Penicillin and beta-lactam allergy: epidemiology and diagnosis

Testing Strategies and Predictors for Evaluating Immediate and Delayed Reactions to Cephalosporins

BACKGROUND

Although 1% to 2% of the general population carries a cephalosporin allergy label (CAL), we lack validated testing strategies and predictors of true allergy.

OBJECTIVE

To identify cross-reactivity patterns and predictors of skin test positive (STP) in geographically disparate patients with a CAL.

METHODS

A total of 780 adult patients labeled with a CAL or penicillin allergy label (PAL) with unknown tolerance of cephalosporins identified from the Austin Hospital (Melbourne, Australia) (n = 410) and Vanderbilt University Medical Center (Nashville, TN) (n = 370) between 2014 and 2018 underwent a standardized skin testing.

RESULTS

Of 328 patients with a CAL, 29 (8.8%) tested STP to ≥1 cephalosporin(s). There were no cefazolin or ceftriaxone STP, 0 of 452 (0%), in patients with a PAL only. Of 328 patients with a CAL, 16 (4.8%) were ampicillin STP. Eleven of 16 of these patients had an initial allergy label to cephalexin. Twenty of 29 cephalosporin STP patients demonstrated tolerance to a cephalosporin with a different R1 side chain, and 8 of 14 ampicillin STP patients demonstrated tolerance to ≥1 non-amino R1 group cephalosporin. Eleven of 13 patients STP to cefazolin were skin and ingestion challenge negative to all other penicillins and cephalosporins predicted by its distinct R1/R2 groups. Seven of 15 ceftriaxone STP patients demonstrated cross-reactivity with R1-similar cephalosporins. Time since the original reaction predicted STP testing to both penicillins, adjusted odds ratio (aOR) per year 0.93 (95% confidence interval [CI]: 0.90, 0.97), and cephalosporins, aOR per year 0.71 (95% CI: 0.56, 0.90).

CONCLUSIONS

Cephalosporin cross-reactivity is based on shared R1 groupings. Increasing time since the original reaction and the presence of a PAL with unknown cephalosporin tolerance predict a lower likelihood of cephalosporin STP.

Antibiotic allergy labels and optimal antimicrobial stewardship

BACKGROUND

Although common, antimicrobial allergy labels (AAL) rarely reflect immunologically-mediated hypersensitivity and can lead to poorer outcomes from alternative antimicrobial agents. Antimicrobial stewardship programs are ideally placed to assess AAL early as a means of improving antimicrobial use.

OBJECTIVES

To quantify the prevalence of AAL in patients referred for antimicrobial stewardship review and assess their impact on antibiotic prescribing, patient mortality, hospital length of stay, readmission, and rates of multidrug-resistant infections.

METHODS

We conducted a retrospective analysis of adult patients referred for inpatient antimicrobial prospective audit and feedback rounds (PAFR) via an electronic referral system (eReferrals) over a 12-month period in 2015. Outcome data was collected for a period of 36 months following the initial review.

RESULTS

Of the 639 patient records reviewed, 630 met inclusion criteria; 103 (16%) had an AAL, of which 82 (13%) had reported allergies to β-lactam antibiotics. Those with AAL were significantly less likely to be receiving guideline-recommended antimicrobial therapy (50% versus 64%, p=0.0311), however there were no significant difference in mortality, hospital length of stay, readmission or increased incidence of multidrug-resistant infections.

CONCLUSIONS

Our cohort demonstrated that AAL was associated with reduced adherence to antibiotic guidelines. The lack of association with adverse outcomes may reflect limitations within the study including retrospective cohort study numbers and observational nature, further skewed by high rates of poor documentation. A clear opportunity exists for antimicrobial stewardship programs to incorporate allergy assessment, delabelling, challenge and referral into these rounds. This article is protected by copyright. All rights reserved.

Assessing mortality outcomes of beta-lactam-allergic patients presenting with sepsis

OBJECTIVE

To determine the impact of reported beta-lactam allergies on in-hospital mortality and other clinical outcomes in patients who presented with severe sepsis or septic shock.

METHODS

This single-center, retrospective cohort study was performed at a 35-bed emergency department in central Kentucky. Patients presenting with sepsis, aged 18years or older, were identified between October 2016 and June 2017.

RESULTS

438 patients with severe sepsis and/or septic shock were identified. Rates of the combined endpoint of in-hospital mortality or transfer to hospice were similar in patients with a beta-lactam allergy (7.2%) versus those with no reported beta-lactam allergy (10.4%) (p=0.41). Time to initiation of antibiotic therapy was slightly longer in the beta-lactam allergic group (2.2h) versus those with no reported beta-lactam allergy (2.15h), but the difference was not statistically significant (p=0.993). Patients were 20.9% more likely to receive an appropriate empiric antibiotic, based off of retrospective culture review, if they did not report a beta-lactam allergy (p=0.009). This led to a delay in effective therapy of 1.59h in the reported beta-lactam allergy arm (p=0.037).

