Development and Validation of a Penicillin Allergy Clinical Decision Rule

Candent issues in pneumonia. Reflections from the Fifth Annual Meeting of Spanish Experts 2023

Pneumonia is a multifaceted illness with a wide range of clinical manifestations, degree of severity and multiple potential causing microorganisms. Despite the intensive research of recent decades, community-acquired pneumonia remains the third-highest cause of mortality in developed countries and the first due to infections; and hospital-acquired pneumonia is the main cause of death from nosocomial infection in critically ill patients. Guidelines for management of this disease are available world wide, but there are questions which generate controversy, and the latest advances make it difficult to stay them up to date. A multidisciplinary approach can overcome these limitations and can also aid to improve clinical results. Spanish medical societies involved in diagnosis and treatment of pneumonia have made a collaborative effort to actualize and integrate last expertise about this infection. The aim of this paper is to reflect this knowledge, communicated in Fifth Pneumonia Day in Spain. It reviews the most important questions about this disorder, such as microbiological diagnosis, advances in antibiotic and sequential therapy, management of beta-lactam allergic patient, preventive measures, management of unusual or multi-resistant microorganisms and adjuvant or advanced therapies in Intensive Care Unit.

Oral challenge vs routine care to assess low-risk penicillin allergy in critically ill hospital patients (ORACLE): a pilot safety and feasibility randomised controlled trial

PURPOSE

Critically ill patients are vulnerable to penicillin allergy labels that may be incorrect. The validity of skin testing in intensive care units (ICUs) is uncertain. Many penicillin allergy labels are low risk, and validated tools exist to identify those amenable to direct oral challenge. This pilot randomised controlled trial explored the feasibility, safety, and validity of direct enteral challenge for low-risk penicillin allergy labels in critical illness.

METHODS

Consenting patients with a low-risk penicillin allergy label (PAL) (PEN-FAST risk assessment score < 3) in four ICUs (Melbourne, Australia) were randomised 1:1 to penicillin (250 mg amoxicillin or implicated penicillin) direct enteral challenge versus routine care (2-h post-randomisation observation for each arm). Repeat challenge was performed post -ICU in the intervention arm. Patients were reviewed at 24 h and 5 days after each challenge/observation.

RESULTS

We screened 533 patients. 130 (24.4%) were eligible and 80/130 (61.5%) enrolled (age median 64.5 years (interquartile range, IQR 53.5, 74), PEN-FAST median 1 (IQR 0,1)), with 40 (50%) randomised to direct enteral challenge. A positive challenge rate of 2.5% was identified. No antibiotic-associated serious adverse events were identified. 32/40 (80%) received a repeat challenge (zero positive). Post-randomisation, 13 (32%) of the intervention arm and 4 (10%) of the control arm received penicillin (odds ratio, OR 4.33 [1.27, 14.78] p = 0.019).

CONCLUSION

These findings support the safety, validity, and feasibility of direct enteral challenge for critically ill patients with PEN-FAST assessed low-risk penicillin allergy. The absence of false negative results was confirmed by subsequent negative repeat challenges. A relatively low recruitment to screened ratio suggests that more inclusive eligibility criteria and integration of allergy assessment into routine ICU processes are needed to optimise allergy delabelling in critical illness.

Predictive models and applicability of artificial intelligence-based approaches in drug allergy

PURPOSE OF REVIEW

Drug allergy is responsible for a huge burden on public healthcare systems, representing in some instances a threat for patient's life. Diagnosis is complex due to the heterogeneity of clinical phenotypes and mechanisms involved, the limitations of in vitro tests, and the associated risk to in vivo tests. Predictive models, including those using recent advances in artificial intelligence, may circumvent these drawbacks, leading to an appropriate classification of patients and improving their management in clinical settings.

RECENT FINDINGS

Scores and predictive models to assess drug allergy development, including patient risk stratification, are scarce and usually apply logistic regression analysis. Over recent years, different methods encompassed under the general umbrella of artificial intelligence, including machine and deep learning, and artificial neural networks, are emerging as powerful tools to provide reliable and optimal models for clinical diagnosis, prediction, and precision medicine in different types of drug allergy.

SUMMARY

This review provides general concepts and current evidence supporting the potential utility of predictive models and artificial intelligence branches in drug allergy diagnosis.

What's Hot This Year in Infectious Diseases Clinical Science

The field of infectious diseases saw numerous exciting advances in 2023. Trials of new antibiotics and treatment regimens sought to address rising rates of antimicrobial resistance. Other studies focused on the most appropriate use of currently available treatments, balancing the dual goals of providing effective treatment and impactful antimicrobial stewardship. Improvements in disease prevention were made through trials of both new vaccines and new chemoprophylaxis approaches. Concerning trends this year included increasing rates of invasive group A streptococcal infections, medical tourism-associated cases of fungal meningitis, and the return of locally acquired malaria to the United States. This review covers some of these notable trials and clinical developments in infectious diseases in the past year.

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.

Beta-lactam antibiotics administration among adult inpatients with a beta-lactam allergy label: incidence, predictors, and outcomes

Background

A beta-lactam antibiotics (BLA) allergy label is common, resulting in disadvantageous outcomes due to the usage of second-line antimicrobial agents. Noncontrolled case-series analyses report low rates of hypersensitivity reactions, following intentional/non-intentional BLA challenges among labeled inpatients. The study aims were to explore predictors and outcomes associated with hypersensitivity reactions following BLA challenge among BLA-allergic labeled inpatients.

Methods

Retrospective cohort study (2019-2020) of adult (≥18 years) inpatients (Shamir Medical Center, Israel), labeled as allergic to ≥1 BLA, who received ≥1 dose/s of BLA during their stay. Independent predictors to develop allergic reactions and the independent associations of allergic reactions with clinical outcomes were queried by logistic and Cox regressions.

Results

Of 9,670 inpatients (14,088 hospitalizations), 3,570 (37%) were labeled as allergic to ≥1 BLA. Of those, 1,171 (33%) patients received ≥1 BLA. The majority were women (67%), and the mean age was 69.3 ± 19.4 years. Only 30 patients (2.6%) developed a reaction, all mild. Independent predictors to develop an allergic reaction were documented reactions in the past, atopic background, antihistamines administration prior to the BLA challenge, and high risk for cross-reactivity, based on the BLA side chains, between the labeled and the challenged agents. Reaction upon the BLA challenge was not independently associated with any worse outcome.

Conclusions

Despite the commonality of allergy labeling, and the commonality of BLA administration to labeled inpatients, hypersensitivity reactions were mild and rare. Interventional stewardship strategies for active BLA de-labeling among low-risk patients should be promoted, to improve patients' and institutional health and fiscal outcomes.

A novel 2-step process for the management of inpatient beta-lactam allergy labels

BACKGROUND

Inpatient beta-lactam allergy labels may increase the unnecessary use of aztreonam and non-beta-lactam antibiotics, which can then lead to more adverse events and increased health care costs, OBJECTIVE: To assess the impact of a novel 2-step process (medication history review followed by risk stratification) on rates of beta-lactam delabeling, aztreonam use, and desensitizations on pediatric, adult, and obstetrics inpatients at a tertiary academic center.

