Synthetic lipopeptides: a novel class of anti-infectives

Lipopeptide daptomycin is one of the few recently approved antibiotics based on the novel mechanism of action. Recent advances in synthetic lipopeptides, driven by the biochemical and biophysical research, expanded their spectrum of antimicrobial activity and reduced their size to achieve economically viable production. Lipopeptides, consisting of a short peptide chain conjugated with an acyl chain, form a structurally defined conformation, which inserts into the bacterial membrane and dissipates its transmembrane potential. In addition to antimicrobial activity, synthetic lipopeptides also suppress inflammation through the neutralization of bacterial agonists of the innate immune response, synergize with conventional antibiotics and have improved proteolytic stability. Activities in animal models indicate that synthetic lipopeptides may surpass the natural lipopeptides as the perspective class of anti-infective agents.     

Contamination of Herbal Medicinal Products Marketed in Kaduna Metropolis with Selected Pathogenic Bacteria

The study aimed to evaluate the bacterial contamination of powdered herbal medicinal preparations sourced from identified herbal retail outlets in different parts of Kaduna metropolis. The assessments of the contamination of the herbal products were carried out using standard procedures: total aerobic bacterial plate count, measurement of some physical parameters, isolation and characterization of selected bacterial pathogens etc. The results showed that out of a total of 150, 70 (46.67%) herbal remedies were contaminated with Salmonella typhi, twenty nine (19.33%) with Shigella spp. Eighty eight (58.67%) and 98 (65.33%) were contaminated with Escherichia coli and Staphylococcus aureus, respectively. The total aerobic plate count results showed that the highest average count of > 5×10⁷cfu/g was found in 89 (59.33%) of the preparations, while average plate count of ≤5×10⁷cfu/g was found in 42 (28%) and no bacterial count was obtained in 19 (12.67%) of the preparations. Correlation was positive (P = 0.01; r = +0.109) between the physical parameters tested and the bacterial load. Antibacterial activities result of some common antibiotics showed that all the antibiotics had activities on the test bacterial isolates at various minimum inhibitory concentrations. Most traditionally prepared herbal medications in Kaduna state are likely to be contaminated with a wide variety of potentially pathogenic bacteria. The quality assurance of these products should be thoroughly enforced and monitored in the production and distribution of herbal preparations.     

烧伤病人早期肠源性感染临床研究

目的 探讨临床烧伤早期肠源性感染的发生率。方法 对１５０例烧伤面积在３５％￣９５％的病人，按烧伤至入院时间分伤后４ｈ内、４￣８ｈ、８ｈ以上３个时相组，在入院即刻抽血培养检查。结果 伤后３个时相组血培养检查无１例阳性结果发现。结论 临床烧伤病人早期肠道细菌移位的发生率远没有实验研究那么高，就其原因进行了分析。     

邦达治疗细菌感染性疾病的对照研究

目的观察邦达(哌拉西林/他唑巴坦)的临床疗效及安全性.方法将符合入选条件的患者164例,随机分为试验组与对照组各82例.试验组给予邦达4.0g/d,对照组给予舒普深3.0g/d,分别加入100ml的生理盐水中静脉滴注,30～60min滴完,每隔8h1次,疗程均为7～14d.结果试验组有效率为92.7%,细菌清除率为94.4%,不良反应发生率为3.7%;对照组有效率为90.2%,细菌清除率为90.9%,不良反应发生率为4.9%.结论邦达用于治疗多种细菌感染性疾病,特别是产酶菌引起的感染,临床疗效确切且不良反应轻微,是一种安全高效的抗菌药物.     

