TABLE 3.

Codons at which differences exist between subtype B and non-B viruses

Region	Amino acid position	Wild-type codon in subtype Ba	Amino acid	Subtype(s)	Wild-type codon in non- subtype B	Amino acidb	Mutated codonc	Resistant amino acid	Drugs affectedd
RT	106	GTA	V	C	GTG	V	ATGe	M	EFV, NVP, DLV
	108	GTA	V	G	GTG	V	ATA	I	EFV, NVP
	179	GTT	V	G, A/G	GTG	V	GAG or GAA	E	EFV, NVP, DLV
	179	GTT	V	A	ATT	I	GAT or GAC	D	EFV, DLV
PR	20	AAG	K	A, A/E	AAA	K	ATG	M	IDV, RTV, LPV, ATZ, TPV
	82	GTC	V	G	ATC	I	GCC	A	Multi-PI
	82	GTC	V	G	ATC	I	TCC or AGC	S	Multi-PI
	82	GTC	V	G	ATC	I	ACC	T	Multi-PI

^aThe underlined nucleotides represent transitions or transversions from wild type to nucleotides that code for a resistance-associated amino acid.

^bPresumed polymorphism.

^cNucleotides that encode resistance-associated amino acids.

^dAbbreviations: DLV, delevaridine; IDV, indinavir; RTV, ritonavir; LPV, lopinavir; ATZ, atazanavir; TPV, tipranavir.

^eDifferences in numbers of nucleotide changes needed to mutate a particular drug resistance-associated amino acid. Only frequently observed mutations are shown.