Tests help aid in antibiotic control

FDA recently approved 2 tests that will aid healthcare providers in determining which antibiotics are needed, leading to better antibiotics management.

FDA approved the PhenoTest BC Kit, performed on the Pheno System (Accelerate Diagnostics), the first test to identify organisms that cause bloodstream infections and provide information about which antibiotics the organism is likely to respond to (antibiotic sensitivity).

The test also reduces the amount of time it takes to provide this important information, which can guide antibiotic treatment recommendations more quickly, according to a FDA statement.

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"By identifying organisms and knowing earlier which antibiotics the organism is likely to respond to, health care professionals can treat patients with bloodstream infections more appropriately," said Alberto Gutierrez, PhD, director of the Office of In Vitro Diagnostics and Radiological Health at the FDA’s Center for Devices and Radiological Health, in the statement.

Bacterial or yeast blood infections can occur in patients of all ages, but are particularly severe in infants, the elderly, and those with weakened immune systems. If not treated rapidly, such bloodstream infections can lead to severe complications, such as septic shock and death.

Unlike traditional identification and antibiotic susceptibility tests, which may take 24 to 48 hours after detection in a positive blood culture to provide test results, the PhenoTest BC Kit can identify bacteria or yeast from a positive blood culture in approximately 1.5 hours. For certain organisms, the test also provides important information to guide treatment recommendations in approximately 6.5 hours after the organisms are detected from blood cultures.
 
The test can identify 14 different species of bacteria and two species of yeast that cause bloodstream infections, while also providing antibiotic sensitivity information on 18 selected antibiotics for a subset of the identified organisms as appropriate. The test will also identify the presence of two indicators of antibiotic resistance, which can occur when potentially harmful bacteria change in a way that reduces or eliminates the effectiveness of antibiotics.

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FDA also cleared the expanded use of the Vidas Brahms PCT Assay (bioMérieux Inc.) to help healthcare providers determine if antibiotic treatment should be started or stopped in patients with lower respiratory tract infections, such as community-acquired pneumonia, and stopped in patients with sepsis.

“Unnecessary antibiotic use may contribute to the rise in antibiotic-resistant infections, Gutierrez said in a FDA statement. “This test may help clinicians make antibiotic treatment decisions.”

The test is the first to use procalcitonin (PCT), a protein associated with the body’s response to a bacterial infection, as a biomarker to help make antibiotic management decisions in patients with these conditions, FDA said.

The test works by measuring PCT since high levels of PCT suggest a bacterial infection, while low levels suggest a viral infection or non-infectious causes. Clinicians may be able to use PCT and other information to safely withhold or stop antibiotics. However, because PCT may indicate the presence of a variety of bacterial infections, it does not detect the exact cause of a patient’s symptoms.

The Vidas Brahms test is intended to be used in the hospital or emergency room. Risks associated with use of the test may include false positive results, which may lead to unnecessary treatment with antibiotics, and false negative results, which may lead to a delay in the selection of appropriate therapy. 

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