The incidence of antimicrobial allergies in hospitalized patients: implications regarding prescribing patterns and emerging bacterial resistance

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.

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.

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.

The Application of Knowledge-Based Clinical Decision Support Systems to Detect Antibiotic Allergy

Prevention of drug allergies is important for patient safety. The objective of this study was to evaluate the outcomes of antibiotic allergy-checking clinical decision support system (CDSS), K-CDSTM. A retrospective chart review study was performed in 29 hospitals and antibiotic allergy alerts data were collected from May to August 2022. A total of 15,535 allergy alert cases from 1586 patients were reviewed. The most frequently prescribed antibiotics were cephalosporins (48.5%), and there were more alerts of potential cross-reactivity between beta-lactam antibiotics than between antibiotics with the same ingredients or of the same class. Regarding allergy symptoms, dermatological disorders were the most common (38.8%), followed by gastrointestinal disorders (28.4%). The 714 cases (4.5%) of immune system disorders included 222 cases of anaphylaxis and 61 cases of severe cutaneous adverse reactions. Alerts for severe symptoms were reported in 6.4% of all cases. This study confirmed that K-CDS can effectively detect antibiotic allergies and prevent the prescription of potentially allergy-causing antibiotics among patients with a history of antibiotic allergies. If K-CDS is expanded to medical institutions nationwide in the future, it can prevent an increase in allergy recurrence related to drug prescriptions through cloud-based allergy detection CDSSs.

Introduction of a penicillin allergy de-labelling program with direct oral challenge and its effects on utilization of beta-lactam antimicrobials: a multicenter retrospective parallel cohort study

BACKGROUND

Self-reported penicillin allergy labels are common and often inaccurate after assessment. These labels can lead to reduced use of first-line beta-lactam antibiotics and worse outcomes. We measured the impact of a previously performed inpatient proactive systematic penicillin allergy de-labelling program on subsequent antibiotic use. This prior program included assessment, risk-stratification, and low risk direct oral amoxicillin challenge.

METHODS

We performed a retrospective comparison of parallel cohorts from two separate tertiary care hospital campuses in Ottawa, Canada across two penicillin de-labelling intervention periods across April 15th to April 30th, 2021, and February 15th to March 8th, 2022. Outcomes, including penicillin allergy labelling and antibiotic use, were collected for the index admission and the subsequent 6-month period. Descriptive statistics and multivariate regression analyses were performed.

RESULTS

A total of 368 patients with penicillin allergy label were included across two campuses and study periods. 24 (13.8%) patients in the intervention groups had sustained penicillin allergy label removal at 30 days from admission vs. 3 (1.5%) in the non-intervention group (p < 0.001). In the 6-months following admission, beta-lactams were prescribed more frequently in the intervention groups vs. the non-intervention groups for all patients (28 [16.1%] vs.15 [7.7%], p = 0.04) and were prescribed more frequently amongst those who received at least one antibiotic (28/46 [60.9%] vs.15/40 [37.5%], p = 0.097). In a multivariate regression analysis, the intervention groups were found to be associated with an increased odds of beta-lactam prescribing in all patients (OR 2.49, 95%CI 1.29-5.02) and in those prescribed at least one antibiotic (OR 2.44, 95%CI 1.00-6.15). No drug-related adverse events were reported.

CONCLUSIONS

Proactive penicillin allergy de-labelling for inpatients was associated with a reduction in penicillin allergy labels and increased utilization of beta-lactams in the subsequent 6-months.

Safety of direct oral provocation test to delabel reported mild beta-lactam allergy in infants

BACKGROUND

Around 10% of people report a drug allergy and avoid some medications because of fear of allergic reactions. However, only after a proper diagnostic workup can some of these reactions be confirmed as allergic or nonallergic hypersensitivities. Beta-lactams (BLs) are the most common medication suspected of being involved in drug hypersensivity reactions (DHRs) in children. Recently, direct oral provocation tests (DPT) with BLs gained popularity within pediatric populations as a tool for delabeling children with suspected BL allergies. This study aimed to evaluate the safety of direct provocation tests in infants with mild cutaneous non-immediate reactions to BLs.

METHODS

The authors retrospectively analyzed the data of 151 infants between 2015 and 2022, referred for evaluating a suspected allergy to BLs that occurred before age 24 months.

RESULTS

The mean age of the children, including 55% male kids, at the suspected reaction was 15.9 months and the mean age at the time of the DPT was 39.6 months. In most cases, antibiotics were prescribed to treat common upper respiratory infections, such as acute otitis (54.3%) and acute tonsillitis (27.2%). Amoxicillin was considered the culprit drug in 62.9% of the cases, and the combination of amoxicillin-clavulanic acid in the case of 33.8% of children. The most frequent associated cutaneous clinical manifestations were maculopapular exanthema in 74.8% and delayed urticaria/angioedema in 25.2%. Of the 151 infants evaluated, parents of 149 infants agreed for a direct DPT, and only three had a positive test (2%). Symptoms resulting from the DPT were mild and easily treatable.

CONCLUSIONS

A direct DPT without prior tests is a safe and effective procedure to delabel BL allergy, even in infants. The authors wish to emphasize the importance of properly validating BL allergy suspicions by promoting appropriate diagnostic procedures in infants as, in most cases, DHRs can be excluded and there is no need for further therapeutic restrictions.

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.

Recent findings on drug hypersensitivity in children

Drug hypersensitivity reactions (DHR) in children have a significant impact on clinical practice and public health. Both under-diagnosis (due to under-reporting) and over-diagnosis (due to the overuse of the term "allergy") are potential issues. The aim of this narrative review is to describe the most recent findings of DHR in children/adolescents and gaps regarding epidemiology, antibiotic allergy, antiepileptic hypersensitivity, vaccine allergy, and severe cutaneous adverse reactions (SCAR) in this age group.

Antibiotic use, best practice statement adherence, and UTI rate for intradetrusor onabotulinumtoxin-A injection for overactive bladder: A multi-institutional collaboration from the SUFU Research Network (SURN)

INTRODUCTION

Onabotulinumtoxin A (BTX-A) is a well-established treatment for overactive bladder (OAB). The American Urological Association (AUA) 2008 Antibiotic Best Practice Statement (BPS) recommended trimethoprim-sulfamethoxazole or fluoroquinolone for cystoscopy with manipulation. The aim of the study was to evaluate concordance with antibiotic best practices at the time of BTX-A injection and urinary tract infection (UTI) rates based on antibiotic regimen.

METHODS

Men and women undergoing first-time BTX-A injection for idiopathic OAB with 100 units in 2016, within the SUFU Research Network (SURN) multi-institutional retrospective database were included. Patients on suppressive antibiotics were excluded. The primary outcome was concordance of periprocedural antibiotic use with the AUA 2008 BPS antimicrobials of choice for "cystoscopy with manipulation." As a secondary outcome we compared the incidence of UTI among women within 30 days after BTX-A administration. Each outcome was further stratified by procedure setting (office vs. operating room; OR).

