Research Article: Prevalence of Drug Resistance and Associated Mutations in a Population of HIV-1+ Puerto Ricans: 2006–2010

Date Published: April 24, 2012

Publisher: Hindawi Publishing Corporation

Author(s): Lycely del C. Sepúlveda-Torres, Alexandra De La Rosa, Luz Cumba, Nawal Boukli, Eddy Ríos-Olivares, Luis A. Cubano.


This is a continuation of our efforts to maintain a record of the evolution of HIV-1 infection in Puerto Rico by monitoring the expression levels of antiretroviral drug-resistance-associated mutations. Samples from 2,500 patients from 2006–2010 were analyzed using the TruGene HIV-1 genotyping kit and the OpenGene DNA sequencing system. Results show that 58.8% of males and 65.3% of females had HIV-1 with resistance to at least one medication. The average number of HIV mutations was 6.0 in males and 6.1 in females. Statistically significant differences between men and women were recorded in the levels of HIV-1 expressed mutations and antiretroviral drug resistance. The most prevalent antiretroviral medication resistance shifted from zalcitabine to nevirapine and efavirenz in the five-year period. M184V and L63P were the dominant mutations for the reverse transcriptase and the protease genes, respectively, but an increase in the incidence of minority mutations was observed.

Partial Text

Puerto Rico has one of the highest incidences of HIV infections among the United States and it’s jurisdictions. The official data collected by the Puerto Rico Department of Health indicate that the number of persons living with HIV increased from 39,455 to 43,400 from 2006 to 2010 and that 5,027 new diagnoses were performed during the same period of time (1,460 in 2006, 1,016 in 2007, 975 in 2008, 844 in 2009, and 732 in 2010) [1]. A comprehensive analysis of the HIV population in Puerto Rico was performed by the US Centers for Disease Control and Prevention (CDC) using the data for 2006. In that particular year, 71% of the new diagnosed individuals were males. By age group, the greatest number of diagnoses of HIV infection occurred among those aged 30 to 39 years, followed by those aged 40 to 49 years. Among males, the most common mode of HIV transmission was injection-drug use (40%), followed by male-to-male sexual contact (30%). Among females, the most common mode of HIV transmission was high-risk heterosexual contact (73%), followed by injection-drug use (27%). The rate of diagnosis of HIV infection in Puerto Rico in 2006 was 45.0 per 100,000 population, twice the estimated US rate (22.8) and 1.5 times the estimated rate for Hispanics in the United States (29.4). The incidence rate among males in Puerto Rico (62.0) was 1.8 times the rate among US males (34.3) and 1.4 times the rate among US Hispanic males (43.1). The incidence rate among females in Puerto Rico (29.8) was 2.5 times the rate among US females (11.9) and 2.0 times the rate in US Hispanic females (14.4) [2, 3]. However, comparisons between the rates for Puerto Rico and the rates for Hispanics in the United States should consider differences in the two populations since Hispanics in the United States include people of diverse national origins whose behavioral characteristics might differ from Hispanics in Puerto Rico [4]. One major difference between the HIV epidemiology in Puerto Rico and the United States is that injection-drug use continues to be the most common mode of HIV transmission in Puerto Rico, whereas most new HIV infections in the United States are attributed to male-to-male sexual contact [5, 6]. This observation is in agreement with previous reports that highlight a greater prevalence of injection-drug use and high-risk health behaviors related to injection-drug use (e.g., frequency of injecting and sharing syringes and other drug paraphernalia) in Puerto Rico than in the United States [4, 7].

This study is an effort to establish an HIV-1 resistance-monitoring system in Puerto Rico and a continuation of the articles published in 2002, 2008, and 2010 that examined the prevalence of HIV-1 mutations and antiretroviral resistance in the island from 2000 to 2005 [15–17]. As highlighted in our previous reports, statistically significant differences between genders were observed for both antiretroviral resistance levels and mutation incidences. It is of interest to note that some of the gender differences detected in this study were also observed in previous years. In the case of antiretroviral drug resistance, gender differences were recorded for nevirapine in 2004 and 2007. The statistically significant results for the reverse transcriptase mutation K70R have been noted for 2003 and 2006, while gender differences for K103N were observed in 2005 and 2007. Similarly, the protease resistance mutation L90M showed a divergent result between men and women in 2003, 2005, and 2006. Even though it is premature to draw conclusions based on the recurrence of these events, gender difference patterns may emerge once data from subsequent years are made available for analysis.

As observed in previous reports of HIV-1 mutation trends and antiretroviral resistance for Puerto Rican patients, statistically significant differences between genders were observed for both antiretroviral drug resistance levels and mutation incidences in the reverse transcriptase and protease genes. The most abundant antiretroviral drug resistance levels shifted from zalcitabine to nevirapine and efavirenz, and the gap between the most prevalent and the least common antiretroviral drug resistance counts closed significantly. Even though M184V and L63P continue to be the most prevalent mutations for the reverse transcriptase and the protease genes, respectively, a descending trend was observed for most of the mutations. An increase in the incidence of minority mutations was detected, suggesting that less common HIV-1 variants circulating in Puerto Rico may grow rapidly in subsequent years. This observation may be validated once the corresponding data are included in the analysis. More information is needed before an ascending tendency of minority mutations can be established with certainty.