Detection of Polymicrobial Infections Using T2Bacteria

The patient presented to the emergency department with flu-like symptoms


This case highlights the ability of the T2Bacteria® Panel to provide rapid species identification of causative pathogens in sepsis cases. It examines clinical challenges with current methods, including delayed blood culture growth, as well as polymicrobial infections. A rapid T2Bacteria result could have allowed for more informed treatment decisions, including earlier initiation of antibiotic therapy and earlier admission to the hospital.


The patient presented to the emergency department with flu-like symptoms, but at the time, clinical status and workup did not warrant admission. The patient continued to decline and re-presented to the emergency department approximately 18 hours later with shortness of breath. While in the emergency department during the second visit, the blood cultures that were obtained during the earlier visit resulted positive with gram-negative rods, and the prescriber was notified. The patient was subsequently admitted, and empiric antibiotics were initiated.

Patient Selection Criteria

Procalcitonin 10.21

Evaluation and Treatment Decision



T2Bacteria Result

(sample obtained during initial ED visit): Positive for Pseudomonas aeruginosa and E. coli

Blood culture #1 Result

(obtained during initial ED visit): Pseudomonas aeruginosa and Serratia marcescens
(time to culture positivity: 20.5 hours; time to species ID: ~2.5 days for P. aeruginosa and ~5 days for S. marcescens).

*Note: Verigene assay was performed after detection of the growth of gram-negative rod on the culture. It was positive for the detection of Klebsiella oxytoca only and not the pathogens that grew in blood culture.

Blood culture #2 Result

(obtained during second ED visit): E. coli
(time to culture positivity: 24 hours; time to species ID: ~1.5 days)

Empiric Therapy


Decision making based on T2Bacteria Result

Note: T2Bacteria results were not reported as this case was part of an observational study.

The blood cultures that were obtained from the patient upon initial presentation had delayed the growth of gram-negative rods, which were found 22 hours later. The patient was discharged from the emergency department prior to blood culture resulting in positive for growth. The patient continued to decline and re-presented to the emergency room, requiring subsequent admission to the hospital.

Had the T2Bacteria test been performed, and the result been reported immediately after collection, the patient could have potentially avoided the premature discharge from the emergency department and earlier initiation of effective antibiotic therapy.

According to the CDC, of the 154 million prescriptions for antibiotics written in doctors’ offices and emergency departments each year, 30% are unnecessary.12