Antibiotics and Antitoxins

Alexander Fleming in 1928 made a serendipitous discovery that Staphylococcus bacteria would not grow in the presence of the fungus Penicillium notatum. Eventually, the active ingredient, penicillin, was isolated and since 1941 it has been of great value in the control of certain bacterial diseases, especially syphilis, pneumococcal pneumonia, and some staphylococcal and streptococcal infections. Shortly thereafter, in 1943, Selman Waksman and Albert Shatz found streptomycin, produced by the actinomycete Streptomyces gri-seus, which was effective against tuberculosis and many gram-negative bacteria. In addition to many other antibacterials, compounds active against some fungi and protozoa have since been developed, and most recently there has been success with antiviral compounds. The term antibiotic dates from 1889, when Paul Vuillemin used it for a chemical compound produced by Pseudomonas aeruginosa that was inhibitory to other bacteria.

An antibiotic is a chemical that can be used to control the activity of selected microorganisms, especially within the body (as opposed to a disinfectant, which is used outside the body and which is not selective). Specific antibiotics are typically effective against a particular range of pathogens. A wide array of antibiotics now exist, with many produced by other organisms but some produced synthetically. Antibiotics have become a major tool in the control of disease. However, strains of pathogens that are resistant to our present antibiotics have emerged, and the search for new ones thus continues with a sense of urgency.

In some cases it is a toxin produced by the microbial agent that is a major cause of disease. Chemicals that are able to prevent or counteract these toxic effects are referred to as antitoxins. A few such compounds have been developed, including those effective against botulism and diphtheria toxin (Table 12.9).

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