Sonication in the diagnosis of fracture-related infections (FRI)-a retrospective study on 230 retrieved implants.

BACKGROUND: In fracture-related infections (FRI), both the diagnosis of the infection and the identification of the causative pathogen are crucial to optimize treatment outcomes. Sonication has been successfully used for periprosthetic joint infections (PJI); however, its role in FRI remains unknown. Our aim was to determine the diagnostic accuracy (sensitivity, specificity) of sonicate fluid culture (SFC). The primary objective was to compare SFC with peri-implant tissue culture (PTC) overall and among subgroups using the consensus definition by Metsemakers et al. The secondary objective was to determine the yield of SFC in possible fracture-related infections (PFRI). METHODS: From March 2017 to May 2019, 230 cases of retrieved implants were retrospectively reviewed. To perform sonication, explants were placed in sterile polypropylene jars intraoperatively. After treatment in an ultrasonic bath (Bandelin, Berlin, Germany), sonicate fluid was incubated into blood culture bottles, and conventional culturing was eventually performed. Sensitivity and specificity were determined using two-by-two contingency tables. McNemar's test was used to compare proportions among paired samples while Fisher's exact test was used for comparison between categorical variables. RESULTS: Of the 230 cases, 107 were identified as FRI, whereas 123 were aseptic revision cases (ARC). Of the latter, 105 were labeled as PFRI. Sensitivity of SFC was higher in comparison with PTC, although this did not reach statistical significance (90.7% vs. 84.1%; p = .065). The specificity of SFC was significantly lower than that of PTC (73.2% vs. 88.6%; p = .003). In PFRI, SFC yielded significantly more positive results than PTC (33/105 vs. 14/105; p = .003). Overall, 142 pathogens were identified by SFC, whereas 131 pathogens were found by PTC. CONCLUSIONS: We found that sonication of fracture fixation devices may be a useful adjunct in FRI, especially in "low-grade" infections lacking confirmatory clinical criteria. Standardized diagnostic protocols are warranted in order to further optimize the diagnostic accuracy.

Fate of Hardware in Spinal Infections.

Background: Removal of hardware with irrigation and debridement in patients with surgical site infections (SSIs) is performed commonly. However, the removal of hardware from patients with SSIs after spinal procedures is controversial. Moreover, primary spinal infections such as spondylodiscitis may require instrumentation along with surgical debridement. The purpose of this article was to evaluate critically and summarize the available evidence related to retention of hardware in patients with deep SSIs, and the use of instrumentation in surgical treatment of primary spinal infections. Methods: A literature search utilizing PubMed database was performed. Studies reporting the management of deep SSIs after instrumented spinal procedures, and of primary spinal infections using instrumentation published in peer-reviewed journals were included. Identified publications were evaluated for relevance, and data were extracted from the studies deemed relevant. Results: Because SSIs occur typically during the early post-operative period before stable bony fusion has been achieved, the removal of instrumentation may be associated with instability of the spinal column, pseudarthrosis, progressive deformity, pain, loss of function, and deterioration in the activities of daily living (ADL). Hence, early SSIs after spinal instrumentation are usually treated without removal of hardware. Moreover, primary spinal infections such as spondylodiscitis may require surgical debridement and instrumentation in cases with associated instability. Conclusions: Retaining or using instrumentation in patients with SSIs after spinal procedures or in patients with primary spinal infections, respectively, are commonly practiced in the field of spine surgery. Further evidence is required for the development of definitive algorithms to guide spine surgeons in decision making regarding the fate of instrumentation in the treatment of spinal infections.

Salvage of rib stabilization hardware with antibiotic beads.

BACKGROUND: Surgical stabilization of rib fractures (SSRF) can be used to improve pulmonary mechanics; however, hardware infection is a morbid complication. Antibiotic impregnated beads have been used to suppress infection in orthopedic practices. We aimed to determine the efficacy of antibiotic beads for infected and at-risk SSRF hardware. METHODS: This is a single institution retrospective review of adults (18 years or older) that received SSRF between 2009 and 2017. Infected and at-risk hardware were managed with antibiotic beads. The primary outcome was bony union of rib fractures. RESULTS: There were 285 SSRF patients. Infection rate was 3.5%. Antibiotic beads were placed in 17 patients - 9 for infected hardware and 8 for prophylaxis. Increased body mass index (p = 0.04) and hemorrhagic shock at admission (p = 0.03) were risk factors for infection. There was 100% bony union post-operatively. CONCLUSION: SSRF hardware infection is morbid. Antibiotic beads can salvage SSRF hardware until bony union.

