Exploring variations in recommended first-choice therapy for complicated urinary tract infections in males: Insights from outpatient settings across age, race, and ethnicity

INTRODUCTION

There are known disparities in the treatment of infectious diseases. However, disparities in treatment of complicated urinary tract infections (UTIs) are largely uninvestigated.

OBJECTIVES

We characterized UTI treatment among males in Veterans Affairs (VA) outpatient settings by age, race, and ethnicity and identified demographic characteristics predictive of recommended first-choice antibiotic therapy.

METHODS

We conducted a national, retrospective cohort study of male VA patients diagnosed with a UTI and dispensed an outpatient antibiotic from January 2010 through December 2020. Recommended first-choice therapy for complicated UTI was defined as use of a recommended first-line antibiotic drug choice regardless of area of involvement (ciprofloxacin, levofloxacin, or sulfamethoxazole/trimethoprim) and a recommended duration of 7 to 10 days of therapy. Multivariable models were used to identify demographic predictors of recommended first-choice therapy (adjusted odds ratio [aOR] > 1).

RESULTS

We identified a total of 157,898 males diagnosed and treated for a UTI in the outpatient setting. The average antibiotic duration was 9.4 days (±standard deviation [SD] 4.6), and 47.6% of patients were treated with ciprofloxacin, 25.1% with sulfamethoxazole/trimethoprim, 7.6% with nitrofurantoin, and 6.6% with levofloxacin. Only half of the male patients (50.6%, n = 79,928) were treated with recommended first-choice therapy (first-line drug choice and appropriate duration); 77.6% (n = 122,590) were treated with a recommended antibiotic choice and 65.9% (n = 104,070) with a recommended duration. Age 18-49 years (aOR 1.07, 95% confidence interval [CI] 1.03-1.11) versus age ≥65 years was the only demographic factor predictive of recommended first-choice therapy.

CONCLUSIONS

Nearly half of the patients included in this study did not receive recommended first-choice therapies; however, racial and ethnic disparities were not identified. Underutilization of recommended first-choice antibiotic therapy in complicated UTIs continues to be an area of focus for antimicrobial stewardship programs.

Antibiotics on Demand: Advances in Asynchronous Telemedicine Call for Increased Antibiotic Surveillance

The rapid growth of telehealth services has brought about direct-to-consumer telemedicine platforms, enabling patients to request antibiotics online without a virtual or face-to-face consultation. While telemedicine aims to enhance accessibility, this trend raises significant concerns regarding appropriate antimicrobial use and patient safety. In this viewpoint, we share our first-hand experience with 2 direct-to-consumer platforms, where we intentionally sought inappropriate antibiotic prescriptions for nonspecific symptoms strongly indicative of a viral upper respiratory infection. Despite the lack of clear necessity, requested antibiotic prescriptions were readily transmitted to our local pharmacy following a simple monetary transaction. The effortless acquisition of patient-selected antibiotics online, devoid of personal interactions or consultations, underscores the urgent imperative for intensified antimicrobial stewardship initiatives led by state and national public health organizations in telehealth settings. By augmenting oversight and regulation, we can ensure the responsible and judicious use of antibiotics, safeguard patient well-being, and preserve the efficacy of these vital medications.

Real-world utilization of ceftazidime/avibactam among inpatients in the national Veterans Affairs Healthcare System

DISCLAIMER

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

PURPOSE

Multidrug-resistant (MDR) infections are challenging to treat due to underlying patient conditions, pathogen characteristics, and high antibiotic resistance rates. As newer antibiotic therapies come to market, limited data exist about their real-world utilization.

METHODS

This was a national retrospective cohort study of ceftazidime/avibactam (approved in 2015) utilization among inpatients from the Veterans Affairs (VA) Healthcare System, from 2015 through 2021. Joinpoint regression was used to estimate time trends in utilization.

RESULTS

Ceftazidime/avibactam use increased by 52.3% each year (days of therapy per 1,000 bed days; 95% confidence interval, 12.4%-106.4%). We identified 1,048 unique predominantly male (98.3%) and white (66.2%; Black, 27.7%) patients treated with ceftazidime/avibactam, with a mean (SD) age of 71.5 (11.9) years. The most commonly isolated organisms were Pseudomonas aeruginosa (36.3%; carbapenem resistant, 80.6%; MDR, 65.0%) and Klebsiella species (34.1%; carbapenem resistant, 78.4%; extended-spectrum cephalosporin resistant, 90.7%). Common comorbid conditions included hypertension (74.8%), nervous system disorders (60.2%), diabetes mellitus (48.7%), and cancer (45.1%). Median time to ceftazidime/avibactam initiation from admission was 6 days, with a median of 3 changes in therapy before ceftazidime/avibactam initiation and a subsequent median length of inpatient stay of 14 days (median of 8 days of ceftazidime/avibactam therapy). Treatment heterogeneity was high, both before ceftazidime/avibactam initiation (89.6%) and during ceftazidime/avibactam treatment (85.6%), and common concomitant antibiotics included vancomycin (41.4%), meropenem (24.1%), cefepime (15.2%), and piperacillin/tazobactam (15.2%). The inpatient mortality rate was 23.6%, and 20.8% of patients had a subsequent admission with ceftazidime/avibactam treatment.

CONCLUSION

Utilization of ceftazidime/avibactam increased from 2015 to 2021 in the national VA Healthcare System. Ceftazidime/avibactam was utilized in complex, difficult-to-treat patients, with substantial treatment heterogeneity and variation in the causative organism and culture site.

Nirmatrelvir/Ritonavir Utilization for the Treatment of Non-hospitalized Adults with COVID-19 in the National Veterans Affairs (VA) Healthcare System

INTRODUCTION

Limited data exist regarding real-world utilization of nirmatrelvir/ritonavir. We identified predictors of nirmatrelvir/ritonavir use among Veterans Affairs (VA) outpatients nationally.

METHODS

We conducted a retrospective cohort study among outpatients with coronavirus disease 2019 (COVID-19) who were eligible to receive nirmatrelvir/ritonavir between January and December of 2022, to identify factors associated with nirmatrelvir/ritonavir use (i.e., demographics, medical history, prior medication and healthcare exposures, frailty, and other clinical characteristics) using multivariable logistic regression.

RESULTS

We included 309,755 outpatients with COVID-19 who were eligible for nirmatrelvir/ritonavir, of whom 12.2% received nirmatrelvir/ritonavir. Nirmatrelvir/ritonavir uptake increased from 1.1% to 23.2% over the study period. Factors associated with nirmatrelvir/ritonavir receipt included receiving a COVID-19 booster vs. none (adjusted odds ratio [aOR] 2.19 [95% confidence interval [CI] 2.12-2.26]), age ≥ 50 vs. 18-49 years (aORs > 1.5 for all age groups ≥ 50 years), having HIV (aOR 1.36 [1.22-1.51]), being non-frail vs. severely frail (aOR 1.22 [1.13-1.33]), and having rheumatoid arthritis (aOR 1.12 [1.04-1.21). Those with concomitant use of potentially interacting antiarrhythmics (aOR 0.35 [0.28-0.45]), anticoagulants/antiplatelets (aOR 0.42 [0.40-0.45]), and/or psychiatric/sedatives (aOR 0.84 [0.81-0.87]) were less likely to receive nirmatrelvir/ritonavir.

CONCLUSIONS

Despite increases over time, overall utilization of nirmatrelvir/ritonavir was low. Predictors of nirmatrelvir/ritonavir utilization were consistent with known risk factors for progression to severe COVID-19, including older age and underlying medical conditions. Unvaccinated and undervaccinated patients and those receiving potentially interacting medications for cardiovascular or mental health conditions (antiarrhythmic, alpha-1 antagonist, anticoagulant/antiplatelet, sedative/hypnotic/psychiatric) were less likely to receive nirmatrelvir/ritonavir. Further education of prescribers and patients about nirmatrelvir/ritonavir treatment guidelines is needed to improve overall uptake and utilization in certain high-risk subpopulations.

Advancements in Novel Live Biotherapeutic Products for Clostridioides difficile Infection Prevention

The profound impact of the human microbiome on health and disease has captivated the interest of clinical and scientific communities. The human body hosts a vast array of microorganisms collectively forming the human microbiome, which significantly influences various physiological processes and profoundly shapes overall well-being. Notably, the gut stands out as an exceptional reservoir, harboring the most significant concentration of microorganisms, akin to an organ in itself. The gut microbiome's composition and function are influenced by genetics, environment, age, underlying conditions, and antibiotic usage, leading to dysbiosis and pathogenesis, such as Clostridioides difficile infection (CDI). Conventional CDI treatment, involving antibiotics like oral vancomycin and fidaxomicin, fails to address dysbiosis and may further disrupt gut microbial communities. Consequently, emerging therapeutic strategies are focused on targeting dysbiosis and restoring gut microbiota to advance CDI therapeutics. Fecal microbiota transplantation (FMT) has demonstrated remarkable efficacy in treating recurrent CDI by transferring processed stool from a healthy donor to a recipient, restoring gut dysbiosis and enhancing bacterial diversity. Moreover, 2 newer Food and Drug Administration (FDA)-approved live biotherapeutic products (LBP), namely, Fecal Microbiota Live-JSLM and Fecal Microbiota Spores Live-BRPK, have shown promise in preventing CDI recurrence. This review explores the role of the gut microbiota in preventing and treating CDI, with an emphasis on gut-based interventions like FMT and fecal microbiota-based products that hold potential for gut restoration and prevention of CDI recurrence. Understanding the microbiome's impact on CDI prevention and treatment offers valuable insights for advancing future CDI therapeutics.

