A case of necrotizing pneumonia caused by co-infection with influenza B and a Panton-Valentine leucocidin negative community acquired methicillin-resistant Staphylococcus aureus strain

摘要

A 63-year-old woman visited our hospital complaining of fever and dyspnea. Her inflammatory response was strongly positive, with hyperglycemia, severe hypoxia, a high level of procalcitonin, and an influenza B antigen-positive result. Chest computed tomography (CT) on admission showed multiple nodules with infiltrative shadows in the bilateral lung fields, and gram-positive coccus with phagocytosis by neutrophils was observed in a sputum sample. Although treatments using sulbactam/ ampicillin (SBT/ABPC) and azithromycin (AZM) plus peramivir were initiated, the clinical effect was poor due to the delay of administration of linezolid (LZD). Because methicillin-resistant Staphylococcus aureus (MRSA) was isolated from sputum, treatments were changed to LZD plus AZM. Molecular analysis of the MRSA isolate showed as follows: multilocus sequence typing (MLST) 8, staphylococcal cassette chromosome mec (SCCmec) typelV, spa type tl767, Panton-Valentine leucocidin (PVL)-negative, arginine catabolic mobile element (ACME)-negative, and toxic shock syndrome toxin-1(TSST)-l-positive. Influenza B and TSST-1 produced by community acquired MRSA (CA-MRSA) may have been involved in the formation of necrotizing pneumonia in this patient. However, she improved following the administration of peramivir and LZD.