Methicillin-resistant Staphylococcus aureus-related glomerulonephritis in a child

Methicillin-resistant Staphylococcus aureus-associated glomerulonephritis (MRSA-GN), a syndrome in which superantigens play an important role in the pathogenesis of the infection, has been well described in adult patients but not previously recognized in children. We report the case of a 6-year-old girl with MRSA-GN. She presented multiple malformations, including tracheal stenosis necessitating tracheotomy. She was admitted to our hospital because of acute pneumonia caused by a MRSA infection and was found to have proteinuria and abnormal renal function. MRSA was detected in her sputum, and this MRSA isolate produced toxic shock syndrome toxin-1, which acts as a superantigen and stimulates V beta 2(+) T cells. A blood test revealed that the number of circulating V beta 2(+) T cells expressing CD45RO, a marker of activation, was increased along with a concomitant elevation in the levels of serum immunoglobulins. Both are hallmarks of MRSA-GN. The eradication of MRSA using appropriate antibiotics resulted in the disappearance of the proteinuria; in contrast, corticosteroid treatment failed. To the best of our knowledge, this is the youngest patient to be diagnosed with MRSA-GN. In summary, there should be a high index of suspicion for MRSA-GN, even in the very young, in order to avoid the unnecessary use of immune suppressants in this context.