In vivo analysis of a first-in-class tri-alkyl norspermidine-biaryl antibiotic in an active release coating to reduce the risk of implant-related infection

Determining Which Combinatorial Combat-Relevant Factors Contribute to Heterotopic Ossification Formation in an Ovine Model

Traumatic heterotopic ossification (HO) is frequently observed in Service Members following combat-related trauma. Estimates suggest that ~65% of wounded warriors who suffer limb loss or major extremity trauma will experience some type of HO formation. The development of HO delays rehabilitation and can prevent the use of a prosthetic. To date there are limited data to suggest a standard mechanism for preventing HO. This may be due to inadequate animal models not producing a similar bone structure as human HO. We recently showed that traumatic HO growth is possible in an ovine model. Within that study, we demonstrated that 65% of sheep developed a human-relevant hybrid traumatic HO bone structure after being exposed to a combination of seven combat-relevant factors. Although HO formed, we did not determine which traumatic factor contributed most. Therefore, in this study, we performed individual and various combinations of surgical/traumatic factors to determine their individual contribution to HO growth. Outcomes showed that the presence of mature biofilm stimulated a large region of bone growth, while bone trauma resulted in a localized bone response as indicated by jagged bone at the linea aspera. However, it was not until the combinatory factors were included that an HO structure similar to that of humans formed more readily in 60% of the sheep. In conclusion, data suggested that traumatic HO growth can develop following various traumatic factors, but a combination of known instigators yields higher frequency size and consistency of ectopic bone.

Current Progress and Future Perspectives in Contact and Releasing-Type Antimicrobial Coatings of Orthopaedic Implants: A Systematic Review Analysis Emanated from In Vitro and In Vivo Models

Background: Despite the expanding use of orthopedic devices and the application of strict pre- and postoperative protocols, the elimination of postoperative implant-related infections remains a challenge. Objectives: To identify and assess the in vitro and in vivo properties of antimicrobial-, silver- and iodine-based implants, as well as to present novel approaches to surface modifications of orthopedic implants. Methods: A systematic computer-based review on the development of these implants, on PubMed and Web of Science databases, was carried out according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Results: Overall, 31 in vitro and 40 in vivo entries were evaluated. Regarding the in vitro studies, antimicrobial-based coatings were assessed in 12 entries, silver-based coatings in 10, iodine-based in 1, and novel-applied coating technologies in 8 entries. Regarding the in vivo studies, antimicrobial coatings were evaluated in 23 entries, silver-coated implants in 12, and iodine-coated in 1 entry, respectively. The application of novel coatings was studied in the rest of the cases (4). Antimicrobial efficacy was examined using different bacterial strains, and osseointegration ability and biocompatibility were examined in eukaryotic cells and different animal models, including rats, rabbits, and sheep. Conclusions: Assessment of both in vivo and in vitro studies revealed a wide antimicrobial spectrum of the coated implants, related to reduced bacterial growth, inhibition of biofilm formation, and unaffected or enhanced osseointegration, emphasizing the importance of the application of surface modification techniques as an alternative for the treatment of orthopedic implant infections in the clinical settings.

The potential of sheep in preclinical models for bone infection research - A systematic review

Background

Reliable animal models are critical for preclinical research and should closely mimic the disease. With respect to route of infection, pathogenic agent, disease progression, clinical signs, and histopathological changes. Sheep have similar bone micro- and macrostructure as well as comparable biomechanical characteristics to humans. Their use in bone research is established, however their use in bone infection research is limited. This systematic review will summarise the key features of the available bone infection models using sheep, providing a reference for further development, validation, and application.

Method

This systematic review was designed according to the PRISMA guidelines and registered with PROSPERO. Quality was assessed using SYRICLE's risk of bias tool adapted for animal studies. PubMed, MEDLINE, Web of Science and EMBASE were searched until March 2022.1921 articles were screened by two independent reviewers, and 25 were included for analysis.

