Dept. of Bacteriological Diagnosis Laboratory, Samsun Veterinary Control Inst., Atakum, Turkey.
Dept. of Food Hygiene and Technology, Faculty of Veterinary Medicine, Univ. of Ondokuz Mayis, Samsun, Turkey.
J Food Sci. 2018 Jun;83(6):1716-1722. doi: 10.1111/1750-3841.14172. Epub 2018 May 26.
The aim of this study was to analyze the presence of genes encoding staphylococcal enterotoxins and methicillin resistance in Staphylococcus aureus isolates obtained from water buffalo milk and dairy products. A total of 200 samples (100 raw milk, 50 clotted cream, and 50 cheese samples) was collected from different dairy farms and smallholders in Samsun, Turkey. All samples were analyzed using the standard procedure EN ISO 6888-1 and isolates were confirmed for the presence of the target 16S rRNA specific for Staphylococcus genus specific and nuc gene specific for S. aureus species by PCR. S. aureus was identified in 30 of 100 milk (30%), 9 of 50 clotted cream (18%), and 17 of 50 cheese (34%) samples. A total of 99 isolates was confirmed as S. aureus. Genotypic methicillin resistance was evaluated using PCR for the mecA gene. Out of 99 isolates, nine (9%) were found to be methicillin resistant (mecA gene positive). Twelve out of 99 (12%) S. aureus isolates were found positive for one or more genes encoding the enterotoxins. The gene coding for enterotoxin, sea, was the most frequent (five isolates, 41.6%), followed by sec (two isolates, 16.6%), sed (1 isolates, 8.3%) and see (1 isolate, 8.3%). While three isolates (25%) contained both sec and sed, none of the samples was positive for seb. In conclusion, the presence of se gene-positive and methicillin-resistant S. aureus in buffalo milk and products revealed that consumption of these products is a potential risk of foodborne infection in this region.
Enterotoxigenic and methicillin-resistant S. aureus (MRSA) in milk and dairy products is an important public health problem. Especially in traditional dairy products, Staphylococcal enterotoxins may cause food poisoning due to consumption of raw or unpasteurized milk products.
本研究旨在分析从水牛奶和乳制品中分离的金黄色葡萄球菌（S. aureus）分离株中存在的肠毒素基因和耐甲氧西林基因。
从土耳其萨姆松不同奶牛场和小农户收集了 200 个样本（100 份生奶、50 份凝乳奶油和 50 份奶酪）。所有样本均采用标准程序 EN ISO 6888-1 进行分析，并通过 PCR 确认存在针对葡萄球菌属的目标 16S rRNA 特异性和针对金黄色葡萄球菌种的 nuc 基因特异性。
在 100 份牛奶样本中有 30 份（30%）、50 份凝乳奶油中有 9 份（18%）和 50 份奶酪中有 17 份（34%）样本中检出金黄色葡萄球菌。共确认 99 株金黄色葡萄球菌。使用 mecA 基因的 PCR 评估基因型耐甲氧西林。在 99 株分离株中，有 9 株（9%）被鉴定为耐甲氧西林（mecA 基因阳性）。在 99 株金黄色葡萄球菌分离株中，有 12 株（12%）被发现携带一种或多种编码肠毒素的基因呈阳性。编码肠毒素 sea 的基因最为常见（5 株，41.6%），其次是 sec（2 株，16.6%）、sed（1 株，8.3%）和 see（1 株，8.3%）。虽然有 3 株（25%）分离株同时携带 sec 和 sed，但没有一株样本检测到 seb。
在水牛奶和奶制品中发现 se 基因阳性和耐甲氧西林金黄色葡萄球菌表明，在该地区，食用这些产品存在食源性感染的潜在风险。
牛奶和乳制品中的肠毒素性和耐甲氧西林金黄色葡萄球菌（MRSA）是一个重要的公共卫生问题。特别是在传统乳制品中，由于食用生奶或未经巴氏消毒的奶制品，金黄色葡萄球菌肠毒素可能导致食物中毒。
