Clonal Populations of Thermotolerant Enterobacteriaceae in Recreational Water and Their Potential Interference with Fecal Escherichia coli Counts
AUTOR(ES)
McLellan, Sandra L.
FONTE
American Society for Microbiology
RESUMO
Bacterial strains were isolated from beach water samples using the original Environmental Protection Agency method for Escherichia coli enumeration and analyzed by pulsed-field gel electrophoresis (PFGE). Identical PFGE patterns were found for numerous isolates from 4 of the 9 days sampled, suggesting environmental replication. 16S rRNA gene sequencing, API 20E biochemical testing, and the absence of β-glucuronidase activity revealed that these clonal isolates were Klebsiella, Citrobacter, and Enterobacter spp. In contrast, 82% of the nonclonal isolates from water samples were confirmed to be E. coli, and 16% were identified as other fecal coliforms. These nonclonal isolates produced a diverse range of PFGE patterns similar to those of isolates obtained directly from untreated sewage and gull droppings. β-Glucuronidase activity was critical in distinguishing E. coli from other fecal coliforms, particularly for the clonal isolates. These findings demonstrate that E. coli is a better indicator of fecal pollution than fecal coliforms, which may replicate in the environment and falsely elevate indicator organism levels.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=93254Documentos Relacionados
- Comparison and Recovery of Escherichia coli and Thermotolerant Coliforms in Water with a Chromogenic Medium Incubated at 41 and 44.5°C
- Epidemiological relatedness and clonal types of natural populations of Escherichia coli strains producing Shiga toxins in separate populations of cattle and sheep.
- Comparison of thermotolerant coliforms and Escherichia coli densities in freshwater bodies
- Evaluation of Coli-Count Samplers for Possible Use in Standard Counting of Total and Fecal Coliforms in Recreational Waters
- Elevated Fecal Candida Counts in Patients with Antibiotic-Associated Diarrhea: Role of Soluble Fecal Substances