Prosthetic valvular endocarditis. A 12-year review

Prosthetic valve endocarditis - A trouble or a challenge?

Prosthetic valve endocarditis (PVE) represents a rare and serious complication of valve replacement associated with high morbidity and mortality, which significantly differs from native valve endocarditis (NVE). There are two major problems: establishing diagnosis and treatment of PVE. Diagnosis in PVE is challenging and often requires several imaging methods besides standard microbiological analyzes. Transesophageal echocardiographic examination remains the widely used imaging technique in PVE diagnosis, but additional techniques such as computed tomography (CT) and ¹⁸F-fluodeoxyglucose positron emission tomography/CT are often necessary. Persistent fever, embolic complications, valve dehiscence, intracardial abscess, heart failure, as well as staphylococcal and fungal PVE require surgical treatment to avoid lethal outcome. The introduction of transcatheter valve implantations and devices significantly complicated the approach - diagnostic and therapeutic to PVE patients. Despite constantly increasing knowledge regarding pathogenesis and treatment of PVE, the optimal therapy remains a matter of debate. Additional studies are necessary to define therapeutic strategies for this potentially fatal complication.

Mycotic Aneurysm of the Common Iliac Artery and Distal Aorta Following Stent Placement

A 43-year-old man was evaluated for disabling left leg claudication. Aortography demon strated occlusion of the left common and external iliac arteries with reconstitution of the left common femoral artery. During this procedure a 10 mm x 9.4 cm Wallstent was placed from the proximal common iliac to the mid-external iliac artery followed by a 10 mm Palmaz stent placed proximal to the Wallstent. He returned after 2 weeks with recurrent symptoms and an absent left femoral pulse. Repeat aortography confirmed that the stented iliac artery was thrombosed. Following thrombolysis, a stenosis distal to the Wallstent was identified and another 8 mm x 4 cm Wallstent was inserted to dilate the stenotic lesion. He did well until the following week when he returned complaining of fever, anorexia, and low back pain. Staphylococcus aureus was cultured from the blood. An initial computed tomography (CT) scan demonstrated only inflammation around the distal aorta, but owing to unremitting fever and symptoms, he underwent another CT scan 4 days later, which demonstrated a large aneurysm of the distal aorta and left common iliac artery. The patient was taken to the operating room where a right-to-left femorofemoral bypass was performed. After the groin wounds were closed, an exploratory laparotomy disclosed a large mycotic aneurysm of the distal aorta and proximal left common iliac artery. The aorta was oversewn below the level of the inferior mesenteric artery (IMA) and the Palmaz and proximal Wallstent were removed. An IMA thrombec tomy was performed because no Doppler flow was present in the sigmoid mesentery. Following abdominal closure, a right axillofemoral graft and thrombectomy of the femo rofemoral graft were performed. On postoperative day 12, he developed an ileus and signs of sepsis. Upon reexploration, a sigmoid perforation was discovered and a sigmoid resection and colostomy were performed. He was treated with parenteral antibiotics and enteral nutrition and was transferred for continued rehabilitation 8 weeks later.

Staphylococcus aureus infections: epidemiology, pathophysiology, clinical manifestations, and management

Staphylococcus aureus is a major human pathogen that causes a wide range of clinical infections. It is a leading cause of bacteremia and infective endocarditis as well as osteoarticular, skin and soft tissue, pleuropulmonary, and device-related infections. This review comprehensively covers the epidemiology, pathophysiology, clinical manifestations, and management of each of these clinical entities. The past 2 decades have witnessed two clear shifts in the epidemiology of S. aureus infections: first, a growing number of health care-associated infections, particularly seen in infective endocarditis and prosthetic device infections, and second, an epidemic of community-associated skin and soft tissue infections driven by strains with certain virulence factors and resistance to β-lactam antibiotics. In reviewing the literature to support management strategies for these clinical manifestations, we also highlight the paucity of high-quality evidence for many key clinical questions.

The changing face of prosthetic valve endocarditis at a tertiary-care hospital: 1986-2005

INTRODUCTION AND OBJECTIVES

To investigate changes in the clinical characteristics, etiology and prognosis of prosthetic valve endocarditis at a tertiary-care hospital.

