Clinical outcomes in patients with piperacillin/ tazobactam-non-susceptible but ceftriaxone-susceptible E. coli or K. pneumoniae bloodstream infection

BACKGROUND

A small proportion of Escherichia coli and Klebsiella pneumoniae demonstrate in vitro non-susceptibility to piperacillin/tazobactam but retain susceptibility to ceftriaxone. Uncertainty remains regarding how best to treat these isolates.

OBJECTIVES

We sought to compare clinical outcomes between patients with piperacillin/tazobactam-non-susceptible but ceftriaxone-susceptible E. coli or K. pneumoniae bloodstream infection receiving definitive therapy with ceftriaxone versus an alternative effective antibiotic.

METHODS

We retrospectively identified patients with a positive blood culture for piperacillin/tazobactam-non-susceptible but ceftriaxone-susceptible E. coli or K. pneumoniae between 1 January 2013 and 31 December 2022. Patients were divided into one of two definitive treatment groups: ceftriaxone or alternative effective antibiotic. Our primary outcome was a composite of 90 day all-cause mortality, hospital readmission, or recurrence of infection. We used Cox proportional hazards models to compare time with the composite outcome between groups.

RESULTS

Sixty-two patients were included in our analysis. Overall, median age was 63 years (IQR 49.5-71.0), the most common source of infection was intra-abdominal (25/62; 40.3%) and the median total duration of therapy was 12.0 days (IQR 9.0-16.8). A total of 9/22 (40.9%) patients in the ceftriaxone treatment group and 18/40 (45.0%) patients in the alternative effective antibiotic group met the composite endpoint. In an adjusted time-to-event analysis, there was no difference in the composite endpoint between groups (HR 0.67, 95% CI 0.30-1.50). The adjusted Bayesian posterior probability that the HR was less than or equal to 1 (i.e. ceftriaxone is as good or better than alternative therapy) was 85%.

CONCLUSIONS

These findings suggest that ceftriaxone can be used to effectively treat bloodstream infections with E. coli or K. pneumoniae that are non-susceptible to piperacillin/tazobactam but susceptible to ceftriaxone.

Antimicrobial stewardship knowledge, attitudes, and practices (KAP) among nurses

We performed a knowledge, attitudes, and practice (KAP) survey of bedside nurses to evaluate perceptions of antimicrobial use and aid in the design of nursing-based antimicrobial stewardship interventions. The survey highlighted discrepancies in knowledge and practice as well as opportunities to improve communication with nursing colleagues.

Teams in Transition: Increasing Role of Advanced Practice Providers in Antimicrobial Use and Infectious Diseases Consultation

Background

Advanced practice providers (APPs) have taken on increasing responsibilities as primary team members in acute care hospitals, but the impact of this practice shift on antimicrobial prescribing and infectious diseases (ID) consultation requests is unknown. Here we describe longitudinal trends in antimicrobial days of therapy (DOT) and ID consultation by attributed provider type in 3 hospitals.

Methods

We performed a retrospective time series analysis of antimicrobial use and ID consultation from July 2015 to June 2022 at a major university hospital and 2 community hospitals. We evaluated antimicrobial DOT and ID consultation over time and assessed attribution to 3 groups of providers: attending physicians, trainees, and APPs. We used multinomial logistic regression to measure changes in percentage of DOT and ID consultation across the clinician groups over time using physicians as the referent.

Results

Baseline distribution of antimicrobial DOT and ID consultation varied by practice setting, but all subgroups showed increases in the proportion attributable to APPs. Large increases were seen in the rate of ID consultation, increasing by >30% during the study period. At our university hospital, by study end >40% of new ID consults and restricted antimicrobial days were attributed to APPs.

Conclusions

Hospitals had differing baseline patterns of DOT attributed to provider groups, but all experienced increases in DOT attributed to APPs. Similar increases were seen in changes to ID consultation. APPs have increasing involvement in antimicrobial use decisions in the inpatient setting and should be engaged in future antimicrobial stewardship initiatives.

