scholarly journals Surface charge modulation of rifampicin-loaded PLA nanoparticles to improve antibiotic delivery in Staphylococcus aureus biofilms

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
David Da Costa ◽  
Chloé Exbrayat-Héritier ◽  
Basile Rambaud ◽  
Simon Megy ◽  
Raphaël Terreux ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Surface Charge ◽  
Treatment Efficacy ◽  
Particle Migration ◽  
Bacterial Biofilm ◽  
Poly Lactic Acid ◽  
Retention Capacity ◽  
The Impact ◽  
Positively Charged ◽  
Antibiotic Delivery

Abstract Background After the golden age of antibiotic discovery, bacterial infections still represent a major challenge for public health worldwide. The biofilm mode of growth is mostly responsible for chronic infections that current therapeutics fail to cure and it is well-established that novel strategies must be investigated. Particulate drug delivery systems are considered as a promising strategy to face issues related to antibiotic treatments in a biofilm context. Particularly, poly-lactic acid (PLA) nanoparticles present a great interest due to their ability to migrate into biofilms thanks to their submicronic size. However, questions still remain unresolved about their mode of action in biofilms depending on their surface properties. In the current study, we have investigated the impact of their surface charge, firstly on their behavior within a bacterial biofilm, and secondly on the antibiotic delivery and the treatment efficacy. Results Rifampicin-loaded PLA nanoparticles were synthetized by nanoprecipitation and characterized. A high and superficial loading of rifampicin, confirmed by an in silico simulation, enabled to deliver effective antibiotic doses with a two-phase release, appropriate for biofilm-associated treatments. These nanoparticles were functionalized with poly-l-lysine, a cationic peptide, by surface coating inducing charge reversal without altering the other physicochemical properties of these particles. Positively charged nanoparticles were able to interact stronger than negative ones with Staphylococcus aureus, under planktonic and biofilm modes of growth, leading to a slowed particle migration in the biofilm thickness and to an improved retention of these cationic particles in biofilms. While rifampicin was totally ineffective in biofilms after washing, the increased retention capacity of poly-l-lysine-coated rifampicin-loaded PLA nanoparticles has been associated with a better antibiotic efficacy than uncoated negatively charged ones. Conclusions Correlating the carrier retention capacity in biofilms with the treatment efficacy, positively charged rifampicin-loaded PLA nanoparticles are therefore proposed as an adapted and promising approach to improve antibiotic delivery in S. aureus biofilms.

scholarly journals Moroccan Propolis: A Natural Antioxidant, Antibacterial, and Antibiofilm against Staphylococcus aureus with No Induction of Resistance after Continuous Exposure

2018 ◽  
Vol 2018 ◽  
pp. 1-19 ◽  
Author(s):  
Soukaïna El-Guendouz ◽  
Smail Aazza ◽  
Badiaa Lyoussi ◽  
Vassya Bankova ◽  
Milena Popova ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Quorum Sensing ◽  
Galleria Mellonella ◽  
Antioxidant Activities ◽  
Bacterial Biofilm ◽  
Continuous Exposure ◽  
Dependent Manner ◽  
Propolis Extract ◽  
Two Samples ◽  
The Impact

This study was performed to evaluate the total phenols, flavonoids, and antioxidant activities of twenty-four propolis samples from different regions of Morocco. In addition, two samples were screened regarding the antibacterial effect against four Staphylococcus aureus strains. Gas chromatography coupled to mass spectra (GC-MS) analysis was done for propolis samples used in antibacterial tests. The minimum inhibitory and minimum bactericidal concentration (MIC, MBC) were determined. The potential to acquire the resistance after sequential exposure of bacterial strains and the impact of adaptation to propolis on virulence using the Galleria mellonella were evaluated. Additionally, the effects of propolis extract on the bacterial adherence ability and its ability to inhibit the quorum sensing activity were also examined. Among the twenty-four extracts studied, the samples from Sefrou, Outat el Haj, and the two samples marketed in Morocco were the best for scavenging DPPH, ABTS, NO, peroxyl, and superoxide radicals as well as in scavenging of hydrogen peroxide. A strong correlation was found between the amounts of phenols, flavonoids, and antioxidant activities. Propolis extract at the MIC value (0.36 mg/mL) significantly reduced (p < 0.001) the virulence potential of S. aureus ATCC 6538 and the MRSA strains without leading to the development of resistance in the sequence of continuous exposure. It was able to impair the bacterial biofilm formation. The results have revealed that sample 1 reduces violacein production in a concentration dependent manner, indicating inhibition of quorum sensing. This extract has as main group of secondary metabolites flavonoids (31.9%), diterpenes (21.5%), and phenolic acid esters (16.5%).