Lower risk of pelvic metalware infection with operative repair of concurrent bladder rupture.

BACKGROUND: Patients with traumatic bladder rupture frequently have associated pelvic fracture. With increasing numbers of pelvic fractures fixed internally, there are concerns that conservative management of bladder rupture may increase the risk of pelvic metalware infection. This study aims to determine if operative repair of bladder rupture in comparison to conservative management with catheter drainage alone is associated with a lower rate of infection of internal fixation device for concurrent pelvic fracture. METHODS: This is a retrospective cohort study of level IV evidence. From July 2001 through June 2013, 45 multi-trauma patients at a level 1 trauma centre were identified to have sustained bladder rupture with concurrent pelvic fracture requiring internal fixation. Clinicopathological data were extracted from the TraumaNET database, medical records and health-coding database. Patients were stratified into two retrospective cohorts, management with surgical repair and management with catheter drainage alone. Fischer's exact test was used to determine whether the rate of pelvic metalware infection was different in the two cohorts. RESULTS: Of the 45 patients, 13 had intraperitoneal bladder rupture, 28 had extraperitoneal bladder rupture and four had combined intra-extraperitoneal bladder rupture. The median age for this cohort was 31. Bladder rupture was surgically repaired in 36 patients and managed conservatively with catheter drainage in nine patients. The rate of pelvic internal fixation device infection was lower in patients managed with surgical repair compared with conservative management (5.6% versus 33.3%, P = 0.047). CONCLUSION: Operative repair of bladder rupture is associated with a lower rate of pelvic orthopaedic hardware infection in the presence of concurrent pelvic fracture requiring internal fixation.

Bacteriological aspects of chronic osteoarticular infections in adults: the influence of the osteosynthesis material.

BACKGROUND: The aim of this study is to establish the bacterial epidemiology of chronic osteoarticular infections in adults, to study the susceptibility of the isolated strains to antibiotics and to demonstrate the influence of osteosynthesis material thereon. PATIENTS AND METHODS: This is a retrospective study of 78 months, from January 2006 to June 2012, providing bacteriological samples from patients with osteitis and osteoarthritis in the Mohammed V military teaching hospital of Rabat. Isolation and identification of bacteria were made by bacteriological classical techniques. The antimicrobial susceptibility testing of the isolates was performed by disk diffusion agar method, as recommended by the Committee of the susceptibility of the French Society for Microbiology (CA-SFM). RESULTS: We collected 234 cases, 53% (n = 124) of patients without osteosynthesis material (group A) and 47% (n = 110) patients with osteosynthesis material (group B).We isolated 371 bacteria which 51.49 (n = 191) in group A and 48.51% (n = 180) in group B. Gram-positive cocci were the most frequent (n = 234), followed by the Gram-negative bacilli (n = 114) and the Gram-positive bacilli (n = 19). Our study shows that the rate of resistance to antibiotics in strains obtained from patients with osteosynthesis material is higher compared to those obtained from patients without osteosynthesis material. CONCLUSIONS: Chronic OA infection in adults is difficult to diagnose and treat. Its good management must be multidisciplinary.

A spinal infection with Staphylococcus pseudintermedius.

We present a case of a 60-year-old woman with an invasive spinal infection with Staphylococcus pseudintermedius associated with a 15-year-old spinal fixation device and epidemiological contact with dogs. It was confirmed on blood culture and culture from pus from the epidural abscess and successfully treated using similar treatment as for a Staphylococcus aureus infection - 6 weeks of intravenous flucloxacillin 2 g four times daily with a 6 week follow-on course of oral clindamycin 450 mg three times daily. This case represents the first reported deep abscess forming infection with this recently discovered organism. This case highlights that (1) S. pseudintermedius has a potential for invasive zoonotic infection, (2) treatment as for S. aureus appears adequate for resolution of the case, (3) the increased use of the matrix-assisted laser desorption/ionisation time-of-flight identification technique is leading to more specific identification of previously unrecognised organisms.

Staphylococcus lugdunensis: a neglected pathogen of infections involving fracture-fixation devices.

