Download Antibiotics lec.1

Dr. Saba Abdi
Assistant Professor
Department Of Biochemistry
King Saud University
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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
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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
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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
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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.
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Cyanobacteria
Bacteria
Actinomycetes
Fungi
Higher Organisms
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Mostly produce toxins that kill higher
organisms.
Malingolide is an antibiotic produced by a
cyanobacteria.
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Out of the 19 different principal groups into
which bacterias can be divided (Bergey’s
Classification ) the following groups mostly
Bacterial
group number
Bacterial type
are source
of antibiotics
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
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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
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Richest source is the genera “penicillium” and
“aspergillus”
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Such as algae, lichens, higher plants ,
protozoa, insects, molluscs, sponges, worms
and vertebrates.