RESULTS

Of the cohort of 216 subjects (175 women, 41 men) undergoing BTX-A, 24 different periprocedural antibiotic regimens were utilized, and 98 (45%) underwent BTX-A injections in the OR setting while 118 (55%) underwent BTX-A injection in the office. Antibiotics were given to 86% of patients in the OR versus 77% in office, and 8.3% of subjects received BPS concordant antibiotics in the OR versus 82% in office. UTI rates did not vary significantly among the 141 subjects who received antibiotics and had 30-day follow-up (8% BPS-concordant vs. 16% BPS-discordant, CI -2.4% to 19%, p = 0.13). A sensitivity analysis of UTI rates based on procedure setting (office vs. OR) did not demonstrate any difference in UTI rates (p = 0.14).

CONCLUSIONS

This retrospective multi-institutional study demonstrates that antibiotic regimens and adherence to the 2008 AUA BPS were highly variable among providers with lower rates of BPS concordant antibiotic use in the OR setting. UTI rates at 30 days following BTX-A did not vary significantly based on concordance with the BPS or procedure setting.

The impact of antibiotic stewardship interventions and patient related factors on antibiotic prescribing in a vascular surgical department

PURPOSE

The development of guidelines tailored to the departments' needs and counselling during ward rounds are important antibiotic stewardship (AS) strategies. The aim was to analyse the impact of AS ward rounds and institutional guidelines as well as patient-related factors on antibiotic use in vascular surgical patients.

METHODS

A retrospective prescribing-analysis of 3 months (P1, P2) before and after implementing weekly AS ward rounds and antimicrobial treatment guidelines was performed. Choice of systemic antibiotics, days of antibiotic therapy and clinical data were obtained from electronic patient records.

RESULTS

During P2, the overall antibiotic consumption as well as the use of last-resort compounds like linezolid and fluoroquinolones decreased distinctly (overall: 47.0 days of therapy (DOT)/100 patient days (PD) vs. 35.3 DOT/100PD, linezolid: 3.7 DOT/100PD vs. 1.0 DOT/100PD, fluoroquinolones: 7.0 DOT/100PD vs. 3.2 DOT/100PD) while narrow-spectrum beta-lactams increased by 48.4%. Courses of antibiotics were de-escalated more often during P2 (30.5% vs. 12.1%, p = 0.011). Only in P2, an antibiotic therapy was initiated in patients suffering from more comorbidities (i.e. higher Charlson Comorbidity Index) more frequently. Other patient factors had no distinct impact on antibiotic prescribing.

CONCLUSION

Weekly AS ward rounds improved adherence to institutional antibiotic treatment guidelines and antibiotic prescribing in vascular surgical patients. Clear patient-related determinants affecting choice of antibiotic therapies could not be identified.

Resource utilization and cost assessment of a proactive penicillin allergy de-labeling program for low-risk inpatients

BACKGROUND

Resource utilization and costs can impede proactive assessment and de-labeling of penicillin allergy among inpatients.

METHODS

Our pilot intervention was a proactive penicillin allergy de-labeling program for new inpatients with penicillin allergy. Patients deemed appropriate for a challenge with a low-risk penicillin allergy history were administered 250 mg amoxicillin and monitored for 1 h. We performed an explorative economic evaluation using various healthcare professional wages.

RESULTS

Over two separate 2-week periods between April 2021 and March 2022, we screened 126 new inpatients with a penicillin allergy. After exclusions, 55 were appropriate for formal assessment. 19 completed the oral challenge, and 12 were directly de-labeled, resulting in a number needed to screen of 4 and a number needed to assess of 1.8 to effectively de-label one patient. The assessor's median time in the hospital per day de-labeling was 4h08 with a range of (0h05, 6h45). A single-site annual implementation would result in 715 penicillin allergy assessments with 403 patients de-labeled assuming 20,234 annual weekday admissions and an 8.9% penicillin allergy rate. Depending on the assessor used, the annual cost of administration would be between $21,476 ($53.29 per effectively de-labeled patient) for a pharmacy technician and $61,121 ($151.67 per effectively de-labeled patient) for a Nurse Practitioner or Physician Assistant.

CONCLUSION

A proactive approach, including a direct oral challenge for low-risk in-patients with penicillin allergy, appears safe and feasible. Similar programs could be implemented at other institutions across Canada to increase access to allergy assessment.

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.

Antibiotic management of urinary tract infections in the post-antibiotic era: a narrative review highlighting diagnostic and antimicrobial stewardship

BACKGROUND

As one of the most common indications for antimicrobial prescription in the community, the management of urinary tract infections (UTIs) is both complicated by, and a driver of, antimicrobial resistance.

OBJECTIVES

To highlight the key clinical decisions involved in the diagnosis and treatment of UTIs in adult women, focusing on clinical effectiveness and both diagnostic and antimicrobial stewardship as we approach the post-antimicrobial era.

SOURCES

Literature reviewed via directed PubMed searches and manual searching of the reference list for included studies to identify key references to respond to the objectives. A strict time limit was not applied. We prioritised recent publications, randomised trials, and systematic reviews (with or without meta-analyses) where available. Searches were limited to English language articles. A formal quality assessment was not performed; however, the strengths and limitations of each paper were reviewed by the authors throughout the preparation of this manuscript.

CONTENT

We discuss the management of UTIs in ambulatory adult women, with particular focus on uncomplicated infections. We address the diagnosis of UTIs, including the following: definition and categorisation; bedside assessments and point-of-care tests; and the indications for, and use of, laboratory tests. We then discuss the treatment of UTIs, including the following: indications for treatment, antimicrobial sparing approaches, key considerations when selecting a specific antimicrobial agent, specific treatment scenarios, and duration of treatment. We finally outline emerging areas of interest in this field.

IMPLICATIONS

The steady increase in antimicrobial resistance among common uropathogens has had a substantial affect on the management of UTIs. Regarding both diagnosis and treatment, the clinician must consider both the patient (clinical effectiveness and adverse effects, including collateral damage) and the community more broadly (population-level antimicrobial selection pressure).

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.

Facilitators and Barriers to Verifying Penicillin Allergies in a Veteran Nursing Home Population

BACKGROUND

Unconfirmed penicillin allergies are common and may contribute to adverse outcomes, especially in frail older patients. Evidence-based clinical pathways for evaluating penicillin allergies have been effectively and safely applied in selected settings, but not in nursing home populations.

OBJECTIVE

To identify potential facilitators and barriers to implementing a strategy to verify penicillin allergies in Veterans Health Administration nursing homes, known as Community Living Centers (CLCs).

METHODS

We conducted semistructured interviews with staff, patients, and family members at 1 CLC to assess their understanding of penicillin allergies and receptiveness to verifying the allergy. We also asked staff about the proposed allergy assessment strategy, including willingness to delabel by history and feasibility of performing oral challenges or skin testing on their unit.

RESULTS

From 24 interviews (11 front-line staff, 4 leadership, 3 patients, 6 family members), we identified several facilitators or barriers. Staff recognized the importance of allergy verification and were willing to support and assist in implementing verification strategies. The CLC residents were willing to have their allergy status verified. However, some family members expressed reluctance to verifying their relative's allergy status owing to safety concerns. Front-line staff also expressed concern over having the necessary resources, including time and expertise, to implement the strategy. Staff suggested involving clinical pharmacists and educating staff, patients, and family members as ways to overcome these barriers.

