Bacterial vaginosis and other infections in pregnant women in Senegal.

BACKGROUND: Bacterial vaginosis (BV) is associated with a higher risk of preterm delivery and spontaneous abortion. Yet little data on BV prevalence exist for sub-Saharan countries. The aim of this study was to estimate the prevalence of bacterial vaginosis and associated risk factors among pregnant women in Senegal. METHODS: From October 2013 to December 2018, pregnant women in their third trimester were recruited in two primary health centers (one suburban, one rural) in Senegal. Healthcare workers interviewed women and collected a lower vaginal swab and a blood sample. Vaginal flora were classified into four categories using vaginal smear microscopic examination and Gram's coloration. In our study, BV was defined as vaginal flora with no Lactobacillus spp. Variables associated with BV were analyzed using STATA® through univariate and multivariate analysis. RESULTS: A total of 457 women provided a vaginal sample for analysis. Overall, BV prevalence was 18.6% (85/457) [95% CI 15.4-22.6]) and was similar in suburban and rural areas (18.9% versus 18.1%, p = 0.843). Multivariate analysis showed that primigravidity was the only factor independently associated with a lower risk of BV (aOR 0.35 [95% CI 0.17-0.72]). CONCLUSIONS: Our study showed significant BV prevalence among pregnant women in Senegal. Although the literature has underscored the potential consequences of BV for obstetric outcomes, data are scarce on BV prevalence in sub-Saharan African countries. Before authorities consider systematic BV screening for pregnant women, a larger study would be useful in documenting prevalence, risk factors and the impact of BV on pregnancy outcomes.

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.

Baseline Ex Vivo and Molecular Responses of Plasmodium falciparum Isolates to Piperaquine before Implementation of Dihydroartemisinin-Piperaquine in Senegal.

Dihydroartemisinin-piperaquine, which was registered in 2017 in Senegal, is not currently used as the first-line treatment against uncomplicated malaria. A total of 6.6% to 17.1% of P. falciparum isolates collected in Dakar in 2013 to 2015 showed ex vivo-reduced susceptibility to piperaquine. Neither the exonuclease E415G mutation nor the copy number variation of the plasmepsin II gene (Pfpm2), associated with piperaquine resistance in Cambodia, was detected in Senegalese parasites.

Low polymorphisms in pfact, pfugt and pfcarl genes in African Plasmodium falciparum isolates and absence of association with susceptibility to common anti-malarial drugs.

BACKGROUND: Resistance to all available anti-malarial drugs has emerged and spread including artemisinin derivatives and their partner drugs. Several genes involved in artemisinin and partner drugs resistance, such as pfcrt, pfmdr1, pfK13 or pfpm2, have been identified. However, these genes do not properly explain anti-malarial drug resistance, and more particularly clinical failures observed in Africa. Mutations in genes encoding for Plasmodium falciparum proteins, such as P. falciparum Acetyl-CoA transporter (PfACT), P. falciparum UDP-galactose transporter (PfUGT) and P. falciparum cyclic amine resistance locus (PfCARL) have recently been associated to resistance to imidazolopiperazines and other unrelated drugs. METHODS: Mutations on pfugt, pfact and pfcarl were characterized on 86 isolates collected in Dakar, Senegal and 173 samples collected from patients hospitalized in France after a travel in African countries from 2015 and 2016 to assess their potential association with ex vivo susceptibility to chloroquine, quinine, lumefantrine, monodesethylamodiaquine, mefloquine, dihydroartemisinin, artesunate, doxycycline, pyronaridine and piperaquine. RESULTS: No mutations were found on the genes pfugt and pfact. None of the pfcarl described mutations were identified in these samples from Africa. The K784N mutation was found in one sample and the K734M mutation was identified on 7.9% of all samples for pfcarl. The only significant differences in ex vivo susceptibility according to the K734M mutation were observed for pyronaridine for African isolates from imported malaria and for doxycycline for Senegalese parasites. CONCLUSION: No evidence was found of involvement of these genes in reduced susceptibility to standard anti-malarial drugs in African P. falciparum isolates.

Antimicrobial Resistance Profile of Salmonella Isolates in Chicken Carcasses in Dakar, Senegal.

