Impact of Penicillin Allergy on Empirical Carbapenem Use in Gram-Negative Bloodstream Infections: An Antimicrobial Stewardship Opportunity

Self-Reported Penicillin Allergy and antibiotic use in critical care: An observational, retrospective study

BACKGROUND

Patients with Self-Reported Penicillin Allergy (SRPA) receive alternative antibiotics, which increase the length of stay and hospital costs, but the impact of SRPA on mortality in critically ill patients is not well described.

METHODS

This was a single-center, retrospective analysis of routinely gathered clinical data for all intensive care unit (ICU) admissions over nine years. The primary outcome was 28-day mortality, which was analyzed using a time-to-event approach with multivariable models to adjust for confounding factors, including age, comorbidities, sex, and admission SOFA score (as a measure of organ dysfunction). Antibiotic prescriptions during the ICU stay were also interrogated and compared.

RESULTS

Of 35,319 admissions, 11.7% had SRPA. Compared with non-SRPA, patients with SRPA were more likely to be female (52.2% vs. 37.4%, p < 0.001) and had more comorbidities (p < 0.001) but had similar admission SOFA scores (median: 3.5 in both groups, p = 0.839). Patients with SRPA had significantly lower 28-day mortality (9.6% vs. 10.9%, p = 0.011). After multivariable adjustment for baseline characteristics, this effect persisted for unplanned (hazard ratio [HR]: 0.76, 95% CI: 0.68-0.86, p < 0.001), but not planned admissions (HR: 1.21, 95% CI: 0.92-1.58, p = 0.172). Whilst the duration of antibiotics in ICU was similar in the SRPA and non-SRPA groups (mean: 3.4 vs. 3.4 days, p = 0.663), the antibiotics used differed, with SRPA patients being significantly more likely to receive quinolones or other anti-Gram-positive antibiotics (p < 0.001).

CONCLUSION

SRPA was associated with a survival benefit that persisted after adjustment for confounders for unplanned ICU admissions. Patients with SRPA were more likely to receive antibiotics that are not active against anaerobic bacteria.

Assessing the rationale of prescribing carbapenems among hospitalized patients with documented penicillin allergy: implications for stewardship

Background

A reported history of penicillin allergy frequently leads to the prescription of carbapenems as a substitute for penicillin to avoid allergic reactions. Such self-reported allergies need to be accurately characterized to identify targeted antibiotic stewardship interventions that potentially minimize unnecessary carbapenem use.

Design

Retrospective cohort study.

Method

The proportion of hospitalized patients with penicillin allergy history receiving carbapenem prescriptions was evaluated between January 1st, 2017 and December 31st, 2018 at the University Hospital Basel, Switzerland. The appropriateness of carbapenem prescription of each patient was evaluated using institutional guidelines based on previously published recommendations.

Results

Our analysis revealed that among 212 patients with recorded penicillin allergy, of the 247 carbapenem treatment episodes, 79 (32%) were unjustified. Abdominal and lower respiratory tract infections were most frequently associated with inappropriate carbapenem use (OR 2.64, 95% CI 1.22-5.71, P = .014 and OR 2.26, 95% CI 1.08-4.73, P = .031). The recorded allergy type was not documented or unclear in 153 patients (72%) and penicillin allergy was only confirmed in 2 patients (0.9%). Inconsistencies in allergic symptom documentation and allergy types were found between the institution's two software programs.

Conclusion

While a multimodal approach to identify and accurately label penicillin allergies remains essential to reduce inappropriate carbapenem use, our findings highlight the need for comprehensive and easily accessible guidelines for carbapenem utilization and structured history-based allergy assessment as an initial screening tool, embedded in a tailored digital allergy record template.