CONCLUSIONS

Concerns about safety and staff resources are important potential barriers to implementing verification strategies. Involvement of pharmacists and education of both staff and patients and family members will be important components of any successful intervention.

Proton pump inhibitors and the risk of acquiring a penicillin allergy label

The negative consequences of having a penicillin allergy label are well established. Penicillin allergy de-labelling improves healthcare outcomes; however, less attention is paid to modifying risk factors leading to penicillin allergy development. In this propensity score-matched retrospective cohort study, we used a de-identified population-based database (TriNetX Research Network) and examined the 30-day risk of acquiring a penicillin allergy label in patients using proton pump inhibitors (PPIs). We demonstrated a higher risk of acquiring a penicillin allergy label among PPI users compared to controls.

A Case of Amoxicillin-Induced Drug Reaction With Eosinophilia and Systemic Symptoms (Dress) Syndrome Associated With Significant Reactive Hypereosinophilia (HE): A Case Report

Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) syndrome is a severe cutaneous drug reaction characterized by a skin rash, eosinophilia, atypical lymphocytosis, and involvement of multiple organs. The mortality rate of DRESS syndrome is moderate, and prompt diagnosis and treatment are essential. When DRESS syndrome is presented with significant hypereosinophilia (HE), it should be differentiated from other conditions that can cause HE through a comprehensive approach to diagnostic evaluation. Amoxicillin has been well-documented as a potential cause of DRESS syndrome. It is important to note that amoxicillin can trigger DRESS syndrome in patients who already have a known allergy to sulfasalazine, as well as when it is administered with a beta-lactamase inhibitor such as clavulanic acid. Here, we describe a case of amoxicillin alone-induced DRESS syndrome associated with significant reactive HE. A 39-year-old female presented with three days of shortness of breath, fatigue, facial swelling, and a generalized maculopapular skin rash. The patient endorsed taking amoxicillin two to three weeks prior to the presentation. Diagnostic tests revealed HE, significant generalized lymphadenopathy on computed tomography (CT) scans of the neck and abdomen, and bilateral interstitial infiltration on a CT scan of the chest suggestive of eosinophilic infiltration. Based on the European Registry of Severe Cutaneous Adverse Reactions (RegiSCAR) scoring system, the case was categorized as "probable" DRESS syndrome related to amoxicillin. High-dose steroids were initiated as the treatment of choice for suspected DRESS syndrome. Other potential causes of HE were investigated and ruled out. The patient showed significant clinical improvement, with the normalization of absolute eosinophil count (AEC) and complete resolution of lung infiltrates on a repeat CT scan of the chest. The case highlights the importance of conducting a comprehensive diagnostic evaluation to differentiate DRESS syndrome from other causes of HE when significant HE is present. Prompt treatment with high-dose steroids is essential in managing patients with severe symptoms associated with DRESS syndrome. It is crucial to consider amoxicillin as a potential trigger for DRESS syndrome, even when there is no history of sulfasalazine allergy or concurrent administration of a beta-lactamase inhibitor.

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.

Digital Antibiotic Allergy Decision Support Tool Improves Management of β-Lactam Allergies

BACKGROUND

Frontline providers frequently make time-sensitive antibiotic choices, but many feel poorly equipped to handle antibiotic allergies.

OBJECTIVE

We hypothesized that a digital decision support tool could improve antibiotic selection and confidence when managing β-lactam allergies.

METHODS

A digital decision support tool was designed to guide non-allergist providers in managing patients with β-lactam allergy labels. Non-allergists were asked to make decisions in clinical test cases without the tool, and then with it. These decisions were compared using paired t tests. Users also completed surveys assessing their confidence in managing antibiotic allergies.

RESULTS

The tool's algorithm was validated by confirming its recommendations aligned with that of five allergists. Non-allergist providers (n = 102) made antibiotic management decisions in test cases, both with and without the tool. Use of the tool increased the proportion of correct decisions from 0.41 to 0.67, a difference of 0.26 (95% CI, 0.22-0.30; P < .001). Users were more likely to give full-dose antibiotics in low-risk situations, give challenge doses in medium-risk situations, and avoid the antibiotic and/or consult allergy departments in high-risk situations. A total of 98 users (96%) said the tool would increase their confidence when choosing antibiotics for patients with allergies.

CONCLUSIONS

A point-of-care clinical decision tool provides allergist-designed guidance for non-allergists and is a scalable system for addressing antibiotic allergies, irrespective of allergist availability. This tool encouraged appropriate antibiotic use in low- and medium-risk situations and increased caution in high-risk situations. A digital support tool should be considered in quality improvement and antibiotic stewardship efforts.

The Quality and Management of Penicillin Allergy Labels in Pediatric Primary Care

BACKGROUND AND OBJECTIVES

Penicillin allergy labels are the most common drug allergy label. The objective of this study was to describe the quality and management of penicillin allergy labels in the pediatric primary care setting.

METHODS

Retrospective chart review of 500 of 18 015 children with penicillin allergy labels born from January 1, 2010 to June 30, 2020 randomly selected from an outpatient birth cohort from Texas Children's Pediatrics and Children's Hospital of Philadelphia networks. Penicillin allergy risk classification ("not allergy," "low risk," "moderate or high risk," "severe risk," "unable to classify") was determined based on documentation within (1) the allergy tab and (2) electronic healthcare notes. Outcomes of allergy referrals and penicillin re-exposure were noted.

RESULTS

Half of penicillin allergy labels were "unable to classify" based on allergy tab documentation. Risk classification agreement between allergy tabs and healthcare notes was fair (Cohen's ĸ = 0.35 ± 0.02). Primary care physicians referred 84 of 500 (16.8%) children to an allergist, but only 54 (10.8%) were seen in allergy clinic. All children who were challenged (25 of 25) passed skin testing. Removal of allergy labels was uncommon (69 of 500, 13.8%) but occurred more often following allergy appointments (26 of 54, 48%) than not (43 of 446, 9.6%, P < .001). Children delabeled by primary care physicians were as likely to tolerate subsequent penicillin-class antibiotics as those delabeled by an allergist (94% vs 93%, P = .87).

CONCLUSIONS

Penicillin allergy documentation within the allergy tab was uninformative, and children were infrequently referred to allergists. Future quality improvement studies should improve penicillin allergy documentation and expand access to allergy services.

Outcome of preoperative cefazolin use for infection prophylaxis in patients with self-reported penicillin allergy

BACKGROUND

Cephalosporins are the preferred antibiotics for prophylaxis against surgical site infections. Most studies give a rate of combined IgE and non-IgE penicillin allergy yet it is recommended that cephalosporins be avoided in patients having the former but can be used in those with the latter. Some studies use penicillin allergy while others penicillin family allergy rates. The primary goal of this study was to determine the rates of IgE and non-IgE allergy as well as cross reactions to both penicillin and the penicillin family. Secondary goals were to determine the surgical services giving preoperative cefazolin and the types of self reported reactions that patients' had to penicillin prompting their allergy status.

METHODS

All patients undergoing elective and emergency surgery at a University Health Sciences Centre were retrospectively studied. The hospital electronic medical record was used for data collection.

