The benefits and safety of oral sequential antibiotic therapy in non-complicated and complicated Staphylococcus aureus bacteremia

Transitioning to oral therapy compared to IV in Staphylococcus aureus bloodstream infections: a systematic review and meta-analysis

Background and Objective

Staphylococcus aureus bloodstream infections pose a significant threat to public health and necessitate substantial healthcare resources. The optimal antimicrobial therapy for these infections remains a subject of debate. This systematic review and meta-analysis evaluated the efficacy and safety of early transition to oral antimicrobial therapy compared with continued intravenous (IV) therapy in patients with MRSA and MSSA bloodstream infections.

Method

A PRISMA-guided systematic review and meta-analysis compared the early transition from intravenous to oral antibiotics with continued intravenous therapy in patients with S. aureus infections, utilizing relevant studies from the PubMed, Embase, Scopus, and Web of Science databases from August 2003 to June 2024.

Results

This meta-analysis of 11 studies (N = 54-220, primarily male, age: mid-30s to early 70s) revealed a 71.6% higher risk of all-cause mortality for patients transitioned to early oral therapy than for those who continued IV therapy (RR: 1.716; 95% CI: 1.039-2.836; P = 0.035; I2 = 44%). Treatment failure, rehospitalization rates, adverse events, and hospital stay lengths did not differ significantly between groups.

Conclusion

Early oral antimicrobial therapy for S. aureus bloodstream infections significantly reduces mortality compared to prolonged intravenous treatment, without increasing the incidence of adverse events or the risk of rehospitalization, suggesting its safety and efficacy as an alternative therapeutic approach; however, further randomized controlled trials are necessary to corroborate these findings.

Early Oral Antibiotic Switch in Staphylococcus aureus Bacteraemia: The Staphylococcus aureus Network Adaptive Platform (SNAP) Trial Early Oral Switch Protocol

BACKGROUND

Staphylococcus aureus bloodstream infection (bacteremia) is traditionally treated with at least 2 weeks of intravenous (IV) antibiotics in adults, 3-7 days in children, and often longer for those with complicated disease. The current practice of treating S. aureus bacteremia (SAB) with prolonged IV antibiotics (rather than oral antibiotics) is based on historical observational research and expert opinion. Prolonged IV antibiotic therapy has significant disadvantages for patients and healthcare systems, and there is growing interest in whether a switch to oral antibiotics following an initial period of IV therapy is a safe alternative for clinically stable patients.

PROTOCOL

The early oral switch (EOS) domain of the S. aureus Network Adaptive Platform (SNAP) trial will assess early switch to oral antibiotics compared with continued IV treatment in clinically stable patients with SAB. The primary endpoint is 90-day all-cause mortality. Hospitalised SAB patients are assessed at platform day 7 ±2 (uncomplicated SAB) and day 14 ±2 (complicated SAB) to determine their eligibility for randomization to EOS (intervention) or continued IV treatment (current standard of care).

DISCUSSION

Recruitment is occurring in the EOS domain of the SNAP trial. As of August 2023, 21% of all SNAP participants had been randomized to the EOS domain, a total of 264 participants across 77 centers, with an aim to recruit at least 1000 participants. We describe challenges and facilitators to enrolment in this domain to aid those planning similar trials.

Efficacy and safety of an early oral switch in low-risk Staphylococcus aureus bloodstream infection (SABATO): an international, open-label, parallel-group, randomised, controlled, non-inferiority trial

BACKGROUND

Staphylococcus aureus bloodstream infection is treated with at least 14 days of intravenous antimicrobials. We assessed the efficacy and safety of an early switch to oral therapy in patients at low risk for complications related to S aureus bloodstream infection.

