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1

Plant Products as Antimicrobial Agents  

PubMed Central

The use of and search for drugs and dietary supplements derived from plants have accelerated in recent years. Ethnopharmacologists, botanists, microbiologists, and natural-products chemists are combing the Earth for phytochemicals and “leads” which could be developed for treatment of infectious diseases. While 25 to 50% of current pharmaceuticals are derived from plants, none are used as antimicrobials. Traditional healers have long used plants to prevent or cure infectious conditions; Western medicine is trying to duplicate their successes. Plants are rich in a wide variety of secondary metabolites, such as tannins, terpenoids, alkaloids, and flavonoids, which have been found in vitro to have antimicrobial properties. This review attempts to summarize the current status of botanical screening efforts, as well as in vivo studies of their effectiveness and toxicity. The structure and antimicrobial properties of phytochemicals are also addressed. Since many of these compounds are currently available as unregulated botanical preparations and their use by the public is increasing rapidly, clinicians need to consider the consequences of patients self-medicating with these preparations. PMID:10515903

Cowan, Marjorie Murphy

1999-01-01

2

Plant Antimicrobial Agents and Their Effects on Plant and Human Pathogens  

PubMed Central

To protect themselves, plants accumulate an armoury of antimicrobial secondary metabolites. Some metabolites represent constitutive chemical barriers to microbial attack (phytoanticipins) and others inducible antimicrobials (phytoalexins). They are extensively studied as promising plant and human disease-controlling agents. This review discusses the bioactivity of several phytoalexins and phytoanticipins defending plants against fungal and bacterial aggressors and those with antibacterial activities against pathogens affecting humans such as Pseudomonas aeruginosa and Staphylococcus aureus involved in respiratory infections of cystic fibrosis patients. The utility of plant products as “antibiotic potentiators” and “virulence attenuators” is also described as well as some biotechnological applications in phytoprotection. PMID:20111686

Gonzalez-Lamothe, Rocio; Mitchell, Gabriel; Gattuso, Mariza; Diarra, Moussa S.; Malouin, Francois; Bouarab, Kamal

2009-01-01

3

Anthocyanins as antimicrobial agents of natural plant origin.  

PubMed

Anthocyanins are particularly abundant in different fruits, especially in berries. The beneficial effects of these compounds for human health have been known from at least the 16th century. Despite the great number of papers devoted to the different biological effects exerted by anthocyanins only a limited number of studies is focused on the antimicrobial activity of these compounds. Anthocyanin content of berry fruits varies from 7.5 mg/100 mg fresh fruit in redcurrant (Ribes rubum) up to 460 mg/100 g fresh fruit in chokeberry (Aronia melanocarpa). After consumption, anthocyanins are intensively metabolized, mainly in the intestines and liver. Glucorination, methylation and sulfation are the most typical metabolic reactions. Antimicrobial activity of crude extracts of plant phenolic compounds against human pathogens has been intensively studied to characterize and develop new healthy food ingredients as well as medical and pharmaceutical products. However, there is very little information available about the antimicrobial activity of the pure anthocyanins. In the last part of this review we present the collection of papers describing the anthocyanin profiles of different fruits (mainly berries) and the antimicrobial properties of the identified compounds. Generally, anthocyanins are active against different microbes, however Gram-positive bacteria usually are more susceptible to the anthocyanin action than Gram-negative ones. Mechanisms underlying anthocyanin activity include both membrane and intracellular interactions of these compounds. Antimicrobial activity of berries and other anthocyanin-containing fruits is likely to be caused by multiple mechanisms and synergies because they contain various compounds including anthocyanins, weak organic acids, phenolic acids, and their mixtures of different chemical forms. Therefore, the antimicrobial effect of chemically complex compounds has to be critically analyzed. PMID:21366068

Cisowska, Agnieszka; Wojnicz, Dorota; Hendrich, Andrzej B

2011-01-01

4

Medicinal plants and antimicrobial activity  

Microsoft Academic Search

In the present paper, we analyze the past, present and future of medicinal plants, both as potential antimicrobial crude drugs as well as a source for natural compounds that act as new anti-infection agents. In the past few decades, the search for new anti-infection agents has occupied many research groups in the field of ethnopharmacology. When we reviewed the number

J. L. Ríos; M. C. Recio

2005-01-01

5

Use of antimicrobial agents in food processing systems.  

PubMed

This article reviews the patents showing the use of antimicrobial agents in processing plants to eliminate the growth of the microorganism that affects on the quality and safety of the end products. Several materials have unique antimicrobial effects, especially towards biofilms in the processing equipments. The selection of a proper antimicrobial agent is essential to obtain the best results in preserving foods. The antimicrobial agent must not be toxic, and many factors need to be considered in choosing the right antimicrobial agent. PMID:22316268

Abushelaibi, Aisha A; Al Shamsi, Mariam S; Afifi, Hanan S

2012-04-01

6

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

7

Proarrhythmic Potential of Antimicrobial Agents  

Microsoft Academic Search

Several antiarrhythmic and non-cardiovascular drug therapies including antimicrobial agents have been implicated as the causes\\u000a for QT interval prolongation, torsades de pointes (TdP) ventricular tachycardia and sudden cardiac death. Most of the drugs\\u000a that have been associated with the lengthening of the QT interval or development of TdP can also block the rapidly activating\\u000a component of the delayed rectifier potassium

J. Simkó; A. Csilek; J. Karászi; I. L?rincz

2008-01-01

8

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

PubMed Central

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

9

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

10

Symposium on antimicrobial agents. Metronidazole.  

PubMed

Metronidazole, a nitroimidazole derivative, is a unique antimicrobial agent that is active against both bacterial and parasitic organisms, although only the anaerobic members of these groups are susceptible. It has been used for the treatment of trichomoniasis for almost 30 years and is also effective in amebiasis and giardiasis. More recently, metronidazole has emerged as a principal agent for the treatment of anaerobic infections. It is highly effective against all species of anaerobes except certain non-spore-forming gram-positive bacilli and cocci and is the only agent rapidly bactericidal against the Bacteroides fragilis group. The hydroxy metabolite is 65% as effective as metronidazole and may play a major therapeutic role. Clinical studies have substantiated its efficacy for prophylaxis during elective colorectal surgical procedures and the treatment of deep abdominal sepsis (usually in combination with another agent such as an aminoglycoside). Metronidazole is the treatment of choice for bacterial vaginosis and seems to be as effective as vancomycin for treatment of Clostridium difficile-related diarrhea and colitis. Good blood levels are produced after both oral and intravenous administration, and side effects are infrequent and minimal. Metronidazole should not be taken during the first trimester of pregnancy because of concerns about mutagenicity. Tinidazole and ornidazole are recently developed nitroimidazole derivatives that have even greater antimicrobial activity than metronidazole. PMID:3312851

Rosenblatt, J E; Edson, R S

1987-11-01

11

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

12

[Safety profile of antimicrobial agents].  

PubMed

Many antibiotics have been developed and used for the treatment of infectious diseases. Although they have been known to have various adverse effects, most of the mechanisms remain still unknown. New quinolones are well known to induce convulsions and their convulsant activity enhanced by concurrent administration of anti-inflammatory drugs. Each new quinolone has an individual convulsant activity with individual drug-interaction with anti-inflammatory drugs. And enoxacin, lomefloxacin and gatifloxacin have been reported to decrease blood glucose levels in a dose-depend- ent manner, but ciprofloxacin and levofloxacin had no effect on the levels. It should be important to know the safety profile of antimicrobial agents before doctors administer these agents to the patients with infectious diseases. PMID:21963968

Hori, Seiji

2011-01-01

13

Antimicrobial Activities of the Essential Oils of Various Plants against Tomato Late Blight Disease Agent Phytophthora infestans  

Microsoft Academic Search

The aim of this study was to find an alternative to synthetic fungicides currently used in the control of devastating oomycete\\u000a pathogen Phytophthora infestans, causal agent of late blight disease of tomato. Antifungal activities of essential oils obtained from aerial parts of aromatic\\u000a plants such as oregano (Origanum syriacum var. bevanii), thyme (Thymbra spicata subsp. spicata), lavender (Lavandula stoechas subsp.

E. Mine Soylu; Soner Soylu; Sener Kurt

2006-01-01

14

Protease Inhibitors from Plants with Antimicrobial Activity  

PubMed Central

Antimicrobial proteins (peptides) are known to play important roles in the innate host defense mechanisms of most living organisms, including plants, insects, amphibians and mammals. They are also known to possess potent antibiotic activity against bacteria, fungi, and even certain viruses. Recently, the rapid emergence of microbial pathogens that are resistant to currently available antibiotics has triggered considerable interest in the isolation and investigation of the mode of action of antimicrobial proteins (peptides). Plants produce a variety of proteins (peptides) that are involved in the defense against pathogens and invading organisms, including ribosome-inactivating proteins, lectins, protease inhibitors and antifungal peptides (proteins). Specially, the protease inhibitors can inhibit aspartic, serine and cysteine proteinases. Increased levels of trypsin and chymotrypsin inhibitors correlated with the plants resistance to the pathogen. Usually, the purification of antimicrobial proteins (peptides) with protease inhibitor activity was accomplished by salt-extraction, ultrafiltration and C18 reverse phase chromatography, successfully. We discuss the relation between antimicrobial and anti-protease activity in this review. Protease inhibitors from plants potently inhibited the growth of a variety of pathogenic bacterial and fungal strains and are therefore excellent candidates for use as the lead compounds for the development of novel antimicrobial agents. PMID:19582234

Kim, Jin-Young; Park, Seong-Cheol; Hwang, Indeok; Cheong, Hyeonsook; Nah, Jae-Woon; Hahm, Kyung-Soo; Park, Yoonkyung

2009-01-01

15

Linezolid: an oxazolidinone antimicrobial agent  

Microsoft Academic Search

Background: Linezolid is the first oxazolidinone anti-infective agent marketed in the United States. It is indicated for the treatment of nosocomial pneumonia, complicated skin and skin-structure infections caused by methicillin-sensitive or methicillin-resistant Staphylococcus aureus and other susceptible organisms, and vancomycin-resistant Enterococcus faecium infections. It also is indicated for the treatment of uncomplicated skin and skin-structure infections caused by methicillin-sensitive S

Horatio B. Fung; Harold L. Kirschenbaum; Babatunde O. Ojofeitimi

2001-01-01

16

Mechanisms of biofilm resistance to antimicrobial agents  

Microsoft Academic Search

Biofilms are communities of microorganisms attached to a surface. It has become clear that biofilm-grown cells express properties distinct from planktonic cells, one of which is an increased resistance to antimicrobial agents. Recent work has indicated that slow growth and\\/or induction of an rpoS-mediated stress response could contribute to biocide resistance. The physical and\\/or chemical structure of exopolysaccharides or other

Thien-Fah C. Mah; George A. O'Toole

2001-01-01

17

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

18

Cotton fabric finished with ?-cyclodextrin: Inclusion ability toward antimicrobial agent.  

PubMed

?-Cyclodextrin was grafted onto cotton fabric through crosslinking with butane tetracarboxylic acid in presence of sodium hypophosphite monohydrate as a catalyst. This finished cotton fabric was loaded with the antimicrobial agent octenidine dihydrochloride. ?-Cyclodextrin-grafted cotton fabrics, both after loading with octenidine dihydrochloride or before loading (control) were characterized for their antimicrobial activity against two types of bacteria (Gram positive and Gram negative) and two types of fungi, using the Diffusion Disk Method. The antimicrobial cotton fabric was subjected to several washing cycles and the antimicrobial activity was measured after each washing cycle to examine the durability of this antimicrobial finishing against repeated washing. The measurements showed that the finished cotton fabrics retain reasonable deal of their antimicrobial activity, even after 20 washing cycles. This long-lasting antimicrobial activity is attributed to the hosting ability of the cavities present in cyclodextrin moieties, which host the antimicrobial agent molecules and release them gradually. PMID:24507318

Abdel-Halim, E S; Al-Deyab, Salem S; Alfaifi, Ali Y A

2014-02-15

19

Antimicrobial Activity of Indigenous Medicinal Plants Against Enterococcus  

E-print Network

Antimicrobial Activity of Indigenous Medicinal Plants Against Enterococcus faecalis By Daniel, temperate zone of Chile. The collected plants were then tested for antimicrobial activity in a laboratory. #12;Antimicrobial Activity of Indigenous Medicinal Plants Against Enterococcus faecalis Introduction

Firestone, Jeremy

20

Consumption of Antimicrobial Agents and Occurrence of Antimicrobial Resistance in Bacteria from Food Animals, Food and Humans in Denmark.  

National Technical Information Service (NTIS)

Contents: Consumption of antimicrobial agents and occurrence of antimicrobial resistance in bacteria from food animals, food and humans in Denmark; Consumption of antimicronials and occurrence of antimicrobial resistance in bacteria collected from broiler...

F. Bager, J. Boel, S. Andersen, T. L. Soerensen

1997-01-01

21

Quaternary ammonium N,N-dichloroamines as topical, antimicrobial agents.  

PubMed

A series of backbone modified and sulfonic acid replacement analogs of our topical, clinical candidate (iii) were synthesized. Their antimicrobial activities and aqueous stabilities at pH 4 and pH 7 were determined, and has led us to identify quaternary ammonium N,N-dichloroamines as a new class of topical antimicrobial agents. PMID:19362467

Francavilla, Charles; Low, Eddy; Nair, Satheesh; Kim, Bum; Shiau, Timothy P; Debabov, Dmitri; Celeri, Chris; Alvarez, Nichole; Houchin, Ashley; Xu, Ping; Najafi, Ron; Jain, Rakesh

2009-05-15

22

Combating microbial resistance to antimicrobial agents through dosing regimen optimization  

E-print Network

to antimicrobial agents has evolved to alarming proportions. To avert potentially catastrophic consequences in the fields of public health today" (Food and Drug Administration, 2006). To avert potentially catastrophic

Nikolaou, Michael

23

[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

24

Diphosphonium Ionic Liquids as Broad Spectrum Antimicrobial Agents  

PubMed Central

Purpose One of the most disturbing trends in recent years is the growth of resistant strains of bacteria with the simultaneous dearth of new antimicrobial agents. Thus, new antimicrobial agents for use on the ocular surface are needed. Methods We synthesized a variety of ionic liquid compounds, which possess two positively charged phosphonium groups separated by ten methylene units in a “bola” type configuration. We tested these compounds for antimicrobial activity versus a variety of ocular pathogens, as well as their cytoxicity in vitro in a corneal cell line and in vivo in mice. Results The ionic liquid Di-Hex C10 demonstrated broad in vitro antimicrobial activity at the low micromolar concentrations versus Gram-negative and Gram-positive organisms, including methicillin-resistant Staphylococcus aureus strains, as well as ocular fungal pathogens. Treatment with Di-Hex C10 resulted in bacterial killing in as little as 15 minutes in vitro. Di-Hex C10 showed little cytotoxicity at 1 ?M versus a corneal epithelial cell line or at 10 ?M in a mouse corneal wound model. We also show that this bis-phosphonium ionic liquid structure is key, as a comparable mono phosphonium ionic liquid is cytotoxic to both bacteria and corneal epithelial cells. Conclusions Here we report the first use of dicationic bis-phosphonium ionic liquids as antimicrobial agents. Our data suggest that diphosphonium ionic liquids may represent a new class of broad-spectrum antimicrobial agents for use on the ocular surface. PMID:22236790

O’Toole, George A.; Wathier, Michel; Zegans, Michael E.; Shanks, Robert M.Q.; Kowalski, Regis; Grinstaff, Mark W.

2011-01-01

25

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

26

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

27

Resistance to antimicrobial agents: a personal view.  

PubMed

Problems of antimicrobial drug resistance are presently serious, but not yet desperate. The principal areas of concern are two-fold: multiresistant opportunist bacteria that affect vulnerable patients in high dependency areas of hospitals (the most pressing problem for developed countries); and multidrug resistance among classic pathogens like Mycobacterium tuberculosis, Salmonella typhi, Shigella spp., Neisseria gonorrhoeae and Plasmodium falciparum (mainly, although not exclusively, a problem for developing countries). The first type can be contained to a large extent by good infection control practices and careful prescribing based on agreed policies of antimicrobial drug use. The input of infection control nurses and laboratory-based clinical microbiologists is crucial and these services deserve full support. The second type additionally requires coordinated action to regulate more effectively the manufacture, availability, promotion and use of antimicrobial drugs. In this case the input of governments, international agencies and pharmaceutical companies is essential. Prescription-only status for antimicrobial drugs used in man and animals should be the norm. The number of drugs available for the treatment of viral, fungal and parasitic infections is comparatively small and much less is known about resistance. More research in these areas would be welcome. Teaching good prescribing habits to medical students is presently haphazard and needs to be formalised. Surveillance needs to be improved. The second half of the 20th century has been a golden age of antibiotics, but the outlook is uncertain. If antimicrobial chemotherapy is to have a secure future, prescribers must learn to use these powerful tools with greater discretion and their use worldwide must be regulated effectively. PMID:9736155

Greenwood, D

1998-09-01

28

In vitro susceptibilities of Pseudomonas pseudomallei to 27 antimicrobial agents.  

PubMed Central

Clinical isolates of Pseudomonas pseudomallei isolated in Thailand from 1981 to 1989 were tested for their in vitro susceptibilities to 27 antimicrobial agents, including older and newer quinolones, broad-spectrum cephems, carbapenems, monobactams, penicillins, tetracyclines, chloramphenicol, rifamycin, sulfamethoxazole, trimethoprim, and fosfomycin. Tosufloxacin, meropenem, CS-533, and minocycline were active against P. pseudomallei at levels comparable to or even greater than those of antimicrobial agents tested in previous studies, such as ciprofloxacin, ceftazidime, imipenem, carumonam, and piperacillin. Drug-resistant P. pseudomallei was found in only 1% of the isolates. The drug-resistant P. pseudomallei isolates displayed a unique pattern of susceptibility to the above-listed drugs. PMID:2291671

Yamamoto, T; Naigowit, P; Dejsirilert, S; Chiewsilp, D; Kondo, E; Yokota, T; Kanai, K

1990-01-01

29

Mushrooms as Possible Antioxidant and Antimicrobial Agents  

PubMed Central

The aim of the study is to examine in-vitro antioxidant and antimicrobial activity of the acetonic and methanolic extracts of the mushrooms Boletus aestivalis, Boletus edulis and Leccinum carpini. Antioxidant activity was evaluated by using free radical scavenging activity and reducing power. In addition, total content of phenol and flavonoid in extracts were determined as pyrocatechol equivalent, and as rutin equivalent, respectively. As a result of the study acetonic extracts from Boletus edulis was more powerful antioxidant activity with IC50 value of 4.72 ?g/mL which was similar or greater than the standard antioxidants, ascorbic acid (IC50 = 4.22 ?g/mL), BHA (IC50 = 6.42 ?g/mL) and ?-tocopherol (IC50 = 62.43 ?g/mL). Moreover, the tested extracts had effective reducing power. A significant relationship between total phenolic and flavonoid contents and their antioxidative activities was significantly observed. The antimicrobial activity of each extract was estimated by determination of the minimum inhibitory concentration by using microdilution plate method against five species of bacteria and five species of fungi. Generally, the tested mushroom extracts had relatively strong antimicrobial activity against the tested microorganisms. The minimum inhibitory concentration for both extracts related to the tested bacteria and fungi were 1.25 - 10 mg/ mL. The present study shows that tested mushroom species demonstrated a strong antioxidant and antimicrobial activity. It suggests that mushroom may be used as good sources of natural antioxidants and for pharmaceutical purposes in treating of various deseases. PMID:24250542

Kosani?, Marijana; Rankovi?, Branislav; Daši?, Marko

2012-01-01

30

Using Silver Nanoparticles as an Antimicrobial Agent  

Microsoft Academic Search

\\u000a Antimicrobial and antifungal properties of silver nanoparticles, silver ions, acrylate paint and cotton fabric impregnated\\u000a with Ag nanoparticles were assessed against Escherichia coli (Gram-negative bacterium); Staphylococcus aureus and Bacillus subtilis (Gram-positive bacteria); Aspergillus niger, Aureobasidium pullulans and Penicillium phoeniceum (cosmopolitan saprotrophic fungi). The silver ions used in the bacterial susceptibility tests were released from pure silver\\u000a electrodes using a 12

R. R. Khaydarov; R. A. Khaydarov; S. Evgrafova; Y. Estrin

31

Ferula gummosa Fruits: An Aromatic Antimicrobial Agent  

Microsoft Academic Search

Ferula gummosa Boiss. (Apiaceae) fruit volatile oil was analyzed by GC\\/MS. Seventy-three components (96.89%) were identified, and the major components were ?-pinene (43.78%), ?-pinene (27.27%), and myrcene (3.37%). The antimicrobial activity of the oil was tested on three strains of Gram positive bacteria (Staphylococcus aureus, S. epidermis, and Bacillus subtilis), three strains of Gram negative bacteria (Escherichia coli, Salmonella typhi,

Y. Ghasemi; P. Faridi; I. Mehregan; A. Mohagheghzadeh

2005-01-01

32

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

33

Improvement in shelf-life and safety of perishable foods by plant essential oils and smoke antimicrobials  

Microsoft Academic Search

This review examines the potency of natural antimicrobial agents from plants, outlining the ranges of microbial susceptibility and factors affecting antimicrobial action. Methods used for estimation of inhibitory activity are evaluated and currently understood mechanisms of their action are described. The potential value of these agents as secondary preservatives is considered as well as the effectiveness and use of similar

Richard A. Holley; Dhaval Patel

2005-01-01

34

Resistance to Antimicrobial Agents in Lactobacilli Isolated from Caper Fermentations  

Microsoft Academic Search

A collection of lactobacilli comprising species of Lactobacillus plantarum (43 isolates), Lactobacillus brevis (9 isolates) and Lactobacillus fermentum (6 isolates) obtained from spontaneous fermentations of capers (the fruits of Capparis spinosa) were investigated for resistance to antimicrobial agents. All isolates were resistant to vancomycin and teicoplanin (MIC  > 16 ?g\\/ml). Resistance to ciprofloxacin (MIC  > 2 ?g\\/ml) was detected in

Rubén Pérez Pulido; Nabil Ben Omar; Rosario Lucas; Hikmate Abriouel; Magdalena Martínez Cańamero; Antonio Gálvez

2005-01-01

35

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

36

Susceptibilities of Yersinia pestis Strains to 12 Antimicrobial Agents  

PubMed Central

Ninety-two strains of Yersinia pestis recovered over a 21-year period were evaluated for susceptibility to traditional and newer antimicrobial agents. In vitro resistance was noted only against rifampin and imipenem (?20% of strains). The most active compounds (MIC at which 90% of the isolates tested are inhibited) against Y. pestis were cefixime, ceftriaxone, trimethoprim-sulfamethoxazole, and trovafloxacin. PMID:10858370

Wong, Jane D.; Barash, Jason R.; Sandfort, Rebecca F.; Janda, J. Michael

2000-01-01

37

Total phenolic content, antioxidant and antimicrobial activities of some medicinal plants.  

PubMed

Crude extracts from Inula aucherana, Fumaria officinalis, Crocus sativus, Vicum album, Tribulus terestris, Polygonatum multiflorum, Alkanna tinctoria and Taraxacum officinale were screened for their in vitro antioxidant and antimicrobial properties. Total phenolic content of extracts from these plants were also determined. beta-carotene bleaching assay and Folin-Ciocalteu reagent were used to determine total antioxidant activity and total phenols of plant extracts. Antimicrobial activity was determined by using disk diffusion assay. Antioxidant activity and total phenolic content varied among plants used and Viscum album and Crocus sativus had the highest antioxidant (82.23%) and total phenolic content (42.29 mgGAE/g DW), respectively. The methanol extracts from Vicum album and Alkanna tinctoria showed antimicrobial activity against 9 out of 32 microorganisms, however extract from Inula aucherana showed antimicrobial activity against 15 out of 32 microorganisms. The results provided evidence that the studied plant might indeed be potential sources of natural antioxidant and antimicrobial agents. PMID:19168430

Sengul, Memnune; Yildiz, Hilal; Gungor, Neva; Cetin, Bulent; Eser, Zeynep; Ercisli, Sezai

2009-01-01

38

Systemic anti-microbial agents used in periodontal therapy  

PubMed Central

Periodontitis is an infectious disease with marked inflammatory response, leading to destruction of underlying tissues. The aim of periodontal therapy is to eradicate the pathogens associated with the disease and attain periodontal health. This is achieved by non-surgical and surgical therapy; however, mechanical debridement and topical application of antiseptics may not be helpful in all cases. In such cases, adjunctive systemic antibiotic therapy remains the treatment of choice. It can reach micro-organisms at the base of the deep periodontal pockets and furcation areas via serum, and also affect organisms residing within gingival epithelium and connective tissue. Before advising any anti-microbial agent, it is necessary to have knowledge of that agent. The aim of this review article is to provide basic details of each systemic anti-microbial agent used in periodontal therapy. The points discussed are its mode of action, susceptible periodontal pathogens, dosage, its use in treatment of periodontal disease, and mechanism of bacterial resistance to each anti-microbial agent. It might be of some help while prescribing these drugs. PMID:23869120

Patil, Vishakha; Mali, Rohini; Mali, Amita

2013-01-01

39

Systemic anti-microbial agents used in periodontal therapy.  

PubMed

Periodontitis is an infectious disease with marked inflammatory response, leading to destruction of underlying tissues. The aim of periodontal therapy is to eradicate the pathogens associated with the disease and attain periodontal health. This is achieved by non-surgical and surgical therapy; however, mechanical debridement and topical application of antiseptics may not be helpful in all cases. In such cases, adjunctive systemic antibiotic therapy remains the treatment of choice. It can reach micro-organisms at the base of the deep periodontal pockets and furcation areas via serum, and also affect organisms residing within gingival epithelium and connective tissue. Before advising any anti-microbial agent, it is necessary to have knowledge of that agent. The aim of this review article is to provide basic details of each systemic anti-microbial agent used in periodontal therapy. The points discussed are its mode of action, susceptible periodontal pathogens, dosage, its use in treatment of periodontal disease, and mechanism of bacterial resistance to each anti-microbial agent. It might be of some help while prescribing these drugs. PMID:23869120

Patil, Vishakha; Mali, Rohini; Mali, Amita

2013-03-01

40

Novel isoquinoline derivatives as antimicrobial agents.  

PubMed

The wide variety of potent biological activities of natural and synthetic isoquinoline alkaloids encouraged us to develop novel antimicrobial isoquinoline compounds. We synthesized a variety of differently functionalized 1-pentyl-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolines (THIQs), including dihydroisoquinolinium salts (2 and 5), methyl pentanoate-THIQ (6), 1-pentanol-THIQ (7), ester derivatives (8-15) and carbamate derivatives (16-23). We employed classic intramolecular Bischler-Napieralski cyclodehydration to generate the isoquinoline core. All the structures were characterized by nuclear magnetic resonance and mass spectrometry. The bactericide and fungicide activities were evaluated for all the synthesized compounds and structure-activity relationships were established. Many compounds exhibited high and broad-range bactericidal activity. Fluorophenylpropanoate ester 13 and the halogenated phenyl- (17, 18) and phenethyl carbamates (21, 22) exerted the most remarkable bactericidal activity. However, few compounds displayed antifungal activity against most of the fungi tested. Among them, chlorinated derivatives like chlorobenzoate and chlorophenylpropanoate esters (10 and 14, respectively) and chlorophenethyl carbamate 22, exhibited the greatest antifungal activity. PMID:23601815

Galán, Abraham; Moreno, Laura; Párraga, Javier; Serrano, Ángel; Sanz, Ma Jesús; Cortes, Diego; Cabedo, Nuria

2013-06-01

41

In vitro antimicrobial activity of peroxide-based bleaching agents.  

PubMed

Antibacterial activity of 4 commercial bleaching agents (Day White, Colgate Platinum, Whiteness 10% and 16%) on 6 oral pathogens (Streptococcus mutans, Streptococcus sobrinus, Streptococcus sanguinis, Candida albicans, Lactobacillus casei, and Lactobacillus acidophilus) and Staphylococcus aureus were evaluated. A chlorhexidine solution was used as a positive control, while distilled water was the negative control. Bleaching agents and control materials were inserted in sterilized stainless-steel cylinders that were positioned under inoculated agar plate (n = 4). After incubation according to the appropriate period of time for each microorganism, the inhibition zones were measured. Data were analyzed by 2-way analysis of variance and Tukey test (a = 0.05). All bleaching agents and the chlorhexidine solution produced antibacterial inhibition zones. Antimicrobial activity was dependent on peroxide-based bleaching agents. For most microorganisms evaluated, bleaching agents produced inhibition zones similar to or larger than that observed for chlorhexidine. C albicans, L casei, and L acidophilus were the most resistant microorganisms. PMID:17625621

Napimoga, Marcelo Henrique; de Oliveira, Rogério; Reis, André Figueiredo; Gonçalves, Reginaldo Bruno; Giannini, Marcelo

2007-06-01

42

Peptidomimetics as a new generation of antimicrobial agents: current progress  

PubMed Central

Antibiotic resistance is an increasing public health concern around the world. Rapid increase in the emergence of multidrug-resistant bacteria has been the target of extensive research efforts to develop a novel class of antibiotics. Antimicrobial peptides (AMPs) are small cationic amphiphilic peptides, which play an important role in the defense against bacterial infections through disruption of their membranes. They have been regarded as a potential source of future antibiotics, owing to a remarkable set of advantageous properties such as broad-spectrum activity, and they do not readily induce drug-resistance. However, AMPs have some intrinsic drawbacks, such as susceptibility to enzymatic degradation, toxicity, and high production cost. Currently, a new class of AMPs termed “peptidomimetics” have been developed, which can mimic the bactericidal mechanism of AMPs, while being stable to enzymatic degradation and displaying potent activity against multidrug-resistant bacteria. This review will focus on current findings of antimicrobial peptidomimetics. The potential future directions in the development of more potent analogs of peptidomimetics as a new generation of antimicrobial agents are also presented. PMID:25210467

Mendez-Samperio, Patricia

2014-01-01

43

Resistance to antimicrobial agents in lactobacilli isolated from caper fermentations.  

PubMed

A collection of lactobacilli comprising species of Lactobacillus plantarum (43 isolates), Lactobacillus brevis (9 isolates) and Lactobacillus fermentum (6 isolates) obtained from spontaneous fermentations of capers (the fruits of Capparis spinosa) were investigated for resistance to antimicrobial agents. All isolates were resistant to vancomycin and teicoplanin (MIC > 16 microg/ml). Resistance to ciprofloxacin (MIC > 2 microg/ml) was detected in all isolates of L. brevis and L. fermentum as well as in most isolates of L. plantarum, whilst resistance to levofloxacin showed a much lower incidence. Among L. plantarum and L. brevis isolates, low levels of resistance to tetracycline and/or nitrofurantoin were detected. Higher resistance levels were also detected in some isolates. Resistance to penicillin and rifampicin were also detected among L. plantarum isolates. All isolates were sensitive to ampicillin, erythromycin, chloramphenicol, gentamicin, streptomycin, and quinupristin/dalfopristin. PMID:16284934

Pérez Pulido, Rubén; Omar, Nabil Ben; Lucas, Rosario; Abriouel, Hikmate; Martínez Cańamero, Magdalena; Gálvez, Antonio

2005-01-01

44

Influence of topically applied antimicrobial agents on muscular microcirculation.  

PubMed

Bacterial infections cause major complications in wound healing. Local antiseptics are used for daily wound care; however, their potential toxic effects on the vasculature have not yet been thoroughly investigated. The aim of this study was to assess the effects of antiseptics on microcirculation. Investigations were performed on a standardized cremaster muscle model on rats (n = 60). The arteriolar diameter and functional capillary density (FCD) were investigated using transillumination microscopy before and 60 and 120 minutes after application of each of the following antimicrobial agents: alcohol, hydrogen peroxide, imipenem, octenidine dihydrochloride, polyhexanide, and ethacridine lactate. Although polyhexanide caused a significant arteriolar dilatation (106.25 ± 3.23 vs. 88.54 ± 6.74 ?m [baseline value]) and increase of FCD compared with baseline value (12.65 ± 0.82 vs. 9.10 ± 0.50 n/0.22 mm), alcohol led to a significant decrease of both parameters (90.63 ± 10.80 vs. 52.09 ± 7.69 and 5.35 ± 0.54 vs. 1.68 ± 0.48) and was the only agent that caused arteriolar thrombosis. The FCD also increased significantly after treatment with hydrogen peroxide (10.55 ± 0.33 vs. 12.30 ± 0.48) and octenidine (6.82 ± 0.63 vs. 12.32 ± 0.63). However, no positive effect on arteriolar diameter could be found. Ethacridine lactate and imipenem did not impact either parameter. In addition to reducing bacteria, an antiseptic should be nontoxic, especially to the microcirculation. Polyhexanide seems to have a positive influence on vessel diameter and capillary density, whereas alcohol reduces both parameters. If the antimicrobial efficacy is comparable, the antiseptic with less toxic effects should be chosen, especially in critically perfused wounds. PMID:21407057

Goertz, Ole; Hirsch, Tobias; Ring, Andrej; Steinau, Hans U; Daigeler, Adrien; Lehnhardt, Marcus; Homann, Heinz H

2011-10-01

45

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

46

Antimicrobial screening of ethnobotanically important stem bark of medicinal plants  

PubMed Central

Background: The stem barks are the rich sources of tannins and other phenolic compounds. Tannins inhibited the growth of various fungi, yeast, bacteria and virus. Hence, ten stem barks of ethnomedicinally important plants were screened for antibacterial and antifungal activities against human pathogenic strains. Methods: Air-dried and powdered stem bark of each plant was extracted with 50% aqueous ethanol, lyophilized and the dried crude extracts were used for the screening against 11 bacteria and 8 fungi. Antibacterial and antifungal activities were performed according to microdilution methods by NCCLS. Results: The plants Prosopis chilensis, Pithecellobium dulce, Mangifera indica showed significant antibacterial and antifungal activities against Streptococcus pneumonia, Enterobacter aerogenes, Klebsiella pneumonia and Candida albicans with MIC of 0.08mg/ml. Pithecellobium dulce bark also showed significant antibacterial activity against Bacillus cereus. Conclusion: The bark of Pithecellobium dulce has more or less similar activity against the known antibiotic and may be considered as potent antimicrobial agent for various infectious diseases. PMID:21808577

Singh, Meenakshi; Khatoon, Sayyada; Singh, Shweta; Kumar, Vivek; Rawat, Ajay Kumar Singh; Mehrotra, Shanta

2010-01-01

47

ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, 0066-4804/00/$04.00 0  

E-print Network

ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, 0066-4804/00/$04.00 0 Apr. 2000, p. 1097­1099 Vol. 44, No. 4 components of negative- feedback loops gain effectiveness against mutant viruses that attenuate the drug

Endy, Drew

48

Antimicrobial peptides: agents of border protection for companion animals  

PubMed Central

Over the past 20 years, there have been significant inroads into understanding the roles of antimicrobial peptides in homeostatic functions and their involvement in disease pathogenesis. In addition to direct antimicrobial activity, these peptides participate in many cellular functions, including chemotaxis, wound healing, and even determination of canine coat colour. Various biologic and genetic approaches have helped to elucidate the role of antimicrobial peptide with respect innate immunity and host defense. Associations of antimicrobial peptides with various skin diseases, including psoriasis, rosacea and atopic dermatitis, have been documented in humans. In the longer term, therapeutic modulation of antimicrobial peptide expression may provide effective new treatments for disease. This review highlights current knowledge about antimicrobial peptides of the skin and circulating leukocytes, with particular focus on relevance to physiology and disease in companion animals. PMID:22409270

Leonard, Brian C.; Affolter, Verena K.; Bevins, Charles L.

2012-01-01

49

In vitro susceptibility of Bacillus spp. to selected antimicrobial agents.  

PubMed Central

Although often dismissed as contaminants when isolated from blood cultures, Bacillus spp. are increasingly recognized as capable of causing serious systemic infections. As part of a clinical-microbiological study, 89 strains of Bacillus spp. isolated from clinical blood cultures between 1981 and 1985 had their species determined and were tested for antimicrobial agent susceptibility to 18 antibiotics. Species of isolates were determined by the API 50CH and API 20E systems. Bacillus cereus (54 strains) was the most common species isolated, followed by B. megaterium (13 strains), B. polymyxa (5 strains), B. pumilus (4 strains), B. subtilis (4 strains), B. circulans (3 strains), B. amyloliquefaciens (2 strains), B. licheniformis (1 strain), and Bacillus spp. (3 strains). Microdilution MIC susceptibility tests revealed all B. cereus strains to be susceptible to imipenem, vancomycin, chloramphenicol, gentamicin, and ciprofloxacin. Non-B. cereus strains were most susceptible to imipenem, vancomycin, LY146032, and ciprofloxacin. Disk susceptibility testing suggested that B. cereus was rarely susceptible to penicillins, semisynthetic penicillins, or cephalosporins with the exception of mezlocillin. In contrast, many non-B. cereus strains were susceptible to penicillins, semisynthetic penicillins, and cephalosporins, but marked variability was noted among species. PMID:3395100

Weber, D J; Saviteer, S M; Rutala, W A; Thomann, C A

1988-01-01

50

Susceptibility of Anaerobic Bacteria to Ten Antimicrobial Agents  

PubMed Central

The susceptibility pattern of 265 anaerobic bacteria from clinical isolates to 10 antimicrobial agents was investigated by the agar dilution technique. Penicillin G, in a concentration of 16 ?g/ml, was active against most organisms, important exceptions being 12% of Bacteroides melaninogenicus and 24% of B. fragilis strains. The susceptibility of strains to ampicillin was similar to their susceptibility to penicillin G. Carbenicillin, at ?128 ?g/ml, inhibited all but a few strains. Cefamandole was less active than the penicillins; 82% of B. melaninogenicus, 32% of B. fragilis, and 75% of Fusobacterium strains were inhibited by ?16 ?g/ml. A trend towards tetracycline resistance was seen in many bacterial groups, especially Bacteroides, Fusobacterium, and Clostridium. All organisms were susceptible to chloramphenicol and clindamycin in concentrations of ?16 ?g/ml and ?4 ?g/ml, respectively. Erythromycin was less active than clindamycin against all strains tested. Metronidazole and tinidazole were active against most anaerobes, but resistance of a few strains in each group was encountered. The increased resistance of B. melaninogenicus strains to penicillin, and emergence of anaerobes resistant to >16 ?g of imidazole per ml may have therapeutic implications. PMID:708014

Appelbaum, Peter C.; Chatterton, Sheila A.

1978-01-01

51

IN VITRO AND IN VIVO STUDY OF AN ANTIMICROBIAL ACTIVITY DISPLAYED BY THE REDMOUTH DISEASE AGENT, YERSINIA RUCKERI  

E-print Network

IN VITRO AND IN VIVO STUDY OF AN ANTIMICROBIAL ACTIVITY DISPLAYED BY THE REDMOUTH DISEASE AGENT of an antimicrobial factor secretion by Y ruckeri. As it was not possible to detail in a short note all our attempts

Paris-Sud XI, Université de

52

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

53

Pharmacokinetics and the dosage regimen of antimicrobial agents  

E-print Network

of the drug, adjunctive therapy, etc (Powers et al, 1984a). HOST-PARASITE RELATIONSHIP In animals having, France) Summary― Some consider antimicrobial therapy an art rather than a science. The drug Antimicrobial therapy has been an impor- tant part of veterinary practice, worldwide, for more than 40 years

Paris-Sud XI, Université de

54

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

55

The dynamic observation of plasma concentration of antimicrobial agents during balanced ultrafiltration in vitro.  