Penicillin Allergy Impact and Management

There is international evidence that penicillin allergies are associated with inferior prescribing and patient outcomes. A host of tools now exist from assessment (risk assessment tools, clinical decision rules) to delabeling (the removal of a beta-lactam allergy via testing or medical reconciliation) to reduce the impact of these "labels" in the hospital and community setting, as a primary antimicrobial stewardship intervention.

Comparison of Open-Access, Trough-Only Online Calculators Versus Trapezoidal Method for Calculation of Vancomycin Area Under the Curve (AUC)

BACKGROUND

Vancomycin area-under-the-curve (AUC) monitoring is associated with reduced nephrotoxicity but may increase cost and workload for personnel compared to trough monitoring.

OBJECTIVE

The purpose of this study was to compare the accuracy of vancomycin AUC calculated by open-access, online, trough-only calculators to AUCs calculated by the trapezoidal method (TM) using peak and trough concentrations.

METHODS

This retrospective, multi-center study included adults ≥18 years old with stable renal function who received vancomycin with steady-state peak and trough concentrations. Areas under the curve calculated by TM were compared to AUCs calculated by 3 online calculators using trough-only options for calculation: ClinCalc, VancoVanco, and VancoPK. The primary outcome was actual difference in AUC between TM and the online calculators. Secondary outcomes were percent difference in AUC and clinical alignment in dose adjustments between methods.

RESULTS

Seventy patients were included for analysis. There was a statistically significant difference in AUC between TM and ClinCalc (median actual difference: -52, P < 0.001) and VancoVanco (median actual difference: 95, P < 0.001), whereas there was no significant difference between TM and VancoPK (median actual difference: -0.8, P = 0.827). Discordant dose adjustments were indicated when comparing ClinCalc, VancoVanco, and VancoPK to TM in 28%, 36%, and 12% of cases, respectively.

CONCLUSION

The AUC calculator most closely aligned with TM was VancoPK, whereas other included calculators were statistically different. Owing to the cost and complexity of obtaining multiple levels, our findings support using a single steady-state trough using VancoPK as an alternative to TM for calculation of vancomycin AUC.

Evaluation of an Opt-Out Protocol for Antibiotic De-Escalation in Patients With Suspected Sepsis: A Multicenter, Randomized, Controlled Trial

BACKGROUND

Sepsis guidelines recommend daily review to de-escalate or stop antibiotics in appropriate patients. This randomized, controlled trial evaluated an opt-out protocol to decrease unnecessary antibiotics in patients with suspected sepsis.

METHODS

We evaluated non-intensive care adults on broad-spectrum antibiotics despite negative blood cultures at 10 US hospitals from September 2018 through May 2020. A 23-item safety check excluded patients with ongoing signs of systemic infection, concerning or inadequate microbiologic data, or high-risk conditions. Eligible patients were randomized to the opt-out protocol vs usual care. Primary outcome was post-enrollment antibacterial days of therapy (DOT). Clinicians caring for intervention patients were contacted to encourage antibiotic discontinuation using opt-out language. If continued, clinicians discussed the rationale for continuing antibiotics and de-escalation plans. To evaluate those with zero post-enrollment DOT, hurdle models provided 2 measures: odds ratio of antibiotic continuation and ratio of mean DOT among those who continued antibiotics.

RESULTS

Among 9606 patients screened, 767 (8%) were enrolled. Intervention patients had 32% lower odds of antibiotic continuation (79% vs 84%; odds ratio, 0.68; 95% confidence interval [CI], .47-.98). DOT among those who continued antibiotics were similar (ratio of means, 1.06; 95% CI, .88-1.26). Fewer intervention patients were exposed to extended-spectrum antibiotics (36% vs 44%). Common reasons for continuing antibiotics were treatment of localized infection (76%) and belief that stopping antibiotics was unsafe (31%). Thirty-day safety events were similar.

