• 대한수의학회지
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• 제48권3호
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• pp.267-274
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• 2008

This study was to evaluate the efficacy of single dose Mycoplasma hyopneumoniae (M. hyo)-vaccination in the swine farms which had different serological patterns of porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2). A minimum of 240 pigs from each farm was applied, allocating M. hyo vaccinated and control groups. The PRRSV and PCV2 infections were analyzed by serological method (commercial ELISA kit). After administrating pigs a single dose of M. hyo vaccine or control saline at 3 weeks of age, serum antibodies to M. hyo, PRRSV and PCV2 were monitored at 4, 10, 16 and 22 weeks of age. Mortality, weight changes, feed conversion ratio (FCR) and lung score were also evaluated. A single-dose vaccination of M. hyo bacterin was efficacious to reduce mycoplasmal lung lesions and induce good humoral immune response. However, FCR was improved only in one of the three farms where showed seronegative status to both PRRSV and PCV2 in the period from 4 to 16 weeks of age. These results might imply that M. hyo vaccine alone could not overcome the PRRSV and PCV2 infection-associated wasting in the field condition. Therefore, the control of PRRSV and PCV2 should be considered to obtain the better effects of M. hyo vaccination.

• Clinical and Experimental Pediatrics
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• 제57권6호
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• pp.271-277
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• 2014

Purpose: A nationwide outbreak of Mycoplasma pneumoniae pneumonia (MP) refractory to macrolide antibiotics occurred in Korea during 2011. Steroid therapy has been reported to be both efficacious and well tolerated in pediatric patients with refractory MP. We compared clinical features and laboratory characteristics between children with refractory MP requiring steroid treatment and those with macrolide-responsive MP and evaluated the risk factors associated with refractory MP. Methods: We investigated 203 children who were admitted to our institution with MP from June to November 2011. Refractory MP was defined by persistent fever over $38.3^{\circ}C$ with progressive pulmonary consolidation or pleural effusion despite administration of appropriate macrolide antibiotics for 5 days or longer after admission. Steroid therapy was initiated on the fifth day after admission for refractory cases. Results: There were 26 patients with refractory MP requiring steroid therapy. The mean duration of steroid therapy was 5.4 days and most of the patients were afebrile within 24 hours after initiation of steroid therapy. The prevalence of refractory MP was higher in patients with pleural effusion, lobar pneumonia affecting more than 2 lobes, higher levels of serum lactate dehydrogenase, increased oxygen requirements, and longer duration of hospitalization. Atopic sensitization and history of asthma were also associated with refractory MP after adjusting for age and gender. Conclusion: Children with refractory MP had more severe pneumonia. Atopic sensitization and history of asthma may be risk factors for refractory MP requiring steroid therapy in Korean children.

• Clinical and Experimental Pediatrics
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• 제54권3호
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• pp.123-127
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• 2011

Purpose: Kawasaki disease (KD) is the main cause of acquired heart disease in children. In addition to cardiovascular involvement, many complications have been recognized in KD. However, respiratory complications have been rarely reported. We investigated the differences in clinical characteristics, laboratory findings, radiography findings, and echocardiography findings of Mycoplasma pneumoniae infection and other types of pneumonia in KD patients. Methods: Among 358 patients with KD, 54 developed concurrent pneumonia. Among the 54 patients, 12 (22.2%) with high titers of anti-M. pneumoniae antibody (AMA) (>1:640) were grouped in the M. pneumoniae group and 42 were included in the control group. Serum AMA was measured in each patient. Clinical laboratory findings and total duration of fever were analyzed. Results: The duration of fever, serum hemoglobin, white blood cell count, platelet count, erythrocyte sedimentation rate, C-reactive protein level, albumin level, and the incidence of coronary arterial lesions showed no statistical difference in the 2 groups. Neutrophil count was significantly higher in the M. pneumoniae group than in the control group. Among various radiography findings observed in pneumonia, consolidation and pleural effusion were more frequent in the M. pneumoniae group than in the control group. On the other hand, parahilar peribronchial opacification, diffuse interstitial lesion, and normal findings prevailed in the control group. Conclusion: KD patients can have concurrent infections, especially pulmonary symptoms. The cause of KD is likely to be associated with M. pneumoniae infection. Thus, immediate treatment of M. pneumoniae infection in KD patients is very important.