The incidence of the Salmonella contamination of poultry products in Senegal is unknown. Salmonella contamination and antimicrobial drug resistance profiles in chicken carcasses were investigated. Between July 2012 and July 2013, three types of chicken carcasses (broilers, laying hens, and premises chickens) obtained from retailers in the markets of Dakar and its suburbs were tested for Salmonella contamination. Salmonella strains were isolated from 300 chicken carcasses according to International Organization for Standardization ISO 6579 (2002) guidelines. In these samples, 273 isolates were obtained, belonging to 22 serovars, and 53% samples were contaminated with at least 1 serovar. Standardized techniques were used for the susceptibility testing and serotyping of isolates. Hygiene conditions, in terms of the cleanliness of stalls, the packing of chicken carcasses in bags, and the maintenance of the cold chain at the stall, were moderately poor. The three serovars most frequently identified were Salmonella Istanbul (28%), Salmonella Brancaster (19%), and Salmonella Kentucky (13%). Overall, 21% of isolates were resistant to quinolones and fluoroquinolones. Serovar Istanbul was resistant to tetracycline (TE) and trimethoprim + sulfamethoxazole (SXT). Serovars Brancaster and Kentucky were resistant to betalactams and to quinolones or fluoroquinolones. The uncommon serovar Senftenberg had the strongest resistance profile, displaying resistance to betalactams including imipenem (IMP). Large numbers of isolates were resistant to TE (66%) and SXT (47%). Resistance to cephalosporins (5%), chloramphenicol (2%), gentamicin (8%), and IMP (1%) was less frequent. A large proportion of the broilers sold in Dakar markets were contaminated with Salmonella. This situation probably resulted from poor hygiene conditions in chicken farms and slaughterhouses and from breaks in the cold chain at some point in the distribution of poultry products.

Confirmation of Plasmodium falciparum in vitro resistance to monodesethylamodiaquine and chloroquine in Dakar, Senegal, in 2015.

BACKGROUND: In response to increasing resistance to anti-malarial drugs, Senegal adopted artemisinin-based combination therapy (ACT) as the first-line treatment for uncomplicated malaria in 2006. However, resistance of Plasmodium falciparum parasites to artemisinin derivatives, characterized by delayed parasite clearance after treatment with ACT or artesunate monotherapy, has recently emerged and rapidly spread in Southeast Asia. After 10 years of stability with rates ranging from 5.6 to 11.8%, the prevalence of parasites with reduced susceptibility in vitro to monodesethylamodiaquine, the active metabolite of an ACT partner drug, increased to 30.6% in 2014 in Dakar. Additionally, after a decrease of the in vitro chloroquine resistance in Dakar in 2009-2011, the prevalence of parasites that showed in vitro chloroquine resistance increased again to approximately 50% in Dakar since 2013. The aim of this study was to follow the evolution of the susceptibility to ACT partners and other anti-malarial drugs in 2015 in Dakar. An in vitro test is the only method currently available to provide an early indication of resistance to ACT partners. RESULTS: Thirty-two P. falciparum isolates collected in 2015 in Dakar were analysed using a standard ex vivo assay based on an HRP2 ELISA. The prevalence of P. falciparum parasites with reduced susceptibility in vitro to monodesethylamodiaquine, chloroquine, mefloquine, doxycycline and quinine was 28.1, 46.9, 45.2, 31.2 and 9.7%, respectively. None of the parasites were resistant to lumefantrine, piperaquine, pyronaridine, dihydroartemisinin and artesunate. These results confirm an increase in the reduced susceptibility to monodesethylamodiaquine observed in 2014 in Dakar and the chloroquine resistance observed in 2013. The in vitro resistance seems to be established in Dakar. Additionally, the prevalence of parasites with reduced susceptibility to doxycycline has increased two-fold compared to 2014. CONCLUSIONS: The establishment of a reduced susceptibility to monodesethylamodiaquine as well as chloroquine resistance, and the emergence of a reduced susceptibility to doxycycline are disturbing. The in vitro and in vivo surveillance of anti-malarial drugs must be implemented in Senegal.

High third-generation cephalosporin resistant Enterobacteriaceae prevalence rate among neonatal infections in Dakar, Senegal.