Instruction and Simulation to Improve Pharmacy Students' Knowledge and Confidence Regarding Assessment of Penicillin Allergies

Objective. To evaluate pharmacy students' knowledge of and confidence regarding penicillin allergy assessment and skin testing (PAAST) before and after a focused didactic instruction and simulation (FDIS).Methods. A multicenter, quasi-experimental, cross-sectional survey study was performed among pharmacy students before and after FDIS on PAAST at two schools of pharmacy. The FDIS on PAAST consisted of an infectious disease faculty-led seminar, student-led penicillin allergy counseling interviews, penicillin skin testing simulation, and case studies to assess penicillin allergy scenarios and management. An anonymous, voluntary, electronic survey was distributed to students (n=159) before and after the FDIS. The pre- and post-intervention survey contained 10 PAAST knowledge-based questions and multi-step, five-point Likert scale statements related to students' confidence in PAAST. The post-intervention survey also evaluated students' perceptions of the FDIS on PAAST. Descriptive statistics were performed, and the Student t test was used to compare pre- and post-intervention responses.Results. One hundred forty-three surveys were completed, resulting in a survey response rate of 90%. Students' PAAST knowledge scores (mean±SD) increased overall following the FDIS on PAAST (6.67±1.51 vs 7.81±1.39). Knowledge scores increased considerably for questions related to penicillin allergy consequences, cross-reactivity, and correct steps of PAAST. Pharmacy students' PAAST confidence scores (mean±SD) also improved following the interactive instruction and simulation (2.30±0.7 vs 3.22±0.67) with considerable confidence increases in penicillin skin testing. Pharmacy students' perceptions of the FDIS on PAAST were also positive overall.Conclusion. Pharmacy students' knowledge and confidence of PAAST improved following FDIS. This may be an effective strategy to implement PAAST education during pharmacy school.

A comprehensive assessment of carbapenem use across 90 Veterans Health Administration hospitals with defined stewardship strategies for carbapenems

OBJECTIVES

Carbapenems are an important target for antimicrobial stewardship (AS) efforts. In this study, we sought to compare different hospital-based strategies for improving carbapenem use.

METHODS

We analysed a cohort of all patients hospitalized at Veterans Health Administration (VHA) acute care hospitals during 2016 and a mandatory survey that characterized each hospital's carbapenem-specific AS strategy into one of three types: no strategy (NS), prospective audit and feedback (PAF) or restrictive policies (RP). Carbapenem use was compared using risk-adjusted generalized estimating equations that accounted for clustering within hospitals. Two infectious disease (ID) physicians independently performed manual chart reviews in 425 randomly selected cases. Auditors assessed carbapenem appropriateness with an assessment score on Day 4 of therapy.

RESULTS

There were 429 062 admissions in 90 sites (24 NS, 8 PAF, 58 RP). Carbapenem use was lower at PAF than NS sites [rate ratio (RR) 0.6 (95% CI 0.4-0.9); P = 0.01] but similar between RP and NS sites. Carbapenem prescribing was considered appropriate/acceptable in 215 (50.6%) of the reviewed cases. Assessment scores were lower (i.e. better) at RP than NS sites (mean 2.3 versus 2.7; P < 0.01) but did not differ significantly between NS and PAF sites. ID consultations were more common at PAF/RP than NS sites (51% versus 29%; P < 0.01). ID consultations were associated with lower (i.e. better) assessment scores (mean 2.3 versus 2.6; P < 0.01).

CONCLUSIONS

In this VHA cohort, PAF strategies were associated with lower carbapenem use and ID consultation and RP strategies were associated with more appropriate carbapenem prescribing. AS and ID consultations may work complementarily and hospitals could leverage both to optimize carbapenem use.

Skin Testing for Penicillin Allergy: a Review of the Literature

PURPOSE OF REVIEW

Self-reported penicillin allergies are frequently reported, though more than 95% of those are not truly allergic when challenged. These patients are more likely to receive alternative antibiotic regimens resulting in the use of broad-spectrum antibiotics that may be less effective, more toxic, and/or more expensive than preferred agents. Given the significant burden on patient outcomes and the healthcare system, the ability to reconcile an allergy and broaden future antibiotic options is essential.