METHODS

We prospectively collected data on 700 patients who received inpatient consultation from the Beta-Lactam Allergy Evaluation Service between August 2021 and July 2022. Patients were delabeled either by medication review alone, drug challenge alone if with a low-risk history, or penicillin skin test followed by drug challenge if with a high-risk history. Generalized linear regression modeling was used to compare aztreonam days of therapy in the intervention year with the 2 prior years. Drug desensitizations were assessed by electronic chart review.

RESULTS

Most of the patients (n = 656 of 700, 94%) had more than or equal to 1 beta-lactam allergy label removed, clarified, or both; 77.9% of these patients (n = 511 of 656) had 587 beta-lactam allergy labels removed. Nearly one-third (n = 149, 27.6%) had 162 allergy labels removed solely by medication history review. All 114 penicillin skin tests performed had negative results, and 98% (8 of 381) of the patients who underwent any drug challenge passed. Only 5.7% of the delabeled patients were relabeled. There was a 27% reduction in aztreonam use (P = .007). Beta-lactam desensitizations were reduced by 80%.

CONCLUSION

A full-time inpatient beta-lactam allergy service using medication history review and risk stratification can safely and effectively remove inpatient beta-lactam allergy labels, reduce aztreonam use, and decrease beta-lactam desensitizations.

Characterization of invasive Group B Streptococcus isolates from Western Australian infants, 2004-2020

Background. Invasive Group B Streptococcus (GBS; Streptococcus agalactiae) remains a leading cause of infant morbidity and mortality. Intrapartum antibiotic prophylaxis (IAP) has been implemented in many countries with a reduction in early-onset disease, but an effective vaccine may further reduce the disease burden. Candidate vaccines targeting capsular polysaccharides and surface proteins are now in clinical trials.Methods. Using whole-genome sequencing and phenotypic antimicrobial susceptibility testing, we characterized sterile-site GBS isolates recovered from Western Australian infants between 2004 and 2020. Characteristics were compared between three time periods: 2004-2008, 2009-2015 and 2016-2020.Results. A total of 135 isolates were identified. The proportion of serotype III (22.7 % in Period 1 to 47.9 % in Period 3, P=0.04) and clonal complex 17 (13.6-39.6 %, P=0.01) isolates increased over time. Overall coverage of vaccines currently being trialled was >95 %. No isolates were penicillin resistant (MIC>0.25 mg l-1), but 21.5 % of isolates had reduced penicillin susceptibility (MIC>0.12 mg l-1) and penicillin MIC increased significantly over time (P=0.04). Clindamycin resistance increased over time to 45.8 % in the latest period.Conclusions. Based on comprehensive characterization of invasive infant GBS in Western Australia, we found that coverage for leading capsular polysaccharide and surface protein vaccine candidates was high. The demonstrated changes in serotype and molecular type highlight the need for ongoing surveillance, particularly with regard to future GBS vaccination programmes. The reduced susceptibility to IAP agents over time should inform changes to antibiotic guidelines.

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.

Comprehensive Nomograms Using Routine Biomarkers Beyond Eosinophil Levels: Enhancing Predictability of Corticosteroid Treatment Outcomes in AECOPD

Purpose

Patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) exhibit heterogeneous responses to corticosteroid treatment. We aimed to determine whether combining eosinophil levels with other routine clinical indicators can enhance the predictability of corticosteroid treatment outcomes and to come up with a scoring system.

Patients and Methods

Consecutive patients admitted with AECOPD receiving corticosteroid treatment between July 2013 and March 2022 at Beijing Chao-Yang Hospital were retrospectively analyzed. Data on patients' demographics, smoking status, hospitalization for AECOPD in the previous year, comorbidities, blood laboratory tests, in-hospital treatment and clinical outcomes were collected. Least absolute shrinkage and selection operator (LASSO) regression and backward logistic regression were used for predictor selection, and predictive nomograms were developed. The discrimination and calibration of the nomograms were assessed using the area under the receiver operating curve (AUC) and calibration plots. Internal validation was performed using the 500-bootstrap method, and clinical utility was evaluated using decision curve analysis (DCA).

Results

Among the 3254 patients included, 804 (24.7%) had treatment failure. A nomogram of eosinophils, platelets, C-reactive protein (CRP), low density lipoprotein cholesterol, prognostic nutritional index (PNI), hospitalization for AECOPD in the previous year, ischemic heart diseases and chronic hepatic disease was developed to predict treatment failure for patients with a smoking history. For patients without a smoking history, a nomogram of CRP, PNI, ischemic heart diseases and chronic hepatic disease was developed. Although the AUCs of these two nomograms were only 0.644 and 0.647 respectively, they were significantly superior to predictions based solely on blood eosinophil levels.

Conclusion

We developed easy-to-use comprehensive nomograms utilizing readily available clinical biomarkers related to inflammation, nutrition and immunity, offering modestly enhanced predictive value for treatment outcomes in corticosteroid-treated patients with AECOPD. Further investigations into novel biomarkers and additional patient data are imperative to optimize the predictive performance.

Impact of penicillin allergy records on antimicrobial prescribing in hospitalised patients

BACKGROUND

The overdiagnosis of penicillin allergy and misclassification of non-truly allergic reactions is a growing public health problem, associated with the overuse of broad-spectrum and restricted antimicrobials. We aimed to evaluate the impact of penicillin allergy status on antimicrobial prescribing.

METHODS

A retrospective study of inpatients with a documented penicillin allergy receiving antimicrobials was conducted from 1 April to 1 July 2021. Antimicrobial prescribing and clinical characteristics were compared between patients with an active penicillin allergy label and those whose label was removed following antimicrobial stewardship team review. Antimicrobials were classified in two categories: i) 'Access' (recommended), ii) 'Watch and Reserve' (restricted) according to WHO AWaRe classification, a tool to guide appropriate antibiotic use.

RESULTS

437 patients with a documented penicillin allergy receiving antimicrobials were included. 353 patients with an active penicillin allergy label, more frequently received antimicrobials from the 'Watch and Reserve list' (283;80% vs 30;37%; p<0.001). In contrast, 84 patients who were de-labelled received more often antimicrobials from the 'Access list' (53;63% vs 64;18%; p<0.001).

CONCLUSIONS

Penicillin allergy reviews and de-labelling strategies may reduce the use of restricted antimicrobials under the 'Watch and Reserve list'. This practice should be encouraged and reinforced in all hospitals.