Student pharmacists delivering academic detailing on adult pneumococcal vaccination to community pharmacists

BACKGROUND

Academic detailing is an educational outreach approach to disseminate evidence-based information to health care professionals and improve clinical decision making. Pharmacists and physicians are recognized as the most qualified individuals to perform academic detailing; however, trained student pharmacists may also serve as suitable academic detailers.

OBJECTIVES

To describe our academic detailing intervention that used trained student pharmacists to disseminate an updated pneumococcal vaccination clinical pathway (i.e., decision-support tool) and education to community pharmacists in Rhode Island and Massachusetts.

METHODS

We updated an academic detailing initiative that included a pneumococcal vaccination clinical pathway and education for community pharmacists in 2021. Two University of Rhode Island (URI) College of Pharmacy pharmacist faculty members trained 6 student pharmacists to perform academic detailing. Student pharmacists visited URI-affiliated community pharmacies throughout Rhode Island and Massachusetts. After each session, each participant received a 6-question anonymous paper survey to assess the effectiveness of the updated pathway and academic detailing session. The survey used a 5-point Likert-type scale. We assessed the percentage agreement with each question.

RESULTS

Academic detailing was delivered to 76 community pharmacists from May to August 2021. Most respondents agreed (89.2%, 58/65) that their knowledge of which patient populations met eligibility for the pneumococcal conjugate vaccine or pneumococcal polysaccharide vaccine improved. Respondents were confident they could apply the knowledge gained (93.8%, 61/65) and intended to apply the pathway (93.8%, 61/65) to clinical practice. Most respondents expected vaccination practices to change because of the academic detailing and education materials received (83.6%, 51/61). Almost all respondents (95.4%, 62/65) found the educational materials easy to understand.

CONCLUSION

Trained student pharmacists can deliver academic detailing regarding adult pneumococcal vaccination to community pharmacists. Enlisting the help of student pharmacists may be a sustainable approach to academic detailing and provides students with valuable opportunities to practice delivering educational outreach to community pharmacists.

Decreasing Antibiotic Resistance Trends Nationally in Gram-Negative Bacteria Across United States Veterans Affairs Medical Centers, 2011-2020

INTRODUCTION

Gram-negative resistance is a well-acknowledged public health threat. Surveillance data can be used to monitor resistance trends and identify strategies to mitigate their threat. The objective of this study was to assess antibiotic resistance trends in Gram-negative bacteria.

METHODS

The first cultures of Pseudomonas aeruginosa, Citrobacter, Escherichia coli, Enterobacter, Klebsiella, Morganella morganii, Proteus mirabilis, and Serratia marcescens per hospitalized patient per month collected from 125 Veterans Affairs Medical Centers (VAMCs) between 2011 to 2020 were included. Time trends of resistance phenotypes (carbapenem, fluoroquinolone, extended-spectrum cephalosporin, multi-drug, and difficult-to-treat) were analyzed with Joinpoint regression to estimate average annual percent changes (AAPC) with 95% confidence intervals and p values. A 2020 antibiogram of reported antibiotic percent susceptibilities was also created to evaluate resistance rates at the beginning of the COVID-19 pandemic.

RESULTS

Among 40 antimicrobial resistance phenotype trends assessed in 494,593 Gram-negative isolates, there were no noted increases; significant decreases were observed in 87.5% (n = 35), including in all P. aeruginosa, Citrobacter, Klebsiella, M. morganii, and S. marcescens phenotypes (p < 0.05). The largest decreases were seen in carbapenem-resistant phenotypes of P. mirabilis, Klebsiella, and M. morganii (AAPCs: - 22.9%, - 20.7%, and - 20.6%, respectively). In 2020, percent susceptibility was over 80% for all organisms tested against aminoglycosides, cefepime, ertapenem, meropenem, ceftazidime-avibactam, ceftolozane-tazobactam, and meropenem-vaborbactam.

CONCLUSION

We observed significant decreases in antibiotic resistance for P. aeruginosa and Enterobacterales over the past decade. According to the 2020 antibiogram, in vitro antimicrobial activity was observed for most treatment options. These results may be related to the robust infection control and antimicrobial stewardship programs instituted nationally among VAMCs.

Staphylococcal Biofilm: Penetration and bioavailability of vancomycin with or without rifampin

We measured antibiotic penetration and bioavailability in staphylococcus biofilms using simulated humanized concentrations of fluorescent vancomycin plus or minus rifampin. Vancomycin percent recovery across biofilm layers was:upper = 46%, middle = 40%, and lower = 33%. Vancomycin plus rifampin was not significantly different (P = 0.65). Addition of rifampin did not improve vancomycin penetration across biofilm layers.

Treatment, clinical outcomes, and predictors of mortality among a national cohort of hospitalized patients with Stenotrophomonas maltophilia infection

OBJECTIVES

To analyze treatment, clinical outcomes, and predictors of inpatient mortality in hospitalized patients with Stenotrophomonas maltophilia infection.

STUDY DESIGN

Retrospective cohort study.

METHODS

We included patients admitted to Veterans Affairs hospitals nationally with S. maltophilia cultures and treatment from 2010 to 2019. We described patient and clinical characteristics, antibiotic treatment, and clinical outcomes. Univariate and multivariable logistic regression were used to evaluate predictors of inpatient mortality.

RESULTS

We identified 3891 hospitalized patients treated for an S. maltophilia infection, of which 13.7% died during admission. The most common antibiotic agents were piperacillin/tazobactam (39.7%), sulfamethoxazole/trimethoprim (23.3%), and levofloxacin (23.2%). Combination therapy was used in 16.6% of patients. Independent predictors of inpatient mortality identified in multivariable analysis included the following: presence of current acute respiratory failure (adjusted odds ratio [aOR] 4.74, 95% confidence interval [CI] 3.63-6.19), shock (aOR 3.00, 95% CI 2.31-3.90), acute renal failure (aOR 2.06, 95% CI 1.64-2.60), and septicemia (aOR 1.90, 95% CI 1.49-2.42), age 65 years and older (aOR 2.05, 95% CI 1.07-3.94, reference age 18-49 years), hospital-acquired infection (aOR 1.87, 95% CI 1.48-2.37), Black (aOR 1.58, 95% CI 1.21-2.06) and other races (aOR 1.65, 95% CI 1.41-2.41, reference White), liver disease (aOR 1.51, 95% CI 1.02-2.22), and median Charlson comorbidity score or higher (aOR 1.36, 95% CI 1.08-1.71, reference less than median). Clinical outcomes were similar between patients infected with sulfamethoxazole/trimethoprim-resistant, levofloxacin-resistant, and multidrug-resistant S. maltophilia strains compared to non-resistant strains.

CONCLUSIONS

In our national cohort of hospitalized patients with S. maltophilia infection, 13.7% of patients died during admission and several predictors of inpatient mortality were identified. Predictors related to the severity of infection were among the strongest identified. It is important that in severely ill patients presenting to the hospital, S. maltophilia be considered as a cause.

651. Ceftazidime/avibactam utilization in the national Veterans Affairs (VA) Healthcare System

Background

Multidrug-resistant infections are challenging to treat, due to underlying patient conditions, pathogen characteristics, and high resistance rates to antibiotic treatments. Ceftazidime/avibactam (CAZ-AVI, approved in 2015) is approved to treat complicated intra-abdominal infections, complicated urinary tract infections, hospital-acquired bacterial pneumonia, and ventilator-associated bacterial pneumonia. As newer antibiotic therapies come to market, limited data exist about their use in real-world practice. Therefore, we sought to describe the utilization of CAZ-AVI in clinical practice.

Methods

This national retrospective cohort study included hospitalized VA patients receiving CAZ-AVI from 2015 through 2021. Cultures, infection diagnoses, demographics, comorbidities, treatments, and clinical outcomes were assessed in this cohort.

Results

During the study period, 1,048 unique patients received CAZ-AVI, with a mean age of 71.5 (±11.9) years. The study cohort was predominantly male (98.3%) and White (66.2%, Black 27.7%). The most common organism-culture site combinations were Klebsiella-urine (19.6%), Pseudomonas aeruginosa-respiratory (14.0%), Pseudomonas aeruginosa-urine (10.1%), Escherichia coli-urine (6.9%) and Klebsiella-blood (6.9%). The median time to CAZ-AVI initiation from admission was 6 days, with a subsequent median 14-day hospital stay. Median length of CAZ-AVI therapy was 8 days. Most patients changed antibiotic therapy 3 times before starting CAZ-AVI. Treatment heterogeneity was high both prior to CAZ-AVI initiation (89.6%) and during CAZ-AVI treatment (85.6%). The most common concomitant antibiotic therapies during CAZ-AVI treatment were vancomycin (41.4%), meropenem (24.1%), cefepime (15.2%), and piperacillin/tazobactam (15.2%). Inpatient mortality in this cohort was 23.6%, and about one-third of patients had a subsequent hospitalization with CAZ-AVI treatment (35.1% in 2021).

Conclusion

Utilization of CAZ-AVI increased from 2015 to 2018 and has since stabilized in the national VA Healthcare System. CAZ-AVI has been utilized in complex, difficult-to-treat patients with substantial treatment heterogeneity and variation in causative organism-culture site.

Disclosures

Aisling R. Caffrey, PhD, M.S., AbbVie Inc.: Grant/Research Support|Gilead Sciences Inc.: Grant/Research Support|Merck & Co., Inc: Advisor/Consultant|Merck & Co., Inc: Grant/Research Support|Shionogi Inc.: Grant/Research Support Haley J. Appaneal, PharmD, Ph.D., Shionogi Inc: Grant/Research Support Kerry L. LaPlante, Pharm.D., FCCP, FIDSA, FIDP, AbbVie Inc.: Grant/Research Support|Gilead Sciences, Inc.: Grant/Research Support|Melinta Therapeutics, Inc.,: Grant/Research Support|Merck & Co., Inc.: Advisor/Consultant|Merck & Co., Inc.: Grant/Research Support|Nabriva Therapeutics US, Inc.,: Grant/Research Support|Ocean Spray Cranberries, Inc.: Grant/Research Support|Pfizer Pharmaceuticals: Grant/Research Support|Shionogi, Inc.: Grant/Research Support|Tetraphase Pharmaceuticals.: Grant/Research Support.

