Post Antibiotic Effect
The Post-Antibiotic Effect (PAE) shows the capacity of an antimicrobial drug to inhibit the growth of bacteria after removal of the drug from the culture.
To determine the PAE a liquid culture with an initial count of 106 to 107 colony forming units (CFU) per ml is exposed to a certain concentration of the drug for a certain time. A control group is left untreated. After the given time, drug of the treated culture is removed e.g. by dilution 1:1000 in fresh, drug-free medium. The untreated control is undertaken the same procedure. The time for both colonies to increase their CFU by 1 log10 is measured.
PAE is defined as the time a culture that was treated with an antibiotic needs to increase the number (CFU) by 1 log10 compared to untreated controls, and is usually given in hours.
The PAE provides additional time for the immune system to remove bacteria that might have survived antibiotic treatment before they can eventually regrow after removal of the drug from the animal's organism. A longer PAE can therefore influence the clinical outcome of antimicrobial therapy.
Baytril shows a pronounced PAE in bacteria and mycoplasma.
