Abstract
Background Infective endocarditis caused by coagulase-negative staphylococci (CoNS) is increasingly recognized in patients with prosthetic valves and intracardiac devices. Although traditionally considered low-virulence organisms, CoNS—particularly Staphylococcus epidermidis—can cause destructive prosthetic valve infective endocarditis through biofilm formation, antimicrobial resistance, and periannular extension. Management is challenging, and outcomes are poor when infection is refractory to medical and surgical therapies.
Case Report A 47-year-old female with a bioprosthetic mitral valve and multiple comorbidities, including stage 3B invasive ductal carcinoma, presented with cardiogenic shock, complete heart block, and multiorgan hypoperfusion. Echocardiography revealed severe biventricular dysfunction, severe aortic stenosis with regurgitation, and mobile echodensities on both the aortic and bioprosthetic mitral valves, as well as on intracardiac catheters. Blood cultures grew S epidermidis, confirming prosthetic valve infective endocarditis. Despite broad-spectrum antibiotics, mechanical circulatory support, and multidisciplinary evaluation, the patient remained in refractory cardiogenic shock and developed multiple cardioembolic cerebral infarcts, precluding definitive valve surgery. Given the extensive valvular involvement, neurologic complications, and failure of conventional therapies, orthotopic heart transplantation was pursued as a salvage strategy. The patient underwent successful transplantation on hospital day 40, followed by prolonged postoperative antimicrobial therapy and carefully tailored immunosuppression in the setting of active malignancy.
Conclusion This case highlights the aggressive potential of CoNS prosthetic valve infective endocarditis and underscores its diagnostic and therapeutic challenges. In select patients with intractable infection, extensive valvular destruction, and refractory cardiogenic shock, orthotopic heart transplantation may be a lifesaving option for definitive infection eradication when standard surgical approaches are not feasible.
INTRODUCTION
Infective endocarditis is a life-threatening microbial infection of the endocardial surface—most often the cardiac valves—typically caused by bacteria. Infective endocarditis is often seen in older male patients or in patients who engage in high-risk activities, such as intravenous drug use. Usually, the causal organism arises from the skin, oral cavity, or gastrointestinal tract, with Staphylococcus aureus the most common organism. Coagulase-negative staphylococci (CoNS), usually a normal part of the skin flora, can cause opportunistic infections and infective endocarditis in immunocompromised patients or in patients with prosthetic valves or intracardiac devices.1
We present a case of bioprosthetic mitral valve infective endocarditis that required cardiac transplantation for sterilization.
CASE REPORT
A 47-year-old female with a history of coronary artery disease, diabetes mellitus type 2, paroxysmal atrial fibrillation, bioprosthetic mitral valve replacement, hyperlipidemia, stage 3B invasive ductal carcinoma, and obstructive sleep apnea presented with altered mentation and shortness of breath. Initial workup demonstrated elevated brain natriuretic peptide of 1,991 pg/mL (reference range, <100 pg/mL) and lactic acid of 8.6 mmol/L (reference range, 0.5-2.0 mmol/L). Chest computed tomography (CT) revealed pulmonary edema and an incidental left ventricular aneurysm. The patient was hemodynamically unstable after developing complete heart block that degenerated into pulseless electrical activity requiring multiple rounds of cardiopulmonary resuscitation. Given her history of coronary artery disease and the development of cardiogenic shock, she was taken emergently for coronary angiogram and right heart catheterization. Coronary angiogram revealed nonobstructive coronary artery disease and hemodynamic measurements consistent with cardiogenic shock (Table 1). Impella CP (Abiomed, Inc) placement was attempted but was unsuccessful because of the patient's small-diameter iliac artery, likely the result of vasoconstriction from prior epinephrine administration. A temporary transvenous pacemaker and pulmonary artery catheter were placed, and the patient was transferred to a tertiary center for a higher level of care.
