Real World Experience with Regdanvimab Treatment of Mild-toModerate Coronavirus Disease-19 in a COVID-19 Designated Hospital of Korea

Background@#Real-world clinical data concerning regdanvimab, a monoclonal antibody treatment for patients with mild-to-moderate coronavirus disease 2019 (COVID-19), are urgently needed. Here, we describe our experience with regdanvimab. @*Materials and Methods@#This retrospective cohort study enrolled high-risk adults with mild-to-moderate COVID-19 who were admitted to a dedicated COVID-19 hospital in Korea from March to September 2021. We used multiple logistic regression and propensity scorematching to compare the outcomes of patients who did or did not receive regdanvimab. The primary outcome was in-hospital progression to severe or critical status, or death. @*Results@#Of 586 patients eligible for regdanvimab, 256 patients who received regdanvimab and 251 untreated patients were included. The median age was 66 years and 47.5% were men. The most common underlying illnesses were hypertension (53.8%) and diabetes (36.9%). Patients were admitted to the hospital at a median of 2 days after symptom onset; regdanvimab was administered at a median of 3 days after symptom onset. Multivariate analysis indicated that regdanvimab significantly reduced the risk of disease progression during hospitalization [odds ratio (OR): 0.285; 95% confidence interval (CI): 0.144 - 0.564].In a 1:1 propensity score-matched cohort (172 patients in either group), regdanvimab also decreased the risk of progression (OR: 0.162; 95% CI: 0.068 - 0.386). @*Conclusion@#In high-risk patients with mild-to-moderate COVID-19, regdanvimab decreased the risk of progression to severe COVID-19.

Clinical Features of Adult COVID-19 Patients without Risk Factors before and after the Nationwide SARSCoV-2 B.1.617.2 (Delta)-variant Outbreak in Korea: Experience from Gyeongsangnam-do

Background@#Data on severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) delta variant virulence are insufficient. We retrospectively compared the clinical features of adult coronavirus disease 2019 (COVID-19) patients without risk factors for severe COVID-19 who entered residential treatment centers (RTCs) before and after the delta variant outbreak. @*Methods@#We collected medical information from two RTCs in South Korea. On the basis of nationwide delta variant surveillance, we divided the patients into two groups: 1) the delta-minor group (diagnosed from December 2020–June 2021, detection rate 90%). After propensity-score matching, the incidences of pneumonia, hospital transfer and need for supplemental oxygen were compared between the groups. In addition, risk factors for hospital transfer were analysed. @*Results@#A total of 1,915 patients were included. The incidence of pneumonia (14.6% vs.9.2%, P = 0.009), all-cause hospital transfer (10.4% vs. 6.3%, P = 0.020) and COVID-19-related hospital transfer (7.5% vs. 4.8%, P = 0.081) were higher in the delta-dominant group than those in the delta-minor group. In the multivariate analysis, the delta-dominant group was an independent risk factor for all-cause (adjusted odds ratio [aOR], 1.91; 95% confidence interval [CI], 1.16–3.13; P = 0.011) and COVID-19-related hospital transfer (aOR, 1.86; 95% CI, 1.04–3.32; P = 0.036). @*Conclusion@#Hospitalization rates were increased in the adult COVID-19 patients during the delta variant nationwide outbreak. Our results showed that the delta variant may be more virulent than previous lineages.