METHODS

In this international, open-label, randomised, controlled, non-inferiority trial done in 31 tertiary care hospitals in Germany, France, the Netherlands, and Spain, adult patients with low-risk S aureus bloodstream infection were randomly assigned after 5-7 days of intravenous antimicrobial therapy to oral antimicrobial therapy or to continue intravenous standard therapy. Randomisation was done via a central web-based system, using permuted blocks of varying length, and stratified by study centre. The main exclusion criteria were signs and symptoms of complicated S aureus bloodstream infection, non-removable foreign devices, and severe comorbidity. The composite primary endpoint was the occurrence of any complication related to S aureus bloodstream infection (relapsing S aureus bloodstream infection, deep-seated infection, and mortality attributable to infection) within 90 days, assessed in the intention-to-treat population by clinical assessors who were masked to treatment assignment. Adverse events were assessed in all participants who received at least one dose of study medication (safety population). Due to slow recruitment, the scientific advisory committee decided on Jan 15, 2018, to stop the trial after 215 participants were randomly assigned (planned sample size was 430 participants) and to convert the planned interim analysis into the final analysis. The decision was taken without knowledge of outcome data, at a time when 126 participants were enrolled. The new sample size accommodated a non-inferiority margin of 10%; to claim non-inferiority, the upper bound of the 95% CI for the treatment difference (stratified by centre) had to be below 10 percentage points. The trial is closed to recruitment and is registered with ClinicalTrials.gov (NCT01792804), the German Clinical trials register (DRKS00004741), and EudraCT (2013-000577-77).

FINDINGS

Of 5063 patients with S aureus bloodstream infection assessed for eligibility, 213 were randomly assigned to switch to oral therapy (n=108) or to continue intravenous therapy (n=105). Mean age was 63·5 (SD 17·2) years and 148 (69%) participants were male and 65 (31%) were female. In the oral switch group, 14 (13%) participants met the primary endpoint versus 13 (12%) in the intravenous group, with a treatment difference of 0·7 percentage points (95% CI -7·8 to 9·1; p=0·013). In the oral switch group, 36 (34%) of 107 participants in the safety population had at least one serious adverse event compared with 27 (26%) of 103 participants in the intravenous group (p=0·29).

INTERPRETATION

Oral switch antimicrobial therapy was non-inferior to intravenous standard therapy in participants with low-risk S aureus bloodstream infection. However, it is necessary to carefully assess patients for signs and symptoms of complicated S aureus bloodstream infection at the time of presentation and thereafter before considering early oral switch therapy.

FUNDING

Deutsche Forschungsgemeinschaft.

TRANSLATIONS

For the German, Spanish, French and Dutch translations of the abstract see Supplementary Materials section.

Oral Antibiotics for Bacteremia and Infective Endocarditis: Current Evidence and Future Perspectives

Bacteremia and endocarditis are two clinical syndromes that, for decades, were managed exclusively with parenteral antimicrobials, irrespective of a given patient's clinical condition, causative pathogen, or its antibiotic susceptibility profile. This clinical approach, however, was based on low-quality data and outdated expert opinions. When a patient's condition has improved, gastrointestinal absorption is not compromised, and an oral antibiotic regimen reaching adequate serum concentrations is available, a switch to oral antibacterials can be applied. Although available evidence has reduced the timing of the oral switch in bacteremia to three days/until clinical improvement, there are only scarce data regarding less than 10-day intravenous antibiotic therapy in endocarditis. Many standard or studied oral antimicrobial dosages are smaller than the approved doses for parenteral administration, which is a risk factor for treatment failure; in addition, the gastrointestinal barrier may affect drug bioavailability, especially when the causative pathogen has a minimum inhibitory concentration that is close to the susceptibility breakpoint. A considerable number of patients infected by such near-breakpoint strains may not be potential candidates for oral step-down therapy to non-highly bioavailable antibiotics like beta-lactams; different breakpoints should be determined for this setting. This review will focus on summarizing findings about pathogen-specific tailoring of oral step-down therapy for bacteremia and endocarditis, but will also present laboratory and clinical data about antibiotics such as beta-lactams, linezolid, and fosfomycin that should be studied more in order to elucidate their role and optimal dosage in this context.

