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.

Epidemiologic and virulence factors in infectious diseases

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.

Documentation of infection

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 the same inflammatory mechanisms; therefore, the symptoms and signs of inflammation are by no means specific for infection.

Toxicity of Antimicrobial Therapy

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.

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.