Microbiological Study of Kefir Grains. Isolation and Identification of High Activity Bacteriocin Producing Strains

A new class of antimicrobial molecules derived from kefir, effective against Pseudomonas aeruginosa and methicillin resistant Staphylococcus aureus (MRSA) strains

“…The present work has demonstrated that the antibacterial activity of kefir against MRSA and P. aeruginosa strains is strongly associated with the source and the composition of the kefir grains in terms of the microorganisms present, since the antimicrobial-producing and the antimicrobial-nonproducing grains have distinctly different microbiota. Despite the presence of 19 different bacterial families in the antimicrobial nonfunctional grains, 94.43% of all bacterial species encountered belonged to the Lactobacilaceae family, which according to the scientific literature has a high number of bacterial species able to produce antimicrobial peptides such as bacteriocins 7,14,27 . In contrast, only nine bacterial families were encountered in the antimicrobial-producing grains, the Lactobacilacea family being responsible for 56% of them.…”

“…In recent times, these variations are even greater since fruit juices and molasses have been used as substrates to prepare kefir 12 , 13 . Accordingly, several groups have decided to isolate bacterial strains from the grains and study their ability to produce antimicrobial molecules separately from the whole microbiome 7 , 14 . The results obtained from those studies demonstrated that several isolates were able to produce bacteriocins, which are antimicrobial molecules genetically coded, synthesized through the ribosomal machinery and classified according to their size, structure and resistance to heat 7 , 15 , 16 .…”

Bioactive Peptides used by Bacteria in the Concur-Rence for the Ecological Niche: General Classification and Mode of Action (Overview)

“…Class III Class III bacteriocins includes large thermo-labile peptides, such as helveticin J, acidophilicin A and lacticins A and B. Although some of them are discovered by decades (in the case of the bacteriocins produced by Clostridium acetobutilicum and Lactobacillus paracasei (130,131,132)), only limited progress have been done till now in their precise characterization. However researches have been made on some of them.…”

Biotecnología del kéfir: una revisión sobre las aplicaciones y sus perspectivas futuras

“…Se ha encontrado que la familia Lactobacillacea es en parte responsable de la actividad antimicrobiana (Marques et al, 2020) cuyo efecto se debe a la producción de bacteriocinas (Atanassova et al, 1999), además de la inhibición competitiva de la adhesión de enteropatógenos a las células epiteliales (Santos et al, 2003). Se sugiere que el efecto bactericida, al igual que el fungicida del kéfir, en conjunto con lo antes mencionado, se debe a la presencia de ácidos orgánicos, etanol y diacetilo (Gamba et al, 2016;Kim et al, 2016;Sirirat & Jelena, 2010).…”