671. Relevance of Levofloxacin-Resistant MRSA and hVISA when utilizing directed antibiotic locks to treat stage 4 biofilm bone and joint infections

Background

Directed antibiotic locks have the potential to treat orthopedic infections due to the ability to bypass specific systemic absorption allowing for higher antimicrobial concentrations. With limiting antimicrobial options to treat biofilm commonly associated with bone and joint infections, our aim is to understand and further test the relevance of utilizing standard systemic MIC values to direct therapy.

Methods

Using our previously described biofilm assay with six unique spa-type (t004, t018, t062, t064, t1340, t008) MRSA isolates, biofilm was grown for 4, 6, and 24hrs at 6 log10 CFU/mL in TSB per CLSI guidance adding dextrose 1.25% for biofilm promotion. MIC were run using CLSI guidance. Planktonic cells were removed by irrigation, simulating debridement. 24hr treatment assays, simulating antibiotic locks included levofloxacin (5 mg/mL) in d5W solution and vancomycin (5 mg/mL) in NS.

Results

Levofloxacin by definition of standard MIC values was found to be resistant in five out of the six MRSA isolates (MIC ranging from 1 – 312mcg.mL). However, at 16-25,000 times the MIC, levofloxacin demonstrated a decrease in biofilm growth on mature 24-hr established biofilm by 9-130%. Similarly, vancomycin heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA), at 3000-6000 the MIC demonstrated a decrease of 53-190% mature biofilm growth.

Conclusion

All isolates produced consistent biofilm as previously tested as a low or high biofilm-producer when there was no antibiotic present. Levofloxacin and vancomycin at least 1000X the MIC nearly eradicated all established MRSA biofilm. Our next steps will be to evaluate if the MIC values have any effect on additional antibiotics in a lock solution.

Disclosures

Kerry L. LaPlante, Pharm.D., FCCP, FIDSA, FIDP, AbbVie Inc.: Grant/Research Support|Gilead Sciences, Inc.: Grant/Research Support|Melinta Therapeutics, Inc.,: Grant/Research Support|Merck & Co., Inc.: Advisor/Consultant|Merck & Co., Inc.: Grant/Research Support|Nabriva Therapeutics US, Inc.,: Grant/Research Support|Ocean Spray Cranberries, Inc.: Grant/Research Support|Pfizer Pharmaceuticals: Grant/Research Support|Shionogi, Inc.: Grant/Research Support|Tetraphase Pharmaceuticals.: Grant/Research Support.

Re-establishing the utility of tetracycline-class antibiotics for current challenges with antibiotic resistance

The progressive increase in antibiotic resistance in recent decades calls for urgent development of new antibiotics and antibiotic stewardship programs to help select appropriate treatments with the goal of minimising further emergence of resistance and to optimise clinical outcomes. Three new tetracycline-class antibiotics, eravacycline, omadacycline, and tigecycline, have been approved within the past 15 years, and represent a new era in the use of tetracyclines. These drugs overcome the two main mechanisms of acquired tetracycline-class resistance and exhibit a broad spectrum of in vitro activity against gram-positive, gram-negative, anaerobic, and atypical pathogens, including many drug-resistant strains. We provide an overview of the three generations of tetracycline-class drugs, focussing on the efficacy, safety, and clinical utility of these three new third-generation tetracycline-class drugs. We also consider various scenarios of unmet clinical needs where patients might benefit from re-engagement with tetracycline-class antibiotics including outpatient treatment options, patients with known β-lactam antibiotic allergy, reducing the risk of Clostridioides difficile infection, and their potential as monotherapy in polymicrobial infections while minimising the risk of any potential drug-drug interaction. KEY MESSAGESThe long-standing safety profile and broad spectrum of activity of tetracycline-class antibiotics made them a popular choice for treatment of various bacterial infections; unfortunately, antimicrobial resistance has limited the utility of the early-generation tetracycline agents.The latest generation of tetracycline-class antibiotics, including eravacycline, tigecycline, and omadacycline, overcomes the most common acquired tetracycline resistance mechanisms.Based on in vitro characteristics and clinical data, these newer tetracycline agents provide an effective antibiotic option in the treatment of approved indications in patients with unmet clinical needs - including patients with severe penicillin allergy, with renal or hepatic insufficiency, recent Clostridioides difficile infection, or polymicrobial infections, and those at risk of drug-drug interactions.

Trends in Stenotrophomonas maltophilia antibiotic resistance rates in the United States Veterans Affairs Health System

Introduction. Stenotrophomonas maltophilia is an important multidrug-resistant Gram-negative pathogen. While largely a hospital-acquired pathogen, there have been increasing reports of the pathogen in the community.

Gap Statement. Trends in S. maltophilia prevalence and resistance rates that include outpatient isolates are unknown.

Aim. We described recent trends in prevalence and resistance of S. maltophilia in the national Veterans Affairs (VA) Healthcare system.

Methodology. The study identified positive S. maltophilia clinical cultures among VA adult patients from 2010 to 2018 across all VA hospitals, long-term care facilities/units, and outpatient settings. Annual S. maltophilia resistance rates were evaluated. Multidrug resistant (MDR) was defined as resistance to sulfamethoxazole/trimethoprim (SMX/TMP) and minocycline or levofloxacin. Time trends were assessed with regression analyses to estimate annual average percent changes (AAPC) with 95 % confidence intervals using Joinpoint software.

Results. Over the 9 year study period, 18 285  S . maltophilia cultures were identified (57 % hospital, 3 % long-term care, 40 % outpatient). The most common source of S. maltophilia cultures were respiratory cultures (34.6 %) followed by urine cultures (30.4 %). In VA hospitals and long-term care facilities, the number of S. maltophilia cultures decreased significantly (by 5.4% and 8.4 % per year respectively). Overall, 3.1 % of isolates were MDR which remained stable over the study period. Resistance to other antibiotics assessed mostly remained stable, except SMX/TMP resistance decreased significantly by 8.5 % (2010, 15 %; 2018, 6 %) per year in VA hospitals.

Conclusion. While previous work has recognized S. maltophilia as primarily a nosocomial pathogen, the present study found that 40 % of cultures collected were among outpatients. Between 2010 and 2018, the number of positive S. maltophilia cultures decreased significantly in the national VA Healthcare System. Resistance to SMX/TMP decreased over the study period in VA hospitals and now more closely reflects previously reported resistance rates worldwide (0–10 %). MDR S. maltophilia remained stable and low in the national VA Healthcare System.

Assessing Rates of Co-Resistance and Patient Outcomes in Multidrug-Resistant Pseudomonas aeruginosa

Multidrug-resistant (MDR) Pseudomonas aeruginosa infections are associated with poor patient outcomes due to complex co-resistance patterns. We described common co-resistance patterns, clinical characteristics, and associated outcomes in patients admitted with an MDR P. aeruginosa. This national, multicenter, retrospective cohort study within the Veterans Affairs included adults hospitalized with a MDR P. aeruginosa infection (January 2015-December 2020) per Centers for Disease Control definition. Clinical outcomes were compared among those with differing MDR P. aeruginosa co-resistance: resistant to carbapenems and extended-spectrum cephalosporins and piperacillin-tazobactam (CARB/ESC/PT) versus without CARB/ESC/PT resistance; resistant to carbapenems and extended-spectrum cephalosporins and fluoroquinolone (CARB/ESC/FQ) versus without CARB/ESC/FQ resistance. We included 3,763 hospitalized patients. Co-resistance to CARB/ESC/PT was observed in 42.7%, and to CARB/ESC/FQ in 40.7%. The lowest co-resistance rates were observed with ceftolozane-tazobactam (6.2%, n = 6/97; 12.5%, n = 10/80, respectively) and ceftazidime-avibactam (5.2%, n = 5/97; 12.5%, n = 10/80, respectively). Overall, 14.2% of patients died during hospitalization, 59.7% had an extended length of stay, and 14.9% had reinfection with hospitalization. Outcomes were similar between patients with MDR P. aeruginosa strains with and without co-resistance to CARB/ESC/PT and CARB/ESC/FQ. Among a national cohort of patients hospitalized with MDR P. aeruginosa infections, co-resistance to three classes of standard of care antibiotics, such as carbapenem, extended-spectrum cephalosporins, and piperacillin-tazobactam or fluoroquinolones, exceeded 40% in our study population, posing great concerns for selecting appropriate empirical therapy. Clinical outcomes were poor for all patients, regardless of different co-resistance patterns. New treatment options are needed for hospitalized patients with suspected or confirmed MDR P. aeruginosa infections. IMPORTANCE We studied antibiotic co-resistance patterns in a national group of hospitalized patients with infections due to multidrug-resistant (MDR) Pseudomonas aeruginosa, a type of bacteria that resists treatment to at least three classes of antibiotics. Co-resistance to antibiotic classes most typically used for treatment was common, which makes selecting appropriate antibiotics to successfully treat the infections difficult. Outcomes, including death, were poor for all patients in our study, regardless of the different patterns of co-resistance to common antibiotic classes. New antibiotics are needed to help treat hospitalized patients with MDR P. aeruginosa infections.

