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Background@#Since the emergence of hypervirulent strains of Clostridioides difficile, the incidence of C. difficile infections (CDI) has increased significantly. @*Methods@#To assess the incidence of CDI in Korea, we conducted a prospective multicentre observational study from October 2020 to October 2021. Additionally, we calculated the incidence of CDI from mass data obtained from the Health Insurance Review and Assessment Service (HIRA) from 2008 to 2020. @*Results@#In the prospective study with active surveillance, 30,212 patients had diarrhoea and 907 patients were diagnosed with CDI over 1,288,571 patient-days and 193,264 admissions in 18 participating hospitals during 3 months of study period; the CDI per 10,000 patientdays was 7.04 and the CDI per 1,000 admission was 4.69. The incidence of CDI was higher in general hospitals than in tertiary hospitals: 6.38 per 10,000 patient-days (range: 3.25–12.05) and 4.18 per 1,000 admissions (range: 1.92–8.59) in 11 tertiary hospitals, vs. 9.45 per 10,000 patient-days (range: 5.68–13.90) and 6.73 per 1,000 admissions (range: 3.18–15.85) in seven general hospitals. With regard to HIRA data, the incidence of CDI in all hospitals has been increasing over the 13-year-period: from 0.3 to 1.8 per 10,000 patient-days, 0.3 to 1.6 per 1,000 admissions, and 6.9 to 56.9 per 100,000 population, respectively. @*Conclusion@#The incidence of CDI in Korea has been gradually increasing, and its recent value is as high as that in the United State and Europe. CDI is underestimated, particularly in general hospitals in Korea.
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Background@#A healthcare system’s collapse due to a pandemic, such as the coronavirus disease 2019 (COVID-19), can expose healthcare workers (HCWs) to various mental health problems. This study aimed to investigate the impact of the COVID-19 pandemic on the depression and anxiety of HCWs. @*Methods@#A nationwide questionnaire-based survey was conducted on HCWs who worked in healthcare facilities and public health centers in Korea in December 2020. Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder-7 (GAD-7) were used to measure depression and anxiety. To investigate factors associated with depression and anxiety, stepwise multiple logistic regression analysis was performed. @*Results@#A total of 1,425 participating HCWs were included. The mean depression score (PHQ-9) of HCWs before and after COVID-19 increased from 2.37 to 5.39, and the mean anxiety score (GAD-7) increased from 1.41 to 3.41. The proportion of HCWs with moderate to severe depression (PHQ-9 ≥ 10) increased from 3.8% before COVID-19 to 19.5% after COVID-19, whereas that of HCWs with moderate to severe anxiety (GAD-7 ≥ 10) increased from 2.0% to 10.1%. In our study, insomnia, chronic fatigue symptoms and physical symptoms after COVID-19, anxiety score (GAD-7) after COVID-19, living alone, and exhaustion were positively correlated with depression. Furthermore, post-traumatic stress symptoms, stress score (Global Assessment of Recent Stress), depression score (PHQ-9) after COVID-19, and exhaustion were positively correlated with anxiety. @*Conclusion@#In Korea, during the COVID-19 pandemic, HCWs commonly suffered from mental health problems, including depression and anxiety. Regularly checking the physical and mental health problems of HCWs during the COVID-19 pandemic is crucial, and social support and strategy are needed to reduce the heavy workload and psychological distress of HCWs.
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Background@#People living with human immunodeficiency virus (PLHIV) have an increased risk of atherosclerosis and cardiovascular disease, but specific guidance on when to suspect the onset of these diseases is limited. @*Materials and Methods@#We aimed to identify cardiovascular risk factors in PLHIV using carotid intima-media thickness (IMT) through a cross-sectional, retrospective cohort study that enrolled 217 PLHIV who underwent carotid IMT measurement at a teaching hospital in Korea. We compared clinical characteristics between PLHIV with subclinical atherosclerosis and PLHIV with IMT within the normal range, and used a receiver operating characteristic curve to determine the cut-off age for predicting subclinical atherosclerosis. @*Results@#Among the study population, 115 participants (53.0%) had subclinical atherosclerosis. In logistic regression, age and dyslipidemia were significantly associated with increased carotid IMT even after adjusting for other variables (odds ratio [OR]: 1.11, 95% confidence interval [CI]: 1.06 - 1.15, P <0.001; OR: 3.92, 95% CI: 1.87 - 8.22, P <0.001, respectively). The cut-off age for predicting subclinical atherosclerosis was 39.5 years (area under the curve 0.78, 95% CI: 0.72 - 0.84, P <0.001). @*Conclusion@#Conventional risk factors including age and dyslipidemia were associated with subclinical atherosclerosis in Asian PLHIV. In particular, Asian PLHIV older than 40 years had an increased risk of subclinical atherosclerosis and may benefit from carotid IMT screening.