PubMed

Routine perioperative intravenous antimicrobial agents are administered as surgical prophylaxis. However, whether balanced ultrafiltration during extracorporeal circulation has substantial effect on the concentration of antimicrobial agents remains unclear. The concentrations of antimicrobial agents in plasma and ultrafiltrate samples were measured in this pseudo-extracorporeal circulation model. Extracorporeal circulation consisted of cardiotomy reservoir, membrane oxygenator, and pediatric arterial line filter. A hemoconcentrator was placed between the arterial purge line and oxygenator venous reservoir. Fresh donor human whole blood was added into the circuit and mixed with Ringer's solution to obtain a final hematocrit of 24-28%. Two kinds of antimicrobial agents, cefotiam (320?mg) and cefmetazole (160?mg), were bolus added into the circuit. After 30?min of extracorporeal circulation, zero-balanced ultrafiltration was initiated and arterial line pressure was maintained at approximately 100?mm?Hg with a Hoffman clamp. The rate of ultrafiltration (12?mL/min) was controlled by ultrafiltrate outlet pressure. An identical volume of Plasmalyte A was dripped into the circuit to maintain stable hematocrit during 45?min of experiment. Plasma and ultrafiltrate samples were drawn every 5?min, and concentrations of antimicrobial agents (including cefotiam and cefmetazole) were measured with high performance liquid chromatography. Both antimicrobial agents were detected in ultrafiltrate, demonstrating hemoconcentration may remove antimicrobial agents. The concentrations of plasma antimicrobial agents decreased linearly with the increase of ultrafiltrate volume. At end of balanced ultrafiltration, the concentration of plasma cefotiam was 104.96?±?44.36?mg/L, which is about 44.38%?±?7.42% of the initial concentration (238.95?±?101.12?mg/L) (P?antimicrobial agents from plasma and has a prominent influence on plasma concentration of antimicrobial agent. The strategy of surgical prophylaxis should consider this unique technique during extracorporeal circulation. PMID:23865445

Fang, Yinghui; Guan, Yulong; Wan, Caihong; Fu, Zhida; Jiang, Juanjuan; Wu, Chunfu; Zhao, Ju; Sun, Peng; Long, Cun

2014-01-01

56

Antimicrobial activity of selected Iranian medicinal plants against a broad spectrum of pathogenic and drug multiresistant micro-organisms.  

PubMed

The antimicrobial activities of 44 methanolic extracts from different parts of Iranian indigenous plant species used in traditional medicines of Iran were tested against a panel of 35 pathogenic and multiresistant bacteria and 1 yeast. The antimicrobial efficacy was determined using Müller-Hinton agar in Petri dishes seeded by a multiple inoculator and minimal inhibition concentration (MIC) method. The 21 most active extracts (MIC < 0·3 mg ml(-1) for one or several micro-organisms) were submitted to a more refined measurement. The best antibacterial activity was obtained by 10 plants. Microdilution assays allowed to determinate the MIC and MBC of the 21 most active extracts. The lowest achieved MIC value was 78 ?g ml(-1), with 4 extracts. This work confirms the antimicrobial activity of assayed plants and suggests further examination to identify the chemical structure of their antimicrobial compounds. Significance and impact of the study: This study describes the antimicrobial screening of Iranian plant extracts chosen according to traditional practice against 36 microbial strains, from reference culture collections or recent clinical isolates, and enables to select 4 candidates for further chemical characterization and biological assessment: Dorema ammoniacum, Ferula assa-foetida, Ferulago contracta (seeds) and Perovskia abrotanoides (aerial parts). This may be useful in the development of potential antimicrobial agents, from easily harvested and highly sustainable plant parts. Moreover, the weak extent of cross-resistance between plant extracts and antibiotics warrants further research and may promote a strategy based on less potent but time-trained products. PMID:24888993

Abedini, A; Roumy, V; Mahieux, S; Gohari, A; Farimani, M M; Rivičre, C; Samaillie, J; Sahpaz, S; Bailleul, F; Neut, C; Hennebelle, T

2014-10-01

57

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

58

Uptake, Transport, and Delivery of Antimicrobial Agents by Human Polymorphonuclear Neutrophils  

Microsoft Academic Search

Polymorphonuclear neutrophils (PMN) are attracted to sites of infection. They have the potential to deliver antimicrobial agents to these sites if the agents enter the cells and do not alter migration. Penicillin G did not enter cells and was not transported by PMN. We found that azithromycin, ciprofloxacin, levofloxacin, moxi- floxacin, and telithromycin were concentrated in PMN and transported toward

Gerald L. Mandell; Elizabeth Coleman

2001-01-01

59

In vitro bactericidal activities of antimicrobial agents and morphologic changes on Prevotella bivia.  

PubMed

Prevotella bivia is common in pelvic inflammatory diseases. Parenteral antimicrobial agents have been widely used against those infections. We investigated the bactericidal activities of three cephalosporins, i.e. cefluprenam (CFLP), ceftazidime (CAZ) and cefotaxime (CTX) and of two other antimicrobial agents, i.e. clindamycin (CLDM) and imipenem (IPM) against P. bivia. We also investigated the in vitro morphological changes induced by these agents in P. bivia. Cephalosporins exhibited bactericidal activities against P. bivia and induced time- and concentration-dependent morphological changes in P. bivia (filamentation). CLDM and IPM also had bactericidal activities, but induced different morphologic alterations: formation of spheroblasts and lysis. These results confirm the fact that each antimicrobial agent has characteristic aspects. PMID:10473922

Mikamo, H; Sato, Y; Hayasaki, Y; Kawazoe, K; Izumi, K; Satoh, M; Kai, J; Tamaya, T

1999-01-01

60

Resistance of Escherichia coli and Enterococcus spp. to selected antimicrobial agents present in municipal wastewater.  

PubMed

In this study, the susceptibility to erythromycin (E) and to trimethoprim/sulfamethoxazole (SXT) among isolates of Enterococcus spp. and Escherichia coli was tested, respectively. Both fecal indicators were detected and isolated from raw (RW) and treated wastewater (TW) as well as from samples of activated sludge (AS) collected in a local wastewater treatment plant (WWTP). Biodiversity of bacterial community in AS was also monitored using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Additionally, distribution of sul1-3 genes conferring sulfonamide resistance was tested among SXT-resistant E. coli. Simultaneously, basic physicochemical parameters and concentrations of eight antimicrobial compounds (belonging to folate pathway inhibitors and macrolides class) were analyzed in RW and TW samples. Six of the selected antimicrobial agents, namely: erythromycin, clarithromycin, trimethoprim, roxithromycin, sulfamethoxazole, and N-acetyl-sulfamethoxazole were detected in the wastewater samples. Bacterial biodiversity of AS samples were comparable with no relevant differences. Among tested Enterococcus spp., E-resistant isolates constituted 41%. SXT resistance was less prevalent in E. coli with 11% of isolates. The genes conferring resistance to sulfonamides (sul1-3) were detected in SXT-resistant E. coli of wastewater origin with similar frequencies as in other environmental compartments, including clinical ones. PMID:24334834

Luczkiewicz, Aneta; Felis, Ewa; Ziembinska, Aleksandra; Gnida, Anna; Kotlarska, Ewa; Olanczuk-Neyman, Krystyna; Surmacz-Gorska, Joanna

2013-12-01

61

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

62

Impact of Lactobacillus acidophilus on the normal intestinal microflora after administration of two antimicrobial agents  

Microsoft Academic Search

Summary Twenty healthy volunteers participated in a comparative study concerning the influence ofLactobacillus acidophilus supplements on the normal intestinal microflora after the administration of two antimicrobial agents, enoxacin and clindamycin, respectively.L. acidophilus NCFB 1748 was given as a fermented milk product containing 5 × 108-2 × 109 CFU\\/ml to ten of the volunteers immediately after the administration of the antimicrobial

A. Lidbeck; C. Edlund; J. Ĺ. Gustafsson; L. Kager; C. E. Nora

1988-01-01

63

Antimicrobial resistance of fecal indicators in municipal wastewater treatment plant  

Microsoft Academic Search

Antimicrobial resistance of fecal coliforms (n = 153) and enterococci (n = 199) isolates was investigated in municipal wastewater treatment plant (WWTP) based on activated sludge system. The number of fecal indicators (in influent and effluent as well as in the aeration chamber and in return activated sludge mixture) was determined using selective media. Susceptibility of selected strains was tested against 19 (aminoglycosides, aztreonam,

A. ?uczkiewicz; K. Jankowska; S. Fudala-Ksi??ek; K. Ola?czuk-Neyman

2010-01-01

64

Screening of some Cuban medicinal plants for antimicrobial activity  

Microsoft Academic Search

The antimicrobial activities of 23 extracts of 12 Cuban plant species reported in traditional medicine were tested. The agar diffusion method was used to assess the activity against four bacteria and one yeast: Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. The results, evaluated as the diameter of the inhibition zone of microbial growth, showed that nine

M. J. Martínez; J. Betancourt; N. Alonso-González; A. Jauregui

1996-01-01

65

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

66

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

67

In vitro susceptibility of equine-obtained isolates of Corynebacterium pseudotuberculosis to gallium maltolate and 20 other antimicrobial agents.  

PubMed

This study's objective was to determine the in vitro antimicrobial activities of gallium maltolate (GaM) and 20 other antimicrobial agents against clinical equine isolates of Corynebacterium pseudotuberculosis. The growth of cultured isolates was not inhibited by any concentration of GaM. MIC data revealed susceptibility to commonly used antimicrobials. PMID:24829243

Norman, T E; Batista, M; Lawhon, S D; Zhang, S; Kuskie, K R; Swinford, A K; Bernstein, L R; Cohen, N D

2014-07-01

68

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

69

Antimicrobial activity of certain Indian medicinal plants used in folkloric medicine  

Microsoft Academic Search

Fifty medicinal plants belonging to 26 families were studied for their antimicrobial activity. Among 50 plants tested, 72% showed antimicrobial activity. About 22 plant extracts from 15 families exhibited activity against both Gram-positive and Gram-negative bacteria. Fourteen plants belonging to 11 families did not show activity against any of the bacteria tested. Only nine plant extracts showed antifungal activity. The

D. Srinivasan; Sangeetha Nathan; T. Suresh; P. Lakshmana Perumalsamy

2001-01-01

70

[Recommendations for selecting antimicrobial agents for in vitro susceptibility studies using automatic and semiautomatic systems].  

PubMed

The number of clinical microbiology laboratories that have incorporated automatic susceptibility testing devices has increased in recent years. The majority of these systems determine MIC values using microdilution panels or specific cards, with grouping into clinical categories (susceptible, intermediate or resistant) and incorporate expert systems to infer resistance mechanisms. This document presents the recommendations of a group of experts designated by Grupo de Estudio de los Mecanismos de Acción y Resistencia a los Antimicrobianos (GEMARA, Study group on mechanisms of action and resistance to antimicrobial agents) and Mesa Espańola de Normalización de la Sensibilidad y Resistencia a los Antimicrobianos (MENSURA, Spanish Group for Normalizing Antimicrobial Susceptibility and Antimicrobial Resistance), with the aim of including antimicrobial agents and selecting concentrations for the susceptibility testing panels of automatic systems. The following have been defined: various antimicrobial categories (A: must be included in the study panel; B: inclusion is recommended; and C: inclusion is secondary, but may facilitate interpretative reading of the antibiogram) and groups (0: not used in therapeutics but may facilitate the detection of resistance mechanisms; 1: must be studied and always reported; 2: must be studied and selectively reported; 3: must be studied and reported at a second level; and 4: should be studied in urinary tract pathogens isolated in urine and other specimens). Recommended antimicrobial concentrations are adapted from the breakpoints established by EUCAST, CLSI and MENSURA. This approach will lead to more accurate susceptibility testing results with better detection of resistance mechanisms, and allowing to reach the clinical goal of the antibiogram. PMID:17583653

Cantón, Rafael; Alós, Juan Ignacio; Baquero, Fernando; Calvo, Jorge; Campos, José; Castillo, Javier; Cercenado, Emilia; Domínguez, M Angeles; Lińares, Josefina; López-Cerezo, Lorena; Marco, Francesc; Mirelis, Beatriz; Morosini, María-Isabel; Navarro, Ferran; Oliver, Antonio; Pérez-Trallero, Emilio; Torres, Carmen; Martínez-Martínez, Luis

2007-01-01

71

Antimicrobial abilities of various dentine bonding agents and restorative materials  

Microsoft Academic Search

Objectives: The purpose of this study was to observe and measure the in vitro effect of various composite restorative materials and dentine bonding agents on the growth and adherence of oral bacteria believed to be responsible for recurrent caries in humans and on micro-organisms commonly used to evaluate the effectiveness of disinfecting agents.Methods: Five sets of dentine bonding agents and

C. J. Palenik; J. C. Setcos

1996-01-01

72

Workshop report: the 2012 antimicrobial agents in veterinary medicine: exploring the consequences of antimicrobial drug use: a 3-D approach.  

PubMed

Antimicrobial resistance is a global challenge that impacts both human and veterinary health care. The resilience of microbes is reflected in their ability to adapt and survive in spite of our best efforts to constrain their infectious capabilities. As science advances, many of the mechanisms for microbial survival and resistance element transfer have been identified. During the 2012 meeting of Antimicrobial Agents in Veterinary Medicine (AAVM), experts provided insights on such issues as use vs. resistance, the available tools for supporting appropriate drug use, the importance of meeting the therapeutic needs within the domestic animal health care, and the requirements associated with food safety and food security. This report aims to provide a summary of the presentations and discussions occurring during the 2012 AAVM with the goal of stimulating future discussions and enhancing the opportunity to establish creative and sustainable solutions that will guarantee the availability of an effective therapeutic arsenal for veterinary species. PMID:24387782

Martinez, M; Blondeau, J; Cerniglia, C E; Fink-Gremmels, J; Guenther, S; Hunter, R P; Li, X-Z; Papich, M; Silley, P; Soback, S; Toutain, P-L; Zhang, Q

2014-02-01

73

Evaluation of three medicinal plants for anti-microbial activity.  

PubMed

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

2012-07-01

74

Nasal Carriage in Vietnamese Children of Streptococcus pneumoniae Resistant to Multiple Antimicrobial Agents  

Microsoft Academic Search

Resistance to antimicrobial agents in Streptococcus pneumoniae is increasing rapidly in many Asian coun- tries. There is little recent information concerning resistance levels in Vietnam. A prospective study of pneu- mococcal carriage in 911 urban and rural Vietnamese children, of whom 44% were nasal carriers, was per- formed. Carriage was more common in children <5 years old than in those

CHRISTOPHER M. PARRY; T. S. Diep; J. Wain; N. T. T. Hoa; MARY GAINSBOROUGH; DIEM NGA; CATRIN DAVIES; NGUYEN HOAN PHU; TRAN TINH HIEN; NICHOLAS J. WHITE; JEREMY J. FARRAR

2000-01-01

75

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

76

In Vitro Skin Permeation and Bioassay of Chlorhexidine Phosphanilate, a New Antimicrobial Agent  

Microsoft Academic Search

An in vitro technique was developed to study the permeation and antimicrobial activity of graded concentrations of a new antibacterial agent, chlorhexidine phosphanilate (CHP), in cream formulations using Franz diffusion cells. Formulations containing from 0.2 to 2% CHP were quantitatively applied to intact excised skin and to skin from which the stratum corneum and partial epidermis had been enzymatically removed.

Jonas C. T. Wang; Robert R. Williams; Lotte Wang; John Loder

1990-01-01

77

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

Microsoft Academic Search

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

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

2003-01-01

78

In vitro and in vivo effects of antimicrobial agents on viability of Cryptobia salmositica (Sarcomastigophora: Kinetoplastida)  

Microsoft Academic Search

Cryptobia salmositica (Sarcomastigophora: Kinetoplastida) from blood of infected rainbow trout (blood forms) or cultures (culture forms) rounded up when incubated in vitro with a combination of Penicillin, Streptomycin and Arnphotericin B (antimicrobial agents, AM). Trypan blue dye exclusion test showed that slender forms did not take up the dye whereas many round forms became coloured as incubation proceeded. Culture forms

Philip T. Thomas; Patrick T. K. Woo

1991-01-01

79

Screening of some indigenous Qatari medicinal plants for antimicrobial activity.  

PubMed

Aqueous, ethanol and butanol crude extracts of the aerial parts of ten plants exhibited variable degrees of antimicrobial activity against four bacterial and two fungal species. Aqueous extracts had low antimicrobial activity against E.coli, P.aeruginosa, B. cerreus, S.aureus, C.albicans and A.flavus. Avicennia marina (AM) aqueous extract exhibited a moderate antifungal activity. Ethanol and butanol crude extracts exhibited an improved antimicrobial activity. However, butanol exhibited a superior antimicrobial activity compared with aqueous and ethanol crudes. Compared with the standard antibiotics tested the butanol extract had the highest activity. Butanol extracts at 2000 microg/disc of AM, Lotus halophilus (LA), Pulicaria gnaphaloides (PG) and Capparis spinosa (CS) had a very good antibacterial activity against both gram-positive and -negative bacteria as well as moderate to good antifungal activity against C. albicans and A. flavus. Medicago laciniata (ML), Limonium axillare (LA) and (PG) butanol crude extract compared with standard chloramphenicol, tetracycline and nalidixic acid exhibited a superior antifungal activity. PMID:12458480

Mahasneh, Adel M

2002-12-01

80

Antimicrobial activities of southern Nepalese medicinal plants.  

PubMed

In an ethnopharmacological screening of selected medicinal plants used in Nepal, methanol extracts from 20 plant species were assayed for activity against eleven strains of bacteria and four strains of fungi. Duplicate assays were conducted with and without exposure to ultraviolet (UV)-A radiation to test for light-activated or light-enhanced activity. Fifteen of the extracts showed activity against bacteria and fourteen showed activity against fungi. Five extracts were active only when exposed to UV-A light, and the antibiotic or antifungal effect of five extracts was enhanced upon exposure to light. Two of the most active extracts were from plants used to treat diarrhoea and dysentery. Bark from both Terminalia alata (Combretaceae) and Mallotus phillppensis (Euphorbiaceae) was active against Gram-positive and Gram-negative bacteria. PMID:8866730

Taylor, R S; Edel, F; Manandhar, N P; Towers, G H

1996-02-01

81

Lycopersicon esculentum seeds: an industrial byproduct as an antimicrobial agent.  

PubMed

Lycopersicon esculentum (tomato) fruit is a widely studied matrix. However, only few works focus their attention on its seeds, which constitute a major byproduct of the tomato processing industry. In this study the antimicrobial potential of ten different tomato seed extracts from "Bull's heart" and "Cherry" varieties were analyzed against Gram-positive (Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus, Enterococcus faecalis and Bacillus cereus) and Gram-negative (Proteus mirabilis, Escherichia coli, Pseudomonas aeruginosa and Salmonella typhimurium) bacteria and fungi (Candida albicans, Aspergillus fumigatus and Trichophyton rubrum). Regarding antibacterial capacity, the different extracts were revealed to be active only against Gram-positive bacteria, E. faecalis being the most susceptible one (MIC: 2.5-10 mg/mL). Concerning antifungal activity, "Bull's heart" extracts were the most active. In a general way C. albicans was the most susceptible species (MIC: 5-10 mg/mL). The chemical composition of the extracts was also pursued, concerning organic acids, phenolics and fatty acids, in order to establish a possible relationship with the observed antimicrobial effect. PMID:20707344

Taveira, Marcos; Silva, Luís R; Vale-Silva, Luís A; Pinto, Eugénia; Valentăo, Patrícia; Ferreres, Federico; Guedes de Pinho, Paula; Andrade, Paula B

2010-09-01

82

Metabolic network analysis-based identification of antimicrobial drug targets in category A bioterrorism agents.  

PubMed

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

83

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 Povoa; Hamerski, Lidilhone; Garcez, Walmir Silva; Batista, Ana Lucia; Chang, Marilene Rodrigues; Pott, Vali Joana; Garcez, Fernanda Rodrigues

2012-01-01

84

Sweetening agents of plant origin  

Microsoft Academic Search

The most important sweet substance known is sucrose, which is obtained commercially from sugar cane and sugar beet. Because the intake of sucrose has been associated with a number of adverse effects on health, an intensive search has been undertaken to find alternative substances to satisfy the human craving for a sweet taste. Many other plant?derived compounds are sweet, ranging

A. Douglas Kinghora; Djaja D. Soejarto; George E. Inglett

1986-01-01

85

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

86

Antimicrobial activity of selected South African medicinal plants  

PubMed Central

Background Nearly 3,000 plant species are used as medicines in South Africa, with approximately 350 species forming the most commonly traded and used medicinal plants. In the present study, twelve South African medicinal plants were selected and tested for their antimicrobial activities against eight microbial species belonging to fungi, Mycobacteria, Gram-positive and Gram-negative bacteria. Methods The radiometric respiratory technique using the BACTEC 460 system was used for susceptibility testing against Mycobacterium tuberculosis, and the liquid micro-broth dilution was used for other antimicrobial assays. Results The results of the minimal inhibitory concentration (MIC) determinations indicated that the methanol extracts from Acacia karoo, Erythrophleum lasianthum and Salvia africana were able to prevent the growth of all the tested microorganisms. All other samples showed selective activities. MIC values below 100??g/ml were recorded with A. karoo, C. dentate, E. lasianthum, P. obligun and S. africana on at least one of the nine tested microorganisms. The best activity (MIC value of 39.06??g/ml) was noted with S. africana against E. coli, S. aureus and M. audouinii, and Knowltonia vesitoria against M. tuberculosis. Conclusion The overall results of the present work provide baseline information for the possible use of the studied South African plant extracts in the treatment of microbial infections. PMID:22704594

2012-01-01

87

In vitro testing of antimicrobial agents for proliferative enteropathy (ileitis)  

Microsoft Academic Search

Summary: Proliferative enteropathy (ileitis) is a common disease of grower and finisher pigs. Recent studies by the au- thors have illustrated reliable methods of in vitro culture of the etiologic agent, an obligate intracellular bacterium, known as ileal symbiont (IS) intracellularis.Characteristic le- sions of proliferative enteropathy are reproduced when IS intracellularis is used as oral inocula in challenge experi- ments

Steven McOrist; Connie J. Gebhart

88

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

89

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

90

Proposed quality control guidelines for National Committee for Clinical Laboratory Standards Susceptibility Tests using the veterinary antimicrobial agent tiamulin  

Microsoft Academic Search

Quality control guidelines for standardized antimicrobial susceptibility test methods are critical for the continuing accuracy of these clinical tests. In this report, quality control limits were proposed for the veterinary antimicrobial agent tiamulin with minimum inhibitory concentration (MIC) ranges of three or four log2 dilution steps in two different medium formulations. Disk diffusion zone diameter ranges were proposed for tiamulin

Michael A Pfaller; Ronald N Jones; Donald H Walter

2001-01-01

91

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

Microsoft Academic Search

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

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

1999-01-01

92

The therapeutic effect of 16 antimicrobial agents on Cryptosporidium infection in mice.  

PubMed

The therapeutic efficiency of 16 anti-microbial agents (Ethopabate, Nicarbazin, Sulphaquinoxaline, Furaltadone, Enterolyte-N, Sulphamethazine, Trinamide, Amprol, Phenamidine, Zoaquin, Halofuginone, Salinomycin, Monensin, Emtryl, Arprinocid and Amprolium) were examined against Cryptosporidium infections in mice. The Cryptosporidium was originally isolated from a field outbreak of calf diarrhoea. The drugs neither prevented nor modified the course of the infection as compared with infected, untreated mice. PMID:7115220

Tzipori, S R; Campbell, I; Angus, K W

1982-04-01

93

Noncytotoxic Combinations of Topical Antimicrobial Agents for Use with Cultured Skin Substitutes  

Microsoft Academic Search

Cultured skin grafts are destroyed more easily than split-thickness skin grafts by common burn wound organisms, including gram-negative and gram-positive bacteria and fungi. To increase the survival and engraftment of cultured skin grafts, formulations of antimicrobial agents were tested for cytotoxicity to cultured human keratinocytes andfibroblasts and for activity against common organisms from burn wounds. On the basis of previous

STEVEN T. BOYCE; GLENN D. WARDEN; ANDIAN ALAN HOLDER

1995-01-01

94

Inhibition of biofilm formation on silicone rubber samples using various antimicrobial agents  

Microsoft Academic Search

High-temperature-cured silicone rubber samples (silicone rubber (SIR) based on polydimethylsiloxane (PDMS)) and SIR samples containing three different antimicrobial agents, sodium benzoate (NaB), DCOIT (4,5 Dichloro-2-octyl-2H-isothiazolone-one) and p-aminobenzoic acid (PABA) were inoculated with fungal spore suspensions and incubated for 28 days at 29±1°C and ?90% humidity, according to the ISO 846:1997(E) protocol. Prior to the biodegradation test, a powder test was

S. Atarijabarzadeh; E. Strömberg; S. Karlsson

2011-01-01

95

In vitro activity of A-86719.1, a novel 2-pyridone antimicrobial agent.  

PubMed Central

This study evaluated the in vitro activity of A-86719.1, a novel 2-pyridone antimicrobial agent. The drug inhibited all tested members of the family Enterobacteriaceae at < or = 0.5 microgram/ml and all tested Pseudomonas aeruginosa, Burkholderia (Pseudomonas) cepacia, and Xanthomonas maltophilia strains at < or = 2 micrograms/ml. All but two strains of gram-positive bacteria were inhibited by < or = 1 microgram of the new drug per ml, including isolates highly resistant to ciprofloxacin. PMID:7785983

Eliopoulos, G M; Wennersten, C B; Cole, G; Chu, D; Pizzuti, D; Moellering, R C

1995-01-01

96

Synergism between plant extract and antimicrobial drugs used on Staphylococcus aureus diseases  

Microsoft Academic Search

Searches for substances with antimicrobial activity are frequent, and medicinal plants have been considered interesting by some researchers since they are frequently used in popular medicine as remedies for many infectious diseases. The aim of this study was to verify the synergism between 13 antimicrobial drugs and 8 plant extracts - \\

Joyce Elaine Cristina Betoni; Rebeca Passarelli Mantovani; Lidiane Nunes Barbosa; Luiz Claudio Di Stasi; Ary Fernandes Junior

2006-01-01

97

Metabolomics Reveals the Origins of Antimicrobial Plant Resins Collected by Honey Bees  

E-print Network

Metabolomics Reveals the Origins of Antimicrobial Plant Resins Collected by Honey Bees Michael B of antimicrobial plant resins in honey bee, Apis mellifera, nests has important physiological benefits. Resin varied in inhibition of the bee bacterial pathogen, Paenibacillus larvae. We conclude that honey bees

Weiblen, George D

98

Perspectives and concerns regarding antimicrobial agent shortages among infectious disease specialists.  

PubMed

Antimicrobial shortages have made treating certain infections more difficult. A web-based survey asking about experience with antimicrobial drug shortages was distributed in 2011 to 1328 infectious diseases physician members of the Emerging Infectious Diseases Network of the Infectious Diseases Society of America. A majority (78%) of 627 respondents reported needing to modify antimicrobial choices because of drug shortages within the past 2 years. Antimicrobials most often reported as not available or available but in short supply were trimethoprim-sulfamethoxazole injection (by 65% of respondents), amikacin (by 58%), aztreonam (by 31%), and foscarnet (by 22%). Most respondents (55%) reporting a shortage indicated that the shortage adversely affected patient outcomes and that they were forced to use alternative and second line agents which were either less effective, more toxic, or more costly. Most (70%) indicated that they learned about the shortage from contact with the pharmacy after trying to prescribe a drug in short supply. More effective means of informing physicians about drug shortages is critical to lessen the impact on patient care. PMID:23305775

Gundlapalli, Adi V; Beekmann, Susan E; Graham, Donald R; Polgreen, Philip M

2013-03-01

99

Antimicrobial activity of essential oils and other plant extracts.  

PubMed

The antimicrobial activity of plant oils and extracts has been recognized for many years. However, few investigations have compared large numbers of oils and extracts using methods that are directly comparable. In the present study, 52 plant oils and extracts were investigated for activity against Acinetobacter baumanii, Aeromonas veronii biogroup sobria, Candida albicans, Enterococcus faecalis, Escherichia col, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella enterica subsp. enterica serotype typhimurium, Serratia marcescens and Staphylococcus aureus, using an agar dilution method. Lemongrass, oregano and bay inhibited all organisms at concentrations of < or = 2.0% (v/v). Six oils did not inhibit any organisms at the highest concentration, which was 2.0% (v/v) oil for apricot kernel, evening primrose, macadamia, pumpkin, sage and sweet almond. Variable activity was recorded for the remaining oils. Twenty of the plant oils and extracts were investigated, using a broth microdilution method, for activity against C. albicans, Staph. aureus and E. coli. The lowest minimum inhibitory concentrations were 0.03% (v/v) thyme oil against C. albicans and E. coli and 0.008% (v/v) vetiver oil against Staph. aureus. These results support the notion that plant essential oils and extracts may have a role as pharmaceuticals and preservatives. PMID:10438227

Hammer, K A; Carson, C F; Riley, T V

1999-06-01

100

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, Eulalia Azevedo

2012-01-01

101

Viability of Bacteria in High-Speed Dental Drill Aerosols with Antimicrobial Agents in the Water Coolant System  

Microsoft Academic Search

Antimicrobial agents were used in the water coolant system in the high-speed dental drill during a series of tooth preparations on a model. Artificial saliva was applied to the dentition before the procedure began. For five minutes after cessation of drilling, the aerosols generated were collected on precipitation plates. Six agents reduced the bacterial counts to levels less than that

Barry H. Grayson; William K. P. Li; M. A. Benjaminson

1973-01-01

102

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

103

Noncytotoxic combinations of topical antimicrobial agents for use with cultured skin substitutes.  

PubMed Central

Cultured skin grafts are destroyed more easily than split-thickness skin grafts by common burn wound organisms, including gram-negative and gram-positive bacteria and fungi. To increase the survival and engraftment of cultured skin grafts, formulations of antimicrobial agents were tested for cytotoxicity to cultured human keratinocytes and fibroblasts and for activity against common organisms from burn wounds. On the basis of previous studies, a base formulation containing neomycin (40 micrograms/ml), polymyxin B (700 U/ml), and mupirocin (40 micrograms/ml) was prepared, to which ciprofloxacin (20 micrograms/ml) or norfloxacin (20 micrograms/ml) and amphotericin B (0.25 microgram/ml) or nystatin (100 U/ml) were added. Toxicity to cultured human cells was determined by the growth response of cell cultures (n = 6) to each drug combination over 4 days. Activity against clinical isolates (n = 40) of Staphylococcus aureus, Pseudomonas aeruginosa, other gram-negative bacteria, and Candida spp. was determined by the wet disc assay. Analysis of variance testing showed no significant differences in the growth of keratinocytes or fibroblasts under control or experimental conditions. Medium without antimicrobial agents was not effective against any of the 40 microbial strains tested. The base formulation was effective against all bacterial strains tested but against none of the fungi, while all experimental formulations were effective against all microbial strains tested. These findings suggest that neomycin, mupirocin, and polymyxin B may be combined with a quinolone and an antimycotic agent to provide broad antimicrobial activity for a formulation for topical use with cultured skin on burns. However, the formulations described here are strictly experimental and are not recommended for clinical use without further evaluation. PMID:7574524

Boyce, S T; Warden, G D; Holder, I A

1995-01-01

104

In Vitro Susceptibility of Mycoplasma hyopneumoniae and Mycoplasma hyorhinis to Fifty-One Antimicrobial Agents  

PubMed Central

By a tube dilution assay technique, 51 antimicrobial agents were singly tested against 9 strains of Mycoplasma hyopneumoniae and 1 strain of M. hyorhinis for the purpose of obtaining information useful for selecting an agent for testing in vivo against porcine mycoplasmal pneumonia. Based on determining minimal inhibitory concentrations and chemically grouping the agents into nine classes, all M. hyopneumoniae strains were found resistant to penicillins and peptides and susceptible to sulfonamides and tetracyclines, and, in other classes, were either susceptible or resistant depending on the particular agent being tested. Strains were susceptible to the same 33 of the 51 agents. Minimal inhibitory concentrations ranged from 0.06 to 9.20 ?g/ml. M. hyorhinis was susceptible to 19 of the 33 agents that M. hyopneumoniae was susceptible to. Minimal inhibitory concentrations ranged from 0.03 to 8.10 ?g/ml. All strains of M. hyopneumoniae differed from M. hyorhinis in that they were susceptible to cephaloglycin and nitrofurazone. PMID:697348

Williams, Phletus P.

1978-01-01

105

In vitro activity of A-56619 and A56620, two new aryl-fluoroquinolone antimicrobial agents.  

PubMed Central

The in vitro antimicrobial activity of two new aryl-fluoroquinolone antibiotics, A-56619 and A-56620, was compared with those of norfloxacin and several other antibiotics against 448 bacterial isolates. A-56620 was the most active agent tested. The usual 90% MIC of A-56620 was less than or equal to 2 micrograms/ml, except for enterococci, gentamicin-resistant Serratia marcescens, and gentamicin-resistant Pseudomonas aeruginosa, for which the 90% MIC was 4 micrograms/ml. A-56619 and norfloxacin were generally severalfold less active than A-56620. Cross resistance was observed between the quinolone antibiotics and other unrelated antibiotic classes. PMID:3717937

Smith, B R; LeFrock, J L; Donato, J B; Joseph, W S; Weber, S J

1986-01-01

106

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

107

Comparative Activity of Eighteen Antimicrobial Agents against Anaerobic Bacteria Isolated in South Africa  

Microsoft Academic Search

The in vitro activity of 18 antimicrobial agents was determined against 378 anaerobic bacteria isolated in Bloemfontein,\\u000a South Africa, during 1996\\/97. Against the gram-positive isolates, MICs of penicillin and cefoxitin were >0.5??g\\/ml and >16??g\\/ml,\\u000a respectively, for five and three strains of non-perfringens Clostridium spp. Seventeen Peptostreptococcus anaerobius strains were resistant to penicillin (MIC?2??g\\/ml). All gram-positive anaerobes tested except one Peptostreptococcus

M. M. Lubbe; P. L. Botha; L. J. Chalkley

1999-01-01

108

Antimicrobial resistance in Escherichia coli isolated in inflow, effluent and sludge from municipal wastewater treatment plants  

Microsoft Academic Search

Antimicrobial resistance is a phenomenon of increasing importance. Sewage treatment processes are a vehicle for dissemination of resistant bacteria in both aquatic and terrestrial environments. To assess the number of antimicrobial resistant E. coli present in the wastewater inflow, effluent and sludge from urban sewage treatment plants in Portugal, 42 samples of crude inflow, treated effluent and sludge were collected

P. Martins Da Costa; P. Vaz-Pires; F. Bernardo

2007-01-01

109

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

. Naturally occurring antimicrobial peptides (AMPs), also known as host defense peptides, serve as the first have alkyl modifications as well (22, 27). The antimicrobial activity of these natural toxins, whichANTIMICROBIAL AGENTS AND CHEMOTHERAPY, June 2011, p. 3058­3062 Vol. 55, No. 6 0066

Barron, Annelise E.

110

Plant pathogens as biocontrol agents of Cirsium arvense an overestimated approach? 1 Plant pathogens as biocontrol agents of  

E-print Network

Plant pathogens as biocontrol agents of Cirsium arvense ­ an overestimated approach? 1 Plant pathogens as biocontrol agents of Cirsium arvense ­ an overestimated approach? Esther Müller1 , Wolfgang: Müller E, Nentwig W (2011) Plant pathogens as biocontrol agents of Cirsium arvense ­ an overestimated

Richner, Heinz

111

Synthesis and biological evaluation of pyrazoline derivatives bearing an indole moiety as new antimicrobial agents.  

PubMed

1-(p-Methylphenyl)-3,5-diaryl-2-pyrazoline derivatives (2a-f) were synthesized via the treatment of 1-(1H-indol-3-yl)-3-aryl-2-propen-1-ones (1a-f) with p-methylphenylhydrazine hydrochloride in hot acetic acid. The structures of these compounds were elucidated by IR, ąH NMR, and mass spectral data and elemental analysis. These compounds were investigated for their antimicrobial activity. Brine-Shrimp lethality assay was carried out to determine the toxicity of the compounds. Compound 2e, which is the pyrazoline derivative bearing the 2,5-dichlorophenyl moiety, can be identified as the most promising agent against Klebsiella pneumoniae (ATCC 13883) and Candida glabrata (ATCC 36583) due to its inhibitory effects on K. pneumoniae and C. glabrata with a MIC value of 100 µg/mL as a non-toxic agent (LC?? > 1000 µg/mL). PMID:23681942

Özdemir, Ahmet; Altintop, Mehlika Dilek; Kaplanc?kl?, Zafer Asim; Turan-Zitouni, Gülhan; Karaca, Hülya; Tunal?, Ya?mur

2013-06-01

112

The use of angiogenic-antimicrobial agents in experimental wounds in animals: problems and solutions.  

PubMed

A topical combination (silvathymosin) of natural proangiogeneic protein thymosin ?4 (T?4) and antimicrobial silver sulfadiazine was hypothesized to promote the healing of large, full-thickness, clean or infected wounds in rats. Silvathymosin showed the fastest wound healing (85%) followed by silver sulfadiazine (84%) and T?4 (72%). In the infected groups, the healing pattern was different, as T?4 and silvathymosin groups did not show similar wound healing. Wound histopathology and VEGF and KI67 immunohistochemical assessment of angiogenesis was consistent and correlated well with the tempo of healing of the acute wounds. These preliminary data demonstrate the more rapid acute wound healing properties of the combination formulation of thymosin ?4 and silver sulfadiazine as compared to these agents alone. This novel agent could prove an effective treatment modality for debilitating chronic wounds and decubitus ulcers. PMID:23050814

Suman, Paritosh; Ramachandran, Harikrishnan; Sahakian, Sossy; Gill, Kamraan Z; Horst, Basil A J; Modak, Shanta M; Hardy, Mark A

2012-10-01

113

1,2,3-Triazole-derived naphthalimides as a novel type of potential antimicrobial agents: synthesis, antimicrobial activity, interaction with calf thymus DNA and human serum albumin.  

PubMed

A series of 1,2,3-triazole-derived naphthalimides as a novel type of potential antimicrobial agents were synthesized and characterized by IR, NMR and HRMS spectra. All the new compounds were screened for their antimicrobial activity against four Gram-positive bacteria, four Gram-negative bacteria and three fungi. Bioactive assay manifested that 3,4-dichlorobenzyl compound 9e and its corresponding hydrochloride 11e showed better anti-Escherichia coli activity than Norfloxacin and Chloromycin. Preliminary research revealed that compound 9e could effectively intercalate into calf thymus DNA to form compound 9e-DNA complex which might block DNA replication and thus exert antimicrobial activities. Human serum albumin could effectively store and carry compound 9e by electrostatic interaction. PMID:24295786

Lv, Jing-Song; Peng, Xin-Mei; Kishore, Baathulaa; Zhou, Cheng-He

2014-01-01

114

Antimicrobial and cytotoxic activities screening of some Brazilian medicinal plants used in Governador Valadares district  

Microsoft Academic Search

Ethanol extracts from medicinal plants commonly used by Governador Valadares people were tested for antimicrobial activity and cytotoxicity (BST assay). The field survey was conducted during the years 1997-2000 by means of direct interviews with healing men (\\

Beatriz Gonçalves Brasileiro; Virgínia Ramos Pizziolo; Délio Soares Raslan; Claudia Mashrouah Jamal; Dâmaris Silveira

2006-01-01

115

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

116

French Multicenter Study Involving Eight Test Sites for Radiometric Determination of Activities of 10 Antimicrobial Agents againstMycobacterium aviumComplex  

Microsoft Academic Search

The radiometric BACTEC 460-TB methodology hasfilled an increased need in the screening of a wide range of antimicrobial agents against Mycobacterium avium (MAC) isolates on a patient-to-patient basis. In this context, a multicenter study involving eight test sites across France was performed to determine the MICs of 10 antimicrobial agents for MAC organisms. The aim of the investigation was to

NALIN RASTOGI; ROSINE-MARIE BAURIAUD; ANNE BOURGOIN; BERNARD CARBONNELLE; CLAUDE CHIPPAUX; MARIE-JOSE GEVAUDAN; KHYE SENG GOH

117

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

E-print Network

An investigation of the 6ag inner valence orbital electron density of the antimicrobial agent orbital momentum profile of the antimicrobial agent diacetyl, also known as 2,3-butanedione (CH3COCOCH3 supported by the National Natural Science Foundation of China under Grant Nos. 19854002, 19774037

Wang, Yayu

118

ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, July 2008, p. 26162625 Vol. 52, No. 7 0066-4804/08/$08.00 0 doi:10.1128/AAC.01643-07  

E-print Network

ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, July 2008, p. 2616­2625 Vol. 52, No. 7 0066-4804/08/$08.00 0 represents the main reservoir of the bacterium. The rates of recovery of A. baumannii from natural is high and its occurrence in the hospital setting is frequent (15). Resistance to antimicrobial agents

Dever, Jennifer A.

