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item Ibekwe, Abasiofiok - Mark

Submitted to: Environmental Science and Technology
Publication Type: Proceedings
Publication Acceptance Date: 9/1/2004
Publication Date: 1/1/2005
Citation: Ibekwe, A.M., Lyon, S. 2005. Impact of dairy production on microbial characteristics through drinking water aquifer material. In: Proceedings of First International Conference on Environmental Science and Technology, January 23-26, 2005, New Orleans, Louisiana. 1:215-221.

Interpretive Summary: Pollution in the form of sewage from human populations, or from livestock in agricultural operations, can lead to elevated levels of microbial contamination in drinking and recreational water resources. These microbes remain a major cause of illness and death worldwide, particularly in developing nations. Issues of water quality are a global problem with potentially devastating results if microbial levels are not monitored and controlled effectively. In this study, the concentrations of different bacterial species such as heterotrophic bacteria, Escherichia coli, and Enterococcus were determined after running tertiary water from Santa Ana River through through the aquifer material for 15 days. The Enterococcus group and E. coli are major contributors to poor water quality world-wide. Confirmation of Escherichia coli and Enterococcus spp by polymerase chain reaction (PCR) was more accurate than confirmation by biochemical test. Therefore, PCR offers a rapid and sensitive method of bacterial detection in water samples and can be adopted as an effective diagnostic tool for monitoring microbiological water quality, through coliform quantification, and detection of other waterborne microbial pathogens.

Technical Abstract: Public health concerns about pathogens present in animal manure are emerging constraints to water supplies in many areas of the world. The aim of this study was to examine microbial community composition in aquifer material in an effort to understanding key processes that control the growth and mobility of pathogens through aquifer sediment. Enterococcus faecalis primers targeted the ddl gene which encodes the D-Ala : D-Ala ligase and produces a 941 DNA base pair product upon amplification and primers for E. faecium which produce a 658 DNA base pair product were used to identify the two species in the samples. Total microbial community profiles were compared using eubacterial primers to amplify 16S rRNA genes from total bacterial DNA and RNA. PCR and reverse transcriptase (RT) PCR were used to amplify 16S ribosomal RNA, and the products were subjected to denaturing gradient gel electrophoresis (DGGE). The PCR assay with the ddl gene was 100% accurate. The biochemical test overestimated the percentage of E. faecium in our samples. A more detailed analysis with sequencing of 16S rRNA fragments showed a wide variety of cells from source water initially attached to the aquifer materials and resulted in species richness. At the end of the experimental period, the biofilm entered a stable population state, which was characterized by a greater richness of viable bacteria as determined by RT-PCR-DGGE.