Methicillin-resistant Staphylococcus aureus prosthetic aortic valve endocarditis with paravalvular abscess treated with daptomycin

Prosthetic valves have been used extensively for severe cardiac valvular dysfunction for the past 3 decades. Prosthetic cardiac valves may be infected with organisms causing bacteremia, particularly gram-positive cocci. Staphylococcus epidermidis (coagulase negative staphylococci) and Staphylococcus aureus , both methicillin-susceptible S. aureus and methicillin-resistant S. aureus (MRSA) strains, are the most frequent pathogens causing prosthetic valve endocarditis (PVE). Vancomycin has been the cornerstone of therapy for serious MRSA infections including bacteremia and endocarditis. Clinicians have noted that MRSA bacteremias treated with vancomycin often fail to clear even with prolonged therapy. Persistent or prolonged MRSA bacteremia unresponsive to vancomycin therapy has led to the treatment of these infections by other agents, that is, quinupristin, dalfopristin, linezolid, or daptomycin. These antibiotics have been found particularly useful in treating MRSA bacteremias unresponsive to vancomycin therapy. We report a case of a patient who presented with MRSA PVE complicated by perivalvular aortic abscess with persistent MRSA bacteremia unresponsive to vancomycin therapy. The patient's MRSA bacteremia was cleared with daptomycin therapy (6 mg/kg/d). Because the patient refused surgery, daptomycin therapy was continued in hopes of curing the endocarditis and sterilizing the perivalvular aortic abscess. Transesophageal echocardiogram revealed a decrease in abscess in the aortic perivalvular abscess after 1 week of daptomycin therapy. The patient made an uneventful recovery. The cure of PVE and perivalvular abscesses usually requires removal of the prosthetic device and abscess drainage. In this case, in which surgery was not an option, medical therapy of PVE and a decrease in size of the aortic perivalvular abscess were accomplished with daptomycin therapy. Daptomycin is an alternative to vancomycin therapy in patients with prolonged or persistent MRSA bacteremia secondary to endocarditis or abscess.     

Enterococcal endocarditis: a comparison of prosthetic and native valve disease

Between 1973 and 1987, 36 patients with 41 episodes of enterococcal endocarditis were seen at our institution. There were 22 episodes of native valve endocarditis (NVE) and 19 episodes of prosthetic valve endocarditis (PVE). The overall mortality before completion of therapy was 15% (18% due to NVE and 11% due to PVE). Among patients with NVE, involvement of the aortic valve was significantly associated with death or complicated illness (defined as the need for valve replacement before completion of antibiotic therapy or relapse of endocarditis after completion of therapy). Among patients who survived episodes of PVE, 69% were cured without surgical intervention. Gentamicin was administered in combination with a penicillin or vancomycin in the majority of episodes (mean duration of therapy with aminoglycosides: 5 weeks). Renal dysfunction occurred in 44% of patients who received gentamicin and occurred more frequently in patients with elevated serum creatinine levels before treatment. Our results suggest that enterococcal PVE can often be successfully treated with antibiotics alone, and they confirm the efficacy of gentamicin when it is administered in combination with cell wall-active agents for the treatment of endocarditis due to enterococci that lack high-level resistance to this agent.     

Serial echocardiographic appearance of healing bacterial vegetations.

Serial M mode and cross-sectional echocardiograms were obtained from six patients who had been treated with antibiotic drugs for infectious endocarditis. Three to six M mode echocardiograms and one to six cross-sectional echocardiograms were obtained from each patient over a follow-up period averaging 50 weeks (range 10 to 108 weeks). On echocardiography, vegetations were observed to have become smaller and more echo-reflective with healing. A dramatic change was seen in two patients after peripheral embolization. M mode echocardiography was particularly helpful in determining the quality of echo reflection by vegetations; cross-sectional echocardiography was more helpful in judging the size and shape of a vegetation. Echocardiography is ideally suited for the serial visualization of healing vegetations in patients who do not require early valve replacement. It may prove helpful to examine serially valve vegetations with both M mode and cross-sectional echocardiography when following up patients with infectious endocarditis treated with antibiotic agents.     

