Do you order repeat blood cultures (BC) to confirm negative results in cases of Escherichia coli (E. coli) bacteremia, or is this practice only for gram-positive bacteremia?

From the Research

For E. coli bacteremia, repeat blood cultures to confirm clearance are generally not necessary if the patient is clinically improving on appropriate antibiotic therapy. This approach is supported by the fact that gram-negative bacteremias like E. coli typically respond more predictably to appropriate antibiotics and have lower rates of complicated infections such as endocarditis or metastatic foci compared to gram-positive bacteremias like Staphylococcus aureus 1. However, repeat cultures should be obtained if the patient remains febrile, shows signs of clinical deterioration, or has risk factors for complicated infection such as immunosuppression, prosthetic devices, or endovascular infections.

Some key points to consider in the management of E. coli bacteremia include:

• The choice of antibiotic therapy, with options including ceftriaxone, piperacillin-tazobactam, and meropenem, depending on the susceptibility of the isolate and the clinical context 2, 1.
• The importance of source control, such as drainage of an intra-abdominal abscess, in addition to antibiotic therapy 3.
• The potential for antibiotic resistance, including extended-spectrum beta-lactamase (ESBL) production, and the need for susceptibility testing to guide therapy 4, 5.

In terms of specific recommendations, repeat blood cultures should be obtained in patients with E. coli bacteremia who remain febrile or show signs of clinical deterioration despite appropriate antibiotic therapy, as well as in those with risk factors for complicated infection or who have not had adequate source control 1. However, for patients who are clinically improving on appropriate therapy, repeat blood cultures are not routinely necessary.