Hemodynamic Readings From Initial Catheterization at Outside Facility
Upon arrival at the tertiary center, an intra-aortic balloon pump was placed, and the patient's hemodynamic measurements improved (Table 2). Transthoracic echocardiogram (TTE) demonstrated severe left ventricular systolic dysfunction with ejection fraction of 23% (previously 35% to 40%). The patient had severe thickening of the aortic valve leaflets with increased peak velocity of 3.3 m/s, mean gradient of 29 mm Hg, and a calculated valve area of 0.4 cm2. Transesophageal echocardiogram (TEE) revealed severe aortic stenosis with moderate eccentric regurgitation, an echodensity associated with the aortic valve, and a 1.3-cm echodensity on the bioprosthetic mitral valve. In addition, a hypoechoic, thick-walled cavity located in the region of the mitral-aortic intervalvular fibrosa was concerning for periannular abscess. Multiple mobile linear echodensities observed in the right atrium and associated with the Swan-Ganz catheter and temporary pacemaker lead were judged to be thrombi. Positron emission tomography (PET)/CT demonstrated a large area of hypermetabolism in the region of the aortic and mitral valve.
Hemodynamic Readings From Secondary Right Heart Catheterization at Tertiary Facility
Vancomycin 15 to 20 mg/kg intravenous (IV) every 12 hours and meropenem 1 g IV every 8 hours were initiated for suspected bacterial endocarditis. The patient was evaluated by Oral Maxillofacial Surgery for odontogenic sources of infection. However, her dental examination was negative for caries or periodontal disease, which ruled out oral sources. Three sets of blood cultures (2 aerobic/2 anaerobic) were collected 24 hours apart, with results available in 48 hours. The first set of blood cultures was positive for Staphylococcus epidermidis. The next 2 sets of blood cultures were negative. After 72 hours of vancomycin and meropenem administration, the patient was transitioned to cefazolin 2 g IV every 8 hours because of penicillin allergy. No additional blood cultures were collected after 2 sets were negative.
Despite attempts at stabilization, the patient required multiple vasopressors to maintain adequate perfusion, including dobutamine 5 μg/kg/min, dopamine 10 μg/kg/min, norepinephrine 0.4 μg/kg/min, and vasopressin 0.03 U/min. Cardiothoracic Surgery recommended the Commando procedure, a technically challenging surgery involving aortic valve or root replacement and mitral valve replacement, along with reconstruction of the aortomitral fibrous body.
Four days into her hospitalization, the patient developed new right upper extremity motor deficits concerning for acute cardioembolic stroke from infective endocarditis. CT and magnetic resonance imaging of the brain demonstrated a subacute right frontal lobe infarct and multiple brainstem infarcts. Neurology recommended deferment of anticoagulation and antiplatelet agents because of the risk of hemorrhagic conversion which delayed the surgical intervention decision (Commando procedure vs orthotopic heart transplantation). The Commando procedure was ultimately rejected because of the patient's profound hemodynamic instability, ongoing high-dose vasopressor and inotropic dependence, and new multifocal ischemic strokes that collectively conferred a prohibitive perioperative risk. In addition, Cardiothoracic Surgery did not think reconstruction of aortomitral continuity was possible via a redo sternotomy in a patient with severely reduced left ventricular systolic function. Given these factors, the multidisciplinary team determined that orthotopic heart transplantation offered a more definitive and safer therapeutic strategy for infection control and hemodynamic recovery.
The patient was continued on cefazolin until surgery and underwent successful orthotopic heart transplantation on hospital day 40. Her preoperative hemodynamic readings are shown in Table 3.
Hemodynamic Readings Prior to Orthotopic Heart Transplantation
Postoperative immunosuppression was difficult because the patient's stage 3B invasive ductal carcinoma required chemotherapy. She was initiated on tacrolimus 2 mg twice daily, mycophenolate 1,000 mg twice daily, prednisone 40 mg daily, and basiliximab 20 mg IV on postoperative days 0 and 4, with prophylactic treatments for opportunistic infections. Cefazolin 2 g IV every 8 hours was continued for 30 days posttransplant for prophylaxis.