Use of dithiothreitol to improve the diagnosis of prosthetic joint infections

Diagnosis of prosthetic joint infections (PJIs) remains a challenge for microbiologists, despite new techniques for bacteria isolation have been developed in recent years. A widely recognized standard method has not yet been indicated mainly because of limitations due difficult procedures and need of dedicated instrumentation. We evaluated the ability of a sulfhydryl compound routinely used in microbiology laboratories, dithiothreitol (DTT), to dislodge bacteria from biofilm, keeping them alive and cultivable for identification and antibiotic susceptibility testing. We compared DTT treatment against sonication of prosthesis and culture of periprosthetic tissues, in order to establish if it could be introduced in routine microbiological diagnosis of PJIs. The study was conducted on 76 patients, 34 with aseptic loosening of their prosthesis and 42 who were diagnosed for PJI. DTT treatment gave results similar to sonication in terms of bacterial yielding. Sonication provided higher sensitivity (71.4%) and specificity (94.1%) respect to periprosthetic tissue culture, while DTT showed the same specificity of sonication but a better sensitivity (85.7%), especially when the causative microorganism was Staphylococcus epidermidis. In conclusion, we demonstrated that DTT could be used for PJIs diagnosis, thanks to its ease of use and its high sensitivity and specificity. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1694–1699, 2013     

糖尿病合并尿路感染97例尿细菌培养及药敏试验分析

目的 探讨糖尿病合并尿路感染尿细菌培养及药敏试验情况,为临床合理用药提供依据.方法 对2008年7月～2010年6月97例糖尿病合并尿路感染患者的清洁中段尿进行细菌分离培养及药敏试验.结果 患者尿液革兰阴性杆菌阳性率为72.4%,其中大肠埃氏菌的阳性率为61.2%;革兰阳性球菌阳性率为22.5%,其中肠球菌的阳性率...     

Do bacterial cellulose membranes have potential in drug-delivery systems?

Introduction: Bacterial cellulose (BC) is an extremely pure form of cellulose, which, due to its unique properties, such as high purity, water-holding capacity, three-dimensional nanofibrilar network, mechanical strength, biodegradability and biocompatibility, shows a high potential as nanomaterial in a wide range of high-tech domains including biomedical applications, and most notably in controlled drug-delivery systems.

Areas covered: This appraisal is intended to cover the major characteristics of BC, followed by the key aspects of BC production both in static and agitated conditions, and a glance of the major applications of BC, giving some emphasis to biomedical applications. Finally, a detailed discussion of the different applications of BC in controlled drug-delivery systems will be put forward, with focus on topical and oral drug-delivery systems, using either native BC or composite materials thereof.

Expert opinion: The limited number of studies carried out so far demonstrated that BC, or materials prepared from it, are interesting materials for drug-delivery systems. There is, however, a large field of systematic research ahead to develop new and more selectively responsive materials and eventually to conjugate them with other biomedical applications of BC under development.     

Bacterial translation elongation factor EF-Tu interacts and colocalizes with actin-like MreB protein

We show that translation initiation factor EF-Tu plays a second important role in cell shape maintenance in the bacterium Bacillus subtilis. EF-Tu localizes in a helical pattern underneath the cell membrane and colocalizes with MreB, an actin-like cytoskeletal element setting up rod cell shape. The localization of MreB and of EF-Tu is interdependent, but in contrast to the dynamic MreB filaments, EF-Tu structures are more static and may serve as tracks for MreB filaments. In agreement with this idea, EF-Tu and MreB interact in vivo and in vitro. Lowering of the EF-Tu levels had a minor effect on translation but a strong effect on cell shape and on the localization of MreB, and blocking of the function of EF-Tu in translation did not interfere with the localization of MreB, showing that, directly or indirectly, EF-Tu affects the cytoskeletal MreB structure and thus serves two important functions in a bacterium.     

Nitrate and bacterial contamination in well waters in Vinh Phuc province, Vietnam

Measurements were made of the nitrate concentration and bacterial contamination of groundwater samples taken from both dug wells and bores in the commune of Hop Thinh', in the administrative district of Vinh Phuc, Vietnam. A significant number (18%) of samples had nitrate concentrations in excess of the WHO Guideline value for drinking water of 50 mg L^-1, with a higher proportion in the dug wells (29%) than the bores (3.8%). High concentrations of thermotolerant coliforms were found in many of the dug wells and even in the deeper drilled bores. At the time of the study no Shigella or other infectious organisms were found. There was no correlation between nitrate concentration and bacterial content and it is concluded that nitrate concentration is not a good indicator for bacterial contamination.