Journal Article > ResearchFull Text
BMC Pediatr. 2014 January 20; Volume 133 (Issue 2); DOI:10.1542/peds.2013-2112
Page AL, de Rekeneire N, Sayadi S, Aberrane S, Janssens AC, et al.
BMC Pediatr. 2014 January 20; Volume 133 (Issue 2); DOI:10.1542/peds.2013-2112
Early recognition of bacterial infections is crucial for their proper management, but is particularly difficult in children with severe acute malnutrition (SAM). The objectives of this study were to evaluate the accuracy of C-reactive protein (CRP) and procalcitonin (PCT) for diagnosing bacterial infections and assessing the prognosis of hospitalized children with SAM, and to determine the reliability of CRP and PCT rapid tests suitable for remote settings.
Journal Article > ResearchFull Text
PLOS One. 2015 April 17; Volume 10 (Issue 4); DOI:10.1371/journal.pone.0122433
Kosack CS, de Kieviet W, Bayrak K, Milovic A, Page AL
PLOS One. 2015 April 17; Volume 10 (Issue 4); DOI:10.1371/journal.pone.0122433
Creatinine is a parameter that is required to monitor renal function and is important to follow in patients under treatment with potentially toxic renal drugs, such as the anti-HIV drug Tenofovir. A point of care instrument to measure creatinine would be useful for patients monitoring in resource-limited settings, where more instruments that are sophisticated are not available. The StatSensor Xpress Creatinine (Nova Biomedical Cooperation, Waltham, MA, USA) point of care analyzer was evaluated for its diagnostic performance in indicating drug therapy change. Creatinine was measured in parallel using the Nova StatSensor Xpress Creatinine analyzer and the Vitros 5,1FS (Ortho Clinical Diagnostics, Inc, Rochester, USA), which served as reference standard. The precision (i.e., repeatability and reproducibility) and accuracy of the StatSensor Xpress Creatinine analyzer were calculated using a panel of specimens with normal, low pathological and high pathological values. Two different Nova StatSensor Xpress Creatinine analyzers were used for the assessment of accuracy using repeated measurements. The coefficient of variation of the StatSensor Xpress Creatinine analyzers ranged from 2.3 to 5.9% for repeatability and from 4.2 to 9.0% for between-run reproducibility. The concordance correlation agreement was good except for high values (>600 µmol/L). The Bland-Altman analysis in high pathological specimens suggests that the Nova StatSensor Xpress Creatinine test tends to underestimate high creatinine values (i.e., >600 µmol/L). The Nova StatSensor Xpress Creatinine analyzers showed acceptable to good results in terms of repeatability, inter-device reproducibility and between-run reproducibility over time using quality control reagents. The analyzer was found sufficiently accurate for detecting pathological values in patients (age >10 year) and can be used with a moderate risk of misclassification.
Journal Article > ResearchFull Text
PLOS One. 2012 March 19; Volume 7 (Issue 3); DOI:10.1371/journal.pone.0033704
Kosack CS, Page AL, Van Hulsteijn LT, Lentjes EG
PLOS One. 2012 March 19; Volume 7 (Issue 3); DOI:10.1371/journal.pone.0033704
Thyroid-stimulating hormone (TSH) promotes expression of thyroid hormones which are essential for metabolism, growth, and development. Second-line drugs to treat tuberculosis (TB) can cause hypothyroidism by suppressing thyroid hormone synthesis. Therefore, TSH levels are routinely measured in TB patients receiving second-line drugs, and thyroxin treatment is initiated where indicated. However, standard TSH tests are technically demanding for many low-resource settings where TB is prevalent; a simple and inexpensive test is urgently needed.
Journal Article > ResearchFull Text
Epidemiol Infect. 2020 March 13; Volume 148; DOI:10.1017/S095026882000062X
Ferreras E, Blake A, Chewe O, Mwaba J, Zulu G, et al.
