Investigation of OMNIgene·SPUTUM performance in delayed tuberculosis testing by smear, culture, and Xpert MTB/RIF assays in Uganda

C D Kelly-Cirino; E Musisi; P Byanyima; S Kaswabuli; A Andama; A Sessolo; I Sanyu; J Zawedde; P S Curry; L Huang

doi:10.1016/j.jegh.2017.04.001

Investigation of OMNIgene·SPUTUM performance in delayed tuberculosis testing by smear, culture, and Xpert MTB/RIF assays in Uganda

J Epidemiol Glob Health. 2017 Jun;7(2):103-109. doi: 10.1016/j.jegh.2017.04.001. Epub 2017 Apr 13.

Authors

C D Kelly-Cirino¹, E Musisi², P Byanyima³, S Kaswabuli⁴, A Andama⁵, A Sessolo⁶, I Sanyu⁷, J Zawedde⁸, P S Curry⁹, L Huang¹⁰

Affiliations

¹ DNA Genotek, 500 Palladium Dr., Suite 3000, Ottawa, Ontario K2V 1C2, Canada. Electronic address: [email protected].
² Infectious Diseases Research Collaboration Kampala, 2C Nakasero Hill Road, PO Box 7475, Kampala, Uganda. Electronic address: [email protected].
³ Infectious Diseases Research Collaboration Kampala, 2C Nakasero Hill Road, PO Box 7475, Kampala, Uganda. Electronic address: [email protected].
⁴ Infectious Diseases Research Collaboration Kampala, 2C Nakasero Hill Road, PO Box 7475, Kampala, Uganda. Electronic address: [email protected].
⁵ Infectious Diseases Research Collaboration Kampala, 2C Nakasero Hill Road, PO Box 7475, Kampala, Uganda. Electronic address: [email protected].
⁶ Infectious Diseases Research Collaboration Kampala, 2C Nakasero Hill Road, PO Box 7475, Kampala, Uganda. Electronic address: [email protected].
⁷ Infectious Diseases Research Collaboration Kampala, 2C Nakasero Hill Road, PO Box 7475, Kampala, Uganda. Electronic address: [email protected].
⁸ Infectious Diseases Research Collaboration Kampala, 2C Nakasero Hill Road, PO Box 7475, Kampala, Uganda. Electronic address: [email protected].
⁹ DNA Genotek, 500 Palladium Dr., Suite 3000, Ottawa, Ontario K2V 1C2, Canada. Electronic address: [email protected].
¹⁰ University of California San Francisco, HIV, Infectious Diseases, and Global Medicine Division and Division of Pulmonary and Critical Care Medicine - Ward 84, San Francisco General Hospital, 995 Potrero Avenue, San Francisco, CA 94110, USA. Electronic address: [email protected].

Abstract

OMNIgene·SPUTUM (OM-S) is a sample transport reagent designed to work with all tuberculosis diagnostics while eliminating the need for cold chain. OM-S-treated sputum samples were assayed in several tests after multiday holds. Raw sputa from 100 patients underwent direct smear microscopy, were manually split and assigned to the OM-S group [OM-S added at collection (no other processing required) and tested after 0- to 5-day holds at room temperature] or standard-of-care (SOC) group (NaOH/N-acetyl l-cysteine decontamination, all tested on day of collection). Concentrated smear microscopy, Lowenstein Jensen (LJ) culture, and mycobacteria growth indicator tube (MGIT) culture were performed. For patients with negative direct smear, a second sample was split, with SOC (raw sputum) and OM-S portions (sediment) tested in the Xpert MTB/RIF (Xpert) assay. OM-S group and SOC group results were strongly concordant on all four tests [range, 89% (MGIT)-97% (Xpert)]. OM-S MGIT, LJ, and Xpert tests were in statistical agreement with SOC MGIT as reference. OM-S specimens had lower culture contamination rates (3% vs. 10% LJ; 2% vs. 5% MGIT) but required, on average, 5.6 additional days to become MGIT-positive. The findings suggest that samples held/transported in OM-S are compatible with smear microscopy, LJ or MGIT culture, and Xpert, and perform comparably to fresh sputum samples. Larger feasibility studies are warranted.

Keywords: MGIT; Molecular detection; Mycobacterium tuberculosis; Preservation; Solid culture; Specimen transport medium.

MeSH terms

Humans
Microscopy
Molecular Diagnostic Techniques / methods*
Mycobacterium tuberculosis / isolation & purification*
Reproducibility of Results
Sensitivity and Specificity
Specimen Handling / methods*
Sputum / microbiology*
Time
Tuberculosis / diagnosis*
Uganda