Intracellular Staphylococcus aureus has been implicated in the establishment of chronic infections. It is therefore imperative to understand by what means S. aureus is able to survive within cells. Here we use two expression systems with a fluorescent readout to assay alpha-toxin expression and function within phagolysosomes of infected upper-airway epithelial cells: avirulent Staphylococcus carnosus TM300 and phenotypically alpha-toxin-negative S. aureus laboratory strains. Data from CFU recovery assays suggest that the presence of alpha-toxin is not beneficial for the intracellular survival of recombinant Staphylococcus strains. This finding was corroborated by immunofluorescence studies: whereas S. carnosus and S. aureus are able to deliver S. aureus alpha-toxin to lumina of host cell phagolysosomes, the membrane integrity of these organelles was not affected. Alpha-toxin-expressing strains were detected exclusively within lysosome-associated membrane protein 1 (LAMP1)-yellow fluorescent protein (YFP)-positive vesicles. Measurements of intraphagosomal pH illustrated that all infected phagolysosomes acidified regardless of alpha-toxin expression. In contrast, S. aureus expressing Listeria monocytogenes listeriolysin O leads to the breakdown of the phagolysosomal membrane, as indicated by staphylococci that are not associated with LAMP1-YFP-decorated vesicles and that do not reside within an acidic cellular environment. Thus, our results suggest that staphylococcal alpha-toxin is not sufficient to mediate phagolysosomal escape in upper-airway epithelial cells.

We aim to present an overview of the possible influence of drinking water in general and mineral water in particular in improving glycemic parameters in persons with or without type 2 diabetes. We performed a literature search that produced 15 randomized controlled trials (RCTs) on this topic with mainly small sample sizes. We also discuss relevant observational and animal studies as well as the effects of important supplements in mineral water such as hydrogencarbonate and magnesium. There is low evidence for the positive effects of water or mineral water in improving glycemic parameters in diabetic and non-diabetic persons, and the results are heterogenous, making it difficult to reach an unequivocal conclusion. Meta-analyses of prospective cohort studies and other observational studies, studies with animal models and interventional studies using hydrogencarbonate and magnesium supplements suggest a probable positive effect of drinking water and mineral water in particular on glycemic parameters, supporting the positive results found in some of the RCTs, especially those substituting diet beverages or caloric beverages with water, or those using bicarbonate and magnesium-rich water. Regarding the high prevalence, the associated suffering and the resulting health expenditures of type 2 diabetes, it is imperative to conduct larger and more rigorous trials to answer the question whether drinking water or mineral water can improve glycemic parameters in diabetic and non-diabetic persons.

We aim to present an overview of the possible influence of drinking water in general and mineral water in particular in improving glycemic parameters in persons with or without type 2 diabetes. We performed a literature search that produced 15 randomized controlled trials (RCTs) on this topic with mainly small sample sizes. We also discuss relevant observational and animal studies as well as the effects of important supplements in mineral water such as hydrogencarbonate and magnesium. There is low evidence for the positive effects of water or mineral water in improving glycemic parameters in diabetic and non-diabetic persons, and the results are heterogenous, making it difficult to reach an unequivocal conclusion. Meta-analyses of prospective cohort studies and other observational studies, studies with animal models and interventional studies using hydrogencarbonate and magnesium supplements suggest a probable positive effect of drinking water and mineral water in particular on glycemic parameters, supporting the positive results found in some of the RCTs, especially those substituting diet beverages or caloric beverages with water, or those using bicarbonate and magnesium-rich water. Regarding the high prevalence, the associated suffering and the resulting health expenditures of type 2 diabetes, it is imperative to conduct larger and more rigorous trials to answer the question whether drinking water or mineral water can improve glycemic parameters in diabetic and non-diabetic persons.People who don't drink sugar sweetened beverages tend to have higher quality diets and do not compensate for sugar or energy deficits by consuming more sugary foods [7].A nutrition survey examining the relationship between the quantity of water taken in and HbA1c in 1035 participants calculated that an increase of 240 mL in daily water intake reduces the risk of elevated HbAc1 >5.5% by 22% in men but not in women [8].A review of 134 randomized controlled trials (RCTs), where water consumption was increased right before or during a meal, showed heterogenic effects on energy intake, energy expenditure, fat oxidation and weight change [9].Moreover, mineral nutrients such as bicarbonate [10] and magnesium [11], in particular, are thought to affect glucose metabolism. An increased dietary acid load is associated with the development of insulin resistance [12], while a pre-existing diabetes favors acidosis, which, in turn, leads to increased insulin resistance [13].Drinking recommendations are less common and detailed than food recommendations [3,14], and there is little scientific evidence, and, to our knowledge, no review of RCTs on drinking water and its influence on glycemic parameters, respectively type 2 diabetes.This review aims to explore to what extent drinking water with low or high mineralization for at least four weeks influences glycemic parameters in healthy or type 2 diabetes participants in daily life situations as compared with other drinks. The results of the RCTs found in the literature search will be discussed alongsid...

To address the question whether there is evidence that drinking water in general or mineral water in particular is effective in preventing diabetes; we performed a literature search of randomized controlled trials (PubMed). The search resulted in very few trials (N = 9) investigating this topic: one trial investigates the effect of increasing water consumption on glycemic control in diabetic patients; two trials investigate the effect of drinking water with a meal in diabetic patients; while six trials compare the effect of mineral rich water with that of low mineralized water on glucose metabolism in healthy subjects. There is evidence that increasing water consumption can improve glucose metabolism and randomized controlled trials with mineral water suggest that waters containing relevant amounts of magnesium can exert an additional effect. The role of bicarbonate; which is present in all the mineral waters used in the trials; will be discussed. Future research needs to investigate the effect of mineral water in prediabetic individuals or individuals with impaired glycemic control.

No abstract