• Pediatric Infection and Vaccine
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• v.13 no.1
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• pp.63-70
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• 2006

Purpose : We hypothesized that mannose binding lectin gene(MBL2), a key molecule of innate immunity, may contirbute to the development and the outcome of respiratory syncytial virus(RSV) disease in early childhood. This study was performed to investigate the genetic basis of polymorphisms and haplotypes of MBL2 for RSV disease severity in Korean children. Methods : Cases with severe RSV diseases are 99 children with severe RSV lower respiratory tract infections, who were admitted to the Seoul National University Children's Hospital through 1993~2000. The control subjects consisted of 224 anonymous healthy Korean blood donors. The frequency of promoter variant(-221, X/Y) and structural variant(codon 54) were compared between the case patient group and the control subject group. Results : The mean age of patients was 11.8 months; 49% were <6 months, 39% were 6-24 months and 12% were >24 months. In the cohort of cases of severe RSV diseases, the genotypic frequencies of structural variant in codon 54 were 61% for AA, 34% for AB, and 5% for BB. Those of the promoter X/Y variant were 85% for YY and 15% for XY. There were no significant differences in overall distribution of both structural and promoter variants between the cases and the control subjects. We did not observe statistical difference in the haplotypic frequencies of MBL2. Conclusion : Common variants of MBL2 gene most likely do not contribute to the risk for severe RSV diseases in Korean children. Further genetic association studies should be conducted in a larger propsectively recruited cohort of children with RSV infection.

• Pediatric Infection and Vaccine
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• v.14 no.2
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• pp.179-187
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• 2007

Purpose : Acute viral respiratory tract infection is the most common illness among children. Involved organisms are respiratory syncytial virus (RSV), influenza virus, adenovirus, parainfluenza virus, etc. The objective of the present study is to determine epidemiology of each viral infection in Busan, South Korea between January 2004 and December 2006. Methods : We retrospectively analyzed the results of clinical samples of throat and nasal swab collected from Busan city, South Korea between January 2004 and December 2006. We collected these samples from the children with acute respiratory illness. Viruses were detected by virus culture Results : The identified pathogens were influenza A in 131 cases (46.6 percent), RSV in 40 cases (14.2 percent), influenza B in 37 cases (13.2 percent), adenovirus in 23 cases (8.2 percent), enterovirus in 37 cases (13.2%) [coxsackie virus in 20 cases (7.1 percent), atypical enterovirus in 9 cases (3.2 percent), poliovirus in 4 cases (1.4 percent), echovirus in 4 cases (1.4 percent)], rhinovirus in 9 cases (3.2 percent), parainfluenza virus in 2 cases (0.7 percent), coronavirus and bocavirus in each 1 case (0.4 percent). Influenza A were detected every year, mostly in December through April and RSV in October through February. Adenovirus were detected through out the year. Bocavirus occurred in December, 2006. Conclusion : We analyzed epidemiologic characteristics of viruses to cause the respiratory disease that prevailed at Busan area for recent three years, and from now on, a further continuous study will be necessary.

• Pediatric Infection and Vaccine
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• v.5 no.2
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• pp.258-266
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• 1998

Purpose : Cases of adenoviral penumonia with rapidly progressive clinical course were experienced. We reviewed these patients in viewpoint of clinical manifestation and adenoviral serotypes. Methods : Culture and indirect immunofluorescence for respiratory viruses including respiratory syncytial virus, influenza virus, parainfluenza virus, adenovirus was done with nasopharyngeal aspirates from patients who admitted due to respiratory infections in Fatima Hospital, Masan from Nov. 1996 to Jul. 1997. Cultured adenovirus was serotyped by both neutralization and hemagglutination inhibition test. Medical records were reviewed for 5 patients with respiratory failure from adenovirus was isolated and serotyped. Results : The total number of examined patients was 460 patients. We isolated respiratory viruses in 143(30.9%) patients. Adenovirus was isolated from 66 out of 143(46.2%) patients. During Jan 1997 to May 1997, five patients with ages of 18 days to 11 months who were infected by adenovirus and had high fever with dyspnea and required assisted mechanical ventilation. One patients discharged against doctor's advice then died. Two of four patients had complications of disseminated intravascular coagulation; two had bronchiolitis obliterans. Two isolates were serotype 7, and one was serotype 5, and two were untyped. Conclusion : Severe pneumonia caused by serotype 7 continued to occur in 1997 following the epidemic in 1996, and severe pneumonia may also be caused by serotype 5 and other serotypes.

