Association between telomere length and Plasmodium falciparum malaria endemicity in sub-Saharan Africans

Leukocyte telomere length (LTL) varies significantly across human populations, with individuals of African ancestry having longer LTL than non-Africans. However, the genetic and environmental drivers of LTL variation in Africans remain largely unknown. We report here on the relationship between LTL, genetics, and a variety of environmental and climatic factors in ethnically diverse African adults (n = 1,818) originating from Botswana, Tanzania, Ethiopia, and Cameroon. We observe significant variation in LTL among populations, finding that the San hunter-gatherers from Botswana have the longest leukocyte telomeres and that the Fulani pastoralists from Cameroon have the shortest telomeres. Genetic factors explain ∼50% of LTL variation among individuals. Moreover, we observe a significant negative association between Plasmodium falciparum malaria endemicity and LTL while adjusting for age, sex, and genetics. Within Africa, adults from populations indigenous to areas with high malaria exposure have shorter LTL than those in populations indigenous to areas with low malaria exposure. Finally, we explore to what degree the genetic architecture underlying LTL in Africa covaries with malaria exposure.

Integrative functional genomic analyses identify genetic variants influencing skin pigmentation in Africans

Skin color is highly variable in Africans, yet little is known about the underlying molecular mechanism. Here we applied massively parallel reporter assays to screen 1,157 candidate variants influencing skin pigmentation in Africans and identified 165 single-nucleotide polymorphisms showing differential regulatory activities between alleles. We combine Hi-C, genome editing and melanin assays to identify regulatory elements for MFSD12, HMG20B, OCA2, MITF, LEF1, TRPS1, BLOC1S6 and CYB561A3 that impact melanin levels in vitro and modulate human skin color. We found that independent mutations in an OCA2 enhancer contribute to the evolution of human skin color diversity and detect signals of local adaptation at enhancers of MITF, LEF1 and TRPS1, which may contribute to the light skin color of Khoesan-speaking populations from Southern Africa. Additionally, we identified CYB561A3 as a novel pigmentation regulator that impacts genes involved in oxidative phosphorylation and melanogenesis. These results provide insights into the mechanisms underlying human skin color diversity and adaptive evolution.

Diverse African genomes reveal selection on ancient modern human introgressions in Neanderthals

Comparisons of Neanderthal genomes to anatomically modern human (AMH) genomes show a history of Neanderthal-to-AMH introgression stemming from interbreeding after the migration of AMHs from Africa to Eurasia. All non-sub-Saharan African AMHs have genomic regions genetically similar to Neanderthals that descend from this introgression. Regions of the genome with Neanderthal similarities have also been identified in sub-Saharan African populations, but their origins have been unclear. To better understand how these regions are distributed across sub-Saharan Africa, the source of their origin, and what their distribution within the genome tells us about early AMH and Neanderthal evolution, we analyzed a dataset of high-coverage, whole-genome sequences from 180 individuals from 12 diverse sub-Saharan African populations. In sub-Saharan African populations with non-sub-Saharan African ancestry, as much as 1% of their genomes can be attributed to Neanderthal sequence introduced by recent migration, and subsequent admixture, of AMH populations originating from the Levant and North Africa. However, most Neanderthal homologous regions in sub-Saharan African populations originate from migration of AMH populations from Africa to Eurasia ∼250 kya, and subsequent admixture with Neanderthals, resulting in ∼6% AMH ancestry in Neanderthals. These results indicate that there have been multiple migration events of AMHs out of Africa and that Neanderthal and AMH gene flow has been bi-directional. Observing that genomic regions where AMHs show a depletion of Neanderthal introgression are also regions where Neanderthal genomes show a depletion of AMH introgression points to deleterious interactions between introgressed variants and background genomes in both groups-a hallmark of incipient speciation.

Genomic characterization of HLA class I and class II genes in ethnically diverse sub-Saharan African populations: A report on novel HLA alleles

HLA allelic variation has been well studied and documented in many parts of the world. However, African populations have been relatively under-represented in studies of HLA variation. We have characterized HLA variation from 489 individuals belonging to 13 ethnically diverse populations from rural communities from the African countries of Botswana, Cameroon, Ethiopia, and Tanzania, known to practice traditional subsistence lifestyles using next generation sequencing (Illumina) and long-reads from Oxford Nanopore Technologies. We identified 342 distinct alleles among the 11 HLA targeted genes: HLA-A, -B, -C, -DRB1, -DRB3, -DRB4, -DRB5, -DQA1, -DQB1, -DPA1, and -DPB1, with 140 of those alleles containing novel sequences that were submitted to the IPD-IMGT/HLA database. Sixteen of the 140 alleles contained novel content within the exonic regions of the genes, while 110 alleles contained novel intronic variants. Four alleles were found to be recombinants of already described HLA alleles and 10 alleles extended the sequence content of already described alleles. All 140 alleles include complete allelic sequence from the 5' UTR to the 3' UTR that are inclusive of all exons and introns. This report characterizes the HLA allelic variation from these individuals and describes the novel allelic variation present within these specific African populations.

