Background
There are limited data on the epidemiology, diagnosis and optimal management of nontuberculous
mycobacterial (NTM) disease in children.

Methods
Retrospective cohort study of NTM cases over a 10-year-period at a tertiary referral hospital
in Australia.

Results
A total of 140 children with NTM disease, including 107 with lymphadenitis and 25 with skin
and soft tissue infections (SSTIs), were identified. The estimated incidence of NTM disease
was 0.6–1.6 cases / 100,000 children / year; no increasing trend was observed over the
study period. Temporal analyses revealed a seasonal incidence cycle around 12 months,
with peaks in late winter/spring and troughs in autumn. Mycobacterium-avium-complex
accounted for most cases (77.8%), followed by Mycobacterium ulcerans (14.4%) and
Mycobacterium marinum (3.3%). Polymerase chain reaction testing had higher sensitivity
than culture and microscopy for acid-fast bacilli (92.0%, 67.2% and 35.7%, respectively).
The majority of lymphadenitis cases underwent surgical excision (97.2%); multiple recurrences
in this group were less common in cases treated with clarithromycin and rifampicin
compared with clarithromycin alone or no anti-mycobacterial drugs (0% versus 7.1%; OR:0.73). SSTI recurrences were also less common in cases treated with two anti-mycobacterial
drugs compared with one or none (10.5% versus 33.3%; OR:0.23).

Conclusions
There was seasonal variation in the incidence of NTM disease, analogous to recently published
observations in tuberculosis, which have been linked to seasonal variation in vitamin
D. Our finding that anti-mycobacterial combination therapy was associated with a reduced
risk of recurrences in patients with NTM lymphadenitis or SSTI requires further confirmation
in prospective trials.