Implications of reducing antibiotic treatment duration for antimicrobial resistance in hospital settings: A modelling study and meta-analysis

Stop antibiotics when you feel better? Opportunities, challenges and research directions

Shortening standard antibiotic courses and stopping antibiotics when patients feel better are two ways to reduce exposure to antibiotics in the community, and decrease the risks of antimicrobial resistance and antibiotic side effects. While evidence shows that shorter antibiotic treatments are non-inferior to longer ones for infections that benefit from antibiotics, shorter courses still represent average treatment durations that might be suboptimal for some. In contrast, stopping antibiotics based on improvement or resolution of symptoms might help personalize antibiotic treatment to individual patients and help reduce unnecessary exposure. Yet, many challenges need addressing before we can consider this approach evidence-based and implement it in practice. In this viewpoint article, we set out the main evidence gaps and avenues for future research.

The evidence base for the optimal antibiotic treatment duration of upper and lower respiratory tract infections: an umbrella review

BACKGROUND

Many trials, reviews, and meta-analyses have been performed on the comparison of short versus long antibiotic treatment in respiratory tract infections, generally supporting shorter treatment. The aim of this umbrella review is to assess the soundness of the current evidence base for optimal antibiotic treatment duration.

METHODS

A search in Ovid MEDLINE, Embase, and Clarivate Analytics Web of Science Core Collection was performed on May 1, 2024, without date and language restrictions. Systematic reviews addressing treatment durations in community-acquired pneumonia (CAP), acute exacerbation of chronic obstructive pulmonary disease (AECOPD), hospital-acquired pneumonia (HAP), acute sinusitis, and streptococcal pharyngitis, tonsillitis, or pharyngotonsillitis were included. Studies from inpatient and outpatient settings were included; reviews in paediatric populations were excluded. Outcomes of interest were clinical and bacteriological cure, microbiological eradication, mortality, relapse rate, and adverse events. The quality of the reviews was assessed using the AMSTAR 2 tool, risk of bias of all included randomised controlled trials (RCTs) using the Cochrane risk-of-bias tool (version 1), and overall quality of evidence according to GRADE.

FINDINGS

We identified 30 systematic reviews meeting the criteria; they were generally of a low to critically low quality. 21 reviews conducted a meta-analysis. For CAP outside the intensive care unit (ICU; 14 reviews, of which eight did a meta-analysis) and AECOPD (eight reviews, of which five did a meta-analysis), there was sufficient evidence supporting a treatment duration of 5 days; evidence for shorter durations is scarce. Evidence on non-ventilator-associated HAP is absent, despite identifying three reviews (of which one did a meta-analysis), since no trials were conducted exclusively in this population. For sinusitis the evidence appears to support a shorter regimen, but more evidence is needed in the population who actually require antibiotic treatment. For pharyngotonsillitis (eight reviews, of which six did a meta-analysis), sufficient evidence exists to support short-course cephalosporin but not short-course penicillin when dosed three times a day.

INTERPRETATION

The available evidence for non-ICU CAP and AECOPD supports a short-course treatment duration of 5 days in patients who have clinically improved. Efforts of the scientific community should be directed at implementing this evidence in daily practice. High-quality RCTs are needed to underpin even shorter treatment durations for CAP and AECOPD, to establish the optimal treatment duration of HAP and acute sinusitis, and to evaluate shorter duration using an optimal penicillin dosing schedule in patients with pharyngotonsillitis.

FUNDING

None.

