A 92-year-old Caucasian HIV-negative female presented with a 6-month history of a cough with yellow to brown sputum, involuntary loss of 2 kg with a generally slender body type, but no fever. The patient did not suffer from any other chronic condition and was HIV-negative. A chest radiograph showed a cavern in the right upper pulmonary lobe (Fig. 1A). In a CT scan the cavern had a 4.5 cm diameter in the right upper pulmonary lobe with accompanying infiltrations (Fig. 1B). Moreover, lymphadenopathy was found in the upper right hilum and in the mediastinum. Laboratory analyses revealed mildly elevated C-reactive protein (CRP) levels (41.3mg/L) and normal blood leukocytes. In the 1940's and 50's the patient was employed as a pediatric nurse and was exposed to patients with tuberculosis.
Indeed, microscopy analysis showed acid-fast bacilli in the sputum as well as in the bronchoalveolar lavage. However, the patient tested negative for a tuberculosis screening test, the interferon gamma release assay (T-SPOT) and M. tuberculosis complex DNA was not detected using amplification/PCR methods and culture analysis. Microbiological cultures revealed a Mycobacterium spp. infection and molecular genetic testing (GenoType Mycobacterium AS VER 1.0 , Hain-Lifescience) identified M. celatum.
Based on the above findings a standard antibiotic therapy of atypical mycobacteriosis including rifabutin, ethambutol and clarithromycin was started. Despite of the antibiotic treatment the patient is treatment patient's condition aggravated as she developed fever and fatigue. Additionally, CRP concentration in blood was rising. Drug susceptibility testing revealed a resistance against rifabutin (Table 1). Consequently, antibiotic therapy was adjusted using protionamid instead of rifabutin. Within two weeks, a clinical improvement was observed: the fever subsided and CRP levels decreased. The patient was therefore dismissed from the hospital. Antibiotic therapy was scheduled to continue for one year after sputum conversion. Unfortunately, the patient died at home ten weeks after the proper treatment was initiated. An autopsy was not performed due to the advanced age of the patient.