Bacteria antibiotic resistance: New challenges and opportunities for implant-associated orthopedic infections

Fabrication of a ZnO/Polydopamine/ε-Polylysine Coating with Good Corrosion Resistance and a Joint Antibacterial Pathway on the Surface of Medical Stainless Steel

Medical stainless steel (SS) is a widely used alloy in orthopedic and dental implant applications. However, SS can cause local corrosion in the body, which may affect cell proliferation and differentiation, and is prone to related bacterial infection. Therefore, surface modification is required to improve the corrosion resistance and antibacterial performance of SS to extend its service life. To achieve this goal, a new type of composite coating was established on the surface of SS. First, zinc oxide (ZnO) nanoparticles were deposited on the surface of SS by electrochemical deposition. Then, polydopamine (PDA) was formed through the self-polymerization of dopamine. Finally, the Michael addition reaction between ε-polylysine (ε-PL) and PDA was used to chemically graft a cationic antimicrobial peptide (AMP), namely, ε-PL, constructing a corrosion-resistant and antibacterial ZnO/PDA/ε-PL coating on the surface of the SS (SZP/ε-PL). The results indicated that the obtained composite coating could significantly improve the corrosion resistance of SS because of the introduction of ZnO. After being irradiated with near-infrared (NIR) light (wavelength: 1064 nm, power: 1 W/cm2) for 8 min, the temperature of SZP/ε-PL increased from 22.4 to 57.8 °C. Moreover, there was no significant temperature decay after four cycles, which indicated the good photothermal performance and stability of SZP/ε-PL owing to the function of PDA. Combining photothermal sterilization and AMP contact sterilization, the antibacterial rates of SZP/ε-PL against Escherichia coli and Staphylococcus aureus both reached nearly 100%. In addition, SZP/ε-PL has excellent blood compatibility. With the above advantages, SZP/ε-PL was expected to become a safe and efficient implant material.

Extended oral antibiotic prophylaxis and PJI-free survivorship after primary total knee arthroplasty

INTRODUCTION

Recent evidence has emerged supporting the use of extended oral antibiotic (EOA) prophylaxis after primary total knee replacement (TKA) to reduce periprosthetic joint infection (PJI) in high-risk patients. However, much of the evidence stems from single-institution series with limited sample sizes. This study aimed to explore the impact of EOA on complications and infection-free survivorship in a large cohort of patients after primary TKA.

METHODS

A large national database was used to identify patients undergoing primary TKA from 2015 to 2022. Patients receiving 7-14 days of EOA were identified. Propensity-score matching, based on patient comorbidities, was used to match patients who received EOA and to control patients who did not. Three cohorts were created: any-risk, high-risk, and standard-risk. Complications at 90-days were assessed with univariate analysis and survivorship free of PJI to 2 years was analyzed with the Kaplan-Meier method and cox regression.

RESULTS

We identified 5,701 patients who received EOA: 3,628 (64%) with high-risk comorbidities and 2,073 (36%) standard risk. There were no significant reduction in hazard of PJI at 90-days (any-risk: HR: 1.65, 95% CI: 0.90-3.04, P = 0.11; high-risk: HR: 1.37, 95% CI: 0.69-2.70, P = 0.4; standard-risk: HR: 1.51, 95% CI: 0.53-4.26, P = 0.4), 1 year (P > 0.07), or 2 years (any-risk: HR: 1.42, 95% CI: 0.98-2.05, P = 0.065; high-risk: HR: 1.14, 95% CI: 0.76-1.73, P = 0.5; standard-risk: HR: 1.51, 95% CI: 0.76-2.98, P = 0.2) with EOA administration.

DISCUSSION

EOA prophylaxis was not associated with improved PJI-free survivorship at any measured time point following primary TKA in either high-risk or standard-risk risk patients. Given the observed widespread use of EOA, our study highlights the need for further investigation to delineate what specific populations may benefit from EOA prophylaxis.

Inactivation of antibiotic resistant bacteria by ruthenium-doped carbon dots capable of photodynamic generation of intracellular and extracellular reactive oxygen species

Wound infections caused by methicillin-resistant Staphylococcus aureus (MRSA) present a significant challenge to wound healing. This has motivated the development of novel antibiotic-free agents. In this study, ruthenium-doped carbon dots (Ru-CDs) with photodynamic antibacterial activity were synthesized to treat MRSA-infected skin wounds. The Ru-CDs were prepared via a hydrothermal method using Ru-Aphen as the nitrogen source and citric acid as the carbon source, resulting in uniform spherical nanoparticles with an average size of 2.7 ± 0.8 nm. Singlet oxygen generation was observed when the Ru-CDs were exposed to light. In vitro experiments showed concentration- and light-dependent antibacterial activity of the Ru-CDs against MRSA, with 99.9 % bacterial reduction when treated with 100 μg/mL Ru-CDs under light for 10 min. A significant level of intracellular ROS was observed, and microscopy confirmed bacterial membrane disruption. Biocompatibility tests showed no significant toxicity, and in vivo studies on rabbit wound models demonstrated effective antibacterial activity under light conditions and enhanced wound healing compared to controls. The results collectively highlight the potential of Ru-CDs as an antibiotic-free agent for treating antibiotic resistant bacterial infections through photodynamic generation of extracellular ROS and induction of intracellular ROS.

How Dutch orthopedic healthcare professionals perceive antibiotic resistance: A mixed-methods application of the mental model approach

Healthcare professionals must act to curb antibiotic resistance (ABR), one of today's greatest threats to global health. This study applied the mental model approach to understanding perceptions of ABR among different Dutch orthopedic healthcare professionals. The expert model (step 1) was based on evidence-based ABR information and expert interviews (n = 3). This model prompted the step 2 questionnaire to inquire about perceived causes, consequences, and actions related to ABR (open-ended, n = 12). In the step 3 questionnaire (Likert-scales, n = 55), participants rated the impact of causes of ABR, the likelihood and severity of consequences of ABR, and the effectiveness of actions against ABR. Step 3 showed that no specific causes, consequences, or actions are perceived to strongly outweigh the others. Dutch orthopedic healthcare professionals perceive the causes of ABR to be mostly external, the consequences of ABR to be abstract and the most effective actions against ABR to be performed by others.

Unveiling Berberine analogues as potential inhibitors of Escherichia coli FtsZ through machine learning molecular docking and molecular dynamics approach

The bacterial cell division protein FtsZ, a crucial GTPase, plays a vital role in the formation of the contractile Z-ring, which is essential for bacterial cytokinesis. Consequently, inhibiting FtsZ could prevent the formation of proto-filaments and interfere with the cell division machinery. The remarkable conservation of FtsZ across diverse bacterial species makes it a promising drug target for combating drug resistance. In the present study, 1072 berberine analogues were screened for favorable pharmacokinetic properties. A total of 60 compounds that fulfilled the drug-likeliness criteria and were found to be non-toxic were selected for virtual screening against Escherichia coli FtsZ protein (PDB ID: 8GZY). Molecular docking revealed a strong binding affinity of ZINC000524729297 (- 8.73 kcal/mol) and ZINC000604405393 (and - 8.55 kcal/mol) with FtsZ by strong intermolecular hydrogen bonds and hydrophobic interactions. Subsequently, the docking profiles were validated through a 500 ns MD simulation and MMPBSA analysis of the FtsZ-ligand complexes. The analysis revealed the FtsZ- ZINC524729297 and FtsZ-ZINC000604405393 complexes had the lowest root-mean-square deviation with lowest binding energy and enhanced conformational stability in a dynamic environment. These findings suggest that ZINC524729297 and ZINC000604405393 are the potent lead compound that targets FtsZ and requires further experimental validation.

Antimicrobial Silicon Rubber Crosslinked with Bornyl-Siloxane

Silicone rubber (SiR) has a wide range of medical applications, but it lacks antimicrobial properties, leading to potential infection issues with related implants or medical devices. Most studies focus on adding anti-bacterial agents or surface modification, which usually result in composites with anti-bacterial properties, rather than synthesizing SiR with intrinsically antimicrobial performances. To tackle this issue, a double substituted bornyl-siloxane crosslinker (BC) is designed. This crosslinker can react with hydroxy-terminated polydimethylsiloxane (PDMS) at room temperature to yield SiR with borneol side groups. The process is simple without using additional solvents. Antimicrobial assay on SiR cured with different ratios of BC/PDMS showed that 20 wt.% BC cross-linked network exhibited outstanding anti-bacterial adhesion (Escherichia coli 99.4%, Staphylococcus aureus 97.3%) performance and long-lasting anti-mold (Aspergillus niger over 99% for 30 days) adhesion properties. Moreover, the subcutaneous implantation model in mice demonstrated its excellent anti-infection, biocompatibility and safety. Therefore, this material is promising for widespread adoption in the medical field, especially in silicon-based products or coatings.

