Vol.74 No.5 September 2026

Is early oral switch after short-term intravenous therapy feasible in antimicrobial treatment of native vertebral osteomyelitis?— A retrospective analysis of 65 patients —

Taku Ozawa¹⁾, Mutsunobu Yoshioka¹⁾, Satoshi Ishizu¹⁾ and Osamu Yohena¹⁾

¹⁾Department of Pharmacy, Takarazuka City Hospital, 4-5-1 Kohama, Takarazuka, Hyogo, Japan

Abstract

Prolonged antimicrobial therapy is often required for native vertebral osteomyelitis (NVO); however, the feasibility of early transition from intravenous to oral antibiotics has recently gained attention. We evaluated the safety and effectiveness of early oral step-down therapy within 14 days of the start of therapy under universal intervention by the hospital antimicrobial stewardship team.
We retrospectively analyzed the data of 65 patients who were diagnosed as having NVO and received antimicrobial therapy at our institution between 2015 and 2023. Patients who were switched to oral antibiotics within 14 days of the start of treatment were classified as the Early switch group (n=35), while those who received intravenous therapy for ≥15 days were classified as the Non-early switch group (n=30). The primary outcome was treatment failure, defined as death during treatment, recurrence within one year after treatment completion, or clinical deterioration requiring reinitiation of intravenous therapy after oral switch. Secondary outcomes included the serum C-reactive protein levels at weeks 1 and 2, length of hospital stay, cost of antimicrobial therapy, and adverse events. There was no significant difference in the mean age, sex ratio, frequency of comorbidities, infection site distribution, baseline inflammatory marker levels, frequency of neurological symptoms/sepsis/surgical intervention, or prevalence of abscess. There was also no significant difference in the treatment failure rate between the Early switch group and Non-early switch group (11.4% vs. 10.0%). Although the total duration of antimicrobial therapy did not differ significantly between the two groups, the hospital stay was significantly shorter and the antimicrobial therapy cost significantly lower in the Early switch group. The incidence of adverse events was comparable between the two groups.

Key word

antimicrobial stewardship, vertebral osteomyelitis, appropriate use, oral administration

Received

February 6, 2026

Accepted

May 7, 2026

Jpn. J. Chemother. 74 (5): 538-546, 2026