Comparison of Xpert MTB/RIF Assay and the Conventional Sputum Microscopy in Detecting Mycobacterium tuberculosis in Northern Thailand.

Background. Despite low sensitivity in detection of Mycobacterium tuberculosis, sputum acid-fast smear remains the main diagnostic method. This study aimed to compare the diagnostic performance of Xpert MTB/RIF assay versus conventional sputum acid-fast smear. Materials and Methods. A cross-sectional study was conducted at Chiang Mai University Hospital, Thailand. Patients who were ≥15 years old and had clinically suspected pulmonary tuberculosis were included. Results. 109 specimens from 57 patients were included. Using MGIT sputum culture as a reference standard, the sensitivity (SEN) and specificity (SPEC) for Xpert were 95.3% (95% CI, 84.2%, 99.4%) and 86.4% (95% CI, 75.7%, 93.6%). The SEN and SPEC for sputum acid-fast smear were 60.5% (95% CI, 44.4%, 75.0%) and 98.5% (95% CI, 91.8%, 100%). Xpert had significantly higher sensitivity (p value < 0.001) and lower specificity (p value = 0.022) than sputum acid-fast smear. Among 43 culture-proven M. tuberculosis specimens, sensitivity of Xpert was 100% (95% CI, 86.7%, 100%) in acid-fast positive smears (n = 26) and 88.2% (95% CI, 63.5%, 98.5%) in acid-fast negative smears (n = 17). Conclusions. The good sensitivity and specificity of Xpert assay in detecting M. tuberculosis from sputum specimens may help in early diagnosis and treatment of pulmonary tuberculosis, particularly among patients who had acid-fast negative sputum smear.

Zinc finger protein designed to target 2-long terminal repeat junctions interferes with human immunodeficiency virus integration.

Integration of the human immunodeficiency virus type 1 (HIV-1) genome into the host chromosome is a vital step in the HIV life cycle. The highly conserved cytosine-adenine (CA) dinucleotide sequence immediately upstream of the cleavage site is crucial for integrase (IN) activity. As this viral enzyme has an important role early in the HIV-1 replication cycle, interference with the IN substrate has become an attractive strategy for therapeutic intervention. We demonstrated that a designed zinc finger protein (ZFP) fused to green fluorescent protein (GFP) targets the 2-long terminal repeat (2-LTR) circle junctions of HIV-1 DNA with nanomolar affinity. We report now that 2LTRZFP-GFP stably transduced into 293T cells interfered with the expression of vesicular stomatitis virus glycoprotein (VSV-G)-pseudotyped lentiviral red fluorescent protein (RFP), as shown by the suppression of RFP expression. We also used a third-generation lentiviral vector and pCEP4 expression vector to deliver the 2LTRZFP-GFP transgene into human T-lymphocytic cells, and a stable cell line for long-term expression studies was selected for HIV-1 challenge. HIV-1 integration and replication were inhibited as measured by Alu-gag real-time PCR and p24 antigen assay. In addition, the molecular activity of 2LTRZFP-GFP was evaluated in peripheral blood mononuclear cells. The results were confirmed by Alu-gag real-time PCR for integration interference. We suggest that the expression of 2LTRZFP-GFP limited viral integration on intracellular immunization, and that it has potential for use in HIV gene therapy in the future.

Incidence of HIV and sexually transmitted infections and risk factors for acquisition among young methamphetamine users in northern Thailand.

BACKGROUND: Southeast Asia is experiencing an epidemic of methamphetamine use, a drug associated with risky sexual behaviors, putting a large segment of the population at increased risk for sexually transmitted infections (STIs) and HIV and in need of prevention efforts. Incidence estimates of STIs are rare in Southeast Asia, especially among newer risk groups. STUDY DESIGN: We enrolled methamphetamine users aged 18 to 25 years in a 12-month randomized behavioral intervention trial in Chiang Mai, Thailand in 2005. Behavioral questionnaires were administered at visits every 3 months, and biologic specimens were collected at baseline and 12 months to test for common STIs (chlamydia, gonorrhea, HSV-2, and HIV). Poisson regression with robust variance was used to determine risk factors for incident STIs. RESULTS: Overall, 12.7% of 519 participants acquired at least 1 STI. Chlamydia was the most common (10.6%), followed by HSV-2 (4.0%), gonorrhea (2.9%), and HIV (0.6%). Risk factors for both men and women included self-reported incarceration and having a casual sex partner during follow-up, and having a prevalent STI at baseline. Additionally, among women, having 2 or more heterosexual partners, and among men, having a greater frequency of drunkenness were risk factors for STI acquisition. CONCLUSIONS: Although HIV incidence is low in this population, incidence of other STIs is high compared with previous studies of young Thai adults. Risk factors for acquisition emphasize the need for new prevention strategies targeted toward current populations at risk.