A Novel Isotropic Optical Fiber: Antimicrobial Effect of Blue Light on Drug Resistant Organisms

Drug-resistant organisms (DROs) necessitate the development of new therapies. Antimicrobial blue light (ABL) is a promising option, utilizing photoexcitation of endogenous bacterial components to generate reactive oxygen species, leading to bacterial death. The aim of this study is to investigate the effects of a novel isotropic optical fiber under in-vitro conditions on multidrug-resistant gram-negative Pseudomonas aeruginosa (MDR-Pa) and methicillin-resistant Staphylococcus aureus (MRSA). Time-to-kill assays were conducted in tubes containing 10 mL of 0.9% NaCl solution with an inoculum of 1 × 10⁵ CFU/mL for MDR-Pa or MRSA. The experiments were repeated at least three times per strain. Experimental tubes had either one (low power, LP) or two (high power, HP) optical fibers delivering five ABL wavelengths (405, 415, 435, 450, and 475 nm) over 60 min. Control tubes lacked optical fibers. Samples were taken at 0, 10, 20, 30, and 60 min, streaked on agar, and incubated to determine CFU/mL. Bactericidal reduction was defined as a ≥ 99.9% (≥ 3 log10) reduction in CFU/mL. One-way ANOVA were conducted. The novel isotropic optical fiber was able to exhibit bactericidal effects for MDR-Pa only under HP-ABL with a log10CFU/mL ± SD difference of -3.71 ± 0.01 at 60 min (p = 0.03). Conversely, the optical fiber exhibited bactericidal effects on MRSA under both LP-ABL and HP-ABL with a log10CFU/mL±SD difference of -3.73 ± 0.08 at 60 min (p = 0.03) and -3.07 ± 0.28 at 20 min (p = 0.02), respectively. The isotropic optical fiber demonstrated bactericidal effects on MRSA and MDR-Pa in in-vitro studies and shows potential as a therapeutic option for DROs.

Methicillin-sensitive Staphylococcus aureus lineages contribute towards poor patient outcomes in orthopaedic device-related infections

Staphylococci are the most common cause of orthopaedic device-related infections (ODRIs), with Staphylococcus aureus responsible for a third or more of cases. This prospective clinical and laboratory study investigated the association of genomic and phenotypic variation with treatment outcomes in ODRI isolates. Eighty-six invasive S. aureus isolates were collected from patients with ODRI, and clinical outcome was assessed after a follow-up examination of 24 months. Each patient was then considered to have been 'cured' or 'not cured' based on predefined clinical criteria. Whole-genome sequencing and molecular characterization identified isolates belonging to globally circulating community- and hospital-acquired lineages. Most isolates were phenotypically susceptible to methicillin and lacked the staphylococcal cassette chromosome mec cassette [methicillin-susceptible S. aureus (MSSA); 94%] but contained several virulence genes, including toxins and biofilm genes. Whilst recognizing the role of the host immune response, we identified genetic variance, which could be associated with the infection severity or clinical outcome. Whilst this and several other studies reinforce the role antibiotic resistance [e.g. methicillin-resistant S. aureus (MRSA) infection] has on treatment failure, it is important not to overlook MSSA that can cause equally destructive infections and lead to poor patient outcomes.

Assessing the Effects of Surface-Stabilized Zero-Valent Iron Nanoparticles on Diverse Bacteria Species Using Complementary Statistical Models

Nanoparticles are proposed as alternatives to traditional antimicrobial agents. By manipulating a nanoparticle's core and surface coating, antimicrobial effects against various microbial populations can be customized, known as the "designer effect". However, the antimicrobial properties of nanoparticle core-coating combinations are understudied; little research exists on their effects on diverse bacteria. The antimicrobial effects of surface-stabilized zero-valent iron nanoparticles (FeNPs) are particularly interesting due to their stability in water and ferromagnetic properties. This study explores the impact of FeNPs coated with three surface coatings on six diverse bacterial species. The FeNPs were synthesized and capped with L-ascorbic acid (AA), cetyltrimethylammonium bromide (CTAB), or polyvinylpyrrolidone (PVP) using a bottom-up approach. Zone of inhibition (ZOI) values, assessed through the disc diffusion assay, indicated that AA-FeNPs and CTAB-FeNPs displayed the most potent antibacterial activity. Bacteria inhibition results ranked from most sensitive to least sensitive are the following: Bacillus nealsonii > Escherichia coli > Staphylococcus aureus > Delftia acidovorans > Chryseobacterium sp. > Sphingobacterium multivorum. Comparisons using ordinal regression and generalized linear mixed models revealed significant differences in bacterial responses to the different coatings and nanoparticle concentrations. The statistical model results are in agreement, thus increasing confidence in these conclusions. This study supports the feasibility of the "designer nanoparticle" concept and offers a framework for future research.

The efficacy of the bacteriocinogenic Enterococcus faecalis 14 in the control of induced necrotic enteritis in broilers

PURPOSE

To demonstrate the efficacy of the bacteriocinogenic Enterococcus faecalis 14 (E. faecalis 14) in the control of induced necrotic enteritis (NE) in broilers.

METHODS

Six groups of 504 broilers consisting of an infected untreated control (IUC) group, an infected and amoxicillin treated control (ITC) group, and groups receiving prophylactically (2 groups) or therapeutically (2 groups) E. faecalis 14 or its Δbac mutant were used. All groups were challenged with Clostridium perfringens 56 to induce NE. To predispose the boilers to develop subclinical NE, a high protein grower diet containing 15 % fishmeal and a coccidial inoculum were administered.

RESULTS

NE lesions were observed on D26 in all groups except ITC and those receiving prophylactically and therapeutically E. faecalis 14. On D27, only ITC and the group prophylactically treated with E. faecalis 14 (T03) were without lesions. Average body weight and daily weight gain remained lower in the treated groups compared to the ITC group, but there was a clear improvement in the period between D21 to D27, especially in the group prophylactically treated with E. faecalis 14. Specifically, the daily weight gain (DWG) in this period for group T03, was second highest after the group ITC. Metataxonomic analyses showed a positive effect of E. faecalis 14 in maintaining the diversity and richness of the intestinal microbiota, in contrast to ITC group and other conditions.

CONCLUSIONS

The results of this in vivo study demonstrated the efficacy of the prophylactic administration of the bacteriocinogenic E. faecalis 14 in preventing of the NE lesions caused by C. perfringens.

Isolation and characterization of new lytic bacteriophage PSA-KC1 against Pseudomonas aeruginosa isolates from cystic fibrosis patients

A novel lytic bacteriophage, PSA-KC1, was isolated from wastewater. In this study, the whole genome of the bacteriophage PSA-KC1 was analyzed, and its lytic properties were assessed. PSA-KC1 has a linear double-stranded DNA genome with a total length of 43,237 base pairs and a GC content of 53.6%. In total, 65 genes were predicted, 46 of which were assigned functions as structural proteins involved in genome replication, packaging or phage lysis. PSA-KC1 belongs to the genus Septimatrevirus under the Caudoviricetes class. The aim of this study was to investigate the efficacy of the lytic bacteriophage PSA-KC1 and compare it with that of the Pyophage phage cocktail on 25 multi drug resistant (MDR) Pseudomonas aeruginosa strains isolated from sputum samples of cystic fibrosis patients. Seventeen of these strains were susceptible (68%) to the PSA-KC1 lytic phage we isolated, whereas eight clinical strains were resistant. However, 22 (88%) of the P. aeruginosa strains were susceptible to the Pyophage cocktail, and three (12%) were resistant to the Phage cocktail. At the end of our study, a new lytic phage active against multidrug-resistant P. aeruginosa strains from CF patients was isolated, and its genome was characterized. Since the PSA-KC1 phage does not contain virulence factors, toxins or integrase genes, it can be expected to be a therapeutic candidate with the potential to be used safely in phage therapy.

Anti-Bacterial Properties and Hemocompatibility of Alkali Treated Nano-Structured Micro-Porous Titanium Surfaces

Titanium and its alloys have been the material of choice for orthopedic implants due to their excellent physical properties as well as biocompatibility. However, titanium is not able to integrate with bone due to the mismatch of mechanical properties. Additionally, bone has a micro-nano hierarchy, which is absent on titanium's surface. A potential solution to the former is to make the surfaces porous to bring the mechanical properties closer to that of the bone, and a solution for the latter is to fabricate nanostructures. In this study, micro-porous titanium surfaces were hydrothermally treated using an alkali medium to fabricate nanostructures on the existing micro-porosity of the surface. The surface properties were evaluated using scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and nanoindentation. The anti-bacterial properties of the surfaces were evaluated against Gram-positive and Gram-negative bacteria using fluorescence microscopy and scanning electron microscopy. Blood clotting is shown to improve the surface-to-bone integration; hence, whole blood clotting and platelet adhesion and activation were evaluated using a whole blood clotting assay, fluorescence microscopy, and scanning electron microscopy. The results indicate that nanostructured micro-porous titanium surfaces display significantly enhanced anti-bacterial properties as well as equivalent blood clotting characteristics compared to non-porous titanium surfaces.

