Combining bacteriophage and vancomycin is efficacious against MRSA biofilm-like aggregates formed in synovial fluid.

Background: Biofilm formation is a major clinical challenge contributing to treatment failure of periprosthetic joint infection (PJI). Lytic bacteriophages (phages) can target biofilm associated bacteria at localized sites of infection. The aim of this study is to investigate whether combination therapy of phage and vancomycin is capable of clearing Staphylococcus aureus biofilm-like aggregates formed in human synovial fluid. Methods: In this study, S. aureus BP043, a PJI clinical isolate was utilized. This strain is a methicillin-resistant S. aureus (MRSA) biofilm-former. Phage Remus, known to infect S. aureus, was selected for the treatment protocol. BP043 was grown as aggregates in human synovial fluid. The characterization of S. aureus aggregates was assessed for structure and size using scanning electron microscopy (SEM) and flow cytometry, respectively. Moreover, the formed aggregates were subsequently treated in vitro with: (a) phage Remus [∼108 plaque-forming units (PFU)/ml], (b) vancomycin (500 µg/ml), or (c) phage Remus (∼108 PFU/ml) followed by vancomycin (500 µg/ml), for 48 h. Bacterial survival was quantified by enumeration [colony-forming units (CFU)/ml]. The efficacy of phage and vancomycin against BP043 aggregates was assessed in vivo as individual treatments and in combination. The in vivo model utilized Galleria mellonella larvae which were infected with BP043 aggregates pre-formed in synovial fluid. Results: Scanning electron microscopy (SEM) images and flow cytometry data demonstrated the ability of human synovial fluid to promote formation of S. aureus aggregates. Treatment with Remus resulted in significant reduction in viable S. aureus residing within the synovial fluid aggregates compared to the aggregates that did not receive Remus (p < 0.0001). Remus was more efficient in eliminating viable bacteria within the aggregates compared to vancomycin (p < 0.0001). Combination treatment of Remus followed by vancomycin was more efficacious in reducing bacterial load compared to using either Remus or vancomycin alone (p = 0.0023, p < 0.0001, respectively). When tested in vivo, this combination treatment also resulted in the highest survival rate (37%) 96 h post-treatment, compared to untreated larvae (3%; p < 0.0001). Conclusion: We demonstrate that combining phage Remus and vancomycin led to synergistic interaction against MRSA biofilm-like aggregates in vitro and in vivo.

Combining povidone-iodine with vancomycin can be beneficial in reducing early biofilm formation of methicillin-resistant Staphylococcus aureus and methicillin-sensitive S. aureus on titanium surface.

There is controversial clinical evidence regarding the added antibacterial benefit of locally administering antiseptic solutions or antibiotics to the infected joint space. The objectives of this in vitro study were to test the efficacy of povidone-iodine (PVP-I) and vancomycin in treating premature and developed Staphylococcus aureus biofilms grown on titanium implant surfaces. PVP-I and vancomycin were used to treat immature and developed biofilms formed by two clinical strains of S. aureus (BP043-MRSA, PB011-MSSA). S. aureus strains were grown as immature (3 h-old) or developed (24 h-old) biofilm. These biofilms were grown on titanium plasma sprayed discs. The treatment regimens tested were: 0.8% PVP-I, 500 µg/ml vancomycin as well as a combination of vancomycin and PVP-I. PVP-I was tested at 3 min, as per current clinical practice, versus 1 min treatment times. In addition, the cytotoxicity of the PVP-I and vancomycin was tested using fresh skeletal muscle tissue cores harvested from the rat's abdominal muscles using alamarBlue assay. The combination of PVP-I (3 min) and vancomycin (24 h.) showed synergistic interaction and the best efficacy against immature biofilms formed by both clinical strains. This degree of eradication was statistically significant compared to the untreated control, p < .0001. However, this combination therapy had limited efficiency against developed biofilms. Also, PVP-I alone was more effective when exposure time was 3 min instead of 1 min against immature biofilm for MRSA, p = .02, and MSSA, p = .01. PVP-I and vancomycin were not effective against developed biofilm regardless of exposure time. Also, combining PVP-I and vancomycin was not cytotoxic to muscle tissue. Combining PVP-I with vancomycin is superior in reducing viable S. aureus cells in immature biofilms grown on titanium surface without causing significant cytotoxicity to muscle tissue. Exposure times and biofilm maturity play a role in dictating the efficacy of using local antiseptics and antibiotics to treat biofilms on implant surfaces.

