Presence Of Azithromycin Research Articles

The effect of triple CFTR modulator therapy and azithromycin on ion channels and inflammation in cystic fibrosis

Inflammation in cystic fibrosis (CF) airways is difficult to treat with well-established regimens often including azithromycin (AZ) as an immunomodulatory drug. As AZ has been reported to require CFTR to be able to reduce IL-8 and given the emergence of highly effective CFTR “triple” modulator therapy (elexacaftor/tezacaftor/ivacaftor; ETI), the aim of this study was to investigate the effect of AZ and ETI, singly and in combination, on ion channel activity and to assess potential anti-inflammatory effects. Electrophysiological assessment of ETI and AZ was performed on 3D cultures of primary CF human bronchial epithelial (HBE) cells using Multi Trans-Epithelial Current Clamp (MTECC). IL-8 from NuLi-1 (non-CF) and CuFi-1 (CF) cells treated with AZ was measured by ELISA. Inflammatory mediators from primary CF HBE cells exposed to tumour necrosis factor-alpha (TNF-α) in the presence of AZ, ETI and their combination, were screened using the Proteome Profiler™ Human Cytokine Array Kit, with selected targets validated by ELISA. AZ did not alter CFTR chloride efflux, nor did it have any synergistic/antagonistic effect in combination with ETI. AZ reduced IL-8 in NuLi-1 but not CuFi-1 cells. The Proteome Profiler™ screen identified several disease-relevant cytokines that were modulated by treatment. Subsequent analysis by ELISA showed IL-8, IL-6, CXCL1 and GM-CSF to be significantly reduced by treatment with ETI, but not by AZ. Incorporating ETI into the standard of CF care provides an opportunity to re-evaluate therapeutic regimens to reduce treatment burden and safely discontinue chronic treatments such as AZ, without loss of clinical benefit. Identification of redundant treatments in the era of CFTR modulation may improve medication adherence and overcome potential adverse effects associated with the chronic use AZ and other drugs.

Upregulation of outer membrane porin gene ompC contributed to enhancement of azithromycin susceptibility in multidrug-resistant Escherichia coli.

The outer membrane (OM) in gram-negative bacteria contains proteins that regulate the passive or active uptake of small molecules for growth and cell function, as well as mediate the emergence of antibiotic resistance. This study aims to explore the potential mechanisms for restoring bacteria to azithromycin susceptibility based on transcriptome analysis of bacterial membrane-related genes. Transcriptome sequencing was performed by treating multidrug-resistant Escherichia coli T28R with azithromycin or in combination with colistin and confirmed by reverse transcription-quantitative PCR (RT-qPCR). Azithromycin enzyme-linked immunosorbent assay (ELISA) test, ompC gene overexpression, and molecular docking were utilized to conduct the confirmatory research of the potential mechanisms. We found that colistin combined with azithromycin led to 48 differentially expressed genes, compared to azithromycin alone, such as downregulation of tolA, eptB, lpxP, and opgE and upregulation of ompC gene. Interestingly, the addition of colistin to azithromycin differentially downregulated the mph(A) gene mediating azithromycin resistance, facilitating the intracellular accumulation of azithromycin. Also, overexpression of the ompC elevated azithromycin susceptibility, and colistin contributed to further suppression of the Mph(A) activity in the presence of azithromycin. These findings suggested that colistin firstly enhanced the permeability of bacterial OM, causing intracellular drug accumulation, and then had a repressive effect on the Mph(A) activity along with azithromycin. Our study provides a novel perspective that the improvement of azithromycin susceptibility is related not only to the downregulation of the mph(A) gene and conformational remodeling of the Mph(A) protein but also the upregulation of the membrane porin gene ompC.IMPORTANCEUsually, active efflux via efflux pumps is an important mechanism of antimicrobial resistance, such as the AcrAB-TolC complex and MdtEF. Also, bacterial porins exhibited a substantial fraction of the total number of outer membrane proteins in Enterobacteriaceae, which are involved in mediating the development of the resistance. We found that the upregulation or overexpression of the ompC gene contributed to the enhancement of resistant bacteria to azithromycin susceptibility, probably due to the augment of drug uptakes caused and the opportunity of Mph(A) function suppressed by azithromycin with colistin. Under the combination of colistin and azithromycin treatment, OmpC exhibited an increased selectivity for cationic molecules and played a key role in the restoral of the antibiotic susceptibility. Investigations on the regulation of porin expression that mediated drug resistance would be important in clinical isolates treated with antibiotics.

