Antibiotic resistance and microbial composition along the manufacturing process of Mozzarella di Bufala Campana
Antibiotic resistance and microbial composition along the manufacturing process of Mozzarella di Bufala Campana
复制标题
DOI：
10.1016/j.ijfoodmicro.2008.09.021
复制
发表时间：
2008-12-10
影响因子：
5.4
通讯作者：
Perozzi, Giuditta
中科院分区：
文献类型：
--
作者：
Devirgihis, Chiara;Caravelli, Antonella;Perozzi, Giuditta
2006年1月，所有欧盟成员国都禁止在牲畜中使用抗生素作为生长促进剂，这导致环境细菌中出现抗生素耐药菌株，包括在人类和动物G1呼吸道中定植的革兰氏阳性非致病菌。在意大利和其他地中海国家，发酵食品使用原底物中存在的环境细菌。而不是定义基因型的工业起始物，代表了具有官方PDO指定（受保护原产地名称）的奶酪和肉类产品的很大比例。本研究对意大利PDO产品水牛Mozzarella奶酪中分离的乳酸菌和其他乳酸菌进行了微生物学和分子分析，目的是确定对四环素、红霉素和卡那霉素耐药的基因。我们从零售产品中分离出500多个LAB菌落，以及生产中使用的生牛奶和天然乳清发酵剂。微生物学分析表明，这些分离株中约有50%为乳酸菌，通过种类和菌株组成以及表型和基因型抗生素耐药性的测定进一步对其进行了表征。为了克服仅选择可培养物种的培养依赖方法的局限性，我们还从奶酪中存在的整个微生物组中提取了总DNA，并使用分子方法研究了特定抗生素抗性基因的存在。抗生素耐药性的遗传决定因素几乎全部在从未经加工的原料中分离出来的细菌中确定，而最终上市的产品不含表型耐药乳酸菌，即显示MIC值高于微生物断点。总的来说，我们的研究结果表明，制造这种典型奶酪所需的传统程序，如高温处理，导致最终产品细菌计数低，生物多样性低，缺乏抗生素抗性乳酸菌的显著存在。(c) 2008 Elsevier B.V.版权所有
The use of antibiotics as growth promoters in livestock, banned in all EU member states in January 2006, has led to selection of antibiotic resistant strains within environmental bacteria, including gram-positive, non pathogenic bacteria that colonize the G1 tract of humans and animals. In Italy and in other Mediterranean countries, fermented foods employing environmental bacteria pre-existing in the raw substrates. rather than industrial starters of defined genotype, represent a significant proportion of cheese and meat products carrying the official PDO designation (Protected Designation of Origin). Our study focused on the microbiological and molecular analysis of lactobacilli and of other lactic acid bacteria (LABs) isolated from the Italian PDO product water buffalo Mozzarella cheese, with the aim of identifying genes responsible for tetracycline, erythromycin and kanamycin resistance. We isolated over 500 LAB colonies from retail products, as well as from raw milk and natural whey starters employed in their production. Microbiological analysis showed that about 50% of these isolates were represented by lactobacilli, which were further characterized in terms of species and strain composition, as well as by determining phenotypic and genotypic antibiotic resistance. To overcome the limits of culture-dependent approaches that select only cultivable species, we have also extracted total DNA from the whole microbiome present in the cheese and investigated the presence of specific antibiotic resistance genes with molecular approaches. Genetic determinants of antibiotic resistance were identified almost exclusively in bacteria isolated from the raw, unprocessed substrates, while the final, marketed products did not contain phenotypically resistant lactobacilli, i.e. displaying MIC values above the microbiological breakpoint. Overall, our results suggest that the traditional procedures necessary for manufacturing of this typical cheese, such as high temperature treatments, lead to a final product with low bacterial counts, lower biodiversity and lack of significant presence of antibiotic resistant lactobacilli. (c) 2008 Elsevier B.V. All rights reserved.