利用电子鼻区分羊奶中不同浓度抗生素

采用电子鼻方法,利用主成分分析(PCA)和线性判别分析(LDA)进行数据采集,对添加硫酸土霉素、盐酸链霉素、硫酸庆大霉素的羊奶进行快速检测与识别.结果表明,PCA只能区分盐酸链霉素样品,LDA的区分效果明显优于PCA.电子鼻能够有效的区分添加以上3种不同浓度抗生素的羊奶.     

High throughput detection of antibiotic residues in milk by time-resolved fluorescence immunochromatography based on QR code

ABSTRACT

Herein, we have successfully established a novel, rapid, and simple lateral-flow immunoassay based on time-resolved fluorescence and biotin-streptavidin to detect the residues of various antibiotics in milk. The fluorescence signal and sensitivity of immunochromatography were enhanced through biotinylated antibody coupled with streptavidin europium microspheres. Moreover, due to the use of a QR Code and fluorescent reader, quantitative detection and real-time data uploading can be achieved. Under the optimal conditions, the various antibiotic residues were detected in the milk samples. The results showed that the limits of detection of tylosin, lincomycin and doxycycline were 0.10, 0.06, and 0.27 ng/mL, respectively. The recoveries of the spiked milk samples were 88.9%~127%, with coefficients of variation less than 11%, and the test strip can be stored at room temperature for 12 months. This study shows that the proposed time-resolved fluorescence immunoassay is sensitive, rapid and reliable, and has the potential to be used for detection of veterinary antibiotic residues in food safety fields.     

Phenotypic and Genotypic Antimicrobial Resistance Traits of Foodborne Staphylococcus aureus Isolates from Shanghai

Staphylococcus aureus is a recognized pathogen in humans, which causes nosocomial infections and food poisoning. The transmission of antibiotic resistant S. aureus (ARSA), especially methicillin‐resistant S. aureus, between food products and humans has become a serious problem. Hence, it is necessary to monitor S. aureus through the food supply chain. In this study, the disk diffusion method and epsilometer test were performed to determine the prevalence of ARSA in 78 foodborne isolates using 18 antibiotics. The highest resistance frequency was found for penicillin G (74.4%), followed by erythromycin (59.0%) and clindamycin (44.9%), whereas no vancomycin‐resistant isolates were found. The 78 isolates could be subtyped into 31 resistance profiles and 11 clusters based on their antimicrobial susceptibility. Furthermore, Polymerase chain reaction (PCR) screening for the presence of 13 genes conferring antibiotic resistance was conducted. The presence of resistance genes was relatively high: bla_TEM (80.8%), ermB (41.0%), grlA (38.5%), ermC (35.9%), and aac6’/aph2” (35.9%). The incidence of antibiotic resistance was significantly correlated to food types (p = 0.018), with isolates from meat and raw milk more resistant to antibiotics than those from frozen food and vegetables.     

益生乳杆菌质粒抗生素抗性基因与其耐药性的相关性探讨

采用K-B药敏纸片法检测了5株具有潜在益生乳杆菌的耐药性,通过质粒消除,分析了菌株质粒与耐药性之间的联系,应用PCR确定了质粒决定的耐药基因.5株乳杆菌对万古霉素、多粘菌素B以及链霉素等7种抗生素普遍表现出抗性,但主要对四环素敏感.采用SDS与SDS-高温两种方法消除戊糖乳杆菌CH8的质粒后,菌株CH8表现出头孢噻吩和氯霉素敏感性.设计β-内酰胺类抗性基因blr、ECP-1569和nps-1以及氯霉素抗性基因cmlA、cat和cmlA1的引物进行PCR,与目的产物测序比对表明,戊糖乳杆菌CH8的质粒上含有β-内酰胺类抗性基因blr,该基因与其头孢噻吩抗性有关.该研究为探讨乳酸菌的抗药基因转移性提供了前期基础,有助于益生乳杆菌安全性评价体系的建立与完善.     