Results

Models have been developed in nine different breeds. Staphylococcus aureus was used in the majority of models, typically inoculating 108 colony forming units in tibial or femoral cortical defects. Infection was established with either planktonic or biofilm adherent bacteria, with or without foreign material implanted. Most studies used both radiological and microbiological analyses to confirm osteomyelitis.

Conclusions

There is convincing evidence supporting the use of sheep in bone infection models of clinical disease. The majority of sheep studied demonstrated convincing osteomyelitis and tolerated the infection with minimal complications. Furthermore, the advantages of comparable biology and biomechanics may increase the success for translating in vivo results to successful therapies.

The Translational potential of this article

In the realm of preclinical research, the translation to viable clinical therapies is often perilous, and the quest for reliable and representative animal models remains paramount. This systematic review accentuates the largely untapped potential of sheep as large animal models, especially in bone infection research. The anatomical and biomechanical parallels between sheep and human bone structures position sheep as an invaluable asset for studying osteomyelitis and periprosthetic joint infection. This comprehensive exploration of the literature demonstrates the robustness and translational promise of these models. Furthermore, this article underscores the potential applicability for sheep in developing effective therapeutic strategies for human bone infections.

Ex vivo comparison of V.A.C.® Granufoam Silver™ and V.A.C.® Granufoam™ loaded with a first-in-class bis-dialkylnorspermidine-terphenyl antibiofilm agent

Implementation of negative pressure wound therapy (NPWT) as a standard of care has proven efficacious in reducing both the healing time and likelihood of nosocomial infection among pressure ulcers and traumatic, combat-related injuries. However, current formulations may not target or dramatically reduce bacterial biofilm burden following therapy. The purpose of this study was to determine the antibiofilm efficacy of an open-cell polyurethane (PU) foam (V.A.C.® Granufoam™) loaded with a first-in-class compound (CZ-01179) as the active release agent integrated via lyophilized hydrogel scaffolding. An ex vivo porcine excision wound model was designed to perform antibiofilm efficacy testing in the presence of NPWT. PU foam samples loaded with a 10.0% w/w formulation of CZ-01179 and 0.5% hyaluronic acid were prepared and tested against current standards of care: V.A.C.® Granufoam Silver™ and V.A.C.® Granufoam™. We observed statistically significant reduction of methicillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter baumannii biofilms with the CZ-01179 antibiofilm foam in comparison to current standard of care foams. These findings motivate further development of an antibiofilm PU foam loaded with CZ-01179.

Physical Approaches to Prevent and Treat Bacterial Biofilm

Prosthetic joint infection (PJI) presents several clinical challenges. This is in large part due to the formation of biofilm which can make infection eradication exceedingly difficult. Following an extensive literature search, this review surveys a variety of non-pharmacological methods of preventing and/or treating biofilm within the body and how they could be utilized in the treatment of PJI. Special attention has been paid to physical strategies such as heat, light, sound, and electromagnetic energy, and their uses in biofilm treatment. Though these methods are still under study, they offer a potential means to reduce the morbidity and financial burden related to multiple stage revisions and prolonged systemic antibiotic courses that make up the current gold standard in PJI treatment. Given that these options are still in the early stages of development and offer their own strengths and weaknesses, this review offers an assessment of each method, the progress made on each, and allows for comparison of methods with discussion of future challenges to their implementation in a clinical setting.

