Table 1Influence of nucleoside reverse transcriptase inhibitor resistance-associated mutations (IAS-USA 2005 list) on viral fitness measures

NRTI-resistance mutationsFitness compared with wild-typeFitness compared with other mutantsType of evidence and techniquePresence of drugsReference
K70R97%>> T215Y, M41L, L210WIn vitro, growth competitionNo[4850]
K70RM41L, T215Y>In vivoZDV[51]
D67N>WTIn vitro, growth competitionZDV[52]
K219Q or E>WTIn vitro, growth competitionZDV[52]
T215Y85%>M41L, L210WIn vitro, growth competitionNo[4850]
M41L80%>L210WIn vitro, growth competitionNo[4850]
T215D or S100%>T215Y T215D >T215SIn vitro, growth competitionNo[53,54]
T215C or D>T215Y T215C >T215SIn vivoNo[55]
L210W21%M41L > L210WIn vitro, growth competitionZDV[48]
M184IWT>>M184V>>In vitro, growth competitionNo[56]
M184VWT>>; 57%>> M184IIn vitro, growth competition. Ex vivo, single-replication cycle assayNo[56,57]
M184V10%>M184IIn vivo, population dynamicsYes[22]
L74V89–94%K70R, M184V>; K65R>In vitro, growth competitionNo[58,59]
L74V100%= M184VIn vitro, growth competitionddI[59]
K65RFrom 55%–57% to 68%–90%; with M184V 30%>K65R + L74VEx vivo: single-replication cycle assayNo[57,58,60,
Insertions codon 69WT>>In vitro, growth competitionYes, in the context of TAMS[62,63]
Q151M complex> WT in the presence of F77LIn vitro, growth competitionNo[12,64,65]

ddI, didanosine; IAS-USA, International AIDS Society-USA; NRTI, nucleoside reverse transcriptase inhibitor; TAM, thymidine analogue mutation; WT, wild-type; ZDV, zidovudine; >>, much greater than.

From: Chapter 12, The impact of resistance on viral fitness and its clinical implications

Cover of Antiretroviral Resistance in Clinical Practice
Antiretroviral Resistance in Clinical Practice.
Geretti AM, editor.
London: Mediscript; 2006.
Copyright © 2006, Mediscript.

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