Klebsiella pneumoniae and Proteus mirabilis are examples of bacteria that are considered citrate positive. This characteristic indicates their ability to utilize citrate as their sole carbon and energy source for growth.
Understanding Citrate Utilization
Bacteria are classified as citrate positive or citrate negative based on their ability to grow on a medium where citrate is the only available carbon source. This is commonly assessed using Simmons Citrate Agar, a differential medium. When a bacterium can metabolize citrate, it produces alkaline byproducts, leading to a visible color change in the medium from green to blue. This blue color signifies a positive result, indicating the bacterium is citrate positive.
Examples of Citrate Positive and Negative Bacteria
The citrate utilization test is a crucial biochemical test used in microbiology, particularly for differentiating Gram-negative rods within the family Enterobacteriaceae.
| Citrate Positive Bacteria | Citrate Negative Bacteria |
|---|---|
| Klebsiella pneumoniae | Escherichia coli |
| Proteus mirabilis | Shigella dysenteriae |
Importance in Bacterial Identification
- Differentiation: The citrate test helps distinguish between closely related bacterial species that may appear similar in other tests. For instance, it can help differentiate Klebsiella pneumoniae (citrate positive) from Escherichia coli (citrate negative).
- Clinical Relevance: Identifying bacteria accurately is vital in clinical settings for diagnosing infections and guiding appropriate treatment, as different species may respond to different antibiotics.