Synergistic antibacterial drug elution from UHMWPE for load-bearing implants

Total joint replacement is a successful procedure for restoring the patient's musculoskeletal mobility and quality of life, but it carries the risk of severe peri-prosthetic joint infections (PJI) and is accompanied by post-operative pain. Cocktails of multiple drugs are often used for prevention/treatment of PJI and for addressing pain. Local drug delivery systems are promising for improving the outcome of the treatment and decreasing the side effects of systemic drugs. To this end, the ultra-high molecular weight polyethylene (UHMWPE) bearing surface of the joint implant is here proposed as a platform for simultaneous release of multiple therapeutics. The combined use of non-antibiotic drugs and antibiotics, and their incorporation into UHMWPE allows to obtain novel antibacterial implant materials. The combined elution of analgesics and antibiotics from UHMWPE is found to be synergistically effective in eradicating Staphylococcus aureus, as the non-antibiotic compound significantly enhances the antibacterial activity of the antibiotic. The drug properties and the employed method for their incorporation into UHMWPE are found to dictate the morphology, thus the mechanical properties of the resulting material. By adopting various fabrication methods, novel formulations showing an enhanced antibacterial activity and outstanding mechanical properties are here proposed to amplify the functionality of polymeric implant materials.

A multi-functional oxidative konjac glucomannan/ε-poly-l-lysine hydrogel with antibacterial, haemostatic, and chronic diabetic wound-treating properties

A chronic diabetic wound, one of the most severe complications of diabetes, has a high incidence and causes great pain to patients, threatening their lives. In this paper, oxidative konjac glucomannan (OKGM) was reacted with ε-poly-l-lysine (EPL) through the dynamic Schiff's base reaction to make a multi-functional hydrogel. This hydrogel had excellent mechanical properties, injectability, self-healing ability, adhesivity and cytocompatibility. The outstanding haemostatic property was also expressed in rat liver incision, liver injury and tail truncation models. In addition, this hydrogel exhibited unique antibacterial ability against the Gram-positive Staphylococcus aureus (S. aureus), the Gram-negative Escherichia coli (E. coli) and the Gram-negative Pseudomonas aeruginosa (P. aeruginosa). It also promoted wound healing, enhanced angiogenesis and regulated macrophage polarisation in the whole-layer rat diabetic wound model. The multi-functional hydrogel is a dressing with huge potential and prospects in chronic diabetic wound healing.

A small antimicrobial peptide derived from a Burkholderia bacterium exhibits a broad-spectrum and high inhibiting activities against crop diseases

Crop diseases cause significant quality and yield losses to global crop products each year and are heavily controlled by chemicals along with very limited antibiotics composed of small molecules. However, these methods often result in environmental pollution and pest resistance, necessitating the development of new bio-controlling products to mitigate these hazards. To identify effective antimicrobial peptides (AMPs) considered as potential sources of future antibiotics, AMPs were screened from five bacterial strains showing antagonism against a representative phytopathogenic fungus (Rhizoctonia Solani) through the Bacillus subtilis expression system, which has been developed for identifying bacterial AMPs by displaying autolysis morphologies. A total of 5000 colonies were screened, and five displaying autolysis morphologies showed antagonism against R. solani. A novel AMP with the strongest antagonism efficiency was determined and tentatively named HR2-7, which is composed of 24 amino acids with an alpha-helical structure. HR2-7 has strong and broad-spectrum antimicrobial activity, tested against 10 g-positive and -negative bacteria and four phytopathogenic fungi by contact culture in plates with minimal lethal concentrations of 4.0 μM. When applied as purified peptide or in fermented B. subtilis culture solution, HR2-7 showed strong controlling efficiency on plants against diverse fungal and bacterial pathogens. Based on current understanding, HR2-7 is recognized as the first AMP derived from an agricultural antagonistic bacterium. It exhibits wide-ranging and notable antimicrobial efficacy, offering a supplementary approach for managing plant diseases, in addition to conventional chemical pesticides and antibiotics.

Inactivation of antibiotic resistant bacteria by nitrogen-doped carbon quantum dots through spontaneous generation of intracellular and extracellular reactive oxygen species

The widespread antibiotic resistance has called for alternative antimicrobial agents. Carbon nanomaterials, especially carbon quantum dots (CQDs), may be promising alternatives due to their desirable physicochemical properties and potential antimicrobial activity, but their antimicrobial mechanism remains to be investigated. In this study, nitrogen-doped carbon quantum dots (N-CQDs) were synthesized to inactivate antibiotic-resistant bacteria and treat bacterial keratitis. N-CQDs synthesized via a facile hydrothermal approach displayed a uniform particle size of less than 10 nm, featuring a graphitic carbon structure and functional groups including -OH and -NH2. The N-CQDs demonstrated antimicrobial activity against Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus, which was both dose- and time-dependent, reducing the survival rate to below 1 %. The antimicrobial activity was confirmed by live/dead staining. In in vivo studies, the N-CQDs were more efficient in treating drug-resistant bacterial keratitis and reducing corneal damage compared to the common antibiotic levofloxacin. The N-CQDs were shown to generate intracellular and extracellular ROS, which potentially caused oxidative stress, membrane disruption, and cell death. This antimicrobial mechanism was supported by scanning and transmission electron microscopy, significant regulation of genes related to oxidative stress, and increased protein and lactate dehydrogenase leakage. This study has provided insight into the development, application, and mechanism of N-CQDs in antimicrobial applications.

Anti-Methicillin-Resistant Staphylococcus aureus Efficacy of Layer-by-Layer Silver Nanoparticle/Polyacrylic Acid-Coated Titanium Using an In-House Dip Coater

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) is still posing a global challenge in healthcare settings. This bacterial strain is a cause of severe periprosthetic infection, thereby impairing the success of implant insertion. To address this issue, implant surface modification is required. Herein, we developed a novel multilayered silver nanoparticle/polyacrylic acid-coated Ti plate (AgNPs/PAA/Ti) using an in-house dip coater. AgNPs were synthesized and characterized. The dip-coating process was optimized based on the dipping rate, evaporation time, and coating cycle number. Uniform and reproducible coatings were achieved on Ti surfaces, with consistency verified through SEM analysis. The average size of the AgNPs was approximately 36.50 ± 0.80 nm with a PDI of 0.443 ± 0.025, and the zeta potential was measured at around -23.3 ± 2.0 mV. The maximum coating thickness of 83.5 ± 1.3 µm was observed at 15 cycles of dip coating. Moreover, our developed AgNPs/PAA/Ti plate showed both antimicrobial and biofilm-resistant performance, while also exhibiting enhanced biocompatibility with cultured MG63 osteosarcoma cells, maintaining cell viability greater than 70%. We envisage that this material holds significant promise as a candidate for medical implant devices, offering protection against MRSA-associated infection at insertion sites with low vascularity in the future.

Anodized Ti6Al4V-ELI, electroplated with copper is bactericidal against Staphylococcus aureus and enhances macrophage phagocytosis

Implants aim to restore skeletal dysfunction associated with ageing and trauma, yet infection and ineffective immune responses can lead to failure. This project characterized the microbiological and host cell responses to titanium alloy with or without electroplated metallic copper. Bacterial viability counting and scanning electron microscopy quantified and visualized the direct and indirect bactericidal effects of the Cu-electroplated titanium (Cu-Ep-Ti) against two different Staphylococcus aureus strains. Human THP-1 macrophage adhesion and viability was analyzed, along with phagocytosis. Results showed potent antimicrobial activity alongside promising host-immunomodulatory properties. Direct and indirect exposure to Cu-Ep-Ti produced potent bactericidal effects resulting in 94-100% reductions in bacterial viability at 24 h, with complete eradication in some cases. As expected, cytotoxicity was observed in THP-1 macrophages without media exchange, though when media was exchanged at 8, 24 and 48 h cell viability was equivalent to Control-Ti. Interestingly macrophages adhered to the copper material or grown in the presence of copper ions showed 7-fold increase in phagocytosis of S. aureus bioparticles compared to Control-Ti, suggesting a dual bactericidal and host immunomodulatory mechanism. In conclusion, this Cu-electroplated Ti biomaterial can limit bacterial contamination on the implant surface, whilst simultaneously promoting a beneficial antimicrobial immune response.

Stable Antifouling and Antibacterial Coating Based on Assembly of Copper-Phenolic Networks

Biofilm formation on medical devices has become a worldwide issue arising from its resistance to bactericidal agents and presenting challenges to eradicating biofouling adhesion, especially in biological fluids. Metal-phenolic networks have been demonstrated as a versatile and efficient strategy to prevent biofilm formation by endowing medical devices with prolonged antifouling and antibacterial activities in a one-step surface modification. In this study, we report a simple and environmentally friendly method using coordination chemistry between copper ions (Cu2+) and dopamine-containing copolymer to fabricate metal-phenolic network-based coatings. The phenolic groups also imparted the adhesion of glycopolymer-containing dopamine residues to inorganic and organic substrates, resulting in dual antifouling and bactericidal surfaces. 2-gluconamidoethyl methacrylamide monomer (GAEMA) was first copolymerized with dopamine methacrylamide (DMA) using a free-radical polymerization process. The resulting copolymer (GAEMA-DMA), denoted as GADMA, was then mixed with copper ions in a one-step process to form the GADMA-Cu coating. The GADMA-Cu coating was hydrophilic and significantly reduced the water contact angle (WCA) and adsorption of bovine serum albumin protein even after incubation in a bovine serum albumin solution for 30 h. Moreover, the coating exhibited strong antibacterial activity against Escherichia coli and Staphylococcus aureus and was biocompatible with 99% cell viability toward normal human fibroblast (HDFa) cells. Thus, our coating shows great potential for application in medical devices.

