Pseudomonas aeruginosa bloodstream infections in children in Queensland, Australia, 2000–2019

Aim:
To investigate the incidence, risk factors and outcomes of Pseudomonas aeruginosa bloodstream infections (P-BSI) in Queensland children aged 0–18 years.

Methods:
A retrospective data-linkage study was conducted of P-BSI identified by Pathology Queensland laboratories from resident Queensland children admitted to publicly-funded Queensland Hospitals between 2000 and 2019. We estimated age-standardised incidence of P-BSI and case fatality ratios (48 h, 7-, 30- and 90-day all-cause mortality from the date of the blood culture collection). Data on underlying co-morbidities related to the episode of P-BSI were collected from statewide databases.

Results:
Overall, 297 episodes of P-BSI were identified in 265 children, with an overall incidence of 1.14 infections/100 000 child-years. The median age of children with P-BSI was 3.7 years [interquartile range 1.2–10.7 years]. Almost 90% (n = 266/297) of infections were healthcare-associated. There were 36 (36 episodes) neonates (31 preterm <37 weeks gestation), of whom 12 (33.3%) and 15 (41.7%) neonates died within 48 h and 7 days of the P-BSI, respectively. The remaining 229 (261 episodes) children were aged 1 month to 18 years, and 234/261 (89.7%) episodes were associated with underlying co-morbidities, especially haematological malignancies. Eleven, 15 and 24 of the 229 children beyond the neonatal age group died within 48 h (4.8%), 7 days (6.6%) and 30 days (10.5%), respectively of the index blood culture. Neonates, healthcare-associated hospital onset infections, cardiovascular co-morbidity, and multi-drug resistance were significantly associated with early mortality.

Conclusions:
P-BSI occurs predominantly in vulnerable, hospitalised children with underlying comorbidities, especially in preterm neonates and those with haematological malignancies, and is associated with substantial mortality.