Macrolide Allergic Reactions

In silico screening and synthesis of stable tilmicosin-hydrazone derivatives as potential DNA disruptors towards Staphylococcus aureus

In this study, 30 tilmicosin-hydrazone derivatives were designed using MOE software. Six candidate molecules with strong binding affinity to DNA or DNA-Topo II complexes, as indicated by molecular docking results, were synthesized. These candidates were evaluated for their in vitro antibacterial activities against common Gram-positive and Gram-negative bacteria. Compounds Z-12 and Z-22 demonstrated superior inhibitory effects against most tested strains compared to reference drugs tilmicosin and erythromycin, with minimum inhibitory concentrations (MIC) of 1 μg/mL against S. aureus 25,923 and S. aureus 29,213. HPLC results indicated that Z-12 and Z-22 exhibited improved stability in acidic aqueous solutions compared to tilmicosin. UV-vis, fluorescence spectroscopy, and gel electrophoresis studies confirmed their intercalation into DNA base pairs via a static quenching mechanism. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) revealed irreversible oxidation processes on the glassy carbon electrode, providing insights into their potential metabolic pathways. Finally, a mouse wound infection model demonstrated that Z-12 and Z-22 exhibited good antibacterial efficacy, biocompatibility, and enhanced wound healing effects, surpassing those of tilmicosin. These findings, coupled with their prolonged metabolic half-life, highlight their potential as effective antibacterial agents.

Incidence of fidaxomicin allergy in patients with macrolide allergies: a large database analysis

Fidaxomicin may exhibit cross-reactivity in patients with known macrolide allergies. In this analysis, compared to patients without macrolide allergies, the odds of fidaxomicin allergy were 2.31, 8.37, and 1.58 times higher in patients with azithromycin, clarithromycin, and erythromycin allergies, respectively; the absolute risk of fidaxomicin allergy was 0.033, 0.01, and 0.039 in patients with azithromycin, clarithromycin, and erythromycin allergies, respectively. The highest risk of anaphylaxis and angioedema was observed within 1 year of a non-fidaxomicin macrolide allergy.

Management of severe and fulminant Clostridioides difficile infection in adults

Clostridioides difficile (formerly known as Clostridium difficile) is a significant cause of healthcare-associated infection with symptoms ranging from diarrhoea and abdominal pain to pseudomembranous colitis and toxic megacolon. Severe disease can pose a significant morbidity and mortality risk and is to be considered a medical emergency. The emergence of a new C. difficile ribotype with an estimated mortality rate of 20% (ribotype 995) has prompted a re-review of the evidence and guidelines around managing severe C. difficile infections (CDI). International guidance on the management of CDI varies regarding first-line antibiotic choice. Metronidazole is no longer favoured as first line due to concerns around resistance, and vancomycin and fidaxomicin are now recommended as first line options. Antibiotic therapy should be used in conjunction with good supportive measures and early consideration of surgical management. Faecal microbiota transplant can be utilized in recurrent CDI and may be useful in severe disease. Severe CDI is a significant ongoing threat to public health, and further research into effective management is essential to ensure the best possible outcomes for patients.

Age-stratified analysis of adverse event signals for clarithromycin: a disproportionality analysis using the FDA Adverse Event Reporting System

Background

Clarithromycin is a widely used antibiotic, but its safety profile, particularly in different age groups, remains inadequately explored.

Objectives

This study aims to characterize and illustrate the features of clarithromycin-related adverse events (AEs) across different age groups using the FDA Adverse Event Reporting System (FAERS) database, providing a reference for the clinical detection, prevention, and management of AEs in various age groups.

Design

A disproportionality analysis was performed using data from the FAERS database. The study included all AE reports related to clarithromycin, stratified by age groups.

Methods

Disproportionality analysis was conducted using reporting odds ratio, proportional reporting ratio, Bayesian confidence propagation neural network, and multiple gamma Poisson shrinkers. Statistical analyses included descriptive statistics and Chi-square tests.

Results

A total of 7319 reports of clarithromycin AEs were retrieved from the FAERS database. Vomiting, diarrhea, drug interactions, and drug interactions were reported most frequently in the age groups 0-17, 18-44, 45-64, and ⩾65 years, respectively. Abnormal product taste, taste disorder, and medication errors related to drug interactions specified in the package insert were the strongest signals in the age groups 0-17, 18-44, 45-64, and ⩾65 years, respectively. A total of 41 Preferred Terms signals were not explicitly included in the clarithromycin package insert and were mainly associated with psychiatric disorders, skin and subcutaneous tissue disorders, and gastrointestinal disorders, among others. Specific signals for age differences were identified, with 18 signals being age-specific, including 3 in children and 15 in elderly individuals.

