Vaginal Carriage of Group B Streptococcus (GBS) in Pregnant Women, Antibiotic Sensitivity and Associated Risk Factors in Dakar, Senegal.

The eradication of neonatal Group B Streptococcus (GBS) infections, considered as a major public health priority, necessarily requires a mastery of the data on vaginal carriage in pregnant women. The aims of this study were to determine the prevalence of vaginal carriage of GBS in pregnant women, antibiotic susceptibility, and associated risk factors. This was a cross-sectional, descriptive study conducted over a period of 9 months (July 2020 to March 2021) in pregnant women between 34 and 38 weeks of gestation (WG) followed at the Nabil Choucair health center in Dakar. Identification and antibiotic susceptibility of GBS isolates were performed on the Vitek 2 from vaginal swabs cultured on Granada medium. Demographic and obstetric interview data were collected and analyzed on SPSS (version 25). The level of significance for all statistical tests was set at P < .05. The search of GBS vaginal carriage had involved 279 women aged 16 to 46 years, with a median pregnancy age of 34 (34-37) weeks' gestation. GBS was found in 43 women, for a vaginal carriage rate of 15.4%. In 27.9% (12/43) of volunteers screened, this carriage was monomicrobial, while in 72.1% (31/43) of women, GBS was associated with other pathogens such as Candida spp. (60.5%), Trichomonas vaginalis (2.3%), Gardnerella vaginalis (34.9%) and/or Mobiluncus spp. (11.6%). The level of resistance was 27.9% (12/43) for penicillin G, 53.5% (23/43) for erythromycin, 25.6% (11/43) for clindamycin and 100% for tetracycline. However, the strains had retained fully susceptible to vancomycin and teicoplanin. The main risk factor associated with maternal GBS carriage were ectocervical inflammation associated with contact bleeding (OR = 3.55; P = .005). The high rate of maternal vaginal GBS carriage and the levels of resistance to the various antibiotics tested confirm the importance of continuous GBS surveillance in our resource-limited countries.

First hepatitis E outbreak in Southeastern Senegal.

The Rapid proliferation of traditional gold mining sites in the Kedougou region has led to massive migration of people from neighbouring West African countries and the establishment of several small villages where poor hygiene and sanitation conditions exist. In this context, a Hepatitis E virus outbreak was reported in Kedougou in 2014 with several cases among the traditional mining workers. Herein, we described epidemiological and laboratory data collected during the outbreak's investigation from February 2012 to November 2014. Any suspected, contact or probable case was investigated, clinical and epidemiological data were collected. In our study, sera were collected and tested for viral RNA and anti-Hepatitis E virus (HEV) IgM. Archived serum samples from Kedougou were retrospectively screened by real-time polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). A total of 65 water samples collected from ponds and wells surrounding gold panners' sites and habitats and 75 tissues samples from rats captured in the environment of traditional gold mining sites were also tested. A total of 1617 sera were collected from 698 suspected cases, 862 contacts and 57 persons with missing information. The median age was 20 (1-88 years-old) and the sex ratio was 1.72. An overall rate of 64.62% (1045/1617) of these patients tested positive for HEV with a high case fatality rate in pregnant women. All water samples and animal tissues tested negative for HEV. Our data help not only determining of the beginning of the HEV outbreak to March 2012, but also identifying risk factors associated to its emergence. However, there is a need to implement routine diagnosis, surveillance and training of health personnel in order to reduce mortality especially among pregnant women. In addition, further studies are needed to identify the virus reservoir and environmental risk factors for HEV in the Kedougou region.

Performance of Xpert HIV-1 viral load test in Senegal: a country of high circulation of CRF02_AG.

Introduction: the introduction of the point-of-care in HIV-1 viral load quantification appears to be a complementary strategy to the existing conventional system of the acceleration plan for the achievement of the three 90s in Senegal. The objective of this study was to evaluate the performance of the Xpert® HIV-1 viral load in the context of circulation of non-B, non-C subtypes. Methods: two hundred samples, were tested on Xpert® HIV-1 Viral Load using 1 ml of plasma in comparison to 600 µl on Abbott Real-time HIV-1 assay. The difference between viral load values was considered significant for Dlog <0.5 log copies/ml. Results: a good correlation (r=0.985) was noted and confirmed using passing-bablok regression (slope 1.048; 95% CI: 1.036 to 1.069) for 188 samples with samples. A mean difference of 0.0075 log10 copies/ml for a 95% confidence interval (CI) of 0.002 log10 copies/ml to 0.013 log10 copies/ml was obtained. Sensitivity and specificity were respectively 93.6% and 93.5% at the threshold of 1.6 log10 copies/ml and 100% and 99% at the threshold of 3.0 log10 copies/ml. Conclusion: these results show that Xpert® HIV-1 Viral Load has excellent performance. In Senegal, and can be used for HIV viral load monitoring.

