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Demisie S, Oh DC, Wolday D, Rinke de Wit TF, Abera A, Tasew G, Shenkutie AM, Girma S, Tafess K. Diversity of culturable bacterial isolates and their potential as antimicrobial against human pathogens from Afar region, Ethiopia. Microbiol Spectr 2024:e0181024. [PMID: 39365108 DOI: 10.1128/spectrum.01810-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2024] [Accepted: 09/15/2024] [Indexed: 10/05/2024] Open
Abstract
Antimicrobial resistance is a growing global concern exacerbated by the scarcity of new medications and resistance to current antibiotics. Microbes from unexplored habitats are promising sources of natural products to combat this challenge. This study aimed to isolate bacteria producing secondary metabolites and assess their antimicrobial efficacy against human pathogens. Soil and liquid samples were collected from Afar region, Ethiopia. Bacterial isolates were obtained using standard serial dilution techniques. Antimicrobial activity was evaluated using agar plug and well diffusion methods. matrix-assisted laser desorption/ionization time-of-flight-mass spectrometry (MALDI-TOF MS) and whole-genome sequencing (WGS) were conducted for the isolate exhibiting the highest antimicrobial activity. Secondary metabolites were extracted and analyzed using gas chromatography-mass spectra (GC-MS). In this study, 301 bacteria isolates were identified, of which 68 (22.6%) demonstrated antagonistic activity against at least one reference pathogen. Whole-genome sequencing revealed that Sl00103 belongs to the genus Bacillus, designated as Bacillus sp. Sl00103. The extract of Sl00103 showed zones of inhibition ranging between 17.17 ± 0.43 and 26.2 ± 0.4 mm against bacterial pathogens and 19.5 ± 0.44 to 21.0 ± 1.01 mm against Candida albicans. GC-MS analysis of ethyl acetate and n-hexane extracts identified major compounds including (R,R)-butane-2,3-diol; 3-isobutylhexahydropyrrolo[1,2a] pyrazine-1,4-dione; cyclo(L-prolyl-L-valine); and tetradecanoic acid, 12-methyl-, methyl ester; hexadecanoic acid, methyl ester among other. In conclusion, this study isolated several promising bacterial strains from the Afar region in Ethiopia, with strain Sl00103 (Bacillus sp. Sl00103) demonstrating notable antimicrobial and antioxidant activities and warranting further studies. IMPORTANCE Antimicrobial resistance (AMR) is an escalating global health threat affecting humans, animals, and the environment, underscoring the urgent need for alternative pathogen control methods. Natural products, particularly secondary metabolites from bacteria, continue to be a vital source of antibiotics. However, microbial habitats and metabolites in Africa remain largely unexplored. In this study, we isolated and screened bacteria from Ethiopia's Afar region, characterized by extreme conditions like high temperatures, volcanic activity, high salinity, and hot springs to identify potential bioactive compounds. We discovered diverse bacterial isolates with antimicrobial activity against various pathogens, including strain Sl00103 (Bacillus sp. Sl00103), which demonstrated significant antimicrobial and antioxidant activities. GC-MS analysis identified several antimicrobial compounds, highlighting strain Sl00103 as a promising source of secondary metabolites with potential pharmaceutical applications and warranting further investigation.
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Affiliation(s)
- Sisay Demisie
- Department of Applied Biology, School of Applied Natural Science, Adama Science and Technology University, Adama, Ethiopia
| | - Dong-Chan Oh
- Natural Products Research Institute, College of Pharmacy, Seoul National University, Seoul, South Korea
| | - Dawit Wolday
- Depatment of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Tobias F Rinke de Wit
- Department of Global Health, Amsterdam Institute for Global Health and Development (AIGHD), Amsterdam University Medical Centre, University of Amsterdam, Amsterdam, the Netherlands
| | - Adugna Abera
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Geremew Tasew
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong, China
| | - Abebe Mekuria Shenkutie
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong, China
| | - Sisay Girma
- College of Veterinary Medicine and Agriculture, Addis Ababa University, Bishoftu, Ethiopia
- Institute for Microbiology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Ketema Tafess
- Department of Applied Biology, School of Applied Natural Science, Adama Science and Technology University, Adama, Ethiopia
- Institute of Pharmaceutical Sciences, Adama Science and Technology University, Adama, Ethiopia
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Freitas-Silva J, de Oliveira BFR, Vigoder FDM, Muricy G, Dobson ADW, Laport MS. Peeling the Layers Away: The Genomic Characterization of Bacillus pumilus 64-1, an Isolate With Antimicrobial Activity From the Marine Sponge Plakina cyanorosea (Porifera, Homoscleromorpha). Front Microbiol 2021; 11:592735. [PMID: 33488540 PMCID: PMC7820076 DOI: 10.3389/fmicb.2020.592735] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 12/09/2020] [Indexed: 11/30/2022] Open
Abstract
Bacillus pumilus 64-1, a bacterial strain isolated from the marine sponge Plakina cyanorosea, which exhibits antimicrobial activity against both pathogenic and drug-resistant Gram-positive and Gram-negative bacteria. This study aimed to conduct an in-depth genomic analysis of this bioactive sponge-derived strain. The nearly complete genome of strain 64-1 consists of 3.6 Mbp (41.5% GC), which includes 3,705 coding sequences (CDS). An open pangenome was observed when limiting to the type strains of the B. pumilus group and aquatic-derived B. pumilus representatives. The genome appears to encode for at least 12 potential biosynthetic gene clusters (BGCs), including both types I and III polyketide synthases (PKS), non-ribosomal peptide synthetases (NRPS), and one NRPS-T1PKS hybrid, among others. In particular, bacilysin and other bacteriocin-coding genes were found and may be associated with the detected antimicrobial activity. Strain 64-1 also appears to possess a broad repertoire of genes encoding for plant cell wall-degrading carbohydrate-active enzymes (CAZymes). A myriad of genes which may be involved in various process required by the strain in its marine habitat, such as those encoding for osmoprotectory transport systems and the biosynthesis of compatible solutes were also present. Several heavy metal tolerance genes are also present, together with various mobile elements including a region encoding for a type III-B Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) region, four prophage segments and transposase elements. This is the first report on the genomic characterization of a cultivable bacterial member of the Plakina cyanorosea holobiont.
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Affiliation(s)
- Jéssyca Freitas-Silva
- Institute of Microbiology Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Bruno Francesco Rodrigues de Oliveira
- Institute of Microbiology Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,School of Microbiology, University College Cork, Cork, Ireland
| | - Felipe de Mello Vigoder
- Department of Genetics, Institute of Biology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Guilherme Muricy
- Department of Invertebrates, National Museum, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Alan D W Dobson
- School of Microbiology, University College Cork, Cork, Ireland.,Environmental Research Institute, University College Cork, Cork, Ireland
| | - Marinella Silva Laport
- Institute of Microbiology Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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