High-dose sulbactam for extensively drug-resistant Acinetobacter baumannii infection in patients with critical illness.

Objectives

The therapeutic effect and tolerability of sulbactam, at a daily dose of at least 9 g, were assessed in critically ill individuals who acquired extensively drug-resistant Acinetobacter baumannii (XDR-AB) infection.

Methods

This single-center retrospective cohort evaluated a primary composite endpoint of death from any cause or invasive mechanical ventilation (IMV) within 28 days. Secondary endpoints comprising the 14-day composite outcome, IMV-free and ICU-free days through day 28.

Results

The study cohort comprised 114 patients diagnosed with XDR-AB infection, of whom 72 (63.2%) received high-dose SBT-containing therapy. The high-dose SBT group showed a lower incidence of the composite outcomes, a higher IMV-free rate, and more IMV-free days through 28 days, with consistent results after adjustment using inverse probability of treatment weighting (IPTW) or the overlap weighting (OW) approach. The observed association of high-dose SBT did not differ significantly by concomitant antibiotic regimen. Within-regimen analysis showed that patients receiving polymyxin B plus high-dose SBT had more IMV-free days through day 28 (mean difference 4.0 days, P = 0.025). No increased signal of nephrotoxicity, hepatotoxicity, or other SBT-related adverse events was observed during the 7-day monitoring period.

Conclusions

With both high-dose and low-dose SBT combined with comparable antimicrobial regimens, the high-dose group was associated with potentially better outcomes, with no increased signal of adverse events. The observed association was independent of concomitant antibiotic choice, with more IMV-free days in the polymyxin B subgroup. These findings suggest high-dose SBT could serve as a therapeutic option in patients with critical illness who have XDR-AB infection.