Exiguobacterium sp. is endowed with antibiotic properties against Gram positive and negative bacteria

Abstract

Objective In order to isolate and identify bacteria that produce potentially novel bactericidal/bacteriostatic compounds, two ponds on the campus of the Rochester Institute of Technology (RIT) were targeted as part of a bioprospecting effort. Results One of the unique isolates, RIT 452 was identified as Exiguobacterium sp. and subjected to whole-genome sequencing. The genome was assembled and in silico analysis was performed to predict the secondary metabolite gene clusters, which suggested the potential of Exiguobacterium RIT452 for producing antibiotic compounds. Extracts of spent growth media of RIT452 were active in disc diffusion assays performed against four reference strains, two Gram-negative (E. coli ATCC 25922 and P. aeruginosa ATCC 27853) and two Gram-positive (B. subtilis BGSC 168 and S. aureus ATCC 25923). Differential extraction and liquid chromatography was used to fractionate the extracts. Efforts to identify and elucidate the structure of the active compound(s) are still ongoing.

Comparative Analysis of Microbial Community Diversity and Dynamics on Diseased Tubers During Potato Storage in Different Regions of Qinghai China

“…In addition, bacteria of the genera Flavobacteriaceae and Carnobacteriaceae , which also existed in diseased potatoes, have been reported to be the main components leading to meat deterioration during meat storage( Zhao et al, 2015 ). In the analysis of indicator species, Fusarium , Alternaria and Colletotrichum , which are the important pathogenic fungi of potatoes, were mostly enriched in Group “C,” while the potentially antagonistic fungi Mucor and Penicillium ( Mardani and Hadiwiyono 2018 ; Teixeira et al, 2012 ) were also present in Group “C,” but antagonistic bacteria, such as Bacillus , Pantoea , and Exiguobacterium ( Abo-Elyousr and Hassan, 2021 ; Cavanaugh et al, 2021 ; Fernandes et al, 2021 ), were distributed to varying degrees in Group “A” and Group “C.” Further functional predictive analysis confirmed that Pathotroph-Saprotroph-Symbiotroph, Pathotroph-Symbiotroph and Saprotroph were the main nutritional types of fungi in diseased potato tubers. In addition, the Pathotroph-Saprotroph-Symbiotroph type in Group “C” (average abundance was 41%) was significantly higher than that in Group “A” (average abundance was 29%), while Pathotroph-Symbiotroph in Group “A” (average abundance was 56%) was higher than that in Group “C” (average abundance was 14%), furthermore, the types of Pathotroph and Saprotroph were also higher in Group “C”.…”

A novel method of testing the antimicrobial potentials ofExiguobacterium aurantiacum, Lysinibacillus boronitoleransandBacillus megaterium

“…The methodology developed is simple and functional, as zones of inhibition larger than the negative control were produced by most bacterial extracts against the two test pathogens. The new method was tested using microorganisms such as Exiguobacterium aurantiacum, Lysinibacillus boronitolerans, Bacillus megaterium , that are known to have antimicrobial properties against gram positive and gram negative bacteria (2, 7, 9). However prior studies used technically challenging methods to extract antimicrobial substances from these bacteria.…”

“…Current methods to screen the antimicrobial potential of bacteria can be expensive and time-consuming. Common practices include the use of centrifugation, compound fractionation, materials such as Nutrient Broth, Lysogeny Broth and more (2, 10). Whilst these methodologies often provide accurate and precise results, they are also hard to replicate and scale as the apparatus required is costly.…”

“… Abstract Microorganisms can be an effective source for antimicrobial compounds including peptides that provide an evolutionary advantage to them in specific niches. Prior studies have noted the antimicrobial properties of Exiguobacterium aurantiacum, Lysinibacillus boronitolerans and Bacillus megaterium but they used time- and resource-intensive procedures to prepare the extracts (2, 10). We wanted to explore a more cost-effective, time-effective and simpler method of testing the antimicrobial potential of bacterial extracts.…”

Draft Genome Sequences of Three Antibiotic-Producing Soil Bacteria, Staphylococcus pasteuri WAM01, Peribacillus butanolivorans WAM04, and Micrococcus yunnanensis WAM06, with Growth-Inhibiting Effects against CommensalNeisseriaStrains

“…Bioprospecting for antibiotics produced by microbes in soil communities could uncover novel inhibitory compounds against the gonococcus and other important human pathogens ( 7 , 8 ). This approach can be implemented in undergraduate classrooms as an inquiry-based exercise, which was previously demonstrated by the Small World Initiative ( 9 , 10 ), Tiny Earth ( 11 , 12 ), and academic groups ( 13 – 16 ). Developed protocols screen for soil bacteria that produce antibiotics effective against “safe” bacteria (biosafety level 1 [BSL1]), which may also have inhibitory properties against pathogens within the same genus (e.g., ESKAPE pathogens [ 17 , 18 ]).…”