Characterisation of Mycobacterium tuberculosis isolates lacking IS6110 in Viet Nam.
Int J Tuberc Lung Dis
; 17(11): 1479-85, 2013 Nov.
Article
in En
| MEDLINE
| ID: mdl-24125454
ABSTRACT
SETTING:
The molecular diagnosis of tuberculosis (TB) in Viet Nam is often based on the detection of insertion sequence (IS) 6110 in Mycobacterium tuberculosis. However, 8-11% of M. tuberculosis strains in South-East Asia do not contain this target and this undermines the validity of these molecular tests.OBJECTIVE:
We quantified the frequency of M. tuberculosis strains lacking IS6110 in rural Viet Nam and studied their epidemiological and clinical characteristics.DESIGN:
Consecutively diagnosed adult TB patients in rural Southern Viet Nam submitted two sputum samples for culture, IS6110 restriction fragment length polymorphism (RFLP) spoligotyping and 15-loci variable number tandem repeat typing. Polymerase chain reaction (PCR) was performed to confirm the absence of IS6110 elements in strains lacking IS6110 hybridisation in RFLP.RESULTS:
Among 2664 TB patient isolates examined, 109 (4.1%) had no IS6110 element. Compared to other strains, these no-copy strains were less often resistant to anti-tuberculosis drugs, particularly to streptomycin (adjusted OR 0.2, 95%CI 0.1-0.5), and showed significant geographic variation. No associations with TB history or demographic factors were found.CONCLUSIONS:
Strains without the IS6110 target pose a problem in Viet Nam as regards false-negative molecular TB diagnosis in PCR. Compared to other strains circulating in Viet Nam, no-copy strains are more susceptible to anti-tuberculosis drugs.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Tuberculosis, Pulmonary
/
DNA, Bacterial
/
DNA Transposable Elements
/
Mycobacterium tuberculosis
Type of study:
Diagnostic_studies
/
Observational_studies
/
Prognostic_studies
/
Risk_factors_studies
Limits:
Adolescent
/
Adult
/
Aged
/
Female
/
Humans
/
Male
/
Middle aged
Country/Region as subject:
Asia
Language:
En
Journal:
Int J Tuberc Lung Dis
Year:
2013
Document type:
Article