• Tuberculosis and Respiratory Diseases
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• v.58 no.4
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• pp.385-391
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• 2005

Background : The incidence of nontuberculous mycobacterium (NTM) infections in Korea is increasing. This retrospective study was performed to examine the recovery rate of NTM from respiratory specimens as well as the isolated NTM colony characteristics, and to assess the clinical significance of a NTM isolation. Methods : The results of the respiratory specimens requested for an acid-fast bacilli (AFB) examination during 2002 at Asan Medical Center, along with the patients clinical characteristics were analyzed. Results : A total 26,820 respiratory specimens were requested for the acid-fast bacilli (AFB) smear and culture during the study period. The proportion of M. tuberculosis and NTM isolation was 5.7% and 2.2%, respectively. Among the AFB smear and culture positive specimens, 12.2% were found to be NTM. The scotochromogen showing a low colony count < 20, which appeared to be contaminants, were isolated in 31.8% of the 584 NTM isolates. Excluding the low-colony scotochromogens, the M. avium-intracellulare complex was the most common NTM isolates (42.1%), and was also the most common causative organism for NTM pulmonary diseases. 8.4% (23/275) and 17.8% (49/275) of patients with NTM isolates met the American and British Thoracic Society diagnostic criteria for NTM pulmonary disease, respectively. Conclusion : In case of a positive AFB-smear or culture result, the possibility of NTM being a causative organism should always be considered, even in Korea, which has an intermediate incidence of tuberculosis.

• Clinical and Experimental Pediatrics
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• v.48 no.9
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• pp.976-985
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• 2005

Purpose : Although influenza is one of the most important causes of acute respiratory tract infections in children, effective antiviral therapies are not common and there are only a few clinical studies on treatment of influenza in children. We evaluated the efficacy of oseltamivir in the treatment of naturally aquired influenza in children during the first half of 2004 in Busan. Methods : From January 2004 to June 2004, throat swabs and nasal washes were performed and cultured for the isolation of influenza virus and tested by rapid antigen detection test(QuickVue influenza test) in children with suspected influenza infections. The children who responded positively to the QuickVue influenza test, we divided into two groups : an oseltamivir treatment group and a control group. We compared their clinical symptoms(including fever duration) and diagnosis. The medical records of patients with influenza virus infection were reviewed retrospectively. Results : A total of 621 individuals were suspected of influenza infection. Influenza viruses were isolated in 79(17.2 percent) out of 621 patients examined. QuickVue influenza tests were positive in 181 cases. The treatment group(83 individuals) received oseltamivir twice daily for 5 days, and the control group(99 individuals) were administered only symptom relief medicine. There was no differences between the two groups in clinical diagnosis and symptoms. Oseltamivir treatment reduced the fever duration and other respiratory symptoms. There were no adverse events associated with oseltamivir treatment. Conclusion : Our data suggest that oral oseltamivir treatment reduces the fever duration and other respiratory symptoms of acute influenza without side effects in children.

• Pediatric Infection and Vaccine
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• v.14 no.1
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• pp.91-96
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• 2007

