Concentrations Of Antibacterial Agents Research Articles

Screening of Antimicrobial Properties and Bioactive Compounds of Pleurotus Ostreatus Extracts against Staphylococcus Aureus, Escherichia coli, and Neisseria Gonorrhoeae.

In recent years, the potential of pathogenic bacteria to acquire resistance to a variety of antimicrobial drugs has developed significantly due to the indiscriminate exposure of a number of antibiotic compounds. The purpose of this study is to determine the antibacterial capabilities and activities of crude Pleurotus ostreatus extracts against Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), Neisseria gonorrhoeae (ATCC 49926), and nine multidrug-resistant clinical isolates of Neisseria gonorrhoeae. All of these isolates exhibited sensitivity to azithromycin and ceftriaxone, while the majority of antibiotic resistance was seen against penicillin G, sulphonamide, and ciprofloxacin. Fifty percent of the isolates exhibited absolute resistance to both sulphonamide and ciprofloxacin, whereas 40% of the isolates displayed absolute resistance to penicillin G. The antibacterial activity of P. ostreatus extracts examined in this investigation varied within the same species of microorganisms. Extract B and D, extracted in the presence of 20% wheat bran bagasse and 20% maize flour bagasse, respectively, had exceptional antibacterial activity against all target isolates examined. We observed the lowest concentration of antibacterial agent required to inhibit the target bacteria to be between 1 × 10-3 mg/ml and 1 × 10-6 mg/ml with an estimated probability of 0.30769, a lower 95% confidence interval (CI) of 0.126807, an upper 95% CI of 0.576307, an estimated probability of 0.15385, a lower 95% CI of 0.043258, and an upper 95% CI, respectively. The MBC of 1 × 10-3 mg/ml was seen to eliminate 31% of the target bacteria. This dose was the most inhibitive. The antibacterial activity of all the extracts examined in the current study exhibited some degree of efficacy against both clinical isolates and standard strains. However, the majority of clinically isolated bacteria exhibited greater resistance to the extracts.

Frontispiece: Recent advances in targeted antibacterial therapy basing on nanomaterials (EXP2 1/2023)

Nanomaterials can assist targeted bacterial depletion in either a passive or active way to enhance inhibitory activity and reduce side effects by increasing local concentration of antibacterial agents. In this review article, we summarize the recent development in the field, which will promote more innovative thinking particularly focusing on the treatment of multidrug resistant bacteria.

Electrogenerated copper selenide with positive charge to efficiently capture and combat drug-resistant bacteria for wound healing

Limited by the effective radius of metal ion release, higher concentrations of antibacterial agents are usually required to achieve satisfactory efficacy. Unfortunately, the potential cytotoxicity of metal ions limits the administered dose, which greatly hinders the widespread use of metal antibacterial agents. In this work, we used a convenient electrochemical method to prepare electropositive copper selenide (CuSe) nanosheets gathered from the cathode. Under physiological conditions, trace amounts of electrolytic CuSe (E-CuSe, 1 μg mL−1) could electrostatically bind to bacterial membranes and almost completely kill three resistant bacteria models (106 colony forming unit (CFU) mL−1). The extremely low effective dose of E-CuSe reaches a new benchmark in comparison with copper-based nanomaterials in other related studies. In addition, due to the reasonable coupling of selenium and copper, the as-prepared E-CuSe nanosheets exhibit lower cytotoxicity compared to copper oxide. As expected, the E-CuSe performed well in resistant bacteria-infected wound healing in rats, rapidly promoting wound tissue with a diameter of about 1 cm recovery within 7 days. Transcriptome analysis revealed the E-CuSe mainly acted on the membrane transport and DNA synthesis systems of bacterial cells. This work presents an efficient and in-depth paradigm for the scientific design and inactivation mechanism of metal antibacterial agents.

Characteristics of Stenotrophomonas maltophilia isolates from cystic fibrosis patients in Russia.