• Clinical and Experimental Pediatrics
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• 제57권4호
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• pp.186-192
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• 2014

Purpose: The prevalence of macrolide-resistant Mycoplasma pneumoniae (MRMP) has increased worldwide. The aim of this study was to estimate the proportion of MRMP in a tertiary hospital in Korea, and to find potential laboratory markers that could be used to predict the efficacy of macrolides in children with MRMP pneumonia. Methods: A total of 95 patients with M. pneumoniae pneumonia were enrolled in this study. Detection of MRMP was based on the results of specific point mutations in domain V of the 23S rRNA gene. The medical records of these patients were reviewed retrospectively and the clinical course and laboratory data were compared. Results: The proportion of patients with MRMP was 51.6% and all MRMP isolates had the A2063G point mutation. The MRMP group had longer hospital stay and febrile period after initiation of macrolides. The levels of serum C-reactive protein (CRP) and interleukin-18 in nasopharyngeal aspirate were significantly higher in patients who did not respond to macrolide treatment. CRP was the only significant factor in predicting the efficacy of macrolides in patients with MRMP pneumonia. The area under the curve for CRP was 0.69 in receiver operating characteristic curve analysis, indicating reasonable discriminative power, and the optimal cutoff value was 40.7 mg/L. Conclusion: The proportion of patients with MRMP was high, suggesting that the prevalence of MRMP is rising rapidly in Korea. Serum CRP could be a useful marker for predicting the efficacy of macrolides and helping clinicians make better clinical decisions in children with MRMP pneumonia.

• 대한수의학회지
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• 제51권2호
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• pp.129-137
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• 2011

Swine diseases could be caused by unrecognized or minor pathogens. In this study, two unknown cytopathogenic agents were isolated from swine, through cell culture. In order to identify these two cytopathogenic agent (designated CP129 and #2045-7), a particle associated nucleic acids PCR (PANPCR) from previous paper was used with simple modification. The cloning procedure was more specified in this study by adding cell control system. According to the modified PAN-PCR, two and four agentsspecific DNA sequences were obtained from CP129 and #2045-7, respectively, and they were identified as Mycoplasma (M.) hyorhinis and Mammalian orthoreovirus by nucleotide BLAST. Since M. hyorhinis (CP129) was filterable and non-visible by microscope, this unusual virus-like nature of M. hyorhinis (CP129) was discussed. Especially, the reovirus (#2045-7) was a serotype 3 and a triple reassortant among three serotypes of reoviruses. It was grouped with recently reported reoviruses from disease cases (swine, human and feline), based on the genetic analysis of L1 and S1 partial sequences. In conclusion, two unknown cytopathogenic agents were successfully identified using modified PAN-PCR with cell control system and they were characterized in this study.

• Journal of Korean Medical Science
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• 제33권43호
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• pp.268.1-268.11
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• 2018

Background: We aimed to compare the therapeutic efficacy of prolonged macrolide (PMC), corticosteroids (CST), doxycycline (DXC), and levofloxacin (LFX) against macrolide-unresponsive Mycoplasma pneumoniae (MP) pneumonia in children and to evaluate the safety of the secondary treatment agents. Methods: We retrospectively analyzed the data of patients with MP pneumonia hospitalized between January 2015 and April 2017. Macrolide-unresponsiveness was clinically defined with a persistent fever of ${\geq}38.0^{\circ}C$ at ${\geq}72$ hours after macrolide treatment. The cases were divided into four groups: PMC, CST, DXC, and LFX. We compared the time to defervescence (TTD) after secondary treatment and the TTD after initial macrolide treatment in each group with adjustment using propensity score-matching analysis. Results: Among 1,165 cases of MP pneumonia, 190 (16.3%) were unresponsive to macrolides. The proportion of patients who achieved defervescence within 48 hours in CST, DXC, and LFX groups were 96.9% (31/33), 85.7% (12/14), and 83.3% (5/6), respectively. The TTD after initial macrolide treatment did not differ between PMC and CST groups (5.1 vs. 4.2 days, P = 0.085), PMC and DXC groups (4.9 vs. 5.7 days, P = 0.453), and PMC and LFX groups (4.4 vs. 5.0 days, P = 0.283). No side effects were observed in the CST, DXC, and LFX groups. Conclusion: The change to secondary treatment did not show better efficacy compared to PMC in children with macrolide-unresponsive MP pneumonia. Further studies are needed to guide appropriate treatment in children with MP pneumonia.

• Pediatric Infection and Vaccine
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• 제26권1호
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• pp.71-79
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• 2019

8세 남아가 호흡곤란과 기면증을 보이며 응급실에 내원하였다. 극도의 호흡부전을 보이고 있었고 고유량의 산소 공급을 함에도 불구하고 88-90%로 밖에 유지되지 않았고 단순 흉부 방사선 검사에서 전 폐야에 불투과도가 증가하였고 중등도의 흉수를 보였다. 마이코플라스마 폐렴 진단 하에 정맥 macrolide 를 포함한 항생제 치료를 시작하였으나 2병일 째 간, 신장에 다기관 부전 및 급성 호흡부전 증상을 보였다. 정맥-정맥 체외순환막성산소화기를 삽입하였고 지속적 신대체요법도 병행하였다. 18병일 째 성공적으로 체외순환막성산소화기에서 이탈하였고 저산소성 뇌 손상 없이 성공적으로 치료되었기에 본 사례를 보고한다.