Etiology, Characteristics, and Outcomes of Community-Onset Pyomyositis in Korea: A Multicenter Study

Background@#Pyomyositis (PM) is a serious soft tissue infection and despite its clinical importance, previous studies have not been able to fully determine the clinical characteristics and microbial epidemiology of PM in Korea, which we therefore aimed to investigate. @*Materials and Methods@#We retrospectively identified 140 adult patients diagnosed with PM from 13 general hospitals between January 2012 and December 2015. We analyzed the clinical and microbial characteristics of community-onset PM and compared them with communityacquired (CA) and healthcare-associated (HCA) PM. @*Results@#One hundred eleven organisms were isolated from 96 (68.6%) patients with PM.Staphylococcus aureus (38 patients) was the most common pathogen, followed by streptococci (24 patients), and enteric Gram-negative organisms (27 patients). Methicillin-resistant S.aureus (MRSA) was identified in four (2.9%) patients and in-hospital mortality reached 8.6% (12/140). Enterococci isolates were identified in the HCA PM subgroup only The proportion of MRSA isolates was not comparable between CA and HCA PM subgroups. In the 83 patients with PM infected by monomicrobial pathogens, isolates of Gram-negative organisms were more commonly found in HCA PM subgroup than in CA PM subgroup (47.6% [10/21] of patients with HCA PM vs. 20.7% [12/58] of patients with CA PM; P = 0.01). @*Conclusion@#Gram-positive cocci such as S. aureus and streptococci were dominant etiologies in community-onset PM, whereas MRSA appears to an uncommon causative organism of PM in Korea. Enteric Gram-negative organisms should also be considered as major etiologies, especially in HCA PM patient population in Korea.

Etiology, Characteristics, and Outcomes of Community-Onset Pyomyositis in Korea: A Multicenter Study

Background@#Pyomyositis (PM) is a serious soft tissue infection and despite its clinical importance, previous studies have not been able to fully determine the clinical characteristics and microbial epidemiology of PM in Korea, which we therefore aimed to investigate. @*Materials and Methods@#We retrospectively identified 140 adult patients diagnosed with PM from 13 general hospitals between January 2012 and December 2015. We analyzed the clinical and microbial characteristics of community-onset PM and compared them with communityacquired (CA) and healthcare-associated (HCA) PM. @*Results@#One hundred eleven organisms were isolated from 96 (68.6%) patients with PM.Staphylococcus aureus (38 patients) was the most common pathogen, followed by streptococci (24 patients), and enteric Gram-negative organisms (27 patients). Methicillin-resistant S.aureus (MRSA) was identified in four (2.9%) patients and in-hospital mortality reached 8.6% (12/140). Enterococci isolates were identified in the HCA PM subgroup only The proportion of MRSA isolates was not comparable between CA and HCA PM subgroups. In the 83 patients with PM infected by monomicrobial pathogens, isolates of Gram-negative organisms were more commonly found in HCA PM subgroup than in CA PM subgroup (47.6% [10/21] of patients with HCA PM vs. 20.7% [12/58] of patients with CA PM; P = 0.01). @*Conclusion@#Gram-positive cocci such as S. aureus and streptococci were dominant etiologies in community-onset PM, whereas MRSA appears to an uncommon causative organism of PM in Korea. Enteric Gram-negative organisms should also be considered as major etiologies, especially in HCA PM patient population in Korea.

Management of carbapenem-resistant Acinetobacter baumannii epidemic in an intensive care unit using multifaceted intervention strategy

BACKGROUND/AIMS: We evaluated the effects of a multifaceted intervention for controlling a carbapenem-resistant Acinetobacter baumannii (CRAB) epidemic in an intensive care unit (ICU) with no restrictions on carbapenem use. METHODS: This study was conducted in a medical ICU between April 2012 and June 2016. The baseline infection control programs included surveillance cultures, contact precautions, and environmental cleaning. However, increases in the detection of CRAB isolates beginning in May 2013 led to the implementation of a new protocol, consisting of universal glove and gown use with daily chlorhexidine bathing for all patients in combination with baseline programs. The efficacy of the intervention was subjected to interrupted time series (ITS) analysis. RESULTS: The multifaceted intervention led to a decrease in the incidence of CRAB from 17.65 to 0.89 cases per 1,000 patient-days, during the study period (p < 0.001). ITS analysis revealed a significant change in the trend of CRAB incidence (–0.413, p < 0.001). Over this same period, mean monthly use of carbapenems increased from 143.54 ± 95.73 to 204.95 ± 78.43 doses per 1,000 patient-days (p = 0.018). CONCLUSIONS: Our multifaceted intervention reduced the incidence of CRAB acquisition in an ICU where carbapenem use was not restricted.

