Improvement of the polymerase chain reaction to detect Escherichia coli Shiga-like toxin II gene from clinical isolates

Abstract

The polymerase chain reaction was improved to detect Escherichia coli Shiga-like toxin II gene from clinical isolates. Concentrations of bacterial DNA, primers SLT-II1 and SLT-II2, and MgCl 2 were modified up to obtain the cleanest electrophoretic pattern and the highest yield of SLT-II amplimer. T m was calculated using the formulae 2(A + T) + 4(G + C) and %(G + C), although the best results were obtained with the latter. The sample preparation method and the experimental conditions established were applicable to E. coli strains isolated from clinical samples, allowing a rapid, sensitive and more specific screening.