Penicillin allergy: consider trying penicillin again

Penicillin minor determinants: History and relevance for current diagnosis

OBJECTIVE

To review the history of the penicillin minor determinants and evaluate their relevance for current diagnosis.

DATA SOURCES

Skin testing to detect immunoglobulin E (IgE) sensitivity to penicillins in patients with a history of penicillin allergy has been the subject of more than 55 years of published research involving tens of thousands of patients.

STUDY SELECTIONS

Selection of data was based on its relevance to the objective of this article.

RESULTS

It was established early on that testing with the major penicilloyl determinant using the polyvalent penicilloyl-polylysine (PPL) is negative in a substantial portion (10% to 64%, including recent increases) of those at risk for immediate hypersensitivity reactions. A variety of minor penicillin determinants are clinically significant in that their use in skin testing is essential to detect all those at risk. In particular, a minor determinant mixture of benzylpenicillin, benzylpenicilloate, and benzylpenilloate, used in conjunction with PPL, has been shown in numerous studies to achieve an average negative predictive value (NPV) of 97.9% in history-positive patients. Benzylpenicillin alone, as the sole minor determinant, leaves many skin test-positive patients undiscovered. Use of amoxicillin as an additional minor determinant reagent appears to identify another 2% to 8% of skin test-positive patients in some populations.

CONCLUSION

IgE skin testing, using both the major and appropriate minor determinants of penicillin, can identify, with a high degree of reliability (NPV ∼97%), penicillin allergy history-positive patients who can receive beta-lactam antibiotics without concern for serious acute allergy, including anaphylaxis. The few false-negative skin tests reported globally are largely confined to minor, self-limited cutaneous reactions.

UHPLC-MS/MS method for the quantitation of penicillin G and metabolites in citrus fruit using internal standards

Penicillin G has been applied to citrus trees as a potential treatment in the fight against Huanglongbing (HLB). Here, we have developed and validated a method to identify and quantitate penicillin G and two of its metabolites, penillic acid and penilloic acid, in citrus fruit using ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). This method improves upon a previous method by incorporating isotopically labeled internal standards, namely, penillic acid-D₅, and penilloic acid-D₅. These standards greatly enhanced the accuracy and precision of our measurements by compensating for recovery losses, degradation, and matrix effects. When 2g of citrus fruit sample is extracted, the limits of detection (LOD) were determined to be 0.1ng/g for penicillin G and penilloic acid, and 0.25ng/g for penillic acid. At fortification levels of 0.1, 0.25, 1, and 10ng/g, absolute recoveries for penillic and penilloic acids were generally between 50-70%. Recoveries corrected with the isotopically labeled standards were approximately 90-110%. This method will be useful for the identification and quantitation of drug residues and their degradation products using isotopically labeled standards and UHPLC-MS/MS.

Identification of Penicillin G Metabolites under Various Environmental Conditions Using UHPLC-MS/MS

In this work, we investigate the stability of penicillin G in various conditions including acidic, alkaline, natural acidic matrices and after treatment of citrus trees that are infected with citrus greening disease. The identification, confirmation, and quantitation of penicillin G and its various metabolites were evaluated using two UHPLC-MS/MS systems with variable capabilities (i.e., Thermo Q Exactive Orbitrap and Sciex 6500 QTrap). Our data show that under acidic and alkaline conditions, penicillin G at 100 ng/mL degrades quickly, with a determined half-life time of approximately 2 h. Penillic acid, penicilloic acid, and penilloic acid are found to be the most abundant metabolites of penicillin G. These major metabolites, along with isopenillic acid, are found when penicillin G is used for treatment of citrus greening infected trees. The findings of this study will provide insight regarding penicillin G residues in agricultural and biological applications.

Management of allergy to penicillins and other beta-lactams

The Standards of Care Committee of the British Society for Allergy and Clinical Immunology (BSACI) and an expert panel have prepared this guidance for the management of immediate and non-immediate allergic reactions to penicillins and other beta-lactams. The guideline is intended for UK specialists in both adult and paediatric allergy and for other clinicians practising allergy in secondary and tertiary care. The recommendations are evidence based, but where evidence is lacking, the panel reached consensus. During the development of the guideline, all BSACI members were consulted using a Web-based process and all comments carefully considered. Included in the guideline are epidemiology of allergic reactions to beta-lactams, molecular structure, formulations available in the UK and a description of known beta-lactam antigenic determinants. Sections on the value and limitations of clinical history, skin testing and laboratory investigations for both penicillins and cephalosporins are included. Cross-reactivity between penicillins and cephalosporins is discussed in detail. Recommendations on oral provocation and desensitization procedures have been made. Guidance for beta-lactam allergy in children is given in a separate section. An algorithm to help the clinician in the diagnosis of patients with a history of penicillin allergy has also been included.

