Evaluation of the immunologic cross-reactivity of aztreonam in patients with cystic fibrosis who are allergic to penicillin and/or cephalosporin antibiotics

Nanoparticle-based platforms for targeted drug delivery to the pulmonary system as therapeutics to curb cystic fibrosis: A review

Cystic fibrosis (CF) is a genetic disorder of the respiratory system caused by mutation of the Cystic Fibrosis Trans-Membrane Conductance Regulator (CFTR) gene that affects a huge number of people worldwide. It results in difficulty breathing due to a large accumulation of mucus in the respiratory tract, resulting in serious bacterial infections, and subsequent death. Traditional drug-based treatments face hindered penetration at the site of action due to the thick mucus layer. Nanotechnology offers possibilities for developing advanced and effective treatment platforms by focusing on drugs that can penetrate the dense mucus layer, fighting against the underlying bacterial infections, and targeting the genetic cause of the disease. In this review, current nanoparticle-mediated drug delivery platforms for CF, challenges in therapeutics, and future prospects have been highlighted. The effectiveness of the different types of nano-based systems conjugated with various drugs to combat the symptoms and the challenges of treating CF are brought into focus. The toxic effects of these nano-medicines and the various factors that are responsible for their effectiveness are also highlighted.

Cephalosporin Allergy: Current Understanding and Future Challenges

Cephalosporins are commonly used antibiotics both in hospitalized patients and in outpatients. Hypersensitivity reactions to cephalosporins are becoming increasingly common with a wide range of immunopathologic mechanisms. Cephalosporins are one of the leading causes for perioperative anaphylaxis and severe cutaneous adverse reactions. Patients allergic to cephalosporins tend to tolerate cephalosporins with disparate R1 side chains but may react to other beta-lactams with common R1 side chains. Skin testing for cephalosporins has not been well validated but appears to have a good negative predictive value for cephalosporins with disparate R1 side chains. In vitro tests including basophil activation tests have lower sensitivity when compared with skin testing. Rapid drug desensitization procedures are safe and effective and have been used successfully for immediate and some nonimmediate cephalosporin reactions. Many gaps in knowledge still exist regarding cephalosporin hypersensitivity.

β-Lactams and β-Lactamase Inhibitors: An Overview

β-Lactams are the most widely used class of antibiotics. Since the discovery of benzylpenicillin in the 1920s, thousands of new penicillin derivatives and related β-lactam classes of cephalosporins, cephamycins, monobactams, and carbapenems have been discovered. Each new class of β-lactam has been developed either to increase the spectrum of activity to include additional bacterial species or to address specific resistance mechanisms that have arisen in the targeted bacterial population. Resistance to β-lactams is primarily because of bacterially produced β-lactamase enzymes that hydrolyze the β-lactam ring, thereby inactivating the drug. The newest effort to circumvent resistance is the development of novel broad-spectrum β-lactamase inhibitors that work against many problematic β-lactamases, including cephalosporinases and serine-based carbapenemases, which severely limit therapeutic options. This work provides a comprehensive overview of β-lactam antibiotics that are currently in use, as well as a look ahead to several new compounds that are in the development pipeline.

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.

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.

Aztreonam lysine for inhalation: new formulation of an old antibiotic

PURPOSE

The pharmacology, safety, efficacy, pharmacokinetics, pharmacodynamics, current place in therapy, and potential future therapeutic uses of inhaled aztreonam are reviewed.

SUMMARY

Inhaled aztreonam, a newly formulated lysine salt of the original monobactam antibiotic, is approved for the treatment of respiratory symptoms in patients with cystic fibrosis (CF) who are colonized with Pseudomonas aeruginosa. Its spectrum of activity is limited to susceptible gram-negative organisms, including P. aeruginosa. Lyophilized aztreonam lysine is diluted with 0.17% sodium chloride and administered using the Altera nebulizer system, which produces appropriate-sized particles for proper deposition in the lungs to achieve high sputum and low systemic concentrations. Mean sputum drug concentrations are highest 10 minutes after dose administration, and plasma concentrations peak one hour after inhalation. Aztreonam is excreted via active tubular secretion and glomerular filtration. Caution is advised in patients with renal or hepatic impairment, breastfeeding women, and patients age 65 years or older. Like the older i.v. formulation, inhaled aztreonam displays time-dependent killing. Phase III clinical trials have shown improvements in respiratory symptoms, decreased P. aeruginosa sputum density, prolonged time intervals between antibiotic treatments, and efficacy without the development of resistance in the face of repeated exposures. This formulation is available only from select specialty pharmacies and should only be used with the Altera nebulizer system.

