Validation of the point-of-care (POC) technologies Xpert HIV-1 Qual and m-PIMA HIV 1/2 detect for early diagnosis of HIV-1 and HIV-2 in Senegal.

Introduction: early infant diagnosis (EID) is crucial in the prevention of mother to child transmission (PMTCT) of human immunodeficiency virus (HIV) and is an essential component for the elimination of HIV. EID can be strengthened in resource-limited countries by the introduction and the roll out of real-time polymerase chain reaction (PCR) technologies via point-of-care (POC) devices which improves treatment in remote areas and reduces turnaround time for clinicians and patients to receive results and linkage to care. The objective of this study was to evaluate the performance of Xpert® HIV-1 Qual Assay (Cepheid) and m-PIMA™ HIV 1/2 Detect (ABBOTT) for EID of HIV-1 and HIV-2. Methods: the performance of the Xpert® HIV-1 qual device was evaluated with 192 samples including 100 dried blood spot (DBS) samples from the National Reference Laboratory biobank (71 negative and 29 positive samples) and an additional 92 whole blood samples collected from infants from neonatal departments. These infants from seven treatment centers in the Dakar region were born to mothers infected with HIV-1 (n=91), HIV-2 (n= 8) or HIV-1/2 (n=1). The m-PIMA™ HIV 1/2 detect assay was evaluated on whole blood samples (n=100) with 92 HIV-1 samples and 8 HIV-2 samples from children born to HIV-infected mothers. The Cobas AmpliPreP/Cobas TaqMan (CAP/CTM) platform from Roche Diagnostic Laboratories was used as a reference for HIV-1 diagnosis and the Generic HIV-2 Viral Load Assay (Biocentric) was used as a reference for HIV-2 diagnosis. Performance was evaluated by calculating sensitivity (Se), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV) and Cohen's kappa coefficient. Results: for HIV-1 detection on GeneXpert and m-PIMA, no discordance was found on the samples tested, i.e. a sensitivity of 100% (95% CI: 93.9-100%), a specificity of 100% (95% CI: 97.5-100%), a positive predictive value (PPV) of 100% (95% CI: 93.9-100%) and a negative predictive value (NPV) of 100% (95% CI: 97.5-100%). Agreement with Cobas AmpliPrep/Cobas TaqMan (CAP/CTM) was 100% with a Kappa coefficient of 1 (p<0.001, 95% CI) for both techniques. Similarly, the comparison between m-PIMA and generic biocentric for the detection of HIV-2 on the 8 samples tested showed perfect agreement. Conclusion: these results confirm the excellent performance of the Xpert® HIV-1 qual and m-PIMA™ HIV1/2 detect tests for the detection of HIV-1 and HIV-2 and encourage the extension of POC tests to improve access to EID in Senegal.

Comparison of Amplix® hepatitis B virus and Roche COBAS AmpliPrep/COBAS Taqman hepatitis B virus assay in quantifying HBV DNA in plasma of chronic hepatitis B in Senegal.

INTRODUCTION: quantification of hepatitis B virus DNA, a key element in the management of chronic hepatitis B, allows a more direct and reliable measurement of viral replication and monitoring of the virological response to therapy. Polymerase chain reaction (PCR) platforms performing this quantification and adaptable to intermediate laboratories have been developed. Thus, this study was conducted to evaluate the on-site performance of the AMPLIX® hepatitis B virus (HBV) real-time PCR technique in comparison with the COBAS AmpliPrep™ technique. METHODS: performance of the AMPLIX® HBV real-time PCR technique was evaluated with repeatability and intermediate precision (reproducibility) determined. The comparison with COBAS Taqman was performed by testing, in parallel, 42 plasma samples. The statistical analysis using Meth Val® software was focused on correlation and concordance determination. RESULTS: AMPLIX® real-time PCR assay showed good reproducibility for the low (CV=6.65%) and high (CV=3.15%) control levels but also good repeatability for both the low (CV=2.12%) and high (CV=1.60%) concentration levels. Accuracy obtained in our study were less than acceptability limit fixed to 5%. Viral load measurements between Amplix and COBAS Taqman correlated strongly with a correlation coefficient of 0.97%. Concordance analysis gave an average of the differences of 0.54 log IU/L between the viral load measurements of the 2 techniques. CONCLUSION: based on these results, the Amplix real-time PCR platform for the quantification of HBV DNA can be considered as a reliable system for the monitoring of chronic hepatitis B and also a system adapted to intermediate laboratories.