METHODS

Retrospective cohort study of all patients diagnosed with prosthetic valve endocarditis using modified Duke criteria between 1986 and 2005. The analysis covered two time periods: January 1986 to December 1995 (P1) and January 1996 to December 2005 (P2).

RESULTS

In total, 133 episodes of endocarditis occurred in 122 patients. Of these, 73 (54.9%) were diagnosed in P1 and 60 (45.1%) in P2, with incidences of 2.19% and 2.18%, respectively. The patients' mean age (SD) was 52.6+/-16.6 years in P1 and 66.2+/-11.5 years in P2 (P=.0001). Clinical characteristics were similar in the two study periods. The increase in Enterococcus infection was remarkable (12.5% in P2 vs. 4.9% in P1; relative risk [RR]=2.5; 95% confidence interval [CI], 0.7-9.6), as was the decrease in viridans group Streptococcus infection (12.5% in P2 vs. 31.1% in P1; RR=0.4; 95% CI, 0.2-0.9). Some 90.4% of patients (63/73) underwent surgery in P1, while 68.3% (41/60) underwent surgery in P2. The difference was significant (RR=0.8; 95% CI, 0.6-0.9). The in-hospital mortality rate was 28.8% in P1 and 30% in P2 (RR=1; 95% CI, 0.6-1.7).

CONCLUSIONS

Changes in the epidemiology and microbiological etiology of prosthetic valve endocarditis were observed over the 20-year study period. Diagnostic and therapeutic approaches also changed, but mortality remained high.

Current approach to the treatment of penile implant infections

Modern penile implants, introduced to the market almost four decades ago, have provided a predictable and reliable treatment of erectile dysfunction (ED) despite the development of less-invasive therapies. Infection associated with the placement of these devices does occur, and with prophylactic measures and protocols the incidence has decreased fortunately. In the presence of an infection the implant and all foreign material should be removed. A salvage procedure, during which the wound is thoroughly washed with antiseptic solutions after device removal and placement of a new implant during the same procedure, has a high success rate and is becoming a popular approach. The alternative, device removal with return at a later date for placing a new implant, entails a more difficult corporal dilation, and the resulting erection is noticeably shorter. Patient and partner satisfaction with a penile implant is the highest among all of the treatments for ED.

Penile implant infections: prevention and treatment

Penile implants remain a mainstay in treating erectile dysfunction (ED). Despite competing therapies, the number of devices implanted has increased each year. Implant infection continues to be a problem, but recent advances in antibiotic-coated devices and copious use of antiseptic irrigation have reduced the incidence. When confronted with an implant infection, a salvage procedure has gained acceptance that involves immediate replacement of the infected implant after antiseptic washing of the implant cavities. This procedure minimizes shortening of the implant erection and facilitates placement of cylinders in corporal bodies. Among patients and health care providers, satisfaction with penile implant remains the highest for all ED treatments.

Guideline for Prevention of Surgical Site Infection, 1999. Centers for Disease Control and Prevention (CDC) Hospital Infection Control Practices Advisory Committee

