Multicenter Cohort Study of Ceftaroline Versus Daptomycin for Treatment of Methicillin-Resistant Staphylococcus aureus Bloodstream Infection.

BACKGROUND: Observational data suggest ceftaroline may be effective for methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection (BSI), but comparative data with standard of care are limited. This analysis compares the outcomes of MRSA BSI treated with ceftaroline or daptomycin. METHODS: Multicenter, retrospective, observational cohort study of adult patients with MRSA BSI from 2010 to 2017. Patients treated with ≥72 hours of ceftaroline or daptomycin were included. Those clearing BSI before study drug and those with a pneumonia source were excluded. The primary outcome was composite treatment failure, defined as 30-day mortality, BSI duration ≥7 days on study drug, and 60-day MRSA BSI recurrence. Inverse probability of treatment weighted risk difference in composite failure between daptomycin and ceftaroline groups was computed and 15% noninferiority margin applied. RESULTS: Two hundred seventy patients were included; 83 ceftaroline and 187 daptomycin. Ceftaroline was noninferior to daptomycin with respect to composite failure (39% daptomycin, 32.5% ceftaroline; weighted risk difference, 7.0% [95% confidence interval, -5.0% to 19.0%]). No differences between treatment groups was observed for 30-day mortality or other secondary efficacy outcomes. Creatine phosphokinase elevation was significantly more common among daptomycin patients (5.3% vs 0%, P = .034). Rash was significantly more common among ceftaroline patients (10.8 vs 1.1%, P = .001). CONCLUSIONS: No difference in treatment failure or mortality was observed between MRSA BSI treated with ceftaroline or daptomycin. These data support future study of ceftaroline as a primary MRSA BSI treatment and current use of ceftaroline when an alternative to vancomycin and daptomycin is required.

Corrigendum to: The Impact of Concomitant Empiric Cefepime on Patient Outcomes of Methicillin-Resistant Staphylococcus aureus Bloodstream Infections Treated With Vancomycin.

[This corrects the article DOI: 10.1093/ofid/ofz079.].

Evaluation of the INCREMENT-CPE, Pitt Bacteremia and qPitt Scores in Patients with Carbapenem-Resistant Enterobacteriaceae Infections Treated with Ceftazidime-Avibactam.

BACKGROUND: The aim of this study was to evaluate the predictive performance of the INCREMENT-CPE (ICS), Pitt bacteremia score (PBS) and qPitt for mortality among patients treated with ceftazidime-avibactam for carbapenem-resistant Enterobacteriaceae (CRE) infections. METHODS: Retrospective, multicenter, cohort study of patients with CRE infections treated with ceftazidime-avibactam between 2015 and 2019. The primary outcome was 30-day all-cause mortality. Predictive performance was determined by assessing discrimination, calibration and precision. RESULTS: In total, 109 patients were included. Thirty-day mortality occurred in 18 (16.5%) patients. There were no significant differences in discrimination of the three scores [area under the curve (AUC) ICS 0.7039, 95% CI 0.5848-0.8230, PBS 0.6893, 95% CI 0.5709-0.8076, and qPitt 0.6847, 95% CI 0.5671-0.8023; P > 0.05 all pairwise comparisons]. All scores showed adequate calibration and precision. When dichotomized at the optimal cut-points of 11, 3, and 2 for the ICS, PBS, and qPitt, respectively, all scores had NPV > 90% at the expense of low PPV. Patients in the high-risk groups had a relative risk for mortality of 3.184 (95% CI 1.35-8.930), 3.068 (95% CI 1.094-8.606), and 2.850 (95% CI 1.016-7.994) for the dichotomized ICS, PBS, and qPitt, scores respectively. Treatment-related variables (early active antibiotic therapy, combination antibiotics and renal ceftazidime-avibactam dose adjustment) were not associated with mortality after controlling for the risk scores. CONCLUSIONS: In patients treated with ceftazidime-avibactam for CRE infections, mortality risk scores demonstrated variable performance. Modifications to scoring systems to more accurately predict outcomes in the era of novel antibiotics are warranted.

A Multicenter Evaluation of Vancomycin-Associated Acute Kidney Injury in Hospitalized Patients with Acute Bacterial Skin and Skin Structure Infections.

