Dados do Trabalho

Título

Screening for bacteriocin and virulence genes in the DNA of Enterococcus faecium isolated from Brazilian artisanal cheesemaking environment

Introdução

Lactic acid bacteria (LAB) have been subject for evaluation associated to their biotechnological and beneficial properties applicated in fermented food products, including different dairy products. During cheese production, antimicrobial metabolites, including bacteriocins are produced by LABs and plays essential role in competing with other microorganisms from the dairy environment contributing to biopreservation of dairy products.
In current study we screened for safe bacteriocin-producing strains, with focus on presence for virulence and bacteriocinogenic genes reaching on an Enterococcus faecium strain isolated Brazilian artisanal cheesemaking environment.

Material e Métodos

Swabs were collected from the surfaces in an artisanal cheese production facility at local producer (region of São Paulo). Based on the performed screening for bacteriocinogenic LAB with activity against Listeria monocytogenes ATCC7644, and after 16S rRNA sequencing, Enterococcus faecium ST02JL was selected for further studied. The E. faecium ST02JL was grown in MRS broth for 24h at 37ºC and DNA extracted by Quick-DNA Fungal/Bacterial Miniprep Kit. The obtained DNA was screened for caring bacteriocin (nisin, pediocin PA-1, different enterocins - A, B, P, 50, lactococcin, lacticin and garvicin) and virulence genes (vancomycin resistance, insertion element (IS16), adhesin of collagen protein (ace), endocarditis antigen (efaA), enterococcal surface protein (esp), aggregation substance (asa1), hyaluronidase (hyl), histidine decarboxylase (hdc), tyrosine decarboxylase (tdc), ornithine decarboxylase (odc), cytolysin (cylA) and gelatinase (gelE)).

Resultados e Discussão

Screening of bacteriocin production genes showed that entA and entP were carried by E. faecium ST02JL. Moreover, gene encoding for production of pediocin PA-1 was also recorded. The enterocins identified in our strain belong to class II, “pediocin-like” bacteriocins, with a general mechanism of action that causes cell lysis. Moreover, E. faecium ST02JL can be considered as safe strain since none of the mentioned virulence genes were recorded.

Conclusão

Lactic acid bacteria and their bacteriocins if well characterized as safe, can be used as biopreservatives in products or production surfaces achieving current trends in society, industry, and academia, which seek to replace traditional preservation methods that employ common chemical agents.