Role of glucose in enhancing the temperature-dependent growth inhibition of Escherichia coli O157:H7 ATCC 43895 by a Pseudomonas sp.
Growth of Escherichia coli O157:H7 strain ATCC 43895 was monitored at 5, 10, 15, and 25 degrees C in both pure and mixed (1:1) cultures with a gluconate-producing Pseudomonas sp. found in meat to evaluate the effect of the absence and presence of 1% glucose in broth on temperature-dependent competition. The number of colonies of the Pseudomonas strain exceeded 9 log CFU/ml under all conditions tested. The pathogen grew better as the temperature increased from 10 to 15 and 25 degrees C and grew better in pure culture than in mixed cultures. Pseudomonas sp. inhibited E. coli O157:H7 in cocultures with glucose at 10 degrees C, while at 15 degrees C the pathogen exhibited a biphasic pattern of growth with an intermediate inactivation period. Pathogen inhibition was much weaker in cocultures grown without glucose at 10 to 15 degrees C and, irrespective of glucose, at 25 degrees C. These results indicate that glucose enhances the growth inhibition of E. coli O157:H7 by some Pseudomonas spp., potentially due to its rapid uptake and conversion to gluconate, at low (< or = 15 degrees C) temperatures.
Samelis
John
J
Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523, USA.
Sofos
John N
JN
D000898:Antibiosis; D018929:Cell Culture Techniques; D019453:Escherichia coli O157 / Q000254:growth & development / Q000502:physiology*; D005947:Glucose / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D011549:Pseudomonas / Q000254:growth & development / Q000502:physiology*; D013696:Temperature
D005947:Glucose