Pre-Treatment HIV Drug Resistance and Genetic Diversity in Cameroon: Implications for First-Line Regimens

The efficacy of first-line antiretroviral therapy (ART) may be hampered by the presence of HIV drug resistance (HIVDR). We described HIV-1 pre-treatment drug resistance (PDR) patterns, effect of viral clades on PDR, and programmatic implications on first-line regimens in Cameroon. A sentinel surveillance of PDR was conducted from 2014 to 2019. Sequencing of HIV-1 protease and reverse transcriptase was performed, and HIVDR was interpreted using Stanford HIVdb.v.9.4. In total, 379 sequences were obtained from participants (62% female, mean age 36 ± 10 years). The overall PDR rate was 15.0% [95% CI: 11.8-19.0] nationwide, with significant disparity between regions (p = 0.03). NNRTI PDR was highest (12.4%), of which 7.9% had DRMs to EFV/NVP. Two regions had EFV/NVP PDR above the 10% critical threshold, namely the Far North (15%) and East (10.9%). Eighteen viral strains were identified, predominated by CRF02_AG (65.4%), with no influence of genetic diversity PDR occurrence. TDF-3TC-DTG predictive efficacy was superior (98.4%) to TDF-3TC-EFV (92%), p < 0.0001. The overall high rate of PDR in Cameroon, not substantially affected by the wide HIV-1 genetic diversity, underscores the poor efficacy of EFV/NVP-based first-line ART nationwide, with major implications in two regions of the country. This supports the need for a rapid transition to NNRTI-sparing regimens, with TDF-3TC-DTG having optimal efficacy at the programmatic level.

Impact of natural selection on global patterns of genetic variation and association with clinical phenotypes at genes involved in SARS-CoV-2 infection

Human genomic diversity has been shaped by both ancient and ongoing challenges from viruses. The current coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has had a devastating impact on population health. However, genetic diversity and evolutionary forces impacting host genes related to SARS-CoV-2 infection are not well understood. We investigated global patterns of genetic variation and signatures of natural selection at host genes relevant to SARS-CoV-2 infection (angiotensin converting enzyme 2 [ACE2], transmembrane protease serine 2 [TMPRSS2], dipeptidyl peptidase 4 [DPP4], and lymphocyte antigen 6 complex locus E [LY6E]). We analyzed data from 2,012 ethnically diverse Africans and 15,977 individuals of European and African ancestry with electronic health records and integrated with global data from the 1000 Genomes Project. At ACE2, we identified 41 nonsynonymous variants that were rare in most populations, several of which impact protein function. However, three nonsynonymous variants (rs138390800, rs147311723, and rs145437639) were common among central African hunter-gatherers from Cameroon (minor allele frequency 0.083 to 0.164) and are on haplotypes that exhibit signatures of positive selection. We identify signatures of selection impacting variation at regulatory regions influencing ACE2 expression in multiple African populations. At TMPRSS2, we identified 13 amino acid changes that are adaptive and specific to the human lineage compared with the chimpanzee genome. Genetic variants that are targets of natural selection are associated with clinical phenotypes common in patients with COVID-19. Our study provides insights into global variation at host genes related to SARS-CoV-2 infection, which have been shaped by natural selection in some populations, possibly due to prior viral infections.

Impact of natural selection on global patterns of genetic variation, and association with clinical phenotypes, at genes involved in SARS-CoV-2 infection

We investigated global patterns of genetic variation and signatures of natural selection at host genes relevant to SARS-CoV-2 infection (ACE2, TMPRSS2, DPP4, and LY6E). We analyzed novel data from 2,012 ethnically diverse Africans and 15,997 individuals of European and African ancestry with electronic health records, and integrated with global data from the 1000GP. At ACE2, we identified 41 non-synonymous variants that were rare in most populations, several of which impact protein function. However, three non-synonymous variants were common among Central African hunter-gatherers from Cameroon and are on haplotypes that exhibit signatures of positive selection. We identify strong signatures of selection impacting variation at regulatory regions influencing ACE2 expression in multiple African populations. At TMPRSS2, we identified 13 amino acid changes that are adaptive and specific to the human lineage. Genetic variants that are targets of natural selection are associated with clinical phenotypes common in patients with COVID-19.

