scholarly journals A study on Xenorhabdus and Photorhabdus isolates from Northeastern Thailand: Identification, antibacterial activity, and association with entomopathogenic nematode hosts

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0255943
Author(s):  
Thatcha Yimthin ◽  
Chamaiporn Fukruksa ◽  
Paramaporn Muangpat ◽  
Abdulhakam Dumidae ◽  
Wandee Wattanachaiyingcharoen ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Entomopathogenic Nematode ◽  
Symbiotic Association ◽  
Gram Negative Bacteria ◽  
Antimicrobial Compounds ◽  
Bacterial Strains ◽  
Antibiotic Resistant ◽  
Future Studies ◽  
Mutualistic Association ◽  
Northeastern Thailand

Xenorhabdus and Photorhabdus are gram negative bacteria that can produce several secondary metabolites, including antimicrobial compounds. They have a symbiotic association with entomopathogenic nematodes (EPNs). The aim of this study was to isolate and identify Xenorhabdus and Photorhabdus species and their associated nematode symbionts from Northeastern region of Thailand. We also evaluated the antibacterial activity of these symbiotic bacteria. The recovery rate of EPNs was 7.82% (113/1445). A total of 62 Xenorhabdus and 51 Photorhabdus strains were isolated from the EPNs. Based on recA sequencing and phylogeny, Xenorhabdus isolates were identified as X. stockiae (n = 60), X. indica (n = 1) and X. eapokensis (n = 1). Photorhabdus isolates were identified as P. luminescens subsp. akhurstii (n = 29), P. luminescens subsp. hainanensis (n = 18), P. luminescens subsp. laumondii (n = 2), and P. asymbiotica subsp. australis (n = 2). The EPNs based on 28S rDNA and internal transcribed spacer (ITS) analysis were identified as Steinernema surkhetense (n = 35), S. sangi (n = 1), unidentified Steinernema (n = 1), Heterorhabditis indica (n = 39), H. baujardi (n = 1), and Heterorhabditis sp. SGmg3 (n = 3). Antibacterial activity showed that X. stockiae (bMSK7.5_TH) extract inhibited several antibiotic-resistant bacterial strains. To the best of our knowledge, this is the first report on mutualistic association between P. luminescens subsp. laumondii and Heterorhabditis sp. SGmg3. This study could act as a platform for future studies focusing on the discovery of novel antimicrobial compounds from these bacterial isolates.

scholarly journals Antibacterial Activity of Prismatomeris tetrandra K. Schum Root Extract against Antibiotic Resistance Bacteria

2018 ◽  
Vol 16 (5) ◽  
pp. 341-348
Author(s):  
On-Anong SOMSAP
Keyword(s):  
Antibacterial Activity ◽  
Antibiotic Resistance ◽  
Culture Broth ◽  
Diffusion Method ◽  
Resistant Bacteria ◽  
Root Extract ◽  
Gram Negative Bacteria ◽  
Antibiotic Resistant ◽  
Gram Positive Bacteria ◽  
Colony Forming Units

Antibiotic resistance bacteria has become an increasing problem now today due to many factors. This study investigates the efficacy of Prismatomeris tetrandra K. Schum root extract as a new source of antibacterial activity for antibiotic resistant bacteria using agar well diffusion method. The results showed that S. aureus TISTR517 exhibited more sensitivity to P. tetrandra K. Schum root extract than other Gram-positive bacteria indicator strains. On the other hand, Gram-negative bacteria exhibited resistance to P. tetrandra K. Schum root extract. The study further showed the activity between P. tetrandra K. Schum root extract and gentamycin (10 µg), it revealed that MRSA142 was resistant to gentamycin (10µg) but sensitive to P. tetrandra K. Schum root extract. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) was evaluated by using S. aureus TISTR517 and MRSA142 as indicator strains. The MIC value was 0.59 mg/mL and 1.17 mg/mL for S. aureus TISTR517 and MRSA142, respectively. MBC assay demonstrated that the MBC value was 9.75 mg/mL and 150 mg/mL for S. aureus TISTR517 and MRSA142 respectively. The mode of action was investigated with the presence of P. tetrandra K. Schum root extract in the culture broth. The action of P. tetrandra K. Schum root extract was revealed of bacteriostatic activity due to the Optical density (OD) at 600 nm and Colony-Forming Units (CFU) of indicator strains were continuously decreased.

