Distribution of the PFGE types observed in Survey 1 (SEERAD, black bars) and Survey 2 (IPRAVE, green bars). Distribution of PFGE types is organized so that the first 12 represent PFGE types that are common to both the field surveys. Asterisks represent PFGE types known to be present in human clinical samples for the same time frame. Inset graph is the diversity profiles for the Survey 2 (IPRAVE, green) and Survey 1 (SEERAD, black) surveys illustrating the significantly higher diversity of PFGE types observed in Survey 2 (IPRAVE). Dotted lines represent the confidence intervals for Survey 2 (IPRAVE) data generated by subsampling to the size of Survey 1 (SEERAD).