How to manage drug-virus interplay underlying skin eruptions in children

The majority of viral rashes occurring during an antibiotic therapy are considered as a drug hypersensitivity reaction (DHR). Differentiating a viral rash versus a DHR is difficult or even impossible. In delayed DHRs the interplay between viruses and drugs is summarized according to the recent literature. The question is if the same reaction will again occur in case of drug re-exposure in absence of the concomitant viral infection because of persistent immune reactivity. Epstein Barr Virus (EBV) and Human Herpes virus 6 (HHV-6) models are analyzed in case of maculopapular exanthemas (MPEs) and drug reaction with eosinophilia and systemic symptoms (DRESS) over a course of drug therapy. MPEs are the most common skin manifestation during a viral infection and a concomitant drug therapy. In type IVb reactions to drugs a hapten/pro-hapten mechanism and a pharmacological interaction (p-i mechanism) are described as the 2 major ways to make T cells response functional. Rarely the altered repertoire model is involved. The Human Leukocyte Antigen (HLA) predisposition is an additional essential factor that can facilitate DHR. In MPEs rarely a DHR is confirmed by allergy testing. Severity and duration of MPEs, the presence of eosinophilia and systemic symptoms make more reliable the persistent nature of the reaction. Research on this topic is needed in order to provide the clinicians with instruments to decide when to suspect future reactions upon drug re-exposure even in the absence of a viral infection, because those patients should be investigated by a complete drug allergy work up.

A multicentre observational study to investigate feasibility of a direct oral penicillin challenge in de-labelling 'low risk' patients with penicillin allergy by non-allergy healthcare professionals (SPACE study): Implications for healthcare systems

OBJECTIVE

The huge burden of inaccurate penicillin allergy labels (PALs) is an important driver of antimicrobial resistance. This is magnified by insufficient allergy specialists and lack of 'point-of-care' tests. We investigated the feasibility of non-allergy healthcare professionals (HCPs) delivering direct oral penicillin challenges (DPCs) for penicillin allergy de-labelling.

METHODS

This prospective observational study was conducted in three hospitals in England across three settings (acute medical, pre-surgical and haematology-oncology). Patients with a PAL were screened and stratified as low risk/high risk. Low risk patients (non-immune mediated symptoms, benign rash, tolerated amoxicillin since and family history) underwent a DPC.

RESULTS

N = 2257 PALs were screened, 1054 were eligible; 643 were approached, 373 declined, 270 consented and 259 risk stratified (low risk = 155; high risk = 104). One hundred and twenty-six low risk patients underwent DPC, 122 (96.8%) were de-labelled with no serious allergic reactions. Conversion rate from screening-to-consent was 12% [3.3% and 17.9% in acute and elective settings respectively; odds ratios for consent were 3.42 (p < 0.001) and 5.53 (p < 0.001) in haematology-oncology and pre-surgical setting respectively. Common reasons for failure to progress in the study included difficulty in reaching patients, clinical instability/medical reasons, lacking capacity to consent and psychological factors.

INTERPRETATION

DPCs can be delivered by non-allergy HCPs. A high proportion of patients with PALs did not progress in the study pathway. Strategies to deliver DPC at optimal points of the care pathway are needed to enhance uptake. Elective settings offer greater opportunities than acute settings for DPC. The safety and simplicity of DPCs lends itself to adoption by healthcare systems beyond the UK, including in resource-limited settings.

EAACI/ENDA position paper on drug provocation testing

In drug hypersensitivity, drug provocation testing (DPT), also called drug challenge, is the gold standard for investigation. In recent years, risk stratification has become an important tool for adjusting the diagnostic strategy to the perceived risk, whilst still maintaining a high level of safety for the patient. Skin tests are recommended before DPT but may be omitted in low-risk patients. The task force suggests a strict definition of such low-risk patients in children and adults. Based on experience and evidence from studies of allergy to beta-lactam antibiotics, an algorithm on how to adjust DPT to the risk, and when to omit skin tests before DPT, is presented. For other antibiotics, non-steroidal anti-inflammatory drugs and other drugs, skin tests are poorly validated and DPT is frequently necessary. We recommend performing DPT with chemotherapeutics and biologicals to avoid unnecessary desensitization procedures and DPT with skin tests negative contrast media. We suggest DPT with anesthetics only in highly specialized centers. Specifics of DPT to proton pump inhibitors, anticonvulsants and corticosteroids are discussed. This position paper provides general recommendations and guidance on optimizing use of DPT, whilst balancing benefits with patient safety and optimizing the use of the limited available resources.

Sepsis Stewardship: The Puzzle of Antibiotic Therapy in the Context of Individualization of Decision Making

The main recent change observed in the field of critical patient infection has been universal awareness of the need to make better use of antimicrobials, especially for the most serious cases, beyond the application of simple and effective formulas or rigid protocols. The increase in resistant microorganisms, the quantitative increase in major surgeries and interventional procedures in the highest risk patients, and the appearance of a significant number of new antibiotics in recent years (some very specifically directed against certain mechanisms of resistance and others with a broader spectrum of applications) have led us to shift our questions from "what to deal with" to "how to treat". There has been controversy about how best to approach antibiotic treatment of complex cases of sepsis. The individualized and adjusted dosage, the moment of its administration, the objective, and the selection of the regimen are pointed out as factors of special relevance in a critically ill patient where the frequency of resistant microorganisms, especially among the Enterobacterales group, and the emergence of multiple and diverse antibiotic treatment alternatives have made the appropriate choice of antibiotic treatment more complex, requiring a constant updating of knowledge and the creation of multidisciplinary teams to confront new infections that are difficult to treat. In this article, we have reviewed the phenomenon of the emergence of resistance to antibacterials and we have tried to share some of the ideas, such as stewardship, sparing carbapenems, and organizational, microbiological, pharmacological, and knowledge tools, that we have considered most useful and effective for individualized decision making that takes into account the current context of multidrug resistance. The greatest challenge, therefore, of decision making in this context lies in determining an effective, optimal, and balanced empirical antibiotic treatment.

Bring it on again: antimicrobial stewardship in transplant infectious diseases: updates and new challenges

Advancement in solid organ transplantation and hematopoietic stem cell transplant continues to improve the health outcomes of patients and widens the number of eligible patients who can benefit from the medical progress. Preserving the effectiveness of antimicrobials remains crucial, as otherwise transplant surgeries would be unsafe due to surgical site infections, and the risk of sepsis with neutropenia would preclude stem cell transplant. In this review, we provide updates on three previously discussed stewardship challenges: febrile neutropenia, Clostridioides difficile infection, and asymptomatic bacteriuria. We also offer insight into four new stewardship challenges: the applicability of the "shorter is better" paradigm shift to antimicrobial duration; antibiotic allergy delabeling and desensitization; colonization with multidrug-resistant gram-negative organisms; and management of cytomegalovirus infections. Specifically, data are accumulating for "shorter is better" and antibiotic allergy delabeling in transplant patients, following successes in the general population. Unique to transplant patients are the impact of multidrug-resistant organism colonization on clinical decision-making of antibiotic prophylaxis in transplant procedure and the need for antiviral stewardship in cytomegalovirus. We highlighted the expansion of antimicrobial stewardship interventions as potential solutions for these challenges, as well as gaps in knowledge and opportunities for further research.

