TABLE 1.

Accuracy of genotypic prediction rules V.1 when applied to the Boston validation set^a

Antimicrobial	V.1 rules applied to the Boston validation set
	Total no. of isolates	Phenotypic susceptibility rate, %	Genotype used for resistance prediction (V.1)	Categorical agreement, %	Very major error rate (FN), % (95% CI)	Major error rate (FP), % (95% CI)	PPV, %	NPV, %
Ampicillin	203	12	Mutation of pbp5 485M	99	1.1 (0.13, 4.0)b	0 (0, 13)	100	92.6
Vancomycin	204	21	Presence of vanA or vanB	99	0 (0, 2.3)	2.3 (0.06, 12)c	99.4	100
Gentamicin, high level	198	94	Presence of aac(6′)-le-aph(2”)-la	100	0 (0, 28)	0 (0, 1.9)	100	100
Ciprofloxacind	198	15	Mutation of gyrA (84S) or parC (82S)	100	0 (0, 2.2)	0 (0, 11)	100	100
Levofloxacind	205	15	Mutation of gyrA (84S) or parC (82S)	100	0 (0, 2.1)	0 (0, 11)	100	100
Tetracycline	205	24	Presence of tet(L), tet(M), or tet(S)	97	0 (0, 2.4)	14 (5.8, 27)	95.7	100
Doxycycline	205	29	Presence of tet(M)	91	1.4 (0.16, 4.9)	27 (16, 40)	90.0	95.7
Linezolidd	200	99	Mutation of 23S rRNA G2576T in at least 3 alleles	100	0 (0, 84)	0 (0, 1.8)	100	100

^aFN, false negative; FP, false positive; PPV, positive predictive value; NPV, negative predictive value.

^bBoth isolates that were phenotypically resistant to ampicillin harbored wild-type pbp5 Met485 but had an aspartic acid inserted after position 466 (Asp466′).

^cA single vancomycin-variable enterococcus, which appeared phenotypically susceptible but could gain vancomycin resistance during treatment, was conservatively classified as a major error.

^dAntibiotic for which intermediate isolates were considered with susceptible isolates.