scholarly journals Antagonistic Potential of Soil Streptomyces Isolates from Southern Thailand to Inhibit Foodborne Bacterial Pathogens

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Waenurama Chemoh ◽  
Wahida Bin-Ismail ◽  
Sawitree Dueramae
Keyword(s):  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Bacterial Pathogens ◽  
Antagonistic Activity ◽  
Rrna Gene ◽  
Rice Soils ◽  
Streptomyces Species ◽  
Genus Streptomyces ◽  
Crude Extracts ◽  
Broth Microdilution Method

Streptomyces are well known for their competence to produce thousands of bioactive secondary metabolites and enzymes. This study aimed to assess the inhibitory activities of crude extracts from diverse Streptomyces collected from rice soils in Narathiwat, Thailand, against foodborne bacterial pathogens. In total, 136 Actinomycete isolates were screened using a cross-streak method for the ability to produce effective metabolites against 5 pathogenic bacteria. Out of these, 19 (13.97%) isolates had antibacterial activity against at least one tested bacterium. Most of the isolates could strongly suppress the growth of S. aureus ATCC25923 and B. cereus MTCC430 except P. aeruginosa ATCC27853. On the basis of morphological, cultural, and biochemical characteristics, all potent isolates exhibited typical features that fitted the genus Streptomyces. Two of the 7 selected ethyl acetate crude extracts had good antagonistic activity against S. aureus ATCC25923 and B. cereus MTCC430 when tested using the agar well diffusion assay. Furthermore, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of the 2 extracts evaluated using the colorimetric broth microdilution method ranged from 256 to >1,024 μg/ml against the tested bacteria. The partial nucleotide sequences of the 16S rRNA gene led to identifying both active isolates as Streptomyces species. These active Streptomyces isolates could provide an interesting source for generating innumerable natural compounds with antibacterial activity that can presumably be developed to fight bacterial pathogens in the near future.

scholarly journals Antagonistic activity of terrestrial Streptomyces sp. VITNK9 against Gram negative bacterial pathogens affecting the fish and shellfish in aquaculture

2018 ◽  
Vol 53 (2) ◽  
pp. 171 ◽  
Author(s):  
Mohammed Ishaque Nabila ◽  
Krishnan Kannabiran
Keyword(s):  
Antibacterial Activity ◽  
Ethyl Acetate ◽  
Vibrio Harveyi ◽  
Bacterial Pathogens ◽  
Vibrio Anguillarum ◽  
Antagonistic Activity ◽  
Edwardsiella Tarda ◽  
Streptomyces Sp ◽  
Aeromonas Caviae ◽  
Fish And Shellfish

A total of 72 morphologically different actinomycetes isolates were isolated from samples collected at different regions of Vellore, Tamil Nadu, India and screened for its antibacterial activity against fish and shellfish pathogens. All actinomycetes isolates were screened for antibacterial activity by cross streak method against the selected fish and shellfish bacterial pathogens including Aeromonas caviae, Aeromonas hydroplila, Edwardsiella tarda, Vibrio anguillarum and Vibrio harveyi. Secondary screening of antagonistic isolates by well diffusion method leads to the identification of potential isolate. Culture conditions for the potential isolate were optimized for maximal growth and yield of the ethyl acetate (EA) crude extract. The potential isolate was characterized by molecular taxonomy and phylogeny and identified as Streptomyces species and named as Streptomyces sp. VITNK9. The 16S rDNA nucleotide sequence was searched through the GenBank database and showed 83% similarity to Streptomyces vinaceusdrappus. The EA extract prepared from Streptomyces sp. VITNK9 showed moderate antagonistic activity accessed by the formation of zone of growth inhibition against, Aeromonas caviae (15.33 mm), Aeromonas hydrophila (17.66 mm), Edwardsiella tarda (18.33 mm), Vibrio anguillarum (14.33 mm) and Vibrio harveyi (14.33 mm). The MIC value of EA extract was ranged between 0.03-0.125 mg mL-1. The GC-MS spectrum of the ethyl acetate extract revealed the presence of two major compounds, pyrrolo [1,2-A] pyrazine-1,4-Dione (56.67%) and Hexahydro-3-(2-Methylpropyl) (27.91%), respectively. The results of the study suggest that Streptomyces sp. VITNK9 is a potential source for antagonistic secondary metabolites against fish and shellfish bacterial pathogens.

