TABLE 3.

Characteristics and approximate costs of screening methods to identify fecal carriage of CPE

Method (reference)	Description	Turnaround time for positive or preliminary positive result (h)	Price (US$)a
CDC protocol (138)	Broth enrichment of rectal swab in ertapenem medium followed by subculture on MacConkey agar with carbapenem disk, followed by identification of suspect isolates	48–72e	Negative test result, 1–2b; positive test result, 2–6b
Supercarba (149)	Direct plating of rectal swab in selective medium	24–48e	1c
Chromogenic medium	Direct plating of rectal swab in selective medium with chromogenic molecule	24–48e	4–7
Real-time PCRd (in-house methods)	DNA extraction followed by PCR and probe-based detection	2–5	10–30b
Commercial PCR assayd	DNA extraction followed by PCR and probe-based detection.	2–3 possible	30–60b

^aU.S. dollars as of 2015.

^bBased on cost data by Mathers et al. (136).

^cSupercarba medium has been patented. The cost is that of raw materials; this medium is not available to many laboratories.

^dThe cost of the PCR assay may increase with increased numbers of targets.

^eConfirmation testing might include singleplex PCR, multiplex PCR, Carba NP, Blue-Carba, or identification and susceptibility testing. The cost may range from an additional $2 to $50, and the turnaround time may range from an additional 2 to 24 h for confirmatory testing, depending on the methods chosen by the laboratory. Hospital epidemiology can act on negative results and preliminary positive results, pending confirmation. Negative NAAT results likely do not require confirmatory testing, but positive results may require confirmation, depending on the false-positive rate of the assay.