Treatment of Acinetobacter Infections

Mechanisms of Resistance and Treatment Recommendations

Acinetobacter species demonstrate intrinsic resistance to ceftazidime-avibactam, primarily due to intrinsic production of OXA-type carbapenemases (class D) that are not effectively inhibited by avibactam, according to the International Journal of Antimicrobial Agents 1, 2
For CRAB (Carbapenem-Resistant Acinetobacter baumannii) infections, guidelines recommend Tigecycline-based combination therapy or polymyxin-based combination therapy as preferred options, with selection between these regimens based on patient-specific factors such as renal function and hepatic function, as suggested by the Journal of Microbiology, Immunology and Infection 3, 4
The Infectious Diseases Society of America recommends avoiding polymyxins in renal insufficiency and using tigecycline cautiously with liver impairment for CRAB infections 3

Ceftazidime-avibactam is highly effective against KPC-producing Carbapenem-Resistant Enterobacterales (CRE) and OXA-48-like producing CRE, according to the International Journal of Antimicrobial Agents 1, 2
Ceftazidime-avibactam combined with aztreonam shows significant efficacy against Metallo-β-lactamase (MBL) producing CRE, including NDM and VIM producers, with demonstrated lower 30-day mortality (HR: 0.37, 95% CI 0.13-0.74) and lower clinical failure rates compared to other antimicrobial therapies, as reported by the Journal of Microbiology, Immunology and Infection 5, 6

For severe Acinetobacter infections, clinicians should focus on agents with demonstrated activity and consider combination therapy approaches with agents like polymyxins, tigecycline, or other locally active agents based on susceptibility testing, as recommended by the Journal of Microbiology, Immunology and Infection 3, 4