Evaluation of the fluorescent-thin layer chromatography (f-TLC) for the diagnosis of Buruli ulcer disease in Ghana

• Published in: PloS one 2022-08, Vol.17 (8), p.e0270235-e0270235
• Main Authors: Amewu, Richard K, Akolgo, Gideon Atinga, Asare, Millicent Esi, Abdulai, Zigli, Ablordey, Anthony S, Asiedu, Kingsley
• Format: Article
• Language: English
• Subjects: Aluminum; Antibiotics; Bacteria; Biology and Life Sciences; Buruli ulcer; Chromatography; Data analysis; Decisions; Diagnosis; Diagnostic tests; Ethanol; Ethics; Evaluation; Fluorescence; Health facilities; Health services; Histopathology; Laboratories; Likelihood ratio; Medical diagnosis; Medicine and Health Sciences; Mycobacterium ulcerans; Necrosis; Patients; Plastics; Research and Analysis Methods; Rural areas; Sensitivity analysis; Thin layer chromatography; Toxins; Tropical diseases; Ulcers
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0270235

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 assess the 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 us