Centennial Honors College
Western Illinois University
Undergraduate Research Day 2012
Poster Presentation
Antibiotic Susceptibility Testing of Escherichia coli Thermotolerant Coliforms
(KEC) Isolated from Streams That feed into the Mississippi River in Hancock
County, Illinois
Morris Parker
Faculty Mentor: Wendell French
Biology
The number of thermotolerant coliform bacteria present in water determines fecal
pollution. During a three month period (June 2010-August 2010) Dr. Wendell French
and Thomas Crenshaw collected 54 samples from seven different streams that all feed
into the Mississippi. These samples were aseptically collected from the eight streams
sites labeled A-G. Each sample was diluted serially from 10-1 to 10-5 dilution in sterile
water flasks to generate fewer colonies per sample media for easier counts of the
colonies. The samples were filtrated using the membrane filtration technique and placed
on CHROMagarECC (ECC) and incubated at both 41oC and 44.5oC to determine the
optimum growth temperature of thermotolerant coliforms (Crenshaw, 2011; Alonso et
al., 1999). After a 24-hour incubation period, the cultures were removed and
enumerated. This was done to determine the optimum growth temperature of the
thermotolerant coliforms (Crenshaw, 2011; Alonso et al., 1999) Since the degree of
susceptibility of microorganism vary in between species and strains (Tortora et al.,
2007). It is important that the isolates collected from the Mississippi be tested with
antibody susceptibility test. The main objective of our study is to determine the level of
sensitivity/resistance as well as multidrug resistance among the different strains of E.
coli isolated from a previous study of this experiment. The reference strain of E. coli
(ATC8739) will be used as a negative control for comparison.