The present work examines the diversity and dynamics of antibioticresistant
bacterial communities of a traditional cheese during themanufacture
and ripening, using the PCR-DGGE technique.
Tetracycline and erythromycin were selected as the target antibiotics since resistance to themis widely spread among lactic acid bacteria species (Ammor et al.,
2007), thus having the highest risk of horizontal transfer.
Cabrales, a Spanish traditional, blue-veined cheese made from raw milk without
the use of starter and ripening cultures (Flórez and Mayo, 2006) was
selected as the cheese model.
The PCR-DGGE technique was used after harvesting cultivable bacteria grown on a non-selective medium and on selective/differential media (for counting bacteria of different groups).
To our knowledge, this is the first study in which indirect PCR-DGGE has been used to characterise the bacterial populationsinvolved in antibiotic resistance in cheese along manufacturing and ripening stages. The technique was found valuable for identifying,
quantifying and tracking tetracycline- and erythromycin-resistant communities.