Recent transmission of tuberculosis involving retired patients

Cafrune, Patrícia Izquierdo; Riley, Lee W.; Possuelo, Lia Gonçalves; Valim, Andréia Rosane Moura; Borges, Michele; Ribeiro, Marta Osório; Rossetti, Maria Lúcia Rosa; Zaha, Arnaldo

doi:10.1016/j.jinf.2005.12.027

Cited by 7 publications

(3 citation statements)

References 26 publications

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“…However, as the annual risk of infection in the Rio de Janeiro region had not greatly changed during the last decade (Cavalcante et al 2003), this study may provide reliable positive predictive values for clusters. Two main characteristics of the Mtb genotypes observed in the present study, a considerable variability and the presence of few low-copy number strains have been described in earlier Brazilian studies (Fandinho et al 2000, Ferrazoli et al 2000, Suffys et al 2000, Telles et al 2005, Cafrune et al 2006. This is in concordance with genotype structure observed in most countries but in contrast with studies performed in the Middle East and Asia (Dale et al 1999, Narayanan et al 2002, Das et al 2005.…”

Section: Discussionsupporting

confidence: 92%

Typing of Mycobacterium tuberculosis strains isolated in Community Health Centers of Rio de Janeiro City, Brazil

Oelemann

Fontes

Pereira

et al. 2007

Mem. Inst. Oswaldo Cruz

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Fingerprinting of Mycobacterium tuberculosis strains from tuberculosis (TB) patients attended in Community Health Centers (CHCs) of Rio de Janeiro was performed to verify possible risk factors for TB transmission. A prospective community-based study was performed during the period of July 1996 to December 1996 by collecting sputum samples of 489 patients in 11 different CHCs in four different planning areas (APs) of the city. Bacteriological, clinical, and epidemiological information was collected and M. tuberculosis genotypes defined after restriction fragment length polymorphism (IS6110-RFLP) and double repetitive element (DRE) fingerprinting of RFLP-clustered cases. Risk factors for TB transmission were looked for using three levels of cluster stringency. Among 349 (71%) positive cultures obtained, IS6110-RFLP typing could be performed on strains from 153 different patients. When using identity of RFLP patterns as cluster definition, 49 (32%) of the strains belonged to a cluster and none of the clinical or epidemiologic characteristics was associated with higher clustering levels. However, higher clustering level was observed in the AP including the central region of the city when compared to others. This strongly suggests that more recent transmission occurs in that area and this may be related with higher incidence of TB and HIV in this region.Key words: tuberculosis -molecular epidemiology -IS6110-restriction fragment length polymorphism -double repetitive element It is generally accepted that one third of the world population is infected with Mycobacterium tuberculosis (Mtb), and the estimated mortality because of tuberculosis (TB) in 2004 was nearly 2 million, demonstrating that Mtb is among the most deadly human infectious agents. The majority (95%) of TB cases occur in developing countries, a scenario mainly responsible for negligence of the seriousness of the disease in richer countries. The latter however were obliged to reconsider the importance of the disease, due to the association between increased TB risk and HIV infection and the spreading of multi-drug resistant (MDR) strains all over the world (WHO 2006).In developed nations, epidemiologic investigations that incorporate genotyping of Mtb by restriction fragment length polymorphism (RFLP) have lead to novel information about the spread of Mtb in the community and during institutional outbreaks, to a better understanding of the transmission dynamics of TB and to the differentiation of (re)infection from reactivation (Barnes & Cave 2003, Seidler et al. 2004.Since the early nineties, definition of risk factors for TB transmission in high TB incidence areas has been complemented by information obtained by Mtb genotyping, the latter based on the recognition that clusters of fingerprints are a measure of recent transmission (Palittapongarnpim et al. 1997, Pineda-Garcia et al. 1997, Dale et al. 1999, Haas et al. 1999, Fandinho et al. 2000, Ferrazoli et al. 2000, Bruchfeld et al. 2002, Ferdinand et al. 2003, Easterbrook et al. 2004, Das et al. 2005. ...

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Section: Discussionsupporting

confidence: 92%

Typing of Mycobacterium tuberculosis strains isolated in Community Health Centers of Rio de Janeiro City, Brazil

Oelemann

Fontes

Pereira

et al. 2007

Mem. Inst. Oswaldo Cruz

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“…However, the applicability of this standardized system has so far not been tested in high TB-burden countries, except in a geographically restricted South African setting with extreme epidemiological conditions [17] or in certain Chinese regions with a specific M. tuberculosis Beijing strain population [18]. More specifically, only a few, limited molecular epidemiological studies have been performed in Brazil [19], [20], [21], [22], [23], [24].…”

