Table 2. Analysis of positive predictive value (PPV) for each serovar grown on different selective media^a.

E. coli serovars	SMAC	CHROMagar	R&F	Rainbow	BHI
O103	0.91	NG	0.81	0.92	0.96
O111	0.93	0.88	0.97	0.93	0.98
O121	0.97	0.94	0.91	0.93	0.94
O145	0.91	0.86	0.93	0.89	0.93
O157	1	0.95	0.84	0.98	0.94
O26	0.95	0.92	0.91	0.94	0.89
O45	0.91	0.87	0.9	0.97	0.92

^aObtained by calculating the cross-validation matrix and reporting the positive predictive value [55], [56]. Rainbow and SMAC agar showed the best average PPV for seven serovars tested; in particular SMAC showed 100% of classification for O157.