Antibiotics Producing Soil Microorganisms

Abstract

Antibiotics are antibacterial biological substances produced by other microorganisms (actinomycetes/fungi) whereas chemotherapeutic agent is synthetically produced. Antibiotics such as chloramphenicol and erythromycin are derived from other bacteria or fungi. Some of the antibiotics are chemically modified to improve the therapeutic range or pharmacodynamic properties. Originally purified from the cultures of bacteria or fungi, antibiotics are now synthetically manufactured. The term antimicrobial agent is now preferred to include both modified biological products and chemically synthesized biological products. Antimicrobial drugs are either bactericidal or bacteriostatic; the former kills the bacteria whereas the latter only inhibits its multiplication. Bactericidal drugs are preferred over bacteriostatic drugs as the cessation of therapy with the latter may lead to renewed multiplication and relapse of infection. Bacteriostatic drugs often rely on individual's immune response to eradicate bacteria. These drugs should not be used where effective immune response does not occur (endocardium or meninges). Examples of bactericidal drugs include penicillin, ceftriaxone, and gentamicin. Examples of bacteriostatic drugs include chloramphenicol and tetracycline. Some antimicrobial agents have narrow range of activity or active on specific bacterium, others have broad-spectrum range of activity. Examples of the former include erythromycin, azithromycin, clindamycin, and vancomycin whereas; the examples of the latter include cefotaxime, ciprofloxacin, and amikacin.