Resistance mutations in HIV-1 infected pregnant women and their infants receiving antiretrovirals to prevent HIV-1 vertical transmission in China.

The objective of this study was to assess the resistance baseline in HIV-1-infected pregnant women in China and the emergence of drug resistance (DR) among them and their infants after receiving single-dose nevirapine (sdNVP) or zidovudine plus sdNVP (ZDV-sdNVP) for the prevention of mother-to-child transmission (PMTCT). The prospective study followed 62 drug-naïve HIV-1-infected mothers and their infants who received sdNVP for PMTCT and 18 who received ZDV-sdNVP. Primary DR was detected in 8.8% (7/80) of pregnant women at baseline. Two (2.5%) women had mutations associated with nucleoside reverse transcriptase inhibitors (NRTI). Six (7.5%) women harboured mutations associated with non-nucleoside reverse transcriptase inhibitors (NNRTI). No protease inhibitor (PI) DR was detected. The DR rates in infected mothers selected by sdNVP and ZDV-sdNVP regimen were 16.3% and 0%, respectively. Women with the emergence of DR after sdNVP had lower CD4 cell counts at delivery than women without DR after sdNVP (178 vs.364 cells/mm(3), P < 0.05). The vertical transmission rate in women with baseline resistance was similar to that in women without baseline resistance (1/7 vs. 3/73, P > 0.05). The study indicates that NVP resistance after sdNVP was associated with CD4 cell count at delivery. ZDV-sdNVP regimen was of more significance in the prevention of the emergence of NNRTI-related DR than sdNVP.