产抑菌活性物质放线菌菌株的筛选

[目的]筛选产抑菌活性物质的放线菌菌株.[方法]以金黄色葡萄球菌、对青霉素和头孢菌素类耐药的金黄色葡萄球菌和大肠杆菌作为指示菌,采用滤纸片扩散法对300株放线菌的发酵产物进行抗菌活性筛选,通过最小抑菌浓度法(MIC)时筛选的阳性菌株进行抗菌活性测定.[结果]筛选到抗菌活性物质产生菌111株,抑菌率为37.0%;其中对金黄色葡萄球菌、大肠杆菌和耐药金黄色葡萄球菌有抑制活性的菌株分别为111、10和47株.各菌株的最小抑菌浓度有很大差别,菌株174883对金黄色葡萄球菌的抑菌活性最强,其发酵样品稀释到2048倍仍然表现出抑菌活性.用青霉素酶和头孢菌素酶作用于阳性菌株发酵产物,筛选到6株菌株代谢产物的抑菌活性变弱,菌株32349和kj0428的抑菌活性被抑制最明显.[结论]筛选得到的阳性放线菌菌株具有良好的抗菌活性,为新型抗生素的筛选提供了研究基础.     

桃根癌病菌拮抗放线菌抑菌活性物质的分离及其初步鉴定

[目的]分离并初步鉴定从桃树高发根癌病土壤中获得的拮抗线菌G19菌株的抑菌活性物质.[方法]采用蛋白沉淀法对拮抗放线菌G19菌株的抑菌活性物质进行粗提,利用高效液相色谱仪、中压制备色谱仪对其进行分离、纯化,应用MALDI-TOFMS法进行分子量的测定,最后通过化学显色反应进行相关官能团的验证.[结果]经分离纯化后拮抗放线菌G19的抑菌物质被抨击出7个肽段,是分子量范围为900～1 300 Da,同时推断其含有一个Cys并携带H<,2>O,Na<'+>;官能团显色反应验证该物质为多肽且含有糖基.[结论]研究结果为拮抗放线菌G19菌株的抑菌物质结构的最终确定奠定了基础.     

泡菜中乳酸菌的分离及其发酵液抑菌活性研究

[目的]从泡菜中分离筛选优势乳酸菌并时其产抑菌物质进行研究,为生产纯菌乳酸茵发酵剂、改进传统乳酸发酵食品生产提供参考.[方法]利用乳酸菌分离培养基从泡菜中分离产酸菌,并通过产酸试验、形态学及生化特性判断是否为乳酸菌属;取发酵上清液进行抑菌活性研究.[结果]从泡菜中分离获得11株产酸菌,产酸试验表明J-4、J-5、J-9、J-11为优势产酸菌;通过形态学及生化特性,初步鉴定4株产酸菌均为乳酸杆菌属;发酵上清液抑菌试验表明,4株菌均具有较强的抑菌活性,其中,J-4还具有广谱抑菌活性.[结论]研究对于纯种发酵及乳酸菌抑菌素的开发应用具有一定的启发和借鉴价值.     

狼爪瓦松全草粗提物体外抑菌作用研究

[目的]研究狼爪瓦松(Orostachys cartilaginous A.Bor)全草粗提取物体外抑菌作用.[方法]采用液-液萃取法对狼爪瓦松的体积分数为0.75的丙酮提取液的活性成分进行初步分离,制备氯仿、乙酸乙酯、正丁醇及水相萃取物.采用滤纸片法和2倍连续稀释法测定了各相萃取物对4种供试菌的体外抑菌效果.[结果]狼爪瓦松全草体积分数为0.75的丙酮提取液的各萃取相对金黄色葡萄球菌、枯草芽孢杆菌、大肠杆菌和普通变形杆菌有不同程度的抑菌活性,其中氯仿萃取相、乙酸乙酯萃取相对金黄色葡萄球菌显示了较好的抑菌效果,最低抑菌浓度均为1.25 mg/ml.[结论]中药狼爪瓦松全草的抑菌活性成分主要存在于氯仿萃取相和乙酸乙酯萃取相中,为狼爪瓦松抑菌药物的开发提供了理论依据.     