Successful Treatment of Catheter Related Blood Stream Infection By Millerozyma farinosa with Micafungin: A Case Report

Millerozyma farinosa (formerly Pichia farinosa) is halotolerant yeast mainly found in food and ubiquitous in the environment. It was a rare yeast pathogen, but it has recently emerged as a cause of fungemia in immunocompromised patients. Optimal therapy for invasive fungal infection by this pathogen remains unclear. We report a case of catheter related blood stream infection caused by M. farinosa in a 71-year-old patient who recovered successfully after removal of the central venous catheter and treatment with micafungin.

Successful Treatment of Catheter Related Blood Stream Infection By Millerozyma farinosa with Micafungin: A Case Report

Millerozyma farinosa (formerly Pichia farinosa) is halotolerant yeast mainly found in food and ubiquitous in the environment. It was a rare yeast pathogen, but it has recently emerged as a cause of fungemia in immunocompromised patients. Optimal therapy for invasive fungal infection by this pathogen remains unclear. We report a case of catheter related blood stream infection caused by M. farinosa in a 71-year-old patient who recovered successfully after removal of the central venous catheter and treatment with micafungin.

Isolation and Genetic Characterization of Orientia tsutsugamushi from Scrub Typhus Patients in Gyeongsangnam-do, Korea

Orientia tsutsugamushi (O. tsutsugamushi), which is endemic to an Asia-Pacific region, has increased its incidence and caused annually around 10 thousand patients infected with scrub typhus in Korea in the past several years. In the present study, we isolated 44 O. tsutsugamushi from the patients with febrile illness accompanied with or without an eschar in Gyeongsangnam-do, Korea. These isolates were characterized by genetic analysis of the major outer membrane protein, the 56-kDa type-specific antigen (tsa56), which is unique to O. tsutsugamushi. Two types of sequences of tsa56, designated by JJ1 and JJ2, were determined from 37 and 7 isolates of the 44 isolates, respectively. JJ1 and JJ2 showed 74.7~90.8% identity in nucleotide sequence and 66.1~90.5% identity in amino acid sequence with 33 reference strains except for Boryong and Kuroki. JJ1 and JJ2 had 100 and 99.9% nucleotide identity to Boryong strain, and 99.9 and 99.8% to Kuroki, which has been known to be similar to Boryong, respectively. In addition, they showed 77.9~ 81.4% nucleotide identity with the cluster of Gilliam-related genotypes, whereas they showed higher nucleotide identity (89.6~90.8%) with the cluster of Karp-related genotypes. To our knowledge, this is the first report to isolate O. tsutsugamushi and characterize their genotype as the Boryong in Jinju and West Gyeongsangnam-do, Korea, even though it has been reported that the Boryong was the predominant genotype in isolates from chiggers, domestic rodents, and patients in the southern part of Korea. Furthermore, our isolates could be useful source to study on the pathophysiology and epidemiology of scrub typhus in Korea.

Epstein-Barr Virus Associated Hemophagocytic Syndrome after Scrub Typhus Infection

There have been a small number of cases of scrub typhus-associated hemophagocytic syndrome (HPS), most of which were treated successfully using adequate antibiotics. Here, we report a case of Epstein-Barr virus (EBV)-associated HPS after scrub typhus infection that was not improved using antirickettsial treatment. A 73-year-old male who had been diagnosed with scrub typhus according to an eschar and a positive serology was transferred to our institution because of a persistent fever despite 7-day doxycycline therapy. Physical and laboratory data showed hepatosplenomegaly, bicytopenia, hyperferritinemia, and hypofibrinogenemia. A bone marrow examination (BM) revealed hypercellular marrow with hemophagocytosis and histiocyte infiltration. EBV was detected in BM aspirates using polymerase chain reaction. After a diagnosis of HPS was made, the patient was treated successfully using high-dose steroids.