Local antimicrobial delivery systems for prophylaxis and treatment of periprosthetic traumatological infections

Infections associated with implants are the most serious complications in joint replacement surgeries and can jeopardize the functionality of orthopedic implants. Local antimicrobial delivery could enable antibiotics to attain concentrations above the minimum inhibitory concentration (MIC) threshold at the joint replacement site while preventing systemic side effects. Therefore, there is a dire need for the development of improved biomaterial-based delivery systems for local antibiotic administration in prosthetic infections. In this context, this review highlights the latest breakthroughs in the design of biomaterial-based formulations intended for the prophylaxis and treatment of prosthetic infections. Delivery systems for distinct forms of administration (i.e., direct intra-articular administration, loading into bone cements, coating of implant surfaces, or loading into hydrogels) are here comprehensively compiled with a focus on the design of microparticles and nanosystems for local antimicrobial administration and their impact on distinct in vitro and in vivo models of implant infections.

Novel Foamed Magnesium Phosphate Antimicrobial Bone Cement for Bone Augmentation

In dental implant surgery, infection is identified as the primary factor contributing to the failure of bone grafts. There is an urgent need to develop bone graft materials possessing antibacterial characteristics to facilitate bone regeneration. Magnesium phosphate bone cement (MPC) is highly desirable for bone regeneration due to its favorable biocompatibility, plasticity, and osteogenic capabilities. However, the limited porosity of conventional MPC hinders the nutrient supply, gas diffusion, and cell infiltration, thereby compromising its osteogenic efficacy. This research focused on the fabrication of a highly porous MPC (CaCO3/CA-MPC) by incorporating citric acid (CA) and calcium carbonate (CaCO3) as foaming agents. The resulting material demonstrated enhanced physicochemical properties, bioactivity, and antimicrobial effects. When compared with conventional MPC, human periodontal ligament stem cells (hPDLSCs) showed improved osteogenic differentiation when cultured with CaCO3/CA-MPC. The inclusion of foaming agents significantly enhanced the antimicrobial efficacy of MPC against both Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli). The results of in vivo anti-infection experiments in rats revealed that 3%CaCO3/CA-MPC displayed superior bactericidal activity compared with Bio-Oss and control groups (p < 0.05), thereby enhancing the anti-infective outcomes post-bone grafting and stimulating osteogenesis in the infected bone defect region. The study demonstrated that MPC containing 3%CaCO3/CA exhibited excellent antimicrobial and osteogenic properties both in vitro and in vivo, suggesting its potential as a promising candidate as bone graft material for dental implant surgeries.

Emerging Resistance Mechanisms in Gram-Positive Bacteria Isolated From Septicemia Cases in ICUs: A Focus on Genotypic Insights

Background Bloodstream infections (BSIs) are associated with high morbidity and mortality, especially in intensive care unit (ICU) settings. The most common Gram-positive pathogens, methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative Staphylococci (CoNS), are likely to cause BSIs. The phenotypic and genotypic characteristics of multidrug-resistant (MDR) Staphylococcal species isolated from patients admitted to the ICU with septicemia were evaluated for better treatment outcomes. Materials and methods A cross-sectional study was conducted at Sree Balaji Medical College and Hospital over two years (July 2022 to June 2024). Blood samples in blood culture bottles received in the laboratory from ICU patients with suspected sepsis were included in this study. The BacT/ALERT® 3D system (bioMérieux, France) was used to assess the bacterial growth. The VITEK® 2 system (bioMérieux, France) and conventional methods were used to identify Gram-positive isolates. Antibiotic susceptibility was determined by the Kirby-Bauer disc diffusion method, and polymerase chain reaction (PCR) was used to detect genes like mecA, icaA, and icaD genes. Results Out of 274 blood samples, eight (2.9%) were contaminants, and 121 (44.2%) were culture-positive as true pathogens. Eighty-seven (71.9%) Gram-positive isolates were identified from the positive blood cultures, of which CoNS was predominant (51, 58.6%), followed by Staphylococcus aureus (25, 28.7%). Methicillin resistance was observed in 10 (13.1%) Staphylococcus aureus and 14 (18.4%) CoNS isolates. PCR detected the mecA gene in 20 (83.3%) methicillin-resistant isolates and biofilm-related genes icaD in 64 (84.2%) and icaA in 58 (76.3%). Vancomycin and teicoplanin showed high effectiveness. Conclusions This study has emphasized the importance of molecular screening for the mecA, icaA, and icaD genes in framing antibiotic regimens. The findings emphasize the efficacy of vancomycin, teicoplanin, and linezolid in combating MDR Staphylococcus infections in ICUs of hospitals and demonstrate the importance of antibiotic stewardship.

Perception of antibiotic use and antibiotic resistance among faculty and staff in a medical school: insights from a mixed mode survey in Bahrain

BACKGROUND

Understanding awareness of antibiotics is crucial in identifying the attitudes of people which could subsequently help shape campaigns and policies addressing this problem. The study aimed to explore awareness of antibiotics use and antibiotic resistance among faculty and staff at the medical institution.

METHODOLOGY

All the study participants (faculty & staff) were asked to complete the survey. The survey consisted of questions ranging from knowledge and use of antibiotics to knowledge about antibiotic resistance. Ninety participants responded for the quantitative survey. After the questionnaire administration, in-depth interviews were conducted with subgroups of faculty, technicians, and administrative staff. The researchers employed a purposive sampling strategy. Around 43 participants volunteered to participate in this interview.

RESULTS

The results showed that 92% of participants reported taking antibiotics, with the majority receiving them from licensed medical providers, while a smaller respondent (12.6%) self-medicated. The concept of "antibiotic resistance" was the most widely recognized, with 47.78% of participants indicating awareness, typically gained from healthcare personnel. The in-depth interviews revealed that the faculty group had the strongest basic knowledge about antibiotics and resistance. When it comes to consequences of ABR, participants mentioned the risk of repeated infection and spread of stronger strains of bacteria that might be difficult to treat soon. The most important suggestion provided by most participants was that the antibiotics should be taken only with a doctor's prescription and consumed for appropriate duration as suggested by the doctor.

CONCLUSIONS

Although the study revealed a strong understanding of antibiotics, awareness regarding antibiotic resistance remained low. The findings emphasize the importance of enhancing communication skills among health professionals and implementing stewardship programs to promote safe antibiotic use and raise awareness about antibiotic resistance.

Research trends and focus of prosthetic joint infections from 2013 to 2023: bibliometric and visualization studies

Background

Postoperative infections in artificial joints provide considerable difficulties in the field of orthopedics, especially after joint replacement procedures. These infections rank among the most severe postoperative consequences, frequently leading to treatment ineffectiveness and reduced quality of life for surgery patients. Consequently, it is crucial to acquire knowledge about worldwide research trends in this area in order to educate clinical practices and improve therapeutic techniques. This work exploits bibliometric analysis to investigate the present state, developing patterns, and main areas of focus in research on artificial joint infection.

Objective

To analyze the research trends, hotspots, and international collaborations on artificial joint infections worldwide from 2013 to 2023.

Methods

Extractions of raw data were made from the WoSCC (Web of Science Core Collection) database. Detailed information collected includes the quantity of publications, authors, citations, publication year, h-index, references, country/region, journal, and keywords. Analysis of the data was conducted using VOSviewer version 1.6.10.0 and CiteSpace version 6.3.R1.

Results

A total of 1,799 articles published between 2013 and 2023 were included in this analysis, showing a steady increase in publication with the United States leading at 553 articles. Infection rates and topics such as biofilm formation and antimicrobial resistance were highly cited, with Mayo Clinic contributing 65 articles as the most prolific institution.

Conclusion

Research on biofilm infections, antibiotic resistance, and new biomarkers is a key focus, particularly on disrupting biofilms and enhancing diagnostics. There's growing attention in biomarkers like α-defensins and exosomal miRNAs for PJI diagnosis, pointing to new clinical uses. Studies on antimicrobial-coated prosthetics and topical agents are also gaining importance in treatment strategies.

Nanostructures in Orthopedics: Advancing Diagnostics, Targeted Therapies, and Tissue Regeneration

Nanotechnology, delving into the realm of nanometric structures, stands as a transformative force in orthopedics, reshaping diagnostics, and numerous regenerative interventions. Commencing with diagnostics, this scientific discipline empowers accurate analyses of various diseases and implant stability, heralding an era of unparalleled precision. Acting as carriers for medications, nanomaterials introduce novel therapeutic possibilities, propelling the field towards more targeted and effective treatments. In arthroplasty, nanostructural modifications to implant surfaces not only enhance mechanical properties but also promote superior osteointegration and durability. Simultaneously, nanotechnology propels tissue regeneration, with nanostructured dressings emerging as pivotal elements in accelerating wound healing. As we navigate the frontiers of nanotechnology, ongoing research illuminates promising avenues for further advancements, assuring a future where orthopedic practices are not only personalized but also highly efficient, promising a captivating journey through groundbreaking innovations and tailored patient care.