scholarly journals Taxonomic Characterization and Secondary Metabolite Analysis of NEAU-wh3-1: An Embleya Strain with Antitumor and Antibacterial Activity

2020 ◽  
Vol 8 (3) ◽  
pp. 441 ◽  
Author(s):  
Han Wang ◽  
Tianyu Sun ◽  
Wenshuai Song ◽  
Xiaowei Guo ◽  
Peng Cao ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Fermentation Broth ◽  
Sequence Similarity ◽  
Tumor Cell Line ◽  
Triticum Aestivum L ◽  
New Drugs ◽  
Rrna Gene ◽  
Physiological Characterization ◽  
Ic50 Values

Cancer is a serious threat to human health. With the increasing resistance to known drugs, it is still urgent to find new drugs or pro-drugs with anti-tumor effects. Natural products produced by microorganisms have played an important role in the history of drug discovery, particularly in the anticancer and anti-infective areas. The plant rhizosphere ecosystem is a rich resource for the discovery of actinomycetes with potential applications in pharmaceutical science, especially Streptomyces. We screened Streptomyces-like strains from the rhizosphere soil of wheat (Triticum aestivum L.) in Hebei province, China, and thirty-nine strains were obtained. Among them, the extracts of 14 isolates inhibited the growth of colon tumor cell line HCT-116. Strain NEAU-wh-3-1 exhibited better inhibitory activity, and its active ingredients were further studied. Then, 16S rRNA gene sequence similarity studies showed that strain NEAU-wh3-1 with high sequence similarities to Embleya scabrispora DSM 41855T (99.65%), Embleya hyalina MB891-A1T (99.45%), and Streptomyces lasii 5H-CA11T (98.62%). Moreover, multilocus sequence analysis based on the five other house-keeping genes (atpD, gyrB, rpoB, recA, and trpB) and polyphasic taxonomic approach comprising chemotaxonomic, phylogenetic, morphological, and physiological characterization indicated that the isolate should be assigned to the genus Embleya and was different from its closely related strains, therefore, it is proposed that strain NEAU-wh3-1 may be classified as representatives of a novel species of the genus Embleya. Furthermore, active substances in the fermentation broth of strain NEAU-wh-3-1 were isolated by bioassay-guided analysis and identified by nuclear magnetic resonance (NMR) and mass spectrometry (MS) analyses. Consequently, one new Zincophorin analogue together with seven known compounds was detected. The new compound showed highest antitumor activity against three human cell lines with the 50% inhibition (IC50) values of 8.8–11.6 μg/mL and good antibacterial activity against four pathogenic bacteria, the other known compounds also exhibit certain biological activity.

scholarly journals Synthesis andIn VitroEvaluation of New Thiosemicarbazone Derivatives as Potential Antimicrobial Agents

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Zafer Asım Kaplancıklı ◽  
Mehlika Dilek Altıntop ◽  
Belgin Sever ◽  
Zerrin Cantürk ◽  
Ahmet Özdemir
Keyword(s):  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Antimicrobial Agents ◽  
Aromatic Aldehydes ◽  
Antitubercular Activity ◽  
Alamar Blue Assay ◽  
Alamar Blue ◽  
Inhibitory Effects ◽  
Microdilution Method ◽  
Broth Microdilution Method

In an effort to develop potent antimicrobial agents, new thiosemicarbazone derivatives were synthesizedviathe reaction of 4-[4-(trifluoromethyl)phenyl]thiosemicarbazide with aromatic aldehydes. The compounds were evaluated for their inhibitory effects on pathogenic bacteria and yeasts using the CLSI broth microdilution method. Microplate Alamar Blue Assay was also carried out to determine the antimycobacterial activities of the compounds againstMycobacterium tuberculosisH37Rv. Among these derivatives, compounds5and11were more effective againstEnterococcus faecalis(ATCC 29212) than chloramphenicol, whereas compounds1,2, and12and chloramphenicol showed the same level of antibacterial activity againstE. faecalis. Moreover, compound2and chloramphenicol exhibited the same level of antibacterial activity againstStaphylococcus aureus. On the other hand, the most potent anticandidal derivatives were found as compounds2and5. These derivatives and ketoconazole exhibited the same level of antifungal activity againstCandida glabrata. According to the Microplate Alamar Blue Assay, the tested compounds showed weak to moderate antitubercular activity.