Exploring Prior Antibiotic Exposure Characteristics for COVID-19 Hospital Admission Patients: OpenSAFELY

Previous studies have demonstrated the association between antibiotic use and severe COVID-19 outcomes. This study aimed to explore detailed antibiotic exposure characteristics among COVID-19 patients. Using the OpenSAFELY platform, which integrates extensive health data and covers 40% of the population in England, the study analysed 3.16 million COVID-19 patients with at least two prior antibiotic prescriptions. These patients were compared to up to six matched controls without hospitalisation records. A machine learning model categorised patients into ten groups based on their antibiotic exposure history over the three years before their COVID-19 diagnosis. The study found that for COVID-19 patients, the total number of prior antibiotic prescriptions, diversity of antibiotic types, broad-spectrum antibiotic prescriptions, time between first and last antibiotics, and recent antibiotic use were associated with an increased risk of severe COVID-19 outcomes. Patients in the highest decile of antibiotic exposure had an adjusted odds ratio of 4.8 for severe outcomes compared to those in the lowest decile. These findings suggest a potential link between extensive antibiotic use and the risk of severe COVID-19. This highlights the need for more judicious antibiotic prescribing in primary care, primarily for patients with higher risks of infection-related complications, which may better offset the potential adverse effects of repeated antibiotic use.

The devil's in the defaults: An interrupted time-series analysis of the impact of default duration elimination on exposure to fluoroquinolone therapy

OBJECTIVE

To determine whether removal of default duration, embedded in electronic prescription (e-script), influenced antibiotic days of therapy.

DESIGN

Interrupted time-series analysis.

SETTING

The study was conducted across 2 community hospitals, 1 academic hospital, 3 emergency departments, and 86 ambulatory clinics.

PATIENTS

Adults prescribed a fluoroquinolone with a duration <31 days.

INTERVENTIONS

Removal of standard 10-day fluoroquinolone default duration and addition of literature-based duration guidance in the order entry on December 19, 2017. The study period included data for 12 months before and after the intervention.

RESULTS

The study included 35,609 fluoroquinolone e-scripts from the preintervention period and 31,303 fluoroquinolone e-scripts from the postintervention period, accounting for 520,388 cumulative fluoroquinolone DOT. Mean durations before and after the intervention were 7.8 (SD, 4.3) and 7.7 (SD, 4.5), a nonsignificant change. E-scripts with a 10-day duration decreased prior to and after the default removal. The inpatient setting showed a significant 8% drop in 10-day e-scripts after default removal and a reduced median duration by 1 day; 10-day scripts declined nonsignificantly in ED and ambulatory settings. In the ambulatory settings, both 7- and 14-day e-script durations increased after default removal.

CONCLUSION

Removal of default 10-day antibiotic durations did not affect overall mean duration but did shift patterns in prescribing, depending on practice setting. Stewardship interventions must be studied in the context of practice setting. Ambulatory stewardship efforts separate from inpatient programs are needed because interventions cannot be assumed to have similar effects.

Individualised, short-course antibiotic treatment versus usual long-course treatment for ventilator-associated pneumonia (REGARD-VAP): a multicentre, individually randomised, open-label, non-inferiority trial

BACKGROUND

Ventilator-associated pneumonia (VAP) is associated with increased mortality, prolonged hospitalisation, excessive antibiotic use and, consequently, increased antimicrobial resistance. In this phase 4, randomised trial, we aimed to establish whether a pragmatic, individualised, short-course antibiotic treatment strategy for VAP was non-inferior to usual care.

METHODS

We did an individually randomised, open-label, hierarchical non-inferiority-superiority trial in 39 intensive care units in six hospitals in Nepal, Singapore, and Thailand. We enrolled adults (age ≥18 years) who met the US Centers for Disease Control and Prevention National Healthcare Safety Network criteria for VAP, had been mechanically ventilated for 48 h or longer, and were administered culture-directed antibiotics. In culture-negative cases, empirical antibiotic choices were made depending on local hospital antibiograms reported by the respective microbiology laboratories or prevailing local guidelines. Participants were assessed until fever resolution for 48 h and haemodynamic stability, then randomly assigned (1:1) to individualised short-course treatment (≤7 days and as short as 3-5 days) or usual care (≥8 days, with precise durations determined by the primary clinicians) via permuted blocks of variable sizes (8, 10, and 12), stratified by study site. Independent assessors for recurrent pneumonia and participants were masked to treatment allocation, but clinicians were not. The primary outcome was a 60-day composite endpoint of death or pneumonia recurrence. The non-inferiority margin was prespecified at 12% and had to be met by analyses based on both intention-to-treat (all study participants who were randomised) and per-protocol populations (all randomised study participants who fulfilled the eligibility criteria, met fitness criteria for antibiotic discontinuation, and who received antibiotics for the duration specified by their allocation group). This study is registered with ClinicalTrials.gov, number NCT03382548.

