Hospital sewage in Brazil: a reservoir of multidrug-resistant carbapenemase-producing Enterobacteriaceae

The One Health concept recognizes that human health is clearly linked to the health of animals and the environment. Infections caused by bacteria resistant to carbapenem antibiotics have become a major challenge in hospitals due to limited therapeutic options and consequent increase in mortality. In this study, we investigated the presence of carbapenem-resistant Enterobacteriaceae in 84 effluent samples (42 from hospital and 42 from non-hospital) from Campo Grande, midwest Brazil. First, sewage samples were inoculated in a selective culture medium. Bacteria with reduced susceptibility to meropenem and ertapenem were then identified and their antimicrobial susceptibility was determined using the Vitek-2 system. The blaKPC genes were detected using PCR and further confirmed by sequencing. Carbapenem-resistant Enterobacteriaceae (CRE) were identified in both hospital (n=32) and non-hospital effluent (n=16), with the most common being Klebsiella pneumoniae and of the Enterobacter cloacae complex species. This is the first study to indicate the presence of the blaKPC-2 gene in carbapenem-resistant Enterobacteriaceae, classified as a critical priority by the WHO, in hospital sewage in this region. The dissemination of carbapenem antibiotic-resistant genes may be associated with clinical pathogens. Under favorable conditions and microbial loads, resistant bacteria and antimicrobial-resistance genes found in hospital sewage can disseminate into the environment, causing health problems. Therefore, sewage treatment regulations should be implemented to minimize the transfer of antimicrobial resistance from hospitals.