Oral amoxicillin challenges for low-risk penicillin-allergic patients at a large Veterans Affairs facility: a retrospective feasibility analysis

We retrospectively reviewed the records of 136 veterans with a penicillin allergy label during a quality improvement initiative. We identified 82 inpatients eligible for removal of penicillin allergy by oral amoxicillin challenge, including 40 out of 82 (48%) still eligible after accounting for other limiting factors.

Postoperative infections after sinus lifts and onlay grafts in penicillin allergic patients

INTRODUCTION

The primary objective of this retrospective study was to determine whether patients treated with clindamycin due to a reported allergy to penicillin have an increased risk of postsurgical infections after sinus lifts and onlay grafts.

MATERIAL AND METHODS

A retrospective cohort study was performed on patients who underwent bone reconstruction procedures between October 2018 and December 2020. Data from all patients operated at the Pitié Salpêtrière University Hospital for sinus lifts or onlay grafts were collected. All surgical procedures studied were performed under preoperative and postoperative antibiotic prophylaxis with either amoxicillin (+/- clavulanic acid) or clindamycin for patients with reported penicillin allergy. Bone graft-associated infections as well as graft failures were recorded.

RESULTS

In this study, 111 patients received bone reconstructions (89 sinus lifts and 148 onlay grafts). In the sinus lifts group, infections occurred in 5 of 89 sites (5.6 %). The infection rate was 28.5 % (7 graft sites) and only 3.9 % (82 graft sites) for clindamycin and for amoxicillin, respectively. In the onlay graft group, infections occurred in 25 of 148 sites (16.8 %). The infection rate was 56 % and only 12 % for clindamycin (18 graft sites) and for amoxicillin, respectively (130 graft sites). Non-Penicillin treated patients had a higher risk of infection with an odd ratio of 7.8 (95 % CI 1.1-54.8, P = 0.04) and 4.8 (95 % CI 1.9-12.3, P = 0.001) compared with patients receiving amoxicillin for onlay grafts and sinus lifts.

CONCLUSION

Penicillin allergy and clindamycin use after sinus lift and onlay graft procedures were associated with a higher rate of infection and may be a risk factor for complications related to bone reconstruction surgery.

The role of clinical pharmacists in patients with suspected allergy to β-lactams: A systematic review

OBJECTIVE

To analyze the role played by the clinical pharmacist and its impact in antibiotic stewardship facing suspected allergy to beta-lactam antibiotics.

METHOD

We performed two different independent bibliographic searches. A total of 35 articles were found, and the final number included in the study was 12. We analysed the articles and collected variables of efficacy, safety and applicability of evaluation tools applied to patients with suspected allergy to beta-lactams. Also, the variation in the consumption and prescription profile of alternative antibiotics was analyzed.

RESULTS

The selected studies analysed questionnaires, allergy delabeling, intradermal tests and oral challenge tests performed by pharmacists. Significant differences in the efficacy endpoint were found in 4 studies in favour of pharmaceutical intervention. In the study of Kwiatkowski et al, cefazolin use increased in surgical patients after pharmacist intervention (65 vs. 28%; p < 0.01). In a quasi-experimental study, the mean defined daily dose of aztreonam and the mean days of therapy per 1000 patients/day decreased (21.23 vs 9.05, p <0.01) and (8.79-4.24, p = 0.016), pre and post-intervention, respectively, increasing antibiotic de-escalations (p ≤ 0.01). In another quasi-experimental study, the prescription of restricted-use antibiotics decreased (42.5% vs. 17.9%, p < 0.01) and the use of pre-surgical prophylactic antibiotics alternative to cefazolin (81.9% vs 55.9%, p<0.01) in another study. Other study showed that the mean time per interview was 5.2 minutes per patient. No adverse events were reported in any study.

CONCLUSION

The pharmacist intervention in the evaluation of the patient with suspected allergy to beta-lactams is effective, safe and feasible to implement on daily clinical practice. The standardization of protocols to clarify the history of allergies and development of evaluation tools represent simple screenings to perform delabelling or refer to the Immunoallergology service, improving penicilins use and reducing the need for second line antibiotics. More studies are needed to standardize the desensitization tests made by pharmacists. However, despite these results, the involvement and leadership of the pharmacist in this area is limited and constitutes a future challenge for the profession.

Low-risk penicillin allergy delabeling: a scoping review of direct oral challenge practice, implementation, and multi-disciplinary approaches

INTRODUCTION

Penicillin allergy is common, and there is increased clinician interest in direct oral challenge (DOC) as a testing strategy for low-risk penicillin allergy. To aid wider implementation of DOC, consensus definitions of low-risk penicillin allergy phenotypes, and standardized approaches to assessment, DOC procedures, and evaluation, are required.

AREAS COVERED

This review systematically reviews studies that have utilized penicillin DOC in healthcare settings to identify heterogeneity in implementation approaches and synthesize low-risk definitions, procedures, and evaluation.

EXPERT OPINION

Opportunity exists to standardize penicillin DOC procedures in patients with a low-risk penicillin allergy to optimize antimicrobial prescribing and reduce the burden of penicillin allergy. Standardizing the definitions of 'low-risk' and 'positive challenge,' and improving the evaluation of patient safety, alongside the development of a unified approach to the structure of undertaking an oral challenge, is likely to increase uptake and confidence among non-allergist clinicians.

[Translated article] The role of clinical pharmacists in patients with suspected allergy to β-lactams: A systematic review

OBJECTIVE

To analyze the role played by the clinical pharmacist and its impact in antibiotic stewardship facing suspected allergy to beta-lactam antibiotics.

METHOD

We performed 2 different independent bibliographic searches. A total of 35 articles were found, and the final number included in the study was 12. We analyzed the articles and collected variables of efficacy, safety, and applicability of evaluation tools applied to patients with suspected allergy to beta-lactams. Also, the variation in the consumption and prescription profile of alternative antibiotics was analyzed.

RESULTS

The selected studies analyzed questionnaires, allergy delabeling, intradermal tests, and oral challenge tests performed by pharmacists. Significant differences in the efficacy endpoint were found in 4 studies in favor of pharmaceutical intervention. In the study of Kwiatkowski et al., cefazolin use increased in surgical patients after pharmacist intervention (65% vs 28%; P < .01). In a quasi-experimental study, the mean defined daily dose of aztreonam and the mean days of therapy per 1000 patients/day decreased (21.23 vs 9.05, P <.01) and (8.79-4.24, P = .016), pre- and post-intervention, respectively, increasing antibiotic de-escalations (P = < .01). In another quasi-experimental study, the prescription of restricted use antibiotics decreased (42.5% vs 17.9%, P < .01)and the use of pre-surgical prophylactic antibiotics alternative to cefazolin (81.9% vs 55.9%, P < .01)in another study. Other study showed that the mean time per interview was 5.2 min per patient. No adverse events were reported in any study.

