摘要目的 探讨耐药肺炎支原体(MP)肺炎患儿的临床特点及流行基因型特征.方法 选取2013年1月至2015年10月首都儿科研究所附属儿童医院临床诊断为MP肺炎,且咽拭子或肺泡灌洗液MP聚合酶链反应(PCR)检测阳性的96例标本,其中男55例,女41例;1～3岁19例(19.8％),＞3 ～5岁18例(18.7％),＞5 ～13岁2个月59例(61.5％).对所有标本进行23S rRNA耐药基因检测,根据耐药基因检测结果分为耐药组和敏感组.同时,对所有标本进行P1-基因限制性片段长度多态性分析(P1-RFLP)及多位点可变数目串联重复序列分析(MLVA)基因分型,比较耐药组与敏感组及不同基因型MP感染的临床特点,包括患儿年龄、性别、住院时间、症状、体征、发热时间、使用大环内酯类抗生素后体温恢复正常时间、血常规白细胞总数、C反应蛋白(CRP)及胸部X线和/或肺部CT检查等影像学表现.采用SPSS 11.5统计学软件进行处理,P＜0.05为差异有统计学意义.结果 96例标本中,81例在23S rRNA中检测到耐药基因,耐药率高达84％.根据耐药基因的检测结果分为耐药组(81例)和敏感组(15例).耐药组患儿的发热时间、住院时间、并发症发生率、CRP水平均高于敏感组,差异均有统计学意义(t =2.061、Z=-3.368,x2=5.856、Z=-2.165,均P＜0.05);年龄、白细胞总数、发生叶或段实变比例、应用大环内酯类抗生素后体温恢复正常时间差异均无统计学意义(均P＞0.05).对96例标本进行P1-RFLP基因分型,5例P1分型未成功,91例中P1-Ⅰ型81例(89.0％),P1-Ⅱc型10例(11.0％).P1-I型较P1-Ⅱc型组患儿住院时间及应用大环内酯类抗生素后体温恢复正常时间长,差异均有统计学意义(Z=-2.197、2.237,均P＜0.05);年龄、发热时间、白细胞总数、CRP水平、影像学发生叶或段实变比例、并发症发生率比较差异均无统计学意义(均P ＞0.05);P1-Ⅰ型中73例(90％)为耐药菌株,8例(10％)为敏感菌株;P1-Ⅱc型中3例(30％)为耐药菌株,7例(70％)为敏感菌株.P1-Ⅰ型MP中耐药菌株明显多于P1-Ⅱc型,二者比较差异有统计学意义(x2=19.209,P＜0.01).对96例标本进行改良MLVA基因分型,其中M4-5-7-2型82例(85.5％),M3-5-6-2型11例(11.5％),M4-5-5-2型1例(1.0％),M4-5-6-2型2例(2.0％),由于M4-5-5-2型和M4-5-6-2型例数较少,仅比较M4-5-7-2型和M3-5-6-2型MP感染患儿的表现.M4-5-7-2型组患儿较M3-5-6-2型组住院时间及应用大环内酯类抗生素后体温恢复正常时间长,差异均有统计学意义(Z=-2.406、-4.472,均P＜0.05);年龄、发热时间、白细胞数、CRP水平、影像学发生叶或段实变比例、并发症发生率比较差异均无统计学意义(均P＞0.05);M4-5-7-2型中74例(90％)为耐药菌株,8例(10％)为敏感菌株;M3-5-6-2型中4例(36％)为耐药菌株,7例(64％)为敏感株.M4-5-7-2型MP中耐药菌株明显多于M3-5-6-2型,二者比较差异有统计学意义(x2=17.022,P＜0.01).结论 耐药MP菌株感染者与敏感MP菌株感染者相比,发热时间及住院时间长、并发症发生率及CRP水平高.我国MP菌株耐药率高,基因型以P1-Ⅰ型、M4-5-7-2型为主,基因型可能与耐药有关.