Rapid detection of bacteria using gold nanoparticles in SERS with three different capping agents: Thioglucose, polyvinylpyrrolidone, and citrate.

The increase in outbreaks of emerging and re-emerging bacterial infections over the last few decades calls for their rapid detection and treatment. Surface-enhanced Raman spectroscopy (SERS) is a technique that can be applied to develop fast screening systems for bacterial presence in biological samples. Optimizing the capping agents in nanoparticle synthesis is important because capping agents are responsible for controlling the morphological features and chemical properties of the nanoparticles that are essential for SERS. To the best of our knowledge, this paper is the first to study the application of gold nanoparticles capped with thioglucose and polyvinylpyrrolidone (PVP) in SERS detection of bacteria as an alternative to the citrate-capped gold nanoparticles that are often used in SERS detection of bacteria. Three different species of bacteria were used in this study: Cutibacterium acnes, Escherichia coli and Staphylococcus aureus (methicillin-sensitive and methicillin-resistant). This study demonstrates that the thioglucose, citrate both show good contribution in bacterial species identification and the thioglucose shows the best among the three capping agents in two types of S. aureus identification. Moreover, although PVP showed high Raman peaks in the SERS spectrum for each type of bacteria, it showed least contribution in identifying species and strains due to its low efficacy in producing responses from different nucleic acid components in the bacteria cells.

Chromatographic methods for the determination of a broad spectrum of UV filters in swimming pool water.

This paper describes an analytical approach based on solid-phase extraction (SPE) followed by analysis using liquid and gas chromatography coupled to mass spectrometry detectors for a determination of 18 organic UV filters from water samples. Extraction method parameters were optimized: 250 ml of water sample loaded on Chromabond C18 cartridges after adjustment to pH 4 and then eluted with acetonitrile. The mobile phase and the parameters of the mass spectrometer, as well as those of the ionization source, were tested to enhance detection sensitivity. During method validation, the extracted target compounds showed good recoveries (> 68%) with acceptable values in terms of repeatability (RSDr) and reproducibility (RSDR), where relative standard deviations values were lower than 20%. The validated method was applied to 10 water samples collected from different swimming pools located in Lebanon from which eight UV filters among the eighteen targets compounds were detected at concentrations ranged between 1 and 2526 µg L-1. The most detected compounds were padimate-O (OD-PABA) and octocrylene (OCR). This study represents the first available data on the occurrence of UV filter residues in Lebanese swimming pool opening hence future perspectives and insights to evaluate their degradation by-products and their toxicity on human health and marine ecosystem.

2021 Frank Stinchfield Award: A novel cemented hip hemiarthroplasty infection model with real-time in vivo imaging in rats : an animal study.