Black-Phosphorus-Nanosheet-Reinforced Coating of Implants for Sequential Biofilm Ablation and Bone Fracture Healing Acceleration

Incurable implant-related infection may cause catastrophic consequences due to the existence of a biofilm that resists the infiltration of host immune cells and antibiotics. Innovative approaches inspired by nanomedicine, e.g., engineering innovative multifunctional bionic coating systems on the surface of implants, are becoming increasingly attractive. Herein, 2D black phosphorus nanosheets (BPs) were loaded onto a hydroxyapatite (HA)-coated metal implant to construct a BPs@HA composite coating. With its photothermal conversion effect and in situ biomineralization, the BPs@HA coating shows excellent performances in ablating the bacterial biofilm and accelerating fracture healing, which were verified through both in vitro and in vivo studies. Moreover, differentially expressed genes of bone formation and bone mesenchymal stem cells (BMSCs) regulated by the BPs@HA coating were identified using absolute quantitative transcriptome sequencing followed by the screening of gene differential expressions. A functional enrichment analysis reveals that the expression of core markers related to BMSC differentiation and bone formation could be effectively regulated by BPs through a metabolism-related pathway. This work not only illustrates the great potential in clinical application of the BPs@HA composite coating to eliminate bacteria and accelerate bone fracture healing but also contributes to an understanding of the underlying molecular mechanism of osteogenesis physiological function regulation based on an analysis of absolute quantitative transcriptome sequencing.

Lytic Bacteriophage as a Biomaterial to Prevent Biofilm Formation and Promote Neural Growth

BACKGROUND

Although non-lytic filamentous bacteriophages have been made into biomaterial to guide tissue growth, they had limited ability to prevent bacterial infection. In this work a lytic bacteriophage was used to make an antibacterial biomaterial for neural tissue repair.

METHODS

Lytic phages were chemically bound to the surface of a chitosan film through glutaraldehyde crosslinking. After the chemical reaction, the contact angle of the sample surface and the remaining lytic potential of the phages were measured. The numbers of bacteria on the samples were measured and examined under scanning electron microscopy. Transmission electron microscopy (TEM) was used to observe the phages and phage-infected bacteria. A neuroblast cell line was cultured on the samples to evaluate the sample's biocompatibility.

RESULTS

The phages conjugated to the chitosan film preserved their lytic potential and reduced 68% of bacterial growth on the sample surface at 120 min (p < 0.001). The phage-linked surface had a significantly higher contact angle than that of the control chitosan (p < 0.05). After 120 min a bacterial biofilm appeared on the control chitosan, while the phage-linked sample effectively prevented biofilm formation. The TEM images demonstrated that the phage attached and lysed the bacteria on the phage-linked sample at 120 min. The phage-linked sample significantly promoted the neuroblast cell attachment (p < 0.05) and proliferation (p < 0.01). The neuroblast on the phage-linked sample demonstrated more cell extensions after day 1.

CONCLUSION

The purified lytic phages were proven to be a highly bioactive nanomaterial. The phage-chitosan composite material not only promoted neural cell proliferation but also effectively prevent bacterial growth, a major cause of implant failure and removal.

Antimicrobial coating strategy to prevent orthopaedic device-related infections: recent advances and future perspectives

The rapid development of multidrug-resistant (MDR) bacteria and biofilm-related infections (BRIs) has urgently called for new strategies to combat severe orthopaedic device-related infections (ODRIs). Antimicrobial coating has emerged as a promising strategy in halting the incidence of ODRIs and treating ODRIs in long term. With the advancement of material science and biotechnology, numerous antimicrobial coatings have been reported in literature, showing superior antimicrobial and osteogenic functions. This review has specifically discussed the currently developed antimicrobial coatings in the perspective of drug release from the coating system, focusing on their realization of controlled and on demand antimicrobial agents release, as well as multi-functionality. Acknowledging the multidisciplinary nature of antimicrobial coating, the conceptual design, the deposition method and the therapeutic effect of the antimicrobial coatings have been described in detail and discussed critically. Particularly, the challenges and opportunities on the way toward the clinical translation of antimicrobial coatings have been highlighted.

