Risk factors of non-tuberculous mycobacterial lymphadenitis in children: a case–control study

The aim of the present study is to clarify the association between environmental exposures and non-tuberculous mycobacterial (NTM) lymphadenitis, during the last decade, in a population of children. In children up to 14 years of age in a pediatric tertiary hospital, all cases of NTM lymphadenopathy with a specific microbiological diagnosis, from January 2004 to January 2015, were reviewed. This is a case–control study (1:5 proportion), in which the prevalence of environmental factors between cases and controls was compared by means of a multivariate logistic regression analysis. A total of 24 cases were diagnosed in the aforementioned period, and 18 of them included in the case–control study. Mycobacterium avium-intracellulare was the predominant mycobacterium species isolated (83.3%). Exposure to hens showed a clear trend to be significantly associated with the disease (OR = 4.33; IC95% 0.97–19.41, p = 0.055), with no significant differences for the rest of the risk factors studied. Conclusion : M. avium is still the predominant bacteria causing NTM lymphadenitis in children of our region. Contact with hens has been the only risk factor for NTM lymphadenitis detected in the present study. What is Known: • M. avium is the predominant bacteria causing NTM lymphadenitis in children of our region. • There is no consensus on which environmental factors are associated with NTM lymphadenitis in children. What is New: • The only risk factor for NTM lymphadenitis found in the present study was regular contact with hens. Contact with other farm animals was not associated to NTM lymphadenitis.