Evaluation of the relative effectiveness of various antibiotic regimens used to treat hospital-acquired pneumonia induced by drug-resistant Acinetobacter baumannii.

OBJECTIVE

This study aimed to compare the effectiveness of different antimicrobial regimens used in the treatment of hospital-acquired pneumonia caused by extensively drug-resistant Acinetobacter baumannii (XDRAb-HAP).

METHODS

A retrospective analysis was performed using clinical data from 376 patients diagnosed with XDRAb-HAP across four tertiary teaching hospitals in China between January 2017 and May 2022.

RESULTS

The overall 30-day treatment failure rate was 55.1 % (207/376). Multivariate logistic regression identified immunocompromised status, APACHE II score, septic shock, invasive mechanical ventilation, and delayed initiation of definitive therapy as independent predictors of 30-day treatment failure. After adjusting for potential confounders, tigecycline (TGC) monotherapy was associated with a significantly higher risk of 30-day treatment failure compared with polymyxin B (PMB) monotherapy (OR 8.910, 95 % CI 3.211-24.724, p < 0.001). A comparable risk was observed with the PMB plus TGC combination (OR 1.290, 95 % CI 0.619-2.689, p = 0.496). The addition of sulbactam (OR 0.636, 95 % CI 0.276-1.465, p = 0.288) or a carbapenem (OR 1.066, 95 % CI 0.496-2.290, p = 0.871) did not significantly influence the 30-day treatment outcome compared with regimens lacking these agents. Weighted propensity score analyses further supported these associations between treatment regimens and clinical outcomes.

CONCLUSION

In the current therapeutic landscape, lacking effective novel agents, PMB appears to be a reasonable first-line option for managing XDRAb-HAP. However, PMB-based combination therapies did not demonstrate improved clinical efficacy over PMB monotherapy.