金葡菌疫苗的研究进展

金葡菌(Staphylococcus aureus,SA)是人体感染的常见病原菌,随着抗菌素的广泛使用,其耐药性也日趋严重,临床用药面临着严峻的挑战。20世纪60年代以来,人们不断尝试各种防治SA感染的免疫手段,到目前为止,虽尚未发现一种行之有效的免疫手段应用于临床,但在探索过程中,人们发现,免疫预防与治疗具有广阔的应用前景。本文对近年来SA疫苗的研究进展作一综述。     

Microbial contamination of orthodontic buccal tubes from manufacturers

This study aimed to test the sterility of new unused orthodontic buccal tubes received from manufacturers. Four different types of buccal tubes were used straight from the manufactures package without any additional sterilizing step. Of these buccal tubes tested, three genera of bacteria, implicated as opportunistic pathogens, namely Micrococcus luteus, Staphylococcus haemolyticus and Acinetobacter calcoaceticus were recovered from these buccal tubes. Our data showing microbial contamination on buccal tubes highlights the need of sterilization before clinical use. We also suggest that manufacturers should list the sterility state of orthodontic buccal tubes on their packaging or instructions stating the need for sterilization.     

Inhibition of Bacterial Dihydrofolate Reductase by 6‐Alkyl‐2,4‐diaminopyrimidines

(±)‐6‐Alkyl‐2,4‐diaminopyrimidine‐based inhibitors of bacterial dihydrofolate reductase (DHFR) have been prepared and evaluated for biological potency against Bacillus anthracis and Staphylococcus aureus. Biological studies revealed attenuated activity relative to earlier structures lacking substitution at C6 of the diaminopyrimidine moiety, though minimum inhibitory concentration (MIC) values are in the 0.125–8 μg mL^?1 range for both organisms. This effect was rationalized from three‐ dimensional X‐ray structure studies that indicate the presence of a side pocket containing two water molecules adjacent to the main binding pocket. Because of the hydrophobic nature of the substitutions at C6, the main interactions are with protein residues Leu 20 and Leu 28. These interactions lead to a minor conformational change in the protein, which opens the pocket containing these water molecules such that it becomes continuous with the main binding pocket. These water molecules are reported to play a critical role in the catalytic reaction, highlighting a new area for inhibitor expansion within the limited architectural variation at the catalytic site of bacterial DHFR.     

Improvement of the pore trapping method to immobilize vital coccoid bacteria for high‐resolution AFM: a study of Staphylococcus aureus

Preparation of vital bacteria for atomic force microscope study under aqueous fluid, such as physiological buffer or bacterial growth medium, presents challenges as cells will often desorb from the supporting surface or be dislodged by the atomic force microscope tip during imaging. An established method of immobilizing coccoid bacteria is to trap cells in polycarbonate track etched filter pores. We have significantly improved this method by modifying the pore diameter of commercially available filters to correspond to the diameter of the target strain, enabling high‐resolution imaging of stationary organisms under buffer and dividing organisms under growth media.     

Analysis of antibiotic resistance patterns and detection of mecA gene in Staphylococcus aureus isolated from packaged hamburger

Presence of Staphylococcus aureus, antibiotic resistance pattern and PCR detection of mecA gene in isolated strains were investigated in total of 256 packaged hamburgers in Iran-Tehran. For this purpose we used standard disk-diffusion method and sensitive and specific PCR technique, respectively. Results showed that 25% of samples were positive for S. aureus. Resistance to meticillin, erythromycin, penicillin G, cefazolin, ciprofloxasin, vacomycin and amoxiclave was determined 89%, 20.3%, 18.7%, 15.6%, 14%, 26.6% and 12.5%, respectively. According to the obtained results from PCR analysis of methicillin-resistant S. aureus (MRSA), mecA gene was present in 100% of the resistant isolates, 0% of intermediate-resistance isolates and 25% of susceptible isolates. The results obtained from PCR detection of mecA gene showed high correlation with standard disk diffusion test.     

