Mycoplasma Pneumoniae Pneumonia Children Research Articles

Therapeutic effect of low molecular weight heparin on adjuvant treatment of Mycoplasma pneumoniae pneumonia with elevated D-dimer in children

Objective To investigate the therapeutic effect of low molecular weight heparin on adjuvant treatment of Mycoplasma pneumoniae pneumonia (MPP) with elevated D-dimer in children, and to summarize the clinical features of MPP with elevated D-dimer in children. Methods Ninety-three cases of MPP with elevated D-dimer in the Affiliated Children′s Hospital of Capital Institute of Pediatrics from January 2015 to October 2016 were randomly divided into the high dose group, the low dose group and the non-heparin group.All patients in 3 groups were given active anti-infection and other conventional treatment.High dose group was given subcutaneous injection of low molecular weight heparin 100 IU/kg, q12h, treatment for 5 days or D-dimer returned to normal; Low dose group was given subcutaneous injection of low molecular weight heparin 50 IU/kg, q12h for 5 days, and then D-dimer returned to normal; non-heparin group was given anti-infection and other conventional treatment.Contrast observation was performed among 3 groups for clinical symptoms and chest imaging changes before and after treatment.Also, the hospitalization days and financial costs among 3 groups were compared and the adverse reactions were observed.Another 31 patients of MPP with normal D-dimer were randomly selected for comparison with non-heparin group, including C-reactive protein(CRP), erythrocyte sedimentation rate(ESR) and other inflammatory markers, clinical symptoms, chest imaging changes, hospitalization days and the costs. Results (1)The inflammatory indicators such as CRP[(33.49±31.75) g/L], ESR[(34.59±16.25) mm/1h], cough improvement time[(7.77±2.85) d], heat back time[(5.87±2.88) d], hospitalization days[(10.87±3.50) d], hospital costs[(15 455.91±4 086.95) yuan], and chest imaging severity[ the ratio of large-area shadowing to small-area shadowing in terms of chest image severity was (13/16 cases)]of MPP with elevated D-dimer group were higher than those of MPP with normal D-dimer group[(14.83±18.97) g/L, (25.33±20.35) mm/1 h, (3.90±1.08) d, (2.81±1.99) d, (5.26±1.84) d, (7 659.85±2 216.69) yuan, 5/23 cases], and the differences were statistically significant(Z=-2.99, -2.06, -5.82, -5.21, -6.20, t=12.73, χ2=4.80, all P 0.05). D-dimer and fibrinogen degradation product(FDP) after treatment in the high dose heparin-treated group [(258.00±516.00) ng/L, (2.25±7.45) mg/L] were significantly lower than those in the non-heparin group[(1.00±691.00) ng/L, (0.70±3.10) mg/L], and the diffe-rences were statistically significant(Z=6.41, 6.54, all P<0.05). Conclusions (1)Compared with the children with MPP with elevated D-dimer, MPP children with normal D-dimer in children have more severe clinical symptoms, higher inflammatory indicators and more serious chest imaging performance.(2)Low molecular weight heparin on adjuvant treatment of elevated D-dimer children with MPP can significantly improve the clinical symptoms and promote absorption of lung disease, shorten hospitalization days, reduce hospital costs.There is no adverse reaction with short-term application.It is worthy of further promotion. Key words: D-dimer; Low molecular weight heparin; Mycoplasma pneumonia

Transcriptome Analysis of Bronchoalveolar Lavage Fluid From Children With Mycoplasma pneumoniae Pneumonia Reveals Natural Killer and T Cell-Proliferation Responses.

Mycoplasma pneumoniae pneumonia (MPP) is one of the most common community-acquired pneumonia; this study is to explore the immune-pathogenesis of children MPP. Next-generation transcriptome sequencing was performed on the bronchoalveolar lavage fluid cells from six children with MPP and three children with foreign body aspiration as control. Some of the results had been validated by quantitative real-time PCR in an expanded group of children. Results revealed 810 differentially expressed genes in MPP group comparing to control group, of which 412 genes including RLTPR, CARD11 and RASAL3 were upregulated. These upregulated genes were mainly enriched in mononuclear cell proliferation and signaling biological processes. Kyoto encyclopedia of genes and genomes pathway analysis revealed that hematopoietic cell linage pathway, natural killer cell-mediated cytotoxicity pathway, and T cell receptor signaling pathway were significantly upregulated in MPP children. In addition, significant alternative splicing events were found in GNLY and SLC11A1 genes, which may cause the differential expressions of these genes. Our results suggest that NK and CD8+ T cells are over activated and proliferated in MPP children; the upregulated IFNγ, PRF1, GZMB, FASL, and GNLY may play important roles in the pathogenesis of children MPP.

