Selective Delivery of Clindamycin Using a Combination of Bacterially Sensitive Microparticle and Separable Effervescent Microarray Patch on Bacteria Causing Diabetic Foot Infection.

INTRODUCTION: Diabetic foot infection (DFI) is one of the complications of diabetes mellitus. Clindamycin (CLY) is one of the antibiotics recommended to treat DFI, but CLY given orally and intravenously still causes many side effects. METHODS: In this study, we encapsulated CLY in a bacteria sensitive microparticle system (MP-CLY) using polycaprolactone (PCL) polymer. MP-CLY was then delivered in a separable effervescent microarray patch (MP-CLY-SEMAP), which has the ability to separate between the needle layer and separable layer due to the formation of air bubbles when interacting with interstitial fluid in the skin. RESULT: The characterization results of MP-CLY proved that CLY was encapsulated in large amounts as the amount of PCL polymer used increased, and there was no change in the chemical structure of CLY. In vitro release test results showed increased CLY release in media cultured with Staphylococcus aureus bacteria and showed controlled release. The characterization results of MPCLY-SEMAP showed that the developed formula has optimal mechanical and penetration capabilities and can separate in 56 ± 5.099 s. An ex vivo dermatokinetic test on a bacterially infected skin model showed an improvement of CLY dermatokinetic profile from MP-CLY SEMAP and a decrease in bacterial viability by 99.99%. CONCLUSION: This research offers proof of concept demonstrating the improved dermatokinetic profile of CLY encapsulated in a bacteria sensitive MP form and delivered via MP-CLY-SEMAP. The results of this research can be developed for future research by testing MP-CLY-SEMAP in vivo in appropriate animal models.

The effect of different antibiotic combinations in calcium sulfate cement on the growth of Cutibacterium acnes and Staphylococcus periprosthetic shoulder infection isolates.

BACKGROUND: Periprosthetic joint infections (PJI) of the shoulder are a devastating complication of shoulder arthroplasty and are commonly caused by Staphylococcus and Cutibacterium acnes. Absorbable calcium sulfate (CS) beads are sometimes used for delivering antibiotics in PJI. This study evaluates the in vitro effect of different combinations of gentamicin, vancomycin, and ertapenem in beads made from CS cement on the growth of C acnes and coagulase-negative Staphylococcus (CNS) strains. METHODS: Three strains of C acnes and 5 strains of CNS from clinically proven shoulder PJI were cultured and plated with CS beads containing combinations of vancomycin, gentamicin, and ertapenem. Plates with C acnes were incubated anaerobically while plates with Staphylococcus were incubated aerobically at 37 °C. Zones of inhibition were measured at intervals of 3 and 7 days using a modified Kirby Bauer technique, and beads were moved to plates containing freshly streaked bacteria every seventh day. This process was run in triplicate over the course of 56 days. Statistical analysis was conducted using SPSS v. 28 with repeated measures analysis of variance (ANOVA) and pairwise comparisons with Tukey correction. RESULTS: In experiments with C acnes, beads containing ertapenem + vancomycin and vancomycin alone formed the largest zones of inhibition over time (P < .001). In experiments with Staphylococcus, beads containing vancomycin alone formed the largest zones of inhibition over time for all 5 strains (P < .001). Zones of inhibition were 1.4x larger for C acnes than for Staphylococcus with beads containing vancomycin alone. For both C acnes and Staphylococcus, beads containing ertapenem had the strongest initial effect, preventing all bacterial growth in C acnes and almost all growth for Staphylococcus during the first week but dropping substantially by the second week. Beads containing gentamicin alone consistently created smaller zones of inhibition than beads containing vancomycin alone, with vancomycin producing zones 5.3x larger than gentamicin in C acnes and 1.3x larger in Staphylococcus (P < .001). DISCUSSION: These data suggest that for both C acnes and Staphylococcal species, CS beads impregnated with vancomycin were most effective at producing a robust antibiotic effect. Additionally, ertapenem may be a viable supplement in order to create a more potent initial antibiotic effect but is not as effective as vancomycin when used alone. Gentamicin alone was not effective in maintaining consistent and long-term antibiotic effects. These results indicate that amongst the antibiotics currently commercially available to be used with CS, vancomycin is consistently superior to gentamicin in the setting of C. acnes and CNS.

