TABLE 2.

Analysis of the Rep-PCR fingerprint data for E. coli isolates collected during the study using a hierarchical AMOVA

Variance componentObserved partition valueφ statisticP valuea
Variance (σ2)% Total
Pretreatment (days −1 and 0)
    Between treatment groups0.1361.860.019<0.001
    Among individuals within treatment groups1.03014.020.143<0.001
    Within individuals6.18184.130.159<0.001
Posttreatment (days 8, 9, and 10)
    Between treatment groups0.1551.790.0180.004
    Among individuals within treatment groups0.8259.520.097<0.001
    Within individuals7.6988.690.113<0.001
Pretreatment vs posttreatment in treated animals
    Between time periods0.5356.200.062<0.001
    Among individuals within time periods1.07712.480.133<0.001
    Within individuals7.01481.320.187<0.001
  • a P values represent the probability of obtaining a more extreme variance component and φ statistic than the observed values by chance, calculated through 9,999 permutations of the data.