Recurrent tuberculosis from 1992 to 2004 in a metropolitan area

Abstract

The proportion of recurrent tuberculosis (TB) cases caused by re-infection has varied widely in previous studies. The aim of the present study was to determine the relative frequency of relapse and exogenous re-infection in patients with second episodes of TB, using DNA fingerprinting.A population-based retrospective longitudinal descriptive study was conducted in Madrid (Spain) during 1992-2004. The study consisted of 645 patients with culture-confirmed TB. Of these, 20 (3.1%) were retained because they presented with a second isolate of Mycobacterium tuberculosis. Finally, 12 of these cases were excluded because they did not complete the full treatment prescribed. All strains were typed by restriction fragment length polymorphism analysis and some by mycobacterial interspersed repetitive unit-variable number of tandem repeats analysis. The patients with recurrent TB were compared with those without recurrent TB.For seven out of the eight patients, the restriction fragment length polymorphism patterns of the Mycobacterium tuberculosis strains from the episodes of recurrent disease showed identical initial and final genotypes, indicating relapse; the remaining recurrent case showed different genotypes, suggesting exogenous re-infection.Re-infection is possible among people in developed countries, but the rates are lower than those occurring in high-risk areas. The risk factors for recurrent tuberculosis should be taken into account in the follow-up of treatment and tuberculosis control strategies.

The changing pattern of tuberculosis and HIV co‐infection in immigrants and Spaniards in the last 20 years

“…Immigrants usually come from countries with a higher prevalence of TB than Spain; therefore, exogenous re-infection is less likely in Spain than in their respective home countries [25]. Besides that, many of the IVDUs may have died, reducing the pool of IVDUs who could have either exogenous or endogenous TB infection.…”

Could neutrophil to lymphocyte ratio be a prognostic predictor of relapse in patients with extra-pulmonary tuberculosis?

“…Of the factors determined to be predictive of tuberculosis recurrence, HIV-infection and immune-suppression have been previously identified in countries of high and low TB incidence where most recurrences after successful TB treatment are due to endogenous reactivation (10,11). In fact, the physiological immune responses of circulating leukocytes to various stressful events are characterized by an increased neutrophil count and decreased lymphocyte count (12).…”

A nested case-control study on relapse predictors among tuberculosis patients treated in Yemen's NTCP

“…[12][13][14] In areas of low TB incidence, relapse is usually due to endogenous reactivation. [15][16][17] In areas of high TB incidence, however, the incidence of relapse attributed to re-infection can reach 75%. 12,18,19 Yemen is a low TB incidence country, with an estimated rate of 25 cases/ 100 000.…”

“…17,23,27 The association between cavitation and relapse could be attributed to poor drug penetration into the devascularised cavities or the surrounding fi brotic tissue. 27 Our study shows that weight gain is strongly associated with TB relapse, supporting the fi ndings of Khan et al 28 However, weight loss was also significantly associated with increased risk for relapse, corroborating the fi ndings of Benator et al 27 The positive association between diabetes and TB has been reported previously.…”

“…Comparable fi ndings have been reported in the literature. 17,20,21,24 The mechanism proposed to explain the association between smoking and TB is the neutralisation of tumour necrosis factor alpha (TNF-α) by substances found in tobacco. 25 The reduction in TNF-α and nitric acid, which play a role in containing the intracellular growth of M. tuberculosis, may be explained by the high level of iron in the bronchoalveolar macrophages of smokers.…”