Genomic characterization of SARS-CoV-2 in Guinea, West Africa.

SARS-CoV-2 has claimed several million lives since its emergence in late 2019. The ongoing evolution of the virus has resulted in the periodic emergence of new viral variants with distinct fitness advantages, including enhanced transmission and immune escape. While several SARS-CoV-2 variants of concern trace their origins back to the African continent-including Beta, Eta, and Omicron-most countries in Africa remain under-sampled in global genomic surveillance efforts. In an effort to begin filling these knowledge gaps, we conducted retrospective viral genomic surveillance in Guinea from October 2020 to August 2021. We found that SARS-CoV-2 clades 20A, 20B, and 20C dominated throughout 2020 until the coincident emergence of the Alpha and Eta variants of concern in January 2021. The Alpha variant remained dominant throughout early 2021 until the arrival of the Delta variant in July. Surprisingly, despite the small sample size of our study, we also found the persistence of the early SARS-CoV-2 clade 19B as late as April 2021. Together, these data help fill in our understanding of the SARS-CoV-2 population dynamics in West Africa early in the COVID-19 pandemic.

Metabolic and Immune Consequences of Antibiotic Related Microbiome Alterations during first-line Tuberculosis Treatment in Bamako, Mali.

Background: Tuberculosis (TB) infection is known to lead to the unbalance of the gut microbiota and act synergistically on the decline of the host immune response, when untreated. Moreover, previous work has found a correlation between dysbiosis in the gut microbiota composition and the use of antibiotics. However, there is a need for an in-depth understanding of the metabolic and immune consequences of antibiotic-related microbiome alterations during first-line TB treatment. Methods: In a longitudinal cohort study, which included TB-infected cohorts and healthy individuals (control group), we studied the anti-TB-related changes in the gut microbiota composition and related functional consequences. Sputum, whole blood and stool samples were collected from participants at four time-points including before (Month-0), during (Month-2), at the end of drug treatment (Month-6) and 9 months after treatment (Month-15). Controls were sampled at inclusion and Month-6. We analyzed the microbiota composition and microbial functional pathways with shotgun metagenomics, analyzed the blood metabolomics using high-performance liquid chromatography (HPLC), and measured the levels of metabolites and cytokines with cytometric bead array. Results: We found that the gut microbiota of patients infected with TB was different from that of the healthy controls. The gut microbiota became similar to healthy controls after treatment but was still significantly different after 6 months treatment and at the follow up 9 months after treatment. Our data also showed disturbance in the plasma metabolites such as tryptophan and tricarboxylic acids components of patients during TB treatment. Levels of IL-4, IL-6, IL-10, and IFN-γ decreased during treatment and levels were maintained after treatment completion, while IL-17A known to have a strong link with the gut microbiota was highly expressed during treatment period and longer than the 9-month post treatment completion. We found that some fatty acids were negatively correlated with the abundance of taxa. For example, Roseburia, Megasphaera, and alpha proteobacterium HIMB5 species were negatively correlated (rho = -0.6) with the quinolinate production. Conclusion: Changes in the composition and function of gut microbiota was observed in TB patients before and after treatment compared to healthy controls. The differences persisted at nine months after treatment completion. Alterations in some bacterial taxa were correlated to the changes in metabolite levels in peripheral blood, thus the altered microbial community might lead to changes in immune status that influence the disease outcome and future resistance to infections.

Use of light-emitting diode fluorescence microscopy to detect acid-fast bacilli in sputum as proficient alternative tool in the diagnosis of pulmonary tuberculosis in countries with limited resource settings.

