Journal: Microorganisms

Article Title: Inhibition of Escherichia coli O157:H7 Growth Through Nutrient Competition by Non-O157 E. coli Isolated from Cattle

doi: 10.3390/microorganisms13122811

Figure Lengend Snippet: Virulence factors identified in twenty-one genetically distinct bovine non-O157:H7 Escherichia coli strains. Virulence factors were identified using Abricate (v1.0.1) to query the virulence factor database (VFDB) and generate virulence profiles for each isolate. Blue cells denote a virulence factor presence while gray cells denote a virulence factor absence. Red cells denote the presence of stx2A and stx2B , genes required for production of Shiga toxin.

Article Snippet: Plates were incubated overnight at 39 °C to produce individual, well-isolated colonies before being UV-inactivated using a UV Stratalinker 2400 (Stratagene, Santa Clara, CA, USA) set to 3000 kJ × 100 for 30 min. A sloppy agar TSB overlay (0.75% w / v granulated agar) with 1.0% ( v / v ) overnight E. coli O157:H7 indicator strain (either ATCC 700728 or ATCC 43888) in TSB was added to the UV-inactivated plate and allowed to set.

Techniques:

Journal: Microorganisms

Article Title: Inhibition of Escherichia coli O157:H7 Growth Through Nutrient Competition by Non-O157 E. coli Isolated from Cattle

doi: 10.3390/microorganisms13122811

Figure Lengend Snippet: Bacteriocin presence and inhibitory activity of non-O157:H7 E. coli strains against O157:H7. ( A ) In vitro inhibition of E. coli O157:H7 by heat-inactivated cell-free supernatants of bovine non-O157:H7 strains under anaerobic conditions. AUC values were determined from OD 630 growth curve data using GrowthCurveR (v0.3.1). Mean AUC values for each of the O157:H7 strains treated with heat-inactivated cell-free supernatant from each of the non-O157:H7 strains were calculated and compared to the mean AUC values for each O157:H7 strain grown in TSB alone to determine the percent difference (%diff) in AUC with dplyr (v1.1.4). Heatmap intensity corresponds to the %diff in the mean area under the curve (AUC) values from growth curves of E. coli O157:H7 indicator strains (ATCC 43888 and ATCC 700728) with and without exposure to heat-inactivated, cell-free supernatants of the bovine non-O157:H7 isolates. Four replicates were conducted for each inhibition assay. Statistical comparisons were made between both bovine non-O157:H7 isolate and each of the two E. coli O157:H7 strains with tukeyHSD within the stats (v3.6.2) package in R. ( B ) Antimicrobial peptides identified in bovine non-O157:H7 and E. coli O157:H7 isolates with Bagel5. Present genes are denoted in blue, and the absence of the gene is denoted in gray.

Article Snippet: Plates were incubated overnight at 39 °C to produce individual, well-isolated colonies before being UV-inactivated using a UV Stratalinker 2400 (Stratagene, Santa Clara, CA, USA) set to 3000 kJ × 100 for 30 min. A sloppy agar TSB overlay (0.75% w / v granulated agar) with 1.0% ( v / v ) overnight E. coli O157:H7 indicator strain (either ATCC 700728 or ATCC 43888) in TSB was added to the UV-inactivated plate and allowed to set.

Techniques: Activity Assay, In Vitro, Inhibition

Journal: Microorganisms

Article Title: Inhibition of Escherichia coli O157:H7 Growth Through Nutrient Competition by Non-O157 E. coli Isolated from Cattle

