Campbell MS, Gottlieb GS, Hawes SE et al. PLoS One 2009;4:e5690.
Campbell and colleagues used molecular and computational analysis to evaluate the relatedness of HIV-1 strains among a cohort of eight seroconcordant HIV-1-infected couples in the category of men who have sex with men.
Acquisition of two or more unique HIV-1 strains may occur during primary infection (“dual” infection) or after primary infection, known as superinfection. Infection with multiple strains is well documented in all HIV risk groups, and is associated with the transmission of drug-resistant strains and accelerated HIV disease progression. In the present study, Campbell and colleagues isolated HIV clinical isolates, and used nested polymerase chain reaction (PCR) to sequence the C2-V5 fragment of the envelope (Env) gene, followed by phylogenetic analysis using the HIV sequence database, and computational methods to evaluate for recombination. One pair among eight couples (men who have sex with men) studied showed evidence of superinfection, suggesting that this may occur more frequently than previously suspected.