Stenotrophomonas maltophilia is a common opportunistic microorganism and an important respiratory pathogen in cystic fibrosis (CF). The aim of this study was to determine antimicrobial resistance phenotypes, sequence-types (ST) and genetic determinants of antibiotic resistance in S. maltophilia strains recovered from CF patients in Russia. S. maltophilia isolates recovered from 170 CF patients were analyzed. Minimum inhibitory concentrations of antibacterial agents were determined using Sensititre Gram Negative GNX2F plates and the results were interpreted according to Clinical and Laboratory Standards Institute (CLSI) criteria. Whole-genome sequencing (WGS) was performed on MGISEQ-2000 platform. SPAdes software, Galaxy, ResFinder, Integrall and PubMLST were used for analysis of WGS data. S. maltophilia strains were identified from 24/170 (14%) CF patients. In total, 25 isolates were detected, two strains were isolated from the same patient. The isolates belonged to 17 different STs, including 5 new STs; ST4 was the most prevalent ST. Resistance to ceftazidime was observed in 60% of strains, to ticarcillin-clavulanate - in 32%, to levofloxacin - in 24%, to trimethoprim/sulfamethoxazole - in 12% of strains. All isolates were susceptible to minocycline. All ST4 isolates were resistant or intermediate to ceftazidime and ticarcillin-clavulanate. In two isolates, the sul1 gene was detected. In one isolate, sul1 was part of a class 1 integron. The detected integron also contained the blaGES-7 and aac(6')-Ib-cr genes. The ST4 sequence-type was the most prevalent ST among S. maltophilia strains recovered from CF patients in Russia. Antibiotic resistance genes, including sul1, blaGES-7, aac(6')-Ib-cr, were detected in single strains.

Surface-Enhanced Raman Spectroscopy for the Characterization of the Antibacterial Properties of Imidazole Derivatives against Bacillus subtilis with Principal Component Analysis and Partial Least Squares–Discriminant Analysis

Surface enhanced Raman spectroscopy (SERS) was used to determine the biochemical changes induced during the antibacterial activity of the in house synthesized imidazole derivatives in comparison to the commercially available pharmaceutical tinidazole. The antibacterial activity was assessed against Bacillus subtilis using various concentrations of antibacterial agents for this purpose. SERS detected significant changes in the bacterial cells following the application of both drugs, confirming the potential of this approach for analyzing the antibacterial activities of drug candidates. The SERS spectral features changed consistently with the increased antibiotic concentration at 548, 713, 730, 807, 858, 951, 958, 1004, 1028, 1110, 1128, 1242, 1280, 1320, 1398, 1418, 1453, 1567, and 1590 cm−1. Principal component analysis (PCA) and partial least squares–discriminant analysis (PLS-DA) were demonstrated to be useful for comparing the antibacterial actions of these imidazole derivatives. The sensitivity and specificity of this model were 97% and 95.7% respectively.

The Effect of Various Concentrations of Ethanol Extract of the Leaves of Paederia foetida L. on the Growth of Escherichia Coli Bacteria

Bacterial infection of Escherichia coli (E. coli) as the cause of gastrointestinal disorders in humans has increased their prevalence. Treatment using natural ingredients can be a choice of therapy because of the minimal side effects. One of the rare plants believed by the community as an antibacterial is stinking vin’e known as the ‘leaf fart’. The purpose of this research is for knowing the activity of the ethanol extract of Paederia foetida L can affect the growth of E.coli. The serial diffusion disc method is being used as the antibacterial activity test. The concentration of this extract are 10%, 20%, 40%, 80%, 100% with positive control (ciprofloxacin) and negative control (aqua dest). The inhibition zone diameter characterized the effect of Extract on bacterial growth were 6.16 mm of the concentration 10%, 6.667 mm of the concentration 20%, 7.10 mm of the concentration 40 %, 7.78 mm of the concentration 80%, and 10.03 mm of the concentration 100%. As for the negative control has no effect. The study stated that the higher concentration of antibacterial agent used, the greater the inhibition zone formed. Based on the result of the analysis of the data by using the One-Way ANOVA Test showed a probability value (p) = 0.000 or value (p) < 0.05, that H0 is rejected and H1 is accepted. The conclusion is that the Extract of stinking vin’e has an antibacterial effect on the growth of E.coli.
 Keywords: Antibacterial, E.coli, Extract of Sembukan leaf

Penetration of Antibacterial Agents into Pulmonary Epithelial Lining Fluid: An Update.