Detection and quantitation of hepatitis B surface antigen (HBsAg) on dried blood spots: a solution for easy access for hepatitis B diagnosis and elimination in remote areas.

Hepatitis B virus (HBV) is generally endemic in resource-limited countries, which are characterized by a deficit of technical facilities that could delay diagnosis and treatment. To facilitate the accessibility to diagnostic and connection to treatment, evaluation, and promotion of alternatives and/or simplified strategies and inexpensive tools such as dried blood specimens need to be investigated and implemented. This study aimed to evaluate dried blood spots (DBS) for the detection and quantification of HBsAg. This study included 100 DBS from subjects tested positive for HBsAg, and 50 DBSs from subjects tested negative for HBsAg by the automate Architect i1000sr (Abbott Diagnostics, Ireland). Hepatitis B surface antigen detection was performed with determine HBsAg Alere® tests (Alere International Limited, Ireland) and Architect® HBsAg Qualitative II Assays (Abbott, Diagnostics, Ireland) after 15 and 30 days (D15, D30). For HBsAg-positive subjects, the quantification of HBsAg was performed at day zero (D0) from plasma and at D15 and D30 from the DBSs. At D15, the sensitivity and specificity were 96% and 100% for the Determine® tests and 100% and 100% for the Architect® tests, respectively. At D30, the sensitivity and specificity were 96% and 100% for the Determine® tests and 100% and 100% for the Architect® tests, respectively. For HBsAg quantification, the agreement rates were 96%, 96% and 100% between D0-D15, D0-D30 and D15-D30, respectively. This work showed that DBSs can be very useful for HBsAg detection and quantification and therefore in the management of HBV infection in resource-limited settings.

Biological Investigation of Amaryllidaceae Alkaloid Extracts from the Bulbs of Pancratium trianthum Collected in the Senegalese Flora.

Amaryllidaceae plants are rich in alkaloids with biological properties. Pancratium trianthum is an Amaryllidaceae species widely used in African folk medicine to treat several diseases such as central nervous system disorders, tumors, and microbial infections, and it is used to heal wounds. The current investigation explored the biological properties of alkaloid extracts from bulbs of P. trianthum collected in the Senegalese flora. Alkaloid extracts were analyzed and identified by chromatography and mass spectrometry. Alkaloid extracts from P. trianthum displayed pleiotropic biological properties. Cytotoxic activity of the extracts was determined on hepatocarcinoma Huh7 cells and on acute monocytic leukemia THP-1 cells, while agar diffusion and microdilution assays were used to evaluate antibacterial activity. Antiviral activity was measured by infection of extract-treated cells with dengue virus (DENVGFP) and human immunodeficiency virus-1 (HIV-1GFP) reporter vectors. Cytotoxicity and viral inhibition were the most striking of P. trianthum's extract activities. Importantly, non-cytotoxic concentrations were highly effective in completely preventing DENVGFP replication and in reducing pseudotyped HIV-1GFP infection levels. Our results show that P. trianthum is a rich source of molecules for the potential discovery of new treatments against various diseases. Herein, we provide scientific evidence to rationalize the traditional uses of P. trianthum for wound treatment as an anti-dermatosis and antiseptic agent.

Low Circulation of Subclade A1 Enterovirus D68 Strains in Senegal during 2014 North America Outbreak.

To retrospectively investigate enterovirus D68 circulation in Senegal during the 2014 US outbreak, we retrieved specimens from 708 persons, mostly children, who had acute respiratory symptoms during September-December 2014. Enterovirus D68 was detected in 14 children (2.1%); most cases occurred in October. Phylogenetic analysis revealed that all strains clustered within subclade A1.

Effectiveness of the prevention of HIV mother -to-child transmission (PMTCT) program via early infant diagnosis (EID) data in Senegal.

