Efficacy of Fosfomycin-Containing Regimens for Treatment of Bacteremia Due to Pan-Drug Resistant Acinetobacter baumannii in Critically Ill Patients: A Case Series Study.

Acinetobacter baumannii (AB) has evolved over the last decades as a major problem in carbapenem-resistant gram-negative nosocomial infections, associated with high mortality rates especially in the intensive care unit (ICU). Recent reports highlight the increasing prevalence of resistance to colistin, a last resort therapeutic option for carbapenem-resistant AB. We retrospectively evaluated the characteristics, treatment regimens and outcomes of twenty patients with pan-drug resistant (PDR) AB primary bacteremia hospitalized in the ICU of the University General Hospital of Patras, during a two-year period (October 2020-September 2022). The 28-day mortality reached 50%. Between survivors and non-survivors, no differences were found regarding age, gender, and Charlson comorbidity index (CCI). However, non-survivors had higher APACHE II scores and higher prevalence of septic shock and COVID-19 infection. A significantly higher percentage in the survivor group received Fosfomycin as part of the combination regimen. Inclusion of fosfomycin in the combination therapeutic regimen was associated with significantly better survival as compared to non-fosfomycin-containing regimens. In view of the increasing prevalence of PDR-AB infections in ICUs, its associated high rates of mortality and the lack of effective treatment options, the observed survival benefit with fosfomycin inclusion in the therapeutic regimen merits further validation in larger prospective studies.

Triple combination therapy with high-dose ampicillin/sulbactam, high-dose tigecycline and colistin in the treatment of ventilator-associated pneumonia caused by pan-drug resistant Acinetobacter baumannii: a case series study.

Acinetobacter baumannii has evolved in recent decades as a major problem in carbapenem-resistant gram-negative nosocomial infections, associated with high mortality rates especially in intensive care units (ICUs). Recent reports highlight the increasing prevalence of resistance to colistin, a last resort therapeutic option for carbapenem-resistant A. baumannii. We retrospectively evaluated the potential efficacy, in terms of clinical and microbiological cure and mortality, of a combination of intravenous colistin and high-dose ampicillin/sulbactam and high-dose tigecycline, concurrently administered with inhaled colistin, in 10 ICU patients with ventilator-associated pneumonia (VAP) caused by carbapenem- and colistin-resistant A. baumannii strains, with high tigecycline MICs > 2µg/mL. Nine patients (90%) exhibited a successful clinical outcome, accompanied by microbiological eradication in seven of them. All clinically cured patients survived at 14 and 28 days. Acute kidney injury (AKI) was observed in one patient. In view of the increasing prevalence of pan-drug resistant A. baumannii infections in ICUs, its associated high rates of mortality and the lack of effective treatment options, we feel that there is an emerging need for our results to be further validated in larger prospective studies.