Staphylococcus saprophyticus Bacteremia originating from Urinary Tract Infections: A Case Report and Literature Review

Staphylococcus saprophyticus is a common pathogen of acute urinary tract infection (UTI) in young females. However, S. saprophyticus bacteremia originating from UTI is very rare and has not been reported in Korea. We report a case of S. saprophyticus bacteremia from UTI in a 60-year-old female with a urinary stone treated successfully with intravenous ciprofloxacin, and review the cases of S. saprophyticus bacteremia reported in the literature. Thus, the microorganism may cause invasive infection and should be considered when S. saprophyticus is isolated from blood cultures in patients with UTI.

Bone Marrow Suppression and Hemophagocytic Histiocytes Are Common Findings in Korean Severe Fever with Thrombocytopenia Syndrome Patients

The causes of cytopenia in patients with severe fever with thrombocytopenia syndrome (SFTS) are not fully understood until now. We reviewed the bone marrow (BM) findings of patients with SFTS to unravel the cause of the cytopenia. Three Korean SFTS were enrolled in this study. Thrombocytopenia, neutropenia, and anemia were detected in all three patients. Severe hypocellular marrow (overall cellularity <5%) and a decreased number of megakaryocytes were noted in one patient, and hypo-/normocellular marrow and an increased number of hemophagocytic histiocytes were observed in two patients. Megakaryocytes were relatively preserved in two patients. Although a limited number of cases are available, our observations suggest that both BM suppression and peripheral destruction or sequestration are causes of cytopenia of patients with SFTS. To the best of our knowledge, this is the first well documented pathologic evaluation of Korean SFTS.

Infectious Spondylitis with Bacteremia Caused by Roseomonas mucosa in an Immunocompetent Patient

Roseomonas are a gram-negative bacteria species that have been isolated from environmental sources. Human Roseomonas infections typically occur in immunocompromised patients, most commonly as catheter-related bloodstream infections. However, Roseomonas infections are rarely reported in immunocompetent hosts. We report what we believe to be the first case in Korea of infectious spondylitis with bacteremia due to Roseomonas mucosa in an immunocompetent patient who had undergone vertebroplasty for compression fractures of his thoracic and lumbar spine.

Effect of Isolation Policy Using Cohorting Rooms on Isolation Rate of Multidrug-resistant Organisms and Antimicrobial Use Density: Focusing on Methicillin-Resistant Staphylococcus aureus and Multidrug-resistant Acinetobacter baumannii / 병원감염관리

BACKGROUND: We evaluated the effectiveness of isolation measures using cohorting rooms and antimicrobial use in reducing the isolation rate of methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant Acinetobacter baumannii (MDR-AB). METHODS: Four cohorting rooms (16 beds) for patients colonized or infected with multidrug-resistant organisms (MDRO) have been created in the general wards of our 894-bed hospital since October 2003. We prospectively evaluated the isolation rates of MRSA and MDR-AB, and amount of antimicrobial use during the 8-year study period. We also investigated the relationship between antimicrobial use density (AUD) and the isolation rates of MRSA and MDR-AB. RESULTS: After creating cohorting rooms, the isolation rates of MRSA decreased from 1.56 cases per 1,000 patient-days from 2004-2005 to 1.24 from 2006-2007 (P=0.57). The isolation rates of MDR-AB also decreased from 0.72 from 2004-2005 to 0.36 from 2010-2011 (P<0.01). The mean quarterly AUDs of glycopeptides and carbapenems were 30.17+/-6.80 and 19.5+/-7.10, respectively. There were no significant correlations between AUD values and the isolation rate of MRSA or MDR-AB. CONCLUSION: This study suggests that isolation measures using cohorting rooms to help limit the transmission of MDRO infection and colonization, especially MDR-AB, in resource-limited settings is feasible and efficacious.

