Early Oral Switch to Linezolid for Low-risk Patients With Staphylococcus aureus Bloodstream Infections: A Propensity-matched Cohort Study

Differences in oxazolidinone resistance mechanisms and small colony variants emergence of Staphylococcus aureus induced in an in vitro resistance development model

Invasive Staphylococcus aureus infections are associated with a high burden of disease, case fatality rate and healthcare costs. Oxazolidinones such as linezolid and tedizolid are considered potential treatment choices for conditions involving methicillin resistance or penicillin allergies. Additionally, they are being investigated as potential inhibitors of toxins in toxin-mediated diseases. In this study, linezolid and tedizolid were evaluated in an in vitro resistance development model for induction of resistance in S. aureus. Whole genome sequencing was conducted to elucidate resistance mechanisms through the identification of causal mutations. After inducing resistance to both linezolid and tedizolid, several partially novel single nucleotide variants (SNVs) were detected in the rplC gene, which encodes the 50S ribosome protein L3 in S. aureus. These SNVs were found to decrease the binding affinity, potentially serving as the underlying cause for oxazolidinone resistance. Furthermore, in opposite to linezolid we were able to induce phenotypically small colony variants of S. aureus after induction of resistance with tedizolid for the first time in literature. In summary, even if different antibiotic concentrations were required and SNVs were detected, the principal capacity of S. aureus to develop resistance to oxazolidinones seems to differ between linezolid and tedizolid in-vivo but not in vitro. Stepwise induction of resistance seems to be a time and cost-effective tool for assessing resistance evolution. Inducted-resistant strains should be examined and documented for epidemiological reasons, if MICs start to rise or oxazolidinone-resistant S. aureus outbreaks become more frequent.

A Case Series on Serotonin Syndrome from Concomitant use of linezolid With Methadone, Buprenorphine, and/or Dextroamphetamine

Background and Objectives: The risk of serotonin syndrome (SS), especially when linezolid is used concomitantly with methadone, buprenorphine, and/or dextroamphetamine, remains widely unstudied and may limit the options for antimicrobial therapy in these patient populations. Methods: We reviewed all adult encounters on linezolid with concomitant methadone, buprenorphine, and/or dextroamphetamine from April 2016 to June 2022. The primary outcomes included characterizing prescribing preferences and prevalence of confirmed and possible serotonin syndrome using ICD-10 diagnosis codes, cyproheptadine administration, and electronic medical record chart review using the Hunter Serotonin Toxicity Criteria. Results: Overall, 194 encounters were evaluated. 16.5%, 17.8%, and 7.1% were on high dose methadone, buprenorphine, and dextroamphetamine, respectively. Mean duration of overlap with linezolid was 4.6, 3.3, and 7 days respectively. One confirmed and two possible cases of serotonin syndrome were identified. Conclusion: Linezolid may be considered in patients who are concomitantly on methadone, buprenorphine, and/or dextroamphetamine. In our analysis of 194 encounters, one definitive case and two possible cases of SS were identified. Additional real-world studies are necessary to identify if exposure and/or duration may be correlated with an increased risk of serotonin syndrome.

Effectiveness of antibiotic therapy for early recurrence of peritonsillar cellulitis and abscesses: A retrospective cohort study

OBJECTIVE

Short-term recurrence is common in patients with peritonsillar cellulitis and abscesses, leading to socioeconomic problems. Early switching from intravenous to oral antibiotics is feasible for treating certain diseases. However, reports on early switching and total antibiotic administration duration in peritonsillar cellulitis and abscesses are limited. This study aimed to determine the appropriate antibiotic therapy duration and examine the impact of early oral switch therapy on peritonsillar cellulitis and abscesses.

METHODS

We retrospectively identified 98,394 patients who received antibiotic therapy during hospitalization for peritonsillar cellulitis and abscesses between July 1, 2010, and December 31, 2019, using the Japanese Diagnosis Procedure Combination database.

RESULTS

Propensity score matching analysis revealed no significant between-group difference in the rehospitalization rate (early oral switch therapy and long intravenous therapy: 1.7 % [198 of 11,621] vs. 2.0 % [234 of 11,621], odds ratio [OR] 0.84, 95 % confidence interval [CI] 0.70-1.02). A long total duration of antibiotic therapy (reference: 1-9 days) was associated with a low risk of rehospitalization (10-14 days: OR 0.86, 95 % CI 0.78-0.95; 15+ days: OR 0.51, 95 % CI 0.38-0.66).

CONCLUSION

Early oral switch therapy may be a viable option for treating patients with peritonsillar cellulitis and abscesses in good condition who can tolerate oral intake. No less than 10 days of antibiotic therapy is desirable.

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.

Safety and effectiveness of fifth generation cephalosporins for the treatment of methicillin-resistant staphylococcus aureus bloodstream infections: a narrative review exploring past, present, and future

INTRODUCTION

Methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection (BSI) is a major issue in healthcare, since it is often associated with endocarditis or deep site foci. Relevant morbidity and mortality associated with MRSA-BSIs forced the development of new antibiotic strategies; in particular, this review will focus the attention on fifth-generation cephalosporins (ceftaroline/ceftobiprole), that are the only ß-lactams active against MRSA.

