Features | Partner Sites | Information | LinkXpress
Sign In
GLOBETECH MEDIA
GLOBETECH PUBLISHING LLC
GLOBETECH PUBLISHING LLC

Rapid, Automated Test Accurately Detects Tuberculosis in Pediatric Samples

By BiotechDaily International staff writers
Posted on 08 Aug 2013
Image: The Xpert MTB/RIF test cartridge (Photo courtesy of Cepheid).
Image: The Xpert MTB/RIF test cartridge (Photo courtesy of Cepheid).
Image: The GeneXpert System loaded with a test cartridge (Photo courtesy of Cepheid).
Image: The GeneXpert System loaded with a test cartridge (Photo courtesy of Cepheid).
A team of South African investigators compared the effectiveness of a new, automated diagnostic test that simultaneously detects tuberculosis (TB) and rifampicin resistance to classical microscopy and culture methods in pediatric samples.

The World Health Organization (WHO) estimated that in 2011 alone more than 500,000 new cases of TB appeared with nearly 64,000 deaths among those younger than 15 years of age.

The authors of the current study collected nearly 1,500 paired sputum and nasopharyngeal specimens from 354 children who presented at a primary care clinic with symptoms of TB. The samples were analyzed with the Cepheid (Sunnyvale, CA, USA; www.cepheidinternational.com) Xpert MTB/RIF test, and the diagnostic accuracy of the results were compared with the reference standards of culture and smear microscopy.

The Xpert MTB/RIF Test detects both TB and rifampicin resistance high sensitivity even in smear negative, culture positive specimens. The test produces results in two hours and requires no instrumentation other than the GeneXpert System.

Cepheid's GeneXpert System is a closed, self-contained, fully integrated, and automated platform that combines on-board sample preparation with real-time PCR (polymerase chain reaction) amplification and detection functions for fully integrated and automated nucleic acid analysis. The system is designed to purify, concentrate, detect, and identify targeted nucleic acid sequences thereby delivering answers directly from unprocessed samples.

Results revealed that five children (1%) tested positive for tuberculosis by smear microscopy, 26 (7%) tested positive by Xpert MTB/RIF, and 30 (8%) tested positive by culture. Among children who did not in fact have the disease, the results of the Xpert test reported negative for TB with 99% accuracy. These findings suggest that Xpert MTB/RIF on respiratory secretions is a useful test for rapid diagnosis of pediatric pulmonary tuberculosis in primary care.

Dr. Fred Tenover, senior director of scientific affairs at Cepheid, said, "If you were to inoculate an Xpert MTB/RIF test at the same time you started preparing your acid fast smears, by the time you finished reading the smears, the Xpert MTB/RIF test result would be ready, telling you if your positive acid fast smear was TB and if the strain was resistant to rifampicin, which is an excellent surrogate marker for MDR (multiple drug resistant)-TB. I am sure Koch and Pasteur would not only be delighted with the technological advance, they would probably say, 'It is about time.'"

“There has been a perception amongst health care workers that rapid diagnosis of TB in children would not be possible in primary care, but this study disproves that view, said first author Dr. Heather Zar, professor of pediatrics at the University of Cape Town (South Africa; www.scah.uct.ac.za). “Given our results, widespread adoption of rapid testing for TB and drug resistance in children may substantially improve public health without greatly increasing costs.”

Results of the South African study were published in the August 2013 issue of the journal the Lancet Global Health.

Related Links:

Cepheid

University of Cape Town



Channels

Genomics/Proteomics

view channel
Image: An adult cardiomyocyte has re-entered the cell cycle after expression of miR302-367 (Photo courtesy of the laboratory of Dr. Edward Morrisey, University of Pennsylvania).

Certain MicroRNAs Stimulate Regeneration of Adult Heart Tissue

Cardiac disease researchers working with a mouse model have discovered that by inducing a subset of microRNAs (miRNAs) that are active during development but silenced in the adult they could cause damaged... Read more

Drug Discovery

view channel
Image: Wafers like the one shown here are used to create “organ-on-a-chip” devices to model human tissue (Photo courtesy of Dr. Anurag Mathur, University of California, Berkeley).

Human Heart-on-a-Chip Cultures May Replace Animal Models for Drug Development and Safety Screening

Human heart cells growing in an easily monitored silicon chip culture system may one day replace animal-based model systems for drug development and safety screening. Drug discovery and development... Read more

Biochemistry

view channel
Image:  Model depiction of a novel cellular mechanism by which regulation of cryptochromes Cry1 and Cry2 enables coordination of a protective transcriptional response to DNA damage caused by genotoxic stress (Photo courtesy of the journal eLife, March 2015, Papp SJ, Huber AL, et al.).

Two Proteins Critical for Circadian Cycles Protect Cells from Mutations

Scientists have discovered that two proteins critical for maintaining healthy day-night cycles also have an unexpected role in DNA repair and protecting cells against genetic mutations that could lead... Read more

Business

view channel

“Softer” Mass Spec Techniques Gain Advantage in Biomarker Discovery

Two mass spectrometry (MS) technologies, MALDI and DESI, are increasing in applications as their effectiveness is established, according to Kalorama Information (New York, NY, USA) in its report “Proteomics Markets for Research and IVD Applications (Mass Spectrometry, Chromatography, Microarrays, Electrophoresis, Immunoassays,... Read more
 
Copyright © 2000-2015 Globetech Media. All rights reserved.