The minimal bactericidal concentration (MBC) was defined as a 99.9% reduction in CFU from the starting inoculum after 24 h incubation interval.
Conditions for optimal growth were determined by measuring substrate consumption and cell dry weight with two different cell lines, flask volumes, and starting inoculum densities.
The minimal fungicidal concentration (MFC) was defined as a 99.9% reduction in CFU from the starting inoculum after 24 h incubation interval.
To demonstrate the impact of normal (NEK) and impaired elimination kinetics (IEK) of gatifloxacin on its ability to protect from losses in the susceptibility of Staphylococcus aureus, a clinical isolate of methicillin-resistant S. aureus at a starting inoculum of 108 cfu/ml was exposed to 3 days of quinolone dosing.
These ratios were confirmed by retrospective viable counts of the starting inoculum in triplicate.
The starting inoculum size of OD 1.0 at 600 nm was maintained in all the steady state experiments.
After several attempts to optimize biofilm structure formation in S. aureus, we observed that a more dilute starting inoculum aided the generation of tertiary structure within the biofilm.
Conversely, we can examine the total evolution of the viral population from the starting inoculum in cell culture, but cannot in most cases do this in vivo.
Namely, SB produces collapse even if present as a few percentage of the starting inoculum, but the collapse will happen sooner if the initial concentration of SB is higher.
In a similar way, a small percentage of SN can produce stable co-swarming, even though the steady state is reached later than it would happen with a larger percentage of SN on the starting inoculum (See S2 and the description of computational model, further down).
For each test the results show the ratio found in the starting inoculum (DNA extracted at time 0 of the competition), the ratio after competition in the presence and absence of Tween 80 and the ratio of the same strains growing alone.