Epidemiol Infect. 2020 March 13; Volume 148; DOI:10.1017/S095026882000062X
We conducted a matched case-control (MCC), test-negative case-control (TNCC) and case-cohort study in 2016 in Lusaka, Zambia, following a mass vaccination campaign. Confirmed cholera cases served as cases in all three study designs. In the TNCC, control-subjects were cases with negative cholera culture and polymerase chain reaction results. Matched controls by age and sex were selected among neighbours of the confirmed cases in the MCC study. For the case-cohort study, we recruited a cohort of randomly selected individuals living in areas considered at-risk of cholera. We recruited 211 suspected cases (66 confirmed cholera cases and 145 non-cholera diarrhoea cases), 1055 matched controls and a cohort of 921. Adjusted vaccine effectiveness of one dose of oral cholera vaccine (OCV) was 88.9% (95% confidence interval (CI) 42.7–97.8) in the MCC study, 80.2% (95% CI: 16.9–95.3) in the TNCC design and 89.4% (95% CI: 64.6–96.9) in the case-cohort study. Three study designs confirmed the short-term effectiveness of single dose OCV. Major healthcare-seeking behaviour bias did not appear to affect our estimates. Most of the protection among vaccinated individuals could be attributed to the direct effect of the vaccine.
Journal Article > ResearchFull Text
PLOS One. 2010 June 11; Volume 5 (Issue 6); DOI:10.1371/journal.pone.0011086
Rose AMC, Mueller JE, Gerstl S, Njanpop-Lafourcade BM, Page AL, et al.
PLOS One. 2010 June 11; Volume 5 (Issue 6); DOI:10.1371/journal.pone.0011086
Meningococcal meningitis outbreaks occur every year during the dry season in the "meningitis belt" of sub-Saharan Africa. Identification of the causative strain is crucial before launching mass vaccination campaigns, to assure use of the correct vaccine. Rapid agglutination (latex) tests are most commonly available in district-level laboratories at the beginning of the epidemic season; limitations include a short shelf-life and the need for refrigeration and good technical skills. Recently, a new dipstick rapid diagnostic test (RDT) was developed to identify and differentiate disease caused by meningococcal serogroups A, W135, C and Y. We evaluated the diagnostic performance of this dipstick RDT during an urban outbreak of meningitis caused by N. meningitidis serogroup A in Ouagadougou, Burkina Faso; first against an in-country reference standard of culture and/or multiplex PCR; and second against culture and/or a highly sensitive nested PCR technique performed in Oslo, Norway. We included 267 patients with suspected acute bacterial meningitis. Using the in-country reference standard, 50 samples (19%) were positive. Dipstick RDT sensitivity (N = 265) was 70% (95%CI 55-82) and specificity 97% (95%CI 93-99). Using culture and/or nested PCR, 126/259 (49%) samples were positive; dipstick RDT sensitivity (N = 257) was 32% (95%CI 24-41), and specificity was 99% (95%CI 95-100). We found dipstick RDT sensitivity lower than values reported from (i) assessments under ideal laboratory conditions (>90%), and (ii) a prior field evaluation in Niger [89% (95%CI 80-95)]. Specificity, however, was similar to (i), and higher than (ii) [62% (95%CI 48-75)]. At this stage in development, therefore, other tests (e.g., latex) might be preferred for use in peripheral health centres. We highlight the value of field evaluations for new diagnostic tests, and note relatively low sensitivity of a reference standard using multiplex vs. nested PCR. Although the former is the current standard for bacterial meningitis surveillance in the meningitis belt, nested PCR performed in a certified laboratory should be used as an absolute reference when evaluating new diagnostic tests.
Journal Article > ResearchFull Text
PLOS One. 2015 February 6; Volume 10 (Issue 2); DOI:10.1371/journal.pone.0118191
Orikiriza P, Tibenderana B, Siedner MJ, Mueller YK, Byarugaba F, et al.
PLOS One. 2015 February 6; Volume 10 (Issue 2); DOI:10.1371/journal.pone.0118191
There are limited data on region-specific drug susceptibility of tuberculosis (TB) in Uganda. We performed resistance testing on specimens collected from treatment-naive patients with pulmonary TB in Southwestern Uganda for first and second line anti-TB drugs. We sought to provide data to guide regional recommendations for empiric TB therapy.
Journal Article > ResearchFull Text
PLoS Negl Trop Dis. 2013 August 15; Volume 7 (Issue 8); DOI:10.1371/journal.pntd.0002366
Martinez-Pino I, Luquero FJ, Sakoba K, Sylla S, Haile M, et al.
