Development of Escherichia coli based gene expression profiling of sewage sludge leachates.

Aims The impact of municipal waste on pathogenic micro-organisms released into the environment is a public health concern. This study aims to evaluate the effects of sewage sludge and antibiotic contaminants on stress response, virulence and antibiotic resistance in a pathogenic Escherichia coli. Methods and ResultsConclusionsThe effects of sewage sludge leachates on uropathogenic E.coli CFT073 were determined by monitoring the expression of 45 genes associated with antibiotic/metal resistance, stress response and virulence using RT-qPCR. The E.coli gene expression was validated using subinhibitory concentrations of tetracycline and ciprofloxacin. E. coli exposed to sewage sludge or sewage sludge+fly ash leachates altered the expression of five antibiotic and metal resistance, three stress response and two virulence-associated genes. When antibiotics were combined with sludge or sludge+fly ash the antibiotic-associated gene expression was altered. E. coli treated with two sludge leachates had distinct gene expression patterns that were altered when the sludge leachates were combined with tetracycline, although to a lesser extent with ciprofloxacin. Significance and Impact of the StudyThe E.coli multigene expression analysis is a potential new tool for assessing the effects of pollutants on pathogenic microbes in environmental waters for improved risk assessment.