Choosing patients over placebos: oral transitional therapy vs. IV-only therapy for bacteraemia and infective endocarditis

BACKGROUND

The belief that antibiotics must be administered intravenously (IV) to treat bacteraemia and endocarditis has its origins 70 years ago and has engrained itself in the psyche of the medical community and the public at large. This has led to hesitancy in adopting evidence-based strategies utilizing oral transitional therapy for the treatment of these infections. We aim to reframe the narrative around this debate, focusing on patient safety over vestigial psychology.

OBJECTIVES

This narrative review summarizes the current state of the literature regarding the use of oral transitional therapy for the treatment of bacteraemia and infective endocarditis, focusing on studies comparing it to the traditional, IV-only approach.

SOURCES

Relevant studies and abstracts from PubMed reviewed in April 2023.

CONTENT

Treating bacteraemia with oral transitional therapy has been studied in 9 randomized controlled trials (RCTs), totalling 625 patients, as well as numerous large, retrospective cohorts, including 3 published in the last 5 years alone, totalling 4763 patients. We identified 3 large, retrospective cohort studies; one quasi-experimental, pre-post study, and 3 RCTs of patients with endocarditis, totalling 748 patients in the retrospective cohorts and 815 patients in prospective, controlled studies. In all these studies, no worse outcomes were observed in the oral transitional therapy arm as compared with IV-only therapy. The main difference has consistently been longer durations of inpatient hospitalization and increased risk of catheter-related adverse events like venous thrombosis and line-associated blood stream infections in the IV-only groups.

IMPLICATIONS

There are ample data showing that choosing oral therapy reduces hospital stay and has fewer adverse events for patients than IV-only therapy, all with similar or better outcomes. In selected patients, choosing IV-only therapy may serve more as an anxiolytic "placebo" for the patient and provider rather than a necessity for treating the actual infection.

Early switching from intravenous to oral antibiotic therapy in bone and joint infections associated with methicillin-susceptible Staphylococcus aureus bacteremia

OBJECTIVES

We aimed to evaluate the clinical outcomes of patients with bone and joint infection (BJI) associated with methicillin-susceptible Staphylococcus aureus bacteremia (MSSAB) treated with early oral switch to oral antibiotics (before day 14) versus later or no switch.

PATIENTS AND METHODS

We included all cases reported between January 2016 and December 2021 in the University Hospital of Reims.

RESULTS

Among 79 patients with BJI associated with MSSAB, 50.6% had an early switch to oral antibiotics, with median duration of intravenous antibiotics of 9 (IQR 6-11) days. The overall cure rate was 81% with follow-up of 6 months, and was 85.7% after excluding the 9 patients whose death was not related to BJI infection. Failure to control BJI did not differ between the two groups.

CONCLUSION

An early (before day 14) switch to oral antibiotics may be a safe therapeutic option in BJI associated with MSSAB.

Carbapenem alternatives for treatment of bloodstream infections due to AmpC producing enterobacterales

INTRODUCTION

Carbapenems (CR) have traditionally been the first line treatment for bacteremia caused by AmpC-producing Enterobacterales. However, CR have a high ecological impact, and carbapenem-resistant strains continue rising. Thus, other treatment alternatives like Piperacillin-Tazobactam (P-T) or Cefepime (CEF) and oral sequential therapy (OST) are being evaluated.

METHODS

We conducted a retrospective, single-centre observational study. All adult patients with AmpC-producing Enterobacterales bacteremia were included. The primary endpoint was clinical success defined as a composite of clinical cure, 14-day survival, and no adverse events. We evaluated the evolution of patients in whom OST was performed.

