• Pediatric Infection and Vaccine
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• v.12 no.1
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• pp.86-94
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• 2005

Purpose : Recently, it has been reported that the prevalence of mycoplasam pneumonia in infants is increasing. We studied the change of prevalence and clinical features in infants for recent three years. Methods : We evaluated the clinical records of 206 patients diagnosed as mycoplasma pneumonia during Mar. 2000~Feb. 2003. We retrospectively analyzed epidemiologic, clinical, serologic and radiologic difference between children younger than 24 months and others. Results : Among 206 patients, 111 were boys and 95 were girls. Mean age of onset was $5.12{\pm}2.91$ years and lowered annually(P>0.05). 28 patinets(13.6%) were younger than 24 months and annual prevalence in this group increased(P<0.05). Main clinical features included cough, fever, coarse breathing sound(=sputum), rhinorrhea and dyspnea. There was no clinical difference between children younger than 24 months and others, except for rhinorrhea and dyspnea which more developed frequently in children younger than 24 months (P<0.05). There was also no serologic and radiologic difference for these groups. Conclusion : Annual mean age of onset lowered and annual prevalence of younger than 24 months increased with mycoplasma pneumonia. Therefore, we need careful attention to differentiate Mycoplasma pneumoniae as causal organism of pneumonia in children younger than 24 months.

• Clinical and Experimental Pediatrics
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• v.61 no.9
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• pp.291-300
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• 2018

Purpose: Understanding changes in pathogen and pneumonia prevalence among pediatric pneumonia patients is important for the prevention of infectious diseases. Methods: We retrospectively analyzed data of children younger than 18 years diagnosed with pneumonia at 117 Emergency Departments in Korea between 2007 and 2014. Results: Over the study period, 329,380 pediatric cases of pneumonia were identified. The most frequent age group was 1-3 years old (48.6%) and the next was less than 12 months of age (17.4%). Based on International Classification of Diseases, 10th revision diagnostic codes, confirmed cases of viral pneumonia comprised 8.4% of all cases, pneumonia due to Mycoplasma pneumoniae comprised 3.8% and confirmed cases of bacterial pneumonia 1.3%. The prevalence of confirmed bacterial pneumonia decreased from 3.07% in 2007 and 4.01% in 2008 to 0.65% in 2014. The yearly rate of pneumococcal pneumonia also decreased from 0.47% in 2007 to 0.08% in 2014. A periodic prevalence of M. pneumoniae pneumonia (MP) was identified. Conclusion: The increased number of patients with pneumonia, bacterial pneumonia, pleural effusion, and empyema in 2011 and 2013-2014 resulted from an MP epidemic. We provide evidence that the frequency of confirmed cases of bacterial pneumonia and pneumococcal pneumonia has declined from 2007 to 2014, which can simultaneously reflect the effectiveness of the pneumococcal conjugate vaccine.

• Pediatric Infection and Vaccine
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• v.12 no.2
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• pp.135-139
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• 2005

Purpose : We investigated the clinical manifestations, radiographic and laboratory findings of children with M. pneumoniae pneumonia(MP) according to their age. Methods : A total of 75 children with MP who admitted to The Catholic University, Daejeon St. Mary's Hospital from July 2003 to February 2004, were classified into the three age groups : the ${\leq}2$ years of age(16 children), the children between 3 and 5 years of age(35 children), and the ${\geq}6$ years and older(24 patients). The diagnosis of MP was depended on the titers of anti-mycoplasma antibody that were measured 2 times, at admission and at discharge. Results : The total duration of the fever and the length of hospitalization were not different among the age groups. Although the white blood cell(WBC) value and differential was significantly different between the groups(P<0.01), a similar number in the WBC and reduced lymphocyte proportion was observed in all age groups compared to age-matched references. The patterns of pneumonia were significantly different according to age, i.e. segmental or lobar patterns were observed in 5 cases(31.3%) in the ${\leq}2$ years old group, but 16 cases(66.6%) in the >6 years old group(P<0.01). Conclusion : Although there was no difference in clinical findings according to age in MP, the radiographic finding was more severe in older children.

• Clinical and Experimental Pediatrics
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• v.48 no.2
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• pp.154-157
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• 2005

Purpose : We evaluated the epidemiologic and clinical characteristics of mycoplasma pneumonia. Methods : A total of 559 medical records of children with mycoplasma pneumonia admitted to The Catholic University of Korea, Daejeon St. Mary's Hospital, were retrospectively analyzed. Results : The mean annual number of cases was 51. There was a higher occurrence in autumn (September-November, 41.7%) and in winter(26.7%). Outbreaks of mycoplasma pneumonia were noted in 1993-94, 1997, 2001, and 2003. The age distribution showed a peak frequency of 5-6 years of age and 68.2 percent of patients were in 3-8 years of age. The male-to-female ratio was 1.2 : 1. In comparison between 1994 and 2003, there was a difference in age distribution with a peak frequency of 5-6 years of age in 1994, and of 3-4 years of age in 2003. There were outbreaks during autumn and winter in 1993-94, and during summer and autumn in 2003. Conclusion : Outbreaks of mycoplasma pneumonia occurred every 2-4 years in Daejeon in accordance with nationwide epidemics during 1993-2003. The peak incidence of age in the recent outbreak was younger than in the outbreak which occurred 10 years ago, and in outbreaks in Western countries.

