Department of Food Science and Technology, Faculty of Agriculture and Natural Resources, University of Khazar, Azadi Av., Daryaye 9 St., P.O. Box: 46315-389, Mahmudabad, Iran.
Int J Food Microbiol. 2013 May 15;163(2-3):159-65. doi: 10.1016/j.ijfoodmicro.2013.02.020. Epub 2013 Mar 6.
Staphylococcal food poisoning results from the consumption of food in which enterotoxigenic staphylococci have grown and produced toxins. The present study was conducted with three principal aims: i) to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of Zataria multiflora Boiss. essential oil (EO) against Staphylococcus aureus ATCC 29213, ii) to evaluate the effect of subinhibitory concentrations (subMIC) of EO on the growth of bacteria over 72 h (at 25 and 35 °C), and iii) to investigate the expression of genes involved in the production of staphylococcal enterotoxins SEA, SEC and SEE over 72 h at 35 °C. The MIC and MBC of Z. multiflora Boiss. EO were 0.03 and 0.04%, respectively. Colony counting at 24, 48 and 72 h of 3 day cultures grown in the presence of 75%MIC of the EO showed that the growth rate was reduced 2.16, 2.78 and 2.91 log 10 cfu/ml at 25 °C, and 1.34, 2.35 and 2.57 log 10 cfu/ml at 35 °C, respectively, compared to control cultures. SubMIC levels of EO also significantly decreased the expression of staphylococcal enterotoxin (SE)-related genes and therefore the production of SEs in a dose dependent manner. For example, when cultured with 75% MIC, the transcriptional levels of sea, sec, see and agrA were decreased 11.7, 9.3, 10.45 and 10.3 fold after 18 h and 13.9, 11.21, 12.44 and 12.52 fold after 72 h in comparison to control, respectively.
金黄色葡萄球菌食物中毒是由于摄入了生长并产生毒素的产肠毒素性金黄色葡萄球菌的食物引起的。本研究有三个主要目的：i）确定荜茇精油（EO）对金黄色葡萄球菌 ATCC 29213 的最小抑菌浓度（MIC）和最小杀菌浓度（MBC），ii）评估亚抑菌浓度（subMIC）EO 对细菌生长的影响，在 72 小时内（在 25 和 35°C 下），iii）在 35°C 下 72 小时内研究与金黄色葡萄球菌肠毒素 SEA、SEC 和 SEE 产生相关基因的表达。荜茇精油（Z. multiflora Boiss. EO）的 MIC 和 MBC 分别为 0.03%和 0.04%。在存在 EO 的 75%MIC 的情况下培养 3 天的 24、48 和 72 小时的菌落计数显示，与对照培养物相比，在 25°C 下的生长速度分别降低了 2.16、2.78 和 2.91 log 10 cfu/ml，在 35°C 下分别降低了 1.34、2.35 和 2.57 log 10 cfu/ml。EO 的亚 MIC 水平也显著降低了金黄色葡萄球菌肠毒素（SE）相关基因的表达，从而以剂量依赖的方式降低了 SE 的产生。例如，在用 75%MIC 培养时，与对照相比，sea、sec、see 和 agrA 的转录水平分别在 18 小时后降低了 11.7、9.3、10.45 和 10.3 倍，在 72 小时后降低了 13.9、11.21、12.44 和 12.52 倍。
