Amides from Streptomyces hygroscopicus and their antimicrobial activity [corrected

Three amides, N-salicyloyl-2-aminopropan-1,3-diol (1) and 1-acetyl-N-salicyloyl-2-aminopropan-3-ol (2) including a natural product, N-salicyloyl-2-aminopropan-1-ol (3) were isolated from an ethyl acetate extract of the culture filtrate of Streptomyces hygroscopicus [corrected] The structures of these compounds were unambiguously established by interpretation of their spectral data including, a series of 1D and 2D-NMR and MS analyses. Compounds 1-3 showed significant antibacterial activity against a wide range of Gram positive and Gram negative bacteria.     

临床病原菌种类及耐药性监测

目的 探讨病原菌种类及其对抗菌药物的耐的耐药状况。方法 收集１９９８年１月－１９９９年１２月临床感染标本分离的病原菌并分析其种类,药敏试验采用Ｋｉｒｂｙ－Ｂａｕｅｒ纸片扩散法。结果 １１８２株病原菌,革兰氏阳性球菌６０４株（５１．１％）,革兰氏阴性杆菌５７８株（４８．９％）。病原菌以金黄一萄球菌、大肠埃希菌、表皮葡萄球菌、铜绿假单胞菌最多见。去甲万古霉素、阿米卡星、新霉素对革兰氏阳性球菌抗菌作用较     

Antimicrobial potentiality of a new non-antibiotic: the cardiovascular drug oxyfedrine hydrochloride

Ten cardiovascular drugs, having diverse pharmacological action, were screened for possible antimicrobial property against known eight sensitive bacteria, belonging to Gram positive and Gram negative types. Although five drugs failed to show antimicrobial activity and three had moderate antimicrobial action, oxyfedrine HCl and dobutamine were seen to possess pronounced antimicrobial property. Oxyfedrine was further tested in vitro against 471 strains of bacteria from two Gram positive and fourteen Gram negative genera. The minimum inhibitory concentration (MIC) of oxyfedrine was determined by agar dilution method, which ranged from 50-200 microg/ml in most of the strains, while some strains were inhibited at even lower concentrations. In animal experiments, this compound was capable of offering significant protection to Swiss strain of white mice, challenged with 50 median lethal dose (MLD) of a virulent strain of Salmonella typhimurium at concentrations of 15, 30 and 60 microg/mouse. The in vivo results were highly significant according to chi-square test.     

胸腹水培养中的病原菌分布及耐药性分析

目的了解胸腹水培养中病原菌的分布和耐药情况,为临床合理用药提供依据。方法通过回顾性分析中山市第二人民医院住院部自2011年1月至2013年11月送检的胸腹水标本细菌培养及药敏资料。结果在494份胸腹水标本中共检出47株病原菌,总阳性率为9.5%;其中326例胸水分离出病原菌28例,阳性率为8.59%,胸水培养中革兰阳性菌占67.86%,革兰阴性菌占32.12%,菌种较为分散;168例腹水分离出病原菌19例,阳性率为11.31%,腹水培养中革兰阴性菌占73.68%,革兰阳性菌占26.32%。检出革兰阴性病原菌对氨苄西林和四环素耐药率较高,对阿米卡星、美罗培南和亚胺培南敏感。检出革兰阳性病原菌对氨苄西林、头孢西丁和红霉素耐药率高,对万古霉素、替考拉宁和吗啉噁酮敏感。结论应重视胸腹水标本的细菌学检查,依据药敏试验合理使用抗菌药物,减少细菌的耐药率。     

晚期肿瘤患者下呼吸道感染临床分析

目的：探讨晚期肿瘤患者下呼吸道感染的细菌学分类情况及抗生素耐药性特点。方法：采用回顾性调查107例晚期肿瘤患者并下呼吸道感染痰菌分离的病原菌并分析其特点,药敏试验采用K—B纸片法。结果：137株病原菌,G杆菌67株(48．9％)．G^ 球菌44株(32．1%),真菌26株(19．0％)。主要致病细菌依次为铜绿假单胞菌19．7％．金黄色葡萄球菌13．9％,肺炎克雷伯菌10．9％。万古霉素、新霉素、环丙沙星对G^ 球菌较敏感;环丙沙星、阿米卡星、头孢哌酮对G杆菌作用较强．其他抗菌药物对各种病原菌均呈现不同程度的耐药。结论：晚期恶性肿瘤并下呼吸道感染的病原菌多为条件致病菌,耐药率高。应加强病原菌培养及药敏监测,以指导临床科学使用抗生素。     