BACKGROUND: To improve the care and treatment of HIV-exposed children, early infant diagnosis (EID) using dried blood spot (DBS) sampling has been performed in Senegal since 2007, making molecular diagnosis accessible for patients living in decentralized settings. This study aimed to determine the evolution of the HIV transmission rate in children from 2008 to 2015 and to analyze associated factors, particularly the mother's treatment status and/or child's prophylaxis status and the feeding mode. METHODS: The data were analyzed using EID reports from the reference laboratory. Information related to sociodemographic characteristics, HIV profiles, the mother's treatment status, the child's prophylaxis status, and the feeding mode was included. Descriptive statistics were calculated, and bivariate and multivariate logistic regression analyses were performed. RESULTS: During the study period, a total of 5418 samples (5020 DBS and 398 buffy coat) from 168 primary prevention of HIV mother-to-child transmission (PMTCT) intervention sites in Senegal were tested. The samples were collected from 4443 children with a median age of 8 weeks (1-140 weeks) and a sex ratio (M/F) of 1.1 (2309/2095). One-third (35.2%; N = 1564) of the children were tested before 6 weeks of age. Twenty percent (N = 885) underwent molecular diagnostic testing more than once. An increased number of mothers receiving treatment (57.4%; N = 2550) and children receiving prophylaxis (52.1%; N = 2315) for protection against HIV infection during breastfeeding was found over the study period. The transmission rate decreased from 14.8% (95% confidence interval (CI): 11.4-18.3) in 2008 to 4.1% (95% CI: 2.5-7.5) in 2015 (p < 0.001). However, multivariate logistic regression analysis revealed that independent predictors of HIV mother-to-child transmission included lack of mother's treatment (adjusted odd ratio (aOR) = 3.8, 95% CI: 1.9-7.7; p˂0.001), lack of child's prophylaxis (aOR = 7.8, 95% CI: 1.7-35.7; p = 0.009), infant age at diagnosis (aOR = 2.2, 95% CI: 1.1-4.3 for ≤6 weeks versus 12-24 weeks; p = 0.025) and protective effect of breastfeeding on ART against formula feeding (aOR = 0.4, 95% CI: 0.2, 0.7; p = 0.005). CONCLUSION: This study demonstrates the effectiveness of PMTCT interventions in Senegal but indicates also that increased efforts should be continued to reduce the MTCT rate to less than 2%.

Confirmed Case of Buruli Ulcer, Senegal, 2018.

Buruli ulcer is a necrotizing skin disease caused by Mycobacterium ulcerans and is usually associated with tropical climates and exposure to slow-moving or stagnant water. We report a case of Buruli ulcer that may have originated in an urban semiarid area of Senegal.

Chemical Diversity and Antimicrobial Activity of Volatile Compounds from Zanthoxylum zanthoxyloides Lam. according to Compound Classes, Plant Organs and Senegalese Sample Locations.

The chemical diversity of Zanthoxylum zanthoxyloides growing wild in Senegal was studied according to volatile compound classes, plant organs and sample locations. The composition of fruit essential oil was investigated using an original targeted approach based on the combination of gas chromatography (GC) and liquid chromatography (LC) both coupled with mass spectrometry (MS). The volatile composition of Z. zanthoxyloides fruits exhibited relative high amounts of hydrocarbon monoterpenes (24.3 - 55.8%) and non-terpenic oxygenated compounds (34.5 - 63.1%). The main components were (E)-ß-ocimene (12.1 - 39%), octyl acetate (11.6 - 21.8%) and decanol (9.7 - 15.4%). The GC and GC/MS profiling of fruit essential oils showed a chemical variability according to geographical locations of plant material. The LC/MS/MS analysis of fruit oils allowed the detection of seven coumarins in trace content. The chemical composition of fruit essential oils was compared with volatile fractions of leaves and barks (root and trunk) from the same plant station. Hexadecanoic acid, germacrene D and decanal were identified as the major constituents of leaves whereas the barks (root and trunk) were dominated by pellitorine (85.8% and 57%, respectively), an atypic linear compound with amide group. The fruit essential oil exhibited interesting antimicrobial activities against Staphylococcus aureus and Candida albicans, particularly the alcohol fraction of the oil.

Validation of a structural comparison of the antigenic characteristics of Usutu virus and West Nile virus envelope proteins.