Conclusion

The safety profile of clarithromycin varies across age groups. In children, it is mainly associated with vomiting, hypersensitivity, and dyspnea, while in adults, psychiatric AEs are more common. In the elderly, clarithromycin should be used cautiously, with attention to drug interactions.

Structure Elucidation and Interaction Dynamics of MefA-MsrD Efflux Proteins in Streptococcus pneumoniae: Impact on Macrolide Susceptibility

Macrolides are empirically used to treat bacterial community-acquired pneumonia (CAP). Streptococcus pneumoniae, being the major pathogen responsible for bacterial CAP with high mortality rates, express MefA-MsrD efflux pumps to hinder macrolide susceptibility. Despite its importance, the structural features of the efflux-protein complex and its impact on macrolide susceptibility have not yet been elucidated explicitly. Therefore, in the present study, combining homology, threading, and dynamics approaches, MefA and MsrD proteins in pathogenic S. pneumoniae were modeled. Both membrane (lipid-bilayer) and cytoplasmic (aqueous) environments were considered to simulate the MefA and MsrD proteins in their ideal cellular conditions followed by dynamics analyses. The simulated MefA structure represented a typical major facilitator superfamily protein structure with 13 transmembrane helices. MefA-MsrD interaction via clustering-based docking revealed low-energy conformers with stable intermolecular interactions. The higher clinical MIC value of azithromycin over erythromycin was reflected upon erythromycin eliciting stronger interactions (dissociation constant or ki = ∼52 μM) with the cytoplasmic ATP-binding MsrD than azithromycin (ki = ∼112 μM). The strong (binding energy = -132.1 ± 9.5 kcal/mol) and highly stable (root-mean-square fluctuation < 1.0 Å) physical association between MefA with MsrD was validated and was found to be unaffected by the antibiotic binding. Higher propensity of the macrolides to interact with MsrD than MefA established the importance of the former in macrolide susceptibility. Ours is probably the first report on the structural arrangements in the MefA-MsrD efflux complex and the macrolide susceptibility in S. pneumoniae. This study provides a novel lead for experimental explorations and efflux-pump inhibitor designs.

Fidaxomicin-Associated Hypersensitivity Reactions: Report of a Morbilliform Drug Eruption

PurposeWe report a probable case of morbilliform drug eruption secondary to fidaxomicin in a patient with Clostridioides difficile infection (CDI). Summary: A 62-year-old female presented to our institution's emergency department (ED) with symptoms consistent with Clostridioides difficile infection. The patient was prescribed 2 weeks of oral vancomycin for CDI prior to presentation. Given insufficient response to vancomycin, the patient was started on fidaxomicin with a planned 10-day course. After 2 doses of fidaxomicin, the patient developed a rash on her back that spread within 24 hours. The patient did not experience relief upon administration of a variety of medications for allergic reaction. Improvement was noted upon discontinuation of fidaxomicin. The Food and Drug Administration reports that < 2% of adults treated with fidaxomicin experience a rash as an adverse effect. Conclusion: Fidaxomicin was a probable cause of morbilliform drug eruption in our patient with CDI. The patient improved upon discontinuation of fidaxomicin.

Azithromycin-Induced Generalized Nonbullous Fixed-Drug Eruption

Azithromycin-induced severe cutaneous reactions occur rare. We report a case of azithromycin-induced generalized nonbullous form of fixed-drug eruption (FDE). A 19-year-old male consulted the dermatology department for multiple painful oval-shaped, sharply defined, and hyperpigmented patches on his chest, abdomen, and upper limbs after consuming oral azithromycin tablets for his sore throat. The generalized nonbullous form of FDE was diagnosed, and the offending drug was stopped immediately. He was treated with antihistamines and steroids, and recovered on follow-up. This FDE is reported due to the spareseness of documentation from South India and to improve the awareness among the prescribing physicians about this severe cutaneous reaction (FDE) for a commonly used drug. This case report gives insight to the clinicians and health-care workers on rare side effects caused by the commonly used antimicrobial agent, azithromycin.