AIMS: The aims of this study were to develop an in vivo model of periprosthetic joint infection (PJI) in cemented hip hemiarthroplasty, and to monitor infection and biofilm formation in real-time. METHODS: Sprague-Dawley rats underwent cemented hip hemiarthroplasty via the posterior approach with pre- and postoperative gait assessments. Infection with Staphylococcus aureus Xen36 was monitored with in vivo photoluminescent imaging in real-time. Pre- and postoperative gait analyses were performed and compared. Postmortem micro (m) CT was used to assess implant integration; field emission scanning electron microscopy (FE-SEM) was used to assess biofilm formation on prosthetic surfaces. RESULTS: All animals tolerated surgery well, with preservation of gait mechanics and weightbearing in control individuals. Postoperative in vivo imaging demonstrated predictable evolution of infection with logarithmic signal decay coinciding with abscess formation. Postmortem mCT qualitative volumetric analysis showed high contact area and both cement-bone and cement-implant interdigitation. FE-SEM revealed biofilm formation on the prosthetic head. CONCLUSION: This study demonstrates the utility of a new, high-fidelity model of in vivo PJI using cemented hip hemiarthroplasty in rats. Inoculation with bioluminescent bacteria allows for non-invasive, real-time monitoring of infection. Cite this article: Bone Joint J 2021;103-B(7 Supple B):9-16.

Aluminum exposure from food in the population of Lebanon.

Widely used for a variety of applications, levels of dietary aluminum (Al) have seen a perpetual rise in Lebanon, leading to noticeable effects upon the human body. This study aims to estimate the rates of Al contaminated food consumption and quantify the Al present in different dietary matrices, revealing the major contributors to Al exposure for the Lebanese population. A cross-sectional study was conducted using a customized, self-reported Electronic Food Frequency Questionnaire (E-FFQ) using Curve®, targeting individuals between the ages of 18 and 64 from different Lebanese regions, distributed proportionally. The selection of food was based upon the results of the French EAT2 study. Al levels in food were analyzed using Flame Atomic Absorption Spectrometry (FAAS) after acid digestion. The E-FFQ was completed by 167 respondents. Data analysis was performed on SPSS version 25. Additionally, 97 food items were studied in 2018. Al levels had a mean of 3.56 ± 2.08 mg/kg (ranging from 0.14 to 9.37). The highest Al levels were found in vegetables, followed by sauces and condiments, candies, and ready meals. The Provisional Tolerable Weekly Intake (PTWI) of Al was set at 0.50 mg/kg body weight (60 Kg/person). Al mean Daily Dietary Exposure (DDE) was estimated to be 4341.18 µg/day, with the highest food exposure coming from lettuce, soft drinks, ice cream and tea. Al ingestion rates for the adult Lebanese population does not exceed the international established thresholds of tolerable intake (1 mg/kg/week). National recommendation should be developed to control the presence of metal for food safety purposes.

Biological control of Erwinia mallotivora, the causal agent of papaya dieback disease by indigenous seed-borne endophytic lactic acid bacteria consortium.

Dieback disease caused by Erwinia mallotivora is a major threat to papaya plantation in Malaysia. The current study was conducted to evaluate the potential of endophytic lactic acid bacteria (LAB) isolated from papaya seeds for disease suppression of papaya dieback. Two hundred and thirty isolates were screened against E. mallotivora BT-MARDI, and the inhibitory activity of the isolates against the pathogen was ranging from 11.7-23.7 mm inhibition zones. The synergistic experiments revealed that combination of W. cibaria PPKSD19 and Lactococcus lactis subsp. lactis PPSSD39 increased antibacterial activity against the pathogen. The antibacterial activity was partially due to the production of bacteriocin-like inhibitory substances (BLIS). The nursery experiment confirmed that the application of bacterial consortium W. cibaria PPKSD19 and L. lactis subsp. lactis PPSSD39 significantly reduced disease severity to 19% and increased biocontrol efficacy to 69% of infected papaya plants after 18 days of treatment. This study showed that W. cibaria PPKSD19 and L. lactis subsp. lactis PPSSD39 are potential candidate as biocontrol agents against papaya dieback disease.

Bacterial survival in whole blood depends on plasma sensitivity and resistance to neutrophil killing.

