Mycoplasma hyopneumoniae is the pathogen causing swine mycoplasmal pneumonia. The lack of well-established animal models of M. hyopneumoniae infection has delayed the progress of M. hyopneumoniae-related anti-infection immunity studies. This paper reviews the inflammatory response, the recognition of M. hyopneumoniae by the innate immune system, and the role of innate immune cells, complement system, antimicrobial peptides, autophagy, and apoptosis in M. hyopneumoniae infection. The aim was to elucidate the important roles played by the components of the innate immune system in the control of M. hyopneumoniae infection, and prospect key research directions of innate immune response of M. hyopneumoniae infection in the future.
Animals ; Swine ; Mycoplasma hyopneumoniae ; Pneumonia of Swine, Mycoplasmal ; Immunity, Innate

OBJECTIVES: To investigate the risk factors for performing bronchoalveolar lavage (BAL) in children with Mycoplasma pneumoniae pneumonia (MPP) and pulmonary consolidation, and to construct a predictive model for performing BAL in these children. METHODS: A retrospective analysis was performed for the clinical data of 202 children with MPP who were hospitalized in the Department of Pediatrics, Changzhou No. 2 People's Hospital Affiliated to Nanjing Medical University, from August 2019 to September 2022. According to whether BAL was performed, they were divided into BAL group with 100 children and non-BAL group with 102 children. A multivariate logistic regression analysis was used to identify the risk factors for performing BAL in MPP children with pulmonary consolidation. Rstudio software (R4.2.3) was used to establish a predictive model for performing BAL, and the receiver operator characteristic (ROC) curve, C-index, and calibration curve were used to assess the predictive performance of the model. RESULTS: The multivariate logistic regression analysis demonstrated that the fever duration, C-reactive protein levels, D-dimer levels, and presence of pleural effusion were risk factors for performing BAL in MPP children with pulmonary consolidation (P<0.05). A nomogram predictive model was established based on the results of the multivariate logistic regression analysis. In the training set, this model had an area under the ROC curve of 0.915 (95%CI: 0.827-0.938), with a sensitivity of 0.826 and a specificity of 0.875, while in the validation set, it had an area under the ROC curve of 0.983 (95%CI: 0.912-0.996), with a sensitivity of 0.879 and a specificity of 1.000. The Bootstrap-corrected C-index was 0.952 (95%CI: 0.901-0.986), and the calibration curve demonstrated good consistency between the predicted probability of the model and the actual probability of occurrence. CONCLUSIONS The predictive model established in this study can be used to assess the likelihood of performing BAL in MPP children with pulmonary consolidation, based on factors such as fever duration, C-reactive protein levels, D-dimer levels, and the presence of pleural effusion. Additionally, the model demonstrates good predictive performance.
Child ; Humans ; Mycoplasma pneumoniae ; Retrospective Studies ; C-Reactive Protein/analysis* ; Pneumonia, Mycoplasma/diagnosis* ; Bronchoalveolar Lavage ; Pleural Effusion

