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1

Plant essential oils as active antimicrobial agents.  

PubMed

Essential oils derived from plants have been recognized for decades to exhibit biological activities, including antioxidant, anticancer, and antimicrobial attributes. Antimicrobial activities of these natural plant materials have been intensively explored in recent years, mainly in response to the overwhelming concern of consumers over the safety of synthetic food additives. Gram-negative organisms are believed to be slightly less sensitive to essential oils than Gram-positive bacteria. Generally, a higher concentration is required to obtain the same efficacy in foods than in synthetic media. The combinations of different types of essential oils or with other food additives have been found to potentially exhibit synergistic if not additive effects. This suggests a cost-efficient and wholesome alternative to both food industry and consumers, at the same time adhering to the hurdle technology in inhibiting proliferation of foodborne pathogens. This review aims to examine the conventional methods commonly used for assessment of antimicrobial activities of essential oils and phytochemicals, the use of these substances as antimicrobials in food products, factors that affect their efficacy, synergism between components or with available food preservatives as well as the challenges and future directions of using essential oils and phytochemicals as natural food preservatives. PMID:24261536

Seow, Yi Xin; Yeo, Chia Rou; Chung, Hui Ling; Yuk, Hyun-Gyun

2014-01-01

2

Peptide Antimicrobial Agents  

PubMed Central

Antimicrobial host defense peptides are produced by all complex organisms as well as some microbes and have diverse and complex antimicrobial activities. Collectively these peptides demonstrate a broad range of antiviral and antibacterial activities and modes of action, and it is important to distinguish between direct microbicidal and indirect activities against such pathogens. The structural requirements of peptides for antiviral and antibacterial activities are evaluated in light of the diverse set of primary and secondary structures described for host defense peptides. Peptides with antifungal and antiparasitic activities are discussed in less detail, although the broad-spectrum activities of such peptides indicate that they are important host defense molecules. Knowledge regarding the relationship between peptide structure and function as well as their mechanism of action is being applied in the design of antimicrobial peptide variants as potential novel therapeutic agents. PMID:16847082

Jenssen, Håvard; Hamill, Pamela; Hancock, Robert E. W.

2006-01-01

3

Antimicrobials for bacterial bioterrorism agents.  

PubMed

The limitations of current antimicrobials for highly virulent pathogens considered as potential bioterrorism agents drives the requirement for new antimicrobials that are suitable for use in populations in the event of a deliberate release. Strategies targeting bacterial virulence offer the potential for new countermeasures to combat bacterial bioterrorism agents, including those active against a broad spectrum of pathogens. Although early in the development of antivirulence approaches, inhibitors of bacterial type III secretion systems and cell division mechanisms show promise for the future. PMID:21707313

Sarkar-Tyson, Mitali; Atkins, Helen S

2011-06-01

4

Investigational Antimicrobial Agents of 2013  

PubMed Central

SUMMARY New antimicrobial agents are always needed to counteract the resistant pathogens that continue to be selected by current therapeutic regimens. This review provides a survey of known antimicrobial agents that were currently in clinical development in the fall of 2012 and spring of 2013. Data were collected from published literature primarily from 2010 to 2012, meeting abstracts (2011 to 2012), government websites, and company websites when appropriate. Compared to what was reported in previous surveys, a surprising number of new agents are currently in company pipelines, particularly in phase 3 clinical development. Familiar antibacterial classes of the quinolones, tetracyclines, oxazolidinones, glycopeptides, and cephalosporins are represented by entities with enhanced antimicrobial or pharmacological properties. More importantly, compounds of novel chemical structures targeting bacterial pathways not previously exploited are under development. Some of the most promising compounds include novel ?-lactamase inhibitor combinations that target many multidrug-resistant Gram-negative bacteria, a critical medical need. Although new antimicrobial agents will continue to be needed to address increasing antibiotic resistance, there are novel agents in development to tackle at least some of the more worrisome pathogens in the current nosocomial setting. PMID:24092856

Pucci, Michael J.

2013-01-01

5

Synthesis of novel spiropyrrolizidines as potent antimicrobial agents for human and plant pathogens  

Microsoft Academic Search

A series of novel dispirooxindolopyrrolizidine derivatives have been synthesized through 1,3-dipolar cycloaddition reaction of azomethine ylide generated from proline and isatin with the dipolarophile (E)-2-arylidine-1-keto carbazoles. The synthesized cycloadducts were evaluated for antimicrobial activities. Compounds 7d and 7e showed relatively good antibacterial and antifungal activities.

Govindasami Periyasami; Raghavachary Raghunathan; Gangadharan Surendiran; Narayanasamy Mathivanan

2008-01-01

6

Secondary Metabolites from Plants Inhibiting ABC Transporters and Reversing Resistance of Cancer Cells and Microbes to Cytotoxic and Antimicrobial Agents.  

PubMed

Fungal, bacterial, and cancer cells can develop resistance against antifungal, antibacterial, or anticancer agents. Mechanisms of resistance are complex and often multifactorial. Mechanisms include: (1) Activation of ATP-binding cassette (ABC) transporters, such as P-gp, which pump out lipophilic compounds that have entered a cell, (2) Activation of cytochrome p450 oxidases which can oxidize lipophilic agents to make them more hydrophilic and accessible for conjugation reaction with glucuronic acid, sulfate, or amino acids, and (3) Activation of glutathione transferase, which can conjugate xenobiotics. This review summarizes the evidence that secondary metabolites (SM) of plants, such as alkaloids, phenolics, and terpenoids can interfere with ABC transporters in cancer cells, parasites, bacteria, and fungi. Among the active natural products several lipophilic terpenoids [monoterpenes, diterpenes, triterpenes (including saponins), steroids (including cardiac glycosides), and tetraterpenes] but also some alkaloids (isoquinoline, protoberberine, quinoline, indole, monoterpene indole, and steroidal alkaloids) function probably as competitive inhibitors of P-gp, multiple resistance-associated protein 1, and Breast cancer resistance protein in cancer cells, or efflux pumps in bacteria (NorA) and fungi. More polar phenolics (phenolic acids, flavonoids, catechins, chalcones, xanthones, stilbenes, anthocyanins, tannins, anthraquinones, and naphthoquinones) directly inhibit proteins forming several hydrogen and ionic bonds and thus disturbing the 3D structure of the transporters. The natural products may be interesting in medicine or agriculture as they can enhance the activity of active chemotherapeutics or pesticides or even reverse multidrug resistance, at least partially, of adapted and resistant cells. If these SM are applied in combination with a cytotoxic or antimicrobial agent, they may reverse resistance in a synergistic fashion. PMID:22536197

Wink, Michael; Ashour, Mohamed L; El-Readi, Mahmoud Zaki

2012-01-01

7

Screening of natural products for antimicrobial agents  

Microsoft Academic Search

Antimicrobial research is geared toward the discovery and development of novel chemical structures such as therapeutic antimicrobial agents. The continuing problem of development of resistance to existing antibacterial agents and the dearth of good antifungal agents motivates this effort toward innovation. Selection of possible new enzyme targets for antibiotic inhibition may be made on theoretical grounds, but it appears premature

L. Silver; K. Bostian

1990-01-01

8

Overview on plant antimicrobial peptides.  

PubMed

Mechanisms related to biotic interactions, such as pathogen attack, herbivory and symbiosis are important challenges to higher plants and have been widely studied especially for breeding purposes. The present review focuses on a special category of defense molecules, the plant antimicrobial peptides, providing an overview of their main molecular features and structures. PMID:20088772

Benko-Iseppon, Ana Maria; Galdino, Suely Lins; Calsa, Tercilio; Kido, Ederson Akio; Tossi, Alessandro; Belarmino, Luis Carlos; Crovella, Sergio

2010-05-01

9

In-plant Validation of Two Antimicrobial Agents Applied During the Production of Tenderized and/or Enhanced Beef Products  

E-print Network

as antimicrobial interventions, which must be validated to eliminate or reduce E. coli O157:H7 to an undetectable level. Rifampicin-resistant Biotype I E. coli O157:H7 surrogate microorganisms (ATCC BAA-1427, BAA-1428, and BAA-1430) were applied as a cocktail (7...

Nelson, Kayla

2013-08-28

10

Bdellovibrio bacteriovorus : A future antimicrobial agent?  

PubMed Central

Bdellovibrio and like organisms (BALOs) are small, predatory, Deltaproteobacteria that prey on other Gram-negative pathogens. Many authors have unfolded the possible use of BALOs as biological control agents in environmental as well as medical microbiological settings. They are found strongly associated with natural biofilms and recent studies have shown that effective predation occurs in these naturally occurring bacterial communities. Periodontal infections could also be an interesting target for the application of BALOs as biological Gram-negative bacteria and therefore potentially susceptible to BALOs antimicrobial agents. This proposition is based on the fact that almost all periodontal pathogens are predation. Accordingly, this review aims to present the evolution toward applying Bdellovibrio bacteriovorus as an antibacterial agent to deal with oral infections, general medical conditions, environmental and industrial issues. PMID:24554900

Harini, K.; Ajila, Vidya; Hegde, Shruthi

2013-01-01

11

Discovery and development of new antimicrobial agents.  

PubMed Central

The unprecedented growth in the number of new antibiotics over the past two decades has been the result of extensive research efforts that have exploited the growing body of knowledge describing the interactions of antibiotics with their targets in bacterial cells. Information gained from one class of antimicrobial agents has often been used to advance the development of other classes. In the case of beta-lactams, information on structure-activity relationships gleaned from penicillins and cephalosporins was rapidly applied to the cephamycins, monobactams, penems, and carbapenems in order to discover broad-spectrum agents with markedly improved potency. These efforts have led to the introduction of many new antibiotics that demonstrate outstanding clinical efficacy and improved pharmacokinetics in humans. The current review discusses those factors that have influenced the rapid proliferation of new antimicrobial agents, including the discovery of new lead structures from natural products and the impact of bacterial resistance development in the clinical setting. The development process for a new antibiotic is discussed in detail, from the stage of early safety testing in animals through phase I, II, and III clinical trials. PMID:2404566

Gootz, T D

1990-01-01

12

Use of antimicrobial agents in aquaculture.  

PubMed

The aquaculture industry has grown dramatically, and plays an important role in the world's food supply chain. Antimicrobial resistance in bacteria associated with food animals receives much attention, and drug use in aquaculture is also an important issue. There are many differences between aquatic and terrestrial management systems, such as the methods used for administration of drugs. Unique problems are related to the application of drugs in aquatic environments. Residual drugs in fish products can affect people who consume them, and antimicrobials released into aquatic environments can select for resistant bacteria. Moreover, these antimicrobial-resistant bacteria, or their resistance genes, can be transferred to humans. To decrease the risks associated with the use of antimicrobials, various regulations have been developed. In addition, it is necessary to prevent bacterial diseases in aquatic animals by vaccination, to improve culture systems, and to monitor the amount of antimicrobial drugs used and the prevalence of antimicrobial-resistant bacteria. PMID:22849275

Park, Y H; Hwang, S Y; Hong, M K; Kwon, K H

2012-04-01

13

Antimicrobial proteins in induced plant defense  

Microsoft Academic Search

During the past few years a wide spectrum of plant antimicrobial proteins has been detailed, and enhanced resistance has been obtained by introducing the corresponding genes into crop species to produce transgenic lines. With the aim of manipulating the plant signals that regulate an array of defense responses, the most intense research focuses on the avr—R-mediated recognition events and elucidation

Bernard Fritig; Thierry Heitz; Michel Legrand

1998-01-01

14

[Kinetics of decamethoxine, an antimicrobial agent].  

PubMed

The kinetics of decamethoxine liberation from medical antimicrobial textiles was studied. The elution of decamethoxine was shown to be a complicated diffusive-kinetic process dependent on the exposure and concentration of decamethoxine. PMID:25300114

Pali?, G K; Nazarchuk, A A; Kulakov, A I; Nazarchuk, G G; Pali?, D V; Bereza, B N; Ole?nik, D P

2014-01-01

15

Thioridazine: resurrection as an antimicrobial agent?  

PubMed Central

The emergence of multiresistant bacterial strains and the continuing burden of infectious disease globally point to the urgent need for novel affordable antimicrobial drugs. Thioridazine is a phenothiazine antipsychotic drug with well-recognized antimicrobial activity, but this property has not been harnessed for clinical use as a result of its central nervous system and cardiac side-effects. The cardiotoxicity of thioridazine has recently been shown to be structurally specific at a molecular level, whereas its antimicrobial properties are shared by a number of phenothiazine analogues. This raises the possibility that its enantiomers or its inactive metabolite, the ring sulphoxide, may act as a lead compound in the future development of antimicrobial drugs to face the new challenges in infectious disease. PMID:17764469

Thanacoody, H K R

2007-01-01

16

Sensitivity of Bacteroides fragilis to seven antimicrobial agents.  

PubMed

The sensitivity of 100 isolates of Bacteroides fragilis 7 antimicrobial agents was determined using Wilkens-Chalgren agar, the results of minimal inhibitory concentrations being compared with a disc diffusion technique. There was reasonable correlation between the 2 methods, both of which revealed that 4 strains were highly resistant to clindamycin. In those hospitals where clindamycin is frequently used for the treatment of serious anaerobic infections, antimicrobial sensitivity testing of B. fragilis may be worthwhile. PMID:7335376

Oitmaa, M; Benn, R

1981-10-01

17

Antimicrobial and cytotoxic effects of Mexican medicinal plants.  

PubMed

The antimicrobial effects of the Mexican medicinal plants Guazuma ulmifolia, Justicia spicigera, Opuntia joconostle, O. leucotricha, Parkinsonia aculeata, Phoradendron longifolium, P. serotinum, Psittacanthus calyculatus, Tecoma stans and Teucrium cubense were tested against several human multi-drug resistant pathogens, including three Gram (+) and five Gram (-) bacterial species and three fungal species using the disk-diffusion assay. The cytotoxicity of plant extracts on human cancer cell lines and human normal non-cancerous cells was also evaluated using the MTT assay. Phoradendron longifolium, Teucrium cubense, Opuntia joconostle, Tecoma stans and Guazuma ulmifolia showed potent antimicrobial effects against at least one multidrug-resistant microorganism (inhibition zone > 15 mm). Only Justicia spicigera and Phoradendron serotinum extracts exerted active cytotoxic effects on human breast cancer cells (IC50 < or = 30 microg/mL). The results showed that Guazuma ulmifolia produced potent antimicrobial effects against Candida albicans and Acinetobacter lwoffii, whereas Justicia spicigera and Phoradendron serotinum exerted the highest toxic effects on MCF-7 and HeLa, respectively, which are human cancer cell lines. These three plant species may be important sources of antimicrobial and cytotoxic agents. PMID:22312741

Jacobo-Salcedo, Maria del Rosario; Alonso-Castro, Angel Josabad; Salazar-Olivo, Luis A; Carranza-Alvarez, Candy; González-Espíndola, Luis Angel; Domínguez, Fabiola; Maciel-Torres, Sandra Patricia; García-Lujan, Concepción; González-Martínez, Marisela del Rocio; Gómez-Sánchez, Maricela; Estrada-Castillón, Eduardo; Zapata-Bustos, Rocio; Medellin-Milán, Pedro; García-Carrancá, Alejandro

2011-12-01

18

In vitro susceptibility of Trichomonas vaginalis to 50 antimicrobial agents.  

PubMed Central

We determined the susceptibilities of five strains of Trichomonas vaginalis, one of which was metronidazole resistant, to 50 antimicrobial agents. For the metronidazole-susceptible strains, the most active agents were metronidazole, tinidazole, mebendazole, furazolidone, and anisomycin. Against the resistant strain mebendazole, furazolidone, and anisomycin were the most active. Antifungal agents, beta-lactams, macrolides, aminoglycosides, and folic acid antagonists were ineffective against all strains. PMID:3258142

Sears, S D; O'Hare, J

1988-01-01

19

Quaternized Chitosan as an Antimicrobial Agent: Antimicrobial Activity, Mechanism of Action and Biomedical Applications in Orthopedics  

PubMed Central

Chitosan (CS) is a linear polysaccharide with good biodegradability, biocompatibility and antimicrobial activity, which makes it potentially useful for biomedical applications, including an antimicrobial agent either alone or blended with other polymers. However, the poor solubility of CS in most solvents at neutral or high pH substantially limits its use. Quaternary ammonium CS, which was prepared by introducing a quaternary ammonium group on a dissociative hydroxyl group or amino group of the CS, exhibited improved water solubility and stronger antibacterial activity relative to CS over an entire range of pH values; thus, this quaternary modification increases the potential biomedical applications of CS in the field of anti-infection. This review discusses the current findings on the antimicrobial properties of quaternized CS synthesized using different methods and the mechanisms of its antimicrobial actions. The potential antimicrobial applications in the orthopedic field and perspectives regarding future studies in this field are also considered. PMID:23325051

Tan, Honglue; Ma, Rui; Lin, Chucheng; Liu, Ziwei; Tang, Tingting

2013-01-01

20

Lipid complexes with cationic peptides and OAKs; their role in antimicrobial action and in the delivery of antimicrobial agents  

Microsoft Academic Search

Antimicrobial agents are toxic to bacteria by a variety of mechanisms. One mechanism that is very dependent on the lipid composition\\u000a of the bacterial membrane is the clustering of anionic lipid by cationic antimicrobial agents. Certain species of oligo-acyl-lysine\\u000a (OAK) antimicrobial agents are particularly effective in clustering anionic lipids in mixtures mimicking the composition of\\u000a bacterial membranes. The clustering of

Raquel F. Epand; Amram Mor; Richard M. Epand

2011-01-01

21

Development of Non-Natural Flavanones as Antimicrobial Agents  

Microsoft Academic Search

With growing concerns over multidrug resistance microorganisms, particularly strains of bacteria and fungi, evolving to become resistant to the antimicrobial agents used against them, the identification of new molecular targets becomes paramount for novel treatment options. Recently, the use of new treatments containing multiple active ingredients has been shown to increase the effectiveness of existing molecules for some infections, often

Zachary L. Fowler; Karan Shah; John C. Panepinto; Amy Jacobs; Mattheos A. G. Koffas; Martin W. Brechbiel

2011-01-01

22

Plasma pharmacokinetics of antimicrobial agents in critically ill patients.  

PubMed

Prompt optimal antimicrobial treatment in critically ill patients is mandatory and must be achieved not only in terms of spectrum of activity, but also in terms of exposure at the infection site. Plasma profile of antimicrobial agents may represent a valid surrogate marker of drug exposure and allow to identify the correct dosage for a given drug. However, in the critically ill patients the pharmacokinetic behavior of antimicrobials may be altered by some very peculiar pathophysiological conditions, so that dosages significantly different from those used in clinically stable patients or from those originally studied in healthy volunteers for regulatory purposes may often be needed in order to ensure optimal plasma drug exposure in such population. This is especially true for hydrophilic antimicrobials (aminoglycosides, beta-lactams, glycopeptides, lipopeptides, echinocandins, fluconazole, acyclovir, ganciclovir) whose volume of distribution and clearance may be significantly altered by these conditions. These aspects are particularly relevant in patients with severe sepsis or with septic shock for whom the time for being considered as a special population to be studied apart from the general population has probably come. From the healthcare system perspective, this means that individualization of antimicrobial therapy by means of a real time therapeutic drug monitoring coupled with clinical pharmacological advice should be considered an invaluable tool for optimizing antimicrobial therapy and for the containment of microbial resistance in this setting. PMID:22946868

Pea, Federico

2013-02-01

23

Antimicrobial Peptides as Infection Imaging Agents: Better Than Radiolabeled Antibiotics  

PubMed Central

Nuclear medicine imaging techniques offer whole body imaging for localization of number and site of infective foci inspite of limitation of spatial resolution. The innate human immune system contains a large member of important elements including antimicrobial peptides to combat any form of infection. However, development of antibiotics against bacteria progressed rapidly and gained popularity over antimicrobial peptides but even powerful antimicrobials failed to reduce morbidity and mortality due to emergence of mutant strains of bacteria resulting in antimicrobial resistance. Differentiation between infection and inflammation using radiolabeled compounds with nuclear medicine techniques has always been a dilemma which is still to be resolved. Starting from nonspecific tracers to specific radiolabeled tracers, the question is still unanswered. Specific radiolabeled tracers included antibiotics and antimicrobial peptides which bind directly to the bacteria for efficient localization with advanced nuclear medicine equipments. However, there are merits and demerits attributed to each. In the current paper, radiolabeled antibiotics and radiolabeled peptides for infection localization have been discussed starting with the background of primitive nonspecific tracers. Radiolabeled antimicrobial peptides have certain merits compared with labeled antibiotics which make them superior agents for localization of infective focus. PMID:22675369

Akhtar, Muammad Saeed; Imran, Muhammad Babar; Nadeem, Muhammad Afzal; Shahid, Abubaker

2012-01-01

24

Antimicrobial potential of some plant extracts against Candida species.  

PubMed

The increase in the resistance to antimicrobial drugs in use has attracted the attention of the scientific community, and medicinal plants have been extensively studied as alternative agents for the prevention of infections. The Candida genus yeast can become an opportunistic pathogen causing disease in immunosuppressive hosts. The purpose of this study was to evaluate dichloromethane and methanol extracts from Mentha piperita, Rosmarinus officinalis, Arrabidaea chica, Tabebuia avellanedae, Punica granatum and Syzygium cumini against Candida species through the analysis of Minimum Inhibitory Concentration (MIC). Results presented activity of these extracts against Candida species, especially the methanol extract. PMID:21180915

Höfling, J F; Anibal, P C; Obando-Pereda, G A; Peixoto, I A T; Furletti, V F; Foglio, M A; Gonçalves, R B

2010-11-01

25

The disposition of five therapeutically important antimicrobial agents in llamas.  

PubMed

The disposition of five therapeutic antimicrobial agents was studied in llamas (Lama glama) following intravenous bolus administration. Six llamas were each given ampicillin, tobramycin, trimethoprim, sulfamethoxazole, enrofloxacin and ceftiofur at a dose of 12 mg/kg, 1 mg/kg, 3 mg/kg, 15 mg/kg, 5 mg/kg, and 2.2 mg/kg of body weight, respectively, with a wash out period of at least 3 days between treatments. Plasma concentrations of these antimicrobial agents over 12 h following i.v. bolus dosing were determined by reverse phase HPLC. Disposition of the five antimicrobial agents was described by a two compartment open model with elimination from the central compartment, and also by non-compartmental methods. From compartmental analysis, the elimination rate constant, half-life, and apparent volume of distribution in the central compartment were determined. Statistical moment theory was used to determine noncompartmental pharmacokinetic parameters of mean residence time, clearance, and volume of distribution at steady state. Based on the disposition parameters determined, and stated assumptions of likely effective minimum inhibitory concentrations (MIC) a dose and dosing interval for each of five antimicrobial agents were suggested as 6 mg/kg every 12 h for ampicillin; 4 mg/kg once a day or 0.75 mg/kg every 8 h for tobramycin; 3.0 mg/kg/15 mg/kg every 12 h for trimethoprim/sulfamethoxazole; 5 mg/kg every 12 h for enrofloxacin; and 2.2 mg/kg every 12 h for ceftiofur sodium for llamas. Steady-state peak and trough plasma concentrations were also predicted for the drugs in this study for llamas. PMID:8971671

Christensen, J M; Smith, B B; Murdane, S B; Hollingshead, N

1996-12-01

26

Essential Oils as Natural Food Antimicrobial Agents: A Review.  

PubMed

ABSTRACT Food borne illnesses pose a real scourge in the present scenario as the consumerism of packaged food has increased to a great extend. Pathogens entering the packaged foods may survive longer, which needs a check. Antimicrobial agents either alone or in combination are added to the food or packaging materials for this purpose. Exploiting the antimicrobial property, essential oils are considered as a 'natural' remedy to this problem other than its flavouring property instead of using synthetic agents. The essential oils are well known for its antibacterial, antiviral, antimycotic, antiparasitic and antioxidant properties due to the presence of phenolic functional group. Gram positive organisms are found more susceptible to the action of the essential oils. Essential oils improve the shelf-life of packaged products, control the microbial growth and unriddle the consumer concerns regarding the use of chemical preservatives. This review is intended to provide an overview of the essential oils and their role as natural antimicrobial agents in the food industry. PMID:24915323

Vergis, Jess; Gokulakrishnan, P; Agarwal, R K; Kumar, Ashok

2013-10-11

27

Sorption of antimicrobial agents in blow-fill-seal packs.  

PubMed

The present work studies the interaction of methyl paraben (MPB) and propyl paraben (PPB), two widely used antimicrobial agents in multi-dose ophthalmic formulations, with 5?mL, low density polyethylene (LDPE) and polypropylene (PP) blow-fill-seal (BFS) packs, by subjecting the systems to accelerated stability conditions of 40°C/25% RH. The effect of pH, paraben concentration, and relative humidity (RH) on the sorption loss of both the parabens was studied. Additionally, the effects of buffer species and buffer strength on MPB sorption were studied. LDPE packs showed significantly higher loss compared to PP packs which showed < 5% loss in all cases. PPB showed a significantly higher loss (40-50%) than MPB (9-16%) in LDPE. pH (3.0, 5.0, 7.0) did not have a statistically significant effect on sorption. However, concentration, humidity and buffer at pH 7 affected paraben sorption. The application of the power law suggested that the MPB followed non-Fickian diffusion while PPB showed non-Fickian to Case II diffusion in LDPE packs. In conclusion, caution should be exercised while using parabens in LDPE BFS packs because substantial losses of the antimicrobial agent during the shelf-life can compromise the preservative effectiveness against 'in-use' contamination. PMID:20887236

Amin, Aeshna; Chauhan, Sateesh; Dare, Manish; Bansal, Arvind Kumar

2012-01-01

28

Antimicrobial Activity of Indigenous Medicinal Plants Against Enterococcus  

E-print Network

. However, both the plants themselves and the shamanic knowledge of the plants are fading fast dueAntimicrobial Activity of Indigenous Medicinal Plants Against Enterococcus faecalis By Daniel The knowledge of medicinal plant use by indigenous populations constitutes the most understudied medical

Firestone, Jeremy

29

ANTIMICROBIAL PROPERTIES OF NATURAL AND SYNTHETIC PEPTIDES IN TRANSGENIC PLANTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Antimicrobial proteins and peptides (AMPs) are produced in nature by a multitude of organisms including bacteria, fungi, insects, amphibians, plants, and mammals for protection against invading microbes. Some of the antifungal proteins such as chitinases, glucanases, protease inhibitors, nucleases,...

30

Topical antimicrobial agents for the treatment of chronic wounds.  

PubMed

Chronic wounds are commonly observed in acute and community settings. The management of chronic wounds represents a significant proportion of health-care resources and makes up a substantial amount of contact time with community-based nurses spending approximately 25% to 50% of their time treating wounds. Chronic wounds often exhibit increased bacterial burden that can negatively impact upon patients, reduce their quality of life and substantially increase treatment costs for health care providers. Antibiotic resistance has become a major medical and public health problem, and interest has been generated in the use of topical therapies to manage wound infection. This article presents an overview of the historical use of honey, silver and iodine for the treatment of infected wounds progressing through to modern day use and the current evidence base for the use of these antimicrobial agents in the management of infected wounds. PMID:19749669

Ousey, Karen; McIntosh, Caroline

2009-09-01

31

Novel Zinc(II) Complexes of Heterocyclic Ligands as Antimicrobial Agents: Synthesis, Characterisation, and Antimicrobial Studies  

PubMed Central

The synthesis and antimicrobial activity of novel Zn(II) metal complexes derived from three novel heterocyclic Schiff base ligands 8-[(Z)-{[3-(N-methylamino)propyl]imino}methyl]-7-hydroxy-4-methyl-2H-chromen-2-one, 2-[(E)-{[4-(1H-1,2,4-triazol-1-ylmethyl)phenyl]imino}methyl]phenol, and (4S)-4-{4-[(E)-(2-hydroxybenzylidene)amino]benzyl}-1,3-oxazolidin-2-one have been described. These Schiff base ligands and metal complexes are characterised by spectroscopic techniques. According to these data, we propose an octahedral geometry to all the metal complexes. Antimicrobial activity of the Schiff base ligand and its metal complexes was studied against Gram negative bacteria: E. coli and Pseudomonas fluorescens, Gram positive bacteria: Staphylococcus aureus, and also against fungi, that is, C. albicans and A. niger. Some of the metal complexes show significant antifungal activity (MIC < 0.2??g/mL). The “in vitro” data has identified [Zn(NMAPIMHMC)2]·2H2O, [Zn(TMPIMP)2]·2H2O, and [Zn(HBABO)2]·2H2O as potential therapeutic antifungal agents against C. albicans and A. niger. PMID:24707242

Yamgar, Ramesh S.; Nivid, Y.; Nalawade, Satish; Mandewale, Mustapha; Atram, R. G.; Sawant, Sudhir S.

2014-01-01

32

Antimicrobial activity of 20 plants used in folkloric medicine in the Palestinian area  

Microsoft Academic Search

Ethanolic and aqueous extracts of 20 Palestinian plant species used in folk medicine were investigated for their antimicrobial activities against five bacterial species (Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris, Pseudomonas aeruginosa) and one yeast (Candida albicans). The plants showed 90% of antimicrobial activity, with significant difference in activity between the different plants. The most antimicrobially active plants were

M. S Ali-Shtayeh; Reem M.-R Yaghmour; Y. R Faidi; Khalid Salem; M. A Al-Nuri

1998-01-01

33

Antimicrobial susceptibility of viridans group streptococcal blood isolates to eight antimicrobial agents.  

PubMed

A total of 155 viridans group streptococci blood culture isolates identified by the Rapid ID32 Strep system were tested for their minimum inhibitory concentrations (MICs) to penicillin, amoxicillin, ceftriaxone, erythromycin, clindamycin, rifampicin, vancomycin and teicoplanin using the E-test. The following species were identified: S. oralis (n = 67), S. mitis (n = 66), S. sanguis (n = 7), S. salivarius (n = 5), S. parasanguis (n = 4), S. gordonii (n = 3) and S. mutans (n = 3). S. oralis and S. mitis demonstrated the highest levels of resistance to the agents tested. There were 27% of S. oralis isolates resistant to pencillin, 51% resistant to erythromycin and 6% resistant to clindamycin. For S. mitis 11% were resistant to penicillin, 40% resistant to erythromycin and 3% resistant to clindamycin. Penicillin resistant isolates (MIC > or = 2 mg/l) also demonstrated decreased susceptibility to other antimicrobial agents tested in this study. High level resistance (MIC > or = 2 mg/l) to ceftriaxone was found in 12 isolates. The isolates identified as ceftriaxone resistant comprised S. oralis (n = 7), S. mitis (n = 4) and S. parasanguis (n = 1). This study has highlighted the difference in susceptibility between different species of viridans group streptococci. These findings are of concern in the light of spread of antibiotic resistance genes from S. oralis and S. mitis to the more invasive pneumococcus. PMID:15198181

Smith, Andrew; Jackson, Margaret S; Kennedy, Helen

2004-01-01

34

Antimicrobial susceptibilities of Corynebacterium species and other non-spore-forming gram-positive bacilli to 18 antimicrobial agents.  

PubMed Central

The susceptibilities of 265 strains of Corynebacterium species and other non-spore-forming gram-positive bacilli to 18 antimicrobial agents were tested. Most strains were susceptible to vancomycin, doxycycline, and fusidic acid. Corynebacterium jeikeium and Corynebacterium urealyticum were the most resistant organisms tested. Resistance to beta-lactams, clindamycin, erythromycin, azythromycin, ciprofloxacin and gentamicin was common among strains of Corynebacterium xerosis and Corynebacterium minutissimum. Ampicillin resistance among Listeria monocytogenes was more prevalent than previously reported. Optochin, fosfomycin, and nitrofurantoin showed very little activity against most organisms tested, but the use of nitrofurantoin as a selective agent in culture medium may prevent the recovery of some isolates. Except for the unvarying activity of vancomycin against Corynebacterium species, the antimicrobial susceptibilities of the latter to other antibiotics are usually unpredictable, such that susceptibility tests are necessary for selecting the best antimicrobial treatment. PMID:7695308

Soriano, F; Zapardiel, J; Nieto, E

1995-01-01

35

Lauryl-poly-L-lysine: A New Antimicrobial Agent?  

PubMed Central

The development of multiple antibiotic resistance is a global problem. It is necessary to find new tools whose mechanisms of action differ from those of currently used antibiotics. It is known that fatty acids and cationic polypeptides are able to fight bacteria. Here, we describe the synthesis of fatty acids linked to a polypeptide with antibacterial activity. The linkage of fatty acids to a polypeptide is reported to increase the antibacterial effect of the linked fatty acid in comparison with free fatty acids (FA) or free poly-L-lysine (PLL) or a mixture of both (FA free + PLL free). A number of C6–C18 fatty acids were linked to PLL to obtain new synthetic products. These compounds were assessed in vitro to evaluate their antibacterial activity. Some fatty acid-PLLs showed a good ability to fight bacteria. Their bactericidal activity was evaluated, and, lauryl linked to PLL was found to be the most active product against both Gram-positive and Gram-negative bacteria. This new active component showed a good degree of specificity and reproducibility and its minimum inhibitory concentration (MIC) was comparatively good. The antibacterial activity of the lauryl-PLL compound suggests that it is a new and promising antimicrobial agent. PMID:24660058

Thuault, Véronique; Mangas, Arturo; Thienpont, Anne; Geffard, Michel

2014-01-01

36

Antimicrobial agent resistance in mycobacteria: molecular genetic insights.  

PubMed Central

The primary theme emerging from molecular genetic work conducted with Mycobacterium tuberculosis and several other mycobacterial species is that resistance is commonly associated with simple nucleotide alterations in target chromosomal genes rather than with acquisition of new genetic elements encoding antibiotic-altering enzymes. Mutations in an 81-bp region of the gene (rpoB) encoding the beta subunit of RNA polymerase account for rifampin resistance in 96% of M. tuberculosis and many Mycobacterium leprae isolates. Streptomycin resistance in about one-half of M. tuberculosis isolates is associated with missense mutations in the rpsL gene coding for ribosomal protein S12 or nucleotide substitutions in the 16S rRNA gene (rrs). Mutations in the katG gene resulting in catalase-peroxidase amino acid alterations nad nucleotide substitutions in the presumed regulatory region of the inhA locus are repeatedly associated with isoniazid-resistant M. tuberculosis isolates. A majority of fluoroquinolone-resistant M. tuberculosis isolates have amino acid substitutions in a region of the DNA gyrase A subunit homologous to a conserved fluoroquinolone resistance-determining region. Multidrug-resistant isolates of M. tuberculosis arise as a consequence of sequential accumulation of mutations conferring resistance to single therapeutic agents. Molecular strategies show considerable promise for rapid detection of mutations associated with antimicrobial resistance. These approaches are now amenable to utilization in an appropriately equipped clinical microbiology laboratory. PMID:8665467

Musser, J M

1995-01-01

37

Comparative physiological disposition of two nitrofuran anti-microbial agents.  

PubMed

The physiological disposition of two nitrofuran derivatives used as antimicrobial agents for the treatment of acute infectious diarrhoea was evaluated in humans and animals. Upon administration of a single oral dose (600 mg) of nifurzide or nifuroxazide, no unchanged parent drug was detected in human blood or urine. In rats given 14C-nifurzide and 14C-nifuroxazide at a dose of 10 mg kg-1, 5 per cent and 17 per cent of the dose of nifurzide and nifuroxazide, respectively, were excreted in urine over a 48-hour period. None of this radioactivity was present as unchanged drug, indicating that renal excretion of both drugs occurs as metabolites. In the faeces 20 per cent of the radioactivity recovered was associated with unchanged nifuroxazide as compared with 100 per cent for nifurzide. Whole body autoradiography using rats showed that after oral administration of 14C-nifurzide and 14C-nifuroxazide, most of the radioactivity remained in the gastrointestinal lumen. PMID:3779034

Labaune, J P; Moreau, J P; Byrne, R

1986-01-01

38

Novel Hybrid-Type Antimicrobial Agents Targeting the Switch Region of Bacterial RNA Polymerase  

PubMed Central

The bacterial RNA polymerase (RNAP) is an ideal target for the development of antimicrobial agents against drug-resistant bacteria. Especially, the switch region within RNAP has been considered as an attractive binding site for drug discovery. Here, we designed and synthesized a series of novel hybrid-type inhibitors of bacterial RNAP. The antimicrobial activities were evaluated using a paper disk diffusion assay, and selected derivatives were tested to determine their MIC values. The hybrid-type antimicrobial agent 29 showed inhibitory activity against Escherichia coli RNAP. The molecular docking study suggested that the RNAP switch region would be the binding site of 29. PMID:24900654

2013-01-01

39

Antimicrobial and phytochemical studies on 45 Indian medicinal plants against multi-drug resistant human pathogens  

Microsoft Academic Search

Ethanolic extracts of 45 Indian medicinal plants traditionally used in medicine were studied for their antimicrobial activity against certain drug-resistant bacteria and a yeast Candida albicans of clinical origin. Of these, 40 plant extracts showed varied levels of antimicrobial activity against one or more test bacteria. Anticandidal activity was detected in 24 plant extracts. Overall, broad-spectrum antimicrobial activity was observed

Iqbal Ahmad; Arina Z. Beg

2001-01-01

40

High-Level Antimicrobial Efficacy of Representative Mediterranean Natural Plant Extracts against Oral Microorganisms  

PubMed Central

Nature is an unexplored reservoir of novel phytopharmaceuticals. Since biofilm-related oral diseases often correlate with antibiotic resistance, plant-derived antimicrobial agents could enhance existing treatment options. Therefore, the rationale of the present report was to examine the antimicrobial impact of Mediterranean natural extracts on oral microorganisms. Five different extracts from Olea europaea, mastic gum, and Inula viscosa were tested against ten bacteria and one Candida albicans strain. The extraction protocols were conducted according to established experimental procedures. Two antimicrobial assays—the minimum inhibitory concentration (MIC) assay and the minimum bactericidal concentration (MBC) assay—were applied. The screened extracts were found to be active against each of the tested microorganisms. O. europaea presented MIC and MBC ranges of 0.07–10.00?mg?mL?1 and 0.60–10.00?mg?mL?1, respectively. The mean MBC values for mastic gum and I. viscosa were 0.07–10.00?mg?mL?1 and 0.15–10.00?mg?mL?1, respectively. Extracts were less effective against C. albicans and exerted bactericidal effects at a concentration range of 0.07–5.00?mg?mL?1 on strict anaerobic bacteria (Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and Parvimonas micra). Ethyl acetate I. viscosa extract and total mastic extract showed considerable antimicrobial activity against oral microorganisms and could therefore be considered as alternative natural anti-infectious agents. PMID:25054150

Cecere, Manuel; Skaltsounis, Alexios Leandros; Argyropoulou, Aikaterini; Hellwig, Elmar; Aligiannis, Nektarios

2014-01-01

41

Antimicrobial potentials of some plant species of the Bignoniaceae family.  

PubMed

The methanol extracts of the leaves and stem bark of four Bignoniaceae plants Jacaranda mimosifolia D. Dol., Tecoma stans Linn., Tabebuia rosea (Bertol) D.C., and Crescentia cujete Linn. were studied for their antimicrobial activity using a wide range of Gram-positive and Gram-negative bacteria and fungi. Extracts of both the leaves and stem bark of majority of plant species studied showed variable but remarkable broad spectrum antimicrobial activity. However, methanol extracts of Tecoma stans leaves was found to be effective against only Candida albicans at the concentrations employed. It was observed that the extracts of stem bark generally showed better antimicrobial activity than those of the leaves and some organisms were selectively more sensitive to the extracts than others. Preliminary phytochemical screening of these plants revealed the presence of tannins, flavonoids, alkaloids, quinones and traces of saponins. The antimicrobial activity observed are discussed in relation to the chemical constituents reportedly isolated from these plants and their traditional uses. PMID:7604753

Binutu, O A; Lajubutu, B A

1994-09-01

42

Antimicrobial activity of the essential oils of Turkish plant spices  

Microsoft Academic Search

The antimicrobial activity of the essential oils of nine plant spices (savory, laurel, oregano, basil, cumin, seafennel, myrtle, pickling herb, and mint) were tested at three concentrations (1, 10, and 15%) and tested on various microorganisms (Salmonella typhimurium, Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Yersinia enterocolitica, Saccharomyces cerevisiae, Candida rugosa, Rhizopus oryzae and Aspergillus niger). The results showed

M. Özcan; Osman Erkmen

2001-01-01

43

Antibiotic susceptibility of 65 isolates of Burkholderia pseudomallei and Burkholderia mallei to 35 antimicrobial agents  

Microsoft Academic Search

Objectives: Fifty isolates of Burkholderia pseudomallei and 15 isolates of Burkholderia mallei were tested for their susceptibilities to 35 antimicrobial agents, including agents not previously tested against these bacteria. Methods: MICs were determined by agar dilution in Mueller-Hinton medium. Results: Among the antibiotics tested, lower MICs were obtained with imipenem, ceftazidime, piperacil- lin, piperacillin\\/tazobactam, doxycycline and minocycline. Fluoroquinolones and aminoglycosides

F. M. Thibault; E. Hernandez; D. R. Vidal; M. Girardet; D. Cavallo

2004-01-01

44

Bacterial resistance to antimicrobial agents used in fish farming: A critical evaluation of method and meaning  

Microsoft Academic Search

The use of antimicrobial agents in aquaculture has resulted in the increase in the frequency of strains resistant to these agents. Potentially these resistant strains can have an impact on the therapy of fish diseases, the therapy of human diseases or the environment of the fish farms. The analysis of the extent of these impacts is hindered by the limited

Peter Smith; Maura Hiney; Ole Samuelsen

1994-01-01

45

Isolation and Characterization of Antimicrobial Compounds in Plant Extracts against Multidrug-Resistant Acinetobacter baumannii  

PubMed Central

The number of fully active antibiotic options that treat nosocomial infections due to multidrug-resistant Acinetobacter baumannii (A. baumannii) is extremely limited. Magnolia officinalis, Mahonia bealei, Rabdosia rubescens, Rosa rugosa, Rubus chingii, Scutellaria baicalensis, and Terminalia chebula plant extracts were previously shown to have growth inhibitory activity against a multidrug-resistant clinical strain of A. baumannii. In this study, the compounds responsible for their antimicrobial activity were identified by fractionating each plant extract using high performance liquid chromatography, and determining the antimicrobial activity of each fraction against A. baumannii. The chemical structures of the fractions inhibiting >40% of the bacterial growth were elucidated by liquid chromatography/mass spectrometry analysis and nuclear magnetic resonance spectroscopy. The six most active compounds were identified as: ellagic acid in Rosa rugosa; norwogonin in Scutellaria baicalensis; and chebulagic acid, chebulinic acid, corilagin, and terchebulin in Terminalia chebula. The most potent compound was identified as norwogonin with a minimum inhibitory concentration of 128 µg/mL, and minimum bactericidal concentration of 256 µg/mL against clinically relevant strains of A. baumannii. Combination studies of norwogonin with ten anti-Gram negative bacterial agents demonstrated that norwogonin did not enhance the antimicrobial activity of the synthetic antibiotics chosen for this study. In conclusion, of all identified antimicrobial compounds, norwogonin was the most potent against multidrug-resistant A. baumannii strains. Further studies are warranted to ascertain the prophylactic and therapeutic potential of norwogonin for infections due to multidrug-resistant A. baumannii. PMID:23630600

Miyasaki, Yoko; Rabenstein, John D.; Rhea, Joshua; Crouch, Marie-Laure; Mocek, Ulla M.; Kittell, Patricia Emmett; Morgan, Margie A.; Nichols, Wesley Stephen; Van Benschoten, M. M.; Hardy, William David; Liu, George Y.

2013-01-01

46

Occurrence of Salmonella spp. in broiler chicken carcasses and their susceptibility to antimicrobial agents  

PubMed Central

The present study was carried out to evaluate the occurrence of Salmonellae in broiler chicken carcasses and to determine the antimicrobial resistance profile of the isolated strains. Twenty-five out of the 260 broiler chicken carcasses samples (9.6%) were positive for Salmonella. S. Enteritidis was the most frequent serovar. Nineteen Salmonella isolates were tested for antimicrobial resistance, and the results indicated that 94.7% were resistant to at least one antimicrobial agent. Resistance to streptomycin (73.7%), nitrofurantoin (52.3%), tetracycline (31.6%), and nalidixic acid (21%) were the prevalent amongst Salmonella strains tested. PMID:24031401

Duarte, Dalila Angélica Moliterno; Ribeiro, Aldemir Reginato; Vasconcelos, Ana Mércia Mendes; Santos, Sylnei Barros; Silva, Juliana Vital Domingos; de Andrade, Patrícia Lúcia Arruda; de Arruda Falcão, Lúcia Sadae Pereira da Costa

2009-01-01

47

IQ-motif peptides as novel anti-microbial agents.  

PubMed

The IQ-motif is an amphipathic, often positively charged, ?-helical, calmodulin binding sequence found in a number of eukaryote signalling, transport and cytoskeletal proteins. They share common biophysical characteristics with established, cationic ?-helical antimicrobial peptides, such as the human cathelicidin LL-37. Therefore, we tested eight peptides encoding the sequences of IQ-motifs derived from the human cytoskeletal scaffolding proteins IQGAP2 and IQGAP3. Some of these peptides were able to inhibit the growth of Escherichia coli and Staphylococcus aureus with minimal inhibitory concentrations (MIC) comparable to LL-37. In addition some IQ-motifs had activity against the fungus Candida albicans. This antimicrobial activity is combined with low haemolytic activity (comparable to, or lower than, that of LL-37). Those IQ-motifs with anti-microbial activity tended to be able to bind to lipopolysaccharide. Some of these were also able to permeabilise the cell membranes of both Gram positive and Gram negative bacteria. These results demonstrate that IQ-motifs are viable lead sequences for the identification and optimisation of novel anti-microbial peptides. Thus, further investigation of the anti-microbial properties of this diverse group of sequences is merited. PMID:23238369

McLean, Denise T F; Lundy, Fionnuala T; Timson, David J

2013-04-01

48

Evaluation of three medicinal plants for anti-microbial activity  

PubMed Central

Herbal remedies have a long history of use for gum and tooth problems such as dental caries. The present microbiological study was carried out to evaluate the antimicrobial efficacy of three medicinal plants (Terminalia chebula Retz., Clitoria ternatea Linn., and Wedelia chinensis (Osbeck.) Merr.) on three pathogenic microorganisms in the oral cavity (Streptococcus mutans, Lactobacillus casei, and Staphylococcus aureus). Aqueous extract concentrations (5%, 10%, 25%, and 50%) were prepared from the fruits of Terminalia chebula, flowers of Clitoria ternatea, and leaves of Wedelia chinensis. The antimicrobial efficacy of the aqueous extract concentrations of each plant was tested using agar well diffusion method and the size of the inhibition zone was measured in millimeters. The results obtained showed that the diameter of zone of inhibition increased with increase in concentration of extract and the antimicrobial efficacy of the aqueous extracts of the three plants was observed in the increasing order – Wedelia chinensis < Clitoria ternatea < Terminalia chebula. It can be concluded that the tested extracts of all the three plants were effective against dental caries causing bacteria. PMID:23723653

Pratap, Gowd M. J. S; Manoj, Kumar M. G.; Sai, Shankar A. J.; Sujatha, B.; Sreedevi, E.

2012-01-01

49

In vitro synergistic activity between bismuth subcitrate and various antimicrobial agents against Campylobacter pyloridis (C. pylori).  

PubMed Central

The in vitro interactions between bismuth subcitrate and a variety of antimicrobial agents against 12 Campylobacter pyloridis (C. pylori) isolates were studied by the agar dilution checkerboard technique. The combination of bismuth subcitrate with the older quinolone, oxolinic acid, produced synergistic activity against all strains. This observation, however, could not be extended to the (aryl) fluoroquinolones, norfloxacin, ofloxacin, and difloxacin, since synergy was rare or absent when bismuth subcitrate was combined with these antibiotics. Among the other antimicrobial agents tested, rifampin and the beta-lactams frequently showed showed MICs for C. pyloridis similar to those of bismuth subcitrate. PMID:3674850

Van Caekenberghe, D L; Breyssens, J

1987-01-01

50

Minimum inhibitory concentrations for selected antimicrobial agents against Fusobacterium necrophorum isolated from hepatic abscesses in cattle and sheep.  

PubMed

Minimum inhibitory concentrations for 35 antimicrobial agents against 100 Fusobacterium necrophorum isolates from hepatic abscesses in sheep and cattle were determined. Twelve of the thirteen beta-lactam antibiotics tested inhibited growth of 100% of strains tested. Of the remaining antimicrobial agents, extensive susceptibility was found for: spiramycin, josamycin, lincomycin, tylosin, oxytetracycline, chlortetracycline, rufloxacin, metronidazole, cotrimoxazole, sulfadimethoxine, virginiamycin and fosfomycin. PMID:9049945

Mateos, E; Piriz, S; Valle, J; Hurtado, M; Vadillo, S

1997-02-01

51

Development of novel therapeutic drugs in humans from plant antimicrobial peptides.  

PubMed

All living organisms, ranging from microorganisms to plants and mammals, have evolved mechanisms to actively defend themselves against pathogen attack. A wide range of biological activities have been attributed to plant antimicrobial peptides (AMPs) including growth inhibitory effects on a broad range of fungi, Gram-positive and Gram-negative bacteria, viruses, neoplasic cells and parasitic protozoa. Classes of AMPs, their mechanisms of action, biological activity, and cytotoxicity towards host cells are discussed. A particular focus regards AMP candidates with potential for use in defense against biological warfare agents. This field is young, but provides additional stimulus to consideration of these molecules as a new class of therapeutic agents and promises to revolutionize treatment of many infectious diseases. PMID:20088768

da Rocha Pitta, Maira Galdino; da Rocha Pitta, Marina Galdino; Galdino, Suely Lins

2010-05-01

52

Antimicrobial Activities of Three Medicinal Plants and Investigation of Flavonoids of Tripleurospermum disciforme  

PubMed Central

Rosa damascena, Tripleurospermum disciforme and Securigera securidaca were used as disinfectant agents and for treatment of some disease in folk medicine of Iran. The antimicrobial effects of different fractions of seeds extract of S. securidaca, petals extract of R. damascena and aerial parts extract of T. disciforme were examined against some gram positive, gram negative and fungi by cup plate diffusion method. The petroleum ether and chloroform fractions of S. securidaca showed antibacterial activities against Staphylococcus aureus and Pseudomonas aeruginosa, while its methanol fraction had no antibacterial effects. R. damascena petals extract demonstrated antibacterial activities against Bacillus cereus, Staphylococcus epidermidis, S. aureus and Pseudomonas aeruginosa. T. disciforme aerial parts extract exhibited antimicrobial effects only against S. aureus and S. epidermidis. None of the fractions had any antifungal activities. Therefore, present study confirmed utility of these plants as disinfectant agents. Six flavonoids were isolated from T. disciforme: Luteolin, Quercetin-7-O-glucoside, Kaempferol, Kaempferol-7-O-glucoside, Apigenin and Apigenin-7-O-glucoside. The flavonoids and the antimicrobial activity of T. disciforme are reported for the first time. PMID:25561928

Tofighi, Zahra; Molazem, Maryam; Doostdar, Behnaz; Taban, Parisa; Shahverdi, Ahmad Reza; Samadi, Nasrin; Yassa, Narguess

2015-01-01

53

Antimicrobial Activities of Three Medicinal Plants and Investigation of Flavonoids of Tripleurospermum disciforme.  

PubMed

Rosa damascena, Tripleurospermum disciforme and Securigera securidaca were used as disinfectant agents and for treatment of some disease in folk medicine of Iran. The antimicrobial effects of different fractions of seeds extract of S. securidaca, petals extract of R. damascena and aerial parts extract of T. disciforme were examined against some gram positive, gram negative and fungi by cup plate diffusion method. The petroleum ether and chloroform fractions of S. securidaca showed antibacterial activities against Staphylococcus aureus and Pseudomonas aeruginosa, while its methanol fraction had no antibacterial effects. R. damascena petals extract demonstrated antibacterial activities against Bacillus cereus, Staphylococcus epidermidis, S. aureus and Pseudomonas aeruginosa. T. disciforme aerial parts extract exhibited antimicrobial effects only against S. aureus and S. epidermidis. None of the fractions had any antifungal activities. Therefore, present study confirmed utility of these plants as disinfectant agents. Six flavonoids were isolated from T. disciforme: Luteolin, Quercetin-7-O-glucoside, Kaempferol, Kaempferol-7-O-glucoside, Apigenin and Apigenin-7-O-glucoside. The flavonoids and the antimicrobial activity of T. disciforme are reported for the first time. PMID:25561928

Tofighi, Zahra; Molazem, Maryam; Doostdar, Behnaz; Taban, Parisa; Shahverdi, Ahmad Reza; Samadi, Nasrin; Yassa, Narguess

2015-01-01

54

Plants belonging to the genus Thymus as antibacterial agents: from farm to pharmacy.  

PubMed

In traditional medicine, plants have been used since ancient times for the prevention and/or protection against infectious diseases. In recent years, the use of herbal medicines and food supplements containing botanical ingredients, as alternative therapy for infectious diseases, has been intensified due to their high content of antimicrobial agents such as polyphenols, i.e. flavonoids, tannins, and alkaloids. Plants from the genus Thymus are important medicinal herbs, which are known to contain antimicrobial agents, and are rich in different active substances such as thymol, carvacrol, p-cymene and terpinene. In this review, we summarise the available literature data about the in vitro antibacterial effects of the main plants belonging to the genus Thymus. We also provide information about cultivation, chemical composition of the essential oils obtained from these plants, and their use for medicinal purposes. PMID:25466031

Nabavi, Seyed Mohammad; Marchese, Anna; Izadi, Morteza; Curti, Valeria; Daglia, Maria; Nabavi, Seyed Fazel

2015-04-15

55

Pectin functionalized with natural fatty acids as antimicrobial agent.  

PubMed

Several pectin derivatives were prepared by chemical modifications of the polysaccharide with natural fatty acids. The obtained biodegradable pectin-based materials, pectin-linoleate, pectin-oleate and pectin-palmitate, were investigated for their antimicrobial activity against several bacterial strains, Staphylococcus aureus and Escherichia coli. Good results were obtained for pectin-oleate and pectin-linoleate, which inhibit the growth of the selected microorganisms by 50-70%. They exert the better antimicrobial activity against S. aureus. Subsequently, the pectin-oleate and the pectin-linoleate samples were coated on polyethylene films and were assessed for their capacity to capture the oxygen molecules, reducing its penetration into the polymeric support. These results confirmed a possible application of the new materials in the field of active food packaging. PMID:24751510

Calce, Enrica; Mignogna, Eleonora; Bugatti, Valeria; Galdiero, Massimiliano; Vittoria, Vittoria; De Luca, Stefania

2014-07-01

56

Antimicrobial activity of some medicinal plants from the cerrado of the centralwestern region of Brazil.  

PubMed

Ethanol extracts from six selected species from the Cerrado of the Central-Western region of Brazil, which are used in traditional medicine for the treatment of infectious diseases and other medical conditions, namely Erythroxylum suberosum St. Hil. (Erythroxylaceae), Hyptis crenata Pohl. ex Benth. (Lamiaceae), Roupala brasiliensis Klotz. (Proteaceae), Simarouba versicolor St. Hil. (Simaroubaceae), Guazuma ulmifolia Lam. (Sterculiaceae) and Protium heptaphyllum (Aubl.) March. (Burseraceae), as well as fractions resulting from partition of these crude extracts, were screened in vitro for their antifungal and antibacterial properties. The antimicrobial activities were assessed by the broth microdilution assay against six control fungal strains, Candida albicans, C. glabrata, C. krusei, C. parapsilosis, C. tropicalis and Cryptococcus neoformans, and five control Gram-positive and negative bacterial strains, Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. Toxicity of the extracts and fractions against Artemia salina was also evaluated in this work. All plants investigated showed antimicrobial properties against at least one microorganism and two species were also significantly toxic to brine shrimp larvae. The results tend to support the traditional use of these plants for the treatment of respiratory and gastrointestinal disorders and/or skin diseases, opening the possibility of finding new antimicrobial agents from these natural sources. Among the species investigated, Hyptis crenata, Erythroxylum suberosum and Roupala brasiliensis were considered the most promising candidates for developing of future bioactivity-guided phytochemical investigations. PMID:24031956

Violante, Ivana Maria Póvoa; Hamerski, Lidilhone; Garcez, Walmir Silva; Batista, Ana Lucia; Chang, Marilene Rodrigues; Pott, Vali Joana; Garcez, Fernanda Rodrigues

2012-10-01

57

Antimicrobial activity of some medicinal plants from the cerrado of the centralwestern region of Brazil  

PubMed Central

Ethanol extracts from six selected species from the Cerrado of the Central-Western region of Brazil, which are used in traditional medicine for the treatment of infectious diseases and other medical conditions, namely Erythroxylum suberosum St. Hil. (Erythroxylaceae), Hyptis crenata Pohl. ex Benth. (Lamiaceae), Roupala brasiliensis Klotz. (Proteaceae), Simarouba versicolor St. Hil. (Simaroubaceae), Guazuma ulmifolia Lam. (Sterculiaceae) and Protium heptaphyllum (Aubl.) March. (Burseraceae), as well as fractions resulting from partition of these crude extracts, were screened in vitro for their antifungal and antibacterial properties. The antimicrobial activities were assessed by the broth microdilution assay against six control fungal strains, Candida albicans, C. glabrata, C. krusei, C. parapsilosis, C. tropicalis and Cryptococcus neoformans, and five control Gram-positive and negative bacterial strains, Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. Toxicity of the extracts and fractions against Artemia salina was also evaluated in this work. All plants investigated showed antimicrobial properties against at least one microorganism and two species were also significantly toxic to brine shrimp larvae. The results tend to support the traditional use of these plants for the treatment of respiratory and gastrointestinal disorders and/or skin diseases, opening the possibility of finding new antimicrobial agents from these natural sources. Among the species investigated, Hyptis crenata, Erythroxylum suberosum and Roupala brasiliensis were considered the most promising candidates for developing of future bioactivity-guided phytochemical investigations. PMID:24031956

Violante, Ivana Maria Póvoa; Hamerski, Lidilhone; Garcez, Walmir Silva; Batista, Ana Lucia; Chang, Marilene Rodrigues; Pott, Vali Joana; Garcez, Fernanda Rodrigues

2012-01-01

58

A Minimalist Design Approach to Antimicrobial Agents Based on a Thionin Template  

E-print Network

A Minimalist Design Approach to Antimicrobial Agents Based on a Thionin Template Miquel Vila for protein receptors.3 Several ap- proaches for the stabilization of helical structures using natural4,5 and non-natural amino acid substitutions and metal complex- ation6,7 have been reported.8-10 Covalent side

Pompeu Fabra, Universitat

59

Preliminary screening of some traditional zulu medicinal plants for anti-inflammatory and anti-microbial activities.  