CONCLUSIONS

Adequate documentation of beta-lactam allergies is vital to ensure timely and appropriate treatment in patients presenting with severe sepsis and septic shock. Choosing alternative treatment options results in increased time to effective antibiotics, reduced likelihood of covering cultures with first antibiotic, and increased total hospital and variable direct cost.

Susceptibility-guided therapy for Helicobacter pylori-infected penicillin-allergic patients: A prospective clinical trial of first-line and rescue therapies

BACKGROUND

Helicobacter pylori (H pylori) treatment remains a challenge for penicillin-allergic patients.

AIM

To evaluate the efficacy and tolerability of susceptibility-guided first-line and rescue treatment in H pylori-infected penicillin-allergic patients.

METHODS

Consecutive H pylori-infected patients with penicillin allergy received a 14-day triple or quadruple therapy based on susceptibility to clarithromycin, levofloxacin, and metronidazole. All received esomeprazole 20 mg twice a day. Metronidazole-susceptible infections received metronidazole plus clarithromycin or levofloxacin triple therapy if susceptible. Clarithromycin- and levofloxacin-resistant infections received metronidazole plus tetracycline triple therapy. Metronidazole-resistant infections received a bismuth-high-dose metronidazole plus clarithromycin or levofloxacin quadruple therapy. Triple-resistant infections received classical bismuth quadruple therapy with high-dose metronidazole. Antimicrobial susceptibility was assessed using the E test method.

RESULTS

112 patients were entered (34.8% men, average 47.1 years). Infections in 83.8% (31/37) of treatment-naive subjects and 12.0% (9/75) (P < .001) receiving rescue treatment were susceptible to at least one of the three tested antibiotics. Overall, susceptibility-guided therapy achieved eradication rates of 92.9% (104/112, 95% CI 88.1%-97.7%) by intent-to-treat analysis and 99% (100/101, 95% CI 97.1%-100%) by per-protocol analysis. All regimens achieved eradication rates greater than 90% (P = .327) in the PP populations. Adverse events were relatively frequent; however, compliance remained high.

CONCLUSION

Susceptibility-guided therapy proved highly effective for penicillin-allergic patients. When available and proven locally effective, the alternative was empiric classical bismuth quadruple therapy. This trial is registered with ClinicalTrials.gov as NCT03708848.

Helicobacter pylori first-line and rescue treatments in patients allergic to penicillin: Experience from the European Registry on H pylori management (Hp-EuReg)

BACKGROUND

Experience in Helicobacter pylori eradication treatment of patients allergic to penicillin is very scarce. A triple combination with a PPI, clarithromycin (C), and metronidazole (M) is often prescribed as the first option, although more recently the use of a quadruple therapy with PPI, bismuth (B), tetracycline (T), and M has been recommended.

AIM

To evaluate the efficacy and safety of first-line and rescue treatments in patients allergic to penicillin in the "European Registry of H pylori management" (Hp-EuReg).

METHODS

A systematic prospective registry of the clinical practice of European gastroenterologists (27 countries, 300 investigators) on the management of H pylori infection. An e-CRF was created on AEG-REDCap. Patients with penicillin allergy were analyzed until June 2019.

RESULTS

One-thousand eighty-four patients allergic to penicillin were analyzed. The most frequently prescribed first-line treatments were as follows: PPI + C + M (n = 285) and PPI + B + T + M (classic or Pylera^® ; n = 250). In first line, the efficacy of PPI + C + M was 69%, while PPI + B + T + M reached 91% (P < .001). In second line, after the failure of PPI + C + M, two rescue options showed similar efficacy: PPI + B + T + M (78%) and PPI + C + levofloxacin (L) (71%) (P > .05). In third line, after the failure of PPI + C + M and PPI + C + L, PPI + B + T + M was successful in 75% of cases.

CONCLUSION

In patients allergic to penicillin, a triple combination with PPI + C + M should not be generally recommended as a first-line treatment, while a quadruple regimen with PPI + B + T + M seems to be a better option. As a rescue treatment, this quadruple regimen (if not previously prescribed) or a triple regimen with PPI + C + L could be used but achieved suboptimal (<80%) results.

Guideline on diagnostic procedures for suspected hypersensitivity to beta-lactam antibiotics: Guideline of the German Society for Allergology and Clinical Immunology (DGAKI) in collaboration with the German Society of Allergology (AeDA), German Society for Pediatric Allergology and Environmental Medicine (GPA), the German Contact Dermatitis Research Group (DKG), the Austrian Society for Allergology and Immunology (ÖGAI), and the Paul-Ehrlich Society for Chemotherapy (PEG)

