Sporotrichoid cutaneous infection by Mycobacterium abscessus

abscessus Sir, Mycobacterium abscessus is the most pathogenic and chemotherapy-resistant rapid-growing mycobacterium. It is an environmental mycobacterial species ubiquitous in soil and water causing a wide range of disease: most commonly localized infections of the skin and subcutaneous tissue, rarely pulmonary infections. A 48-year-old female patient presented to our department with reddish papular and nodular cherry-sized lesions following a linear distribution along the back of the left hand and arm. On admission, ill-defined erythematous nodules with purulent discharge were located on the left arm, which appeared swollen (Fig. 1). No other skin abnormalities or local lymphadenopathy were found, and the patient did not report signs or symptoms of arthritis, bursitis, or tenosynovitis. She was afebrile, with a heart rate of 75 beats/min and blood pressure of 120/ 80 mmHg, there were no systemic symptoms of infection, and all the systems were clinically normal. The patient had no background of immunosuppression or tuberculosis, and she denied having a history of previous cutaneous injury, injection, or surgical intervention. We asked the patient about her lifestyle and hobbies, and she mentioned having an aquarium with some fish in apparently good condition. Laboratory investigations revealed mild leukocytosis (11 240/ll, nv. 4000–10 000/ll), borderline antistreptolysin O titer (322 UI/ml, nv. < 200 UI/ml), elevated C-reactive protein (1.77 mg/dl, nv. < 1 mg/dl), and elevated erythrocyte sedimentation rate (42 mm/h, nv. M < 20 mm/h, F < 30 mm/h). Renal function tests were within normal limits. Tests for antibodies to human immunodeficiency virus, purified protein derivative skin test, and Widal test were negative. According to clinical and anamnestic data, an atypical mycobacteriosis infection was suspected; therefore, a needle aspiration biopsy of two of the most recent skin lesions was performed, and extracted material was subjected to both microbiological examination and molecular analysis. Acid-fast bacilli were detected by Ziehl–Neelsen staining (Fig. 2); caseous necrosis and eosinophil cells were also observed. Excisional biopsy was performed, and histological findings demonstrated pathology that ranged from nonspecific to suppurative or caseous granulomas. Standard drug therapy for non-tuberculous mycobacteria with doxycycline 100 mg twice daily and local rifamycin twice daily was started. In vitro culture on the Lowenstein Jensen medium, incubated at 30 °C, did not show any microbial growth after about 10 weeks’ incubation. Molecular diagnosis was based on the evaluation of the gene coding for the 65-kDa heat shock protein. The molecular test was carried out through a genus-specific polymerase chain reaction (PCR) targeting 65-kDa mycobacterial membrane protein gene followed by automated DNA-sequencing (ABI Prism 310 Sequencer; Applied Biosystems, Foster City, CA, USA). Standard microbiological techniques including culture and common mycobacterial PCRs did not reveal other mycobacterial pathogens. Routine laboratory tests did not show noteworthy alterations. According to both clinical pattern and laboratory and histological findings, a skin sporotrichoid atypical mycobacteriosis by M. abscessus was diagnosed. Because M. abscessus was isolated two months after induction of therapy, when a regression of the lesions had not yet been observed, the therapeutic regimen with doxycycline and rifamycin was carried on until the third month. At 4, 8, 12, 16, and 20 weeks, no concomitant skin lesion appeared and regression of the lesions was observed, leaving only a few scarred spots.