Association Between Penicillin Allergy Documentation and Antibiotic Use

A call to address penicillin allergy labels in patients with hematopoietic stem cell transplants: How to avoid rash decisions

Among patients with hematopoietic stem cell transplants, infections, particularly multidrug-resistant infections, pose a grave threat. In this setting, penicillin allergy labels are both common and harmful. Though the majority of patients who report penicillin allergy can actually tolerate penicillin, penicillin allergy labels are associated with use of alternative antibiotics, which are often more broad spectrum, less effective, and more toxic. In turn, they are associated with more severe infections, multidrug-resistant infections, Clostridium difficile, and increased mortality. Evaluating penicillin allergy labels can immediately expand access to preferred therapeutic options, which are critical to care in patients with recent hematopoietic stem cell transplants. Point-of-care assessment and clinical decision tools now exist to aid the nonallergist in assessment of penicillin allergy. This can aid in expanding use of other beta-lactam antibiotics and assist in risk-stratifying patients to determine a testing strategy. In patients with low-risk reaction histories, direct oral challenges can be employed to efficiently delabel patients across clinical care settings. We advocate for multidisciplinary efforts to evaluate patients with penicillin allergy labels prior to transplantation.

Comparative Performance of 4 Penicillin-Allergy Prediction Strategies in a Large Cohort

BACKGROUND

A safe and pragmatic guide for labelling and delabelling patients with suspected penicillin allergy is mandatory.

OBJECTIVE

To compare the performance of 4 penicillin-allergy prediction strategies in a large independent cohort.

METHODS

We conducted a retrospective study for subjects presenting between January 2014 and December 2021 at the University Hospital of Montpellier, with a history of hypersensitivity to penicillins. The outcome targeted by the study was a positive penicillin-allergy test.

RESULTS

Of the 1,884 participants included, 382 (20.3%) had positive penicillin-allergy tests. The ENDA (European Network on Drug Allergy) and Blumenthal strategies yielded relatively high sensitivities and low specificities and, by design, did not misclassify any positive subjects with severe index reactions. The PEN-FAST <3 score had a negative predictive value of 90% (95% confidence interval [95% CI] 88%-91%), with a sensitivity of 66% (95% CI 62%-71%) and a specificity of 73% (95% CI 71%-75%), and incorrectly delabelled 18 subjects with anaphylaxis and 15 with other severe nonimmediate reactions. For the adapted Chiriac score, the specificity corresponding to 66% sensitivity was 73% (95% CI 70%-75%). Conversely, at a 73% specificity threshold, the sensitivity was 65% (95% CI, 61%-70%). Attempts to improve these prediction algorithms did not substantially enhance performance.

CONCLUSIONS

The ENDA and Blumenthal strategies are safe for high-risk subjects, but their delabelling effectiveness is limited, leading to unnecessary avoidance. Conversely, the PEN-FAST and Chiriac scores are performant in delabelling, but more frequently misclassify high-risk subjects with positive penicillin-allergy tests. Selection of the most appropriate tool requires careful consideration of the target population and the desired goal.

Evaluation of patients labeled with a penicillin allergy to promote antimicrobial stewardship in dental practice

BACKGROUND

Approximately 10% of the US population self-reports a penicillin allergy history or are labeled as penicillin allergic. However, from 90% through 99% of these patients are not allergic on formal evaluation.

CASE DESCRIPTION

Patients labeled as penicillin allergic receive broader-spectrum and sometimes less-effective antibiotics, thereby contributing to increased treatment failures, antibiotic resistance, and adverse drug reactions. Self-reported penicillin allergy can be eliminated or classified as low-, medium-, or high-risk after a careful review of patient history. This allows these patients to be delabeled; that is, having any reference to their penicillin allergy history or of having an allergy to penicillin eliminated from their health records.

PRACTICAL IMPLICATIONS

Oral health care professionals are ideally placed to partner in both antibiotic stewardship interventions by means of recognizing pervasive mislabeling and aiding in the process of delabeling.

Predicting Penicillin Allergy: A United States Multicenter Retrospective Study

BACKGROUND

Using the reaction history in logistic regression and machine learning (ML) models to predict penicillin allergy has been reported based on non-US data.

OBJECTIVE

We developed ML positive penicillin allergy testing prediction models from multisite US data.

METHODS

Retrospective data from 4 US-based hospitals were grouped into 4 datasets: enriched training (1:3 case-control matched cohort), enriched testing, nonenriched internal testing, and nonenriched external testing. ML algorithms were used for model development. We determined area under the curve (AUC) and applied the Shapley Additive exPlanations (SHAP) framework to interpret risk drivers.

RESULTS

Of 4777 patients (mean age 60 [standard deviation: 17] years; 68% women, 91% White, and 86% non-Hispanic) evaluated for penicillin allergy labels, 513 (11%) had positive penicillin allergy testing. Model input variables were frequently missing: immediate or delayed onset (71%), signs or symptoms (13%), and treatment (31%). The gradient-boosted model was the strongest model with an AUC of 0.67 (95% confidence interval [CI]: 0.57-0.77), which improved to 0.87 (95% CI: 0.73-1) when only cases with complete data were used. Top SHAP drivers for positive testing were reactions within the last year and reactions requiring medical attention; female sex and reaction of hives/urticaria were also positive drivers.