BACKGROUND: Neonatal infection constitutes one of Senegal's most important public health problems, with a mortality rate of 41 deaths per 1,000 live births. METHODS: Between January 2007 and March 2008, 242 neonates with suspected infection were recruited at three neonatal intensive care units in three major tertiary care centers in Dakar, the capital of Senegal. Neonatal infections were confirmed by positive bacterial blood or cerebrospinal fluid culture. The microbiological pattern of neonatal infections and the antibiotic susceptibility of the isolates were characterized. In addition, the genetic basis for antibiotic resistance and the genetic background of third-generation cephalosporin-resistant (3GC-R) Enterobacteriaceae were studied. RESULTS: A bacteriological infection was confirmed in 36.4 % (88/242) of neonates: 22.7 % (30/132) during the early-onset and 52.7 % (58/110) during the late-onset periods (p > 0.20). Group B streptococci accounted for 6.8 % of the 88 collected bacterial isolates, while most of them were Enterobacteriaceae (n = 69, 78.4 %). Of these, 55/69 (79.7 %) were 3GC-R. The bla CTX-M-15 allele, the bla SHV and the bla TEM were highly prevalent (63.5, 65.4 and 53.8 %, respectively), usually associated with qnr genes (65.4 %). Clonally related strains of 3GC-R Klebsiella pneumoniae and 3GC-R Enterobacter cloacae, the two most commonly recovered 3GC-R Enterobacteriaceae (48/55), were detected at the three hospitals, underlining the role of cross-transmission in their spread. The overall case fatality rate was 18.6 %. CONCLUSIONS: Measures should be taken to prevent nosocomial infections and the selection of resistant bacteria.

Multidrug-resistant Salmonella enterica serotype Typhi, Gulf of Guinea Region, Africa.

We identified 3 lineages among multidrug-resistant (MDR) Salmonella enterica serotype Typhi isolates in the Gulf of Guinea region in Africa during the 2000s. However, the MDR H58 haplotype, which predominates in southern Asia and Kenya, was not identified. MDR quinolone-susceptible isolates contained a 190-kb incHI1 pST2 plasmid or a 50-kb incN pST3 plasmid.

Role of Pfmdr1 in in vitro Plasmodium falciparum susceptibility to chloroquine, quinine, monodesethylamodiaquine, mefloquine, lumefantrine, and dihydroartemisinin.

The involvement of Pfmdr1 (Plasmodium falciparum multidrug resistance 1) polymorphisms in antimalarial drug resistance is still debated. Here, we evaluate the association between polymorphisms in Pfmdr1 (N86Y, Y184F, S1034C, N1042D, and D1246Y) and Pfcrt (K76T) and in vitro responses to chloroquine (CQ), mefloquine (MQ), lumefantrine (LMF), quinine (QN), monodesethylamodiaquine (MDAQ), and dihydroartemisinin (DHA) in 174 Plasmodium falciparum isolates from Dakar, Senegal. The Pfmdr1 86Y mutation was identified in 14.9% of the samples, and the 184F mutation was identified in 71.8% of the isolates. No 1034C, 1042N, or 1246Y mutations were detected. The Pfmdr1 86Y mutation was significantly associated with increased susceptibility to MDAQ (P = 0.0023), LMF (P = 0.0001), DHA (P = 0.0387), and MQ (P = 0.00002). The N86Y mutation was not associated with CQ (P = 0.214) or QN (P = 0.287) responses. The Pfmdr1 184F mutation was not associated with various susceptibility responses to the 6 antimalarial drugs (P = 0.168 for CQ, 0.778 for MDAQ, 0.324 for LMF, 0.961 for DHA, 0.084 for QN, and 0.298 for MQ). The Pfmdr1 86Y-Y184 haplotype was significantly associated with increased susceptibility to MDAQ (P = 0.0136), LMF (P = 0.0019), and MQ (P = 0.0001). The additional Pfmdr1 86Y mutation increased significantly the in vitro susceptibility to MDAQ (P < 0.0001), LMF (P < 0.0001), MQ (P < 0.0001), and QN (P = 0.0026) in wild-type Pfcrt K76 parasites. The additional Pfmdr1 86Y mutation significantly increased the in vitro susceptibility to CQ (P = 0.0179) in Pfcrt 76T CQ-resistant parasites.

