Objective To explore the clinical application of FP-PCR method to detect MP-DNA.Methods Five hundred and sixty-three children suspected of MP infection were enrolled in experimental group. FP-PCR was adopted to detect MP-DNA. MP-DNA was re-detected later in 60 children. At the same time,MP-Ab (MP antibody) was detected by means of particle agglutination. MP-Ab was re-detected one or two weeks later. Also 20 healthy children were selected as the control group. Results The positive rate of MP-DNA and MP-Ab were 34. 99% and 35.52% respectively,which showed no significant difference (x2 =0. 31, P > 0. 05). The coincidence of the two methods was 97. 69%. But the positive rate of MP-DNA was significantly higher than that of MP-Ab in the early stage(30. 48% vs 10. 16%) (x2 = 74. 46, P < 0. 05).The sensitivity and specificity of FP-PCR were 96. 00% and 98.62% respectively. The result of reviewed MP-DNA was consistent with the clinical diagnosis. Conclusion FP-PCR method is very sensitive, convenient and stable. It is fit for the clinical application ,especially the diagnosis of early MP infection. It helps to identify those who had been infected with MP before.

Objectives To analyze the clinical characteristics, treatment and prognosis of necrotizing pneumonia caused by Mycoplasma pneumoniae (MP) infection in children. Method The clinical data of children with necrotizing pneumonia cause by MP infection from October 2016 to October 2017 were retrospectively analyzed. Results A total of 26 children (10 males and 16 females) with an average age of (5.76±2.60) years, were enrolled in the study. All children were characterized by fever and cough. High fever ( ≥ 39.0 ℃) was seen in 23 cases (88.5％) and the total duration of fever was (16.88±7.42) days. Pulmonary auscultation showed a reduction in respiratory sounds in all children. The range of peripheral blood leukocytes were (9.0～36.8) ×109/L, mean peak neutrophil ratio was (69.2±13.2) ％, and the range of C-reactive protein (CRP) was (1～202.5) mg/L. The mean value of lactic dehydrogenase (LDH) was (448±247) U/L. At the beginning of the disease, the chest images showed homogeneous solid high-density images over the whole lung lobe and 20 cases (76.9％) were complicated with pleural effusion. At the later stage, lung CT showed thin-walled cavities or multiple air-containing cysts on the basis of lung consolidation. Fiberoptic bronchoscopy showed lumen obstruction caused by mucus plugs in 23 cases (88.5％) . All the children were treated with methylprednisolone. The dose of 2 mg/ (kg·d) was effective in 21 cases and the fever was relieved in 5 cases after the dose was adjusted to 4 mg/ (kg·d) , and the average hormone application time was (13.08 ± 8.38) d. The median length of hospital stay was [16.5 (7～32) ] d. Two cases were lost to follow-up and 24 cases finished 6-month follow-up. Lung CT showed almost complete recovery of the lungs in 16 cases, residual pleural hypertrophy in 5 cases, and bronchiectasis in 1 case and bronchiolitis obliterans in 2 cases. Conclusion Necrotic pneumonia in children caused by MP infection is characterized by persistent high fever, decreased respiratory sounds, lung consolidation and mucus plugs induced lumen obstruction. The prognosis is relatively good after active anti-infection and hormone therapy.

Objective:To explore the clinical characteristics of Mycoplasma pneumoniae (MP) bronchiolitis to provide references for clinical prevention and treatment.Methods:From January 2019 to January 2020, the clinical data of children diagnosed with MP bronchiolitis in the Department of Respiratory 2 of Hebei Children′s Hospital were retrospectively collected and analyzed, and the patients were followed up to observe the prognosis.Results:Among the 67 children, there were 39 boys and 28 girls, with age of 5 (1-14) years.All the children had cough, 63 cases (94.0%) had fever, 49 cases (77.8%) had high fever (≥39.0 ℃), and the median total fever course was 8(1-27) d; 10 cases (14.9%) had wheezing; 5 cases (7.5%) had dyspnea; 3 cases (4.5%) had hypoxemia; wet rales were heard in 58 cases (86.6%) and wheezing in 10 cases (14.9%). Forty-eight patients (71.6%) had family allergy history or personal allergy history.The average value of peripheral blood white blood cells was (8.6±2.6)×10 9/L; the me-dian of C reactive protein was 9.1(0.5-55.6) mg/L, of which 7 cases (10.4%) were ≥30 mg/L; the median of lactate dehydrogenase was 278(181-590) U/L.Tree bud sign and central lobular nodules were the main findings of high-resolution CT of the chest.Among them, 45 cases (67.2%) had bilateral lesions, 38 cases (56.7%) involved ≥3 lung lobes, and 22 cases (32.8%) had a little lung consolidation, 19 cases (28.4%) had a small amount of pleural effusion.The bronchoscopic features of 35 children (52.2%): 71.4%(25/35 cases) showed white flocculent and cord-like secretions, 17.1%(6/35 cases) displayed mucus plugs blocking the lumen, and 10.9%(4/35 cases) showed no-dular protrusions and granulation tissue hyperplasia.All children were treated with Azithromycin sequentially; 42 children (62.7%) were treated with low-dose hormones, and the average initiation time was on day (10.62±2.71) and the median course was 14(2-42) d. Sixty-seven cases were followed up for half a year, of which 61 cases (91.0%) had almost complete lung recovery, and 6 cases (9.0%) developed bronchiolitis obliterans (BO). Conclusions:MP bronchiolitis mostly occurs in infants and preschool children with a family history of allergies or personal allergies.Fever and cough are the main clinical manifestations.In severe cases, dyspnea and hypoxemia may occur.The physical signs of the lungs are mainly include wet rales, some of which are wheezing.White flocculent and cord-like secretions are the main manifestations of bronchoscopy.After active treatment, most children have a good prognosis, and some children may develop BO.