Biofilm Growth on Simulated Fracture Fixation Plates Using a Customized CDC Biofilm Reactor for a Sheep Model of Biofilm-Related Infection

Most animal models of infection utilize planktonic bacteria as initial inocula. However, this may not accurately mimic scenarios where bacteria in the biofilm phenotype contaminate a site at the point of injury. We developed a modified CDC biofilm reactor in which biofilms can be grown on the surface of simulated fracture fixation plates. Multiple reactor runs were performed and demonstrated that monomicrobial biofilms of a clinical strain of methicillin-resistant Staphylococcus aureus, S. aureus ATCC 6538, and Pseudomonas aeruginosa ATCC 27853 consistently developed on fixation plates. We also identified a method by which to successfully grow polymicrobial biofilms of S. aureus ATCC 6538 and P. aeruginosa ATCC 27853 on fixation plates. This customized reactor can be used to grow biofilms on simulated fracture fixation plates that can be inoculated in animal models of biofilm implant-related infection that, for example, mimic open fracture scenarios. The reactor provides a method for growing biofilms that can be used as initial inocula and potentially improve the testing and development of antibiofilm technologies.

Antibiofilm potential of a negative pressure wound therapy foam loaded with a first-in-class tri-alkyl norspermidine-biaryl antibiotic

Negative-pressure wound therapy (NPWT) is commonly utilized to treat traumatic injuries sustained on the modern battlefield. However, NPWT has failed to decrease the incidence of deep tissue infections experienced by Wounded Warriors, despite attempts to integrate common antimicrobials, like Ag+ nanoparticles, into the wound dressing. The purpose of this study was to incorporate a unique antibiofilm compound (CZ-01179) into the polyurethane matrix of NPWT foam via lyophilized hydrogel scaffolding. Foam samples with 2.5%, 5.0%, and 10.0% w/w CZ-01179 were produced and antibiofilm efficacy was compared to the current standards of care: V.A.C.® GRANUFOAM SILVER™ and V.A.C.® GRANUFOAM™. Gravimetric analysis and elution kinetics testing confirmed that this loading technique was both repeatable and controllable. Furthermore, zone of inhibition and antibiofilm efficacy testing showed that foam loaded with CZ-01179 had significantly increased activity against planktonic and biofilm phenotypes of methicillin-resistant Staphylococcus aureus and Acinetobacter baumannii compared to the clinical standards. These findings motivate additional ex vivo and in vivo work with NPWT foam loaded with CZ-01179 with the overall objective of reducing NPWT-associated infections that complicate battlefield-related and other wounds.

Recent Advances in the Evaluation of Antimicrobial Materials for Resolution of Orthopedic Implant-Associated Infections In Vivo

While orthopedic implant-associated infections are rare, revision surgeries resulting from infections incur considerable healthcare costs and represent a substantial research area clinically, in academia, and in industry. In recent years, there have been numerous advances in the development of antimicrobial strategies for the prevention and treatment of orthopedic implant-associated infections which offer promise to improve the limitations of existing delivery systems through local and controlled release of antimicrobial agents. Prior to translation to in vivo orthopedic implant-associated infection models, the properties (e.g., degradation, antimicrobial activity, biocompatibility) of the antimicrobial materials can be evaluated in subcutaneous implant in vivo models. The antimicrobial materials are then incorporated into in vivo implant models to evaluate the efficacy of using the material to prevent or treat implant-associated infections. Recent technological advances such as 3D-printing, bacterial genomic sequencing, and real-time in vivo imaging of infection and inflammation have contributed to the development of preclinical implant-associated infection models that more effectively recapitulate the clinical presentation of infections and improve the evaluation of antimicrobial materials. This Review highlights the advantages and limitations of antimicrobial materials used in conjunction with orthopedic implants for the prevention and treatment of orthopedic implant-associated infections and discusses how these materials are evaluated in preclinical in vivo models. This analysis serves as a resource for biomaterial researchers in the selection of an appropriate orthopedic implant-associated infection preclinical model to evaluate novel antimicrobial materials.

