in both the community and hospital settings. Compared to ST72 MRSA, ST72 MSSA isolates were less likely to have multidrug resistance. The main infection foci, infection severity, and duration of bacteremia did not differ significantly between the two groups.The 90-day recurrence rate was significantly lower in the MSSA group (2.5% vs. 8.4%, P=0.03), while the 90-day mortality rate was comparable (28.0% vs. 23.9%, P=0.40). Conclusion ST72 MSSA had similar clinical features as ST72 MRSA in terms of infection site, severity, and 90-day mortality. Despite exhibiting lower levels of antibiotic resistance, ST72 MSSA has increased in the hospital environment concurrently with ST72 MRSA.

Background: Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection is not differentiated clinically from other respiratory infections, and intensive care units (ICUs) are vulnerable to in-hospital transmission due to interventions inducing respiratory aerosols.This study evaluated the effectiveness of universal SARS-CoV-2 screening in ICUs in terms of screened-out cases and reduction in anxiety of healthcare personnel (HCP).Materials and Methods: This prospective single-armed observational study was conducted in 2 ICUs of a single hospital. The number of patients diagnosed with SARS-CoV-2 infection by the screening program and healthcare workers in ICUs that visited the SARS-CoV-2 screening clinic or infection clinic were investigated. Results: During the 7-week study period, no positive screening case was reported among a total of 142 patients. Among 86 HCP in the ICUs, only 2 HCP sought medical consultation for SARS-CoV-2 infection during the initial 2 weeks. Conclusion A universal screening program for SARS-CoV-2 infection in ICUs with the coordination of other countermeasures in the hospital was reasonably effective in preventing in-hospital transmission in a pandemic situation and making clinical practices and HCP stable.

We evaluated the Standard Q COVID-19 Ag test for the diagnosis of coronavirus disease 2019 (COVID-19) compared to the reverse transcription-polymerase chain reaction (RT-PCR) test.We applied both tests to patients who were about to be hospitalized, had visited an emergency room, or had been admitted due to COVID-19 confirmed by RT-PCR. Two nasopharyngeal swabs were obtained; one was tested by RT-PCR and the other by the Standard Q COVID-19 Ag test. A total of 118 pairs of tests from 98 patients were performed between January 5 and 11, 2021. The overall sensitivity and specificity for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) for the Standard Q COVID-19 Ag test compared to RT-PCR were 17.5% (95% confidence interval [CI], 8.8–32.0%) and 100% (95% CI, 95.3–100.0%). Analysis of the results using RT-PCR cycle thresholds of ≤ 30 or ≤ 25 increased the sensitivity to 26.9% (95% CI, 13.7–46.1%), and 41.1% (95% CI, 21.6–64.0%), respectively.

Applying work restrictions for asymptomatic healthcare personnel (HCP) with potential exposure to coronavirus disease 2019 (COVID-19) is recommended to prevent transmission from potentially contagious HCP to patients and other HCP. However, it can lead to understaffing, which threatens the safety of both patients and HCP. We evaluated 203 COVID-19 exposure events at a single tertiary hospital from January 2020 to June 2021. A total of 2,365 HCP were potentially exposed, and work restrictions were imposed on 320 HCP, leading to the loss of 3,311 working days. However, only one of the work-restricted HCP was confirmed with COVID-19. During the study period, the work restriction measures might be taken excessively compared to their benefit, so establishing more effective standards for work restriction is required.

We evaluated the Standard Q COVID-19 Ag test for the diagnosis of coronavirus disease 2019 (COVID-19) compared to the reverse transcription-polymerase chain reaction (RT-PCR) test.We applied both tests to patients who were about to be hospitalized, had visited an emergency room, or had been admitted due to COVID-19 confirmed by RT-PCR. Two nasopharyngeal swabs were obtained; one was tested by RT-PCR and the other by the Standard Q COVID-19 Ag test. A total of 118 pairs of tests from 98 patients were performed between January 5 and 11, 2021. The overall sensitivity and specificity for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) for the Standard Q COVID-19 Ag test compared to RT-PCR were 17.5% (95% confidence interval [CI], 8.8–32.0%) and 100% (95% CI, 95.3–100.0%). Analysis of the results using RT-PCR cycle thresholds of ≤ 30 or ≤ 25 increased the sensitivity to 26.9% (95% CI, 13.7–46.1%), and 41.1% (95% CI, 21.6–64.0%), respectively.

Applying work restrictions for asymptomatic healthcare personnel (HCP) with potential exposure to coronavirus disease 2019 (COVID-19) is recommended to prevent transmission from potentially contagious HCP to patients and other HCP. However, it can lead to understaffing, which threatens the safety of both patients and HCP. We evaluated 203 COVID-19 exposure events at a single tertiary hospital from January 2020 to June 2021. A total of 2,365 HCP were potentially exposed, and work restrictions were imposed on 320 HCP, leading to the loss of 3,311 working days. However, only one of the work-restricted HCP was confirmed with COVID-19. During the study period, the work restriction measures might be taken excessively compared to their benefit, so establishing more effective standards for work restriction is required.