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Antibiotics ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 107
Sahra Fonseca ◽  
Marie-Pierre Cayer ◽  
K. M. Tanvir Ahmmed ◽  
Nima Khadem-Mohtaram ◽  
Steve J. Charette ◽  

Technological innovations and quality control processes within blood supply organizations have significantly improved blood safety for both donors and recipients. Nevertheless, the risk of transfusion-transmitted infection remains non-negligible. Applying a nanoparticular, antibacterial coating at the surface of medical devices is a promising strategy to prevent the spread of infections. In this study, we characterized the antibacterial activity of an SiO2 nanoparticular coating (i.e., the “Medical Antibacterial and Antiadhesive Coating” [MAAC]) applied on relevant polymeric materials (PM) used in the biomedical field. Electron microscopy revealed a smoother surface for the MAAC-treated PM compared to the reference, suggesting antiadhesive properties. The antibacterial activity was tested against selected Gram-positive and Gram-negative bacteria in accordance with ISO 22196. Bacterial growth was significantly reduced for the MAAC-treated PVC, plasticized PVC, polyurethane and silicone (90–99.999%) in which antibacterial activity of ≥1 log reduction was reached for all bacterial strains tested. Cytotoxicity was evaluated following ISO 10993-5 guidelines and L929 cell viability was calculated at ≥90% in the presence of MAAC. This study demonstrates that the MAAC could prevent bacterial contamination as demonstrated by the ISO 22196 tests, while further work needs to be done to improve the coating processability and effectiveness of more complex matrices.

2022 ◽  
Vol 12 ◽  
Brian A. Pettygrove ◽  
Heidi J. Smith ◽  
Kyler B. Pallister ◽  
Jovanka M. Voyich ◽  
Philip S. Stewart ◽  

The goal of this study was to quantify the variability of confocal laser scanning microscopy (CLSM) time-lapse images of early colonizing biofilms to aid in the design of future imaging experiments. To accomplish this a large imaging dataset consisting of 16 independent CLSM microscopy experiments was leveraged. These experiments were designed to study interactions between human neutrophils and single cells or aggregates of Staphylococcus aureus (S. aureus) during the initial stages of biofilm formation. Results suggest that in untreated control experiments, variability differed substantially between growth phases (i.e., lag or exponential). When studying the effect of an antimicrobial treatment (in this case, neutrophil challenge), regardless of the inoculation level or of growth phase, variability changed as a frown-shaped function of treatment efficacy (i.e., the reduction in biofilm surface coverage). These findings were used to predict the best experimental designs for future imaging studies of early biofilms by considering differing (i) numbers of independent experiments; (ii) numbers of fields of view (FOV) per experiment; and (iii) frame capture rates per hour. A spreadsheet capable of assessing any user-specified design is included that requires the expected mean log reduction and variance components from user-generated experimental results. The methodology outlined in this study can assist researchers in designing their CLSM studies of antimicrobial treatments with a high level of statistical confidence.

Jianxiong Hao ◽  
Junyi Zhang ◽  
Xueqi Zheng ◽  
Dandan Zhao

Abstract In the present study, the bactericidal efficacy of slightly acidic electrolyzed water (SAEW) against L. monocytogenes planktonic cells and biofilm on food-contact surfaces including stainless steel and glass was systematically evaluated. The results showed that SAEW (pH of 5.09 and available chlorine concentration (ACC) of 60.33 mg/L) could kill L. monocytogenes on food-contact surfaces completely in 30 s, whose disinfection efficacy is equal to that of NaClO solutions (pH of 9.23 and ACC of 253.53 mg/L). The results showed that long exposure time and high ACC contributed to the enhancement of the disinfection efficacy of SAEW on L. monocytogenes on food-contact surfaces. Moreover, the log reduction of SAEW treatment presented an increasing tendency within the prolonging of treatment time when SAEW was used to remove the L. monocytogenes biofilm formed on stainless steel and glass surfaces, which suggested that SAEW could remove L. monocytogenes biofilm effectively and its disinfection efficacy is equal to (in case of stainless steel) or higher than (in case of glass) that of high ACC of NaClO solutions. In addition, the results of the crystal violet staining and scanning electron microscopy (SEM) also demonstrated that SAEW treatment could remove the L. monocytogenes biofilm on food-contact surfaces.

