[Erythema nodosum as a first sign of adenitis due to Mycobacterium lentiflavum]

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.

Comparison of Mycobacterium lentiflavum and Mycobacterium avium-intracellulare complex lymphadenitis

BACKGROUND

Mycobacterium lentiflavum is considered a rare pathogen causing nontuberculous mycobacterial (NTM) lymphadenitis.

METHODS

A multicenter, retrospective study was performed in immunocompetent children <14 years of age with microbiologically confirmed NTM lymphadenitis treated at 6 hospitals in Madrid, Spain, during 2000-2010. We compared children with M. lentiflavum and Mycobacterium avium-intracellulare complex infection.

RESULTS

Forty-five microbiologically confirmed NTM lymphadenitis patients were identified: 19 (45.2%) caused by M. avium-intracellulare complex, 17 (40.5%) by M. lentiflavum, 1 by both and 5 by other mycobacteria. Out of 17 M. lentiflavum cases, 14 were diagnosed in the past 5 years. Regarding M. lentiflavum cases, median age was 23 months. Submandibular nodes were the most frequently involved (76.5%), with multiple locations seen in 41% of the children and spontaneous drainage in 41% of them. Drug susceptibility tests were performed in 14 isolates and showed a complete susceptibility to clarithromycin and cycloserine, whereas 93% were resistant to rifampin, 33% to quinolones and full resistance to other tested antimycobacterial drugs was detected. All but 1 child required surgery and 11 were treated additionally with various drug combinations. Total resolution was achieved in 50% of children within 6 months.Compared with M. avium-intracellulare complex cases, children were younger and laterocervical nodes were significantly less frequently involved. No statistically significant differences were found related to clinical characteristics, treatment and outcome.

CONCLUSIONS

M. lentiflavum is an emerging pathogen producing NTM lymphadenitis in Madrid.