Cross-reactions observed in serological assays between Usutu virus (USUV), the USUV outlier subtype strain CAR_1969 and West Nile virus (WNV) suggest that they share antigenic features amongst their structural outer proteins especially envelope (E) proteins. To investigate the molecular background of this observation, we compared the E protein sequences of seven USUV strains, USUV subtype strain CAR_1969 and WNV strain 2471, focusing on the binding site defined by the WNV neutralizing antibody E16. USUV SouthAfrica_1959 differs from WNV 2741 in three of four residues critical for E16 antibody binding and five of the 12 additionally involved residues. In contrast, USUV subtype CAR_1969 differs from WNV 2741 in two critical residues and five additional residues. Furthermore, USUV subtype CAR_1969 differs from other USUV strains in two critical residues. E16 antibody binding has previously been shown to be highly specific for WNV; thus, the observed variation in amino acid residues suggests that the region corresponding to the WNV E16 epitope is probably not responsible for the observed cross-reactions between WNV and USUV. Seroneutralisation assays confirmed these findings for WNV and USUV, however, showed occurring cross-reactivity between WNV and USUV subtype CAR_1969 at high antibody titers. The sequence diversity in this region might also explain some of the observed different antigenic characteristics of USUV strains and USUV subtype CAR_1969. A therapeutic effect of E16 antibody has been described in WNV infected mice; therefore, a USUV specific antibody generated against the region corresponding to the WNV E16 binding site might represent an approach for treating USUV infections.

Human papillomavirus infection in women in four regions of Senegal.

Cervical cancer is the most frequent cancer among women in Senegal. However, there are few data concerning the human papillomavirus (HPV) types inducing neoplasia and cervical cancers and their prevalence in the general population of Senegal. The aim of this study is to determine the prevalence of HPV infection in Senegalese women aged 18 years and older in Dakar Region and three other regions. Cervical samples were collected from 498 women aged 18-80 years (mean, 42.1 years) in Dakar Region. Also, 438 samples were collected from three other regions: Thiès, Saint-Louis, and Louga. The samples were screened for 21 HPV genotypes using an HPV type-specific E7 PCR bead-based multiplex genotyping assay (TS-MPG). The prevalence of high risk (HR)-HPV in Dakar Region was 17.4%. HPV 52 (3.2%) was the most prevalent HPV type, followed by HPV 31 (3.0%) and HPV 16, 45, and 53 (all 2.8%). In the Thiès, Saint-Louis, and Louga Regions, the prevalence of HR-HPV was 23.2%, 13.1%, and 19.4%, respectively. The study revealed the specificity of HPV prevalence in Dakar Region and other regions of Senegal. The observed patterns show some differences compared with other regions of the world. These findings raise the possibility that, in addition to HPV 16 and HPV 18, other HPV types should be considered for a vaccination program in Senegal. However, additional studies to determine the HPV type distribution in cervical cancer specimens in Senegal are required to further corroborate this hypothesis.

Antibiotic susceptibility of streptococcus pyogenes isolated from respiratory tract infections in dakar, senegal.

Group A Streptococcus (GAS) is one of the major causes of respiratory tract infections. The objectives of this study were to identify isolates of S. pyogenes obtained from respiratory tract infections, and to assess their susceptibility to several antibiotics. A total of 40 strains were isolated and their susceptibility to 17 antibiotics was tested using a standard disk diffusion method. The minimum inhibitory concentrations (MICs) were determined using the E-test. All isolates were sensitive to ß-lactam antibiotics including penicillin, amoxicillin, and cephalosporins. Macrolides remain active with the exception of spiramycin, which showed reduced susceptibility. Out of the 40 isolates, 100% of the isolates were resistant to tetracycline. Interestingly, isolates were sensitive to chloramphenicol, teicoplanin, vancomycine, and levofloxacin, providing potential alternative choices of treatment against infections with S. pyogenes.

Usutu virus in Africa.

Usutu virus (USUV) was discovered in South Africa in 1959. Since then, it has been reported in several African countries including Senegal, Central African Republic, Nigeria, Uganda, Burkina Faso, Cote d'Ivoire, and Morocco. In 2001, USUV has been identified for the first time outside of Africa, namely in Europe, where it caused a significant mortality among blackbirds in Vienna, Austria. In 2009, the first two human cases of USUV infection in Europe have been reported in Italy, causing encephalitis in immunocompromised patients. The host range in Africa includes mainly Culex mosquitoes, birds, and also humans with one benign and one severe case. Given its role as a potential human pathogen and the similar appearance compared with other emerging arboviruses, it is essential to investigate the natural history and ecology of USUV in Africa. In this regard, we review the emergence of USUV in Africa, summarizing data about isolations, host range, and potential vectors, which should help to improve our understanding of the factors underlying the circulation of USUV in Europe and Africa.

Antibiotic susceptibility of Helicobacter pylori isolates in Dakar, Senegal.

