Could the water have a high concentration of the pathogenic bacterium Vibrio cholera and give negative results in the multiple-tube technique? Briefly explain___ Why are coliforms used as indicator organisms if they are not usually pathogens? Why isn’t a pH indicator needed in the lactose broth fermentation tubes? If coliforms are found in a water sample, the IMViC tests will help determine whether the coliforms are of fecal origin and not from plants or soil. What IMViC results would indicate the presence of fecal coliforms? ____