Sustainable Antibacterial and Anti-Inflammatory Silk Suture with Surface Modification of Combined-Therapy Drugs for Surgical Site Infection.

Silk sutures with antibacterial and anti-inflammatory functions were developed for sustained dual-drug delivery to prevent surgical site infections (SSIs). The silk sutures were prepared with core-shell structures braided from degummed silk filaments and then coated with a silk fibroin (SF) layer loaded with berberine (BB) and artemisinin (ART). Both the rapid release of drugs to prevent initial biofilm formation and the following sustained release to maintain effective concentrations for more than 42 days were demonstrated. In vitro assays using human fibroblasts (Hs 865.Sk) demonstrated cell proliferation on the materials, and hemolysis was 2.4 ± 0.8%, lower than that required by ISO 10993-4 standard. The sutures inhibited platelet adhesion and promoted collagen deposition and blood vessel formation. In vivo assessments using Sprague-Dawley (SD) rats indicated that the coating reduced the expression of pro-inflammatory cytokines interleukin-10 (IL-10) and tumor necrosis factor-α (TNF-α), shortening the inflammatory period and promoting angiogenesis. The results demonstrated that these new sutures exhibited stable structures, favorable biocompatibility, and sustainable antibacterial and anti-inflammatory functions with potential for surgical applications.

Predicting the disaster - The role of CRP in acetabular surgery.

OBJECTIVES: Acetabular fractures represent a complex surgical challenge. Given the heterogenous fracture pattern, the patient characteristics and spectrum of complications demand individual solutions. Surgical site infections (SSI) threaten osteosynthesis, and early detection of them and treatment remain crucial. What is the value of postoperative C-reactive protein (CRP) in this group of patients as well as its normal course? DESIGN & METHODS: 115 patients with isolated fractures of the acetabulum were retrospectively evaluated. CRP, white blood cell count (WBC) and fracture patterns as well as patient characteristics were assessed for 20 days following operative fixation of the acetabular fracture (n = 71) and in fractures that were managed conservatively (n = 44). RESULTS: Twelve patients suffered an infectious complication. With a one-phase decay, 70.55% of the variance of postoperative CRP kinetics was predicted. To anticipate maximum CRP as well as an infection, the preoperative CRP represented the best prognostic parameter. To predict an infection, the single variable "peak CRP value above 100 mg/l" resulted in a sensitivity and specificity of 91.67% and 36.21%, respectively. Combining a second peak of CRP with maximum CRP and day 5 CRP value for receiver-operating characteristic (ROC) analysis resulted in 83.3% and 88.1%, respectively. CONCLUSIONS: Predicting surgical site infections after an acetabular fracture is most predictive when analyzing the maximum overall CRP, the second peak and the CRP after day 5. With a combination of these parameters, a sensitivity and specificity of 83.3% and 88.1% to detect an infection was achieved.

Study of Inflammatory and Infection Markers in Periprosthetic Fluid: Correlation with Blood Analysis in Retrospective and Prospective Studies.

BACKGROUND: Surgical site infection represents the most severe complication in prosthetic breast reconstruction. Risk profiling represents a useful tool for both clinicians and patients. MATERIALS AND METHODS: In our hospital, 534 breast reconstructions with tissue expander implants, in 500 patients, were performed. Several clinical variables were collected. In our study, we evaluated the different inflammatory markers present in the periprosthetic fluid and we compared them with the ones present in plasma. RESULTS: The surgical site infection rate resulted to be 10.5%, and reconstruction failed in 4.5% of the cases. The hazard ratio for complications was 2.3 in women over 60 (CI: 1.3-4.07; p = 0.004), 2.57 in patients with expander volume ≥ 500 cc (CI: 1.51-4.38; p < 0.001), 2.14 in patients submitted to previous radiotherapy (CI: 1.05-4.36; p < 0.037), and 1.05 in prolonged drain use (CI: 1.03-1.07; p < 0.001). 25-OH, PCT, and total protein were less concentrated, and ferritin and LDH were more concentrated in the periprosthetic fluid than in plasma (p < 0.001). CRP (p = 0.190) and ß-2 microglobulin (p = 0.344) did not change in the two fluids analyzed. PCT initial value is higher in patients who underwent radiotherapy, and it could be related to the higher rate of their postoperative complications. Patients with a tissue expander with a volume ≥ 500 cc show an increasing trend for CRP in time (p = 0.009). CONCLUSIONS: Several risk factors (prolonged time of drains, age older than 60 years, and radiotherapy) have been confirmed by our study. The study of markers in the periprosthetic fluid with respect to their study in plasma could point toward earlier infection detection and support early management.

