Widespread Household Transmission of SARS-CoV-2 B.1.1.529 (Omicron) Variant from Children, South Korea, 2022

The role that children play in the transmission of the omicron variant is unclear. Here we report an outbreak that started in young children attending various pediatric facilities, leading to extensive household transmission that affected 75 families with 88 confirmed case-patients in 3 weeks. Tailored social and public health measures directed towards children and pediatric facilities are warranted with the emergence of highly transmissible omicron variant to mitigate the impact of coronavirus diseases 2019 (COVID-19).

A low risk of nosocomial transmission of subclinical tuberculosis to neonates in a postpartum care center under COVID-19 control measures

We report the results of investigating and managing a tuberculosis (TB) exposure in a postpartum care center. Among the contacts exposed to a nursing assistant with subclinical TB, 5 of 44 neonates (11.4%) had positive tuberculin skin tests (TSTs) at 3 months of age, and all the TST-positive neonates received the Bacille Calmette-Guérin vaccination. Seven of 28 healthcare workers (25.0%) and 1 of 3 household contacts (33.3%) were positive in the initial or repeated interferon-gamma release assay. None of the contacts developed TB disease during the study period. Annual TB examinations of healthcare personnel at a postpartum care center under the Tuberculosis Prevention Act in South Korea enabled the early detection of subclinical TB, which reduced the risk of transmission to neonates under strict coronavirus disease 2019 prevention measures.

Importation and Transmission of SARS-CoV-2 B.1.1.529 (Omicron) Variant of Concern in Korea, November 2021

In November 2021, 14 international travel-related severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) B.1.1.529 (omicron) variant of concern (VOC) patients were detected in South Korea. Epidemiologic investigation revealed community transmission of the omicron VOC. A total of 80 SARS-CoV-2 omicron VOC-positive patients were identified until December 10, 2021 and 66 of them reported no relation to the international travel.There may be more transmissions with this VOC in Korea than reported.

Serotype Distribution and Antimicrobial Susceptibilities of Invasive Streptococcus pneumoniae Isolates from Adults in Korea from 1997 to 2012

In Republic of Korea, a 7-valent pneumococcal conjugated vaccine (PCV7) was licensed for use in infants in 2003, and 13-valent PCV (PCV13) replaced it since 2010. We investigated trends in serotype distribution and antibiotic susceptibility of pneumococcal isolates from adult patients with invasive pneumococcal diseases (IPD). Invasive pneumococcal isolates from adult patients of ≥ 16 years of age were collected from 1997 to 2012. Serotypes of the isolates were determined by the Quellung reaction. Distribution of serotypes was analyzed according to the vaccine types. Antibiotic susceptibility was tested by using E-test strips. A total of 272 invasive pneumococcal isolates were included. The most common serotypes were serotype 19F (8.5%, 23/272), and serotype 3 (8.1%, 22/272), and 24.6% (67/272) of the isolates were of non-vaccine serotypes. Of the 272 isolates, 2.6% (7/272) were penicillin MICs of ≥ 4 µg/mL. The proportion of the PCV13 serotypes decreased from 63.3% (50/79) in 1997-2003 to 48.6% (17/35) in 2011-2012, whereas that of non-vaccine serotypes was 26.6% (21/79) and 25.7% (9/35), respectively, for the same periods. The proportion of the PCV13 serotypes showed a decreasing trend among adult patients with IPD over the study period.

Multiple Opportunistic Infections and Primary Central Nervous System Lymphoma in a Patient with Idiopathic CD4+ T-lymphocytopenia

We describe a case of idiopathic CD4+ T-lymphocytopenia (ICL) in a 59-year-old patient who presented with various opportunistic infections. The patient was diagnosed with disseminated Mycobacterium avium infection, cytomegalovirus colitis and retinitis, and esophageal candidiasis. He was successfully treated with anti-mycobacterial drugs, ganciclovir, and fluconazole, respectively. However, the patient was diagnosed with primary central nervous system lymphoma, and then died of a Trichosporon beigelii sepsis during the 2nd cycle of systemic chemotherapy.

