Treating carbapenem-resistant Acinetobacter baumannii infections

Antibiotic treatment of patients with carbapenem-resistant Acinetobacter baumannii infection is one of the most controversial issues in the field of difficult-to-treat resistant Gram-negative bacteria management. 1 Paul M Carrara E Retamar P et al. European Society of Clinical Microbiology and Infectious Diseases (ESCMID) guidelines for the treatment of infections caused by multidrug-resistant Gram-negative bacilli (endorsed by European society of intensive care medicine). Clin Microbiol Infect. 2022; 28: 521-547 Summary Full Text Full Text PDF PubMed Scopus (183) Google Scholar , 2 Tamma PD Aitken SL Bonomo RA Mathers AJ van Duin D Clancy CJ Infectious Diseases Society of America guidance on the treatment of AmpC β-lactamase-producing Enterobacterales, carbapenem-resistant Acinetobacter baumannii, and Stenotrophomonas maltophilia infections. Clin Infect Dis. 2022; 74: 2089-2114 Crossref PubMed Scopus (159) Google Scholar Keith S Kaye and colleagues 3 Kaye KS Shorr AF Wunderink RG et al. Efficacy and safety of sulbactam–durlobactam versus colistin for the treatment of patients with serious infections caused by Acinetobacter baumannii–calcoaceticus complex: a multicentre, randomised, active-controlled, phase 3, non-inferiority clinical trial (ATTACK). Lancet Infect Dis. 2023; (published online May 11.)https://doi.org/10.1016/S1473-3099(23)00184-6 PubMed Google Scholar report results of a multinational randomised controlled trial (RCT) assessing the non-inferiority, with a margin of 20%, of sulbactam–durlobactam versus colistin, both given with imipenem–cilastatin, in the treatment of severe carbapenem-resistant A baumannii infections. Overall, 181 patients were randomly assigned and 125 patients (63 in sulbactam–durlobactam group and 62 in colistin group), with microbiological documentation of carbapenem-resistant A baumannii isolates susceptible to study drugs, were assessed for primary efficacy analysis. Non-inferiority was observed with all-cause 28-day mortality rates in the sulbactam–durlobactam group (12 [19%] of 63) and colistin group (20 [32%] of 62; difference –13·2%, 95% CI –30·0 to 3·5). In a second part of the trial, patients with colistin-resistant isolates, or in which colistin use was contraindicated, received sulbactam–durlobactam in an observational framework, confirming good outcome rates. Although these findings could premise a very promising treatment in the management of severe carbapenem-resistant A baumannii infection, some caveats could be raised. Efficacy and safety of sulbactam–durlobactam versus colistin for the treatment of patients with serious infections caused by Acinetobacter baumannii–calcoaceticus complex: a multicentre, randomised, active-controlled, phase 3, non-inferiority clinical trial (ATTACK)Our data show that sulbactam–durlobactam was non-inferior to colistin, both agents given in combination with imipenem–cilastatin, for the primary endpoint of 28-day all-cause mortality. Sulbactam–durlobactam was well tolerated and could be an effective intervention to reduce mortality from serious infections caused by carbapenem-resistant ABC, including multidrug-resistant strains. Full-Text PDF