Impact of natural selection on global patterns of genetic variation, and association with clinical phenotypes, at genes involved in SARS-CoV-2 infection

We investigated global patterns of genetic variation and signatures of natural selection at host genes relevant to SARS-CoV-2 infection ( ACE2, TMPRSS2, DPP4 , and LY6E ). We analyzed novel data from 2,012 ethnically diverse Africans and 15,997 individuals of European and African ancestry with electronic health records, and integrated with global data from the 1000GP. At ACE2 , we identified 41 non-synonymous variants that were rare in most populations, several of which impact protein function. However, three non-synonymous variants were common among Central African hunter-gatherers from Cameroon and are on haplotypes that exhibit signatures of positive selection. We identify strong signatures of selection impacting variation at regulatory regions influencing ACE2 expression in multiple African populations. At TMPRSS2 , we identified 13 amino acid changes that are adaptive and specific to the human lineage. Genetic variants that are targets of natural selection are associated with clinical phenotypes common in patients with COVID-19.

Preinvasive cervical lesions and high prevalence of human papilloma virus among pregnant women in Cameroon

Introduction

With the exception of breast cancer, gynecologic neoplasms constitute the most common cancers that complicate pregnancy. Pregnancy therefore presents a window of opportunity for all pregnant women who do not take part in routine free cervical cancer screening program to undergo a free voluntary cytological test and human papillomavirus (HPV) DNA testing. This study aimed to determine prevalent HPV genotypes among pregnant women using exfoliated cells from cervical swabs and determine risk factors responsible for the upsurge of cervical precancerous lesions.

Methods

In a cross-sectional study conducted from October 2017 to March 2018, a total of 482 pregnant women were enrolled. Cervical swabs and samples for cytology were collected from each enrolled participant during their routine prenatal consultation. The Papanicolaou's (Pap) staining technique was performed and all cervical swab samples were amplified through conventional PCR. HPV genotypes were identified using the Roche Linear Array Genotyping Assay. SAS 9.2 software (SAS Institute Inc., USA) was used for statistical analysis and p values >0.05 were considered significant.

Results

Among the 482 participants, 354 (73.4%) had normal cytology and 128 (26.6%) had abnormal cytology. HPV DNA was identified in 62/464 (13.4%). The most prominent HPV types identified were HPV 16 (24%), HPV 18 (36.4%), HPV 45 (28%), HPV 53 (18.9%) and HPV 67 (24.3%). Early intercourse, number of sexual partners and age at first pregnancy were some of the risk factors that influenced the etiology of preinvasive cervical lesion.

Conclusions

Prevalent HPV types identified in our study were HPV 16, 18, 45, 53 and 67. Organizing effective screening programs in prenatal care facilities is crucial in order to detect prevalent HR-HPV types and precursors for cervical lesions. The addition of HPV vaccination in the national immunization program with focus on the different epidemiological HPV genotypes circulating in the country is warranted.

Lifestyle and the presence of helminths is associated with gut microbiome composition in Cameroonians

BACKGROUND

African populations provide a unique opportunity to interrogate host-microbe co-evolution and its impact on adaptive phenotypes due to their genomic, phenotypic, and cultural diversity. We integrate gut microbiome 16S rRNA amplicon and shotgun metagenomic sequence data with quantification of pathogen burden and measures of immune parameters for 575 ethnically diverse Africans from Cameroon. Subjects followed pastoralist, agropastoralist, and hunter-gatherer lifestyles and were compared to an urban US population from Philadelphia.

RESULTS

We observe significant differences in gut microbiome composition across populations that correlate with subsistence strategy and country. After these, the variable most strongly associated with gut microbiome structure in Cameroonians is the presence of gut parasites. Hunter-gatherers have high frequencies of parasites relative to agropastoralists and pastoralists. Ascaris lumbricoides, Necator americanus, Trichuris trichiura, and Strongyloides stercoralis soil-transmitted helminths ("ANTS" parasites) significantly co-occur, and increased frequency of gut parasites correlates with increased gut microbial diversity. Gut microbiome composition predicts ANTS positivity with 80% accuracy. Colonization with ANTS, in turn, is associated with elevated levels of TH1, TH2, and proinflammatory cytokines, indicating an association with multiple immune mechanisms. The unprecedented size of this dataset allowed interrogation of additional questions-for example, we find that Fulani pastoralists, who consume high levels of milk, possess an enrichment of gut bacteria that catabolize galactose, an end product of lactose metabolism, and of bacteria that metabolize lipids.

