乳酸菌抗生素抗性的研究进展

对常见的乳酸菌的抗生素抗性及相关抗性基因进行了综述,并且简要概括了抗性基因在菌株之间的转移情况.     

四川泡豇豆原料表皮附生乳酸菌抗生素抗性及抗性基因污染分析

以鲜豇豆为研究对象,利用生理生化特征、16S r RNA、抗生素抗性和抗性基因检测分析其表皮附生乳酸菌对氯霉素(CHL)、四环素(TET)和氨苄青霉素(AMP)的抗性与抗性基因。结果表明:从鲜豇豆表皮共分离得到182株乳酸菌,分别属于Weissella confuse(50.0%)、Weissella cibaria(15.4%)、Enterococcus sulfurous(7.1%)和Lactococcus lactis subsp.lactis(27.5%)。32株(17.6%)乳酸菌对CHL和TET有抗性,其中,6株W.confuse(3.3%)和4株L.lactis subsp.Lactis(2.1%)对CHL单一抗性,4株W.confuse(2.1%)和5株L.lactis subsp.Lactis(2.7%)对TET单一抗性,6株W.confuse(3.2%)、2株W.cibaria(1.1%)、1株E.sulfurous(0.5%)和4株L.lactis subsp.Lactis(2.1%)对CHL和TET二重抗性;编码外排泵基因efr A、efr B、nor B、nor C、nor E和sug E中,efr B的检出率最高,达31.3%,efr B和sug E的检出率最低,为3.1%。TET被检抗性基因tet(A)、tet(B)、tet(C)、tet(D)、tet(H)和tet(L)中,tet(C)的检出率最高,达90.9%,tet(B)的检出率最低,为4.5%。      

基于SmartChip HT-qPCR分析不同食品中抗生素抗性基因的多样性及丰度

抗生素抗性基因（Antibiotics Resistance Genes,ARGs）广泛存在于各种环境中,被认为是一种新型环境污染物,对环境及人类健康具有潜在威胁。但是目前对于不同食品中多种ARGs赋存状况的研究仍然有限。该研究采用SmartChip高通量实时定量PCR方法（High-Throughput Quantitative Real-Time PCR,HT-qPCR）对水产品、发酵食品、肉类、蔬菜四大类样品中的ARGs及可移动遗传元件（Mobile Genetic Elements,MGEs）进行了定量分析。结果显示,被分析的15个样品中共检出9个ARGs大类,涉及234个ARGs亚类。所有样品中共有的ARGs亚类为79个,特有的为51个;水产品和肉类样品富集多种ARGs,这些基因表现出较高的丰度（最高可达3.6 copies/16S rRNA gene）。MGEs的检出数量达10个,其中所有样均检出整合子基因intI-1(clinic)和转座酶基因tnpA-01。ARGs抵抗机制分析结果表明,抗生素灭活机制、外排泵机制和细胞保护机制为主要的ARGs抵抗机制,抵抗机制贡献大小依次为：抗生素灭活机制>外排泵机制>细胞保护机制。该研究进一步丰富了对不同食品中ARGs赋存情况的认识,可为食品中ARGs的风险分析提供依据。     

不同来源的植物乳杆菌基因组和抗生素抗性

为了研究不同分离源对植物乳杆菌基因组和功能的影响,选取了来自发酵酱、泡菜、粪便3种环境的33株植物乳杆菌,通过比较基因组学手段研究菌株的基因组基本特征、直系同源基因、系统进化关系,并结合功能基因注释结果与表型结果分析菌株对抗生素的耐药性。系统发育树揭示了分离源对植物乳杆菌的遗传进化具有较为显著的影响;同源基因结果表明粪便源的菌株其特殊基因数量要高于泡菜源和发酵酱源菌株的数量。33株植物乳杆菌均含有环丙沙星、四环素、氯霉素、甲氧苄氨嘧啶和万古霉素的抗性基因,菌株对这些抗生素也表现出抗性;绝大多数菌株对庆大霉素、链霉素、卡那霉素、新霉素、氨苄西林敏感,在基因组中也没有相关抗性基因;而红霉素和克林霉素的基因和表型并不对应。抗生素实验结果说明,分离源对菌株影响较小,大部分基因型与表型可以对应,基因组学对研究植物乳杆菌的生理特性起一定的指导作用。     

