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Diagnosis of smear-negative tuberculosis is greatly improved by Xpert MTB/RIF
BACKGROUND: Diagnosis of pulmonary (PTB) and extra-pulmonary tuberculosis (EPTB) in smear-negative patients can be difficult. We assessed retrospectively the performance of Xpert MTB/RIF system (Xpert, Cepheid) in diagnosing smear-negative tuberculosis (TB), which represents the most common form of...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5400262/ https://www.ncbi.nlm.nih.gov/pubmed/28430807 http://dx.doi.org/10.1371/journal.pone.0176186 |
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author | Lombardi, Giulia Di Gregori, Valentina Girometti, Nicolò Tadolini, Marina Bisognin, Francesco Dal Monte, Paola |
author_facet | Lombardi, Giulia Di Gregori, Valentina Girometti, Nicolò Tadolini, Marina Bisognin, Francesco Dal Monte, Paola |
author_sort | Lombardi, Giulia |
collection | PubMed |
description | BACKGROUND: Diagnosis of pulmonary (PTB) and extra-pulmonary tuberculosis (EPTB) in smear-negative patients can be difficult. We assessed retrospectively the performance of Xpert MTB/RIF system (Xpert, Cepheid) in diagnosing smear-negative tuberculosis (TB), which represents the most common form of TB in a low incidence setting. METHODS: Performance of Xpert was compared to acid-fast microscopic examination using Ziehl-Neelsen (ZN) stain in patients with culture-confirmed TB. RESULTS: 386 Mycobacterium tuberculosis (MTB) culture-positive samples were detected out of 5170 specimens tested with smear microscopy, Xpert and culture: 323 were both culture- and Xpert-positive, and 63 culture-positive only. Of these, 234 (60.6%) were smear-negative. In addition Xpert detected 40 probable TB cases, based on clinical findings, which were culture-negative. Compared to culture, Xpert showed an overall sensitivity of 83.7% and a specificity of 99.1%; sensitivity was higher for respiratory samples (86.5%) than for non-respiratory samples (76.8%). Xpert sensitivity for smear-negative culture-confirmed TB was 73.1% and was not influenced by TB localization. As sensitivity of microscopy alone was poor (39.4%), Xpert improved both diagnosis of pulmonary TB (Δ = 36.5%) and extra-pulmonary TB (Δ = 63.4%). CONCLUSIONS: Xpert MTB/RIF is a sensitive method for rapid diagnosis of TB compared to the conventional ZN staining. Xpert can serve as a sensitive and time-saving diagnostic method for microbiological diagnosis of smear-negative TB in countries with a low TB prevalence. |
format | Online Article Text |
id | pubmed-5400262 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-54002622017-05-12 Diagnosis of smear-negative tuberculosis is greatly improved by Xpert MTB/RIF Lombardi, Giulia Di Gregori, Valentina Girometti, Nicolò Tadolini, Marina Bisognin, Francesco Dal Monte, Paola PLoS One Research Article BACKGROUND: Diagnosis of pulmonary (PTB) and extra-pulmonary tuberculosis (EPTB) in smear-negative patients can be difficult. We assessed retrospectively the performance of Xpert MTB/RIF system (Xpert, Cepheid) in diagnosing smear-negative tuberculosis (TB), which represents the most common form of TB in a low incidence setting. METHODS: Performance of Xpert was compared to acid-fast microscopic examination using Ziehl-Neelsen (ZN) stain in patients with culture-confirmed TB. RESULTS: 386 Mycobacterium tuberculosis (MTB) culture-positive samples were detected out of 5170 specimens tested with smear microscopy, Xpert and culture: 323 were both culture- and Xpert-positive, and 63 culture-positive only. Of these, 234 (60.6%) were smear-negative. In addition Xpert detected 40 probable TB cases, based on clinical findings, which were culture-negative. Compared to culture, Xpert showed an overall sensitivity of 83.7% and a specificity of 99.1%; sensitivity was higher for respiratory samples (86.5%) than for non-respiratory samples (76.8%). Xpert sensitivity for smear-negative culture-confirmed TB was 73.1% and was not influenced by TB localization. As sensitivity of microscopy alone was poor (39.4%), Xpert improved both diagnosis of pulmonary TB (Δ = 36.5%) and extra-pulmonary TB (Δ = 63.4%). CONCLUSIONS: Xpert MTB/RIF is a sensitive method for rapid diagnosis of TB compared to the conventional ZN staining. Xpert can serve as a sensitive and time-saving diagnostic method for microbiological diagnosis of smear-negative TB in countries with a low TB prevalence. Public Library of Science 2017-04-21 /pmc/articles/PMC5400262/ /pubmed/28430807 http://dx.doi.org/10.1371/journal.pone.0176186 Text en © 2017 Lombardi et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
spellingShingle | Research Article Lombardi, Giulia Di Gregori, Valentina Girometti, Nicolò Tadolini, Marina Bisognin, Francesco Dal Monte, Paola Diagnosis of smear-negative tuberculosis is greatly improved by Xpert MTB/RIF |
title | Diagnosis of smear-negative tuberculosis is greatly improved by Xpert MTB/RIF |
title_full | Diagnosis of smear-negative tuberculosis is greatly improved by Xpert MTB/RIF |
title_fullStr | Diagnosis of smear-negative tuberculosis is greatly improved by Xpert MTB/RIF |
title_full_unstemmed | Diagnosis of smear-negative tuberculosis is greatly improved by Xpert MTB/RIF |
title_short | Diagnosis of smear-negative tuberculosis is greatly improved by Xpert MTB/RIF |
title_sort | diagnosis of smear-negative tuberculosis is greatly improved by xpert mtb/rif |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5400262/ https://www.ncbi.nlm.nih.gov/pubmed/28430807 http://dx.doi.org/10.1371/journal.pone.0176186 |
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