CONCLUSION

Inhaled aztreonam has shown efficacy and safety in patients seven years of age or older with CF who have P. aeruginosa airway infections. This product may complement existing therapies and offers the advantage of a new inhaled formulation to aid in treatment regimens.

Use of empiric antimicrobial therapy in neutropenic fever. Australian Consensus Guidelines 2011 Steering Committee

Administration of empiric antimicrobial therapy is standard practice in the management of neutropenic fever, but there remains considerable debate about the selection of an optimal regimen. In view of emerging evidence regarding efficacy and toxicity differences between empiric treatment regimens, and strong evidence of heterogeneity in clinical practice, the current guidelines were developed to provide Australian clinicians with comprehensive guidance for selecting an appropriate empiric strategy in the setting of neutropenic fever. Beta-lactam monotherapy is presented as the treatment of choice for all clinically stable patients while early treatment with combination antibiotic therapy is considered for patients at higher risk. Due consideration is given to the appropriate use of glycopeptides in this setting. Several clinical caveats, accounting for institution- and patient-specific risk factors, are provided to help guide the judicious use of the agents described. Detailed recommendations are also provided regarding time to first dose, timing of blood cultures, selection of a first-line antibiotic regimen, subsequent modification of antibiotic choice and cessation of therapy.

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.

Usefulness of serum IgG4 in the diagnosis and follow up of autoimmune pancreatitis: A systematic literature review and meta-analysis

High circulating serum immunoglobulin G4 (IgG4) levels have been proposed as a marker of autoimmune pancreatitis (AIP). The aim of the present study was to review the data existing in the English literature on the usefulness of the IgG4 serum levels in the diagnosis and follow up of patients with AIP. A total of 159 patients with AIP and 1099 controls were described in seven selected papers reporting the usefulness of serum IgG4 in diagnosing AIP. In total, 304 controls had pancreatic cancer, 96 had autoimmune diseases, and the remaining 699 had other conditions. The summary receiver-operating characteristic curve analysis was carried out by means of Meta-DiSc open-access software. Serum IgG4 showed good accuracy in distinguishing between AIP and the overall controls, pancreatic cancer and other autoimmune diseases (area under the curve [+/- SE]: 0.920 +/- 0.073, 0.914 +/- 0.191, and 0.949 +/- 0.024, respectively). The studies analyzed showed significantly heterogeneous specificity values in each of the three analyses performed. The analysis of the four studies comparing AIP and pancreatic cancers also showed significantly heterogeneous values of sensitivities and odds ratios. Regarding the usefulness of IgG4 as a marker of efficacy of steroid treatment, a decrease in the serum concentrations of IgG4 was found in the four available studies. The serum IgG4 subclass is a good marker of AIP, and its determination should be included in the diagnostic workup of this disease. However, the heterogeneity of the studies published until now means that more studies are necessary in order to better evaluate the true accuracy of IgG4 in discriminating AIP versus other autoimmune diseases.

Beta-lactam allergy in adults with cystic fibrosis

BACKGROUND

Allergic reactions to one or more beta-lactam antibiotic can pose a management problem in patients with cystic fibrosis (CF), and may limit antibiotic choice.

METHOD

The aim of this study was to assess the prevalence of allergy to anti-pseudomonal beta-lactam antibiotics in an adult CF centre and to assess variables, which may contribute to the development of allergic reactions. A questionnaire-based interview and a review of medical records were performed.

RESULTS

Of the 150 patients, 54 (36%) had allergic reactions to one or more beta-lactam antibiotics and 20 (19%) had allergic reactions to multiple beta-lactam antibiotics. The proportion of patients allergic to specific beta-lactam antibiotics varied from 10% to 26%. Rates of reactions were highest for penicillins and cephalosporins, intermediate for carbepenems and lowest for aztreonam. Of all reactions, 40% occurred within 24 h of the commencement of an individual antibiotic course. Patients with one or more beta-lactam allergic reactions had received greater cumulative exposure (p<0.0001), were older (p=0.016) and had lower lung function (p=0.037) than patients without a history of beta-lactam allergy. Cystic Fibrosis transmembrane regulator (CFTR) status, gender, peripheral blood eosinophil count and total IgE concentrations were not different in patients with allergic reactions.

CONCLUSIONS

This study demonstrates that the prevalence of allergic reactions to beta-lactam antibiotics is high in adults with CF. Increasing age; cumulative exposure and decreasing FEV(1) were associated with the development of allergy.