CONCLUSION

The pharmacist intervention in the evaluation of the patient with suspected allergy to beta-lactams is effective, safe, and feasible to implement on daily clinical practice. The standardization of protocols to clarify the history of allergies and development of evaluation tools represent simple screenings to perform delabeling or refer to the Immunoallergology service, improving penicilins use and reducing the need for second-line antibiotics. More studies are needed to standardize the desensitization tests made by pharmacists. However, despite these results, the involvement and leadership of the pharmacist in this area is limited and constitutes a future challenge for the profession.

Antibiotic prophylaxis in immunosuppressed patients - Missed opportunities from trimethoprim-sulfamethoxazole allergy label

Trimethoprim-sulfamethoxazole (TMP-SMX) is a broad spectrum antibiotic in use for more than 50 years. It has an important indication as first line agent in the prophylaxis of opportunistic infections, particularly Pneumocystis jirovecii pneumonia (PJP), in immunosuppressed patients. For those who have a history of allergy or severe intolerance to TMP-SMX, pentamidine, dapsone or atovaquone may be substituted; however there is evidence that TMP-SMX offers superior coverage for PJP, toxoplasmosis, and nocardiosis. Compared to pentamidine, it has the added benefit of cost-effectiveness and self-administration as opposed to required hospital attendance for administration. Many patients who report a history of allergy or adverse reaction to TMP-SMX (or "sulfur allergy") will be found not to be allergic; and even those who are allergic may be able to be desensitized. The evaluation and, where appropriate, removal of TMP-SMX allergy label enables the use of TMP-SMX for prophylaxis against opportunistic infections. This is a cost-effective intervention to optimize antimicrobial prescribing and reduce the risk of opportunistic infections in immunosuppressed patients.

Including hemoglobin levels and female sex provide the additional predictive value of the APPLE score for atrial fibrillation recurrence post-catheter ablation

OBJECTIVE

We probed whether the addition of hemoglobin (HGB) or the female sex (SEX) as variables would provide additional prognostic value to the APPLE score.

METHODS

An optimized APPLE score was used to evaluate the AF recurrence risk in the consecutive populations with AF post-catheter ablation including the development (n = 562) and validation (n = 239) cohorts.

RESULTS

In the populations of AF recurrence, most patients were female sex (103/164, 62.8%), and had the lower HGB levels. After adjusting for the APPLE score, HGB level (Odds Ratio [OR], 0.828; 95% Confidence Interval [CI], 0.749-0.915; P < 0.001) and female sex (OR, 1.596; 95% CI, 1.140-2.235; P = 0.006) independently predicted AF recurrence. Adjusting the APPLE score by HGB variable improved its predictive ability for AF recurrence (C-statistic value from 0.675 to 0.711, P = 0.010), which also increased the C-indexes in the external validation (from 0.653 to 0.725, p = 0.023). The female sex variable also enhanced the C-statistic value of the APPLE score for AF recurrence at both development and external validation (C-indices from 0.675 to 0.691, P = 0.004; C-indices from 0.653 to 0.704, p = 0.037, respectively). Decision curve analysis showed that the HGB plus APPLE score was better than the SEX plus APPLE score in predicting AF recurrence in two following AF populations.

CONCLUSION

The inclusion of HGB level and female sex variables improved the predictability and clinical usefulness of adjusted APPLE score. Adjustment of the APPLE score by HGB levels may provide better predictive value than inclusion of the female sex variable.

Ethics of antibiotic allergy

Antibiotic allergies are commonly reported among patients, but most do not experience reactions on rechallenge with the same agents. These reported allergies complicate management of infections in patients labelled as having penicillin allergy, including serious infections where penicillin-based antibiotics are the first-line (most effective and least toxic) treatment option. Allergy labels are rarely questioned in clinical practice, with many clinicians opting for inferior second-line antibiotics to avoid a perceived risk of allergy. Reported allergies thereby can have significant impacts on patients and public health, and present major ethical challenges. Antibiotic allergy testing has been described as a strategy to circumvent this dilemma, but it carries limitations that often make it less feasible in patients with acute infections or in community settings that lack access to allergy testing. This article provides an empirically informed ethical analysis of key considerations in this clinical dilemma, using Staphylococcus aureus bacteraemia in patients with penicillin allergies as a case study. We argue that prescribing first-line penicillin-based antibiotics to patients with reported allergies may often present a more favourable ratio of benefits to risks, and may therefore be more ethically appropriate than using second-line drugs. We recommend changes to policy-making, clinical research and medical education, in order to promote more ethically acceptable responses to antibiotic allergies than the status quo.

Prevalence of reported penicillin allergy and associations with perioperative complications, length of stay, and cost in patients undergoing elective cancer surgery

Objective

Up to 10% of patients report penicillin allergy (PA), although only 1% are truly affected by Ig-E-mediated allergies. PA has been associated with worse postoperative outcomes, but studies on the impact of reported PA in cancer patients are lacking, and especially in these multimorbid patients, a non-complicated course is of utmost importance.

Methods

Retrospective analysis of patients undergoing elective oncological surgery at a tertiary reference center. Data on surgical site infections (SSI), postoperative complications (measured by Clavien-Dindo classification and Comprehensive Complication Index (CCI)), hospitalization duration, and treatment costs were collected.

Results

Between 09/2019 and 03/2020, 152 patients were identified. 16/152 patients (11%) reported PA, while 136/152 (89%) did not. There were no differences in age, BMI, Charlson Comorbidity Index, and smoking status between groups (p > 0.4). Perioperative beta-lactam antibiotics were used in 122 (89.7%) and 15 (93.8%) patients without and with reported PA, respectively. SSI and mean numbers of infections occurred non-significantly more often in patients with PA (p = 0.2 and p = 0.47). The median CCI was significantly higher in PA group (26 vs. 51; p = 0.035). The median hospitalization duration and treatment costs were similar between non-PA and PA groups (4 vs 3 days, p = 0.8; 16'818 vs 17'444 CHF, p = 0.4).

Conclusions

In patients undergoing cancer surgery, reported PA is common. Failure to question the unproven PA may impair perioperative outcomes. For this reason, patient and provider education on which reactions constitute a true allergy would also assist in allergy de-labeling. In addition, skin testing and oral antibiotic challenges can be performed to identify the safe antibiotics and to de-label appropriate patients.

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.

Penicillin allergy de-labelling by non-allergists: a comparison of testing protocols

Optimizing penicillin allergy de-labelling (PADL) to ensure patients with an incorrect penicillin allergy record are de-labelled with minimal patient harm is important for antibiotic stewardship. The heterogeneity of inclusion and exclusion criteria in the published penicillin allergy testing protocols risks suboptimal delivery of PADL. We compared the similarities and the differences between non-allergist-delivered PADL testing protocols and make suggestions for harmonization. The observed variation in testing practice has two broad elements: (i) definitions and terminology; and (ii) differences in the acceptability of perceived risk. All direct drug provocation testing (DDPT) protocols included patients with benign delayed rash as eligible for testing, although the remoteness of the rash, and the terminology used to describe the rash, differed. Patients with features of potential IgE reactions were excluded from most DDPT protocols, but not all of them. There was differing advice on how to manage patients who had subsequently tolerated penicillin since the index reaction and differences in which patients were considered ineligible for DDPT due to acuity of illness, comorbidities and concomitant medications. Standardization of the terminology used in penicillin allergy testing protocols and consensus on inclusion and exclusion criteria are required for safe and efficient PADL delivery at scale by non-allergists.

