Journal Article > ResearchFull Text
PLOS One. 31 May 2011; Volume 6 (Issue 5); DOI:10.1371/journal.pone.0020175
Bonnet MMB, Gagnidze L, Guerin PJ, Bonte L, Ramsay AR, et al.
PLOS One. 31 May 2011; Volume 6 (Issue 5); DOI:10.1371/journal.pone.0020175
Sputum microscopy is the only diagnostic for tuberculosis (TB) available at peripheral levels of health service in resource-poor countries. Its sensitivity is reduced in high HIV-prevalence settings. Sodium hypochlorite (NaOCl) specimen sedimentation prior microscopy and light-emitting diode (LED)-fluorescence microscopy (FM) can individually improve performance of microscopy. This study aimed to evaluate the performance of combined LED-FM and NaOCl sputum sedimentation for TB detection at peripheral level of health services.
Journal Article > ResearchFull Text
PLOS One. 5 October 2009; Volume 4 (Issue 10); DOI:10.1371/journal.pone.0007326
Rose AMC, Gerstl S, Mahamane AE, Sidikou F, Djibo S, et al.
PLOS One. 5 October 2009; Volume 4 (Issue 10); DOI:10.1371/journal.pone.0007326
The Pastorex((R)) (BioRad) rapid agglutination test is one of the main rapid diagnostic tests (RDTs) for meningococcal disease currently in use in the "meningitis belt". Earlier evaluations, performed after heating and centrifugation of cerebrospinal fluid (CSF) samples, under good laboratory conditions, showed high sensitivity and specificity. However, during an epidemic, the test may be used without prior sample preparation. Recently a new, easy-to-use dipstick RDT for meningococcal disease detection on CSF was developed by the Centre de Recherche Médicale et Sanitaire in Niger and the Pasteur Institute in France. We estimate diagnostic accuracy in the field during the 2006 outbreak of Neisseria meningitidis serogroup A in Maradi, Niger, for the dipstick RDT and Pastorex((R)) on unprepared CSF, (a) by comparing each test's sensitivity and specificity with previously reported values; and (b) by comparing results for each test on paired samples, using McNemar's test. We also (c) estimate diagnostic accuracy of the dipstick RDT on diluted whole blood. We tested unprepared CSF and diluted whole blood from 126 patients with suspected meningococcal disease presenting at four health posts. (a) Pastorex((R)) sensitivity (69%; 95%CI 57-79) was significantly lower than found previously for prepared CSF samples [87% (81-91); or 88% (85-91)], as was specificity [81% (95%CI 68-91) vs 93% (90-95); or 93% (87-96)]. Sensitivity of the dipstick RDT [89% (95%CI 80-95)] was similar to previously reported values for ideal laboratory conditions [89% (84-93) and 94% (90-96)]. Specificity, at 62% (95%CI 48-75), was significantly lower than found previously [94% (92-96) and 97% (94-99)]. (b) McNemar's test for the dipstick RDT vs Pastorex((R)) was statistically significant (p<0.001). (c) The dipstick RDT did not perform satisfactorily on diluted whole blood (sensitivity 73%; specificity 57%).Sensitivity and specificity of Pastorex((R)) without prior CSF preparation were poorer than previously reported results from prepared samples; therefore we caution against using this test during an epidemic if sample preparation is not possible. For the dipstick RDT, sensitivity was similar to, while specificity was not as high as previously reported during a more stable context. Further studies are needed to evaluate its field performance, especially for different populations and other serogroups.
Journal Article > ResearchFull Text
J Clin Microbiol. 30 May 2012; Volume 50 (Issue 8); DOI:10.1128/JCM.01232-12
Schramm B, Hewison CCH, Bonte L, Jones W, Camelique O, et al.
J Clin Microbiol. 30 May 2012; Volume 50 (Issue 8); DOI:10.1128/JCM.01232-12
Simple tuberculosis (TB) treatment monitoring tools are needed. We assessed the performance of fluorescein-diacetate (FDA) smear microscopy for detection of viable Mycobacterium tuberculosis in sputum specimens (n = 288) of TB cases under treatment compared to culture (17.4% culture positivity). FDA sensitivity was moderate (83.7% [95% confidence interval {CI}, 70.3 to 92.6]), and specificity was low (66.1% [59.5 to 72.2]). The good negative predictive value (94.8% [90.1 to 97.8]) and negative likelihood ratio (0.2) suggest using this method to rule out treatment failure in settings without access to culture.
Journal Article > ResearchFull Text
J Clin Microbiol. 3 June 2009; Volume 47 (Issue 8); DOI:10.1128/JCM.00264-09
Martin AIC, Munga Waweru P, Babu Okatch F, Amondi Ouma N, Bonte L, et al.
J Clin Microbiol. 3 June 2009; Volume 47 (Issue 8); DOI:10.1128/JCM.00264-09
The objective of this study was to evaluate the performance of a low-cost method, the Thin Layer Agar (TLA), for the diagnosis of smear-negative patients. This prospective study was performed in Homa Bay district Hospital in Kenya. Out of 1584 smear-negative sputum samples, 212 were positive by Löwenstein-Jensen (LJ) (13.5%) and 220 positive by TLA (14%). The sensitivity of LJ and TLA was 71% and 74 % respectively. TLA could become an affordable method for the diagnosis of smear-negative tuberculosis in resource-limited settings with results available within 2 weeks.
Journal Article > ResearchFull Text
PLOS One. 18 February 2011; Volume 6 (Issue 2); DOI:10.1371/journal.pone.0017214
Bonnet MMB, Gagnidze L, Githui W, Guerin PJ, Bonte L, et al.