Staphylococcus aureus Adhesion and Biofilm Formation on Vascular Polyester Grafts are Inhibited In Vitro by Triclosan.

OBJECTIVE: This study evaluated Staphylococcus aureus adhesion and biofilm formation on vascular grafts, which has seldom been investigated. METHODS: Adhesion and biofilm formation capabilities of three methicillin susceptible S. aureus strains (one biofilm forming reference strain and two clinical isolates) on five different vascular biomaterials were evaluated in vitro, including polyester (P), P + gelatin (PG), P + collagen (PC), PC + silver (PCS), and PCS + triclosan (PCST). Staphylococcus aureus adhesion on grafts was evaluated after one hour of culture and biofilm formation after 24 hours of culture by four different methods: spectrophotometry after crystal violet staining; sonicate fluid culture; metabolic assay; and scanning electron microscopy (SEM). Optical density was compared using Mann-Whitney pairwise test, and bacterial counts using Wilcoxon pairwise test. RESULTS: PCST grafts were most efficient in preventing S. aureus adhesion and biofilm formation, regardless of the method used. Bacterial counts and metabolic activity were significantly lower on PCST grafts after 24 hours (5.65 vs. 9.24 [PCS], 8.99 [PC], 8.82 [PG], and 10.44 log10 CFU/mL [P]; p < .015), and only PCST grafts were bactericidal. Biofilm formation was significantly diminished on PCST grafts compared with all other grafts (p < .001). Bacterial viability and metabolic activity after 24 hours were more impaired on PG compared with PC graft, and were surprisingly higher on PCS compared with PC grafts. Biofilm biomass formed after exposure to P, PG, PC, and PCS grafts was also reduced after 24 hours of incubation with PCST grafts (p < .001). After 24 hours, few bacteria were visible by SEM on PCST grafts, whereas bacterial biofilm colonies were clearly identified on other graft surfaces. CONCLUSION: Triclosan impregnated PCST grafts appeared to interfere with S. aureus adhesion from early stages of biofilm formation in vitro. Silver impregnation was not efficient in preventing biofilm formation, and collagen coating promoted S. aureus biofilm formation more than gelatin coating.

Comparison of global decolonization efficacy with mupirocin nasal drop and chlorhexidine mouthwash in acute leukemia patients: randomized clinical trial.

PURPOSE: Neutropenic fever remains a major complication in acute leukemia. Decolonization is assumed as a promising intervention for eradicating causative agents of infection. METHODS: In this randomized clinical trial, 96 patients with acute leukemia were assigned randomly to mupirocin nasal drop 2% (n = 32), chlorhexidine mouthwash 0.2% (n = 33), and control group (n = 31). In control group, patients did not receive any medication for decolonization. All patients received treatment for 5 days (2 days prior to chemotherapy until 3 days after chemotherapy). Pharynx and nasal swabs were taken prior to the intervention and at the end of decolonization period in all groups. Antibiotic susceptibility testing was performed by the disc diffusion method in order to identify bacterial isolates. RESULTS: Bacterial recovery of both nasal and pharynx swabs was observed after global decolonization with mupirocin nasal drop. Decolonization with mupirocin significantly eradicated Coagulase-negative staphylococci (CONS) in both nasal and pharynx swabs (p-value = 0.000). Moreover, mupirocin decreased Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA) species. Chlorhexidine mouthwash significantly eradicated CONS in pharynx swabs (p-value = 0.000). In addition, both decolonization strategies decreased both antibiotic use and frequency of fever in leukemic patients. CONCLUSION: Global decolonization with mupirocin nasal drop not only eradicates both nasal and pharynx microorganisms, but also reduces antibiotic requirement and frequency of fever in patients with acute leukemia. The protocol of the present study was approved on December 2016 (registry number: IRCT20160310026998N6).

