Genes encoding antibiotic modifying enzymes conferring resistance against aminoglycosides in bacteria: Their identification and detection from wastewater.

Global reporting of antibiotic resistant bacteria (ARB) bearing antibiotic resistance genes (ARGs) have increased in the past decade. Sewage systems act as breeding grounds for these pathogens. Dumping of untreated sewage effluent in river water systems have aided in their dissemination and spread. The molecular pathways circumventing antibiotics through ARGs is rising owing to overuse of these drugs. Use of aminoglycoside spectrum drugs has been increased exponentially. The genes providing resistance to these antibiotics are transferred through extra-chromosomal circular DNA elements. Polluted water bodies are ground zero for exchange of these genetic factors. Through literature survey, we shortlisted some clinically relevant genes which provide resistance against aminoglycosides and hold immense importance in present scenario. Initial screening for these genes was done on water samples collected from Swarna Rekha River channel in Gwalior District of Madhya Pradesh, India. A total of five identified genes were sequence verified using conventional PCR followed by targeted sequencing. Further, diagnostic platforms were designed for two reoccurring genes npmA & sat4^A and their presence evaluated from wastewater samples collected from urban establishments of the district. Prevalence of these genes in sewage samples validated the broad impact of urban waste burden in polluting local water bodies. We were able to identify some indispensable and high risk aminoglycoside resistance providing genes, unreported in Indian context. This approach towards ARG screening could support risk assessment of future antibiotic resistance associated public health hazards.