The macrolides: erythromycin, clarithromycin, and azithromycin

The role of the methoxy group in approved drugs

The methoxy substituent is prevalent in natural products and, consequently, is present in many natural product-derived drugs. It has also been installed in modern drug molecules with no remnant of natural product features because medicinal chemists have been taking advantage of the benefits that this small functional group can bestow on ligand-target binding, physicochemical properties, and ADME parameters. Herein, over 230 methoxy-containing small-molecule drugs, as well as several fluoromethoxy-containing drugs, are presented from the vantage point of the methoxy group. Biochemical mechanisms of action, medicinal chemistry SAR studies, and numerous X-ray cocrystal structures are analyzed to identify the precise role of the methoxy group for many of the drugs and drug classes. Although the methoxy substituent can be considered as the hybridization of a hydroxy and a methyl group, the combination of these functionalities often results in unique effects that can amount to more than the sum of the individual parts.

Acceleration of infectious disease drug discovery and development using a humanized model of drug metabolism

A key step in drug discovery, common to many disease areas, is preclinical demonstration of efficacy in a mouse model of disease. However, this demonstration and its translation to the clinic can be impeded by mouse-specific pathways of drug metabolism. Here, we show that a mouse line extensively humanized for the cytochrome P450 gene superfamily ("8HUM") can circumvent these problems. The pharmacokinetics, metabolite profiles, and magnitude of drug-drug interactions of a test set of approved medicines were in much closer alignment with clinical observations than in wild-type mice. Infection with Mycobacterium tuberculosis, Leishmania donovani, and Trypanosoma cruzi was well tolerated in 8HUM, permitting efficacy assessment. During such assessments, mouse-specific metabolic liabilities were bypassed while the impact of clinically relevant active metabolites and DDI on efficacy were well captured. Removal of species differences in metabolism by replacement of wild-type mice with 8HUM therefore reduces compound attrition while improving clinical translation, accelerating drug discovery.

Increased risk of hearing loss associated with macrolide use: a systematic review and meta-analysis

The increased risk of hearing loss with macrolides remains controversial. We aimed to systematically review and meta-analyze data on the clinical risk of hearing loss, tinnitus, and ototoxicity following macrolide use. A systematic search was conducted across PubMed, MEDLINE, Cochrane, and Embase databases from database inception to May 2023. Medical Subject Heading (MeSH) terms and text keywords were utilized, without any language restrictions. In addition to the electronic databases, two authors manually and independently searched for relevant studies in the US and European clinical trial registries and Google Scholar. Studies that involved (1) patients who had hearing loss, tinnitus, or ototoxicity after macrolide use, (2) intervention of use of macrolides such as azithromycin, clarithromycin, erythromycin, fidaxomicin, roxithromycin, spiramycin, and/or telithromycin, (3) comparisons with specified placebos or other antibiotics, (4) outcomes measured as odds ratio (OR), relative risk (RR), hazard ratio (HR), and mean difference for ototoxicity symptoms using randomized control trial (RCT)s and observational studies (case-control, cross-section, and cohort studies) were included. Data extraction was performed independently by two extractors, and a crosscheck was performed to identify any errors. ORs along with their corresponding 95% confidence intervals (CIs) were estimated using random-effects models. The Preferred Reporting Items for Systematic Reviews and Meta-analyses reporting guidelines for RCTs and Meta-Analysis of Observational Studies in Epidemiology guidelines for observational studies were followed. We assessed the hearing loss risk after macrolide use versus controls (placebos and other antibiotics). Based on data from 13 studies including 1,142,021 patients (n = 267,546 for macrolide and n = 875,089 for controls), the overall pooled OR was 1.25 (95% CI 1.07-1.47). In subgroup analysis by study design, the ORs were 1.37 (95% CI 1.08-1.73) for RCTs and 1.33 (95% CI 1.24-1.43) for case-control studies, indicating that RCT and case-control study designs showed a statistically significant higher risk of hearing loss. The group with underlying diseases such as multiple infectious etiologies (OR, 1.16 [95% CI 0.96-1.41]) had a statistically significant lower risk than the group without (OR, 1.53 [95% CI 1.38-1.70] P = .013). The findings from this systematic review and meta-analysis suggest that macrolide antibiotics increase the risk of hearing loss and that healthcare professionals should carefully consider this factor while prescribing macrolides.

Clinical profile and outcomes of Scrub typhus in pregnant women presenting to a tertiary care hospital of North India

Scrub typhus, caused by Orientia tsutsugamushi, is a re-emerging endemic zoonosis in the Asia Pacific region. It is a febrile condition ranging in severity from mild to severe, with fatality rates as high as 30%. The present study aims towards analysing the clinical profile and pregnancy outcomes in 27 cases of scrub typhus admitted to a tertiary care centre in North India. The medical records of 27 pregnant women who had scrub typhus were analysed. The IgM ELISA was used to look for IgM antibodies to Orientia tsutsugamushi in the patient's serum sample. An optical density of more than or equal to 0.468 was considered as positive. Majority of the pregnant females delivered healthy and live babies. However, poor foetal outcomes were observed in four (14.8%) cases with intrauterine deaths occurring in two (7.4%) cases and still birth in one (3.7%) case, while one (3.7%) patient had spontaneous abortion. Maternal mortality was reported in one patient (3.7%) due to a delay in diagnosis. In endemic settings, a strong index of suspicion for scrub typhus is necessary in pregnant females presenting with fever. The key to reducing morbidity in both the mother and foetus is early diagnosis and treatment.Impact StatementWhat is already known on this subject? Scrub typhus is a febrile condition ranging in severity from mild to severe, with 30% mortality in untreated patients.What do the results of this study add? Majority of the pregnant females delivered healthy and live babies. However, poor foetal outcomes were observed in four (14.8%) cases with intrauterine deaths occurring in two (7.4%) cases and still birth in one (3.7%) case, while one (3.7%) patient had spontaneous abortion. Maternal mortality was reported in one patient (3.7%) due to a delay in diagnosis.What are the implications of these findings for clinical practice and/or further research? In endemic settings, a strong index of suspicion for scrub typhus is necessary for pregnant females presenting with fever. The key to reducing morbidity in both the mother and foetus is early diagnosis and treatment.

Novel Approaches to Characterize Individual Drug Metabolism and Advance Precision Medicine

Interindividual variability in drug metabolism can significantly affect drug concentrations in the body and subsequent drug response. Understanding an individual's drug metabolism capacity is important for predicting drug exposure and developing precision medicine strategies. The goal of precision medicine is to individualize drug treatment for patients to maximize efficacy and minimize drug toxicity. While advances in pharmacogenomics have improved our understanding of how genetic variations in drug-metabolizing enzymes (DMEs) affect drug response, nongenetic factors are also known to influence drug metabolism phenotypes. This minireview discusses approaches beyond pharmacogenetic testing to phenotype DMEs-particularly the cytochrome P450 enzymes-in clinical settings. Several phenotyping approaches have been proposed: traditional approaches include phenotyping with exogenous probe substrates and the use of endogenous biomarkers; newer approaches include evaluating circulating noncoding RNAs and liquid biopsy-derived markers relevant to DME expression and function. The goals of this minireview are to 1) provide a high-level overview of traditional and novel approaches to phenotype individual drug metabolism capacity, 2) describe how these approaches are being applied or can be applied to pharmacokinetic studies, and 3) discuss perspectives on future opportunities to advance precision medicine in diverse populations. SIGNIFICANCE STATEMENT: This minireview provides an overview of recent advances in approaches to characterize individual drug metabolism phenotypes in clinical settings. It highlights the integration of existing pharmacokinetic biomarkers with novel approaches; also discussed are current challenges and existing knowledge gaps. The article concludes with perspectives on the future deployment of a liquid biopsy-informed physiologically based pharmacokinetic strategy for patient characterization and precision dosing.