Immunopathogenesis of Craniotomy Infection and Niche-Specific Immune Responses to Biofilm.

Bacterial infections in the central nervous system (CNS) can be life threatening and often impair neurological function. Biofilm infection is a complication following craniotomy, a neurosurgical procedure that involves the removal and replacement of a skull fragment (bone flap) to access the brain for surgical intervention. The incidence of infection following craniotomy ranges from 1% to 3% with approximately half caused by Staphylococcus aureus (S. aureus). These infections present a significant therapeutic challenge due to the antibiotic tolerance of biofilm and unique immune properties of the CNS. Previous studies have revealed a critical role for innate immune responses during S. aureus craniotomy infection. Experiments using knockout mouse models have highlighted the importance of the pattern recognition receptor Toll-like receptor 2 (TLR2) and its adaptor protein MyD88 for preventing S. aureus outgrowth during craniotomy biofilm infection. However, neither molecule affected bacterial burden in a mouse model of S. aureus brain abscess highlighting the distinctions between immune regulation of biofilm vs. planktonic infection in the CNS. Furthermore, the immune responses elicited during S. aureus craniotomy infection are distinct from biofilm infection in the periphery, emphasizing the critical role for niche-specific factors in dictating S. aureus biofilm-leukocyte crosstalk. In this review, we discuss the current knowledge concerning innate immunity to S. aureus craniotomy biofilm infection, compare this to S. aureus biofilm infection in the periphery, and discuss the importance of anatomical location in dictating how biofilm influences inflammatory responses and its impact on bacterial clearance.

Accelerative effect of topical Zataria multiflora essential oil against infected wound model by modulating inflammation, angiogenesis, and collagen biosynthesis.

CONTEXT: Zataria multiflora Boiss (Lamiaceae) essential oil (ZME) is believed to be a bactericide herbal medicine and might alleviate negative effects of infection. OBJECTIVE: This study evaluates the effects of an ointment prepared from ZME (ZMEO) on infected wounds. MATERIALS AND METHODS: A full-thickness excisional skin wound was surgically created in each mouse and inoculated with 5 × 107 suspension containing Pseudomonas aeruginosa and Staphylococcus aureus. The BALB/c mice (n = 72) were divided into four groups: (1) negative control that received base ointment (NCG), (2) positive control that daily received Mupirocin® (MG), (3) therapeutic ointment containing 2% ZMEO and (4) therapeutic ointment containing 4% ZMEO, for 21 days. Wound contraction, total bacterial count, histopathological parameters, antioxidant activity, qRT-PCR analysis for expression of IL-1ß, TNF-α, VEGF, IGF-1, TGF-ß, IL-10, and FGF-2 mRNA levels were assessed on days 3, 7, and 14 following the wounding. RESULTS: Topical administration of ZMEO significantly decreased the total bacterial count and wound area and also expression of IL-1ß and TNF-α compared to the control groups (p < 0.05) in all days. This could also increase significantly the expression of TGF-ß, IL-10 IGF-1, FGF-2, and VEGF, and also angiogenesis, fibroblasts, fibrocytes, epithelialization ratio, and collagen deposition and improve antioxidant status compared to the control group (p < 0.05). DISCUSSION AND CONCLUSION: ZMEO accelerated the healing process of infected wounds by shortening the inflammatory factors and increasing proliferative phase. Applying ZMEO only and/or in combination with chemical agents for the treatment of wound healing could be suggested.