Correlates of incarceration among young methamphetamine users in Chiang Mai, Thailand.

OBJECTIVES: We examined correlates of incarceration among young methamphetamine users in Chiang Mai, Thailand in 2005 to 2006. METHODS: We conducted a cross-sectional study among 1189 young methamphetamine users. Participants were surveyed about their recent drug use, sexual behaviors, and incarceration. Biological samples were obtained to test for sexually transmitted and viral infections. RESULTS: Twenty-two percent of participants reported ever having been incarcerated. In multivariate analysis, risk behaviors including frequent public drunkenness, starting to use illicit drugs at an early age, involvement in the drug economy, tattooing, injecting drugs, and unprotected sex were correlated with a history of incarceration. HIV, HCV, and herpes simplex virus type 2 (HSV-2) infection were also correlated with incarceration. CONCLUSIONS: Incarcerated methamphetamine users are engaging in behaviors and being exposed to environments that put them at increased risk of infection and harmful practices. Alternatives to incarceration need to be explored for youths.

Sexually transmitted infections and sexual and substance use correlates among young adults in Chiang Mai, Thailand.

BACKGROUND: Data on the prevalence of and associated behavioral risk factors for sexually transmitted infections (STI) in young adults in Asia have not been widely studied. STUDY DESIGN: We conducted a cross-sectional study in Chiang Mai, Thailand in 2005--2006 among 658 sexually active participants aged 18 to 25 years, the majority having a history of recent methamphetamine (MA) use. Data were collected by interview and STI were detected using standard laboratory assays. RESULTS: Overall, 38% of participants had at least one laboratory confirmed STI. Herpes simplex virus and Chlamydia were significantly more common among women, whereas hepatitis B virus was significantly more common among men. Men reported a greater number of sexual partners than women, and condom use at last sex was infrequent. Most participants reported using MA at least weekly, with men more frequent users than women, and more often giving reports of frequent drunkenness and lifetime arrests. Behavioral correlates of prevalent STI were similar to the published literature. In multivariate analysis, women > or =20 years of age, with > or =2 heterosexual partners in the past year and a younger age at sexual debut were significantly more likely to have a prevalent STI. Men > or =20 years of age, with > or =2 heterosexual partners in the past year and who enrolled both sex and drug network members were significantly more likely to have a prevalent STI, whereas men who used a condom at last sex were significantly less likely to have a prevalent STI. Substance abuse was associated with behavioral risks but not with prevalent STI. CONCLUSIONS: Sexual risks and substance abuse are substantially elevated among young Thai MA users, but only sexual risks are associated with prevalent STI.

HIV infection among female drug users in Northern Thailand.

Reports on HIV infection and risk behaviors among female drug users in developing countries, particularly in Asia, are limited. In this study, we investigated HIV prevalence and risk factors for HIV infection among 200 women admitted for 21-day inpatient drug detoxification in Chiang Mai, Thailand. Volunteers completed a face-to-face interview using a structured interview, HIV pre-test counseling, specimen collection for HIV and STD tests, and were provided test results and HIV post-test counseling 1 week later. Two-third of participants (68%) were ethnic minorities with no formal education. Overall, 14 (7%) were HIV positive: 25% among 28 heroin injectors and 4.1% among 172 opium or methamphetamine smokers (p<0.001). History of drug injection and sexual abuse were associated with HIV infection. HIV prevention strategies for drug-using women in Thailand should consider both harm reduction strategies for drug use and promoting safer sex measures in a culturally appropriate context.