BACKGROUND: Whole blood (WB) is held at room temperature for not more than 24 hours before blood component manufacturing. The ability of several culture collection, skin-derived, and transfusion-related bacteria to survive in WB stored at 22 ± 2°C for 24 hours was investigated in this study. STUDY DESIGN AND METHODS: Twenty-one bacteria of the species Staphylococcus epidermidis, Staphylococcus aureus, Staphylococcus capitis, Streptococcus agalactiae, Serratia liquefaciens, Serratia marcescens, Klebsiella pneumoniae, Escherichia coli, and Yersinia enterocolitica were inoculated into 7-mL aliquots of WB at a concentration of 500 colony-forming units (CFU)/mL. Spiked WB was stored aerobically at 22 ± 2°C, and bacterial viability and growth were monitored at 3, 8, and 24 hours during WB storage. Bacteria that showed decreased viability during WB incubation were further characterized for their sensitivity to plasma factors and neutrophil killing. RESULTS: There were three different scenarios for bacterial behavior during the hold of WB at 22 ± 2°C. Five bacteria proliferated (p < 0.03), 11 remained viable or showed low proliferation, and a third group of five bacteria had decreased or lost viability (p < 0.01). Three of the latter five bacteria were plasma-sensitive while the other two were plasma-resistant but susceptible to neutrophil killing (p = 0.01). CONCLUSIONS: The bactericidal activity of WB can be the result of plasma sensitivity or neutrophil killing. Bacteria with a starting inoculum of 500 CFU/mL, and able to resist WB immune factors, can proliferate to clinically significant levels posing a potential safety risk to transfusion patients. Results of this pilot study should be validated under standard WB collection and storage conditions.

The peptidoglycan and biofilm matrix of Staphylococcus epidermidis undergo structural changes when exposed to human platelets.

Staphylococcus epidermidis is a bacterium frequently isolated from contaminated platelet concentrates (PCs), a blood product used to treat bleeding disorders in transfusion patients. PCs offer an accidental niche for colonization of S. epidermidis by forming biofilms and thus avoiding clearance by immune factors present in this milieu. Using biochemical and microscopy techniques, we investigated the structural changes of the peptidoglycan (PG) and the biofilm matrix of S. epidermidis biofilms formed in whole-blood derived PCs compared to biofilms grown in glucose-supplemented trypticase soy broth (TSBg). Both, the PG and the biofilm matrix are primary mechanisms of defense against environmental stress. Here we show that in PCs, the S. epidermidis biofilm matrix is mainly of a proteinaceous nature with extracellular DNA, in contrast to the predominant polysaccharide nature of the biofilm matrix formed in TSBg cultures. PG profile studies demonstrated that the PG of biofilm cells remodels during PC storage displaying fewer muropeptides variants than those observed in TSBg. The PG muropeptides contain two chemical modifications (amidation and O-acetylation) previously associated with resistance to antimicrobial agents by other staphylococci. Our study highlights two key structural features of S. epidermidis that are remodeled when exposed to human platelets and could be used as targets to reduce septic transfusions events.

New Innovations in the Treatment of PJI and Biofilms-Clinical and Preclinical Topics.

PURPOSE OF REVIEW: Periprosthetic joint infection (PJI) is a devastating complication after total joint replacement. A main source for antibiotic tolerance and treatment failure is bacterial production of biofilm-a resilient barrier against antibiotics, immune system, and mechanical debridement. The purpose of this review is to explore some novel approaches to treat PJI and biofilm-related infections. RECENT FINDINGS: Innovative treatment strategies of bacterial and biofilm infections revolve around (a) augmenting current therapies, such as improving the delivery and efficiency of conventional antibiotics and enhancing the efficacy of antiseptics and (b) administrating completely new therapeutic modalities, such as using immunotherapy, nanoparticles, lytic bacteriophages, photodynamic therapy, novel antibiotics, and antimicrobial peptides. Several promising treatment strategies for PJI are available to be tested further. The next requirement for most of the novel treatments is reproducing their effects in clinically representative animal models of PJI against clinical isolates of relevant bacteria.

