2001～2003年社区呼吸道感染病原菌耐药动态

目的 调查头孢克洛及其他 5种抗生素对社区获得呼吸道感染病原菌体外抗菌活性。方法 多中心收集菌株 ,集中复检菌种和检测细菌对 6种抗生素的 MIC值 ;菌种复检采用自动细菌鉴定系统 VITED- cc4的 GPI或NHI卡或特异单克隆乳胶试剂 ;Etest方法测试菌株 MIC值。结果 共检测 6 11株菌 ,其中 30 9株流感嗜血菌、12 0株肺炎链球菌、6 1株粘膜炎莫拉菌、6 1株敏感的金黄色葡萄球菌和 6 0株 β-溶血性链球菌 ;2 0 0 3年监测结果表明 :35 .8%耐青霉素肺炎链球菌 ,高耐株由 2 0 0 1～ 2 0 0 2年的 8%上升至 10 % ;耐氨苄西林流感嗜血菌为 9.4 % ,阿奇霉素对肺炎链球菌、β-溶血性链球菌和金黄色葡萄球菌的耐药率分别由 2 0 0 1～ 2 0 0 2年的 74 .2 %、6 3.2 %和33.3%上升至 82 .5 %、88.3%和 5 7.4 %。结论 2 0 0 3年社区呼吸道感染主要病原菌对常用抗生素的耐药率有不同程度的上升 ;头孢克洛对所检测的病原菌均有良好的抗菌活性 ,可作为社区中轻度呼吸道感染经验治疗的首选药物。

细菌耐药动态监测及预警

目的:动态监测我院细菌的耐药情况,及时预警。方法:检测6 720份送检标本的细菌种类及药物敏感情况。结果:我院感染性疾病主要以革兰阴性菌为主,克雷伯菌和大肠埃希菌为最常见的临床分离细菌。结论:定期监测细菌耐药,动态预警,对控制医院感染、减少耐药菌产生有重要意义。

庆大霉素动态耐药高产菌种的选育方法

用庆大霉素炭脱液动态处理庆大霉素棘孢小单孢菌 ,使庆大霉素菌种平均发酵单位提高 30 0U/ml,可以直接制备庆大霉素高产菌种。对提高抗生素的发酵水平有显著效果。

肺结核患者T细胞及相关细胞因子动态变化的研究进展

【目的】机体免疫功能状态是肺结核发病的主要诱因之一,T细胞、相关细胞因子在结核病中的存在量异常与机体免疫状态有关,动态观察T细胞及炎性因子的变化,对进一步研究结核发病机制、控制和预防耐药肺结核的发生、发展具有重要意义。对此,本文通过对国内外T细胞、相关细胞因子在肺结核中的动态变化及临床价值进行综述,了解这方面的研究前沿,从而为耐药肺结核T细胞及相关细胞因子的下一步研究奠定一定的理论基础。

Dynamic changes and surveillance function of prion protein expression in gastric cancer drug resistance

AIM:To explore the dynamic changes of prion protein (PrPc) in the process of gastric cancer drug resistance and the role of PrPc expression in the prognosis of gastric cancer patients receiving chemotherapy.METHODS:A series of gastric cancer cell lines resistant to different concentrations of adriamycin was established,and the expression of PrPc,Bcl-2 and Bax was detected in these cells.Apoptosis was determined using Annexin V staining.Western blotting and immunohisto-chemistry were performed to detect the expression of PrPc in patients receiving chemotherapy and to explore the role of PrPc expression in predicting the chemosensitivity and the outcome of gastric cancer patients receiving chemotherapy.Follow-up was performed for 2 years.RESULTS:PrPc expression was increased with the increase in drug resistance.Bcl-2,together with PrPc,increased the level of anti-apoptosis of cancer cells.Increased PrPc expression predicted the enhanced level of anti-apoptosis and resistance to anticancer drugs.PrPc expression could be used as a marker for predicting the efficacy of chemotherapy and the prognosis of gastric cancer.Increased PrPc expression predicted both poor chemosensitivity and a low 2-year survival rate.Contrarily,low PrPc expression predicted favorable chemosensitivity and a relatively high 2-year survival rate.CONCLUSION:PrPc expression is associated with histological types and differentiation of gastric cancer cells;The PrPc expression level might be a valuable marker in predicting the efficacy of chemotherapy and the prognosis of gastric cancer patients receiving chemotherapy.

EBS-Based Collusion Resistant Group Key Management Using Attribute-Based Enc ryption

The m ajor advantages of EBS-based key rrkanagerrent scheme are its enhanced network survivability, high dynamic performance, and better support for network expansion. But it suffers from the collusion problem, which means it is prone to the cooperative attack of evicted members. A novel EBS-based collusion resistant group management scheme utilizing the construction of Ciphertext-Policy Attribute-Based Encryption （CP-ABE） is proposed. The new scheme satisfies the desired security properties, such as forward secrecy, backward secrecy and collusion secrecy. Compared with existing EBS-based key rmnagement scheme, the new scheme can resolve EBS collusion problem completely. Even all evicted members work together, and share their individual piece of information, they could not access to the new group key. In addition, our scheme is more efficient in terms of conmnication and computation overhead when the group size is large. It can be well controlled even in the case of large-scale application scenarios.

Accurate assessment of antibiotic susceptibility and screening resistant strains of a bacterial population by linear gradient plate

The dynamics of a bacterial population exposed to the minimum inhibitory concentration （MIC） of an antibiotic is an important issue in pharmacological research. Therefore, a novel antibiotic susceptibility test is urgently needed that can both precisely determine the MIC and accurately select antibiotic-resistant strains from clinical bacterial populations. For this purpose, we developed a method based on Fick＇s laws of diffusion using agar plates containing a linear gradient of antibiotic. The gradient plate contained two layers. The bottom layer consisted of 15 mL agar containing the appropriate concentration of enrofloxacin and allowed to harden in the form of a wedge with the plate slanted such that the entire bottom was just covered. The upper layer consisted of 15 mL plain nutrient agar added with the plate held in the horizontal position. After allowing vertical diffusion of the drug from the bottom agar layer for 12 h, the enrofloxacin concentration was diluted in proportion to the ratio of the agar layer thicknesses. The uniform linear concentration gradient was verified by measuring the enrofloxacin concentration on the agar surface. When heavy bacterial suspensions were spread on the agar surface and incubated for more than 12 h, only resistant cells were able to form colonies beyond the boundary of confluent growth of susceptible cells. In this way, the true MIC of enrofloxacin was determined. The MICs obtained using this linear gradient plate were consistent with those obtained using conventional antibiotic susceptibility tests. Discrete colonies were then spread onto a gradient plate with higher antibiotic concentrations; the boundary line increased significantly, and gene mutations conferring resistance were identified. This new method enables the rapid identification of resistant strains in the bacterial population. Use of the linear gradient plate can easily identify the precise MIC and reveal the dynamic differentiation of bacteria near the MIC. This method allows the study of genetic and physiological characteristics of individual strains, and may be useful for early warning of antibiotic resistance that may occur after use of certain antirnicrobial agents, and guide clinical treatment.