PubMed

Aqueous and methanolic extracts from different parts of nine traditional Zulu medicinal plants, of the Vitaceae from KwaZulu-Natal, South Africa were evaluated for therapeutic potential as anti-inflammatory and anti-microbial agents. Of the twenty-nine crude extracts assayed for prostaglandin synthesis inhibitors, only five methanolic extracts of Cyphostemma natalitium-root, Rhoicissus digitata-leaf, R. rhomboidea-root, R. tomentosa-leaf/stem and R. tridentata-root showed significant inhibition of cyclo-oxygenase (COX-1). The extracts of R. digitata-leaf and of R. rhomboidea-root exhibited the highest inhibition of prostaglandin synthesis with 53 and 56%, respectively. The results suggest that Rhoicissus digitata leaves and of Rhoicissus rhomboidea roots may have the potential to be used as anti-inflammatory agents. All the screened plant extracts showed some degrees of anti-microbial activity against gram-positive and gram-negative microorganisms. The methanolic extracts of C. natalitium-stem and root, R. rhomboidea-root, and R. tomentosa-leaf/stem, showed different anti-microbial activities against almost all micro-organisms tested. Generally, these plant extracts inhibited the gram-positive micro-organisms more than the gram-negative ones. Several plant extracts inhibited the growth of Candida albicans while only one plant extract showed inhibitory activity against Saccharomyces cerevisiae. All the plant extracts which demonstrated good anti-inflammatory activities also showed better inhibitory activity against Candida albicans. PMID:10624887

Lin, J; Opoku, A R; Geheeb-Keller, M; Hutchings, A D; Terblanche, S E; Jäger, A K; van Staden, J

1999-12-15

60

In vitro antimicrobial activity of ten medicinal plants against clinical isolates of oral cancer cases  

PubMed Central

Background Suppression of immune system in treated cancer patients may lead to secondary infections that obviate the need of antibiotics. In the present study, an attempt was made to understand the occurrence of secondary infections in immuno-suppressed patients along with herbal control of these infections with the following objectives to: (a) isolate the microbial species from the treated oral cancer patients along with the estimation of absolute neutrophile counts of patients (b) assess the in vitro antimicrobial activity medicinal plants against the above clinical isolates. Methods Blood and oral swab cultures were taken from 40 oral cancer patients undergoing treatment in the radiotherapy unit of Regional Cancer Institute, Pt. B.D.S. Health University, Rohtak, Haryana. Clinical isolates were identified by following general microbiological, staining and biochemical methods. The absolute neutrophile counts were done by following the standard methods. The medicinal plants selected for antimicrobial activity analysis were Asphodelus tenuifolius Cav., Asparagus racemosus Willd., Balanites aegyptiaca L., Cestrum diurnum L., Cordia dichotoma G. Forst, Eclipta alba L., Murraya koenigii (L.) Spreng. , Pedalium murex L., Ricinus communis L. and Trigonella foenum graecum L. The antimicrobial efficacy of medicinal plants was evaluated by modified Kirby-Bauer disc diffusion method. MIC and MFC were investigated by serial two fold microbroth dilution method. Results Prevalent bacterial pathogens isolated were Staphylococcus aureus (23.2%), Escherichia coli (15.62%), Staphylococcus epidermidis (12.5%), Pseudomonas aeruginosa (9.37%), Klebsiella pneumonia (7.81%), Proteus mirabilis (3.6%), Proteus vulgaris (4.2%) and the fungal pathogens were Candida albicans (14.6%), Aspergillus fumigatus (9.37%). Out of 40 cases, 35 (87.5%) were observed as neutropenic. Eight medicinal plants (A. tenuifolius, A. racemosus, B. aegyptiaca, E. alba, M. koenigii, P. murex R. communis and T. foenum graecum) showed significant antimicrobial activity (P < .05) against most of the isolates. The MIC and MFC values were ranged from 31 to 500 ?g/ml. P. aeruginosa was observed highest susceptible bacteria (46.6%) on the basis of susceptible index. Conclusion It can be concluded that treated oral cancer patients were neutropenic and prone to secondary infection of microbes. The medicinal plant can prove as effective antimicrobial agent to check the secondary infections in treated cancer patients. PMID:21599889

2011-01-01

61

Metabolic Network Analysis-Based Identification of Antimicrobial Drug Targets in Category A Bioterrorism Agents  

PubMed Central

The 2001 anthrax mail attacks in the United States demonstrated the potential threat of bioterrorism, hence driving the need to develop sophisticated treatment and diagnostic protocols to counter biological warfare. Here, by performing flux balance analyses on the fully-annotated metabolic networks of multiple, whole genome-sequenced bacterial strains, we have identified a large number of metabolic enzymes as potential drug targets for each of the three Category A-designated bioterrorism agents including Bacillus anthracis, Francisella tularensis and Yersinia pestis. Nine metabolic enzymes- belonging to the coenzyme A, folate, phosphatidyl-ethanolamine and nucleic acid pathways common to all strains across the three distinct genera were identified as targets. Antimicrobial agents against some of these enzymes are available. Thus, a combination of cross species-specific antibiotics and common antimicrobials against shared targets may represent a useful combinatorial therapeutic approach against all Category A bioterrorism agents. PMID:24454817

Ahn, Yong-Yeol; Lee, Deok-Sun; Burd, Henry; Blank, William; Kapatral, Vinayak

2014-01-01

62

Antidiabetic Agents from Medicinal Plants  

Microsoft Academic Search

Currently available therapeutic options for non-insulin-dependent diabetes mellitus, such as dietary modification, oral hypoglycemics, and insulin, have limitations of their own. Many natural products and herbal medicines have been recommended for the treatment of diabetes. The present paper reviews medicinal plants that have shown experimental or clinical antidiabetic activity and that have been used in traditional systems of medicine; the

Mankil Jung; Hyun Chul Lee; Yoon-Ho Kang; Eun Seok Kang; Sang Ki Kim

2006-01-01

63

Susceptibilities of Mycoplasma bovis, Mycoplasma dispar, and Ureaplasma diversum strains to antimicrobial agents in vitro.  

PubMed Central

The purpose of this study was to determine the susceptibility of various strains of Mycoplasma bovis, Mycoplasma dispar, and Ureaplasma diversum, which are prevalent causes of pneumonia in calves, to 16 antimicrobial agents in vitro. The MICs of the antimicrobial agents were determined by a serial broth dilution method for 16 field strains and the type strain of M. bovis, for 19 field strains and the type strain of M. dispar, and for 17 field strains of U. diversum. Final MICs for M. bovis and M. dispar were read after 7 days and final MICs for U. diversum after 1 to 2 days. All strains tested were susceptible to tylosin, kitasamycin, and tiamulin but were resistant to nifuroquine and streptomycin. Most strains of U. diversum were intermediately susceptible to oxytetracycline but fully susceptible to chlortetracycline; most strains of M. bovis and M. dispar, however, were resistant to both agents. Strains of M. dispar and U. diversum were susceptible to doxycycline and minocycline, but strains of M. bovis were only intermediately susceptible. Susceptibility or resistance to chloramphenicol, spiramycin, spectinomycin, lincomycin, or enrofloxacin depended on the species but was not equal for the three species. The type strains of M. bovis and M. dispar were more susceptible to various antimicrobial agents, including tetracyclines, than the field strains. This finding might indicate that M. bovis and M. dispar strains are becoming resistant to these agents. Antimicrobial agents that are effective in vitro against all three mycoplasma species can be considered for treating mycoplasma infections in pneumonic calves. Therefore, tylosin, kitasamycin, and tiamulin may be preferred over oxytetracycline and chlortetracycline. PMID:8452363

ter Laak, E A; Noordergraaf, J H; Verschure, M H

1993-01-01

64

Antimicrobial activity of essential oils from Mediterranean aromatic plants against several foodborne and spoilage bacteria.  

PubMed

The antimicrobial activity of essential oils extracted from a variety of aromatic plants, often used in the Portuguese gastronomy was studied in vitro by the agar diffusion method. The essential oils of thyme, oregano, rosemary, verbena, basil, peppermint, pennyroyal and mint were tested against Gram-positive (Listeria monocytogenes, Clostridium perfringens, Bacillus cereus, Staphylococcus aureus, Enterococcus faecium, Enterococcus faecalis, and Staphylococcus epidermidis) and Gram-negative strains (Salmonella enterica, Escherichia coli, and Pseudomonas aeruginosa). For most essential oils examined, S. aureus, was the most susceptible bacteria, while P. aeruginosa showed, in general, least susceptibility. Among the eight essential oils evaluated, thyme, oregano and pennyroyal oils showed the greatest antimicrobial activity, followed by rosemary, peppermint and verbena, while basil and mint showed the weakest antimicrobial activity. Most of the essential oils considered in this study exhibited a significant inhibitory effect. Thyme oil showed a promising inhibitory activity even at low concentration, thus revealing its potential as a natural preservative in food products against several causal agents of foodborne diseases and food spoilage. In general, the results demonstrate that, besides flavoring the food, the use of aromatic herbs in gastronomy can also contribute to a bacteriostatic effect against pathogens. PMID:23444311

Silva, Nuno; Alves, Sofia; Gonçalves, Alexandre; Amaral, Joana S; Poeta, Patrícia

2013-12-01

65

Self-assembled cationic peptide nanoparticles as an efficient antimicrobial agent  

NASA Astrophysics Data System (ADS)

Antimicrobial cationic peptides are of interest because they can combat multi-drug-resistant microbes. Most peptides form ?-helices or ?-sheet-like structures that can insert into and subsequently disintegrate negatively charged bacterial cell surfaces. Here, we show that a novel class of core-shell nanoparticles formed by self-assembly of an amphiphilic peptide have strong antimicrobial properties against a range of bacteria, yeasts and fungi. The nanoparticles show a high therapeutic index against Staphylococcus aureus infection in mice and are more potent than their unassembled peptide counterparts. Using Staphylococcus aureus-infected meningitis rabbits, we show that the nanoparticles can cross the blood-brain barrier and suppress bacterial growth in infected brains. Taken together, these nanoparticles are promising antimicrobial agents that can be used to treat brain infections and other infectious diseases.

Liu, Lihong; Xu, Kaijin; Wang, Huaying; Jeremy Tan, P. K.; Fan, Weimin; Venkatraman, Subbu S.; Li, Lanjuan; Yang, Yi-Yan

2009-07-01

66

The in vitro efficacy of antimicrobial agents against the pathogenic free-living amoeba Balamuthia mandrillaris.  

PubMed

The free-living amoeba Balamuthia mandrillaris causes usually fatal encephalitis in humans and animals. Only limited studies have investigated the efficacy of antimicrobial agents against the organism. Assay methods were developed to assess antimicrobial efficacy against both the trophozoite and cyst stage of B. mandrillaris (ATCC 50209). Amphotericin B, ciclopirox olamine, miltefosine, natamycin, paromomycin, pentamidine isethionate, protriptyline, spiramycin, sulconazole and telithromycin had limited activity with amoebacidal levels of > 135-500 ?M. However, diminazene aceturate (Berenil(®) ) was amoebacidal at 7.8 ?M and 31.3-61.5 ?M for trophozoites and cysts, respectively. Assays for antimicrobial testing may improve the prognosis for infection and aid in the development of primary selective culture isolation media. PMID:23869955

Ahmad, Arine F; Heaselgrave, Wayne; Andrew, Peter W; Kilvington, Simon

2013-01-01

67

The Role and Efficacy of Herbal Antimicrobial Agents in Orthodontic Treatment  

PubMed Central

Aims: To assess the effect of herbal antimicrobial agents on Streptococcus mutans count in biofilm formations during orthodontic treatment. Materials and Methods: We calculated the growth inhibition of oral bacteria in the orthodontic appliances after herbal antibacterial agents were placed in culture media. The Minimum Inhibitory Concentrations (MICs) of these agents on Streptococcus mutans growth were determined. After cultivating colonies of Streptococci in biofilm medium with these herbal antimicrobial agents and orthodontic attachments, viable cell counting was performed from the bacteria which were attached on them. Scanning electron microscopy (SEM) analysis of morphology was observed on bacterial cells which were attached to orthodontic attachments. The effects of these agents were then evaluated and recommendations were forwarded. Results: There was an increase in count of Streptococcus mutans with respect to the herbal antibacterial agents. Conclusion: Despite the antibacterial functions of these herbal agents, there was increase in the biofilm formation caused by Streptococcus mutans to orthodontic bands, which had occurred most likely through upregulation of glucosyl transferase expression. These extracts may thus play an important role in increased bacterial attachment to orthodontic wires. Thus, this study was corroborative of an amalgamation of Ayurvedic therapy and Orthodontic treatment. PMID:25121056

Mishra, Sumita; Kumar Sahu, Sanjeeb; Bhusan Nanda, Smruti; Charan Sahu, Kanhu

2014-01-01

68

Genotoxic agents detected by plant bioassays.  

PubMed

Seven higher plant species (Allium cepa, Arabidopsis thaliana, Glycine max, Hordeum vulgaris. Tradescantia paludosa, Vicia faba, and Zea mays) were reviewed for their ability to detect genotoxicity of chemical agents under the U.S. Environmental Protection Agency (U.S. EPA) Gene-Tox program in the late 1970s. Six bioassays-Allium and Vicia root tip chromosome breaks, Tradescantia chromosome break, Tradescantia micronucleus, Tradescantia-stamen-hair mutation, and Arabidopsis-mutation bioassays- were established from four plant systems that are currently in use for detecting the genotoxicity of environmental agents. Under the Gene-Tox program, the Crepis capillaris-chromosome-aberration test was added to the existing six bioassays. The current review is limited to chemical agents that exhibit a positive response to any of these seven plant bioassays. From 158 articles reviewed, 84 chemicals were compiled in three categories: carcinogens, clastogens, and mutagens. As none of these plant bioassays can detect tumor initiation or cancerous growth, the chemicals were categorized as carcinogens based on their characteristics defined by the U.S. EPA's Superfund Priority 1 List and/or by the chemical listings of the Sigma and Aldrich Chemical Companies. Certain mutagens were categorized in the same manner in addition to the agents detected as mutagens by these plant bioassays. PMID:15835495

Ma, Te-Hsiu; Cabrera, Guillermo L; Owens, Elizabeth

2005-01-01

69

Strategies for transformation of naturally-occurring amphibian antimicrobial peptides into therapeutically valuable anti-infective agents  

Microsoft Academic Search

The emergence of strains of pathogenic microorganisms with resistance to commonly used antibiotics has necessitated a search for novel types of antimicrobial agents. Many frog species produce amphipathic ?-helical peptides with broad spectrum antimicrobial activity in the skin but their therapeutic potential is limited by varying degrees of cytolytic activity towards eukaryotic cells. Methods for development of such peptides into

J. Michael Conlon; Nadia Al-Ghaferi; Bency Abraham; Jérôme Leprince

2007-01-01

70

Systematic study of non-natural short cationic lipopeptides as novel broad-spectrum antimicrobial agents.  

PubMed

We describe the design and synthesis of a new series of non-natural short cationic lipopeptides (MW = 700) as antimicrobial agents. All of the synthesized lipopeptides were tested against a range of microbes such as Gram-positive, Gram-negative bacteria, fungi including methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE). By systematic study of design template, we found that three ornithine residues conjugated with myristic acid are minimum requirement for a compound to be an antimicrobial agent. The most potent lipopeptide LP16 possesses broad-spectrum antimicrobial activity and has MICs in the range of 1.5-6.25 ?g/mL against Escherichia coli, S. aureus, Pseudomonas aeruginosa, Bacillus subtilis, and MRSE. All lipopeptides showed high selectivity toward microbial strains as compared to human red blood cells (HC50 > 250 ?g/mL). Moreover, most potent lipopeptides (LP16 and LP23) did not induce drug resistance in S. aureus even after 15 rounds of passaging. In addition, a representative lipopeptide (LP16) showed tryptic stability for 24 h. These results suggest the potential of short cationic lipopeptides to boost the discovery of future antimicrobial therapeutics. PMID:23819506

Lohan, Sandeep; Cameotra, Swaranjit S; Bisht, Gopal S

2013-11-01

71

A Study of Utilization of Antimicrobial Agents in Patients on Ventilator in Intensive Care Unit (ICU) at Tertiary Care Teaching Hospital, India  

PubMed Central

Objective: To study the use of antimicrobial agents in patients on ventilator in ICU. Materials and Methods: Study was conducted at tertiary care teaching hospital Ahmedabad, India. Total 300 patients admitted in ICU and prescribed antimicrobial agents were included in the study. The data were recorded in preformed Case Record Form (CRF) and were analysed by Z and x2 Test. Results: Patients were divided into group A (patients on ventilator support) and group B (patients without ventilator support). In all the patients antimicrobial agents were prescribed empirically and more than two antimicrobial agents were prescribed in both groups. It was observed that above 60% antimicrobial agents were prescribed according to WHO, National and State Essential Medicine List (EML). Restricted antimicrobial agents (according to antimicrobial policy of tertiary care teaching hospital) were prescribed significantly (p<0.05) higher in group A as compared to group B. Resistance to antimicrobial agents by Pseudomonas aeruginosa and Kleibsella shown significantly (p<0.05) higher in group A as compared to group B. Change of antimicrobial therapy after Culture Sensitivity Test (CST) was significantly (p<0.05) higher in group A as compared to group B. Conclusion: Number of antimicrobial agents, antimicrobial resistance and change of antimicrobial therapy after CST were higher in patients on ventilator support.

Gandhi, Anuradha M; Patel, Prakruti P

2014-01-01

72

Agricultural Application of Higher Plants for Their Antimicrobial Potentials in China  

Technology Transfer Automated Retrieval System (TEKTRAN)

This chapter describes published research into Chinese medicinal and aromatic plants as sources of new crop protectants. Literature was reviewed based on our personal experience, reported antimicrobial activity against plant pathogens, novel chemical structures, and potential for agricultural utiliz...

73

Antimicrobial 14-helical beta-peptides: potent bilayer disrupting agents.  

PubMed

The interactions of two amphiphilic and cationic, nine-residue beta-peptides with liposomal membranes were studied. These beta-peptides are shown to form 14-helices in the presence of bilayers. Membrane binding and membrane permeabilization occur preferentially in the presence of anionic lipids. The beta-peptides have the ability to cause tranbilayer diffusion of phospholipids, form pores, and promote lipid mixing between liposomes. These beta-peptides have previously been shown to display antimicrobial activity comparable to that of a longer beta-peptide, beta-17, which adopts a different type of helical conformation (12-helix), and to the 23 amino acid (Ala(8,13,18))-magainin-II-amide, which adopts an alpha-helical conformation. In addition, these 14-helical beta-peptides show relatively low hemolytic activity. The biological potency and microbial specificity of the 14-helical beta-peptides, despite their relatively short length, suggests that 14-helices can be particularly disruptive to microbial membranes. PMID:15260496

Epand, Raquel F; Raguse, Tami L; Gellman, Samuel H; Epand, Richard M

2004-07-27

74

Resistance of gram-negative bacilli as related to hospital use of antimicrobial agents.  

PubMed Central

The development of resistance of gram-negative bacilli, which are common nosocomial pathogens, is an increasing problem. It is generally accepted that this resistance may directly reflect the frequency of use of various antimicrobial agents. Because our institution experienced in 1976 a dramatic change in the pattern of antimicrobial use, primarily a marked decrease in prescribing cephalosporins, we attempted to evaluate retrospectively the effects of this change upon the resistance of gram-negative bacilli that are common nosocomial pathogens. Susceptibilities of Klebsiella and Providencia spp., Pseudomonas aeruginosa, and Serratia marcescens were determined for the years 1975 to 1979. Not unexpectedly, we observed a substantial decrease in cephalosporin resistance. An unexpected finding was a decrease in aminoglycoside resistance, despite increased use of these agents. The possibility that decreased cephalosporin use may lead to decreased aminoglycoside resistance is an intriguing and provocative thesis which can only be speculative at this time but which would seem worthy of additional formal investigation. PMID:6638994

Ma, M Y; Goldstein, E J; Friedman, M H; Anderson, M S; Mulligan, M E

1983-01-01

75

Pharmacokinetic\\/pharmacodynamic profile for tigecycline—a new glycylcycline antimicrobial agent  

Microsoft Academic Search

Tigecycline is a new first-in-class glycylcycline antimicrobial agent with expanded broad-spectrum activity against both Gram-negative and Gram-positive aerobes and anaerobes, as well as atypical bacterial species. The spectrum of activity extends to clinically relevant susceptible and multidrug-resistant strains of Staphylococcus aureus, Streptococcus pneumoniae, vancomycin-resistant enterococci, and Enterobacteriaceae, including extended-spectrum ?-lactamase–producing strains. Tigecycline is administered as an intravenous formulation and has

Alison K. Meagher; Paul G. Ambrose; Thaddeus H. Grasela; Evelyn J. Ellis-Grosse

2005-01-01

76

Enterotoxin production and resistance to antimicrobial agents in porcine and bovine Escherichia coli strains.  

PubMed

A select group of porcine and bovine Escherichia coli strains capable of causing diarrheal disease in neonatal pigs and calves, respectively, were tested for enterotoxin production and resistance to 23 different antimicrobial agents. Thirty-four of the 39 porcine strains tested were enterotoxigenic; that is, they synthesized heat-stable (ST), together with heat-labile (LT), enterotoxin; ST toxin alone, or LT toxin alone. Fourteen of the 15 bovine strains tested produced ST toxin only, whereas 1 strain elaborated LT toxin only. All of the strains were multiple drug resistant. Among the porcine strains, 2 were resistant to 6 of the antimicrobial agents, and 1 was resistant to 18 of the drugs. All of these strains were resistant to cloxacillin, lincomycin, and penicillin G. None of them was resistant to chloramphenicol, colistin, gentamicin, polymyxin B, or nalidixic acid. One of the bovine strains was resistant to 7 of the drugs, and 1 strain was resistant to 17 of these antimicrobial agents. All of the bovine strains exhibited resistance to cloxacillin, lincomycin, novobiocin, pencillin G, sulfathiazole, sulfamethizole, and triple sulfa (sulfadiazine, sulfamerazine, and sulfamethazine). None of these strains showed resistance to gentamicin, nalidixic acid, nitrofurazone, or nitrofurantoin. PMID:7049021

de Lopez, A G; Kadis, S; Shotts, E B

1982-07-01

77

Effect of electrical current on the activities of antimicrobial agents against Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis biofilms.  

PubMed

Bacterial biofilms are resistant to conventional antimicrobial agents. Prior in vitro studies have shown that electrical current (EC) enhances the activities of aminoglycosides, quinolones, and oxytetracycline against Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus epidermidis, Escherichia coli, and Streptococcus gordonii. This phenomenon, known as the bioelectric effect, has been only partially defined. The purpose of this work was to study the in vitro bioelectric effect on the activities of 11 antimicrobial agents representing a variety of different classes against P. aeruginosa, methicillin-resistant Staphylococcus aureus (MRSA), and S. epidermidis. An eight-channel current generator/controller and eight chambers delivering a continuous flow of fresh medium with or without antimicrobial agents and/or EC to biofilm-coated coupons were used. No significant decreases in the numbers of log(10) CFU/cm(2) were seen after exposure to antimicrobial agents alone, with the exception of a 4.57-log-unit reduction for S. epidermidis and trimethoprim-sulfamethoxazole. We detected a statistically significant bioelectric effect when vancomycin plus 2,000 microamperes EC were used against MRSA biofilms (P = 0.04) and when daptomycin and erythromycin were used in combination with 200 or 2,000 microamperes EC against S. epidermidis biofilms (P = 0.02 and 0.0004, respectively). The results of these experiments indicate that the enhancement of the activity of antimicrobial agents against biofilm organisms by EC is not a generalizable phenomenon across microorganisms and antimicrobial agents. PMID:18725436

del Pozo, Jose L; Rouse, Mark S; Mandrekar, Jayawant N; Sampedro, Marta Fernandez; Steckelberg, James M; Patel, Robin

2009-01-01

78

Effect of ionizing energy on extracts of Quillaja saponaria to be used as an antimicrobial agent on irradiated edible coating for fresh strawberries  

NASA Astrophysics Data System (ADS)

Incorporating antimicrobial compounds into edible films or coatings provides a novel way to improve the safety and shelf life of ready-to-eat foods. Diverse studies with Quillaja saponaria Mol. (popularly named quillay) extracts have demonstrated their potential as antifungal agents against phytopathogenic fungi. Crosslinking induced by ionizing radiation is an effective method for the improvement of both barrier and mechanical properties of the edible films and coatings based on milk proteins. However there are few reports about the effects of ?-radiation on plant extracts. The aim of this work was to evaluate the effect of ionizing radiation (0, 5, 10, 15, 20, 25 and 35 kGy) on extracts prepared from in vitro plants of Q. saponaria to be used as antimicrobial agent in irradiated edible coating based on calcium caseinate and whey protein isolated, and also to establish the concentration of Q. saponaria extract to be added as an antifungal agent in the coating. Gamma irradiation since 15 kGy affects negatively the antimicrobial activity and metabolites composition of extract of Q. saponaria by reducing compounds of phenolic nature. Otherwise no effect on saponins profile was observed even at higher doses. It was possible to conclude that the antifungal activity of Q. saponaria extract is mainly related to phenolic compounds content. In addition, our work also shows that to obtain an efficient antifungal protection is necessary to add a minimum concentration of 6% of the extract after the coating irradiation.

Zúñiga, G. E.; Junqueira-Gonçalves, M. P.; Pizarro, M.; Contreras, R.; Tapia, A.; Silva, S.

2012-01-01

79

Mechanisms of antiviral action of plant antimicrobials against murine norovirus.  

PubMed

Numerous plant compounds have antibacterial or antiviral properties; however, limited research has been conducted with nonenveloped viruses. The efficacies of allspice oil, lemongrass oil, and citral were evaluated against the nonenveloped murine norovirus (MNV), a human norovirus surrogate. The antiviral mechanisms of action were also examined using an RNase I protection assay, a host cell binding assay, and transmission electron microscopy. All three antimicrobials produced significant reductions (P ? 0.05) in viral infectivity within 6 h of exposure (0.90 log10 to 1.88 log10). After 24 h, the reductions were 2.74, 3.00, and 3.41 log10 for lemongrass oil, citral, and allspice oil, respectively. The antiviral effect of allspice oil was both time and concentration dependent; the effects of lemongrass oil and citral were time dependent. Based on the RNase I assay, allspice oil appeared to act directly upon the viral capsid and RNA. The capsids enlarged from ? 35 nm to up to 75 nm following treatment. MNV adsorption to host cells was not significantly affected. Alternatively, the capsid remained intact following exposure to lemongrass oil and citral, which appeared to coat the capsid, causing nonspecific and nonproductive binding to host cells that did not lead to successful infection. Such contrasting effects between allspice oil and both lemongrass oil and citral suggest that though different plant compounds may yield similar reductions in virus infectivity, the mechanisms of inactivation may be highly varied and specific to the antimicrobial. This study demonstrates the antiviral properties of allspice oil, lemongrass oil, and citral against MNV and thus indicates their potential as natural food and surface sanitizers to control noroviruses. PMID:24907316

Gilling, Damian H; Kitajima, Masaaki; Torrey, Jason R; Bright, Kelly R

2014-08-01

80

Mechanisms of Antiviral Action of Plant Antimicrobials against Murine Norovirus  

PubMed Central

Numerous plant compounds have antibacterial or antiviral properties; however, limited research has been conducted with nonenveloped viruses. The efficacies of allspice oil, lemongrass oil, and citral were evaluated against the nonenveloped murine norovirus (MNV), a human norovirus surrogate. The antiviral mechanisms of action were also examined using an RNase I protection assay, a host cell binding assay, and transmission electron microscopy. All three antimicrobials produced significant reductions (P ? 0.05) in viral infectivity within 6 h of exposure (0.90 log10 to 1.88 log10). After 24 h, the reductions were 2.74, 3.00, and 3.41 log10 for lemongrass oil, citral, and allspice oil, respectively. The antiviral effect of allspice oil was both time and concentration dependent; the effects of lemongrass oil and citral were time dependent. Based on the RNase I assay, allspice oil appeared to act directly upon the viral capsid and RNA. The capsids enlarged from ?35 nm to up to 75 nm following treatment. MNV adsorption to host cells was not significantly affected. Alternatively, the capsid remained intact following exposure to lemongrass oil and citral, which appeared to coat the capsid, causing nonspecific and nonproductive binding to host cells that did not lead to successful infection. Such contrasting effects between allspice oil and both lemongrass oil and citral suggest that though different plant compounds may yield similar reductions in virus infectivity, the mechanisms of inactivation may be highly varied and specific to the antimicrobial. This study demonstrates the antiviral properties of allspice oil, lemongrass oil, and citral against MNV and thus indicates their potential as natural food and surface sanitizers to control noroviruses. PMID:24907316

Gilling, Damian H.; Kitajima, Masaaki; Torrey, Jason R.

2014-01-01

81

Design, synthesis, and evaluation of fimbrolide-nitric oxide donor hybrids as antimicrobial agents.  

PubMed

Fimbrolides from marine algae have shown promising activity against quorum sensing (QS), a chief regulatory and communication system in bacteria controlling biofilm formation and virulence factor. Nitric oxide (NO) at sublethal concentration has also been reported to induce dispersal of bacterial biofilms and increase their susceptibility toward standard biocides and antibiotics. Therefore, the combination of QS inhibitors and NO donors has the potential to control the development of biofilm and promote their dispersion via a nonbactericidal mechanism. Inspired by these ideas, novel fimbrolide-NO donor hybrid compounds were designed and synthesized. Fimbrolide-NO hybrids 6b, 6f, and 14a were found to be particularly effective as antimicrobials compared to the nonhybrid natural fimbrolides as revealed by bioluminescent P. aeruginosa QS reporter assays and biofilm inhibition assays. Significantly, these fimbrolide-NO hybrids represent the first dual-action antimicrobial agent based on the baterial QS inhibition and NO signaling. PMID:24191659

Kutty, Samuel K; Barraud, Nicolas; Pham, Amy; Iskander, George; Rice, Scott A; Black, David StC; Kumar, Naresh

2013-12-12

82

In Vitro Synergistic Effect of Psidium guineense (Swartz) in Combination with Antimicrobial Agents against Methicillin-Resistant Staphylococcus aureus Strains  

PubMed Central

The aim of this study was to evaluate the antimicrobial activity of aqueous extract of Psidium guineense Swartz (Araçá-do-campo) and five antimicrobials (ampicillin, amoxicillin/clavulanic acid, cefoxitin, ciprofloxacin, and meropenem) against twelve strains of Staphylococcus aureus with a resistant phenotype previously determined by the disk diffusion method. Four S. aureus strains showed resistance to all antimicrobial agents tested and were selected for the study of the interaction between aqueous extract of P. guineense and antimicrobial agents, by the checkerboard method. The criteria used to evaluate the synergistic activity were defined by the fractional inhibitory concentration index (FICI). All S. aureus strains were susceptible to P. guineense as determined by the microdilution method. The combination of the P. guineense extract with the antimicrobial agents resulted in an eight-fold reduction in the MIC of these agents, which showed a FICI ranging from 0.125 to 0.5, suggesting a synergistic interaction against methicillin-resistant Staphylococcus aureus (MRSA) strains. The combination of the aqueous extract of P. guineense with cefoxitin showed the lowest FICI values. This study demonstrated that the aqueous extract of P. guineense combined with beta lactamics antimicrobials, fluoroquinolones, and carbapenems, acts synergistically by inhibiting MRSA strains. PMID:22619603

Fernandes, Tiago Gomes; de Mesquita, Amanda Rafaela Carneiro; Randau, Karina Perrelli; Franchitti, Adelisa Alves; Ximenes, Eulália Azevedo

2012-01-01

83

Effectiveness of a hydrophilic primer when different antimicrobial agents are mixed.  

PubMed

The purpose of this study was to determine whether different types of antimicrobial agents with hydrophilic primer applied to etched enamel surfaces will affect the shear bond strength (SBS) and the bracket/adhesive failure modes of metallic orthodontic brackets. Eighty noncarious human premolars were divided into four groups of 20 each. A composite resin (Transbond XT) was used to bond stainless steel brackets. Teeth in the first group were used as a control and bonded with standard procedures. For the other three groups, mixtures containing a hydrophilic primer (Transbond MIP) and one of three anti-microbial agents were prepared (Cervitec: in 1:2 ratio; chlorhexidine mouthwash and EC40 varnish in 1:1 ratio). These mixtures were applied to the etched enamel surfaces and thoroughly light cured for 20 seconds, and the brackets were bonded and light cured for 40 seconds. The SBS values of these brackets (Mpa) were recorded using a universal testing machine. Adhesive Remnant Index scores were determined after failure of the brackets. Data were analyzed using analysis of variance (ANOVA), Tukey honestly significant difference, and chi-square tests. Results of ANOVA revealed statistically significant differences in bond strengths among the various groups tested (P < .05). The bond strength values in these four groups compared favorably with those from other studies and the minimal bond strength values that are clinically acceptable. However, results of this study demonstrated that groups 1 (control) and 2 (Cervitec varnish) had higher SBS values than the other applications. Application of different antimicrobial agents may result in differences in the site of failure. PMID:15264657

Karaman, Ali Ihya; Uysal, Tancan

2004-06-01

84

In vitro susceptibility of European human Borrelia burgdorferi sensu stricto strains to antimicrobial agents.  

PubMed

Broth microdilution and macrodilution assays were used to determine minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of six antimicrobial agents (ceftriaxone, cefuroxime sodium, azithromycin, amoxicillin, doxycycline and amikacin) for nine European human isolates of Borrelia burgdorferi sensu stricto (s.s.). Strains were obtained from patients diagnosed with Lyme borreliosis in Slovenia. Modified Kelly-Pettenkofer medium with a final inoculum of 10? Borrelia cells/mL and incubation periods of 72 h and of 3 weeks and 6 weeks were used in the determination of MICs and MBCs, respectively. Observed MICs indicated that all isolates were susceptible to all the tested antimicrobial agents with the exception of amikacin. Cefuroxime sodium (MIC??=0.063 mg/L), azithromycin (MIC??=0.22 mg/L) and ceftriaxone (MIC??=0.25 mg/L) displayed the lowest MICs, followed by amoxicillin (MIC??=1 mg/L) and doxycycline (MIC??=2 mg/L); no strain was susceptible to amikacin (MIC??=256 mg/L). MBCs after incubation for 3 weeks and 6 weeks were determined for amoxicillin (MBC??=32 mg/L), doxycycline (MBC??)=32 mg/L) and amikacin (MBC??=1024 mg/L) and were found to be high (but not defined) for azithromycin (MBC??>0.88 mg/L), cefuroxime sodium (MBC??>4 mg/L) and ceftriaxone (MBC??>4 mg/L). In determination of borrelial susceptibility to antimicrobial agents, intrinsic low susceptibility or methodological factors could result in low in vitro susceptibility of individual strains. This study is the first report on the antibiotic susceptibility of a series of European human isolates of B. burgdorferi s.s. PMID:23312603

Veinovi?, Gorana; Cerar, Tjaša; Strle, Franc; Lotri?-Furlan, Stanka; Maraspin, Vera; Cimperman, Jože; Ruži?-Sablji?, Eva

2013-03-01

85

Survey of in vitro susceptibilities of Vibrio cholerae O1 and O139 to antimicrobial agents.  

PubMed Central

Vibrio cholerae O139 (173 strains) and O1 (221 strains) were tested for their in vitro susceptibilities to 39 antimicrobial agents. Both O139 and O1 strains were highly susceptible to azithromycin, cephems, minocycline, penems, and newer fluoroquinolones. O139 strains (94.8%), O1 Indian El Tor strains (97%), and Bangladeshi El Tor strains (50%) were highly resistant to streptomycin, sulfamethoxazole, and trimethoprim and moderately resistant to chloramphenicol and furazolidone, in sharp contrast to O1 Peruvian El Tor and O1 classical strains. Some Bangladeshi El Tor strains (43.3%) showed tetracycline resistance as well. PMID:7695314

Yamamoto, T; Nair, G B; Albert, M J; Parodi, C C; Takeda, Y

1995-01-01

86

pH and Antimicrobial Activity of Portland Cement Associated with Different Radiopacifying Agents.  

PubMed

Objective. The aim of this study was to evaluate the antimicrobial activity and pH changes induced by Portland cement (PC) alone and in association with radiopacifiers. Methods. The materials tested were pure PC, PC + bismuth oxide, PC + zirconium oxide, PC + calcium tungstate, and zinc oxide and eugenol cement (ZOE). Antimicrobial activity was evaluated by agar diffusion test using the following strains: Micrococcus luteus, Streptococcus mutans, Enterococcus faecalis, Pseudomonas aeruginosa, and Candida albicans. After 24 hours of incubation at 37°C, inhibition of bacterial growth was observed and measured. For pH analysis, material samples (n = 10) were placed in polyethylene tubes and immersed in 10?mL of distilled water. After 12, 24, 48, and 72 hours, the pH of the solutions was determined using a pH meter. Results. All microbial species were inhibited by the cements evaluated. All materials composed of PC with radiopacifying agents promoted pH increase similar to pure Portland cement. ZOE had the lowest pH values throughout all experimental periods. Conclusions. All Portland cement-based materials with the addition of different radiopacifiers (bismuth oxide, calcium tungstate, and zirconium oxide) presented antimicrobial activity and pH similar to pure Portland cement. PMID:23119173

Guerreiro-Tanomaru, Juliane Maria; Cornélio, Ana Lívia G; Andolfatto, Carolina; Salles, Loise P; Tanomaru-Filho, Mário

2012-01-01

87

pH and Antimicrobial Activity of Portland Cement Associated with Different Radiopacifying Agents  

PubMed Central

Objective. The aim of this study was to evaluate the antimicrobial activity and pH changes induced by Portland cement (PC) alone and in association with radiopacifiers. Methods. The materials tested were pure PC, PC + bismuth oxide, PC + zirconium oxide, PC + calcium tungstate, and zinc oxide and eugenol cement (ZOE). Antimicrobial activity was evaluated by agar diffusion test using the following strains: Micrococcus luteus, Streptococcus mutans, Enterococcus faecalis, Pseudomonas aeruginosa, and Candida albicans. After 24 hours of incubation at 37°C, inhibition of bacterial growth was observed and measured. For pH analysis, material samples (n = 10) were placed in polyethylene tubes and immersed in 10?mL of distilled water. After 12, 24, 48, and 72 hours, the pH of the solutions was determined using a pH meter. Results. All microbial species were inhibited by the cements evaluated. All materials composed of PC with radiopacifying agents promoted pH increase similar to pure Portland cement. ZOE had the lowest pH values throughout all experimental periods. Conclusions. All Portland cement-based materials with the addition of different radiopacifiers (bismuth oxide, calcium tungstate, and zirconium oxide) presented antimicrobial activity and pH similar to pure Portland cement. PMID:23119173

Guerreiro-Tanomaru, Juliane Maria; Cornélio, Ana Lívia G.; Andolfatto, Carolina; Salles, Loise P.; Tanomaru-Filho, Mário

2012-01-01

88

Prevalence, enumeration, and antimicrobial agent resistance of Clostridium difficile in cattle at harvest in the United States.  

PubMed

To assess the potential for food contamination with Clostridium difficile from food animals, we conducted a cross-sectional fecal prevalence study in 944 randomly selected cattle harvested at seven commercial meat processing plants, representing four distant regions (median distance of 1,500 km) of the United States. In all, 944 animals were sampled in the summer of 2008. C. difficile was isolated from 1.8% (17 of 944) of cattle, with median fecal shedding concentration of 2.2 log CFU/g (range = 1.6 to 4.8, 95% confidence interval = 1.6, 4.3). Toxigenic C. difficile isolates were recovered from only four (0.4%) cattle. One of these isolates was emerging PCR ribotype 078/toxinotype V. The remaining toxigenic isolates were toxinotype 0, one of which was an isolate with resistance to linezolid, clindamycin, and moxifloxacin (by the E-test). All isolates were susceptible to vancomycin, metronidazole, and tigecycline, but the MICs against linezolid were as high as the highest reported values for human-derived isolates. The source of the linezolid-clindamycin-moxifloxacin resistance in a toxigenic C. difficile isolate from cattle is uncertain. However, since the use of these three antimicrobial agents in cattle is not allowed in North America, it is possible that resistance originated from an environmental source, from other species where those antimicrobial agents are used, or transferred from other intestinal bacteria. This study confirms that commercial cattle can carry epidemiologically relevant C. difficile strains at the time of harvest, but the prevalence at the time they enter the food chain is low. PMID:22004807

Rodriguez-Palacios, Alexander; Koohmaraie, Mohammad; LeJeune, Jeffrey T

2011-10-01

89

Antimicrobial and Antioxidant Activities of Plants from Northeast of Mexico  

PubMed Central

Traditional medicine has a key role in health care worldwide. Obtaining scientific information about the efficacy and safety of the plants from our region is one of the goals of our research group. In this report, 17 plants were selected and collected in different localities from northeast Mexico. The dried plants were separated into leaves, flowers, fruit, stems, roots and bark. Each part was extracted with methanol, and 39 crude extracts were prepared. The extracts were tested for their antimicrobial activity using three Gram-negative bacterial strains (Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii), three Gram-positive bacterial strains (Enterococcus faecalis and two Staphylococcus aureus strains), and seven clinically isolated yeasts (Candida albicans, C. krusei, C. tropicalis, C. parapsilosis and C. glabrata); their antioxidant activity was tested using a DPPH free radical assay. No activity against Gram-negative bacteria was observed with any extract up to the maximum concentration tested, 1000??g?ml?1. We report here for the first time activity of Ceanothus coeruleus against S. aureus (flowers, minimal inhibitory concentration (MIC) 125??g?ml?1), C. glabrata (MICs 31.25??g?ml?1) and C. parapsilosis (MICs between 31.25 and 125??g?ml?1); Chrysanctinia mexicana against C. glabrata (MICs 31.25 ?g ml?1); Colubrina greggii against E. faecalis (MICs 250??g?ml?1) and Cordia boissieri against C. glabrata (MIC 125 ?g ml?1). Furthermore, this is the first report about antioxidant activity of extracts from Ceanothus coeruleus, Chrysanctinia mexicana, Colubrina greggii and Cyperus alternifolius. Some correlation could exist between antioxidant activity and antiyeast activity against yeasts in the species Ceanothus coeruleus, Schinus molle, Colubrina greggii and Cordia boissieri. PMID:19770266

Salazar-Aranda, Ricardo; Pérez-López, Luis Alejandro; López-Arroyo, Joel; Alanís-Garza, Blanca Alicia; Waksman de Torres, Noemí

2011-01-01

90

Preliminary results of a survey of the use of antimicrobial agents as prophylaxis in orthopedic surgery.  

PubMed

An epidemiological survey of the use of antimicrobial prophylaxis in Italian hospitals was carried out under the auspices of the Journal of Chemotherapy. Out of 500 Italian orthopedic centers queried, 225 agreed to participate in this study. A total of 136,321 surgical procedures were reported in the 166 centers reporting complete answers on type of surgery. They comprised hip and knee prosthesis (13.9%), spine surgery (4%), hip endoprosthesis (5.2%), osteosynthesis (26.9%), arthroscopy (24.4%), and others (25.5%). Perioperative antimicrobial prophylaxis was used in 75% of operations (ranging from 57.1% to 99.4% in arthroscopy and joint prosthesis, respectively). Short term (<24 h) antimicrobial prophylaxis was performed in 38.4% of the 206 centers answering this question correctly. 61.1% of centers employed single agent prophylaxis and 70.8% of these prescriptions were betalactam antibiotics. Bacteriological analysis revealed gram-positive isolates in 73.3% of cases. Methicillin resistance was present in 45% of 915 tested strains. Out of 4221 patients with high risk of infectious complications (joint prosthesis surgery) given antimicrobial prophylaxis in 46 centers, the percentage of surgical wound infections was overall 2.1%, while that of non-surgical wound infections was 3.6%. The total infection rate was decreased by about half in association with long-term (>24 h) as compared to short-term (<24 h) antibiotic treatment (3.7% vs 7.6%, respectively), and with use of antibiotic drug combinations vs single antibiotic drugs (3.9 vs 6.6%, respectively). The incidence of surgical-site infection was not decreased by extending the chemoprophylaxis for more than the first 24 h after surgery, while it was reduced from 2.5 to 1.4% by use of combination antibiotic therapy. PMID:11936384

Mini, E; Grassi, F; Cherubino, P; Nobili, S; Periti, P

2001-11-01

91

Natural roles of antimicrobial peptides in microbes, plants and animals  

Microsoft Academic Search

Antimicrobial peptides (AMPs) are ribosomally synthesized natural antibiotics that are crucial effectors of innate immune systems in all living organisms. AMPs are diverse peptides, differing in their amino acid composition and structure, that generally display rapid killing and broad-spectrum antimicrobial activities. Therefore, AMPs have high potential for therapeutic use in healthcare and agriculture. This review focuses on in vivo studies

Gergely Maróti; Attila Kereszt; Éva Kondorosi; Peter Mergaert

2011-01-01

92

Dequalinium, a topical antimicrobial agent, displays anticarcinoma activity based on selective mitochondrial accumulation.  

PubMed Central

Positively charged lipophilic compounds, such as rhodamine 123, localize in mitochondria and are selectively accumulated and retained by carcinoma cells. It has been suggested that this phenotype may be exploited for selective killing of carcinoma cells by lipophilic cations. Here we report that doubly positively charged dequalinium, which has been used for 30 years as an antimicrobial agent in over-the-counter mouthwashes, lozenges, ointments, and paints, exhibits significant anticarcinoma activity. Dequalinium is more effective than seven of eight established anticancer drugs in prolonging the survival of mice with intraperitoneally implanted mouse bladder carcinoma MB49. Dequalinium also inhibits the growth of subcutaneously implanted human colon carcinoma CX-1 in nude mice and recurrent rat colon carcinoma W163 in rats. Lipophilic cationic compounds, such as dequalinium, could comprise a unique class of anticarcinoma agents. Images PMID:3474661

Weiss, M J; Wong, J R; Ha, C S; Bleday, R; Salem, R R; Steele, G D; Chen, L B

1987-01-01

93

In vitro susceptibility of bovine digital dermatitis associated spirochaetes to antimicrobial agents.  

PubMed

Bovine digital dermatitis (BDD) is an infectious lameness in cattle, which has a large global impact in terms of animal welfare and cost. The majority of evidence suggests that spirochaetes are the aetiological agent of this disease. The aim of this study was to identify the susceptibility of BDD associated spirochaetes to a range of antimicrobial agents with a view to potential usage in vivo to treat this widespread cattle disease. A microdilution method was adapted to determine the in vitro susceptibilities of 19 UK digital dermatitis spirochaetes (6 Treponema medium/Treponema vincentii-like, 8 Treponema phagedenis-like and 5 Treponema denticola/Treponema putidum-like) to eight relevant antimicrobials. The BDD spirochaetes exhibited the highest susceptibility to penicillin and erythromycin and this information may now be used to aid development of efficacious treatments. This study has also identified that BDD spirochaete T167 is spectinomycin resistant and that the likely biological basis is a point mutation in the 16S rRNA gene. Interestingly, nearly all Brachyspira isolate 16S rRNA gene sequences in Genbank have this substitution, suggesting it may be responsible for the characteristic spectinomycin resistance reported for the Brachyspira genus. PMID:19081208

Evans, Nicholas J; Brown, Jennifer M; Demirkan, Ibrahim; Birtles, Richard; Hart, C Anthony; Carter, Stuart D

2009-04-14

94

Standardised in vitro susceptibility testing of Borrelia burgdorferi against well-known and newly developed antimicrobial agents — Possible implications for new therapeutic approaches to Lyme disease  

Microsoft Academic Search

Lyme disease represents a disorder of potentially chronic proportions, and relatively little is known about the in vivo pharmacodynamic interactions of antimicrobial agents with borreliae. So far, evidence-based drug regimens for the effective treatment of Lyme disease have not been definitively established. Moreover, therapeutic failures have been reported for almost every suitable antimicrobial agent currently available. Resistance to treatment and

Klaus-Peter Hunfeld; Peter Kraiczy; Elena Kekoukh; Volker Schäfer; Volker Brade

2002-01-01

95

Minimum Inhibitory Concentrations for Selected Antimicrobial Agents Against Organisms Isolated from the Mammary Glands of Dairy Heifers in New Zealand and Denmark  

Microsoft Academic Search

Minimum inhibitory concentrations were deter- mined for selected antimicrobial agents against 872 bacteria isolated from intramammary infections in heifers in New Zealand (n = 401) and Denmark (n = 471). These values were reported in micrograms per milliliters. Antimicrobial agents tested against iso- lates from New Zealand were penicillin, cloxacillin, cephapirin, ceftiofur, novobiocin, enrofloxacin, erythromycin, and pirlimycin. The minimum inhibi-

S. A. Salmon; J. L. Watts; F. M. Aarestrup; J. W. Pankey; R. J. Yancey Jr.

1998-01-01

96

Plants' Metabolites as Potential Antiobesity Agents  

PubMed Central

Obesity and obesity-related complications are on the increase both in the developed and developing world. Since existing pharmaceuticals fail to come up with long-term solutions to address this issue, there is an ever-pressing need to find and develop new drugs and alternatives. Natural products, particularly medicinal plants, are believed to harbor potential antiobesity agents that can act through various mechanisms either by preventing weight gain or promoting weight loss amongst others. The inhibition of key lipid and carbohydrate hydrolyzing and metabolizing enzymes, disruption of adipogenesis, and modulation of its factors or appetite suppression are some of the plethora of targeted approaches to probe the antiobesity potential of medicinal plants. A new technology such as metabolomics, which deals with the study of the whole metabolome, has been identified to be a promising technique to probe the progression of diseases, elucidate their pathologies, and assess the effects of natural health products on certain pathological conditions. This has been applied to drug research, bone health, and to a limited extent to obesity research. This paper thus endeavors to give an overview of those plants, which have been reported to have antiobesity effects and highlight the potential and relevance of metabolomics in obesity research. PMID:22666121

Gooda Sahib, Najla; Saari, Nazamid; Ismail, Amin; Khatib, Alfi; Mahomoodally, Fawzi; Abdul Hamid, Azizah

2012-01-01

97

Antimicrobial effect of various combinations of plant extracts  

Microsoft Academic Search

The combined extracts of corni fructus, cinnamon and Chinese chive were used to evaluate its antimicrobial activity on common foodborne micro-organisms, including bacteria, yeasts and moulds. The combined extract (8:1:1, v\\/v\\/v) showed an entire antimicrobial spectrum and outstanding inhibitory effect. The combined extract was very stable under heat treatment. The inhibitory effect of the combined extract was greater with more

Pao-Chuan Hsieh; Jeng-Leun Mau; Shu-Hui Huang

2001-01-01

98

Antibiofilm effect of plant derived antimicrobials on Listeria monocytogenes.  

PubMed

The present study investigated the efficacy of sub-inhibitory concentrations (SICs, concentrations not inhibiting bacterial growth) and bactericidal concentrations (MBCs) of four, generally recognized as safe (GRAS), plant-derived antimicrobials (PDAs) in inhibiting Listeria monocytogenes (LM) biofilm formation and inactivating mature LM biofilms, at 37, 25 and 4 °C on polystyrene plates and stainless-steel coupons. In addition, the effect of SICs of PDAs on the expression of LM genes critical for biofilm synthesis was determined by real-time quantitative PCR. The PDAs and their SICs used for inhibition of biofilm were trans-cinnamaldehyde (TC 0.50, 0.75 mM), carvacrol (CR 0.50, 0.65 mM), thymol (TY 0.33, 0.50 mM), and eugenol (EG 1.8, 2.5 mM), whereas the PDA concentrations used for inactivating mature biofilms were 5.0 and 10.0 mM (TC, CR), 3.3 and 5.0 mM (TY), 18.5 and 25.0 mM (EG). All PDAs inhibited biofilm synthesis and inactivated fully formed LM biofilms on both matrices at three temperatures tested (P < 0.05). Real-time quantitative PCR data revealed that all PDAs down-regulated critical LM biofilm-associated genes (P < 0.05). Results suggest that TC, CR, TY, and EG could potentially be used to control LM biofilms in food processing environments, although further studies under commercial settings are necessary. PMID:23764223

Upadhyay, Abhinav; Upadhyaya, Indu; Kollanoor-Johny, Anup; Venkitanarayanan, Kumar

2013-10-01

99

Antimicrobial activity of Northwestern Mexican plants against Helicobacter pylori.  

PubMed

Helicobacter pylori is the major etiologic agent of such gastric disorders as chronic active gastritis and gastric carcinoma. Over the past few years, the appearance of antibiotic-resistant bacteria has led to the development of better treatments, such as the use of natural products. This study evaluated the anti-H. pylori activity of 17 Mexican plants used mainly in the northwestern part of Mexico (Sonora) for the empirical treatment of gastrointestinal disorders. The anti-H. pylori activity of methanolic extracts of the plants was determined by using the broth microdilution method. The 50% minimum inhibitory concentrations ranged from less than 200 to 400 ?g/mL for Castella tortuosa, Amphipterygium adstringens, Ibervillea sonorae, Pscalium decompositum, Krameria erecta, Selaginella lepidophylla, Pimpinella anisum, Marrubium vulgare, Ambrosia confertiflora, and Couterea latiflora and were greater than 800??g/mL for Byophyllum pinnatum, Tecoma stans linnaeus, Kohleria deppena, Jatropha cuneata, Chenopodium ambrosoides, and Taxodium macronatum. Only Equisetum gigantum showed no activity against H. pylori. This study suggests the important role that these plants may have in the treatment of gastrointestinal disorders caused by H. pylori. The findings set the groundwork for further characterization and elucidation of the active compounds responsible for such activity. PMID:21663492

Robles-Zepeda, Ramón E; Velázquez-Contreras, Carlos A; Garibay-Escobar, Adriana; Gálvez-Ruiz, Juan C; Ruiz-Bustos, Eduardo

2011-10-01

100

Antimicrobial and Antiviral Activities of Extracts from Several Plant Species Present in Entre Ríos  

Microsoft Academic Search

The ethnobotanical background of many plants used as antiseptic present in the Province of Entre Rios (Argentina) facilitated the selection of someones pertain- ing to the vascular genres Myrcianthes pungens, Myrsine laetevirens, Tessaria integrifolia, Acanthospermum australe, Arctium minus y Polygonum punctatum. The plant extracts were tested in their antimicrobial activity through the diffusion tests against six bacterial and two fungal

Juan de Dios Muñoz

101

Chemical composition and antimicrobial activity of Citrus essences on honeybee bacterial pathogen Paenibacillus larvae , the causal agent of American foulbrood  

Microsoft Academic Search

Antimicrobial properties and chemical composition of four citrus fruit essential oils to control Paenibacillus larvae, the causal agent of American foulbrood disease (AFB) were determined. This honeybee larvae disease occurs throughout the\\u000a world and is found in many beekeeping areas of Argentina. Citrus fruit essential oils tested were those from grapefruit (Citrus paradisi), sweet orange (Citrus sinensis), mandarin (Citrus nobilis)

Sandra R. Fuselli; Susana B. García de la Rosa; Martín J. Eguaras; Rosalía Fritz

2008-01-01

102

Edible coating as carrier of antimicrobial agents to extend the shelf life of fresh-cut apples  

Technology Transfer Automated Retrieval System (TEKTRAN)

Edible coatings with antimicrobial agents can extend shelf-life of fresh-cut fruits. The effect of lemongrass, oregano oil and vanillin incorporated in apple puree-alginate edible coatings, on shelf-life of fresh-cut 'Fuji' apples, was investigated. Coated apples were packed in air filled polypropyl...

103

Use of Extract of Citrus sinensis as an antimicrobial agent for foodborne zoonotic pathogens and spoilage bacteria  

Technology Transfer Automated Retrieval System (TEKTRAN)

Foodborne pathogens remain global health problems despite concerted efforts to control the transmission of these microorganisms through food. The resurgence of drug resistant bacteria has renewed interest in developing and testing new sources of antimicrobial agents to control foodborne illness. Thi...

104

Phyllanthus wightianus Müll. Arg.: A Potential Source for Natural Antimicrobial Agents  

PubMed Central

Phyllanthus wightianus belongs to Euphorbiaceae family having ethnobotanical importance. The present study deals with validating the antimicrobial potential of solvent leaf extracts of P. wightianus. 11 human bacterial pathogens (Bacillus subtilis, Streptococcus pneumoniae, Staphylococcus epidermidis, Proteus vulgaris, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhimurium, Escherichia coli, Shigella flexneri, Proteus vulgaris, and Serratia marcescens) and 4 fungal pathogens (Candida albicans, Cryptococcus neoformans, Mucor racemosus, and Aspergillus niger) were also challenged with solvent leaf extracts usingagar well and disc diffusion methods. Further, identification of the active component present in the bioactive extract was done using GC-MS analysis. Results show that all extracts exhibited broad spectrum (6–29?mm) of antibacterial activity on most of the tested organisms. The results highlight the fact that the well in agar method was more effective than disc diffusion method. Significant antimicrobial activity was detected in methanol extract against S. pneumoniae (29?mm) with MIC and MBC values of 15.62??g/mL. GC-MS analysis revealed that 29 bioactive constituents were present in methanolic extract of P. wightianus, of which 9,12-octadecaenioic acid (peak area 22.82%; RT-23.97) and N-hexadecanoic acid (peak area 21.55% RT-21.796) are the major compounds. The findings of this study show that P. wightianus extracts may be used as an anti-infective agent in folklore medicine. PMID:24883301

Natarajan, D.; Srinivasan, R.; Shivakumar, M. S.

2014-01-01

105

Antimicrobial agent exposure and the emergence and spread of resistant microorganisms: issues associated with study design.  

PubMed

Antibiotics are essential agents that have greatly reduced human mortality due to infectious diseases. Their use, and sometimes overuse, have increased over the past several decades in humans, veterinary medicine and agriculture. However, the emergence of resistant pathogens is becoming an increasing problem that could result in the re-emergence of infectious diseases. Antibiotic prescription in human medicine plays a key role in this phenomenon. Under selection pressure, resistance can emerge in the commensal flora of treated individuals and disseminate to others. However, even if the effects of antimicrobial use on resistance is intuitively accepted, scientific rationales are required to convince physicians, legislators and public opinion to adopt appropriate behaviours and policies. With this review, we aim to provide an overview of different epidemiological study designs that are used to study the relationship between antibiotic use and the emergence and spread of resistance, as well as highlight their main strengths and weaknesses. PMID:23268203

Angebault, C; Andremont, A

2013-05-01

106

Susceptibility of clinical isolates of Campylobacter pyloridis to 11 antimicrobial agents.  

PubMed Central

The activities of 11 antimicrobial agents, including two bismuth salts, against 70 strains of Campylobacter pyloridis isolated from gastric biopsy specimens were tested. The isolates were very susceptible to penicillin (the MIC for 90% of the strains tested [MIC90] was 0.03 microgram/ml), erythromycin, cefoxitin (MIC90, 0.12 microgram/ml), gentamicin, and ciprofloxacin (MIC90, 0.25 microgram/ml). The bismuth salts and nalidixic acid had moderate activity (MIC90, 16 to 64 micrograms/ml). Twenty percent of the isolates were resistant to metronidazole (MIC, greater than 1 micrograms/ml), and all were resistant to sulfamethoxazole and trimethoprim (MIC90, greater than 256 micrograms/ml). PMID:2935076

McNulty, C A; Dent, J; Wise, R

1985-01-01

107

In vitro activity of 10 antimicrobial agents against bacteria isolated from cows with clinical mastitis.  

PubMed

The susceptibility of 495 strains of bacteria, recently isolated in France from cows with clinical mastitis, to 10 antimicrobial agents--penicillin G, cloxacillin, oxacillin, cephalexin, cefazolin, cephapirin, cefquinome, neomycin, ampicillin and colistin--was determined by measuring their minimum inhibitory concentrations (MICS). Overall, the levels of resistance were very low except for staphylococci and penicillin G. The 167 streptococcal strains were susceptible to all of the beta-lactams tested, but six (3-6 per cent) were highly resistant to neomycin. Of the 171 staphylococcal isolates, 36.2 per cent were resistant to penicillin G, one strain of Staphylococcus sciuri was classified as methicillin-resistant, but they were all susceptible to neomycin. None of the 122 strains of Escherichia coli was resistant to colistin, but 12 had high MIC values for one or more of the cephalosporins. PMID:12723630

Guérin-Faublée, V; Carret, G; Houffschmitt, P

2003-04-12

108

Quorum sensing peptides mediating interspecies bacterial cell death as a novel class of antimicrobial agents.  

PubMed

mazEF is a toxin-antitoxin stress-induced module which is abundant on the chromosome of most bacteria including pathogens and most extensively studied in Escherichia coli. E. coli mazEF mediated cell death is a population phenomenon requiring the quorum-sensing (QS) 'Extracellular Death Factor' (EDF), the E. coli peptide NNWNN. E. coli mazEF-mediated cell death can also be triggered by different QS peptides secreted by the Gram positive bacterium Bacillus subtilis and the Gram negative bacterium Pseudomonas aeruginosa. Thus, the different EDFs belong to a family of QS peptides that mediates interspecies cell death. We suggest that members of the EDF family may become the basis for a novel class of antimicrobial agents to trigger death from outside the bacterial cells. PMID:25244032

Kumar, Sathish; Engelberg-Kulka, Hanna

2014-10-01

109

Search for antisickling agents from plants  

PubMed Central

The sickle cell disease is fatal in nature. Thousands of children are dying off due to this health problem throughout the globe. Due to the rapid development of diagnosis and clinical managements such patients are living up to a respectable age. But as there is no permanent cure the patients are suffering from bone and joint pain, jaundice, hepato-splenomegaly, chronic infections etc. The main physiological complicacy is due to the polymerization of sickle hemoglobin (HbS), (sickling process) inside the red blood cell (RBC) of these patients during deoxygenating state. The change of RBC from spherical to sickle shape is due to the polymerization of mutant hemoglobin (HbS) inside the RBC and membrane distortion during anoxic condition. The mechanism and the process of sickling are very complex and multifactor in nature. To get rid from such complicacies it is necessary to suitably and accurately stop the sickling of RBC of the patients. The potential anti-sickling agents either from natural sources and/or synthetic molecules may be helpful for reducing the clinical morbidity of the patients. A lot of natural compounds from plant extracts have been tried by several workers in recent past. Most of the studies are based on in vitro red cell sickling studies and their mode of action has not been properly understood. Although, few studies have been in vivo in nature pertaining to transgenic sickle animal model, there is paucity of data on the human studies. The result of such studies although has shown some degree of success, a promising anti-sickling agent is yet to be established. PMID:23922457

Dash, Bisnu Prasad; Archana, Y.; Satapathy, Nibarana; Naik, Soumendra Kumar

2013-01-01

110

Antimicrobial and free radical scavenging activities of five Palestinian medicinal plants.  

