TABLE 3.

Resolution of discrepant FluoroType MTBDR rifampin and isoniazid resistance results using Sanger sequencing and Genotype MTBDRplus results obtained from DNA extracted from sputum specimens^a

Antimicrobial	Smear result	Initial classification	MTBDRplus resultb	FluoroType MTBDR resultc	Method used to resolve discrepancyd	Final result	Reclassification
Rifampin	Positive	False resistant (n = 3)	WT	D516V	MTBDRplus	WT + D516V	True resistant
			WT	MUT	Sequencing	Q513P	True resistant
			WT	ins(514-515)	Sequencing	TTC ins(514-515)	True resistant
		False sensitive (n = 4)	S531L	WT	MTBDRplus	WT	True resistant
			WT + S531L	WT	MTBDRplus	WT	True resistant
			D516V	WT	MTBDRplus	WT	True resistant
			WT + D516V	WT	Sequencing	WT + D516V	False sensitive
	Negative	False resistant (n = 3)	WT	S531L	MTBDRplus	S531L	True resistant
			WT	MUT	Sequencing	WT + D516Y	True resistant
			WT	S531L	MTBDRplus	WT	False resistant
Isoniazid	Positive	False resistant (n = 3)	WT	S315T2	MTBDRplus	WT + S315T1	True resistant
			WT	S315T1	MTBDRplus	WT + S315T1	True resistant
			WT	MUT	MTBDRplus	WT	False resistant
		False sensitive (n = 2)	S315T2	WT	MTBDRplus	WT	True sensitive
			S315T1	WT	MTBDRplus	WT	True sensitive
	Negative	False resistant (n = 2)	WT	S315T1	MTBDRplus	S315T1	True resistant
			WT	C-15T	No valid result obtained		False resistant

^aDefinitions of abbreviations: WT, wild type; MUT, undifferentiated mutation; ins(514-515), insertion between codons 514 and 515.

^bGenoType MTBDRplus result from DNA extracted from cultured isolate.

^cFluoroType MTDR result from DNA extracted from sputum specimen.

^dDiscrepancies were resolved by using either the sequencing or GenoType MTBDRplus results from DNA extracted from sputum specimens.