Lahiri S S, Karothia B S, Kumar P
Defence R and D Estt, Gwalior, India.
Acta Microbiol Hung. 1993;40(1):59-63.
An attempt has been made to detect the minimum counts of enterotoxigenic Escherichia coli (ETEC) in stool sample under simulated clinical condition. Thermostable (ST-la) enterotoxin-producing ETEC culture was mixed with stool sample and normal saline, centrifuged, then the supernatant was further diluted with saline and different volumes were spotted on nitrocellulose paper. Hybridization with 32P labelled pDAS-101 DNA and viable count of original culture on MacConkey agar plates with ampicillin revealed that minimum 8 cells of ETEC (ST) could be detected. The method of labelling used was sequential harnessing of the catalytic and synthetic activity of the large Klenow fragment of DNA polymerase-I. Linearizing of the DNA was dispensed with as the nicked circular DNA was excised with the gel and used for labelling directly.
已尝试在模拟临床条件下检测粪便样本中产肠毒素大肠杆菌（ETEC）的最小数量。将产热稳定（ST-la）肠毒素的ETEC培养物与粪便样本和生理盐水混合，离心，然后将上清液用盐水进一步稀释，并将不同体积的稀释液点样在硝酸纤维素纸上。用32P标记的pDAS-101 DNA进行杂交以及在含氨苄青霉素的麦康凯琼脂平板上对原始培养物进行活菌计数表明，可检测到的ETEC（ST）的最小数量为8个细胞。所使用的标记方法是依次利用DNA聚合酶I的大片段Klenow的催化和合成活性。由于带切口的环状DNA用凝胶切除并直接用于标记，因此无需对DNA进行线性化处理。
