Point-of-Care β-Lactam Allergy Skin Testing by Antimicrobial Stewardship Programs: A Pragmatic Multicenter Prospective Evaluation

Leveraging implementation science theories to develop and expand the use of a penicillin allergy de-labeling intervention

BACKGROUND

Penicillin allergy is the most frequently reported drug allergy, yet most patients can tolerate the drug if challenged. Despite this discrepancy, large scale penicillin allergy de-labeling interventions have not been widely implemented in many health care systems. The application of a multi-method implementation science approach can provide key tools to study this evidence to practice gap and provide insight to successfully operationalize penicillin allergy evaluation in real-world clinical settings.

METHODS

We followed a four-step process that leverages qualitative analysis to design evidence-based, actionable strategies to develop an intervention. First, we specified the clinician-perceived barriers to penicillin allergy de-labeling (intervention targets). We then mapped intervention targets onto Theoretical Domains Framework (domains and constructs) and found the root causes of behavior. Next, we linked root causes of behavior with intervention functions (BCW). In the final step, we synthesized participants' suggestions for process improvement with implementation strategies aligning with the intervention functions.

RESULTS

Evidence-based strategies such as focused education and training in penicillin allergy evaluation can address knowledge and confidence barriers reported by frontline clinicians. Other key strategies involve developing a system of champions, improving communications systems, and restructuring the healthcare team. Implementation mapping can provide a powerful multi-method framework to study, design, and customize intervention strategies.

CONCLUSION

Empowering clinicians beyond allergy specialists to conduct penicillin allergy assessments requires designing new workflows and systems and providing additional knowledge to those clinicians.

Randomized Multicenter Trial for the Validation of an Easy-to-Administer Algorithm to Define Penicillin Allergy Status in Sexually Transmitted Infection Clinic Outpatients

BACKGROUND

Approximately 15% of patients in sexually transmitted infection (STI) clinics report penicillin allergies, complicating treatment for syphilis and gonorrhea. Nonetheless, >90% do not have a penicillin allergy when evaluated. We developed and validated an algorithm to define which patients reporting penicillin allergy can be safely treated at STI clinics with these drugs.

METHODS

Randomized controlled trial to assess feasibility and safety of penicillin allergy evaluations in STI clinics. Participants with reported penicillin allergy answered an expert-developed questionnaire to stratify risk. Low-risk participants underwent penicillin skin testing (PST) followed by amoxicillin 250 mg challenge or a graded oral challenge (GOC)-amoxicillin 25 mg followed by 250 mg. Reactions were recorded, and participant/provider surveys were conducted.

RESULTS

Of 284 participants, 72 (25.3%) were deemed high risk and were excluded. Of 206 low-risk participants, 102 (49.5%) underwent PST without reactions and 3 (3%) had mild reactions during the oral challenge. Of 104 (50.5%) participants in the GOC, 95 (91.3%) completed challenges without reaction, 4 (4.2%) had mild symptoms after 25 mg, and 4 (4.2%) after 250-mg doses. Overall, 195 participants (94.7%) successfully completed the study and 11 (5.3%) experienced mild symptoms. Of 14 providers, 12 (85.7%) completed surveys and 11 (93%) agreed on the safety/effectiveness of penicillin allergy assessment in STI clinics.

CONCLUSIONS

An easy-to-administer risk-assessment questionnaire can safely identify patients for penicillin allergy evaluation in STI clinics by PST or GOC, with GOC showing operational feasibility. Using this approach, 67% of participants with reported penicillin allergy could safely receive first-line treatments for gonorrhea or syphilis. Clinical Trials Registration. Clinicaltrials.gov (NCT04620746).

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.

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.

Behavior-change interventions to improve antimicrobial stewardship in human health, animal health, and livestock agriculture: A systematic review

Antimicrobial resistance (AMR) is an economic, food security, and global health threat accelerated by a multitude of factors including the overuse and misuse of antimicrobials in the human health, animal health, and agriculture sectors. Given the rapid emergence and spread of AMR and the relative lack of development of new antimicrobials or alternative therapies, there is a need to develop and implement non-pharmaceutical AMR mitigation policies and interventions that improve antimicrobial stewardship (AMS) practices across all sectors where antimicrobials are used. We conducted a systematic literature review per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to identify peer-reviewed studies that described behavior-change interventions that aimed to improve AMS and/or reduce inappropriate antimicrobial use (AMU) among human health, animal health, and livestock agriculture stakeholders. We identified 301 total publications- 11 in the animal health sector and 290 in the human health sector-and assessed described interventions using metrics across five thematic areas- (1) AMU, (2) adherence to clinical guidelines, (3) AMS, (4) AMR, and (5) clinical outcomes. The lack of studies describing the animal health sector precluded a meta-analysis. Variation across intervention type, study type, and outcome precluded a meta-analysis for studies describing the human health sector; however, a summary descriptive analysis was conducted. Among studies in the human health sector, 35.7% reported significant (p<0.05) pre- to post-intervention decreases in AMU, 73.7% reported significant improvements in adherence of antimicrobial therapies to clinical guidelines, 45% demonstrated significant improvements in AMS practices, 45.5% reported significant decreases in the proportion of isolates that were resistant to antibiotics or the proportion of patients with drug-resistant infections across 17 antimicrobial-organism combinations. Few studies reported significant changes in clinical outcomes. We did not identify any overarching intervention type nor characteristics associated with successful improvement in AMS, AMR, AMU, adherence, nor clinical outcomes.