RESULTS

8.9% of our patients reported non-IgE reactions to penicillin with a cross reactivity rate of 0.9% with cefazolin. 4.0% of our patients reported IgE reactions to penicillin with a cross reactivity rate of 4.0% with cefazolin. 10.5% of our patients reported non-IgE reactions to the penicillin family with a cross reactivity rate of 0.8% with cefazolin. 4.3% of our patients reported IgE reactions to the penicillin family with a cross reactivity rate of 4.0% with cefazolin.

CONCLUSIONS

Our rate of combined IgE and non-IgE reactions for both penicillin and penicillin family allergy was within the range reported in the literature. Our rate of cross reactivity between cefazolin and combined IgE and non-IgE allergy both to penicillin and the penicillin family were lower than reported in the old literature but within the range of the newer literature. We found a lower rate of allergic reaction to a cephalosporin than reported in the literature. We documented a wide range of IgE and non-IgE reactions. We also demonstrated that cefazolin is frequently the preferred antibiotics for prophylaxis against surgical site infections by many surgical services and that de-labelling patients with penicillin allergy is unnecessary.

Impact of Patient-Reported Penicillin Allergy on Antibiotic Prophylaxis and Surgical Site Infection Among Patients Undergoing Colorectal Surgery

BACKGROUND

Surgical site infections are a major preventable source of morbidity, mortality, and increased health care expenditures after colorectal surgery. Patients with penicillin allergy may not receive the recommended preoperative antibiotics, putting them at increased risk for surgical site infections.

OBJECTIVE

This study aimed to evaluate the impact of patient-reported penicillin allergy on preoperative antibiotic prophylaxis and surgical site infection rates among patients undergoing major colon and rectal procedures.

DESIGN

This is a retrospective observational study.

SETTING

This study was conducted at a tertiary teaching hospital in Dallas.

PATIENTS

Adults undergoing colectomy or proctectomy between July 2012 and July 2019 were included.

MAIN OUTCOME MEASURES

The primary outcomes measured were preoperative antibiotic choice and surgical site infection.

RESULTS

Among 2198 patients included in the study, 12.26% (n = 307) reported a penicillin allergy. Patients with penicillin allergy were more likely to be white (82%) and female (54%; p < 0.01). The most common type of allergic reaction reported was rash (36.5%), whereas 7.2% of patients reported anaphylaxis. Patients with self-reported penicillin allergy were less likely to receive beta-lactam antibiotics than patients who did not report a penicillin allergy (79.8% vs 96.7%, p < 0.001). Overall, 143 (6.5%) patients had surgical site infections. On multivariable logistic regression, there was no difference in rates of surgical site infection between patients with penicillin allergy vs those without penicillin allergy (adjusted OR 1.14; 95% CI, 0.71-1.82).

LIMITATIONS

A limitation of this study was its retrospective study design.

CONCLUSIONS

Self-reported penicillin allergy among patients undergoing colorectal surgery is common; however, only a small number of these patients report any serious adverse reactions. Patients with self-reported penicillin allergy are less likely to receive beta-lactam antibiotics and more likely to receive non-beta-lactam antibiotics. However, this does not affect the rate of surgical site infection among these patients, and these patients can be safely prescribed non-beta-lactam antibiotics without negatively impacting surgical site infection rates. See Video Abstract at http://links.lww.com/DCR/B838 .IMPACTO DE LA ALERGIA A LA PENICILINA INFORMADA POR EL PACIENTE EN LA PROFILAXIS ANTIBIÓTICA Y LA INFECCIÓN DEL SITIO OPERATORIO ENTRE PACIENTES DE CIRUGÍA COLORECTAL.

ANTECEDENTES

Las infecciones del sitio operatorio son una de las principales fuentes prevenibles de morbilidad, mortalidad y aumento del gasto sanitario después de cirugía colorrectal. Es posible que los pacientes con alergia a la penicilina no reciban los antibióticos preoperatorios recomendados, lo que los pone en mayor riesgo de infecciones en el sitio operatorio.

OBJETIVO

Este estudio tuvo como objetivo evaluar el impacto de la alergia a la penicilina informada por el paciente sobre la profilaxis antibiótica preoperatoria y las tasas de infección del sitio operatorio entre pacientes sometidos a procedimientos mayores de colon y recto.

DISEO

Estudio observacional retrospectivo.

AJUSTE

Hospital universitario terciario en Dallas.

PACIENTES

Adultos sometidos a colectomía o proctectomía entre julio de 2012 a julio de 2019.

PRINCIPALES MEDIDAS DE DESENLACE

Elección de antibióticos preoperatorios e infección del sitio operatorio.

RESULTADOS

Entre los 2198 pacientes incluidos en el estudio, el 12,26% (n = 307) informó alergia a la penicilina. Los pacientes con alergia a la penicilina tenían más probabilidades de ser blancos (82%) y mujeres (54%) ( p < 0,01). El tipo más común de reacción alérgica notificada fue erupción cutánea (36,5%), mientras que el 7,2% de los pacientes notificó anafilaxia. Los pacientes con alergia a la penicilina autoinformada tenían menos probabilidades de recibir antibióticos betalactámicos en comparación con los pacientes que no informaron alergia a la penicilina (79,8% frente a 96,7%, p < 0,001). En general, hubo 143 (6,5%) pacientes con infecciones del sitio operatorio. En la regresión logística multivariable no hubo diferencias en las tasas de infección del sitio operatorio entre los pacientes con alergia a la penicilina frente a los que no tenían alergia a la penicilina (razón de probabilidades ajustada 1,14; intervalo de confianza del 95%, 0,71-1,82).

LIMITACIONES

Diseño de estudio retrospectivo.

CONCLUSIONES

La alergia a la penicilina autoinformada entre los pacientes de cirugía colorrectal es común, sin embargo, solo un pequeño número de estos pacientes informan reacciones adversas graves. Los pacientes con alergia a la penicilina autoinformada tienen menos probabilidades de recibir antibióticos betalactámicos y más probabilidades de recibir antibióticos no betalactámicos. Sin embargo, esto no afecta la tasa de infección del sitio quirúrgico entre estos pacientes y se les puede recetar de forma segura con antibióticos no betalactámicos sin afectar negativamente las tasas de infección del sitio quirúrgico. Consulte Video Resumen en http://links.lww.com/DCR/B838 . (Traducción-Dr. Juan Carlos Reyes ).

Feasibility of trimethoprim/sulfamethoxazole desensitization therapy in hematological diseases

The effectiveness and safety of trimethoprim/sulfamethoxazole (TMP/SMX) desensitization therapy is insufficiently evaluated in hematological diseases. From 2002 to 2019, we retrospectively analyzed 112 patients with hematological diseases who underwent desensitization therapy after TMP/SMX prophylaxis withdrawal due to adverse events. They orally started TMP/SMX at 0.4 mg/2 mg, which was then increased daily to 80 mg/400 mg for 5 or 9 days. Eighty-eight patients (79%) had complete desensitization, and the major reason for failure was rash seen in 21 cases (19%). The cause of desensitization and reasons for failure matched in 22 cases (92%). Pneumocystis pneumonia was not observed throughout the study. In the failure group, the number of eosinophils and alanine aminotransferase (ALT) levels were significantly increased after desensitization. In particular in the failure group, the slight increase in eosinophils was seen through the beginning to halfway during desensitization (36/μL (0-900/μL) and 48/μL (0-2560/μL), respectively, p = 0.025). These data show that TMP/SMX desensitization therapy is effective and safe in hematological diseases. The recurrence of adverse events could help predict desensitization success.