A comprehensive review of drug penetration into pulmonary epithelial lining fluid (ELF) was previously published in 2011. Since then, an extensive number of studies comparing plasma and ELF concentrations of antibacterial agents have been published and are summarized in this review. The majority of the studies included in this review determined ELF concentrations of antibacterial agents using bronchoscopy and bronchoalveolar lavage, and this review focuses on intrapulmonary penetration ratios determined with area under the concentration-time curve from healthy human adult studies or pharmacokinetic modeling of various antibacterial agents. If available, pharmacokinetic/pharmacodynamic parameters determined from preclinical murine infection models that evaluated ELF concentrations are also provided. There are also a limited number of recently published investigations of intrapulmonary penetration in critically ill patients with lower respiratory tract infections, where greater variability in ELF concentrations may exist. The significance of these changes may impact the intrapulmonary penetration in the setting of infection, and further studies relating ELF concentrations to clinical response are needed. Phase I drug development programs now include assessment of initial pharmacodynamic target values for pertinent organisms in animal models, followed by evaluation of antibacterial penetration into the human lung to assist in dosage selection for clinical trials in infected patients. The recent focus has been on β-lactam agents, including those in combination with β-lactamase inhibitors, particularly due to the rise of multidrug-resistant infections. This manifests as a large portion of the review focusing on cephalosporins and carbapenems, with or without β-lactamase inhibitors, in both healthy adult subjects and critically ill patients with lower respiratory tract infections. Further studies are warranted in critically ill patients with lower respiratory tract infections to evaluate the relationship between intrapulmonary penetration and clinical and microbiological outcomes. Our clinical research experience with these studies, along with this literature review, has allowed us to outline key steps in developing and evaluating dosage regimens to treat extracellular bacteria in lower respiratory tract infections.

Inhaled antibiotics to improve efficacy and safety in the treatment of upper airway and lung inflammatory diseases

Inhaled antibacterial drugs have been used since the 1940s with greater or lesser effectiveness, due to the possibility of targeted delivery of drugs directly to the infection site at concentrations higher than MICs. High local concentrations of antibacterial agents expand the possibilities of treating infections caused by multiresistant strains and reduces antibiotic resistance in the population. The inhaled delivery method is characterized by a high level of safety due to the absence of systemic toxic effects, which reduces the risk of pseudomembranous colitis and other complications of antibiotic therapy. Thiamphenicol glycinate acetylcysteinate is a combined drug that includes thiamphenicol and N-acetylcysteine, which causes its antibacterial and mucolytic activity. The results of clinical studies have demonstrated the effectiveness of TGA in the treatment of acute and chronic bronchitis, chronic obstructive pulmonary disease, community-acquired pneumonia, laryngotracheitis, rhinosinusitis and other infections of the upper and lower respiratory tract. In pediatrics, the drug is used to treat bronchitis and pneumonia, especially those that cannot be treated with other antibacterial drugs, bronchiolitis, whooping cough, and cystic fibrosis. The article presents data on the effectiveness and safety of containing TGA. A wide spectrum of antibacterial actions, the ability to form high local concentrations of antibacterial and mucolytic components in the focus of infection, a low risk of serious side effects in both adults and children are noted. The topical use of the combination drug has proven to be effective not only in bringing about a pronounced clinical improvement, but also in reducing the frequency of use of systemic antibiotic therapy. The efficacy of thiamphenicol glycinate acetylcysteinate is not inferior to macrolide antibiotics.