曼陀罗内生真菌代谢产物抗皮肤致病真菌活性成分研究

[目的]研究曼陀罗植物内生真菌Ym311977菌株代谢产物的抑菌活性及其有效成份.[方法]对Ym311977菌株进行扩大发酵培养,从发酵产物中分离单体化合物,并研究单体化合物对2株皮肤致病真菌的体外抑制活性.[结果]分离到的4种单体化合物中的1种对2株皮肤致病真菌(石膏样小孢子菌、石膏样毛癣菌)的最低抑菌浓度分别为50、200μg/ml;该化合物经'HNMR及13CNMR分析,确定其结构为5-丁基吡啶甲酸,即镰刀菌酸.[结论]该研究首次报道了曼陀罗内生真菌代谢产物镰刀菌酸对2株皮肤致病真菌具有押制活性.     

豹斑毒鹅膏菌毒素粗品对黄粉虫的毒性研究

[目的]探讨豹斑毒鹅膏菌毒素粗品对黄粉虫的毒性.[方法]测定了5种大型真菌子实体及毒素粗品对黄粉虫的毒杀活性,并对筛选出的豹斑毒鹅膏菌进行了致死效应研究.[结果]随着豹斑毒鹅膏菌毒素粗品浓度的增大,防治效果越来越明显.当豹斑毒鹅膏菌毒素粗品浓度为17.5 mg/ml时,黄粉虫死亡率为93.3%,效果显著.[结论]豹斑毒鹅膏菌毒素粗品对黄粉虫有较显著的毒杀作用.     

大叶胡颓子叶乙酸乙酯部抗菌作用的研究

[目的]研究大叶胡颓子叶乙酸乙酯部的抑菌作用.[方法]大叶胡颓子叶经乙醇提取,石油醚、氯仿、乙酸乙酯依次萃取,采用滤纸片法和平板法对乙酸乙酯部进行体外抑菌作用研究.[结果]大叶胡颓子叶乙酸乙酯部对5种常见的呼吸道感染菌(金黄色葡萄球菌、大肠杆菌、铜绿假单胞菌、肺炎克氏杆菌、鲍曼不动杆菌)均有较强的体外抑制作用,最小抑菌浓度为0.357～1.429 mg/ml.[结论]乙酸乙酯部为大叶胡颓子叶抗菌的活性部位,是寻找新抑菌活性成分的基础,可用于研发抗菌消炎新药物.     

臭牡丹提取物对病原真菌抑菌效果的研究

[目的]研究臭牡丹不同部位的不同溶剂提取物对常见植物病原真菌的抑制效果.[方法]采用菌饼法研究臭牡丹的抑菌能力.[结果]臭牡丹提取物对小麦赤霉、杨树溃疡、棉花枯萎、番茄灰霉病菌均具有不同程度的抑制作用,其中,茎的蒸馏水提取物对杨树溃疡病菌的抑制效果最好,其最小抑菌浓度(M/C)为15mg/ml;茎的80%乙醇提取物对小麦赤霉病菌的抑制效果最好,其MIC为30mg/ml.臭牡丹提取物在pH4～8的范围内具有不同程度的抑菌作用.[结论]臭牡丹提取物对4种病原真菌具有较好的抑制效果.     

不同中微量元素对黄瓜黑星病菌的抑制作用及其对酶活性的影响

[目的]探索中微量元素对黄瓜黑星病的防治效果及其对黄瓜植株酶活性的影响.[方法]通过室内抑菌试验及盆栽试验,研究不同中微量元素对黄瓜黑星病的防治效果;同时检测喷施中微量元素化合物后7 d黄瓜苗期叶片的可溶性蛋白、丙二醛含量, 及过氧化物酶(POD)和超氧化物歧化酶(SOD)的活性.[结果]3种微量元素对黑星病菌均有一定抑制作用,以氯化钙处理效果最为显著, 防效达到66.9%;硼酸和硫酸锌处理的防效分别为54.6%和24.1%.黄瓜植株遭受黑星痛原菌侵害后,几种不同中微量元素的施用均能有效降低黄瓜叶片中MDA含量,锌和硼处理能显著提高黄瓜植株体内蛋白质含量,锌和钙处理均可诱导黄瓜植株中POD和SOD活性上升,从而通过减缓细胞膜质的受损程度来提高黄瓜植株对黑星病菌的抵抗能力.[结论]该研究结果为中微量元素防治黄瓜黑星痛的实际应用及其抗病机理研究提供了理论基础.     

