A Case of Severe Pneumonia with Extensive Lung Abscesses Due to a Klebsiella Isolate Presumptively Identified as Klebsiella Pneumoniae Subsp. Rhinoscleromatis.

A 67-year-old woman was admitted with the chief complaints of sputum, fever, dyspnea, and malaise. Chest CT revealed a large mass shadow occupying the right middle and lower lobes with multiple nodular shadows in the left lung, and complete atelectasis of the right lung developed the following day. Gram-negative rods in the blood, sputum, and lung tissue were presumptively identified as the rare subspecies Klebsiella pneumoniae subsp. Rhinoscleromatis. The isolate exhibited a hypermucoviscous phenotype based on a positive string test, and PCR assays targeting rmpA and magA were positive. She required intubation and ventilation support. After endotoxin adsorption and antimicrobial treatment, the patient recovered from a fulminant clinical course through appropriate systemic management.