Delirium associated with the use of macrolide antibiotics: a review

OBJECTIVE

This review aimed to explore and summarise available cases of delirium suspected to be associated with the use of macrolide antibiotics reported in the literature and the United States Food and Drug Administration's Adverse Event Reporting System (FAERS) database.

METHODS

Electronic searches of the literature were conducted in four online databases: PubMed/MEDLINE, Scopus, Web of Science and Serbian Citation Index (SCIndeks). A search of FAERS database was also conducted to supplement the findings of the literature search. Descriptive statistics, narrative summation and tabulation of the extracted data were made.

RESULTS

Cases of delirium which satisfied inclusion criteria were found for clarithromycin, azithromycin, erythromycin and telithromycin. Delirium was described in patients of various age groups, including children. Drug-drug interactions may have contributed to its occurrence in some of the cases. Average time to onset of delirium was 2.5 days for azithromycin and 3.3 days for clarithromycin.

CONCLUSIONS

Considering that these drugs may be a possible cause of delirium, clinicians should be aware that timely recognition of this possible side effect can lead to earlier discontinuation of the culprit drug, reduce time spent in a delirious state and improve patients' outcomes.KEY POINTSCases of delirium which satisfied inclusion criteria were found for clarithromycin, azithromycin, erythromycin and telithromycin.Cases of delirium were described in patients of various age groups, including children.Drug-drug interactions may have contributed to the occurrence of delirium in some of the cases.Time to onset of delirium ranged from 2 to 3.5 days (mean: 2.5 days) for azithromycin and from 1 to 7 days (mean: 3.3 days) for clarithromycin.Cessation of the macrolide antibiotic seems to be the best management strategy, although some of the patients may, in addition, require antipsychotics.

Clarithromycin hypersensitivity in children: Is there a link with β-lactam hypersensitivity?

BACKGROUND

Clarithromycin hypersensitivity is reported as the most common cause of non-β-lactam antibiotic allergy in children. Clarithromycin is frequently prescribed in cases of suspected β-lactam hypersensitivity. Oral provocation tests stand as the gold standard to confirm drug hypersensitivity as diagnostic value of skin tests is variable. We analyzed the frequency of true clarithromycin hypersensitivity ratio and its relationship with β-lactam allergy among children with suspected clarithromycin hypersensitivity and evaluated the diagnostic value of skin tests.

METHODS

The study included 160 children referred with suspected clarithromycin hypersensitivity. Clinical history and allergy workups including skin tests or/and oral provocation tests were retrieved from medical records.

RESULTS

Oral provocation test confirmed clarithromycin hypersensitivity rate was 5.6% (n = 9/160). Skin tests with clarithromycin showed positivity in 32.6% (n = 29/89) of the tested patients. The sensitivity of clarithromycin skin tests was negligible, and specificity was 73.9% (95% confidence interval [CI], 64.7-81.8). Eighty-eight of the patients (55%) reported that they had previously tolerated a β-lactam antibiotic. β-lactam hypersensitivity was suspected in 40% (n = 64/160) of the patients (simultaneous [n = 10], sequential [n = 19], distant form [n = 35]) in relation with clarithromycin usage. β-lactam hypersensitivity (95% CI, 2.1-70.6, p = .005) and sequential usage of clarithromycin after the development of a rash with amoxicillin-clavulanic acid (95% CI, 2.0-96.4, p = .007) were found as risk factors for confirmed clarithromycin hypersensitivity.

CONCLUSION

The frequency of confirmed clarithromycin hypersensitivity was found low among suspected patients. Oral provocation test is crucial for definite diagnosis. Confirmed β-lactam allergy may be attributed as a risk factor for clarithromycin hypersensitivity, particularly clarithromycin treatment after a developing rash with amoxicillin-clavulanic acid in sequential usage.

Treatment of Community-Acquired Pneumonia: A Focus on Lefamulin

OBJECTIVE

The goal of this article is to review the clinical pharmacology, pharmacokinetics, efficacy, and safety of lemafulin.

DATA SOURCES

We performed a systematic literature review using the search terms of lefamulin and BC-3781 in the PubMed and EMBASE databases. We also cross-referenced the pertinent articles and searched ClinicalTrials.gov to identify ongoing and nonpublished studies.

STUDY SELECTION AND DATA EXTRACTION

Published data from 2005 to 2019 evaluating the clinical pharmacology, efficacy, and safety studies of lefamulin were analyzed.