6种植物提取物的抑菌活性研究

[目的]研究大蒜、石榴、苍耳等6种植物提取物时几种常见蔬菜病害病原菌的抑制作用.[方法]采用生长速率法测定6种植物丙酮抽提物对病原菌菌丝生长的抑制效果,并进一步开展大蒜粉、苍耳提取物防治番茄早疫病的田间试验.[结果]大蒜、石榴提取物对多种植物病原菌的菌丝都有明显的抑制作用;苍耳次之;辣椒提取物主要抑制黄瓜炭疽病菌和番茄早疫病菌;蒲公英提取物主要对黄瓜炭疽病有抑制作用;侧柏叶对黄瓜白粉病菌的抑制率较高.1.5%大蒜粉防治番茄旱疫病效果较好,防效均在95%以上;其中,以2 000倍效果最佳,对成株期番茄早疫病的防治效果迭99.40%.[结论]6种植物提取物中,大蒜提取物的抑菌活性最强,1.5%大蒜素粉剂对番茄旱疫病的防治效果最佳.     

Antimicrobial photosensitive reactions

Photosensitivity reactions are recognized as unwanted adverse effects of an array of commonly administered topical or systemic medications, including nonsteroidal antiinflammatory agents, antifungals, and antimicrobials. When a drug induces photosensitivity, exogenous molecules in the skin absorb normally harmless doses of visible and UV light, leading to an acute inflammatory response. In phototoxic reactions, the damage to tissues is direct; in photoallergic reactions, it is immunologically mediated. In vitro and in vivo assay systems can assist in predicting or confirming drug photosensitivity. The incidence of photosensitivity reactions may be too low to be detected in clinical studies and may become recognized only in the postmarketing stage of drug development. Some drugs have been withdrawn because of photosensitivity effects that appeared after general release. Photosensitivity reactions have been studied for a number of topical antimicrobials and for the sulfonamides, griseofulvin, the tetracyclines, and the quinolones. Incidence and intensity of drug phototoxicity can vary widely among the different compounds of a given class of antimicrobials. When phototoxic effects are relatively low in incidence, mild, reversible, and clinically manageable, the benefits of an antimicrobial drug may well outweigh the potential for adverse photosensitivity effects.     

Antimicrobial susceptibility of Capnocytophaga

Capnocytophaga (Bacteroides ochraceus, Center for Disease Control biogroup DF-1) is associated with sepsis in granulocytopenic patients and is isolated in large numbers from the affected periodontal pockets in patients with juvenile periodontosis. The minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) of 17 antimicrobial agents for 13 strains of Capnocytophaga organisms were determined. In addition, the ratio of the MBC to the MIC for each antimicrobial agent was determined for each strain. At concentrations of 1 microgram/ml or less, penicillin, ampicillin, carbenicillin, erythromycin, and clindamycin killed 90% of the strains. At concentrations of 3.12 microgram/ml or less, tetracycline, metronidazole, cefoxitin, and chloramphenicol killed 90% of the strains. None of the aminoglycosides tested demonstrated antibacterial activity at 50 microgram/ml. Penicillin, ampicillin, carbenicillin, and cefoxitin exhibited MBC/MIC ratios of 4 or less with all strains. Erythromycin, tetracycline, and metronidazole exhibited MBC/MIC ratios of 4 or less for 12 of 13 strains. The MICs of cephalothin and cefazolin for 90% of the strains were 25 and 50 microgram/ml, respectively. The MBC/MIC ratios for these drugs were 4 or less for 12 of 13 and 7 of 13 strains, respectively. The MIC of cefamandole for 90% of the strains was 3.12 microgram/ml; however, only nine strains had an MBC/MIC ratio of 4 or less.     

