Caracterização fenotípica e genotípica de Salmonella enterica de origem avícola e atividade antimicrobiana de extratos de própolis

• Autor(a) principal: Benicio, Cristyene Gonçalves
• Data de Publicação: 2019
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/10275
• topic: Antibiograma; Bactericida; Bacteriostático; Resistência e sorotipificação; Antibiogram; Bactericidal; Bacteriostatic; Resistance and serotyping; CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS

The objective of this study was to characterize phenotypically and genotypically Salmonella isolates from food and environmental samples, as well as to evaluate the in vitro antibiotic action of green and red propolis extracts. The 128 isolates of Salmonella enterica were obtained and analyzed for antimicrobial susceptibility by disk diffusion method. The antimicrobials and microgram concentrations tested were: amoxicillin-clavulanic acid (30μg), cotrimoxazole (trimetropim-sulfamethoxazole) (25μg), ciprofloxacin (5μg), enrofloxacin (5μg), ceftiofur (30μg), chloramphenicol (30μg), chloramphenicol (30μg) and doxycycline (30μg). Salmonella Enteritidis (ATCC 13076), Salmonella Typhimurium (ATCC 14028) and Escherichia coli (ATCC 25922) strains were used as a quality control of the sensitivity tests. Two genes of virulence and nine of resistance were searched. Among the 128 isolates, 40 were tested against propolis action. Propolis extracts diluted in ethanol were evaluated for their antimicrobial activity ranging from 0.2 to 100 mg/mL-1 by determining the minimum inhibitory and bactericidal concentration. We found 27 different serotypes, the most common was Salmonella Heidelberg, Saintpaul, Typhimurium and Minnesota. It was found that 85.2% (109/128) of the isolates were resistant to one or more antimicrobial agents used and only five serotypes showed no resistance. We identified 54 multiresistant isolates. Of the eight antimicrobials evaluated, for two of them (chloramphenicol and phosphomycin) all isolates were susceptible and the one with the largest number of resistant isolates was ciprofloxacin. Among the resistance genes evaluated (blaCTX-M and gyrA), about 70% (89/128) of the isolates harbored it. Regarding virulence genes, three (invA, hilA and sseD) were identified in all isolates tested. For the other six, spvR presented the highest number of isolates in which it was not identified. Of the 18 different serotypes tested against antibiotic action of propolis, the most susceptible were Salmonella Senftenberg and the most resistant: Agona, Braenderup, Heidelberg, Children, Minnesota, Schwarzengrund, Newport, Orion, Saintpaul and Anatum. In general, the lowest inhibitory and minimum bactericidal concentration values were 3.1 mg/mL and 6.25 mg/mL, respectively. The best antimicrobial action was for red propolis, regardless of the type of extraction used to obtain the extracts. Thus, propolis may be a viable alternative as antimicrobial under Salmonella sp because it it has expressive action potential. Seeking alternatives for the treatment and control of pathogenic microorganisms has been important through the emergence of multiresistant strains.