P-812. Not Little Adults: Key Differences in Antimicrobial Resistance in Australian Bloodstream Isolates between Children and Adults, 2020-2021

Abstract Background The incidence, risks and organisms causing bloodstream infections (BSI) differ between children and adults due to distinct comorbidities, procedures and antibiotic exposures. Age-specific data are required to inform targeted interventions, empiric treatment and guideline development. We aimed to compare the incidence, risk factors and resistance patterns of bacteria causing BSI in children and adults (2020-21). Methods The Australian Group on Antimicrobial Resistance (AGAR) is a national hospital-based BSI surveillance program reporting on Staphylococcus aureus, Enterococcus spp. and key gram-negative pathogens. Results Data from 25,958 isolates were assessed (children: 1,679; adults: 24,279). The most common organisms in children and adults were Escherichia coli (20.9 vs 39.1%) and S. aureus (36.2 vs 20.9%). E. faecalis and non-typhoidal Salmonella spp. were more frequent in children (7.3% and 4.4% of surveyed organisms in children vs 5.1% and 0.5% in adults). BSI were more often community onset (69.0% children; 76.4% adults). 30-day mortality was significantly lower in children (3.3% vs 9.8%). Enterobacterales resistance was more common in children: e.g. to gentamicin/tobramycin (11.6% of child isolates; 8.5%, adult isolates; rate ratio [RR]: 1.4 [95%CI: 1.1-1.7]) and piperacillin-tazobactam resistance (11.2%; 8.6%; RR: 1.3 [1.0-1.6]). However, there was no difference observed in Enterobacterales resistance to cephalosporins, ciprofloxacin, meropenem or multi-drug resistance status. AMR prevalence in Pseudomonas and Acinetobacter spp isolates were also similar between children and adults. Methicillin-resistant S. aureus isolates were less common in children (13.2 vs 17.7%; RR: 0.7 [0.6-0.9]). Rates of clindamycin and cotrimoxazole resistance in S. aureus were similar to adults. Children had a lower proportion of E. faecium infections (24.1 vs 39.8%) and the rate of vancomycin-resistant E. faecium in children was half that in adults (19.5 vs 37.2%; RR; 0.5, [0.2-1.0]). Conclusion Analysis of national AMR data identifies unique trends in children. Ongoing clinical surveillance, targeted prevention, antimicrobial stewardship strategies and research to evaluate AMR drivers in children are required. Disclosures All Authors: No reported disclosures