Objective: To investigate the risk factors for airway mucus hypersecretion in childhood pneumonia infected by different pathogens. Method: A retrospective cohort included 968 children who were hospitalized for Mycoplasma pneumoniae pneumonia (MPP), respiratory syncytial virus (RSV) pneumonia, adenovirus pneumonia and underwent bronchoscopy in Respiratory Department of Children's Hospital of Chongqing Medical University from January 2019 to December 2021 was conducted. The children were divided into two groups distinguished by airway mucus secretion according to the airway mucus hypersecretion score which were scored according to the mucus secretion under the bronchoscope. The demographic characteristics, clinical characteristics, laboratory tests and disease severity of the two groups were compared. And the risk factors for the development of airway mucus hypersecretion in two groups were analyzed. Chi square test, Mann-Whithey U test and Fisher exact test were used to analyze the differences between the two groups, and multivariate Logistic regression was used to analyze the influencing factors. Result: There were 559 males and 409 females in the 968 children, with an age of 4.0 (1.4, 6.0) years. Among the 642 children with MPP, 185 cases were in the hypersecretion group and 457 cases were in the non-hypersecretion group. There were 41 cases in the hypersecretion group and 160 cases in the non-hypersecretion group of 201 children with RSV pneumonia. In the 125 children with adenovirus pneumonia, there were 39 cases in the hypersecretion group and 86 cases in the non-hypersecretion group. In these children, the age of children in the hypersecretion group was older than that in the non-hypersecretion group (6.0 (4.0, 7.0) vs. 5.0 (3.0, 7.0) years old, 1.5 (0.5, 3.6) vs. 0.8 (0.4, 1.6) years old, 2.0 (1.2, 4.5) vs. 1.3 (0.8, 2.0) years old, U=35 295.00, 2 492.00, 1 101.00, all P<0.05). Through multivariate Logistic regression analysis it found that increased risk of airway mucus hypersecretion was present in childhood MPP with increase in peripheral blood white blood cell count (OR=3.30, 95%CI 1.51-7.93, P=0.004) or increase in neutrophil ratio (OR=2.24, 95%CI 1.16-4.33, P=0.016) or decrease in lymphocyte count (OR=3.22, 95%CI 1.66-6.31, P<0.001) or decrease in serum albumin (OR=2.00, 95%CI 1.01-3.98, P=0.047). The risk of airway mucus hypersecretion was increased in children with RSV pneumonia combined with elevated peripheral blood eosinophils (OR=3.04, 95%CI 1.02-8.93, P=0.043). Meanwhile, airway mucus hypersecretion was associated with severe pneumonia (OR=2.46, 95%CI 1.03-6.15, P=0.047) in children with RSV pneumonia. Older age was associated with increased risk of airway mucus hypersecretion in children with adenovirus pneumonia (OR=1.02, 95%CI 1.00-1.04, P=0.026). In these children with occurrence of pulmonary rales, wheezes or sputum sounds (OR=3.65, 95%CI 1.22-12.64, P=0.028) had an increased risk of airway mucus hypersecretion. Neutrophils in bronchoalveolar lavage fluid (BALF) demonstrated higher ratio in hypersecretion group from children with MPP (0.65 (0.43, 0.81) vs. 0.59 (0.34, 0.76), U=24 507.00, P<0.01), while the proportion of macrophages in BALF was lower (0.10 (0.05, 0.20) vs. 0.12 (0.06, 0.24), U=33 043.00, P<0.05). Nucleated cell count and neutrophil ratio in BALF were higher in hypersecretion group of children with RSV pneumonia (1 210 (442, 2 100)×10⁶ vs. 490 (210, 1 510)×10⁶/L, 0.43 (0.26, 0.62) vs. 0.30 (0.13, 0.52), U=2 043.00, 2 064.00, all P<0.05). Conclusions: The increase in peripheral blood white blood cell count, neutrophil ratio and decrease in lymphocyte count, serum albumin in children with MPP is related to the development of airway mucus hypersecretion. In children with RSV pneumonia, the abnormal increase of eosinophils in peripheral blood has relationship with hypersecretion. The appearance of lung rale, wheezing, and sputum rale are associated with airway mucus hypersecretion in children with adenovirus pneumonia. In addition, local neutrophil infiltration in the respiratory tract is closely related to the occurrence of airway mucus hypersecretion caused by Mycoplasma pneumoniae and RSV infection.
Child ; Male ; Female ; Humans ; Infant ; Child, Preschool ; Retrospective Studies ; Respiratory Sounds ; Pneumonia, Mycoplasma ; Lung ; Respiratory Syncytial Virus Infections ; Mucus ; Pneumonia, Viral ; Risk Factors

