On the Etiological Relevance of Escherichia coli and Staphylococcus aureus in Superficial and Deep Infections - A Hypothesis-Forming, Retrospective Assessment

Rhamnolipid-Modified PHB-Ectoine Nanoparticles for Multifunctional Skin Protection Against UVB, Irritation, and Bacteria

Rhamnolipid, poly(R)-3-hydroxybutyrate (PHB), and ectoine are sustainable compounds produced by specific bacteria known for their protective benefits, including promoting skin health in applications, such as facial wash, sunscreens, and moisturizers. These compounds have been extensively studied due to their unique physicochemical properties and biocompatibility. Leveraging these beneficial properties, this study aimed to create a multifunctional protective formulation by synthesizing nanoparticles from PHB and ectoine, which are acknowledged for their anti-ultraviolet B (UVB) and anti-irritation properties. The covalent bonding of PHB and ectoine was achieved using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), and the nanoparticles were produced through centrifugation. The synthesized nanoparticle (PHB-ectoine NPs) was physicochemically characterized and tested for anti-irritation and anti-UVB properties in vitro. The characterization revealed a homogeneous spherical shape with a distinct layered structure, primarily composed of carbon and oxygen. The PHB-ectoine NPs measured 527 ± 228 nm in size, had a zeta potential of -61.47 ± 0.64 mV, and exhibited notably higher anti-irritant and anti-UVB activities compared to PHB alone, by over 10 and 4 times, respectively. Furthermore, the addition of a rhamnolipid solution as a dispersant provided the nanofluid with antibacterial properties againstStaphylococcus aureus. These results indicate that the rhamnolipid-PHB-ectoine nanoformulation shows significant potential as a multifunctional skin protective agent with anti-irritation, anti-UVB, and antibacterial capabilities.

New strategies to enhance antimicrobial photo-sonodynamic therapy based on nanosensitizers against bacterial infections

The rapid evolution and spread of multidrug resistance among bacterial pathogens has significantly outpaced the development of new antibiotics, underscoring the urgent need for alternative therapies. Antimicrobial photodynamic therapy and antimicrobial sonodynamic therapy have emerged as promising treatments. Antimicrobial photodynamic therapy relies on the interaction between light and a photosensitizer to produce reactive oxygen species, which are highly cytotoxic to microorganisms, leading to their destruction without fostering resistance. Antimicrobial sonodynamic therapy, a novel variation, substitutes ultrasound for light to activate the sonosensitizers, expanding the therapeutic reach. To increase the efficiency of antimicrobial photodynamic therapy and antimicrobial sonodynamic therapy, the combination of these two methods, known as antimicrobial photo-sonodynamic therapy, is currently being explored and considered a promising approach. Recent advances, particularly in the application of nanomaterials, have further enhanced the efficacy of these therapies. Nanosensitizers, due to their improved reactive oxygen species generation and targeted delivery, offer significant advantages in overcoming the limitations of conventional sensitizers. These breakthroughs provide new avenues for treating bacterial infections, especially multidrug-resistant strains and biofilm-associated infections. Continued research, including comprehensive clinical studies, is crucial to optimizing nanomaterial-based antimicrobial photo-sonodynamic therapy for clinical use, ensuring their effectiveness in real-world applications.

Advanced pullulan nanofibers reinforced by cellulose fibrils as drug carriers for salicylic acid

The goal of the current work is to showcase the synthesis of homogeneous pullulan nanofibers that are strengthened by the addition of cellulose nanofibrils (CNF). One of the main difficulties this study faced was determining the ideal water/organic solvent ratio for the electrospinning process, which would allow for the maximum reduction in the amount of organic solvent (DMF or DMSO) needed. The rheological behavior of electrospinning solutions was modulated by varying both, the pullulan concentration and solvent system composition. The amount of CNF in the composition significantly affects the properties of the created nanofibers. When the CNF content increased from 1 % to 5 %, the diameter of the fibers decreases from 284 nm to 90 nm. This is attributed to the enhanced conductivity and surface charge density of the solution jet. The as prepared nanofibres can hold a variety of drugs and can be used to create novel formulations for various biomedical purposes. The nanofibres were tested for salicylic acid incorporation and release. Drug release exhibited zero-order kinetics, suggesting that the concentration remained unaffected by the rate of release. Furthermore, the nanofibres demonstrated remarkable antibacterial activity against both Gram-positive and Gram-negative bacteria.

