FDA clears first rapid blood test for MRSA

Jan 3 2008

The U.S. Food and Drug Administration (FDA) has announced it has cleared for marketing the first rapid blood test for the drug-resistant staph bacterium known as MRSA (methicillin-resistant Staphylococcus aureus), which can cause potentially deadly infections.

Methicillin is an antibiotic that has been used successfully to treat infections from the Staphylococcus aureus bacterium. Over the years, the staph bacterium mutated and spawned MRSA, a strain of staph bacterium that is resistant to methicillin and which has a higher rate of being fatal.

The BD GeneOhm StaphSR Assay uses molecular methods to identify whether a blood sample contains genetic material from the MRSA bacterium or the more common, less dangerous staph bacterium that can still be treated with methicillin.

“The BD GeneOhm test is good news for the public health community. Rather than waiting more than two days for test results, health care personnel will be able to identify the source of a staph infection in only two hours, allowing for more effective diagnosis and treatment,” said Daniel G. Schultz, M.D., director, FDA's Center for Devices and Radiological Health.

Staph infections occur most frequently among persons in hospitals and health care facilities (such as nursing homes and dialysis centers) who have weakened immune systems. Both types of bacteria also can infect healthy people.

Distinguishing between the two sources of infection is critical to successful treatment.

The more common, less dangerous strain of staph results in infections that are generally mild and affect the skin with pimples or boils that can be swollen, painful and drain pus.

However, the MRSA staph bacterium is difficult to treat with ordinary antibiotics. It can cause potentially life-threatening conditions such as blood stream infections, surgical site infections or pneumonia.

FDA cleared the BD GeneOhm StaphSR assay based on the results of a clinical trial at five locations. The new assay identified 100 percent of the MRSA-positive specimens and more than 98 percent of the more common, less dangerous staph specimens.

In order to preserve the integrity of positive test results, this test should be used only in patients suspected of a staph infection. The test should not be used to monitor treatment for staph infections because it cannot quantify a patient's response to treatment. Test results should not be used as the sole basis for diagnosis as they may reflect the bacteria's presence in patients who have been successfully treated for staph infections. Also, the test will not rule out other complicating conditions or infections.