7 research outputs found

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

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    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

    Characterisation of Extended-Spectrum β-Lactamases among Multidrug Resistant Enterobacteriaceae from Sudan

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    The aim of the present study was to characterize extended-spectrum β-lactamase (ESBLs) genes in multidrug resistant enterobacterial pathogens as well as commensal isolates from the Sudan during the period 2003 to 2007. ESBL production was determined phenotypically by the combined disc method, and was characterized genotypically by the detection of blagenes by PCR and nucleotide sequencing. Transferability was examined by conjugation with nalidixic-acid resistant E. coli K12. The results showed that a total of 106 of the 113 (94%) isolates including E. coli, Klebsiella pneumoniae, proteus spp., Enterobacter cloacae, Providencia spp. and Morganella morganii, were positive for blagenes including the prototype blaTEM. Eleven isolates (28%) of the 113 were ESBL producers encoding blaSHV genes (SHV5, SHV5a, SHV12, SHV26, SHV28 and SHV38), 90 isolates (80%) were CTX-M positive. All, but only one (CTX-M9) were CTX-M15. Only 3(2.7%) of the isolates were Amp-C producers (CMY-4 and DHA-1). Plasmid transfer of the multiple resistance patterns was achieved among all the isolates. These findings demonstrated that ESBLs were highly produced by multi-resistant enterobacterial isolates from the Sudan; among both clinical pathogens as well as stool commensals. This is the first report of ESBLs genes characterization from the Sudan

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