Tertiary hospital sewage as reservoir of bacteria expressing MDR phenotype in Brazil.

G S Zagui,K A A Tonani,G P Machado,T V Silva,S I Segura-Muñoz,B M Fregonesi,L N Andrade,D Andrade

doi:10.1590/1519-6984.234471

Abstract

High doses of antibiotics used in hospitals can affect the microbial composition of sewers, selecting resistant bacteria. In this sense, we evaluated the antibiotic resistance profile and the multiresistant phenotype of bacteria isolated in sewage from a tertiary hospital in the interior São Paulo state, Brazil. For bacteria isolation, 10 µL of sewage samples were sown in selective culture media and the isolates were identified using VITEK-2 automatized system. The antibiotic sensitivity test was performed by disk diffusion. High percentages of resistance were found for amoxicillin, ampicillin, ceftazidime, clindamycin, vancomycin and the multidrug-resistant phenotype (MDR) was attributed to 60.7% of the isolates. Our results show bacteria classified as critical/high priority by WHO List of Priority Pathogens (Enterococcus and Staphylococcus aureus resistant to vancomycin and Enterobacteriaceae resistant to carbapenems) in hospital sewage. Therefore, the implementation of disinfection technologies for hospital sewage would reduce the bacterial load in the sewage that will reach urban wastewater treatment plants, minimizing superficial water contamination and bacterial resistance spread in the environment.

Highlights

European Center for Disease Prevention and Control (ECDC), the Center for Disease Control and Prevention (CDC) and international experts’ groups established a worldwide terminology for acquired resistance profiles of several bacteria responsible for human infections (e.g., Staphylococcus aureus, Enterococcus spp., Enterobacteriaceae family, Pseudomonas aeruginosa and Acinetobacter spp.)
Among the Gramnegative bacteria, 62.5% were classified as multidrug-resistant phenotype (MDR) and six isolates presented resistance to at least ten antibiotics (E. cloacae Complex (1), H. alvei (2), K. ozaenae (2) and K. pneumoniae (1))
Wastewater composition varies according to local activities, most sewage microbial composition comes from gastrointestinal tract (Abdulhaq and Basode, 2015) and, from this perspective, most bacteria identified in this study can be found in human intestinal microbiota, as well as infections

Summary

Introduction

European Center for Disease Prevention and Control (ECDC), the Center for Disease Control and Prevention (CDC) and international experts’ groups established a worldwide terminology for acquired resistance profiles of several bacteria responsible for human infections (e.g., Staphylococcus aureus, Enterococcus spp., Enterobacteriaceae family, Pseudomonas aeruginosa and Acinetobacter spp.). The multidrug-resistant phenotype (MDR) has been defined. There are no maximum limits established for antibiotics and resistant pathogens in most countries (Carraro et al, 2016). Evidence suggests that UWWTP are antibiotic resistance reservoirs and contribute to their dissemination in water resources (Rizzo et al, 2013; Auguet et al, 2017). In Brazil, few studies have addressed this issue and, considering the aspects mentioned above, evidence is needed to support new guidelines for hospital sewage treatment establishing. The present study aims to evaluate the prevalence of multiresistant phenotype (MDR, XDR and PDR) in bacteria from tertiary hospital sewage in Brazil

Methods

Results

Conclusion