Prevalence of Latent Tuberculosis Infection among Health Care Workers in South Korea: A Multicenter Study / 결핵및호흡기질환

BACKGROUND: We investigated the prevalence of latent tuberculosis infection (LTBI) among the health care workers (HCWs) and analyzed its risk factors in South Korea. METHODS: A standard questionnaire regarding the baseline demographics and risk factors for LTBI was given to each participant and tuberculin skin test (TST), QuantiFERON-TB GOLD In-Tube (QFT-GIT) assay, and chest radiography were performed. RESULTS: A total of 493 participants, 152 (30.8%) doctors and 341 (69.2%) nurses were enrolled in eight tertiary referral hospitals. The mean age of the subjects was 30.6 years old, and 383 (77.7%) were female. Of the 152 doctors, 63 (41.4%) and 36 (23.7%) were positive by TST and by QTF-GIT, respectively, and among the 341 nurses, 119 (34.9%) and 49 (14.4%) had positive TST and QFT-GIT results, respectively. Overall, the agreement between the two tests was 0.22 by the chance corrected proportional agreement rate (kappa coefficient) in 493 subjects. Experience of working in tuberculosis (TB)-related departments was significantly associated with positive LTBI test results by QFT-GIT assay, not by TST. In multivariate analysis, only age was independently associated with increased risk of a positive TST result, while age and experience of working in TB-related departments (odds ratio, 2.29; 95% confidence interval, 1.01-5.12) were independently associated with increased risk of a positive QFT-GIT result. CONCLUSION: A high prevalence of LTBI was found among South Korean HCWs. Considering the association between the experience of working in TB-related departments and high risk of LTBI, QFT-GIT may be a better diagnostic test for LTBI than TST in HCWs.

Factors Associated with Infective Endocarditis and Predictors of 3-month mortality of Patients with Viridans Streptococcal Bacteremia

BACKGROUND: Viridans streptococci is a major pathogen of infective endocarditis. This study was conducted in order to investigate the factors associated with infective endocarditis and predictors for three-month mortality among patients with viridans streptococcal bacteremia (VSB). MATERIALS AND METHODS: In this study, among 261 eligible patients diagnosed as VSB from January 2000 through June 2011 in a university-affiliated hospital, a retrospective analysis of 197 patients was conducted. All patients with VSB were classified into two groups according to sites of bacteremia; infective endocarditis and other infections. Demographic and clinical characteristics were reviewed through electronic medical records factors associated with infective endocarditis and predictors of three-month mortality in VSB patients were evaluated. RESULTS: Of the 197 patients, 37 (18.8%) patients had viridans streptococcal infective endocarditis (VSIE) and 160 (81.2%) patients had VSB due to other infection. In logistic regression analysis, underlying valvular heart disease (odds ratio [OR], 48.43; 95% confidence interval [CI], 5.77-406.38) and persistent bacteremia (OR, 46.32; 95% CI, 7.18-299.01) showed an independent association with VSIE. Three-month mortality rate was 21.7% in patients with VSB. In logistic regression analysis, previous steroid use (OR, 9.31; 95% CI, 1.34-64.52), previous immunosuppressive therapy (OR, 9.50; 95% CI, 2.13-42.30), hypotension at onset of bacteremia (OR, 7.72, 95% CI, 2.45-24.33), and Charlson comorbidity score > or =3 (OR, 4.53, 95% CI, 1.55-13.28) showed an independent association with three-month mortality in patients with VSB. CONCLUSIONS: VSB patients who have valvular heart disease or persistent bacteremia routinely require echocardiography. Previous steroid use, immunosuppressive therapy, hypotension, and higher Charlson comorbidity score suggested poor prognosis in patients with VSB.