PubMed

Extracts from five indigenous Palestinian medicinal plants including Rosmarinus officinalis, Pisidium guajava, Punica granatum peel, grape seeds and Teucrium polium were investigated for antimicrobial and free radical scavenging activities against eight microorganisms, using well diffusion method. The microorganisms included six bacterial isolates (i.e. Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginos, Klebsiella pneumonia, Bacillus subtilis and Micrococcus luteus) and two fungal isolates (i.e. Candida albicans and Aspergillus niger). A standard antioxidant assay was performed on the plant extracts to assess their capability in scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH). Of the five tested plant extract, only Rosmarinus offcinalis extract contained significant antimicrobial activity against all eight microbial isolates including Pseudomonas aeruginosa. Extracts from other four plants exhibited a variable antimicrobial activity against all microorganisms, except Pseudomonas aeruginosa. Significant antioxidant activity was detected in all plant extracts. However, extracts from Pisidium guajava leaves contained significantly higher antioxidant activity compared to the other extracts tested. The antimicrobial and scavenging activities detected in this in vitro study in extracts from the five Palestinian medicinal plants suggest that further study is needed to identify active compounds to target diseases caused by a wide-spectrum pathogens. PMID:24146509

Qabaha, Khaled Ibraheem

2013-01-01

111

Essential oils and herbal extracts as antimicrobial agents in cosmetic emulsion.  

PubMed

The cosmetic industry adapts to the needs of consumers seeking to limit the use of preservatives and develop of preservative-free or self-preserving cosmetics, where preservatives are replaced by raw materials of plant origin. The aim of study was a comparison of the antimicrobial activity of extracts (Matricaria chamomilla, Aloe vera, Calendula officinalis) and essential oils (Lavandulla officinallis, Melaleuca alternifolia, Cinnamomum zeylanicum) with methylparaben. Extracts (2.5 %), essential oils (2.5 %) and methylparaben (0.4 %) were tested against Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213, Candida albicans ATCC 14053. Essentials oils showed higher inhibitory activity against tested microorganism strain than extracts and methylparaben. Depending on tested microorganism strain, all tested extracts and essential oils show antimicrobial activity 0.8-1.7 and 1-3.5 times stronger than methylparaben, respectively. This shows that tested extracts and essential oils could replace use of methylparaben, at the same time giving a guarantee of microbiological purity of the cosmetic under its use and storage. PMID:24426114

Herman, Anna; Herman, Andrzej Przemys?aw; Domagalska, Beata Wanda; M?ynarczyk, Andrzej

2013-06-01

112

Antimicrobial susceptibility of Lactobacillus species isolated from commercial ethanol plants  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bacterial contamination of commercial fermentation cultures is a common and costly problem to the fuel ethanol industry. Antimicrobials such as virginiamycin (VIR) and penicillin (PEN) are frequently used to control contamination but there are little data available on the susceptibility of bacteria...

113

THE POTENTIAL OF THE ENDOPHYTIC FUNGUS, MUSCODOR ALBUS, AS A BIO-CONTROL AGENT AGAINST ECONOMICALLY IMPORTANT PLANT PARASITIC NEMATODES OF VEGETABLE CROPS IN WASHINGTON STATE  

Technology Transfer Automated Retrieval System (TEKTRAN)

The fungus Muscodor albus produces a mixture of antimicrobial volatile organic chemicals with activity against post-harvest disease causing organisms, insect pests of harvested fruit and tubers, and soil-borne disease causing agents and plant parasitic nematodes. M. albus was tested for its potenti...

114

Synthesis and biological evaluation of thiazoline derivatives as new antimicrobial and anticancer agents.  

PubMed

N'-(3,4-Diarylthiazol-2(3H)-ylidene)-2-(arylthio)acetohydrazides were synthesized and evaluated for their antimicrobial activity and cytotoxicity against NIH/3T3 cells. Compound 22 bearing 1-phenyl-1H-tetrazole and p-chlorophenyl moieties was found to be the most promising antibacterial agent against Pseudomonas aeruginosa, whereas compound 23 bearing 1-phenyl-1H-tetrazole and p-bromophenyl moieties was the most promising antifungal agent against Candida albicans. The most effective derivatives were also evaluated for their cytotoxicity against C6 glioma cells. The results indicated that compound 17 bearing 1-phenyl-1H-tetrazole and nonsubstituted phenyl moieties (IC?? = 8.3 ± 2.6 ?g/mL) was more effective than cisplatin (IC?? = 13.7 ± 1.2 ?g/mL) against C6 glioma cells. Compound 17 also exhibited DNA synthesis inhibitory activity on C6 cells. Furthermore, compound 17 showed low toxicity to NIH/3T3 cells (IC?? = 416.7 ± 28.9 ?g/mL). PMID:24480358

Alt?ntop, Mehlika Dilek; Kaplanc?kl?, Zafer As?m; Ciftçi, Gül?en Akal?n; Demirel, Rasime

2014-03-01

115

Assessment of antimicrobial (host defense) peptides as anti-cancer agents.  

PubMed

Cationic antimicrobial (host defense) peptides (CAPs) are able to kill microorganisms and cancer cells, leading to their consideration as novel candidate therapeutic agents in human medicine. CAPs can physically associate with anionic membrane structures, such as those found on cancer cells, causing pore formation, intracellular disturbances, and leakage of cell contents. In contrast, normal cells are less negatively-charged and are typically not susceptible to CAP-mediated cell death. Because the interaction of CAPs with cells is based on charge properties rather than cell proliferation, both rapidly dividing and quiescent cancer cells, as well as multidrug-resistant cancer cells, are targeted by CAPs, making CAPS potentially valuable as anti-cancer agents. CAPs often exist as families of peptides with slightly different amino acid sequences. In addition, libraries of synthetic peptide variants based on naturally occurring CAP templates can be generated in order to improve upon their action. High-throughput screens are needed to quickly and efficiently assess the suitability of each CAP variant. Here we present the methods for assessing CAP-mediated cytotoxicity against cancer cells (suspension and adherent) and untransformed cells (measured using the tritiated thymidine-release or MTT assay), and for discriminating between cell death caused by necrosis (measured using lactate dehydrogenase- or (51)Cr-release assays), or apoptosis and necrosis (single-stranded DNA content measured by flow cytometry). In addition the clonogenic assay, which assesses the ability of single transformed cells to multiply and produce colonies, is described. PMID:24146403

Douglas, Susan; Hoskin, David W; Hilchie, Ashley L

2014-01-01

116

Antibiotic Resistance and Implications for the Appropriate Use of Antimicrobial Agents  

Microsoft Academic Search

\\u000a Antimicrobial resistance is a major public health threat associated with increased morbidity and mortality as well as enormous\\u000a healthcare costs that are attributed to longer hospital stays, which require multiple antimicrobial therapies. After recognizing\\u000a antimicrobial resistance as a phenomenon and the need for a response, the Institute of Medicine published a report in 1988,\\u000a Antimicrobial Resistance: Issues and Options [1].

Meredith Deutscher; Cindy Friedman

117

Antimicrobial activity of essential oils from plants against selected pathogenic and saprophytic microorganisms.  

PubMed

The beneficial health effects of extracts from many types of plants that are used as seasoning agents in foods and beverages have been claimed for centuries. The purpose of this study was to examine the effectiveness of selected herb and spice essential oils for control of growth and survival of microorganisms. Inhibition of growth was tested by the paper disc agar diffusion method. Antibiotic susceptibility discs were used as control. Minimum lethal concentration (MLC) was determined by the tube dilution method. Essential oils from anise, angelica, basil, carrot, celery, cardamom, coriander, dill weed, fennel, oregano, parsley, and rosemary were evaluated. Inhibition ranged from complete with oregano to no inhibition with carrot oil for each of the test strains that included: Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O:157:H7, Yersinia enterocolitica, Pseudomonas aeruginosa, Lactobacillus plantarum, Aspergillus niger, Geotrichum, and Rhodotorula. Oregano essential oil showed the greatest inhibition (zone, > or = 70 to 80 mm) (MLC, approximately 8 ppm). Coriander and basil were also highly inhibitory (MLC, approximately 25 to 50 ppm) to E. coli O:157:H7 and to the other bacteria and fungi tested. Anise oil was not particularly inhibitory to bacteria (inhibition zone, approximately 25 mm); however, anise oil was highly inhibitory to molds. Because some of the herbal and spice essential oils are highly inhibitory to selected pathogenic and spoilage microorganisms, they may provide alternatives and supplements to conventional antimicrobial additives in foods. PMID:11456186

Elgayyar, M; Draughon, F A; Golden, D A; Mount, J R

2001-07-01

118

Combating Pathogenic Microorganisms Using Plant-Derived Antimicrobials: A Minireview of the Mechanistic Basis  

PubMed Central

The emergence of antibiotic resistance in pathogenic bacteria has led to renewed interest in exploring the potential of plant-derived antimicrobials (PDAs) as an alternative therapeutic strategy to combat microbial infections. Historically, plant extracts have been used as a safe, effective, and natural remedy for ailments and diseases in traditional medicine. Extensive research in the last two decades has identified a plethora of PDAs with a wide spectrum of activity against a variety of fungal and bacterial pathogens causing infections in humans and animals. Active components of many plant extracts have been characterized and are commercially available; however, research delineating the mechanistic basis of their antimicrobial action is scanty. This review highlights the potential of various plant-derived compounds to control pathogenic bacteria, especially the diverse effects exerted by plant compounds on various virulence factors that are critical for pathogenicity inside the host. In addition, the potential effect of PDAs on gut microbiota is discussed. PMID:25298964

Upadhyaya, Indu; Kollanoor-Johny, Anup

2014-01-01

119

Immune mediators of sea-cucumber Holothuria tubulosa (Echinodermata) as source of novel antimicrobial and anti-staphylococcal biofilm agents  

PubMed Central

The present study aims to investigate coelomocytes, immune mediators cells in the echinoderm Holothuria tubulosa, as an unusual source of antimicrobial and antibiofilm agents. The activity of the 5kDa peptide fraction of the cytosol from H. tubulosa coelomocytes (5-HCC) was tested against a reference group of Gram-negative and Gram-positive human pathogens. Minimal inhibitory concentrations (MICs) ranging from 125 to 500 mg/ml were determined against tested strains. The observed biological activity of 5-HCC could be due to two novel peptides, identified by capillary RP-HPLC/nESI-MS/MS, which present the common chemical-physical characteristics of antimicrobial peptides. Such peptides were chemically synthesized and their antimicrobial activity was tested. The synthetic peptides showed broad-spectrum activity at 12.5 mg/ml against the majority of the tested Gram-positive and Gram-negative strains, and they were also able to inhibit biofilm formation in a significant percentage at a concentration of 3.1 mg/ml against staphylococcal and Pseudomonas aeruginosa strains. The immune mediators in H. tubulosa are a source of novel antimicrobial peptides for the development of new agents against biofilm bacterial communities that are often intrinsically resistant to conventional antibiotics. PMID:23800329

2013-01-01

120

Composition and antimicrobial activity of essential oils of some medicinal and spice plants  

Microsoft Academic Search

An examination was made on the chemical composition and antimicrobial activity of four medicinal plants Carum carvi, Coriandrum sativum, Hyssopus officinalis, and Eucalyptus globulus, the first three of which are also used as culinary spice herbs. Carum carvi L. and Coriandrum sativum L. belong to the Apiacea family. In traditional medicine, Carum carvi is used in the form of a

M. Cvijovic; D. Djukic; L. Mandic; G. Acamovic-Djokovic; M. Pesakovic

2010-01-01

121

Antimicrobial resistance of Listeria monocytogenes isolated from a poultry further processing plant  

Technology Transfer Automated Retrieval System (TEKTRAN)

The objective of this study was to compare antimicrobial resistance profiles of distinct types of Listeria monocytogenes isolated from a commercial poultry cooking plant. One hundred fifty seven L. monocytogenes isolates representing 14 different ActA types were tested for susceptibility to 19 ant...

122

Edible Apple Film Wraps Containing Plant Antimicrobials Inactivate Foodborne Pathogens on Meat and Poultry Products  

Technology Transfer Automated Retrieval System (TEKTRAN)

As part of an effort to discover new ways to improve microbial food safety, we evaluated apple-based edible films containing plant antimicrobial compounds for their activity against pathogenic foodborne bacteria on meat and poultry products. Salmonella enterica or Escherichia coli O157:H7 (107 CFU/...

123

Antimicrobials Treatment  

NASA Astrophysics Data System (ADS)

The use of antimicrobials is a common practice for preservation of foods. Incorporation, in a food recipe, of chemical antimicrobials towards inhibition of spoilage and pathogenic micro-organisms results in the compositional modification of food. This treatment is nowadays undesirable for the consumer, who likes natural products. Scientific community reflecting consumers demand for natural antimicrobials has made efforts to investigate the possibility to use natural antimicrobials such us bacteriocins and essential oils of plant origin to inhibit microbial growth.

Drosinos, Eleftherios H.; Skandamis, Panagiotis N.; Mataragas, Marios

124

The antimicrobial properties of cedar leaf (Thuja plicata) oil; a safe and efficient decontamination agent for buildings.  

PubMed

Cedar leaf oil (CLO), derived from the Western red cedar, Thuja plicata, was evaluated as a safe and acceptable broad spectrum antimicrobial agent, with a view to its potential applications in buildings, including the alleviation of sick building syndrome. Various Gram-positive and Gram-negative human bacteria, and two fungal organisms, all known to be common environmental sources of potential infection, were selected and tested quantitatively, and all of them were found to be susceptible to CLO liquid and vapor. Bacterial spores and Aspergillus niger were sensitive, although less so than the vegetative bacteria. Similar tests with cultured human lung cells showed that continuous exposure to CLO vapor for at least 60 minutes was not toxic to the cells. Based on these results, CLO shows promise as a prospective safe, green, broad-spectrum anti-microbial agent for decontamination of buildings. PMID:22408584

Hudson, James; Kuo, Michael; Vimalanathan, Selvarani

2011-12-01

125

The Antimicrobial Properties of Cedar Leaf (Thuja plicata) Oil; A Safe and Efficient Decontamination Agent for Buildings  

PubMed Central

Cedar leaf oil (CLO), derived from the Western red cedar, Thuja plicata, was evaluated as a safe and acceptable broad spectrum antimicrobial agent, with a view to its potential applications in buildings, including the alleviation of sick building syndrome. Various Gram-positive and Gram-negative human bacteria, and two fungal organisms, all known to be common environmental sources of potential infection, were selected and tested quantitatively, and all of them were found to be susceptible to CLO liquid and vapor. Bacterial spores and Aspergillus niger were sensitive, although less so than the vegetative bacteria. Similar tests with cultured human lung cells showed that continuous exposure to CLO vapor for at least 60 minutes was not toxic to the cells. Based on these results, CLO shows promise as a prospective safe, green, broad-spectrum anti-microbial agent for decontamination of buildings. PMID:22408584

Hudson, James; Kuo, Michael; Vimalanathan, Selvarani

2011-01-01

126

Biofilm formation by Propionibacterium acnes is associated with increased resistance to antimicrobial agents and increased production of putative virulence factors.  

PubMed

Propionibacterium acnes plays an important role in the pathogenesis of acne vulgaris, a common disorder of the pilosebaceous follicles. Recently, it was suggested that P. acnes cells residing within the follicles grow as a biofilm. In the present study, we tested the biofilm-forming ability of several P. acnes strains in a microtiter plate model. We also evaluated the resistance of biofilm-grown P. acnes towards antimicrobial agents commonly used in the treatment of acne and the production of putative virulence factors. Our results indicate that P. acnes can form biofilms in vitro. The results also show that sessile P. acnes cells are more resistant to various commonly used antimicrobial agents than planktonic cells. In addition, sessile cells produce more extracellular lipases as well as significant amounts of the quorum-sensing molecule autoinducer-2. PMID:17399956

Coenye, Tom; Peeters, Elke; Nelis, Hans J

2007-05-01

127

Antimicrobial activity of some coumarin containing herbal plants growing in Finland  

Microsoft Academic Search

Antimicrobial screening against selected Gram-positive and Gram-negative bacteria, yeasts, mold, as well as plant pathogenic fungi, with emphasis on method optimization was carried out on methanol extracts prepared from seven plants grown in Finland. Sensitivity to the extracts was found to vary considerably among the micro-organisms, the extract from Petroselinum crispum and Ruta graveolens showing the highest toxicity against Rhizoctonia

Tiina Ojala; Susanna Remes; Pasi Haansuu; Heikki Vuorela; Raimo Hiltunen; Kielo Haahtela; Pia Vuorela

2000-01-01

128

SOFTWARE AGENTS IN HANDLING ABNORMAL SITUATIONS IN INDUSTRIAL PLANTS  

E-print Network

SOFTWARE AGENTS IN HANDLING ABNORMAL SITUATIONS IN INDUSTRIAL PLANTS Sami Syrjälä and Seppo Kuikka Korkeakoulunkatu 10, 33101 Tampere Finland sami.syrjala@tut.fi and seppo.kuikka@tut.fi ABSTRACT Software agents have recently gained a lot of reputation in software engineering. These autonomous actors can provide

129

Synthesis and Biological Evaluation of 2-Aminobenzamide Derivatives as Antimicrobial Agents: Opening/Closing Pharmacophore Site  

PubMed Central

A series of new 2-aminobenzamide derivatives (1–10) has been synthesized in good to excellent yields by adopting both conventional and/or a time-efficient microwave assisted methodologies starting from isatoic anhydride (ISA) and characterized on the basis of their physical, spectral and microanalytical data. Selected compounds of this series were then tested against various bacterial (Bacillus subtilis (RCMB 000107) and Staphylococcus aureus (RCMB 000106). Pseudomonas aeruginosa (RCMB 000102) and Escherichia coli (RCMB 000103) and fungal strains (Saccharomyces cerevisiae (RCMB 006002), Aspergillus fumigatus (RCMB 002003) and Candida albicans (RCMB 005002) to explore their potential as antimicrobial agents. Compound 5 was found to be the most active compound among those tested, which showed excellent antifungal activity against Aspergillus fumigatus (RCMB 002003) more potent than standard Clotrimazole, and moderate to good antibacterial and antifungal activity against most of the other strains of bacteria and fungi. Furthermore, potential pharmacophore sites were identified and their activity was related with the structures in the solution. PMID:24663060

Mabkhot, Yahia N.; Al-Majid, Abdullah M.; Barakat, Assem; Al-Showiman, Salim S.; Al-Har, Munirah S.; Radi, Smaail; Naseer, Muhammad Moazzam; Hadda, Taibi B.

2014-01-01

130

Oxidative degradation study on antimicrobial agent ciprofloxacin by electro-fenton process: Kinetics and oxidation products.  

PubMed

Oxidative degradation of the antimicrobial agent ciprofloxacin hydrochloride (CIP) has been investigated using electro-Fenton (EF) treatment with a constant current in the range 60-500mA. The process generates highly oxidant species OH in situ via electrochemically monitored Fenton reaction. The EF experiments were performed using cells with a carbon felt cathode and Pt anode. Effect of applied current and catalyst concentration on the kinetics of oxidative degradation and mineralization efficiency have been investigated. Degradation of CIP followed pseudo-first order reaction kinetics. The rate constant of the oxidation of CIP by OH has been determined to be (1.01±0.14) × 10(10) M(-1) s(-1) by using competitive kinetics method. An optimum current of 400mA and a catalyst concentration of Fe(2+) at 0.1mM are found to be optimal for an effective degradation of CIP under our operating conditions. A remarkably high degree of mineralization (>94%) was obtained at 6h of treatment under these conditions. A number of stable intermediate products have been identified using HPLC and LC-MS/MS analyses. Based on the identified reaction intermediates, a plausible reaction pathway was proposed for the mineralization process. The high degree of mineralization obtained in this work highlights the potential application of EF process in the efficient removal of fluoroquinolone based drugs in aqueous medium. PMID:25201488

Yahya, Muna Sh; Oturan, Nihal; El Kacemi, Kacem; El Karbane, Miloud; Aravindakumar, C T; Oturan, Mehmet A

2014-12-01

131

Antimicrobial and Cytotoxic Activity of Three Bitter Plants Enhydra Fluctuans, Andrographis Peniculata and Clerodendrum Viscosum.  

PubMed Central

Purpose: In this study, three important medicinal plants (Enhydra fluctuans Lour, Clerodendrum viscosum Vent and Andrographis peniculata Wall) of Bangladesh were investigated to analyze their antimicrobial and cytotoxic activities against some pathogenic microorganisms and Artemia salina (brine shrimp nauplii). Methods: The coarse powder material of leaves of each plant was extracted separately with methanol and acetone to yield methanol extracts of leaves of Enhydra fluctuans (MLE), Clerodendrum viscosum (MLC) and Andrographis peniculata (MLA), and acetone extracts of leaves of Enhydra fluctuans (ALE), Clerodendrum viscosum (ALC) and Andrographis peniculata (ALA). The disc diffusion method and the method described by Meyer were used to determine the antimicrobial and cytotoxic activities of each plant extract. Results: Among the test samples, MLE and ALE showed comparatively better antimicrobial activity against a number of bacteria and fungi with inhibition zones in the range of 06-15 mm and according to the intensity of activity, the efficacy against microorganisms were found in the order of Enhydra fluctuans > Andrographis peniculata > Clerodendrum viscosum. In cytotoxicity assay, all samples were found to be active against brine shrimp nauplii (Artemia salina) and ALA produced lowest LC50 value (7.03 ?g/ml). Conclusion: Enhydra fluctuans and Andrographis peniculata possesses significant antimicrobial and cytotoxic activities. PMID:24312795

Amin, M. Ruhul; Mondol, Ripon; Habib, M. Rowshanul; Hossain, M. Tofazzal

2012-01-01

132

The continuing search for antitumor agents from higher plants  

PubMed Central

Plant secondary metabolites and their semi-synthetic derivatives continue to play an important role in anticancer drug therapy. In this short review, selected single chemical entity antineoplastic agents from higher plants that are currently in clinical trials as cancer chemotherapy drug candidates are described. These compounds are representative of a wide structural diversity. In addition, the approaches taken toward the discovery of anticancer agents from tropical plants in the laboratory of the authors are summarized. The successful clinical utilization of cancer chemotherapeutic agents from higher plants has been evident for about half a century, and, when considered with the promising pipeline of new plant-derived compounds now in clinical trials, this augurs well for the continuation of drug discovery research efforts to elucidate additional candidate substances of this type. PMID:20228943

Pan, Li; Chai, Heebyung; Kinghorn, A. Douglas

2009-01-01

133

The use of versatile plant antimicrobial peptides in agribusiness and human health.  

PubMed

Plant immune responses involve a wide diversity of physiological reactions that are induced by the recognition of pathogens, such as hypersensitive responses, cell wall modifications, and the synthesis of antimicrobial molecules including antimicrobial peptides (AMPs). These proteinaceous molecules have been widely studied, presenting peculiar characteristics such as conserved domains and a conserved disulfide bond pattern. Currently, many AMP classes with diverse modes of action are known, having been isolated from a large number of organisms. Plant AMPs comprise an interesting source of studies nowadays, and among these there are reports of different classes, including defensins, albumins, cyclotides, snakins and several others. These peptides have been widely used in works that pursue human disease control, including nosocomial infections, as well as for agricultural purposes. In this context, this review will focus on the relevance of the structural-function relations of AMPs derived from plants and their proper use in applications for human health and agribusiness. PMID:24548568

de Souza Cândido, Elizabete; e Silva Cardoso, Marlon Henrique; Sousa, Daniel Amaro; Viana, Juliane Cançado; de Oliveira-Júnior, Nelson Gomes; Miranda, Vívian; Franco, Octávio Luiz

2014-05-01

134

Rhamnolipids as emulsifying agents for essential oil formulations: Antimicrobial effect against Candidaalbicans and methicillin-resistant Staphylococcus aureus.  

PubMed

This work examines the influence of essential oil composition on emulsification with rhamnolipids and their use as therapeutic antimicrobial agents against two opportunistic pathogens, methicillin-resistant Staphylococcus aureus (MRSA) and Candida albicans. Rhamnolipids, produced by Pseudomonas aeruginosa, with waste frying oil as the carbon source, were composed of eight rhamnolipid homologues. The rhamnolipid mixture was used to produce emulsions containing essential oils (EOs) of Melaleuca alternifolia, Cinnamomum verum, Origanum compactum and Lavandula angustifolia using the titration method. Ternary phase diagrams were designed to evaluate emulsion stability, which differed depending on the essential oil. The in vitro antimicrobial activity of the EOs alone and the emulsions was evaluated. The antimicrobial activity presented by the essential oils alone increased with emulsification. The surface properties of rhamnolipids contribute to the positive dispersion of EOs and thus increase their availability and antimicrobial activity against C. albicans and S. aureus. Therefore, rhamnolipid-based emulsions represent a promising approach to the development of EO delivery systems. PMID:25269010

Haba, Ester; Bouhdid, Samira; Torrego-Solana, Noelia; Marqués, A M; Espuny, M José; García-Celma, M José; Manresa, Angeles

2014-09-28

135

The comparative effect of novel Pelargonium essential oils and their corresponding hydrosols as antimicrobial agents in a model food system.  

PubMed

Essential oils and their corresponding hydrosols, obtained after distillation of various scented Pelargonium (Geraniaceae) leaves were assessed for their antimicrobial activity in a model food system. Both the essential oils and hydrosols were used at 1000 ppm in broccoli soup, previously inoculated with Enterobacter aerogenes (at 10(5) cfu g(-1)) and Staphylococcus aureus (at 10(4) cfu g(-1)). The results showed a complete inhibition of S. aureus in the broccoli soup by the essential oils of 'Sweet Mimosa', 'Mabel Grey', P. graveolens, 'Atomic Snowflake', 'Royal Oak', 'Attar of Roses' and a lesser effect by 'Chocolate Peppermint' and 'Clorinda'; the hydrosols, however, had a potentiating effect on the bacterial population in the food. Both extracts showed a complete inhibition of S. aureus in the Maximum Recovery Diluent (MRD). Antibacterial activity against E. aerogenes in the broccoli soup was generally very much reduced: only the essential oil of 'Mabel Grey' showed complete inhibition and virtually no reductions in colonies were seen with the other essential oils; the hydrosols again caused an increase in bacterial colonies. All the essential oils, bar Chocolate Peppermint showed complete inhibition of E. aerogenes in MRD, but the hydrosols showed no effect. The results strongly suggest that the residual hydrosols from distillation of these plant essential oils have no potential as antibacterial agents in foods, in contrast to most of the essential oils, which show potential against some micro-organisms, but only in some food systems. The problem of food component interference and its possible management is discussed. PMID:12557249

Lis-Balchin, M; Steyrl, H; Krenn, E

2003-01-01

136

A close look at alcohol gel as an antimicrobial sanitizing agent  

Microsoft Academic Search

Background: Hand transmission of microbes by health care workers is a primary cause of nosocomial infections in both long-term and acute care facilities. Compliance with effective handwashing and hand sanitization regimens can break this cycle. Methods: We investigated the antimicrobial efficacy and irritation potential of 5 handwash product regimens: a nonantimicrobial lotion soap, an antimicrobial lotion soap, an alcohol gel

Daryl S. Paulson; Eleanor J. Fendler; Michael J. Dolan; Ronald A. Williams

1999-01-01

137

In vitro susceptibility of Mycoplasma hyosynoviae and M. hyorhinis to antimicrobial agents.  

PubMed

Fifty-four Japanese strains of Mycoplasma hyosynoviae isolated from porkers during 1980 to 1995, and 107 Japanese strains of M. hyorhinis isolated from piglets with respiratory disease during 1991 to 1994 were investigated for the in vitro activities of 13 antimicrobial agents [josamycin, tylosin, spiramycin, kitasamycin, erythromycin, lincomycin (LCM), kanamycin (KM), chloramphenicol (CP), thiamphenicol (TP), tiamulin (TML), oxytetracycline (OTC), chlortetracycline (CTC), and enrofloxacin (ERFX)] by the agar dilution method. Of the drugs tested TML showed the highest activity with minimum inhibitory concentration (MIC) of 0.013 to 0.1 microgram/ m/ (MIC90; 0.05 microgram/ml) against strains of M. hyosynoviae, and 0.2 to 0.78 microgram/ml (MIC90; 0.39 microgram/ml) against strains of M. hyorhinis. ERFX, LCM, most of the 16-membered macrolide antibiotics and tetracyclines also showed low MICs against both mycoplasma species. The susceptibility of KM, CP and TP to the mycoplasmas was considered to be of a secondary grade. Two of 54 strains of M. hyosynoviae, and 11 of 107 strains of M. hyorhinis showed resistance to all 14- and 16-membered macrolide antibiotics tested. Tetracyclines (OTC and CTC) showed a relatively broad MIC distribution from 0.1 to 6.25 micrograms/ml against the M. hyosynoviae strains tested. All of the strains isolated during 1980 to 1984 were susceptible at the concentration of 0.78 microgram/ml or less (MIC90; 0.78 microgram/ml) to OTC and 1.56 micrograms/ml or less (MIC90; 1.56 micrograms/ml) to CTC, while the susceptibility of strains isolated recently, during 1994 to 1995, was more than 0.78 microgram/ml (MIC90; 3.13 micrograms/ml) to OTC, and more than 1.56 micrograms/ml (MIC90; 6.25 micrograms/ml) to CTC. PMID:8959659

Kobayashi, H; Sonmez, N; Morozumi, T; Mitani, K; Ito, N; Shiono, H; Yamamoto, K

1996-11-01

138

Determination of Mycoplasma bovis susceptibilities against six antimicrobial agents using the E test method.  

PubMed

The objective of this study was to determine the susceptibility of Mycoplasma bovis against six antibiotics using the E test methodology. Fifty-eight isolates of M. bovis originating from 55 affected cattle were evaluated. Specimen originated from: lung tissue, synovial fluid, tracheo-bronchial wash, milk, and external or inner ear discharge. Antimicrobial agents tested were azythromycin, clindamycin, erythromycin, enrofloxacin, spectinomycin and tetracycline. The E test strips were placed on the surface of Hayflick plates on which organism suspension was spread. Plates were incubated at 35 degrees C in a candle jar for 72 h. MICs were then read by determining where the growth inhibition zone intersected with the MIC scale on the strip. M. bovis Donetta isolate was used as a control. All MICs were >256 microg/ml for erythromycin. MIC50 and MIC90 obtained for azythromycin were 3 and >256 microg/ml, respectively. MIC50 and MIC90 obtained for tetracycline were 4 and 8 microg/ml, respectively. MIC50 and MIC90 obtained for spectinomycin were 2 and >1021 microg/ml, respectively. MIC50 and MIC90 obtained for clindamycin were 0.19 and >256 microg/ml, respectively. MIC50 and MIC90 obtained for enrofloxacin were 0.19 and 0.25 microg/ml, respectively. Resistance was not associated with the specimen source except for azythromycin. M. bovis susceptibilities were easily determined by the E test which demonstrated the efficacy of enrofloxacin and the acquired resistance to tetracycline, spectinomycin, azythromycin and clindamycin. PMID:15607084

Francoz, David; Fortin, Mado; Fecteau, Gilles; Messier, Serge

2005-01-01

139

Ramoplanin: a novel antimicrobial agent with the potential to prevent vancomycin-resistant enterococcal infection in high-risk patients.  

PubMed

The prevention of vancomycin-resistant Enterococcus (VRE) colonization and infection continues to be a high priority for clinicians. An oral antimicrobial agent that reduces or eliminates VRE gastrointestinal colonization could be useful for preventing VRE infection in selected patients. Ramoplanin, a glycolipodepsipeptide, is the first in a new class of antimicrobials. It has excellent in vitro activity against vancomycin-resistant Enterococcus faecium and Enterococcus faecalis. It is orally administered, and not absorbed systemically. In clinical trials, VRE gastrointestinal colonization was reduced to undetectable levels in 80-90% of patients during receipt of ramoplanin. A randomized, double-blinded, placebo-controlled multicentre study is currently being conducted to determine whether ramoplanin will prevent VRE bloodstream infection in oncology patients who are neutropenic due to treatment for a haematological malignancy or a bone marrow/stem cell transplant. PMID:12801940

Montecalvo, Marisa A

2003-06-01

140

Antimicrobial factor from Bacillus amyloliquefaciens inhibits Paenibacillus larvae, the causative agent of American foulbrood.  

PubMed

Bacillus amyloliquefaciens LBM 5006 produces an antimicrobial factor active against Paenibacillus larvae, a major honeybee pathogen. The antagonistic effect and the mode of action of the antimicrobial factor were investigated. The antibacterial activity was produced starting at mid-logarithmic growth phase, reaching its maximum during the stationary phase. Exposure of cell suspensions of P. larvae to this antimicrobial resulted in loss of cell viability and reduction in optical density associated with cell lysis. Scanning electron microscopy showed damaged cell envelope and loss of protoplasmic material. The antimicrobial factor was stable for up to 80°C, but it was sensitive to proteinase K and trypsin. Mass spectrometry analysis indicates that the antimicrobial activity is associated with iturin-like peptides. The antimicrobial factor from B. amyloliquefaciens LBM 5006 showed a bactericidal effect against P. larvae cells and spores. This is the first report on iturin activity against P. larvae. This antimicrobial presents potential for use in the control of American foulbrood disease. PMID:21858429

Benitez, Lisianne Brittes; Velho, Renata Voltolini; de Souza da Motta, Amanda; Segalin, Jéferson; Brandelli, Adriano

2012-03-01

141

Cysteamine (Lynovex®), a novel mucoactive antimicrobial & antibiofilm agent for the treatment of cystic fibrosis.  

PubMed

BackgroundThere remains a critical need for more effective, safe, long-term treatments for cystic fibrosis (CF). Any successful therapeutic strategy designed to combat the respiratory pathology of this condition must address the altered lung physiology and recurrent, complex, polymicrobial infections and biofilms that affect the CF pulmonary tract. Cysteamine is a potential solution to these unmet medical needs and is described here for the first time as (Lynovex®) a single therapy with the potential to deliver mucoactive, antibiofilm and antibacterial properties; both in oral and inhaled delivery modes. Cysteamine is already established in clinical practice for an unrelated orphan condition, cystinosis, and is therefore being repurposed (in oral form) for cystic fibrosis from a platform of over twenty years of safety data and clinical experience.MethodsThe antibacterial and antibiofilm attributes of cysteamine were determined against type strain and clinical isolates of CF relevant pathogens using CLSI standard and adapted microbiological methods and a BioFlux microfluidic system. Assays were performed in standard nutrient media conditions, minimal media, to mimic the low metabolic activity of microbes/persister cells in the CF respiratory tract and in artificial sputum medium. In vivo antibacterial activity was determined in acute murine lung infection/cysteamine nebulisation models. The mucolytic potential of cysteamine was assessed against DNA and mucin in vitro by semi-quantitative macro-rheology. In all cases, the `gold standard¿ therapeutic agents were employed as control/comparator compounds against which the efficacy of cysteamine was compared.ResultsCysteamine demonstrated at least comparable mucolytic activity to currently available mucoactive agents. Cysteamine was rapidly bactericidal against both metabolically active and persister cells of Pseudomonas aeruginosa and also emerging CF pathogens; its activity was not sensitive to high ionic concentrations characteristic of the CF lung. Cysteamine prevented the formation of, and disrupted established P. aeruginosa biofilms. Cysteamine was synergistic with conventional CF antibiotics; reversing antibiotic resistance/insensitivity in CF bacterial pathogens. ConclusionsThe novel mucolytic-antimicrobial activity of cysteamine (Lynovex®) provides potential for a much needed new therapeutic strategy in cystic fibrosis. The data we present here provides a platform for cysteamine¿s continued investigation as a novel treatment for this poorly served orphan disease. PMID:25433388

Charrier, Cedric; Rodger, Catherine; Robertson, Jennifer; Kowalczuk, Aleksandra; Shand, Nicola; Fraser-Pitt, Douglas; Mercer, Derry; O Neil, Deborah

2014-11-30

142

Efficacy of antimicrobial agents in lettuce leaf processing water for control of Escherichia coli O157:H7.  

PubMed

The objectives of this research were to study transfer and control of Escherichia coli O157:H7 during simultaneous washing of inoculated and uninoculated lettuce pieces and to determine the efficacy of antimicrobial agents (peroxyacetic acid, mixed peracid, and sodium hypochlorite) on reducing the transfer of E. coli O157:H7 through processing water with or without organic load. Lettuce leaf pieces (5 by 5 cm) were inoculated with a five-strain mixture of green fluorescent protein-labeled E. coli O157:H7 at 5.6 log CFU per piece. One inoculated lettuce piece was added to five uninoculated leaves during washing. Peroxyacetic acid and mixed peracid were tested at 10, 20, and 30 ppm, and chlorine was tested at 30 and 50 ppm. No organic load (liquefied lettuce leaves) and 10% organic load in processing water were compared. Without organic load, peroxyacetic acid at 30 ppm, mixed peracid at 10, 20, and 30 ppm, and chlorine at 30 and 50 ppm all significantly reduced E. coli O157: H7 in processing water by 1.83, 1.73, 1.50, 1.83, 1.34, and 1.83 log CFU/ml, respectively, compared with washing with water alone. These antimicrobials at all concentrations tested also significantly reduced transfer of the bacteria from an inoculated leaf to uninoculated leaves in the processing water by 0.96 to 2.57 log CFU per piece. A 10% organic load in the processing water reduced efficacy of antimicrobial agents. In this contaminated water, peroxyacetic acid at 10 and 20 ppm and chlorine at 30 ppm produced effects not significantly different from those of water alone. Therefore, it is important to understand the impact of organic load when validating the effectiveness of antimicrobial treatments. PMID:19681260

Zhang, Guodong; Ma, Li; Phelan, Vanessa H; Doyle, Michael P

2009-07-01

143

Nanopores, megatonnes, and milliseconds : exploring engineered peptides as antimicrobial, carbon-capture,and biocatalytic agents  

E-print Network

This work investigates the roles that peptides play in the fields of antimicrobials, surface functionalization, carbon capture, and biocatalysis. The results demonstrate that peptides, sometimes dismissed for their lack ...

Barbero, Roberto Juan

2012-01-01

144

Effects of cyclodextrins on the antimicrobial activity of plant-derived essential oil compounds.  

PubMed

Essential oils (EOs) from plants are considered to be a safer alternative when compared to synthetic antimicrobial food additives. However, a major drawback of many EOs is their hydrophobic nature, which makes them insoluble in water based media and matrices. Although cyclodextrins (CDs) can increase the solubility of EO compounds, the effects of CDs on the antimicrobial activity of EOs have not been reported. In this paper, four different EO compounds (carvacrol, eugenol, linalool and 2-pentanoylfuran) were chosen to study the influence of CDs on the solubility and antimicrobial activity on bacteria and yeast. The greatest enhancement with regards to solubility of the four test compounds was achieved by hydroxypropyl-?-CD. In most instances, not only were the minimal antimicrobial concentrations of EO compounds decreased, but the interactivity of two combined EO compounds could be strengthened by the co-addition of CDs. Furthermore, the combination of carvacrol with hydroxypropyl-?-CD caused a marked change in the major membrane lipid composition of all microorganisms investigated; while scanning electron microscopy revealed that cellular integrity was significantly affected by 2× MIC, ultimately resulting in cell lysis. PMID:22953819

Liang, Hao; Yuan, Qipeng; Vriesekoop, Frank; Lv, Fei

2012-12-01

145

Plant extracts as natural amoebicidal agents  

Microsoft Academic Search

Strains of Acanthamoeba sp. constitute a factor contributing to the occurrence of chronic granulomatous amoebic encephalitis, keratitis, pneumonia,\\u000a as well as inflammations of other organs. Treatment of these diseases is very difficult and not always effective. A majority\\u000a of these infections have been fatal. The aim of our study was to examine the amoebicidal or amoebistatic activity of plant\\u000a extracts

Monika Derda; Edward Hada?; Barbara Thiem

2009-01-01

146

In Vitro Activities of 15 Antimicrobial Agents against 110 Toxigenic Clostridium difficile Clinical Isolates Collected from 1983 to 2004?  

PubMed Central

The incidence and severity of Clostridium difficile-associated disease (CDAD) is increasing, and standard treatment is not always effective. Therefore, more-effective antimicrobial agents and treatment strategies are needed. We used the agar dilution method to determine the in vitro susceptibility of the following antimicrobials against 110 toxigenic clinical isolates of C. difficile from 1983 to 2004, primarily from the United States: doripenem, meropenem, gatifloxacin, levofloxacin, moxifloxacin, OPT-80, ramoplanin, rifalazil, rifaximin, nitazoxanide, tizoxanide, tigecycline, vancomycin, tinidazole, and metronidazole. Included among the isolates tested were six strains of the toxinotype III, NAP1/BI/027 group implicated in recent U.S., Canadian, and European outbreaks. The most active agents in vitro were rifaximin, rifalazil, tizoxanide, nitazoxanide, and OPT-80 with MICs at which 50% of the isolates are inhibited (MIC50) and MIC90 values of 0.0075 and 0.015 ?g/ml, 0.0075 and 0.03 ?g/ml, 0.06 and 0.125 ?g/ml, 0.06 and 0.125 ?g/ml, 0.125 and 0.125 ?g/ml, respectively. However, for three isolates the rifalazil and rifaximin MICs were very high (MIC of >256 ?g/ml). Ramoplanin, vancomycin, doripenem, and meropenem were also very active in vitro with narrow MIC50 and MIC90 ranges. None of the isolates were resistant to metronidazole, the only agent for which there are breakpoints, with tinidazole showing nearly identical results. These in vitro susceptibility results are encouraging and support continued evaluation of selected antimicrobials in clinical trials of treatment for CDAD. PMID:17517836

Hecht, David W.; Galang, Minerva A.; Sambol, Susan P.; Osmolski, James R.; Johnson, Stuart; Gerding, Dale N.

2007-01-01

147

Activity of nine oral agents against gram-positive and gram-negative bacteria encountered in community-acquired infections: Use of pharmacokinetic\\/pharmacodynamic breakpoints in the comparative assessment of beta-lactam and macrolide antimicrobial agents  

Microsoft Academic Search

Background: The application of pharmacokinetic (PK) and pharmacodynamic (PD) data in conjunction with minimum inhibitory concentrations (MICs) of antibacterial agents has been shown to allow for improved selection and appropriate dosing of antimicrobial agents for specific infections, increasing the likelihood of bacteriologic cure and, through this, reducing the risk for the development of resistant organisms.Objectives: This study was undertaken to

Mihaela Peric; Frederick A Browne; Michael R Jacobs; Peter C Appelbaum

2003-01-01

148

Antimicrobial and antioxidant activities of Cortex Magnoliae Officinalis and some other medicinal plants commonly used in South-East Asia  

PubMed Central

Background Eight medicinal plants were tested for their antimicrobial and antioxidant activities. Different extraction methods were also tested for their effects on the bioactivities of the medicinal plants. Methods Eight plants, namely Herba Polygonis Hydropiperis (Laliaocao), Folium Murraya Koenigii (Jialiye), Rhizoma Arachis Hypogea (Huashenggen), Herba Houttuyniae (Yuxingcao), Epipremnum pinnatum (Pashulong), Rhizoma Typhonium Flagelliforme (Laoshuyu), Cortex Magnoliae Officinalis (Houpo) and Rhizoma Imperatae (Baimaogen) were investigated for their potential antimicrobial and antioxidant properties. Results Extracts of Cortex Magnoliae Officinalis had the strongest activities against M. Smegmatis, C. albicans, B. subtilis and S. aureus. Boiled extracts of Cortex Magnoliae Officinalis, Folium Murraya Koenigii, Herba Polygonis Hydropiperis and Herba Houttuyniae demonstrated greater antioxidant activities than other tested medicinal plants. Conclusion Among the eight tested medicinal plants, Cortex Magnoliae Officinalis showed the highest antimicrobial and antioxidant activities. Different methods of extraction yield different spectra of bioactivities. PMID:19038060

Chan, Lai Wah; Cheah, Emily LC; Saw, Constance LL; Weng, Wanyu; Heng, Paul WS

2008-01-01

149

[Antimicrobial susceptibility testing in clinically relevant non-fermenting gram-negative bacilli: recommendations from the Antimicrobial Agents Subcommittee of the Sociedad Argentina de Bacteriología, Micología y Parasitología Clínicas, Asociación Argentina de Microbiología].  

PubMed

This document contains the recommendations for antimicrobial susceptibility testing of the clinically relevant non-fermenting gram-negative bacilli (NFGNB), adopted after conforming those from international committees to the experience of the Antimicrobial Agents Subcommittee members and invited experts. This document includes an update on NFGNB classification and description, as well as some specific descriptions regarding natural or frequent antimicrobial resistance and a brief account of associated resistance mechanisms. These recommendations not only suggest the antimicrobial drugs to be evaluated in each case, but also provide an optimization of the disk diffusion layout and a selection of results to be reported. Finally, this document also includes a summary of the different methodological approaches that may be used for detection and confirmation of emerging b-lactamases, such as class A and B carbapenemases. PMID:21731977

Radice, Marcela; Marín, Marcelo; Giovanakis, Marta; Vay, Carlos; Almuzara, Marisa; Limansky, Adriana; Casellas, José M; Famiglietti, Angela; Quinteros, Mirta; Bantar, Carlos; Galas, Marcelo; Kovensky Pupko, Jaime; Nicola, Federico; Pasterán, Fernando; Soloaga, Rolando; Gutkind, Gabriel

2011-01-01

150

Plant antimicrobial peptides snakin-1 and snakin-2: chemical synthesis and insights into the disulfide connectivity.  

PubMed

Antimicrobial peptides and proteins represent an important class of plant defensive compounds against pathogens and provide a rich source of lead compounds in the field of drug discovery. We describe the effective preparation of the cysteine-rich snakin-1 and -2 antimicrobial peptides by using a combination of solid-phase synthesis and native chemical ligation. A subsequent cysteine/cystine mediated oxidative folding to form the six internal disulfide bonds concurrently gave the folded proteins in 40-50?% yield. By comparative evaluation of mass spectrometry, HPLC, biological data and trypsin digest mapping of folded synthetic snakin-2 compared to natural snakin-2, we demonstrated that synthetic snakin-2 possesses full antifungal activity and displayed similar chromatographic behaviour to natural snakin-2. Trypsin digest analysis allowed tentative assignment of three of the purported six disulfide bonds. PMID:24644073

Harris, Paul W R; Yang, Sung-Hyun; Molina, Antonio; López, Gemma; Middleditch, Martin; Brimble, Margaret A

2014-04-22

151

Investigation of Vietnamese plants for potential anticancer agents.  

PubMed

Higher plants continue to afford humankind with many new drugs, for a variety of disease types. In this review, recent phytochemical and biological progress is presented for part of a collaborative multi-institutional project directed towards the discovery of new antitumor agents. The specific focus is on bioactive natural products isolated and characterized structurally from tropical plants collected in Vietnam. The plant collection, identification, and processing steps are described, and the natural products isolated from these species are summarized with their biological activities. PMID:25395897

Pérez, Lynette Bueno; Still, Patrick C; Naman, C Benjamin; Ren, Yulin; Pan, Li; Chai, Hee-Byung; Carcache de Blanco, Esperanza J; Ninh, Tran Ngoc; Van Thanh, Bui; Swanson, Steven M; Soejarto, Djaja D; Kinghorn, A Douglas

2014-12-01

152

Novel Antimicrobial Agents: Fluorinated 2-(3-(Benzofuran-2-yl) pyrazol-1-yl)thiazoles.  

PubMed

A new series of 2-pyrazolin-1-ylthiazoles 8a-d and 13-16 was synthesized by cyclization of N-thiocarboxamide-2-pyrazoline with different haloketones and 2,3-dichloroquinoxaline. The structures of the new compounds were confirmed by elemental analyses as well as NMR, IR, and mass spectral data. The newly synthesized compounds were evaluated for their antimicrobial activities, and also their minimum inhibitory concentration (MIC) against most of test organisms was performed. Amongst the tested ones, compound 8c displayed excellent antimicrobial activity. PMID:25379293

Mohamed, Hanan A; Abdel-Latif, Ehab; Abdel-Wahab, Bakr F; Awad, Ghada E A

2013-01-01

153

Novel Antimicrobial Agents: Fluorinated 2-(3-(Benzofuran-2-yl) pyrazol-1-yl)thiazoles  

PubMed Central

A new series of 2-pyrazolin-1-ylthiazoles 8a–d and 13–16 was synthesized by cyclization of N-thiocarboxamide-2-pyrazoline with different haloketones and 2,3-dichloroquinoxaline. The structures of the new compounds were confirmed by elemental analyses as well as NMR, IR, and mass spectral data. The newly synthesized compounds were evaluated for their antimicrobial activities, and also their minimum inhibitory concentration (MIC) against most of test organisms was performed. Amongst the tested ones, compound 8c displayed excellent antimicrobial activity. PMID:25379293

Mohamed, Hanan A.; Abdel-Latif, Ehab; Abdel-Wahab, Bakr F.; Awad, Ghada E. A.

2013-01-01

154

Discovery of new anticancer agents from higher plants  

PubMed Central

1. ABSTRACT Small organic molecules derived from higher plants have been one of the mainstays of cancer chemotherapy for approximately the past half a century. In the present review, selected single chemical entity natural products of plant origin and their semi-synthetic derivatives currently in clinical trials are featured as examples of new cancer chemotherapeutic drug candidates. Several more recently isolated compounds obtained from plants showing promising in vivo biological activity are also discussed in terms of their potential as anticancer agents, with many of these obtained from species that grow in tropical regions. Since extracts of only a relatively small proportion of the ca. 300,000 higher plants on earth have been screened biologically to date, bioactive compounds from plants should play an important role in future anticancer drug discovery efforts. PMID:22202049

Pan, Li; Chai, Hee-Byung; Kinghorn, A. Douglas

2012-01-01

155

Effect of tea tree (Melaleuca alternifolia) oil as a natural antimicrobial agent in lipophilic formulations.  

PubMed

There has been increased interest surrounding the use of tea tree oil (TTO) as a natural antimicrobial. In this study, the antimicrobial activity of TTO and its components were investigated in vitro and in a predominantly lipid-based personal care formulation. In vitro, TTO showed minimal inhibitory concentrations of 0.2% (for Saccharomyces cerevisiae and Pythium sulcatum), 0.4% (for Escherichia coli, Bacillus subtilis, and Rhizopus stolonifer), and 0.8% (for Botrytis cinerea). TTO at 0.08%-0.8% was often as efficient as parabens. Comparison of the antimicrobial activities of TTO components showed that terpinen-4-ol and ?-terpinene were generally most effective in inhibiting microbial growth. TTO activity in a personal care product was evaluated through air and water exposure, artificial inoculation, and shelf life studies. While TTO did not increase shelf life of unopened products, it decreased microbial load in products exposed to water and air. Results from this study support that antimicrobial activity of TTO can be attributed to varying levels of its components and that low levels of TTO were effective in reducing microbial growth during the use of the product. This study showed that TTO can act as a suitable preservative system within an oil-based formulation. PMID:25515896

Mantil, Elisabeth; Daly, Grace; Avis, Tyler J

2015-01-01

156

Biodiversity of thermotolerant Bacillus sp. producing biosurfactants, biocatalysts, and antimicrobial agents  

Microsoft Academic Search

Thermotolerant bacteria isolated from soil and water samples taken from 76 hot springs in Thailand were investigated for their biosurfactant, biocatalytic, and antimicrobial properties. DNA samples purified from 148 pure isolates were PCR amplified using primers specific for the 16S rDNA hypervariable region of the genus Bacillus. The DNAPAR phylogenetic tree clearly demonstrated that these isolates were related to Bacillus

Arda Pakpitcharoena

157

Which Approach Is More Effective in the Selection of Plants with Antimicrobial Activity?  

PubMed Central

The development of the present study was based on selections using random, direct ethnopharmacological, and indirect ethnopharmacological approaches, aiming to evaluate which method is the best for bioprospecting new antimicrobial plant drugs. A crude extract of 53 species of herbaceous plants collected in the semiarid region of Northeast Brazil was tested against 11 microorganisms. Well-agar diffusion and minimum inhibitory concentration (MIC) techniques were used. Ten extracts from direct, six from random, and three from indirect ethnopharmacological selections exhibited activities that ranged from weak to very active against the organisms tested. The strain most susceptible to the evaluated extracts was Staphylococcus aureus. The MIC analysis revealed the best result for the direct ethnopharmacological approach, considering that some species yielded extracts classified as active or moderately active (MICs between 250 and 1000?µg/mL). Furthermore, one species from this approach inhibited the growth of the three Candida strains. Thus, it was concluded that the direct ethnopharmacological approach is the most effective when selecting species for bioprospecting new plant drugs with antimicrobial activities. PMID:23878595

Silva, Ana Carolina Oliveira; Santana, Elidiane Fonseca; Saraiva, Antonio Marcos; Coutinho, Felipe Neves; Castro, Ricardo Henrique Acre; Pisciottano, Maria Nelly Caetano; Amorim, Elba Lúcia Cavalcanti; Albuquerque, Ulysses Paulino

2013-01-01

158

A potent antimicrobial protein from onion seeds showing sequence homology to plant lipid transfer proteins.  

PubMed Central

An antimicrobial protein of about 10 kD, called Ace-AMP1, was isolated from onion (Allium cepa L.) seeds. Based on the near-complete amino acid sequence of this protein, oligonucleotides were designed for polymerase chain reaction-based cloning of the corresponding cDNA. The mature protein is homologous to plant nonspecific lipid transfer proteins (nsLTPs), but it shares only 76% of the residues that are conserved among all known plant nsLTPs and is unusually rich in arginine. Ace-AMP1 inhibits all 12 tested plant pathogenic fungi at concentrations below 10 micrograms mL-1. Its antifungal activity is either not at all or is weakly affected by the presence of different cations at concentrations approximating physiological ionic strength conditions. Ace-AMP1 is also active on two Gram-positive bacteria but is apparently not toxic for Gram-negative bacteria and cultured human cells. In contrast to nsLTPs such as those isolated from radish or maize seeds, Ace-AMP1 was unable to transfer phospholipids from liposomes to mitochondria. On the other hand, lipid transfer proteins from wheat and maize seeds showed little or no antimicrobial activity, whereas the radish lipid transfer protein displayed antifungal activity only in media with low cation concentrations. The relevance of these findings with regard to the function of nsLTPs is discussed. PMID:7480341

Cammue, B P; Thevissen, K; Hendriks, M; Eggermont, K; Goderis, I J; Proost, P; Van Damme, J; Osborn, R W; Guerbette, F; Kader, J C

1995-01-01

159

Food Antimicrobials Nanocarriers  

PubMed Central

Natural food antimicrobials are bioactive compounds that inhibit the growth of microorganisms involved in food spoilage or food-borne illness. However, stability issues result in degradation and loss of antimicrobial activity. Nanoencapsulation allows protection of antimicrobial food agents from unfavorable environmental conditions and incompatibilities. Encapsulation of food antimicrobials control delivery increasing the concentration of the antimicrobials in specific areas and the improvement of passive cellular absorption mechanisms resulted in higher antimicrobial activity. This paper reviews the present state of the art of the nanostructures used as food antimicrobial carriers including nanoemulsions, nanoliposomes, nanoparticles, and nanofibers. PMID:24995363

Blanco-Padilla, Adriana; Soto, Karen M.; Hernández Iturriaga, Montserrat

2014-01-01

160

Metabolomics reveals the origins of antimicrobial plant resins collected by honey bees.  

PubMed

The deposition of antimicrobial plant resins in honey bee, Apis mellifera, nests has important physiological benefits. Resin foraging is difficult to approach experimentally because resin composition is highly variable among and between plant families, the environmental and plant-genotypic effects on resins are unknown, and resin foragers are relatively rare and often forage in unobservable tree canopies. Subsequently, little is known about the botanical origins of resins in many regions or the benefits of specific resins to bees. We used metabolomic methods as a type of environmental forensics to track individual resin forager behavior through comparisons of global resin metabolite patterns. The resin from the corbiculae of a single bee was sufficient to identify that resin's botanical source without prior knowledge of resin composition. Bees from our apiary discriminately foraged for resin from eastern cottonwood (Populus deltoides), and balsam poplar (P. balsamifera) among many available, even closely related, resinous plants. Cottonwood and balsam poplar resin composition did not show significant seasonal or regional changes in composition. Metabolomic analysis of resin from 6 North American Populus spp. and 5 hybrids revealed peaks characteristic to taxonomic nodes within Populus, while antimicrobial analysis revealed that resin from different species varied in inhibition of the bee bacterial pathogen, Paenibacillus larvae. We conclude that honey bees make discrete choices among many resinous plant species, even among closely related species. Bees also maintained fidelity to a single source during a foraging trip. Furthermore, the differential inhibition of P. larvae by Populus spp., thought to be preferential for resin collection in temperate regions, suggests that resins from closely related plant species many have different benefits to bees. PMID:24204850

Wilson, Michael B; Spivak, Marla; Hegeman, Adrian D; Rendahl, Aaron; Cohen, Jerry D

2013-01-01

161

Plant ferredoxin-like protein (PFLP) exhibits an anti-microbial ability against soft-rot pathogen Erwinia carotovora subsp. carotovora in vitro and in vivo  

Microsoft Academic Search

The anti-microbial protein was frequently used to control the plant bacterial disease. In this study, it was investigated that the anti-microbial activity of recombinant plant ferredoxin-like protein (PFLP) both in vitro and in vivo. The in vitro assay demonstrated that PFLP produced by transformed Escherichia coli exhibited an anti-microbial activity against several bacteria strain including E. coli, Erwiniacarotovora and Pseudomonas

Hsiang-En Huang; Mang-Jye Ger; Chao-Ying Chen; Mei-Kuen Yip; Mei-Chu Chung; Teng-Yung Feng

2006-01-01

162

Application of Origanum majorana L. essential oil as an antimicrobial agent in sausage.  

PubMed

This work reports on the antimicrobial activity in fresh sausage of marjoram (Origanum majorana L.) essential oil against several species of bacteria. The in vitro minimum inhibitory concentration (MIC) was determined for 10 selected aerobic heterotrophic bacterial species. The antimicrobial activity of distinct concentrations of the essential oil based on the highest MIC value was tested in a food system comprising fresh sausage. Batch food samples were also inoculated with a fixed concentration of Escherichia coli and the time course of the product was evaluated with respect to the action of the different concentrations of essential oil. Results showed that addition of marjoram essential oil to fresh sausage exerted a bacteriostatic effect at oil concentrations lower than the MIC, while a bactericidal effect was observed at higher oil concentrations which also caused alterations in the taste of the product. PMID:17993397

Busatta, C; Vidal, R S; Popiolski, A S; Mossi, A J; Dariva, C; Rodrigues, M R A; Corazza, F C; Corazza, M L; Vladimir Oliveira, J; Cansian, R L

2008-02-01

163

Silver polymeric nanocomposites as advanced antimicrobial agents: classification, synthetic paths, applications, and perspectives.  