Development of erythromycin loaded PLGA nanoparticles for improved drug efficacy and sustained release against bacterial infections and biofilm formation

Bacterial infections are a common cause of sepsis, often leading to high patient mortality. Such infections are challenging to treat due to bacterial resistance to many existing drugs. Erythromycin (Ery) is a macrolide antibiotic used against bacterial infections with reported resistance. Recently, synthetic poly-lactide co-glycolic acid (PLGA) polymer nanoparticles (NPs) have displayed improved drug delivery characteristics and biocompatibility. In this study, PLGA-Ery NPs were synthesized by the o/w emulsion diffusion method, having a particle size of 159 ± 23 nm and displayed 71.89 % of encapsulation efficiency. The PLGA-Ery NPs showed 1.5, 2.1 and 1.5-fold improved MIC and antibacterial efficacy against E. coli, S. aureus, and P. aeruginosa, respectively than the pure drug. As illustrated by scanning electron microscopy, PLGA-Ery NPs caused damage to the bacterial cell walls. Furthermore, a surface coating with PLGA-Ery NPs on a glass surface showed efficient inhibition (>90 %) of the biofilm formation by P. aeruginosa, as determined by fluorescence microscopy and MTT assay. This study demonstrates that PLGA-Ery NPs can increase the efficiency of erythromycin and can suppress the growth and biofilm formation of P. aeruginosa. Such polymeric nanoparticles drug nanoformulations have potential as an antimicrobial and as a surface coating for medical devices.

Green synthesis of metal nanoparticles and study their anti-pathogenic properties against pathogens effect on plants and animals

According to an estimate, 30% to 40%, of global fruit are wasted, leading to post harvest losses and contributing to economic losses ranging from $10 to $100 billion worldwide. Among, all fruits the discarded portion of oranges is around 20%. A novel and value addition approach to utilize the orange peels is in nanoscience. In the present study, a synthesis approach was conducted to prepare the metallic nanoparticles (copper and silver); by utilizing food waste (Citrus plant peels) as bioactive reductants. In addition, the Citrus sinensis extracts showed the reducing activity against metallic salts copper chloride and silver nitrate to form Cu-NPs (copper nanoparticles) and Ag-NPs (Silver nanoparticles). The in vitro potential of both types of prepared nanoparticles was examined against plant pathogenic bacteria Erwinia carotovora (Pectobacterium carotovorum) and pathogens effect on human health Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Moreover, the in vivo antagonistic potential of both types of prepared nanoparticles was examined by their interaction with against plant (potato slices). Furthermore, additional antipathogenic (antiviral and antifungal) properties were also examined. The statistical analysis was done to explain the level of significance and antipathogenic effectiveness among synthesized Ag-NPs and Cu-NPs. The surface morphology, elemental description and size of particles were analyzed by scanning electron microscopy, transmission electron microscopy, energy-dispersive spectroscopy and zeta sizer (in addition polydispersity index and zeta potential). The justification for the preparation of particles was done by UV-Vis Spectroscopy (excitation peaks at 339 nm for copper and 415 nm for silver) and crystalline nature was observed by X-ray diffraction. Hence, the prepared particles are quite effective against soft rot pathogens in plants and can also be used effectively in some other multifunctional applications such as bioactive sport wear, surgical gowns, bioactive bandages and wrist or knee compression bandages, etc.

Derivation of a novel antimicrobial peptide from the Red Sea Brine Pools modified to enhance its anticancer activity against U2OS cells