The Impact of Reported β-Lactam Allergy on Clinical Outcomes and Antibiotic Use Among Solid Organ Transplant Recipients

Background

Reported β-lactam allergies (BLAs) are common and frequently inaccurate, but there are limited data on the clinical implications of BLA among solid organ transplant (SOT) recipients. We examined the impact of BLA on clinical outcomes and antibiotic use among SOT recipients.

Methods

This retrospective cohort study included adult patients undergoing single-organ heart, kidney, liver, lung, or pancreas transplant at a United States academic medical center from 1 April 2017 to 31 December 2020. Demographic and clinical data were collected from the electronic health record. Multivariate median regression was performed to evaluate the association between BLA and days alive and out of the hospital in the first 180 days posttransplant (DAOH180). Multivariate logistic regression was performed to evaluate the association between BLA and antibiotic use.

Results

Among 1700 SOT recipients, 285 (16.8%) had a BLA at the time of transplant. BLA was not associated with DAOH180 (adjusted median difference, -0.8 days [95% confidence interval {CI}, -2.7 to 1.2]; P = .43). Patients with BLA were more likely to receive intravenous vancomycin (adjusted odds ratio [aOR], 1.8 [95% CI, 1.3-2.6]; P < .001), clindamycin (aOR, 9.9 [95% CI, 5.1-18.9]; P < .001), aztreonam (aOR, 19.6 [95% CI, 5.9-64.4]; P < .001), fluoroquinolones (aOR, 3.8 [95% CI, 2.8-5.0]; P < .001), or aminoglycosides (aOR, 3.9 [95% CI, 2.5-6.2]; P < .001).

Conclusions

BLA was associated with use of β-lactam alternative antibiotics but not DAOH180 among SOT recipients.

Amoxicillin hypersensitivity: patient outcomes in a seven-year retrospective study

BACKGROUND

The beta-lactam antibiotic amoxicillin and the beta-lactamase inhibitor clavulanic acid in combination with amoxicillin are known to both cause immediate and non-immediate type hypersensitivity.

OBJECTIVE

To characterize a large cohort of patients with a history of amoxicillin or amoxicillin-clavulanic acid hypersensitivity.

METHODS

Retrospective analysis of demographics, presentation, investigation, and management of 331 patients presenting to one allergy center with a history of hypersensitivity to amoxicillin or amoxicillin-clavulanic acid.

RESULTS

Hypersensitivity was confirmed in 37/221 (17%) patients who took amoxicillin and 47/110 (43%) patients who took amoxicillin-clavulanic acid as the index drug. In immediate hypersensitivity, skin testing confirmed the diagnosis in 66/139 (47%) patients. Penicillin cross-reactivity was observed in 16/36 (44%). 13/16 (81%) cross-reactive patients reacted to amoxicillin-clavulanic acid as the index drug. All skin test negative patients (73/139) underwent drug provocation. The negative predictive value of skin tests was 89%. In non-immediate hypersensitivity, delayed intradermal tests confirmed diagnosis in 12/170 (7%). 8/12 (67%) skin test positive patients presented with DRESS. All skin test negative patients (158/170) underwent drug provocation. The negative predictive value of skin tests was 95%. Penicillin cross-reactivity was observed in 3/12 (25%). Ten patients were diagnosed with hypersensitivity to clavulanic acid.

CONCLUSION

The negative predictive value of skin tests in both immediate and non-immediate hypersensitivity reactions is excellent and excludes severe allergy. Non-immediate hypersensitivity is rare. Confirmed hypersensitivity is more likely if amoxicillin-clavulanic acid is the index drug. Cross-reactivity was more common in patients presenting with immediate hypersensitivity, most commonly involving benzylpenicillin. A minority of patients were allergic to clavulanic acid.

Association of Sociodemographic Factors With Reported Penicillin Allergy in Pediatric Inpatients

OBJECTIVES

Characterize the association of sociodemographic factors with reported penicillin allergy in pediatric inpatients.

METHODS

We conducted a retrospective cohort study of pediatric inpatients admitted to general pediatric units at an academic medical center with reported penicillin allergy and reaction history. Sociodemographic factors evaluated were gender, age, race, ethnicity, language, and insurance payer. We conducted univariable and multivariable logistic regression models to evaluate associations between demographic variables and penicillin allergy.

RESULTS

Of 3890 pediatric inpatients, 299 (7.7%) had a reported penicillin allergy. The majority of documented reaction histories were hives, rash, or unknown. In univariable analysis, odds of penicillin allergy were lower in patients who identify as Black and who prefer a language other than English, and higher in patients of non-Hispanic/Latino ethnicity, those with private insurance, and with increasing age. In multivariable logistic regression, only Black race (adjusted odds ratio 0.42, 95% confidence interval CI 0.30-0.59) and young age were significantly associated with lower odds of penicillin allergy.

CONCLUSIONS

After adjustment for covariates, Black race was associated with lower odds of reported penicillin allergy in hospitalized children. Penicillin allergy reporting may be an indicator of racial differences in the prescribing of antimicrobial agents, patient-clinician communication, and access to health care.

Impact of Fungal Spores on Asthma Prevalence and Hospitalization

Despite making up a significant proportion of airborne allergens, the relationship between fungal spores and asthma is not fully explored. Only 80 taxa of fungi have so far been observed to exacerbate respiratory presentations, with Cladosporium spp., Aspergillus spp., Penicillium spp., and Alternaria spp. found to comprise the predominant allergenic airborne spores. Fungal spores have been found in indoor environments, such as hospitals and housing due to poor ventilation. Meanwhile, outdoor fungal spores exhibit greater diversity, and higher abundance and have been associated with hospitalizations from acute asthma presentations. In addition, fungal spores may be the underlying, and perhaps the “missing link”, factor influencing the heightened rate of asthma presentations during epidemic thunderstorm asthma events. To improve our knowledge gap on fungal spores, airborne allergen monitoring must be improved to include not only dominant allergenic fungi but also provide real-time data to accurately and quickly warn the general public. Such data will help prevent future asthma exacerbations and thus save lives. In this review, we examine the health risks of prominent allergenic fungal taxa, the factors influencing spore dispersal and distribution, and why improvements should be made to current sampling methods for public health and wellbeing.

