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T2Bacteria Positive while Cultures Remained Negative

An elderly patient presented to the ED with nausea, myalgia, and insomnia.


This case highlights the benefit of the T2Bacteria Panel’s ability to provide species identification in the presence of antimicrobial therapy rapidly.  Using T2Bacteria enabled the identification of E.coli in a patient on inadequate therapy for a urinary tract infection (UTI).


An elderly patient presented to the ED with nausea, myalgia, and insomnia. The patient had seen their primary care provider earlier in the day and was given a three-day course of antibiotics for a suspected UTI.  Once in the ED, the patient received IV fluids and antiemetics. At that time, blood cultures and a T2Bacteria Panel were drawn. The patient began to feel better a short time later and was discharged home. They were believed to have had a viral syndrome and were told to stop taking the antibiotics.

Evaluation and Treatment Decision

The patient was on an oral course of antimicrobials for a suspected UTI but was told to discontinue them after an ED visit.

T2Bacteria Panel Result

Positive for E.coli

Blood Cultures

No growth

Urine Cultures

No growth

Hospital course and decision making based on the T2Bacteria Panel result

After the patient was discharged, the T2Bacteria resulted and was positive for E.coli.  The patient was called but did not return the phone call until the next day.  Upon returning the call, they stated that they were feeling worse and were asked to return to the ED at that time.  The patient was started on IV ceftriaxone upon admission and transferred to the floor.  Blood cultures and urine cultures remained negative to date.

In this case, T2Bacteria picked up the E.coli infection from the suspected genitourinary infection, but it was never detected in blood or urine culture due to the previous administration of antimicrobials.  Approximately 36 hours later, the patient was discharged and sent home on oral antimicrobials to complete a standard course of 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