Cancer associated drug resistance is a major cause for cancer aggravation, particularly as conventional therapies have presented limited efficiency, low specificity, resulting in long term deleterious side effects. Peptide based drugs have emerged as potential alternative cancer treatment tools due to their selectivity, ease of design and synthesis, safety profile, and low cost of manufacturing. In this study, we utilized the Red Sea metagenomics database, generated during AUC/KAUST Red Sea microbiome project, to derive a viable anticancer peptide (ACP). We generated a set of peptide hits from our library that shared similar composition to ACPs. A peptide with a homeodomain was selected, modified to improve its anticancer properties, verified to maintain high anticancer properties, and processed for further in-silico prediction of structure and function. The peptide's anticancer properties were then assessed in vitro on osteosarcoma U2OS cells, through cytotoxicity assay (MTT assay), scratch-wound healing assay, apoptosis/necrosis detection assay (Annexin/PI assay), RNA expression analysis of Caspase 3, KI67 and Survivin, and protein expression of PARP1. L929 mouse fibroblasts were also assessed for cytotoxicity treatment. In addition, the antimicrobial activity of the peptide was also examined on E coli and S. aureus, as sample representative species of the human bacterial microbiome, by examining viability, disk diffusion, morphological assessment, and hemolytic analysis. We observed a dose dependent cytotoxic response from peptide treatment of U2OS, with a higher tolerance in L929s. Wound closure was debilitated in cells exposed to the peptide, while annexin fluorescent imaging suggested peptide treatment caused apoptosis as a major mode of cell death. Caspase 3 gene expression was not altered, while KI67 and Survivin were both downregulated in peptide treated cells. Additionally, PARP-1 protein analysis showed a decrease in expression with peptide exposure. The peptide exhibited minimal antimicrobial activity on critical human microbiome species E. coli and S. aureus, with a low inhibition rate, maintenance of structural morphology and minimal hemolytic impact. These findings suggest our novel peptide displayed preliminary ACP properties against U2OS cells, through limited specificity, while triggering apoptosis as a primary mode of cell death and while having minimal impact on the microbiological species E. coli and S. aureus.

Salicylic Acid Release from Syndiotactic Polystyrene Staple Fibers

Films and fibers of syndiotactic polystyrene (sPS), being amorphous or exhibiting nanoporous crystalline (NC) or dense crystalline phases, were loaded with salicylic acid (SA), a relevant non-volatile antimicrobial molecule. In the first section of the paper, sPS/SA co-crystalline (CC) δ form is characterized, mainly by wide angle X-ray diffraction (WAXD) patterns and polarized Fourier transform infrared (FTIR) spectra. The formation of sPS/SA δ CC phases allows the preparation of sPS fibers even with a high content of the antibacterial guest, which is also retained after repeated washing procedures at 65 °C. A preparation procedure starting from amorphous fibers is particularly appropriate because involves a direct formation of the CC δ form and a simultaneous axial orientation. The possibility of tuning drug amount and release kinetics, by simply selecting suitable crystalline phases of a commercially available polymer, makes sPS fibers possibly useful for many applications. In particular, fibers with δ CC forms, which retain SA molecules in their crystalline phases, could be useful for antimicrobial textiles and fabrics. Fibers with the dense γ form which easily release SA molecules, because they are only included in their amorphous phases, could be used for promising SA-based preparations for antibacterial purposes in food processing and preservation and public health. Finally, using a cell-based assay system and antibacterial tests, we investigated the cellular activity, toxicity and antimicrobial properties of amorphous, δ CC forms and dense γ form of sPS fibers loaded with different contents of SA.

Clinical epidemiology and case fatality due to antimicrobial resistance in Germany: a systematic review and meta-analysis, 1 January 2010 to 31 December 2021