119

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

Microsoft Academic Search

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

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

2006-01-01

120

Antibacterial activity of the recombinant antimicrobial peptide Ib-AMP4 from Impatiens balsamina and its synergy with other antimicrobial agents against drug resistant bacteria.  

PubMed

Ib-AMP4 is an antimicrobial peptide of Impatiens balsamina (Balsaminaceae). Ib-AMP4 was produced as a recombinant peptide and in this study its antimicrobial activity against human bacterial pathogens was investigated. Ib-AMP4 was bactericidal against both Gram positive and Gram negative bacteria with MIC values between 0.49 and 3.5 microM in sensitive species. A genuine synergistic effect was achieved when IB-AMP4 was employed in combination with the plant monoterpene thymol against drug-resistant Klebsiella pneumoniae (KPC) ATCC700603, or with the antibiotics vancomycin or oxacillin against Enterococcus faecalis (VRE) ATCC51299. PMID:23923648

Fan, X; Reichling, J; Wink, M

2013-07-01

121

Tri- and tetra-nuclear polypyridyl ruthenium(ii) complexes as antimicrobial agents.  

PubMed

A series of inert tri- and tetra-nuclear polypyridylruthenium(ii) complexes that are linked by the bis[4(4'-methyl-2,2'-bipyridyl)]-1,n-alkane ligand ("bbn" for n = 10, 12 and 16) have been synthesised and their potential as antimicrobial agents examined. Due to the modular nature of the synthesis of the oligonuclear complexes, it was possible to make both linear and non-linear tetranuclear ruthenium species. The minimum inhibitory concentrations (MIC) of the ruthenium(ii) complexes were determined against four strains of bacteria - Gram positive Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus (MRSA), and Gram negative Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa). In order to gain an understanding of the relative antimicrobial activities, the cellular uptake and water-octanol partition coefficients (log?P) were determined for a selection of the ruthenium complexes. Although the trinuclear complexes were the most lipophilic based upon log?P values and showed the greatest cellular uptake, the linear tetranuclear complexes were generally more active, with MIC values <1 ?M against the Gram positive bacteria. Similarly, although the non-linear tetranuclear complexes were slightly more lipophilic and were taken up to a greater extent by the bacteria, they were consistently less active than their linear counterparts. Of particular note, the cellular accumulation of the oligonuclear ruthenium complexes was greater in the Gram negative strains compared to that in the Gram positive S. aureus and MRSA. The results demonstrate that the lower antimicrobial activity of polypyridylruthenium(ii) complexes towards Gram negative bacteria, particularly P. aeruginosa, is not strongly correlated to the cellular accumulation but rather to a lower intrinsic ability to kill the Gram negative cells. PMID:25271478

Gorle, Anil K; Feterl, Marshall; Warner, Jeffrey M; Wallace, Lynne; Keene, F Richard; Collins, J Grant

2014-10-22

122

Antimicrobial activity and phytochemical analysis of crude extracts and essential oils from medicinal plants.  

PubMed

We aimed to establish a phytochemical analysis of the crude extracts and performed GC-MS of the essential oils (EOs) of Eugenia uniflora L. (Myrtaceae) and Asteraceae species Baccharis dracunculifolia DC, Matricaria chamomilla L. and Vernonia polyanthes Less, as well as determining their antimicrobial activity. Establishment of the minimal inhibitory concentrations of the crude extracts and EOs against 16 Staphylococcus aureus and 16 Escherichia coli strains from human specimens was carried out using the dilution method in Mueller-Hinton agar. Some phenolic compounds with antimicrobial properties were established, and all EOs had a higher antimicrobial activity than the extracts. Matricaria chamomilla extract and E. uniflora EO were efficient against S. aureus strains, while E. uniflora and V. polyanthes extracts and V. polyanthes EO showed the best antimicrobial activity against E. coli strains. Staphylococcus aureus strains were more susceptible to the tested plant products than E. coli, but all natural products promoted antimicrobial growth inhibition. PMID:22007687

Silva, N C C; Barbosa, L; Seito, L N; Fernandes, A

2012-01-01

123

Effect of Antimicrobial Agents on MinD Protein Oscillations in E. coli Bacterial Cells  

NASA Astrophysics Data System (ADS)

The pole-to-pole oscillation of MinD proteins in E. coli cells determines the location of the division septum, and is integral to healthy cell division. It has been shown previously that the MinD oscillation period is approximately 40 s for healthy cells [1] but is strongly dependant on environmental factors such as temperature, which may place stress on the cell [2,3]. We use a strain of E. coli in which the MinD proteins are tagged with green fluorescent protein (GFP), allowing fluorescence visualization of the MinD oscillation. We use high-resolution total internal reflection fluorescence (TIRF) microscopy and a custom, temperature controlled flow cell to observe the effect of exposure to antimicrobial agents on the MinD oscillation period and, more generally, to analyze the time variation of the spatial distribution of the MinD proteins within the cells. These measurements provide insight into the mechanism of antimicrobial action. [1] Raskin, D.M.; de Boer, P. (1999) Proc. Natl. Acad. Sci. 96: 4971-4976. [2] Touhami, A.; Jericho, M; Rutenberg, A. (2006) J. Bacteriol. 188: 7661-7667. [3] Downing, B.; Rutenberg, A.; Touhami, A.; Jericho, M. (2009) PLoS ONE 4: e7285.

Kelly, Corey; Giuliani, Maximiliano; Dutcher, John

2012-02-01

124

Effect of Antimicrobial Agents on MinD Protein Oscillations in E. coli Bacterial Cells  

NASA Astrophysics Data System (ADS)

The pole-to-pole oscillation of the MinD proteins in E. coli determines the location of the division septum, and is integral to healthy cell division. It has been shown previously that the MinD oscillation period is approximately 40 s for healthy cells [1] but is strongly dependant on environmental factors such as temperature, which may place stress on the cell [2,3]. We use a strain of E. coli in which the MinD proteins are tagged with green fluorescent protein (GFP), allowing fluorescence visualization of the MinD oscillation. We use high resolution total internal reflection fluorescence (TIRF) microscopy to observe the effect of exposure to antimicrobial agents on the MinD oscillation period and, more generally, to analyze the time variation of the spatial distribution of the MinD proteins within the cells. These measurements provide insight into the mechanism of antimicrobial action. [4pt] [1] Raskin, D.M.; de Boer, P. (1999) Proc Natl. Acad. Sci. 96: 4971-4976.[0pt] [2] Colville, K.; Tompkins, N.; Rutenberg, A. D.; Jericho, M. H. (2010) Langmuir 2010:26.[0pt] [3] Downing, B.; Rutenberg, A.; Touhami, A.; Jericho, M. (2009) PLoS ONE 4: e7285.

Kelly, Corey; Murphy, Megan; Giuliani, Maximiliano; Dutcher, John

2011-03-01

125

Phyllanthus wightianus Müll. Arg.: a potential source for natural antimicrobial agents.  

PubMed

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

126

Secular trends in severe renal failure associated with the use of new antimicrobial agents in critically ill surgical patients  

Microsoft Academic Search

Randomized controlled trials conducted since 2000 have shown that new antibacterial and antifungal agents may reduce the frequency\\u000a of kidney injury in selected groups of critically ill patients, yet it is unclear whether these benefits translate to the\\u000a clinical setting. The aim of the present study was to evaluate longitudinally the successive routine implementation of new\\u000a antimicrobial agents (caspofungin, voriconazole,

M. E. Eichhorn; H. Wolf; H. Küchenhoff; M. Joka; K.-W. Jauch; W. H. Hartl

2007-01-01

127

In vitro activities of 10 antimicrobial agents against bacterial vaginosis-associated anaerobic isolates from pregnant Japanese and Thai women.  

PubMed

The in vitro activities of 10 antimicrobial agents against 159 bacterial vaginosis-associated anaerobic isolates from pregnant Japanese and Thai women were determined. Clindamycin, imipenem, cefmetazole, amoxicillin, amoxicillin-clavulanate, and metronidazole were highly active against all anaerobic isolates except Prevotella bivia and Mobiluncus species, which were resistant to amoxicillin and metronidazole, respectively. Cefotiam, ceftazidime, and ofloxacin were variably effective, while cefaclor was the least effective agent. PMID:9333068

Puapermpoonsiri, S; Watanabe, K; Kato, N; Ueno, K

1997-10-01

128

Sparfloxacin-metal complexes as antifungal agents - Their synthesis, characterization and antimicrobial activities  

NASA Astrophysics Data System (ADS)

Metal complexes with the third-generation quinolone antibacterial agent sparfloxacin (SPFX) or 5-amino-1-cyclopropyl-7-(cis-3,5-dimethyl-1-piperazinyl)-6,8,di-fluoro-1-4-dihydro-4-oxo-3-quinocarboxylic acid have been synthesized and characterized with physicochemical and spectroscopic techniques such as TLC, IR, NMR and elemental analyses. In these complexes, sparfloxacin acts as bidentate deprotonated ligands bound to the metal through the pyridone oxygen and one carboxylate oxygen. The antimicrobial activity of these complexes has been evaluated against four Gram-positive and seven Gram-negative bacteria. Antifungal activity against five different fungi has been evaluated and compared with reference drug sparfloxacin. Fe 2+-SPFX and Cd 2+-SPFX complexes showed remarkable potency as compared to the parent drug.

Sultana, Najma; Arayne, M. Saeed; Gul, Somia; Shamim, Sana

2010-06-01

129

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

130

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

131

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

132

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

133

Viability of Streptococcus mutans and Streptococcus sobrinus in whole saliva with varying concentrations of indigenous antimicrobial agents.  

PubMed

We have studied the possible relationship between indigenous salivary antimicrobial agents, indigenous mutans streptococci and the capability of added mutans streptococci to grow in saliva. Stimulated whole saliva was collected from 19 healthy donors. Saliva samples were sterilized, supplemented with glucose and inoculated with Streptococcus mutans or Streptococcus sobrinus. The mixtures were incubated for 20 h followed by counting of viable cells. Saliva samples were analysed, both before and after sterilization, for indigenous antimicrobial agents and the bacterial flora. The subjects could be divided into two groups: those (n = 9) whose saliva promoted and those (n = 10) whose saliva inhibited the growth of the inoculated streptococci. A statistically significant correlation (+0.82, p < 0.001) was found between the numbers of viable cells of S. mutans and S. sobrinus after incubation in saliva. The sterilization procedure reduced the content of all antimicrobial proteins. Salivary antimicrobial factors, or levels of indigenous mutans streptococci, did not differ between the two groups. We conclude that none of the individual salivary antimicrobial factors alone can explain the large individual differences in growth-promoting or growth-inhibiting patterns of saliva on S. mutans and S. sobrinus. Inter-individually, saliva either supports or inhibits the growth of mutans streptococci, indicating a similar response of these two species in relation to the properties of saliva. PMID:1334804

Lenander-Lumikari, M; Tenovuo, J; Emilson, C G; Vilja, P

1992-01-01

134

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

135

Antimicrobial activity of some ethnomedicinal plants used by Paliyar tribe from Tamil Nadu, India  

Microsoft Academic Search

BACKGROUND: Antimicrobial activity of 18 ethnomedicinal plant extracts were evaluated against nine bacterial strains (Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa, Ervinia sp, Proteus vulgaris) and one fungal strain (Candida albicans). The collected ethnomedicinal plants were used in folk medicine in the treatment of skin diseases, venereal diseases, respiratory problems and nervous disorders.

Veeramuthu Duraipandiyan; Muniappan Ayyanar; Savarimuthu Ignacimuthu

2006-01-01

136

Antimicrobial activities of extracts from tropical Atlantic marine plants against marine pathogens and saprophytes  

Microsoft Academic Search

Studies investigating disease resistance in marine plants have indicated that secondary metabolites may have important defensive functions against harmful marine microorganisms. The goal of this study was to systematically screen extracts from marine plants for antimicrobial effects against marine pathogens and saprophytes. Lipophilic and hydrophilic extracts from species of 49 marine algae and 3 seagrasses collected in the tropical Atlantic

Sebastian Engel; Melany P. Puglisi; Paul R. Jensen; William Fenical

2006-01-01

137

TOTAL PHENOLIC CONTENT, ANTIOXIDANT AND ANTIMICROBIAL ACTIVITIES OF SOME MEDICINAL PLANTS  

Microsoft Academic Search

Crude extracts from Inula aucherana, Fumaria officinalis, Crocus sativus, Vicum album, Tribulus terestris, Polygonatum multiflorum, Alkanna tinctoria and Taraxacum officinale were screened for their in vitro antioxidant and antimicrobial properties. Total phenolic content of extracts from these plants were also determined. ?-carotene bleaching assay and Folin-Ciocalteu reagent were used to determine total antioxidant activity and total phenols of plant extracts.

MEMNUNE SENGUL; HILAL YILDIZ; NEVA GUNGOR; BULENT CETIN; ZEYNEP ESER; SEZAI ERCISLI

138

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

139

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

140

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

141

Synthesis and structure-activity relationship of N-(cinnamyl) chitosan analogs as antimicrobial agents.  

PubMed

The current study focuses on the preparation of new N-(cinnamyl) chitosan derivatives as antimicrobial agents against nine types of crop-threatening pathogens. Chitosan was reacted with a set of aromatic cinnamaldehyde analogs by reductive amination involving formation of the corresponding imines, followed by reduction with sodium borohydride to produce N-(cinnamyl) chitosan derivatives. The structural characterization was confirmed by (1)H and (13)C NMR spectroscopy and the degrees of substitution ranged from 0.08 to 0.28. The antibacterial activity was evaluated in vitro by minimum inhibitory concentration (MIC) against Agrobacterium tumefaciens and Erwinia carotovora. A higher inhibition activity was obtained by N-(?-methylcinnamyl) chitosan with MIC 1275 and 1025 mg/L against A. tumefaciens and E. carotovora, respectively followed by N-(o-methoxycinnamyl) chitosan (MIC=1925 and 1550 mg/L, respectively). The antifungal assessment was evaluated in vitro by mycelial radial growth technique against Alternaria alternata, Botrytis cinerea, Botryodiplodia theobromae, Fusarium oxysporum, Fusarium solani, Pythium debaryanum and Phytophthora infestans. N-(o-methoxycinnamyl) chitosan showed the highest antifungal activity among the tested compounds against the airborne fungi A. alternata, B. cinerea, Bd. theobromae and Ph. infestans with EC?? of 672, 796, 980 and 636 mg/L, respectively. However, N-(p-N-dimethylaminocinnamyl) chitosan was the most active against the soil born fungi F. oxysporum, F. solani and P. debaryanum (EC50=411, 566 and 404 mg/L, respectively). On the other hand, the chitosan derivatives caused significant reduction in spore germination of A. alternata, B. cinerea, F. oxysporum and F. solani compared to chitosan and the reduction in spore germination was higher than that of the mycelia inhibition. The synthesis and characterization of new chitosan derivatives are ongoing in our laboratory aiming to obtain derivatives with higher antimicrobial activities and used as safe alternatives to harmful microbicides. PMID:23511055

Badawy, Mohamed E I; Rabea, Entsar I

2013-06-01

142

Pharmacodynamics of Antimicrobials against Mycoplasma mycoides mycoides Small Colony, the Causative Agent of Contagious Bovine Pleuropneumonia  

PubMed Central

Background Mycoplasma mycoides subspecies mycoides Small Colony (MmmSC) is the causative agent of Contagious Bovine Pleuropneumonia (CBPP), a disease of substantial economic importance in sub-Saharan Africa. Failure of vaccination to curtail spread of this disease has led to calls for evaluation of the role of antimicrobials in CBPP control. Three major classes of antimicrobial are effective against mycoplasmas, namely tetracyclines, fluoroquinolones and macrolides. Therefore, the objectives of this study were to determine the effector kinetics of oxytetracycline, danofloxacin and tulathromycin against two MmmSC field strains in artificial medium and adult bovine serum. Methods Minimum inhibitory concentrations (MIC) were determined for oxytetracycline, danofloxacin and tulathromycin against MmmSC strains B237 and Tan8 using a macrodilution technique, and time-kill curves were constructed for various multiples of the MIC over a 24 hour period in artificial medium and serum. Data were fitted to sigmoid Emax models to obtain 24 hour-area under curve/MIC ratios for mycoplasmastasis and, where appropriate, for mycoplasmacidal activity and virtual mycoplasmal elimination. Results Minimum inhibitory concentrations against B237 were 20-fold higher, 2-fold higher and approximately 330-fold lower in serum than in artificial medium for oxytetracycline, danofloxacin and tulathromycin, respectively. Such differences were mirrored in experiments using Tan8. Oxytetracycline was mycoplasmastatic against both strains in both matrices. Danofloxacin elicited mycoplasmacidal activity against B237 and virtual elimination of Tan8; similar maximum antimycoplasmal effects were observed in artificial medium and serum. Tulathromycin effected virtual elimination of B237 but was mycoplasmastatic against Tan8 in artificial medium. However, this drug was mycoplasmastatic against both strains in the more physiologically relevant matrix of serum. Conclusions Oxytetracycline, danofloxacin and tulathromycin are all suitable candidates for further investigation as potential treatments for CBPP. This study also highlights the importance of testing drug activity in biological matrices as well as artificial media. PMID:22952911

Mitchell, John D.; McKellar, Quintin A.; McKeever, Declan J.

2012-01-01

143

Derivatives of the Antimicrobial Peptide BP100 for Expression in Plant Systems  

PubMed Central

Production of antimicrobial peptides in plants constitutes an approach for obtaining them in high amounts. However, their heterologous expression in a practical and efficient manner demands some structural requirements such as a minimum size, the incorporation of retention signals to assure their accumulation in specific tissues, and the presence of protease cleavage amino acids and of target sequences to facilitate peptide detection. Since any sequence modification may influence the biological activity, peptides that will be obtained from the expression must be screened prior to the synthesis of the genes for plant transformation. We report herein a strategy for the modification of the antimicrobial undecapeptide BP100 that allowed the identification of analogues that can be expressed in plants and exhibit optimum biological properties. We prepared 40 analogues obtained by incorporating repeated units of the antimicrobial undecapeptide, fragments of natural peptides, one or two AGPA hinges, a Gly or Ser residue at the N-terminus, and a KDEL fragment and/or the epitope tag54 at the C-terminus. Their antimicrobial, hemolytic and phytotoxic activities, and protease susceptibility were evaluated. Best sequences contained a magainin fragment linked to the antimicrobial undecapeptide through an AGPA hinge. Moreover, since the presence of a KDEL unit or of tag54 did not influence significantly the biological activity, these moieties can be introduced when designing compounds to be retained in the endoplasmic reticulum and detected using a complementary epitope. These findings may contribute to the design of peptides to be expressed in plants. PMID:24376887

Badosa, Esther; Moiset, Gemma; Montesinos, Laura; Talleda, Montserrat; Bardaji, Eduard; Feliu, Lidia; Planas, Marta; Montesinos, Emilio

2013-01-01

144

Nitrite reductase from Pseudomonas aeruginosa released by antimicrobial agents and complement induces interleukin-8 production in bronchial epithelial cells.  

PubMed

We have recently reported that nitrite reductase, a bifunctional enzyme located in the periplasmic space of Pseudomonas aeruginosa, could induce interleukin-8 (IL-8) generation in a variety of respiratory cells, including bronchial epithelial cells (K. Oishi et al. Infect. Immun. 65:2648-2655, 1997). In this report, we examined the mode of nitrite reductase (PNR) release from a serum-sensitive strain of live P. aeruginosa cells during in vitro treatment with four different antimicrobial agents or human complement. Bacterial killing of P. aeruginosa by antimicrobial agents induced PNR release and mediated IL-8 production in human bronchial epithelial (BET-1A) cells. Among these agents, imipenem demonstrated rapid killing of P. aeruginosa as well as rapid release of PNR and resulted in the highest IL-8 production. Complement-mediated killing of P. aeruginosa was also associated with PNR release and enhanced IL-8 production. The immunoprecipitates of the aliquots of bacterial culture containing imipenem or complement with anti-PNR immunoglobulin G (IgG) induced twofold-higher IL-8 production than did the immunoprecipitates of the aliquots of bacterial culture with a control IgG. These pieces of evidence confirmed that PNR released in the aliquots of bacterial culture was responsible for IL-8 production in the BET-1A cells. Furthermore, the culture supernatants of the BET-1A cells stimulated with aliquots of bacterial culture containing antimicrobial agents or complement similarly mediated neutrophil migration in vitro. These data support the possibility that a potent inducer of IL-8, PNR, could be released from P. aeruginosa after exposure to antimicrobial agents or complement and contributes to neutrophil migration in the airways during bronchopulmonary infections with P. aeruginosa. PMID:10103183

Sar, B; Oishi, K; Wada, A; Hirayama, T; Matsushima, K; Nagatake, T

1999-04-01

145

Short communication: Streptococcus species isolated from mastitis milk samples in Germany and their resistance to antimicrobial agents.  

PubMed

Mastitis is one of the most frequent infectious diseases in dairy cattle and is a reason for antimicrobial drug usage in dairy cows. The bacteria involved in bovine mastitis are mainly Streptococcus spp., Staphylococcus spp., and coliforms. The aim of this study was to determine antimicrobial resistance among Streptococcus spp. isolated from bovine mastitis milk. Antimicrobial resistance in Strep. uberis (n=227), Strep. dysgalactiae (n=49), and Strep. agalactiae (n=3) was determined for 9 antimicrobial agents using the broth microdilution method in accordance with Clinical and Laboratory Standards Institute recommendations. Of all Streptococcus spp., 13% were multidrug resistant. The rate of multidrug resistance was higher among Strep. uberis (15%) than among Strep. dysgalactiae (6%) and Strep. agalactiae (0%). Resistance to tetracycline was the most common, followed by resistance to erythromycin, pirlimycin, and gentamicin. Resistance rates were higher on farms with more than 80 cows compared with those with fewer than 20 cows. ?-Lactams should remain the drugs of choice in the treatment of streptococcal mastitis. The slightly elevated minimum inhibitory concentrations determined for these antibiotics may indicate, however, the emergence of resistant streptococci. To identify such changes in susceptibility as early as possible, antimicrobial resistance in streptococci should be surveyed regularly. PMID:22999286

Minst, K; Märtlbauer, E; Miller, T; Meyer, C

2012-12-01

146

Expression and purification of cyto-insectotoxin (Cit1a) using silkworm larvae targeting for an antimicrobial therapeutic agent.  

PubMed

Antimicrobial peptides (AMPs), both synthetic and from natural sources, have raised interest recently as potential alternatives to antibiotics. Cyto-insectotoxin (Cit1a) is a 69-amino-acid antimicrobial peptide isolated from the venom of the central Asian spider Lachesana tarabaevi. The synthetic gene Cit1a fused with the enhanced green fluorescent protein (EGFP) gene was expressed as the EGFP-Cit1a fusion protein using a cysteine protease-deleted Bombyx mori nucleopolyhedrovirus (BmNPV-CP(-)) bacmid in silkworm larva and pupa. The antimicrobial effect of the purified protein was assayed using disk diffusion and broth microdilution methods. The minimum inhibitory concentration of EGFP-Cit1a was also measured against several bacterial strains and showed similar antimicrobial activity to that of the synthetic Cit1a reported earlier. The EGFP-Cit1a fusion protein showed antibiotic activity toward gram-positive and gram-negative bacteria at the micromolar concentration level. These results show that active Cit1a can be produced and purified in silkworm, although this peptide is insecticidal. This study demonstrates the potential of active Cit1a purified from silkworms to use as an antimicrobial agent. PMID:24728600

Ali, M P; Yoshimatsu, Katsuhiko; Suzuki, Tomohiro; Kato, Tatsuya; Park, Enoch Y

2014-08-01

147

ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, 0066-4804/01/$04.00 0 DOI: 10.1128/AAC.45.9.24412449.2001  

E-print Network

ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, 0066-4804/01/$04.00 0 DOI: 10.1128/AAC.45 (7). A large number of eukaryotic peptides and small proteins with antimicrobial activity have been- liminary results have been reported for natural peptides such as dermaseptins (19, 23), SPYY (47), cecropin

Pompeu Fabra, Universitat

148

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

PubMed

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

Schillaci, Domenico; Cusimano, Maria Grazia; Cunsolo, Vincenzo; Saletti, Rosaria; Russo, Debora; Vazzana, Mirella; Vitale, Maria; Arizza, Vincenzo

2013-01-01

149

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

150

A rapid method for screening antimicrobial agents for activities against a strain of Mycobacterium tuberculosis expressing firefly luciferase.  

PubMed Central

We developed a rapid method to screen the efficacy of antimicrobial agents against Mycobacterium tuberculosis. A restriction fragment carrying a promoterless firefly luciferase gene was cloned into a 4,488-bp shuttle vector, pMV261, and luciferase was expressed under the control of a mycobacterial heat shock promoter. The resulting plasmid, pLUC10, was introduced by electroporation into the avirulent strain M. tuberculosis H37Ra. Luciferase assays of sonic lysates of Triton X-100-treated cells of M. tuberculosis H37Ra(pLUC10) yielded bioluminescence in excess of 1,000 relative light units/approximately 10(9) tubercle bacilli, compared with 0.0025 for the same number of parental cells. A 48-h microdilution antimicrobial agent-screening assay using this strain was developed. Images PMID:8328785

Cooksey, R C; Crawford, J T; Jacobs, W R; Shinnick, T M

1993-01-01

151

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

152

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

153

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. The abnormal situation handling in industrial plants is a challenging application area due to the complexity-model, abnormal situation handling, industrial plants 1. Introduction This paper is based on the work made

154

Broth Microdilution Susceptibility Testing of Brucella Species: Quality Control Limits for Ten Antimicrobial Agents against Three Standard Quality Control Strains  

Microsoft Academic Search

Brucella broth without supplementation is the recommended medium for broth microdilution susceptibility tests of Brucella abortus, B. melitensis, and B. suis. Based on an eight-laboratory collaborative study using a pH-adjusted modification of this medium, we propose MIC quality control ranges for three control strains against 10 antimicrobials that are potentially efficacious for treating infections caused by these agents of bioterrorism.

Steven D. Brown; Maria M. Traczewski

2005-01-01

155

Effects of Antimicrobial Agents on the Milky Disease Bacteria Bacillus popilliae and Bacillus lentimorbus1  

PubMed Central

The effects of antibiotics, sulfonamides, and other antimicrobial agents on vegetative cultures of five strains of milky disease bacteria were compared with those on Bacillus subtilis Cohn emend. Prazmowski, Staphylococcus aureus Rosenbach, Sarcina lutea Schroeter, Escherichia coli (Migula) Castellani and Chalmers, Saccharomyces pastorianus Hansen, and Mucor ramannianus Moel. Similar numbers of viable cells of each organism were exposed to the test materials by use of an antibiotic-sensitivity disc method adapted from techniques recommended by the Food and Drug Administration in the Federal Register. The results suggest that vancomycin or ristocetin, as well as a few other materials, might be useful in controlling contamination either during culture of the fastidious milky disease bacteria or in large populations of vegetative cells undergoing treatment to induce sporulation. Inhibitory concentrations of vancomycin and ristocetin in shaken-tube tests were much lower than expected in comparison with results of sensitivity-disc tests on the milky disease bacteria. Sublethal concentrations of the two antibiotics elicited some morphological change in the bacteria. PMID:5866030

Pridham, T. G.; Hall, H. H.; Jackson, R. W.

1965-01-01

156

[Effect of new oral antimicrobial agents in outpatient treatment of pneumonia in children].  

PubMed

In November 2004, "Guidelines for the Management of Respiratory Infectious Diseases in Children in Japan" was published ahead of the rest of the world, by Japanese Society of Pediatric Pulmonology/Japanese Society for Pediatric Infectious Diseases, based on the data on causative organisms in the lower respiratory tract. In its 2011 version, classification of the severity of pneumonia was renewed based on the latest information. As a result, many types of pneumonia in children are now classified as mild or moderate. This means that many patients who might have conventionally required hospital treatment can now be managed on an outpatient basis. The reason for realization of the wider range of outpatient treatment is the availability of two new oral antimicrobial agents, tebipenem pivoxil and tosufloxacin tosilate hydrate, for the treatment of infections in children. Analysis of data on medical expenses shows a decreased rate of hospitalization due to pneumonia year by year after launch of these two drugs, suggesting that these drugs have contributed to wider range of outpatient treatment. This manuscript discusses the effect of tebipenem pivoxil and tosufloxacin tosilate hydrate in the treatment of pneumonia. PMID:25163249

Ouchi, Kazunobu; Sunakawa, Keisuke

2014-06-01

157

In vitro antimicrobial activity of Romanian medicinal plants hydroalcoholic extracts on planktonic and adhered cells.  

PubMed

The aim of this study was to assess the antibacterial and antifungal potential of some Romanian medicinal plants, arnica--Arnica montana, wormwood--Artemisia absinthium and nettle--Urtica dioica. In order to perform this antimicrobial screening, we obtained the vegetal extracts and we tested them on a series of Gram-positive and Gram-negative bacteria, and also against two fungal strains. The vegetal extracts showed antimicrobial activity preferentially directed against the planktonic fungal and bacterial growth, while the effect against biofilm formation and development was demonstrated only against S. aureus and C. albicans. Our in vitro assays indicate that the studied plant extracts are a significant source of natural alternatives to antimicrobial therapy, thus avoiding antibiotic therapy, the use of which has become excessive in recent years. PMID:21717806

Stanciuc, A M; Gaspar, A; Moldovan, L; Saviuc, C; Popa, M; M?ru?escu, L

2011-01-01

158

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

159

Antimicrobial constituents of foeniculum vulgare  

Microsoft Academic Search

A phenyl propanoid derivative, dillapional(1) was found to be a antimicrobial principle of the stems ofFoeniculum vulgare (Umbelliferae) with MIC values of 125, 250 and 125\\/ againstBacillus subtilis, Aspergillus niger andCladosporium cladosporioides, respectively. A cou-marin derivative, scopoletin(2) was also isolated as marginally antimicrobial agent along with inactive\\u000a compounds, dillapiol(3), bergapten(4), imperatorin(5) and psolaren(6) from this plant. The isolates 1-6 were

Yong Soo Kwon; Won Gyu Choi; Won Jun Kim; Woo Kyung cKim; Myong Jo Kim; Won Hee Kang; Chang Min Kim

2002-01-01

160

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

161

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

162

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

163

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

164

Screening of some Indian medicinal plants for their antimicrobial properties  

Microsoft Academic Search

A total of 82 Indian medicinal plants traditionally used in medicines were subjected to preliminary antibacterial screening against several pathogenic and opportunistic microorganisms. Aqueous, hexane and alcoholic extracts of each plant were tested for their antibacterial activity using agar well diffusion method at sample concentration of 200 mg\\/ml. The results indicated that out of 82 plants, 56 exhibited antibacterial activity

Iqbal Ahmad; Zafar Mehmood; Faiz Mohammad

1998-01-01

165

Ecotoxicity and screening level ecotoxicological risk assessment of five antimicrobial agents: triclosan, triclocarban, resorcinol, phenoxyethanol and p-thymol.  

PubMed

Acute and chronic (or sub-chronic) toxicity of five selected antimicrobial agents, including triclosan (TCS), triclocarban (TCC), resorcinol, phenoxyethanol and p-thymol, was investigated using the conventional three-aquatic-organism battery. These compounds are widely used in cosmetics and other personal care products and their ecological risk has recently become a significant concern. As results of toxicity tests, TCS was found to be most strongly toxic for green algae [e.g. 72?h no observed effect concentration (NOEC) of 0.50?µg?l(-1) ] among the selected compounds, followed by TCC, while TCC was more toxic or similar to TCS for Daphnia and fish (e.g. Daphnia 8?day NOEC of 1.9?µg?l(-1) ). Having compared the predicted no effect concentration (PNEC) determined from the toxicity data with measured environmental concentrations (MEC), the preliminary ecological risk assessment of these five antimicrobials was conducted. The MEC/PNEC ratios of TCS and TCC were over 1 for some monitoring data, especially in urban streams with watershed areas without sewage service coverage, and their potential risk for green algae and Daphnia might be at a level of concern, although the contribution of TCS/TCC on the total toxicity of the those sites needs to be further investigated. For the three other antimicrobials, the maximum MEC/PNEC ratio for resorcinol was 0.1-1, but those for phenoxyethanol and p-thymol were <0.1 and their risk to aquatic organisms is limited, although the additive effects with TCS, TCC and other antimicrobial agents, such as parabens, need to be further examined in future studies. Copyright © 2012 John Wiley & Sons, Ltd. PMID:22806922

Tamura, Ikumi; Kagota, Kei-Ichiro; Yasuda, Yusuke; Yoneda, Saori; Morita, Junpei; Nakada, Norihide; Kameda, Yutaka; Kimura, Kumiko; Tatarazako, Norihisa; Yamamoto, Hiroshi

2013-11-01

166

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

167

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

168

Effect of Abolishment of the Use of Antimicrobial Agents for Growth Promotion on Occurrence of Antimicrobial Resistance in Fecal Enterococci from Food Animals in Denmark  

PubMed Central

From 1995 to 2000, a total of 673 Enterococcus faecium and 1,088 Enterococcus faecalis isolates from pigs together with 856 E. faecium isolates from broilers were isolated and tested for susceptibility to four classes of antimicrobial agents used for growth promotion as part of the Danish program of monitoring for antimicrobial resistance. The four antimicrobials were avilamycin, erythromycin, vancomycin, and virginiamycin. Major changes in the use of antimicrobial agents for growth promotion have occurred during the last 6 years in Denmark. The government banned the use of avoparcin in 1995 and of virginiamycin in 1998. Furthermore, the producers have voluntarily stopped all use beginning in 1999. The avoparcin ban in 1995 was followed by a decrease in the occurrence of glycopeptide-resistant E. faecium (GRE) in broilers, from 72.7% in 1995 to 5.8% in 2000. The occurrence of glycopeptide resistance among isolates from pigs remained constant at around 20% from 1995 to 1997. It was shown that, in GRE from pigs, the genes encoding macrolide and glycopeptide resistance were genetically linked and that, following the decrease in the use of tylosin during 1998 and 1999, the occurrence of GRE in pigs decreased to 6.0% in 2000. From 1995 to 1997 the occurrence of erythromycin resistance among E. faecium and E. faecalis isolates from pigs was almost 90%. Use of tylosin decreased considerably during 1998 and 1999, and this decrease was followed by decreases in the occurrence of resistance to 46.7 and 28.1% among E. faecium and E. faecalis isolates from pigs, respectively. Erythromycin resistance among E. faecium isolates from broilers reached a maximum of 76.3% in 1997 but decreased to 12.7% in 2000 concomitantly with more limited use of virginiamycin. Use of virginiamycin increased from 1995 to 1997 and was followed by an increased occurrence of virginiamycin resistance among E. faecium isolates in broilers, from 27.3% in 1995 to 66.2% in 1997. In January 1998 the use of virginiamycin was banned in Denmark, and the occurrence of virginiamycin resistance decreased to 33.9% in 2000. Use of avilamycin increased from 1995 to 1996 and was followed by an increase in avilamycin resistance among E. faecium isolates from broilers, from 63.6% in 1995 to 77.4% in 1996. Since 1996 avilamycin usage has decreased, followed by a decrease in resistance to 4.8% in 2000. Our observations show that it is possible to reduce the occurrence of antimicrobial resistance in a national population of food animals when the selective pressure is removed. Cases in which resistance to vancomycin was linked to resistance to erythromycin were exceptions. In such cases resistance did not decrease until the use of both avoparcin and tylosin was limited. PMID:11408222

Aarestrup, Frank M?ller; Seyfarth, Anne Mette; Emborg, Hanne-Dorthe; Pedersen, Karl; Hendriksen, Rene S.; Bager, Flemming

2001-01-01

169

Effect of mixed antimicrobial agents and flavors in active packaging films.  

PubMed

Active packaging is an emerging food technology to improve the quality and safety of food products. Many works have been developed to study the antimicrobial activity of essential oils. Essential oils have been traditionally used as flavorings in food, so they have an important odor impact but they have as well antimicrobial properties that could be used to protect the food. Recent developments in antimicrobial active packaging showed the efficiency of essential oils versus bread and bakery products among other applications. However, one of the main problems to face is the odor and taste they could provide to the packaged food. Using some aromas to mask the odor could be a good approach. That is why the main objective of this paper is to develop an antimicrobial packaging material based on the combination of the most active compounds of essential oils (hydrocinnamaldehyde, oregano essential oil, cinnamaldehyde, thymol, and carvacrol) together with some aromas commonly used in the food industry. A study of the concentration required to get the antimicrobial properties, the organoleptic compatibility with typical aroma present in many food systems (vanilla, banana, and strawberry), and the right combination of both systems has been carried out. Antimicrobial tests of both the mentioned aromas, the main components of some essential oils, and the combination of both groups were carried out against bacteria (Enterococcus faecalis, Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus, Salmonella choleraesuis, Yersinia enterocolitica, Escherichia coli), yeasts (Candida albicans, Debaryomyces hansenii, Zygosaccharomyces rouxii), and molds (Botrytis cinerae, Aspergillus flavus, Penicillium roqueforti, Eurotium repens, Penicillium islandicum, Penicillium commune, Penicillium nalgiovensis). The sensory properties of the combinations were evaluated with a triangular test and classification was by an order test; the odor threshold of the aroma compounds was also studied. The results reveal that none of the aromas had antimicrobial properties. The most antimicrobial compounds are thymol, carvacrol, and cinnamaldehyde, but none of them could be combined with banana aroma, whereas only thymol with strawberry aroma gave the right combined organoleptic profile. All of the antimicrobials under study could be combined with vanilla aroma, providing both antimicrobial property and the odor expected. PMID:19711918

Gutiérrez, Laura; Escudero, Ana; Batlle, Ramón; Nerín, Cristina

2009-09-23

170

Peel bond strength of resilient liner modified by the addition of antimicrobial agents to denture base acrylic resin  

PubMed Central

In order to prolong the clinical longevity of resilient denture relining materials and reduce plaque accumulation, incorporation of antimicrobial agents into these materials has been proposed. However, this addition may affect their properties. Objective This study evaluated the effect of the addition of antimicrobial agents into one soft liner (Soft Confort, Dencril) on its peel bond strength to one denture base (QC 20, Dentsply). Material and Methods Acrylic specimens (n=9) were made (75x10x3 mm) and stored in distilled water at 37şC for 48 h. The drug powder concentrations (nystatin 500,000U - G2; nystatin 1,000,000U - G3; miconazole 125 mg - G4; miconazole 250 mg - G5; ketoconazole 100 mg - G6; ketoconazole 200 mg - G7; chlorhexidine diacetate 5% - G8; and 10% chlorhexidine diacetate - G9) were blended with the soft liner powder before the addition of the soft liner liquid. A group (G1) without any drug incorporation was used as control. Specimens (n=9) (75x10x6 mm) were plasticized according to the manufacturers' instructions and stored in distilled water at 37şC for 24 h. Relined specimens were then submitted to a 180-degree peel test at a crosshead speed of 10 mm/min. Data (MPa) were analyzed by analysis of variance (?=0.05) and the failure modes were visually classified. Results No significant difference was found among experimental groups (p=0.148). Cohesive failure located within the resilient material was predominantly observed in all tested groups. Conclusions Peel bond strength between the denture base and the modified soft liner was not affected by the addition of antimicrobial agents. PMID:23329241

ALCANTARA, Cristiane S.; de MACEDO, Allana F.C.; GURGEL, Bruno C.V.; JORGE, Janaina H.; NEPPELENBROEK, Karin H.; URBAN, Vanessa M.