PubMed

Utilization of metallic nanoparticles in various biotechnological and medical applications represents one of the most extensively investigated areas of the current materials science. These advanced applications require the appropriate chemical functionalization of the nanoparticles with organic molecules or their incorporation in suitable polymer matrices. The intensified interest in polymer nanocomposites with silver nanoparticles is due to the high antimicrobial effect of nanosilver as well as the unique characteristics of polymers which include their excellent structural uniformity, multivalency, high degree of branching, miscellaneous morphologies and architectures, and highly variable chemical composition. In this review, we explore several aspects of antimicrobial polymer silver nanocomposites, giving special focus to the critical analysis of the reported synthetic routes including their advantages, drawbacks, possible improvements, and real applicability in antibacterial and antifungal therapy. A special attention is given to "green" synthetic routes exploiting the biopolymeric matrix and to the methods allowing preparing magnetically controllable antimicrobial polymers for targeting to an active place. The controversial mechanism of the action of silver against bacteria, fungi and yeasts as well as perspectives and new applications of silver polymeric nanocomposites is also briefly discussed. PMID:21683320

Dallas, Panagiotis; Sharma, Virender K; Zboril, Radek

2011-08-10

164

Exploiting innate immune cell activation of a copper-dependent antimicrobial agent during infection.  

PubMed

Recalcitrant microbial infections demand new therapeutic options. Here we present an approach that exploits two prongs of the host immune cell antimicrobial response: the oxidative burst and the compartmentalization of copper (Cu) within phagolysosomes. The prochelator QBP is a nontoxic protected form of 8-hydroxyquinoline (8HQ) in which a pinanediol boronic ester blocks metal ion coordination by 8HQ. QBP is deprotected via reactive oxygen species produced by activated macrophages, creating 8HQ and eliciting Cu-dependent killing of the fungal pathogen Cryptococcus neoformans in vitro and in mouse pulmonary infection. 8HQ ionophoric activity increases intracellular Cu, overwhelming the Cu-resistance mechanisms of C. neoformans to elicit fungal killing. The Cu-dependent antimicrobial activity of 8HQ against a spectrum of microbial pathogens suggests that this strategy may have broad utility. The conditional activation of Cu ionophores by innate immune cells intensifies the hostile antimicrobial environment and represents a promising approach to combat infectious disease. PMID:25088681

Festa, Richard A; Helsel, Marian E; Franz, Katherine J; Thiele, Dennis J

2014-08-14

165

Evaluation of the in vitro activity of six broad-spectrum ?-lactam antimicrobial agents tested against over 2,000 clinical isolates from 22 medical centers in Japan  

Microsoft Academic Search

Numerous broad-spectrum ?-lactam antimicrobial agents have been introduced into medical practice since 1985. Although several of these compounds have advanced, infectious disease therapy resistances to them has also emerged world-wide. In 1997, a Japanese 22 medical center investigation was initiated to assess the continued utility of these agents (oxacillin or piperacillin, ceftazidime, cefepime, cefpirome, cefoperazone\\/sulbactam [C\\/S], imipenem). The participating medical

Keizo Yamaguchi; Dilip Mathai; Douglas J Biedenbach; M. Todd Lewis; Ana C Gales; Ronald N Jones

1999-01-01

166

Effect of ionizing energy on extracts of Quillaja saponaria to be used as an antimicrobial agent on irradiated edible coating for fresh strawberries  

Microsoft Academic Search

Incorporating antimicrobial compounds into edible films or coatings provides a novel way to improve the safety and shelf life of ready-to-eat foods. Diverse studies with Quillaja saponaria Mol. (popularly named quillay) extracts have demonstrated their potential as antifungal agents against phytopathogenic fungi. Crosslinking induced by ionizing radiation is an effective method for the improvement of both barrier and mechanical properties

G. E. Zúñiga; M. P. Junqueira-Gonçalves; M. Pizarro; R. Contreras; A. Tapia; S. Silva

2012-01-01

167

Activities of Antifungal Agents against Yeasts and Filamentous Fungi: Assessment according to the Methodology of the European Committee on Antimicrobial Susceptibility Testing  

Microsoft Academic Search

We compared the activities of antifungal agents against a wide range of yeasts and filamentous fungi. The methodology of the European Committee on Antimicrobial Susceptibility Testing (EUCAST) for yeasts and spore-forming molds was applied; and a total of 349 clinical isolates of Candida spp., other yeast species, Aspergillus spp., and nondermatophyte non-Aspergillus spp. were investigated. The average geometric mean (GM)

Cornelia Lass-Florl; Astrid Mayr; Susanne Perkhofer; Guido Hinterberger; Johann Hausdorfer; Cornelia Speth; Manfred Fille

2008-01-01

168

Antimicrobial, Antioxidant and Cytotoxic Activities and Phytochemical Screening of Some Yemeni Medicinal Plants  

PubMed Central

The traditional medicine still plays an important role in the primary health care in Yemen. The current study represents the investigation of 16 selected plants, which were collected from different localities of Yemen. The plants were dried and extracted with two different solvents (methanol and hot water) to yield 34 crude extracts. The obtained extracts were tested for their antimicrobial activity against three Gram-positive bacteria, two Gram-negative bacteria, one yeast species and three multiresistant Staphylococcus strains using agar diffusion method, for their antioxidant activity using scavenging activity of DPPH radical method and for their cytotoxic activity using the neutral red uptake assay. In addition, a phytochemical screening of the methanolic extracts was done. Antibacterial activity was shown only against Gram-positive bacteria, among them multiresistant bacteria. The highest antimicrobial activity was exhibited by the methanolic extracts of Acalypha fruticosa, Centaurea pseudosinaica, Dodonaea viscosa, Jatropha variegata, Lippia citriodora, Plectranthus hadiensis, Tragia pungens and Verbascum bottae. Six methanolic extracts especially those of A. fruticosa, Actiniopteris semiflabellata, D. viscosa, P. hadiensis, T. pungens and V. bottae showed high free radical scavenging activity. Moreover, remarkable cytotoxic activity against FL-cells was found for the methanolic extracts of A. fruticosa, Iris albicans, L. citriodora and T. pungens. The phytochemical screening demonstrated the presence of different types of compounds like flavonoids, terpenoids and others, which could be responsible for the obtained activities. PMID:18955315

Abdo, Salah A. A.; Hasson, Sidgi; Althawab, Faisal M. N.; Alaghbari, Sama A. Z.; Lindequist, Ulrike

2010-01-01

169

Antimicrobial, antioxidant and cytotoxic activities and phytochemical screening of some yemeni medicinal plants.  

PubMed

The traditional medicine still plays an important role in the primary health care in Yemen. The current study represents the investigation of 16 selected plants, which were collected from different localities of Yemen. The plants were dried and extracted with two different solvents (methanol and hot water) to yield 34 crude extracts. The obtained extracts were tested for their antimicrobial activity against three Gram-positive bacteria, two Gram-negative bacteria, one yeast species and three multiresistant Staphylococcus strains using agar diffusion method, for their antioxidant activity using scavenging activity of DPPH radical method and for their cytotoxic activity using the neutral red uptake assay. In addition, a phytochemical screening of the methanolic extracts was done. Antibacterial activity was shown only against Gram-positive bacteria, among them multiresistant bacteria. The highest antimicrobial activity was exhibited by the methanolic extracts of Acalypha fruticosa, Centaurea pseudosinaica, Dodonaea viscosa, Jatropha variegata, Lippia citriodora, Plectranthus hadiensis, Tragia pungens and Verbascum bottae. Six methanolic extracts especially those of A. fruticosa, Actiniopteris semiflabellata, D. viscosa, P. hadiensis, T. pungens and V. bottae showed high free radical scavenging activity. Moreover, remarkable cytotoxic activity against FL-cells was found for the methanolic extracts of A. fruticosa, Iris albicans, L. citriodora and T. pungens. The phytochemical screening demonstrated the presence of different types of compounds like flavonoids, terpenoids and others, which could be responsible for the obtained activities. PMID:18955315

Mothana, Ramzi A A; Abdo, Salah A A; Hasson, Sidgi; Althawab, Faisal M N; Alaghbari, Sama A Z; Lindequist, Ulrike

2010-09-01

170

Production of Phytotoxic Cationic ?-Helical Antimicrobial Peptides in Plant Cells Using Inducible Promoters  

PubMed Central

Synthetic linear antimicrobial peptides with cationic ?-helical structures, such as BP100, have potent and specific activities against economically important plant pathogenic bacteria. They are also recognized as valuable therapeutics and preservatives. However, highly active BP100 derivatives are often phytotoxic when expressed at high levels as recombinant peptides in plants. Here we demonstrate that production of recombinant phytotoxic peptides in transgenic plants is possible by strictly limiting transgene expression to certain tissues and conditions, and specifically that minimization of this expression during transformation and regeneration of transgenic plants is essential to obtain viable plant biofactories. On the basis of whole-genome transcriptomic data available online, we identified the Os.hsp82 promoter that fulfilled this requirement and was highly induced in response to heat shock. Using this strategy, we generated transgenic rice lines producing moderate yields of severely phytotoxic BP100 derivatives on exposure to high temperature. In addition, a threshold for gene expression in selected tissues and stages was experimentally established, below which the corresponding promoters should be suitable for driving the expression of recombinant phytotoxic proteins in genetically modified plants. In view of the growing transcriptomics data available, this approach is of interest to assist promoter selection for specific purposes. PMID:25387106

Company, Nuri; Nadal, Anna; Ruiz, Cristina; Pla, Maria

2014-01-01

171

Antimicrobial activity of some water plants from the northeastern Anatolian region of Turkey.  

PubMed

The antimicrobial activity of methanol and acetone extracts of Butomus umbellatus, Polygonum amphibium, and two species of the genus Sparganium (S. erectum and S. emersum)against three Gram-positive, five Gram-negative bacteria and one fungus was assessed by the disk diffusion method. The microorganisms used were Staphylococcus aureusATCC-29740, Escherichia coli ATCC-25922, Pseudomonas aeruginosa ATCC-15442, Salmonella typhi NCTC-9394, Klebsiella pneumoniae NCTC-5046, Proteus vulgaris ATCC-7829, Bacillus subtilis ATCC-6633, Corynebacterium diphteriae RSHM-633 and Candida albicans ATCC-10231. Methanol extracts of the plants did not exhibit any inhibitory activity against any of the microorganisms, while the acetone extracts of the all tested plants only showed significant activity against Bacillus subtilis, with inhibition zones and minimal inhibitory concentration values in the 7-16 mm and 0.49-12.50 mg/mL ranges, respectively. PMID:19145212

Ozbay, Hanife; Alim, Ahmet

2009-01-01

172

Artocarpus plants as a potential source of skin whitening agents.  

PubMed

Artocarpus plants have been a focus of constant attention due to the potential for skin whitening agents. In the in vitro experiment, compounds from the Artocarpus plants, such as artocarpanone, norartocarpetin, artocarpesin, artogomezianol, andalasin, artocarbene, and chlorophorin showed tyrosinase inhibitory activity. Structure-activity investigations revealed that the 4-substituted resorcinol moiety in these compounds was responsible for their potent inhibitory activities on tyrosinase. In the in vitro assay, using B16 melanoma cells, the prenylated polyphenols isolated from Artocarpus plants, such as artocarpin, cudraflavone C, 6-prenylapigenin, kuwanon C, norartocarpin, albanin A, cudraflavone B, and brosimone I showed potent inhibitory activity on melanin formation. Structure-activity investigations revealed that the introduction of an isoprenoid moiety to a non-isoprenoid-substituted polyphenol enhanced the inhibitory activity of melanin production in B16 melanoma cells. In the in vivo investigation, the extract of the wood of Artocarpus incisus and a representative isolated compound from it, artocarpin had a lightening effect on the skin of guinea pigs' backs. Other in vivo experiments using human volunteers have shown that water extract of Artocarpus lakoocha reduced the melanin formation in the skin of volunteers. These results indicate that the extracts of Artocarpus plants are potential sources for skin whitening agents. PMID:21941923

Arung, Enos Tangke; Shimizu, Kuniyoshi; Kondo, Ryuichiro

2011-09-01

173

Antimicrobial activity of plant compounds against Salmonella Typhimurium DT104 in ground pork and the influence of heat and storage on the antimicrobial activity.  

PubMed

Salmonella enterica is a predominant foodborne pathogen that causes diarrheal illness worldwide. A potential method of inhibiting pathogenic bacterial growth in meat is through the introduction of plant-derived antimicrobials. The objectives of this study were to investigate the influence of heat (70°C for 5 min) and subsequent cold storage (4°C up to 7 days) on the effectiveness of oregano and cinnamon essential oils and powdered olive and apple extracts against Salmonella enterica serovar Typhimurium DT104 in ground pork and to evaluate the activity of the most effective antimicrobials (cinnamon oil and olive extract) at higher concentrations in heated ground pork. The surviving Salmonella populations in two groups (heated and unheated) of antimicrobial-treated pork were compared. Higher concentrations of the most effective compounds were then tested (cinnamon oil at 0.5 to 1.0% and olive extract at 3, 4, and 5%) against Salmonella Typhimurium in heated ground pork. Samples were stored at 4°C and taken on days 0, 3, 5, and 7 for enumeration of survivors. The heating process did not affect the activity of antimicrobials. Significant 1.3- and 3-log reductions were observed with 1.0% cinnamon oil and 5% olive extract, respectively, on day 7. The minimum concentration required to achieve . 1-log reduction in Salmonella population was 0.8% cinnamon oil or 4% olive extract. The results demonstrate the effectiveness of these antimicrobials against multidrug-resistant Salmonella Typhimurium in ground pork and their stability during heating and cold storage. The most active formulations have the potential to enhance the microbial safety of ground pork. PMID:23834804

Chen, Cynthia H; Ravishankar, Sadhana; Marchello, John; Friedman, Mendel

2013-07-01

174

Evaluation of the Antimicrobial Activities of Plant Oxylipins Supports Their Involvement in Defense against Pathogens1[W  

PubMed Central

Plant oxylipins are a large family of metabolites derived from polyunsaturated fatty acids. The characterization of mutants or transgenic plants affected in the biosynthesis or perception of oxylipins has recently emphasized the role of the so-called oxylipin pathway in plant defense against pests and pathogens. In this context, presumed functions of oxylipins include direct antimicrobial effect, stimulation of plant defense gene expression, and regulation of plant cell death. However, the precise contribution of individual oxylipins to plant defense remains essentially unknown. To get a better insight into the biological activities of oxylipins, in vitro growth inhibition assays were used to investigate the direct antimicrobial activities of 43 natural oxylipins against a set of 13 plant pathogenic microorganisms including bacteria, oomycetes, and fungi. This study showed unequivocally that most oxylipins are able to impair growth of some plant microbial pathogens, with only two out of 43 oxylipins being completely inactive against all the tested organisms, and 26 oxylipins showing inhibitory activity toward at least three different microbes. Six oxylipins strongly inhibited mycelial growth and spore germination of eukaryotic microbes, including compounds that had not previously been ascribed an antimicrobial activity, such as 13-keto-9(Z),11(E),15(Z)-octadecatrienoic acid and 12-oxo-10,15(Z)-phytodienoic acid. Interestingly, this first large-scale comparative assessment of the antimicrobial effects of oxylipins reveals that regulators of plant defense responses are also the most active oxylipins against eukaryotic microorganisms, suggesting that such oxylipins might contribute to plant defense through their effects both on the plant and on pathogens, possibly through related mechanisms. PMID:16299186

Prost, Isabelle; Dhondt, Sandrine; Rothe, Grit; Vicente, Jorge; Rodriguez, Maria José; Kift, Neil; Carbonne, Francis; Griffiths, Gareth; Esquerré-Tugayé, Marie-Thérèse; Rosahl, Sabine; Castresana, Carmen; Hamberg, Mats; Fournier, Joëlle

2005-01-01

175

Considering the antimicrobial sensitivity of the intestinal botulism agent Clostridium butyricum when treating concomitant infections  

Microsoft Academic Search

In Italy, neurotoxigenic Clostridium butyricum has been reported as a new agent of intestinal toxemia botulism, and most of the cases have been associated with enterocolitis. Although infections concomitant with botulism must be treated with antibiotics, this can increase the severity of botulism. We discuss the sensitivity of this agent to certain antibiotics, compared to findings on the sensitivity of

Lucia Fenicia; Anna Maria Ferrini; Fabrizio Anniballi; Veruscka Mannoni; Paolo Aureli

2003-01-01

176

Synthesis of hydrazones derivatives of quinoxalinone--prospective antimicrobial and antiinflammatory agents.  

PubMed

A series of quinoxalinone derivatives was synthesized by the condensation of 1,2-diaminobenzene with alpha-ketoglutaric acid to yield 3-(3-oxo-3,4-dihydroquinoxalin-2-yl) propionic acid (2) and then treated with hydrazine hydrate to yield its hydrazones (3). This was further reacted with substituted aromatic aldehydes to produce final compounds (4a-r). These hydrazones derivatives were characterized by FT-IR and 1H-NMR data. All the synthesized compounds were evaluated for their antimicrobial and antiinflammatory activity. PMID:19719051

Khan, Suroor A; Mullick, Pooja; Pandit, Shabir; Kaushik, Darpan

2009-01-01

177

Antimicrobial and inhibitory enzyme activity of N-(benzyl) and quaternary N-(benzyl) chitosan derivatives on plant pathogens.  

PubMed

Chemical modification of a biopolymer chitosan by introducing quaternary ammonium moieties into the polymer backbone enhances its antimicrobial activity. In the present study, a series of quaternary N-(benzyl) chitosan derivatives were synthesized and characterized by (1)H-NMR, FT-IR and UV spectroscopic techniques. The antimicrobial activity against crop-threatening bacteria Agrobacterium tumefaciens and Erwinia carotovora and fungi Botrytis cinerea, Botryodiplodia theobromae, Fusarium oxysporum and Phytophthora infestans were evaluated. The results proved that the grafting of benzyl moiety or quaternization of the derivatives onto chitosan molecule was successful in inhibiting the microbial growth. Moreover, increase water-solubility of the compounds by quaternization significantly increased the activity against bacteria and fungi. Exocellular enzymes including polygalacturonase (PGase), pectin-lyase (PLase), polyphenol oxidase (PPOase) and cellulase were also affected at 1000 mg/L. These compounds especially quaternary-based chitosan derivatives that have good inhibitory effect should be potentially used as antimicrobial agents in crop protection. PMID:25037402

Badawy, Mohamed E I; Rabea, Entsar I; Taktak, Nehad E M

2014-10-13

178

Frequency of Resistance in Obligate Anaerobic Bacteria Isolated from Dogs, Cats, and Horses to Antimicrobial Agents  

PubMed Central

Clinical specimens from dogs, cats, and horses were examined for the presence of obligate anaerobic bacteria. Of 4,018 specimens cultured, 368 yielded 606 isolates of obligate anaerobic bacteria (248 from dogs, 50 from cats, and 308 from horses). There were 100 specimens from 94 animals from which only anaerobes were isolated (25 dogs, 8 cats, and 61 horses). The most common sites tested were abdominal fluid (dogs and cats) and intestinal contents (horses). The most common microorganism isolated from dogs, cats, and horses was Clostridium perfringens (75, 13, and101 isolates, respectively). The MICs of amoxicillin with clavulanate, ampicillin, chloramphenicol, metronidazole, and penicillin were determined using a gradient endpoint method for anaerobes. Isolates collected at necropsy were not tested for antimicrobial susceptibility unless so requested by the clinician. There were 1/145 isolates tested that were resistant to amoxicillin-clavulanate (resistance breakpoint ? 16/8 ?g/ml), 7/77 isolates tested were resistant to ampicillin (resistance breakpoint ? 2 ?g/ml), 4/242 isolates tested were resistant to chloramphenicol (resistance breakpoint ? 32 ?g/ml), 12/158 isolates tested were resistant to clindamycin (resistance breakpoint ? 8 ?g/ml), 10/247 isolates tested were resistant to metronidazole (resistance breakpoint ? 32 ?g/ml), and 54/243 isolates tested were resistant to penicillin (resistance breakpoint ? 2 ?g/ml). These data suggest that anaerobes are generally susceptible to antimicrobial drugs in vitro. PMID:24025899

Taylor, A.; Fajt, V. R.

2013-01-01

179

Stenusine, an antimicrobial agent in the rove beetle genus Stenus (Coleoptera, Staphylinidae)  

NASA Astrophysics Data System (ADS)

Stenusine is well known as the alkaloid, discharged by the rove beetle, genus Stenus Latreille (Coleoptera, Staphylinidae). The Stenus beetles employ the alkaloid as an escape mechanism when on water surfaces. In the case of danger, they lower their abdomen and emit stenusine from their pygidial glands. Stenusine shows a low surface tension and therefore a high spreading pressure; these properties propel the beetle quickly over the water. Many Steninae do not live in habitats with open waters, but in detritus, leaf litter, mosses, etc. This raises the possibility that stenusine might also have another function, e.g., as antibiotic or fungicide. Stenus beetles show an intense grooming behaviour. With gas chromatography mass spectrometry analyses we could prove that they cover themselves with their secretion. To tests its antimicrobial properties we conducted agar diffusion tests with stenusine and norstenusine, another substance that is abundant in most Stenus species. Both compounds have an antimicrobial effect on entomopathogenic bacteria and fungi. Stenusine not only allows for an extraordinary method of locomotion on water surfaces, it also protects the Steninae from being infested with microorganisms.

Lusebrink, Inka; Dettner, Konrad; Seifert, Karlheinz

2008-08-01

180

Biodegradable gelatin-chitosan films incorporated with essential oils as antimicrobial agents for fish preservation.  

PubMed

Essential oils of clove (Syzygium aromaticum L.), fennel (Foeniculum vulgare Miller), cypress (Cupressus sempervirens L.), lavender (Lavandula angustifolia), thyme (Thymus vulgaris L.), herb-of-the-cross (Verbena officinalis L.), pine (Pinus sylvestris) and rosemary (Rosmarinus officinalis) were tested for their antimicrobial activity on 18 genera of bacteria, which included some important food pathogen and spoilage bacteria. Clove essential oil showed the highest inhibitory effect, followed by rosemary and lavender. In an attempt to evaluate the usefulness of these essential oils as food preservatives, they were also tested on an extract made of fish, where clove and thyme essential oils were the most effective. Then, gelatin-chitosan-based edible films incorporated with clove essential oil were elaborated and their antimicrobial activity tested against six selected microorganisms: Pseudomonas fluorescens, Shewanella putrefaciens, Photobacterium phosphoreum, Listeria innocua, Escherichia coli and Lactobacillus acidophilus. The clove-containing films inhibited all these microorganisms irrespectively of the film matrix or type of microorganism. In a further experiment, when the complex gelatin-chitosan film incorporating clove essential oil was applied to fish during chilled storage, the growth of microorganisms was drastically reduced in gram-negative bacteria, especially enterobacteria, while lactic acid bacteria remained practically constant for much of the storage period. The effect on the microorganisms during this period was in accordance with biochemical indexes of quality, indicating the viability of these films for fish preservation. PMID:20688230

Gómez-Estaca, J; López de Lacey, A; López-Caballero, M E; Gómez-Guillén, M C; Montero, P

2010-10-01

181

Discovery and development of anticancer agents from plants.  

PubMed

A novel in vitro assay for the discovery of anticancer agents was used to examine aqueous and organic extracts from 1847 plants collected mainly in the U.S. Southwest and West. The assay results were separated into 5 categories: inactive (62%), equally active (36%), equally active and potent (0.5%), solid tumor selective (1.4%), and human selective (0.8%). Extracts from the latter three categories were fractionated using the in vitro assay to biodirect each step. Psorothamnus emoryi extracts were solid tumor selective and yielded two active compounds upon fractionation: dalrubone and 5-methoxydalrubone. Calocedrus decurrens was equally active and potent and yielded deoxypodophyllotoxin as the active compound. Linanthus floribundus was human selective and yielded strophanthidin as the active compound. The potential of this assay to discover novel anticancer agents from the active extracts is discussed. PMID:12416027

Valeriote, Fred; Grieshaber, Charles K; Media, Joseph; Pietraszkewicz, Halina; Hoffmann, Joseph; Pan, Meide; McLaughlin, Steve

2002-01-01

182

Endophytic Fungi Isolated from Coleus amboinicus Lour Exhibited Antimicrobial Activity  

PubMed Central

Purpose: Coleus amboinicus is a medicinal plant traditionally used to treat various diseases such as throat infection, cough and fever, diarrhea, nasal congestion and digestive problems. The plant was explored for endophytic fungi producing antimicrobial agents. Methods: Screening for endophytic fungi producing antimicrobial agents was conducted using agar plug method and antimicrobial activity of promising ethyl acetate extracts was determined by disc diffusion assay. Thin layer chromatography (TLC) - bioautography was performed to localize the bioactive components within the extract. TLC visualization detection reagents were used to preliminary analyze phytochemical groups of the bioactive compounds. Results: Three endophytic fungi were obtained, two of them showed promising potential. Agar diffusion method showed that endophytic fungi CAL-2 exhibited antimicrobial activity against P. aeruginosa, B. subtilis, S. aureus and S. thypi, whilst CAS-1 inhibited the growth of B. subtilis. TLC bioautography of ethyl acetate extract of CAL-2 revealed at least three bands exhibited antimicrobial activity and at least two bands showed inhibition of B. subtilis growth. Preliminary analysis of the crude extracts suggests that bioactive compounds within CAL-2 extract are terpenoids, phenolics and phenyl propanoid compounds whilst the antimicrobial agents within CAS-1 extract are terpenoids, propylpropanoids, alkaloids or heterocyclic nitrogen compounds. Conclusion: These data suggest the potential of endophytic fungi of C. amboinicus as source for antimicrobial agents. PMID:25671195

Astuti, Puji; Sudarsono, Sudarsono; Nisak, Khoirun; Nugroho, Giri Wisnu

2014-01-01

183

Effect of plant essential oils on antimicrobial and physical properties of apple-puree, edible films and coatings  

Technology Transfer Automated Retrieval System (TEKTRAN)

The use of edible films as carriers of antimicrobial plant essential oils and other phytochemicals constitutes an approach for external protection of food systems to reduce surface microbial populations and to enhance oxygen-barrier properties, thus enhancing food safety as well as shelf life. The o...

184

Evaluation of comfort properties of polyester knitted spacer fabrics finished with water repellent and antimicrobial agents  

Microsoft Academic Search

In order to impart barrier properties against water and microorganisms on breathable three dimensional spacer fabrics as medical\\u000a or technical textiles, fabric samples were treated with two water repellent agents and a quaternary ammonium salt namely cetyltrimethylammonium\\u000a bromide (CTAB), using pad-dry-cure method. Two different water repellent agents based on hydrocarbon and acrylic copolymer\\u000a were used. The water repellent property of

R. Bagherzadeh; M. Montazer; M. Latifi; M. Sheikhzadeh; M. Sattari

2007-01-01

185

In vitro activity of antimicrobial agents against Pseudomonas tolaasii, pathogen of cultivated button mushroom.  

PubMed

In vitro antibacterial activity tests of seven biofungicides (Ekstrasol, Bisolbisan, Bisolbifit, Serenade, Sonata, Timorex, F-Stop) and two disinfectants (colloidal silver alone and in combination with hydrogen peroxide) against the Pseudomonas tolaasii strain (NS3B6) were carried out by the disc-diffusion, broth microdilution and broth macrodilution method. Biofungicides tested in this study did not exhibit any antimicrobial activity in neither one of the methods used. Disc diffusion method revealed high sensitivity of the tested P. tolaasii strain to Ecocute based on colloidal silver and hydrogen peroxide. Both microdilution and macrodilution methods identified the same MICs and MBCs of Ecocute (0.19 mg/L) for P. tolaasii strain. MICs and MBCs values of silver alone were much higher (10 mg/L) compared to silver in combination with hydrogen peroxide. PMID:22375589

Todorovi?, Biljana; Milijasevi?-Mar?i?, Svetlana; Poto?nik, Ivana; Stepanovi?, Miloš; Rekanovi?, Emil; Nikoli?-Bujanovi?, Ljiljana; Cekerevac, Milan

2012-01-01

186

Potential of the essential oil from Pimenta pseudocaryophyllus as an antimicrobial agent.  

PubMed

This study evaluated the effectiveness of the essential oil of Pimenta pseudocaryophyllus in inhibiting the growth of the main bacteria responsible for bad perspiration odor (Staphylococcus epidermidis, Proteus hauseri, Micrococcus yunnanensis and Corynebacterium xerosis). The chemical profile of the essential oil was evaluated by high-resolution gas chromatography (HR-GC) and four constituents were identified, eugenol being the major component (88.6%). The antimicrobial activity was evaluated by means of the turbidimetric method, using the microdilution assay. The minimum inhibitory concentration (MIC) values of the essential oil ranged from 500 to 1,000 ?g mL?¹. Scanning electron microscope (SEM) observations confirmed the physical damage and morphological alteration of the test bacteria treated with the essential oil, reference drugs and eugenol. The findings of the study demonstrated that this essential oil can be used in the formulation of personal care products. PMID:25296683

Suzuki, Érika Yoko; Baptista, Edilene Bolutari; Resende Do Carmo, Antônio Márcio; Miranda Chaves, Maria Das Graças Afonso; Chicourel, Elizabeth Lemos; Barbosa Raposo, Nádia Rezende

2014-09-01

187

Ethnobotanical and antimicrobial study of some selected medicinal plants used in Khyber Pakhtunkhwa (KPK) as a potential source to cure infectious diseases  

PubMed Central

Background Present investigation deals with antimicrobial screening of ten medicinally important plants used by the inhabitants of district Haripur, Khyber Pakhtunkhwa (KPK) for different infectious diseases. Methods Aqueous, n-hexane and ethanolic extracts of each plant were tested for their antimicrobial activity against both Gram positive and Gram negative strains of bacteria, as well as strain of yeast. Agar well diffusion and broth dilution methods were used to determine the antimicrobial activity of different plant extracts. Results The results indicated that all plants exhibited antimicrobial activity against one or more test pathogens. Interestingly, extracts of three plants showed strong and broad spectrum activity as compared to rest of the extracts which demonstrated the moderate activity. On the whole ethanolic extracts exhibited maximum antimicrobial effect than their corresponding aqueous and n-hexane extracts, when compared with standard antibiotics i.e., Streptomycin and Tetracycline. Among various extracts, only ethanloic extract of Azadirachta indica and aqueous and ethanolic extracts of Eucalyptus globulus and Bergenia ciliata and ethanolic extract of Punica granatum were found to have potentially promising activity against test microorganisms. Conclusion Different plant extracts show promising antimicrobial activity justifying their usage in traditional medicines. This study will be continued to identify more plants with potential antimicrobial components. PMID:24708514

2014-01-01

188

Medicinal plants from Peru: a review of plants as potential agents against cancer.  

PubMed

Natural products have played a significant role in drug discovery and development especially for agents against cancer and infectious disease. An analysis of new and approved drugs for cancer by the United States Food and Drug Administration over the period of 1981-2002 showed that 62% of these cancer drugs were of natural origin. Natural compounds possess highly diverse and complex molecular structures compared to small molecule synthetic drugs and often provide highly specific biological activities likely derived from the rigidity and high number of chiral centers. Ethnotraditional use of plant-derived natural products has been a major source for discovery of potential medicinal agents. A number of native Andean and Amazonian medicines of plant origin are used as traditional medicine in Peru to treat different diseases. Of particular interest in this mini-review are three plant materials endemic to Peru with the common names of Cat's claw (Uncaria tomentosa), Maca (Lepidium meyenii), and Dragon's blood (Croton lechleri) each having been scientifically investigated for a wide range of therapeutic uses including as specific anti-cancer agents as originally discovered from the long history of traditional usage and anecdotal information by local population groups in South America. Against this background, we present an evidence-based analysis of the chemistry, biological properties, and anti-tumor activities for these three plant materials. In addition, this review will discuss areas requiring future study and the inherent limitations in their experimental use as anti-cancer agents. PMID:17017852

Gonzales, Gustavo F; Valerio, Luis G

2006-09-01

189

Production of potent antimicrobial agent by actinomycete, Streptomyces sannanensis strain SU118 isolated from phoomdi in Loktak Lake of Manipur, India.  

PubMed

BackgroundActinomycetes have provided a wealth of bioactive secondary metabolites with interesting activities such as antimicrobial, antiviral and anticancer. The study aims at isolation, characterization and the antimicrobial potentiality of Streptomyces sannanensis SU118 obtained from Phoomdi, a unique habitat of Loktak Lake of Manipur, India.ResultsAn actinomycete strain isolated from Phoomdi soil of Loktak Lake of Manipur, India was identified as Streptomyces sannanensis SU118. It is a Gram-positive filamentous bacterium which exhibits antimicrobial activity only against Gram-positive bacteria, while Gram-negative organisms were not affected. Glucose Soyabean meal broth was found to be the suitable medium for antibiotic production at 28°C for seven days of incubation. The antimicrobial agent produced by the strain was extracted with ethyl acetate as solvent and purified by thin layer chromatography. Screening and bioassay - guided fractionation of the ethyl acetate extract from the culture filtrate led to the isolation of an active potential compound (R f value 0.56) with ¿max 275.0 nm which has got the lowest minimum inhibitory concentration (0.5 ¿g/ml) against Staphylococcus aureus MTCC 96 and Staphylococcus aureus (clinical isolate), whereas highest (3.0 ¿g/ml) was recorded against Mycobacterium smegmatis MTCC 6 and Bacillus circulans MTCC 8074.ConclusionThis study has therefore uncovered the potential of exploring virgin untapped habitats in the Indo-Burma biodiversity hot spot region as reservoir of promising antimicrobial metabolite producer. These results highlighted the scope for further characterization of the metabolite and could be a candidate in the generation of new antimicrobial agents. PMID:25406714

Singh, Laishram; Sharma, Hemant; Talukdar, Narayan

2014-11-19

190

1,4Bis(2,3-epoxypropylamino)-9,10-anthracenedione and related compounds as potent antifungal and antimicrobial agents  

Microsoft Academic Search

1,4-Bis-(2,3-epoxypropylamino)-9,10-anthracenedione (1) and related derivatives were assayed for antifungal, antimicrobial, and plant growth regulatory activity. Compound 1 was extremely potent against several strains of fungi, bacteria, and algae (MIC <2 ppm) and controlled two types of downy mildew by 90–100% at a dose of 12 ppm.

Zev Lidert; David H. Young; Margaret M. Bowers-Daines; Samuel E. Sherba; Raj J. Mehta; Barry C. Lange; Colin Swithenbank; Hiroshi Kiyokawa; Mary G. Johnson; Susan L. Morris-Natschke; Kuo-Hsiung Lee

1997-01-01

191

Insights into the relationship between antimicrobial residues and bacterial populations in a hospital-urban wastewater treatment plant system.  

PubMed

The relationship between antimicrobial residues, antibiotic resistance prevalence and bacterial community composition in hospital effluent and in the receiving wastewater treatment plant was studied. Samples from hospital effluent, raw inflow and final effluent of the receiving wastewater treatment plant were characterized for amoxicillin and ciprofloxacin resistance prevalence, content of heavy metals and antimicrobial residues and bacterial community structure, based on 16S rRNA gene PCR-DGGE analysis. The concentration of fluoroquinolones, arsenic and mercury was in general higher in hospital effluent than in raw inflow, while the opposite was observed for tetracyclines, sulfonamides and penicillin G. The prevalence of ciprofloxacin resistance was significantly higher in hospital effluent than in raw inflow. The concentration of antimicrobial residues was observed to be significantly correlated with the prevalence of antibiotic resistant bacteria and with variations in the bacterial community. Hospital effluent was confirmed as a relevant, although not unique, source of antimicrobial residues and antibiotic resistant bacteria to the wastewater treatment plant. Moreover, given the high loads of antibiotic residues and antibiotic resistant bacteria that may occur in hospital effluents, these wastewater habitats may represent useful models to study and predict the impact of antibiotic residues on bacterial communities. PMID:24583524

Varela, Ana Rita; André, Sandra; Nunes, Olga C; Manaia, Célia M

2014-05-01

192

European Committee on Antimicrobial Susceptibility Testing (EUCAST) Technical Notes on antimicrobial susceptibility testing  

Microsoft Academic Search

The main objectives of the European Committee on Antimicrobial Susceptibility Testing (EUCAST) are to harmonise breakpoints for antimicrobial agents in Europe, and to act as the breakpoint committee for the European Medicines Agency (EMEA) during the registration of new antimicrobial agents. Detailed EUCAST procedures for harmonising and setting breakpoints for antimicrobial agents are available on the EUCAST website. Beginning with

G. Kahlmeter; D. F. J. Brown; F. W. Goldstein; A. P. MacGowan; J. W. Mouton; I. Odenholt; A. Rodloff; C. J. Soussy; M. Steinbakk; F. Soriano; O. Stetsiouk

2006-01-01

193

Molecular genetic basis of antimicrobial agent resistance in Mycobacterium tuberculosis: 1998 update  

Microsoft Academic Search

Knowledge of the molecular genetic basis of resistance to antituberculous agents has advanced rapidly since we reviewed this topic 3 years ago. Virtually all isolates resistant to rifampin and related rifamycins have a mutation that alters the sequence of a 27-amino-acid region of the beta subunit of ribonucleic acid (RNA) polymerase. Resistance to isoniazid (INH) is more complex. Many resistant

S. Ramaswamy; J. M. Musser

1998-01-01

194

Chemo-sensitization of fungal pathogens to antimicrobial agents using benzaldehyde analogs  

Technology Transfer Automated Retrieval System (TEKTRAN)

Activity of conventional antifungal agents, fludioxonil, strobilurin and antimycinA, which target the oxidative and osmotic stress response systems, was elevated by co-application of certain analogs of benzaldehyde. Fungal tolerance to 2,3-dihydroxybenzaldehyde or 2,3-dihydroxybenzoic acid was foun...

195

Oregano essential oil-pectin edible films as anti-quorum sensing and food antimicrobial agents  

PubMed Central

Edible films can be used as carriers for antimicrobial compounds to assure food safety and quality; in addition, pathogenesis of food bacteria is related to a cell to cell communication mechanism called quorum sensing (QS). Oregano essential oil (OEO) has proved to be useful as food antimicrobial; however, its food applications can be compromised by the volatile character of its active constituents. Therefore, formulation of edible films containing OEO can be an alternative to improve its food usages. QS inhibitory activity of OEO and pectin-OEO films was evaluated using Chromobacterium violaceum as bacterial model. Additionally, antibacterial activity was tested against Escherichia coli O157:H7, Salmonella Choleraesuis, Staphylococcus aureus, and Listeria monocytogenes. OEO was effective to inhibit bacterial growth at MIC of 0.24 mg/mL for all tested bacteria and MBC of 0.24, 0.24, 0.48, and 0.24 mg/mL against E. coli O157:H7, S. Choleraesuis, S. aureus, and L. monocytogenes, respectively. Pectin-films incorporated with 36.1 and 25.9 mg/mL of OEO showed inhibition diameters of 16.3 and 15.2 mm for E. coli O157:H7; 18.1 and 24.2 mm for S. Choleraesuis; 20.8 and 20.3 mm for S. aureus; 21.3 and 19.3 mm for L. monocytogenes, respectively. Pectin-OEO film (15.7 mg/mL) was effective against E. coli O157:H7 (9.3 mm), S. aureus (9.7 mm), and L. monocytogenes (9.2 mm), but not for S. Choleraesuis. All concentrations of OEO (0.0156, 0.0312, 0.0625 and 0.125 mg/mL) and pectin-OEO films (15.7, 25.9 and 36.1 mg/mL) showed a significant anti-QS activity expressed as inhibition of violacein production by C. violaceum. Additionally, the application of pectin-OEO films was effective reducing total coliforms, yeast, and molds of shrimp and cucumber slices stored at 4°C during 15 d. These results demonstrated the potential of pectin films enriched with OEO as food related microorganisms and QS inhibitors. PMID:25566215

Alvarez, Maria V.; Ortega-Ramirez, Luis A.; Gutierrez-Pacheco, M. Melissa; Bernal-Mercado, A. Thalia; Rodriguez-Garcia, Isela; Gonzalez-Aguilar, Gustavo A.; Ponce, Alejandra; Moreira, Maria del R.; Roura, Sara I.; Ayala-Zavala, J. Fernando

2014-01-01

196

Udder pathogens and their resistance to antimicrobial agents in dairy cows in Estonia  

PubMed Central

Background The goal of this study was to estimate the distribution of udder pathogens and their antibiotic resistance in Estonia during the years 2007-2009. Methods The bacteriological findings reported in this study originate from quarter milk samples collected from cows on Estonian dairy farms that had clinical or subclinical mastitis. The samples were submitted by local veterinarians to the Estonian Veterinary and Food Laboratory during 2007-2009. Milk samples were examined by conventional bacteriology. In vitro antimicrobial susceptibility testing was performed with the disc diffusion test. Logistic regression with a random herd effect to control for clustering was used for statistical analysis. Results During the study period, 3058 clinical mastitis samples from 190 farms and 5146 subclinical mastitis samples from 274 farms were investigated. Positive results were found in 57% of the samples (4680 out of 8204), and the proportion did not differ according to year (p > 0.05). The proportion of bacteriologically negative samples was 22.3% and that of mixed growth was 20.6%. Streptococcus uberis (Str. uberis) was the bacterium isolated most frequently (18.4%) from cases of clinical mastitis, followed by Escherichia coli (E. coli) (15.9%) and Streptococcus agalactiae (Str. agalactiae) (11.9%). The bacteria that caused subclinical mastitis were mainly Staphylococcus aureus (S. aureus) (20%) and coagulase-negative staphylococci (CNS) (15.4%). The probability of isolating S. aureus from milk samples was significantly higher on farms that had fewer than 30 cows, when compared with farms that had more than 100 cows (p < 0.005). A significantly higher risk of Str. agalactiae infection was found on farms with more than 600 cows (p = 0.034) compared with smaller farms. The proportion of S. aureus and CNS isolates that were resistant to penicillin was 61.4% and 38.5%, respectively. Among the E. coli isolates, ampicillin, streptomycin and tetracycline resistance were observed in 24.3%, 15.6% and 13.5%, respectively. Conclusions This study showed that the main pathogens associated with clinical mastitis were Str. uberis and E. coli. Subclinical mastitis was caused mainly by S. aureus and CNS. The number of S. aureus and Str. agalactiae isolates depended on herd size. Antimicrobial resistance was highly prevalent, especially penicillin resistance in S. aureus and CNS. PMID:21299911

2011-01-01

197

Thin-layer chromatographic (TLC) separations and bioassays of plant extracts to identify antimicrobial compounds.  

PubMed

A common screen for plant antimicrobial compounds consists of separating plant extracts by paper or thin-layer chromatography (PC or TLC), exposing the chromatograms to microbial suspensions (e.g. fungi or bacteria in broth or agar), allowing time for the microbes to grow in a humid environment, and visualizing zones with no microbial growth. The effectiveness of this screening method, known as bioautography, depends on both the quality of the chromatographic separation and the care taken with microbial culture conditions. This paper describes standard protocols for TLC and contact bioautography with a novel application to amino acid-fermenting bacteria. The extract is separated on flexible (aluminum-backed) silica TLC plates, and bands are visualized under ultraviolet (UV) light. Zones are cut out and incubated face down onto agar inoculated with the test microorganism. Inhibitory bands are visualized by staining the agar plates with tetrazolium red. The method is applied to the separation of red clover (Trifolium pratense cv. Kenland) phenolic compounds and their screening for activity against Clostridium sticklandii, a hyper ammonia-producing bacterium (HAB) that is native to the bovine rumen. The TLC methods apply to many types of plant extracts and other bacterial species (aerobic or anaerobic), as well as fungi, can be used as test organisms if culture conditions are modified to fit the growth requirements of the species. PMID:24747583

Kagan, Isabelle A; Flythe, Michael D

2014-01-01

198

Effects of carbadox, a synthetic antimicrobial agent, on bile acid metabolism in the domestic pig  

SciTech Connect

Radiolabeled chenodeoxycholic acid (CDC) was infused into the hepatic portal vein (HP) and fluctuations of the plasma radioactivities of CDC and its metabolites were monitored in young unrestrained pigs. There was a significant difference in the plasma radioactivity between the morning and evening meals from both vena cava and portal vein plasma samples. To study the effects of an antimicrobial feed additive on bile acid metabolism, carbadox (CX) was added to a 19.5% corn-soybean ration and fed to young pigs. CX at 58 ppm affected apparent clearance of CDC from the HP blood. The plasma concentrations of the bile acids were higher in the animals fed CX. Plasma fluctuations of the bile acids in response to meals showed that the plasma bile acid concentrations following feeding at 1600 hours were greater than those following feeding at 0800 hours. The rate of excretion of the bile acids in the feces was increased and biological half-life of CDC decreased to 5.7 in the CX-fed pigs from 6.4 days in the controls. The feeding of CX did not significantly affect the activity of cholesterol 7..cap alpha..-hydroxylase (CH-7..cap alpha..), the rate-limiting enzyme for bile acid synthesis.

Tracy, J.D.

1985-01-01

199

Microwave assisted synthesis of some novel 2-pyrazoline derivatives as possible antimicrobial agents.  

PubMed

Some new [3-(4-phenyl)-5-phenyl-4,5-dihydropyrazol-1-yl](pyridine-4-yl)methanones and 3-substituted phenyl-5-substituted phenyl-4,5-dihydro-pyrazole-1-carbothioamides have been synthesized employing microwave techniques and evaluated for antimicrobial activity. Substituted acetophenones (1) were reacted with appropriately substituted benzaldehydes (2) in the presence of ethanol to furnish substituted chalcones (3a-f). These chalcones were further treated with isonicotinic acid hydrazide (INH) to afford substituted [3-(4-phenyl)-5-phenyl-4,5-dihydropyrazol-1-yl](pyridine-4-yl)methanones (4a-f). Reaction of these chalcones with thiosemicarbazide yielded substituted 3,5-diphenyl-4,5-dihydro-1H-pyrazole-1-carbothioamides (5a-f). The structures of newly synthesized compounds (4a-f) and (5a-f) have been confirmed by suitable spectroscopic techniques such as IR and 1H NMR. All the compounds were screened for their antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa and for antifungal activity against Candida albicans and Aspergillus niger The compounds exhibited moderate antibacterial and good antifungal activities. Compound 4b and 4d showed significant antifungal activity against A. niger and C. albicans, respectively. PMID:20210079

Chawla, Rakesh; Sahoo, Ujjwal; Arora, Anshu; Sharma, Prabodh Chander; Radhakrishnan, Vijayaraj

2010-01-01

200

Ruthenium (II) complexes of thiosemicarbazone: synthesis, biosensor applications and evaluation as antimicrobial agents.  

PubMed

A conformationally rigid half-sandwich organoruthenium (II) complex [(?(6)-p-cymene)RuClTSC(N-S)]Cl, (1) and carbonyl complex [Ru(CO)Cl(PPh3)2TSC(N-S)] (2) have been synthesized from the reaction of [{(?(6)-p-cymene)RuCl}2(?-Cl)2] and [Ru(H)(Cl)(CO)(PPh3)3] with thiophene-2-carboxaldehyde thiosemicarbazon (TSC) respectively and both novel ruthenium (II) complexes have been characterized by elemental analysis, FT-IR and NMR spectroscopy. The peripheral TSC in the complexes acts as an electrochemical coupling unit providing the ability to carry out electrochemical deposition (ED) and to form an electro-deposited film on a graphite electrode surface. The biosensing applicability of complexes 1 and 2 was investigated by using glucose oxidase (GOx) as a model enzyme. Electrochemical measurements at -0.9V versus Ag/AgCl electrode by following the ED Ru(II) reduction/oxidation due to from the enzyme activity, in the presence of glucose substrate. The designed biosensor showed a very good linearity for 0.01-0.5mM glucose. The in vitro antimicrobial activities of complexes 1 and 2 were also investigated against nine bacterial strains and one fungus by the disc diffusion test method. No activity was observed against the Gram-negative strains and fungus, whereas complex 1 showed moderate antibacterial activities against Gram-positive bacterial strains. PMID:25280673

Yildirim, Hatice; Guler, Emine; Yavuz, Murat; Ozturk, Nurdan; Kose Yaman, Pelin; Subasi, Elif; Sahin, Elif; Timur, Suna

2014-11-01

201

Novel mode of action of plant defense peptides - hevein-like antimicrobial peptides from wheat inhibit fungal metalloproteases.  

PubMed

The multilayered plant immune system relies on rapid recognition of pathogen-associated molecular patterns followed by activation of defense-related genes, resulting in the reinforcement of plant cell walls and the production of antimicrobial compounds. To suppress plant defense, fungi secrete effectors, including a recently discovered Zn-metalloproteinase from Fusarium verticillioides, named fungalysin Fv-cmp. This proteinase cleaves class IV chitinases, which are plant defense proteins that bind and degrade chitin of fungal cell walls. In this study, we investigated plant responses to such pathogen invasion, and discovered novel inhibitors of fungalysin. We produced several recombinant hevein-like antimicrobial peptides named wheat antimicrobial peptides (WAMPs) containing different amino acids (Ala, Lys, Glu, and Asn) at the nonconserved position 34. An additional Ser at the site of fungalysin proteolysis makes the peptides resistant to the protease. Moreover, an equal molar concentration of WAMP-1b or WAMP-2 to chitinase was sufficient to block the fungalysin activity, keeping the chitinase intact. Thus, WAMPs represent novel protease inhibitors that are active against fungal metalloproteases. According to in vitro antifungal assays WAMPs directly inhibited hyphal elongation, suggesting that fungalysin plays an important role in fungal development. A novel molecular mechanism of dynamic interplay between host defense molecules and fungal virulence factors is suggested. PMID:25154438

Slavokhotova, Anna A; Naumann, Todd A; Price, Neil P J; Rogozhin, Eugene A; Andreev, Yaroslav A; Vassilevski, Alexander A; Odintsova, Tatyana I

2014-10-01

202

Constitutive expression of transgenes encoding derivatives of the synthetic antimicrobial peptide BP100: impact on rice host plant fitness  

PubMed Central

Background The Biopeptide BP100 is a synthetic and strongly cationic ?-helical undecapeptide with high, specific antibacterial activity against economically important plant-pathogenic bacteria, and very low toxicity. It was selected from a library of synthetic peptides, along with other peptides with activities against relevant bacterial and fungal species. Expression of the BP100 series of peptides in plants is of major interest to establish disease-resistant plants and facilitate molecular farming. Specific challenges were the small length, peptide degradation by plant proteases and toxicity to the host plant. Here we approached the expression of the BP100 peptide series in plants using BP100 as a proof-of-concept. Results Our design considered up to three tandemly arranged BP100 units and peptide accumulation in the endoplasmic reticulum (ER), analyzing five BP100 derivatives. The ER retention sequence did not reduce the antimicrobial activity of chemically synthesized BP100 derivatives, making this strategy possible. Transformation with sequences encoding BP100 derivatives (bp100der) was over ten-fold less efficient than that of the hygromycin phosphotransferase (hptII) transgene. The BP100 direct tandems did not show higher antimicrobial activity than BP100, and genetically modified (GM) plants constitutively expressing them were not viable. In contrast, inverted repeats of BP100, whether or not elongated with a portion of a natural antimicrobial peptide (AMP), had higher antimicrobial activity, and fertile GM rice lines constitutively expressing bp100der were produced. These GM lines had increased resistance to the pathogens Dickeya chrysanthemi and Fusarium verticillioides, and tolerance to oxidative stress, with agronomic performance comparable to untransformed lines. Conclusions Constitutive expression of transgenes encoding short cationic ?-helical synthetic peptides can have a strong negative impact on rice fitness. However, GM plants expressing, for example, BP100 based on inverted repeats, have adequate agronomic performance and resistant phenotypes as a result of a complex equilibrium between bp100der toxicity to plant cells, antimicrobial activity and transgene-derived plant stress response. It is likely that these results can be extended to other peptides with similar characteristics. PMID:22947243

2012-01-01

203

Environment-selective synergism using self-assembling cytotoxic and antimicrobial agents.  

PubMed

Environment-selective synergistic toxicity using combinations of aldehydes and hydrazine derivatives was demonstrated in two different model systems in vitro. Combinations of 5-nitro-2-furaldehyde with semi-carbazide and of 2-hydrazinopyridine with pyridine-2-carboxaldehyde, which can react in situ to form antimicrobial hydrazones, demonstrated greater degrees of synergism against the intracellular pathogen, Salmonella typhimurium, at pH 5 relative to pH 7.4. Combinations are more selectively toxic at pH 5 (vs pH 7.4) than individual precursors and preformed hydrazone products because acid catalysis of hydrazone formation plays a role only for the combinations. A combination of decanal and N-amino, N'-octylguanidine (AOG) exhibited more pronounced synergistic cytolytic activity against erythrocytes in 0% serum than in 1% serum. Serum protein binding of decanal inhibited the formation of the more cytotoxic hydrazone, N-decylidenimino,N'-1-octylguanidine (DIOG), from the less cytotoxic AOG and decanal, and serum protein binding of DIOG prevented this cytotoxin from reaching the cell membrane. Because decanal binding cannot play a role in the cytotoxicity of preformed DIOG, it was less selective for cells in 0% serum than the combination of AOG and decanal. The pH 5 and 0% serum environments represent very simple models for macrophage phagolysosomal compartments and poorly vascularized solid tumor interiors respectively. If environment-selective synergism can be used as a basis for target-selective synergism in other in vitro model systems and in vivo, self-assembling combinations could provide a basis for rational introduction of target-selective synergism into chemotherapeutic drug design. PMID:3060122

Rideout, D; Jaworski, J; Dagnino, R

1988-12-01

204

Essential oil from blackcurrant buds as chemotaxonomy marker and antimicrobial agent.  

PubMed

Dormant buds are recognized as valuable side product of the blackcurrant cultivation. Four blackcurrant varieties cultivated in Serbia, i.e., Ben Sarek, Ometa, Ben Lomond, and Ben Nevis, were evaluated for the content, chemical composition, and antimicrobial activity of their bud essential oils. The oil yields of buds harvested during two different growth periods ranged from 1.2-2.0%, and the variety Ometa had the highest yield among the tested varieties. GC-FID and GC/MS analysis of the oils allowed the identification of eight main components, i.e., ?-pinene (1.6-5.4%), sabinene (1.9-38.4%), ?-car-3-ene (13.0-50.7%), ?-phellandrene (2.9-18.0%), terpinolene (6.6-11.9%), terpinen-4-ol (0.9-6.6%), ?-caryophyllene (3.8-10.4%), and ?-humulene (0.2-4.1%). In addition, the similarity degree of the essential-oil compositions of buds harvested from the upper and lower parts of the shrubs was investigated by hierarchical clustering. All essential oils originating from the same genotype were grouped in the same cluster, indicating the reliability of essential oils as chemotaxonomic markers. For more detailed chemotaxonomic investigations, the three compounds with the greatest variance were chosen, i.e., sabinene, ?-car-3-ene, and ?-phellandrene, which proved to be efficient for the variety distinction. Factor analysis showed that the essential-oil composition as chemotaxonomic marker in blackcurrants was more reliable for variety Ben Sarek than for variety Ben Nevis. Moreover, it was demonstrated that the essential oils had very strong inhibitory activity against all tested microorganisms. Fungi were more sensitive than bacteria; indeed their growth was completely inhibited at much lower concentrations. In comparison to commercial antibiotics, significantly lower concentrations of the oils were necessary for the complete inhibition of fungal growth. PMID:25146766

Ethor?evi?, Boban S; Pljevljakuši?, Ðor?evi? S; Savikin, Katarina P; Stevi?, Tatjana R; Bigovi?, Dubravka J

2014-08-01

205

Antagonism of Azole Activity against Candida albicans following Induction of Multidrug Resistance Genes by Selected Antimicrobial Agents  

PubMed Central

Antifungal azoles (e.g., fluconazole) are widely used for prophylaxis or treatment of Candida albicans infections in immunocompromised individuals, such as those with AIDS. These individuals are frequently treated with a variety of additional antimicrobial agents. Potential interactions between three azoles and 16 unrelated drugs (antiviral, antibacterial, antifungal, and antiprotozoal agents) were examined in vitro. Two compounds, tested at concentrations achievable in serum, demonstrated an antagonistic effect on azole activity against C. albicans. At fluconazole concentrations two to four times the 50% inhibitory concentration, C. albicans growth (relative to treatment with fluconazole alone) increased 3- to 18-fold in the presence of albendazole (2 ?g/ml) or sulfadiazine (50 ?g/ml). Antagonism (3- to 78-fold) of ketoconazole and itraconazole activity by these compounds was also observed. Since azole resistance has been correlated with overexpression of genes encoding efflux proteins, we hypothesized that antagonism results from drug-induced overexpression of these same genes. Indeed, brief incubation of C. albicans with albendazole or sulfadiazine resulted in a 3-to->10-fold increase in RNAs encoding multidrug transporter Cdr1p or Cdr2p. Zidovudine, trimethoprim, and isoniazid, which were not antagonistic with azoles, did not induce these RNAs. Fluphenazine, a known substrate for Cdr1p and Cdr2p, strongly induced their RNAs and, consistent with our hypothesis, strongly antagonized azole activity. Finally, antagonism was shown to require a functional Cdr1p. The possibility that azole activity against C. albicans is antagonized in vivo as well as in vitro in the presence of albendazole and sulfadiazine warrants investigation. Drug-induced overexpression of efflux proteins represents a new and potentially general mechanism for drug antagonism. PMID:10428921

Henry, Karl W.; Cruz, M. Cristina; Katiyar, Santosh K.; Edlind, Thomas D.

1999-01-01

206

Synthesis of 2,3,6-trideoxy sugar triazole hybrids as potential new broad spectrum antimicrobial agents.  

PubMed

Here, we describe a molecular hybridization inspired design and synthesis of novel 6-triazolyl 2,3,6-trideoxy sugars as promising new broad-spectrum antimicrobial agents using click chemistry in key step. These compounds showed MIC between 0.39 and 50 ?g/mL against different native and resistant bacteria and fungi with no toxicity. Among them, compound 29 was the most active molecule with MIC 0.78 ?g/mL against Staphylococcus aureus and Klebsiella pneumoniae and 3.12 ?g/mL against methicillin- and vancomycin-resistant S. aureus. Compound 26 was the most potent anti-fungal candidate with MIC 0.39 ?g/mL against Trichophyton mentagrophytes. Compound 46 was found to be promising with broad-spectrum activity against both bacterial and fungal strains. The bioinformatic studies involving bacteria's protein co-crystals prompted penicillin binding protein-2 as the most likely target of these compounds. PMID:24992075

Sharma, Smriti; Saquib, Mohammad; Verma, Saroj; Mishra, Nripendra N; Shukla, Praveen K; Srivastava, Ranjana; Prabhakar, Yenamandra S; Shaw, Arun K

2014-08-18

207

Synthesis of new N-substituted 5-arylidene-2,4-thiazolidinediones as anti-inflammatory and antimicrobial agents.  

PubMed

A novel series of 5-arylidene-2,4-thiazolidinediones (TZDs) 2a-p was synthesized from the condensation of 3-((2-phenylthiazol-4-yl)methyl)thiazolidine-2,4-dione with different benzaldehyde derivatives. All the structures were confirmed by their spectral (IR, ¹H NMR, ¹³C NMR and mass) and elemental analytical data. The new molecules were evaluated in vivo as anti-inflammatory agents in an acute experimental inflammation, evaluating the acute phase bone marrow response and phagocyte activity. All compounds, excepting one, reduced the absolute leukocytes count due to the lower neutrophil percentage. Phagocytary index was decreased by the same molecules, while only half of them reduced the phagocytary activity. The effect was superior to meloxicam, the reference anti-inflammatory drug, for the majority of the TZD derivatives. The new molecules were also investigated for their antimicrobial properties on Gram-positive and Gram-negative bacteria and one fungal strain. Two compounds (2e and 2n) manifested growth inhibition capacity on all the tested strains. PMID:23666636

Nastas?, Cristina; Tiperciuc, Brîndu?a; Pârvu, Alina; Duma, Mihaela; Ionu?, Ioana; Oniga, Ovidiu

2013-06-01

208

Engineered plant biomass particles coated with biological agents  

DOEpatents

Plant biomass particles coated with a biological agent such as a bacterium or seed, characterized by a length dimension (L) aligned substantially parallel to a grain direction and defining a substantially uniform distance along the grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) normal to W and L. In particular, the L.times.H dimensions define a pair of substantially parallel side surfaces characterized by substantially intact longitudinally arrayed fibers, the W.times.H dimensions define a pair of substantially parallel end surfaces characterized by crosscut fibers and end checking between fibers, and the L.times.W dimensions define a pair of substantially parallel top and bottom surfaces.

