Algorithm for empiric antimicrobial selection for gram-negative bacillary bacteremia

ESBL: extended-spectrum beta-lactamases.
* Immunocompromising conditions include: poorly controlled diabetes mellitus, chronic high-dose corticosteroid use, use of other immunosuppressive agents, neutropenia, advanced HIV infection, B or T leukocyte deficiency.
¶ Health care exposures include: hospitalization, hemodialysis, residence in a long-term care facility, and intravenous antibiotic use or chemotherapy.
Δ Empiric therapy should be further tailored based on additional history, prior history of multidrug-resistant gram-negative pathogens, and likely source of infection. As an example, a carbapenem (imipenem, meropenem, or doripenem) is preferable for a patient with a history of infection with ESBL-producing organisms within the prior six months. Alternatively, for a patient with gram-negative bacteremia in the setting of cholangitis, a beta-lactam/beta-lactamase inhibitor or a carbapenem may be preferable to provide anaerobic coverage. For patients with sepsis or septic shock, broad-spectrum gram-positive coverage is often also used until cultures have been finalized. Drug dose lists are for adult patients with normal renal function. Refer to other UpToDate content for options for patients with severe beta-lactam allergies.
◊ For patients with gram-negative bacillary bacteremia and septic shock, we favor a prolonged infusion dosing strategy for most beta-lactams. We suggest not using a prolonged infusion strategy with doripenem because of potential safety issues based on limited data. Refer to other UpToDate content on prolonged infusions of beta-lactam antibiotics.
§ When there is risk of drug-resistant P. aeruginosa, we favor tobramycin or amikacin over gentamicin. Aminoglycoside dosing depends on the patient's weight and creatinine clearance. Dosing adjustments should be based upon the results of serum drug concentration monitoring. Refer to other UpToDate content on aminoglycoside dosing.