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目的研究母婴感染的单增李斯特菌分子生物学特性,并对其进行同源性分析,为流行病学调查提供参考。方法取母婴的血液等临床标本,做常规细菌培养及染色检查,使用VITEK2Compact全自动微生物分析仪进行鉴定,采用K-B纸片扩散法做药敏试验。提取分离菌的基因组DNA,采用通用引物PCR扩增16SrRNA片段,回收后测序,与GenBank中收录菌株的16SrRNA基因序列进行BLAST序列同源性比对。从200条随机引物中筛选10条随机引物(P1-P10),采用随机扩增多态性DNA(RAPD)技术对分离菌DNA进行电泳图谱的同源性分析。结果分离菌经常规鉴定为威氏李斯特菌。药敏试验显示分离菌氨苄西林/舒巴坦、头孢哌酮/舒巴坦、青霉素、红霉素、万古霉素、复方新诺明、利福平、左氧氟沙星、庆大霉素、环丙沙星均敏感,对头孢曲松与头孢他啶均耐药。PCR扩增分离菌16SrRNA全序列为1 471bp,经BLAST序列比对,与F2365菌株的同源性达99.4%,确定为单增李斯特菌。RAPD指纹图谱表明10条随机引物中有5条引物扩增的电泳图谱带型一致。结论 16SrRNA序列分析技术及RAPD指纹图谱分析表明母婴感染的单增李斯特菌株间同源,对母婴感染的预防与诊治有重要意义。
OBJECTIVE: To study the molecular biology of Listeria monocytogenes infected by maternal-to-infant infection and to analyze its homology to provide reference for epidemiological investigation. Methods Blood samples were taken from mother and infant for routine bacterial culture and staining. The samples were identified by VITEK2 Compact automatic microbiological analyzer and K-B disk diffusion method was used for drug sensitivity test. The genomic DNA of the isolated bacteria was extracted. The 16SrRNA fragment was amplified by universal primers and sequenced. The 16S rRNA gene sequences of the 16S rRNA gene sequences of GenBank were compared for BLAST sequence homology. Ten random primers (P1-P10) were screened from 200 random primers. The homology of the isolates was analyzed by random amplified polymorphic DNA (RAPD). Results The isolates were routinely identified as Listeria monocytogenes. Susceptibility tests showed that the isolates ampicillin / sulbactam, cefoperazone / sulbactam, penicillin, erythromycin, vancomycin, cotrimoxazole, rifampin, levofloxacin, gentamycin, Star sensitive, ceftriaxone and ceftazidime are resistant. The full-length 16S rRNA sequence of PCR amplification was 1 471 bp. The sequence of BLAST was 99.4% homologous to F2365, which was identified as Listeria monocytogenes. The RAPD fingerprinting indicated that the bands of 5 bands in 10 random primers were identical. Conclusion 16S rRNA sequence analysis and RAPD fingerprinting indicate that homologous strains of Listeria monocytogenes infected by maternal and infant are important for the prevention and diagnosis of maternal-to-infant infection.