Antimicrobial Resistance Testing for Known Bacteria (Drug Susceptibility)

Why This Test Is Done

Your doctor may order this test if you’ve had recent antibiotic treatments and are experiencing symptoms that suggest a resistant infection, such as persistent fever or worsening illness despite prior treatment. It’s also used in cases where infections are difficult to control or recur.

What to Expect Before the Test

No special preparation is typically needed. The test may involve collecting a blood sample, urine sample, or other bodily fluid depending on the suspected infection site. Always follow your healthcare provider’s instructions for sample collection.

What the Test Results Mean

Results show whether the bacteria in your sample are resistant to the antibiotics you’ve previously used. If resistance is found, your doctor will adjust your treatment plan to use different antibiotics that are more effective against those bacteria.

Common Causes of Resistance

Antibiotic resistance often develops when bacteria are exposed to antibiotics repeatedly or improperly. This can happen if antibiotics are taken for too short a time, not taken correctly, or if they’re prescribed unnecessarily. Sharing antibiotics with others or taking leftover antibiotics can also contribute to resistance.