CONCLUSIONS

An ML prediction model for positive penicillin allergy skin testing using US-based retrospective data did not achieve performance strong enough for acceptance and adoption. The optimal ML prediction model for positive penicillin allergy testing was driven by time since reaction, seek medical attention, female sex, and hives/urticaria.

How to Define and Manage Low-Risk Drug Allergy Labels

Risk stratification in drug allergy implies that specific risk categories (eg, low, moderate, and high) classify historical drug hypersensitivity reactions. These risk categories can be based on reaction phenotypic characteristics, the timing of the reaction and evaluation, the required reaction management, and individual characteristics. Although a multitude of frameworks have been described in the literature, particularly for penicillin allergy labels, there has yet to be a global consensus, and approaches continue to vary between allergy centers. Immune-mediated drug allergies can sometimes be confirmed using skin testing, but a negative drug challenge is required to demonstrate tolerance and remove the allergy from the electronic health record ("delabel" the allergy). Even for quintessential IgE-mediated drug allergy, penicillin allergy, recent data reveal that a direct oral challenge, without prior skin testing, is an appropriate diagnostic strategy in those who are considered low-risk. Drug allergy pathogenesis and clinical manifestations may vary depending on the culprit drug, and as such, the optimal approach should be based on risk stratification that considers individual patient and reaction characteristics, the likely hypersensitivity reaction phenotype, the drug class, and the patient's clinical needs. This article will describe low-risk drug allergy labels, focusing on β-lactam and sulfonamide antibiotics, nonsteroidal anti-inflammatory drugs, iodinated contrast media, and common chemotherapeutics. This review will also address practical management approaches using currently available risk stratification and clinical decision tools.

[Precision medicine in infectious diseases]

Infectious medicine faces a variety of challenges, such as the increase in antibiotic resistance and the emergence and spread of infectious diseases fueled by climate change and globalization. Precision medicine can provide solutions to many of these challenges. Since an untargeted request for diagnostic tests can lead to test results without clinical relevance, which can increase the use of non-indicated antibiotics, the principle aimed at is: targeted diagnostics (the right test) and consideration of patient characteristics (the right person) to optimize management (the right action). At the same time, one must always decide whether empirical therapy must be immediately initiated, even if the results of the initiated diagnostics are not yet available. In addition, many new diagnostics as well as therapies have recently been developed for the rapid detection and more specific treatment of bacterial infections. Molecular genetic methods, which offer more rapid results than classical bacterial cultures, are gaining ground as new diagnostics. New therapeutics such as bacteriophages, antibodies or antibacterial peptides allow increasingly precise treatment of certain bacterial infections. Precision medicine will also play an increasingly important role in infectious medicine in the future.

Development of a Pipeline for Removing Allergy Labels in Patients Undergoing Hematopoietic Stem Cell Transplantation

Penicillin allergy is reported by 10% to 20 % of patients, but when evaluated only 1% to 2% may have a true allergy. Patients undergoing hematopoietic stem cell transplantation (HSCT) have a high likelihood of requiring beta-lactam antibiotics due to increased infection risk, which can be limited by a penicillin allergy label. When a penicillin allergy is recorded, alternatives are needed, including more expensive broader-spectrum antibiotics, with increases in drug-resistant bacteria, longer hospital stays, higher expenditures, and increases in nosocomial infections, such as Clostridium difficile colitis. This group of patients already undergoes extensive pretreatment testing and would especially benefit from allergy delabeling. This study aimed to develop a self-sustaining, low-cost pipeline between an HSCT clinic and an allergy clinic to identify and successfully delabel low-risk patients who endorse an allergy to penicillin, amoxicillin, amoxicillin-clavulanate, piperacillin-tazobactam, or ampicillin before admission to the hospital. We developed a survey to triage allergy risk, identified key stakeholders in building the pipeline, and underwent 4 plan, do, study, act (PDSA) cycles. Changes were made in each of the PDSA cycles to minimize cost and uncompensated provider time, as well as to increase patient retention throughout the pipeline by increasing appointment availability and decreasing reliance on patients to independently progress through the pathway. Of the 410 patients with planned HSCT who were screened over 11 months, 89 (21.7%) were listed as having a penicillin and/or beta lactam allergy. All but 1 (66 of 67; 98.5%) of the participants completed the survey accurately when confirmed by an allergist, and the survey was 100% accurate in predicting delabeling success in low-risk patients. Of eligible patients, 43.8% (n = 39) were successfully delabeled before their transplant date, and 97.4% of these (n = 38) have undergone HSCT to date. This pipeline is maintained by approximately 5 hours of work per week (1 hour of allergy physician time, 4 hours of nurse and/or clinical coordinator time), with no other direct costs. There is an estimated direct savings of at least $1914.93 per patient delabeled. We successfully designed and implemented a pipeline between the HSCT clinic and the allergy clinic as a quality improvement initiative to identify and address high rates of reported beta-lactam allergies. We identified and addressed patient-based factors, logistical, temporal, and financial barriers that impacted patient retention and sustainability. This model is expected to yield significant and sustained cost savings for the healthcare system as well as to improve patient outcomes, and this hypothesis is currently undergoing formal analysis. We anticipate that this model can be used to create a similar pipeline in other healthcare systems for HSCT recipients, as well as patients in other clinical settings, such as oncology and chimeric antigen receptor T cell therapy.

