Daptomycin Induced Eosinophilic Pneumonia

Introduction: Daptomycin is an antibiotic approved by FDA in 2003 with an excellent coverage for Gram positive cocci including methicillin resistant Staph. Aureus and vancomycin resistant Enterococci.Acute Eosinophilic Pneumonia(AEP) is a rare but potentially fatal complication of daptomycin is characterized by febrile illness, Hypoxemia,Diffuse Bilateral pulmonary infiltrates and BAL with >25% eosinophils. Case Report: 79 Y/O M with the CKD stage 4 and hypertension presented to the hospital with fever, dry cough and worsening shortness of breath after a recent hospital admission for MRSA bacteremia.Patient was admitted 1 week before presentation for symptoms of pyelonephritis and was found to have MRSA bacteremia for which he was discharged on IV daptomycin for 6 weeks. On admission,patient was febrile with hypoxic to 81%. Labs did show leukocytosis with mild peripheral eosinophilia.PCR for respiratory viruses including covid was negative.Chest X ray was done, which was consistent with multifocal Pneumonia which was followed by Chest CT scan which demonstrated new bilateral dense ground-glass and consolidative opacities.Given concerns for aspiration pneumonia, fungal infections or eosinophilic pneumonitis,pulmonology was consulted for possible bronchoscopy.Bronchoscopy with BAL was done the next day.BAL revealed a WBC of 260/μL with 45% eosinophilic predominance. Given the bronchoscopy results,his symptoms were attributed to Daptomycin related eosinophilic pneumonia.Patient was started on 40mg oral prednisone for a total of 4 weeks with rapid taper.Over the hospital course, his symptoms completely resolved. Discussion: The prosed mechanism involves presentation of drug or drug-hapten combination by the macrophages to the T helper cell results in interleukin-5 release which along with macrophage released eotaxin, results in eosinophilic migration to lungs.The criteria for to diagnose AEP due to daptomycin consist of 4 components which includes febrile illness,hypoxemia,diffuse bilateral pulmonary infiltrates and BAL with >25% eosinophils.Peripheral eosinophilia may not be present in all cases. It is also possible that daptomycin, a renally excreted drug, persists in the lungs of patients with renal dysfunction as seen in our patient and as such may lead to higher incidence of daptomycin induced AEP.In most cases, a short course of steroids(2-3 weeks)is sufficient for complete resolution of symptoms. Conclusion: Daptomycin induced AEP is increasingly seen in patients with high doses of drug and underlying renal dysfunction,and not related to therapy duration as it can occur as early as day 3 of treatment and as late as week 6 of treatment course. Bronchoscopy with BAL should be considered in all cases suspected. (Figure Presented).