Evaluation of copper alloys for reducing infection by methicillin resistant Staphylococcus aureus and vancomycin resistant Enterococcus faecium in intensive care unit and in vitro.

BACKGROUND/AIMS: Multi-drug resistant pathogens are increasing among healthcare-associated infections. It is well known that copper and copper alloys have antimicrobial activity. We evaluated the activity of copper against bacteria in a hospital setting in Korea. METHODS: This study was conducted in a laboratory and medical intensive care unit (ICU). Methicillin resistant Staphylococcus aureus (MRSA) and vancomycin resistant Enterococcus faecium (VRE) were inoculated onto copper, copper alloy and stainless steel plates. After 24 hours of incubation, colony-forming units (CFU) were counted in the laboratory. Two similar rooms were chosen in the ICU; one room had copper-containing surface, and the other room contained items with a stainless steel surfaces. Items were sampled weekly for 8 weeks when the rooms were not crowded and when the rooms were busier with healthcare workers or visitors. RESULTS: In vitro time-kill curves showed copper or, a copper alloy yielded a significant reduction in MRSA and VRE CFUs over 15 minutes. Upon exposure to stainless steel plates, CFUs were slowly reduced for 24 hours. In vivo, MRSA CFUs were lower in rooms with copper-containing surfaces compared with controls, both after cleaning and after patients had received visitors (p < 0.05). Analysis of VRE revealed similar results, but VRE CFUs from copper-containing surfaces of drug carts in the ICU did not decrease significantly. CONCLUSION: Copper has antimicrobial activity and appears to reduce the number of multi-drug resistant microorganisms in a hospital environment. This finding suggests the potential of the use of copper fittings, instruments and surfaces in hospital.

Epstein-Barr virus-encoded miR-BART5-5p upregulates PD-L1 through PIAS3/pSTAT3 modulation, worsening clinical outcomes of PD-L1-positive gastric carcinomas.

BACKGROUND: Epstein-Barr virus (EBV) is etiologically associated with ~ 10% of all gastric carcinomas. However, the molecular mechanisms and roles of EBV miRNAs in gastric carcinoma oncogenesis are yet to be elucidated. METHODS: MicroRNA microarray and TaqMan quantitative real-time RT-PCR were conducted. RT-PCR and luciferase reporter assay for PIAS3, western blotting for 20 proteins, immunofluorescence for STAT3, transfection with miRBART5-5p-plasmid, STAT3-plasmid, miRBART5-5p mimic, or PIAS3-siRNA, and in vitro assays for biological effects of PD-L1 were implemented. In situ hybridization for EBV-encoded small RNAs and immunohistochemistry were performed on gastric carcinoma tissues. RESULTS: Transfecting miR-BART5-5p into EBV(-) gastric carcinoma cell lines caused a decrease in PIAS3 3'-UTR reporter activity, PIAS3 downregulation, and subsequent STAT3 activation followed by PIAS3/pSTAT3-dependent PD-L1 upregulation. Interestingly, due to PD-L1 knockdown, apoptosis was increased, while the rate of cell proliferation, invasion capacity, and migration were decreased in miR-BART5-5p-transfected cells. In EBV(+) gastric carcinoma cells, anti-miR-BART5-5p reduced PD-L1 levels through PIAS3/pSTAT3 control. Among 103 patients with EBV-associated gastric carcinomas, overall survival was significantly shortened for those with PD-L1(+) tumors compared to those with PD-L1(-) tumors (P = 0.049). CONCLUSIONS: Our findings imply that miR-BART5-5p directly targets PIAS3 and augments PD-L1 through miR-BART5/PIAS3/pSTAT3/PD-L1 axis control. This contributes to antiapoptosis, tumor cell proliferation, invasion and migration, as well as immune escape, furthering gastric carcinoma progression and worsening the clinical outcome, especially in the PD-L1(+) group of patients with EBV-associated gastric carcinomas. miR-BART5-5p may, therefore, be amenable to PD-1/PD-L1 immune checkpoint inhibitor therapy.

Epstein-Barr virus BARF1-induced NFκB/miR-146a/SMAD4 alterations in stomach cancer cells.

Epstein-Barr virus (EBV)-encoded BamHI-A rightward frame 1 (BARF1) is a putative viral oncogene in EBV-infected stomach cancer. The aim of the present study was to investigate BARF1-induced cellular protein and microRNA alterations. In this study, BARF1-expressing stomach cancer cells showed a high rate of proliferation, high levels of NFκB, and miR-146a upregulation, which was reversed by NFκB knockdown. During BARF1-induced NFκB upregulation, hCSF1 receptor level was unchanged. Knockdown of BARF1 in the naturally EBV-infected YCCEL1 stomach cancer cells suppressed cell proliferation, and downregulated NFκB and miR-146a. SMAD4 was identified as a miR-146a target and was downregulated in BARF1-expressing cells, whereas SMAD4 expression was restored by anti-miR-146a. Knockdown of BARF1 in YCCEL1 cells upregulated SMAD4, and this effect was reversed by miR-146a overexpression. Transfection of BARF1-expressing cells with pCEP4-SMAD4 abolished the cell proliferating effect of BARF1. In stomach cancer tissues, miR-146a was expressed at higher levels, and more frequent NFκB nuclear positivity immunohistochemically, but not of SMAD4 nuclear loss was found in the EBV-positive group compared with the EBV-negative group. In conclusion, EBV-encoded BARF1 promotes cell proliferation in stomach cancer by upregulating NFκB and miR-146a and downregulating SMAD4, thereby contributing to EBV-induced stomach cancer progression.