Acne vulgaris: the skin microbiome, antibiotics and whether natural products could be considered a suitable alternative treatment?

Acne vulgaris is a common, chronic inflammatory skin disease manifested as inflammatory and non-inflammatory lesions typically associated with Cutibacterium acnes. However, its pathogenesis is not fully understood nor is the complexity of the skin microbiome and how it contributes to the development of acne. Whilst acne is not a typical bacterial infection, antibiotics have been the mainstay of treatment for over 50 years. Now, with the development of multi-drug resistant organisms and the emergence of resistant C. acnes strains; the question is are antibiotics still an appropriate treatment method or could natural products provide a suitable alternative? Research into alternative treatments is a growing field due to the increase in resistant organisms, there is a multitude of research into natural products due to their antimicrobial potential and the multiple mechanisms of action. Melaleuca alternifolia is a key natural product of interest in the treatment of acne due to its documented use throughout history and its prevalence in over the counter treatments. Green Tea is a more recent natural product of interest due to its composition of polyphenols, which give rise to both antimicrobial and anti-inflammatory properties. However, research also suggests that a synergistic approach of natural products may be the way forward

Phenotypic detection of AmpC β-lactamases, extended-spectrum- β-lactamases and metallo-β-lactamases in Enterobacteriaceae using a resazurin microtitre assay with inhibitor-based methods.

Dissemination of antibiotic resistance in Enterobacteriaceae mediated by AmpC, ESBL and MBL β-lactamases is clinically significant. A simple, relatively quick method for the detection of these resistance phenotypes would greatly improve chemotherapeutic recommendation. This technology would provide valuable input in our surveillance of resistance on a global stage, particularly if the methodology could be applicable to resource poor settings. A resazurin microtitre plate (RMP) assay incorporating cloxacillin, clavulanic acid, and EDTA for the rapid phenotypic identification of AmpC, Extended-spectrum-β-lactmase (ESBL), metallo-β-lactamase (MBL) and the co-existence of β-lactamases has been developed. A total of 47 molecularly characterised Enterobacteriaceae clinical isolates producing AmpCs, ESBLs, co-producers of ESBL and AmpC, MBLs, and co-producers of ESBL and MBL were phenotypically examined using the RMP assay. The ceftazidime (CAZ)-based and cefotaxime (CTX)-based RMP assay successfully detected all 16 AmpC, 14 ESBL, 9 MBL producers, 6 ESBL-AmpC co-producers, and 2 ESBL-MBL co-producers without false positive results. The CAZ-based assay was more reliable in detecting AmpC alone, while the CTX-based assay performed better in identifying co-producers of ESBL and AmpC. There was no difference in detection of ESBL and MBL producers. The findings of the present study suggest that use of the RMP assay with particular β-lactamase inhibitors explicitly detects three different β-lactamases, as well as co-existence of β-lactamases within 6 h after initial isolation of the pathogen. This assay is applicable to carry out in any laboratory, is cost-effective and easy to interpret. It could be implemented in screening patients, controlling infection and for surveillance purposes

RESEARCH ACTIVITIES IN THE CENTRE FOR NATURAL PRODUCTS DISCOVERY IN 2023

In 2023, the Centre for Natural Products Discovery (CNPD) made significant strides in the scientific community through a series of impactful research initiatives. These efforts underscore our commitment to harnessing the world’s natural resources to advance health. The fertile research environment at the CNPD has given rise to various sections, each contributing innovative and practical applications. Our goal here is to provide a concise overview of our research activities for the year. While this summary is not exhaustive, it focuses on the work of our section leaders, which in turn encompasses the contributions of numerous other researchers both within and outside the CNPD

Iron binding compounds produced by novel actinomycetes

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Kinetic and Equilibrium Isotherm Studies for the Removal of Tetracycline from Aqueous Solution Using Engineered Sand Modified with Calcium Ferric Oxides

The novel aspect of this research is the fabrication, characterisation, and application of an engineered adsorbent made from quartz sand coated with calcium ferric oxides (QS/CFO) derived from the wastepaper sludge ash (WPSA) for the removal of tetracycline (TC) from synthetic water. Initially, the new adsorbent was fabricated using a Ca/Fe molar ratio, sand/FeCl3 ratio, pH (of synthesising environment), ethylene glycol dose, and temperature of 1:0.75, 1:1, 12, 6 mL/100 mL, and 95 °C, respectively. Then, the new adsorbent was applied to treat water having 50 mg/L of TC in batch experiments, taking into account the effects of the contact time (0–180 min), pH of water (2–12), the dose of adsorbent (0.05–0.5 g), and agitation speed (0–250 rpm). The results obtained proved the engineered adsorbent can remove as much as 90% of the TC (adsorption capacity of 21.96 mg/g) within 180 min at an initial pH, adsorbent dosage, and agitation speed of 7, 0.3 g per 50 mL, and 200 rpm, respectively. It was also found that the pseudo-second-order model describes the kinetic measurements better than the pseudo-first-order model, which indicates that the TC molecules have been bonded with the prepared sorbent through chemical forces. Furthermore, the intra-particle diffusion model results demonstrated that the diffusion mechanism plays a significant role in TC adsorption; however, it was not the predominant one. Finally, the outcomes of the characterisation analysis proved that the newly formed layer on the quartz sand substantially contributed to the removal of the TC from the contaminated water

Eco-friendly remediation of tetracycline antibiotic from polluted water using waste-derived surface re-engineered silica sand