RESULTS

Seventy-seven patients were included, 22 patients in the CR group and 55 in the P-T/CEF group (37 patients received CEF and 18 P-T). The mean age of the patients was higher in the P-T/CEF group (71 years in CR group vs. 76 years in P-T/CEF group, p = 0.053). In the multivariate analysis, age ≥ 70 years (OR 0.08, 95% CI [0.007-0.966], p = 0.047) and a Charlson index ≥ 3 (OR 0.16, 95% CI [0.026-0.984], p = 0.048), were associated with a lower clinical success. Treatment with P-T/CEF was associated with higher clinical success (OR 7.75, 95% CI [1.273-47.223], p = 0.026). OST was performed in 47% of patients. This was related with a shorter in-hospital stay (OST 14 days [7-22] vs. non-OST 18 days [13-38], p = 0.005) without difference in recurrence (OST 3% vs. non-OST 5%, p = 0.999).

CONCLUSIONS

Targeted treatment with P-T/CEF and OST could be safe and effective treatments for patients with AmpC-producing Enterobacterales bacteremia.

Sequential oral antibiotic in uncomplicated Staphylococcus aureus bacteraemia: a propensity-matched cohort analysis

OBJECTIVES

We aimed to analyse the efficacy and safety of oral sequential therapy (OST) in uncomplicated Staphylococcus aureus bacteraemia (SAB).

METHODS

Single-centre observational cohort at a tertiary hospital in Spain, including all patients with the first SAB episode from January 2015 to December 2020. We excluded patients with complicated SAB and those who died during the first week. Patients were classified into the OST group (patients who received oral therapy after initial intravenous antibiotic therapy [IVT]), and IVT group (patients who received exclusively IVT). We performed a propensity-score matching to balance baseline differences. The primary composite endpoint was 90-day mortality or microbiological failure. Secondary endpoints included 90-day SAB relapse.

RESULTS

Out of 407 SAB first episodes, 230 (56.5%) were included. Of these, 112 (n = 48.7%) received OST and 118 (51.3%) IVT exclusively. Transition to oral therapy was performed after 7 days (interquartile range, 4-11). The primary endpoint occurred in 10.7% (11/112) in OST vs. 30.5% (36/118) in IVT (p < 0.001). SAB relapses occurred in 3.6% (4/112) vs. 1.7% (2/118) (p 0.436). None of the deaths in OST were related to SAB or its complications. After propensity-score matching, the primary endpoint was not more frequent in the OST group (relative risk, 0.42; 95% CI, 0.22-0.79). Ninety-day relapses occurred similarly in both groups (relative risk, 1.35; 95% CI, 0.75-2.39).

DISCUSSION

After an initial intravenous antibiotic, patients with uncomplicated SAB can safely be switched to oral antibiotics without apparent adverse outcomes. This strategy could save costs and complications of prolonged hospital stays. Prospective randomized studies are needed.

Redefining Staphylococcus aureus bacteremia: A structured approach guiding diagnostic and therapeutic management

The current duration of therapy in patients with Staphylococcus aureus bacteremia (SAB) is based on differentiating complicated from uncomplicated disease. While this approach allows clinicians and investigators to group SAB patients into broadly similar clinical categories, it fails to account for the intrinsic heterogeneity of SAB. This is due in part to the fact that risk factors for metastatic infection and confirmed metastatic infection are considered as equivalent in most scoring systems. In this viewpoint, we propose a two-step system of categorizing patients with SAB. Initially, patients with SAB would be categorized as 'high risk' or 'low risk' for metastatic infection based upon an initial set of diagnostic procedures. In the second step, patients identified as 'high-risk' would undergo additional diagnostic evaluation. The results of this stepwise diagnostic evaluation would define a 'final clinical diagnosis' to inform an individualized final treatment plan.

An evaluation of risk factors for readmission in patients receiving outpatient parenteral antimicrobial therapy

Background

Outpatient parenteral antimicrobial therapy (OPAT), when required, is beneficial to patients and healthcare systems by reducing hospital length-of-stay, providing cost savings, and improving patient satisfaction.

