Objective The aim of this study is to investigate the macrolide resistance rate and molecular type with multiple-locus variable-number tandem-repeat analysis(MLVA)of Mycoplasma pneumoniae of Beijing in 2016 in pediatr...Objective The aim of this study is to investigate the macrolide resistance rate and molecular type with multiple-locus variable-number tandem-repeat analysis(MLVA)of Mycoplasma pneumoniae of Beijing in 2016 in pediatric patients.Methods Real-time quantitative polymerase chain reaction(PCR)was used to identify M.pneumoniae,and MLVA was performed.The domain V of the 23 S rRNA was sequenced to detect macrolide-resistant point mutations.We also investigated the activities of antibiotics against M.pneumoniae isolates in vitro.Results The PCR detection rate of M.pneumoniae in children in Beijing was 40%,and the macrolide resistance rate was 66%.The A2063 G mutation in the 23 S rRNA V region is the dominant mutation(137/146,93.84%),whereas the A2064 G mutation is rare(9/146,6.16%).Seventy-three samples were typed successfully by MLVA typing,including 86.3%(63/73)were MLVA type 4-5-7-2,and 13.7%(10/73)were MLVA type 3-5-6-2.No other types were found.No strains were resistant to levofloxacin or tetracycline.Conclusion In 2016,a specific decrease in the macrolide resistance rate occurred in Beijing.The detection rate and macrolide resistance rate of outpatients are lower than those of inpatients.The A2063 G mutants M.pneumoniae have high levels of resistance to erythromycin and azithromycin.The primary MLVA type is 4-5-7-2,followed by 3-5-6-2.No other MLVA types were detected.No strains resistant to tetracycline or levofloxacin were found in vitro.展开更多
Objective To develop a multiple-locus variable-number tandem-repeat(VNTR)analysis(MLVA)assay for Acinetobacter pittii typing.Methods Polymorphic VNTRs were searched by Tandem Repeats Finder.The distribution and polymo...Objective To develop a multiple-locus variable-number tandem-repeat(VNTR)analysis(MLVA)assay for Acinetobacter pittii typing.Methods Polymorphic VNTRs were searched by Tandem Repeats Finder.The distribution and polymorphism of each VNTR locus were analyzed in all the A.pittii genomes deposited in the NCBI genome database by BLAST and were evaluated with a collection of 20 well-characterized clinical A.pittii strains and one reference strain.The MLVA assay was compared with pulsed-field gel electrophoresis(PFGE)for discriminating A.pittii isolates.Results Ten VNTR loci were identified upon bioinformatic screening of A.pittii genomes,but only five of them showed full amplifiability and good polymorphism.Therefore,an MLVA assay composed of five VNTR loci was developed.The typeability,reproducibility,stability,discriminatory power,and epidemiological concordance were excellent.Compared with PFGE,the new optimized MLVA typing scheme provided the same and even greater discrimination.Conclusion Compared with PFGE,MLVA typing is a faster and more standardized alternative for studying the genetic relatedness of A.pittii isolates in disease surveillance and outbreak investigation.展开更多
基金supported by the National Natural Science Foundation of China[Grant No.81271890]Beijing Municipal Science&Technology Commission Grant[No.Z161100000116088 and Z1711000017081]
文摘Objective The aim of this study is to investigate the macrolide resistance rate and molecular type with multiple-locus variable-number tandem-repeat analysis(MLVA)of Mycoplasma pneumoniae of Beijing in 2016 in pediatric patients.Methods Real-time quantitative polymerase chain reaction(PCR)was used to identify M.pneumoniae,and MLVA was performed.The domain V of the 23 S rRNA was sequenced to detect macrolide-resistant point mutations.We also investigated the activities of antibiotics against M.pneumoniae isolates in vitro.Results The PCR detection rate of M.pneumoniae in children in Beijing was 40%,and the macrolide resistance rate was 66%.The A2063 G mutation in the 23 S rRNA V region is the dominant mutation(137/146,93.84%),whereas the A2064 G mutation is rare(9/146,6.16%).Seventy-three samples were typed successfully by MLVA typing,including 86.3%(63/73)were MLVA type 4-5-7-2,and 13.7%(10/73)were MLVA type 3-5-6-2.No other types were found.No strains were resistant to levofloxacin or tetracycline.Conclusion In 2016,a specific decrease in the macrolide resistance rate occurred in Beijing.The detection rate and macrolide resistance rate of outpatients are lower than those of inpatients.The A2063 G mutants M.pneumoniae have high levels of resistance to erythromycin and azithromycin.The primary MLVA type is 4-5-7-2,followed by 3-5-6-2.No other MLVA types were detected.No strains resistant to tetracycline or levofloxacin were found in vitro.
基金supported by the Major Infectious Diseases Such as AIDS and Viral Hepatitis Prevention and Control technology major projects(grants 2013ZX-100040101,2013ZX10004805-005)the key projects of state key laboratory of infectious disease prevention and control(grants 2014SKLID102)
文摘Objective To develop a multiple-locus variable-number tandem-repeat(VNTR)analysis(MLVA)assay for Acinetobacter pittii typing.Methods Polymorphic VNTRs were searched by Tandem Repeats Finder.The distribution and polymorphism of each VNTR locus were analyzed in all the A.pittii genomes deposited in the NCBI genome database by BLAST and were evaluated with a collection of 20 well-characterized clinical A.pittii strains and one reference strain.The MLVA assay was compared with pulsed-field gel electrophoresis(PFGE)for discriminating A.pittii isolates.Results Ten VNTR loci were identified upon bioinformatic screening of A.pittii genomes,but only five of them showed full amplifiability and good polymorphism.Therefore,an MLVA assay composed of five VNTR loci was developed.The typeability,reproducibility,stability,discriminatory power,and epidemiological concordance were excellent.Compared with PFGE,the new optimized MLVA typing scheme provided the same and even greater discrimination.Conclusion Compared with PFGE,MLVA typing is a faster and more standardized alternative for studying the genetic relatedness of A.pittii isolates in disease surveillance and outbreak investigation.