Colonization of methicillin-resistant Staphylococcus species in healthy and sick pets: prevalence and risk factors.

BACKGROUND: The characterization of staphylococcal species that colonize pets is important to maintain animal health and to minimize the risk of transmission to owners. Here, the prevalence of Staphylococcus spp. and methicillin resistance was investigated in canine and feline isolates, and risk factors of staphylococcal colonization were determined. Pets were examined and separated into four groups: (1) healthy dogs, (2) healthy cats, and (3) dogs and (4) cats with clinical signs of bacterial infections of skin, mucous membranes, or wounds. Specimens were collected by a veterinary physician from six anatomic sites (external ear canal, conjunctival sacs, nares, mouth, skin [groin], and anus). In total, 274 animals (cats n = 161, dogs n = 113) were enrolled. RESULTS: Staphylococcus species were highly diverse (23 species; 3 coagulase-positive and 20 coagulase-negative species), with the highest variety in healthy cats (19 species). The most frequent feline isolates were S. felis and S. epidermidis, while S. pseudintermedius was the most prevalent isolate in dogs. Risk factors of staphylococcal colonization included the presence of other animals in the same household, medical treatment within the last year, and a medical profession of at least one owner. Methicillin resistance was higher in coagulase-negative (17.86%) compared to coagulase-positive (1.95%) staphylococci. The highest prevalence of methicillin-resistant CoNS colonization was observed in animals kept in homes as the most common (dogs and cats). CONCLUSIONS: The association of methicillin-resistant CoNS colonization with animals most often chosen as pets, represents a high risk of transmission between them and owners. The importance of nosocomial transmission of CoNS was also confirmed. This information could guide clinical decisions during the treatment of veterinary bacterial infections. In conclusion, the epidemiologic characteristics of CoNS and their pathogenicity in pets and humans require further research.

Carriage of Staphylococcus pseudintermedius by clinically normal dogs in Canterbury, New Zealand.

AIMS: To investigate the frequency of carriage of methicillin-susceptible and methicillin-resistant Staphylococcus pseudintermedius (MRSP) in a population of clinically normal dogs within the Christchurch and wider Canterbury region, an area in which MRSP has been detected. METHODS: Buccal and perianal swabs were collected from 126 clinically normal dogs presenting at veterinary clinics in the Christchurch/Canterbury region for de-sexing or routine vaccination. S. pseudintermedius was isolated by selective culture. Isolates were tested for susceptibility to 12 antimicrobials by disc diffusion. RESULTS: S. pseudintermedius was isolated from 92/126 (73.0 (95% CI = 64.4-80.5)%) dogs, with 38/126 (30.2 (95% CI = 22.3-39.0)%) positive dogs carrying S. pseudintermedius at both sampled sites. More animals (78/126; 61.9 (95% CI = 52.8-70.4)%) had positive mouth cultures than positive perianal region cultures (52/126; 41.3 (95% CI = 32.6-50.4)%). No MRSP was isolated from clinically normal dogs. However, resistance to penicillin (106/130 (85.1%) swabs) and tetracycline (33/130 (25.4%) swabs) was seen. CONCLUSIONS: The majority of the dogs in this sample were carriers of S. pseudintermedius. However, none of these isolates were MRSP. CLINICAL RELEVANCE: While most clinically normal dogs in the studied region are likely to be carriers of S. pseudintermedius, only a small proportion, if any, are likely to be carriers of MRSP. Antibiotic stewardship practices may be important to maintain low-level circulation of drug-resistant bacterial lineages.

MICROBIOLOGICAL FEATURES OF STAPHYLOCOCCUS ASSOCIATED WITH COMPLICATIONS OF DENTAL IMPLANTATION.