Describing Self-Reported Penicillin Allergy Using a Penicillin Allergy Risk Tool (PEN-FAST) in an Outpatient Setting at a Tertiary Hospital in Saudi Arabia

Introduction Penicillin is a widely used antibiotic and is frequently reported as a cause of allergic reactions. However, many individuals reporting penicillin allergies are later found to be tolerant. This study, conducted in an outpatient setting at King Abdulaziz University Hospital (KAUH) in Jeddah, Saudi Arabia, aimed to assess the prevalence of self-reported penicillin allergy and to evaluate further the risk of a positive penicillin allergy test using the PEN-FAST tool. Methods A cross-sectional study was conducted via in-person questionnaires with patients in the waiting area at the outpatient clinics of KAUH in Jeddah, Saudi Arabia. Results Among 140 participants, 4% reported a penicillin allergy, with most identifying their allergies based on symptoms. None of these allergies resulted in severe reactions. Notably, 50% reported nausea and itching as symptoms. The PEN-FAST tool categorized 33.3% as moderate risk and 50% as low to very low risk for a positive penicillin skin test. One participant was confirmed to be allergic via a skin prick test. Discussion and conclusion The prevalence of reported penicillin allergy was lower in our study than that previously reported. Evaluation of the PEN-FAST score demonstrated that this prevalence is even lower at 2%. While this single-center study offers valuable insights, further research in diverse healthcare settings is required to validate these findings and refine our understanding of penicillin allergies.

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.

Approach for delabeling beta-lactam allergy in children

A considerable number of pediatric patients treated with beta-lactam (BL) antibiotics develop delayed onset of skin rashes during the course of treatment. Although the most frequent cause of these symptoms is infectious, many cases are labeled as allergic reactions to these drugs. BL allergy labels could have a negative impact, as they imply avoidance of this group of drugs and the use of second-line antibiotics, leading to a potential increase in adverse effects and the utilization of less effective therapies. This constitutes a major public health concern and economic burden, as the use of broad-spectrum antibiotics can result in multidrug-resistant organisms and prolonged hospital stays. Therefore, it is crucial to delabel patients during childhood to avoid false labeling in adult life. Although the label of BL allergy is among the most frequent causes of allergy referral, its management remains controversial, and new diagnostic perspectives are changing the paradigm of managing BL allergies in children. Traditionally, drug provocation testing (DPT) was exclusively performed in patients who had previously obtained negative results from skin tests (STs). However, the sensitivity of STs is low, and the role of in vitro testing in the pediatric population is not well defined. Recent studies have demonstrated the safety of direct DPT without prior ST or serum tests for pediatric patients who report a low-risk reaction to BLs, which is cost-effective. However, there is still a debate on the optimal allergic workup to be performed in children with a benign immediate reaction and the management of children with severe cutaneous adverse drug reactions. In this review, we will discuss the impact of the label of BL allergy and the role of the different tools currently available to efficiently address BL allergy delabeling in children.

Assessing delayed penicillin hypersensitivity using the PENFAST+ score

Introduction

Approximately 10% of individuals report a suspected allergy to penicillin, but according to allergy work-ups, only 10%-15% of them are truly allergic. A clinical decision score, the PEN-FAST, was developed and validated to identify adults with low-risk penicillin allergy.

Objectives

The objective of this study was to improve the performance of the PEN-FAST score, particularly for those with delayed hypersensitivity (HS), by improving the negative predictive value.

Methods

STEP 1: Retrospective evaluation of the PEN-FAST score in patients with proven immediate and delayed penicillin allergy. STEP 2: Identification of additional criteria among Step 1 patients misclassified by PEN-FAST score. Development of the PEN-FAST+ score using multivariable logistic regression in a prospective cohort of patients with a suspicion of HS to penicillin. STEP 3: Comparison of diagnostic performances of PEN-FAST and PEN-FAST+ scores.

Results

The PEN-FAST score showed limitations in predicting the relapse of immediate skin HS or delayed maculopapular exanthema, with 28.6% and 38.4% of patients misclassified, respectively. We identified two potential additional criteria: skin rash lasting more than 7 days and immediate reaction occurring in less than 1 h (generalized or localized on palmoplantar area or scalp itching/heat feeling). A total of 32/252 (12.7%) patients were confirmed to be allergic to penicillin. With PEN-FAST, 37% of patients (n = 10) with delayed allergic penicillin HS were misclassified. With PEN-FAST+, 3 patients with delayed HS confirmed by a ST (11.1%) were misclassified. The AUC was significantly higher for PEN-FAST+ than PEN-FAST (85% vs. 72%, p = 0.03).

A new clinical opportunity: Rechallenging penicillin allergy in an outpatient pharmacy

In the United States, approximately 27 million people have a documented penicillin allergy, but 90% of the allergies are falsely labeled. By rechallenging suspected allergies, a pharmacist can optimize patient care, fulfill antimicrobial stewardship objectives, and educate patients on true allergies. We suggest a protocol that allows pharmacists to investigate the presence of an allergy and conduct a challenge when indicated. The protocol consists of a patient interview, a risk assessment, an oral rechallenge, and the potential for a skin test. The testing and delabeling of penicillin allergies will enhance the practice of antimicrobial stewardship in the outpatient setting. In the changing landscape of pharmacy, community pharmacists can increase their services and improve patient care. Owing to limited documented experience in the outpatient pharmacy, an opportunity to set the standard and be a leader in the field is present.

Drug allergy in older adults: A study from the United States Drug Allergy Registry

BACKGROUND

Older adults have an increased risk of adverse drug reactions and negative effects associated with alternative antibiotic use. Although the number of antibiotic allergies reported increases with age, the characteristics and outcomes of older adults receiving drug allergy assessment are unknown.

OBJECTIVE

To assess the characteristics and outcomes of drug allergy evaluations in older adults.

METHODS

We considered patients aged above or equal to 65 years enrolled in the United States Drug Allergy Registry (USDAR), a US multisite prospective cohort (January 16, 2019 to February 28, 2022). Data were summarized using descriptive statistics.

RESULTS

Of 1678 USDAR participants from 5 sites, 406 older adults aged above or equal to 65 years (37% 65-69 years, 37% 70-74 years, 16% 75-79 years, and 10% ≥80 years) received 501 drug allergy assessments. USDAR older adults were primarily of female sex (69%), White (94%), and non-Hispanic (98%). Most USDAR older adults reported less than or equal to 1 infections per year (64%) and rated their general health as good, very good, or excellent (80%). Of 296 (59%) penicillin allergy assessments in USDAR older adults, 286 (97%) were disproved. Other drug allergy assessments included sulfonamide (n = 41, 88% disproved) and cephalosporin (n = 20, 95% disproved) antibiotics. All 41 drug allergy labels in USDAR participants aged above or equal to 80 years and all 80 penicillin allergy labels in USDAR men aged above or equal to 65 years were disproved.