2022 ◽  
Vol 5 ◽  
pp. 4
Alicia Grace ◽  
Robert Murphy ◽  
Aoife Dillon ◽  
Diarmuid Smith ◽  
Sally-Ann Cryan ◽  

Background: Wound infections occur as sequelae to skin trauma and cause significant hospitalizations, morbidity and mortality. Skin traumas arise more frequently in those with diabetes or cardiovascular disease and in these settings, may be chronic with poorer outcomes including lower limb amputation. Treatment of chronic wound infection is challenging due to antibiotic resistance and biofilm formation by bacteria including S. aureus and P. aeruginosa, which are among the most frequent causative pathogens. Managing these challenging infections requires new molecules and modalities. Methods: We evaluated antimicrobial and anti-biofilm activity of star-shaped poly(L-lysine) (PLL) polymers against S. aureus and P. aeruginosa strains and clinical isolates recovered from wounds including diabetic foot wounds (DFW) in a Dublin Hospital in 2019. A star-shaped PLL polypeptide series, specifically G2(8)PLL20, G3(16)PLL10, G4(32)PLL5 with variation in polypeptide chain length and arm-multiplicity, were compared to a linear peptide, PLL160 with equivalent number of lysine residues. Results: All PLLs, including the linear polypeptide, were bactericidal at 1mM against S. aureus 25923 and P. aeruginosa PAO1, with log reduction in colony forming units/ml between 2.7-3.6. PLL160 demonstrated similar killing potency against 20 S. aureus and five P. aeruginosa clinical isolates from DFW, mean log reductions: 3.04 ± 0.16 and 3.96 ± 0.82 respectively after 1 hour incubation. Potent anti-biofilm activity was demonstrated against S. aureus 25923 but for clinical isolates, low to moderate loss of biofilm viability was shown using PLL160 and G3(16)PLL10 at 50 mM (S. aureus) and 200 mM (P. aeruginosa) with high inter-isolate variability. In the star-shaped architecture, antimicrobial activity was retained with incorporation of 5-mer hydrophobic amino-acid modifications to the arms of the polypeptides (series G3(16)PLL20-coPLT5, G3(16)PLL20-coPLI5, G3(16)PLL20-coPLP5). Conclusion: These polypeptides offer structural flexibility for clinical applications and have potential for further development, particularly in the setting of diabetic foot and other chronic wound infections.

2022 ◽  
Pranav Vashisht ◽  
Brahmaiah Pendyala ◽  
Ankit Patras ◽  
Vybhav Vipul Sudhir Gopisetty ◽  
Ramasamy Ravi

UV-C processing of whole milk (WM) using a designed pilot scale Dean flow system was conducted at flow rates (11.88, 23.77, and 47.55 gph), Reynolds number ranges from 2890-11562 and the Dean number (at curved region) calculated as (648-2595) to inactivate bacterial endospores and virus particles. Biodosimetry studies were conducted to quantify the reduction equivalent fluence at selected experimental conditions. Results revealed that the dose distribution improved as flow rate increases, attributed to increase in Dean effects and turbulence intensity. Microbial inactivation studies conducted at 47.55 gph showed 0.91 (stdev:0.15) and 2.14 (stdev:0.19) log reduction/ pass for B. cereus endospores and T1UV phage. Linear inactivation trend was observed against number of passes which clearly demonstrates equivalent dose delivery during each pass. Lipid peroxidation value and volatile profile did not change significantly at UV dose of 60 mJ/cm 2. Lower E EO value signifies the higher electrical efficiency of the system.


