• Journal of Microbiology and Biotechnology
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• v.31 no.8
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• pp.1109-1114
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• 2021

Chlamydia pneumoniae is a type of pathogenic gram-negative bacteria that causes various respiratory tract infections including asthma. Chlamydia species infect humans and cause respiratory infection by rupturing the lining of the respiratory which includes the throat, lungs and windpipe. Meanwhile, the function of interleukin-4 (IL-4) in Ch. pneumoniae respiratory infection and its association with the development of airway hyperresponsiveness (AHR) in adulthood and causing allergic airway disease (AAD) are not understood properly. We therefore investigated the role of IL-4 in respiratory infection and allergy caused by early life Chlamydia infection. In this study, Ch. pneumonia strain was propagated and cultured in HEp-2 cells according to standard protocol and infant C57BL/6 mice around 3-4 weeks old were infected to study the role of IL-4 in respiratory infection and allergy caused by early life Chlamydia infection. We observed that IL-4 is linked with Chlamydia respiratory infection and its absence lowers respiratory infection. IL-4R α2 is also responsible for controlling the IL-4 signaling pathway and averts the progression of infection and inflammation. Furthermore, the IL-4 signaling pathway also influences infection-induced AHR and aids in increasing AAD severity. STAT6 also promotes respiratory infection caused by Ch. pneumoniae and further enhanced its downstream process. Our study concluded that IL-4 is a potential target for preventing infection-induced AHR and severe asthma.

• Tuberculosis and Respiratory Diseases
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• v.59 no.1
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• pp.47-52
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• 2005

Background : Chlamydia pneumoniae is a clinically important pathogen, the diagnosis of such infection being based mainly on serology. Microimmunofluorescence (MIF) is the current standard diagnostic method, but is subjective and time-consuming, so the authors tested the serology of chronic cough patients using an EILSA method for the Chlamydial antibody, which is a more objective method, and compared the results with those of the standard method. Method : Thirty-five patients, who visited Kangwon National University Hospital between August 2003 and July 2004, were evaluated. A MIF and ELISA tests were used to determine C. pneumoniae antibody titers. Nasopharyngeal aspirates were examined by polymerase chain reaction (PCR). The Spearman rank correlation test was used for data analysis. Results : Sensitivities of ELISA for IgG, IgA and IgM, as judged by MIF, were 84.0, 84.0 and 40.0% and the specificities were 60.0, 60.0 and 96.7%, respectively. Three patients were Chlamydia PCR positive. Conclusion : ELISA can be a useful tool for studying the seroprevalence of Chlamydia pneumoniae. However, further studies will be required prior to its clinical use.

• Tuberculosis and Respiratory Diseases
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• v.69 no.6
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• pp.426-433
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• 2010

Background: Persistent cough has recently been found to be associated with Chlamydia pneumoniae infection. We aimed to investigate the infection rate of C. pneumonia in adult patients with chronic cough. Methods: We recruited 68 patients with persistent cough lasting in excess of 3 weeks, who visited Kangdong Sacred Heart Hospital from January 2005 to August 2005. On the first visit, chest and paranasal sinuses radiography, skin prick test of common allergens, and induced sputum samples for C. pneumoniae were performed in all of patients. Further evaluation for diagnosis included a methacholine provocation test and eosinophil counts in induced sputum. Results: The most common cause of chronic cough was upper airway cough syndrome (UACS) (26.5%), followed by eosinophilic bronchitis (20.6%) and cough variant asthma (16.2%). Idiopathic chronic cough was the cause in 33.8% of patients. The mean duration of cough was 11.7 months. C. pneumoniae was isolated by polymerase chain reaction (PCR) from one patient who had upper respiratory air way syndrome. Conclusion: Chlamydia pneumoniae appears to have a minor role as a cause of chronic cough in patients.