This guideline on diagnostic procedures for suspected beta-lactam antibiotic (BLA) hypersensitivity was written by the German and Austrian professional associations for allergology, and the Paul-Ehrlich Society for Chemotherapy in a consensus procedure according to the criteria of the German Association of Scientific Medical Societies. BLA such as penicillins and cephalosporins represent the drug group that most frequently triggers drug allergies. However, the frequency of reports of suspected allergy in patient histories clearly exceeds the number of confirmed cases. The large number of suspected BLA allergies has a significant impact on, e.g., the quality of treatment received by the individual patient and the costs to society as a whole. Allergies to BLA are based on different immunological mechanisms and often manifest as maculopapular exanthema, as well as anaphylaxis; and there are also a number of less frequent special clinical manifestations of drug allergic reactions. All BLA have a beta-lactam ring. BLA are categorized into different classes: penicillins, cephalosporins, carbapenems, monobactams, and beta-lactamase inhibitors with different chemical structures. Knowledge of possible cross-reactivity is of considerable clinical significance. Whereas allergy to the common beta-lactam ring occurs in only a small percentage of all BLA allergic patients, cross-reactivity due to side chain similarities, such as aminopenicillins and aminocephalosporins, and even methoxyimino cephalosporins, are more common. However, the overall picture is complex and its elucidation may require further research. Diagnostic procedures used in BLA allergy are usually made up of four components: patient history, laboratory diagnostics, skin testing (which is particularly important), and drug provocation testing. The diagnostic approach - even in cases where the need to administer a BLA is acute - is guided by patient history and risk - benefit ratio in the individual case. Here again, further studies are required to extend the present state of knowledge. Performing allergy testing for suspected BLA hypersensitivity is urgently recommended not only in the interests of providing the patient with good medical care, but also due to the immense impact of putative BLA allergies on society as a whole.

A Practical Guide for Managing Antibiotic Allergies in the Emergency Department

Up to 30% of patients report at least one antibiotic allergy, but oftentimes these antibiotic allergies are misdiagnosed. In fact, of the 10% of patients reporting penicillin allergies, 90%-98% are not truly allergic. In an era of increasing antibiotic resistance coupled with a limited number of new antibiotics, evaluating antibiotic allergies is critical in providing optimal patient care. Differentiating adverse drug reactions from antibiotic allergies may seem like a daunting task for clinicians and providers, especially in the emergency department, where decisions are made quickly. However, a systemic approach, including medical record review coupled with patient and/or family interview, is vital in managing patients with antibiotic allergies. Inappropriate, alternative antibiotics are frequently chosen due to patient allergies, and data suggest higher rates of broad-spectrum antibiotic use, antibiotic resistance, and poor outcomes as a result. Herein, we review antibiotic selection in patients reporting antibiotic allergies in the emergency department.

A Closer Look at Penicillin Allergy History: Systematic Review and Meta-Analysis of Tolerance to Drug Challenge

BACKGROUND

True allergy to penicillin is rare, despite the high frequency with which it is reported. While most patients reporting penicillin allergy are not prone to anaphylaxis, it is not currently known what percentage of these patients will tolerate dose challenges of penicillin-based antibiotics. This review aims to determine the rate of tolerance in patients reporting penicillin allergy when challenged with penicillin-based antibiotics.

METHODS

We searched MedLine, Embase, and Cochrane Library for publications with English language translations between the years 2000 and 2017. We included randomized controlled trials, quasi-experimental, and observational studies of participants reporting penicillin allergy who received at least one systemic dose of a penicillin in the form of a drug challenge. At least 2 independent reviewers extracted data from included studies and assessed the quality of each included study. To generate primary outcome data, we calculated a summary estimate rate of penicillin tolerance from a pooled proportion of participants receiving penicillin with no adverse effects.

RESULTS

Initial literature search yielded 2945 studies, of which 23 studies were ultimately included in our review; 5056 study participants with reported history of penicillin allergy were challenged with a penicillin. After weighting for study sample size, a pooled average of 94.4% (95% confidence interval, 93.7%-95%) of participants tolerated the dose challenge without any adverse reaction.

CONCLUSION

Misrepresented penicillin allergy drives unnecessary use of alternative antibiotics, which may be less effective, more toxic, and more expensive than using penicillin. In addressing the problem of penicillin allergy over-diagnosis, evaluation should go beyond risk for type 1 hypersensitivity. Our data suggest that 94.4% of 5056 participants with reported penicillin allergy determined to be clinically appropriate for allergy evaluation tolerated repeat administration of penicillin-based antibiotics without any adverse reactions. This review generates meaningful information useful to clinical predictive analytics, in evaluating and managing patients with a reported history of penicillin allergy.

Paper Millifluidics Lab: Using a Library of Color Tests to Find Adulterated Antibiotics

A two to three period analytical chemistry experiment has been developed which allows second year students to explore chemical color tests used to detect adulterated pharmaceuticals. Students prepare several paper analytical devices (PADs) to generate positive and negative controls antibiotics, along with cutting agents such as starch and chalk. These PADs are used to identify the active ingredients and excipients in mystery tablets prepared by their classmates. In the second part of the lab, the students select an individual color test and design an experiment to quantify their mystery pill's active pharmaceutical ingredient (API). Nearly all of the student groups were able to successfully identify adulterants present in their mystery tablets. The quantification of the mystery tablets was also successful with all but one group calculating the correct concentration within 6%. In a postlab assessment, the students identified their largest gains in their ability to analyze data and other information, skill in science writing, and learning of laboratory techniques.