Penicillin allergy delabeling: Opportunities for implementation and dissemination

Although existing as a safety measure to prevent iatrogenic harm, unconfirmed penicillin allergy labels have a negative impact on personal and public health. One downstream effect of unconfirmed penicillin allergy is the continued emergence and transmission of resistant bacteria and their associated health care costs. Recognizing the consequences of inaccurate penicillin allergy labels, professional and public health organizations have started promoting the adoption of proactive penicillin allergy evaluations, with the ultimate goal of removing the penicillin allergy label when the allergy is disproved, also known as penicillin allergy "delabeling." A penicillin allergy evaluation includes a comprehensive allergy history often followed by drug challenge, sometimes with preceding skin testing. Currently, penicillin allergy delabeling is largely carried out by allergy specialists in outpatient settings. Penicillin allergy delabeling is performed on inpatients, albeit rarely, often at the time of need, as a point-of-care procedure. Access to penicillin allergy evaluation services is limited. Recent studies demonstrate the feasibility of expanding penicillin allergy evaluations and delabeling to internists, pediatricians, emergency medicine physicians, infectious diseases specialists, and clinical pharmacists. However, reducing the impact of mislabeled penicillin allergy will require comprehensive efforts and new investments. In this review, we summarize the current practices of penicillin allergy delabeling and discuss expansion opportunities for penicillin allergy delabeling as quality improvement.

The effectiveness of interventions that support penicillin allergy assessment and delabeling of adult and pediatric patients by nonallergy specialists: a systematic review and meta-analysis

OBJECTIVES

Penicillin allergy records are often incorrect and may result in harm. We aimed to systematically review the effectiveness and safety of nonallergist health care worker delivery of penicillin allergy delabeling.

METHODS

We searched EMBASE/MEDLINE/CINAHL (Ovid), PsycInfo, Web of Science, and Cochrane CENTRAL from inception to January 21, 2022 and unpublished studies and gray literature. The proportion of patients allergic to penicillin delabeled and harmed was calculated using random-effects models.

RESULTS

Overall, 5019 patients were delabeled. Using allergy history alone, 14% (95% confidence interval [CI], 9-21%) of 4350 assessed patients were delabeled without reported harm. Direct drug provocation testing resulted in delabeling in 27% (95% CI, 18-37%) of 4207 assessed patients. Of the 1373 patients tested, 98% were delabeled (95% CI, 97-99%), and nonserious harm was reported in 1% (95% CI, 0-2%). Using skin testing, followed by drug provocation testing, 41% (95% CI, 24-59%) of 2890 assessed patients were delabeled. Of the 1294 tested patients, 95.0% (95% CI, 90-99%) were delabeled, and the reported harm was low (0%; (95% CI 0-1%).

CONCLUSION

Penicillin allergy delabeling by nonallergists is efficacious and safe. The proportion of assessed patients who can be delabeled increases with the complexity of testing method, but substantial numbers can be delabeled without skin testing.

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

Drug hypersensitivity reactions (DHRs) to intravenous drugs can be severe and might leave patients and doctors in a difficult position where an essential treatment or intervention has to be suspended. Even if virtually any intravenous medication can potentially trigger a life-threatening DHR, chemotherapeutics, biologics, and antibiotics are amongst the intravenous drugs most frequently involved in these reactions. Admittedly, suspending such treatments may negatively impact the survival outcomes or the quality of life of affected patients. Delabeling pathways and rapid drug desensitization (RDD) can help reactive patients stay on first-choice therapies instead of turning to less efficacious, less cost-effective, or more toxic alternatives. However, these are high-complexity and high-risk techniques, which usually need expert teams and allergy-specific techniques (skin testing, in vitro testing, drug provocation testing) to ensure safety, an accurate diagnosis, and personalized management. Unfortunately, there are significant inequalities within and among countries in access to allergy departments with the necessary expertise and resources to offer these techniques and tackle these DHRs optimally. The main objective of this consensus document is to create a great benefit for patients worldwide by aiding allergists to expand the scope of their practice and support them with evidence, data, and experience from leading groups from around the globe. This statement of the Drug Hypersensitivity Committee of the World Allergy Organization (WAO) aims to be a comprehensive practical guide on the technical aspects of implementing acute-onset intravenous hypersensitivity delabeling and RDD for a wide range of drugs. Thus, the manuscript does not only focus on clinical pathways. Instead, it also provides guidance on topics usually left unaddressed, namely, internal validation, continuous quality improvement, creating a healthy multidisciplinary environment, and redesigning care (including a specific supplemental section on a real-life example of how to design a dedicated space that can combine basic and complex diagnostic and therapeutic techniques in allergy).

Opportunities for penicillin allergy evaluation in dental clinics

OBJECTIVE

To evaluate opportunities for assessing penicillin allergies among patients presenting to dental clinics.

DESIGN

Retrospective cross-sectional study.

SETTING

VA dental clinics.

PATIENTS

Adult patients with a documented penicillin allergy who received an antibiotic from a dentist between January 1, 2015, and December 31, 2018, were included.