PURPOSE: Cases of fracture-fixation device infection involving Staphylococcus lugdunensis are not frequent. The clinical characteristics and the choice of treatment strategies of these infections are not obviously known to date. METHODS: We performed a review of fracture-fixation device infection involving S. lugdunensis managed by our centres. RESULTS: Among the 38 cases of fracture-fixation device infection involving S. lugdunensis, 53% were located in the tibia. Most of our cases (87%) were chronic infections. Purulent discharge, which occurred in 79% of cases, was the most frequent clinical symptom, followed by pain in 63%, local inflammation in 55%, and fever in 37%. Bacteremia and severe sepsis occurred in 10% and 18% of cases, respectively. Four cases (10%) were treated exclusively with antimicrobial treatment alone. Thirty-four cases (89%) were treated with a combination of surgery with antimicrobial therapy including surgical debridement, antibiotics and osteosynthesis device retention in six cases (16%), and osteosynthesis device removal in 27 cases (71%). The mean length of antibiotic treatment was 119 days. The relapse rate was high that was not related to selection of resistant strains. Polymicrobial infection had no impact on clinical outcome. A combination of surgery with antimicrobial therapy was identified as a significant prognostic factor associated with remission (p = 0.042). CONCLUSIONS: S. lugdunensis is probably involved in more infections than has been reported. Using appropriate microbiological methods laboratories should routinely identify the species of all coagulase-negative Staphylococci isolates involved in fracture-fixation device infection to better achieve the treatment strategies of fracture-fixation device infection involving S. lugdunensis.

The Effect of Negative Pressure Wound Therapy With Antiseptic Instillation on Biofilm Formation in a Porcine Model of Infected Spinal Instrumentation.

OBJECTIVE: This study evaluates the effect of negative pressure wound therapy with antiseptic instillation (NPWTi) in the clearance of infection and biofilm formation in an in vivo model of infected spinal implants compared to traditional treatment modalities. MATERIALS AND METHODS: Five pigs underwent titanium rod implantation of their spinous processes followed by injection of 1 x 106 CFUs/100µL of methicillin-resistant Staphylococcus aureus through the fascia at each site. At 1 week postoperatively, an experimental arm of 3 pigs received NPWTi, and a control arm of 2 pigs received wet-to-dry dressings. The persistence of local infection in the experimental group was compared to the control group using tissue cultures. Biofilm development on spinal implants was evaluated using scanning electron microscopy. RESULTS: Mean bacterial count showed a statistical difference between the experimental and the control groups (P < .05). Scanning electron microscopy revealed the presence of uniform biofilm formation across the surface of control group instrumentation, whereas the experimental group showed interrupted areas between biofilm formations. CONCLUSION: The authors concluded that NPWTi is associated with decreased bacterial load and biofilm formation compared to wet-to-dry dressings in an in vivo porcine model of infected spinal instrumentation.

Surgical Site Infections Caused by Methicillin-resistant Staphylococcus epidermidis After Spinal Instrumentation Surgery.

STUDY DESIGN: Retrospective case series. OBJECTIVE: To determine relevant demographics, clinical presentations, and outcomes of surgical site infections (SSIs) after spinal instrumentation (SI) surgery caused by methicillin-resistant Staphylococcus epidermidis (MRSE). SUMMARY OF BACKGROUND DATA: This is the first study looking specifically at MRSE-related SSIs after SI surgery. METHODS: We performed a retrospective review of patients with MRSE-related SSIs from 665 consecutive cases of SI surgery performed between 2007 and 2014 at our institution. RESULTS: During the study period, SSIs occurred in 21 patients. MRSE was isolated from cultures obtained from surgical wounds in nine of the 21 patients (43%). There were four males and five females with a mean age of 63.9 ±â€Š15.1 years. Six patients presented with inflammatory signs, such as wound drainage, pyrexia, erythema, and elevated C-reactive protein. Three patients did not have signs of infection, but had early implant failure, and were diagnosed by positive cultures collected at the time of revision surgery. The mean time from index surgery to the diagnosis of infection was 23.6 days (range, 7-88 days). In one patient, the implant was removed before antibiotic treatment was administered because of implant failure. Eight patients were managed with antibiotics and implant retention. During the follow-up period, MRSE-related SSIs in seven of the eight patients were resolved with implant retention and antibiotics without the need for further surgical intervention. One patient did not complete the antibiotic course because of side effects, and implant removal was required to control the infection. CONCLUSION: Early detection, surgical debridement, and administration of appropriate antibiotics for a suitable duration enabled infection control without the need for implant removal in the treatment of MRSE-related SSI after SI surgery. LEVEL OF EVIDENCE: 4.

