Minor drug-resistant HIV type-1 variants in breast milk and plasma of HIV type-1-infected Ugandan women after nevirapine single-dose prophylaxisDaniel Pilger, Andrea Hauser, Claudia Kuecherer, Kizito Mugenyi, Rose Kabasinguzi, Sybille Somogyi, Gundel Harms, Andrea Kunz
Corresponding author name: GundelHarms
Corresponding author e-mail: firstname.lastname@example.org
Citation: Antiviral Therapy 2011; 16:109-113
Date published online: 29 November 2010
Background: Nevirapine single-dose (NVP-SD) reduces mother-to-child transmission of HIV type-1 (HIV-1), but frequently induces resistance mutations in the HIV-1 genome. Little is known about drug-resistant HIV-1 variants in the breast milk of women who have taken NVP-SD.
Methods: Blood and breast milk samples of 39 HIV-1-infected Ugandan women were taken 6–12 weeks after NVP-SD intake. Samples were analysed by population sequencing and allele-specific real-time PCR (AS-PCR) with detection limits for NVP-resistant HIV-1 variants (K103N and Y181C) of <1% of the total viral population.
Results: AS-PCR results for both plasma and breast milk were obtained for 19 women who constituted the final study group (HIV-1 subtype frequencies were A1 n=11, D n=5, G n=2 and C n=1). A total of 7 (37%) and 10 (53%) women carried NVP-resistant virus in breast milk and plasma, respectively. Overall, 71% (5/7) women with NVP-resistant HIV-1 in breast milk displayed >1 drug-resistant variant. Resistance in breast milk was higher at week 6 (6/13 samples [46%]) compared with week 12 (1/6 samples [17%]). In total, 10 drug-resistant populations harbouring the K103N and/or Y181C mutation were detected in the 19 breast milk samples; 7 (70%) were caused by resistant minorities (<5% of the total HIV-1 population). In the four women with drug-resistant virus in both plasma and breast milk, the mutation patterns differed between the two compartments.
Conclusions: Minor populations of drug-resistant HIV-1 were frequently found in breast milk of Ugandan women after exposure to NVP-SD. Further studies need to explore the role of minor drug-resistant variants in the postnatal transmission of (resistant) HIV-1.