The most important characteristics of coronavirus disease 2019 (COVID-19) transmission that makes it difficult to control are 1) asymptomatic and presymptomatic transmission, 2) low incidence or lack of dominant systemic symptoms such as fever, 3) airborne transmission that may need a high infectious dose, and 4) super-spread events (SSEs). Patients with COVID-19 have high viral loads at symptom onset or even a few days prior to symptom onset, and most patients with COVID-19 have only mild respiratory symptoms or merely pauci-ull-symptoms. These characteristics of the virus enable it to easily spread to the community because most patients are unaware of their potential infectivity, and symptombased control measures cannot prevent this type of transmission. Furthermore, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is also capable of airborne transmission in conditions such as aerosol-generating procedures, under-ventilated indoor spaces, and over-crowded areas. In this context, universal mask-wearing is important to prevent both outward and inward transmission until an adequate degree of herd immunity is achieved through vaccination. Lastly, the SSEs of SARS-CoV-2 transmission emphasize the importance of reducing contacts by limiting social gatherings. The above-mentioned transmission characteristics of SARS-CoV-2 have culminated in the failure of long-lasting quarantine measures, and indicate that only highly effective vaccines can keep the communities safe from this deadly, multifaceted virus.

Background and Objectives: Traditionally, transoral laser microsurgery (TLM) is commonly used to treat early glottic cancer. However, the long-term oncologic results have not been thoroughly investigated. Therefore, this study aimed to analyze long-term oncologic outcomes of TLM for early glottic cancer.Subjects and Method We retrospectively studied 132 patients who underwent TLM for early glottis cancer from January 2001 to August 2020. We assessed overall and disease-free survival according to the T classification and types of cordectomy proposed by the European Laryngological Society in 2007. Results: Of the 132 patients, 125 were male and 7 female. The mean age was 61.6±9.3 years. We found 5 (3.8%), 112 (84.8%), and 15 (11.3%) patients staged as CIS, T1, and T2, respectively. For the cordectomy types, there were 6 in type I, 22 in type II, 83 in type III, 6 in type IV, 13 in type V, and 2 in type VI. Ten-year overall and disease-free survival rates were 99.2% and 87.1%, respectively. Overall and disease-free survival curves were not different according to different T classification and cordectomy types. Conclusion TLM is an excellent treatment modality for the long-term oncologic control of early glottic cancer.

The seropositivity of measles antibodies among 261 autologous stem cell transplant recipients (ASCTs) in Korea, assessed approximately 1–2 years after transplant (median, 11 months; interquartile range, 9–14), was significantly lower than age- and sex-matched control healthcare workers (83.1% [217/261] vs. 90.3% [539/597], P = 0.002). The findings underscore the vulnerability of adult ASCT recipients to measles. Clinicians should prioritize testing for measles IgG after ASCT and consider vaccination for ASCT recipients who remain seronegative 2 years after ASCT.

Toxocariasis is an important cause of secondary hypereosinophilia in Korea. Here, we describe a rare case of toxocariasis presenting as transient global amnesia due to secondary hypereosinophilia. A 44-year-old male visited the Emergency Department (ED) for transient global amnesia. He ate raw cow liver and omasum 2 weeks before the ED visit. The initial peripheral blood eosinophil count was 15,250/µL and serologic test for serum specific IgG antibodies to Toxocara canis larval antigen was positive. Radiologic studies revealed multiple small embolic infarctions of brainwithout cardioembolic sources or vascular abnormalities. He was treated with systemic corticosteroid, and neither neurologic deficit nor motor deficit was left. In our current case, the patient have a history of frequently eating raw cow liver and omasum, and his total IgE level was extremely high (>5,000 IU/mL). Thus, the patient was diagnosed as having toxocariasis and secondary hypereosinophilia. Toxocariasis should be considered in the differential diagnosis in patients with eosinophilia and atypical neurologic symptoms, such as transient amnesia.
Adult ; Amnesia ; Amnesia, Transient Global* ; Antibodies ; Cerebral Infarction ; Diagnosis, Differential ; Eating ; Emergency Service, Hospital ; Eosinophilia ; Eosinophils ; Humans ; Immunoglobulin E ; Immunoglobulin G ; Infarction ; Korea ; Liver ; Male ; Neurologic Manifestations ; Omasum ; Serologic Tests ; Toxocara canis ; Toxocariasis*