scholarly journals The Predatory Myxobacterium Citreicoccus inhibens gen. nov. sp. nov. Showed Antifungal Activity and Bacteriolytic Property against Phytopathogens

2021 ◽  
Vol 9 (10) ◽  
pp. 2137
Author(s):  
Yang Zhou ◽  
Shuoxing Yi ◽  
Yi Zang ◽  
Qing Yao ◽  
Honghui Zhu
Keyword(s):  
Antifungal Activity ◽  
Pathogenic Bacteria ◽  
Phytopathogenic Fungi ◽  
Antagonistic Activity ◽  
Extracellular Proteins ◽  
Morphological Observation ◽  
Rrna Gene ◽  
Fruiting Body Formation ◽  
Predatory Bacteria ◽  
Beneficial Traits

The application and promotion of biological control agents are limited because of poor efficacy and unstable performance in the field. Screening microorganisms with high antagonistic activity, effective adaptability, and high field-survival should be prospected. Myxobacteria are soil predatory bacteria with wide adaptability, which are considered as good antagonists. Here, we report a myxobacterium strain M34 isolated from subtropical forest soil in South China using the Escherichia coli baiting method. Based on the morphological observation, physiological test, biochemical characteristics, 16S rRNA gene sequence, and genomic data, strain M34 was identified as a novel genus and novel species, representing a new clade of Myxococcaceae, for which the name Citreicoccus inhibens gen. nov. sp. nov. is proposed (type strain M34T = GDMCC 1.2275T = KCTC 82453T). The typical features of M34, including fruiting body formation and extracellular fibrillar interconnection, indicated by microscopic observations, contributed to cell adaption in different environments. Furthermore, the strain showed antifungal activity against phytopathogenic fungi and predatory activity to both Gram-negative and Gram-positive phytopathogenic bacteria. The bioprotective mechanisms are attributed to the presence of pyrrolnitrin and derivative with antifungal activity and the extracellular proteins with lytic activity against pathogenic bacteria. Due to its multiple beneficial traits, strain M34 has the potential to be developed into a versatile biocontrol agent for the management of both fungal and bacterial phytopathogens.

scholarly journals Sponge-Associated Actinobacteria: Morphological Character and Antibacterial Activity against Pathogenic Bacteria

2017 ◽  
Vol 3 (1) ◽  
pp. 21-26
Author(s):  
SASMIATI FARACH DITA ◽  
SRI BUDIARTI ◽  
YULIN LESTARI
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Marine Ecosystem ◽  
Morphological Characteristics ◽  
Antibacterial Activities ◽  
Morphological Characters ◽  
Antimicrobial Activities ◽  
Shigella Dysenteriae ◽  
Rrna Gene

Sponge-associated actinobacteria may diverse and have potency to produce bioactive compounds. Diversity and antimicrobial activity of indigenous sponge-associated actinobacteria isolated from the marine ecosystem in Indonesia have not much been explored. This work aimed to assess morphological and antibacterial activity of sponge-associated actinobacteria. The morphological characteristics were examined based on their color of aerial and substrate mycelia, and pigmentation, while antibacterial activities were assayed using the antagonist technique. The selected actinobacterial isolate was identified using 16S rRNA gene. Various sponge-associated actinobacteria were successfully isolated from Hyrtios sp., Callyspongia sp., and Neofibularia sp. sponges. A total of 62 actinobacterial isolates were obtained, and each isolate showed a variety of morphological characters, which could be seen in aerial mass color, substrate mass color, and pigmentation. Actinobacterial isolates were tested against human pathogenic bacteria, i.e. Staphylococcus aureus and Methicillin-Resistant S. aureus, representing Gram-positive, and Escherichia coli EPEC K1-1 and Shigella dysenteriae, representing Gram-negative. Most of actinobacterial isolates had antimicrobial activities at least against one of pathogenic bacteria. High activity was shown by NOHa.2, isolated from Neofibularia, and HRHa.5 isolated from Hyrtios. The NOHa.2 showed the highest antimicrobial activity against S. dysenteriae, meanwhile, HRHa.5 showed antimicrobial activity against 3 of 4 tested bacterial pathogens. These data showed diversity of sponge-asccociated actinobacteria from marine ecosystem in Indonesia, and several of them have potency as source of antibacterial compounds

