Abstract |
An experimental procedure was developed to study the association of selected bacteria and macroinvertebrates and their response to free available chlorine disinfection. The organisms selected for study were Escherichia coli (LacZ545), Enterobactercloacae (ATCC 23355), and the amphipod Hyalella azteca. E. coli was shown to bind tightly (16,000 CFU per amphipod) to the macroinvertebrate and to resist repeated attempts to wash it off. E. cloace was shown to bind much less tightly (1,400 CFU per amphipod) to H. azteca and was less resistant to removal by washing. The extent of association is a function of macroinvertebrate size (surface area), but the procedure produces repeatable results usable for controlled experimentation. The method, together with the dual bacterial identification criteria (morphology and antibiotic resistance), was used to study the response of unassociated and associated E. coli and E. cloacae to disinfection with free available chlorine at 1.0 mg/liter. (Copyright (c) 1984, American Society for Microbiology.) |