2012-01-01

171

In vitro susceptibility of Haemophilus equigenitalis, the causative organism of contagious equine metritis 1977, to antimicrobial agents.  

PubMed Central

The in vitro susceptibility of recent clinical isolates of Haemophilus equigenitalis to various antimicrobial agents was determined by the disk diffusion test and the World Health Organization-International Collaborative Study agar dilution procedure. Ampicillin and tetracycline were the most active drugs. All strains were susceptible to beta-lactam antibiotics, chloramphenicol, trimethoprim-sulfamethoxazole, nalidixic acid, nitrofurantoin (Furadantin), and bacitracin. All but two strains were resistant to streptomycin, whereas all strains were susceptible to the other aminocyclitol antibodies. All strains were resistant to clindamycin, lincomycin, and metronidazole. PMID:7195184

Dabernat, H J; Delmas, C F; Tainturier, D J; Lareng, M B

1980-01-01

172

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

173

Screening of selected medicinal plants of Nepal for antimicrobial activities  

Microsoft Academic Search

In an ethnopharmacological screening of selected medicinal plants used in Nepal, methanol extracts from 21 plant species were assayed for activity against 8 strains of bacteria and 5 strains of fungi. Duplicate assays were conducted with and without exposure to UV-A radiation to test for light-activated or light-enhanced activity. All 21 of the extracts showed activity against at least 2

R. S. Taylor; N. P. Manandhar; G. H. N. Towers

1995-01-01

174

Plant antimicrobial peptides: an overview of SuperSAGE transcriptional profile and a functional review.  

PubMed

Defensin, thionin and lipid transfer protein (LTP) gene families, which antimicrobial activity has an attractive use in protein engineering and transgenic production of agronomical important plants, have been here functionally reviewed. Also, a transcriptional overview of a set of plant SuperSAGE libraries and analysis looking for 26 bp tags possibly annotated for those families is presented. Tags differentially expressed (p = 0.05) or constitutively transcribed were identified from leaves or roots SuperSAGE libraries from important Brazilian plant species [cowpea (Vigna unguiculata (L.) Walp.), soybean (Glycine max (L.) Merr.) and modern sugarcane hybrids (Saccharum spp.)] submitted to abiotic [salt (100 mM NaCl) or drought] or biotic stresses [fungus inoculation (Phakopsora pachyrhizi; Asiatic Soyben Rust phytopathogen)]. The diverse transcriptional patterns observed, probably related to the variable range of targets and functions involved, could be the first step to unravel the antimicrobial peptide world and the plant stress response relationship. Moreover, SuperSAGE opens the opportunity to find some SNPs or even rare transcript that could be important on plant stress resistance mechanisms. Putative defensin or LTP identified by SuperSAGE following a specific plant treatment or physiological condition could be useful for future use in genetic improvement of plants. PMID:20088771

Kido, E A; Pandolfi, V; Houllou-Kido, L M; Andrade, P P; Marcelino, F C; Nepomuceno, A L; Abdelnoor, R V; Burnquist, W L; Benko-Iseppon, A M

2010-05-01

175

Synthesis of antimicrobial silver nanoparticles by callus and leaf extracts from saltmarsh plant, Sesuvium portulacastrum L  

Microsoft Academic Search

The present work studied the effect of extracts from tissue culture-derived callus and leaf of the saltmarsh plant, Sesuvium portulacastrum L. on synthesis of antimicrobial silver nanoparticles using AgNO3 as a substrate. The callus extract could be able to produce silver nanoparticles, better than leaf extract. The synthesis of silver nanoparticles was confirmed with X-ray diffraction spectrum which exhibited intense

Asmathunisha Nabikhan; Kathiresan Kandasamy; Anburaj Raj; Nabeel M. Alikunhi

2010-01-01

176

Antimicrobial evaluation of certain plants used in Mexican traditional medicine for the treatment of respiratory diseases  

Microsoft Academic Search

Eighteen crude extracts, including six hexanic, six chloroformic and six methanolic from six different plant species used in Mexican traditional medicine for the treatment of respiratory infections, were evaluated for potential antimicrobial activity against Staphylococcus aureus,Enterococcus faecalis,Streptococcus pneumoniae, Streptococcus pyogenes, Escherichia coli, and Candida albicans. The minimal inhibitory concentration was determined for each extract using a two-fold dilution assay. The

Gabriela Rojas; Juan Lévaro; Jaime Tortoriello; Victor Navarro

2001-01-01

177

Screening of plant Macaranga peltata for its antioxidant, antimicrobial and cytotoxicity activity  

Microsoft Academic Search

The plant Macaranga peltata (Euphorbiaceae) leaves and stem bark was tested for its in vitro antioxidant, antimicrobial and cytotoxicity activity using different methods. In vitro anti oxidant activity stem bark extract showed inhibitory concentration 50% (IC50) value of 10.13 than the leaf extract IC50 = 14.85 for DPPH assay. Standard ascorbic acid showed IC50 = 7.28. For ABTS free radical

Meenakshi Verma; P. V. Raj; H. R. Chandrasekhar; J. V. Rao; N. Udupa

2009-01-01

178

Antimicrobial activities of extracts from Indo-Pacific marine plants against marine pathogens and saprophytes  

Microsoft Academic Search

This study is the second of two surveys designed to systematically screen extracts from marine plants for antimicrobial effects\\u000a against ecologically relevant marine microorganisms, and to compare results on a geographical basis. In the preceding survey,\\u000a extracts from tropical Atlantic marine algae and seagrasses were screened in growth inhibition assays against the pathogenic\\u000a fungus Lindra thalassiae, the saprophytic fungus Dendryphiella

Melany P. Puglisi; Sebastian Engel; Paul R. Jensen; William Fenical

2007-01-01

179

Cefotetan: a second-generation cephalosporin active against anaerobic bacteria. Committee on Antimicrobial Agents, Canadian Infectious Disease Society.  

PubMed Central

OBJECTIVE: To offer guidelines for the use of cefotetan, a cephamycin antibiotic, in order to minimize its overprescription. OPTIONS: Clinical practice options considered were treatment of infections with the use of second- and third-generation cephalosporins, carbapenems such as imipenem as well as combination regimens of agents active against anaerobic bacteria, such as metronidazole or clindamycin with an aminoglycoside. OUTCOMES: In order of importance: efficacy, side effects and cost. EVIDENCE: A MEDLINE search of articles published between January 1982 and December 1993. In-vitro and pharmacokinetic studies published in recognized peer-reviewed journals that used recognized standard methods with appropriate controls were reviewed. For results of clinical trials, the reviewers emphasized randomized double-blind trials with appropriate controls. VALUES: The Antimicrobial Agents Committee of the Canadian Infectious Disease Society (CIDS) and a recognized expert (M.J.G.) recommended use of cefotetan to prevent and treat infections against which it has proved effective in randomized controlled trials. BENEFITS, HARMS AND COSTS: These guidelines should lead to less inappropriate prescribing of cefotetan, with its attendant costs and risk of development of resistant bacteria. RECOMMENDATIONS: Cefotetan could be considered an alternative single agent for prophylaxis of infection in patients undergoing elective bowel surgery. It may be used to treat patients with acute pelvic inflammatory disease and endometritis. VALIDATION: This article was prepared, reviewed and revised by the Committee on Antimicrobial Agents of the CIDS. It was then reviewed by the Council of the CIDS, and any further necessary revisions were made by the chairman of the committee. PMID:8069799

Gribble, M J

1994-01-01

180

Biphasic toxicodynamic features of some antimicrobial agents on microbial growth: a dynamic mathematical model and its implications on hormesis  

PubMed Central

Background In the present work, we describe a group of anomalous dose-response (DR) profiles and develop a dynamic model that is able to explain them. Responses were obtained from conventional assays of three antimicrobial agents (nisin, pediocin and phenol) against two microorganisms (Carnobacterium piscicola and Leuconostoc mesenteroides). Results Some of these anomalous profiles show biphasic trends which are usually attributed to hormetic responses. But they can also be explained as the result of the time-course of the response from a microbial population with a bimodal distribution of sensitivity to an effector, and there is evidence suggesting this last origin. In light of interest in the hormetic phenomenology and the possibility of confusing it with other phenomena, especially in the bioassay of complex materials we try to define some criteria which allow us to distinguish between sensu stricto hormesis and biphasic responses due to other causes. Finally, we discuss some problems concerning the metric of the dose in connection with the exposure time, and we make a cautionary suggestion about the use of bacteriocins as antimicrobial agents. Conclusions The mathematical model proposed, which combines the basis of DR theory with microbial growth kinetics, can generate and explain all types of anomalous experimental profiles. These profiles could also be described in a simpler way by means of bisigmoidal equations. Such equations could be successfully used in a microbiology and toxicology context to discriminate between hormesis and other biphasic phenomena. PMID:20723220

2010-01-01

181

In vitro culture system to determine MICs and MBCs of antimicrobial agents against Treponema pallidum subsp. pallidum (Nichols strain).  

PubMed

A new procedure for determining the susceptibility of Treponema pallidum subsp. pallidum to antimicrobial agents was developed, utilizing a tissue culture system which promotes the in vitro multiplication of this organism. In the absence of antibiotics, T. pallidum (Nichols virulent strain) multiplied an average of 10-fold when incubated for 7 days in the presence of Sf1Ep cottontail rabbit epithelial cell cultures. Varied concentrations of penicillin G, tetracycline, erythromycin, and spectinomycin were added to triplicate cultures to determine their effects on treponemal multiplication, motility, and virulence. The MIC of each antibiotic was defined as the lowest concentration which prevented treponemal multiplication, whereas the MBC was defined as the lowest concentration which abrogated the ability of the cultured treponemes to multiply and cause lesions in rabbits. The in vitro culture technique provided highly reproducible MICs and (in parentheses) MBCs of each of the antibiotics tested: aqueous penicillin G, 0.0005 (0.0025) microgram/ml; tetracycline, 0.2 (0.5) microgram/ml; erythromycin, 0.005 (0.005) microgram/ml; and spectinomycin, 0.5 (0.5) microgram/ml. The significance of these results in light of the in vivo activities and the previous in vitro evaluations of these antibiotics is discussed. The T. pallidum in vitro cultivation system shows promise as a method for studying the interaction between T. pallidum and antimicrobial agents and for screening new antibiotics for syphilis therapy. PMID:2964810

Norris, S J; Edmondson, D G

1988-01-01

182

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

Microsoft Academic Search

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

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

2010-01-01

183

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

184

Aspirin inhibits the growth of Helicobacter pylori and enhances its susceptibility to antimicrobial agents  

Microsoft Academic Search

Background and aim: The role of Helicobacter pylori and aspirin in peptic ulcer formation and recurrence remains an important clinical topic. The interaction between aspirin and H pylori in vitro is also not clear. We investigated the effect of aspirin on the growth of H pylori and on the susceptibility of H pylori to antimicrobials. Methods: Time killing studies of

BCY Wong

2007-01-01

185

Green synthesis and biological evaluation of some novel azoles as antimicrobial agents.  

PubMed

A series of novel fluorine-containing triazoles 3, thiadiazoles 4, and oxadiazoles 5 were synthesized from thiosemicarbazides 2. These reactions were carried out by green technique such as ultrasonication and microwave. All products have been characterized by IR, (1)H NMR, and Mass spectral study and screened for their antimicrobial activity. PMID:21074427

Shelke, Sharad; Mhaske, Ganesh; Gadakh, Sunil; Gill, Charnsingh

2010-12-15

186

Synthesis of some novel 4-arylidene pyrazoles as potential antimicrobial agents  

PubMed Central

Background Pyrazole and pyrazolone motifs are well known for their wide range of biological activities such as antimicrobial, anti-inflammatory, and antitumor activities. The incorporation of more than one pharmacophore in a single scaffold is a well known approach for the development of more potent drugs. In the present investigation, a series of differently substituted 4-arylidene pyrazole derivatives bearing pyrazole and pyrazolone pharmacophores in a single scaffold was synthesized. Results The synthesis of novel 4-arylidene pyrazole compounds is achieved through Knovenagel condensation between 1,3-diaryl-4-formylpyrazoles and 3-methyl-1-phenyl-1H-pyrazol-5-(4H)-ones in good yields. All compounds were evaluated for their in vitro antimicrobial activity. Conclusions A series of 4-arylidene pyrazole derivatives was evaluated for their in vitro antimicrobial activity against two Gram-positive (Bacillus subtilis and Staphylococcus aureus) and two Gram-negative bacteria (Pseudomonas fluorescens and Escherichia coli), as well as two pathogenic fungal strains (Candida albicans and Saccharomyces cerevisiae). The majority of the compounds displayed excellent antimicrobial profile against the Gram-positive (B. subtilis and S. aureus), and some of them are even more potent than the reference drug ciprofloxacin. PMID:23981685

2013-01-01

187

Edible apple film wraps containing plant antimicrobials inactivate foodborne pathogens on meat and poultry products.  

PubMed

Apple-based edible films containing plant antimicrobials were evaluated for their activity against pathogenic bacteria on meat and poultry products. Salmonella enterica or E. coli O157:H7 (10(7) CFU/g) cultures were surface inoculated on chicken breasts and Listeria monocytogenes (10(6) CFU/g) on ham. The inoculated products were then wrapped with edible films containing 3 concentrations (0.5%, 1.5%, and 3%) of cinnamaldehyde or carvacrol. Following incubation at either 23 or 4 degrees C for 72 h, samples were stomached in buffered peptone water, diluted, and plated for enumeration of survivors. The antimicrobial films exhibited concentration-dependent activities against the pathogens tested. At 23 degrees C on chicken breasts, films with 3% antimicrobials showed the highest reductions (4.3 to 6.8 log CFU/g) of both S. enterica and E. coli O157:H7. Films with 1.5% and 0.5% antimicrobials showed 2.4 to 4.3 and 1.6 to 2.8 log reductions, respectively. At 4 degrees C, carvacrol exhibited greater activity than did cinnamaldehyde. Films with 3%, 1.5%, and 0.5% carvacrol reduced the bacterial populations by about 3, 1.6 to 3, and 0.8 to 1 logs, respectively. Films with 3% and 1.5% cinnamaldehyde induced 1.2 to 2.8 and 1.2 to 1.3 log reductions, respectively. For L. monocytogenes on ham, carvacrol films induced greater reductions than did cinnamaldehyde films at all concentrations tested. In general, the reduction of L. monocytogenes on ham at 23 degrees C was greater than at 4 degrees C. Added antimicrobials had minor effects on physical properties of the films. The results suggest that the food industry and consumers could use these films as wrappings to control surface contamination by foodborne pathogenic microorganisms. PMID:19799671

Ravishankar, Sadhana; Zhu, Libin; Olsen, Carl W; McHugh, Tara H; Friedman, Mendel

2009-10-01

188

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

189

Phytochemical composition and in vitro antimicrobial and antioxidant activities of some medicinal plants.  

PubMed

Different parts of three plants (Primula auriculata, Fumaria vaillantii and Falcaria vulgaris) were extracted with three different solvents to yield 72 crude extracts. The phytochemical analysis (chemical screening, GC-MS) of three plants was investigated for their antioxidant and antibacterial activity using nine Gram-positive and Gram-negative bacteria. The principal antioxidant and antimicrobial components were determined using HPLC with UV detection. All extracts possessed antibacterial activity especially methanolic extracts from flowers of P. auriculata. The DPPH-radical scavenging assay exhibited high antioxidant activities in three plants (more than 80% at 50?g). The F. vulgaris showed high content of carvacrol (29.8%) as main component. The contents of carvacrol and fumaric acid in the methanolic-water extracts were 1119 and 1966mg/l respectively. Our results indicate that these plants would be able to promise sources of natural products with potential antibacterial and antioxidant activity. PMID:23017418

Jaberian, Hamideh; Piri, Khosro; Nazari, Javad

2013-01-01

190

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

191

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

Microsoft Academic Search

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

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

2012-01-01

192

Potentially active antimicrobial agents from 2-benzenesulfonyloxyphenyl-3,1-benzoxazine-4-one derivative.  

PubMed

Fourteen of nitrogeneous heterocyclic compounds that accommodate the sulfonate-ester moiety were synthesized through interaction of 2-benzenesulfonylo xyphenyl-3,1-benzoxazine-4-one with some nucleophilic reagents. The assigned structures for the prepared new compounds were confirmed on the basis of elemental and spectral data. Evaluation of the antimicrobial activity of these products, relative to standard antibiotics was tested and discussed. PMID:8527103

Habib, O M; Moawad, E B; Girges, M M; el-Shafei, A M

1995-10-01

193

Light insensitive silver(I) cyanoximates as antimicrobial agents for indwelling medical devices.  

PubMed

Ten silver(I) cyanoximates of AgL composition (L = NC-C(NO)-R, where R is electron withdrawing groups: -CN, -C(O)NR(2), -C(O)R' (alkyl), -C(O)OEt, 2-heteroaryl fragments such as 2-pyridyl, 2-benzimidazolyl, 2-benzoxazolyl, 2-benzthiazolyl) were synthesized and characterized using spectroscopic methods and X-ray analysis. Crystal structures of four complexes were determined and revealed the formation of two-dimensional (2D) coordination polymers of different complexity in which anions exhibit bridging or combined chelate and bridging binding modes. In these compounds, anions are in the nitroso form. All studied AgL complexes are sparingly soluble in water and are thermally stable to 150 °C. Synthesized compounds demonstrated remarkable insensitivity toward visible light and UV-radiation, which was explained based on their polymeric structures with multiple covalent bonds between bridging cyanoxime ligands and Ag(I) centers. All 10 silver(I) cyanoximates were tested in vitro on the subject of their antimicrobial activity against both Gram-positive and Gram-negative microorganisms such as Escherichia coli, Klebsiella pneumoniae, Proteus sp., Pseudomonas aeruginosa, Enterococcus hirae, Streptococcus mutans, Staphylococcus aureus, and Mycobacterium fortuitum as well as against Candida albicans in solutions, and in the solid state as pressed pellets and dried filter paper disks presoaked with solutions of AgL in DMF. Results showed pronounced antimicrobial activity for all investigated complexes. A combination of five factors: (1) light insensitivity, (2) poor water solubility, (3) high thermal stability, (4) lack of toxicity of organic ligands, and (5) in vitro antimicrobial activity allows development of silver(I) cyanoximates for medical applications. These include antimicrobial additives to acrylate glue, cured by UV-radiation, used in introduction of prosthetic joints and dental implants, and prevention of biofilm formation on several types of indwelling medical devices. PMID:20873734

Gerasimchuk, Nikolay; Gamian, Andrzej; Glover, Garrett; Szponar, Bogumila

2010-11-01

194

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

195

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.; Hernandez Iturriaga, Montserrat

2014-01-01

196

A novel antimicrobial protein for plant protection consisting of a Xanthomonas oryzae harpin and active domains of cecropin A and melittin  

PubMed Central

Summary Discoveries about antimicrobial peptides and plant defence activators have made possible the de novo and rational design of novel peptides for use in crop protection. Here we report a novel chimeric protein, Hcm1, which was made by linking the active domains of cecropin A and melittin to the hypersensitive response (HR)?elicitor Hpa1 of Xanthomonas oryzae pv. oryzicola, the causal agent of rice bacterial leaf streak. The resulting chimeric protein maintained not only the HR?inducing property of the harpin, but also the antimicrobial activity of the cecropin A?melittin hybrid. Hcm1 was purified from engineered Escherichia coli and evaluated in terms of the minimal inhibitory concentration (MIC) and the 50% effective dose (ED50) against important plant pathogenic bacteria and fungi. Importantly, the protein acted as a potential pesticide by inducing disease resistance for viral, bacterial and fungal pathogens. This designed drug can be considered as a lead compound for use in plant protection, either for the development of new broad?spectrum pesticides or for expression in transgenic plants. PMID:21895994

Che, Yi-Zhou; Li, Yu-Rong; Zou, Hua-Song; Zou, Li-Fang; Zhang, Bing; Chen, Gong-You

2011-01-01

197

Studies of the in vitro anticancer, antimicrobial and antioxidant potentials of selected Yemeni medicinal plants from the island Soqotra  

Microsoft Academic Search

BACKGROUND: Recent years have witnessed that there is a revival of interest in drug discovery from medicinal plants for the maintenance of health in all parts of the world. The aim of this work was to investigate 26 plants belonging to 17 families collected from a unique place in Yemen (Soqotra Island) for their in vitro anticancer, antimicrobial and antioxidant

Ramzi A Mothana; Ulrike Lindequist; Renate Gruenert; Patrick J Bednarski

2009-01-01

198

ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, Nov. 2007, p. 41254132 Vol. 51, No. 11 0066-4804/07/$08.00 0 doi:10.1128/AAC.00208-07  

E-print Network

of this compound against S. mutans growing under conditions that favor biofilm formation. Our results indicate. Activity of an Antimicrobial Peptide Mimetic against Planktonic and Biofilm Cultures of Oral Pathogens of bacterial and Candida species found in oral infections. Since Streptococcus mutans, an etiological agent

Tew, Gregory N.

199

Medicinal plants as immunosuppressive agents in traditional Iranian medicine.  

PubMed

Immunomodulation using medicinal plants provides an alternative to conventional chemotherapy for several diseases, especially when suppression of inflammation is desired. The "Canon of Medicine", the epochal work of Avicenna, the great Persian scientist of the middle ages, provides comprehensive information about medicinal plants which used to cure inflammatory illnesses in traditional Iranian medicine. Taking into consideration that the mechanisms of damage in these illnesses are mediated by immune responses, it is reasonable to assume that the plants used for such diseases may suppress the immune responses and the resultant inflammation. In Iran, because of great diversity of climate and geographical conditions, numerous varieties of plants grow and at least 1000 species are recorded as medicinal plants. Many of these plants such as Punica granatum, Glycyrrhiza glabra, Foeniculum vulgare and Polygonum species prescribed by ancient Iranian physicians have been shown to possess anti-inflammatory and immunomodulatory effects. In recent literature, different species of native medicinal plants such as Stachys obtusicrena, Salvia mirzayanii, Echium amoenum, Dracocephalum kotschyi and Linum persicum have been shown to have appreciable anti-inflammatory and immunomodulatory effects including inhibitory effects on lymphocyte activation, suppression of cellular and humoral immunity and induction of apoptosis. This review focuses on plants that are used in Iranian traditional medicine and have been reported to act as immunoinhibitory agents. PMID:20574119

Amirghofran, Zahra

2010-06-01

200

Antimicrobial effects of Finnish plant extracts containing flavonoids and other phenolic compounds.  

PubMed

Plant phenolics, especially dietary flavonoids, are currently of growing interest owing to their supposed functional properties in promoting human health. Antimicrobial screening of 13 phenolic substances and 29 extracts prepared from Finnish plant materials against selected microbes was conducted in this study. The tests were carried out using diffusion methods with four to nine microbial species (Aspergillus niger, Bacillus subtilis, Candida albicans, Escherichia coli, Micrococcus luteus, Pseudomonas aeruginosa, Saccharomyces cerevisiae, Staphylococcus aureus and Staphylococcus epidermidis). Flavone, quercetin and naringenin were effective in inhibiting the growth of the organisms. The most active plant extracts were purple loosestrife (Lythrum salicaria L.) against Candida albicans, meadowsweet (Filipendula ulmaria (L.) Maxim.), willow herb (Epilobium angustifolium L.), cloudberry (Rubus chamaemorus L.) and raspberry (Rubus idaeus L.) against bacteria, and white birch (Betula pubescens Ehrh.), pine (Pinus sylvestris L.) and potato (Solanum tuberosum. L.) against gram-positive Staphylococcus aureus. PMID:10857921

Rauha, J P; Remes, S; Heinonen, M; Hopia, A; Kähkönen, M; Kujala, T; Pihlaja, K; Vuorela, H; Vuorela, P

2000-05-25

201

Which approach is more effective in the selection of plants with antimicrobial activity?  

PubMed

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

202

Antimicrobial activity of extracts from in vivo and in vitro propagated Lamium album L. plants.  

PubMed

The antimicrobial activity of 18 different extracts from in vivo and in vitro grown L. album L. plants was evaluated against clinical bacteria and yeasts using the well diffusion method. All the used extracts demonstrated antibacterial activity, whereas only the water extracts from leaves (in vivo) possessed antifungal activity against Candida albicans NBIMCC 72 and Candida glabrata NBIMCC 8673 (14 and 20 mm diameter of inhibition zones and MIC 10 mg/ml, respectively). The methanol and ethanol extracts obtained from the in vitro propagated plants had a broader spectrum of antibacterial activity than those from in vivo plants, while the opposite tendency was observed for the chloroform extracts. All tested flower extracts possessed antimicrobial activity. The chloroform extract from in vivo flowers demonstrated the highest activity against E. faecalis NBIMCC 3915, S. aureus NBIMCC 3703, P. hauseri NBIMCC 1339 and P. aeruginosa NBIMCC 3700 (22 mm, 13 mm, 11 mm, 23 mm zone diameter of inhibition and MIC 0.313 mg/ml, respectively). The water extracts from leaves (both in vivo and in vitro) possessed higher antibacterial activity than extract from flowers. The obtained results showed that both in vivo and in vitro propagated L. album L. could be used as a source of antibacterial substances. PMID:24311888

Chipeva, Valentina Aleksandrova; Petrova, Detelina Christova; Geneva, Milena Evgenieva; Dimitrova, Milena Angelova; Moncheva, Penka Angelova; Kapchina-Toteva, Veneta Michova

2013-01-01

203

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 Lucia Cavalcanti; Albuquerque, Ulysses Paulino

2013-01-01

204

Preliminary Screening of Endophytic Fungi from Medicinal Plants in Malaysia for Antimicrobial and Antitumor Activity  

PubMed Central

The screening of antimicrobial activity against Gram-positive bacteria, Gram-negative bacteria, yeast and fungi was carried out on isopropanol extracts prepared from 121 isolates of endophytic fungi isolated from medicinal plants in Malaysia. Sensitivity was found to vary among the microorganisms. Bacillus subtilis, Saccharomyces cerevisiae and Alternaria sp. were susceptible to extracts from three, two and two isolates of endophytic fungi, respectively. None were found effective against Salmonella typhimurium. Sixteen endophytic fungal isolates tested were also found to exhibit antitumor activity in the yeast cell-based assay. PMID:22844221

Radu, Son; Kqueen, Cheah Yoke

2002-01-01

205

A novel microfluidic wound model for testing antimicrobial agents against Staphylococcus pseudintermedius biofilms  

PubMed Central

Background Current methods for testing treatments for veterinary surgical site infections can successfully emulate elements of a chronic wound, but these are time consuming and costly, requiring specialized laboratory equipment and considerable space to house study animals. Microfluidic devices however, can be coated with collagen and maintained at basal body temperature, providing a more cost-effective and space-saving model of a chronic wound. Our study assesses the applicability of a new microfluidic model by testing the activity of DispersinB against biofilms of methicillin-resistant Staphylococcus pseudintermedius (MRSP); DispersinB has been shown to prevent biofilm growth of Staphylococcus epidermidis, another prominent wound colonizer. Results We successfully developed a microfluidic model to examine the effects of antimicrobial therapy on biofilms formed by organisms associated with wound infections in companion animals (e.g. MRSP). Although, we were unable to recapitulate previous findings that DispersinB-Gentamycin is highly effective against Staphylococcal biofilms using this model, we were able to confirm its effect in a microtitre plate. Differences in the experimental conditions likely account for this result (e.g. strains tested, flow conditions, treatment time, etc.). In the microtitre plate assay, DispersinB inhibited biofilm growth after a 24 hour period; there was an inverse relationship between the concentration of DispersinB-Gentamycin and the amount of biofilm remaining following treatment. Collagen-coated microtitre plates showed a similar result, but this did not correlate as well; collagen, the most abundant protein in the body may help to retain the biomass of treated biofilms. Conclusions Our model may be useful in examining the effect of treatment on wound infections, although we acknowledge that in this model the test organisms may be more recalcitrant to antimicrobials than in other published systems. We contend that this may in fact better represent the conditions in vivo, where organisms associated with chronic wound infections are highly resistant to antimicrobials. PMID:24411017

2014-01-01

206

Functional Gold Nanoparticles as Potent Antimicrobial Agents against Multi-Drug-Resistant Bacteria.  

PubMed

We present the use of functionalized gold nanoparticles (AuNPs) to combat multi-drug-resistant pathogenic bacteria. Tuning of the functional groups on the nanoparticle surface provided gold nanoparticles that were effective against both Gram-negative and Gram-positive uropathogens, including multi-drug-resistant pathogens. These AuNPs exhibited low toxicity to mammalian cells, and bacterial resistance was not observed after 20 generations. A strong structure-activity relationship was observed as a function of AuNP functionality, providing guidance to activity prediction and rational design of effective antimicrobial nanoparticles. PMID:25232643

Li, Xiaoning; Robinson, Sandra M; Gupta, Akash; Saha, Krishnendu; Jiang, Ziwen; Moyano, Daniel F; Sahar, Ali; Riley, Margaret A; Rotello, Vincent M

2014-10-28

207

Design and synthesis of spiro[indole-thiazolidine]spiro[indole-pyrans] as antimicrobial agents  

Microsoft Academic Search

A series of novel spiro[indole-thiazolidine]spiro[indole-pyran] derivatives were synthesized from N-(bromoalkyl)indol-2,3-diones via monospiro-bisindole intermediates; the two indole nuclei being connected via N–(CH2)n–N linker. Synthesized compounds were evaluated for their antimicrobial activities in vitro against three Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, and Staphylococcus epidermis), four Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, and Klebsiella pneumonia) as well as four fungi

Rajeev Sakhuja; Siva S. Panda; Leena Khanna; Shilpi Khurana; Subhash C. Jain

2011-01-01

208

Metabolomics Reveals the Origins of Antimicrobial Plant Resins Collected by Honey Bees  

PubMed Central

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

209

Thermal solvent-free synthesis of novel pyrazolyl chalcones and pyrazolines as potential antimicrobial agents.  

PubMed

A novel approach was adopted for the synthesis of series of new pyrazolyl chalcones (3a-c) by the reaction of 5-chloro-3-methyl-1-phenylpyrazole-4-carboxaldehyde (1) with different 5-acetylbarbituric acid derivatives (2a-c) under thermal solvent-free condition. The chalcones were then converted to the corresponding pyrazolines (4a-c) under the same condition in excellent yields. All the synthesized compounds were characterized using elemental analysis and spectral data (IR, (1)H NMR, and mass spectrometry). The synthesized compounds were tested for their antimicrobial activity by disk diffusion assay with slight modifications against Gram-positive, Gram-negative strains of bacteria as well as fungal strains. The investigation of antimicrobial screening revealed that compounds (3a-4c) showed good antibacterial and antifungal activities, respectively. Among the screened compounds, 3b showed more potent inhibitory activity (MIC=12.5 ?g/ml) nearly to that of standard antibiotics ciprofloxacin, griseofulvin and fluconazole. PMID:21507638

Siddiqui, Zeba N; Musthafa, T N Mohammed; Ahmad, Anis; Khan, Asad U

2011-05-15

210

Design of potent, non-toxic antimicrobial agents based upon the structure of the frog skin peptide, temporin-1CEb from Chinese brown frog, Rana chensinensis.  

PubMed

Temporin-1CEb shows antimicrobial activity against Gram-positive bacteria, but its therapeutic potential is limited by its haemolysis. In this study, eight temporin-1CEb analogues with altered cationicities and hydrophobicities were synthesized. Increasing cationicity and amphipathicity by substituting neutral and non-polar amino acid residues on the hydrophilic face of the ?-helix by five or six lysines increased antimicrobial potency approximately 10-fold to 40-fold, although when the number of positive charges was increased from +6 to +7, the antimicrobial potency was not additionally enhanced. The substitution of an l-lysine with a d-lysine, meanwhile maintaining the net charge and the mean hydrophobicity values, had only a minor effect on its antimicrobial activity, whereas significantly led a decrease in its haemolytic activity. Of all the peptides, l-K6 has the best potential as an antimicrobial agent because its antimicrobial activity against both Gram-positive and Gram-negative bacteria is substantial, and its haemolytic activity is negligible. l-K6 adopts an ?-helix in 50% trifluoroethanol/water and 30?mm SDS solutions. l-K6 killed 99.9% of E. coli and S. aureus at 4× MIC in 60?min, and its postantibiotic effect was >5?h. l-K6 affects the integrity of E. coli and S. aureus plasma membranes by rapidly inducing membrane depolarization. PMID:22348663

Shang, Dejing; Li, Xiaofan; Sun, Yue; Wang, Che; Sun, Li; Wei, Shi; Gou, Meng

2012-05-01

211

Antimicrobial volatile organic compounds affect morphogenesis-related enzymes in Guignardia citricarpa, causal agent of citrus black spot  

Microsoft Academic Search

Although non-volatile substances toxic to plant pathogenic microorganisms have been extensively studied over the years, few studies have focused on microbial volatile organic compounds (VOCs). The VOCs produced by the yeast Saccharomyces cerevisiae strain CR-1, used in fermentative processes for fuel ethanol production, are able to inhibit the vegetative development of the fungus Guignardiacitricarpa, causal agent of the disease citrus

Mauricio Batista Fialho; Luiz Fernando Romanholo Ferreira; Regina Teresa Rosim Monteiro; Sérgio Florentino Pascholati

2010-01-01

212

Antimicrobial volatile organic compounds affect morphogenesis-related enzymes in Guignardia citricarpa, causal agent of citrus black spot  

Microsoft Academic Search

Although non-volatile substances toxic to plant pathogenic microorganisms have been extensively studied over the years, few studies have focused on microbial volatile organic compounds (VOCs). The VOCs produced by the yeast Saccharomyces cerevisiae strain CR-1, used in fermentative processes for fuel ethanol production, are able to inhibit the vegetative development of the fungus Guignardiacitricarpa, causal agent of the disease citrus

Mauricio Batista Fialho; Luiz Fernando Romanholo Ferreira; Regina Teresa Rosim Monteiro; Sérgio Florentino Pascholati

2011-01-01

213

A Study on the Usage Pattern of Antimicrobial Agents for the Prevention of Surgical Site Infections (SSIs) in a Tertiary Care Teaching Hospital  

PubMed Central

Context: Inappropriate antimicrobial use increases the incidence of drug resistance, drug toxicity and superinfections, thereby increasing the healthcare costs. Various approaches for rationalizing the antimicrobial therapy, have been suggested. Collection of baseline data on the pattern of the antimicrobial use is usually suggested as the first step in this direction, which will help in identifying the problem areas, which demand our attention. Aims: To study the usage pattern of prophylactic antimicrobials in surgical patients, in order to detect any inappropriateness concerning the selection, timing, redosing and the duration of antimicrobial administration. Settings and Design: A retrospective review of the randomly selected medical records of general surgical cases over an 8 month period in a tertiary care teaching hospital. Methods and Material: The medical records of 258 patients who had undergone surgical procedures were verified for the appropriateness of the antimicrobial prophylaxis, with respect to the choice of the antimicrobial agent, the time of its administration, the intraoperative dosing, and the duration of the postoperative use. The obtained data was analyzed and conclusions were drawn with the help of descriptive statistics. Results: Third generation cephalosporins were used preoperatively in all the 258(100%) patients through the intravenous route. In addition, 77(30%) patients received metronidazole or amikacin. The antimicrobials were administered half an hour to one hour before the surgery. No intraoperative redosing was given. The duration of the postoperative prophylaxis was extended to 36 hours or more in 248(96%) of the cases. Conclusions: The timing of administration of the preoperative dose was appropriate and well delegated to the operating room nurse. The intra operative dose was appropriately omitted. The main concern was the increasing use of the third generation cephalosporins and the unnecessary prolonged duration of the postoperative prophylaxis, which needed to be addressed. PMID:23730643

Khan A.K, Afzal; P.V, Mirshad; Rashed, Mohammed Rafiuddin; Banu, Gausia

2013-01-01

214

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

215

Synthesis and evaluation of a class of new coumarin triazole derivatives as potential antimicrobial agents.  

PubMed

A series of new coumarin-based 1,2,4-triazole derivatives were designed, synthesized and evaluated for their antimicrobial activities in vitro against four Gram-positive bacteria (Staphylococcus aureus, MRSA, Bacillus subtilis and Micrococcus luteus), four Gram-negative bacteria (Escherichia coli, Proteus vulgaris, Salmonella typhi and Shigella dysenteriae) as well as three fungi (Candida albicans, Saccharomyces cerevisiae and Aspergillus fumigatus) by two-fold serial dilution technique. The bioactive assay showed that some synthesized coumarin triazoles displayed comparable or even better antibacterial and antifungal efficacy in comparison with reference drugs Enoxacin, Chloromycin and Fluconazole. Coumarin bis-triazole compounds exhibited stronger antibacterial and antifungal efficiency than their corresponding mono-triazole derivatives. PMID:21215620

Shi, Yuan; Zhou, Cheng-He

2011-02-01

216

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

PubMed

Abstract 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, Erika 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

217

Design and synthesis of spiro[indole-thiazolidine]spiro[indole-pyrans] as antimicrobial agents.  

PubMed

A series of novel spiro[indole-thiazolidine]spiro[indole-pyran] derivatives were synthesized from N-(bromoalkyl)indol-2,3-diones via monospiro-bisindole intermediates; the two indole nuclei being connected via N-(CH(2))(n)-N linker. Synthesized compounds were evaluated for their antimicrobial activities in vitro against three Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, and Staphylococcus epidermis), four Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, and Klebsiella pneumonia) as well as four fungi (Aspergillus niger, Aspergillus fumigatus, Aspergillus flavus, and Candida albicans) using Cup plate method. Bis spiro-indoles exhibited stronger antibacterial and antifungal efficiency than their corresponding mono spiro-indoles. Compound 10e, the most active derivative was shown to inhibit the growth of all bacterial strains and two fungal strains (A. niger and C. albicans). PMID:21782421

Sakhuja, Rajeev; Panda, Siva S; Khanna, Leena; Khurana, Shilpi; Jain, Subhash C

2011-09-15

218

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

PubMed

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

219

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

220

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

221

Modulation of plant ion channels by oxidizing and reducing agents.  