BackgroundAntimicrobial resistance (AMR) is of public health concern worldwide.AimWe aimed to summarise the German AMR situation for clinicians and microbiologists.MethodsWe conducted a systematic review and meta-analysis of 60 published studies and data from the German Antibiotic-Resistance-Surveillance (ARS). Primary outcomes were AMR proportions in bacterial isolates from infected patients in Germany (2016-2021) and the case fatality rates (2010-2021). Random and fixed (common) effect models were used to calculate pooled proportions and pooled case fatality odds ratios, respectively.ResultsThe pooled proportion of meticillin resistance in Staphylococcus aureus infections (MRSA) was 7.9% with a declining trend between 2014 and 2020 (odds ratio (OR) = 0.89; 95% CI: 0.886-0.891; p < 0.0001), while vancomycin resistance in Enterococcus faecium (VRE) bloodstream infections increased (OR = 1.18; (95% CI: 1.16-1.21); p < 0.0001) with a pooled proportion of 34.9%. Case fatality rates for MRSA and VRE were higher than for their susceptible strains (OR = 2.29; 95% CI: 1.91-2.75 and 1.69; 95% CI: 1.22-2.33, respectively). Carbapenem resistance in Gram-negative pathogens (Klebsiella pneumoniae, Acinetobacter baumannii, Enterobacter spp. and Escherichia coli) was low to moderate (< 9%), but resistance against third-generation cephalosporins and fluoroquinolones was moderate to high (5-25%). Pseudomonas aeruginosa exhibited high resistance against carbapenems (17.0%; 95% CI: 11.9-22.8), third-generation cephalosporins (10.1%; 95% CI: 6.6-14.2) and fluoroquinolones (24.9%; 95% CI: 19.3-30.9). Statistical heterogeneity was high (I2 > 70%) across studies reporting resistance proportions.ConclusionContinuous efforts in AMR surveillance and infection prevention and control as well as antibiotic stewardship are needed to limit the spread of AMR in Germany.

Single-step antibiotic-mediated synthesis of kanamycin-conjugated gold nanoparticles for broad-spectrum antibacterial applications

Widespread and irrational use of antibiotics results in the development of antibiotic-resistant bacteria. Thus, there is a need to develop novel antibacterial agents in order to replace conventional antibiotics and to increase the efficacy of already existing antibiotics by combining them with other materials. Herein, a single-step antibiotic-mediated synthesis of antibiotic-conjugated gold nanoparticles is reported. In this single-step method antibiotic Kanamycin, an aminoglycoside itself plays the role of reducing as well as capping agent by reducing gold salt into gold nanoparticles. The kanamycin-conjugated gold nanoparticles (Kan-AuNPs) were confirmed by UV-Visible spectroscopy and further physico-chemically characterized by various instrumental techniques. Synthesized Kan-AuNPs showed broad-spectrum antibacterial activity against Gram-positive Staphylococcus aureus as well as Gram-negative Escherichia coli bacterial strains. They are also found to be effective against Pseudomonas aeruginosa and pathogenic E. coli isolated from urinary tract infections (UTIs) patients, which are responsible to cause hospital-acquired infections like nosocomial, burn wound and UTIs. The minimum inhibitory concentration (MIC) of Kan-AuNPs is 50 μg ml^-1 for S. aureus and E. coli, 125 μg ml^-1 for P. aeruginosa and 100 μg ml^-1 for E. coli isolated from UTIs patients. It is also evident that the MIC of Kan-AuNPs for antibacterial activity is lower as compared to antibiotic kanamycin alone for all bacterial strains. Hence, the one-step strategy of synthesis for Kan-AuNPs is a suitable strategy for fighting infectious bacterial strains in hospitals, healthcare and the pharmaceutical industry.

Waste Glass-Derived Tobermorite Carriers for Ag+ and Zn2+ Ions

In this study, the layer-lattice calcium silicate hydrate mineral, tobermorite, was synthesized from waste green or amber container glass and separately ion-exchanged with Ag+ or Zn2+ ions under batch conditions. Hydrothermal treatment of stoichiometrically adjusted mixtures of waste glass and calcium oxide in 4 M NaOH(aq) at 125 °C yielded tobermorite products of ~75% crystallinity with mean silicate chain lengths of 17 units after one week. Maximum uptake of Zn2+ ions, ~0.55 mmol g−1, occurred after 72 h, and maximum uptake of Ag+ ions, ~0.59 mmol g−1, was established within 6 h. No significant differences in structure or ion-exchange behavior were observed between the tobermorites derived from either green or amber glass. Composite membranes of the biopolymer, chitosan, incorporating the original or ion-exchanged tobermorite phases were prepared by solvent casting, and their antimicrobial activities against S. aureus and E. coli were evaluated using the Kirby–Bauer assay. S. aureus and E. coli formed biofilms on pure chitosan and chitosan surfaces blended with the original tobermorites, whereas the composites containing Zn2+-substituted tobermorites defended against bacterial colonization. Distinct, clear zones were observed around the composites containing Ag+-substituted tobermorites which arose from the migration of the labile Ag+ ions from the lattices. This research has indicated that waste glass-derived tobermorites are functional carriers for antimicrobial ions with potential applications as fillers in polymeric composites to defend against the proliferation and transmission of pathogenic bacteria.

