A 75-year-old white male, weighing 65 kg, presented to our center with complaints of a 3-months history of fatigue, evening rise in body temperature, night sweats, unexplained weight loss of 5 kg, worsening dyspnea, cough and mucopurulent sputum. He was a current smoker (30 pack/years) and worked in a stone quarry up to 12 years before; he had a history of chronic catarrhal bronchitis, benign prostatic hypertrophy and an intestinal polypectomy. He denied performing spirometry and taking systemic or inhaled corticosteroids; a chest x-ray of 3 years before showed rarefaction of bronchovascular tree.
On examination, he was afebrile and reduced vesicular murmur and widespread rhonchi were heard on auscultation of the chest. Remainder of the physical examination was unremarkable.
Blood tests showed neutrophilic leukocytosis (white blood cells 16500/mL, 70% neutrophils), mild anemia (hemoglobin 11,4 g/dl), moderate increase in serum inflammatory markers (erythrocyte sedimentation rate 72 mm/h, C-reactive protein 20 mg/l). Plasma immunoglobulin, liver and renal function were in the normal range and HIV antibody testing was negative.
A spirometry test was performed, revealing a severe obstructive ventilation defect, post b2 agonist Forced Vital Capacity of 72% and Forced Expiratory Volume in one second of 46% predicted. The chest X-ray showed, bilaterally in the apical and subclavian regions, sclerosis and multiple nodules with cavitations (Fig. 1). The chest high resolution computed tomography (HRCT) was reported as following: "Multiple nodular opacities are recognized in the upper lobes, in the apical segments of the lower lobes and in subpleural location; small and regular central cavitations are there in some of these lesions. Multiple focal points of "tree in bud" and bronchiectasis, with prevalent cystic type, in both lung apices are also present. No significant mediastinal lymphadenopathy. These findings are consistent with chronic TB" (Fig. 2).
Three sputum samples on three different days were collected and submitted for the search of Mycobacteria spp. Specimen were digested and decontaminated according to Kubica procedure; sputum smears for acid-fast bacilli examination using Kinyoun staining and culture on solid (Lowenstein-Jensen) and liquid medium (Mycobacteria Growth Indicator Tube) were then prepared. The microscopic examination showed filamentous, slim, branched (mycelium and hyphae), blue-to-fuchsia colored (acid-alcohol variable) elements (Fig. 3). Nocardia spp. was suspected and confirmed by Gram staining (not shown) and blood agar culture (Fig. 4). Culture on Lowenstein-Jensen medium is showed in Fig. 5. All the previous exams were negative for M. tuberculosis.
Genotypic identification was performed by amplification and sequencing of a DNA fragment coding a rRNA 16S (Applied Biosystem, USA). Sequences were compared with the reference ones present in the GenBank database through BLAST and Nocardia cyriacigeorgica with 100% identity was identified.
Minimal inhibitory concentrations were determined on Mueller Hinton Agar following a 24 h incubation at 37  C (Etest, BioMerieux). Results were revised and interpreted according to CLSI criteria: amikacin 0.25 mug/mL; amoxicillin plus clavulanic acid (8 mug/mL); ceftriaxone (1 mug/mL); cefepime (2 mug/mL); ciprofloxacin (4 mug/mL); clarythromycin (4 mug/mL); imipenem (0.38 mug/mL); linezolid (0.50 mug/mL); tobramycin (0.047 mug/mL); trimethoprim plus sulfonamide (0.006 mug/mL).
Patient was then started on trimethoprim-sulfamethoxazole (160/800 one tablet twice per day) for 6 months. Following this, a rapid improvement of symptoms, regression of the purulent sputum and of the neutrophilic leukocytosis had been achieved. A second chest radiograph was performed 2 months later, showing an improvement of radiological findings too. A spirometry test was then repeated, confirming the suspect of COPD; specific therapy was started.
The patient gave an informed consent for the case report.
Chest HRCT scan showing multiple nodular lesions with cavitations in upper lung zone bilaterally.