[Blood biomarkers of early diagnosis for neonatal bacterial infections: back from Senegal cohort]. / Biomarqueurs sanguins du diagnostic précoce des infections néonatales bactériennes : retour d'expérience d'une cohorte sénégalaise.

In Senegal, reducing neonatal mortality remains a challenge. The management of neonatal infections remains problematic and presents a strong clinical focus. Indeed, like all developing countries, the difficulty of acquiring state-of-the-art infrastructure and the financial cost impact on the routine use of biomarkers. It is in this context that we conducted this study to identify the best biological strategy for making a reliable diagnosis. Ninety-nine newborns were recruited at the pediatric service of the Diamniadio Children's Hospital (Senegal). CRP was assayed by latex immuno-agglutination method, IL-6 and IL-8 using Luminex® technology, PCT by chemiluminescence, orosomucoid by immunoturbidimetry and SAA by ELISA technique. 20 newborns had probable infection and six established infection. Deaths and complications were significantly greater in these groups. With an optimal decision threshold of 16.3 mg/L, CRP performed better (compared to the other tested blood biomarkers) with AUC, sensitivity and specificity of 94%, 88% and 99%, respectively. With the performance obtained from CRP in the diagnosis of neonatal bacterial infections, the installation of panels with other biomarkers with advanced and expensive technology is not necessary. Thus, optimal care and within a reasonable timeframe can be done in our health facilities, with this accessible marker that is CRP.

Quantitation of HIV-1 RNA in dried blood spots by the real-time NucliSENS EasyQ HIV-1 assay in Senegal.

Measurement of viral load in plasma remains the best marker for the follow-up of antiretroviral therapy. However, its use is limited in developing countries due to the lack of adequate facilities and equipment, and cryopreservation of plasma during storage and transportation. Practical and reliable methods adapted to field conditions for the collection, transportation and accurate measurement of HIV-1 viral load are needed for the optimum use of antiretroviral therapy in resource-limited countries. This study evaluated the use of dried blood spots (DBS) for the real-time quantitation of HIV-1 RNA levels with the NucliSENS EasyQ((R)) HIV-1 assay (bioMérieux, Lyon, France) under field conditions in Senegal (Africa). Dried blood spots and plasma from 41 patients living in suburban Dakar were used for determination of HIV-1 RNA concentrations and stability at 37 degrees C. Analysis was performed at the Dakar University Hospital laboratory. Extraction was done with the bioMérieux NucliSENS((R)) miniMAGtrade mark, and real-time detection was done with the bioMérieux NucliSENS((R)) EasyQ system. HIV-1 RNA concentrations in plasma were compared with concentrations in dried blood spots after 8 and 15 days at 37 degrees C. The study showed a strong concordance in RNA levels between plasma and dried blood spots, which appear to be very stable over time with no apparent degradation observed after 2 weeks at 37 degrees C (mean difference 0.065logIU/ml). These results suggest that the use of dried blood spots in combination with the NucliSENS EasyQ HIV-1 assay is well adapted for HIV-1 RNA level monitoring in centralized laboratories in developing countries.

Antiretroviral treatment outcome in HIV-1-infected patients routinely followed up in capital cities and remote areas of Senegal, Mali and Guinea-Conakry.