Comparative characterisation of the biofilm-production abilities of Staphylococcus epidermidis isolated from human skin and platelet concentrates.

PURPOSE: Staphylococcus epidermidis is the predominant contaminant of platelet concentrates (PCs), a blood product used to treat patients with platelet deficiencies. This microorganism is able to form surface-attached aggregates (biofilms) in human skin. Herein, the abundance of S. epidermidis biofilm-producers in contaminated PCs compared to skin isolates was explored. Furthermore, the potential positive selection of S. epidermidis biofilm-producers during the blood donation process and PC manufacturing was investigated. METHODOLOGY: Twenty-four S. epidermidis isolates obtained from contaminated PCs and 48 S. epidermidis isolates obtained from the venipuncture area of human volunteers were compared for their ability to form biofilms in laboratory media and in PCs using a semi quantitative crystal violet assay. Also, the presence of the biofilm-associated icaA and icaD genes was assessed by PCR-amplification.Results/Key findings.Biofilm production in laboratory media showed a higher number of S. epidermidis biofilm-producers in the skin-derived group (43.7 %) compared to the PC-derived isolates (25 %). However, all skin and PC isolates formed biofilms in PCs. The prevalence of ica-positive biofilm-producer isolates was similar in PC and skin isolates (16.6 and 18.8 %, respectively). In contrast, the abundance of ica-negative biofilm-producers was lower in PC isolates compared to skin isolates (8.3 vs 25 %, respectively). CONCLUSION: Positive selection of S. epidermidis biofilm-producers during blood donation and PC manufacturing was not observed. Interestingly, ica-negative biofilm-producers seem to be negatively affected by skin disinfection, blood processing and PC storage. Furthermore, this study shows that S. epidermidis adopts a biofilm-forming phenotype in PCs regardless of its genetic background or origin.

Does Treatment Order Matter? Investigating the Ability of Bacteriophage to Augment Antibiotic Activity against Staphylococcus aureus Biofilms.

The inability to effectively treat biofilm-related infections is a major clinical challenge. This has been attributed to the heightened antibiotic tolerance conferred to bacterial cells embedded within biofilms. Lytic bacteriophages (phages) have evolved to effectively infect and eradicate biofilm-associated cells. The current study was designed to investigate the ability of phage treatment to enhance the activity of antibiotics against biofilm-forming Staphylococcus aureus. The biofilm positive S. aureus strain ATCC 35556, the lytic S. aureus phage SATA-8505, and five antibiotics (cefazolin, vancomycin, dicloxacillin, tetracycline, and linezolid), used to treat S. aureus infections, were tested in this study. The ability of the SATA-8505 phage to augment the effect of these antibiotics against biofilm-associated S. aureus cells was assessed by exposing them to one of the five following treatment strategies: (i) antibiotics alone, (ii) phage alone, (iii) a combination of the two treatments simultaneously, (iv) staggered exposure to the phage followed by antibiotics, and (v) staggered exposure to antibiotics followed by exposure to phage. The effect of each treatment strategy on biofilm cells was assessed by enumerating viable bacterial cells. The results demonstrate that the treatment of biofilms with either SATA-8505, antibiotics, or both simultaneously resulted in minimal reduction of viable biofilm-associated cells. However, a significant reduction [up to 3 log colony forming unit (CFU)/mL] was observed when the phage treatment preceded antibiotics. This effect was most pronounced with vancomycin and cefazolin which exhibited synergistic interactions with SATA-8505, particularly at lower antibiotic concentrations. This in vitro study provides proof of principle for the ability of phages to augment the activity of antibiotics against S. aureus biofilms. Our results also demonstrate that therapeutic outcomes can be influenced by the sequence in which these therapeutic agents are administered, and the nature of their interactions. Further investigation into the interactions between lytic phages and antibiotics against various biofilm-forming organisms is important to direct future clinical translation of efficacious antibiotic-phage combination therapeutic strategies.