EXECUTIVE SUMMARY The "Guideline for Prevention of Surgical Site Infection, 1999" presents the Centers for Disease Control and Prevention (CDC)'s recommendations for the prevention of surgical site infections (SSIs), formerly called surgical wound infections. This two-part guideline updates and replaces previous guidelines.1,2 Part I, "Surgical Site Infection: An Overview," describes the epidemiology, definitions, microbiology, pathogenesis, and surveillance of SSIs. Included is a detailed discussion of the pre-, intra-, and postoperative issues relevant to SSI genesis. Part II, "Recommendations for Prevention of Surgical Site Infection," represents the consensus of the Hospital Infection Control Practices Advisory Committee (HICPAC) regarding strategies for the prevention of SSIs.3 Whenever possible, the recommendations in Part II are based on data from well-designed scientific studies. However, there are a limited number of studies that clearly validate risk factors and prevention measures for SSI. By necessity, available studies have often been conducted in narrowly defined patient populations or for specific kinds of operations, making generalization of their findings to all specialties and types of operations potentially problematic. This is especially true regarding the implementation of SSI prevention measures. Finally, some of the infection control practices routinely used by surgical teams cannot be rigorously studied for ethical or logistical reasons (e.g., wearing vs not wearing gloves). Thus, some of the recommendations in Part II are based on a strong theoretical rationale and suggestive evidence in the absence of confirmatory scientific knowledge.It has been estimated that approximately 75% of all operations in the United States will be performed in "ambulatory," "same-day," or "outpatient" operating rooms by the turn of the century.4 In recommending various SSI prevention methods, this document makes no distinction between surgical care delivered in such settings and that provided in conventional inpatient operating rooms. This document is primarily intended for use by surgeons, operating room nurses, postoperative inpatient and clinic nurses, infection control professionals, anesthesiologists, healthcare epidemiologists, and other personnel directly responsible for the prevention of nosocomial infections. This document does not: Specifically address issues unique to burns, trauma, transplant procedures, or transmission of bloodborne pathogens from healthcare worker to patient, nor does it specifically address details of SSI prevention in pediatric surgical practice. It has been recently shown in a multicenter study of pediatric surgical patients that characteristics related to the operations are more important than those related to the physiologic status of the patients.5 In general, all SSI prevention measures effective in adult surgical care are indicated in pediatric surgical care. Specifically address procedures performed outside of the operating room (e.g., endoscopic procedures), nor does it provide guidance for infection prevention for invasive procedures such as cardiac catheterization or interventional radiology. Nonetheless, it is likely that many SSI prevention strategies also could be applied or adapted to reduce infectious complications associated with these procedures. Specifically recommend SSI prevention methods unique to minimally invasive operations (i.e., laparoscopic surgery). Available SSI surveillance data indicate that laparoscopic operations generally have a lower or comparable SSI risk when contrasted to open operations.6-11 SSI prevention measures applicable in open operations (e.g., open cholecystectomy) are indicated for their laparoscopic counterparts (e.g., laparoscopic cholecystectomy). Recommend specific antiseptic agents for patient preoperative skin preparations or for healthcare worker hand/forearm antisepsis. Hospitals should choose from products recommended for these activitie

Guideline for prevention of surgical site infection, 1999. Hospital Infection Control Practices Advisory Committee

The “Guideline for Prevention of Surgical Site Infection, 1999” presents the Centers for Disease Control and Prevention (CDC)'s recommendations for the prevention of surgical site infections (SSIs), formerly called surgical wound infections. This two-part guideline updates and replaces previous guidelines.

Part I, “Surgical Site Infection: An Overview,” describes the epidemiology, definitions, microbiology, pathogenesis, and surveillance of SSIs. Included is a detailed discussion of the pre-, intra-, and postoperative issues relevant to SSI genesis.

Penile prosthetic infection: management by delayed and immediate salvage techniques

OBJECTIVES

A retrospective review was performed to determine success rates using explantation plus delayed (3 days) versus immediate reimplantation in managing an infected penile prosthesis.

METHODS

During a 9-year period, 41 patients who presented with an infected penile prosthesis underwent a salvage procedure. Group A (n = 31) underwent a delayed salvage procedure and group B (n = 10) underwent an immediate salvage procedure.

RESULTS

Successful salvage occurred in 71% in group A (delayed) and 80% in group B (immediate). Follow-up ranged from 30 to 108 months in group A and 5 to 16 months in group B. Analysis showed no statistically significant difference between the two treatment groups (P = 0.58). Failed salvage procedures were managed with device explantation and later reimplantation at 4 to 6 months.

CONCLUSIONS

In proper patient selection, immediate salvage appears as successful as delayed salvage procedures. Significant savings of healthcare dollars can be realized by an immediate salvage procedure if success rates prevail with longer term follow-up.

A study of 47 bacteremic Staphylococcus aureus endocarditis cases: 23 with native valves treated surgically and 24 with prosthetic valves

A retrospective review of medical records from the Staphylococcus Laboratory, Copenhagen, 1982-1991, was carried out at the Department of Clinical Microbiology, Statens Serum Institut, 1994-1995, to investigate the clinical features and outcome of two subgroups of bacteremic Staphylococcus aureus endocarditis cases in non-drug addicts: patients with prosthetic valve endocarditis (PVE) and patients with native valve endocarditis treated surgically. Twenty-four cases of PVE were included. Six cases were early (within 60 days of valve implantation) and 18 were late. The overall in-hospital mortality was 42%. Surgical treatment resulted in a non-significantly lower mortality as compared with medical treatment alone (0% vs 50%, p = 0.19). Medical treatment of aortic and mitral valve endocarditis resulted in similar mortality rates (44% and 50%, respectively). Twenty-three cases of native valve infective endocarditis had the valve replaced surgically. The in-hospital mortality was 22%, which was significantly lower as compared with medical therapy (69%, p < 0.0001). The treatment changed significantly during the study period: 6 of 112 patients (5%) were treated surgically in the first half of the period (1982-1986) compared to 17 of 124 patients (14%) in the second half (1987-1991, p = 0.049). Severe congestive heart failure was the main indication for cardiac surgery in 21 patients. In conclusion, a shift towards a more aggressive surgical approach has taken place in the 10-year period. This development should be strengthened in the future as surgical intervention may improve survival in patients with infective endocarditis caused by S. aureus whether the infected valve is prosthetic or native.

