Prosthetic Infection Research Articles

Synovial fluid white cell count and histopathological examination of periprosthetic tissue samples (frozen and permanent sections) in the diagnosis of prosthetic knee infection

Abstract The aim of the study was to determine prospectively the importance of synovial fluid white cell count and intraoperative frozen and permanent sections analysis (number of polymorphonuclear leukocytes per high-power field) in the diagnosis of septic total knee arthroplasty. There were studied prospectively 72 patients who needed a revision total knee arthroplasty between 2013-2015. 30 patients were diagnosed with prosthetic joint infection due to high rates of ESR (93%) and CRP (90%) and preoperative positive culture from aspirated synovial fluid and 42 patients were considered to have aseptic failure according to negative preoperative culture from joint aspirate. For all the patients was analysed synovial fluid white cell count and histopathological aspect of intraoperative frozen and permanent sections of periprosthetic tissue. The results showed a median value of 13800 of sinovial white cells count for infected knee and 92 for noninfected knee. 90% of the patients with joint infection had more than 5 polymorphonuclear leukocytes per high power field on intraoperative frozen sections and 83% on permanent sections. None of the patients from aseptic group had more than 5 polymorphonuclear leukocytes per field on permanent sections. The erythrocyte sedimentation rate and C-reactive protein level can be supplemented with cultures of aspirated joint fluid and fluid white cell count to confirm the diagnosis of periprosthetic infection. When the preoperative diagnosis remain unclear, the histological examination of frozen or permanent sections of periprosthetic tissue with at least 5 polymorphonuclear leukocytes per high power field, is predictive for the presence of infection.

Satisfaction of patients with Peyronie's disease after plaque surgery and bovine pericardium graft

IntroductionPlaque and bovine pericardium graft surgery is a useful tool for treating Peyronie's disease. ObjectiveTo determine patient satisfaction following this operation. Materials and methodsThis was a retrospective, observational and descriptive study. We collected data from the medical records of patients who underwent surgery between 2004 and 2015 and were evaluated through a postoperative satisfaction questionnaire. ResultsTwenty-eight operations were performed. Curve correction was achieved in 26 patients (95.3%). One patient (3.57%) required residual curve correction using Yachia's technique, and 1 patient (3.57%) had a severe complication consisting of prosthetic infection and urethrocutaneous fistulae. Twenty-one patients (75%) expressed satisfaction with the surgery. ConclusionsOur results show an acceptable level of satisfaction among our patients, with a low number of complications. However, further prospective, controlled and randomized studies are needed.

Preoperative Urine Culture Results Correlate Poorly With Bacteriology of Urologic Prosthetic Device Infections

IntroductionAlthough preoperative negative urine culture results and treatment of urinary tract infections are generally advised before artificial urinary sphincter (AUS) and penile prosthesis (PP) surgery to prevent device infection, limited evidence exists to support this practice. AimTo evaluate the relation between preoperative urine culture results and the bacteriology of prosthetic device infections. MethodsMen undergoing AUS and/or PP placement at a tertiary referral center from 2007 through 2015 were analyzed. A total of 713 devices were implanted in 681 patients (337 AUSs in 314 patients and 376 PPs in 367 patients), of whom 259 (36%) did not have preoperative urine culture and were excluded. The remaining 454 patients received standard broad-spectrum perioperative antibiotics. Two patient groups were identified based on preoperative urine cultures: group 1 had negative urine culture results and group 2 had untreated asymptomatic positive urine culture results identified postoperatively. Main Outcome MeasuresDevice infection was diagnosed clinically and cultures obtained from the explanted device and tissue spaces were compared with preoperative urine culture results. ResultsAlthough multivariate analysis showed that patients undergoing AUS placement had a 4.5-fold greater risk of positive urine culture results (114 of 250, 45%) compared with those undergoing PP placement (36 of 204, 18%; P < .001), infection rates between device types were similar (8 of 250 for AUSs [3%] and 7 of 204 for PPs [3%]; P = .89). At a median follow-up of 15 months, device infection occurred in 15 of 454 devices (3%) implanted and no differences in infection rates were noted between urine culture groups (10 of 337 in group 1 [3.3%] and 5 of 117 in group 2 [4.3%]; P = .28). Remarkably, only 1 of 15 device infections (7%) had the same organism present at preoperative urine culture. ConclusionsDespite the finding that patients with AUS placement had a 4.5 times higher rate of positive urine culture results than patients with PP placement, preoperative urine culture results appeared to show little correlation with the bacteriology of prosthetic device infections.

