Exebacase in Addition to Standard-of-Care Antibiotics for Staphylococcus aureus Bloodstream Infections and Right-Sided Infective Endocarditis: A Phase 3, Superiority-Design, Placebo-Controlled, Randomized Clinical Trial (DISRUPT).

BACKGROUND: Novel treatments are needed for Staphylococcus aureus bacteremia, particularly for methicillin-resistant S. aureus (MRSA). Exebacase is a first-in-class antistaphylococcal lysin that is rapidly bactericidal and synergizes with antibiotics. METHODS: In DISRUPT, a superiority-design phase 3 study, patients with S. aureus bacteremia/endocarditis were randomly assigned to receive a single dose of IV exebacase or placebo in addition to standard-of-care antibiotics. The primary efficacy outcome was clinical response at Day 14 in the MRSA population. RESULTS: A total of 259 patients were randomized before the study was stopped for futility based on the recommendation of the unblinded Data Safety Monitoring Board. Clinical response rates at Day 14 in the MRSA population (n = 97) were 50.0% (exebacase + antibiotics; 32/64) vs. 60.6% (antibiotics alone; 20/33) (P = 0.392). Overall, rates of adverse events were similar across groups. No adverse events of hypersensitivity related to exebacase were reported. CONCLUSIONS: Exebacase + antibiotics failed to improve clinical response at Day 14 in patients with MRSA bacteremia/endocarditis. This result was unexpected based on phase 2 data that established proof-of-concept for exebacase + antibiotics in patients with MRSA bacteremia/endocarditis. In the antibiotics alone group, the clinical response rate was higher than that seen in phase 2. Heterogeneity within the study population and a relatively small sample size in either the phase 2 or phase 3 studies may have increased the probability of imbalances in the multiple components of Day 14 clinical outcome. This study provides lessons for future superiority studies in S. aureus bacteremia/endocarditis.

Effectiveness of a Messenger RNA Vaccine Booster Dose Against Coronavirus Disease 2019 Among US Healthcare Personnel, October 2021-July 2022.

Background: Protection against symptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (coronavirus disease 2019 [COVID-19]) can limit transmission and the risk of post-COVID conditions, and is particularly important among healthcare personnel. However, lower vaccine effectiveness (VE) has been reported since predominance of the Omicron SARS-CoV-2 variant. Methods: We evaluated the VE of a monovalent messenger RNA (mRNA) booster dose against COVID-19 from October 2021 to June 2022 among US healthcare personnel. After matching case-participants with COVID-19 to control-participants by 2-week period and site, we used conditional logistic regression to estimate the VE of a booster dose compared with completing only 2 mRNA doses >150 days previously, adjusted for multiple covariates. Results: Among 3279 case-participants and 3998 control-participants who had completed 2 mRNA doses, we estimated that the VE of a booster dose against COVID-19 declined from 86% (95% confidence interval, 81%-90%) during Delta predominance to 65% (58%-70%) during Omicron predominance. During Omicron predominance, VE declined from 73% (95% confidence interval, 67%-79%) 14-60 days after the booster dose, to 32% (4%-52%) ≥120 days after a booster dose. We found that VE was similar by age group, presence of underlying health conditions, and pregnancy status on the test date, as well as among immunocompromised participants. Conclusions: A booster dose conferred substantial protection against COVID-19 among healthcare personnel. However, VE was lower during Omicron predominance, and waning effectiveness was observed 4 months after booster dose receipt during this period. Our findings support recommendations to stay up to date on recommended doses of COVID-19 vaccines for all those eligible.

Analysis of Outcomes Associated With Outpatient Management of Nonoperatively Treated Patients With Appendicitis.