Capture-SELEX: Selection Strategy, Aptamer Identification, and Biosensing Application

Small-molecule contaminants, such as antibiotics, pesticides, and plasticizers, have emerged as one of the substances most detrimental to human health and the environment. Therefore, it is crucial to develop low-cost, user-friendly, and portable biosensors capable of rapidly detecting these contaminants. Antibodies have traditionally been used as biorecognition elements. However, aptamers have recently been applied as biorecognition elements in aptamer-based biosensors, also known as aptasensors. The systematic evolution of ligands by exponential enrichment (SELEX) is an in vitro technique used to generate aptamers that bind their targets with high affinity and specificity. Over the past decade, a modified SELEX method known as Capture-SELEX has been widely used to generate DNA or RNA aptamers that bind small molecules. In this review, we summarize the recent strategies used for Capture-SELEX, describe the methods commonly used for detecting and characterizing small-molecule-aptamer interactions, and discuss the development of aptamer-based biosensors for various applications. We also discuss the challenges of the Capture-SELEX platform and biosensor development and the possibilities for their future application.

Erythromycin Formulations—A Journey to Advanced Drug Delivery

Erythromycin (ERY) is a macrolide compound with a broad antimicrobial spectrum which is currently being used to treat a large number of bacterial infections affecting the skin, respiratory tract, intestines, bones and other systems, proving great value from a clinical point of view. It became popular immediately after its discovery in 1952, due to its therapeutic effect against pathogens resistant to other drugs. Despite this major advantage, ERY exhibits several drawbacks, raising serious clinical challenges. Among them, the very low solubility in water and instability under acidic conditions cause a limited efficacy and bioavailability. Apart from this, higher doses promote drug resistance and undesirable effects. In order to overcome these disadvantages, during the past decades, a large variety of ERY formulations, including nanoparticles, have emerged. Despite the interest in ERY-(nano)formulations, a review on them is lacking. Therefore, this work was aimed at reviewing all efforts made to encapsulate ERY in formulations of various chemical compositions, sizes and morphologies. In addition, their preparation/synthesis, physico-chemical properties and performances were carefully analysed. Limitations of these studies, particularly the quantification of ERY, are discussed as well.

Important Roles and Potential Uses of Natural and Synthetic Antimicrobial Peptides (AMPs) in Oral Diseases: Cavity, Periodontal Disease, and Thrush

Numerous epithelial cells and sometimes leukocytes release AMPs as their first line of defense. AMPs encompass cationic histatins, defensins, and cathelicidin to encounter oral pathogens with minimal resistance. However, their concentrations are significantly below the effective levels and AMPs are unstable under physiological conditions due to proteolysis, acid hydrolysis, and salt effects. In parallel to a search for more effective AMPs from natural sources, considerable efforts have focused on synthetic stable and low-cytotoxicy AMPs with significant activities against microorganisms. Using natural AMP templates, various attempts have been used to synthesize sAMPs with different charges, hydrophobicity, chain length, amino acid sequence, and amphipathicity. Thus far, sAMPs have been designed to target Streptococcus mutans and other common oral pathogens. Apart from sAMPs with antifungal activities against Candida albicans, future endeavors should focus on sAMPs with capabilities to promote remineralization and antibacterial adhesion. Delivery systems using nanomaterials and biomolecules are promising to stabilize, reduce cytotoxicity, and improve the antimicrobial activities of AMPs against oral pathogens. Nanostructured AMPs will soon become a viable alternative to antibiotics due to their antimicrobial mechanisms, broad-spectrum antimicrobial activity, low drug residue, and ease of synthesis and modification.

A Reference-Scaled Average Bioequivalence Study of Azithromycin Tablets Manufactured in China and the United States: An Open-Label, Randomized, Single-Dose, 3-Way Crossover Study in Healthy Chinese Subjects Under Fasted and Fed Conditions

Azithromycin (Zithromax) is an azalide antibiotic that binds to the 50S ribosomal subunit of the susceptible organism and thereby interferes with its protein synthesis. An open-label, randomized, single-dose, 3-way crossover bioequivalence study was conducted to compare the rate and extent of absorption of the azithromycin 250-mg tablet manufactured at Pfizer Dalian (China) and that at Pfizer Barceloneta (United States) under fasted and fed conditions in healthy Chinese subjects. This study aimed to support a generic consistency evaluation program, initiated by the National Medical Products Administration, for evaluating the quality and efficacy of the products manufactured in China. In the study, the within-subject standard deviation for area under the serum concentration-time profile from time 0 to 72 hours after dosing in the fasted condition was <0.294, and the 90%CI for the ratio was within 80% to 125%; the within-subject SDs for serum peak concentration in the fasted condition, area under the serum concentration-time profile from time 0 to 72 hours after dosing in the fed condition, and serum peak concentration in the fed condition, were all >0.294, with the upper confidence bounds being <0.00, and the point estimates of the ratios being within 80% to 125%. The results support the bioequivalence between azithromycin tablets manufactured in China and the United States in fasted and fed conditions, with both tablets showing an acceptable safety/tolerability profile in the studied population.

The Current Status and Prevention of Antibiotic Pollution in Groundwater in China

The problem of environmental pollution caused by the abuse of antibiotics has received increasing attention. However, only in recent years have antibiotic pollution and its risk assessment to the environment been deeply studied. Although there has been a large number of reports about the input, occurrence, destination, and influence of antibiotics in the past 10 years, systemic knowledge of antibiotics in the groundwater environment is still lacking. This review systematically expounds the sources, migration and transformation, pollution status, and potential risks to the ecological environment of antibiotics in groundwater systems, by integrating 10 years of existing research results. The results showed that 47 kinds of antibiotics in four categories, mainly sulfonamides and fluoroquinolones, have been detected; antibiotics in groundwater species will induce the production of resistance genes and cause ecological harm. In view of the entire process of antibiotics entering groundwater, the current antibiotic control methods at various levels are listed, including the control of the discharge of antibiotics at source, the removal of antibiotics in water treatment plants, and the treatment of existing antibiotic contamination in groundwater. Additionally, the future research direction of antibiotics in groundwater is pointed out, and suggestions and prospects for antibiotic control are put forward.

Ribosome-Directed Therapies in Cancer

The human ribosomes are the cellular machines that participate in protein synthesis, which is deeply affected during cancer transformation by different oncoproteins and is shown to provide cancer cell proliferation and therefore biomass. Cancer diseases are associated with an increase in ribosome biogenesis and mutation of ribosomal proteins. The ribosome represents an attractive anti-cancer therapy target and several strategies are used to identify specific drugs. Here we review the role of different drugs that may decrease ribosome biogenesis and cancer cell proliferation.

Compounds for selective translational inhibition

Since many human diseases are caused by the unwelcome production of harmful proteins, compounds that selectively suppress protein synthesis should provide a unique path for drug development, expanding the druggable proteome. Although surveying the RNA/amino acid contexts that are preferentially affected by translation inhibitors has presented an analytic hurdle, the application of a technique termed ribosome profiling overcomes this problem. Indeed, this technique uncovers the selectivity of translation repression by small molecules such as chloramphenicol, macrolides, PF846, and rocaglates. The molecular understanding of how the compounds inspire context selectivity, despite their targeting to general translation machinery, facilitates rational drug design and discovery for therapeutic purposes.

Microbiological Aspects of Unique, Rare, and Unusual Fatty Acids Derived from Natural Amides and Their Pharmacological Profile

In the proposed review, the pharmacological profile of unique, rare, and unusual fatty acids derived from natural amides is considered. These amides are produced by various microorganisms, lichens, and fungi. The biological activity of some natural fatty acid amides has been determined by their isolation from natural sources, but the biological activity of fatty acids has not been practically studied. According to QSAR data, the biological activity of fatty acids is shown, which demonstrated strong antifungal, antibacterial, antiviral, antineoplastic, anti-inflammatory activities. Moreover, some fatty acids have shown rare activities such as antidiabetic, anti-infective, anti-eczematic, antimutagenic, and anti-psoriatic activities. For some fatty acids that have pronounced biological properties, 3D graphs are shown that show a graphical representation of unique activities. These data are undoubtedly of both theoretical and practical interest for chemists, pharmacologists, as well as for the pharmaceutical industry, which is engaged in the synthesis of biologically active drugs.