Cryopreserved Human Allografts for the Reconstruction of Aortic and Peripheral Prosthetic Graft Infection.

Background: This study aimed to present cases with cryopreserved human allografts (CHAs) for vascular reconstruction in both aortic and peripheral infected prosthetic grafts.Materials and Methods: This is a single center, observational descriptive study with retrospective analysis. In all cases, the infected prosthetic graft material was completely removed. At discharge, patients were administered anticoagulants. Follow-up examinations included clinical visits, echo-color-Doppler ultrasounds, or computed tomography angiography within 30 days and at 3, 6, and 12 months after the treatment, and then twice per year.Results: We treated 21 patients (90% men, n=19) with the mean age of 71±12 years and mean interval between the initial operation and replacement with CHA of 30 months [range, 1–216; interquartile range (IQR), 2–36]. In-hospital mortality was 14% (n=3); no CHA-related complication led to death. Limb salvage was 100%. No patient was lost at the median follow-up of 14 months (range, 2–61; IQR, 6–39). No rupture, aneurysmal degeneration, or re-infection occurred. Estimated freedom from CHA-related adverse events (95% confidence interval, 43–63) was 95% at 3 years.Conclusion: In our experience, CHAs are a viable option for prosthetic graft infections and provide satisfactory clinical results and favorable stability because of a very low rate of CHA-related adverse events during follow-up.

Globicatella sanguinis Osteomyelitis and Bacteremia: Review of an Emerging Human Pathogen with an Expanding Spectrum of Disease.

Background Globicatella sanguinis is an uncommon pathogen that may be misdiagnosed as viridans group streptococci. We review the literature of Globicatella and report 2 clinical cases in which catalase-negative Gram-positive cocci resembling viridans group streptococci with elevated minimum inhibitory concentrations (MICs) to ceftriaxone were inconsistently identified phenotypically, with further molecular characterization and ultimate identification of G sanguinis.MethodsTwo clinical strains (from 2 obese women; 1 with a prosthetic hip infection and the other with bacteremia) were analyzed with standard identification methods, followed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry, 16S recombinant ribonucleic acid (rRNA), and sodA polymerase chain reaction (PCR). The existing medical literature on Globicatella also was reviewed.ResultsStandard phenotypic methods failed to consistently identify the isolates. 16S PCR yielded sequences that confirmed Globicatella species. sodA sequencing provided species-level identification of G sanguinis. The review of literature reveals G sanguinis as an increasingly reported cause of infections of the urine, meninges, and blood. To our knowledge, this is the first reported case of an orthopedic infection caused by Globicatella sanguinis. A review of the 37 known cases of G sanguinis infection revealed that 83% of patients are female, and 89% are at the extremes of age (<5 or >65 years).Conclusions Globicatella sanguinis, an uncommon pathogen with elevated minimum inhibitory concentrations to third-generation cephalosporins, is difficult to identify by phenotypic methods and typically causes infections in females at the extremes of age. It may colonize skin or mucosal surfaces. Advanced molecular techniques utilizing 16S rRNA with sodA PCR accurately identify G sanguinis.