Prosthetic valve endocarditis

Fifty-three (3.6%; actuarially 4.1% at 48 months) of 1465 consecutive in-hospital survivors of valve replacement from 1975 to July 1979 (aortic, mitral, or aortic and mitral, only one untraced) developed prosthetic valve endocarditis (PVE). Incremental risk factors for developing PVE were native valve endocarditis (p less than .0001), black race (p = .0001), mechanical prosthesis (vs bioprosthesis) (p = .005), male sex (p = .04), and longer cardiopulmonary bypass time (p = .09). In general, the hazard function for developing PVE was greatest at 3 weeks after valve replacement. Patients with native valve endocarditis had a tendency to develop PVE early after valve replacement, as did patients in whom mechanical prostheses were used. PVE associated with Staphylococcus epidermidis tended to appear within 6 months of valve replacement, whereas streptococcal PVE tended to appear later after valve replacement. PVE took an atypical form in some patients, but patients with possible PVE (n = 6) had the same findings as those with certain PVE (n = 47). In 11 patients bacteriologic confirmation of PVE was not obtained. The typical prosthetic and periprosthetic characteristics of PVE were present in 30 of the 40 cases in which observations were possible. PVE is a serious condition; 34 (64%) of our 53 patients died. Most deaths occurred within 3 months of the first evidence of PVE. Recovery of some patients is possible with appropriate medical and surgical treatment, but more intense preventive measures are indicated.     

Association of teichoic acid antibody with metastatic sequelae of catheter-associated Staphylococcus aureus bacteremia: a failure of the two-week antibiotic treatment.

A patient with Staphylococcus aureus bacteremia associated with an infected intravenous catheter was treated with oxacillin for two weeks. During that period all blood cultures were sterile, he rapidly became afebrile, and there were no signs of endocarditis or metastatic abscesses. However, serum antibodies against staphylococcal teichoic acid, initially undetectable by the agar gel immunodiffusion technic, became positive during the second week of treatment. Three weeks after discharge, the patient was readmitted to the hospital because of back pain and weakness in the lower extremities. Vertebral osteomyelitis and a spinal epidural abscess caused by Staph. aureus of the same phage type as the bacteremic isolate were demonstrated. This case illustrates the importance of careful follow-up of patients with Staph. aureus bacteremia and the potential value of serial measurement of teichoic acid antibodies in detecting clinically inapparent complications of infection.     

Staphylococcal endocarditis on a heart valve prosthesis. Apropos of 28 cases

The purpose of this retrospective study of 28 cases of staphylococcal endocarditis on cardiac valve prosthesis was to evaluate the prognosis of that disease and the possible causes of its recent improvement. Between March 1977 and May 1987, 69 patients were treated for bacterial endocarditis on cardiac valve prosthesis. Among these, 28 patients (19 men, 9 women, mean age 53.2 +/- 14.3 years) had staphylococcal endocarditis (Staph. epidermidis in 18 cases, Staph. aureus in 10 cases) of early (10 cases) or late (18 cases) onset. Complications were present in no less than 27 out of 28 patients, the most frequent being heart failure, embolism or neurological disorders. The mortality rate was high (61 p. 100). Among the clinical variables studied, only a state of shock seemed to be predictive of death. Mortality was higher in the group treated medically (100 p. 100) than in the group treated surgically (50 p. 100). Since 1984, however, a significant decrease of mortality was noted; it coincided with the systematic use of vancomycin but also with surgical treatment in all cases. As a result of this study, we suggest that all patients with staphylococcal endocarditis on cardiac valve prosthesis should be operated upon and that this should be done as soon as possible, before the end of the classical antibiotic therapy period.     

Endocarditis due to strain of Cardiobacterium hominis resistant to erythromycin and vancomycin.

Endocarditis caused by Cardiobacterium hominis was observed in a penicillin-allergic patient with a prosthetic cardiac valve who had received prophylactic therapy with erythromycin for dental extractions. The organism was resistant to erythromycin and vancomycin, with minimal inhibitory concentrations of 12.5 microgram/ml and 25 microgram/ml, respectively, but was sensitive to penicillin G, tetracycline, cephalexin, and cefaclor. This case suggests that currently recommended antibiotic prophylactic therapy for endocarditis, especially in penicillin-allergic patients, may be inadequate for unusual pathogens such as C hominis.     

Conservative mitral valve surgery in the treatment of mitral regurgitation due to infective endocarditis. Report of 21 cases

BACKGROUND: To evaluate the feasibility of mitral valve repair in patients with infective endocarditis (IE). METHODS AND RESULTS: Forty-seven patients operated for mitral endocarditis between 1995 and 2005; 21 underwent mitral valve repair. The repair was performed for acute endocarditis in seven patients at a median of 14 days after the onset of treatment and 14 patients for healed endocarditis after a median of six months. RESULTS: Mitral valve repair was feasible in 21 patients (45%). This repair involved mitral annuloplasty in 16 patients (76%), shortening or transposition of chordae in 10 patients (48%), a pericardial patch in five patients (24%), and suture of perforation in two patients (9%). Associated procedures were aortic valve replacement in seven patients and tricuspid annuloplasty in two. There were no operative deaths. The mean follow up was five years (one to 11). One patient was reoperated for severe mitral regurgitation and another had a stroke due to cerebrovascular embolism in the first postoperative years. No recurrence of infectious endocarditis occurred. CONCLUSIONS: Mitral valve repair in IE gives satisfactory results in terms of survival and symptomatic improvement with a low operative risk. With antibiotic therapy, it provides a cure of mitral lesions even when carried out in the acute phase of endocarditis. Finally, it feasible in several cases with excellent results.     