The concordance between upper and lower respiratory microbiota in children with Mycoplasma pneumoniae pneumonia

In recent years, the morbidity of Mycoplasma pneumoniae pneumonia (MPP) has dramatically increased in China. An increasing number of studies indicate that an imbalance in the respiratory microbiota is associated with respiratory infection. We selected 28 hospitalized patients infected with M. pneumoniae and 32 healthy children. Nasopharyngeal (NP) and oropharyngeal (OP) swabs were collected from healthy children, whereas NP, OP and bronchoalveolar lavage (BAL) specimens were collected from patients. Microbiota analysis was performed on all microbial samples using 16 S ribosomal RNA (16 S rRNA) sequencing. The NP microbial samples in healthy children were divided into two groups, which were dominated by either Staphylococcus or mixed microbial components. The respiratory microbiota in pneumonia patients harbored a lower microbial diversity compared to healthy children, and both the NP and OP microbiota of patients differed significantly from that of healthy children. Hospitalized MPP children with a higher abundance of Mycoplasma in the BAL fluid (BALF) microbiota tended to suffer longer hospitalization lengths and higher peak fevers and serum C-reactive protein levels. Concordance analysis explained the succession of imbalanced NP microbiota to the OP and lung in diseased children. However, the association of the abundance of Mycoplasma in BALF microbiota with that in NP or OP microbiota varied among individuals, which suggested the sensitivity of BALF in MPP diagnostics, mirroring MPP severity.

Efficacy of bronchoalveolar lavage and its influence factors in the treatment of Mycoplasma pneumoniae pneumonia with atelectasis

Objective: To investigate the efficacy of bronchoalveolar lavage (BAL) and its influence factors in the treatment of Mycoplasma pneumoniae pneumonia (MPP) with atelectasis. Methods: A retrospective case control study was performed on hospitalized MPP patients with atelectasis and received BAL in the Department of Pulmonology, Children's Hospital Zhejiang University School of Medicine from January 1, 2015 to July 31, 2017. Fever relieved in 48 hours and chest imaging improved in one week after BAL were considered effective. Clinical data, including age, sex, blood routine tests, lactate dehydrogenase (LDH), cytokines, complications, fever duration before BAL, course of disease before BAL, sputum plug, atelectasis area and its CT values of atelectasis site were collected. Student's t test, Mann-Whitney U test, or chi square test were used. Results: (1) A total of 163 patients were enrolled, including 69 boys and 94 girls, with the ratio of 1∶1.36. Their ages ranged from 6 months to 12.6 years. (2) On the day of bronchoscope, 113 patients still had fever. They were divided into effective group (n=66) and ineffective group (n=47) according to whether fever was relieved in 48 hours after BAL. The effective group were found to have less sputum plug compared with the ineffective group (33% (22/66) vs. 57% (27/47), χ(2)=6.499, P=0.011). The other factors such as sex, age, fever duration before BAL, course of disease before BAL, C reactive protein (CRP), LDH, IL-2, IL-4, IL-6, IL-10, TNF, IFN-γ, atelectasis area and CT value showed no significant difference between the two groups (all P>0.05). (3)A total of 122 cases had chest imaging after BAL. According to chest imaging improvement, they were divided into effective group (n=81) and ineffective group (n=41). The effective group showed lower CT value ((58±9) vs. (63±8) HU, t=-2.436, P=0.017), IL-6 and IL-10 (M(Q(1), Q(3))) (21.0 (1.9, 48.4) vs. 36.4(21.8, 93.6), 4.9 (3.7, 9.6) vs. 7.7 (4.4, 12.0) ng/L, Z=-2.387,-2.009, P=0.017, 0.045). Sex, age, fever duration before BAL, course of disease before BAL, CRP, LDH, IL-2, IL-4, TNF, IFN-γ, atelectasis area showed no significant differences between the two groups (all P>0.05). (4) Patients were divided into sputum plug group (57 cases) and non sputum plug group (106 cases) according to bronchoscopic findings. The sputum plug group showed higher LDH, CRP, IL-6, IFN-γ, incidence of pleural effusion and extrapulmonary complications (585(433, 833) vs. 369 (312, 588) U/L, 42 (19, 103) vs. 25 (12, 45) mg/L, 38.8 (22.1, 71.3) vs. 20.7 (9.2, 48.3) ng/L, 33.1 (13.5, 89.3) vs. 12.7 (6.5, 33.6) ng/L, 73.7% (42/57) vs. 52.8% (56/106), 40.4% (23/57) vs. 17.0% (18/106)), with statistically significant differences (Z=-4.865,-3.435,-3.098,-3.704, χ(2)= 0.010, 0.001, all P<0.01) . Additionally, fewer patients showed fever relief within 48 hours after BAL in the cases with sputum plug cases compared those without sputum plug (44.9% (22/49) vs. 68.8% (44/64), χ(2)= 0.011, P=0.009). Fewer patients showed chest imaging improvement within one week after BAL in the cases with sputum plug compared with those without sputum plug, but did not show significant difference (56.5% (26/46) vs. 72.4% (55/76), χ(2)=0.073, P=0.056). Conclusions: BAL has some therapeutic effect on fever or atelectasis in MPP children complicated with atelectasis. Chest imaging improvement or fever relief may be hampered by sputum plug, increased IL-6 or IL-10.