Nano-Architectonics of Antibiotic-Loaded Polymer Particles as Vehicles for Active Molecules

Recently, nanotechnology research studies have been proven that use of various nanoparticles as drug delivery systems to target and to annihilate pathogenic microorganisms may be a good solution for prevention and treatment of severe infection. In the last few years, antimicrobial drug encapsulation into nano-sized systems has materialized as a promising alternative that increased drug efficacy and minimized adverse effects. Physicochemical properties of erythromycin-loaded polymer nanoparticles were assessed using particle size distribution, HPLC, FTIR, TG/DTA, and SEM characterization techniques. The as-prepared samples exhibited an average particle size of 340 and 270 nm, respectively, with erythromycin content of 99.7% in both samples. From the release profile of erythromycin from PLA/PLGA, a prolonged drug release can be observed from both Ery-PLA and Ery-PLGA nanostructures. Morphology images exhibited spherical, rigid, and ring-shaped nanoparticles. Thermal analytical study in the case of Ery-PLA and Ery-PLGA samples showed that pure drug has an endothermic peak at around 150 °C assigned to a melting point. The antibiotic melting peak disappeared for both antibiotic-loaded PLA and PLGA nanoparticles thermographs, denoting the presence of erythromycin. This indicates that the antibiotic is uniformly dispensed throughout the host polymer matrix at nanometer scale. FTIR spectra of Ery-PLA and Ery-PLGA nano-architectures with almost similar peaks indicated no alteration in chemical structure of drug-loaded polymer nanoparticles.

Macrolides versus placebo for chronic asthma

BACKGROUND

Asthma is a chronic disease in which inflammation of the airways causes symptomatic wheezing, coughing and difficult breathing. Macrolides are antibiotics with antimicrobial and anti-inflammatory activities that have been explored for the long-term control of asthma symptoms.

OBJECTIVES

To assess the effects of macrolides compared with placebo for managing chronic asthma.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register up to March 2021. We also manually searched bibliographies of previously published reviews and conference proceedings and contacted study authors. We included records published in any language in the search.

SELECTION CRITERIA

We included randomised controlled clinical trials (RCTs) involving both children and adults with asthma treated with macrolides versus placebo for four or more weeks. Primary outcomes were exacerbation requiring hospitalisation, severe exacerbations (exacerbations requiring emergency department (ED) visits or systemic steroids, or both), symptom scales, asthma control questionnaire (ACQ, score from 0 totally controlled, to 6 severely uncontrolled), Asthma Quality of Life Questionnaire (AQLQ, with score from 1 to 7 with higher scores indicating better QoL), rescue medication puffs per day, morning and evening peak expiratory flow (PEF; litres per minutes), forced expiratory volume in one second (FEV1; litres), bronchial hyperresponsiveness, and oral corticosteroid dose. Secondary outcomes were adverse events (including mortality), withdrawal, blood eosinophils, sputum eosinophils, eosinophil cationic protein (ECP) in serum, and ECP in sputum.

DATA COLLECTION AND ANALYSIS

Two review authors independently examined all records identified in the searches then reviewed the full text of all potentially relevant articles before extracting data in duplicate from all included studies. As per protocol, we used a fixed-effect model. We conducted a sensitivity analysis for analyses with high heterogeneity (I2 greater than 30%). GRADE was used to assess the certainty of the body of evidence.

MAIN RESULTS

Twenty-five studies met the inclusion criteria, randomising 1973 participants to receive macrolide or placebo for at least four weeks. Most of the included studies reported data from adults (mean age 21 to 61 years) with persistent or severe asthma, while four studies included children. All participants were recruited in outpatient settings. Inclusion criteria, interventions and outcomes were highly variable. The evidence suggests macrolides probably deliver a moderately sized reduction in exacerbations requiring hospitalisations compared to placebo (odds ratio (OR) 0.47, 95% confidence interval (CI) 0.20 to 1.12; studies = 2, participants = 529; moderate-certainty evidence). Macrolides probably reduce exacerbations requiring ED visits and/or treatment with systemic steroids (rate ratio (RaR) 0.65, 95% CI 0.53 to 0.80; studies = 4, participants = 640; moderate-certainty evidence). Macrolides may reduce symptoms (as measured on symptom scales) (standardised mean difference (SMD) -0.46, 95% CI -0.81 to -0.11; studies = 4, participants = 136 ; very low-certainty evidence). Macrolides may result in a little improvement in ACQ (SMD -0.17, 95% CI -0.31 to -0.03; studies = 5, participants = 773; low-certainty evidence). Macrolides may have little to no effect on AQLQ (mean difference (MD) 0.24, 95% CI 0.12 to 0.35; studies = 6, participants = 802; very low-certainty evidence). For both the ACQ and the AQLQ the suggested effect of macrolides versus placebo did not reach a minimal clinically important difference (MCID, 0.5 for ACQ and AQLQ) (ACQ: low-certainty evidence; AQLQ: very low-certainty evidence). Due to high heterogeneity (I2 > 30%), we conducted sensitivity analyses on the above results, which reduced the size of the suggested effects by reducing the weighting on the large, high quality studies.  Macrolides may result in a small effect compared to placebo in reducing need for rescue medication (MD -0.43 puffs/day, 95% CI -0.81 to -0.04; studies = 4, participants = 314; low-certainty evidence). Macrolides may increase FEV1, but the effect is almost certainly below a level discernible to patients (MD 0.04 L, 95% CI 0 to 0.08; studies = 10, participants = 1046; low-certainty evidence). It was not possible to pool outcomes for non-specific bronchial hyperresponsiveness or lowest tolerated oral corticosteroid dose (in people requiring oral corticosteroids at baseline). There was no evidence of a difference in severe adverse events (including mortality), although less than half of the studies reported the outcome (OR 0.80, 95% CI 0.49 to 1.31; studies = 8, participants = 854; low-certainty evidence). Reporting of specific adverse effects was too inconsistent across studies for a meaningful analysis.

AUTHORS' CONCLUSIONS

Existing evidence suggests an effect of macrolides compared with placebo on the rate of exacerbations requiring hospitalisation. Macrolides probably reduce severe exacerbations (requiring ED visit and/or treatment with systemic steroids) and may reduce symptoms. However, we cannot rule out the possibility of other benefits or harms because the evidence is of very low quality due to heterogeneity among patients and interventions, imprecision and reporting biases. The results were mostly driven by a well-designed, well powered RCT, indicating that azithromycin may reduce exacerbation rate and improve symptom scores in severe asthma. The review highlights the need for researchers to report outcomes accurately and according to standard definitions. Macrolides can reduce exacerbation rate in people with severe asthma. Future trials could evaluate if this effect is sustained across all the severe asthma phenotypes, the comparison with newer biological drugs, whether effects persist or wane after treatment cessation and whether effects are associated with infection biomarkers.

Development of Genetically Encoded Biosensors for Reporting the Methyltransferase-Dependent Biosynthesis of Semisynthetic Macrolide Antibiotics

Clarithromycin is an improved semisynthetic analogue of the naturally occurring macrolide, erythromycin. The subtle modification of a methyl group on the C-6 hydroxyl group endows the molecule with improved acid stability and results in a clinically useful antibiotic. Here, we show that the effector specificity of the biosensor protein, MphR, can be evolved to selectively recognize clarithromycin and therefore report on the production of this molecule in vivo. In addition, a crystal structure of the evolved variant reveals the molecular basis for selectivity and provides a guide for the evolution of a new metabolic function using this biosensor.