CONCLUSIONS

These data document associations of bacterial microbiota and eukaryotic parasites with each other and with host immune responses; each of these is further correlated with subsistence practices.

Programme quality indicators of HIV drug resistance among adolescents in urban versus rural settings of the centre region of Cameroon

BACKGROUND

The high rate of mortality among HIV-vertically infected adolescents might be favoured by HIV drug resistance (HIVDR) emergence, which calls for timeous actions in this underserved population. We thus sought to evaluate program quality indicators (PQIs) of HIVDR among HIV-vertically infected adolescents on antiretroviral therapy (ART).

METHODS

A study was conducted in the Centre region of Cameroon among adolescents (10-19 years) receiving ART in two urban (The Mother-Child Centre of the Chantal BIYA Foundation, the National Social Welfare Hospital) and three rural (Mfou District Hospital, Mbalmayo District Hospital and Nkomo Medical Center) health facilities. Following an exhaustive sampling from ART registers, patient medical files and pharmacy records, data was abstracted for seven PQIs: on-time drug pick-up; retention in care; pharmacy stock outs; dispensing practices; viral load coverage; viral suppression and adequate switch to second-line. Performance in PQIs was interpreted following the WHO-recommended thresholds (desirable, fair and/or poor); with p < 0.05 considered significant.

RESULTS

Among 967 adolescents (888 urban versus 79 rural) registered in the study sites, validated data was available for 633 (554 in urban and 79 in rural). Performance in the urban vs. rural settings was respectively: on-time drug pick-up was significantly poorer in rural (79% vs. 46%, p = 0.00000006); retention in care was fair in urban (80% vs. 72%, p = 0.17); pharmacy stock outs was significantly higher in urban settings (92% vs. 50%, p = 0.004); dispensing practices was desirable (100% vs. 100%, p = 1.000); viral load coverage was desirable only in urban sites (84% vs. 37%, p < 0.0001); viral suppression was poor (33% vs. 53%, p = 0.08); adequate switch to second-line varied (38.1% vs. 100%, p = 0.384).

CONCLUSION

Among adolescents on ART in Cameroon, dispensing practices are appropriate, while adherence to ART program and viral load coverage are better in urban settings. However, in both urban and rural settings, pharmacy stock outs, poor viral suppression and inadequate switch to second-line among adolescents require corrective public-health actions to limit HIVDR and to improve transition towards adult care in countries sharing similar programmatic features.

Near full genome characterization of HIV-1 unique recombinant forms in Cameroon reveals dominant CRF02_AG and F2 recombination patterns

INTRODUCTION

In Cameroon, a manifold diversity of HIV strains exists with CRF02_AG and unique recombinant forms (URFs) being the predominant strains. In recent years, a steady increase in URFs and clade F2 viruses has been monitored through partial genome sequencing. There is an information gap in the characterization of emerging URFs along the full genome, which is needed to address the challenges URFs pose towards diagnosis, treatment and HIV-1 vaccine design.

METHOD

Eighteen Cameroonian URFs from samples collected between the years 2000 and 2015 were studied using a newly developed near full genome sequencing (NFGS) protocol based on variable nested RT-PCRs with a versatile primer set. Near full genomes were characterized for recombination patterns and sequence signatures with possible impact on antiretroviral treatment or Env-directed immune responses. Third-generation sequencing (3GS) of near full or half genomes (HGs) gave insight into intra-patient URF diversity.

RESULTS

The characterized URFs were composed of a broad variety of subtypes and recombinants including A, F, G, CRF01_AE, CRF02_AG and CRF22_01A1. Phylogenetic analysis unveiled dominant CRF02_AG and F2 recombination patterns. 3GS indicated a high intra-patient URF diversity with up to four distinct viral sub-populations present in plasma at the same time. URF pol genomic analysis revealed a number of accessory drug resistance mutations (DRMs) in the ART-naïve participants. Genotypic env analysis suggests CCR5 usage in 14/18 samples and identified deviations at residues, critical for gp120/gp41 interphase and CD4 binding site broadly neutralizing antibodies in more than half of the studied URFs. V1V2 sites of immune pressure in the human RV144 vaccine study varied in more than a third of URFs.