Editorial Comment: “Preoperative Urine Culture Results Correlate Poorly With Bacteriology of Urologic Prosthetic Device Infections”

Editorial Comment: “Preoperative Urine Culture Results Correlate Poorly With Bacteriology of Urologic Prosthetic Device Infections”

Missed diagnosis of acute stanford Type A aortic dissection presenting with abdominal pain in the setting of acute appendicitis

Acute Stanford Type A aortic dissection (ATAAD) has a high mortality rate, particularly with delayed diagnosis and treatment. A 30-year-old male Marfan patient presented to the emergency department with acute abdominal pain and underwent laparoscopic appendectomy for acute appendicitis about 15 h later. Postoperatively, the patient developed acute pulmonary edema and respiratory failure. Transthoracic echocardiogram revealed severe aortic insufficiency, 7.5 cm root aneurysm, severe left ventricular dysfunction, and probable ATAAD. Following computed tomography angiogram confirmation of ATAAD, he underwent emergency root and ascending aortic replacement with a composite mechanical valve graft 48 h after hospitalization. The patient had Escherichia coli pericarditis at time of sternotomy likely hematogenous from appendicitis and later also developed postoperative pneumonia. At 2 years follow-up, he was doing well without any evidence of prosthetic valve conduit infection. The simultaneous presentation of two unrelated pathologies with acute abdominal pain led to the initial missed diagnosis of ATAAD, which delayed treatment and increased risks for morbidity and mortality. Therefore, Marfan syndrome patients presenting with acute abdomen should be ruled out for acute aortic dissection despite any other obvious concomitant pathology, especially in younger patients.

A Case of Early Prosthetic Valve Endocarditis Caused by Staphylococcus warneri in a Patient Presenting With Congestive Heart Failure

Staphylococcus warneri, a coagulase negative staphylococcus, has been isolated in prosthetic device-related infections and has been reported as a rare cause of endocarditis. We report a case of prosthetic aortic valve S. warneri endocarditis, in which the patient lacked typical infectious signs and symptoms, instead presenting with congestive heart failure due to perforation of the valve. Providers should consider endocarditis with a low virulence pathogen such as S. warneri when a patient with a prosthetic valve presents with heart failure, even in the absence of fever, leukocytosis and other infectious symptoms.

Prosthetic Hip Loosening Due to Brucellar Infection: Case Report and Literature Review

Context:Brucellosis is actually considered to be the commonest zoonotic infection worldwide; conversely prosthetic infection due to brucella is extremely rare. Although diagnostic is easily achieved, management of such situations is extremely challenging.AimsTo report the case of prosthetic hip loosening due to brucellar infection, discuss management manners and to summarize data about 19 cases reported in the literature.MethodsWe report the case of a 73-year-old woman with brucellar prosthetic hip loosening treated with 2-stage exchange of the prosthesis and prolonged double antibiotherapyResultsAt two years follow up the patient is pain free with total functional recovery and no clinical and radiographic signs of prosthetic looseningConclusionsBrucella should be evocated as a cause of total joint arthroplasty infection especially in patients from endemic regions and with occupational exposure. Antibiotic treatment alone can be followed if there are no signs of implant loosening. Tow stage revision should be considered in other cases.

Textural features of 18F-fluorodeoxyglucose positron emission tomography scanning in diagnosing aortic prosthetic graft infection

