Alterations of the phylloepiphytic bacterial community associated with interactions of Escherichia coli O157:H7 during storage of packaged spinach at refrigeration temperatures

Phyllopshere Bacterial Community Structure of Spinach (Spinacia oleracea) as Affected by Cultivar and Environmental Conditions at Time of Harvest

“…In this study the majority of the members of the epiphytic community belonged to the phylogenetic group α-Proteobacteria and Bacteroidetes. The same phylogenetic groups are dominant on spinach and other plant leaf surfaces including Zea mays and Capsicum annuum [4,34]. The dominant phylogenetic group on spinach and other leaf surfaces is the γ-Proteobacteria [3,34].…”

Factors affecting cell population density during enrichment and subsequent molecular detection of Salmonella enterica and Escherichia coli O157:H7 on lettuce contaminated during field production

“…In vitro studies have demonstrated that co-culture of human pathogens like E. coli O157:H7 and Salmonella can be out-competed by coliforms and several other Enterobacteria that are part of the phyllopshere (Bennett et al, 1998;Cooley, Chao, & Mandrell, 2006;Cooley, Miller, & Mandrell, 2003;Franco et al, 2010;Lopez-Velasco, Tyddings, et al, 2012), and thus interfere with accurate detection and increasing the chance of obtaining either a false positive or negative outcome. Several efforts using high throughput technologies have demonstrated the enormous diversity on the plant phyllosphere (Delmotte et al, 2009;Lopez-Velasco, Davis, Boyer, Williams, & Ponder, 2010;Rastogi et al, 2012) and therefore the interplay of these complex communities during enrichment with pathogenic bacteria during culture enrichment should be considered.…”

Effect of Two Different Commercial DNA Extraction Kits on the Bacterial 16S Ribosomal RNA Gene Denaturing Gradient Gel Electrophoresis Profile of Arabian Gelding Feces

“…Each PCR reaction contained 25µL HotStart-IT® PCR Master Mix 2x (USB 71156, Cleveland, OH), 0.5mM of each primer, and 100ng DNA in a 50µL total volume. The PCR protocol consisted of denaturation at 94°C for 10 min followed by 19 cycles of 94°C for 1 min, annealing at 64°C for 1 min with the temperature decreasing 1°C every other cycle, and elongation at 72°C for 3 minutes followed by 9 cycles of denaturation at 94°C for 1 minute, annealing at 55°C for 1 minute, and elongation at 72°C for 3 [30,32]. The relative quantity of PCR products was assessed on a 1.5% agarose gel (FisherScientific, Atlanta, GA), stained with 0.2% ethidium bromide (Fisher BP102), and visualized under UV light.…”

“…All DGGE analyses were performed using the DCode™ Universal Detection System (Bio-Rad, Hercules, CA). Forty-three microliters of the 16S rRNA PCR amplicons from each amplified DNA sample was applied to an 8% polyacrylamide gel with a 35-60% urea and formamide denaturant gradient as previously described [32]. Electrophoresis was performed at 60°C in 1 X TAE buffer (Fisher-Scientific) at 85V for 16.5 hours.…”

“…Dendrograms were constructed based on similarity of banding patterns between samples using the unweighted pair group method with mathematical averages (UPGMA; Dice coefficient of similarity) [32].…”