Interleukin 17A as a good predictor of the severity of Mycoplasma pneumoniae pneumonia in children

Early distinction between severe Mycoplasma pneumoniae pneumonia (MPP) and mild MPP is still difficult. The aim of this study was to analyze cytokines in bronchoalveolar lavage fluid (BALF) and explore predicting factors of severe MPP in children. Retrospective analysis was performed on 150 children with MPP or bronchial foreign body (FB) admitted in our hospital. The mRNA levels of IL17A were found significantly lower in severe MPP group comparing with mild MPP group or FB group. However, no significant difference was found in the levels of IL4, IL10 or interferon beta1 (IFNβ1) between the two groups. Receiver operator characteristic (ROC) curve analysis showed that IL17A can be used to distinguish severe MPP from mild MPP. These results were confirmed in a validation cohort including 40 MPP children from another hospital. IL17A levels were correlated with some clinical characters, such as refractoriness and pleural effusion. Lower IL17A levels were more likely to be found in refractory MPP children or in MPP children with pleural effusion. Moreover, the protein levels of IL17A in BALF were also found greatly decreased in children with severe MPP. Thus, decreased IL17A levels in BALF may be a valuable biomarker to identify severe MPP in children.

Evaluation of variation in coagulation among children with Mycoplasma pneumoniae pneumonia: a case-control study.

ObjectiveAcute organ embolism in children with Mycoplasma pneumoniae pneumonia (MPP) has been reported, but changes in coagulation are unclear. This study aimed to investigate changes in coagulation in children with MPP.MethodsA total of 185 children with MMP (cases) and 117 healthy children (controls) were recruited. We measured prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), and plasma fibrinogen (FIB) and D-dimer levels.ResultsPlasma FIB (3.39 ± 0.96 g/L vs 2.93 ± 0.6 6g/L, t = 4.50) and D-dimer (326.45 ± 95.62mg/L vs 263.93 ± 103.32mg/L, t=5.36) in MPP children were higher than controls and PT (9.54 ± 4.97S vs 11.48 ± 5.96S, t=3.05) and APTT (31.41 ± 12.01S vs 38.38 ± 11.72S, t=4.95) were shorter than controls. FIB, D-dimer, PT, and APTT were not different between the high IgM-titre and low-titre groups. The areas under the receiver operating characteristic curves in cases and controls for plasma FIB and D-dimer levels were 0.654 (95% confidence interval [CI], 0.593–0.716, P = 0.031) and 0.682 (95% CI, 0.619–0.744, P = 0.032), respectively.ConclusionsChildren with MPP have a higher risk of blood coagulation and thrombosis. Controlling these problems should be considered as soon as possible.