Pneumococcal endocarditis: report of a series and review of the literature

Pneumococcal endocarditis has declined sharply in incidence since the advent of penicillin but remains a potentially lethal infection. From 1980 to 1984, pneumococcal endocarditis was diagnosed in seven patients--four adults and three infants. Apart from one patient who had had a splenectomy, there were no recognizable predisposing factors to infection due to Streptococcus pneumoniae, although all three children were younger than 15 months of age. Congenital heart disease was present in two patients, calcific aortic disease in one, and mitral valve prolapse in a fourth. The remaining three patients had previously normal hearts. Meningitis occurred in five (71%) of the seven patients. Five patients were cured of their infection: four by medical therapy alone (penicillin or vancomycin), and a fifth, by medical therapy plus valvular debridement. Two patients died: one with intractable heart failure, and the second, from the complications of cardiac surgery. Penicillin alone is effective therapy for pneumococcal endocarditis. Patients unable to tolerate penicillin may be treated with vancomycin.     

Hemophilus aphrophilus endocarditis: Review of 23 cases

A case of bacterial endocarditis caused by Hemophilus aphrophilus is described, and 22 previously reported cases are reviewed. Eleven patients died and 12 survived; comparison of these two groups reveals that the patients who died were in the older population. The male/female ratio was 3.6:1. The organism was difficult to identify but had a wide range of in vitro bacteriologic sensitivities. This type of endocarditis is frequently associated with emboli and congestive heart failure; each occurred in 9 of 11 fatal cases and 3 of 12 nonfatal cases. Among the nonfatal cases, two patients had both emboli and congestive heart failure, requiring aortic valve replacement despite their precarious clinical condition. Initial drug therapy before results of antibiotic sensitivity tests are known should consist of penicillin combined with streptomycin. When emboli or congestive heart failure appears in Hemophilus aphrophilus endocarditis, early surgical intervention with valve replacement is indicated.     

Short-term intramuscular therapy with procaine penicillin plus streptomycin for infective endocarditis due to viridans streptococci

Thirty-three patients with viridans streptococcal infective endocarditis were treated for two weeks with intramuscular procaine pencillin, 1.2 million units every 6 hours, plus streptomycin, 500 mg intramuscularly every 12 hours. Nine patients (27%) had infections with relatively penicillin-resistant microorganisms (MIC greater than 0.1 microgram/ml or MBC greater than or equal 3.12 microgram/ml). Follow-up ranged from 2 months to 3.5 years. There were no relapses; Mild vestibular toxicity developed in one patient. One patient died two months after completion of antimicrobial therapy from sudden onset of severe congestive heart failure; Seven patients required cardiac valve replacement after completion of antimicrobial therapy. None died. We believe that this therapeutic regimen is effective antimicrobial therapy for infective endocarditis caused by viridans streptococci, irrespective of in vitro microbiologic data.     

Infective endocarditis: diagnosis, treatment, and mortality, as related to surgical timing and infectious organism

To evaluate the timing of surgical treatment in infective endocarditis and to determine the relationship between the risk of mortality and the species of infectious organism, we reviewed a consecutive series of 65 cases involving patients with infective endocarditis who had been treated over a 17-year period. The patients included 41 males and 24 females, who ranged in age from 6 to 85 years (mean, 39.3 years). Forty-five had native valve endocarditis, 14 had prosthetic valve endocarditis, and six had endocarditis associated with congenital heart defects. Fifty-two patients underwent valve replacement, which was associated with an overall operative mortality of 19%. Those who underwent valve replacement during the early active stage (first 3 weeks) of infection had a higher mortality rate than those who had surgery either during the late active stage (second 3 weeks) of infection or after 6 weeks of antibiotic therapy. S. aureus and Pseudomonas organisms were responsible for the most deaths. On the basis of this study, we recommend that, when cardiovascular function permits, patients who are hemodynamically stable and free of emboli should receive 4 to 6 weeks of antibiotic therapy before undergoing surgical treatment. In contrast, patients with high-risk organisms are more likely to survive if subjected to early surgical intervention.     

