Antibiogram (Antibiotic Susceptibility Test)
Definition
Determines which antibiotic will be most effective in treating your infection. The test requires a culture to be performed first: once the culture has grown the causative organism (bacteria or fungus), that sample is tested against various antibiotics.
Purpose
For bacterial or fungal infections that are resistant to standard treatment. Common indications: tuberculosis, MRSA and C. difficile infections, and situations in which conventional antibiotics have failed.
Results
There are three categories, and the report uses these terms:
| Category | Meaning |
|---|---|
| Susceptible | The antibiotic killed the microorganism, a usable treatment option |
| Intermediate | The drug may work at a higher dose or with more frequent administration |
| Resistant | The antibiotic did not stop the growth of, or kill, the bacteria or fungus causing the infection |
Normal Values
Not applicable, the result is reported categorically.
Risks and Limitations
Resistant infections may require combination therapy.
Its importance for antibiotic resistance: when bacteria stop responding to standard drugs, identifying effective alternatives prevents previously treatable infections from turning into serious or life-threatening complications.