Incidence of Atazanavir-associated Hyperbilirubinemia in Korean HIV Patients: 30 Months Follow-up Results in a Population with Low UDP-glucuronosyltransferase1A1*28 Allele Frequency

Hyperbilirubinemia is frequently observed in Caucasian HIV patients treated with atazanavir. UDP-glucuronosyltransferase 1A1 polymorphism, UGT1A1*28, which is associated with atazanavir-induced hyperbilirubinemia, is less common in Asians than in Caucasians. However, little is known about the incidence of atazanavir-associated hyperbilirubinemia in Asian populations. Our objective was to investigate the incidence of and tolerability of atazanavir-associated hyperbilirubinemia in Korean HIV patients. The prevalence and cumulative incidence of atazanavir-associated hyperbilirubinemia and UGT1A1*28 allele frequency was investigated in 190 Korean HIV-infected patients treated with atazanavir 400 mg per day. The UGT1A1*28 were examined by direct sequencing of DNA from peripheral whole blood. The UGT1A1*28 allele frequency was 11%. The cumulative incidence of any grade of hyperbilirubinemia was 77%, 89%, 98%, and 100%, at 3, 12, 24, and 30 months, respectively. The cumulative incidence of severe (grade 3-4) hyperbilirubinemia was 21%, 41%, 66%, and 75%, at 3, 12, 24, and 30 months, respectively. However, the point prevalence of severe hyperbilirubinemia did not increase with time and remained around 25%. Our data suggest that atazanavir-associated hyperbilirubinemia is common but transient in a population with low UGT1A1*28 allele frequency.

Spectrum of Intracranial Parenchymal Lesions in Patients with Human Immunodeficiency Virus Infection in the Republic of Korea

The incidence of specific intracranial parenchymal lesions of HIV-infected patients varies considerably between countries. In the Republic of Korea, the number of HIV-infected patients is increasing, but little is known regarding the spectrum of intracranial parenchymal lesions in these patients. The aim of the present study was to obtain this information. To identify HIV patients with intracranial parenchymal lesions, the electronic database of radiological reports for 1,167 HIV-infected patients, seen from 1999 to 2008 at the Seoul National University Hospital, were reviewed. Neuroradiologic studies were performed on 165 of these patients, and intracranial parenchymal lesions were detected in 40 (3.4%) of them. Thirty-seven were male, and median age was 41 yr (range, 26-61). At the time of the diagnosis of intracranial parenchymal lesions, median CD4+ lymphocyte count was 40 cells/microL (range 5-560) and in 33 (82.5%) patients, it was less than 200 cells/microL. Progressive multifocal leukoencephalopathy (12 patients) is the most frequent intracranial parenchymal lesions, followed by intracranial tuberculoma (7 patients), primary central nervous system lymphoma (7 patients), intracranial cryptococcoma (4 patients), Toxoplasma encephalitis (4 patients), and disseminated non-tuberculous mycobacterial infection (3 patients).

Tuberculous Lymphadenitis in Patients with Myelogenous Leukemia

During the neutropenic phase, leukemia patients receiving chemotherapy are prone to bacterial and, fungal infections; occasionally mycobacterial, viral and protozoal organisms may also cause infections. Mycobacterium tuberculosis infection was reported very rarely in these patients. This report describes four patients with M. tuberculosis infection identified from 185 adult patients who were diagnosed myelogenous leukemia between January 2003, and December 2004. There was no patient with M. tuberculosis infection from 44 lymphoid leukemia and 11 acute biphenotypic leukemia patients. Sites of infection were all lymph nodes. Three among four patients were presented with lymphadenopathy at initial diagnosis of leukemia, and the other one presented with lymphadenopathy after induction chemotherapy. There was no patient presented with lymphadenopathy during the neutropenic phase. Tuberculous lymphadenitis was presented in a patient with three acute myelogenous leukemia (FAB class 2 M4, 1 M2) and a chronic myelogenous leukemia, accelerated phase. An acute myelogenous leukemia patient had a leukemic cell and tubercle bacilli in the same lymph node. Tuberculosis should also be included as a differential diagnosis in myelogenous leukemia patient with lymphadenopathy, especially in the countries in which the disease is endemic.