scholarly journals Liposomes as a Nanoplatform to Improve the Delivery of Antibiotics into Staphylococcus aureus Biofilms

Pharmaceutics ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 321
Author(s):  
Magda Ferreira ◽  
Sandra N. Pinto ◽  
Frederico Aires-da-Silva ◽  
Ana Bettencourt ◽  
Sandra I. Aguiar ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Fibroblast Cell ◽  
Therapeutic Benefit ◽  
Bacterial Biofilm ◽  
In Vivo Studies ◽  
Health Concern ◽  
Free Form ◽  
Positively Charged

Staphylococcus aureus biofilm-associated infections are a major public health concern. Current therapies are hampered by reduced penetration of antibiotics through biofilm and low accumulation levels at infected sites, requiring prolonged usage. To overcome these, repurposing antibiotics in combination with nanotechnological platforms is one of the most appealing fast-track and cost-effective approaches. In the present work, we assessed the potential therapeutic benefit of three antibiotics, vancomycin, levofloxacin and rifabutin (RFB), through their incorporation in liposomes. Free RFB displayed the utmost antibacterial effect with MIC and MBIC50 below 0.006 µg/mL towards a methicillin susceptible S. aureus (MSSA). RFB was selected for further in vitro studies and the influence of different lipid compositions on bacterial biofilm interactions was evaluated. Although positively charged RFB liposomes displayed the highest interaction with MSSA biofilms, RFB incorporated in negatively charged liposomes displayed lower MBIC50 values in comparison to the antibiotic in the free form. Preliminary safety assessment on all RFB formulations towards osteoblast and fibroblast cell lines demonstrated that a reduction on cell viability was only observed for the positively charged liposomes. Overall, negatively charged RFB liposomes are a promising approach against biofilm S. aureus infections and further in vivo studies should be performed.

Effect of Polyphosphate on Removal of Endocrine-Disrupting Chemicals of Nonylphenol and Bisphenol-A by Activated Carbons

2005 ◽  
Vol 40 (4) ◽  
pp. 484-490 ◽  
Author(s):  
Keun J. Choi ◽  
Sang G. Kim ◽  
Chang W. Kim ◽  
Seung H. Kim
Keyword(s):  
Activated Carbon ◽  
Bisphenol A ◽  
Surface Charge ◽  
Activated Carbons ◽  
Endocrine Disrupting Chemicals ◽  
Dipole Interaction ◽  
High Affinity ◽  
Calcium Polyphosphate ◽  
Endocrine Disrupting ◽  
Positively Charged

Abstract This study examined the effect of polyphosphate on removal of endocrine-disrupting chemicals (EDCs) such as nonylphenol and bisphenol-A by activated carbons. It was found that polyphosphate aided in the removal of nonylphenol and bisphenol- A. Polyphosphate reacted with nonylphenol, likely through dipole-dipole interaction, which then improved the nonylphenol removal. Calcium interfered with this reaction by causing competition. It was found that polyphosphate could accumulate on carbon while treating a river. The accumulated polyphosphate then aided nonylphenol removal. The extent of accumulation was dependent on the type of carbon. The accumulation occurred more extensively with the wood-based used carbon than with the coal-based used carbon due to the surface charge of the carbon. The negatively charged wood-based carbon attracted the positively charged calcium-polyphosphate complex more strongly than the uncharged coal-based carbon. The polyphosphate-coated activated carbon was also effective in nonylphenol removal. The effect was different depending on the type of carbon. Polyphosphate readily attached onto the wood-based carbon due to its high affinity for polyphosphate. The attached polyphosphate then improved the nonylphenol removal. However, the coating failed to attach polyphosphate onto the coal-based carbon. The nonylphenol removal performance of the coal-based carbon remained unchanged after the polyphosphate coating.

scholarly journals Evaluation of a bone filler scaffold for local antibiotic delivery to prevent Staphylococcus aureus infection in a contaminated bone defect

