SARS-CoV-2 across Africa: The impact of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has been hard to track in African countries, largely because of patchy data. Wilkinson et al . curated viral genomes collected in 2021 from several countries across the continent. Outbreaks during 2020 in each African country were initiated by imported cases, mostly from Europe. As the pandemic developed, case numbers in African countries were likely many times higher than reported, and subsequent waves of the pandemic appear to have been more severe. Consequently, high-transmission variants have emerged that have spread within the continent, and African countries must be included in global control efforts. —CA

Among the numerous variants of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) that have been reported worldwide, the emergence of the Omicron variant has drastically changed the landscape of the coronavirus disease (COVID-19) pandemic. Here, we analyzed the genetic diversity of Moroccan SARS-CoV-2 genomes with a focus on Omicron variant after one year of its detection in Morocco in order to understand its genomic dynamics, features and its potential introduction sources. From 937 Omicron genomes, we identified a total of 999 non-unique mutations distributed across 92 Omicron lineages, of which 13 were specific to the country. Our findings suggest multiple introductory sources of the Omicron variant to Morocco. In addition, we found that four Omicron clades are more infectious in comparison to other Omicron clades. Remarkably, a clade of Omicron is particularly more transmissible and has become the dominant variant worldwide. Moreover, our assessment of Receptor-Binding Domain (RBD) mutations showed that the Spike K444T and N460K mutations enabled a clade higher ability of immune vaccine escape. In conclusion, our analysis highlights the unique genetic diversity of the Omicron variant in Moroccan SARS-CoV-2 genomes, with multiple introductory sources and the emergence of highly transmissible clades. The distinctiveness of the Moroccan strains compared to global ones underscores the importance of ongoing surveillance and understanding of local genomic dynamics for effective response strategies in the evolving COVID-19 pandemic.

Background: Aggregatibacter actinomycetemcomitans is a Gram-negative, facultative anaerobic, immobile oral bacterium responsible for the secretion of virulence factors, namely leukotoxin (LtxA), a large exotoxin of the RTX family that enables the bacterium to evade the immune system by destroying leukocytes, resulting in aggressive periodontitis (AP) leading to tooth loss. Methods: This study aimed to screen 106 molecules derived from Moroccan propolis in order to identify potential inhibitors of the active sites of LtxA based on molecular docking, ADMET property evaluation, and molecular dynamics (MD) simulation. Results: Epigallocatechin gallate (EGCg), used as a reference compound, showed binding energies of −6.9 kcal/mol, −6.1 kcal/mol, −6.5 kcal/mol, and −5.9 kcal/mol with the four active sites P1, P2, P3, and P4, respectively. By establishing conventional hydrogen bonds, pi-alkyl bonds, and non-covalent pi–pi bonds. Chrysin and luteolin showed favorable binding affinities with the four active sites, named as follows: P1–P4 (P1–chrysin = −7.5 kcal/mol; P2–chrysin = −7.9 kcal/mol; P3–chrysin = −8.1 kcal/mol; P4–chrysin = −6.9 kcal/mol; P1–luteolin = −7.3 kcal/mol; P2–luteolin = −7.6 kcal/mol; P3–luteolin = −8.1 kcal/mol; P4–luteolin = −7.3 kcal/mol). The binding affinity of these two propolis derivatives was stabilized by pi−sigma bonds, pi−alkyl bonds, conventional hydrogen bonds, pi-cation interactions, non-covalent pi–pi bonds, and carbon–hydrogen bonds. According to free energy calculations performed with Prime MM-GBSA, the complexes formed by chrysin demonstrated the most stable interactions due to Van der Waals and lipophilic forces. Luteolin formed significant interactions, but slightly weaker than those of chrysin. These results reveal the inhibitory potential of chrysin and luteolin with protein active sites. MD simulations corroborated the excellent stability of complexes formed by chrysin, as indicated by low RMSD values, suggesting favorable dynamic behavior. Conclusions: These results highlight the potential of chrysin as a versatile inhibitor capable of interacting with the four active sites. These findings are a strong foundation for further experimental confirmations.

Introduction: Since the COVID-19 pandemic began in December 2019, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has continuously evolved with many variants of concern emerging across the world. Methodology: In order to monitor the evolution of these variants in Morocco, we analyzed a total of 2130 genomes of the delta variant circulating around the world. We also included 164 Moroccan delta variant sequences in our analysis. Results: Our findings suggest at least four introductions from multiple international sources and a rise of a dominant delta sub-lineage AY.33 in Morocco. Moreover, we report three mutations in the N-terminal domain of the S protein specific to the Moroccan AY.33 isolates, T29A, T250I and T299I. The effect of these mutations on the secondary structure and the dynamic behavior of the S protein N-terminal domain was further determined. Conclusions: We conclude that these mutations might have functional consequences on the S protein of SARS-CoV-2.

Here, we report the near-complete genome sequence and the genetic variations of a clinical sample of SARS-CoV-2 harboring the N501Y mutation assigned to the B.1.1.7 lineage. The sample was collected from a nasopharyngeal swab of a female patient from Temara, Morocco, and the sequencing was done using Ion S5 technology.

Aptamers, short nucleic acid sequences with high specificity and affinity for their targets, are promising candidates for diagnostic applications due to their ability to detect a wide range of pathogens. We present a fluorescent bioimaging approach for detecting Pseudomonas aeruginosa , based on aptamer F23. Conjugated with fluorescent dye, its detection efficacy was evaluated on 15 Gram‐negative and ‐positive bacteria, including fixed and live cells, as homogeneous and heterogeneous populations. We developed an automated, open‐access software for quantifying microscopy images. Its high sensitivity enables accurate quantification of bacteria labeled with aptamers. For example, it successfully detected 1122 P. aeruginosa cells labeled with aptamer F23 out of a total of 1123 P. aeruginosa cells in a single image. With 200,000 analyzed bacteria, we demonstrated that the aptamer effectively detects various reference and clinical strains of P. aeruginosa , while failing to detect Gram‐positive Staphylococcus aureus , Staphylococcus haemolyticus , Staphylococcus epidermidis , and Corynebacterium striatum , as well as Gram‐negative Klebsiella pneumoniae , Acinetobacter baumannii , and Escherichia coli . This aptamer is therefore a promising tool to distinguish P. aeruginosa from different strains of the skin microbiota. However, our quantitative method also revealed partial labeling to other bacterial cells, highlighting the issue of refining aptamer selection to improve selectivity.