BACKGROUND: We sought to determine the real-world incidence of and risk factors for vancomycin-associated acute kidney injury (V-AKI) in hospitalized adults with acute bacterial skin and skin structure infections (ABSSSI). METHODS: Retrospective, observational, cohort study at ten U.S. medical centers between 2015 and 2019. Hospitalized patients treated with vancomycin (≥ 72 h) for ABSSSI and ≥ one baseline AKI risk factor were eligible. Patients with end-stage kidney disease, on renal replacement therapy or AKI at baseline, were excluded. The primary outcome was V-AKI by the vancomycin guidelines criteria. RESULTS: In total, 415 patients were included. V-AKI occurred in 39 (9.4%) patients. Independent risk factors for V-AKI were: chronic alcohol abuse (aOR 4.710, 95% CI 1.929-11.499), no medical insurance (aOR 3.451, 95% CI 1.310-9.090), ICU residence (aOR 4.398, 95% CI 1.676-11.541), Gram-negative coverage (aOR 2.926, 95% CI 1.158-7.392) and vancomycin duration (aOR 1.143, 95% CI 1.037-1.260). Based on infection severity and comorbidities, 34.7% of patients were candidates for oral antibiotics at baseline and 39.3% had non-purulent cellulitis which could have been more appropriately treated with a beta-lactam. Patients with V-AKI had significantly longer hospital lengths of stay (9 vs. 6 days, p = 0.001), higher 30-day readmission rates (30.8 vs. 9.0%, p < 0.001) and increased all-cause 30-day mortality (5.1 vs. 0.3%, p = 0.024) CONCLUSIONS: V-AKI occurred in approximately one in ten ABSSSI patients and may be largely prevented by preferential use of oral antibiotics whenever possible, using beta-lactams for non-purulent cellulitis and limiting durations of vancomycin therapy.

Real-World Experience with Ceftolozane-Tazobactam for Multidrug-Resistant Gram-Negative Bacterial Infections.

Our objective was to describe the prescribing practices, clinical characteristics, and outcomes of patients treated with ceftolozane-tazobactam (C/T) for multidrug-resistant (MDR) Gram-negative infections. This was a multicenter, retrospective, cohort study at eight U.S. medical centers (2015 to 2019). Inclusion criteria were age ≥18 years and receipt of C/T (≥72 hours) for suspected or confirmed MDR Gram-negative infection. The primary efficacy outcome, evaluated among patients with MDR Pseudomonas aeruginosa infections, was composite clinical failure, namely, 30-day all-cause mortality, 30-day recurrence, and/or failure to resolve or improve infection signs or symptoms after C/T treatment. In total, 259 patients were included, and P. aeruginosa was isolated in 236 (91.1%). The MDR and extremely drug-resistant phenotypes were detected in 95.8% and 37.7% of P. aeruginosa isolates, respectively. The most common infection source was the respiratory tract (62.9%). High-dose C/T was used in 71.2% of patients with a respiratory tract infection (RTI) overall but in only 39.6% of patients with an RTI who required C/T renal dose adjustment. In the primary efficacy population (n = 226), clinical failure and 30-day mortality occurred in 85 (37.6%) and 39 (17.3%) patients, respectively. New C/T MDR P. aeruginosa resistance was detected in 3 of 31 patients (9.7%) with follow-up cultures. Hospital-acquired infection and Acute Physiological and Chronic Health Evaluation II (APACHE II) score were independently associated with clinical failure (adjusted odds ratio [aOR], 2.472 and 95% confidence interval [CI], 1.322 to 4.625; and aOR, 1.068 and 95% CI, 1.031 to 1.106, respectively). Twenty-five (9.7%) patients experienced ≥1 adverse effect (9 acute kidney injury, 13 Clostridioides difficile infection, 1 hepatotoxicity, 2 encephalopathy, and 2 gastrointestinal intolerance). C/T addresses an unmet medical need in patients with MDR Gram-negative infections.

Daptomycin Plus ß-Lactam Combination Therapy for Methicillin-resistant Staphylococcus aureus Bloodstream Infections: A Retrospective, Comparative Cohort Study.