Fungal prosthetic valve endocarditis in 16 patients. An 11-year experience in a tertiary care hospital

Fungal prosthetic valve endocarditis (PVE) is an infrequent but serious complication of valve replacement surgery. To examine its long-term outcome, we retrospectively studied 16 patients with 19 episodes of definite fungal PVE. The mean age was 51 years (range, 27-71 yr). Onset of fungal PVE ranged from 8 days to 3.4 years after valve replacement. Candida albicans was the most common (56%) pathogen isolated. A portal of entry was identified in only 25% of the patients; the presence of intravascular catheters (50%) and prior bacterial endocarditis (38%) were leading predisposing factors. Fever (83%) was the most consistent clinical finding. Potentially serious embolic events, particularly strokes (32%), were common at presentation. Transesophageal echocardiography (sensitivity = 100%) was more useful than transthoracic echocardiography (sensitivity = 60%) in detecting lesions due to fungal PVE. Combined valve replacement surgery and amphotericin B (mean total dose of 1.8 g) in 15 patients resulted in an 87% in-hospital survival and 67% overall survival with a mean follow-up of 4.5 years (range, 5 mo to 16 yr). Two patients had 3 late relapses of fungal PVE up to 9 years after the preceding episode. Each relapse was treated with repeat valve replacement and amphotericin B; in addition, oral azole was utilized for chronic suppression, although the efficacy of this strategy remains unproven. Because of the possibility of relapse, long-term follow-up is essential even after surgical and prolonged antifungal therapy.

The prosthesis salvage operation: immediate replacement of the infected penile prosthesis

PURPOSE

We describe our experience with salvage of the infected penile prosthesis at initial presentation in 11 patients.

MATERIALS AND METHODS

All patients with prosthesis infection who presented since 1991 were considered for salvage surgery. Contraindications to a salvage operation included necrotic infections, diabetic patients with purulence in the corporeal bodies, rapidly developing infections and erosion of the device cylinders.

RESULTS

In 1 patient in this group a salvage attempt was repeated after re-infection, for an overall success rate of 91%. Mean followup for the group was 21 months (range 9 to 42). Staphylococcus epidermidis was the infecting organism in 75% of our patients.

CONCLUSIONS

Our experience demonstrates the safety and advantages of the immediate salvage technique.

Prosthetic valve endocarditis in the ICU. Prognostic factors of overall survival in a series of 122 cases and consequences for treatment decision

We carried out univariate and multivariate analysis of outcome among 122 patients with prosthetic valve endocarditis (PVE) admitted to our ICU between 1978 and 1992. The predominant pathogens were Staphylococcus aureus (33%), streptococci (20%), coagulase-negative staphylococci (12%), enterococci (10%), and Gram-negative bacilli (9%). At 4 months, overall survival was 66% (42 deaths). Staphylococcus aureus was the main predictor of death (75% vs 15% with other pathogens). In S aureus PVE, multivariate analysis identified the following predictors of death: prothrombin time < 30% (relative risk [RR]: 8.3), concomitant mediastinitis (RR: 4.9), heart failure (RR: 4.4), and septic shock (RR: 2.6). In PVE due to other pathogens, prothrombin time < 30% (RR: 32.26), renal failure (RR: 7.31), and heart failure (RR: 6.07) were associated with death. In S aureus PVE, survival was higher in patients who received medical-surgical therapy than in those who received medical therapy alone (9/20 [45%] vs 0/20) (p < 0.01). In PVE due to other pathogens, there was no difference in survival between patients who underwent prosthesis replacement (89%) and those who received only medical treatment (81%). Among the 65 patients who underwent heart surgery, the mortality rate and incidence of postoperative paravalvular leakage did not correlate with positive prosthesis cultures. We conclude that non-S aureus and uncomplicated PVE may be managed without valve replacement but that prompt surgical intervention should be required in all other situations.