Management of Beta-Lactam Antibiotics Allergy: A Real-Life Study

Beta-lactam allergy is a common problem in everyday medical practice and is recognized as a major public health issue. Carrying this label frequently leads to the avoidance of all beta-lactam antibiotics, favoring the use of other less preferred classes of antibiotics, that are more expensive and associated with more side effects and increased antimicrobial resistance. Therefore, delabeling a beta-lactam allergy is part of antimicrobial stewardship programs. Herein, we retrospectively examined the clinical records of 576 patients who were referred to our center for a label of allergy to beta-lactam antibiotics and were systematically investigated following a standardized algorithm. Our main aim was to evaluate the frequency of confirmed immediate- and delayed-type allergy to commonly prescribed subclasses of beta-lactam antibiotics (penicillin and cephalosporin), as well as the negative predictive value (NPV) and the sensitivity of skin tests. Our secondary aims were to examine the safety of beta-lactam skin testing and drug challenge. We identified that 260 patients reported a history of immediate reactions, 131 of delayed reactions, and 114 of unknown timing or mechanism of reactions. Following assessment and testing, 86 (18.3%) patients had a confirmed allergy to any beta-lactam antibiotics; 63 (13.4%) with an immediate- and 23 (4.9%) with a delayed-type reaction. Most frequently identified confirmed allergy was to penicillins (65 patients), followed by cephalosporins (21 patients). When immediate-type reactions were examined, NPV of skin tests were 96.3% and 100% for penicillins and cephalosporins, respectively. When delayed reactions were considered, NPV were 91.9 and 87.5% for penicillins and cephalosporins, respectively. Evaluation of the safety of skin tests according to the standardized procedure showed that systemic allergic reactions occurred in only 0.7% of skin tests and in 3.1% of drug challenges. Overall, our data indicate that only 18.3% of patients with a beta-lactam allergy label have a confirmed allergy and non-allergic patients can be safely delabeled through allergic workup based on skin tests and drug challenge. This approach supports the policy of saving second-line antibiotics through a standardized allergy workup.

Factors Associated With Penicillin Allergy Labels in Electronic Health Records of Children in 2 Large US Pediatric Primary Care Networks

Importance

Penicillin allergy labels influence clinical decision-making, yet most children who are labeled do not have type 1 hypersensitivity allergic reactions and instead have a history of predictable adverse reactions or unspecified illness symptoms while receiving penicillin for viral infections. Studies describing penicillin allergy labeling in the pediatric outpatient setting are lacking.

Objective

To describe the epidemiology and factors associated with penicillin allergy labels across 2 large US pediatric primary care networks.

Design, Setting, and Participants

This retrospective, longitudinal birth cohort study was conducted in 90 primary care pediatric practices serving a diverse population of children across Houston, Texas, Austin, Texas, Philadelphia, Pennsylvania, and parts of New Jersey. Participants were children born between January 2010 and June 2020 who had a health care visit in the first 14 days of life and at least 2 additional visits in the first year of life at one of 90 primary care pediatric practices. Censoring criteria were additionally applied to exclude data from children no longer seeking health care in the 90 clinics over time. Statistical analysis was performed from February to May 2021.

Exposures

Basic patient demographics, health care utilization, penicillin exposure, and primary clinic location.

Main Outcomes and Measures

Addition of penicillin allergy label in the electronic medical record.

Results

Among 334 465 children in the birth cohort, 164 173 (49.1%) were female; 72 831 (21.8%) were Hispanic, 59 598 (17.8%) were non-Hispanic Black, and 148 534 (44.4%) were non-Hispanic White; the median (IQR) age at censoring was 3.8 (1.7-6.6) years; 18 015 (5.4%) were labeled as penicillin allergic, but the prevalence of penicillin allergy labeling ranged from 0.9% to 10.2% across practices. Children were labeled at a median (IQR) age of 1.3 (0.9-2.3) years. Non-Hispanic White children were more likely to be labeled compared with non-Hispanic Black children after controlling for potential confounders (adjusted odds ratio, 1.7 [95% CI, 1.6-1.8]). There were 6797 allergic children (37.7%) labeled after receiving 1 penicillin prescription and 1423 (7.9%) labeled after receiving 0 penicillin prescriptions.

Conclusions and Relevance

In this cohort study of more than 330 000 children, penicillin allergy labeling was common and varied widely across practices. Children were labeled early in life, and almost half were labeled after receiving 1 or 0 penicillin prescriptions. These findings raise questions regarding the validity of penicillin allergy labels. Future work exploring the fidelity of and outcomes associated with penicillin allergy-labeling in children is warranted.

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.

Outcomes in hospitalised patients with sepsis, severe sepsis or septic shock and reported penicillin allergy: a retrospective cohort study

OBJECTIVE

To determine outcomes in hospitalised patients with sepsis and reported penicillin allergy (PcnA).

DESIGN

Observational retrospective cohort study using data from electronic health records.

SETTING

A large single health system with 11 hospitals of small, medium and large sizes including a 630-bed tertiary care teaching hospital.

PARTICIPANTS

Patients (n=5238) ≥18 years of age, hospitalised with sepsis, severe sepsis or septic shock between 1 January 2016 and 31 December 2018, received antibacterial agents, and had documented PcnA status. Patients <18 years of age at admission were excluded.

OUTCOME MEASURES

Primary outcomes evaluated were inpatient mortality and 30-day mortality posthospital discharge. Secondary outcomes were hospital length of stay, 30-day readmissions, duration of antibiotic use, rate of Clostridium difficile infection and total cost of care.

RESULTS

There was no difference in outcomes including inpatient or 30-day mortality, hospital length of stay, in-hospital antibiotic duration, C. difficile infection, total cost of care and 30-day readmission rate between patients labelled with a PcnA vs patients who did not report PcnA (non-PcnA).

CONCLUSION

In this retrospective single health system study, there was no difference in key outcomes including inpatient or 30-day mortality in patients admitted with sepsis and reported PcnA compared with patients who reported no PcnA.

Drug Allergy Delabeling Programs: Recent Strategies and Targeted Populations

Drug allergy delabeling programs have become an essential element of antibiotic stewardship. Development of delabeling programs involves careful selection of target patient population, thoughtful design of delabeling approach, stakeholder engagement, assembly of key team members, implementation, and evaluation of clinical and safety outcomes. Recent programs have targeted patients thought to be most likely to benefit from removal of inaccurate antibiotic allergy labels, those with β-lactam antibiotic allergies and high-risk populations likely to need β-lactam antibiotics as first-line treatment. This review provides an overview of current risk stratification methods and β-lactam cross-reactivity data and summarizes how different inpatient and outpatient delabeling programs have used these concepts in delabeling algorithms. β-Lactam delabeling programs for inpatients, pediatric patients, and programs utilizing telehealth have been implemented with good outcomes. This review also focuses on delabeling programs for high-risk populations likely to benefit from first-line β-lactam antibiotics. These populations include perioperative, prenatal, and immunocompromised patients. Delabeling programs have been successful in the inpatient and outpatient settings at enabling appropriate antibiotic use. This article reviews delabeling strategies utilized by these programs with a focus on highlighting elements key to their success and future areas for innovation.

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.

