摘要
目的调查我院产ESBL肺炎克雷伯菌临床分离株16SrRNA甲基化酶基因的分布以及与耐药谱的关系，并初步探讨其在分子流行病学分析中的作用。方法收集我院临床2010年3月至9月分离出69株非重复产ESBL肺炎克雷伯菌，采用PCR法检测16SrRNA甲基化酶基因，并对阳性菌株进行ESBL基因及整合子基因分析，通过DNA直接测序确定。质粒接合试验和质粒消除试验确定16SrRNA甲基化酶基因的传播途径，利用ERIC-PCR技术进行基因分型。结果69株产ESBL肺炎克雷伯菌中有rmtB阳性菌株20株（28．9％），其中2株同时携带有rmtB和armA。在20株产16SrRNA甲基化酶菌株中，均携带有CTX—M基因，测序显示14株CTX—M-14基因，6株CTX—M-15基因；14株携带有TEM-1基因；8株携带有SHV基因，测序显示5株SHV-12基因，3株SHV-11基因；3株携带有OXA-10基因；3株携带有VBE-1基因。另有12株携带有intl阳性，含有5种不同的耐药基因盒，分别携带d（fA25、drfa1、drfA12、aadA1、aadA2、sat和blaVEB-1基因。ERIC—PCR法显示20株16SrRNA甲基化酶基因阳性的肺炎克雷伯菌主要分为5型，A型为优势流行克隆株。质粒接合和消除试验发现A型克隆株KP5和KPl6rmtB均位于一质粒上并通过接合传播。结论本院产ESBL肺炎克雷伯菌临床分离株中存在16SrRNA甲基化酶基因rmtB的普遍流行，导致对多种氨基糖苷类抗生素高水平耐药。rmtB可通过水平基因传播和克隆传播的两种方式进行播散，并且存在同时产ESBLs、16SrRNA甲基化酶和I类整合子的肺炎克雷伯菌的传播。
Objective To investigate the prevalence and distribution of 16S rRNA methylase gene and research the relationship with drug resistant spectrum. And preliminary explore its role in molecular epidemiology analysis. Methods Collected 69 clinical isolates of non repetitive ESBL-producing Klebsiella pneumoniae in our hospital from Mar to Sep 2010. Detection 16S rRNA methylation enzyme gene by PCR, and analyze ESBL genetype and integron gene of the positive strains. All PCR products were sequenced for determination. Plasmid conjugation test and plasmid elimination method to determine dissemination of 16S rRNA methylase gene. Then we used ERIC-PCR genotyping technology for the establishment of DNA finger- printing. Results In sixty-nine strains, twenty isolates were rmtB positive （28.9%）, two isolates were ar- mA positive, and two strains coproduce rmtB and armA. All positive isolates carried the CTX-M gene, det- emined by sequencing, 14 strains of CTX-M-14 gene, 6 strains of CTX-M-15 gene, 14 strains carried TEM- 1 gene, 8 strains carried SHV gene, sequencing showed that 5 strains of SHV-12 gene, 3 strains of SHV-11 gene, 3 strains carried OXA-10 gene, 3 strains carried VBE-1 gene. In addition, the intl gene was found in 12 isolates of 20 rmtB positive strains. All the intl gene positive strains were divided into five kinds gene cassettes, which contained drfA25, drfA1, drfA12, aadA1, aadA2, sat and blavEB-1 genes. Respectivily, 16S rRNA methylase gene positive strains were divided into five genetypes using ERIC-PCR technology. A genetype was the advantage popular clones. Conjugative plasmid and elimination test found that rmtB gene was located in a plasmid in KP5 and KP16 isolates with A genetype, and can disseminate by conjugation.Conclusion A high prevalence of 16S rRNA methylase gene--rmtB was found among clinical ESBL-producing K. pnettrnoniae isolates in our hospital, which could lead to resistant to almost all aminoglycoside at a high level. Both horizontal gene transfer and clonal spread were responsible fo
出处
《中华微生物学和免疫学杂志》
CAS
CSCD
北大核心
2012年第3期218-223,共6页
Chinese Journal of Microbiology and Immunology