CONCLUSIONS

An antibiotic opt-out protocol that targeted patients with suspected sepsis resulted in more antibiotic discontinuations, similar DOT when antibiotics were continued, and no evidence of harm.

CLINICAL TRIALS REGISTRATION

NCT03517007.

Optimizing reflex urine cultures: Using a population-specific approach to diagnostic stewardship

BACKGROUND

Clinicians and laboratories routinely use urinalysis (UA) parameters to determine whether antimicrobial treatment and/or urine cultures are needed. Yet the performance of individual UA parameters and common thresholds for action are not well defined and may vary across different patient populations.

METHODS

In this retrospective cohort study, we included all encounters with UAs ordered 24 hours prior to a urine culture between 2015 and 2020 at 3 North Carolina hospitals. We evaluated the performance of relevant UA parameters as potential outcome predictors, including sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV). We also combined 18 different UA criteria and used receiver operating curves to identify the 5 best-performing models for predicting significant bacteriuria (≥100,000 colony-forming units of bacteria/mL).

RESULTS

In 221,933 encounters during the 6-year study period, no single UA parameter had both high sensitivity and high specificity in predicting bacteriuria. Absence of leukocyte esterase and pyuria had a high NPV for significant bacteriuria. Combined UA parameters did not perform better than pyuria alone with regard to NPV. The high NPV ≥0.90 of pyuria was maintained among most patient subgroups except females aged ≥65 years and patients with indwelling catheters.

CONCLUSION

When used as a part of a diagnostic workup, UA parameters should be leveraged for their NPV instead of sensitivity. Because many laboratories and hospitals use reflex urine culture algorithms, their workflow should include clinical decision support and or education to target symptomatic patients and focus on populations where absence of pyuria has high NPV.

Impact of COVID ‐19 pandemic on pharmacist‐led allergy assessments and penicillin skin testing

Allergy assessments and penicillin skin testing are associated with reductions in high‐Clostridioides difficile infection (CDI)‐risk antibiotic use and lower hospital‐acquired CDI rates; however, these activities require substantial personnel and resource allocation. Recently, many antimicrobial stewardship programs’ (ASPs) focus shifted towards supporting the COVID‐19 pandemic response. We evaluated the impact of the COVID‐19 pandemic on a pharmacist‐led allergy assessment and penicillin skin testing program. Patients undergoing allergy assessment and/or penicillin skin testing (PST) from 1 January 2017 through 30 April 2021 were included for review. Monthly PST and allergy assessment rates were calculated and defined as the number of PSTs or allergy assessments per 1000 unique patient encounters for each month, respectively. The study used interrupted time series regression to assess potential level and slope changes in allergy assessments and PSTs during the pandemic. 200 058 total inpatient encounters by 188 867 unique patients occurred during the study period. ASP performed 918 allergy assessments and 204 PSTs. The local onset of the SARS‐CoV‐2 pandemic during March 2020 was associated with significant level reductions in allergy assessments and PSTs. Additional responsibilities added to the ASP team during the COVID‐19 pandemic limited the ability to perform core antimicrobial stewardship activities with proven patient care benefits.

Impact of Education and Data Feedback on Guideline-Concordant Prescribing for Urinary Tract Infections in the Outpatient Setting

Background

Urinary tract infections (UTIs) are the most common outpatient indication for antibiotics and an important target for antimicrobial stewardship (AS) activities. With The Joint Commission standards now requiring outpatient AS, data supporting effective strategies are needed.

Methods

We conducted a 2-phase, prospective, quasi-experimental study to estimate the effect of an outpatient AS intervention on guideline-concordant antibiotic prescribing in a primary care (PC) clinic and an urgent care (UC) clinic between August 2017 and July 2019. Phase 1 of the intervention included the development of clinic-specific antibiograms and UTI diagnosis and treatment guidelines, presented during educational sessions with clinic providers. Phase 2, consisting of routine clinic- and provider-specific feedback, began ~12 months after the initial education. The primary outcome was percentage of encounters with first- or second-line antibiotics prescribed according to clinic-specific guidelines and was assessed using an interrupted time series approach.

