Significance of low-temperature growth associated with the fecal coliform response, indole production, and pectin liquefaction in Klebsiella

Publisher Website
Google Scholar
Abstract
In the genus Klebsiella, the growth respnse in nutient broth at 10 degrees C correlates inversely with the operational definition of a fecal coliform and not merely with the ability to grow at 44.5 degrees C. Of the fecal coliform-positive Klebsiella, 97% did not grow at 10 degrees C after 72 h of incubation. Conversely, 97% of the fecal coliform-negative isolates grew at 10 degrees C. The amount of growth at 10 degrees C varied among the fecal coliform-negative isolates and was found to correlate with indole production and pectin liquefaction. Low-temperature growth associated with specific biochemical tests can be used to differentiate several groups in the genus Klebsiella. Three main groups were discerned. Group I consists of indole-negative, pectin-nonliquefying, fecal coliform-positive isolates that do not grow at 10 degrees C. Group II isolates are differentiated from group I by a fecal-coliform-negative response and growth at 10 degrees C. Group III are indole-positive, pectin-liquefying, fecal coliform-negative isolates that grow at 10 degrees C. In our culture collection, isolates of group I are most frequently of human/animal clinical origins, whereas isolates of groups II and III are predominantly derived from the environment.