Real-World Effectiveness of Intravenous and Oral Antibiotic Stepdown Strategies for Gram-Negative Complicated Urinary Tract Infection With Bacteremia.

Background: Robust data are lacking regarding the optimal route, duration, and antibiotic choice for gram-negative bloodstream infection from a complicated urinary tract infection source (GN-BSI/cUTI). Methods: In this multicenter observational cohort study, we simulated a 4-arm registry trial using a causal inference method to compare effectiveness of the following regimens for GN-BSI/cUTI: complete course of an intravenous ß-lactam (IVBL) or oral stepdown therapy within 7 days using fluoroquinolones (FQs), trimethoprim-sulfamethoxazole (TMP-SMX), or high-bioavailability ß-lactams (HBBLs). Adults treated between January 2016 and December 2022 for Escherichia coli or Klebsiella species GN-BSI/cUTI were included. Propensity weighting was used to balance characteristics between groups. The 60-day recurrence was compared using a multinomial Cox proportional hazards model with probability of treatment weighting. Results: Of 2571 patients screened, 759 (30%) were included. Characteristics were similar between groups. Compared with IVBLs, we did not observe a difference in effectiveness for FQs (adjusted hazard ratio, 1.09 [95% confidence interval, .49-2.43]) or TMP-SMX (1.44 [.54-3.87]), and the effectiveness of TMP-SMX/FQ appeared to be optimal at durations of >10 days. HBBLs were associated with nearly 4-fold higher risk of recurrence (adjusted hazard ratio, 3.83 [95% confidence interval, 1.76-8.33]), which was not mitigated by longer treatment durations. Most HBBLs (67%) were not optimally dosed for bacteremia. Results were robust to multiple sensitivity analyses. Conclusions: These real-world data suggest that oral stepdown therapy with FQs or TMP-SMX have similar effectiveness as IVBLs. HBBLs were associated with higher recurrence rates, but dosing was suboptimal. Further data are needed to define optimal dosing and duration to mitigate treatment failures.

Oral ß-Lactams, Fluoroquinolones, or Trimethoprim-Sulfamethoxazole for Definitive Treatment of Uncomplicated Escherichia coli or Klebsiella Species Bacteremia From a Urinary Tract Source.

Background: Fluoroquinolones (FQs) are effective for oral step-down therapy for gram-negative bloodstream infections but are associated with unfavorable toxic effects. Robust data are lacking for trimethoprim-sulfamethoxazole (TMP-SMX) and high-bioavailability ß-lactams (HBBLs). Methods: In this multicenter observational cohort study, we simulated a 3-arm registry trial using causal inference methods to compare the effectiveness of FQs, TMP-SMX, or HBBLs for gram-negative bloodstream infections oral step-down therapy. The study included adults treated between January 2016 and December 2022 for uncomplicated Escherichia coli or Klebsiella species bacteremia of urinary tract origin who were who were transitioned to an oral regimen after ≤4 days of effective intravenous antibiotics. Propensity weighting was used to balance characteristics between groups. 60-day recurrence was compared using a multinomial Cox proportional hazards model with probability of treatment weighting. Results: Of 2571 patients screened, 648 (25%) were included. Their median age (interquartile range) was 67 (45-78) years, and only 103 (16%) were male. Characteristics were well balanced between groups. Compared with FQs, TMP-SMX had similar effectiveness (adjusted hazard ratio, 0.91 [95% confidence interval, .30-2.78]), and HBBLs had a higher risk of recurrence (2.19 [.95-5.01]), although this difference was not statistically significant. Most HBBLs (70%) were not optimally dosed for bacteremia. A total antibiotic duration ≤8 days was associated with a higher recurrence rate in select patients with risk factors for failure. Conclusions: FQs and TMP-SMX had similar effectiveness in this real-world data set. HBBLs were associated with higher recurrence rates but suboptimal dosing may have contributed. Further studies are needed to define optimal BL dosing and duration to mitigate treatment failures.

Outcomes of patients with bacteriuria/pyuria of clinically undetermined significance (BPCUS) treated with antibiotics in 23 community hospital emergency departments.

The optimal management of bacteriuria/pyuria of clinically undetermined significance (BPCUS) is unknown. Among 220 emergency department patients prescribed antibiotics for BPCUS, we found frequent readmissions, which were mitigated by outpatient follow-up visits. Observation and follow-up for an unknown diagnosis should be emphasized over antibiotics due to high likelihood of readmissions.

