Changes in Antibiotic Resistance Patterns ofEscherichia coliduring Domestic Wastewater Treatment

Abstract

Changes in antibiotic resistance of Escherichia coli in the different stages of conventional domestic wastewater treatment were investigated. Over two years, more than 3500 E. coli isolates from four stages of the wastewater treatment process were tested for resistance to six different antibiotics. The percent resistance of bacteria from any of the stages was highly variable in different samples. Because of this variability, no statistically significant difference was found in the overall percent resistance of E. coli from influent to effluent. When comparing different stages within samples, however, there seemed to be an increase in resistance to ampicillin and amoxicillin between the raw influent and primary effluent. In addition, the percent of isolates with multiple antibiotic resistance, resistant to more than one and less than five antibiotics, and highly multiple antibiotic resistance, resistant to at least five antibiotics, increased through the treatment process. Water Environ. Res., 81, 878 (2009).

Antimicrobial resistant coliform bacteria in the Gomti river water and determination of their tolerance level

“…The resistance levels of E. coli and Enterobacter spp. populations are also comparable to those found by other authors [32– 34]. Resistance patterns in the population of coliforms were recorded as erythromycin> amoxicillin > tetracycline> ciprofloxacin> penicillin, tetracycline >erythromycin >ciprofloxacin >amoxicillin >penicillin and tetracycline >ciprofloxacin >amoxicillin >erythromycin >penicillin from site I, II and site III respectively.…”

“…found that more than 56% of the Gram negative bacteria from cultivated marine sediment were resistant to 5 or more antibiotics. Lefkowitz and Durán [34] measured the multi-resistance of E. coli in wastewater treatment plants, obtaining outflow readings of 60% of bacteria multi-resistant to 2 or more antibiotics and 25% to 4 or more. Other authors have studied the same factor [36], and the findings of this study fall within the same ranges found therein.…”

Activated Sludge and Other Aerobic Suspended Culture Processes

“…A mathematical basis to compute the production capacity of these determinants in the activated sludge process is provided. Lefkowitz and Duran [35] investigated changes in antibiotic resistance of Escherichia coli in different stages of conventional domestic wastewater treatment. More than 3500 E. coli isolates from the wastewater treatment process were tested for resistance to six different antibiotics.…”

Antimicrobial Resistance Genes and Wastewater Treatment

“…As part of aquatic ecosystems, urban wastewater treatment systems (collecting sanitary sewage, hospital effluents, and storm water runoff ) possess all the components required to ensure the acquisition of all varieties of resistance genes. The antimicrobials present in wastewater due to incomplete degradation by humans and animals, disposal of unused drugs, and runoff losses from land application, together with environmental and pathogenic bacteria in nutrient-rich engineered systems, provide all the necessary requirements to support a breeding ground for horizontal gene transfer and the propagation of resistance genes (Davies and Davies, 2010;Ferreira da Silva et al, 2006;Kim and Aga, 2007;Lefkowitz and Duran, 2009).…”

“…In these studies, resistance profiles of pathogenic population subsets of bacterial communities downstream of the effluent discharge were studied. (Lefkowitz and Duran, 2009;Akiyama and Savin, 2010;Zhang et al, 2009).…”