Combination of Ceftriaxone and Ampicillin for the Treatment of Enterococcal Endocarditis: A Qualitative Systematic Review

Objective: The aim of this systematic review is to review all human trials assessing the efficacy and safety of ampicillin and ceftriaxone for enterococcal endocarditis and to discuss the clinical implications of the findings. Data Sources: MEDLINE (1946-), EMBASE (1974-), CENTRAL, Google Scholar, and the World Health Organization Clinical Trials Registry Platform were searched through January 2017 using the search terms ampicillin, penicillin, ceftriaxone, cephalosporin, enterococ*, and endocarditis. Unpublished studies were eligible for inclusion. Additional references were identified from literature citations. Study Selection and Data Extraction: Clinical trials in humans that reported on clinical efficacy or adverse outcomes with ceftriaxone and ampicillin therapy in patients with enterococcal endocarditis were included. Case reports, nonhuman, and non-English studies were excluded. Data Synthesis: Four observational clinical studies were identified. One examined the effects of ceftriaxone and ampicillin alone, and 3 compared the therapy to the current standard of care, ampicillin and gentamicin. The studies had small sample sizes and were not adequately designed or powered to establish noninferiority or equivalence to the current standard of care. Rates of clinical cure with ampicillin 2 g every 4 hours and ceftriaxone 2 g every 12 hours were similar to those of ampicillin and gentamicin. Ampicillin and ceftriaxone therapy was well tolerated with low rates of renal failure (0%-33%). Conclusion: The evidence to support the use of ampicillin and ceftriaxone for enterococcal endocarditis is not definitive. In the absence of compelling evidence, clinicians may consider ampicillin and ceftriaxone in patients with Enterococcus faecalis infection at high risk for nephrotoxicity or those with aminoglycoside-resistant pathogens.