Dooley, James H.; Lanning, David N.

2014-06-24

209

Engineered plant biomass particles coated with bioactive agents  

DOEpatents

Plant biomass particles coated with a bioactive agent such as a fertilizer or pesticide, characterized by a length dimension (L) aligned substantially parallel to a grain direction and defining a substantially uniform distance along the grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) normal to W and L. In particular, the L.times.H dimensions define a pair of substantially parallel side surfaces characterized by substantially intact longitudinally arrayed fibers, the W.times.H dimensions define a pair of substantially parallel end surfaces characterized by crosscut fibers and end checking between fibers, and the L.times.W dimensions define a pair of substantially parallel top and bottom surfaces.

Dooley, James H; Lanning, David N

2013-07-30

210

Plant phytochemicals: potential anticancer agents against gastric cancer.  

PubMed

Isothiocyanates (ITCs) are plant phytochemicals derived from vegetables consumed by human. ITCs comprise potent anti-carcinogenic agents of which the consumption has been linked to a reduced risk of cancer at several locations in the body. However, the studies on coping with gastric cancer remain unsatisfied. In the present review, ITCs are discussed in this context as ITCs may target gastric tumorigenesis at multiple levels. ITCs are taken up in the stomach, exposing mucosal and muscle layer cells as well as affecting Helicobacter pylori residing in the stomach. The natural and potent anti-cancer ITCs from vegetables have a great potential against gastric cancer, a disease in need of new treatment or preventive modalities. PMID:24929966

Overby, Anders; Zhao, Chun-Mei; Chen, Duan

2014-12-01

211

Antimicrobial and cytotoxic activity of Ferula gummosa plant essential oil compared to NaOCl and CHX: a preliminary in vitro study  

PubMed Central

Objectives The usage of medicinal plants as natural antimicrobial agents has grown in many fields including dental medicine. The aim of this in vitro study was three-fold: (i) to determine the chemical compositions of the Ferula gummosa essential oil (FGEO), (ii) to compare the antimicrobial efficacy of the oil with sodium hypochlorite (NaOCl) and chlorhexidine (CHX), (iii) to assess the toxic behavior of FGEO in different concentrations compared to 5% NaOCl and 0.2% CHX. Materials and Methods Gas chromatography/mass spectrometry (GC/MS) was used to determine the chemical compositions of the oil. The disk diffusion method and a broth micro-dilution susceptibility assay were exploited to assess the antimicrobial efficacy against Enterococcus faecalis, Staphylococcus aureus, Streptococcus mitis, and Candida albicans. The cytocompatibility of the FGEO was assessed on L929 fibroblasts, and compared to that of NaOCl and CHX. Results Twenty-seven constituents were recognized in FGEO. The major component of the oil was ?-pinene (51.83%). All three irrigants significantly inhibited the growth of all examined microorganisms compared to the negative control group. FGEO at 50 µg/mL was effective in lower concentration against Enterococcus faecalis than 5% NaOCl and 0.2% CHX, and was also more potent than 0.2% CHX against Candida albicans and Staphylococcus aureus. FGEO was a cytocompatible solution, and had significantly lower toxicity compared to 5% NaOCl and 0.2% CHX. Conclusions FGEO showed a promising biological potency as a root canal disinfectant. More investigations are required on the effectiveness of this oil on intracanal bacterial biofilms. PMID:25671213

Abbaszadegan, Abbas; Gholami, Ahmad; Saliminasab, Mina; Kazemi, Aboozar; Moein, Mahmood Reza

2015-01-01

212

New Type of Antimicrobial Protein Produced by the Plant Pathogen Clavibacter michiganensis subsp. michiganensis  

PubMed Central

It has previously been shown that the tomato pathogen Clavibacter michiganensis subsp. michiganensis secretes a 14-kDa protein, C. michiganensis subsp. michiganensis AMP-I (CmmAMP-I), that inhibits growth of Clavibacter michiganensis subsp. sepedonicus, the causal agent of bacterial ring rot of potato. Using sequences obtained from tryptic fragments, we have identified the gene encoding CmmAMP-I and we have recombinantly produced the protein with an N-terminal intein tag. The gene sequence showed that CmmAMP-I contains a typical N-terminal signal peptide for Sec-dependent secretion. The recombinant protein was highly active, with 50% growth inhibition (IC50) of approximately 10 pmol, but was not toxic to potato leaves or tubers. CmmAMP-I does not resemble any known protein and thus represents a completely new type of bacteriocin. Due to its high antimicrobial activity and its very narrow inhibitory spectrum, CmmAMP-1 may be of interest in combating potato ring rot disease. PMID:23851100

Liu, Zhanliang; Ma, Ping; Holtsmark, Ingrid; Skaugen, Morten; Eijsink, Vincent G. H.

2013-01-01

213

Antimicrobial and antioxidative activity of extracts and essential oils of Myrtus communis L.  

PubMed

Since synthetic antimicrobial agents and food additives can cause a number of adverse effects, there is a growing interest from consumers in ingredients from natural sources. Medicinal plants, such as Myrtus communis L. are a source of new compounds which can be used in both the food industry and for medical purposes, primarily as antimicrobial agents. In this review, the characteristics of myrtle essential oils and extracts are summarized, with particular attention to their chemical composition, biological activities and potential applications. PMID:24291016

Aleksic, Verica; Knezevic, Petar

2014-04-01

214

Antimicrobial resistance in commensal Escherichia coli isolated from muscle foods as related to the veterinary use of antimicrobial agents in food-producing animals in Austria.  

PubMed

Controversy exists on veterinary drug application in food animal production and the relevance for human health of antimicrobial resistant commensals isolated from food. The aim of this study was to analyze antimicrobial resistance in Escherichia coli isolated from retail meat of various animal species (including wild roe deer) in Austria. Our results were analyzed taking into consideration the current practices of Austrian veterinarians with regard to their use of antibiotic drugs during pig, poultry, and beef production. Resistant isolates were found most often in pork (76%) followed by poultry (63%) and beef (40%). On wild deer carcasses purchased from Austrian hunters only one isolate was found to be resistant. The latter indicates that antimicrobial resistance is not yet an environmental problem in animals living in the wild. The common use of tetracyclines in veterinary medication in various animal species is clearly reflected in the incidence of antimicrobial resistant isolates in commensal E. coli. The intensive use of fluoroquinolones in poultry could explain the high numbers of nalidixic acid resistant isolates found on poultry meat. Our findings partly explain the impact of veterinary drug application on the resistance development of E. coli isolated from meat. PMID:17227214

Mayrhofer, Sigrid; Paulsen, Peter; Smulders, Frans J M; Hilbert, Friederike

2006-01-01

215

Potential applications of plant based derivatives as fat replacers, antioxidants and antimicrobials in fresh and processed meat products.  

PubMed

Growing concern about diet and health has led to development of healthier food products. In general consumer perception towards the intake of meat and meat products is unhealthy because it may increase the risk of diseases like cardiovascular diseases, obesity and cancer, because of its high fat content (especially saturated fat) and added synthetic antioxidants and antimicrobials. Addition of plant derivatives having antioxidant components including vitamins A, C and E, minerals, polyphenols, flavanoids and terpenoids in meat products may decrease the risk of several degenerative diseases. To change consumer attitudes towards meat consumption, the meat industry is undergoing major transformations by addition of nonmeat ingredients as animal fat replacers, natural antioxidants and antimicrobials, preferably derived from plant sources. PMID:24845336

Hygreeva, Desugari; Pandey, M C; Radhakrishna, K

2014-09-01

216

Evaluating the toxic effect of an antimicrobial agent on single bacterial cells with optical tweezers  

PubMed Central

We implement an optical tweezers technique to assess the effects of chemical agents on single bacterial cells. As a proof of principle, the viability of a trapped Escherichia coli bacterium is determined by monitoring its flagellar motility in the presence of varying concentrations of ethyl alcohol. We show that the “killing time” of the bacterium can be effectively identified from the correlation statistics of the positional time series recorded from the trap, while direct quantification from the time series or associated power spectra is intractable. Our results, which minimize the lethal effects of bacterial photodamage, are consistent with previous reports of ethanol toxicity that used conventional culture-based methods. This approach can be adapted to study other pairwise combinations of drugs and motile bacteria, especially to measure the response times of single cells with better precision. PMID:25657879

Samadi, Akbar; Zhang, Chensong; Chen, Joseph; Reihani, S. N. S.; Chen, Zhigang

2014-01-01

217

Evaluating the toxic effect of an antimicrobial agent on single bacterial cells with optical tweezers.  

PubMed

We implement an optical tweezers technique to assess the effects of chemical agents on single bacterial cells. As a proof of principle, the viability of a trapped Escherichia coli bacterium is determined by monitoring its flagellar motility in the presence of varying concentrations of ethyl alcohol. We show that the "killing time" of the bacterium can be effectively identified from the correlation statistics of the positional time series recorded from the trap, while direct quantification from the time series or associated power spectra is intractable. Our results, which minimize the lethal effects of bacterial photodamage, are consistent with previous reports of ethanol toxicity that used conventional culture-based methods. This approach can be adapted to study other pairwise combinations of drugs and motile bacteria, especially to measure the response times of single cells with better precision. PMID:25657879

Samadi, Akbar; Zhang, Chensong; Chen, Joseph; Reihani, S N S; Chen, Zhigang

2015-01-01

218

Bactericidal effects of antimicrobial agents on epithelial cell-associated Pseudomonas aeruginosa.  

PubMed

It is not clear whether antipseudomonal agents can kill cell-associated bacteria within a short time. Madin-Darby canine kidney (MDCK) and A549 cells were infected with Pseudomonas aeruginosa ATCC 27853 and PAO1 and the bactericidal activity of ceftazidime, imipenem, meropenem, gentamicin, and ciprofloxacin against the organisms was investigated. In both MDCK and A549 cells, ?-lactams could not kill epithelial cell-associated bacteria within 2 h. Gentamicin at concentrations ?32 ?g/ml killed more than 99% of epithelial cell-associated bacteria. Ciprofloxacin at 0.5 ?g/ml killed more than 99.9% of MDCK cell-associated bacteria. Ciprofloxacin has the strongest and most rapid bactericidal activity against epithelial cell-associated bacteria, which may be explained by the combination of potent in-vitro bactericidal activity and high penetration ability into epithelial cells. PMID:22116462

Hirakata, Yoichi; Yano, Hisakazu; Arai, Kazuaki; Kitagawa, Miho; Hatta, Masumitsu; Kunishima, Hiroyuki; Kaku, Mitsuo

2012-06-01

219

The use of resazurin as a novel antimicrobial agent against Francisella tularensis  

PubMed Central

The highly infectious and deadly pathogen, Francisella tularensis, is classified by the CDC as a Category A bioterrorism agent. Inhalation of a single bacterium results in an acute pneumonia with a 30–60% mortality rate without treatment. Due to the prevalence of antibiotic resistance, there is a strong need for new types of antibacterial drugs. Resazurin is commonly used to measure bacterial and eukaryotic cell viability through its reduction to the fluorescent product resorufin. When tested on various bacterial taxa at the recommended concentration of 44 ?M, a potent bactericidal effect was observed against various Francisella and Neisseria species, including the human pathogens type A F. tularensis (Schu S4) and N. gonorrhoeae. As low as 4.4 ?M resazurin was sufficient for a 10-fold reduction in F. tularensis growth. In broth culture, resazurin was reduced to resorufin by F. tularensis. Resorufin also suppressed the growth of F. tularensis suggesting that this compound is the biologically active form responsible for decreasing the viability of F. tularensis LVS bacteria. Replication of F. tularensis in primary human macrophages and non-phagocytic cells was abolished following treatment with 44 ?M resazurin indicating this compound could be an effective therapy for tularemia in vivo. PMID:24367766

Schmitt, Deanna M.; O'Dee, Dawn M.; Cowan, Brianna N.; Birch, James W.-M.; Mazzella, Leanne K.; Nau, Gerard J.; Horzempa, Joseph

2013-01-01

220

Evaluation of antimicrobial and cytotoxic activities of plant extracts from southern Minas Gerais cerrado.  

PubMed

The antimicrobial activity of plant hidroethanolic extracts on bacteria Gram positive, Gram negative, yeasts, Mycobacterium tuberculosis H37 and Mycobacterium bovis was evaluated by using the technique of Agar diffusion and microdilution in broth. Among the extracts evaluated by Agar diffusion, the extract of Bidens pilosa leaf presented the most expressive average of haloes of growth inhibition to the microorganisms, followed by the extract of B. pilosa flower, of Eugenia pyriformis' leaf and seed, of Plinia cauliflora leaf which statistically presented the same average of haloes inhibitory formation on bacteria Gram positive, Gram negative and yeasts. The extracts of Heliconia rostrata did not present activity. Mycobacterium tuberculosis H37 and Mycobacterium bovis (BCG) appeared resistant to all the extracts. The susceptibility profile of Candida albicans and Saccharomyces cerevisiae fungi were compared to one another and to the Gram positive Bacillus subtilis, Enterococcus faecalis and the Gram negative Salmonella typhimurium bacteria (p > 0.05). The evaluation of cytotoxicity was carried out on C6-36 larvae cells of the Aedes albopictus mosquito. The extracts of stem and flower of Heliconia rostrata, leaf and stem of Plinia cauliflora, seed of Anonna crassiflora and stem, flower and root of B. pilosa did not present toxicity in the analyzed concentrations. The highest rates of selectivity appeared in the extracts of stem of A. crassiflora and flower of B. pilosa to Staphylococcus aureus, presenting potential for future studies about a new drug development. PMID:24553603

Chavasco, Juliana Moscardini; Prado E Feliphe, Bárbara Helena Muniz; Cerdeira, Claudio Daniel; Leandro, Fabrício Damasceno; Coelho, Luiz Felipe Leomil; Silva, Jéferson Junior da; Chavasco, Jorge Kleber; Dias, Amanda Latercia Tranches

2014-01-01

221

Chemical composition and antimicrobial activity of the essential oil from the edible aromatic plant Aristolochia delavayi.  

PubMed

The essential oil obtained by hydrodistillation from the aerial parts of Aristolochia delavayi Franch. (Aristolochiaceae), a unique edible aromatic plant consumed by the Nakhi (Naxi) people in Yunnan, China, was investigated using GC/MS analysis. In total, 95 components, representing more than 95% of the oil composition, were identified, and the main constituents found were (E)-dec-2-enal (52.0%), (E)-dodec-2-enal (6.8%), dodecanal (3.35%), heptanal (2.88%), and decanal (2.63%). The essential oil showed strong inhibitory activity (96% reduction) of the production of bacterial volatile sulfide compounds (VSC) by Klebsiella pneumoniae, an effect that was comparable with that of the reference compound citral (91% reduction). Moreover, the antimicrobial activity of the essential oil and the isolated major compound against eight bacterial and six fungal strains were evaluated. The essential oil showed significant antibacterial activity against Providencia stuartii and Escherichia coli, with minimal inhibitory concentrations (MIC) ranging from 3.9 to 62.5 ?g/ml. The oil also showed strong inhibitory activity against the fungal strains Trichophyton ajelloi, Trichophyton terrestre, Candida glabrata, Candida guilliermondii, and Cryptococcus neoformans, with MIC values ranging from 3.9 to 31.25 ?g/ml, while (E)-dec-2-enal presented a lower antifungal activity than the essential oil. PMID:24243612

Li, Zhi-Jian; Njateng, Guy S S; He, Wen-Jia; Zhang, Hong-Xia; Gu, Jian-Long; Chen, Shan-Na; Du, Zhi-Zhi

2013-11-01

222

Role of Antibiofilm-Antimicrobial Agents in Control of Device-Related Infections  

PubMed Central

Objectives To assess the effects of N-acetylcysteine (NAC) on organism viability in planktonic and biofilm phases, biofilm thickness, and extracellular polysaccharide content. Methods We performed time-kill curves and broth macrodilution assays of bacterial and fungal clinical isolates with varying concentrations of NAC. We also created in-vitro bacterial biofilms, incubated them with NAC or control, and then stained with propidium iodide and FITC-labelled concanavalin A. We measured biofilm thickness, number of non-viable cells, and fluorescent intensity as a marker of extracellular matrix via a confocal laser scanning microscope. All experiments were conducted in triplicate. Tested organisms included methicillin-sensitive and - resistant Staphylococcus aureus (MSSA, MRSA), S. epidermidis, vancomycin-resistant Enterococcus faecalis (VRE), Pseudomonas aeruginosa, Enterobacter cloacae, Klebsiella pneumoniae, Candida albicans and C. krusei. Results NAC 80 mg/ml was uniformly bactericidal (>99.9% reduction) against all tested bacteria with no recoverable organisms after 30 minutes of incubation, but was fungistatic against candida species. Minimum inhibitory and bactericidal concentrations of NAC ranged from 5–10 mg/ml. Biofilm thickness was significantly decreased in NAC-treated biofilms for all organisms except VRE. The number of non-viable cells in NAC-treated Gram-positive biofilms was increased (p<0.05 for MRSA and VRE). NAC-treated Gram-negative biofilms had scant cellularity and lacked complex 3-dimensional structures that were characteristic of controls. Fluorescent intensity was similar in the experimental and control arms. Conclusions NAC is bactericidal against clinically relevant and drug-resistant bacteria and also leads to biofilm disruption. NAC has the potential for use as a novel agent for prevention or treatment of biofilm-related infections. PMID:22094553

Aslam, Saima; Darouiche, Rabih O.

2011-01-01

223

Antimicrobial susceptibility pattern of bacterial isolates from wound infection and their sensitivity to alternative topical agents at Jimma University Specialized Hospital, South-West Ethiopia  

PubMed Central

Background Wound infection is one of the health problems that are caused and aggravated by the invasion of pathogenic organisms. Information on local pathogens and sensitivity to antimicrobial agents, and topical agents like acetic acid is crucial for successful treatment of wounds. Objectives To determine antimicrobial susceptibility pattern of bacterial isolates from wound infection and their sensitivity to alternative topical agents at Jimma University Specialized Hospital. Methods A cross sectional study was conducted among patients with wound infection visiting Jimma University Specialized Hospital, from May to September 2013. Wound swab was collected using sterile cotton swabs and processed for bacterial isolation and susceptibility testing to antimicrobial agents, acetic acid, hydrogen peroxide and dabkin solution following standard bacteriological techniques. Biochemical tests were done to identify the species of the organisms. Sensitivity testing was done using Kirby- Baur disk diffusion method. Minimum inhibitory and bactericidal concentration was done using tube dilution method. Results In this study 145 bacterial isolates were recovered from 150 specimens showing an isolation rate of 87.3%. The predominant bacteria isolated from the infected wounds were Staphylococcus aureus 47 (32.4%) followed by Escherichia coli 29 (20%), Proteus species 23 (16%), Coagulase negative Staphylococci 21 (14.5%), Klebsiella pneumoniae 14 (10%) and Pseudomonas aeruginosa 11 (8%). All isolates showed high frequency of resistance to ampicillin, penicillin, cephalothin and tetracycline. The overall multiple drug resistance patterns were found to be 85%. Acetic acid (0.5%), Dabkin solution (1%) and 3% hydrogen peroxide were bactericidal to all isolated bacteria and lethal effect observed when applied for 10 minutes. Conclusions On in vitro sensitivity testing, ampicillin, penicillin, cephalothin and tetracycline were the least effective. Gentamicin, norfloxacin, ciprofloxacin, vancomycin and amikacin were the most effective antibiotics. Acetic acid (0.5%), dabkin solution (1%) and H2O2 (3%) were bactericidal to all isolates. PMID:24731394

2014-01-01

224

Rapid inactivation of Salmonella Enteritidis on shell eggs by plant-derived antimicrobials.  

PubMed

Salmonella Enteritidis is a common foodborne pathogen transmitted to humans largely by consumption of contaminated eggs. The external surface of eggs becomes contaminated with Salmonella Enteritidis from various sources on farms, the main sources being hens' droppings and contaminated litter. Therefore, effective egg surface disinfection is critical to reduce pathogens on eggs and potentially control egg-borne disease outbreaks. This study investigated the efficacy of GRAS (generally recognized as safe) status, plant-derived antimicrobials (PDA), namely trans-cinnamaldehyde (TC), carvacrol (CR), and eugenol (EUG), as an antimicrobial wash for rapidly killing Salmonella Enteritidis on shell eggs in the presence or absence of chicken droppings. White-shelled eggs inoculated with a 5-strain mixture of nalidixic acid (NA) resistant Salmonella Enteritidis (8.0 log cfu/mL) were washed in sterile deionized water containing each PDA (0.0, 0.25, 0.5, or 0.75%) or chlorine (200 mg/kg) at 32 or 42°C for 30 s, 3 min, or 5 min. Approximately 6.0 log cfu/mL of Salmonella Enteritidis was recovered from inoculated and unwashed eggs. The wash water control and chlorine control decreased Salmonella Enteritidis on eggs by only 2.0 log cfu/mL even after washing for 5 min. The PDA were highly effective in killing Salmonella Enteritidis on eggs compared with controls (P < 0.05). All treatments containing CR and EUG reduced Salmonella Enteritidis to undetectable levels as rapidly as within 30 s of washing, whereas TC (0.75%) completely inactivated Salmonella Enteritidis on eggs washed at 42°C for 30 s (P < 0.05). No Salmonella Enteritidis was detected in any PDA or chlorine wash solution; however, substantial pathogen populations (~4.0 log cfu/mL) survived in the antibacterial-free control wash water (P < 0.05). The CR and EUG were also able to eliminate Salmonella Enteritidis on eggs to undetectable levels in the presence of 3% chicken droppings at 32°C (P < 0.05). This study demonstrates that PDA could effectively be used as a wash treatment to reduce Salmonella Enteritidis on shell eggs. Sensory and quality studies of PDA-washed eggs need to be conducted before recommending their use. PMID:24235233

Upadhyaya, Indu; Upadhyay, Abhinav; Kollanoor-Johny, Anup; Baskaran, Sangeetha Ananda; Mooyottu, Shankumar; Darre, Michael J; Venkitanarayanan, Kumar

2013-12-01

225

Phytochemical screening and evaluation of Monechma ciliatum (black mahlab) seed extracts as antimicrobial agents  

PubMed Central

Objective: Tribes in Nubia Mountains regions of Sudan used Monechma ciliatum seeds for common cold and other chest allergic conditions as a traditional medicine. The aim of this paper is to validate this traditional practice scientifically. Materials and Methods: Monechma ciliatum seeds were screened for major phytochemical groups using standard methods. Different extracts were bioassayed in- vitro for their bioactivity to inhibit the growth of pathogenic bacteria and fungi. Results: Phytochemical screening results showed the presence of flavonoids, tannins, triterpens, and anthraquinones. Staphylococcus aureus was found to be sensitive to both water extract with zones of inhibition 22 – 26 mm at concentrations of 50 and 100mg/ml and ethanol extract 17 mm at concentration of 100 mg/ml. The growth of Klebsiella pneumoniae was inhibited by ethanol extract with zones of inhibition equal to 16, 26, and 33 mm at concentrations of 50, 100, and 150 mg/ml, respectively. Pseudomonas aeruginosa was insensitive to all extracts used. Similarly, all used fungi were found to be insensitive to extracts used. The minimum inhibitory concentrations of the extracts against microorganisms were ranged from 12.5 to 25 mg/ml. Conclusion: The findings of the current study support the traditional uses of the plant's seed in the therapy of respiratory tract infections caused by Staphylococcus aureus and Klebsiella pneumoniae. PMID:25050266

Ahmed Oshi, Murtada; Mohmmed Abdelkarim, Abdelkarim

2013-01-01

226

Approaches towards the synthesis of a novel class of 2-amino-5-arylazonicotinate, pyridazinone and pyrido[2,3-d]pyrimidine derivatives as potent antimicrobial agents  

PubMed Central

Background Despite significant progresses in antimicrobial therapy, infectious diseases caused by bacteria and fungi remain a major worldwide health problem because of the rapid development of resistance to existing antimicrobial drugs. Therefore, there is a constant need for new antimicrobial agents. There are a large number of heterocyclic derivatives containing nitrogen atoms that possess a broad spectrum of biological activities including pyridine and pyridazine, which are two of the most important heterocycles in medicinal chemistry. Results The reaction of 3-oxo-2-arylhydrazonopropanals 2 with ethyl cyanoacetate and malononitrile 3a,b has led to the formation of 2-amino-5-arylazo-6-aryl substituted nicotinates 8a-k as sole isolable products when the aryl group in the arylazo moiety was substituted with an electron-withdrawing group like Cl, Br, NO2. The pyridazinones 10 were formed from the same reaction when the arylazo moiety was phenyl or phenyl substituted with an electron-donating group. The 2-aminoazonicotinates 8 were condensed with DMF-DMA to afford the amidines 13a,b, which then were cyclized to afford the targeted pyrido[2,3-d]pyrimidine derivatives 15a,b, respectively. The structures of all new substances prepared in this investigation were determined by using X-ray crystallographic analysis and spectroscopic methods. Most of the synthesized compounds were tested and evaluated as antimicrobial agents and the results indicated that many of the obtained compounds exhibited high antimicrobial activity comparable to ampicillin, which was used as the reference compound. Conclusion A general rule for the synthesis of 2-amino-5-arylazo-6-aryl substituted nicotinic acid and pyridazinone was established using 3-oxo-2-arylhydrazonopropanal as a precursor. Moreover, a novel route to pyrido[2,3-d]pyrimidine was achieved. Most of the synthesized compounds were found to exhibit strong inhibitory effects on the growth of Gram-positive bacteria especially Bacillus subtilis. Compounds 1a, 8a-h, 10a-c, 15b and 16 showed a broad spectrum of antimicrobial activity against B. subtilis. PMID:23867062

2013-01-01

227

In Vitro Model of Colonization Resistance by the Enteric Microbiota: Effects of Antimicrobial Agents Used in Food-Producing Animals  

Microsoft Academic Search

A bioassay was developed to measure the minimum concentration of an antimicrobial drug that disrupts the colonization resistance mediated by model human intestinal microbiota against Salmonella invasion of Caco-2 intestinal cells. The bioassay was used to measure the minimum disruptive concentrations (MDCs) of drugs used in animal agriculture. The MDCs varied from 0.125 g\\/ml for some broad-spectrum antimicrobial drugs (e.g.,

R. Doug Wagner; Shemedia J. Johnson; Carl E. Cerniglia

2008-01-01

228

Antimicrobial Use and Antimicrobial Resistance: A Population Perspective  

Microsoft Academic Search

The need to stem the growing problem of antimicrobial resistance has prompted multiple, sometimes con- flicting, calls for changes in the use of antimicrobial agents. One source of disagreement concerns the major mechanisms by which antibiotics select resistant strains. For infections like tuberculosis, in which resistance can emerge in treated hosts through mutation, prevention of antimicrobial resistance in individ- ual

Marc Lipsitch; Matthew H. Samore

2002-01-01

229

Minimum inhibitory concentrations for selected antimicrobial agents against organisms isolated from the mammary glands of dairy heifers in New Zealand and Denmark.  

PubMed

Minimum inhibitory concentrations were determined for selected antimicrobial agents against 872 bacteria isolated from intramammary infections in heifers in New Zealand (n = 401) and Denmark (n = 471). These values were reported in micrograms per milliliters. Antimicrobial agents tested against isolates from New Zealand were penicillin, cloxacillin, cephapirin, ceftiofur, novobiocin, enrofloxacin, erythromycin, and pirlimycin. The minimum inhibitory concentrations that inhibit 90% of the strains tested for these antimicrobial agents with Staphylococcus aureus were 4.0, 0.5, 0.5, 2.0, 1.0, 0.25, 0.5, and 1.0, respectively. The minimum inhibitory concentration values that inhibit 90% of the strains tested against the Staphylococcus spp. ranged from 0.5 to 1.0 for all antimicrobics. The minimum inhibitory concentrations against streptococci were < or = 0.06, 0.5, 0.13, 0.13, 4.0, 1.0, 0.13, and < or = 0.06, respectively. Antimicrobial agents tested against isolates from Denmark included penicillin, ampicillin, oxacillin, cephalothin, ceftiofur, penicillin plus novobiocin, erythromycin, and pirlimycin. Against S. aureus, the minimum inhibitory concentrations were 0.13, 0.5, 0.5, 0.5, 1.0, 0.25, 0.5, and 0.5, respectively. The minimum inhibitory concentrations against Staphylococcus spp. were 0.25, 0.25, 0.5, 0.5, 1.0, < or = 0.06, 0.13, 1.0, and 0.5, respectively. The minimum inhibitory concentrations against the streptococci were < or = 0.06, 0.13, 0.5, 0.5, 1.0, < or = 0.06, 0.13, 0.5, and 0.5, respectively. Minimum inhibitory concentration values for staphylococci from New Zealand and Denmark were similar to values reported for US isolates. Streptococci from New Zealand and Denmark had lower minimum inhibitory concentration values than did US isolates. Only ceftiofur and enrofloxacin were active against the Gram-negative bacilli. PMID:9532511

Salmon, S A; Watts, J L; Aarestrup, F M; Pankey, J W; Yancey, R J

1998-02-01

230

An investigation of the 6a g inner valence orbital electron density of the antimicrobial agent diacetyl by binary (e,2e) spectroscopy  

NASA Astrophysics Data System (ADS)

We report here the first measurements of the complete valence shell binding energy spectra and the 6a g inner valence orbital momentum profile of the antimicrobial agent diacetyl, also known as 2,3-butanedione (CH 3COCOCH 3), using a high-resolution binary (e,2e) electron momentum spectroscopy, at an impact energy of 1200 eV plus the binding energy, and using symmetric non-coplanar kinematics. The experimental momentum profile of the 6a g inner valence orbital is compared with Hartree-Fock (HF) and density functional theory (DFT) calculations. The experimental measurement is quite well described by the HF and DFT calculations.

Su, G. L.; Ren, X. G.; Zhang, S. F.; Ning, C. G.; Zhou, H.; Li, B.; Li, G. Q.; Deng, J. K.; Wang, Y.; Zheng, Y.

2004-02-01

231

Ethnomedicinal and phytochemical review of Pakistani medicinal plants used as antibacterial agents against Escherichia coli  

PubMed Central

Medicinal plants have always been part of human culture and have the potential to cure different diseases caused by microorganisms. In Pakistan, biologists are mainly focusing on plantsantimicrobial activities against Escherichia coli due to its increasing resistance to antibiotics. In total, extracts from 34 ethnomedicinally valuable Pakistani plants were reported for in-vitro anti-E. coli activities. Mostly methanolic extracts of medicinal plants were used in different studies, which have shown comparatively higher inhibitory activities against E. coli than n-hexane and aqueous extracts. It has been found that increasing concentration (mg/ml) of methanolic extract can significantly increase (p plants are extracted in solvents others than above, which should also be tested against E. coli. Moreover, medicinal plant species must be fully explored phytochemically, which may lead to the development of new drugs. PMID:25135359

2014-01-01

232

Ethnomedicinal and phytochemical review of Pakistani medicinal plants used as antibacterial agents against Escherichia coli.  

PubMed

Medicinal plants have always been part of human culture and have the potential to cure different diseases caused by microorganisms. In Pakistan, biologists are mainly focusing on plants' antimicrobial activities against Escherichia coli due to its increasing resistance to antibiotics. In total, extracts from 34 ethnomedicinally valuable Pakistani plants were reported for in-vitro anti-E. coli activities. Mostly methanolic extracts of medicinal plants were used in different studies, which have shown comparatively higher inhibitory activities against E. coli than n-hexane and aqueous extracts. It has been found that increasing concentration (mg/ml) of methanolic extract can significantly increase (p<0.01) anti-E. coli activities. Not all medicinal plants are extracted in solvents others than above, which should also be tested against E. coli. Moreover, medicinal plant species must be fully explored phytochemically, which may lead to the development of new drugs. PMID:25135359

Adnan, Muhammad; Bibi, Roqaia; Mussarat, Sakina; Tariq, Akash; Shinwari, Zabta Khan

2014-01-01

233

Studies of the in vitro cytotoxic, antioxidant, lipase inhibitory and antimicrobial activities of selected Thai medicinal plants  

PubMed Central

Background Traditional folk medicinal plants have recently become popular and are widely used for primary health care. Since Thailand has a great diversity of indigenous (medicinal) plant species, this research investigated 52 traditionally used species of Thai medicinal plants for their in vitro cytotoxic, antioxidant, lipase inhibitory and antimicrobial activities. Methods The 55 dried samples, derived from the medicinally used parts of the 52 plant species were sequentially extracted by hexane, dichloromethane, ethanol and water. These 220 extracts were then screened for in vitro (i) cytotoxicity against four cell lines, derived from human lung (A549), breast (MDA-MB-231), cervical (KB3-1) and colon (SW480) cancers, using the MTT cytotoxicity assay; (ii) antioxidant activity, analyzed by measuring the scavenging activity of DPPH radicals; (iii) lipase inhibitory activity, determined from the hydrolytic reaction of p-nitrophenyllaurate with pancreatic lipase; and (iv) antimicrobial activity against three Gram-positive and two Gram-negative bacteria species plus one strain of yeast using the disc-diffusion method and determination of the minimum inhibitory concentration by the broth micro-dilution assay. Results The crude dichloromethane and/or ethanol extracts from four plant species showed an effective in vitro cytotoxic activity against the human cancer cell lines that was broadly similar to that of the specific chemotherapy drugs (etoposide, doxorubicin, vinblastine and oxaliplatin). In particular, this is the first report of the strong in vitro cytotoxic activity of Bauhinia strychnifolia vines. The tested tissue parts of only six plant species (Allium sativum, Cocoloba uvifera, Dolichandrone spathacea, Lumnitzera littorea, Sonneratia alba and Sonneratia caseolaris) showed promising potential antioxidant activity, whereas lipase inhibitory activity was only found in the ethanol extract from Coscinum fenestratum and this was weak at 17-fold lower than Orlistat, a known lipase inhibitor. The highest antimicrobial activity was observed in the extracts from S. alba and S. caseolaris against Pseudomonas aeruginosa and Candida albicans, respectively. Conclusion The Thai medicinal plant B. strychnifolia is first reported to exert strong in vitro cytotoxic activities against human cancer cell lines and warrants further enrichment and characterization. The broad spectrum of the biological activities from the studied plant extracts can be applied as the guideline for the selection of Thai medicinal plant species for further pharmacological and phytochemical investigations. PMID:23145786

2012-01-01

234

Elicitors and priming agents initiate plant defense responses Paul W. Pare 1,  

E-print Network

chemical defenses when translocated to plant tissue. The fatty acid conjugate volicitin has provenJA ­ met- hyl jasmonate; PAL ­ phenylalanine ammonia lyase; PGPR ­ plant growth promoting rhizobacteriaReview Elicitors and priming agents initiate plant defense responses Paul W. Pare´ 1, *, Mohamed A

Paré, Paul W.

235

Synthesis and evaluation of (Z)-2,3-diphenylacrylonitrile analogs as anti-cancer and anti-microbial agents.  

PubMed

In the present study, a series of (Z)-2,3-diphenylacrylonitrile analogs were synthesized and then evaluated in terms of their cytotoxic activities against four human cancer cell lines, e.g. lung cancer (A549), ovarian cancer (SK-OV-3), skin cancer (SK-MEL-2), and colon cancer (HCT15), as well as anti-microbial activities against three microbes, e.g. Staphylococcus aureus, Salmonella typhi, and Aspergillus niger. The title compounds were synthesized by Knoevenagel condensation reaction of benzyl cyanide or p-nitrobenzyl cyanide with substituted benzaldehydes in good yields. Most of the compounds exhibited significant suppressive activities against the growth of all cancer cell lines. Compound 3c was most active in inhibiting the growth of A549, SK-OV-3, SK-MEL-2, and HCT15 cells lines with IC50 values of 0.57, 0.14, 0.65, and 0.34 mg/mL, respectively, followed by compounds 3f, 3i, and 3h. Compound 3c exhibited 2.4 times greater cytotoxic activity against HCT15 cells, whereas it showed similar potency against SK-OV-3 cells to that of the standard anti-cancer agent doxorubicin. Structure-activity relationship study revealed that electron-donating groups at the para-position of phenyl ring B were more favorable for improved cytotoxic activity, whereas the presence of electron-withdrawing groups was unfavorable compare to unsubstituted acrylonitrile. An optimal electron density on phenyl ring A of (Z)-2,3-diphenylacrylonitrile analogs was crucial for their cytotoxic activities against human cancer cell lines used in the present study. Qualitative structure-cytotoxic activity relationships were studied using physicochemical parameters; a good correlation between calculated polar surface area (PSA), a lipophobic parameter, and cytotoxic activity was found. Moreover, all compounds showed significant anti-bacterial activities against S. typhi, whereas compound 3k showed potent inhibition against both S. aureus and S. typhi bacterial strains. PMID:24113364

Alam, Mohammad Sayed; Nam, Young-Joo; Lee, Dong-Ung

2013-11-01

236

Synthesis of silver nanoparticles using Dioscorea bulbifera tuber extract and evaluation of its synergistic potential in combination with antimicrobial agents  

PubMed Central

Background Development of an environmentally benign process for the synthesis of silver nanomaterials is an important aspect of current nanotechnology research. Among the 600 species of the genus Dioscorea, Dioscorea bulbifera has profound therapeutic applications due to its unique phytochemistry. In this paper, we report on the rapid synthesis of silver nanoparticles by reduction of aqueous Ag+ ions using D. bulbifera tuber extract. Methods and results Phytochemical analysis revealed that D. bulbifera tuber extract is rich in flavonoid, phenolics, reducing sugars, starch, diosgenin, ascorbic acid, and citric acid. The biosynthesis process was quite fast, and silver nanoparticles were formed within 5 hours. Ultraviolet-visible absorption spectroscopy, transmission electron microscopy, high-resolution transmission electron microscopy, energy dispersive spectroscopy, and x-ray diffraction confirmed reduction of the Ag+ ions. Varied morphology of the bioreduced silver nanoparticles included spheres, triangles, and hexagons. Optimization studies revealed that the maximum rate of synthesis could be achieved with 0.7 mM AgNO3 solution at 50°C in 5 hours. The resulting silver nanoparticles were found to possess potent antibacterial activity against both Gram-negative and Gram-positive bacteria. Beta-lactam (piperacillin) and macrolide (eryth-romycin) antibiotics showed a 3.6-fold and 3-fold increase, respectively, in combination with silver nanoparticles selectively against multidrug-resistant Acinetobacter baumannii. Notable synergy was seen between silver nanoparticles and chloramphenicol or vancomycin against Pseudomonas aeruginosa, and was supported by a 4.9-fold and 4.2-fold increase in zone diameter, respectively. Similarly, we found a maximum 11.8-fold increase in zone diameter of streptomycin when combined with silver nanoparticles against E. coli, providing strong evidence for the synergistic action of a combination of antibiotics and silver nanoparticles. Conclusion This is the first report on the synthesis of silver nanoparticles using D. bulbifera tuber extract followed by an estimation of its synergistic potential for enhancement of the antibacterial activity of broad spectrum antimicrobial agents. PMID:22334779

Ghosh, Sougata; Patil, Sumersing; Ahire, Mehul; Kitture, Rohini; Kale, Sangeeta; Pardesi, Karishma; Cameotra, Swaranjit S; Bellare, Jayesh; Dhavale, Dilip D; Jabgunde, Amit; Chopade, Balu A

2012-01-01

237

Anti-phytopathogen potential of endophytic actinobacteria isolated from tomato plants (Lycopersicon esculentum) in southern Brazil, and characterization of Streptomyces sp. R18(6), a potential biocontrol agent.  

PubMed

Tomato plants (Lycopersicon esculentum) are highly susceptible to phytopathogen attack. The resulting intensive application of pesticides on tomato crops can affect the environment and health of humans and animals. The objective of this study was to select potential biocontrol agents among actinobacteria from tomato plants, in a search for alternative phytopathogen control. We evaluated 70 endophytic actinobacteria isolated from tomato plants in southern Brazil, testing their antimicrobial activity, siderophore production, indoleacetic acid production, and phosphate solubility. The actinomycete isolate with the highest antimicrobial potential was selected using the agar-well diffusion method, in order to optimize conditions for the production of compounds with antimicrobial activity. For this study, six growth media (starch casein-SC, ISP2, Bennett's, Sahin, Czapek-Dox, and TSB), three temperatures (25 degrees C, 30 degrees C, and 35 degrees C) and different pH were tested. Of the actinobacteria tested, 88.6% showed antimicrobial activity against at least one phytopathogen, 72.1% showed a positive reaction for indoleacetic acid production, 86.8% produced siderophores and 16.2% showed a positive reaction for phosphate solubility. Isolate R18(6) was selected due to its antagonistic activity against all phytopathogenic microorganisms tested in this study. The best conditions for production were observed in the SC medium, at 30 degrees C and pH 7.0. The isolate R18(6) showed close biochemical and genetic similarity to Streptomyces pluricolorescens. PMID:20542109

de Oliveira, Margaroni Fialho; da Silva, Mariana Germano; Van Der Sand, Sueli T

2010-09-01

238

Antimicrobial activity of plant essential oils against bacterial and fungal species involved in food poisoning and/or food decay.  

PubMed

The currative properties of aromatic and medicinal plants have been recognized since ancient times and, more recently, the antimicrobial activity of plant essential oils has been used in several applications, including food preservation. The purpose of this study was to create directly comparable, quantitative data on the antimicrobial activity of some plant essential oils prepared in the National Institute of Research-Development for Chemistry and Petrochemistry, Bucharest to be used for the further development of food packaging technology, based on their antibacterial and antifungal activity. The essential oils extracted from thyme (Thymus vulgaris L.), basil (Ocimum basilicum L.), coriander (Coriandrum sativum L.), rosemary (Rosmarinus officinalis L.), sage (Salvia officinalis L.), fennel (Foeniculum vulgare L.), spearmint (Mentha spicata L.) and carraway (Carum carvi L.) were investigated for their antimicrobial activity against eleven different bacterial and three fungal strains belonging to species reported to be involved in food poisoning and/or food decay: S. aureus ATCC 25923, S. aureus ATCC 6538, S. aureus ATCC 25913, E. coli ATCC 25922, E. coli ATCC 35218, Salmonella enterica serovar Enteritidis Cantacuzino Institute Culture Collection (CICC) 10878, Listeria monocytogenes ATCC 19112, Bacillus cereus CIP 5127, Bacillus cereus ATCC 11778, Candida albicans ATCC 10231, Aspergillus niger ATCC 16404, Penicillium spp. CICC 251 and two E. coli and Salmonella enterica serovar Enteritidis clinical isolates. The majority of the tested essential oils exibited considerable inhibitory capacity against all the organisms tested, as supported by growth inhibition zone diameters, MICs and MBC's. Thyme, coriander and basil oils proved the best antibacterial activity, while thyme and spearmint oils better inhibited the fungal species. PMID:21462837

Lixandru, Brîndu?a-Elena; Dr?cea, Nicoleta Olgu?a; Dragomirescu, Cristiana Cerasella; Dr?gulescu, Elena Carmina; Coldea, Ileana Lumini?a; Anton, Liliana; Dobre, Elena; Rovinaru, Camelia; Codi??, Irina

2010-01-01

239

Evaluation of minimum inhibitory and minimum bactericidal concentration of nano-silver base inorganic anti-microbial agent (Novaron®) against streptococcus mutans  

PubMed Central

Objective: We attempted to find the possibility of determining the minimum inhibitory concentration and minimum bactericidal concentration needed for nano-silver base inorganic anti-microbial agent (Novaron® AG 300, AG 1100) against Streptococcus mutans in vitro using broth dilution assay. Materials and Methods: An ampoule of freeze-dried S. mutans NCTC reference strain was revived, and the colony-forming units (CFU) were calculated. The MIC and MBC was determined by broth dilution assay using different concentrations of Novaron® AG 300 and Novaron® AG 1100 against 1 × 105 CFU/ml of S. mutans. Results: The MIC and MBC of Novaron® AG 300 and Novaron® AG 1100 against S. mutans were found to be 40 ?g/ml. Conclusions: Novaron® has anti-bacterial effect against S. mutans. Further studies are needed to explore the applicability of these silver-supported anti- microbial agents in clinical dentistry. PMID:23293483

Holla, Goda; Yeluri, Ramakrishna; Munshi, Autar Krishen

2012-01-01

240

Design and synthesis of biquinolone-isoniazid hybrids as a new class of antitubercular and antimicrobial agents.  

PubMed

Twenty four biquinolone-isoniazid hybrids were designed based on molecular hybridization technique and synthesized via multicomponent cyclocondensation (MCC) approach. All the newly synthesized compounds were screened for their antimicrobial and antitubercular activities. The brine shrimp bioassay was carried out to study the cytotoxicity of the synthesized compounds. Hybrids 7f (MIC = 25 ?g/mL); 7a, 7e and 7m (MIC = 50 ?g/mL); 7g, 7h and 7k (MIC = 62.5 ?g/mL) exhibited excellent antimicrobial activity as compared with standard drugs. Hybrids 7l and 7j displayed 99% inhibition against Mycobacterium tuberculosis bacteria with better LC50 values 35.39 and 34.59 ?g/mL, respectively. These results indicate that the synthesized compounds can act as leads for the development of newer antimicrobial and antitubercular compounds. PMID:23747804

Jardosh, Hardik H; Patel, Manish P

2013-07-01

241

Efficacy of the novel topical antimicrobial agent PXL150 in a mouse model of surgical site infections.  

PubMed

Antimicrobial peptides have recently emerged as a promising new group to be evaluated in the therapeutic intervention of infectious diseases. This study evaluated the anti-infectious effect of the short, synthetic, broad-spectrum antimicrobial peptide PXL150 in a mouse model of staphylococcal surgical site infections. We found that administration of PXL150, formulated in an aqueous solution or in a hydroxypropyl cellulose gel, significantly reduced the bacterial counts in the wound compared with placebo treatment, warranting further investigations of the potential of this peptide as a novel local treatment of microbial infections. PMID:24590479

Håkansson, Joakim; Björn, Camilla; Lindgren, Kerstin; Sjöström, Emma; Sjöstrand, Veronika; Mahlapuu, Margit

2014-05-01

242

Efficacy of the Novel Topical Antimicrobial Agent PXL150 in a Mouse Model of Surgical Site Infections  

PubMed Central

Antimicrobial peptides have recently emerged as a promising new group to be evaluated in the therapeutic intervention of infectious diseases. This study evaluated the anti-infectious effect of the short, synthetic, broad-spectrum antimicrobial peptide PXL150 in a mouse model of staphylococcal surgical site infections. We found that administration of PXL150, formulated in an aqueous solution or in a hydroxypropyl cellulose gel, significantly reduced the bacterial counts in the wound compared with placebo treatment, warranting further investigations of the potential of this peptide as a novel local treatment of microbial infections. PMID:24590479

Håkansson, Joakim; Björn, Camilla; Lindgren, Kerstin; Sjöström, Emma; Sjöstrand, Veronika

2014-01-01

243

Quantitative susceptibility of Streptococcus suis strains isolated from diseased pigs in seven European countries to antimicrobial agents licensed in veterinary medicine.  

PubMed

The susceptibility of Streptococcus suis strains (n=384) isolated from diseased pigs in seven European countries to 10 antimicrobial agents was determined. For that purpose a microbroth dilution method was used according to CLSI recommendations. The following antimicrobial agents were tested: ceftiofur, cefquinome, enrofloxacin, florfenicol, gentamicin, penicillin, spectinomycin, tetracycline, tilmicosin and trimethoprim/sulphamethoxazole. Using breakpoints established by CLSI for veterinary pathogens, all strains were susceptible to ceftiofur, florfenicol, enrofloxacin and penicillin. MIC-90 values of these antibiotics were < or = 0.03, 0.5, 2 and < or = 0.13 microg/mL, respectively. A low degree of resistance was observed for gentamicin (1.3%), spectinomycin (3.6%) and trimethoprim/sulphamethoxazole (6.0%). MIC-90 values of these antibiotics were 8, 16 and 2 microg/mL, respectively. A high level of resistance was observed for tetracycline (75.1%). A MIC-90 value of 64 microg/mL was found for this antibiotic. Serotype-associated differences in MIC-90 values were observed for tetracycline, tilmicosin and trimethoprim/suphamethoxazole. PMID:16387456

Wisselink, Henk J; Veldman, Kees T; Van den Eede, Chris; Salmon, Sarah A; Mevius, Dik J

2006-03-10

244

TiO2 nanotube arrays deposited on Ti substrate by anodic oxidation and their potential as a long-term drug delivery system for antimicrobial agents  

NASA Astrophysics Data System (ADS)

Nanotube arrays on medical titanium surfaces were fabricated by two different anodization methods and their potential for storage and release of antimicrobial substances was evaluated. The treatment of the Ti surfaces in fluoride containing electrolytes on water as well as on polyethylene glycol basis led to the formation of TiO2 nanotubes with up to 6.54 ?m length and average diameters of up to 160 nm. Drug release experiments with the model antibiotic vancomycin and with antibacterial silver ions showed that the increased surface area of the anodized samples enabled them to be loaded with up to 450% more active agent than the untreated Ti surfaces. Significant surface-dependent differences in the release kinetics of vancomycin were observed. In comparison to surfaces anodized in an aqueous electrolyte, the release of the antibiotic from surfaces anodized in an electrolyte based on ethylene glycol was significantly retarded, with a release of noticeable amounts over a period of more than 300 days. Loading of nanotube surfaces fabricated in aqueous electrolyte with silver ions revealed increased amounts of adsorbed silver by up to 230%, while the release kinetics showed significant differences in comparison to untreated Ti. It was concluded that nanotube arrays on favored medical implant materials have a high potential for loading with antimicrobial agents and also provide the possibility of tailored release kinetics by variation of anodization parameters.

Moseke, Claus; Hage, Felix; Vorndran, Elke; Gbureck, Uwe

2012-05-01

245

Antimicrobial activity of crude extracts from plant parts and corresponding calli of Bixa orellana L.  

PubMed

Ethanol extracts from the different parts of B. orellana showed differential antimicrobial activity. It was found that the extracts of in vitro leaves showed maximum activity against Bacillus pumilus followed by the extracts from the roots and hypocotyls. The callus derived from different explants too showed antimicrobial activity. The leaf callus showed maximum activity. The zone of inhibition for the diluted extracts of in vitro hypocotyls and roots and their corresponding calli showed minimum zone of inhibition at concentration 24 mg/ml, whereas the diluted extract of in vitro leaves and leaf derived callus showed minimum zone of inhibition at 16 mg/ml. PMID:12974400

Castello, Marie-Claire; Phatak, Anita; Chandra, Naresh; Sharon, Madhuri

2002-12-01

246

Antimicrobial peptides from ranid frogs: taxonomic and phylogenetic markers and a potential source of new therapeutic agents  

Microsoft Academic Search

Granular glands in the skins of frogs of the genus Rana, a widely distributed group with over 250 species, synthesize and secrete a remarkably diverse array of peptides with antimicrobial activity that are believed to have arisen as a result of multiple gene duplication events. Almost without exception, these components are hydrophobic, cationic and form an amphipathic ?-helix in a

J. Michael Conlon; Jolanta Kolodziejek; Norbert Nowotny

2004-01-01

247

Antimicrobial Peptides  

PubMed Central

The rapid increase in drug-resistant infections has presented a serious challenge to antimicrobial therapies. The failure of the most potent antibiotics to kill “superbugs” emphasizes the urgent need to develop other control agents. Here we review the history and new development of antimicrobial peptides (AMPs), a growing class of natural and synthetic peptides with a wide spectrum of targets including viruses, bacteria, fungi, and parasites. We summarize the major types of AMPs, their modes of action, and the common mechanisms of AMP resistance. In addition, we discuss the principles for designing effective AMPs and the potential of using AMPs to control biofilms (multicellular structures of bacteria embedded in extracellular matrixes) and persister cells (dormant phenotypic variants of bacterial cells that are highly tolerant to antibiotics). PMID:24287494

Bahar, Ali Adem; Ren, Dacheng

2013-01-01

248

Evaluation of the in vitro anticancer, antimicrobial and antioxidant activities of some Yemeni plants used in folk medicine.  

PubMed

The present research study deals with the evaluation of sixty four methanolic and aqueous extracts of thirty Yemeni plants used in traditional medicine for their in vitro antiproliferative activity against three human cancer cell lines in a microtiter plate assay based on cellular staining with crystal violet, for their antimicrobial activity against antibiotic susceptible three Gram-positive, three Gram-negative bacterial and one fungal stains and three multiresistant Staphylococcus strains by the agar diffusion method and the determination of MIC against three Gram-positive bacteria with the broth micro-dilution assay, as well as for their antioxidant activity using the DPPH radical scavenging method. Furthermore the chemical composition of the methanolic extracts was determined by using chromatographic methods. As a result of this work, 12 Yemeni herbs namely Centaurothamus maximus, Costus arabicus, Cupressus sempervirens, Dichrocephala integrifolia, Euphorbia schimperi, Gomphocarpus fruticosus, Kanahia laniflora, Meriandera benghalensis, Pulicaria inuloides, Solanum glabratum, Tarconanthus camphoratus and Vernonia leopoldii demonstrated a noteworthy growth inhibitory effect against all cancer cell lines with IC50 values <50 microg/ml. Pronounced antimicrobial activity was observed only against Gram-positive bacteria among them multiresistant bacteria with inhibition zones >15 mm and MIC values <500 microg/ml, by 9 plants especially Centaurothamus maximus, Cupressus sempervirens, Enicostemma verticillare, Meriandera benghalensis, Nepeta deflersiana, Pulicaria inuloides, Tarconanthus camphoratus, Teucrium yemense and Vernonia leopoldii. Moreover, the methanolic extracts of Cupressus sempervirens, Meriandera benghalensis, Pulicaria inuloides and Rhus retinorrhaea showed a remarkable radical scavenging effect at low concentrations. PMID:19435146

Mothana, R A A; Gruenert, R; Bednarski, P J; Lindequist, U

2009-04-01

249

ANTIMICROBIAL SUSCEPTIBILITY OF LACTOBACILLUS SPECIES ISOLATED FROM FUEL-ETHANOL PLANTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bacterial contamination of commercial fermentation cultures is a common and costly problem to the fuel ethanol industry. Antimicrobials such as tetracycline (TET), penicillin G (PEN), and virginiamycin (VIR) are frequently used to control contamination but there are little data available on the sus...

250

Ecological and mechanistic insights into the direct and indirect antimicrobial properties of Bacillus subtilis lipopeptides on plant pathogens.  

PubMed

Members of the genus Bacillus produce a wide variety of antimicrobial compounds. Cyclic lipopeptides (CLP) produced by Bacillus subtilis strains have been shown to protect host plants from a numbers of pathogens. The representative families of these CLP (surfactins, fengycins, and iturins) share a polypeptide ring linked to a lipid tail of varying length. CLP provide plant protection through a variety of unique mechanisms. Members of the surfactin and fengycin families elicit induced systemic resistance in certain host plants, and they also function by directly affecting the biological membranes of bacterial and fungal pathogens, mainly resulting in membrane pore formation. Specific pore forming mechanisms differ between CLP families, causing differential activities. CLP also may aid in enhanced B. subtilis colonization of the plant environment in addition to potentially preventing the adhesion of competitive microorganisms. Several recent studies have highlighted the control of plant pathogens by CLP-producing B. subtilis strains. Strong ecological advantages through multifaceted activities of CLP provide these strains with immense promise in controlling pathogens in a variety of plant ecosystems. PMID:23888387

Falardeau, J; Wise, C; Novitsky, L; Avis, T J

2013-07-01

251

Evidence of VX nerve agent use from contaminated white mustard plants.  

PubMed

The Chemical Weapons Convention prohibits the development, production, acquisition, stockpiling, retention, transfer or use of chemical weapons by Member States. Verification of compliance and investigations into allegations of use require accurate detection of chemical warfare agents (CWAs) and their degradation products. Detection of CWAs such as organophosphorus nerve agents in the environment relies mainly upon the analysis of soil. We now present a method for the detection of the nerve agent VX and its hydrolysis products by gas chromatography and liquid chromatography mass spectrometry of ethanol extracts of contaminated white mustard plants (Sinapis alba) which retained the compounds of interest for up to 45 days. VX is hydrolysed by the plants to ethyl methylphosphonic acid and then to methylphosphonic acid. The utility of white mustard as a nerve agent detector and remediator of nerve agent-polluted sites is discussed. The work described will help deter the employment of VX in conflict. PMID:25104906

Gravett, Matthew R; Hopkins, Farrha B; Self, Adam J; Webb, Andrew J; Timperley, Christopher M; Baker, Matthew J

2014-08-01

252

Plant Polyphenolics as Anti-Invasive Cancer Agents  

Microsoft Academic Search

Because invasion is, either directly or via metastasis formation, the main cause of death in cancer patients, development of ef- ficient anti-invasive agents is an important research challenge. We have established a screening program for potentially anti-invasive compounds. The assay is based on organotypic confronting cultures between human invasive cancer cells and a fragment of normal tissue in three dimensions.

V. S. Parmar; M. E. Bracke; B. W. A. Vanhoecke; L. Derycke; S. Bolca; S. Possemiers; A. Heyerick; C. V. Stevens; D. D. Keukeleire; H. T. Depypere; W. Verstraete; C. A. Williams; S. T. McKenna; S. Tomar; D. Sharma; A. K. Prasad; A. L. DePass

2008-01-01

253

EFFECT OF A FLYASH CONDITIONING AGENT ON POWER PLANT EMISSIONS  

EPA Science Inventory

The report gives results of a study undertaken as a preliminary program to provide data on the environmental effects of a chemical flyash conditioning agent (Apollo Chemicals conditioner LPA 402A). Both the emissions due to the chemical and its effect on electrostatic precipitato...

254

ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, Jan. 2011, p. 417420 Vol. 55, No. 1 0066-4804/11/$12.00 doi:10.1128/AAC.01080-10  

E-print Network

and the antimicrobial peptide pexiganan. Antimicrobial peptides (AMPs) (1) are ubiquitously found in nature peptoids excellent candidates to mimic antimicrobial peptides. Lipopeptides such as daptomycin of antimicrobial peptides. Poly- myxin B (34) and trichogin (27) possess fatty acid moieties that are known

Barron, Annelise E.

255

Survey of Susceptibilities of Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis Isolates to 26 Antimicrobial Agents: a Prospective U.S. Study  

PubMed Central

An antimicrobial susceptibility surveillance study of Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis isolates was performed during the winter of 1996–1997 in order to determine their susceptibilities to 5 fluoroquinolones and 21 other antimicrobial agents. Broth microdilution MICs were determined for 2,752 isolates from 51 U.S. medical centers. Of the 1,276 S. pneumoniae isolates, 64% were susceptible, 17% were intermediate, and 19% were highly resistant to penicillin. On the basis of the MICs at which 90% of isolates are inhibited and modal MICs, the hierarchy of the five fluoroquinolones from most to least active was grepafloxacin > sparfloxacin > levofloxacin = ciprofloxacin > ofloxacin. For S. pneumoniae isolates for which penicillin MICs were elevated, the MICs of the cephalosporins, macrolides, clindamycin, tetracycline, and trimethoprim-sulfamethoxazole were also elevated, but the MICs of the fluoroquinolones, vancomycin, and rifampin were not. The prevalence of penicillin-susceptible pneumococci varied by U.S. Bureau of the Census region (range, 44% in the East South Central region to 75% in the Pacific region). In addition, S. pneumoniae isolates from blood were significantly more susceptible to penicillin than those from respiratory, ear, or eye specimens, and pneumococci from patients ?2 years old were significantly more resistant to penicillin than those from older patients (by chi-square analysis, P < 0.05). ?-Lactamase was produced by 35% of H. influenzae isolates and 93% of M. catarrhalis isolates, resulting in increased MICs of amoxicillin and certain cephalosporins. We noted that the antimicrobial resistance patterns of S. pneumoniae isolates, which correlate with the penicillin susceptibility phenotype, vary by site of infection, age group of the patient, and geographic source of the isolate. PMID:10543737

Thornsberry, C.; Ogilvie, P. T.; Holley, H. P.; Sahm, D. F.

