Total bacterial genomic DNA, used as a template, was extracted
from cultivable bacteria grown without and with tetracycline or erythromycin (both at 25 μg ml−1
) on a nonselective
medium used for enumeration of total and viable cells (Plate Count agar with Milk; PCA-M), and
from those grown on selective and/or differential agar media used for counting various bacterial groups;
i.e., lactic acid bacteria (de Man, Rogosa and Sharpe agar; MRSA), micrococci and staphylococci (Baird–Parker
agar; BPA), and enterobacteria (Violet Red Bile Glucose agar; VRBGA)