RECENT FINDINGS

This is a narrative review describing risk stratification for penicillin skin testing, practical advice for implementation, and future directions. A summary of studies within the last 5 years is provided. The trend over the past several years has been to offer oral drug challenges to low-risk patients and skin testing to high-risk patients with a reported penicillin allergy. This review provides support for risk stratification assessment of reported penicillin allergy to optimize antibiotic use and prevent emergence of antimicrobial resistance.

The role of a clinical pharmacist in spurious Penicillin allergy: a narrative review

Background A label of penicillin allergy is held by 6-10% of the general population and 15-20% of inpatients. > 90% of these labels are found to be spurious after formal allergy assessment. Carrying an unnecessary label of penicillin allergy is not benign. Such patients may receive second line, more expensive antibiotics, representing a significant impediment to antimicrobial stewardship. Aim of the review To (a) Explain the burden of spurious penicillin allergy, and evaluate the safety of direct oral penicillin challenge in 'low risk' patients (b) appraise the place for a clinical pharmacist-led penicillin allergy de-labelling programme. Method Narrative review. Search engines: PubMed, Google Scholar and Cochrane reviews. Search criteria: English language; search terms: penicillin allergy, antimicrobial stewardship, antimicrobial resistance, clostridium difficile, vancomycin resistant enterococci, risk stratification, clinical pharmacist and direct oral provocation test Results Penicillin allergy labels are associated with: longer hospital stay, higher readmission rates, enhanced risk of surgical site infections, risk of Clostridioides difficile infection and Methicillin resistant Staphylococcus aureus infection, a delay in the first dose of an antibiotic in sepsis and higher healthcare costs. A direct oral penicillin challenge in 'low risk' patients has proven to be safe. Discussion Recent studies including those led by a clinical pharmacist have demonstrated safety of a direct oral penicillin challenge in 'low risk' patients. This intervention needs validation within individual health services. Conclusion Direct oral penicillin challenge reduces the adverse impact of spurious penicillin allergy. A pharmacist-led penicillin allergy de-labelling program needs further validation in prospective multi-centre studies.

Syndrome-specific versus prospective audit and feedback interventions for reducing use of broad-spectrum antimicrobial agents

BACKGROUND

Antimicrobial use (AU) of antipseudomonal β-lactams (APBL) has significantly increased over the past decade in US hospitals. This retrospective cohort study compares 2 common antimicrobial stewardship strategies, syndrome-specific interventions and antimicrobial postprescription prospective audit and feedback (PAF), in reducing AU of APBL at a large community-teaching hospital.

METHODS

Four antimicrobial stewardship interventions targeting APBL were serially introduced, including 2 syndrome-specific interventions (bloodstream and intra-abdominal infections) and 2 PAF interventions (carbapenems and piperacillin/tazobactam). Multivariable linear regression was used to examine overall AU of APBL and audited antimicrobial agents.

RESULTS

Overall AU of APBL declined from 92.4-69.1 days of therapy (DOT) per 1,000 patient-days between February 2013 and July 2017 (P < .001). Both syndrome-specific interventions were associated with significant reduction in AU of APBL (-7.7 [95% confidence interval (CI): -11.5, -4.0] and -6.0 [95% CI: -9.7, -2.3] DOT per 1,000 patient-days) for bloodstream and intra-abdominal infections, respectively). No significant change in overall AU of APBL was observed after implementation of PAF interventions for carbapenems (-1.4 [95% CI: -7.4, 4.6] DOT per 1,000 patient-days) or piperacillin/tazobactam (0.9 [95% CI: -3.7, 5.4] DOT per 1,000 patient-days).

CONCLUSIONS

Implementation of syndrome-specific interventions was followed by significant reduction in AU of APBL in this population. Despite reducing AU of targeted agents, neither PAF intervention contributed to overall observed decline in APBL use, likely due to compensatory increase in using other APBL.

Antimicrobial stewardship intervention: optimizing antibiotic treatment in hospitalized patients with reported antibiotic allergy

BACKGROUND

Reported antibiotic allergy in hospitalized patients seems to be related to more adverse events, the use of reserve antibiotics and longer hospitalization. Most patients reporting an antibiotic allergy can be de-labelled; as such, an antimicrobial stewardship intervention was set up.