重金属和抗生素抗性基因在土壤中的复合污染研究进展

抗生素滥用及其诱导产生的抗生素抗性基因(antibiotic resistance genes, ARGs)污染己经引起人们的广泛关注。与此同时,环境中重金属的污染状况也呈加剧趋势,与抗生素抗性基因不同,重金属在自然环境中很难被降解,二者同时存在不仅维持和加强了环境中的微生物对重金属的原有抗性,同时增强了对抗生素抗性基因的抗性。目前,重金属污染地区的养殖业中动植物细菌传染病的抗生素治疗总是无效的,其原因可能是重金属离子和抗生素抗性基因的协同抗性在选择压力下得到增强。本文总结了我国抗生素抗性基因和重金属元素在土壤中的污染状况及其复合污染特征,综述了这2类物质在土壤中的协同选择机制和综合修复措施,以期为重金属和抗生素抗性基因带来的污染所致危害的减轻和未来复合污染相关研究的深入提供参考。     

动物性水产品及其养殖环境中抗生素抗性基因的研究进展

抗生素抗性基因的污染问题已经在国际社会引起了广泛关注。中国作为抗生素使用大国,食品中抗性基因的污染更是关系到国计民生的重大问题,然而相关研究尚处在起步阶段,亟需更加系统、深入的研究。本文综述了动物性水产品及其养殖环境中抗生素抗性基因的赋存情况以及研究现状,总结了现阶段在水产养殖业中经常检测到的各种抗性基因,概述了其常用检测方法,以及近年来发展迅速的宏基因组学和机器学习分析方法在抗性基因研究中发挥的作用。最后,本文对近年来抗性基因相关健康风险评价的研究进展进行了归纳。本文将对如何进一步深入研究我国水产养殖中抗生素抗性基因的传播机制、预警和防控机制提供较为全面、系统的引导和借鉴。     

商品灭菌乳中常见抗生素抗性基因的筛查与定性分析

探究了市售常见商品灭菌乳中四环素类、氨基糖苷类、β-内酰胺类等抗生素抗性基因(Antibiotic resistance genes,ARGs)的分布与带染特征。以12种市售常见商品灭菌乳为研究对象,用CTAB法提取预处理后样品中的总DNA;超微量分光光度计测量DNA纯度与浓度;PCR扩增ARGs;PCR产物测序后提交GenBank进行序列比对,分析ARGs的种类;使用SPSS软件对ARGs检出率、样品品牌、包装类型、产品类型等进行相关性分析。结果显示,灭菌乳中可同时检出多种ARGs,检出率较高的基因分别为str B(93.75%)、aad B (92.71%)、sul1(85.42%)、bla_TEM82.29%)和tet C(58.33%),未在35种ARGs中检出bla_VEB、bla_PER、bla_DHA、bla_CMY2和bla_GIM。商品灭菌乳的品牌、包装、产地和保质期与aad A、aad B、str A、str B等抗性基因检出率显著相关。市售商品灭...     

水产品批发市场中抗生素抗性基因的污染分析

为了探究待售水产品中抗生素抗性基因(Antibiotic resistance genes,ARGs)在水产品批发市场中的扩散污染情况,选取上海市3个大型水产品批发市场作为研究对象,采用PCR的方法,对市场内部和市场附近的排污沟表层淤泥中5大类(4种磺胺类、8种四环素类、6种β-内酰胺类、5种氯霉素类、4种链霉素类)共27种ARGs进行了检测,并利用PCR-DGGE技术分析了细菌种群多样性。结果显示共有17种ARGs在批发市场淤泥中被检出,其中磺胺类、四环素类和链霉素类ARGs的检出率较高且检出种类较多,表明水产品批发市场含有种类丰富的ARGs,水产品以磺胺类、四环素类和链霉素类ARGs污染为主。对市场外围的检测显示市场外围区域ARGs的种类分布略低于市场内部,表明水产品批发市场中ARGs的存在会通过污水排放途径扩散到周边环境。DGGE图谱的分析结果显示,3个批发市场污泥样品细菌种类差异性较大,表明环境中ARGs的种类分布与细菌的种类并无直接关联。本研究表明水产品携带的ARGs会扩散到水产品批发市场中,导致水产品批发市场成为ARGs的重要储存库,以此造成的污染会进一步传播到周边环境,此外,这些种类丰富的ARGs重新扩散到待售水产品中的风险很大,需引起人们足够的重视。     

新型食品添加剂卡那霉素抗性基因编码蛋白的安全性评价

卡那霉素抗性基因是转基因植物中广泛使用的一类标志基因,近年来越来越多的转基因植物被批准商业化应用,由此衍生而来的含卡那霉素抗性基因及其编码产物的转基因食品也逐渐增多,因而其安全性受到普遍关注。FDA已批准卡那霉素抗性基因编码蛋白APH（3’）-Ⅱ可使为一类食品添加剂使用。本文对卡那霉素抗性基因的特性及其编码蛋白的安全性进行了综述评价。     