Selected Fungal Natural Products with Antimicrobial Properties

Fungal natural products and their effects have been known to humankind for hundreds of years. For example, toxic ergot alkaloids produced by filamentous fungi growing on rye poisoned thousands of people and livestock throughout the Middle Ages. However, their later medicinal applications, followed by the discovery of the first class of antibiotics, penicillins and other drugs of fungal origin, such as peptidic natural products, terpenoids or polyketides, have altered the historically negative reputation of fungal "toxins". The development of new antimicrobial drugs is currently a major global challenge, mainly due to antimicrobial resistance phenomena. Therefore, the structures, biosynthesis and antimicrobial activity of selected fungal natural products are described here.

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.

Novel methodology to measure pre-procedure antimicrobial prophylaxis: integrating text searches with structured data from the Veterans Health Administration's electronic medical record

Background

Antimicrobial prophylaxis is an evidence-proven strategy for reducing procedure-related infections; however, measuring this key quality metric typically requires manual review, due to the way antimicrobial prophylaxis is documented in the electronic medical record (EMR). Our objective was to electronically measure compliance with antimicrobial prophylaxis using both structured and unstructured data from the Veterans Health Administration (VA) EMR. We developed this methodology for cardiac device implantation procedures.

Methods

With clinician input and review of clinical guidelines, we developed a list of antimicrobial names recommended for the prevention of cardiac device infection. We trained the algorithm using existing fiscal year (FY) 2008–15 data from the VA Clinical Assessment Reporting and Tracking-Electrophysiology (CART-EP), which contains manually determined information about antimicrobial prophylaxis. We merged CART-EP data with EMR data and programmed statistical software to flag an antimicrobial orders or drug fills from structured data fields in the EMR and hits on text string searches of antimicrobial names documented in clinician’s notes. We iteratively tested combinations of these data elements to optimize an algorithm to accurately classify antimicrobial use. The final algorithm was validated in a national cohort of VA cardiac device procedures from FY2016–2017. Discordant cases underwent expert manual review to identify reasons for algorithm misclassification.

Results

The CART-EP dataset included 2102 procedures at 38 VA facilities with manually identified antimicrobial prophylaxis in 2056 cases (97.8%). The final algorithm combining structured EMR fields and text note search results correctly classified 2048 of the CART-EP cases (97.4%). In the validation sample, the algorithm measured compliance with antimicrobial prophylaxis in 16,606 of 18,903 cardiac device procedures (87.8%). Misclassification was due to EMR documentation issues, such as antimicrobial prophylaxis documented only in hand-written clinician notes in a format that cannot be electronically searched.

Conclusions

We developed a methodology with high accuracy to measure guideline concordant use of antimicrobial prophylaxis before cardiac device procedures using data fields present in modern EMRs. This method can replace manual review in quality measurement in the VA and other healthcare systems with EMRs; further, this method could be adapted to measure compliance in other procedural areas where antimicrobial prophylaxis is recommended.

The use and misuse of antibiotics in dentistry: A scoping review

BACKGROUND

To describe antibiotic prescribing behaviors in dentistry, including clinical and nonclinical indications for their use, the type and regimen of antibiotics prescribed, and factors influencing their prescription, the authors conducted a scoping review.

TYPES OF STUDIES REVIEWED

The authors conducted a scoping review of published literature by searching multiple databases. Key search terms included dentist, antibiotic, antimicrobial, antibacterial, prophylaxis, prescription, pattern, habit, knowledge, and practice. Two authors independently reviewed titles and abstracts by using detailed eligibility criteria. The authors placed no restrictions on study design or publication year. The authors qualitatively assessed studies by using a modified version of the Center for Evidence-Based Management's critical appraisal of a survey checklist.

RESULTS

The authors identified 1,912 studies but considered only 118 studies eligible for review. Most included studies were either cross-sectional surveys (81 studies) or prescription audits (25 studies) from various geographic locations. Publication dates ranged from 1982 through 2017. The authors examined prophylactic and therapeutic antibiotic use in 48 and 29 studies, respectively. Another 29 studies examined the use of both prophylactic and therapeutic antibiotics in dentistry. Overall, dentists prescribed a wide variety of antibiotic regimens for various clinical and nonclinical indications. Dentists have acquired their prescribing knowledge from a variety of sources and have changed their antibiotic prescribing practices throughout their careers for various reasons.

CONCLUSIONS AND PRACTICAL IMPLICATIONS

Considering the seriousness of antibiotic resistance, the authors highlight trends in antibiotic prescribing practices, characterize factors contributing to the use and misuse of antibiotics in dentistry, provide insight into the importance of antibiotic stewardship in the oral health setting, and encourage dentists to reflect on their antibiotic prescription practices.