Antibiotic hypersensitivity reactions and approaches to desensitization

Before initiating antibiotic therapy, drug hypersensitivity is an important consideration, and a common strategy is to avoid giving patients medications when a high likelihood of severe reactions exists. With an increase in antibiotic resistance and a decrease in novel antibiotics, there is greater pressure to consider antibiotics in patients with a history of adverse reactions. The major concerns include IgE-mediated, or type I, reactions, anaphylaxis, Stevens-Johnson syndrome, and toxic epidermal necrolysis. Some antibiotics with similar characteristics, such as cephalosporins and penicillins, may be given safely to patients with a certain allergy profile. There is still greater concern when considering antibiotics for patients with reported allergy. Desensitization is a strategy to safely induce drug tolerance to a specific drug to limit the possibility of a type I reaction.

The prevalence and reliability of self-reported penicillin allergy in a community hospital

Background

Penicillin (PCN) accounts for most cases of antibiotic allergies. Reported PCN allergy deprives the patient from this class of antibiotics and creates hesitancy in using other beta-lactam antibiotics. The aim of this study is to report the prevalence of self-reported PCN allergy among adult patients admitted to the hospital and to examine the probable validity of these reports.

Methods

A questionnaire was conducted among 192 patients with self-reported PCN allergy who were admitted to a community hospital between July 25, 2011 and January 25, 2012. Patients admitted with an infection and treated with a beta-lactam were also followed until hospital discharge.

Results

The mean age of patients at the time of their self-reported allergic reaction was 20.3 years. The most common allergic symptoms reported in decreasing order of frequency were itchy rash, angioedema, and urticaria. Based on analysis of the questionnaires, 121 patients (63.0%) had probable PCN allergy, 54 (28.1%) had possible PCN allergy, and 17 (8.9%) were unlikely to have a PCN allergy. Fifty-one participants (26.6%) had self-reported subsequent exposure to PCN in their life. This subsequent exposure was well tolerated in 86.3% of the participants. Fifty participants (25.9%) had self-reported subsequent exposure to a first generation cephalosporin and it was well tolerated in 78.4% of them.

Conclusion

Taking a detailed history from patients with self-reported PCN allergy can help to distinguish a true PCN allergy from a false positive report of allergy and hence allow clinicians to use this important class of antibiotics when truly indicated.

Evaluation of Treatment with Oseltamivir during the 2009 H1N1 (Swine Flu) Pandemic: The Problem of Incomplete Clinical Information

During the H1N1 (swine flu) pandemic of 2009, the World Health Organization (WHO) confirmed more than 14,000 deaths globally; this included a death toll of 147 in Iran. In order to evaluate (a) the appropriateness of the Oseltamivir dose through calculation of a patient's creatinine clearance (CrCl) and (b) the quality of data in the medical charts, we conducted a retrospective study at the Shariati Hospital in Tehran. All admissions to the hospital between the dates i October 2009 and 31 January 2010 were evaluated, amounting to a total of 51 patients' charts, including 8 outpatient charts. Of these 51 charts, 26 (51%) contained all the information necessary to evaluate the CrCl. However, there was at least one piece of information missing (e.g. the patient's weight; serum creatinine) from each of the remaining 25 charts (49% of the sample), which made it impossible for us to evaluate the dose. These results demonstrate how crucially important it is to ensure that all the necessary patient information is correctly registered at the time of admission in order to minimise medication errors.

Diagnosis of drug hypersensitivity in children and adolescents: discrepancy between physician-based assessment and results of testing

BACKGROUND

Diagnosis of drug hypersensitivity is often based on history alone. But such a vague diagnosis may cause limitations of therapeutic options in the future. To confirm or rule out drug hypersensitivity, skin testing, in vitro studies, and challenge tests are necessary. However, the diagnostic value of this complex and time-consuming allergologic work-up, especially in children, remains controversial.

OBJECTIVE

Aim of this retrospective analysis was to compare the results of diagnostic testing in children and adolescents with drug hypersensitivity diagnosed on clinical grounds, i.e., temporal relationship and observation of symptoms alone.

