Abstract: A method of identifying species in a sample is based on pairs of consensus amino acid segments which flank variable amino acid segments of type II DNA topoisomerases. In one embodiment, a DNA primer composition termed "universal primers", is used to amplify the DNA segments coding for the variable or "signature" amino acid sequences. The amplified segments are then cloned and sequenced, and the DNA sequence is matched against a database of signature sequences from multiple species. The signature DNA sequences may be convened to the amino acid "signature" sequences for which they code, and these signature sequences matched against a database of amino acid reference sequences, thereby determining which species were present in the original sample. The universal DNA primers are useful to detect and identify multiple unknown microbial species in a sample.