Penicillins and cephalosporins as allergens--structural aspects of recognition and cross-reactions

Penilloic acid is the chief culprit involved in non-IgE mediated, immediate penicillin-induced hypersensitivity reactions in mice

Metabolites/impurities (MIs) of penicillin are normally considered to be the main substances inducing immediate hypersensitivity reactions in penicillin treatment. Our previous research found that penicillin can cause non-allergic hypersensitivity reactions (NAHRs) by directly triggering vascular hyperpermeability and exudative inflammation. However, the chief culprits and underlying mechanisms involved in penicillin-induced NAHRs have not yet been fully elucidated. In this study, we used a combination of approaches including a mouse non-allergic hypersensitivity reaction model, UPLC-MS/MS analyses of arachidonic acid metabolites (AAMs), immunoblotting technique, and molecular docking, etc to investigate the culprits involved in penicillin-induced hypersensitivity reactions. We found penilloic acid, one of the main MIs of penicillin, could trigger NAHRs via inducing increased vascular permeability, while the other MIs did no exhibit similar effect. Penilloic acid-induced reactions were not IgE-dependent. Significantly increased arachidonic acids and cascade metabolites in lungs, and activation of RhoA/ROCK signaling pathway in the ears and lungs of mice were noticed after once administration of penilloic acid. This study revealed that penilloic acid was the chief culprit involved in penicillin-induced immediate NAHRs in mice, which mainly associated with direct stimulation of vascular hyperpermeability and exudative inflammation. The activations of AAMs and RhoA/ROCK signaling pathway played important roles in these reactions.

Classifying cephalosporins: from generation to cross-reactivity

PURPOSE OF REVIEW

To review the most recent literature studying the classifications, immunochemistry, and crossreactivity of allergy reactions to cephalosporins.

RECENT FINDINGS

Over the last five years, research interest has focused on three areas related to cephalosporin allergy: cross-reactivity among cephalosporins and with other beta-lactams; the incidence of adverse reactions in penicillin allergy patients or in reported penicillin allergy labels; and new cephalosporins structures involved in the immunological recognition.

SUMMARY

Meta-analysis of a substantial number of studies shows that cephalosporins are safer than previously thought. Evidence supports two main conclusions in that regard. First, there is a relatively low percentage of cross-reactivity between cephalosporins and other beta-lactams with penicillins in penicillin allergy patients. Second, there is a very low incidence of allergy reactions in nonselected as well as in selected penicillin allergy patients when cephalosporins are used prior to surgical intervention.On the other hand, few structures have been discovered related to the immune mechanism of cephalosporin allergy reactions, and these are far from being ready to use in clinical practice.

Piperacillin-Tazobactam Hypersensitivity: A Large, Multicenter Analysis

BACKGROUND

Piperacillin/tazobactam is a broad-spectrum penicillin. Hypersensitivity reactions are less commonly reported than with other penicillins except in patients with cystic fibrosis.

OBJECTIVE

Detailed clinical characterization of a patient cohort referred with suspected piperacillin-tazobactam hypersensitivity.

METHODS

Retrospective analysis of the demographic characteristics, clinical presentation, investigation, and management of 87 patients presenting to 5 European allergy centers. Patients underwent skin prick and intradermal testing with piperacillin/tazobactam, major (penicilloyl-polylysine) and minor (sodium penilloate) determinants, amoxicillin, benzylpenicillin, flucloxacillin, co-amoxiclav, clavulanic acid, and meropenem with immediate and, where appropriate, delayed reading of tests. Skin test-negative patients underwent drug provocation to piperacillin/tazobactam and/or other penicillins. A multistep protocol was used, depending on risk assessment.

RESULTS

Forty-eight of 87 (55%) patients were diagnosed with hypersensitivity to piperacillin/tazobactam with either positive skin or drug provocation test results, of whom 10 (21%) had a diagnosis of cystic fibrosis. Twenty-six (54%) patients presented with immediate and 22 (45%) with nonimmediate hypersensitivity. Patients with cystic fibrosis predominantly presented with nonimmediate hypersensitivity (70%). Reactions were severe in 52% of immediate reactors (Brown's anaphylaxis grade 3) and moderately severe (systemic involvement) in 75% of nonimmediate reactors. The number of patients with negative skin test results tolerating reintroduction was comparable in immediate (80%) and nonimmediate (88%) hypersensitivity. One-third of patients were cross-sensitized to other penicillins. The cross-sensitization pattern raised the possibility of tazobactam allergy in 3 patients. In 21 patients selectively sensitized to piperacillin/tazobactam (12 immediate, 9 nonimmediate), tolerance to other beta-lactams was demonstrated by drug provocation testing.

CONCLUSIONS

Piperacillin-tazobactam caused immediate and nonimmediate hypersensitivity with similar frequency. Most patients were selectively sensitized and tolerated other penicillins. Some patients may be allergic to the beta-lactamase inhibitor only.

