# Legionella bozemanii lymphadenitis in an immunocompetent child and the role of sequencing in the diagnostic evaluation of culture-negative pediatric lymphadenitis: a case report

## TL;DR

A 3-year-old child with persistent lymph node swelling was diagnosed with Legionella bozemanii using sequencing after traditional tests failed.

## Contribution

First documented case of L. bozemanii causing lymphadenitis in an immunocompetent child.

## Key findings

- 16s rRNA sequencing identified L. bozemanii in a culture-negative pediatric lymphadenitis case.
- The child responded well to azithromycin therapy after diagnosis.
- Molecular methods are valuable for diagnosing refractory lymphadenitis cases.

## Abstract

Legionella species comprise a group of fastidious, intracellular, Gram-negative pathogens which are most associated with pulmonary disease, though extrapulmonary manifestations have been described. Some species, such as Legionella bozemanii, are thought to primarily affect immunocompromised hosts; however, prevalence may be underappreciated due to challenges in traditional culture-based detection methods.

This case report describes a 3-year-old healthy male who experienced subacute cervical lymphadenitis refractory to medical and surgical management. After initial debridement, he had no growth on aerobic, anaerobic, acid-fast bacilli, or fungal cultures, at which time 16s rRNA sequencing was sent from lymph node aspirate. Following discharge testing resulted positive for L. bozemanii, and he responded well to 1 month of oral azithromycin therapy.

To our knowledge, this is the first documented pediatric case of L. bozemanii both as a cause of cervical lymphadenitis and as a pathogen in an immunocompetent child. This case highlights the usefulness of molecular diagnostic methods in cases of refractory, culture-negative pediatric lymphadenitis and encourages increased diagnostic suspicion of Legionella species as causative agents of this disease.