AIM

To determine the impact of reported antibiotic allergy on the antibiotic treatment of hospitalized patients, and prevent unnecessary deviation from the preferred antibiotic treatment by a proactive antimicrobial stewardship intervention.

METHODS

Hospitalized patients reporting an antibiotic allergy were included in an intervention study at a teaching hospital in the Netherlands between March and May 2019. Physicians received training and were provided with a recommendation in the electronic medical record in case the preferred antibiotic treatment was unnecessarily avoided due to the allergy label and the patient was eligible for a drug challenge.

FINDINGS

In total, 492 patients reporting an antibiotic allergy were identified, accounting for 558 hospital admissions. In 93 cases, the antibiotic allergy label interfered with the preferred antibiotic treatment. Sixty-eight of these patients were eligible for a drug challenge, and 42 patients were challenged. In 40 (95%) of these patients, no allergic reaction was observed, and the preferred antibiotic treatment was given. Two (5%) patients developed a non-severe skin reaction after a drug challenge and continued an alternative antibiotic regimen.

CONCLUSION

This antimicrobial stewardship intervention can be used to provide patients with reported antibiotic allergy labels with the preferred antibiotic treatment, and to de-label them after uneventful re-exposure to the antibiotic agent.

Penicillin Allergy Assessment and Skin Testing in the Outpatient Setting

Penicillin allergies are among of the most commonly reported allergies, yet only 10% of these patients are truly allergic. This leads to potential inadvertent negative consequences for patients and makes treatment decisions challenging for clinicians. Thus, allergy assessment and penicillin skin testing (PST) are important management strategies to reconcile and clarify labeled penicillin allergies. While PST is more common in the inpatient setting where the results will immediately impact antibiotic management, this process is becoming of increasing importance in the outpatient setting. PST in the outpatient setting allows clinicians to proactively de-label and educate patients accordingly so beta-lactam antibiotics may be appropriately prescribed when necessary for future infections. While allergists have primarily been responsible for PST in the outpatient setting, there is an increasing role for pharmacist involvement in the process. This review highlights the importance of penicillin allergy assessments, considerations for PST in the outpatient setting, education and advocacy for patients and clinicians, and the pharmacist’s role in outpatient PST.

Antimicrobial Stewardship Interventions to Combat Antibiotic Resistance: an Update on Targeted Strategies

PURPOSE OF REVIEW

Overutilization of antimicrobials is a known contributor to the development of antimicrobial resistance, which is a threat to global health. The goal of antimicrobial stewardship programs (ASPs) is to implement targeted interventions to reduce inappropriate antimicrobial prescribing and prevent development of antimicrobial resistance. We aim to review recently published literature focused on five categories of ASP interventions that have demonstrated success in optimizing appropriate antimicrobial use, improving patient outcomes, and fighting antimicrobial resistance.

RECENT FINDINGS

In the past year, ASP interventions in the published literature have focused on minimizing duration of antimicrobial therapy for infectious syndromes, implementing novel methods for performing prospective audit and feedback, utilizing microbiology laboratory or rapid diagnostic tests to expedite diagnosis, leveraging clinical decision support and electronic medical record tools, and performing penicillin allergy assessment. While the majority of studies assessing ASP interventions do not assess changes in antimicrobial resistance, outcomes demonstrating improved appropriate antibiotic use have been used as a surrogate. Successful ASPs should seek to implement and evaluate novel interventions targeting improvement in antimicrobial prescribing. Such interventions are of critical importance to prevent further growth of antimicrobial resistance.