Antimicrobial Prescribing in the Telehealth Setting: Framework for Stewardship During a Period of Rapid Acceleration Within Primary Care

Antibiotic resistance is a global public health threat. The use of telehealth in primary care presents unique barriers to antimicrobial stewardship, including limited physical examination and changes to the patient-provider relationship. Since the coronavirus disease 2019 (COVID-19) pandemic, there is a need to identify novel antimicrobial stewardship strategies with an explosion in the use of telehealth within primary care. Our review proposes a tailored, sustainable approach to antimicrobial prescribing in the telehealth setting based on the Centers for Disease Control and Prevention's Core Elements of Outpatient Antibiotic Stewardship: commitment, action for policy and practice; tracking and reporting; and education and expertise. The rapid growth of telehealth for all types of primary care visits (not just antibiotic use) is outpacing knowledge associated with strategies for antimicrobial stewardship. Improving antibiotic use within primary care settings is critical as telehealth will remain a priority whether the COVID-19 pandemic recedes, particularly within patient populations with limited access to healthcare.

It's about the patients: Practical antibiotic stewardship in outpatient settings in the United States

Antibiotic-resistant pathogens cause over 35,000 preventable deaths in the United States every year, and multiple strategies could decrease morbidity and mortality. As antibiotic stewardship requirements are being deployed for the outpatient setting, community providers are facing systematic challenges in implementing stewardship programs. Given that the vast majority of antibiotics are prescribed in the outpatient setting, there are endless opportunities to make a smart and informed choice when prescribing and to move the needle on antibiotic stewardship. Antibiotic stewardship in the community, or "smart prescribing" as we suggest, should factor in antibiotic efficacy, safety, local resistance rates, and overall cost, in addition to patient-specific factors and disease presentation, to arrive at an appropriate therapy. Here, we discuss some of the challenges, such as patient/parent pressure to prescribe, lack of data or resources for implementation, and a disconnect between guidelines and real-world practice, among others. We have assembled an easy-to-use best practice guide for providers in the outpatient setting who lack the time or resources to develop a plan or consult lengthy guidelines. We provide specific suggestions for antibiotic prescribing that align real-world clinical practice with best practices for antibiotic stewardship for two of the most common bacterial infections seen in the outpatient setting: community-acquired pneumonia and skin and soft-tissue infection. In addition, we discuss many ways that community providers, payors, and regulatory bodies can make antibiotic stewardship easier to implement and more streamlined in the outpatient setting.

The Comparative Effectiveness of Ceftolozane/Tazobactam versus Aminoglycoside- or Polymyxin-Based Regimens in Multi-Drug-Resistant Pseudomonas aeruginosa Infections

Pseudomonas aeruginosa infections are challenging to treat due to multi-drug resistance (MDR) and the complexity of the patients affected by these serious infections. As new antibiotic therapies come on the market, limited data exist about the effectiveness of such treatments in clinical practice. In this comparative effectiveness study of ceftolozane/tazobactam versus aminoglycoside- or polymyxin-based therapies among hospitalized patients with positive MDR P. aeruginosa cultures, we identified 57 patients treated with ceftolozane/tazobactam compared with 155 patients treated with aminoglycoside- or polymyxin-based regimens. Patients treated with ceftolozane/tazobactam were younger (mean age 67.5 vs. 71.1, p = 0.03) and had a higher comorbidity burden prior to hospitalization (median Charlson 5 vs. 3, p = 0.01) as well as higher rates of spinal cord injury (38.6% vs. 21.9%, p = 0.02) and P. aeruginosa-positive bone/joint cultures (12.3% vs. 0.7%, p < 0.0001). Inpatient mortality was significantly lower in the ceftolozane/tazobactam group compared with aminoglycosides or polymyxins (15.8% vs. 27.7%, adjusted odds ratio 0.39, 95% confidence interval 0.16−0.93). There were no significant differences observed for the other outcomes assessed. In hospitalized patients with MDR P. aeruginosa, inpatient mortality was 61% lower among patients treated with ceftolozane/tazobactam compared to those treated with aminoglycoside- or polymyxin-based regimens.

National trends in hospital, long-term care and outpatient Acinetobacter baumannii resistance rates

Introduction. Acinetobacter baumannii is a top-priority pathogen of the World Health Organization (WHO) and the Centers for Disease Control (CDC) due to antibiotic resistance.Gap Statement. Trends in A. baumannii resistance rates that include community isolates are unknown.Aim. Identify trends in A. baumannii resistance rates across the Veterans Affairs (VA) Healthcare System, including isolates from patients treated in hospitals, long-term care facilities and outpatient clinics nationally.Methodology. We included A. baumannii clinical cultures collected from VA patients from 2010 to 2018. Cultures were categorized by location: VA medical centers (VAMCs), long-term care (LTC) units [community living centers (CLCs)], or outpatient. We assessed carbapenem resistance, multidrug resistance (MDR) and extensive drug resistance (XDR). Time trends were assessed with Joinpoint regression.Results. We identified 19 376 A. baumannii cultures (53% VAMCs, 4% CLCs, 43% outpatient). Respiratory cultures were the most common source of carbapenem-resistant (43 %), multidrug-resistant (49 %) and extensively drug-resistant (21 %) isolates. Over the study period, the number of A. baumannii cultures decreased significantly in VAMCs (11.9% per year). In 2018, carbapenem resistance was seen in 28% of VAMC isolates and 36% of CLC isolates, but only 6% of outpatient isolates, while MDR was found in 31% of VAMC isolates and 36% of CLC isolates, but only 8 % of outpatient isolates. Carbapenem-resistant, multidrug-resistant and extensively drug-resistant A. baumannii isolates decreased significantly in VAMCs and outpatient clinics over time (VAMCs: by 4.9, 7.2 and 6.9%; outpatient: by 11.3, 10.5 and 10.2% per year). Resistant phenotypes remained stable in CLCs.Conclusion. In the VA nationally, the prevalence of A. baumannii is decreasing, as is resistance. Carbapenem-resistant and multidrug-resistant A. baumannii remain common in VAMCs and CLCs. The focus of infection control and antimicrobial stewardship efforts to prevent transmission of resistant A. baumannii should be in hospital and LTC settings.

Antimicrobial Stewardship and the Infection Control Practitioner: A Natural Alliance

Antibiotic overuse and misuse has contributed to rising rates of multidrug-resistant organisms and Clostridioides difficile. Decreasing antibiotic misuse has become a national public health priority. This review outlines the goals of antimicrobial stewardship, essential members of the program, implementation strategies, approaches to measuring the program's impact, and steps needed to build a program. Highlighted is the alliance between antimicrobial stewardship programs and infection prevention programs in their efforts to improve antibiotic use, improve diagnostic stewardship for C difficile and asymptomatic bacteriuria, and decrease health care-associated infections and the spread of multidrug-resistant organisms.

Poor clinical outcomes associated with suboptimal antibiotic treatment among older long-term care facility residents with urinary tract infection: a retrospective cohort study

BACKGROUND

Antibiotic use is associated with several antibiotic-related harms in vulnerable, older long-term care (LTC) residents. Suboptimal antibiotic use may also be associated with harms but has not yet been investigated. The aim of this work was to compare rates of poor clinical outcomes among LTC residents with UTI receiving suboptimal versus optimal antibiotic treatment.

METHODS

We conducted a retrospective cohort study among residents with an incident urinary tract infection (UTI) treated in Veterans Affairs LTC units (2013-2018). Potentially suboptimal antibiotic treatment was defined as use of a suboptimal initial antibiotic drug choice, dose frequency, and/or excessive treatment duration. The primary outcome was time to a composite measure of poor clinical outcome, defined as UTI recurrence, acute care hospitalization/emergency department visit, adverse drug event, Clostridioides difficile infection (CDI), or death within 30 days of antibiotic discontinuation. Shared frailty Cox proportional hazard regression models were used to compare the time-to-event between suboptimal and optimal treatment.

RESULTS

Among 19,701 LTC residents with an incident UTI, 64.6% received potentially suboptimal antibiotic treatment and 35.4% experienced a poor clinical outcome. In adjusted analyses, potentially suboptimal antibiotic treatment was associated with a small increased hazard of poor clinical outcome (aHR 1.06, 95% CI 1.01-1.11) as compared with optimal treatment, driven by an increased hazard of CDI (aHR 1.94, 95% CI 1.54-2.44).

CONCLUSION

In this national cohort study, suboptimal antibiotic treatment was associated with a 6% increased risk of the composite measure of poor clinical outcomes, in particular, a 94% increased risk of CDI. Beyond the decision to use antibiotics, clinicians should also consider the potential harms of suboptimal treatment choices with regards to drug type, dose frequency, and duration used.

Identification of a bacteria-produced benzisoxazole with antibiotic activity against multi-drug resistant Acinetobacter baumannii

The emergence of multi-drug resistant pathogenic bacteria represents a serious and growing threat to national healthcare systems. Most pressing is an immediate need for the development of novel antibacterial agents to treat Gram-negative multi-drug resistant infections, including the opportunistic, hospital-derived pathogen, Acinetobacter baumannii. Herein we report a naturally occurring 1,2-benzisoxazole with minimum inhibitory concentrations as low as 6.25 μg ml-1 against clinical strains of multi-drug resistant A. baumannii and investigate its possible mechanisms of action. This molecule represents a new chemotype for antibacterial agents against A. baumannii and is easily accessed in two steps via de novo synthesis. In vitro testing of structural analogs suggest that the natural compound may already be optimized for activity against this pathogen. Our results demonstrate that supplementation of 4-hydroxybenzoate in minimal media was able to reverse 1,2-benzisoxazole's antibacterial effects in A. baumannii. A search of metabolic pathways involving 4-hydroxybenzoate coupled with molecular modeling studies implicates two enzymes, chorismate pyruvate-lyase and 4-hydroxybenzoate octaprenyltransferase, as promising leads for the target of 3,6-dihydroxy-1,2-benzisoxazole.