AREAS COVERED

The review discusses the available randomized controlled trials and real-world observational studies conducted on safety and effectiveness of ceftaroline/ceftobiprole for the treatment of MRSA-BSIs. Finally, a proposal of MRSA-BSI treatment flowchart, based on fifth-generation cephalosporins, is described.

EXPERT OPINION

The use of anti-MRSA cephalosporins is an acceptable choice either in monotherapy or combination therapy for the treatment of MRSA-BSIs due to their relevant effectiveness and safety. Particularly, their use may be advisable in combination therapy in case of severe infections (including endocarditis or persistent bacteriemia) or in monotherapy in subjects at higher risk of drugs-induced toxicity with older regimens. On the contrary, caution should be taken in case of suspected/ascertained central nervous system infections due to inconsistent data regarding penetration of these drugs in cerebrospinal fluid and brain tissues.

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.

Intravenous versus Partial Oral Antibiotic Therapy in the Treatment of Uncomplicated Bloodstream Infection Due to Streptococcus Species

This retrospective cohort study examines effectiveness of partial oral antibiotic regimens in uncomplicated bloodstream infections (BSIs) due to Streptococcus species compared to standard intravenous therapy. Adult patients with uncomplicated streptococcal BSIs from April 2016 to June 2020 in seven hospitals in South Carolina, USA, were evaluated. Multivariate Cox proportional hazards regression was used to examine the time to treatment failure within 90 days of a BSI after adjustment for the propensity to receive partial oral therapy. Multivariate linear regression was used to examine the hospital length of stay (HLOS). Among the 222 patients included, 99 received standard intravenous antibiotics and 123 received partial oral therapy. Of the standard intravenous therapy group, 46/99 (46.5%) required outpatient parenteral antibiotic therapy (OPAT). There was no difference in the risk of treatment failure between partial oral and standard intravenous therapy (hazards ratio 0.53, 95% CI 0.18, 1.60; p = 0.25). Partial oral therapy was independently associated with a shorter HLOS after adjustments for the propensity to receive partial oral therapy and other potential confounders (-2.23 days, 95% CI -3.53, -0.94; p < 0.001). Transitioning patients to oral antibiotics may be a reasonable strategy in the management of uncomplicated streptococcal BSIs. Partial oral therapy does not seem to have a higher risk of treatment failure and may spare patients from prolonged hospitalizations and OPAT complications.

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.

Comparison of Oral and Intravenous Definitive Antibiotic Therapy for Beta-Hemolytic Streptococcus Species Bloodstream Infections from Soft Tissue Sources: a Propensity Score-Matched Analysis

Beta-hemolytic streptococci are common causes of bloodstream infection (BSI). There is emerging data regarding oral antibiotics for BSI but limited for beta-hemolytic streptococcal BSI. We conducted a retrospective study of adults with beta-hemolytic streptococcal BSI from a primary skin/soft tissue source from 2015 to 2020. Patients transitioned to oral antibiotics within 7 days of treatment initiation were compared to those who continued intravenous therapy, after propensity score matching. The primary outcome was 30-day treatment failure (composite of mortality, infection relapse, and hospital readmission). A prespecified 10% noninferiority margin was used for the primary outcome. We identified 66 matched pairs of patients treated with oral and intravenous antibiotics as definitive therapy. Based on an absolute difference in 30-day treatment failure of 13.6% (95% confidence interval 2.4 to 24.8%), the noninferiority of oral therapy was not confirmed (P = 0.741); on the contrary, the superiority of intravenous antibiotics is suggested by this difference. Acute kidney injury occurred in two patients who received intravenous treatment and zero who received oral therapy. No patients experienced deep vein thrombosis or other vascular complications related to treatment. In patients treated for beta-hemolytic streptococcal BSI, those who transitioned to oral antibiotics by day 7 showed higher rates of 30-day treatment failure than propensity-matched patients. This difference may have been driven by underdosing of oral therapy. Further investigation into optimal antibiotic choice, route, and dosing for definitive therapy of BSI is needed.

Oral stepdown in Gram-positive bloodstream infections: A step in the right direction

Bloodstream infections (BSIs) due to Gram-positive organisms have traditionally been treated with prolonged courses of intravenous antimicrobials. However, this dogma is associated with substantial burden to the patient and health care system. Consequently, there is growing interest in the utilization of oral stepdown therapy, defined as the transition of intravenous therapy to an active oral agent, for this indication. This review highlights available literature examining oral stepdown in adult patients with BSI due to commonly encountered Gram-positive pathogens, including Staphylococcus aureus, Streptococcus spp., and Enterococcus spp. Support for oral stepdown in this setting is primarily derived from observational studies subject to selection bias. Nevertheless, this treatment strategy exhibits promising potential in carefully selected patients as it is consistently associated with reductions in hospital length of stay without jeopardizing clinical cure or survivability. Prospective, randomized trials are needed for validation of oral stepdown in Gram-positive BSI and to identify the optimal patient population and regimen.

Uncomplicated Streptococcal Bacteremia: The Era of Oral Antibiotic Step-down Therapy?

BACKGROUND

The purpose of this study was to compare the clinical outcomes of adults with uncomplicated streptococcal bacteremia who received either oral (PO) step-down or continued intravenous (IV) therapy.