OBJECTIVES: To investigate the distribution characteristics of non-bacterial pathogens in community-acquired pneumonia (CAP) in children. METHODS: A total of 1 788 CAP children admitted to Shenyang Children's Hospital from December 2021 to November 2022 were selected. Multiple RT-PCR and capillary electrophoresis were used to detect 10 viral pathogens and 2 atypical pathogens, and serum antibodies of Chlamydial pneumoniae (Ch) and Mycoplasma pneumoniae (MP) were detected. The distribution characteristics of different pathogens were analyzed. RESULTS: Among the 1 788 CAP children, 1 295 children were pathogen-positive, with a positive rate of 72.43% (1 295/1 788), including a viral pathogen positive rate of 59.68% (1 067/1 788) and an atypical pathogen positive rate of 22.04% (394/1 788). The positive rates from high to low were MP, respiratory syncytial virus (RSV), influenza B virus (IVB), human metapneumovirus (HMPV), human rhinovirus (HRV), human parainfluenza virus (HPIV), influenza A virus (IVA), bocavirus (BoV), human adenovirus (HADV), Ch, and human coronavirus (HCOV). RSV and MP were the main pathogens in spring; MP had the highest positive rate in summer, followed by IVA; HMPV had the highest positive rate in autumn; IVB and RSV were the main pathogens in winter. The positive rate of MP in girls was higher than that in boys (P<0.05), and there were no significant differences in other pathogens between genders (P>0.05). The positivity rates of certain pathogens differed among age groups (P<0.05): the positivity rate of MP was highest in the >6 year-old group; the positivity rates of RSV and Ch were highest in the <1 year-old group; the positivity rates of HPIV and IVB were highest in the 1 to <3 year-old group. RSV, MP, HRV, and HMPV were the main pathogens in children with severe pneumonia, while MP was the primary pathogen in children with lobar pneumonia, and MP, IVB, HMPV, RSV, and HRV were the top 5 pathogens in acute bronchopneumonia. CONCLUSIONS MP, RSV, IVB, HMPV, and HRV are the main pathogens of CAP in children, and there are certain differences in the positive rates of respiratory pathogens among children of different ages, genders, and seasons.
Humans ; Child ; Female ; Male ; Infant ; Child, Preschool ; Pneumonia ; Respiratory Syncytial Virus, Human ; Antibodies ; Community-Acquired Infections ; Hospitalization ; Influenza B virus ; Mycoplasma pneumoniae

Humans ; Pneumonia, Mycoplasma/diagnosis*

Objective: To investigate the predictive factors for bronchitis obliterans in refractory Mycoplasma pneumoniae pneumonia (RMPP). Methods: A restrospective case summary was conducted 230 patients with RMPP admitted to the Department of No.2 Respiratory Medicine of Beijing Children's Hospital, Capital Medical University from January 2013 to June 2017 were recruited. Clinical data, laboratory results, imaging results and follow-up data were collected. Based on bronchoscopy and imaging findings 1 year after discharge, all patients were divided into two groups: one group had sequelae of bronchitis obliterans (sequelae group) and the other group had not bronchitis obliterans (control group), independent sample t-test and nonparametric test were used to compare the differences in clinical features between the two groups. Receiver operating characteristic (ROC) curve to explore the predictive value of Bronchitis Obliterans in RMPP. Results: Among 230 RMPP children, there were 115 males and 115 females, 95 cases had sequelae group, the age of disease onset was (7.1±2.8) years;135 cases had control group, the age of disease onset was (6.8±2.7) years. The duration of fever, C-reative protein (CRP) and lactate dehydrogenase (LDH) levels, the proportion of ≥2/3 lobe consolidation, pleural effusion and the proportion of airway mucus plug and mucosal necrosis were longer or higher in the sequelae group than those in the control group ((17±9) vs. (12±3) d, (193±59) vs. (98±42) mg/L,730 (660, 814) vs. 486 (452, 522) U/L, 89 cases (93.7%) vs. 73 cases (54.1%), 73 cases (76.8%) vs.59 cases (43.7%), 81 cases (85.3%) vs. 20 cases (14.8%), 67 cases (70.5%) vs. 9 cases (6.7%), t=5.76, 13.35, Z=-6.41, χ²=14.64, 25.04, 22.85, 102.78, all P<0.001). Multivariate Logistic regression analysis showed that the duration of fever ≥10 days (OR=1.200, 95%CI 1.014-1.419), CRP levels increased (OR=1.033, 95%CI 1.022-1.044) and LDH levels increased (OR=1.001, 95%CI 1.000-1.003) were the risk factors for sequelae of bronchitis obliterans in RMPP. ROC curve analysis showed that CRP 137 mg/L had a sensitivity of 82.1% and a specificity of 80.1%; LDH 471 U/L had a sensitivity of 62.7% and a specificity of 60.3% for predicting the development of bronchitis obliterans. Conclusions: The long duration of fever (≥10 d), CRP increase (≥137 mg/L) may be used to predict the occurrence of sequelae of bronchitis obliterans in RMPP. It is helpful for early recognition of risk children.
Child ; Male ; Female ; Humans ; Child, Preschool ; Mycoplasma pneumoniae ; Retrospective Studies ; Pneumonia, Mycoplasma/complications* ; Disease Progression ; L-Lactate Dehydrogenase ; Fever