Towards precision medicine: Therapeutic drug monitoring-guided dosing of vancomycin and β-lactam antibiotics to maximize effectiveness and minimize toxicity

PURPOSE

The goal of this review is to explore the role of antimicrobial therapeutic drug monitoring (TDM), especially in critically ill, obese, and older adults, with a specific focus on β-lactams and vancomycin.

SUMMARY

The continued rise of antimicrobial resistance prompts the need to optimize antimicrobial dosing. The aim of TDM is to individualize antimicrobial dosing to achieve antibiotic exposures associated with improved patient outcomes. Initially, TDM was developed to minimize adverse effects during use of narrow therapeutic index agents. Today, patient and organism complexity are expanding the need for precision dosing through TDM services. Alterations of pharmacokinetics and pharmacodynamics (PK/PD) in the critically ill, obese, and older adult populations, in conjunction with declining organism susceptibility, complicate attainment of therapeutic targets. Over the last decade, antimicrobial TDM has expanded with the emergence of literature supporting β-lactam TDM and a shift from monitoring vancomycin trough concentrations to monitoring of the ratio of area under the concentration (AUC) curve to minimum inhibitory concentration (MIC). PK/PD experts should be at the forefront of implementing precision dosing practices.

CONCLUSION

Precision dosing through TDM is expanding and is especially important in populations with altered PK/PD, including critically ill, obese, and older adults. Due to wide PK/PD variability in these populations, TDM is vital to maximize antimicrobial effectiveness and decrease adverse event rates. However, there is still a need for studies connecting TDM to patient outcomes. Providing patient-specific care through β-lactam TDM and transitioning to vancomycin AUC/MIC monitoring may be challenging, but with experts at the forefront of this initiative, PK-based optimization of antimicrobial therapy can be achieved.

Predictors of potentially suboptimal treatment of urinary tract infections in long-term care facilities

BACKGROUND

Suboptimal antibiotic treatment of urinary tract infection (UTI) is high in long-term care facilities (LTCFs) and likely varies between facilities. Large-scale evaluations have not been conducted.

AIM

To identify facility-level predictors of potentially suboptimal treatment of UTI in Veterans Affairs (VA) LTCFs and to quantify variation across facilities.

METHODS

This was a retrospective cohort study of 21,938 residents in 120 VA LTCFs (2013-2018) known as Community Living Centers (CLCs). Potentially suboptimal treatment was assessed from drug choice, dose frequency, and/or treatment duration. To identify facility characteristics predictive of suboptimal UTI treatment, LTCFs with higher and lower rates of suboptimal treatment (≥median, < median) were compared using unconditional logistic regression models. Joinpoint regression models were used to quantify average percentage difference across facilities. Multilevel logistic regression models were used to quantify variation across facilities.

FINDINGS

The rate of potentially suboptimal antibiotic treatment varied from 1.7 to 34.2 per 10,000 bed-days across LTCFs. The average percentage difference in rates across facilities was 2.5% (95% confidence interval (CI): 2.4-2.7). The only facility characteristic predictive of suboptimal treatment was the incident rate of UTI per 10,000 bed-days (odds ratio: 4.9; 95% CI: 2.3-10.3). Multilevel models demonstrated that 94% of the variation between facilities was unexplained after controlling for resident and CLC characteristics. The median odds ratio for the full multilevel model was 1.37.

CONCLUSION

Potentially suboptimal UTI treatment was variable across VA LTCFs. However, most of the variation across LTCFs was unexplained. Future research should continue to investigate factors that are driving suboptimal antibiotic treatment in LTCFs.

Evaluation of post-flexible cystoscopy urinary tract infection rates

PURPOSE

The risk of urinary tract infection (UTI) development after flexible cystoscopy (FC) is not well described. It remains difficult to assess the role of pre-FC antimicrobial prophylaxis to reduce UTI risk.

METHODS

In fall 2017, the urology service at the Providence Veterans Affairs Medical Center implemented routine oral antimicrobial prophylaxis in its outpatient FC clinic. Outpatients were randomly selected for a retrospective chart review to compare patients who received pre-FC antimicrobials (cefuroxime 500 mg tablet or sulfamethoxazole/trimethoprim [800 mg/160 mg] tablet) and those who underwent FC prior to fall 2017 and did not receive prophylaxis. The primary outcome was presence of symptomatic UTI within 30 days post FC. Secondary outcomes included symptomatic UTI that met colony-forming unit (CFU)/mL guideline requirements, and UTI treatment received. Potential risk factors for UTI were also assessed.

RESULTS

A total of 296 patients were included in the final analysis: 139 who did not receive and 157 who received a prophylactic antimicrobial before FC. Rates of symptomatic UTI, symptomatic UTI meeting CFU/mL guideline requirements, and postprocedure treatment for UTI were similar with and without antimicrobial prophylaxis (2.5% vs 2.2% [P > 0.99], 1.9% vs 1.4% [P > 0.99], and 2.5% vs 4.3% [P = 0.53], respectively). The mean number of days from FC to the start of UTI treatment was 7.9 (range, 1-18 days). Age over 65 years was the only risk factor present in all patients with a post-FC UTI, irrespective of antimicrobial prophylaxis.

CONCLUSION

The rate of post-FC symptomatic UTI was lower than rates previously described in the literature. The role of antimicrobial prophylaxis prior to FC warrants further exploration.

What Is the Role for Metronidazole in the Treatment of Clostridium difficile Infection? Results From a National Cohort Study of Veterans With Initial Mild Disease

BACKGROUND

Metronidazole may still be an appropriate therapeutic option for mild Clostridium difficile infection (CDI) in select patients, but data are limited to guide clinicians in identifying these patients.

METHODS

Our 2-stage study included a national cohort of Veterans with a first episode of mild CDI (2010-2014). First, among those treated with metronidazole, we identified predictors of success, defined as absence of all-cause mortality or recurrence 30 days posttreatment, using multivariable unconditional logistic regression. Second, among a subgroup of patients with characteristics predictive of success identified in the first stage, we compared clinical outcomes among those treated with metronidazole compared with vancomycin, using Cox proportional hazards models for time to 30-day all-cause mortality, CDI recurrence, and failure.

RESULTS

Among 3656 patients treated with metronidazole, we identified 3282 patients with success and 374 patients without success (failure). Younger age was the only independent predictor of success. Age ≤65 years was associated with an odds of success 1.63 times higher (95% confidence interval [CI], 1.29-2.06) than age >65 years. Among 115 propensity score-matched pairs ≤65 years of age, no significant differences were observed between metronidazole and vancomycin (reference) for all-cause mortality (hazard ratio [HR], 0.29 [95% CI, .06-1.38]), CDI recurrence (HR, 0.62 [95% CI, .26-1.49]), or failure (HR, 0.50 [95% CI, .23-1.07]).

CONCLUSIONS

Among patients ≤65 years of age with initial mild CDI, clinical outcomes were similar with metronidazole and vancomycin. These data suggest that metronidazole may be considered for the treatment of initial mild CDI among patients 65 years of age or younger.

Frequency and Predictors of Suboptimal Prescribing Among a Cohort of Older Male Residents with Urinary Tract Infection

BACKGROUND

Unnecessary antibiotic treatment of suspected urinary tract infection (UTI) is common in long-term care facilities (LTCFs). However, less is known about the extent of suboptimal treatment, in terms of antibiotic choice, dose, and duration, after the decision to use antibiotics has been made.

METHODS

We described the frequency of potentially suboptimal treatment among residents with an incident UTI (first during the study with none in the year prior) in Veterans Affairs' (VA) Community Living Centers (CLCs, 2013-2018). Time trends were analyzed using Joinpoint regression. Residents with UTIs receiving potentially suboptimal treatment were compared to those receiving optimal treatment to identify resident characteristics predictive of suboptimal antibiotic treatment, using multivariable unconditional logistic regression models.

RESULTS

We identified 21,938 residents with an incident UTI treated in 120 VA CLCs, of which 96.0% were male. Potentially suboptimal antibiotic treatment was identified in 65.0% of residents and decreased 1.8% annually (p<0.05). Potentially suboptimal initial drug choice was identified in 45.6% of residents, suboptimal dose frequency in 28.6%, and longer than recommended duration in 12.7%. Predictors of suboptimal antibiotic treatment included: prior fluoroquinolone exposure (adjusted odds ratio [aOR] 1.38), chronic renal disease (aOR 1.19), age >85 years (aOR 1.17), prior skin infection (aOR 1.14), recent high white blood cell count (aOR 1.08), and genitourinary disorder (aOR 1.08).

CONCLUSION

Similar to findings in non-VA facilities, potentially suboptimal treatment was common but improving in CLC residents with an incident UTI. Predictors of suboptimal antibiotic treatment should be targeted with antibiotic stewardship interventions to improve UTI treatment.

Delay in Antibiotic Administration Is Associated With Mortality Among Septic Shock Patients With Staphylococcus aureus Bacteremia

OBJECTIVES

The relationship between the timing of antibiotics and mortality among septic shock patients has not been examined among patients specifically with Staphylococcus aureus bacteremia.

DESIGN

Retrospective analysis of a Veterans Affairs S. aureus bacteremia database.

SETTING

One-hundred twenty-two hospitals in the Veterans Affairs Health System.

PATIENTS

Patients with septic shock and S. aureus bacteremia admitted directly from the emergency department to the ICU from January 1, 2003, to October 1, 2015, were evaluated.

INTERVENTIONS

Time to appropriate antibiotic administration and 30-day mortality.

MEASUREMENTS AND MAIN RESULTS

A total of 506 patients with S. aureus bacteremia and septic shock were included in the analysis. Thirty-day mortality was 78.1% for the entire cohort and was similar for those participants with methicillin-resistant S. aureus and methicillin-sensitive S. aureus bacteremia. Our multivariate analysis revealed that, as compared with those who received appropriate antibiotics within 1 hour after emergency department presentation, each additional hour that passed before appropriate antibiotics were administered produced an odds ratio of 1.11 (95% CI, 1.02-1.21) of mortality within 30 days. This odds increase equates to an average adjusted mortality increase of 1.3% (95% CI, 0.4-2.2%) for every hour that passes before antibiotics are administered.