Mechanism of the combined anti-bacterial effect of green tea extract and NaCl against Staphylococcus aureus and Escherichia coli O157:H7

The mechanism of the combined anti-bacterial effect of green tea extract (GTE) and NaCl against Staphylococcus aureus NBRC 13276 and Escherichia coli O157:H7 was investigated. After treatment for 1 h, GTE was more effective against S. aureus than E. coli O157:H7, and combined GTE/NaCl treatment caused greater cellular damage in S. aureus NBRC 13276, where it was bactericidal, than E. coli O157:H7. Compared to treatment with 1.0 mg/mL GTE, which had no effect on the survival rate of E. coli O157:H7 after 48 h, treatment with 4% NaCl alone caused greater cellular damage. Moreover, bacteria pretreated with NaCl showed delayed growth in the presence of GTE. It is therefore likely that susceptibility of E. coli O157:H7 to GTE was increased by exposure to NaCl. E. coli O157:H7 pretreated with GTE and NaCl did not multiply in the presence of GTE. Visualization of the catechin components of GTE-treated bacteria using an electron microscope and SDS-PAGE analysis of cell proteins showed that GTE attached to proteins on the surface of the bacteria to form high-molecular weight complexes, suggesting the possibility that GTE inhibits the uptake and secretion of substrates and inhibits enzyme activity. Notably, after the GTE treatment for 1 h, both bacterial strains suffered injury but recovered by cultivation in rich medium. The damage and aggregation of proteins caused by GTE treatment were repaired upon treatment with LP diluent.     

发酵玉米醪中细菌数量变化及抑菌作用研究

研究了15、20、25、30和35℃温度下自然发酵的玉米醪中乳酸菌与菌落总教的变化以及发酵玉米醪的抑菌作用.结果表明,不同发酵温度下乳酸菌总数初始范围5.70 lg～7.76lg,各温度间乳酸菌总数存在显著性差异(P＜0.05),最大值范围8.93 lg～9.33 lg;菌落总数初始范围5.70 lg～7.74lg,最大值范围8.77 lg～9.18 lg,乳酸菌总数及菌落总数之间均存在极显著正相关关系(P=0.000),表明发酵玉米醪中乳酸菌为优势菌.发酵玉米醪对金黄色葡萄球菌(Staphyloccocus aureus sp.)和大肠杆菌(Escherichia coli sp.)没有抑制作用,而发酵48 h的玉米醪上清液对两种菌均产生抑制作用,且发酵72 h的玉米醪上清液的抑菌作用比48 h时显著提高(P＜0.05).相同发酵阶段的玉米醪上清波对两种待测菌的抑制作用没有显著性差异(P＞0.05).     

抑制萝卜干中表皮葡萄球菌和短乳杆菌的研究

为了解决真空包装萝卜干胖袋问题.使用多种抑菌剂对从胖袋的真空包装的萧山萝卜干中分离出来的产气的表皮葡萄球菌和短乳杆菌生长进行抑制实验.试验发现,3‰的富马酸对两种菌抑制效果最好,0.25‰的尼泊金混合酯(用5‰乙醇溶解)也很有好的抑制该两种菌的作用.并发现作为尼泊金混合酯溶剂的5‰的乙醇,单独使用竟然也有比较好的抑制作...     

Combinatorial materials research applied to the development of new surface coatings XII: Novel, environmentally friendly antimicrobial coatings derived from biocide-functional acrylic polyols and isocyanates

Novel, environmentally friendly antimicrobial coatings containing tethered biocide moieties derived from the ubiquitous biocide, triclosan, were synthesized and characterized using a high-throughput workflow. Triclosan was first modified with an acrylate functionality and, subsequently, copolymerized with hydroxyethyl acrylate and butyl acrylate using conventional free radical polymerization to form an array of acrylic polyol terpolymers. The polyols were characterized using nuclear magnetic resonance spectroscopy, differential scanning calorimetry, and gel permeation chromatography. Arrays of urethane coatings were produced from the array of acrylic polyol terpolymers and, subsequently, characterized using parallel dynamic mechanical thermal analysis, surface energy measurements, and various biological assays. The results of the biological assays showed that the coatings were effective toward inhibiting Staphylococcus epidermidis biofilm retention without leaching triclosan or other toxic components from the coating. The level of antimicrobial activity was found to increase with the content of triclosan moieties incorporated into the coating matrix. These results indicate that triclosan moieties tethered to a polymer matrix can impart antimicrobial properties via a contact-active, nonleaching (i.e., environmentally friendly) mechanism. Since S. epidermidis is one of the primary microorganisms associated with infection and failure of implanted medical devices, such as prosthetic heart valves, urinary catheters, and a variety of orthopedic implants, these coatings may have good potential for commercialization in some of these applications. This paper was awarded First Place in the 2008 Roon Awards competition, held as part of the FutureCoat! conference, sponsored by the Federation of Societies for Coatings Technology, in Chicago, IL, on October 14–16, 2008.