Presence of OXA-23-Producing Isolates ofAcinetobacter baumanniiin Wastewater from Hospitals in Southern Brazil

Abstract

The aim of the study was to evaluate the dissemination of multiresistant isolates of Acinetobacter baumannii carrying resistance genes, by samples of wastewater from hospitals in Porto Alegre, Rio Grande do Sul, Brazil. We obtained 303 bacterial isolates from the wastewater of three hospitals in Porto Alegre, Rio Grande do Sul. For each isolate, we determined the profile of susceptibility to antimicrobials and the presence of the genes bla(OXA-23), bla(OXA-24), bla(OXA-51), bla(OXA-58), bla(SPM-1), bla(IMP), and bla(VIM.) The bla(OXA-51) gene was found in 56% of the isolates, indicating the presence of A. baumannii in this environment. Of these, three multiresistant isolates were positive for the bla(OXA-23) gene, in wastewater from two of the hospitals. The results obtained in this study indicate that isolates of A. baumannii which are multiresistant and carry resistance genes such as bla(OXA-51) and bla(OXA-23) are being released into the environment in the wastewater from the hospitals analyzed. Multiresistant Acinetobacter junii, the newly emerging pathogen, were also found among the multiresistant isolates. Hospital wastewater may be crucial to the development and dispersal of multiresistant bacteria, making waterbodies reservoirs of bacterial resistance.

Occurrence of an Environmental Acinetobacter baumannii Strain Similar to a Clinical Isolate in Paleosol from Croatia

“…While it is certainly true that A. baumannii can be isolated from patients and hospital environmental sources during outbreaks, this species has no known natural habitat outside the hospital (29). Multiresistant isolates of A. baumannii have been found in wastewater from hospitals in Brazil (30). A. baumannii has also been isolated from hospital solid waste (31).…”

Carbapenem-resistant bacteria in a secondary wastewater treatment plant

“…Isolates of CRBP were recovered from hospital wastewaters worldwide (Ferreira et al, 2011;Zhang et al, 2013;Chandran et al, 2014). The prevalence of isolated CRBP in particular Recently, a fluorogenic heterotrophic plate count method was developed for detection of the broad range of carbapenemresistant bacteria in drinking water (Tanner et al, 2015).…”

“…isolates by disc-diffusion tests. The MICs values were confirmed using AST-XN05 and AST-N233 testing card for Vitek2 system, and interpreted according to the European Committee on Antimicrobial Susceptibility Testing criteria (EUCAST, 2014).…”

“…Published papers on CRBP in nature are mostly focused on single bacterial isolates. Viable isolates of CRBP were recovered from hospital sewage both before and after disinfection (Ferreira et al, 2011;Chagas et al, 2011;Zhang et al, 2013;Chandran et al, 2014). From the mixture of domestic and hospital wastewaters two carbapenem-resistant Klebsiella pneumoniae and one Escherichia coli were recovered (Galler et al, 2014).…”

“…Therefore, the numbers of viable CRBP in wastewater remain to be determined, in order to quantify the influence of wastewater on the spread of CRBP in the environment. Moreover, the temperature at which the CRBP 35-37°C (Girlich et al, 2010;Ferreira et al, 2011;Walsh et al, 2011;Galler et al, 2014;Tanner et al, 2015) or was not specified at all (Chagas et al, 2011;Poirel et al, 2012;Picao et al, 2013;Zhang et al, 2013). Cultivation at 37°C allows for the isolation of intrinsically carbapenem-resistant bacteria which are autochthonous populations in environmental samples.…”