CONCLUSIONS

The results of this study further support the importance of prompt appropriate antibiotic administration for patients with septic shock. Physicians should consider acting quickly to administer antibiotics with S. aureus coverage to any patient suspected of having septic shock.

Predictors of Clostridioides difficile recurrence across a national cohort of veterans in outpatient, acute, and long-term care settings

PURPOSE

The greatest challenge in treating Clostridioides difficile infection (CDI) is disease recurrence, which occurs in about 20% of patients, usually within 30 days of treatment cessation. We sought to identify independent predictors of first recurrence among a national cohort of veterans with CDI.

METHODS

We conducted a case-control study among acute and long-term care Veterans Affairs (VA) inpatients and outpatients with a first CDI episode (positive stool sample for C. difficile toxin[s] and receipt of at least 2 days of CDI treatment) between 2010 and 2014. Cases experienced first recurrence within 30 days from the end of treatment. Controls were those without first recurrence matched 4:1 to cases on year, facility, and severity. Multivariable conditional logistic regression was used to identify predictors of first recurrence.

RESULTS

We identified 32 predictors of first recurrence among 974 cases and 3,896 matched controls. Significant predictors included medication use prior to (probiotics, fluoroquinolones, laxatives, third- or fourth-generation cephalosporins), during (first- or second-generation cephalosporins, penicillin/amoxicillin/ampicillin, third- and fourth-generation cephalosporins), and after CDI treatment (probiotics, any antibiotic, proton pump inhibitors [PPIs], and immunosuppressants). Other predictors included current biliary tract disease, malaise/fatigue, cellulitis/abscess, solid organ cancer, medical history of HIV, multiple myeloma, abdominal pain, and ulcerative colitis.

CONCLUSION

In a large national cohort of outpatient and acute and long-term care inpatients, treatment with certain antibiotics, PPIs, immunosuppressants, and underlying disease were among the most important risk factors for first CDI recurrence.

A Review of Combination Antimicrobial Therapy for Enterococcus faecalis Bloodstream Infections and Infective Endocarditis

Enterococci, one of the most common causes of hospital-associated infections, are responsible for substantial morbidity and mortality. Enterococcus faecalis, the more common and virulent species, causes serious high-inoculum infections, namely infective endocarditis, that are associated with cardiac surgery and mortality rates that remained unchanged for the last 30 years. The best cures for these infections are observed with combination antibiotic therapy; however, optimal treatment has not been fully elucidated. It is the purpose of this review to highlight treatment options and their limitations, and provide direction for future investigative efforts to aid in the treatment of these severe infections. While ampicillin plus ceftriaxone has emerged as a preferred treatment option, mortality rates continue to be high, and from a safety standpoint, ceftriaxone, unlike other cephalosporins, promotes colonization with vancomycin resistant-enterococci due to high biliary concentrations. More research is needed to improve patient outcomes from this high-mortality disease.

Antibiograms Cannot Be Used Interchangeably Between Acute Care Medical Centers and Affiliated Nursing Homes

OBJECTIVE

To determine whether antibiograms for Veterans Affairs (VA) nursing homes (NHs), termed Community Living Centers, are similar to those from their affiliated acute care medical centers.

DESIGN

Descriptive study.

SETTING AND PARTICIPANTS

We compared the 2017 antibiograms for VA NHs to their affiliated VA medical centers (VAMCs). Antibiograms included antibiotic susceptibility rates for commonly observed bacteria in this setting (Staphylococcus aureus, Enterococcus spp, Escherichia coli, Klebsiella spp, Proteus mirabilis, and Pseudomonas aeruginosa).

METHODS

Antibiograms were considered to be in complete agreement when the overall susceptibility rate between the NH and affiliated VAMC was either at or above 80% or below 80% across all bacteria and antibiotics. Average percentage of bacteria-antibiotic comparisons in disagreement per facility pair, and number of facilities with agreement for specific bacteria-antibiotic comparisons were also assessed. The chi-square test was used to compare disagreement between NH-VAMC facilities based on geographic proximity of the NH to the VAMC, culture source, and bed size.

RESULTS

A total of 119 NH-VAMC affiliate pairs were included in this analysis, with 71% (84/119) on the same campus and 29% (35/119) on geographically distinct campuses. None of the NH-VAMC pairs demonstrated complete agreement (all bacteria vs all antibiotics) between their antibiograms. On average, 20% of the bacteria-antibiotic comparisons from the antibiogram disagreed clinically per NH-VAMC pair, and almost twice as often the nursing home had lower susceptibility (higher resistance) than the acute care facility. Some bacteria-antibiotic comparisons agreed in all facilities (eg, E coli-imipenem; S aureus-linezolid; S aureus-vancomycin), while others showed greater disagreement (eg, Klebsiella spp-cefazolin; Klebsiella spp-ampicillin-sulbactam; P aeruginosa-ciprofloxacin). Rates of clinical disagreement were similar by geographic proximity of the NH to the VAMC, culture source, and bed size.

CONCLUSIONS AND IMPLICATIONS

Overall, this study showed a moderate lack of agreement between VA NH antibiograms and their affiliate VAMC antibiograms. Our data suggest that antibiograms of acute care facilities are often not accurate approximations of the nursing home resistance patterns and therefore should be used with caution (if at all) in guiding empiric antibiotic therapy.

Trends in Collection of Microbiological Cultures Across Veterans Affairs Community Living Centers in the United States Over 8 Years

OBJECTIVES

To describe and evaluate changes in the collection of microbiological cultures across Veterans Affairs (VA) Community Living Centers (CLCs) nationally.

DESIGN

Descriptive study.

SETTING

146 VA CLCs.

PARTICIPANTS

We identified both positive and negative microbiological cultures collected during VA CLC admissions from January 2010 through December 2017.

MEASURES

We measured the average annual percentage change (AAPC) in the rate of cultures collected per 1000 bed days and per admission, overall and stratified by culture type (ie, urine, blood, skin and soft tissue, and respiratory tract). AAPCs were also calculated for the proportion and rate of positive cultures collected, overall and stratified by culture type and organism (ie, Escherichia coli, Proteus mirabilis, Staphylococcus aureus, Enterococcus spp, Pseudomonas aeruginosa, Klebsiella spp, Enterobacter spp, Morganella morganii, Citrobacter spp, Serratia marcescens, and Streptococcus pneumoniae). Joinpoint regression software was used to assess trends and estimate AAPCs and 95% confidence intervals (CIs).

RESULTS

Over 8 years, 355,329 cultures were collected. The rate of cultures collected per 1000 bed days of care decreased significantly by 6.0% per year (95% CI -8.7%, -3.2%). The proportion of positive cultures decreased by 0.9% (95% CI -1.4%, -0.4%). The most common culture types were urine (48.4%), followed by blood (27.7%). The rate of cultures collected per 1000 bed days of care decreased per year by 6.3% for urine, 5.0% for blood, 4.4% for skin and soft tissue, and 4.9% for respiratory tract. In 2010, S aureus was the most common organism identified, and in all subsequent years E coli was the most common.

CONCLUSION AND IMPLICATIONS

We identified a significant reduction in the number of cultures collected over time among VA CLCs. Our findings may be explained by decreases in the collection of unnecessary cultures in VA CLCs nationally due to increased antibiotic stewardship efforts targeting unnecessary culturing and antibiotic treatment.

Weak biofilm formation among carbapenem-resistant Klebsiella pneumoniae

Biofilm formation of multidrug and extensively drug resistant Klebsiella pneumoniae isolates is poorly understood. We investigated 139 diverse clinical K. pneumoniae isolates that possess various resistance patterns to evaluate the relationship between biofilm formation and resistance. Antimicrobial resistance was compared among a diverse collection of weak versus strong biofilm-forming K. pneumoniae, and predictors of strong biofilm formation were identified. Multi-drug resistant isolates were more common among weak (97.9%) versus strong biofilm formers (76%; P = 0.002). Carbapenem-resistant K. pneumoniae were 91% less likely to form strong biofilm (odds ratio 0.09; 95% confidence interval 0.02-0.33). The statistically significant inverse relationship between biofilm formation and antibiotic resistance suggests that virulence may be a trade-off for survival.

A Review of Nonantibiotic Agents to Prevent Urinary Tract Infections in Older Women

OBJECTIVE

This article provides a comprehensive literature review on nonantibiotic agents used for the prevention of urinary tract infections (UTIs) in women ≥45 years of age.

DESIGN

A structured review was performed by conducting a literature search to identify relevant studies pertaining to the use of nonantibiotic agents to prevent UTIs in women who were perimenopausal through postmenopausal. Recommendations were made for or against the use of each nonantibiotic agent, unless data were unavailable. Levels of evidence were assigned to each recommendation made.

SETTING AND PARTICIPANTS

Studies on the prevention of UTIs with women subjects ≥45 years of age in the community, inpatient, and long-term care settings were considered for inclusion.

MEASURE

The efficacy and safety of using ascorbic acid, cranberry products, d-mannose, estrogens, lactobacilli, and methenamine hippurate for prevention of UTIs was assessed.

RESULTS

There is evidence to support use of estrogens (A-I) in postmenopausal women, and cranberry capsules (C-I) in women ≥45 years of age for the prevention of UTIs. There was a lack of evidence to make recommendations for or against the use of ascorbic acid, cranberry juice, cranberry capsules with high proanthocyanidin (PAC) content, d-mannose, lactobacillus, and methenamine hippurate in this population.

