Intravenous to oral transition of antibiotics for gram-negative bloodstream infection at a University hospital in Thailand: Clinical outcomes and predictors of treatment failure.

Background: Limited studies evaluate the outcome of intravenous antibiotics to oral transition in Gram-negative bloodstream infection (GN-BSI), particularly GN-BSI originating outside the urinary tract. This study aimed to evaluate treatment success in patients with GN-BSI treated with either intravenous therapy or intravenous to oral transition and to identify factors associated with treatment failure in those undergoing intravenous to oral transition.

Methods: A retrospective cohort study was conducted at King Chulalongkorn Memorial Hospital, Thailand. Patients were included if they were ≥18 years of age, hospitalized in general medical wards with GN-BSI between August 1, 2015, to July 31, 2020, received intravenous antibiotic agents and had a functioning gastrointestinal tract.

Results: Of 955 patients, 545 (57.1%) were in the intravenous to oral transition group. The urinary tract was the most common source of infection (38.8%). Ciprofloxacin was the most prescribed oral antibiotic (53%). Treatment success occurred in 94.3% in the intravenous antibiotic to oral transition group. There was no significant difference in treatment success between the two groups (P = 0.790) with a concordant result after using propensity score matching (P = 0.223). Independent predictors of treatment failure in the intravenous to oral transition group included metastatic solid cancer (aOR = 4.355), HIV infection with CD4 < 200 cells/mm3 (aOR = 8.452), qSOFA score ≥ 2 (aOR = 2.545), multidrug-resistant infection (aOR = 2.849), and respiratory tract infection (aOR = 8.447). Hospital length of stay in the intravenous to oral transition group was shorter than in the intravenous group (P < 0.001).

Conclusions: Intravenous to oral transition may be a practical approach in GN-BSI. Patients with Gram-negative bacteremia who have HIV infection with CD4 < 200 cells/mm3, multidrug-resistant infections, and respiratory tract sources of infection may not be ideal candidates for this approach. Future research is needed from a randomized controlled trial.