The interrelationship of strain diversity, virulence and patient ethnicity for tuberculosis in the Midlands, UK

Smith, Helen Elizabeth (2013). The interrelationship of strain diversity, virulence and patient ethnicity for tuberculosis in the Midlands, UK. University of Birmingham. Ph.D.

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This study examined the relationship between Mycobacterium tuberculosis global clades and patient origin. In the UK, the rate of tuberculosis is higher amongst patients who originated from the Indian subcontinent (ISC), where two dominant lineages are present, the Central Asian Strain (CAS) and the East African Indian (EAI) lineage. Mycobacterial interspersed units containing variable number of tandem repeats DNA fingerprinting of M. tuberculosis strains isolated from UK patients who originated from the ISC, as defined by novel software, identified that CAS was the most prevalent clade (39%) and EAI was the third most prevalent clade (15%). To further elucidate the relationship between host origin and strain lineage, two rigorous new models of infection were developed which assessed mycobacterial growth and host cell response. The monocyte-derived macrophage model was more appropriate for measuring cytototoxicity than the THP-1 cell model as in the absence of infection, 50% of THP-1 cells died compared to 2% of macrophages. CAS strains caused 1.5 fold more cell necrosis and their growth was four fold higher than EAI strains in the monocyte-derived macrophage model. Finally, the response of polarised monocyte-derived macrophages from Asian and Caucasian donors to different M. tuberculosis lineages was compared. CAS strains grew preferentially better in M2 macrophages from Asian donors. The prevalence of CAS in the Midlands is likely to be due to a combination of specific strain importation and increased ability of this strain to transmit to the population present in the Midlands.

Type of Work: Thesis (Doctorates > Ph.D.)
Award Type: Doctorates > Ph.D.
College/Faculty: Colleges (2008 onwards) > College of Medical & Dental Sciences
School or Department: School of Immunity and Infection
Funders: None/not applicable
Subjects: Q Science > QR Microbiology
Q Science > QR Microbiology > QR180 Immunology
R Medicine > RC Internal medicine


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