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Molecular characterisation of Mycobacterium tuberculosis isolates in the First National Survey of Anti-tuberculosis Drug Resistance from Venezuela.

Aristimuño L, Armengol R, Cebollada A, España M, Guilarte A, Lafoz C, Lezcano MA, Revillo MJ, Martín C, Ramírez C, Rastogi N, Rojas J, de Salas AV, Sola C, Samper S - BMC Microbiol. (2006)

Bottom Line: The results were compared with the international spoligotyping database (SpolDB4).Two clusters were found to be identical by the four different analysis methods, presumably representing cases of recent transmission of MDR tuberculosis.It may aid in the creation of a national database that will be a valuable support for further studies.

View Article: PubMed Central - HTML - PubMed

Affiliation: Escuela de Medicina, Universidad Centroccidental Lisandro Alvarado, Venezuela. lisearistimuno@yahoo.es

ABSTRACT

Background: Molecular typing of Mycobacterium tuberculosis strains has become a valuable tool in the epidemiology of tuberculosis (TB) by allowing detection of outbreaks, tracking of epidemics, identification of genotypes and transmission events among patients who would have remained undetected by conventional contact investigation. This is the first genetic biodiversity study of M. tuberculosis in Venezuela. Thus, we investigated the genetic patterns of strains isolated in the first survey of anti-tuberculosis drug-resistance realised as part of the Global Project of Anti-tuberculosis Drug Resistance Surveillance (WHO/IUATLD).

Results: Clinical isolates (670/873) were genotyped by spoligotyping. The results were compared with the international spoligotyping database (SpolDB4). Multidrug resistant (MDR) strains (14/18) were also analysed by IS6110-RFLP assays, and resistance to isoniazid and rifampicin was characterised. Spoligotyping grouped 82% (548/670) of the strains into 59 clusters. Twenty new spoligotypes (SITs) specific to Venezuela were identified. Eight new inter-regional clusters were created. The Beijing genotype was not found. The genetic network shows that the Latin American and Mediterranean family constitutes the backbone of the genetic TB population-structure in Venezuela, responsible of >60% of total TB cases studied. MDR was 0.5% in never treated patients and 13.5% in previously treated patients. Mutations in rpoB gene and katG genes were detected in 64% and 43% of the MDR strains, respectively. Two clusters were found to be identical by the four different analysis methods, presumably representing cases of recent transmission of MDR tuberculosis.

Conclusion: This study gives a first overview of the M. tuberculosis strains circulating in Venezuela during the first survey of anti-tuberculosis drug-resistance. It may aid in the creation of a national database that will be a valuable support for further studies.

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Related in: MedlinePlus

Genetic network of spoligotypes detected in Venezuela using parsimony principles and the Biolayout software. Each black arrow represents a phylogenetic link between two spoligotypes differing by a genetic change. The size of the circles representing the spoligotypes is proportional to the number of isolates in each cluster. Prevalent phylogenetic clades in Venezuela: LAM (2-9-5); T-1; Haarlem (H-1) and S are named. See text for details.
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Figure 2: Genetic network of spoligotypes detected in Venezuela using parsimony principles and the Biolayout software. Each black arrow represents a phylogenetic link between two spoligotypes differing by a genetic change. The size of the circles representing the spoligotypes is proportional to the number of isolates in each cluster. Prevalent phylogenetic clades in Venezuela: LAM (2-9-5); T-1; Haarlem (H-1) and S are named. See text for details.

Mentions: We used Biolayout software to build a genetic network of the SITs detected in Venezuela (Fig. 2) [22]. In this model, the size of the circles indicating the SIT is proportional to their quantitative distribution in this study. We used maximum parsimony principles and assumed an underlying evolution model of the DR locus by deletion of single or contiguous direct variable repeats (DVRs) to link most, if not all, of the spoligotypes found in this study. Each arrow represents a phylogenetic link between two spoligotypes that differ by a genetic change, whether this change corresponds to single or many contiguous DVRs deletion. Fig 2 shows the phylogenetic clades prevalents as well as that three variants of the LAM family – LAM2 (SIT17), LAM9 (SIT42), and LAM5 (SIT93) – constitute the backbone of the genetic TB population-structure in Venezuela. A more detailed picture will require further investigations using complementary genetic markers.