CONCLUSIONS

This study identified novel mosaic patterns in URFs in Cameroon. In line with the regional predominance of CRF_02AG and the increased prevalence of clade F2, prominent CRF_02AG and F2 background patterns were observed underlying the URFs. In the context of the novel mosaic genomes, the impact of the identified accessory DRMs and Env epitope variations on treatment and immune control remains elusive. The evolving diversity of HIV-1 URFs in Cameroon requires continuous monitoring to respond to the increasing challenges for diagnosis, antiretroviral treatment and prevention.

OC 8378 REQUIREMENTS FOR THE ETHICAL CONDUCT OF CLINICAL RESEARCH IN CAMEROON, SUB-SAHARAN AFRICA: THE IMPORTANCE OF ACTIVE MONITORING

Background

Previous evaluation of the state of ethics regulation in Cameroon revealed: law regulating clinical research is lacking; existing committees lack infrastructure and financial support to sustainably review and effectively monitor approved protocols. The present Cameroon National Ethics Committee (CNEC)-EDCTP project aimed at implementing and evaluating active monitoring of clinical research in Cameroon.

Methods

Between 2011–2013, approved clinical trials and protocols involving transfer of biological materials abroad were consecutively monitored. The monitoring tool, a questionnaire on the conformity of key documents e.g. research protocols, ethical clearance, informed consent documents, investigator’s brochure, with a focus on GCP standards was sent to promoters/investigators ten days prior to the field visit. Teams of two-three monitors, made up of CNEC members and independent consultants, were mobilised per site (hospital/research institute/NGO). Reports with key recommendations were submitted to CNEC for review and approval, to different promoters/investigators, and the Regulatory Authority for action; the monitoring summary was submitted to EDCTP.

Results

Up to 22 site visits were done throughout the country, monitoring about 30 protocols within 11 hospitals, 9 research institutes, a National Programme and a non-governmental organisation. All sites had ethical clearance and administrative authorisation for research. From the registered number of research participants, less than half of the signed consent forms were available. Other issues were the lack of full involvement of local investigators, inexistence of material transfer and data sharing agreements with collaborative studies, non-implication of study communities/participants. As educators-consultants, monitors formulated recommendations to investigators, ethics committees and regulatory authority, insisting on the implication of local PI/collaborators with defined percentages of time to be devoted for research and good participatory practice among research communities/participants.

Conclusion

Active monitoring shows some formality in the application of ethical/administrative clearance in Cameroon. However, complex issues raised confirm the necessity of continuous monitoring to meet the high standards for clinical research ethics in Cameroon.

PO 8190 RISK FACTORS OF SEVERE HEPATOTOXICITY AMONG HIV-1 PATIENTS INITIATED ON HIGHLY ACTIVE ANTIRETROVIRAL THERAPY IN THE NORTHWEST REGION OF CAMEROON

Background

Hepatotoxicity due to highly active antiretroviral therapy (HAART) has gained prominent attention since it can be affected by many factors. The aim of this study was to determine the prevalence of hepatotoxicity and related risk factors of severe hepatotoxicity following HAART initiation.

Methods

A total of 100 newly diagnosed HIV drug-naive patients within the age range of 18–61 years were recruited and followed up for 24 weeks and were placed on either Tenofovir (TDF)+Lamivudine (3TC)+Efavirenz (EFV) or Zidovudine (AZT) +Lamivudine + Nevirapine (NVP) or Zidovudine +Lamivudine + Efavirenz regimen. Sociodemographic data was obtained using pretested questionnaires. Venous blood samples were collected to measure aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), using colometric enzymatic reaction. Hepatotoxicity was classified based on age and sex. Data was analysed using SPSS.

Results

The level of significance was set at 5%. A total of 37 (38%) and 49 (49%) patients presented with hepatotoxicity; 15% and 28% of these patients had severe hepatotoxicity at 4 and 24 weeks, respectively. Serum levels of all enzymes increased significantly (p<0.05) with increased treatment duration. Univariate analysis revealed that the risk factor of developing severe hepatotoxicity was significantly (p<0.05) greater in patients<30 years, males, low BMI, low monthly income earners and patient on AZT+3TC +NVP regimen. While multivariate analysis at p<0.09 showed that age <30 years, Low BMI, low monthly income, or the use of AZT+3TC +NVP regimen were independent risk factors.

Conclusion

Low BMI,<30 years, low monthly income and the use of AZT+3TC+NVP regimen were identifiable risk factors for the development of severe hepatotoxicity. As such, these factors should be considered as important for strategy by clinicians to prevent hepatotoxicity.

