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Updated: May 7, 2026
Intradermal Inoculation of Mycobacterium avium in the Mouse Ear
Published on: July 3, 2025
Comparison of Mycobacterium lentiflavum and Mycobacterium avium-intracellulare complex lymphadenitis
Beatriz Jiménez-Montero1, Fernando Baquero-Artigao, Jesús Saavedra-Lozano
1From the *Department of Pediatrics, Hospital Infanta Sofía, San Sebastián de los Reyes; †Division of Pediatric Infectious Diseases, Hospital Universitario La Paz; ‡Division of Pediatric Infectious Diseases, Gregorio Marañón Hospital; §Division of Pediatric Infectious Diseases, Hospital Universitario 12 de Octubre; ¶Department of Pediatrics, Hospital Puerta de Hierro- Majadahonda; ‖Department of Pediatrics, Hospital de Getafe; and **Department of Microbiology, Hospital Universitario La Paz, Madrid.
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.