Molecular characterisation of Mycobacterium tuberculosis isolates in the First National Survey of Anti-tuberculosis Drug Resistance from Venezuela.

Aristimuño L, Armengol R, Cebollada A, España M, Guilarte A, Lafoz C, Lezcano MA, Revillo MJ, Martín C, Ramírez C, Rastogi N, Rojas J, de Salas AV, Sola C, Samper S - BMC Microbiol. (2006)

Genetic network of spoligotypes detected in Venezuela using parsimony principles and the Biolayout software. Each black arrow represents a phylogenetic link between two spoligotypes differing by a genetic change. The size of the circles representing the spoligotypes is proportional to the number of isolates in each cluster. Prevalent phylogenetic clades in Venezuela: LAM (2-9-5); T-1; Haarlem (H-1) and S are named. See text for details.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1621067&req=5

Figure 2: Genetic network of spoligotypes detected in Venezuela using parsimony principles and the Biolayout software. Each black arrow represents a phylogenetic link between two spoligotypes differing by a genetic change. The size of the circles representing the spoligotypes is proportional to the number of isolates in each cluster. Prevalent phylogenetic clades in Venezuela: LAM (2-9-5); T-1; Haarlem (H-1) and S are named. See text for details.
Mentions: We used Biolayout software to build a genetic network of the SITs detected in Venezuela (Fig. 2) [22]. In this model, the size of the circles indicating the SIT is proportional to their quantitative distribution in this study. We used maximum parsimony principles and assumed an underlying evolution model of the DR locus by deletion of single or contiguous direct variable repeats (DVRs) to link most, if not all, of the spoligotypes found in this study. Each arrow represents a phylogenetic link between two spoligotypes that differ by a genetic change, whether this change corresponds to single or many contiguous DVRs deletion. Fig 2 shows the phylogenetic clades prevalents as well as that three variants of the LAM family – LAM2 (SIT17), LAM9 (SIT42), and LAM5 (SIT93) – constitute the backbone of the genetic TB population-structure in Venezuela. A more detailed picture will require further investigations using complementary genetic markers.

Bottom Line: The results were compared with the international spoligotyping database (SpolDB4).Two clusters were found to be identical by the four different analysis methods, presumably representing cases of recent transmission of MDR tuberculosis.It may aid in the creation of a national database that will be a valuable support for further studies.

View Article: PubMed Central - HTML - PubMed

Affiliation: Escuela de Medicina, Universidad Centroccidental Lisandro Alvarado, Venezuela. lisearistimuno@yahoo.es

ABSTRACT

Background: Molecular typing of Mycobacterium tuberculosis strains has become a valuable tool in the epidemiology of tuberculosis (TB) by allowing detection of outbreaks, tracking of epidemics, identification of genotypes and transmission events among patients who would have remained undetected by conventional contact investigation. This is the first genetic biodiversity study of M. tuberculosis in Venezuela. Thus, we investigated the genetic patterns of strains isolated in the first survey of anti-tuberculosis drug-resistance realised as part of the Global Project of Anti-tuberculosis Drug Resistance Surveillance (WHO/IUATLD).

Results: Clinical isolates (670/873) were genotyped by spoligotyping. The results were compared with the international spoligotyping database (SpolDB4). Multidrug resistant (MDR) strains (14/18) were also analysed by IS6110-RFLP assays, and resistance to isoniazid and rifampicin was characterised. Spoligotyping grouped 82% (548/670) of the strains into 59 clusters. Twenty new spoligotypes (SITs) specific to Venezuela were identified. Eight new inter-regional clusters were created. The Beijing genotype was not found. The genetic network shows that the Latin American and Mediterranean family constitutes the backbone of the genetic TB population-structure in Venezuela, responsible of >60% of total TB cases studied. MDR was 0.5% in never treated patients and 13.5% in previously treated patients. Mutations in rpoB gene and katG genes were detected in 64% and 43% of the MDR strains, respectively. Two clusters were found to be identical by the four different analysis methods, presumably representing cases of recent transmission of MDR tuberculosis.

Conclusion: This study gives a first overview of the M. tuberculosis strains circulating in Venezuela during the first survey of anti-tuberculosis drug-resistance. It may aid in the creation of a national database that will be a valuable support for further studies.

Show MeSH
Related in: MedlinePlus