TSST-1, enterotoxin and bacteriocin-like substance production by Staphylococcus aureus isolated from foods

Abstract

The production of Toxic Shock Syndrome Toxin-1 (TSST-1), enterotoxins and bacteriocin-like substances was evaluated in 95 strains of Staphylococcus aureus recovered from raw bovine milk (n=31) and from food samples involved in staphylococcal food poisoning (n=64). Enterotoxigenicity tests with the membrane over agar associated to optimal sensibility plate assays were performed and showed that 96.77% of strains recovered from milk and 95.31% from food samples produced enterotoxins A, B, C, D or TSST-1. Reference strains S. epidermidis, Bacillus cereus, Listeria monocytogenes, Lactobacillus casei, Pseudomonas aeruginosa, S. aureus, Salmonella Typhimurium, Escherichia coli, Enterococcus faecalis and Bacteroides fragilis were used as indicator bacteria in the antagonistic assays, the first five being sensitive to antagonistic substances. Brain heart infusion agar, in pH values ranging from 5.0 to 7.0 in aerobic atmosphere showed to be the optimum condition for antagonistic activity as evaluated with the best producer strains against the most sensitive indicator bacterium, L. monocytogenes. Sensitivity to enzymes confirmed the proteinaceous nature of these substances. Neither bacteriophage activity nor fatty acids were detected and the antagonistic activity was not due to residual chloroform. Results did not establish a positive correlation between the bacteriocinogenic profile and toxigenicity in the tested S. aureus strains.Keywords: Cattle, mastitis, toxigenicity, food poisoning, bacteriocin Palavras-chave: bovinos, mastite, toxigenicidade, intoxicação alimentar, bacteriocina RESUMO Avaliou-se a produção de toxina-1 da síndrome do choque tóxico (TSST-1), enterotoxinas e substâncias antagonistas tipo bacteriocina em 95 amostras de Staphylococcus aureus recuperadas de leite bovino in natura (n=31) e de alimentos envolvidos em surto de intoxicação (n=64

Antagonism of Bacteria from Dog Dental Plaque against Human Cariogenic Bacteria

“…The S. aureus overlay was used as a comparison strain in the initial phase of evaluation of the antagonistic activity, as it is used often with the spot-on-the-lawn method. However, as S. aureus is a recognized pathogen for both human and animal health [ 24 ], new studies evaluating the protein nature of isolates from canine dental plaque should be carried out for a possible identification of bioproducts for the treatment of diseases caused by this pathogen.…”

Antagonismo de bactérias ácido-láticas contra Staphylococcus aureus produtor de enterotoxina C em queijo tipo Minas Frescal durante a estocagem

“…As bactérias ácido-láticas (BAL) foram isoladas de soro-fermento de queijarias cadastradas da Canastra e identificadas por análise proteômica adaptada de Freiwald;Sauer (2009), analisadas por Matrix-assisted laser desorption/ ionization -time of flight -mass spectroscopy (MALDI-TOF MS), Bruker Daltonics, modelo UltrafleXtreme. A estirpe produtora da toxina C, foi selecionada, uma vez que a literatura evidencia a incidência em alimentos relacionados em surtos de intoxicação estafilocócica (CARVALHO et al, 2013;SILVA, 2013). Os inóculos bacterianos foram padronizados por enumeração de microrganismos viáveis do cultivo, a 35-37°C após 26 horas, mediante a obtenção da curva de crescimento de cada bactéria.…”