The patient was hospitalized for a total of 52 days. She continues regular follow-up with the advanced heart failure/transplant team and is doing well, without further cerebral complications following the heart transplantation.
DISCUSSION
This case illustrates the challenges in managing infective endocarditis in a patient with multiple comorbidities and refractory cardiogenic shock. The complex presentation of the patient, which included bacterial endocarditis with suspected cardioembolic infarcts and extensive valvular involvement, necessitated a multidisciplinary approach. Heart transplantation was selected as the preferred method for sterilization of infective endocarditis.
Pathogenesis of Coagulase-Negative Staphylococci
CoNS are typically considered low-virulence commensal organisms2 but are known to cause infective endocarditis, particularly in patients with prosthetic valves or cardiac devices.1,2 Even minor skin trauma, including peripheral IV sites, can introduce CoNS into the bloodstream and cause infective endocarditis. A central mechanism in CoNS infectivity is biofilm formation, particularly on bioprosthetic valves, annuloplasty rings, pacemaker leads, and other intravascular hardware. These biofilms provide mechanical stability as well as metabolic protection, limiting antibiotic penetration and shielding organisms from immune surveillance.2 S epidermidis, the most common CoNS species, is adept at producing these biofilms, whereas Staphylococcus lugdunensis, although less common, demonstrates markedly higher virulence, often mimicking the destructive behavior of S aureus.2 In severe cases, persistent infection and local invasion can culminate in valvular abscesses, periannular extension, and substantial myocardial inflammation.2
Diagnostic Challenges
Diagnosing CoNS infective endocarditis can be challenging, as CoNS bacteremia is often dismissed as contamination. High clinical suspicion, repeatedly positive blood cultures, and supportive clinical and echocardiogram findings are essential to confirm a true infection. The 2023 Duke-International Society for Cardiovascular Infectious Diseases criteria for infective endocarditis includes several updates to the Duke criteria, including direct intraoperative inspection for infective endocarditis as a key diagnostic criterion, even without full pathologic or microbiologic evidence; an updated list of typical causative microorganisms; techniques such as polymerase chain reaction, DNA sequencing, or fluorescence in situ hybridization for better identification; updates to risk factors/predisposing conditions such as prosthetic valves and pacing leads; and new diagnostic modalities such as PET scans.3 These updates provide a useful framework for diagnosing infective endocarditis and are particularly relevant in this case. Typical physical examination findings such as vascular phenomena (Janeway lesions, splinter hemorrhages, conjunctival petechiae) and immunologic phenomena (Osler nodes, Roth spots, glomerulonephritis) were notably absent in our patient. Based on the new guidance in the 2023 Duke criteria, our patient met 2 major criteria for infective endocarditis: positive blood cultures with a causative organism and positive echocardiographic findings of vegetations. Advanced imaging, such as TEE and PET/CT, is indispensable for evaluating suspected prosthetic valve infections. Compared to TTE alone, TEE and PET/CT have increased sensitivity for detecting vegetations and determining periannular extension and abscess formation.1 Together, these tools and frameworks help differentiate true CoNS infective endocarditis from contamination and guide management in complex, high-risk cases.