PubMed

Ion channels are proteins forming hydrophilic pathways through the membranes of all living organisms. They play important roles in the electrogenic transport of ions and metabolites. Because of biophysical properties such as high selectivity for the permeant ion, high turnover rate, and modulation by physico-chemical parameters (e.g., membrane potential, calcium concentration), they are involved in several physiological processes in plant cells (e.g., maintenance of the turgor pressure, stomatal movements, and nutrient absorption by the roots). As plants cannot move, plant metabolism must be flexible and dynamic, to cope with environmental changes, to compete with other living species and to prevent pathogen invasion. An example of this flexibility and dynamic behavior is represented by their handling of the so-called reactive oxygen species, inevitable by-products of aerobic metabolism. Plants cope with these species on one side avoiding their toxic effects, on the other utilizing them as signalling molecules and as a means of defence against pathogens. In this review, we present the state-of-the-art of the modulation of plant ion channels by oxidizing and reducing agents. PMID:15629107

Scholz-Starke, J; Gambale, F; Carpaneto, A

2005-02-01

222

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

223

Screening for antimicrobial activity of ten medicinal plants used in Colombian folkloric medicine: A possible alternative in the treatment of non-nosocomial infections  

PubMed Central

Background The antimicrobial activity and Minimal Inhibitory Concentration (MIC) of the extracts of Bidens pilosa L., Bixa orellana L., Cecropia peltata L., Cinchona officinalis L., Gliricidia sepium H.B. & K, Jacaranda mimosifolia D.Don, Justicia secunda Vahl., Piper pulchrum C.DC, P. paniculata L. and Spilanthes americana Hieron were evaluated against five bacteria (Staphylococcus aureus, Streptococcus ? hemolític, Bacillus cereus, Pseudomonas aeruginosa, and Escherichia coli), and one yeast (Candida albicans). These plants are used in Colombian folk medicine to treat infections of microbial origin. Methods Plants were collected by farmers and traditional healers. The ethanol, hexane and water extracts were obtained by standard methods. The antimicrobial activity was found by using a modified agar well diffusion method. All microorganisms were obtained from the American Type Culture Collection (ATCC). MIC was determined in the plant extracts that showed some efficacy against the tested microorganisms. Gentamycin sulfate (1.0 ?g/ml), clindamycin (0.3 ?g/ml) and nystatin (1.0 ?g/ml) were used as positive controls. Results The water extracts of Bidens pilosa L., Jacaranda mimosifolia D.Don, and Piper pulchrum C.DC showed a higher activity against Bacillus cereus and Escherichia coli than gentamycin sulfate. Similarly, the ethanol extracts of all species were active against Staphylococcus aureus except for Justicia secunda. Furthermore, Bixa orellana L, Justicia secunda Vahl. and Piper pulchrum C.DC presented the lowest MICs against Escherichia coli (0.8, 0.6 and 0.6 ?g/ml, respectively) compared to gentamycin sulfate (0.9 8g/ml). Likewise, Justicia secunda and Piper pulchrum C.DC showed an analogous MIC against Candida albicans (0.5 and 0.6 ?g/ml, respectively) compared to nystatin (0.6 ?g/ml). Bixa orellana L, exhibited a better MIC against Bacillus cereus (0.2 ?g/ml) than gentamycin sulfate (0.5 ?g/ml). Conclusion This in vitro study corroborated the antimicrobial activity of the selected plants used in folkloric medicine. All these plants were effective against three or more of the pathogenic microorganisms. However, they were ineffective against Streptococcus ? hemolytic and Pseudomonas aeruginosa. Their medicinal use in infections associated with these two species is not recommended. This study also showed that Bixa orellana L, Justicia secunda Vahl. and Piper pulchrum C.DC could be potential sources of new antimicrobial agents. PMID:16483385

Rojas, Jhon J; Ochoa, Veronica J; Ocampo, Saul A; Muńoz, John F

2006-01-01

224

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

E-print Network

Review Elicitors and priming agents initiate plant defense responses Paul W. Pare´ 1, *, Mohamed A: chemical elicitors, plant defense responses, plant volatile emissions, priming agents, volicitin Abstract to be a robust elicitor model for studying herbivore-induced plant defense responses. Here we review the role

Paré, Paul W.

225

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

226

In vitro activities of streptomycin and 11 oral antimicrobial agents against clinical isolates of Klebsiella rhinoscleromatis.  

PubMed Central

We tested in vitro the activities of streptomycin and tetracycline--antibiotics that have long been used to treat rhinoscleroma--as well as several newer oral agents by using 23 isolates of the causative organism Klebsiella rhinoscleromatis. All isolates were inhibited by clinically achievable concentrations of trimethoprim-sulfamethoxazole, amoxicillin-clavulanate, chloramphenicol, ciprofloxacin, cephalexin, cefuroxime, and cefpodoxime. PMID:1416867

Perkins, B A; Hamill, R J; Musher, D M; O'Hara, C

1992-01-01

227

Development of flexible antimicrobial films using essential oils as active agents.  

PubMed

The antimicrobial activity in the vapor-phase of laboratory-made flexible films of polypropylene (PP) and polyethylene/ethylene vinyl alcohol copolymer (PE/EVOH) incorporating essential oil of cinnamon ( Cinnamomum zeylanicum), oregano ( Origanum vulgare), clove ( Syzygium aromaticum), or cinnamon fortified with cinnamaldehyde was evaluated against a wide range of microorganisms: the Gram-negative bacteria Escherichia coli, Yersinia enterocolitica, Pseudomonas aeruginosa, and Salmonella choleraesuis; the Gram-positive bacteria Listeria monocytogenes, Staphylococcus aureus, Bacillus cereus, and Enterococcus faecalis; the molds Penicillium islandicum, Penicillium roqueforti, Penicillium nalgiovense, Eurotium repens, and A spergillus flavus and the yeasts Candida albicans, Debaryomyces hansenii, and Zigosaccharomyces rouxii. Films with a nominal concentration of 4% (w/w) of fortified cinnamon or oregano essential oil completely inhibited the growth of the fungi; higher concentrations were required to inhibit the Gram-positive bacteria (8 and 10%, respectively), and higher concentrations still were necessary to inhibit the Gram-negative bacteria. PP films were more effective than PE/EVOH films. The atmospheres generated by the antimicrobial films inside Petri dishes were quantitatively analyzed using headspace-single drop microextraction (HS-SDME) in combination with gas chromatography-mass spectrometry (GC-MS). The analyses showed that the oregano-fortified PP films released higher levels of carvacrol and thymol, and the cinnamon-fortified PP films released higher levels of cinnamaldehyde, during the first 3-6 h of incubation, than the corresponding PE/EVOH films. Shelf-life tests were also performed, demonstrating that the antifungal activities of the films persisted for more than two months after their manufacture. In addition, migration tests (overall and specific) were performed, using both aqueous and fatty simulants, to ensure that the films meet EU regulations regarding food contact materials. Following contact with the tested films, the substances that had migrated into the aqueous simulants were recovered by direct immersion-single drop extraction (DI-SDME) and then analyzed by GC-MS. The fatty stimulant (isooctane) was directly injected into the chromatographic system. PMID:17880148

López, P; Sánchez, C; Batlle, R; Nerín, C

2007-10-17

228

Antimicrobial Stewardship Programs  

PubMed Central

The development of antimicrobial agents represents one of the most significant achievements in medicine during the past century. However, the emergence of antimicrobial resistance combined with the downturn in the development of new antimicrobial agents in the pharmaceutical industry poses unanticipated challenges in the effective management of infection. The issue of how we can most effectively utilize these invaluable resources, antimicrobials, in the face of infections that are ever more difficult to treat arises. This issue serves as the fundamental basis for the concept of antimicrobial stewardship, the topic of this minireview. PMID:23926165

Leuthner, Kimberly D.

2013-01-01

229

Anticancer and Antimicrobial Activities of Some Antioxidant-Rich Cameroonian Medicinal Plants  

PubMed Central

Traditional remedies have a long-standing history in Cameroon and continue to provide useful and applicable tools for treating ailments. Here, the anticancer, antimicrobial and antioxidant activities of ten antioxidant-rich Cameroonian medicinal plants and of some of their isolated compounds are evaluated.The plant extracts were prepared by maceration in organic solvents. Fractionation of plant extract was performed by column chromatography and the structures of isolated compounds (emodin, 3-geranyloxyemodin, 2-geranylemodin) were confirmed spectroscopically. The antioxidant activity (AOA) was determined using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) bleaching method, the trolox equivalent antioxidant capacity (TEAC), and the hemoglobin ascorbate peroxidase activity inhibition (HAPX) assays. The anticancer activity was evaluated against A431 squamous epidermal carcinoma, WM35 melanoma, A2780 ovary carcinoma and cisplatin-resistant A2780cis cells, using a direct colorimetric assay. The total phenolic content in the extracts was determined spectrophotometrically by the Folin–Ciocalteu method. Rumex abyssinicus showed the best AOA among the three assays employed. The AOA of emodin was significantly higher than that of 3-geranyloxyemodin and 2-geranylemodin for both TEAC and HAPX methods. The lowest IC50 values (i.e., highest cytotoxicity) were found for the extracts of Vismia laurentii, Psorospermum febrifugum, Pentadesma butyracea and Ficus asperifolia. The Ficus asperifolia and Psorospermum febrifugum extracts are selective against A2780cis ovary cells, a cell line which is resistant to the standard anticancer drug cisplatin. Emodin is more toxic compared to the whole extract, 3-geranyloxyemodin and 2-geranylemodin. Its selectivity against the platinum-resistant A2780cis cell line is highest. All of the extracts display antimicrobial activity, in some cases comparable to that of gentamycin. PMID:23409075

Tamokou, Jean de Dieu; Chouna, Jean Rodolphe; Fischer-Fodor, Eva; Chereches, Gabriela; Barbos, Otilia; Damian, Grigore; Benedec, Daniela; Duma, Mihaela; Efouet, Alango Pepin Nkeng; Wabo, Hippolyte Kamdem; Kuiate, Jules Roger; Mot, Augustin; Silaghi-Dumitrescu, Radu

2013-01-01

230

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

231

Genetic diversity of Oenoccoccus oeni isolated from wines treated with phenolic extracts as antimicrobial agents.  

PubMed

Molecular techniques have been applied to study the evolution of wine-associated lactic acid bacteria from red wines produced in the absence and presence of antimicrobial phenolic extracts, eucalyptus leaves and almond skins, and to genetically characterize representative Oenococcus oeni strains. Monitoring microbial populations by PCR-DGGE targeting the rpoB gene revealed that O. oeni was, as expected, the species responsible for malolactic fermentation (MLF). Representative strains from both extract-treated and not-treated wines were isolated and all were identified as O. oeni species, by 16S rRNA sequencing. Typing of isolated O. oeni strains based on the mutation of the rpoB gene suggested a more favorable adaptation of L strains (n = 63) than H strains (n = 3) to MLF. Moreover, PFGE analysis of the isolated O. oeni strains revealed 27 different genetic profiles, which indicates a rich biodiversity of indigenous O. oeni species in the winery. Finally, a higher number of genetic markers were shown in the genome of strains from control wines than strains from wines elaborated with phenolic extracts. These results provide a basis for further investigation of the molecular and evolutionary mechanisms leading to the prevalence of O. oeni in wines treated with polyphenols as inhibitor compounds. PMID:24010607

García-Ruiz, Almudena; Tabasco, Raquel; Requena, Teresa; Claisse, Olivier; Lonvaud-Funel, Aline; Bartolomé, Begońa; Moreno-Arribas, M Victoria

2013-12-01

232

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

233

Cationic methacrylate polymers as topical antimicrobial agents against Staphylococcus aureus nasal colonization.  

PubMed

The in vitro and in vivo antimicrobial activity of primary ammonium ethyl methacrylate homopolymers (AEMPs) was investigated. AEMPs with different degrees of polymerization (DP = 7.7-12) were prepared by reversible addition-fragmentation chain-transfer (RAFT) polymerization. The AEMPs showed higher inhibitory effects against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), than Gram-negative bacteria. The AEMPs also showed potent anti-S. aureus activity in the presence of fetal bovine serum, whereas the activity of the antibiotic mupirocin was reduced under the same conditions. The AEMPs showed very little or no hemolytic activity. The cytotoxicity of AEMPs against mammalian cells HEp-2 and COS-7 was concentration-dependent, and the cell viability significantly decreased at higher polymer concentrations. The AEMPs significantly reduced the number of viable S. aureus cells in the nasal environment of cotton rats when compared to that of the control. This study demonstrates that AEMPs have potential for use in treating topical S. aureus infections. PMID:25010735

Thoma, Laura M; Boles, Blaise R; Kuroda, Kenichi

2014-08-11

234

Comparative evaluation of the E test, agar dilution, and broth microdilution for testing susceptibilities of Helicobacter pylori strains to 20 antimicrobial agents.  

PubMed Central

The Epsilometer test (E test; AB Biodisk, Solna, Sweden), a new quantitative technique for the determination of antimicrobial susceptibility, was compared to reference methods (agar dilution and broth microdilution) for the antimicrobial susceptibility testing of Helicobacter pylori. Seventy-one H. pylori strains isolated from patients with duodenal ulcers were tested against 20 antimicrobial agents. The E test and the agar dilution method were carried out on Mueller-Hinton agar; the broth microdilution method was performed with Mueller-Hinton broth. The E-test results showed excellent correlation with the agar dilution results, with 91.3 and 98.8% agreement within 1 and 2 log2 dilution steps, respectively, in a total of 1,350 tests. The correlation between the E-test results and the broth microdilution results was slightly higher, with 91.6 and 99.1% agreement within 1 and 2 log2 dilution steps, respectively, in a total of 1,317 tests. There were six major errors and two very major errors by the metronidazole E test compared to the results obtained by reference methods. Excellent agreement between E-test, agar dilution, and broth microdilution results was found for resistance to erythromycin (8%), clarithromycin (6%), and tetracycline (6%). Our results confirm that the E test is comparable to standardized methods for susceptibility testing. Therefore, the E test is a reliable and alternative method for testing H. pylori susceptibility to a wide range of antimicrobial agents in clinical practice. PMID:9196205

Piccolomini, R; Di Bonaventura, G; Catamo, G; Carbone, F; Neri, M

1997-01-01

235

Antimicrobial activity of {gamma}-thionin-like soybean SE60 in E. coli and tobacco plants  

SciTech Connect

The SE60, a low molecular weight, sulfur-rich protein in soybean, is known to be homologous to wheat {gamma}-purothionin. To elucidate the functional role of SE60, we expressed SE60 cDNA in Escherichia coli and in tobacco plants. A single protein band was detected by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) after anti-FLAG affinity purification of the protein from transformed E. coli. While the control E. coli cells harboring pFLAG-1 showed standard growth with Isopropyl {beta}-D-1-thiogalactopyranoside (IPTG) induction, E. coli cells expressing the SE60 fusion protein did not grow at all, suggesting that SE60 has toxic effects on E. coli growth. Genomic integration and the expression of transgene in the transgenic tobacco plants were confirmed by Southern and Northern blot analysis, respectively. The transgenic plants demonstrated enhanced resistance against the pathogen Pseudomonas syringae. Taken together, these results strongly suggest that SE60 has antimicrobial activity and play a role in the defense mechanism in soybean plants.

Choi, Yeonhee [School of Biological Sciences, Seoul National University, Seoul 151-747 (Korea, Republic of)], E-mail: yhc@snu.ac.kr; Choi, Yang Do [Department of Agricultural Biotechnology and Center for Agricultural Biomaterials, Seoul National University, Seoul 151-921 (Korea, Republic of); Lee, Jong Seob [School of Biological Sciences, Seoul National University, Seoul 151-747 (Korea, Republic of)], E-mail: jongslee@plaza.snu.ac.kr

2008-10-17

236

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?, Dejan S; Savikin, Katarina P; Stevi?, Tatjana R; Bigovi?, Dubravka J

2014-08-01

237

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

238

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

239

Antimicrobial activity of olive solutions from stored Alpeorujo against plant pathogenic microorganisms.  

PubMed

The aim of this work was to assess the in vitro antimicrobial effects that wastewaters from alpeorujo oil extraction have against phytopathogenic bacteria and fungi. Alpeorujo was stored for 6 months and then processed to extract its oil, pomace, and a new liquid waste (OWSA), which was characterized by its content in phenolic compounds. OWSA at 20% decreased bu >4 log the population of Erwinia spp., Pseudomonas spp., and Clavibacter spp. viable cells in test tubes, whereas OWSA at 50% in agar medium was necessary to inhibit mycelial growth of most fungi. It was found that the bactericidal effect was due to the joint action of low molecular mass phenolic compounds, although neither hydroxytyrosol, its glucosides, hydroxytyrosol glycol, nor a glutaraldehyde-like compound individually explained this bioactivity. Hence, OWSA constitutes a promising natural solution to fight plant phytopathogenic bacteria and fungi. PMID:21630653

Medina, Eduardo; Romero, Concepcion; de Los Santos, Berta; de Castro, Antonio; Garcia, Aranzazu; Romero, Fernando; Brenes, Manuel

2011-07-13

240

General Principles of Antimicrobial Therapy  

PubMed Central

Antimicrobial agents are some of the most widely, and often injudiciously, used therapeutic drugs worldwide. Important considerations when prescribing antimicrobial therapy include obtaining an accurate diagnosis of infection; understanding the difference between empiric and definitive therapy; identifying opportunities to switch to narrow-spectrum, cost-effective oral agents for the shortest duration necessary; understanding drug characteristics that are peculiar to antimicrobial agents (such as pharmacodynamics and efficacy at the site of infection); accounting for host characteristics that influence antimicrobial activity; and in turn, recognizing the adverse effects of antimicrobial agents on the host. It is also important to understand the importance of antimicrobial stewardship, to know when to consult infectious disease specialists for guidance, and to be able to identify situations when antimicrobial therapy is not needed. By following these general principles, all practicing physicians should be able to use antimicrobial agents in a responsible manner that benefits both the individual patient and the community. PMID:21282489

Leekha, Surbhi; Terrell, Christine L.; Edson, Randall S.

2011-01-01

241

ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, Mar. 2002, p. 875878 Vol. 46, No. 3 0066-4804/02/$04.00 0 DOI: 10.1128/AAC.46.3.875878.2002  

E-print Network

ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, Mar. 2002, p. 875­878 Vol. 46, No. 3 0066-4804/02/$04.00 0 antibiotics against gram-negative bacteria (5). Although not completely unveiled, the mechanism of action

Pompeu Fabra, Universitat

242

The antimicrobial activity of a dentin conditioner combined with antibacterial agents.  

PubMed

Dental hand instruments are not efficient in removing all infected dentin when performing carious removal for minimal intervention techniques. The use of an antibacterial dentin conditioner may therefore be useful when restoring cavities that have residual carious dentin. Antibacterial agents--chlorhexidine hydrochloride, cetylpyridinium chloride, cetrimide, benzaIkonium chloride and sodium hypochlorite, were added either to a dentin conditioner used for glass ionomer cements or distilled water at 1% concentration. Dentin conditioning solutions at pH 2.5, 4.9 and 7.7 were also prepared, along with 1% aqueous thymol. Using an agar diffusion test, 25 microl aliquots were examined for their inhibitory effects on three cariogenic bacteria. After 24 hours, an agar pellet was extracted adjacent to the agar well and placed on a second inoculated agar plate to observe sustained inhibitory effects, after which this procedure was repeated one more time. Antibacterial dentin conditioners showed significant inhibitory effect compared to the control over the three test periods (p<0.016). The combination of dentin conditioners with antibacterial agents significantly reduced the inhibitory effect compared to the antibacterial aqueous solutions (p<0.016). One-percent aqueous thymol showed no inhibitory effect against the test bacteria. The cetrimide-dentin conditioner showed the greatest inhibitory effect against all three test bacteria over the three experimental periods (p<0.016). The inhibitory effect of antibacterial agents was significantly reduced when combined with a dentin conditioner. Only the cetrimide-dentin conditioner combination produced significant inhibitory effects against all three test organisms. PMID:15765961

Botelho, Michael G

2005-01-01

243

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

244

The Longus Type IV Pilus of Enterotoxigenic Escherichia coli (ETEC) Mediates Bacterial Self-aggregation and Protection from Antimicrobial Agents  

PubMed Central

Enterotoxigenic Escherichia coli (ETEC) strains are leading causes of childhood diarrhea in developing countries. ETEC pili and non-pili adherence factors designated colonization surface antigens (CSA) are believed to be important in the pathogenesis of diarrhea. Longus, a type IV pilus identified as the CSA21, is expressed in up to one-third of ETEC strains, and share similarities to the toxin-coregulated pilus of Vibrio cholerae, and the bundle-forming pilus of enteropathogenic E. coli. To identify longus phenotype and possible function, a site-directed mutation of the lngA major subunit gene in the E9034A wild type ETEC strain was constructed. Lack of longus expression from the lngA mutant was demonstrated by immunoblot analysis and electron microscopy using specific anti-LngA antibody. Formation of self-aggregates by ETEC was shown to be dependent on longus expression as the lngA mutant or wild type grown under poor longus-expression conditions was unable to express this phenotype. Longus-expressing ETEC were also associated with improved survival when exposed to antibacterial factors including lysozyme and antibiotics. This suggests that longus-mediated bacterial self-aggregates protect bacteria against antimicrobial environmental agents and may promote gut colonization. PMID:20227481

Clavijo, Andrea P.; Bai, Jing; Gomez-Duarte, Oscar G.

2010-01-01

245

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

246

Comparison of sensititre dried microtitration trays with a standard agar method for determination of minimum inhibitory concentrations of antimicrobial agents.  

PubMed Central

A total of 222 clinical isolates were used to test the accuracy of Sensititre dried microtitration trays for determining minimum inhibitory concentrations (MICs) of antimicrobial agents. In comparison with an agar dilution technique, 89.5% of all the pairs of results were within one doubling dilution. The 2,420 pairs of MIC results with finite values gave a corresponding figure of 86.8%. Exclusion of sulfisoxazole results, which demonstrated a significant interlaboratory variation in accuracy, raised this value to 89.1%. Very good differentiation of beta-lactamase-producing strains of Staphylococcus aureus (24 of 24 giving an MIC greater than or equal to 0.25 micrograms/ml) and Haemophilus influenzae (3 of 3 giving an MIC greater than or equal to 32 micrograms/ml) was obtained with the Sensititre system. This method also clearly distinguished erythromycin-resistant S. aureus strains (7 of 7 giving an MIC greater than 32 micrograms/ml) from the susceptible strains (26 of 28 giving an MIC less than or equal to 0.5 microgram/ml plus 1 strain at 1.0 microgram/ml and 1 at 2.0 micrograms/ml). Sensititre offers an accurate and convenient method of determining MICs comparable to those obtained with the agar dilution procedure, with the advantage of an extended shelf life when stored at room temperature. PMID:6972192

Reeves, D S; Holt, A; Bywater, M J; Wise, R; Logan, M N; Andrews, J M; Broughall, J M

1980-01-01

247

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

248

Antimicrobial agents in the management of urinary tract infection: an experimental evaluation.  

PubMed

Persistent and recurrent infections of the urinary tract are a formidable clinical problem, but several recently developed antibiotics have properties that suggest an increased ability to eradicate such infections. Three of the new-generation antibiotics were compared with established agents by using animal models of urinary tract infection. Of the antibiotics tested, gentamicin and ceftriaxone alone were capable of eradicating infection from acute and chronically infected kidney tissue. Chronic lower urinary tract infection was best managed by using norfloxacin or ceftriaxone. Gentamicin, aztreonam, cotrimoxazole and ampicillin were much less effective. In subacute pyelonephritis, gentamicin, aztreonam, norfloxacin and ceftriaxone successfully eliminated microorganisms from most of the infected kidneys, whereas ampicillin and cotrimoxazole had little effect on bacterial numbers. The data have provided an experimental basis for the selection of antibiotics in the management of persistent urinary tract infection. PMID:2681480

Lecamwasam, J P; Miller, T E

1989-11-01

249

Impact of Feed Supplementation with Antimicrobial Agents on Growth Performance of Broiler Chickens, Clostridium perfringens and Enterococcus Counts, and Antibiotic Resistance Phenotypes and Distribution of Antimicrobial Resistance Determinants in Escherichia coli Isolates?  

PubMed Central

The effects of feed supplementation with the approved antimicrobial agents bambermycin, penicillin, salinomycin, and bacitracin or a combination of salinomycin plus bacitracin were evaluated for the incidence and distribution of antibiotic resistance in 197 commensal Escherichia coli isolates from broiler chickens over 35 days. All isolates showed some degree of multiple antibiotic resistance. Resistance to tetracycline (68.5%), amoxicillin (61.4%), ceftiofur (51.3%), spectinomycin (47.2%), and sulfonamides (42%) was most frequent. The levels of resistance to streptomycin, chloramphenicol, and gentamicin were 33.5, 35.5, and 25.3%, respectively. The overall resistance levels decreased from day 7 to day 35 (P < 0.001). Comparing treatments, the levels of resistance to ceftiofur, spectinomycin, and gentamicin (except for resistance to bacitracin treatment) were significantly higher in isolates from chickens receiving feed supplemented with salinomycin than from the other feeds (P < 0.001). Using a DNA microarray analysis capable of detecting commonly found antimicrobial resistance genes, we characterized 104 tetracycline-resistant E. coli isolates from 7- to 28-day-old chickens fed different growth promoters. Results showed a decrease in the incidence of isolates harboring tet(B), blaTEM, sulI, and aadA and class 1 integron from days 7 to 35 (P < 0.01). Of the 84 tetracycline-ceftiofur-resistant E. coli isolates, 76 (90.5%) were positive for blaCMY-2. The proportions of isolates positive for sulI, aadA, and integron class 1 were significantly higher in salinomycin-treated chickens than in the control or other treatment groups (P < 0.05). These data demonstrate that multiantibiotic-resistant E. coli isolates can be found in broiler chickens regardless of the antimicrobial growth promoters used. However, the phenotype and the distribution of resistance determinants in E. coli can be modulated by feed supplementation with some of the antimicrobial agents used in broiler chicken production. PMID:17827305

Diarra, Moussa S.; Silversides, Fred G.; Diarrassouba, Fatoumata; Pritchard, Jane; Masson, Luke; Brousseau, Roland; Bonnet, Claudie; Delaquis, Pascal; Bach, Susan; Skura, Brent J.; Topp, Edward

2007-01-01

250

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

251

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

252

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

253

Correlation between in vitro and in vivo activity of antimicrobial agents against gram-negative bacilli in a murine infection model.  

PubMed Central

We studied the relationship between in vitro susceptibility tests (MICs, MBCs) and in vivo activity of tobramycin, pefloxacin, ceftazidime, and imipenem against 15 gram-negative bacilli from five different species in a murine thigh infection model. Complete dose-response curves were determined for each antimicrobial agent against each strain, and three parameters of in vivo activity were defined: maximal attainable antimicrobial effect (i.e., reduction in log10 CFU per thigh compared with untreated controls) at 24 h (Emax), total dose required to reach 50% of maximal effect (P50), and total dose required to achieve a bacteriostatic effect (static dose). Pefloxacin demonstrated the greatest Emax (P less than 0.05). Tobramycin was the most potent antimicrobial agent, as indicated by its having the lowest static dose/MIC ratio (P less than 0.002). Log10 P50s and static doses correlated significantly with log10 MICs or MBCs for the 15 strains of each antibiotic (P less than 0.01) except imipenem (P greater than 0.50). The greater potency of imipenem against the three Pseudomonas aeruginosa strains than against strains of the family Enterobacteriaceae (P less than 0.01) explained this lack of correlation. A longer duration of postantibiotic effect for imipenem against P. aeruginosa (P = 0.02) contributed to its increased potency against these strains. We conclude that in vitro susceptibility tests correlated well with in vivo activity in this animal model and that variations in potency among the four antimicrobial agents could be explained by differences in pharmacokinetics or pharmacodynamic activity. PMID:1929302

Fantin, B; Leggett, J; Ebert, S; Craig, W A

1991-01-01

254

Search for antibacterial and antifungal agents from selected Indian medicinal plants  

Microsoft Academic Search

A series of 61 Indian medicinal plants belonging to 33 different families used in various infectious disorders, were screened for their antimicrobial properties. Screening was carried out at 1000 and 500?g\\/ml concentrations by agar dilution method against Bacillus cereus var mycoides, Bacillus pumilus, Bacillus subtilis, Bordetella bronchiseptica, Micrococcus luteus, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Streptococcus

V. Prashanth Kumar; Neelam S. Chauhan; Harish Padh; M. Rajani

2006-01-01

255

The fatty acid synthase inhibitor triclosan: repurposing an anti-microbial agent for targeting prostate cancer.  

PubMed

Inhibition of FASN has emerged as a promising therapeutic target in cancer, and numerous inhibitors have been investigated. However, severe pharmacological limitations have challenged their clinical testing. The synthetic FASN inhibitor triclosan, which was initially developed as a topical antibacterial agent, is merely affected by these pharmacological limitations. Yet, little is known about its mechanism in inhibiting the growth of cancer cells. Here we compared the cellular and molecular effects of triclosan in a panel of eight malignant and non-malignant prostate cell lines to the well-known FASN inhibitors C75 and orlistat, which target different partial catalytic activities of FASN. Triclosan displayed a superior cytotoxic profile with a several-fold lower IC50 than C75 or orlistat. Structure-function analysis revealed that alcohol functionality of the parent phenol is critical for inhibitory action. Rescue experiments confirmed that end product starvation was a major cause of cytotoxicity. Importantly, triclosan, C75 and orlistat induced distinct changes to morphology, cell cycle, lipid content and the expression of key enzymes of lipid metabolism, demonstrating that inhibition of different partial catalytic activities of FASN activates different metabolic pathways. These finding combined with its well-documented pharmacological safety profile make triclosan a promising drug candidate for the treatment of prostate cancer. PMID:25313139

Sadowski, Martin C; Pouwer, Rebecca H; Gunter, Jennifer H; Lubik, Amy A; Quinn, Ronald J; Nelson, Colleen C

2014-10-15

256

Synthesis of potent inhibitors of ?-ketoacyl-acyl carrier protein synthase III as potential antimicrobial agents.  

PubMed

Mycobacterium tuberculosis FabH, an essential enzyme in the mycolic acid biosynthetic pathway, is an attractive target for novel anti-tubercolosis agents. Structure-based design and synthesis of 1-(4-carboxybutyl)-4-(4-(substituted benzyloxy)phenyl)-1H-pyrrole-2-carboxylic acid derivatives 7a-h, a subset of eight potential FabH inhibitors, is described in this paper. The Vilsmeier-Haack reaction was employed as a key step. The structures of all the newly synthesized compounds were identified by IR, ąH-NMR, ąłC-NMR, ESI-MS and HRMS. The alamarBlue™ microassay was employed to evaluate the compounds 7a-h against Mycobacterium tuberculosis H??Rv. The results demonstrate that the compound 7d possesses good in vitro antimycobacterial activity against Mycobacterium tuberculosis H??Rv (Minimum Inhibitory Concentration value [MIC], 12.5 µg/mL).These compounds may prove useful in the discovery and development of new anti-tuberculosis drugs. PMID:22534662

Liu, Yan; Zhong, Wu; Li, Rui-Juan; Li, Song

2012-01-01

257

Antimicrobial Agents Produced by Marine Aspergillus terreus var. africanus Against Some Virulent Fish Pathogens.  

PubMed

Screening of fungal isolates collected from different locations of Alexandria coast, Egypt, was carried out to obtain new biologically active metabolites against some virulent fish pathogens (Edwardsiella tarda, Aeromonas hydrophila, Vibrio ordalli and Vibrio angularuim). Among 26 fungal isolates, Aspergillus terreus var. africanus was identified as the most potent isolate. Production of the bioactive material was optimized using response surface methodology including fermentation media, incubation period, temperature, pH, and thermo-stability. Spectral properties of the gas chromatography/mass spectrum of the ethyl acetate crude extract were determined. Partially purified components of the crude extract were chromatographically separated and bioassayed. Out of ten separated compounds, five were with considerable antibacterial agent. The bio-toxicity of crude showed a slight toxicity against the brine shrimp Artemia salina (LC50 = 1,500 ?g/l). Antibacterial activity of the crude was compared with some known standard antibiotics and found to be superior over many where its MIC against some pathogen reached 1 ?g/ml. PMID:23997326

Barakat, Khouloud M; Gohar, Yousry M

2012-09-01

258

Antimicrobial Activity of Isothiocyanates from Cruciferous Plants against Methicillin-Resistant Staphylococcus aureus (MRSA).  

PubMed

Purified isothiocyanates from cruciferous plants (Brassicacea, Syn. Cruciferae) plants were evaluated against 15 isolates of methicillin-resistant S. aureus isolated from diabetic foot-ulcer patients aiming the study of the potential usage of allyl-isothiocyanate, benzyl-isothiocyanate and 2-phenylethyl-isothiocyanate against this important bacteria. Disc diffusion and minimum inhibitory concentration methods were used to access the antimicrobial activity. The index (Ia) and rate (Ra) of the antibacterial activity for each compound were calculated. The results showed a highly dose-dependent compound and chemical structure antibacterial effectiveness. The results showed a strong relation between the chemical structure of isothiocyanates and its antibacterial effectiveness. The benzyl-isothiocyanate was the most effective with a minimum inhibitory concentration varying between 2.9 and 110 µg·mL-1 with an antibacterial activity rate up to 87%. Moreover, their antibacterial activity was mainly bactericidal. This study provides scientific evidence that isothiocyanates have an interesting biological value and must be considered as an important tool to be used against MRSA. PMID:25353177

Dias, Carla; Aires, Alfredo; Saavedra, Maria José

2014-01-01

259

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

260

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

261

Efficacy of plant-derived antimicrobials as antimicrobial wash treatments for reducing enterohemorrhagic Escherichia coli O157:H7 on apples.  

PubMed

This study investigated the efficacy of 3 GRAS-status, plant-derived antimicrobials (PDAs), trans-cinnamaldehyde (TC), carvacrol (CR), and ?-resorcylic acid (BR) applied as an antimicrobial wash for killing Escherichia coli O157:H7 on apples. "Red delicious" apples inoculated with a 5 strain mixture of E. coli O157:H7 were subjected to washing in sterile deionized water containing 0% PDA (control), 0.15% TC, 0.35% TC, 0.15% CR, 0.30% CR, 0.5% BR, or 1% BR for 1, 3, and 5 min at 23 °C in the presence and absence of 1% soil, and surviving pathogen populations on apples were enumerated at each specified time. All PDAs were more effective in reducing E. coli O157:H7 compared to the water wash treatment (P < 0.05) and reduced the pathogen by 4- to 5-log CFU/apple in 5 min. Chlorine (1%) was the most effective treatment reducing the pathogen on apples to undetectable levels in 1 min (P < 0.05). Moreover, the antimicrobial effect of CR and BR was not affected by the presence of soil, whereas the efficacy of TC and BR was decreased in the presence of soil. Further, no bacteria were detected in the wash solution containing CR and BR; however, E. coli O157:H7 was recovered in the control wash water and treatment solutions containing TC and chlorine, in the presence of 1% soil (P < 0.05). Results suggest that the aforementioned PDAs, especially CR and BR could be used effectively to kill E. coli O157:H7 on apples when used as a wash treatment. Studies on the sensory and quality characteristics of apples treated with PDAs are needed before recommending their usage. PMID:24024692

Baskaran, Sangeetha Ananda; Upadhyay, Abhinav; Kollanoor-Johny, Anup; Upadhyaya, Indu; Mooyottu, Shankumar; Roshni Amalaradjou, Mary Anne; Schreiber, David; Venkitanarayanan, Kumar

2013-09-01

262

Antimicrobial activity, toxicity and the isolation of a bioactive compound from plants used to treat sexually transmitted diseases.  

PubMed

Extracts of six ethnobotanically selected medicinal plants (Anredera cordifolia, Elaeodendron transvaalense, Elephantorrhiza burkei, Senna petersiana, Terminalia sericea and Rauvolfia caffra) used traditionally to treat sexually transmitted diseases (STD's) were investigated for antibacterial activity using the agar dilution method. Of the six collected, Terminalia sericea, Senna petersiana and Anredera cordifolia were also investigated for cytotoxicity. The phytochemical studies on Senna petersiana resulted in the isolation of luteolin, which also showed antimicrobial activity. Only the Senna petersiana extract and luteolin isolated from it were tested for antiviral activity and showed some activity at the highest non-toxic concentration of 24 and 500 microg/ml, respectively. The results of the antimicrobial screening support the ethnomedicinal uses of these plants to some extent. PMID:15619572

Tshikalange, T E; Meyer, J J M; Hussein, A A

2005-01-15

263

Phenolic characterization and antimicrobial activity of folk medicinal plant extracts for their applications in olive production.  

PubMed

Phytophthora spp is important in plant pathology due to the importance of the diseases it causes. In olive trees, severe damages are caused by the disease known as "dry branch" occasioned by Phytophthora nicotianae, P. citrophthora and P. palmivora. Much effort has been made to find efficient methods of control, with a low negative impact on environment. In this regard, treatment with plant extracts is a valid strategy. The aims of the present study are (i) to determine the polyphenol composition of extracts of Thymus vulgaris, Origanum vulgare, Matricaria recutita, and Larrea divaricata by CZE, (ii) correlate the analytical composition of these extracts with the inhibition on the mycelial growth, and (iii) determine the individual antimicrobial activity of the most active ingredients. A simple methodology was developed for the determination of catechin, naringenin, cinnamic acid, syringic acid, chlorogenic acid, apigenin, vanillic acid, luteolin, quercetin, and caffeic acid in plant extracts by CZE. The extraction of phenolic compounds in extract was performed by a miniaturized solid phase extraction using a home-made minicolumn packed with suitable filtering material (C18 , 50 mg). The optimized analyses conditions were: 30 mM boric acid buffer, pH 9.50; capillary, 57 cm full length, 50 cm effective length, 75 ?m id, hydrodynamic injection 30 mbar, 2 s; 25 kV; 25°C, detection by UV absorbance at 290 nm. Sample results suggest that phenolic composition seems to have a great influence on inhibition of pathogens. The highest inhibitions of mycelial growth were observed for cinnamic acid and naringenin. PMID:24668423

Boiteux, Joana; Soto Vargas, Carolina; Pizzuolo, Pablo; Lucero, Gabriela; Silva, María Fernanda

2014-06-01

264

Antimicrobial activity of diterpenoids from hairy roots of Salvia sclarea L.: Salvipisone as a potential anti-biofilm agent active against antibiotic resistant Staphylococci  

Microsoft Academic Search

The antimicrobial activities of crude dichloromethane fractions from acetone extracts of Agrobacterium rhizogenes transformed roots and roots of field-grown plants of Salvia sclarea as well as four pure abietane diterpenoids isolated from the hairy root cultures were determined. The growth of Gram-positive bacteria (Staphylococcus aureus, S. epidermidis, Enterococcus faecalis) but not Gram-negative ones (Escherichia coli, Pseudomonas aeruginosa) or pathogenic fungi

?. Ku?ma; M. Ró?alski; E. Walencka; B. Ró?alska; H. Wysoki?ska

2007-01-01

265

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

266

Determination of susceptibilities of 26 Leptospira sp. serovars to 24 antimicrobial agents by a broth microdilution technique.  

PubMed

The MICs of 24 antimicrobials for 26 Leptospira spp. serovars were determined using a broth microdilution technique. The MICs at which 90% of isolates tested were inhibited (MIC(90)s) of cefepime, imipenem-cilastatin, erythromycin, clarithromycin, and telithromycin were all /=3.13 microg/ml. Many antimicrobials have excellent in vitro activity against Leptospira. PMID:15388465

Murray, Clinton K; Hospenthal, Duane R

2004-10-01

267

Natural products as antibacterial agents  

Microsoft Academic Search

For thousands of years medicinal plants have played a significant role in the treatment of a wide range of medical conditions, including infectious diseases. Some naturally occurring chemical compounds serve as models for a large percentage clinically proven drugs, and many are now being re-assessed as antimicrobial agents. The primary reason for this renaissance is the fact that infectious disease

Gail B. Mahady; Yue Huang; Brian J. Doyle; Tracie Locklear

2008-01-01

268

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

269

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

270

Metabolization of the bacteriostatic agent triclosan in edible plants and its consequences for plant uptake assessment.  

