Group determination of 14-membered macrolide antibiotics and azithromycin using antibodies against common epitopes.

Erythromycin (ERY), clarithromycin (CLA), roxithromycin (ROX), and azithromycin (AZI) are macrolide antibiotics widely used in livestock and human medicine. Therefore, they are frequently found as pollutants in environmental water. A method based on indirect competitive enzyme-linked immunosorbent assay (ELISA) for group determination of these macrolides in foodstuffs, human biofluids, and water was developed. Carboxymethyloxime of clarithromycin (CMO-CLA) was synthesized and conjugated to bovine serum albumin (BSA) and gelatin to prepare immunogen and coating antigen with advantageous presentation of target epitopes, l-cladinose and d-desosamine, common for these analytes. Antibodies generated in rabbits were capable of recognizing ERY, CLA, and ROX as a group (100-150%), and AZI (12%) and did not cross-react with ERY degradants, which lack antibiotic activity. Assay displayed sensitivity of determination of 14-membered macrolides (IC50=0.13-0.2ng/ml) and low limit of detection (LOD) that was achieved at 0.02 to 0.03ng/ml. It allowed performing analysis of milk, muscle, eggs, bovine serum, water, human serum and urine, and avoiding matrix effect without special pretreatment using simple dilution with assay buffer. For 15-membered macrolide AZI, the corresponding characteristics were IC50=1.6ng/ml and LOD=0.14ng/ml. The recoveries of veterinary and human medicine macrolides from corresponding matrices were validated and found to be satisfactory.

Azithromycin anaphylaxis in children.

Allergic reactions associated to the use of macrolides are uncommon; in particular only two cases of anaphylaxis with erithromycin and clarithromycin have been reported to date. The aim of this study was to investigate macrolide-induced anaphylaxis. Between December 2007 and December 2011, 136 consecutive children were referred to the Allergy Unit of A. Meyer Children's Hospital because of a past history of reactions to macrolides. Allergy work-ups were carried out according to the European Network for Drug Allergy protocol. Anaphylaxis was diagnosed according to the clinical criteria proposed by Sampson et al. and graded according to Brown SGA et al. Sixty-six out of 136 patients completed the allergologic work-up and among them we investigated three cases of anaphylaxis due to azithromycin which included one child with anaphylaxis to both clarithromycin and azithromycin. In two of the children with anaphylaxis, the diagnosis was only confirmed with the skin prick test, the third was positive to the Intradermal Test. The azithromycin allergy shows a surprisingly high sensitivity to the in-vivo tests. Moreover, this study shows that cross-reactivity may occur between different macrolidic molecules; it has even been suggested that macrolide allergies are unlikely to be class allergies.

Anti-inflammatory mechanism of action of azithromycin in LPS-stimulated J774A.1 cells.

Azithromycin is a macrolide antibiotic with well-described anti-inflammatory properties which can be attributed, at least partially, to its action on macrophages. We have previously shown, with 18 different macrolide molecules, that IL-6 and PGE2 inhibition correlates with macrolide accumulation, as well as with their binding to phospholipids in J774A.1 cells. The present study was performed in order to substantiate the hypothesis that biological membranes are a target for macrolide anti-inflammatory activity. By analyzing the effect of azithromycin on overall eicosanoid production, we found that in LPS-stimulated J774A.1 cells, azithromycin, like indomethacin, inhibited the synthesis of all eicosanoids produced downstream of COX. Upstream of COX, azithromycin inhibited arachidonic acid release in the same way as a cPLA2 inhibitor, while indomethacin had no effect. Further comparison revealed that in LPS-stimulated J774A.1 cells, the cPLA2 inhibitor showed the same profile of inhibition as azithromycin in inhibiting PGE2, IL-6, IL-12p40 and arachidonic acid release. Therefore, we propose that the anti-inflammatory activity of azithromycin in this model may be due to interactions with cPLA2, causing inadequate translocation of the enzyme or disturbing physical interactions with its substrates.

The prevalence of antibiotic skin test reactivity in a pediatric population.

Although adverse drug reactions (ADRs) are not uncommon, true allergic (i.e., immunologic) reactions are infrequent. Estimates are that only 10% of reported "penicillin (PCN)-allergic" patients have true allergic drug reactions. Most studies of PCN-related ADR have been conducted in adult populations and suggest that the majority of adult patients presenting with PCN allergy history can safely receive the drug. The goal of this study was to examine the outcome of provocative drug challenges to antibiotics in a pediatric population and correlate outcomes with predictive factors. Through chart review, we identified 96 pediatric patients with history of an ADR to antibiotics who underwent skin testing (ST) and/or graded challenges to PCN (n = 52), cephalosporins (n = 7), azithromycin (AZT; n = 24), or clindamycin (n = 4). Of these children with an ADR, 87 (90.6%) tolerated provocative drug challenges and 9 (9.4%) were instructed to continue drug avoidance because of positive ST or failed challenge. Eight of the nine patients continued drug avoidance due to positive PCN ST (n = 4) or ADR during drug PCN challenge (n = 4). All AZT and cephalosporin challenges had negative outcomes, and only one patient did not proceed with the clindamycin challenge after a positive ST. True "antibiotic allergy" denoted by positive ST or failed challenge in patients with a history of ADR occurred in <10% of children included in this study, suggesting that without such testing nearly 90% might be treated with alternative antibiotics unnecessarily.