Importance: In the Comparison of Outcomes of Antibiotic Drugs and Appendectomy (CODA) trial, which found antibiotics to be noninferior, approximately half of participants randomized to receive antibiotics had outpatient management with hospital discharge within 24 hours. If outpatient management is safe, it could increase convenience and decrease health care use and costs. Objective: To assess the use and safety of outpatient management of acute appendicitis. Design, Setting, and Participants: This cohort study, which is a secondary analysis of the CODA trial, included 776 adults with imaging-confirmed appendicitis who received antibiotics at 25 US hospitals from May 1, 2016, to February 28, 2020. Exposures: Participants randomized to antibiotics (intravenous then oral) could be discharged from the emergency department based on clinician judgment and prespecified criteria (hemodynamically stable, afebrile, oral intake tolerated, pain controlled, and follow-up confirmed). Outpatient management and hospitalization were defined as discharge within or after 24 hours, respectively. Main Outcomes and Measures: Outcomes compared among patients receiving outpatient vs inpatient care included serious adverse events (SAEs), appendectomies, health care encounters, satisfaction, missed workdays at 7 days, and EuroQol 5-dimension (EQ-5D) score at 30 days. In addition, appendectomy incidence among outpatients and inpatients, unadjusted and adjusted for illness severity, was compared. Results: Among 776 antibiotic-randomized participants, 42 (5.4%) underwent appendectomy within 24 hours and 8 (1.0%) did not receive their first antibiotic dose within 24 hours, leaving 726 (93.6%) comprising the study population (median age, 36 years; range, 18-86 years; 462 [63.6%] male; 437 [60.2%] White). Of these participants, 335 (46.1%; site range, 0-89.2%) were discharged within 24 hours, and 391 (53.9%) were discharged after 24 hours. Over 7 days, SAEs occurred in 0.9 (95% CI, 0.2-2.6) per 100 outpatients and 1.3 (95% CI, 0.4-2.9) per 100 inpatients; in the appendicolith subgroup, SAEs occurred in 2.3 (95% CI, 0.3-8.2) per 100 outpatients vs 2.8 (95% CI, 0.6-7.9) per 100 inpatients. During this period, appendectomy occurred in 9.9% (95% CI, 6.9%-13.7%) of outpatients and 14.1% (95% CI, 10.8%-18.0%) of inpatients; adjusted analysis demonstrated a similar difference in incidence (-4.0 percentage points; 95% CI, -8.7 to 0.6). At 30 days, appendectomies occurred in 12.6% (95% CI, 9.1%-16.7%) of outpatients and 19.0% (95% CI, 15.1%-23.4%) of inpatients. Outpatients missed fewer workdays (2.6 days; 95% CI, 2.3-2.9 days) than did inpatients (3.8 days; 95% CI, 3.4-4.3 days) and had similar frequency of return health care visits and high satisfaction and EQ-5D scores. Conclusions and Relevance: These findings support that outpatient antibiotic management is safe for selected adults with acute appendicitis, with no greater risk of complications or appendectomy than hospital care, and should be included in shared decision-making discussions of patient preferences for outcomes associated with nonoperative and operative care. Trial Registration: ClinicalTrials.gov Identifier: NCT02800785.

A plain language summary of how lefamulin alone can be used to treat pneumonia caught outside of the hospital due to common bacterial causes, including drug-resistant bacteria.

WHAT IS THIS SUMMARY ABOUT?: Bacterial pneumonia is an infection of the lung caused by bacteria that is potentially deadly, costly, and affects millions of people worldwide every year. Treatment is becoming more challenging-many current treatments no longer work well because some strains of bacteria that cause pneumonia have become resistant to current antibiotics. Many of the antibiotics that do still work have undesirable side effects. Therefore, new antibiotics that work differently are needed to treat bacterial pneumonia. Lefamulin (brand name, Xenleta®) is an antibiotic that was approved to treat bacterial pneumonia caught outside a hospital (also called community-acquired bacterial pneumonia, or CABP) based on results of two clinical studies. In both studies, participants started treatment with lefamulin before the type of bacteria causing the infection was known. Lefamulin was well tolerated and worked well in 5 to 7 days to kill the bacteria causing the infection and to improve symptoms in almost all participants with CABP. WHAT WERE THE RESULTS?: After the studies were completed, the researchers looked back at what kinds of bacteria were identified from the study participants. Lefamulin worked well to kill bacteria and to improve CABP symptoms for most kinds of infecting bacteria, including bacteria resistant to many current antibiotics. WHAT DO THE RESULTS MEAN?: These results suggest that lefamulin, by itself, provides a much-needed treatment option for CABP that covers most of the key bacteria causing this infection.

Efficacy and Safety of Omadacycline Versus Linezolid in Acute Bacterial Skin and Skin Structure Infections in Persons Who Inject Drugs.

INTRODUCTION: Acute bacterial skin and skin structure infections (ABSSSI) represent one of the most common reasons for emergency department visits, and are frequent complications of intravenous drug use in persons who inject drugs (PWID). This study examined the efficacy and safety of omadacycline, versus linezolid, in PWID and persons who do not inject drugs, in the Phase 3 Omadacycline in Acute Skin and Skin Structure Infection (OASIS-1, OASIS-2) studies. METHODS: Eligible participants were aged ≥ 18 years with qualifying skin infections: wound infection, cellulitis, erysipelas, or major abscess. The primary efficacy endpoint was early clinical response (ECR) in the modified intent-to-treat (mITT) population, defined as survival with ≥ 20% reduction in lesion size at 48-72 h after the first dose of omadacycline or linezolid. Key secondary endpoints included investigator-assessed clinical response at the post-treatment evaluation (PTE) in the mITT and clinical per-protocol populations, and clinical response at PTE in the micro-mITT population. Safety was assessed based on adverse events (AEs) and standard clinical laboratory tests. Efficacy endpoints of clinical response at ECR and PTE were analyzed for the mITT and clinically evaluable (CE) PTE populations. RESULTS: In total, 1380 patients (822 PWID, 558 non-PWID) were included in this secondary analysis. Wound infections were reported more frequently in the PWID subgroup (72.8%) at baseline; cellulitis or erysipelas (43.9%) and major abscess (37.4%) were the most frequently reported baseline infections in the non-PWID subgroup. Clinical success rates at ECR and PTE in the mITT population, and at PTE in the CE population, were high for patients receiving omadacycline or linezolid. Severe or serious treatment-emergent AEs (TEAEs), and TEAEs leading to discontinuation, were infrequent. CONCLUSION: This subgroup analysis showed that omadacycline was effective and well tolerated, regardless of PWID status.

