In the same year as Pasteur, and independently, Sternberg discovered the pneumococcus (Streptococcus pneumoniae) demonstrating its carriage in the healthy human mouth.

Sternberg, U. S. Surgeon General 1893-1902, was a pioneer bacteriologist. Independently of Pasteur he discovered the pneumococcus and was first in America to photograph the tubercle bacillus. He sent Walter Reed off to make his great discoveries regarding yellow fever.

Sternberg demonstrated that the serum of an animal recovered from vaccinia possesses the property of neutralizing the activity of the causative virus. His test was readily adaptable for use in various host-systems.