Results

Data were collected on 4724 distinct patients seen during 6318 UTI encounters. The percentage of guideline-concordant prescribing increased by 22% (95% CI, 12% to 32%) after Phase 1 education, but decreased by 0.5% every 2 weeks afterwards (95% CI, –0.9% to 0%). Following routine data feedback in Phase 2, guideline concordance stabilized, and significant further decline was not seen (–0.6%; 95% CI, –1.6% to 0.4%). This shift in prescribing patterns resulted in a 52% decrease in fluoroquinolone use.

Conclusions

Clinicians increased guideline-concordant prescribing, reduced UTI diagnoses, and limited use of high-collateral damage agents following this outpatient AS intervention. Routine data feedback was effective to maintain the response to the initial education.

Impact of Education and Data Feedback on Antibiotic Prescribing for Urinary Tract Infections in the Emergency Department: An Interrupted Time Series Analysis

BACKGROUND

Urinary tract infections (UTIs) are often misdiagnosed or treated with exceedingly broad-spectrum antibiotics, leading to negative downstream effects. We aimed to implement antimicrobial stewardship (AS) strategies targeting UTI prescribing in the emergency department (ED).

METHODS

We conducted a quasi-experimental prospective AS intervention outlining appropriate UTI diagnosis and management across three EDs, within an academic and two community hospitals, in North Carolina, United States. The study was divided into three phases, a baseline period and two intervention phases. Phase 1 included introduction of an ED-specific urine antibiogram and UTI guideline, education, and department-specific feedback on UTI diagnosis and antibiotic prescribing. Phase 2 included re-education and provider-specific feedback. Eligible patients included adults with an antibiotic prescription for UTI diagnosed in the ED from 11/13/18 to 3/1/21. Admitted patients were excluded. The primary outcome was guideline-concordant antibiotic use, assessed using an interrupted time series regression analysis with 2-week intervals.

RESULTS

Overall, 8,742 distinct patients with 10,426 patient encounters were included. Ninety-two percent of all encounters (n=9,583) were diagnosed with cystitis and 8.1% with pyelonephritis (n=843). There was an initial 15% increase in guideline-concordant antibiotic prescribing in Phase 1 compared to the pre-intervention period (incidence rate ratio [IRR] 1.15; 95% confidence interval [CI] 1.03 to 1.29). A significant increase of guideline-concordant prescriptions was seen with every two-week interval during Phase 2 (IRR 1.03; 95% CI 1.01 to 1.04).

CONCLUSIONS

This multifaceted AS intervention involving a guideline, education, and provider-specific feedback increased guideline-concordant antibiotic choices for treat-and-release patients in the ED.

Impact of Antibiotic Stewardship Rounds in the Intensive Care Setting: a prospective cluster-randomized crossover study

BACKGROUND

Few groups have formally studied the effect of dedicated antibiotic stewardship rounds (ASRs) on antibiotic use (AU) in intensive care units (ICUs).

METHODS

We implemented weekly ASRs using a two-arm, cluster-randomized, crossover study in 5 ICUs at Duke University Hospital from 11/2017 to 6/2018. We excluded patients without an active antibiotic order, or if they had a marker of high complexity including an existing infectious disease consult, transplant, ventricular assist device, or ECMO. AU during and following ICU stay for patients with ASRs was compared to the controls. We recorded the number of reviews, recommendations delivered, and responses. We evaluated change in ICU-specific AU during and after the study.