Impact analysis of expanding narrow-spectrum antibiotic use for children with ear, sinus and throat infections

Aim: Estimate the impacts treating acute respiratory tract infections (ARTIs) in children aged 6 months through 12 years with narrow-spectrum antibiotics. Materials & methods: Decision-tree model to estimate children's health, healthcare utilization and costs, and caregiver's time and costs for using narrow-spectrum antibiotics in eligible children with an ARTI, compared with current use of narrow- and broad-spectrum antibiotics. Results: Reduced adverse drug reactions by 35,750 (14%) cases) and 4750 (12%) fewer emergency department visits, 300 (12%) fewer hospitalizations, and 50,500 (10%) avoided outpatient visits. Annual healthcare costs fell by US$120 million (22%). Total societal costs declined by US$131 million (20%). Conclusion: National implementation of narrow-spectrum antibiotics to treat ARTIs in children improves patient outcomes and reduces caregiver burden and annual healthcare costs.

Implementation and Impact of a β-Lactam Allergy Assessment Protocol in a Veteran Population

Background

Approximately 10% of the US population reports having a β-lactam allergy, although nearly 90% do not have a true immunoglobulin E (IgE)-mediated reaction. This misconception results in using nonpreferred antibiotics, leading to antimicrobial resistance and treatment failure. To evaluate, clarify, and clear β-lactam allergies, we implemented a pharmacist-driven β-lactam allergy assessment (BLAA) protocol and penicillin allergy clinic (PAC). The purpose of this study was to illustrate the BLAA process, including the pharmacist-run PAC, and assess the impact on allergy clearance.

Methods

Clinical pharmacy specialists (CPS) evaluated hospitalized veterans with β-lactam allergies, using the BLAA protocol. Eligible patients could later be seen in PAC. This was a retrospective observational review of the BLAA protocol to assess recommendations for β-lactam antibiotic use and PAC outcomes.

Results

Between November 2017 and February 2020, 278 patients were evaluated, and 32 were seen in the clinic. The most common allergen was penicillin, and the most reported reaction was a rash (27%) or pruritus and urticaria (18%). Through PAC and the BLAA protocol, 86 patients (31%) were cleared for allergy removal, and 188 (68%) were cleared for alternative β-lactams. The evaluation revealed that 274 patients (99%) were eligible to receive a β-lactam antibiotic, and only 4 patients (1%) were recommended for avoidance of all β-lactams.

Conclusions

These findings highlight the utility of the pharmacist-driven BLAA protocol. We illustrated that most patients with documented β-lactam allergies were eligible for alternative β-lactams. The implementation of the BLAA protocol and pharmacist-run PAC facilitated allergy clearance and has the potential to promote alternative β-lactam use.

Impact of Cefazolin Shortage on Clinical Outcomes of Adult Patients with Bacteremia Caused by Methicillin-Susceptible Staphylococcus aureus in a Tertiary Care University Hospital

Cefazolin is an essential antibiotic used for treating bacteremia; in particular, it is recommended as a first-line agent for infections caused by methicillin-susceptible Staphylococcusaureus (MSSA). In March 2019, problems with a major antibiotic supplier caused a critical shortage of cefazolin in Japan; however, the impact of the cefazolin shortage on clinical outcomes remains unknown. This study aimed to evaluate the effect of the cefazolin shortage in patients with MSSA bacteremia. Data from 75 patients were compared between the pre-shortage (March 2018–January 2019, n = 39) and post-shortage (March 2019–January 2020, n = 36) periods. There were no significant differences in the demographic characteristics between the two groups, and the cefazolin shortage did not worsen clinical outcomes such as adverse drug reactions, treatment failure, and 30-day mortality. In the post-shortage group, ampicillin/sulbactam and benzylpenicillin were more frequently administered as alternative antibiotics for empirical and definitive therapy (10% vs. 31%, p = 0.042; 0% vs. 19%, p = 0.004, respectively). Multivariate analysis revealed that the broad-spectrum antibiotics for definitive therapy, such as antipseudomonal penicillin, were associated with treatment failure in patients with MSSA bacteremia (OR = 17, p = 0.003). Hence, narrow-spectrum antibiotics should be prescribed for MSSA bacteremia as alternatives during a cefazolin shortage.

Direct Challenges for the Evaluation of Beta-Lactam Allergy: Evidence and Conditions for Not Performing Skin Testing

In the western world, up to 10% of the general population and more than 15% of hospitalized patients report penicillin allergy. After a comprehensive evaluation, more than 95% of patients who report a penicillin allergy can subsequently tolerate this antibiotic. Traditionally, the most widely accepted protocol to evaluate beta-lactam (BL) allergy consisted of skin testing (ST) followed by a drug provocation test (DPT) in ST-negative patients. DPT is the gold standard for proving or excluding BL allergy and is considered the final and definitive step in the evaluation. Recently, studies have been published that support the use of direct DPTs without preceding ST for both pediatric and adult patients who report a low-risk historical reaction to BLs. However, these studies use various risk-stratification criteria to determine eligibility for a direct DPT. A standardized protocol for DPT is also lacking. In this review, we assess the current literature and evidence for performing direct DPT in the pediatric and adult populations. On the basis of this evidence, we also present risk-based algorithms for the evaluation of BL allergy in pediatric and adult populations based on a description of the historical reaction.

Burden of antibiotic allergy labels in Australian aged care residents: Findings from a national point-prevalence survey

OBJECTIVE

To determine the prevalence of antibiotic allergy labels (AALs) in Australian aged care residents and to describe the impact of labels on antibiotic prescribing practices.

DESIGN

Point-prevalence survey.

SETTING

Australian residential aged care facilities.

PARTICIPANTS

We surveyed 1,489 residents in 407 aged care facilities.

METHODS

Standardized data were collected on a single day between June 1 and August 31, 2018, for residents prescribed an antibiotic. An AAL was reported if it was documented in the resident's health record. Resident-level data were used to calculate overall prevalence, and antibiotic-level data were used to report relative frequency of AALs for individual antibiotics and classes.

RESULTS

Among 1,489 residents, 356 (24%) had 1 or more documented AALs. The AALs for penicillin (28.3%), amoxicillin or amoxicillin/clavulanic acid (10.5%), cefalexin (7.2%), and trimethoprim (7.0%) were most commonly reported. The presence of an AAL was associated with significantly less prescribing of penicillins (OR, 0.43; 95% CI, 0.31-0.62; P < .001) and significantly more prescribing of lincosamides (OR, 4.81; P < .001), macrolides (OR, 2.03; P = .007), and tetracyclines (OR, 1.54; P = .033). Of residents with AALs, 7 residents (1.9%) were prescribed an antibiotic that was listed on the allergy section of their health record.

CONCLUSIONS

A high prevalence of AALs was observed among residents of Australian aged care facilities, comparable to the prevalence of AALs in high-risk hospitalized patients. Significant increases in prescribing of lincosamide, macrolide, and tetracycline agents poses a potential risk to aged populations, and future studies must evaluate the benefits of AAL delabelling programs tailored for aged care settings.

Impact of Antibiotic Allergy Labels on Patient Outcomes in a Tertiary Paediatric Hospital

OBJECTIVES

Antibiotic allergies are reported in 5 to 15% of children. This study aimed to evaluate the impact of common β-lactam antibiotic allergy labels (AALs) on hospital treatment, focussing on length of stay and appropriateness of antibiotic prescribing.

