Optimum treatment strategies for carbapenem-resistant Acinetobacter baumannii bacteremia

Abstract

Carbapenem-resistant Acinetobacter baumannii (CRAB) constitutes an increasing problem worldwide. CRAB bacteremia is associated with a high fatality rate and its optimal treatment has not been established. Early institution of appropriate therapy is shown to improve survival of patients with CRAB bloodstream infection. Regrettably, treatment options are limited. Little information exists about the efficacy of sulbactam for the treatment of CRAB bacteremia. Colistin and tigecycline possess good in vitro activity and represent in many cases the only therapeutic options although clinical data are scarce. The need for a loading dose of colistin has been recently demonstrated to rapidly achieve therapeutic levels. The use of combination therapy is also a matter of debate but current evidence do not support its routine use.

Keywords:

• Acinetobacter baumannii
• bacteremia
• carbapenem-resistant
• colistin
• polymyxin
• tigecycline
• treatment

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Early institution of appropriate antimicrobial therapy is shown to improve survival of patients with CRAB bacteremia.

• Carbapanem should not be used at least in monotherapy in the empirical therapy of CRAB bacteremia in areas with high rate of resistance to carbapenems.

• Colistin is the most appropriate option in the empirical treatment of patients with high suspicion of CRAB bacteremia.

• A loading dose of 6–9 MU of colistin is necessary in all patients independently of their renal function to achieve adequate plasma levels in the first 24 h.

• Maintenance dose should be individually adjusted according to creatinine clearance. With creatinine clearance above 50 ml/min, maintenance doses of 9 MU every day (divided in two or three doses) should be administered.

• For patients undergoing continuous renal replacement therapy, a daily dose of 9 MU of colistin is suggested.

• Tigecycline is not a suitable option for CRAB primary bacteremia. If no other alternative is available or they are contraindicated due to toxicity, a high-dose regimen (loading dose 200 mg followed by 100 mg every 12 h) should be administered.

• Combination therapy should not be routinely used in the directed therapy for CRAB bacteremia. The decision should be individualized in each patient depending of the clinical situation and the MIC of the isolated strain.

Notes

Adapted from references [5,7,11].