Screening for antimicrobial resistance in normal bacterial flora of the skin using the replica plating method

The replica plating method was evaluated for detection of the antimicrobial resistance of normal bacterial flora of the skin and was compared with the results of a ten-colony method. If greater than or equal to 10% of the col onies from the master plate grew on a plate containing an antibiotic, the s ensitivity of replica plating was comparable to that of a ten-colony method for samples containing resistant bacteria. However, this method classified significantly more samples as resistant to all eight antibiotics tested if the detection breakpoint was lowered to greater than or equal to1% of the original colonies. Replica plating is an effective and practical tool for s creening skin flora for resistance, also in samples with a low proportion o f resistant strains.