Infected hardware after surgical stabilization of rib fractures: Outcomes and management experience.

BACKGROUND: Surgical stabilization of rib fracture (SSRF) is increasingly used for treatment of rib fractures. There are few data on the incidence, risk factors, outcomes, and optimal management strategy for hardware infection in these patients. We aimed to develop and propose a management algorithm to help others treat this potentially morbid complication. METHODS: We retrospectively searched a prospectively collected rib fracture database for the records of all patients who underwent SSRF from August 2009 through March 2014 at our institution. We then analyzed for the subsequent development of hardware infection among these patients. Standard descriptive analyses were performed. RESULTS: Among 122 patients who underwent SSRF, most (73%) were men; the mean (SD) age was 59.5 (16.4) years, and median (interquartile range [IQR]) Injury Severity Score was 17 (13-22). The median number of rib fractures was 7 (5-9) and 48% of the patients had flail chest. Mortality at 30 days was 0.8%. Five patients (4.1%) had a hardware infection on mean (SD) postoperative day 12.0 (6.6). Median Injury Severity Score (17 [range, 13-42]) and hospital length of stay (9 days [6-37 days]) in these patients were similar to the values for those without infection (17 days [range, 13-22 days] and 9 days [6-12 days], respectively). Patients with infection underwent a median (IQR) of 2 (range, 2-3) additional operations, which included wound debridement (n = 5), negative-pressure wound therapy (n = 3), and antibiotic beads (n = 4). Hardware was removed in 3 patients at 140, 190, and 192 days after index operation. Cultures grew only gram-positive organisms. No patients required reintervention after hardware removal, and all achieved bony union and were taking no narcotics or antibiotics at the latest follow-up. CONCLUSIONS: Although uncommon, hardware infection after SSRF carries considerable morbidity. With the use of an aggressive multimodal management strategy, however, bony union and favorable long-term outcomes can be achieved. LEVEL OF EVIDENCE: Therapeutic study, level V.

Retrospective study on the etiological spectrum and antibiotic resistance in infections associated with osteosynthesis materials.

AIM: To determine the prevalence of infections according to their etiologic spectrum and antibiotic sensitivity in patients with or without implants and endoprostheses. MATERIAL AND METHODS: This retrospective study was conducted based on a customized study protocol on 773 cases admitted to the Clinic of Orthopedics - Traumatology of the Iasi "Sf. Spiridon" Emergency Hospital in the interval January 1, 2003 - December 31, 2011 for postoperative infectious complication. RESULTS: S. aureus was more frequently found in the patients without implant (58.2%) and in those with subcutaneous implant (45.5%); the lowest frequency was noticed in the patients with endoprosthesis (27.1%), the frequency distributions showing marked statistically significant differences (p = 0.001). P. aeruginosa was more frequently detected in the patient group with endoprosthesis (30.2%), while in the other groups it was found in approximately 7% (p = 0.001). The presence of Acinetobacter spp. was significantly higher in patients with deep implant (12.9%), with the lowest frequency noticed in the patients without implant (4.5%) (p = 0.029). Of the total isolated and identified types, 59.6% were non-multidrug-resistant (non-MDR), the remaining 40.4% being MDR types. CONCLUSIONS: S. aureus was the most frequent etiological agent in patients with or without cutaneous implant (45.5 and 58.2%, respectively), and P. aeruginosa (30.2%) in the endoprosthesized patients. Implementation of a preoperative screening protocol for the identification of healthy S. aureus carriers (Methicillin-sensitive S. aureus - MSSA/Methicillin-resistant S. aureus - MRSA) and subsequent decolonization would be an efficient way of reducing the incidence of infections caused by this bacterium.

Remission rate of implant-related infections following revision surgery after fractures.