BACKGROUND: Helicobacter pylori is the primary cause of peptic ulcer disease and an etiologic agent in the development of gastric cancer. A high frequency of H. pylori infection has been reported from resource-poor regions. H. pylori infection is curable with regimens of multiple antimicrobial agents. However, antibiotic resistance is a leading cause of treatment failure. In Africa, there are very little data concerning the susceptibility of H. pylori isolates to antibiotics. METHODOLOGY: H. pylori isolates from gastric biopsies from outpatients > or = 18 years old affected by a gastro-duodenal ulcer were used in this study. Susceptibility testing was performed for amoxicillin, ciprofloxacin and metronidazole by using the Epsilometer test (E-test) method. RESULTS: H. pylori strains were isolated from 40 patients of whom 36 were diagnosed as having duodenal ulcer, two with gastric ulcer, and two with gastro-duodenal ulcer. Thirty-six (90%) of the isolates were resistant to metronidazole (MICs > or = 8 microg/l), whereas all isolates were susceptible to amoxicillin (MICs < or = 0.5 microg/ml) and ciprofloxacin (MICs < or = 1 microg/ml). CONCLUSION: These data suggest that metronidazole should not be used therapeutically among Senegalese patients in first-line therapy, while ciprofloxacin could be recommended in association with amoxicillin and a proton pump inhibitor in Senegal.

Analysis of topoisomerase mutations in fluoroquinolone-resistant and -susceptible Campylobacter jejuni strains isolated in Senegal.

In this study, topoisomerase mutations in ciprofloxacin-resistant and -susceptible Campylobacter jejuni were analysed by DNA sequencing. In certain ciprofloxacin-resistant C. jejuni, the mechanism of resistance was complex. The Thr86-Ala substitution in the GyrA protein appears to play a role in increasing the minimum inhibitory concentration of nalidixic acid only. In addition, isolates with this amino acid change and those resistant to quinolones but lacking a mutation in the GyrA quinolone resistance-determining region could be derived from two different clones. Based on gyrA and gyrB polymorphisms, C. jejuni isolates from the Dakar region of Senegal appeared to be less diverse than those from other countries. Moreover, C. jejuni isolates in Senegal appeared to differ from European isolates by lack of a silent mutation at codon 120 of the gyrA gene.

Genotypic characterization of antibiotic-resistant Salmonella enteritidis isolates in Dakar, Senegal.

BACKGROUND: It is well established that Salmonella enterica is a major cause of food-borne disease worldwide. In Africa, according to the Who Global Salm-Surv country data bank from 2000 to 2002 Salmonella enterica serovar Enteritidis was the most common serotype involved in human salmonellosis. In Dakar this serotype of Salmonella has been reported as a frequent and an increasing cause of human infection. METHODOLOGY: The genetic determinants of the antimicrobial resistance of 25 selected multiresistant strains of Salmonella enterica serovar Enteritidis referred to the National Reference Center for Enterobacteria (NRCE) in Dakar were investigated using molecular techniques. RESULTS: All strains carried blaTEM 1 genes. Five harboured three types of class 1 integrons with gene cassettes dfrA15, dfrA1-aadA1 and dfrA7. Multiresistance was due to a 23 Kb conjugative plasmid. DNA fingerprinting by macrorestriction of genomic DNA revealed a single related group suggesting that strains might be clonal. CONCLUSIONS: The spread of resistance genes through plasmid transfer plays an important role in the dissemination of antibiotic resistance in enteric pathogens such as Salmonella Enteritidis; the risk of transmissibility of antibiotic resistance between different bacterial strains highlights the urgent need to develop strategies to limit the spread of antimicrobial resistance among bacterial enteropathogens.

Genetic diversity and quinolone resistance in Campylobacter jejuni isolates from poultry in Senegal.

We used the multilocus sequence typing (MLST) method to evaluate the genetic diversity of 46 Campylobacter jejuni isolates from chickens and to determine the link between quinolone resistance and sequence type (ST). There were a total of 16 ST genotypes, and the majority of them belonged to seven clonal complexes previously identified by using isolates from human disease. The ST-353 complex was the most common complex, whereas the ST-21, ST-42, ST-52, and ST-257 complexes were less well represented. The resistance phenotype varied for each ST, and the Thr-86-Ile substitution in the GyrA protein was the predominant mechanism of resistance to quinolone. Nine of the 14 isolates having the Thr-86-Ile substitution belonged to the ST-353 complex. MLST showed that the emergence of quinolone resistance is not related to the diffusion of a unique clone and that there is no link between ST genotype and quinolone resistance. Based on silent mutations, different variants of the gyrA gene were shown to exist for the same ST. These data provide useful information for understanding the epidemiology of C. jejuni in Senegal.