Neo-antigens for the serological diagnosis of IgE-mediated drug allergic reactions to antibiotics cephalosporin, carbapenem and monobactam

New antigens deriving from -lloyl and -llanyl, major and minor determinants, respectively, were produced for β-lactam antibiotics cefuroxime, cefotaxime, ceftriaxone, meropenem and aztreonam. Twenty β-lactam antigens were produced using human serum albumin and histone H1 as carrier proteins. Antigens were tested by multiplex in vitro immunoassays and evaluated based on the detection of specific IgG and IgE in the serum samples. Both major and minor determinants were appropriate antigens for detecting specific anti-β-lactam IgG in immunised rabbit sera. In a cohort of 37 allergic patients, we observed that only the minor determinants (-llanyl antigens) were suitable for determining specific anti-β-lactam IgE antibodies with high sensitivity (< 0.01 IU/mL; 24 ng/L) and specificity (100%). These findings reveal that not only the haptenisation of β-lactam antibiotics renders improved molecular recognition events when the 4-member β-lactam ring remains unmodified, but also may contribute to develop promising minor antigens suitable for detecting specific IgE-mediated allergic reactions. This will facilitate the development of sensitive and selective multiplexed in vitro tests for drug-allergy diagnoses to antibiotics cephalosporin, carbapenem and monobactam.

Immediate cephalosporin allergy

BACKGROUND

Patients who suffer from acute IgE-mediated allergy to a cephalosporin antibiotic are frequently assumed to be at high risk of allergy to other cephalosporins and penicillins.

AIM

To define cross-reactivity patterns in patients with confirmed allergy to a cephalosporin.

METHODS

Subjects presenting with a history of immediate allergy to a cephalosporin-family antibiotic between March 2009 and July 2017 were investigated with specific IgE testing to penicillin, amoxycillin and cefaclor, followed by skin prick testing, intradermal testing and drug provocation testing with a panel of penicillins and cephalosporins.

RESULTS

Out of 564 subjects with a reported beta-lactam allergy, 90 identified a cephalosporin as their index drug. Fifty-five (61.1%) of the 90 subjects tested had a history consistent with an IgE-mediated reaction, of whom 24 (43.6%) were proven to be allergic to their index cephalosporin. Twenty (83.3%) of the 24 were allergic only to their index cephalosporin. Of the four remaining subjects, two were co-sensitised to another beta-lactam with a similar side chain, while the other two had no specific cross-reactivity pattern. Major and minor penicillin determinants were negative for all cephalosporin-allergic individuals.

CONCLUSION

In our cohort, cephalosporin allergy does not appear to be a class effect, with most cases found allergic only to their index cephalosporin. Co-sensitisation to other cephalosporins or penicillins was uncommon, and when it occurred, was usually consistent with side chain cross-reactivity.

Boosting the sensitivity of in vitro β-lactam allergy diagnostic tests

The synthesis of structurally new haptens and the development of suitable antigens are essential for boosting the sensitivity of drug allergy diagnostic testing.

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.

Proper Cut-off Levels of Serum Specific IgE to Cefaclor for Patients with Cefaclor Allergy

PURPOSE

Cefaclor, a second-generation oral cephalosporin, is known to cause IgE-mediated hypersensitivity. Assays of serum-specific IgE (sIgE) to cefaclor are commercially available via the ImmunoCAP system (Thermo Fisher Scientific). While serum levels of sIgE >0.35 kU/L are considered indicative of an allergy, some patients with cefaclor allergy show low serum IgE levels. This study aimed to evaluate the proper cut-off levels of sIgE in the diagnosis of immediate hypersensitivity to cefaclor.

MATERIALS AND METHODS

A total of 269 patients with drug allergy history, who underwent assays of sIgE to cefaclor at Ajou University hospital and Dong-A University Hospital, were reviewed retrospectively. Among them, 193 patients exhibited cefaclor-induced immediate hypersensitivity with certain or probable causality of an adverse drug reaction according to the WHO-UMC (the World Health Organization-the Uppsala Monitoring Centre) algorithm, and 76 controls showed delayed hypersensitivity reactions to non-antibiotics.

RESULTS

In total, 126 of the 193 patients (65.3%) experienced anaphylaxis; they had higher serum sIgE levels than patients with immediate hypersensitivity who did not experience anaphylaxis (6.36±12.39 kU/L vs. 4.28±13.61 kU/L, p<0.001). The best cut-off value for cefaclor-induced immediate hypersensitivity was 0.11 kU/L, with sensitivity of 80.2% and specificity of 81.6%. A cut-off value of 0.44 kU/L showed the best sensitivity (75.4%) and specificity (65.7%) for differentiating anaphylaxis from immediate hypersensitivity reactions.

CONCLUSION

Patients with cefaclor anaphylaxis exhibit high serum IgE levels. A cut-off value of 0.11 kU/L of sIgE to cefaclor is proper for identifying patients with cefaclor allergy, and 0.44 kU/L may be useful to detect anaphylaxis.

Cross-Reactivity and Tolerability of Cephalosporins in Patients with IgE-Mediated Hypersensitivity to Penicillins

BACKGROUND

Studies performed since 1990 on samples of at least 30 subjects with a documented IgE-mediated hypersensitivity to penicillins have found a rate of positive responses to allergy tests with cephalosporins ranging from 0% to 27%.

OBJECTIVE

We sought to assess the cross-reactivity with cephalosporins and evaluate the possibility of using cephalosporins in penicillin-allergic subjects.