METHODS

Chart reviews were completed on random samples of 100 patients who received a noncephalosporin antibiotic and 200 patients who received a cephalosporin. Each allergy was categorized by severity. These categories were used to determine patient eligibility for 3 testing groups based on peer-reviewed algorithms: (1) no testing, (2) skin testing, and (3) oral test-dose challenge. Descriptive and bivariate statistics were used to compare facility and patient demographics first between true penicillin allergy, pseudo penicillin allergy, and missing allergy documentation, and between those who received a cephalosporin and those who did not at the dental visit.

RESULTS

Overall, 19% lacked documentation of the nature of allergic reaction, 53% were eligible for skin testing, 27% were eligible for an oral test-dose challenge, and 1% were contraindicated from testing. Male patients and African American patients were less likely to receive a cephalosporin.

CONCLUSIONS

Most penicillin-allergic patients in the VA receiving an antibiotic from a dentist are eligible for penicillin skin testing or an oral penicillin challenge. Further research is needed to understand the role of dentists and dental clinics in assessing penicillin allergies.

Is Penicillin Allergy a Risk Factor for Surgical Site Infection After Oral and Maxillofacial Surgery?

PURPOSE

The selection of perioperative antibiotics for prevention of surgical site infection (SSI) is often limited by the presence of a reported penicillin allergy. The purpose of this study was to determine if oral and maxillofacial surgery patients who report allergy to penicillin are at an increased risk of developing SSI.

METHODS

A retrospective cohort study was performed of patients who underwent oral and maxillofacial surgical procedures in the operating room setting at a single institution between 2011 and 2018. The following categories of procedures were investigated: dentoalveolar, orthognathic, orthognathic with third molar extraction, pathology and reconstruction, and temporomandibular joint. The primary predictor and outcome variables were reported penicillin allergy and surgical site infection, respectively. Bivariate and multiple logistic regression analysis were performed. P < .05 was considered to be significant.

RESULTS

The cohort was composed of 2,058 patients of which 318 (15.5%) reported allergy to penicillin. Beta-lactam antibiotics were administered less frequently to penicillin allergic patients perioperatively compared with those without penicillin allergy (7.9 vs 97.1%, P < .001), while clindamycin was more commonly administered (76.4 vs 2.5%, P < .001). Clindamycin was associated with a higher SSI rate compared with beta-lactam antibiotics (5.6 vs 1.4%, P < .001). Penicillin allergy was significantly associated with SSI at an adjusted odds ratio of 2.61 (95% CI 1.51 to 4.49, P = .001). After holding perioperative antibiotic usage equal between the 2 groups, penicillin allergy per se was no longer associated with SSI (P = .901), suggesting that the outcome was mediated by antibiotic selection.

CONCLUSIONS

Penicillin allergy was associated with development of SSI due to receipt of non-beta-lactam antibiotics as perioperative prophylaxis. Formal allergy evaluation should be considered for patients with putative penicillin allergy.

Sexually Transmitted Infections Treatment Guidelines, 2021

These guidelines for the treatment of persons who have or are at risk for sexually transmitted infections (STIs) were updated by CDC after consultation with professionals knowledgeable in the field of STIs who met in Atlanta, Georgia, June 11-14, 2019. The information in this report updates the 2015 guidelines. These guidelines discuss 1) updated recommendations for treatment of Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis; 2) addition of metronidazole to the recommended treatment regimen for pelvic inflammatory disease; 3) alternative treatment options for bacterial vaginosis; 4) management of Mycoplasma genitalium; 5) human papillomavirus vaccine recommendations and counseling messages; 6) expanded risk factors for syphilis testing among pregnant women; 7) one-time testing for hepatitis C infection; 8) evaluation of men who have sex with men after sexual assault; and 9) two-step testing for serologic diagnosis of genital herpes simplex virus. Physicians and other health care providers can use these guidelines to assist in prevention and treatment of STIs.

Overview of Beta-Lactam Allergy and the Role of the Pharmacist in Management

Unverified beta-lactam allergies are a substantial public health problem, as the majority of patients labeled as beta-lactam allergic do not have clinically significant allergies that may hinder the use beta-lactam therapy when indicated. Outdated or inaccurate beta-lactam or penicillin allergies can result in serious consequences, including suboptimal antibiotic therapy, increased risk of adverse effects, and use of broader spectrum antibiotics than indicated, which may contribute to antimicrobial resistance. The purpose of this review is to provide an overview of beta-lactam allergy and highlight the role of pharmacists in managing beta-lactam allergies. Studies have shown that pharmacists can play a vital role in allergy assessment, penicillin skin testing, beta-lactam desensitization, evaluation of beta-lactam cross-reactivity and recommending appropriate antibiotic therapy in patients with beta-lactam allergies.

Description of a pharmacist-managed/administered penicillin allergy skin testing service at a community hospital

PURPOSE

To describe how a pharmacist-managed and pharmacist-administered penicillin allergy skin testing (PAST) service was incorporated into an antimicrobial stewardship program at a community hospital.

METHODS

A pharmacist-managed/administered PAST service was initiated in October 2015. Patients 18 years of age or older were considered for PAST if they had a reported history of a type I or unknown type of allergic reaction to penicillin that occurred more than 5 years previously. Patients with a vague allergy history were considered for PAST if the provider was uncomfortable prescribing a preferred β-lactam out of concern for penicillin allergy. Patients were excluded if they were pregnant, had a history of a non-type I allergic reaction, or recently received antihistamines. The primary outcome was the percentage of patients who underwent PAST and were subsequently transitioned to a preferred β-lactam.