CONCLUSIONS/IMPLICATIONS

Current studies support that estrogens and cranberry capsules may have a role in preventing UTIs in women ≥45 years of age. Further research is needed to elucidate the role of these nonantibiotic agents and how they may be used to decrease antibiotic use.

Comparative Effectiveness of Exclusive Exposure to Nafcillin or Oxacillin, Cefazolin, Piperacillin/Tazobactam, and Fluoroquinolones Among a National Cohort of Veterans With Methicillin-Susceptible Staphylococcus aureus Bloodstream Infection

Objective

Beta-lactam antibiotics are recommended as first-line for treatment of methicillin-sensitive Staphylococcus aureus (MSSA) bacteremia. The objective of this study was to compare effectiveness of anti-MSSA therapies among bacteremia patients exclusively exposed to 1 antimicrobial.

Method

This was a national retrospective cohort study of patients hospitalized in Veterans Affairs medical centers with MSSA bacteremia from January 1, 2002, to October 1, 2015. Patients were included if they were treated exclusively with nafcillin, oxacillin, cefazolin, piperacillin/tazobactam, or fluoroquinolones (moxifloxacin and levofloxacin). We assessed 30-day mortality, time to discharge, inpatient mortality, 30-day readmission, and 30-day S. aureus reinfection. Hazard ratios (HRs) and 95% confidence intervals (CI) were calculated using propensity-score (PS) matched Cox proportional hazards regression model.

Results

When comparing nafcillin/oxacillin (n = 105) with cefazolin (n = 107), 30-day mortality was similar between groups (PS matched n = 44; HR, 0.67; 95% CI, 0.11-4.00), as were rates of the other outcomes assessed. As clinical outcomes did not vary between nafcillin/oxacillin and cefazolin, they were combined for comparison with piperacillin/tazobactam (n = 113) and fluoroquinolones (n = 103). Mortality in the 30 days after culture was significantly lower in the nafcillin/oxacillin/cefazolin group compared with piperacillin/tazobactam (PS matched n = 48; HR, 0.10; 95% CI, 0.01-0.78), and similar when compared with fluoroquinolones (PS matched n = 32; HR, 1.33; 95% CI, 0.30-5.96).

Conclusions

In hospitalized patients with MSSA bacteremia, no difference in mortality was observed between nafcillin/oxacillin and cefazolin or fluoroquinolones. However, higher mortality was observed with piperacillin/tazobactam as compared with nafcillin/oxacillin/cefazolin, suggesting it may not be as effective as a monotherapy in MSSA bacteremia.

Comparison of linezolid and vancomycin lock solutions with and without heparin against biofilm-producing bacteria

PURPOSE

The activity of linezolid and vancomycin lock solutions against biofilm-producing strains of Staphylococcus aureus, S. epidermidis, and Enterococcus faecalis was studied.

METHODS

Two strains each of methicillin-susceptible S. aureus (MSSA), methicillin-resistant S. aureus (MRSA), and S. epidermidis, and 1 strain of vancomycin-susceptible E. faecalis and vancomycin-resistant E. faecalis were tested against vancomycin and linezolid to assess prevention of biofilm formation and eradication of these pathogens within a formed biofilm. Activity was also tested in a 72-hour in vitro central venous catheter (CVC) model. After 24 hours of biofilm growth in a CVC, a lock solution containing vancomycin (2 or 5 mg/mL) or linezolid (1 or 2 mg/mL) alone or in combination with heparin sodium (5,000 units/mL with benzyl alcohol 0.45%) was instilled and incubated at 35 °C for 72 hr. Heparin and 0.9% sodium chloride injection were also tested.

RESULTS

Linezolid and vancomycin prevented biofilm formation below the minimum inhibitory concentration for 88% and 25% of isolates tested, respectively. The addition of preservative-containing heparin decreased the activity of vancomycin and linezolid lock solutions against all strains. Vancomycin 2- and 5-mg/mL lock solutions had the most activity against MSSA and E. faecalis strains (p < 0.01). Linezolid 2 mg/mL was the most active lock solution against the MRSA strains tested (p < 0.01). There were no significant differences in vancomycin or linezolid lock solution activity against S. epidermidis.

CONCLUSION

Heparin reduced activity of vancomycin and linezolid lock solutions against S. aureus, S. epidermidis, and E. faecalis biofilms. While linezolid or vancomycin lock solution reduced overall biofilm burden, it did not completely eradicate the bacteria at tested concentrations.

Heterogeneity in the treatment of bloodstream infections identified from antibiotic exposure mapping

Purpose

As changes in antibiotic therapy are common, intent‐to‐treat and definitive therapy exposure definitions in infectious disease clinical trials and observational studies may not accurately reflect all antibiotics received over the course of the infection. Therefore, we sought to describe changes in antibiotic therapy and unique treatment patterns among patients with bacteremia.

Methods

We conducted a retrospective cohort study of hospitalizations from Veterans Affairs (VA) Medical Centers (January 2002‐September 2015) and community hospitals (de‐identified Optum Clinformatics DataMart with matched Premier Hospital data; October 2009‐March 2013). In the VA population, antibiotic exposures were mapped from the culture collection date among those with positive Staphylococcus aureus cultures. In the Optum‐Premier population, exposures were mapped from the admission date among those with a primary diagnosis of bacteremia.

Results

Our study included 50 467 bacteremia admissions, with only 14% of admissions having the same treatment pattern as another admission. For every 100 bacteremia admissions, 89 had changes in antibiotic therapy. For every 100 bacteremia admissions with changes in therapy, 95 had unique antibiotic treatment patterns. These findings were consistent in both populations, over time, and among different facilities within study populations. The median time to first therapy change was 2 days after initial therapy, with a median of three changes.

Conclusions

Changes in antibiotic therapy for bloodstream infections were nearly universal regardless of hospital setting. Based on our findings, common antibiotic exposure definitions of intent‐to‐treat and definitive therapy would misclassify exposure in 86% of admissions, which highlights the need for better operational definitions of exposure in infectious diseases research.

Biofilm prevention concentrations (BPC) of minocycline compared to polymyxin B, meropenem, and amikacin against Acinetobacter baumannii

Infections caused by Acinetobacter baumannii are difficult to treat as they are often multidrug resistant (MDR) and frequently form biofilms. We investigated the activities of minocycline, polymyxin B, meropenem, and amikacin against diverse Acinetobacter baumannii strains with biofilm formation classified as weak versus moderate/strong. At clinically achievable concentrations, minocycline prevented biofilm formation for 96% of isolates versus 54% for polymyxin B, 29% for meropenem and 29% for amikacin. Minocycline and polymyxin B demonstrated highest in vitro activity against A. baumannii and prevented biofilm formation for a majority of isolates.

Improved survival with continuation of statins in bacteremic patients

Objectives:

Varying statin exposures in bacteremic patients have different impacts on mortality. Among patients with adherent statin use, we sought to evaluate the impact of statin continuation on inpatient mortality in bacteremic patients.

Methods:

A retrospective cohort study was conducted using Optum Clinformatics^TM with matched Premier Hospital data (October 2009–March 2013). Patients with a primary diagnosis of bacteremia and 6 months of continuous enrollment prior to the admission, receiving antibiotics at least 2 days of antibiotics during the first 3 days of admission, were selected for inclusion. Furthermore, patients demonstrating adherent statin use based on 90 days of continuous therapy prior to admission were included. We then compared those continuing statin therapy for at least the first 5 days after admission and those not continuing during the admission.

Results:

Simvastatin (53.2%) and atorvastatin (33.8%) were the most commonly used statins among the 633 patients who met our inclusion and exclusion criteria. Propensity score adjusted Cox proportional hazards regression models demonstrated significantly lower inpatient mortality among those continuing statin therapy compared with those not continuing (n = 232 vs 401, adjusted hazard ratio 0.25, 95% confidence interval 0.08–0.79).

Conclusion:

Among patients adherent to their statin therapy prior to a bacteremia hospitalization, continued statin use after admission increased survival by 75% compared with those not continuing.

Optimal duration for continuation of statin therapy in bacteremic patients

Background

Evidence suggests statins may improve survival in patients with bloodstream infections. However, there is no consensus on optimal timing and duration of exposure.

Objectives

To quantify statin therapy duration associated with decreased mortality in bacteremic statin users.

Methods

We conducted a case-control study using OptumClinformatics™ with matched Premier hospital data (1 October 2009-31 March 2013). Cases who died during the hospitalization were matched 1:1 to survivors on disease risk scores (DRSs). Post-admission statin therapy duration was evaluated in patients with at least 90 days of pre-admission continuous statin use. Classification and regression tree (CART) analysis was conducted to identify the optimal duration of statin continuation which provided the lowest inpatient mortality. Logistic regression was used to calculate the odds of mortality.

Results

We included 58 DRS matched pairs of cases and controls: 47 patients (41%) continued statin therapy during the hospital admission, 15 (32%) cases and 32 (68%) controls. The CART analysis partitioned the continuation of statin therapy at ⩾2 days, representing lower mortality for patients who continued statins for 2 days or more and higher mortality for patients who did not continue or remained on statins for only 1 day. Inpatient mortality was 76% lower among those with at least 2 days of continued statin use (odds ratio 0.24, 95% confidence interval 0.11-0.55).

Conclusion

Among matched cases and controls with at least 90 days of baseline statin use prior to the admission, the continuation of statins for at least 2 days after admission demonstrated a survival benefit among bacteremic patients.

Predictors of Mortality Among a National Cohort of Veterans With Recurrent Clostridium difficile Infection

Background

Though recurrent Clostridium difficile infection (CDI) is common and poses a major clinical concern, data are lacking regarding mortality among patients who survive their initial CDI and have subsequent recurrences. Risk factors for mortality in patients with recurrent CDI are largely unknown.