成人牙周炎龈下套氧菌分离鉴定及药敏试验结果分析

分离并鉴定了329例成人牙周炎龈下优势厌氧菌群,并对不同病程中的菌群变迁、厌氧菌的药物敏感性进行了分析.成人牙周炎龈下标本中厌氧菌阳性检出率为97.9%,其中以牙龈紫质单胞菌检出率最高(38.5%),具核梭杆菌次之(18.9%).随着牙周病变程度的加重,牙龈紫质单胞菌、具核梭杆菌、产黑色素普氏菌、星群厌氧链球菌、厌氧消化链球菌的检出率增高(P＜0.05),小韦荣球菌的检出率下降(P＜0.01),表明前5种厌氧菌在AP发病过程中有重要作用,小韦荣球菌与之无关.替硝唑、甲硝唑和克林霉素对438株革兰氏阴性厌氧菌的MIC90分别为1～8,2～8和4～16 mg/L,对278株革兰氏阳性厌氧菌的MIC90分别为16～32,16～64和4～16 mg/L,表明替硝唑和甲硝唑体外抗革兰氏阴性厌氧菌效果优于克林霉素,抗革兰氏阳性厌氧菌作用不如克林霉素.     

Chemical composition and biological activity of the essential oils of Senecio aegyptius var. discoideus Boiss

The essential oil of Senecio aegyptius var. discoideus flowers, leaves, stems and roots were isolated by hydrodistillation. Analysis of the oils by capillary GLC and GLC-mass spectrometry were performed and 34 out of 37 compounds were identified. The main component was isolated and characterized as 1,10-epoxyfuranoeremophilane using a combination of GLC, GLC-MS, and NMR analyses. The oils of flowers, leaves and stems were rich in monoterpene hydrocarbons while the root oil mainly contains furanoeremophilanes. Flower and leaf volatile oils showed significant level of antifungal activity against C. albicans, moderate effect against Gram positive bacteria, however, it has weak activity against Gram negative bacteria. The isolated sesquiterpene (1,10-epoxyfuranoeremophilane) exhibited substantial inhibitory activity against Gram negative bacteria.     

Brominated Diphenyl Ethers Including a New Tribromoiododiphenyl Ether from the Vietnamese Marine Sponge Arenosclera sp. and Their Antibacterial Activities

A new tribromoiododiphenyl ether ( 1 ) and eight known brominated diphenyl ethers ( 2 – 9 ) were isolated from the MeOH extract of the sponge Arenosclera sp. collected in Vietnam, using repeated open column chromatography and preparative thin layer chromatography. The chemical structure of the new compound 1 was determined by analyses of spectroscopic (1D‐ and 2D‐NMR, and MS) data and by comparison of our data with those reported in the literature. Compounds 1 , 3 , and 8 exhibited strong antibacterial activities against the Gram‐positive bacteria Bacillus subtilis and Staphylococcus aureus and the Gram‐negative bacterium Klebsiella pneumoniae with MIC values ranging from 0.8 to 6.3 μm , while compounds 5 and 7 only displayed activities against Gram‐positive bacteria with MIC values from 0.5 to 3.1 μm . Compound 2 showed activities against the four tested bacteria with MIC values ranging from 0.5 to 6.3 μm .     

Role of amino acid residues within the disulfide loop of thanatin,a potent antibiotic peptide

Thanatin, a 21-residue peptide, is an inducible insect peptide with a broad range of activity against bacteria and fungi. It has a C-terminal disulfide loop, like the frog skin secretion antimicrobial peptides of the brevinin family. In this study, we tried to find the effect of a number of amino acids between the disulfide bond. Thanatin showed stronger antibacterial activity to Gram negative bacteria than other mutants, except Th1; whereas, the mutant peptides with deletion had higher activity to Gram positive bacteria than thanatin. An increase in the number of amino acid(s) using the alanine residue decreased the antibacterial activity in all of the bacteria. Th1 with deletion of threonine at position 15 (Thr(1)(2)) showed similar antibacterial activity against Gram-negative bacteria, but had higher activity against the Gram positive bacteria. In order to study the structure-function relationship, we measured liposome disruption by the peptides and CD spectra of the peptides. Th1 also showed the highest liposome leaking activity and alpha-helical propensity in the sodium dodecyl sulfate solution, compared with other peptides. Liposome disruption activity was closely correlated with the anti-Gram positive bacterial activity. All of the peptides showed no hemolytic activity. Th1 was considered to be useful as an antimicrobial peptide with broad spectrum without toxicity     

