Jørgensen Hannah J, Mathisen Tone, Løvseth Astrid, Omoe Katsuhiko, Qvale Kristina S, Loncarevic Semir
Department for Feed and Food Hygiene, National Veterinary Institute, Oslo, Norway.
FEMS Microbiol Lett. 2005 Nov 15;252(2):267-72. doi: 10.1016/j.femsle.2005.09.005. Epub 2005 Sep 26.
Mashed potato made with raw bovine milk was suspected to have been the source of a food poisoning outbreak. Almost 8 x 10(8)Staphylococcus aureus CFU g(-1) were detected in the mashed potato. S. aureus was also found in bulk milk from the farm that had supplied milk for the mashed potato. Isolates from mashed potato and bulk milk were positive for the gene encoding staphylococcal enterotoxin H (seh), and the corresponding protein toxin, SEH, was detected by ELISA in the mashed potato. Production of SEH by S. aureus isolates from mashed potato (n = 4) and bulk milk (n = 4) was also demonstrated by ELISA. Sequencing of seh from one mashed potato isolate and one bulk milk isolate confirmed that the gene was a variant seh, and that the genes in both isolates were identical. Macrorestriction of chromosomal DNA with Sma1 followed by pulsed-field gel electrophoresis of seh-positive S. aureus from mashed potato and bulk milk revealed indistinguishable banding patterns between isolates from both sources. It seems likely that raw bovine milk used in the preparation of mashed potato contained S. aureus that subsequently produced sufficient SEH in the mashed potato to cause food poisoning.
用生牛乳制作的土豆泥被怀疑是一起食物中毒暴发的源头。在土豆泥中检测到近8×10⁸CFU/g的金黄色葡萄球菌。在为制作土豆泥供应牛奶的农场的散装牛奶中也发现了金黄色葡萄球菌。从土豆泥和散装牛奶中分离出的菌株对编码葡萄球菌肠毒素H（seh）的基因呈阳性，并且通过酶联免疫吸附测定法（ELISA）在土豆泥中检测到了相应的蛋白质毒素SEH。通过ELISA也证实了从土豆泥（n = 4）和散装牛奶（n = 4）中分离出的金黄色葡萄球菌能够产生SEH。对一株土豆泥分离株和一株散装牛奶分离株的seh进行测序，证实该基因是seh的一个变体，并且两株分离株中的基因是相同的。用Sma1对染色体DNA进行宏观限制性内切酶消化，随后对来自土豆泥和散装牛奶的seh阳性金黄色葡萄球菌进行脉冲场凝胶电泳，结果显示来自两种来源的分离株之间的条带模式无法区分。制作土豆泥所用的生牛乳似乎含有金黄色葡萄球菌，这些金黄色葡萄球菌随后在土豆泥中产生了足以导致食物中毒的SEH。