RESULTS

Our analysis included 4,683 patients: 2330 intervention and 2353 controls. Teams performed 761 reviews during ASRs, which excluded 1569 patients: 60% of patients off antibiotics, and 8% complex patients. Exclusions affected 88% the cardiac surgery ICU (CTICU) patients. AU rate ratio (RR) was 0.97 (0.91-1.04). When CTICU was removed, the RR was 0.93 (0.89-0.98). AU in the post-study period decreased by 16% (95% CI 11-24%) compared to the AU in the baseline period. Change in AU was differential among units: largest in the neurology ICU (-28%) and smallest in the CTICU (-2%).

CONCLUSION

Weekly multi-disciplinary ASRs was a high-resource intervention associated with a small AU reduction. The noticeable ICU AU decline over time is possibly due to indirect effects of ASRs. Effects differed among specialty ICUs, emphasizing the importance of customizing ASRs to match unit-specific population, workflow, and culture.

Antimicrobial Stewardship Practice in the Ambulatory Setting From a National Cohort

Background

The majority of antimicrobial use occurs in the ambulatory setting. Antimicrobial stewardship programs (ASPs) are effective in improving appropriate prescribing and are now required by accreditation bodies.

Methods

This was a cross-sectional, multicenter survey describing the current state of ambulatory ASPs in a national cohort of Vizient member hospitals with ambulatory healthcare settings and serves as a benchmark for stewardship strategies related to program effectiveness.

Results

One hundred twenty-nine survey responses from a variety of institution types across 44 states were received. Survey respondents reported a fully functioning ASP in 7% (9 of 129) of ambulatory practices compared with 88% (114 of 129) of inpatient institutions. Effectiveness in at least 1 antibiotic use-related outcome (ie, utilization, resistance, Clostridioides difficile infection, or cost) in the past 2 years was reported in 18% (18 of 100) of ambulatory and 84% (103 of 123) of inpatient ASPs. Characteristics of ambulatory ASPs demonstrating effectiveness were institution guidelines (89%, 16 of 18), rapid diagnostic testing for respiratory viruses or group A Streptococcus (89% 16 of 18), outpatient antibiograms (78% 14 of 18), and dedicated pharmacist support (72%, 13 of 18). Ambulatory ASP effectiveness was shown to increase as programs met more of the Centers for Disease Control and Prevention (CDC) Core Elements of Outpatient Antimicrobial Stewardship (P < .001).

Conclusions

Antimicrobial stewardship programs are needed in the ambulatory setting, but they are not common. Currently, few ambulatory ASPs in this survey self-identify as fully functioning. The CDC Core Elements of antimicrobial stewardship should remain foundational for ASP development and expansion.

Influence of Reported Penicillin Allergy on Mortality in MSSA Bacteremia

Background

Penicillin allergy frequently impacts antibiotic choice. As beta-lactams are superior to vancomycin in treating methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia, we examined the effect of reported penicillin allergy on clinical outcomes in patients with MSSA bacteremia.

Methods

In this retrospective cohort study of adults with MSSA bacteremia admitted to a large tertiary care hospital, outcomes were examined according to reported penicillin allergy. Primary outcomes included 30-day and 90-day mortality rates. Multivariable regression models were developed to quantify the effect of reported penicillin allergy on mortality while adjusting for potential confounders.

Results

From 2010 to 2015, 318 patients with MSSA bacteremia were identified. Reported penicillin allergy had no significant effect on adjusted 30-day mortality (odds ratio [OR], 0.73; 95% confidence interval [CI], 0.29-1.84; P = .51). Patients with reported penicillin allergy were more likely to receive vancomycin (38% vs 11%, P < .01), but a large number received cefazolin regardless of reported allergy (29 of 66, 44%). Mortality rates were highest among nonallergic patients receiving vancomycin (22.6% vs 7.4% for those receiving beta-lactams regardless of reported allergy, P < .01). In multivariable analysis, beta-lactam receipt was most strongly associated with survival (OR, 0.26; 95% CI, 0.12-0.54).