2-Arylbenzothiazole, benzoxazole and benzimidazole derivatives as fluorogenic substrates for the detection of nitroreductase and aminopeptidase activity in clinically important bacteria

A series of 2-(2-nitrophenyl)benzothiazole 7, 2-(2-nitrophenyl)benzoxazole 10 and 2-(2-nitrophenyl)benzimidazole 13 derivatives have been synthesised and assessed as indicators of nitroreductase activity across a range of clinically important Gram negative and Gram positive bacteria. The majority of Gram negative bacteria produced strongly fluorescent colonies with substrates 7 and 10 whereas fluorescence production in Gram positive bacteria was less widespread. The l-alanine 16 and 19 and β-alanine 21 and 23 derivatives have been prepared from 2-(2-aminophenyl)benzothiazole 14 and 2-(2-aminophenyl)benzoxazole 17. These four compounds have been evaluated as indicators of aminopeptidase activity. The growth of Gram positive bacteria was generally inhibited by these substrates but fluorescent colonies were produced with the majority of Gram negative bacteria tested.     

Eggshells as hosts of bacterial communities: An experimental test of the antimicrobial egg coloration hypothesis

Oviparous animals have evolved multiple defenses to prevent microbes from penetrating their eggs and causing embryo mortality. In birds, egg constituents such as lysozyme and antibodies defend against microbial infestation, but eggshell pigments might also impact survival of bacteria. If so, microbes could exert an important selective pressure on the evolution of eggshell coloration. In a previous lab experiment, eggshell protoporphyrin caused drastic mortality in cultures of Gram positive, but not Gram negative, bacteria when exposed to light. Here, we test this “photodynamic antimicrobial hypothesis” in a field experiment. In a paired experimental design, we placed sanitized brown, protoporphyrin‐rich chicken eggs alongside white eggs that lack protoporphyrin. We deployed eggs for 48 hr without incubation, as can occur between laying and incubation, when microbial infection risk is highest. Eggs were placed on the open ground exposed to sunlight and in dark underground storm‐petrel burrows. We predicted that the proportion of Gram‐positive bacteria on brown eggs should be lower when exposed to sunlight than when kept in the dark, but we expected no such difference for white eggs. Although our data revealed variation in bacterial community composition, the proportion of Gram‐positive bacteria on eggshells did not vary by egg color, and there was no interaction between egg color and location. Instead, Gram‐positive bacteria were proportionally more common on eggs on the ground than eggs in burrows. Overall, our experiment did not support the photodynamic antimicrobial hypothesis. The diverse range of avian egg colors is generated by just two pigments, but over 10 hypotheses have been proposed for the evolution of eggshell color. If our results are generalizable, eggshell protoporphyrin might not play a substantial role in defending eggs against microbes, which narrows the field of candidate hypotheses for the evolution of avian eggshell coloration.     

Synthesis and in vitro study of novel Mannich bases as antibacterial agents

A series of novel Mannich bases derived from 5-chloro-2-methoxybenzamide and sulfonamides/amines have been synthesised and the antibacterial activities were evaluated against various Gram positive and Gram negative strains of bacteria. Some of the synthesized compounds showed superior in vitro activities as compared to their parent sulfonamides.     

开颅术后颅内感染的病原菌分布特征及耐药性分析

目的 分析行开颅手术患者术后颅内感染的病原菌分布及耐药性。方法 回顾性分析2013年6月—2017年6月在我院神经外科行开颅手术的328例患者临床资料,统计术后颅内感染发生率,并对颅内感染患者的脑脊液进行病原学分析。结果 开颅术后颅内感染的发生率为9.15%（30/328）;30例颅内感染脑脊液标本中共分离出47株病原菌,其中革兰阳性菌占65.96%（31/47）,革兰阴性菌占34.04%（16/47）;革兰阳性菌对青霉素、红霉素完全耐药,对万古霉素敏感;对苯唑西林的耐药率达90%以上,对磺胺甲恶唑/甲氨苄啶的耐药率为70%~85%,对利福平的耐药率为50%~65%,对哌拉西林/他唑巴坦的耐药率均在50%以下。革兰阴性菌对环丙沙星、氨曲南完全耐药,对亚胺培南敏感;对阿米卡星、头孢他啶的耐药率达80%以上,对头孢吡肟的耐药率为60%~75%,对头孢曲松、妥布霉素及庆大霉素的耐药率均在60%以下;其中肺炎克雷伯菌对美罗培南敏感,而鲍曼不动杆菌对美罗培南仍有耐药性,耐药率为16.67%。结论 开颅术后颅内感染的病原菌以革兰阳性菌为主,并具有多重耐药特点,临床上应加强颅内感染的病原菌监测,同时结合药敏分析结果,合理使用抗菌药物。     