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Karen E. Beenken ◽  
Mara J. Campbell ◽  
Aura M. Ramirez ◽  
Karrar Alghazali ◽  
Christopher M. Walker ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Bone Defect ◽  
Rabbit Model ◽  
In Vivo Studies ◽  
Bovine Bone ◽  
Bone Filler ◽  
Antibiotic Release ◽  
Local Antibiotic ◽  
Antibiotic Delivery

AbstractWe previously reported the development of an osteogenic bone filler scaffold consisting of degradable polyurethane, hydroxyapatite, and decellularized bovine bone particles. The current study was aimed at evaluating the use of this scaffold as a means of local antibiotic delivery to prevent infection in a bone defect contaminated with Staphylococcus aureus. We evaluated two scaffold formulations with the same component ratios but differing overall porosity and surface area. Studies with vancomycin, daptomycin, and gentamicin confirmed that antibiotic uptake was concentration dependent and that increased porosity correlated with increased uptake and prolonged antibiotic release. We also demonstrate that vancomycin can be passively loaded into either formulation in sufficient concentration to prevent infection in a rabbit model of a contaminated segmental bone defect. Moreover, even in those few cases in which complete eradication was not achieved, the number of viable bacteria in the bone was significantly reduced by treatment and there was no radiographic evidence of osteomyelitis. Radiographs and microcomputed tomography (µCT) analysis from the in vivo studies also suggested that the addition of vancomycin did not have any significant effect on the scaffold itself. These results demonstrate the potential utility of our bone regeneration scaffold for local antibiotic delivery to prevent infection in contaminated bone defects.

scholarly journals 309. The Impact of Addiction Medicine Consultation on Discharges Against Medical Advice in Patients with Opioid Use Disorder and Staphylococcus Aureus Bacteremia

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S152-S152
Author(s):  
Stephanie Spivack ◽  
Daniel Mueller ◽  
Peter Axelrod ◽  
Joseph D’Orazio
Keyword(s):  
Staphylococcus Aureus ◽  
Patient Population ◽  
Medical Advice ◽  
Index Admission ◽  
Opioid Use ◽  
Urban Hospital ◽  
Addiction Medicine ◽  
Against Medical Advice ◽  
Number Of Patients ◽  
The Impact

Abstract Background People who inject drugs (PWID) are at risk for infectious complications of their injection practices, including Staphylococcus aureus (SA) bacteremia. Prolonged hospitalization is sometimes required; however, rates of discharges against medical advice (AMA) are elevated in this patient population. Inadequate control of pain and opioid withdrawal are commonly cited. Our aim was to assess the effectiveness of addiction medicine consultation for preventing AMA discharges. Methods We performed a retrospective chart review of adult PWID admitted to an urban hospital with SA bacteremia between August 2016 and May 2018. Demographics, HIV and HCV status, and presence or absence of addiction medicine consultation were recorded. We assessed whether discharges were planned or AMA; the number of hospitalizations at 30 days, 90 days, and 1 year from index admission; and death within one year. EpiInfo6 was used for data analysis. Results A total of 360 patients with SA bacteremia were reviewed. Of these, 101 reported intravenous opioid use at admission. Average age was 37 years, and 64% were male. HIV and HCV were present in 13% and 82% of patients, respectively. Addiction medicine was consulted on 29 patients. Of these, 4/29 (13.8%) left AMA, compared to 27/72 (37.5%) of patients without an addiction consult (RR = 0.3678 [95% CI = 0.1412 - 0.9583], p = 0.02). Patients receiving addiction medicine consultation averaged 0.17 readmissions within 30 days of their index admission, compared to 0.39 readmissions in the group without addiction medicine consult (p = 0.27). Readmissions at 90 days and 1 year were also lower but not statistically significant. At 1 year, 6 deaths were observed; 2 who had addiction medicine consultation and 4 who did not. Conclusion Consultation with an addiction medicine specialist significantly reduced the number of patients discharged AMA in a high-risk cohort of PWID presenting with SA bacteremia. Numerically fewer readmissions occurred after consultation, though this difference was not statistically significant. Mortality in both groups was low. There were high rates of HIV and HCV in this patient population, suggesting a particularly vulnerable patient population, which warrants further study. Disclosures All Authors: No reported disclosures

scholarly journals Buoyancy control in ammonoid cephalopods refined by complex internal shell architecture