METHODS

We conducted a prospective study of 252 consecutive subjects who had suffered 319 immediate reactions (mostly anaphylaxis) to penicillins and had positive skin tests to at least 1 penicillin reagent. All patients underwent serum specific IgE assays for cefaclor, as well as skin tests with 3 aminocephalosporins (cephalexin, cefaclor, and cefadroxil), cefamandole, cefuroxime, ceftazidime, ceftriaxone, cefotaxime, and cefepime. Patients with negative results for the last 5 cephalosporins were challenged with cefuroxime axetil and ceftriaxone; those with negative results for aminocephalosporins were also challenged with cefaclor and cefadroxil.

RESULTS

Ninety-nine participants (39.3%) had positive allergy tests for cephalosporins. Specifically, 95 (37.7%) were positive to aminocephalosporins and/or cefamandole, which share similar or identical side chains with penicillins. All 244 subjects who underwent challenges with cefuroxime axetil and ceftriaxone tolerated them. Of the 170 patients who underwent aminocephalosporin challenges, 3 reacted to cefaclor and 4 to cefadroxil.

CONCLUSIONS

Cross-reactivity between penicillins and cephalosporins seems to be mainly related to side chain similarity or identity. Subjects with an IgE-mediated hypersensitivity to penicillins could be treated with cephalosporins such as cefuroxime and ceftriaxone that have side-chain determinants different from those of penicillins and are negative in pretreatment skin testing.

A preliminary investigation of the toxic effects of Benzylpenicilloic acid

Benzylpenicilloic acid (BPNLA) is a major cleavage product of benzylpenicillin G (BP) generated after heating treatment. It is found in animal derived products from the unstable residual penicillin. Previous studies have only reported the allergic reaction caused by BPNLA, but not described its toxicity. In this study, the toxicity of BPNLA was evaluated to report the potential public health risk posed by animal derived products using in vivo and in vitro models, including the acute toxicity assays, cytotoxicity assays, apoptosis assays and cell cycle progression assay. The LD₅₀ value for BPNLA was 8.48 g/kg [bw] intraperitoneally. BPNLA showed cytotoxicity and inhibition of cell proliferation on SK-N-SH cells, MRC-5 cells and GC-1 cells. Further, Annexin-v/PI staining and Hoechst 33342 staining showed increased cell apoptosis and nucleus morphological changes with toxic levels of BPNLA. BPNLA arrested cells in G1 phase and reduced cells population in S phase in a dose-dependent manner. This work suggests that BPNLA might be a potential toxic agent and might have public health significance. However, the toxic concentrations of BPNLA are relatively high compared to levels that would result from the degradation of antibiotics residues in meat from animals that have received a therapeutic dose of benzylpenicillin.

Delayed Allergy to Aminopenicillins: Clinical and Immunological Findings

Aminopenicillins are the most used β-lactam antibiotics. Morbilliform or maculopapular rashes are rather frequent during therapy with aminopenicillins. The pathogenesis of these reactions is often due to a cell-mediated allergy. The aim of this work is to characterize patients with cell-mediated allergy to aminopenicillins and to identify alternative β-lactam drugs that can be safely administered to these patients. We studied 27 subjects affected by cell-mediated allergy to aminopenicillins. The diagnosis was made on the basis of positivity of patch tests with aminopenicillins. These patients then underwent an allergological evaluation (skin and patch tests, oral and/or intramuscular challenge tests) with a wide spectrum of β-lactam antibiotics. Our work highlights the following main characteristics of cell-mediated allergy to aminopenicillins: time elapsing between drug administration and onset of symptoms of about 2 days; the maculopapular rash and delayed appearance of urticaria/angioedema were the most typical symptoms (82.8% of cases); a cross-reactivity with aminocephalosporins is usually absent, or it is limited to cephalexin (in our study, in fact, just 3 out of 20 patients challenged with cephalexin showed a positive oral challenge test); all the β-lactams, other than aminopenicillins, are well tolerated. Patch tests represent a specific diagnostic tool with a good predictive value of identifying alternative drugs that can be safely administered to patients with β-lactam allergy. Our patients could tolerate other β-lactam drugs after a complete allergological evaluation. On the basis of our study, cell-mediated allergy to aminopenicillins should be considered a well-defined nosologic entity.

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.

Anaphylactoid reaction caused by sodium ceftriaxone in two horses experimentally infected by Borrelia burgdorferi

BACKGROUND

Lyme borreliosis is a disease transmitted by ticks to mammals, especially in horses and humans. Caused by a spirochete Borrelia burgdorferi, it can result in lameness, arthritis, carditis, dermatitis and neurological signs. Anaphylactoid reactions are severe responses caused by direct action of substances (drugs, toxins), which can pose risks to life. Still poorly documented in horses, these reactions are caused by the effects of inflammatory mediators such as histamine, kinins and arachidonic acid metabolites. The last two are the most clinically relevant for the species.

