The theory and relevance of continuous culture.

Batch cultures of micro-organisms which utilize typical laboratory media, generally result in rapidly dividing cultures (generation times less than 1 h). These are atypical of those found in natural environments. The continuous culture of micro-organisms allows either specific-growth-rate to be controlled, whilst maintaining the cells in a constant physical and chemical environment or a constant specific-growth-rate to be maintained whilst physico-chemical parameters of growth such as pH, temperature or nutrient availability are varied. Continuous culture therefore offers the prospect of in-vitro culture of micro-organisms in physiological states relevant to their natural habitats. This article introduces the concepts of continuous culture and discusses their relevance towards in-vitro models of infection and of antibiotic dosing.