| 谈潘莉,汪浙炯,孙爱华,严杰,赵金方.大肠埃希菌临床菌株优势β-内酰胺酶基因型及其诱导表达与抑制的研究[J].中华流行病学杂志,2015,36(5):484-490 |
| 大肠埃希菌临床菌株优势β-内酰胺酶基因型及其诱导表达与抑制的研究 |
| Predominant β-lactamase genotypes of Escherichia coli isolates and induction and inhibition mechanisms of β-lactamase gene expression |
| 收稿日期:2014-11-29 出版日期:2015-05-12 |
| DOI：10.3760/cma.j.issn.0254-6450.2015.05.016 |
| 中文关键词: 大肠埃希菌 β-内酰胺类抗生素 耐药性 β-内酰胺酶/基因型/表达 组氨酸激酶/抑制剂 |
| 英文关键词: Escherichia coli β-lactam antibiotics Resistance β-lactamase/genotype/expression Histidine kinase/inhibitor |
| 基金项目:国家自然科学基金(81271893); 浙江省自然科学基金(LY12H19002); 浙江省卫生厅科研项目(2011KYA005) |
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| 中文摘要: |
| 目的 了解浙江地区大肠埃希菌临床菌株优势β-内酰胺酶基因型及其携带模式、β-内酰胺类抗生素诱导β-内酰胺酶基因表达及组氨酸激酶抑制剂氯氰碘柳胺(CLO)抑制其表达的作用。方法 采用微量稀释法和E-test检测大肠埃希菌临床菌株对β-内酰胺类抗生素耐药率和最低抑菌浓度(MIC)。采用PCR及其产物测序法检测大肠埃希菌耐药菌株β-内酰胺酶基因型及携带模式。采用实时荧光定量RT-PCR和β-内酰胺酶确证试验分别检测1/4 MIC头孢噻肟或青霉素及CLO对大肠埃希菌耐药菌株β-内酰胺酶基因转录和表达的影响。结果 浙江地区61.7%(285/462)大肠埃希菌对青霉素、氨苄青霉素、头孢西丁、头孢噻肟和头孢他啶耐药。285株耐药菌株中, TEM和CTX-M基因检出率(83.2%和75.1%)显著高于KPC、SHV和OXA基因(1.4%～10.2%)(P<0.01), 两种以上β-内酰胺酶基因携带率(68.8%)显著高于单基因(31.2%)(P<0.01), 其中61.4%菌株携带TEM+CTX-M基因(P<0.01)。除KPC基因外, 1/4 MIC头孢噻肟和青霉素能诱导89株β-内酰胺酶单基因菌株TEM、CTX-M、SHV和OXA mRNA水平迅速升高(P<0.01), 但可被50～500 μg/ml CLO所抑制(P<0.01)。100 μg/ml CLO预处理后, 82.8%～85.6%耐药菌株对上述抗生素敏感(P<0.01), β-内酰胺酶检出率也从95.1%下降至16.1%(P<0.01)。结论 TEM和CTX-M是浙江地区大肠埃希菌临床菌株优势β-内酰胺酶基因型, 并以TEM-1+CTX-M为优势携带模式。低浓度头孢噻肟和青霉素可经细菌二元信号系统上调β-内酰胺酶基因表达, 但可被组氨酸激酶抑制剂CLO所抑制。 |
| 英文摘要: |
| Objective To understand the predominant β-lactamase genotypes and their carrying modes of Escherichia coli isolates in Zhejiang province, and the effects of β-lactam antibiotics on inducing or histidine kinase inhibitor closantel (CLO) on inhibiting the expression of β-lactamase genes. Methods Micro-dilution method and E-test were applied to measure the resistant rate and minimal inhibitory concentration (MIC) in E. coli isolates against β-lactam antibiotics. PCR and sequence analysis of PCR products were conducted to detect the β-lactamase genotypes and their carrying modes. Real-time fluorescent quantitative RT-PCR and β-lactamase confirmation test were performed to determine the influence of 1/4 MIC penicillin and cefotaxime, and CLO on the transcription and expression of β-lactamase genes in the resistant E. coli isolates. Results Among the 462 E. coli strains isolated in Zhejiang, 285(61.7%) were resistant to penicillin, ampicillin, cefoxitin, cefotaxim and ceftazidime. In the 285 resistant isolates, the detection rate of TEM or CTX-M β-lactamase gene (83.2% or 75.1%) was significantly higher than that of KPC, SHV or OXA β-lactamase gene (1.4%-10.2%) (P<0.01) and the carrying rate of two or more β-lactamase genes (68.8%) was also significantly higher than that of single β-lactamase gene (31.2%) (P<0.01), and 61.4% of the resistant isolates carried TEM+CTX-M genes (P<0.01). Except KPC gene, 1/4 MIC of cefotaxim and penicillin induced a rapid increase of TEM-mRNA, CTX-M-mRNA, SHV-mRNA or OXA-mRNA levels (P<0.01), but 50-500 μg/ml CLO inhibited these levels (P<0.01). After pre-treatment with 100 μg/ml CLO, 82.8%-85.6% of the resistant isolates became sensitive to β-lactam antibiotics (P<0.01), while the detection rate of β-lactamases was also decreased from 95.1% to 16.1% (P<0.01). Conclusion TEM and CTX-M are the predominant β-lactamase genotypes in E. coli isolates in Zhejiang and TEM+CTX-M is the predominant carrying mode of β-lactamase genes. Low concentrations of β-lactam antibiotics can up-regulate the expression levels of β-lactamase genes in E. coli through bacterial two-component signaling systems, but this effect can be inhibited by CLO, a histidine kinase inhibitor. |
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