doi: 10.3390/microorganisms13122811

Figure Lengend Snippet: Nutrient utilization profiles of non-O157:H7 E. coli strains as compared to two O157:H7 strains. ( A ) Percent difference in mean area under the curve (AUC) values for bovine non-O157:H7 strains compared to two E. coli O157:H7 strains (ATCC 43888 and ATCC 700728) in minimal media supplemented with different carbon sources. AUC values were determined from OD 630 growth curve data using GrowthCurveR (v0.3.1). Mean AUC values for non-O157:H7 strains in each nutrient condition were calculated and compared to the mean AUC values for each O157:H7 strain to determine the percent difference (%diff) in AUC with dplyr (v1.1.4). Heatmap intensity corresponds to the %diff in the mean AUC values. Three replicates were conducted for each strain. Statistical comparisons were made between bovine non-O157:H7 strains and each of the two E. coli O157:H7 strains with tukeyHSD within the stats (v3.6.2) package in R. * indicates p < 0.05; ** indicates p < 0.01; *** indicates p < 0.001. ( B ) Percent difference in mean AUC for bovine non-O157:H7 strains compared to ATCC 43888 and ATCC 700728 in minimal media supplemented with ethanolamine as either a carbon or nitrogen source. AUC values were determined from OD 630 growth curve data using GrowthCurveR. Mean AUC values for non-O157:H7 strains in each nutrient condition were calculated and compared to the mean AUC values for each O157:H7 strain to determine the percent difference (%diff) in AUC with dyplr (v1.1.4). Heatmap intensity corresponds to the %diff in the mean AUC values. Three replicates were conducted for each isolate. Statistical comparisons were made between bovine non-O157:H7 strains and each of the two E. coli O157:H7 strains with tukeyHSD using the stats (v3.6.2) package in R. ( C ) KEGG pathway completeness in bovine non-O157:H7 strains and both O157:H7 strains for the catabolism of ethanolamine, galactose, gluconate, glucuronate, mannose, and ribose. Blue denotes a gene as present and the intensity denotes the number of copies of that gene from the Eggnog-mapper (v2.18) annotation of that strain genome. Pathway completeness was determined with ggKegg (v1.1.18).

Article Snippet: Plates were incubated overnight at 39 °C to produce individual, well-isolated colonies before being UV-inactivated using a UV Stratalinker 2400 (Stratagene, Santa Clara, CA, USA) set to 3000 kJ × 100 for 30 min. A sloppy agar TSB overlay (0.75% w / v granulated agar) with 1.0% ( v / v ) overnight E. coli O157:H7 indicator strain (either ATCC 700728 or ATCC 43888) in TSB was added to the UV-inactivated plate and allowed to set.

Techniques:

Journal: Microorganisms

Article Title: Inhibition of Escherichia coli O157:H7 Growth Through Nutrient Competition by Non-O157 E. coli Isolated from Cattle

doi: 10.3390/microorganisms13122811

Figure Lengend Snippet: Bar chart of E. coli O157:H7 ATCC 700728 counts (log 10 CFU/mL) in competition assays with high-competitive (HC) and low-competitive (LC) consortia of non-O157:H7 E. coli strains. E. coli O157:H7 ATCC 700728 counts were assessed after 24 h of co-incubation with HC or LC consortia under aerobic and anaerobic conditions. ATCC 700728 counts were determined on HardyCHROM O157 chromogenic agar plates. Three biological replicates were conducted for each competition assay under each set of conditions. Colony-forming units (CFU)/mL values were calculated, log 10 -transformed, and statistically compared (t.test) in R using the dplyr (v1.1.4) and ggpubr (v0.6.0) packages. * indicates p < 0.05; ** indicates p < 0.01; *** indicates p < 0.001; “ns” indicates p > 0.05.

Article Snippet: Plates were incubated overnight at 39 °C to produce individual, well-isolated colonies before being UV-inactivated using a UV Stratalinker 2400 (Stratagene, Santa Clara, CA, USA) set to 3000 kJ × 100 for 30 min. A sloppy agar TSB overlay (0.75% w / v granulated agar) with 1.0% ( v / v ) overnight E. coli O157:H7 indicator strain (either ATCC 700728 or ATCC 43888) in TSB was added to the UV-inactivated plate and allowed to set.

Techniques: Incubation, Competitive Binding Assay, Transformation Assay