CASE PRESENTATION

The simultaneous occurrence of anaphylactoid reaction in two horses experimentally infected by Borrelia burgdorferi undergoing intravenous treatment with ceftriaxone sodium is reported. It was administered 4.7 × 10(8) spirochetes intradermal and subcutaneous applications in both horses to evaluate clinical aspects of the Lyme disease, 95 days before the application of sodium ceftriaxone. During the administration, one horse (a gelding) showed immediate and severe anaphylactoid symptoms such as urticaria, dyspnea, tachycardia, and eyelid edema, which were controlled by injecting dexamethasone. After 1 day, it expressed signs of abdominal discomfort, caused by severe bloat, which was treated surgically via celiotomy. Subsequently, this gelding had piroplasmosis and severe anemia, requiring treatment with an antimicrobial and blood transfusion. Second horse (a mare) showed signs of hypotension during the application of the antibiotic, which disappeared only when the application was interrupted. Days after the event, the mare developed moderate large colon bloat, which was treated with medication only. Subsequently the mare was evolved into the prodromal phase of laminitis in one of the forelimbs, which was treated for 10 days with non-steroidal anti-inflammatory and rheology modifying drugs and cryotherapy.

CONCLUSIONS

From the two cases presented here, it does appear that sodium ceftriaxone can induce anaphylactoid reactions in horses infected by Borrelia burgdorferi, which may evolve into colic syndrome, laminitis and the occurrence of opportunistic infections. However, further evidence should be collected in order to draw definite conclusions.

Hypersensitivity Pneumonitis Caused by Cephalosporins With Identical R1 Side Chains

Drug-induced hypersensitivity pneumonitis results from interactions between pharmacologic agents and the human immune system. We describe a 54-year-old man with hypersensitivity pneumonitis caused by cephalosporins with identical R1 side chains. The patient, who complained of cough with sputum, was prescribed ceftriaxone and clarithromycin at a local clinic. The following day, he complained of dyspnea, and chest X-ray revealed worsening of inflammation. Upon admission to our hospital, antibiotics were changed to cefepime with levofloxacin, but his pneumonia appeared to progress. Changing antibiotics to meropenem with ciprofloxacin improved his symptoms and radiologic findings. Antibiotics were de-escalated to ceftazidime with levofloxacin, and his condition improved. During later treatment, he was mistakenly prescribed cefotaxime, which led to nausea, vomiting, dyspnea and fever, and indications of pneumonitis on chest X-ray. We performed bronchoalveolar lavage, and the findings included lymphocytosis (23%), eosinophilia (17%), and a low cluster of differentiation (CD) 4 to CD8 ratio (0.1), informing a diagnosis of drug-induced pneumonitis. After a medication change, his symptoms improved and he was discharged. One year later, he was hospitalized for acute respiratory distress syndrome following treatment with ceftriaxone and aminoglycosides for an upper respiratory tract infection. After steroid therapy, he recovered completely. In this patient, hypersensitivity reaction in the lungs was caused by ceftriaxone, cefotaxime, and cefepime, but not by ceftazidime, indicating that the patient's hypersensitivity pneumonitis was to the common R1 side chain of the cephalosporins.

Beta-Lactam Hypersensitivity and Cross-Reactivity

Penicillin is the most frequently reported cause of drug allergy, and cross-reactivity of penicillins with other beta-lactam antibiotics is an area of debate. This review evaluates the available data on immunoglobulin E-mediated penicillin hypersensitivity and cross-reactivity with cephalosporin, carbapenem, and monobactam antibiotics. A MEDLINE search was conducted from 1950 to October 2013, and selected references from review articles were also evaluated. There is a wide variety in reported incidences of cross-reactivity between penicillins and cephalosporins or carbapenems, with early retrospective studies suggesting up to 41.7% and 47.4% cross-reactivity, respectively. Conversely, the use of monobactam antibiotics is frequently employed in the case of a penicillin allergy, as prescribers believe that there is no cross-reactivity between the 2 drug classes. More recent prospective studies suggest that the rates of cross-reactivity with cephalosporins and carbapenems are <5% and <1%, respectively. Similarities in penicillin and cephalosporin side chains may play a role in cross-reactivity between these classes. Cross-reactivity with monobactams is essentially negligible; however, there are some clinical data to support an interaction between ceftazidime and aztreonam, due to the similarity of their side chains. The data reviewed suggest that avoidance of other beta-lactams in patients with type 1 hypersensitivity to penicillins should be reconsidered.

[Allergies to antibiotic drugs: their importance in otorhinolaryngology]

BACKGROUND

In 2009, over 40 million prescriptions for antibiotic drugs were counted in outpatient medical care in Germany. This represents a turnover of more than 750 million euros. With over 80 million daily defined doses (DDD), amoxicillin was the most frequently prescribed antibiotic in Germany in 2008. Given the average of 5775 DDD per doctor, otolaryngologists prescribed more antibiotics than specialists in any other field of medicine in 2008; approximately 82% of these were β-lactams and tetracyclines.

MATERIAL AND METHODS

This article is based on selective literature-based research using the PubMed database. The keywords used in the search were:"allergy","anaphylaxis" and"hypersensitivity", in combination with "penicillin","cephalosporin","carbapenem","cotrimoxazole","macrolide","aztreonam" and"tetracycline".

RESULTS

Allergic reactions to antibiotics are among the most frequently reported adverse side effects arising from drug treatment. However, non-allergic adverse side effects owing to drug intolerance are also very common and may be clinically indistinguishable from allergic reactions. Owing to a frequent lack of appropriate diagnostic investigation, the decision to withhold effective standard treatments from patients is often based solely upon anamnestic observations. Up to 10% of respondents in an unselected population report an allergy to penicillin. In 80% of these cases, however, no penicillin-specific IgE-antibodies can be detected.