INTRODUCTION: Access to antiretroviral treatment (ART) becomes more and more effective in resource-limited settings (RLS). However, this global effort would be even more profitable if the access to laboratory services especially in decentralized settings was strengthened. We report the virological outcome and HIV-1 drug resistance in three West African countries using dried blood spots (DBS) samples. METHODS: We included HIV-1-infected adults on ART ≥6 months and followed up in capital cities and decentralized sites in Senegal, Mali and Guinea-Conakry. Patients were consecutively enrolled and DBS were collected in field conditions and kept at ambient temperature before transfer to the reference laboratory. Viral load (VL) was quantified using the NucliSENS EasyQ HIV-1 v1.2. Genotyping of HIV-1 pol gene was performed using in-house protocol. RESULTS: Of the 407 participants, 119, 152 and 136 were from Senegal, Mali and Guinea-Conakry, respectively. The median treatment duration was 36 months [IQR: 6-136]. Virological failure (VF) (VL≥3log10 copies/mL) was observed in 26% (95% confidence interval (CI), 18-35; n=31), 11% (95% CI, 6-17; n=16) and 24% (95% CI, 17-32; n=33) of patients in Senegal, Mali and Guinea-Conakry, respectively (p=0.001). Of samples presenting VL≥3log10 copies/mL (n=80), 70 were successfully genotyped. At least one drug resistance mutation (DRM) was detected in the following proportions: 70% (95% CI, 50-86; n=19), 93% (95% CI, 68-100; n=14) and 68% (95% CI, 48-84; n=19) in Senegal, Mali and Guinea-Conakry, respectively (p=0.22). Twenty-six per cent (26%; 95% CI, 16-38; n=18) of patients in VF harboured wild-type viruses, which is likely indicative of weak adherence. Phylogenetic analysis showed the predominance of CRF02_AG subtype (73%; 95% CI, 61-83; n=51). CONCLUSIONS: We describe the ART outcome in capital and rural settings of Senegal, Mali and Guinea-Conakry. Our results in all of the three countries highlight the need to reinforce the ART adherence in order to minimize the occurrence of drug resistance. In addition, these findings provide additional evidence that the use of DBS as a sampling support could assist virological monitoring of patients on ART in remote areas.

HIV type 1 subtype C remains the predominant subtype in men having sex with men in Senegal.

HIV-1 epidemics are expanding among men who have sex with men in low- and middle-income countries. To confirm and further explore preliminary data in Senegal, we aimed to determine 3 years after a first study the HIV-1 genetic diversity in three different viral regions. From 109 samples available in 2007, 93 were sequenced in gag, 77 in env, and 60 in pol. Phylogenetic analysis showed that subtype C predominated (38-52%), followed by CRF02_AG (30-40%), subtype B (13-17%), and CRF09_cpx (2.6-5%). Subsubtype A3 and strains tightly linked to CRF43_02G were identified in env and gag, respectively, and 12% of the samples were unique recombinants. Six transmission chains involving two to seven individuals were identified. Some strains carried resistance mutations inside transmission chains. This study confirmed the existence of a dual epidemic in Senegal and emphasized the need to strengthen prevention programs to avoid strains intermixing between low-risk women and high-risk men.

Surprisingly high prevalence of subtype C and specific HIV-1 subtype/CRF distribution in men having sex with men in Senegal.

BACKGROUND: Recent reports showed the high vulnerability for HIV infection of men who have sex with men (MSM) in Africa. Here, we report the HIV-1 variants that circulate among MSM in Senegal. METHODS: HIV-1 subtype/circulating recombinant form (CRF) was determined in an 1800-base pair fragment of pol for 70 HIV-1-positive samples from MSM. Phylogenetic trees were constructed using the neighbor-joining method with CLUSTALX. Similarity and bootstrap plots were then done for recombination analysis. The maximum likelihood approach was used for the identification of transmission clusters. RESULTS: Sixty-seven samples (95%) were from Senegalese MSM, 90% unmarried with a median age of 30 years. Fifty-five MSM had regular male partners, but 39 of 70 had also a regular female partner. The overall subtype/CRF distribution was as follows: 28 C (40%), 17 CRF02_AG (24.3%), 13 B (18.6%), 6 G (8.6%), 3 CRF09_cpx (4.3%), and 3 (4.3%) unique recombinants. In addition, 47 sequences (67.15%) were segregated into 15 transmission clusters. CONCLUSIONS: These variants circulate also among the general population or female sex workers, but the proportions are significantly different. Despite the massive stigma, the majority (80%) of MSM recognized having sex with women and could serve as a bridge for intermixing of HIV-1 variants between high-risk men and low-risk women.