A Lactobacilli diet that confers MRSA resistance causes amino acid depletion and increased antioxidant levels in the C. elegans host

Abstract

Probiotic bacteria are increasingly popular as dietary supplements and have the potential as alternatives to traditional antibiotics. We have recently shown that pretreatment with Lactobacillus spp. Lb21 increases the life span of C. elegans and results in resistance toward pathogenic methicillin-resistant Staphylococcus aureus (MRSA). The Lb21-mediated MRSA resistance is dependent on the DBL-1 ligand of the TGF-β signaling pathway. However, the underlying changes at the metabolite level are not understood which limits the application of probiotic bacteria as timely alternatives to traditional antibiotics. In this study, we have performed untargeted nuclear magnetic resonance-based metabolic profiling. We report the metabolomes of Lactobacillus spp. Lb21 and control E. coli OP50 bacteria as well as the nematode-host metabolomes after feeding with these diets. We identify 48 metabolites in the bacteria samples and 51 metabolites in the nematode samples and 63 across all samples. Compared to the control diet, the Lactobacilli pretreatment significantly alters the metabolic profile of the worms. Through sparse Partial Least Squares discriminant analyses, we identify the 20 most important metabolites distinguishing probiotics from the regular OP50 food and worms fed the two different bacterial diets, respectively. Among the changed metabolites, we find lower levels of essential amino acids as well as increased levels of the antioxidants, ascorbate, and glutathione. Since the probiotic diet offers significant protection against MRSA, these metabolites could provide novel ways of combatting MRSA infections.

Usage of Cultured Human Fecal Microbiota for Colonization of Caenorhabditis elegans to Study Host–Microbe Interaction

“…The metabolites may hold an important key to understanding how the microbiota can influence host physiology and health. We have recently characterized the metabolome of probiotic Lactobacillus bacteria compared to the traditional OP50 diet and found significant differences [18]. Interestingly, when the metabolomes of the bacterial diets are compared to the metabolomes of C. elegans fed a batch of the same bacteria, we find that these are not identical.…”

“…Furthermore, metabolic profiling revealed significantly different metabolomes of the probiotic Lactobacillus spp. and OP50 which may also contribute to the beneficial effects [18]. There is a strong correlation between stress resistance and lifespan in C. elegans [19] and there is increasing evidence suggesting that the microbiota may affect aging [20].…”

Geroprotective potential of microbiome modulators in the Caenorhabditis elegans model

“…Untargeted nuclear magnetic resonance-based metabolomics revealed that geroprotective effects of Lactobacillus spp. Lb21 were associated with increases or changes in metabolites related to energy metabolism and oxidative stress/osmoregulation, suggesting the importance of metabolic flux in regulating lifespan and health [ 109 ]. Furthermore, high accumulation of Lactobacillus delbrueckii subsp.…”