Development of a Versatile, Near Full Genome Amplification and Sequencing Approach for a Broad Variety of HIV-1 Group M Variants

Near full genome sequencing (NFGS) of HIV-1 is required to assess the genetic composition of HIV-1 strains comprehensively. Population-wide, it enables a determination of the heterogeneity of HIV-1 and the emergence of novel/recombinant strains, while for each individual it constitutes a diagnostic instrument to assist targeted therapeutic measures against viral components. There is still a lack of robust and adaptable techniques for efficient NFGS from miscellaneous HIV-1 subtypes. Using rational primer design, a broad primer set was developed for the amplification and sequencing of diverse HIV-1 group M variants from plasma. Using pure subtypes as well as diverse, unique recombinant forms (URF), variable amplicon approaches were developed for NFGS comprising all functional genes. Twenty-three different genomes composed of subtypes A (A1), B, F (F2), G, CRF01_AE, CRF02_AG, and CRF22_01A1 were successfully determined. The NFGS approach was robust irrespective of viral loads (≥306 copies/mL) and amplification method. Third-generation sequencing (TGS), single genome amplification (SGA), cloning, and bulk sequencing yielded similar outcomes concerning subtype composition and recombinant breakpoint patterns. The introduction of a simple and versatile near full genome amplification, sequencing, and cloning method enables broad application in phylogenetic studies of diverse HIV-1 subtypes and can contribute to personalized HIV therapy and diagnosis.

Identification and quantification of 19 pharmaceutical active compounds and metabolites in hospital wastewater in Cameroon using LC/QQQ and LC/Q-TOF

Human pharmaceutical residues are a serious environmental concern. They have been reported to have eco, geno, and human toxic effects, and thus their importance as micropollutants cannot be ignored. These have been studied extensively in Europe and North America. However, African countries are still lagging behind in research on these micropollutants. In this study, the wastewaters of the University Teaching Hospital of Yaoundé (UTHY) were screened for the presence of active pharmaceutical ingredients and their metabolites. The screening was carried out using two methods: high-performance liquid chromatography coupled to a triple quadrupole analyzer (LC/QQQ) and high-performance coupled to a mass spectrometer with a time of flight analyzer (LC/Q-TOF). A total of 19 active pharmaceutical ingredients and metabolites were identified and quantified. The compounds identified include paracetamol (211.93 μg/L), ibuprofen (141 μg/L), tramadol (76 μg/L), O-demethyltramadol (141 μg/L), erythromycinanhydrate (7 μg/L), ciprofloxacin (24 μg/L), clarinthromycine (0.088 μg/L), azitromycine (0.39 μg/L), sulfamethoxazole 0.16 μg/L), trimetoprime (0.27 μg/L), caffeine (5.8 μg/L), carnamaeepine (0.94 μg/L), atenolol (0.43 μg/L), propranolol (0.3 μg/L), cimetidine (34 μg/L), hydroxy omeprazole (5 μg/L), diphenhydramine (0.38 μg/L), metformine (154 μg/L), and sucralose (13.07 μg/L).

Investigating zoonotic infection barriers to ape Plasmodium parasites using faecal DNA analysis

African apes are endemically infected with numerous Plasmodium spp. including close relatives of human Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale, and Plasmodium malariae. Although these ape parasites are not believed to pose a zoonotic threat, their ability to colonise humans has not been fully explored. In particular, it remains unknown whether ape parasites are able to initiate exo-erythrocytic replication in human hepatocytes following the bite of an infective mosquito. Since animal studies have shown that liver stage infection can result in the excretion of parasite nucleic acids into the bile, we screened faecal samples from 504 rural Cameroonians for Plasmodium DNA. Using pan-Laverania as well as P. malariae- and P. vivax-specific primer sets, we amplified human P. falciparum (n = 14), P. malariae (n = 1), and P. ovale wallikeri (n = 1) mitochondrial sequences from faecal DNA of 15 individuals. However, despite using an intensified PCR screening approach we failed to detect ape Laverania, ape P. vivax or ape P. malariae parasites in these same subjects. One faecal sample from a hunter-gatherer contained a sequence closely related to the porcupine parasite Plasmodium atheruri. Since this same faecal sample also contained porcupine mitochondrial DNA, but a matching blood sample was Plasmodium-negative, it is likely that this hunter-gatherer consumed Plasmodium-infected bushmeat. Faecal Plasmodium detection was not secondary to intestinal bleeding and/or infection with gastrointestinal parasites, but indicative of blood parasitaemia. Quantitative PCR identified 26-fold more parasite DNA in the blood of faecal Plasmodium-positive than faecal Plasmodium-negative individuals (P = 0.01). However, among blood-positive individuals only 10% - 20% had detectable Plasmodium sequences in their stool. Thus, faecal screening of rural Cameroonians failed to uncover abortive ape Plasmodium infections, but detected infection with human parasites, albeit with reduced sensitivity compared with blood analysis.