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Identifying inappropriately prescribed antibiotics for infectious diseases by monitoring the quality of antibiotics use is essential for effective implementation of antibiotic stewardship. Qualitative assessment of the use of antibiotics has been conducted in some countries, including Korea, since the 2000s. The qualitative assessment generally involves an assessment of each component of the antibiotics prescription process, based on specific criteria. However, there is no standardized assessment method or cycle, and infectious diseases or antibiotics included in the assessments vary from country-to-country.According to the results reported in the United States, Europe, Australia, and Korea so far, approximately 20 - 55% of all antibiotics prescriptions are inappropriate. In this review, we describe the current progress in the quality assessment of the use of antibiotics on a global scale. Further, we highlight the future directions to improve antibiotic stewardship activities and the quality assessment of the use of antibiotics in Korea.
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Background@#The coronavirus disease 2019 (COVID-19) pandemic has caused health problems and distress among healthcare workers (HCWs), so supportive measures to promote their health and relieve distress are needed. @*Materials and Methods@#We conducted two rounds of Delphi surveys with 20 COVID-19-related frontline healthcare professionals and public officials. The surveys evaluated means of supporting HCWs’ health by improving health care systems and working environments in terms of effectiveness and urgency. The validity of the measures was assessed by calculating the content validity ratio. @*Results@#The top-priority measures to support HCWs were “secure isolation units capable of treating severe cases” in the facility infrastructure category, “secure nursing staff dedicated for patients in the intensive care units” in the personnel infrastructure category, “improve communication between central office and frontline field” in the cooperation system category, “support personal protective equipment and infection control supplies” in the aid supplies category, and “realization of hazard pay” in the physical/mental health and compensation category. @*Conclusion@#There was consensus among the experts on the validity and priorities of policies in the facility, personnel, cooperation, supplies, and compensation categories regarding measures to promote COVID-19 related HCWs’ health.
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Background@#It is necessary to develop a roadmap for antimicrobial usage monitoring in order to perform monitoring of antimicrobial use at the national level properly. Therefore, this study aimed to develop a roadmap for establishing surveillance and monitoring of antimicrobial use in medical institutions at the national level. @*Materials and Methods@#A modified Delphi study was conducted, including 3 rounds of an online survey and a virtual meeting with 16 expert panels. The survey items were developed based on a literature review of the surveillance systems for antimicrobial use in 12 countries and interviews with experts. The questionnaire was designed to include both the surveillance and benchmarking systems. @*Results@#Regarding the scope of target institutions to be included in the surveillance system, medical institutions for sentinel surveillance had the highest proportion of agreement among the panels (75.0%, 9/12). For the benchmarking system, “tertiary- and secondarycare hospitals” were accepted as the scope of target institutions at the current moment.Furthermore, the National Health Insurance claims and prescription data of individual hospitals were considered appropriate data sources for the surveillance system. As for the measures to promote the participation of hospitals in the benchmarking system, “compensation through the establishment of antimicrobial management fees” and “set the participation in the program as a quality evaluation or accreditation index for hospital evaluation” were accepted. @*Conclusion@#This study provides a roadmap for establishing an antimicrobial use monitoring and benchmarking system for medical institutions at a national level in Korea.
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Background@#As the coronavirus disease 2019 (COVID-19) pandemic is ongoing, heavy workload of healthcare workers (HCWs) is a concern. This study investigated the workload of HCWs responding to the COVID-19 outbreak in South Korea. @*Methods@#A nationwide cross-sectional survey was conducted from September 16 to October 15, 2020, involving 16 healthcare facilities (4 public medical centers, 12 tertiary-care hospitals) that provide treatment for COVID-19 patients. @*Results@#Public medical centers provided the majority (69.4%) of total hospital beds for COVID-19 patients (n = 611), on the other hand, tertiary care hospitals provided the majority (78.9%) of critical care beds (n = 57). The number of beds per doctor (median [IQR]) in public medical centers was higher than in tertiary care hospitals (20.2 [13.0, 29.4] versus 3.0 [1.3, 6.6], P = 0.006). Infectious Diseases physicians are mostly (80%) involved among attending physicians. The number of nurses per patient (median [interquartile range, IQR]) in tertiarycare hospitals was higher than in public medical centers (4.6 [3.4–5] vs. 1.1 [0.8–2.1], P =0.089). The median number of nurses per patient for COVID-19 patients was higher than the highest national standard in South Korea (3.8 vs. 2 for critical care). All participating healthcare facilities were also operating screening centers, for which a median of 2 doctors, 5 nurses, and 2 administrating staff were necessary. @*Conclusion@#As the severity of COVID-19 patients increases, the number of HCWs required increases. Because the workload of HCWs responding to the COVID-19 outbreak is much greater than other situations, a workforce management plan regarding this perspective is required to prevent burnout of HCWs.