RESULTS

PAST was initiated in 90 patients from October 2015 to December 2019. Eighty-five out of 90 patients (94%) completed PAST. Seventy-six out of 90 patients (84.4%) who underwent PAST were transitioned to a preferred β-lactam. The most commonly administered antibiotics prior to PAST were vancomycin, cefepime, and metronidazole. The most commonly used antibiotics after PAST were penicillin, piperacillin/tazobactam, and ampicillin/sulbactam. Among the 90 patients who underwent PAST, alternative antibiotics were avoided for a total of 1,568 days, with a median of 11 days (interquartile range, 6-18 days) avoided per patient.

CONCLUSION

Incorporating a pharmacist-managed/administered PAST service into a community hospital's antimicrobial stewardship program can improve the utilization of preferred antimicrobial therapy and help avoid use of more toxic, costly antimicrobials.

Penicillin Allergy Delabeling: A Multidisciplinary Opportunity

The penicillin allergy label has been consistently linked with deleterious effects that span the health care spectrum, including suboptimal clinical outcomes, the emergence of bacterial resistance, and increased health care expenditures. These risks have recently motivated professional organizations and public health institutes to advocate for the implementation of penicillin allergy delabeling initiatives; however, the burden of delabeling millions of patients is too expansive for any one discipline to bear alone. This review presents the unique perspectives and roles of various stakeholder groups involved in penicillin allergy diagnosis, assessment, and delabeling; we emphasize opportunities, barriers, and promising areas of innovation. We summarize penicillin allergy methods and tools that have proven successful in delabeling efforts. A multidisciplinary approach to delabeling patients with reported penicillin allergy, bolstered by evidence-based clinical practices, is recommended to reduce the risks that associate with the penicillin allergy label.

Penicillin Allergy Testing Is Cost-Saving: An Economic Evaluation Study

BACKGROUND

Having a penicillin allergy label is associated with the use of less appropriate and more expensive antibiotics and increased healthcare utilization. Penicillin allergy testing results in delabeling most allergy claimants and may be cost-saving. This study aimed to project whether penicillin allergy testing in patients reporting a penicillin allergy is cost-saving.

METHODS

In this economic evaluation study, we built decision models to project the economic impact of 2 strategies for a patient with a penicillin allergy label: (1) perform diagnostic testing (drug challenges, with or without skin tests); and (2) do not perform diagnostic testing. The health service perspective was adopted, considering costs with penicillin allergy tests, and with hospital bed-days/outpatient visits, antibiotic use, and diagnostic testing. Twenty-four base case decision models were built, accounting for differences in the diagnostic workup, setting (inpatient vs outpatient) and geographic region. Uncertainty was explored via probabilistic sensitivity analyses.

RESULTS

Penicillin allergy testing was cost-saving in all decision models built. For models assessing the performance of both skin tests and drug challenges, allergy testing resulted in average savings (in United States [US] dollars) of $657 for inpatients (US: $1444; Europe: $489) and $2746 for outpatients (US: $256; Europe: $6045). 75% of simulations obtained through probabilistic sensitivity analysis identified testing as the less costly option.

CONCLUSIONS

Penicillin allergy testing was projected to be cost-saving across different scenarios. These results are devised to inform guidelines, supporting the adoption of policies promoting widespread testing of patients with a penicillin allergy label.

Impact of a Comprehensive Antimicrobial Stewardship Program on Institutional Burden of Antimicrobial Resistance: A 14-Year Controlled Interrupted Time-series Study

BACKGROUND

Antimicrobial resistance (AMR) constitutes an international public health threat widely believed to result from excessive antimicrobial use (AMU). Numerous authorities have recommended antimicrobial stewardship programs (ASPs) to curb the selection of AMR, but there is a lack of data confirming this benefit.

METHODS

A controlled interrupted time-series study spanning 14 years was performed to assess impact of a comprehensive hospital-based ASP that included pharmacist-led audit and feedback on institutional AMR. Patient-level microbiologic and AMU data were obtained from October 2002 to September 2016. Poisson regression models were used to identify changes in the incidence and trend of hospital-acquired (HA) antibiotic-resistant organisms (AROs) and multidrug-resistant organisms (MDROs). Changes in community-acquired (CA)-ARO, CA-MDRO, and inpatient AMU were assessed as controls and process outcomes.

RESULTS

Statistically significant shifts in AMU, HA-ARO, and HA-MDRO trends coinciding with ASP implementation were observed, corresponding with a 9% reduction in HA-ARO burden (incidence rate ratio [IRR], 0.91 [95% confidence interval {CI}, .83-.99]; P = .03) and a 13% reduction in HA-MDRO burden (IRR, 0.87 [95% CI, .73-1.04]; P = .13) in the intervention period. In contrast, CA-ARO and CA-MDRO incidence continued to rise, with 40% (IRR, 1.40 [95% CI, 1.28-1.54]; P < .0001) and 68% (IRR, 1.68 [95% CI, 1.57-1.82]; P < .0001) increases in burden found, respectively.

CONCLUSIONS

Implementation of a comprehensive ASP resulting in reduced AMU was associated with a significant reduction in institutional AMR, even though community AMR increased during the same period. These results confirm that ASPs play an important role in the fight against AMR.

