Disseminated cutaneous mycobacteria abscessus infection in a patient with chronic renal failure

Sir,

Mycobacterium abscessus, a type of non-tuberculous mycobacteria, is transmitted by inhalation, ingestion, or percutaneous penetration resulted in pulmonary, lymph node, or skin diseases. Disseminated cutaneous infection with M. abscessus is rare and easily misdiagnosed. Here, we described a mid-aged man with chronic renal failure presented with disseminated cutaneous nodules and abscesses.

A 53-year-old Chinese man presented to our hospital with a three-month history of disseminated cutaneous dark red nodules. These nodules were painless with a little itch. He suffered from chronic renal dysfunction and had been on hemodialysis for 9 years. Three months back, he underwent central venous catheterization in the right subclavian vein and then presented with a recurrent low-grade fever so far. He was a farmer without special contact history and family history of this disorder.

Physical examination revealed several reddish nodules, 2–4 cm in diameter, slightly elevated above the skin and scattered on trunk and limbs [Figure 1]. There were tenderness and firm on palpation. Lymph node examination was normal. Laboratory examination showed leukopenia (2.1×10⁹/L) and elevated serum creatinine (735μmol/L). Serological examinations for human immunodeficiency virus (HIV) were negative. Skin biopsy from the nodule revealed a large abscess in dermal companied by tissue necrosis, neutrophils, lymphocytes, scattered histiocytes and multinuclear giant cells [Figures 2a and b]. Acid-fast bacilli were identified in acid-fast staining [Figure 2c]. Samples at the biopsy site were collected for culture and pinpoint colonies grew after incubation at 37°C for 72 h on blood agar plate. They grew to white rough colonies and approximately 0.5 mm in diameter after seven-day incubation [Figure 2d]. They also grew well on MacConkey plate and catalase testing was positive. It was identified to be Mycobacterium abscessus using Hsp65 and rpoB gene sequence analysis. A diagnosis of disseminated cutaneous M. abscessus infection was made. Consequently, according to antibiotic susceptibility test results, this patient was under anti-mycobacterial treatment including rifampicin (450 mg/d), moxifloxacin (400 mg/d), clarithromycin (500 mg/d) and nadifloxacin cream (external use at skin ulcers). Blood routine examination, liver and renal function tests were monitored monthly. The lesions started resolving after eight weeks and involuted significantly after six months of treatment. This patient is still at follow-up.

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Figure 1a:

Multiple dark red nodules on the right arm

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Figure 1b:

Multiple dark red nodules on both legs

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Figure 1c:

Multiple dark red nodules on trunk and central venous catheterization can be seen in the right subclavian vein

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Figure 2a:

Histopathological examination in low-power view revealed a large abscess companied by tissue necrosis and inflammatory cells (H and E, ×100)

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Figure 2b:

Histopathological examination in high-power view revealed abundant neutrophils, lymphocytes, scattered histiocytes and multinuclear giant cells in lesion (H and E, ×400)

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Figure 2c:

Several reddish bacilli (arrow) were identified in tissue (acid-fast, ×400)

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Figure 2d:

Tissue culture showed white rough colonies on culture plate after 1 week

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M. abscessus was reclassified as a separate species in year, 1992. It which can contaminate inadequately sterilized medical instruments, causing serious postsurgical skin and soft-tissue infections.¹ Disseminated cutaneous M. abscessus infection is rare and particularly happens in immunocompromised or postoperative patients, usually presenting as multiple erythematous subcutaneous nodules on distal limbs or in a sporotrichoid pattern.²

M. abscessus infection is often concealed and chronic which is easily misdiagnosed. Clinical differential diagnosis includes cutaneous tuberculosis, bacterial infection and systemic vasculitis. Pathological examination and repeated culture of tissue are significance to make a define diagnosis. Colonies of M. abscessus have two morphology types that rough type has more virulence and is easier to cause persistent infection than smooth type.¹ PCR detection of the 16S–23S rRNA gene internal transcribed spacer sequences can be performed to differentiate from other mycobacteria infection. Because M. abscessus appears to be the most resistant species to conventional anti-tuberculous drugs, drug sensitivity tests in vitro are important to select rational treatments.¹ Macrolide antibiotics such as clarithromycin or azithromycin are recommended oral drugs for long-term treatment. Excision and debridement may be required for abscesses and ulcers. Review of literatures on M. abscessus infection with cutaneous manifestations is shown in Table 1.^3-8

In summary, we reported a rare case of disseminated cutaneous M. abscessus infection presented with multiple nodules and abscesses in a patient with chronic renal failure. Since hemodialysis and central venous catheterization are necessary to these patients, it is important to be aware of immunocompromised state and the risk of disseminated infection caused by rare opportunistic pathogens.