Section: Introductionmentioning

confidence: 99%

The Forest behind the Tree: Phylogenetic Exploration of a Dominant Mycobacterium tuberculosis Strain Lineage from a High Tuberculosis Burden Country

et al. 2011

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BackgroundGenotyping of Mycobacterium tuberculosis isolates is a powerful tool for epidemiological control of tuberculosis (TB) and phylogenetic exploration of the pathogen. Standardized PCR-based typing, based on 15 to 24 mycobacterial interspersed repetitive unit-variable number of tandem repeat (MIRU-VNTR) loci combined with spoligotyping, has been shown to have adequate resolution power for tracing TB transmission and to be useful for predicting diverse strain lineages in European settings. Its informative value needs to be tested in high TB-burden countries, where the use of genotyping is often complicated by dominance of geographically specific, genetically homogeneous strain lineages.Methodology/Principal FindingsWe tested this genotyping system for molecular epidemiological analysis of 369 M. tuberculosis isolates from 3 regions of Brazil, a high TB-burden country. Deligotyping, targeting 43 large sequence polymorphisms (LSPs), and the MIRU-VNTRplus identification database were used to assess phylogenetic predictions. High congruence between the different typing results consistently revealed the countrywide supremacy of the Latin-American-Mediterranean (LAM) lineage, comprised of three main branches. In addition to an already known RDRio branch, at least one other branch characterized by a phylogenetically informative LAM3 spoligo-signature seems to be globally distributed beyond Brazil. Nevertheless, by distinguishing 321 genotypes in this strain population, combined MIRU-VNTR typing and spoligotyping demonstrated the presence of multiple distinct clones. The use of 15 to 24 loci discriminated 21 to 25% more strains within the LAM lineage, compared to a restricted lineage-specific locus set suggested to be used after SNP analysis. Noteworthy, 23 of the 28 molecular clusters identified were exclusively composed of patient isolates from a same region, consistent with expected patterns of mostly local TB transmission.Conclusions/SignificanceStandard MIRU-VNTR typing combined with spoligotyping can reveal epidemiologically meaningful clonal diversity behind a dominant M. tuberculosis strain lineage in a high TB-burden country and is useful to explore international phylogenetical ramifications.

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“…However, DNA fingerprinting studies performed in Brazil and especially in our state (RS), did not detect the presence of these strains. On the contrary, the great majority of strains presented high copy numbers of IS 6110 [32,33]…”

Section: Discussionmentioning

confidence: 99%

Comparison of two laboratory-developed PCR methods for the diagnosis of Pulmonary Tuberculosis in Brazilian patients with and without HIV infection

Scherer

Sperhacke

Jarczewski³

et al. 2011

BMC Pulm Med

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BackgroundDirect smear examination with Ziehl-Neelsen (ZN) staining for the diagnosis of pulmonary tuberculosis (PTB) is cheap and easy to use, but its low sensitivity is a major drawback, particularly in HIV seropositive patients. As such, new tools for laboratory diagnosis are urgently needed to improve the case detection rate, especially in regions with a high prevalence of TB and HIV.ObjectiveTo evaluate the performance of two in house PCR (Polymerase Chain Reaction): PCR dot-blot methodology (PCR dot-blot) and PCR agarose gel electrophoresis (PCR-AG) for the diagnosis of Pulmonary Tuberculosis (PTB) in HIV seropositive and HIV seronegative patients.MethodsA prospective study was conducted (from May 2003 to May 2004) in a TB/HIV reference hospital. Sputum specimens from 277 PTB suspects were tested by Acid Fast Bacilli (AFB) smear, Culture and in house PCR assays (PCR dot-blot and PCR-AG) and their performances evaluated. Positive cultures combined with the definition of clinical pulmonary TB were employed as the gold standard.ResultsThe overall prevalence of PTB was 46% (128/277); in HIV+, prevalence was 54.0% (40/74). The sensitivity and specificity of PCR dot-blot were 74% (CI 95%; 66.1%-81.2%) and 85% (CI 95%; 78.8%-90.3%); and of PCR-AG were 43% (CI 95%; 34.5%-51.6%) and 76% (CI 95%; 69.2%-82.8%), respectively. For HIV seropositive and HIV seronegative samples, sensitivities of PCR dot-blot (72% vs 75%; p = 0.46) and PCR-AG (42% vs 43%; p = 0.54) were similar. Among HIV seronegative patients and PTB suspects, ROC analysis presented the following values for the AFB smear (0.837), Culture (0.926), PCR dot-blot (0.801) and PCR-AG (0.599). In HIV seropositive patients, these area values were (0.713), (0.900), (0.789) and (0.595), respectively.ConclusionResults of this study demonstrate that the in house PCR dot blot may be an improvement for ruling out PTB diagnosis in PTB suspects assisted at hospitals with a high prevalence of TB/HIV.

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Recent transmission of tuberculosis involving retired patients

Cited by 7 publications

References 26 publications

Typing of Mycobacterium tuberculosis strains isolated in Community Health Centers of Rio de Janeiro City, Brazil

Typing of Mycobacterium tuberculosis strains isolated in Community Health Centers of Rio de Janeiro City, Brazil

The Forest behind the Tree: Phylogenetic Exploration of a Dominant Mycobacterium tuberculosis Strain Lineage from a High Tuberculosis Burden Country

Comparison of two laboratory-developed PCR methods for the diagnosis of Pulmonary Tuberculosis in Brazilian patients with and without HIV infection

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