PURPOSE: In contrast to a large amount of epidemiological data regarding the incidence of implant infections after fracture management, surprisingly few have been published concerning the success of their treatment. METHODS: This was a single-centre cohort study at Geneva University Hospitals from 2000 to 2012 investigating the remission rates of orthopaedic implant infections after fracture repair and associated variables. RESULTS: A total of 139 episodes were included: There were 51 women (37%) and 28 immunosuppressed (20%) patients with a median age and American Society of Anaesthesiologists (ASA) score of 51 years and 2 points, respectively. The infected implants were plates (n = 75, 54 %), nails (24, 17%), wires (20), screws (10), cerclage cables or wires (3), hip screws (4) or material for spondylodesis (3). A pathogen was identified in 135 (97%) cases, including Staphylococcus aureus (73, 52%), coagulase-negative staphylococci (20), streptococci (7) and 19 Gram-negative rods. All patients underwent antibiotic treatment, and 128 (92%) remained in remission at a median follow-up time of 2.6 years (range one to 13 years). In multivariate logistic regression analysis, the plate infections were significantly associated with lower remission rates [65/75, 87%, odds ratio (OR) 0.1, 95% confidence interval (CI) 0.01-0.90]. No associations were found for gender, age, immune status, ASA score, additional surgical interventions (OR 0.4, 95% CI 0.1-4.1) or duration of antibiotic treatment (OR 1.0, 95% CI 0.98-1.01). CONCLUSIONS: Among all infected and removed orthopaedic implants, plates were associated with slightly lower remission rates, while the overall treatment success exceeded 90%. The duration of antibiotic therapy did not alter the outcome.

Implant contamination during spine surgery.

BACKGROUND CONTEXT: Postoperative spine infections have been reported to occur in 1% to 15% of patients and subsequently lead to significant morbidity and cost, with an elevated risk for instrumented cases. Every effort should be made to minimize the risk of intraoperative wound contamination. Consequently, certain practices are followed in the operating room to prevent contamination, many of which are not evidence based. Conversely, certain objects believed to be sterile are frequently overlooked as potential sources of contamination. PURPOSE: To assess to what degree contamination of spinal implants occurs during spine surgery and evaluate whether coverage of implants alters the rate of contamination. STUDY DESIGN: Prospective study. STUDY SAMPLE: This study included 105 consecutive noninfection surgical cases performed by a single spine surgeon that required the use of instrumentation. OUTCOME MEASURE: Spinal implant contamination. METHODS: Cases were randomized to have all implant trays either remain uncovered (n=54) or covered (n=51) with sterile surgical towels on opening until implants were required for the case. After the last implant was placed, a sterile culture swab was used to obtain a sample from all open implants that had been present at the start of the case. The paper outer wraps of the implant trays were sampled in each case as a positive control, and an additional 105 swabs were capped immediately after they were opened to obtain negative controls. Swab samples were assessed for bacterial growth on 5% sheep blood Columbia agar plates. Of note, only departmental funding was used and no applicable financial relationships exist with any author. RESULTS: No growth was observed on any of the 105 negative controls, whereas 99.1% of positive controls demonstrated obvious contamination. Cultures from implant samples demonstrated a 9.5% overall rate of contamination with 2.0% (n=1) of covered implants versus 16.7% (n=9) of uncovered implants demonstrating contamination. Length of time implant trays were open before sample collection; implant type (plate, rods, vs. polyetheretherketone), number of scrubbed personnel, and number of implants used were all not found to be significantly associated with implant contamination (p>.05). However, coverage of implants was found to significantly reduce the implant contamination rate (p=.016). CONCLUSIONS: The contamination of sterile implants during spine surgery was found to occur. However, this contamination was independent of the amount of time the implant trays remained open. Coverage of implants significantly reduces this contamination. Therefore, no matter the expected duration of a case, implant coverage is a simple modifiable way to reduce the risk of intraoperative wound contamination and potentially reduce postoperative infections.

Comparison of bulb syringe, pressurized pulsatile, and hydrosurgery debridement methods for removing bacteria from fracture implants.