Therapeutic Challenges
CoNS infective endocarditis is often difficult to treat and manage and has a high mortality despite conventional therapies. Antibiotic resistance is a common challenge, with methicillin-resistant S epidermidis (MRSE) representing approximately 60% of isolates in cases of bioprosthetic valve infective endocarditis, complicating antibiotic selection.2,4 Additionally, CoNS complicate antibiotic therapy because of the formation of biofilms that adhere to both bioprosthetic and native valves, conferring additional protective factors against many antibiotics.2 Therefore, combination therapy and prolonged antibiotic courses are often needed to overcome the challenge of biofilms created by CoNS.2 Our patient received vancomycin and meropenem for 72 hours, followed by cefazolin for 35 days before transplantation. Medical therapy and surgery often need to be combined to provide mortality benefits to patients.2 However, for patients with extensive destruction of the valve annulus or dehiscence of the prosthesis, surgical options are limited.5,6
Role of Orthotopic Heart Transplantation
Orthotopic heart transplantation is considered a last-resort salvage option for infective endocarditis and is generally reserved for patients who have extensive fungal infections or refractory infections with abscess and myocardial destruction not amenable to medical therapy or conventional surgical interventions.5,6 Transplantation is commonly performed only after any extracardiac infections have been adequately controlled and blood cultures are negative.5 However, recurrent infective endocarditis has been seen in transplanted hearts, likely attributable to posttransplant immunosuppression.5 Therefore, careful coordination with the infectious disease and transplant teams is required to prevent future infections.6 Long-term survival largely depends on infection eradication and graft function after transplantation.5
Few case reports and case series examine the use of orthotopic heart transplantation as a treatment option for extensive infective endocarditis.5 For CoNS infective endocarditis specifically, the reports are even fewer; however, this pool grows larger each year as implantation of prosthetic material becomes more common. One such report by Borde et al details a case of prosthetic valve infective endocarditis caused by MRSE that failed to respond to repeated surgical interventions.4 The patient was treated with prolonged courses of multiple antibiotics, with treatment complicated by resistance to several antibiotics. The patient finally achieved blood culture negativity and underwent heart transplantation, followed by a 4-week course of postoperative antibiotic coverage. At 6 months posttransplant, the patient did not have any reported complications.4 Orthotopic heart transplantation has also been successfully performed for infective endocarditis caused by non-CoNS organisms, as demonstrated in the case series by Aymami et al in which 6 patients with infective endocarditis refractory to medical therapy and surgical interventions underwent transplantation.5 All 6 patients received postoperative antibiotics for either 2 or 6 weeks (in the presence of other complications or atypical bacteria), with only 1 patient experiencing transplant-related complications.5
Overall, the literature varies on antibiotic choice and length of treatment because of the various complications in different patient cases. However, the literature seems to agree on a few principles relative to considering heart transplantation as a treatment option: (1) infective endocarditis has failed to resolve with medical and operative therapies; (2) the patient has severe valvular damage, prosthesis dehiscence (if applicable), and/or congestive heart failure; and (3) repeat blood cultures show evidence of resolution or control of infection.4-6 All the reported cases highlight the importance of close collaboration with related specialties, such as infectious disease and transplant surgery teams.4-6
CONCLUSION
CoNS infective endocarditis can produce valvular destruction and severe complications comparable in severity to those seen with S aureus. This pathogenic potential is attributed to the ability of CoNS to create biofilms, confer high rates of antimicrobial resistance, and infect prosthetic valves. In the case of persistent, refractory infections, abscess formations, and severe heart failure, orthotopic heart transplantation can be considered as a salvage therapy when all other surgical options fail. The key to successful orthotopic heart transplantation and improved survival lies in early recognition of CoNS infective endocarditis; aggressive, targeted, and prolonged antibiotic therapy; and multidisciplinary collaboration. Although an exceptional and rarely used option, orthotopic heart transplantation can be lifesaving in carefully selected patients, particularly those with infection control achieved, irreversible structural cardiac damage, refractory heart failure, or failure of all conventional medical and surgical therapies. This case adds to a growing area of research for a rarely used treatment modality for CoNS infective endocarditis. More data will need to be reported in similar cases to provide a holistic and comprehensive view of the therapy.
This article meets the Accreditation Council for Graduate Medical Education and the American Board of Medical Specialties Maintenance of Certification competencies for Patient Care and Medical Knowledge.
ACKNOWLEDGMENTS
The authors have no financial or proprietary interest in the subject matter of this article.
- ©2026 by the author(s); Creative Commons Attribution License (CC BY)
©2026 by the author(s); licensee Ochsner Journal, Ochsner Clinic Foundation, New Orleans, LA. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (creativecommons.org/licenses/by/4.0/legalcode) that permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.
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