The Diagnostic Value of Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography for the Detection of Surgical Site Infection after Spine Surgery.

STUDY DESIGN: Retrospective case series. OBJECTIVE: The purpose of this study was to assess the diagnostic yield of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) for surgical site infection (SSI) after spine surgery. SUMMARY OF BACKGROUND DATA: Diagnosis of SSI in the spine based on F-18 FDG PET/CT requires experienced nuclear medical physicians for a detailed analysis of F-18 FDG distribution pattern. It has also been reported that increases in the maximal standardized uptake values of F-18 FDG (SUVmax) closely correlated with SSI, suggesting potential of more objective and quantitative diagnosis. METHODS: We assessed the diagnostic yield of F-18 FDG PET/CT (pattern-based diagnosis by nuclear medical physicians and SUVmax-based diagnosis) for SSI in 52 subjects who underwent spine surgery. The 52 subjects included 11 nonimplant and 41 implant cases. F-18 FDG PET/CT was performed in 33 and 19 cases in early (≤12 weeks after the surgery) and late (>12 weeks) phases, respectively. The final diagnosis of SSI was based on the results of pathogen identification, plain radiography, and CT and/or magnetic resonance imaging or response to antibiotics and/or reoperation. RESULTS: SUVmax-based diagnosis was performed with a cut off value of 5.0 as determined by receiver operating characteristic analysis. Both pattern-based and SUVmax-based diagnoses demonstrated excellent diagnostic yields with high sensitivity (97% and 90%), specificity (100% and 100%), and accuracy (98% and 94%). High diagnostic yields (accuracy of ≥90%) were consistently observed irrespective of presence or absence of implantation or interval between surgery and F-18 FDG PET/CT. CONCLUSION: F-18 FDG PET/CT can be the procedure of choice for investigation of SSI in the spine when other imaging fails to provide a definitive diagnosis.Level of Evidence: 4.

Alteration of gene expression in mice after glaucoma filtration surgery.

To clarify the early alterations of gene expression using a mouse model of glaucoma filtration surgery, we carried out microarray expression analysis. Using BALB/c mice, a filtration surgery model was made by incision of the limbal conjunctiva, followed by the insertion of a 33G needle tip into the anterior chamber, and 11-0 nylon sutures. Subgroups of mice were treated intraoperatively with 0.4 mg/ml mitomycin-C (MMC). At day 3 after surgery the bleb was maintained. The bleb region tissue was sampled 3 days after the filtration surgery, and gene expression analysis was carried out using a mouse Agilent 8 × 60 K array. We found 755 hyperexpressed transcripts in the bleb region compared to control conjunctiva. The hyperexpressed transcripts included epithelial cell metaplasia-related (Il1b, Krt16, Sprr1b), inflammation-related (Ccl2, Il6) and wound healing-related (Lox, Timp1) genes. We also found downregulation of a goblet cell marker gene (Gp2) in the bleb conjunctiva. MMC treatment suppressed elastin (Eln) gene expression and enhanced keratinization-related gene expression (Krt1, Lor) in the bleb region. Our results suggest the importance of epithelial wound healing after filtration surgery, and this filtration surgery model will be a useful tool for further pathophysiological analysis.

Casting A Wide Net On Surgery: The Central Role of Neutrophil Extracellular Traps.

: Since their discovery, neutrophil extracellular traps (NETs) have been implicated in a broad array of functions, both beneficial and detrimental to the host. Indeed, NETs have roles in infection, sepsis, wound healing, thrombotic disease, and cancer propagation, all of which are directly implicated in the care of surgical patients. Here we provide an updated review on the role of NETs in the perioperative period with specific emphasis on perioperative infections, wound healing, vascular complications, cancer propagation, as well as discussing ongoing, and future therapeutic targets. Surgeons will benefit from understanding the latest discoveries in neutrophil biology and how these novel functions affect the care of surgical patients. Furthermore, novel anti-NET therapies are being developed which may have profound effects on the care of surgical patients.

Concentration standardization improves the capacity of drainage CRP and IL-6 to predict surgical site infections.