Diagnosing infection of extracardiac conduit in children

Between August 1985 and July 1992, at our center, 142 Japanese children had an extracardiac conduit operation to reconstruct the right ventricular outflow tract. The study group consisted of 22 of these 142 children who had a persistent fever and whose serum was positive for acute-phase reactants after the operation. We present the diagnostic findings for 10 children with infection of an extracardiac conduit that had been placed to restore the continuity of the right ventricle-pulmonary artery. They were part of the group of 22 children who were followed over the past 7 years with blood cultures, echocardiography, and 67Ga imaging. All 10 developed a persistent fever and were seropositive for acute-phase reactants. Conduit infection was diagnosed in only 2 patients by the detection of vegetation on echocardiography and was diagnosed in 9 of the 10 patients by an abnormal 67Ga uptake in the area of the artificial vessels used to reconstruct the pulmonary artery. The present study compared the use of blood cultures, echocardiography, and 67Ga imaging in diagnosing an infection of the extracardiac conduit. The sensitivity of blood cultures in diagnosing an extracardiac conduit infection was 70% (7/10), and the specificity was 92% (1/12). 67Ga imaging showed a higher sensitivity than echocardiography in diagnosing infection of an extracardiac conduit.

Intraatrial insertion of a mitral prosthesis in a destroyed or calcified mitral annulus

Infectious lesions and extreme calcification of the mitral valve annulus can make classic anatomic implantation of a prosthesis impossible. Confronted with these circumstances, we have developed a technique of intraatrial insertion of a mitral prosthesis. The prosthesis has been modified by enlarging the circumference of the sewing ring with a Dacron collar. The collar can be sutured to the left atrial wall above the mitral annulus. From 1981 to 1989, this technique has been employed in 36 patients: 15 had acute valve endocarditis with destruction of the mitral annulus and 21 had extensive annular calcification. In all cases, circumferential or partial intraatrial insertion permitted a secure implantation of the prosthesis. One operative death was related to the technique. It was an intractable bleeding caused by tearing of the very thin and fragile wall of the left atrium in a kidney transplant patient. Four patients were reoperated on for periprosthetic leak, in 3 of whom healing and cleaning of the mitral annulus permitted annular implantation of a prosthetic valve. There was no ventricular wall rupture. Our results suggest that the technique can be performed in high operative risk patients when mitral valve replacement is impossible by conventional techniques.

Rational approaches to the treatment of culture-negative infective endocarditis

The microorganism responsible for infective endocarditis may not be grown on blood culture in as many as 25% of cases. While this is to be expected with such relatively uncommon organisms as Coxiella burnetti, in most cases failure to grow the organism is likely to be due to either a low concentration of bacteria in the blood or because antibiotics were given before blood was taken for culture. The antibiotic treatment of culture-negative cases should be based on the assumption that the organisms responsible are the same as those found in cases with positive cultures, covering the most likely possibilities in such different circumstances as spontaneous infections of natural valves, endocarditis following cardiac surgery, early and late prosthetic valve endocarditis and infections associated with intravenous drug abuse.

Prosthetic valve endocarditis

Prosthetic valve endocarditis is an infrequent but serious complication of valve surgery. It occurred in 25 (3.2%) of 772 patients who received aortic, mitral or double valve replacement in 1971-1987. The total follow-up time was 3,976 patient years, giving an incidence of 0.63/100 patient years. Staphylococci were the most common of the cultured organisms in early and late infections-60% and 64%, respectively. The endocarditis was disclosed at autopsy in two cases. Treatment was antibiotics alone in 11 cases, and surgery was required in 12, the indication always being congestive heart failure. C-reactive protein level fell more rapidly than erythrocyte sedimentation rate in response to antibiotic or surgical management. The mortality rate was 73% in the antibiotic group and 33% in the surgical group. The findings demonstrated that an infected valve prosthesis should be replaced without delay if complications develop.