Resources Assessment for Penicillin Allergy Testing Performed by Pharmacists at the Patient's Bedside

Background:

False penicillin allergies lead to increased antimicrobial resistance, adverse effects, and health care costs by promoting the use of broad-spectrum antibiotics. The Infectious Diseases Society of America recommends the implementation of allergy testing.

Objectives:

The primary objective of this research was to estimate the number of pharmacist full-time equivalents (FTEs) required for an intervention aimed at determining penicillin allergy in hospitalized patients. Acceptance of pharmacists’ suggestions on antibiotic therapy are described.

Methods:

A quasi-experimental study was conducted in a 712-bed university hospital involving hospitalized patients with a suspected penicillin allergy and an infection treatable with penicillin. The time required for the intervention, which included a questionnaire, penicillin allergy testing (skin-prick test, intradermal injection, and oral provocation test), and recommendations on antibiotic therapy were measured to calculate the number of pharmacist FTEs.

Results:

A total of 55 patients were included. Scarification allergy testing was performed on 37, intradermal allergy test on 33, and oral provocation test on 26 patients. The intervention ruled out penicillin allergy in 26 patients, with no serious adverse effects. The intervention was associated with a median weekly pharmacist FTE of 0.15 (interquartile range = 0.12-0.25). The acceptance of pharmacists’ suggestions was high and led to 9 patients being switched to an antibiotic with a narrower spectrum of activity.

Conclusions and Relevance:

This study describes penicillin allergy testing and the number of median weekly hospital pharmacist FTEs required, which was approximately 0.15. These data may aid in the implementation of this safe intervention that promotes narrower-spectrum antibiotherapy.

The challenge of de-labeling penicillin allergy

BACKGROUND

Even though 8%-25% of most populations studied globally are labeled as penicillin allergic, most diagnoses of penicillin allergy are made in childhood and relate to events that are either not allergic in nature, are low risk for immediate hypersensitivity, or are a potential true allergy that has waned over time. Penicillin allergy labels directly impact antimicrobial stewardship by leading to use of less effective and broader spectrum antimicrobials and are associated with antimicrobial resistance. They may also delay appropriate antimicrobial therapy and lead to increased risk of specific adverse healthcare outcomes. Operationalizing penicillin allergy de-labeling into a new arm of antimicrobial stewardship programs (ASPs) has become an increasing global focus.

METHODS

We performed an evidence-based narrative review of the literature of penicillin allergy label carriage, the adverse effects of penicillin allergy labels, and current approaches and barriers to penicillin allergy de-labeling. Over the period 1928-2018 in Pubmed and Medline, search terms used included "penicillin allergy" or "penicillin hypersensitivity" alone or in combination with "adverse events," "testing," "evaluation," "effects," "label," "de-labeling," "prick or epicutaneous," and "intradermal" skin testing, "oral challenge or provocation," "cross-reactivity," and "antimicrobial stewardship".

RESULTS

Penicillin allergy labels are highly prevalent, largely inaccurate and their carriage may lead to unnecessary treatment and inferior outcomes with alternative agents as well as adverse public health outcomes such as antibiotic resistance.

CONCLUSIONS

Operationalizing penicillin allergy de-labeling as an aspect of ASP has become an increasing global focus. There is a need for validated approaches that optimally combine the use of history and ingestion challenge with or without proceeding formal skin testing to tackle penicillin allergy efficiently within complex healthcare systems. At the same time, there is great promise for penicillin allergy evaluation and de-labeling as an individual and public health strategy to reduce adverse healthcare outcomes, improve antimicrobial stewardship, and decrease healthcare costs.

Self-reported beta-lactam allergy and the risk of surgical site infection: A retrospective cohort study

OBJECTIVE

To assess whether a self-reported β-lactam allergy is associated with an increased risk of surgical site infection (SSI) across a broad range of procedures and to determine whether this association is mediated by the receipt of an alternate antibiotic to cefazolin.

DESIGN

Retrospective cohort study.

PARTICIPANTS

Surgical procedures sampled by an institutional National Surgical Quality Improvement Program database over an 18-month period (January 2017 to June 2018) from 7 surgical specialties.

SETTING

Tertiary-care academic hospital.

RESULTS

Of the 3,589 surgical procedures included in the study, 369 (10.3%) were performed in patients with a reported β-lactam allergy. Those with a reported β-lactam allergy were significantly less likely to receive cefazolin (38.8% vs 95.5%) or metronidazole (20.3% vs 26.1%) and were more likely to receive clindamycin (52.0% vs 0.2%), gentamicin (3.5% vs 0%), or vancomycin (2.2% vs 0.1%) than those without allergy. An SSI occurred in 154 of 3,220 procedures (4.8%) in patients without reported allergy and 27 of 369 (7.3%) with reported allergy. In the multivariable regression model, a reported β-lactam allergy was associated with a statistically significant increase in SSI risk (adjusted odds ratio [aOR], 1.61; 95% confidence interval [CI], 1.04-2.51; P = .03). This effect was completely mediated by receipt of an alternate antibiotic to cefazolin (indirect effect aOR, 1.68; 95% CI, 1.17-2.34; P = .005).

