Analytical performances of the Xpert MTB/RIF assay using stool specimens to improve the diagnosis of pulmonary tuberculosis in Burkina Faso, a tuberculosis endemic country.

Timely diagnosis of Pulmonary Tuberculosis (PTB) is associated with good prognosis, but remains difficult in primary healthcare facilities and particularly in children and patients living with HIV. The aim of this study was to compare the GeneXpert ® MTB/RIF assay (Xpert) performed using a stool sample (3-5 g) and using the first Respiratory Tract Sample (RTS; i.e., sputum, bronchoalveolar or gastric aspirate; as normally done) concomitantly collected from 119 patients with suspected PTB to improve PTB diagnosis in Burkina Faso, a high tuberculosis burden country with limited resources. Overall, microbiological, microscopic and molecular analysis of the 119 first RTS and 119 stool specimens led to Mycobacterium tuberculosis complex detection in 28 patients (23 positive RTS cultures and 5 negative RTS cultures-RTS Xpert positive). When using the 28 clinical confirmed cases as reference standard, the sensitivities of the stool-based and RTS-based Xpert assays were not different (24/28, 85.7%, versus 26/28, 92.86%; p > 0.30), and 22 results were fully concordant. Considering the first RTS culture as the gold standard, the sensitivities of the stool-based and RTS-based Xpert assays to detect PTB in patients with positive RTS culture were 100% (23/23) and 91.3% (21/23), respectively (p >0.05). The stool-based Xpert assay specificity for excluding PTB was 99% (95/96) (compared with 95%, 91/96, when using RTS) and its negative and positive predictive values were 100% (95/95) and 96% (23/24), respectively. Compared with the 23 positive RTS cultures, the incremental yield rates of the RTS-based and stool-based Xpert assays were 4.2% (5/119) and 0.84% (1/119), respectively. Overall, our findings support using the stool-based Xpert assay as an alternative method for earlier PTB diagnosis, when RTS are difficult to obtain.

Confirming Autochthonous Buruli Ulcer Cases in Burkina Faso, West Africa.

Environmental Mycobacterium ulcerans causes a disabling skin disease called Buruli ulcer. Recent studies completed the knowledge of the evolving geographic extension and epidemiology of Buruli ulcer in West Africa, where Côte d'Ivoire is reporting the highest number of cases. We report seven polymerase chain reaction-documented patients in Burkina Faso, a neighboring country of Côte d'Ivoire, where previously Buruli ulcer cases were confirmed primarily using clinical arguments.

Fecal Excretion of Mycobacterium leprae, Burkina Faso.

Mycobacterium leprae was detected by optical microscopy, fluorescent in situ hybridization, and molecular detection in feces collected for the diagnosis of Entamoeba coli enteritis in a leprosy patient in Burkina Faso. This observation raises questions about the role of fecal excretion of M. leprae in the natural history and diagnosis of leprosy.

Performance of a lymphocyte t interferon gamma test (Quantiferon-TB gold in tube) in the diagnosis of active tuberculosis in HIV-infected children.

OBJECTIVE: Evaluate the performance of QuantiFERON ® -TB Gold In-Tube test (QFT-GIT), to improve the diagnosis of active tuberculosis (TB) in Human Immuno-Deficiency Virus (HIV)-infected children. METHOD: Sensitivity, specificity, Positive Predictive Value (PPV), Negative Predictive Value (NPV) of QFT-GIT were assessed in 58/63 HIV-infected children who were suspected of having TB. RESULTS: Sensitivity of QFT-GIT was 20.69%, specificity 96.55%, PPV/NPV respectively 85.71% and 54.90%. CONCLUSION: QFT-GIT appears to be of little contribution to the diagnosis of active TB in children living with HIV in a TB-endemic country.

Fluorescent Hybridization of Mycobacterium leprae in Skin Samples Collected in Burkina Faso.

Leprosy is caused by Mycobacterium leprae, and it remains underdiagnosed in Burkina Faso. We investigated the use of fluorescent in situ hybridization (FISH) for detecting M. leprae in 27 skin samples (skin biopsy samples, slit skin samples, and skin lesion swabs) collected from 21 patients from Burkina Faso and three from Côte d'Ivoire who were suspected of having cutaneous leprosy. In all seven Ziehl-Neelsen-positive skin samples (four skin biopsy samples and three skin swabs collected from the same patient), FISH specifically identified M. leprae, including one FISH-positive skin biopsy sample that remained negative after testing with PCR targeting the rpoB gene and with the GenoType LepraeDR assay. Twenty other skin samples and three negative controls all remained negative for Ziehl-Neelsen staining, FISH, and rpoB PCR. These data indicate the usefulness of a microscopic examination of skin samples after FISH for first-line diagnosis of cutaneous leprosy. Accordingly, FISH represents a potentially useful point-of-care test for the diagnosis of cutaneous leprosy.