| Staphylococcus aureus is an important pathogen that enterotoxin (SEs)generated by its secretion is an important factor in inducing food poisoning. Thereare many food poisoning caused by Staphylococcus aureus around the world. Andpneumonia and wound infections caused by SA accounted for10%in hospitalinfections; the antibiotics extensive use lead methicillin-resistant aureus (MRSA)appeared in large numbers. It has become one of the world’s three infection germsand others are HIV and hepatitis B tied.In this experiments combined with the results of previous studies, we studiedthe transcriptional level in the SA enterotoxin gene impact in different cultures and atdifferent stages of the medium of expression, as well as regulatory factors in theregulation.The strains we used are all from the laboratory, analyzes distribution andregularity of sec, sed and mecA gene in SAs in different sources.The total detection rates of sec, sed, and mecA in436Staphylococcus aureuspreservation of (from hair tools, human purulent tissue, knives, air, fruits andvegetables, soy products, meat, frozen food, raw milk and raw meat etc.) were24.1%,8.3%and8.7%, the sec’s rate was significantly higher than the other twotoxin genes.Sec is distributed in a variety of sources, the largest proportion of frozen food.Sed neither detected in the air, knives, hair tools, aquatic products and fruits andvegetables; the highest detection rate is raw meat. MecA except hair tools, knivesand soy products, the rest are distributed sources, including fruits and vegetablesand aquatic products in high detection rate.In this study we select the strains SA30, SA75, SA83which three strainsanalyzed the situation of each toxin genes are transcribed in a different medium. Theresults showed that: the expression of hlb is the maximum when strain SA83grewinto log phase; has little expression of the SEU; hlg not detected. Strain SA75hlband SEU in the largest expression is in the logarithmic phase; hlg were expressedmore and more, with the growth of time. The hlb in strain SA30expression of themaximum after entering the stable; hlg when entering the expression of themaximum stable; SEU are expressed in the whole process, expressed maximumamount at the10h.Staphylococcus aureus on the ability to use and catabolism different sugars aredifferent, less ability to lactose utilization and soluble starch, higher ability toglucose and sucrose. Sucrose most conducive to the expression of the SEA; solublestarch enhancement of expression of SEI is obvious; glucose played the weakenedrole when hld in the late logarithmic expression; hla only expressed with glucoseand sucrose, both are at6h, when access to a number of expression; hlb in TSB medium containing lactose just transcripted a very small amount, up to theexpression amount that enter the logarithmic phase at8h; expression of sucrose onhlg may have inhibited.RNA Ⅲ as a regulatory factor, although in each period has detected, but itsrole in the regulation of toxin production has not been clearly reflected.Many researches have shown that the growth environmental conditions ofStaphylococcus aureus has important implications for to form different types ofenterotoxins. Given the current situation, the specific culture conditions ofStaphylococcus aureus toxin produced becomes extremely important in further study.These academic achievements will be state to make quick judgments and providesjudged according to monitoring and tracking outbreaks and pollution disease whenenvironmental and food contamination cased by Staphylococcus aureus and thisprevalence. |
PDF Full Text Request