Sequential analysis of staphylococcal colonization of body surfaces of patients undergoing vascular surgery

Slime-producing coagulase-negative staphylococci are pathogens in vascular surgery by virtue of their ability to adhere to and persist on prosthetic graft material. Inguinal and abdominal skin sites were cultured in 41 patients upon hospitalization, and slime production and antimicrobial susceptibility were assessed in all recovered staphylococcal isolates. Twenty-one patients eventually underwent lower-extremity revascularization. In the operative population, cultures were also obtained on the day of surgery and fifth postoperative day. All 21 patients received perioperative cefazolin. Of 327 coagulase-negative staphylococci recovered, Staphylococcus epidermidis (47%), S. haemolyticus (21%), and S. hominis (10%) were the predominant isolates. Slime-producing coagulase-negative staphylococci were recovered from 17 of 21 patients at admission but only from 8 of 21 patients on day 5 postoperation (P less than 0.05). S. epidermidis isolates demonstrated increasing multiple resistance from admission to 5 days postoperation to methicillin, gentamicin, clindamycin, erythromycin, and trimethoprim-sulfamethoxazole (P less than 0.05). All coagulase-negative staphylococcal isolates were susceptible to ciprofloxacin and vancomycin. Slime-producing capability was not associated with increased methicillin resistance for the recovered isolates. The data demonstrate that patients enter the hospital colonized with slime-producing strains of coagulase-negative staphylococci and that during hospitalization the staphylococcal skin burden shifts from a predominately susceptible to a resistant microbial population, which may enhance the importance of slime production as a risk factor in lower-extremity revascularization.

Prognostic index in prediction of mortality from infective endocarditis

Out of 176 patients with infective endocarditis complicating rheumatic (120) and congenital heart disease (38), mortality occurred in 35 patients (19.9%). Presence of leukocytosis, heart failure, major embolisation and isolation of certain organisms including Staphylococci, beta-haemolytic Streptococci, Pseudomonas and Klebsiella were ominous with higher mortality rates compared with those when they were absent (P less than 0.02). Stepwise logistic multiple regression was then applied and the four most important independent variables were identified. A prognostic index for the prediction of mortality for infective endocarditis was then constructed by the summation of the regression coefficients. By applying this index, patients with infective endocarditis could be divided into subgroups with increasing proportional mortality from 5.8 to 83.3%. It provides an objective assessment of the risk patients with infective endocarditis, and a more reliable evaluation of benefit of any new treatment regimen, including cardiac surgery, during the acute stage.

Antibiotic prophylaxis in open-heart surgery: a comparison of cefamandole, cefuroxime, and cefazolin

We undertook a prospective randomized evaluation of cefamandole nafate, cefuroxime sodium, and cefazolin sodium as prophylaxis in open-heart operations. A total of 903 patients having an elective procedure were enrolled in the study, and 620 of them were eventually considered evaluable. There were no significant differences between the three study groups. The overall rate of infection and the rate of infection according to demographic variables was not significantly different between the three antibiotics. Serious complications and deaths were also similar between the three agents. The presence of multiple severe underlying conditions was a risk factor for infection, independent of the antibiotic used. We conclude that there are no differences in the efficacies of the three agents in preventing postoperative infections in patients having open-heart operation. Cefuroxime, principally because of its every-12-hour dose, is far less expensive than cefamandole or cefazolin.

Infectious complications of penile prosthesis surgery

Penile prosthetic surgery has become an increasingly common procedure. However, infection of the prosthesis remains a significant complication that almost always results in loss of the device. We present our 10-year experience with 9 infected prostheses among 417 total penile implants, for an over-all incidence of infectious complications of 2.2 per cent. A strict, broad-spectrum antibiotic schedule was adhered to rigidly by all patients, beginning preoperatively and continuing for a total of 10 days of perioperative coverage. Staphylococcus species were cultured in 56 per cent of the infected patients and in 100 per cent of the patients with positive cultures. Spinal cord injury patients showed a particular predisposition to prosthetic infection, with a 15 per cent incidence of infectious complications. Two other patients became infected after dental procedures and the need for routine antibiotic prophylaxis in the penile prosthesis patient is emphasized. Urinary tract instrumentation at the time of prosthetic implantation, whether planned or incidental, also appears to add a potentially avoidable risk for subsequent infection.