Penicillin Allergy Assessment and Skin Testing in the Outpatient Setting

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

Risk of Adverse Reactions to Oral Antibiotics Prescribed by Dentists

Dentists prescribe a large portion of all oral antibiotics, and these are associated with a risk of adverse drug reactions (ADRs). The aim of this study was to quantify the risk of ADRs associated with oral antibiotics commonly prescribed by dentists. NHS Digital Prescribing data and Yellow Card Drug Analysis data for 2010 to 2017 were abstracted to quantify dental antibiotic prescribing in England, and the rate and types of ADRs associated with them. During the period of study, the mean number of actively practicing dentists in England was 23,624. Amoxicillin accounted for 64.8% of dental antibiotic prescribing and had the lowest reported rate of fatal ADRs (0.1/million prescriptions) and overall ADRs (21.5/million prescriptions). Indeed, amoxicillin was respectively 6 and 3 times less likely to cause an ADR than the other penicillins, penicillin V and amoxicillin + clavulanic acid, and appears to be very safe in patients with no history of penicillin allergy. In contrast, clindamycin, which is often used in patients with penicillin allergy, had the highest rate of fatal (2.9/million prescriptions) and overall (337.3/million prescriptions) ADRs, with Clostridiodes (formerly Clostridium) difficile infections pivotal to its ADR profile. Other amoxicillin alternatives, clarithromycin and metronidazole, while significantly worse than amoxicillin, were 3 and nearly 5 times less likely to cause an ADR than clindamycin. Ranked from least to most likely to cause an ADR, antibiotics most commonly prescribed were as follows: amoxicillin < cephalosporins < erythromycin < tetracyclines < azithromycin < metronidazole < amoxicillin + clavulanic acid < clarithromycin < penicillin V < clindamycin. This study confirmed the high level of safety associated with use of amoxicillin by dentists and the significantly worse rates of fatal and nonfatal ADRs associated with other penicillins and alternatives to amoxicillin for those who are penicillin allergic. In particular, clindamycin had the highest rate of fatal and nonfatal ADRs of any of the antibiotics commonly prescribed by dentists.

Cephalosporins: A Focus on Side Chains and β-Lactam Cross-Reactivity

Cephalosporins are among the most commonly prescribed antibiotic classes due to their wide clinical utility and general tolerability, with approximately 1-3% of the population reporting a cephalosporin allergy. However, clinicians may avoid the use of cephalosporins in patients with reported penicillin allergies despite the low potential for cross-reactivity. The misdiagnosis of β-lactam allergies and misunderstanding of cross-reactivity among β-lactams, including within the cephalosporin class, often leads to use of broader spectrum antibiotics with poor safety and efficacy profiles and represents a serious obstacle for antimicrobial stewardship. Risk factors for cephalosporin allergies are broad and include female sex, advanced age, and a history of another antibiotic or penicillin allergy; however, cephalosporins are readily tolerated even among individuals with true immediate-type allergies to penicillins. Cephalosporin cross-reactivity potential is related to the structural R1 side chain, and clinicians should be cognizant of R1 side chain similarities when prescribing alternate β-lactams in allergic individuals or when new cephalosporins are brought to market. Clinicians should consider the low likelihood of true cephalosporin allergy when clinically indicated. The purpose of this review is to provide an overview of the role of cephalosporins in clinical practice, and to highlight the incidence of, risk factors for, and cross-reactivity of cephalosporins with other antibiotics.

Cefuroxime, levofloxacin, esomeprazole, and bismuth as first-line therapy for eradicating Helicobacter pylori in patients allergic to penicillin

Background

Eradicating Helicobacter pylori infection is clinically challenging, notably in cases with penicillin allergy. Cephalosporin could be used in lieu of amoxicillin to eradicate Helicobacter pylori. The current work aimed to assess therapeutic efficacy and safety of a cefuroxime-based quadruple regimen in treatment-naïve individuals with penicillin allergy, as well as patient compliance.

Methods

In the present prospective single-center cohort study, 152 Helicobacter pylori infected individuals with penicillin allergy received eradication therapy with cefuroxime (500 mg twice/day), levofloxacin (500 mg once/day), esomeprazole (20 mg twice/day) and bismuth potassium citrate (220 mg twice/day; 14 days). Safety and compliance were evaluated 1 to 3 days upon eradication. The urea breath test was carried out 8 to 12 weeks upon eradication for efficacy assessment.