Penicillin Allergy Skin Testing in the Inpatient Setting

The consequences of a documented penicillin allergy in the medical record are especially troublesome in acutely ill, hospitalized patients. A penicillin allergy label may lead to alternative or second line therapies resulting in adverse drug events, negative clinical outcomes and increased costs. Reconciling penicillin allergies is a necessity to facilitate early, optimal therapy and is a shared responsibility among the healthcare team. Penicillin skin testing (PST) has been utilized successfully in hospitalized patients to de-label erroneous penicillin allergies and optimize antibiotic therapy. This targeted review aims to discuss the practical development and implementation of PST in the inpatient setting. This includes a needs assessment checklist with common considerations allowing for customization to one’s institution based on available personnel, time, and technological resources.

Impact of Reported β-Lactam Allergy on Management of Methicillin-Sensitive Staphylococcus aureus Bloodstream Infections

BACKGROUND

Antistaphylococcal β-lactams antibiotics are the preferred treatment for methicillin-sensitive Staphylococcus aureus (MSSA) infections. Patient-reported β-lactam allergies may complicate antibiotic decision-making and delay optimal therapy, with potential implications on patient outcomes.

OBJECTIVE

To determine the impact of reported β-lactam allergies on the receipt of optimal therapy and outcomes for MSSA bloodstream infections (BSI).

METHODS

Retrospective, matched cohort of MSSA BSI patients with and without a reported β-lactam allergy. The primary end point was receipt of optimal therapy, defined as an antistaphylococcal β-lactam.

RESULTS

Two hundred twelve patients were included: 53 with reported β-lactam allergy and 159 without β-lactam allergy. Commonly reported β-lactam allergies were 26 (49%) immune-mediated reaction and 8 (15%) intolerance, with 19 (36%) having no documented reaction. Optimal antibiotics were given to 135 patients without a β-lactam allergy and 37 patients with a reported β-lactam allergy (85% vs 70%, P = .015). Among reported β-lactam allergy patients, those without a documented reaction were less likely to receive optimal therapy (47% vs 79%, P = .042). Reported β-lactam allergy was not associated with clinical response (P = .61) or MSSA-related mortality (P = .83). When adjusting for immunosuppression, variables independently associated with optimal therapy were β-lactam allergy (adjusted odds ratio [adjOR], 0.3; 95% confidence interval [CI], 0.1-0.6) and infectious diseases consultation (adjOR, 6.1; 95%CI, 2.7-13.9). Optimal antibiotic use was associated with decreased all-cause 90-day mortality (adjOR, 0.23; 95%CI, 0.09-0.54).

CONCLUSIONS

Patients with reported β-lactam allergies, particularly those without a documented reaction, were less likely to receive optimal antibiotics for MSSA BSI. Patient outcomes may be improved with enhanced quality of allergy history and routine infectious disease consultation.

Clinical and Economic Outcomes of Penicillin Skin Testing as an Antimicrobial Stewardship Initiative in a Community Health System

BACKGROUND

Penicillin skin testing (PST) is a novel way to reduce the use of broad-spectrum agents in penicillin-allergic patients. This study evaluated the outcomes of patients with antimicrobials prescribed with and without PST in a community health system.

METHODS

We performed a quasi-experimental study that compared an intervention group of 100 patients who completed PST over an open enrollment period beginning January 2016 with a matched control group of 100 patients who were penicillin allergic. Patients in the control group were matched to infection diagnosis codes of members of the PST group and randomly selected and matched on a 1:1 basis. The primary outcome was noncarbapenem beta-lactam days of therapy (DOT). The secondary outcome assessed the average cost of antimicrobial therapy for the intervention group before and after PST.

RESULTS

Seventy of the 98 patients (71%) who tested negative had changes directly made to their antimicrobial regimens. Beta-lactam DOT for the PST group were 666/1094 (60.88%, with 34.82% being a penicillin specifically). Beta-lactam DOT for the control group consisted of 386/984 (39.64%, with 6.4% being a penicillin specifically). The chi-square test of homogeneity for beta-lactam DOT between the 2 groups was significant (P < .00001). Changes to the antimicrobial regimen after PST saved the average patient $353.03 compared with no change in the pre-PST regimen (P = .045).

CONCLUSIONS

PST led to immediate antimicrobial de-escalation in the majority of patients who tested negative. This led to a significant increase in beta-lactam usage, specifically penicillins. These benefits were also associated with significant cost savings to patients.