CONCLUSION

A detailed understanding of the symptoms, diagnostic options and possible cross reactions pertaining to allergic reactions to antibiotics, as well to non-allergic adverse side effects with similar clinical appearance, is very important for otolaryngologists. This profound knowledge ensures that the correct diagnostic steps are taken and that appropriate treatment decisions prevent the unnecessary use of reserve antibiotics.

Baboon syndrome: an unusual complication arising from antibiotic treatment of tonsillitis and review of the literature

A 40-year-old man presented with sore throat and fevers associated with bilaterally enlarged and inflamed tonsils. A clinical diagnosis of tonsillitis was made and the patient received intravenous benzylpenicillin. Over subsequent days, the patient developed a macular rash over both groins, buttocks and axillae, with necrotic patches in the groins. An assumptive diagnosis of necrotising fasciitis was made. The patient underwent urgent groin biopsy and was started on broad spectrum antibiotics. No organisms were seen on Gram stain. Following a multidisciplinary discussion, the patient was diagnosed with baboon syndrome (symmetrical drug-related intertriginous and flexural exanthema). He was treated with oral steroid along with topical agents. Baboon syndrome can develop following penicillin administration. Given the widespread use of penicillin antibiotics to treat tonsillitis and many other conditions, it is important that medical staff recognise the side effects of these medications.

Educational case series: Mechanisms of drug allergy

Once administered, a drug can activate the immune system by various mechanisms and lead to a large range of clinical manifestations closely related to the type of immune reaction elicited. Administration of the drug can classically result in an immunoglobulin E (IgE)-type sensitization, but can also result in more complex activation of the immune system potentially resulting in severe syndromes, such as the drug-induced hypersensitivity syndrome (DIHS). Although there has been a major increase in our knowledge over the last years, the exact mechanisms of drug allergy are not well understood for most clinical manifestations. A complex interaction between individual characteristics, environmental factors, and the drug itself is usually responsible for adverse reactions to drugs. In this educational review series, we described three cases of drug allergy: first, a child with a typical IgE-mediated drug allergy, second, a child with a non-immediate reaction to penicillin, and in the third patient, we will discuss the drug-induced hypersensitivity syndrome, which is rare but potentially fatal. These cases are correlated to the immune mechanism potentially involved.

IgE-mediated hypersensitivity to cephalosporins: cross-reactivity and tolerability of penicillins, monobactams, and carbapenems

BACKGROUND

There have been few studies regarding the cross-reactivity and tolerability of penicillins, aztreonam, and carbapenems in large samples of subjects with cephalosporin allergy.

OBJECTIVE

We sought to evaluate the possibility of using penicillins, monobactams, and carbapenems in subjects with cephalosporin allergy who especially require them.

METHODS

We conducted a prospective study of 98 consecutive subjects who had 106 immediate reactions (mostly anaphylactic shock) to cephalosporins and had positive skin test results for these drugs. To assess the cross-reactivity with penicillins, monobactams, and carbapenems and the tolerability of such alternative β-lactams, all subjects underwent skin tests and serum-specific IgE assays with penicillin reagents, as well as skin tests with aztreonam, imipenem/cilastatin, and meropenem. Subjects with negative test results were challenged with meropenem, imipenem/cilastatin, aztreonam, and amoxicillin.

RESULTS

Positive allergologic test results to penicillins were displayed by 25 (25.5%) subjects, including 1 with positive results to all reagents tested and another with a positive result to aztreonam. Another subject had positive results to both ceftazidime and aztreonam. A reaction to cephalosporins with side-chain structures similar or identical to those of penicillins was a significant predictor of cross-reactivity because of an increased 3-fold risk of positive results on allergologic tests with penicillin determinants. Challenges with alternative β-lactams were tolerated, with the exception of 1 urticarial reaction to imipenem/cilastatin.

CONCLUSIONS

About 25% of subjects with cephalosporin allergy had positive results to penicillins, 3.1% to aztreonam, 2% to imipenem/cilastatin, and 1% to meropenem. In those who especially require alternative β-lactams, pretreatment skin tests are advisable because negative results indicate tolerability of the β-lactam concerned.

Allergic Cross-Sensitivity Between Penicillin, Carbapenem, and Monobactam Antibiotics: What are the Chances?

Objective:

To evaluate the literature on the allergic cross-reactivity between penicillin, carbapenem, and monobactam antibiotics.

Data Sources:

A MEDLINE search (1950–June 2008) of the English literature was performed using the search terms β-lactam, penicillin, monobactam, carbapenem, allergy, and cross-reactivity. References of review articles were also screened for inclusion.

Study Selection and Data Extraction:

All articles in English from the data source were identified. Studies whose primary goal was to evaluate drug hypersensitivity and the potential for cross-reactivity were evaluated.

Data Synthesis:

Many patients have reported penicillin allergies that have not been verified by skin testing; many healthcare providers avoid the use of other β-lactam antibiotics, namely carbapenems, in these patients due to fear of the potential for immunoglobulin E-mediated allergic cross-reactivity. A wide range of cross-reactivity between penicillins and carbapenems has been reported in various studies; however, more recent prospective studies have shown the incidence of cross-reactivity between penicillin and carbapenem skin tests to be around 1%. Additionally, many prescribers freely use the monobactam aztreonam in penicillin-allergic patients, believing there is no cross-reactivity between the 2 drugs. Although data support the lack of cross-reactivity between aztreonam and penicillins, immunology and some clinical data support an interaction between ceftazidime and aztreonam due to the similarity of their side chains.

