Interactions of the Oral Microbiota I. A System for the Defined Study of Mixed Cultures. ∗

Abstract

Summary

A continuous 2-stage system for investigations of interactions between 2 or more species of bacteria is described. The system employs 2 or more chemostatically limited stages of pure cultures feeding to a non-limited mixed continuous growth cell. This permits comparison at any point on the growth curve of numbers and products of organisms in pure culture with numbers and metabolic products resulting from interactions between the same organisms in growing in mixed culture. The systems are mathematically defined and the data can be expressed in generation time. Results obtained with a mixture of S. salivarius and V. alcalescens indicate a distinct interaction betwen the strains employed. Generation time of each of these species was noticeably increased while growing in context with the other.