Top Questions in Uncomplicated, Non-Staphylococcus aureus Bacteremia

Association of Follow-up Blood Cultures With Mortality in Patients With Gram-Negative Bloodstream Infections: A Systematic Review and Meta-analysis

Importance

Obtaining follow-up blood cultures (FUBCs) in patients with Staphylococcus aureus bloodstream infection (BSI) is standard practice, although its utility in patients with gram-negative bacterial BSI (GN-BSI) is unclear.

Objective

To examine whether obtaining FUBCs is associated with decreased mortality (key question [KQ] 1) and whether positive vs negative FUBCs are associated with increased mortality (KQ2).

Data Sources

MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Web of Science, and gray literature were searched from inception to March 11, 2022.

Study Selection

Two investigators used predefined eligibility criteria to independently screen titles, abstracts, and relevant full texts. Randomized clinical trials or observational studies that matched or statistically adjusted for differences in, at minimum, level of acute illness between patients in the intervention (eg, FUBCs obtained) and control (eg, FUBCs not obtained) groups were included in primary analyses. Articles published in languages other than English were excluded.

Data Extraction and Synthesis

Data abstraction and quality assessments were performed by one investigator and verified by a second investigator. Risk of bias was assessed with the Newcastle-Ottawa Scale. Effect sizes were pooled using random-effects models. The study followed the Meta-analysis of Observational Studies in Epidemiology (MOOSE) reporting guideline.

Main Outcomes and Measures

Mortality before hospital discharge or up to 30 days from the index blood culture.

Results

From 3495 studies, 15 were included (all nonrandomized). In the 5 studies (n = 4378 patients) that met criteria for the KQ1 primary analysis, obtaining FUBCs was associated with decreased mortality (hazard ratio, 0.56; 95% CI, 0.45-0.71). For KQ2, 2 studies met criteria for the primary analysis (ie, matched or statistically adjusted for differences in patients with positive vs negative FUBCs), so an exploratory meta-analysis of all 9 studies that investigated KQ2 (n = 3243 patients) was performed. Positive FUBCs were associated with increased mortality relative to negative blood cultures (odds ratio, 2.27; 95% CI, 1.54-3.34). Limitations of the literature included a lack of randomized studies and few patient subgroup analyses.

Conclusions and Relevance

In this systematic review and meta-analysis, obtaining FUBCs in patients with GN-BSI was associated with decreased mortality. The benefit of FUBCs may stem from identification of patients with positive FUBCs, which was a poor prognostic marker.

Early oral stepdown antibiotic therapy versus continuing intravenous therapy for uncomplicated Gram-negative bacteraemia (the INVEST trial): study protocol for a multicentre, randomised controlled, open-label, phase III, non-inferiority trial

Background

The incidence of Gram-negative bacteraemia is rising globally and remains a major cause of morbidity and mortality. The majority of patients with Gram-negative bacteraemia initially receive intravenous (IV) antibiotic therapy. However, it remains unclear whether patients can step down to oral antibiotics after appropriate clinical response has been observed without compromising outcomes. Compared with IV therapy, oral therapy eliminates the risk of catheter-associated adverse events, enhances patient quality of life and reduces healthcare costs. As current management of Gram-negative bacteraemia entails a duration of IV therapy with limited evidence to guide oral conversion, we aim to evaluate the clinical efficacy and economic impact of early stepdown to oral antibiotics.

Methods

This is an international, multicentre, randomised controlled, open-label, phase III, non-inferiority trial. To be eligible, adult participants must be clinically stable / non-critically ill inpatients with uncomplicated Gram-negative bacteraemia. Randomisation to the intervention or standard arms will be performed with 1:1 allocation ratio. Participants randomised to the intervention arm (within 72 h from index blood culture collection) will be immediately switched to an oral fluoroquinolone or trimethoprim-sulfamethoxazole. Participants randomised to the standard arm will continue to receive IV therapy for at least 24 h post-randomisation before clinical re-assessment and decision-making by the treating doctor. The recommended treatment duration is 7 days of active antibiotics (including empiric therapy), although treatment regimen may be longer than 7 days if clinically indicated. Primary outcome is 30-day all-cause mortality, and the key secondary outcome is health economic evaluation, including estimation of total healthcare cost as well as assessment of patient quality of life and number of quality-adjusted life years saved. Assuming a 30-day mortality of 8% in the standard and intervention arms, with 6% non-inferiority margin, the target sample size is 720 participants which provides 80% power with a one-sided 0.025 α-level after adjustment for 5% drop-out.

