Resistance pattern of enterobacteriaceae isolates from urinary tract infections to selected quinolones in Yaoundé

Introduction: It is estimated that 150 million urinary tract infections (UTIs) occur yearly worldwide, resulting in more than 6 billion dollar in direct healthcare cost. The etiology of UTIs is predictable, with Escherichia coli, an Enterobacteriaceae being the principal pathogen. Quinolones are usually the drug of choice. In this study, we report the resistance pattern of Enterobacteriaceae isolates from UTIs to quinolones among in-patients and out-patients at the Yaoundé Reference Hospital in Cameroon. Methods: A cross-sectional descriptive study was carried out for a ten-month period. Consecutive clean-catch mid-stream urine samples were collected from 207 in and out-patients. Identification was done using the Api 20E, and susceptibility testing using the Kirby Bauer’s disc diffusion method and the MIC was done using the E-test. Results: Out of the 207 isolates, 58(28.0%) were found to be resistant to all the quinolones used in the study. The resistances observed by species were in the order: Enterobacter 4(30.8%); Klebsiella 19(29.7%); Escherichia25 (29.4%); Proteus 2(11.8%); Serratia 4(25.0%). Quinolone resistance for Escherichia was 42.9% for In-Patients (IP) and 16.3% for Out-Patient (OP) (P-value = 0.006); Klebsiella 35.9% for IP and 20% for OP; Proteus 11.1% for IP and 12.5% for OP; Serratia 18.2% for IP and 40% for OP;Enterobacter 22.2 for IP and 50% for OP. Conclusion: High resistance rates to quinolones were observed not only for in-patients but also for out-patients with urinary tract enterobacterial infections. These findings demonstrate the importance of antibiotics susceptibility testing in improving quinolones prescription practices in Cameroon

Global assessment of dengue Virus-Specific CD4+ T cell responses in Dengue-Endemic areas

Background: Dengue is a major public health problem worldwide. Assessment of adaptive immunity is important to understanding immunopathology and to define correlates of protection against dengue virus (DENV). To enable global assessment of CD4+ T cell responses, we mapped HLA-DRB1-restricted DENV-specific CD4+ T cell epitopes in individuals previously exposed to DENV in the general population of the dengue-endemic region of Managua, Nicaragua. Methods: HLA class II epitopes in the population of Managua were identified by an in vitro IFNγ ELISPOT assay. CD4+ T cells purified by magnetic bead negative selection were stimulated with HLA-matched epitope pools in the presence of autologous antigen-presenting cells, followed by pool deconvolution to identify specific epitopes. The epitopes identified in this study were combined with those previously identified in the DENV endemic region of Sri Lanka, to generate a “megapool” (MP) consisting of 180 peptides specifically designed to achieve balanced HLA and DENV serotype coverage. The DENV CD4MP180 was validated by intracellular cytokine staining assays. Results: We detected responses directed against a total of 431 epitopes, representing all 4 DENV serotypes, restricted by 15 different HLA-DRB1 alleles. The responses were associated with a similar pattern of protein immunodominance, overall higher magnitude of responses, as compared to what was observed previously in the Sri Lanka region. Based on these epitope mapping studies, we designed a DENV CD4 MP180 with higher and more consistent coverage, which allowed the detection of CD4+ T cell DENV responses ex vivo in various cohorts of DENV exposed donors worldwide, including donors from Nicaragua, Brazil, Singapore, Sri Lanka, and U.S. domestic flavivirus-naïve subjects immunized with Tetravalent Dengue Live-Attenuated Vaccine (TV005). This broad reactivity reflects that the 21 HLA-DRB1 alleles analyzed in this and previous studies account for more than 80% of alleles present with a phenotypic frequency ≥5% worldwide, corresponding to 92% phenotypic coverage of the general population (i.e., 92% of individuals express at least one of these alleles). Conclusion: The DENV CD4 MP180 can be utilized to measure ex vivo responses to DENV irrespective of geographical location

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Influence du substrat sur l\'isolement et la croissance radiale de Trachysphaera fructigena, agent de la maladie du bout de cigare des Musacées

La maladie du bout de cigare est une affection parasitaire des fruits des Musacées principalement causée par Trachysphaera fructigena au Cameroun. Cette maladie saisonnière sévit dans les régions de moyenne à hautes altitudes (400-2000 m). Bien qu\'elle ait été depuis longtemps signalée au Cameroun, très peu de travaux lui ont été consacrés. Cette étude a pour objectifs de déterminer les conditions d\'isolement du pathogène et d\'identifier les milieux de culture permettant une production abondante et rapide du mycélium. Les fruits infectés ont été récoltés dans différentes zones de culture de bananiers. La croissance radiale de 3 souches obtenues a été évaluée sur 14 milieux de culture à 20°C. L\'isolement de T. fructigena ne semble être possible que sur les jeunes fruits n\'ayant pas encore atteint leur maturité physiologique, et sur les fruits contaminés dans les sites de stockage. Le milieu V8 et ceux faits à base de pomme de terre, de pulpe de banane, plantain, et papaye sont respectivement les meilleurs pour la croissance radiale après 4 à 7 jours d\'incubation. Ces résultats permettront de faciliter l\'isolement et une production abondante et rapide du mycélium de T. fructigena en vue des études sur sa biologie et ses interactions avec l\'hôte.Cigar-end disease is an affection of Musaceae fruits mainly caused by the fungus Trachysphaera fructigena in Cameroon. The disease occurs in areas of average to high altitudes (400-2000 m above the sea level). Although the disease has been identified in Cameroon long time ago, few research works have been done on this fungus. The purpose of this study is to determine the conditions of isolation of the pathogen and to identify culture media which allow the fungus to rapidly grow and produce large quantity of mycelium. The infected fruits from which the fungus was isolated were harvested in different banana culture areas. Radial growth of 3 single isolates obtained was evaluated on 14 culture media at 20°C. The isolation of T. fructigena seems to be possible only from young infected fruits at their early stage of development, and from fruits contaminated in storage rooms. V8 medium and media prepared with potato juice, banana, plantain and papaw pulps were the best for radial growth after 4 to 7 days of incubation. These results will make it easy to isolate T. fructigena and rapidly produce large amount of its mycelium for studies related to its biology and interactions with the host. Keywords: Maladie du bout de cigare, Musacées, Milieux de culture, Trachysphaera fructigena ; Croissance radiale. Cigar-end disease; Musaceae; Culture media, Trachysphaera fructigena; Radial growth. CaJEB Vol. 3 (2) 2007: pp. 103-11