Current review-The rise of bacteriophage as a unique therapeutic platform in treating peri-prosthetic joint infections.

Peri-prosthetic joint infection (PJI) is one of the most serious and dreaded complications after total joint replacement (TJR). Due to an aging population and the constant rise in demand for TJR, the incidence of PJI is also increasing. Successful treatment of PJI is challenging and is associated with high failure rates. One of the main causes for treatment failure is bacterial biofilm formation on implant surfaces and the adherence of biofilm bacteria on tissue and bone next to the implant. Biofilms are protective shields to bacterial cells and possess many unique properties that leads to antibiotic resistance. New therapeutic platforms are currently being explored to breakdown biofilm matrix in order to enhance the efficacy of antibiotics. Bacteriophages (phages) is one of these unique therapeutic platforms that can degrade biofilms as well as target the killing of bacterial cells. Preclinical studies of biofilm-mediated infections have demonstrated the ability of phage to eradicate biofilms and clear infections by working synergistically with antibiotics. There is strong preclinical evidence that phage can reduce the concentration of antibiotics required to treat an infection. These findings support a promising role for phages as a future clinical adjunct to antibiotics. In addition, phage therapy can be personalized to target a specific bacterial strain. Clinical studies using phage therapy are limited in Western literature; but phase I studies have established good safety profile with no adverse outcomes reported. In order to translate phage therapy to treat PJI in clinics, further preclinical testing is still required to study optimal delivery methods as well as the interaction between phage and the immune system in vivo. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1051-1060, 2018.

Enhancing blood donor skin disinfection using natural oils.

BACKGROUND: Effective donor skin disinfection is essential in preventing bacterial contamination of blood components with skin flora bacteria like Staphylococcus epidermidis. Cell aggregates of S. epidermidis (biofilms) are found on the skin and are resistant to the commonly used donor skin disinfectants chlorhexidine-gluconate and isopropyl alcohol. It has been demonstrated that essential oils synergistically enhance the antibacterial activity of chlorhexidine-gluconate. The objective of this study was to test plant-extracted essential oils in combination with chlorhexidine-gluconate or chlorhexidine-gluconate plus isopropyl alcohol for their ability to eliminate S. epidermidis biofilms. STUDY DESIGN AND METHODS: The composition of oils extracted from Artemisia herba-alba, Lavandula multifida, Origanum marjoram, Rosmarinus officinalis, and Thymus capitatus was analyzed using gas chromatography-mass spectrometry. A rabbit model was used to assess skin irritation caused by the oils. In addition, the anti-biofilm activity of the oils used alone or in combination with chlorhexidine-gluconate or chlorhexidine-gluconate plus isopropyl alcohol was tested against S. epidermidis biofilms. RESULTS: Essential oil concentrations 10%, 20%, and 30% were chosen for anti-biofilm assays, because skin irritation was observed at concentrations greater than 30%. All oils except for O. marjoram had anti-biofilm activity at these three concentrations. L. multifida synergistically enhanced the anti-biofilm activity of chlorhexidine-gluconate and resulted in the highest anti-biofilm activity observed when combined with chlorhexidine-gluconate plus isopropyl alcohol. Gas chromatography-mass spectrometry revealed that the main component contributing to the activity of L. multifida oil was a natural terpene alcohol called linalool. CONCLUSION: The anti-biofilm activity of chlorhexidine-gluconate plus isopropyl alcohol can be greatly enhanced by L. multifida oil or linalool. Therefore, these components could potentially be used to improve blood donor skin disinfection.

Septic transfusion case caused by a platelet pool with visible clotting due to contamination with Staphylococcus aureus.