获得性抗生素抗性基因: 威胁发酵蔬菜食品安全的一种新型污染物

作为全球关注的新型面源污染之一,获得性抗生素抗性基因(AARGs)的水平转移成为食品安全领域近年来研究的新课题。发酵蔬菜是我国食品加工的重要组成部分,其发酵过程多样化的微生物参与为AARGs的传播和扩散转移提供了高风险的生态场所。为此,本文提出将AARGs作为威胁发酵蔬菜食品安全的一种新型污染物,对该类污染物的来源、潜在的传播途径以及国内外相关研究进行综述,并提出了当前形势下我国开展发酵蔬菜中AARGs污染研究的方向和防控建议。     

Prevalence, characterization, and antimicrobial resistance of Aeromonas strains from various retail food products in Mumbai, India

A total of 154 food samples (chicken, fish, and ready-to-eat sprouts) from various retail outlets in Mumbai, India, were analyzed for the presence of Aeromonas spp. over a period of 2 y (January 2006 to March 2008). Twenty-two Aeromonas isolates belonging to 7 different species were isolated from 18 (11.7%) food samples. The highest percentages of isolation were from chicken (28.6%) followed by fish (20%) and sprout (2.5%) samples. Aeromonas caviae, A. veronii bv. sobria, and A. salmonicida were the most frequently isolated species from sprouts, chicken, and fish samples, respectively. The genes encoding for putative virulence factors, cytotoxic enterotoxin (act), hemolysin (hly), aerolysin (aer), elastase (ahyB), and lipase (lip) were detected using polymerase chain reaction method in 59.1%, 40.9%, 22.7%, 54.5%, and 31.8% of the strains, respectively. The isolated Aeromonas strains were found to be positive for virulence factors, that is, amylase, DNase, gelatinase, protease, and lipase production. More than 60% isolates were also positive for β-hemolytic activity. All these food isolates were found to be resistant to ampicillin and bacitracin, and sensitive to gentamicin, 3rd-generation cephalosporins (ceftazidime, cephotaxime, ceftriaxone), and chloramphenicol. Seventeen (77.2%) isolates harbored single and/or multiple plasmids (approximately 5 to >16 kb). The XbaI digestion patterns of chromosomal DNA of these isolates, using pulsed field gel electrophoresis, showed high genetic diversity among these isolates. Our results demonstrate the presence of various Aeromonas spp. with virulence potential and antimicrobial resistance in different food products marketed in Mumbai, India. The potential health risks posed by consumption of these raw or undercooked food products should not be underestimated.     

五株嗜热链球菌抗药性研究

采用药敏纸片法研究了五株高产粘嗜热链球菌（KLDS3.1012、KLDS3.1014、KLDS-SM、KLDS3.0206、KLDS3.0207）对15种抗生素的敏感性,结果发现,KLDS3.1014对两种抗生素有抗性,KLDS3.1012、KLDS-SM、KLDS3.0206对3种抗生素有抗性,KLDS3.0207则表现出多重抗药性。对五株嗜热链球菌耐四环素基因（tet M,tet S,tet L）、耐红霉素基因（erm A,erm B,msr A/B）和耐氯霉素基因（cat）的初步研究表明,四环素耐受基因、红霉素耐受基因以及氯霉素耐受基因不位于基因组DNA上,同时,受试菌株均无质粒,因此可以初步判断受试菌株抗药性不会进行传递。      

Effects of different composting methods on antibiotic-resistant bacteria,antibiotic resistance genes,and microbial diversity in dairy cattle manures

Composting is a common practice used for treating animal manures before they are used as organic fertilizers for crop production. Whether composting can effectively reduce microbial pathogens and antibiotic resistance genes remain poorly understood. In this study, we compared 3 different dairy manure composting methods—anaerobic fermentation (AF), static compost (SC), and organic fertilizer production (OFP)—for their effects on antibiotic-resistant bacteria, antibiotic resistance genes, and microbial community diversity in the treated manures. The 3 composting methods produced variable and distinct effects on antibiotic-resistant bacteria, zoonotic bacteria, and resistance genes, some of which were decreased and others of which showed no significant changes during composting. Particularly, SC and OFP reduced chloramphenicol resistance gene fexA and opportunistic pathogen Vibrio fluvialis, whereas AF significantly reduced tetracycline resistance gene tetB and opportunistic pathogens Enterococcus faecium and Escherichia fergusonii. The compositions of microbial communities varied significantly during the composting processes, and there were significant differences between the 3 composting methods. In all 3 composts, the dominant phyla were Firmicutes, Proteobacteria, Bacteroidetes, and Actinobacteria. Interestingly, Firmicutes, Proteobacteria, and Bacteroidetes remained stable in the entire AF process, whereas they were dominated at the beginning, decreased at the early stage of composting, and rebounded at the later stage during SC and OFP. In general, SC and OFP produced a more profound effect than AF on microbial community diversities, pathogens, and dominant species. Additionally, Enterococcus aquimarinus was isolated from AF for the first time. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States function prediction analysis indicated that the genes related to membrane transport and amino acid metabolism were abundant in the 3 composts. The metabolism of amino acids, lipids, and carbohydrates increased as composting progressed. The biosynthesis of antibiotics was enhanced after fermentation in the 3 composting methods, and the increase in the SC was the most obvious. These results reveal dynamic changes in antibiotic-resistant bacteria, antibiotic resistance genes, microbial community composition, and function succession in different dairy manure composts and provide useful information for further optimization of composting practices.     