Results

This quadruple antimicrobial regimen eradicated the pathogen at 85.5% (95% confidence interval (CI) 79.6–90.8%), 88.4% (95% CI 83.0–93.2%) and 90.1% (95% CI 85.2–94.4%) in intention-to-treat, modified intention-to-treat and per-protocol analyses, respectively, with resistance rates of 4.6 and 40.0% in the background of cefuroxime and levofloxacin, respectively. Meanwhile, 21.3% of patients had adverse reactions, but none was serious. A total of 95.3% of patients showed good compliance. Poor compliance and cefuroxime resistance were detected by uni- or multivariate analyses as independent factors predicting therapeutic failure. Eradication rates in patients with dual levofloxacin and cefuroxime susceptibility, isolated levofloxacin resistance, isolated cefuroxime resistance and dual resistance were 97.2, 84.0, 50.0, and 0%, respectively (P = 0.002).

Conclusions

Cefuroxime, levofloxacin, esomeprazole, and bismuth achieved decent efficacy, safety and compliance as first-line antimicrobial regimen in patients with Helicobacter pylori and penicillin allergy.

The Basics of Penicillin Allergy: What A Clinician Should Know

Antimicrobials in the penicillin class are first line treatments for several infectious diseases in the pediatric and adult population today. In the United States, patients commonly report having a penicillin allergy, with penicillin being the most frequent beta-lactam allergy. However, very few patients experience a clinically significant immune-mediated allergic reaction to penicillin. If a true penicillin allergy exists, cross-reactivity to other beta-lactam antimicrobials may occur. Mislabeling patients with penicillin allergy can lead to a higher utilization of second line antimicrobial agents, potentially increasing costs and resistance due to a larger spectrum of activity. Pharmacists play an essential role in inquiring about patient specific reactions to presumed medication allergies and developing a further assessment plan, if needed, to determine if the medication allergy is real.

Beta-Lactam and Sulfonamide Allergy Testing Should Be a Standard of Care in Immunocompromised Hosts

Antibiotic allergies are reported in up to 1 in 4 immunocompromised hosts with significant impacts on antibiotic utilization and patient outcomes. Health services programs focused on de-labeling beta-lactam and sulfonamide allergy labels should be a standard of care in immunocompromised hosts.

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.

Necessity of Antibiotics to Reduce Inflammatory Complications after Third Molar Extractions: A Prospective Study

Aims and Objectives:

To determine the relationship between the usage of antibiotics postoperatively and inflammatory complications following third molar extractions.

Materials and Methods:

The sample was derived from Saudi Arabia private practitioners who were oral surgeons and was randomly categorized into two groups: group A, who took postoperative antibiotics, and group B, who have not taken antibiotics. The observed primary variable was the occurrence of inflammatory complications subsequent to removal of third molar.

Results:

The data were obtained from 35 oral surgeons, who gave details about 725 patients in whom 965 third molars were removed. A total of 455 (62.75%) patients have taken antibiotics postoperatively. The mean age was 28 ± 14.8 years. We noticed a very high male preponderance of 543 (74.89%). Mean body mass index was 26.7 ± 6.3 kg/m². The mean Preoperative Disease Severity Score and Operative Difficulty Score was 2.13 ± 2.1 and 12.1 ± 6.3, respectively.

Conclusion:

Fewer postoperative inflammatory complications were observed in subjects who have taken antibiotics after third molar removal.

Flucloxacillin Hypersensitivity: Patient Outcomes in a Multicenter Retrospective Study

BACKGROUND

Flucloxacillin is a narrow-spectrum, beta-lactamase-resistant penicillin. Type I (IgE-mediated) and type IV (T-cell-mediated) reactions are less frequently reported than with other penicillins.

OBJECTIVE

To undertake a detailed clinical characterization of a cohort of patients referred with suspected flucloxacillin hypersensitivity.

METHODS

We retrospectively analyzed demographic characteristics, presentation, investigation, and management of 108 patients presenting to 4 UK centers. Patients underwent skin prick and intradermal testing with flucloxacillin, major (benzylpenicilloyl poly-l-lysine) and minor determinants, amoxicillin, and benzylpenicillin with immediate and, where appropriate, delayed reading of the test. In the immediate group, a further 14 patients were tested to ampicillin and 16 to Augmentin (co-amoxiclav-combination of clavulanic acid and amoxicillin). Skin test-negative patients underwent oral drug provocation. A multistep protocol was used, depending on risk assessment.

RESULTS

Forty of 108 (37%) patients were diagnosed with hypersensitivity to flucloxacillin, of whom 33 (82.5%) showed immediate and 7 (17.5%) nonimmediate hypersensitivity, respectively. In the immediate group, most reactions were severe: 19 of 33 (58%). Intradermal testing had a higher negative predictive value (86%) in the immediate group than in the nonimmediate group (67%). Only a minority of patients (6 of 17 [35%]) with IgE-mediated allergy were cross-sensitized on intradermal testing with other penicillins, compared with 3 of 4 (75%) in the delayed group.

CONCLUSIONS

Immediate hypersensitivity reactions to flucloxacillin are more common than delayed. Cross-sensitization to other penicillins appears higher in delayed reactions than in immediate. The negative predictive value of intradermal testing is higher in the immediate group than in the nonimmediate group. Drug provocation testing remains the diagnostic criterion standard.

