Dissertation > Medicine, health > Internal Medicine > Respiratory system and chest diseases > Pulmonary disease > Pneumonia

Clinical Analysis of Mycoplasma Pneumoniae and Its Role in Immunological Pathology

Author GaoWei
Tutor LiuYunDe
School Tianjin Medical University
Course Clinical Laboratory Science
Keywords Mycoplasma pneumoniae Macrolide antibiotics Resistance gene Cytokines
CLC R563.1
Type Master's thesis
Year 2011
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Purpose of Mycoplasma pneumoniae (Mycoplasma pneumoniae, MP), the human mycoplasma pneumonia pathogens, infection performance in recent years for various pulmonary complications, refractory cases of pneumonia increased its specific pathogenic mechanism is unclear. The drug of choice for the clinical treatment of MP infection is a macrolide antibiotic, however MP23SrRNA gene mutations cause macrolide resistance reported at home and abroad, MP resistance gene mutants growing, China's Beijing area MP resistance gene detection rate as high as 90%. However, in vitro drug sensitivity test results can not be representative of the true treatment effect of the drug in the body are difficult to culture, but also due to the separation of Mycoplasma pneumoniae MP vitro susceptibility testing of macrolides is not a clinical routine testing project. Scholars have established a variety of drug-resistant mutation detection method, resistance testing can be applied to clinical Mycoplasma pneumoniae. This study was designed through the analysis of the macrolide antibiotics MP resistance gene mutants clinical treatment effect, the evaluation of the clinical significance of the MP-resistance gene detection by MP infection rat model to investigate the immunological MP pathogenic mechanisms to Mycoplasma pneumoniae infection provide the basis for clinical treatment. Clinical analysis methods 1.MP infection. Select to meet the inclusion criteria, 66 cases of suspected mycoplasma pneumonia in hospitalized patients, 33 males and 33 females, collected lavage fluid of patients with sputum and throat swab specimens, PCR method for the MP DNA detection and contains the mutation site 933bp fragment amplification, the amplified fragment of the nucleic acid sequence determination. The medical records of patient days of fever, days of hospitalization, the use of hormones and the occurrence of complications as the analysis of indicators, to compare the resistance gene in mutant and non-mutant analysis of macrolide antibiotics MP resistance gene mutation strains of clinical effect. Immunological pathogenic mechanisms 2.MP. 45 rats were randomly divided into infection group 25, control group 20 group of infection in sterile console for four days in a row nasal inoculation 100μ1 (106CFU/ml) MP control group under the same conditions for four consecutive days nasal inoculation 100μ1MP liquid medium. 1,3,5,8,10 days after completion of the vaccination were sacrificed at the infected group and the control group of rats, collected lavage fluid and lung tissue. Quantitative PCR methods BALF MP DNA content ELISA method for detection of Th1/Th2 cytokines in bronchoalveolar lavage fluid, and lung histopathology score after HE staining of rat lung tissue. Analysis of rats infected MP lavage fluid of Th1 and Th2 cytokines dynamic changes, the interaction between the study the MP infected with the immune system, understanding its pathogenic mechanism. Results as the 1.66 patients the 46 patients MPDNA positive, 20 cases negative lavage fluid, sputum, throat swab MP separation rate were 69.7%, 18.2%, 6.1%, bronchoalveolar lavage fluid separation rate in sputum liquid and throat swabs (P lt; 0.01); of 46 copies MPDNA samples 31 copies in existence resistant gene mutations, mutation rate was 67.4% (31/46), both 2063A → G mutation did not find other sites mutation; resistance gene mutants (macrolide-resistant, MR) and non-mutant (macrolide-by susceptible, MS) patient days of fever, days of hospitalization, hormone use and complications no statistically significant difference (P value for 0.459,0.632,0.793,0.575). The third day of inflammation in the infected rats modeling to achieve the most weight, lung pathology score was 14.7 (maximum score of 16 points), the fifth day of inflammation score declined pathological scores of 9.7 points, the control group had no significant pathological changes, quantitative PCR infected group in the whole process could be detected to MP, and the MPDNA content is relatively stable compared with no statistically significant difference between the days; rats Thl cytokines IFN-γ increased after infection MP peak three days, and IFN-γ levels and lung histopathology score was positively correlated (R = 0.900, P lt; 0.05), while the Th2 cytokines IL-4 did not change significantly after infection. Conclusion The results of this study show that: MP macrolide resistance gene mutation detection rate of 63.4%, are 2063A → G mutation; MP resistance gene mutant and non-mutant patient days of fever, days of hospitalization, hormone use the differences are in the situation and complications, macrolide antibiotics, the therapeutic effect of the mutant MP resistance genes may be related to the inhibition of the the immunomodulatory activity related to the bacterial protein synthesis, and therefore recommended clinical do not have to regularly MP-resistant gene detection ; MP resistance does not result in patients with the extension of the course and complications increased, suggesting itself carrying resistance genes may not be the main cause refractory MP pneumonia, the specific mechanism needs further research; promote inflammation MP infection in rats Thl class elevated cytokine concentration and lung pathology score, sky anti-inflammatory effects of Th2 cytokines showed no significant change, the cytokine expression rat Thl/Th2 class imbalance, which revealed the MP caused immunological mechanisms of disease, but also prompt us for the treatment of MP infection from pathogenic immunological mechanisms aspects immunomodulatory agents for treatment.

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