Multicenter Study for Frequency and Clinical Features of Community-Associated Methicillin-Resistant Staphylococcus aureus in Korea

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) infection has emerged in patients who do not have the established risk factors. In Korea, little is known about the epidemiology and clinical features of community-associated MRSA (CA-MRSA). MATERIAL AND METHODS: Clinical microbiology laboratory databases of 7 hospitals were reviewed to identify the patients from whom MRSA was isolated during the period of January to July 2005. Only one isolate per patient was enrolled. In order to identify the risk factors of MRSA acquisition, the medical records and the Health Insurance Review Agency databases were reviewed. CA-MRSA was defined as MRSA isolated from patient without established risk factors. We analyzed patient demographics, underlying medical conditions, characteristics of infection, and antimicrobial susceptibility profiles. RESULTS: Of total 3,251 S. aureus isolates, 1900 (58.4%) were MRSAs. Of the MRSA isolates, 114 (6.0%) were CA-MRSA. Of 114 CA-MRSA isolates, 22 (19.3%) were colonizers, 22 (19.3%) were pathogens, and the clinical significance of remaining 70 (61.4%) could not be determined. Median age of the 22 patients with CA-MRSA disease was 47 years. Nine patients had skin and soft tissue infections, 9 ear infections, 3 bacteremia, 1 septic arthritis. Seven patients had underlying medical disease. None died of the CA-MRSA infections. Of the 73 isolates of CA-MRSA, 47 (64.4%) were resistant to more than 3 classes of antibiotics besides beta-lactams. CONCLUSION: Although MRSA is highly prevalent among hospital-associated S. aureus infection, CA-MRSA infections are not common.

Malignancies in Patients with Human Immunodeficiency Virus Infection in South Korea

BACKGROUND: Since highly active antiretroviral therapy has lengthened the life span of individuals infected with human immunodeficiency virus (HIV), the importance of malignancy associated with HIV has been increased. The relative frequencies of malignancies in HIV infected patients may vary in different race and region. The aim of this study is to determine the prevalence and characteristics of malignancies in patients with HIV infection in South Korea. MATERIALS AND METHODS: To identify HIV patients with malignancy, we reviewed the electronic database of pathological reports for all HIV-infected patients seen from January 1986 to December 2005 at the Seoul National University Hospital. We retrospectively reviewed the medical records of them. RESULTS: Among 850 patients infected with HIV, 33 episodes of malignant diseases were diagnosed in 32 patients (3.76%). Thirty were males, and median age was 46 years (range 29-70). At the time of the diagnosis of malignancy, median CD4+ lymphocytes count was 100/uL (range 5-620) and in 27 (82%) patients, CD4+ lymphocytes count were less than 200/uL. For 13 patients (40%), malignancy was initial presentation of HIV infection. Excluding patients initially diagnosed as malignancy, median follow-up duration from the first visit to diagnosis of malignancy was 36 months (range 3-96). Non-Hodgkin's lymphoma was the most frequent malignancy (13 patients), followed by Kaposi's sarcoma (7), Hodgkin's disease (3), acute myeloid leukemia (1), and other solid cancer (9) including one case of anal cancer associated with human papillomavirus. Among 13 patients with non-Hodgkin's lymphoma, 4(31%) achieved the complete remission after chemotherapy and/or radiation therapy, and had been followed without evidence of recurrence. CONCLUSION: Malignancy was diagnosed in 3.76% of patients infected with HIV. Non-Hodgkin's lymphoma is the most prevalent malignancy in HIV patients in South Korea.

Tuberculous Lymphadenitis in Patients with Myelogenous Leukemia

During the neutropenic phase, leukemia patients receiving chemotherapy are prone to bacterial and, fungal infections; occasionally mycobacterial, viral and protozoal organisms may also cause infections. Mycobacterium tuberculosis infection was reported very rarely in these patients. This report describes four patients with M. tuberculosis infection identified from 185 adult patients who were diagnosed myelogenous leukemia between January 2003, and December 2004. There was no patient with M. tuberculosis infection from 44 lymphoid leukemia and 11 acute biphenotypic leukemia patients. Sites of infection were all lymph nodes. Three among four patients were presented with lymphadenopathy at initial diagnosis of leukemia, and the other one presented with lymphadenopathy after induction chemotherapy. There was no patient presented with lymphadenopathy during the neutropenic phase. Tuberculous lymphadenitis was presented in a patient with three acute myelogenous leukemia (FAB class 2 M4, 1 M2) and a chronic myelogenous leukemia, accelerated phase. An acute myelogenous leukemia patient had a leukemic cell and tubercle bacilli in the same lymph node. Tuberculosis should also be included as a differential diagnosis in myelogenous leukemia patient with lymphadenopathy, especially in the countries in which the disease is endemic.