Plasmodium falciparum susceptibility to anti-malarial drugs in Dakar, Senegal, in 2010: an ex vivo and drug resistance molecular markers study.

BACKGROUND: In 2006, the Senegalese National Malaria Control Programme recommended artemisinin-based combination therapy (ACT) as the first-line treatment for uncomplicated malaria. Since the introduction of ACT, there have been very few reports on the level of resistance of P. falciparum to anti-malarial drugs. To determine whether parasite susceptibility has been affected by the new anti-malarial policies, an ex vivo susceptibility and drug resistance molecular marker study was conducted on local isolates obtained from the Centre de santé Elizabeth Diouf (Médina, Dakar, Senegal). METHODS: The prevalence of genetic polymorphisms in genes associated with anti-malarial drug resistance, i.e., pfcrt, pfdhfr, pfdhps and pfmdr1, were evaluated for a panel of 165 isolates collected from patients recruited from 17 August 2010 to 6 January 2011. The malaria isolates were assessed for susceptibility to chloroquine (CQ); quinine (QN); monodesethylamodiaquine (MDAQ), the active metabolite of amodiaquine; mefloquine (MQ); lumefantrine (LMF); dihydroartemisinin (DHA), the active metabolite of artemisinin derivatives; and doxycycline (DOX) using the Plasmodium lactate dehydrogenase (pLDH) ELISA. RESULTS: The prevalence of the in vitro resistant isolates, or isolates with reduced susceptibility, was 62.1% for MQ, 24.2% for CQ, 10.3% for DOX, 11.8% MDAQ, 9.7% for QN, 2.9% for LMF and 0% for DHA. The Pfcrt 76T mutation was identified in 43.6% of the samples. The pfmdr1 86Y, 184F and 1246Y mutations were found in 16.2%, 50.0% and 1.6% of the samples, respectively. The pfdhfr 108N, 51I and 59R mutations were identified in 81.9%, 77.4% and 79.4% of the samples, respectively. The double mutant (108N and 51I) was detected in 75.5% of the isolates, and the triple mutant (108N, 51I and 59R) was detected in 73.6% of the isolates. The pfdhps 437G, 436A and 613S mutations were found in 54.4%, 38.6% and 1.2% of the samples, respectively. There was only one double mutant, 437G and 540E, and one quintuple mutant, pfdhfr 108N, 51I and 59R and pfdhps 437G and 540E. The prevalence of the quadruple mutant (pfdhfr 108N, 51I and 59R and pfdhps 437G) was 36.7%. CONCLUSIONS: The results of this study indicate that an intensive surveillance of the in vitro P. falciparum susceptibility to anti-malarial drugs must be conducted in Senegal.

Pfhrp2 and pfhrp3 polymorphisms in Plasmodium falciparum isolates from Dakar, Senegal: impact on rapid malaria diagnostic tests.

BACKGROUND: An accurate diagnosis is essential for the rapid and appropriate treatment of malaria. The accuracy of the histidine-rich protein 2 (PfHRP2)-based rapid diagnostic test (RDT) Palutop+4® was assessed here. One possible factor contributing to the failure to detect malaria by this test is the diversity of the parasite PfHRP2 antigens. METHODS: PfHRP2 detection with the Palutop+4® RDT was carried out. The pfhrp2 and pfhrp3 genes were amplified and sequenced from 136 isolates of Plasmodium falciparum that were collected in Dakar, Senegal from 2009 to 2011. The DNA sequences were determined and statistical analyses of the variation observed between these two genes were conducted. The potential impact of PfHRP2 and PfHRP3 sequence variation on malaria diagnosis was examined. RESULTS: Seven P. falciparum isolates (5.9% of the total isolates, regardless of the parasitaemia; 10.7% of the isolates with parasitaemia ≤0.005% or ≤250 parasites/µl) were undetected by the PfHRP2 Palutop+4® RDT. Low parasite density is not sufficient to explain the PfHRP2 detection failure. Three of these seven samples showed pfhrp2 deletion (2.4%). The pfhrp3 gene was deleted in 12.8%. Of the 122 PfHRP2 sequences, 120 unique sequences were identified. Of the 109 PfHRP3 sequences, 64 unique sequences were identified. Using the Baker's regression model, at least 7.4% of the P. falciparum isolates in Dakar were likely to be undetected by PfHRP2 at a parasite density of ≤250 parasites/µl (slightly lower than the evaluated prevalence of 10.7%). This predictive prevalence increased significantly between 2009 and 2011 (P = 0.0046). CONCLUSION: In the present work, 10.7% of the isolates with a parasitaemia ≤0.005% (≤250 parasites/µl) were undetected by the PfHRP2 Palutop+4® RDT (7.4% by the predictive Baker'model). In addition, all of the parasites with pfhrp2 deletion (2.4% of the total samples) and 2.1% of the parasites with parasitaemia >0.005% and presence of pfhrp2 were not detected by PfHRP2 RDT. PfHRP2 is highly polymorphic in Senegal. Efforts should be made to more accurately determine the prevalence of non-sensitive parasites to pfHRP2.

