1001. Evaluation of the Clinical Efficacy and Safety of Oral Antibiotic Therapy for Streptococcus spp. Bloodstream Infections

The efficacy and safety of a shortened duration of antimicrobial therapy for group A Streptococcus bacteremia

OBJECTIVES

To determine if shorter courses of antibiotic therapy for group A Streptococcus (GAS) bacteremia are associated with excess mortality.

METHODS

In this retrospective study of consecutive cases of GAS bacteremia in tropical Australia, the duration of antibiotic therapy was correlated with 90-day all-cause mortality.

RESULTS

There were 286 episodes of GAS bacteremia; the patients' median (interquartile range) age was 60 (48-71) years and 169/286 (59.1%) patients identified as an Indigenous Australian. There were 227/286 (79.4%) patients with a significant comorbidity. The all-cause 90-day mortality was 16/286 (5.6%); however, 12/16 (81.3%) patients died while still receiving their initial course of antibiotics and only 7/16 (43.8%) deaths were directly attributable to the GAS infection. After excluding patients who died while taking their initial course of antibiotics and those in whom the duration of therapy was uncertain, there was no difference in 90-day mortality between patients receiving ≤5 days of intravenous antibiotics and those receiving longer courses (1/137 [0.7%] vs 3/107 [2.8%], P-value = 0.32) nor in patients receiving ≤10 days of total therapy and those receiving longer courses (1/67 [1.5%] vs 3/178 [1.7%], P-value = 1.0).

CONCLUSION

Even among patients with significant comorbidity, shorter antibiotic courses for GAS bacteremia are not associated with excess mortality.

A retrospective analysis of intravenous versus oral antibiotic step-down therapy for the treatment of uncomplicated Streptococcal bloodstream infections

Evidence supporting intravenous to oral (IV-to-PO) antibiotic de-escalation for uncomplicated Streptococcal bloodstream infections (BSIs) are limited. The objective of this study was to compare clinical outcomes of patients treated with IV-only versus IV-to-PO antibiotic therapy for uncomplicated Streptococcal BSIs. This was a single center, retrospective study of patients 18 years and older who received treatment for uncomplicated Streptococcal BSIs from January 2017 to December 2019. Patients were excluded if they had a polymicrobial BSI, endocarditis, osteomyelitis, septic arthritis, or received antibiotic therapy for longer than 14 days. The primary outcome was clinical failure, defined as persistent bacteremia, recurrence of bacteremia, or mortality at 30 days. Secondary outcomes included length of hospital stay, all-cause readmissions, development of C.difficile infection, and adverse antibiotic reactions. There were 98 patients who met the inclusion criteria; 51 patients in the IV-to-PO therapy group and 47 patients who received IV-only antibiotics. Streptococcus pneumonia and beta-hemolytic Streptococci were the most common pathogens. Patients received an average of 4.4 days of IV antibiotics before being stepped down to an oral agent. Hospital length of stay (6.3 vs. 12.6 days, p < 0.001) and total antibiotic duration of therapy (11.8 vs. 13.9 days, p = 0.002) were significantly shorter in patients receiving IV-to-PO therapy. There were no clinical failures observed in patients who received IV-to-PO antibiotic therapy. IV-to-oral step down therapy for uncomplicated Streptococcal BSIs was not associated with worse clinical outcomes compared to patients receiving IV-only antibiotic therapy. This article is protected by copyright. All rights reserved.

Fluoroquinolone versus Beta-Lactam Oral Step-Down Therapy for Uncomplicated Streptococcal Bloodstream Infections

Fluoroquinolones (FQs) are often preferred as oral step-down therapy for bloodstream infections (BSIs) due to favorable pharmacokinetic parameters; however, they are also associated with serious adverse events. The objective of this study was to compare clinical outcomes for patients who received an oral FQ versus an oral beta-lactam (BL) as step-down therapy for uncomplicated streptococcal BSIs. This multicenter, retrospective cohort study analyzed adult patients who completed therapy with an oral FQ or BL with at least one blood culture positive for a Streptococcus species from 1 January 2014 to 30 June 2019. The primary outcome was clinical success, defined as the lack of all-cause mortality, recurrent BSI with the same organism, and infection-related readmission at 90 days. A multivariable logistic regression model for predictors of clinical failure was conducted. A total of 220 patients were included, with 87 (40%) receiving an FQ and 133 (60%) receiving a BL. Step-down therapy with an oral BL was noninferior to an oral FQ (93.2% versus 92.0%; mean difference, 1.2%; 90% confidence interval [CI], -5.2 to 7.8). No differences were seen in 90-day mortality, 90-day recurrent BSI, 90-day infection-related readmission, or 90-day incidence of Clostridioides difficile-associated diarrhea. Predictors of clinical failure included oral step-down transition before day 3 (odds ratio [OR] = 5.18; 95% CI, 1.21, 22.16) and low-dose oral step-down therapy (OR = 2.74; 95% CI, 0.95, 7.90). Our results suggest that oral step-down therapy for uncomplicated streptococcal BSI with a BL is noninferior to an FQ.

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.