Effect of cardiopulmonary bypass on vancomycin and netilmicin disposition

The effect of cardiopulmonary bypass (CPB) on the disposition of vancomycin (15 mg/kg) and of netilmicin (3 mg/kg) was studied in 10 adults. The concentration-time profile of the drug in serum and renal clearance were characterized pre-CPB, during CPB, and post-CPB. Vancomycin and netilmicin exhibited initial decreases in mean concentrations in serum of 4.0 mg/liter (16.8%) and 2.2 mg/liter (29.1%), respectively, upon initiation of CPB. Netilmicin concentrations in serum rebounded to a mean of 0.6 mg/liter (15.4%) within 90 min on CPB and then continuously decreased. Vancomycin concentrations in serum demonstrated a rebound increase of 2.3 mg/liter (23.5%) at the end of CPB when the aorta was unclamped. Mean renal clearance throughout CPB was decreased for vancomycin (58.4 to 43.4 ml/min per m2) and netilmicin (53.4 to 31.5 ml/min per m2). The rebound in vancomycin concentration in serum strongly correlated with the length of time between unclamping the aorta and coming off CPB (r = 0.94), as well as with the increase in temperature upon rewarming (r = 0.92).

Gonococcal infections of penile prostheses

The first two known cases of Neisseria gonorrhoeae infection of a penile implant are reported. The literature regarding periprosthetic infections is reviewed, and the mode of transmission of the gonococcal organism to the corpora is discussed.

Staphylococcus epidermidis endocarditis and mitral valve prolapse

Staphylococcus epidermidis is an infrequent cause of native valve endocarditis. We describe two cases associated with mitral valve prolapse, and discuss the significance, diagnosis and management of this condition.

Influence of Staphylococcus aureus antibody on experimental endocarditis in rabbits

To evaluate the potential protective benefit of antibody to whole cells of Staphylococcal aureus for the prevention of endocarditis, the rabbit endocarditis model was used. Methicillin-sensitive (17A) and methicillin-resistant (173) S. aureus strains were evaluated in rabbits with or without indwelling intracardiac catheters. All immunized rabbits developed significant homologous agglutinating antibody titers (the mean reciprocal titers were 15,300 to strain 17A and 1,150 to strain 173). After challenge, virtually no significant differences were observed between immunized and unimmunized animals with respect to (i) incidence of endocarditis, (ii) concentration of bacteria in infected vegetations, (iii) incidence of metastatic renal abscesses, or (iv) concentrations of bacteria in infected kidneys. The clearance of homologous S. aureus strains from blood cultures was similar for immunized and unimmunized animals at 10 to 90 min after intravenous challenge. In vivo adherence of homologous S. aureus strains to aortic valves and vegetations was similar in immunized and unimmunized animals when evaluated at 30 and 90 min postchallenge. Even without catheterization, the incidence of bacteremia and renal abscesses was the same in immunized and unimmunized rabbits. Whole-cell-induced S. aureus antibody did not prevent or modify any stage in the development of endocarditis in rabbits.

[Bacterial endocarditis on prosthetic valves]

Bacterial endocarditis is a rare, but often lethal, complication of cardiac valve replacement. The endocarditis is called "early" when it occurs within 2 months of the operation, and "late" when it develops after that period. Contamination of the prosthesis with bacteria may occur intra-operatively or post-operatively. The clinical diagnosis is often difficult in early endocarditis when another focus of infection is present and in late endocarditis in the absence of fever and positive blood cultures. Isolation of the pathogen from blood cultures is essential to the diagnosis and treatment. Therapeutic surgery now has wider indications than formerly. The incidence of this dangerous complication can only be reduced by well-planned and well executed prophylactic measures.

Pseudomonas stutzeri causing late prosthetic valve endocarditis

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Prosthetic valve endocarditis. A survey

