: This study aimed to evaluate the antimicrobial activity of two different formulations of bioglass BAG-S53P4 against multiresistant microorganisms involved in bone infections, and the capability of ...bioglass to select for resistance.
Antibacterial activity was evaluated by means of killing curves. The ability to select for resistant bacteria was evaluated by subculturing microorganisms in serial dilutions of bioglass. Scanning electron microscope acquisitions were conducted to evaluate bioglass-induced morphology changes.
BAG-S53P4 formulations display a high antimicrobial activity and do not seem to select for resistance. Scanning electron microscopy analysis showed cell shrinkage and membrane damage after exposure to bioglass.
BAG-S53P4 has a significant potential as bone substitute for the treatment of infections caused by multiresistant microorganisms.
The treatment of bone and joint infections is challenging due to the presence of bacterial biofilm and the increasing emergence of multiresistant strains. BAG-S53P4 is a bone substitute that is ...characterized by osteoconductive and antimicrobial properties. The aim of this study was to assess the effectiveness of BAG-S53P4 against biofilm produced in vitro by multiresistant bacterial strains.
Multiresistant Staphylococcus epidermidis, Acinetobacter baumannii and Klebsiella pneumoniae isolated from bone and joint infections were used in this study. Titanium discs covered by bacterial biofilm were incubated with BAG-S53P4 or inert glass as a control. The amount of biofilm on each titanium disc was evaluated after 48 h of incubation by means of confocal laser scanning microscopy.
Significantly lower total biomass volumes were observed for all strains after treatment with BAG-S53P4 when compared with controls. Moreover, the percentage of dead cells was significantly higher in treated samples than in controls for all the tested strains.
BAG-S53P4 is able to reduce the biofilm produced by multiresistant S. epidermidis, A. baumannii and K. pneumoniae on titanium substrates in vitro, probably by interfering with cell viability. Owing to its osteoconductive, antibacterial and antibiofilm properties, the use of BAG-S53P4 may be a successful strategy for the treatment of bone and prosthetic joint infections.
Implant-related infections are associated with impaired bone healing and osseointegration. In vitro antiadhesive and antibacterial properties and in vivo antiinflammatory effects protecting against ...bone loss of various formulations of vitamin E have been demonstrated in animal models. However, to the best of our knowledge, no in vivo studies have demonstrated the synergistic activity of vitamin E in preventing bacterial adhesion to orthopaedic implants, thus supporting the bone-implant integration.
The purpose of this study was to test whether a vitamin E phosphate coating on titanium implants may be able to reduce (1) the bacterial colonization of prosthetic implants and (2) bone resorption and osteomyelitis in a rat model of Staphylococcus aureus-induced implant-related infection.
Twelve rats were bilaterally injected in the femurs with S aureus UAMS-1-Xen40 and implanted with uncoated or vitamin E phosphate-coated titanium Kirschner wires without local or systemic antibiotic prophylaxis. Eight rats represented the uninfected control group. A few hours after surgery, two control and three infected animals died as a result of unexpected complications. With the remaining rats, we assessed the presence of bacterial contamination with qualitative bioluminescence imaging and Gram-positive staining and with quantitative bacterial count. Bone changes in terms of resorption and osteomyelitis were quantitatively analyzed through micro-CT (bone mineral density) and semiquantitatively through histologic scoring systems.
Six weeks after implantation, we found only a mild decrease in bacterial count in coated versus uncoated implants (Ti versus controls: mean difference MD, -3.705; 95% confidence interval CI, -4.416 to -2.994; p < 0.001; TiVE versus controls: MD, -3.063; 95% CI, -3.672 to -2.454; p < 0.001), whereas micro-CT analysis showed a higher bone mineral density at the knee and femoral metaphysis in the vitamin E-treated group compared with uncoated implants (knee joint: MD, -11.88; 95% CI, -16.100 to -7.664; p < 0.001 and femoral metaphysis: MD, -19.87; 95% CI, -28.82 to -10.93; p < 0.001). We found decreased osteonecrosis (difference between medians, 1.5; 95% CI, 1-2; p < 0.002) in the infected group receiving the vitamin E-coated nails compared with the uncoated nails.
These preliminary findings indicate that vitamin E phosphate implant coatings can exert a protective effect on bone deposition in a highly contaminated animal model of implant-related infection.
The use of vitamin E coatings may open new perspectives for developing coatings that can limit septic loosening of infected implants with bacterial contamination. However, a deeper insight into the mechanism of action and the local release of vitamin E as a coating for orthopaedic implants is required to be used in clinics in the near future. Although this study cannot support the antimicrobial properties of vitamin E, promising results were obtained for bone-implant osseointegration. These preliminary results will require further in vivo investigations to optimize the host response in the presence of antibiotic prophylaxis.
