173. Successful Treatment of Carbapenem-Resistant Klebsiella pneumoniae (CR-Kp) Aortic Valve Endocarditis with Ceftazidime–Avibactam

BACKGROUND: The emergence of carbapenem-resistant Klebsiella pneumoniae (CR-Kp) presents significant clinical challenges with our limited antibiotic armamentarium. Infective endocarditis caused by CR-Kp is rare, with few cases reported in the literature. The use of the novel β-lactam/β-lactamase inhibitor combination ceftazidime–avibactam (CAZ-AVI) in this setting has only been described in one 2018 case in Italy. Guidance in how these novel antibiotics should be used becomes more prudent as the prevalence of complicated CR-Kp infections increases. METHODS: A 51-year-old male with a past medical history of a gunshot wound to the neck, type 2 diabetes, and osteomyelitis status post right below-the-knee and left toe amputations presented to the emergency department with altered mental status and right upper extremity weakness. The patient’s hospital course was complicated by hemorrhagic stroke, left above-the-knee amputation, and intraoperative cardiac arrest. Subsequently, blood cultures on hospital days 41 and 43 grew CR-Kp and a transthoracic echocardiogram (TTE) showed moderate to severe aortic regurgitation. RESULTS: Antimicrobial therapy was changed from imipenem-cilastatin and colistin to CAZ-AVI and amikacin. The organism was found to be susceptible to CAZ-AVI and amikacin, intermediate to colistin, and resistant to all carbapenems. A transesophageal echocardiogram (TEE) confirmed the presence of a small mobile vegetation on the aortic valve with perforation and severe regurgitation. CAZ-AVI and amikacin were continued for two weeks, and then switched to CAZ-AVI and ertapenem for an additional four weeks. Follow-up blood cultures on and after day 44 were negative for CR-Kp. A TTE performed after therapy completion no longer demonstrated aortic regurgitation; however, the valves were poorly visualized. The patient then suffered anoxic brain injury after a second cardiac arrest, thought to be unrelated to endocarditis. The patient’s family then decided on hospice care and the patient expired. CONCLUSION: We report the successful treatment of CR-Kp endocarditis with CAZ-AVI and amikacin for two weeks followed by CAZ-AVI and ertapenem for four weeks. This regimen can be a viable option for patients that present with this rare multidrug-resistant infection. DISCLOSURES: All authors: No reported disclosures.