Transition from intravenous to oral antimicrobial therapy in patients with uncomplicated and complicated bloodstream infections

Background: The role of oral antimicrobial agents in the management of bloodstream infections (BSI) is currently evolving.

Objectives: This narrative review summarizes and appraises clinical studies that examined transition from intravenous to oral antimicrobials or compared effectiveness of various oral agents for definitive therapy of uncomplicated and complicated BSI in adults.

Sources: Relevant English-language studies from MEDLINE (since inception) and presented abstracts at international scientific meetings (since 2017).

Content: Emerging data suggest potential utility of oral switch strategy, particularly to oxazolidinones, as an alternative to standard intravenous therapy in low-risk patients with uncomplicated Staphylococcus aureus BSI. Moreover, results of recent randomized clinical trials are promising that combination oral regimens may play a role in antimicrobial management of complicated Gram-positive BSI, including infective endocarditis, septic arthritis and osteomyelitis. Whereas oral fluoroquinolones have been used successfully for decades in both uncomplicated and complicated Gram-negative BSI, recent studies suggest that trimethoprim-sulfamethoxazole and aminopenicillins represent alternative oral options in uncomplicated Enterobacteriaceae BSI. Oral azoles have been used for definitive therapy of Candida species BSI and are currently recommended by the international management guidelines.

Implications: Recent studies demonstrate that early transition from intravenous to oral therapy is a feasible and effective strategy in most patients with BSI due to Gram-negative bacteria, obligate anaerobic bacteria and Candida species. Oral antimicrobial combinations may be considered in select patients with complicated Gram-positive BSI after 10-14 days of intravenous therapy. Future studies will determine the role of oral agents for switch therapy in uncomplicated Gram-positive BSI.