Gut microbiota, body weight and histopathological examinations in experimental infection by methicillin-resistant Staphylococcus aureus: antibiotic versus bacteriocin.

Bacteriocins have been steadily reported as potential agents that may contribute, in different ways, to overcome antimicrobial drug resistance. Here, holoxenic NMRI-F mice microbiota, their body weight recovery and histopathological alterations of organs like colon, spleen and liver were examined in mice intraperitoneally infected with 108 cfu of a clinical methicillin-resistant Staphylococcus aureus (MRSA-1), and treated with enterocin DD14 alone (165 mg/kg), erythromycin alone (100 mg/kg) or their combination. Animals that received both antimicrobials presented a better body weight recovery than other groups. Less pronounced histopathological alterations were observed in mice MRSA-infected and treated with bacteriocin than in those MRSA-infected but untreated or MRSA-infected and treated with erythromycin. Noteworthy, these alterations were absent when mice were treated with MRSA-infected and treated with both antibacterial agents. Furthermore, the genus richness was significantly lower in mice infected and treated with erythromycin, compared to mice infected and treated with both antimicrobials. The beta-diversity analysis showed that non-infected mice and those infected and treated with both antimicrobials, stand apart from the other groups as supported in a NMDS model. This in vivo study shows the relevance of bacteriocin, or bacteriocin-antibiotic formulation in protecting colonic, liver and spleen soft tissues and controlling the mouse gut microbiota, following MRSA infection.

In vitro and in vivo cholesterol lowering ability of Lactobacillus pentosus KF923750.

Lactobacillus pentosus KF923750 was characterised for probiotic related properties and then characterised for cholesterol uptake in vitro as well as in vivo using rabbits fed a high-cholesterol diet. The survival percentage of L. pentosus KF923750 was 100% at pH 3, 52.18% at pH 2 and 36.21% at pH 2 plus pepsin. Similarly, this strain appeared resistant to bile (0.1% [98.42%], 0.3% [88.52%], 0.5% [75.60%] and 1% [71.15%]), after 4 h exposure. Moreover, L. pentosus KF923750 controlled growth of Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923 through the production of a bacteriocin-like inhibitory substance and anti-adhesive capabilities. L. pentosus KF923750 was non-cytotoxic to eukaryotic cells but sensitive to some antibiotics. Compared with rabbits fed a high-cholesterol diet but without L. pentosus KF923750 supplementation, the plasma total cholesterol, low-density lipoprotein cholesterol and triglycerides levels were significantly decreased in L. pentosus KF923750-fed rabbits by 11.54, 16.00 and 18.00%, respectively, with no significant change in high-density lipoprotein cholesterol levels. The histological sections of livers revealed lesions in all the rabbits that were fed a high-cholesterol diet, but these were less pronounced in rabbits ingesting L. pentosus KF923750. This study highlights the potential of lactobacilli, such as L. pentosus KF923750, in the treatment or prevention of hypercholesterolemia.