Cefotetan Therapy for Escherichia Coli Infections

Inclusion Criteria (clinical cohort):

* Identified within 72 hours of inpatient antibiotic administration for acute illness.
* Patient or legally authorized representative are able to provide informed consent for participation in the study.
* Monomicrobial E. coli bacteremia.
* Isolate susceptible to both ertapenem and cefotetan (ESBL infections) or ceftriaxone and cefotetan (non-ESBL infections).

Exclusion Criteria (clinical cohort):

* Allergy to cefotetan.
* History of cephalosporin-associated hemolytic anemia.
* Allergy to ertapenem or meropenem (among patients with ESBL E. coli infections).
* Allergy to ceftriaxone (among patients with non-ESBL E. coli infections). Includes allergy to antibiotics with a similar structure expected to confer cross reactivity to ceftriaxone (cefotaxime, cefpodoxime, ceftazidime).
* Any bacteremia with the same organism in the previous 30 days.
* Pregnant or breastfeeding.
* Neutropenia (absolute neutrophil count \<500 cells/microL), current or anticipated during acute illness.
* Stem cell transplant or hematologic malignancy receiving chemotherapy.
* Severe illness, including shock and/or intensive care unit admission.
* Inability to complete at least 72 hours of appropriate parenteral therapy, including at least 1 dose cefotetan for patients randomized to the treatment arm or at least 1 dose of appropriate parenteral therapy following randomization for patients assigned to the standard of care arm.