Aortic rupture involving matrix metalloproteinases 8 and 9 during Staphylococcus aureus pneumonia

An 87-year-old man was admitted to Jikei University Hospital presenting with fever and fatigue. Physical examinations revealed inspiratory coarse crackles on the left lung field. A chest CT detected a tumour-like consolidation around the thoracic aorta (figure 1A). Biochemical examinations found a high number of white blood cells and elevated C-reactive protein level, and a diagnosis of pneumonia was made. Penicillin antibiotics (ampicillin/sulbactam) were administered. Two days later, methicillin-sensitive Staphylococcus aureus (MSSA) was detected in two sets of blood cultures. An echocardiogram showed no vegetation and a urine culture was negative. A sputum culture was unobtainable, but pneumonia was the only focus of infection for the MSSA. Penicillin antibiotics were continued, but the patient suddenly developed cardiopulmonary arrest …