Bacterial risk factors for treatment failure and relapse among patients with isoniazid resistant tuberculosis.

Background: Drug resistant tuberculosis (TB) is increasing in prevalence worldwide. Treatment failure and relapse is known to be high for patients with isoniazid resistant TB treated with standard first line regimens. However, risk factors for unfavourable outcomes and the optimal treatment regimen for isoniazid resistant TB are unknown.

Performance of the TB-LAMP diagnostic assay in reference laboratories: Results from a multicentre study.

Objective: To evaluate the diagnostic performance of TB-LAMP, a manual molecular tuberculosis (TB) detection method, and provide comparison to the Xpert MTB/RIF assay.

Methods: In a large multicentre study, two sputum samples were collected from participants with TB symptoms in reference laboratories in Peru, South Africa, Brazil, and Vietnam. Each sample was tested with TB-LAMP.

Molecular analysis of pyrazinamide resistance in Mycobacterium tuberculosis in Vietnam highlights the high rate of pyrazinamide resistance-associated mutations in clinical isolates.

Pyrazinamide (PZA) is a key antibiotic in current anti-tuberculosis regimens. Although the WHO has stressed the urgent need to obtain data on PZA resistance, in high tuberculosis burden countries, little is known about the level of PZA resistance, the genetic basis of such resistance or its link with Mycobacterium tuberculosis families. In this context, this study assessed PZA resistance through the molecular analysis of 260 Vietnamese M.

Drug resistance and Mycobacterium tuberculosis strain diversity in TB/HIV co-infected patients in Ho Chi Minh city, Vietnam.

Background: Mycobacterium tuberculosis strain diversity and drug resistance among people living with human immunodeficiency virus (HIV) in Vietnam have not been described previously.

Methods: We examined M. tuberculosis isolates from TB/HIV co-infected patients in Ho Chi Minh City, Vietnam.

Intensified Antituberculosis Therapy in Adults with Tuberculous Meningitis.

Background: Tuberculous meningitis is often lethal. Early antituberculosis treatment and adjunctive treatment with glucocorticoids improve survival, but nearly one third of patients with the condition still die. We hypothesized that intensified antituberculosis treatment would enhance the killing of intracerebral Mycobacterium tuberculosis organisms and decrease the rate of death among patients.

Prospective evaluation of GeneXpert for the diagnosis of HIV- negative pediatric TB cases.

Background: The GeneXpertMTB/RIF (Xpert) assay is now recommended by WHO for diagnosis of tuberculosis (TB) in children but evaluation data is limited.

Methods: One hundred and fifty consecutive HIV negative children (<15 years of age) presenting with suspected TB were enrolled at a TB referral hospital in Ho Chi Minh City, Vietnam. 302 samples including sputum (n = 79), gastric fluid (n = 215), CSF (n = 3), pleural fluid (n = 4) and cervical lymphadenopathic pus (n = 1) were tested by smear, automated liquid culture (Bactec MGIT) and Xpert.

Randomised pharmacokinetic trial of rifabutin with lopinavir/ritonavir-antiretroviral therapy in patients with HIV-associated tuberculosis in Vietnam.

Background: Rifampicin and protease inhibitors are difficult to use concomitantly in patients with HIV-associated tuberculosis because of drug-drug interactions. Rifabutin has been proposed as an alternative rifamycin, but there is concern that the current recommended dose is suboptimal. The principal aim of this study was to compare bioavailability of two doses of rifabutin (150 mg three times per week and 150 mg daily) in patients with HIV-associated tuberculosis who initiated lopinavir/ritonavir-based antiretroviral therapy in Vietnam.

Epidemiology of isoniazid resistance mutations and their effect on tuberculosis treatment outcomes.

Isoniazid resistance is highly prevalent in Vietnam. We investigated the molecular and epidemiological characteristics and the association with first-line treatment outcomes of the main isoniazid resistance mutations in Mycobacterium tuberculosis in codon 315 of the katG and in the promoter region of the inhA gene. Mycobacterium tuberculosis strains with phenotypic resistance to isoniazid from consecutively diagnosed smear-positive tuberculosis patients in rural Vietnam were subjected to Genotype MTBDRplus testing to identify katG and inhA mutations.

Tuberculosis relapse in Vietnam is significantly associated with Mycobacterium tuberculosis Beijing genotype infections.

