Inhibiting factors produced by lactic acid bacteria. 2. Bacteriocins and other antibacterial substances

Abstract

Summary -Lactic acid bacteria can produce a variety of substances with antibacterial activity which are described in this article. Non-peptide antibacterial substances are distinguished from bacteriocins, which have a proteinaceous active site. Among the former, reuterin produced by Lactobacillus reuteri is a broad spectrum inhibitor active against Gram-positive and Gram-negative bacteria, yeasts, molds and protozoas. It is a glycerol derivative, l3-hydroxypropionaldehyde.Bacteriocins can be produced by most lactic acid bacteria species and their spectrum of activity is generally restricted to organisms taxonomically close to the producer. The biochemical properties of bacteriocins, their structure and nature of their genetic determinants are highly variable. This literature review discusses the similarities and differences existing in this group of substances.

Isolation of bacteriocin-producing lactic acid bacteria from meat and meat products and its spectrum of inhibitory activity

“…Only one was resistant to trypsin (strain CTC 141), while the substance produced by strain CTC 204 lost 75% of its activity after treatment with this enzyme. Some authors differentiate nisin from other lactococcal bacteriocin by the fact that α-chymotrypsin is the only proteolytic enzyme to which nisin is sensitive (14,22). Nevertheless, this property is to be regarded with caution, since other authors have reported that nisin can also be inactivated by other enzymes such as pronase E (15,23), and ficin (5,21).…”

“…On the basis of the definition of bacteriocins of Gram-positive bacteria given by Tagg et al (34) and Klaenhammer (14) and by using the properties observed in bacteriocins from lactic acid bacteria (22), the antibacterial compounds produced by the present strains can be classified as bacteriocins. The pattern of protease sensitivity indicates the singularity of the bacteriocins produced by the isolates and that the strains are different.…”

Antagonistic activity of probiotic organism against Vibrio cholerae and Cryptococcus neoformans

“…of organism has also been reported to be active against the vaginal pathogens. The results also prove the natural medicine correct where buttermilk is used for diarrhea (Piard and Desmazeaud, 1992). Table 2 shows that of the solvents used, chloroform seems to be the best solvent in the extraction of antibacterial compound to prevent the growth of V. cholerae and S. pneumoniae whereas butanol was found to extract antibacterial compound efficiently to inhibit S. dysentriae.…”

“…The inhibitory activity against V. cholerae, S. pneumoniae and S. dysentriae was seen in (Figure 1, 2 and 3 and Table 2) zone of clearance obtained with each organism (Piard and Desmazeaud, 1992;Ogunbanwo et al, 2003).…”

Evaluation of antagonistic activity of milk fermented with kefir grains of different origins

“…This meant that the observed antagonism did not occur as a function of the low pH and, thus, other inhibitor substances might be present in the fermented drink based on the milk and kefir grains, since the thermal treatment employed to obtain the kefir filtrate (50°C for 30 min) did not inactivate the substances such as the bacteriocins and hydrogen peroxide, which were resistant to temperatures of up to 63°C for 30 min (Piard and Desmazeaud 1991). The results orroborated the hypothesis that these chemical compounds present in the kefir grains were associated with antagonistic mechanisms against the pathogens.…”