Tuberculosis 2: Pathophysiology and microbiology of pulmonary tuberculosis

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Clinical manifestations of pulmonary and extra-pulmonary tuberculosis

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Tuberculosis 1. Epidemiology of mycobacterium tuberculosis

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A Geographically-Restricted but Prevalent Mycobacterium tuberculosis Strain Identified in the West Midlands Region of the UK between 1995 and 2008

Background: We describe the identification of, and risk factors for, the single most prevalent Mycobacterium tuberculosis strain in the West Midlands region of the UK.Methodology/Principal Findings: Prospective 15-locus MIRU-VNTR genotyping of all M. tuberculosis isolates in the West Midlands between 2004 and 2008 was undertaken. Two retrospective epidemiological investigations were also undertaken using univariable and multivariable logistic regression analysis. The first study of all TB patients in the West Midlands between 2004 and 2008 identified a single prevalent strain in each of the study years (total 155/3,056 (5%) isolates). This prevalent MIRU-VNTR profile (32333 2432515314 434443183) remained clustered after typing with an additional 9-loci MIRU-VNTR and spoligotyping. The majority of these patients (122/155, 79%) resided in three major cities located within a 40 km radius. From the apparent geographical restriction, we have named this the "Mercian" strain. A multivariate analysis of all TB patients in the West Midlands identified that infection with a Mercian strain was significantly associated with being UK-born (OR = 9.03, 95% CI = 4.56-17.87, p 65 years old (OR = 0.25, 95% CI = 0.09-0.67, p < 0.01). A second more detailed investigation analyzed a cohort of 82 patients resident in Wolverhampton between 2003 and 2006. A significant association with being born in the UK remained after a multivariate analysis (OR = 9.68, 95% CI = 2.00-46.78, p < 0.01) and excess alcohol intake and cannabis use (OR = 6.26, 95% CI = 1.45-27.02, p = .01) were observed as social risk factors for infection.Conclusions/Significance: The continued consistent presence of the Mercian strain suggests ongoing community transmission. Whilst significant associations have been found, there may be other common risk factors yet to be identified. Future investigations should focus on targeting the relevant risk groups and elucidating the biological factors that mediate continued transmission of this strain

Clinical manifestations of pulmonary and extra-pulmonary tuberculosis

The clinical manifestations of tuberculosis are dependent on a number of factors: age, immune status, co-existing diseases, immunization status to the bacillus Calmette-Guerin (BCG); virulence of the infecting organism and host-microbe interaction. Before the advent of the HIV epidemic, approximately 85% of reported tuberculosis cases were pulmonary only, with the remaining 15% being extra-pulmonary or both pulmonary and extra-pulmonary sites [1]. One large retrospective study [2] of tuberculosis in patients with advanced HIV infection reported: Pulmonary involvement alone 38%, Extrapulmonary sites alone 30%, Both pulmonary and nonpulmonary 32

Tuberculosis 2: Pathophysiology and microbiology of pulmonary tuberculosis

Inhalation of Mycobacterium tuberculosis leads to one of four possible outcomes: Immediate clearance of the organism Latent infection The onset of active disease (primary disease) Active disease many years later (reactivation disease). Among individuals with latent infection, and no underlying medical problems, reactivation disease occurs in 5 to 10 percent of cases [1]. The risk of reactivation is markedly increased in patients with HIV [2]. These outcomes are determined by the interplay of factors attributable to both the organism and the host

Invasive shigellosis in MSM.

Shigella flexneri is an emerging pathogen in men who have sex with men (MSM); recent outbreaks related to sexual practices have been noted in this population in the UK and other developed countries. While the majority of cases of shigellosis present with gastroenteritis, some vulnerable patients with underlying immunosuppression can develop complications like bacteraemia and may present atypically as an acute surgical emergency. This case report highlights such a case of S. flexneri bacteraemia in a man who had sex with men