Legionellosis in young children: Literature review and case reports

Legionellosis is a bacterial infection that affects the respiratory tract, lung tissue, and a number of other organs and systems. Legionella pneumonia is characterised by the most severe course, in most cases accompanied by extensive inflammation. Despite the relative rarity of the pathology, especially in young patients, cases of Legionnaires' disease pneumonia in paediatric practice are of considerable scientific and clinical interest. Their thorough study is crucial for improving early diagnosis, optimising treatment, and shifting the clinical spectrum towards a predominance of mild forms of the disease. The aim of this study is to summarise current data on Legionnaires' disease and to present two clinical observations of Legionnaires' pneumonia. Аn analysis of the medical records of the only two cases of confirmed Legionnaires' disease in children aged 10 months and 2.5 years in the last 3 years, who were hospitalised in a multidisciplinary children's hospital with an infectious disease profile, was carried out; The world medical literature on Legionnaires' disease was studied using search engines and databases such as eLibrary, PubMed, ResearchGate, Google Scholar, and Scopus.

1. American Academy of Pediatrics. In: Kimberlin DW, Barnett ED, Lynfield R, Sawyer MH, eds. Red Book: 2021 Report of the Committee on Infectious Diseases. Itasca, IL: American Academy of Pediatrics: 2021:465-468.

2. Romanov KA, O'Connor TJ. 2024. Legionella pneumophila, a Rosetta stone to understanding bacterial pathogenesis. J Bacteriol. 206:e00324—24. DOI:10.1128/jb.00324-24

3. Tata A, Marzoli F, Cordovana M, Tiengo A, Zacometti C, Massaro A et al. A multi-center validation study on the discrimination of Legionella pneumophila sg.1, Legionella pneumophila sg. 2—15 and Legionella non-pneumophila isolates from water by FT-IR spectroscopy. Front Microbiol. 2023; 14:1150942. DOI: 10.3389/fmicb.2023.1150942

4. Stephanie Cargnelli, Jeff Powis and Jennifer L. Y. Tsang. Legionella pneumonia in the Niagara Region, Ontario, Canada: a case series. Cargnelli et al. Journal of Medical Case Reports. 2016; 10:336 DOI: 10.1186/s13256-016-1105-2

5. Infectious diseases in children: textbook. Ed V.F. Uchaykin, O.V. Shamsheva. 3rd ed. Moscow: GEOTAR-Media, 2022:920. (in Russ.)

6. Lupia, T., Corcione, S., Shbaklo, N., Rizzello, B., De Benedetto, I., Concialdi, E., et al. Legionella pneumophila Infections during a 7-Year Retrospective Analysis (2016—2022): Epidemiological, Clinical Features and Outcomes in Patients with Legionnaires’ Disease. Microorganisms. 2023; 11:498. DOI: 10.3390/microorganisms11020498

7. Lee M. Hampton, Laurel Garrison, Jessica Kattan, Ellen Brown, etc. Legionnaires’ Disease Outbreak at a Resort in Cozumel, Mexico. Open Forum Infect Dis. 2016;3(3):ofw170. DOI: 10.1093/ofid/ofw170

8. Perez Ortiz, A.; Hahn, C.; Schaible, T.; Rafat, N.; Lange, B. Severe Pneumonia in Neonates Associated with Legionella pneumophila: Case Report and Review of the Literature. Pathogens. 2021; 10:1031. DOI: 10.3390/pathogens10081031

9. Satoshi Kutsuna, Hiroyuki Ohbe, Naoki Kanda, Hiroki Matsui, Hideo Yasunaga. Epidemiological Analysis of Legionella Pneumonia in Japan: A National Inpatient Database Study. J Epidemiol. 2024; 34(8):365—371. DOI: 10.2188/jea.JE20230178

10. Gruzdeva O.A., Filatov N.N., Tartakovsky I.S., and Maryin G.G. Epidemiological Features of Legionellosis in the Russian Federation. Epidemiology and Infectious Diseases. 2017; 22(2). (in Russ.) DOI: 10.17816/EID42633

11. Kostic, A.; Cukovic, K.; Stankovic, L.; Raskovic, Z.; Nestorovic, J.; Savic, D.; et al. The Different Clinical Courses of Legionnaires’ Disease in Newborns from the Same Maternity Hospital. Medicina. 2022; 58:1150. DOI: 10.3390/medicina58091150

12. Eisenreich W, Heuner K. The life stage-specific pathometabolism of Legionella pneumophila. FEBS Lett. 2016 Nov; 590(21):3868—3886. DOI: 10.1002/1873-3468.12326