Clinical characteristics and the levels of interleukin-17 in Mycoplasma pneumoniae pneumonia children with atopic sensitization

Objective To explore the clinical characteristics and the levels of interleukin-17 (IL-17) in Mycoplasma pneumoniae (MP) pneumonia patients with atopic sensitization. Methods One hundred and sixty-two patients with MP pneumonia were hospitalized at the Department of Pediatrics, Tianjin Nankai Hospital from October 2015 to December 2016.All children with MP pneumonia were evaluated and divided into 2 groups: the atopic group (atopic MP pneumonia children, n=50) and the non-atopic group (non-atopic MP pneumonia children, n=112). Furthermore, 30 healthy children were also included in this study as healthy control group at the Department of Pedia-trics, Tianjin Nankai Hospital at the same time.The clinical characteristics and laboratory data of MP pneumonia patients of 2 groups were recorded and analyzed.The levels of serum IL-17 of MP pneumonia patients were measured by using enzyme-linked immunosorbent assays. Results Children with atopic MP pneumonia had more severe pneumonia.At the same time, the number of cases of oxygen therapy and glucocorticoid treatment, the duration of glucocorticoid treatment and the history of previous asthma in the atopic group were higher than those in the non-atopic group, and there was statistical difference between 2 groups(all P<0.05). The level of serum total immunoglobulin E in the atopic group [230.5(120.8, 421.5) IU/mL] was higher than that in the non-atopic group [79.9(46.1, 125.3) IU/mL], and the level of serum lactate dehydrogenase(LDH)in the atopic group [(319.3±118.9) IU/L] was higher than that in the non-atopic group [(255.5±66.6) IU/L], and there were statistical differences between 2 groups( all P<0.01). The levels of serum IL-17 in the healthy control group, atopic group and non-atopic group were(60.2±15.7) ng/L, (382.2±181.7) ng/L and(532.3±169.1) ng/L, respectively, and there were statistical differences among the 3 groups(F=105.668, P=0.000). Whereas, the level of serum IL-17 in the atopic group was lower than that in the non-atopic group, there was statistical difference between 2 groups(t=-3.861, P<0.01). Conclusion Atopy may cause adverse effects on the childhood MP pneumonia.It was likely to be relevant to low levels of IL-17. Key words: Mycoplasma pneumoniae pneumonia; Atopy; Interleukin-17

The level changes and clinical value of serum nerve growth factor and interleukin-15 in children with mycoplasma pneumoniae pneumonia

Objective To investigate the level changes and clinical value of serum nerve growth factor(NGF)and interleukin-15(IL-15)in children with mycoplasma pneumoniae pneumonia. Methods A retrospective study was performed on 90 patients with mycoplasma pneumoniae pneumonia(MPP)who were admitted from July 2014 to April 2015.At the same time, another 90 medical healthy children were selected as the control group in the same period.The serum NGF, IL-15 level changes.The serum NGF and IL-15 level changes in different onset age children with MPP and healthy children, and in critically ill children and children with mild acute phase were compared. Results Acute onset of nerve growth factor in serum and recovery period, the NGF and IL-15 were higher than those in the control group, and the difference was statistically significant(P<0.05); nerve growth factor in serum of children with acute exacerbation, NGF and IL-15 level were significantly higher than those of children in the recovery period, and the difference was statistically significant(P<0.05); in group of children with severe acute exacerbation, serum NGF and IL-15 level were significantly higher than those in children with mild group, and the difference was statistically significant(P<0.05); in group of children with severe recovery of nerve growth factor, the serum NGF, IL-15 levels were significantly higher than those in children with mild group, and the difference was statistically significant(P<0.05). Conclusion Serum NGF and IL-15 are checking sensitive index in MPP children, which can be used to evaluate the disease severity in MPP children, it is worth clinical promotion. Key words: Pneumonia; Mycoplasma pneumonia; Interleukin-15; Nerve growth factor

Transcriptome analysis of bronchoalveolar lavage fluid from children with severe Mycoplasma pneumoniae pneumonia reveals novel gene expression and immunodeficiency