• Pediatric Infection and Vaccine
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• 제26권1호
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• pp.60-65
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• 2019

항인지질항체는 자가면역 질환에서 발생할 수 있고, 때로는 마이코플라즈마와 같은 감염 후에도 발생할 수 있다. 그러나 마이코플라즈마 폐렴 후 항인지질항체의 발현과 혈전의 발생은 매우 드물게 보고되어왔다. 본 8세 환아는 마이코플라즈마 폐렴 입원 치료 중 손가락의 변색 및 감각 저하가 발생하였고 혈액검사 결과 항인지질항체 양성으로 확인되었다. 이로 인해 상완동맥 혈전증이 발생하여 혈전제거술을 시행하여 제거하였다. 양성이었던 항인지질항체는 5개월 내 다시 정상화되었다. 마이코플라즈마 폐렴의 합병증은 피부 병변을 포함하여 체내 많은 장기에 다양한 증상을 보이지만, 그 중 항인지질항체의 발현으로 인한 혈전의 발생은 치명적이므로, 마이코플라즈마 폐렴의 치료에 있어 고려해야 할 합병증의 사례를 보고한다.

• Journal of Veterinary Science
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• 제23권3호
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• pp.49.1-49.13
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• 2022

Background: Porcine circovirus type 2 (PCV2) and Mycoplasma hyopneumoniae (MHP) are economically significant pathogens in the pig industry. The use of combined vaccines against PCV2 and MHP is one of the most effective ways of protecting pigs from both diseases, and it has become a part of general management. Objectives: This study evaluated the efficacy of two new bivalent vaccines of PCV2 and MHP (Myco-X and Myco-XD) in SPF pigs. Myco-X and Myco-XD are a combined vaccine of MHP with PCV2b and PCV2d, respectively. Methods: Sixteen pigs were divided into four groups: Myco-X-vaccinated challenged, Myco-XD-vaccinated challenged, unvaccinated challenged, and unvaccinated unchallenged. Two milliliters of Myco-X were administered intramuscularly, and 0.5 mL of Myco-XD was injected intradermally at 3 wk of age. The pigs were challenged with virulent PCV2d via the intramuscular and intranasal route 4 wk post-vaccination. Results: All vaccinated pigs showed effective reduction of the clinical signs, the PCV2d load in the blood and nasal swab samples, as well as lung and lymphoid tissue lesions in the challenge test. Compared to unvaccinated challenged animals, the vaccinated challenged animals showed significantly higher (p < 0.05) levels of anti-PCV2 IgG, PCV2d-specific interferon-γ (IFN-γ), and anti-MHP IgG. Conclusions: Based on clinical, microbiological, serological, and pathological assessments, this study confirmed that both combined vaccines could protect pigs against PCV2 infection caused by PCV2d. On the other hand, further research on the efficacy evaluation of these new vaccines against the MHP challenge and PCV2d/MHP co-challenge is needed.

• 한국동물위생학회지
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• 제45권4호
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• pp.305-316
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• 2022

Bordetella (B.) bronchiseptica, Mycoplasma (M.) felis, and Chlamydia (C.) felis are considered as main bacterial pathogens of feline upper respiratory tract disease (URTD). In this study, a new triplex quantitative real-time polymerase chain reaction (tqPCR) assay was developed for the rapid and differential detection of these bacteria in a single reaction. The assay specifically amplified three bacterial genes with the detection limit of below 10 copies/reaction. The assay showed high repeatability and reproducibility, with coefficients of intra-assay and inter-assay variation of less than 1%. Based on the diagnostic results of the assay using 94 clinical samples obtained from cats with URTD signs, prevalence of B. bronchiseptica, M. felis, or C. felis was 10.6%, 36.2%, or 6.4%, respectively, indicating that the diagnostic sensitivity was comparable to those of previously reported monoplex qPCR assays. The dual infection rates for B. bronchiseptica and M. felis or M. felis and C. felis was 2.1% or 3.2%, respectively. These results indicated that M. felis has been widely spread, and its co-infection with B. bronchiseptica or M. felis has been frequently occurred in Korean cat population. The developed tqPCR assay will serve as a promising tool for etiological and epidemiological studies of these three bacterial pathogens and the prevalence data obtained in this study will contribute to expanding knowledge about the epidemiology of feline URTD in Korea.