Objective: To investigate the in vitro antibacterial activity of a naturally occurring polyphenol chlorogenic acid (CGA) and compares it with formulated chlorogenic acid phytovesicles against 4 different bacterial strains; two gram positive [Staphylococcous aureus and Bacillus subtilis] and two gram negative strains [Klebsiella pneumonia and Escherichia coli]. Methods: CGA phytovesicles were developed and optimized using central composite design to improvise CGA’s physicochemical properties. Bactericidal activity was evaluated using agar diffusion, minimum inhibitory concentration (MIC) and time kill assay. The effect of pH and temperature on the antimicrobial activity was determined. Results: The optimized CGA phytovesicles showed entrapment of 96.89% with 30 times better lipophilic solubility than the plain drug. The inhibition zone sizes for CGA phytovesicle ranged from 17-25 mm as compared to 15-20 mm of plain CGA while the MIC values ranged 200-250 µg/ml as compared to 500-550 µg/ml of plain CGA. CGA phytovesicles exhibited a strong bactericidal effect at MIC with a log reduction in the range of 0.90-2.04 in Colony forming units (CFUs) at 24h for different strains as compared to 1.38-2.17 of plain CGA. Furthermore, the antibacterial effect was found to augment with increasing temperature but decreased with alkaline pH. Conclusion: Results strongly supports the hypothesis of potential use of CGA phytovesicles as a mode of drug delivery for its antibacterial use against different resistant bacteria.

2022 ◽  
Vol 11 ◽  
Shuang Fan ◽  
Meng-Zhu Shen ◽  
Xiao-Hui Zhang ◽  
Lan-Ping Xu ◽  
Yu Wang ◽  

In patients with t(8;21) acute myeloid leukemia (AML), recurrent minimal residual disease (MRD) measured by RUNX1-RUNX1T1 transcript levels can predict relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT). This study aimed to compare the efficacy of preemptive interferon (IFN)-α therapy and donor lymphocyte infusion (DLI) in patients with t(8;21) AML following allo-HSCT. We also evaluated the appropriate method for patients with different levels of RUNX1-RUNX1T1 transcripts. In this retrospective study, consecutive patients who had high-risk t(8;21) AML and received allo-HSCT were enrolled. The inclusion criteria were as follows: (1) age ≤65 years; (2) regained MRD positive following allo-HSCT. MRD positive was defined as the loss of a ≥4.5-log reduction and/or <4.5-log reduction in the RUNX1-RUNX1T1 transcripts, and high-level, intermediate-level, and low-level MRDs were, respectively, defined as <2.5-log, 2.5−3.5-log, and 3.5−4.5-log reductions in the transcripts compared with the pretreatment baseline level. Patients with positive RUNX1-RUNX1T1 could receive preemptive IFN-α therapy or DLI, which was primarily based on donor availability and the intentions of physicians and patients. The patients received recombinant human IFN-α-2b therapy by subcutaneous injection twice a week every 4 weeks. IFN-α therapy was scheduled for six cycles or until the RUNX1-RUNX1T1 transcripts were negative for at least two consecutive tests. The rates of MRD turning negative for patients with low-level, intermediate-level, and high-level RUNX1-RUNX1T1 receiving IFN-α were 87.5%, 58.1%, and 22.2%, respectively; meanwhile, for patients with intermediate-level and high-level RUNX1-RUNX1T1 receiving DLI, the rates were 50.0% and 14.3%, respectively. For patients with low-level and intermediate-level RUNX1-RUNX1T1, the probability of overall survival at 2 years was higher in the IFN-α group than in the DLI group (87.6% vs. 55.6%; p = 0.003). For patients with high levels of RUNX1-RUNX1T1, the probability of overall survival was comparable between the IFN-α and DLI groups (53.3% vs. 83.3%; p = 0.780). Therefore, patients with low-level and intermediate-level RUNX1-RUNX1T1 could benefit more from preemptive IFN-α therapy compared with DLI. Clinical outcomes were comparable between preemptive IFN-α therapy and DLI in patients with high-level RUNX1-RUNX1T1; however, they should be further improved.