Macrolide antibiotics aggravate experimental autoimmune encephalomyelitis and inhibit inducible nitric oxide synthase.

Recent studies have implicated Chlamydia pneumoniae (C. pneumoniae) is present in a subset of patients with multiple sclerosis (MS) in which C. pneumoniae could act as a cofactor in the development of the disease. Macrolide antibiotics are most widely used anti-chlamydial agents and have immunomodulatory effect independently of their anti-bacterial activity. To investigate their effects on experimental autoimmune encephalomyelitis (EAE), EAE was induced by immunization with MBP68-86 peptide emulsified in complete Freund's adjuvant (CFA). Clarithromycin (CM) or azithromycin (AM, 50 mg/100 g body weight) was administrated daily from day 2 before immunization. All rats developed and survived EAE, but the groups administrated CM or AM had more severe symptoms. On day 11 post-immunization, mononuclear cells (MNCs) were prepared from the spleen of control group and cultured with or without macrolide antibiotics (10mug/ml). We evaluated nitric oxide (NO) production in the serum and culture supernatant. Inducible nitric oxide synthase (iNOS) mRNA and protein expression in the spinal cords and cultured MNCs were measured. The results showed that CM and AM similarly inhibited NO production and iNOS mRNA and protein expression in vivo and in vitro. Macrolide antibiotics may aggravate EAE by inhibiting iNOS mRNA and protein expression. Further studies are needed to investigate the effect of macrolide antibiotics on MS and to compare the effect of different anti-chlamydial antibiotics on MS.

Carmine hypersensitivity masquerading as azithromycin hypersensitivity.

Macrolide hypersensitivity is a rarely reported event. However, carmine dye has become increasingly important as a provocative agent. We present a case of a woman with documented carmine hypersensitivity, who reported anaphylaxis 90 minutes after ingestion of a generic azithromycin. Our investigations revealed that this was an allergy to the carmine dye in the tablet's coating rather than to the antibiotic. Seven extracts were prepared including carmine dye, crushed dried female cochineal insects, crushed tablets of Zithromax (Pfizer Inc.) and generic azithromycin (Teva Pharmaceuticals), and the crushed colored coatings from both tablets. These were suspended in preservative-free normal saline, and then applied as a skin-prick test and read at 30 minutes. The skin-prick skin test results were 4+ to histamine and carmine dye, but negative to cochineal insect extract, Pfizer crushed tablets, and negative control. The patient was 1+ to the Teva crushed tablet, but was 4+ to the Teva brand coating and negative to the Pfizer brand coating, which did not contain carmine. The patient subsequently ingested Pfizer Zithromax without any sequelae. To our knowledge, this is the first reported case of carmine anaphylaxis attributed to carmine-containing medication. Careful history and skin-prick testing to the appropriate agents allowed elucidation of the subtlety of the true offending agent without unnecessary avoidance of the medication class. Patients with a carmine hypersensitivity should actively check with their pharmacy or prescribing physician to verify their medications are free of this offending agent.

Resistência da Neisseria gonorrhoeae a antimincrobianos em Manaus: período 2005-2006 / Neisseria gonorrhoeae antimicrobial resistance in Manaus: 2005-2006 period