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The study aimed to elucidate simple and effective risk factors for scabies infection in the medical environment for early detection and prevention of exposure to other patients and medical staff. We conducted a case-control study of patients who were diagnosed with scabies among hospitalized patients between 2008 and 2019 in an acute-care teaching hospital. Each case was matched according to sex and age with two randomly selected controls without scabies during hospitalization. Clinical characteristics of cases at the time of hospital admission were compared to those of the control group. The scabies group included 34 patients and 68 patients who were included in the control group. After adjusting for confounding factors, previous long-term care facility admission was only associated with scabies (adjusted odds ratio, 5.44; 95% confidence interval, 1.46–20.27; P = 0.012). Careful examination, particularly for patients with previous long-term care facility admission, might be useful for the early detection of scabies.
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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.
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Background@#Tuberculous meningitis (TBM) is the most severe form of tuberculosis, but differentiating between the diagnosis of TBM and viral meningitis (VM) is difficult. Thus, we have developed machine-learning modules for differentiating TBM from VM.Material and Methods: For the training data, confirmed or probable TBM and confirmed VM cases were retrospectively collected from five teaching hospitals in Korea between January 2000 - July 2018. Various machine-learning algorithms were used for training. The machinelearning algorithms were tested by the leave-one-out cross-validation. Four residents and two infectious disease specialists were tested using the summarized medical information. @*Results@#The training study comprised data from 60 patients with confirmed or probable TBM and 143 patients with confirmed VM. Older age, longer symptom duration before the visit, lower serum sodium, lower cerebrospinal fluid (CSF) glucose, higher CSF protein, and CSF adenosine deaminase were found in the TBM patients. Among the various machinelearning algorithms, the area under the curve (AUC) of the receiver operating characteristics of artificial neural network (ANN) with ImperativeImputer for matrix completion (0.85; 95% confidence interval 0.79 - 0.89) was found to be the highest. The AUC of the ANN model was statistically higher than those of all the residents (range 0.67 - 0.72, P <0.001) and an infectious disease specialist (AUC 0.76; P = 0.03). @*Conclusion@#The machine-learning techniques may play a role in differentiating between TBM and VM. Specifically, the ANN model seems to have better diagnostic performance than the non-expert clinician.
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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.
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Background@#Tuberculous meningitis (TBM) is the most severe form of tuberculosis, but differentiating between the diagnosis of TBM and viral meningitis (VM) is difficult. Thus, we have developed machine-learning modules for differentiating TBM from VM.Material and Methods: For the training data, confirmed or probable TBM and confirmed VM cases were retrospectively collected from five teaching hospitals in Korea between January 2000 - July 2018. Various machine-learning algorithms were used for training. The machinelearning algorithms were tested by the leave-one-out cross-validation. Four residents and two infectious disease specialists were tested using the summarized medical information. @*Results@#The training study comprised data from 60 patients with confirmed or probable TBM and 143 patients with confirmed VM. Older age, longer symptom duration before the visit, lower serum sodium, lower cerebrospinal fluid (CSF) glucose, higher CSF protein, and CSF adenosine deaminase were found in the TBM patients. Among the various machinelearning algorithms, the area under the curve (AUC) of the receiver operating characteristics of artificial neural network (ANN) with ImperativeImputer for matrix completion (0.85; 95% confidence interval 0.79 - 0.89) was found to be the highest. The AUC of the ANN model was statistically higher than those of all the residents (range 0.67 - 0.72, P <0.001) and an infectious disease specialist (AUC 0.76; P = 0.03). @*Conclusion@#The machine-learning techniques may play a role in differentiating between TBM and VM. Specifically, the ANN model seems to have better diagnostic performance than the non-expert clinician.