Divergent effects of azithromycin on purple corn (Zea mays L.) cultivation: Impact on biomass and antioxidant compounds.

The present study assessed the impact of using irrigation water contaminated with Azithromycin (AZM) residues on the biomass and antioxidant compounds of purple corn; for this purpose, the plants were cultivated under ambient conditions, and the substrate used consisted of soil free from AZM residues, mixed with compost in a ratio of 1:1 (v/v). The experiment was completely randomized with four replications, with treatments of 0, 1, 10, and 100 μg/L of AZM. The results indicate that the presence of AZM in irrigation water at doses of 1 and 10 μg/L increases the weight of dry aboveground biomass, while at an amount of 100 μg/L, it decreases. Likewise, this study reveals that by increasing the concentration of AZM from 1 to 10 μg/L, total polyphenols and monomeric anthocyanins double, in contrast, with an increase to 100 μg/L, these decrease by 44 and 53%, respectively. It has been demonstrated that purple corn exposed to the antibiotic AZM at low doses has a notable antioxidant function in terms of DPPH and ORAC. The content of flavonols, phenolic acids, and flavanols increases by 57, 28, and 83%, respectively, when the AZM concentration is from 1 to 10 μg/L. However, with an increase to 100 μg/L, these compounds decrease by 17, 40, and 42%, respectively. On the other hand, stem length, root length, and dry weight of root biomass are not significantly affected by the presence of AZM in irrigation water.

Impact of antibiotics on methane produced from cellulose

Enhancing production of methane from cellulose is of utmost importance to improve the fermentation efficiency of lignocellulosic biomass. Antibiotics have demonstrated their ability to stimulate anaerobic digestion (AD) by influencing micro-organism activity. However, there has been limited research on the specific effect of antibiotics on cellulose AD. In this study, we investigated the impact of three antibiotics—tetracycline (TC), cephalexin (CLX), and azithromycin (AZM)—on cellulose AD when inoculated with waste sewage sludge. The results revealed that the presence of AZM and TC led to significantly higher methane yields, with increases of 51.94% and 34.96%, respectively, during a 20-day AD period. In contrast, the presence of CLX resulted in a 23.95% lower methane yield compared to the control. Furthermore, detailed analyses indicated that AZM had a positive influence on cellulose AD at all stages, including methanogenesis, acidogenesis/acetogenesis, and hydrolysis. On the other hand, TC primarily promoted AD during the methanogenesis stage. These findings collectively offer valuable guidance for efficiently transforming the energy potential of lignocellulosic wastes.

Electrospun Azithromycin-Laden Gelatin Methacryloyl Fibers for Endodontic Infection Control.

This study was aimed at engineering photocrosslinkable azithromycin (AZ)-laden gelatin methacryloyl fibers via electrospinning to serve as a localized and biodegradable drug delivery system for endodontic infection control. AZ at three distinct amounts was mixed with solubilized gelatin methacryloyl and the photoinitiator to obtain the following fibers: GelMA+5%AZ, GelMA+10%AZ, and GelMA+15%AZ. Fiber morphology, diameter, AZ incorporation, mechanical properties, degradation profile, and antimicrobial action against Aggregatibacter actinomycetemcomitans and Actinomyces naeslundii were also studied. In vitro compatibility with human-derived dental pulp stem cells and inflammatory response in vivo using a subcutaneous rat model were also determined. A bead-free fibrous microstructure with interconnected pores was observed for all groups. GelMA and GelMA+10%AZ had the highest fiber diameter means. The tensile strength of the GelMA-based fibers was reduced upon AZ addition. A similar pattern was observed for the degradation profile in vitro. GelMA+15%AZ fibers led to the highest bacterial inhibition. The presence of AZ, regardless of the concentration, did not pose significant toxicity. In vivo findings indicated higher blood vessel formation, mild inflammation, and mature and thick well-oriented collagen fibers interweaving with the engineered fibers. Altogether, AZ-laden photocrosslinkable GelMA fibers had adequate mechanical and degradation properties, with 15%AZ displaying significant antimicrobial activity without compromising biocompatibility.