Fifty eight patients (aged 8-59 years, mean 27) treated for prosthetic valve endocarditis from January 1966 to January 1985 were studied retrospectively by review of case notes. There were 12 cases of early and 46 cases of late prosthetic valve endocarditis. These developed in 28 patients with an isolated aortic valve, in 26 with an isolated mitral valve, and in four with both aortic and mitral prosthetic valves. Streptococci were the most commonly isolated microorganisms, followed by staphylococci, Gram negative bacteria, and fungi. A surgical (34 cases) or a necropsy specimen (10 cases) from 44 cases was examined. Eighty two per cent of the patients had congestive heart failure. Twenty four of the 58 patients were medically treated and 17 died (70% mortality). Combined medical and surgical treatment was used in 34 patients; the main indication for surgery was congestive heart failure. Fourteen patients on combined treatment died (40% mortality). Persistent sepsis and prosthetic valve dehiscence were the most common early and late operative complications. The most important influences on outcome were congestive heart failure, the type of micro-organism, the severity and extent of anatomical lesions, the time of onset of prosthetic valve endocarditis, and the type of treatment. This survey indicates that only patients without congestive heart failure or embolic complications and with sensitive micro-organism should be treated medically. In view of the poor prognosis patients with prosthetic valve endocarditis associated with congestive heart failure, persistent sepsis, and repeat arterial emboli should be treated by early surgical intervention.

Fifty cases of late prosthetic valve endocarditis: improvement in prognosis over a 15 year period

The clinical course, prognostic factors, and management of 50 cases of late prosthetic valve endocarditis, occurring more than two months after valve replacement, were reviewed. Twenty nine cases that presented from 1971 to 1980 were compared with 21 cases that presented from 1981 to 1985. Apart from an appreciable decrease in the frequency of neurological complications between the first period (38%) and the second period (10%) no differences in clinical or bacteriological features were seen. Seventeen (59%) of the 29 cases in the earlier period and four (19%) of the 21 cases in the later period died. The rationale for antimicrobial treatment was similar during both periods. Cardiac surgery was performed in eight of 29 cases between 1971 and 1980 and in 11 of 21 between 1981 and 1985; the mean (SD) time between diagnosis of endocarditis and operation was 28 (19) days and 43 (44) days respectively. Six of the eight cases operated on in the first period died as did two of the 11 operated on in the second period. Twenty seven of the 29 cases presenting between 1971 and 1980 were treated with anticoagulants--either warfarin (15 of 27) or heparin sodium (12 of 27). Sixteen of the 21 cases presenting later were given anticoagulants and 15 of these cases were given heparin sodium. Control of anticoagulation was inadequate in nine of the 27 cases treated with anticoagulants during the first period and in only two of 16 treated during the second period. During the first treatment period neurological complications were more frequent when control of anticoagulation was inadequate.

Infectious complications of penile prosthetic implants

An infectious complication involving placement of a penile prosthesis is a disastrous event. A review of more than 300 devices placed between 1979 and 1984 at this center reveals an infectious complication rate of 8.3 per cent. Perioperative risk factors predisposing to infection included reoperation for technical failures, inadequate antibiotic coverage (specifically for Staphylococcus epidermidis), failure to perform a circumcision at the time of placement in uncircumcised patients and simultaneous placement with an artificial urinary sphincter device. No group of patients nor type of prosthesis was more susceptible to the development of a postoperative infection.

Prosthetic valve endocarditis caused by Acinetobacter calcoaceticus subsp. lwoffi

Acinetobacter spp. are uncommon etiologic agents of prosthetic valve endocarditis. Two patients with Acinetobacter calcoaceticus subsp. lwoffi prosthetic valve endocarditis are described. The patients were successfully treated with antibiotics (cefotaxime sodium and gentamicin sulfate); thus, we suggest medical treatment rather than early valve replacement in this particular type of infection.

A practical approach to prosthetic valve endocarditis

Prosthetic valve endocarditis (PVE) is an infrequent but dread complication, occurring in 1 to 2% of patients both early (less than 60 days) and late postoperatively. Diagnosis is always (99%) possible by two sets of blood cultures, but occasional exogenous causes of bacteremia may cloud the diagnosis, as will culture-negative cases of PVE and skin contaminants. With obvious exogenous sources of bacteremia, achieving sterile blood cultures after eradication of the noncardiac source permits discontinuation of antibiotics after two weeks. When skin contaminants are suspected, withholding antibiotics and obtaining two sets of blood cultures is recommended, because the bacteremia with PVE is continuous. Preventive measures, including perioperative antibiotics, are warranted but will probably not significantly reduce the low incidence of infection already achieved. The major cause of improved survival in recent years is earlier operation (valve rereplacement). This has been demonstrated in the last ten years and is absolutely indicated for major heart failure, ongoing sepsis, fungous etiology, valve obstruction, new-onset heart block, and unstable prosthesis by fluoroscopy.