Clindamycin therapy of Staphylococcus aureus endocarditis. Clinical relapse and development of resistance to clindamycin, lincomycin and erythromycin.

A 42 year old heroin addict with Staphylococcus aureus endocarditis of the mitral valve was treated with clindamycin phosphate, 600 mg intramuscularly, every 6 hours. The initial clinical response was excellent and blood cultures became negative. On the 26th day of clindamycin therapy, fever developed and six blood cultures taken during a 72 hour period grew Staph. aureus. The patient was subsequently cured with a six week course of nafcillin plus gentamicin followed by cloxacillin. The Staph. aureus isolated before clindamycin therapy and during relapse phage-typed 29/52/52A/79/80 and was resistant to penicillin G. The susceptibility of both Staph. aureus isolates to 19 antibiotics was unchanged. However, the Stahph. aureus developed marked resistance to clindamycin, lincomycin and erythromycin, to which the original isolate was susceptible. The resistance to clindamycin and lincomycin was heterogeneous whereas the entire cell population became homogeneously highly resistant to erythromycin. These antibiotics were not inactivated in vitro by the rapidly growing resistant Staph. aureus. The most likely site of resistance was at the 50 S subunit of the bacterial ribosome.     

Prosthetic valve endocarditis caused by Acinetobacter lwoffi: a case report and review

We are reporting a case of recurrent prosthetic-valve endocarditis (PVE) caused by an unusual pathogen. The patient suffered 2 consecutive relapses of Acinetobacter lwoffi bacteremia, although he had completed a full course of treatment with antibiotics to which the microorganism was susceptible. He was finally successfully operated with replacement of the infected aortic valve. Acinetobacter spp are relatively low-grade but potentially virulent pathogens, and endocarditis caused by these species can be fulminant, accompanied by septic complications, and fatal. Although some patients with relapsed PVE may respond to a second course of antibiotics and medical treatment rather than early valve replacement is suggested in A lwoffi PVE, combined antibiotic treatment and early surgical intervention may be considered as the first option in these patients.There are only a few cases of Acinetobacter endocarditis in the literature, and it is the first case reported in Greece to our knowledge.     

Recurrent endocarditis in silver-coated heart valve prosthesis

BACKGROUND AND AIM OF THE STUDY: In order to prevent prosthetic valve endocarditis (PVE), the implantation of a new silver-coated sewing ring has been introduced to provide peri- and postoperative protection against microbial infection. METHODS: A 56-year-old woman with aortic stenosis had elective replacement with a St. Jude Medical mechanical valve fitted with a silver-coated sewing ring (Silzone). The patient developed early PVE, which necessitated reoperation after one month. Despite a second Silzone prosthesis being implanted, the endocarditis recurred. During a third operation an aortic homograft was implanted, and after six months a fourth operation was performed for a pseudoaneurysm at the base of the homograft, in proximity to the anterior mitral valve leaflet. RESULTS: The diagnosis of PVE was confirmed by the presence of continuous fever, transesophageal echocardiography and growth of penicillin-resistant Staphylococcus epidermidis from the valve prosthesis. CONCLUSION: The implantation of all prosthetic valves is encumbered with a risk of endocarditis. Although silver has bacteriostatic actions, the advantages of silver-coated prostheses in the treatment of this condition have yet to be assessed in clinical trials.     

Surgical therapy of infective endocarditis

Therapy of infective endocarditis (IE) remains a particular challenge due to a relative high morbidity and mortality. Cardiac surgery is established as a cornerstone in therapy for native valve endocarditis (NVE) as well as for prosthetic valve endocarditis (PVE) and is required in 30% of patients with active IE. The basic aim of surgery in IE is the radical debridement of infected tissue and reconstruction of valve function either by reconstructive valve surgery or valve replacement. Indication for surgery depends on several clinical variables, the main indication remains heart failure due to severe heart valve defects or prosthetic valve dysfunction. Surgical therapy of NVE can be performed with good clinical results in the early and late follow-up. Surgical therapy of PVE is still associated with quite high mortality up to 80% in some risk groups. This indicates the particular importance of focus evaluation and antibiotic prophylaxis after primary surgery for infective endocarditis.     