Assessing the safety of an epiphyseal plate biopsy in a translational lamb model

The literature demonstrates that obtaining a biopsy of the physis may be beneficial for diagnostic purposes. A small biopsy of the epiphyseal plate may allow for earlier detection of certain conditions and be used to monitor the healing of diseased and/or damaged physes. However, due to the fear of a growth arrest in a growing child, biopsies are not currently performed. In this study, we investigated the effects of a biopsy of the epiphyseal plate in 3-month-old lambs. A total of 4.2 mm biopsy samples were captured in the proximal tibiae and distal femora physes. The lambs were monitored 12- and 24-week post-biopsy. Computed tomography (CT) and micro-CT scans were obtained to determine if any angular deformities occurred, while scanning electron microscope (SEM) and histological analysis were utilized to assess the bone response due to the biopsy. The contralateral limbs served as unaltered controls for direct comparison within each lamb. The data demonstrated no signs of angular deformities following a 4.2 mm biopsy of the physis. Bone growth/elongation was confirmed by CT, SEM, and fluorochrome analyses and indicated that the lambs were in fact immature and still growing at the time of the biopsy. Clinical Significance: This investigation demonstrated that a small biopsy of the epiphyseal plate can be obtained safely without the cause of growth arrest and angular deformities. The ability to precisely diagnose, treat, and/or monitor at-risk children at an earlier timepoint by way of a biopsy sample could be an important advancement in regard to researching diseased and/or damaged physes.

Fitting pieces into the puzzle: The impact of titanium-based dental implant surface modifications on bacterial accumulation and polymicrobial infections

Polymicrobial infection is the main cause of dental implant failure. Although numerous studies have reported the ability of titanium (Ti) surface modifications to inhibit microbial adhesion and biofilm accumulation, the majority of solutions for the utilization of Ti antibacterial surfaces have been testedin in vitro and animal models, with only a few developed surfaces progressing into clinical research. Motivated by this huge gap, we critically reviewed the scientific literature on the existing antibacterial Ti surfaces to help understand these surfaces' impact on the "puzzle" of undesirable dental implant-related infections. This manuscript comprises three main sections: (i) a narrative review on topics related to oral biofilm formation, bacterial-implant surface interactions, and on how implant-surface modifications can influence microbial accumulation; (ii) a critical evidence-based review to summarize pre-clinical and clinical studies in an attempt to "fit pieces into the puzzle" to unveil the best way to reduce microbial loads and control polymicrobial infection around dental implants showed by the current in vivo evidence; and (iii) discussion and recommendations for future research testing emerging antibacterial implant surfaces, connecting basic science and the requirements for future clinical translation. The findings of the present review suggest no consensus regarding the best available Ti surface to reduce bacterial colonization on dental implants. Smart release or on-demand activation surface coatings are a "new piece of the puzzle", which may be the most effective alternative for reducing microbial colonization on Ti surfaces, and future studies should focus on these technologies.

Developing a combat-relevant translatable large animal model of heterotopic ossification

Heterotopic ossification (HO) refers to ectopic bone formation, typically in residual limbs following trauma and injury. A review of injuries from Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF) indicated that approximately 70% of war wounds involved the musculoskeletal system, largely in part from the use of improvised explosive devices (IED) and rocket-propelled grenades (RPG). HO is reported to occur in approximately 63%–65% of wounded warriors from OIF and OEF. Symptomatic HO may delay rehabilitation regimens since it often requires modifications to prosthetic limb componentry and socket size. There is limited evidence indicating a mechanism for preventing HO. This may be due to inadequate models, which do not produce HO bone structure that is morphologically similar to HO samples obtained from wounded warfighters injured in theatre. We hypothesized that using a high-power blast of air (shockwave) and simulated battlefield trauma (i.e. bone damage, tourniquet, bacteria, negative pressure wound therapy) in a large animal model, HO would form and have similar morphology to ectopic bone observed in clinical samples. Initial radiographic and micro-computed tomography (CT) data demonstrated ectopic bone growth in sheep 24 weeks post-procedure. Advanced histological and backscatter electron (BSE) analyses showed that 5 out of 8 (63%) sheep produced HO with similar morphology to clinical samples. We conclude that not all ectopic bone observed by radiograph or micro-CT in animal models is HO. Advanced histological and BSE analyses may improve confirmation of HO presence and morphology, which we demonstrated can be produced in a large animal model.

