Alessandra Einsfeld Ferreira

Antibiotic-resistant Pseudomonas aeruginosa from hospital wastewater and superficial water: Are they genetically related?

Many studies have reported the presence of antibiotic-resistant Pseudomonas aeruginosa in environmental samples such as hospital wastewater and surface water. The present study evaluated the contribution of untreated hospital wastewater to the dissemination of resistant P. aeruginosa strains in aquatic environments, through the analysis of their antibiotic susceptibility profile and genetic similarity. Wastewater samples were collected from two hospitals located in Rio Grande do Sul, RS, Brazil. Superficial water samples were collected from water bodies that received this wastewater discharge. The antibiotic susceptibility profiles of the strains were determined using the disk-diffusion technique and their genotyping was done by amplification of the Enterobacterial Repetitive Intergenic Consensus sequences (ERIC-PCR). The antibiotic resistance was higher among the hospital wastewater strains and the multiresistant phenotype was also observed only among these strains. The ERIC-PCR profiles did not reveal any genetic similarity among the P. aeruginosa strains from the wastewater and superficial water samples. On the contrary, they showed that genetically distinct populations were established in these different environments and probably that some other contamination source could be contributing to the presence of resistant strains in these water bodies.

Pseudomonas aeruginosa: disseminação de resistência antimicrobiana em efluente hospitalar e água superficial

The aim of this study was to compare sewage samples from Hospital Sao Vicente de Paulo with water samples from the Passo Fundo river, with regard to the susceptibility profile of Pseudomonas aeruginosa isolates, in order to make inferences about the presence of strains of hospital origin in surface water samples. The statistical significance between the susceptibility profiles of the samples was tested using analysis of variance, and the samples were compared by means of contrasts of interest. One hundred and ninety-eight isolates of Pseudomonas aeruginosa were recovered from the samples analyzed. No phenotype for multiresistance was found in the samples from the Passo Fundo river, although some carbapenem-resistant isolates were identified, thereby indicating the presence of contamination with bacteria derived from an environment under strong selection pressure. Significant differences between the water and hospital effluent samples were observed, based on the analysis of variance by means of contrasts of interest. Key-words: Pseudomonas aeruginosa. Bacterial resistance. Surface water. Hospital sewage. nao metabolizadas por pacientes 3 . A ocorrencia de ambientes

Presence of OXA-23-Producing Isolates of Acinetobacter baumannii in Wastewater from Hospitals in Southern Brazil

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.

Characterization of enterocins produced by Enterococcus mundtii isolated from humans feces

The aim of this study was to characterize bacterioc ins produced by 70 strains of Enterococcus mundtii.Four strains exhibited antibiotic activity towards Listeria inno cua , L. monocytogenes , Lactobacillus plantarum , and Salmonella Enteritidis. They remained active under temperature s of up to 121 o C for 20 min, and under pH treatments that varied from 2.0 to 10.0. Antimicrobial activity was maintained during the storage test for 60 days und er freezing. The kinetics of production revealed the peak activi ty of 1600 AU /mL during the logarithmic growth pha se and the molecular weight found was approximately 3.0 kDa. Tion of the products with antimicrob ial activity indicated their proteic nature, presenting a typica l kinetics of primary metabolite and a molecular we ight similar to many purified enterocins.

Spread of Metallo-β-lactamases: screening reveals the presence of a BLA SPM-1 gene in hospital sewage in southern Brazil

Of 396 Pseudomonas aeruginosa strains isolated from hospital sewage, the blaSPM-1 gene was confirmed in nine. This is the first report of environmental P. aeruginosa strains carrying the blaSPM-1 gene in Brazil. The carbapenem resistance, already disseminated among clinical isolates, has been detected among environmental isolates.

Resistência a β-lactâmicos em Acinetobacter spp isolados de efluente hospitalar no sul do Brasil

Acinetobacter spp is an important pathogen that is responsible for nosocomial infections affecting immunocompromised patients, and it can easily acquire resistance to antimicrobial agents. Hospital sewage is an important means for disseminating genes for resistance to antimicrobial agents, to the microbiota of the environment. Within this context, 30 strains of Acinetobacter spp from the sewage of a hospital in Porto Alegre, Rio Grande do Sul, were analyzed regarding their profile of susceptibility to beta-lactams, quinolones and aminoglycosides, by means of an antibiogram and tests to screen for metallo-beta-lactamases and extended-spectrum beta-lactamases. The profile obtained revealed the presence of multidrug-resistant strains and showed that resistance mechanisms such as the production of extended-spectrum beta-lactamases and efflux pumps may be present in these strains.