Characterization of interactions between Escherichia coli O157:H7 with epiphytic bacteria in vitro and on spinach leaf surfaces

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• 作者：Gabriela Lopez-Velasco^a ; ¹ ; Heather A. Tydings^a ; ¹ ; Renee R. Boyer^a ; Joseph O. Falkinham III^b ; Monica A. Ponder^a ; ^{mponder@vt.edu}
• 关键词：Phylloepiphytes ; Phyllosphere bacteria ; Bacterial interactions ; Escherichia coli O157 ; H7 ; Antagonism
• 刊名：International Journal of Food Microbiology
• 出版年：2012
• 出版时间：15 February 2012
• 年：2012
• 卷：153
• 期：3
• 页码：351-357
• 全文大小：221 K

文摘

This study characterized the types of interactions between Escherichia coli O157:H7 and spinach phylloepiphytic bacteria and identified those that influence persistence of E. coli O157:H7 on edible plants. A total of 1512 phylloepiphytic bacterial isolates were screened for their ability to inhibit or to enhance the growth of E. coli O157:H7 in vitro and on spinach leaf surfaces. Fifteen different genera, the majority belonging to Firmicutes and Enterobacteriaceae, reduced growth rates of E. coli O157:H7 in vitro by either nutrient competition or acid production. Reduced numbers of E. coli O157:H7 were recovered from detached spinach leaves that were co-inoculated with epiphytic isolates belonging to five genera. A 1.8 log reduction in E. coli O157:H7 was achieved when co-inoculated with Erwinina perscinia and 20 % cellobiose, a carbon source used by the phylloepiphytes but not E. coli O157:H7. The reduction on leaves was significantly less than reduction measured in vitro. Phylloepiphytic bacteria belonging to eight different genera, increased numbers of E. coli O157:H7 when co-cultured in vitro on spent medium and when co-cultured on detached spinach leaves. The results, showing reduction of E. coli O157:H7 numbers by natural epiphytic bacteria, support the hypothesis that native plant microbiota can be used for bio-control of foodborne pathogens, however, other epiphytes may promote the persistence of enteric pathogens on the phyllosphere.