UHPLC-MS/MS method for the determination of azithromycin in human plasma of pediatric patients.

The presence of azithromycin in the human plasma of pediatric patients was determined with a UHPLC-MS/MS assay. Sample preparation was done by protein precipitation, and the separation was achieved on a C18 column by the gradient mixture of the mobile phase A (0.1% acetic acid and 3mM ammonium acetate in water) and the mobile phase B (0.1% acetic acid and 3mM ammonium acetate in the solution of acetonitrile, methanol, and water, 47.5/47.5/5, V/V/V). The multiple reaction monitoring mode was adopted to monitor the precursor-to-product ion transitions of m/z 749.6 → m/z 591.5 for azithromycin and m/z 753.6 → m/z 595.5 for azithromycin-13 C-d3 (the internal standard) at the positive ionization mode. The calibration curve ranged from 0.5 to 500.0ng·mL-1 , and the correlation coefficient was greater than 0.99. The intra- and inter-batch precision was less than 13.7%. Accuracy determined at four concentrations ranged from 99.5 to 110.8%. The extraction recoveries were more than 95%, and the matrix effects were 98-100%. The stability under various conditions was acceptable with the accuracy deviation within 9.2%. In conclusion, our method was simple, sensitive, and reliable for quantifying azithromycin in plasma among pediatric patients.

Arrhythmogenic mechanisms of interleukin-6 combination with hydroxychloroquine and azithromycin in inflammatory diseases

Inflammatory diseases including COVID-19 are associated with a cytokine storm characterized by high interleukin-6 (IL-6) titers. In particular, while recent studies examined COVID-19 associated arrhythmic risks from cardiac injury and/or from pharmacotherapy such as the combination of azithromycin (AZM) and hydroxychloroquine (HCQ), the role of IL-6 per se in increasing the arrhythmic risk remains poorly understood. The objective is to elucidate the electrophysiological basis of inflammation-associated arrhythmic risk in the presence of AZM and HCQ. IL-6, AZM and HCQ were concomitantly administered to guinea pigs in-vivo and in-vitro. Electrocardiograms, action potentials and ion-currents were analyzed. IL-6 alone or the combination AZM + HCQ induced mild to moderate reduction in heart rate, PR-interval and corrected QT (QTc) in-vivo and in-vitro. Notably, IL-6 alone was more potent than the combination of the two drugs in reducing heart rate, increasing PR-interval and QTc. In addition, the in-vivo or in-vitro combination of IL-6 + AZM + HCQ caused severe bradycardia, conduction abnormalities, QTc prolongation and asystole. These electrocardiographic abnormalities were attenuated in-vivo by tocilizumab (TCZ), a monoclonal antibody against IL-6 receptor, and are due in part to the prolongation of action potential duration and selective inhibition of Na+, Ca2+ and K+ currents. Inflammation confers greater risk for arrhythmia than the drug combination therapy. As such, in the setting of elevated IL-6 during inflammation caution must be taken when co-administering drugs known to predispose to fatal arrhythmias and TCZ could be an important player as a novel anti-arrhythmic agent. Thus, identifying inflammation as a critical culprit is essential for proper management.

Heterogeneity in susceptibility to hydroxychloroquine of SARS-CoV-2 isolates.

Despite the fact that the clinical efficacy of hydroxychloroquine is still controversial, it has been demonstrated in vitro to control SARS-CoV-2 multiplication on Vero E6 cells. In this study, we tested the possibility that some patients with prolonged virus excretion could be infected by less susceptible strains. Using a high-content screening method, we screened 30 different selected isolates of SARS-CoV-2 from different patients who received azithromycin ± hydroxychloroquine. We focused on patients with viral persistence, i.e., positive virus detection in a nasopharyngeal sample ≥10 days, and who were tested during two French epidemic waves, late winter-spring of 2020 and the summer of 2020. Dose-response curves in single-molecule assays with hydroxychloroquine were created for isolates with suspected reduced susceptibility. Genome clustering was performed for all isolates. Of 30 tested strains, three were detected as replicating in the presence of azithromycin + hydroxychloroquine, each at 5 μM. The dose-response model showed a decrease in susceptibility of these three strains to hydroxychloroquine. Whole genome sequencing revealed that these three strains are all from the second epidemic wave and two cluster with isolates from Africa. Reduced susceptibility to hydroxychloroquine was not associated with viral persistence in naso-pharyngeal samples. Rather, it was associated with occurring during the second epidemic wave, which began in the summer and with strains clustering with those with a common genotype in Africa, where hydroxychloroquine was the most widely used.