In vitro susceptibility to quinine and microsatellite variations of the Plasmodium falciparum Na+/H+ exchanger transporter (Pfnhe-1) gene in 393 isolates from Dakar, Senegal.

BACKGROUND: Although the World Health Organization recommends replacing quinine (QN) by artesunate due to its increased efficacy and the higher tolerance to the drug in both adults and children, QN remains a first-line treatment for severe malaria, especially in Africa. Investigations of microsatellite Pfnhe-1 ms4760 polymorphisms in culture-adapted isolates from around the world have revealed that an increase in the number of DNNND amino acid motifs was associated with decreased QN susceptibility, whereas an increase in the number of DDNHNDNHNND motifs was associated with increased QN susceptibility. METHODS: In this context, to further analyse associations between Pfnhe-1 ms4760 polymorphisms and QN susceptibility, 393 isolates freshly collected between October 2009 and January 2010 and July 2010 and February 2011, respectively, at the Hôpital Principal de Dakar, Senegal were assessed ex vivo for QN susceptibility, and their genes were amplified and sequenced. RESULTS: Of the 393 Plasmodium falciparum clinical isolates collected, 145 were successfully cultured. The 145 QN IC50s ranged from 2.1 to 1291 nM, and 17 isolates (11.7%) exceed the QN reduced susceptibility threshold of 611 nM. Among the 393 P. falciparum clinical isolates, 47 different alleles were observed. The three most prevalent profiles were ms4760-1 (no = 72; 18.3%), ms4760-3 (no = 65; 16.5%) and ms4760-7 (no = 40; 10.2%). There were no significant associations observed between QN IC50 values and i) the number of repeats of DNNND in block II (p = 0.0955, Kruskal-Wallis test); ii) the number of repeats of DDNHNDNHNND in block V (p = 0.1455, Kruskal-Wallis test); or iii) ms4760 profiles (p = 0.1809, Kruskal-Wallis test). CONCLUSIONS: Pfnhe-1 ms4760 was highly diverse in parasite isolates from Dakar (47 different profiles). Three profiles (ms4760-1, ms4760-3 and ms4760-7) were predominant. The number of repeats for block II (DNNND) or block V (DDNHNDNHNND) was not significantly associated with QN susceptibility. New studies, and especially in vivo studies, are necessary to confirm the role of Pfnhe-1 ms4760 as a marker of QN resistance.

Prevalence of molecular markers of Plasmodium falciparum drug resistance in Dakar, Senegal.

