肺炎支原体荧光定量聚合酶链反应检测在儿童肺炎支原体肺炎中的诊断意义

Diagnostic Value of Fluorescent Quantitative Polymerase Chain Reaction for Mycoplasma Pneumoniae Pneumoniae in Children with Mycoplasma Pneumoniae Pneumonia

目的探讨肺炎支原体(MP)荧光定量PCR检测在儿童MP肺炎(MPP)中的诊断价值。方法选择2008年6月-2009年1月住院的肺炎患儿153例,同期住院的非呼吸道感染患儿30例作为对照组。入选患儿均留取呼吸道分泌物(鼻咽深部分泌物、痰、肺泡灌洗液或咽拭子)和血清标本,部分患儿留取双份血清。采用MP荧光定量PCR法检测其呼吸道分泌物标本中MP DNA水平,用ELISA法和被动凝集法分别检测患儿血清MP-IgM抗体及MP抗体滴度。结果入选肺炎患儿中,MP抗体检测阳性(MPP)123例,双份血清MP检测阴性肺炎(非MPP)30例。MPP组:PCR阳性114例,PCR定量结果MP DNA水平为1.20×106～3.66×1010基因拷贝/L。非MPP组:PCR阳性2例,MP DNA水平为(1.08～3.02)×107基因拷贝/L。对照组:PCR结果均阴性。MPP患儿病程第1-2周,单份血清MP-IgM检测的敏感度仅为66.7%～83.9%,而定量PCR的敏感度为92.7%,特异度为93.3%;病程第3周后,单份血MP-IgM检测的敏感度上升为90.9%～100%。MPP组患儿入院时病程、住院时间及热程均显著长于非MPP组患儿,其临床表现无特异性。结论荧光定量PCR法较血清学方法更适用于MPP的早期快速诊断,2种方法结合既有利于早期诊断,又可提高诊断的准确性。

Objective To evaluate the diagnostic value of fluorescent quantitative polymerase chain reaction（PCR） for Mycoplasma pneumoniae （MP） in children with MP pneumonia （MPP）. Methods From Jun. 2008 to Jan. 2009,153 cases hospitalized with pneumonia were enrolled,and 30 cases without respiratory infection were enrolled as control group. Their respiratory secretion （ including nasopharyngeal secretion,sputum,bronchialalveolar lavage fluid or pharyngeal swab） samples were collected for fluorescent quantitative PCR for MP. And their single or paired serums were collected for specific MP antibody detention. Results There were 123 cases confirmed with MPP by serology ,among whom 114 cases were MP PCR positive. The quantitation of MP DNA was among 1.20 × 10^6 - 3.66 ×10^10 gene copys/L. There were 30 eases with pneumonia negative with MP by the paired serum serology,among whom 2 cases were M P PC R positive,and the quantitation of MP DNA was （ 1.08 - 3.02） × 10^7gene eopys/L. All cases of control group were MP PCR negative. During the first and second weeks of the MPP onset,the sensitivity of MP - IgM from the first single blood samples were 66.7% and 83.9% ,respectively. While the sensitivity and specificity of MP PCR were 92.7% and 93.3% ,respectively. From the third week of the disease onset,the sensitivity of MP - IgM from the first single blood samples increased to 90.9% - 100%. The clinical manifestations of MPP were nonspecific. Conclusions PCR is superior to serology for early diagnosis ou MP infection. Combination of the 2 methods may be helpful to early and accurate diagnosis on MP infection.