小儿细菌性肺炎痰培养物病原菌构成及耐药性分析

目的 分析肺炎患儿痰培养物中细菌构成及其耐药情况,为小儿细菌性肺炎治疗提供合理使用抗感染药物的依据。 方法 对2019年11月至2020年12月济宁市第一人民医院临床送检的肺炎患儿痰液标本进行病原菌的分离鉴定和药敏试验,收集相关资料,并对小儿肺炎病原菌在临床上的分布特点及其耐药情况进一步分析。 结果 痰液培养阳性患儿183例,其中多重细菌感染患儿16例,共培养出199株细菌(剔除同一患儿的重复菌株),其中革兰阴性菌128株(64.32%),革兰阳性菌71株(35.68%)。主流细菌为肺炎链球菌(19.60%)、金黄色葡萄球菌(16.08%)、卡他莫拉菌(13.57%)、肺炎克雷伯菌(11.06%)和大肠埃希菌(10.05%)。多重细菌感染主要以金黄色葡萄球菌+肺炎克雷伯菌、金黄色葡萄球菌+大肠埃希菌混合为主(共5例,31.25%)。肺炎链球菌和金黄色葡萄球菌对利奈唑胺、万古霉素绝对敏感。卡他莫拉菌对头孢噻肟、头孢曲松、米诺环素等绝对敏感。肠杆菌科中肺炎克雷伯菌和大肠埃希菌药敏结果相似,对阿米卡星、厄他培南、头孢替坦敏感率在95%~100%,对氨苄西林耐药率在95%~100%。肺炎链球菌、金黄色葡萄球菌、卡他莫拉菌对左氧氟沙星敏感率均大于90%,大肠埃希菌、肺炎克雷伯菌对左氧氟沙星不够敏感,但中敏率达到75%以上。 结论 肺炎链球菌、金黄色葡萄球菌、卡他莫拉菌、肺炎克雷伯菌、大肠埃希菌感染是本地肺炎患儿痰液中常见菌,抗生素耐药状况比较严重,亚胺培南对革兰阴性菌混合感染的效果较好,利奈唑胺对阳性菌效果较好;左氧氟沙星可用于革兰阴性和阳性菌混合感染,合理使用抗生素应注意针对性和用药时间,杀灭致病菌的同时尽可能维护正常菌群的平衡。     

Bacterial lipid composition and the antimicrobial efficacy of cationic steroid compounds (Ceragenins)

Ceragenins are cationic bile salt derivatives having antimicrobial activity. The interactions of several ceragenins with phospholipid bilayers were tested in different systems. The ceragenins are capable of forming specific associations with several phospholipid species that may be involved with their antimicrobial action. Their antimicrobial activity is lower in bacteria that have a high content of phosphatidylethanolamine. Gram negative bacteria with a high content of phosphatidylethanolamine exhibit sensitivity to different ceragenins that corresponds to the extent of interaction of these compounds with phospholipids, including the ability of different ceragenins to induce leakage of aqueous contents from phosphatidylethanolamine-rich liposomes. A second class of bacteria having cell membranes composed largely of anionic lipids and having a low content of phosphatidylethanolamine are very sensitive to the action of the ceragenins but they exhibit similar minimal inhibitory concentrations with most of the ceragenins and for different strains of bacteria. Although Gram negative bacteria generally have a high content of phosphatidylethanolamine, there are a few exceptions. In addition, a mutant strain of Escherichia coli has been made that is essentially devoid of phophatidylethanolamine, although 80% of the lipid of the wild-type strain is phosphatidylethanolamine. Furthermore, certain Gram positive bacteria are also exceptions in that they can have a high content of phosphatidylethanolamine. We find that the antimicrobial action of the ceragenins correlates better with the content of phosphatidylethanolamine in the bacterial membrane than whether or not the bacteria has an outer membrane. Thus, the bacterial lipid composition can be an important factor in determining the sensitivity of bacteria to antimicrobial agents.     