Pooled microbiological findings and efficacy outcomes by pathogen in adults with community-acquired bacterial pneumonia from the Lefamulin Evaluation Against Pneumonia (LEAP) 1 and LEAP 2 phase 3 trials of lefamulin versus moxifloxacin.

OBJECTIVES: Lefamulin, a pleuromutilin antibiotic approved for community-acquired bacterial pneumonia (CABP), was evaluated for microbiological efficacy in a prespecified pooled analysis of LEAP 1 and 2 phase 3 clinical trial data in patients with CABP. METHODS: In LEAP 1, adults (PORT risk class III‒V) received intravenous (IV) lefamulin 150 mg every 12 h (q12h) for 5‒7 days or moxifloxacin 400 mg every 24 h (q24h) for 7 days, with optional IV-to-oral switch. In LEAP 2, adults (PORT II‒IV) received oral lefamulin 600 mg q12h for 5 days or moxifloxacin 400 mg q24h for 7 days. Primary outcomes were early clinical response (ECR) at 96 ± 24 h after treatment start and investigator assessment of clinical response (IACR) 5‒10 days after the last dose. Secondary outcomes included ECR and IACR in patients with a baseline CABP pathogen (detected via culture, urinary antigen testing, serology and/or real-time PCR). RESULTS: Baseline CABP pathogens were detected in 709/1289 patients (55.0%; microbiological intention-to-treat population). The most frequently identified pathogens were Streptococcus pneumoniae (61.9% of patients) and Haemophilus influenzae (29.9%); 25.1% had atypical pathogens and 33.1% had polymicrobial infections. Pathogens were identified most frequently by PCR from sputum, followed by culture from respiratory specimens. In patients with baseline CABP pathogens, ECR rates were 89.3% (lefamulin) and 93.0% (moxifloxacin); IACR success rates were 83.2% and 86.7%, respectively. Results were consistent across CABP pathogens, including drug-resistant isolates and polymicrobial infections. CONCLUSION: Lefamulin is a valuable IV and oral monotherapy option for empirical and directed CABP treatment in adults.

Lefamulin in Patients with Community-Acquired Bacterial Pneumonia Caused by Atypical Respiratory Pathogens: Pooled Results from Two Phase 3 Trials.

Lefamulin was the first systemic pleuromutilin antibiotic approved for intravenous and oral use in adults with community-acquired bacterial pneumonia based on two phase 3 trials (Lefamulin Evaluation Against Pneumonia [LEAP]-1 and LEAP-2). This pooled analysis evaluated lefamulin efficacy and safety in adults with community-acquired bacterial pneumonia caused by atypical pathogens (Mycoplasma pneumoniae, Legionella pneumophila, and Chlamydia pneumoniae). In LEAP-1, participants received intravenous lefamulin 150 mg every 12 h for 5-7 days or moxifloxacin 400 mg every 24 h for 7 days, with optional intravenous-to-oral switch. In LEAP-2, participants received oral lefamulin 600 mg every 12 h for 5 days or moxifloxacin 400 mg every 24 h for 7 days. Primary outcomes were early clinical response at 96 ± 24 h after first dose and investigator assessment of clinical response at test of cure (5-10 days after last dose). Atypical pathogens were identified in 25.0% (91/364) of lefamulin-treated patients and 25.2% (87/345) of moxifloxacin-treated patients; most were identified by ≥1 standard diagnostic modality (M. pneumoniae 71.2% [52/73]; L. pneumophila 96.9% [63/65]; C. pneumoniae 79.3% [46/58]); the most common standard diagnostic modality was serology. In terms of disease severity, more than 90% of patients had CURB-65 (confusion of new onset, blood urea nitrogen > 19 mg/dL, respiratory rate ≥ 30 breaths/min, blood pressure <90 mm Hg systolic or ≤60 mm Hg diastolic, and age ≥ 65 years) scores of 0-2; approximately 50% of patients had PORT (Pneumonia Outcomes Research Team) risk class of III, and the remaining patients were more likely to have PORT risk class of II or IV versus V. In patients with atypical pathogens, early clinical response (lefamulin 84.4-96.6%; moxifloxacin 90.3-96.8%) and investigator assessment of clinical response at test of cure (lefamulin 74.1-89.7%; moxifloxacin 74.2-97.1%) were high and similar between arms. Treatment-emergent adverse event rates were similar in the lefamulin (34.1% [31/91]) and moxifloxacin (32.2% [28/87]) groups. Limitations to this analysis include its post hoc nature, the small numbers of patients infected with atypical pathogens, the possibility of PCR-based diagnostic methods to identify non-etiologically relevant pathogens, and the possibility that these findings may not be generalizable to all patients. Lefamulin as short-course empiric monotherapy, including 5-day oral therapy, was well tolerated in adults with community-acquired bacterial pneumonia and demonstrated high clinical response rates against atypical pathogens.