FINDINGS

Between May 25, 2018, and Dec 16, 2022, 461 patients were enrolled and randomly assigned to the short-course treatment group (n=232) or the usual care group (n=229). Median age was 64 years (IQR 51-74) and 181 (39%) participants were female. 460 were included in the intention-to-treat analysis after excluding one withdrawal (231 in the short-course group and 229 in the usual care group); 435 participants received the allocated treatment and fulfilled eligibility criteria, and were included in the per-protocol population. Median antibiotic treatment duration for the index episodes of VAP was 6 days (IQR 5-7) in the short-course group and 14 days (10-21) in the usual care group. 95 (41%) of 231 participants in the short-course group met the primary outcome, compared with 100 (44%) of 229 in the usual care group (risk difference -3% [one-sided 95% CI -∞ to 5%]). Results were similar in the per-protocol population. Non-inferiority of short-course antibiotic treatment was met in the analyses, although superiority compared with usual care was not established. In the per-protocol population, antibiotic side-effects occurred in 86 (38%) of 224 in the usual care group and 17 (8%) of 211 in the short-course group (risk difference -31% [95% CI -37 to -25%; p<0·0001]).

INTERPRETATION

In this study of adults with VAP, individualised shortened antibiotic duration guided by clinical response was non-inferior to longer treatment durations in terms of 60-day mortality and pneumonia recurrence, and associated with substantially reduced antibiotic use and side-effects. Individualised, short-course antibiotic treatment for VAP could help to reduce the burden of side-effects and the risk of antibiotic resistance in high-resource and resource-limited settings.

FUNDING

UK Medical Research Council; Singapore National Medical Research Council.

TRANSLATIONS

For the Thai and Nepali translations of the abstract see Supplementary Materials section.

Shorter versus longer-course of antibiotic therapy for urinary tract infections in pediatric population: an updated meta-analysis

Urinary tract infections (UTI) affect between 3% to 7.5% of the febrile pediatric population each year, being one of the most common bacterial infections in pediatrics. Nevertheless, there is no consensus in the medical literature regarding the duration of per oral (p.o.) antibiotic therapy for UTI among these patients. Therefore, our meta-analysis aims to assess the most effective therapy length in this scenario. PubMed, Cochrane, and Embase were searched for randomized controlled trials (RCTs) comparing short (≤ 5 days) with long-course (≥ 7 days) per os (p.o.) antibiotic therapy for children with UTI. Statistical analysis was performed using R Studio version 4.2.1, heterogeneity was assessed with I2 statistics, and the risk of bias was evaluated using the RoB-2 tool. Risk Ratios (RR) with p < 0.05 were considered statistically significant. Seventeen studies involving 1666 pediatric patients were included. Of these, 890 patients (53.4%) were randomized to receive short-course therapy. Patients undergoing short-course therapy showed higher treatment failure rates (RR 1.61; 95% CI 1.15-2.27; p = 0.006). Furthermore, there were no statistically significant differences between groups regarding reinfection (RR 0.73; 95% CI 0.47-1.13; p = 0156) and relapse rates (RR 1.47; 95% CI 0.8-2.71; p = 0.270).  Conclusion: In summary, our results suggest that long-course p.o. antibiotic therapy is associated with a lower rate of treatment failure when compared to short-course p.o. antibiotic therapy. There was no statistical difference between both courses regarding reinfection and relapse rates within 15 months.    PROSPERO identifier: CRD42023456745. What is Known: • Urinary tract infections (UTIs) are common in children, affecting around 7.5% of those under 18. • The optimal duration of antibiotic treatment for pediatric UTIs has been a subject of debate. What is New: • Short-course therapy (5 or fewer days) was associated with a significantly higher failure rate when compared to long-course therapy. • There was no significant difference in reinfection and relapse rates within 15 months between short and long-course therapy.

