PREVENTION

Chemoprophylaxis is the use of an antimicrobial agent to prevent infection. Chemoprophylaxis is often administered after exposure to a virulent pathogen or before a procedure associated with risk of infection. Chronic chemoprophylaxis is sometimes administered to persons with underlying conditions that predispose to recurrent or severe infection. Antibiotics can also be used to prevent clinical disease in persons infected with a microorganism such as Mycobacterium tuberculosis. This strategy has been called secondary prophylaxis but is now referred to as pre-emptive therapy. Immunization, another excellent means of preventing infection, is discussed in Chapter 113, Immunizations. This chapter discusses the specific areas where antimicrobial prophylaxis is generally accepted. For information on prophylaxis of bacterial endocarditis, see Chapter 36, Endocarditis of Natural and Prosthetic Valves: Treatment and Prophylaxis; for information on prophylaxis in persons infected with the human immunodeficiency virus (HIV), see Chapter 100, Prophylaxis of Opportunistic Infections in HIV Disease; for malaria prophylaxis, see Chapter 198, Malaria: Treatment and Prophylaxis; for prophylaxis related to transplant recipients and neutropenic patients, see Chapter 87, Infections in Transplant Patients, and Chapter 84, Infections in the Neutropenic Patient; and for surgical prophylaxis, see Chapter 112, Surgical Prophylaxis.

Several concepts are important in determining whether chemoprophylaxis is appropriate for a particular situation. In general, prophylaxis is recommended when the risk of infection is high or the consequences significant.