CONCLUSION

Older adults represented a quarter of USDAR participants but were neither racially nor ethnically diverse and were generally healthy without considerable antibiotic need. Most older adults presented for antibiotic allergy assessments, the vast majority of which were disproved. Drug allergy assessments may be underutilized in the older adults who are most vulnerable to the harms of unconfirmed antibiotic allergy labels.

Qualitative analysis of healthcare provider perspectives to evaluating beta-lactam allergies

BACKGROUND

There is a lack of understanding of the barriers reported by healthcare providers when evaluating beta-lactam allergies, but knowledge of these barriers is required for practical and effective implementation interventions.

METHODS

Twenty-five healthcare providers, consisting of physicians, nurses and pharmacists practicing in the areas of intensive care, emergency medicine, infectious disease and general hospital practice, were interviewed between September 2021 and July 2023. Twenty-three of these providers were practising in the USA. A semi-structured interview guide grounded in the Theoretical Domain Framework was used for the interviews. Deductive and inductive analysis was performed on the interview transcripts, and translated into intervention recommendations using the Behaviour Change Wheel.

RESULTS

Widely held beliefs included a lack of clear policy for the evaluation of allergies, confusing or missing documentation of allergy information, confidence in their own and their colleagues' ability to evaluate allergies when information is available, and pharmacists as the provider most equipped to evaluate beta-lactam allergies.

CONCLUSIONS

Health systems should adopt and disseminate policies for the evaluation of beta-lactam allergies, and promote the use of pharmacists in the evaluation of drug allergies when possible. Allergy sections of electronic health records should be reworked to encourage unambiguous documentation of allergy reactions and support using previously tolerated beta-lactam antibiotics.

Direct challenges are the gold standard for most antibiotic allergy evaluations

Antibiotic allergies are frequently encountered in clinical practice, and delabeling of these allergies has individual and public health benefits. This review focuses on the evidence supporting graded challenges without preceding skin testing in adult and pediatric patients to the major groups of antibiotics including penicillins, cephalosporins, sulfamethoxazole, fluoroquinolones, tetracyclines, macrolides, metronidazole, carbapenems, and aztreonam. The cost savings, time savings, and evidence for performing graded challenges outside of an allergy/immunology office are also reviewed for graded challenges to penicillins.

Analysis of a beta-lactam allergy assessment protocol challenging diverse reported allergies managed by an antimicrobial stewardship program

Objective

To assess the safety and efficacy of a novel beta-lactam allergy assessment algorithm managed by an antimicrobial stewardship program (ASP) team.

Design

Retrospective analysis.

Setting

One quaternary referral teaching hospital and one tertiary care teaching hospital in a large western Pennsylvania health network.

Patients or participants

Patients who received a beta-lactam challenge dose under the beta-lactam allergy assessment algorithm.

Interventions

A beta-lactam allergy assessment protocol was designed and implemented by an ASP team. The protocol risk stratified patients' reported allergies to identify patients appropriate for a challenge with a beta-lactam antibiotic. This retrospective analysis assessed the safety and efficacy of this protocol among patients receiving a challenge dose from November 2017 to July 2021.

Results

Over a 45-month period, 119 total patients with either penicillin or cephalosporin allergies entered the protocol. Following a challenge dose, 106 (89.1%) patients were treated with a beta-lactam. Eleven patients had adverse reactions to a challenge dose, one of which required escalation of care to the intensive care unit. Of the patients with an unknown or low-risk reported allergy, 7/66 (10.6%) had an observed adverse reaction compared to 3/42 (7.1%) who had an observed reaction with a reported high-risk or anaphylactic allergy.

Conclusions

Our implemented protocol was safe and effective, with over 90% of patients tolerating the challenge without incident and many going on to receive indicated beta-lactam therapy. This protocol may serve as a framework for other inpatient ASP teams to implement a low-barrier allergy assessment led by ASP teams.

Efficacy of a Clinical Decision Rule to Enable Direct Oral Challenge in Patients With Low-Risk Penicillin Allergy: The PALACE Randomized Clinical Trial

Importance

Fewer than 5% of patients labeled with a penicillin allergy are truly allergic. The standard of care to remove the penicillin allergy label in adults is specialized testing involving prick and intradermal skin testing followed by an oral challenge with penicillin. Skin testing is resource intensive, limits practice to specialist-trained physicians, and restricts the global population who could undergo penicillin allergy delabeling.

Objective

To determine whether a direct oral penicillin challenge is noninferior to the standard of care of penicillin skin testing followed by an oral challenge in patients with a low-risk penicillin allergy.

Design, Setting, and Participants

This parallel, 2-arm, noninferiority, open-label, multicenter, international randomized clinical trial occurred in 6 specialized centers, 3 in North America (US and Canada) and 3 in Australia, from June 18, 2021, to December 2, 2022. Eligible adults had a PEN-FAST score lower than 3. PEN-FAST is a prospectively derived and internationally validated clinical decision rule that enables point-of-care risk assessment for adults reporting penicillin allergies.

Interventions

Patients were randomly assigned to either direct oral challenge with penicillin (intervention arm) or a standard-of-care arm of penicillin skin testing followed by oral challenge with penicillin (control arm).

Main Outcome and Measure

The primary outcome was a physician-verified positive immune-mediated oral penicillin challenge within 1 hour postintervention in the intention-to-treat population. Noninferiority was achieved if a 1-sided 95% CI of the risk difference (RD) did not exceed 5 percentage points (pp).

Results

A total of 382 adults were randomized, with 377 patients (median [IQR] age, 51 [35-65] years; 247 [65.5%] female) included in the analysis: 187 in the intervention group and 190 in the control group. Most patients had a PEN-FAST score of 0 or 1. The primary outcome occurred in 1 patient (0.5%) in the intervention group and 1 patient (0.5%) in the control group, with an RD of 0.0084 pp (90% CI, -1.22 to 1.24 pp). The 1-sided 95% CI was below the noninferiority margin of 5 pp. In the 5 days following the oral penicillin challenge, 9 immune-mediated adverse events were recorded in the intervention group and 10 in the control group (RD, -0.45 pp; 95% CI, -4.87 to 3.96 pp). No serious adverse events occurred.

Conclusions and Relevance

In this randomized clinical trial, direct oral penicillin challenge in patients with a low-risk penicillin allergy was noninferior compared with standard-of-care skin testing followed by oral challenge. In patients with a low-risk history, direct oral penicillin challenge is a safe procedure to facilitate the removal of a penicillin allergy label.

Trial Registration

ClinicalTrials.gov Identifier: NCT04454229.

Genetic association of beta-lactams-induced hypersensitivity reactions: A systematic review of genome-wide evidence and meta-analysis of candidate genes

Importance

Beta-lactams (BLs) are the most prescribed antibiotics, being the most frequent cause of drug allergy. However, the association between BL allergy and genetic variations is still unclear.