Systematic Review of Piperacillin-Tazobactam and Vancomycin Y-Site Compatibility: Consideration of Concentration and Solution Variability.

Simultaneous administration of vancomycin and piperacillin-tazobactam (VPT) poses significant challenges related to physical and chemical compatibility, as well as clinical practice. A systematic review of available literature related to VPT Y-site compatibility was performed. Data was collected from primary and tertiary sources. Seven articles were included in addition to one internal assessment and one review article and information from tertiary drug databases. The literature supports the simultaneous administration via Y-site of piperacillin-tazobactam 33.75 mg/mL in normal saline (NS) and vancomycin 4 to 8 mg/mL in NS. The same drug products at differing concentrations, diluents, storage conditions, or preparations outside of this recommendation should be considered incompatible.

Antibiotic prescribing for adult bacteriuria and pyuria in community hospital emergency departments.

OBJECTIVE: To describe emergency department (ED) antibiotic prescribing for urinary tract infections (UTIs) and asymptomatic bacteriuria (ASB) and to identify improvement opportunities. METHODS: Patients treated for UTI in 16 community hospital EDs were reviewed to identify prescribing that was unnecessary (any treatment for ASB, duration >7 days for cystitis or >14 days for pyelonephritis) or suboptimal [ineffective antibiotics (nitrofurantoin/fosfomycin) or duration <7 days for pyelonephritis]. Duration criteria were based on recommendations for complicated UTI since criteria for uncomplicated UTI were not reviewed. 14-day repeat ED visits were evaluated. RESULTS: Of 250,788 ED visits, UTI was diagnosed in 13,466 patients (5%), and 1427 of these (11%) were manually reviewed. 286/1427 [20%, 95% CI: 18-22%] met criteria for ASB and received 2068 unnecessary antibiotic days [mean (±SD) 7 (2) days]. Mean treatment duration was 7 (2) days for cystitis and 9 (2) days for pyelonephritis. Of 446 patients with cystitis, 128 (29%) were prescribed >7 days (total 396 unnecessary). Of 422 pyelonephritis patients, 0 (0%) were prescribed >14 days, 20 (5%) were prescribed <7 days, and 9 (2%) were given ineffective antibiotics. Overall, prescribing was unnecessary or suboptimal in 443/1427 [31%, 95% CI: 29-33%] resulting in 2464/11,192 (22%) unnecessary antibiotic days and 8 (0.5%) preventable ED visits. CONCLUSIONS: Among reviewed patients, poor UTI prescribing in 16 EDs resulted in unnecessary antibiotic days and preventable readmissions. Key areas for improvement include non-treatment of ASB and shorter durations for cystitis.

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 ß-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 ß-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.

Rate of positive cultures necessitating definitive treatment in patients receiving empiric vancomycin therapy.

Vancomycin is a commonly prescribed empiric antibiotic used when methicillin-resistant Staphylococcus aureus (MRSA) infection is suspected. In this study, we aimed to determine the rate of culture-positive infection requiring vancomycin therapy.

Clinical Pharmacist Management of Bacteremia in a Community Hospital Emergency Department.

BACKGROUND: Bacteremia is a serious condition that leads to high morbidity and mortality. Data describing pharmacist involvement in the management of bacteremia in the emergency department are lacking. OBJECTIVE: To determine if pharmacist involvement in the management of bacteremia in the emergency department (ED) led to an increase in appropriate treatment of bacteremia as well as improvements in patient outcomes. METHODS: The primary outcome of this retrospective cohort study was the rate of appropriate treatment of bacteremia. Secondary outcomes included the rate of unplanned, infectious disease-related 90-day admission or readmission to the ED or hospital as well as infectious disease-related 90-day mortality. All patients seen in the ED and subsequently discharged who had a positive blood culture determined not to be a contaminant were included in the study. Patients were analyzed in 2 cohorts: those that were physician managed (107 patients) and those that were pharmacist managed (138 patients). RESULTS: In the physician-managed cohort, 50 of 107 (47%) patients were treated appropriately compared with 131 of 138 (95%) patients in the pharmacist-managed cohort ( P < 0.0001). There was also a decrease in attributable 90-day admission or readmission in pharmacist-managed patients, which occurred in 4 of 138 patients (2.9%) versus the physician-managed patient cohort in which 13 of 107 patients (12.1%) were readmitted ( P = 0.01). There was no difference in mortality between the groups ( P = 0.8337). CONCLUSION: Pharmacist involvement in the management of bacteremia in the ED was associated with higher rates of appropriate treatment and a corresponding decrease in the rates of attributable 90-day admission or readmission to the hospital or ED.

