Antimicrobial Resistance in Enterobacterales, Acinetobacter spp. and Pseudomonas aeruginosa Isolates From Bloodstream Infections in Australian Children, 2013-2021.

BACKGROUND

Gram-negative bloodstream infections are associated with significant morbidity and mortality in children. Increasing antimicrobial resistance (AMR) is reported globally, yet efforts to track pediatric AMR at a national level over time are lacking.

METHODS

The Australian Group on Antimicrobial Resistance (AGAR) surveillance program captures clinical and microbiological data of isolates detected in blood cultures across Australia. EUCAST 2022 was used for MIC interpretation and the AMR package in R for data analysis.

RESULTS

Over a 9-year period, there were 3145 bloodstream infections with 3266 gram-negative isolates reported in hospitalized children aged <18 years; 21.0% were from neonates. The median length of stay was 9 days, and 30-day all-cause mortality was 5.2%. A greater odds of death was observed in those with a multi-drug resistant organism (aOR: 2.1, 95% CI: 1.3, 3.3, p: 0.001). Escherichia coli (44.5%) and Klebsiella pneumoniae complex (12.6%) were the two most frequently reported organisms. Overall resistance in Enterobacterales to gentamicin/tobramycin was 11.6%, to ceftazidime/ceftriaxone was 12.9%, and 13.2% to ciprofloxacin. Resistance increased over time. Of the 201 Pseudomonas aeruginosa isolates reported, 19.7% were resistant to piperacillin-tazobactam, 13.1% resistant to cefepime/ceftazidime, and 9.8% to ciprofloxacin. Of 108 Acinetobacter spp. isolates, one was resistant to meropenem, and two were resistant to ciprofloxacin. Resistance did not increase over time.

CONCLUSIONS

AMR in gram-negative organisms causing bloodstream infections in Australian children is increasing, which should be considered when updating guidelines and empiric treatment regimens. Ongoing pediatric-specific national surveillance with pediatric reporting must remain a priority to strengthen antimicrobial stewardship and infection control programs.