National monitoring study on microbial contamination of food-contact surfaces in hospital kitchens in Poland

Introduction and objective: The risk of food-borne infections in hospitalized patients with compromised immune systems is much higher and can also lead to more serious health consequences than among other population groups. Therefore, food hygiene within the hospital setting, should be handled in an appropriate manner. In 2008, there were 732 hospitals in Poland. It was estimated that 7.2 million hospitalized patients, with an average hospital stay of 5.9 days, benefited from hospital meals. On average, nearly half of the hospitals (ranging from 30%-50%, depending on the province) outsourced the preparation and delivery of meals to external service providers. The objective of this study was to survey the bacteriological contamination of selected food production and processing areas in hospital kitchens in Poland. Materials and methods: The nationwide microbiological examination of food contact surfaces was performed in 10% of randomly selected hospital kitchens in all 16 provinces in Poland. A total of 3,277 samples were scientifically examined for hygiene indicator micro-organisms; namely, for Total Viable Count (TVC), Enterobacteriaceae count and coliforms, as well as for the presence of coagulase-positive staphylococci. The environmental samples were collected and examined according to European and Polish standards. All analyses were performed using Statistica version 6 software. Results: The results revealed that food hygiene within the test sample was poor. Of the total samples taken for testing, 25.5% failed. The most common failures were related to excess TVC in swabs. Conclusion: Testing shows that there is a need to improve the standard of hygiene in food handling areas of Polish hospitals

Gain-of-function genetic screens in human cells identify SLC transporters overcoming environmental nutrient restrictions.

Solute carrier (SLC) transporters control fluxes of nutrients and metabolites across membranes and thereby represent a critical interface between the microenvironment and cellular and subcellular metabolism. Because of substantial functional overlap, the interplay and relative contributions of SLCs in response to environmental stresses remain poorly elucidated. To infer functional relationships between SLCs and metabolites, we developed a strategy to identify SLCs able to sustain cell viability and proliferation under growth-limiting concentrations of essential nutrients. One-by-one depletion of 13 amino acids required for cell proliferation enabled gain-of-function genetic screens using a SLC-focused CRISPR/Cas9-based transcriptional activation approach to uncover transporters relieving cells from growth-limiting metabolic bottlenecks. Among the transporters identified, we characterized the cationic amino acid transporter SLC7A3 as a gene that, when up-regulated, overcame low availability of arginine and lysine by increasing their uptake, whereas SLC7A5 was able to sustain cellular fitness upon deprivation of several neutral amino acids. Moreover, we identified metabolic compensation mediated by the glutamate/aspartate transporters SLC1A2 and SLC1A3 under glutamine-limiting conditions. Overall, this gain-of-function approach using human cells uncovered functional transporter-nutrient relationships and revealed that transport activity up-regulation may be sufficient to overcome environmental metabolic restrictions