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/Aims: Data comparing the antibody responses of different coronavirus disease 2019 (COVID-19) vaccine platforms according to dose with natural severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection-induced antibody responses are limited. Methods: Blood samples from adult patients with mild and severe COVID-19 and healthcare workers who received ChAdOx1 nCoV-19 vaccine (2nd dose at 12-week intervals) and BNT162b2 vaccine (2nd dose at 3-week intervals) were collected and compared by immunoglobulin G immune responses to SARS-CoV-2 specific spike protein using an in-house-developed enzyme-linked immunosorbent assay. Results: A total of 53 patients, including 12 and 41 with mild and severe COVID-19, respectively, were analyzed. In addition, a total of 73 healthcare workers, including 37 who received ChAdOx1 nCoV-19 and 36 who received BNT162b2, were enrolled. Antibody responses after the first and second doses of the ChAdOx1 nCoV-19 vaccine or the first dose of the BNT162b2 vaccine were similar to those in convalescent patients with mild COVID-19, but lower than those in convalescent patients with severe COVID-19, respectively. However, after the second dose of the BNT162b2 vaccine, the antibody response was comparable to that in convalescent patients with severe COVID-19. Conclusions Our data suggest that the second dose of mRNA vaccination may be more beneficial in terms of long-term immunity and prevention of SARS-CoV-2 variant infection than a single dose of COVID-19 vaccination or homologous second challenge ChAdOx1 nCoV-19.

Background/Aims: Multi-drug resistant pathogens are increasing among healthcare-associated infections. It is well known that copper and copper alloys have antimicrobial activity. We evaluated the activity of copper against bacteria in a hospital setting in Korea. Methods: This study was conducted in a laboratory and medical intensive care unit (ICU). Methicillin resistant Staphylococcus aureus (MRSA) and vancomycin resistant Enterococcus faecium (VRE) were inoculated onto copper, copper alloy and stainless steel plates. After 24 hours of incubation, colony-forming units (CFU) were counted in the laboratory. Two similar rooms were chosen in the ICU; one room had copper-containing surface, and the other room contained items with a stainless steel surfaces. Items were sampled weekly for 8 weeks when the rooms were not crowded and when the rooms were busier with healthcare workers or visitors. Results: In vitro time-kill curves showed copper or, a copper alloy yielded a significant reduction in MRSA and VRE CFUs over 15 minutes. Upon exposure to stainless steel plates, CFUs were slowly reduced for 24 hours. In vivo, MRSA CFUs were lower in rooms with copper-containing surfaces compared with controls, both after cleaning and after patients had received visitors (p < 0.05). Analysis of VRE revealed similar results, but VRE CFUs from copper-containing surfaces of drug carts in the ICU did not decrease significantly. Conclusions Copper has antimicrobial activity and appears to reduce the number of multi-drug resistant microorganisms in a hospital environment. This finding suggests the potential of the use of copper fittings, instruments and surfaces in hospital.