BACKGROUND: Mounting evidence suggests the addition of a ß-lactam (BL) to daptomycin (DAP) results in synergistic in vitro activity against methicillin-resistant Staphylococcus aureus (MRSA) and bolsters the innate immune response to infection. This study's objective was to provide clinical translation to these experimental data and determine if DAP+BL combination therapy results in improved clinical outcomes compared with treatment with DAP alone in patients with MRSA bloodstream infections (BSIs). METHODS: This was a retrospective, comparative cohort study conducted at 2 academic medical centers between 2008 and 2018. Adults with MRSA BSI treated with DAP for ≥72 hours and initiated ≤5 days of culture collection were included. Patients who received a BL for ≥24 hours and initiated ≤24 hours of DAP comprised the DAP+BL group. The primary outcome was composite clinical failure (60-day all-cause mortality and/or 60-day recurrence). Analyses were adjusted for confounding using inverse probability of treatment weighting (IPTW). RESULTS: A total of 229 patients were included (72 DAP+BL and 157 DAP). In unadjusted and IPTW-adjusted analyses, DAP+BL was associated with significantly reduced odds of clinical failure (odds ratio [OR], 0.362; 95% confidence interval [CI], .164-.801; adjusted OR, 0.386; 95% CI, .175-.853). Adjusted analyses restricted to prespecified subgroups based on infection complexity and baseline health status were consistent with the main analysis. CONCLUSIONS: The addition of a BL to DAP was associated with improved clinical outcomes in patients with MRSA BSI. This study provides support to ongoing and future studies evaluating the impact of combination therapy for invasive MRSA infections.Patients treated with daptomycin plus a ß-lactam for MRSA bloodstream infection had lower odds of composite clinical failure defined as 60-day all-cause mortality and/or 60-day recurrence compared with patients treated with daptomycin monotherapy after adjusting for confounding variables using inverse probability of treatment weighting.

The Impact of Concomitant Empiric Cefepime on Patient Outcomes of Methicillin-Resistant Staphylococcus aureus Bloodstream Infections Treated With Vancomycin.

Background: Data suggest that vancomycin + ß-lactam combinations improve the clearance of methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections (BSIs). However, it is unclear which specific ß-lactams confer benefit. This analysis evaluates the impact of concomitant empiric cefepime on outcomes of MRSA BSIs treated with vancomycin. Methods: This was a multicenter, retrospective cohort study of adults with MRSA BSIs from 2006 to 2017. Vancomycin + cefepime therapy was defined as ≥24 hours of cefepime during the first 72 hours of vancomycin. The primary outcome was microbiologic failure, defined as BSI duration ≥7 days and/or 60-day recurrence. Multivariable logistic regression was used to evaluate the association between vancomycin + cefepime therapy and binary outcomes. Cause-specific and subdistribution hazard models were used to evaluate the association between vancomycin + cefepime and BSI clearance. Results: Three hundred fifty-eight patients were included, 129 vancomycin and 229 vancomycin + cefepime. Vancomycin + cefepime therapy was independently associated with reduced microbiologic failure (adjusted odds ratio [aOR], 0.488; 95% confidence interval [CI], 0.271-0.741). This was driven by a reduction in BSI duration ≥7 days (vancomycin + cefepime aOR, 0.354; 95% CI, 0.202-0.621). Vancomycin + cefepime had no association with 30-day mortality (aOR, 0.952; 95% CI, 0.435-2.425). Vancomycin + cefepime was associated with faster BSI clearance in both cause-specific (hazard ratio [HR], 1.408; 95% CI, 1.125-1.762) and subdistribution hazard models (HR, 1.264; 95% CI, 1.040-1.536). Conclusions: Concomitant empiric cefepime improved MRSA BSI clearance and may be useful as the ß-lactam component of synergistic vancomycin + ß-lactam regimens when empiric or directed gram-negative coverage is desired.

The Impact of Concomitant Empiric Cefepime on Patient Outcomes of Methicillin-Resistant Staphylococcus aureus Bloodstream Infections Treated With Vancomycin.