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During the 2019 domestic measles outbreak in Korea, measles occurred in healthcare workers with two doses of the measles, mumps and rubella vaccine, and the strict application of the Occupational Safety and Health Act required medical institutions to identify healthcare workers' immunity to measles and vaccinate the susceptible pockets. In response to the frontline medical institutions' request to review the measles recommendations and guidelines, the Korean Society of Infectious Diseases held a roundtable discussion on the causes of measles outbreak, timing of vaccinations, antibody tests, and booster vaccinations for healthcare workers, and financial support from the government and municipality as well as response strategies against the outbreak in healthcare settings. In Korea, the seroprevalence of measles is decreasing in the vaccine-induced immunity group during the maintenance of measles elimination over several years. The susceptible group against measles is in their 20s and 30s, and this may be because of waning immunity rather than nonresponse considering Korea's vaccine policy. The risk of measles nosocomial infection from community increases as these susceptible pockets actively engage in medical institutions.Thus, data on the immunity of low seroprevalence group in Korea are needed, further discussion is needed on the booster vaccination based on the data. Especially, antibody testing and vaccination in healthcare workers may be necessary to prevent the spread of measles in medical insutitutions, and further discussion is needed regarding specific testing methods, and the timing and frequency of test and vaccination.
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During the 2019 domestic measles outbreak in Korea, measles occurred in healthcare workers with two doses of the measles, mumps and rubella vaccine, and the strict application of the Occupational Safety and Health Act required medical institutions to identify healthcare workers' immunity to measles and vaccinate the susceptible pockets. In response to the frontline medical institutions' request to review the measles recommendations and guidelines, the Korean Society of Infectious Diseases held a roundtable discussion on the causes of measles outbreak, timing of vaccinations, antibody tests, and booster vaccinations for healthcare workers, and financial support from the government and municipality as well as response strategies against the outbreak in healthcare settings. In Korea, the seroprevalence of measles is decreasing in the vaccine-induced immunity group during the maintenance of measles elimination over several years. The susceptible group against measles is in their 20s and 30s, and this may be because of waning immunity rather than nonresponse considering Korea's vaccine policy. The risk of measles nosocomial infection from community increases as these susceptible pockets actively engage in medical institutions.Thus, data on the immunity of low seroprevalence group in Korea are needed, further discussion is needed on the booster vaccination based on the data. Especially, antibody testing and vaccination in healthcare workers may be necessary to prevent the spread of measles in medical insutitutions, and further discussion is needed regarding specific testing methods, and the timing and frequency of test and vaccination.
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There are limited data on the duration of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in respiratory specimens after resolution of coronavirus disease 2019 (COVID-19)-associated symptoms/signs. We determined duration of SARS-CoV-2 virus shedding in symptomatic patients after remission of symptoms. We investigated the duration of SARS-CoV-2 RNA detection using real-time reverse transcriptase polymerase chain reaction for SARS-CoV-2 in nasopharyngeal/oropharyngeal swabs or sputum or saliva. Six patients were included in the final analysis. The median (range) duration of SARS-CoV-2 viral detection after hospitalization was 34 days (22 to 67). After resolution of symptoms/signs, SARS-CoV-2 RNA was detected for median (range) of 26 days (9 to 48). Among the six patients, one had persistent detection of SARS-CoV-2 RNA until day 67 of hospitalization, which was 30 days after symptom resolution. This case represents the longest duration of SARS-CoV-2 detection, and highlights the need for long-term follow up of COVID-19 patients despite resolution of symptoms to confirm SARS-CoV-2 clearance.
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Background/Aims@#This study aimed to collect information on the opinions of Korean infectious disease (ID) experts on coronavirus disease 2019 (COVID-19) and related issues in preparation for a future outbreak. @*Methods@#A survey was conducted over the course of 5 days (from April 21 to 25, 2020), targeting all adult ID specialists currently in the medical field in South Korea (n = 265). An online-based survey was forwarded via text message and e-mail. Only one response was accepted from each participant. @*Results@#Of these 265 ID specialists gotten to, 132 (49.8%) responded. The highest proportion of the respondents envisaged the current COVID-19 outbreak to end after December 2020 (47.7% for the domestic Korean outbreak and 70.5% for the global pandemic); moreover, 60.7% of them stated that a second nationwide wave is likely to occur between September and December 2020 in South Korea. N95 respirators were considered to be the most important item in hospitals in preparation for a second wave. The most important policy to be implemented at the national level was securing national hospitals designated for the treatment of ID (67.4%). @*Conclusions@#ID experts in South Korea believe that the COVID-19 pandemic may not be easily controlled and that a second nationwide wave is likely to occur in South Korea. Our results indicate that Korean ID specialists believe that a high level of preparation is needed in various aspects, including the procurement of personal protective equipment, to respond efficiently to a second outbreak.