Objective

This systematic review and meta-analysis aimed to summarize the genetic effects of BL-induced hypersensitivity using existing evidence.

Methods

We searched PubMed, Medline, Scopus, EMBASE, CINAHL, and Cochrane Library from inception to September 15, 2022 with no language restriction. Genetic association studies investigating genetic variant/polymorphism and risk of drug-induced hypersensitivity reactions among individuals receiving BL-antibiotics were included. We excluded studies of acute interstitial nephritis, drug-induced liver injury, serum sickness, and isolated drug fever. Data were comprehensively synthesized and quality of study were assessed using STrengthening the Reporting of Genetic Association Studies (STREGA). The record screening, extraction and quality assessment were performed by two reviewers and discussions were made to resolve discrepancies. The effects of each variant were pooled and evaluated by modified Venice criteria.

Results

A total of 9276 records were identified, and 31 studies were eligible for inclusion. Twenty-seven were candidate-gene association studies (5416 cases and 5939 controls), while the others were next-generation sequencing (NGS) or genome-wide association studies (GWASs) (119 838 cases and 1 487 111 controls). Forty-nine polymorphisms were identified and most of them located in allergic reaction pathways. Meta-analyses of 15 candidate variants in a mixture of both immediate and non-immediate reactions revealed weak genetic effects of rs1801275 (8 studies; n = 1,560; odd ratio 0.73; 95%CI: 0.57-0.93) and rs20541 (4 studies; n = 1,482; odd ratio 1.34; 95%CI: 1.07-1.68) in IL4R and IL13, respectively. Results from GWASs and NGS identified, and confirmed associations in HLA regions including HLA-DRA, HLA-B, HLA-DQA, HLA-DRB1, and HLA-DRB3.

Conclusion

Our study summarized genetic evidence influencing BL-induced hypersensitivity and estimated effects of potential variants. We postulated that the genomic studies provide better insights to the mechanism of reactions and suggest potential effects of HLA Class II variants. However, results were inconsistent and unable to generalize in different settings. Further high-throughput studies with a well-defined function, epigenetic interaction, incorporated with clinical factors, would be beneficial for risk identification in BL-induced hypersensitivity.

[Antibiotic treatment of community-acquired and hospital-acquired pneumonia]

Community-acquired and nosocomial bacterial pneumonia are among the most common infectious diseases in Germany. Knowledge of possible pathogens and therapeutic implications thereof are essential to be able to provide adequate, differentiated antimicrobial therapy with the appropriate drugs, form of application, dose, and duration. New diagnostics that include multiplex polymerase chain reaction, correct interpretation of the biomarker procalcitonin, and treatment of multidrug-resistant bacteria are becoming increasingly import.

Improving the Documentation of Penicillin Allergy Labels Among Pediatric Inpatients

BACKGROUND AND OBJECTIVES

Penicillin allergy is the most common medication allergy, and the penicillin allergy label is commonly over-applied without adequate reaction history inquiry or documentation. Because penicillin allergy labels are often applied in childhood and carried into adulthood, we sought to increase the completeness of reaction history documentation from 20% to 70% for pediatric hospital medicine patients and from 20% to 50% for all other pediatric inpatients within 12 months. As a secondary outcome, we also aimed to increase the proportion of delabeling unnecessary penicillin labels to 20% for all pediatric inpatients.

METHODS

To address our aims, our quality improvement initiative included education for pediatric faculty and staff, development and implementation of a clinical pathway for allergy risk stratification, and electronic health record optimizations. Statistical process control charts were used to track the impact of the interventions facilitated by an automated dashboard.

RESULTS

Within 12 months of interventions, the completeness of allergy labels improved from 20% to 64% among patients admitted to the pediatric hospital medicine service and improved from 20% to 45% for all other pediatric inpatients. The frequency of penicillin allergy delabeling remained unchanged; however, 98 patients were risk stratified and 34 received outpatient allergy referrals for further testing. The number of adverse drug reactions to penicillin, a balancing measure, did not change during the study period.

CONCLUSIONS

We increased the completeness of penicillin allergy documentation using a standardized workflow facilitated by a multidisciplinary clinical pathway. With ongoing efforts, more penicillin delabeling in low-risk patients is anticipated.

Evaluating the PEN-FAST Clinical Decision-making Tool to Enhance Penicillin Allergy Delabeling

This cohort study evaluated the diagnostic accuracy of PEN-FAST as a clinical decision-making tool to enhance penicillin allergy evaluation.

Perceived usefulness of a mnemonic to improve nurses' evaluation of reported penicillin allergies

We surveyed clinicians to evaluate the perceived usefulness of a mnemonic, STORY, to improve penicillin allergy evaluation. Survey responses indicated that the perceived usefulness of STORY was high, and support for nurses' involvement in penicillin allergy assessment was high. Future research may evaluate the feasibility of STORY implementation in clinical care.

Characterizing Antibiotic Allergy Labels in a Large UK Hospital Population to Inform Antimicrobial Stewardship and Delabeling Assessment Strategy

BACKGROUND

Antibiotic allergy labels are important barriers to treatment and antimicrobial stewardship, but their prevalence in UK hospitals is poorly described.

OBJECTIVE

To ascertain the prevalence and characteristics of antibiotic allergy labels in a large UK hospital setting and estimate the proportion of penicillin allergy labels for which point-of-care (POC) delabeling assessment would be appropriate.

METHODS

Electronic health records data were analyzed from all patients treated at Cambridge University Hospitals NHS Foundation Trust in 2019. Validated POC delabeling risk stratification criteria were retrospectively applied to penicillin allergy labels.

RESULTS

Recorded reactions to antibiotics were present in 11.8% of all patients (32,148 of 273,216), 16.3% of inpatients (13,874 of 85,230), and 9.7% of outpatients (18,274 of 187,986). Penicillins were the commonest reaction precipitant described (9.0% of patients; 24,646 of 273,216), followed by sulfonamides/trimethoprim (1.4%; 3869 of 273,216) and macrolides/lincosamides (1.3%; 3644 of 273,216). A total of 3.9% of inpatients had recorded reactions to >1 antibiotic class (3348 of 85,230). Cutaneous manifestations were the most commonly described reaction features (40.7% of labels; 15,821 of 38,902). Of 15,949 labels describing probable or possible penicillin "allergy" with sufficient detail to allow for the retrospective assessment of POC delabeling suitability, 1702 were deemed suitable for removal or downgrading of the label to "intolerance" without further investigation (10.7%), 11,887 were appropriate for POC assessment using an oral penicillin challenge (OPC) or OPC with prior bedside skin testing (74.5%), and 2360 were identified as unsuitable for any form of POC assessment (14.8%).

CONCLUSIONS

Antibiotic allergy labels are highly prevalent in a UK hospital setting. A large proportion of penicillin allergy labels may be suitable for POC delabeling assessment.