Uncertainty of Treatment of Serratia marcescens Endocarditis

Abstract

Aim: To discuss two patient cases of Serratia marcescens endocarditis and the paucity of literature regarding treatment options.
 Presentation of Case: Patient 1 was a 29-year old male who presented with native mitral valve Serratia marcescens endocarditis presumed secondary to intravenous drug use. He was empirically treated with vancomycin and piperacillin/tazobactam then transitioned to meropenem and gentamicin 1 mg/kg every 8 hours. He was maintained on vancomycin monotherapy for days 4-14. Gentamicin was restarted on hospital day 14 at 7 mg/kg every 36 hours for 6 weeks. He underwent mitral valve replacement on hospital day 20. He was readmitted on day 42 with splenic lesions and enlarging mycotic aneurysms. Patient 2 was a 38-year old male with native aortic valve Serratia marcescens endocarditis with septic emboli presumed secondary to intravenous drug use. He was treated with vancomycin and cefepime then was transitioned to ceftriaxone and levofloxacin. The patient underwent aortic valve replacement on hospital day 3 and was transitioned to meropenem and levofloxacin for 6 weeks.
 Discussion: The treatment strategies for both patients demonstrates that the optimal treatment strategy for Serratia marcescens endocarditis remains unclear. The gentamicin dosing for patient 1 demonstrates “synergy” and extended-interval dosing. Despite both dosing strategies being used, the patient continued to exhibit complications of the infection. Patient 2 demonstrates successful treatment of the infection with surgical intervention and a carbapenem/fluoroquinolone regimen.
 Conclusion: These cases demonstrates that much remains unclear in the treatment of Serratia marcescens endocarditis and more studies and case reports are needed.

Serratia marcescens Endocarditis

“…Treatment regimens have included gentamicin, meropenem, levofloxacin, ceftriaxone, and piperacillin-tazobactam [6,17]. Goodberlet et al address this heterogeneity and the high mortality rate, reporting a favorable clinical outcome with meropenem 2 g every eight hours together with levofloxacin 750 mg every 24 h [17]. In the cases of our patients, the antibiotic regimen for Patient 1 is presently unknown, while Patient 2 was treated exclusively with ceftriaxone after sensitivities resulted.…”

“…The therapeutic approach has been largely heterogeneous throughout the literature. Treatment regimens have included gentamicin, meropenem, levofloxacin, ceftriaxone, and piperacillin-tazobactam [6,17]. Goodberlet et al address this heterogeneity and the high mortality rate, reporting a favorable clinical outcome with meropenem 2 g every eight hours together with levofloxacin 750 mg every 24 h [17].…”

“…In the cases of our patients, the antibiotic regimen for Patient 1 is presently unknown, while Patient 2 was treated exclusively with ceftriaxone after sensitivities resulted. To the best of our knowledge, only one other study in the literature utilized ceftriaxone with a favorable result [6,17]. It is possible that clinicians have become wary of the possibility of ceftriaxone to self-select for resistance, but we maintain that more studies need to be performed to determine the most effective antibiotic regimen.…”

Endocardite da Válvula Mitral – Uma Causa Rara num Doente com Neoplasia

“…Historicamente, S. marcescens , um bacilo gram-negativo oportunista, tem sido considerado um agente causador de EI em usuários de drogas intravenosas, mas recentemente foram relatados alguns casos em não usuários de drogas com distúrbios médicos crônicos. 6 - 8 …”

“… 6 , 7 , 9 , 10 A terapia antimicrobiana apropriada é incerta devido à considerável resistência aos antibióticos, mas os regimes aceitos geralmente envolvem uma combinação de um betalactâmico e um aminoglicosídeo. 4 , 5 , 8 A cirurgia é frequentemente negada a pacientes com câncer, mal orientados pelo conceito de carga considerável de comorbidades e a terapia antitumoral geralmente é suspensa. 1 , 2 …”