PLoS Negl Trop Dis. 2013 August 15; Volume 7 (Issue 8); DOI:10.1371/journal.pntd.0002366
During the 2012 cholera outbreak in the Republic of Guinea, the Ministry of Health, supported by Médecins Sans Frontières - Operational Center Geneva, used the oral cholera vaccine Shanchol as a part of the emergency response. The rapid diagnostic test (RDT) Crystal VC, widely used during outbreaks, detects lipopolysaccharide antigens of Vibrio cholerae O1 and O139, both included in Shanchol. In the context of reactive use of a whole-cell cholera vaccine in a region where cholera cases have been reported, it is essential to know what proportion of vaccinated individuals would be reactive to the RDT and for how long after vaccination.
Journal Article > ResearchFull Text
Trop Med Int Health. 2018 May 31; Volume 23 (Issue 8); 834-840.; DOI:10.1111/tmi.13084
Mwaba J, Ferreras E, Chizema Kawesha E, Mwimbe D, Tafirenyika F, et al.
Trop Med Int Health. 2018 May 31; Volume 23 (Issue 8); 834-840.; DOI:10.1111/tmi.13084
OBJECTIVE
To assess the performance of the SD Bioline Cholera Ag O1/O139 rapid diagnostic test (RDT) compared to a reference standard combining culture and PCR for the diagnosis of cholera cases during an outbreak.
METHODS
RDT and bacterial culture were performed on site using fresh stools collected from cholera suspected cases, and from stools enriched in alkaline peptone water. Dried stool samples on filter paper were tested for V. cholerae by PCR in Lusaka (as part of a laboratory technology transfer project) and at a reference laboratory in Paris, France. A sample was considered positive for cholera by the reference standard if any of the culture or PCR tests was positive for V. cholerae O1 or O139.
RESULTS
Among the 170 samples tested with SD Bioline and compared to the reference standard, the RDT showed a sensitivity of 90.9% (95% CI: 81.3-96.6) and specificity of 95.2% (95% CI: 89.1-98.4). After enrichment, the sensitivity was 95.5% (95% CI: 87.3-99.1) and specificity 100% (95% CI: 96.5-100).
CONCLUSION
The observed sensitivity and specificity were within recommendations set by the Global Task Force for Cholera Control on the use of cholera RDT (sensitivity = 90%; specificity = 85%). Although the sample size was small, our findings suggest that the SD Bioline RDT could be used in the field to rapidly alert public health officials to the likely presence of cholera cases when an outbreak is suspected.
To assess the performance of the SD Bioline Cholera Ag O1/O139 rapid diagnostic test (RDT) compared to a reference standard combining culture and PCR for the diagnosis of cholera cases during an outbreak.
METHODS
RDT and bacterial culture were performed on site using fresh stools collected from cholera suspected cases, and from stools enriched in alkaline peptone water. Dried stool samples on filter paper were tested for V. cholerae by PCR in Lusaka (as part of a laboratory technology transfer project) and at a reference laboratory in Paris, France. A sample was considered positive for cholera by the reference standard if any of the culture or PCR tests was positive for V. cholerae O1 or O139.
RESULTS
Among the 170 samples tested with SD Bioline and compared to the reference standard, the RDT showed a sensitivity of 90.9% (95% CI: 81.3-96.6) and specificity of 95.2% (95% CI: 89.1-98.4). After enrichment, the sensitivity was 95.5% (95% CI: 87.3-99.1) and specificity 100% (95% CI: 96.5-100).
CONCLUSION
The observed sensitivity and specificity were within recommendations set by the Global Task Force for Cholera Control on the use of cholera RDT (sensitivity = 90%; specificity = 85%). Although the sample size was small, our findings suggest that the SD Bioline RDT could be used in the field to rapidly alert public health officials to the likely presence of cholera cases when an outbreak is suspected.
Journal Article > ResearchFull Text
PLOS One. 2015 December 15; Volume 10 (Issue 12); e0144656.; DOI:10.1371/journal.pone.0144656
Ardizzoni E, Fajardo E, Saranchuk P, Casenghi M, Page AL, et al.