BackgroundThe clinical problem in suspected aortoiliac graft infection (AGI) is to obtain proof of infection. Although 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography scanning (PET) has been suggested to play a pivotal role, an evidence-based interpretation is lacking. The objective of this retrospective study was to examine the feasibility and utility of 18F-FDG uptake heterogeneity characterized by textural features to diagnose AGI.MethodsThirty patients with a history of aortic graft reconstruction who underwent 18F-FDG PET/CT scanning were included. Sixteen patients were suspected to have an AGI (group I). AGI was considered proven only in the case of a positive bacterial culture. Positive cultures were found in 10 of the 16 patients (group Ia), and in the other six patients, cultures remained negative (group Ib). A control group was formed of 14 patients undergoing 18F-FDG PET for other reasons (group II). PET images were assessed using conventional maximal standardized uptake value (SUVmax), tissue-to-background ratio (TBR), and visual grading scale (VGS). Additionally, 64 different 18F-FDG PET based textural features were applied to characterize 18F-FDG uptake heterogeneity. To select candidate predictors, univariable logistic regression analysis was performed (α = 0.16). The accuracy was satisfactory in case of an AUC > 0.8.ResultsThe feature selection process yielded the textural features named variance (AUC = 0.88), high grey level zone emphasis (AUC = 0.87), small zone low grey level emphasis (AUC = 0.80), and small zone high grey level emphasis (AUC = 0.81) most optimal for distinguishing between groups I and II. SUVmax, TBR, and VGS were also able to distinguish between these groups with AUCs of 0.87, 0.78, and 0.90, respectively. The textural feature named short run high grey level emphasis was able to distinguish group Ia from Ib (AUC = 0.83), while for the same task the TBR and VGS were not found to be predictive. SUVmax was found predictive in distinguishing these groups, but showed an unsatisfactory accuracy (AUC = 0.75).ConclusionTextural analysis to characterize 18F-FDG uptake heterogeneity is feasible and shows promising results in diagnosing AGI, but requires additional external validation and refinement before it can be implemented in the clinical decision-making process.

Incidencia de infecciones protésicas primarias de cadera y rodilla en un centro de la Ciudad de México

BackgroundHip and knee prosthetic replacements have proven to be the most appropriate treatment in the joints that do not benefit from medical or arthroscopic interventions; however, infections are the most feared complication. It is recommended that the incidence of infection should not exceed 2%. Material and methodsThis was an observational, prospective, longitudinal and observational study conducted in patients fitted with a prosthetic joint from August 2011 to July 2012. Patients were followed up pre and post-surgery for one year to identify a prosthetic infection, diagnosed using international parameters. We calculated the incidence of prosthetic infection, as well as the incidence density. ResultsA total of 339 patients (179 hip and 160 knee) were included. Variations in the time of pre-operative antibiotics’ administration were observed. Six prosthetic infections were identified with an incidence rate of 1.79/339 arthroplasties, 2.2/179 hip procedures, and 1.25/160 knee arthroplasties. An incidence density of 0.02/year for hip arthroplasties and 0.11/year for knee procedures was identified. There were 4 infections of hip and 2 of knee. Five infections were acute and one chronic. The isolated microorganisms were E. faecalis, S. epidermidis (2), S. mitis, S. aureus and P. stomatis. ConclusionsThe incidence of prosthetic joint infection in the first year of follow-up at our centre is within the recommended parameters. Surgical techniques and organizational practices influence the results.

Prevention of Propionibacterium acnes biofilm formation in prosthetic infections in vitro

The role of Propionibacterium acnes in shoulder arthroplasty and broadly in orthopedic prosthetic infections has historically been underestimated, with biofilm formation identified as a key virulence factor attributed to invasive isolates. With an often indolent clinical course, P acnes infection can be difficult to detect and treat. This study investigates absorbable cements loaded with a broad-spectrum antibiotic combination as an effective preventive strategy to combat P acnes biofilms. P acnes biofilm formation on an unloaded synthetic calcium sulfate (CaSO4) bone void filler cement bead was evaluated by scanning electron microscopy over a period of 14 days. Beads loaded with tobramycin alone or vancomycin alone (as comparative controls) and beads loaded with a vancomycin-tobramycin dual treatment were assessed for their ability to eradicate planktonic P acnes, prevent biofilm formation, and eradicate preformed biofilms using a combination of viable-cell counts, confocal microscopy, and scanning electron microscopy. P acnes surface colonization and biofilm formation on unloaded CaSO4 beads was slow. Beads loaded with antibiotics were able to kill planktonic cultures of 106 colony-forming units/mL, prevent bacterial colonization, and significantly reduce biofilm formation over periods of weeks. Complete eradication of established biofilms was achieved with a contact time of 1 week. This study demonstrates that antibiotic-loaded CaSO4 beads may represent an effective antibacterial and antibiofilm strategy to combat prosthetic infections in which P acnes is involved.

