Use of repetitive DNA sequences and the PCR to differentiate Escherichia coli isolates from human and animal sources

The rep-PCR DNA fingerprint technique, which uses repetitive intergenic DNA sequences, was investigated as a way to differentiate between human and an imal sources of fecal pollution, BOX and REP primers were used to generate DNA fingerprints from Escherichia coli strains isolated from human and anim al sources (geese, ducks, cows, pigs, chickens, and sheep). Our initial stu dies revealed that the DNA fingerprints obtained with the BOX primer were m ore effective for grouping E. coli strains than the DNA fingerprints obtain ed with REP primers. The BOX primer DNA fingerprints of 154 E, coli isolate s were analyzed by using the Jaccard band-matching algorithm, Jackknife ana lysis of the resulting similarity coefficients revealed that 100% of the ch icken and cow isolates and between 78 and 90% of the human, goose, duck, pi g, and sheep isolates were assigned to the correct source groups, A dendrog ram constructed by using Jaccard similarity coefficients almost completely separated the human isolates from the nonhuman isolates, Multivariate analy sis of variance, a form of discriminant analysis, successfully differentiat ed the isolates and placed them in the appropriate source groups. Taken tog ether, our results indicate that rep-PCR performed with the BOS AIR primer may be a useful and effective tool for rapidly determining sources of fecal pollution.