BACKGROUND: As a result of the widespread resistance to chloroquine and sulphadoxine-pyrimethamine, artemisinin-based combination therapy (ACT) (including artemether-lumefantrine and artesunate-amodiaquine) has been recommended as a first-line anti-malarial regimen in Senegal since 2006. Intermittent preventive treatments with anti-malarial drugs based on sulphadoxine-pyrimethamine are also given to children or pregnant women once per month during the transmission season. Since 2006, there have been very few reports on the susceptibility of Plasmodium falciparum to anti-malarial drugs. To estimate the prevalence of resistance to several anti-malarial drugs since the introduction of the widespread use of ACT, the presence of molecular markers associated with resistance to chloroquine and sulphadoxine-pyrimethamine was assessed in local isolates at the military hospital of Dakar. METHODS: The prevalence of genetic polymorphisms in genes associated with anti-malarial drug resistance, i.e., Pfcrt, Pfdhfr, Pfdhps and Pfmdr1, and the copy number of Pfmdr1 were evaluated for a panel of 174 isolates collected from patients recruited at the military hospital of Dakar from 14 October 2009 to 19 January 2010. RESULTS: The Pfcrt 76T mutation was identified in 37.2% of the samples. The Pfmdr1 86Y and 184F mutations were found in 16.6% and 67.6% of the tested samples, respectively. Twenty-eight of the 29 isolates with the 86Y mutation were also mutated at codon 184. Only one isolate (0.6%) had two copies of Pfmdr1. The Pfdhfr 108N/T, 51I and 59R mutations were identified in 82.4%, 83.5% and 74.1% of the samples, respectively. The double mutant (108N and 51I) was detected in 83.5% of the isolates, and the triple mutant (108N, 51I and 59R) was detected in 75.3%. The Pfdhps 437G, 436F/A and 613S mutations were found in 40.2%, 35.1% and 1.8% of the samples, respectively. There was no double mutant (437G and 540E) or no quintuple mutant (Pfdhfr 108N, 51I and 59R and Pfdhps 437G and 540E). The prevalence of the quadruple mutant (Pfdhfr 108N, 51I and 59R and Pfdhps 437G) was 36.5%. CONCLUSIONS: Since 2004, the prevalence of chloroquine resistance had decreased. The prevalence of isolates with high-level pyrimethamine resistance is 83.5%. The prevalence of isolates resistant to sulphadoxine is 40.2%. However, no quintuple mutant (Pfdhfr 108N, 51I and 59R and Pfdhps 437G and 540E), which is associated with a high level of sulphadoxine-pyrimethamine resistance, has been identified to date. The resistance to amodiaquine remains moderate.

Ex vivo susceptibility of Plasmodium falciparum isolates from Dakar, Senegal, to seven standard anti-malarial drugs.

BACKGROUND: As a result of widespread chloroquine and sulphadoxine-pyrimethamine resistance, artemisinin-based combination therapy (ACT) (which includes artemether-lumefantrine and artesunate-amodiaquine) has been recommended as a first-line anti-malarial regimen in Senegal since 2006. Since then, there have been very few reports on the ex vivo susceptibility of Plasmodium falciparum to anti-malarial drugs. To examine whether parasite susceptibility has been affected by the widespread use of ACT, the ex vivo susceptibility of local isolates was assessed at the military hospital of Dakar. METHODS: The ex vivo susceptibility of 93 P. falciparum isolates from Dakar was successfully determined using the Plasmodium lactate dehydrogenase (pLDH) ELISA for the following drugs: chloroquine (CQ), quinine (QN), mefloquine (MQ), monodesethylamodiaquine (MDAQ), lumefantrine (LMF), dihydroartemisinin (DHA) and doxycycline (DOX). RESULTS: After transformation of the isolate IC50 in ratio of IC50 according to the susceptibility of the 3D7 reference strain (isolate IC50/3D7 IC50), the prevalence of the in vitro resistant isolates with reduced susceptibility was 50% for MQ, 22% for CQ, 12% for DOX, 6% for both QN and MDAQ and 1% for the drugs LMF and DHA. The highest significant positive correlations were shown between responses to CQ and MDAQ (r = 0.569; P < 0.0001), LMF and QN (r = 0.511; P < 0.0001), LMF and DHA (r = 0.428; P = 0.0001), LMF and MQ (r = 0.413; P = 0.0002), QN and DHA (r = 0.402; P = 0.0003) and QN and MQ (r = 0.421; P = 0.0001). CONCLUSIONS: The introduction of ACT in 2002 has not induced a decrease in P. falciparum susceptibility to the drugs DHA, MDAQ and LMF, which are common ACT components. However, the prevalence of P. falciparum isolates with reduced susceptibility has increased for both MQ and DOX. Taken together, these data suggest that intensive surveillance of the P. falciparum in vitro susceptibility to anti-malarial drugs in Senegal is required.

Development and clinical validation of loop-mediated isothermal amplification (LAMP) assay to diagnose high HBV DNA levels in resource-limited settings.