Methods

Veterans Affairs patients with a first CDI (stool sample with positive C. difficile toxin(s) and ≥2 days CDI treatment) were included (2010-2014). Subsequent recurrences were defined as additional CDI episodes ≥14 days after the stool test date and within 30 days of the end of treatment. A matched (1:4) case-control analysis was conducted using multivariable conditional logistic regression to identify predictors of all-cause mortality within 30 days of the first recurrence.

Results

Crude 30-day all-cause mortality rates were 10.6% for the initial CDI episode, 8.3% for the first recurrence, 4.2% for the second recurrence, and 5.9% for the third recurrence. Among 110 cases and 440 controls, 6 predictors of mortality were identified: use of proton pump inhibitors (PPIs; odds ratio [OR], 3.86; 95% confidence interval [CI], 2.14-6.96), any antibiotic (OR, 3.33; 95% CI, 1.79-6.17), respiratory failure (OR, 8.26; 95% CI, 1.71-39.92), congitive dysfunction (OR, 2.41; 95% CI, 1.02-5.72), nutrition deficiency (OR, 2.91; 95% CI, 1.37-6.21), and age (OR, 1.04; 95% CI, 1.01-1.07).

Conclusions

In our national cohort of Veterans, crude mortality decreased by 44% from the initial episode to the third recurrence. Treatment with antibiotics, use of PPIs, and underlying comorbidities were important predictors of mortality in recurrent CDI. Our study assists health care providers in identifying patients at high risk of death after CDI recurrence.

Nephrotoxicity With Vancomycin in the Pediatric Population: A Systematic Review and Meta-Analysis

BACKGROUND

Vancomycin is frequently used to treat methicillin-resistant Staphylococcus aureus infections in pediatric patients. Vancomycin exposure may lead to an increase in frequency of nephrotoxicity. Our aim was to conduct a systematic review to describe predictors of nephrotoxicity associated with vancomycin, including documented trough concentrations ≥15 mg/L. We also aimed to use a meta-analysis to assess the impact of a vancomycin trough ≥15 mg/L on nephrotoxicity.

METHODS

A literature search was performed using PubMed, Cochrane Library, Embase and Web of Sciences database. We included randomized clinical trials and observational studies evaluating the relationship between vancomycin troughs and nephrotoxicity in pediatric-age patients. Studies not measuring troughs or defining a different cut-off point than 15 mg/L were excluded. Data on age, exclusion criteria, nephrotoxicity definition, risk factors for nephrotoxicity and vancomycin trough levels were extracted from selected papers.

RESULTS

Ten studies were identified for meta-analysis. All subjects had comparatively normal baseline serum creatinine values. Common risk factors identified included elevated (≥15 mg/L) trough levels, renal impairment, hypovolemia and concurrent use of nephrotoxic medications. Troughs ≥15 mg/L increased nephrotoxicity by 2.7-fold (odds ratio (OR), 2.71; 95% confidence interval: 1.82-4.05; I(2) = 40%; Q = 0.09). These odds were further increased among patients in the pediatric intensive care unit (OR, 3.61; 95% confidence interval: 1.21-10.74; I(2) = 45%; Q = 0.18).

CONCLUSIONS

Though the rate of vancomycin-induced nephrotoxicity is increased in pediatric patients with higher vancomycin troughs, other factors such as intensive care unit admission, hypovolemia and concurrent nephrotoxic drug use appear to contribute to the development of nephrotoxicity.

Antimicrobial Stewardship in Long-Term Care Facilities: Approaches to Creating an Antibiogram when Few Bacterial Isolates Are Cultured Annually

Antibiograms are important clinical tools to report and track antibiotic susceptibility and help guide empiric antimicrobial therapy. Antibiograms support compliance with antimicrobial stewardship (AMS) requirements from the Centers for Medicare and Medicaid Services and are in line with recommendations from the Centers for Disease Control and Prevention Core Elements of AMS for nursing homes/long-term care facilities (LTCFs). Unlike most acute-care settings, LTCFs are challenged in creating antibiograms because of the low number of bacterial isolates collected annually. Determining the best methodology for creating clinically useful antibiograms for LTCFs needs to be explored. Possible approaches include (1) extending the isolate data beyond 1 year, (2) combining isolate data from the same geographic region, (3) using a nearby acute-care facility's antibiogram as a proxy, or (4) collapsing isolate data. This article discusses the benefits and limitations of each approach.

Facilitators and Barriers to Antibiotic Stewardship: A Qualitative Study of Pharmacists' Perspectives

Background: The Veterans Affairs (VA) is a leader in the implementation and advancement of antibiotic stewardship programs throughout the nation. The Centers for Disease Control and Prevention (CDC) has also led national antibiotic stewardship efforts and has outlined core elements to improve antibiotic use in hospitals, long-term care, and outpatient settings. Many facilities still face challenges to the implementation and maintenance of successful programs, particularly in nonacute care settings. The objective of this study was to identify barriers and facilitators to antibiotic stewardship within the VA medical centers through qualitative interviews with pharmacists. Methods: Eight semi-structured telephone interviews were conducted with pharmacists from 6 VA medical centers within VA New England Healthcare System. Pharmacist respondents were either pharmacy champions (for medical centers with established programs) or pharmacists with responsibilities in making antibiotic recommendations (locations without established programs). All interviews were audio recorded and transcribed verbatim. NVivo 8 was used for data coding and analysis. Results: Pharmacists from all 8 medical centers were contacted for interviews and pharmacists from 6 medical centers agreed to interviews (75% VA New England medical center participation). Three main themes regarding antibiotic stewardship were identified from the interviews with pharmacists. Respondents described the importance of (1) a supportive organizational culture, (2) protected time for antibiotic stewardship, and (3) a cohesive organizational structure in the success of antibiotic stewardship programs. Conclusions: Our findings support the CDC core elements for antibiotic stewardship, in particular the importance of leadership commitment in the creation of a culture that supports antibiotic stewardship and in ensuring staff are given sufficient time for antibiotic stewardship efforts. Although a strong supportive culture has been built, strategies focused on fostering increased protected time for antibiotic stewardship and a cohesive organizational structure may be helpful in advancing and sustaining successful antibiotic stewardship programs that improve patient outcomes.

Communicating with Facility Leadership; Metrics for Successful Antimicrobial Stewardship Programs (Asp) in Acute Care and Long-Term Care Facilities

Up to 50% of hospital-administered and 70% of nursing home-administered antimicrobials are inappropriately prescribed. There is a great need to focus local, national and global efforts on appropriate antibiotic use. Formal programs dedicated to appropriate antibiotic use have been established in most US hospitals. These antimicrobial stewardship programs (ASP) exist to ensure that the correct drug, dose and duration of an antimicrobial is given, and only when there is a true bacterial infection (as opposed to bacterial colonization or a viral infection). These programs increase patient safety and reduce unintended consequences including Clostridium difficile infections, medication-related adverse effects, and antimicrobial resistance. Most of these programs are co-lead by an interdisciplinary team consisting of an infectious diseases (ID) pharmacist and an ID physician. However, consistent and meaningful metrics to study the impact of ASPs have not been elucidated. With the Joint Commission Standards for Acute Care facilities, and Centers for Medicare and Medicare (CMS) for long-term care facilities making antimicrobial stewardship (AMS) a condition of participation, both facilities will be scrambling to create appropriate quality care indicators to measure program success. One major theme across all healthcare settings is that ASPs must collaborate with facility leadership and key stakeholders at each institution in order to have an impactful benefit on patient quality of care, and safety. It is the purpose of this review to offer several economic, process, and patient-outcome measurements for ASP to optimally communicate with facility leadership.

Association of Higher Daptomycin Dose (7 mg/kg or Greater) with Improved Survival in Patients with Methicillin-Resistant Staphylococcus aureus Bacteremia

STUDY OBJECTIVE

Current guidelines recommend higher daptomycin doses than the daptomycin label dose of 6 mg/kg for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia; however, the evidence supporting this recommendation is from in vitro and case series studies. This study evaluated the comparative effectiveness of the daptomycin label dose versus higher daptomycin doses in patients with MRSA bacteremia.

DESIGN

Retrospective national cohort study.

SETTING

Veterans Affairs medical centers.

PATIENTS

A total of 371 adults with MRSA bacteremia who were admitted between 2002 and 2015 and treated initially with vancomycin within 24 hours of initial culture collection and then switched to daptomycin therapy within 7 days; 138 patients (37.2%) received daptomycin doses higher than the daptomycin label dose (7 mg/kg or greater), and 233 (62.8%) received the daptomycin label dose (6 mg/kg).

MEASUREMENTS AND MAIN RESULTS

Clinical outcomes were compared among those who received the daptomycin label dose and those who received the higher dose using propensity score-matched Cox proportional hazards regression models. To identify dose partitioning associated with optimal survival, classification and regression tree (CART) analysis was used among patients, controlling for confounding with a 30-day mortality disease risk score. Propensity score-matched 30-day mortality was 8.6% (6/70 patients) among the higher dose group versus 18.6% (13/70 patients) among the label dose group (hazard ratio 0.31, 95% confidence interval 0.10-0.94). No significant differences were observed in inpatient mortality, length of stay, 30-day readmission, or 30-day S. aureus reinfection between groups. CART analysis resulted in doses of 7 mg/kg or greater providing benefit only among patients with higher (more than 51%) predicted probabilities of 30-day mortality (p<0.001).

CONCLUSION

To our knowledge, this is the first comparative effectiveness study of daptomycin doses in patients with MRSA bacteremia. Survival benefits were observed with doses higher than the daptomycin label dose (7 mg/kg or greater) for the treatment of MRSA bacteremia. These data suggest that higher doses than the daptomycin label dose may be preferred over the label dose for improving clinical outcomes in patients with MRSA bacteremia.