Penicillin Allergy Evaluation Should Be Performed Proactively in Patients With a Penicillin Allergy Label

Penicillin allergy is the most common drug allergy in the US population. A penicillin allergy label is associated with poor patient outcomes including increased hospital length of stay, increased perioperative infections, and overall increased mortality. A penicillin allergy evaluation accurately identifies approximately 9 of 10 patients who, despite reporting a history of penicillin allergy, can receive penicillins safely. Penicillin allergy evaluations should be offered proactively to healthy patients during routine visits, including children and pregnant women, in advance of antibiotic need.

A retrospective case-control study to evaluate the use of beta-lactam desensitization in the management of penicillin-allergic patients: a potential strategy for Antimicrobial Stewardship Programs

Introduction: Penicillin allergy labels (PAL) are common in the hospital setting and are associated with worse clinical outcomes. Desensitization can be a useful strategy for allergic patients when alternative options are suboptimal or not available. The aim was to compare clinical outcomes of patients with PAL managed with antibiotic desensitization vs. those who received alternative non-beta-lactam antibiotic treatments. Methods: A retrospective 3:1 case-control study was performed between 2015-2022. Cases were adult PAL patients with infection who required antibiotic desensitization; controls were PAL patients with infection managed with an alternative antibiotic treatment. Cases and controls were adjusted for age, sex, infection source, and critical or non-critical medical services. Results: Fifty-six patients were included: 14 in the desensitization group, 42 in the control group. Compared to the control group, desensitized PAL patients had more comorbidities, with a higher Charlson index (7.4 vs. 5; p = 0.00) and more infections caused by multidrug-resistant (MDR) pathogens (57.1% vs. 28.6%; p = 0.05). Thirty-day mortality was 14.3% in the desensitized group, 28.6% in the control group (p = 0.24). Clinical cure occurred in 71.4% cases and 54.8% controls (p = 0.22). Four control patients selected for MDR strains after alternative treatment; selection of MDR strains did not occur in desensitized patients. Five controls had antibiotic-related adverse events, including Clostridioides difficile or nephrotoxicity. No antibiotic-related adverse events were found in the study group. In multivariate analysis, no differences between groups were observed for main variables. Conclusion: Desensitization was not associated with worse clinical outcomes, despite more severe patients in this group. Our study suggests that antibiotic desensitization may be a useful Antimicrobial Stewardship tool for the management of selected PAL patients.

An updated review of pediatric autoimmune neuropsychiatric disorders associated with Streptococcus/pediatric acute-onset neuropsychiatric syndrome, also known as idiopathic autoimmune encephalitis: What the allergist should know

BACKGROUND

Pediatric acute-onset neuropsychiatric syndrome, further subcategorized as pediatric autoimmune neuropsychiatric disorders associated with streptococcus, is a form of idiopathic autoimmune encephalitis (IAE). Poststreptococcal autoimmunity seen in Idiopathic autoimmune encephalitis manifests as various neuropsychiatric symptoms such as obsessive rituals, tics, anxiety, depression, and many others. Idiopathic autoimmune encephalitis has clinically heterogeneous phenotypes that make accurate diagnosing difficult, although diagnostic testing such as the Cunningham Panel increases the likelihood of finding effective treatments. Current recommended treatments include psychiatric medication, behavioral intervention, antibiotics, anti-inflammatory therapy, and immunomodulating therapy.

OBJECTIVE

To provide an updated review on the diagnosis, management, and treatment of pediatric autoimmune neuropsychiatric disorder associated with streptococcus and pediatric autoimmune neuropsychiatric syndrome, also referred to as IAE.

RESULTS

Information from 47 sources was used to outline current knowledge of IAE pathophysiology, clinical manifestations, and epidemiology, and to outline diagnostic recommendations and current treatment guidelines. Gaps in knowledge, in addition to current controversy, were also outlined to provide a thorough background of this condition and future needs for IAE research.

CONCLUSION

Owing to the complexity and variability in ways patients with IAE may present to the allergist/immunologist office, an interdisciplinary approach is imperative to provide patients with the best medical care. Still, more research is needed to further elucidate the mechanism(s) and optimal treatment algorithm for IAE to facilitate broader recognition and acceptance of this condition by the medical community.

Penicillin allergy status and its effect on antibiotic prescribing, patient outcomes and antimicrobial resistance (ALABAMA): protocol for a multicentre, parallel-arm, open-label, randomised pragmatic trial

INTRODUCTION

Incorrect penicillin allergy records are recognised as an important barrier to the safe treatment of infection and affect an estimated 2.7 million people in England. Penicillin allergy records are associated with worse health outcome and antimicrobial resistance. The ALlergy AntiBiotics And Microbial resistAnce (ALABAMA) trial aims to determine if an intervention package, centred around a penicillin allergy assessment pathway (PAAP) initiated in primary care, is safe and effective in improving patient health outcomes and antibiotic prescribing.