Azithromycin enhances the cytotoxicity of DNA-damaging drugs via lysosomal membrane permeabilization in lung cancer cells.

Cancer cells use autophagy for growth, survival, and cytoprotection from chemotherapy. Therefore, autophagy inhibitors appear to be good candidates for cancer treatment. Our group previously reported that macrolide antibiotics, especially azithromycin (AZM), have potent autophagy inhibitory effects, and combination treatment with tyrosine kinase inhibitors or proteasome inhibitors enhances their anti–cancer activity. In this study, we evaluated the effect of combination therapy with DNA‐damaging drugs and AZM in non–small‐cell lung cancer (NSCLC) cells. We found that the cytotoxic activities of DNA‐damaging drugs, such as doxorubicin (DOX), etoposide, and carboplatin, were enhanced in the presence of AZM in NSCLC cell lines, whereas AZM alone exhibited almost no cytotoxicity. This enhanced cell death was dependent on wild‐type‐p53 status and autophagosome‐forming ability because TP53 knockout (KO) and ATG5‐KO cells attenuated AZM‐enhanced cytotoxicity. DOX treatment upregulated lysosomal biogenesis by activating TFEB and led to lysosomal membrane damage as assessed by galectin 3 puncta assay and cytoplasmic leakage of lysosomal enzymes. In contrast, AZM treatment blocked autophagy, which resulted in the accumulation of lysosomes/autolysosomes. Thus, the effects of DOX and AZM were integrated into the marked increase in damaged lysosomes/autolysosomes, leading to prominent lysosomal membrane permeabilization (LMP) for apoptosis induction. Our data suggest that concomitant treatment with DNA‐damaging drugs and AZM is a promising strategy for NSCLC treatment via pronounced LMP induction.

Binding and drug displacement study of colchicine and bovine serum albumin in presence of azithromycin using multispectroscopic techniques and molecular dynamic simulation

The binding and displacement interaction of colchicine and azithromycin to the model transport protein bovine serum albumin (BSA) was evaluated in this study. Azithromycin, a macrolide antibiotic, has antiviral properties and hence, has been used concomitantly with hydroxychloroquine against SARS-CoV-2. Colchicine, a natural plant product is used to treat and prevent acute gout flares. Some macrolide antibiotics are reported to have fatal drug-drug interactions with colchicine. The displacement interaction between colchicine and azithromycin on binding to BSA was evaluated using spectroscopic techniques, molecular docking and molecular dynamic simulation studies. The binding constant recorded for the binary system BSA-colchicine was 7.44 × 104 whereas, the binding constant for the ternary system BSA-colchicine in presence of azithromycin was 7.38 × 104 and were similar. Azithromycin didn't bind to BSA neither did it interfere in binding of colchicine. The results from molecular docking studies also led to a similar conclusion that azithromycin didn't interfere in the binding of colchicine to BSA. These findings are important since there is possibility of serious adverse event with co-administration of colchicine and azithromycin in patients with underlying gouty arthritis and these patients need to be continuously monitored for colchicine toxicity.

Use of low frequency ultrasound for water treatment: Data on azithromycin removal.

Azithromycin (AZT) is a broad-spectrum antibiotic present in different aqueous matrices due to its incomplete removal using conventional water treatments. Ultrasound (US) is an advanced oxidation technology that has demonstrated its capacity to degrade different types of organic molecules due to the generation of cavitation bubbles or cavities that promote the generation of radicals.In this paper, data regarding the use of low-frequency US (40 kHz) in the removal of AZT are presented. Tests were carried out at lab scale for 60 min considering a reaction volume of 300 mL (pollutant initial concentration 1.0 mg L−1). The effect of operational parameters such as pH, ultrasound power, the presence of external agents like ferrous ions, hydrogen peroxide, and UV radiation were evaluated. In general, obtained data show that under the experimental reaction conditions, it is feasible to reach extents of AZT removal ∼50.0%, and that the presence of other species in the medium could inhibit the reaction, mainly due to scavenging effects. This information is relevant to future applications of US, at pilot or real scale, in the treatment of water with presence of AZT or similar organic pollutants.

