Final answer:
A candle jar provides the required increased concentration of CO₂ and decreased oxygen concentration that capnophilic bacteria like Brucella need to grow, which is achieved as the candle burns and consumes oxygen.
Step-by-step explanation:
Usage of Candle Jar for Culturing Brucella
A candle jar is used to grow Brucella because it is a capnophilic bacterium that prefers a higher concentration of CO₂ and a lower concentration of oxygen than that of the atmosphere. To simulate this environment, the candle jar method involves placing the cultures into the jar, lighting a candle inside, and then sealing the jar. As the candle burns, it consumes oxygen, creating an environment with increased CO₂ levels which is conducive to the growth of Brucella and other capnophiles.
This method is essential for the cultivation of Brucella in a lab setting, as it mimics the conditions this bacteria might encounter within a host organism. Culturing Brucella is challenging due to its need for specific growth conditions and because it is classified as a BSL-3 pathogen, meaning it requires stringent laboratory safety procedures to handle.