Daptomycin-Induced Eosinophilic Pneumonia: A Case Report and Systematic Review.

Introduction: Acute eosinophilic pneumonia (AEP) is a rare respiratory condition caused by eosinophil accumulation in the pulmonary tissue that can be related to drug administration. Daptomycin, an antibiotic active against gram-positive bacteria, is one of the leading causes of AEP among drugs. In order to raise awareness of this rare syndrome, in our work we have described a case of an 82-year-old male with Enterococcus faecalis endocarditis treated with daptomycin, who developed a daptomycin-induced AEP. We have performed a systematic review of the literature for all similar reported cases.

Methods: The systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. To conduct the analysis, the terms "daptomycin AND eosinoph* AND pneum*" were entered into the databases Medline, CINAHL, and Embase on April 13, 2023. We considered all relevant records documenting AEP after daptomycin use. No restrictions in terms of year or language were made. A formal appraisal of observational studies was performed by Newcastle-Ottawa Scale. All results and data were reported by means of tables.

Results: Our search identified 93 relevant records, published between 2007 and 2023. A total of 120 patients were considered. Patients who experienced AEP were mostly males (n = 88, 73.3%) with a mean age of 68.28 years (SD 11.54). Daptomycin was most frequently prescribed for osteoarticular infections (n = 75, 62.5%) and to treat gram-positive cocci infections. The most frequently isolated pathogen was methicillin-resistant Staphylococcus aureus. Daptomycin was mostly used with off-label indications (n = 89, 74%). Symptoms of AEP were usually reported after a mean of 21.75 days of treatment (range 3-84) and typically included fever, dyspnea, dry cough, and acute respiratory failure. Reported treatment strategies invariably included daptomycin withdrawal, respiratory support, and corticosteroid treatment. One hundred and sixteen patients fully recovered. A fatal outcome was described in 4 patients. Suggestive symptoms and imaging raised suspicion for AEP, confirmed with bronchoalveolar lavage in 57.5% of the cases.

Discussion and conclusions: Daptomycin-induced AEP is a rare but potentially fatal complication, mostly reported after long treatment with daptomycin. Clinicians should be aware of this syndrome, as it could be initially misdiagnosed for an acute infectious respiratory syndrome, resulting in a delay in its diagnosis and treatment. Furthermore, since the risk of developing AEP is increased by longer drug exposure, caution should be used when discussing the use of daptomycin in longer treatment regimens.