生物杀菌素在食品防腐中的应用研究进展

文章阐述了生物杀菌素的特点及在食品防腐中的应用研究概况,并对生物杀菌素的发展趋势进行了展望。     

Emerging issue of antibiotic resistance from food producing animals in India: Perspective and legal framework

Intensification of the animal husbandry sector in India has coincided with increased administration of antibiotics in food-producing animals for the treatment and prevention of diseases or to promote growth and enhance productivity. Antibiotics are an important tool for the livestock sector to meet the increased domestic demand of food for the burgeoning human population. The irrational use of antibiotics in food-producing animals has resulted in the occurrence of the residues in milk, meat, eggs, etc., and may lead to adverse health effects in consumers. Also there is growing concern that nonprudent use of antibiotics is linked with the escalating emergence of human infections with antibiotic-resistant pathogens of zoonotic importance. Regulations controlling the use of antibiotics in human and animal medicine in India are very weak and in its initial phases. The aim of this review is to investigate the Indian scenario with regards to the occurrence of antibiotics residues and emergence of antibiotic-resistant pathogens from foods of animal origin. Studies conducted in various parts of the country revealed varying concentrations of antibiotic residues and varying occurrence of antibiotic-resistant pathogens in animal-originated foods highlighting the need of effective control strategies for combating this potentially serious problem.     

Species distribution,antibiotic resistance and virulence traits in enterococci from meat in Tunisia

Antimicrobial resistance and the mechanisms implicated were studied in 119 enterococci from 105 meat samples from Tunisian markets. Almost 24.5% of recovered enterococci showed resistance against four or more antimicrobial agents and these isolates were identified to the species level. Enterococcus faecalis was the most prevalent species (41%). High percentages of erythromycin and tetracycline resistances were found among our isolates, and lower percentages were identified to aminoglycosides, ciprofloxacin and chloramphenicol. All tetracycline-resistant isolates carried the tet(M) and/or tet(L) genes. The erm(B) gene was detected in 78.5% of erythromycin-resistant isolates, ant(6)-Ia gene in 58.8% of streptomycin-resistant isolates, and cat(A) gene in one chloramphenicol-resistant isolate. Forty-eight isolates carried the gelE gene and exhibited gelatinase activity. The hyl and esp genes were detected in one and three Enterococcus faecium isolates, respectively. Streptomycin-resistant isolates showed a high genetic diversity by PFGE and MLST. Meat might play a role in the spread through the food chain of enterococci with these virulence and resistance characteristics to humans.     

多重PCR法检测与分析鱼塘生态系统大肠杆菌的耐药基因与整合子

了解在鱼塘生态系统中,大肠杆菌耐药基因、整合酶基因的携带情况,并对其进行分析,可以为控制细菌耐药基因传播提供科学的依据。本文对来自鱼塘生态系统的165株大肠杆菌进行了检测,发现大肠杆菌中普遍带有耐药基因,携带有耐药基因的比率为91．51％。携带有2种耐药基因以上菌株的比率为86．06％,大肠杆菌耐药基因的携带以多重耐药基因为主。进而对带有4种以上耐药基因的菌株检测,I整合子酶基因阳性检出率为87．84％,携带有7种耐药基因的菌株全部为I整合酶基因阳性;11型整合酶基因阳性菌株检出率10．81％;1株为阴性;检测中没发现有携带Ⅲ型整合酶基因菌株。可见I整合子介导的耐药机制占主导位置,并且通过整合子的整合作用向周围环境扩散。     

纳米食品研究进展

介绍了纳米食品的定义与功能，制造纳米食品的标准，从多方面阐述了纳米食品的应用，研究现状及发展前景。随着生活水平的提高和对健康的要求，纳米食品越来越受青睐。纳米食品将在21世纪起着对人类健康长寿的保障与调节作用，同时对生命科学的发展起着后天促进作用。