Antimicrobial prophylaxis in urology

Antimicrobial prophylaxis in surgery has proven to be effective in controlled randomized trials. Usage in Urology is known at least since the '30s although its effectiveness has only become known since 1979. METHODS: Review of literature related to surgical antibiotic prophylaxis, more specifically urological surgery, basically from 1991 to 1995, but without overlooking those papers that have become classics due to their impact. RESULTS AND CONCLUSIONS: Efficacy of antimicrobial prophylaxis in urological surgery is nowadays beyond all doubt. Usage is indicated in the presence of sterile urine and dosage must be short, in single dosis in the immediate pre-operative or within 24 hours after the procedure. However, there is a number of issues that deserve to be treated in more detail for better understanding. Those are the establishment of adequate prophylactic regimes in renal transplantation and the use of antimicrobials based on their pharmacokinetic characteristics to optimize the prophylactic purpose.     

含银无机抗菌剂的研制和抗菌性能初探

采用不同工艺制备了载银磷酸钙和载银碳酸钙粉末 ,通过大肠杆菌培养实验 (抑菌环法 )比较了银离子存在形式对抑菌性能的影响 ,证实了银离子释放是灭菌的关键。     

Antimicrobial resistance: dentistry''s role

OBJECTIVES: To investigate the following questions. (1) Is silica dust on its own, without the presence of silicosis, associated with an increased risk of pulmonary tuberculosis (PTB) in workers exposed to silica dust? (2) In the absence of silicosis is the excess risk dose related? (3) What is the predominant chronological sequence between the development of PTB and the development of silicosis after the end of exposure to dust? METHODS: A cohort of 2255 white South African gold miners has been followed up from 1968 to 1971, when they were 45-55 years of age, to 31 December 1995 for the incidence of PTB. During the follow up 1592 (71%) men died. Of these, 1296 (81%) had a necropsy done at the National Centre for Occupational Health (NCOH) to determine the presence of silicosis and PTB. The incidence of PTB in the cohort was studied relative to cumulative exposure to dust and the onset of silicosis. For the miners with necropsy, the incidence for PTB was studied relative to the severity of silicosis found at necropsy. RESULTS: There were 115 subjects who developed PTB. The total person-years of follow up was 39,319. For the whole cohort, the factors associated with increased risk of PTB were cumulative exposure to dust (mg/m3.y) (the adjusted rate ratio (RR) 1.07; (95% confidence interval (95% CI) 1.04 to 1.10)), silicosis diagnosed radiologically (3.96 (2.59 to 6.06)), and tobacco pack-years (1.02 (1.01 to 1.03)). The RR (95% CI) for PTB increased with increasing quartiles of cumulative exposure to dust 1.0, 1.51 (0.78 to 2.91), 2.35 (1.28 to 4.32), and 3.22 (1.75 to 5.90). In miners who did not have radiologically diagnosed silicosis (n = 1934, PTB = 74), the adjusted RR (95% CI) for PTB and cumulative exposure to dust was 1.10 (1.06 to 1.13), and increased with quartiles of cumulative exposure to dust as 1.00, 1.46 (0.70 to 3.03), 2.67 (1.37 to 5.23), and 4.01 (2.04 to 7.88). For the subjects who had a necropsy (n = 1296, PTB = 70), the adjusted RR (95% CI) for PTB increased with the severity of silicosis found at necropsy; 1.0 for no silicosis, 1.88 (0.97 to 3.64) for negligible, 2.69 (1.35 to 5.37) for slight, and 2.30 (1.16 to 4.58) for moderate or marked silicosis. For subjects who had a necropsy and no silicosis (n = 577, PTB = 18), the adjusted RR (95% CI) increased slightly with quartiles of cumulative dust 1.0, 1.11 (0.31 to 4.00), 1.42 (0.43 to 4.72), and 1.38 (0.33 to 5.62). CONCLUSION: Exposure to silica dust is a risk factor for the development of PTB in the absence of silicosis, even after exposure to silica dust ends. The risk of PTB increases with the presence of silicosis, and in miners without radiological silicosis, with quartiles of exposure to dust. The severity of silicosis diagnosed at necropsy was associated with increasing risk of PTB and even < 5 nodules--that is, undetectable radiologically--was associated with an increased risk of PTB. The diagnosis of PTB was on average 7.6 years after the end of exposure to dust, at around 60 years of age. The onset of radiological silicosis preceded the diagnosis of PTB in 90.2% of the cases with PTB who had silicosis. The results have implications for medical surveillance of workers exposed to silica dust after the end of exposure.     