METHODS AND ANALYSIS

The ALABAMA trial is a multicentre, parallel-arm, open-label, randomised pragmatic trial with a nested pilot study. Adults (≥18 years) with a penicillin allergy record and who have received antibiotics in the previous 24 months will be eligible for participation. Between 1592 and 2090 participants will be recruited from participating National Health Service general practices in England. Participants will be randomised to either usual care or intervention to undergo a pre-emptive PAAP using a 1:1 allocation ratio. The primary outcome measure is the percentage of treatment response failures within 28 days of an index prescription. 2090 and 1592 participants are estimated to provide 90% and 80% power, respectively, to detect a clinically important absolute difference of 7.9% in primary outcome at 1 year between groups. The trial includes a mixed-methods process evaluation and cost-effectiveness evaluation.

ETHICS AND DISSEMINATION

This trial has been approved by London Bridge Research Ethics Committee (ref: 19/LO/0176). It will be conducted in compliance with Good Clinical Practice guidelines according to the Declaration of Helsinki. Informed consent will be obtained from all subjects involved in the study. The primary trial results will be submitted for publication to an international, peer-reviewed journal.

TRIAL REGISTRATION

ISRCTN20579216.

Impact of an Inpatient Allergy Guideline on β-Lactam and Alternative Antibiotic Use

BACKGROUND

A guideline identifying when inpatients with penicillin or cephalosporin antibiotic allergy labels (PCAAL) can receive β-lactam antibiotics increased β-lactam receipt at a large northeastern US health care system.

OBJECTIVE

To report outcomes of implementing a similar guideline and electronic order set (OS) at an independent academic health care system.

METHODS

Penicillin/cephalosporin receipt (percentage of inpatients receiving full doses) and alternative antibiotic use (days of therapy per 1000 patient-days [DOT/1000PD]) were compared over 3 periods before (February 1, 2017, to January 31, 2018) and after guideline implementation (February 1, 2018, to January 31, 2019), and after OS implementation (February 1, 2019, to January 31, 2020) among inpatients with PCAAL admitted on medical services with access to guideline/OS and education (Medical-PCAAL, n = 8721), surgical services with access to guideline/OS without education (Surgical-PCAAL, n = 5069), and obstetrics/gynecology services without interventions (Ob/Gyn-PCAAL, n = 798) and inpatients without PCAAL admitted on the same services (Medical-No-PCAAL, n = 50,840; Surgical-No-PCAAL, n = 29,845; Ob/Gyn-No-PCAAL, n = 6109). χ2 tests were used to compare categorical variables, and analysis of variance was used to compare continuous and interrupted time series analyses (ITSA) to investigate the guideline/OS implementation effect on penicillin/cephalosporin receipt.

RESULTS

In the Medical-PCAAL group, penicillin/cephalosporin receipt increased (58%-68%, P < .001), specifically for cefazolin (8%-11%, P = .02) and third- to fifth-generation cephalosporins (43%-48%, P = .04), and aztreonam use decreased (12 DOT/1000PD, P = .03). In the Medical-No-PCAAL group, penicillin/cephalosporin receipt increased (88%-90%, P = .004), specifically for penicillin (40%-44%, P < .001), without changes in aztreonam use. Significant changes were not observed in these outcomes on surgical or obstetrics/gynecology services. Per ITSA, guideline/OS implementation was associated with increased penicillin/cephalosporin receipt in the Medical-PCAAL group only.

CONCLUSION

Guideline and OS implementation was associated with improved antibiotic stewardship on inpatient services that also received allergy education.

Drug Allergy Practice Parameter Updates to Incorporate Into Your Clinical Practice

The drug allergy practice parameter was developed to provide guidance on the diagnosis and management of drug hypersensitivity reactions. It was last updated in 2010. With the growth of research and evidence-based data since then, experts came together to update the practice parameter with a focus on sections that the work group deemed to have significant changes (or were not addressed) in the previous practice parameter. This review is a focused update on aspects of the practice parameter deemed to have the greatest impact on clinical practice and includes significant updates on diagnosis of antibiotic allergy including penicillin, cephalosporin, sulfonamide, fluoroquinolone, and macrolide allergies. Other topics include the evolution in our management approach to patients with aspirin/nonsteroidal anti-inflammatory drug allergy, diagnostic testing for delayed drug hypersensitivity and allergy to chemotherapeutics and biologics, and the key consensus-based statements for clinical practice. Specifically, the updated practice parameter helps allergists understand the place of 1- or 2-step drug challenges that are valuable tools often without the need for skin testing in many clinical situations. A proactive approach to delabeling penicillin allergy as well as unnecessary avoidance of safe antibiotic alternatives for patients with proven penicillin allergy is emphasized. New guidance is provided on management of patients with different phenotypes of aspirin and nonsteroidal anti-inflammatory drug hypersensitivity reactions. Approaches to delayed drug hypersensitivity and use of delayed intradermal and patch testing for specific phenotypes are reviewed. Lastly, practical approaches to management of patients with reactions to chemotherapeutics and biologics are discussed.