METHODS

This was a retrospective, single-center, cohort study, including adults admitted with Streptococcal bloodstream infection between January 1, 2013, and December 31, 2020. Only patients with uncomplicated Streptococcal bloodstream infections were included. Patients who transitioned to PO therapy within 5 days from bacteremia onset were compared to patients receiving continued IV therapy. The primary outcome was clinical failure, defined by either 90-day hospital readmission or mortality. Secondary outcomes included hospital length of stay (LOS) and antibiotic-related adverse events (AAEs).

RESULTS

Of the 264 patients included, 42% were transitioned to PO therapy. Group B Streptococcus (22.7%) was the most common isolate. The most common sources of infection were skin and soft tissue (35%) and pulmonary (25%). Intensive care unit (ICU) stay was more common in the continued IV therapy group (22.2%) than in the PO step-down group (5.4%). The frequency of clinical failure was similar in the IV and PO groups (24.2% vs. 18.0%, P=0.23). The IV group had longer hospital LOS (median, [interquartile range (IQR)]) compared with the PO group (7 [5-13.5] vs. 4 [3-5] days, P<0.001). The incidence of AAEs was similar in the IV and PO groups (1.3% vs. 1.8%, P=0.74).

CONCLUSION

Oral antibiotic step-down therapy may be appropriate for the treatment of uncomplicated Streptococcal bacteremia, with consideration of factors such as patient comorbidities, type of infection, source control and clinical progress.

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.

Impact of 18F-FDG-PET/CT on the management of Staphylococcus aureus bacteraemia: a retrospective observational study

OBJECTIVES

To assess the impact of ¹⁸F-FDG-PET/CT on the diagnosis and management of patients with Staphylococcus aureus bacteraemia (SAB).

METHODS

Post hoc analysis of a prospective cohort of consecutive adult patients diagnosed with SAB (January 2013-December 2017). Patients who underwent ¹⁸F-FDG-PET/CT at the discretion of the attending physician were included. Endpoints were the identification of previously unknown infectious foci and changes in clinical management, defined as changes in the duration or class of antibiotic therapy, a surgical procedure on the source of infection or a change in the decision to remove or retain an implantable device.

RESULTS

We included 39 patients (median age: 69 years, IQR:60-79). Fifteen (39%) patients did not have an infectious focus identified before ¹⁸F-FDG-PET/CT). Thirty new infectious foci were detected in 22/39 (56%) patients. In 11/15 (73%) patients without an identified focus at least one infectious focus was detected by ¹⁸F-FDG-PET/CT. In 22/26 (85%) patients with implantable devices, ¹⁸F-FDG-PET/CT confirmed or ruled out infection or detected local complications. Out of 13 device infections, 10 were detected by ¹⁸F-FDG-PET/CT (7/10 for the first time). In 19/39 (49%) patients ¹⁸F-FDG-PET/CT results led to changes in clinical management (15 changes in antibiotic therapy, 2 device removals, 2 surgical procedures, 1 avoidance of a surgical procedure).

CONCLUSIONS

¹⁸F-FDG-PET/CT may be a useful asset in the management of selected SAB cases, allowing the identification of previously undetected infectious foci and optimization of therapy, particularly in patients with endovascular devices. Indication should be made on a case-by-case basis.

Clofazimine as a comparator for preclinical efficacy evaluations of experimental therapeutics against pulmonary M. abscessus infection in mice

Mycobacteroides abscessus (Mab, also known as Mycobacterium abscessus) can cause chronic pulmonary disease in the setting of structural lung conditions. Current treatment recommendations require at least one year of daily therapy with repurposed antibiotics. Yet these therapies are often ineffective and associated with significant adverse events. To address this challenge, research efforts are underway to develop new antibiotics and regimens. During the preclinical phase of treatment development, experimental agents require testing and comparison alongside positive controls that are known agents with clinical history. As there are no FDA approved treatments for this indication, here, we have considered repurposed antibiotics currently included in the recommendation for treating Mab disease as candidates for selection of an ideal standard comparator that can serve as a positive control in preclinical studies. Clofazimine meets the criteria for an ideal positive control as it can be administered via the least invasive route, requires only once-daily dosing, is well tolerated, and is widely available in high purity from independent sources. Using a mouse model of pulmonary Mab disease, we assessed for ideal dosages of clofazimine in C3HeB/FeJ and BALB/c mice in a six-week treatment window. Clofazimine, 25 mg/kg, once daily, produced desired reduction in Mab burden in the lungs of C3HeB/FeJ and BALB/c mice. Based on these findings, we conclude that clofazimine meets the criteria for a positive control comparator in mice for use in preclinical efficacy assessments of agents for treatment of Mab pulmonary disease. Although not included in the current standard-of-care for treating Mab disease, rifabutin, 20 mg/kg, also produced desired reduction in Mab lung burden in C3HeB/FeJ mice but not in BALB/c mice. IMPORTANCE: Mycobacteroides abscessus can cause life-threatening infections in patients with chronic lung conditions. New treatments are needed as cure rate using existing drugs is low. During pre-clinical phase of treatment development, it is important to compare the efficacy of the experimental drug against existing ones with known history. Here, we demonstrate that clofazimine, one of the antibiotics repurposed for treating Mab disease, can serve as a positive control comparator for efficacy assessments of experimental drugs and regimens to treat M. abscessus disease in mice.