DATA SYNTHESIS

In phase 3 clinical trials, two multicenter, randomized double-blinded studies-Lefamulin Evaluation Against Pneumonia 1 and 2 (LEAP 1 and 2)-compared the efficacy and safety of lemafulin with moxifloxacin in patients diagnosed with community-acquired bacterial pneumonia (CABP). Lemafulin given in doses of 600 mg orally or 150 mg intravenously were reported to have comparable efficacy to those of moxifloxacin with or without linezolid in patients with CABP. After the trial, the lefamulin group had an early clinical response (ECR) of 87.3% and the moxifloxacin group had an ECR of 90.2%. The difference of - 2.9% in the ECR was non-significant (CI - 8.5, 2.8).

RELEVANCE TO PATIENTS AND CLINICAL PRACTICE

Lemafulin exhibits a unique binding property; therefore, it possess a potentially lower predisposition for the development of bacterial resistance and cross-resistance to other antimicrobial classes. Lefamulin is active against gram-positive including methicillin-resistant strains and atypical organisms which are often implicated in CABP. Lefamulin may be a safe alternative for adult patients with CABP who may not be candidates for respiratory fluoroquinolones. Lefamulin demonstrates both bactericidal and bacteriostatic activity against gram-positive, fastidious gram-negatives, atypical pathogens, and some gram-negative anaerobes. It is bactericidal in vitro against Streptococcus pneumoniae, Haemophilus influenzae, and Mycoplasma pneumoniae (including macrolide-resistant strains) at concentrations of 0.06, 0.5, and 0.008 µg/ml respectively, and bacteriostatic against Staphylococcus aureus and Streptococcus pyogenes. The agent also demonstrates both time- and concentration-dependent killing against the pathogens S. pneumoniae and S. aureus. In vitro susceptibility testing demonstrated an MIC50/90 of 0.06/0.12 µg/ml against S. pneumoniae and S. aureus. The SENTRY Antimicrobial Surveillance Program found that at a concentration ≤ 1 µg/ml, lefamulin inhibited 100% S. pneumoniae isolates, 99.8% of S. aureus isolates, and 99.6% of methicillin-resistant S. aureus isolates. It was not affected by resistance to various antibiotic classes such as beta-lactams, fluoroquinolones, or macrolides.

Case report: SARS-CoV-2-induced urticaria or just a concomitance?

The association between urticaria and different virus infections has been reported in many studies. Different virus infections have been reported to be comorbidities of spontaneous urticaria. In this paper, we report the case of a male patient with acute urticaria 7 days after he left the hospital where he was treated for coronavirus disease 2019 (COVID-19). This infection may act as a causative or a facilitating factor for the initiation of acute urticaria and additional cofactors such as stress may contribute for the urticaria phenotype to be expressed. Additional facts for severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) virus in future will clarify if urticarial rash is one of the COVID's multiple faces.

Stevens-Johnson syndrome and toxic epidermal necrolysis associated with the use of macrolide antibiotics: a review of published cases

Macrolides are one of the most commonly prescribed antibiotics. In several studies, their use was associated with the occurrence of Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). This review aimed to explore and summarize available cases of SJS/TEN suspected to be associated with the use of macrolide antibiotics reported in the literature. Electronic searches were conducted in PubMed/MEDLINE, Web of Science, Scopus, and Serbian Citation Index (SCIndeks). Twenty-five publications describing a total of 27 patients were included. Cases of SJS/TEN which satisfied inclusion criteria were found for azithromycin (n = 11), clarithromycin (n = 7), erythromycin (n = 5), roxithromycin (n = 2), and telithromycin (n = 2). The age of the patients ranged from 2 to 77 years (median: 29 years). There were 14 female (51.9%) and 13 male (48.1%) patients. SJS was diagnosed in 16 patients (59.3%), TEN in 10 patients (37.0%), and SJS/TEN overlap in one patient (3.7%). Time to onset of the first symptoms ranged from 1 to 14 days (median: 3 days). All patients received some form of supportive and symptomatic care. Systemic corticosteroids were reported to be administered in 12 patients (44.4%) and intravenous immunoglobulin in five patients (18.5%). Three patients (11.1%) died. Considering that SJS/TEN is a severe and potentially life-threatening reaction, physicians should be aware that they could be adverse effects of macrolide antibiotics and keep in mind that prompt recognition of SJS/TEN and discontinuation of the culprit drug in combination with supportive care is essential.