L T Daum1, R P H Peters2, P B Fourie3, K Jonkman4, S A Worthy1, J D Rodriguez1, N A Ismail5, S V Omar5, G W Fischer1. 1. Longhorn Vaccines & Diagnostics, San Antonio, Texas, USA. 2. Anova Health Institute, Johannesburg, South Africa; Department of Medical Microbiology, University of Pretoria, South Africa; Department of Medical Microbiology, Maastricht University Medical Centre, Maastricht, The Netherlands. 3. Department of Medical Microbiology, University of Pretoria, South Africa. 4. Anova Health Institute, Johannesburg, South Africa. 5. National Institute for Communicable Diseases, National TB Reference Laboratory, Sandringham, South Africa.
Abstract
SETTING: Mopani District, South Africa. OBJECTIVE: To explore remote, molecular detection of Mycobacterium tuberculosis from sputum transported using PrimeStore(®) Molecular Transport Medium (PS-MTM) compared to settings where microscopy or Xpert(®) MTB/RIF is used as the baseline test. DESIGN: Two sputum specimens were collected from patients with cough of ⩾ 2 weeks at clinics in rural South Africa. Shortly after expectoration and before processing using Xpert, microscopy and liquid culture, a flocked swab was swirled in each of these specimens and placed in PS-MTM. Swabs were stored and transported to the United States at ambient temperature for real-time PrimeMix(®) polymerase chain reaction (PM-PCR). RESULTS: Of 132 patients, 23 (17%) were positive on microscopy, 39 (30%) on Xpert and 44 (33%) by PS-MTM/PM-PCR. Concordance of PS-MTM/PM-PCR with positive microscopy and Xpert was respectively 96% and 85%. Of 107 microscopy-negative samples, 22 (21%) were positive using PS-MTM/PM-PCR, while 11/91 (12%) Xpert-negative samples were PS-MTM/PM-PCR-positive. PS-MTM/PM-PCR positivity was significantly higher than smear microscopy positivity (P < 0.001), but similar to Xpert (P = 0.33). CONCLUSION: PCR testing of specimens transported in PS-MTM would enhance TB diagnosis in settings where smear microscopy is the baseline diagnostic test, and could provide an alternative in settings where Xpert testing is not available.
SETTING: Mopani District, South Africa. OBJECTIVE: To explore remote, molecular detection of Mycobacterium tuberculosis from sputum transported using PrimeStore(®) Molecular Transport Medium (PS-MTM) compared to settings where microscopy or Xpert(®) MTB/RIF is used as the baseline test. DESIGN: Two sputum specimens were collected from patients with cough of ⩾ 2 weeks at clinics in rural South Africa. Shortly after expectoration and before processing using Xpert, microscopy and liquid culture, a flocked swab was swirled in each of these specimens and placed in PS-MTM. Swabs were stored and transported to the United States at ambient temperature for real-time PrimeMix(®) polymerase chain reaction (PM-PCR). RESULTS: Of 132 patients, 23 (17%) were positive on microscopy, 39 (30%) on Xpert and 44 (33%) by PS-MTM/PM-PCR. Concordance of PS-MTM/PM-PCR with positive microscopy and Xpert was respectively 96% and 85%. Of 107 microscopy-negative samples, 22 (21%) were positive using PS-MTM/PM-PCR, while 11/91 (12%) Xpert-negative samples were PS-MTM/PM-PCR-positive. PS-MTM/PM-PCR positivity was significantly higher than smear microscopy positivity (P < 0.001), but similar to Xpert (P = 0.33). CONCLUSION: PCR testing of specimens transported in PS-MTM would enhance TB diagnosis in settings where smear microscopy is the baseline diagnostic test, and could provide an alternative in settings where Xpert testing is not available.
Authors: David J Horne; Mikashmi Kohli; Jerry S Zifodya; Ian Schiller; Nandini Dendukuri; Deanna Tollefson; Samuel G Schumacher; Eleanor A Ochodo; Madhukar Pai; Karen R Steingart Journal: Cochrane Database Syst Rev Date: 2019-06-07