Current clinical practice in antibiotic treatment of Staphylococcus aureus bacteraemia: results from a survey in five European countries

OBJECTIVES

To determine clinical practice variation and identify knowledge gaps in antibiotic treatment of Staphylococcus aureus bacteraemia (SAB).

METHODS

A web-based survey with questions addressing antibiotic treatment of SAB was distributed through the ESGAP network among infectious disease specialists, clinical microbiologists and internists in Croatia, France, Greece, the Netherlands and the UK between July 2021 and November 2021.

RESULTS

A total number of 1687 respondents opened the survey link, of whom 677 (40%) answered at least one question. For MSSA and MRSA bacteraemia, 98% and 94% preferred initial monotherapy, respectively. In patients with SAB and non-removable infected prosthetic material, between 80% and 90% would use rifampicin as part of the treatment. For bone and joint infections, 65%-77% of respondents would consider oral step-down therapy, but for endovascular infections only 12%-32% would. Respondents recommended widely varying treatment durations for SAB with different foci of infection. Overall, 48% stated they used 18F-fluorodeoxyglucose positron emission tomography/CT (18F-FDG-PET/CT) to guide antibiotic treatment duration. Persistent bacteraemia was the only risk factor for complicated SAB that would prompt a majority to extend treatment from 2 to 4-6 weeks.

CONCLUSIONS

This survey in five European countries shows considerable clinical practice variation between and within countries in the antibiotic management of SAB, in particular regarding oral step-down therapy, choice of oral antibiotic agents, treatment duration and use of 18F-FDG-PET/CT. Physicians use varying criteria for treatment decisions, as evidence from clinical trials is often lacking. These areas of practice variation could be used to prioritize future studies for further improvement of SAB care.

Comparison of Sequential Dalbavancin to Standard-of-Care Treatment for Staphylococcus aureus Bloodstream Infections

Background

Dalbavancin (DAL) is a long-acting lipoglycopeptide with activity against Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA). This study investigates DAL as sequential therapy in S. aureus bloodstream infections (BSIs).

Methods

We conducted a retrospective cohort study from 2014 to 2021 comparing sequential DAL with standard-of-care therapy (SoC) for S. aureus BSI. The primary outcome was 90-day clinical failure (90-day all-cause mortality or 90-day recurrence). Secondary outcomes were incidence of acute kidney injury, creatinine phosphokinase elevations, catheter-related thrombosis, and hospital-acquired infections. Analyses were adjusted using inverse probability of treatment weighting (IPTW).

Results

Overall, 225 patients (45 DAL, 180 SoC) were included. DAL patients had a higher incidence of community-acquired infection and persons who use drugs; SoC patients had more comorbidities and a longer duration of bacteremia. MRSA incidence was similar between the DAL and SoC groups. The median length of stay was 16 days among DAL recipients compared with 24 days among SoC recipients. Central catheter placement was 17.8% compared with 57.2% in the SoC group. Ninety-day clinical failure occurred in 13.3% and 18.3% of participants in the DAL and SOC groups, respectively. In IPTW-adjusted analysis, sequential DAL was not associated with 90-day clinical failure (adjusted odds ratio, 0.94; 95% CI, 0.333–2.32).

Conclusions

This study provides preliminary evidence that select patients with S. aureus BSI treated with sequential DAL have similar clinical failure rates, with significant reductions in catheter placement and hospital length of stay compared with SoC. Further prospective evaluation is needed.

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.

Evaluation of step-down oral antibiotic therapy for uncomplicated streptococcal bloodstream infections on clinical outcomes

Background:

Despite the severity and frequency of streptococcal bloodstream infections (BSIs), the effectiveness of oral definitive therapy remains unknown. The objective of this study was to evaluate the clinical outcomes of step-down oral antibiotics for the treatment of uncomplicated streptococcal BSIs.

Methods:

In this retrospective cohort study, adult patients admitted with uncomplicated streptococcal BSI between June 2015 and June 2017 were included. Patients were excluded if they received <48 h of antibiotic therapy; therapy was started >48 h after first positive culture; had complicated infections of endocarditis, bone and joint infections, or central nervous system infections; Pitt bacteremia score (PBS) ⩾ 4; or failed to respond to effective therapy necessitating continued intravenous (IV) therapy. Patients were grouped by receipt of step-down oral antibiotic therapy (PO group) versus continued IV therapy (IV group). Outcomes included hospital length of stay (LOS), 30-day recurrence of BSI, 30-day readmission, 30-day all-cause mortality, and catheter-related or drug-related adverse events (AEs).

Results:

Of 244 patients included, 40% received step-down oral therapy (n = 98). Overall, the most common source of BSI was pneumonia (22%), followed by skin and soft tissue infections (SSTI) (18%). Severity of illness measured by intensive care unit (ICU) admission and PBS was similar. The IV group had significantly longer LOS [median 10 (interquartile range [IQR] = 5–21) versus 5 (4–6) days, p < 0.01] compared with the PO group. BSI recurrence, readmission, all-cause mortality within 30 days, and AEs were similar between the groups (p = ns).

Conclusion:

In uncomplicated streptococcal BSI, patients treated with step-down oral antibiotic therapy had significantly shorter LOS compared with continued IV therapy without compromise of clinical outcomes.