Front-Line Emergency Department Clinician Acceptability and Use of a Prototype Real-Time Cloud-Based Influenza Surveillance System.

Objectives: To assess emergency department (ED) clinicians' perceptions of a novel real-time influenza surveillance system using a pre- and post-implementation structured survey. Methods: We created and implemented a laboratory-based real-time influenza surveillance system at two EDs at the beginning of the 2013-2014 influenza season. Patients with acute respiratory illness were tested for influenza using rapid PCR-based Cepheid Xpert Flu assay. Results were instantaneously uploaded to a cloud-based data aggregation system made available to clinicians via a web-based dashboard. Clinicians received bimonthly email updates summating year-to-date results. Clinicians were surveyed prior to, and after the influenza season, to assess their views regarding acceptability and utility of the surveillance system data which were shared via dashboard and email updates. Results: The pre-implementation survey revealed that the majority (82%) of the 151 ED clinicians responded that they "sporadically" or "don't," actively seek influenza-related information during the season. However, most (75%) reported that they would find additional information regarding influenza prevalence useful. Following implementation, there was an overall increase in the frequency of clinician self-reporting increased access to surveillance information from 50 to 63%, with the majority (75%) indicating that the surveillance emails impacted their general awareness of influenza. Clinicians reported that the additional real-time surveillance data impacted their testing (65%) and treatment (51%) practices. Conclusions: The majority of ED clinicians found surveillance data useful and indicated the additional information impacted their clinical practice. Accurate and timely surveillance information, distributed in a provider-friendly format could impact ED clinician management of patients with suspected influenza.

Effectiveness of mRNA Covid-19 Vaccine among U.S. Health Care Personnel.

BACKGROUND: The prioritization of U.S. health care personnel for early receipt of messenger RNA (mRNA) vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (Covid-19), allowed for the evaluation of the effectiveness of these new vaccines in a real-world setting. METHODS: We conducted a test-negative case-control study involving health care personnel across 25 U.S. states. Cases were defined on the basis of a positive polymerase-chain-reaction (PCR) or antigen-based test for SARS-CoV-2 and at least one Covid-19-like symptom. Controls were defined on the basis of a negative PCR test for SARS-CoV-2, regardless of symptoms, and were matched to cases according to the week of the test date and site. Using conditional logistic regression with adjustment for age, race and ethnic group, underlying conditions, and exposures to persons with Covid-19, we estimated vaccine effectiveness for partial vaccination (assessed 14 days after receipt of the first dose through 6 days after receipt of the second dose) and complete vaccination (assessed ≥7 days after receipt of the second dose). RESULTS: The study included 1482 case participants and 3449 control participants. Vaccine effectiveness for partial vaccination was 77.6% (95% confidence interval [CI], 70.9 to 82.7) with the BNT162b2 vaccine (Pfizer-BioNTech) and 88.9% (95% CI, 78.7 to 94.2) with the mRNA-1273 vaccine (Moderna); for complete vaccination, vaccine effectiveness was 88.8% (95% CI, 84.6 to 91.8) and 96.3% (95% CI, 91.3 to 98.4), respectively. Vaccine effectiveness was similar in subgroups defined according to age (<50 years or ≥50 years), race and ethnic group, presence of underlying conditions, and level of patient contact. Estimates of vaccine effectiveness were lower during weeks 9 through 14 than during weeks 3 through 8 after receipt of the second dose, but confidence intervals overlapped widely. CONCLUSIONS: The BNT162b2 and mRNA-1273 vaccines were highly effective under real-world conditions in preventing symptomatic Covid-19 in health care personnel, including those at risk for severe Covid-19 and those in racial and ethnic groups that have been disproportionately affected by the pandemic. (Funded by the Centers for Disease Control and Prevention.).

Interim Estimates of Vaccine Effectiveness of Pfizer-BioNTech and Moderna COVID-19 Vaccines Among Health Care Personnel - 33 U.S. Sites, January-March 2021.

Throughout the COVID-19 pandemic, health care personnel (HCP) have been at high risk for exposure to SARS-CoV-2, the virus that causes COVID-19, through patient interactions and community exposure (1). The Advisory Committee on Immunization Practices recommended prioritization of HCP for COVID-19 vaccination to maintain provision of critical services and reduce spread of infection in health care settings (2). Early distribution of two mRNA COVID-19 vaccines (Pfizer-BioNTech and Moderna) to HCP allowed assessment of the effectiveness of these vaccines in a real-world setting. A test-negative case-control study is underway to evaluate mRNA COVID-19 vaccine effectiveness (VE) against symptomatic illness among HCP at 33 U.S. sites across 25 U.S. states. Interim analyses indicated that the VE of a single dose (measured 14 days after the first dose through 6 days after the second dose) was 82% (95% confidence interval [CI] = 74%-87%), adjusted for age, race/ethnicity, and underlying medical conditions. The adjusted VE of 2 doses (measured ≥7 days after the second dose) was 94% (95% CI = 87%-97%). VE of partial (1-dose) and complete (2-dose) vaccination in this population is comparable to that reported from clinical trials and recent observational studies, supporting the effectiveness of mRNA COVID-19 vaccines against symptomatic disease in adults, with strong 2-dose protection.

