Abstract:
SETTING : Mopani District, South Africa.
OBJECTIVE : To explore remote, molecular detection of
Mycobacterium tuberculosis from sputum transported
using PrimeStorew Molecular Transport Medium (PSMTM)
compared to settings where microscopy or
Xpertw MTB/RIF is used as the baseline test.
DESIGN : Two sputum specimens were collected from
patients with cough of72 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
PrimeMixw polymerase chain reaction (PM-PCR).
RESULTS : Of 132 patients, 23 (17%) were positive on
microscopy, 39 (30%) on Xpert and 44 (33%) by PSMTM/PSMTM/
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 ¼ 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.
