Diagnostic accuracy of Xpert MTB/RIF Ultra and culture assays to detect Mycobacterium Tuberculosis using OMNIgene-sputum processed stool among adult TB presumptive patients in Uganda
Sessolo et al.
The finding, in our words
Processing stool samples with OMNIgene SPUTUM significantly improved the diagnostic yield of Mycobacterium tuberculosis using the Xpert MTB/RIF Ultra assay compared to standard methods, offering a viable alternative for patients who cannot produce sputum.
A paraphrase to the Library’s standard, never the abstract. The source is one link away and is always the authority.
TB-MBLA testing of OMNIgene-stabilised stool detected Mycobacterium tuberculosis with 80% sensitivity and 79% specificity against sputum culture in 100 adults, offering a viable alternative for patients unable to produce sputum. The RNA-based assay quantified bacterial load, showing higher burdens in HIV-co-infected individuals, while stool cultures suffered 21-26% contamination rates.
The paper identified that the Zymo DNA/RNA shield preservative paired with the QIAamp Viral RNA Mini Kit extraction yielded more detectable SARS-CoV-2 RNA from stool than the OMNIgene-GUT kit or storage without preservative. This supports decentralised diagnostics by establishing a validated method for preserving and analysing self-collected stool samples, enabling reliable detection of viral shedding for epidemiology and patient management.
A study limited by sample size found OMNIgene GUT tubes preserved Cryptosporidium DNA better than DNA Shield and FTA cards after year-long ambient storage. qPCR detected DNA in 23/24 OMNIgene, 21/24 DNA Shield, and 17/20 FTA samples, while metagenomics detected it in 13/24, 9/24, and 0/24 samples respectively, guiding decentralised sampling choices.
In a field cohort of 60 adults with diarrhoea, OMNIgene 200 and DNA/RNA shield maintained high sensitivity and concordance with fresh samples for most pathogens, while FTA cards showed low sensitivity for STEC and poor specificity for Campylobacter. This supports the use of stabilised stool media for decentralised PCR testing after prolonged ambient transport.
This study compared OMNIgene Gut tubes and FTA cards for stool collection in a deployed setting, finding that OMNIgene yielded higher nucleic acid concentrations while both methods detected the majority of microbial genera. The authors conclude that distinct microbial abundance profiles between the two methods necessitate standardised protocols for field research.