Conclusions:

Although variability in cross-reactivity rates between β-lactam classes exists in the literature, the practice of avoiding carbapenems in penicillin-allergic patients should be reconsidered. With regard to monobactams, the administration of aztreonam in a patient with a ceftazidime allergy may carry an increased risk of type 1 hypersensitivity reactions and should be considered with caution. Additionally, the importance of obtaining a thorough patient history regarding the previous allergic event, proper documentation, and penicillin skin testing is re emphasized.

Antibiotic allergy: immunochemical and clinical considerations

Antibiotics are among the most widely and heavily prescribed drugs, but despite this, allergic reactions to most groups of antibiotics are relatively uncommon-especially when compared with the number and frequency of type 1 hypersensitivity responses to the beta-lactams (ie, penicillins, cephalosporins, and, to a lesser extent, carbopenems). Still, there remains a steady flow of reports of allergic reactions to some topically used antibiotics (eg, rifamycin SV and bacitracin). Moreover, aminoglycosides (eg, neomycin and gramicidin) may be implicated more often than previously suspected. Despite advances in our understanding of the structural basis of the allergenicity of beta-lactam antibiotics, the insights have not readily transferred into routine use to improve diagnoses of reactions to individual penicillins and cephalosporins. This remains a challenge in drug allergy, as does the need for further chemical, immunologic, and clinical research on cephalosporin breakdown products and the so-called multiple antibiotic allergy syndrome.

Clinical presentation and time course in hypersensitivity reactions to beta-lactams

BACKGROUND

beta-lactam hypersensitivity reactions are classified as immediate or nonimmediate. Diagnosis is usually based upon skin tests and provocation challenges.

OBJECTIVE

The time course of the reactions in proven beta-lactam hypersensitivities was studied and then correlated with the symptoms to determine the relationship between the clinical presentations and the time course.

METHOD

All of the patients who consulted between 1996 and 2004 for a suspected beta-lactam hypersensitivity reaction were studied. Two hundred and ten patients with a proven hypersensitivity reaction diagnosed according to the European Network on Drug Allergy were included in the present study.

RESULTS

Of the patients, 36.7% had urticaria as a single symptom, 19.1% anaphylaxis without shock, 17.6% anaphylactic shock and 19.1% maculopapular exanthema. Anaphylactic shock and anaphylaxis mostly occurred within 1 h after drug administration. Exanthema mainly occurred after 24 h. Urticaria as a single symptom occurred at any time. A firm diagnosis was determined using immediate-reading skin prick (10.0%) and intradermal tests (38.1%), late-reading skin tests (19.1%) or provocation tests (32.9%).

CONCLUSION AND CLINICAL IMPLICATION

Depending on the time course of the reaction, three clinical groups were identified: anaphylaxis and anaphylactic shock (immediate reaction); maculopapular exanthema (late reaction) as well as urticaria (immediate and late reaction).

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.

Use of selected cephalosporins in penicillin-allergic patients: a paradigm shift

Recent analysis of clinical data and a clearer understanding of the role of chemical structure in the development of cross-reactivity indicate that the increased risk of an allergic reaction to certain cephalosporins in penicillin-allergic patients is smaller than previously postulated. Medline and EMBASE databases were searched using the following keywords: cephalosporin, penicillin, allergy, and cross-sensitivity for the years 1960 to 2005. Among 219 articles retrieved, 106 served as source material for this review. A significant increase in allergic reactions to cephalothin, cephaloridine, cephalexin, cefazolin, and cefamandole was observed in penicillin-allergic patients; no increase was observed with cefprozil, cefuroxime, ceftazidime, or ceftriaxone. Clinical challenges, skin testing, and monoclonal antibody studies point to the paramount importance of similarities in side chain structure to predict cross-allergy between cephalosporins and penicillins. First-generation cephalosporins have a modest cross-allergy with penicillins, but cross-allergy is negligible with 2nd- and 3rd-generation cephalosporins. Particular emphasis is placed on the role of chemical structure in determining the risk of cross-reactivity between specific agents.

Relevance of the determination of serum-specific IgE antibodies in the diagnosis of immediate beta-lactam allergy

BACKGROUND

Allergic reactions to beta-lactams are the most frequent cause of adverse drug reactions mediated by specific immunologic mechanisms. They can be explored by in vivo and/or in vitro tests. The measurement of serum-specific immunoglobulin E (IgE) presents several advantages: safety, simplicity, and availability to nonallergologist physicians.

OBJECTIVES

To establish the diagnostic value of specific IgE determination in the diagnosis procedure of immediate beta-lactam allergy.

METHODS

The in vitro determination of beta-lactam-specific IgE antibodies was compared in three well-defined groups of patients (n=45): one with negative skin tests and a positive drug provocation test, another with positive skin tests, and a third control exposed population with good tolerance. Two techniques were used: the CAP-FEIA system (Phadia) commercially available and a homemade radioallergosorbent test (RAST).

