Infectious Diseases Case of the Month
       
Chest X-ray

A thirty-six year old white female was admitted to Munson Medical Center in Traverse City, MI for progressive subacute pneumonia.

Previously healthy her first indication of illness had come two weeks previously when she developed left sided chest pain followed by the development of fevers and malaise. She was seen by her primary care physician three days after the onset of symptoms who prescribed levofloxacin 250 mg daily for likely pneumonia. A week into her illness she presented to the emergency room with ongoing symptoms including cough that was sometimes productive. An CXR suggested pneumonia (see image at top left). She was advised to increase her levofloxacin to 750 mg daily.

On day 14 of her illness (day 11 of levofloxacin) she was referred for admission to the hospital by her primary care physician as she had shown no clinical improvement and her CXR had significantly worsened (see middle image at left). She appeared moderately ill and had diminished breath sounds and crackles in her left lung. There were no skin lesions. A CT scan of her chest (not pictured) showed dense, nearly complete, consolidation of her left lung without apparent abscess or pleural effusion. At the time of admission her temperature was 98.7, BP 115/69, pulse 117. Admission labs included WBC 21.6, hgb 13, plts 502. Oxygen saturation was 98% on 3L O2 by nasal cannulum.

The patient was married, the mother of two young children, and worked as a medical transcriptionist. She had no HIV risks nor other known immunocompromising conditions. Other family members had not been ill nor had their two dogs. She and her family lived in rural northern Michigan (near Traverse City) and spent many weekends at a family lake property in Michigan's Upper Peninsula (map). The lake cabin was attached to a boathouse that was frequented by bats, and the family had noted an extensive amount of bat droppings in the boathouse. She had been very busy at the end of the school year taking her children on field trips to the shore of Lake Michigan and Mackinac Island but had otherwise not traveled out of the local area.

On admission to the hospital she was begun on IV piperacillin-tazobactam and vancomycin. Despite this she became progressively more ill with high fevers, shortness of breath, and the appearance of peri-hilar infiltrates in her right lung as well (see lower image at left). Blood cultures and sputum cultures were without significant growth, and urinary legionella and pneumococcal antigens were negative.

On the fourth hospital day she underwent bronchoscopy. Evidence of bronchitis was not found but there were copious thin greenish secretions. Specimens were obtained by protected brush and bronchoalveolar lavage and submitted to the lab for evaluation.

What organism was the cause of this patient's progressive pneumonia?
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What organism was the cause of this patient's illness?

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