SummaryAs an important facet of host-pathogen interaction, Staphylococcus aureus has the ability to adhere to human extracellular matrix (

UVC-treated PLTs stored for 5 days showed marginal changes in PLT metabolism and activation in vitro and were associated with a degree of reduction in recovery and survival similar to other pathogen inactivation systems that are licensed and in use.

We describe a novel FP mutation that may affect 1:500 European blood donors and causes rapid loss of potassium from stored RBCs. This finding has implications for neonates and infants receiving large-volume RBC transfusions. Genomic screening of donors could be used to identify donors with this mutation and potentially improve the quality and safety of donor units.

We conclude that storage of platelets in 70% Composol vs 100% plasma does not increase the rate of platelet apoptosis. Our data agree with other studies suggesting that platelet apoptosis is sequential to high levels of activation, but share a significant degree of overlap.

What This Article Tells Us That Is New • In a porcine model, red blood cell washing along with an inosine rejuvenation solution restored red cell energy stores, reduced inflammatory responses, and reduced transfusionassociated organ injury in swine in 14-day-old stored blood

The maintenance of platelet function in vitro during extended storage of PCs in platelet additive solutions is dependent on the combination of type of additive solution and type of platelet storage bag. For all bag types studied, storage in PASII resulted in poorer platelet function in vitro.

A model system mimicking Staphylococcus aureus bacteremia was developed by growth in serum under microaerobic conditions. Eight genes induced by growth in serum were identified, including an antimicrobial peptide biosynthesis locus, amino acid biosynthetic loci, and genes encoding putative surface proteins. Nine independent insertions were found in the major lysine biosynthesis operon, which encodes eight genes, is repressed by lysine in vitro, and is expressed in vivo.Staphylococcus aureus is a highly adaptable human pathogen in which differential gene expression is known to occur in response to environmental conditions, both in vitro (1,8,17) and in vivo (9). Previous reports have demonstrated that in vitro conditions can be used to mimic those in vivo, for example, the use of cell culture extracts and mammalian cell cultures (13,17). In this study, a model system of growth in serum has been established and characterized.Growth of S. aureus in serum. S. aureus 8325-4 (12) was grown in both brain heart infusion (BHI) broth and pig serum (Sigma) under aerobic and microaerobic conditions (8% O 2 -5% CO 2 -87% N 2 ). Microaerobic growth in serum resulted in a higher growth rate and yield than did aerobic growth (optical densities at 600 nm [OD 600 ], 6.1 and 4.2, respectively; 7 h) (results not shown). Growth in human serum produced trends identical to those seen in pig serum (results not shown). BHI gave a higher growth yield than did serum and, in contrast to the results for serum, in BHI aerobic growth was found to be optimal (OD 600, 7.9 [microaerobic] and 10.2 [aerobic]; 7 h) (results not shown).Identification of serum-expressed genes (seg). Genes specifically induced in serum versus BHI were identified by replica plating Tn917 insertion libraries (19) on serum agar and BHI agar, both containing 5-bromo-4-chloro-3-indolyl-␤-D-galactopyranoside (X-Gal) (80 g/ml). Following incubation at 37°C (microaerobic for serum and aerobic for BHI), colonies that were blue on serum and white on BHI were selected and rescreened. Twenty-three clones with increased LacZ activity on serum were selected and further characterized. No growth defects on serum or BHI were observed for any of the clones.

Background There is renewed interest in the use of whole blood (WB) for the resuscitation of trauma patients. Platelet function in stored WB compared to platelet concentrates is not well established and was assessed in vitro in this study. Methods Leucocyte‐depleted cold‐stored WB (CS‐WB) was prepared using a Terumo WB‐SP Imuflex kit and held at 2–6°C alongside: (A) UK standard pooled platelets stored at 20–24°C (RT‐PLTS), (B) pooled platelets stored at 2–6°C (CS‐PLTS), and (C) platelet‐rich plasma produced using the Terumo kit (CS‐PRP), for 21 days. A series of in vitro assays were assessed platelet function. Results Platelet count was retained to 57 ± 14% of starting number at day 21 in CS‐WB. Over time, CS‐WB platelets become more activated, with increased CD62P expression (day 1: 7 ± 3.7% vs. day 21: 59 ± 17.1%) and annexin V binding (day 1: 2 ± 0.2% vs. day 21: 21 ± 15.1%). For comparison, 18.6 ± 6% of platelets in RT‐PLTS demonstrated CD62P expression at day 7, whereas annexin V binding in RT‐PLTS at day 7 was 2.6 ± 0.5%. Over storage, aggregatory response to agonists decreased in all arms. Functional platelet microparticles increased steadily in CS‐WB throughout storage. Conclusion During storage, platelet count reduced in CS‐WB, whereas CD62P expression and annexin V binding increased. This was accompanied by a reduced aggregatory response, although compared to 7‐day‐old RT‐PLTS, CS‐WB maintained a maximal response to agonists for longer, suggesting that the shelf life for CS‐WB can be considered for up to 21 days.