Comparison of autophagy inducibility in various tyrosine kinase inhibitors and their enhanced cytotoxicity via inhibition of autophagy in cancer cells in combined treatment with azithromycin

Tyrosine kinase inhibitors (TKIs) induce autophagy in many types of cancer cells. We previously reported that gefitinib (GEF) and imatinib (IMA) induce autophagy in epidermal growth factor receptor (EGFR) knock-out A549 and non-BCR-ABL-expressing leukemia cell lines, respectively. This evidence suggests that TKI-induced autophagy is independent of the original target molecules. The present study compared the autophagy-inducing abilities of various TKIs, regardless of their targets, by quantitative autophagy flux assay. We established stable clones expressing the GFP-LC3-mCherry-LC3ΔG plasmid in A549, PC-9, and CAL 27 cell lines and assessed autophagy inducibility by monitoring the fluorescent ratios of GFP-LC3 to mCherry-LC3ΔG using an IncuCyte live cell imaging system during exposure to TKIs viz; GEF, osimertinib (OSI), lapatinib (LAP), lenvatinib (LEN), sorafenib (SOR), IMA, dasatinib (DAS), and tivantinib (TIV). Among these TKIs, DAS, GEF, and SOR exhibited prominent autophagy induction in A549 and PC-9 cells. In CAL 27 cells, IMA, SOR, and LEN, but not GEF, TIV, or OSI, exhibited autophagy induction. In the presence of azithromycin (AZM), which showed an inhibitory effect on autophagy flux, TKIs with prominent autophagy inducibility exhibited enhanced cytotoxicity via non-apoptotic cell death relative to effects of TKI alone. Therefore, autophagy inducibility of TKIs differed in the context of cancer cells. However, once induced, they appeared to have cytoprotective functions. Thus, blocking TKI-induced autophagy with AZM may improve the therapeutic effect of TKIs in cancer cells.

Electrochemical investigations of copper corrosion inhibition by azithromycin in 0.9% NaCl

The corrosion behavior of copper in 0.9% NaCl solution in the presence of azithromycin was investigated. For this purpose electrochemical methods such as open circuit potential measurements, potentiodynamic polarization and electrochemical impedance spectroscopy measurements and scanning electron microscopy with energy dispersive X-ray spectroscopy were used. The results obtained by potentiodynamic polarization indicated that azithromycin behaves as mixed type inhibitor. The order of inhibition efficiency obtained by potentiodynamic polarization is in good agreement with results achieved by electrochemical impedance spectroscopy. Also, the inhibition efficiency of azithromycin increases with increasing its concentration. According to the micrographs obtained by scanning electron microscopy with energy dispersive X-ray spectroscopy, in the presence of azithromycin, protective film is formed on the copper surface.

An Antipersister Strategy for Treatment of Chronic Pseudomonas aeruginosa Infections.

Bacterial persisters are a quasidormant subpopulation of cells that are tolerant to antibiotic treatment. The combination of the aminoglycoside tobramycin with fumarate as an antibacterial potentiator utilizes an antipersister strategy that is aimed at reducing recurrent Pseudomonas aeruginosa infections by enhancing the killing of P. aeruginosa persisters. Stationary-phase cultures of P. aeruginosa were used to generate persister cells. A range of tobramycin concentrations was tested with a range of metabolite concentrations to determine the potentiation effect of the metabolite under a variety of conditions, including a range of pH values and in the presence of azithromycin or cystic fibrosis (CF) patient sputum. In addition, 96-well dish biofilm and colony biofilm assays were performed, and the cytotoxicity of the tobramycin-fumarate combination was determined utilizing a lactate dehydrogenase (LDH) assay. Enhanced killing of up to 6 orders of magnitude of P. aeruginosa persisters over a range of CF isolates, including mucoid and nonmucoid strains, was observed for the tobramycin-fumarate combination compared to killing with tobramycin alone. Furthermore, significant fumarate-mediated potentiation was seen in the presence of azithromycin or CF patient sputum. Fumarate also reduced the cytotoxicity of tobramycin-treated P. aeruginosa to human epithelial airway cells. Finally, in mucoid and nonmucoid CF isolates, complete eradication of P. aeruginosa biofilm was observed in the colony biofilm assay due to fumarate potentiation. These data suggest that a combination of tobramycin with fumarate as an antibacterial potentiator may be an attractive therapeutic for eliminating recurrent P. aeruginosa infections in CF patients through the eradication of bacterial persisters.

