肺炎支原体肺炎患儿混合感染的研究

Mixed infections in children with Mycoplasma pneumonial pneumonia

目的 了解肺炎支原体（MP）肺炎儿童的混合感染情况.方法 201例诊断MP肺炎住院患儿进行痰细菌培养、呼吸道病毒抗原及血清肺炎衣原体抗体检测.有支气管镜检查指征的患儿行支气管镜下肺泡灌洗及肺泡灌洗液定量培养.结果 201例MP肺炎混合其他病原感染103例（51.2％）,其中肺炎衣原体52例（25.9％）,病毒29例（14.4％）,细菌22例（10.9％）.病毒中以呼吸道合胞病毒感染最多见（17例,8.5％）.29例MP混合病毒感染中,26例为3岁以下病例（89.7％）,而52例MP混合肺炎衣原体感染者中40例为3岁以上（76.9％）.与非混合感染组相比,混合感染组热程更长（热程大于10 d者24.5％,40.8％）,更多发生胸腔积液（11.2％,23.3％）,影像学上更多出现大片状阴影（35.7％,51.5％）.MP混合细菌感染组外周血白细胞[（14.28 ±4.99）×109/L]、CRP[ 69（ 32.5 ～ 99.5）mg/L]及肺泡灌洗液中性粒细胞比例[0.86（0.63 ～0.91）]高于非混合感染组[ （9.06±3.47）×109/L,3（0～31.0） mg/L,0.44（0.03 ～0.88）].结论 半数以上MP肺炎存在混合感染；以肺炎衣原体最常见,其次为病毒,细菌混合感染率低；年幼儿童以病毒混合感染为主,年长儿以肺炎衣原体混合感染为主；伴血白细胞/CRP升高者,应重点注意合并细菌感染.

Objective To investigate the incidence and clinical features of mixed infections in children with Mycoplasma pneumoniae （MP） pneumonia.Method A total of 201 cases diagnosed as MP pneumonia were investigated for mixed infections by sputum bacterial culture,respiratory virus antigen detection and serum Chlamydia pneumoniae antibody test.For those with the indications for bronchoscopy,we also did bronchoalveolar lavage and lavage bacterial culture. Result A high incidence （ 103/201,51.2% ） of mixed infections in children with MP pneumonia was revealed. The most frequent co-infected pathogen was Chlamydia pneumoniae （52,25.9%）,followed by viruses （ 29,14.4% ）,and bacteria（ 22,10.9% ）. Among viruses,respiratory syncytial virus was the most common （17,8.5%）,followed by adenovirus（ 6,3.0% ）,parainfluenza virus type Ⅲ （4,2.0% ） and influenza virus type B （ 2,1.0% ）.Sputum bacterial culture was positive in 14/201 （7.0%） cases,Streptococcus pneumonia being most common（6,3.0% ）.BALF culture yielded positive results in 11.6% （8/69）,Streptococcus pneumonia was also common（5,7.3% ）.Among 29 cases with MP and virus coinfection,26 were younger than 3 years （89.7% ）,while for MP and Chlamydia pneumoniae coinfection,most of them were older than 3 years （40/52,76.9% ）. Compared with non-mixed infections,those with mixed infections had longer fever duration （24.5% and 40.8% longer than 10 d）,more frequently developed pleural effusion （ 11.2%,23.3% ） and large area of shadow in chest imaging （35.7%,51.5% ）.White blood cell[ （ 14.28 ±4.99） × 109/L],Creactive protein （CRP） [69（32.5-99.5） mg/L] and neutrophil ratio in BALF[0.86（0.63-0.91 ） ] were much higher in children with mixed bacterial infections than that in non-mixed infections [ （9.06 ± 3.47） ×109/L,3 （0-31.0） mg/L,0.44 （0.03-0.88 ） ].But no significant difference was found in peripheral blood neutrophil proportion between mixed bacterial infections （0.38 ± 0.25 ） and non-mixed infections（0.51 ±0.19）.Conclusion More than half of cases with MP pneumonia had mixed infections,most commonly caused by Chlamydia pneumonia followed by viruses.The incidence of mixed infections with bacteria was low.Mixed infections with virus were more common in young children,while mixed infection with Chlamydia pneumoniae was more common in older ones.Bacterial infections should be paid more attention,especially those caused by Streptococcus pneumoniae,for those with high peripheral white blood cell counts,high CRP levels and high proportion of neutrophils in BALF.