STUDY DESIGN

Retrospective cohort study over 21-months at the Royal Children's Hospital Melbourne, Australia. A subset of children with the most common β-lactam allergies, and who required admission for intravenous antibiotics over a 12-month period, was analysed for appropriateness of prescribing. Non-allergic patients were matched to evaluate associations between AALs and hospital treatment.

RESULTS

There were 98,912 children admitted over the study period, of whom 938 (1%) had at least one AAL on first admission. Of all encounters, 5145 (2.5%) were for children with AALs. The most common AALs were to amoxicillin and amoxicillin-clavulanic acid combinations (40.8%), cefalexin (14.4%) and trimethoprim-sulfamethoxazole (9.7%). For the subset, there were 66 admissions for children who required intravenous antibiotics. Documentation was adequate for 27% of AALs. Inappropriate prescribing occurred in almost half (47%). Hospital stay was longer for children with AALs (median 4.7 days; IQR 2.3 to 9.2) compared to non-allergic controls (median 3.9 days; IQR 1.9 to 6.8; P=0.02). Children with AALs were more likely to receive restricted antibiotics (aOR 3.03; 95%CI, 1.45 to 6.30; p=0.003).

CONCLUSION

This is the first study to demonstrate high rates of inappropriate prescribing in children with AALs. Children with AALs were significantly more likely to receive restricted antibiotics and had a longer length of stay compared with non-allergic controls.

A Quality Improvement Initiative to Improve Primary Care Referral Rates for Penicillin Allergy Delabeling

BACKGROUND

10% of the U.S. population report a penicillin allergy but >90% can ultimately tolerate penicillin. Confirmation of these allergies in the pediatric population may improve future health outcomes and decrease costs. Referring patients for confirmatory testing is the first step in clarifying penicillin allergies.

OBJECTIVE

Utilizing an educational session and a Best Practices Advisory (BPA) in the electronic medical record (EMR) to increase the number of referrals of patients with listed penicillin allergies from the UCSD Academic General Pediatrics (AGP) clinics to Rady Children's Hospital Allergy clinics.

METHODS

An educational session with attendings and three Plan-Do-Study-Act (PDSA) cycles were completed utilizing a best practice advisory (BPA) alert which triggered for all patients with a documented penicillin-class drug allergy to draw attention and facilitate referral. The BPA was modified at each PDSA cycle based on physician input.

RESULTS

At baseline, 1.9% of referrals to Allergy Clinic were for penicillin-class drug allergies. Following an attending physician educational session, the percentage increased to 13.7%. The BPA was implemented with further increase to 27.8% of all allergy referrals over the course of three PDSA cycles. Not all patients with penicillinclass drug allergies were referred and the reasons were documented when the physicians dismissed the BPA. 35% of the time, physicians did not refer because of time constraints as opposed to patient/parent disinterest which was 8% of the time.

CONCLUSION

Referrals to the allergist for confirmatory testing in patients with listed penicillin allergies increased by more than 10 fold. This study illustrates successful tools to support delabeling.

Implementing a new antibiotic allergy protocol in clinical practice: well-trusted but not used

Background

Suboptimal antibiotic prescriptions in patients with an antibiotic allergy label lead to increased incidence of adverse events and antimicrobial resistance (AMR). An antibiotic allergy protocol was developed in a Dutch academic hospital guiding optimal and safe antibiotic use in potentially penicillin-allergic patients. Informed by previous studies of implementation processes in clinical care, we studied the implementation of this protocol.

Methods

Medical professionals in the Departments of Surgery, Internal Medicine, and Pulmonary Care were interviewed. Additionally, focus groups were conducted in Internal Medicine and Pulmonary Care to validate the outcomes of the interviews.

Results

Dissemination of the protocol via the regular online hospital-wide guidance system did not have a significant impact on the knowledge about or use of the protocol. If healthcare professionals found the protocol, they thought it was valuable and expressed trust in the expertise embodied in it. However, its use in practice was rather minimal. Interviewees doubted the accuracy of the patient’s histories about their previous adverse drug reactions, and/or the information in their medical records and concluded that adherence to the expert guideline was needlessly risky. They felt the acute allergic reaction risk for a patient outweighed the risk of suboptimal therapy or future AMR.

Conclusions

For successful implementation and dissemination of the protocol, the accessibility of the protocol, the information about the actual risks of following the protocol and the registration of allergic history should be improved. However, whether this actually results in improvement also depends on changes in the hospital culture and organization.

Impact of an Antibiotic Side-Chain-Based Cross-reactivity Chart Combined With Enhanced Allergy Assessment Processes for Surgical Prophylaxis Antimicrobials in Patients With β-Lactam Allergies

BACKGROUND

β-Lactam antibiotics are first-line therapy for perioperative prophylaxis; however, patient-reported allergies often lead to increased prescribing of alternative antibiotics that may increase the incidence of surgical site infections. The R-group side chain of the β-lactam ring is responsible for allergic cross-reactivity and experts recommend the use of β-lactams that are structurally dissimilar.

METHODS

An internally developed, antibiotic side-chain-based cross-reactivity chart was developed and implemented alongside enhanced allergy assessment processes. This single-center, quasi-experimental study analyzed antibiotic prescribing in all adult patients with a documented β-lactam allergy undergoing an inpatient surgical procedure between quartile (Q) 1 (2012)-Q3 (2014) (historical group) and Q3 (2016)-Q3 (2018) (intervention group). Propensity-weighted scoring analyses compared categorical and continuous outcomes. Interrupted time-series analysis further analyzed key outcomes.

RESULTS

A total of 1119 and 1089 patients were included in the historical and intervention cohorts, respectively. There was a significant difference in patients receiving a β-lactam alternative antibiotic between cohorts (84.9% vs 15.1%; P < .001). There was a decrease in 30-day readmissions in the intervention cohort (7.9% vs 6.3%; P = .035); however, there was no difference in the incidence of SSIs in patients readmitted (14.8% vs 13%; P = .765). No significant differences were observed in allergic reactions (0.5% vs 0.3%; P = .323), surgical site infections, in-hospital and 30-day mortality, healthcare facility-onset Clostridiodes difficile infection, acute kidney injury, or hospital costs.

CONCLUSIONS

Implementation of an antibiotic cross-reactivity chart combined with enhanced allergy assessment processes significantly improved the prescribing of β-lactam antibiotics for surgical prophylaxis.

Macrolides: From Toxins to Therapeutics

Macrolides are a diverse class of hydrophobic compounds characterized by a macrocyclic lactone ring and distinguished by variable side chains/groups. Some of the most well characterized macrolides are toxins produced by marine bacteria, sea sponges, and other species. Many marine macrolide toxins act as biomimetic molecules to natural actin-binding proteins, affecting actin polymerization, while other toxins act on different cytoskeletal components. The disruption of natural cytoskeletal processes affects cell motility and cytokinesis, and can result in cellular death. While many macrolides are toxic in nature, others have been shown to display therapeutic properties. Indeed, some of the most well known antibiotic compounds, including erythromycin, are macrolides. In addition to antibiotic properties, macrolides have been shown to display antiviral, antiparasitic, antifungal, and immunosuppressive actions. Here, we review each functional class of macrolides for their common structures, mechanisms of action, pharmacology, and human cellular targets.