Antimicrobial prophylaxis for catheter-associated bacteriuria

We evaluated short-term systemic antimicrobial prophylaxis for catheter-associated bacteriuria in women undergoing elective gynecological operations in a prospective, controlled, double-masked study. Nine of 100 placebo-treated patients acquired bacteriuria during catheterization compared with 3 of 96 of the drug-treated group. However, at the time of hospital discharge, clean-voided urine specimens were positive as frequently in the drug-treated group (8 of 82 patients cultured) as in the placebo group (8 of 75 patients cultured). No difference in febrile morbidity due to bacteriuria was noted between the prophylaxis and placebo groups. The incidence of catheter-associated bacteriuria may be reduced by antimicrobial prophylaxis. However, because the protective effect is transient and is associated with the selection of resistant organisms, prophylaxis is not indicated for patients at low risk for acquired bacteriuria and in whom the sequelae of catheter-associated infections are infrequent.     

Antimicrobial peptide defense in Drosophila

Drosophila responds to a septic injury by the rapid synthesis of antimicrobial peptides. These molecules are predominantly produced by the fat body, a functional equivalent of mammalian liver, and are secreted into the hemolymph where their concentrations can reach up to 100 microM. Six distinct antibacterial peptides (plus isoforms) and one antifungal peptide have been characterized in Drosophila and their genes cloned. The induction of the gene encoding the antifungal peptide relies on the sp?tzle/Toll/cactus gene cassette, which is involved in the control of dorsoventral patterning in the embryo, and shows interesting structural and functional similarities with cytokine-induced activation of NF-kappa B in mammalian cells. An additional pathway, dependent on the as yet unidentified imd (for immune-deficiency) gene, is required for the full induction of the antibacterial peptide genes. Mutants deficient for the Toll and imd pathways exhibit a severely reduced survival to fungal and bacterial infections, respectively. Recent data on the molecular mechanisms underlying recognition of non-self are also discussed in this review.     

Antimicrobial activity of novel furanonaphthoquinone analogs

Analogs of furanonaphthoquinone (FNQ) from Tecoma ipe Mart had MICs ranging from 1.56 to 25 microg/ml against gram-positive bacteria. FNQ showed significantly lower MICs against methicillin-resistant Staphylococcus aureus than against methicillin-sensitive S. aureus. FNQ inhibited Helicobacter pylori with an MIC of 0.1 microg/ml. Fungi, including pathogenic species, were sensitive to FNQ with MICs similar to those of amphotericin B.     

Antimicrobial prescribing in patients on haemofiltration

Continuous haemo(dia)filtration techniques as a means of extracorporeal renal replacement therapy are being used more and more, especially on intensive care units. The effect of intermittent haemodialysis on the pharmacokinetics of systemic antibiotics is well documented and advice is provided in the drug data sheets regarding dosage, timing and additional doses (post haemodialysis). Continuous haemofiltration significantly alters the handling of these same antibiotics compared with haemodialysis, such that if the advice given for 'haemodialysis' is used for patients on haemofiltration, under-dosing the patient may lead to sub-therapeutic antibiotic levels. The reasons for these differences are discussed and suggested dosage modifications are given for commonly used antimicrobials based on available published data.     

Antimicrobial abietane diterpenoids from Plectranthus elegans

Two novel abietane diterpenoids have been isolated from the aerial material of Plectranthus elegans and identified as 11-hydroxy-12-oxo-7,9(11),13-abietatriene and 7 alpha,11-dihydroxy-12-methoxy-8,11,13-abietatriene. Their structures were determined through rigorous use of spectroscopic methods. Both inhibited spore germination of the fungus Cladosporium cucumerinum, in direct bioautography, at a dose of 1 microgram. The new diterpenes also inhibited the growth of Gram-positive bacteria, in the concentration range 10-40 micrograms ml-1 in broth dilution assay. No effect was observed against Gram-negative bacteria. The ecological implications of these findings are discussed.