Antibiotic resistance has been cited by the World Health Organisation (WHO) as one of the greatest threats to public health. Mitigating the spread of antibiotic resistance requires a multipronged ...approach with possible interventions including faster diagnostic testing and enhanced antibiotic stewardship. This study employs a low-cost diagnostic sensor test to rapidly pinpoint the correct antibiotic for treatment of infection. The sensor comprises a screen-printed gold electrode, modified with an antibiotic-seeded hydrogel to monitor bacterial growth. Electrochemical growth profiles of the common microorganism,
(
) (ATCC 25922) were measured in the presence and absence of the antibiotic streptomycin. Results show a clear distinction between the
growth profiles depending on whether streptomycin is present, in a timeframe of ≈2.5 h (
< 0.05), significantly quicker than the current gold standard of culture-based antimicrobial susceptibility testing. These results demonstrate a clear pathway to a low cost, phenotypic and reproducible antibiotic susceptibility testing technology for the rapid detection of
within clinically relevant concentration ranges for conditions such as urinary tract infections.
Accurate and rapid diagnostic tests are critical to reducing the impact of SARS-CoV-2. This study presents early, but promising measurements of SARS-CoV-2 using the ACE2 enzyme as the recognition ...element to achieve clinically relevant detection. The test provides a scalable route to sensitive, specific, rapid and low cost mass testing.
SARS-CoV-2 diagnostic practices broadly involve either quantitative polymerase chain reaction (qPCR)-based nucleic amplification of viral sequences or antigen-based tests such as lateral flow assays ...(LFAs). Reverse transcriptase-qPCR can detect viral RNA and is the gold standard for sensitivity. However, the technique is time-consuming and requires expensive laboratory infrastructure and trained staff. LFAs are lower in cost and near real time, and because they are antigen-based, they have the potential to provide a more accurate indication of a disease state. However, LFAs are reported to have low real-world sensitivity and in most cases are only qualitative. Here, an antigen-based electrochemical aptamer sensor is presented, which has the potential to address some of these shortfalls. An aptamer, raised to the SARS-CoV-2 spike protein, was immobilized on a low-cost gold-coated polyester substrate adapted from the blood glucose testing industry. Clinically relevant detection levels for SARS-CoV-2 are achieved in a simple, label-free measurement format using sample incubation times as short as 15 min on nasopharyngeal swab samples. This assay can readily be optimized for mass manufacture and is compatible with a low-cost meter.
Display omitted
•Isolation and structure elucidation of sponge natural products.•Nucleosides from marine invertebrates.•Unusual isoguanosine derivatives.
After a chemical screening of subtidal ...sponges from the Northeastern Atlantic, Clathria (Microciona) strepsitoxa (Poecilosclerida: Microcionidae) was selected for deeper investigation. This first chemical study led to the identification of two new 8-oxoisoguanosine derivatives. The structure elucidation was performed after extensive analyses of spectroscopic (1D and 2D NMR) and HR-ESIMS data and no significant antimicrobial or cytotoxic activity was detected.
Display omitted
•3 New suberitanes derivatives were isolated from the Antarctic sponge Phorbas areolatus.•They represent new examples of sesterterpenoids of the suberitane families found in Antarctic ...sponges.•Two of them exhibit moderate cytotoxicity on tumoral cell lines.•This finding rules out suberitanes as chemotaxonomic markers of the genus Suberites.
Following ecological and chemical screenings, the Antarctic sponge Phorbas areolatus was chemically investigated for the first time. Three new suberitane derivatives named isosuberitenone B, 19-episuberitenone B, and isoxaspirosuberitenone were identified together with the known compounds suberitenones A and B, and oxaspirosuberitenone after a thorough inspection of their NMR data. These compounds were found to exhibit moderate cytotoxic activity and their presence in this sponge rules out their use as a chemotaxonomic marker for Suberites sponges.
Despite bacterial biofilms representing a common form of infection, notably on medical devices post implantation, their detection and characterisation with existing methods is not sufficient to ...inform clinicians about biofilm presence or treatment response in affected patients. This study reports the development and use of a combined hyperspectral imaging (HSI) and electrochemical platform to monitor biofilm formation optically and electrochemically. Firstly, production of pyocyanin, a common pigmented and redox active secondary metabolite produced by P. aeruginosa , is monitored by combined HSI and square-wave voltammetry. Secondly, P. aeruginosa biofilm formation is characterised directly using electrochemical impedance spectroscopy. This suite of optical and electrochemical measurements allows for combined monitoring of secondary metabolite/virulence factor production along with direct monitoring of biofilm formation on the sensor surface. Crucially, the easy to deploy and low-cost nature of the selected sensing technologies means the approach can be developed for enhanced study of biofilms and/or at the point of care.
The opportunistic pathogen,
Pseudomonas aeruginosa
, is infamous for its ability to rapidly form biofilms (<24 h) in inhospitable environments and the development of antimicrobial resistance (AMR). ...It has been seen to have resistance to nearly all known antibiotics, including last-line antibiotics colistin and carbapenems. AMR is currently considered one of the biggest threats to human health, causing 700,000 deaths annually, expected to rise to 10 million deaths per year by 2050.
P. aeruginosa
, alongside other opportunistic pathogens, has been implicated in infections following various surgical procedures. Such infections compromise patient recovery and, when a medical implant is present a biofilm can develop that will ultimately require a complex revision surgery to remove the infection.
In this study, impedance spectroscopy and differential pulse voltammetry were carried out in parallel to measure electrochemical and impedance properties of bacteria, allowing for identification and quantification of pyoverdine and pyocyanin; bacterial metabolites. Three
Pseudomonas
spp. (
P. aeruginosa
,
P. fluorescens
and
P. putida
) were assayed in liquid culture at OD600. The sensor was standardised with pyoverdine and pyocyanin, with an electrochemical reading taken every 30 minutes up to 4 hours. This assay was repeated with
Pseudomonas
spp. growing in biofilms in LB broth, with a screen-printed electrode as the solid surface. Readings were then used to correlate metabolite production to biofilm production in each
Pseudomonas
sp. Pyoverdine correlated with biofilm formation for all three assayed
Pseudomonas
, with variation in the quantity of metabolite produced between species. This allows the two metabolites to be used as indicators of biofilm mass on devices and surfaces.
PDF