Cotton and Surgical Face Masks in Community Settings: Bacterial Contamination and Face Mask Hygiene

During the current COVID-19 pandemic, the use of face masks has become increasingly recommended and even mandatory in community settings. To evaluate the risk of bacterial cross-contamination, this study analyzed the bacterial bioburden of disposable surgical masks and homemade cotton masks, and surveyed the habits and face mask preferences of the Flemish population. Using culture approaches and 16S rRNA gene amplicon sequencing, we analyzed the microbial community on surgical and/or cotton face masks of 13 healthy volunteers after 4 h of wearing. Cotton and surgical masks contained on average 1.46 × 10⁵ CFU/mask and 1.32 × 10⁴ CFU/mask, respectively. Bacillus, Staphylococcus, and Acinetobacter spp. were mostly cultured from the masks and 43% of these isolates were resistant to ampicillin or erythromycin. Microbial profiling demonstrated a consistent difference between mask types. Cotton masks mainly contained Roseomonas, Paracoccus, and Enhydrobacter taxa and surgical masks Streptococcus and Staphylococcus. After 4 h of mask wearing, the microbiome of the anterior nares and the cheek showed a trend toward an altered beta-diversity. According to dedicated questions in the large-scale Corona survey of the University of Antwerp with almost 25,000 participants, only 21% of responders reported to clean their cotton face mask daily. Laboratory results indicated that the best mask cleaning methods were boiling at 100°C, washing at 60°C with detergent or ironing with a steam iron. Taken together, this study suggests that a considerable number of bacteria, including pathobionts and antibiotic resistant bacteria, accumulate on surgical and even more on cotton face masks after use. Based on our results, face masks should be properly disposed of or sterilized after intensive use. Clear guidelines for the general population are crucial to reduce the bacteria-related biosafety risk of face masks, and measures such as physical distancing and increased ventilation should not be neglected when promoting face mask use.

Efficacy of different antibiotics in treatment of children with respiratory mycoplasma infection

BACKGROUND

Respiratory infections in children are common pediatric diseases caused by pathogens that invade the respiratory system. Children are considerably susceptible to Mycoplasma pneumoniae infection. There has been widespread clinical attention on treatment strategies for this disease.

AIM

To analyze the clinical efficacy of different antibiotics in treating pediatric respiratory mycoplasma infections.

METHODS

We included 106 children with a confirmed diagnosis of respiratory mycoplasma infection who were admitted to our hospital from April 2017 to July 2019 and grouped them using a random number table. Among them, 53 children each received clarithromycin or erythromycin. The clinical efficacy of both drugs was evaluated and compared. We performed the multiplex polymerase chain reaction (MP-PCR) test and determined the MP-PCR negative rate in children after the end of the treatment course. We compared the incidence of toxic and side effects, including nausea, diarrhea, and abdominal pain; further, we recorded the length of hospitalization, antipyretic time, and drug costs. Additionally, we evaluated and compared the compliance of the children during treatment.

RESULTS

The erythromycin group showed a significantly higher total effective rate of clinical treatment than the clarithromycin group. MP-PCR test results showed that the clarithromycin group had a significantly higher MP-PCR negative rate than the erythromycin group. Moreover, children in the clarithromycin group had shorter fever time, shorter hospital stays, and lower drug costs than those in the erythromycin group. The clarithromycin group had a significantly higher overall drug adherence rate than the erythromycin group. The incidence of toxic and side effects was significantly lower in the clarithromycin group than in the erythromycin group (P < 0.05).

CONCLUSION

Our findings indicate that clarithromycin has various advantages over erythromycin, including higher application safety, stronger mycoplasma clearance, and higher medication compliance in children; therefore, it can be actively promoted.

Preparation of DNA aptamer and development of lateral flow aptasensor combining recombinase polymerase amplification for detection of erythromycin

Erythromycin has polluted our aquatic environment for decades, leading to the risk of bacterial resistance and harmful effects on human beings, wildlife and ecosystem. There is an urgent demand of developing a portable tool capable of detecting erythromycin on site. In this study, ten aptamer candidates against erythromycin were prepared through Capture-SELEX (systematic evolution of ligands by exponential enrichment) process in 20 rounds. Aptamer candidate Ery_06 with the highest enrichment was chosen for further study, whose affinity was characterized by gold nanoparticles colorimetric assay, quartz crystal microbalance with dissipation and agarose chasing diffusion assay. It was determined by SYBR Green I fluorimetric assay that the characterized aptamer binds to erythromycin with high affinity (Kd: 20 ± 9 nM). Its specificity was also characterized by distinguishing erythromycin from different antibiotics tested. A novel lateral flow aptasensor was constructed by using the newly identified aptamer combined with recombinase polymerase amplification (RPA) and lateral flow strip (LFS). Aptamer acted as a sensing element anchoring on the surface of solid phase could be eluted by erythromycin. RPA functioned to amplify and convert the signal to be visible on LFS. The lateral flow was completed in 15 min, achieving a detection limit of 3 pM. The application feasibility of the aptasensor was proved by the detection of tap water samples spiked with erythromycin.

C-Reactive Protein-Based Strategy to Reduce Antibiotic Dosing for the Treatment of Pneumococcal Infection

C-reactive protein (CRP) is a component of innate immunity. The concentration of CRP in serum increases in microbial infections including Streptococcus pneumoniae infection. Employing a mouse model of pneumococcal infection, it has been shown that passively administered human wild-type CRP protects mice against infection, provided that CRP is injected into mice within two hours of administering pneumococci. Engineered CRP (E-CRP) molecules have been reported recently; unlike wild-type CRP, passively administered E-CRP protected mice against infection even when E-CRP was injected into mice after twelve hours of administering pneumococci. The current study was aimed at comparing the protective capacity of E-CRP with that of an antibiotic clarithromycin. We established a mouse model of pneumococcal infection in which both E-CRP and clarithromycin, when used alone, provided minimal but equal protection against infection. In this model, the combination of E-CRP and clarithromycin drastically reduced bacteremia and increased survival of mice when compared to the protective effects of either E-CRP or clarithromycin alone. E-CRP was more effective in reducing bacteremia in mice treated with clarithromycin than in untreated mice. Also, there was 90% reduction in antibiotic dosing by including E-CRP in the antibiotic-treatment for maximal protection of infected mice. These findings provide an example of cooperation between the innate immune system and molecules that prevent multiplication of bacteria, and that should be exploited to develop novel combination therapies for infections against multidrug-resistant pneumococci. The reduction in antibiotic dosing by including E-CRP in the combination therapy might also resolve the problem of developing antibiotic resistance.

Analysis and occurrence of macrolide residues in stream sediments and underlying alluvial aquifer downstream from a pharmaceutical plant

Macrolide antibiotics azithromycin (AZI), erythromycin (ERY) and clarithromycin (CLA) have been recently included in the EU Watch List of contaminants of emerging concern in the aquatic environment. However, their comprehensive assessment in different environmental compartments, by including synthesis intermediates, by-products and transformation products, is still missing. In this work, a novel method, based on pressurized liquid extraction and liquid chromatography-tandem mass spectrometry, was developed and validated for the determination of such an extended range of macrolide residues in sediment and soil samples at low ng/g levels. The method was applied to determine distribution of 13 macrolides in surface and alluvial aquifer sediments collected in a small stream with a history of chronic exposure to wastewater discharges from AZI production. The total concentrations of the target macrolide compounds in surface sediments were up to 29 μg/g and the most prominent individual macrolides were parent AZI, its synthesis intermediate N-demethyl AZI and transformation products decladinosyl AZI and N'-demethyl AZI. Some ERY-related compounds, originating from AZI synthesis, were also frequently detected, though at lower concentration levels (up to 0.31 ng/g in total). The distribution of macrolide residues in surface sediments indicated their active longitudinal transport by resuspension and redeposition of the contaminated sediment particles. The vertical concentration profiles in stream sediments and the underlying alluvial aquifer revealed that macrolide residues reached deeper alluvial sediments (up to 5 m). Moreover, significant levels of macrolides were found in groundwater samples below the streambed, with the total concentrations reaching up to 1.7 μg/L. This study highlights the importance of comprehensive chemical characterization of the macrolide residues, which were shown to persist in surface and alluvial aquifer sediment more than ten years after their discharge into the aquatic environment.

Gibbosolide A, a highly functionalized 20-membered macrolide with a terminal cis-fused 2-methylhexahydro-2H-furo[3,2-b]pyran motif: insights into late-stage cyclization of marine macrolides

The planar structure and absolute configuration of a sailboat-shaped marine macrolide, featuring twelve carbon stereocenters and a cis-fused ether ring juncture, were unambiguously established by a combined approach of chemistry and spectroscopy.