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
David J. Peterman ◽  
Kathleen A. Ritterbush ◽  
Charles N. Ciampaglio ◽  
Erynn H. Johnson ◽  
Shinya Inoue ◽  
...  
Keyword(s):  
Surface Tension ◽  
Water Retention Capacity ◽  
Functional Explanation ◽  
Retention Capacity ◽  
Biomechanical Stress ◽  
Liquid Retention ◽  
3D Printed ◽  
Functional Explanations ◽  
Hydrophilic Coatings ◽  
The Impact

AbstractThe internal architecture of chambered ammonoid conchs profoundly increased in complexity through geologic time, but the adaptive value of these structures is disputed. Specifically, these cephalopods developed fractal-like folds along the edges of their internal divider walls (septa). Traditionally, functional explanations for septal complexity have largely focused on biomechanical stress resistance. However, the impact of these structures on buoyancy manipulation deserves fresh scrutiny. We propose increased septal complexity conveyed comparable shifts in fluid retention capacity within each chamber. We test this interpretation by measuring the liquid retained by septa, and within entire chambers, in several 3D-printed cephalopod shell archetypes, treated with (and without) biomimetic hydrophilic coatings. Results show that surface tension regulates water retention capacity in the chambers, which positively scales with septal complexity and membrane capillarity, and negatively scales with size. A greater capacity for liquid retention in ammonoids may have improved buoyancy regulation, or compensated for mass changes during life. Increased liquid retention in our experiments demonstrate an increase in areas of greater surface tension potential, supporting improved chamber refilling. These findings support interpretations that ammonoids with complex sutures may have had more active buoyancy regulation compared to other groups of ectocochleate cephalopods. Overall, the relationship between septal complexity and liquid retention capacity through surface tension presents a robust yet simple functional explanation for the mechanisms driving this global biotic pattern.

scholarly journals 87. Utilization of Methicillin-Sensitive/Resistant Staphylococcus aureus Nares Screen to Decrease Vancomycin and Linezolid Use in Hospitalized Patients with Respiratory Infections

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S60-S60
Author(s):  
Noor F Zaidan ◽  
Rachel S Britt ◽  
David Reynoso ◽  
R Scott Ferren
Keyword(s):  
Staphylococcus Aureus ◽  
Respiratory Infections ◽  
Intervention Group ◽  
Kidney Injury ◽  
Post Intervention ◽  
Gram Positive ◽  
Stewardship Program ◽  
Screening Protocol ◽  
The Impact ◽  
Post Intervention Group

Abstract Background Pharmacist-driven protocols for utilization of methicillin-resistant Staphylococcus aureus (MRSA) nares screenings have shown to decrease duration of empiric gram-positive therapy and rates of acute kidney injury (AKI) in patients with respiratory infections. This study evaluated the impact of a pharmacist-driven MRSA nares screening protocol on duration of vancomycin or linezolid therapy (DT) in respiratory infections. Methods Patients aged 18 years and older with a medication order of vancomycin or linezolid for respiratory indication(s) were included. The MRSA nares screening protocol went into effect in October 2019. The protocol allowed pharmacists to order an MRSA nares polymerase chain reaction (PCR) for included patients, while the Antimicrobial Stewardship Program (ASP) made therapeutic recommendations for de-escalation of empiric gram-positive coverage based on negative MRSA nares screenings, if clinically appropriate. Data for the pre-intervention group was collected retrospectively for the months of October 2018 to March 2019. The post-intervention group data was collected prospectively for the months of October 2019 to March 2020. Results Ninety-seven patients were evaluated within both the pre-intervention group (n = 50) and post-intervention group (n = 57). Outcomes for DT (38.2 hours vs. 30.9 hours, P = 0.601) and AKI (20% vs. 14%, P = 0.4105) were not different before and after protocol implementation. A subgroup analysis revealed a significant reduction in DT within the pre- and post-MRSA PCR groups (38.2 hours vs. 24.8 hours, P = 0.0065) when pharmacist recommendations for de-escalation were accepted. Conclusion A pharmacist-driven MRSA nares screening protocol did not affect the duration of gram-positive therapy for respiratory indications. However, there was a reduction in DT when pharmacist-driven recommendations were accepted. Disclosures All Authors: No reported disclosures

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