Efficacy of a Fosfomycin-Containing Regimen for Treatment of Severe Pneumonia Caused by Multidrug-ResistantAcinetobacter baumannii: A Prospective, Observational Study

Introduction Severe pneumonia caused by multidrug-resistantAcinetobacter baumannii(MDR-AB) remains a difficult-to-treat infection. Considering the poor lung penetration of most antibiotics, the choice of the better antibiotic regimen is debated. Methods We performed a prospective, observational, multicenter study conducted from January 2017 to June 2020. All consecutive hospitalized patients with severe pneumonia due to MDR-AB were included in the study. The primary endpoint of the study was to evaluate risk factors associated with survival or death at 30 days from pneumonia onset. A propensity score for receiving therapy with fosfomycin was added to the model. Results During the study period, 180 cases of hospital-acquired pneumonia, including ventilator-associated pneumonia, caused by MDR-AB strains were observed. Cox regression analysis of factors associated with 30-day mortality, after propensity score, showed that septic shock, and secondary bacteremia were associated with death, while a fosfomycin-containing regimen was associated with 30-day survival. Antibiotic combinations with fosfomycin in definitive therapy for 44 patients were: fosfomycin + colistin in 11 (25%) patients followed by fosfomycin + carbapenem + tigecycline in 8 (18.2%), fosfomycin + colistin + tigecycline in 7 (15.9%), fosfomycin + rifampin in 7 (15.9%), fosfomycin + tigecycline in 6 (13.6%), fosfomycin + carbapenem in 3 (6.8%), and fosfomycin + aminoglycoside in 2 (4.5%). Conclusions This real-life clinical experience concerning the therapeutic approach to severe pneumonia caused by MDR-AB provides useful suggestions to clinicians, showing the use of different antibiotic regimens with a predominant role for fosfomycin. Further randomized clinical trials are necessary to confirm or exclude these observations.

Automated summary

Severe pneumonia caused by multidrug-resistant Acinetobacter baumannii remains difficult to treat, and the choice of antibiotic regimen is debated due to poor lung penetration of most antibiotics. A study conducted from 2017 to 2020 found that septic shock and secondary bacteremia were associated with death, while a regimen containing fosfomycin was associated with improved 30-day survival. Different antibiotic regimens, with fosfomycin playing a predominant role, were used in treating the severe pneumonia caused by MDR-AB.