Lefamulin efficacy and safety in a pooled phase 3 clinical trial population with community-acquired bacterial pneumonia and common clinical comorbidities.

BACKGROUND: Lefamulin, a first-in-class pleuromutilin antibiotic approved for intravenous and oral use in adults with community-acquired bacterial pneumonia (CABP), was noninferior to moxifloxacin in the Lefamulin Evaluation Against Pneumonia (LEAP) 1 intravenous-to-oral switch study and the LEAP 2 oral-only study. Using pooled LEAP 1/2 data, we examined lefamulin efficacy/safety overall and within subgroups of patients presenting with comorbidities typical in CABP management. METHODS: In LEAP 1, adults with CABP were randomized to receive intravenous lefamulin (150 mg every 12 h) for 5‒7 days or moxifloxacin (400 mg every 24 h) for 7 days, with optional intravenous-to-oral switch if predefined improvement criteria were met. In LEAP 2, adults with CABP were randomized to receive oral lefamulin (600 mg every 12 h) for 5 days or moxifloxacin (400 mg every 24 h) for 7 days. Both studies assessed early clinical response (ECR) at 96 ± 24 h after first study drug dose and investigator assessment of clinical response (IACR) at test-of-cure (5‒10 days after last dose). Pooled analyses of the overall population used a 10% noninferiority margin. RESULTS: Lefamulin (n = 646) was noninferior to moxifloxacin (n = 643) for ECR (89.3% vs 90.5%, respectively; difference - 1.1%; 95% CI - 4.4 to 2.2); IACR success rates at test-of-cure were similarly high (≥ 85.0%). High efficacy with both lefamulin and moxifloxacin was also demonstrated across all well-represented patient subgroups, including those with advanced age, diabetes mellitus, a history of cardiovascular diseases (e.g., hypertension, congestive heart failure, or arrhythmia) or chronic lung diseases (e.g., asthma or chronic obstructive pulmonary disease), elevated liver enzymes, or mild-to-moderate renal dysfunction. No new safety signals were identified. CONCLUSIONS: Lefamulin may provide a valuable intravenous/oral monotherapy alternative to fluoroquinolones or macrolides for empiric treatment of patients with CABP, including cases of patients at risk for poor outcomes due to age or various comorbidities. TRIAL REGISTRATION: ClinicalTrials.gov LEAP 1 (NCT02559310; Registration Date: 24/09/2015) and LEAP 2 (NCT02813694; Registration Date: 27/06/2016).

Oral 5-Day Lefamulin for Outpatient Management of Community-Acquired Bacterial Pneumonia: Post-hoc Analysis of the Lefamulin Evaluation Against Pneumonia (LEAP) 2 Trial.

BACKGROUND: Safe and effective oral antibiotics are needed for outpatient management of moderate to severe community-acquired bacterial pneumonia (CABP). OBJECTIVE: We describe a post-hoc analysis of adults with CABP managed as outpatients from the Lefamulin Evaluation Against Pneumonia (LEAP) 2 double-blind, noninferiority, phase 3 clinical trial. METHODS: LEAP 2 compared the efficacy and safety of oral lefamulin 600 mg every 12 h (5 days) vs. oral moxifloxacin 400 mg every 24 h (7 days) in adults (inpatients and outpatients) with Pneumonia Outcomes Research Team (PORT) risk classes II‒IV. RESULTS: Overall, 41% (151 of 368) of patients receiving lefamulin and 43% (159 of 368) of patients receiving moxifloxacin started treatment as outpatients-44% and 40%, respectively, were PORT risk class III/IV, and 21% in both groups had CURB-65 scores of 2‒3. Early clinical response (at 96 ± 24 h) and investigator assessment of clinical response success rates at test of cure (5‒10 days after last study drug dose) were high and similar in both groups among all (lefamulin, 91% vs. moxifloxacin, 89‒90%), PORT risk class III/IV (89‒91% vs. 88‒91%), and CURB-65 score 2‒3 (87‒90% vs. 82‒88%) outpatients. Few outpatients (lefamulin, 2.6%; moxifloxacin, 2.5%) discontinued the study drug because of treatment-emergent adverse events (TEAEs). No outpatient in the lefamulin group was hospitalized for a TEAE, compared with 5 patients (3%), including two deaths, in the moxifloxacin group. CONCLUSIONS: These data suggest that 5 days of oral lefamulin can be given in lieu of fluoroquinolones for outpatient treatment of adults with CABP and PORT risk class III/IV or CURB-65 scores of 2‒3.

Pathway with single-dose long-acting intravenous antibiotic reduces emergency department hospitalizations of patients with skin infections.