Background: In Vietnam, the Mycobacterium tuberculosis Beijing genotype is associated with multi-drug resistance and is emerging. A possible explanation for this genotype's success is an increased rate of relapse.

Methods: In a prospective cohort study, isolates from patients with smear-positive tuberculosis were subjected to drug susceptibility testing and to spoligotyping and variable number of tandem repeats typing before treatment and after recurrence of tuberculosis.

Clustering of Beijing genotype Mycobacterium tuberculosis isolates from the Mekong delta in Vietnam on the basis of variable number of tandem repeat versus restriction fragment length polymorphism typing.

Background: In comparison to restriction fragment length polymorphism (RFLP) typing, variable number of tandem repeat (VNTR) typing is easier to perform, faster and yields results in a simple, numerical format. Therefore, this technique has gained recognition as the new international gold standard in typing of Mycobacterium tuberculosis. However, some reports indicated that VNTR typing may be less suitable for Beijing genotype isolates.

Evaluation of Xpert MTB/RIF and MODS assay for the diagnosis of pediatric tuberculosis.

Background: Tuberculosis (TB) in children is rarely confirmed due to the lack of effective diagnostic tools; only 10 to 15% of pediatric TB is smear positive due to paucibacillary samples and the difficulty of obtaining high-quality specimens from children. We evaluate here the accuracy of Xpert MTB/RIF in comparison with the Micoroscopic observation drug susceptibility (MODS) assay for diagnosis of TB in children using samples stored during a previously reported evaluation of the MODS assay.

Methods: Ninety-six eligible children presenting with suspected TB were recruited consecutively at Pham Ngoc Thach Hospital in Ho Chi Minh City Viet Nam between May to December 2008 and tested by Ziehl-Neelsen smear, MODS and Mycobacterial growth Indicator (MGIT, Becton Dickinson) culture.

Increased transmission of Mycobacterium tuberculosis Beijing genotype strains associated with resistance to streptomycin: a population-based study.

Background: Studies have shown that the Mycobacterium tuberculosis Beijing genotype is an emerging pathogen that is frequently associated with drug resistance. This suggests that drug resistant Beijing strains have a relatively high transmission fitness compared to other drug-resistant strains.

Methods And Findings: We studied the relative transmission fitness of the Beijing genotype in relation to anti-tuberculosis drug resistance in a population-based study of smear-positive tuberculosis patients prospectively recruited and studied over a 4-year period in rural Vietnam.

Prevalence of hepatitis B & hepatitis C virus infections in potential blood donors in rural Vietnam.

Background & Objectives: Safe blood and blood products should be offered to all patients in need for blood transfusion. The objectives of the present study were to establish prevalence estimates for hepatitis B and hepatitis C virus infections as a foundation for safe blood transfusion in rural Vietnam, and to check the accuracy of the laboratory analysis used for hepatitis testing of blood donors in Vietnam.

Methods: A cross-sectional study was conducted in two rural communities in Quang Tri, Vietnam.

Influence of antituberculosis drug resistance and Mycobacterium tuberculosis lineage on outcome in HIV-associated tuberculous meningitis.

HIV-associated tuberculous meningitis (TBM) has high mortality. Aside from the devastating impact of multidrug resistance (MDR) on survival, little is understood about the influence of other bacterial factors on outcome. This study examined the influence of Mycobacterium tuberculosis drug resistance, bacterial lineage, and host vaccination status on outcome in patients with HIV-associated TBM.

Mixed tuberculosis infections in rural South Vietnam.

Tuberculosis patients may be infected with or have disease caused by more than one Mycobacterium tuberculosis strain, usually referred to as "mixed infections." These have mainly been observed in settings with a very high tuberculosis incidence and/or high HIV prevalence. We assessed the rate of mixed infections in a population-based study in rural Vietnam, where the prevalences of both HIV and tuberculosis are substantially lower than those in previous studies looking at mixed infections.

Nontuberculous mycobacterial disease in patients with HIV in Southeast Asia.

Rationale: Although nontuberculous mycobacteria (NTM) are widely documented as a cause of illness among HIV-infected people in the developed world, studies describing the prevalence of NTM disease among HIV-infected people in most resource-limited settings are rare.

Objectives: To evaluate the prevalence of mycobacterial disease in HIV-infected patients in Southeast Asia.

Methods: We enrolled people with HIV from three countries in Southeast Asia and collected pulmonary and extrapulmonary specimens to evaluate the prevalence of mycobacterial disease.

