Clinical Characteristics and Treatment Outcomes for Patients Infected With Mycobacterium Haemophilum

Pornboonya Nookeu; Nasikarn Angkasekwinai; Suporn Foongladda; Pakpoom Phoompoung

Disclosures

Emerging Infectious Diseases. 2019;25(9):1648-1652. 

In This Article

Results

A total of 21 patients were included in this study; 67% were women (median age 53 years, range 25–73 years). All 21 patients were immunocompromised. The most common concurrent condition was HIV infection (8 patients, 38%), followed by systemic lupus erythematosus (5 patients, 23.8%), γ-interferon autoantibody (2 patients, 9.5%), kidney transplantation (2 patients, 9.5%), diabetes mellitus (2 patients, 9.5%), ankylosing spondylitis (1 patient), and nephrotic syndrome (1 patient).

All HIV-infected patients except 1 had CD4 cell counts <200 cells/mm3. Among non–HIV-infected patients, those with systemic lupus erythematosus, kidney transplantation, and nephrotic syndrome received corticosteroids or other immunosuppressive agents.

The most common organ involved was skin and soft tissue (13 patients), followed by bone and joint (3 patients), central nervous system (CNS) (3 patients), eye (2 patients), and lymph nodes (1 patient). Two patients (1 with CNS involvement [no. 1] and 1 with bone and joint infection [no. 14]) had concomitant mycobacteremia. The most common cutaneous manifestation was an erythematous nodule that commonly occurred on the extensor surface of elbows, legs, and the auricular area (Figure 1). Of 7 skin biopsy specimens, granulomatous inflammation was the most common pathologic finding. Three patients who had CNS involvement had advanced HIV disease and CD4 cell counts <50 cells/mm3. We obtained computed tomography (CT) and magnetic resonance imaging findings for 3 patients with CNS involvement (Figure 2).

Figure 1.

Cutaneous manifestation in non–HIV-infected patients infected with Mycobacterium haemophilum, Bangkok, Thailand. A) Patient 9, B) patient 11, C) patient 12, D) patient 16, E) patient 17, F) patient 21.

Figure 2.

Imaging of brain and spine of 3 patients infected with Mycobacterium haemophilum who had involvement of the central nervous system, Bangkok, Thailand. A) Patient 1, axial T1-weighted magnetic resonance imaging scan with gadolinium showing enhanced nodule at left dorsal pons. B) Patient 2, axial contrast-enhanced computed tomography scan showing hypodensity lesions in both thalami and nodular enhancement at the bilateral basal ganglia. C) Patient 3, sagittal T1-weighted magnetic resonance imaging scan with gadolinium showing multiple enhancing nodules at dorsal pons and upper cervical cord.

We did not perform antimicrobial drug susceptibility testing on any bacterial isolate because of a failure of growth in solid medium. A total of 20/21 patients were treated with a combination of antimycobacterial agents. For 19 patients whose outcomes were available, 11 patients were cured, 1 patient improved with ongoing antimicrobial drug treatment, 3 patients required surgical excision after failure of medical therapy, 3 patients had a relapse of their infection after treatment discontinuation, and 1 patient died from disseminated disease after 1 month of therapy (Table).

The success rate of medical therapy for cutaneous infection was 80%. However, this rate was lower (50%) for bone, joint, and ocular infections. All patients with CNS diseases and involvement showed treatment failures.

The most commonly used regimen included a combination of macrolides and fluoroquinolones (3 patients, 14.3%) or these combined regimens with rifampin (9 patients, 42.9%). Combination therapy with macrolides and fluoroquinolones resulted in a success rate of 60% for treatment of cutaneous infection. Use of rifampin as the third drug for more severe cases also resulted in a modest (66%) success rate. Sulfamethoxazole/trimethoprim, doxycycline, and cycloserine were also replaced with rifampin, which showed clinically successful results. For 11 patients in whom antimicrobial drugs could be discontinued, the median duration of treatment was 12 months (range 3–12 months for skin and soft tissue infections, 6 months for bone and joint infections, and 12 months for lymphadenitis and eye infections).

The patient who died of disseminated M. haemophilum infection was a 25-year-old man who was given a new diagnosis of infection with HIV and had a CD4 cell count of 17 cells/mm3. He had diplopia for 1 month and a low-grade fever. Physical examination showed multiple left-sided cranial nerve palsies (V [trigeminal], VI [abducens], and VII [facial]) and lower motor neuron lesions. Magnetic resonance imaging of the brain showed multiple, abnormal, high-signal-intensity lesions on T2-weighted imaging with gadolinium, as well as nodular enhancement of the left dorsal pons, right ventral pons, mid pons, left cerebellar peduncle, and medulla (Figure 2, panel A). Examination of cerebrospinal fluid showed standard results; hemoculture grew M. haemophilum. He was given levofloxacin, azithromycin, and ethambutol. However, his clinical condition deteriorated rapidly. Right hemiparesis then developed and he became stuporous. He died from acute respiratory failure secondary to aspiration pneumonia.

When we compared HIV-infected and non–HIV-infected patients, HIV-infected patients were younger (median age 36 years vs. 57 years; p = 0.017), more likely to have disseminated infection (37.5% vs. 15.4%; p = 0.325), more likely to have CNS involvement (37.5% vs. 0%; p = 0.042), and more likely to have a less favorable prognosis (50% vs. 77%; p = 0.38).

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