Novel bacteria associated with Arctic seashore lichens have potential roles in nutrient scavenging

2014 ◽  
Vol 60 (5) ◽  
pp. 307-317 ◽  
Author(s):  
Margrét Auður Sigurbjörnsdóttir ◽  
Starri Heiðmarsson ◽  
Anna Rut Jónsdóttir ◽  
Oddur Vilhelmsson
Keyword(s):  
Denaturing Gradient Gel Electrophoresis ◽  
Symbiotic Association ◽  
Bacterial Strains ◽  
Rdna Sequencing ◽  
Gradient Gel Electrophoresis ◽  
Species Specific ◽  
Mutualistic Association ◽  
Modest Level

While generally described as a bipartite mutualistic association between fungi and algae or cyanobacteria, lichens also host diverse and heretofore little explored communities of nonphototrophic endolichenic bacteria. The composition and possible roles of these bacterial communities in the lichen symbiotic association constitute an emerging field of research. Saxicolous (rock-dwelling) seashore lichens present an unusual environment, characterized by rapid fluctuations in temperature, salinity, exposure to solar radiation, etc. The present study focuses on the bacterial biota associated with 4 species of crustose, halophilic, saxicolous seashore lichens found in northern Iceland. A denaturing gradient gel electrophoresis based characterization of the composition of the lichen-associated microbiotas indicated that they are markedly lichen-species-specific and clearly distinguishable from the environmental microbiota represented by control sampling. A collection of bacterial strains was investigated and partially identified by 16S rDNA sequencing. The strains were found to belong to 7 classes: Alphaproteobacteria, Bacilli, Actinobacteria, Flavobacteria, Cytophagia, Sphingobacteria, and Gammaproteobacteria. Several isolates display only a modest level of similarity to their nearest relatives found in GenBank, suggesting that they comprise previously undescribed taxa. Selected strains were tested for inorganic phosphate solubilization and biodegradation of several biopolymers, such as barley β-glucan, xylan, chitosan, and lignin. The results support a nutrient-scavenging role of the associate microbiota in the seashore lichen symbiotic association.

scholarly journals Some endemic medicinal plants of Andamans with antimicrobial potential

2016 ◽  
Vol 1 (1) ◽  
pp. 10
Author(s):  
Asma Bibi ◽  
A. Thangamani ◽  
V. Venkatesalu
Keyword(s):  
Antibacterial Activity ◽  
Antifungal Activity ◽  
Pathogenic Bacteria ◽  
Phytopathogenic Fungi ◽  
Gram Negative Bacteria ◽  
Andaman Islands ◽  
Bacterial Strains ◽  
Endemic Plant ◽  
Ethanol Extracts ◽  
Endemic Plant Species

The present study was aimed to determine the antimicrobial activity of some endemic plant species used in folkloric medicine by the inhabitants of Andaman Islands, India. The ethanol extracts prepared from the leaves of four plants viz; Alstonia kurzii, Tabernaemontana crispa, Mangifera andamanica and Vitex diversifolia were assessed for antibacterial activity against clinically isolated human pathogenic bacteria and antifungal activity against some phytopathogenic fungi. The ethanol extracts showed more inhibition towards Gram positive than Gram negative bacteria and the bacterial strains showed more susceptibility than the fungal strains tested. Among the plants, Vitex diversifolia exhibited the highest antibacterial activity and Mangifera andamanica showed the highest antifungal activity.

scholarly journals Evaluation of antibacterial activity of vitamin C against human bacterial pathogens

2023 ◽  
Vol 83 ◽  
Author(s):  
S. Mumtaz ◽  
S. Mumtaz ◽  
S. Ali ◽  
H. M. Tahir ◽  
S. A. R. Kazmi ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Vitamin C ◽  
Bacterial Infections ◽  
Unmet Need ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative ◽  
Adjunct Treatment

