Antibiotic resistance profiles ofEscherichia coliisolated from rural and urban environments

Abstract
Sludge and waste water samples from a variety of locations (in the United States and from one location in Mexico) were evaluated to determine whether multiple antibiotic resistant resistance patterns correlated with location and type of waste. The occurrence of antibiotic resistant strains of Escherichia coli was dependent upon site among the eleven locations sampled (P < 0.001). The E. coli strains from digested municipal sewage sludge from El Paso, Texas and those from an El Paso army hospital were resistant to the widest range of antibiotics and were resistant to a greater number of antibiotics than any other site (P < 0.01). When isolates from undigested waste water samples were analyzed, there was no significant difference (P ≥ 0.05) between those obtained from two neighboring cities located on either side of the US‐Mexico border. There was no significant difference in the number of antibiotics to which isolates were resistant when comparing digested sewage sludge samples from rural and urban areas. This suggests that the digestion process does select from a common set of resistance markers in E. coli strains. Overall, it does not appear that antibiotic resistance patterns of isolated E. coli strains could be used to categorize waste water samples.