Tags: bacterial septicemia

Infectious disorders

Infectious diseases comprise those illnesses that are caused by microorganisms or their products. Clinical manifestations of infection occur only when sufficient tissue injury has been inflicted directly by microbial products (e.g., endotoxins and exotoxins), or indirectly by host responses (e.g., cytokines and hydrolytic enzymes released by polymorphonuclear leukocytes). Despite the extraordinary recent advances that have occurred in therapeutics for infectious diseases, a number of basic principles should be followed to prescribe antimicrobials and vaccines is an optimal manner. This chapter addresses the broader issues of treating infectious diseases and provides a number of practical clinical examples to demonstrate rational therapeutics. A rational therapeutic strategy in the management of proved or suspected …

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Epidemiologic and virulence factors in infectious diseases

Epidemiologic considerations Before appropriate therapy can be given for an infectious disease, consideration of epidemiologic factors is essential. This section does not fully discuss the epidemiology (the determinants, occurrence, distribution, and control of health and disease) of infectious diseases. However, a number of basic principles and historical points are worth emphasizing. Basic principles of transmission. An infectious disease results from the interaction between an infectious agent and a susceptible host. The agent may originate from a source external to the host (exogenous infection), or, because of changes in the agent–host relationship, a normally occurring, usually innocuous, microbial agent on skin or mucosal surfaces can produce disease (endogenous infection). The relationship among …

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Documentation of infection

Review of the patient’s history and symptoms combined with knowledge of the microorganisms that cause infection at specific sites (e.g., E. coli is the most common cause of urinary tract infection in young women, whereas S. pneumoniae is the most common cause of pneumonia at all ages) allows one to order the appropriate investigations to document the site of infection and the infecting microorganism. Nonspecific Methods Symptoms and physical signs are frequently supportive of a diagnosis of infection but rarely are pathognomonic. For example, the activation of the acute inflammatory response is the most common way in which the clinical manifestations of infection become apparent. However, noninfectious conditions may also activate …

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Toxicity of Antimicrobial Therapy

Mechanisms of toxicity The mechanisms associated with common adverse reactions to antimicrobials include dose-related toxicity that occurs in a certain fraction of patients when a critical plasma concentration or total dose is exceeded, and toxicity that is unpredictable and mediated through allergic or idiosyncratic mechanisms. For example, certain classes of drugs such as the aminoglycosides are associated with dose-related toxicity. In contrast, the major toxicity of the penicillins and cephalosporins is due to allergic reactions. These differences are explained in part by the relative ability of specific drugs to inhibit enzymatic pathways in the host versus their stimulation of specific immune response. Not included in these lists is mention of the …

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Aminoglycosides – antibiotic agents

Aminoglycosides are very potent bactericidal antibiotic agents that are active against susceptible aerobic microorganisms. They kill by inhibiting protein synthesis and to some extent by lysing the cell envelope. All the aminoglycosides (streptomycin, kanamycin, neomycin, gentamicin, amikacin, tobramycin, sisomicin, and netilmicin) share common structural features. Streptomycin is used once a day in combination with other antibiotics to treat mycobacterial infections. Neomycin is used topically to treat superficial infections (a use to be discouraged) and is also given orally preoperatively for chemoprophylaxis before large-bowel surgery. The other agents are used parenterally to treat systemic bacterial septicemia (e.g., bacterial endocarditis, or urinary tract infections) or topically to treat local infection (e.g., bacterial conjunctivitis). …

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