The Incidence of Serious/Invasive Bacterial Diseases in Infants 90 Days Old or Younger at an Emergency Hospital in Japan

Saeka Yoshitake; Yoshiki Kusama; Kenta Ito; Hiroyuki Kuroda; Muneyasu Yamaji; Kento Ishitani; Yusuke Ito; Katsunori Kamimura; Toshiro Maihara

doi:10.7759/cureus.36494

The Incidence of Serious/Invasive Bacterial Diseases in Infants 90 Days Old or Younger at an Emergency Hospital in Japan

Cureus. 2023 Mar 21;15(3):e36494. doi: 10.7759/cureus.36494. eCollection 2023 Mar.

Authors

Saeka Yoshitake¹, Yoshiki Kusama², Kenta Ito³, Hiroyuki Kuroda², Muneyasu Yamaji¹, Kento Ishitani¹, Yusuke Ito⁴, Katsunori Kamimura¹, Toshiro Maihara⁵

Affiliations

¹ Department of Pediatrics, Hyogo Prefectural Amagasaki Medical Center, Amagasaki, JPN.
² Department of Pediatrics, Hyogo Prefectural Amagasaki General Medical Center, Amagasaki, JPN.
³ Department of General Pediatrics, Aichi Children's Health and Medicine Hospital, Obu, JPN.
⁴ Department of Pediatric Infectious Diseases, Hyogo Prefectural Amagasaki Medical Center, Amagasaki, JPN.
⁵ Department pf Pediatrics, Hyogo Prefectural Amagasaki General Medical Center, Amagasaki, JPN.

Abstract

Background The incidence of severe bacterial infections (SBIs) in infants aged ≤90 days is thought to have decreased because of widespread vaccination programs. However, relevant epidemiological data in Japan are scarce. Materials and methods This observational, single-center study investigated the epidemiology of fever in infants aged ≤90 days. SBI was defined as the presence of meningitis, urinary tract infections (UTIs), or bacteremia. Invasive bacterial infection (IBI) was defined as the presence of meningitis, bacteremic UTI, or bacteremia. We determined the incidence of UTIs, bacteremia, meningitis, SBIs, and IBIs in the following three age groups: 0-28, 29-60, and 61-90 days. We subsequently calculated the relative incidence for the groups aged 29-60 and 61-90 days, using the group aged 0-28 days as the reference group. Results Herein, 58, 124, and 166 infants were included in the 0-28 days, 29-60 days, and 61-90 days age groups, respectively. Of the total number of patients, 15.5%, 8.9%, and 16.9% in the 0-28 days, 29-60 days, and 61-90 days age groups, respectively, were diagnosed with SBI. The relative incidences were 1 for the 0-28 days group (reference group), 0.67 for the 29-60 days group (95% confidence interval [CI], 0.39-1.15), and 1.08 for the 61-90 days group (95% CI, 0.58-2.00). Of the total number of patients, 10.3%, 3.2%, and 0.6% in the 0-28 days, 29-60 days, and 61-90 days age groups, respectively, were diagnosed with IBI. Relative incidences were 1 (reference group), 0.50 (95% CI, 0.29-0.88), and 0.28 (95% CI, 0.19-0.41) for the 0-28 days, 29-60 days, and 61-90 days age groups, respectively. All cases of IBI were caused by Group B streptococcus (GBS), except for two cases of bacteremia, which were caused by Haemophilus influenzae. Conclusion The incidence of SBI was similar in the 0-28 days and 61-90 days age groups. However, the incidence of IBI decreased with increasing age. The incidence of UTIs was highest in the 61-90 days age group, and that of meningitis and bacteremia decreased with increasing age.

Keywords: incidience; infantile fever; invasive bacterial infection; lumbar puncture; severe bacterial infection.