Antibiotic Production by Cutaneous Brevibacterium sp.

Three isolates of a Brevibacterium species isolated from human skin produced an antibiotic active against Gram positive and Gram negative bacteria. The active compound is most probably a peptide with'a molecular weight in the range 1100–1400; there is chromatographic similarity to compounds such as tyrothricin. Production of such a compound in vivo could contribute to microbial interaction in, for example, tinea pedis.     

Antimicrobial activity of isopteropodine

Bioassay-directed fractionation for the determination of antimicrobial activity of Uncaria tomentosa, has led to the isolation of isopteropodine (0.3%), a known Uncaria pentacyclic oxindol alkaloid that exhibited antibacterial activity against Gram positive bacteria.     

A novel cysteine‐free venom peptide with strong antimicrobial activity against antibiotics‐resistant pathogens from the scorpion Opistophthalmus glabrifrons

Antibiotic‐resistant bacteria, such as methicillin‐resistant Staphylococcus aureus and vancomycin‐resistant Enterococcus, pose serious threat to human health. The outbreak of antibiotic‐resistant pathogens in recent years emphasizes once again the urgent need for the development of new antimicrobial agents. Here, we discovered a novel antimicrobial peptide from the scorpion Opistophthalmus glabrifrons, which was referred to as Opisin. Opisin consists of 19 amino acid residues without disulfide bridges. It is a cationic, amphipathic, and α‐helical molecule. Protein sequence homology search revealed that Opisin shares 42.1–5.3% sequence identities to the 17/18‐mer antimicrobial peptides from scorpions. Antimicrobial assay showed that Opisin is able to potently inhibit the growth of the tested Gram‐positive bacteria with the minimal inhibitory concentration (MIC) values of 4.0–10.0 μM; in contrast, it possesses much lower activity against the tested Gram‐negative bacteria and a fungus. It is interesting to see that Opisin is able to strongly inhibit the growth of methicillin‐ and vancomycin‐resistant pathogens with the MICs ranging from 2.0 to 4.0 μM and from 4.0 to 6.0 μM, respectively. We found that at a concentration of 5 × MIC, Opisin completely killed all the cultured methicillin‐resistant Staphylococcus aureus. These results suggest that Opisin is a promising therapeutic candidate for the treatment of the antibiotic‐resistant bacterial infections. Copyright © 2015 European Peptide Society and John Wiley & Sons, Ltd.     

Gram‐positive bacteria produce membrane vesicles: Proteomics‐based characterization of Staphylococcus aureus‐derived membrane vesicles

Although archaea, Gram‐negative bacteria, and mammalian cells constitutively secrete membrane vesicles (MVs) as a mechanism for cell‐free intercellular communication, this cellular process has been overlooked in Gram‐positive bacteria. Here, we found for the first time that Gram‐positive bacteria naturally produce MVs into the extracellular milieu. Further characterizations showed that the density and size of Staphylococcus aureus‐derived MVs are both similar to those of Gram‐negative bacteria. With a proteomics approach, we identified with high confidence a total of 90 protein components of S. aureus‐derived MVs. In the group of identified proteins, the highly enriched extracellular proteins suggested that a specific sorting mechanism for vesicular proteins exists. We also identified proteins that facilitate the transfer of proteins to other bacteria, as well to eliminate competing organisms, antibiotic resistance, pathological functions in systemic infections, and MV biogenesis. Taken together, these observations suggest that the secretion of MVs is an evolutionally conserved, universal process that occurs from simple organisms to complex multicellular organisms. This information will help us not only to elucidate the biogenesis and functions of MVs, but also to develop therapeutic tools for vaccines, diagnosis, and antibiotics effective against pathogenic strains of Gram‐positive bacteria.     

Bacteriological pattern of acute purulent balanoposthitis in children

The microflora of the prepucial sac in 94 children (aged 2 months to 15 years) with acute purulent balanoposthitis (APB) was studied. In the overwhelming majority of cases APB in children was caused by facultative anaerobic and aerobic bacteria (96.7%); of these, Gram positive bacteria occurred most frequently (85.7% of cases). In 51.6% of children these bacteria were represented by staphylococci, constituting 60.3% of all Gram positive flora. Gram negative bacteria were isolated in 40.6% of cases, Escherichia coli taking the first place among them. The isolated microflora was highly resistant to frequently used wide spectrum antibiotics.