A six-week antibiotic treatment of endocarditis with spondylodiscitis is not associated with increased risk of relapse: A retrospective cohort study

The impact of concomitant infective endocarditis in patients with spondylodiscitis and isolated spinal epidural empyema and the diagnostic accuracy of the modified duke criteria

Background

The co-occurrence of infective endocarditis (IE) and primary spinal infections (PSI) like spondylodiscitis (SD) and isolated spinal epidural empyema (ISEE) has been reported in up to 30% of cases and represents a life-threatening infection that requires multidisciplinary management to be successful. Therefore, we aimed to characterize the clinical phenotypes of PSI patients with concomitant IE and furthermore to assess the accuracy of the modified Duke criteria in this specific population.

Methods

We conducted a retrospective cohort study in consecutive SD and ISEE patients treated surgically at our University Spine Center between 2002 and 2022 who have undergone detailed phenotyping comprising demographic, clinical, imaging, laboratory, and microbiologic assessment. Comparisons were performed between PSI patients with IE (PSICIE) and without IE (PSIWIE) to identify essential differences.

Results

Methicillin-susceptible Staphylococcus aureus (MSSA) was the most common causative pathogen in PSICIE group (13 patients, 54.2%) and aortic valve IE was the most common type of IE (12 patients, 50%), followed by mitral valve IE (5 patients, 20.8%). Hepatic cirrhosis (p < 0.011; OR: 4.383; 95% CI: 1.405-13.671), septic embolism (p < 0.005; OR: 4.387; 95% CI: 1.555-12.380), and infection with Streptococcus spp. and Enterococcus spp. (p < 0.003; OR: 13.830; 95% CI: 2.454-77.929) were identified as significant independent risk factors for the co-occurrence of IE and PSI in our cohort. The modified Duke criteria demonstrated a sensitivity of 100% and a specificity of 66.7% for the detection of IE in PSI patients. Pathogens were detected more frequently via blood cultures in the PSICIE group than in the PSIWIE group (PSICIE: 23, 95.8% vs. PSIWIE: 88, 62.4%, p < 0.001). Hepatic cirrhosis (PSICIE: 10, 41.7% vs. PSIWIE: 33, 21.6%, p = 0.042), pleural abscess (PSICIE: 9, 37.5% vs. PSIWIE: 25, 16.3%, p = 0.024), sepsis (PSICIE: 20, 83.3% vs. PSIWIE: 67, 43.8%, p < 0.001), septic embolism (PSICIE: 16/23, 69.6% vs. PSIWIE: 37/134, 27. 6%, p < 0.001) and meningism (PSICIE: 8/23, 34.8% vs. PSIWIE: 21/152, 13.8%, p = 0.030) occurred more frequently in PSICIE than in PSIWIE patients. PSICIE patients received longer intravenous antibiotic therapy (PSICIE: 6 [4-7] w vs. PSIWIE: 4 [2.5-6] w, p < 0.001) and prolonged total antibiotic therapy overall (PSICIE: 11 [7.75-12] w vs. PSIWIE: 8 [6-12] w, p = 0.014). PSICIE patients spent more time in the hospital than PSIWIE (PSICIE: 43.5 [33.5-53.5] days vs. PSIWIE: 31 [22-44] days, p = 0.003).

Conclusions

We report distinct clinical, radiological, and microbiological phenotypes in PSICIE and PSIWIE patients and further demonstrate the diagnostic accuracy of the modified Duke criteria in patients with PSI and concomitant IE. In the high-risk population of PSI patients, the modified Duke criteria might benefit from amending pleural abscess, meningism, and sepsis as minor criteria and hepatic cirrhosis as major criterion.

Contribution of Positron Emission Tomography-Computed Tomography (PET/CT) to the Diagnosis of Endocarditis Due to an Infected Pacemaker Associated With Spondylodiscitis

The incidence of cardiac device-related endocarditis (CDRIE) is increasing, and its diagnosis and treatment may occasionally be problematic. Echocardiography is important for its diagnosis, and 18F-fluorodeoxyglucose positron emission tomography-computed tomography (PET/CT) may also be useful as a diagnostic procedure. A case of CDRIE due to an infected pacemaker is presented. In this case, blood cultures were repeatedly negative, and transesophageal ultrasound examination did not reveal signs of the disease. However, PET/CT revealed the infection. The causative organism was Corynebacterium spp, and this was finally identified by polymerase chain reaction of a sample of the device material. Eight weeks before the development of CDRIE symptoms, the patient had been empirically treated for spondylodiscitis caused by a non-identified organism. CDRIE and spondylodiscitis are closely associated infections. The present case of CDRIE was treated successfully with six weeks of combination antimicrobial treatment. PET/CT may contribute to CDRIE diagnosis by locating the site(s) of the infection, especially in cases that are ultrasound and culture negative.