Pre-vaccine circulating group a rotavirus strains in under 5 years children with acute diarrhea during 1999-2013 in Cameroon

The aim of this review was to assess all the studies on rotavirus G and P characterization during the pre-vaccine period (1999-2013) in Cameroon to have a better basis for post-vaccine introduction evaluations. A retrospective study was done through a comprehensive review of published (PubMed, Google Scholar) and accessible unpublished data on rotavirus G and P genotypes circulating in five regions of Cameroon. Descriptive data were expressed as frequencies tables and proportions. A total of 1844 rotavirus positive cases were analyzed. In all, 1534 strains were characterized for the P (VP4) specificity. Six different VP4 genotypes were observed, including P [4], P [6], P [8], P [9], P [10] and P [14]. The most predominant P genotypes were P [8] at 42.6%, and P [6] at 37.9%. Mixed infections were observed at 5.3%, whereas 4.1% of the strains were P non-typeable. A total of 1518 rotavirus strains were characterized for the G (VP7) specificity. VP7 genotypes G1, G2, G3, G4, G5, G6, G8, G9, G10 and G12 were observed. G1 (35.3%), G3 (19.5%), G2 (14.9%) and G12 (10.1%) were the predominant G genotypes while G5 and G10 were least prevalent at 0.06% each. Approximately 5.1% of all strains were G non-typeable whereas 5.3% were mixed G genotypes. A total of 1472 strains were characterized for both G and P genes, from which 38 different G-P combinations were observed. Overall, G1P [8] (22%) was identified as the predominant rotavirus strain circulating in Cameroon followed by G3P [6] (15%). In conclusion, we observed that the genotypes identified in Cameroon during 1999-2013 were partially covered by the two WHO recommended rotavirus vaccines. This review provides comprehensive up-to-date information on rotavirus strain surveillance in Cameroon during the pre-vaccination era.

Antibacterial activities and toxicological study of the aqueous extract from leaves of Alchornea cordifolia (Euphorbiaceae)

BACKGROUND

A. cordifolia is a plant widely used in Africa to solve many health problems. In Cameroon, it is used in the treatment of urogenital infections. As a continuation of our search for pharmacologically active agents from natural sources, the antimicrobial activity of A. cordifolia leaf extracts against E. coli and the toxicity of this extract were investigated.

METHODS

The antibacterial activity of the aqueous extract from leaves of Alchornea cordifolia was carried out in vitro on Escherichia coli, as well as in vivo on E. coli-infected rat model. Phytochemical screening was performed using standard methods. The acute toxicity was investigated in mice, while at the end of treatment of infected rats, some biochemical, hematological and histological markers of toxicity were evaluated.

RESULTS

The extract exhibited a bacteriostatic activity with MIC value of 1500 μg/ml. Phytochemical screening revealed the presence of phenols, tannins, triterpens, flavonoids, alkaloids, anthraquinones, anthocyanins, saponins and coumarins in the extract. The acute toxicity study showed LD50 values of 8.6 g/kg and 3.8 g/kg in male and female mice respectively. In vivo, the oral administration of the extract showed a dose-dependent decrease of the bacterial load as the extract at 232, 112 and 58 g/kg were able to eradicate the infection after 9, 11 and 13 days of treatment. The infected rats showed a significant (p < 0.05) increase in the level of serum creatinine, ALAT, white blood cells, and a significant (p < 0.05) decrease in the level of food and water intake, the relative weight of lungs, heart and spleen. In the treated rats, a significant (p < 0.05) increase in food and water intake and ALAT was observed at the doses of 116 and 232 mg/kg. A decrease in the red blood cells count and serum protein levels was also observed. These observations corroborate liver damages as revealed by the histopathological examination of the cross sections of this organ.

CONCLUSION

The results of this assay thus showed that the extract of A. cordifolia is bacteriostatic, therapeutic at 58 g/kg bw and may be considered as slightly and almost non-toxic on females and males mice respectively.

Intestinal carriage of Extended Spectrum Beta-Lactamase producing E. coli in women with urinary tract infections, Cameroon

INTRODUCTION

During the last decade, the prevalence of the intestinal carriage of extended spectrum beta-lactamases - producing Escherichia coli (ESBL-E. coli) has continued to increase worldwide in the community, especially in developing countries. Hence, we undertook a study to determine the ESBL-E. coli fecal carriage rate and the associated risk factors in Cameroonian women.