IMPACT STATEMENT: The ability to predict surgical site infections (SSIs) early would be advantageous. Previous studies have investigated the use of inflammatory factors in fluids drained from surgical sites to predict SSI, but the diagnostic efficacy of this method requires improvement. Baseline levels of inflammatory factors vary between individuals, but this variation tends to differ in patients with and without SSIs. Therefore, we standardized subsequently acquired concentrations of interleukin 6 and C-reactive protein in fluids drained from surgical sites by dividing them by the concentrations determined at day 1 to preclude the confounding effects of differences in baseline levels. The standardized concentrations had higher predictive efficacy than the absolute concentrations. Standardizing the data rendered SSI prediction more precise and practical in a diverse group of real patients. This translational study suggests that inflammatory factors in fluid drained from injury sites are promising tools for the prediction of SSI in the clinic.

The perioperative presepsin as an accurate diagnostic marker of postoperative infectious complications after esophagectomy: a prospective cohort study.

BACKGROUND: Presepsin is suggested to be an accurate sepsis diagnostic biomarker, playing an important role in distinguishing infection from no-infection status. However, to date, there is no study determining presepsin's role in diagnosing post-esophagectomy infectious complications. METHODS: Thirty patients who underwent esophagectomy for esophageal carcinoma were included in this prospective observational study. We investigated preoperative presepsin levels' changes and evaluated the relationship between infectious complications and presepsin levels. Moreover, we analyzed the classification and regression tree (CART) to determine presepsin's optimal cutoff values for discriminating infectious complications. RESULTS: For 10 patients with infectious complications, median presepsin levels were 168, 337, 303, 271, 314, 978, and 752 pg/ml, pre- and immediately post-surgery, and 1, 2, 3, 5, 7 days post-surgery, respectively. Presepsin levels were significantly higher in the infectious complication group exclusively from preoperation to POD 7 (p = 0.048). Furthermore, area under the curve's value of presepsin on POD 5 and 7 was higher than the other three biomarkers included for discriminating infectious complications (i.e., procalcitonin, leukocyte, and C-reacted protein). We set an optimal cutoff value for presepsin calculated by CART. Specifically, on POD 5, the cutoff was 888 pg/ml with a sensitivity of 60% and a specificity of 90%, and on POD 7, the cutoff was 668 pg/ml with a sensitivity of 60% and a specificity of 85%. CONCLUSIONS: Presepsin levels on POD 5 and 7 after esophagectomy are a valuable indicator of infectious complication's detection vs. leukocyte, C-reacted protein, and procalcitonin.

TLR2 and caspase-1 signaling are critical for bacterial containment but not clearance during craniotomy-associated biofilm infection.

BACKGROUND: A craniotomy is required to access the brain for tumor resection or epilepsy treatment, and despite precautionary measures, infectious complications occur at a frequency of 1-3%. Approximately half of craniotomy infections are caused by Staphylococcus aureus (S. aureus) that forms a biofilm on the bone flap, which is recalcitrant to antibiotics. Our prior work in a mouse model of S. aureus craniotomy infection revealed a critical role for myeloid differentiation factor 88 (MyD88) in bacterial containment and pro-inflammatory mediator production. Since numerous receptors utilize MyD88 as a signaling adaptor, the current study examined the importance of Toll-like receptor 2 (TLR2) and TLR9 based on their ability sense S. aureus ligands, namely lipoproteins and CpG DNA motifs, respectively. We also examined the role of caspase-1 based on its known association with TLR signaling to promote IL-1ß release. METHODS: A mouse model of craniotomy-associated biofilm infection was used to investigate the role of TLR2, TLR9, and caspase-1 in disease progression. Wild type (WT), TLR2 knockout (KO), TLR9 KO, and caspase-1 KO mice were examined at various intervals post-infection to quantify bacterial burden, leukocyte recruitment, and inflammatory mediator production in the galea, brain, and bone flap. In addition, the role of TLR2-dependent signaling during microglial/macrophage crosstalk with myeloid-derived suppressor cells (MDSCs) was examined. RESULTS: TLR2, but not TLR9, was important for preventing S. aureus outgrowth during craniotomy infection, as revealed by the elevated bacterial burden in the brain, galea, and bone flap of TLR2 KO mice concomitant with global reductions in pro-inflammatory mediator production compared to WT animals. Co-culture of MDSCs with microglia or macrophages, to model interactions in the brain vs. galea, respectively, also revealed a critical role for TLR2 in triggering pro-inflammatory mediator production. Similar to TLR2, caspase-1 KO animals also displayed increased S. aureus titers coincident with reduced pro-inflammatory mediator release, suggestive of pathway cooperativity. Treatment of caspase-1 KO mice with IL-1ß microparticles significantly reduced S. aureus burden in the brain and galea compared to empty microparticles, confirming the critical role of IL-1ß in limiting S. aureus outgrowth during craniotomy infection. CONCLUSIONS: These results demonstrate the existence of an initial anti-bacterial response that depends on both TLR2 and caspase-1 in controlling S. aureus growth; however, neither pathway is effective at clearing infection in the WT setting, since craniotomy infection persists when both molecules are present.

