What should be monitored by automated blood culture incubators?

Automated blood culture incubators are designed to monitor specific parameters that indicate microbial growth in blood samples. The monitoring of carbon dioxide production is particularly critical because it serves as an indicator of metabolic activity from any bacteria present in the cultures. As bacteria grow, they metabolize nutrients and produce carbon dioxide, which can be detected as an increase in the level of carbon dioxide in the culture environment. This is a key sign that the culture is positive for bacterial growth.

In contrast, while bacterial shape and size might be assessed during microscopic examination after culturing, the incubators themselves do not monitor these parameters. Temperature fluctuations are important for the general functioning of biological processes but are typically kept constant in the incubators rather than actively monitored as a primary indicator of growth. Similarly, oxygen levels can be relevant in certain types of cultures, especially for anaerobic or facultative anaerobic bacteria; however, the primary automation in these incubators focuses on the detection of CO2 as an indicator of growth, making it the most pertinent parameter to monitor for assessing microbial activity during incubation.