CONCLUSIONS

Self-reported β-lactam allergy was associated with an increased SSI risk mediated through receipt of alternate antibiotic prophylaxis. Safely increasing use of cefazolin prophylaxis in patients with reported β-lactam allergy can potentially lower the risk of SSIs.

Is a Reported Penicillin Allergy Sufficient Grounds to Forgo the Multidimensional Antimicrobial Benefits of β-Lactam Antibiotics?

The majority of patients with reported penicillin allergy are not allergic when tested or challenged. Penicillin allergy testing has been shown to significantly reduce annual healthcare expenditures. Data have emerged showing β-lactams have multidimensional antibacterial effects in vivo, far beyond what is appreciated in standard bacteriological susceptibility testing media. These include enhancing bacterial killing by the innate immune system. Supporting the clinical relevance of these secondary underappreciated effects are recent clinical and pharmacoeconomic analyses that show worse outcomes in patients with reported penicillin allergies who receive non-β-lactam antibiotics when compared to their non-penicillin-allergic counterparts. This is particularly relevant in the treatment of Staphylococcus aureus bacteremia. This article reviews the tremendous advantages offered by β-lactam therapy and makes a strong case that the debunking of false penicillin allergies through a detailed allergy history and penicillin allergy testing should be a vital component of antimicrobial stewardship practices.

Pharmacist-driven penicillin skin testing service for adults prescribed nonpreferred antibiotics in a community hospital

PURPOSE

Results of a study evaluating the implementation and impact of a pharmacist-driven penicillin skin testing (PST) service for patients prescribed alternative antibiotics in the community hospital setting are reported.

METHODS

A prospective pilot service in which patients with a documented penicillin allergy (type I, immunoglobulin E [IgE]-mediated) who were prescribed alternative antibiotics received PST by a trained pharmacist was implemented; if test results were negative, the allergy was de-labeled from their electronic medical record. The primary objective was the percentage of patients switched to first-line antibiotics. Secondary objectives included length of stay (LOS) and inpatient antimicrobial costs to the health system.

RESULTS

Twenty-two patients were proactively identified and received PST by a pharmacist. Of those tested, all were negative, with no type I (IgE-mediated) hypersensitivity reactions to the test itself or to the beta-lactam antibiotic administered thereafter; 68.2% (15/22) were successfully transitioned to a beta-lactam after PST. As a result, a decrease in the use of fluoroquinolones and vancomycin and an increase in use of narrow penicillin-based antibiotics and first- and second-generation cephalosporins were observed. The mean ± S.D. LOS per patient was 7.41 ± 6.1 days, and the total cost of inpatient antimicrobial therapy to the health system was $1,698.88.

CONCLUSION

A pharmacist-driven PST service was successfully implemented in a community hospital setting.

Penicillin Allergy Skin Testing in the Inpatient Setting

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

A Baker's Dozen of Top Antimicrobial Stewardship Intervention Publications in 2017

With an increasing number of antimicrobial stewardship-related articles published each year, attempting to stay current is challenging. The Southeastern Research Group Endeavor (SERGE-45) identified antimicrobial stewardship-related peer-reviewed literature that detailed an "actionable" intervention for 2017. The top 13 publications were selected using a modified Delphi technique. These manuscripts were reviewed to highlight the "actionable" intervention used by antimicrobial stewardship programs to provide key stewardship literature for training and teaching and identify potential intervention opportunities within their institutions.

Outcomes from an inpatient beta-lactam allergy guideline across a large US health system

Objective:

To assess the safety of, and subsequent allergy documentation associated with, an antimicrobial stewardship intervention consisting of test-dose challenge procedures prompted by an electronic guideline for hospitalized patients with reported β-lactam allergies.

Design:

Retrospective cohort study.

Setting:

Large healthcare system consisting of 2 academic and 3 community acute-care hospitals between April 2016 and December 2017.

Methods:

We evaluated β-lactam antibiotic test-dose outcomes, including adverse drug reactions (ADRs), hypersensitivity reactions (HSRs), and electronic health record (EHR) allergy record updates. HSR predictors were examined using a multivariable logistic regression model. Modification of the EHR allergy record after test doses considered relevant allergy entries added, deleted, and/or specified.

Results:

We identified 1,046 test-doses: 809 (77%) to cephalosporins, 148 (14%) to penicillins, and 89 (9%) to carbapenems. Overall, 78 patients (7.5%; 95% confidence interval [CI], 5.9%–9.2%) had signs or symptoms of an ADR, and 40 (3.8%; 95% CI, 2.8%–5.2%) had confirmed HSRs. Most HSRs occurred at the second (ie, full-dose) step (68%) and required no treatment beyond drug discontinuation (58%); 3 HSR patients were treated with intramuscular epinephrine. Reported cephalosporin allergy history was associated with an increased odds of HSR (odds ratio [OR], 2.96; 95% CI, 1.34–6.58). Allergies were updated for 474 patients (45%), with records specified (82%), deleted (16%), and added (8%).

Conclusion:

This antimicrobial stewardship intervention using β-lactam test-dose procedures was safe. Overall, 3.8% of patients with β-lactam allergy histories had an HSR; cephalosporin allergy histories conferred a 3-fold increased risk. Encouraging EHR documentation might improve this safe, effective, and practical acute-care antibiotic stewardship tool.