1999-01-01

256

Antimicrobial Evaluaiton of Novel Fatty Acid Derivatives and Other Natural Antimicrobials  

Microsoft Academic Search

The food industry has shown increased interest for novel natural antimicrobials due to consumer demand for foods with fewer synthetic additives, increased safety, quality and shelf-life. Concurrently, the emergence of drug resistant bacteria substantiates the need for newer antimicrobial agents. Alternative strategies include the use of novel antimicrobials, such as fatty acid derivatives, essential oils and bacteriocins, with proven antimicrobial

Patricia Nobmann

2009-01-01

257

[Comparison of antimicrobial use density (AUD) of carbapenem antibacterial agents and investigation of the drug susceptibility of Pseudomonas aeruginosa in 3 hospitals in southern Ibaraki Prefecture, Japan].  

PubMed

The optimal use of anti-Pseudomonas agents is an important issue in the prevention of a tolerance against Pseudomonas aeruginosa. We evaluated the effect of antimicrobial use density (AUD) of carbapenem on drug susceptibility. The AUD of the four carbapenems, imipenem (IPM/CS), panipenem (PAPM/BP), meropenem (MEPM), and biapenem (BIPM), was examined at three hospitals in Ibaraki Prefecture, between April and September 2004. The AUD was calculated using the Defined Daily Doses (DDD) methodology developed by the WHO. A drug susceptibility test was conducted on the 306 Pseudomonas aeruginosa strains randomly collected from clinical specimens at the three hospitals between September and December 2004. In accordance with the standards set by the Clinical and Laboratory Standards Institute (CLSI), minimal inhibitory concentration (MIC) was measured using the broth microdilution method. The results showed that the AUD of carbapenem at the three hospitals tended to be higher than that in other research results in Japan. At one of the three hospitals, the AUD of the PAPM was remarkably high compared to the other carbapenems. Furthermore, P. aeruginosa strains collected at this hospital showed a low susceptibility to carbapenem, and many highly tolerant strains were also observed in this hospital. In order to maintain the susceptibility of Pseudomonas aeruginosa to carbapenem, the overall extent of carbapenem use must be optimal. The use of antimicrobial drugs should be controlled properly at each hospital, in order to prevent excessive use of PAPM/BP from being used over a long period of time. PMID:18709988

Oishi, Tsuyoshi; Hitomi, Shigemi; Kamoshita, Masaharu; Fukue, Hidetaka; Kawahata, Daisuke; Fukutake, Katsuyuki

2008-07-01

258

Major change in the use of antibiotics following a national programme: Swedish Strategic Programme for the Rational Use of Antimicrobial Agents and Surveillance of Resistance (STRAMA).  

PubMed

In order to reduce inappropriate use of antibiotics and to counteract the increase in antimicrobial resistance in community-acquired and nosocomial infections, a national project was initiated in Sweden in 1994: the Swedish Strategic Programme for the Rational Use of Antimicrobial Agents and Surveillance of Resistance. In the first years the project focused on inappropriate prescribing of antibiotics to children with respiratory tract infections and on the surveillance of resistance in pneumococci. Statistics on antibiotic sales on a national and county level and for different age-groups were studied. Between 1993 and 1997 antibiotic prescribing was reduced by 22%, from 16.3 to 13.0 defined daily doses (DDD) per 1000 inhabitants/d. The reduction was most pronounced for children, 0-6-y-old, from 15.7 to 9.7 DDD/1000 children/d. Macrolides and amoxicillin/co-amoxyclav decreased most. There were large variations in antibiotic sales in different counties, and a decrease was also noted in counties starting from a low level. In the county with the highest sales in 1993, antibiotic prescribing to children was reduced by 40%. The national frequency of penicillin-non-susceptible pneumococci (MIC > or =0.1 mg/l) has not increased during the 1990s and the increasing incidence in southern Sweden seems to have been curtailed. During the period that the project has been running, a major change in the use of antibiotics, especially for pre-school children, has been achieved. PMID:10447331

Mölstad, S; Cars, O

1999-01-01

259

Characterization of ?-carrageenan films incorporated plant essential oils with improved antimicrobial activity.  

PubMed

Antioxidant and antimicrobial kappa-carrageenan-based films containing different concentrations of Zataria multiflora Boiss (ZEO) and Mentha pulegium (MEO) essential oils were developed, and their water vapor permeability (WVP), optical, microstructure, antioxidant and antimicrobial properties were characterized. ZEO and MEO decreased the WVP of the emulsified films; for example, 3% ZEO reduced WVP by around 80%. Increasing the content of ZEO or MEO from 1% to 3% (v/v) increased values for elongation at break from 37.43% to 44.74% and from 36.09% to 41.25% respectively. Carrageenan-composite films were less resistant to breakage, more flexible and more opaque with lower gloss. These properties were related to the film's microstructure as analyzed by atomic force microscopy and scanning electron microscopy. ZEO affected the antioxidant properties of the films more markedly than MEO, e.g., ZEO containing films showed DPPH radical scavenging of 80.6% which were two-fold higher than those having MEO. The films' antimicrobial activities were increased by incorporating essential oils, particularly ZEO, which were more effective against the bacteria in the direct-contact method than a vapor phase. S. aureus was found to be the most sensitive bacterium to either ZEO or MEO, followed by B. cereus and E. coli. A highest inhibition zone of 544.05 mm(2) was observed for S. aureus around the films incorporated with 3% (v/v) ZEO. The total inhibitory zone of 3% (v/v) MEO formulated films was 20.43 for S. typhimurium and 10.15 mm(2) for P. aeruginosa. These results revealed that ZEO and MEO have good potential to be incorporated into ?-carrageenan to make antimicrobial and antioxidant edible films for food applications. PMID:24299814

Shojaee-Aliabadi, Saeedeh; Hosseini, Hedayat; Mohammadifar, Mohammad Amin; Mohammadi, Abdorreza; Ghasemlou, Mehran; Hosseini, Seyede Marzieh; Khaksar, Ramin

2014-01-30

260

Natural products of plant origin as anticancer agents.  

PubMed

Natural products have been used as effective remedies for the treatment of various ailments. Numerous plant products in the form of decoction, tincture, tablets and capsules have been clinically used for the treatment of different kinds of cancer. This review covers some of the important plants with clinically proven anticancer activity, including Catharanthus roseus, Podophyllum peltatum, Taxus brevifolia, Camptothecin acuminata, Cephalotaxus harringtonia, Viscum album, Onchrosia elliptica, Annona bullata, Asmina triloba and Rhizoma zedoariae. Synthetic analogues in some cases have also been prepared to improve the efficacy and decrease the side effects of parent compounds. The modes of action of clinically used drugs are also delineated. PMID:12806432

Ram, V J; Kumari, S

2001-10-01

261

Antimicrobial Prophylaxis in Adults  

PubMed Central

Antimicrobial prophylaxis is commonly used by clinicians for the prevention of numerous infectious diseases, including herpes simplex infection, rheumatic fever, recurrent cellulitis, meningococcal disease, recurrent uncomplicated urinary tract infections in women, spontaneous bacterial peritonitis in patients with cirrhosis, influenza, infective endocarditis, pertussis, and acute necrotizing pancreatitis, as well as infections associated with open fractures, recent prosthetic joint placement, and bite wounds. Perioperative antimicrobial prophylaxis is recommended for various surgical procedures to prevent surgical site infections. Optimal antimicrobial agents for prophylaxis should be bactericidal, nontoxic, inexpensive, and active against the typical pathogens that can cause surgical site infection postoperatively. To maximize its effectiveness, intravenous perioperative prophylaxis should be administered within 30 to 60 minutes before the surgical incision. Antimicrobial prophylaxis should be of short duration to decrease toxicity and antimicrobial resistance and to reduce cost. PMID:21719623

Enzler, Mark J.; Berbari, Elie; Osmon, Douglas R.

2011-01-01

262

Plant-derived antimicrobials reduce Listeria monocytogenes virulence factors in vitro, and down-regulate expression of virulence genes.  

PubMed

Listeria monocytogenes (LM) is a major foodborne pathogen causing septicemia, meningitis and death in humans. LM infection is preceded by its attachment to and invasion of human intestinal epithelium followed by systemic spread. The major virulence factors in LM include motility, hemolysin and lecithinase production. Reducing LM attachment to and invasion of host tissue and production of virulence factors could potentially control listeriosis in humans. This study investigated the efficacy of sub-inhibitory concentrations (SICs, concentrations not inhibiting bacterial growth) of three, generally regarded as safe (GRAS)-status, plant-derived antimicrobial compounds in reducing LM attachment to and invasion of human colon adenocarcinoma (Caco-2) and human brain microvascular endothelial cells (HBMEC). Additionally, the effect of these compounds on the aforementioned LM virulence factors was studied. The compounds and their respective SICs used relative to their MICs were trans-cinnamaldehyde (TC 0.50mM, 0.75mM with the MIC of 0.90mM), carvacrol (CR 0.50mM, 0.65mM with the MIC of 0.75mM), and thymol (TY 0.33mM, 0.50mM with the MIC of 0.60mM). All three-plant antimicrobials reduced LM adhesion to and invasion of Caco-2 and HBMEC (p<0.05). The compounds also decreased LM motility, hemolysin production and lecithinase activity (p<0.05). Real-time PCR data revealed that TC, CR, and TY down-regulated the expression of LM virulence genes by >3.0 folds compared to controls (p<0.05). Results suggest that TC, CR, and TY could potentially be used to control LM infection; however, in vivo studies are necessary to validate these results. PMID:22608657

Upadhyay, Abhinav; Johny, Anup Kollanoor; Amalaradjou, Mary Anne Roshni; Ananda Baskaran, Sangeetha; Kim, Kwang Sik; Venkitanarayanan, Kumar

2012-06-15

263

RP-HPLC analysis of the phenolic compounds of plant extracts. investigation of their antioxidant capacity and antimicrobial activity.  

PubMed

Extracts of aromatic plants of Greek origin were examined as potential sources of phenolic compounds. RP-HPLC with UV detection was employed for the identification and quantification of the phenolic antioxidants, present in methanolic extracts. The most abundant phenolic acids were ferulic acid (1.1-280 mg/100 g of dry sample) and caffeic acid (1.2-60 mg/100 g of dry sample). (+)-Catechin and quercetin were the most abundant flavonoids. Apigenin and luteolin were detected in high amounts in Menta pulegium and Thymus vulgaris, respectively. The antioxidant capacity was determined, in dried ground plants and in their methanol extracts, with the Rancimat test using sunflower oil as substrate. Both pulverized plants and extracts showed antioxidant capacity. Total phenolic content in the extracts was determined spectrometrically according to the Folin-Ciocalteu assay and ranged from 1 to 21 mg of gallic acid/100 g of dry sample. Antimicrobial activity of the extracts against selected microbes was also conducted in this study. PMID:15713039

Proestos, C; Chorianopoulos, N; Nychas, G-J E; Komaitis, M

2005-02-23

264

Isolation, diversity, and antimicrobial activity of rare actinobacteria from medicinal plants of tropical rain forests in Xishuangbanna, China.  

PubMed

Endophytic actinobacteria are relatively unexplored as potential sources of novel species and novel natural products for medical and commercial exploitation. Xishuangbanna is recognized throughout the world for its diverse flora, especially the rain forest plants, many of which have indigenous pharmaceutical histories. However, little is known about the endophytic actinobacteria of this tropical area. In this work, we studied the diversity of actinobacteria isolated from medicinal plants collected from tropical rain forests in Xishuangbanna. By the use of different selective isolation media and methods, a total of 2,174 actinobacteria were isolated. Forty-six isolates were selected on the basis of their morphologies on different media and were further characterized by 16S rRNA gene sequencing. The results showed an unexpected level of diversity, with 32 different genera. To our knowledge, this is the first report describing the isolation of Saccharopolyspora, Dietzia, Blastococcus, Dactylosporangium, Promicromonospora, Oerskovia, Actinocorallia, and Jiangella species from endophytic environments. At least 19 isolates are considered novel taxa by our current research. In addition, all 46 isolates were tested for antimicrobial activity and were screened for the presence of genes encoding polyketide synthetases and nonribosomal peptide synthetases. The results confirm that the medicinal plants of Xishuangbanna represent an extremely rich reservoir for the isolation of a significant diversity of actinobacteria, including novel species, that are potential sources for the discovery of biologically active compounds. PMID:19648362

Qin, Sheng; Li, Jie; Chen, Hua-Hong; Zhao, Guo-Zhen; Zhu, Wen-Yong; Jiang, Cheng-Lin; Xu, Li-Hua; Li, Wen-Jun

2009-10-01

265

Potential New Pharmacological Agents Derived From Medicinal Plants for the Treatment of Pancreatic Cancer.  

PubMed

In the present article, we reviewed plants and phytochemical compounds demonstrating beneficial effects in pancreatic cancer to find new sources of pharmaceutical agents. For this purpose, Scopus, PubMed, Web of Science, and Google scholar were searched for plants or herbal components with beneficial effects in the treatment of pancreatic cancer. Data were collected up to January 2013. The search terms were "plant," "herb," "herbal therapy," or "phytotherapy" and "pancreatic cancer" or "pancreas." All of the human in vivo and in vitro studies were included. According to studies, among diverse plants and phytochemicals, 12 compounds including apigenin, genistein, quercetin, resveratrol, epigallocatechin gallate, benzyl isothiocyanate, sulforaphane, curcumin, thymoquinone, dihydroartemisinin, cucurbitacin B, and perillyl alcohol have beneficial action against pancreatic cancer cells through 4 or more mechanisms. Applying their plausible synergistic effects can be an imperative approach for finding new efficient pharmacological agents in the treatment of pancreatic cancer. PMID:25493374

Azimi, Haniye; Khakshur, Ali Asghar; Abdollahi, Mohammad; Rahimi, Roja

2015-01-01

266

Improvement of water treatment pilot plant with Moringa oleifera extract as flocculant agent  

Microsoft Academic Search

Moringa oleifera extract is a high?capacity flocculant agent for turbidity removal in surface water treatment. A complete study of a pilot?plant installation has been carried out. Because of flocculent sedimentability of treated water, a residual turbidity occured in the pilot plant (around 30 NTU), which could not be reduced just by a coagulation?flocculation?sedimentation process. Because of this limitation, the pilot

2009-01-01

267

Quinones derived from plant secondary metabolites as anti-cancer agents.  

PubMed

Quinones are plant-derived secondary metabolites that present some anti-proliferation and anti-metastasis effects in various cancer types both in vitro and in vivo. This review focuses on the anti-cancer prospects of plant-derived quinones, namely, aloe-emodin, juglone, ?-lapachol, plumbagin, shikonin, and thymoquinone. We intend to summarize their anti-cancer effects and investigate the mechanism of actions to promote the research and development of anti-cancer agents from quinones. PMID:22931417

Lu, Jin-Jian; Bao, Jiao-Lin; Wu, Guo-Sheng; Xu, Wen-Shan; Huang, Ming-Qing; Chen, Xiu-Ping; Wang, Yi-Tao

2013-03-01

268

Antimicrobial peptide inhibition of fungalysin proteases that target plant type 19 Family IV defense chitinases  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cereal crops and other plants produce secreted seed chitinases that reduce pathogenic infection, most likely by targeting the fungal chitinous cell wall. We have shown that corn (Zea mays) produces three GH family 19, plant class IV chitinases, that help in protecting the plant against Fusarium and ...

269

Silver Nanoparticles in SiO2 Microspheres - Preparation by Spray Drying and Use as Antimicrobial Agent.  

PubMed

Silver nanoparticles embedded in SiO2 particles of micrometer size are prepared using spray drying. The spray drying is performed with a SiO2 sol (solvent water:ethanol 4: 1) containing SiO2 and silver particles of nanometer size. During spray drying the SiO2 nanoparticles aggregate to SiO2 microspheres whereas the silver particles exhibit only a small tendency of aggregation and keep their nanometer size. However under special conditions also the formation of crystalline silver rods is observed. The antibacterial activity of the resulting Ag/SiO2 powders is determined against the bacteria Escherichia coli and Bacillus subtilis. Because of this antibacterial acitivity and the fact that the powder of SiO2 microspheres exhibits a good dispersibility, such materials have an immense potential to be used as antimicrobial additive in processes like master batch or fiber production. PMID:24061743

Mahltig, Boris; Haufe, Helfried; Muschter, Kerstin; Fischer, Anja; Kim, Young Hwan; Gutmann, Emanuel; Reibold, Marianne; Meyer, Dirk Carl; Textor, Torsten; Kim, Chang Woo; Kang, Young Soo

2010-06-01

270

[Effects of plant polysaccharide compound agents on the photosynthetic characteristics and dry matter of soybean].  

PubMed

A field experiment was conducted to study the effects of foliar spraying three compound agents [plant polysaccharides (P1), plant polysaccharides and 5-aminolevulinic acid (P2), and plant polysaccharides and 5-aminolevulinic acid and dimethylpiperidinium chloride (P3)] at the initial flowering stage of soybean on its leaf chlorophyll content, photosynthesis and transpiration, dry matter accumulation and allocation, and grain yield. Within 35 days after spraying the three compound agents, the leaf chlorophyll content had obvious increase, and its decreasing trend with plant growth had somewhat delay. Compared with the control, spraying P1 and P3 increased the leaf photosynthetic rate and water use efficiency by more than 13.2% and 10.3%, respectively. With the spraying of the three compound agents, the dry matter accumulation in aerial part increased, and the allocation of dry matter from leaf to pod was also enhanced, with the contribution of post-anthesis assimilates to grain yield increased by more than 17.1%. The 100-grain mass and the pods and seeds per plant increased significantly after spraying P1 and P3, but had no significant increase after spraying P2. The grain yield of soybean treated with the three compound agents increased by more than 5.9%, compared with the control. This study showed that the three plant polysaccharide compound agents could increase the leaf chlorophyll content, delay the leaf-senescence, improve the leaf photosynthetic capacity and water status, effectively control the dry matter accumulation and post-anthesis assimilates allocation, and increase the grain yield of soybean. PMID:23173460

Bai, Wen-Bo; Song, Ji-Qing; Guo, Jin-Yi; Liu, Xing-Hai; Li, Ji-Hui

2012-07-01

271

Lipooligosaccharide Structure is an Important Determinant in the Resistance of Neisseria Gonorrhoeae to Antimicrobial Agents of Innate Host Defense  

PubMed Central

The strict human pathogen Neisseria gonorrhoeae has caused the sexually transmitted infection termed gonorrhea for thousands of years. Over the millennia, the gonococcus has likely evolved mechanisms to evade host defense systems that operate on the genital mucosal surfaces in both males and females. Past research has shown that the presence or modification of certain cell envelope structures can significantly impact levels of gonococcal susceptibility to host-derived antimicrobial compounds that bathe genital mucosal surfaces and participate in innate host defense against invading pathogens. In order to facilitate the identification of gonococcal genes that are important in determining levels of bacterial susceptibility to mediators of innate host defense, we used the Himar I mariner in vitro mutagenesis system to construct a transposon insertion library in strain F62. As proof of principle that this strategy would be suitable for this purpose, we screened the library for mutants expressing decreased susceptibility to the bacteriolytic action of normal human serum (NHS). We found that a transposon insertion in the lgtD gene, which encodes an N-acetylgalactosamine transferase involved in the extension of the ?-chain of lipooligosaccharide (LOS), could confer decreased susceptibility of strain F62 to complement-mediated killing by NHS. By complementation and chemical analyses, we demonstrated both linkage of the transposon insertion to the NHS-resistance phenotype and chemical changes in LOS structure that resulted from loss of LgtD production. Further truncation of the LOS ?-chain or loss of phosphoethanolamine (PEA) from the lipid A region of LOS also impacted levels of NHS-resistance. PEA decoration of lipid A also increased gonococcal resistance to the model cationic antimicrobial polymyxin B. Taken together, we conclude that the Himar I mariner in vitro mutagenesis procedure can facilitate studies on structures involved in gonococcal pathogenesis. PMID:21747781

Balthazar, Jacqueline T.; Gusa, Asiya; Martin, Larry E.; Choudhury, Biswa; Carlson, Russell; Shafer, William M.

2011-01-01

272

[Measurement of chemical agents in metallurgy field: electric steel plant].  

PubMed

The steel industry maintains its important position in the context of the Italian production involving thousands of workers. The iron and steel processes are divided into primary steel industry, production of intermediate minerals, and secondary steel, scrap from the production of semi-finished industrial and consumer sector (metal inserted into components and metal used for dissipative uses, primarily coatings) and industrial waste. The paper presents the results of environmental monitoring carried out in some electric steel plant for the measurement of airborne chemicals that characterize the occupational exposure of workers employed in particular area like electric oven, to treatment outside the furnace, continuous casting area. For the sampling of the pollutants were used both personal and in fixed positions samplers. The pollutants measured are those typical of steel processes inhalable dust, metals, respirable dust, crystalline silica, but also Polycyclic Aromatic Hydrocarbons (PAH), polychlorinated dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). PMID:23213795

Cottica, D; Grignani, E; Ghitti, R; Festa, D; Apostoli, P

2012-01-01

273

Inhibition of Fungal and Bacterial Plant Pathogens In Vitro and In Planta with Ultrashort Cationic Lipopeptides  

Microsoft Academic Search

Plant diseases constitute an emerging threat to global food security. Many of the currently available antimicrobial agents for agriculture are highly toxic and nonbiodegradable and cause extended environ- mental pollution. Moreover, an increasing number of phytopathogens develop resistance to them. Re- cently, we have reported on a new family of ultrashort antimicrobial lipopeptides which are composed of only four amino

Arik Makovitzki; Ada Viterbo; Yariv Brotman; Ilan Chet; Yechiel Shai

2007-01-01

274

Ecological niche modelling of an invasive alien plant and its potential biological control agents  

Microsoft Academic Search

Invasive alien plants are of concern in South Africa. Pompom weed (Campuloclinium macrocephalum) is currently invading the Grassland and Savannah biomes of South Africa and is likely to continue spreading in the southern African sub- region. Two possible biological control agents (Liothrips tractabilis and Cochylis campuloclinium) have been identified for control of pompom weed. We used ecological niche modelling to

P. D. Trethowan; M. P. Robertson; A. J. McConnachie

2011-01-01

275

Glyphosate as a selective agent for the production of fertile transgenic maize ( Zea mays L.) plants  

Microsoft Academic Search

Efficient and reproducible selection of transgenic cells is an essential component of a good transformation system. In this paper, we describe the development of glyphosate as a selective agent for the recovery of transgenic embryogenic corn callus and the production of plants tolerant to Roundup® herbicide. Glyphosate, the active ingredient in Roundup® herbicide inhibits the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) and

Arlene R. Howe; Charles S. Gasser; Sherri M. Brown; Stephen R. Padgette; Jesse Hart; Gregory B. Parker; Michael E. Fromm; Charles L. Armstrong

2002-01-01

276

Volatile analysis and antimicrobial screening of the parasitic plant Cuscuta reflexa Roxb. from Nepal.  

PubMed

The essential oil from the parasitic vine Cuscuta reflexa Roxb., collected from Kirtipur, Kathmandu, Nepal, was obtained by hydrodistillation and analysed by gas chromatography-mass spectrometry. From a total of 62 peaks, 61 compounds were identified in the oil, accounting for 99.6% of the oil. The majority of the essential oil was dominated by the relatively rare component cis-3-butyl-4-vinylcyclopentane (26.4%). The oil also contained substantial amounts of limonene (5.1%) and (E)-nerolidol (9.5%). Biological screening for antimicrobial activities did not show appreciable activity against either Gram-positive (Bacillus cereus and Staphylococcus aureus) or Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. However, marginal activity against Aspergillus niger was observed (minimum inhibitory concentration = 313 ?g/mL). PMID:24116676

Paudel, Prajwal; Satyal, Prabodh; Maharjan, Samjhana; Shrestha, Nawal; Setzer, William N

2014-01-01

277

Plant-based hydrocarbon esters from Tragia involucrata possess antimicrobial and anti-inflammatory activities.  

PubMed

Antimicrobial and anti-inflammatory activities of hydrocarbon esters obtained from Tragia involucrata were evaluated by disk-diffusion (250 µg/ml), and broth-dilution (500-7.8 µg/ml), methods against bacteria. Among the compounds, shellsol showed the most potent activity against Burkholderia pseudomallei (KHW), Aeromonas hydrophila, Staphylococcus aureus, Bacillus subtilis, Streptococcus pyogenes, Klebsiella pneumoniae, Proteus mirabilis, and Streptococcus pneumoniae. Interestingly, vinyl hexylether was active against food-spoilage bacteria (Bacillus cereus and Proteus vulgaris), 2, 4-methyl hexane also exerted antimicrobial activity against K. pneumoniae, S. pyogenes, B. pseudomallei, Alcaligens viscolactis, and Pseudomonas aeruginosa. 2-methylnonane and 2, 6-dimethyl heptane showed only weak activity. For example, shellsol showed bacteriostatic effect (MIC of 7.8 µg/ml) against A. hydrophila, vinyl hexylether (MIC of 15.6 µg/ml) against P. mirabilis, and 2, 4-methyl hexane (MIC of 31.25 µg/ml) on B. pseudomallei. Cytotoxic effects of compounds were assayed in human skin and monkey kidney cells (62.5-2000 µg/ml) by an XTT assay. The vinyl hexylether, 2, 4-dimethyl hexane and shellsol did not show any toxicity up to 1000 µg/ml concentrations. The 2-methylnonane and 2, 6-dimethyl heptane induced morphological changes (e.g. cell disintegration and lysis) of both cell types at a 2000 µg/ml. The vinyl hexylether, 2, 4-dimethyl hexane and shellsol were devoid of toxic effects; however, 2-methylnonane induced weight loss and severe necrosis as evidenced by histopathological and serum biochemical analysis in rats. Interestingly, shellsol showed the maximum inhibition of carrageenan-induced, paw oedema in rats. In conclusion, findings of this study clearly indicate that biologically active hydrocarbon esters, such as shellsol, vinyl hexylether, and 2, 4-dimethyl hexane isolated from T. involucrata, may effectively control the growth of certain food-borne and food-spoilage pathogens. PMID:23713670

Samy, Ramar Perumal; Sethi, Gautam; Chow, Vincent T K; Stiles, Bradley G

2013-04-01

278

Biochemical analysis of a multifunctional cytochrome P450 (CYP51) enzyme required for synthesis of antimicrobial triterpenes in plants  

PubMed Central

Members of the cytochromes P450 superfamily (P450s) catalyze a huge variety of oxidation reactions in microbes and higher organisms. Most P450 families are highly divergent, but in contrast the cytochrome P450 14?-sterol demethylase (CYP51) family is one of the most ancient and conserved, catalyzing sterol 14?-demethylase reactions required for essential sterol synthesis across the fungal, animal, and plant kingdoms. Oats (Avena spp.) produce antimicrobial compounds, avenacins, that provide protection against disease. Avenacins are synthesized from the simple triterpene, ?-amyrin. Previously we identified a gene encoding a member of the CYP51 family of cytochromes P450, AsCyp51H10 (also known as Saponin-deficient 2, Sad2), that is required for avenacin synthesis in a forward screen for avenacin-deficient oat mutants. sad2 mutants accumulate ?-amyrin, suggesting that they are blocked early in the pathway. Here, using a transient plant expression system, we show that AsCYP51H10 is a multifunctional P450 capable of modifying both the C and D rings of the pentacyclic triterpene scaffold to give 12,13?-epoxy-3?,16?-dihydroxy-oleanane (12,13?-epoxy-16?-hydroxy-?-amyrin). Molecular modeling and docking experiments indicate that C16 hydroxylation is likely to precede C12,13 epoxidation. Our computational modeling, in combination with analysis of a suite of sad2 mutants, provides insights into the unusual catalytic behavior of AsCYP51H10 and its active site mutants. Fungal bioassays show that the C12,13 epoxy group is an important determinant of antifungal activity. Accordingly, the oat AsCYP51H10 enzyme has been recruited from primary metabolism and has acquired a different function compared to other characterized members of the plant CYP51 family—as a multifunctional stereo- and regio-specific hydroxylase in plant specialized metabolism. PMID:23940321

Geisler, Katrin; Hughes, Richard K.; Sainsbury, Frank; Lomonossoff, George P.; Rejzek, Martin; Fairhurst, Shirley; Olsen, Carl-Erik; Motawia, Mohammed Saddik; Melton, Rachel E.; Hemmings, Andrew M.; Bak, Søren; Osbourn, Anne

2013-01-01

279

Uses of antimicrobial genes from microbial genome  

DOEpatents

We describe a method for mining microbial genomes to discover antimicrobial genes and proteins having broad spectrum of activity. Also described are antimicrobial genes and their expression products from various microbial genomes that were found using this method. The products of such genes can be used as antimicrobial agents or as tools for molecular biology.

Sorek, Rotem; Rubin, Edward M.

2013-08-20

280

Antimicrobial Activity of Plants Used in the Prevention and Control of Bovine Mastitis in Southern Brazil  

Microsoft Academic Search

SUMMARY. Based on informal interview, ethnoveterinary information about plants used in the preven- tion and control of bovine mastitis in Southern Brazil were obtained. Alternanthera brasiliana (L.) Ktze. (\\

César AVANCINI; José M. WIEST; Rodrigo DALL' AGNOL

281

Antimicrobial effect of zinc pyrithione  

Microsoft Academic Search

Synopsis The antimicrobial effect of zinc pyrithione has been studied with healthy scalps in relation to its ANTIDANDRUFF effect. Use of zinc pyrithione-containing shampoo sharply reduced the CORNEOCYTE COUNTS, while the similarly active antimicrobial agent, Irgasan DP-300 © had no effect on the corneocyte counts. Quantitative estimation of scalp microorganisms revealed that corresponding to the decrease in dandruff, Pityrospbrum ovale

GENJI IMOKAWA; HARUO SHIMIZU

282

Antimicrobial peptides: General overview and clinical implications in human health and disease  

Microsoft Academic Search

Antimicrobial peptides (AMPs) are evolutionarily conserved molecules involved in the defense mechanisms of a wide range of organisms. Produced in bacteria, insects, plants and vertebrates, AMPs protect against a broad array of infectious agents. In mammals these peptides protect against bacteria, viruses, fungi, and certain parasites. Recently, novel biologic effects of AMPs have been documented such as endotoxin neutralization, chemotactic

Eduardo Guaní-Guerra; Teresa Santos-Mendoza; Saúl O. Lugo-Reyes; Luis M. Terán

2010-01-01

283

Evaluation of linalool, a natural antimicrobial and insecticidal essential oil from basil: Effects on poultry  

Technology Transfer Automated Retrieval System (TEKTRAN)

Linalool is a natural plant product used in perfumes, cosmetics, and flavoring agents. Linalool has proven antimicrobial and insect repellant properties which indicate it might be useful for control of enteropathogens or insect pests in poultry production. However, there are no published reports t...

284

Natural Antioxidant Constituents from Selected Aromatic Plants and Their Antimicrobial Activity Against Selected Pathogenic Microorganisms  

Microsoft Academic Search

Summary Aromatic plants contain natural antioxidant constituents such as phenolic compounds, which have attracted a great deal of public and scientific interest because of their health- -promoting effects as antioxidants. Five plants, Filipendula ulmaria (meadow sweet), Cratae- gus monogyna (hawthorn), Polygonum aviculare (polygonum), Potentilla anserina (silverweed), and Pelargonium purpureum (little robin), have been examined in order to determine their phenolic

Charalampos Proestos; Ioannis Spyridon Boziaris; Maria Kapsokefalou; Michael Komaitis

2008-01-01

285

Screening of medicinal plants from Trinidad and Tobago for antimicrobial and insecticidal properties  

Microsoft Academic Search

Antibacterial activity in 51 extracts from 29 plant species currently used in traditional medicine in Trinidad and the neighbouring Caribbean islands was tested for by the agar dilution streak method using six bacteria: Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis. The extracts from eight of the plants tested showed significant activity against one or

C. M Chariandy; C. E Seaforth; R. H Phelps; G. V Pollard; B. P. S Khambay

1999-01-01

286

Synthesis of 6-fluoro-1,4-dihydro-4-oxo-quinoline-3-carboxylic acid derivatives as potential antimicrobial agents.  

PubMed

In the present study, a series of 1-ethyl/benzyl-6-fluoro-7-(substituted piperazin-1-yl)1,4-dihydro-4-oxo-quinoline-3-carboxylic acid were synthesized and characterized by IR, 1H-NMR, mass spectral and elemental analysis. The in vitro antibacterial and antifungal activities of the compounds were evaluated by paper disc diffusion method. The minimum inhibitory concentrations (MIC) of the compounds were also determined by agar streak dilution method. The in vivo antibacterial activity of the compounds against Escherichia coli was also evaluated by mouse protection test. All the compounds exhibited significant antibacterial and weak antifungal activities. The in vivo antibacterial activity (ED50) against E. coli was 50-160 mg kg(-1) in the order of 7<9<8<10. 1-ethyl-6-fluoro-7-(2,5-dioxo-piperazin-1-yl)1,4-dihydro-4-oxo-quinoline-3-carboxylic acid (7) was found to exhibit the most potent in vitro antimicrobial activity with MIC of 4.1, 3.1, 3.1, 2.4, 1, 1, 25 and >100 microg mL(-1) against Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus, Bacillus cereus, E. coli, Klebsiella pneumoniae, Candida albicans and Aspergillus niger. PMID:14642332

Rameshkumar, Natesh; Ashokkumar, Mohan; Subramanian, Ekambaram Harihara; Ilavarasan, Raju; Sridhar, Seshaiah Krishnan

2003-01-01

287

In vitro susceptibilities of caprine Mycoplasma agalactiae field isolates to six antimicrobial agents using the E test methodology.  

PubMed

The minimum inhibitory concentrations (MICs) of enrofloxacin, ciprofloxacin, spectinomycin, tetracycline, spiramycin and erythromycin against 30 caprine Greek isolates of Mycoplasma agalactiae were determined using E test methodology. The E test strips were placed on Eaton's agar medium without antimicrobials and phenol red. MICs were then read by determining where the growth inhibition zone intersected with the MIC scale on the strip. An MIC value of 8?µg/mL was considered as a guide to mycoplasma resistance. All isolates were sensitive to fluoroquinolones (MIC50, 0.19?g/mL; MIC90, 0.38?µg/mL; highest MIC, 0.5?µg/mL), spectinomycin (MIC50, 0.5?µg/mL; MIC90, 1?µg/mL; highest MIC, 1?µg/mL), and spiramycin (MIC50, 1?µg/mL; MIC90, 1.5?µg/mL; highest MIC, 2?µg/mL). Two strains exhibited resistance to tetracycline (MIC 32?µg/mL) but these were not found to carry any of the tet(M), tet(O), and tet(S) resistance genes. Finally all isolates expressed resistance to erythromycin (MIC50, 128?µg/mL; MIC90, >256?µg/mL). PMID:25439442

Filioussis, George; Petridou, Evanthia; Giadinis, Nektarios D; Kritas, Spyridon K

2014-12-01

288

Editorial of the Special Issue Antimicrobial Polymers  

PubMed Central

The special issue “Antimicrobial Polymers” includes research and review papers concerning the recent advances on preparation of antimicrobial polymers and their relevance to industrial settings and biomedical field. Antimicrobial polymers have recently emerged as promising candidates to fight microbial contamination onto surfaces thanks to their interesting properties. In this special issue, the main strategies pursued for developing antimicrobial polymers, including polymer impregnation with antimicrobial agents or synthesis of polymers bearing antimicrobial moieties, were discussed. The future application of these polymers either in industrial or healthcare settings could result in an extremely positive impact not only at the economic level but also for the improvement of quality of life. PMID:24005863

Piozzi, Antonella; Francolini, Iolanda

2013-01-01

289

Screening and Scoring of Antimicrobial and Biological Activities of Italian Vulnerary Plants against Major Oral Pathogenic Bacteria  

PubMed Central

This study aims to evaluate the activity of Italian vulnerary plants against the most important oral pathogenic bacteria. This estimate was accomplished through a fivefold process: (a) a review of ethnobotanical and microbiological data concerning the Italian vulnerary plants; (b) the development of a scoring system to rank the plants; (c) the comparative assessment of microbiological properties; (d) the assessment of potential cytotoxic effects on keratinocyte-like cells and gingival fibroblasts in culture by XTT cell viability assay; (e) clinical evaluation of the most suitable plant extract as antibacterial agent in a home-made mouthwash. The study assays hexane (H), ethanol (E), and water (W) extracts from 72 plants. The agar diffusion method was used to evaluate the activity against Streptococcus mutans, Streptococcus sobrinus, Lactobacillus casei, and Actinomyces viscosus. Twenty-two plants showed appreciable activity. The extracts showing the strongest antibacterial power were those from Cotinus coggygria Scop., Equisetum hyemale L., Helichrysum litoreum Guss, Juniperus communis L., and Phyllitis scolopendrium (L.) Newman subsp. scolopendrium. The potential cytotoxic effect of these extracts was assessed. On the basis of these observations, a mouth-rinse containing the ethanolic extract of H. litoreum has been tested in vivo, resulting in reduction of the salivary concentration of S. mutans. PMID:24302963

Ferrazzano, Gianmaria F.; Roberto, Lia; Catania, Maria Rosaria; Chiaviello, Angela; De Natale, Antonino; Roscetto, Emanuela; Pinto, Gabriele; Pollio, Antonino; Ingenito, Aniello; Palumbo, Giuseppe

2013-01-01

290

Comparative in vitro activities of the investigational fluoroquinolone DC-159a and other antimicrobial agents against human mycoplasmas and ureaplasmas.  

PubMed

The in vitro susceptibilities of 151 unique clinical isolates of Mycoplasma pneumoniae, Mycoplasma hominis, Mycoplasma fermentans, Mycoplasma genitalium, and Ureaplasma species to DC-159a, an investigational fluoroquinolone, in comparison with those to other agents were determined. Macrolides were the most active agents against M. pneumoniae and M. genitalium, whereas clindamycin was most active against M. hominis. DC-159a MICs were or=99.9% of the inoculum at 24 h for 2 isolates. The excellent in vitro activity of DC-159a demonstrates its potential for use in the treatment of infections due to mycoplasmas and ureaplasmas. PMID:18663020

Waites, Ken B; Crabb, Donna M; Duffy, Lynn B

2008-10-01

291

Prevention of ventilator-associated pneumonia, mortality and all intensive care unit acquired infections by topically applied antimicrobial or antiseptic agents: a meta-analysis of randomized controlled trials in intensive care units  

Microsoft Academic Search

Introduction  Given the high morbidity and mortality attributable to ventilator-associated pneumonia (VAP) in intensive care unit (ICU)\\u000a patients, prevention plays a key role in the management of patients undergoing mechanical ventilation. One of the candidate\\u000a preventive interventions is the selective decontamination of the digestive or respiratory tract (SDRD) by topical antiseptic\\u000a or antimicrobial agents. We performed a meta-analysis to investigate the

Claudia Pileggi; Aida Bianco; Domenico Flotta; Carmelo GA Nobile; Maria Pavia

2011-01-01

292

Expression of an engineered heterologous antimicrobial peptide in potato alters plant development and mitigates normal abiotic and biotic responses.  

PubMed

Antimicrobial cationic peptides (AMPs) are ubiquitous small proteins used by living cells to defend against a wide spectrum of pathogens. Their amphipathic property helps their interaction with negatively charged cellular membrane of the pathogen causing cell lysis and death. AMPs also modulate signaling pathway(s) and cellular processes in animal models; however, little is known of cellular processes other than the pathogen-lysis phenomenon modulated by AMPs in plants. An engineered heterologous AMP, msrA3, expressed in potato was previously shown to cause resistance of the transgenic plants against selected fungal and bacterial pathogens. These lines together with the wild type were studied for growth habits, and for inducible defense responses during challenge with biotic (necrotroph Fusarium solani) and abiotic stressors (dark-induced senescence, wounding and temperature stress). msrA3-expression not only conferred protection against F. solani but also delayed development of floral buds and prolonged vegetative phase. Analysis of select gene transcript profiles showed that the transgenic potato plants were suppressed in the hypersensitive (HR) and reactive oxygen species (ROS) responses to both biotic and abiotic stressors. Also, the transgenic leaves accumulated lesser amounts of the defense hormone jasmonic acid upon wounding with only a slight change in salicylic acid as compared to the wild type. Thus, normal host defense responses to the pathogen and abiotic stressors were mitigated by msrA3 expression suggesting MSRA3 regulates a common step(s) of these response pathways. The stemming of the pathogen growth and mitigating stress response pathways likely contributes to resource reallocation for higher tuber yield. PMID:24147012

Goyal, Ravinder K; Hancock, Robert E W; Mattoo, Autar K; Misra, Santosh

2013-01-01

293

Plant growth-promoting rhizobacteria (PGPR): Their potential as antagonists and biocontrol agents  

PubMed Central

Bacteria that colonize plant roots and promote plant growth are referred to as plant growth-promoting rhizobacteria (PGPR). PGPR are highly diverse and in this review we focus on rhizobacteria as biocontrol agents. Their effects can occur via local antagonism to soil-borne pathogens or by induction of systemic resistance against pathogens throughout the entire plant. Several substances produced by antagonistic rhizobacteria have been related to pathogen control and indirect promotion of growth in many plants, such as siderophores and antibiotics. Induced systemic resistance (ISR) in plants resembles pathogen-induced systemic acquired resistance (SAR) under conditions where the inducing bacteria and the challenging pathogen remain spatially separated. Both types of induced resistance render uninfected plant parts more resistant to pathogens in several plant species. Rhizobacteria induce resistance through the salicylic acid-dependent SAR pathway, or require jasmonic acid and ethylene perception from the plant for ISR. Rhizobacteria belonging to the genera Pseudomonas and Bacillus are well known for their antagonistic effects and their ability to trigger ISR. Resistance-inducing and antagonistic rhizobacteria might be useful in formulating new inoculants with combinations of different mechanisms of action, leading to a more efficient use for biocontrol strategies to improve cropping systems. PMID:23411488

Beneduzi, Anelise; Ambrosini, Adriana; Passaglia, Luciane M.P.

2012-01-01

294

Identification of natural antimicrobial agents to treat dengue infection: In vitro analysis of latarcin peptide activity against dengue virus  

PubMed Central

Background Although there have been considerable advances in the study of dengue virus, no vaccines or anti-dengue drugs are currently available for humans. Therefore, new approaches are necessary for the development of potent anti-dengue drugs. Natural antimicrobial peptides (AMPs) with potent antiviral activities are potential hits-to-leads for antiviral drug discovery. We performed this study to identify and characterise the inhibitory potential of the latarcin peptide (Ltc 1, SMWSGMWRRKLKKLRNALKKKLKGE) against dengue virus replication in infected cells. Results The Ltc 1 peptide showed a significantly inhibitory effect against the dengue protease NS2B-NS3pro at 37°C, a physiological human temperature, (IC50, 12.68?±?3.2 ?M), and greater inhibitory effect was observed at 40°C, a temperature similar to a high fever (IC50, 6.58?±?4.1 ?M). A greater reduction in viral load (p.f.u./ml) was observed at simultaneous (0.7?±?0.3 vs. 7.2?±?0.5 control) and post-treatment (1.8?±?0.7 vs. 6.8?±?0.6 control) compared to the pre-treatment (4.5?±?0.6 vs. 6.9?±?0.5 control). Treatment with the Ltc 1 peptide reduced the viral RNA in a dose-dependent manner with EC50 values of 8.3?±?1.2, 7.6?±?2.7 and 6.8?±?2.5 ?M at 24, 48 and 72 h, respectively. Conclusions The Ltc 1 peptide exhibited significant inhibitory effects against dengue NS2B-NS3pro and virus replication in the infected cells. Therefore, further investigation is necessary to develop the Ltc 1 peptide as a new anti-dengue therapeutic. PMID:24885331

2014-01-01

295

Waging War Against Extended Spectrum Beta Lactamase and Metallobetalactamase Producing Pathogens- Novel Adjuvant Antimicrobial Agent Cse1034- An Extended Hope  

PubMed Central

Preamble: In the visage of multidrug resistance among gram negative bacilli, we look forward to carbapenem group of drugs as empiric choice in seriously ill patients. However increasing resistance to carbapenems, the last resort, is of growing concern for all. It’s high time to look beyond Carbapenems and emphasize on Carbapenem sparers. Objective: This study is to find the susceptibility pattern of the novel adjuvant antimicrobial CSE 1034 a combination of Ceftriaxone+sulbactam+disodium edetate for the current ESBL and MBL isolates in a tertiary care centre. Materials and Methods: A total of 823 gram negative bacterial isolates were obtained from different clinical specimens during the period of March, 2013 to October, 2013. The overall prevalence of metallobetalactamase producing gram negative organisms was 11 percent (n=91). We included a total of 141 clinical isolates for this study. Results: Among 141 clinical isolates, 50 isolates (35%) were ESBL producers and 91 (65%) were MBL producers. Maximum numbers of ESBL producers were identified in Escherichia coli followed by Klebsiella pneumoniae, Acinetobacter baumannii and Proteus spp. Maximum numbers of MBL producers were identified in Klebsiella pneumoniae followed by Pseudomonas aeruginosa. CSE 1034 (Ceftriaxone+sulbactam+disodium edetate) showed fairly good in-vitro susceptibility for these ESBL and MBL producing isolates. It exhibited 64 % to 100% susceptibility and 18% to 22% intermediate sensitivity to ESBL producing isolates and 42 % to 89 % susceptible and 10 % to 51 % intermediate response to MBL producing isolates. Conclusion: With increasing resistance to the commonly prescribed drugs used to treat infections caused by variety of gram negative organisms, Ceftriaxone+sulbactam+disodium edetate, a novel Antibiotic Adjuvant Entity (AAE) may be a promising option. PMID:25120981

Sanjith, S; Bhalekar, Pallavi; Keny, Dipti

2014-01-01

296

76 FR 4120 - The National Antimicrobial Resistance Monitoring System Strategic Plan 2011-2015; Request for...  

Federal Register 2010, 2011, 2012, 2013

...The National Antimicrobial Resistance Monitoring System (NARMS...susceptibility of enteric bacteria to antimicrobial agents of...systems monitoring antimicrobial resistance in other countries. Foodborne...States are infected with these bacteria, resulting in tens of...

2011-01-24

297

Leaves Antimicrobial Activity of Glycyrrhiza glabra L.  

PubMed

Licorice (Glycyrrhiza glabra L.) is an important medicinal plant. In this study, the antimicrobial activities of ethanolic and aqueous extracts from licorice leaves were studied compared to root extracts activities. Bacillus subtilis, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli, and Candida albicans were used as test organisms. Antimicrobial activity was tested by paper disc agar diffusion and serial dilution methods in order to determine minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The root and leave extracts showed activity against Candida albicans, and tested gram-positive bacteria in a dose dependent manner. The ethanolic extract of the leaves was the most active extract against gram-positive bacteria. Its effectiveness against strains provides hope that it can serve as an alternative therapeutic agent. PMID:24381608

Irani, Mahboubeh; Sarmadi, Marziyeh; Bernard, Françoise; Ebrahimi Pour, Gholam Hossein; Shaker Bazarnov, Hossein

2010-01-01

298

Terrestrial Plant-Derived Anticancer Agents and Plant Species Used in Anticancer Research  

Microsoft Academic Search

Cancer is a major cause of death and the number of new cases, as well as the number of individuals living with cancer, is expanding continuously. Due to the enormous propensity of plants that synthesize mixtures of structurally diverse bioactive compounds, the plant kingdom is potentially a very diverse source of chemical constituents with tumor cytotoxic activity. Despite the successful

Spiridon E. Kintzios

2006-01-01

299

Comparison of Essential Oils from Three Plants for Enhancement of Antimicrobial Activity of Nitrofurantoin against Enterobacteria  

Microsoft Academic Search

Background: Piperitone from plant essential oils enhancesbactericidal activities of nitrofurantoin and furazolidone against bacteria from the family Enterobacteriaceae. In this study, the essential oils of spearmint (Mentha spicata L.), dill (Anethum graveolens L.) and peppermint (Mentha piperita L.)were screened for augmentation of nitrofurantoin activity and the most active components were determined. Method: The effects of essential oils and their components

Fatemeh Rafii; Ahmad R. Shahverdi

2007-01-01

300

Comparative antimicrobial activity of tannin extracts from perennial plants on mastitis pathogens  

Technology Transfer Automated Retrieval System (TEKTRAN)

Three strains of pathogenic bacteria were treated with condensed tannins (CT) purified from eight different woody plant species to investigate their inhibition effect on the growth of these bacteria in vitro. Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus were tested against low...

301

Susceptibilities of 394 Bacteroides fragilis, non-B. fragilis group Bacteroides species, and Fusobacterium species to newer antimicrobial agents.  

PubMed Central

The susceptibilities of 374 selected beta-lactamase-producing gram-negative anaerobes (including 22 cefoxitin-resistant strains and 36 strains refractory to the enhancing effect of beta-lactamase inhibitors) and 20 beta-lactamase-negative strains were tested by agar dilution against selected new agents. The organisms included 217 Bacteroides fragilis group strains, 137 non-B. fragilis group Bacteroides spp., and 40 fusobacteria. All strains were susceptible to piperacillin-tazobactam, imipenem, and meropenem. For the B. fragilis group, 96% were susceptible to ampicillin-sulbactam, 95% were susceptible to amoxicillin-clavulanate and cefoperazone-sulbactam, 94% were susceptible to tosufloxacin, 91% were susceptible to cefoxitin, 88% were susceptible to trospectomycin, and 73% were susceptible to cefotetan. For the beta-lactamase-positive non-B. fragilis group Bacteroides spp., greater than or equal to 94% were susceptible to cefoxitin, amoxicillin-clavulanate, ampicillin-sulbactam, cefoperazone-sulbactam, and trospectomycin, 90% were susceptible to cefotetan, and 85% were susceptible to tosufloxacin (the most resistant strains were B. bivius and B. disiens). For the beta-lactamase-positive fusobacteria, greater than or equal to 97% were susceptible to amoxicillin-clavulanate, ampicillin-sulbactam, cefoperazone-sulbactam, trospectomycin, and cefoxitin, 90% were susceptible to cefotetan, and 89% were susceptible to tosufloxacin. All agents showed excellent activity against beta-lactamase-negative strains (for trospectomycin, 95% were susceptible; for all other drugs, 100% were susceptible). Overall, both carbapenems and piperacillin-tazobactam were most active. Amoxicillin-clavulanate, ampicillin-sulbactam, and cefoperazone-sulbactam lacked activity against some cefoxitin-resistant B. fragilis group strains but had excellent activity against other organisms. Tosufloxacin, a new quinolone, had very good activity against B. fragilis group strains (94% susceptible), good activity against other beta-lactamase-positive strains (less than or equal 85% susceptible), and excellent activity against beta-lactamase-negative strains (100% susceptible; MIC for 90% of strains, 0.5 microgram/ml). Trospectomycin was active against >90% of all strains except for B. fragilis group strains (88% susceptible; MIC for 90% of strains, 32 microgram/ml). Clinical studies are required to delineate the role of newer agents in the therapy of anaerobic infections. PMID:1929264

Appelbaum, P C; Spangler, S K; Jacobs, M R

1991-01-01

302

Antimicrobial activity of plant essential oils against Escherichia coli O157:H7 and Salmonella on lettuce.  

PubMed

Foodborne outbreaks associated with the consumption of fresh produce have increased. In an effort to identify natural antimicrobial agents as fresh produce-wash, the effect of essential oils in reducing enteric pathogens on iceberg and romaine lettuce was investigated. Lettuce pieces were inoculated with a five-strain cocktail of Escherichia coli O157:H7 or Salmonella enterica (5 log CFU/g) and then immersed in a treatment solution containing 5 ppm free chlorine, cinnamaldehyde, or Sporan(®) (800 and 1000 ppm) alone or in combination with 200 ppm acetic acid (20%) for 1 min. Treated leaves were spin-dried and stored at 4°C. Samples were taken to determine the surviving populations of E. coli O157:H7, Salmonella, total coliforms, mesophilic and psychrotrophic bacteria, and yeasts and molds during the 14-day storage period. The effect of treatments on lettuce color and texture was also determined. Cinnamaldehyde-Tween (800 ppm, 800T) reduced E. coli O157:H7 by 2.89 log CFU/g (p<0.05) on iceberg lettuce at day 0; Sporan(®)-acetic acid (1000SV) reduced E. coli O157:H7 and Salmonella on iceberg and romaine lettuce by 2.68 and 1.56 log CFU/g (p<0.05), respectively, at day 0. The effect of essential oils was comparable to that of 5 ppm free chlorine in reducing E. coli O157:H7 and Salmonella populations on iceberg and romaine lettuce throughout the storage time. The natural microbiota on treated lettuce leaves increased during the storage time, but remained similar (p>0.05) to those treated with chlorine and control (water). The texture and the color of iceberg and romaine lettuce treated with essential oils were not different from the control lettuce after 14 days of storage. This study demonstrates the potential of Sporan(®) and cinnamaldehyde as effective lettuce washes that do not affect lettuce color and texture. PMID:23256843

Yossa, Nadine; Patel, Jitendra; Millner, Patricia; Ravishankar, Sadhana; Lo, Y Martin

2013-01-01

303

Sweetening agents of plant origin: Phenylpropanoid constituents of seven sweet-tasting plants  

Microsoft Academic Search

Field inquiries and organoleptic tests for sweet taste led to the procurement of samples ofPiper marginatum (dried leaves),Tagetes filicifolia (fresh whole plants),Osmorhiza longistylis (fresh roots),Foeniculum vulgare (fresh aerial parts),Myrrhis odorata (fresh whole plants),Ocimum basilicum (fresh aerial parts), andIllicium verum (dried fruits). Follow-up laboratory studies of the leaves ofPiper marginatum demonstrated that trans-anethole (a phenylpropanoid) was the major sweet constituent of

R. A. Hussain; L. J. Poveda; J. M. Pezzuto; D. D. Soejarto; A. D. Kinghorn

1990-01-01

304

Evaluation of Antimicrobial Activity of the Methanol Extracts from 8 Traditional Medicinal Plants  

PubMed Central

The methanol extract of 12 medicinal plants were evaluated for its antibacterial activity against Gram-positive (5 strains) and Gram-negative bacteria (10 strains) by assay for minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) . The antibacterial activity was determined by an agar dilution method (according to the guidelines of Clinical and Laboratory Standard Institute) . All the compounds (12 extracts) of the 8 medicinal plants (leaf or root) were active against both Gram-negative and Gram-positive bacteria. Gram-negative showed a more potent action than Gram positive bacteria. The MIC concentrations were various ranged from 0.6 ?g/ml to 5000 ?g/ml. The lowest MIC (0.6 ?g/ml) and MBC (1.22 ?g/ml) values were obtained with extract on 4 and 3 of the 15 microorganisms tested, respectively. PMID:24278548

Kang, Chang-Geun; Hah, Dae-Sik; Kim, Chung-Hui; Kim, Young-Hwan; Kim, Euikyung

2011-01-01

305

Antimicrobial activity of the carnivorous plant Dionaea muscipula against food-related pathogenic and putrefactive bacteria.  

PubMed

Solvent extracts from the carnivorous plant Dionaea muscipula (Venus flytrap) were prepared using eight different organic solvents, and examined for antibacterial activity against food-related pathogenic and putrefactive bacteria. All solvent extracts showed higher antibacterial activity against gram positive bacteria than against gram negative bacteria. The TLC-bioautography analysis of the extracts revealed that a yellow spot was detected at Rf value of 0.85, which showed strong antibacterial activity. The UV, MS, and NMR analyses revealed that the antibacterial compound was plumbagin. PMID:24077538

Ogihara, Hirokazu; Endou, Fumiko; Furukawa, Soichi; Matsufuji, Hiroshi; Suzuki, Kouichi; Anzai, Hiroshi

2013-01-01

306

In Vitro Susceptibilities to and Bactericidal Activities of Garenoxacin (BMS-284756) and Other Antimicrobial Agents against Human Mycoplasmas and Ureaplasmas  

PubMed Central

The in vitro susceptibilities to garenoxacin (BMS-284756), an investigational des-fluoroquinolone, and eight other agents were determined for 63 Mycoplasma pneumoniae, 45 Mycoplasma hominis, 15 Mycoplasma fermentans, and 68 Ureaplasma sp. isolates. Garenoxacin was the most active quinolone, inhibiting all isolates at ?1 ?g/ml. The garenoxacin MIC at which 90% of isolates are inhibited (MIC90s; ?0.008 ?g/ml) was at least 4-fold less than those of moxifloxacin and clindamycin, 8-fold less than that of sparfloxacin, and 64-fold less than those of levofloxacin and ciprofloxacin for M. pneumoniae. For M. hominis, the garenoxacin MIC90 (?0.008 ?g/ml) was 4-fold less than those of clindamycin and moxifloxacin, 8-fold less than that of sparfloxacin, and 64-fold less than those of levofloxacin and ciprofloxacin. All 15 M. fermentans isolates were inhibited by garenoxacin at concentrations ?0.008 ?g/ml, making it the most active drug tested against this organism. For Ureaplasma spp., the garenoxacin MIC90 (0.25 ?g/ml) was equivalent to those of moxifloxacin and doxycycline, 4-fold less than those of levofloxacin and sparfloxacin, 8-fold less than that of azithromycin, and 32-fold less than that of ciprofloxacin. Garenoxacin and the other fluoroquinolones tested were demonstrated to have bactericidal activities against M. pneumoniae and M. hominis by measurement of minimal bactericidal activities and by time-kill studies. Further study of garenoxacin is required, as it has great potential for use in the treatment of infections due to mycoplasmas and ureaplasmas. PMID:12499185

Waites, Ken B.; Crabb, Donna M.; Bing, Xue; Duffy, Lynn B.

2003-01-01

307

Efficacy and safety of levofloxacin in patients with bacterial pneumonia evaluated according to the new "Clinical Evaluation Methods for New Antimicrobial Agents to Treat Respiratory Infections (Second Version)".  

PubMed

The guideline for the "Clinical Evaluation Methods for New Antimicrobial Agents to Treat Respiratory Infections (Second Version)," published by the Japanese Society of Chemotherapy in January 2012, was proposed to achieve consistency with FDA guidelines based on the concept of clinical evaluation used in Japan. We assessed the clinical efficacy of levofloxacin (LVFX) in patients with bacterial pneumonia according to this new set of guidelines for the first time. The clinical efficacy of LVFX in patients with community-acquired pneumonia (CAP) and healthcare-associated pneumonia (HCAP) at the test of cure (TOC) was 87.5% (56/64) and 85.7% (6/7), respectively, with an overall efficacy of 87.3% (62/71). The clinical efficacy of LVFX at TOC was as follows: intravenous 81.5% (22/27), oral 88.9% (24/27), switchover from intravenous to oral administration 100% (10/10), respectively. The bacterial eradication rate in the patients with CAP and HCAP and overall efficacy at the end of therapy (EOT) was 95.3% (41/43), 100.0% (4/4) and 95.7% (45/47), respectively. The frequent causative bacterial strains included Streptococcus pneumoniae (18), Haemophilus influenzae (14) and Moraxella catarrhalis (6). The incidence of adverse reactions in the patients whose safety was evaluated was 15.7% (14/89), similar to that previously reported. The clinical efficacy of LVFX at the early phase, EOT and TOC of CAP, as assessed according to the new and former guidelines, was 70.4% (38/54) and 27.8% (15/54), 87.0% (60/69) and 79.1% (53/67), 87.5% (56/64) and 88.1% (59/67), respectively, with no significant differences. Therefore, the new efficacy evaluation method can be used in exchange for the former evaluation method. PMID:24787737

Mukae, Hiroshi; Kawanami, Toshinori; Yatera, Kazuhiro; Yanagihara, Katsunori; Yamamoto, Yoshihiro; Kakeya, Hiroshi; Tokimatsu, Issei; Kadota, Junichi; Kohno, Shigeru

2014-07-01

308

The production of recombinant cationic ?-helical antimicrobial peptides in plant cells induces the formation of protein bodies derived from the endoplasmic reticulum.  

