A comparison of the virulence in Guinea-pigs of south indian and British tubercle bacilli

Allopatric tuberculosis host–pathogen relationships are associated with greater pulmonary impairment

“…These findings are consistent with several prior observations (Mitchison et al, 1960;Goren et al, 1974;Portevin et al, 2011;Krishnan et al, 2011). M. tuberculosis from southern India, the geographic area associated Indo-Oceanic lineages, were shown more than 50 years ago to be less virulent in guinea pigs than those collect in the United Kingdom strains (Mitchison et al, 1960). We speculate that aggressive/destructive lung damage with which we used PFT as a measure might not be an appropriate measure for virulent among "ancient" strains such as the InoOceanic lineage.…”

Genomic interrogation of ancestral Mycobacterium tuberculosis from south India

“…Starting 50 years ago, studies using the guinea pig and other animal models have repeatedly reported that strains of M. tuberculosis from south India were less virulent than other strains (Mitchison et al, 1960, Singh et al, 1964, Prabhakar et al 1987. Furthermore, BCG vaccine trails in south India showed no significant efficacy (TRC, 1999).…”

“…The tuberculosis strains isolated from south Indian patients exhibit certain phenotypic characteristics like low virulences in guineapigs, resistance to isoniazid (Mitchison et al, 1960, Middlebrook et al, 1953 thiophene-2-carboxylic acid hydrazide (TC4) and paraamino salicylic acid (PAS) (Joseph et al, 1964) enhanced susceptibility to H 2 O 2 and a majority of them belonging to intermediate phage type. (Bhatia A.L.…”

Polymorphism in the RD1 locus and its effect on downstream genes among South Indian clinical isolates of Mycobacterium tuberculosis

“…South Indian M. tuberculosis strains have a lower number of IS6110 copies and have been reported previously to be low in virulence compared with M. tuberculosis isolates from London in a guinea pig model (Mitchison et al, 1960). Rao et al (2005) used a single set of primers to amplify the 9.2 kb RD1 region and showed that all clinical strains of Indian origin tested in their study lacked this region.…”

“…Therefore, Soman et al (2007) checked whether the RD1 genes were really absent in clinical strains of Indian origin by using three sets of primers to amplify the coding regions alone. The results of the above two conflicting reports from India tempted us to explore polymorphisms of the RD1 genes in our isolates, which were reported previously to be of low virulence (Mitchison et al, 1960).…”