scholarly journals Evaluation of the probiotic and postbiotic potential of lactic acid bacteria from artisanal dairy products against pathogens

2021 ◽  
Vol 15 (01) ◽  
pp. 102-112
Author(s):  
Nazar Hussain ◽  
Muhammad Tariq ◽  
Per Erik Joakim Saris ◽  
Arsalan Zaidi
Keyword(s):  
Antibacterial Activity ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Pathogenic Bacteria ◽  
16S Rrna Gene Sequencing ◽  
Lactobacillus Delbrueckii ◽  
Human Consumption ◽  
Rrna Gene ◽  
Microdilution Method

Introduction: Probiotic and postbiotic potential of thirty-two strains of lactic acid bacteria (LAB), obtained earlier from artisanal dairy sources in Pakistan, have been investigated against major multi-drug resistant (MDR) and food borne pathogenic bacteria. Methodology: LAB strains were identified by 16S rRNA gene sequencing and their antibacterial activity was assessed by the microdilution method. Four LAB isolates, Weissella confusa PL6, Enterococcus faecium PL7, and Lactobacillus delbrueckii PL11 and PL13 were shortlisted. Their ability to degrade lactose and safety for human consumption in terms of hemolysis and antibiotic susceptibility were assessed in vitro. The antibacterial components in the cell-free supernatants (CFSs) of isolate cultures were characterized biochemically by HPLC. Results: Acid neutralization but not protease treatment abolished the antibacterial activity of CFSs. Lactic, acetic and propionic acids were the main acids in the CFSs, and acid production peaked in the stationary phase of growth. The antibacterial activity of the LAB cultures resulted from secretion of organic acids that lowered the pH. The strains exhibited variable ability to degrade lactose and were non-hemolytic and susceptible to the most common antibiotics. Conclusions: These LAB strains are probiotic candidates for further investigation of their postbiotic role in naturally preserving processed foods and for attenuation of lactose intolerance.

Combination Therapy for Bacterial Pathogens: Naturally Derived Antimicrobial Drugs Augmented with Ulva lactuca Extract

2021 ◽  
Vol 21 ◽  
Author(s):  
Nilushi Indika Bamunuarachchi ◽  
Fazlurrahman Khan ◽  
Young-Mog Kim
Keyword(s):  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Inhibitory Concentration ◽  
Bacterial Pathogens ◽  
Dilution Method ◽  
Gram Positive ◽  
Antimicrobial Drugs ◽  
Gram Negative ◽  
Hexane Extracts ◽  
Conventional Antibiotics