Low frequency of allergy referral for penicillin allergy evaluation in an urban Boston primary care setting

Background

A key strategy to combat the public health crisis of antimicrobial resistance is to use appropriate antibiotics, which is difficult in patients with a penicillin allergy label.

Objective

Our aim was to investigate racial and ethnic differences related to penicillin allergy labeling and referral to allergy/immunology in primary care.

Methods

This was a retrospective study of Tufts Medical Center's Boston-based primary care patients in 2019. Univariable and multivariable logistic regression models were used to examine demographic associations with (1) penicillin allergy label and (2) allergist referral.

Results

Of 21,918 primary care patients, 2,391 (11%) had a penicillin allergy label; of these, 249 (10%) had an allergist referral. In multivariable logistic regression models, older age (adjusted odds ratio [aOR] = 1.06 [95% CI = 1.04-1.09]) and female sex (aOR = 1.58 [95% CI = 1.44-1.74]) were associated with higher odds of penicillin allergy label carriage. Black race (aOR = 0.77 [95% CI = 0.69-0.87]) and Asian race (aOR = 0.47 [95% CI = 0.41-0.53]) were associated with lower odds of penicillin allergy label carriage. In multivariable regression, allergist referral was associated with female sex (aOR = 1.52 [95% CI = 1.10-2.10]) and Black race (aOR = 1.74 [95% CI = 1.25-2.45]). Of 93 patients (37%) who completed their allergy visit, 26 (28%) had received penicillin allergy evaluation or were scheduled to receive a penicillin allergy evaluation at a future visit.

Conclusions

There were racial differences in penicillin allergy labeling and referral. Allergy referral for penicillin allergy assessment was rare. Larger studies are needed to assess penicillin allergy labeling and delabeling with an equity focus on optimizing patient health outcomes.

Penicillin Allergy Label Is Associated With Worse Clinical Outcomes in Bacterial Pneumonia

BACKGROUND

Penicillins (PCNs) are a first-line treatment option for bacterial pneumonia. PCN allergy label can delay antimicrobial treatment and result in the use of alternative antibiotic regimens risking an inadequate response to treatment and potentially increased adverse drug reactions.

OBJECTIVE

To investigate the impact of PCN allergy label on clinical outcomes of bacterial pneumonia.

METHODS

This retrospective cohort study used TriNetX, a web-based tool for population cohort research, to identify adult patients with and without PCN allergy label diagnosed with bacterial pneumonia. Cohorts were matched for baseline demographics and chronic medical conditions. The 30-day risks of hospitalization, acute respiratory failure, intubation, need for intensive level of care, and mortality were compared. Antibiotics used and their possible adverse reactions were explored.

RESULTS

After matching, there were 68,748 patients in each cohort. Patients with bacterial pneumonia with PCN allergy label had higher risks of hospitalization (risk ratio [RR], 1.23; 95% confidence interval [CI], 1.22-1.24), acute respiratory failure (RR, 1.14; 95% CI, 1.12-1.15), intubation (RR, 1.18; 95% CI, 1.13-1.22), intensive level of care (RR, 1.11; 95% CI, 1.08-1.14), and mortality (RR, 1.08; 95% CI, 1.04-1.13) compared with patients without PCN allergy label. Patients with PCN allergy label had decreased use of PCNs and cephalosporins and increased utilization of other antibiotic classes compared with patients without PCN allergy label. PCN allergy label was also associated with increased risk of adverse drug reactions.

CONCLUSION

PCN allergy label is associated with worse clinical outcomes in bacterial pneumonia, and risk mitigation strategies should be considered.

Improving antimicrobial stewardship with penicillin allergy testing: a review of current practices and unmet needs

Penicillin allergy, the most frequently reported drug allergy, has been associated with suboptimal antibiotic therapy, increased antimicrobial resistance, increased rates of Clostridioides difficile colonization and infection, as well as extended hospital length of stay and increased cost. Although up to 10% of all patients may report penicillin allergy, most penicillin allergies are not confirmed. As such, most patients with a penicillin allergy can still safely use penicillin and related drugs following a more precise assessment. Herein, we review the current practices and unmet needs in penicillin allergy testing. The diagnostic algorithm is mostly based on a clinical history assessment followed by in vivo testing, i.e. skin test and/or drug challenge. As these tests are labour and resource intensive, there is increased interest in point-of-care penicillin allergy de-labelling solutions incorporated into Antimicrobial Stewardship Programmes including digital assessment tools. These can be locally parameterized on the basis of characteristics of target populations, incidence of specific allergies and local antibiotic usage to perform clinical risk stratification. Safely ruling out any residual risk remains essential and in vivo drug challenge and/or skin testing should be systematically encouraged. Gradual understanding and convergence of the risk stratification of the clinical presentation of penicillin allergy is enabling a wider implementation of this essential aspect of antimicrobial stewardship through digitalized decision tools and in vivo testing. More research is needed to deliver point of care in vitro diagnostic tools to democratize this de-labelling practice, which would be highly beneficial to patient care. This progress, together with better education of patients and clinicians about the availability, efficacy and safety of penicillin allergy testing, will increase the dissemination of penicillin allergy assessment as an important component of Antimicrobial Stewardship Programmes.

