Fluorescein diacetate and rapid molecular testing for the early identification of rifampicin resistance in Mali.

BACKGROUND: Non-conversion on auramine smear microscopy indicates a lack of treatment response, possibly associated with initial rifampicin-resistant tuberculosis (RR-TB). However, dead bacteria still stain positive and may be detected. Fluorescein diacetate smear microscopy (FDA) shows live mycobacteria only. Therefore, we studied the potential of 2-month (2M) FDA for the identification of initial RR-TB.METHODS: Between 2015 and 2018, we enrolled new smear-positive pulmonary TB patients from five local centres in Bamako, Mali. After baseline screening, sputum samples were collected at 1M, 2M, 5M and 18M. We used rpoB sequencing to identify initial RR-TB.RESULTS: Of 1359 patients enrolled, 1019 (75%) had rpoB sequencing results. Twenty-six (2.6%, 95%CI: 1.7-3.7) had mutations conferring rifampicin resistance. Most frequent rpoB mutations were located at the codons Asp435Val (42.4%) and Ser450Leu (34.7%). Among patients with initial RR-TB, 72.2% were FDA-negative at 2M (P = 0.2). The positive and negative predictive value of 5M FDA for culture-based failure was respectively 20.0% and 94.7%.CONCLUSION: FDA did not identify the majority of patients with initial RR-TB or culture-based failure. As the full spectrum of mutations identified on sequencing was identified using Xpert, our data support its rapid universal implementation in Mali.

Performance of Mali's biosafety level 3 laboratory in the external quality assessment in preparedness of laboratory accreditation and support to clinical trials.

Background: The external quality assessment (EQA) or external quality control is an evaluation conducted by a certified external organization to inquire about the quality of the results provided by a laboratory. The primary role of EQA is to verify the accuracy of laboratory results. This is essential in research because research data should be published in international peer-reviewed journals, and laboratory results must be repeatable. In 2007, the University Clinical Research Center (UCRC's) biosafety level 3 (BSL-3) laboratory joined the EQA program with the College of American Pathologists in acid-fast staining and culture and identification of mycobacteria as per laboratory accreditation preparedness. Thus, after 11 years of participation, the goal of our study was to evaluate the performance of our laboratory during the different interlaboratory surveys. Methods: We conducted a descriptive retrospective study to evaluate the results of UCRC mycobacteriology laboratory from surveys conducted during 2007 and 2017. Results: Of the 22 evaluations, the laboratory had satisfactory (100% of concordance results) in 18 (81.8%) and good (80% of concordance results) in 4 (18.2%). Overall, the laboratory was above the commended/accepted limits of 75%. Conclusion: So far, UCRC's BSL-3 performed well during the first 11 years of survey participation, and efforts should be deployed to maintain this high quality in the preparedness for laboratory accreditation and support to clinical trials.

Diabetes Mellitus among new tuberculosis patients in Bamako, Mali.

INTRODUCTION: Diabetes Mellitus (DM) increases worldwide, mostly in low- and middle-income countries. In Mali, the prevalence in the adult population is estimated at 1.8%, but tuberculosis (TB) patients are not systematically screened. The goal of our study was to determine the prevalence of DM among newly diagnosed TB patients. METHODS: We conducted a cross sectional study and a pilot prospective cohort study in four health centers in Bamako. All patients underwent fasting capillary-blood glucose (FCBG) test at Day 0, and repeated after one-week of TB treatment. Venous FBG test was performed for discrepancies between the two FCBG results. Thereafter, FCBG was performed for pilot study at month-2 (M2) and M5 of TB treatment. RESULTS: Two hundred and one patients were enrolled in this study. Impaired fasting blood glucose was identified in 17 (8.5%), of whom 11 (5.5%) had DM (VFBG >7 mmol/L). Among patients with DM, seven (63.6%) had successful TB treatment outcome, versus 142 (74.7%) of those without DM (p = 0.64), and (OR: 1.69, 95%CI 0.47-6.02). CONCLUSION: The prevalence of DM among TB patients in Bamako exceeds that of the general population and screening at TB diagnosis suffices to identify those with DM. Systematic screening of both diseases will allow better treatment.

Thermodynamics in the vicinity of a relativistic quantum critical point in 2+1 dimensions.

We study the thermodynamics of the relativistic quantum O(N) model in two space dimensions. In the vicinity of the zero-temperature quantum critical point (QCP), the pressure can be written in the scaling form P(T)=P(0)+N(T(3)/c(2))F(N)(Δ/T), where c is the velocity of the excitations at the QCP and |Δ| a characteristic zero-temperature energy scale. Using both a large-N approach to leading order and the nonperturbative renormalization group, we compute the universal scaling function F(N). For small values of N (N/~1) regimes, but fails to describe the nonmonotonic behavior of F(N) in the quantum critical regime. We discuss the renormalization-group flows in the various regimes near the QCP and make the connection with the quantum nonlinear sigma model in the renormalized classical regime. We compute the Berezinskii-Kosterlitz-Thouless transition temperature in the quantum O(2) model and find that in the vicinity of the QCP the universal ratio T(BKT)/ρ(s)(0) is very close to π/2, implying that the stiffness ρ(s)(T(BKT)(-)) at the transition is only slightly reduced with respect to the zero-temperature stiffness ρ(s)(0). Finally, we briefly discuss the experimental determination of the universal function F(2) from the pressure of a Bose gas in an optical lattice near the superfluid-Mott-insulator transition.