Diagnosis: M. scrofulaceum
• Mycobacterium scrofulaceum is second to M. avium complex as the most common cause of cervical lymphadenitis in children. It can also present as cutaneous lesions.
• M. scrofulaceum is identified using routine biochemical assays, line probe assays, or gene sequencing. Although there are currently no commercially available probe tests for identification, this organism has a unique 16S rRNA sequence that is targeted for gene sequencing analysis.
• M. scrofulaceum is a slow-growing, yellow-pigmented, scotochromogen that tests negative for niacin and nitrate reduction and positive for the 68°C and semi-quantitative catalase tests.
• With the exception of rapidly growing mycobacteria, susceptibility testing for nontuberculous mycobacteria (NTM) is not standardized by the Clinical Laboratory Standards Institute (CLSI).
• Treatment for cervical lymphadenitis is surgical excision and/or treatment with clarithromycin combined with ethambutol or rifabutin.
