Page 91 - SAHCS HIVMed Journal Vol 20 No 1 2019

Page 4 of 6 Case Report

Other diseases that may be associated with M. genavense patient, ethambutol was given for a total of 10 months as part
infection include sarcoidosis, hyper-IgE syndrome and auto- of the initial treatment. Older literature refers to the use of
immune disorders (systemic lupus erythematosus and clofazimine. 30,31,32 This drug was used less frequently for the
myasthenia gravis). 9,24,25,26,27 treatment of disseminated non-tuberculous mycobacterial
disease after a clinical study found that clofazimine in
While most patients with M. genavense infection have combination with clarithromycin and ethambutol was
immunological pathology, a case of disseminated M. genavense associated with increased mortality in disseminated M. avium
infection in a healthy Japanese boy has also been described. complex infections in patients with AIDS. The use of
33
Computed tomography of the abdomen showed intestinal prednisone has been advocated to reduce local inflammation
wall thickening from the ileocecum to the ascending colon, as and compressive effects of the affected organs. In one study,
well as small intestinal dilation and ascites. The only possible it was used for 10 months. A case series where steroid
6
risk factor appeared to be exposure to pets, including dogs, therapy was included did not describe worse outcomes. 27
rabbits, turtles and tropical fish. 28
Treatment duration and follow-up
The clinical presentation of cases with M. genavense appears The documented cases of M. genavense disease indicate that the
mostly to be disseminated involving abdominal organs. Less duration of treatment should be prolonged to more than 12–27
common presentations include pleuropulmonary, cutaneous, months. 10,21 To make recommendations on the termination of
central nervous system and genital tract involvement. 9,29 treatment for these cases is therefore challenging. Due to the
Pulmonary involvement may include cavitations and fastidious nature of the mycobacterium, treating cases until
reticular–nodular infiltrates on chest X-ray. A few cases of 12 months culture negativity is problematic and treating for as
8
pulmonary M. genavense disease have been documented. 20
long as the immunodeficiency is present has resulted in life-
long treatment in some patients. Mycobacterial blood culture
20
The laboratory diagnosis of M. genavense infections usually
relies on detection by molecular methods. Mycobacterial 16S (with prolonged incubation) and stool AFB where appropriate
rRNA sequence analysis is often used for the confirmation of may be of value as markers of treatment response.
the diagnosis. 9,10 The GenoType Mycobacterium AS line
probe assay (Hain Lifescience, Nehren, Germany) can also be Follow-up radiological investigation, especially if CT is used,
used, but it cannot distinguish between M. genavense and increases the risks associated with radiation exposure. Some
Mycobacterium triplex. It is validated for use on cultured authors suggest an X-ray and high-resolution CT at baseline
34
material. We ran this line-probe assay method directly on the prior to the commencement of therapy. Follow-up radiology
34
duodenal biopsy according to the standard GenoType should be considered together with clinical assessment.
MTBDRplus protocol and were able to generate an Follow-up with repeat biopsies from the affected organs
interpretable banding pattern in our patient. to compare with initial histology reports might be another
6
option ; although as granulomas persist much longer than the
Treatment infection/disease, this might be a poor marker of response.
Rebiopsy for histology and culture may be considered when
In vitro susceptibility data are limited because of the treatment failure is suspected.
extreme fastidiousness of the organism, requiring special
supplementation, an acid pH and prolonged incubation. Complications
8,9
Available data suggest that most isolates are susceptible
to macrolides, rifamycins, fluoroquinolones and A poorly understood pathogen-specific syndrome similar to
aminoglycosides (amikacin and streptomycin). Mycobacterium retractile mesenteritis has been described in patients infected
8
genavense is resistant to isoniazid. Optimal therapy is not with M. genavense where chronic fibrosing inflammation is
9
determined. In animal models, a reduction in AFB burden is found in the small bowel mesentery. Rarely, chylous ascites
8
4,6
seen after 15–30 days with clarithromycin and rifampicin and may develop. Persistent relapsing infection may occur in
after 30 days with amikacin and ethambutol. A three- or patients with profound immunosuppression and high HIV
10
four-drug regimen is typically suggested. In one case series, viral loads at initial diagnosis with a large inoculum of
6
a regimen including a macrolide, ethambutol and often M. genavense organisms. A case of an HIV-infected paediatric
rifampicin recorded a favourable outcome in 75% of cases patient with intestinal lymphangiectasia and protein-losing
20
(9/12). In another case series, the survival rate at 1 year was enteropathy has been described. This patient presented
72%. In this case series, a treatment regime typically included with severe hypogammaglobulinaemia and moderate
clarithromycin, ethambutol and rifabutin, and sometimes hypoalbuminaemia. Lymphatic vessel dilatation, small
also a fluoroquinolone or amikacin. 27 intestinal wall thickening, ascites as well as retroperitoneal
and mesenteric adenopathy were seen on abdominal
Multidrug therapies that include clarithromycin appear magnetic resonance imaging. Elevated α-1 antitrypsin in
13
8
to be more effective than those without clarithromycin. stool confirmed the diagnosis of protein-losing enteropathy.
Ethambutol, despite limited in vitro activity against A similar scenario was reported by Tassone and colleagues.
21
M. genavense, 8,12 is included in treatment regimens of many Hyperammonemia was described in a renal transplant case
documented cases of M. genavense infections. 20,27 In our with disseminated M. genavense infection. 35
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