abstractsObjective To explore the clinical features of children infected with macrolide-resistant (MR) Mycoplasma pneumonia(MP) isolates and genetic typing of all isolates.Methods Polymerase chain reaction(PCR) of MP positive in 96 nasopharyngeal or bronchoalveolar lavage fluid (BALF) samples were collected from patients diagnosed as MP pneumonia in the Affiliated Children's Hospital of the Capital Institute of Pediatrics from January 2013 to October 2015.Fifty-five cases were male,41 cases were female;19 cases (19.8％) were 1 to 3 years old,18 cases (18.7％) were more than 3 to 5 years old,59 cases(61.5％) were more than 5 to 13 years and 2 months old.These samples were tested for MR associated mutations in the 23S rRNA of MP,and were divided into the MR group and the macrolide-sensitive (MS) group.Furthermore,the genotype of all the isolates were performed by conducting P1-restriction fragment length polymorphism(P1-RFLP) analysis and multiple-locus variable-number tandem-repeat analysis (MLVA) method.The clinical characteristics including the age,gender,hospitalization duration,symptoms,signs,fever duration,fever duration after macrolide therapy,white blood cell count,C-reactive protein (CRP),chest X-ray and/or chest computed tomography,which were compared between different groups.SPSS 11.5 software was used to analyze the statistical data.Statistical significance was determined at the 0.05 level of a two-tailed test.Results MR mutations were identified in the 23S rRNA gene in 81 specimens (84％),and the 96 specimens were divided into MR group(81 cases) and MS group (15 cases).There were statistical differences in fever duration,hospitalization duration,the incidence of complications and CRP level between the MR group and MS group (t =2.061,Z =-3.368,x2 =5.856,Z =-2.165,all P ＜ 0.05).There were no statistical differences in age,white blood cell count,consolidation percentage on chest radiography and fever duration after macrolide therapy(all P ＞ 0.05).All the 96 isolates were performed by adopting P1-RFLP typing,but 5 isolates were not typed successfully,while 81 cases (89.0％) isolates were typed as P1-Ⅰ and 10 isolates(11％) were typed as P1-Ⅱ c.The hospitalization duration and the fever duration after macrolide therapy in the P1-Ⅰ were longer than the P1-Ⅱ c group,and the difference was statistically significant (Z =-2.197,2.237,all P ＜ 0.05).There were no statistical differences in age,fever duration,white blood cell count,CRP level,consolidation percentage on chest radiography and the incidence of complications (all P ＞ 0.05).Seventy-three cases (90％) of P1-Ⅰ group were MR isolates,8 cases (10％) were MS isolates;3 cases (30％) of the P1-]Ⅱ c group were MR isolates,7 cases (70％) were MS isolates.The MR isolates in P1-Ⅰ group were much more than P1-Ⅱ c group.There was obvious statistical difference in the proportion of MR isolates between 2 groups (x2 =19.209,P ＜ 0.01).All the 96 isolates were performed by modified MLVA typing,82 cases(85.5％) were typed as M4-5-7-2,11 cases(11.5％) were typed as M3-5-6-2,1 case (1.0％) was typed as M4-5-5-2,and 2 cases (2.0％) were typed as M4-5-6-2.Because there were less cases of the M4-5-5-2 and M4-5-6-2 type,only the clinical data of M4-5-7-2 and M3-5-6-2 group were compared.The hospitalization duration and the fever duration after macrolide therapy in the M4-5-7-2 group were longer than the M3-5-6-2 group,and the difference was statistically significant(Z =-2.406,-4.472,all P ＜ 0.05).There were no statistical differences in age,fever duration,white blood cell count,CRP level,consolidation percentage on chest radiography and the incidence of complications(all P ＞ 0.05).Seventy-four cases (90％) of the M4-5-7-2 group were MR isolates,8 cases (10％) were MS isolates;4 cases (36％) of the M3-5-6-2 group were MR isolates,7 cases (64％) were MS isolates.The MR isolates in M4-5-7-2 group were much more than M3-5-6-2 group.There was obviously statistical difference in the proportion of MR isolates between 2 groups (x2 =17.022,P ＜ 0.01).Conclusions In the MR group,the children had longer fever duration and hospitalization duration,higher incidence of complications and higher CRP level than those in the MS group.The MR rates of MP in China was high.P1-Ⅰ and M4-5-7-2 are the predominate genotypes.There may be a correlation between genotype and MR.