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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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IS6110 RFLP, katG and rpoB gene mutations of 14 MDR isolates clustered by Spoligotyping. Dendogram based on the Spoligotyping method of 14 MDR strains showing the IS6110 RFLP, the codon 315 in katG gene (0: No Ser315Thr mutation, 1: Ser315Thr) and rpoB gene mutations (1: No mutation, 6: Asp516Val/GAC-GTC, 10: Ser531Leu/TCG-TTG). Strain: identification of the isolate. State: origin of the isolate. SIT: spoligo-international type number [19].
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Figure 3: IS6110 RFLP, katG and rpoB gene mutations of 14 MDR isolates clustered by Spoligotyping. Dendogram based on the Spoligotyping method of 14 MDR strains showing the IS6110 RFLP, the codon 315 in katG gene (0: No Ser315Thr mutation, 1: Ser315Thr) and rpoB gene mutations (1: No mutation, 6: Asp516Val/GAC-GTC, 10: Ser531Leu/TCG-TTG). Strain: identification of the isolate. State: origin of the isolate. SIT: spoligo-international type number [19].

Mentions: We analysed 14 (78%) of the 18 isolates identified as MDR using phenotypic methods. While Spoligotyping grouped 10 strains in 2 clusters (SITs 17 and 42) and 4 unique isolates were identified as SIT 60, 130, 1705 and 0 (orphan pattern), RFLP analysis classified eight (57%) isolates as unique, with the other six (43%) isolates being grouped into three clusters of two isolates (Fig 3). The number of IS6110 per strain varied from 9 to 15. Of the three clusters, two contained isolates from patients from two different states and one cluster contained isolates from patients living in the same state (Fig 3). We investigated these isolates to identify the mutation associated with INH resistance (katG gene) and RIF resistance (rpoB gene). As summarized in the Fig 3, we found the Ser315Thr mutation in the katG gene in 6 (43%) of the 14 isolates, identified as: VEN 479, 624, 769, 605, 611 and 617.


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)

IS6110 RFLP, katG and rpoB gene mutations of 14 MDR isolates clustered by Spoligotyping. Dendogram based on the Spoligotyping method of 14 MDR strains showing the IS6110 RFLP, the codon 315 in katG gene (0: No Ser315Thr mutation, 1: Ser315Thr) and rpoB gene mutations (1: No mutation, 6: Asp516Val/GAC-GTC, 10: Ser531Leu/TCG-TTG). Strain: identification of the isolate. State: origin of the isolate. SIT: spoligo-international type number [19].
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: IS6110 RFLP, katG and rpoB gene mutations of 14 MDR isolates clustered by Spoligotyping. Dendogram based on the Spoligotyping method of 14 MDR strains showing the IS6110 RFLP, the codon 315 in katG gene (0: No Ser315Thr mutation, 1: Ser315Thr) and rpoB gene mutations (1: No mutation, 6: Asp516Val/GAC-GTC, 10: Ser531Leu/TCG-TTG). Strain: identification of the isolate. State: origin of the isolate. SIT: spoligo-international type number [19].
Mentions: We analysed 14 (78%) of the 18 isolates identified as MDR using phenotypic methods. While Spoligotyping grouped 10 strains in 2 clusters (SITs 17 and 42) and 4 unique isolates were identified as SIT 60, 130, 1705 and 0 (orphan pattern), RFLP analysis classified eight (57%) isolates as unique, with the other six (43%) isolates being grouped into three clusters of two isolates (Fig 3). The number of IS6110 per strain varied from 9 to 15. Of the three clusters, two contained isolates from patients from two different states and one cluster contained isolates from patients living in the same state (Fig 3). We investigated these isolates to identify the mutation associated with INH resistance (katG gene) and RIF resistance (rpoB gene). As summarized in the Fig 3, we found the Ser315Thr mutation in the katG gene in 6 (43%) of the 14 isolates, identified as: VEN 479, 624, 769, 605, 611 and 617.

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