Bacteroides for Sewage Contamination in Buildings and Water
· Culture methods are available to test for sewage contamination in buildings (M117&M013) as well as new Bacteroides PCR based methods.
· The Bacteroides test has many advantages over the traditional culture tests for total coliforms, fecal coliforms, fecalstreptococci, enterococci, and E.coli tests; including:
o Bacteroides is specific for fecal contamination from all sources–animals, birds, and human
o Coliforms, E.coli, fecalstreptococci, and enterococci can grow in water, soil, sediments and on vegetation in uncontaminated environments. (E.coli is found in pristine tropical environments.)
o Bacteroides will not multiply in the environment.
o Bacteroides out number coliforms by1.000:1and out number E.coli by10,000:1; therefore, the chance of finding Bacteroides is greatly enhanced.
o Traditional culture based tests rely on the presence of live bacteria. Unfortunately these bacteria often will not be viable in indoor environments. THIS MEANS THAT A NEGATIVE COLIFORM or E.COLI RESULT DOES NOT MEAN THE ABSENCE OF FECALCONTAMINATION. The new Bacteroides test overcomes this limitation since PCR is used. The laboratory can detect live, nonviable, or viable but not culturable bacteria.
o Using Total Bacteroides (M095), it is now possible to estimate the amount of fecal contamination from non-human and human sources.
1. Obtain a sterile1mL Butterfield’s Solution swab (EMSL Product ID 8708935) to collect and transport samples (provided at your request by EMSL).
2. With gloves on, remove swab from sterile packaging.
3. Carefully unscrew cap of sampling device–swab is attached to the lid of the cap.
4. Gently press out excess solution from sampling swab by pressing the swab against the inside wall of the tube with a rolling motion.
5. Hold swab at an approximate 30° angle from the sampling surface, taking care not to contaminate any part of the swab or the sampling site.
6. Using firm, even pressure move the swab slowly and thoroughly over an entire 4"x4" sampling area, rewetting the swab tip with the Neutralizing Solution as needed. First horizontally, then vertically.
7. After sampling is complete, carefully put swab back into vial and close cap tight.
8. Label the sample using a permanent ink marker.
9. Background samples in non-fecally contaminated are as should be taken. Sample Shipping
a. There are no special shipping requirements since Bacteroides will not multiply outside of the intestine.
b. There is no hold time. However, do not store sample longer than a month before analysis.