Intravenous versus Oral Step-Down for the Treatment of Staphylococcus aureus Bacteremia in a Pediatric Population

Limited data are available regarding optimal antimicrobial therapy for Staphylococcus aureus bacteremia (SAB) in pediatric patients. The purpose of this study was to assess clinical characteristics and outcomes associated with intravenous (IV) versus oral step-down treatment of pediatric SAB. This study evaluated patients aged 3 months to 18 years that received at least 72 h of inpatient treatment for SAB. The primary endpoint was 30-day readmission. Secondary endpoints included hospital length of stay and inpatient mortality. One hundred and one patients were included in this study. The median age was 7.9 years. Patients who underwent oral step-down were less likely to be immunocompromised and more likely to have community-acquired SAB from osteomyelitis or skin and soft tissue infection (SSTI). More patients in the IV therapy group had a 30-day readmission (10 (25.6%) vs. 3 (5.3%), p = 0.006). Mortality was low (5 (5%)) and not statistically different between groups. Length of stay was greater in patients receiving IV therapy only (11 vs. 7 days, p = 0.001). In this study, over half of the patients received oral step-down therapy and 30-day readmission was low for this group. Oral therapy appears to be safe and effective for patients with SAB from osteomyelitis or SSTIs.

Safety of prolonged outpatient courses of intravenous antibiotics: a prospective cohort study

OBJECTIVES

The perceived need for prolonged intravenous antibiotic courses has become a major driver behind the growth of outpatient parenteral antimicrobial therapy (OPAT) services. Several recent randomised controlled trials demonstrate non-inferiority of early switch to oral therapy and highlight the need to accurately quantify harms associated with OPAT.

METHODS

We conducted a 10-year prospective cohort study in a tertiary hospital OPAT service. Adults admitted to the service between 1^st June 2009 and 30^th June 2019 who received an intravenous antimicrobial agent were included. Adverse events (AEs) attributable to intravenous antibiotics or intravenous access were recorded in a prospectively maintained database and analysed.

RESULTS

There were 4,160 admissions (median length of stay 20 days), and a total of 88,432 patient-days of observation. 135 (3.3% of admissions) experienced at least one major AE (1.54/1,000 patient days [95%CI: 1.29 to 1.82]). The risk of a major AE peaked in the second week of OPAT admission, with acute kidney injury (43/136, 32%) and severe cytopenia (42/136, 31%) being most common. At least one minor AE occurred in 38.3% (1,592/4,160) of admissions (26.4 per 1,000 patient days [95%CI: 25.4 to 27.5]), with central venous catheter related complications accounting for 71% (1658/2338).

CONCLUSIONS

The incidence of major adverse events during long courses of intravenous antibiotics is low, peaking in week two and tailing off thereafter. These results should inform decisions concerning the choice of intravenous versus oral antimicrobials.

How I manage a patient with MRSA bacteraemia

BACKGROUND

Staphylococcus aureus bloodstream infections are common and associated with a high mortality of 15-25%. Methicillin-resistant S. aureus (MRSA) bloodstream infection accounts for 10-40% of cases, and has an even higher mortality. Despite being the 'bread and butter' of clinical infectious diseases practice, robust evidence to guide optimal management is often lacking and there is wide variation in practice.

OBJECTIVES

To provide a real-world example of a case of MRSA bacteraemia and the thought processes of the authors as key management decision points are reached.

SOURCES

The discussion is based on recent literature searches of relevant topics. In making recommendations, randomized clinical trial data have been prioritized and highlighted, and where these are not available recommendations are based on the experience and opinions of the authors.

CONTENT

For a patient with MRSA bacteraemia and a primary bone and joint infection the following points are discussed: empirical antibiotic choice for suspected S. aureus bacteraemia; directed antibiotic choice for MRSA; monitoring and dosing of vancomycin; the role of combination therapy when bacteraemia is persistent; and the duration of therapy and role of switching to oral antibiotics.

IMPLICATIONS

While broad principles of aggressive source control and appropriate choice and duration of antibiotics are important, the heterogeneity of S. aureus bacteraemia means that a tailored rather than algorithmic approach to management is often required. Further randomized controlled trials are needed to strengthen the evidence base for the management of MRSA bacteraemia.

"Mortality in Staphylococcus aureus bacteraemia remains high despite adherence to quality indicators: secondary analysis of a prospective cohort study"

OBJECTIVES

To evaluate the association between compliance with previously published quality indicators (QIs) for the management of Staphylococcus aureus bacteraemia (SAB) and 30-day mortality.

METHODS

We conducted a post hoc analysis of all adult patients with SAB who were hospitalized at a Spanish university hospital between 2013 and 2018. We evaluated the compliance with 7 QIs of SAB management (i.e., Infectious Diseases consultation, follow-up blood cultures, early source control, echocardiography, early cloxacillin or cefazolin, vancomycin monitoring, and appropriate treatment duration). The QIs compliance rate was considered good if ≥75% of the QIs recommended in each patient were performed. We studied the impact of different risk factors (including QIs compliance) on 30-day all-cause mortality adjusting by multivariable modeling and propensity-matched analysis.