BackgroundA growing number of severe Mycoplasma pneumoniae pneumonia (MPP) cases have been reported recently. However, the pathogenesis of severe MPP is not clear. In the current study, transcriptome sequencing was used to identify gene expression and alternative splicing profiles to provide insights into the pathogenesis of severe MPP.MethodsRNAs of bronchoalveolar lavage fluid (BALF) samples from three severe MPP children and three mild MPP children were analyzed respectively by deep sequencing followed by computational annotation and quantification.ResultsThe gene expression analysis revealed 14 up-regulated and 34 down-regulated genes in severe MPP children comparing to mild MPP children. The top 10 most up-regulated genes were IGHV1-69, CH17-472G23.1, ATP1B2, FCER2, MUC21, IL13, FCRLB, CLEC5A, FAM124A, and INHBA. The top 10 most down-regulated genes were OSTN-AS1, IL22RA2, COL3A1, C1orf141, IGKV2-29, RP11-731F5.2, IGHV4-4, KIRREL, DNASE1L3, and COL6A2. Clustering analysis revealed similar expression pattern of CLEC5A, IL13, FCER2, and FLT1. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses revealed changes related to primary immunodeficiency in severe MPP children comparing to mild MPP children; the pathway involves CD19, TNFRSF13C, CD79A, and AICDA genes. Among the differentially expressed genes, significant alternative splicing events were found in FCER2 and FCRLA.ConclusionsThe current study on RNA sequencing provides novel insights into the pathogenesis of severe MPP in terms of gene expression and alternative splicing. The up-regulation of IL13, FCER2, FLT1, and CLEC5A and the down-regulation of CD79A, AICDA, CD19, and TNFRSF13C may contribute to the pathogenesis of severe MPP. The differential expressions of FCER2 and FCRLA could be due to their alternative splicing.

Relationships between Th1/Th2 cytokine profiles and chest radiographic manifestations in childhood Mycoplasma pneumoniae pneumonia.

BackgroundMycoplasma pneumoniae pneumonia (MPP) is one of the most common childhood community-acquired pneumonias, and the chest radiograph usually shows bronchial pneumonia, segmental/lobar pneumonia, or segmental/lobar pneumonia with pleural effusion. The imbalance of Th1/Th2 function after Mycoplasma pneumoniae infection is an important immunological mechanism of MPP. In this study, we aimed to evaluate the correlations between Th1/Th2 cytokine profiles and chest radiographic manifestations in MPP children.Patients and methodsA total of 87 children with MPP were retrospectively reviewed in this study. According to the chest radiographic manifestations, they were divided into the following three groups: bronchial MPP group, segmental/lobar MPP group, and segmental/lobar MPP with pleural effusion group. Clinical features and changes in Th1/Th2 cytokines were further analyzed.ResultsThe incidence of tachypnea and cyanosis was higher in children with segmental/lobar MPP with pleural effusion than in those with segmental/lobar or bronchial MPP. The peak body temperature of segmental/lobar MPP was higher than that of bronchial MPP, and the duration of fever and hospitalization was positively correlated with the severity of MPP. MPP children’s chest radiograph showed a relationship with the changes in Th1/Th2 cytokines. Serum interleukin-4, interleukin-10 (IL-10), interferon-γ, and tumor necrosis factor-α (TNF-α) of segmental/lobar MPP were significantly higher than those of bronchial MPP, and serum IL-10 (cutoff value: 27.25 pg/mL) can be used as a diagnostic predictor for segmental/lobar MPP. Serum TNF-α and interleukin-6 of segmental/lobar MPP with pleural effusion were significantly higher than those of segmental/lobar MPP without pleural effusion. Serum TNF-α (cutoff value: 60.25 pg/mL) can be used as a diagnostic predictor for segmental/lobar MPP with pleural effusion.ConclusionThere were significant correlations between Th1/Th2 cytokine profiles and chest radiographic manifestations in MPP children. Serum IL-10 and TNF-α can be used as an optimal predictor for segmental/lobar MPP and segmental/lobar MPP with pleural effusion, respectively.

Pathogenesis and association of Mycoplasma pneumoniae infection with cardiac and hepatic damage.

The aim of this study was to investigate the pathogenesis of Mycoplasma pneumoniae (MP) infection and its association with cardiac and hepatic damage. Between March 2013 and March 2014, 59 children with MP pneumonia (MPP) and 30 healthy children were enrolled. Serum titers of TLR4, T cell immunoglobulin and mucin-domain (TIM) 3, IL-10, TNF-α, and IFN-γ were measured both in children with MPP and healthy children. Additionally, MP-specific antibody titer and creatine kinase-MB (CK-MB), and alanine transaminase (ALT) titers were measured in patients with MPP. There were significant differences between the MPP patients and healthy controls in titers of TIM1 (P < 0.01), TLR2 (P = 0.028), TLR4 (P = 0.019), IL-10 (P < 0.01), TNF-α (P < 0.01) and IFN-γ (P < 0.01); however, no significant difference was found in TIM3 titers (P = 0.8181). TIM1 was correlated with CK-MB (P = 0.025), whereas both TIM1 and TLR2 titers were correlated with MP-specific antibody titers (P < 0.001; P = 0.003, respectively). Additionally, there were correlations between ALT, TIM3, and TLR2 titers (P = 0.025; P = 0.037, respectively). The titers of TIM1 were significantly higher in patients with cardiac damage (P = 0.007) than in those without it, whereas the titers of TLR2 were significantly higher in patients with hepatic damage (P = 0.026) than in those without it. TLR2, TLR4 and TIM1 may be involved in the process of MP infection. Additionally, TLR2, TLR4, TIM1 and TIM3 may play particular roles in the pathogenesis of MPP-associated cardiac and hepatic damage.

