37-1 |
Phage therapy: From a historic perspective to the potential eradication of E. coli O157 in livestock |
E. KUTTER1, R. Raya1, P. Varey1, M. Dyen1, A. Brabban1, T. S. Edrington2, and T. R. Callaway2. (1) Lab. 1, Evergreen State College, 2700 Evergreen Pkwy. N.W., Olympia, WA 98505, (2) Food & Feed Safety Research Unit, USDA-ARS-Southern Plains Agricultural Research Center, 2881 F&B Rd., College Station, TX 77845-0000 It is becoming increasingly clear that bacteriophages are a major mechanism for the control of microbial balance throughout the biosphere. For example, ¼ of the bacteria in the oceans are infected with phages at any given time; this plays a major role in regulating available nutrient supplies. Already in his initial 1917 paper, phage discoverer Felix d’Herelle reported that phages against the bacillus of Shiga are particularly easily isolated from the stools of patients recovering from dysentery; such findings are routine. While much emphasis has been placed on the use of phages for human disease, significant work has also focused on the protection and safety of the food chain. By 1919, d’Herelle was applying phage in the control of avian typhosis, and the later work of Smith and Huggins on treating diarrheal diseases in cattle and other livestock remains the clearest Western research on phage therapy. Interest in agricultural applications is now rapidly expanding worldwide. Here, we will summarize the advances and challenges in phage work related to problems like mastitis in cattle and other livestock diseases, to dealing with Vibrio vulnificus contamination in oysters, to treatment of Aeromonas salmonicida in fish, and to plant diseases such as Erwinia infections of fruit trees (causing fire blight) and root crops (causing soft rot). It is clear we need to study phage infection under conditions reflecting the natural environment. For example, the first published report on phages against E. coli O157 acknowledged that their phages worked well under conditions of heavy aeration but not anaerobically, and that they thus might be useful for bean sprouts but not cattle. We will describe phage we isolated from a herd of sheep naturally resistant to O157 and the subsequent reintroduction of these and other phages isolated from sheep and pigs into livestock for treatment purposes, and also show very significant and relevant differences in infection patterns of T-even phages between conditions of anaerobic respiration, anaerobic fermentation, and the standard aerobic laboratory conditions.
Session 37, Phage therapy as it applies to food public health bacteriology
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