Murinda S E, Roberts R F, Wilson R A
Department of Food Science, Pennsylvania State University, University Park 16802, USA.
Appl Environ Microbiol. 1996 Sep;62(9):3196-202. doi: 10.1128/aem.62.9.3196-3202.1996.
Twenty-four Escherichia coli strains producing standard colicins were evaluated for inhibitory activity against 27 diarrheagenic E. coli strains of serotypes O15:H-, O26:(H11, H-), and O111:(H8, H11, H-), including O157:H7, representing diarrheagenic E. coli clones, 3, 4, 8, 9, and 10. Overlay techniques were used to assess inhibition on Luria agar and Luria agar supplemented with 0.25 micrograms of mitomycin C per ml to induce colicin production. As a group, the A colicins (Col) E1 to E8, K, and N inhibited 23 to 25 (85.2 to 92.6%) of the 27 diarrheagenic strains on mitomycin C-containing agar, whereas the most active group B colicins, Col D and Ia, inhibited 9 and 12 (33.3 and 44.4%), of the diarrheagenic strains, respectively. Col G and H and Mcc B17 inhibited 22 to 27 (81.5 to 100%) of the diarrheagenic strains on Luria agar but were suppressed on mitomycin C-containing agar medium. All O157:H7 strains evaluated were sensitive to Col E1 to E8, K, and N on mitomycin C-containing agar and to Col G and H and Mcc B17 on Luria agar. Sensitivity to colicins of the selected set of diarrheagenic strains was in the order diarrheagenic E. coli clone 9 > 4 > 3 > 10 > 8 and was not restricted to strains of a single clone or serotype. Strain 8C from clone 8 was resistant to most test colicins. There is potential for using colicins in foods and agriculture to inhibit sensitive diarrheagenic E. coli strains, including serotype O157:H7.
对24株产生标准大肠杆菌素的大肠杆菌菌株进行了评估，检测其对27株致泻性大肠杆菌菌株的抑制活性，这些致泻性大肠杆菌菌株的血清型为O15:H-、O26:(H11、H-)和O111:(H8、H11、H-)，包括代表致泻性大肠杆菌克隆3、4、8、9和10的O157:H7。采用覆盖技术在Luria琼脂和每毫升添加0.25微克丝裂霉素C以诱导大肠杆菌素产生的Luria琼脂上评估抑制作用。作为一组，A类大肠杆菌素（Col）E1至E8、K和N在含丝裂霉素C的琼脂上抑制了27株致泻性菌株中的23至25株（85.2%至92.6%），而活性最强的B类大肠杆菌素Col D和Ia分别抑制了9株和12株（33.3%和44.4%）致泻性菌株。Col G、H和Mcc B17在Luria琼脂上抑制了22至27株（81.5%至100%）致泻性菌株，但在含丝裂霉素C的琼脂培养基上受到抑制。所有评估的O157:H7菌株在含丝裂霉素C的琼脂上对Col E1至E8、K和N敏感，在Luria琼脂上对Col G、H和Mcc B17敏感。所选致泻性菌株对大肠杆菌素的敏感性顺序为致泻性大肠杆菌克隆9>4>3>10>8，且不限于单一克隆或血清型的菌株。来自克隆8的8C菌株对大多数测试大肠杆菌素具有抗性。在食品和农业中使用大肠杆菌素抑制包括O157:H7血清型在内的敏感致泻性大肠杆菌菌株具有潜力。