Titanium implant coating based on dopamine-functionalized sulphated hyaluronic acid: in vivo assessment of biocompatibility and antibacterial efficacy

The number of total knee and/or hip replacements are expected to exceed 5 million a year by 2030; the incidence of biofilm-associated complications can vary from 1% in primary implants to 5.6% in case of revision. The purpose of this study was to test the ability of sHA-DA, a partially sulphated hyaluronic acid (sHA) functionalized with a dopamine (DA) moiety, to prevent acute bacterial growth in an in vivo model of an intra-operatively highly contaminated implant. Previously, in vitro studies showed that the DA moiety guarantees good performance as binding agent for titanium surface adhesion, while the negatively charged sHA has both a high efficiency in electrostatic binding of positively charged antibiotics, and bone regenerative effects. The in vitro testing also highlighted the effectiveness of the sHA-DA system in inhibiting bacterial spreading through a sustained release of the antibiotic payload from the implant coating. In this study the chemical stability of the sHA-DA to β-ray sterilization was demonstrated, based on evaluation by NMR, SEC-TDA Omnisec and HPLC-MS analysis, thus supporting the approach of terminal sterilization of the coated implant with no loss of efficacy. Furthermore, an in vivo study in rabbits was performed according to UNI EN ISO 10993-6 to assess the histocompatibility of titanium nails pre-coated with sHA-DA. The implants, placed in the femoral medullary cavity and harvested after 12 weeks, proved to be histocompatible and to allow bone growth in adhesion to the metal surface. Finally, an in vivo model of bacterial contamination was set up by injecting 1 mL of bacterial suspension containing 10⁴ or 10⁶ CFU of methicillin-resistant Staphylococcus aureus (MRSA) into the femoral medullary cavity of 30 rabbits. Titanium nails either uncoated or pre-coated with sHA-DA and loaded directly by the surgeon with 5% vancomycin were implanted in the surgical site. After 1 week, only the animals treated with pre-coated nails did not show the presence of systemic or local bacterial infection, as confirmed by microbiology and histology (Smeltzer score). Further insights into the animal model setup are crucial, however the results obtained suggest that the system can be effective in preventing the onset of the bacterial infective process.

Histological Analysis of a Retrieved Porous Tantalum Total Ankle Replacement: A Case Report

CASE

We present a case report documenting the retrieval and histological analysis of a porous tantalum (P-Ta) total ankle replacement (TAR) from a 50-year-old woman after a below-knee transtibial amputation. This rare opportunity to examine an intact TAR may help to better understand the implant-bone relationship because it would be in situ.

CONCLUSION

In this case study, we demonstrate bone ingrowth to the first layer of the P-Ta and organized trabecular orientation, suggesting that equal bone load was achieved on the base and the rails in both components using a transfibular surgical approach.

Antibacterial and anti-inflammatory ultrahigh molecular weight polyethylene/tea polyphenol blends for artificial joint applications

Periprosthetic joint infection (PJI) is one of the main causes for the failure of joint arthroplasty. In view of the limited clinical effect of oral/injectable antibiotics and the drug resistance problem, there is a pressing need to develop antibacterial implants with therapeutic antimicrobial properties. In this work, we prepared a highly antibacterial ultrahigh molecular weight polyethylene (UHMWPE) implant by incorporating tea polyphenols. The presence of tea polyphenols not only improved the oxidation stability of irradiated UHMWPE, but also gave it the desirable antibacterial property. The potent antibacterial activity was attributed to the tea polyphenols that produced excess intracellular reactive oxygen species and destroyed the bacterial membrane structure. The tea polyphenol-blended UHMWPE had no biological toxicity to human adipose-derived stem cells and effectively reduced bacteria-induced inflammation in vivo. These results indicate that tea polyphenol-blended UHMWPE is promising for joint replacement prostheses with multifunctionality to meet patient satisfaction.