2022 ◽  
Ana C Lorenzo-Leal ◽  
Selvarani Vimalanathan ◽  
Horacio Bach

The use of facial protection, including masks and respirators, has been adopted globally due to the COVID-19 pandemic. These products have been demonstrated to be effective in reducing the transmission of the virus. To determine whether or not the virus adheres to masks and respirators, we dissected four respirators and one surgical mask into layers. These individual layers were contaminated with the SARS-CoV-2 delta variant, and its release by vortexing was performed. Samples were used to infect Vero cells, and a plaque assay was used to determine to evaluate the adherence of the virus. Results showed that a cumulative log reduction of the layers reduced the load of the virus six-folds. Our study confirms the effectiveness of facial protection in reducing the transmission and or infection of the virus.

Agriculture ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 67
Thorben Schilling ◽  
Katharina Hoelzle ◽  
Werner Philipp ◽  
Ludwig E. Hoelzle

Anaerobic digestates derived from agricultural mesophilic biogas plants are mainly used as organic fertilizers. However, animal derived pathogens could persist in the anaerobic digestates (ADs) posing an epidemiological risk. The present study investigated whether storage of ADs could reduce Salmonella Typhimurium, Listeria monocytogenes, and ESBL carrying Escherichia coli and whether reduction rates are dependent on temperature and substrate. Quantified bacterial suspensions were used to inoculate ADs derived from five biogas plants using different input materials to investigate the substrate dependence of the pathogen reduction. ADs were stored over six months with four different temperature profiles each representing six consecutive months, and, thus, the four seasons. Pathogen reduction during storage was shown to be strongly dependent on the temperature but also on the type of AD. This influence was higher at low temperatures. At higher temperatures (spring and summer profiles), a 5-log reduction was achieved after twelve weeks for S. Typhimurium, after twenty weeks for E. coli (ESBL) and after twenty-four weeks for L. monocytogenes in all ADs, respectively. In contrast at lower temperatures (autumn and winter profiles), a 5-log reduction was reached after twenty-four weeks for S. Typhimurium and not reached for ESBL-E. coli and L. monocytogenes. In conclusion, storing the ADs after the biogas process improves the hygienic quality and reduce the risk of introducing pathogens to the environment, but each case should be evaluated individually considering the composition of the ADs and the storage temperatures.

Water ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 119
Suja Subhash ◽  
Pradeesh Babu ◽  
Amrutha Vijayakumar ◽  
Reshma Alookaran Suresh ◽  
Ajith Madhavan ◽  

Robust control of pathogens in sewage facilitates safe reuse of wastewater rich in valuable nutrients for potential valorization through biological means. Aspergillus niger is widely reported in bioremediation of wastewater but studies on control of enteric pathogens in sewage are very sparse. So, this study aimed at exploring the antibacterial and nematicidal activity of A. niger culture filtrate (ACF). Antibacterial activity of ACF on enteric pathogens (Klebsiella pneumoniae, Pseudomonas aeruginosa, Vibrio cholerae, Salmonella enterica, Shigella dysenteriae, Escherichia coli, Staphylococcus aureus, Klebsiella variicola) was determined by spectrophotometric growth analysis, resazurin based viability assay and biofilm formation assay. ACF showed inhibition against all enteric pathogens except Pseudomonas aeruginosa. Nematicidal studies on Caenorhabditis elegans showed 85% egg hatch inhibition and 52% mortality of L1 larvae. Sewage treatment with ACF at 1:1 (v/v) showed 2–3 log reduction in coliforms, Klebsiella, Shigella, Salmonella, S. aureus and Vibrio except Pseudomonas, indicating significant alteration of complex microbial dynamics in wastewater. Application of ACF can potentially be used as a robust biocontrol strategy against infectious microbes in wastewater and subsequent valorization by cultivating beneficial Pseudomonas.

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