Biofilm prevention of gram-negative bacterial pathogens involved in periprosthetic infection by antibiotic-loaded calcium sulfate beads in vitro

Biofilm formation represents a key stage in the pathogenesis of prosthetic infections (PIs). More tolerant to antibiotics than their planktonic counterparts, biofilm bacteria are difficult to eradicate using conventional therapeutic regimes. A common approach in PI management is the adjunctive use of localised antibiotics in addition to systemic administration in an attempt to protect the implant from colonisation by infiltrating bacteria. This study evaluates the antibacterial and antibiofilm efficacy of antibiotic-loaded dissolvable calcium sulphate, previously shown to be effective against key gram-positive pathogens, against gram-negative species important in the establishment of chronic infection in PIs.Synthetic calcium sulfate beads loaded with tobramycin, vancomycin and both antibiotics in combination were assessed for their ability to eradicate planktonic Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae strains. The efficacy of the beads in preventing biofilm formation and eliminating established biofilms over multiple days was evaluated using confocal laser scanning microscopy (CSLM) imaging combined with image analysis and viable cell counts.Beads loaded with antibiotics demonstrated effective eluting concentrations for up to 37 d depending on the bacterial strain. In the presence of repeated bacterial challenges, antibiotic-loaded beads prevented bacterial colonisation and significantly reduce biofilm formation for the duration of the assay (7 d). Complete eradication of established biofilms was more difficult with evidence of biofilm regrowth after 1 week of contact with antibiotic-loaded beads, despite data suggesting a complete kill was achieved at earlier timepoints of 24 h and 72 h in the case of K. pneumoniae and P. aeruginosa.This study provides further evidence that calcium sulfate beads loaded with vancomycin and tobramycin may be a useful adjunctive component to the successful management of PIs.

Early prosthetic aortic valve infection identified with the use of positron emission tomography in a patient with lead endocarditis

Background18-Fluorodeoxyglucose positron emission tomography/computerized tomography (FDG PET/CT) scanning has recently been proposed as a diagnostic tool for lead endocarditis (LE). ObjectiveFDG PET/CT might be also useful to localize associated septic emboli in patients with LE. Case presentationWe report an interesting case of a LE patient with a prosthetic aortic valve in whom a trans-esophageal echocardiogram did not show associated aortic endocarditis. FDG PET/CT revealed prosthetic aortic valve infection. A second TEE performed 2 weeks after identified aortic vegetation. A longer duration of antimicrobial therapy with serial follow-up echocardiography was initiated. There was also increased uptake in the sigmoid colon, corresponding to focal polyps resected during a colonoscopy. ConclusionFDG PET/CT scanning seems to be highly sensitive for prosthetic aortic valve endocarditis diagnosis. This promising diagnostic tool may be beneficial in LE patients, by identifying septic emboli and potential sites of pathogen entry.

Partial versus complete removal of the infected mesh after abdominal wall hernia repair

BackgroundTo compare the results with complete mesh removal (CMR) versus partial mesh removal (PMR) in the treatment of mesh infection after abdominal wall hernia repair (AWHR). MethodsRetrospective review of all patients who underwent surgery for mesh infection between January 2004 and May 2014 at a tertiary center. ResultsOf 3470 cases of AWHR, we reported 66 cases (1.9%) of mesh infection, and 48 repairs (72.7%) required mesh explantation. CMR was achieved on 38 occasions, while PMR was undertaken ten times. We observed more postoperative complications in CMR than PMR group (p = 0.04). Three patients with intestinal fistula were reoperated in postoperative period after a difficult mesh removal; one of them died due to multiple organ failure. The overall recurrence rate after explantation was 47.9%: recurrence was more frequent in CMR group (p = 0.001), although persistent or new mesh infection was observed more frequently with PMR (p = 0.001). ConclusionsAlthough PMR has less postoperative morbidity, shorter duration of hospitalization and lower rate of recurrence than CMR, prosthetic infection persists in up to 50% of cases.