Antibiofilm Efficacy of Nitric Oxide-Releasing Alginates against Cystic Fibrosis Bacterial Pathogens.

Colonization of the lungs by biofilm-forming pathogens is a major cause of mortality in cystic fibrosis (CF). In CF patients, these pathogens are difficult to treat due to the additional protection provided by both the biofilm exopolysaccharide matrix and thick, viscous mucus. The antibiofilm efficacy of nitric oxide (NO)-releasing alginates was evaluated against Pseudomonas aeruginosa, Burkholderia cepacia, Staphylococcus aureus, and methicillin-resistant S.aureus biofilms in both aerobic and anaerobic environments. Varying the amine precursor grafted onto alginate oligosaccharides imparted tunable NO storage (∼0.1-0.3 μmol/mg) and release kinetics (∼4-40 min half-lives) in the artificial sputum media used for biofilm testing. The NO-releasing alginates were highly antibacterial against the four CF-relevant pathogens, achieving a 5-log reduction in biofilm viability after 24 h of treatment, with biocidal efficacy dependent on NO-release kinetics. Aerobic biofilms required greater starting NO doses to achieve killing relative to the anaerobic biofilms. Relative to tobramycin (the minimum concentration of antibacterial agent required to achieve a 5-log reduction in viability after 24 h, MBEC24h, of ≥2000 μg/mL) and vancomycin (MBEC24h ≥ 1000 μg/mL), the NO-releasing alginates proved to be more effective (NO dose ≤ 520 μg/mL) regardless of growth conditions.

Silver nanoparticle antibacterial efficacy and resistance development in key bacterial species

Silver nanoparticles (AgNPs) are widely used for their antibacterial properties due to the expected benefit of long-term antibacterial efficacy and low potential for bacterial resistance. This study examined the potential for three bacterial species, Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii, to develop resistance to AgNPs in comparison to ciprofloxacin, benzalkonium chloride, and silver nitrate. Antibacterial efficacy was measured by determining the minimum inhibitory and minimum bactericidal concentrations using a broth microtiter method, and resistance development was tested using stepwise increasing concentrations of antibacterial agents. Only P. aeruginosa was able to develop resistance to AgNPs while all three organisms developed resistance to ciprofloxacin, and none of them developed resistance to silver nitrate or benzalkonium chloride. The resistance was stable and appeared to derive from multiple mechanisms since one AgNP-resistant variant was cross-resistant to silver nitrate, but the other variant was not. The precise mechanisms of AgNP resistance are yet to be elucidated, but they might involve the ability of phenazine pigments produced by P. aeruginosa to limit the bacterium’s exposure to silver. In order to reduce the possibility of bacteria developing resistance, AgNPs or their carrier medium should be engineered to ensure that an inhibitory concentration of silver is consistently maintained.

Bactericidal Effect of Pterostilbene Alone and in Combination with Gentamicin against Human Pathogenic Bacteria

The antibacterial activity of pterostilbene in combination with gentamicin against six strains of Gram-positive and Gram-negative bacteria were investigated. The minimum inhibitory concentration and minimum bactericidal concentration of pterostilbene were determined using microdilution technique whereas the synergistic antibacterial activities of pterostilbene in combination with gentamicin were assessed using checkerboard assay and time-kill kinetic study. Results of the present study showed that the combination effects of pterostilbene with gentamicin were synergistic (FIC index < 0.5) against three susceptible bacteria strains: Staphylococcus aureus ATCC 25923, Escherichia coli O157 and Pseudomonas aeruginosa 15442. However, the time-kill study showed that the interaction was indifference which did not significantly differ from the gentamicin treatment. Furthermore, time-kill study showed that the growth of the tested bacteria was completely attenuated with 2 to 8 h treatment with 0.5 × MIC of pterostilbene and gentamicin. The identified combinations could be of effective therapeutic value against bacterial infections. These findings have potential implications in delaying the development of bacterial resistance as the antibacterial effect was achieved with the lower concentrations of antibacterial agents.