Clinical and economic burden of hospitalizations with registration of penicillin allergy

BACKGROUND

Penicillin allergy is commonly reported, but only a minority of claimants has a confirmed diagnosis. Nevertheless, patients labeled as having penicillin allergy are treated with second-line antibiotics, which are more expensive and less effective, possibly increasing the risk of drug-resistant infections.

OBJECTIVE

To compare hospitalizations with and without registration of penicillin allergy concerning their morbidity and hospital resource use.

METHODS

We analyzed a national administrative database containing a registration of all Portuguese hospitalizations from 2000 to 2014. All episodes occurring in adults with a penicillin allergy registration were compared with an equal number of hospitalizations without such registration and matched for inpatients' age, sex, and main diagnosis. We compared those episodes concerning their length of stay, hospital price charges, comorbidities, and frequency of drug-resistant infections. Differences between medical and surgical hospitalizations were explored.

RESULTS

Hospitalizations with registration of penicillin allergy (n = 102,872) had a longer average length of stay than the remainder episodes (8 vs 7 days; P < .001) and higher hospital charges (3,809.0 vs 3,490.0 USD; P < .001). Inpatients with penicillin allergy registration also had a higher mean Charlson Comorbidity Index (0.91 vs 0.76; P < .001) and a significantly higher frequency of infections by several agents, including methicillin-resistant Staphylococcus aureus, Enterococcus species, and Escherichia coli. Among surgical episodes, septicemia was 1.2-fold more frequent among penicillin allergy cases.

CONCLUSION

Hospitalizations with registration of penicillin allergy are associated with increased economic costs and frequency of infections by drug-resistant agents, reinforcing the need to establish a correct diagnosis of penicillin allergy.

Presumed β-Lactam Allergy and Cross-reactivity in the Operating Theater: A Practical Approach

A β-lactam allergy is the most common suspected in-hospital drug allergy. This article aims to provide a practical approach to a patient with presumed β-lactam allergy in the perioperative setting.

Supplemental Digital Content is available in the text.

The Effect of Non-penicillin Antibiotic Regimens on Neonatal Outcomes in Preterm Premature Rupture of Membranes

Objective  A 7-day course of a penicillin (PCN) and macrolide is standard of care (SAR) in preterm premature rupture of membranes (PPROM). Data regarding alternative antibiotic regimens are limited. We sought to assess the impact of non-PCN regimens on neonatal outcomes. Study Design  Secondary analysis of randomized controlled trial of antenatal magnesium sulfate. Singleton, nonanomalous pregnancies complicated by PPROM at > 24 weeks of gestation receiving the SAR were compared with women receiving a non- β -lactam regimen and a macrolide (NPCR). Primary outcome was a neonatal composite. Secondary outcomes included pregnancy latency, endometritis, and chorioamnionitis. Results  A total of 949 women met inclusion criteria; 821(56%) received the SAR and 128(8.8%) received NPCR. Adjusted models did not demonstrate worse outcomes (AOR [adjusted odds ratio] = 0.50; 95% CI [confidence interval]: 0.22-1.11). Neonates receiving SAR were less likely to have bronchopulmonary dysplasia (BPD; p  = 0.03) but more likely to have severe necrotizing enterocolitis (sNEC; p  = 0.04). Risk for chorioamnionitis and median latency did not differ between groups but women receiving the SAR were less likely to get endometritis (AOR = 0.35; 95% CI: 0.14-0.91). Conclusions  In this cohort, receiving NPCR in the setting of PPROM did not impact the overall risk of adverse neonatal outcomes or latency, but did increase the risk of endometritis. Alterations in individual neonatal morbidities suggest follow-up studies are needed.

Controversies in Drug Allergy: Beta-Lactam Hypersensitivity Testing

All beta-lactam use is associated with a certain rate of adverse reactions. Many of these adverse reactions result in an allergy to the beta-lactam being entered into the patient's medical record. Unfortunately, only a small minority of these recorded allergies are clinically significant immunologically mediated drug hypersensitivity. An unconfirmed allergy to beta-lactams is a significant public health risk, because patients so labeled typically do not receive narrow-spectrum penicillins and cephalosporins when clinically indicated. The alternative antibiotics they receive result in poorer clinical outcomes, increased incidence of serious antibiotic-resistant infections, prolonged hospitalizations, and greater health care utilization. There is a wide variation in beta-lactam allergy incidence and prevalence around the world, based in part on the specific beta-lactams used and overused. There is a wide variation in specific protocols used to confirm current tolerance of beta-lactams and remove these inaccurate allergy reports. Harmonizing testing protocols, when possible, may lead to more widespread use of narrow-spectrum beta-lactams, when clinically indicated, and improve patient safety worldwide. Further research is needed to better understand the regional differences in reporting beta-lactam allergy as this relates to regional differences in beta-lactam use and overuse, the frequency of clinically significant immunologically mediated beta-lactam hypersensitivity, and the optimal testing strategies to confirm current tolerance, based on presenting clinical symptoms.