OBJECTIVES: Emergency department (ED) patients with serious skin and soft tissue infections (SSTIs) are often hospitalized to receive intravenous (IV) antibiotics. Appropriate patients may avoid admission following a single-dose, long-acting IV antibiotic. METHODS: We conducted a preintervention versus postintervention design trial at 11 U.S. EDs comparing hospitalization rates under usual care to those using a clinical pathway that included a single IV dalbavancin dose. We enrolled adults with cellulitis, abscess, or wound infection with an infected area of ≥75 cm2 without other indications for hospitalization. Clinical pathway participants discharged from the ED received a 24-hour follow-up telephone call and had a 48- to 72-hour in-person visit. We hypothesized that, compared to usual care, the clinical pathway would result in a significant reduction in the initial hospitalization rate. RESULTS: Of 156 and 153 participants in usual care and clinical pathway periods, median infection areas were 255.0 (interquartile range [IQR] = 150.0 to 500.0) cm2 and 289.0 (IQR = 161.3 to 555.0) cm2 , respectively. During their initial care, 60 (38.5%) usual care participants were hospitalized and 27 (17.6%) pathway participants were hospitalized (difference = 20.8 percentage points [PP], 95% confidence interval [CI] = 10.4 to 31.2 PP). Over 44 days, 70 (44.9%) usual care and 44 (28.8%) pathway participants were hospitalized (difference = 16.1 PP, 95% CI = 4.9 to 27.4 PP). CONCLUSIONS: Implementation of an ED SSTI clinical pathway for patient selection and follow-up that included use of a single-dose, long-acting IV antibiotic was associated with a significant reduction in hospitalization rate for stable patients with moderately severe infections. Registration: NCT02961764.

Emergence of Extended-Spectrum ß-Lactamase Urinary Tract Infections Among Hospitalized Emergency Department Patients in the United States.

STUDY OBJECTIVE: Enterobacteriaceae resistant to ceftriaxone, mediated through extended-spectrum ß-lactamases (ESBLs), commonly cause urinary tract infections worldwide, but have been less prevalent in North America. Current US rates are unknown. We determine Enterobacteriaceae antimicrobial resistance rates among US emergency department (ED) patients hospitalized for urinary tract infection. METHODS: We prospectively enrolled adults hospitalized for urinary tract infection from 11 geographically diverse university-affiliated hospital EDs during 2018 to 2019. Among participants with culture-confirmed infection, we evaluated prevalence of antimicrobial resistance, including that caused by ESBL-producing Enterobacteriaceae, resistance risk factors, and time to in vitro-active antibiotics. RESULTS: Of 527 total participants, 444 (84%) had cultures that grew Enterobacteriaceae; 89 of 435 participants (20.5%; 95% confidence interval 16.9% to 24.5%; 4.6% to 45.4% by site) whose isolates had confirmatory testing had bacteria that were ESBL producing. The overall prevalence of ESBL-producing Enterobacteriaceae infection among all participants with urinary tract infection was 17.2% (95% confidence interval 14.0% to 20.7%). ESBL-producing Enterobacteriaceae infection risk factors were hospital, long-term care, antibiotic exposure within 90 days, and a fluoroquinolone- or ceftriaxone-resistant isolate within 1 year. Enterobacteriaceae resistance rates for other antimicrobials were fluoroquinolone 32.3%, gentamicin 13.7%, amikacin 1.3%, and meropenem 0.3%. Ceftriaxone was the most common empirical antibiotic. In vitro-active antibiotics were not administered within 12 hours of presentation to 48 participants (53.9%) with ESBL-producing Enterobacteriaceae infection, including 17 (58.6%) with sepsis. Compared with other Enterobacteriaceae infections, ESBL infections were associated with longer time to in vitro-active treatment (17.3 versus 3.5 hours). CONCLUSION: Among adults hospitalized for urinary tract infection in many US locations, ESBL-producing Enterobacteriaceae have emerged as a common cause of infection that is often not initially treated with an in vitro-active antibiotic.

A Randomized Trial Comparing Antibiotics with Appendectomy for Appendicitis.

BACKGROUND: Antibiotic therapy has been proposed as an alternative to surgery for the treatment of appendicitis. METHODS: We conducted a pragmatic, nonblinded, noninferiority, randomized trial comparing antibiotic therapy (10-day course) with appendectomy in patients with appendicitis at 25 U.S. centers. The primary outcome was 30-day health status, as assessed with the European Quality of Life-5 Dimensions (EQ-5D) questionnaire (scores range from 0 to 1, with higher scores indicating better health status; noninferiority margin, 0.05 points). Secondary outcomes included appendectomy in the antibiotics group and complications through 90 days; analyses were prespecified in subgroups defined according to the presence or absence of an appendicolith. RESULTS: In total, 1552 adults (414 with an appendicolith) underwent randomization; 776 were assigned to receive antibiotics (47% of whom were not hospitalized for the index treatment) and 776 to undergo appendectomy (96% of whom underwent a laparoscopic procedure). Antibiotics were noninferior to appendectomy on the basis of 30-day EQ-5D scores (mean difference, 0.01 points; 95% confidence interval [CI], -0.001 to 0.03). In the antibiotics group, 29% had undergone appendectomy by 90 days, including 41% of those with an appendicolith and 25% of those without an appendicolith. Complications were more common in the antibiotics group than in the appendectomy group (8.1 vs. 3.5 per 100 participants; rate ratio, 2.28; 95% CI, 1.30 to 3.98); the higher rate in the antibiotics group could be attributed to those with an appendicolith (20.2 vs. 3.6 per 100 participants; rate ratio, 5.69; 95% CI, 2.11 to 15.38) and not to those without an appendicolith (3.7 vs. 3.5 per 100 participants; rate ratio, 1.05; 95% CI, 0.45 to 2.43). The rate of serious adverse events was 4.0 per 100 participants in the antibiotics group and 3.0 per 100 participants in the appendectomy group (rate ratio, 1.29; 95% CI, 0.67 to 2.50). CONCLUSIONS: For the treatment of appendicitis, antibiotics were noninferior to appendectomy on the basis of results of a standard health-status measure. In the antibiotics group, nearly 3 in 10 participants had undergone appendectomy by 90 days. Participants with an appendicolith were at a higher risk for appendectomy and for complications than those without an appendicolith. (Funded by the Patient-Centered Outcomes Research Institute; CODA ClinicalTrials.gov number, NCT02800785.).