Antibiotic allergy in cystic fibrosis

Allergic reactions to antibiotics are more common in cystic fibrosis (CF) than in the general population. This in part is due to the improving survival in adults with CF and the increased use of high dose intravenous antibiotics. While some are immediate anaphylaxis type (IgE mediated) reactions, the majority are late onset and may have non-specific features such as rash and fever. Piperacillin has consistently been found to have the highest rate of reported reactions (30-50%). There is a low risk of cross reactions between penicillins and other non-beta-lactam classes of antibiotics in penicillin skin prick positive patients. Carbapenems should only be used with extreme caution in patients with positive skin prick tests to penicillin. However, aztreonam can be used safely in patients who are penicillin allergic with positive skin prick reactions. The aminoglycosides are a relatively uncommon cause of allergic reactions, but patients who react to one member of the family may cross react with other aminoglycosides. Desensitisation relies on the incremental introduction of small quantities of the allergen and has been used for penicillins, ceftazidime, tobramycin and ciprofloxacin and must be repeated before each course. Personalized cards should be regularly updated for patients who develop allergic reactions. Written instructions on the emergency treatment of allergic reactions should be provided to patients self-administering intravenous antibiotics at home. Further research is required to identify risk factors and predictors for antibiotic allergy.

Antimicrobial agents for the dermatologist. I. Beta-lactam antibiotics and related compounds

We review the newer antimicrobial agents that are being employed by dermatologists with increased frequency as well as some of the more commonly used older agents. Particular emphasis is based on selection factors such as causative pathogens and their resistance profiles, routes of administration, toxicity, drug interactions, and dosing requirements. Emphasis in this review is on the newer classes of antimicrobials such as third- and fourth-generation cephalosporins; beta-lactam, beta-lactamase inhibitor combination agents; monobactams; carbapenems; macrolides; and fluoroquinolones. Dermatologic indications and treatment alternatives are highlighted; this will expand the practicing clinician's therapeutic armamentarium and enable him/her to make rational decisions concerning treatment approaches to infectious disease problems encountered in daily practice.

Increasing dose regimen in children with reactions to ceftazidime

BACKGROUND

Of 87 consecutive patients with cystic fibrosis treated with 859 courses of intravenous ceftazidime, 15 patients experienced reactions to drugs.

OBJECTIVE

To see if by varying the means of administration further courses of treatment with ceftazidime could be tolerated in subjects who had experienced drug reactions.

METHODS

Starting with a dose of 1 mg per hour, and doubling the dose every hour, ceftazidime was administered at increasing dosage by continuous infusion, reaching a rate of 150-300 mg/kg/day. Thereafter the full daily dose was given in three divided bolus doses. For patients who tolerated the maximum infusion rate but reacted adversely to bolus doses, the procedure was restarted, and once the normal daily dose rate had been achieved, treatment was completed by continuous intravenous infusion rather than bolus doses.

RESULTS

Of the 15 patients, three patients with urticaria and four patients with nonurticarial itchy rash tolerated further courses of ceftazidime without adverse reactions, and two patients have not had further treatment with intravenous antibiotics. The increasing dose regimen was tolerated in five of the remaining six patients, and further courses of treatment were tolerated in the four patients in whom this was required. One patient had recurrent urticaria despite three attempts at using the regimen, and treatment was given with alternative antibiotics.

CONCLUSION

A continuous drug infusion regimen of starting at a very low dosage and then increasing the dosage offers the potential for further treatment in some children with cystic fibrosis with adverse reactions to ceftazidime.

Allergy to beta-lactams: a survey of current practices

Many issues related to the diagnosis and management of beta-lactam drug allergy still await definitive recommendations. To determine how practicing allergists deal with some of these dilemmas, a questionnaire was mailed to 3500 physician members and fellows of the American Academy of Allergy and Immunology. It was also sent to each of the allergy training program directors in the United States to determine what is currently taught to fellows in training. Benzylpenicilloyl-polylysine (Pre-Pen) and fresh penicillin G are used for skin testing by more than 86% of both respondent groups, whereas minor determinant mixtures are used by only 40%. Epicutaneous followed by intradermal injection was the skin test technique used by 86% of these allergists. More than 90% said they would skin test in cases of reaction history of urticaria, whereas only 1.5% would test in cases of family history of penicillin allergy. Practicing allergists and program directors differed slightly when queried about cephalosporin cross-reactivity. Program directors were more cautious in their use of cephalosporins with patients allergic to penicillin. Program directors were also more likely to repeat skin testing before future penicillin courses than were practicing allergists. Clearly, some individual approaches to the diagnosis and management of beta-lactam allergy are practiced. Development of practice guidelines by our professional organizations may be useful.