Application of Sensitive and Specific Molecular Methods To Uncover Global Dissemination of the Major RD ^Rio Sublineage of the Latin American-Mediterranean Mycobacterium tuberculosis Spoligotype Family

Abstract

103 SNP RFLP, as compared to results obtained using a PCR method targeting a LAM-restricted IS6110 element, correctly identified 99.8% of LAM spoligotype strains. Together, these tests were more accurate than spoligotyping at categorizing strains with indefinable spoligotypes and segregated true LAM strains from those with convergent spoligotypes. The fact that RD Rio strains were identified worldwide highlights the importance of this LAM family sublineage and suggests that this strain is a global threat that should be specifically targeted by public health resources. Our provision of simple and robust molecular methods will assist the evaluation of the LAM family and the RD Rio sublineage.

Streptomycin Resistance and Lineage-Specific Polymorphisms in Mycobacterium tuberculosis gidB Gene

“…Spoligotypes evolve through successive loss of spacer DNA sequences (16), and since lineages are defined by spacer patterns, the independent loss of similar spacers sets can lead to the convergent evolution of spoligotypes (32). This is problematic, because not all strains may truly represent their designed spoligotype lineage (11). This may explain the discrepant result found in this study, indicating that a convergence of spoligotypes may have occurred.…”

Frequent Homologous Recombination Events in Mycobacterium tuberculosis PE/PPE Multigene Families: Potential Role in Antigenic Variability

“…1). Confirmation of the efficiency of the microarray was provided by the BCG strain, which showed no hybridization signal with 13 deleted or truncated PE/PPE genes (PE32, PE35, PE_ PGRS35, PPE38, PPE39, PPE40, PPE54, PPE57, PPE58, PPE65, PPE66, PPE67, and PPE68) (6,10,11,24).…”

Mycobacterium tuberculosis of the RD Rio Genotype Is the Predominant Cause of Tuberculosis and Associated with Multidrug Resistance in Porto Alegre City, South Brazil

“…An additional reason for studying the features of the spoligofamilies was the recent discovery of RD Rio , a subfamily inside the larger LAM spoligofamily, which seems to be prevalent in several places in Brazil (18)(19)(20)(21)(22)(23) but also in many other countries, particularly in Central and South America, Europe, and Africa (19 (24) as well as with drug resistance (24). To confirm and expand these findings, the present study was undertaken in Rio Grande do Sul (RS), the southernmost Brazilian state, for which no data on RD Rio status and characteristics exist.…”