健康老年人肠道中肠杆菌科细菌的分布及其耐药机制研究

Analysis on the distribution and antibiotic resistance mechanism of healthy elderly intestinal Enterobacteriaceae bacteria

目的分析健康老年人肠道菌群,探讨本地区健康老年人肠道中肠杆菌科细菌的分布及其耐药情况。方法取粪便标本分别接种于血平板、SS平板、麦康凯平板进行细菌培养,用全自动微生物鉴定仪和质谱仪鉴定细菌到种,采用K-B纸片扩散法进行药敏试验测定其耐药表型,PCR扩增测序再与GenBank上比对其耐药基因。结果在175例研究对象中,有59.4%(104/175)的健康老年人肠道中只有一种肠杆菌科细菌;细菌种类以大肠埃希菌为主,占88.0%。大肠埃希菌对IPM、CTX、AMC、FOX和CIP的耐药率分别为0%、27.9%、4.5%、1.3%和37.0%;肺炎克雷伯菌对IPM、CTX、AMC、FOX和CIP的耐药率分别为1.9%、5.8%、1.9%、1.9%和3.8%;两者相比较,大肠埃希菌对CTX、CIP的耐药率明显高于肺炎克雷伯菌(P<0.05)。ESBLs总携带率为17.4%,其中大肠埃希菌的携带率(24.0%)明显高于肺炎克雷伯菌(5.8%)(P<0.05);产ESBLs菌株的基因型,均为CTX-M型酶,其中以CTX-M-14最多,占57.8%。结论本研究获得了老年人肠道肠杆菌科细菌的分布特点及其耐药机制。健康老年人肠道中肠杆菌科细菌部分抗生素的耐药率比浙江省内医院肠杆菌科细菌统计结果低,这主要是和其ESBLs携带率较低相关;但同时也已有泛耐药细菌的出现,应提高警惕。

Objective To analyse the intestinal flora of healthy elderly, investigate the distribution and antibiotic resistance mech-anism of healthy elderly intestinal Enterobacteriaceae bacteria. Methods The stool specimens were cultured on blood plate,SS plate,MAC plate. The bacterial strain was identified by VITEK-2 compact and mass spectrometry. The resistance phenotypes of bacteria was determinated by K-B disk diffusion method. The resistance genes were amplificated by PCR and compared in GenBank. Results Amongthe 175 patients, a strain of Enterobacteriaceae was the most in healthy elderly intestinal, occupy 59.4% （104/175）. The most bacteriawere E. coli, accounted 88% . The resistance rates of E. coli to IPM,CTX, AMC, FOX and CIP were 0% , 27. 9% , 4. 5% , 1.3% and37%,respectively. The resistance rates of K. pneumonia were 1. 9%,5. 8%,1. 9%,1. 9% and 3. 8%,respectively. The resistancerates of E. coli to CTX, CIP were significantly higher than K. pneumonia （P 〈0. 05） . The total ESBLs carrying rate was 17. 4%,and theESBLs carrying rate of E. coli （24% ） was significantly higher than that K. pneumoniae （5. 8% ）,P 〈0. 05. All of the strains with ES-BLs carried the CTX-M type, and the CTX-M-14 was the most, occupy 57. 8% . Conclusion This research has obtained the distributioncharacteristics and antibiotic resistance mechanism of the elderly intestinal Enterobacteriaceae. The antibiotic resistance rates of Enterobacteriaceae are lower than the all Hospital of Zhejiang Province. This is mainly related with the low carrying rate of ESBLs. The bacteriaof pan drug resistant has appeared, so we should be vigilant.