Bioinformatic Analysis of the Wound Peptidome Reveals Potential Biomarkers and Antimicrobial Peptides.

Wound infection is a common and serious medical condition with an unmet need for improved diagnostic tools. A peptidomic approach, aided by mass spectrometry and bioinformatics, could provide novel means of identifying new peptide biomarkers for wound healing and infection assessment. Wound fluid is suitable for peptidomic analysis since it is both intimately tied to the wound environment and is readily available. In this study we investigate the peptidomes of wound fluids derived from surgical drainages following mastectomy and from wound dressings following facial skin grafting. By applying sorting algorithms and open source third party software to peptidomic label free tandem mass spectrometry data we provide an unbiased general methodology for analyzing and differentiating between peptidomes. We show that the wound fluid peptidomes of patients are highly individualized. However, differences emerge when grouping the patients depending on wound type. Furthermore, the abundance of peptides originating from documented antimicrobial regions of hemoglobin in infected wounds may contribute to an antimicrobial wound environment, as determined by in silico analysis. We validate our findings by compiling literature on peptide biomarkers and peptides of physiological significance and cross checking the results against our dataset, demonstrating that well-documented peptides of immunological significance are abundant in infected wounds, and originate from certain distinct regions in proteins such as hemoglobin and fibrinogen. Ultimately, we have demonstrated the power using sorting algorithms and open source software to help yield insights and visualize peptidomic data.

Do Prophylactic Antibiotics Reach the Operative Site Adequately?: A Quantitative Analysis of Serum and Wound Concentrations of Systemic and Local Prophylactic Antibiotics in Spine Surgery.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: To analyze the serum and drain concentrations of antibiotics administered by two different routes and compare the results. SUMMARY OF BACKGROUND DATA: Systemic antibiotics are expected to reach the surgical site and maintain adequate concentrations of the drug to prevent infection. However, it is unknown whether systemically administered antibiotics reach and maintain such adequate concentrations at the surgical wound or not. METHODS: Forty patients undergoing elective spine surgery received intra-wound Vancomycin (1 GM) before the wound closure and single dose of intravenous Gentamycin (80MG) immediately after surgery. Blood and drain samples were collected postoperatively to estimate serum and drain concentrations of Gentamycin and Vancomycin. Drug Estimation Protocol: Drug concentrations were estimated by ADVIA Centaur CP immunoassay (direct chemiluminescence). Gentamycin and vancomycin in the test samples competes with their respective acridinium ester-labeled gentamicin and vancomycin derivatives for monoclonal mouse anti-gentamycin and anti-vancomycin antibodies which are covalently coupled to paramagnetic particles in the solid phase. RESULTS: Gentamycin attained peak serum levels at 6 hours following administration with an average value of 9.90 ±â€Š3.1 µg/mL which was decreased to 6.76 ±â€Š2.6 µg/mL at 12 hours and steadily declining thereafter. Even though, the drug concentrations in the drain collection from the wound also attained peak levels at 6 hours, the drug concentrations were lower (3.75 ±â€Š1.4 µg/mL) than that of serum concentrations and inadequately attained the recommended target peak of Gentamycin (4-12 µg/mL).Wound levels of local vancomycin were significantly higher at 6 hours (413.4 ±â€Š217.3 µg/mL) and well maintained even at 72 hours. Serum vancomycin levels were observed to be highest at 6 hours in negligible concentrations of 6.06 ±â€Š2.2 µg/mL. CONCLUSION: After prophylactic systemic administration of the antibiotics, the antibiotic drug concentrations in the wound are much lower than the serum concentrations at any given time. After local intra-wound application of antibiotics, the drug concentrations in the wound are well maintained even after 72 hours. LEVEL OF EVIDENCE: 3.

