Evaluation of the fluorescent-thin layer chromatography (f-TLC) for the diagnosis of Buruli ulcer disease in Ghana
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Date
2022
Journal Title
Journal ISSN
Volume Title
Publisher
PLOS ONE
Abstract
Abstract
Background
Buruli ulcer is a tissue necrosis infection caused by an environmental mycobacterium called
Mycobacterium ulcerans (MU). The disease is most prevalent in rural areas with the highest
rates in West and Central African countries. The bacterium produces a toxin called mycolactone
which can lead to the destruction of the skin, resulting in incapacitating deformities with
an enormous economic and social burden on patients and their caregivers. Even though
there is an effective antibiotic treatment for BU, the control and management rely on early
case detection and rapid diagnosis to avert morbidities. The diagnosis of Mycobacterium
ulcerans relies on smear microscopy, culture histopathology, and PCR. Unfortunately, all
the current laboratory diagnostics have various limitations and are not available in endemic
communities. Consequently, there is a need for a rapid diagnostic tool for use at the community
health centre level to enable diagnosis and confirmation of suspected cases for early
treatment. The present study corroborated the diagnostic performance and utility of fluorescent-
thin layer chromatography (f-TLC) for the diagnosis of Buruli ulcer.
Methodology/Principal findings
The f-TLC method was evaluated for the diagnosis of Buruli ulcer in larger clinical samples
than previously reported in an earlier preliminary study Wadagni et al. (2015). A total of 449
patients suspected of BU were included in the final data analysis out of which 122 (27.2%)
were positive by f-TLC and 128 (28.5%) by PCR. Using a composite reference method generated
from the two diagnostic methods, 85 (18.9%) patients were found to be truly infected
with M. ulcerans, 284 (63.3%) were uninfected, while 80 (17.8%) were misidentified as
infected or noninfected by the two methods. The data obtained was used to determine the
discriminatory accuracy of the f-TLC against the gold standard IS2404 PCR through the
analysis of its sensitivity, specificity, positive (+LR), and negative (–LR) likelihood ratio. The
positive (PPV) and negative (NPV) predictive values, area under the receiver operating
characteristic curve Azevedo et al. (2014), and diagnostic odds ratio were used to assessthe predictive accuracy of the f-TLC method. The sensitivity of f-TLC was 66.4% (85/128),
specificity was 88.5% (284/321), while the diagnostic accuracy was 82.2% (369/449). The
AUC stood at 0.774 while the PPV, NPV, +LR, and–LR were 69.7% (85/122), 86.9% (284/
327), 5.76, and 0.38, respectively. The use of the rule-of-thumb interpretation of diagnostic
tests suggests that the method is good for use as a diagnostic tool.
Conclusions/Significance
Larger clinical samples than previously reported had been used to evaluate the f-TLC
method for the diagnosis of Buruli ulcer. A sensitivity of 66.4%, a specificity of 88.5%, and
diagnostic accuracy of 82.2% were obtained. The method is good for diagnosis and will help
in making early clinical decisions about the patients as well as patient management and
facilitating treatment decisions. However, it requires a slight modification to address the
challenge of background interference and lack of automatic readout to become an excellent
diagnostic tool.
Introduction
Description
Research Article
Keywords
Evaluation of the fluorescent-thin layer, Buruli ulcer disease, disease, Ghana
Citation
https://doi.org/10.1371/journal.pone.0270235