The increasing prevalence of multidrug-resistant (MDR) pathogens necessitates the discovery of novel antibacterial agents. In this study, culturable soil bacteria from the Dead Sea region (Jordan) were isolated and the antibacterial activity of their extracellular metabolites were evaluated. Twenty-one isolates were screened using a perpendicular-streak primary assay; three stable producers (GH-15, GH-20, GH-21) were prioritized. Cell-free supernatants were extracted with n-hexane and ethyl acetate, tested using agar well diffusion, and profiled using thin-layer chromatography (TLC) coupled with bioautography (GH-15). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by broth microdilution against Bacillus subtilis ATCC 11774, B. cereus ATCC 10876, Staphylococcus aureus ATCC 29213, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, and Proteus mirabilis ATCC 29906. The ethyl acetate extract of GH-15 showed the lowest MIC against E. coli (0.073 mg/mL). The MIC values were equal to MBC for several strains, indicating bactericidal activity. For GH-15 hexane extract, the lowest MIC was 2.625 mg/mL (E. coli and B. cereus), and the lowest MBC was 5.25 mg/mL (E. coli and B. cereus). Dead Sea soils yielded bacterial isolates with broad antibacterial activity; solvent-dependent activity and TLC-bioautography suggested multiple bioactive metabolites, supporting further purification and chemical identification.
Silver nanoparticles synthesized by different species
Introduction and Aim: Klebsiella pneumoniae is a Gram-negative bacterium responsible for a wide range of infections, including respiratory tract infections (RTIs). This research was aimed to study the antibacterial and antibiofilm effect of AgNPs produced by Gram positive and negative bacteria on RTIs associated with K. pneumoniae. Materials and Methods: The biofilm formation of K. pneumoniae was determined by tube method qualitatively from select bacterial species characterized by UV-Visible spectroscopy. The antibacterial susceptibility of the bacteria AgNPs was tested for their antibacterial and antibiofilm activity on a clinical isolate of K. pneumoniae. Results: K. pneumoniae isolated from RTIs were strong biofilm producers. The ant
... Show MoreIntroduction and Aim: Klebsiella pneumoniae is a Gram-negative bacterium responsible for a wide range of infections, including respiratory tract infections (RTIs). This research was aimed to study the antibacterial and anti-biofilm effect of AgNPs produced by Gram positive and negative bacteria on RTIs associated with K. pneumoniae. Materials and Methods: The biofilm formation of K. pneumoniae was determined by tube method qualitatively from select bacterial species characterized by UV-Visible spectroscopy. The antibacterial susceptibility of the bacteria AgNPs was tested for their antibacterial and antibiofilm activity on a clinical isolate of K. pneumoniae. Results: K. pneumoniae isolated from RTIs were strong biofilm prod
... Show MoreFive species of Lactic acid bacteriawere isolated from raw milk, yoghurt, vegetables and pickles, Lactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus brevis, Lactobacillus casei and Lactobacillus bulgaricus isolates were identified by 16S rRNA gene. Evaluate of antimicrobial activity against all the bacterial strains Staphylococcus aureus, Salmonella spp., Pseudomonas fluorescens, Escherichia coli, Bacillus cereus and Bacillus subtilis. It showed that bacteriocin of Lactic acid bacteriamore effective than supernatant of lactic acid bacteria, the results showed that isolatemost efficient isolate belonging to Lactobacillus brevis, the diameter of the inhibition of the bacteriocin of Lactobacillus brevis were 27.7, 26.3 and 25.1
... Show MoreSome microorganisms can produce nanocellulose, which is known as bacterial nanocellulose (BNC); the most active bacterial producer is acetic acid bacteria (AAB), which is a gram-negative, motile and obligate aerobic belongs to the family Acetobacteraceae. Bacterial nanocellulose has excellent attention in medical (surgical domain), industrial and pharmaceutical fields because of its flexible properties, characteristics and advantages. So, in this study, the AAB (5AC) isolate was isolated from apple vinegar. The production of BNC was performed by using a natural medium called palm dates liquid medium, the produced bacterial Cellulose was purified by using the sodium hydroxide method; it was observed that the wet weight of the BNC was a
... Show MoreMastitis is an udder tissue inflammation which has infected various species of animals. It happens through several types of pathogenic bacteria, particularly Streptococcus agalactiae. GBS is a leading cause of cow mastitis. In our sample, 9.52% of Streptococcus agalactiae were isolated which were collected from bovine mastic milk and identified by biochemical tests such as catalase, oxidase, Production of indole, fermentation of sugar, an examination of antibiotic sensitivity, CAMP test and group kits of Lancefield. The results showed that all Streptococcus agalactiae isolate was diagnosed by CAMP test by the appearance of the arrowhead in blood agar and by the appearance of visible agglutination on a card in the serological grouping kit of
... Show MoreThis study was aimed to investigate the load of bacterial contaminant in fresh meat with different types of bacteria.One handered and seven samples were collected from different regions of Baghdad . These samples included 37 of fresh beef 70 of fresh sheep meat. All samples were cultured on different selective media to identitfy of contaminated bacteria .The result revealed that The percentage of bacterial isolate from raw sheep meat were, % 23.8of StreptococcusgroupD,29.4 % of Staphylococcus aureus ,14.7 % of E.coli , %4.9of Salmonella spp, ,%3.5 of pseudomonas aeruginosa, %14.7.%14.7 of Proteus spp.% 2.1 of Listeria spp while the raw beef meat content %5.55 of Staphylococcus aureus, %8.14 of streptococcus group D , %5.18 %1.85 of E.coli,
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