PLOS One. 2015 December 15; Volume 10 (Issue 12); e0144656.; DOI:10.1371/journal.pone.0144656
BACKGROUND
The Xpert® MTB/RIF (Xpert) is an automated molecular test for simultaneous detection of tuberculosis (TB) and rifampicin resistance, recommended by the World Health Organization as the preferred diagnostic method for individuals presumed to have multi-drug resistant TB (MDR-TB) or HIV-associated TB. We describe the performance of Xpert and key lessons learned during two years of implementation under routine conditions in 33 projects located in 18 countries supported by Médecins Sans Frontières across varied geographic, epidemiological and clinical settings.
METHODS
Xpert was used following three strategies: the first being as the initial test, with microscopy in parallel, for all presumptive TB cases; the second being only for patients at risk of MDR-TB, or with HIV- associated TB, or presumptive paediatric TB; and the third being as the initial test for these high-risk patients plus as an add-on test to microscopy in others. Routine laboratory data were collected, using laboratory registers. Qualitative data such as logistic aspects, human resources, and tool acceptance were collected using a questionnaire.
FINDINGS
In total, 52,863 samples underwent Xpert testing from April 2011 to December 2012. The average MTB detection rate was 18.5%, 22.3%, and 11.6% for the three different strategies respectively. Analysis of the results on samples tested in parallel showed that using Xpert as add-on test to microscopy would have increased laboratory TB confirmation by 49.7%, versus 42.3% for Xpert replacing microscopy. The main limitation of the test was the high rate of inconclusive results, which correlated with factors such as defective modules, cartridge version (G3 vs. G4) and staff experience. Operational and logistical hurdles included infrastructure renovation, basic computer training, regular instrument troubleshooting and maintenance, all of which required substantial and continuous support.
CONCLUSION
The implementation of Xpert was feasible and significantly increased TB detection compared to microscopy, despite the high rate of inconclusive results. Xpert implementation was accompanied by considerable operational and logistical challenges. To further decentralize diagnosis, simpler, low-cost TB technologies well-suited to low-resource settings are still urgently needed.
The Xpert® MTB/RIF (Xpert) is an automated molecular test for simultaneous detection of tuberculosis (TB) and rifampicin resistance, recommended by the World Health Organization as the preferred diagnostic method for individuals presumed to have multi-drug resistant TB (MDR-TB) or HIV-associated TB. We describe the performance of Xpert and key lessons learned during two years of implementation under routine conditions in 33 projects located in 18 countries supported by Médecins Sans Frontières across varied geographic, epidemiological and clinical settings.
METHODS
Xpert was used following three strategies: the first being as the initial test, with microscopy in parallel, for all presumptive TB cases; the second being only for patients at risk of MDR-TB, or with HIV- associated TB, or presumptive paediatric TB; and the third being as the initial test for these high-risk patients plus as an add-on test to microscopy in others. Routine laboratory data were collected, using laboratory registers. Qualitative data such as logistic aspects, human resources, and tool acceptance were collected using a questionnaire.
FINDINGS
In total, 52,863 samples underwent Xpert testing from April 2011 to December 2012. The average MTB detection rate was 18.5%, 22.3%, and 11.6% for the three different strategies respectively. Analysis of the results on samples tested in parallel showed that using Xpert as add-on test to microscopy would have increased laboratory TB confirmation by 49.7%, versus 42.3% for Xpert replacing microscopy. The main limitation of the test was the high rate of inconclusive results, which correlated with factors such as defective modules, cartridge version (G3 vs. G4) and staff experience. Operational and logistical hurdles included infrastructure renovation, basic computer training, regular instrument troubleshooting and maintenance, all of which required substantial and continuous support.
CONCLUSION
The implementation of Xpert was feasible and significantly increased TB detection compared to microscopy, despite the high rate of inconclusive results. Xpert implementation was accompanied by considerable operational and logistical challenges. To further decentralize diagnosis, simpler, low-cost TB technologies well-suited to low-resource settings are still urgently needed.
Journal Article > CommentaryFull Text
J Int AIDS Soc. 2017 July 19; Volume 20 (Issue 1); DOI:10.7448/IAS.20.1.22098
Kosack CS, Page AL, Beelaert G, Benson TT, Savane A, et al.
J Int AIDS Soc. 2017 July 19; Volume 20 (Issue 1); DOI:10.7448/IAS.20.1.22098