Antibacterial Potential of Symmetrical Twin-Drug 3,6-Diaminoxanthones

Global health faces a significant issue with the rise of infectious diseases caused by bacteria, fungi, viruses, and parasites. The increasing number of multi-drug resistant microbial pathogens severely threatens public health worldwide. Antibiotic-resistant pathogenic bacteria, in particular, present a significant challenge. Therefore, there is an urgent need to identify new potential antimicrobial targets and discover new chemical entities that can potentially reverse bacterial resistance. The main goal of this research work was to create and develop a library of 3,6-disubstituted xanthones based on twin drugs and molecular extension approaches to inhibit the activity of efflux pumps. The process involved synthesizing 3,6-diaminoxanthones through the reaction of 9-oxo-9H-xanthene-3,6-diyl bis(trifluoromethanesulfonate) with various primary and secondary amines. The resulting 3,6-disubstituted xanthone derivatives were then tested for their in vitro antimicrobial properties against a range of pathogenic strains and their efficacy in inhibiting the activity of efflux pumps, biofilm formation, and quorum-sensing. Several compounds have exhibited effective antibacterial properties against the Gram-positive bacterial species tested. Xanthone 16, in particular, has demonstrated exceptional efficacy with a remarkable MIC of 11 µM (4 µg/mL) against reference strains Staphylococcus aureus ATCC 25923 and Enterococcus faecalis ATCC 29212, and 25 µM (9 µg/mL) against methicillin-resistant S. aureus 272123. Furthermore, some derivatives have shown potential as antibiofilm agents in a crystal violet assay. The ethidium bromide accumulation assay pinpointed certain compounds inhibiting bacterial efflux pumps. The cytotoxic effect of the most promising compounds was examined in mouse fibroblast cell line NIH/3T3, and two monoamine substituted xanthone derivatives with a hydroxyl substituent did not exhibit any cytotoxicity. Overall, the nature of the substituent was critical in determining the antimicrobial spectra of aminated xanthones.

Short-term versus usual-term antibiotic treatment for uncomplicated Staphylococcus aureus bacteremia: a systematic review and meta-analysis

Introduction

Uncomplicated Staphylococcus aureus bacteremia remains a leading cause of morbidity and mortality in hospitalized patients. Current guidelines recommend a minimum of 14 days of treatment.

Objective

To evaluate the efficacy and safety of short versus usual antibiotic therapy in adults with uncomplicated S. aureus bacteremia (SAB).

Methods

We developed a search strategy to identify systematic review and meta-analysis of non-randomized studies (NRS), comparing short versus usual or long antibiotic regimens for uncomplicated SAB in MEDLINE, Embase, and the Cochrane Register up to June 2023. The risk of bias was assessed using the ROBINS I tool. The meta-analysis was performed using Review Manager software with a random effect model.

Results

Six NRS with a total of 1700 patients were included. No significant differences were found when comparing short versus prolonged antibiotic therapy as defined by the authors for 90-day mortality [odds ratio (OR): 1.09; 95% confidence interval (CI): 0.82-1.46, p: 0.55; I2 = 0%] or 90-day recurrence or relapse of bacteremia [OR: 0.72; 95% CI: 0.31-1.68, p: 0.45; I2 = 26%]. Sensitivity analysis showed similar results when comparing a predefined duration of <14 days versus ⩾14 days and when excluding the only study with a high risk of bias.

Conclusion

Shorter-duration regimens could be considered as an alternative option for uncomplicated SAB in low-risk cases. However, based on a small number of studies with significant methodological limitations and risk of bias, the benefits and harms of shorter regimens should be analyzed with caution. Randomized clinical trials are needed to determine the best approach regarding the optimal duration of therapy.