Exploring the role of the microbiome of the H. illucens (black soldier fly) for microbial synergy in optimizing black soldier fly rearing and subsequent applications

The symbiotic microbiome in the insect's gut is vital to the host insect's development, improvement of health, resistance to disease, and adaptability to the environment. The black soldier fly (BSF) can convert organic substrates into a protein- and fat-rich biomass that is viable for various applications. With the support of a selective microbiome, BSF can digest and recycle different organic waste, reduce the harmful effects of improper disposal, and transform low-value side streams into valuable resources. Molecular and systems-level investigations on the harbored microbial populations may uncover new biocatalysts for organic waste degradation. This article discusses and summarizes the efforts taken toward characterizing the BSF microbiota and analyzing its substrate-dependent shifts. In addition, the review discusses the dynamic insect-microbe relationship from the functional point of view and focuses on how understanding this symbiosis can lead to alternative applications for BSF. Valorization strategies can include manipulating the microbiota to optimize insect growth and biomass production, as well as exploiting the role of BSF microbiota to discover new bioactive compounds based on BSF immunity. Optimizing the BSF application in industrial setup and exploiting its gut microbiota for innovative biotechnological applications are potential developments that could emerge in the coming decade.

Antimicrobials in Orthopedic Infections: Overview of Clinical Perspective and Microbial Resistance

Orthopedic infections are challenging pathologies that impose a heavy burden on patients and the healthcare system. Antimicrobial therapy is a critical component of the successful management of orthopedic infections, but its effectiveness depends on patient-, surgery-, drug-, and hospital-related factors. The dramatic increase in the emergence of multidrug-resistant microbial strains necessitates new clinical approaches in order to prevent or limit this phenomenon and to ensure a favorable therapeutic outcome. The present paper reviews the currently available antimicrobial strategies in the management of orthopedic infections, highlighting their clinical use related to the occurrence of microbial resistance. Some approaches for reducing antibiotic resistance emergence in orthopedics are also presented. The use of antibiotics tailored to the microorganism's sensitivity profile, patient factors, and pharmacokinetic profile in terms of monotherapy or combinations, the understanding of microbial pathogenicity and resistance patterns, strict control measures in healthcare facilities, the development of new antimicrobial therapies (drugs, devices, technologies), and patient education for improving compliance and tolerance are some of the most important tools for overcoming microbial resistance.

Antifungal activities of Equol against Candida albicans in vitro and in vivo

Candida albicans is an opportunistic fungal pathogen that can cause systemic infections in immunocompromised individuals. Morphological transition and biofilm formation are major virulence factors of C. albicans. Moreover, biofilm enhances resistance to antifungal agents. Therefore, it is urgent to identify new and effective compounds to target the biofilm of C. albicans. In the present study, the antifungal activities of equol against C. albicans were investigated. In vitro, the microdilution analysis and spot assay result showed that equol exhibited potent inhibitory activities against C. albicans. Further investigations confirmed that the antifungal effects of equol involved interference with the transition from yeast to hypha and biofilm formation of C. albicans. In addition, transcriptome sequencing and reverse transcription-quantitative PCR (qRT-PCR) analysis showed that equol significantly downregulated the expression of several genes in the Ras1-cAMP-PKA pathway related to hyphae and biofilm formation and significantly upregulated the expression of the negative transcriptional repressors RFG1 and TUP1. Moreover, equol effectively reduced the production of cAMP, a key messenger in the Ras1-cAMP-PKA pathway, while supplementation with cAMP partly rescued the equol-induced defects in hyphal development. Furthermore, in a mouse model of systemic candidiasis (SC), equol treatment significantly decreased the fungal burden (liver, kidneys, and lung) in mice and local tissue damage, while enhancing the production of interleukin-10 (IL-10). Together, these findings confirm that equol is a potentially effective agent for treatment of SC.

An in silico approach for identification of lead compound as FtsZ inhibitor

The remarkable conservation of the FtsZ among Gram-positive and Gram-negative bacteria, a crucial GTPase in bacterial cell division, has emerged as a promising antibacterial drug target to combat antibacterial resistance. There have been several coordinated efforts to develop inhibitors against FtsZ which can also serve as potential candidates for future antibiotics. In the present study, a natural product-like library (≈50,000 compounds) was employed to conduct HTVS against Staphylococcus aureus FtsZ protein (PDB Id: 6KVP). Additionally, molecular docking was carried out in two modes, SP and XP docking, using the Schrödinger suite. The glide scores of ligands obtained by XP docking were further summarized and compared with the control ligands (ZI1- co-crystal and PC190723-a compound undergoing clinical trial). Using the Prime-MM-GBSA approach, BFE calculations were performed on the top XP-scored ligands (≈598 compounds). These hits were also evaluated for ADMET parameters using the Qikprop algorithm, SwissADME, and in silico carcinogenicity testing using Carcinopred-El. Based on the results, ligand 4-FtsZ complex was considered for the 300 ns MDS analysis to get insights into its binding modes within the catalytic pocket of FtsZ protein. The analysis revealed that the amide linkage sandwiched between the triazole and 1-oxa-8-azaspirodecan-8-ium moiety (Val203) as well as the aminoethyl group present at 1st position on the triazole moiety (Leu209, Leu200, Asp210, and Ala202) were responsible for the FtsZ inhibitory activity, owing to their crucial interactions with key amino acid residues. Further, the complex also displayed good protein-ligand stability, ultimately predicting ligand 4 as a potent lead compound for the inhibition of FtsZ. Thus, our in silico findings will serve as a framework for in-depth in-vitro and in-vivo investigations encouraging the development of FtsZ inhibitors as a new generation of antibacterial agents.

In Situ Rapid Preparation of the Cu-MOF Film on Titanium Alloys at Low Temperature

Titanium alloys are widely used in marine environments and medical fields due to their excellent corrosion resistance and high specific strength. However, their good biocompatibility can lead to severe biofouling, thereby limiting their effectiveness. To inhibit biofouling on the surface of titanium alloys, this study proposes an antifouling solution, which involves the in situ preparation of Cu-MOF film on titanium alloys by leveraging the antibacterial properties of Cu ions. Here, the dense and stable TiO2 film on the surface of Ti-6Al-4V titanium alloy was removed by alkali-heat treatment; meanwhile, a porous surface structure was simultaneously obtained where OH- ions were retained. In the subsequent step, the retained OH- ions in the pores attracted Cu2+ ions in solution to form Cu(OH)2 in the pores, providing active sites for the formation of Cu-MOFs. Subsequently, Cu(OH)2 reacted with organic ligand (1,3,5-benzenetricarboxylic acid, BTC) at room temperature to form Cu-MOFs in the pores, which then grew quickly to cover the alkali-heat-treated surface within 1 h. The formation mechanism of Cu-MOF film on Ti-6Al-4V was elucidated, which provides a reference for designing and preparing multifunctional MOF film in situ on titanium alloys. The stability of in situ-grown Cu-MOF samples and their inhibitory effects on bacteria and microalgae have also been verified. The results indicate that although the stability of Cu-MOFs is relatively poor, their bactericidal and algicidal effects are extremely significant, suggesting that this material has significant potential for short-term applications that require high antibacterial performance.

Development of a dextrin-vitamin D3 micelle nanocarrier for the antimicrobial peptide LLKKK18 as a potential therapeutic agent for bone infections

In this work, an expedite synthesis was developed for a self-assembled micelle carrier for the antimicrobial peptide LL18. Covalent one-pot functionalization of dextrin with succinylated vitamin D3 and succinic anhydride produced an amphiphilic material that undergoes self-assembly into micelles in aqueous medium. Succinylated dextrin-vitamin D3 micelles were efficiently loaded with LL18 by electrostatic and hydrophobic interactions. Remarkably, the LL18-loaded micelle formulation dramatically improves the antibacterial activity of free LL18 against S. aureus, completely abrogates its severe hemolytic activity, redirects the internalization of LL18 from the perinuclear region of osteoblasts to the lysosomes and reduces cellular toxicity towards osteoblasts and macrophages. Overall, this work demonstrates that self-assembled micelle formulations based on dextrin, vitamin D3 and antimicrobial peptides, are promising platforms to develop multifunctional antibiotic-independent antimicrobial agents, not prone to the development of bacterial resistance, to treat bone infections.

Therapeutic Phage Candidates for Targeting Prevalent Sequence Types of Carbapenem-Resistant Escherichia coli

Carbapenem-resistant Escherichia coli (CREC) is a global threat to public health; therefore, alternative treatment options are urgently needed. Bacteriophages have emerged as promising candidates for combating CREC infections. This study aimed to investigate the genetic basis of phage sensitivity in CREC by evaluating carbapenem resistance among multidrug-resistant (MDR) E. coli isolated in Daegu, South Korea and analyzing their sequence types (STs) with phage susceptibility spectra. Among the 60 MDR E. coli isolates, 80.4% were identified as CREC, with 77.0% demonstrating resistance to imipenem and 66.6% to meropenem. Moreover, 70 lytic E. coli bacteriophages were isolated from hospital sewage water and evaluated against those 60 E. coli isolates. The phages exhibited lytic activity of 33%-60%, with average titers ranging from 5.6 × 1012 to 2.4 × 1013 PFU/mL (Plaque-Forming Unit). Furthermore, multilocus sequence typing (MLST) analysis of the bacterial isolates revealed 14 distinct STs, mostly belonging to ST131, ST410, and ST648. Notably, the phage susceptibility spectra of ST73, ST13003, ST648, ST2311, ST167, ST405, ST607, ST7962, and ST131 were significantly different. Thus, the isolated phages can effectively lyse CREC isolates, particularly those with clinically dominant STs. Conversely, ST410 exhibited a 14.2%-87.14% susceptibility spectrum, whereas ST1139, ST1487, ST10, and ST206 did not lyse, suggesting the presence of more resistant STs. Future studies are warranted to identify the reasons behind this resistance and address it. Ultimately, this study will aid in developing focused treatments to address these pressing global health issues.

