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ARS Home » Northeast Area » Ithaca, New York » Robert W. Holley Center for Agriculture & Health » Research » Publications at this Location » Publication #98114

Title: THE PERSISTENCE OF ACID-RESISTANT ESCHERICHIA COLI IN STORED CATTLE FECES

Author
item ADAMOVICH, DAVID - CORNELL UNIVERSITY
item DIEZ-GONZALEZ, FRANCISCO - CORNELL UNIVERSITY
item Russell, James

Submitted to: American Society for Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Recent work (Diez-Gonzalez et al. Science 281: 166-1168, 1998) indicated that cattle consuming large amounts of grain (90%) had 1000-fold more E. coli than cattle fed hay, and grain fermentation in the colon increased volatile fatty acids, decreased pH and increased acid-resistance of E. coli. Acid shock experiments (pH 2.0) indicated that cattle fed grain had 1 million-fold more acid-resistant E. coli than cattle fed hay, but the persistence of acid-resistant E. coli in manure was not examined. In our experiments, fecal acid-resistant E. coli counts from cattle fed grain and hay were initially 500,000 and < 100 viable cells per g, respectively. The acid-resistant count of feces incubated in covered cups (room temperature) increased, and the diet-dependent difference was eliminated. After only 2 days, the acid-resistant fecal counts from cattle fed hay and grain were 80 million and 90 million, respectively. Acid-resistant E. coli persisted, and the counts on day 30 were 300,000 and 100,000, respectively. When the cattle feces were placed in shallow pans and allowed to dry at room temperature, the acid-resistant E. coli numbers were low, and on day 10 the hay and grain-fed counts were 300 versus < 100 viable cells per g, respectively. These experiments confirmed the idea that grain-feeding promoted the growth of acid-resistant E. coli in cattle, but this effect did not persist in laboratory incubations. Feces stored in covered containers had high numbers of acid-resistant E. coli regardless of diet, and dried feces from grain-fed cattle had fewer acid-resistant E. coli than feces from hay-fed cattle.