Host factors in bacteremia.

Host factors in bacteremia can be divided into nonspecific and specific immune responses. The main components of the nonspecific immune response of the host are phagocytes and complement, and those of the specific response are immunoglobulin and cell-mediated immunity. All of these factors work in concert to protect against bacteria in the bloodstream. Immunoprophylaxis and immunotherapy have come about as a result of growing awareness of the importance of natural host defenses in combating serious bacterial infections. Although the prognosis for patients with bacteremia has improved substantially with recent advances in antibiotic therapy and supportive care, morbidity and mortality rates remain significant. Modulation of the immune system appears to be a promising means of improving the survival rate of patients with bacteremia.