RESULTS

The specificity of CAP-FEIA ranged from 83.3% to 100% and sensitivity from 0% to 25% depending on initial clinical manifestations. The specificity of RAST was between 66.7% and 83.3% and sensitivity 42.9% and 75%. In the subgroup of patients with an anaphylactic shock and negative skin tests, the sensitivity and specificity of RAST were 75%. Positive and negative predictive values were 45.5% and 77.1% with CAP-FEIA and 38.5% and 81.5% with RAST, respectively.

CONCLUSION

These results indicate that, although the specificity of beta-lactam-specific IgE measurement is good, sensitivity is low. Immunoglobulin E measurement should be limited to patients with a clinical history of anaphylactic shock and negative skin tests in order to avoid a drug provocation test. More sensitive assays should be developed.

Immediate allergic reactions to cephalosporins: evaluation of cross-reactivity with a panel of penicillins and cephalosporins

BACKGROUND

Allergy to cephalosporins has mainly been evaluated in the context of patients with confirmed penicillin allergy. The problem of studying cross-reactivity in subjects primarily sensitized to cephalosporins and potentially allergic to penicillins has not been sufficiently addressed.

OBJECTIVE

To evaluate the in vitro IgE response and cross-reactivity to betalactams in patients with immediate allergic reactions to cephalosporins.

METHODS

The study included 24 patients with immediate allergic reactions to cephalosporins and RAST-positive to at least 1 cephalosporin. Skin testing and RAST were performed with a panel of penicillins and cephalosporins. RAST inhibition assay with different monomeric conjugates of penicillin and cephalosporin was performed to establish cross-reactivity.

RESULTS

The culprit cephalosporins were cefaclor (N = 7), cefonicid (N = 1), cefotaxime (N = 2), ceftazidime (N = 2), ceftriaxone (N = 3), and cefuroxime (N = 9). Two patients had a positive skin test result to penicillin determinants, and 22 patients had a negative result to penicillin determinants and tolerated benzylpenicillin administration. Of these 22, 19 had a positive skin test result to cephalosporins and divided into patients reacting only to the culprit cephalosporin (63.2%) and those reacting to more than 1 cephalosporin (36.8%). RAST and RAST inhibition studies confirmed that the side chain at the R1 position is crucial for recognition.

CONCLUSION

The R1 side chain rather than the betalactam structure, shared by penicillins and cephalosporins, seems to play a dominant role in determining the specificity of immunologic reactions to cephalosporins. Thus, penicillin can be administered safely to patients allergic to cephalosporins and with a negative skin test result to penicillin determinants.

Allergic reactions to beta-lactams

Allergy to beta-lactam antibiotics is the most frequent cause of drug-induced immunological reactions, although the prevalence is not exactly known. IgE- and T-cell-dependent responses are the main mechanisms involved, although other immunological mechanisms can also participate, especially in haematological abnormalities, such as immune haemolytic anaemia or thrombocytopoenia. Aside from their frequency, the clinical entities reported nowadays have changed little since penicillin was first used. The variation in beta-lactams consumption through the year has modified the pattern and specificities of allergic reactions for IgE and T cell responses. Benzylpenicillin is no longer the beta-lactams most frequently prescribed and other chemical structures, with new or modified haptens, have progressively replaced it. This is relevant for the diagnostic evaluation and management of beta-lactam hypersensitivity.

Diagnosing immediate reactions to cephalosporins

BACKGROUND

After penicillins, cephalosporins are the betalactams that most often induce IgE-mediated reactions. The development of diagnostic tests has been delayed, however, because the cephalosporin allergenic determinants have not been properly identified.

OBJECTIVE

To evaluate the usefulness of skin tests, serum specific IgE assays, and challenges in diagnosing immediate reactions to cephalosporins and to clarify the pathogenic mechanism of such reactions.

METHODS

We studied 76 adults with immediate reactions to cephalosporins, mainly ceftriaxone, cefotaxime, and ceftazidime. Skin tests and serum specific IgE assays were performed for culprit cephalosporins and cefaclor, as well as for penicillin, amoxicillin, and ampicillin. Some subjects with negative results underwent challenges and re-evaluations. Responses to cephalosporins other than the culprit ones were also studied.

RESULTS

In the first allergologic work-up, an IgE-mediated hypersensitivity to penicillins and/or cephalosporins was diagnosed in 63 (82.9%) of the 76 patients on the basis of skin-test and/or specific IgE assay positivity. Of the 13 negative patients, eight accepted challenges and underwent re-evaluations. Considering both first- and second-evaluation results, the skin-test-positivity rate increased from 76.3% to 85.5% and that of sepharose-radioimmunoassay positivity from 67.1% to 74.3%. Overall, an IgE-mediated hypersensitivity was diagnosed in 70 patients (in seven after retesting). On the basis of skin-test and CAP-FEIA results, we classified our 76 patients into five groups: group A (three patients), positive only to penicillin reagents; B (17), positive to both cephalosporin and penicillin reagents; C (24), positive to more than one cephalosporin; D (21), positive only to the responsible cephalosporin; E (11) negative to skin tests and CAP-FEIA, including five sepharose-radioimmunoassay positive.