OBJECTIVE: The aim: To describe microbiological features of the Staphylococcus spp. involved in complications of dental implantation. PATIENTS AND METHODS: Materials and methods: The main method was bacteriological. Indentification of the obtained isolates was done using commercially available test kits. Adhesive properties were evaluated using Brillis technique. Biofilm-forming ability was studied according to Christensen et al. Antimicrobial susceptibility testing was done following EUCAST recomendations. RESULTS: Results: There were 26 smears taken from the peri-implant area and gingival pockets of 12 patients. We obtained 38 isolates. Most of the patients were positive for Streptococcus spp. - 94% and Staphylococcus spp. - 90%. Among the representatives of Staphylococcus spp., the initial share of clinical isolates was S. aureus (34.21%) with inherent coagulase-positive properties. Coagulase-negative pathogens accounted for 65.79% of Staphylococcus spp., among them S. epidermidis, S. hominis, S. warneri were the main. All obtained isolates had typical properties, but appearance of small colonial variants of S. aureus was also recorded. Antimicrobial susceptibility testing was performed in 100% of cases. Among 13 isolates of S. aureus there were 2 cultures resistant to cefoxitin, i. e. methicillin-resistant by phenotype. Clinical isolates of S. aureus, colonizing peri-implant tissues in infectious-inflammatory complications of dental implantation, also had high adhesive and biofilm-forming properties. Clinical isolates of S. epidermidis an average ability to form biofilms. CONCLUSION: Conclusions: There is a prooved direct correlation between biofilm-forming ability and adhesive properties in highly biofilm-forming clinical isolates involved in the occurrence of purulent-inflammatory complications in peri-implant site.

Secondary Amine Pendant ß-Peptide Polymers Displaying Potent Antibacterial Activity and Promising Therapeutic Potential in Treating MRSA-Induced Wound Infections and Keratitis.

Interest in developing antibacterial polymers as synthetic mimics of host defense peptides (HPDs) has accelerated in recent years to combat antibiotic-resistant bacterial infections. Positively charged moieties are critical in defining the antibacterial activity and eukaryotic toxicity of HDP mimics. Most examples have utilized primary amines or guanidines as the source of positively charged moieties, inspired by the lysine and arginine residues in HDPs. Here, we explore the impact of amine group variation (primary, secondary, or tertiary amine) on the antibacterial performance of HDP-mimicking ß-peptide polymers. Our studies show that a secondary ammonium is superior to either a primary ammonium or a tertiary ammonium as the cationic moiety in antibacterial ß-peptide polymers. The optimal polymer, a homopolymer bearing secondary amino groups, displays potent antibacterial activity and the highest selectivity (low hemolysis and cytotoxicity). The optimal polymer displays potent activity against antibiotic-resistant bacteria and high therapeutic efficacy in treating MRSA-induced wound infections and keratitis as well as low acute dermal toxicity and low corneal epithelial cytotoxicity. This work suggests that secondary amines may be broadly useful in the design of antibacterial polymers.

Interactions between the foreign body reaction and Staphylococcus aureus biomaterial-associated infection. Winning strategies in the derby on biomaterial implant surfaces.

Biomaterial-associated infections (BAIs) are an increasing problem where antibiotic therapies are often ineffective. The design of novel strategies to prevent or combat infection requires a better understanding of how an implanted foreign body prevents the immune system from eradicating surface-colonizing pathogens. The objective of this review is to chart factors resulting in sub-optimal clearance of Staphylococcus aureus bacteria involved in BAIs. To this end, we first describe three categories of bacterial mechanisms to counter the host immune system around foreign bodies: direct interaction with host cells, modulation of intercellular communication, and evasion of the immune system. These mechanisms take place in a time frame that differentiates sterile foreign body reactions, BAIs, and soft tissue infections. In addition, we identify experimental interventions in S. aureus BAI that may impact infectious mechanisms. Most experimental treatments modulate the host response to infection or alter the course of BAI through implant surface modulation. In conclusion, the first week after implantation and infection is crucial for the establishment of an S. aureus biofilm that resists the local immune reaction and antibiotic treatment. Although established and chronic S. aureus BAI is still treatable and manageable, the focus of interventions should lie on this first period.