Emerging Strategies to Prevent Bacterial Infections on Titanium-Based Implants

Titanium and titanium alloys remain the gold standard for dental and orthopedic implants. These materials are heavily used because of their bioinert nature, robust mechanical properties, and seamless integration with bone. However, implant-associated infections (IAIs) remain one of the leading causes of implant failure. Eradicating an IAI can be difficult since bacteria can form biofilms on the medical implant, protecting the bacterial cells against systemic antibiotics and the host's immune system. If the infection is not treated promptly and aggressively, device failure is inevitable, leading to costly multi-step revision surgeries. To circumvent this dire situation, scientists and engineers continue to develop novel strategies to protect the surface of medical implants from bacteria. In this review, details on emerging strategies to prevent infection in titanium implants are reported. These strategies include anti-adhesion properties provided by polymers, superhydrophobic, superhydrophilic, and liquid-infused surface coatings, as well as strategies and coatings employed to lyse the bacteria. Additionally, commercially available technologies and those under preclinical trials are examined while discussing current and future trends.

Assessment of the antimicrobial and antibiofilm activity of the combination of N-acetyl cysteine and carvacrol against Staphylococcus aureus, the most common orthopedic infectious agent

BACKGROUND

The increasing prevalence of antibiotic-resistant bacterial infections has led to the search for new approaches.

OBJECTIVE

This study aimed to evaluate the effects of carvacrol and N-acetyl cysteine, both individually and in combination, on the planktonic cells and biofilm formations of Staphylococcus aureus, including methicillin-resistant and methicillin-sensitive strains. Additionally, the study sought to perform cytotoxicity tests and chemical characterization to further understand the properties and potential applications of these substances.

METHODS

A total of 19 S. aureus strains were included in the study. Minimum inhibitory concentration and minimum bactericidal concentration were determined by assays. Synergy analysis tests were carried out. Cytotoxicity tests were conducted on the fibroblast cell line. Characterization test was performed.

RESULTS

While Minimum inhibitory concentration and minimum bactericidal concentration values for carvacrol varied between 250 and 500 μg/ml, these values were in the range of 32-64 mg/ml for N-acetyl cysteine. Biofilm formation activities were identified. A total of eight strains, including six clinical and two standard strains with the highest biofilm-forming ability, were selected for combination studies. The combination of Carvacrol and N-acetyl cysteine exhibited synergistic and partially synergistic effects on the tested planktonic and biofilm strains, and these effects were dose-dependent. Carvacrol was found to be the most active drug at the end of 24, 48, and 72 h. Regarding the synergistic effect of N-acetyl cysteine + carvacrol, it was revealed to exhibit higher activity than N-acetyl cysteine and lower activity than carvacrol.

CONCLUSION

The combination of carvacrol and N-acetyl cysteine demonstrated synergistic and partially synergistic effects against both planktonic and biofilm forms of Staphylococcus aureus. These results suggest potential for novel approaches in managing orthopedic infections, warranting further research to explore their therapeutic applications.

Hybrid zinc oxide nanocoating on titanium implants: Controlled drug release for enhanced antibacterial and osteogenic performance in infectious conditions

Implant-associated bacterial infections are a primary cause of complications in orthopedic implants, and localized drug delivery represents an effective mitigation strategy. Drawing inspiration from the morphology of desiccated soil, our group has developed an advanced drug-delivery system augmented onto titanium (Ti) plates. This system integrates zinc oxide (ZnO) nanorod arrays with a vancomycin drug layer along with a protective Poly(lactic-co-glycolic acid) (PLGA) coating. The binding between the ZnO nanorods and the drug results in attached drug blocks, isolated by desiccation-like cracks, which are then encapsulated by PLGA to enable sustained drug release. Additionally, the release of zinc ions and the generation of reactive oxygen species (ROS) from the ZnO nanorods enhance the antibacterial efficacy. The antibacterial properties of ZnO nanorod-drug-PLGA system have been validated through both in vitro and in vivo studies. Comprehensive investigations were conducted on the impact of bacterial infections on bone defect regeneration and the role of this drug-delivery system in the healing process. Furthermore, the local immune response was analyzed and the immunomodulatory function of the system was demonstrated. Overall, the findings underscore the superior performance of the ZnO nanorod-drug-PLGA system as an efficient and safe approach to combat implant-associated bacterial infections. STATEMENT OF SIGNIFICANCE: Implant-associated bacterial infections pose a significant clinical challenge, particularly in orthopedic procedures. To address this, we developed an innovative ZnO nanorod-drug-PLGA system for local antibiotic delivery on conventional titanium implants. This system is biodegradable and features a unique desiccation-like structure that enables sustained drug release, along with the active substances released from the ZnO nanorods. In a rat calvarial defect model challenged with S. aureus, our system demonstrated remarkable antibacterial efficacy, significantly enhanced bone defect regeneration, and exhibited local immunomodulatory effects that support both infection control and osteogenesis. These breakthrough findings highlight the substantial clinical potential of this novel drug delivery system and introduce a transformative coating strategy to enhance the functionality of traditional metallic biomaterials.

A review on the promising antibacterial agents in bone cement-From past to current insights

Antibacterial bone cements (ABCs), such as antibiotic-loaded bone cements (ALBCs), have been widely utilized in clinical treatments. Currently, bone cements loaded with vancomycin, gentamicin, tobramycin, or clindamycin are approved by the US Food and Drug Administration. However, traditional ALBCs exhibit drawbacks like burst release and bacterial resistance. Therefore, there is a demand for the development of antibacterial bone cements containing novel agents to address these defects. In this review, we provide an overview and prospect of the new antibacterial agents that can be used or have the potential to be applied in bone cement, including metallic antibacterial agents, pH-switchable antibacterial agents, cationic polymers, N-halamines, non-leaching acrylic monomers, antimicrobial peptides and enzymes. Additionally, we have conducted a preliminary assessment of the feasibility of bone cement containing N-halamine, which has demonstrated good antibacterial activities. The conclusion of this review is that the research and utilization of bone cement containing novel antibacterial agents contribute to addressing the limitations of ALBCs. Therefore, it is necessary to continue expanding the research and use of bone cement incorporating novel antibacterial agents. This review offers a novel perspectives for designing ABCs and treating bone infections.

Alginate/hyaluronic acid/gelatin ternary blended films as pH-sensitive drug carriers: In vitro ampicillin release and kinetic studies

Researchers continuously focused on the fabrication of innovative drug delivery systems to prevent microbial infections while minimizing systemic side effects. Among these, pH-sensitive antibiotic release systems based on bio-based materials have gained great attention due to their ability to precisely modulate drug kinetics and enhance therapeutic efficacy. Herein, pH-sensitive alginate/hyaluronic acid/gelatin ternary blended films were fabricated for the controlled release of ampicillin. Swelling capacity, hydrolytic degradation profile, pH reversibility and in vitro ampicillin release behavior of produced films were investigated in both simulated gastric (pH 1.2) and intestinal (pH 7.4) environments. The cumulative release amount of ampicillin at pH 1.2 (61.0 ± 1.07 mg drug/g polymer) was greater than that of at pH 7.4 (43.0 ± 1.05 mg drug/g polymer) proved that release behavior of ampicillin for produced films is pH-dependent. Based on the fitted release data, best fit was found as the first-order kinetic model with the highest R2 values of 0.966 and 0.962 for both pH conditions. According to Korsmeyer-Peppas model, drug release mechanism is also controlled by case II-transport. Furthermore, produced films demonstrated excellent cytocompatibility. All results revealed that obtained films could be a promising drug carrier to traditional targeting systems for site-specific, pH-sensitive ampicillin delivery in both gastric and intestine.

Bactericidal activity of esculetin is associated with impaired cell wall synthesis by targeting glutamate racemase of Neisseria gonorrhoeae

Neisseria gonorrhoeae (NG), the causative organism of gonorrhea, has been classified by the World Health Organization as 'Priority' two organism owing to its increased resistance to antibiotics and even failure of recommended dual therapy with ceftriaxone and azithromycin. As a result, the general and reproductive health of infected individuals is severely compromised. The imminent public health catastrophe of antimicrobial-resistant gonococci cannot be understated, as t he of severe complications and sequelae of infection are not only increasing but their treatment has also become more expensive. Tenacious attempts are underway to discover novel drug targets as well as new drugs to fight against NG. Therefore, a considerable number of phytochemicals have been tested for their remedial intercession via targeting bacterial proteins. The MurI gene encodes for an enzyme called glutamate racemase (MurI) that is primarily involved in peptidoglycan (PG) biosynthesis and is specific to the bacterial kingdom and hence can be exploited as a potential drug target for the treatment of bacterial diseases. Accordingly, diverse families of phytochemicals were screened in silico for their binding affinity with N. Gonorrhoeae MurI (NG-MurI) protein. Esculetin, one of the shortlisted compounds, was evaluated for its functional, structural, and anti-bacterial activity. Treatment with esculetin resulted in growth inhibition, cell wall damage, and altered permeability as revealed by fluorescence and electron microscopy. Furthermore, esculetin inhibited the racemization activity of recombinant, purified NG-MurI protein, one of the enzymes required for peptidoglycan biosynthesis. Our results suggest that esculetin could be further explored as a lead compound for developing new drug molecules against multidrug-resistant strains.