Introdução: em 1998, a Fundação Alfredo da Matta, de Manaus, iniciou estudos para avaliar a resistência de isolados de N. gonorrhoeae aos antibióticos recomendados para o tratamento das uretrites e cervicites gonocócicas. Objetivo: verificar a resistência de isolados de Neisseria gonorrhoeae aos antibióticos penicilina, tetraciclina, azitromicina, ceftriaxona e ciprofloxacino no Laboratório de Bacteriologia Clínica da Fundação Alfredo da Matta, Manaus - Amazonas - Brasil. Métodos: neste estudo, avaliou-se a resistência de 110 gonococos à penicilina, à tetraciclina, à azitromicina, à ceftriaxona e ao ciprofloxacino pelo método de difusão com discos. Resultados: após os testes, verificou-se que 14,5% foram betalactamase positivos (PPNG) e a resistência à penicilina foi de 21,8%. Para a tetraciclina, 80,0% foram resistentes com 12,7% TRNG. Em relação à azitromicina, 8,2% dos isolados foram resistentes e não se detectou resistência ao ciprofloxacino e à ceftriaxona, porém 6,4% apresentaram sensibilidade reduzida ao primeiro e 5,5% diâmetro inferior a 33mm ao segundo. Conclusão: ao final, conclui-se que os altos percentuais de resistência à penicilina e tetraciclina são semelhantes aos observados em outros estudos realizados com cepas da região e sugerem que ainda há elevada pressão seletiva desses antibióticos sobre os gonococos. Os índices de resistência à azitromicina inviabilizam sua utilização como opção terapêutica. Tanto o ciprofloxacino quanto a ceftriaxona foram eficazes "in vitro", mas as taxas de sensibilidade reduzida de ciprofloxacino e os valores abaixo de 35 mm de diâmetro no antibiograma para a ceftriaxona, são indicativos da necessidade do monitoramento clínico e laboratorial constante desses medicamentos.

Técnicas de estudio de fagocitosis in vivo y su aplicación en la investigación de la actividad inmunomuduladora de antibióticos / Procedures to study the in vivo phagocytosis and application for the investigation of immunomodulatory activity of antibiotics

La depuración de partículas de la sangre es una medida de la capacidad funcional del sistema fagocítico mononuclear, responsable de la eliminación sistémica de microorganismo patógenos, inmunocomplejos y células apoptósicas. Esta capacidad puede ser alterada por agentes modificadores de la respuesta biológica, entre los que figuran numerosos agentes antimicrobianos. En este trabajo se comparó la efectividad de la medida de la capacidad de depuración de ratones BALB/c inoculados con distintos microorganismos (una levadura, dos bacterias Gram-positivas, extra- e intracelular, y dos bacterias Gram-negativas, asimismo extra- e intracelular). La levadura Candida albicans fue seleccionada, por su apropiada cinética de depuración y su resistencia natural a agentes antibacterianos, para estudiar la modificación de la fagocitosis in vivo por el antibiótico macrólido azitromicina. El tratamiento con azitromicina durante 10 y 20 días disminuyó la capacidad de depuración del sistema fagocítico-mononuclear

The blood stream clearance of particles is a measure of the functional capacity of the mononuclear phagocytic system, which is responsible for the systemic elimination of pathogenic microorganisms, immunocomplexes and apoptotic cells. This capacity may be altered by biological reponse modifiersresponse, in which numerous antimicrobial agents are present. In this work, the effectiveness of the measurement of clearance capacity was compared in BALB/c mice that were inoculated with different microorganisms (a yeast, two extra and intracellular gram-positive bacteria, and two extra and intracellular gram-negative bacteria). As a means to studying the in vivo modification of phagocytosis by the macrolid antibiotic, azithromycin, the yeast C Candida andida albicans was chosen for its appropriate clearance kinetics and its natural resistance to antibacterial agents. Treatment with azithromycin for 10 and 20 days reduced clearance capacity of the mononuclear phagocytic system

Maintenance azithromycin therapy for bronchiolitis obliterans syndrome: results of a pilot study.

Bronchiolitis obliterans syndrome remains the leading cause of morbidity and mortality in the pulmonary transplant population. Previous studies show that macrolide antibiotics may be efficacious in the treatment of panbronchiolitis and cystic fibrosis. In the latter, azithromycin decreases the number of respiratory exacerbations, improves FEV1, and improves quality of life. We hypothesized that oral azithromycin therapy may improve lung function in patients with bronchiolitis obliterans syndrome. To test this hypothesis, we conducted an open-label pilot trial using maintenance azithromycin therapy in six lung transplant recipients (250 mg orally three times per week for a mean of 13.7 weeks). In this study, five of these six individuals demonstrated significant improvement in pulmonary function, as assessed by FEV1, as compared with their baseline values at the start of azithromycin therapy. The mean increase in the percentage of predicted FEV1 values in these individuals was 17.1% (p

[Safety of azithromycin in patients allergic to penicillin and cephalosporin]. / Sicurezza dell'azitromicina in pazienti allergici a penicillina e cefalosporina.

We have evaluated the safety of a new antibiotic, azithromicin, in 48 patients with allergy to penicillin and/or to cephalosporin. Diagnosis of allergy was based on clinical history, skin test and detection of serum specific IgE. The most common symptoms were urticaria, oedema, pruritus, oral aphthosis. Azithromicin was administered at the increasing dosage of 100-200-300 and 400 mg every 2 days. Our patients did not show any reaction to azithromicin. This antibiotic is therefore a valid alternative to penicillin and/or cephalosporin in patients allergic to these two drugs.