BACKGROUND: Data suggest that vancomycin + ß-lactam combinations improve clearance of methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections (BSIs). However, it is unclear which specific ß-lactams confer benefit. This analysis evaluates the impact of concomitant empiric cefepime on outcomes of MRSA BSIs treated with vancomycin. METHODS: Retrospective cohort study of adults with MRSA BSI from 2006 to 2017. Vancomycin + cefepime therapy was defined as ≥24 hours of cefepime during the first 72 hours of vancomycin. The primary outcome was microbiologic failure, defined as BSI duration ≥7 days and/or 60-day recurrence. Multivariable logistic regression was used to evaluate the association between vancomycin + cefepime therapy and binary outcomes. Cause-specific and subdistribution hazard models were used to evaluate the association between vancomycin + cefepime and BSI clearance. RESULTS: Three hundred fifty-eight patients were included, 129 vancomycin and 229 vancomycin + cefepime. Vancomycin + cefepime therapy was independently associated with reduced microbiologic failure (adjusted odds ratio [aOR], 0.488; 95% confidence interval [CI], 0.271-0.741). This was driven by a reduction in the incidence of BSI durations ≥7 days (vancomycin + cefepime aOR, 0.354; 95% CI, 0.202-0.621). Vancomycin + cefepime had no association with 30-day mortality (aOR, 0.952; 95% CI, 0.435-2.425). Vancomycin + cefepime was associated with faster BSI clearance in both cause-specific (HR, 1.408; 95% CI, 1.125-1.762) and subdistribution hazard models (HR, 1.264; 95% CI, 1.040-1.536). CONCLUSIONS: Concomitant empiric cefepime improved MRSA BSI clearance and may be useful as the ß-lactam component of synergistic vancomycin + ß-lactam regimens when empiric or directed gram-negative coverage is desired.

Diagnostic Stewardship: A Clinical Decision Rule for Blood Cultures in Community-Onset Methicillin-Resistant Staphylococcus aureus (MRSA) Skin and Soft Tissue Infections.

INTRODUCTION: The emergence, spread and persistence of methicillin-resistant Staphylococcus aureus (MRSA) as a causative pathogen in community-onset (CO) skin and soft tissue infections (SSTIs) have resulted in substantial changes in the management of these infections. The indications for obtaining blood cultures in patients with CO-MRSA SSTIs remain poorly defined. The objectives of this study were to derive and validate a clinical decision rule that predicts the probability of MRSA bacteremia in CO-MRSA SSTIs and to identify a low-risk population for whom blood cultures may be safely omitted. METHODS: This was a retrospective, case-control study with an internal temporal validation cohort conducted at two large urban academic medical centers. Hospitalized adults with CO-MRSA SSTI between 2010 and 2018 were included. Independent predictors of MRSA bacteremia were identified through multivariable logistic regression. A decision rule was derived using weighted coefficient-based scoring. The decision rule was validated in an internal temporal validation cohort. RESULTS: A total of 307 patients (155 cases and 152 controls) were included in the derivation cohort. A decision rule was created with a "major criterion" defined as purulent cellulitis and "minor criteria" defined as abnormal temperature, intravenous drug use, leukocytosis, tachycardia, body mass index < 25 kg/m2 and non-upper extremity infection site. A blood culture is indicated by this rule for patients with one major or at least two minor criteria. Otherwise patients are classified as low risk, and blood cultures may be omitted. The sensitivity of the decision rule in the derivation and validation cohorts was 98.71% (95% CI 95.42%, 99.84%) and 95.65% (78.05%, 99.89%), respectively. The specificity was 23.03% (95% CI 16.59%, 30.54%) and 30.77% (95% CI 24.15%, 38.02%), respectively. CONCLUSION: The decision rule developed and validated in this study provides a standardized, evidenced-based approach to determine the need for blood cultures based on bacteremia risk.

A new simplified predictive model for mortality in methicillin-resistant Staphylococcus aureus bacteremia.

Adjustment for confounding is important in observational methicillin-resistant Staphylococcus aureus bacteremia (MRSAB) studies due to the wide spectrum of disease severity and baseline health status that patients present with. The objectives of this study were to develop a simplified MRSAB-specific scoring model to estimate the risk of 30-day all-cause mortality and to compare its performance to the APACHE II and Pitt Bacteremia scores. Retrospective, singe-center, cohort study in adults with MRSAB 2008 to 2018. Independent predictors of mortality were identified through multivariable logistic regression. A scoring model was derived using a regression coefficient-based scoring method. Discriminatory ability was assessed using the c statistic. A total of 455 patients were included. Thirty-day mortality was 16.3%. The MRSAB score consisted of six variables: age, respiratory rate, Glasgow Coma scale, renal failure, hospital-acquired MRSAB, and infective endocarditis or lower respiratory tract infection source. The score demonstrated very good discrimination (c statistic 0.8662, 95% CI 0.824-0.909) and was superior to the APACHE II (P = 0.043) and the Pitt bacteremia (P < 0.001) scores. A weighted combination of six independent variables routinely measured in patients with MRSAB can be used to predict, with high discrimination, 30-day all-cause mortality. External validation is required before widespread use.