RESULTS

We included 441 patients with SAB. The QIs compliance rate was ≥75% in 361 patients (81.9%). A total of 95 patients (21.5%) died within 30 days after the index blood culture. In the multivariable model, the variables associated with 30-day mortality were: age (OR, 1.1; 95% CI, 1.0-1.1), Charlson comorbidity index (OR, 1.2; 95% CI, 1.1-1.4), persistent bacteraemia >72 h (OR, 6.0; 95% CI, 3.2-11.5), infective endocarditis (OR, 2.8; 95% CI, 1.2-6.7), and SAB of unknown source (OR, 3.3; 95% CI, 1.5-7.1). We did not find an association between a global QIs compliance rate of ≥75% or any individual QI with 30-day mortality.

CONCLUSIONS

SAB 30-day mortality remains high despite good adherence to previously published QIs for the management of SAB. Future research should focus on additional factors to further improve SAB-related mortality.

Applying the Infectious Diseases Literature to People who Inject Drugs

People who inject drugs (PWID) presenting with injection drug use-associated infections are an understudied population excluded from most prospective infectious disease (ID) clinical trials. Careful application of the existing ID literature to PWID must consider their unique medical, psychological, and social challenges. Identification and treatment of the underlying substance use disorder are key underpinnings to any successful ID intervention.

Comparison of linezolid step-down therapy to standard parenteral therapy in methicillin-resistant Staphylococcus aureus bloodstream infections

Data supporting oral step-down therapy in methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection (BSI) are sparse; linezolid offers potential in this setting. This study aimed to determine the effectiveness and safety of oral step-down linezolid compared with standard parenteral therapy (SPT) in MRSA-BSI. This was a retrospective cohort performed in adults receiving step-down/outpatient linezolid or SPT (vancomycin, daptomycin) for MRSA-BSI from 2011-2019. Primary outcome was 90-day infection-related re-admission (IRR) from clinical worsening/relapse or infection recurrence. 215 patients included (54 linezolid, 161 SPT). Infection sources were skin (34%), bone/joint (15%), endocarditis (13%), other (32%), multiple (6%). Patients receiving SPT more commonly had complicated bacteraemia (72% vs. 41%; P < 0.0001) and metastatic foci (45% vs. 20%; P = 0.001). 90-day IRR occurred in 17% and 26% of linezolid and SPT groups, respectively (P = 0.159). When accounting for disease severity, linezolid use was not independently associated with 90-day IRR (adjOR, 1.0, 95% CI 0.24-4.3; P = 0.986). There were no differences in all-cause 90-day mortality (4% vs. 6%, P = 0.487) or overall incidence of drug-related adverse events (AEs) (17% vs. 16%; P = 0.843) between the groups. More patients in the SPT group developed an AE requiring re-hospitalisation (12% vs. 2%; P = 0.024), most commonly line-related complications. Oral step-down linezolid demonstrated similar clinical and safety outcomes compared with SPT for MRSA-BSI, except linezolid was associated with fewer AEs requiring re-hospitalisation. Additional research is needed exploring step-down linezolid in MRSA-BSI, particularly in patients requiring shorter durations of outpatient therapy.

Bacteremia due to Methicillin-Resistant Staphylococcus aureus: An Update on New Therapeutic Approaches

Vancomycin and daptomycin are options for the initial treatment of patients with methicillin-resistant Staphylococcus aureus (MRSA) bacteremia. Treatment options for persistent MRSA bacteremia or bacteremia due to vancomycin-intermediate or vancomycin-resistant strains include daptomycin, ceftaroline, and combination therapies. There is a critical need for high-level evidence from clinical trials to allow optimally informed decisions in the treatment of MRSA bacteremia.

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.

New Answers for Old Questions in the Treatment of Severe Infections from Injection Drug Use

Hospitalists are increasingly responsible for the management of infectious consequences of opioid use disorder (OUD), including increasing rates of hospitalization for injection drug use (IDU)-associated infective endocarditis, osteomyelitis, and soft tissue infections. Management of IDU-associated infections poses unique challenges: symptoms of the underlying addiction can interfere with care plans, patients often have difficult psychosocial circumstances in addition to their addiction, and they are often stigmatized by the healthcare system. Although there are few randomized trial data to support one particular approach to management, the literature suggests that successful treatment of IDU-associated infections requires appropriate antimicrobial and surgical interventions in addition to acknowledgment and treatment of the underlying OUD. In this narrative review, the best available evidence is used to answer several of the most commonly encountered questions in the management of IDU-associated infections. These data are used to develop a framework for hospitalists to approach the care of patients with IDU-associated infections.

Significant Publications on Infectious Diseases Pharmacotherapy in 2019

PURPOSE

To provide a summary of the most prominent peer-reviewed infectious diseases (ID) pharmacotherapy and Human Immunodeficiency Virus (HIV)-related articles published in 2019.

SUMMARY

Houston Infectious Diseases Network (HIDN) members were asked to nominate articles that they believed were most influential within the ID and HIV pharmacotherapy science communities. A total of 48 general ID and 6 HIV-related articles were nominated. Following nominations, an online survey was distributed via e-mail to Society of Infectious Diseases Pharmacists (SIDP) members, with a total of 156 and 54 members voting for general ID and HIV-related articles, respectively. The results of this survey were ranked to determine the top 10 general ID and top HIV articles. The top articles were then summarized by HIDN members, including residents, fellows, and clinical pharmacists.

