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283183

A Study of the Added Value of Xpert MTB/RIF Assay for Assessment of Pulmonary Tuberculosis Transmission Risk

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Last updated: 28 Dec 2024

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Abstract

Background: The elimination of TB requires early, rapid and accurate diagnosis and treatment. TB mortality is mainly due to delayed diagnosis or misdiagnosis which also increases the possibility of TB transmission. Xpert MTB/RIF assay is a new rapid point- of-care test that can in 2 hours, simultaneously detect, Mycobacterium tuberculosis and rifampicin resistance and is capable of overcoming many of the current operational problems in TB diagnosis. Objective: to evaluate the usefulness of Xpert MTB/RIF test for early, rapid, and accurate diagnosis of pulmonary tuberculosis and to determine the added value of the assay to address patients' transmission potential in a fast, accurate and reliable manner. Methodology: Spot sputum samples collected at hospital presentation from fifty patients with symptoms and signs suggestive of pulmonary TB and / or who have suggestive TB chest x-ray, during the period from August 2017 to July 2018. All microbiological analyses were performed on the same sample after splitting it into two aliquots. One aliquot was tested by ZN staining and Xpert MTB/RIF assay and the other was cultured for isolation of TB bacilli by conventional method. Diagnostic performance was done for both ZN stained smear and XPERT MTB/RIF assay using culture as a reference standard. Results: Compared with culture, the sensitivity and the specificity of XPERT MTB/RIF assay were 100% and 75% respectively, PPV was 95.5%, NPV was 100% and there was very good (kappa = 0.834) agreement between both methods. Two samples tested positive by XPERT MTB/RIF though negative by culture and there was significant negative correlation between semi-quantitative results of XPERT MTB/RIF test expressed in cycle threshold values against grade of smear positivity. Conclusion: Xpert MTB/RIF assay had a very high sensitivity and specificity when compared to the reference standard method. It is a single test that is more effective than smear dependent strategies for both T.B diagnosis and evaluation of patient transmission potential. It can detect M. tuberculosis complex and rifampicin resistance in two hours. The assay is rapid, easy to perform with no technical difficulties. This new diagnostic method can lead to more cases of active TB to be detected, avoiding treatment delay, reduction in the transmission risk and improvement in TB control.

DOI

10.21608/ejmm.2019.283183

Keywords

Xpert MTB/RIF test, pulmonary tuberculosis - transmission potential

Authors

First Name

Mona

Last Name

Fouda

MiddleName

E.

Affiliation

Department of Clinical and Chemical Pathology, Faculty of Medicine, Benha University

Email

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City

-

Orcid

-

First Name

Eman

Last Name

Abdel Gwad

MiddleName

R.

Affiliation

Department of Clinical and Chemical Pathology, Faculty of Medicine, Benha University

Email

-

City

-

Orcid

-

First Name

sahar

Last Name

fayed

MiddleName

mohamad

Affiliation

Department of Clinical and Chemical Pathology, Faculty of Medicine, Benha University

Email

saharmohamadfayed@gmail.com

City

egypt

Orcid

-

First Name

Mohammad

Last Name

Kamel

MiddleName

H.

Affiliation

Department of Chest Diseases, Faculty of Medicine, Benha University, Egypt

Email

-

City

-

Orcid

-

First Name

Sanaa

Last Name

Ahmed

MiddleName

A.

Affiliation

Department of Clinical Pathology Resident, Benha Chest Hospital, Qaliobia Directorate of Health

Email

-

City

-

Orcid

-

Volume

28

Article Issue

3

Related Issue

39243

Issue Date

2019-07-01

Receive Date

2023-01-30

Publish Date

2019-07-01

Page Start

141

Page End

148

Print ISSN

1110-2179

Online ISSN

2537-0979

Link

https://ejmm.journals.ekb.eg/article_283183.html

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https://ejmm.journals.ekb.eg/service?article_code=283183

Order

283,183

Type

New and original researches in the field of Microbiology.

Type Code

2,038

Publication Type

Journal

Publication Title

Egyptian Journal of Medical Microbiology

Publication Link

https://ejmm.journals.ekb.eg/

MainTitle

A Study of the Added Value of Xpert MTB/RIF Assay for Assessment of Pulmonary Tuberculosis Transmission Risk

Details

Type

Article

Created At

28 Dec 2024