Antibiotics target MCF-7 breast cancer stem cells in hypoxic environment.

e14068 Background: Deregulated cellular metabolism is characteristic for cancer cells which heavily rely on glycolysis to meet metabolic demands. Studies have shown that increased glucose metabolism promotes tumor cell survival through mechanisms related to mitochondrial activities. Recently, mitochondrial inhibitors have been proposed as a potential anticancer therapeutics. In 2015 Lamb et al. presented anti-cancer activity of several antibiotics targeting mitochondrial function. Interestingly, these drugs have the highest inhibitory effect on cancer stem cells (CSCs), a small population of cancer initiating cells. It is believed that tumor microenvironment plays significant role in maintaining CSC population. The hypoxia is a major feature of the tumor microenvironment contributing into CSC phenotype, tumorigenicity and metastasis. Therefore, we sought to determine the effect of five antibiotics targeting mitochondrial function on CSC survival in hypoxia conditions. Methods: MCF-7 cells were cultured in normoxic (20% O2) and hypoxic (4% O2) conditions for 14 days in a presence of azithromycin, doxycycline, tetracycline, erythromycin and chloramphenicol. The ability to form mammospheres was used to determine CSC survival. Results: Incubation of CSCs with erythromycin, doxycycline, tetracycline and chloramphenicol reduced the number of mammospheres, the decrease in mammosphere number was comparable for MCF-7 cells incubated under normoxic and hypoxic conditions [erythromycin (62.5 % ± 10.8% vs. 58.9% ± 2.2% ), doxycycline (75.2% ± 5.9% vs. 68.5% ± 5.4% ), tetracycline (56.0% ± 3.2% vs. 65.0% ± 15.0%) and chloramphenicol (71.5% ± 6.7% vs. 73.7% ± 5.5%)]. Interestingly, azithromycin did not show inhibiting activity on sphere formation under hypoxic condition, while number of spheres was reduced in normoxic conditions Conclusions: These data indicate that four out of five antibiotics in our study can be potentially applied for targeted eradication of breast CSCs in hypoxiс conditions. Acknowledgements: The study was funded by RFBR, according to the research project No. 16-34-60210 mol_а_dk, and by Russian Government Program of Competitive Growth of Kazan Federal University.

Occurrence and preliminarily environmental risk assessment of selected pharmaceuticals in the urban rivers, China.

Twelve selected pharmaceuticals including antibiotics, analgesics, antiepileptics and lipid regulators were analysed and detected in water samples collected from 18 sampling sections along the three main urban rivers in Yangpu District of Shanghai, China during four sampling campaigns. Besides, algal growth inhibition test was conducted to preliminarily assess the eco-toxicology induced by the target pharmaceuticals in the rivers. Mean levels for most of target compounds were generally below 100 ng/L at sampling sections, with the exception of caffeine and paracetamol presenting considerably high concentration. The detected pharmaceuticals in the urban rivers ranged from <LOQ for propranolol to 8571 ng/L for caffeine. Qiujiang River could be regarded as the most polluted according to total detected pharmaceutical concentrations. The target pharmaceuticals varied and fluctuated irregularly from the upstreams to the downstreams of the three rivers, indicating the wastewater inputs from non-point sources and their individual different characteristics of transference and transportation. Preliminary eco-toxicological risk assessment showed that the presence of azithromycin, clarithromycin and caffeine may present an ecotoxicological risk in the urban rivers. For other tested pharmaceuticals the inhibition effects of single substances in the urban aquatic environment, based on the algae inhibition tests, were very imperceptible.

