Associations betweenMycobacterium tuberculosisStrains and Phenotypes

Abstract

This population-based study was used to investigate strong associations between phenotypes and genotypes.

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

“…Additional data from other groups also indicate that RD Rio could be associated with drug resistance. Gavín et al described MDR strains of M. tuberculosis RD Rio sublineage (LAM9 subfamily) in Spain from Equatorial Guinean patients (39), and Brown et al showed that LAM1 (a marker for RD Rio ) was associated with resistance to both pyrazinamide and streptomycin in MTB cases from London, United Kingdom (33), while the study performed in New York, NY, demonstrated that RD Rio was associated with resistance to isoniazid (24). Although this is a matter of speculation, it is interesting that a strain from LAM4, a subfamily that contains both WT and RD Rio strains, is the major cause of XDR-TB in South Africa (17) and that both LAM9 (predominantly RD Rio but also containing WT) and LAM1 (exclusively RD Rio ) subfamilies were major contributors to drug resistance in Russia (14,16).…”

“…As examples, we mention strains within the W/Beijing spoligotype that produce a modified phenoglycolipid associated with an insertion in the pks15/1 gene and dampened induction of interleukin-6 (IL-6), IL-12, and tumor necrosis factor (TNF) (30,31) and the CDC1551 strain that is associated with inducing a higher proinflammatory response (32). One of the mechanisms of Mycobacterium that could underlie the evasion from the host immune response is alteration of expression of the genes belonging to the PPE/PE_PGRS family, encoding surface proteins associated with mycobacterial virulence and host immune response (1,33,34). We previously speculated that in M. tuberculosis strains with the RD Rio deletion, the loss of two PPE genes (PPE55 and PPE56) could minimize host immune recognition, leading to enhanced virulence and/or transmissibility (21).…”

Microevolution of extensively drug-resistant tuberculosis in Russia

“…Over 10 years, this strain grew from causing a few cases, to dominate the country's M. tuberculosis population (Kruuner et al 2001). Brown et al (2010) have demonstrated that global MTBC diversity is reflected in strains circulating in London. Based on VNTR typing, 23 London isolates were selected to represent maximum variability across the entire MTBC and particularly within the Beijing lineage.…”

Mixed-Strain Mycobacterium tuberculosis Infections among Patients Dying in a Hospital in KwaZulu-Natal, South Africa

“…The application of molecular approaches for detecting variation among Mycobacterium tuberculosis isolates has generated new appreciation for the diversity present within this relatively genetically conserved bacterial species (4,17). Genotyping methods, such as insertion sequence typing (IS6110), spacer oligonucleotide typing (spoligotyping), and mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) typing, have been used to identify transmission chains (1,10,18,26), to classify strains into families and lineages (2,5,9,18,27,29), to identify episodes of exogenous reinfection (3,20,25,31), and, most recently, to detect the presence of within-host genetic heterogeneity (11,19,24,33).…”