Minimum information guideline for spectrophotometric and fluorometric methods to assess biofilm formation in microplates

Supplementary data to this article can be found online at https://doi.org/10.1016/j.bioflm.2019.100010.The lack of reproducibility of published studies is one of the major issues facing the scientific community, and the field of biofilm microbiology has been no exception. One effective strategy against this multifaceted problem is the use of minimum information guidelines. This strategy provides a guide for authors and reviewers on the necessary information that a manuscript should include for the experiments in a study to be clearly interpreted and independently reproduced. As a result of several discussions between international groups working in the area of biofilms, we present a guideline for the spectrophotometric and fluorometric assessment of biofilm formation in microplates. This guideline has been divided into 5 main sections, each presenting a comprehensive set of recommendations. The intention of the minimum information guideline is to improve the quality of scientific communication that will augment interlaboratory reproducibility in biofilm microplate assays.This project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska – Curie grant agreement No 722467, as part of the Print-Aid consortium. The information and views set out in this article are those of the authors and do not necessarily reflect the official opinion of the European Union. Neither the European Union institutions and bodies nor any person acting on their behalf may be held responsible for the use which may be made of the information contained therein. This work received additional financial support by: project UID/EQU/00511/2019 - Laboratory for Process Engineering, Environment, Biotechnology and Energy – LEPABE funded by national funds through FCT/MCTES (PIDDAC); Project “LEPABE-2-ECO-INNOVATION” – NORTE-01-0145-FEDER-000005, funded by Norte Portugal Regional Operational Programme (NORTE 2020), under PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF).info:eu-repo/semantics/publishedVersio

Altered gene expression of Staphylococcus aureus upon interaction with human endothelial cells

Staphylococcus aureus is isolated from a substantial number of patients with infective endocarditis who are not known to have predisposing heart abnormalities. It has been suggested that the infection is initiated by the direct binding of S. aureus to human vascular endothelium. To determine the mutual response of the endothelial cells and the bacteria, we studied the interaction between S. aureus and human vascular endothelium. Scanning electron microscopic analyses showed that binding of S. aureus to human umbilical vein endothelial cells (HUVEC) mainly occurred via thread-like protrusions extending from the cell surface. Bound bacteria appeared to be internalized via retraction of the protrusions into newly formed invaginations of the endothelial cell surface. The growth phase of S. aureus had a major impact on the interaction with HUVEC. Logarithmically growing bacteria showed increased binding to, and were more readily internalized by, HUVEC compared to stationary-phase bacteria. To assess the bacterial response to the cellular environments an expression library of S. aureus was used to identify genes whose expression was induced after 4 h of exposure to HUVEC. The identified genes could be divided into different categories based on the functions of the encoded proteins (transport, catabolism, biosynthesis, and DNA repair). Further analyses of five of the S. aureus transposon clones showed that HUVEC as well as human serum are stimuli for triggering gene expression in S. aureus

Medical-grade honey enriched with antimicrobial peptides has enhanced activity against antibiotic-resistant pathogens

Honey has potent activity against both antibiotic-sensitive and -resistant bacteria, and is an interesting agent for topical antimicrobial application to wounds. As honey is diluted by wound exudate, rapid bactericidal activity up to high dilution is a prerequisite for its successful application. We investigated the kinetics of the killing of antibiotic-resistant bacteria by RS honey, the source for the production of Revamil® medical-grade honey, and we aimed to enhance the rapid bactericidal activity of RS honey by enrichment with its endogenous compounds or the addition of antimicrobial peptides (AMPs). RS honey killed antibiotic-resistant isolates of Pseudomonas aeruginosa, Staphylococcus epidermidis, Enterococcus faecium, and Burkholderia cepacia within 2 h, but lacked such rapid activity against methicillin-resistant S. aureus (MRSA) and extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli. It was not feasible to enhance the rapid activity of RS honey by enrichment with endogenous compounds, but RS honey enriched with 75 μM of the synthetic peptide Bactericidal Peptide 2 (BP2) showed rapid bactericidal activity against all species tested, including MRSA and ESBL E. coli, at up to 10–20-fold dilution. RS honey enriched with BP2 rapidly killed all bacteria tested and had a broader spectrum of bactericidal activity than either BP2 or honey alone

Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.

Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability

Accuracy of carbohydrate-deficient transferrin in the detection of excessive alcohol consumption: A systematic review

Aims: Excessive alcohol consumption is a common problem in society and medical practice. There is a need for a diagnostic tool with both high sensitivity and specificity for the detection of excessive alcohol consumption in unselected medical populations. Therefore, we evaluated the diagnostic accuracy of carbohydrate-deficient transferrin (CDT) in the detection of excessive alcohol consumption. Methods: Computerised literature searches in Medline, Embase and Current Contents databases (01/1966-06/2003) and reference checking. Articles on the detection of excessive alcohol consumption reporting CDT levels and self-reported alcohol consumption as a reference test were selected (n = 101). Studies concerning treatment, relapse detection and traffic offenders were excluded. Quality assessment and data-extraction was done by two reviewers independently. Only studies scoring positive on core validity criteria by Lijmer were eligible for quantitative analysis (n = 29). Results: Only two CDT-assays (CDTect and CDTriTIA) were evaluated in more than two high validity studies fulfilling the criteria for inclusion in the statistical analysis. Sensitivity of CDTect (14 data points) ranged from 20 to 85%, whereas specificity ranged from 77 to 95%. A summary ROC curve was computed for CDTect. Sensitivity of CDTTriTIA (4 data points) ranged from 10 to 67%, and specificity ranged from 90 to 100%. No summary measure could be computed for CDTTriTIA. The heterogeneity of results could not be explained clinically. Conclusions: The validity of CDT as a diagnostic tool is still questionable. If the higher values for sensitivity that some studies report can be confirmed by others it is a useful diagnostic tool in unselected populations. However, more methodologically sound, comparable studies need to be performed before firm conclusions can be draw

Minimum information guideline for spectrophotometric and fluorometric methods to assess biofilm formation in microplates

The lack of reproducibility of published studies is one of the major issues facing the scientific community, and the field of biofilm microbiology has been no exception. One effective strategy against this multifaceted problem is the use of minimum information guidelines. This strategy provides a guide for authors and reviewers on the necessary information that a manuscript should include for the experiments in a study to be clearly interpreted and independently reproduced. As a result of several discussions between international groups working in the area of biofilms, we present a guideline for the spectrophotometric and fluorometric assessment of biofilm formation in microplates. This guideline has been divided into 5 main sections, each presenting a comprehensive set of recommendations. The intention of the minimum information guideline is to improve the quality of scientific communication that will augment interlaboratory reproducibility in biofilm microplate assays.Peer reviewe