title: Antibacterial and antibiotic potentiating activities of tropical marine sponge extracts.
abstract: Increasing prevalence of antibiotic resistance has led research to focus on discovering new antimicrobial agents derived from the marine biome. Although ample studies have investigated sponges for their bioactive metabolites with promising prospects in drug discovery, the potentiating effects of sponge extracts on antibiotics still remains to be expounded. The present study aimed to investigate the antibacterial capacity of seven tropical sponges collected from Mauritian waters and their modulatory effect in association with three conventional antibiotics namely chloramphenicol, ampicillin and tetracycline. Disc diffusion assay was used to determine the inhibition zone diameter (IZD) of the sponge total crude extracts (CE), hexane (HF), ethyl acetate (EAF) and aqueous (AF) fractions against nine standard bacterial isolates whereas broth microdilution method was used to determine their minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs) and antibiotic potentiating activity of the most active sponge extract. MIC values of the sponge extracts ranged from 0.039 to 1.25mg/mL. Extracts from Neopetrosia exigua rich in beta-sitosterol and cholesterol displayed the widest activity spectrum against the 9 tested bacterial isolates whilst the best antibacterial profile was observed by its EAF particularly against Staphylococcus aureus and Bacillus cereus with MIC and MBC values of 0.039mg/mL and 0.078mg/mL, respectively. The greatest antibiotic potentiating effect was obtained with the EAF of N. exigua (MIC/2) and ampicillin combination against S. aureus. These findings suggest that the antibacterial properties of the tested marine sponge extracts may provide an alternative and complementary strategy to manage bacterial infections.
authors.affiliation: Department of Biosciences, Faculty of Science, University of Mauritius, Réduit 80837, Republic of Mauritius; ANDI Centre of Excellence for Biomedical and Biomaterials Research, MSIRI Building, University of Mauritius, Réduit 80837, Republic of Mauritius; Department of Health Sciences, Faculty of Science University of Mauritius, Réduit, Republic of Mauritius.
authors.forename: Rima
authors.initials: R
authors.lastname: Beesoo
authors.affiliation: Department of Marine and Ocean Science, Fisheries and Mariculture, Faculty of Ocean Studies, University of Mauritius, Réduit 80837, Republic of Mauritius. Electronic address: r.bhagooli@uom.ac.mu.
authors.forename: Ranjeet
authors.initials: R
authors.lastname: Bhagooli
authors.affiliation: ANDI Centre of Excellence for Biomedical and Biomaterials Research, MSIRI Building, University of Mauritius, Réduit 80837, Republic of Mauritius; Department of Health Sciences, Faculty of Science University of Mauritius, Réduit, Republic of Mauritius. Electronic address: v.neergheen@uom.ac.mu.
authors.forename: Vidushi S
authors.initials: VS
authors.lastname: Neergheen-Bhujun
authors.affiliation: Guy Hilton Research Centre, Institute for Science and Technology in Medicine, Keele University, Thornburrow Drive, ST4 7 QB Stoke on Trent, UK.
authors.forename: Wen-Wu
authors.initials: WW
authors.lastname: Li
authors.affiliation: Synthetic Epigenetics Laboratory, MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital Crewe Road South, Edinburgh EH4 2XU, UK.
authors.forename: Alexander
authors.initials: A
authors.lastname: Kagansky
authors.affiliation: ANDI Centre of Excellence for Biomedical and Biomaterials Research, MSIRI Building, University of Mauritius, Réduit 80837, Republic of Mauritius. Electronic address: tbahorun@uom.ac.mu.
authors.forename: Theeshan
authors.initials: T
authors.lastname: Bahorun
mesh_terms: D000085:Acetates / Q000737:chemistry; D000667:Ampicillin / Q000819:agonists / Q000494:pharmacology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D059001:Aquatic Organisms / Q000737:chemistry* / Q000254:growth & development; D001688:Biological Products / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D002701:Chloramphenicol / Q000819:agonists / Q000494:pharmacology; D052978:Disk Diffusion Antimicrobial Tests; D054313:Drug Agonism; D055808:Drug Discovery; D024881:Drug Resistance, Bacterial / Q000187:drug effects; D006090:Gram-Negative Bacteria / Q000187:drug effects / Q000254:growth & development; D006094:Gram-Positive Bacteria / Q000187:drug effects / Q000254:growth & development; D019156:Indian Ocean; D008436:Mauritius; D008826:Microbial Sensitivity Tests; D011161:Porifera / Q000737:chemistry* / Q000254:growth & development; D012855:Sitosterols / Q000032:analysis / Q000302:isolation & purification / Q000494:pharmacology; D012997:Solvents / Q000737:chemistry; D013752:Tetracycline / Q000819:agonists / Q000494:pharmacology
chemical_list: D000085:Acetates; D000900:Anti-Bacterial Agents; D001688:Biological Products; D012855:Sitosterols; D012997:Solvents; C025473:gamma-sitosterol; D002701:Chloramphenicol; C007650:ethyl acetate; D000667:Ampicillin; D013752:Tetracycline
keywords: Antibacterial activity; Antibiotic potentiating; Marine sponges; Mauritius; Neopetrosia exigua