OBJECTIVE: A massive scale-up of testing and treatment is indicated to globally eliminate hepatitis B virus (HBV) infection. However, access to a polymerase chain reaction (PCR), a key test to quantify HBV DNA levels and determine treatment eligibility, is limited in resource-limited countries. We have developed and evaluated the loop-mediated isothermal amplification (LAMP) assay to diagnose clinically important HBV DNA thresholds defined by the WHO (≥20 000 and ≥ 200 000 IU/mL). METHODS: Pan-genotypic primer sets were designed on conserved HBV gene regions. Accuracy of LAMP to identify highly viraemic patients was evaluated in 400 and 550 HBV-infected people in France and Senegal, respectively. RESULTS: Our primers successfully detected eight major HBV genotypes/sub-genotypes (A1/2/3/B/C/D/E/F) with a detection limit ranging between 40 and 400 IU/mL. In France, the area under the receiver operating characteristic curve (AUROC), sensitivity and specificity of bead-based extraction and real-time turbidimetric LAMP were 0.95 (95% CI 0.93-0.97), 91.1% and 86.0%, respectively, to diagnose HBV DNA ≥20 000 IU/mL; and 0.98 (0.97-0.99), 98.0% and 94.6% for ≥200 000 IU/mL. The performance did not vary by viral genotypes. In Senegal, using a field-adapted method (reagent-free boil-and-spin extraction and inexpensive end-point fluorescence detection), the AUROC, sensitivity and specificity were 0.95 (0.93-0.97), 98.7% and 91.5%, respectively, to diagnose HBV DNA ≥200 000 IU/mL. The assay was not adapted to discriminate low-level viraemia. DISCUSSION: We have developed a simple, rapid (60 min), and inexpensive (US$8/assay) alternative to PCR to diagnose high viraemia ≥200 000 IU/mL. HBV-LAMP may contribute to eliminating HBV mother-to-child transmission by identifying high-risk pregnant women eligible for antiviral prophylaxis in resource-limited countries.

Prevalence and Factors Associated with Maternal Group B Streptococcus Colonization in Madagascar and Senegal.

Maternal group B Streptococcus (GBS) colonization is a major risk factor for neonatal GBS infection. However, data on GBS are scarce in low- and middle-income countries. Using sociodemographic data and vaginal swabs collected from an international cohort of mothers and newborns, this study aimed to estimate the prevalence of GBS colonization among pregnant women in Madagascar (n = 1,603) and Senegal (n = 616). The prevalence was 5.0% (95% CI, 3.9-6.1) and 16.1% (95% CI, 13.1-19.0) in Madagascar and Senegal, respectively. No factors among sociodemographic characteristics, living conditions, and obstetric history were found to be associated independently with GBS colonization in both countries. This community-based study provides one of the first estimates of maternal GBS colonization among pregnant women from Madagascar and Senegal.

Absence of association between polymorphisms in the pfcoronin and pfk13 genes and the presence of Plasmodium falciparum parasites after treatment with artemisinin derivatives in Senegal.

Due to resistance to chloroquine and sulfadoxine/pyrimethamine, treatment for uncomplicated Plasmodium falciparum malaria switched to artemisinin-based combination therapy (ACT) in 2006 in Senegal. Several mutations in the gene encoding the kelch13 helix (pfk13-propeller) have been identified as associated with in vitro and in vivo artemisinin resistance in Southeast Asia. Additionally, three mutations in the pfcoronin gene (G50E, R100K and E107V) have been identified in two culture-adapted Senegalese field isolates that became resistant in vitro to artemisinin after 4 years of intermittent selection with dihydroartemisinin. The aims of this study were to assess the prevalence of pfcoronin and pfk13 mutations in Senegalese field isolates from Dakar and to investigate their association with artemisinin derivative clinical failures. A total of 348 samples of P. falciparum from 327 patients, collected from 2015-2019 in Dakar, were successfully analysed. All sequences had wild-type pfk13 allele. The three mutations (G50E, R100K and E107V), previously identified in parasites with reduced susceptibility to artemisinin, were not found in this study, but a new mutation (P76S) was detected (mean prevalence 16.2%). The P76S mutation was identified in 5 (31.3%) of 16 isolates collected from patients still parasitaemic on Day 3 after ACT treatment and in 31 samples (15.3%) among 203 patients considered successfully cured. There was no significant association between in vivo reduced efficacy to artemisinin derivatives and the P76S mutation (P = 0.151, Fisher's exact test). These data suggest that polymorphisms in pfk13 and pfcoronin are not the best predictive markers for artemisinin resistance in Senegal.