PubMed

Synthetic linear antimicrobial peptides with cationic ?-helical structures, such as BP100, are valuable as novel therapeutics and preservatives. However, they tend to be toxic when expressed at high levels as recombinant peptides in plants, and they can be difficult to detect and isolate from complex plant tissues because they are strongly cationic and display low extinction coefficient and extremely limited immunogenicity. We therefore expressed BP100 with a C-terminal tag which preserved its antimicrobial activity and demonstrated significant accumulation in plant cells. We used a fluorescent tag to trace BP100 following transiently expression in Nicotiana benthamiana leaves and showed that it accumulated in large vesicles derived from the endoplasmic reticulum (ER) along with typical ER luminal proteins. Interestingly, the formation of these vesicles was induced by BP100. Similar vesicles formed in stably transformed Arabidopsis thaliana seedlings, but the recombinant peptide was toxic to the host during latter developmental stages. This was avoided by selecting active BP100 derivatives based on their low haemolytic activity even though the selected peptides remained toxic to plant cells when applied exogenously at high doses. Using this strategy, we generated transgenic rice lines producing active BP100 derivatives with a yield of up to 0.5% total soluble protein. PMID:24102775

Company, Nuri; Nadal, Anna; La Paz, José-Luis; Martínez, Sílvia; Rasche, Stefan; Schillberg, Stefan; Montesinos, Emilio; Pla, Maria

2014-01-01

309

Investigation of medicinal plants of togo for antiviral and antimicrobial activities.  

PubMed

Methanol extracts were prepared from 19 medicinal plants of Togo and, by means of standard laboratory tests, were analysed for antiviral and antibiotic activities. Ten of the 19 showed significant antiviral activity and all but two displayed antibiotic activity. Extracts of three species, Adansonia digitata (the most potent), Conyza aegyptiaca and Palisota hirsuta , were active against all three test viruses (herpes simplex, Sindbis and poliovirus). The other seven, however, were more selective, showing activity against only one or two viruses. The antibiotic profiles varied considerably. The observation that each extract showed a distinctive permutation of target organisms suggests that different bioactive phytochemicals are present in each species. Only two of the extracts were devoid of bioactivity. PMID:21214438

Anani, K; Hudson, J B; de Souza, C; Akpagana, K; Tower, G H; Arnason, J T; Gbeassor, M

2000-01-01

310

Plant-bacteria bioremediation agents affect the response of plant bioindicators independent of 2-chlorobenzoic acid degradation  

SciTech Connect

Plants are known to degrade toxicants in soil and are potentially useful bioremediation agents. The authors developed plant-bacteria associations (e.g., Meadow brome [Bromus riparius] and Pseudomonas aeruginosa strain R75) that degrade 2-chlorobenzoic acid (2CBA) in soil, and assessed their success using Slender wheatgrass (Agropyron trachycaulum) germination as a bioindicator of 2CBA levels. Gas chromatography was used to chemically assess 2CBA levels. Specific plant-bacteria bioremediation treatments decreased soil 2CBA levels by 17 to 52%, but bioindicator response did not correspond to chemical analysis. Contaminated and uncontaminated soil was subjected to bioremediation treatments. After 42 days, uncontaminated soil was collected and amended to various 2CBA levels. This soil and the remediated soil were analyzed by the plant bioindicator and gas chromatography. Bioremediation treatments altered germination of Slender wheatgrass in both contaminated and noncontaminated soils to a similar extent. These treatments decreased the toxicity of 2CBA to Slender wheatgrass in both contaminated and noncontaminated soils to a similar extent. These treatments decreased the toxicity of 2CBA to Slender wheatgrass at low 2CBA levels, but increased the toxicity of 2CBA at high 2CBA levels. For example, germination in soil subjected to the Meadow brome and R75 treatment was increased by ca. 30% at 50 mg kg{sup {minus}1} 2CBA, but decreased by ca. 50% at 150 mg kg{sup {minus}1} 2CBA. The results indicate that specific plant-bacteria bioremediation treatments affect plant bioindicator response independent of 2CBA degradation, and may confound efforts to determine the toxicity of 2CBA in soil.

Siciliano, S.D.; Germida, J.J. [Univ. of Saskatchewan, Saskatoon, Saskatchewan (Canada)

1995-12-31

311

Medicinal plants used as antitumor agents in Brazil: an ethnobotanical approach.  

PubMed

WE DESCRIBE THE MEDICINAL PLANTS THAT HAVE BEEN REPORTED TO BE ANTITUMOR AGENTS AND THAT HAVE BEEN USED IN ETHNOBOTANIC RESEARCH IN BRAZIL TO ANSWER THE FOLLOWING QUESTIONS: what is the abundance of plants reported to be antitumor in Brazil? Have the plant species used for tumor treatment in traditional Brazilian medicine been sufficiently examined scientifically? Our analysis included papers published between 1980 and 2008. A total of 84 medicinal plant species were reported to be used for cancer and tumor prevention or treatment; 69.05% of these were cited as being used for the treatment of tumors and cancer in general and 30.95% for specific tumors or cancers. The plants that were cited at a higher frequency were Aloe vera, Euphorbia tirucalli, and Tabebuia impetiginosa. At least, one pharmacological study was found for 35.71% of the species. Majority of the studies selected were conducted in rural communities and urban areas and in areas with traditional healers in Brazil. We found the following molecules to be the most studied in vitro and in vivo: silibinin, ?-lapachone, plumbagin and capsaicin. The species addressed here constitute interesting objects for future studies to various professionals in the field of natural products. PMID:21528006

de Melo, Joabe Gomes; Santos, Ariane Gaspar; de Amorim, Elba Lúcia Cavalcanti; do Nascimento, Silene Carneiro; de Albuquerque, Ulysses Paulino

2011-01-01

312

Effects of plant virus and its insect vector on Encarsia formosa, a biocontrol agent of whiteflies.  

PubMed

In this study, we investigated the tritrophic interactions among a persistently transmitted plant virus, Tomato yellow leaf curl virus (TYLCV), its insect vector, the sweetpotato whitefly Bemisia tabaci, and a parasitoid, Encarsia formosa Gahan, one of the most extensively used biological control agents. As an emerging invasive pest worldwide, the two most damaging whiteflies are B. tabaci B and Q cryptic species. On healthy tomato plants, parasitoid-induced mortality was significantly higher in B. tabaci B than in Q. In contrast, similar mortality levels of B and Q were observed on TYLCV-infected plants. A higher rate of parasitism was consistently observed in B, independent of the TYLCV infection. Similarly, the life history traits of E. formosa were influenced by both TYLCV and the two cryptic species of B. tabaci. Specifically, E. formosa parasitizing B had a greater adult longevity and shorter developmental time on healthy plants, whereas the parasitoids developing from Q has a greater adult longevity on TYLCV-infected plants. The emergence rate of E. formosa was unaffected by either B. tabaci cryptic species or the virus. These results suggest that the vector-borne pathogen can manipulate the host suitability of a parasitoid and hence the parasitoid-host interactions. PMID:25096549

Liu, Xiaoyuan; Xiang, Wensheng; Jiao, Xiaoguo; Zhang, Youjun; Xie, Wen; Wu, Qingjun; Zhou, Xuguo; Wang, Shaoli

2014-01-01

313

Medicinal Plants Used as Antitumor Agents in Brazil: An Ethnobotanical Approach  

PubMed Central

We describe the medicinal plants that have been reported to be antitumor agents and that have been used in ethnobotanic research in Brazil to answer the following questions: what is the abundance of plants reported to be antitumor in Brazil? Have the plant species used for tumor treatment in traditional Brazilian medicine been sufficiently examined scientifically? Our analysis included papers published between 1980 and 2008. A total of 84 medicinal plant species were reported to be used for cancer and tumor prevention or treatment; 69.05% of these were cited as being used for the treatment of tumors and cancer in general and 30.95% for specific tumors or cancers. The plants that were cited at a higher frequency were Aloe vera, Euphorbia tirucalli, and Tabebuia impetiginosa. At least, one pharmacological study was found for 35.71% of the species. Majority of the studies selected were conducted in rural communities and urban areas and in areas with traditional healers in Brazil. We found the following molecules to be the most studied in vitro and in vivo: silibinin, ?-lapachone, plumbagin and capsaicin. The species addressed here constitute interesting objects for future studies to various professionals in the field of natural products. PMID:21528006

de Melo, Joabe Gomes; Santos, Ariane Gaspar; de Amorim, Elba Lúcia Cavalcanti; do Nascimento, Silene Carneiro; de Albuquerque, Ulysses Paulino

2011-01-01

314

Effects of plant virus and its insect vector on Encarsia formosa, a biocontrol agent of whiteflies  

PubMed Central

In this study, we investigated the tritrophic interactions among a persistently transmitted plant virus, Tomato yellow leaf curl virus (TYLCV), its insect vector, the sweetpotato whitefly Bemisia tabaci, and a parasitoid, Encarsia formosa Gahan, one of the most extensively used biological control agents. As an emerging invasive pest worldwide, the two most damaging whiteflies are B. tabaci B and Q cryptic species. On healthy tomato plants, parasitoid-induced mortality was significantly higher in B. tabaci B than in Q. In contrast, similar mortality levels of B and Q were observed on TYLCV-infected plants. A higher rate of parasitism was consistently observed in B, independent of the TYLCV infection. Similarly, the life history traits of E. formosa were influenced by both TYLCV and the two cryptic species of B. tabaci. Specifically, E. formosa parasitizing B had a greater adult longevity and shorter developmental time on healthy plants, whereas the parasitoids developing from Q has a greater adult longevity on TYLCV-infected plants. The emergence rate of E. formosa was unaffected by either B. tabaci cryptic species or the virus. These results suggest that the vector-borne pathogen can manipulate the host suitability of a parasitoid and hence the parasitoid-host interactions. PMID:25096549

Liu, Xiaoyuan; Xiang, Wensheng; Jiao, Xiaoguo; Zhang, Youjun; Xie, Wen; Wu, Qingjun; Zhou, Xuguo; Wang, Shaoli

2014-01-01

315

Lepidopterans as Potential Agents for the Biological Control of the Invasive Plant, Miconia calvescens  

PubMed Central

This work investigated eight species of Lepidoptera associated with Miconia calvescens DC. (Myrtales: Melastomataceae) in Brazil, including six defoliators, Salbia lotanalis Druce (Lepidoptera: Pyralidae), Druentia inscita Schaus (Mimallonidae), Antiblemma leucocyma Hampson (Noctuidae), three Limacodidae species, a fruit borer Carposina cardinata Meyrick (Carposinidae), and a damager of flowers Pleuroprucha rudimentaria Guenée (Geometridae). Based on host specificity and the damage caused to plants, S. lotanalis and D. inscita are the most promising species for biological control of M. calvescens. Furthermore, if C. cardinata and P. rudimentaria have host specificity in future tests, these caterpillars could also be considered as appropriate biocontrol agents. PMID:22938203

Morais, Elisangela G.F.; Picanço, Marcelo C.; Semeão, Altair A.; Barreto, Robert W.; Rosado, Jander F.; Martins, Julio C.

2012-01-01

316

Group 11 Metal Compounds with Tripodal Bis(imidazole) Thioether Ligands. Applications as Catalysts in the Oxidation of Alkenes and as Antimicrobial Agents  

PubMed Central

New group 11 metal complexes have been prepared using the previously described tripodal bis(imidazole) thioether ligand (N-methyl-4,5-diphenyl-2-imidazolyl)2C(OMe)C(CH3)2S(tert-Bu) ({BITOMe,StBu}, 2). The pincer ligand offers a N2S donor atom set that can be used to coordinate the group 11 metals in different oxidation states [AuI, AuIII, AgI, CuI and CuII]. Thus the new compounds [Au{BITOMe,StBu}Cl][AuCl4]2 (3), [Au{BITOMe,StBu}Cl] (4), [Ag{BITOMe,StBu}X] (X = OSO2CF3 ? 5, PF6 ? 6) and [Cu{BITOMe,StBu}Cl2] (7) have been synthesized from reaction of 2 with the appropriate metal precursors, and characterized in solution. While attempting characterization in the solid state of 3, single crystals of the neutral dinuclear mixed AuIII-AuI species [Au2{BITOMe,S}Cl3] (8) were obtained and its crystal structure was determined by X-ray diffraction studies. The structure shows a AuIII center coordinated to the pincer ligand through one N and the S atom. The soft AuI center coordinates to the ligand through the same S atom that has lost the tert-butyl group, thus becoming a thiolate ligand. The short distance between the AuI–AuIII atoms (3.383 Å) may indicate a weak metal-metal interaction. Complexes 2–7 and the previously described CuI compound [Cu{BITOMe,StBu}]PF6 (9) have been evaluated in the oxidation of biphenyl ethylene with tert-butyl hydrogen peroxide (TBHP) as the oxidant. Results have shown that the AuI and AgI complexes 4 and 6 (at 10 mol % loading) are the more active catalysts in this oxidative cleavage. The antimicrobial activity of compounds 2–5, 7 and 9 against Gram-positive and Gram-negative bacteria and yeast has also been evaluated. The new gold and silver compounds display moderate to high antibacterial activity, while the copper derivatives are mostly inactive. The gold and silver complexes were also potent against fungi. Their cytotoxic properties have been analyzed in vitro utilizing HeLa human cervical carcinoma cells. The compounds displayed a very low cytotoxicity on this cell line (5 to 10 times lower than cisplatin) and on normal primary cells derived from C57B6 mouse muscle explants, which may make them promising candidates as potential antimicrobial agents and safer catalysts due to low toxicity in human and other mammalian tissues. PMID:25134773

Liu, Fangwei; Anis, Reema; Hwang, Eunmi; Ovalle, Rafael; Varela-Ramírez, Armando; Aguilera, Renato J.; Contel, María

2011-01-01

317

Enhancing Potentially Plant-Available Lead Concentrations in Contaminated Residential Soils Using a Biodegradable Chelating Agent  

NASA Astrophysics Data System (ADS)

Chelation of heavy metals is an important factor in enhancing metal solubility and, hence, metal availability to plants to promote phytoremediation. In the present study, we compared the effects of application of a biodegradable chelating agent, namely, ethylenediaminedisuccinic acid (EDDS) on enhancing plant available form of lead (Pb) in Pb-based paint contaminated residential soils compared to that of a more commonly used, but non-biodegradable chelate, i.e., ethylenediaminetetraacetic acid (EDTA). Development of a successful phytoremediation model for metals such as Pb depends on a thorough understanding of the physical and chemical properties of the soil, along with the optimization of a chelate treatment to mobilize Pb from `unavailable' pools to potentially plant available fraction. In this context, we set out to perform batch incubation experiments to investigate the effectiveness of the two aforementioned chelates in enhancing plant available Pb at four different concentrations (0, 5, 10 and 15 mM/kg soil) and three treatment durations (0, 10 and 30 days). We selected 12 contaminated residential soils from two major metropolitan areas (San Antonio, TX and Baltimore, MD) with varying soil physico-chemical properties - the soils from San Antonio were primarily alkaline and those from Baltimore were typically acidic. Total soil Pb concentrations ranged between 256 mg/kg and 4,182 mg/kg. Our results show that both chelates increased the solubility of Pb, otherwise occluded in the complex soil matrix. For both EDTA and EDDS, the exchangeable concentrations of soil Pb also increased with increase in chelate concentration and incubation time. The most effective treatment was 15 mM chelate kg-1 soil incubated for 30 days, which caused many fold increase in potentially plant available Pb (a combination of the soluble and exchangeable fractions) relative to the unamended controls. Step wise multiple linear regression analysis using chelate-extractable Pb and soil properties showed that plant available Pb fraction could be assessed from the two inter-related soil parameters: soil organic matter and soil pH. Although EDTA was more effective in Pb solubilization than EDDS, the rapid kinetics of the Pb-EDTA complexation process and the prolonged persistence of EDTA in soils pose a potential groundwater contamination problem via metal leaching. In contrast to EDTA, EDDS addition caused relatively slow release of Pb from the soil matrix. The biodegradable nature (and short half life) of EDDS in soils makes it a promising chelating agent for use as soil amendment to enhance Pb solubilization and hence, potential plant uptake.

Andra, S.; Datta, R.; Sarkar, D.; Saminathan, S.

2007-12-01

318

Antimicrobial peptides  

PubMed Central

With increasing antibiotics resistance, there is an urgent need for novel infection therapeutics. Since antimicrobial peptides provide opportunities for this, identification and optimization of such peptides have attracted much interest during recent years. Here, a brief overview of antimicrobial peptides is provided, with focus placed on how selected hydrophobic modifications of antimicrobial peptides can be employed to combat also more demanding pathogens, including multi-resistant strains, without conferring unacceptable toxicity. PMID:24758244

2014-01-01

319

Green synthesis of gold nanoparticles using plant extracts as reducing agents  

PubMed Central

Gold nanoparticles (GNPs) were prepared using four different plant extracts as reducing and stabilizing agents. The extracts were obtained from the following plants: Salvia officinalis, Lippia citriodora, Pelargonium graveolens and Punica granatum. The size distributions of the GNPs were measured using three different methods: dynamic light scattering, nanoparticle-tracking analysis and analysis of scanning electron microscopy images. The three methods yielded similar size distributions. Biocompatibility was examined by correlation of L-cell growth in the presence of different amounts of GNPs. All GNPs showed good biocompatibility and good stability for over 3 weeks. Therefore, they can be used for imaging and drug-delivery applications in the human body. High-resolution transmission electron microscopy was used to view the shapes of the larger GNPs, while infrared spectroscopy was employed to characterize the various functional groups in the organic layer that stabilize the particles. Finally, active ingredients in the plant extract that might be involved in the formation of GNPs are proposed, based on experiments with pure antioxidants that are known to exist in that plant. PMID:25187704

Elia, Paz; Zach, Raya; Hazan, Sharon; Kolusheva, Sofiya; Porat, Ze’ev; Zeiri, Yehuda

2014-01-01

320

Green synthesis of gold nanoparticles using plant extracts as reducing agents.  

PubMed

Gold nanoparticles (GNPs) were prepared using four different plant extracts as reducing and stabilizing agents. The extracts were obtained from the following plants: Salvia officinalis, Lippia citriodora, Pelargonium graveolens and Punica granatum. The size distributions of the GNPs were measured using three different methods: dynamic light scattering, nanoparticle-tracking analysis and analysis of scanning electron microscopy images. The three methods yielded similar size distributions. Biocompatibility was examined by correlation of L-cell growth in the presence of different amounts of GNPs. All GNPs showed good biocompatibility and good stability for over 3 weeks. Therefore, they can be used for imaging and drug-delivery applications in the human body. High-resolution transmission electron microscopy was used to view the shapes of the larger GNPs, while infrared spectroscopy was employed to characterize the various functional groups in the organic layer that stabilize the particles. Finally, active ingredients in the plant extract that might be involved in the formation of GNPs are proposed, based on experiments with pure antioxidants that are known to exist in that plant. PMID:25187704

Elia, Paz; Zach, Raya; Hazan, Sharon; Kolusheva, Sofiya; Porat, Ze'ev; Zeiri, Yehuda

2014-01-01

321

Improvement of water treatment pilot plant with Moringa oleifera extract as flocculant agent.  

PubMed

Moringa oleifera extract is a high-capacity flocculant agent for turbidity removal in surface water treatment. A complete study of a pilot-plant installation has been carried out. Because of flocculent sedimentability of treated water, a residual turbidity occured in the pilot plant (around 30 NTU), which could not be reduced just by a coagulation-flocculation-sedimentation process. Because of this limitation, the pilot plant (excluded filtration) achieved a turbidity removal up to 70%. A slow sand filter was put in as a complement to installation. A clogging process was characterized, according to Carman-Kozeny's hydraulic hypothesis. Kozeny's k parameter was found to be 4.18. Through fouling stages, this k parameter was found to be up to 6.36. The obtained data are relevant for the design of a real filter in a continuous-feeding pilot plant. Slow sand filtration is highly recommended owing to its low cost, easy-handling and low maintenance, so it is a very good complement to Moringa water treatment in developing countries. PMID:19603700

Beltrán-Heredia, J; Sánchez-Martín, J

2009-05-01

322

Synergistic activities of a silver(I) glutamic acid complex and reactive oxygen species (ROS): a novel antimicrobial and chemotherapeutic agent.  

PubMed

The antimicrobial and chemotherapeutic activities of a silver(I) glutamic acid complex with the synergistic concomitant generation of reactive oxygen species (ROS) were investigated here. The ROS generation system employed was via Fenton chemistry. The antimicrobial and chemotherapeutic activities were investigated on Staphylococcus aureus ATCC 43300 and Escherichia coli bacteria, and Vero and MCF-7 tumor cell lines, respectively. Antimicrobial activities were conducted by determining minimum inhibitory concentration (MIC), while chemotherapeutic efficacies were done by serial dilution using standard techniques to determine the half maximal inhibitory concentration (IC50). The antimicrobial and chemotherapeutic results obtained were compared with positive control drugs gentamicin, oxacillin, penicillin, streptomycin and cisplatin, a ubiquitously used platinum-based antitumor drug, and with the silver(I) glutamic acid complex and hydrogen peroxide separately. Based on MIC and IC50 values, it was determined that this synergistic approach was very effective at extremely low concentrations, especially when compared with the other drugs evaluated here. This finding might be of great significance regarding metronomic dosing when this synergistic approach is clinically implemented. Since silver at low concentrations exhibits no toxic, mutagenic and carcinogenic activities, this might offer an alternative approach for the development of safer silver-based antimicrobial and chemotherapeutic drugs, thereby reducing or even eliminating the toxicity associated with current drugs. Accordingly, the present approach might be integrated into the systemic clinical treatment of infectious diseases and cancer. PMID:22680634

Batarseh, K I; Smith, M A

2012-01-01

323

Triorganotin compounds as antimicrobial agents.  

PubMed

Six triorganotin derivatives of thiolupinine(1-mercaptolupinane), 2-mercaptobenzoxazole and 2-mercaptobenzothiazole were prepared and tested against several bacteria, fungi and protozoa. Most compounds exhibited high activity against the tested microorganisms and particularly worth noting was the activity of triethyltin lupinylsulfide on Gram-negative strains. Triethylgermanium lupinylsulfide was also prepared but was devoid of action on the whole set of tested microorganisms. PMID:10384717

Novelli, F; Recine, M; Sparatore, F; Juliano, C

1999-04-30

324

Natural Flavonoids as Antimicrobial Agents  

Microsoft Academic Search

The present report is a review of flavonoids that have a proven inhibitory activity against a variety of human pathogens, including antibiotic-resistant Gram-positive and Gram-negative bacteria and viruses.

W. Bylka; I. Matlawska; N. A. Pilewski

325

Contribution of endogenous plant myrosinase to the antimicrobial activity of deodorized mustard against Escherichia coli O157:H7 in fermented dry sausage.  

PubMed

This work investigated the antimicrobial activity of residual endogenous plant myrosinase in Oriental and yellow mustard powders and a deoiled meal (which contained more glucosinolate than unextracted mustard powder of each type of mustard), against Escherichia coli O15:H7 during dry-fermented sausage ripening. When small amounts of "hot" mustard powder or meal containing endogenous plant myrosinase were added to fully-deodorized powders and a meal of the same type, pathogen reduction rates were enhanced. The higher glucosinolate level in the deoiled mustard meal enabled the use of 50% less mustard in dry sausage to achieve the mandatory ?5logCFU/g reduction of E. coli O157:H7. The myrosinase-like activity present in E. coli O157:H7 contributed to glucosinolate hydrolysis in sausages with fully-deodorized, deoiled mustard meal, although the period necessary for a 5log pathogen reduction was 14d longer. Yellow mustard derivatives were more potently antimicrobial than Oriental mustard. PMID:25150670

Cordeiro, Roniele Peixoto; Wu, Chen; Holley, Richard Alan

2014-10-17

326

Antimicrobial stewardship in patients with cancer.  

PubMed

Consensus guidelines recommend antimicrobial stewardship in all hospitals with the following goals in mind: appropriate and judicious use of antimicrobial agents leading to increased drug safety, reduced antimicrobial utilization, reduction in the development and selection of resistant organisms, cost containment, and improved patient outcomes. Patients with cancer, especially those with hematologic malignancies and neutropenia, develop serious infections often and receive antimicrobial therapy frequently. Consequently, there is considerable opportunity to practice antimicrobial stewardship in this population. Several antimicrobial stewardship strategies such as antimicrobial restriction, cycling, prospective audit and feedback, and de-escalation have been evaluated in patients with cancer. The primary focus has been on the prevention and treatment of bacterial infections in febrile neutropenic patients. These efforts should be expanded to include fungal, viral, and other infections. PMID:23307520

Tverdek, Frank P; Rolston, Kenneth V; Chemaly, Roy F

2012-08-01

327

Apple, carrot, and hibiscus edible films containing plant antimicrobials inactivate Salmonella Newport in packaged organic leafy greens  

Technology Transfer Automated Retrieval System (TEKTRAN)

The increased demand for organic leafy green may raise the risk of foodborne illness outbreaks due to consumption of contaminated produce. Edible films incorporated with natural antimicrobials have the potential to be used as ingredients into organic bagged salads to control contamination from path...

328

In-vitro antimicrobial activity screening of some ethnoveterinary medicinal plants traditionally used against mastitis, wound and gastrointestinal tract complication in Tigray Region, Ethiopia  

PubMed Central

Objective To screen the antibacterial activity of nine ethnoveterinary plants traditionally used for the treatment of mastitis, wound and gastrointestinal complications. Methods Hydroalcoholic exctracts of medicinal plants namely, Achyranthes aspera (A. aspera) L. (Family Asparagaceae), Ficus caria (F. caria) (Family Moraceae), Malvi parviflora (M. parviflora) (Family Malvaceae), Vernonia species (V. species) (local name Alakit, Family Asteraceae), Solanum hastifolium (S. hastifolium) (Family Solanaceae), Calpurinia aurea (C. aurea) (Ait) Benth (Family Fabaceae), Nicotiana tabacum (N. tabacum) L. (Family Solanaceae), Ziziphus spina-christi (Z. spina-christi) (Family Rhamnaceae), Croton macrostachys (C. macrostachys) (Family Euphorbiaceae), were screened against clinical bacterial isolates of veterinary importance from October 2007 to April 2009. The antibacterial activity was tested using disc diffusion at two concentrations (200 mg/mL and 100 mg/mL) and broth dilution methods using 70% methanol macerated leaf extracts. Results With the exception of S. hastifolium all plant extracts exhibited antibacterial activity. Among the medicinal plants tested C. aurea, C. macrostachyus, A. aspera, N. tabacum and vernonia species (Alakit) showed the most promising antimicrobial properties. Conclusions It can be concluded that many of the tested plants have antibacterial activity and supports the traditional usage of the plants for mastitis, wound and gastrointestinal complications treatment. Further studies into their toxicity and phytochemistry is advocated. PMID:23569962

Kalayou, Shewit; Haileselassie, Mekonnen; Gebre-egziabher, Gebremedhin; Tiku'e, Tsegay; Sahle, Samson; Taddele, Habtamu; Ghezu, Mussie

2012-01-01

329

Methods of Antimicrobial Coating of Diverse Materials  

NASA Technical Reports Server (NTRS)

Methods of coating diverse substrate materials with antimicrobial agents have been developed. Originally intended to reduce health risks to astronauts posed by pathogenic microorganisms that can grow on surfaces in spacecraft, these methods could also be used on Earth for example, to ensure sterility of surgical inserts and other medical equipment. The methods involve, generally, chemical preparation of substrate surfaces to enable attachment of antimicrobial molecules to the substrate surfaces via covalent bonds. Substrate materials that have been treated successfully include aluminum, glass, a corrosion-resistant nickel alloy, stainless steel, titanium, and poly(tetrafluoroethylene). Antimicrobial agents that have been successfully immobilized include antibiotics, enzymes, bacteriocins, bactericides, and fungicides. A variety of linkage chem istries were employed. Activity of antimicrobial coatings against gram-positive bacteria, gram-negative bacteria, and fungi was demonstrated. Results of investigations indicate that the most suitable combination of antimicrobial agent, substrate, and coating method depends upon the intended application.

Akse, James R.; Holtsnider, John T.; Kliestik, Helen

2011-01-01

330

Agent-Based Modleing of Power Plants Placement to Evaluate the Clean Energy Standard Goal  

SciTech Connect

There is a political push for utilities to supply a specified share of their electricity sales from clean energy resources under the clean energy standard (CES). The goal is to achieve 80% clean energy by 2035. However, there are uncertainties about the ability of the utility industry to ramp up quickly even with the incentives that will be provided. Water availability from the streams is one of the major factors. The contiguous United States is divided into eighteen water regions, and multiple states share water from a single water region. Consequently, water usage decisions made in one state (located upstream of a water region that crosses multiple states) will greatly impact what is available downstream in another state. In this paper, an agent-based modeling approach is proposed to evaluate the clean energy standard goal for water-dependent energy resources. Specifically, using a water region rather than a state boundary as a bounding envelope for the modeling and starting at the headwaters, virtual power plants are placed based on the conditions that there is: (i) suitable land to site a particular power plant, (ii) enough water that meet regulatory guidelines within 20 miles of the suitable land, and (iii) a 20-mile buffer zone from an existing or a virtual power plant. The results obtained are discussed in the context of the proposed clean energy standard goal for states that overlap with one water region.

Omitaomu, Olufemi A [ORNL] [ORNL

2014-01-01

331

Occupational exposure to solid chemical agents in biomass-fired power plants and associated health effects.  

PubMed

Occupational exposure to aluminium, arsenic, lead, cadmium, and manganese can increase the risk of numerous neurophysiological changes in workers, and may lead to conditions resembling Parkinson's and Alzheimer's disease. However, although the health hazard aspect of these agents has been examined, biomass-fired power plant workers' exposure to them remains a neglected issue. The purpose of this study was to measure maintenance and ash removal workers' multiple exposures to inhalable dust, metals, and crystalline silica during their work tasks in biomass-fired power plants. Maintenance and ash removal workers were exposed to high inhalable dust concentrations inside biomass-fired boilers. The median air inhalable dust concentration in workers' breathing zones were 33 mg m(-3) and 120 mg m(-3) in ash removal and maintenance tasks, respectively. The median concentration of manganese (0.31 mg m(-3)) exceeded the occupational exposure limit in worker's breathing zone samples in maintenance tasks. The most evident exposure-associated health risk from multiple exposures to metals was that of cancer, followed by central nervous system disorders, lower respiratory tract irritation, and finally upper respiratory tract irritation. To avoid the above mentioned health effects, powered air respirators with ABEK+P3 cartridges and carbon monoxide gas detectors are recommended as the minimum requirement for these work tasks. A compressed air breathing apparatus is the best form of protection for the most demanding work phases inside boilers in biomass-fired power plants. PMID:24289933

Jumpponen, M; Rönkkömäki, H; Pasanen, P; Laitinen, J

2014-06-01

332

Use of antimicrobials in veterinary medicine and mechanisms of resistance  

Microsoft Academic Search

This review deals with the application of antimicrobial agents in veterinary medicine and food animal production and the possible consequences arising from the widespread and multi- purpose use of antimicrobials. The various mechanisms that bacteria have developed to escape the inhibitory effects of the antimicrobials most frequently used in the veterinary field are reported in detail. Resistance of bacteria to

Stefan Schwarz; Elisabeth Chaslus-Dancla

2001-01-01

333

ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, June 2011, p. 30583062 Vol. 55, No. 6 0066-4804/11/$12.00 doi:10.1128/AAC.01667-10  

E-print Network

defense peptides--for activity against Mycobacterium tuberculosis and assessed their cytotoxicity therapeutic reg- imen has led to the inevitable emergence of multidrug-resis- tant (MDR) strains of M. Naturally occurring antimicrobial peptides (AMPs), also known as host defense peptides, serve as the first

Barron, Annelise E.

334

Antimicrobial activity of spherical silver nanoparticles prepared using a biocompatible macromolecular capping agent: evidence for induction of a greatly prolonged bacterial lag phase  

Technology Transfer Automated Retrieval System (TEKTRAN)

We have evaluated the antimicrobial properties of Ag-based nanoparticles (Np) using two solid platform-based bioassays and found that 10-20 uL of 0.3-3 uM keratin-based Nps (depending on the starting bacteria concentration = CI) completely inhibited the growth of an equivalent volume of ca. 1,000 to...

335

Antimicrobial, antioxidant, antitumour-promoting and cytotoxic activities of different plant part extracts of Garcinia atroviridis Griff. ex T. Anders  

Microsoft Academic Search

Crude extracts (methanol) of various parts, viz. the leaves, fruits, roots, stem and trunk bark, of Garcinia atroviridis were screened for antimicrobial, cytotoxic, brine shrimp toxic, antitumour-promoting and antioxidant activities. The crude extracts exhibited predominantly antibacterial activity with the root extract showing the strongest inhibition against the test bacteria at a minimum inhibitory dose (MID) of 15.6 ?g\\/disc. Although all

M. M Mackeen; A. M Ali; N. H Lajis; K Kawazu; Z Hassan; M Amran; M Habsah; L. Y Mooi; S. M Mohamed

2000-01-01

336

Efficacy of plant-derived compounds combined with hydrogen peroxide as antimicrobial wash and coating treatment for reducing Listeria monocytogenes on cantaloupes.  

PubMed

The efficacy of four plant-derived antimicrobials (PDAs), namely carvacrol, thymol, ?-resorcylic acid, and caprylic acid, with or without hydrogen peroxide (HP), as antimicrobial wash and chitosan based coating for reducing Listeria monocytogenes (LM) on cantaloupes was investigated. Cantaloupe rind plugs inoculated with LM (10(7) CFU/cm(2)) were washed for 3, 6, 10 min at 25 °C or 1, 3, 5 min at 55 or 65 °C in water, or water containing 2% PDAs with or without 2% HP. Additionally, inoculated cantaloupes (10(8) CFU/fruit) washed with 2% PDA-HP combinations at 55 or 65 °C (5 min) were cut into rindless cubical pieces, stored at 4 °C for 7 days and sampled for LM. Furthermore, inoculated plugs coated with 2% PDAs were stored for 7 days and sampled for surviving LM. Individual PDA washes reduced LM on rinds by ?2.5 log CFU/cm(2) by 3 min (P < 0.05). PDA-HP combinations decreased LM to undetectable levels by 5 min at 55, 65 °C, and 10 min at 25 °C (P < 0.05) and reduced LM transfer from cantaloupe surface to interior (P < 0.0001). All PDA coating treatments reduced LM on cantaloupe to undetectable levels by 5 days (P < 0.05). Results indicate that PDAs alone, or with HP could be used to reduce LM on cantaloupes. PMID:25084644

Upadhyay, Abhinav; Upadhyaya, Indu; Mooyottu, Shankumar; Kollanoor-Johny, Anup; Venkitanarayanan, Kumar

2014-12-01

337

Antimicrobial implications of vitamin D  

PubMed Central

Evidence exists that vitamin D has a potential antimicrobial activity and its deficiency has deleterious effects on general well-being and longevity. Vitamin D may reduce the risk of infection through multiple mechanisms. Vitamin D boosts innate immunity by modulating production of anti-microbial peptides (AMPs) and cytokine response. Vitamin D and its analogues via these mechanisms are playing an increasing role in the management of atopic dermatitis, psoriasis, vitiligo, acne and rosacea. Vitamin D may reduce susceptibility to infection in patients with atopic dermatitis and the ability to regulate local immune and inflammatory responses offers exciting potential for understanding and treating chronic inflammatory dermatitides. Moreover, B and T cell activation as well as boosting the activity of monocytes and macrophages also contribute to a potent systemic anti-microbial effect. The direct invasion by pathogenic organisms may be minimized at sites such as the respiratory tract by enhancing clearance of invading organisms. A vitamin D replete state appears to benefit most infections, with the possible noteworthy exception of Leishmaniasis. Antibiotics remain an expensive option and misuse of these agents results in significant antibiotic resistance and contributes to escalating health care costs. Vitamin D constitutes an inexpensive prophylactic option and possibly therapeutic product either by itself or as a synergistic agent to traditional antimicrobial agents. This review outlines the specific antimicrobial properties of vitamin D in combating a wide range of organisms. We discuss the possible mechanisms by which vitamin D may have a therapeutic role in managing a variety of infections. PMID:22259647

Youssef, Dima A; Miller, Christopher WT; El-Abbassi, Adel M; Cutchins, Della C; Cutchins, Coleman; Grant, William B

2011-01-01

338

Antimicrobial Resistance Mechanisms among Campylobacter  

PubMed Central

Campylobacter jejuni and Campylobacter coli are recognized as the most common causative agents of bacterial gastroenteritis in the world. Humans most often become infected by ingesting contaminated food, especially undercooked chicken, but also other sources of bacteria have been described. Campylobacteriosis is normally a self-limiting disease. Antimicrobial treatment is needed only in patients with more severe disease and in those who are immunologically compromised. The most common antimicrobial agents used in the treatment of Campylobacter infections are macrolides, such as erythromycin, and fluoroquinolones, such as ciprofloxacin. Tetracyclines have been suggested as an alternative choice in the treatment of clinical campylobacteriosis but in practice are not often used. However, during the past few decades an increasing number of resistant Campylobacter isolates have developed resistance to fluoroquinolones and other antimicrobials such as macrolides, aminoglycosides, and beta-lactams. Trends in antimicrobial resistance have shown a clear correlation between use of antibiotics in the veterinary medicine and animal production and resistant isolates of Campylobacter in humans. In this review, the patterns of emerging resistance to the antimicrobial agents useful in treatment of the disease are presented and the mechanisms of resistance to these drugs in Campylobacter are discussed. PMID:23865047

2013-01-01

339

Effect of host-plant genotypes on the performance of three candidate biological control agents of Schinus terebinthifolius in Florida.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Brazilian pepper is a weed in Florida, California and Hawaii that originates from South America. In Florida we have found two distinct types of Brazilian pepper plant and a hybrid between these two types. To control this weed, three biological control agents are being evaluated from Brazil. These ar...

340

Plant size preference of Agapeta zoegana L. (Lepidoptera: Tortricidae), a root-feeding biological control agent of spotted knapweed  

Microsoft Academic Search

Agapeta zoegana L. (Lepidoptera: Tortricidae) is an oligophagous herbivore that was introduced to North America as a biological control agent of spotted knapweed, Centaurea stoebe L. subsp. micranthos (Gugler) Hayek (often called Centaurea maculosa Lam.). Spotted knapweed is a perennial plant that usually increases in size each year. A previous field study reported that more larvae were found on larger

L. Smith; J. M. Story

2003-01-01

341

In vitro anti-microbial activity of the Cuban medicinal plants Simarouba glauca DC, Melaleuca leucadendron L and Artemisia absinthium L.  

PubMed

In the present study, an extensive in vitro antimicrobial profiling was performed for three medicinal plants grown in Cuba, namely Simarouba glauca, Melaleuca leucadendron and Artemisia absinthium. Ethanol extracts were tested for their antiprotozoal potential against Trypanosoma b. brucei, Trypanosoma cruzi, Leishmania infantum and Plasmodium falciparum. Antifungal activities were evaluated against Microsporum canis and Candida albicans whereas Escherichia coli and Staphylococcus aureus were used as test organisms for antibacterial activity. Cytotoxicity was assessed against human MRC-5 cells. Only M. leucadendron extract showed selective activity against microorganisms tested. Although S. glauca exhibited strong activity against all protozoa, it must be considered non-specific. The value of integrated evaluation of extracts with particular reference to selectivity is discussed. PMID:18949336

Valdés, Aymé Fernández-Calienes; Martínez, Judith Mendiola; Lizama, Ramón Scull; Vermeersch, Marieke; Cos, Paul; Maes, Louis

2008-09-01

342

Comparative In Vitro Activities of SMT19969, a New Antimicrobial Agent, against 162 Strains from 35 Less Frequently Recovered Intestinal Clostridium Species: Implications for Clostridium difficile Recurrence  

PubMed Central

We determined the comparative activity of SMT19969 (SMT) against 162 strains representing 35 well-characterized Clostridium species in clusters I to XIX and 13 Clostridium species that had no 16S rRNA match. SMT MICs ranged from 0.06 to >512 ?g/ml and were not species related. SMT might have less impact on normal gut microbiota than other Clostridium difficile infection (CDI) antimicrobials. PMID:24247123

Citron, Diane M.; Tyrrell, Kerin L.

2014-01-01

343

Antimicrobial peptides of multicellular organisms  

Microsoft Academic Search

Multicellular organisms live, by and large, harmoniously with microbes. The cornea of the eye of an animal is almost always free of signs of infection. The insect flourishes without lymphocytes or antibodies. A plant seed germinates successfully in the midst of soil microbes. How is this accomplished? Both animals and plants possess potent, broad-spectrum antimicrobial peptides, which they use to

Michael Zasloff

2002-01-01

344

[In vitro comparative activity (E test) of sparfloxacin and other 8 antimicrobial agents against bacteria isolated from patients with respiratory infections acquired in the community].  

PubMed

Sparfloxacin is a new antimicrobial that, while maintaining a good activity against gram negative bacilli, has a better in vitro activity against gram positive bacteria such as S pneumoniae, intracellular pathogens and anaerobic bacteria. The aim of this work was to study the in vitro activity of sparfloxacin against bacteria isolated from patients with community acquired respiratory infections between October 1994 and January 1995. Using the E-test technique, we studied the susceptibility to sparfloxacin, ciprofloxacin, ampicillin, amoxicillin/clavulanic acid, cefuroxime, cefotaxime, erythromycin, methicillin and nalidixic acid of 50 strains of S pneumoniae, 50 strains of H. influenzae, 50 strains of S aureus and 50 strains of S pyogenes. Sparfloxacin was active against 100% of S pneumoniae, H influenzae and S pyogenes strains. Twenty two percent of S aureus strains were resistant and the MIC 90 was 12 micrograms/ml. Sparfloxacin showed the best in vitro activity against H influenzae and S aureus, a similar activity with ampicillin and cefotaxime against S pneumoniae and a similar activity with ampicillin but superior to all other studied antimicrobial against S pyogenes. It is concluded that sparfloxacin is a good antimicrobial for bacteria isolated from patients with respiratory infections. PMID:8733283

Prado, V; Trucco, O; Nina, A; Salamanca, L; Juliet, C; Braun, S

1995-11-01

345

Antimicrobial hydrogels for the treatment of infection  

PubMed Central

The increasing prevalence of microbial infections, especially those associated with impaired wound healing and biomedical implant failure has spurred the development of new materials having antimicrobial activity. Hydrogels are a class of highly hydrated material finding use in diverse medical applications such as drug delivery, tissue engineering, as wound fillers and as implant coatings, to name a few. The biocompatible nature of many gels make them a convenient starting platform to develop selectively active antimicrobial materials. Hydrogels with antimicrobial properties can be obtained through the encapsulation or covalent immobilization of known antimicrobial agents, or the material itself can be designed to possess inherent antimicrobial activity. In this review we present an overview of antimicrobial hydrogels that have recently been developed and when possible provide a discussion relevant to their mechanism of action. PMID:24122459

Veiga, Ana Salomé; Schneider, Joel P.

2014-01-01

346

Organic extracts from Indigofera suffruticosa leaves have antimicrobial and synergic actions with erythromycin against Staphylococcus aureus  

PubMed Central

A characteristic feature of Staphylococcus aureus is its ability to acquire resistance to antimicrobial agents. There is a need, therefore, for new approaches to combat this pathogen; for example, employing a combination of plant-derived products and antibiotics to overcome bacterial resistance. Indigofera suffruticosa is a plant popularly used to treat infections and has verified antimicrobial action. Here, we investigate the antimicrobial activity of different extracts from I. suffruticosa against S. aureus and their synergistic effects with erythromycin. Leaves of I. suffruticosa were extracted sequentially using diethyl ether, chloroform and acetone and the antimicrobial activity of each extract then tested against nine clinical isolates of S. aureus. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were determined by microdilution tests, while the fractional inhibitory concentration (FIC) was assessed by checkerboard assay. All organic solvent extracts showed antimicrobial activity against S. aureus strains. The acetone extract was the most potent inhibitor of S. aureus (MIC and MBC of 0.78 and 3.12 mg/mL), followed by the chloroform extract (MIC and MBC of 3.12 and 6.25 mg/mL). Furthermore, acetone or chloroform extracts of I. suffruticosa enhanced the activity of erythromycin against S. aureus (FIC ? 0.5). We conclude that organic extracts from leaves of I. suffruticosa, alone or combined with erythromycin, are promising natural products for the development of new anti-S. aureus formulations.

Bezerra dos Santos, Ana Thereza; Araújo, Tiago Ferreira da Silva; Nascimento da Silva, Luis Cláudio; da Silva, Cleideana Bezerra; de Oliveira, Antonio Fernando Morais; Araújo, Janete Magali; Correia, Maria Tereza dos Santos; Lima, Vera Lúcia de Menezes

2015-01-01

347

Cutaneous photosensitivity diseases induced by exogenous agents.  

PubMed

Cutaneous photosensitivity diseases may be idiopathic, produced by endogenous photosensitizers, or associated with exogenous photosensitizers. Those caused by exogenous agents include phototoxicity, photoallergy, and the exacerbation or induction of systemic disorders in which photosensitivity is a prominent clinical manifestation. Phototoxic disorders have a high incidence, whereas photoallergic reactions are much less frequent. The action spectra for most phototoxins and photoallergens lie in the UVA range. Phototoxic and photoallergic reactions can be distinguished on the basis of pathogenesis, clinical characteristics, diagnosis, and management. Drugs capable of causing phototoxic reactions include psoralens, porphyrins, coal tar, antibiotics, and nonsteroidal antiinflammatory agents. Drugs capable of causing photoallergic reactions include topical antimicrobial agents, fragrances, sunscreens, nonsteroidal antiinflammatory agents, plants, and psychiatric medications. Drug-induced systemic diseases in which photosensitivity is a prominent component include drug-induced lupus erythematosus, porphyria, and pellagra. PMID:7673488

Gould, J W; Mercurio, M G; Elmets, C A

1995-10-01

348

Antimicrobial activities of endophytic fungi isolated from Ophiopogon japonicus (Liliaceae)  

PubMed Central

Background Drug resistance in bacteria has become a global concern and the search for new antibacterial agents is urgent and ongoing. Endophytes provide an abundant reservoir of bioactive metabolites for medicinal exploitation, and an increasing number of novel compounds are being isolated from endophytic fungi. Ophiopogon japonicus, containing compounds with antibacterial activity, is a traditional Chinese medicinal plant used for eliminating phlegm, relieving coughs, latent heat in the lungs, and alleviating diabetes mellitus. We investigated the antimicrobial activities of 30 strains of O. japonicus. Methods Fungal endophytes were isolated from roots and stems of O. japonicus collected from Chongqing City, southwestern China. Mycelial extracts (MC) and fermentation broth (FB) were tested for antimicrobial activity using peptide deformylase (PDF) inhibition fluorescence assays and MTT cell proliferation assays. Results A total of 30 endophytic strains were isolated from O. japonicus; 22 from roots and eight from stems. 53.33% of the mycelial extracts (MC) and 33.33% of the fermentation broths (FB) displayed potent inhibition of PDF. 80% of MC and 33.33% of FB significantly inhibited Staphylococcus aureus. 70% of MC and 36.67% of FB showed strong activities against Cryptococcus neoformans. None showed influence on Escherichia coli. Conclusion The secondary metabolites of endophytic fungi from O. japonicus are potential antimicrobial agents. PMID:23190550

2012-01-01

349

Interaction of antimicrobial cyclic lipopeptides from Bacillus subtilis influences their effect on spore germination and membrane permeability in fungal plant pathogens.  

PubMed

Bacillus subtilis cyclic lipopeptides are known to have various antimicrobial effects including different types of interactions with the cell membranes of plant pathogenic fungi. The various spectra of activities of the three main lipopeptide families (fengycins, iturins, and surfactins) seem to be linked to their respective mechanisms of action on the fungal biomembrane. Few studies have shown the combined effect of more than one family of lipopeptides on fungal plant pathogens. In an effort to understand the effect of producing multiple lipopeptide families, sensitivity and membrane permeability of spores from four fungal plant pathogens (Alternaria solani, Fusarium sambucinum, Rhizopus stolonifer, and Verticillium dahliae) were assayed in response to lipopeptides, both individually and as combined treatments. Results showed that inhibition of spores was highly variable depending on the tested fungus-lipopeptide treatment. Results also showed that inhibition of the spores was closely associated with SYTOX stain absorption suggesting effects of efficient treatments on membrane permeability. Combined lipopeptide treatments revealed additive, synergistic or sometimes mutual inhibition of beneficial effects. PMID:25442289

Liu, Jiajie; Hagberg, Ingrid; Novitsky, Laura; Hadj-Moussa, Hanane; Avis, Tyler J

2014-11-01

350

Antimicrobial effects of selected plant essential oils on the growth of a Pseudomonas putida strain isolated from meat.  

PubMed

The inhibitory effect of 60 different essential oils was evaluated on a Pseudomonas putida strain of meat origin, associated with meat spoilage. Essential oils were tested at concentrations from 0.003 to 0.8% (wt/vol) to determine minimum inhibitory and maximal tolerated concentrations (MIC and MTC, respectively) using an agar medium culture. Of the 60 samples tested, Corydothymus capitatus essential oil was the most active showing a MIC of 0.025% and a MTC of 0.06%. Seven essential oils (Cinnamomum cassia, Origanum compactum, Origanum heracleoticum, Satureja hortensis, Satureja montana, Thymus vulgaris carvacroliferum, Thymus vulgaris thymoliferum) have shown a strong antimicrobial activity against P. putida with a MIC of 0.05% and a MTC ranging from 0.013% to 0.025%. Ten other oils (Cinnamomum verum (leaf and bark), Eugenia caryophyllus, Cymbopogon martinii var. motia, Cymbopogon nardus, Melaleuca linariifolia, Origanum majorana, Pimenta dioica, Thymus satureoides, Thymus serpyllum) showed a high antimicrobial activity showing a MIC ranging from 0.1% to 0.4%, while the remaining were less active showing a MIC?0.8%. PMID:22062294

Oussalah, Mounia; Caillet, Stéphane; Saucier, Linda; Lacroix, Monique

2006-06-01

351

Comparative In Vitro Efficacies and Antimicrobial Durabilities of Novel Antimicrobial Central Venous Catheters  

Microsoft Academic Search

We investigated the efficacies and durability of novel antimicrobial central venous catheters (CVCs) in preventing the adherence of microbial organisms to the surfaces of the CVCs. Novel antimicrobial CVCs investigated in this in vitro study were impregnated with antibiotics (minocycline and rifampin), with Oligon agent (silver, platinum, and carbon black), with approved antiseptics (chlorhexidine and silver sulfadiazine), or with a

Hend Hanna; Paul Bahna; Ruth Reitzel; Tanya Dvorak; Gassan Chaiban; Ray Hachem; Issam Raad

2006-01-01

352

Antimicrobial Resistance in Escherichia coli Isolates from Swine and Wild Small Mammals in the Proximity of Swine Farms and in Natural Environments in Ontario, Canada  

Microsoft Academic Search

Wild animals not normally exposed to antimicrobial agents can acquire antimicrobial agent-resistant bacteria through contact with humans and domestic animals and through the environment. In this study we assessed the frequency of antimicrobial resistance in generic Escherichia coli isolates from wild small mammals (mice, voles, and shrews) and the effect of their habitat (farm or natural area) on antimicrobial resistance.

Gosia K. Kozak; Patrick Boerlin; Nicol Janecko; Richard J. Reid-Smith; Claire Jardine

2009-01-01

353

Antimicrobial Peptides: Old Molecules with New Ideas  

Microsoft Academic Search

Almost 90 years have passed since Alexander Fleming discovered the antimicrobial activity of lysozyme, the first natural antibiotic isolated from our body. Since then, various types of molecules with antibiotic activity have been isolated from animals, insects, plants, and bacteria, and their use has revolutionized clinical medicine. So far, more than 1,200 types of peptides with antimicrobial activity have been

Teruaki Nakatsuji; Richard L Gallo

2012-01-01

354

Defensins: antimicrobial peptides of innate immunity  

Microsoft Academic Search

The production of natural antibiotic peptides has emerged as an important mechanism of innate immunity in plants and animals. Defensins are diverse members of a large family of antimicrobial peptides, contributing to the antimicrobial action of granulocytes, mucosal host defence in the small intestine and epithelial host defence in the skin and elsewhere. This review, inspired by a spate of

Tomas Ganz

2003-01-01

355

Cationic Antimicrobial Polymers and Their Assemblies  

PubMed Central

Cationic compounds are promising candidates for development of antimicrobial agents. Positive charges attached to surfaces, particles, polymers, peptides or bilayers have been used as antimicrobial agents by themselves or in sophisticated formulations. The main positively charged moieties in these natural or synthetic structures are quaternary ammonium groups, resulting in quaternary ammonium compounds (QACs). The advantage of amphiphilic cationic polymers when compared to small amphiphilic molecules is their enhanced microbicidal activity. Besides, many of these polymeric structures also show low toxicity to human cells; a major requirement for biomedical applications. Determination of the specific elements in polymers, which affect their antimicrobial activity, has been previously difficult due to broad molecular weight distributions and random sequences characteristic of radical polymerization. With the advances in polymerization control, selection of well defined polymers and structures are allowing greater insight into their structure-antimicrobial activity relationship. On the other hand, antimicrobial polymers grafted or self-assembled to inert or non inert vehicles can yield hybrid antimicrobial nanostructures or films, which can act as antimicrobials by themselves or deliver bioactive molecules for a variety of applications, such as wound dressing, photodynamic antimicrobial therapy, food packing and preservation and antifouling applications. PMID:23665898

Carmona-Ribeiro, Ana Maria; de Melo Carrasco, Letícia Dias

2013-01-01

356

Antimicrobial Activity and Probable Mechanisms of Action of Medicinal Plants of Kenya: Withania somnifera, Warbugia ugandensis, Prunus africana and Plectrunthus barbatus  

PubMed Central

Withania somnifera, Warbugia ugandensis, Prunus africana and Plectrunthus barbatus are used traditionally in Kenya for treatment of microbial infections and cancer. Information on their use is available, but scientific data on their bioactivity, safety and mechanisms of action is still scanty. A study was conducted on the effect of organic extracts of these plants on both bacterial and fungal strains, and their mechanisms of action. Extracts were evaluated through the disc diffusion assay. Bacteria and yeast test strains were cultured on Mueller-Hinton agar and on Sabouraud dextrose agar for the filamentous fungi. A 0.5 McFarland standard suspension was prepared. Sterile paper discs 6 mm in diameter impregnated with 10 µl of the test extract (100 mg/ml) were aseptically placed onto the surface of the inoculated media. Chloramphenicol (30 µg) and fluconazole (25 µg) were used as standards. Discs impregnated with dissolution medium were used as controls. Activity of the extracts was expressed according to zone of inhibition diameter. MIC was determined at 0.78–100 mg/ml. Safety studies were carried using Cell Counting Kit 8 cell proliferation assay protocol. To evaluate extracts mechanisms of action, IEC-6 cells and RT-PCR technique was employed in vitro to evaluate Interleukin 7 cytokine. Investigated plants extracts have both bactericidal and fungicidal activity. W. ugandensis is cytotoxic at IC50<50 µg/ml with MIC values of less than 0.78 mg/ml. Prunus africana shuts down expression of IL 7 mRNA at 50 µg/ml. W. somnifera has the best antimicrobial (1.5625 mg/ml), immunopotentiation (2 times IL 7 mRNA expression) and safety level (IC50>200 µg/ml). Fractions from W. ugandensis and W. somnifera too demonstrated antimicrobial activity. Mechanisms of action can largely be attributed to cytotoxicity, Gene silencing and immunopotentiation. Use of medicinal plants in traditional medicine has been justified and possible mechanisms of action demonstrated. Studies to isolate and characterize the bioactive constituents continue. PMID:23785437

Mwitari, Peter G.; Ayeka, Peter A.; Ondicho, Joyce; Matu, Esther N.; Bii, Christine C.

2013-01-01

357

Genome Sequence of the Plant Pathogen and Biotechnology Agent Agrobacterium tumefaciens C58  

Microsoft Academic Search

Agrobacterium tumefaciens is a plant pathogen capable of transferring a defined segment of DNA to a host plant, generating a gall tumor. Replacing the transferred tumor-inducing genes with exogenous DNA allows the introduction of any desired gene into the plant. Thus, A. tumefaciens has been critical for the development of modern plant genetics and agricultural biotechnology. Here we describe the

Brad Goodner; Gregory Hinkle; Stacie Gattung; Nancy Miller; Mary Blanchard; Barbara Qurollo; Barry S. Goldman; Yongwei Cao; Manor Askenazi; Conrad Halling; Lori Mullin; Kathryn Houmiel; Jeffrey Gordon; Mark Vaudin; Oleg Iartchouk; Andrew Epp; Fang Liu; Clifford Wollam; Mike Allinger; Dahlia Doughty; Charlaine Scott; Courtney Lappas; Brian Markelz; Casey Flanagan; Chris Crowell; Jordan Gurson; Caroline Lomo; Carolyn Sear; Graham Strub; Chris Cielo; Steven Slater

2001-01-01

358

One pot three components microwave assisted and conventional synthesis of new 3-(4-chloro-2-hydroxyphenyl)-2-(substituted) thiazolidin-4-one as antimicrobial agents.  

PubMed

A one-pot, three-component, microwave assisted and conventional synthesis of new 3-(4-chloro-2-hydroxyphenyl)-2-(substituted) thiazolidin-4-one (4a-n) was carried out by using N,N-dimethylformamide as a solvent with high product yield. Among these synthesized compounds (4f, 4g, 4l and 4m) were found to be a broad spectrum molecule active against all bacterial and fungus strains tested, except fungus Aspergillus niger. Amongst the compounds (4g, 4l and 4m) were found to be more potent than respective standard drugs used in the experiment against Candida albicans, Staphylococcus aureus and Aspergillus flavus, respectively. All synthesized compounds were also tested for their cytotoxic activity against HeLa and MCF-7 cell lines by the sulforhodamine B (SRB) assay. This study shows that all compounds were non-cytotoxic in nature, and confirmed their antimicrobial specificity apart from any general cytotoxicity. PMID:24951333

Pansare, Dattatraya N; Mulla, Nayeem A; Pawar, Chandrakant D; Shende, Vikas R; Shinde, Devanand B

2014-08-01

359

Synthesis of silver nanoparticles from stem bark of Cochlospermum religiosum (L.) Alston: an important medicinal plant and evaluation of their antimicrobial efficacy  

NASA Astrophysics Data System (ADS)

The use of different parts of plants for the synthesis of nanoparticles is considered as a green technology as it does not involve any harmful chemicals. Herein, we report on rapid biosynthesis of silver nanoparticles (SNPs) from aqueous stem bark extract of Cochlospermum religiosum a medicinal plant. The reduced silver nanoparticles were characterized by using UV-Visible spectroscopy (UV-Vis), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis, atomic force microscopy, and Fourier transform infrared (FT-IR). The UV-Visible spectrum of the aqueous medium containing silver nanoparticles showed an absorption peak at around 445 nm, XRD showed that the particles are crystalline in nature, with a face-centered cubic structure and the SEM images showed that the spherical-shaped silver nanoparticles were observed and the size range was found to be 20-35 nm. FT-IR spectroscopy analysis revealed that carbohydrate, polyphenols, and protein molecules were involved in the synthesis and capping of silver nanoparticles. These phytosynthesized SNPs were tested for their antimicrobial activity and it analyzed by measuring the inhibitory zone. Cochlospermum religiosum aqueous stem bark extract of SNPs showed highest toxicity to Staphylococcus followed by Pseudomonas, Escherichia coli and Bacillus and lowest toxicity towards Proteus. Whereas in fungal species highest inhibition zone against Aspergillus flavus followed by Rhizopus, Fusarium, and Curvularia, and minimum inhibition zone was observed against Aspergillus niger species. The outcome of this study could be useful for the development of value added products from indigenous medicinal plants of India for nanotechnology-based biomedical applications.

Sasikala, A.; Linga Rao, M.; Savithramma, N.; Prasad, T. N. V. K. V.

2014-11-01

360

Synthetic biology of antimicrobial discovery.  

PubMed

Antibiotic discovery has a storied history. From the discovery of penicillin by Sir Alexander Fleming to the relentless quest for antibiotics by Selman Waksman, the stories have become like folklore used to inspire future generations of scientists. However, recent discovery pipelines have run dry at a time when multidrug-resistant pathogens are on the rise. Nature has proven to be a valuable reservoir of antimicrobial agents, which are primarily produced by modularized biochemical pathways. Such modularization is well suited to remodeling by an interdisciplinary approach that spans science and engineering. Herein, we discuss the biological engineering of small molecules, peptides, and non-traditional antimicrobials and provide an overview of the growing applicability of synthetic biology to antimicrobials discovery. PMID:23654251

Zakeri, Bijan; Lu, Timothy K

2013-07-19

361

Synthetic biology of antimicrobial discovery  

PubMed Central

Antibiotic discovery has a storied history. From the discovery of penicillin by Sir Alexander Fleming to the relentless quest for antibiotics by Selman Waksman, the stories have become like folklore, used to inspire future generations of scientists. However, recent discovery pipelines have run dry at a time when multidrug resistant pathogens are on the rise. Nature has proven to be a valuable reservoir of antimicrobial agents, which are primarily produced by modularized biochemical pathways. Such modularization is well suited to remodeling by an interdisciplinary approach that spans science and engineering. Herein, we discuss the biological engineering of small molecules, peptides, and non-traditional antimicrobials and provide an overview of the growing applicability of synthetic biology to antimicrobials discovery. PMID:23654251

Zakeri, Bijan; Lu, Timothy K.