CONCLUSION

This review covers many of the most influential ID articles published in 2019, including 3 practice guideline updates. Due to the high rate of ID literature published each year, this review continues to help summarize these articles for the ID community, allowing clinicians to remain up-to-date on practice-changing publications in ID and HIV pharmacotherapy.

Clinical Utility of Lefamulin: If Not Now, When?

Purpose of Review

The looming threat of antimicrobial resistance requires robust stewardship and new developments in infectious diseases pharmacotherapy. This review discusses the pertinent spectrum and clinical data of lefamulin (Xenleta®), with a focus on potential real-world use.

Recent Findings

Lefamulin is a novel pleuromutilin antibiotic that obtained Food and Drug Administration labeling for community-acquired bacterial pneumonia (CABP) in 2019. Lefamulin is available in both intravenous and oral formulations, and it inhibits bacterial protein synthesis inhibition through interactive binding to unique sites of the peptidyl transferase center of the 50s bacterial ribosome subunit. Resistance, including cross-resistance with other antibiotics, is infrequent. Lefamulin demonstrates activity against most Gram-positive pathogens and other organisms commonly associated with CABP, i.e., Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, Legionella pneumophila, and Chlamydophila pneumoniae. Lefamulin may also be an option for serious public health threats like methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus faecium, and multi-drug-resistant organisms associated with sexually transmitted infections, e.g., Neisseria gonorrhoeae, Mycoplasma genitalium. Lefamulin lacks activity against Pseudomonas aeruginosa, Acinetobacter baumannii, Enterobacterales, most anaerobes, and E. faecalis. In Phase III trials, lefamulin monotherapy was non-inferior to moxifloxacin with or without linezolid for CABP.

Summary

Lefamulin is a well-tolerated agent with a unique mechanism, availability in both IV and PO formulations, and it has been rigorously studied for safety and efficacy for CABP.

Early Oral Antibiotic Switch for Staphylococcus aureus Bacteremia: Many Are Called, but Few Are Chosen

Staphylococcus aureus bacteremia (SAB) is a complicated, high-risk disease. For selected low-risk SAB, the role of oral antibiotic stepdown therapy is unknown. Bupha-Intr et al. report a retrospective cohort of low-risk SAB patients who did well with a short duration of intravenous antibiotics, followed by an additional ∼10 days of oral antibiotics, primarily using beta-lactams. Prospective trials will help further define the efficacy of this approach.

Efficacy of Early Oral Switch with β-Lactams for Low-Risk Staphylococcus aureus Bacteremia

The aim of this study was to assess the safety of early oral switch (EOS) prior to 14 days for low-risk Staphylococcus aureus bacteremia (LR-SAB), which is the primary treatment strategy used at our institution. The usual recommended therapy is 14 days of intravenous (i.v.) antibiotics. All patients with SAB at our hospital were identified between 1 January 2014 and 31 December 2018. Those meeting low-risk criteria (health care-associated, no evidence of deep infection or demonstrated involvement of prosthetic material, and no further positive blood cultures after 72 h) were included in the study. The primary outcome was occurrence of a SAB-related complication within 90 days. There were 469 SAB episodes during the study period, 100 (21%) of whom met inclusion criteria. EOS was performed in 84 patients. In this group, line infection was the source in 79%, methicillin-susceptible S. aureus caused 95% of SABs and 74% of patients received i.v. flucloxacillin. The median durations of i.v. and oral antibiotics in the EOS group were 5 days (interquartile range [IQR], 4 to 6) and 10 days (IQR, 9 to 14), respectively. A total of 71% of patients received flucloxacillin as their EOS agent. Overall, 86% of oral step-down therapy was with beta-lactams. One patient (1%) undergoing EOS had SAB relapse within 90 days. No deaths attributable to SAB occurred within 90 days. In this low-MRSA-prevalence LR-SAB cohort, EOS was associated with a low incidence of SAB-related complications. This was achieved with oral beta-lactam therapy in most patients. Larger prospective studies are needed to confirm these findings.

A Narrative Review of Early Oral Stepdown Therapy for the Treatment of Uncomplicated Staphylococcus aureus Bacteremia: Yay or Nay?

Historically, intravenous (IV) antibiotics have been the cornerstone of treatment for uncomplicated Staphylococcus aureus bacteremia (SAB). However, IV antibiotics are expensive, increase the rates of hospital readmission, and can be associated with catheter-related complications. As a result, the potential role of oral antibiotics in the treatment of uncomplicated SAB has become a subject of interest. This narrative review article aims to summarize key arguments for and against the use of oral antibiotics to complete treatment of uncomplicated SAB and evaluates the available evidence for specific oral regimens. We conclude that evidence suggests that oral step-down therapy can be an alternative for select patients who meet the criteria for uncomplicated SAB and will comply with medical treatment and outpatient follow-up. Of the currently studied regimens discussed in this article, linezolid has the most support, followed by fluoroquinolone plus rifampin.

