Lung Pathogens Detected Faster by Molecular-Based Method
|
By LabMedica International staff writers Posted on 07 Jul 2016 |
|
Image: A photomicrograph of auramine-rhodamine stained Mycobacterium tuberculosis (Photo courtesy of Dr. T.V. Rao, MD).
The genus Mycobacterium is separated into the pathogenic species Mycobacterium tuberculosis complex (MTB), Mycobacterium leprae, and Mycobacterium ulcerans, and various nontuberculous mycobacteria (NTM).
New molecular-based methods are being developed to detect mycobacterial pathogens that cause pulmonary infections or tuberculosis faster than before. Time-consuming bacteria cultures no longer need to be taken from the patient samples, meaning that a suitable therapy can be started quickly.
Scientists at the University of Zurich (Switzerland) used a large-scale study with more than 6,800 patient samples to examine molecular-based methods for the detection of mycobacterial pathogens. Because many mycobacteria only grow at a very slow pace, routine detection using bacteria cultures in highly specialized and expensive high-safety laboratories takes several weeks to complete. The subsequent susceptibility test to determine the appropriate medicine also takes one to two weeks.
All samples were analyzed in parallel using culture-based procedures and a modified COBAS TaqMan MTB test (Roche, Basel, Switzerland) for direct detection of MTB and NTM.MTB polymerase chain reaction (PCR) positive specimens were screened for mutations associated with resistance to isoniazid (INH) and rifampicin (RIF) using the AID TB resistance line probe assay module 1 (AID Diagnostika GmbH, Strassberg, Germany). Positive auramine-rhodamine microscopy results were confirmed by Ziehl-Neelsen staining.
MTB molecular-based detection and culture gave concordant results for 97.7% of the specimens. NTM PCR-based detection and culture gave concordant results for 97.0% of the specimens. Defining specimens on the basis of combined laboratory data as true positives or negatives with discrepant results resolved by clinical chart reviews, the scientists calculated sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for PCR-based MTB detection as 84.7%, 100%, 100%, and 98.7%. The corresponding values for culture-based MTB detection were 86.3%, 100%, 100%, and 98.8%. PCR-based detection of NTM had a sensitivity of 84.7% compared to 78.0% of that of culture-based NTM detection. Molecular drug susceptibility testing (DST) by line-probe assay was found to predict phenotypic DST results in MTB with excellent accuracy.
Peter M. Keller, MD, a senior author of the study said, “For patients and doctors, this long waiting period is an unnecessary test of their patience. By comparison, with molecular detection methods, most patients know after one or two days whether they have an infection with tuberculosis pathogens or with nontuberculous mycobacteria.” The study was published on June 16, 2016, in the journal EbioMedicine.
Related Links:
University of Zurich
Roche
AID Diagnostika
New molecular-based methods are being developed to detect mycobacterial pathogens that cause pulmonary infections or tuberculosis faster than before. Time-consuming bacteria cultures no longer need to be taken from the patient samples, meaning that a suitable therapy can be started quickly.
Scientists at the University of Zurich (Switzerland) used a large-scale study with more than 6,800 patient samples to examine molecular-based methods for the detection of mycobacterial pathogens. Because many mycobacteria only grow at a very slow pace, routine detection using bacteria cultures in highly specialized and expensive high-safety laboratories takes several weeks to complete. The subsequent susceptibility test to determine the appropriate medicine also takes one to two weeks.
All samples were analyzed in parallel using culture-based procedures and a modified COBAS TaqMan MTB test (Roche, Basel, Switzerland) for direct detection of MTB and NTM.MTB polymerase chain reaction (PCR) positive specimens were screened for mutations associated with resistance to isoniazid (INH) and rifampicin (RIF) using the AID TB resistance line probe assay module 1 (AID Diagnostika GmbH, Strassberg, Germany). Positive auramine-rhodamine microscopy results were confirmed by Ziehl-Neelsen staining.
MTB molecular-based detection and culture gave concordant results for 97.7% of the specimens. NTM PCR-based detection and culture gave concordant results for 97.0% of the specimens. Defining specimens on the basis of combined laboratory data as true positives or negatives with discrepant results resolved by clinical chart reviews, the scientists calculated sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for PCR-based MTB detection as 84.7%, 100%, 100%, and 98.7%. The corresponding values for culture-based MTB detection were 86.3%, 100%, 100%, and 98.8%. PCR-based detection of NTM had a sensitivity of 84.7% compared to 78.0% of that of culture-based NTM detection. Molecular drug susceptibility testing (DST) by line-probe assay was found to predict phenotypic DST results in MTB with excellent accuracy.
Peter M. Keller, MD, a senior author of the study said, “For patients and doctors, this long waiting period is an unnecessary test of their patience. By comparison, with molecular detection methods, most patients know after one or two days whether they have an infection with tuberculosis pathogens or with nontuberculous mycobacteria.” The study was published on June 16, 2016, in the journal EbioMedicine.
