Table 1.

Diagnostic performances of SCITB agar plus the spot indole test and MacConkey agar as a screening test for Klebsiella oxytoca in the first 1,650 diarrheal stool samples^a

Test	No. of samples
	Positive for K. oxytoca	Negative for K. oxytoca
SCITB agar plus spot indole test, K. oxytoca	28	0
SCITB agar plus spot indole test, non-K. oxytoca	2	1,620
MacConkey agar, K. oxytoca	19	641
MacConkey agar, non-K. oxytoca	11	979

^aThe diagnostic gold standard for K. oxytoca was defined as suspected colonies on SCITB agar that were positive by the spot indole test or suspected colonies on MacConkey agar, with these suspected colonies from either agar being further confirmed by conventional biochemical methods and the Vitek II automated identification system. The sensitivity and specificity of SCITB agar plus the spot indole test were 93.3% (95% confidence interval [CI], 76.5 to 98.8%) (28/30) and 100% (95% CI, 99.7 to 100%) (1,620/1,620), respectively, and those of MacConkey agar were 63.3% (95% CI, 43.9 to 79.5%) (19/30) and 60.4% (95% CI, 58.0 to 62.8%) (979/1,620), respectively. The screening performance of SCITB agar plus the spot indole test was found to be significantly better than that of MacConkey agar by McNemar's test (P = 0.022). The number of patients requiring standard biochemical identification was 23 times [(19 + 641)/28] higher if MacConkey agar was used as a screening test than if SCITB agar with the spot indole test was used.