Background: With the growing incidence of microbial pathogenesis, several alternative strategies have been developed. The number of treatments using naturally (e.g., plants, algae, fungi, bacteria, and animals) derived compounds has increased. Importantly, marine-derived products have become a promising and effective approach to combat the antibiotic resistance properties developed by bacterial pathogens. Furthermore, augmenting the sub-inhibitory concentration of the naturally-derived antimicrobial compounds (e.g., hydroxycinnamic acids, terpenes, marine-derived polysaccharides, phenolic compounds) into the naturally derived extracts as a combination therapy to treat the bacterial infection has not been well studied. Objective: The present study was aimed to prepare green algae Ulva lactuca extract and evaluate its antibacterial activity towards Gram-positive and Gram-negative human pathogenic bacteria. Also, revitalize the antibacterial efficiency of the naturally-derived antimicrobial drugs and conventional antibiotics by augmenting their sub-MIC to the U. lactuca extracts. Methods: Extraction was done using a different organic solvent, and its antibacterial activity was tested towards Gram-positive and Gram-negative pathogens. The minimum inhibitory concentration (MIC) of U. lactuca extracts has been determined towards pathogenic bacteria using the micro broth dilution method. The viable cell counting method was used to determine the minimum bactericidal concentration (MBC). The fractional inhibitory concentration (FIC) assay was utilized to examine the combinatorial impact of sub-MIC of two antibacterial drugs using the micro broth dilution method. The chemical components of the extract were analyzed by GC-MS analysis. Results: Among all the extracts, n-hexane extract was found to show effective antibacterial activity towards tested pathogens with the lowest MIC and MBC value. Furthermore, the n-hexane extracts have also been used to enhance the efficacy of the naturally-derived (derived from plants and marine organisms) compounds and conventional antibiotics at their sub-inhibitory concentrations. Most of the tested antibiotics and natural drugs at their sub-MIC were found to exhibit synergistic and additive antibacterial activity towards the tested bacterial pathogens. Conclusions: The augmenting of U. lactuca n-hexane extracts resulted in synergistic and additive bactericidal effects on Gram-positive and Gram-negative human pathogenic bacteria. The present study shows a new alternative strategy to revitalize the antimicrobial activity of naturally derived compounds for treating human bacterial pathogens.

scholarly journals Identification and Antibacterial Characterization of Endophytic Fungi from Artemisia sieberi

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Ibtisam Mohammed Ababutain ◽  
Sahar Khamees Aldosary ◽  
Amal Abdulaziz Aljuraifani ◽  
Azzah Ibrahim Alghamdi ◽  
Amira Hassan Alabdalall ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Ethyl Acetate ◽  
Molecular Identification ◽  
Endophytic Fungi ◽  
Pathogenic Bacteria ◽  
Antibacterial Properties ◽  
Diffusion Method ◽  
Rrna Gene ◽  
Gram Positive ◽  
Artemisia Sieberi

Endophytic fungi serve as a reservoir for important secondary metabolites. The current study focused on the antibacterial properties of endophytic fungi isolated from Artemisia sieberi. Initially, six endophytic fungi were isolated and purified from the stem of A. sieberi. Endophytic fungi were identified by morphological characteristics, as well as by molecular identification using 18S rRNA gene sequencing method. All the six isolates were subjected to the preliminary screening for their antibacterial activity against nine important pathogenic bacteria using the disk-diffusion method. Crude extracts of the most active isolate were obtained using ethyl acetate. Antibacterial activity of the ethyl acetate extract was evaluated using well diffusion method on the selected isolate. The antibacterial efficiency of the selected isolate was evaluated by determining the Minimum Inhibitory Concentration (MIC). MIC values were in appreciable quantity against both Gram-positive and Gram-negative bacteria ranging from 3.125 to 6.25 µg/mL and 12.5 to 50 µg/mL, respectively. This result indicated that Gram-positive bacteria were more susceptible to the endophytic fungi extract. Moreover, the molecular identification results revealed that all the isolates belong to Ascomycota and represented Aspergillus and Penicillium genera and three species: A. oryzae (three isolates), A. niger (one isolate), and P. chrysogenum (two isolates). All six endophytic fungi were able to inhibit the growth of at least two of the tested bacteria. Among the isolated strains, isolate AS2, which identified as P. chrysogenum, exhibited the highest antibacterial activity against all nine tested bacteria and was higher than or equal to the positive control against most of the tested bacteria. Future studies are required to isolate and identify these bioactive substances, which can be considered as a potential source for the synthesis of new antibacterial drugs to treat infectious diseases.

scholarly journals Diversity and Antagonistic Activity of Actinomycete Strains From Myristica Swamp Soils Against Human Pathogens

2014 ◽  
Vol 14 (1) ◽  
pp. 14-19
Author(s):  
Rlnoy Varghese ◽  
S. Jyothy ◽  
A.A. Mohamed Hatha
Keyword(s):  
Western Ghats ◽  
Bacterial Pathogens ◽  
Inhibition Zone ◽  
Antagonistic Activity ◽  
Human Pathogens ◽  
Vibrio Cholera ◽  
Genus Streptomyces ◽  
E Coli ◽  
Gram Positive Bacteria ◽  
Southern Western Ghats