Azithromycin recovers reductions in barrier function in human gingival epithelial cells stimulated with tumor necrosis factor-α

ObjectiveThe gingival epithelium plays an important role in protecting against the invasion of periodontal pathogens, and the permeability of gingival epithelial cells has been implicated in the initiation of periodontitis. Azithromycin (AZM) has been used in the treatment of chronic inflammatory airway diseases because it regulates cell–cell contact in airway epithelial cells. Therefore, AZM may also regulate barrier function in gingival epithelial cells. In the present study, we examined the effects of AZM on the permeability of human gingival epithelial cells (HGEC) under inflammatory conditions in vitro. Materials and methodsHGEC were stimulated by tumor necrosis factor-α (TNF-α) in the presence of AZM or p38 MAP kinase and ERK inhibitors. Permeability was assessed based on transepithelial electrical resistance (TER). The expression of E-cadherin, phosphorylated p38 MAP kinase, and ERK was analyzed by Western blotting. ResultsTNF-α decreased TER in HGEC, and AZM and the p38 MAP kinase and ERK inhibitors recovered this decrease. AZM inhibited the phosphorylation of ERK and p38 MAP kinase in TNF-α-stimulated HGEC. Furthermore, AZM recovered the decrease in E-cadherin expression in HGEC stimulated with TNF-α. Conclusions: These results suggested that AZM regulated gingival epithelial permeability through p38 MAP kinase and ERK signaling, and may contribute to suppress the inflammation in gingival tissue.

Chemical and Electrochemical studies on the corrosion of mild-steel, copper and zinc in 0. 5 M H2SO4 solution in presence of Azithromycin as effective corrosion inhibitor

Azithromycin has been tested as inhibitor for steel, copper and zinc corrosion in 0.5 M H2SO4 was studied using potentiodynamic polarization and electrochemical impedance spectroscopy. The results showed that the inhibition efficiency increased with increasing the concentration of Azithromycin. The adsorption characteristics of Azithromycin in presence of steel, copper and zinc metals were studied and the data found to fit the Kinetic-Thermodynamic model. IR spectroscopy of the corrosion product with the inhibitor confirmed the formation of metal ion inhibitor complex.

Regulation of biofilm formation by Pseudomonas chlororaphis in an in vitro system

The mutants of Pseudomonas chlororaphis 449 with completely or partially suppressed accumulation of N-acyl homoserine lactones exhibited the absence or a pronounced decrease of their capacity for stimulation of biofilm growth in the presence of azithromycin. Biofilms of the wild type strain preformed in the presence of the stimulatory azithromycin concentrations exhibited more intense staining with a polysaccharide-specific dye 1,9-dimethyl methylene blue (DMMB) and were more resistant to heat shock. These findings indicate accumulation of the structural matrix polysaccharides, which play a protective role under the conditions of thermal shock. Extremely low azithromycin concentrations (0.001-0.01 μg/mL) inhibit biofilm formation by P. chlororaphis 449 and P. chlororaphis 66 with suppression of the synthesis of DMMB-staining polysaccharides.

Influence of sub-inhibitory antibiotics and flow condition on Staphylococcus aureus ATCC 6538 biofilm development and biofilm growth rate: BioTimer assay as a study model.

Staphylococcus biofilm exhibits high antibiotic resistance and therapeutic doses of antibiotics are often sub-inhibitory. Whereas data are available on the effect of sub-inhibitory antibiotics on matrix formation, little is known on their influence on biofilm population. Here, using BioTimer Assay (BTA), a method developed to quantify biofilm population, the influence of sub-inhibitory gentamicin, ofloxacin and azithromycin on Staphylococcus aureus ATCC 6538 biofilm population in flow with respect to static condition was assessed. Antibiotics and flow condition increased biofilm population even if at different extent, depending on the antibiotic molecule. The greatest bacterial population was found in biofilm developed under flow condition in the presence of azithromycin. A significant increase in biofilm matrix was recorded for biofilm developed in the presence of antibiotics in flow with respect to static condition. The growth rates (GRs) of 24-h biofilm developed under the influence of antibiotics and flow condition were also evaluated using BTA and a specific mathematical model. Antibiotics and flow condition affected the GRs of 24-h biofilm even if at different extent. The lowest GR value was recorded for biofilm developed under flow condition in the presence of ofloxacin. Although further studies are needed, our data indicate that antibiotics and flow condition influenced biofilm development by increasing both bacterial population and matrix formation and affected the GRs of the developed biofilm. To the best of our knowledge, BTA is unique in allowing the calculation of the GRs of biofilm and it may be considered to be a useful study model to evaluate the activity of antibiofilm molecules.