Effectiveness of selective antibiotics use in ESBL-related UTIs

BACKGROUND

Urinary tract infections (UTIs) are the second most common infection, affecting 150 million people each year worldwide. Enterobacteriaceae species expressing extended-spectrum β-lactamases (ESBLs) are on the rise across the globe and are becoming a severe problem in the therapeutic management of clinical cases of urinary tract infection. Knowledge of the prevalence and antibiogram profile of such isolates is essential to develop an appropriate treatment methodology. This study aimed to investigate the prevalence of Enterobacteriaceae isolates exhibiting ESBL and their selective oral antibiogram profile at the district general hospital, Polonnaruwa.

RESULTS

A total of 4386 urine specimens received to the Microbiology Laboratory during the study period. Among them, 1081 (24.6%) showed positive results for urine culture while 200/1081 specimens showed ESBL isolates. Out of the selected 200 specimen's majority (67.5%) of samples received from the In-Patient Department. There were 200 patients and reported that 115 (57.5%) were females and 85 (42.5%) were males. The majority (51%) of the patients belong to the age group of 55-74 years. Among the ESBLs positive specimens, the majority 74.5% (n = 149) identified organisms were E. coli followed by Klebsiella spp.17.5% (n = 35), Enterobacteriaceae 7% (n = 14) and only1% (n = 2) isolate of Proteus spp. Mecillinam (87.92%) and Nitrofurantoin (83.2%) showed higher effectiveness against E. coli. Nitrofurantoin showed the highest effectiveness against Klebsiella spp. (40%), other Enterobacteriaceae spp. (100%). Proteus spp. showed 100% effectiveness and resistance respectively against Ciprofloxacin, Cotrimoxazole and Nitrofurantoin.

CONCLUSION

The most predominant ESBLs producing uro-pathogen was the E. coli in the study setting and E. coli had higher sensitivity rate against Mecillinam. Among currently used oral antibiotics Nitrofurantoin was the best choice for UTIs caused by ESBL producers.

Improving Biological Performance of 3D-Printed Scaffolds with Garlic-Extract Nanoemulsions

Complex bone diseases such as osteomyelitis, osteosarcoma, and osteoporosis often cause critical-size bone defects that the body cannot self-repair and require an advanced bone graft material to repair. We have fabricated 3D-printed tricalcium phosphate bone scaffolds functionalized with garlic extract (GE). GE was encapsulated in a nanoemulsion (GE-NE) to enhance bioavailability and stability. GE-NE showed ∼73% drug encapsulation efficiency, with an average particle size of 158 nm and a zeta potential of -14.2 mV. Release of GE-NEs from the scaffold displayed a controlled and biphasic release profile at both acidic and physiological mediums. Results from the osteosarcoma study show that GE-NE demonstrated ∼88% reduction in cancer cell growth while exhibiting no cytotoxicity toward bone-forming cells. Interaction for the functionalized scaffold with Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa showed a substantial reduction in bacteria growth by more than 90% compared to the unfunctionalized scaffold. These findings demonstrate the potential of GE-NEs-treated porous scaffolds to treat bone-related diseases, particularly for non-load bearing applications.

Comparison of Mutant Prevention Concentrations of Fluoroquinolones Against ESBL-Positive and ESBL-Negative Klebsiella pneumoniae Isolates from Orthopedic Patients

The majority of Klebsiella pneumonia isolates possess the extended-spectrum beta-lactamase (ESBL) enzymes. Therefore, K. pneumoniae can easily develop drug resistance. How to effectively overcome the problem of drug resistance in K. pneumoniae is still a research hotspot. This study aimed to compare the mutant prevention concentration (MPC) of ESBL-positive and ESBL-negative K. pneumoniae isolated from orthopedic patients, which may provide a basis for the effective use of drugs to control the enrichment of resistance mutants of K. pneumoniae. The MPC90 values of 55 isolates of ESBL-positive K. pneumoniae against 4 fluoroquinolones were 32 µg/mL for levofloxacin and gatifloxacin, 16 µg/mL for ciprofloxacin, and 4 µg/mL for gemifloxacin. The selection index value was 8 for levofloxacin and ciprofloxacin and 2 for gemifloxacin and gatifloxacin, respectively. For ESBL-negative K. pneumoniae isolates, the MPC90 values were 16 µg/mL for levofloxacin and ciprofloxacin, 4 µg/mL for gemifloxacin, and 32 µg/mL for gatifloxacin. The selection index value was 8 for levofloxacin and ciprofloxacin, 2 for gemifloxacin, and 4 for gatifloxacin. For the ESBL-positive K. pneumoniae, the %T>MIC90 order was gemifloxacin > levofloxacin > ciprofloxacin > gatifloxacin. For the ESBL-negative K. pneumoniae, the %T>MIC90 order was levofloxacin > gemifloxacin > ciprofloxacin > gatifloxacin. The mutant-preventing ability of gatifloxacin and gemifloxacin was the strongest among the 4 fluoroquinolones. So gemifloxacin may be the first choice of drug to treat K. pneumoniae infection.

Characteristics of Metallic Nanoparticles (Especially Silver Nanoparticles) as Anti-Biofilm Agents

Biofilm-associated infections account for a large proportion of chronic diseases and pose a major health challenge. Metal nanoparticles offer a new way to address this problem, by impairing microbial growth and biofilm formation and by causing degradation of existing biofilms. This review of metal nanoparticles with antimicrobial actions included an analysis of 20 years of journal papers and patent applications, highlighting the progress over that time. A network analysis of relevant publications showed a major focus on the eradication of single-species biofilms formed under laboratory conditions, while a bibliometric analysis showed growing interest in combining different types of metal nanoparticles with one another or with antibiotics. The analysis of patent applications showed considerable growth over time, but with relatively few patents progressing to be granted. Overall, this profile shows that intense interest in metal nanoparticles as anti-biofilm agents is progressing beyond the confines of simple laboratory biofilm models and coming closer to clinical application. Looking to the future, metal nanoparticles may provide a sustainable approach to combatting biofilms of drug-resistant bacteria.

Novel Antimicrobial Agents Based on Zinc-Doped Hydroxyapatite Loaded with Tetracycline

In this paper, we present for the first time the development of zinc-doped hydroxyapatite enriched with tetracycline (ZnHApTe) powders and provide a comprehensive evaluation of their physico-chemical and biological properties. Various techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) were used for the sample's complex evaluation. Moreover, the biocompatibility of zinc-doped hydroxyapatite (ZnHAp) and ZnHApTe nanoparticles was evaluated with the aid of human fetal osteoblastic cells (hFOB 1.19 cell line). The results of the biological assays suggested that these nanoparticles hold great promise as potential candidates for the future development of novel biocompatible and antimicrobial agents for biomedical applications. The antimicrobial properties of the ZnHAp and ZnHApTe nanoparticles were assessed using the standard reference microbial strains Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Candida albicans ATCC 10231. The results of the in vitro antimicrobial assay demonstrated that both tested materials exhibited good antimicrobial activity. Additionally, these data also indicated that the antimicrobial effects of the ZnHAp nanoparticles were intensified by the presence of tetracycline (Te). Furthermore, the results also suggested that the antimicrobial activity of the samples increased with the incubation time.

Antibiotic utilization at an orthopedic inpatient department in a large governmental hospital in the north of the West Bank, Palestine; a retrospective observational study

BACKGROUND

Studies evaluating the patterns of antibiotic consumption are becoming increasingly necessary as a result of the increased use of antibiotics and development of antibiotic resistance globally. This study aimed to evaluate the use of antibiotics in in terms of both quantity and quality at the largest surgical hospital in the north of the West Bank, Palestine.

METHODS

An observational retrospective study with a total population sampling method was conducted to collect data from the inpatients of the orthopedic departments of a large governmental hospital in the northern West Bank, Palestine. The data were collected from patients' files and evaluated using the anatomical therapeutic chemical and defined daily dose (ATC/DDD) methodology, and the drug utilization 90% (DU90%) index. The ATC/DDD methodology, designed by the World Health Organization (WHO), as a well-trusted and standardized tool that allows measuring and comparing antibiotic utilization across different contexts. Antibiotic prescriptions were classified using the World Health Organization Access, Watch and Reserve classification (WHO AWaRe).

RESULTS

Of the 896 patients who were admitted to the hospital in the year 2020 and included in the study, 61.9% were males, and 38.1% were females. The percentage of patients who received antibiotics was 97.0%, and the overall antibiotic usage was 107.91 DDD/100 bed days. The most commonly prescribed antibiotic was cefazolin (50.30 DDD/100 bed days), followed by gentamicin (24.15 DDD/100 bed days) and ceftriaxone (17.35 DDD/100 bed days). The DU90% segment comprised four different agents. Classification of antibiotics according to the WHO AWaRe policy revealed that 75.9% of antibiotics were prescribed from the access list.

