tailieunhanh - Chapter 127. Treatment and Prophylaxis of Bacterial Infections (Part 10)

Status of the Host Various host factors must be considered in the devising of antibacterial chemotherapy. The host's antibacterial immune function is of importance, particularly as it relates to opsonophagocytic function. Since the major host defense against acute, overwhelming bacterial infection is the polymorphonuclear leukocyte, patients with neutropenia must be treated aggressively and empirically with bactericidal drugs for suspected infection (Chap. 82). Likewise, patients who have deficient humoral immunity (., those with chronic lymphocytic leukemia and multiple myeloma) and individuals with surgical or functional asplenia (., those with sickle cell disease) should be treated empirically for infections with encapsulated organisms,. | Chapter 127. Treatment and Prophylaxis of Bacterial Infections Part 10 Status of the Host Various host factors must be considered in the devising of antibacterial chemotherapy. The host s antibacterial immune function is of importance particularly as it relates to opsonophagocytic function. Since the major host defense against acute overwhelming bacterial infection is the polymorphonuclear leukocyte patients with neutropenia must be treated aggressively and empirically with bactericidal drugs for suspected infection Chap. 82 . Likewise patients who have deficient humoral immunity . those with chronic lymphocytic leukemia and multiple myeloma and individuals with surgical or functional asplenia . those with sickle cell disease should be treated empirically for infections with encapsulated organisms especially the pneumococcus. Pregnancy increases the risk of toxicity of certain antibacterial drugs for the mother . hepatic toxicity of tetracycline affects drug disposition and pharmacokinetics and because of the risk of fetal toxicity severely limits the choice of agents for treating infections. Certain antibacterial agents are contraindicated in pregnancy either because their safety has not been established categories B and C or because they are known to be toxic categories D and X . Table 127-5 summarizes drug safety in pregnancy. Empirical Therapy In many situations antibacterial therapy is begun before a specific bacterial pathogen has been identified. The choice of agent is guided by the results of studies identifying the usual pathogens at that site or in that clinical setting by pharmacodynamic considerations and by the resistance profile of the expected pathogens in a particular hospital or geographic area. Situations in which empirical therapy is appropriate include the following Life-threatening infection. Any suspected bacterial infection in a patient with a life-threatening illness should be treated presumptively. Therapy is usually begun with .