Strategies for the use of bacteriocins in Gram-negative bacteria: relevance in food microbiology

Abstract

Bacteriocins are ribosomally synthesized peptides that have bacteriostatic or bactericidal effects on other bacteria. The use of bacteriocins has emerged as an important strategy to increase food security and to minimize the incidence of foodborne diseases, due to its minimal impact on the nutritional and sensory properties of food products. Gramnegative bacteria are naturally resistant to the action of bacteriocins produced by Gram-positive bacteria, which are widely explored in foods. However, these microorganisms can be sensitized by mild treatments, such as the use of chelating agents, by treatment with plant essential oils or by physical treatments such as heating, freezing or high pressure processing. This sensitization is important in food microbiology, because most pathogens that cause foodborne diseases are Gram-negative bacteria. However, the effectiveness of these treatments is influenced by several factors, such as pH, temperature, the composition of the food and target microbiota. In this review, we comment on the main methods used for the sensitization of Gram-negative bacteria, especially Salmonella, to improve the action of bacteriocins produced by Gram-positive bacteria.

Antibacterial Activity, Cytotoxicity, and the Mechanism of Action of Bacteriocin from <b><i>Bacillus subtilis</i></b> GAS101

“…The variation in antimicrobial activity has been attributed to the selective pressure and the genetic profile of different bacterial strains. It has been proposed that the outer membrane of gram-negative bacteria safeguards its inner membrane, and so higher doses of bacteriocin are required for inhibition of its growth [25]; this is in agreement with our finding.…”

A Bioengineered Nisin Derivative, M21A, in Combination with Food Grade Additives Eradicates Biofilms of Listeria monocytogenes

“…One of the most extensively studied bacteriocins is nisin A, a bactericidal lantibiotic produced by some strains of Lactococcus lactis (Rouse et al, 2012; Campion et al, 2013; Healy et al, 2013). It is a 3.5 kDa peptide consisting of 34 amino acids and is a flexible and elongated amphipathic peptide that has the ability to form pores as well as inhibit cell wall biosynthesis (Breukink et al, 1999; Wiedemann et al, 2001; Prudêncio et al, 2015). This dual action of nisin has meant that despite widespread use in the food industry, there have been few reports of resistance development outside of the laboratory (Field et al, 2010b; Molloy et al, 2012).…”

“…Nisaplin ® is an example of a commercially available food additive, containing 2.5% nisin. It is Generally Regarded As Safe (GRAS) for several applications and has been approved for use in the EU as preservative E234 by Directive 95/2/EC (European Food Safety Authority, 2006) by the U.S. Food and Drug Administration (FDA) (Prudêncio et al, 2015) and by the WHO (Sobrino-López and Martín-Belloso, 2008). …”

“…Enhanced antimicrobial activity has been successfully demonstrated against Gram-positive pathogens when several of these antimicrobials were used in combination with nisin (Phillips, 1999; McEntire et al, 2003; Branen and Davidson, 2004; Bari et al, 2005; Murdock et al, 2007; Norhana et al, 2012). Plant essential oils are another group of additives that have gained increased attention due to a long history of use for their antimicrobial effects and the increased demand for more “natural” food products (Helander et al, 1998; Burt, 2004; Bakkali et al, 2007; Prudêncio et al, 2015). Essential oils are natural, volatile liquids obtained from plant material (Gálvez et al, 2007) that have aromatic qualities (Burt, 2004).…”

Morphological changes in Salmonella Typhimurium caused by the lantibiotic bovicin HC5 in association with EDTA

“…The efficacy of EDTA for sensitizing Gram-negative bacteria to bacteriocins produced by Gram-positive bacteria has been demonstrated extensively on different bacteria, such as Salmonella, Escherichia coli, Enterobacter aerogenes, Citrobacter freudii, Shigella flexneri, Pseudomonas aeruginosa and Arcobacter butzleri (Boziaris and Adams 1999;Elliason and Tatini 1999;Phillips and Duggan 2001;Belfiore et al 2007;Lappe et al 2009;Martin-Visscher et al 2011;Prudêncio et al 2014Prudêncio et al , 2015a. Usually, low concentrations of EDTA (10-20 mM) are sufficient to produce sensitization to the activity of bacteriocins, which are used at different concentrations (100-3200 AU/mL) (Prudêncio et al 2015b).…”