Evaluation of microscopic observation drug susceptibility assay for diagnosis of multidrug-resistant tuberculosis in Viet Nam.

Background: Early diagnosis of tuberculosis (TB) and multidrug resistant tuberculosis (MDR TB) is important for the elimination of TB. We evaluated the microscopic observation drug susceptibility (MODS) assay as a direct rapid drug susceptibility testing (DST) method for MDR-TB screening in sputum samples

Methods: All adult TB suspects, who were newly presenting to Pham Ngoc Thach Hospital from August to November 2008 were enrolled into the study. Processed sputum samples were used for DST by MODS (DST-MODS) (Rifampicin (RIF) 1 μg/ml and Isoniazid (INH) 0.

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).

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.

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.

Beijing genotype of Mycobacterium tuberculosis is significantly associated with high-level fluoroquinolone resistance in Vietnam.

Consecutive fluoroquinolone (FQ)-resistant isolates (n = 109) identified at the Pham Ngoc Thach Hospital for Tuberculosis, Ho Chi Minh City, Vietnam, were sequenced in the quinolone resistance-determining regions of the gyrA and gyrB genes and typed by large sequence polymorphism typing and spoligotyping to identify the Beijing genotype of Mycobacterium tuberculosis. Beijing genotype prevalence was compared with 109 consecutive isolates from newly presenting patients with pulmonary tuberculosis from the hospital outpatient department. Overall, 82.

PCR-restriction fragment length polymorphism for rapid, low-cost identification of isoniazid-resistant Mycobacterium tuberculosis.

PCR-restriction fragment length poymorphism (PCR-RFLP) is a simple, robust technique for the rapid identification of isoniazid-resistant Mycobacterium tuberculosis. One hundred consecutive isolates from a Vietnamese tuberculosis hospital were tested by MspA1I PCR-RFLP for the detection of isoniazid-resistant katG_315 mutants. The test had a sensitivity of 80% and a specificity of 100% against conventional phenotypic drug susceptibility testing.

Mutations prevalent among rifampin- and isoniazid-resistant Mycobacterium tuberculosis isolates from a hospital in Vietnam.

Vietnam is ranked 13th among the WHO list of 22 high-burden countries, based upon estimated total number of tuberculosis cases. Despite having a model national tuberculosis program, consistently achieving and exceeding WHO targets for detection and cure, drug-resistant and multidrug-resistant tuberculosis cases continue to rise. Rapid multidrug-resistant tests applicable in this setting, coupled with effective treatment regimens, would be a useful tool in reversing this trend, allowing early identification of patients with multidrug-resistant tuberculosis and avoiding resistance-amplifying regimens.