Abstract Under the present investigation Actinomycetes were isolated from the soils of Myristica swamps of southern Western Ghats and the antagonistic activity against different human bacterial pathogens was evaluated. Results of the present study revealed that Actinomycetes population in the soils of Myristica swamp was spatially and seasonally varied. Actinomycetes load was varied from 24×104 to 71×103, from 129×103 to 40×103 and from 31×104 to 84×103 in post monsoon, monsoon and pre monsoon respectively. A total of 23 Actinomycetes strains belonging to six genera were isolated from swamp soils. Identification of the isolates showed that most of the isolates belonged to the genus Streptomyces (11), followed by Nocardia (6), Micromonospora (3), Pseudonocardia (1), Streptosporangium (1), and Nocardiopsis (1). Antagonistic studies revealed that 91.3% of Actinomycete isolates were active against one or more tested pathogens, of that 56.52% exhibited activity against Gram negative and 86.95% showed activity against Gram positive bacteria. 39.13% isolates were active against all the bacterial pathogens selected and its inhibition zone diameter was also high. 69.5% of Actinomycetes were exhibited antibacterial activity against Listeria followed by Bacillus cereus (65.21%), Staphylococcus (60.86%), Vibrio cholera (52.17%), Salmonella (52.17%) and E. coli (39.13%). The results indicate that the Myristica swamp soils of Southern Western Ghats might be a remarkable reserve of Actinomycetes with potential antagonistic activity.

scholarly journals In-vitro antibacterial activity of Rhus javanica against multidrug-resistant uro-pathogens

2019 ◽  
Vol 7 (1) ◽  
pp. 41-46
Author(s):  
Bhavan Saud ◽  
T. Paudel ◽  
T. Sharma ◽  
M. Gyawali ◽  
G. Dhungana ◽  
...  
Keyword(s):  
Urinary Tract Infection ◽  
Antibacterial Activity ◽  
Urinary Tract ◽  
Tract Infection ◽  
Pathogenic Bacteria ◽  
Susceptibility Testing ◽  
Bacterial Pathogens ◽  
Multidrug Resistant ◽  
Health Concern

Background and Objectives: Antibiotic resistance is emerging as a major public health concern. From the ancient time in history, different plants and herbs have been known to have medicinal value. Rhus javanica has been found to show antibacterial activity against pathogenic bacteria. Thus, present study is designed to investigate the prevalence of urinary tract infection causing bacterial pathogens, its antibiogram and effect of Rhus javanica in standard in-vitro condition against multidrug-resistant. Material and Methods: Cross-sectional study was conducted in urinary tract infection suspected patients visiting a clinic in Kalimati, Kathmandu, from July to December 2017. A total of 133 midstream urine samples were collected and cultured in MacConkey agar and Blood agar media and isolates were identified by standard biochemical tests. Antibiotic susceptibility testing was performed according to Clinical and Laboratory Standard Institute (CLSI) guideline. Leaves extract of Rhus javanica was obtained by maceration using 50.0% methanol and susceptibility testing was performed by using cork borer method in Mueller-Hinton agar. Results: Out of total 133 samples, 35.3%showed significant bacterial growth (i.e. 105 cfu/ml) on agar plate. The most predominant organism was Escherichia coli 17.3%, followed by Enterococcus faecalis 6.8%, Klebsiella pneumoniae 3.8%, Pseudomonas aeruginosa 3.0%, Proteus vulgaris 2.3%, and Staphylococcus aureus 2.3%. Out of 47 isolates, 53.2% were Multi Drug Resistant (MDR). Various concentrations of the crude extract used (25, 50, 75 and 100 mg/ml) showed susceptibility to all the bacterial pathogens isolated, with the diameter of zone of inhibition ranging from 12 to 28 mm. Conclusion: Methanolic extract of Rhus javanica showed antibacterial activity against multidrug-resistant isolates of bacterial uropathogens in standard in-vitro condition.

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