Abstract Background Prosthetic joint infections (PJI) are still a major complication of hip and knee replacements. Identification of the causative pathogens and knowledge of their antibiotic ...susceptibilities are essential for the management of these infections. The main purpose of the study was to identify and compare the causative bacteria of prosthetic knee and hip joint infections in a reference Italian orthopaedic center and to characterize antibiotic resistance profiles of bacteria involved. Methods Data from 429 patients with diagnosis of PJI were collected from January 2013 to June 2015: 229 presented a hip and 200 a knee prosthesis infection. Prostheses and periprosthetic tissues were treated with dithiothreitol before plating onto different media and broths. Identification and antimicrobial susceptibility testing were carried out by Vitek2 Compact (BioMerieux). Results There was not a substantial difference in the etiology of hip and knee PJI: staphylococci were the most frequently isolated bacteria in both groups, followed by Enterobacteriaceae and Propionibacterium acnes . Staphylococci showed a high rate of methicillin resistance (144/341) and a worrying frequency of isolates were resistant to teicoplanin (9 %). Only 8.3% of Enterobacteriaceae produced extended-spectrum beta-lactamases, whereas the rate of carbapenemase-producing bacteria was not significant. Conclusions We observed similar etiology of hip and knee PJIs. Nevertheless, bacteria isolated from knee showed higher resistance rates to glycopeptides and fluoroquinolones if compared with those isolated from the hip. The reason for this difference remains to be elucidated in future studies.
Skin and soft tissue infections
are a major therapeutic challenge for clinicians. The emergence of pathogens with decreased susceptibility to available therapies has become an emerging problem often ...associated with treatment failure. Hence, there is an urgent need for novel broad-spectrum antimicrobial agents. The purpose of this study was to assess the feasibility of chlorquinaldol as an alternative approach to currently used topical antibiotics for the treatment of skin and soft tissue infections. The activity of chlorquinaldol was investigated against a collection of bacterial isolates responsible for skin infections, including strains resistant to fusidic acid and gentamicin. After determination of MIC and MBC, time-kill experiments were carried out by counting colonies grown after 0, 3, 6, 9, 24, and 48 h of incubation with concentrations equal to ¼×, ½×, 1×, 2×, and 4× MIC of chlorquinaldol, gentamicin, or fusidic acid. Staphylococci resulted the Gram-positives most sensitive to chlorquinaldol, with MIC-values ranging from 0.016 to 0.5 mg/L. A lower activity was observed against Gram-negative bacteria, with 77% of the isolates being inhibited at concentrations ranging from 128 to 512 mg/L. Generally, in time-kill studies, chlorquinaldol showed a bactericidal activity at the higher concentrations (2×, 4× MIC) after 24-48 h of incubation. In conclusion, chlorquinaldol may represent a valuable alternative to conventional topical antibiotics for the treatment of skin and soft tissue infections.
Background
Odontogenic sinusitis and sinonasal complications of dental disease or treatment (SCDDT) play a relevant, often underappreciated role in paranasal sinus infections. Treating SCDDT patients ...requires tailored medical and surgical approaches in order to achieve acceptable success rates. These approaches differ from common rhinogenic sinusitis treatment protocols mostly because of the different etiopathogenesis. Our study comprehensively evaluated microbiology and antibiotic resistance in SCDDT patients and compared findings with a control group of patients affected by rhinogenic sinusitis.
Methods
We performed microbiological sampling during surgery on 28 patients with SCDDT and 16 patients with chronic rhinosinusitis with nasal polyps (CRSwNP). Colonies were isolated, Gram‐stained, and the species identified using classic biochemical methods. These results were confirmed by DNA pyrosequencing, and then the resistance profile of each SCDDT isolate to various antibiotics was tested.
Results
Microbial growth was observed in all SCDDT patients, whereas samples from 60% of patients in the control group failed to yield any bacterial growth (p < 0.001). Anaerobes grew in 14% of SCDDT patients as compared to 7% of CRSwNP patients (p = 0.42). Of the isolates from SCDDT patients, 70% were susceptible to amoxicillin/clavulanate, whereas all isolates were susceptible to levofloxacin, teicoplanin, and vancomycin. Of the staphylococci identified, 80% were capable of producing beta‐lactamase.
Conclusion
Given the extent of microbiological contamination within the maxillary sinus of SCDDT patients, these infections should be regarded as a different class of conditions from rhinogenic sinusitis. Our findings support the need for different approaches in the treatment of SCDDT patients.
This work aimed to investigate the ability of different formulations of bioactive glass (BAG)-S53P4 to interfere with bacterial biofilm produced on prosthetic material by methicillin-resistant ...Staphylococcus aureus and multi-drug-resistant Pseudomonas aeruginosa.
Antibiofilm activity of three formulations of bioglass was assessed at different time points through two different analyses: Crystal Violet and confocal laser scanning microscopy assays.
Significant differences in the whole biofilm were observed between BAG-S53P4-treated and control samples, while no marked changes in antibiofilm activity were observed among the tested formulations. Data from colorimetric assay were confirmed by confocal laser scanning microscopy analysis, which evidenced the significant reduction in biomass and a decrease of total cell volume when both S. aureus and P. aeruginosa biofilms were treated with BAG-S53P4.
