Dept. of Pharmacy and Nutrition, Federal Univ. of Espírito Santo - Campus Alegre, Alegre, Brazil.
Dept. of Basic Sciences of Life, Federal Univ. of Juiz de Fora - Campus Governador Valadares, Governador Valadares, Brazil.
J Food Sci. 2018 Feb;83(2):377-385. doi: 10.1111/1750-3841.14019. Epub 2018 Jan 16.
Although most Brazilian dairy products meet high technological standards, there are quality issues regarding milk production, which may reduce the final product quality. Several microbial species may contaminate milk during manufacture and handling. If antimicrobial usage remains uncontrolled in dairy cattle, the horizontal transfer of antimicrobial resistance genes in foodstuffs may be of particular concern for both food producers and dairy industry. This study focused on the evaluation of putative Gram positive cocci in Minas cheese and of antimicrobial and biocide resistance genes among the isolated bacteria. Representative samples of 7 different industrially trademarked Minas cheeses (n = 35) were processed for selective culture and isolation of Gram positive cocci. All isolated bacteria were identified by DNA sequencing of the 16S rRNA gene. Antimicrobial resistance genes were screened by PCR. Overall, 208 strains were isolated and identified as follows: Enterococcus faecalis (47.6%), Macrococcus caseolyticus (18.3%), Enterococcus faecium (11.5%), Enterococcus caseliflavus (7.7%), Staphylococcus haemolyticus (7.2%), Staphylococcus aureus (4.3%), Staphylococcus epidermidis (2.9%), and Enterococcus hirae (0.5%). The genetic markers mecA (78.0%) and smr (71.4%) were the most prevalent, but others were also detected, such as blaZ (65.2%), msrA (60.9%), msrB (46.6%), linA (54.7%), and aacA-aphD (47.6%). The occurrence of opportunist pathogenic bacteria harboring antimicrobial resistance markers in the cheese samples are of special concern, since these bacteria are not considered harmful contaminating agents according to the Brazilian sanitary regulations. However, they are potentially pathogenic bacteria and the cheese may be considered a reservoir for antimicrobial resistance genes available for horizontal transfer through the food chain, manufacturing personnel and consumers.
虽然大多数巴西乳制品符合高科技标准，但在牛奶生产方面存在质量问题，这可能会降低最终产品的质量。在制造和处理过程中，几种微生物可能会污染牛奶。如果在奶牛养殖中仍然无法控制抗菌药物的使用，那么食品中抗菌药物耐药基因的水平转移可能会引起食品生产者和乳制品行业的特别关注。本研究专注于评估米纳斯干酪中的假定革兰氏阳性球菌，以及分离细菌中的抗菌药物和杀生物剂耐药基因。从 7 种不同的工业化商标米纳斯奶酪中抽取代表性样本（n=35）进行选择性培养和革兰氏阳性球菌分离。所有分离的细菌均通过 16S rRNA 基因的 DNA 测序进行鉴定。通过 PCR 筛选抗菌药物耐药基因。总体而言，共分离并鉴定了 208 株细菌，分别为：屎肠球菌（47.6%）、巨球菌（18.3%）、粪肠球菌（11.5%）、黄色肠球菌（7.7%）、溶血葡萄球菌（7.2%）、金黄色葡萄球菌（4.3%）、表皮葡萄球菌（2.9%）和海氏肠球菌（0.5%）。mecA（78.0%）和 smr（71.4%）是最常见的遗传标记，但也检测到了其他标记，如 blaZ（65.2%）、msrA（60.9%）、msrB（46.6%）、linA（54.7%）和 aacA-aphD（47.6%）。在奶酪样品中存在携带抗菌药物耐药标记的机会性病原体细菌令人特别关注，因为根据巴西卫生法规，这些细菌不被认为是有害的污染菌。然而，它们是潜在的致病菌，而奶酪可能被视为可通过食物链、制造人员和消费者进行水平转移的抗菌药物耐药基因的储存库。