Characterizing biofilm formation of Staphylococcus pseudintermedius in different suture materials.

Staphylococcus pseudintermedius is the primary cause of pyoderma and surgical site infection (SSI) in dogs, and biofilm formation is the main reason for persistent SSI. The presence of biofilm in medical devices can directly impact treatment. Methicillin-resistant S. pseudintermedius (MRSP) emerged rapidly in companion animals, limiting treatment options. MRSP is a public health problem since zoonotic transmission can occur. The study seeks to evaluate biofilm formation capacity via Staphylococcus pseudintermedius collected from dogs affected by topical infections, in suture materials commonly used in companion animal surgery. We tested segments of four types of sutures. Biofilm production was measured by staining with safranin and colorimetric absorbance measurement. We calculated colony-forming units (CFUs) for each type of sutures and visualized biofilm via Scanning Electron Microscopy (SEM) images. The genes associated with biofilm formation (icaA and icaD) were identified using PCR. The colorimetric tests showed that the biofilm is most abundantly formed on the cotton sutures and polyglactin 910. The ability to form biofilm on polypropylene and nylon sutures has also been demonstrated, although at varying intensities. PCR revealed the presence of the two genes (icaA and icaD) in all the isolates. We used a positive control using a reference strain and negative control without bacteria for comparisons. Suture material allowing biofilm formation makes it difficult to prevent and treat surgical site infections. Therefore, it is important to know which suture thread is more susceptible to biofilm formation by bacteria to prevent possible secondary infections at surgical sites.

Anti-virulence properties of catechin-in-cyclodextrin-in-phospholipid liposome through down-regulation of gene expression in MRSA strains.

Methicillin resistant Staphylococcus aureus (MRSA) is a prime pathogen responsible for various infections in human beings. Expression of virulence factors is a biggest challenge in MRSA, which results in failure of conventional antibiotic therapy. In connection to the search for natural and safe anti-virulence compounds, the present study focused to evaluate the anti-virulence potential of catechin-in-cyclodextrin-in-phospholipid liposome (CCPL) on MRSA strains. CCPL inhibited young biofilm (64.15-72.70%) as well degraded mature biofilm (55.60-63.65%) at ½ and » MIC doses, which was further confirmed by scanning electron microscopy and confocal laser scanning microscope studies. CCPL was capable enough to modify the surface hydrophobicity (40.26-48.59%), reduce the EPS production (1.71-2.25 folds) and bacterial motility. In addition, CCPL inhibited the synthesis of virulence factors like slime production (0.40-0.50 folds), DNase production, hemolytic activity (28.08-49.07%), proteolytic production (14.65-18.04%), lipase production, autolysis and cell auto-aggregation. CCPL prevented the staphyloxanthin production and thereby increased the susceptibility of MRSA strains towards H2O2. Further, CCPL significantly down-regulated the virulence genes (agrA, agrC, clfA, clfB, fnbA, fnbB, icaA, icaD, hla, hld, rna III, atlA, sarA, sigB & geh). Thus, the results of present study revealed that the CCPL can effectively reduce the virulence properties and its application could inhibit the pathogenicity and also prevents the development of drug-resistance in MRSA strains.

Evaluation of ligand modified poly (N-Isopropyl acrylamide) hydrogel for etiological diagnosis of corneal infection.