Novel scaffold based graphene oxide doped electrospun iota carrageenan/polyvinyl alcohol for wound healing and pathogen reduction: in-vitro and in-vivo study

Wound healing is a complicated multicellular process that involves several kinds of cells including macrophages, fibroblasts, endothelial cells, keratinocytes and platelets that are leading to their differentiation towards an anti-inflammatory response for producing several chemokines, cytokine and growth factors. In this study, electrospun nanofiber scaffold named (MNS) is composed of polyvinyl alcohol (PVA)/iota carrageenan (IC) and doped with partially reduced graphene oxide (prGO) that is successfully synthesized for wound healing and skin repair. The fabricated MNS was tested in case of infection and un-infection with E. coli and Staphylococcus and in both of the presence and in the absence of yeast as a natural nutritional supplement. Numerous biochemical parameters including total protein, albumin, urea and LDH, and hematological parameters were evaluated. Results revealed that the MNS was proved to be effective on most of the measured parameters and had exhibited efficient antibacterial inhibition activity. Whereas it can be used as an effective antimicrobial agent in wound healing, however, histopathological findings confirmed that the MNS caused re-epithelialization and the presence of yeast induced hair follicles growth and subsequently it may be used to hide formed head wound scar.

The global prevalence of fusidic acid resistance in clinical isolates of Staphylococcus aureus: a systematic review and meta-analysis

BACKGROUND AND AIM

Staphylococcus aureus (S. aureus) is one of the most common pathogens causing nosocomial and community-acquired infections with high morbidity and mortality rates. Fusidic acid has been increasingly used for the treatment of infections due to methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA). The present study aimed to determine the precise prevalence of fusidic acid resistant MRSA (FRMRSA), fusidic acid resistant MSSA (FRMSSA), and total fusidic acid resistant S. aureus (FRSA) on a global scale.

METHODS

Several international databases including Medline, Embase, and the Web of Sciences were searched (2000-2020) to discern studies addressing the prevalence of FRSA, FRMRSA, and FRMSSA. STATA (version14) software was used to interpret the data.

RESULTS

Of the 1446 records identified from the databases, 215 studies fulfilled the eligibility criteria for the detection of FRSA (208 studies), FRMRSA (143 studies), and FRMSSA (71 studies). The analyses manifested that the global prevalence of FRSA, FRMRSA, and FRMSSA was 0.5%, 2.6% and 6.7%, respectively.

CONCLUSION

This meta-analysis describes an increasing incidence of FRSA, FRMSSA, and FRMRSA. These results indicate the need for prudent prescription of fusidic acid to stop or diminish the incidence of fusidic acid resistance as well as the development of strategies for monitoring the efficacy of fusidic acid use.

The Drug-Loaded Electrospun Poly(ε-Caprolactone) Mats for Therapeutic Application

Diclofenac sodium salt (DSS)-loaded electrospun nanofiber mats on the base of poly(ε-caprolactone) (PCL) were investigated as biocompatible nanofibrous mats for medical applications with the ability to inhibit bacterial infections. The paper presents the characteristics of fibrous mats made by electrospinning and determines the effect of medicament on the fiber morphology, chemical, mechanical and thermal properties, as well as wettability. PCL and DSS-loaded PCL nanofibrous mats were characterized using scanning electron microscopy, transmission electron microscopy, attenuated total reflectance-Fourier transform infrared spectrometry, dynamic mechanical analysis, and contact angle measurements. Electron paramagnetic resonance measurements confirmed the lifetime of DSS before and after application of high voltage during the electrospinning process. In vitro biocompatibility was studied, and it was proved to be of good viability with ~92% of the diploid human cells culture line composed of lung fibroblast (MRC 5) after 48 h of incubation. Moreover, the significant activity of DSS-loaded nanofibers against cancer cells, Ca Ski and HeLa, was established as well. It was shown that 12.5% (m/V) is the minimal concentration for antibacterial activity when more than 99% of Escherichia coli (Gram-negative) and 99% of Staphylococcus aureus (Gram-positive) have been exterminated.