Final answer:
The BACTEC automated blood culture system uses sensors to detect the rise in CO2 levels produced by microorganisms, indicating their presence in a blood sample. The specific type of sensor is not detailed, but common types include colorimetric or fluorescent sensors.
Step-by-step explanation:
The BACTEC automated blood culture system detects the presence of microorganisms in a blood sample by monitoring increases in carbon dioxide (CO2) levels, which are produced as a result of microbial metabolism. The system uses specific sensors to detect changes in CO2 concentration within the culture vials. Although the exact type of sensor used in BACTEC is not provided, sensors typically found in such systems are either colorimetric sensors, which change color in response to CO2, or fluorescent sensors that emit a fluorescent signal when CO2 is present. It is important to monitor CO2 because it is a byproduct of organisms as they take in oxygen and carry out metabolic reactions.
For reference, other systems use panels of biochemical reactions and various physiological properties, including pH and chemical sensitivity, to identify microorganisms. Similar to how the BACTEC system functions, changes in pH or CO2 levels due to microbial activity can be monitored and provide crucial information for identifying the types of cells present in the sample. An understanding of CO2 production and its measurement is also fundamental in understanding bodily functions, such as the regulation of respiratory rate by the autonomic nervous system and the response to changes in CO2 concentrations by blood sensors and chemoreceptors.