Enterococcus faecalis exploits the human fibrinolytic system to drive excess collagenolysis: implications in gut healing and identification of druggable targets.

Perforations, anastomotic leak, and subsequent intra-abdominal sepsis are among the most common and feared complications of invasive interventions in the colon and remaining intestinal tract. During physiological healing, tissue protease activity is finely orchestrated to maintain the strength and integrity of the submucosa collagen layer in the wound. We (Shogan, BD et al. Sci Trans Med 7: 286ra68, 2015.) have previously demonstrated in both mice and humans that the commensal microbe Enterococcus faecalis selectively colonizes wounded colonic tissues and disrupts the healing process by amplifying collagenolytic matrix-metalloprotease activity toward excessive degradation. Here, we demonstrate for the first time, to our knowledge, a novel collagenolytic virulence mechanism by which E. faecalis is able to bind and locally activate the human fibrinolytic protease plasminogen (PLG), a protein present in high concentrations in healing colonic tissue. E. faecalis-mediated PLG activation leads to supraphysiological collagen degradation; in this study, we demonstrate this concept both in vitro and in vivo. This pathoadaptive response can be mitigated with the PLG inhibitor tranexamic acid (TXA) in a fashion that prevents clinically significant complications in validated murine models of both E. faecalis- and Pseudomonas aeruginosa-mediated colonic perforation. TXA has a proven clinical safety record and is Food and Drug Administration approved for topical application in invasive procedures, albeit for the prevention of bleeding rather than infection. As such, the novel pharmacological effect described in this study may be translatable to clinical trials for the prevention of infectious complications in colonic healing.NEW & NOTEWORTHY This paper presents a novel mechanism for virulence in a commensal gut microbe that exploits the human fibrinolytic system and its principle protease, plasminogen. This mechanism is targetable by safe and effective nonantibiotic small molecules for the prevention of infectious complications in the healing gut.

Preoperative Vancomycin Administration for Surgical Site Prophylaxis: Plasma and Soft-Tissue Concentrations in Pediatric Neurosurgical and Orthopedic Patients.

BACKGROUND: Vancomycin is used for antibiotic prophylaxis in pediatric surgical patients without a complete understanding of plasma and soft-tissue pharmacokinetics. Guidelines recommend incision within 60 minutes after administration; however, tissue vancomycin concentrations at that early time may not be therapeutic. We conducted a study of plasma and skin concentrations in pediatric neurosurgical and orthopedic patients to characterize intraoperative vancomycin pharmacokinetics. METHODS: Patients (0.1-18.8 years of age) undergoing posterior spinal fusion (n = 30) or ventriculoperitoneal shunt placement (n = 30) received intravenous vancomycin 15 mg/kg (maximum 1000 mg) over 1 hour. Skin was biopsied at incision and skin closure. Blood samples were collected at incision, at 2 and 4 hours intraoperatively, and at closure. Population pharmacokinetic analysis was performed to characterize pharmacokinetic parameter estimates and to develop a model of intraoperative plasma and skin vancomycin concentrations versus time. RESULTS: Pharmacokinetic analysis included data from 59 subjects, 130 plasma samples, and 107 skin samples. A 2-compartment model, volume of the central (Vc) and volume of the peripheral compartment (V2), proved to have the best fit. Stepwise covariate selection yielded a significant relationship for body surface area on elimination clearance and body weight on V2. Skin vancomycin concentrations rose continuously during surgery. Modeling predicted that equilibration of skin and plasma vancomycin concentrations took ≥5 hours. CONCLUSIONS: Skin vancomycin concentrations immediately after a preoperative dose are relatively low compared with concentrations at the end of surgery. It may be advisable to extend the time between dose and incision if higher skin concentrations are desired at the start of surgery.

