A stepwise approach to the laboratory diagnosis of Buruli ulcer disease

Abstract

Summaryobjective In view of technical and financial limitations in areas of endemicity, the current practice and recommendations for the laboratory diagnosis of Buruli ulcer disease (BUD) may have to be reconsidered. We reviewed diagnostic results in order to explore options for a modified, more practicable, cost-effective and timely approach to the laboratory diagnosis of BUD.methods Diagnostic specimens from 161 clinically diagnosed BUD patients from four different treatment centres in Ghana were subjected to laboratory analysis. The positivity rates of the laboratory assays were compared.results The number of laboratory-confirmed clinically diagnosed BUD cases with one positive confirmative test was 20% higher than that with two positive confirmative tests. The specificity of microscopy (MIC) and PCR was 96.6% and 100%, respectively. Subsequent analysis of specimens from surgically excised pre-ulcerative tissue-by-tissue MIC and tissue PCR rendered 65% laboratory-confirmed BUD cases. Subsequent analysis of diagnostic swabs from ulcerative lesions by swab smear MIC and swab PCR rendered 70% of laboratory-confirmed BUD cases.conclusions The specificity of the diagnostic tests used in this study suggests that one positive diagnostic test may be considered sufficient for the laboratory confirmation of BUD. Subsequent application of different diagnostic tests rendered a laboratory confirmation of 65% pre-ulcerative and of 70% ulcerative lesions. Implementation of a stepwise, subsequent analysis of diagnostic specimens will result in considerable cost saving compared with simultaneous testing of specimens by several diagnostic assays.

Fine-Needle Aspiration, an Efficient Sampling Technique for Bacteriological Diagnosis of Nonulcerative Buruli Ulcer

“…The second most sensitive confirmation test was DSE, followed by in vitro culture. Comparable observations have been reported in other studies (5,7,23). These findings are analogous to those reported for the use of FNA for the diagnosis of tuberculous lymphadenitis (2,8,15,27).…”

Combining PCR with Microscopy to Reduce Costs of Laboratory Diagnosis of Buruli Ulcer

“…This assertion is supported by the high specificity of ZN in this report using IS2404 by PCR as the gold standard detection method. The specificity of our study was 95.7, and this finding compares very well with a similar study conducted by Bretzel and others 4 in 2006 that had a specificity of 96.6%. 4 PCR will be required as a second confirmation test only if the case involves a new focus.…”

“…The specificity of our study was 95.7, and this finding compares very well with a similar study conducted by Bretzel and others 4 in 2006 that had a specificity of 96.6%. 4 PCR will be required as a second confirmation test only if the case involves a new focus. Nevertheless, the fact that one of the microscopy-positive samples was found to be IS2404 PCR-negative could be a cause for concern, because there are other skin conditions that are caused by AFB-positive bacteria other than M. ulcerans .…”

“…Although both histopathology and cultivation are technically very demanding and time-consuming diagnostic approaches, the fast and less demanding smear microscopy has limited sensitivity. Therefore, IS2404 PCR has become the gold standard diagnostic tool, 4 although its routine use in resource-poor settings is limited by the high costs and need for sophisticated laboratory infrastructure. Therefore, PCR tests are usually not performed at the treating facilities but in bulk at national reference laboratories or outside the endemic country at international reference laboratories.…”

A Genotypic Approach for Detection, Identification, and Characterization of Drug Resistance in Mycobacterium ulcerans in Clinical Samples and Isolates from Ghana

“…Mycobacterial cultures were subjected to a confirmatory IS2404 PCR. 3,5,[18][19][20][21] Samples subjected to sequence analysis. Suspensions of IS2404 PCR confirmed M. ulcerans cultures ( N = 87) dissolved in 700 μL Cell Lysis Solution (Qiagen, Hilden, Germany ) followed by inactivation at 80°C for 20 minutes, and IS2404 PCR-positive whole-genome extracts (total of 156 genome extracts) derived from swab ( N = 68) and tissue samples ( N = 88) were subjected to sequence analysis of rpoB and rpsL genes at the Department of Infectious Diseases and Tropical Medicine, University of Munich (DITM).…”