1430. The Hidden Costs of Vancomycin Use During the Treatment of Staphylococcus aureus Bacteremia Concurrent with Acute Hematogenous Osteomyelitis

BACKGROUND: Current guidelines recommend the use of parenteral vancomycin for children with acute hematogenous osteomyelitis and concurrent Staphylococcus aureus bacteremia (SAB) due to Methicillin-Resistant Staphylococcus aureus (MRSA), despite vancomycin’s slow bactericidal activity. This study explores the hidden costs of this approach. METHODS: Children with AHO and concurrent SAB, treated from 2009 to 2018, who had received vancomycin at some point during their treatment course were studied. Data collected included antibiotic susceptibilities; duration of bacteremia, blood culture results, duration of vancomycin; number of dose/interval changes; vancomycin trough and creatinine levels; rate of achieving target trough; use of other nephrotoxic agents; occurrence of acute kidney injury (AKI); and length of stay. RESULTS: 130 children diagnosed with AHO and concurrent SAB received vancomycin. Isolates were CR MSSA (3 or 2.3%), CR MRSA (5 or 3.8%), CS MSSA (35 or 26.9%), and CS MRSA (87 or 66.9%). Mean LOS was 14.6 days. 1,312 blood cultures were obtained (503 positive cultures and 809 negative cultures). Bacteremia persisted an average of 3.6 days. Target trough level (15–20 µg/mL) was achieved in 65 children (50%) within an average of 3.4 days of initial dosing. Attempts to reach therapeutic levels were abandoned in 32 children (24.6%) as MSSA was isolated before the trough. There were 319 vancomycin dose and/or interval changes, 1,192 serum creatinine levels, and 689 vancomycin trough levels obtained. Fourteen children (10.8%) experienced AKI. Additional nephrotoxicity exposure included: NSAIDs (127), IV contrast (100), loop diuretics (37), and aminoglycosides (11). CONCLUSION: This study exposes and quantifies a substantial amount of resources devoted to dosing adjustments and serum level monitoring for vancomycin use in children with AHO and concurrent SAB. The cost differential in comparison to that of newer antibiotic alternatives is undermined by the effort to attain therapeutic target levels, resolve bacteremia, and address episodic AKI. If vancomycin is utilized, a deliberate approach should be taken to minimize risk of toxicity, including AUC/MIC ratio calculation, as opposed to therapeutic level monitoring, and avoid the concurrent use of other nephrotoxic agents. [Image: see text] DISCLOSURES: All authors: No reported disclosures.