This study established evidence about the diagnostic
performance of trained giant African pouched rats for detecting Mycobacterium tuberculosis in
sputum of well-characterised patients with presumptive tuberculosis (TB) in a high-burden
setting.
The TB detection rats were evaluated using sputum samples of
patients with presumptive TB enrolled in two prospective cohort studies in
Bagamoyo, Tanzania. The patients were characterised by sputum smear microscopy
and culture, including subsequent antigen or molecular confirmation of Mycobacterium tuberculosis, and
by clinical data at enrolment and for at least 5-months of follow-up to
determine the reference standard. Seven trained giant African pouched rats were
used for the detection of TB in the sputum samples after shipment to the APOPO
project in Morogoro, Tanzania.
Of 469 eligible patients, 109 (23.2%) were culture-positive
for Mycobacterium
tuberculosis and 128
(27.3%) were non-TB controls with sustained recovery after 5 months without
anti-TB treatment. The HIV prevalence was 46%. The area under the receiver
operating characteristic curve of the seven rats for the detection of
culture-positive pulmonary tuberculosis was 0.72. An optimal
threshold could be defined at ≥2 indications by rats in either sample with a
corresponding sensitivity of 56.9%, specificity of 80.5%, positive and negative predictive value of 71.3% and 68.7%, and an accuracy for TB diagnosis of
69.6%. The diagnostic performance was negatively influenced by low burden of
bacilli, and independent of the HIV status.
Giant African pouched rats have potential for detection of
tuberculosis in sputum samples. However, the diagnostic performance
characteristics of TB detection rats do not currently meet the requirements for
high-priority, rapid sputum-based TB diagnostics as defined by the World Health
Organization.
Below: ROC analysis for the detection of M.tb culture-positive individuals for different indication thresholds (per-patient analysis; all samples)
Full article
at:
By:
Klaus Reither, Levan Jugheli, Tracy R. Glass
Swiss Tropical and Public Health Institute, Basel, Switzerland
More at: https://twitter.com/hiv_insight
No comments:
Post a Comment