Klebsiella pneumoniae subspecies rhinoscleromatis

Background

• Causative organism of rhinoscleroma, a chronic granulomatous disease of nasal and respiratory tract
• Also known as respiratory scleroma

Microbiology

• Subspecies of Gram-negative bacillus within the species Klebsiella pneumoniae

Epidemiology

• Not found outside of human hosts
• Primarily found in developing countries worldwide, in particular Mexico, Central America, and the Middle East
• Transmitted by close contact

Clinical Manifestations

• Non-specific early symptoms make it a challenging diagnosis
• Causes chronic inflammation of the nasal pathways and other parts of respiratory tract
• Starts with atrophic stage followed by granulomatous stage and finally fibrotic stage
• By the time it is diagnosed, it is often already quite disfiguring, with airway compromise
• Presents with nodules or masses in the nasal passages or other parts of the naso- or oropharynx or respiratory tract
• Can occasionally erode through bone to cause CNS infections

Differential Diagnosis

• Tuberculosis
• Leprosy
• Fungal infections
• Granolumatosis with polyangiitis
• Malignancy, including less commonly T cell lymphoma and basal cell carcinoma
• Sarcoidosis

Diagnosis

• Biopsy shows granulomatous inflammation with foamy macrophages (known as Mikulicz cells), which contain intracellular bacteria
• Grow in routine culture

Manageemnt

• Treated with 6 to 8 weeks of antibiotics (or longer), with or without surgical debridement, but high relapse rate
• Traditionally treated with streptomycin or tetracycline; more recently, may be treated with co-trimoxazole or [[[fluoroquinolones]]