Serological investigation of enterococcal infections using Western blot

To assess the usefulness of Western blot in the diagnosis of enterococcal infections, a pilot study was conducted with a newly developed Western blot using sera from patients with confirmed enterococcal infections. Sera from 17 of 19 patients with enterococcal endocarditis reacted strongly to enterococcal antigens on the Western blot, and most produced specific bands at molecular weights 98 kDa and 54 kDa. Sera from patients with bacteremic cholangitis and pyelonephritis reacted frequently as well, but the pattern of bands was different from that observed with endocarditis. Eighty-five percent of 26 sera tested from patients with bacteremia and associated deep-seated infections (endocarditis, cholangitis, and pyelonephritis) were positive on Western blot, compared to 30% of sera from bacteremic patients with no clinically determined deep focus of infection (p<0.001).