红曲与核霉素

因红曲中含有桔霉素,将使我国的红曲出口受到很大影响。本文介绍了红曲中桔霉素的产生及合成途径;桔霉素的分子式、结构、物理和化学性质、毒性、抑菌性和检测方法等内容。     

天然纤维床垫的抗菌防螨性能

为研究天然纤维床垫的抗菌防螨性能,对棕纤维床垫、纯黄麻床垫及黄麻艾叶混合床垫进行扫描电镜、红外光谱、压缩性、透气透湿性、抗菌防螨等性能测试,并对测试结果进行了比较。从床垫结构和化学物质作用两方面分析了抗菌性和防螨性的机理。结果表明,在几种床垫中棕纤维床垫具有最优的透气透湿性能,纯黄麻床垫对大肠杆菌的抑菌率达到80％,驱螨率达到98％,均达到国标标准的要求,具有优异的抗菌防螨性能。     

拉曼光谱技术在农产品药物残留检测中的应用

近年来,农产品药物残留超标引发了一系列食品安全问题,为了保障国家食品安全、保护消费者健康,需要对农产品中的药物残留进行定性定量检测。表面增强拉曼散射技术 (Surface-enhanced Raman scattering , SERS) 是一种极具吸引力的工具,可用于高效检测农药残留。本文介绍了表面增强拉曼光谱检测技术的概况,简介了拉曼增强基底,分析了表面增强拉曼光谱技术在药物标准溶液、农产品(肉类、水产品、果蔬和其他部分农产品等)药物残留检测领域中的研究现状,并针对当前农产品药物残留检测的发展趋势进行前景展望。     

Characterization of Antibiotic Resistance Genes from Lactobacillus Isolated from Traditional Dairy Products

Lactobacilli are widely used as starter cultures or probiotics in yoghurt, cheese, beer, wine, pickles, preserved food, and silage. They are generally recognized as safe (GRAS). However, recent studies have shown that some lactic acid bacteria (LAB) strains carry antibiotic resistance genes and are resistant to antibiotics. Some of them may even transfer their intrinsic antibiotic resistance genes to other LAB or pathogens via horizontal gene transfer, thus threatening human health. A total of 33 Lactobacillus strains was isolated from fermented milk collected from different areas of China. We analyzed (1) their levels of antibiotic resistance using a standardized dilution method, (2) their antibiotic resistance gene profiles by polymerase chain reaction (PCR) using gene‐specific primers, and (3) the transferability of some of the detected resistance markers by a filter mating assay. All Lactobacillus strains were found to be resistant to vancomycin, but susceptible to gentamicin, linezolid, neomycin, erythromycin, and clindamycin. Their susceptibilities to tetracycline, kanamycin, ciprofloxacin, streptomycin, quinupristin/dalfopristin, trimethoprim, ampicillin, rifampicin, and chloramphenicol was different. Results from our PCR analysis revealed 19 vancomycin, 10 ciprofloxacin, and 1 tetracycline‐resistant bacteria that carried the van(X), van(E), gyr(A), and tet(M) genes, respectively. Finally, no transferal of the monitored antibiotic resistance genes was observed in the filter mating assay. Taken together, our study generated the antibiotic resistance profiles of some milk‐originated lactobacilli isolates and preliminarily assessed their risk of transferring antibiotic gene to other bacteria. The study may provide important data concerning the safe use of LAB.     

污水处理厂中四环素类抗生素残留及其抗性基因污染 特征研究进展

四环素类抗生素以其突出的抗菌性能和较低的副作用而被广泛用于细菌感染疾病的治疗和控制, 污水处理系统作为环境中四环素类抗生素及其抗性基因的一个重要污染点源, 已引起广泛关注。尽管如此, 目前关于四环素类抗生素在污水处理过程中的降解行为及影响因子, 及其对降解微生物抗药性的选择性效应方面的研究还较少。在分析总结国内外四环素类抗生素污染现状基础上, 对污水处理过程中四环素类抗生素的去除行为及影响因素等进行分析, 探讨了其抗性基因在污水处理过程中的污染特征, 同时分析了四环素类抗生素对其抗性基因的诱导、演变和传播的影响, 并对今后的研究发展方向进行了展望, 以期为从污水处理系统达到控制和去除四环素类抗生素及其抗性基因提供方向和依据。     

制药废水的处理方法

综述了目前国内外常用的制药废水的处理方法,并介绍了两种新型的处理方法,即微波处理法和超声波处理法,最后对制药废水处理方法的研究进行了展望。