Corneal ulcers, a leading cause of blindness in the developing world are treated inappropriately without prior microbiology assessment because of issues related to availability or cost of accessing these services. In this work we aimed to develop a device for identifying the presence of Gram-positive or Gram-negative bacteria or fungi that can be used by someone without the need for a microbiology laboratory. Working with branched poly (N-isopropyl acrylamide) (PNIPAM) tagged with Vancomycin, Polymyxin B, or Amphotericin B to bind Gram-positive bacteria, Gram-negative bacteria and fungi respectively, grafted onto a single hydrogel we demonstrated specific binding of the organisms. The limit of detection of the microbes by these polymers was between 10 and 4 organisms per high power field (100X) for bacteria and fungi binding polymers respectively. Using ex vivo and animal cornea infection models infected with bacteria, fungi or both we than demonstrated that the triple functionalised hydrogel could pick up all 3 organisms after being in place for 30 min. To confirm the presence of bacteria and fungi we used conventional microbiology techniques and fluorescently labelled ligands or dyes. While we need to develop an easy-to-use either a colorimetric or an imaging system to detect the fluorescent signals, this study presents for the first time a simple to use hydrogel system, which can be applied to infected eyes and specifically binds different classes of infecting agents within a short space of time. Ultimately this diagnostic system will not require trained microbiologists for its use and will be used at the point-of-care.

Mycotic Aneurysm of Internal Carotid Artery Secondary to Livestock-associated Methicillin-resistant Staphylococcus Aureus Clonal Complex CC398.

The aim of this article is to present a case of mycotic aneurysm of internal carotid artery secondary to livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) treated with resection and common-to-internal carotid artery bypass with autologous vein graft in a male pig farmer. A 69-year-old man, pig farmer, with recent dental extraction was admitted with a right cervical pulsatile mass, dysphonia, pain, leukocytosis and elevated C-reactive protein (CRP). Ultrasonography (US) and computed tomography angiography (CTA) showed a 3.9 × 4.5 cm mycotic aneurysm of right internal carotid artery with hypermetabolic uptake in positron emission tomography (PET) scan. Resection of the mycotic aneurysm and a common-to-internal carotid artery bypass with major saphenous vein graft were performed. LA-MRSA clonal complex (CC) 398 was detected in intraoperative samples and antibiotic therapy was changed according to antibiogram. Patient was discharged at the seventh postoperative day and received antibiotic therapy for 6 weeks. US 12 months later showed patency of the bypass without collections. Mycotic aneurysms of internal carotid artery are very infrequent. MRSA isolation is rare, and to the best of our knowledge this is the first case caused by multi-drug resistant LA-MRSA CC398. The treatment includes mycotic aneurysm resection and reconstruction with venous graft bypass plus intensive antibiotic therapy.

New 1,3,4-oxadiazole compound with effective antibacterial and antibiofilm activity against Staphylococcus aureus.

Staphylococcus aureus is one of the main aetiological agents causing food-borne diseases. Some strains produce enterotoxins responsible for food poisoning. In addition, they can form biofilms on several surfaces such as plastics, glass and stainless steel making it difficult to eliminate them. The present study evaluated, for the first time, the antibacterial and antibiofilm activities of the synthetic compound LMM6 against S. aureus. The minimum inhibitory concentration was 0·97, 1·95 and 1·95 µg ml-1 against S. aureus ATCC 25923, S. aureus 629/94 and S. aureus FRI S-6, respectively. The time-kill curves showed that 96 h treatment with LMM6 reduced approximately 4 log CFU per ml at all tested concentrations. Furthermore, LMM6 reduced S. aureus preformed biofilm by approximately 1 log CFU per cm2 . During biofilm formation, a reduction of approximately 4 log CFU per cm2 was observed. LMM6 also reduced biofilm biomass during (~60%) and after biofilm formation (~25 to 45%), as shown by the crystal violet assay. Based on these results, we conclude that LMM6 exhibits antibacterial and antibiofilm activity and may be an innovative synthetic molecule for controlling S. aureus.

Alveolar osteitis associated with methicillin-resistant Staphylococcus epidermidis.