Real-World Experience With Ceftazidime-Avibactam for Multidrug-Resistant Gram-Negative Bacterial Infections.

BACKGROUND: We conducted this study to describe the clinical characteristics, microbiology, and outcomes of patients treated with ceftazidime-avibactam (CZA) for a range of multidrug-resistant Gram-negative (MDR-GN) infections. METHODS: This is a multicenter, retrospective cohort study conducted at 6 medical centers in the United States between 2015 and 2019. Adult patients who received CZA (≥72 hours) were eligible. The primary outcome was clinical failure defined as a composite of 30-day all-cause mortality, 30-day microbiological failure, and/or failure to resolve or improve signs or symptoms of infection on CZA. RESULTS: In total, data from 203 patients were evaluated. Carbapenem-resistant Enterobacteriaceae (CRE) and Pseudomonas spp were isolated from 117 (57.6%) and 63 (31.0%) culture specimens, respectively. The most common infection sources were respiratory (37.4%), urinary (19.7%), and intra-abdominal (18.7%). Blood cultures were positive in 22 (10.8%) patients. Clinical failure, 30-day mortality, and 30-day recurrence occurred in 59 (29.1%), 35 (17.2%), and 12 (5.9%) patients, respectively. On therapy, CZA resistance developed in 1 of 62 patients with repeat testing. Primary bacteremia or respiratory tract infection and higher SOFA score were positively associated with clinical failure (adjusted odds ratio [aOR] = 2.270, 95% confidence interval [CI] = 1.115-4.620 and aOR = 1.234, 95% CI = 1.118-1.362, respectively). Receipt of CZA within 48 hours of infection onset was protective (aOR, 0.409; 95% CI, 0.180-0.930). Seventeen (8.4%) patients experienced a potential drug-related adverse effect (10 acute kidney injury, 3 Clostridioides difficile infection, 2 rash, and 1 each gastrointestinal intolerance and neutropenia). CONCLUSIONS: Ceftazidime-avibactam is being used to treat a range of MDR-GN infections including Pseudomonas spp as well as CRE.

Sequential intravenous-to-oral outpatient antibiotic therapy for MRSA bacteraemia: one step closer.

Background: Published guidelines call for prolonged courses of intravenous (iv) antibiotics for the treatment of MRSA bloodstream infection (BSI) to ensure eradication of deep foci and decrease relapse risk. Sequential iv-to-oral antibiotic therapy has been successfully applied to other serious infections but has not been evaluated for MRSA BSI. Objectives: To compare outcomes in adults completing MRSA BSI therapy with oral versus parenteral antibiotics in the outpatient setting [oral outpatient antibiotic therapy (OOAT) versus outpatient parenteral antibiotic therapy (OPAT)]. Methods: This was a single-centre, retrospective, cohort study between 2008 and 2018. The primary outcome was 90 day clinical failure (MRSA BSI recurrence, deep-seated MRSA infection or all-cause mortality). Analyses were adjusted for confounding using inverse probability of treatment weighting (IPTW). Results: A total of 492 patients were included (70 OOAT, 422 OPAT). In general, OOAT patients had characteristics consistent with a lower risk of poor outcomes; however, after IPTW key prognostic factors were balanced. In IPTW-adjusted analysis, there was non-significant reduction in the rate of 90 day clinical failure in the OOAT group compared with the OPAT group [adjusted HR (aHR) 0.379, 95% CI 0.131-1.101]. In analyses restricted to pre-specified subgroups defined by index infection complexity and comorbidity burden, findings were consistent with the main analysis. Furthermore, OOAT patients had a significantly reduced rate of 90 day hospital readmission (aHR 0.603, 95% CI 0.388-0.937). Conclusions: We provide preliminary evidence that selected patients with MRSA BSI may have at least equivalent clinical outcomes with OOAT versus OPAT and provide support to ongoing and future studies evaluating oral antibiotics for MRSA BSI.