PubMed

Persistent environmental contaminants may enter agricultural fields via the application of sewage sludge, by irrigation with treated municipal wastewater or by manuring. It has been shown that such contaminants can be incorporated into crop plants. The metabolism of the bacteriostatic agents triclocarban, triclosan, and its transformation product methyl triclosan was investigated after their uptake into carrot cell cultures. A fast metabolization of triclosan was observed and eight so far unknown phase II metabolites, conjugates with saccharides, disaccharides, malonic acid, and sulfate, were identified by liquid chromatography-mass spectrometry. Triclocarban and methyl triclosan lack a phenolic group and remained unaltered in the cell cultures. Phase I metabolization was not observed for any of the compounds. All eight triclosan conjugates identified in the cell cultures were also detected in extracts of intact carrot plants cultivated on triclosan contaminated soils. Their total amount in the plants was assessed to exceed the amount of the triclosan itself by a factor of 5. This study shows that a disregard of conjugates in studies on plant uptake of environmental contaminants may severely underestimates the extent of uptake into plants and, eventually, the potential human exposure to contaminants via food of plant origin. PMID:22989227

Macherius, André; Eggen, Trine; Lorenz, Wilhelm; Moeder, Monika; Ondruschka, Jelka; Reemtsma, Thorsten

2012-10-01

271

Transgenic Brassica juncea plants expressing MsrA1, a synthetic cationic antimicrobial peptide, exhibit resistance to fungal phytopathogens.  

PubMed

Cationic antimicrobial peptides (CAPs) have shown potential against broad spectrum of phytopathogens. Synthetic versions with desirable properties have been modeled on these natural peptides. MsrA1 is a synthetic chimera of cecropin A and melittin CAPs with antimicrobial properties. We generated transgenic Brassica juncea plants expressing the msrA1 gene aimed at conferring fungal resistance. Five independent transgenic lines were evaluated for resistance to Alternaria brassicae and Sclerotinia sclerotiorum, two of the most devastating pathogens of B. juncea crops. In vitro assays showed inhibition by MsrA1 of Alternaria hyphae growth by 44-62 %. As assessed by the number and size of lesions and time taken for complete leaf necrosis, the Alternaria infection was delayed and restricted in the transgenic plants with the protection varying from 69 to 85 % in different transgenic lines. In case of S. sclerotiorum infection, the lesions were more severe and spread profusely in untransformed control compared with transgenic plants. The sclerotia formed in the stem of untransformed control plants were significantly more in number and larger in size than those present in the transgenic plants where disease protection of 56-71.5 % was obtained. We discuss the potential of engineering broad spectrum biotic stress tolerance by transgenic expression of CAPs in crop plants. PMID:24452332

Rustagi, Anjana; Kumar, Deepak; Shekhar, Shashi; Yusuf, Mohd Aslam; Misra, Santosh; Sarin, Neera Bhalla

2014-06-01

272

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

273

Antimicrobial evaluation of some medicinal plants for their anti-enteric potential against multi-drug resistant Salmonella typhi.  

PubMed

Screening was done of some plants of importance in the Ayurvedic system of traditional medicine used in India to treat enteric diseases. Fifty four plant extracts (methanol and aqueous) were assayed for their activity against multi-drug resistant Salmonella typhi. Strong antibacterial activity was shown by the methanol extracts of Aegle marmelos, Salmalia malabarica, Punica granatum, Myristica fragrans, Holarrhena antidysenterica, Terminalia arjuna and Triphal (mixture of Emblica of fi cinalis, Terminalia chebula and Terminalia belerica). Moderate antimicrobial activity was shown by Picorhiza kurroa, Acacia catechu, Acacia nilotica, Cichorium intybus, Embelia ribes, Solanum nigrum, Carum copticum, Apium graveolens, Ocimum sanctum, Peucedanum graveolens and Butea monosperma. PMID:15476301

Rani, Phulan; Khullar, Neeraj

2004-08-01

274

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

275

C-PAmP: Large Scale Analysis and Database Construction Containing High Scoring Computationally Predicted Antimicrobial Peptides for All the Available Plant Species  

PubMed Central

Background Antimicrobial peptides are a promising alternative to conventional antibiotics. Plants are an important source of such peptides; their pharmacological properties are known since antiquity. Access to relevant information, however, is not straightforward, as there are practically no major repositories of experimentally validated and/or predicted plant antimicrobial peptides. PhytAMP is the only database dedicated to plant peptides with confirmed antimicrobial action, holding 273 entries. Data on such peptides can be otherwise retrieved from generic repositories. Description We present C-PAmP, a database of computationally predicted plant antimicrobial peptides. C-PAmP contains 15,174,905 peptides, 5–100 amino acids long, derived from 33,877 proteins of 2,112 plant species in UniProtKB/Swiss-Prot. Its web interface allows queries based on peptide/protein sequence, protein accession number and species. Users can view the corresponding predicted peptides along with their probability score, their classification according to the Collection of Anti-Microbial Peptides (CAMP), and their PhytAMP id where applicable. Moreover, users can visualise protein regions with a high concentration of predicted antimicrobial peptides. In order to identify potential antimicrobial peptides we used a classification algorithm, based on a modified version of the pseudo amino acid concept. The classifier tested all subsequences ranging from 5 to 100 amino acids of the plant proteins in UniProtKB/Swiss-Prot and stored those classified as antimicrobial with a high probability score (>90%). Its performance measures across a 10-fold cross-validation are more than satisfactory (accuracy: 0.91, sensitivity: 0.93, specificity: 0.90) and it succeeded in classifying 99.5% of the PhytAMP peptides correctly. Conclusions We have compiled a major repository of predicted plant antimicrobial peptides using a highly performing classification algorithm. Our repository is accessible from the web and supports multiple querying options to optimise data retrieval. We hope it will greatly benefit drug design research by significantly limiting the range of plant peptides to be experimentally tested for antimicrobial activity. PMID:24244550

Niarchou, Anastasia; Alexandridou, Anastasia; Athanasiadis, Emmanouil; Spyrou, George

2013-01-01

276

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

277

Longitudinal analysis of the association of human salivary antimicrobial agents with caries increment and cariogenic micro-organisms: a two-year cohort study.  

PubMed

Previous studies of the possible associations of salivary antimicrobial agents with dental caries have given controversial results, obviously mainly because almost all studies have been cross-sectional. Our aim was to find out, in a two-year longitudinal follow-up study, the associations among selected salivary non-immune and immune antimicrobial variables, cariogenic bacteria, and caries increment. The study population was comprised of 63 subjects, all of whom had their 13th birthday during the first study year. In addition to a comprehensive dental examination at baseline and after 2 yrs, paraffin-stimulated whole saliva samples were collected in a standardized way at six-month intervals. Saliva samples were analyzed for flow rate, buffer effect, lysozyme, lactoferrin, total peroxidase activity, hypothiocyanite, thiocyanate, agglutination rate, and total and specific anti-S. mutans IgA and IgG, as well as for numbers of total and mutans streptococci, lactobacilli, and total anaerobic bacteria. Cluster analysis and Spearman-Rank correlation coefficients were used to explore possible associations between and among the studied variables. During the two-year period, a statistically significant increase was observed in flow rate, thiocyanate, agglutination rate, anti-S. mutans IgA antibodies, lactobacilli, and total anaerobes, whereas lysozyme, lactoferrin, and total and anti-S. mutans IgG antibodies declined significantly. Based on various analyses, it can be concluded that, at baseline, total IgG and hypothiocyanite had an inverse relationship with subsequent two-year caries increment, anti-S. mutans IgG antibodies increased with caries development, and mutans streptococci and lactobacilli correlated positively with both baseline caries and caries increment. Total anaerobic microflora was consistently more abundant among caries-free individuals. In spite of the above associations, we conclude that none of the single antimicrobial agents as such has sufficiently strong power to have diagnostic significance in vivo with respect to future caries. PMID:9437402

Kirstilä, V; Häkkinen, P; Jentsch, H; Vilja, P; Tenovuo, J

1998-01-01

278

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

, broad-spectrum antimicrobial activity as potent as previously reported dodecameric peptoids to be integral to their activities. In recent years, development of linear antimicrobial peptides has shifted cationic peptides with antimicrobial activity. Peptoid synthesis enables facile incorporation

Barron, Annelise E.

279

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

280

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

281

Use of Genetically Engineered Phage To Deliver Antimicrobial Agents to Bacteria: an Alternative Therapy for Treatment of Bacterial Infections  

Microsoft Academic Search

The emergence and increasing prevalence of multidrug-resistant bacterial pathogens emphasizes the need for new and innovative antimicrobial strategies. Lytic phages, which kill their host following amplification and release of progeny phage into the environment, may offer an alternative strategy for combating bacterial infections. In this study, however, we describe the use of a nonlytic phage to specifically target and deliver

Caroline Westwater; Laura M. Kasman; David A. Schofield; Phillip A. Werner; Joseph W. Dolan; Michael G. Schmidt; James S. Norris

2003-01-01

282

Silver nanoparticles as antimicrobial agent: a case study on E. coli as a model for Gram-negative bacteria  

Microsoft Academic Search

The antimicrobial activity of silver nanoparticles against E. coli was investigated as a model for Gram-negative bacteria. Bacteriological tests were performed in Luria–Bertani (LB) medium on solid agar plates and in liquid systems supplemented with different concentrations of nanosized silver particles. These particles were shown to be an effective bactericide. Scanning and transmission electron microscopy (SEM and TEM) were used

Ivan Sondi; Branka Salopek-Sondi

2004-01-01

283

Elicitors and priming agents initiate plant defense responses  

Microsoft Academic Search

Biotic elicitors produced by plant pathogens or herbivore pests rapidly activate a range of plant chemical defenses when translocated to plant tissue. The fatty acid conjugate volicitin has proven to be a robust elicitor model for studying herbivore-induced plant defense responses. Here we review the role of insect-derived volicitin (N-[17-hydroxylinolenoyl]-L-glutamine) as an authentic elicitor of defense responses, specifically as an

Paul W. Pare ´; Mohamed A. Farag; Venkat Krishnamachari; Huiming Zhang; Choong-Min Ryu; Joseph W. Kloepper

2005-01-01

284

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

285

Non-streptomycete actinomycetes as biocontrol agents of soil-borne fungal plant pathogens and as plant growth promoters  

Microsoft Academic Search

Among soil microorganisms, bacteria and fungi and to a lesser extent actinomycetes, have received considerable attention as biocontrol agents of soil-borne fungal plant pathogens and as plant growth promoters. Within actinomycetes, Streptomyces spp. have been investigated predominantly, mainly because of their dominance on, and the ease of isolation from, dilution plates and because of the commercial interest shown on the

Khaled A. El-Tarabily; Krishnapillai Sivasithamparam

2006-01-01

286

Susceptibilities of Streptococcus pneumoniae and Haemophilus influenzae to 10 Oral Antimicrobial Agents Based on Pharmacodynamic Parameters: 1997 U.S. Surveillance Study  

PubMed Central

The susceptibilities of Streptococcus pneumoniae (1,476 strains) and untypeable Haemophilus influenzae (1,676 strains) to various oral ?-lactam, macrolide-azalide, and fluoroquinolone antimicrobial agents were determined by broth microdilution. Organisms were isolated from specimens obtained from outpatients in six geographic regions of the United States. MIC data were interpreted according to pharmacodynamically derived breakpoints applicable to the oral agents tested. Among H. influenzae strains, 41.6% were ?-lactamase positive. Virtually all H. influenzae strains were susceptible to amoxicillin-clavulanate (98%), cefixime (100%), and ciprofloxacin (100%), while 78% were susceptible to cefuroxime, 57% were susceptible to amoxicillin, 14% were susceptible to cefprozil, 9% were susceptible to loracarbef, 2% were susceptible to cefaclor, and 0% were susceptible to azithromycin and clarithromycin. Among S. pneumoniae isolates, 49.6% were penicillin susceptible, 17.9% were intermediate, and 32.5% were penicillin resistant, with penicillin MICs for 50 and 90% of the isolates tested of 0.12 and 4 ?g/ml, respectively. Overall, 94% of S. pneumoniae isolates were susceptible to amoxicillin and amoxicillin-clavulanate, 69% were susceptible to azithromycin and clarithromycin, 63% were susceptible to cefprozil and cefuroxime, 52% were susceptible to cefixime, 22% were susceptible to cefaclor, and 11% were susceptible to loracarbef. Although ciprofloxacin has marginal activity against S. pneumoniae, no high-level fluoroquinolone-resistant strains were found. Significant cross-resistance was found between penicillin and macrolides-azalides among S. pneumoniae isolates, with 5% of the penicillin-susceptible strains being macrolide-azalide resistant, compared with 37% of the intermediate isolates and 66% of the resistant isolates. Resistance was highest in S. pneumoniae isolates from patients younger than 10 years of age, middle ear and paranasal sinus specimens, and the southern half of the United States. With the continuing rise in resistance, judicious use of oral antimicrobial agents is necessary in all age groups. PMID:10428910

Jacobs, Michael R.; Bajaksouzian, Saralee; Zilles, Anne; Lin, Gengrong; Pankuch, Glenn A.; Appelbaum, Peter C.

1999-01-01

287

In vitro susceptibility to antimicrobial agents and ultrastructural characteristics related to swimming motility and drug action in Campylobacter jejuni and C. coli.  

PubMed

Campylobacter jejuni has recently been noted as the most common cause of bacterial food-borne diseases in Japan. In this study, we examined in vitro susceptibility to 36 antimicrobial agents of 109 strains of C. jejuni and C. coli isolated from chickens and patients with enteritis or Guillain-Barré syndrome from 1996 to 2009. Among these agents, carbapenems (imipenem, meropenem, panipenem, and biapenem) showed the greatest activity [minimal inhibitory concentration (MIC)(90), 0.03-0.125 microg/ml]. This was followed by sitafloxacin (MIC(90), 0.25 microg/ml), furazolidone and azithromycin (MIC(90), 0.5 microg/ml), gentamicin and clindamycin (MIC(90), 1 microg/ml), and clavulanic acid (beta-lactamase inhibitor; MIC(90), 2 microg/ml). All or most strains were resistant to aztreonam, sulfamethoxazole, and trimethoprim. Marked resistance was also observed for levofloxacin and tetracyclines. Resistance was not present for macrolides and rare for clindamycin. C. jejuni (and C. coli) exhibited high swimming motility and possessed a unique end-side (cup-like) structure at both ends, in contrast to Helicobacter pylori and Vibrio cholerae O1 and O139. The morphology of C. jejuni (and C. coli) changed drastically after exposure to imipenem (coccoid formation), meropenem (bulking and slight elongation), and sitafloxacin (marked elongation), and exhibited reduced motility. In the HEp-2 cell adherence model, unusually elongated bacteria were also observed for sitafloxacin. The data suggest that although resistance to antimicrobial agents (e.g., levofloxacin) has continuously been noted, carbapenems, sitafloxacin, and others such as beta-lactamase inhibitors alone showed good in vitro activity and that C. jejuni (and C. coli) demonstrated a unique ultrastructural nature related to high swimming motility and drug action. PMID:20225076

Yabe, Shizuka; Higuchi, Wataru; Takano, Tomomi; Razvina, Olga; Iwao, Yasuhisa; Isobe, Hirokazu; Yamamoto, Tatsuo

2010-06-01

288

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

289

Antimicrobial peptides from plants: stabilization of the ? core of a tomato defensin by intramolecular disulfide bond.  

PubMed

Cysteine-containing antimicrobial peptides of diverse phylogeny share a common structural signature, the ? core, characterized by a strong polarization of charges in two antiparallel ? sheets. In this work, we analyzed peptides derived from the tomato defensin SolyC07g007760 corresponding to the protein ? core and demonstrated that cyclization of the peptides, which results in segregation of positive charges to the turn region, produces peptides very active against Gram negative bacteria, such as Salmonella enterica and Helicobacter pylori. Interestingly, these peptides show very low hemolytic activity and thus represent a scaffold for the design of new antimicrobial peptides. PMID:23420649

Avitabile, C; Capparelli, R; Rigano, M M; Fulgione, A; Barone, A; Pedone, C; Romanelli, A

2013-04-01

290

Potential Antiosteoporotic Agents from Plants: A Comprehensive Review  

PubMed Central

Osteoporosis is a major health hazard and is a disease of old age; it is a silent epidemic affecting more than 200 million people worldwide in recent years. Based on a large number of chemical and pharmacological research many plants and their compounds have been shown to possess antiosteoporosis activity. This paper reviews the medicinal plants displaying antiosteoporosis properties including their origin, active constituents, and pharmacological data. The plants reported here are the ones which are commonly used in traditional medical systems and have demonstrated clinical effectiveness against osteoporosis. Although many plants have the potential to prevent and treat osteoporosis, so far, only a fraction of these plants have been thoroughly investigated for their physiological and pharmacological properties including their mechanism of action. An attempt should be made to highlight plant species with possible antiosteoporosis properties and they should be investigated further to help with future drug development for treating this disease. PMID:23365596

Jia, Min; Nie, Yan; Cao, Da-Peng; Xue, Yun-Yun; Wang, Jie-Si; Zhao, Lu; Rahman, Khalid; Zhang, Qiao-Yan; Qin, Lu-Ping

2012-01-01

291

Microwave Assisted Synthesis of 1-[5-(Substituted Aryl)-1H-Pyrazol-3-yl]-3,5-Diphenyl-1H-1,2,4-Triazole as Antinociceptive and Antimicrobial Agents  

PubMed Central

Purpose: An efficient technique has been developed for microwave assisted synthesis of 1-[5-(substituted aryl)-1H-pyrazol-3-yl]-3,5-diphenyl-1H-1,2,4-triazole as antinociceptive and antimicrobial agents. Methods: The desired compounds (S1-S10) were synthesized by the microwave irradiation via cyclization of formerly synthesized chalcones of 3,5-diphenyl-1H-1,2,4-triazole and hydrazine hydrate in mild acidic condition. All newly synthesized compounds were subjected to study their antinociceptive and antimicrobial activity. The analgesic potential of compounds was tested by acetic acid induced writhing response and hot plate method. The MIC values for antimicrobial activity were premeditated by liquid broth method. Results: The compounds S1, S2, S4, S6 and S10 were found to be excellent peripherally acting analgesic agents when tested on mice by acetic acid induced writhing method and compounds S3, S6 and S1 at dose level of 100 mg/kg were exhibited superior centrally acting antinociceptive activity when tested by Eddy’s hot plate method. In antimicrobial activity compound S10 found to be broad spectrum antibacterial agent at MIC value of 15.62 µg/ml and compound S6 was exhibited antifungal potential at 15.62 µg/mL on both fungal strains. Conclusion: Some novel pyrazoles clubbed with 1,2,4-triazole derivatives were synthesized and evaluated as possible antimicrobial, centrally and peripherally acting analgesics. PMID:24511473

Khanage, Shantaram Gajanan; Mohite, Popat Baban; Pandhare, Ramdas Bhanudas; Raju, S. Appala

2014-01-01

292

Identification of a Vibrio strain producing antimicrobial agents in the excretory organs of Nautilus pompilius (Cephalopoda: Nautiloidea)  

Microsoft Academic Search

The aim of the present study was to identify and characterize bacteria producing antimicrobial compounds in the excretory\\u000a organs of Nautilus pompilius. Culture-dependent and culture-independent complementary approaches were used for bacterial identification such as: culture\\u000a on selective media, Gram staining, CARD-FISH, direct DNA extraction from host tissue, PCR amplification and sequencing of\\u000a the bacterial 16S rRNA gene. Results show presence

M. Pernice; D. Destoumieux-Garzón; J. Peduzzi; S. Rebuffat; R. Boucher-Rodoni

2007-01-01

293

Assessment of long-term storage on antimicrobial and cyclooxygenase-inhibitory properties of South African medicinal plants.  

PubMed

In traditional medicine, plant materials are often stored by traditional healers, plant gatherers and traders before they are eventually consumed or sold. The critical point is whether stored medicinal plants are as active as freshly harvested dried material. We evaluated the effects of long-term storage (12 or 16?years) on the antimicrobial (microplate dilution method) and anti-inflammatory (COX-1 and COX-2 inhibition) potencies of 21 extensively used traditional medicinal plants in treating pain and infection-related ailments. The minimum inhibitory concentration (MIC) values obtained against Staphylococcus aureus and Pseudomonas aeruginosa in the stored plant materials were generally either lower or roughly the same as in the fresh material. Most of the stored plant material had comparable minimum microbicidal concentration (MMC) values as the fresh material against S. aureus and P. aeruignosa. Similarly, the majority (71%) of the stored plant material had similar MIC and/or MMC values as fresh material against the fungus Candida albicans. The percentage inhibition of COX-1 by the majority (88%) of the stored material was not significantly different when compared to those freshly collected. Stored material of Clausena anisata, Ekebergia capensis and Trichilia dregeana showed a significantly higher COX-1 inhibition than the fresh material. The therapeutic and conservation implications of the results are discussed. PMID:22933443

Amoo, Stephen O; Aremu, Adeyemi O; Moyo, Mack; Van Staden, Johannes

2013-07-01

294

Studies on Antimicrobial Efficiency of Citrullus colocynthis (L.) Schrad: A Medicinal Plant  

Microsoft Academic Search

In the present study antimicrobial efficiency of Citrullus colocynthis (L.) Schrad was studied on seven bacteria Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris, Pseudomonas aeruginosa, Salmonella typhi and Staphylococcus aureus. Ethanol, chloroform and petroleum ether extracts were used for antibacterial assay. Growth inhibitions were evaluated by the disc diffusion method. Ethanol extract is more active against Escherichia coli, Proteus

John Peter Paul J

2008-01-01

295

Danish Integrated Antimicrobial Resistance Monitoring and Research Program  

PubMed Central

Resistance to antimicrobial agents is an emerging problem worldwide. Awareness of the undesirable consequences of its widespread occurrence has led to the initiation of antimicrobial agent resistance monitoring programs in several countries. In 1995, Denmark was the first country to establish a systematic and continuous monitoring program of antimicrobial drug consumption and antimicrobial agent resistance in animals, food, and humans, the Danish Integrated Antimicrobial Resistance Monitoring and Research Program (DANMAP). Monitoring of antimicrobial drug resistance and a range of research activities related to DANMAP have contributed to restrictions or bans of use of several antimicrobial agents in food animals in Denmark and other European Union countries. PMID:18217544

Heuer, Ole E.; Emborg, Hanne-Dorthe; Bagger-Skj?t, Line; Jensen, Vibeke F.; Rogues, Anne-Marie; Skov, Robert L.; Agers?, Yvonne; Brandt, Christian T.; Seyfarth, Anne Mette; Muller, Arno; Hovgaard, Karin; Ajufo, Justin; Bager, Flemming; Aarestrup, Frank M.; Frimodt-M?ller, Niels; Wegener, Henrik C.; Monnet, Dominique L.

2007-01-01

296

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

297

Antimicrobial resistance of integron-harboring Escherichia coli isolates from clinical samples, wastewater treatment plant and river water.  

PubMed

The presence and persistence of antibiotic resistant bacteria in the environment is thought to be a growing threat to public health. The route of the spread of multiresistant bacteria from human communities to aquatic environment may lead through wastewater treatment plants that release treated wastewater to a water reservoir. In this study we used multiplex PCR assay to determine the frequency of integron presence in Escherichia coli isolates cultured from wastewater treatment plant (WWTP) (integrons were detected in 11% of E. coli isolates), river water upstream (6%) and downstream (14%) the discharge of WWTP, and clinical specimens (56%). Antimicrobial resistance of the integron-positive isolates, determined by disk diffusion method, varied between E. coli of different origin. Isolates from the downstream river, compared to those cultured from upstream river, were more frequently resistant to kanamycin, cephalotin, co-trimoxazole, trimethoprim, and fluoroquinolones. Moreover, they displayed broader resistance ranges, expressed as the number of classes of antimicrobials to which they were resistant. The results may suggest that WWTP effluent contributes to increased frequency of integron-positive E. coli isolates in the river downstream the WWTP and to their elevated resistance level. PMID:22119028

Koczura, Ryszard; Mokracka, Joanna; Jab?o?ska, Lucyna; Gozdecka, Edyta; Kubek, Martyna; Kaznowski, Adam

2012-01-01

298

Resistance of Staphylococcus aureus to the cationic antimicrobial agent poly(2-(dimethylamino ethyl)methacrylate) (pDMAEMA) is influenced by cell-surface charge and hydrophobicity.  

PubMed

Cationic antimicrobial agents may prevent device-associated infections caused by Staphylococcus epidermidis and Staphylococcus aureus. This study reports that the cationic antimicrobial polymer poly(2-(dimethylamino ethyl)methacrylate) (pDMAEMA) was more effective at antagonizing growth of clinical isolates of S. epidermidis than of S. aureus. Importantly, mature S. epidermidis biofilms were significantly inactivated by pDMAEMA. The S. aureus isolates tested were generally more hydrophobic than the S. epidermidis isolates and had a less negative charge, although a number of individual S. aureus and S. epidermidis clinical isolates had similar surface hydrophobicity and charge values. Fluorescence spectroscopy and flow cytometry revealed that fluorescently labelled pDMAEMA interacted strongly with S. epidermidis compared with S. aureus. S. aureus ?dltA and ?mprF mutants were less hydrophobic and therefore more susceptible to pDMAEMA than wild-type S. aureus. Although the different susceptibility of S. epidermidis and S. aureus isolates to pDMAEMA is complex, influenced in part by surface hydrophobicity and charge, these findings nevertheless reveal the potential of pDMAEMA to treat S. epidermidis infections. PMID:21393458

Rawlinson, Lee-Anne B; O'Gara, James P; Jones, David S; Brayden, David J

2011-07-01

299

[Use of the gene of antimicrobial peptide cecropin P1 for producing marker-free transgenic plants].  

PubMed

The marker-free transgenic tobacco plants carrying a synthetic gene encoding the antimicrobial peptide cecropin P1 (cecP1) under the control of the cauliflower mosaic virus 35S RNA promoter were produced. The binary vector pBM, free of any selective genes of resistance to antibiotics or herbicides intended for selecting transgenic plants, was used for transformation. The transformants were screened on a nonselective medium by detecting cecropin P1 in plant cells according to the antibacterial activity of plant extracts and enzyme immunoassay. According to the two used methods, 2% of the analyzed regenerants were transformants. The resulting marker-free plants displayed a considerably increased resistance to microbial phytopathogens-the bacterium Erwinia carotovora and fungus Sclerotinia sclerotiorum. Thus, the gene cecP1 can be concurrently used as a target gene and a screening marker. The utility of cecP1 as a selective gene for direct selection of transformed plants is discussed. PMID:19769295

Zakharchenko, N S; Pigoleva, S V; Iukhmanova, A A; Bur'ianova, Ia I

2009-08-01

300

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

301

[Transgenic Belarussian-bred potato plants expressing genes for antimicrobial peptides of the cecropin-melittin type].  

PubMed

Binary vectors for Agrobacterium-mediated transformation were constructed to express the genes for antimicrobial peptides (APs) of the cectropin-melittin type under the control of the cauliflower mosaic virus 35S RNA promoter in plants. It was shown with Escherichia coli and Agrobacterium tumefaciens cells that the cassettes could be cloned in pB1121-based vectors with deletion of the 3-D-glycuronidase gene only in the orientation opposite to that of the original vector. Transgenic potato plants were obtained using the Belarussian varieties Odyssey, Vetraz, and Scarb. Their cells expressed the MsrA1 or CEMA peptides of the cecropin-melittin type. The expression was shown to confer higher resistance to bacterial (Erwinia carotovora) infection and extremely high resistance to fungal (Phytophtora infestans and Alternarla solani) infections. PMID:21434415

Vutto, N L; Gapeeva, T A; Pundik, A N; Tret'iakova, T G; Volotovski?, I D

2010-12-01

302

Systematic Screening of Plant Extracts from the Brazilian Pantanal with Antimicrobial Activity against Bacteria with Cariogenic Relevance.  

PubMed

This study proposes a bioprospection methodology regarding the antimicrobial potential of plant extracts against bacteria with cariogenic relevance. Sixty extracts were obtained from ten plants - (1) Jatropha weddelliana, (2) Attalea phalerata, (3) Buchenavia tomentosa, (4) Croton doctoris, (5) Mouriri elliptica, (6) Mascagnia benthamiana, (7) Senna aculeata, (8) Unonopsis guatterioides, (9) Allagoptera leucocalyx and (10) Bactris glaucescens - using different extraction methods - (A) 70° ethanol 72 h/25°C, (B) water 5 min/100°C, (C) water 1 h/55°C, (D) water 72 h/25°C, (E) hexane 72 h/25°C and (F) 90° ethanol 72 h/25°C. The plants were screened for antibacterial activity at 50 mg/ml using the agar well diffusion test against Actinomyces naeslundii ATCC 19039, Lactobacillus acidophilus ATCC 4356, Streptococcus gordonii ATCC 10558, Streptococcus mutans ATCC 35688, Streptococcus sanguinis ATCC 10556, Streptococcus sobrinus ATCC 33478 and Streptococcus mitis ATCC 9811. The active extracts were tested to determine their minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), cytotoxicity and chemical characterization. Forty-seven extracts (78%) were active against at least one microorganism. Extract 4A demonstrated the lowest MIC and MBC for all microorganisms except S. gordonii and the extract at MIC concentration was non-cytotoxic. The concentrated extracts were slightly cytotoxic. Electrospray ionization with tandem mass spectrometry analyses demonstrated that the extract constituents coincided with the mass of the terpenoids and phenolics. Overall, the best results were obtained for extraction methods A, B and C. The present work proved the antimicrobial activity of several plants. Particularly, extracts from C. doctoris were the most active against bacteria involved in dental caries disease. © 2014 S. Karger AG, Basel. PMID:24603299

Brighenti, F L; Salvador, M J; Delbem, Alberto Carlos Botazzo; Delbem, Adina Cleia Bottazzo; Oliveira, M A C; Soares, C P; Freitas, L S F; Koga-Ito, C Y

2014-01-01

303

In vivo assessment of antimicrobial agents against Toxoplasma gondii by quantification of parasites in the blood, lungs, and brain of infected mice.  

PubMed Central

The in vivo effects of antimicrobial agents against Toxoplasma gondii were evaluated in mice that were infected intraperitoneally with 10(4) tachyzoites of the RH strain by determination of survival rates and study of the kinetics of growth of T. gondii in infected mice. At various intervals after infection, subcultures of serial dilutions of blood, lung, and brain homogenates were performed in fibroblast tissue cultures for determination of parasitic loads. Pyrimethamine (18.5 mg/kg per day), sulfadiazine (375 mg/kg per day), and clindamycin (300 mg/kg per day) were administered for 10 days from day 1 or day 4 after infection. Untreated control mice died within 9 days and showed early and predominant lung involvement. All mice treated with sulfadiazine administered from day 1 survived and were apparently healthy; parasitic loads decreased early after treatment, but a relapse was observed 5 days after the cessation of therapy. When pyrimethamine was administered from day 1, 7 of 11 mice died within 25 days; by determination of parasitic loads, the effect of pyrimethamine was only demonstrable from day 6, and a relapse was constantly observed after the cessation of therapy. When pyrimethamine and sulfadiazine were administered in combination, 100% of mice survived; when therapy was started at day 1, parasites remained undetectable; in mice treated from day 4, parasites were eradicated by day 8 but infection relapsed 8 days after the cessation of therapy. All mice treated with clindamycin from day 1 or day 4 died within 10 days, but parasitemia was always undetectable. These results indicate that study of the kinetics of parasitic loads in blood and organs may provide additional information on the effect of antimicrobial agents against T. gondii in regard to the evolution of the infection and may represent a reliable basis for the determination of therapeutic regimens in humans. PMID:2221854

Piketty, C; Derouin, F; Rouveix, B; Pocidalo, J J

1990-01-01

304

Synthesis, characterization and biological evaluation of some novel 2,4-thiazolidinediones as potential cytotoxic, antimicrobial and antihyperglycemic agents.  

PubMed

A series of some novel 2,4-thiazolidinediones (TZDs) (2a-x) have been synthesized and characterized by FTIR, (1)H NMR, (13)C NMR and LC mass spectral analysis. All the synthesized compounds were evaluated for their cytotoxicity, antimicrobial and in vivo antihyperglycemic activities. Among the tested compounds for cytotoxicity using Brine Shrimp Lethality assay, compound 2t ((Z)-5-(4-((E)-3-oxo-3-(thiophen-2-yl)prop-1-enyl)benzylidene)-1,3-thiazolidine-2,4-dione) exhibited significant inhibitory activity at ED(50) value 4.00±0.25 ?g/mL and this level of activity was comparable to that of the reference drug podophyllotoxin with ED(50) value 3.61±0.17 ?g/mL. Antimicrobial activity was screened using agar well diffusion assay method against selected Gram-positive, Gram-negative and fungal strains and the activity expressed as the minimum inhibitory concentration (MIC) in ?g/mL. From the results of antimicrobial activity compound 2s ((Z)-5-(4-((E)-3-(3,5-bis(benzyloxy)phenyl)-3-oxoprop-1-enyl)benzylidene)-1,3-thiazolidine-2,4-dione) was found to be the most active against all the tested strains of microorganisms with MIC value 16 ?g/mL. In vivo antihyperglycemic effect of twenty four TZDs (2a-x) at different doses 10, 30 and 50mg/kg b.w (oral) were assessed using percentage reduction of plasma glucose (PG) levels in streptozotocin-induced type II diabetic rat models. From the results, the novel compound 2x ((Z)-5-(4-((E)-3-(9H-fluoren-2-yl)-3-oxoprop-1-enyl)benzylidene)-1,3-thiazolidine-2,4-dione) exhibited considerably potent blood glucose lowering activity than that of the standard drug rosiglitazone and it could be a remarkable starting point to evaluate structure-activity relationships and to develop new lead molecules with potential cytotoxicity, antimicrobial and antihyperglycemic activities. In addition molecular docking studies were carried out against PPAR? molecular target using Molegro Virtual Docker v 4.0 to accomplish preliminary confirmation of the observed in vivo antihyperglycemic activity. PMID:22981328

Avupati, Vasudeva Rao; Yejella, Rajendra Prasad; Akula, Annapurna; Guntuku, Girija Sankar; Doddi, Bhagya Raju; Vutla, Venkata Rao; Anagani, Suvarna Ratna; Adimulam, Lakshmana Santhi; Vyricharla, Aruna Kumar

2012-10-15

305

[Antimicrobial prophylaxis in urological surgery].  

PubMed

The present review is dedicated to the problem of perioperative antimicrobial prophylaxis in urological surgery. There are considered modern guidelines for perioperative antimicrobial prophylaxis in urology. There are discussed; aims, timing, and duration of perioperative antimicrobial prophylaxis, risk factors of postoperative infections in urological surgery, pharmacological properties of major antimicrobial drugs, selection and route of administration of antibacterial agents. There are presented the recommendations of perioperative antimicrobial prophylaxis for the varies types of urological surgery, as well as, are given in detail the recommendations about clinical uses of antibiotics for the different types of urological interventions. There are concluded, that perioperative antimicrobial prophylaxis reduces risk of postoperative infections in urological surgery, but sometimes this prophylaxis is not effective and the problem of perioperative antimicrobial prophylaxis in urology is debatable at present. It is necessary continues search of optimal methods of of perioperative antimicrobial prophylaxis in urology. These review are designed for urologists and clinical pharmacologists. PMID:17660605

Antelava, N A; Pirtskhala?shvili, N N; Antelava, A V; Pachkoriia, K Z

2007-06-01

306

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

307

Induction of Defense Responses in Cucumber Plants (Cucumis sativus L.) by the Biocontrol Agent Trichoderma harzianum  

Microsoft Academic Search

The potential of the biocontrol agent Trichoderma harzianum T-203 to trigger plant defense responses was investigated by inoculating roots of cucumber seedlings with Trichoderma in an aseptic, hydroponic system. Trichoderma-treated plants were more developed than nontreated plants throughout the experiment. Electron microscopy of ultrathin sections from Trichoderma-treated roots revealed penetration of Trichoderma into the roots, restricted mainly to the epidermis

I. YEDIDIA; N. BENHAMOU; I. CHET

1999-01-01

308

Synthesis, characterization and in vitro biological evaluation of some novel diarylsulfonylureas as potential cytotoxic and antimicrobial agents.  

PubMed

A series of novel diarylsulfonylureas (1-28) have been synthesized and characterized by FTIR, (1)H NMR, (13)C NMR and LC mass spectral analysis. All the synthesized compounds were evaluated for their in vitro cytotoxicity and antimicrobial activities. Among the tested compounds for cytotoxicity using Brine Shrimp Lethality assay, compounds 18 and 22 exhibited significant cytotoxicity at ED(50) values 3.96±0.21 and 4.02±0.19?g/mL, respectively. This level of activity was found comparable to that of the reference drug podophyllotoxin with ED(50) value 3.61±0.17?g/mL and it could be a remarkable starting point to develop new lead molecules with major cytotoxicity. Antimicrobial activity was screened using agar well diffusion assay method against selected Gram-positive, Gram-negative and fungal strains. Most of the compounds showed promising antibacterial and antifungal activity and the activity expressed as the minimum inhibitory concentration (MIC) in ?g/mL. PMID:22200598

Avupati, Vasudeva Rao; Yejella, Rajendra Prasad; Guntuku, Girijasankar; Gunta, Pradeepsagar

2012-01-15

309

Antibiotic Conjugated Fluorescent Carbon Dots as a Theranostic Agent for Controlled Drug Release, Bioimaging, and Enhanced Antimicrobial Activity  

PubMed Central

A novel report on microwave assisted synthesis of bright carbon dots (C-dots) using gum arabic (GA) and its use as molecular vehicle to ferry ciprofloxacin hydrochloride, a broad spectrum antibiotic, is reported in the present work. Density gradient centrifugation (DGC) was used to separate different types of C-dots. After careful analysis of the fractions obtained after centrifugation, ciprofloxacin was attached to synthesize ciprofloxacin conjugated with C-dots (Cipro@C-dots conjugate). Release of ciprofloxacin was found to be extremely regulated under physiological conditions. Cipro@C-dots were found to be biocompatible on Vero cells as compared to free ciprofloxacin (1.2?mM) even at very high concentrations. Bare C-dots (?13?mg?mL?1) were used for microbial imaging of the simplest eukaryotic model—Saccharomyces cerevisiae (yeast). Bright green fluorescent was obtained when live imaging was performed to view yeast cells under fluorescent microscope suggesting C-dots incorporation inside the cells. Cipro@C-dots conjugate also showed enhanced antimicrobial activity against both model gram positive and gram negative microorganisms. Thus, the Cipro@C-dots conjugate paves not only a way for bioimaging but also an efficient new nanocarrier for controlled drug release with high antimicrobial activity, thereby serving potential tool for theranostics. PMID:24744921

Patil, Vaibhav; Khade, Monika; Goshi, Ekta; Sharon, Madhuri

2014-01-01

310

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

311

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

312

Bioactive chemical constituents and comparative antimicrobial activity of callus culture and adult plant extracts from Alternanthera tenella.  

PubMed

Crude extracts of a callus culture (two culture media) and adult plants (two collections) from Alternanthera tenella Colla (Amaranthaceae) were evaluated for their antibacterial and antifungal activity, in order to investigate the maintenance of antimicrobial activity of the extracts obtained from plants in vivo and in vitro. The antibacterial and antifungal activity was determined against thirty strains of microorganisms including Gram-positive and Gram-negative bacteria, yeasts and dermatophytes. Ethanolic and hexanic extracts of adult plants collected during the same period of the years 1997 and 2002 [Ribeirăo Preto (SP), collections 1 and 2] and obtained from plant cell callus culture in two different hormonal media (AtT43 and AtT11) inhibited the growth of bacteria, yeasts and dermatophytes with inhibition halos between 6 and 20 mm. For the crude extracts of adult plants bioassay-guided fractionation, purification, and isolation were performed by chromatographic methods, and the structures of the isolated compounds were established by analysis of chemical and spectral evidences (UV, IR, NMR and ES-MS). Steroids, saponins and flavonoids (aglycones and C-glycosides) were isolated. The minimum inhibitory concentration (MIC) of the isolated compounds varied from 50 to 500 microg/mL. PMID:19678541

Salvador, Marcos J; Pereira, Paulo S; França, Suzelei C; Candido, Regina C; Ito, Izabel Y; Dias, Diones A

2009-01-01

313

[Adaptation study for biofilm of the urinary tract via highly complicated bladder model (biofilm model of the urinary tract)--experimental study using automatic simulator of the urinary antimicrobial agent concentration].  