Macrocyclic sulfone derivatives: Synthesis, characterization, in vitro biological evaluation and molecular docking

An artificial series of macrocycles based on 4,4'-sulfonyldiphenol intermediate was synthesized using a multistep procedure involving oxidation of bisphenol sulfide, etherification of phenolic hydroxyl groups, and final ring closure with different diamines. Different chemical species having aromatic, heteroaromatic, and aliphatic characters were incorporated into macrocyclic frameworks in the final step of ring closure. This simple and easily executable synthetic strategy was applied to synthesize 15 macrocycles (5a-o) in excellent yields. Characterization of the synthesized products was achieved through well-known modern spectroscopic techniques such as IR, NMR, and Mass. Macrocycles 5m and 5n were found to show significant AChE inhibition with IC₅₀ values of 76.9 ± 0.24 and 71.2 ± 0.77 μM, respectively. Macrocycle 5n was also found to be an active inhibitor of butyrylcholinesterase (BChE) with IC₅₀ score of 55.3 ± 0.54 μM. Among others, macrocycle 5l cyclized with o-phenylenediamine demonstrated moderate inhibition with IC₅₀ value of 81.1 ± 0.54 μM. Increasing interest in studying interactions of macrocycles with different enzymatic targets compelled us to design and synthesize sulfone-based macrocycles that might prove as highly potent class of biologically active compounds.

The Synergistic Effect of Mud Crab Antimicrobial Peptides Sphistin and Sph12-38 With Antibiotics Azithromycin and Rifampicin Enhances Bactericidal Activity Against Pseudomonas Aeruginosa

Overuse or abuse of antibiotics has undoubtedly accelerated the increasing prevalence of global antibiotic resistance crisis, and thus, people have been trying to explore approaches to decrease dosage of antibiotics or find new antibacterial agents for many years. Antimicrobial peptides (AMPs) are the ideal candidates that could kill pathogens and multidrug-resistant bacteria either alone or in combination with conventional antibiotics. In the study, the antimicrobial efficacy of mud crab Scylla paramamosain AMPs Sphistin and Sph₁₂₋₃₈ in combination with eight selected antibiotics was evaluated using a clinical pathogen, Pseudomonas aeruginosa. It was interesting to note that the in vitro combination of rifampicin and azithromycin with Sphistin and Sph₁₂₋₃₈ showed significant synergistic activity against P. aeruginosa. Moreover, an in vivo study was carried out using a mouse model challenged with P. aeruginosa, and the result showed that the combination of Sph₁₂₋₃₈ with either rifampicin or azithromycin could significantly promote the healing of wounds and had the healing time shortened to 4–5 days compared with 7–8 days in control. The underlying mechanism might be due to the binding of Sphistin and Sph₁₂₋₃₈ with P. aeruginosa lipopolysaccharides (LPS) and subsequent promotion of the intracellular uptake of rifampicin and azithromycin. Taken together, the significant synergistic antibacterial effect on P. aeruginosa in vitro and in vivo conferred by the combination of low dose of Sphistin and Sph₁₂₋₃₈ with low dose of rifampicin and azithromycin would be beneficial for the control of antibiotic resistance and effective treatment of P. aeruginosa-infected diseases in the future.

Study protocol: azithromycin therapy for chronic lung disease of prematurity (AZTEC) - a randomised, placebo-controlled trial of azithromycin for the prevention of chronic lung disease of prematurity in preterm infants

INTRODUCTION

Chronic lung disease of prematurity (CLD), also known as bronchopulmonary dysplasia (BPD), is a cause of significant respiratory morbidity in childhood and beyond. Coupled with lung immaturity, infections (especially by Ureaplasma spp) are implicated in the pathogenesis of CLD through promotion of pulmonary inflammation. Azithromycin, which is a highly effective against Ureaplasma spp also has potent anti-inflammatory properties. Thus, azithromycin therapy may improve respiratory outcomes by targeting infective and inflammatory pathways. Previous trials using macrolides have not been sufficiently powered to definitively assess CLD rates. To address this, the azithromycin therapy for chronic lung disease of prematurity (AZTEC) trial aims to determine if a 10-day early course of intravenous azithromycin improves rates of survival without CLD when compared with placebo with an appropriately powered study.

METHODS AND ANALYSIS

796 infants born at less than 30 weeks' gestational age who require at least 2 hours of continuous respiratory support within the first 72 hours following birth are being enrolled by neonatal units in the UK. They are being randomised to receive a double-blind, once daily dose of intravenous azithromycin (20 mg/kg for 3 days, followed by 10 mg/kg for a further 7 days), or placebo. CLD is being assessed at 36 weeks' PMA. Whether colonisation with Ureaplasma spp prior to randomisation modifies the treatment effect of azithromycin compared with placebo will also be investigated. Secondary outcomes include necrotising enterocolitis, intraventricular/cerebral haemorrhage, retinopathy of prematurity and nosocomial infections, development of antibiotic resistance and adverse reactions will be monitored.

ETHICS AND DISSEMINATION

Ethics permission has been granted by Wales Research Ethics Committee 2 (Ref 18/WA/0199), and regulatory permission by the Medicines and Healthcare Products Regulatory Agency (Clinical Trials Authorisation reference 21323/0050/001-0001). The study is registered on ISRCTN (ISRCTN11650227). The study is overseen by an independent Data Monitoring Committee and an independent Trial Steering Committee. We shall disseminate our findings via national and international peer-reviewed journals, and conferences. A summary of the findings will also be posted on the trial website.

Study of the Interaction of Zinc Cation with Azithromycin and its Significance in the COVID-19 Treatment: A Molecular Approach

Introduction:

On account of the current COVID-19 pandemic, we have explored the importance of azithromycin and zinc in the treatment of the coronavirus disease by studying the interaction between the cation Zn++ and azithromycin with the tools of the semi-empirical quantum mechanics PM3 method.

Methods:

By this approach, the niche in which Zn++ is located was determined. Zn++ creates a strong clastic binding between an amine and a hydroxyl group located on the amino-hexose side-chain. Such an interaction serves as a shuttle and allows zinc cation to invade endocellular structures.

Results:

In this triple collaborative association, the role of hydroxychloroquine would be more that of a chaotropic agent at plasmic membranes, which facilitates access to the azithromycin-Zn++ equipage into key internal compartments.

Conclusion:

Finally, we show that both azithromycin and Zn++ are susceptible to play a direct role against the replication and the assembly of SARS-CoV-2 particles.

Life-long antimicrobial therapy: where is the evidence?

The decision to prescribe long-term or 'life-long' antibiotics in patients requires careful consideration by the treating clinician. While several guidelines exist to help assist in this decision, the long-term consequences are yet to be well studied. In this review, we aim to provide a summary of the available evidence for patient populations where long-term antibiotic therapy is currently recommended in clinical practice. We will also discuss the pitfalls of this approach, including medication adverse effects, economic cost and any possible contribution to the emerging epidemic of microbial resistance.

Adsorptive removal of azithromycin from aqueous solutions using raw and saponin-modified nano diatomite

This study aims to investigate the performance and mechanism of raw (R-ND) and saponin-modified nano diatomite (M-ND) in the removal of azithromycin from aqueous solutions. Adsorbent characterization was performed using X-ray fluorescence, Brunauer-Emmett-Teller (BET), scanning electron spectroscopy, dynamic light scattering and energy-dispersive X-ray analyses. It was shown that the specific surface area of R-ND was 119.5 m²/g, 14-fold higher than that for raw diatomite, and for M-ND it was 90.1 m²/g. Various adsorption conditions, i.e. adsorbent dosage, pH, initial concentration and contact time were investigated. According to the results, despite reducing the specific surface area by 25%, modification of nano diatomite by saponin markedly enhanced its performance in the removal of azithromycin. The maximum adsorption capacity of R-ND and M-ND in the removal of azithromycin was 68 and 91.7 mg/g, respectively. Fourier transform infrared spectroscopy results revealed that azithromycin was adsorbed by O-H groups on the diatomite surface. Weber-Morris intra-particle diffusion (IPD) model suggested that while IPD is not the rate-controlling step in high concentrations of azithromycin, it is the only step that controls the rate of adsorption in low concentrations. In comparison to R-ND, M-ND showed a higher efficiency in the removal of azithromycin and, therefore, it can be used as a promising low-cost adsorbent to remove azithromycin from aqueous solutions.