2012-01-01

362

Animation of Antimicrobial Resistance  

MedlinePLUS Videos and Cool Tools

... 08 Animation of Antimicrobial Resistance (text version) Arabic Translation - Animation of Antimicrobial Resistance (WMV - 19.2MB) Chinese Translation - Animation of Antimicrobial Resistance (WMV - 19.2MB) French ...

363

Antimicrobial peptides: premises and promises  

Microsoft Academic Search

Antimicrobial peptides (AMPs) are an important component of the natural defences of most living organisms against invading pathogens. These are relatively small (<10kDa), cationic and amphipathic peptides of variable length, sequence and structure. During the past two decades several AMPs have been isolated from a wide variety of animals, both vertebrates and invertebrates, and plants as well as from bacteria

K. V. R. Reddy; R. D. Yedery; C. Aranha

2004-01-01

364

ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, July 2010, p. 28932900 Vol. 54, No. 7 0066-4804/10/$12.00 doi:10.1128/AAC.00332-10  

E-print Network

. Cross-Resistance to Nitro Drugs and Implications for Treatment of Human African Trypanosomiasis (NECT) for the treatment of human African trypanosomiasis (HAT) has renewed interest in the potential agents of human African trypanosomiasis (HAT), commonly known as sleeping sick- ness. This epidemic

Schnaufer, Achim

365

Antimicrobial Surfaces  

Microsoft Academic Search

\\u000a In this review, the general principles of antimicrobial surfaces will be discussed in detail. Because many common products\\u000a that keep microbes off surfaces have been banned in the past decade, the search for alternatives is in full run. In recent\\u000a research, numerous new ways to produce so-called self-sterilizing surfaces have been introduced. These technologies are discussed\\u000a with respect to their

Joerg C. Tiller

366

Effect of Plant Derived Antimicrobials on Salmonella Enteritidis Adhesion to and Invasion of Primary Chicken Oviduct Epithelial Cells in vitro and Virulence Gene Expression  

PubMed Central

Salmonella Enteritidis (SE) is a major foodborne pathogen in the United States and one of the most frequently reported Salmonella serotypes globally. Eggs are the most common food product associated with SE infections in humans. The pathogen colonizes the intestinal tract in layers, and migrates to reproductive organs systemically. Since adhesion to and invasion of chicken oviduct epithelial cells (COEC) is critical for SE colonization in reproductive tract, reducing these virulence factors could potentially decrease egg yolk contamination. This study investigated the efficacy of sub-inhibitory concentrations of three plant-derived antimicrobials (PDAs), namely carvacrol, thymol and eugenol in reducing SE adhesion to and invasion of COEC, and survival in chicken macrophages. In addition, the effect of PDAs on SE genes critical for oviduct colonization and macrophage survival was determined using real-time quantitative PCR (RT-qPCR). All PDAs significantly reduced SE adhesion to and invasion of COEC (p < 0.001). The PDAs, except thymol consistently decreased SE survival in macrophages (p < 0.001). RT-qPCR results revealed down-regulation in the expression of genes involved in SE colonization and macrophage survival (p < 0.001). The results indicate that PDAs could potentially be used to control SE colonization in chicken reproductive tract; however, in vivo studies validating these results are warranted. PMID:23698782

Upadhyaya, Indu; Upadhyay, Abhinav; Kollanoor-Johny, Anup; Darre, Michael J.; Venkitanarayanan, Kumar

2013-01-01

367

Determination of antimicrobials in sludge from infiltration basins at two artificial recharge plants by pressurized liquid extraction-liquid chromatography-tandem mass spectrometry.  

PubMed

This work describes the optimization of a multi-residue analytical approach for the simultaneous determination of 11 antimicrobials (9 sulphonamides and 2 penicillins) in sludge from infiltration basins. The method is based on pressurized liquid extraction (PLE) followed by solid-phase extraction (SPE) for pre-concentration and purification, and analysis by liquid chromatography-tandem mass spectrometry using electrospray in the positive ionization mode (LC-(ESI+)-MS/MS). Limits of detections (LODs) between 1 pg/g and 0.2 ng/g and limits of quantifications (LOQs) between 5 pg/g and 0.6 ng/g were achieved. Good recovery values (57.6-104%) were obtained for sulfamethazine, sulfapyridine, sulfadiazine and sulfamethoxypyridazine, while medium recovery values (14-47%) were afforded for sulfadimethoxine, sulfathiazole and sulfamethoxazole. However, only a poor recovery (<1%) could be possible for both penicillins and two sulphonamides, namely nafcillin, dicloxacillin, sulfisoxazole and sulfamethizole. These low recoveries were attributed to the presence of ionic suppression effects (even after thorough extraction and purification) rather than to an inefficient extraction. The method developed was applied to the analysis of sludge samples from the infiltration basins of two artificial recharge plants located in Sweden and Denmark. All target compounds were found to be present in at least one sample. Sulfadimethoxine, nafcillin and dicloxacillin were detected in all the samples analysed. PMID:16822516

Díaz-Cruz, M Silvia; López de Alda, María José; Barceló, Damià

2006-10-13

368

Plant-Derived Antimicrobials Reduce E. coli O157:H7 Virulence Factors Critical for Colonization in Cattle Gastrointestinal Tract In Vitro  

PubMed Central

This study investigated the effect of subinhibitory concentrations (SIC) of five plant-derived antimicrobials (PDAs), namely, trans cinnamaldehyde, eugenol, carvacrol, thymol, and ?-resorcylic acid, on E. coli O157:H7 (EHEC) attachment and invasion of cultured bovine colonic (CO) and rectoanal junction (RAJ) epithelial cells. In addition, PDAs' effect on EHEC genes critical for colonization of cattle gastrointestinal tract (CGIT) was determined in bovine rumen fluid (RF) and intestinal contents (BICs). Primary bovine CO and RAJ epithelial cells were established and were separately inoculated with three EHEC strains with or without (control) SIC of each PDA. Following incubation, EHEC that attached and invaded the cells were determined. Furthermore, the expression of EHEC genes critical for colonization in cattle was investigated using real-time, quantitative polymerase chain reaction in RF and BICs. All the PDAs decreased EHEC invasion of CO and RAJ epithelial cells (P < 0.05). The PDAs also downregulated (P < 0.05) the expression of EHEC genes critical for colonization in CGIT. Results suggest that the PDAs could potentially be used to control EHEC colonization in cattle; however follow-up in vivo studies in cattle are warranted. PMID:25050328

Ananda Baskaran, Sangeetha

2014-01-01

369

Prevention of ventilator-associated pneumonia, mortality and all intensive care unit acquired infections by topically applied antimicrobial or antiseptic agents: a meta-analysis of randomized controlled trials in intensive care units  

PubMed Central

Introduction Given the high morbidity and mortality attributable to ventilator-associated pneumonia (VAP) in intensive care unit (ICU) patients, prevention plays a key role in the management of patients undergoing mechanical ventilation. One of the candidate preventive interventions is the selective decontamination of the digestive or respiratory tract (SDRD) by topical antiseptic or antimicrobial agents. We performed a meta-analysis to investigate the effect of topical digestive or respiratory tract decontamination with antiseptics or antibiotics in the prevention of VAP, of mortality and of all ICU-acquired infections in mechanically ventilated ICU patients. Methods A meta-analysis of randomised controlled trials was performed. The U.S. National Library of Medicine's MEDLINE database, Embase, and Cochrane Library computerized bibliographic databases, and reference lists of selected studies were used. Selection criteria for inclusion were: randomised controlled trials (RCTs); primary studies; examining the reduction of VAP and/or mortality and/or all ICU-acquired infections in ICU patients by prophylactic use of one or more of following topical treatments: 1) oropharyngeal decontamination using antiseptics or antibiotics, 2) gastrointestinal tract decontamination using antibiotics, 3) oropharyngeal plus gastrointestinal tract decontamination using antibiotics and 4) respiratory tract decontamination using antibiotics; reported enough data to estimate the odds ratio (OR) or risk ratio (RR) and their variance; English language; published through June 2010. Results A total of 28 articles met all inclusion criteria and were included in the meta-analysis. The overall estimate of efficacy of topical SDRD in the prevention of VAP was 27% (95% CI of efficacy = 16% to 37%) for antiseptics and 36% (95% CI of efficacy = 18% to 50%) for antibiotics, whereas in none of the meta-analyses conducted on mortality was a significant effect found. The effect of topical SDRD in the prevention of all ICU-acquired infections was statistically significant (efficacy = 29%; 95% CI of efficacy = 14% to 41%) for antibiotics whereas the use of antiseptics did not show a significant beneficial effect. Conclusions Topical SDRD using antiseptics or antimicrobial agents is effective in reducing the frequency of VAP in ICU. Unlike antiseptics, the use of topical antibiotics seems to be effective also in preventing all ICU-acquired infections, while the effectiveness on mortality of these two approaches needs to be investigated in further research. PMID:21702946

2011-01-01

370

Antimicrobial Polymers with Metal Nanoparticles  

PubMed Central

Metals, such as copper and silver, can be extremely toxic to bacteria at exceptionally low concentrations. Because of this biocidal activity, metals have been widely used as antimicrobial agents in a multitude of applications related with agriculture, healthcare, and the industry in general. Unlike other antimicrobial agents, metals are stable under conditions currently found in the industry allowing their use as additives. Today these metal based additives are found as: particles, ions absorbed/exchanged in different carriers, salts, hybrid structures, etc. One recent route to further extend the antimicrobial applications of these metals is by their incorporation as nanoparticles into polymer matrices. These polymer/metal nanocomposites can be prepared by several routes such as in situ synthesis of the nanoparticle within a hydrogel or direct addition of the metal nanofiller into a thermoplastic matrix. The objective of the present review is to show examples of polymer/metal composites designed to have antimicrobial activities, with a special focus on copper and silver metal nanoparticles and their mechanisms. PMID:25607734

Palza, Humberto

2015-01-01

371

Field experiments to evaluate host plant specificity of prospective agents of Onopordum acanthium in Bulgaria  

Technology Transfer Automated Retrieval System (TEKTRAN)

Scotch thistle, Onopordum acanthium, is an invasive alien weed in North America that originates from Europe. Previous field observations in Bulgaria have confirmed the presence of prospective biological control agents including Cassida rubiginosa, Chaetostomella cylindrica, Eublemma amoena, Larinus ...

372

Genome sequence of the plant pathogen and biotechnology agent Agrobacterium tumefaciens C58.  

PubMed

Agrobacterium tumefaciens is a plant pathogen capable of transferring a defined segment of DNA to a host plant, generating a gall tumor. Replacing the transferred tumor-inducing genes with exogenous DNA allows the introduction of any desired gene into the plant. Thus, A. tumefaciens has been critical for the development of modern plant genetics and agricultural biotechnology. Here we describe the genome of A. tumefaciens strain C58, which has an unusual structure consisting of one circular and one linear chromosome. We discuss genome architecture and evolution and additional genes potentially involved in virulence and metabolic parasitism of host plants. PMID:11743194

Goodner, B; Hinkle, G; Gattung, S; Miller, N; Blanchard, M; Qurollo, B; Goldman, B S; Cao, Y; Askenazi, M; Halling, C; Mullin, L; Houmiel, K; Gordon, J; Vaudin, M; Iartchouk, O; Epp, A; Liu, F; Wollam, C; Allinger, M; Doughty, D; Scott, C; Lappas, C; Markelz, B; Flanagan, C; Crowell, C; Gurson, J; Lomo, C; Sear, C; Strub, G; Cielo, C; Slater, S

2001-12-14

373

Zinc and copper in animal feed – development of resistance and co-resistance to antimicrobial agents in bacteria of animal origin  

PubMed Central

Farmed animals such as pig and poultry receive additional Zn and Cu in their diets due to supplementing elements in compound feed as well as medical remedies. Enteral bacteria in farmed animals are shown to develop resistance to trace elements such as Zn and Cu. Resistance to Zn is often linked with resistance to methicillin in staphylococci, and Zn supplementation to animal feed may increase the proportion of multiresistant E. coli in the gut. Resistance to Cu in bacteria, in particular enterococci, is often associated with resistance to antimicrobial drugs like macrolides and glycopeptides (e.g. vancomycin). Such resistant bacteria may be transferred from the food-producing animals to humans (farmers, veterinarians, and consumers). Data on dose-response relation for Zn/Cu exposure and resistance are lacking; however, it seems more likely that a resistance-driven effect occurs at high trace element exposure than at more basal exposure levels. There is also lack of data which could demonstrate whether Zn/Cu-resistant bacteria may acquire antibiotic resistance genes/become antibiotics resistant, or if antibiotics-resistant bacteria are more capable to become Zn/Cu resistant than antibiotics-susceptible bacteria. Further research is needed to elucidate the link between Zn/Cu and antibiotic resistance in bacteria. PMID:25317117

Yazdankhah, Siamak; Rudi, Knut; Bernhoft, Aksel

2014-01-01

374

Simultaneous detection and quantification of select nitromusks, antimicrobial agent, and antihistamine in fish of grocery stores by gas chromatography-mass spectrometry.  

PubMed

Continually detected biologically persistent nitromusks; galaxolide (HHCB), tonalide (AHTN) and musk ketone (MK), antimicrobial triclosan (TCS), and antihistamine diphenhydramine (DPH) were examined for the first time in edible fillets originating from eight fish species grown in salt- and fresh-water. The sampled fish collected from local grocery stores were homogenized, extracted, pre-concentrated and analyzed by gas chromatography-mass spectrometry (GC-MS) using selected ion monitoring (SIM). The presence of the target compounds in fish extracts was confirmed based on similar mass spectral features and retention behavior with standards. Internal standard based calibration plots were used for quantification. The HHCB, AHTN, TCS and DPH were consistently observed with concentration of 0.163-0.892, 0.068-0.904, 0.189-1.182, and 0.942-7.472 ng g(-1), respectively. These values are at least 1-3 orders of magnitude lower than those obtained in environmental fish specimens. The MK was not detected in any fish. PMID:24377446

Foltz, James; Abdul Mottaleb, M; Meziani, Mohammed J; Rafiq Islam, M

2014-07-01

375

Zinc and copper in animal feed - development of resistance and co-resistance to antimicrobial agents in bacteria of animal origin.  

PubMed

Farmed animals such as pig and poultry receive additional Zn and Cu in their diets due to supplementing elements in compound feed as well as medical remedies. Enteral bacteria in farmed animals are shown to develop resistance to trace elements such as Zn and Cu. Resistance to Zn is often linked with resistance to methicillin in staphylococci, and Zn supplementation to animal feed may increase the proportion of multiresistant E. coli in the gut. Resistance to Cu in bacteria, in particular enterococci, is often associated with resistance to antimicrobial drugs like macrolides and glycopeptides (e.g. vancomycin). Such resistant bacteria may be transferred from the food-producing animals to humans (farmers, veterinarians, and consumers). Data on dose-response relation for Zn/Cu exposure and resistance are lacking; however, it seems more likely that a resistance-driven effect occurs at high trace element exposure than at more basal exposure levels. There is also lack of data which could demonstrate whether Zn/Cu-resistant bacteria may acquire antibiotic resistance genes/become antibiotics resistant, or if antibiotics-resistant bacteria are more capable to become Zn/Cu resistant than antibiotics-susceptible bacteria. Further research is needed to elucidate the link between Zn/Cu and antibiotic resistance in bacteria. PMID:25317117

Yazdankhah, Siamak; Rudi, Knut; Bernhoft, Aksel

2014-01-01

376

Antimicrobial peptides from scorpion venoms.  

PubMed

The need for new antimicrobial agents is becoming one of the most urgent requirements in modern medicine. The venoms of many different species are rich sources of biologically active components and various therapeutic agents have been characterized including antimicrobial peptides (AMPs). Due to their potent activity, low resistance rates and unique mode of action, AMPs have recently received much attention. This review focuses on AMPs from the venoms of scorpions and examines all classes of AMPs found to date. It gives details of their biological activities with reference to peptide structure. The review examines the mechanism of action of AMPs and with this information, suggests possible mechanisms of action of less well characterised peptides. Finally, the review examines current and future trends of scorpion AMP research, by discussing recent successes obtained through proteomic and transcriptomic approaches. PMID:24951876

Harrison, Patrick L; Abdel-Rahman, Mohamed A; Miller, Keith; Strong, Peter N

2014-09-01

377

Antimicrobial Susceptibilities of Clinical Isolates of HACEK Organisms  

PubMed Central

The “HACEK” organisms are a group of fastidious Gram-negative bacteria that cause a variety of infections, including infective endocarditis. Antimicrobial susceptibility testing is not universally available, and therapy for these infections is often empirical. We report the antimicrobial susceptibilities of 70 clinical HACEK isolates to 18 antimicrobials. All isolates were susceptible to ceftriaxone and levofloxacin, indicating that these agents remain appropriate empirical choices for the treatment of infections with this group of organisms. PMID:23403420

Coburn, Bryan; Toye, Baldwin; Rawte, Prasad; Jamieson, Frances B.; Farrell, David J.

2013-01-01

378

The antimicrobial activity of Azadirachta indica, Mimusops elengi, Tinospora cardifolia, Ocimum sanctum and 2% chlorhexidine gluconate on common endodontic pathogens: An in vitro study  

PubMed Central

Objective: To check the antimicrobial activity of Azadirachta indica (Neem), Ocimum sanctum (Tulsi), Mimusops elelngi (Bakul), Tinospora cardifolia (Giloy) and Chlorhexidine Gluconate (CHX) on common endodontic pathogens like Streptococcus mutans, Enterococcus faecalis and staphylococcus aureus. Materials and Methods: The agar diffusion test was used to check the antimicrobial activity of the Methanolic extracts of the medicinal plants along with CHX. Six different concentrations of the tested agents were used for the study. The values of Zone of Inhibition were tabulated according to the concentration of the tested agent and data was statistically analyzed using ANOVA and Bonferroni post- hoc tests. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentrations (MBC) values were also recorded. Results: All the plants extracts showed considerable antimicrobial activity against selected endodontic pathogens. At 3mg. concentration, O.sanctum was the most effective against S. mutans, M. elengi showed highest zone of inhibition against E.faecalis, whereas CHX was the most effective agent against S.aureus. CHX was also the most consistent of all the medicaments testes, showing inhibitory effect against all the tree pathogens at all the selected concentrations. Conclusions: The Methanolic extract of A.Indica, O.sanctum, M. Elengi, T.cardifolia and Chlorhexidine Gluconate has considerable antimicrobial activity against S. mutans, E. faecalis and S. aureus. PMID:24966766

Mistry, Kunjal S.; Sanghvi, Zarna; Parmar, Girish; Shah, Samir

2014-01-01

379

Plant extracts, isolated phytochemicals, and plant-derived agents which are lethal to arthropod vectors of human tropical diseases--a review.  

PubMed

The recent scientific literature on plant-derived agents with potential or effective use in the control of the arthropod vectors of human tropical diseases is reviewed. Arthropod-borne tropical diseases include: amebiasis, Chagas disease (American trypanosomiasis), cholera, cryptosporidiosis, dengue (hemorrhagic fever), epidemic typhus (Brill-Zinsser disease), filariasis (elephantiasis), giardia (giardiasis), human African trypanosomiasis (sleeping sickness), isosporiasis, leishmaniasis, Lyme disease (lyme borreliosis), malaria, onchocerciasis, plague, recurrent fever, sarcocystosis, scabies (mites as causal agents), spotted fever, toxoplasmosis, West Nile fever, and yellow fever. Thus, coverage was given to work describing plant-derived extracts, essential oils (EOs), and isolated chemicals with toxic or noxious effects on filth bugs (mechanical vectors), such as common houseflies (Musca domestica Linnaeus), American and German cockroaches (Periplaneta americana Linnaeus, Blatella germanica Linnaeus), and oriental latrine/blowflies (Chrysomya megacephala Fabricius) as well as biting, blood-sucking arthropods such as blackflies (Simulium Latreille spp.), fleas (Xenopsylla cheopis Rothschild), kissing bugs (Rhodnius Stål spp., Triatoma infestans Klug), body and head lice (Pediculus humanus humanus Linnaeus, P. humanus capitis De Geer), mosquitoes (Aedes Meigen, Anopheles Meigen, Culex L., and Ochlerotatus Lynch Arribálzaga spp.), sandflies (Lutzomyia longipalpis Lutz & Neiva, Phlebotomus Loew spp.), scabies mites (Sarcoptes scabiei De Geer, S. scabiei var hominis, S. scabiei var canis, S. scabiei var suis), and ticks (Ixodes Latreille, Amblyomma Koch, Dermacentor Koch, and Rhipicephalus Koch spp.). Examples of plant extracts, EOs, and isolated chemicals exhibiting noxious or toxic activity comparable or superior to the synthetic control agents of choice (pyrethroids, organophosphorous compounds, etc.) are provided in the text for many arthropod vectors of tropical diseases. PMID:21432748

Pohlit, Adrian Martin; Rezende, Alex Ribeiro; Lopes Baldin, Edson Luiz; Lopes, Norberto Peporine; Neto, Valter Ferreira de Andrade

2011-04-01

380

Soils as agents of selection: feedbacks between plants and soils alter seedling survival and performance  

Microsoft Academic Search

Soils are one of the first selective environments a seed experiences and yet little is known about the evolutionary consequences\\u000a of plant-soil feedbacks. We have previously found that plant phytochemical traits in a model system, Populus spp., influence rates of leaf litter decay, soil microbial communities and rates of soil net nitrogen mineralization. Utilizing\\u000a this natural variation in plant-soil linkages

Clara C. PregitzerJoseph; Joseph K. Bailey; Stephen C. Hart; Jennifer A. Schweitzer

2010-01-01

381

Antifungal proteins: More than antimicrobials?  

PubMed Central

Antimicrobial proteins (AMPs) are widely distributed in nature. In higher eukaryotes, AMPs provide the host with an important defence mechanism against invading pathogens. AMPs of lower eukaryotes and prokaryotes may support successful competition for nutrients with other microorganisms of the same ecological niche. AMPs show a vast variety in structure, function, antimicrobial spectrum and mechanism of action. Most interestingly, there is growing evidence that AMPs also fulfil important biological functions other than antimicrobial activity. The present review focuses on the mechanistic function of small, cationic, cysteine-rich AMPs of mammals, insects, plants and fungi with antifungal activity and specifically aims at summarizing current knowledge concerning additional biological properties which opens novel aspects for their future use in medicine, agriculture and biotechnology. PMID:23412850

Hegedüs, Nikoletta; Marx, Florentine

2013-01-01

382

Phytochemical Screening and Antimicrobial Activity of Some Medicinal Plants Against Multi-drug Resistant Bacteria from Clinical Isolates  

PubMed Central

The in vitro antibacterial activity of various solvents and water extracts of aloe vera, neem, bryophyllum, lemongrass, tulsi, oregano, rosemary and thyme was assessed on 10 multi-drug resistant clinical isolates from both Gram-positive and Gram-negative bacteria and two standard strains including Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922. The zone of inhibition as determined by agar well diffusion method varied with the plant extract, the solvent used for extraction, and the organism tested. Klebsiella pneumoniae 2, Escherichia coli 3 and Staphylococcus aureus 3 were resistant to the plant extracts tested. Moreover, water extracts did not restrain the growth of any tested bacteria. Ethanol and methanol extracts were found to be more potent being capable of exerting significant inhibitory activities against majority of the bacteria investigated. Staphylococcus aureus 1 was the most inhibited bacterial isolate with 24 extracts (60%) inhibiting its growth whereas Escherichia coli 2 exhibited strong resistance being inhibited by only 11 extracts (28%). The results obtained in the agar diffusion plates were in fair correlation with that obtained in the minimum inhibitory concentration tests. The minimum inhibitory concentration of tulsi, oregano, rosemary and aloe vera extracts was found in the range of 1.56-6.25 mg/ml for the multi-drug resistant Staphylococcus aureus isolates tested whereas higher values (6.25-25 mg/ml) were obtained against the multi-drug resistant isolates Klebsiella pneumoniae 1 and Escherichia coli 1 and 2. Qualitative phytochemical analysis demonstrated the presence of tannins and saponins in all plants tested. Thin layer chromatography and bioautography agar overlay assay of ethanol extracts of neem, tulsi and aloe vera indicated flavonoids and tannins as major active compounds against methicillin-resistant Staphylococcus aureus. PMID:23716873

Dahiya, Praveen; Purkayastha, Sharmishtha

2012-01-01

383

Lost in translation: Differences in antimicrobial indication approval policies between the United States and Europe  

Microsoft Academic Search

Objective: Antimicrobials, like all drug products, are approved in the United States through the Food and Drug Administration (FDA) and in the European Union partly through the European Medicines Agency (EMEA). This article investigates the differences in approved indications between these 2 bodies for a series of antimicrobial agents approved during the past decade.Methods: The antimicrobial compounds most recently approved

Georgios Pappas; Vrettos Ierodiakonou; Matthew E. Falagas

2009-01-01

384

Comparison of antimicrobial activity of essential oils, plant extracts and methylparaben in cosmetic emulsions: 2 months study.  

PubMed

The aim of the study was to compare the preservative effectiveness of plant extracts (Matricaria chamomilla, Aloe vera, Calendula officinalis) and essential oils (Lavandulla officinalis, Melaleuca alternifolia, Cinnamomum zeylanicum) with methylparaben in cosmetic emulsions against skin microflora during 2 months of application by volunteers. Cosmetic emulsions with extracts (2.5 %), essential oils (2.5 %), methylparaben (0.4 %) or placebo were tested by 40 volunteers during 2 months of treatment. In order to determine microbial purity of the emulsions, the samples were taken after 0, 2, 4, 6 and 8 weeks of application. Throughout the trial period it was revealed that only cinnamon oil completely inhibited the growth of bacteria, yeast and mould, as compared to all other essential oils, plant extracts and methylparaben in the tested emulsions. This result shows that cinnamon oil could successfully replace the use of methylparaben in cosmetics, at the same time ensuring microbiological purity of a cosmetic product under its in-use and storage conditions. PMID:24891745

Herman, Anna

2014-09-01

385

Anti-microbial activity and anti-complement activity of extracts obtained from selected Hawaiian medicinal plants.  

PubMed

Selected plants having a history of use in Polynesian traditional medicine for the treatment of infectious disease were investigated for anti-viral, anti-fungal and anti-bacterial activity in vitro. Extracts from Scaevola sericea, Psychotria hawaiiensis, Pipturus albidus and Eugenia malaccensis showed selective anti-viral activity against Herpes Simplex Virus-1 and 2 and Vesicular Stomatitis Virus. Aleurites moluccana extracts showed anti-bacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa, while Pipturus albidus and Eugenia malaccensis extracts showed growth inhibition of Staphylococcus aureus and Streptococcus pyogenes. Psychotria hawaiiensis and Solanum niger inhibited growth of the fungi Microsporum canis, Trichophyton rubrum and Epidermophyton floccosum, while Ipomoea sp., Pipturus albidus, Scaevola sericea, Eugenia malaccensis, Piper methysticum, Barringtonia asiatica and Adansonia digitata extracts showed anti-fungal activity to a lesser extent. Eugenia malaccensis was also found to inhibit the classical pathway of complement suggesting that an immunological basis for its in vivo activity was identified. This study has confirmed some of the ethnobotanical reports of Hawaiian medicinal plants having curative properties against infections using biological assays in vitro. PMID:8786654

Locher, C P; Burch, M T; Mower, H F; Berestecky, J; Davis, H; Van Poel, B; Lasure, A; Vanden Berghe, D A; Vlietinck, A J

1995-11-17

386

Compatability of a Biological Control Agent with Herbicides for Control of Invasive Plant Species  

Technology Transfer Automated Retrieval System (TEKTRAN)

Kudzu, Pueraria montana var lobata, is an exotic invasive weed that is difficult to control with available products and management practices. The fungal pathogen, Myrothecium verrucaria, is being developed as a bioherbicide for kudzu and other invasive vines. This biological control agent might be...

387

Locust bean gum (LBG) as a gelling agent for plant tissue culture media  

Microsoft Academic Search

Locust bean gum (LBG) is a natural hydrocolloid extracted from the seeds of carob tree (Ceratonia siliqua L.). This work describes the successful use of LBG as a gelling agent in combination with agar for shoot multiplication and rooting of carob tree and Iberian rose shoots. Its presence did not affect the multiplication rate of both species. The rooting frequency

S. Gonçalves; A. Romano

2005-01-01

388

Host immune modulation by antimicrobial drugs: current knowledge and implications for antimicrobial chemotherapy.  

PubMed

It is known that antimicrobial agents possess several, beneficial, secondary properties which complement their primary antimicrobial activity like the immunomodulatory capacity that enforces host defense mechanisms or reduces host inflammatory response. In this review the current state of our recent research about the interaction between some antimicrobial agents and the immune system as complex pyramid of redundant cellular factors, humoral effectors and mediators against various microbial pathogens, will be presented and compared with recent literature data. The nature of such interactions is diverse and depends on the drug, the host immunological status and the microorganism. A more complete understanding of the host immune modulation by antimicrobial drugs may guide the selection of appropriate regimens for given clinical situations. PMID:25201570

Banche, Giuliana; Allizond, Valeria; Mandras, Narcisa; Tullio, Vivian; Cuffini, Anna Maria

2014-10-01

389

Richard Bradley: a unified, living agent theory of the cause of infectious diseases of plants, animals, and humans in the first decades of the 18th century.  

PubMed

During the years 1714 to 1721, Richard Bradley, who was later to become the first Professor of Botany at Cambridge University, proposed a unified, unique, living agent theory of the cause of infectious diseases of plants and animals and the plague of humans. Bradley's agents included microscopic organisms, revealed by the studies of Robert Hooke and Antony van Leeuwenhoek. His theory derived from his experimental studies of plants and their diseases and from microscopic observation of animalcules in different naturally occurring and artificial environments. He concluded that there was a microscopic world of "insects" that lived and reproduced under the appropriate conditions, and that infectious diseases of plants were caused by such "insects." Since there are structural and functional similarities between plants and animals, Bradley concluded that microscopic organisms caused human and animal infectious diseases as well. However, his living agent cause of infectious diseases was not accepted by the contemporary scientific society. PMID:19855125

Santer, Melvin

2009-01-01

390

Antimicrobial activity of sesquiterpene lactones isolated from traditional medicinal plant, Costus speciosus (Koen ex.Retz.) Sm  

PubMed Central

Background Costus speciosus (Koen ex.Retz.) Sm (Costaceae) is an Indian ornamental plant which has long been used medicinally in traditional systems of medicine. The plant has been found to possess diverse pharmacological activities. Rhizomes are used to treat pneumonia, rheumatism, dropsy, urinary diseases, jaundice, skin diseases and leaves are usedto treat mental disorders. Method Antibacterial and antifungal activities were tested using Disc diffusion method and Minimum Inhibitory Concentration (MIC). Column chromatography was used to isolate compounds from hexane extract. X-ray crystallography technique and GC-MS analysis were used to identify the compounds Results Antibacterial and antifungal activities were observed in hexane, chloroform, ethyl acetate and methanol extracts. Hexane extract of C.speciosus showed good activity against tested fungi also. Two sesquiterpenoid compounds were isolated (costunolide and eremanthin) from the hexane extract. Both the compounds did not inhibit the growth of tested bacteria. But, both the compounds inhibited the tested fungi. The compound costunolide showed significant antifungal activity. The MIC values of costunolide were; 62.5 ?g/ml against Trichophyton mentagrophytes, 62. ?g/ml against T. simii, 31.25 ?g/ml against T. rubrum 296, 62.5 ?g/ml against T. rubrum 57, 125 ?g/ml against Epidermophyton floccosum, 250 ?g/ml against Scopulariopsis sp, 250 ?g/ml against Aspergillus niger, 125 ?g/ml against Curvulari lunata, 250 ?g/ml against Magnaporthe grisea. Conclusion Hexane extract showed promising antibacterial and antifungal activity. The isolated compound costunolide showed good antifungal activity. PMID:22397713

2012-01-01

391

Acetohydroxyacid synthase: a target for antimicrobial drug discovery.  

PubMed

Acetohydroxyacid synthase (AHAS) (EC 2.2.1.6) (also known as acetolactate synthase) is the first common enzyme in the branched chain amino acid (BCAA) biosynthesis pathway. This pathway is present in microorganisms and in plants but not in animals, making it an attractive target for both drug and herbicide discovery. The function of AHAS is to catalyze the conversion of two molecules of pyruvate to 2-acetolactate or to convert one molecule of pyruvate and a molecule of 2-ketobutyrate into 2-aceto-2-hydroxybutyrate. Three cofactors are required for the activity of AHAS: thiamine diphosphate (ThDP), Mg²? and flavin-adenine dinucleotide (FAD). AHAS is the target for several classes of commercial herbicides that include the sulfonylurea and imidazolinone families. These herbicides are potent and selective inhibitors of AHAS with Ki values that can be in the low nM range. Such compounds also exhibit low application rates as herbicides (typically ~3 g ha?¹) and have low mammalian toxicity (LD?? values typically >4g/kg), thereby highlighting their utility and effectiveness as biocidal agents. However, somewhat surprisingly given the central importance of AHAS in the metabolism of microorganisms, no inhibitors of this enzyme have been commercialized into antimicrobial agents. Here we provide an overview of the biochemical characterization of AHASs from bacterial and fungal sources, analyse the structural features of these enzymes that are criticial to catalysis andprovide the current data on AHAS inhibitors that have potential to be developed into antimicrobial therapeutics. PMID:23688082

Pue, Nason; Guddat, Luke W

2014-01-01

392

The Potential of Thiarubrine C as a Nematicidal Agent against Plant- parasitic Nematodes.  

PubMed

Thiarubrine C, a polyacetylenic 1,2-dithiin isolated from the roots of Rudbeckia hirta (Asteraceae), exhibited strong nematicidal activity in in vitro and growth chamber assays. Thiarubrine C was toxic, in the absence of light, to the plant-parasitic nematodes Meloidogyne incognita and Pratylenchus penetrans at LCs of 12.4 ppm and 23.5 ppm, respectively. A minimum exposure time between 12 and 24 hours was the critical period for nematode mortality due to thiarubrine C. Although thiarubrine C was not totally dependent on light for toxicity, activity was enhanced in the presence of light, especially with the microbivorous nematode, Teratorhabditis dentifera. Upon exposure of M. incognita juveniles to 20 ppm thiarubrine C for 1 hour, infection of tomato plants was greatly reduced compared to untreated checks. Thiarubrine C was also effective in reducing plant infection when mixed with soil 24 hours prior to or at planting, unlike other related compounds such as delta-terthienyl. PMID:19274210

Sánchez Deviala, S; Brodie, B B; Rodriguez, E; Gibson, D M

1998-06-01

393

The Potential of Thiarubrine C as a Nematicidal Agent against Plant- parasitic Nematodes  

PubMed Central

Thiarubrine C, a polyacetylenic 1,2-dithiin isolated from the roots of Rudbeckia hirta (Asteraceae), exhibited strong nematicidal activity in in vitro and growth chamber assays. Thiarubrine C was toxic, in the absence of light, to the plant-parasitic nematodes Meloidogyne incognita and Pratylenchus penetrans at LC??s of 12.4 ppm and 23.5 ppm, respectively. A minimum exposure time between 12 and 24 hours was the critical period for nematode mortality due to thiarubrine C. Although thiarubrine C was not totally dependent on light for toxicity, activity was enhanced in the presence of light, especially with the microbivorous nematode, Teratorhabditis dentifera. Upon exposure of M. incognita juveniles to 20 ppm thiarubrine C for 1 hour, infection of tomato plants was greatly reduced compared to untreated checks. Thiarubrine C was also effective in reducing plant infection when mixed with soil 24 hours prior to or at planting, unlike other related compounds such as ?-terthienyl. PMID:19274210

Sánchez deViala, Susanna; Brodie, Bill B.; Rodriguez, Eloy; Gibson, Donna M.

1998-01-01

394

LAMP: A Database Linking Antimicrobial Peptides  

PubMed Central

The frequent emergence of drug-resistant bacteria has created an urgent demand for new antimicrobial agents. Traditional methods of novel antibiotic development are almost obsolete. Antimicrobial peptides (AMPs) are now regarded as a potential solution to revive the traditional methods of antibiotic development, although, until now, many AMPs have failed in clinical trials. A comprehensive database of AMPs with information about their antimicrobial activity and cytotoxicity will help promote the process of finding novel AMPs with improved antimicrobial activity and reduced cytotoxicity and eventually accelerate the speed of translating the discovery of new AMPs into clinical or preclinical trials. LAMP, a database linking AMPs, serves as a tool to aid the discovery and design of AMPs as new antimicrobial agents. The current version of LAMP has 5,547 entries, comprising 3,904 natural AMPs and 1,643 synthetic peptides. The database can be queried using either simply keywords or combinatorial conditions searches. Equipped with the detailed antimicrobial activity and cytotoxicity data, the cross-linking and top similar AMPs functions implemented in LAMP will help enhance our current understanding of AMPs and this may speed up the development of new AMPs for medical applications. LAMP is freely available at: http://biotechlab.fudan.edu.cn/database/lamp. PMID:23825543

Lu, Hairong; Li, Guodong; Huang, Qingshan

2013-01-01

395

Biotransformation of monoterpenoids and their antimicrobial activities.  

PubMed

Biotransformation is an economically and ecologically viable technology which has been used extensively to modify the structures of many classes of biologically active products. The discovery of novel antimicrobial metabolites from biotransformation is an important alternative to overcome the increasing levels of drug resistance by plant and human pathogens. Monoterpenes, the main constituents of essential oils, are known for their antimicrobial activities. In 2004, Farooq, Atta-Ur-Rahman and Choudhary published a review on fungal transformation of monoterpenes which covers papers published up to 2002. The present review not only updates the previous one but also discusses the antimicrobial activities (antibacterial, antifungal and antiviral) of biotransformed compounds. PMID:25442268

Bhatti, Haq Nawaz; Khan, Saleha Suleman; Khan, Ajmal; Rani, Mubeen; Ahmad, Viqar Uddin; Choudhary, Muhammad Iqbal

2014-10-15

396

Antibacterial activity of some medicinal plants grown in Jordan.  

PubMed

In the present study, we evaluated the antimicrobial activity of 16 Jordanian medicinal plant extracts against four reference bacteria; Staphylococcus aureus, Enterobacter faecalis, Escherichia coli, and Salmonella typhi. For that purpose, whole plants were extracted and antimicrobial susceptibility testing and minimum inhibitory concentration (MIC) were determined. Ethanolic extracts of most medicinal plants exerted a dose-dependent cytotoxiciy against different reference bacteria. Origanum syriaca, Varthemia iphionoides, Psidium guajava, Sarcopoterium spinosa plant extracts were most active against S. aureus (MIC; 70 ?g/mL), E. faecalis (MIC; 130 ?g/mL), E. coli (MIC; 153 ?g/mL), and S. typhi (MIC; 110 ?g/mL), respectively. Results indicate that medicinal plants grown in Jordan might be a valuable source of starting materials for the extraction and/or isolation of new antibacterial agents. PMID:23455195

Masadeh, Majed Mohammad; Alkofahi, Ahmad Suleiman; Tumah, Haitham Najeeb; Mhaidat, Nizar Mahmoud; Alzoubi, Karem Hasan

2013-03-01

397

Antibiotics and enzymes produced by the biocontrol agent Streptomyces violaceusniger YCED-9  

Microsoft Academic Search

Streptomyces violaceusniger   strain YCED-9 is an antifungal biocontrol agent antagonistic to many different classes of plant pathogenic fungi. We discovered\\u000a that strain YCED-9 produces three antimicrobial compounds with antifungal activity. These compounds were purified and identified,\\u000a and included: AFA (Anti-Fusarium Activity), a fungicidal complex of polyene-like compounds similar to guanidylfungin A and\\u000a active against most fungi except oomycetes; nigericin, a

S R Trejo-Estrada; A Paszczynski; D L Crawford

1998-01-01

398

Screening for candidate bacterial biocontrol agents against soilborne fungal plant pathogens  

Microsoft Academic Search

Over the years, many bacterial isolates have been evaluated as potential biocontrol agents against soilborne fungal phytopathogens.\\u000a However, few of them were ultimately successful after evaluation in field trials. One of the major reasons for this failure\\u000a is the lack of appropriate screening procedures to select the most suitable microorganisms for disease control in diverse\\u000a soil environments. For this reason,

Clara Pliego; Cayo Ramos; Antonio de Vicente; Francisco M. Cazorla

2011-01-01

399

Discovery of cancer preventive agents from natural products: From plants to prevention  

Microsoft Academic Search

Cancer chemoprevention has traditionally been defined as a dietary or therapeutic approach for the prevention, delay, or reversal\\u000a of carcinogenesis. We currently expand this definition to include nontoxic applications for patients with established disease.\\u000a In this context, efficacy can be achieved by selectively altering cell-cycle progression. In the quest for new cancer chemopreventive\\u000a agents, we have focused on the isolation

Rajendra G. Mehta; John M. Pezzuto

2002-01-01

400

Antimicrobial susceptibility of Bifidobacterium.  

PubMed

The susceptibility pattern of 459 strains of bifidobacteria, representing 15 species, to 16 antimicrobial agents was determined by the broth dilution method. The majority of the strains derived from human faeces. Penicillin G, erythromycin, clindamycin, vancomycin and bacitracin were the most active compounds; they inhibited 90% of the strains at less than 1.6 micrograms/ml. All strains were susceptible to chloramphenicol (MIC90 = 2.0-5.8 micrograms/ml) and also to lincomycin (MIC50 = 0.64-1.5 micrograms/ml). Neomycin, streptomycin and tetracycline presented a great variability in their activity. Most strains were resistant to polymyxin B, nalidixic acid, kanamycin, gentamicin and metronidazole. The only variation in susceptibility which was observed among the different species concerned Bifidobacterium suis, which generally appeared to be more resistant than other species. PMID:6638754

Matteuzzi, D; Crociani, F; Brigidi, P

1983-01-01

401

Rosmarinic Acid and Its Methyl Ester as Antimicrobial Components of the Hydromethanolic Extract of Hyptis atrorubens Poit. (Lamiaceae)  

PubMed Central

Primary biological examination of four extracts of the leaves and stems of Hyptis atrorubens Poit. (Lamiaceae), a plant species used as an antimicrobial agent in Guadeloupe, allowed us to select the hydromethanolic extract of the stems for further studies. It was tested against 46 microorganisms in vitro. It was active against 29 microorganisms. The best antibacterial activity was found against bacteria, mostly Gram-positive ones. Bioautography enabled the isolation and identification of four antibacterial compounds from this plant: rosmarinic acid, methyl rosmarinate, isoquercetin, and hyperoside. The MIC and MBC values of these compounds and their combinations were determined against eight pathogenic bacteria. The best inhibitory and bactericidal activity was found for methyl rosmarinate (0.3?mg/mL). Nevertheless, the bactericidal power of rosmarinic acid was much faster in the time kill study. Synergistic effects were found when combining the active compounds. Finally, the inhibitory effects of the compounds were evaluated on the bacterial growth phases at two different temperatures. Our study demonstrated for the first time antimicrobial activity of Hyptis atrorubens with identification of the active compounds. It supports its traditional use in French West Indies. Although its active compounds need to be further evaluated in vivo, this work emphasizes plants as potent sources of new antimicrobial agents when resistance to antibiotics increases dramatically. PMID:24348709

Abedini, Amin; Roumy, Vincent; Mahieux, Séverine; Biabiany, Murielle; Standaert-Vitse, Annie; Rivière, Céline; Sahpaz, Sevser; Bailleul, François

2013-01-01

402

Antimicrobial silver: An unprecedented anion effect  

NASA Astrophysics Data System (ADS)

Silver is an indispensable metal but its use has to be minimised for sustainable growth. Much of the silver lost during use is unrecoverable; an example being its use as an antimicrobial agent, a property known since ages. While developing methods to create an affordable drinking water purifier especially for the developing world, we discovered that 50 parts per billion (ppb) of Ag+ released continuously from silver nanoparticles confined in nanoscale cages is enough to cause antimicrobial activity in conditions of normal water. Here we show that the antibacterial and antiviral activities of Ag+ can be enhanced ~1,000 fold, selectively, in presence of carbonate ions whose concentration was maintained below the drinking water norms. The protective layers of the organisms were affected during the carbonate-assisted antimicrobial activity. It is estimated that ~1,300 tons of silver can be saved annually using this new way to enhance its antimicrobial activity.

Swathy, J. R.; Sankar, M. Udhaya; Chaudhary, Amrita; Aigal, Sahaja; Anshup; Pradeep, T.

2014-11-01

403

Antimicrobial silver: An unprecedented anion effect  

PubMed Central

Silver is an indispensable metal but its use has to be minimised for sustainable growth. Much of the silver lost during use is unrecoverable; an example being its use as an antimicrobial agent, a property known since ages. While developing methods to create an affordable drinking water purifier especially for the developing world, we discovered that 50 parts per billion (ppb) of Ag+ released continuously from silver nanoparticles confined in nanoscale cages is enough to cause antimicrobial activity in conditions of normal water. Here we show that the antibacterial and antiviral activities of Ag+ can be enhanced ~1,000 fold, selectively, in presence of carbonate ions whose concentration was maintained below the drinking water norms. The protective layers of the organisms were affected during the carbonate-assisted antimicrobial activity. It is estimated that ~1,300 tons of silver can be saved annually using this new way to enhance its antimicrobial activity. PMID:25418185

Swathy, J. R.; Sankar, M. Udhaya; Chaudhary, Amrita; Aigal, Sahaja; Anshup; Pradeep, T.

2014-01-01

404

Antimicrobial-Coated Granules for Disinfecting Water  

NASA Technical Reports Server (NTRS)

Methods of preparing antimicrobialcoated granules for disinfecting flowing potable water have been developed. Like the methods reported in the immediately preceding article, these methods involve chemical preparation of substrate surfaces (in this case, the surfaces of granules) to enable attachment of antimicrobial molecules to the surfaces via covalent bonds. A variety of granular materials have been coated with a variety of antimicrobial agents that include antibiotics, bacteriocins, enzymes, bactericides, and fungicides. When employed in packed beds in flowing water, these antimicrobial-coated granules have been proven effective against gram-positive bacteria, gram-negative bacteria, fungi, and viruses. Composite beds, consisting of multiple layers containing different granular antimicrobial media, have proven particularly effective against a broad spectrum of microorganisms. These media have also proven effective in enhancing or potentiating the biocidal effects of in-line iodinated resins and of very low levels of dissolved elemental iodine.

Akse, James R.; Holtsnider, John T.; Kliestik, Helen

2011-01-01

405

Cytotoxic and antimicrobial activities of endophytic fungi isolated from Bacopa monnieri (L.) Pennell (Scrophulariaceae)  

PubMed Central

Background Endophytes, which reside in plant tissues, have the potential to produce novel metabolites with immense benefits for health industry. Cytotoxic and antimicrobial activities of endophytic fungi isolated from Bacopa monnieri (L.) Pennell were investigated. Methods Endophytic fungi were isolated from the Bacopa monnieri. Extracts from liquid cultures were tested for cytotoxicity against a number of cancer cell lines using the MTT assay. Antimicrobial activity was determined using the micro dilution method. Results 22% of the examined extracts showed potent (IC50 of <20 ?g/ml) cytotoxic activity against HCT-116 cell line. 5.5%, 11%, 11% of the extracts were found to be cytotoxic for MCF-7, PC-3, and A-549 cell lines respectively. 33% extracts displayed antimicrobial activity against at least one test organism with MIC value 10–100 ?g/ml. The isolate B9_Pink showed the most potent cytotoxic activity for all the cell lines examined and maximum antimicrobial activity against the four pathogens examined which was followed by B19. Conclusions Results indicated the potential for production of bioactive agents from endophytes of Bacopa monnieri. PMID:24512530

2014-01-01

406

Design and Engineering Strategies for Synthetic Antimicrobial Peptides  

NASA Astrophysics Data System (ADS)

Thousands of antimicrobial peptides (AMPs) of prokaryotic, fungal, plant, or animal origin have been identified, and their potential as lead compounds for the design of novel therapeutic agents in the treatment of infection, for stimulating the immune system, or in countering septic shock has been widely recognized. Added to this is their possible use in prophylaxis of infectious diseases for animal or plant protection, for disinfection of surgical instruments or industrial surfaces, and for food preservation among other commercially important applications. Since the early eighties, AMPs have been subject to a vast number of studies aimed at understanding what determines their potency and spectrum of activities against bacterial or fungal pathogens, and at maximizing these while limiting cytotoxic activities toward host cells. Much research has also been directed toward understanding specific mechanisms of action underlying the antimicrobial activity and selectivity, to be able to redesign the peptides for optimal performance. A central theme in the mode of action of many AMPs is their dynamic interaction with biological membranes, which involves various properties of these peptides such as, among others, surface hydrophobicity and polarity, charge, structure, and induced conformational variations. These features are often intimately interconnected so that engineering peptides to independently adjust any one property in particular is not an easy task. However, solid-phase peptide synthesis allows the use of a large repertoire of nonproteinogenic amino acids that can be used in the rational design of peptides to finely tune structural and physicochemical properties and precisely probe structure-function relationships.

Tossi, Alessandro

407

SECONDARY METABOLITES FROM PLANTS AND MARINE ORGANISMS AS SELECTIVE ANTI-CYANOBACTERIAL AGENTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Extracts of more than one thousand species of plants and marine organisms were evaluated for selective algicidal activity against the musty-odor cyanobacterium (blue-green alga) Oscillatoria perornata. Bioassay-guided fractionation yielded anti-cyanobacterial compounds from the tropical marine brow...

408

Siderophore as a potential plant growth-promoting agent produced by Pseudomonas aeruginosa JAS-25.  

PubMed

Siderophores scavenges Fe(+3) from the vicinity of the roots of plants, and thus limit the amount of iron required for the growth of pathogens such as Fusarium oxysporum, Pythium ultimum, and Fusarium udum, which cause wilt and root rot disease in crops. The ability of Pseudomonas to grow and to produce siderophore depends upon the iron content, pH, and temperature. Maximum yield of siderophore of 130 ?M was observed at pH 7.0 ± 0.2 and temperature of 30 °C at 30 h. The threshold level of iron was 50 ?M, which increases up to 150 ?M, favoring growth but drastically affecting the production of siderophore by Pseudomonas aeruginosa JAS-25. The seeds of agricultural crops like Cicer arietinum (chick pea), Cajanus cajan (pigeon pea), and Arachis hypogaea (ground nut) were treated with P. aeruginosa JAS-25, which enhanced the seed germination, root length, shoot length, and dry weight of chick pea, pigeon pea, and ground nut plants under pot studies. The efficient growth of the plants was not only due to the biocontrol activity of the siderophore produced by P. aeruginosa JAS-25 but also may be by the production of indole acetic acid (IAA), which influences the growth of the plants as phytohormones. PMID:25062779

Sulochana, M B; Jayachandra, S Y; Kumar, S Anil; Parameshwar, A B; Reddy, K Mohan; Dayanand, A

2014-09-01

409

Antimicrobial bioassay-guided fractionation of a methanol extract of Eupatorium triplinerve.  

PubMed

Abstract Context: Eupatorium triplinerve Vahl (Asteraceae), popularly known as Japana, is widely used in folk medicine, due its analgesic, anticoagulant, antianorexic, antiparasitic, anthelmintic, sedative, antifungal, and antibacterial properties. Objective: The present study evaluated the chemical composition and antimicrobial activity of E. triplinerve extracts from different parts of the plant and identified the extract with the highest antimicrobial potential. Materials and methods: Extracts were obtained by maceration of all parts of plant, and subjected to bioassay-guided fractionation of methanol extract by partition column chromatography. The major chemical groups, saponins, reducing sugars, alkaloids, steroids, triterpenoids, phenols, tannins, flavonoids, and others were screened by standard techniques. The antimicrobial activity of the different extracts was performed by microdilution assay and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values were reported. Results: Phytochemical screening of hydroalcoholic extract from all parts of E. triplinerve identified mainly steroids, coumarins, alkaloids, saponins, tannins, depsides and absence of polysaccharides and flavonoids. The methanol extract of leaves presented the highest content of coumarins and lower MIC values of 62 and 75?µg/mL against Enterococcus faecalis and Staphylococcus aureus, respectively. In addition, its non-polar fractions showed antimicrobial activity with MIC ranging from 16 to 125?µg/mL against Gram-negative bacteria, mainly Escherichia coli. Discussion and conclusion: Data showed that non-polar fractions of E. triplinerve methanolic extract has better antimicrobial activity and most likely depends on the presence of several compounds, such as depsidones, coumarins, saponins, and triterpenes on crude extract. The results can be exploited largely in research of new antibacterial agents. PMID:25430540

Matos Lopes, Tamyris Regina; de Oliveira, Fábio Rodrigues; Malheiros, Flávia Filocreão; de Andrade, Marcieni Ataíde; Monteiro, Marta Chagas; Baetas Gonçalves, Ana Cristina

2014-11-28

410

Chemical analysis of plasma-assisted antimicrobial treatment on cotton  

NASA Astrophysics Data System (ADS)

This paper explores the use of plasma treatment as a pretreatment process to assist the application of antimicrobial process on cotton fabric with good functional effect. In this paper, antimicrobial finishing agent, Microfresh Liquid Formulation 9200-200 (MF), and a binder (polyurethane dispersion, Microban Liquid Formulation R10800-0, MB) will be used for treating the cotton fabric for improving the antimicrobial property and pre-treatment of cotton fabric by plasma under atmospheric pressure will be employed to improve loading of chemical agents. The chemical analysis of the treated cotton fabric will be conducted by Fourier transform Infrared Spectroscopy.

Kan, C. W.; Lam, Y. L.; Yuen, C. W. M.; Luximon, A.; Lau, K. W.; Chen, K. S.

2013-06-01

411

Using antimicrobial adjuvant therapy in cancer treatment: a review  

PubMed Central

Recent clinical and pre-clinical data demonstrate that adjuvant antimicrobial therapy is beneficial in cancer treatment. There could be several reasons for this effect, which include treating cancer associated bacteria and viruses, prophylaxis of post-chemotherapy infections due to immunosuppression, and antiproliferative effect of certain antimicrobials. Targeting cancer associated viruses and bacteria with antimicrobial agents is currently used for gastric, cervical, hematopoietic, liver and brain cancer. However this treatment is effective only in combination with conventional therapies. Antimicrobials can also have a direct antiproliferative and cytotoxic effect, and can cause apoptosis. Moreover, some antimicrobials are known to be helpful in overcoming side effects of drugs commonly used in cancer treatment. Chemotherapy related bacteremia and neutropenia can be overcome by the appropriately timed use of antimicrobials. This review summarizes the data on the effects of antivirals and antibiotics on cancer treatment and describes their mechanisms. PMID:23164412

2012-01-01

412

Agar and broth dilution methods to determine the minimal inhibitory concentration (MIC) of antimicrobial substances  

Microsoft Academic Search

The aim of broth and agar dilution methods is to determine the lowest concentration of the assayed antimicrobial agent (minimal inhibitory concentration, MIC) that, under defined test conditions, inhibits the visible growth of the bacterium being investigated. MIC values are used to determine susceptibilities of bacteria to drugs and also to evaluate the activity of new antimicrobial agents. Agar dilution

Irith Wiegand; Kai Hilpert; Robert E W Hancock

2008-01-01

413

Original article Antimicrobial activity of fatty acids  

E-print Network

Original article Antimicrobial activity of fatty acids against Bacillus larvae, the causative agent and unsaturated free fatty acids were tested for their antibiotic activ- ity against Bacillus larvae by the addition of one or more double bonds. The antibiotic activity of fatty acids may make them suitable for use

Paris-Sud XI, Université de

414

Antimicrobial Drugs  

PubMed Central

Antibiotics play a vital role in dental practice for managing orofacial infections. They are used to manage existing infection and they are also used as prophylaxis for certain medical conditions and surgical procedures. This article will review pharmacological and therapeutic considerations for the proper use of these agents for dental infections. PMID:24010989

Becker, Daniel E.

2013-01-01

415

Enhancing Agent Intelligence through Data Mining: A Power Plant Case Study  

NASA Astrophysics Data System (ADS)

In this paper, the methodology for an intelligent assistant for power plants is presented. Multiagent systems technology and data mining techniques are combined to enhance the intelligence of the proposed application, mainly in two aspects: increase the reliability of input data (sensor validation and false measurement replacement) and generate new control monitoring rules. Various classification algorithms are compared. The performance of the application, as tested via simulation experiments, is discussed.

Athanasopoulou, Christina; Chatziathanasiou, Vasilis

416

Plant Mounds as Concentration and Stabilization Agents for Actinide Soil Contaminants in Nevada  

SciTech Connect

Plant mounds or blow-sand mounds are accumulations of soil particles and plant debris around the base of shrubs and are common features in deserts in the southwestern United States. An important factor in their formation is that shrubs create surface roughness that causes wind-suspended particles to be deposited and resist further suspension. Shrub mounds occur in some plant communities on the Nevada Test Site, the Nevada Test and Training Range (NTTR), and Tonopah Test Range (TTR), including areas of surface soil contamination from past nuclear testing. In the 1970s as part of early studies to understand properties of actinides in the environment, the Nevada Applied Ecology Group (NAEG) examined the accumulation of isotopes of Pu, 241Am, and U in plant mounds at safety experiment and storage-transportation test sites of nuclear devices. Although aerial concentrations of these contaminants were highest in the intershrub or desert pavement areas, the concentration in mounds were higher than in equal volumes of intershrub or desert pavement soil. The NAEG studies found the ratio of contaminant concentration of actinides in soil to be greater (1.6 to 2.0) in shrub mounds than in the surrounding areas of desert pavement. At Project 57 on the NTTR, 17 percent of the area was covered in mounds while at Clean Slate III on the TTR, 32 percent of the area was covered in mounds. If equivalent volumes of contaminated soil were compared between mounds and desert pavement areas at these sites, then the former might contain as much as 34 and 62 percent of the contaminant inventory, respectively. Not accounting for radionuclides associated with shrub mounds would cause the inventory of contaminants and potential exposure to be underestimated. In addition, preservation of shrub mounds could be important part of long-term stewardship if these sites are closed by fencing and posting with administrative controls.

D.S. Shafer; J. Gommes

2009-02-03

417

Enhancing Agent Intelligence through Data Mining: A Power Plant Case Study  

Microsoft Academic Search

In this paper, the methodology for an intelligent assistant for power plants is presented. Multiagent systems technology and\\u000a data mining techniques are combined to enhance the intelligence of the proposed application, mainly in two aspects: increase\\u000a the reliability of input data (sensor validation and false measurement replacement) and generate new control monitoring rules.\\u000a Various classification algorithms are compared. The performance

Christina Athanasopoulou; Vasilis Chatziathanasiou

2009-01-01

418

Effects of feeding plant-derived agents on the colonization of Campylobacter jejuni in broiler chickens.  

PubMed

The aim of this work was to test the potential use of plant-derived extracts and compounds to control Campylobacter jejuni in broiler chickens. Over a 7-wk feeding period, birds were fed a commercial diet with or without plant extracts (Acacia decurrens, Eremophila glabra), essential oil [lemon myrtle oil (LMO)], plant secondary compounds [terpinene-4-ol and ?-tops (including ?-terpineol, cineole, and terpinene-4-ol)], and the antibiotic virginiamycin. Traditional culture and real-time quantitative PCR techniques were used to enumerate the numbers of C. jejuni in chicken fecal and cecal samples. In addition, BW and feed intake were recorded weekly for the calculation of BW gain and feed conversion ratio. The mean log10 counts of C. jejuni were similar (P > 0.05) across treatments. However, significantly lower levels of fecal Campylobacter counts (P < 0.05) were recorded at d 41 for the ?-tops treatment by culture methods. No differences (P > 0.05) in BW gain were obtained for dietary supplementation, except for