PLOS One. 18 February 2011; Volume 6 (Issue 2); DOI:10.1371/journal.pone.0017214
Sputum microscopy is the only tuberculosis (TB) diagnostic available at peripheral levels of care in resource limited countries. Its sensitivity is low, particularly in high HIV prevalence settings. Fluorescence microscopy (FM) can improve performance of microscopy and with the new light emitting diode (LED) technologies could be appropriate for peripheral settings. The study aimed to compare the performance of LED-FM versus Ziehl-Neelsen (ZN) microscopy and to assess feasibility of LED-FM at a low level of care in a high HIV prevalence country.
Journal Article > ResearchFull Text
Trans R Soc Trop Med Hyg. 14 February 2008
Guthmann JP, Ruiz A, Priotto G, Kiguli J, Bonte L, et al.
Trans R Soc Trop Med Hyg. 14 February 2008
A study was conducted to measure the overall performance of several rapid diagnostic tests for Plasmodium falciparum infection, in order to select the most appropriate test to be used in the field. A total of 742 patients attending the out-patient department of Mbarara Hospital with a clinical suspicion of malaria were included in the study. For each patient, a thick/thin film and 5 rapid tests based on the detection of histidine-rich protein II (HRP-II) (Paracheck Pf dipstick and device, ParaHIT f, Malaria Rapid and BIO P.F.) were performed. Outcomes were validity, inter-reader reliability and 'ease of use in the field', measured by both the general characteristics of the test and by the opinion of the readers. About half (57%) of the patients were positive for P. falciparum. The Paracheck Pf (dipstick and device) was considered as the most appropriate for the use in the field, being sensitive (97%), moderately specific (88%), reliable (kappa coefficient = 0.97), easy to use and cheap (about US$ 0.5/test). The ParaHIT f represented a good alternative.
Journal Article > ResearchAbstract Only
Science. 10 November 2017; Volume 358 (Issue 6364); 785-789.; DOI:10.1126/science.aad5901
Weill FX, Domman D, Njamkepo E, Tarr C, Rauzier J, et al.
Science. 10 November 2017; Volume 358 (Issue 6364); 785-789.; DOI:10.1126/science.aad5901
The seventh cholera pandemic has heavily affected Africa, although the origin and continental spread of the disease remain undefined. We used genomic data from 1070 Vibrio cholerae O1 isolates, across 45 African countries and over a 49-year period, to show that past epidemics were attributable to a single expanded lineage. This lineage was introduced at least 11 times since 1970, into two main regions, West Africa and East/Southern Africa, causing epidemics that lasted up to 28 years. The last five introductions into Africa, all from Asia, involved multidrug-resistant sublineages that replaced antibiotic-susceptible sublineages after 2000. This phylogenetic framework describes the periodicity of lineage introduction and the stable routes of cholera spread, which should inform the rational design of control measures for cholera in Africa.
Journal Article > ResearchFull Text
Trans R Soc Trop Med Hyg. 1 October 2006; Volume 100 (Issue 10); DOI:10.1016/j.trstmh.2005.11.014
Fryland M, Chaillet P, Zachariah R, Barnaba A, Bonte L, et al.
Trans R Soc Trop Med Hyg. 1 October 2006; Volume 100 (Issue 10); DOI:10.1016/j.trstmh.2005.11.014
A study was conducted in rural Malawi to verify (a) whether the Partec CyFlow Counter((R)) for CD4+ T-cell lymphocyte counting in HIV-positive individuals could be introduced into a district hospital laboratory and (b) whether it would produce CD4 counts of acceptable quality. CD4+ cell counting was performed using the Partec CyFlow Counter and the results were compared with a reference method (FACsCount). A total of 311 blood samples were analysed and the correlation coefficient for the CyFlow Counter was 0.92 (95% CI 0.89-0.95). Mean CD4 counts using the Partec and the reference methods were 308.2 cells/microl and 316.9 cells/microl, respectively. The mean difference in CD4 count values was -8.68 cells/microl (95% CI -18.8 to 1.4). Mean intra-run variation was -6.84 cells/microl (95% CI -12.9 to 0.79). In the district laboratory setting, the instrument could accommodate up to 75 blood samples per technician per day. After being trained, local laboratory staff found the CyFlow Counter procedures simple to run and the instrument easy to manipulate. The Partec CyFlow Counter produces sufficiently reliable results and the instrument appears robust under field conditions. It could provide a new option for introducing routine CD4+ cell monitoring at the district level in the context of scaling-up antiretroviral therapy in Malawi.
Journal Article > ResearchFull Text
J Clin Microbiol. 21 December 2020; Volume 47 (Issue 8); 2632-2634.; DOI: 10.1128/JCM.00264-09
Martin AIC, Munga Waweru P, Babu Okatch F, Amondi Ouma N, Bonte L, et al.
J Clin Microbiol. 21 December 2020; Volume 47 (Issue 8); 2632-2634.; DOI: 10.1128/JCM.00264-09
The objective of this study was to evaluate the performance of a low-cost method, the thin layer agar (TLA) method, for the diagnosis of smear-negative patients. This prospective study was performed in Homa Bay District Hospital in Kenya. Out of 1,584 smear-negative sputum samples, 212 (13.5%) were positive by culture in Löwenstein-Jensen medium (LJ) and 220 (14%) were positive by the TLA method. The sensitivities of LJ and TLA were 71% and 74%, respectively. TLA could become an affordable method for the diagnosis of smear-negative tuberculosis in resource-limited settings, with results available within 2 weeks.