High prevalence of latent tuberculosis infection among injection drug users in Tijuana, Mexico.

BACKGROUND: We studied prevalence and correlates of latent tuberculosis infection (LTBI) among injection drug users (IDUs) in Tijuana, Mexico, where tuberculosis (TB) is endemic. METHODS: IDUs aged > or =18 years were recruited via respondent-driven sampling (RDS) and underwent standardized interviews, human immunodeficiency virus (HIV) antibody testing and LTBI screening using Quanti-FERON((R))-TB Gold In-Tube, a whole-blood interferon-gamma release assay (IGRA). LTBI prevalence was estimated and correlates were identified using RDS-weighted logistic regression. RESULTS: Of 1020 IDUs, 681 (67%) tested IGRA-positive and 44 (4%) tested HIV-positive. Mean age was 37 years, 88% were male and 98% were Mexican-born. IGRA positivity was associated with recruitment nearest the US border (aOR 1.64, 95%CI 1.09-2.48), increasing years of injection (aOR 1.20/5 years, 95%CI 1.07-1.34), and years lived in Tijuana (aOR 1.10/5 years, 95%CI 1.03-1.18). Speaking some English (aOR 0.38, 95%CI 0.25-0.57) and injecting most often at home in the past 6 months (aOR 0.68, 95%CI 0.45-0.99) were inversely associated with IGRA positivity. DISCUSSION: Increased LTBI prevalence among IDUs in Tijuana appears to be associated with greater drug involvement. Given the high risk for HIV infection among Tijuana's IDUs, interventions are urgently needed to prevent HIV infection and treat LTBI among IDUs before these epidemics collide.

Prevalence of primary HIV-1 drug resistance in pregnant women and in newly diagnosed adults at Tijuana General Hospital, Baja California, Mexico.

At Tijuana General Hospital, between March 2003 and June 2005, pregnant women and other adults, recently identified as HIV infected, antiretroviral naïve, were enrolled to examine the prevalence of primary HIV drug resistance. All subjects had the Calypte HIV-1 BED Incidence enzyme immunoassay test to identify recent infection. Genotypic analysis of HIV-1 protease and reverse transcriptase regions in plasma was performed. Forty-six subjects participated, eight (17%) men, 38 (83%) women. Ten (22%) subjects were classified as having recent HIV infection. HIV genotype was performed in 41 subjects. One subject (2.5%) had a major mutation in the reverse transcriptase region (K219Q) conferring zidovudine resistance, one had a minor mutation at V118I (2.5%) and two subjects (5%) had minor mutation (V179D) associated with non-nucleoside reverse transcriptase inhibitor resistance. There were no major protease inhibitor-associated mutations but minor mutations were common. The prevalence of primary HIV drug resistance in Baja California is low.