Timing of initiation of antiretroviral therapy in human immunodeficiency virus (HIV)--associated tuberculous meningitis.

Background: The optimal time to initiate antiretroviral therapy (ART) in human immunodeficiency virus (HIV)-associated tuberculous meningitis is unknown.

Methods: We conducted a randomized, double-blind, placebo-controlled trial of immediate versus deferred ART in patients with HIV-associated tuberculous meningitis to determine whether immediate ART reduced the risk of death. Antiretroviral drugs (zidovudine, lamivudine, and efavirenz) were started either at study entry or 2 months after randomization.

Screening test accuracy among potential blood donors of HBsAg, anti-HBc and anti-HCV to detect hepatitis B and C virus infection in rural Cambodia and Vietnam.

The aim of this study was to determine the accuracy of rapid tests for HBsAg, anti-HBc and anti-HCV in rural Cambodia and Vietnam to detect hepatitis B and C. In a cross-sectional epidemiological study of two populations of 1,200 potential blood donors in rural Cambodia and Vietnam the prevalence rates of HBsAg, anti-HBc and anti-HCV as established by enzyme immunoassay (EIA) tests were compared to rapid test outcomes. The EIA reference test results were validated by Architect Chemiluminescent Microparticle Immunoassay (CMIA) technique.

Diagnosis of pulmonary tuberculosis in HIV-positive patients by microscopic observation drug susceptibility assay.

The microscopic observation drug susceptibility assay (MODS) is a novel and promising test for the early diagnosis of tuberculosis (TB). We evaluated the MODS assay for the early diagnosis of TB in HIV-positive patients presenting to Pham Ngoc Thach Hospital for Tuberculosis and Lung Diseases in southern Vietnam. A total of 738 consecutive sputum samples collected from 307 HIV-positive individuals suspected of TB were tested by smear, MODS, and the mycobacteria growth indicator tube method (MGIT).

Bloodstream infections among HIV-infected outpatients, Southeast Asia.

Bloodstream infections (BSIs) are a major cause of illness in HIV-infected persons. To evaluate prevalence of and risk factors for BSIs in 2,009 HIV-infected outpatients in Cambodia, Thailand, and Vietnam, we performed a single Myco/F Lytic blood culture. Fifty-eight (2.

The Mycobacterium tuberculosis Beijing genotype does not affect tuberculosis treatment failure in Vietnam.

Background: Studies have suggested that the Mycobacterium tuberculosis Beijing genotype causes more severe clinical disease and higher treatment failure rates with standard regimens, possibly in association with an increased risk of acquiring drug resistance. We studied the effect of genotype on treatment failure in a rural area in Vietnam where multidrug resistance is strongly associated with the Beijing genotype.

Methods: In a population-based prospective cohort study, patients with smear-positive tuberculosis were tested before and after treatment by spoligotyping and drug susceptibility analysis.

Evaluation of the MTBDRsl test for detection of second-line-drug resistance in Mycobacterium tuberculosis.

The MTBDRsl assay (Hain Lifescience GmbH, Germany) is a new line probe assay for the detection of extensively drug-resistant tuberculosis (XDR TB). The test simultaneously detects resistance to ethambutol, aminoglycosides/cyclic peptides, and fluoroquinolones through detection of mutations in the relevant genes. The assay format is identical to the MTBDR Hain assay.

Validation of the GenoType MTBDRplus assay for diagnosis of multidrug resistant tuberculosis in South Vietnam.

Background: To control multidrug resistant tuberculosis (MDR-TB), the drug susceptibility profile is needed to guide therapy. Classical drug susceptibility testing (DST) may take up to 2 to 4 months. The GenoType MTBDRplus test is a commercially available line-probe assay that rapidly detects Mycobacterium tuberculosis (MTB) complex, as well as the most common mutations associated with rifampin and isoniazid resistance.

Microscopic observation drug susceptibility assay (MODS) for early diagnosis of tuberculosis in children.

MODS is a novel liquid culture based technique that has been shown to be effective and rapid for early diagnosis of tuberculosis (TB). We evaluated the MODS assay for diagnosis of TB in children in Viet Nam. 217 consecutive samples including sputum (n = 132), gastric fluid (n = 50), CSF (n = 32) and pleural fluid (n = 3) collected from 96 children with suspected TB, were tested by smear, MODS and MGIT.