Background: Despite recent advances in the development of more sensitive technologies for the diagnosis of tuberculosis (TB), in resource-limited settings, the diagnosis continues to rely on sputum smear microscopy. This is because smear microscopy is simple, cost-efficient and the most accessible tool for the diagnosis of TB. Our study evaluated the performance of light-emitting diode fluorescence microscopy (LED-FM) using auramine/rhodamine (auramine) and the fluorescein di-acetate (FDA) vital stain in the diagnostic of pulmonary TB in Bamako, Mali. Methods: Sputum smear microscopy was conducted using the FDA and auramine/rhodamine staining procedures on fresh samples using LED-FM to evaluate the Mycobacterium TB (MTB) metabolic activity and to predict contagiousness. Mycobacterial culture assay was utilized as a gold standard method. Results: Out of 1401 TB suspected patients, 1354 (96.65%) were retrieved from database, which were MTB complex culture positive, and 47 (3.40%) were culture negative (no mycobacterial growth observed). Out of the 1354 included patients, 1343 (95.86%), were acid-fast bacillus (AFB) positive after direct FDA staining, 1352 (96.50%) AFB positive after direct Auramine, and 1354 (96.65%) AFB positive with indirect auramine after digestion and centrifugation. Overall, the FDA staining method has a sensitivity of 98.82%, while the sensitivity of Auramine with direct observation was 99.48%, and 99.56% with the indirect examination. Conclusion: This study showed that, using fresh sputum both auramine/rhodamine and FDA are highly sensitive methods in diagnosing pulmonary TB and could be easily used in countries with limited resource settings.

Prevalence and Clinical Relevance of Schistosoma mansoni Co-Infection with Mycobacterium tuberculosis: A Systematic Literature Review.

Tuberculosis disease stands for the second leading cause of death worldwide after COVID-19, most active tuberculosis cases result from the reactivation of latent TB infection through impairment of immune response. Several factors are known to sustain that process. Schistosoma mansoni, a parasite of the helminth genus that possesses switching power from an immune profile type Th1 to Th2 that favors reactivation of latent TB bacteria. The aim of the study was to assess the prevalence of the co-infection between the two endemic infections. Systematic literature was contacted at the University Clinical Research Center at the University of Sciences, Techniques, and Technologies of Bamako in Mali. Original articles were included, and full texts were reviewed to assess the prevalence and better understand the immunological changes that occur during the co-infection. In total, 3530 original articles were retrieved through database search, 53 were included in the qualitative analysis, and data from 10 were included in the meta-analysis. Prevalence of the co-infection ranged from 4% to 34% in the literature. Most of the articles reported that immunity against infection with helminth parasite and more specifically Schistosoma mansoni infection enhances latent TB reactivation through Th1/Th2. In sum, the impact of Schistosoma mansoni co-infection with Mycobacterium tuberculosis is under-investigated. Understanding the role of this endemic tropical parasite as a contributing factor to TB epidemiology and burden could help integrate its elimination as one of the strategies to achieve the END-TB objectives by the year 2035.

Genomic analysis of methicillin-resistant Staphylococcus aureus isolated from poultry and occupational farm workers in Umgungundlovu District, South Africa.

This study detected methicillin-resistant Staphylococcus aureus (MRSA) isolates circulating in poultry and farm workers at an intensive poultry production system in uMgungundlovu, South Africa and established the genetic relatedness and characteristics of the isolates using whole genome sequencing (WGS). A total of 145 S. aureus were isolated from poultry (120) and occupational workers (25) in the "farm to fork" continuum (farm, transport, slaughterhouse, and retail points). Twelve MRSA (12/145; 8.3%) isolates were found in the poultry food-chain. MRSA isolates were subjected to antibiotic susceptibility testing against a panel of 20 antibiotics using the broth dilution method and their whole genome was sequenced via the Illumina MiSeq. All the MRSA isolates were multi-drug resistant (MDR) and carried the mecA gene on the SCCmec mobile genetic element (MGE). The majority (11/12) of the MRSA isolates circulating between humans and animals in the continuum belonged to a human-associated clone, ST612-CC8-t1257-SCCmec_IVd (2B), previously reported in South Africa. Other MGEs present in the isolates included: plasmid replicons based on Rep 7 and 20, insertion sequences (IS1182), and prophages (phi2958PVL). Genomic analysis identified a distinct acquired antibiotic resistome in the clone, which accurately predicted the phenotypic antibiograms. Phylogenetic analysis clustered the isolates within the major cluster (I), suggesting the spread of the local dominant multidrug resistance MRSA clone ST612-CC8-t1257-SCCmec_IVd (2B) between humans and animals along the 'farm to fork' continuum. The findings of this study suggest the need to establish appropriate control measures to curb the spread of MDR-MRSA in the food chain.