Purpose : This study was performed to evaluate a new rapid diagnostic kit (BIOLINE $RSV^{TM}$; Standard Diagnostics Inc., Yongin, Korea), a lateral-flow immunoassay, in the detection of respiratory syncytial virus (RSV) from the nasopharyngeal aspirates (NPA) of children with lower respiratory tract infections (LRTIs) in comparison with other diagnostic methods. Methods : Three hundred and nineteen NPAs were selected from a large pool of NPAs that had been obtained from children with LRTIs. All specimens had already been tested for RSV by culture and immunofluorescent (IF) test, and had been kept frozen. Tests with BIOLINE $RSV^{TM}$ were performed at least twice. All who conducted the experiments or interpreted the test results were blinded to the results of both culture and IF tests. Results : One hundred seven (97.3%) of 110 specimens that were positive for RSV by both culture and IF test, 29 (87.9%) of 33 that were positive by IF test only, 20 (76.9%) of 26 that were positive by culture only, and 140 (93.3%) of 150 that were negative by both methods were negative for RSV by BIOLINE $RSV^{TM}$. By combining the above results, the following 5 diagnostic values of BIOLINE $RSV^{TM}$ were determined in comparison with viral culture or IF test; sensitivity, 92.3% (156/169, 95% confidence interval [CI], 87.1-97.5%); specificity, 93.3% (140/150, 95% CI, 88.4-98.2%); positive predictive value, 94.0% (156/166, 95% CI, 89.5-98.5%); negative predictive value, 91.5% (140/143, 95% CI, 86.0-97.0%); and agreement, 95.9% (306/319, 95% CI, 92.1-99.7%), respectively. Conclusion : This study revealed that BIOLINE $RSV^{TM}$ demonstrated good sensitivity and specificity for the detection of RSV antigen from NPAs of children with LRTIs. Because of simple methods and quick results, this test may be useful for the diagnosis of RSV infection during the epidemic periods.

• Clinical and Experimental Pediatrics
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• v.52 no.3
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• pp.330-338
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• 2009

Purpose : The causes of acute lower respiratory tract infection (ALRTI) are mostly attributable to viral infection, including respiratory syncytial virus (RSV), parainfluenza virus (PIV), influenza virus A/B (IFV A/B), or adenovirus (ADV). Several Korean studies reported human metapneumovirus (hMPV) as a common pathogen of ALRTI. However, studies on seasonal distribution and clinical differences relative to other viruses are insufficient, prompting us to perform this study. Methods : From November 2006 to October 2007, we tested nasopharyngeal aspiration specimens in children hospitalized with ALRTI with the multiplex reverse transcriptase-polymerase chain reaction to identify 6 kinds of common pathogen (hMPV, RSV, PIV, IFV A/B, and ADV). We analyzed positive rates and clinical features by respiratory chart review. Results : We detected 38 (8.4%) hMPV-positive cases out of 193 (41.8%) virus-positive specimens among 462 patients. HMPV infection prevailed from March to June with incidence peaking in April. HMPV-positive patients were aged 15 years (76.3%), and the ratio of boys to girls was 1.2:1. The median age was 27 months. HMPV primarily caused pneumonia (76.3 %) (P=0.018). Average hospitalization of HMPV-associated ALRTI patients was 5.8 days. In addition, they showed parahilar peribronchial infiltration (100%) on chest X-ray, normal white blood cell count (73.7%), and negative C-reactive protein (86.8 %) (P>0.05). All hMPV-positive patients recovered without complication. Conclusion : HMPV is a common pathogen of ALRTI in Korean children, especially in 1-5 year olds, from March to May. Immunocompetent children diagnosed with hMPV-associated ALRTI may have a good prognosis.

• Pediatric Infection and Vaccine
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• v.28 no.2
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• pp.101-109
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• 2021

Purpose: Common human coronaviruses (HCoVs) are relatively understudied due to the mild nature of HCoV infection. Given the lack of local epidemiology data on common HCoVs, we aimed to describe clinical and epidemiological characteristics of common HCoVs in children. Methods: Respiratory viral test results from 9,589 respiratory samples from Seoul National University Children's Hospital were analyzed from January 2015 to December 2019. Viral detection was done by the multiplex reverse transcription polymerase chain reaction. Demographics and clinical diagnosis were collected for previously healthy children tested positive for HCoVs. Results: Of the 9,589 samples tested, 1 or more respiratory viruses were detected from 5,017 (52.3%) samples and 463 (4.8%) samples were positive for HCoVs (OC43 2.8%, NL63 1.4%, 229E 0.7%). All 3 types co-circulated during winter months (November to February) with some variation by type. HCoV-OC43 was the most prevalent every winter season. HCoV-NL63 showed alternate peaks in late winter (January to March) and early winter (November to February). HCoV-229E had smaller peaks every other winter. Forty-one percent of HCoV-positive samples were co-detected with additional viruses; human rhinovirus 13.2%, respiratory syncytial virus 13.0%, influenza virus 4.3%. Common clinical diagnosis was upper respiratory tract infection (60.0%) followed by pneumonia (14.8%), croup (8.1%), and bronchiolitis (6.7%). Croup accounted for 17.0% of HCoV-NL63-positive children. Conclusions: This study described clinical and epidemiological characteristics of common HCoVs (OC43, NL63, 229E) in children. Continuing surveillance, perhaps by adding HKU1 in the diagnostic panel can further elucidate the spectrum of common HCoV infections in children.