Background: Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacterales bacteremia is associated with significant mortality; however, no optimal antibiotic strategy is available. We aimed to evaluate the clinical outcomes according to the antibiotic regimens and identify risk factors for mortality in patients with KPC-producingK. pneumoniae and Escherichia coli bacteremia. Materials and Methods: This retrospective cohort study included all adult patients with monomicrobial bacteremia (KPC-producing K. pneumoniae or E. coli) between January 2011 and March 2021 at a 2,700-bed tertiary center. Results: Ninety-two patients were identified; 7 with E. coli bacteremia, and 85 with K. pneumoniae bacteremia. Thirty-day mortality was 38.0% (35/92). Non-survivors were more likely to have had nosocomial infection (88.6% vs. 63.2%, P = 0.01), high APACHE II scores (mean [interquartile range], 22.0 [14.0 - 28.0] vs. 14.0 [11.0 - 20.5],P <0.001), and septic shock (51.4% vs. 26.3%, P <0.001) and less likely to have been admitted to the surgical ward (5.7% vs. 22.8%, P= 0.04), undergone removal of eradicable foci (61.5% vs. 90.6%, P = 0.03), and received appropriate combination treatment (57.1% vs. 78.9%, P = 0.03) than survivors. No significant difference in mortality was observed according to combination regimens including colistin, aminoglycoside, and tigecycline. In multivariable analysis, high APACHE II scores (adjusted odds ratio [aOR], 1.14; 95% confidence interval [CI], 1.06 - 1.23, P <0.001), and appropriate definitive treatment (aOR, 0.25; CI, 0.08 - 0.74,P = 0.01) were independent risk factors for mortality. Conclusion High APACHE II scores and not receiving appropriate definitive treatment were associated with 30-day mortality. Mortality did not significantly differ according to combination regimens with conventional drugs such as aminoglycoside and colistin.

Background/Aims: The rapidity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific memory B or T cell response in vaccinated individuals is important for our understanding of immunopathogenesis of coronavirus disease 2019 (COVID-19). We therefore compared the timing of adequate immune responses between the first and booster doses of COVID-19 vaccines in infection-naïve healthcare workers. Methods: We enrolled healthcare workers who received two doses of either the BNT162b2 vaccine or the ChAdOx1 vaccine, all of whom received the BNT162b2 vaccine as the booster (the third) dose. Spike 1 (S1)-immunoglobulin G (IgG) antibodies and interferon gamma producing T cell responses were measured at 0, 7, 14, and 21 days after the first dose, and at 0 and between 2 to 7 days after the booster dose. Results: After the first-dose vaccination, the S1-IgG antibody responses were elicited within 14 days in the BNT162b2 group and within 21 days in the ChAdOx1 group. After the booster dose, the S1-IgG antibody responses were elicited within 5 days in both groups. The SARS-CoV-2-specific T cell responses appeared at 7 days after the first dose and at 4 days after the booster dose. Conclusions SARS-CoV-2-specific immune responses by memory B cells and T cells may be expected to appear around 4 to 5 days after the booster dose.

Background/Aims: Multi-drug resistant pathogens are increasing among healthcare-associated infections. It is well known that copper and copper alloys have antimicrobial activity. We evaluated the activity of copper against bacteria in a hospital setting in Korea. Methods: This study was conducted in a laboratory and medical intensive care unit (ICU). Methicillin resistant Staphylococcus aureus (MRSA) and vancomycin resistant Enterococcus faecium (VRE) were inoculated onto copper, copper alloy and stainless steel plates. After 24 hours of incubation, colony-forming units (CFU) were counted in the laboratory. Two similar rooms were chosen in the ICU; one room had copper-containing surface, and the other room contained items with a stainless steel surfaces. Items were sampled weekly for 8 weeks when the rooms were not crowded and when the rooms were busier with healthcare workers or visitors. Results: In vitro time-kill curves showed copper or, a copper alloy yielded a significant reduction in MRSA and VRE CFUs over 15 minutes. Upon exposure to stainless steel plates, CFUs were slowly reduced for 24 hours. In vivo, MRSA CFUs were lower in rooms with copper-containing surfaces compared with controls, both after cleaning and after patients had received visitors (p < 0.05). Analysis of VRE revealed similar results, but VRE CFUs from copper-containing surfaces of drug carts in the ICU did not decrease significantly. Conclusions Copper has antimicrobial activity and appears to reduce the number of multi-drug resistant microorganisms in a hospital environment. This finding suggests the potential of the use of copper fittings, instruments and surfaces in hospital.