Pharmacist-driven antimicrobial stewardship program in an institution without infectious diseases physician support.

PURPOSE: Improved drug-utilization and cost outcomes achieved by a pharmacist-led antimicrobial stewardship program (ASP) are described. SUMMARY: Pharmacists may be tasked to lead ASP development and implementation with little or no support from an infectious diseases (ID) physician and other hospital personnel whose involvement on ASP teams is recommended (e.g., clinical microbiologists, infection control specialists, hospital epidemiologists). Several years ago, Intermountain Healthcare's 325-bed McKay-Dee Hospital in Utah implemented an ASP led by an antimicrobial stewardship pharmacist. In addition to reviewing patient profiles and meeting with physicians to discuss cases daily (Monday-Friday), the pharmacist was available to provide afterhours phone consultations; support was provided by an infection prevention nurse, two physician ASP champions, the pharmacy leadership, pharmacy informatics and hospital laboratory personnel, and the chief medical officer. In the program's first 33 months, the pharmacist made a total of 2,457 interventions or recommendations, with an acceptance rate of 91.8%. Comparison of selected outcomes during one-year periods before and after ASP implementation indicated substantial decreases in the utilization of four commonly used antimicrobial agents and classes (carbapenems, daptomycin, echinocandins, and levofloxacin) in the postimplementation period, with a significant decline in the average length of stay for community-acquired pneumonia (mean ± S.D., 2.69 ± 0.10 days versus 3.40 ± 0.23 days; p = 0.03). Two years after ASP implementation, annual cost savings attributed to the program were estimated at $355,000. CONCLUSION: In the absence of ID physician support and oversight, the pharmacist-led ASP achieved substantial reductions in antimicrobial utilization and associated expenditures.

Optimization of anti-pseudomonal antibiotics for cystic fibrosis pulmonary exacerbations: V. Aminoglycosides.

Intravenous (IV) anti-pseudomonal aminoglycosides (i.e., amikacin and tobramycin) have been shown to be tolerable and effective in the treatment of acute pulmonary exacerbations (APEs) in both pediatric and adult patients with cystic fibrosis. The aim of this review is to provide an evidence-based summary of pharmacokinetic/pharmacodynamic, tolerability, and efficacy studies utilizing IV amikacin, gentamicin, and tobramycin in the treatment of APE and to highlight areas where further investigation is needed. The Cystic Fibrosis Foundation Pulmonary Guidelines recommend that once-daily administration of aminoglycosides is preferred over three times per day in the treatment of an APE. The literature supports dosing ranges for amikacin and tobramycin of 30-35 and 7-15 mg/kg/day, respectively, given once daily, with subsequent doses determined by therapeutic drug concentration monitoring. The literature does not support the routine use of gentamicin in the treatment of APE due to a lack of studies showing efficacy and evidence indicating an increased risk of nephrotoxicity. Further studies are needed to determine the optimal dosing strategy of amikacin in the treatment of an APE, and to further identify risk factors and determinants that influence the development of P. aeruginosa resistance with once-daily administration of tobramycin.

Optimization of anti-pseudomonal antibiotics for cystic fibrosis pulmonary exacerbations: VI. Executive summary.

