| Background and objective:Mycoplasma pneumoniais one of the main pathogens causing respiratory infections in both children and adult.Worldwide epidemics of M.pneumoniae infection occur every 3-7 years especially in spring and summer.The subtypes of M.pneumoniae were variouslyin different epidemic periods.Currently P1 gene restriction fragment length polymorphism(P1-RFLP)and multilocus variable-number tandemrepeat(VNTR)analysis(MLVA)method have been the most common molecular typing methods for M.pneumoniae.There is also significant variation in M.pneumoniae subtype distribution between time period,region and population in the worldwide.The macrolide-resistant problem of M.pneumoniae is increasingly serious because of the abuse of antibiotics.The previous studies have shown that the mutation ofM.pneumoniae resistant gene may be associated with genotype.With the development of molecular techniques,the methods of M.pneumoniaewere gradually mature.It is necessary to carry out comprehensive investigations of M.pneumoniae genotype and drug resistance mutation to reveal the distribution characteristics of M.pneumoniae subtypes andpredict trend of M.pneumoniae prevalence.A meta-analysis was conducted to understand the distribution characteristics of M.pneumoniae genotypes in the worldwide.Under this precondition,amolecular epidemiological survey was conducted to understand the distribution of M.pneumoniae genotypes and drug resistance mutation of impatiens in target hospital.What' more,the possible relationship between the results of RFLP and MLVA methods and the linkage between genotypes and drug resistance mutations was necessarily to discuss,which is aimed to provide a scientific basis on the local hospital M.pneumoniae monitoring,prevention,and clinical treatment.Methods:1.Meta-analysis:We conducted a systematic literature review for studies of M.pneumoniae subtypes in English and Chinese through several databases.Eligible articles were screened and selected based on the inclusion and exclusion criteria by two authors independently.Random-effects model were applied to calculate the pooled prevalence of different M.pneumoniae subtypes,and subgroup analyses examined prevalence estimates across time,locations,and populations.All meta-analyses were performed using R software(version 3.2.1)and SAS(version 9.3,SAS Institute Inc.,USA).2.Analysis of M.pneumoniae subtypes:Patients with Respiratory tract infection were enrolled from department of pediatrics and pneumology department whoseage were more than 50 years old in ZhongDa hospital.The throat swaps of patients and epidemiological investigation were conducted On the basis of informed consent.After 16SrRNA gene amplified by Nest-PCR to detect M.pneumoniae clinical strains,we used MLVA and Pl-RFLP analysis to compare characteristics of M.pneumoniae.3.Analysis ofmacrolide resistance-associated mutations:The 23SrRNA gene was amplified and sequenced of M.pneumoniae clinical strains.According to the result of sequencing analysis,macrolide resistance-associated mutations were detected and analyzed.4.Statistical analysis:Using excel to establish database and SPSS 19.0 or SAS 9.3 software to analyze the data.Qualitative data were described with rate or proportion and analyzed with Chisquare test or Fisher's exact test.Quantitative data were described with means and standard orthe median and interquartile and analyzed with Wilcoxon test or Kruskal-Wallis H test.Results:1.A total of 42 eligible studies were identified,including 40 studies related to the PI genotyping with 5027 cases,and 16 studies related to the MLVA with 1956 cases.The pooled prevalence of type l,type 2,and mutations were 73.80%(95%CI:67.86 79.34),26.21%(95%CI:20.67 32.16),13.25%(95%CI:7.61 20.15)respectively;The pooled prevalence of M4-5-7-2,M3-5-6-2,M3-6-6-2,and other types were 68.97%(95%CI:59.55 77.70),15.41%(95%Cl:10.41 21.20),5.49%(95%Cl:2.34 9.90),6.71%(95%Cl:4.72 9.02)respectively.The subtypeswere obvious different in different time,region and the population analyzed by Subgroup and Meta regression analysis.2.The prevalence of M.pneumoniae from patients with respiratory tract infectionin children was 27.6%in the target hospital.The number of successful gene classification by PCR-RFLP method was 90,the prevalence of type 1 and type 2 was 21.1%(19/90)and 78.9%(71/90).Type 2c was accounted for 50.7%(36/71).The number of successful gene classification by MLVA method was 102.The prevalence of type M3-6-6-2 was 40.2%(41/102)which was highest than other types.The prevalenceof type M3-5-6-2,M4-5-7-2,other subtypes were 37.3%(38/102),16.7%(17/102),and5.9%(6/102)respectively.100%of M4-5-7-2 specimens were P1 type 1,and 81.2%of M3-5-6-2,and M3-6-6-2 specimens were P1 type 2 or 2c.24 cases of elderly were successful typed by P1-RFLP.The prevalence of type 1,type 2 and 2c were 12.5%(3/24),87.5%(21/24),and 61.9%(13/21).30 caseswere successful parted by MLVA.The prevalence of type M3-5-6-2,M3-6-6-2 was both 43.3%(13/30),and type M4-5-7-2 and M3-6-7-2 were 10%(3/30)and 3.3%(1/30).100%of M4-5-7-2 specimens were P1 type 1,and 66.7%of M3-5-6-2,and M3-6-6-2 specimens were P1 type 2 or 2c.3,132 cases of children patients with M.pneumoniae specimens were found 21 resistant mutations,which resistant rate was 15.9%.Theresistant rates of A2063G and A2064G mutation were 90.5%(19/21)and 9.5%(2/21).The resistant rate of elderly patients with M.pneumoniae specimens was 10%(3/30).A2063G mutations accounted for 66.7%(2/3),T2611C mutation 33.3%(1/3).Successful classification of 101 cases,94.7%A2063G mutations were belongtype M4-5-7-2,5.3%(1/19)were belongtype M3-6-6-2.A2064G mutations was 1 case,belongs to the M3-5-6-2.T2611C mutations was 1 case,belongs to the M3-6-6-2.M.pneumoniae resistance may be related to type M4-5-7-2.4.M.pneumoniae infection may be associated with age and sex in children.Compared with the patients without M.pneumoniae infection,patients with M.pneumoniae infection were prone to occurfever,gastrointestinal andgeneralsymptoms,but not to appear the symptom of upper respiratory tract infection such as stuffy nose,runny nose,sneezing.Also N%and CRP were higher in M.pneumoniae patients.M.pneumoniae genotype distribution were statistical different indifferent age children M.pneumoniae infection.MLVA types M3-6-6-2 was mainly isolated among children age little than 3 and type M3-5-6-2 was mainly isolated among children age lager than 3.Conclusions:1.The prevalence of type 1 was higher than type 2 and there may be or will be a shift phenomenon between typ1 and type 2 in most regions currently.Type M4-5-7-2,M3-5-6-2 and M3-6-6-2 were the most common subtypes in MLVA types.Distribution of MLVA subtypes in different region and population has imparity.2.TheM.pneumoniae genotype in children and elderly patients were mainly M3--6-6-2 type 2 and M3-5-6-2 type 2.A possible correlation was observed between MLVAlocus 13 and P1 typing,but there still need more research for further discussion.3.The M.pneumoniae macrolide resistance rate in the regionwas lower than other places.A2063G mutation was in the dominant.Our study also provides more evidence that there is an association between MLVA type M4-5-7-2 and macrolide resistance. |
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