The Burden and Impact of Antibiotic Prescribing in Ambulatory Pediatrics

Antibiotics are one of the most commonly prescribed classes of medication for children and adolescents. While they are arguably the most powerful tool we possess against bacterial infections, they are frequently given to children whose illnesses are due to viruses or other non-infectious etiologies. When antibiotics are not used judiciously, the consequences can be serious and accumulate over time. This review article quantifies the burden of antimicrobial use in the pediatric outpatient setting in the United States, reviews recommended first line antibiotic regimens for common outpatient pediatric and adolescent conditions, investigates the reasons for inappropriate prescribing of antibiotics in outpatient healthcare settings, and explores the range of consequences of overuse and inappropriate use of antibiotics, from adverse drug reactions to impact on the microbiome to rising rates of antimicrobial resistance in common ambulatory conditions.

Appropriateness of Beta-Lactam Allergy Record Updates After an Allergy Service Consult

BACKGROUND

Many patients with a self-reported penicillin allergy go on to tolerate beta-lactam antibiotics. Allergy specialists may be consulted to determine the nature and extent of the allergy. However, electronic allergy records must be appropriately updated such that recommendations are carried forward.

OBJECTIVE

To determine the percentage of patients who have their electronic allergy record updated after an allergy service consult (ASC).

METHODS

This was a retrospective study of patients with at least 1 documented beta-lactam allergy and had an ASC during (inpatient) or prior to (outpatient) hospital admission at Northwestern Memorial Hospital and Prentice Women's Hospital in Chicago, Illinois.

RESULTS

Within the study period, a total of 26 526 patients were identified as having a documented antibiotic allergy, with 21 657 patients (81.6% of patients with allergies) having a listed beta-lactam allergy. Of these patients, 1689 (7.8%) patients were identified as having an ASC during or prior to admission, with 598 patients meeting inclusion criteria. Changes in the allergy record were recommended by the ASC for 62% (n = 371) of patients; however, the allergy record was updated after the ASC in 74.9% (n = 278) of patients.

CONCLUSION

ASC recommendations to delabel a patient as beta-lactam allergic must result in updating the allergy record in order to optimize future treatment. Given the low proportion of allergy-labeled patients tested, programs outside formal ASCs should be considered.

The Culture of Carbapenem Overconsumption: Where Does It Begin? Results of a Single-Center Survey

Purpose: The United States has seen an increased consumption of carbapenem antibiotics in recent years. The increased utilization of these agents has potential negative consequences, including the increasing incidence of carbapenem-resistant Enterobacteriaceae. Reasons for the rise in carbapenem use among providers in acute care hospitals are not well elucidated in literature. The objectives of this study were to identify factors that influence empiric carbapenem use among providers in a single academic medical center, and to assess therapeutic knowledge pertaining to carbapenem use. Methods: A cross-sectional, single-center, 9-item electronic research survey was developed independently and validated by an infectious diseases pharmacist and infectious diseases physician. The survey was distributed to email accounts of providers at a single academic medical center. Demographic data, factors affecting carbapenem prescription, and baseline therapeutic knowledge were assessed. Results: Ninety-five of 416 providers responded to the survey (response rate of 22.8%). Respondents were well distributed across all levels of training with primary roles in internal medicine and surgery. The most important factors influencing empiric carbapenem use were suspected pathogens at the site of infection, drug allergies, history of multidrug resistant organisms, severity of illness, type of infection, and local resistance rates. A recommendation from a pharmacist was selected as the most likely factor for deterring carbapenem use. Misconceptions pertaining to penicillin drug allergy and beta-lactam cross reactivity, knowledge of local resistance rates according to the institutional antibiogram, and comparative efficacy data for carbapenems were apparent across all levels of training. Conclusions: Provider misconceptions regarding several factors appear to contribute to unnecessary use of carbapenems. An opportunity exists for hospital pharmacists to improve the prescribing patterns of carbapenems by correcting provider misconceptions through education.