Evidence indicates that early institution of appropriate antibiotics is a crucial determinant of improved outcomes in patients with sepsis and bloodstream infections (BSIs). However, “blood cultures, the gold standard for diagnosing BSI, are insensitive and limited by prolonged time to results,” explains M. Hong Nguyen, MD. “For these reasons, development of rapid non-culture diagnostic tests for BSIs is a top priority.”
The T2Bacteria panel is the first direct-from-blood, nonculture test cleared by the FDA for diagnosis of BSI. The panel detects within 4-6 hours the five most common ESKAPE bacteria (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa and Escherichia coli), that are frequent causes of hospital infection and which are often multi-drug resistant.
To determine the performance of T2Bacteria in diagnosing BSIs, Dr. Nguyen and colleagues conducted a prospective study of more than 1,400 patients with suspected sepsis in whom blood cultures were ordered at 11 U.S. hospitals. After informed consent was obtained, the study team drew paired blood culture and T2Bacteria samples for testing. Performance of T2Bacteria was compared with a single set of blood cultures in diagnosing proven, probable, and possible BSIs caused by T2Bacteria-targeted organisms.
“Our study shows that the T2Bacteria panel rapidly and accurately diagnosed and identified ESKAPE bacterial BSIs, and identified probable and possible BSIs that were missed by blood cultures (in particular among patients who were already receiving antibiotics),” says Dr. Nguyen. Indeed, mean times to species identification with T2Bacteria were 3.61 to 7.70 hours, depending on the number of samples tested, compared with 71.7 hours for blood culture. For proven BSIs, T2Bacteria had per-patient sensitivity and specificity of 90%, with a negative predictive value of 99.7%.
“Physicians should understand the advantages and limitations of T2Bacteria panel,” suggests Dr. Nguyen. “The panel should be used in conjunction with blood cultures, in order to provide the best likelihood of diagnosing the cause of BSI. Integrating the T2Bacteria panel into clinical practice will provide opportunities to enhance patients’ management, but the best use of the test will be in coordination with antimicrobial stewardship teams to assure that results are interpreted quickly and incorporated into real-time decision making.”