Introduction and objectives Non-tuberculous mycobacterial (NTM) infections are being increasingly identified within adult and paediatric Cystic Fibrosis (CF) populations. They present a diagnostic and management challenge, requiring intensive treatment regimens with little literature on eradication success within children. In this retrospective study we describe a cohort of paediatric CF patients with NTM infection, examine treatment duration and eradication.
Methods All new isolates of NTM during a five year period (2011–15) were identified at a single tertiary paediatric CF centre with a population of 450 children. Groups were separated into Mycobacterium abscessus complex (MABSC), Mycobacterium avium complex (MAC) and other mycobacterial infections (M. kansasii, M. malmoense). Data on demographics and NTM treatment were collected and analysed. Eradication is defined as 4 clear samples at a year after stopping treatment.
Results 33 patients grew at least one new isolate of NTM: MABSC (n = 20, 5 of which grew other NTM species in temporally distinct episodes), MAC (n = 12) & other NTMs (n = 5, mainly M. kansasii). 51% female. Median age at 1st isolation 12.3 yrs (range, 4–17.3), and FEV1 79.5% predicted (50–116%). 10 (26%) initial isolates were from BAL. For MABSC: 4 (20%) had ABPA and 6 (30%) CFRD. All patients met ATS/IDSA criteria for diagnosis and were treated in accordance with national consensus guidelines. Spontaneous clearance was seen in 100% of other NTM infections. For data on clearance and treatment of MABSC and MAC, see Table 1. 9/14 who completed NTM treatment showed culture conversion at 3 months. Only 2 children with negative cultures at 3 months went on to have subsequent positive microbiology.
Conclusion This is the first report discussing treatment success for NTM in a large paediatric cohort. Although single centre, there is a similar incidence of NTM to that reported for adult CF populations. Spontaneous clearance is more common with MAC (42%) and other NTM infections compared to MABSC (10%). To date 53% of treated MABSC are considered eradicated 12 months post treatment. Early culture conversion appears to be linked with treatment success. Further studies are needed to identify if a lack of early clearance should identify children appropriate for further inpatient induction therapy.