CONCLUSIONS

Most immediate reactions to cephalosporins appear to be IgE-mediated. Cephalosporin skin testing and sepharose-radioimmunoassay are useful tools for evaluating these reactions. Cephalosporin IgE-mediated hypersensitivity may be a transient condition; therefore, allergologic exams should be repeated in patients with negative initial allergologic work-ups, including challenges.

Decrease of selective immunoglobulin E response to amoxicillin despite repeated administration of benzylpenicillin and penicillin V

BACKGROUND

Subjects with IgE responses to betalactams can develop selective or cross-reactive responses after the administration of penicillin derivatives. After the reaction, however, the hapten induces a boosting phenomenon, which may increase the titre and the affinity of the antibody, with the resulting risk of developing allergic reactions to other penicillins.

OBJECTIVE

To determine in subjects with selective responses to amoxicillin (AX) and good tolerance to benzylpenicillin (BP) and penicillin V (PV) whether the administration of these compounds induced any change in specificity, measured by either skin or in vitro testing, which could predict the appearance of cross-reactivity.

METHODS

Ten subjects with a selective response to AX were followed-up for 2 years with the periodic administration of penicillin G and V (Group A) and compared with another group composed of 10 persons with identical clinical characteristics but without repeated penicillin administration (Group B). Periodic in vitro and in vivo measurements of specific IgE antibodies were performed at 6-month intervals. Patients were randomized to Group A or B according to their order of inclusion.

RESULTS

In both groups, skin test reactivity tended to decrease, and although greater in Group A, the difference was not significant compared with Group B. Median RAST values also decreased over time and showed no differences in the exposed group compared with the controls. One patient in Group A became positive to benzylpenicilloyl (BPO), despite becoming negative to AX.

CONCLUSION

Subjects with selective IgE responses to side-chain-specific determinants seem to become negative, with no influence from subsequent administration of a closely related penicillin.

Differential effects of beta-lactams on human IFN-gamma activity

OBJECTIVES

To investigate whether a range of beta-lactam antibiotics conjugate to and hence reduce the activity of IFN-gamma, as has been shown for penicillin G. A selection of penicillins, cephalosporins, a monobactam (aztreonam), a beta-lactamase inhibitor (clavulanic acid), a carbapenem (meropenem) and the non-beta-lactam penicillin derivative d-penicillamine were tested for their effect on IFN-gamma activity.

METHODS

Following exposure to a range of concentrations of these compounds, for varying lengths of time, IFN-gamma activity was assayed by induction of CD54 on the surface of the lung epithelial cell line A549, utilizing an ELISA.

RESULTS

Clavulanic acid, cefoxitin and cefaloridine were the most potent inhibitors of IFN-gamma activity, followed by cefotaxime, ceftriaxone and phenoxymethylpenicillin. Ampicillin was less inhibitory than penicillin G, whilst meropenem and aztreonam had the least effect and d-penicillamine had no effect. The modulatory effect of these compounds was not due to a direct effect on CD54 induction. Unlike freshly prepared drugs, aged preparations of penicillin G and clavulanic acid had no significant effect on IFN-gamma activity.

CONCLUSIONS

beta-Lactams differ in their capacity to modulate human IFN-gamma activity. This finding may have implications for the immunomodulatory effects of beta-lactams and for the design both of beta-lactams that do not affect the immune system and those which may be used therapeutically to target cytokine action.

Heterogeneity of the IgE response to allergenic determinants of cefaclor in serum samples from patients with cefaclor-induced anaphylaxis

BACKGROUND

Beta-lactam antibiotics, such as cefaclor, may cause IgE-mediated anaphylactic reactions. However, the clinically available serologic test has not been widely accepted, and the antigenic determinants of these drugs are unclear.

OBJECTIVE

To describe 4 cases of anaphylaxis caused by cefaclor in which a specific IgE response to cefaclor was demonstrated.

METHODS

Four patients with anaphylaxis to cefaclor and 35 nonatopic controls never exposed to cefaclor were studied. Skin tests and oral challenges with this drug were performed. The specific IgE response to the antigenic determinant of cefaclor-human serum albumin (HSA) conjugate was compared in each patient. The serum specific IgE to cefaclor-HSA conjugate was detected using enzyme-linked immunosorbent assay (ELISA). Also, ELISA inhibition studies using various concentrations of cefaclor-HSA, HSA alone, and free cefaclor were performed, as were hapten inhibition studies using cefaclor, cephalexin, cefadroxil, ampicillin, ceftriaxone, and cefotaxime.

RESULTS

Three patients showed high levels of serum specific IgE to cefaclor-HSA and marked inhibition patterns to free cefaclor and cefaclor-HSA conjugate on ELISA inhibition testing. Hapten inhibition testing in 3 individual serum samples showed 2 different patterns. In patient 3, significant dose-dependent inhibitions (up to 92%) were noted with additions of free cefaclor and cefaclor-HSA conjugate, and lesser inhibitions (up to 74%) were noted with cephalexin, which shares the aminobenzyl side chain. In patients 1 and 2, marked dose-dependent inhibitions were noted only with additions of cefaclor-HSA conjugate and free cefaclor, whereas minimal inhibitions were noted with the other 5 compounds.

CONCLUSIONS

The specific IgE response to cefaclor-HSA conjugate in patients with cefaclor anaphylaxis occurs against the hapten, in which heterogeneity of the antigenic determinant was noted to depend on the individual.