556 - Invasive bacterial infections by bacteria other than Escherichia coli and Streptococcus agalactiae in young febrile infants

Publication Number: 2541.556

Jose Antonio Alonso Cadenas, Hospital Infantil Universitario Niño jesús, Madrid, Madrid, Spain; María Suárez-Bustamante, Hospital Infantil Universitario Niño Jesús, Madrid, Madrid, Spain; Anna Sorolla Anglès, Hospital Sant Joan de Déu (Barcelona), Sabadell, Catalonia, Spain; Borja Gómez, Hospital Universitario Cruces, Barakaldo, Pais Vasco, Spain; Ana María Borrull-Senra, Hospital Sant Joan de Déu Barcelona, Barcelona, Catalonia, Spain; Susanna Hernández-Bou, Hospital Sant Joan de Déu Barcelona, Barcelona, Catalonia, Spain; Vanessa Bonil, Hospital Universitario de Terrassa, Barcelona, Catalonia, Spain; Cristina López, Hospital Universitario Marqués de Valdecilla, Santander, Cantabria, Spain; Lucia Garriga Ferrer-Bergua, Pediatric Emergency Department, Hospital Universitario de Canarias, Santa Cruz de Tenerife, Canarias, Spain; Laia Sanchez, Parc Sanitari Sant Joan de Déu, Sant Boi de Llobregat, Catalonia, Spain; Amaia Camara, Osakidetza, Donostia, Pais Vasco, Spain; Diana Martinez, Hospital Universitario de Navarra, Barañain, Navarra, Spain; Elena Granda, Río Hortega University Hospital, Valladolid, Castilla y Leon, Spain; María Concepción Villalón Martínez, Hospital Salamanca, Salamanca, Castilla y Leon, Spain; Rocio Rodrigo, n/a, Barcelona, Catalonia, Spain; Roberto Velasco, Hospital Universitari Parc Taulí, SABADELL, Catalonia, Spain

Background: Invasive bacterial infections (IBIs) in febrile infants younger than 90 days are mainly caused by Escherichia coli and Streptococcus agalactiae. IBIs caused by these prevailing bacteria have been extensively studied. However, infections caused by other bacteria remain less well characterized.

Objective: To describe the epidemiology, clinical characteristics, and adverse outcomes of IBIs caused by pathogens other than E. coli and S. agalactiae in febrile infants younger than 90 days.

Design/Methods: We conducted a subanalysis of a retrospective, multicenter study of febrile infants younger than 90 days presenting to the pediatric emergency departments of 12 Spanish hospitals between 2008 and 2022 and finally diagnosed with an IBI. For this subanalysis, we excluded those in whom the causative bacteria were E. coli or S. agalactiae. Demographic, clinical, laboratory, microbiological, and outcome data were collected using a standardized form.
IBI was defined as the isolation of a single bacterial pathogen in blood or cerebrospinal fluid. Adverse outcomes included the development of sepsis, acute complications, long-term sequelae, or death.

Results: Among 380 included infants with an IBI, 106 (27.9%) causes were caused by pathogens other than E. coli or S. agalactiae and were analyzed. Of these, 74 (69.8%) were diagnosed with isolated bacteremia, 20 (18.9%) with bacteremic urinary tract infection (UTI) and 12 (11.3%) with bacterial meningitis (one of them with an associated UTI).
The median age was 35 days (IQR 15-59), and 55% were male. In the emergency department, 18 of them (17.0%) presented with an altered pediatric assessment triangle. The most frequent pathogens were Staphylococcus aureus (28.3%), Streptococcus pneumoniae (14.2%), Enterococcus faecalis (13.2%), Klebsiella spp. (10.4%), and Neisseria meningitidis (9.5%). All isolated pathogens and their distribution across age groups are shown in Table 1.
Nine (8.5%) infants experienced one or more adverse outcomes, all were younger than 60 days of age: four developed sepsis, five had acute complications (three presented with seizures, and two required limb surgery), and two developed long-term sequelae related to kidney injury. No patients died. The rate varied according to the causative bacterium, as shown in Table 2, where the findings are detailed.

Conclusion(s): Non-E. coli and non-S. agalactiae IBIs are not rare in young febrile infants and can lead to severe outcomes, especially in those under 60 days of age. Clinicians should consider these pathogens when evaluating and managing febrile infants younger than 90 days.

Table 1. Pathogens isolated and their distribution across age groups.


Table 2. Adverse outcomes.
IBI, invasive bacterial infection; UTI, urinary tract infection.