Acute pulmonary exacerbations (APE) are well-described complications of cystic fibrosis (CF) and are associated with progressive morbidity and mortality. Despite aggressive management with two or more intravenous anti-pseudomonal agents, approximately 25% of exacerbations will result in a loss of lung function. The aim of this review is to provide an overview of the classes of intravenous anti-pseudomonal antibiotics, the findings of anti-pseudomonal antibiotic utilization surveys, the current antibiotic dosing recommendations from the U.S. and Europe, and the pharmacokinetic (PK) and pharmacodynamic (PD) differences between CF and non-CF individuals. Anti-pseudomonal antibiotic classes include beta-lactams, aminoglycosides, fluoroquinolones, and colistimethate sodium. Recent surveys of antibiotic utilization in CF Foundation-accredited care centers have shown that a large number of centers are not following recommended dosing strategies despite published recommendations in the U.S. and Europe. The recommended doses for anti-pseudomonal antibiotics may be higher than FDA-approved doses due to PK and PD differences. As a large portion of CF patients will not regain their lung function following an APE, it seems possible that currently available anti-pseudomonal agents are being used sub-optimally. As new anti-pseudomonal agents are not currently available, we suggest the need to optimize antibiotic dosing and dosing regimens used to treat pulmonary exacerbations in an effort to improve outcomes for CF patients infected with Pseudomonas aeruginosa.

Optimization of anti-pseudomonal antibiotics for cystic fibrosis pulmonary exacerbations: IV. colistimethate sodium.

Patients with cystic fibrosis (CF) often experience acute pulmonary exacerbations (APE) and may be treated with a wide variety of intravenous antibiotics. The aim of this review is to provide an evidence-based summary of pharmacokinetic/pharmacodynamic (PK/PD), tolerability, and efficacy studies utilizing the intravenous (IV) polymixin antibiotic colistimethate sodium (CMS) in the treatment of APE and to identify areas where further study is warranted. Currently, there is not an international standard on the labeling of CMS products. As a result, this has lead to confusion in the interpretation of the literature with respect to efficacy, tolerance, and optimal dosing strategy. The dosing ranges of IV CMS from the literature are 5.3-12.9 mg/kg/day, maximum 480 mg per day for 60 kg patient (Colomycin® injection-European product) and 8-21.3 mg/kg/day, maximum 800 mg per day for 60 kg patient (Coly-Mycin M® parenteral-US product).The literature supports a CMS dose of 8 mg/kg/day divided every 8 hr (maximum 480 mg/day) for the treatment of APE secondary to Pseudomonas aeruginosa. The maximum recommended CMS dose of 480 mg/day is less than is recommended by the FDA-approved and CFF dosing guidelines but in agreement with UK CF Trust Antibiotic Working Group recommendations. There is debate over the frequency of CMS administration (once daily vs. thrice-daily) and its impact on resistance and clinical efficacy. Further study is needed to determine the tolerability and efficacy of extended-interval dosing of CMS in the treatment of APE.

Optimization of anti-pseudomonal antibiotics for cystic fibrosis pulmonary exacerbations: III. fluoroquinolones.

This review is the third installment in a comprehensive State of the Art series and aims to evaluate the use of fluoroquinolones in the management of P. aeruginosa infection in both children and adults with cystic fibrosis (CF). Oral and intravenous ciprofloxacin have been shown to be well-tolerated in the treatment of acute pulmonary exacerbations (APE) secondary to P. aeruginosa. Older literature supports an oral dosing regimen of 40 mg/kg/day divided every 12 hr, up to 2 g/day, and intravenous (IV) ciprofloxacin 30 mg/kg/day divided every 8 hr, maximum 1.2 g/day in children, and 750 mg administered orally twice a day or 400 mg IV every 8 hr in adults. However, a recent pharmacodynamic (PD) modeling study shows that the literature, U.S. Food and Drug Administration (FDA)-approved, and Cystic Fibrosis Foundation (CFF) guideline dosing regimens may be suboptimal for the treatment of P. aeruginosa in APE. Further study is warranted to determine if higher doses of ciprofloxacin are needed. Limited pharmacokinetic (PK), PK/PD, and efficacy studies involving levofloxacin exist in adult patients with CF. No pediatric data exists for levofloxacin in CF patients. Further study is needed to determine the tolerability and efficacy of levofloxacin in APE. At this time, the routine use of levofloxacin in the treatment of APE in pediatric and adult patients cannot be recommended.

Optimization of anti-pseudomonal antibiotics for cystic fibrosis pulmonary exacerbations: II. cephalosporins and penicillins.

