Preliminary communication
https://doi.org/10.17113/ftb.53.02.15.3731
Antagonistic Effect of Pseudomonas sp. CMI-1 on Foodborne Pathogenic Listeria monocytogenes
Ágnes Belák
; Department of Microbiology and Biotechnology, Faculty of Food Science, Corvinus University of Budapest, Budapest, Hungary
Anna Maráz
; Department of Microbiology and Biotechnology, Faculty of Food Science, Corvinus University of Budapest, Budapest, Hungary
Abstract
Bacterial isolates derived from food or raw food materials of animal origin were screened for potential antagonistic activity against foodborne pathogenic Listeria monocytogenes. Using the agar spot method, ten out of the 94 tested bacteria showed antilisterial activity. All of the antagonistic isolates identified by sequence analysis as strains of the genus Pseudomonas were able to inhibit the growth of all the examined Listeria species including the ruminal pathogenic L. ivanovii and the opportunistic human pathogenic L. innocua. Pseudomonas sp. CMI-1 had the highest inhibitory eff ect on the growth of different Listeria strains. Co-culturing studies revealed that the inhibition of L. monocytogenes could not be achieved effi ciently. Although the population of the Pseudomonas sp. CMI-1 strain increased by up to 10 orders of magnitude during 2 days of culturing period at 20 °C in the presence of L. monocytogenes, the cell count of the pathogen also increased by approx. 6 orders of magnitude. At the same time, appropriate inhibition of cell-free supernatants generated from 6-day-old cultures of Pseudomonas sp. CMI-1 was observed. The inhibitory compound of this antagonistic strain is presumably a chromopeptide siderophore, whose activity and production can be aff ected by iron supplementation, and which had an absorption maximum typical of siderophores of fl uorescent Pseudomonas species. Production of the antilisterial substance was influenced by the oxygen concentration, as in static cultures the concentration of the siderophore was higher than in shake flask cultures.
Keywords
antagonistic bacteria; Listeria monocytogenes; siderophore; fluorescent Pseudomonas sp
Hrčak ID:
140238
URI
Publication date:
23.6.2015.
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