Performance of PCR/Electrospray Ionization-Mass Spectrometry on Whole Blood for Detection of Bloodstream Microorganisms in Patients with Suspected Sepsis.

Blood culture (BC) often fails to detect bloodstream microorganisms in sepsis. However, molecular diagnostics hold great potential. The molecular method PCR/electrospray ionization-mass spectrometry (PCR/ESI-MS) can detect DNA from hundreds of different microorganisms in whole blood. The aim of the present study was to evaluate the performance of this method in a multicenter study including 16 teaching hospitals in the United States (n = 13) and Europe (n = 3). First, on testing of 2,754 contrived whole blood samples, with or without spiked microorganisms, PCR/ESI-MS produced 99.1% true-positive and 97.2% true-negative results. Second, among 1,460 patients with suspected sepsis (sepsis-2 definition), BC and PCR/ESI-MS on whole blood were positive in 14.6% and 25.6% of cases, respectively, with the following result combinations: BC positive and PCR/ESI-MS negative, 4.3%; BC positive and PCR/ESI-MS positive, 10.3%; BC negative and PCR/ESI-MS positive, 15.3%; and BC negative and PCR/ESI-MS negative, 70.1%. Compared with BC, PCR/ESI-MS showed the following sensitivities (coagulase-negative staphylococci not included): Gram-positive bacteria, 58%; Gram-negative bacteria, 78%; and Candida species, 83%. The specificities were >94% for all individual species. Patients who had received prior antimicrobial medications (n = 603) had significantly higher PCR/ESI-MS positivity rates than patients without prior antimicrobial treatment-31% versus 22% (P < 0.0001)-with pronounced differences for Gram-negative bacteria and Candida species. In conclusion, PCR/ESI-MS showed excellent performance on contrived samples. On clinical samples, it showed high specificities, moderately high sensitivities for Gram-negative bacteria and Candida species, and elevated positivity rates during antimicrobial treatment. These promising results encourage further development of molecular diagnostics to be used with whole blood for detection of bloodstream microorganisms in sepsis.

Exebacase for patients with Staphylococcus aureus bloodstream infection and endocarditis.

BACKGROUNDNovel therapeutic approaches are critically needed for Staphylococcus aureus bloodstream infections (BSIs), particularly for methicillin-resistant S. aureus (MRSA). Exebacase, a first-in-class antistaphylococcal lysin, is a direct lytic agent that is rapidly bacteriolytic, eradicates biofilms, and synergizes with antibiotics.METHODSIn this superiority-design study, we randomly assigned 121 patients with S. aureus BSI/endocarditis to receive a single dose of exebacase or placebo. All patients received standard-of-care antibiotics. The primary efficacy endpoint was clinical outcome (responder rate) on day 14.RESULTSClinical responder rates on day 14 were 70.4% and 60.0% in the exebacase + antibiotics and antibiotics-alone groups, respectively (difference = 10.4, 90% CI [-6.3, 27.2], P = 0.31), and were 42.8 percentage points higher in the prespecified exploratory MRSA subgroup (74.1% vs. 31.3%, difference = 42.8, 90% CI [14.3, 71.4], ad hoc P = 0.01). Rates of adverse events (AEs) were similar in both groups. No AEs of hypersensitivity to exebacase were reported. Thirty-day all-cause mortality rates were 9.7% and 12.8% in the exebacase + antibiotics and antibiotics-alone groups, respectively, with a notable difference in MRSA patients (3.7% vs. 25.0%, difference = -21.3, 90% CI [-45.1, 2.5], ad hoc P = 0.06). Among MRSA patients in the United States, median length of stay was 4 days shorter and 30-day hospital readmission rates were 48% lower in the exebacase-treated group compared with antibiotics alone.CONCLUSIONThis study establishes proof of concept for exebacase and direct lytic agents as potential therapeutics and supports conduct of a confirmatory study focused on exebacase to treat MRSA BSIs.TRIAL REGISTRATIONClinicaltrials.gov NCT03163446.FUNDINGContraFect Corporation.