BACKGROUND: Contamination of platelet concentrates (PCs) with Staphylococcus aureus is one of the most significant ongoing transfusion safety risks in developed countries. CASE REPORT: This report describes a transfusion reaction in an elderly patient diagnosed with acute myeloid leukemia, transfused with a 4-day-old buffy coat PC through a central venous catheter. The transfusion was interrupted when a large fibrous clot in the PC obstructed infusion pump flow. Shortly afterward, a red blood cell (RBC) unit transfusion started. After septic symptoms were developed, the RBC transfusion was also interrupted. While the RBC unit tested negative for bacterial contamination, the PC and the patient samples were found to be contaminated with a S. aureus strain that exhibited the same phenotypic and genome sequencing profiles. The isolated S. aureus forms biofilms and produces the superantigen enterotoxin-like U, which was detected in a sample of the transfused PCs. The patient received posttransfusion antibiotic treatment and had her original central line removed and replaced. DISCUSSION: As the implicated PC had been tested for bacterial contamination during routine screening yielding negative results, this is a false-negative transfusion sepsis case. Using a point-of-care test could have prevented the transfusion reaction. This report highlights the increasing incidence of S. aureus as a major PC contaminant with grave clinical implications. Importantly, S. aureus is able to interact with platelet components resulting in visible changes in PCs. CONCLUSION: Visual inspection of blood components before transfusion is an essential safety practice to interdict the transfusion of bacterially contaminated units.

Validation of sterility testing of cord blood: challenges and results.

BACKGROUND: Sterility testing for cord blood (CB) products is mandatory to prevent transplantation-transmitted microbial infections. Here, the automated BacT/ALERT (bioMérieux) culture system was validated to detect microbial contamination in CB units processed at the Canadian National Public Cord Blood Bank. STUDY DESIGN AND METHODS: A three-phase validation was developed. CB units were prepared with pentastarch (Phases 1 and 2) or hetastarch (Phase 3). In Phase 1, CB was spiked with approximately 100 colony-forming units/mL of Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis, Bacteroides fragilis, and Candida albicans. Plasma (8 mL) and buffy coat (BC; 0.5 and 8 mL) were inoculated into culture bottles. In Phases 2 and 3, a mix of red blood cells (RBCs) and plasma (4 mL each) was used as the inoculant. In Phase 3, Aspergillus brasiliensis was added as a test organism and microbial concentrations in the by-product RBCs and plasma were determined. The BC fractions were cryopreserved and tested 3 months later. RESULTS: In Phase 1, bacteria failed to grow in CB units containing antibiotics. Thus, antibiotic-free units were used for the other phases. C. albicans was not always captured in plasma, but using a mix of RBCs and plasma, all organisms were detected. The use of pentastarch or hetastarch did not affect microbial recovery. C. albicans and A. brasiliensis were preferentially recovered in RBCs and BC. Cryopreservation did not affect microbial survival during CB processing. CONCLUSIONS: A mix of plasma and RBCs is appropriate for CB sterility testing. Interestingly, fungi preferentially segregate to cellular fractions. The clinical significance of the bactericidal /or bacteriostatic effect of antibiotics in CB merits further investigation.

Evaluation of sorption capacity of antibiotics and antibacterial properties of a cyclodextrin-polymer functionalized hydroxyapatite-coated titanium hip prosthesis.

Infection still present as one of common complications after total hip replacement (∼2.5%), which may cause serious outcomes. For preventing such risk, loading antibiotics onto implants for increasing local drug concentration at targeted sites could be a solution. This study aims at modifying the surface of hydroxyapatite (HA) coated titanium hip implant material (Ti-HA) with polymer of cyclodextrin (polyCD) for loading antibiotics, to achieve a sustained local drug delivery. Two widely applied antibiotics (tobramycin and rifampicin) in orthopedic surgery were loaded alone or in combination. The drug adsorption isotherm, drug release kinetics and drug's efficacy were thoroughly investigated. The results proved that polyCD coating significantly improved the affinity of both drugs to Ti-HA surface, while the mechanism of drug-polyCD interaction varies from the nature of drug, courtesy of the structural complex of polyCD. The advantage of dual-drug loading was highlighted by its strong efficacy against both Staphylococcus aureus and Enterobacter cloacae, which overcomes the limitation of mono-drug loading for an effective treatment against both bacterial strains. The prolonged antibacterial activity of antibiotic loaded Ti-HA-polyCD samples confirmed that polyCD could be a promising drug-delivery system, for sustained antibiotics release or other potential applications e.g., antimitotic agent release.