Retrospective study to evaluate the clinical significance of a second rise in C-reactive protein level following instrumented spinal fusion surgery.

BACKGROUND: This study aimed to identify the incidence and causes of a second rise in C-reactive protein (CRP) levels following spinal instrumentation surgery and to help determine how an abnormal CRP response should be interpreted and managed during postoperative care. METHODS: The medical records of 948 patients who underwent instrumented spine fusion surgery and met the inclusion criteria were retrospectively reviewed to assess the frequency and causes of a second rise (SR) of CRP. A SR of CRP was defined when the CRP level after postoperative day 7 increased by more than 0.5 mg/dl from that at the previous time-point. The diagnostic cut-off value of CRP elevation for detection of surgical site infection (SSI) was determined. Cut-off values were analyzed using receiver operating characteristic (ROC) curves. Bayes' theorem was used to determine blood test posterior probabilities for SSI-positive cases using cutoff values of re-evaluated CRP levels. RESULTS: SR of CRP occurred in 107 of the 948 patients. Of the patients with SR of CRP, 38 (35%) patients had developed SSI, 33 (31%) patients had causes other than SSI, and the remaining 36 patients had unidentified causes. Among the patients with SR, excluding those with causes other than SSI, the best diagnostic cut-off value of SR for detection of SSI was 3.04 mg/dl (area under the curve was 0.74). The posterior test probability was 84.4%. CONCLUSIONS: For patients with SR of CRP, who had no causes other than SSI, an SR value of 3.04 mg/dl correlated with a high probability of developing SSI.

Antimicrobial action of autologous platelet-rich plasma on MRSA-infected skin wounds in dogs.

Effective antimicrobial preparations, other than antibiotics, are important for the treatment of potentially fatal drug-resistant infections. Methicillin-resistant Staphylococcus aureus (MRSA) is one of the leading causes of hospital-acquired and post- operative infections. Fortunately, the antimicrobial properties of platelet-rich plasma (PRP) against various microorganisms enable its potential use as an alternative to conventional antibiotics. The present work was designed to evaluate the hypothesized antimicrobial activity of PRP against MRSA infected skin wounds. Six adult male dogs were divided equally into control and PRP groups. Unilateral circular full-thickness skin wounds were created then a MRSA suspension was injected locally. Treatment started at 1st week post infection with subcutaneous infiltration of autologous activated PRP every week in the PRP group and with topical application of clindamycin cream twice daily in the control group. PRP decreased wound size and significantly increased wound contractility and re-epithelization, as confirmed by histopathological and immunohistochemical findings. Also PRP treated group showed significant decrease in ROS and redox imbalance with over expression of the TNF-α and VEGFA genes that indicate angiogenesis and maximum antibacterial activity after three weeks. In conclusion, CaCl2-activated PRP exhibited antimicrobial activity against MRSA infection, which improved the infected wound healing re-epithelization and granulation tissue formation.

A Perioperative Small Dose of Dexamethasone Enhances Postoperative Recovery by Reducing Volume and Inflammatory Contents in Wound Drainage After Thyroid Surgery: A Double-Blinded, Randomized, Prospective Study.