Brief Overview of Frequently used Macrolides and Analytical Techniques for their Assessment

Background:

Macrolide antibiotics are known as versatile broad-spectrum antibiotics. Macrolides belong to the oldest group of antibacterial agents. The macrolides which are frequently used for clinical purposes are broadly categorized in three classes depending on the number of membered macrocyclic lactone ring. These three classes actually consist of 14, 15 or 16 atoms in macrocyclic lactone ring which are linked through glycosidic bonds. Erythromycin, azithromycin clarithromycin and roxithromycin are frequently used to control against bacterial infections.

Methods:

The quality assurance and quality controls are important tasks in the pharmaceutical industries. Consequently, to check the quality of drugs, there is a strong need to know about alternative analytical methods for the routine analysis. Many methods have been reported in the literature for the quantitative determination of erythromycin, clarithromycin, azithromycin and clarithromycin in pharmaceutical formulations and biological samples.

Results:

This review will cover a brief introduction of erythromycin, azithromycin, clarithromycin and roxithromycin as well as analytical techniques for their assessment. Each developed method has its own merits and demerits.

Conclusion:

Any accurate method could be used for the quality control and quality assurance of macrolide antibiotics according to the availability, performance and procedure of selected instrument as well as skill and expertise of the analyst.

Nontuberculous mycobacterial infections of the lower extremities: A 15-year experience

Objectives

Nontuberculous mycobacterial infection (NTMI), which is increasing in prevalence, is challenging to diagnose and manage despite the availability of capable laboratories because of subtle and nonspecific clinical findings and nonstandardized treatment guidelines. We aimed to present our experience with lower-extremity NTMI and to compare clinical characteristics and treatment outcomes between immunocompetent and immunocompromised patients.

Methods

To determine clinical presentations and outcomes, we reviewed electronic health records of all patients with lower-extremity NTMI treated and followed up at our institution from January 2002 through December 2017.

Results

Twenty-four patients were included in this study. Mean (SD) age was 58 (19) years. Eighteen patients (75%) were men; 13 (54%) were immunocompetent; and 9 (37%) had bone and joint involvement. No significant differences existed between immunocompetent and immunocompromised patients, except immunocompetent patients had significantly more infections at the hip, thigh, and toe. Bone and joint infection required significantly longer treatment time than skin and soft-tissue infection.

Conclusions

Regardless of immune status, patients with lower-extremity NTMI had similar characteristics, treatments, and outcomes. However, immunosuppression can be a major risk factor in the development of disseminated NTMI and associated complications. Acid-fast bacilli culture is strongly recommended for evaluation of delayed or nonhealing lesions. Aggressive medical and surgical management can be associated with good clinical outcomes.

Encapsulation of erythromycin and bacitracin antibiotics into natural sporopollenin microcapsules: antibacterial, cytotoxicity, in vitro and in vivo release studies for enhanced bioavailability

Nature produces large quantities of superbly complex and highly reliable microcapsules. The micrometre-sized Lycopodium clavatum spores are one example of these robust capsules. The encapsulation of erythromycin (EM) and bacitracin (BAC) antibiotics into the Lycopodium clavatum sporopollenin (LCS) extracted from these spore species is explored for the first time. The LCS microparticles are extensively characterised before and after loading using SEM, CLSM, TGA and FTIR techniques. The loading capacity and entrapping efficiency of EM were 16.2 and 32.4%, respectively. The antibacterial activities of pure antibiotics, empty LCS and the antibiotic-loaded LCS were evaluated against Staphylococcus aureus (Gram-positive), Pseudomonas aeruginosa (Gram-negative), and Klebsiella pneumoniae (Gram-negative) human pathogenic bacterial strains. A remarkable increase in the antibacterial fold activity of both EM- and BAC-loaded LCS compared to that of the pure antibiotics is observed. Crucial for drug delivery applications, empty LCS, EM- and BAC-loaded LCS were found to be nontoxic against human epithelial colorectal adenocarcinoma cells Caco-2 as revealed by the cytotoxicity evaluation. The in vitro release mechanism of EM in pH 7.4 showed a deviation from Fick's law. In vivo release of EM from EM-loaded LCS (an oral dose of 50 mg kg-1) revealed high values of the area under the plasma concentration-time curve (AUC0-6 h and AUC0-∞ were 1620 and 2147 μg h L-1, respectively) indicative of the enhanced EM bioavailability. The successful loading of antibiotics into the nontoxic LCS and the enhanced bioavailability can open up intriguing applications in oral and topical drug delivery strategies.

Context-Specific Action of Ribosomal Antibiotics

The ribosome is a major antibiotic target. Many types of inhibitors can stop cells from growing by binding at functional centers of the ribosome and interfering with its ability to synthesize proteins. These antibiotics were usually viewed as general protein synthesis inhibitors, which indiscriminately stop translation at every codon of every mRNA, preventing the ribosome from making any protein. However, at each step of the translation cycle, the ribosome interacts with multiple ligands (mRNAs, tRNA substrates, translation factors, etc.), and as a result, the properties of the translation complex vary from codon to codon and from gene to gene. Therefore, rather than being indiscriminate inhibitors, many ribosomal antibiotics impact protein synthesis in a context-specific manner. This review presents a snapshot of the growing body of evidence that some, and possibly most, ribosome-targeting antibiotics manifest site specificity of action, which is modulated by the nature of the nascent protein, the mRNA, or the tRNAs.

Antibiotics for prolonged wet cough in children

BACKGROUND

Cough is a frequent symptom presenting to doctors. The most common cause of childhood chronic (greater than fours weeks' duration) wet cough is protracted bacterial bronchitis (PBB) in some settings, although other more serious causes can also present this way. Timely and effective management of chronic wet or productive cough improves quality of life and clinical outcomes. Current international guidelines suggest a course of antibiotics is the first treatment of choice in the absence of signs or symptoms specific to an alternative diagnosis. This review sought to clarify the current evidence to support this recommendation.

OBJECTIVES

To determine the efficacy of antibiotics in treating children with prolonged wet cough (excluding children with bronchiectasis or other known underlying respiratory illness) and to assess risk of harm due to adverse events.

SEARCH METHODS

We undertook an updated search (from 2008 onwards) using the Cochrane Airways Group Specialised Register, Cochrane Register of Controlled Trials (CENTRAL), MEDLINE, Embase, trials registries, review articles and reference lists of relevant articles. The latest searches were performed in September 2017.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing antibiotics with a placebo or a control group in children with chronic wet cough. We excluded cluster and cross-over trials.

DATA COLLECTION AND ANALYSIS

We used standard methods as recommended by Cochrane. We reviewed results of searches against predetermined criteria for inclusion. Two independent review authors selected, extracted and assessed the data for inclusion. We contacted authors of eligible studies for further information as needed. We analysed data as 'intention to treat.'

MAIN RESULTS

We identified three studies as eligible for inclusion in the review. Two were in the previous review and one new study was included. We considered the older studies to be at high or unclear risk of bias whereas we judged the newly included study at low risk of bias. The studies varied in treatment duration (from 7 to 14 days) and the antibiotic used (two studies used amoxicillin/clavulanate acid and one used erythromycin).We included 190 children (171 completed), mean ages ranged from 21 months to six years, in the meta-analyses. Analysis of all three trials (190 children) found that treatment with antibiotics reduced the proportion of children not cured at follow-up (primary outcome measure) (odds ratio (OR) 0.15, 95% confidence interval (CI) 0.07 to 0.31, using intention-to -treat analysis), which translated to a number needed to treat for an additional beneficial outcome (NNTB) of 3 (95% CI 2 to 4). We identified no significant heterogeneity (for both fixed-effect and random-effects model the I² statistic was 0%). Two older trials assessed progression of illness, defined by requirement for further antibiotics (125 children), which was significantly lower in the antibiotic group (OR 0.10, 95% CI 0.03 to 0.34; NNTB 4, 95% CI 3 to 5). All three trials (190 children) reported adverse events, which were not significantly increased in the antibiotic group compared to the control group (OR 1.88, 95% CI 0.62 to 5.69). We assessed the quality of evidence GRADE rating as moderate for all outcome measures, except adverse events which we assessed as low quality.