Abstract Now a day’s multidrug resistance phenomenon has become the main cause for concern and there has been an inadequate achievement in the development of novel antibiotics to treat the bacterial infections. Therefore, there is an unmet need to search for novel adjuvant. Vitamin C is one such promising adjuvant. The present study was aimed to elucidate the antibacterial effect of vitamin C at various temperatures (4°C, 37°C and 50°C) and pH (3, 8, and 11), against Gram-positive and Gram-negative bacteria at various concentrations (5-20 mg/ml) through agar well diffusion method. Growth inhibition of all bacterial strains by vitamin C was concentration-dependent. Vitamin C significantly inhibited the growth of Gram-positive bacteria: Bacillus licheniformis (25.3 ± 0.9 mm), Staphylococcus aureus (22.0 ± 0.6 mm), Bacillus subtilis (19.3 ± 0.3 mm) and Gram-negative bacteria: Proteus mirabilis (27.67 ± 0.882 mm), Klebsiella pneumoniae (21.33±0.9 mm), Pseudomonas aeruginosa (18.0 ± 1.5 mm) and Escherichia coli (18.3 ± 0.3 mm). The stability of vitamin C was observed at various pH values and various temperatures. Vitamin C showed significant antibacterial activity at acidic pH against all bacterial strains. Vitamin C remained the stable at different temperatures. It was concluded that vitamin C is an effective and safe antibacterial agent that can be used in the future as an adjunct treatment option to combat infections in humans.

scholarly journals Lysophosphatidylcholine Potentiates Antibacterial Activity of Polymyxin B

2020 ◽  
Vol 64 (12) ◽  
Author(s):  
Jitender Yadav ◽  
Sana Ismaeel ◽  
Ayub Qadri
Keyword(s):  
Antibacterial Activity ◽  
Polymyxin B ◽  
Resistant Bacteria ◽  
Bacterial Membrane ◽  
Gram Negative Bacteria ◽  
Drug Resistant ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Drug Resistant Bacteria

ABSTRACT Polymyxin B, used to treat infections caused by antibiotic-resistant Gram-negative bacteria, produces nephrotoxicity at its current dosage. We show that a combination of nonbactericidal concentration of this drug and lysophosphatidylcholine (LPC) potently inhibits growth of Salmonella and at least two other Gram-negative bacteria in vitro. This combination makes bacterial membrane porous and causes degradation of DnaK, the regulator of protein folding. Polymyxin B-LPC combination may be an effective and safer regimen against drug-resistant bacteria.

scholarly journals Synthesis of Some Quinoxaline Sulfonamides as a Potential Antibacterial Agent

2021 ◽  
pp. 116-132
Author(s):  
Festus O. Taiwo ◽  
Craig A. Obafemi ◽  
David A. Akinpelu A. Akinpelu
Keyword(s):  
Antibacterial Activity ◽  
Broad Spectrum ◽  
Antibacterial Agent ◽  
Antibacterial Property ◽  
Antibacterial Properties ◽  
Antimicrobial Properties ◽  
Pharmacological Properties ◽  
Antimicrobial Compounds ◽  
Bacterial Strains ◽  
Bactericidal Effects

Aims: This studies aims at the synthesis of new heterocyclic systems and study its biological and pharmacological properties. Objective: This study was designed to synthesized some quinoxaline-2,3-dione with sulfonamide moiety, characterize the synthesized compounds, and study the antimicrobial properties of the synthesized compounds on some bacterial strains. Materials and Methods: Six quinoxaline-6-sulfonohydrazone derivatives were synthesized by reacting quinoxaline-6-sulfonohydrazine with some substituted benzaldehydes and ketones. The compounds were tested for their potential antibacterial properties. Results: All the test compounds possessed promising antibacterial property against a panel of bacterial strains used for this study. The MIC values exhibited by these compounds ranged between 0.0313 and 0.250 mg/mL. Among the compounds tested, compound 2 showed appreciable antibacterial activity. Discussion and Conclusion: The study concluded that all the compounds exhibited appreciable bactericidal effects towards all the bacterial strains, particularly, compound 2 This is an indication that such compounds possessing broad spectrum activities will be useful in formulating antimicrobial compounds which could be used to treat infections caused by pathogens that are now developing resistance against the available antibiotics.

scholarly journals Antibacterial and Antibiofilm Activity and Mode of Action of Magainin 2 against Drug-Resistant Acinetobacter baumannii

2018 ◽  
Vol 19 (10) ◽  
pp. 3041 ◽  
Author(s):  
Min Kim ◽  
Na Kang ◽  
Su Ko ◽  
Jonggwan Park ◽  
Eunji Park ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Acinetobacter Baumannii ◽  
Bacterial Infections ◽  
High Stability ◽  
Therapeutic Agents ◽  
Antibiofilm Activity ◽  
Gram Negative Bacteria ◽  
Drug Resistant ◽  
Biofilm Inhibition ◽  
Antibiotic Resistant