Outpatient parenteral antimicrobial therapy (OPAT) service is associated with inpatient-bed cost savings

In a cardiology department, there are some patients that require long-term antibiotics, such as those with infective endocarditis or infected prosthetic devices. We describe our experience with intravenous antibiotic therapy for patients with cardiology diagnoses who require a period of antibiotics in our outpatient service during the period of the COVID-19 pandemic. A total of 15 patients were selected to have outpatient antibiotic therapy (age range 36 to 97 years, 60% male). A total of nine patients had infective endocarditis, four patients had infected valve prosthesis or transcatheter aortic valve implantation (TAVI) endocarditis, one patient had infected pericardial effusion while another had infected pericarditis. For these 15 patients there was a total of 333 hospital bed-days, on average 22 days per patient. These patients also had a total of 312 days of outpatient antibiotic therapy, which was an average of 21 days per patient. The total cost, if patients were admitted for those days, assuming a night cost £400, was £124,800, which was on average £8,320 per patient. Three patients were readmitted within 30 days. One had ongoing endocarditis that was managed medically and another had pulmonary embolism. The last patient had a side effect related to daptomycin use. In conclusion, outpatient antibiotic therapy in selected patients with native or prosthetic infective endocarditis appears to be safe for a selected group of patients with associated cost savings.Key words: antibiotics, infective endocarditis, outpatient therapy     

Evaluation and management of prosthetic valve endocarditis

Despite improved operative technique and sophistication in managing patients undergoing cardiac valve replacement, prosthetic valve endocarditis (PVE) remains a source of major morbidity (overall recent incidence 2.1%), and these patients have a high case-fatality rate (58% overall). Early PVE (less than 60 days postoperative) has a worse prognosis (78% case-fatality rate) and is usually caused by staphylococcal species, gram-negative rods, and fungi; whereas the case-fatality rate in late PVE is 46%, owing to the lower fatality of streptococcal species infections that tend to occur late. Risk factors that portend a poor clinical response to medical therapy alone include the presence of congestive heart failure, paravalvular leakage, systemic emboli, early PVE, nonstreptococcal etiology, aortic location in a nonheterograft valve, as well as persistent fever (> 10 days). Given the frequently dismal outcomes in the medical management of these patients, the case is made for early surgical intervention in most cases of PVE (except for late streptococcal disease), especially if any of the aforementioned risk factors are present.     

Right-sided Staphylococcus aureus endocarditis in intravenous drug abusers: two-week combination therapy

STUDY OBJECTIVE: To determine the efficacy of short-course combination regimens for selected cases of Staphylococcus aureus endocarditis in intravenous drug abusers. DESIGN: Open study of nafcillin and tobramycin or vancomycin and tobramycin administered for 2 weeks with no further therapy. SETTING: County hospital. PATIENTS: Consecutive sample of 53 intravenous drug abusers with relatively uncomplicated right-sided S. aureus endocarditis, defined by clinical and echocardiographic criteria, and without renal insufficiency, extrapulmonary metastatic infectious complications requiring prolonged therapy or surgery for cure, meningitis, methicillin-resistant organism, aortic or mitral valve involvement, or pregnancy. INTERVENTIONS: Nafcillin, 1.5 g intravenously every 4 hours, plus tobramycin, 1 mg/kg body weight intravenously every 8 hours, administered for 2 weeks. Vancomycin, 30 mg/kg per day intravenously, in two or three divided doses, was used instead of nafcillin for patients allergic to penicillin. MEASUREMENTS AND MAIN RESULTS: Forty-seven of 50 patients (94%; 95% CI, 87 to 99+) treated with the nafcillin and tobramycin combination were cured. Only 1 of 3 patients treated with vancomycin plus tobramycin (33%, 95% CI, 2 to 86) was cured. CONCLUSIONS: Selected patients with S. aureus endocarditis can be treated safely and effectively with a 2-week course of nafcillin plus tobramycin. Only one of three patients treated with vancomycin plus tobramycin was cured, but three patients are too few to define with confidence the efficacy of this regimen.     

Actinobacillus actinomycetemcomitans prosthetic valve endocarditis

Actinobacillus actinomycetemcomitans, a fastidious gram-negative bacillus, has been reported as the cause of prosthetic valve endocarditis in 11 patients. Two additional patients are reported and the literature is reviewed. All cases occurred greater than 1 year after implantation of the prosthesis. Six of the 13 patients had had recent dental work or had poor dentition. Three patients had received endocarditis prophylaxis. Ten of 13 were cured with antibiotics alone. Only one patient suffered from congestive heart failure, and only one had documented evidence of major systemic emboli during antimicrobial therapy. Valve replacement was necessary in only two during antimicrobial therapy. A actinomycetemcomitans should be considered as a possible etiologic agent in late prosthetic valve endocarditis, particularly when blood cultures are initially negative. A regimen of a beta-lactam antibiotic in combination with an aminoglycoside is recommended for 4-6 weeks. The excellent in vitro activity of the third-generation cephalosporins and rifampin promise new therapeutic options.