Escherichia coli detection using mTEC agar and fluorescent antibody direct viable counting on coastal recreational water samples.
OBJECTIVE
Escherichia coli is the faecal indicator species recommended by the US Environmental Protection Agency (USEPA) for monitoring fresh recreational water. Viable but nonculturable (VBNC) E. coli are living cells that are dormant and not culturable using standard microbiological cultivation methods. This study reports a comparison between the mTEC culture method recommended by USEPA for E. coli enumeration and a fluorescent antibody-direct viable count (FA-DVC) method to visualize living E. coli cells with a microscope.


RESULTS
Escherichia coli, faecal coliforms and Enterococcus were detected using standard methods recommended by the USEPA. VBNC E. coli was visualized with FA-DVC. Results were analysed with standard statistical methods (Pearson correlation; paired-sample t-test). Significantly higher numbers of E. coli were detected using the FA-DVC method than using the mTEC method. Escherichia coli results were also compared with faecal coliform (mFC broth) and Enterococcus (mEI agar) counts in the same samples.


CONCLUSIONS
The results of this comparative study demonstrate that E. coli can be present in higher numbers than what are detected with standard culture methods.


CONCLUSIONS
This study re-emphasizes the need for a rapid, accurate and precise method for detecting health risks to humans who use recreational waters.
Zimmerman
A M
AM
The University of Southern Mississippi, Gulf Coast Research Laboratory, Ocean Springs, MS, USA.
Rebarchik
D M
DM
Flowers
A R
AR
Williams
J L
JL
Grimes
D J
DJ
D015169:Colony Count, Microbial / Q000379:methods*; D004926:Escherichia coli / Q000254:growth & development / Q000302:isolation & purification*; D019085:Fluorescent Antibody Technique, Direct / Q000379:methods*; D050296:Microbial Viability; D012623:Seawater / Q000382:microbiology*