BACKGROUND: The aims of this study were to assess the effect of perioperative dexamethasone on postoperative thyroid surgery recovery using measures of wound drainage volume and C-reactive protein (CRP) levels and leukocyte counts. MATERIALS AND METHODS: From January to September 2014, healthy patients, aged between 18 and 65 years, had elective thyroid surgery in the tertiary hospital. Eligible patients were randomized into either group D (dexamethasone 0.1 mg/kg IV) or group S (saline IV) after anesthesia induction. At the end of surgery, a drainage tube was placed at the thyroid bed with a negative pressure ball connected outside the wound. Drainage fluids were collected after thyroid surgery. The fluid volume and the levels of C-reactive protein and leukocyte counts inside were analyzed. All patients were followed up for 1 month. RESULTS: The median total drainage in group D (n = 103) was 43 ml (IQR: 21-83 ml), and 68 ml (IQR: 35-104 ml) in group S (n = 111), P = 0.002. More patients in group D were discharged on postoperative day 2 (74.8% vs. 54.1%, P = 0.002). The CRP levels and leukocyte counts were much less in group D than in group S (P = 0.002 and P < 0.001, respectively). Two patients (one in each group) had wound infections 1 week after surgery that healed one additional week later. CONCLUSIONS: One perioperative small dose of dexamethasone reduced wound drainage volume and inflammatory content after thyroid surgery, thereby possibly contributing to early recovery. The effects of dexamethasone have never been evaluated before under these conditions. REGISTRATION NUMBER: NCT02304250 ( http://www.clinicaltrials.gov ).

Impact of a preventive bundle to reduce surgical site infections in gynecologic oncology.

OBJECTIVE: To assess the impact of a surgical site infection (SSI) prevention bundle for Gynecologic Oncology patients at a large academic tertiary centre in Toronto, Canada. METHODS: A SSI prevention bundle was implemented in February 2017 including: preoperative chlorhexidine shower, prophylactic antibiotics, glycemic control, normothermia, and separate closing tray. Data were collected prospectively using the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) institutional data, and chart review of surgeries between January 2016 and September 2017 was performed. The primary outcome was rate of SSIs, secondary outcomes were: superficial, deep and organ space SSIs, sepsis, wound disruption, length of stay, 30-day readmission and reoperation. Logistic regression analysis was conducted to identify predictors of SSIs. RESULTS: 339 baseline and 224 post-intervention patients were included. 53 incurred one or more SSIs: 43 superficial, 6 deep, and 14 organ-space. The bundle decreased overall SSIs by 55% (12.1% to 5.4%, p = 0.008) and superficial SSIs by 54% (9.7% to 4.5%, p = 0.023). Improvement was sustained for 6 quarters. No significant difference was found in other secondary outcomes. On multivariable analysis, surgery in the pre-bundle period, BMI ≥30, laparotomies and longer operative duration were independent risk factors for overall SSIs (OR 2.23, 95% CI 1.06-5.06, -OR 3.01, 95% CI 1.57 - 5.87, OR 3.70, 95% CI 1.56 - 10.18 and - OR 2.16, 95% 1.11 - 4.19, respectively). CONCLUSIONS: This prevention bundle successfully decreased SSIs in patients undergoing gynecologic cancer surgery. We recommend improving quality of care by wide implementation of SSI prevention bundles in Gynecologic Oncology patients.

A mathematical model of the use of supplemental oxygen to combat surgical site infection.

Infections are a common complication of any surgery, often requiring a recovery period in hospital. Supplemental oxygen therapy administered during and immediately after surgery is thought to enhance the immune response to bacterial contamination. However, aerobic bacteria thrive in oxygen-rich environments, and so it is unclear whether oxygen has a net positive effect on recovery. Here, we develop a mathematical model of post-surgery infection to investigate the efficacy of supplemental oxygen therapy on surgical-site infections. A 4-species, coupled, set of non-linear partial differential equations that describes the space-time dependence of neutrophils, bacteria, chemoattractant and oxygen is developed and analysed to determine its underlying properties. Through numerical solutions, we quantify the efficacy of different supplemental oxygen regimes on the treatment of surgical site infections in wounds of different initial bacterial load. A sensitivity analysis is performed to investigate the robustness of the predictions to changes in the model parameters. The numerical results are in good agreement with analyses of the associated well-mixed model. Our model findings provide insight into how the nature of the contaminant and its initial density influence bacterial infection dynamics in the surgical wound.