Acute pulmonary exacerbations (APE) are well-described complications of cystic fibrosis (CF) and are associated with progressive morbidity and mortality. Despite aggressive management with two or more intravenous anti-pseudomonal agents, approximately 25% of exacerbations will result in a loss of lung function. The aim of this review is to provide an evidence-based summary of pharmacokinetic/pharmacodynamic (PK/PD), tolerability, and efficacy studies utilizing anti-pseudomonal cephalosporins (i.e., ceftazidime and cefepime) and penicillins (i.e., piperacillin-tazobactam and ticarcillin-clavulanate) in the treatment of APE and to identify areas where further study is warranted. The ceftazidime and cefepime dosing ranges from the literature are 200-400 mg/kg/day divided every 6-8 hr, maximum 8-12 g/day, and 150-200 mg/kg/day divided every 6-8 hr, up to 6-8 g/day, respectively. The literature supported dosing ranges for piperacillin and ticarcillin are 350-600 mg/kg/day divided every 4 hr, maximum 18-24 g/day of piperacillin component, and 400-750 mg/kg/day divided every 6 hr, up to 24-30 g/day of ticarcillin component, respectively. As a large portion of CF patients will not regain their lung function following an APE, we suggest the need to optimize antibiotic dosing and dosing regimens used to treat an APE in efforts to improve outcomes for CF patients infected with Pseudomonas aeruginosa. Future studies are needed to determine the clinical efficacy of higher than FDA-approved doses of ceftazidime, cefepime, and ticarcillin-clavulanate in APE. The usefulness of high dose piperacillin (>600 mg/kg/day) may be limited due to treatment-related adverse effects. Further understanding of these adverse effects in CF patients is needed.

Optimization of anti-pseudomonal antibiotics for cystic fibrosis pulmonary exacerbations: I. aztreonam and carbapenems.

Acute pulmonary exacerbations (APE) in cystic fibrosis (CF) are associated with loss of lung function that may require aggressive management with intravenous antibiotics. The aim of this review is to provide an evidence-based summary of pharmacokinetic/pharmacodynamic (PK/PD), tolerability, and efficacy studies utilizing aztreonam and anti-pseudomonal carbapenems (i.e., doripenem, imipenem-cilastatin, and meropenem) in the treatment of an APE, and to identify areas where further study is warranted. The current dosing recommendations in the United States and Europe for aztreonam are lower than the literature supported dosing range of 200-300 mg/kg/day divided every 6 hr, maximum 8-12 g/day. In vitro, PK/PD, and tolerability studies show the potential of doripenem 90 mg/kg/day divided every 8 hr, infused over 4 hr, maximum 6 g/day in the treatment of APE. Imipenem-cilastatin 100 mg/kg/day divided every 6 hr, maximum 4 g/day and meropenem 120 mg/kg/day divided every 8 hr, maximum 6 g/day have been shown to be tolerable and effective in the treatment of APE. With availability issues of new anti-pseudomonal agents and a large percentage of CF patients will not regain their lung function following an APE, we suggest the need to determine optimization of aztreonam and meropenem dosing in CF, as well as to determine the clinical efficacy of doripenem in the treatment of APE. The usefulness of imipenem-cilastatin may be limited due to the rapid development of resistance.

A survey of the utilization of anti-pseudomonal beta-lactam therapy in cystic fibrosis patients.

The purpose of this study was to characterize the utilization of anti-pseudomonal beta-lactam antibiotics in the treatment of acute pulmonary exacerbations (APE) among Cystic Fibrosis Foundation (CFF)-accredited care centers. An anonymous national cross-sectional survey of CFF-accredited care centers was performed using an electronic survey tool (SurveyMonkey.com®). One hundred and twenty-one of 261 centers completed the survey (46%) representing 56% (14,856/26,740) of patients in the CFF Patient Registry. One hundred and nineteen of 121 (98%) respondents reported using beta-lactams for the treatment of APE. Intermittent dosing regimens constituted 155/167 (93%) reported regimens, while extended infusions were 12/167 (7%). Ceftazidime was the most commonly utilized beta-lactam comprising 74/167 (44%) of all infusions (intermittent and extended) of which 70/74 (95%) were intermittent infusions. The majority of intermittent ceftazidime regimens (56/70; 80%) were at doses lower than CFF and European guidelines recommended doses. In conclusion, a great majority of respondents use intermittent anti-pseudomonal beta-lactam antibiotics, with over half of respondents utilizing lower than guidelines recommended doses. While this is of concern, it is not known if optimization of dosing strategies according to guidelines recommendations will result in clinical benefit.