Fabrication of Novel Antimicrobial Bio-Fibers Using Silk Wastage, Study of Poly (hexamethylene) Biguanide, and Silver Nanoparticles Interaction

ABSTRACTRegenerated silk fibers were fabricated through dry-wet spinning process using N-methyl morpholine N-oxide and methanol as solvent and coagulant, respectively. Several concentrations of poly (hexamethylene) biguanide (PHMB) (0.27, 0.41, and 0.55 mL per 1 g of fibroin) and silver nanoparticles (AgNPs) (0.0005, 0.0015, 0.0055, 0.0095, and 0.0135% (w/v) were used as antibacterial agents. Antibacterial property of bio-fibers produced by either master batch or dipping methods was compared to each other against a gram-positive bacterium, Staphylococcus aurous. Master batch process indicated the dependency of antibacterial effect on the concentration of antibacterial agents as well as particle size. Maximum bactericidal activity in this process was obtained at concentrations of 0.0055% of AgNPs and 0.55 mL of PHMB per 1 g of fibroin. However for long-lasting effect and from toxicity aspect PHMB with lower concentration (0.27 mL) and with 0.0055% AgNP was seemed to be ideal. The result from dipping process showed that various concentrations of PHMB can greatly influence on the results; the interaction of 0.0055% AgNPs and 0.41 mL of PHMB offered good antibacterial properties with the least amount of toxicity effect in human cells.

Levofloxacin hydrate 1.5 % ophthalmic solution in external ocular infections and intraocular surgery: a guide to its use

Levofloxacin hydrate 1.5 % preservative-free ophthalmic solution (Cravit®) is an effective and well-tolerated option to treat external ocular infections and to use as a perioperative aseptic in ocular surgery. Relative to other fluoroquinolones available for ophthalmic use, levofloxacin hydrate 1.5 % ophthalmic solution has the highest concentration of antibacterial agent, which results in increased concentrations of the antibacterial in tear fluid, and better ocular penetration, bactericidal activity and inhibition of resistant organisms. Levofloxacin hydrate 1.5 % ophthalmic solution provides high rates of clinical improvement and bacterial eradication in patients with bacterial conjunctivitis or bacterial keratitis, as well as high rates of bacterial eradication when used preoperatively in patients undergoing cataract surgery. The ophthalmic solution is well tolerated, with only mild adverse events being reported.

Growth and toxigenic potential of Bacillus cereus during storage temperature abuse in cooked irradiated chicken rice in combination with nisin and carvacrol

This study investigated the effect of combined treatments involving low doses of gamma irradiation in combination with nisin and carvacrol as antimicrobial agents on the growth and potential toxicity of Bacillus cereus, during storage temperature abuse. The chicken rice was spiked with endospores and was incubated at 10 °C for 2 weeks. Microbial population was examined using plate counting on MYP agar. Toxigenic potential was measured through the record of enterotoxins and phosphatidylcholine-specific phospholipase C (PC-PLC) activity. The results showed that samples processed with a combination of low irradiation dose; (D10, ½ D10) and reduced concentration of antibacterial agents (MIC, ½ MIC), resulted in a significant decrease (p ≤ 0.05) of B. cereus count compared to the samples treated only with higher amount of antimicrobial agents (2 × MIC). Toxin production was also delayed by irradiation and a total absence of enterotoxin was observed in irradiated rice at 1.8 kGy in the presence of nisin alone or in combination with carvacrol until the 12th day of storage at 10 °C. Reduced proliferation of B. cereus obtained by combined treatment was associated with a limitation of toxin production and led systematically to significant decrease (p ≤ 0.05) of PC-PLC activity during storage.