AUTHORS' CONCLUSIONS

Evidence suggests antibiotics are efficacious for the treatment of children with chronic wet cough (greater than four weeks) with an NNTB of three. However, antibiotics have adverse effects and this review reported only uncertainty as to the risk of increased adverse effects when they were used in this setting. The inclusion of a more robust study strengthened the previous Cochrane review and its results.

Clarithromycin as the empiric antibiotic therapy for medication-related osteonecrosis of the jaw in multiple myeloma patients

About half of individuals diagnosed with medication-related osteonecrosis of the jaw (MRONJ) are multiple myeloma (MM) patients, and most are treated using antibiotics for long-term courses. The penicillin group is recommended as the empiric drug of choice, and quinolones, metronidazole, clindamycin, doxycycline, and erythromycin as alternatives. This paper suggests the macrolide clarithromycin as the empiric antibiotic therapy of MRONJ in MM patients because of its better pharmacologic properties in comparison to erythromycin, and the beneficial effect of this agent in MM. This empiric antibiotic regimen should be later adjusted according to the response and findings of the microbial cultures.

Tear Concentrations of Azithromycin following Topical Administration of a Single Dose of Azithromycin 0.5%, 1.0%, and 1.5% Eyedrops (T1225) in Healthy Volunteers

Purpose

To evaluate azithromycin tear concentrations after one drop of T1225 0.5%, 1.0%, and 1.5% eyedrops.

Methods

In this randomized, double-masked study, 91 healthy volunteers received one drop into each eye of T1225 0.5% (n=23), T1225 1.0% (n=38), or T1225 1.5% (n=38). Azithromycin tear concentrations were measured by HPLC-MS at seven time points for 24 hours. Tolerability was evaluated.

Results

T1225 1.0% and 1.5% had similar pharmacokinetic profiles. After a post-instillation peak (167 to 178 mg/L after 10 minutes), mean concentrations remained above 7 mg/L for 24 hours (except for T1225 1% at H24). A delayed increase of the azithromycin mean tear concentration might be explained by the known late azithromycin release from tissues after storage in cells. Areas under inhibitory curve (AUICs) of T1225 1.0% and 1.5% were higher than AUICs of T1225 0.5% and ranged between 47 and 90. The three T1225 concentrations were safe for the ocular surface.

Conclusions

Once daily instillation of T1225 1.0% and 1.5% was shown to reach an AUIC markedly above the required threshold for an antibacterial activity against Gram-positive bacteria (25–35). These results suggest that a BID instillation is more likely to ensure antimicrobial activity against Gram-negative bacteria (threshold >100).

State of the art: systemic rosacea management

Based on numerous trials, oral tetracyclines and most commonly their second-generation derivative doxycycline have become the main pillar in systemic rosacea treatment. However, the only preparation that has been approved so far in this setting is 40 mg doxycycline in an anti-inflammatory dosage and with a modified release formulation. With the introduction of this once-daily, non-antibiotic dosing of doxycycline, oral therapy is more commonly prescribed as first-line treatment in moderate to severe papulopustular rosacea. In addition, topical and oral strategies are often used in combination due to the more substantial improvements compared to monotherapy. Although several other non-approved oral agents like macrolides, isotretinoin, and carvedilol have been evaluated for systemic treatment and showed promising results, yet the experience with these drugs in rosacea is limited, and thus they should be reserved for special situations.

Effects of clarithromycin treatment in scrub typhus in children: comparison with chloramphenicol and azithromycin

PURPOSE

Chloramphenicol and tetracycline are not recommended for treating scrub typhus in pediatric patients because of potential side effects, such as aplastic anemia or tooth discoloration. While clarithromycin has recently been used in adults, few reports have been published on its effects in pediatric patients. We report the clinical profiles of pediatric scrub typhus and the effects of clarithromycin on scrub typhus in children.

METHODS

We retrospectively analyzed medical records of 56 children with scrub typhus who were admitted between 2004 and 2013 to Chonbuk National University Hospital, Jeonju, Korea. Cases were divided into 3 groups based on thetreatment drug (chloramphenicol, azithromycin, and clarithromycin). We compared their clinical manifestations and laboratory findings.

RESULTS

All patients exhibited fever and rash. Other common clinical manifestations were eschars (66%), lymphadenopathy (48%), upper respiratory symptoms (42%), abdominal pain (32%), and hepatosplenomegaly (14%). Elevated levels of C-reactive protein, erythrocyte sedimentation rates, aspartate transaminase, and alanine transaminase were detected in 95%, 96%, 84%, and 77% of patients, respectively. Additionally, decreased platelet and white blood cell levels were observed in 43% and 36% of patients, respectively. There were no statistical differences between the treatment groups in mean age (P=0.114) or sex (P=0.507). However, time to defervescence after the treatments differed significantly, being the shortest in the clarithromycin group (P=0.019). All patients recovered without complications related to the disease or drugs.

CONCLUSION

Clarithromycin was as effective as chloramphenicol and azithromycin in pediatric scrub typhus patients and may be used as a first-line treatment drug.

Erythromycin Modification That Improves Its Acidic Stability while Optimizing It for Local Drug Delivery

The antibiotic erythromycin has limited efficacy and bioavailability due to its instability and conversion under acidic conditions via an intramolecular dehydration reaction. To improve the stability of erythromycin, several analogs have been developed—such as azithromycin and clarithromycin—which decrease the rate of intramolecular dehydration. We set out to build upon this prior work by developing a conjugate of erythromycin with improved pH stability, bioavailability, and preferential release from a drug delivery system directly at the low pH of an infection site. To develop this new drug conjugate, adamantane-1-carbohydrazide was covalently attached to erythromycin via a pH-degradable hydrazone bond. Since Staphylococcus aureus infection sites are slightly acidic, the hydrazone bond will undergo hydrolysis liberating erythromycin directly at the infection site. The adamantane group provides interaction with the drug delivery system. This local delivery strategy has the potential of reducing off-target and systemic side-effects. This work demonstrates the synthesis of a pH-cleavable, erythromycin conjugate that retains the inherent antimicrobial activity of erythromycin, has an increased hydrophobicity, and improved stability in acidic conditions; thereby enhancing erythromycin’s bioavailability while simultaneously reducing its toxicity.

Antibacterial, antifungal and antimycobacterial compounds from cyanobacteria

Infections from multidrug resistant (MDR) pathogenic bacteria, fungi and Mycobacterium tuberculosis remain progressively intractable. The search of effective antimicrobials from other possible non-conventional sources against MDR pathogenic bacteria, fungi and mycobacteria is call of the day. This review considers 121 cyanobacterial compounds or cyano-compounds with antimicrobial activities. Chemical structures of cyano-compounds were retrieved from ChemSpider and PubChem databases and were visualized by the software ChemDraw Ultra. Chemical information on cyano-compounds pertaining to Lipinski rules of five was assessed. The reviewed cyano-compounds belong to the following chemical classes (with examples): alkaloids (ambiguine isonitriles and 12-epi-hapalindole E isonitrile), aromatic compounds (benzoic acid and cyanobacterin), cyclic depsipeptides (cryptophycin 52 and lyngbyabellin A), cyclic peptides (calophycin and tenuecyclamides), cyclic undecapeptides (kawaguchipeptins and lyngbyazothrin A), cyclophane (carbamidocyclophane), extracellular pigment (nostocine A), fatty acids (alpha-dimorphecolic acid and majusculonic acid), linear peptides (muscoride A), lipopeptides (fischerellins and scytonemin A), nucleosides (tolytoxin and tubercidin), phenols (ambigols and 4-4'-hydroxybiphenyl), macrolides (scytophycin A and tolytoxin), polyketides (malyngolide and nostocyclyne), polyphenyl ethers (crossbyanol A), porphinoids (tolyporphin J) and terpenoids (noscomin and scytoscalarol). Cyanobacteria appear to be a diverse source of compounds with antimicrobial activity. Further attention is required to elucidate whether those could be applied as pharmaceuticals.

