The following animation depicts the mechanism of action of aminoglycosides. This antibiotic class includes drugs such as gentamicin, streptomycin (used for TB treatment), amikacin, among others.


Aminoglycosides mechanism

Susceptible gram-negative organisms allow aminoglycosides to diffuse through porin channels in their outer membranes. These organisms also have an oxygen-dependent system that transports the drug across the cytoplasmic membrane. The antibiotic then binds to the 30S ribosomal subunit prior to ribosome formation .

There, it interferes with assembly of the functional ribosomal apparatus and/or can cause the 30S subunit of the completed ribosome to misread the genetic code. Polysomes become depleted, because the aminoglycosides interrupt the process of polysome disaggregation and assembly. [Note: The aminoglycosides synergize with β-lactam antibiotics because of the latter’s action on cell wall synthesis, which enhances diffusion of the aminoglycosides into the bacterium.]”

From Harvey, R; Champe, P (series editors). “Lippincott illustrated reviews: Pharmacology”, 4th edition. LWW: 2009.:

Aminoglycosides classification

-mycin (Streptomyces)

-micin (Micromonospora)

Further reading

Gilbert, D; Moellering R (editors) “Sanford Guide to Antimicrobial Therapy”, 39th edition. Antimicrobial therapy: 2009

 

Hauser, A. “Antibiotic Basics for Clinicians: Choosing the Right Antibacterial Agent”.1st edition. LWW:2007

 

Gallagher, J. “Antibiotics Simplified”. 1st edition. Jones & Bartlett Publishers: 2008

Animation author

Gary Kaiser
Biology Department
The Community College of Baltimore County, Catonsville Campus
Baltimore, MD 21228
USA
Email: gkaiser@ccbcmd.edu

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