RESUMO
Carnobacterium maltaromaticum is a species of lactic acid bacteria (LAB) that has been isolated from various natural environments. It is well-known for producing a diverse spectrum of bacteriocins with potential biotechnological applications. In the present study, a new psychrotolerant strain of C. maltaromaticum CM22 is reported, isolated from a salmon gut sample and producing a variant of the bacteriocin piscicolin 126 that has been named piscicolin CM22. After identification by 16S rRNA gene, this strain has been genomically characterized by sequencing and assembling its complete genome. Moreover, its bacteriocin was purified and characterized. In vitro tests demonstrated that both the strain and its bacteriocin possess antimicrobial activity against several Gram-positive bacteria of interest in human and animal health, such as Listeria monocytogenes, Clostridium perfringens, or Enterococcus faecalis. However, this bacteriocin did not produce any antimicrobial effect on Gram-negative species. The study of its genome showed the genetic structure of the gene cluster that encodes the bacteriocin, showing a high degree of homology to the gene cluster of piscicolin 126 described in other C. maltaromaticum. Although more studies are necessary concerning its functional properties, this new psychrotolerant strain C. maltaromaticum CM22 and its bacteriocin could be considered an interesting candidate with potential application in agri-food industry.
RESUMO
The use of phytogenic extracts is considered a sustainable strategy for the prevention of fish diseases, including Alliaceae as a potential option due to their variety of bioactive compounds. In this study, we analyzed the antibacterial and antiparasitic potential of propyl-propane-thiosulfinate (PTS) and propyl-propane-thiosulfonate (PTSO) from onions. The in vitro activity against Pseudomonas anguilliseptica, Tenacibaculum maritimum, and Photobacterium damselae of both compounds was tested. In addition, the viability of Sparicotyle chrysophrii larvae was evaluated. Moreover, a diet that consisted of a blend of PTS/PTSO (ALLIUM) was used. A total of 90 gilthead sea bream juveniles were tested against P. damselae subsp. Piscicida after 12 weeks of dietary administration. Furthermore, 150 fish with a rate of 10-15 parasites/fish were fed for 21 days and the number of gill parasites was recorded. All strains were sensitive to both compounds. PTSO showed the highest inhibitory effect against all target strains, while PTS showed higher effectiveness against S. chrysophrii. Fish from ALLIUM group presented the highest probability of survival, increasing up to 91.1%, whereas in the control group, the probability of survival was 66.7%. The number of parasites in the gilthead sea bream decreased in the ALLIUM group over time. These results suggest the inclusion of PTS and PTSO in feed as a natural strategy to prevent antibacterial and antiparasitic fish diseases.