Design and development of novel antibacterial Ti-Ni-Cu shape memory alloys for biomedical application.

In the case of medical implants, foreign materials are preferential sites for bacterial adhesion and microbial contamination, which can lead to the development of prosthetic infections. Commercially biomedical TiNi shape memory alloys are the most commonly used materials for permanent implants in contact with bone and dental, and the prevention of infections of TiNi biomedical shape memory alloys in clinical cases is therefore a crucial challenge for orthopaedic and dental surgeons. In the present study, copper has been chosen as the alloying element for design and development novel ternary biomedical Ti‒Ni‒Cu shape memory alloys with antibacterial properties. The effects of copper alloying element on the microstructure, mechanical properties, corrosion behaviors, cytocompatibility and antibacterial properties of biomedical Ti‒Ni‒Cu shape memory alloys have been systematically investigated. The results demonstrated that Ti‒Ni‒Cu alloys have good mechanical properties, and remain the excellent shape memory effects after adding copper alloying element. The corrosion behaviors of Ti‒Ni‒Cu alloys are better than the commercial biomedical Ti‒50.8Ni alloys. The Ti‒Ni‒Cu alloys exhibit excellent antibacterial properties while maintaining the good cytocompatibility, which would further guarantee the potential application of Ti‒Ni‒Cu alloys as future biomedical implants and devices without inducing bacterial infections.

Vascular Graft Infections, Mycotic Aneurysms, and Endovascular Infections: A Scientific Statement From the American Heart Association.

### Background The use of synthetic material for reconstructive vascular surgery was first reported during the early 1950s. Infection involving vascular graft prostheses is an infrequent but devastating complication of reconstructive vascular graft surgery and is associated with a high morbidity and, in some situations, mortality. Improvements in surgical techniques and graft design, including the use of native venous or arterial tissue, have reduced the frequency of infection and severity of complications from vascular graft infection (VGI). However, these advances have also led to more frequent vascular graft procedures occurring in a patient population with multiple underlying comorbidities that would have previously disqualified them as candidates for vascular reconstructive surgery. Underlying comorbidities, such as diabetes mellitus or immune compromise, increase the risk of infection and serious infection-related complications. The major complications of VGI include sepsis, amputation, disruption of infected anastomotic suture line with rupture or pseudoaneurysm formation, embolization of infected thrombi, reinfection of reconstructed vascular grafts, enteric fistulae to the small or large bowel, bacteremic spread of infection to other sites, and death. VGIs can be categorized broadly into those that occur in an extracavitary location, primarily in the groin or lower extremities, or in an intracavitary location, primarily within the abdomen or less commonly within the thorax. ### Frequency The frequency of VGI depends on the anatomic location of the graft. The infection rate is 1.5% to 2% for most extracavitary grafts and as high as 6% with vascular grafts in the groin.1–9 For intracavitary grafts, the infection rate is ≈1% to 5%.1–6 Graft infection is most common after emergency procedures and after reoperation.1–4,10 Aortic graft erosion or fistulous communication into the duodenum or other areas of the bowel reportedly occurs in 1% to 2% of patients after aortic reconstruction.11, …

Extracolonic Clostridium difficile Infection with Peri-rectal Abscesses: A Rare Occurence