The changes of serum cytokines in children with mycoplasma pneumoniae pneumonia

Objective To investigate the changes of serum cytokines in children with mycoplasma pneumoniae pneumonia (MPP).Methods A total of 239 children with MPP hospitalized in our department from Jan 2008 to Dec 2009 served as MPP group,which were redivided into mild MPP group (n =152) and severe MPP group ( n =87 ).Two hundred and sixty-three acute bronchopneumonia children without MPP infection served as non-MPP group.Fifty cases who would undergo hernia and phimosis elective surgery in pediatric surgery department served as control group.All children with pneumonia were detected mycoplasma pneumoniae antibodies and cytokines (TNF-α,IFN-γ,IL-1β,IL-4,IL-6) of serum in the first day of hospitalization and recovery period.Children in control group were detected the level of cytokines only once.Results Serum levels of TNF-α,IL-1β,IL-6 in MPP group and non-MPP group were higher than those in control group ( P ＜ 0.01 ).No significant differences of IFN-γ and IL-4 levels were found among three groups ( P ＞ 0.05 ).Compared with non-MPP group,the levels of IFN-γ,IL-1β and IFN-γ/IL-4 were higher in MPP group ( P ＜ 0.01 ).The levels of TNF-α,IL- 1β,IL-6,and IFN-γ/IL-4 were significantly decreased in the recovery period of MPP (P ＜0.001,P ＜ 0.05 ).The levels of TNF-α,IL-1β and IFN-γ/IL-4 in severe MPP children were higher than those in mild MPP children ( P ＜ 0.01 ).Conclusion The immunologic function of MPP children is unbalanced.The serum levels of TNF-α,IL-1β,IL-6,and IFN-γ/IL-4 are correlated with severity of MPP,which help to evaluate the state of MPP. Key words: Mycoplasma pneumoniae pneumonia; Tumor necrosis factor-α; Interleukin-4; Interferonγ; Interleukin-6; Interleukin-1β; Children

An outbreak of mycoplasma pneumoniae pneumonia in a kindergarten

To study the epidemiological and clinical features of the mycoplasma pneumoniae pneumonia (MPP) that occurred in a single class of a kindergarten in Beijing in July 2006. The environment and the attendance record of the kindergarten from the beginning of August 2005 to the end of July 2006 were investigated, and the sick status of the children absent for illness were interviewed by face to face or telephone through their parents. The disease data of the in-patient children with MPP were collected through questionnaires and analyzed. Serological screening for MP was performed with the Serodia Myco II gelatin particle agglutination test (Fujirebio, Japan). In mid-July 2006, in a day-care kindergarten with 3 grade classes, 3 out of 25 six-year-old children in the top class were hospitalized within 4 days and diagnosed as MPP. A total of 8 children had the symptoms of fever and cough during late May and mid-July in 2006, 5 children conduct chest radiographs and all had pneumonia, all these five children showed antibody positive for MP, 3 of them showed a more than 4-fold increase in antibody titer to MP in serum. There were no pneumoniae cases in the other two classes during the same period, and no pneumoniae cases happened among the teachers in the top class and the parents of the 5 pneumoniae children. All the children were moved to this classroom temporarily with limited ventilation and sunshine in March 2006. After improvement of the ventilation in the classroom, no additional pneumoniae cases occurred in the top class till the early September 2006. The 5 MPP children showed neither sneeze and nasal obstruction, nor skin rash, earache and any other extrapulmonary complication, and their peripheral white blood cell count was in the normal range (3.9 - 7.7) x 10(9). The MPP outbreak in a kindergarten was caused by poor ventilation of the temporary classroom. MP infection in children is liable to cause pneumonia.