• Tuberculosis and Respiratory Diseases
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• v.53 no.5
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• pp.569-576
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• 2002

Background : Chlamydia pneumoniae is one of common causes in upper and lower respiratory infections. Isolating C. pneumoniae from clinical specimens is very difficult due to the characteristics of the organism. Recently, we succeeded in isolating C. pneumoniae from a Korean patient, who suffered from acute pharyngitis. This is the first isolate from a clinical specimen in Korea. Methods : We attained a nasopharyngeal swab from a 22-year-old female patient, and inoculated it on a monolayer of the Hep-2 cell line. After 8 passages, we found the inclusion bodies of C. pneumoniae by an immunofluorescence(IF) test. The species-specific monoclonal antibody IF staining and species-specific PCR were done to confirm the species of the isolate, and electron microscopy was used to characterize the morphology. Results : The isolated was confirmed to be C. pneumoniae by species-specific IF and PCR, and the strain was named LKK-1. The shape of the elementary body was round and with a narrow periplasmic space, as shown by electron microscopy, which is similar to the Japanese strain, but not the Western strain. Conclusion : We succeeded in isolating C. pneumoniae from a 22-year-old patient with acute pharyngitis, which is the first isolate in Korea. In the future, this Korean strain will be useful to the study of C. pneumoniae.

• Journal of Microbiology
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• v.42 no.4
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• pp.299-304
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• 2004

To investigate the presence of infectious agents in human atherosclerotic arterial tissues. Atherosclerotic plaques were removed from 128 patients undergoing carotid endarterectomy or other bypass proce­dures for occlusive disease, and from twenty normal arterial wall samples, obtained from transplant donors with no history of diabetes, hypertension, smoking, or hyperlipidemia. Using the polymerase chain reaction (PCR) or reverse transcription-PCR, these samples were analyzed for the presence of Chlamydia pneumoniae, cytomegalovirus, enterovirus, adenovirus, herpes simplex viruses types 1 and 2, and Epstein-Barr virus. The amplicons were then sequenced, and phylogenetic analyses were per­formed. Enteroviral RNA was found in 22 of 128 atherosclerotic vascular lesions $(17.2\%),$ and C. pneu­moniae and cytomegalovirus were each found in 2 samples $(1.6\%).$ In contrast, adenovirus, herpes simplex viruses, and Epstein-Barr virus were not identified in any of the atherosclerotic samples. Enterovirus was detected in 6/24 $(25.0\%)$ aortas, 7/33 $(21.2\%)$ carotid arteries, 6/40 $(15.0\%)$ femoral arteries, and 3/31 $(9.7\%)$ radial arteries of patients with chronic renal failure. There were no infectious agents detected in any of the control specimens. Using phylogenetic analysis, the enterovirus isolates were clustered into 3 groups, arranged as echovirus 9 and coxsackieviruses Bl and B3. Enteroviral RNA was detected in $17.2\%$ of atherosclerotic plaques, but was not observed in any of the control spec­imens. This suggests a connection between enteroviral infection and atherosclerosis. These findings dif­fer from those of other studies, which found more frequent incidence of C. pneumoniae and cytomegalovirus infection in atherosclerotic plaques.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.6
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• pp.2819-2822
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• 2012

Objective: To assess induction effects of Chlamydia pneumoniae (Cpn) on lung cancer in rats. Methods: A lung cancer animal model was developed through repeated intratracheal injection of Cpn (TW-183) into the lungs of rats, with or without exposure to benzo(a)pyrene (Bp). Cpn antibodies (Cpn-IgA, -IgG, and -IgM) in serum were measured by microimmunofluorescence. Cpn-DNA or Cpn-Ag of rat lung cancer was detected through polymerase chain reaction or enzyme-linked immunosorbent assay. Results: The prevalence of Cpn infection was 72.9% (35/48) in the Cpn group and 76.7% (33/43) in the Cpn plus benzo(a)pyrene (Bp) group, with incidences of lung carcinomas in the two groups of 14.6% (7/48) and 44.2% (19/43), respectively (P-values 0.001 and <0.000 compared with normal controls). Conclusions: A rat model of lung carcinoma induced by Cpn infection was successfully established in the laboratory for future studies on the treatment, prevention, and mechanisms of the disease.