Conclusions

Reported penicillin allergy had no significant effect on 30- or 90-day mortality. Non-penicillin-allergic patients receiving vancomycin for treatment of MSSA bacteremia had the highest mortality rates overall. Receipt of a beta-lactam was the strongest predictor of survival. These results underscore the importance of correct classification of patients with penicillin allergy and appropriate treatment with a beta-lactam when tolerated.

Extended infusion compared to standard infusion cefepime as empiric treatment of febrile neutropenia

Background Extended infusion (EI) dosing provides a longer time above the minimum inhibitory concentration, which is important for the clinical success of β-lactam antibiotics, especially for patients with impaired immunity. The aim of this study was to determine the feasibility and clinical impact of administering cefepime by EI as treatment of febrile neutropenia. Methods This was a prospective, randomized, comparative pilot study. All patients received cefepime 2 g IV every 8 h, with the first dose administered using a 30-min infusion. After the first dose, patients were randomized to receive cefepime over 30 min as a standard infusion (SI) or 3 h (EI). Patients were >18 years old with febrile neutropenia (neutrophil count <500 cells/mm³ and temperature >38.0ºC) and received chemotherapy or stem cell transplant as treatment for malignancy. Patients were excluded for the following: allergy to a cephalosporin, creatinine clearance (CrCl) < 50 mL/min, receipt of concurrent Gram-negative antimicrobial, sepsis, or solid tumor malignancy. The primary outcome was defervescence by 72 h. Secondary outcomes included time to defervescence, clinical success, in-hospital mortality, hospital length of stay, and need for additional antimicrobials. Main results Sixty-three patients were enrolled: 33 in the SI arm and 30 in the EI arm. The groups were similar with regard to age, gender, weight, estimated creatinine clearance, and duration of neutropenia. None of the patients in the EI arm withdrew due to practical complications of receiving EI cefepime. Twenty-three patients in the SI arm and 20 patients in the EI arm defervesced by 72 h ( p = 0.99). There were no differences in secondary outcome measures; however, patients in the EI arm appeared to have defervesced more rapidly (median 19 vs. 41 h, p = 0.305). Conclusion Administration of cefepime by EI for the treatment of febrile neutropenia is feasible. Larger clinical trials are necessary to determine if EI cefepime imparts a clinical benefit in the treatment of febrile neutropenia.

Zidovudine as modern day salvage therapy for HIV infection

Resistance to the first-line NRTIs, tenofovir and emtricitabine, does not generally confer resistance to zidovudine. The objective of this study was to describe the efficacy of zidovudine as modern day salvage antiretroviral therapy. This was a single-center, retrospective, observational, cohort study. Adult HIV-positive patients prescribed a zidovudine-containing regimen between 2005 and 2010 were identified from a computer database. All patients had failed at least one prior antiretroviral regimen before zidovudine. The primary outcome measure was virologic success at 24 weeks. Other efficacy and safety outcomes were determined, including virologic success at 48 and 96 weeks, CD4 count change from baseline, and incidence of adverse effects. Sixty-nine subjects were enrolled. The mean age was 43 years, 70% were male, and 85.5% were black. Most patients were highly antiretroviral experienced. At 24 weeks, 63.8% and 72.5% of patients achieved HIV RNA less than 50 and 400 c/mL, respectively. The median change in CD4 count from baseline to week 24 was +70 cells/mm(3). The percent of patients who discontinued zidovudine due to adverse effects was 10%. In this highly treatment-experienced population, zidovudine as part of a salvage regimen appeared effective. Gastrointestinal adverse effects were reported, but zidovudine-associated metabolic effects were uncommon, suggesting zidovudine was generally well tolerated.

Show me the money: long-term financial impact of an antimicrobial stewardship program

The financial impact of an antimicrobial stewardship program in operation for more than 11 years was determined by calculating the reduction in antimicrobial expenditures minus program labor costs. Depending on the method of inflation adjustment used, the program was associated with average cost savings of $920,070 to $2,064,441 per year.