Evaluation of Pharmacy-Developed Antibiotic Desensitization Protocols

BACKGROUND

Parameters within reconstitution, storage, stability, and administration may be optimized according to the unique pharmacokinetics of each antibiotic to ensure a successful desensitization.

OBJECTIVE

The study aims to evaluate the successfulness and safety of antibiotic desensitization protocols developed by the pharmacy department at our institution.

METHODS

A retrospective study was conducted at an 800-bed, urban, tertiary care, academic medical center. A total of 36 patients 18 years of age or older, admitted to our intensive care units between March 2013 and July 2017, who underwent antibiotic desensitization utilizing our pharmacy developed protocols were included.

RESULTS

In 36 patients, 61 desensitization cases were identified and included; 17 (47%) were male, 27 (75%) were Caucasian, and the median age was 55 years (range 19-94). In all, 15 different antibiotics were administered for desensitization, with meropenem (n = 12, 20%), ampicillin (n = 7, 11%), piperacillin/tazobactam (n = 7, 11%), and penicillin (n = 7, 11%) being the most common; 59 (97%) of 61 desensitizations were completed successfully with or without experiencing reactions, and 53 (89%) of the successful desensitization cases were completed without reactions. Two cases were categorized as anaphylaxis, which was severe enough to terminate the desensitization process. Of the 59 cases successfully completed, the 6 (10%) cases that experienced reactions were managed successfully during desensitization with completion of the process. Conclusion and Relevance: The findings suggest that our pharmacy-developed antibiotic desensitization protocols are successful and safe and may be adapted by other institutions.

The anti-penicillin antibodies levels in sensitive and insensitive people to intradermal skin test

BACKGROUND

The hypersensitivity reaction to penicillin is a public health problem. Immunological responses to penicillin and other beta-lactam antibiotics can be classified into immediate and non-immediate responses. The immediate hypersensitivity is mediated by IgE; however, the non-immediate sensitivity is facilitated by other isotypes of antibody or T lymphocytes.

OBJECTIVE

This research detected the non-IgE antibody value against penicillin in allergic and normal people.

METHODS

Thirty-eight samples from patients with positive or negative intradermal skin testing results of penicillin allergy were included in this study. The total antibody and IgM levels against penicillin G were defined by in-house ELISA test.

RESULTS

The results showed a significant (P< 0.05) elevation in total immunoglobulin and non-IgM anti-penicillin antibody of sensitive groups; however, the anti-penicillin IgM was significantly greater in non-sensitive peoples.

CONCLUSIONS

Although the sensitized people to penicillin cannot be certainly detected with the total antibody, specific IgG and IgM value against penicillin, these values are good indicators for prediction of immediate and late response of the immune system to penicillin.

Bismuth improves efficacy of proton-pump inhibitor clarithromycin, metronidazole triple Helicobacter pylori therapy despite a high prevalence of antimicrobial resistance

BACKGROUND

Helicobacter pylori (H. pylori) eradication has become increasingly difficult especially for penicillin allergy patients.

AIMS

To evaluate the efficacy of adding bismuth or high-dose metronidazole to an H. pylori eradication regimen containing a proton-pump inhibitor, clarithromycin, and metronidazole in patients allergic to penicillin.

METHODS

Pilot study in which penicillin-allergic, treatment-naive subjects were randomized (1:1) to 14-day esomeprazole (20 mg q12h), clarithromycin (500 mg q12h), and high dose of metronidazole (400 mg q6h) with (BECM group) or without (ECM group) bismuth (600 mg q12h). Eradication was confirmed by ¹³ C-urea breath test 6 weeks after therapy. Antimicrobial susceptibility was assessed by the agar dilution method. Adverse events were recorded.

RESULTS

Sixty-six subjects were randomized, four were lost to follow-up and eight violated the protocol. The eradication rates were 63.6% (95% CI: 47.2%-80.0%) for ECM vs 84.8% (95% CI 72.6%-97.1%) (p = .049) for BECM by intention-to-treat, 67.7% (95% CI 51.3%-84.2%) vs 90.3% (95% CI 79.9%-100%) (p = .029) by modified ITT, and 70% (95% CI 53.6%-86.4%) vs 96% (95% CI 88.3%-100%) (P = .033) by per-protocol. Metronidazole, clarithromycin, and dual-resistant rates were 74.2%, 24.2%, and 18.2%, respectively. The cure rates were significantly improved by the addition of bismuth for both clarithromycin-resistant isolates (100% vs 25%, P = .024) and metronidazole-resistant isolates (94.7% vs 63.6%, P = .043). Adverse events were reported by 45.5% of subjects in ECM group and 48.5% in the BECM group (P = .805).

CONCLUSIONS

This prospective trial demonstrated that while high-dose metronidazole could not completely overcome metronidazole resistance, bismuth was additive and improved the overall cure rates by 21%-26%.