產腸毒素金黃色葡萄球菌之完全檢測與影響其增殖與產毒之因子

THE COMPLETE DETECTION OF ENTEROTOXIGENIC STAPHYLOCOCCUS AUREUS AND FACTORS AFFECTING GROWTH AND PRODUCTION OF ENTEROTOXINS

利用Baird Parker egg yolk-tellurite-pyruvate 培養基與Mannitol salt-4% egg Yolk 培養基交互選擇性培養後挑取金黃色葡萄球菌（Staphylococcus aureus）之典型菌落，鏡檢後進行凝固酶試驗與熱安定型核酸分解酶試驗，俟均為陽性時再進一步利用逆受身紅血球凝集試驗方法（Reversed passive hemagglutination test） 測定分離菌株之腸毒素型別與葡萄球菌凝固酶型別法（Coagulase typing of Staphyloccooccus） 測定凝固酶型別。依據上述之方法檢測市售食品167件，金黃色葡萄球菌之污染率為41.3%，其中73.9%具產腸毒素之能力，而產生之腸毒素中以A型為最多，佔毒素型菌株之51.0%，次為C型佔15.7%，又凝固酶型別則以四型為最多佔分離茵株之40.6%次為III型佔26.1%。另自食品中毒樣品中分離之50株菌種中具產腸毒素能力者佔74%，產生之腸毒中以A型為最多佔產腸毒素型菌株之43.2%而凝固酶型別則以VII型者最多佔64%次為III型佔28%。污染之產腸毒素金黃色葡萄球菌於食品中若置於35±2℃中培養時其生菌數之增加與腸毒素之反應情形與培養時間成正相關，但6±2℃培養時兩者均受到抑制。溫度升高至60±2℃時或可致死金黃色葡萄球菌，但卻無法破壞已污染於食品中之腸毒素。

The complete detection for enterotoxigenic Staphylococcus aureus was carried out by culture with selective incubation of Baird Park egg yolk-tellurite-pyruvate medium (BP) and Mannitol salt-4% egg yolk medium (MS-EY). After microscopic identification of suspicious colonies, a coagulase test and a thermostable nuclease test were followed. These positive isolates were further detected for enterotoxins by Reversed passive hemagglutination (RPHA) and fur coagulase type by Coagulase typing of Staphylococcus. The contamination of S. aureus in 167 marketing samples was observed by the complete detection method. The result showed that 41.3% of the samples was contaminated by S. aureus and 73.9% of isolates was found with the capability of enterotoxin production. It was found that the highest enterotoxin A producing isolate was 51% and the next was 15.7% for enterotoxin C. While the order of the coagulase type of all isolates was type VII in 40. 6% and type III in 26.1% respectively. On the other hand, the rate of enterotoxin producing strain in 50 isolates from the suspicious food which was sampled from food borne disease was 74%. In this case, enterotoxin A producing isoalte was 43. 2% of enterotoxin producing strain. For coagulase type, the highest was type VII in 64% and the next was type III in 28%. When the contaminated food were incubated at 35±2°C, the total aerobic count of S. aureus and the positive reaction in enterotoxins test were positively correlated, but at 6±2°C, both case were totally inhibited . When the temperature of incubation raised to 60 ±2°C, the vegetative cells of S. aureus were killed, but the enterotoxin which had already contaminated was not destroyed or detoxified.