Pharmacy-Led β-Lactam Allergy Interview (BLAI) Reduces Duration of Fluoroquinolones Within a Community Hospital

BACKGROUND

Patients with reported β-lactam allergies often receive broad-spectrum antimicrobials and have been shown to experience a variety of negative health consequences, such as increased mortality, costs, readmission, and adverse reactions. Current literature focuses on β-lactam allergy skin testing but lacks evidence on β-lactam allergy interviews (BLAI) when skin testing is unavailable.

OBJECTIVE

This study aimed to test the impact of a pharmacy-led BLAI on duration of fluoroquinolones at a community hospital.

METHODS

A quasi-experimental design with a prospective cohort design and historical control group was used to assess patients with reported penicillin (PCN) allergies in a community hospital. The primary outcome was duration of fluoroquinolones before and after implementation of BLAI. Secondary outcomes included length of stay (LOS), percentage of patients switched to a β-lactam antibiotic, percentage of antimicrobial stewardship recommendations made/accepted, and discrepancies between allergy in medical record and interview-reported allergy. Nonparametric continuous data and medians were evaluated by Mann-Whitney U.

RESULTS

A total of 80 patients were included in the study (43 in the control group and 37 in the prospective group). Fluoroquinolone duration was reduced after the implementation of BLAI (3.7 vs 2.7 days, P = 0.027). In all, 49% of patients in the prospective group were switched to a β-lactam antibiotic after BLAI, with no allergic reactions, adverse effects, or impact on LOS. Conclusion and Relevance: BLAI resulted in a significant reduction in fluoroquinolone duration in patients with PCN allergies and may represent a safe and effective option for institutions lacking skin-testing capabilities.

Evaluation and Management of Penicillin Allergy: A Review

IMPORTANCE

β-Lactam antibiotics are among the safest and most effective antibiotics. Many patients report allergies to these drugs that limit their use, resulting in the use of broad-spectrum antibiotics that increase the risk for antimicrobial resistance and adverse events.

OBSERVATIONS

Approximately 10% of the US population has reported allergies to the β-lactam agent penicillin, with higher rates reported by older and hospitalized patients. Although many patients report that they are allergic to penicillin, clinically significant IgE-mediated or T lymphocyte-mediated penicillin hypersensitivity is uncommon (<5%). Currently, the rate of IgE-mediated penicillin allergies is decreasing, potentially due to a decreased use of parenteral penicillins, and because severe anaphylactic reactions to oral amoxicillin are rare. IgE-mediated penicillin allergy wanes over time, with 80% of patients becoming tolerant after a decade. Cross-reactivity between penicillin and cephalosporin drugs occurs in about 2% of cases, less than the 8% reported previously. Some patients have a medical history that suggests they are at a low risk for developing an allergic reaction to penicillin. Low-risk histories include patients having isolated nonallergic symptoms, such as gastrointestinal symptoms, or patients solely with a family history of a penicillin allergy, symptoms of pruritus without rash, or remote (>10 years) unknown reactions without features suggestive of an IgE-mediated reaction. A moderate-risk history includes urticaria or other pruritic rashes and reactions with features of IgE-mediated reactions. A high-risk history includes patients who have had anaphylaxis, positive penicillin skin testing, recurrent penicillin reactions, or hypersensitivities to multiple β-lactam antibiotics. The goals of antimicrobial stewardship are undermined when reported allergy to penicillin leads to the use of broad-spectrum antibiotics that increase the risk for antimicrobial resistance, including increased risk of methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus. Broad-spectrum antimicrobial agents also increase the risk of developing Clostridium difficile (also known as Clostridioides difficile) infection. Direct amoxicillin challenge is appropriate for patients with low-risk allergy histories. Moderate-risk patients can be evaluated with penicillin skin testing, which carries a negative predictive value that exceeds 95% and approaches 100% when combined with amoxicillin challenge. Clinicians performing penicillin allergy evaluation need to identify what methods are supported by their available resources.

CONCLUSIONS AND RELEVANCE

Many patients report they are allergic to penicillin but few have clinically significant reactions. Evaluation of penicillin allergy before deciding not to use penicillin or other β-lactam antibiotics is an important tool for antimicrobial stewardship.

The Clinical and Financial Impact of a Pharmacist-Driven Penicillin Skin Testing Program on Antimicrobial Stewardship Practices

Purpose: Pharmacist-led penicillin skin testing (PST) was incorporated into antimicrobial stewardship at a community hospital to increase use of optimal antimicrobial therapy, reduce use of broad-spectrum agents, and reduce antimicrobial therapy-related costs. Methods: A clinical decision support software alert identified qualifying patients with penicillin allergies. Patients receiving a nonoptimal antimicrobial agent were prioritized for PST. Patients were excluded if they reported a history of extreme hypersensitivity to a penicillin agent, such as Stevens-Johnson syndrome, toxic epidermal necrolysis, or mucocutaneous eruption with epidermal detachment. Pediatric patients less than 18 years old and pregnant patients were excluded. Data collected for each patient included the medication that precipitated the reaction; reaction type; age when the reaction occurred; current antibiotic therapy; indication for therapy; preferred antimicrobial agent; days of therapy on each agent used; positive, negative, or ambiguous PST result; recent antihistamine use; and any adverse events that occurred. Outcomes of the PST results, pharmacist interventions made after PST, and resulting cost savings to patients were all reported. Results: Among 31 patients tested, 27 were negative for penicillin allergy, 1 was positive for penicillin allergy, and 3 yielded an indeterminate test. Pharmacist recommendation to change therapy based on PST results was accepted in 13 of 15 patients where recommendations were made. Cost savings in antimicrobial therapy alone for patients who received PST was US $74.75 per day. Conclusion: Pharmacist-driven PST provided opportunities to clarify allergies, optimize antimicrobial therapy, and save antimicrobial therapy-related costs to patients.

