Long-term preservation of the enteroinvasive Escherichia coli factor responsible for experimental keratoconjunctivitis.

The factor responsible for experimental keratoconjunctivitis (EKC) can be successfully preserved in enteroinvasive Escherichia coli (EIEC) strains for decades. In this respect an adequate freeze-drying technique is essential, whereas the question of protective media appears to be of less importance. The preservation of EKC-producing factor may be associated with the maintenance of some other related properties.