CONCLUSION

This study comes as part of the efforts exerted to combat the growing problem of antibiotic resistance in Palestine. Our results showed that the consumption of antibacterial agents in the orthopedic unit at a large governmental hospital in Palestine was relatively high. The results of this study provide valuable insights for the decision-makers to create policies aimed at regulating antibiotic prescriptions. This study also aims to provide a look into the antibiotic prescription patterns, offering a clearer understanding of the current situation of antibiotic consumption in Palestine. It also emphasizes the need for antibiotic stewardship and surveillance programs.

Antimicrobial Peptide Identified via Machine Learning Presents Both Potent Antibacterial Properties and Low Toxicity toward Human Cells

Preventing infection is a critical clinical challenge; however, the extensive use of antibiotics has resulted in remarkably increased antibiotic resistance. A variety of antibiotic alternatives including antimicrobial peptides (AMPs) have been studied. Unfortunately, like most conventional antibiotics, most current AMPs have shown significantly high toxicity toward the host, and therefore induce compromised host responses that may lead to negative clinical outcomes such as delayed wound healing. In this study, one of the AMPs with a short length of nine amino acids was first identified via machine learning to present potentially low cytotoxicity, and then synthesized and validated in vitro against both bacteria and mammalian cells. It was found that this short AMP presented strong and fast-acting antimicrobial properties against bacteria like Staphylococcus aureus, one of the most common bacteria clinically, and it targeted and depolarized bacterial membranes. This AMP also demonstrated significantly lower (e.g., 30%) toxicity toward mammalian cells like osteoblasts, which are important cells for new bone formation, compared to conventional antibiotics like gentamicin, vancomycin, rifampin, cefazolin, and fusidic acid at short treatment times (e.g., 2 h). In addition, this short AMP demonstrated relatively low toxicity, similar to osteoblasts, toward an epithelial cell line like BEAS-2B cells.

Antibiotic Resistance Profiles of Escherichia coli and Salmonella spp. Isolated From Dairy Farms and Surroundings in a Rural Area of Western Anatolia, Turkey

Background Antibiotic resistance is a significant public health issue worldwide. Antibiotic-resistant zoonotic bacteria such as Escherichia coli (E. coli), Campylobacter, Salmonella, Listeria, Coxiella, and Mycobacterium can be particularly isolated from biofertilizers. Epidemiological studies have shown that cases of foodborne infections and intoxications are significantly related to animal-derived foods. The presence of these species in aquatic environments indicates areas or organisms contaminated with animal or human feces. Especially, the presence of E. coli in aquatic environments has become a serious problem worldwide. Pathogenic strains of E. coli cause waterborne and foodborne diseases. Materials and methods This study included a total of 290 samples collected from five different dairy farms between April and September 2023 which comprised 20 samples of cow manure, 20 samples of milk, three samples of dairy workers' hand washing water, five samples of soil, five samples of water, and five samples of vegetables. The samples taken from the farms were homogenized with 0.1% peptone water at a ratio of 1/10. They were then cultured on xylose lysine deoxycholate (XLD), eosin methylene blue agar (EMB), and blood agar media, and gram-negative colonies were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and the VITEK2 automated system (BioMerieux Inc., Durham, NC). Amplification of the isolated DNA extracts was performed with A.B.T.™ 2X HS-PCR MasterMix (A.B.T Laboratory Industry, Arnavutköy, Turkey) in the SimpliAmp™ thermal cycler (Thermo Fischer Scientific Inc., Waltham, MA) and visualized by agarose gel electrophoresis. Results Among the 52 E. coli strains isolated in our study, the highest antibiotic sensitivity rate was observed in meropenem, while the lowest sensitivity rates were determined in cefazolin and cefuroxime. While two of the Salmonella spp. (n = 2) isolates were found to be resistant to tetracycline, and one was found to be resistant to penicillin and ampicillin. No resistance to trimethoprim/sulfamethoxazole was detected in either isolate. Extended-spectrum beta-lactamases (ESBLs) were detected in only four (7.7%) E. coli strains. While tetA, tetB, and TEM genes were seen in almost all E. coli strains, they were not found in Salmonella spp. Conclusion In conclusion, our study revealed the presence of antimicrobial resistance genes in E. coli and Salmonella spp. isolates collected from various farms and environmental samples, which render the antimicrobials used for disease treatment ineffective. Consequently, research should be undertaken to prevent the development of new resistance genes in our country, as creating new medications and treatment strategies for these diseases is costly and time-intensive.

Unearthing the therapeutic benefits of culinary-medicinal mushrooms for humans: Emerging sustainable bioresources of 21st century

Global interest in mushroom farming techniques has grown in the last few years. Despite not making up a large amount of the human diet at the moment, the nutritional worth of mushrooms has prompted their usage. The three main segments of the global mushroom industry are wild, culinary (edible), and medicinal mushrooms. The quality food that mushrooms provide can be utilized to build agricultural ecosystems that are more sustainable for increasing productivity and enhancing the effectiveness of resource usage. This is mostly because mushrooms can be utilized for the recycling of biomass and remains from crop production. Culinary-medicinal mushrooms are becoming more and more important because of their nutrient density, dietary value, and health advantages. Given its many bioactive components, which include polysaccharides, proteins, vitamins, minerals, dietary fiber, and secondary metabolites, mushrooms have been utilized extensively as health foods. These mushrooms exhibit pharmacological activities and possess prebiotic and antibacterial capabilities. This review provides information on the latest advancements in the sustainable cultivation of mushrooms, particularly with nontraditional substrates, and their potential therapeutic uses. Furthermore, some of the newest developments and difficulties in the production of mushrooms are explored.

Trends in Extended Oral Antibiotic Prophylaxis Utilization Following Primary and Revision Total Hip Arthroplasty From 2010 to 2022

BACKGROUND

In patients considered high-risk for infection, extended oral antibiotic (EOA) prophylaxis has been demonstrated to reduce rates of prosthetic joint infection following total hip arthroplasty (THA). Although national guidelines regarding their use have not yet been created, the increase in literature surrounding EOA prophylaxis suggests a potential change in practice patterns. The purpose of this study was to investigate the trends in utilization of EOA prophylaxis following THA from 2010 to 2022 and identify prescription patterns.

METHODS

A total of 646,059 primary THA and 51,879 aseptic revision THA patients were included in this study. Patients who underwent primary or aseptic revision THA between 2010 and 2022 were identified in a national administrative claims database. Rates and duration of EOA prescriptions were calculated. A secondary analysis examined rates of utilization across demographics, including patients considered high risk for infection.

RESULTS

From 2010 to 2022, utilization of EOA increased by 366% and 298% following primary and revision THA, respectively. Of patients prescribed postoperative antibiotics, 30% and 59% were prescribed antibiotics for more than 7 days following primary and revision THA, respectively. Rates of utilization were similar between high-risk individuals and the general population.

CONCLUSIONS

Rates of utilization of EOA prophylaxis after THA have increased significantly since 2010. As current trends demonstrate a wide variation in prescription patterns, including in length of antibiotic duration and in patient population prescribed, guidelines surrounding the use of EOA prophylaxis after THA are necessary to promote antibiotic stewardship while preventing rates of periprosthetic joint infection.

Characteristics and Outcomes of Occult Infections in Presumed Aseptic Nonunions: A Retrospective Cohort Study

OBJECTIVES

To determine (1) the rate of positive cultures in presumed aseptic nonunions, (2) the rate and microbial spectrum of positive cultures that represented occult infection, and (3) rates of nonunion healing.

METHODS

DESIGN

Retrospective cohort study.

SETTING

Tertiary referral center.

PATIENTS SELECTION CRITERIA

Adult patients with a presumed aseptic nonunion treated with single-stage revision between 2002 and 2022.

OUTCOME MEASURES AND COMPARISONS

The rate of positive cultures compared for 2 protocols: old: 1-2 samples cultured 7 days versus new: 5 samples cultured 14 days. The rate of positive cultures meeting occult infection criteria with the new protocol (≥2 samples with phenotypically indistinguishable microorganisms, or ≥1 sample with a high virulent microorganism). Nonunion healing rates between protocols and between groups based on culture results with the new protocol.

RESULTS

One hundred seventy-nine patients were included. The rate of positive cultures was 14% (n = 15/105) with the old protocol and 51% (n = 38/74) with the new protocol (P < 0.001). With the new protocol, the rate of positive cultures meeting occult infection criteria was 19% (n = 14/74), and coagulase-negative staphylococci (48%) and Cutibacterium acnes (38%) were the most common microorganisms. Nonunion healing rates after the primary revision did not differ between protocols (old: 82% vs. new: 86%, P = 0.41) and groups based on culture result (sterile: 86% vs. occultly infected: 93%, P = 0.66). The final overall nonunion healing rate was 97%.

CONCLUSIONS

Occult infections were identified in 1 in 5 presumed aseptic nonunions using a standardized protocol with 5 intraoperative samples cultured 14 days and were predominantly caused by slow growing, gram-positive microorganisms. The local spectrum and antimicrobial sensitivity of occult infections should be considered when developing empiric antimicrobial protocols. Patients with presumed aseptic nonunions can expect high healing rates, regardless of the culture result.

LEVEL OF EVIDENCE

Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.