Biofilm-forming skin microflora bacteria are resistant to the bactericidal action of disinfectants used during blood donation.

BACKGROUND: A one-step skin disinfection method containing 2% chlorhexidine-gluconate (CHG) and 70% isopropyl alcohol (IPA) is currently used by blood suppliers worldwide. Reports of bacterially contaminated platelet concentrates (PCs) indicate that skin disinfection is not fully effective. Approximately 20% of skin microflora exist as surface-attached aggregates (biofilms), known for displaying increased resistance to disinfectants. This study was aimed at determining whether skin microflora biofilm-positive Staphylococcus epidermidis and Staphylococcus capitis are resistant to CHG and/or IPA. STUDY DESIGN AND METHODS: Free-floating cells and mono or dual (1 : 1 ratio) biofilms of S. epidermidis and S. capitis were exposed to CHG, IPA, or CHG/IPA for 30 seconds, simulating skin disinfection practices. Residual viable cells were quantified by colony counting. Morphology of disinfectant-treated S. epidermidis biofilms was examined by scanning electron microscopy. Treated S. epidermidis and S. capitis biofilms were inoculated into PCs and bacterial concentrations were determined on Days 0 and 5 of storage. RESULTS: Treatment of staphylococcal biofilm cells with all disinfectants caused cell damage and significant reduction in viability, with CHG/IPA being the most effective. However, biofilms were significantly more resistant to treatment than free-floating cells. Disinfectant-treated S. epidermidis proliferated better in PCs than S. capitis, especially when grown as monospecies biofilms. CONCLUSION: Although CHG/IPA is effective in reducing the viability of S. epidermidis and S. capitis biofilms, these organisms are not completely eliminated. Furthermore, disinfectant-treated staphylococcal biofilms multiply well in PCs. These results demonstrate that the biofilm-forming capability of the skin microflora reduces the bactericidal efficiency of blood donor skin disinfectants.

Mussel inspired coating of a biocompatible cyclodextrin based polymer onto CoCr vascular stents.

During the past decade, drug-eluting stents (DES) have been widely used for the treatment of occlusive coronary artery diseases. They are supposed to reduce the incidence of early in-stent restenosis by the elution of highly hydrophobic antiproliferative drugs. Nevertheless, the absence of long-term activity of these devices is responsible for late acute thrombosis probably due to the delayed re-endothelialization of the arterial wall over the bare metallic stent struts. Thus, a new generation of DES with a sustained release of therapeutic agents is required to improve long-term results of these devices. In this article, we report an original functionalization of CoCr vascular devices with a hydrophilic, biocompatible and biodegradable cyclodextrins based polymer which acts as a reservoir for lipophilic drugs allowing the sustained release of antiproliferative drugs. In this setting, polydopamine (PDA), a strong adhesive biopolymer, was applied as a first coating layer onto the surface of the metallic CoCr device in order to promote the strong anchorage of a cyclodextrin polymer. This polymer was generated "in situ" from the methylated cyclodextrins and citric acid as a cross-linking agent through a polycondensation reaction. After optimization of the grafting process, the amount of cyclodextrin polymer coated onto the CoCr device was quantified by colorimetric titrations and the resulting film was characterized by scanning electron microscopy (SEM) investigations. The cytocompatibility of the resulting coated film was assessed by cell proliferation and vitality tests. Finally, the ability of this coated device to act as a drug-eluting system was evaluated with paclitaxel, a strong hydrophobic antiproliferative drug, a reference drug used in current vascular drug-eluting stents.