Objectives

The purpose of this study is to determine readmission rates and associated risk factors in patients receiving OPAT at home.

Methods

This retrospective study included hospitalized patients 15 years and older who were discharged on intravenous antimicrobial therapy via OPAT at home between January 2018 and December 2019. Patients receiving antimicrobials at a skilled nursing facility, long-term acute care, or dialysis center, and those who began OPAT at home directly from the outpatient setting were excluded. The primary outcome of this study was all-cause 30-day readmission rate. Secondary outcomes included 90-day readmission rate, rates of complications related to OPAT, emergency department visits during OPAT, and predictors of all-cause 30-day readmission through a logistic regression analysis.

Results

Two hundred individual patients were included in the analysis; 60% were male and the mean age was 49 years. The most common indications for OPAT at home were bone and joint infection (52%) and bacteremia (26%). Forty patients (20%) experienced an unplanned, all-cause 30-day readmission, with a total of 48 readmission events. Of the 40 patients who were readmitted within 30 days, 20 (50%) were due to non-OPAT related reasons. Sixty patients (30%) experienced an OPAT-related complication, and chronic kidney disease was found to be an independent predictor of readmission (OR: 2.8, 95% CI: 1.0-7.6).

Conclusions

Patients receiving OPAT at home are at increased risk for early hospital readmission, but it is often due to reasons not associated with OPAT. Patients with chronic kidney disease beginning OPAT at home should be closely monitored after discharge.

Clinical Outcomes of an Innovative Cefazolin Delivery Program for MSSA Infections in OPAT

Cefazolin is a recommended treatment for methicillin-susceptible Staphylococcus aureus (MSSA) infections that has been successfully used in outpatient parenteral antibiotic therapy (OPAT) programs. The aim of this study was to assess the clinical outcomes of cefazolin delivered each day (Group 24) vs. every two days (Group 48) for MSSA infections in OPAT programs. It was a prospective observational study with retrospective analysis of a cohort of MSSA infections attended in OPAT. The primary outcome was treatment success, defined as completing the antimicrobial regimen without death, treatment discontinuation, or readmission during treatment and follow-up. A univariate and multivariate logistic regression model was built. A two-sided p < 0.05 was considered statistically significant. Of the 149 MSSA infections treated with cefazolin 2 g/8 h in OPATs, 94 and 55 patients were included in the delivery Group 24 and Group 48, respectively. Treatment failure and unplanned readmission rates were similar in both groups (11.7% vs. 7.3% p = 0.752 and 8.5% vs. 5.5% p = 0.491). There was a significant increase in vascular access complications in Group 24 (33.0%) with respect to Group 48 (7.3%) (p < 0.001). Treating uncomplicated MSSA infection with cefazolin home-delivered every two days through an OPAT program is not associated with an increased risk of treatment failure and entails a significant reduction in resource consumption compared to daily delivery.

Oral step-down therapy in patients with uncomplicated Staphylococcus aureus primary bacteremia and catheter-related bloodstream infections

Patients with uncomplicated Staphylococcus aureus primary bacteremia and catheter-related bloodstream infection (CRBSI) should be treated for at least 14 days. However, evidence for oral step-down therapy is lacking in these patients. A retrospective cohort was identified from 2013 to 2018 in a 1,950-bed tertiary hospital. An oral antimicrobial therapy (OAT) group was defined as patients treated with oral antibiotics following less than 10 days of intravenous antimicrobial therapy (IAT). Treatment failure was defined as any case of recurrence or death within 90 days. A total of 103 patients were included in the analysis, including 32 patients treated with OAT. Rates of treatment failure were 3.2% and 12.7% in the OAT and IAT groups (P = 0.113). The length of hospital stay was shorter in the OAT group. OAT was not an independent risk factor for treatment failure. OAT may reduce the duration of hospitalization without adverse effects in these patients.