Child ; Humans ; Pneumonia, Mycoplasma/epidemiology* ; Macrolides/therapeutic use* ; Singapore/epidemiology* ; Child, Hospitalized ; Mycoplasma pneumoniae ; Anti-Bacterial Agents/therapeutic use* ; Drug Resistance, Bacterial ; Community-Acquired Infections/drug therapy*

Objective: To describe the clinical characteristics of Mycoplasma pneumoniae infection and analyze the factors associated with co-infections with other pathogens in children, and provide evidence for improvement of community acquired pneumonia (CAP) prevention and control in children. Methods: Based on the surveillance of hospitalized acute respiratory infections cases conducted in Soochow University Affiliated Children's Hospital (SCH), the CAP cases aged <16 years hospitalized in SCH between 2018 and 2021 were screened. The pathogenic test results of the cases were obtained through the laboratory information system, and their basic information, underlying conditions, and clinical characteristics were collected using a standardized questionnaire. The differences in clinical characteristics between M. pneumoniae infection and bacterial or viral infection and the effect of the co-infection of M. pneumoniae with other pathogens on clinical severity in the cases were analyzed; logistic regression was used to analyze the factors associated with the co-infections with other pathogens. Results: A total of 8 274 hospitalized CAP cases met the inclusion criteria. Among them, 2 184 were positive for M. pneumoniae (26.4%). The M. pneumoniae positivity rate increased with age (P<0.001), and it was higher in girls (P<0.001) and in summer and autumn (P<0.001). There were statistically significant differences in the incidence of wheezing, shortness of breath, wheezing sounds and visible lamellar faint shadow on chest radiographs, as well as fever and hospitalization days among M. pneumoniae, bacterial, and viral infection cases (all P<0.05). In the cases aged <60 months years, co-infection cases had higher rates of wheezing, gurgling with sputum and stridor; and in the cases aged ≥60 months, co-infection cases had a higher rate of shortness of breath (all P<0.05). Multifactorial logistic regression analysis showed that being boys (aOR=1.38,95%CI:1.15-1.67), being aged <6 months (aOR=3.30,95%CI:2.25-4.89), 6-23 months (aOR=3.44,95%CI:2.63-4.51), 24-47 months (aOR=2.50,95%CI:1.90-3.30) and 48-71 months (aOR=1.77,95%CI:1.32-2.37), and history of respiratory infection within 3 months (aOR=1.28,95%CI:1.06-1.55) were factors associated with co-infections of M. pneumoniae with other pathogens. Conclusions: M. pneumoniae was the leading pathogen in children hospitalized due to CAP. M. pneumoniae infections could cause fever for longer days compared with bacterial or viral infections; M. pneumoniae was often co-detected with virus or bacteria. Being boys, being aged <72 months and history of respiratory infection within 3 months were associated factors for co-infections.
Bacteria ; Child ; Coinfection/epidemiology* ; Community-Acquired Infections/epidemiology* ; Dyspnea ; Female ; Humans ; Male ; Mycoplasma pneumoniae ; Pneumonia, Mycoplasma/microbiology* ; Respiratory Sounds ; Respiratory Tract Infections/epidemiology* ; Virus Diseases

