Mycobacterium kansasii
My·co·bac·te·ri·um kan·sa·s'i·i
Mycobacterium kansasii
A mycobacterium that may involve any body site, but primarily the lungs; dissemination is rare and is typically an opportunistic infection in immunocompromised (e.g., AIDS) or immuosuppressed (e.g., post-transplant) hosts.Clinical findings
Healthy host
• Pulmonary—Cough, sputum, weight loss, SOB, chest pain haemoptysis, fever or sweats.
• Cutaneous—Sporotrichosis-like with local lymphatic spread; lesions include nodules, pustules, verrucous lesions, erythematous plaques, abscesses, and ulcers.
Immunocompromised host
• Appears late in HIV disease, most commonly affecting the lungs, accompanied by fever, chills, night sweats, productive or nonproductive cough, weight loss, fatigue, dyspnoea, and chest pain. Nearly 20% of patients with HIV and M kansasii infection eventually develop disseminated disease.
• M kansasii meningitis, like M tuberculosis meningitis, has a high mortality rate despite appropriate antibiotic therapy.
• M kansasii bacteremia, pericarditis with cardiac tamponade, oral ulcers, chronic sinusitis, osteomyelitis, have been reported in AIDS patients.
• Disseminated M kansasii infection also occurs in other immunocompromised hosts (e.g., with myelodysplastic syndrome, haemodialysis) in whom cutaneous involvemenet has clinically (e.g., cellulitis, seroma) and histologically (e.g., absence of granuloma) aypical, which may delay the diagnosis.
Epidemiology
Traditionally regarded as an infection of those with a higher income and standard of living, it also affects those in lower socioeconomic strata.
Frequency
2.4 cases/105/year in the general population; 115 cases/105/year in those with HIV infection; 647 cases/105/year in those with AIDS.
Management
Rifampin, rifabutin, ethambutol, ethionamide, amikacin, streptomycin, clarithromycin, sulfamethoxazole, ciprofloxacin; a three-agent regimen is recommended.