METHODS

We studied 43 children and adolescents (23 females, 20 males, mean age 13) with a history of immediate or delayed hypersensitivity symptoms in temporal relation to drug treatment using standardized skin testing followed by oral challenges. Patients with suspected penicillin hypersensitivity were further evaluated with in vitro tests.

RESULTS

Drug hypersensitivity was excluded in 40 patients by tolerated oral challenge tests with the incriminated drug. In two patients, positive challenge tests confirmed non-steroidal anti-inflammatory drug hypersensitivity. One patient with amoxicillin-associated exanthema developed positive late skin test reactions to aminopenicillins.

CONCLUSION

In childhood and adolescence, allergologic testing in cases of suspected drug hypersensitivity is of importance both to establish a correct diagnosis and to prevent unjustified withholding of a drug or class of drugs.

Identification of new minor metabolites of penicillin G in human serum by multiple-stage tandem mass spectrometry

Liquid chromatography/mass spectrometry (LC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) were applied to characterize drug metabolites. Although these two methods have overcome the identification and structural characterization of metabolites analysis, they remain time-consuming processes. In this study, a novel multiple-stage tandem mass spectrometric method (MS(n) ) was evaluated for identification and characterization of new minor metabolism profiling of penicillin G, one of the β-lactam antibiotics, in human serum. Seven minor metabolites including five phase I metabolites and two phase II metabolites of penicillin G were identified by using data-dependent LC/MS(n) screening in one chromatographic run. The accuracy masses of seven identified metabolites of penicillin G were also confirmed by mass spectral calibration software (MassWorks™). The proposed data-dependent LC/MS(n) method is a powerful tool to provide large amounts of the necessary structural information to characterize minor metabolite in metabolism profiling.

Reexamining syphilis: an update on epidemiology, clinical manifestations, and management

OBJECTIVE

To review the epidemiology, clinical features, diagnosis, and treatment of syphilis.

DATA SOURCES

Studies and reviews were abstracted from MEDLINE (1950-April 2007) using the search term syphilis. All papers were cross-referenced to identify additional studies and reviews for inclusion.

STUDY SELECTION AND DATA EXTRACTION

Pertinent original research articles, review articles, and book chapters were evaluated.

DATA SYNTHESIS

Syphilis is a spirochetal disease that has plagued mankind for centuries. Following a low incidence of syphilis in the US for the last 2 decades, rates are now increasing both in the US and other parts of the world. Once acquired, syphilis can pass through 4 distinct stages of disease: primary syphilis, secondary syphilis, latent syphilis, and tertiary syphilis, with each stage being characterized by different symptoms and levels of infectivity. Diagnosis is made primarily by serologic assays with nontreponemal tests such as the Venereal Disease Research Laboratory and the Rapid Plasma Reagin assay used for screening. Treponemal tests including the Treponema pallidum particle agglutination and the fluorescent treponemal antibody absorption test are then used for confirmation. Recommended treatment regimens are based largely on uncontrolled trials and clinical experience. Penicillin is the treatment of choice, with the preparation and treatment duration varying for different stages. Benzathine penicillin is the treatment of choice for all stages of syphilis except neurosyphilis, for which aqueous crystalline penicillin or procaine penicillin is used due to the central nervous system penetration of these formulations. Coinfection with both syphilis and HIV occurs frequently due to common risk factors. These 2 diseases interact with each other, making both diagnosis and treatment more complicated.

CONCLUSIONS

Clinicians should be aware of the signs and symptoms of syphilis as well as current guidelines for the management and treatment of this disease.

Penicillin allergy skin testing: what do we do now?

Drug-induced anaphylaxis remains a relatively infrequent event. However, penicillin and associated beta-lactam antibiotics remain a primary cause of anaphylaxis. Penicillin allergies are undoubtedly overreported, and patients with suspected penicillin allergy can be treated with antibiotic alternatives. Penicillin allergy skin testing is a simple and effective way to identify true penicillin allergy. Skin testing involves testing for both major and minor determinants and should be conducted in a facility with available life-support equipment. The commercial major determinant product, benzylpenicilloyl-polylysine, was removed from the market in 2004; this action compromised the ability of clinicians to evaluate a patient's likely response to penicillin therapy. Alternatives to skin testing include laboratory synthesis of major determinants, use of the radioallergosorbent test (RAST), or a combination of RAST and minor determinant skin testing. Patients with suspected penicillin allergy can undergo desensitization if they require penicillin therapy. The planned return of a commercial major determinant will hopefully resolve this issue.