Objective: We investigated changes in the intestinal flora of children with Mycoplasma pneumoniae pneumonia (MPP). Methods: Between September 2019 and November 2019, stool samples from 14 children with MPP from The Fourth Hospital of Baotou city, Inner Mongolia Autonomous Region, were collected and divided into general treatment (AF) and probiotic (AFY) groups, according to the treatment of "combined Bifidobacterium, Lactobacillus, Enterococcus, and Bacillus cereus tablets live". High-throughput 16S rDNA sequencing was used to identify intestinal flora. Results: Intestinal flora abundance and diversity in children with MPP were decreased. Both Shannon and Simpson indices were lower in the AF group when compared with healthy controls ( P < 0.05). When compared with healthy controls, the proportion of Enterorhabdus was lower in the AF group, while the proportion of Lachnoclostridium was higher ( P < 0.05). The proportion of Bifidobacteria and Akkermansia was lower in the AFY group but Enterococcus, Lachnoclostridium, Roseburia, and Erysipelatoclostridium proportions were higher. The proportion of Escherichia coli- Shigella in the AFY group after treatment was decreased ( P < 0.05). Conclusions The intestinal flora of children with MPP is disturbed, manifested as decreased abundance and diversity, and decreased Bifidobacteria. Our probiotic mixture partly improved intestinal flora disorders.
Child ; DNA, Ribosomal ; Escherichia coli ; Gastrointestinal Microbiome ; Humans ; Mycoplasma pneumoniae ; Pneumonia, Mycoplasma ; Technology

OBJECTIVES: To study the value of autotaxin (an autocrine motility factor) level in serum and bronchoalveolar lavage fluid (BALF) in predicting refractory Mycoplasma pneumoniae pneumonia (RMPP) in children and its correlation with interleukin-6 (IL-6), interleukin-8 (IL-8), and C-reactive protein (CRP). METHODS: A retrospective analysis was performed on 238 children with Mycoplasma pneumoniae pneumonia who were admitted from January 2019 to December 2021. According to disease severity, they were divided into two groups: RMPP (n=82) and general Mycoplasma pneumoniae pneumonia (GMPP; n=156). The two groups were compared in terms of the levels of autotaxin, IL-6, IL-8, and CRP in serum and BALF to study the value of autotaxin level in serum and BALF in predicting RMPP in children, as well as the correlation of autotaxin level with IL-6, IL-8, and CRP in children with RMPP. RESULTS: Compared with the GMPP group, the RMPP group had significantly higher levels of autotaxin, IL-6, IL-8, and CRP in serum and BALF (P<0.05). For the children with RMPP, the levels of autotaxin, IL-6, IL-8, and CRP in serum and BALF in the acute stage were significantly higher than those in the convalescent stage (P<0.05). The receiver operating characteristic (ROC) curve showed that the level of autotaxin in serum and BALF had a good value in predicting RMPP in children, with an area under the curve of 0.874 (95%CI: 0.816-0.935) and 0.862 (95%CI: 0.802-0.924), respectively. The correlation analysis showed that the level of autotaxin in serum and BALF was positively correlated with IL-6, IL-8, and CRP levels (P<0.001). CONCLUSIONS The level of autotaxin in serum and BALF increases and is correlated with the degree of disease recovery and inflammatory cytokines in children with RMPP. Autotaxin can be used as a predictive indicator for RMPP in children.
C-Reactive Protein ; Child ; Cytokines ; Humans ; Interleukin-6 ; Interleukin-8 ; Mycoplasma pneumoniae ; Pneumonia, Mycoplasma/diagnosis* ; Retrospective Studies