Treatment of Multidrug-Resistant Acinetobacter baumannii Infections

Primary Treatment Algorithm by Infection Site

The American College of Physicians recommends using intravenous colistin-based combination therapy as first-line treatment for multidrug-resistant Acinetobacter baumannii infections, with specific regimens determined by infection site and severity 1, 2
For pneumonia, the Infectious Diseases Society of America recommends colistin IV (loading dose 5 mg CBA/kg, then maintenance 2.5 mg CBA × [1.5 × CrCl + 30] q12h) PLUS a carbapenem (meropenem 2g IV q8h or imipenem 500mg IV q6h) PLUS adjunctive inhaled colistin for at least 7 days 3, 1, 2
The duration of treatment for HAP/VAP is 10-14 days 2
For bloodstream infections, the American College of Physicians recommends colistin IV (same dosing as above) with or without carbapenem for 10-14 days 1, 2
The American College of Physicians also recommends extending treatment to 2 weeks if severe sepsis or septic shock is present 2

The FDA recommends using a loading dose of colistin even in renal impairment, as skipping it can cause 2-3 days of subtherapeutic levels and increase mortality 2
The FDA also recommends monitoring renal function closely due to the risk of nephrotoxicity (33-39%) 2
The Infectious Diseases Society of America recommends using sulbactam 9-12 g/day in 3-4 divided doses, administered as 4-hour infusions, only if MIC ≤4 mg/L by Etest 4, 1, 2

The American College of Physicians recommends using sulbactam-based therapy (9-12 g/day) as preferred first-line treatment for patients with renal impairment when MIC ≤4 mg/L to preserve kidney function 2
The American College of Physicians also recommends avoiding tigecycline monotherapy due to poor outcomes 1, 2

The Infectious Diseases Society of America recommends never using tigecycline as monotherapy for pneumonia or bloodstream infections due to poor outcomes and very low lung concentrations (0.01-0.02 mg/L) 3, 1
The Infectious Diseases Society of America also recommends never using aminoglycoside monotherapy for pneumonia 3

The American College of Physicians recommends monitoring renal function essential throughout colistin therapy 2
The American College of Physicians also recommends assessing clinical response at 48-72 hours and adjusting based on susceptibilities 1
The Infectious Diseases Society of America recommends infectious disease consultation highly recommended for all MDR Acinetobacter infections 1