PubMed

With the view of making an adaptation study for biofilm of the urinary tract, we devised a computer-controlled highly complicated bladder model (biofilm model of the urinary tract) that allowed the simulation of time-course changes in the urinary concentration of antimicrobial agents. Clarithromycin (CAM), which is reported to have an anti-biofilm action, was examined at urinary levels approximating clinical concentrations and its effect on biofilm was determined. The following results were obtained. 1) Ofloxacin (OFLX, 200 mg x 2/day, MIC; 8 micrograms/ml), which is active against Pseudomonas aruginosa, caused apparent microbial elimination from the model at 42 hours, but bacterial regrowth occurred 4 hours after withdrawal of this agent. No disappearance of the biofilm was noted with OFLX suggesting that this was the cause of bacterial regrowth. 2) The combination of OFLX (200 mg x 2/day) and CAM (MIC; > 128 micrograms/ml, 200 mg x 2/day) on anti-biofilm agent, with no effect on P. aeruginosa, eliminated bacteria from the bladder model more rapidly and prolonged the regrowth time to 10 hours after withdrawal of the antimicrobial agents. Disappearance of most of the biofilm and only slight microbial adhesion was noted. 3) The combination of OFLX (200 mg x 2/day) and CAM (400 mg x 3/day) caused microbial elimination from the bladder model with no regrowth at 30 hours after withdrawal of the antimicrobial agents. The biofilm disappeared completely and no microbial adhesion was noted. 4) CAM alone (400 mg x 3/day) allowed microbial recovery to the initial level within 48 hours after withdrawal, but led to disappearance of the biofilm and the adhesion of microbes without a glycocalyx. 5) These results suggest that the anti-biofilm action of CAM is dose-dependent, and that combined use of an appropriate antimicrobial agent and anti-biofilm agent like CAM may be effective for biofilm infections of the urinary tract. PMID:8089557

Sano, M; Kumamoto, Y; Nishimura, M; Hirose, T; Ohya, S

1994-07-01

314

Occurrence of anabolic agents in plants and their importance.  

PubMed

More than 40 plant species have been shown to contain substances that are active in biological assays for estrogenic activity. Such substances may be constitutive metabolic products of a plant, or be formed adaptively in response to environmental factors, such as fungal attack (e.g. coumestrol synthesis in alfalfa infected with Pseudopeziza medicagensis); in other instances estrogens may arise from microbial attack on plant material during storage (e.g. zearalenone formation from corn by Fusarium spp.) Phyto-estrogens may reach man through direct consumption of fresh fruit, vegetables and processed plant products (e.g. administration of olive or cornoil can induce vaginal keratinization in post-menopausal women); or---more relevant to this Symposium---by consumption of carcasses and products from animals fed estrogen-containing forage. Important pasture and forage plants shown to contain phyto-oestrogens include Trifolium subterraneum L, notably the cultivars Dwalganup, Mt. Barker, Yarloop and Marrar, T. pratense (red clover), T. fragiferum L. (strawberry clover), T. alexandrinum (berseem clover), Medicago sativa (alfalfa or lucerne) and Soya hispida (soya beans). A beneficial anabolic action of the estrogens contained in these plants has been implied, but not unequivically established. More attention has been paid to their noxious effects on livestock. On affected T. subterraneum pasture, castrated male sheep showed lactation, squamous metaplasia of the bulbo-urethral glands and urethral stenosis; infertility, variously attributed to suppression of gonadotrophin release and ovulation; faulty ovum transport; premature regression of corpora lutea; irreversible cystic hyperplasia of endometrial glands on prolonged exposure; dystocia and prolapse of the uterus. Sporadic incidence of phyto-estrogen induced infertility in cattle has been reported, attended by ovarian cyst formation. Estrogenic activity in forage plants has been reported from Australia, New Zealand, India, Sweden, Great Britain, Germany, Denmark, Holland, Finland, Egypt and Israel. The clover constituents chiefly incriminated for these effects are glycosides of the isoflavone derivatives genistein and its 4'-methyl ether biochanin-A, daidzein and its 4'-methyl ether formononetin, and pratensein; coumestrol and its 3'- and 4'-methyl ethers account for the estrogenic activity of alfalfa. The isoflavone content of subterranean clover may reach 3 percent of its dry weight, and the coumestrol content of lucerne may exceed 100 mug/g. Coumestrol and genistein compete with 17beta-estradiol for binding sites on the uterine cytoplasmic receptor and induce macromolecular synthesis in the uterus, but fail to induce ovum implantation in ovariectomized, gestagen-maintained rats. Uterotrophic activity of coumestrol and genistein given parenterally to sheep is approximately 10(-3) and 10(-5) times that of stilboestrol, respectively. Biological activity of ingested phytoestrogens is modified by ruminal micro-organisms and hepatic metabolism... PMID:1066275

Lindner, H R

1976-01-01

315

Antimicrobial peptides  

PubMed Central

Complicated schemes of classical breeding and their drawbacks, environmental risks imposed by agrochemicals, decrease of arable land, and coincident escalating damages of pests and pathogens have accentuated the necessity for highly efficient measures to improve crop protection. During co-evolution of host-microbe interactions, antimicrobial peptides (AMPs) have exhibited a brilliant history in protecting host organisms against devastation by invading pathogens. Since the 1980s, a plethora of AMPs has been isolated from and characterized in different organisms. Nevertheless the AMPs expressed in plants render them more resistant to diverse pathogens, a more orchestrated approach based on knowledge of their mechanisms of action and cellular targets, structural toxic principle, and possible impact on immune system of corresponding transgenic plants will considerably improve crop protection strategies against harmful plant diseases. This review outlines the current knowledge on different modes of action of AMPs and then argues the waves of AMPs' ectopic expression on transgenic plants' immune system. PMID:21847025

2011-01-01

316

Chemicals as peak shaving agents in IGCC based power plants  

SciTech Connect

Coal gasification generates a very impure synthesis gas, which before use in gas turbines for Integrated Gasification Combined Cycle (IGCC) plants has to be cleaned thoroughly. The purification of such a gas may be done by hot gas cleaning to a level which allows the gas to be used for production of chemicals such as methanol or dimethyl ether (DME). Such a production may be attractive either for use of the substances as such in the chemical industry or as automotive fuels. Alternatively these fuels may also be used as gas turbine fuels for power production. In the latter case an interesting possibility exists in the form of chemical recuperation. Low grade heat is used in the catalytically based transformation of methanol or DME into hydrogen and carbon monoxide. The present paper deals with the hot gas cleaning processes and the catalytic processes involved in a power plant in which the produced methanol and/or DME is used for peak shaving purposes.

Hansen, J.B.; Aasberg-Petersen, K.; Sigurdardottir, D.; Nielsen, H. [Haldor Topsoe A/S (Denmark)

1998-12-31

317

Antimicrobial specificity and mechanism of action of disulfide-removed linear analogs of the plant-derived Cys-rich antimicrobial peptide Ib-AMP1.  

PubMed

Ib-AMP1 is a 20-residue disulfide-linked beta-sheet antimicrobial peptide found in the seeds of Impatiens balsamina. In order to investigate the effects of the 2 disulfide bonds on the antimicrobial specificity, to determine the mechanism of antimicrobial action of Ib-AMP1 and to develop novel cell-selective antimicrobial peptides with improved antimicrobial specificity as compared to wild-type Ib-AMP1, we synthesized a disulfide-removed linear analog of Ib-AMP1 with L-Pro, D-Pro or peptoid residues (Nala and Nlys) at the central position of the molecule. All linear analogs displayed a 3.7-4.8-fold higher antimicrobial specificity than wild-type Ib-AMP1, indicating that the disulfide bonds of Ib-AMP1 analogs are not essential for its antimicrobial specificity. Circular dichroism spectra revealed that the peptoid residues, as well as the proline at the central position of disulfide bond-removed Ib-AMP1 analogs, induce a beta-turn structure in a negatively charged bacterial membrane-mimicking environment. Ib-AMP1 was not effective in depolarizing the cytoplasmic membranes of Staphylococcus aureus and showed almost no leakage of calcein from negatively charged bacterial membranes mimicking lipid vesicles. In contrast, all linear analogs caused very weak dye leakage from negatively charged vesicles, but they almost completely depolarized the membrane potential of S. aureus cells. Collectively, our results suggest that the target of Ib-AMP1 may not be the cytoplasmic membranes of bacteria but their intracellular components. All linear analogs exhibit lethality due to their ability to form small channels that permit the transit of ions or protons and not molecules as large as calcein, and not by disrupting membranes. PMID:19778562

Wang, Peng; Bang, Jeong-Kyu; Kim, Hak Jun; Kim, Jin-Kyoung; Kim, Yangmee; Shin, Song Yub

2009-12-01

318

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

319

Novel Ethyl 1,5-Disubstituted-1H-Pyrazole-3-Carboxylates as a New Class of Antimicrobial Agents.  

PubMed

Abstract A series of pyrazole derivatives 9-22 were designed and synthesized. All the newly synthesized compounds were assayed for their antimicrobial activity against the Grampositive bacteria Staphyllococcus aureus and Bacillius subtilis and the Gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa, in addition to the fungi organisms, Candida albicans, C. parapsilosis and C. tropicalis. Ethyl 5-(2,5-dimethylthiophen- 3-yl)-1-phenyl-1H-pyrazole-3-carboxylate (21) (MICE.coli = 0.038 ?mol mL-1, MICP. aerug. = 0.067 ?mol mL-1) is nearly as active as ampicillin (MIC = 0.033 and 0.067 ?mol mL-1), respectively. Ethyl 5-(4-bromo-2-chlorophenyl)- 1-phenyl-1H-pyrazole-3-carboxylate (16) (MIC = 0.015 ?mol mL-1) is more active than fluconazole (0.020 ?mol mL-1) as a reference drug against C. parapsilosis. PMID:25296679

Radwan, Awwad A; Ghorab, Mostafa M; Alsaid, Mansour S; Alanazi, Fares K

2014-09-01

320

Laurene-type sesquiterpenes from the Red Sea red alga Laurencia obtusa as potential antitumor-antimicrobial agents.  

PubMed

Three new laurene-type sesquiterpenes, 12-hydroxy isolaurene (1), 8,11-dihydro-12-hydroxy isolaurene (2) and isolauraldehyde (3) were isolated from the organic extract of the red alga Laurencia obtusa. The chemical structures of isolates were determined by interpretation of their spectral data 1D and 2D NMR, UV, IR and MS. The newly isolated compounds were tested for their antimicrobial and antitumor activities. Compounds (1-3) exhibited potent activity against the gram-positive Bacillus subtilis and Staphylococcus aureus, where 3 proved to be the most active (MIC 35 and 27 ?g/mL, respectively). Moreover, compound 3 exhibited a significant activity against Candida albicans (MIC of 70 ?g/mL) and revealed to have very promising activity in an in vitro model of Ehrlich ascites Carcinoma. PMID:22819506

Alarif, Walied M; Al-Lihaibi, Sultan S; Ayyad, Seif-Eldin N; Abdel-Rhman, Mohamed H; Badria, Farid A

2012-09-01

321

Novel cationic quinazolin-4(3H)-one conjugated fullerene nanoparticles as antimycobacterial and antimicrobial agents.  

PubMed

A series of novel cationic fullerene derivatives bearing a substituted-quinazolin-4(3H)-one moiety as a side arm were synthesized using the 1,3-dipolar cycloaddition reaction of C60 with azomethine ylides generated from the corresponding Schiff bases of substituted quinazolinones. The synthesized compounds 5a-f were characterized by elemental analysis, FT-IR, 1H NMR, 13C NMR, and ESI-MS and screened for their antibacterial activity against Mycobacterium tuberculosis (H37RV) and antimicrobial activity against selected Gram-positive (Staphylococcus aureus and S. pyogenes) and Gram-negative (Pseudomonas aeruginosa, Klebsiella pneumonia and Escherichia coli) bacterial and fungal strains (Candida albicans, Aspergillus clavatus, and A. niger), respectively. All the compounds exhibited significant activity, with the most effective compounds having MIC values and zones of inhibition comparable to those of standard drugs. PMID:23359525

Patel, Manishkumar B; Harikrishnan, Uma; Valand, Nikunj N; Modi, Nishith R; Menon, Shobhana K

2013-03-01

322

Contrasting effects of two antimicrobial agents (triclosan and triclocarban) on biomineralisation of an organophosphate pesticide in soils.  

PubMed

We examined the impact of triclosan (TCS) and triclocarban (TCC) antimicrobial compounds on the biomineralisation of glucose and cadusafos pesticide in three Australian soils. Mineralisations of radiolabelled ((14)C) compounds were measured over a period of up to 77 d in sterile and non-sterile soils treated with different concentrations of TCS and TCC (0-450 mg kg(-1)). The rates of mineralisation of cadusafos were found to decrease with increasing concentration of TCS in all soils, but varied with soil type. Soils treated with TCS at the highest concentration (270 mg kg(-1)) reduced cadusafos mineralisation by up to 58%. However, glucose mineralisation was not significantly affected by the presence of TCS. While TCS, significantly reduced the mineralisation of cadusafos (by 17%; p<0.05) even at the lowest studied concentration (30 mg kg(-1)), no significant effect of TCC was observed on cadusafos or glucose mineralisation even at the highest concentration used (450 mg kg(-1)). PMID:24461429

Kookana, R S; Ali, A; Smith, L; Arshad, M

2014-07-01

323

Antimicrobial peptides: promising compounds against pathogenic microorganisms.  

PubMed

In the last decades, the indiscriminate use of conventional antibiotics has generated high rates of microbial resistance. This situation has increased the need for obtaining new antimicrobial compounds against infectious diseases. Among these, antimicrobial peptides (AMPs) constitute a promising alternative as therapeutic agents against various pathogenic microbes. These therapeutic agents can be isolated from different organisms, being widespread in nature and synthesized by microorganisms, plants and animals (both invertebrates and vertebrates). Additionally, AMPs are usually produced by a non-specific innate immune response. These peptides are involved in the inhibition of cell growth and in the killing of several microorganisms, such as bacteria, fungi, enveloped viruses, protozoans and other parasites. They have many interesting properties as potential antibiotics, such as relatively small sizes (below 25-30 kDa), amphipathic structures, cationic nature, and offer low probability for the generation of microbial resistance. In recent years, many novel AMPs, with very promising therapeutic properties, have been discovered. These peptides have been the base for the production of chemical analogs, which have been designed, chemically synthesized and tested in vitro for their antimicrobial activity. This review is focused on antibacterial (against Gram (-) and Gram (+) bacteria) and antifungal peptides, discussing action mode of AMPs, and recent advances in the study of the molecular basis of their anti-microbial activity. Finally, we emphasize on their current pharmacological development, future directions and applications of AMPs as promising antibiotics of therapeutic use for microbial infections. PMID:24533812

Cruz, J; Ortiz, C; Guzmán, F; Fernández-Lafuente, R; Torres, R

2014-01-01

324

Evolutionary history of synthesis pathway genes for phloroglucinol and cyanide antimicrobials in plant-associated fluorescent pseudomonads.  

PubMed

Plant-beneficial fluorescent Pseudomonas spp. play important ecological roles. Here, their evolutionary history was investigated by a multilocus approach targeting genes involved in synthesis of secondary antimicrobial metabolites implicated in biocontrol of phytopathogens. Some of these genes were proposed to be ancestral, and this was investigated using a worldwide collection of 30 plant-colonizing fluorescent pseudomonads, based on phylogenetic analysis of 14 loci involved in production of 2,4-diacetylphloroglucinol (phlACBDE, phlF, intergenic locus phlA/phlF), hydrogen cyanide (hcnABC, anr) or global regulation of secondary metabolism (gacA, gacS, rsmZ). The 10 housekeeping loci rrs, dsbA, gyrB, rpoD, fdxA, recA, rpoB, rpsL, rpsG, and fusA served as controls. Each strain was readily distinguished from the others when considering allelic combinations for these 14 biocontrol-relevant loci. Topology comparisons based on Shimodaira-Hasegawa tests showed extensive incongruence when comparing single-locus phylogenetic trees with one another, but less when comparing (after sequence concatenation) trees inferred for genes involved in 2,4-diacetylphloroglucinol synthesis, hydrogen cyanide synthesis, or secondary metabolism global regulation with trees for housekeeping genes. The 14 loci displayed linkage disequilibrium, as housekeeping loci did, and all 12 protein-coding loci were subjected to purifying selection except for one positively-selected site in HcnA. Overall, the evolutionary history of Pseudomonas genes involved in synthesis of secondary antimicrobial metabolites important for biocontrol functions is in fact similar to that of housekeeping genes, and results suggest that they are ancestral in pseudomonads producing hydrogen cyanide and 2,4-diacetylphloroglucinol. PMID:22426436

Frapolli, Michele; Pothier, Joël F; Défago, Genevičve; Moënne-Loccoz, Yvan

2012-06-01

325

[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

326

Neonatal nosocomial sepsis in a level-III NICU: evaluation of the causative agents and antimicrobial susceptibilities  

Microsoft Academic Search

Despite advances in supportive care and use of antibiotics, sepsis preserves its importance due to its high mortality and morbidity for neonates. Identifying the causative agents and antibiotic resistance yearly in a neonatal intensive care unit (NICU) helps the physician to choose the most appropriate empirical therapy. In this study we aimed to evaluate positive blood cultures and antibiotic susceptibilities

Mehmet Yalaz; Hasan Çetin; Mete Akisu; Alper Tunger; Nilgün Kültürsay

2006-01-01

327

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

328

Isolation, Diversity, and Antimicrobial Activity of Rare Actinobacteria from Medicinal Plants of Tropical Rain Forests in Xishuangbanna, China? †  

PubMed Central

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

2009-01-01

329

Susceptibility of staphylococci and enterococci to antimicrobial agents at different ward levels in four north European countries.  

PubMed

A multicentre susceptibility study was performed on staphylococci and enterococci isolated from patients at 3 different ward levels: primary care centres (PCCs), general hospital wards (GHWs) and intensive care units (ICUs), in Denmark, Finland, Norway and Sweden. There was a markedly higher incidence of resistance among CoNS in ICUs compared to GHWs and PCCs. Resistance rates were low among S. aureus isolates and no differences were found between the ward levels. Oxacillin resistance was found among 1.6% of S. aureus and 47% of CoNS isolates. 14% of CoNS and 0.9% of S. aureus isolates were glycopeptide intermediate. The prevalence of E. faecium isolates in this study differed significantly between the ward levels with the lowest prevalence found at PCCs. High level gentamicin resistant (HLGR) enterococci occurred in 11-25% of E. faecium and 6-20% of E. faecalis isolates. The HLGR rate was significantly higher among E. faecalis from hospitalized patients (GHWs and ICUs) compared to patients at PCCs. For enterococcal isolates, no other significant differences in antimicrobial resistance were found between the ward levels. All enterococci were teicoplanin susceptible, but decreased susceptibility to vancomycin was found among 2.0% and 0.6% of the E. faecium and E. faecalis isolates, respectively. PMID:17852944

Claesson, Carina; Hällgren, Anita; Nilsson, Maud; Svensson, Erik; Hanberger, Hĺkan; Nilsson, Lennart E

2007-01-01

330

The use of a multi-agent paradigm in electrical plant condition monitoring  

Microsoft Academic Search

Electrical utilities need to operate their equipment closer to their design limits and require to extend their operating life through automatic condition monitoring systems. This paper introduces a multi agent paradigm for data interpretation in electrical plant monitoring. Data interpretation is of significant importance to infer the state of the equipment by converting the condition monitoring data into appropriate information.

E. E. Mangina; S. D. J. McArthur; J. R. McDonald

2001-01-01

331

Antimicrobial activity of plants used in traditional medicine of San Juan province, Argentine.  

PubMed

Eighteen extracts from Acaena magellanica, Baccharis grisebachii, Ephedra breana, Oxalis erythrorhiza, Pachylaena atriplicifolia and Satureja parvifolia were assessed for antimicrobial activity against bacteria and fungi with the agar dilution method. The hexane (H) and dichloromethane (DCM) extracts of B. grisebachii and O. erythrorhiza showed the broadest spectrum of action against fungi, inhibiting all of the tested dermatophytes with MICs ranging from < or =25 to < or =1000 microg/ml. Trichophyton rubrum was the most susceptible species and Cryptococcus neoformans was inhibited only by the DCM extract of B. grisebachii with MIC of 600 microg/ml. Regarding the antibacterial activity, H and DCM extracts of B. grisebachii as well as the DCM of O. erythrorhiza, were active on methicillin-resistant and methicillin-sensitive Staphylococcus aureus with MIC from < or =125 to < or =500 microg/ml. The DCM extract of B. grisebacchii was more active against methicillin-resistant than methicillin-sensitive strains. PMID:11585697

Feresin, G E; Tapia, A; López, S N; Zacchino, S A

2001-11-01

332

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

333

Antimicrobial Peptides: Versatile Biological Properties  

PubMed Central

Antimicrobial peptides are diverse group of biologically active molecules with multidimensional properties. In recent past, a wide variety of AMPs with diverse structures have been reported from different sources such as plants, animals, mammals, and microorganisms. The presence of unusual amino acids and structural motifs in AMPs confers unique structural properties to the peptide that attribute for their specific mode of action. The ability of these active AMPs to act as multifunctional effector molecules such as signalling molecule, immune modulators, mitogen, antitumor, and contraceptive agent makes it an interesting candidate to study every aspect of their structural and biological properties for prophylactic and therapeutic applications. In addition, easy cloning and recombinant expression of AMPs in heterologous plant host systems provided a pipeline for production of disease resistant transgenic plants. Besides these properties, AMPs were also used as drug delivery vectors to deliver cell impermeable drugs to cell interior. The present review focuses on the diversity and broad spectrum antimicrobial activity of AMPs along with its multidimensional properties that could be exploited for the application of these bioactive peptides as a potential and promising drug candidate in pharmaceutical industries. PMID:23935642

Pushpanathan, Muthuirulan; Rajendhran, Jeyaprakash

2013-01-01

334

Use of Antimicrobials during Pregnancy  

PubMed Central

The use of any drug during pregnancy is complicated by concerns of adverse effects, not only on the pregnant woman, but also on the fetus. This paper provides an overview of the use of antimicrobials in pregnancy, based on current knowledge of fetal development and on available documented experience. The author also discusses the use of specific antimicrobial agents during pregnancy. PMID:21263935

Nicolle, L.E.

1987-01-01

335

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

336

Evaluation of treatment and prophylaxis with nitrofurans and comparison with alternative antimicrobial agents in experimental Salmonella enterica Serovar enteritidis infection in chicks.  

PubMed

The ability of the nitrofuran antimicrobial agents furazolidone and furaltadone to prevent, reduce or eliminate Salmonella enterica serovar enteritidis PT4 infection in artificially challenged day-old chicks was evaluated. Treating the birds with the nitrofurans failed to eliminate established infections with either furazolidone-resistant (FzR) or furazolidone-sensitive (FzS) strains. Simultaneous administration of the nitrofurans to day-old chicks challenged with FzS failed to prevent infection but reduced colonization significantly (p<0.05) compared to unmedicated controls. No reduction of colonization occurred with FzR. Challenging birds with FzS and simultaneous dosing with nitrofurans for 1 week, followed by a second week of continued treatment, resulted in an increase in the level of colonization in the second week rather than a decrease. Dosing with the nitrofurans (200 ppm) for 1 week prior to challenge with FzS and continued medication for a further week prevented colonization of the caecum, liver and spleen. However, cessation of dosing at the time of challenge with salmonella resulted in colonization. Chloramphenicol and tetracycline at concentrations of 200 ppm were both independently capable of preventing colonization by salmonella. Sulphadiazine initially reduced colonization but failed to eliminate the infection. Only when furazolidone was combined with chloramphenicol or when sulphadiazine was combined with trimethoprim, and the combined drugs were administered concurrently with the challenge, was colonization prevented. PMID:12872826

Chadfield, M S; Hinton, M H

2003-05-01

337

Determining the ecological impacts of organic contaminants in biosolids using a high-throughput colorimetric denitrification assay: a case study with antimicrobial agents.  

PubMed

Land application accounts for ? 50% of wastewater solid disposal in the United States. Still, little is known regarding the ecological impacts of nonregulated contaminants found in biosolids. Because of the myriad of contaminants, there is a need for a rapid, high-throughput method to evaluate their ecotoxicity. Herein, we developed a novel assay that measures denitrification inhibition in a model denitrifier, Paracoccus denitrificans Pd1222. Two common (triclosan and triclocarban) and four emerging (2,4,5 trichlorophenol, 2-benzyl-4-chlorophenol, 2-chloro-4-phenylphenol, and bis(5-chloro-2-hydroxyphenyl)methane) antimicrobial agents found in biosolids were analyzed. Overall, the assay was reproducible and measured impacts on denitrification over 3 orders of magnitude exposure. The lowest observable adverse effect concentrations (LOAECs) were 1.04 ?M for triclosan, 3.17 ?M for triclocarban, 0.372 ?M for bis-(5-chloro-2-hydroxyphenyl)methane, 4.89 ?M for 2-chloro-4-phenyl phenol, 45.7 ?M for 2-benzyl-4-chorophenol, and 50.6 ?M for 2,4,5-trichlorophenol. Compared with gene expression and cell viability based methods, the denitrification assay was more sensitive and resulted in lower LOAECs. The increased sensitivity, low cost, and high-throughput adaptability make this method an attractive alternative for meeting the initial testing regulatory framework for the Federal Insecticide, Fungicide, and Rodenticide Act, and recommended for the Toxic Substances Control Act, in determining the ecotoxicity of biosolids-derived emerging contaminants. PMID:24410196

Holzem, R M; Stapleton, H M; Gunsch, C K

2014-02-01

338

Screening of hundred Rwandese medicinal plants for antimicrobial and antiviral properties  

Microsoft Academic Search

A series of 100 Rwandese medicinal plants (267 plant extracts), used by traditional healers to treat infections, were screened for antibacterial, antifungal and antiviral properties. The results of the testing showed that 45% were active against Staphylococcus aureus, 2% against Escherichia coli, 16% against Pseudomonas aeruginosa, 7% against Candida albicans, 80% against Microsporum canis and 60% against Trichophyton mentagrophytes. Not

A. J. Vlietinck; L. Van Hoof; J. Totté; A. Lasure; D. Vanden Berghe; P. C. Rwangabo; J. Mvukiyumwami

1995-01-01

339

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

340

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

PubMed

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

341

Expression of an Engineered Heterologous Antimicrobial Peptide in Potato Alters Plant Development and Mitigates Normal Abiotic and Biotic Responses  

PubMed Central

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

342

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

343

Stacking of antimicrobial genes in potato transgenic plants confers increased resistance to bacterial and fungal pathogens.  

PubMed

Solanum tuberosum plants were transformed with three genetic constructions expressing the Nicotiana tabacum AP24 osmotine, Phyllomedusa sauvagii dermaseptin and Gallus gallus lysozyme, and with a double-transgene construction expressing the AP24 and lysozyme sequences. Re-transformation of dermaseptin-transformed plants with the AP24/lysozyme construction allowed selection of plants simultaneously expressing the three transgenes. Potato lines expressing individual transgenes or double- and triple-transgene combinations were assayed for resistance to Erwinia carotovora using whole-plant and tuber infection assays. Resistance levels for both infection tests compared consistently for most potato lines and allowed selection of highly resistant phenotypes. Higher resistance levels were found in lines carrying the dermaseptin and lysozyme sequences, indicating that theses proteins are the major contributors to antibacterial activity. Similar results were obtained in tuber infection tests conducted with Streptomyces scabies. Plant lines showing the higher resistance to bacterial infections were challenged with Phytophthora infestans, Rhizoctonia solani and Fusarium solani. Considerable levels of resistance to each of these pathogens were evidenced employing semi-quantitative tests based in detached-leaf inoculation, fungal growth inhibition and in vitro plant inoculation. On the basis of these results, we propose that stacking of these transgenes is a promising approach to achieve resistance to both bacterial and fungal pathogens. PMID:22115953

Rivero, Mercedes; Furman, Nicolás; Mencacci, Nicolás; Picca, Pablo; Toum, Laila; Lentz, Ezequiel; Bravo-Almonacid, Fernando; Mentaberry, Alejandro

2012-01-20

344

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

345

Activities of gemifloxacin (SB 265805, LB20304) compared to those of other oral antimicrobial agents against unusual anaerobes.  

PubMed

The activities of gemifloxacin (SB 265805, LB20304) and comparator agents were determined by an agar dilution method against 419 clinical strains of less-commonly identified species of anaerobes. Gemifloxacin was generally more active than trovafloxacin against gram-positive strains by one to two dilutions. Peptostreptococci (Peptostreptococcus asaccharolyticus, Peptostreptococcus magnus, Peptostreptococcus micros, and Peptostreptococcus prevotii) and Porphyromonas spp. (Porphyromonas asaccharolytica, Porphyromonas canoris, Porphyromonas gingivalis, and Porphyromonas macacae) were all susceptible to /=4 microgram/ml). PMID:10543754

Goldstein, E J; Citron, D M; Vreni Merriam, C; Tyrrell, K; Warren, Y

1999-11-01

346

Biological screening of some Turkish medicinal plant extracts for antimicrobial and toxicity activities.  

PubMed

Screening of antibacterial activity and toxicity of 22 aqueous plant extracts from 17 Turkish plants was conducted. Antibacterial activity was performed with six bacteria including Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Streptococcus pyogenes, Staphylococcus aureus and Staphylococcus epidermidis. Extracts of Tussilago farfara leaves, Helichyrsum plicatum flowers, Solanum dulcamara aerial parts and Urtica dioica leaves gave the best inhibitory activity against S. pyogenes, S. aureus and S. epidermidis. Of the 22 plant extracts, 20 extracts displayed toxicity (LC50 was <1000 mg L(-1)) in the brine shrimp bioassay. For radish seed bioassay, two different determinations (root length and seed germination) were performed with a comparison between two concentrations (50,000 mg L(-1) and 10,000 mg L(-1)). At low concentration (10,000 mg L(-1)), S. dulcamara aerial parts and Primula vulgaris leaf extracts were observed to inhibit the root length more than the other plant extracts. Also, the most inhibitive plant extract for seed germination was obtained with S. dulcamara aerial parts. PMID:18075897

Turker, A U; Usta, C

2008-01-20

347

Activity of endodontic antibacterial agents against selected anaerobic bacteria  

Microsoft Academic Search

The antimicrobial activity of substances used as antibacterial agents (solutions of 10% calcium hydroxide, camphorated paramono- chlorophenol - PMCC, 2% chlorhexidine digluconate and 10% castor oil plant detergent) on anaerobic bacteria (Fusobacterium nucleatum ATCC 25586, Prevotella nigrescens ATCC 33563, Clostridium perfringens ATCC 13124 and Bacteroides fragilis ATCC 25285), using a broth dilution technique, was evaluated in vitro. For determination of

Cláudio Maniglia Ferreira; Odila Pereira da Silva; Sérgio Aparecido Torres; Flaviana Bombarda de Andrade Ferreira; Norberti Bernardinelli

2002-01-01

348

The anti-microbial efficacy of plant essential oil combinations and interactions with food ingredients  

Microsoft Academic Search

The objective of this study was to evaluate the efficacy of plant essential oils (EOs) in combination and to investigate the effect of food ingredients on their efficacy. The EOs assessed in combination included basil, lemon balm, marjoram, oregano, rosemary, sage and thyme. Combinations of EOs were initially screened against Bacillus cereus, Escherichia coli, Listeria monocytogenes and Pseudomonas aeruginosa using

Jorge Gutierrez; Catherine Barry-Ryan; Paula Bourke

2008-01-01

349

The antimicrobial efficacy of plant essential oil combinations and interactions with food ingredients  

Microsoft Academic Search

The objective of this study was to evaluate the efficacy of plant essential oils (EOs) in combination and to investigate the effect of food ingredients on their efficacy. The EOs assessed in combination included basil, lemon balm, marjoram, oregano, rosemary, sage and thyme. Combinations of EOs were initially screened against Bacillus cereus, Escherichia coli, Listeria monocytogenes and Pseudomonas aeruginosa using

J. Gutierrez; C. Barry-Ryan; P. Bourke

2008-01-01

350

Antimicrobial Screening of the Essential Oil of Some Herbal Plants from Western Nigeria  

Microsoft Academic Search

2 Abstract: The essential oil from ten herbal plants namely Momordica charantia, Ocimum gratissimum, Senna alata, Phyllantus reticulata, Dissotis rotundifolia, Gossypium hirsutum, Boerhaavia diffusa, Sida acuta, Paullinia pinnata and Senna podocarpa were extracted using hydro-distillation process. The oils were characterised based on their colour and UV spectroscopy. Five out of the ten oils were screened against Klebsiella pneumonia, Bacillus megaterium,

I. A. Ajayi; S. G. Jonathan; A. Adewuyi; R. A. Oderinde

351

Effect of quinupristin/dalfopristin on 3T3 and Eahy926 cells in vitro in comparison to other antimicrobial agents with the potential to induce infusion phlebitis.  

PubMed

Infusion phlebitis is a common clinical problem that is observed with some antimicrobial agents, when being administered intravenously. In this study, cultured murine fibroblasts and immortalised human endothelial cells were exposed to three antibiotics at clinically relevant concentrations to assess their toxic potential in two established cytotoxicity assays. BALB/c 3T3 fibroblasts and Eahy926 endothelial cells were exposed to quinupristin/dalfopristin (QD), erythromycin and levofloxacin at increasing concentrations. For assessment of cytotoxicity the cells were incubated with neutral red (NR) or stained with crystal violet (CV). Measurements were done by photometry. At the concentration range tested QD and erythromycin showed a concentration-dependent cytotoxic effect in both cell cultures. In 3T3 cells the half-maximal effect concentration (EC50) was 20 mg/l for QD and 340 mg/l for erythromycin in the NR uptake test and 12 and 200 mg/l, respectively, in the CV assay. In Eahy926 cells the EC50 was 50 mg/l for QD and 880 mg/l for erythromycin in the NR uptake test and 40 and 750 mg/l, respectively, in the CV assay. No EC50 could be established in both cell types for levofloxacin. Eahy926 cells were less sensitive to cytotoxic stimuli than 3T3 fibroblasts. Cytotoxic effects in both cell cultures occurred in the following order: QD > erythromycin > levofloxacin. This ranking correlates well with the frequency of local adverse effects observed with the infusion of these antibiotics in patients. Thus, these in vitro assays may serve as an estimate for the prediction of local tolerability of antibiotics when administered parenterally. PMID:17119926

Kruse, Matthias; Kilic, Bülent; Flick, Burkhard; Stahlmann, Ralf

2007-06-01

352

Evaluation of antimicrobial agents using an experimental pulmonary superinfection model with Aspergillus fumigatus and Pseudomonas aeruginosain leukopenic mice.  

PubMed

The therapeutic efficacy of amphotericin B (AmB), imipenem/cilastatin (IPM/CS), pazufloxacin (PZFX) mesilate, and combinations of these, was evaluated using an experimental pulmonary superinfection model in mice caused by Pseudomonas aeruginosa and Aspergillus fumigatus. The superinfected mice died within 3 days. Although the viable cell count of P. aeruginosa increased markedly from 10(3) to 10(8) CFU/lung on day 2 after infection, that of A. fumigatus decreased from 10(3) to 10(2) CFU/lung on that day, showing that P. aeruginosa facilitated the mortality in the superinfection. Extensive necrosis in the lung parenchyma and moderate hyphae proliferation of A. fumigatus were observed on day 2 after infection. Mice treated with PZFX mesilate (50 mg/kg per day) and the combination of PZFX mesilate (50 mg/kg per day) - AmB (2.5 mg/kg per day) showed prolonged survival in comparison to untreated control mice ( P < 0.05). In the PZFX mesilate-treated group, no significant necrosis was observed, but necrosis due to the hyphae proliferation of A. fumigatus was still observed in the lung parenchyma on day 6 after infection. However, neither significant necrosis nor hyphae proliferation of A. fumigatus was observed in mice treated with the combination of PZFX mesilate - AmB. On the other hand, the survival rates of mice treated with AmB (2.5 mg/kg per day), IPM/CS (50 mg/kg per day), and the IPM/CS-AmB combination were all less than 10%. The viable cell count of P. aeruginosa decreased in PZFX mesilate-alone group and in the combination of PZFX mesilate - AmB group, but no significant decrease in this count was observed in the IPM/CS and combination of IPM/CS-AmB group. The viable count of A. fumigatus was increased in the IPM/CS, PZFX mesilate-alone, and combination of IPM/CS-AmB groups, but the count was suppressed in the AmB-alone and the combination of PZFX mesilate - AmB group. In conclusion, this superinfection model would be useful to evaluate the therapeutic potential of combinations of antibacterial and antifungal agents, and the scheduling of drug administration in terminal infections caused by P. aeruginosa and A. fumigatus. PMID:12825113

Mitsuyama, Junichi; Kizawa, Kazuo; Minami, Shinzaburo; Watanabe, Yasuo; Yamaguchi, Keizo

2003-06-01

353

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

354

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

355

Biosynthesis of silver nanoparticles using latex from few Euphorbian plants and their antimicrobial potential.  

PubMed

The synthesis of well-dispersed and ultrafine metal nanoparticles has great interest due to their distinctive physicochemical properties and biomedical applications. This study is the first report of one-step solvent-free synthesis of AgNPs using Euphorbiaceae plant latex. Among evaluated eight latex-producing plants, four (Jatropha curcas, Jatropha gossypifolia, Pedilanthus tithymaloides, and Euphorbia milii) showed high potential to produce physicochemically distinct, small-sized and bactericidal AgNPs. Phytochemical screening showed presence of rich amount of biochemicals in these plants. J. gossypifolia showed uniformly dispersed comparatively small-sized AgNPs. Dose-dependent growth inhibition of bacterial pathogens Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermis, and Micrococcus luteus was observed for J. gossypifolia latex-synthesized AgNPs with minimum inhibitory concentration values 30, 40, 70, 60, and 60 ppm, respectively, after 24 h. Possible mode of action of AgNPs against pathogens was confirmed by analyzing enzymes and cell leakage. PMID:22592777

Patil, Satish V; Borase, Hemant P; Patil, Chandrashekhar D; Salunke, Bipinchandra K

2012-06-01

356

Antimicrobial Pesticides  

NSDL National Science Digital Library

This newly launched site from the US Environmental Protection Agency (EPA) offers a variety of resources describing how the EPA regulates antimicrobial pesticides. Antimicrobial pesticides are used in a huge variety of household and commercial products to "disinfect, sanitize, reduce, or mitigate growth or development of microbiological organisms" and to "protect inanimate objects (for example floors and walls), industrial processes or systems, surfaces, water, or other chemical substances from contamination, fouling, or deterioration caused by bacteria, viruses, fungi, protozoa, algae, or slime." Intended mainly for a regulatory audience, the site includes Antimicrobials Science Policy Documents, Antimicrobials Registration Policy Documents, Label Review Manual, Chemical/ Registration Number Indexes, and Antimicrobial PR notices.