• Clinical and Experimental Pediatrics
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• v.61 no.8
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• pp.258-263
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• 2018

Purpose: Macrolide-resistant Mycoplasma pneumoniae pneumonia (MPP) is characterized by prolonged fever and radiological progression despite macrolide treatment. Few studies have examined serum procalcitonin (PCT) level in children with MPP. We aimed to investigate the association of acute inflammation markers including PCT with clinical parameters in children with MPP. Methods: A total of 147 children were recruited. The diagnosis of MPP relied on serial measurement of IgM antibody against mycoplasma and/or polymerase chain reaction. We evaluated the relationships between C-reactive protein (CRP), PCT, and lactate dehydrogenase (LDH) levels and white blood cell (WBC) counts, and clinical severity of the disease. We used multivariate logistic regression analysis to estimate the odds ratio for prolonged fever (>3 days after admission) and hospital stay (> 6 days), comparing quintiles 2-5 of the PCT levels with the lowest quintile. Results: The serum PCT and CRP levels were higher in children with fever and hospital stay than in those with fever lasting ${\leq}3days$ after admission and hospital stay ${\leq}6days$. CRP level was higher in segmental/lobar pneumonia than in bronchopneumonia. The LDH level and WBC counts were higher in children with fever lasting for >3 days before compared to those with fever lasting for ${\leq}3days$. The highest quintile of PCT levels was associated with a significantly higher risk of prolonged fever and/or hospital stay than the lowest quintile. Conclusion: Serum PCT and CRP levels on admission day were associated with persistent fever and longer hospitalization in children with MPP.

• Tuberculosis and Respiratory Diseases
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• v.45 no.3
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• pp.636-642
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• 1998

The frequency of fulminant peumonia due to Mycoplasma pneumoniae is relatively rare despite the high prevalence of Mycoplasma species infection in the general population. We report a case of mycoplasma pneumonia complicated with severe ARDS, overt hemolytic anemia and hepatitis. He had high titers of antimycoplasma antibody and cold agglutinin. Despite erythromycin administration, the pneumonic infiltration on chest radiography was not resolved, and mechanical ventilation was needed for 16 days. During the therapeutic course, his hemoglobin decreased. After the administration of prednisolone, his hemoglobin increased and pneumonic infiltration was totally resolved. He had a progressively favorable course and could be discharged in relatively good clinical condition.

• Clinical and Experimental Pediatrics
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• v.53 no.2
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• pp.178-183
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• 2010

Purpose : The aim of this study was to identify mutations associated with macrolide resistance in Mycoplasma pneumoniae (MP) and to establish a cultural method to determine antimicrobial susceptibility. Methods : Nasopharyngeal aspirates (NPAs) were collected from 62 children diagnosed with MP pneumonia by a serologic method or polymerase chain reaction. The 23S rRNA and L4 ribosomal protein genes of MP were amplified and sequenced. To identify mutations in these 2 genes, their nucleotide sequences were compared to those of the reference strain M129. MP cultivation was carried out for 32 (28 frozen and 5 refrigerated) NPAs and M129 strain using Chanock's glucose broth and agar plate in a 5% $CO_2$ incubator at $37^{\circ}C$ and examined at 2-3 day intervals for 6 weeks. Results : Among the 62 specimens, 17 had M144V mutations in ribosomal protein L4. The A2064G mutation was observed in 1 specimen; its 23S rRNA gene was successfully sequenced. Culture for MP was successful from the M129 strain and 2 of the 5 NPAs that were refrigerated for no longer than 3 days. However, MP did not grow from the 28 NPAs that were kept frozen at $-80^{\circ}C$ since 2003. Conclusion : We found the M144V mutation of L4 protein to be common and that of domain V of 23S rRNA gene was relatively rare among MP. Studies on the prevalence of macrolide-resistant MP and the relationship between the mutations of 23S rRNA gene and ribosomal protein L4 will aid in understanding the mechanism of macrolide resistance in MP.