METHODOLOGY

A total of 86 women suspected of community-acquired urinary tract infections (UTI) were included in 10 health structures from May 2011 to April 2012. After filling a questionnaire, they provided a stool sample that was plated on selective media for ESBL producing bacteria. The identification of strains was obtained with mass spectrometry and the antibiotic susceptibility by disk diffusion in agar media. The ESBL type was determined by PCR. The relative abundance of ESBL-E. coli was measured for positive samples. Eventually, the presence of antibiotics in stool was assessed.

RESULTS

The carriage rate of ESBL-E. coli was 57/86 (66.3%). Phenotypic and molecular characterization showed that all ESBL-E. coli strains contained group 1 CTX-M enzymes. Multivariate analysis showed that ESBL-E. coli fecal carriage was associated with the presence of antibiotics in stools (p < 0.05). Although not significant, mean ESBL relative abundance tended to be higher in patients with antibiotic exposure.

CONCLUSIONS

Our results show that the carriage of ESBL-E. coli fecal carriage in women with UTI suspicion from the Cameroonian community is extremely high and associated with recent antibiotic intake.

Antityphoid properties and toxicity evaluation of Harungana madagascariensis Lam (Hypericaceae) aqueous leaf extract

CONTEXT

Harungana madagascariensis Lam is commonly used in Cameroonian folk medicine for the treatment of malaria and typhoid fever.

OBJECTIVE

To investigate the therapeutic potentials of H. madagascariensis aqueous leaf extract for the treatment of salmonellosis (e.g. typhoid fever, gastroenteritis).

MATERIALS AND METHODS

A Salmonella Typhimurium-infected rat model was used. The faeces of these rats were analysed for viable Salmonella Typhimurium before and after infection, and during the treatment period. The physiological, biochemical and histopathological markers of possible side effects of the extract were also studied using standard methods and kits.

RESULTS AND DISCUSSION

The in vivo antisalmonellal study revealed that this extract significantly (P<0.05) reduced the number of viable Salmonella Typhimurium recovered from faeces, and could stop salmonellosis after 10 days of treatment for male and female rats, with non-toxic doses. However, the biochemical and histological analyses revealed that at relatively high-doses (≥100mg/kg for females and 200mg/kg for males) the extract could induce liver damage, as illustrated by a rise of serum transaminases (ALT and AST), significant inflammation of the parenchyma and portal vein, as well as cell necrosis. There were also increases in cholesterol levels in both sexes. No significant unwanted side effect of the extract was observed on the kidney, as shown by both serum and urinary creatinine, and urinary protein levels.

CONCLUSION

The results obtained showed that H. madagascariensis has a promising antisalmonellal effect and, therefore, the potential to provide an effective treatment against salmonellosis, including typhoid fever.

Relationship between multiple drug resistance and biofilm formation in Staphylococcus aureus isolated from medical and non-medical personnel in Yaounde, Cameroon

Introduction

Monitoring the prevalence of nasal carriage of multiple drug resistance (MDR) Staphylococcus aureus (SA) strains in hospital personnel is essential. These strains when transmitted from hospital personnel to patients with already weakened immune states or in-built medical devices, may limit the latter's treatment options. This study aimed at assessing the potential exposure of patients to these MDR SA in a resource-limited hospital setting by assessing the prevalence and relationship between antimicrobial susceptibility and biofilm forming capacity of SA isolates from hospital personnel.

Methods

A total of 59 bacteria isolates phenotypically identified as Staphylococcus aureus obtained from medical (39) and non-medical personnel (20) in Yaounde were used in the study. Multiple drug resistance defined as resistance to four or more of twelve locally used antibiotics were determined by Kirby Bauer disc diffusion technique whereas quantification of biofilm production was by the microtitre plate method.

Results

Among the 59 SA isolates, the prevalence of MDR was 50.9%. Among medical personnel 48.7% had MDR as against 55.9% for non-medical personnel (p-value=0.648). The overall percentage of weak biofilm producers was 35.6%. Although the prevalence of weak biofilm formers was higher in isolates from non-medical personnel (40%) than medical personnel (33.3%) the difference was not statistically significant (p-value= 0.246). Slightly less than half (42.9%) of the weak biofilm producers were MDR.

Conclusion

Considering the high rates of MDR and that slightly less than half of biofilm formers were MDR, these trends need to be monitored regularly among hospital personnel in Yaounde.