• Clinical and Experimental Pediatrics
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• v.63 no.12
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• pp.469-476
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• 2020

The major pathogens that cause atypical pneumonia are Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Legionella pneumophila. Community-acquired pneumonia (CAP) caused by M. pneumoniae or C. pneumoniae is common in children and presents as a relatively mild and self-limiting disease. CAP due to L. pneumophila is very rare in children and progresses rapidly, with fatal outcomes if not treated early. M. pneumoniae, C. pneumoniae, and L. pneumophila have no cell walls; therefore, they do not respond to β-lactam antibiotics. Accordingly, macrolides, tetracyclines, and fluoroquinolones are the treatments of choice for atypical pneumonia. Macrolides are the first-line antibiotics used in children because of their low minimum inhibitory concentrations and high safety. The incidence of pneumonia caused by macrolide-resistant M. pneumoniae that harbors point mutations has been increasing since 2000, particularly in Korea, Japan, and China. The marked increase in macrolide-resistant M. pneumoniae pneumonia (MRMP) is partly attributed to the excessive use of macrolides. MRMP does not always lead to clinical nonresponsiveness to macrolides. Furthermore, severe complicated MRMP responds to corticosteroids without requiring a change in antibiotic. This implies that the hyper-inflammatory status of the host can induce clinically refractory pneumonia regardless of mutation. Empirical macrolide therapy in children with mild to moderate CAP, particularly during periods without M. pneumoniae epidemics, may not provide additional benefits over β-lactam monotherapy and can increase the risk of MRMP.

• Tuberculosis and Respiratory Diseases
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• v.58 no.3
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• pp.257-266
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• 2005

Background : The study of pneumonia among young men living in a group is rare. prospective study was conducted to determine the etiology, and compare the effects of macrolide and second-generation cephalosporin on the treatment of pneumonia among combat policemen. Patients and Methods : From January 2003 to April 2004, Fifty-two patients with pneumonia were treated with either azithromycin(n=25) or cefuroxime(n=27). In order to determine the cause of the pneumonia, culture studies and serologic tests for antibodies to Mycoplasma pneumoniae and Chlamydia pneumoniae were carried out. During the two weeks of medication, the Chest X-rays, blood tests and culture studies(if necessary) were followed weekly. A serologic study was followed at the end of the second week. Results : The main pathogens for pneumonia among combat policemen were Mycoplasma pneumoniae(50.0%), Chlamydia pneumoniae(10.8%), and Streptococcus pneumoniae(3.8%). The treatment was successful in most cases(51/52 cases, 98.1%). The effects of azithromycin and cefuroxime were similar (96.0% vs 100%, p>0.05). In one patient who had taken azithromycin, the clinical and radiological findings did not improved until intravenous second generation ce phalosporin had been infused. Conclusion : Atypical pathogens were the main causes of the pneumonia in the combat policemen, and the effects of macrolide and second generation cephalosporin for pneumonia were similar. However, further studies will be needed to determine if single therapy with macrolide is possible.

• Clinical and Experimental Pediatrics
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• v.52 no.12
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• pp.1358-1363
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• 2009

Purpose:The aim of this study was to determine the prevalence of asymptomatic nasopharyngeal carriages in children using a multiplex reverse transcriptase-polymerase chain reaction (mRT-PCR) assay kit. Methods:We obtained nasopharyngeal swabs from 33 children without any underlying disease from July 25 to July 28, 2008. The children were free from the signs of respiratory tract infections at the time of sampling. DNA was extracted from the swabs and subjected to multiplex RT-PCR using a primer set for the detection of pneumococci ($Seeplex^{(R)}$ PneumoBacter ACE Detection Seegene, Seoul, Korea). The amplified PCR products were separated on 2% agarose gels and stained with either ethidium bromide or screen tape system (Lab901 Scotland, UK). Results:A total of 33 children (male, 15 female, 18) aged between 3.2 and 16.3 (median, 8.2) years were included in this study. The mRT-PCR detected colonized bacteria (Streptococcus pneumoniae, Hemophilus influenzae, Chlamydia pneumoniae, and Bordetella pertussis) in 30 children (90.9%). Of these, 13 children (39.4%) showed more than 2 bacteria: 12 children were positive for 2 bacteria (S. pneumoniae and H. influenzae) and 1 child was positive for 3 bacteria (S. pneumoniae, H. influenzae, and C. pneumoniae). Conclusion:mRT-PCR was found to be a sensitive tool for the detection of asymptomatic nasopharyngeal carriages. Clinical significances of the bacteria detected by mRT-PCR will have to be evaluated in the future.

• 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.