On rare occasion a patient with enterococcal (group D streptococcal) endocarditis will exhibit life-threatening penicillin allergy. The selection of vancomycin hydrochloride and streptomycin as alternate therapy to penicillin-streptomycin under such circumstances is supported by a patient here reported who was cured of enterococcal endocarditis after being treated with vancomycin-streptomycin. In addition, studies upon 18 enterococcal isolates confirm previously reported investigations which indicate that vancomycin and streptomycin in combination exert a synergistic action against a substantial percentage of enterococcal isolates in vitro.
Westenfelder GO, Paterson PY, Reisberg BE, Carlson GM. Vancomycin-Streptomycin Synergism in Enterococcal Endocarditis. JAMA. 1973;223(1):37-40. doi:10.1001/jama.1973.03220010023005