BAG-S53P4 can be considered as an excellent adjuvant in the treatment of prosthetic infections related to biofilm.
Abstract Background Prosthetic implants, periprosthetic and osteoarticular tissues are specimens of choice for diagnosis of bone and joint infections. Homogenization is considered the best procedure ...for treatment of tissues samples, but, it is not always performed in all laboratories. Dithiothreitol (DTT) has been proposed as an alternative treatment to sonication for microbiological diagnosis of prosthetic joint infections. In this study, the applicability of DTT treatment for processing of periprosthetic and osteoarticular tissues for diagnosis of bone and joint infections was evaluated and compared with normal saline solution treatment. Methods Periprosthetic tissue samples were collected from 70 consecutive patients (25 infected and 45 not infected). For each patient, samples from the same site were randomly allocated to DTT or saline treatment. Treated samples were centrifuged at 3000 rpm for 10 minutes. Aliquots from the concentrated samples were plated on agar plates and inoculated in broths. Sensitivity and specificity were calculated for each treatment. Results Microbial growth was observed in samples from 14 and 11 infected patients after DTT and saline treatments, respectively. Concordance between the 2 methods was observed in the 85.7% of cases. Sensitivity was 88.0% for DTT and 72.0% for saline. Specificity was 97.8% and 91.1% for DTT and saline, respectively. Treatment with DTT showed higher sensitivity and specificity with respect to the method routinely used in our laboratory. Conclusion DTT treatment may be considered a practicable strategy for microbiological analysis of tissues for diagnosis of bone and joint infections.
Synovial fluid analysis for diagnosis of prosthetic joint infections has gained increasing interest in the recent past when markers more specific for these infections than the serum ones have been ...identified. Despite the important steps forward, identification of a gold standard has not yet been identified. In this study, usefulness of alpha defensin, leukocyte esterase, C-reactive protein (CRP), and white blood cells (WBCs) in synovial fluids alone and in combination for diagnosis of prosthetic joint infection was evaluated. Synovial fluids from 32 infected and 34 not infected patients were analyzed. Sensitivity, specificity, positive and negative predictive values, diagnostic accuracy, and receiver-operating characteristic (ROC) curves were calculated for each parameter. Moreover, combination of coupled variables was also evaluated by logistic regression analysis. Sensitivity of alpha defensin, CRP, leukocyte count, and leukocyte esterase were 84.4%, 87.5%, 93.7%, and 93.8%, respectively. Specificity was 91.2% for leukocyte counts, 94.1% for alpha defensin, 97.0% for CRP, and 97.1% for leukocyte esterase. Diagnostic accuracy was 89.4% for alpha defensin, 92.4% for WBC counts and CRP, and 95.5% for leukocyte esterase. No statistical differences were observed in area under the curve (AUC) of the ROC curves of alpha defensin, CRP, and leukocyte counts. Logistic regression analysis applied to a model comprising all the variables showed an AUC higher than AUC of coupled variables. In conclusion, results of this study confirm the high sensitivity and specificity of synovial leukocyte esterase for diagnosis of prosthetic joint infection, also suggesting the need to assess a panel of markers to optimize diagnosis of these infections.
Background
Sonication and scraping of infected prostheses usually are used to improve diagnosis of prosthetic infections, reducing false negatives. Chemical methods that reduce biofilms also may ...allow higher levels of detection.
Questions/Purposes
We therefore asked: (1) Do dithiothreitol (DTT) and N-acetylcysteine (NAC) remove bacteria from biofilm formed on prosthetic materials? (2) Is bacterial recovery affected by differing DTT and NAC concentrations and incubation times? (3) Do treatments with DTT and NAC detach the same amounts of bacteria from biofilm on prosthetic materials as sonication and scraping? (4) Are these methods reproducible?
Methods
We treated polyethylene and titanium discs covered by biofilm formed by
Pseudomonas aeruginosa
and
Staphylococcus aureus
with DTT or NAC solutions at different concentrations for different times. We compared colony counts of
S aureus
,
P aeruginosa
,
Staphylococcus epidermidis
and
Escherichia coli
after treatment with NAC, DTT, sonication and scraping. We determined colony counts after treatment of biofilm formed by one strain of
S aureus
and one of
P aeruginosa
on five discs of each material analyzed on the same day and on five discs analyzed on five consecutive days.
Results
Mean colony counts (LogCFU/mL) obtained after treatment with 1 g/L DTT for 15 minutes (5.3) were similar to those after sonication (4.9) and greater than those obtaining by scraping (3.4) and treatment with 2 g/L NAC for 30 minutes (1.9). DTT and sonication showed good reproducibility.
Clinical Relevance
Our data suggest that treatment of prostheses with DTT may be a reasonable alternative to sonication to improve detection of biofilm-associated bacteria and supplement conventional laboratory culturing techniques for diagnosing periprosthetic infections.
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