Revealing the genetic traits of the foodborne microbial genus hafnia: Implications for the human gut microbiome.

The bacterial genus Hafnia has recently attracted attention due to its complex metabolic features and host-interaction capabilities, which are associated with health benefits, primarily weight loss. However, significant gaps remain in our understanding of the genomic characteristics of this emerging microbial group. In this study, we utilized all available high-quality genomes of Hafnia alvei and Hafnia paralvei to uncover the broad distribution of Hafnia in human and honeybee guts, as well as in dairy products, by analysing 1068 metagenomic datasets. We then investigated the genetic traits related to Hafnia's production of vitamins and short-chain fatty acids (SCFAs) through a comparative genomics analysis that included all dominant bacterial species in the three environments under study. Our findings underscore the extensive metabolic capabilities of Hafnia, particularly in the production of vitamins such as thiamine (B1), nicotinate (B3), pyridoxine (B6), biotin (B7), folate (B9), cobalamin (B12), and menaquinone (K2). Additionally, Hafnia demonstrated a conserved genetic makeup associated with SCFA production, including acetate, propanoate, and butanoate. These metabolic traits were further confirmed using RNAseq analyses of a newly isolated H. paralvei strain T10. Overall, our study illuminates the ecological distribution and genetic attributes of this bacterial genus, which is of increasing scientific and industrial relevance.

From raw milk cheese to the gut: investigating the colonization strategies of Bifidobacterium mongoliense.

The microbial ecology of raw milk cheeses is determined by bacteria originating from milk and milk-producing animals. Recently, it has been shown that members of the Bifidobacterium mongoliense species may become transmitted along the Parmigiano Reggiano cheese production chain and ultimately may colonize the consumer intestine. However, there is a lack of knowledge regarding the molecular mechanisms that mediate the interaction between B. mongoliense and the human gut. Based on 128 raw milk cheeses collected from different Italian regions, we isolated and characterized 10 B. mongoliense strains. Comparative genomics allowed us to unveil the presence of enzymes required for the degradation of sialylated host-glycans in B. mongoliense, corroborating the appreciable growth on de Man-Rogosa-Sharpe (MRS) medium supplemented with 3'-sialyllactose (3'-SL) or 6'-sialyllactose (6'-SL). The B. mongoliense BMONG18 was chosen, due to its superior ability to utilize 3'-SL and mucin as representative strain, to investigate its behavior when co-inoculated with other bifidobacterial species. Conversely, members of other bifidobacterial species did not appear to benefit from the presence of BMONG18, highlighting a competitive scenario for nutrient acquisition. Transcriptomic data of BMONG18 reveal no significant differences in gene expression when cultivated in a gut simulating medium (GSM), regardless of whether cheese was included or not. Furthermore, BMONG18 was shown to exhibit high adhesion capabilities to HT29-MTX human cells, in line with its colonization ability of a human host.IMPORTANCEFermented foods are nourishments produced through controlled microbial growth that play an essential role in worldwide human nutrition. Research interest in fermented foods has increased since the 80s, driven by growing awareness of their potential health benefits beyond mere nutritional content. Bifidobacterium mongoliense, previously identified throughout the production process of Parmigiano Reggiano cheese, was found to be capable of establishing itself in the intestines of its consumers. Our study underscores molecular mechanisms through which this bifidobacterial species, derived from food, interacts with the host and other gut microbiota members.

Exercise individualized by TRIMPi method reduces arterial stiffness in early onset type 2 diabetic patients: A randomized controlled trial with aerobic interval training.

BACKGROUND: Arterial stiffness (AS) and baroreflex sensitivity (BRS) are subclinical markers of vascular diseases in type 2 diabetes (T2D). We evaluated the effects of aerobic interval training (AIT), with loads prescribed according to individual heart rate and lactate profiling obtained during a baseline treadmill test (TRIMPi method), on AS and BRS in patients with early-onset T2D without cardiovascular complications. POPULATION STUDY AND METHODS: Twenty-two sedentary overweight T2D patients (aged 57±7years) were randomized to 12-weeks open-label of supervised AIT by TRIMPi (n=8) or unsupervised physical activity as per usual care (SOC) (n=11). Following parameters were evaluated (pre- and post-): anthropometrics; six-minute walking test (6MWT); fasting glucose, insulin, HbA1c; Pulse Wave Velocity (PWV) and Augmentation Index (AIxHR75) using radial approach (SphigmoCor System); BRS using Finapress method. RESULTS: Both interventions significantly improved distance walked during 6MWT (AIT 52±21m; SOC 39±24m, p<0.001 for both). PWV significantly improved with AIT (p<0.001) whereas did not vary with SOC (p=0.47). Similar trend was observed for AIxHR75. Resulting percent changes from baseline were significantly better for AIT vs SOC, in both PWV (-15.8±2.1 vs +1.50±3.4%, p<0.001) and AIxHR75 (-28.9±3.2% vs +12.7±2.4%, p<0.001). BRS similarly improved in both groups (p<0.001 for both), as well as body weight, HbA1c and blood pressure. CONCLUSION: In sedentary T2D patients, 12-weeks AIT individualized by TRIMPi method improved AS to a greater extent than usual recommendation on physical activity, whilst exerting comparable effects on exercise capacity, glycemic control and body weight. Further researches are needed to ascertain durability of these effects.