Discussion

A finding of non-inferiority in efficacy of oral fluoroquinolones or trimethoprim-sulfamethoxazole versus IV standard of care antibiotics may hypothetically translate to wider adoption of a more cost-effective treatment strategy with better quality of life outcomes.

Trial registration

ClinicalTrials.govNCT05199324. Registered 20 January 2022.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06495-3.

The Changing Landscape of Uncomplicated Gram-Negative Bacteremia: A Narrative Review to Guide Inpatient Management

Gram-negative bacteremia secondary to focal infection such as skin and soft-tissue infection, pneumonia, pyelonephritis, or urinary tract infection is commonly encountered in hospital care. Current practice guidelines lack sufficient detail to inform evidence-based practices. Specifically, antimicrobial duration, criteria to transition from intravenous to oral step-down therapy, choice of oral antimicrobials, and reassessment of follow-up blood cultures are not addressed. The presence of bacteremia is often used as a justification for a prolonged course of antimicrobial therapy regardless of infection source or clinical response. Antimicrobials are lifesaving but not benign. Prolonged antimicrobial exposure is associated with adverse effects, increased rates of Clostridioides difficile infection, antimicrobial resistance, and longer hospital length of stay. Emerging evidence supports shorter overall duration of antimicrobial treatment and earlier transition to oral agents among patients with uncomplicated Enterobacteriaceae bacteremia who have achieved adequate source control and demonstrated clinical stability and improvement. After appropriate initial treatment with an intravenous antimicrobial, transition to highly bioavailable oral agents should be considered for total treatment duration of 7 days. Routine follow-up blood cultures are not cost-effective and may result in unnecessary healthcare resource utilization and inappropriate use of antimicrobials. Clinicians should incorporate these principles into the management of gram-negative bacteremia in the hospital.

Impact of an Antimicrobial Stewardship Bundle for Uncomplicated Gram-Negative Bacteremia

BACKGROUND

Recent studies in gram-negative bacteremia (GNB) suggest that intravenous (IV) to oral (PO) switch and short treatment durations yield similar clinical outcomes and fewer adverse events. Antimicrobial stewardship program (ASP) bundled initiatives have been associated with improved clinical outcomes for bloodstream infections.

METHODS

This single-center retrospective cohort evaluation included inpatient adults from 11/2014-10/2015 and 10/2017-9/2018 with GNB. The pre-ASP period was before the establishment of an ASP program. In the post period, the ASP promoted IV-to-PO switches, avoidance of repeat blood cultures, and short treatment durations for patients with uncomplicated GNB. The primary outcome was duration of antibiotic therapy. Secondary outcomes included process measures associated with the bundle and clinical outcomes.

RESULTS

One hundred thirty-seven patients met criteria for inclusion, with 51 patients in the pre group and 86 patients in the post group. Background characteristics were similar between groups. The median duration of therapy (interquartile range) was 14 (10-16) days in the pre group and 10 days (7-14) in the post group (P < .001). The median day of IV-to-PO switch was day 5 (4-6) in the pre group vs day 4 (3-5) in the post group (P = .046). The average total hospital cost per case decreased by 27% in the post group (P = .19). Mortality rates and bacteremia recurrence were not significantly different between groups.

CONCLUSIONS

An ASP bundle for uncomplicated GNB was associated with reduced durations of therapy and earlier PO switch. These findings highlight the synergistic role of ASPs in optimizing antibiotic use and promoting patient safety.