Synthesis of CuS nanoparticles and evaluation of its antimicrobial properties in combination with Linum usitatissimum root and shoot extract

AbstractHydroalcoholic extracts have been prepared from Linum usitatissimum with maceration method, which was later examined for its antimicrobial activity in the presence of CuS nanoparticles by broth macrodilution and agar disc diffusion, and the determination of minimal inhibitory concentration of antibacterial agent required to inhibit growth of a pathogen, i.e. minimal inhibitory concentration and the lowest concentration of an antibacterial agent required to kill a particular bacterium, i.e. minimal bactericidal concentration were well elucidated and evaluated for these materials. The superposition of metal nanoparticles with the L. usitatissimum extracts was found to be effective in the eradication of the bacterial infections, and proved to be a good alternative of antibiotics. Antioxidant content of the extracts was also determined and demonstrated the highest antioxidant activities associated with the shoot of L. usitatissimum (Total phenolic content 1: 128.24 ± 1.127-mg gallic acid equivalents/g...

English

Microbial resistance to antimicrobials is spreading all over the world making it difficult to treat diseases effectively. This study aims to understand the mechanism of resistance towards the antimicrobials Ceftazidime, Moxifloxacin and Nalidixic acid, by using resistant Enterobacter spp. and sensitive Enterobacter spp. While there was complete inhibition of growth of sensitive Enterobacter spp. at 8 &micro;g/ml Ceftazidime, 0.125 &micro;g/ml of&nbsp; Moxifloxacin and 16 &micro;g/ml of Nalidixic acid, resistant Enterobacter spp. even tolerated 256, 32 and 1536 &micro;g/ml Ceftazidime, Moxifloxacin and Nalidixic acid respectively. Browthdilution method was used to determine the growth of organisms at different concentrations of antibacterial agents. Mechanism of resistance was found to be present in plasmid. Absence of Beta lactamase enzyme seems to be an important finding in this sudy. B. lactamase enzyme was checked with help of the acidometric and idometric method. Plasmid isolation and analysis was done by agarose gel electrophoresis. Successful curing of plasmid was carried out with 10% sodium dodecyl sulfate (SDS). When colonies after SDS treatment were tested, resistant strains were found which were later converted to sensitive ones. In this study, the resistant Enterobacter spp. executed resistance to three different classes of antimicrobials due to the resistance plasmid. The results obtained in this study support most of the previous study findings who contributed in this field. Therefore, it might be useful to recognize the resistance mechanism, and to determine the correct practicing of drug usage. Key words: Antimicrobials, enterobacter, sensitive enterobacter, resistance mechanism, inhibition, plasmid.

Antimicrobial performance of cotton finished with triclosan, silver and chitosan

AbstractAntimicrobial agents are applied on textiles to suppress growth of microorganism, odour generation as well as its deterioration. Cotton fabric was finished with three different types of antimicrobial agents (1) Ultrafresh NMV2: a triclosan based product, (2) N9 Pure silver: a dispersion of pure silver metal, and (3) chitosan to develop antimicrobial characteristics. Finished fabrics were evaluated for their effectiveness against Gram positive bacterium (Staphylococcus aureus) and Gram negative bacterium (Escherichia coli) in terms of percentage reduction in CFU of bacteria. The influence of finishing methods, via. pad-dry and pad-dry-cure followed by repeated launderings, concentrations of antibacterial agents, and pH were optimised. The antimicrobial performance was evaluated prior to laundering and after each five laundering cycles; results were statistically analysed and effects on physical properties of the finished fabric were also evaluated. Triclosan was found to be significantly effective at low concentrations, whereas silver showed remarkably good antimicrobial activity at or above 10 g/L and chitosan was comparably less active compared to others. Cyclic laundering showed statistically significant effect on activity of finishes up to five cycles but it was almost reduced to half for chitosan.

