TABLE 2.

Verigene BC-GN analytic results by bug-drug combination^a

Institution and target organism	n	Target drug	Resistance marker	No. (%) of resistant isolates	No. of isolates identified by Verigene	SN (%)	SP (%)	PPV (%)	NPV (%)
Detroit Medical Center
E. coli	384	Ceftriaxone	Any (CTX-M)b	63 (16)	56	89	99	97	98
K. pneumoniae	140	Ceftriaxone	Any	39 (28)	33	85	99	97	94
	140	Ertapenem	KPC	7 (5)	6	86	100	100	99
K. oxytoca	23	Ceftriaxone	Any (CTX-M)b	2 (9)	1	50	100	100	95
Proteus spp.	57	Ceftriaxone	Any (CTX-M)b	7 (12)	4	57	100	100	94
Enterobacter spp.	61	Cefepime	Any (CTX-M)b	3 (5)	1	33	100	100	97
Citrobacter spp.	10	Cefepime	Any	0	0				100
Acinetobacter spp.	39	Meropenem	OXA	10 (26)	8	80	93	80	93
Pseudomonas spp.	51	Cefepime	Any	6 (12)	0				88
University of Maryland Medical Center
E. coli	105	Ceftriaxone	Any (CTX-M)b	15 (14)	14	93	100	100	99
K. pneumoniae	57	Ceftriaxone	Any	15 (26)	12	80	100	100	93
	57	Ertapenem	KPC	5 (9)	5	100	100	100	100
K. oxytoca	9	Ceftriaxone	Any	0	0				100
Proteus spp.	11	Ceftriaxone	Any	0	0				100
Enterobacter spp.	34	Cefepime	Any (CTX-M)b	3 (9)	3	100	100	100	100
Citrobacter spp.	6	Cefepime	Any	0	0				100
Acinetobacter spp.	14	Meropenem	OXA	5 (36)	5	100	100	100	100
Pseudomonas spp.	43	Piperacillin-tazobactam	Any	15 (35)	0				65

^aNPV, negative predictive value; PPV, positive predictive value; SN, sensitivity; SP, specificity. The cells for SN, SP, and PPV were left blank if either no resistance to the target drug was seen in study isolates or Verigene did not identify any resistance for the target drug.

^bWhile the presence of any resistance marker was tested as a marker of ceftriaxone resistance in E. coli, K.oxytoca, and Proteus spp. or cefepime resistance in Enterobacter spp., only CTX-M was identified in this study for each of these species.