Assessment of Dissemination and Removal of Antimicrobial Resistance Genes after Wastewater Secondary and Tertiary Treatments in the city of São Paulo

• Grant number: 16/06469-9
• Support Opportunities: Regular Research Grants
• Start date: February 01, 2017
• End date: January 31, 2019
• Field of knowledge: Health Sciences - Collective Health - Public Health
• Principal Investigator: Milena Dropa
• Grantee: Milena Dropa
• Host Institution: Faculdade de Saúde Pública (FSP). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated researchers: Maria Ines Zanoli Sato ; Nilton Erbet Lincopan Huenuman ; Ronalda Silva de Araújo ; Terezinha Knöbl

Abstract

Bacterial resistance is facilitated by a selective pressure of antimicrobial use in clinical practice and other activities, such as agriculture and livestock, and can be disseminated to the nature by means of inadequate sewage release. Resistance encoding genes are disseminated through various genetic elements such as integrons and transposons mobilized by plasmids. The objective of this project is to evaluate the presence of genes encoding class 1 integrons and resistance to ²-lactam compounds and fluoroquinolones in sewage samples from livestock farms, human and veterinary hospitals, and a sewage treatment plant that receives and treats these wastes, including raw and treated sewage. Samples will be collected monthly for a year, and concentrated in membranes. After DNA extraction of cultured and non-cultured samples, extended spectrum ²-lactamase-encoding blaCTX-M genes, and plasmid quinolone resistance-encoding qnr genes, will be detected and quantified by real-time PCR. Conventional PCR and sequencing will be carried out for the detection and identification of these and other resistance genes in samples. The main scientific challenge for this project will be the application of real-time quantitative PCR for antimicrobial resistance genetic determinants in non-cultured samples, providing a tool that can be useful in future evaluations of these emerging contaminants in the environment. The expected results for this study are to elucidate which genes are spread by each kind of sample, and to verify if sewage secondary and tertiary treatments can reduce and/or remove resistance genetic markers before reuse or release into water supplies. (AU)