Study on antibacterial property of silver loaded titanium dioxide antibacterial coated endotracheal intubation tube

To study the antibacterial property of silver loaded titanium dioxide (TiO2) antibacterial coated endotracheal intubation tube, and to determine the minimum effective antibacterial concentration. Intubation tubes coated with different concentrations of antibacterial agents were prepared with sol gel method. Polyethylene endotracheal intubation tubes were used as substrate, and silver loaded TiO2 was used as the antibacterial agent. According to the different antibacterial concentrations of the antibacterial agent, the tubes were divided into nine groups: 10.0% group, 5.0% group, 2.0% group, 1.5% group, 1.0% group, 0.8% group, 0.6% group, 0.2% group, and control group. They were respectively immersed in three standard bacteria suspensions with 1.0×10(5) cfu/mL: Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli. Together with standard bacteria liquid group, there were 10 experimental groups. They were kept overnight for 24 hours. 10 μL of respective culture medium was smeared on blood agar culture medium. After being cultured overnight in 35 centigrade, the number of bacteria colonies was respectively counted. In 1.0×10(5) cfu/mL of three standard bacteria liquids with antibacterial agent concentration ≥1.0%, three bacterial colonies had un-obviously growth rate. Almost the same strong antibacterial effects to achieve sterilizing rates of more than 98% was shown in each group of the antibacterial coating endotracheal intubation tubes (all P>0.05). As the antibacterial agent concentration decreased, three bacterial colonies were increasing gradually. Intermediate antibacterial effects were shown in tubes of 0.8% group, with significant statistic difference as compared with 1.0% and 0.6% groups [Pseudomonas aeruginosa: 7.300 (4.050, 8.350) vs. 0.200 (0.050, 1.200), 9.700(9.000, 10.000); Staphylococcus aureus: 4.100 (3.300, 4.650) vs. 0.000 (0.000, 0.150), 5.800 (5.350, 7.650); Escherichia coli: 1.400 (0.750, 3.750) vs. 0.050 (0.025, 0.050), 9.500 (8.500, 9.800), all P<0.01]. Silver loaded TiO2 antibacterial coated endotracheal intubation tube had definite antibacterial properties, which were related to the antibacterial concentration. Strong antibacterial effects were shown when antibacterial concentration was above 1.0%, with bacteria almost completely killed in the immersing liquid.

Assessment of drug hypersensitivity with non-irritating concentrations of antibacterial agents for allergic skin tests: a review

Hypersensitivity reactions to antibiotics are common with a prevalence of 6-10% of all adverse reactions. There is a lack of guidelines and standardization of skin tests for the screening of hypersensitivity to all antibiotics, in terms of the methodology, dose and time of evaluation of the tests. Literature from Europe and America suggests the use of non-irritating concentration (NIC) of antibiotics for skin testing such as intra dermal test (IDT), skin prick test (SPT). These are concentrations at which the drug is unlikely to produce irritation by virtue of its chemical nature resulting in false positive reactions. These concentrations have been validated by trials in their populations. Due to the increase of antibiotic resistance in our country, declaring a patient allergic to a specific class of antibiotics based on positive skin tests can further narrow the therapeutic armory. These individuals have an increased incidence of infections with resistant organisms as well as increased cost of hospitalization. This is due to the use of alternative broad spectrum antibiotics. Therefore, there is a need for a standardized protocol for the use of skin tests in screening of hypersensitivity, with validated NIC of all antibacterial agents. The aim of this article is to review literature of protocols for assessment of drug hypersensitivity with NIC of antibacterial drugs for SPT, IDT and also establish the need for research in this area in our country.

Study on the Antibacterial Performance of the Antibacterial Shutter Blades

This study used Ag-embedded nanoTiO2, xylan and water-soluble Chitosan as antibacterial agents, respectively prepared shutter blades through the treating solution of the different concentration and the different drug loading amount of the poplar veneer. Through a single factor experiment, this paper analyzes that the different antibacterial agent, concentration of antibacterial agent and the drug loading amount have an effect on the antibacterial properties of the shutter blades. The results show that the order of antibacterial performance of the shutter blades impregnated antibacterial agents is the Ag-embedded nanoTiO2, Chitosan, Xylan. Comprehensiv-ely thought the antibacterial properties and economic index, the optimal concentration of the Ag-embedded nanoTiO2 impregnation solution is 1%.