Surgical-site infection is a common form of noscomial infection that can occur in fractures following internal fixation. Treatment of these infections has traditionally included preserving stable implants via debridement and antibiotic administration while the fracture is healing. Recent evidence indicated that this algorithm results in less-than-optimal rates of fracture union and infection eradication.The premise for this study is that bacterial removal from fracture implants using the Versajet Hydrosurgery System (Smith & Nephew, Memphis, Tennessee) method is better compared with the bulb syringe and pressurized pulsatile lavage methods. Thirty-two stainless steel, 4-hole, nonlocking, 3.5-mm fracture plates were incubated with Staphylococus aureus and divided into 4 groups. Eight plates in each group underwent irrigation with 1 L of saline using a bulb syringe lavage, pressurized pulsatile lavage, or the Versajet Hydrosurgery System method. Eight plates underwent no irrigation method and served as a control group. The residual bacterial loads following irrigation were quantitatively cultured. Each of the experimental groups had significantly reduced levels of bacteria adherent to the plate following irrigation compared with the control group (P=.0002). Furthermore, the Versajet Hydrosurgery System was most the effective at bacterial removal, followed by the pressurized pulsatile and bulb syringe lavage techniques (P=.0002 to P=.0012, respectively).Novel approaches to eradicate bacteria from implants, such as hydrosurgery technology, while maintaining rigid stability of healing fracture, may improve clinical outcomes.

Infectious pin complication rates in halo vest fixators using ceramic versus metallic pins.

STUDY DESIGN: Retrospective review of database patients. OBJECTIVE: To compare infectious pin complication rates utilizing ceramic pins, an emerging technology, with a large database of complications in halo's using metallic pins. SUMMARY OF BACKGROUND DATA: The halo/vest fixator remains a useful modality of treatment for cervical spine trauma but has been described as having a high incidence of complications, foremost pin-related complications. Ceramic pins and vest modifications have been introduced under the premise of (1) decreasing pin-tract infections compared with metallic pins manufactured from stainless steel or titanium and with the advent of 3T MRI, (2) decreasing brain MRI artifact, and (3) lowering MRI intolerance owing to material overheating. MATERIAL AND METHODS: We retrospectively reviewed a prospectively collected patient data set of the Harborview Medical Center spine trauma registry. A historic control group exclusively utilizing metallic halo pins over a 10-year period was compared with patients who were treated with halo's exclusively utilizing ceramic pins over a recent 14-month period. Complications investigated included aseptic, loosening, and infections graded on a novel 3-tier system adapted from external fixation in long bone and periarticular trauma. Inclusion criteria were the patients with traumatic cervical spine injuries treated with a halo for a period of at least 14 days. RESULTS: Forty-four patients were available for analysis in the ceramic pin group versus 263 in the metallic pin group. Overall pin complications amounted to 40.9% ceramic (C) versus 21.7% metal (M) pins (P<0.05), aseptic loosening rates 13.7% (C) compared with 8.3% (M), and pin site infections 27.3% (C) compared with 13.3% (M) (P<0.05). A grading system for halo pin tract infections was developed. In assessing overall complications and infections specifically, ceramic pins seemed to be associated with a higher incidence of adverse events or complications compared with titanium pins. CONCLUSION: Despite the imbalance of size of our cohort groups, there seems to be a strong trend toward the newer ceramic pin technology not meeting expected minimum performance standards set by the earlier metallic material. Causes for the higher failure rate likely lay in the necessary changes made to the halo vest and specifically the pin design owing to the inherent mechanical property limitations of MRI compatible materials.

Biofilm dispersal of community-associated methicillin-resistant Staphylococcus aureus on orthopedic implant material.

Orthopedic implant-related bacterial infections are associated with high morbidity that may lead to limb amputation and exert significant financial burden on the healthcare system. Staphylococcus aureus is a dominant cause of these infections, and increased incidence of community-associated methicillin-resistant S. aureus (CA-MRSA) is being reported. The ability of S. aureus to attach to the foreign body surface and develop a biofilm is an important determinant of resistance to antibiotic prophylaxis. To gain insight on CA-MRSA biofilm properties, USA300 biofilm maturation and dispersal was examined, and these biofilms were found to exhibit pronounced, quorum-sensing mediated dispersal from a glass surface. For comparison of biofilm maturation on different surface chemistries, USA300 biofilm growth was examined on glass, polycarbonate, and titanium, and minimal differences were apparent in thickness, total biomass, and substratum coverage. Importantly, USA300 biofilms grown on titanium possessed a functional dispersal mechanism, and the dispersed cells regained susceptibility to rifampicin and levofloxacin treatment. The titanium biofilms were also sensitive to proteinase K and DNaseI, suggesting the matrix is composed of proteinaceous material and extracellular DNA. These studies provide new insights on the properties of CA-MRSA biofilms on implant materials, and indicate that quorum-sensing dispersion could be an effective therapeutic strategy.