As mentioned in an earlier report, the current classes of antibiotics
(See table below) being utilized to fight infection are no longer effective in
regards to certain diseases, especially since many pathogenic organisms have
developed an effective immunity against them.
Classes of Antibiotics
Currently in Use -
Class
|
Mode of Action
|
Example
|
Β-lactam
|
Inhibits bacterial cell wall
biosynthesis
|
Penicillin
|
Aminoglycoside
|
Inhibits protein synthesis in
Gram-negative bacteria such as Streptomyces griseus
|
Neomycin
|
Macrolide
|
Inhibits protein synthesis in
Gram-positive bacteria such as Streptococcus pneumoniae by preferentially
binding to the 50S component of the bacterial ribosome
|
Erythromycin
|
Tetracycline
|
Inhbits protein synthesis by
preferentially binding to the 30S component of the bacterial ribosome
|
Tetracycline
|
Fluoroquinolone
|
Irreversibly binds to and
inactivates key enzymes that maintain bacterial DNA
|
Norfloxacin
|
Note: Antibiotics are
of no use in treating viral infections since the biology of the virus is
markedly different than that of bacterial agents.
There is, however, some basis for renewed optimism in regard
to this global public health concern. Most
antibiotics currently being utilized are natural products produced by cultured
soil micro-organisms. For varied
reasons, some economic in nature, the synthetic production of antibiotics has been
unable to adequately supply new and effective classes of antibiotics. Uncultured bacteria, on the other hand,
although large in number, have been an untapped resource for new antibiotics.
Dr Losee Ling and his
colleagues at the Novobiotic Team,
NovoBiotic Pharmaceuticals, LLC.
767C Concord Ave, Cambridge, MA have developed specific methodologies to
grow uncultured organisms thereby opening up a vast new resource. As a result of an exhausted screening of
uncultured bacteria, they discovered a
new antibiotic that they have called teixobactin (see the structure below).
Teixobactin acts by inhibiting cell wall synthesis. It
accomplishes this by binding to highly conserved constituents of the
bacterial cell wall and, in this way, effectively interfering with cell wall
synthesis resulting in bacterial cell death.
The investigators were able to demonstrate that no resistant strains
were produced when teixobactin was used to undermine the growth of both
Staphylococcus aureus and Mycobacterium tuberculosis- pathogens responsible for
Staphylococcus infections and Tuberculosis, respectively . According to Dr. Ling, “The properties of
this compound suggest a path towards developing antibiotics that are likely to
avoid development of resistance.”
This is a very exciting development in regards to global
public health.
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