Protecting the skin-implant interface with transcutaneous silver-coated skin-and-bone-integrated pylon in pig and rabbit dorsum models

Implant-associated soft tissue infections at the skin-implant interface represent the most frequent complications in reconstructive surgery and lead to implant failures and revisions. Titanium implants with deep porosity, called skin-and-bone-integrated-pylons (SBIP), allow for skin ingrowth in the morphologically natural direction, thus restoring a reliable dermal barrier and reducing the risk of infection. Silver coating of the SBIP implant surface using physical vapor deposition technique offers the possibility of preventing biofilm formation and exerting a direct antimicrobial effect during the wound healing phase. In vivo studies employing pig and rabbit dorsum models for assessment of skin ingrowth into the pores of the pylon demonstrated the safety of transcutaneous implantation of the SBIP system. No postoperative complications were reported at the end of the follow-up period of 6 months. Histological analysis proved skin ingrowth in the minipig model without signs of silver toxicity. Analysis of silver release (using energy dispersive X-ray spectroscopy) in the model of intramedullary-inserted silver-coated SBIP in New Zealand rabbits demonstrated trace amounts of silver after 3 months of in-bone implantation. In conclusion, selected temporary silver coating of the SBIP implant surface is powerful at preventing the periprosthetic infections without imparing skin ingrowth and can be considered for clinical application.

A tailored positively-charged hydrophobic surface reduces the risk of implant associated infections

Implant-associated infections is one of the most challenging post-operative complications in bone-related implantations. To tackle this clinical issue, we developed a low-cost and durable surface coating for medical grade titanium implants that uses positively charged silane molecules. The in vitro antimicrobial tests revealed that the titanium surface coated with (3-aminopropyl) triethoxysilane, which has the appropriate length of hydrophobic alkyl chain and positive charged amino group, suppressed more than 90% of the initial bacterial adhesion of S. aureus, P. aeruginosa, and E. coli after 30 min of incubation. In terms of growth inhibitory rate, the treated surface was able to reduce 75.7% ± 11.9% of bacterial growth after a 24-hour culturing, thereby exhibiting superior anti-biofilm formation in the late stage. When implanted into the rat model infected by S. aureus, the treated surface eliminated the implant-associated infection through the mechanism of inhibition of bacterial adhesion on the implant surface. Additionally, the treated surface was highly compatible with mammalian cells. In general, our design demonstrated its potential for human clinical trials as a low-cost and effective antibacterial strategy to minimize post-operative implant-related bacterial infection.

In vivo efficacy of a unique first-in-class antibiofilm antibiotic for biofilm-related wound infections caused by Acinetobacter baumannii

Wounds complicated by biofilms challenge even the best clinical care and can delay a return to duty for service members. A major component of treatment in wounded warriors includes infected wound management. Yet, all antibiotic therapy options have been optimized against planktonic bacteria, leaving an important gap in biofilm-related wound care. We tested the efficacy of a unique compound (CZ-01179) specifically synthesized to eradicate biofilms. CZ-01179 was formulated as the active agent in a hydrogel, and tested in vitro and in vivo in a pig excision wound model for its ability to treat and prevent biofilm-related wound infection caused by Acinetobacter baumannii. Data indicated that compared to a clinical standard—silver sulfadiazine—CZ-01179 was much more effective at eradicating biofilms of A. baumannii in vitro and up to 6 days faster at eradicating biofilms in vivo. CZ-01179 belongs to a broader class of newly-synthesized antibiofilm agents (referred to as CZ compounds) with reduced risk of resistance development, specific efficacy against biofilms, and promising formulation potential for clinical applications. Given its broad spectrum and biofilm-specific nature, CZ-01179 gel may be a promising agent to increase the pipeline of products to treat and prevent biofilm-related wound infections.