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Description
Bacteraemic infections caused by Staphylococcus aureus have been reported with increasing frequency, and have emerged as the leading cause of infective endocarditis in many regions of the world.1–3
Endocarditis is an inflammation of the inner layer of the heart, the endocardium, with involvement of the heart valves (native or prosthetic valves). Other structures that may be involved include the interventricular septum, the chordae tendineae, the mural endocardium or even intracardiac devices. Acute bacterial endocarditis is usually of sudden onset associated with high fever, fast heart rate, fatigue and rapid and extensive heart valve damage.
In August 2011, an 87-year-old non-diabetic woman suffering from a left heel decubitus ulcer, measuring approximately 7 cm × 7 cm, was admitted to hospital to optimise local treatment (figure 1). The patient had been suffering from fever and a burst haemorrhagic bladder on the left heel since a few days. Her medical history included a grade III aortic valve stenosis and a grade II mitral valve stenosis. As a result of a third-degree atrioventricular block she underwent a DDDR pacemaker implantation in 2004.
The necrotic heel decubitus ulcer extending to the muscle and the bone.
Physical examination showed a necrotic ulcer on the left heel extending to the muscle and the bone. Laboratory testing revealed a leucocytosis of 23.9 × 109/l and an elevated C-reactive protein (CRP) level of 26.34 mg/dl. The patient received 4.0 g piperacillin and 0.5 g tazobactam (tazonam; 4.5 g) in a 30 min intravenous infusion three times per day for 3 days, but on the fourth day after admission to hospital the patient collapsed in the bathroom, suffered sudden cardiac arrest as a result of ventricular tachycardia, and died.
Autopsy revealed an extensive septal, left anterior and posterior wall myocardial infarction. In addition, a huge pus-filled abscess more than 2 cm in size behind the heavily calcified posterior mitral leaflet was found (figure 2). Bacterial examination of the abscess material revealed infective mitral valve endocarditis caused by a methicillin-resistant S aureus being sensitive to only tetracycline, trimethoprim and gentamicin (figure 3).
The pus-filled abscess (marked by black arrows) behind the mitral valve with yellowish calcification in the border zone.
Histological examination of the mitral valve demonstrated severe calcification (coloured violet, black arrows) surrounded by chronic inflammation and bacterial lawn (white arrow, H&E staining, 200-fold magnification).
Learning points
Bacterial endocarditis is a life-threatening infectious disease.
An efficient local treatment strategy for open wounds and the choice of the most appropriate antibiotic treatment are important.
Footnotes
Competing interests None.
Patient consent Obtained.