ABSTRACT
While the use of enrichment broths in food and environmental microbiology has been demonstrated, their use in clinical microbiology has fully been established. In some cases, the use of enrichment broths has done little more than add unnecessary cost and extra testing. While most organisms prefer to grow in a neutral pH environment, the pH level can be used as enrichment method. Acidophiles, for instance, can be enriched by lowering the pH in the media. Although researchers usually tend to focus on ingredients that can be added to a liquid medium, it should be remembered that manipulating the physical environment in which the culture is placed for temperature, oxygen tension, even pressure, may offer some microorganisms a competitive advantage in reproduction. Enrichment for specific groups or species of microorganisms only be achieved by defining conditions that will preferentially allow them to grow, but can be achieved through the use of agents that will inhibit the growth of competing organisms.