Hong Kong Drug Allergy Delabelling Initiative (HK-DADI) consensus statements for penicillin allergy testing by nonallergists

Introduction

Penicillin allergy testing has been traditionally performed by allergists, but there remains a huge deficit of specialists. A multidisciplinary effort with nonallergists would be invaluable to overcome the magnitude of penicillin allergy labels via the Hong Kong Drug Allergy Delabelling Initiative (HK-DADI). These consensus statements (CSs) offer recommendations and guidance to enable nonallergists to screen for low-risk (LR) patients and perform penicillin allergy testing.

Methods

CSs were formulated by the HK-DADI Group using the Delphi method. An agreement was defined as greater than or equal to 80% consensus.

Results

A total of 26 CSs reached consensus after multiple rounds of Delphi. CSs were categorized into risk assessment, skin testing, drug provocation testing (DPT), and post-testing management. For risk assessment, the essentials of allergy history and exclusion criteria were detailed. Patients with only LR features can proceed with testing by nonallergists. Skin tests should be performed prior to DPT. Details regarding the timing, preparation, and interpretation of skin tests were elaborated. DPT remains the gold standard to diagnose genuine allergy or tolerance and should be performed when there is a low pretest probability following negative skin testing. Details of DPT preparations, dosing protocols, and interpretation were elaborated. For post-testing management, inaccurate allergy labels should be delabeled following negative DPT with proper patient counseling.

Conclusion

CSs support penicillin allergy testing by nonallergists in Hong Kong. LR cases can be managed by nonallergists at Spoke Clinics, with training and support of an allergist-led Hub.

Standards for practical intravenous rapid drug desensitization & delabeling: A WAO committee statement

Drug hypersensitivity reactions (DHRs) to intravenous drugs can be severe and might leave patients and doctors in a difficult position where an essential treatment or intervention has to be suspended. Even if virtually any intravenous medication can potentially trigger a life-threatening DHR, chemotherapeutics, biologics, and antibiotics are amongst the intravenous drugs most frequently involved in these reactions. Admittedly, suspending such treatments may negatively impact the survival outcomes or the quality of life of affected patients.

Delabeling pathways and rapid drug desensitization (RDD) can help reactive patients stay on first-choice therapies instead of turning to less efficacious, less cost-effective, or more toxic alternatives. However, these are high-complexity and high-risk techniques, which usually need expert teams and allergy-specific techniques (skin testing, in vitro testing, drug provocation testing) to ensure safety, an accurate diagnosis, and personalized management. Unfortunately, there are significant inequalities within and among countries in access to allergy departments with the necessary expertise and resources to offer these techniques and tackle these DHRs optimally.

The main objective of this consensus document is to create a great benefit for patients worldwide by aiding allergists to expand the scope of their practice and support them with evidence, data, and experience from leading groups from around the globe.

This statement of the Drug Hypersensitivity Committee of the World Allergy Organization (WAO) aims to be a comprehensive practical guide on the technical aspects of implementing acute-onset intravenous hypersensitivity delabeling and RDD for a wide range of drugs. Thus, the manuscript does not only focus on clinical pathways. Instead, it also provides guidance on topics usually left unaddressed, namely, internal validation, continuous quality improvement, creating a healthy multidisciplinary environment, and redesigning care (including a specific supplemental section on a real-life example of how to design a dedicated space that can combine basic and complex diagnostic and therapeutic techniques in allergy).

Documented β-Lactam Allergy and Risk for Cesarean Surgical Site Infection

Objective. To examine the relationship between documented β-lactam allergy and cesarean delivery (CD) surgical site infection (SSI). Study Design. We conducted a retrospective cohort analysis of women who underwent CD at Ben Taub Hospital and Texas Children’s Pavilion for Women (Houston, TX) from August 1, 2011, to December 31, 2019. The primary exposure was a documented β-lactam allergy, and the second exposure of interest was the type of perioperative antibiotic received. The primary outcome was the prevalence of SSI. Maternal characteristics were stratified by the presence or absence of a documented β-lactam allergy, and significance was evaluated using Pearson’s chi-squared test for categorical variables and $t$ -test for continuous variables. A logistic regression model estimated odds of SSI after adjusting for possible confounders. Results. Of the 12,954 women included, 929 (7.2%) had a documented β-lactam allergy while 12,025 (92.8%) did not. Among the 929 women with a β-lactam allergy, 495 (53.3%) received non-β-lactam perioperative prophylaxis. SSI occurred in 38 (4.1%) of women who had a β-lactam allergy versus 238 (2.0%) who did not ( $p\le 0.001$ ). β-Lactam allergy was associated with higher odds of SSI compared to no allergy ( $\text{adjusted}\text{odds}\text{ratio}\left(\text{aOR}\right)=1.97$ ; $95\%\text{confidence}\text{interval}\left(\text{CI}\right)=1.24$ -3.14; $p=0.004$ ) after controlling for age, race, ethnicity, insurance status, delivery body mass index (BMI), tobacco use, intra-amniotic infection in labor, duration of membrane rupture, preterm delivery, delivery indication, diabetes, hypertension, group B Streptococcus colonization, and type of perioperative antibiotic received. Conclusion. The presence of a β-lactam allergy is associated with increased odds of developing a CD SSI after controlling for possible confounders, including the type of perioperative antibiotic received.

