Sewage from a secondary hospital in Ribeirão Preto, southeastern Brazil: a source of multidrug-resistant Enterobacteriaceae

Antimicrobial resistance is one of the severe threats to global health. Hospital sewage can serve as a reservoir for multi-resistant bacteria and promote the spread of antimicrobial resistance. This study aimed to investigate the antimicrobial susceptibility and the pathogenic potential of Enterobacteriaceae isolated from the sewage of a secondary hospital in Ribeirão Preto, a city in southeastern Brazil. The strains were isolated by membrane filtration and identified by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF). The antimicrobial susceptibility profile was performed by disk diffusion. Polymerase chain reaction (PCR) assays were used to detect virulence genes among the strains. Twenty-eight isolates were obtained, with Klebsiella pneumoniae being the predominant species (71.4%, n = 20). All isolates were classified as multidrug-resistant, including four isolates that were non-susceptible to at least 50% of the tested antibiotics. All isolates were also non-susceptible to cefuroxime and sulfonamides antibiotics; however, they were susceptible to norfloxacin, ofloxacin, amikacin, gentamicin, netilmicin, ertapenem, cefazolin, cefaclor, and cefotetan. The virulence genes ycf M, fim H, mrk D, kfu , and ent B were detected in several isolates. Our study showed that even in a secondary hospital, without the routine of major surgeries and intensive care admissions, the hospital sewage can harbor a high percentage of multidrug-resistant bacteria with pathogenic potential. This leads to the worrying risk of public health and environmental contamination.