Introduction:Clostridium difficile (C.difficile) is the agent implicated for pseudomembranous colitis. It is responsible for 10% - 25% of cases of antibiotic associated diarrhea. Extracolonic manifestations of clostridium difficile infections are rare and very few reports have been published in the literature. We present a case of recurrent clostridium difficile colitis in a patient with rectal adenocarcinoma treated surgically, presenting with multiple peri-rectal abscesses with polymicrobial clostridium difficile infection. Case: 74 y/o female with past medical history significant of rectal adenocarcinoma s/p neoadjuvant chemotherapy and surgery, hypertension, CVA, seizure disorder and recurrent C.difficile colitis presented to the hospital with intermittent diarrhea for 3 weeks. The diarrhea was associated with intermittent rectal bleeding for 10 days, right lower quadrant abdominal pain, nausea and vomiting. The patient was started on iv metronidazole and PO vancomycin. CT abdomen and pelvis revealed 1.9 x 4.8 x 1.9 cm fluid collection in the left peri-rectal fossa, 2.1 x 3.3 x 2.8 cm fluid collection in the right peri-rectal fossa with air and a 2.3 cm collection of air in the left pelvic wall muscle. MRI of the pelvis revealed heterogenous signal and contrast enhancement in the sacrum consistent with post treatment changes or fibrosis. IR guided bone biopsy was negative for osteomyelitis or metastasis. IR guided drainage of the perirectal abscesses was also performed with placement of a drain. The culture was positive for candida dubliniensis, streptococcus milleri and clostridium difficile. She was hence started on fluconazole, iv vancomycin for streptococcus milleri and oral vancomycin was switched to fidaxomicin along with iv metronidazole for treatment of C.difficile. Patient eventually had resolution of symptoms along with improvement in nutritional status. Discussion: Extracolonic manifestations of clostridium difficile infection include osteomyelitis, bacteremia, visceral abscesses, empyema, pyelonephritis, prosthetic infection, reactive arthritis, skin and soft tissue infections. It is more common in patients with significant comorbidities and relative immunosuppression. Studies have also shown that increased extracolonic infections are seen in patients with intestinal surgery as evident in our patient. Most of the cases are polymicrobial in nature and treatment has been directed towards all organisms as described in our case.Figure 1Figure 2

An Unusual Presentation of Native Valve Endocarditis Caused by Staphylococcus warneri

Staphylococcus warneri is a coagulase-negative staphylococcal (CoNS) bacterium. It is a common saprophyte on human skin, present in approximately 50% of the healthy adult population; it has emerged as a cause of serious infection in the past two decades. In most cases, there is a predisposing condition, such as a new implant or surgical procedure, before the identification of S warneri as the pathogen. It is believed that CoNS are mostly associated with prosthetic valve infections. S warneri can lead to a slow growing and an indolent course and late diagnosis. Cases of CoNS infective endocarditis are less likely to have a vascular or immunologic phenomenon and can lead to large vegetations requiring valve replacement if not detected in time. There are currently only two cases of native valve endocarditis from community-acquired S warneri in the literature. We report a case of native valve endocarditis in an immunocompetent patient without any of the usual predisposing risk factors. Our case illustrates the importance of CoNS bacteremia and the implications of delayed diagnosis of CoNS endocarditis in clinical practice.

Late Fate of Cryopreserved Arterial Allografts

Initial enthusiasm for use of cryopreserved arterial allografts was subsequently tempered by suboptimal long-term outcome. Thrombosis, anastomotic pseudo-aneurysm, allograft disruption, aneurysmal degeneration, recurrent intestinal fistulization, and persistent infection are commonly reported in series with long-term follow-up. The authors reviewed their experience over the past 15 years with the use of cryopreserved arterial allografts as a vascular substitute for vascular prosthetic infection or for primary arterial infection, to investigate allograft-related complications. A retrospective analysis of prospectively collected data was conducted for 103 cryopreserved arterial allografts inserted in 96 patients between July 2000 and July 2015. There were 78 patients with infected vascular prosthesis (IVP), nine patients with an aorto-enteric fistula (AEF), and nine patients with primary arterial infection (PAI). The in-hospital mortality was eight out of 78 (9%) IVP patients, three out of nine AEF patients, and zero out of nine PAI patients. Median follow-up was 49 months. Allograft-related re-interventions were necessary in 29% of the patients with IVP and four of the patients with AEF, but none of the patients with PAI. Five-year survival for the IVP, AEF, and PAI patients was 53%, 44%, and 90%, respectively. This series highlights some shortcomings of cryopreserved arterial allografts in the long term, including suboptimal outcome-results and shortage of material. The authors discuss the allograft-related complications and suggest some tricks to minimize their risk.