Linezolid use in German acute care hospitals: results from two consecutive national point prevalence surveys

Background

Linezolid belongs to a reserve group of antibiotics. In recent years, reports on linezolid resistance in gram-positive cocci have become more frequent. Overuse of linezolid is a relevant factor for resistance development. The objective of this study was to describe current prescription practices of linezolid in German hospitals and identify targets for antimicrobial stewardship interventions.

Methods

We analyzed all linezolid prescriptions from the datasets of the consecutive national point prevalence surveys performed in German hospitals in 2011 and 2016. In both surveys, data on healthcare-associated infections and antimicrobial use were collected following the methodology of the European Centre for Disease Prevention and Control.

Results

Overall, the percentage of linezolid among all documented antimicrobials increased significantly from 2011 to 2016 (p < 0.01). In 2011, 0.3% (119 of 41,539) patients received linezolid, in 2016 this proportion was significantly higher (0.4%; 255 of 64,412 patients; p < 0.01). In 2016, intensive care units (ICUs) were the wards most frequently prescribing linezolid. The largest proportion of patients receiving linezolid were non-ICU patients. Roughly 38% of linezolid prescriptions were for treatment of skin/soft tissue and respiratory tract infections. In 2016, linezolid was administered parenterally in 70% (n = 179) of cases. Multivariable analysis showed that the ward specialty ICU posed an independent risk factor, while Northern and Southwestern regions in Germany were independent protective factors for a high rate of linezolid prescriptions.

Conclusions

In conclusion, we detected potentials for improving linezolid prescription practices in German hospitals. Given the emergence of linezolid resistance, optimization of linezolid use must be a target of future antimicrobial stewardship activities.

Practice Patterns of Infectious Diseases Physicians in Transitioning From Intravenous to Oral Therapy in Patients With Bacteremia

Background

Bacteremia in adult patients has traditionally been treated with extended courses of intravenous antibiotics. Data on the use of (or rapid transition to) oral therapy are limited.

Methods

Adult infectious disease physicians participating in the Infectious Diseases Society of America Emerging Infections Network (EIN) were surveyed regarding their use of oral antibiotics in patients with bacteremia. Respondents were asked to assume that patients were hemodynamically stable, recovered bacteria were susceptible to potential antibiotics, adequate source control had been achieved, and patients had adequate gastrointestinal absorption. Variables of specific bacteria, oral agent, and associated infection were included.

Results

A total of 655 (50%) of 1321 EIN participants responded. Under certain conditions, 88% would transition patients with Gram-negative bacteremia to complete a course of therapy with oral antibiotics; 71% would transition patients with Gram-positive bacteremia to oral agents. Only 78 (12%) respondents would not treat any bacteremic patient with oral agents. Most respondents (≥75%) were comfortable treating infections secondary to Enterobacteriaceae, Salmonella, Pseudomonas, Stenotrophomonas, Streptococcus pneumoniae, and β-hemolytic streptococci with oral agents. Fewer than 20% endorsed use of oral antibiotics for Staphylococcus aureus or in cases of endocarditis. Fluoroquinolones and trimethoprim-sulfamethoxazole were the preferred agents in Gram-negative bacteremia; linezolid and β-lactams were the preferred agents in Gram-positive bacteremia.

Conclusions

In select circumstances, the majority of respondents would transition patients to oral antibiotics, in both Gram-negative and Gram-positive bacteremia. Most agreed with the use of oral agents in Gram-negative bacteremia caused by Enterobacteriaceae, but they would not use oral agents for Gram-positive bacteremia caused by S aureus or in endocarditis.

Long-Acting Lipoglycopeptides: "Lineless Antibiotics" for Serious Infections in Persons Who Use Drugs

Background

Injection drug use is associated with serious infections. Due to challenges with medical management of addiction, relapses and additional infections are common. Persons who use drugs (PWUD) are more likely to leave against medical advice before completing treatment, which could result in treatment failure. Prolonged intravenous (IV) antimicrobial therapy in PWUD may be complicated by concern for IV catheter misuse, sometimes requiring prolonged hospitalization. Ideal alternatives would provide the following: (1) high success rate; (2) reduced rate of medical complications; (3) improved safety profiles; and (4) improved cost-effectiveness. Long-acting lipoglycopeptides present such opportunity for treatment of serious Gram-positive infections.

Methods

We performed a system-wide, retrospective analysis of adults admitted to University of Colorado Health from September 2015 to June 2018 and treated with dalbavancin or oritavancin based on clinical judgment of their treating physicians.

Results

Fifty-six patients met inclusion criteria (17 PWUD vs 39 non-PWUD). The PWUD group were younger, healthier by Charlson comorbidity index, more likely insured by Medicaid, and admitted for conditions requiring longer treatment. Ten patients were lost to follow-up. Of the patients with follow-up, clinical failure was met in 1 PWUD patient (6%) and 6 non-PWUD patients (15%) (P = .413). The median hospital length-of-stay reduction was 20 days (interquartile range [IQR], 10–30 days) in PWUD vs 11 days (IQR, 9–14 days) in non-PWUD; P = .133. Estimated median savings were $40 455.08 (IQR, $20 900.00–$62 700.00) in PWUD vs $19 555.08 (IQR, $15 375.08–$23 735.08) in non-PWUD; P = .065.

Conclusions

Long-acting lipoglycopeptides may be equally effective as standard-of-care, present a safety advantage, and secure earlier discharge and significant cost-savings.