山东商品鸡养殖、屠宰、销售环节中细菌耐药性传播规律研究

发布时间：2018-04-25 10:13

本文选题：细菌耐药性 + 肉鸡产业链　；参考：《中国疾病预防控制中心》2016年硕士论文

【摘要】：为阐述肉鸡产业链细菌耐药性现状及耐药性传播规律,本研究采集肉鸡产业链养殖、屠宰和销售三个环节的108份样品,在六种抗生素平板上筛选耐药菌,通过对耐药菌的药物敏感性、分子分型及耐药基因的分析,了解耐药菌在肉鸡产业链中的分布,阐述其耐药特征,探讨耐药性在肉鸡产业链中的传播规律,为耐药性防控提供基础数据。108份样本共分离373株大肠杆菌,110株肺炎克雷伯菌和79株奇异变形杆菌(共562株耐药菌),大肠杆菌和肺炎克雷伯菌在三个环节中均有分离到,奇异变形杆菌仅在养殖环节中分离到。最小抑菌浓度(MIC)值的测定结果表明大肠杆菌,肺炎克雷伯菌,奇异变形杆菌均表现为对多种药物耐药,多重耐药菌(至少对三类抗生素耐药)的比例分别是88.2%,90.9%和84.8%,此外MIC值高,三种菌株中均有50%以上的菌株对三代头孢菌素的MIC值高于耐药折点的16倍以上。PCR筛查blacrx-M基因表明,三种菌均广泛携带blacTX-M,总携带率为65.7%,大肠杆菌、肺炎克雷伯菌和奇异变形杆菌的携带率分别为54.7%,63.6%和72.1%。大肠杆菌以blacrx-M-55为主,依次为blacrx-M-65, blacTx-M-14和blacr X-M-27肺炎克雷伯菌以blacrx-M-55和blacrx.M.15为主,依次为b lacTX-M-2 7, b lacTX-M-14, b lacTX-M.6 5和blac'rx-M.3~奇异变形杆菌以blacTx.u.65为主,依次为blacrx-M-55, blacrx.Mq4和blacrx.M-90~ blacrx-M-6S. blacrx-M-S5和blacTX-M-14在三种菌种中均有检出。从肉鸡产业链的不同环节来看,养殖环节样本中分离菌株检出的基因亚型最多,包括blacTX-M-27, blacTX.M-65. blacrx.M-SS, blacrx-M-14, blacrx-M.lS和blacrx-M-90 o屠宰环节中检出亚型较少,仅检测到blacTX-M-27和blacrx.M-S5 o销售环节检出的基因型包括blacrx-M-s5, blacrx.Mq4和blacTX-M-27 ,而且blacrx-M.3基因仅在销售环节中出现。此外,在国内首次发现了携带blacTX-M-90的奇异变形杆菌。MLST分析显示,110株肺炎克雷伯菌共有32个ST型,ST1(22株)和ST37(16株)为主要优势型,分别占20%(22/110)和14.5%(16/110)。另有16个ST型共涉及49株菌(44.5%)为首次发现的ST型。不同环节来源菌株ST型不尽相同,有28株属于3个ST型的菌株同时来自两个环节,尚未检出相同ST型的肺炎克雷伯菌同时出现在三个环节。PFGE分析显示,奇异变形杆菌共分为34个亚型,携带4种bldCTX-Utype基因。25种不同亚型的53株奇异变形杆菌均携带blacrx-M-65基因。此外,ST37型肺炎克雷伯菌和027型奇异变形杆菌在种鸡场饲养员和商品鸡肛拭子样本中都有检出。上述研究结果显示山东肉鸡产业链来源的大肠杆菌、肺炎克雷伯菌、奇异变形杆菌均呈现多重耐药及高水平耐药的特征。大肠杆菌和肺炎克雷伯菌在三个环节中均有检出,变形杆菌只在养殖环节中检出；养殖环节耐药菌最高,菌种分布也最为多样,提示养殖环节是本食品链中耐药菌的主要来源；不同环节来源菌株基因型不尽相同,提示不同环节间存在耐药克隆株的传播,但并不是耐药性传播的主要机制；不同环节来源菌株超广谱B-内酰胺酶基因blacrx-M广泛携带,相同亚型的blacrx-M基因在来自三个环节的不同种属的菌株中均有检出,养殖环节blacrx M耐药基因亚型最丰富,提示耐药菌从养殖环节向屠宰和销售环节传播；在商品鸡及养殖者的样本中检测出相同菌株亚型及blacix-u基因型的菌株,提示养殖环节中存在耐药菌在动物和人之间的传播。本研究通过对肉鸡产业链三个环节及三个种属的菌株研究,初步获得了该产业链中耐药菌的分布状况及传播特点,该研究结果将为阐述耐药菌的传播规律,阻断耐药菌在肉鸡产业链中的传播提供重要的参考数据。
[Abstract]:In order to describe the drug resistance and drug resistance of broiler chicken industry chain , 108 samples from three links of breeding , slaughter and sale of broiler chicken were collected . The results showed that the drug resistance , molecular typing and drug resistance genes were 84.2 % , 93.9 % and 84.8 % , respectively . The results showed that there were 32 ST - type , 1 - ST1 ( 22 / 110 ) strains and 14 . 5 % ( 16 / 110 ) strains . The results showed that there were 32 ST - type strains , 1 ST1 ( 22 / 110 ) and 14 . 5 % ( 16 / 110 ) strains .
The most resistant strains of drug - resistant bacteria in the culture are the most diverse , and it is suggested that the breeding link is the main source of drug - resistant bacteria in the food chain .
The genotype of isolates from different links was different , suggesting that there was a spread of drug - resistant clones between different links , but not the main mechanism of drug resistance transmission .
The blacrx - M gene of the same subtype is most abundant in the strains of different species from three links , and the blacrx - M gene subtype of the same subtype is the most abundant , suggesting that the drug - resistant bacteria can be transmitted from the breeding link to the slaughtering and selling links ;
The strains of the same strain and blacix - u genotype were detected in the samples of commercial chickens and mariculture , suggesting that there was a spread of drug - resistant bacteria between animals and humans . This study preliminarily obtained the distribution and transmission characteristics of drug - resistant bacteria in the industry chain . The results of this study will provide important reference data for the introduction of drug - resistant bacteria and blocking the spread of drug - resistant bacteria in broiler industry chain .

【学位授予单位】：中国疾病预防控制中心
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：R155

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