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.

Evaluation of the impact of COVID-19 in people coinfected with HIV and/or tuberculosis in low-income countries: study protocol for mixed methods research in Burkina Faso.

BACKGROUND: An issue of particular concern is the impact of the 2019 novel coronavirus (2019 nCOV) on the people coinfected with the Human Immuno-deficiency Virus (HIV) and/or tuberculosis (TB). Unfortunately, this interaction has not been well explored in African despite the large proportion of these risk populations living with HIV and/or patients and/or tuberculosis (TB) in the African region. This study aims to design a research protocol for assessment of the impact of coronavirus disease 2019 (COVID-19) on these risk populations in response to COVID-19 strategic plans in Burkina Faso by generating serological, epidemiological, virological, clinical and socio-anthropological evidence-based data. METHODS: A multidisciplinary research will be conducted in the city of Bobo-Dioulasso, Burkina Faso using mixed methods. Data will be collected from a cohort of people living with HIV and/or TB patients in the city (i) to determine the proportion of people with specific antibodies against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using retrospective data ; (ii) to determine the proportion of people infected with Covid-19 and the dynamics of viral loads and antibodies in these people based on prospective data; (iii) to identify circulating SARS-COV-2 variants and novel biomarkers using prospective data ; (iv) to analyze perceptions, community experiences and response strategies during the public health emergencies imposed by COVID-19 through a qualitative study. DISCUSSION: This study will generate factual and comprehensive data that will contribute in improving response strategies to COVID-19 and the other possible emerging diseases with keen interest on the risk populations living with HIV and/or TB infected patients.

Bronchial challenge test in asthmatics sensitized to mites: role of particle size in bronchial response.

Although major house dust mite allergen (Der p 1) is carried mainly on large particles (>10 microm), standard bronchial challenge tests (BCT) use nebulizers that deliver smaller particles (sizes from 1 to 5 microm) and may therefore not reflect actual domestic exposure. The objective of this study was to evaluate the influence of particle size of Dermatophagoides pteronyssinus extract on bronchial response. Specific BCT were performed with different mass median aerodynamic diameters (MMAD): 1.1, 5.6, and 9.7 microm. Each of the 19 mite-sensitized patients underwent mite BCT three times, once with each nebulizer. IL-5 levels were assessed in induced sputum and blood samples. The PD(20) for Der p 1 differed substantially with particle size, with less Der p 1 (11.2 ng) needed to produce a PD(20) with the largest particles (9.7 microm), compared to 18.1 ng for the 5.6 microm particles and 142.5 ng for the 1.1 microm particles (p < 0.0001). Large particles also induced an early phase response significantly more often than small particles (100% vs. 63%). Although the late phase reaction (LPR) frequency was similar with all three particle sizes, lower mean oral corticosteroid doses were needed to treat LPR with the largest particles (23 mg), compared to the smaller particles, with 34 mg for the 5.6 microm particles and 51 mg for the 1.1 microm. The 1.1 microm particles produced a significantly greater increase in IL-5 concentrations in sputum and blood compared to the larger particles. Large particles clearly play a role in the immediate bronchial response in asthmatics sensitized to mites and, therefore, should be included in pharmacological studies in humans.

Controlling indoor allergens.

PURPOSE OF REVIEW: Epidemiological surveys indicate that there has been a notable increase in the prevalence of asthma and other allergic diseases in children and adults. The purpose of this review is to report and comment on recent studies about the role of allergen in primary prevention and to seek new insights on the effects of allergen control in allergic patients. RECENT FINDINGS: This paper deals with allergen reduction in primary prevention, the effect of early exposure to pets on atopic diseases and the development of new occupational activity improving allergen control in allergic patients. SUMMARY: The role of allergen dose involved in the onset of atopy is controversial. Studies hypothesizing that a reduction of allergen dose might reduce atopy failed to confirm the data from the Isle of Wight study and found no effect on the frequency of immunoglobulin E sensitization. This effect might nonetheless occur later in life. Other studies indicate that high doses of allergen early in life have a protective effect against cat and dog sensitization. Only one retrospective study found that cat exposure was protective against cat sensitization. A German prospective study suggested, however, that it is more probable that cat allergen exposure is harmfully related to sensitization, by increasing IgE synthesis. The effect of high doses must be clarified by further prospective studies. Accordingly, we must be very careful when giving advice on primary prevention, particularly about the protective effect of cat and dog allergens. Secondary prevention may be dramatically improved with the help of a new occupational activity: the medical indoor environment counsellor.