Antimicrobial peptides (AMPs) are promising therapeutic agents for treating antibiotic-resistant bacterial infections. Previous studies showed that magainin 2 (isolated from African clawed fogs Xenopus laevis) has antimicrobial activity against gram-positive and gram-negative bacteria. The present study was conducted to investigate the antibacterial activity of magainin 2 against Acinetobacter baumannii. Magainin 2 showed excellent antibacterial activity against A. baumannii strains and high stability at physiological salt concentrations. This peptide was not cytotoxic towards HaCaT cells and showed no hemolytic activity. Biofilm inhibition and elimination were significantly induced in all A. baumannii strains exposed to magainin 2. We confirmed the mechanism of magainin 2 on the bacterial outer and inner membranes. Collectively, these results suggest that magainin 2 is an effective antimicrobial and antibiofilm agent against A. baumannii strains.

Al2O3 Nanopowders, a Suitable Compound for Active Control of Biofouling

2015 ◽  
Vol 32 ◽  
pp. 71-80
Author(s):  
Mohsen Mehregan ◽  
Hossein Soltaninejad ◽  
Behnaz Toluei Nia ◽  
Hadi Zare-Zardini ◽  
Masoud Zare-Shehneh ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Antibacterial Activity ◽  
Blood Cells ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
X Ray Diffraction ◽  
Gram Positive ◽  
Gram Negative ◽  
X Ray

The formation of biofilm (Biofouling) in different surface is the great concern in types of fields, especially in medical and health system as well as in membrane technology. The present study deals with the synthesis and characterization of Al2O3 nanopowders with antibacterial activity which can be a potentially utilized material for biocompatible implants. Nanostructure was synthesized based on sol-gel method and then, crystallite size, and microstructural and morphological characterization of nanostructure were determined by X-ray diffraction, electron-microscopic techniques - scanning electron microscopy (SEM) and transmission electron microscopy (TEM). According to X-ray diffraction, the value of particle size for Al2O3 nanopowders is 20.85 nm. In the following, the antibacterial activity of Al2O3 nanoparticles was assessed on three gram positive and three gram negative bacteria by radial diffusion assay and measurement of minimum inhibitory concentration (MIC). The toxicity of Al2O3 nanopowders on blood cells was also assessed. The results showed that this nanostructure has potent antibacterial activity against gram positive and gram negative bacteria. The synthesized Al2O3 nanopowders showed the antimicrobial activity against antibiotic resistant bacterium, Staphylococcus aureus. Significant antibacterial activity of this nanostructure was seen to have a greatest effect on Bacillus cereus with the MIC value of 9.2 μg/ml; while, among bacterial strains, Salmonellatyphimurium was investigated to be the most resistant one with the MIC of 35.6 μg/ml. Al2O3 nanopowders showed no toxicity on blood cells. according to acquired data in this study, Al2O3 nanopowders may be a good material for inhibition of biofilm formation.

scholarly journals Antibacterial activity of cobalt(II) complexes with some benzimidazole derivatives

2008 ◽  
Vol 73 (12) ◽  
pp. 1153-1160 ◽  
Author(s):  
S.O. Podunavac-Kuzmanovic ◽  
V.M. Leovac ◽  
D.D. Cvetkovic
Keyword(s):  
Antibacterial Activity ◽  
Chemical Structure ◽  
Antibacterial Activities ◽  
Benzimidazole Derivatives ◽  
Wall Structure ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative

The antibacterial activities of cobalt(II) complexes with two series of benzimidazoles were evaluated in vitro against three Gram-positive bacterial strains (Bacillus cereus, Staphylococcus aureus, and Sarcina lutea) and one Gram-negative isolate (Pseudomonas aeruginosa). The minimum inhibitory concentration was determined for all the complexes. The majority of the investtigated complexes displayed in vitro inhibitory activity against very persistent bacteria. They were found to be more active against Gram-positive than Gram-negative bacteria. It may be concluded that the antibacterial activity of the compounds is related to the cell wall structure of the tested bacteria. Comparing the inhibitory activities of the tested complexes, it was found that the 1-substituted- -2-aminobenzimidazole derivatives were more active than complexes of 1-substituted- 2-amino-5,6-dimethylbenzimidazoles. The effect of chemical structure on the antibacterial activity is discussed.

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