Innate bacteriostatic and bactericidal activity of normally sterile human body fluids

Forty-four cerebrospinal fluids and 14 pleural fluids were tested for innate bacteriostatic and bactericidal activity against six pathogens. Innate activity was demonstrated in only two cerebrospinal and two pleural fluids. Serum static and cidal activity was demonstrated in four specimens from patients with negative fluid activity. The conclusion is that innate static and cidal activity in serum is not usually present in cerebrospinal and pleural fluid.