Post-antibiotic effect

The post-antibiotic effect (PAE) was first described by Bigger in 1944 and expanded by Parker and Luse in 1948. PAE is the duration of the antibacterial effect of an antibiotic, measured in hours / minutes, after it has fallen below the minimum inhibitory concentration ( MIC / MIC) or to no longer measurable values ​​in the vicinity of the pathogen.

mechanism

The PAE is based primarily on an antibiotic's high binding affinity for certain bacterial structures, in particular proteins . It can best be illustrated with the key / lock principle. The antibiotic is the “key” that fits exactly into a specific molecular structure of the bacterium (“keyhole”). The PAE is based on the fact that the key “sticks” in the binding site. This leads to a long-lasting dysfunction in the bacterial metabolism, which continues even when there is no longer any antibiotic agent in the environment. This mechanism is known from neurophysiology . Many active substances act on their postsynaptic receptor like the physiological transmitter , but have a higher binding affinity. As a result, they block the receptor, which can lead to various malfunctions and even total system failure.

Effects

Possible effects of the PAE on the pathogen are, depending on the type of antibiotic:

• decreased virulence
• retarded growth
• Inhibition of cell wall synthesis
• reduced potential for adhesion to the mucous membrane
• Sensitization of the host, increasing the phagocytosis -rate

Consequences in Therapy

• After a high initial dose to saturate all binding sites on the target pathogen, you can continue with a comparatively low maintenance dose.
• this results in potentially fewer undesirable side effects.
• longer treatment intervals are possible.
• Accidentally forgetting to take a dose is less significant.
• There is a risk of overdosing.

Antibiotics with PAE

In principle, a defined PAE can only be given for the combination of a certain antibiotic with a classified pathogen in a certain host species. Even then, the times determined experimentally can vary considerably. A general PAE with regard to all target pathogens has been proven for only a few whole groups of antibiotics.

Drug groups

• Macrolides such as erythromycin , tylosin and the like. a.
• Tetracyclines such as doxycycline and the like. a.
• Quinolone antibiotics such as ciprofloxacin and the like a.
• Aminoglycosides such as gentamicin , tobramycin and the like. a.

Single active ingredients

• β-lactam antibiotics generally do not have a PAE (exception: carbapenems ).
• Trimethoprim has a PAE of 0.2–2.4 h for Staphylococcus aureus , and no PAE for E. coli .
• Quinapristin / Dalfopristin has a PAE of ~ 10 hours with regard to Staphylococcus aureus in the animal model .
• Linezolid has a PAE of ~ 3.5 h for Staphylococcus aureus

swell

• http://edoc.hu-berlin.de/dissertationen/medizin/hummel-heike/HTML/hummel-ch1.html
• http://www.vetpharm.uzh.ch
• Applied drug therapy & clinical-pharmaceutical care in case studies (Eds.) H. Schneemann; L. Young; MA Koda - Kimbles, p. 627, Springer 2001, ISBN 978-3-54041356-1

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