357

Antimicrobial activity of enterocins from Enterococcus faecalis SL5 against Propionibacterium acnes , the causative agent in acne vulgaris, and its therapeutic effect  

Microsoft Academic Search

A lactic acid bacterial strain was isolated from human fecal specimen and identified as Enterococcus faecalis SL-5. The isolated strain showed antimicrobial activity against Gram-positive pathogens assayed, especially the highest activity\\u000a against Propionibacterium acnes. The antimicrobial substance was purified and verified as a bacteriocin (named ESL5) of E. faecalis SL-5 by activity-staining using P. acnes as an indicator. N-terminal sequence

Bong Seon Kang; Jae-Gu Seo; Gwa-Su Lee; Jung-Hwa Kim; Sei Yeon Kim; Ye Won Han; Hoon Kang; Hyung Ok Kim; Ji Hwan Rhee; Myung-Jun Chung; Young Min Park

2009-01-01

358

Antimicrobial therapy for acute cholecystitis: Tokyo Guidelines.  

PubMed

Acute cholecystitis consists of various morbid conditions, ranging from mild cases that are relieved by the oral administration of antimicrobial drugs or that resolve even without antimicrobials to severe cases complicated by biliary peritonitis. Microbial cultures should be performed by collecting bile at all available opportunities to identify both aerobic and anaerobic organisms. Empirically selected antimicrobials should be administered. Antimicrobial activity against potential causative organisms, the severity of the cholecystitis, the patient's past history of antimicrobial therapy, and local susceptibility patterns (antibiogram) must be taken into consideration in the choice of antimicrobial drugs. In mild cases which closely mimic biliary colic, the administration of nonsteroidal anti-inflammatory drugs (NSAIDs) is recommended to prevent the progression of inflammation (recommendation grade A). When causative organisms are identified, the antimicrobial drug should be changed for a narrower-spectrum antimicrobial agent on the basis of the species and their susceptibility testing results. PMID:17252301

Yoshida, Masahiro; Takada, Tadahiro; Kawarada, Yoshifumi; Tanaka, Atsushi; Nimura, Yuji; Gomi, Harumi; Hirota, Masahiko; Miura, Fumihiko; Wada, Keita; Mayumi, Toshihiko; Solomkin, Joseph S; Strasberg, Steven; Pitt, Henry A; Belghiti, Jacques; de Santibanes, Eduardo; Fan, Sheung-Tat; Chen, Miin-Fu; Belli, Giulio; Hilvano, Serafin C; Kim, Sun-Whe; Ker, Chen-Guo

2007-01-01

359

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 Ĺ) 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-Ramirez, Armando; Aguilera, Renato J.; Contel, Maria

2011-01-01

360

Plant sterols/stanols as cholesterol lowering agents: A meta-analysis of randomized controlled trials  

PubMed Central

Background Consumption of plant sterols has been reported to reduce low density lipoprotein (LDL) cholesterol concentrations by 5–15%. Factors that affect plant sterol efficacy are still to be determined. Objectives To more precisely quantify the effect of plant sterol enriched products on LDL cholesterol concentrations than what is reported previously, and to identify and quantify the effects of subjects’ characteristics, food carrier, frequency and time of intake on efficacy of plant sterols as cholesterol lowering agents. Design Fifty-nine eligible randomized clinical trials published from 1992 to 2006 were identified from five databases. Weighted mean effect sizes were calculated for net differences in LDL levels using a random effect model. Results Plant sterol containing products decreased LDL levels by 0.31 mmol/L (95% CI, –0.35 to –0.27, P=?plant sterols were incorporated into fat spreads, mayonnaise and salad dressing, milk and yoghurt comparing with other food products such as croissants and muffins, orange juice, non-fat beverages, cereal bars, and chocolate. Plant sterols consumed as a single morning dose did not have a significant effect on LDL cholesterol levels. Conclusion Plant sterol containing products reduced LDL concentrations but the reduction was related to individuals’ baseline LDL levels, food carrier, and frequency and time of intake. PMID:19109655

AbuMweis, Suhad S.; Barake, Roula; Jones, Peter J.H.

2008-01-01

361

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

362

The Potential of Antimicrobial Peptides as Biocides  

PubMed Central

Antimicrobial peptides constitute a diverse class of naturally occurring antimicrobial molecules which have activity against a wide range of pathogenic microorganisms. Antimicrobial peptides are exciting leads in the development of novel biocidal agents at a time when classical antibiotics are under intense pressure from emerging resistance, and the global industry in antibiotic research and development stagnates. This review will examine the potential of antimicrobial peptides, both natural and synthetic, as novel biocidal agents in the battle against multi-drug resistant pathogen infections. PMID:22072905

Laverty, Garry; Gorman, Sean P.; Gilmore, Brendan F.

2011-01-01

363

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.; Picanco, Marcelo C.; Semeao, Altair A.; Barreto, Robert W.; Rosado, Jander F.; Martins, Julio C.

2012-01-01

364

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

365

Isolation and characterization of soil Streptomyces species as potential biological control agents against fungal plant pathogens.  

PubMed

The use of antagonist microorganisms against fungal plant pathogens is an attractive and ecologically alternative to the use of chemical pesticides. Streptomyces are beneficial soil bacteria and potential candidates for biocontrol agents. This study reports the isolation, characterization and antagonist activity of soil streptomycetes from the Los Petenes Biosphere Reserve, a Natural protected area in Campeche, Mexico. The results showed morphological, physiological and biochemical characterization of six actinomycetes and their inhibitory activity against Curvularia sp., Aspergillus niger, Helminthosporium sp. and Fusarium sp. One isolate, identified as Streptomyces sp. CACIS-1.16CA showed the potential to inhibit additional pathogens as Alternaria sp., Phytophthora capsici, Colletotrichum sp. and Rhizoctonia sp. with percentages ranging from 47 to 90 %. This study identified a streptomycete strain with a broad antagonist activity that could be used for biocontrol of plant pathogenic fungi. PMID:24310522

Evangelista-Martínez, Zahaed

2014-05-01

366

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

367

In Vitro Antimicrobial Potential of the Lichen Parmotrema sp. Extracts against Various Pathogens  

PubMed Central

Objective(s): The ongoing increasing antibiotic resistance is one of the biggest challenges faced by global public health. The perennial need for new antimicrobials against a background of increasing antibiotic resistance in pathogenic and opportunistic microorganisms obliges the scientific community to constantly develop new drugs and antimicrobial agents. Lichens are known prolific sources of natural antimicrobial drugs and biologically active natural products. This study was aimed to explore in vitro antimicrobial activity of lichen Parmotrema sp. Material and Methods: The methanol and aqueous extracts of lichen Parmotrema sp. was extracted using Soxhlet extractor. Antibiotic assessment of methanol and aqueous extracts was done against eight bacterial (Escherichia coli, Staphylococcus aureus, Proteus mirabilis, Salmonella sp., Shigella sp., Enterococci faecalis, Pseudomonas aeruginosa, Klebsiella pneumoniae,) clinical pathogens and five plant pathogenic fungal strains (Aspergillus terreus strain JAS1, Scedosporium sp. JAS1, Ganoderma sp. JAS4, Candida tropicalis and Fusarium sp.) by Kirby-Bauer method. Results: The methanol lichen Parmotrema sp. extract inhibited all the test organisms. The highest antibacterial activity was found against Pseudomonas aeruginosa and Staphylococcus aureus. The weakest activity was manifested in Salmonella sp. and Scedosporium sp. JAS1. Strong antifungal effect was found against Ganoderma sp. JAS4 and Fusarium sp. The aqueous lichen Parmotrema sp. extract revealed neither antibacterial nor antifungal activity. Conclusion: The present study shows that tested lichen Parmotrema sp. extracts demonstrated a strong antimicrobial effect. That suggests the active components from methanol extracts of the investigated lichen Parmotrema sp. can be used as natural antimicrobial agent against pathogens. PMID:23997920

Chauhan, Ritika; Abraham, Jayanthi

2013-01-01

368

Probing Protein Sequences as Sources for Encrypted Antimicrobial Peptides  

PubMed Central

Starting from the premise that a wealth of potentially biologically active peptides may lurk within proteins, we describe here a methodology to identify putative antimicrobial peptides encrypted in protein sequences. Candidate peptides were identified using a new screening procedure based on physicochemical criteria to reveal matching peptides within protein databases. Fifteen such peptides, along with a range of natural antimicrobial peptides, were examined using DSC and CD to characterize their interaction with phospholipid membranes. Principal component analysis of DSC data shows that the investigated peptides group according to their effects on the main phase transition of phospholipid vesicles, and that these effects correlate both to antimicrobial activity and to the changes in peptide secondary structure. Consequently, we have been able to identify novel antimicrobial peptides from larger proteins not hitherto associated with such activity, mimicking endogenous and/or exogenous microorganism enzymatic processing of parent proteins to smaller bioactive molecules. A biotechnological application for this methodology is explored. Soybean (Glycine max) plants, transformed to include a putative antimicrobial protein fragment encoded in its own genome were tested for tolerance against Phakopsora pachyrhizi, the causative agent of the Asian soybean rust. This procedure may represent an inventive alternative to the transgenic technology, since the genetic material to be used belongs to the host organism and not to exogenous sources. PMID:23029273

Brand, Guilherme D.; Magalhaes, Mariana T. Q.; Tinoco, Maria L. P.; Aragao, Francisco J. L.; Nicoli, Jacques; Kelly, Sharon M.; Cooper, Alan; Bloch, Carlos

2012-01-01

369

Probing protein sequences as sources for encrypted antimicrobial peptides.  

PubMed

Starting from the premise that a wealth of potentially biologically active peptides may lurk within proteins, we describe here a methodology to identify putative antimicrobial peptides encrypted in protein sequences. Candidate peptides were identified using a new screening procedure based on physicochemical criteria to reveal matching peptides within protein databases. Fifteen such peptides, along with a range of natural antimicrobial peptides, were examined using DSC and CD to characterize their interaction with phospholipid membranes. Principal component analysis of DSC data shows that the investigated peptides group according to their effects on the main phase transition of phospholipid vesicles, and that these effects correlate both to antimicrobial activity and to the changes in peptide secondary structure. Consequently, we have been able to identify novel antimicrobial peptides from larger proteins not hitherto associated with such activity, mimicking endogenous and/or exogenous microorganism enzymatic processing of parent proteins to smaller bioactive molecules. A biotechnological application for this methodology is explored. Soybean (Glycine max) plants, transformed to include a putative antimicrobial protein fragment encoded in its own genome were tested for tolerance against Phakopsora pachyrhizi, the causative agent of the Asian soybean rust. This procedure may represent an inventive alternative to the transgenic technology, since the genetic material to be used belongs to the host organism and not to exogenous sources. PMID:23029273

Brand, Guilherme D; Magalhăes, Mariana T Q; Tinoco, Maria L P; Aragăo, Francisco J L; Nicoli, Jacques; Kelly, Sharon M; Cooper, Alan; Bloch, Carlos

2012-01-01

370

Towards identifying novel anti-Eimeria agents: trace elements, vitamins, and plant-based natural products.  

PubMed

Eimeriosis, a widespread infectious disease of livestock, is caused by coccidian protozoans of the genus Eimeria. These obligate intracellular parasites strike the digestive tract of their hosts and give rise to enormous economic losses, particularly in poultry, ruminants including cattle, and rabbit farming. Vaccination, though a rational prophylactic measure, has not yet been as successful as initially thought. Numerous broad-spectrum anti-coccidial drugs are currently in use for treatment and prophylactic control of eimeriosis. However, increasing concerns about parasite resistance, consumer health, and environmental safety of the commercial drugs warrant efforts to search for novel agents with anti-Eimeria activity. This review summarizes current approaches to prevent and treat eimeriosis such as vaccination and commercial drugs, as well as recent attempts to use dietary antioxidants as novel anti-Eimeria agents. In particular, the trace elements selenium and zinc, the vitamins A and E, and natural products extracted from garlic, barberry, pomegranate, sweet wormwood, and other plants are discussed. Several of these novel anti-Eimeria agents exhibit a protective role against oxidative stress that occurs not only in the intestine of Eimeria-infected animals, but also in their non-parasitized tissues, in particular, in the first-pass organ liver. Currently, it appears to be promising to identify safe combinations of low-cost natural products with high anti-Eimeria efficacy for a potential use as feed supplementation in animal farming. PMID:25185667

Wunderlich, Frank; Al-Quraishy, Saleh; Steinbrenner, Holger; Sies, Helmut; Dkhil, Mohamed A

2014-10-01

371

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

372

Synthesis and biological evaluation of (E)-1-(substituted)-3-phenylprop-2-en-1-ones bearing rhodanines as potent anti-microbial agents.  

PubMed

Abstract Herein, we report the design, syntheses and in vitro anti-microbial activity of two series of rhodanines with chalcone moiety. Anti-microbial tests showed that some of the synthesized compounds exhibited good inhibition (MIC?=?1-8?µg/mL) against multi-drug-resistant Gram-positive organisms, including methicillin resistant and quinolone-resistant Staphylococcus aureus, in which the compound 4g was found to be the most potent with minimum inhibitory concentration (MIC) value of 1?µg/mL against two methicillin-resistant S. aureus. PMID:24102526

Song, Ming-Xia; Deng, Xian-Qing; Li, Ya-Ru; Zheng, Chang-Ji; Hong, Lan; Piao, Hu-Ri

2014-10-01

373

ANTIMICROBIAL EFFECTS ON STARCH-BASED FILMS INCORPORATED WITH LYSOZYMES  

Microsoft Academic Search

An antimicrobial (AM) Active Packaging can be made by incorporating and immobilizing suitable AM agents into food packages and applying a bio switch concept. A starch-based film was prepared and incorporated with antimicrobial agents, i.e. lysozyme and EDTA as chelating agent. This film was then inoculated with the bacteria Escherichia coli and Bacillus subtilis to carry out the microbial contamination

Nozieana Khairuddin; Ida Idayu Muhamad

374

Inactivation of Listeria monocytogenes on frankfurters by plant-derived antimicrobials alone or in combination with hydrogen peroxide.  

PubMed

Listeria monocytogenes is a significant foodborne pathogen associated with outbreaks involving contaminated ready-to-eat (RTE) products, including frankfurters. The USDA-FSIS has established a zero tolerance policy for L. monocytogenes in RTE products, thereby warranting effective post-processing interventions to control the pathogen on these foods. In the present study, the antilisterial activity of GRAS (generally recognized as safe)-status plant-derived antimicrobials (PDAs), namely ?-resorcylic acid (BR), carvacrol (CR), and trans-cinnamaldehyde (TC) either alone or in combination with hydrogen peroxide (HP) as post-processing dip treatments on frankfurters was investigated. Frankfurters were surface inoculated with a five-strain mixture of L. monocytogenes (~6.0 log CFU per frankfurter), followed by dip treatment at 55 °C for 60s or 65 °C for 30s in sterile deionized water, or water containing BR (1.5%), CR (0.75%), or TC (0.75%) either alone or in combination with HP (0.1%). Treated frankfurters were vacuum-packaged, and stored at 4 °C for 70 days. Representative samples were analyzed on days 0, 1, 3, 7, 14, 28, 42, 56, and 70 of refrigerated storage for enumerating surviving L. monocytogenes on frankfurters. Six frankfurters were sampled at each time point for each treatment. On day zero, all PDAs reduced L. monocytogenes counts by >2 log CFU/frankfurter at both temperatures (P<0.05), compared to controls. From days 1 to 70, L. monocytogenes counts on PDA-treated frankfurters were consistently lower (P<0.05) and after 70 days of storage, the pathogen counts were reduced to undetectable levels on frankfurters treated with PDA-HP combinations at 65 °C, and by combinations of BR and TC with HP at 55 °C. Results suggest that PDAs alone, or in combination with HP could be effectively used as post-processing dips to reduce L. monocytogenes on frankfurters, although follow-up studies on sensory and quality characteristics of PDA-treated frankfurters are necessary. PMID:23558194

Upadhyay, Abhinav; Upadhyaya, Indu; Kollanoor-Johny, Anup; Ananda Baskaran, Sangeetha; Mooyottu, Shankumar; Karumathil, Deepti; Venkitanarayanan, Kumar

2013-05-15

375

Accelerating the degradation of green plant waste with chemical decomposition agents.  

PubMed

Degradation of green plant waste is often difficult, and excess maturity times are typically required. In this study, we used lignin, cellulose and hemicellulose assays; scanning electron microscopy; infrared spectrum analysis and X-ray diffraction analysis to investigate the effects of chemical decomposition agents on the lignocellulose content of green plant waste, its structure and major functional groups and the mechanism of accelerated degradation. Our results showed that adding chemical decomposition agents to Ficus microcarpa var. pusillifolia sawdust reduced the contents of lignin by 0.53%-11.48% and the contents of cellulose by 2.86%-7.71%, and increased the contents of hemicellulose by 2.92%-33.63% after 24 h. With increasing quantities of alkaline residue and sodium lignosulphonate, the lignin content decreased. Scanning electron microscopy showed that, after F. microcarpa var. pusillifolia sawdust was treated with chemical decomposition agents, lignocellulose tube wall thickness increased significantlyIncreases of 29.41%, 3.53% and 34.71% were observed after treatment with NaOH, alkaline residue and sodium lignosulphonate, respectively. Infrared spectroscopy showed that CO and aromatic skeleton stretching absorption peaks were weakened and the C-H vibrational absorption peak from out-of-plane in positions 2 and 6 (S units) (890-900 cm(-1)) was strengthened after F. microcarpa var. pusillifolia sawdust was treated with chemical decomposition agents, indicating a reduction in lignin content. Several absorption peaks [i.e., C-H deformations (asymmetry in methyl groups, -CH(3)- and -CH(2)-) (1450-1460 cm(-1)); Aliphatic C-H stretching in methyl and phenol OH (1370-1380 cm(-1)); CO stretching (cellulose and hemicellulose) (1040-1060 cm(-1))] that indicate the presence of a chemical bond between lignin and cellulose was reduced, indicating that the chemical bond between lignin and cellulose had been partially broken. X-ray diffraction analysis showed that NaOH, alkaline residue and sodium lignosulphonate can reduce the relative crystallinity of lignocellulose in F. microcarpa var. pusillifolia by 2.64%, 13.24%, 12.44%, respectively. The C-H vibrational absorption peak from out-of-plane in positions 2 and 6 (S units) comes from the vibration of the sugar anomeric carbon. Because lignin is a phenolic, not carbohydrate polymer, the relative absorption intensity of this peak should be stronger at lower lignin contents. Compared to CK, the peak intensities increased in treatments T1, T5 and T9, indicating reduced lignin contents and increased sugar contents after CDA treatment. PMID:21763065

Kejun, Sun; Juntao, Zhang; Ying, Chen; Zongwen, Liao; Lin, Ruan; Cong, Liu

2011-10-01

376

Thai ethnomedicinal plants as resistant modifying agents for combating Acinetobacter baumannii infections  

PubMed Central

Abstracts Background Acinetobacter baumannii is well-recognized as an important nosocomial pathogen, however, due to their intrinsic resistance to several antibiotics, treatment options are limited. Synergistic effects between antibiotics and medicinal plants, particularly their active components, have intensively been studied as alternative approaches. Methods Fifty-one ethanol extracts obtained from 44 different selected medicinal plant species were tested for resistance modifying agents (RMAs) of novobiocin against A. baumannii using growth inhibition assay. Results At 250??g/ml, Holarrhena antidysenterica, Punica granatum, Quisqualis indica, Terminalia bellirica, Terminalia chebula, and Terminalia sp. that possessed low intrinsic antibacterial activity significantly enhanced the activity of novobiocin at 1??g/ml (1/8xminimum inhibitory concentration) against this pathogen. Holarrhena antidysenterica at 7.8??g/ml demonstrated remarkable resistant modifying ability against A. baumannii in combination with novobiocin. The phytochemical study revealed that constituents of this medicinal plant contain alkaloids, condensed tannins, and triterpenoids. Conclusion The use of Holarrhena antidysenterica in combination with novobiocin provides an effective alternative treatment for multidrug resistant A. baumannii infections. PMID:22536985

2012-01-01

377

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

378

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

379

Exposure to chemical agents in Swedish aluminum foundries and aluminum remelting plants--a comprehensive survey.  

PubMed

Secondary aluminum melting is mainly performed in sand, die, and static die-casting foundries and remelting plants. In seven Swedish foundries and two remelting plants, the exposure and area concentrations of total dust, metals, organic gases, and vapors were determined mainly as daily, time-weighted averages (TWAs). For most combinations of jobs and agents, the exposure levels were well below the current threshold limits suggested by the American Conference of Governmental Industrial Hygienists (ACGIH). However, high exposure levels of mineral oil mist (geometric mean [GM] = 0.6 mg/m3) were observed in the die-casting process, with a maximum of 4 mg/m3. The findings were similar for total dust (GM = 5.1 mg/m3) and crystalline quartz (GM = 0.05 mg/m3) during molding operations in the sand foundries, maximum air concentrations being 31 mg/m3 and 0.22 mg/m3, respectively. Other agents which occasionally reached high exposure levels included furfuryl alcohol (up to 23 mg/m3 during furan binder use in sand foundries), aniline (up to 2.6 mg/m3 during thermal degradation of cold-box binders), and dimethylethylamine (up to 9 mg/m3) in the cold-box process used in static die-casting and sand foundries. The average aluminum exposure levels (GM = 0.043 mg/m3) were low in all foundries, individual values not exceeding 0.94 mg/m3. The exposures to metals were below 10 percent of their threshold limits. Similarly low levels were detected of polyaromatic hydrocarbons, phenol, formaldehyde, methylenebisphenyl diisocyanate, and phenylisocyanate. In the aluminum remelting plants, a few high exposure levels of total dust (GM = 1.4 mg/m3) up to 8 mg/m3 were detected in furnace workers. Aluminum and other metals were well below 10 percent of their threshold limits, with the exception of a few high concentrations of manganese, up to 0.14 mg/m3. The between-worker variability (GSDB) in the foundries for total dust, aluminum, and oil mist were on the order of 3-4. The heterogenicity of secondary aluminum melting requires assessment of a wide variety of chemical agents. For certain exposures, technical and medical monitoring programs are still needed. PMID:11202030

Westberg, H B; Seldén, A I; Bellander, T

2001-01-01

380

Expression of a Novel Antimicrobial Peptide Penaeidin4-1 in Creeping Bentgrass (Agrostis stolonifera L.) Enhances Plant Fungal Disease Resistance  

PubMed Central

Background Turfgrass species are agriculturally and economically important perennial crops. Turfgrass species are highly susceptible to a wide range of fungal pathogens. Dollar spot and brown patch, two important diseases caused by fungal pathogens Sclerotinia homoecarpa and Rhizoctonia solani, respectively, are among the most severe turfgrass diseases. Currently, turf fungal disease control mainly relies on fungicide treatments, which raises many concerns for human health and the environment. Antimicrobial peptides found in various organisms play an important role in innate immune response. Methodology/Principal Findings The antimicrobial peptide - Penaeidin4-1 (Pen4-1) from the shrimp, Litopenaeus setiferus has been reported to possess in vitro antifungal and antibacterial activities against various economically important fungal and bacterial pathogens. In this study, we have studied the feasibility of using this novel peptide for engineering enhanced disease resistance into creeping bentgrass plants (Agrostis stolonifera L., cv. Penn A-4). Two DNA constructs were prepared containing either the coding sequence of a single peptide, Pen4-1 or the DNA sequence coding for the transit signal peptide of the secreted tobacco AP24 protein translationally fused to the Pen4-1 coding sequence. A maize ubiquitin promoter was used in both constructs to drive gene expression. Transgenic turfgrass plants containing different DNA constructs were generated by Agrobacterium-mediated transformation and analyzed for transgene insertion and expression. In replicated in vitro and in vivo experiments under controlled environments, transgenic plants exhibited significantly enhanced resistance to dollar spot and brown patch, the two major fungal diseases in turfgrass. The targeting of Pen4-1 to endoplasmic reticulum by the transit peptide of AP24 protein did not significantly impact disease resistance in transgenic plants. Conclusion/Significance Our results demonstrate the effectiveness of Pen4-1 in a perennial species against fungal pathogens and suggest a potential strategy for engineering broad-spectrum fungal disease resistance in crop species. PMID:21931807

Zhou, Man; Hu, Qian; Li, Zhigang; Li, Dayong; Chen, Chin-Fu; Luo, Hong

2011-01-01

381

Removal of magnetic resonance imaging contrast agents through advanced water treatment plants.  

PubMed

Stable gadolinium (Gd) complexes have been used as paramagnetic contrast agents for magnetic resonance imaging (MRI) for over 20 years, and have recently been identified as environmental contaminants. As the rare earth elements (REE), which include Gd, are able to be measured accurately at very low concentrations (e.g. Tb is measured at 7 fmol/kg in this study) using inductively coupled plasma mass spectrometry (ICP-MS), it is possible to determine the fate of this class of compounds during the production of purified recycled water from effluent. Coagulation and microfiltration have negligible removal, with the major removal step occurring across the reverse osmosis membrane where anthropogenic Gd (the amount of Gd attributable to MRI contrast agents) is reduced from 0.39 nmol/kg to 0.59 pmol/kg, a reduction of 99.85%. The RO concentrate has anthropogenic Gd concentrations of 2.6 nmol/kg, an increase in concentration in line with the design characteristics of the plant. The increased concentration in the RO concentrate may allow further development of anthropogenic Gd as a tracer of the fate of the RO concentrate in the environment. PMID:20150705

Lawrence, Michael G; Keller, Jurg; Poussade, Yvan

2010-01-01

382

Antimicrobial resistance of Pseudomonas aeruginosa biofilms  

Microsoft Academic Search

Resistance to antimicrobial agents is the most important feature of biofilm infections. As a result, infections caused by bacterial biofilms are persistent and very difficult to eradicate. Although several mechanisms have been postulated to explain reduced susceptibility to antimicrobials in bacterial biofilms, it is becoming evident that biofilm resistance is multifactorial. The contribution of each of the different mechanisms involved

Eliana Drenkard

2003-01-01

383

Trends in the susceptibility of commonly encountered clinically significant anaerobes and susceptibilities of blood isolates of anaerobes to 16 antimicrobial agents, including fidaxomicin and rifaximin, 2008-2012, northern Taiwan.  

PubMed

We investigated the antimicrobial resistance trends and profiles of clinical anaerobic isolates in northern Taiwan. Trends in the susceptibility of five commonly encountered clinical anaerobic isolates to seven agents from 2008 to 2012 were measured using the Cochran-Armitage trend test. The minimum inhibitory concentrations (MICs) of 16 antimicrobial agents, including fidaxomicin and rifaximin, against anaerobic blood isolates from two medical centers were determined using the agar dilution method. During the study period, susceptibility data on 11,105 isolates were evaluated. Metronidazole and chloramphenicol retained excellent activities. Around 20-30 % of isolates of Bacteroides and Prevotella species were resistant to ampicillin-sulbactam, cefmetazole, flomoxef, and clindamycin. Of the 507 tested blood isolates, the rates of resistance to commonly used agents were much higher, namely, 16.2 % for amoxicillin-clavulanate, 15.6 % for ampicillin-sulbactam, 24.7 % for cefmetazole, and 36.1 % for clindamycin. Notably, 13.5 % of B. fragilis isolates were resistant to ertapenem. Also, 15.2 % of B. uniformis, 17.2 % of other Bacteroides species, 14.3 % of Prevotella species, and 14 % of Clostridium other than C. perfringens isolates were resistant to moxifloxacin. Cefoperazone-sulbactam was active against most isolates, except for Clostridium species other than perfringens (resistance rate, 18.6 %). Fidaxomicin exerted poor activities against most anaerobes tested (MIC90 of >128 ?g/ml for B. fragilis and all isolates), except for C. perfringens (MIC90 of 0.03 ?g/ml) and Peptostreptococcus micros (MIC90 of 2 ?g/ml). However, rifaximin showed a wide range of susceptibilities against the tested anaerobes (MIC90 of 0.5 ?g/ml for B. fragilis). The emergence of resistance to ertapenem and moxifloxacin among bacteremic anaerobes highlights the need for continuous monitoring. PMID:24930042

Wang, F D; Liao, C H; Lin, Y T; Sheng, W H; Hsueh, P R

2014-11-01

384

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

E-print Network

Numerous outbreaks of foodborne illness have been attributed to non-intact beef (e.g., tenderized, marinated, and enhanced) products contaminated with Escherichia coli O157:H7. Organic acids are commonly utilized in the beef industry...

Nelson, Kayla

2013-08-28

385

Synthesis and biological evaluation of ?-triazolyl chalcones as a new type of potential antimicrobial agents and their interaction with calf thymus DNA and human serum albumin.  

PubMed

A series of ?-triazolyl chalcones were efficiently synthesized. Most of the prepared compounds showed effective antibacterial and antifungal activities. Noticeably, ?-triazolyl derivative 9a exhibited low MIC value of 4 ?g/mL against MRSA and Micrococcus luteus, which was comparable or even superior to reference drugs. The further research revealed that compound 9a could effectively intercalate into Calf Thymus DNA to form 9a-DNA complex which might block DNA replication to exert their powerful antimicrobial activities. Competitive interactions between 9a and metal ions to Human Serum Albumin (HSA) suggested the participation of Fe(3+), K(+) and Mg(2+) ions in 9a-HSA system could increase the concentration of free 9a, shorten its storage time and half-life in the blood, thus improving its antimicrobial efficacy. PMID:24291568

Yin, Ben-Tao; Yan, Cong-Yan; Peng, Xin-Mei; Zhang, Shao-Lin; Rasheed, Syed; Geng, Rong-Xia; Zhou, Cheng-He

2014-01-01

386

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

387

Antimicrobial Peptides Design by Evolutionary Multiobjective Optimization  

PubMed Central

Antimicrobial peptides (AMPs) are an abundant and wide class of molecules produced by many tissues and cell types in a variety of mammals, plant and animal species. Linear alpha-helical antimicrobial peptides are among the most widespread membrane-disruptive AMPs in nature, representing a particularly successful structural arrangement in innate defense. Recently, AMPs have received increasing attention as potential therapeutic agents, owing to their broad activity spectrum and their reduced tendency to induce resistance. The introduction of non-natural amino acids will be a key requisite in order to contrast host resistance and increase compound's life. In this work, the possibility to design novel AMP sequences with non-natural amino acids was achieved through a flexible computational approach, based on chemophysical profiles of peptide sequences. Quantitative structure-activity relationship (QSAR) descriptors were employed to code each peptide and train two statistical models in order to account for structural and functional properties of alpha-helical amphipathic AMPs. These models were then used as fitness functions for a multi-objective evolutional algorithm, together with a set of constraints for the design of a series of candidate AMPs. Two ab-initio natural peptides were synthesized and experimentally validated for antimicrobial activity, together with a series of control peptides. Furthermore, a well-known Cecropin-Mellitin alpha helical antimicrobial hybrid (CM18) was optimized by shortening its amino acid sequence while maintaining its activity and a peptide with non-natural amino acids was designed and tested, demonstrating the higher activity achievable with artificial residues. PMID:24039565

Maccari, Giuseppe; Di Luca, Mariagrazia; Nifosi, Riccardo; Cardarelli, Francesco; Signore, Giovanni; Boccardi, Claudia; Bifone, Angelo

2013-01-01

388

Antimicrobial properties of honey.  

PubMed

Honey has been widely accepted as food and medicine by all generations, traditions, and civilizations, both ancient and modern. For at least 2700 years, honey has been used by humans to treat a variety of ailments through topical application, but only recently have the antiseptic and antimicrobial properties of honey been discovered. Honey has been reported to be effective in a number of human pathologies. Clinical studies have demonstrated that application of honey to severely infected cutaneous wounds rapidly clears infection from the wound and improves tissue healing. A large number of in vitro and limited clinical studies have confirmed the broad-spectrum antimicrobial (antibacterial, antifungal, antiviral, and antimycobacterial) properties of honey, which may be attributed to the acidity (low pH), osmotic effect, high sugar concentration, presence of bacteriostatic and bactericidal factors (hydrogen peroxide, antioxidants, lysozyme, polyphenols, phenolic acids, flavonoids, methylglyoxal, and bee peptides), and increase in cytokine release, and to immune modulating and anti-inflammatory properties of honey; the antimicrobial action involves several mechanisms. Despite a large amount of data confirming the antimicrobial activity of honey, there are no studies that support the systemic use of honey as an antibacterial agent. PMID:23782759

Israili, Zafar H

2014-01-01

389

Antimicrobial and cytotoxic activity of 18 prenylated flavonoids isolated from medicinal plants: Morus alba L., Morus mongolica Schneider, Broussnetia papyrifera (L.) Vent, Sophora flavescens Ait and Echinosophora koreensis Nakai  

Microsoft Academic Search

Antimicrobial activity of the 18 prenylated flavonoids, which were purified from five different medicinal plants, was evaluated by determination of MIC using the broth microdilution methods against four bacterial and two fungal microorganisms (Candida albicans, Saccaromyces cerevisiae, Escherichia coli, Salmonella typhimurium, Staphylococcus epidermis and S. aureus). Papyriflavonol A, kuraridin, sophoraflavanone D and sophoraisoflavanone A exhibited a good antifungal activity with

H.-Y. Sohn; K. H. Son; C.-S. Kwon; G.-S. Kwon; S. S. Kang

2004-01-01

390

Host plant oviposition preference of Ceratapion basicorne (Coleoptera: Apionidae), a potential biological control agent of yellow starthistle  

Microsoft Academic Search

Ceratapion basicorne is a weevil native to Europe and western Asia that is being evaluated as a prospective classical biological control agent of Centaurea solstitialis (yellow starthistle) in the United States. Choice oviposition experiments were conducted under laboratory conditions to help assess host plant specificity of the insect. Mean oviposition rates were highest on C. solstitialis (66% of eggs, on

Lincoln Smith

2012-01-01

391

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

392

An in-vitro evaluation of the efficacy of garlic extract as an antimicrobial agent on periodontal pathogens: A microbiological study.  

PubMed

With the rise in bacterial resistance to antibiotics, there is considerable interest in the development of other classes of antimicrobials for the control of infection. Garlic (Allium sativum Linn.) has been used as medicine since ancient times and has long been known to have antibacterial, antifungal, and antiviral properties. This study was undertaken to assess the inhibitory effect of garlic on Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, to assess the time-kill curve of P. gingivalis and A. actinomycetemcomitans, and to determine the antiproteolytic activity of garlic on P. gingivalis. Ethanolic garlic extract (EGE) and aqueous garlic extract (AGE) were prepared and the inhibitory effects of these extracts for two periodontal pathogens (P. gingivalis and A. actinomycetemcomitans) were tested. Antiproteolytic activity on protease of P. gingivalis was determined. 25 microliter (?l), 50 ?l, and 75 ?l of AGE showed 16 mm, 20 mm, and 25 mm zone of inhibition, respectively, on P. gingivalis. The AGE showed greater bacteriostatic activity against the P. gingivalis with minimum inhibitory concentration determined at 16.6 ?l/ml. The time-kill assay of AGE and EGE were compared for P. gingivalis and A. actinomycetemcomitans. AGE showed better antiproteolytic activity on total protease of P. gingivalis compared to the EGE. Thus, the study concludes the antimicrobial activity of garlic extract against periodontal pathogens, P. gingivalis, A. actinomycetemcomitans. Its action against P. gingivalis includes inhibition of total protease activity, and this raises the possibility that garlic may have therapeutic use for periodontitis and possibly other oral infections. PMID:24695825

Shetty, Sunaina; Thomas, Biju; Shetty, Veena; Bhandary, Rahul; Shetty, Raghavendra M

2013-10-01

393

Effect of efflux pump inhibitors on antimicrobial resistance and in vivo colonization of Campylobacter jejuni  

E-print Network

and proven to potentiate the activity of antimicrobial agents against Gram-negative bacteria. We demonstratedEffect of efflux pump inhibitors on antimicrobial resistance and in vivo colonization spectrum of antimicrobial agents and is also essential for Campylobacter colonization by mediation of bile

Grissino-Mayer, Henri D.

394

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

395

Synthesis and biological evaluation of novel N-substituted 1H-dibenzo[a,c]carbazole derivatives of dehydroabietic acid as potential antimicrobial agents.  

PubMed

A series of new N-substituted 1H-dibenzo[a,c]carbazole derivatives were synthesized from dehydroabietic acid, and their structures were characterized by IR, (1)H NMR and HRMS spectral data. All compounds were evaluated for their antibacterial and antifungal activities against four bacteria (Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas fluorescens) and three fungi (Candida albicans, Candida tropicalis and Aspergillus niger) by serial dilution technique. Some of the synthesized compounds displayed pronounced antimicrobial activity against tested strains with low MIC values ranging from 0.9 to 15.6?g/ml. Among them, compounds 6j and 6r exhibited potent inhibitory activity comparable to reference drugs amikacin and ketoconazole. PMID:24300736

Gu, Wen; Qiao, Chao; Wang, Shi-Fa; Hao, Yun; Miao, Ting-Ting

2014-01-01

396

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

397

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

398

Chemogeography and antimicrobial activity of essential oils from Geijera parviflora and Geijera salicifolia (Rutaceae): two traditional Australian medicinal plants.  

PubMed

Essential oils were hydrodistilled from 27 specimens of Geijera parviflora Lindl., (Rutaceae) and nine specimens of Geijera salicifolia Schott, collected over a wide geographic range in New South Wales, Queensland and South Australia. Essential oils were produced by traditional hydrodistillation and characterised using GC-MS. From one specimen a serendipitous discovery was made of bioactive coumarins dissolved in the hydrosol, which were the coumarins isopsoralen, xanthyletine and osthole. These coumarins were not present in the essential oil from that specimen. Using essential oil composition from all specimens, principal component analysis (PCA) demonstrated nine clusters for G. parviflora and three for G. salicifolia. Some clusters are representative of previously described chemotypes and some are reflective of possible chemotypes requiring more comprehensive sampling for confirmation. Thus, another three or four possible chemotypes of G. parviflora and one of G. salicifolia have been tentatively identified. Using micro-titre plate broth dilution assays, antibacterial and antifungal activity of all chemotypes was investigated. In this regard, the 'green oil' chemotype, restricted to G. parviflora, with major components linalool, geijerene/pregeijerene, 1,8-cineol and bicyclogermacrene, demonstrated the highest antimicrobial and free radical scavenging activity. Thus, in the light of traditional use reports of local analgaesia and bioactivity demonstrated in the current study, oils from select chemotypes of G. parviflora may be useful in suitably compounded lotions and creams designed for topical antimicrobial applications and local pain relief. In addition, because major components are known for insecticidal activities, such lotions may also be useful as topically applied insect repellents. PMID:24878365

Sadgrove, Nicholas J; Gonçalves-Martins, Maximilien; Jones, Graham L

2014-08-01

399

Antimicrobial activity and probable mechanisms of action of medicinal plants of Kenya: Withania somnifera, Warbugia ugandensis, Prunus africana and Plectrunthus barbatus.  

PubMed

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

400

Selection of a Surrogate Agent (Vancomycin or Teicoplanin) for Initial Susceptibility Testing of Dalbavancin: Results from an International Antimicrobial Surveillance Program  

PubMed Central

The immediate lack of market-dominating commercial products (Vitek or MicroScan) for susceptibility testing of the new glycolipopeptide, dalbavancin, requires a surrogate marker agent to assist microbiologists in the correct categorization of potentially indicated species (staphylococci and streptococci). Error-rate analyses for 16,749 isolates using vancomycin or teicoplanin results to categorize dalbavancin susceptibilities demonstrated that both glycopeptide agents were highly predictive of dalbavancin-susceptible results (nearly 100%) with only a rare minor error. Vancomycin test results most reliably predict dalbavancin susceptibility until validated commercial reagents become available for direct testing in clinical practice. PMID:16825398

Jones, Ronald N.; Sader, Helio S.; Fritsche, Thomas R.; Hogan, Patricia A.; Sheehan, Daniel J.

2006-01-01