The API 20E system is specifically designed for the rapid identification of Gram-negative bacteria, primarily targeting members of the Enterobacteriaceae family.
Understanding API 20E's Purpose
The Analytical Profile Index (API) 20E system is a widely utilized biochemical test panel for microbiological laboratories. Its core function is to facilitate the swift and accurate identification of specific bacterial groups based on their metabolic characteristics. This diagnostic tool employs a series of miniature test wells, each containing a dehydrated substrate that detects a particular enzymatic activity or fermentation reaction.
Target Organisms of API 20E
The API 20E system is specifically tailored to identify Gram-negative bacteria, with a primary focus on the Enterobacteriaceae family. This family includes a broad range of clinically significant bacteria commonly found in the intestines of humans and animals.
- Gram-negative bacteria: These are bacteria that do not retain the crystal violet stain in the Gram staining procedure due to their unique cell wall structure. They are a large and diverse group, many of which can cause infections in humans.
- Enterobacteriaceae: This is a large family of Gram-negative bacteria that includes many well-known genera. They are typically facultative anaerobes and are often associated with various infections, including urinary tract infections, bloodstream infections, and gastrointestinal illnesses.
Common genera within the Enterobacteriaceae family that API 20E helps identify include, but are not limited to:
- Escherichia (e.g., E. coli)
- Klebsiella (e.g., K. pneumoniae)
- Enterobacter
- Citrobacter
- Proteus
- Salmonella
- Shigella
- Serratia
- Yersinia
API 20E vs. API 20NE
It's important to note that while API 20E targets Enterobacteriaceae, there's a related system called API 20NE which is designed for the identification of Gram-negative bacteria that are non-Enterobacteriaceae. Together, these systems provide a comprehensive approach to identifying a wide spectrum of Gram-negative organisms.
| API System | Primary Target Group | Characteristics |
|---|---|---|
| API 20E | Enterobacteriaceae | Gram-negative, facultative anaerobic rods, commonly intestinal pathogens |
| API 20NE | Non-Enterobacteriaceae | Gram-negative, typically aerobic or microaerophilic rods (e.g., Pseudomonas, Acinetobacter species) |
For more detailed information on the Analytical Profile Index systems, you can refer to resources like Wikipedia.