Improving Antibiotic Stewardship for Inpatients with Reported Beta-Lactam Allergies and Limited Access to Penicillin Skin Testing

BACKGROUND

Penicillin allergy is commonly reported, but true allergy is rare. Inpatients with reported beta-lactam allergy are often treated with alternative antibiotics. Penicillin skin testing (PST) is not universally available for inpatients.

METHODS

We designed a four-phase quality improvement project aimed to increase the percentage of inpatients on medical services with reported beta-lactam allergy who safely receive beta-lactam antibiotics at two hospitals with limited access to PST. First, we updated our hospital guideline to allow for cephalosporin graded challenge without antecedent PST. Second, we educated physicians, physician assistants, and nurses about the new guideline and beta-lactam allergy classification and management. Third, we designed a pocket card to reinforce the education. Last, we used antimicrobial stewardship software to screen our daily census to identify opportunities to improve management of patients with reported beta-lactam allergies.

RESULTS

We observed a 29.2% increase in the percentage of patients who received beta-lactam antibiotics (excluding carbapenems) among those with reported beta-lactam allergy, from 42.2% (470/1,115) at baseline to 54.5% (379/696), p < 0.001, during the project period. There was a decrease in the use of alternative antibiotics, no change in hospital-onset Clostridioides difficile cases, and no increase in the number of infectious disease or allergy consults. The number of graded challenges increased during the project period, without any anaphylaxis events.

CONCLUSION

A multiphase quality improvement project aimed to improve management of beta-lactam allergies and access to graded challenges led to an increase in beta-lactam utilization without an increase in anaphylaxis, even with limited access to PST.

The effects of beta-lactam allergy relabeling on antibiotic prescribing practices

BACKGROUND

Beta-lactam antibiotic allergy labels are highly prevalent but rarely indicate an allergic intolerance. These patient-reported allergies lead to broad-spectrum antibiotic use, conferred resistance, increased expense, and adverse effects.

OBJECTIVE

To implement and assess the impact of a history-based clinical guideline that directs antibiotic management and beta-lactam allergy relabeling for patients reporting beta-lactam allergies.

METHODS

Patients with beta-lactam allergy labels were identified by our trained multidisciplinary team in diverse clinical settings. This quality improvement project was conducted to evaluate the safety and impact of the guideline on antibiotic use by comparing prescribing practices before and after guideline implementation.

RESULTS

A total of 79 patients with beta-lactam allergies were identified (penicillins-90%, cephalosporins-10%). After guideline implementation, outcomes of allergy relabeling included the following: (1) complete removal, indicating an unlikely true allergy (27%); (2) updated to detail successfully tolerated beta-lactam courses (48%); or (3) no change made to current label (25%). Beta-lactam antibiotic courses before and after guideline implementation compared with total antibiotic courses: allergy removed (44% vs 70%; P < .001), allergy updated (32% vs 68%; P < .001), and no change (27% vs 41%; P = .08). Compared with before guideline implementation, beta-lactam antibiotics were 3 times more likely to be prescribed after allergy assessment (odds ratio, 3.22; 95% confidence interval, 2.4-4.3; P < .05).

CONCLUSION

The implementation of the beta-lactam allergy clinical guideline resulted in most patients' allergy labels being removed or advantageously updated. These allergy label changes correlated with a substantial increase in the percentage of beta-lactam antibiotics prescribed. After guideline implementation, beta-lactam antibiotics had a 3-fold increased odds of being prescribed independent of allergy label outcome.

Vancomycin Advanced Therapeutic Drug Monitoring: Exercise in Futility or Virtuous Endeavor to Improve Drug Efficacy and Safety?

Vancomycin is commonly prescribed to hospitalized patients. Decades of pharmacokinetic/pharmacodynamic research culminated in recommendations to monitor the ratio of the area under the concentration-time curve (AUC) to the minimum inhibitory concentration in order to optimize vancomycin exposure and minimize toxicity in the revised 2020 guidelines. These guideline recommendations are based on limited data without high-quality evidence and limitations in strength. Despite considerable effort placed on vancomycin therapeutic drug monitoring (TDM), clinicians should recognize that the majority of vancomycin use is empiric. Most patients prescribed empiric vancomycin do not require it beyond a few days. For these patients, AUC determinations during the initial days of vancomycin exposure are futile. This added workload may detract from high-level patient care activities. Loading doses likely achieve AUC targets, so AUC monitoring after a loading dose is largely unnecessary for broad application. The excessive vancomycin TDM for decades has been propagated with limitations in evidence, and it should raise caution on contemporary vancomycin TDM recommendations.

Association of Penicillin or Cephalosporin Allergy Documentation and Antibiotic Use in Hospitalized Patients with Pneumonia

BACKGROUND

Treatment guidelines for pneumonia recommend beta-lactam antibiotic-based therapy. Although reported penicillin allergy is common, more than 90% of patients with reported penicillin allergy are not allergic.