Klebsiella pneumoniae carriage in low-income countries: antimicrobial resistance, genomic diversity and risk factors.

Background Klebsiella pneumoniae (hereafter, Kp) is a major public health threat responsible for high levels of multidrug resistant (MDR) human infections. Besides, Kp also causes severe infections in the community, especially in Asia and Africa. Although most Kp infections are caused by endogenous intestinal carriage, little is known about the prevalence and microbiological characteristics of Kp in asymptomatic human carriage, and attached risk factors including environmental sources exposure. Methods Here, 911 pregnant women from communities in Madagascar, Cambodia, and Senegal were screened for gut colonization by Kp. Characteristics of Kp strains (antimicrobial susceptibility, genomic diversity, virulence, and resistance genes) were defined, and associated risk factors were investigated. Results Kp carriage rate was 55.9%, and Kp populations were highly heterogeneous (6 phylogroups, 325 sequence types, Simpson index 99.6%). One third of Kp isolates had acquired antimicrobial resistance genes. MDR-Kp (11.7% to 39.7%) and extended spectrum beta-lactamase (ESBL)-producing Kp (0.7% to 14.7%) varied among countries. Isolates with virulence genes were detected (14.5%). Environmental exposure factors including food, animal contacts, or hospitalization of household members were associated with carriage of Kp, antimicrobial resistance and hypervirulence. However, risk factors were country-specific and Kp subpopulation-specific. Conclusion This large-scale multicenter study uncovers the huge diversity of Kp in human gut carriage, demonstrates that antimicrobial resistance is widespread in communities of three low-income countries, and underlines the challenges posed by Kp colonization to the control of antimicrobial resistance.

Population structure of human isolates of Streptococcus agalactiae from Dakar and Bangui.

Multilocus sequence types of 163 human Streptococcus agalactiae strains isolated in Bangui and Dakar were analyzed. We identified local specificities in the distribution of sequence types and capsular serotypes. However, the overall population structure is similar to that in the United States and Europe, suggesting that few specific clones colonize humans.

Modulation of in vitro antimalarial responses by polymorphisms in Plasmodium falciparum ABC transporters (pfmdr1 and pfmdr5).

The emergence of resistance to artemisinin-based combination therapies (ACT) was described in Southeast Asia. In this context, the identification of molecular markers of ACT resistance partner drugs is urgently needed for monitoring the emergence and spread of resistance. Polymorphisms in transporter genes, especially of the ATP-binding cassette (ABC) superfamily, have been involved in anti-malarial drug resistance. In this study, the association between the mutations in the P. falciparum multidrug resistance 1 gene (pfmdr1, N86Y, Y184 F, S1034C, N1042D and D1246Y) or repetitive amino acid motifs in pfmdr5 and the ex vivo susceptibility to anti-malarial drugs was evaluated. Susceptibility to chloroquine, quinine, monodesethylamodiaquine, lumefantrine, piperaquine, pyronaridine, mefloquine and dihydroartemisinin was assessed in 67 Senegalese isolates. The shorter DNNN motif ranged from to 2 to 11 copy repeats, and the longer DHHNDHNNDNNN motif ranged from 0 to 2 in pfmdr5. The present study showed the association between repetitive amino acid motifs (DNNN-DHHNDDHNNDNNN) in pfmdr5 and in vitro susceptibility to 4-aminoquinoline-based antimalarial drugs. The parasites with 8 and more copy repeats of DNNN in pfmdr5 were significantly more susceptible to piperaquine. There was a significant association between parasites whose DHHNDHNNDNNN motif was absent and replaced by DHHNDNNN, DHHNDHNNDHNNDNNN or DHHNDHNNDHNNDHNNDNNN and increased susceptibility to chloroquine, monodesethylamodiaquine and pyronaridine. A significant association between both the wild-type allele N86 in pfmdr1 and the N86-184 F haplotype and reduced susceptibility to lumefantrine was confirmed. Further studies with a large number of samples are required to validate the association between these pfmdr5 alleles and the modulation of 4-aminoquinoline-based antimalarial drug susceptibility.