Human Leucocyte Antigen Class I Diversity among Human Immunodeficiency Virus Exposed Negative and Positive Children in Cameroon.

The link between HLA types and HIV disease progression has been well established with alleles and residues associated to progression or non-progression to AIDS. Vertical transmission rate of HIV in Cameroon is still very high (10%). The aim of this study was to describe the diversity of HLA class I in infants born to HIV infected mothers and to determine the influence of HLA genotype in mother to child HIV transmission in Cameroon. Thirty four HIV infected infants and 28 HIV exposed but non infected infants born to HIV-positive mothers were enrolled in this study. HLA-A, HLA-B, group allele frequencies were determined by low-resolution polymerase chain reaction using sequencespecific primers. Nineteen HLA-A, 20 HLA-B allelic groups were identified in the study population. Among all the allelic variants identified, only HLA-B*44 allelic frequency resulted significantly increased in exposed non infected children (12.5% in exposed non infected versus 2.9% in exposed HIV-infected children, p=0.04). HLA-B*44 may be associated with the resistance to HIV infection upon mother to child exposure

Expression profiles of miR3181 and miR199a in plasma and placenta of virally suppressed HIV-1 infected Cameroonian pregnant women at delivery.

Human immunodeficiency virus (HIV)-1 infection during pregnancy reduces the transplacental transfer of protective maternal antibodies needed to confer immunity during early postnatal life. However, the mediation of MicroRNA in this dysregulation is not well understood MicroRNAs 3181 and 199a have been shown to mediate neonatal Fc receptor (FcRn)-like transmembrane antibody transfer and endocytosis respectively but their expression levels in the placenta and plasma in women living with HIV have not been extensively investigated. The objective of this study was to determine how the expression levels of miR-3181 and miR-199a in the placenta and plasma are affected in women chronically infected with HIV who are on antiretroviral therapy (ART) and are virally suppressed at delivery. In this pilot case-control study, plasma and placenta biopsies were obtained from 36 (18 HIV+ and 18 HIV-) Cameroonian women at delivery. MicroRNAs 3181 and 199a expression levels were measured using RT-qPCR, data was analyzed using SPSS22.0 and R 3.60, and p values below 0.05 were considered statistically significant. All the HIV-infected women were on known ART regimens and were virally suppressed. There was no significant difference in the levels of miR-3181 (p>0.05) in the placenta and plasma amongst HIV-infected and HIV uninfected women. The expression levels of miR-199a were significantly greater in the plasma compared to the placenta of HIV+ (p = 0.00005) and HIV- (p = 0.027) women. Moreover, there was a significantly higher (p = 0.02) level of miR-199a in the plasma of women with HIV and their uninfected counterparts. Linear regression models adjusted for systolic pressure showed no significant difference (p>0.05) in the levels of miR-199a and miR-3181 in both the placenta and plasma due to HIV infection. Our findings suggest that even though ART uptake and viral suppression might help in maintaining miR3181 and miR199a levels in the placenta of women with HIV at comparative levels to those of their HIV negative counterparts, the significantly higher levels of miR-199a in the plasma of women with HIV compared to the placenta might highlight lurking systemic dangers and requires further investigation

MicroRNA hsa-miR-29a-3p is a plasma biomarker for the differential diagnosis and monitoring of tuberculosis

The diagnosis of tuberculosis (TB) continues to pose substantial public health problems. The quest for diagnostic biomarkers for TB is therefore primordial. This study aimed to evaluate the diagnostic and anti-TB treatment monitoring potentials of some selected miRNAs. Quantitative real time polymerase chain reaction and Receiver operating characteristics were used to estimate the ability of miRNAs to discriminate between healthy controls (HEC), latent (LTB) and active TB (ATB). The study showed that: hsa-miR-29a-3p, hsa-miR-155-5p and hsa-miR-361-5p were significantly upregulated in ATB compared to HEC while hsa-miR-29a-3p, and hsa-miR-361-5p were also significantly up-regulated in ATB compared to LTB (all P 64 0.05). MiR-29a-3p showed a good (81.37%) distinguishing performance in discriminating ATB from HEC and a good (84.35%) diagnostic performance in discriminating ATB from LTB. The performance of miR-29a-3p present in the blood in discriminating active TB from latent TB and healthy controls indicates it may be a useful biomarker for diagnosis of TB. Because this miRNA is found in blood (plasma) which is easy to collect compared to sputum it could be used in pediatric and extra-pulmonary TB cases

Global assessment of dengue virus-specific CD4+ T Cell responses in dengue-endemic areas

10.3389/fimmu.2017.01309Frontiers in Immunology8OCT130