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This study aimed to evaluate the infectious disease (ID) physician workforce in Korea. We investigated the acquisition of ID physicians from 1992 to 2019 with their current working place in the Health Care System. We defined ID physicians working at general or tertiarycare hospitals as active ID physicians. A total 275 physicians acquired ID as a sub-specialty.Among the 275, 242 were active ID physicians. The density of active ID physicians was 0.47 per 100,000 population. Of all the 17 administrative districts, 11 (64.7%) fell short of 0.47, and 131 medical institutions employed the service of ID physicians. The median number of beds per adult ID physician was 372 (interquartile range, 280–507). It is essential to secure human resources to respond to emerging infectious diseases and perform the inherent work of ID physicians.
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This study aimed to evaluate the infectious disease (ID) physician workforce in Korea. We investigated the acquisition of ID physicians from 1992 to 2019 with their current working place in the Health Care System. We defined ID physicians working at general or tertiarycare hospitals as active ID physicians. A total 275 physicians acquired ID as a sub-specialty.Among the 275, 242 were active ID physicians. The density of active ID physicians was 0.47 per 100,000 population. Of all the 17 administrative districts, 11 (64.7%) fell short of 0.47, and 131 medical institutions employed the service of ID physicians. The median number of beds per adult ID physician was 372 (interquartile range, 280–507). It is essential to secure human resources to respond to emerging infectious diseases and perform the inherent work of ID physicians.
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BACKGROUND@#Healthcare workers (HCWs) have a high risk of tuberculosis (TB) infection. Since August 2017, Korea has mandated the testing of latent TB infection (LTBI) and recommended treatment from HCWs at medical institutions. However, the acceptance/completion rate and adverse events of LTBI treatment have not been analyzed.@*MATERIALS AND METHODS@#From February to August 2017, we conducted a retrospective study at a referral university hospital in Korea, to screen the interferon-gamma release assay (IGRA) tests conducted for all HCWs for detecting and treating LTBI. HCWs diagnosed with LTBI were offered a 9-month isoniazid (9H), 3-month isoniazid/rifampin (3HR), or 4-month rifampin regimen. We investigated the acceptance/completion rate, adverse events, and causes of discontinuation or change in LTBI medication. A major adverse event was one wherein a patient had any adverse event ≥grade 3 causing LTBI treatment interruption.@*RESULTS@#Of the 1,538 HCWs, 1,379 underwent IGRA testing for LTBI. Among them, 13.6% (187/1,379) tested positive and 73.3% (137/187) received treatment. The overall completion rate was 97.8% (134/137). HCWs were significantly more likely to complete first-line therapy with 3HR than with 9H (91.4% vs. 76.7%, P = 0.02). The most common major adverse event was hepatotoxicity (n = 7), followed by thrombocytopenia (n = 1) and anaphylactic shock (n = 1). Hepatotoxicity and hepatotoxicity (≥ grade 2) were more frequent in 9H than in 3HR (39.5% vs. 17.2%, P = 0.006 and 18.6% vs. 3.7%, P = 0.005, respectively). The median time to hepatotoxicity was 96 days (interquartile range, 20 – 103 days).@*CONCLUSION@#Completion of first-line therapy for LTBI is more likely with 3HR than with 9H. This might be related to the development of hepatotoxicity after around 3 months of treatment. Anaphylactic shock and platelet count should be carefully monitored in those receiving rifampin-containing regimens.
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BACKGROUND: In-hospital detection of newly diagnosed active pulmonary tuberculosis (TB) is important for prevention of potential outbreaks. Here, we report our experience of the aggressive contact investigation strategy in a university hospital in the Republic of Korea after healthcare workers (HCWs), patients, and visitors experience an in-hospital exposure to active pulmonary TB. METHODS: A contact investigation after the unexpected detection of newly diagnosed active pulmonary TB (index patients) was performed in a university hospital from August 2016 to April 2017. Initial and 3-month-post-exposure chest radiographs were advised for all patients, visitors, and HCWs in close contact with the index patients. An additional tuberculous skin test or interferon gamma releasing assay was performed at the time of exposure and 3 months post-exposure in HCWs in close contact with the index patients. RESULTS: Twenty-four index patients were unexpectedly diagnosed with active pulmonary TB after admission to the hospital with unassociated diseases. The median time from admission to TB diagnosis was 5 days (range, 1–22 days). In total, 1,057 people were investigated because of contact with the index patients, 528 of which had close contact (206 events in 157 HCWs, 322 patients or visitors). Three months post exposure, 9 (9.2%) among 98 TB-naïve close contact HCWs developed latent tuberculosis infections (LTBIs). Among the 65 close contact patients or visitors, there was no radiological or clinical evidence of active pulmonary TB. CONCLUSION: An aggressive contact investigation after an unexpected in-hospital diagnosis of active pulmonary TB revealed a high incidence of LTBI among TB-naïve HCWs who had contact with the index patients.