Related Links:
University of Zurich
Roche
AID Diagnostika
Gold Member
Fully Automated Cell Density/Viability Analyzer
BioProfile FAST CDV
New
HIV-1 Test
HIV-1 Real Time RT-PCR Kit
New
Silver Member
ACTH Assay
ACTH ELISA
Latest Microbiology News
- Handheld Device Deliver Low-Cost TB Results in Less Than One Hour
- New AI-Based Method Improves Diagnosis of Drug-Resistant Infections
- Breakthrough Diagnostic Technology Identifies Bacterial Infections with Almost 100% Accuracy within Three Hours
- Innovative ID/AST System to Help Diagnose Infectious Diseases and Combat AMR
- Gastrointestinal Panel Delivers Rapid Detection of Five Common Bacterial Pathogens for Outpatient Use
- Rapid PCR Testing in ICU Improves Antibiotic Stewardship
- Unique Genetic Signature Predicts Drug Resistance in Bacteria
- Unique Barcoding System Tracks Pneumonia-Causing Bacteria as They Infect Blood Stream
- Rapid Sepsis Diagnostic Test Demonstrates Improved Patient Care and Cost Savings in Hospital Application
- Rapid Diagnostic System to Detect Neonatal Sepsis Within Hours
- Novel Test to Diagnose Bacterial Pneumonia Directly from Whole Blood
- Interferon-γ Release Assay Effective in Patients with COPD Complicated with Pulmonary Tuberculosis
- New Point of Care Tests to Help Reduce Overuse of Antibiotics
- 30-Minute Sepsis Test Differentiates Bacterial Infections, Viral Infections, and Noninfectious Disease
- CRISPR-TB Blood Test to Enable Early Disease Diagnosis and Public Screening
- Syndromic Panel Provides Fast Answers for Outpatient Diagnosis of Gastrointestinal Conditions
Channels
Clinical Chemistry
view channel
Carbon Nanotubes Help Build Highly Accurate Sensors for Continuous Health Monitoring
Current sensors can measure various health indicators, such as blood glucose levels, in the body. However, there is a need to develop more accurate and sensitive sensor materials that can detect lower... Read more
Paper-Based Device Boosts HIV Test Accuracy from Dried Blood Samples
In regions where access to clinics for routine blood tests presents financial and logistical obstacles, HIV patients are increasingly able to collect and send a drop of blood using paper-based devices... Read more
Molecular Diagnostics
view channel
RNA-Based Blood Test Detects Preeclampsia Risk Months Before Symptoms
Preeclampsia remains a major cause of maternal morbidity and mortality, as well as preterm births. Despite current guidelines that aim to identify pregnant women at increased risk of preeclampsia using... Read more
First Of Its Kind Test Uses microRNAs to Predict Toxicity from Cancer Therapy
Many men with early-stage prostate cancer receive stereotactic body radiotherapy (SBRT), a highly precise form of radiation treatment that is completed in just five sessions. Compared to traditional radiation,... Read more
Novel Cell-Based Assay Provides Sensitive and Specific Autoantibody Detection in Demyelination
Anti-myelin-associated glycoprotein (MAG) antibodies serve as markers for an autoimmune demyelinating disorder that affects the peripheral nervous system, leading to sensory impairment. Anti-MAG-IgM antibodies... Read more
Hematology
view channel
New Scoring System Predicts Risk of Developing Cancer from Common Blood Disorder
Clonal cytopenia of undetermined significance (CCUS) is a blood disorder commonly found in older adults, characterized by mutations in blood cells and a low blood count, but without any obvious cause or... Read more
Non-Invasive Prenatal Test for Fetal RhD Status Demonstrates 100% Accuracy
In the United States, approximately 15% of pregnant individuals are RhD-negative. However, in about 40% of these cases, the fetus is also RhD-negative, making the administration of RhoGAM unnecessary.... Read more
Immunology
view channel
Stem Cell Test Predicts Treatment Outcome for Patients with Platinum-Resistant Ovarian Cancer
Epithelial ovarian cancer frequently responds to chemotherapy initially, but eventually, the tumor develops resistance to the therapy, leading to regrowth. This resistance is partially due to the activation... Read more
Machine Learning-Enabled Blood Test Predicts Immunotherapy Response in Lymphoma Patients
Chimeric antigen receptor (CAR) T-cell therapy has emerged as one of the most promising recent developments in the treatment of blood cancers. However, over half of non-Hodgkin lymphoma (NHL) patients... Read more
Pathology
view channel
Advanced Imaging Reveals Mechanisms Causing Autoimmune Disease
Myasthenia gravis, an autoimmune disease, leads to muscle weakness that can affect a range of muscles, including those needed for basic actions like blinking, smiling, or moving. Researchers have long... Read more
AI Model Effectively Predicts Patient Outcomes in Common Lung Cancer Type
Lung adenocarcinoma, the most common form of non-small cell lung cancer (NSCLC), typically adopts one of six distinct growth patterns, often combining multiple patterns within a single tumor.... Read more
Technology
view channel
Pain-On-A-Chip Microfluidic Device Determines Types of Chronic Pain from Blood Samples
Chronic pain is a widespread condition that remains difficult to manage, and existing clinical methods for its treatment rely largely on self-reporting, which can be subjective and especially problematic... Read more
Innovative, Label-Free Ratiometric Fluorosensor Enables More Sensitive Viral RNA Detection
Viruses present a major global health risk, as demonstrated by recent pandemics, making early detection and identification essential for preventing new outbreaks. While traditional detection methods are... Read more
Industry
view channel
Cepheid and Oxford Nanopore Technologies Partner on Advancing Automated Sequencing-Based Solutions
Cepheid (Sunnyvale, CA, USA), a leading molecular diagnostics company, and Oxford Nanopore Technologies (Oxford, UK), the company behind a new generation of sequencing-based molecular analysis technologies,... Read more
Grifols and Tecan’s IBL Collaborate on Advanced Biomarker Panels
Grifols (Barcelona, Spain), one of the world’s leading producers of plasma-derived medicines and innovative diagnostic solutions, is expanding its offer in clinical diagnostics through a strategic partnership... Read more