• Tuberculosis and Respiratory Diseases
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• v.66 no.5
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• pp.358-364
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• 2009

Background: The appropriate empirical antimicrobial choice in the treatment of community-acquired pneumonia (CAP) should be advocated by community-based information on the etiologic pathogens, their susceptibility to antimicrobials, clinical characteristics and outcomes. Jeju is a geographically isolated and identical region in Korea. However, there is no regional reference on adult CAP available. This study investigated the etiologic agents and clinical outcomes of adult patients diagnosed with CAP in Jeju, Korea, to help guide the empirical antimicrobial choice. Methods: A prospective observational study for one year in a referral hospital in Jeju, Korea. Patients diagnosed with CAP were enrolled with their clinical characteristics. Microbiological evaluations to identify the etiologic agents in the adult patients with CAP were performed with blood culture, expectorated sputum smear and culture, antibody tests for mycoplasma, chlamydophila, and antigen tests for legionella and pneumococcus. The clinical outcomes of the initial empirical treatment were analyzed. Results: Two hundred and three patients with mean age of 64 and 79 females were enrolled. Ten microbials from 90 cases (44.3%) were isolated and multiple isolates were confirmed in 30. Among the microbial isolates, S. pneumoniae (36.3%) was the most common, followed by M. pneumoniae (23.0%), C. pneumoniae (17.0%), S. aureus (9.6%) and P. aeruginosa (5.9%). The initial treatment failure (23.8%) was related to the isolation of polymicrobial pathogens, elevated inflammatory markers, and the presence of pleural effusion. Among the 30 isolates of S. pneumoniae, 16 (53.3%) were not susceptible to penicillin, and 19 isolates (63.3%) to erythromycin and clarithromycin. However, 29 isolates (96.7%) were susceptible to levofloxacin and ceftriaxone. Conclusion: S. pneumoniae, M. pneumoniae, S. aureus, and P. aeruginosa are frequent etiologic agents of adult CAP in Jeju, Korea. The clinical characteristics and antibiotic resistance should be considered when determining the initial empirical antimicrobial choice. Respiratory quinolone or ceftriaxone is recommended as an empirical antimicrobiotic in the treatment of adult CAP in Jeju, Korea.

• Tuberculosis and Respiratory Diseases
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• v.44 no.5
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• pp.1072-1082
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• 1997

Background : To characterize the clinical features and determine the prognostic factors of severe community-acquired pneumonia. This study is the first of its kind in Korea. Methods : Recruited were 40 patients diagnosed as severe community-acquired pneumonia in Hallym University Hospital from January 1, 1989 through July 31, 1996. Patients were analysed retrospectively for age, sex, underlying disease, respiration rate, hypoxemia, requirement of mechanical ventilation, involvement on chest radiograph, shock, and the serum concentration of BUN and albumin. All parameters were compared between survived and dead group. Results : Male to female ratio was 2.07 : 1. The mean age was $63.1{\pm}17.5$years(range 25~90years) with 65% of patients aged equal to or more than 60. The major underlying diseases were old pulmonary tuberculosis(12.5%), chronic obstructive pulmonary disease(7.5%), bronchial asthma(5%), bronchiectasis(2.5%), and diabetes mellitus(22.5%). Microbiologic diagnosis was made in 26 out of 40 patients(65%). The most common causative organism was S. pneumoniae(17.5%, 7/40) followed by S. aureus(15.0%, 6/40), K. Pneumoniae(12.5%, 5/40), M. tuberculosis(7.5%, 3/40), H. influenzae(2.5%, 1/40), coagulase negative staphylococcus(2.5%, 1/40), P. aeruginosa(2.5%. 1/40), E. cloaceae(2.5%, 1/40), and E. coli(2.5%, 1/40). M. pneumoniae was detected in no patient. The most frequent drugs administered in single or combination therapy were aminoglycosides(75%, 30/40), second- and third-generation cephalosporin(40%, 16/40 and 27.5%, 11/40), macrolides(27.5%, 11/40), and amoxicillin/clavulanic acid(22.5%, 9/40). Of the 40 patients, 14 died of severe community-acquired pneumonia(37.5%). Among them, seven patients (50%) expired within 72h of hospital arrival. According to multivariate analysis, mortality was significantly associated with requirement of mechanical ventilation, bilateral pulmonary involvement, and serum albumins$\leq$3.0g/dl. Conclusion : An understanding of the clinical characteristics and prognostic factors in severe community-acquired pneumonia identified in this study will optimize therapeutic approach in this disease and help decreasing its notorious mortality rate.

• Pediatric Infection and Vaccine
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• v.14 no.1
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• pp.124-128
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• 2007

Bronchiolitis obliterans is a clinical syndrome of chronic obstruction associated with inflammatory changes in the small airways. There are marked variations in the epidemiology of this disease. In childhood, bronchiolitis obliterans has been described as a result of a number of infections such as adenovirus, measles, Bordetella pertussis, Mycoplasma pneumoniae, and influenza A infection. Most common agents are adenovirus types 3, 7, and 21. Diagnosis of bronchiolitis obliterans can be made based on clinical findings, high resolution computed tomography (HRCT) and lung biopsy. In addition to diagnosis, treatment is not yet clearly established. The authors experienced a case of bronchiolitis obliterans developed in 3 year-old girl who suffered from type 7 adenoviral pneumonia. She had been hospitalized and treated for 15 days due to pneumonia. After discharge, productive cough was not improved and auscultation revealed wheezing. HRCT demonstrated multifocal mosaic patterns suggesting bronchiolitis obliterans. She was managed with inhaled steroid and bronchodilator, and her symptoms were improved. However, follow up HRCT showed no interval change.