Table 2.

Summary of the performance characteristics and costs of commercially available molecular detection and typing methods for C. difficile compared to those of MMLVA

Assay	Manufacturer	Function	Test method	Batch size	Instrumentation for:		Interpretation	Concern(s)	Advantage(s)	Avg time	Costa
					DNA extraction	Detection
BD GeneOhm C. difficile	Becton Dickinson	Detects C. difficile toxin B gene	PCR	8	Heat lysis	SmartCycler	Cepheid SmartCycler software	Cost, throughput	Good specificity	2-3 h	$25-$30
ProGastro CD	GenProbe	Detects C. difficile toxin B gene	PCR	8	Automated extraction MagNa Pure	SmartCycler	Cepheid SmartCycler software	Cost, throughput	Good specificity	2-3 h	$25-$30
Illumigene C. difficile	Meridian Bioscience	Detects PaLoc gene segment; codes for both toxin A and B genes	Loop-mediated amplification technology (LAMP)	10	Illumigene sample prepn apparatus, heat lysis	Illumipro-10	Illumipro-10 ratio of initial to final signal (turbidity)	Newer methodology	Minimal equipment required; rapid	40 min	$25-$30
Xpert C. difficile	Cepheid	Detects C. difficile toxin B gene	PCR	10 cartridges, 120 cartridges	GeneXpert System	GeneXpert System	Cepheid SmartCycler software	Cost, throughput	Good specificity	2 h	$35-$40
MMLVA	This study—in-house test	Detects C. difficile, toxin A, toxin B, binary toxin, tcdC gene plus VNTRsb	PCR sequencing and fragment analysis	1 to 48	QIAcube (Qiagen)/InstaGene Matrix	3130xl genetic analyzer (Life Technologies)	GeneMapper software	High setup cost, technical expertise	Highly discriminatory detection and typing	5 h	$5-$10
GenoType CDiff	Hain Lifescience	Detects C. difficile, toxin A, toxin B, binary toxin, tcdC gene, resistance to moxifloxacin	DNA strip technology	12	GenoType CDiff	GenoType CDiff	Visual assessment	Typing lacks discriminatory power	Detection and typing performed simultaneously	5 h (stool direct)	$30-$35

^aCosts are in Canadian dollars and meant only to be approximate for reagnets alone.

^bVNTRs, variable-number tandem repeats.