This study aimed to determine the prevalence of serious bacterial infections (SBIs) in infants less than 90 days old presenting with fever on arrival at the emergency department (ED), and to assess the diagnostic management of febrile infants.

A retrospective study at Mamoudzou Hospital, Mayotte Island, French Department.

General ED in the only pediatric hospital throughout the territory

We included infants less than 90 days old with a history of fever and bacterial investigation evaluated in the ED between 2016 and 2018. We excluded preterm infants (gestational age < 37 weeks) and those with known immunodeficiency or previous administration of antibiotics.

A total of 594 infants were included. In all, 105 infants (17.7%) were diagnosed with an SBI and 28 (4.7%) with an invasive bacterial infection of which 1.34% was meningitis. The most frequent SBI was pneumonia (n = 69, 11.6%) followed by urinary tract infection (UTI; n = 37, 6.2%). Predominant pathogens (excluding contaminants) were Escherichia coli (51.2% of the UTI cases), group B Streptococcus (62.5% of meningitis cases), and Staphylococcus aureus (61.5% of bacteremia cases). Seven infants presented with bacterial pneumonia due to Staphylococcus aureus with Panton–Valentine leucocidin (PVL) exotoxin production. Ill-appearing infants, clinical signs of SBI and complex chronic condition were associated with a risk of SBI (respective odds ratio [OR]: 4.6, 95% confidence interval [CI]: 3–6.9; OR: 4.2, 95% CI: 2.8–6.4; and OR: 3.2, 95% CI: 1.2–8.5). The median age for SBI was 42 days (5–90). Fever without source (FWS) occurred more often in infants under 21 days of age (48.5% vs. 31.3% in older infants, p < 0.001). The median duration of fever at home was 24 h (6–96). Concerning management, in infants aged under 21 days, there were more lumbar punctures (58.3% vs. 23% in older infants, p < 0.001) and more frequent initiation of empiric antibiotics (62.6% vs. 42.7%, p < 0.001). Length of stay was also longer in this age range (5 days vs. 3 days, p = 0.037).

Delay in medical consultation in the case of fever, the risk of SBI regardless of age, and unusual epidemiology with many IBI due to Staphylococcus aureus with PVL exotoxin production are specific characteristics observed in our study. Knowledge of the current epidemiology of SBI in Mayotte would be useful for setting up a risk-stratified protocol in this population in the future.