13. Torres-Escobar A, Wilkins A, Juárez-Rodríguez MD, Circu M, Latimer B, Dragoi AM, et al. Iron-depleting nutritional immunity controls extracellular bacterial replication in Legionella pneumophila infections. Nat Commun. 2024 Sep 8;15(1):7848. DOI: 10.1038/s41467-024-52184-x

14. Lanternier F, Ader F, Pilmis B, Catherinot E, Jarraud S, Lortholary O. Legionnaire's Disease in Compromised Hosts. Infect Dis Clin North Am. 2017 Mar; 31(1):123—135. DOI: 10.1016/j.idc.2016.10.014

15. Bienvenu A, Martinez E, Bonazzi M. Undercover Agents of Infection: The Stealth Strategies of T4SS-Equipped Bacterial Pathogens. Toxins (Basel). 2021 Oct 9;13(10):713. DOI: 10.3390/toxins13100713

16. Vázquez Marrero VR, Doerner J, Wodzanowski KA, Zhang J, Lu A et al. Dendritic cells activate pyroptosis and effector-triggered apoptosis to restrict Legionella infection. mBio. 2025 Jul 9;16(7):e0125725. DOI: 10.1128/mbio.01257-25

17. Lopez AE, Mayoral J, Zheng H, Cianciotto NP. Legionella pneumophila IrsA, a novel, iron-regulated exoprotein that facilitates growth in low-iron conditions and modulates biofilm formation. Microbiol Spectr. 2025 Jan 7;13(1):e0231324. DOI: 10.1128/spectrum.02313-24

18. Alzahrani N, Monir RL, Patel PA, Fox TG, Gonzalez MD, Lawley L. Cutaneous legionellosis in an immunocompromised neonate. Pediatr Dermatol. 2024 Nov-Dec; 41(6):1241-1243.DOI: 10.1111/pde.15702

19. Viasus D, Gaia V, Manzur-Barbur C, Carratalà J. Legionnaires' Disease: Update on Diagnosis and Treatment. Infect Dis Ther. 2022 Jun;11(3):973— 986. DOI: 10.1007/s40121-022-00635-7

20. Bai L, Yang W, Li Y. Clinical and Laboratory Diagnosis of Legionella Pneumonia. Diagnostics (Basel). 2023 Jan 12;13(2):280. DOI: 10.3390/diagnostics13020280

21. Graf, G.; Vassalli, G.A.M.; Kottanattu, L.; Bianchetti, M.G.; Agostoni, C.; Milani, G.P.; et al. Acute Pancreatitis Associated with Atypical Bacterial Pneumonia: Systematic Literature Review. J. Clin. Med. 2022, 11, 7248. DOI: 10.3390/jcm11237248

22. Diallo K, Rivière M, Gutierrez B, Andry F, Bertolotti A, Zemali N, et al. Cerebellar syndrome associated with legionellosis: A case report and literature review. Rev Med Interne. 2022 Jul; 43(7):440—443. DOI: 10.1016/j.revmed.2022.04.023

23. Moran A, Otero Espinal DE, Parilla M, Beavis KG, Mullane KM, Tesic V. Expect the unexpected: endocarditis caused by Legionella feeleii. Lab Med. 2024 Nov 4; 55(6):791—794. DOI: 10.1093/labmed/lmae029

24. Horie H., H Kawakami, K Minoshima, T Kamohara, T Nakamura, H Kuroki, et al. Neonatal Legionnaires' disease. Histopathological findings in an autopsied neonate. Acta Pathol Jpn. 1992;4 2(6):427—31.

25. Barton M, McKelvie B, Campigotto A, Mullowney T. Legionellosis following water birth in a hot tub in a Canadian neonate. CMAJ. 2017 Oct 23;189(42):E1311—E1313. DOI: 10.1503/cmaj.170711

26. Wei SH, Chou P, Tseng LR, Lin HC, Wang JH, Sheu JN et al. Nosocomial neonatal legionellosis associated with water in infant formula, Taiwan. Emerg Infect Dis. 2014 Nov; 20(11):1921—4. DOI: 10.3201/eid2011.140542

27. Jong B, Hallström LP. European Surveillance of Legionnaires' Disease. Curr Issues Mol Biol. 2021; 42:81—96. DOI: 10.21775/cimb.042.081

28. Anwar AI, Lu L, Plaisance CJ, Daniel CP, Flanagan CJ, Wenger DM et al. Fluoroquinolones: Neurological Complications and Side Effects in Clinical Practice. Cureus. 2024;16(2):e54565. DOI: 10.7759/cureus.54565

29. Cattan S, Thizy G, Michon A, Arlet JB, Lanternier F, Lebeaux D, et al. Actualités sur les infections à Legionella [Legionella spp: An update]. Rev Med Interne. 2019 Dec; 40(12):791—798. French. DOI: 10.1016/j.revmed.2019.08.007