A Case of Bacillus licheniformis Spondylitis and Bacteremia in a Patient with Lung Cancer

Bacillus licheniformis is an aerobic, gram-positive, spore-forming rod bacteria usually found in the environment. Infections with B. licheniformis are rare and usually associated with an immunocompromised state, trauma, and an indwelling catheter. We report a case of bacteremic B. licheniformis spondylitis following vertebroplasty in a patient with lung cancer.

Serial Testing of T-SPOT.TB Assays with Anti-Tuberculosis Therapy in Patients with Extrapulmonay Tuberculosis

BACKGROUND: Limited data are available for the clinical utility of serial interferon-gamma producing T-cell response after initiation of treatment in patients with extrapulmonary tuberculosis (TB). We studied the serial TB-specific antigen T-cell responses measured using the T-SPOT.TB assay during the course of therapy. MATERIALS AND METHODS: We prospectively enrolled adult patients who were newly diagnosed with active extrapulmonary TB over a 24-month period. All patients were given standard anti-TB treatment. Blood samples were obtained for T-SPOT.TB at diagnosis, as well as 1-, 3-, 6-, and 12-months after initiating anti-TB therapy. RESULTS: A total of 52 patients with extrapulmonary TB (38 confirmed and 14 probable TB) were included in the final analysis. All patients had clinical and radiologic improvement after treatment and cured. T-SPOT.TB was positive for 90% at diagnosis, 100% at 1-, 3-, and 6-months, and 93% at 12-months after initiation of anti-TB therapy. There was no significant difference in median T-cell response between early secreting antigenic target-6 (ESAT-6) and culture filtrate protein-10 (CFP-10) at all time points. Median T-cell response steadily increased up to 6 months and then decreased. CONCLUSIONS: T-SPOT.TB assay remained positive after successful anti-TB treatment in most patients with extrapulmonary TB. Our data suggests that serial T-SPOT.TB has limited clinical utility as a surrogate marker of treatment response in patients with extrapulmonary TB.

Drug-Resistant Extrapulmonary Tuberculosis

The prevalence and pattern of drug-resistant extrapulmonary tuberculosis (TB) is not well characterized in Korea. Therefore, we assessed the incidence of drug resistance for extrapulmonary TB in adult patients at a tertiary hospital. We retrospectively reviewed the medical records and results of drug susceptibility test in all culture-confirmed extapulmonary TB patients during an 18-month period. Out of a total of 168 cases in which the drug susceptibility test was performed, resistance to at least one anti-TB drug was found in 15 cases (8.9%), and multidrug resistance, in which TB was resistant to at least isoniazid and rifampin, was found in 3 cases (1.8%)

A Case of Coinfection with Pandemic (H1N1) 2009 Influenza and Scrub Typhus with Abnormal Liver Function Test / 결핵및호흡기질환

The pandemic (H1N1) 2009 influenza outbreak coincided with the typical Scrub typhus season, which can lead to diagnostic difficulties due to their similar and non-specific symptoms. Here we describe a case of laboratory confirmed co-infection of Pandemic (H1N1) 2009 influenza and Scrub typhus and discuss the difficulties in distinguishing the two illnesses clinically.

A case of acute Q fever with fibrin-ring granuloma in the bone marrow and lymph node biopsy / 대한내과학회지

Q fever is a zoonotic infection caused by Coxiella burnetii. Acute Q fever usually develops as a self-limited flu-like illness, atypical pneumonia, or hepatitis. We experienced a case of Q fever in a 50-year-old male who had a prolonged fever. The bone marrow and lymph node biopsy revealed fibrin-ring granulomas, which is a distinct finding of Q fever. The diagnosis was proven by high titers of C. burnetii anti-phase II antibody (IgM 1:512 and IgG >,048) and positive nested PCR for the com-1 gene. Q fever is rare in Korea, but should be considered in the differential diagnosis of fever of unknown origin