OBJECTIVE

We evaluated the association of a documented penicillin and/or cephalosporin (P/C) allergy to antibiotic use for the treatment of inpatient pneumonia.

METHODS

This was a national cross-sectional study conducted among Vizient, Inc., network hospitals that voluntarily contributed data. Among hospitalized patients with pneumonia, we examined the relation of a documented P/C allergy in the electronic health record to prevalence of first-line beta-lactam antibiotic administration and alternative antibiotics using multivariable log-binomial regression with generalized estimating equations.

RESULTS

Of 2,276 inpatients receiving antibiotics for pneumonia at 95 U.S. hospitals, 450 (20%) had a documented P/C allergy. Compared with pneumonia patients without a documented P/C allergy, patients with a documented P/C allergy had reduced prevalence of first-line beta-lactam antibiotic use (adjusted prevalence ratio [aPR] 0.79; 95% confidence interval [95% CI] 0.69-0.89]). Patients with high-risk P/C reactions (n = 91) had even lower prevalence of first-line beta-lactam antibiotic use (aPR 0.47; 95% CI 0.35-0.64). Alternative antibiotics associated with a higher use in pneumonia patients with a documented P/C allergy included carbapenems (aPR 1.61; 95% CI 1.22-2.13) and fluoroquinolones (aPR 1.52; 95% CI 1.21-1.91).

CONCLUSIONS

Inpatients with documented P/C allergy and pneumonia were less likely to receive recommended beta-lactams and more likely to receive carbapenems and fluoroquinolones. Inpatient allergy assessment may improve optimal antibiotic therapy for the 20% of inpatients with pneumonia and a documented P/C allergy.

Safety and efficacy of de-labelling penicillin allergy in adults using direct oral challenge: a systematic review

Background

Approximately 10% of people have an unverified penicillin allergy, with multiple personal and public health consequences.

Objectives

To assess the efficacy and safety of direct oral challenge, without prior skin testing, in this population.

Methods

MEDLINE, EMBASE, CINAHL, the Cochrane Library and Google Scholar were searched from inception to 28 June 2020 (updated November 2020) to find published and unpublished studies that reported direct oral challenge for the purpose of removal of penicillin allergy labels. Population weighted mean was used to calculate the proportion of patients who developed an immediate or delayed reaction to direct oral challenge across the studies.

Results

Thirteen studies were included in the review, with a sample size of 1202 (range 7–328). Studies included inpatient and outpatient cohorts assessed as low risk for true allergy. In pooled analysis of all 13 studies there were 41/1202 (3.41%) mild immediate or delayed reactions to direct oral challenge. The population-weighted mean incidence of immediate or delayed reaction to an oral challenge across studies was also 3.41% (95% CI: 2.38%–4.43%). There were no reports of serious adverse reactions, 96.5% of patients could be de-labelled and many were subsequently successfully treated with penicillin.

Conclusions

Direct oral challenge is safe and effective for de-labelling patients assessed as low risk for true allergy. Non-specialist clinicians competent in using an assessment algorithm can offer evaluation of penicillin allergy labels using direct oral challenge in appropriate patients. These measures will facilitate optimal infection treatment for patients, support antimicrobial stewardship, and minimize antimicrobial resistance.

Aktuelle Entwicklungen im Bereich Antibiotic Stewardship

Antibiotikaverbrauch in Deutschland In Deutschland wurden in den letzten Jahren sowohl im Krankenhausbereich als auch im ambulanten Setting immer weniger Fluorchinolone verordnet. Auch der Verbrauch der Cephalosporine ging etwas zurück.

Renaissance von Aminoglykosiden? Die inzwischen relativ seltenen Substanzen können aufgrund einer recht guten Resistenzlage bei Harnwegsinfektionen als geeignete Alternative – allerdings nur parenteral – eingesetzt werden. Bei akuten schweren Infektionen ist eine einmalige Gabe, z. B. von Tobramycin, initial zusätzlich zu einem geeigneten Betalactam ebenfalls eine Option, aber keine klare Empfehlung.

Antibiotikaeinsatz in der Hämatologie/Onkologie Bei Fieber und Neutropenie gilt nach wie vor die initiale empirische Gabe von Piperacillin-Tazobactam oder einem pseudomonasaktiven Carbapenem als Standard. Diese Betalactame sollten mit verlängerter Infusionsdauer, z. B. über 4 h, verabreicht werden. Linezolid ist ein Reservemedikament und sollte auch bei hämatoonkologischen Patienten nicht empirisch, sondern nur in der gezielten Therapie verwendet werden.

Penicillinallergie Die anamnestische Angabe einer Penicillinallergie sollte durch genaues Hinterfragen differenziert werden. Patienten können so bezüglich ihres Risikos für allergische Reaktionen gruppiert werden – oft besteht kein oder ein sehr geringes Risiko bei einer (erneuten) Behandlung mit Penicillinderivaten. Niedrigrisikopatienten dürfen ohne weitergehende allergologische Untersuchungen reexponiert werden.