A DFT study on the kinetics and mechanism of cyclodiglycine thermal decomposition in the gas phase

Theoretical investigations using density functional theory have been performed on the kinetics and mechanism of cyclodiglycine (piperazine-2,5-dione) thermal decomposition in the gas phase. Five major possible paths have been proposed and analysed. α-Lactam, β-lactam, 4-imidazolidinone and smaller species such as HNCO, H2CNH, H2CCO, CO, H2 and HCN can be produced through these paths. The route yielding aziridine and HNCO is the optimum channel for this reaction from the energy point of view. Finally, according to the quantum theory of atoms in molecules, electron localisation function and localised orbital locator analyses, it was confirmed that a concerted mechanism operates for the reaction and all critical bonds of the transition states have covalent character.

Scrub typhus in pregnancy: Maternal and fetal outcomes

Scrub typhus is an important unrecognized cause for undifferentiated acute febrile illness in India associated with poor fetal outcomes. Maternal and fetal outcomes among pregnant patients with scrub typhus presenting to a tertiary care university teaching hospital from January 2010 to July 2012 were studied. Scrub typhus was diagnosed by clinical criteria along with scrub ELISA positivity or an eschar. In total, 33 of 738 patients (4.5%) who were diagnosed with scrub typhus were pregnant; 57.6% were in the third trimester, 27.3% in the second, and only 15.2% in the first trimester; 69.7% required admission to intensive care. Mortality was low (3%, n = 1) compared to 12.2% mortality reported previously. All patients were treated with Azithromycin. Poor fetal outcome was observed in 51.5% of these pregnancies with fetal loss occurring in 42.4% and preterm childbirth in 9.1%. Scrub typhus complicating pregnancy is associated with a poor fetal outcome despite treatment with Azithromycin. A majority require intensive care treatment for survival.

Macrolides for chronic asthma

BACKGROUND

Asthma is a chronic disease in which inflammation of the airways causes symptomatic coughing, wheezing, and difficult breathing. The inflammation may have different underlying causes, including a reaction to infection in the lungs. Macrolides are antibiotics with antimicrobial and antiinflammatory activities that have been used long-term to control asthma symptoms.

OBJECTIVES

To assess the effects of macrolides for managing chronic asthma.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register up to April 2015. We also manually searched bibliographies of previously published reviews and conference proceedings and contacted study authors. We included records published in any language in the search.

SELECTION CRITERIA

Randomised controlled clinical trials involving both children and adults with chronic asthma treated with macrolides versus placebo for more than four weeks .

DATA COLLECTION AND ANALYSIS

Two reviewers independently examined all records identified in the searches then reviewed the full text of all potentially relevant articles before extracting data in duplicate from all included studies.

MAIN RESULTS

Twenty-three studies met the inclusion criteria, randomising a total of 1513 participants to receive macrolide or placebo. The quality of evidence was generally very low due to incomplete reporting of study methodology and clinical data, suspected publication bias, indirectness of study populations, risk of bias and imprecision (because of small numbers of patients and events). Most of the included studies reported data from patients with persistent or severe asthma, but inclusion criteria, interventions and outcomes were highly variable.Macrolides were not found to be better than placebo for the majority of clinical outcomes including exacerbations requiring hospital admission (odds ratio (OR) 0.98, 95% confidence interval (CI) 0.13 to 7.23; participants = 143; studies = 2; I(2) = 0%) or at least treatment with oral steroids (OR 0.82, 95% CI 0.43 to 1.57; participants = 290; studies = 5; I(2) = 0%). The evidence on symptom scales (standard mean difference (SMD) -0.04, 95% CI -0.36 to 0.28), asthma control (SMD -0.05, 95% CI -0.26 to 0.15), quality of life (mean difference (MD) 0.06, 95% CI -0.12 to 0.24) and rescue medication use (MD -0.26, 95% CI -0.65 to 0.12) was all of very low quality and did not show a benefit of macrolide treatment. There was some evidence that macrolides led to some improvement in lung function (forced expiratory volume in one second (FEV1): MD 0.08, 95% CI 0.02 to 0.14), although not on all the measures we assessed. Measures of bronchial hyperresponsiveness were too varied to pool, but most studies showed no clear benefit of macrolide over placebo. Two studies recruiting people taking regular oral corticosteroids suggested macrolides may have a steroid-sparing effect in this population. Macrolides were well tolerated with respect to severe adverse events, although less than half of the studies reported the outcome (OR 0.80, 95% CI 0.24 to 2.68; participants = 434; studies = 7; I(2) = 0%). Reporting of specific side effects was too patchy across studies to analyse meaningfully. As already reported in the previous versions of the systematic review, biomarkers of asthma activity, such as sputum and serum level of eosinophil cationic protein (ECP) or sputum and serum eosinophils, were lower in patients treated with macrolides, but this was not associated with clinical benefits.Two within-study subgroup analyses showed a possible benefit of macrolides for non-eosinophilic asthma, but it was not possible to investigate this further using the data available for this review.

AUTHORS' CONCLUSIONS

Existing evidence does not show macrolides to be better than placebo for the majority of clinical outcomes. However, they may have a benefit on some measures of lung function, and we cannot rule out the possibility of other benefits or harms because the evidence is of very low quality due to heterogeneity among patients and interventions, imprecision and reporting biases.The review highlights the need for researchers to report clinically relevant outcomes accurately and completely using guideline definitions of exacerbations and validated scales. The possible benefit of macrolides in patients with non-eosinophilic asthma based on subgroup analyses in two of the included studies may require further investigation.

Adjuvant Narrow Band UVB Improves the Efficacy of Oral Azithromycin for the Treatment of Moderate to Severe Inflammatory Facial Acne Vulgaris

Background:

Acne vulgaris (AV) is a common inflammatory disease of the pilosebaceous unit. A variety of treatment modalities are available for the treatment of AV. Among the available options, oral azithromycin is popularly prescribed for its proven anti-inflammatory effects. Narrow band UVB (NBUVB) also has a potent anti-inflammatory action. Concomitant use of both modalities may result in a synergistic therapeutic response; however, the combined efficacy has not yet been evaluated for the treatment of inflammatory AV.

Objective:

The aim of this study was to compare the efficacy of oral azithromycin plus NBUVB (peak 311 nm) to oral azithromycin alone for the treatment of moderate to severe inflammatory AV.

Materials and Methods:

A randomized, open-label, clinical trial was conducted over 4 weeks. Subjects were randomized into two groups. Group 1 received 500 mg of oral azithromycin three times per week. Group 2 received 500 mg of oral azithromycin plus NBUVB three and two times per week, respectively. Concomitant topical or oral AV treatments were not permitted during the treatment period. Response to treatment was measured by photographic records at the primary endpoint (2 weeks) and at the end of treatment.

Results:

One hundred and four subjects were enrolled in the trial; 94 subjects completed the treatment period of the study. Group 2 demonstrated significant clinical improvement of the inflammatory papular lesions (88.55%) compared with group 1 (70.34%) at the end of treatment (P = 0.002). The clinical response of pustular (P = 0.562), nodular (P = 0.711) and cystic (P = 0.682) lesions did not significantly differ between the two treatment groups. Interestingly, response to treatment in group 2 had a significant anatomical predilection for the forehead (P = 0.023). There was no side-effect except erythema, which subsided within 1-2 days.

Conclusion:

NBUVB plus oral azithromycin is more effective than oral azithromycin alone for treating papular lesions of inflammatory AV. NBUVB is certainly a viable adjunct in acne therapy.