What do fecal coliforms indicate in tropical waters
High densities of total and fecal coliform bacteria have been detected in pristine streams and in ground water samples collected from many tropical parts of the world, even in epiphytic vegetation 10 m above ground in the rain forest of Puerto Rico. Nucleic acid (DNA) analyses of Escherichia coli from pristine tropical environs has indicated that they are identical to clinical isolates of E. coli. Many tropical source waters have been shown to have enteric pathogens in the complete absence of coliforms. Diffusion chamber studies with E. coli at several tropical sites reveal that this bacterium can survive indefinitely in most freshwaters in Puerto Rico. An evaluation of methods for the enumeration of fecal coliforms showed that currently used media have poor reliability as a result of large numbers of false positive and false negative results when applied to tropical water samples. Total and fecal coliform bacteria are not reliable indicators of recent biological contamination of waters in tropical areas. Fecal streptococci and coliphages in tropical waters, violate the same under lying assumptions of indicator assays as the coliforms. Anaerobic bacteria like Bifidobacterium spp. and Clostridium perfringens show some promise in terms of survival but not in ease of enumeration and media specificity. The best course at present lies in using current techniques for direct enumeration of pathogens by fluorescent staining and nucleic acid analysis and developing tropical maximum containmant levels for certain resistant pathogens in tropical waters. 66 refs.
- Research Organization:
- Savannah River Lab., Aiken, SC (USA)
- DOE Contract Number:
- AC09-76SR00001
- OSTI ID:
- 6902510
- Report Number(s):
- DP-MS-88-5; CONF-880830-1; ON: DE88006507
- Resource Relation:
- Conference: 1. biennial symposium of water quality, Alberta, Canada, 29 Aug 1988
- Country of Publication:
- United States
- Language:
- English
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99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
BACTERIAL DISEASES
BIOLOGICAL INDICATORS
GEOGRAPHICAL VARIATIONS
EVALUATION
COLIFORMS
ESCHERICHIA COLI
FLUORESCENCE
GROUND WATER
PUERTO RICO
SURFACE WATERS
TROPICAL MEDICINE
TROPICAL REGIONS
BACTERIA
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FEDERAL REGION II
GREATER ANTILLES
HYDROGEN COMPOUNDS
INFECTIOUS DISEASES
ISLANDS
LUMINESCENCE
MEDICINE
MICROORGANISMS
NORTH AMERICA
OXYGEN COMPOUNDS
USA
VARIATIONS
WATER
WEST INDIES
550700* - Microbiology
552000 - Public Health