Abstract A new green reactive adsorbent (calcium ferric oxide silica sand (CFO-SS)) made from wastepaper sludge ash and ferric ions was synthesised and shown to remove tetracycline antibiotics (TC) from contaminated water effectively. The synthesised sand was dried at 95 °C, and a series of batch and fixed bed experiments were performed to determine the optimum operating conditions. Results showed that the adsorption capacity of the CFO-SS increases with the concentration gradient between the solid and liquid phases. 0.3 g of the new adsorbent was proven sufficient to remove more than 90% of the TC at a pollutant dose of 50 mg/L in 50 mL of simulated groundwater with an agitation speed of 200 rpm for 3 h. The adsorption isotherm followed the Langmuir isotherm model, with a loading capacity of 21.96 mg/g at pH 7, while the Pseudo second-order model best described the absorption kinetics. The adsorption mechanisms proposed included electrostatic interaction, intraparticle diffusion, hydrogen bonding, and cation-π interactions. Characterisation investigations revealed that the newly precipitated oxides on silica sand play an essential role in TC adsorption support. In fixed-bed experiments, it was discovered that reducing the flow rate and inflow concentration of TC and increasing the sorbent mass significantly extended the lifetime of the produced sorbent in the packed column. The measured breakthrough curves were best fit with the Adams-Bohart and the Clark models, as they provided the highest square root number (R2) values. Finally, considering the efficacy of CFO-SS in TC adsorption performance, it can be noted that the novel synthesised reactive material is an efficient and environmentally friendly material for TC removal, and it presents a potential solution to resolving the challenge of TC-rich groundwater

A Comprehensive Review for Groundwater Contamination and Remediation: Occurrence, Migration and Adsorption Modelling

The provision of safe water for people is a human right; historically, a major number of people depend on groundwater as a source of water for their needs, such as agricultural, industrial or human activities. Water resources have recently been affected by organic and/or inorganic contaminants as a result of population growth and increased anthropogenic activity, soil leaching and pollution. Water resource remediation has become a serious environmental concern, since it has a direct impact on many aspects of people’s lives. For decades, the pump-and-treat method has been considered the predominant treatment process for the remediation of contaminated groundwater with organic and inorganic contaminants. On the other side, this technique missed sustainability and the new concept of using renewable energy. Permeable reactive barriers (PRBs) have been implemented as an alternative to conventional pump-and-treat systems for remediating polluted groundwater because of their effectiveness and ease of implementation. In this paper, a review of the importance of groundwater, contamination and biological, physical as well as chemical remediation techniques have been discussed. In this review, the principles of the permeable reactive barrier’s use as a remediation technique have been introduced along with commonly used reactive materials and the recent applications of the permeable reactive barrier in the remediation of different contaminants, such as heavy metals, chlorinated solvents and pesticides. This paper also discusses the characteristics of reactive media and contaminants’ uptake mechanisms. Finally, remediation isotherms, the breakthrough curves and kinetic sorption models are also being presented. It has been found that groundwater could be contaminated by different pollutants and must be remediated to fit human, agricultural and industrial needs. The PRB technique is an efficient treatment process that is an inexpensive alternative for the pump-and-treat procedure and represents a promising technique to treat groundwater pollution. Validerad;2021;Nivå 2;2021-10-01 (johcin)</p

Antimicrobial activity of kojic acid from endophytic fungus Colletotrichum gloeosporioides isolated from Sonneratia apetala, a mangrove plant of the Sundarbans

Objective: To isolate and evaluate the antimicrobial activity of the active principle(s) from the ethyl acetate (EtOAc) extract of endophytic fungus Colletotrichum gloeosporioides (C. gloeosporioides) isolated from Sonneratia apetala. Methods: Water agar technique was used to isolate the fungus, and both microscopic and molecular techniques were used for identification of the strain. Potato dextrose broth was used to grow the fungus in large-scale. Reversed-phase preparative HPLC analysis was performed to isolate the major active compound, kojic acid. The EtOAc extract and kojic acid were screened for their antimicrobial activity against two Gram-positive and two Gram-negative bacteria as well as a fungal strain using the resazurin 96-well microtitre plate antimicrobial assay. Results: The fungus C. gloeosporioides was isolated from the leaves of Sonneratia apetala. Initial identification of the fugal isolate was carried out using spore characteristics observed under the microscope. Subsequently, the ITS1-5.8S-ITS2 sequencing was employed for species-level identification of the fungus C. gloeosporioides. Five litres of liquid culture of the fungus produced approximately 610 mg of a mixture of secondary metabolites. Kojic acid (1) was isolated as the main secondary metabolite present in the fungal extract, and the structure was confirmed by 1D, 2D NMR and mass spectrometry. The EtOAc extract and compound 1 exhibited considerable antimicrobial activity against all tested microorganisms. Whilst the minimum inhibitory concentration (MIC) values from the EtOAc extract ranged between 2.4× 10-4 mg/mL and 2.5 mg/mL, those of kojic acid (1) were between 0.125 mg/mL and 1 mg/mL. The EtOAc extract and kojic acid (1) were most active against Pseudomonas aeruginosa (MIC = 2.4×10-4 mg/mL) and Micrococcus luteus (MIC = 0.125 mg/mL), respectively. Conclusions: The results revealed that the endophytic fungus C. gloeosporioides could be a good source of commercially important kojic acid, which exhibited antimicrobial properties