• Tuberculosis and Respiratory Diseases
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• v.85 no.1
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• pp.37-46
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• 2022

Background: Although respiratory tract infection is one of the most important factors triggering acute exacerbation of chronic obstructive pulmonary disease (AE-COPD), limited data are available to suggest an epidemiologic pattern of microbiology in South Korea. Methods: A multicenter observational study was conducted between January 2015 and December 2018 across 28 hospitals in South Korea. Adult patients with moderate-to-severe acute exacerbations of COPD were eligible to participate in the present study. The participants underwent all conventional tests to identify etiology of microbial pathogenesis. The primary outcome was the percentage of different microbiological pathogens causing AE-COPD. A comparative microbiological analysis of the patients with overlapping asthma-COPD (ACO) and pure COPD was performed. Results: We included 1,186 patients with AE-COPD. Patients with pure COPD constituted 87.9% and those with ACO accounted for 12.1%. Nearly half of the patients used an inhaled corticosteroid-containing regimen and one-fifth used systemic corticosteroids. Respiratory pathogens were found in 55.3% of all such patients. Bacteria and viruses were detected in 33% and 33.2%, respectively. Bacterial and viral coinfections were found in 10.9%. The most frequently detected bacteria were Pseudomonas aeruginosa (9.8%), and the most frequently detected virus was influenza A (10.4%). Multiple bacterial infections were more likely to appear in ACO than in pure COPD (8.3% vs. 3.6%, p=0.016). Conclusion: Distinct microbiological patterns were identified in patients with moderate-to-severe AE-COPD in South Korea. These findings may improve evidence-based management of patients with AE-COPD and represent the basis for further studies investigating infectious pathogens in patients with COPD.

• Pediatric Infection and Vaccine
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• v.16 no.2
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• pp.142-149
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• 2009

Purpose : The aim of this study was to determine the diagnostic value of serum procalcitonin (PCT) compared with that of C-reactive protein (CRP) and the total white blood cell count (WBC) in predicting bacterial infections in febrile infants<6 months of age. Methods : A prospective study was performed with infants <6 months of age who were admitted to the Department of Pediatrics with a fever of uncertain source between July and September 2008. Spinal taps were performed according to clinical symptoms and physical examination. Serum PCT levels were measured using an enzyme-linked fluorescent assay. Results : Seventy-one infants (mean age, 2.62 months) were studied. Twenty-six infants (36.6%) had urinary tract infections (UTIs), and 22 infants (31.0%) had viral meningitis. The remaining infants had acute pharyngitis (n=1), herpangina (n=1), upper respiratory tract infections (n=7), acute bronchiolitis (n=8), acute gastroenteritis (n=4), and bacteremia (n=2). The median WBC and CRP levels were significantly higher in infants with UTIs than in infants with viral meningitis. However, there were no differences in the median PCT levels between the groups (0.14 ng/mL vs. 0.11 ng/mL, P=0.419). The area under the receiver operating characteristic curve was 0.792 (95% CI, 0.65-0.896) for WBC, 0.77 (95% CI, 0.626-0.879) for CRP, and 0.568 (95% CI, 0.417-0.710) for PCT. An elevated WBC count (>11,920/${\mu}L$) and an increased CRP level (>1.06mg/dL) were significant predictors of UTIs based on multiple logistic regression analysis. Conclusion : Serum PCT concentrations should be interpreted with caution in infants <6 months of age with a fever of uncertain source.