Derivation and Validation of a Clinical Decision Guideline for Influenza Testing in 4 US Emergency Departments.

BACKGROUND: An accurate diagnosis of influenza is essential for appropriate antiviral treatment, in accordance with Centers for Disease Control and Prevention (CDC) guidelines. However, no clear guidance exists on which patients should be tested. We sought to develop a clinical decision guideline (CDG) to inform influenza testing decisions for those adult emergency department (ED) patients deemed appropriate for antiviral treatment by CDC guidelines. METHODS: A prospective cohort study was performed at 4 US EDs. From November 2013 to April 2014, we enrolled adult ED patients with fever or respiratory symptoms who met criteria for antiviral treatment, per 2013 CDC guidelines. All patients were tested for influenza using polymerase chain reaction. Data were randomly split into derivation (80%) and validation (20%) data sets. A discrete set of independent variables was selected by logistic regression, using the derivation set to create a scoring system, with a target sensitivity of at least 90%. The derived CDG was then validated. RESULTS: Of 1941 enrolled participants, 183 (9.4%) had influenza. The derived CDG included new or increased cough (2 points), headache (1 point), subjective fever (1 point), and triage temperature >100.4°C (1 point), with a score of ≥3 indicating influenza testing was warranted. The CDG had a sensitivity and specificity of 94.1% and 36.6%, respectively, in the derivation set and of 91.5% and 34.6%, respectively, in the validation set. CONCLUSIONS: A CDG with high sensitivity was derived and validated. Incorporation into practice could standardize testing for high-risk patients in adult EDs during influenza seasons, potentially improving diagnoses and treatment. CLINICAL TRIAL REGISTRATION: NCT01947049.

Oral Lefamulin vs Moxifloxacin for Early Clinical Response Among Adults With Community-Acquired Bacterial Pneumonia: The LEAP 2 Randomized Clinical Trial.

IMPORTANCE: New antibacterials are needed to treat community-acquired bacterial pneumonia (CABP) because of growing antibacterial resistance and safety concerns with standard care. OBJECTIVE: To evaluate the efficacy and adverse events of a 5-day oral lefamulin regimen in patients with CABP. DESIGN, SETTING, AND PARTICIPANTS: A phase 3, noninferiority randomized clinical trial conducted at 99 sites in 19 countries that included adults aged 18 years or older with a Pneumonia Outcomes Research Team (PORT) risk class of II, III, or IV; radiographically documented pneumonia; acute illness; 3 or more CABP symptoms; and 2 or more vital sign abnormalities. The first patient visit was on August 30, 2016, and patients were followed up for 30 days; the final follow-up visit was on January 2, 2018. INTERVENTIONS: Patients were randomized 1:1 to receive oral lefamulin (600 mg every 12 hours for 5 days; n = 370) or moxifloxacin (400 mg every 24 hours for 7 days; n = 368). MAIN OUTCOMES AND MEASURES: The US Food and Drug Administration (FDA) primary end point was early clinical response at 96 hours (within a 24-hour window) after the first dose of either study drug in the intent-to-treat (ITT) population (all randomized patients). Responders were defined as alive, showing improvement in 2 or more of the 4 CABP symptoms, having no worsening of any CABP symptoms, and not receiving any nonstudy antibacterial drug for current CABP episode. The European Medicines Agency coprimary end points (FDA secondary end points) were investigator assessment of clinical response at test of cure (5-10 days after last dose) in the modified ITT population and in the clinically evaluable population. The noninferiority margin was 10% for early clinical response and investigator assessment of clinical response. RESULTS: Among 738 randomized patients (mean age, 57.5 years; 351 women [47.6%]; 360 had a PORT risk class of III or IV [48.8%]), 707 (95.8%) completed the trial. Early clinical response rates were 90.8% with lefamulin and 90.8% with moxifloxacin (difference, 0.1% [1-sided 97.5% CI, -4.4% to ∞]). Rates of investigator assessment of clinical response success were 87.5% with lefamulin and 89.1% with moxifloxacin in the modified ITT population (difference, -1.6% [1-sided 97.5% CI, -6.3% to ∞]) and 89.7% and 93.6%, respectively, in the clinically evaluable population (difference, -3.9% [1-sided 97.5% CI, -8.2% to ∞]) at test of cure. The most frequently reported treatment-emergent adverse events were gastrointestinal (diarrhea: 45/368 [12.2%] in lefamulin group and 4/368 [1.1%] in moxifloxacin group; nausea: 19/368 [5.2%] in lefamulin group and 7/368 [1.9%] in moxifloxacin group). CONCLUSIONS AND RELEVANCE: Among patients with CABP, 5-day oral lefamulin was noninferior to 7-day oral moxifloxacin with respect to early clinical response at 96 hours after first dose. TRIAL REGISTRATIONS: ClinicalTrials.gov Identifier: NCT02813694; European Clinical Trials Identifier: 2015-004782-92.