Quadricuspid aortic valve complicated with infective endocarditis: report of a case

Aortic valve fenestrations: Macroscopic assessment and functional anatomy study

Aortic valve fenestrations are defined as a loss of aortic valve leaflet tissue. They are a common but overlooked finding with unclear significance. The aim of this study was to investigate the varied functional anatomies of aortic valve fenestrations. A total of 400 formalin-fixed autopsied human hearts were macroscopically assessed and the function of the aortic valve of 16 reanimated human hearts were imaged using Visible Heart® methodologies. Aortic valve leaflet fenestrations were present in 43.0% of autopsied hearts (in one leaflet in 24.0%, in two leaflets 16.0%, in all leaflets 3.0%). Fenestrations were mostly present in left (25.5%) followed by right (23.3%) and noncoronary leaflet (16.3%). In 93.8% of cases, the fenestrations form clusters and were mainly located at the free edge of the leaflet in the commissural area (95.4%). Hearts with aortic valve fenestrations had significantly larger aortic valve diameters and aortic valve areas (p < 0.001). The average surface area sizes of fenestrations were 23.8 ± 16.6 mm² , and the areas were largest for left followed by right and noncoronary leaflet fenestrations (p < 0.001). The fenestration areas positively correlated with donor age (r = 0.31; p = 0.02). Significant hypermobility and subjective weakening of the leaflet adhesion levels of the fenestrated regions were observed. In conclusion, fenestrations of the aortic leaflets are frequent, and their sizes may be significant. They occur in all age groups, yet their size increase with aging. Fragments of leaflets with fenestrations show different behaviors during the cardiac cycle versus unchanged areas.

Corynebacterium striatum Endocarditis After Renal Transplantation Confirmed by Metagenomic Next-Generation Sequencing: Case Report and Literature Review

Background

Case Presentation

Conclusion

Quadricuspid aortic valve infective endocarditis

Infective endocarditis complicating a quadricuspid aortic valve (QAV) is rare. Previous reports highlight the increased risk for complications, including progressive aortic regurgitation, decompensated heart failure, and valve perforation. Thus, cardiologists must be able to quickly identify QAVs to guide rapid evaluation and treatment. We report a case of infective endocarditis in a QAV identified on echocardiography and effectively managed with medical therapy alone without complications over an 8-year follow-up period. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 46:145-148, 2018.

When Good Bugs Go Bad: Epidemiology and Antimicrobial Resistance Profiles of Corynebacterium striatum, an Emerging Multidrug-Resistant, Opportunistic Pathogen

Infections with Corynebacterium striatum have been described in the literature over the last 2 decades, with the majority being bacteremia, central line infections, and occasionally, endocarditis. In recent years, the frequency of C. striatum infections appears to be increasing; a factor likely contributing to this is the increased ease and accuracy of the identification of Corynebacterium spp., including C. striatum, from clinical cultures. The objective of this study was to retrospectively characterize C. striatum isolates recovered from specimens submitted as part of routine patient care at a 1,250-bed, tertiary-care academic medical center. Multiple strain types were recovered, as demonstrated by repetitive-sequence-based PCR. Most of the strains of C. striatum characterized were resistant to antimicrobials commonly used to treat Gram-positive organisms, such as penicillin, ceftriaxone, meropenem, clindamycin, and tetracycline. The MIC₅₀ for ceftaroline was >32 μg/ml. Although there are no interpretive criteria for susceptibility with telavancin, it appeared to have potent in vitro efficacy against this species, with MIC₅₀ and MIC₉₀ values of 0.064 and 0.125 μg/ml, respectively. Finally, as previously reported in case studies, we demonstrated rapid in vitro development of daptomycin resistance in 100% of the isolates tested (n = 50), indicating that caution should be exhibited when using daptomycin for the treatment of C. striatum infections. C. striatum is an emerging, multidrug-resistant pathogen that can be associated with a variety of infection types.

The left atrial bacterial vegetative mass due to Corynebacterium striatum as a presentation of myxoma: a case report

Background

Corynebacterium striatum is a member of the non-diphtherial corynebacteria, which are ubiquitous in nature and generally colonize the skin and mucous membranes of humans. Rarely, it causes infective endocarditis (IE). We report a case of rare left atrial bacterial vegetative mass due to C. striatum masquerading as a myxoma identified through a tortuous diagnostic process, and present a brief review of the relevant literature.

Case presentation

We present a case of 63-year-old man who presented with progressively worsening dyspnea on exertion and lower leg edema, and was diagnosed with heart failure. Transesophageal echocardiography (TEE) revealed that the left atrium was filled with a 2.7 cm × 2.6 cm mass. The patient, who had no signs of infection or related risk factors, was suspected of having a left atrial myxoma clinically. After excising the mass, the histopathology suggested thrombus with no myxocytes. Postoperatively, a fever appeared and C. striatum was isolated from the blood cultures. Although antibiotics were used, the symptoms of heart failure worsened gradually and echocardiography revealed valve vegetation. The patient underwent a second operation because of IE. Surprisingly, the mass was confirmed to be a bacterial vegetation due to C. striatum based on Gram staining at a 1000× magnification, although this was not noted on routine pathological examination of the two surgical specimens.

Conclusions

Physicians should be aware of Corynebacterium in blood cultures, which cannot simply be assumed to be a contaminant. A diagnosis of IE should be suspected, particularly in high-risk patients or those with an unexplained fever. Our patient had IE due to C. striatum with no risk factors. This case supports the diagnosis of IE using a combination of pathology and etiology.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2468-8) contains supplementary material, which is available to authorized users.

Corynebacterium striatum Bacteremia Associated with a Catheter-Related Blood Stream Infection

A 49-year-old woman visited our emergency department because of exertional dyspnea due to severe left ventricular functional failure. It progressed to disseminated intravascular coagulation and disturbance of consciousness on day 67 of admission. Gram-positive bacilli were detected from two different blood culture samples on day 67 of admission. An API-Coryne test and sequencing (1~615 bp) of the 16S rRNA gene were performed, and the strain was identified as Corynebacterium striatum. The bacterium was detected from the removed central venous catheter tip too, and the patient was diagnosed with catheter-related bloodstream infection by C. striatum. However, treatment was not effective, and the patient died on day 73 of admission.