Penicillin allergy de-labelling ahead of elective surgery: feasibility and barriers

BACKGROUND

Around 10-15% of the in-patient population carry unsubstantiated 'penicillin allergy' labels, the majority incorrect when tested. These labels are associated with harm from use of broad-spectrum non-penicillin antibiotics. Current testing guidelines incorporate both skin and challenge tests; this is prohibitively expensive and time-consuming to deliver on a large scale. We aimed to establish the feasibility of a rapid access de-labelling pathway for surgical patients, using direct oral challenge.

METHODS

'Penicillin allergic' patients, recruited from a surgical pre-assessment clinic, were risk-stratified using a screening questionnaire. Patients at low risk of true, immunoglobulin E (IgE)-mediated allergy were offered direct oral challenge using incremental amoxicillin to a total dose of 500 mg. A 3-day course was completed at home. De-labelled patients were followed up to determine antibiotic use in surgery, and attitudes towards de-labelling were explored.

RESULTS

Of 219 patients screened, 74 were eligible for inclusion and offered testing. We subsequently tested 56 patients; 55 were de-labelled. None had a serious reaction to the supervised challenge, or thereafter. On follow-up, 17 of 19 patients received appropriate antimicrobial prophylaxis during surgery. Only three of 33 de-labelled patients would have been happy for the label to be removed without prior specialist testing.

CONCLUSION

Rapid access de-labelling, using direct oral challenge in appropriately risk-stratified patients, can be incorporated into the existing surgical care pathway. This provides immediate and potential long-term benefit for patients. Interest in testing is high among patients, and clinicians appear to follow clinic recommendations. Patients are unlikely to accept removal of their allergy label on the basis of history alone.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: AN17/92982.

The Current State of Antimicrobial Stewardship: Challenges, Successes, and Future Directions

PURPOSE OF REVIEW

The aim of this study is to examine the current state of the field of antimicrobial stewardship (AS) by highlighting key challenges and successes, as well as exciting future directions.

RECENT FINDINGS

AS mandates from the Centers for Medicare and Medicaid (CMS) and the Joint Commission (TJC) will stimulate increased compliance with current AS standards, but overall compliance is currently poor. Key challenges to progress in the field of AS include insufficient workforce and monetary resources, poorly defined AS metrics, and much needed expansion beyond the inpatient hospital setting. Despite these challenges, massive progress has been made in the last two and a half decades since the field of AS emerged. AS metrics are rapidly evolving and transforming the way antimicrobial stewardship programs (ASPs) measure success. Rapid diagnostics and diagnostic test stewardship are proving to be extremely effective when coupled with an ASP. Telehealth may improve access to ASP expertise in resource poor settings, and the role of bedside nurses as ASP team members has the potential to greatly augment ASP efforts. Allergy testing as an ASP strategy remains largely underutilized. ASPs have made significant gains in the battle against antimicrobial resistance (AR), but considerable advancement is still needed. Awareness of current challenges is critical to ensure progress in the field. The field of AS is expanding and transforming rapidly through integration, technology, and improved processes.

Influence of Reported Penicillin Allergy on Mortality in MSSA Bacteremia

Background

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

Methods

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

Results

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

Conclusions

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

Confronting the Challenge of Beta-Lactam Allergies: A Quasi-Experimental Study Assessing Impact of Pharmacy-Led Interventions

OBJECTIVE

To improve allergy history documentation and increase the use of beta-lactams when appropriate in patients with a reported beta-lactam allergy.

METHODS

This pre-post study was conducted at a 167-bed tertiary care community hospital and evaluated multidisciplinary interventions on allergy documentation and antibiotic selection. Interventions included education, creation of local practice guidelines, and modified practices for pharmacists and pharmacy technicians. Inpatients with a reported beta-lactam allergy receiving at least 1 antibiotic for >24 hours were included; first admissions were assessed. Primary outcomes were documentation of reaction type and percentage of patients receiving non-beta-lactam therapy. Secondary outcomes included documentation of previously tolerated beta-lactams, modification of non-beta-lactam therapy, discharge antibiotics, and adverse reactions.

RESULTS

A total of 179 patients were included, 91 preintervention and 88 postintervention. No significant differences were observed between the before versus after groups in the percentage of patients with documentation of reaction type (90.1% vs 89.8%, P = .940) or the overall percentage of patients receiving non-beta-lactams (86.8% vs 84.1%, P = .605). However, significantly more patients in the after phase had documentation of previously tolerated beta-lactams (8.8% vs 28.4%, P = .001), and among patients receiving a non-beta-lactam, a greater percentage was subsequently switched to a beta-lactam (11.4% vs 25.7%, P = .022). One allergic reaction was documented during the study, which occurred in the before phase.

CONCLUSION

Multidisciplinary education and local guideline implementation led by pharmacists may improve allergy documentation and antibiotic selection in patients with reported beta-lactam allergies.