16S rRNA Gene Sequencing The 16S rRNA gene was sequenced for a random subset of 323 of the 459 isolates as described previously (Davelos et al., 2004c) (plot 1, n=146; plot 2N, n=51, plot 3, n=39; plot 4N, n= 27; plot 5, n= 42; plot 6N, n=18).