A critical point in dentistry is the empiric prescription of broad-spectrum antibiotics that could increase the levels of antimicrobial resistance. Alveolar osteitis is one of the most common post-op- erative complications in which antibiotic use is controversial. A 35-year-old female, with pain in the right mandibular region and treated with cefixime, was diagnosed with cracked tooth syndrome and pulpitis. The tooth was extracted and a massive purulent bleeding drainage was observed. Irrigation of the socket and a new therapy with azithromycin were done. Bacteriological analysis, a specific mecA gene PCR for the methicillin resistance, and the antimicrobial susceptibility test were per- formed on the bacterial isolate. A Staphylococcus epidermidis isolate was methicillin-resistant and showed resistance to erythromycin, azithromycin, clarithromycin, and sulfamethoxazole + trimeth- oprim. After 7 days, intraoral examination showed a complete resolution. The aim of this report is to suggest that systemic antibiotics may provide insufficient efficacy during alveolar osteitis, especially when caused by a multidrug-resistant organism.

Implantable drug delivery systems for the treatment of osteomyelitis.

Osteomyelitis is an infection of the bone tissue and bone marrow which is becoming increasingly difficult to treat due to the infection causing pathogens associated. Staphylococcus aureus is one of the main bacteria that causes this infection, which has a broad spectrum of antibiotic resistance making it extremely difficult to treat. Conventional metal implants used in orthopedic applications often have the drawback of implant induced osteomyelitis as well as the requirement of a second surgery to remove the implant once it is no longer required. Recently, attention has been focused on the design and fabrication of biodegradable implants for the treatment of bone infection. The main benefit of biodegradable implants over polymethylmethacrylate (PMMA) based non-degradable systems is that they do not require a second surgery for removal and so making degradable implants safer and easier to use. The main purpose of a biodegradable implant is to provide the necessary support and conductivity to allow the bone to regenerate whilst themselves degrading at a rate that is compatible with the rate of formation of new bone. They must be highly biocompatible to ensure there is no inflammation or irritation within the surrounding tissue. During this review, the latest research into antibiotic loaded biodegradable implants will be explored. Their benefits and drawbacks will be compared with those non-degradable PMMA beads, which is the stable material used within antibiotic loaded implants. Biodegradable implants most frequently used are based on biodegradable natural and synthetic polymers. Implants can take the form of many different structures; the most commonly fabricated structure is a scaffold. Other structures that will be explored within this review are hydrogels, nanoparticles and surface coatings, all with their own benefits/drawbacks.

Evidence of cross-contamination of waste workers and transmission of antimicrobial resistance genes by coagulase-negative Staphylococcus isolated from dental solid waste: an intriguing study.

The aim of this study was to phenotypically and genotypically identify coagulase-negative Staphylococcus (CoNS) recovered from the nostrils of waste workers and from dental waste; 135 strains were recovered and S. epidermidis was the prevailing species. Genetic similarity (100%) was observed between the two S. epidermidis isolated from different employees on the same shift and 85% similarity between the S. epidermidis recovered from an employee's nostril and from waste. The mecA gene was found in 20 CoNS, and 20% were also found to possess the vanA gene. The blaZ gene was detected in 46.7%, and the icaA (34.8%), B and C genes (11.8% each). Our findings emphasized the biological risk to which waste workers are exposed and unprecedently confirms that it was possible to recover genetically identical bacterial species from waste and from workers' nostrils. It is important to highlight that this risk is raised by the detection of relevant antimicrobial resistance genes. The results also suggest that effective measures to correctly manage waste and promote the rational use of antimicrobials should be adopted.

Evaluation of Staphylococcus aureus and Candida albicans biofilms adherence to PEEK and titanium-alloy prosthetic spine devices.