Aminopenicillin-induced exanthema allows treatment with certain cephalosporins or phenoxymethyl penicillin

OBJECTIVES

Aminopenicillin-induced exanthema poses a problem in the management of infectious diseases. Due to theoretically possible immunological cross-reactivity, all beta-lactam drugs, i.e. penicillins, penicillin derivatives and cephalosporins, are usually avoided. The available alternative antibiotics (macrolides, quinolones and glycopeptides) may be less effective, have more side effects, and their use increases medical costs. Moreover, their use contributes to the increasing bacterial resistance to antibiotics. The aim of the study is to demonstrate that patients with aminopenicillin-induced exanthema may receive specific beta-lactams for future antibiotic therapy.

METHODS

Skin testing followed by oral challenges to identify beta-lactams that are tolerated by patients despite confirmed delayed-type non-immunoglobulin E (IgE)-mediated allergic hypersensitivity to aminopenicillins.

RESULTS

Sixty-nine out of 71 patients (97.2%) with non-IgE-mediated allergic hypersensitivity to aminopenicillins tolerate cephalosporins without an aminobenzyl side chain such as cefpodoxime or cefixime and 51 patients (71.8%) also tolerate phenoxymethyl penicillin.

CONCLUSIONS

The majority of patients with non-IgE-mediated allergic hypersensitivity to aminopenicillins do not cross-react to certain cephalosporins or phenoxymethyl penicillin. Skin and drug challenge tests can be helpful to determine individual cross-reactivity.

Penicillin skin testing in patients with a history of beta-lactam allergy

BACKGROUND

Vancomycin and fluoroquinolones are commonly used in patients with a history of penicillin allergy.

OBJECTIVE

To determine the safety and utility of penicillin skin testing (PST).

METHODS

Retrospective study of patients with a history of penicillin allergy between April 1, 1999, and September 30, 2004. Penicillin skin testing was performed by means of standard methods using benzylpenicilloyl-polysine, penicillin G, and histamine and saline controls.

RESULTS

Of 596 patients studied, 25.3% were outpatients, 50.3% were inpatients, and 24.3% were intensive care unit patients. The most common antibiotics used during the time of PST were vancomycin and fluoroquinolones. Results of PST were negative in 88.4% of patients, positive in 8.2%, and indeterminate in 3.4%. One patient (0.17%) developed urticaria immediately after PST. Fifty-five percent of patients with negative PST results were changed to a beta-lactam drug, more frequently in the intensive care unit vs the outpatient setting (70.3% vs 8.6%; P < .001) and in adults vs patients younger than 18 years (58.6% vs 8.1%; P < .001). A beta-lactam antibiotic was used in 290 patients with negative PST results. Of the patients given beta-lactam antibiotics, 5 (1.7%) had adverse reactions: 2 had hives after 16 and 20 days of therapy, 1 had a nonspecific rash after 17 days of therapy, 1 had flushing and urticaria 3 hours after a test dose of piperacillin-tazobactam, and 1 had a pruritic rash after 12 hours of therapy.

CONCLUSIONS

Patients with a history of penicillin allergy can safely use beta-lactam drugs if negative PST results.

Clinical outcomes of penicillin skin testing

BACKGROUND

Penicillin or cephalosporin allergy is a common problem with antibiotic drug prescribing in hospitalized patients.

OBJECTIVES

To study the various clinical outcomes of penicillin skin testing (PST) in a community teaching hospital and to determine the percentage of patients who have an antibiotic drug modification after PST.

METHODS

This study was a retrospective medical record review of all inpatients who underwent PST in 6.6 years. Information was collected on 101 patients using a detailed data collection form. Data were summarized using descriptive statistics, including frequencies and percentages.

RESULTS

Of the 101 patients who underwent PST, 92 had a negative result and 5 had a positive result; in 4 patients the test result was indeterminate. There was a 96% (67/70) reduction in the use of vancomycin and a 96% (23/24) reduction in the use of fluoroquinolones after PST in patients with negative results. Forty-nine percent of patients with negative PST results were administered a penicillin-based drug, and 48% were given a cephalosporin. Cultures were positive most commonly for Staphylococcus aureus and enterococcus. There were no serious adverse reactions to PST or to the use of penicillins or cephalosporins after a negative PST result.

CONCLUSIONS

Penicillin skin testing lowered the use of vancomycin and fluoroquinolones and increased the use of penicillin-based drugs and cephalosporins in patients with a history of beta-lactam drug allergies.