Multicenter Study for Frequency and Clinical Features of Community-Associated Methicillin-Resistant Staphylococcus aureus in Korea

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) infection has emerged in patients who do not have the established risk factors. In Korea, little is known about the epidemiology and clinical features of community-associated MRSA (CA-MRSA). MATERIAL AND METHODS: Clinical microbiology laboratory databases of 7 hospitals were reviewed to identify the patients from whom MRSA was isolated during the period of January to July 2005. Only one isolate per patient was enrolled. In order to identify the risk factors of MRSA acquisition, the medical records and the Health Insurance Review Agency databases were reviewed. CA-MRSA was defined as MRSA isolated from patient without established risk factors. We analyzed patient demographics, underlying medical conditions, characteristics of infection, and antimicrobial susceptibility profiles. RESULTS: Of total 3,251 S. aureus isolates, 1900 (58.4%) were MRSAs. Of the MRSA isolates, 114 (6.0%) were CA-MRSA. Of 114 CA-MRSA isolates, 22 (19.3%) were colonizers, 22 (19.3%) were pathogens, and the clinical significance of remaining 70 (61.4%) could not be determined. Median age of the 22 patients with CA-MRSA disease was 47 years. Nine patients had skin and soft tissue infections, 9 ear infections, 3 bacteremia, 1 septic arthritis. Seven patients had underlying medical disease. None died of the CA-MRSA infections. Of the 73 isolates of CA-MRSA, 47 (64.4%) were resistant to more than 3 classes of antibiotics besides beta-lactams. CONCLUSION: Although MRSA is highly prevalent among hospital-associated S. aureus infection, CA-MRSA infections are not common.

Malignancies in Patients with Human Immunodeficiency Virus Infection in South Korea

BACKGROUND: Since highly active antiretroviral therapy has lengthened the life span of individuals infected with human immunodeficiency virus (HIV), the importance of malignancy associated with HIV has been increased. The relative frequencies of malignancies in HIV infected patients may vary in different race and region. The aim of this study is to determine the prevalence and characteristics of malignancies in patients with HIV infection in South Korea. MATERIALS AND METHODS: To identify HIV patients with malignancy, we reviewed the electronic database of pathological reports for all HIV-infected patients seen from January 1986 to December 2005 at the Seoul National University Hospital. We retrospectively reviewed the medical records of them. RESULTS: Among 850 patients infected with HIV, 33 episodes of malignant diseases were diagnosed in 32 patients (3.76%). Thirty were males, and median age was 46 years (range 29-70). At the time of the diagnosis of malignancy, median CD4+ lymphocytes count was 100/uL (range 5-620) and in 27 (82%) patients, CD4+ lymphocytes count were less than 200/uL. For 13 patients (40%), malignancy was initial presentation of HIV infection. Excluding patients initially diagnosed as malignancy, median follow-up duration from the first visit to diagnosis of malignancy was 36 months (range 3-96). Non-Hodgkin's lymphoma was the most frequent malignancy (13 patients), followed by Kaposi's sarcoma (7), Hodgkin's disease (3), acute myeloid leukemia (1), and other solid cancer (9) including one case of anal cancer associated with human papillomavirus. Among 13 patients with non-Hodgkin's lymphoma, 4(31%) achieved the complete remission after chemotherapy and/or radiation therapy, and had been followed without evidence of recurrence. CONCLUSION: Malignancy was diagnosed in 3.76% of patients infected with HIV. Non-Hodgkin's lymphoma is the most prevalent malignancy in HIV patients in South Korea.