Fatal necrotizing pneumonia due to a Panton-Valentine leukocidin positive community-associated methicillin-sensitive Staphylococcus aureus and Influenza co-infection: a case report

We describe a fatal case of necrotizing pneumonia in a patient co-infected with Influenza B and a community-associated, PVL-positive methicillin-susceptible Staphylococcus aureus (MSSA).Necrotizing pneumonia due to community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is increasingly reported in otherwise healthy individuals [1]. Several cases of community-associated pneumonia (CAP) have been attributed to methicillin-resistant strains such as the USA 300 epidemic CA-MRSA clone and are often associated with influenza virus infection or influenza-like illness (ILI) [2]. The USA 300 clone harbors the gene encoding Panton-Valentine leukocidin (PVL) [3], a pore-forming toxin that targets cells of the immune system [4]. Although the majority of CA-MRSA infections involving skin and soft tissue likely occur independent of PVL toxin production [5], PVL is required for lung tissue necrosis and inflammation as present in the rare, but frequently fatal, cases of necrotizing pneumonia[4,6]. We report here a fatal case of necrotizing pneumonia in a patient co-infected with Influenza B and a PVL-positive Staphylococcus aureus that in contrast to recent reported cases is methicillin-susceptible.A previously healthy 30 year old black woman went to her local emergency department on April 12, 2007 with a 4 to 5 day history of sore throat, chills, fever and shortness of breath. A chest radiograph was performed and read as clear, however detail was obscured by abundant overlying soft tissue. She was diagnosed with bronchitis and treated with intravenous antibiotics and steroids. She was discharged to home with a prescription for albuterol and azithromycin, however the antibiotic was not utilized. Early the following morning, she developed worsening symptoms including hemoptysis. She was brought to the emergency room by ambulance. Vital signs at time of admission included a fever of 100.5°F (38°C), pulse of 165 bpm, and blood pressure of 104/53 mm Hg. In the emerge