Dr. Saba AbdiAssistant Professor

Department Of BiochemistryKing Saud University

Greek. anti, "against"; bios, "life") An antibiotic is a chemical substance produced by one organism that is destructive to another. The word antibiotic (given by Waksman) came from the word antibiosis a term coined in 1889 by Louis Pasteur's pupil Paul Vuillemin which means a process by which life could be used to destroy life.

Current Definition: Antibiotics are products(metabolites) of various organisms (bacteria, fungi, algae, higher plants,lower and higher animals) which at low concentrations cause inhibition of life processes of any living object.

3000 years ago ancient Egyptians, Chinese and people of central America used molds to cure diseases.

19th century:– Louis Pasteur & Robert Koch: Bacteria as causative agents & recognised need to control them

Alexander Fleming observed the killing of staphylococci by a fungus (Penicillium notatum) observed by others - never exploited

Florey & Chain purified it by freeze drying(1940) - Nobel prize 1945 first use in a patient: 1942 World War II: saved 12-15% of lives

Selman Waksman - Streptomycin (1943) from soil bacteria

– active against all Gram-negatives – first antibiotic active against Mycobacterium tuberculosis Is the first of the new class of drugs called

aminoglycosides – extracted from Streptomyces – 20 other antibiotics, incl. neomycin,

actinomycin

1955 Tetracyclin was patented by Lloyd Conover, which became the most prescribed broad spectrum antibiotic in the United States.

1957 Nystatin was patented and used to cure many disfiguring and disabling fungal infections.

1981SmithKline Beecham patented Amoxicillin or amoxicillin/clavulanate potassium tablets, and first sold the antibiotic in 1998 under the tradenames of Amoxicillin, Amoxil, and Trimox. Amoxicillin is a semisynthetic antibiotic.

1. Cyanobacteria2. Bacteria3. Actinomycetes4. Fungi5. Higher Organisms

Mostly produce toxins that kill higher organisms.

Malingolide is an antibiotic produced by a cyanobacteria.

Out of the 19 different principal groups into which bacterias can be divided (Bergey’s Classification ) the following groups mostly are source of antibioticsBacterial group number Bacterial type

2 Gliding bacteria

7 Gram –ve aerobic rods & cocci

8 Gram –ve facultatively anaerobic rods

14 Gram +ve cocci

15 Bacillus

16 Gram +ve ,asporogenous rods

17 Actinomycetes & related organisms

12 Mycoplasmas

It is the largest source of antibiotics. 90%-95% of which is produced by the genus

“Streptomyces”(soil bacteria). Another genus important for antibiotics

production is Micromonospora

Richest source is the genera “penicillium” and “aspergillus”

Such as algae, lichens, higher plants , protozoa, insects, molluscs, sponges, worms and vertebrates.