Objective: To determine the presence of NVP resistance mutations in treatment na•ve Ugandan women following a single 200 mg dose of NVP given at onset of labor for prevention of HIV perinatal transmission.

Methods: HIV RT sequences were analyzed from plasma collected 6 weeks after NVP dosing in labor from 14 women using the PE/Biosystems HIV Genotyping System.

Results: The K103 primary NVP resistance mutation was detected in 6 week samples from 1/3 transmitters and 2/11 non-transmitters. Two of the 3 women had a K/N mixture at 103, suggesting recent selection of the resistant variant. Pre-dose samples were available from 2 of these women; both pre-dose samples lacked the K103N mutation. Other NVP resistance mutations (A98G, L100I, V106A, V108I, Y181C, Y188C, G190A) were absent in all 14 women.

Conclusions: HIV with the K103N mutation can be selected in Ugandan women following a single dose of NVP. This suggests that resistance to non-nucleoside RT inhibitors may be induced in the setting of NVP prophylaxis. Selection of the K103N mutation was unexpected in the absence of prior or concurrent AZT therapy, and suggests that mutations arising during antiretroviral therapy may be different for subtype B vs. non-B HIV.