Genetic Diversity and Antimicrobial Resistance of Escherichia coli from Human and Animal Sources Uncovers Multiple Resistances from Human Sources

• Published in: PloS one 2011-06, Vol.6 (6), p.e20819
• Main Authors: Ibekwe, A. Mark, Murinda, Shelton E, Graves, Alexandria K, Carter, Dee A
• Format: Article
• Language: English
• Subjects: Agricultural management; Agricultural runoff; Agriculture; Animals; Anti-Infective Agents - pharmacology; antibiotic resistance; Antibiotics; Antiinfectives and antibacterials; Antimicrobial agents; Antimicrobial resistance; Bacteria; Biodiversity; Biology; California; Channels; Contamination; Creeks; Disease susceptibility; Drug Resistance, Bacterial - genetics; Drug Resistance, Multiple - genetics; E coli; Erythromycin; Escherichia coli; Escherichia coli - drug effects; Escherichia coli - genetics; Escherichia coli - isolation & purification; Fecal coliforms; Food Microbiology; Gel electrophoresis; Genetic aspects; Genetic diversity; Genetic Variation; genotype; Genotypes; Geologic Sediments - microbiology; health promotion; Housing; Humans; Microbial drug resistance; Parks & recreation areas; Phenotype; planning; Pollution sources; Populations; Public health; Pulsed-field gel electrophoresis; Quality management; rifampicin; Rifampin; River channels; Rivers; Rivers - microbiology; Runoff; Salmonella; sediment; Sediments; Sediments (Geology); Streams; Suidae; Surface runoff; Surface water; tetracycline; Urban areas; Urban runoff; Water pollution; Water quality; Water quality management; Water resource management; Water resources; Watersheds
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0020819

Escherichia coli are widely used as indicators of fecal contamination, and in some cases to identify host sources of fecal contamination in surface water. Prevalence, genetic diversity and antimicrobial susceptibility were determined for 600 generic E. coli isolates obtained from surface water and sediment from creeks and channels along the middle Santa Ana River (MSAR) watershed of southern California, USA, after a 12 month study. Evaluation of E. coli populations along the creeks and channels showed that E. coli were more prevalent in sediment compared to surface water. E. coli populations were not significantly different (P = 0.05) between urban runoff sources and agricultural sources, however, E. coli genotypes determined by pulsed-field gel electrophoresis (PFGE) were less diverse in the agricultural sources than in urban runoff sources. PFGE also showed that E. coli populations in surface water were more diverse than in the sediment, suggesting isolates in sediment may be dominated by clonal populations.Twenty four percent (144 isolates) of the 600 isolates exhibited resistance to more than one antimicrobial agent. Most multiple resistances were associated with inputs from urban runoff and involved the antimicrobials rifampicin, tetracycline, and erythromycin. The occurrence of a greater number of E. coli with multiple antibiotic resistances from urban runoff sources than agricultural sources in this watershed provides useful evidence in planning strategies for water quality management and public health protection.