Bacterial interference with coliform colony sheen production on membrane filters.
AUTOR(ES)
Burlingame, G A
RESUMO
The membrane filter (MF) method for detection and enumeration of coliform bacteria in drinking water requires that the coliforms both grow and produce a green metallic sheen when the filter is incubated on modified Endo medium at 35 degrees C for 22 h. Large numbers of noncoliform bacteria, which are enumerated by the standard plate count (SPC) technique, can interfere with the detection of coliforms on MF. This paper presents quantitative evidence from laboratory experiments on the interference of specific SPC bacteria on coliform colony sheen production on MF. Pseudomonas aeruginosa and Aeromonas hydrophila caused significant reductions in Escherichia coli sheen colony counts when present at 3,000 and 220 per filter, respectively. The Flavobacterium sp. and Bacillus sp. selected for this study from SPC did not interfere with coliform colony sheen production. Excessive crowding of E. coli and Enterobacter cloacae colonies on MF also caused a reduction in the number of colonies that produced sheen. Even when there was no crowding (14 colonies per filter), only a fraction of the E. cloacae colonies produced sheen colonies on modified Endo medium.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=239611Documentos Relacionados
- Humic acid interference with virus recovery by electropositive microporous filters.
- Comparison of the surface structure, metal binding, and fecal coliform recoveries of nine membrane filters.
- Improved technique for staining bacteria on membrane filters.
- A rapid procedure for colony screening using nylon filters.
- Influence of Coliform Source on Evaluation of Membrane Filters