Mycobacterium gordonae infection: causes, symptoms, diagnosis, and treatment

Mycobacterium gordonae can cause cutaneous and visceral lesions, often in individuals with reduced immunity.


Causes

Mycobacterium gordonae is a common mycobacterium and is a slow-growing yellow scotochromogen, with smooth surface, mainly in soils, ground water, tap water, bottled water, unpasteurized milk, mucous membranes, urine, and gastric fluid.

Mycobacterium gordonae is a nonpathogenic mycobacterium, and the mycobacterium isolated from many specimens may be contamination but not a pathogen. Therefore, the results of positive culture should be carefully evaluated. The mycobacterium can infect the lungs, blood, bone marrow, and other organs in patients with positive HIV or severe immunodeficiency, such as CD4+ lymphocytes less than 100/μL.


Signs and Symptoms

After the traumatic skin is exposed to the soil, which is common in garden workers, nodules or skin granuloma can occur. If there is trauma in the cornea, keratitis can occur after contact with the bacteria. In patients with HIV infection, pulmonary infiltration or nodules, thin walled cavity, retroperitoneal infections, pyemia, urinary tract infections, or synovial fluid infections can occur. Acute respiratory distress syndrome (ARDS) can occur. Numerous colonies can be found in respiratory specimens that are repeatedly cultured, often when CD4+ cells are less than 50/μL. Patients present with fever, lasting for more than 2 weeks. Patients have response to effective antimycobacterial medications, and the chest infiltration slowly subsides.

Mycobacterium gordonae infection is a marker of severe immunosuppression in HIV patients. The differences in race, gender, and age of the infection are unclear.

Patients generally have a good prognosis, unless immunosuppression. The mortality rate is less than 0.1%.


Histopathology

Tuberculoid granuloma in the dermis can be seen. Generally, caseous necrosis is absent, positive results in acid-fast staining are visible, and the mycobacterium can be isolated by culture.


Diagnosis

On the basis of the skin lesions, histopathology, positive results in acid-fast bacilli tests and culture, and identification of mycobacterium, the disease can be diagnosed. Generally, positive blood culture can indicate an infection rather than colonization. Once the culture is positive, comprehensive clinical considerations are required.


Treatment

There is currently no effective unified treatment regimen. In vitro susceptibility testing suggests that clarithromycin, azithromycin, quinolones especially levofloxacin, and ethambutol can be used. Treatment should be continued until negative culture. It is unclear whether extended treatment can prevent recurrence after negative bacterial culture. The bacterium is resistant to isoniazid, pyrazinamide, and streptomycin. The effects of doxycycline, sulfamethoxazole, and trimethoprim against the bacteria are unclear.

The course of treatment that prevents recurrence is undetermined, and 3, 6, or 12 months of treatment are present. Short course of treatment may result in relapses, whereas long course of treatment can cause adverse effects. Monotherapy can cause resistance, and there is no clear evaluation data for the interval multidrug therapy.