BACKGROUND: Titanium and polyether-ether-ketone (PEEK) interbody cages are commonly used for spine fusion. Few data are known about bacterial and yeast biofilms formation in these implants. The aim of this study was to compare Staphylococcus aureus and Candida albicans biofilm formation in the surface of two different interbody devices used routinely in spine surgery. METHODS: Six bodies of proof specimens of PEEK and titanium alloy were used for microbiological tests, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Experimental biofilm was produced with Staphylococcus aureus and Candida albicans, followed by quantitative analysis of planktonic cells and sessile cells. The comparison between the medians of biofilm quantification between the two models was performed using the Mann-Whitney test and considered the statistical difference for a p < 0.05. RESULTS: In the S. aureus model, in both planktonic and sessile cell counts, titanium-alloy samples showed lower values for colony forming units per milliliter (UFC/mL) (p < 0.05). The evaluation through the optic density of planktonic and sessile cells showed lower values in the titanium-alloy samples, however, only statistically significant in planktonic cell count (p < 0.05). The count of planktonic yeast cells in PEEK was similar to titanium-alloy samples, while the count of sessile yeast cells in titanium alloy was lower when compared to PEEK (p < 0.05). CONCLUSION: Titanium-alloy models were associated with less staphylococcal and Candida biofilm formation when compared with PEEK.

Quantitative flow chamber system for evaluating in vitro biofilms and the kinetics of S. aureus biofilm formation in human plasma media.

BACKGROUND: It has been well established that biofilm formation on orthopaedic implants is a critical event in the pathogenesis of orthopaedic infections, yet the natural history of this process with respect to bacterial adhesion, proliferation, and glycocalyx matrix production remains poorly understood. Moreover, there are no quantitative methods yet available to assess the differences in biofilm formation between different bacterial strains or implant materials. Consequently, this study aimed to investigate the natural history of S. aureus in in vitro biofilm formation in human plasma media using a flow chamber system. Bioluminescent S. aureus strains were used to better understand the bacterial growth and biofilm formation on orthopaedic materials. Also, the effects of human plasma media were assessed by loading the chamber with Tryptic Soy Broth with 10% human plasma (TSB + HP). RESULTS: Scanning electron microscopy (SEM) was utilized to assess the morphological appearance of the biofilms, revealing that S. aureus inoculation was required for biofilm formation, and that the phenotypes of biofilm production after 24 h inoculation with three tested strains (SH1000, UAMS-1, and USA300) were markedly different depending on the culture medium. Time course study of the bioluminescence intensity (BLI) and biofilm production on the implants due to the UAMS-1 and USA300 strains revealed different characteristics, whereby UAMS-1 showed increasing BLI and biofilm growth until peaking at 9 h, while USA300 showed a rapid increase in BLI and biofilm formation at 6 h. The kinetics of biofilm formation for both UAMS-1 and USA300 were also supported and confirmed by qRT-PCR analysis of the 16S rRNA gene. Biofilms grown in our flow chamber in the plasma media were also demonstrated to involve an upregulation of the biofilm-forming-related genes icaA, fnbA, and alt. The BLI and SEM results from K-wire experiments revealed that the in vitro growth and biofilm formation by UAMS-1 and USA300 on stainless-steel and titanium surfaces were virtually identical. CONCLUSION: We demonstrated a novel in vitro model for S. aureus biofilm formation with quantitative BLI and SEM outcome measures, and then used this model to demonstrate the presence of strain-specific phenotypes and its potential use to evaluate anti-microbial surfaces.

Restoring Endogenous Repair Mechanisms to Heal Chronic Wounds with a Multifunctional Wound Dressing.

Current treatment of chronic wounds has been critically limited by various factors, including bacterial infection, biofilm formation, impaired angiogenesis, and prolonged inflammation. Addressing these challenges, we developed a multifunctional wound dressing-based three-pronged approach for accelerating wound healing. The multifunctional wound dressing, composed of nanofibers, functional nanoparticles, natural biopolymers, and selected protein and peptide, can target multiple endogenous repair mechanisms and represents a promising alternative to current wound healing products.