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Plants produce a diverse array of secondary metabolites, many of which have antimicrobial activity. Some of this compounds are constitutive, existing in healthy plants in their biologically active forms. Others such as cyanogenic glycosides and glucosinolates, occur as inactive precursors and are activated in response to tissue damage or pathogen attack.
Microbial contamination of ophthalmic drops means a risk of serious injury to the eye. Ophthalmic drops must therefore comply with sterility requirements. Protection of multiple-dose drops against secondary contamination is ensured by an addition of an antimicrobialagent. Selection of a suitable antimicrobialagent is conditioned by many factors, such as the spectrum of effect, properties of the preparation, compatibility with the components of the preparation and the container, and the technology of manufacture. Although the added antimicrobial substance ensures the safety of the preparation, on the other hand it can produce a number of negative effects in the eye tissue. The present paper summarizes pharmacopoeial requirements for microbial quality of ophthalmic drops, outlining the properties and efficacy of antimicrobial substances commonly used in ophthalmic drops (benzalkonium chloride BAC, cetrimide CTM, phenyl mercuric salts PHg, thiomersal TM, chlorobutanol ChB, benzyl alcohol BA, phenyl ethyl alcohol PEA, chlorohexidin ChX, parabens PB), their typical concentrations and combinations, including the parameters of formulation and the interactions which affect their activity. It deals with the toxicity of these antimicrobial substances, side effects on the eye tissue, and alternatives to the use of antimicrobialagents. PMID:15218731
Infections caused by multidrug-resistant bacteria are an increasing problem due to the emergence and propagation of microbial drug resistance and the lack of development of new antimicrobials. Traditional methods of antibiotic discovery have failed to keep pace with the evolution of resistance. Therefore, new strategies to control bacterial infections are highly desirable. Plant secondary metabolites (phytochemicals) have already demonstrated their potential as antibacterials when used alone and as synergists or potentiators of other antibacterial agents. The use of phytochemical products and plant extracts as resistance-modifying agents (RMAs) represents an increasingly active research topic. Phytochemicals frequently act through different mechanisms than conventional antibiotics and could, therefore be of use in the treatment of resistant bacteria. The therapeutic utility of these products, however, remains to be clinically proven. The aim of this article is to review the advances in in vitro and in vivo studies on the potential chemotherapeutic value of phytochemical products and plant extracts as RMAs to restore the efficacy of antibiotics against resistant pathogenic bacteria. The mode of action of RMAs on the potentiation of antibiotics is also described. PMID:22786554
Abreu, Ana Cristina; McBain, Andrew J; Simőes, Manuel
Antimicrobial host defense peptides are produced by all complex organisms as well as some microbes and have diverse and complex antimicrobial activities. Collectively these peptides demonstrate a broad range of antiviral and antibacterial activities and modes of action, and it is important to distinguish between direct microbicidal and indirect activities against such pathogens. The structural requirements of peptides for antiviral and antibacterial activities are evaluated in light of the diverse set of primary and secondary structures described for host defense peptides. Peptides with antifungal and antiparasitic activities are discussed in less detail, although the broad-spectrum activities of such peptides indicate that they are important host defense molecules. Knowledge regarding the relationship between peptide structure and function as well as their mechanism of action is being applied in the design of antimicrobial peptide variants as potential novel therapeutic agents.
Jenssen, Havard; Hamill, Pamela; Hancock, Robert E. W.
Peptides with antimicrobial properties are present in most if not all plant species. All plantantimicrobial peptides isolated so far contain even numbers of cysteines (4, 6, or 8), which are all pairwise connected by disulfide bridges, thus providing high stability to the peptides. Based on homologies at the primary structure level, plantantimicrobial peptides can be classified into distinct
Willem F. Broekaert; Bruno P. A. Cammue; Miguel F. C. De Bolle; Karin Thevissen; Genoveva W. De Samblanx; Rupert W. Osborn; K. Nielson
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
The limitations of current antimicrobials for highly virulent pathogens considered as potential bioterrorism agents drives the requirement for new antimicrobials that are suitable for use in populations in the event of a deliberate release. Strategies targeting bacterial virulence offer the potential for new countermeasures to combat bacterial bioterrorism agents, including those active against a broad spectrum of pathogens. Although early in the development of antivirulence approaches, inhibitors of bacterial type III secretion systems and cell division mechanisms show promise for the future. PMID:21707313
SUMMARY New antimicrobialagents are always needed to counteract the resistant pathogens that continue to be selected by current therapeutic regimens. This review provides a survey of known antimicrobialagents 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 antimicrobialagents 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
The use of edible coating has proved a valuable tool in improving the efficiency of osmotic dehydration (OD) of plant material. In this study the impact of edible coating with or without an anti-microbialagent (A–M) on microbial growth was investigated. Potato cylinders (15×57 mm — D×L) were used as a model plant material. Calcium alginate (CA) coating was applied with
G. E. Mitrakas; K. P. Koutsoumanis; H. N. Lazarides
This review article deals with the structure activity relationship (SAR) for a variety of palladacycles in biomedical applications. Moreover, the types of antibacterial, antifungal, antimycobacterial and antiprotozoal (antiamoebic and antitrypanosomal) activities will vary considerably from one country to another. Therefore, all efforts will be required to face such a vast diversity of problems. This study gives an up to date overview of the antibacterial, antifungal, antimycobacterial and antiprotozoal chemistry of the palladium group elements with an emphasis on the new strategies used in the development of new antibacterial agents. Methodologies for application of bulky aromatic or aliphatic nitrogen ligands, chiral organic moieties, chelates containing other donor atoms than nitrogen, and biologically active ligands in the design of agents analogous to palladacycles are presented. Therefore, the use of palladacycles in medicinal chemistry is interesting as potential application in the biological properties with less toxic drugs compounds.. PMID:22612708
Elgazwy, A-S S H; Ismail, N S M; Atta-Allah, S R; Sarg, M T; Soliman, D H S; Zaki, M Y; Elgamas, M A
Several antiarrhythmic and non-cardiovascular drug therapies including antimicrobialagents 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
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 antimicrobialagent, they may reverse resistance in a synergistic fashion. PMID:22536197
Antimicrobial research is geared toward the discovery and development of novel chemical structures such as therapeutic antimicrobialagents. 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
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.
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 antimicrobialagents.
Kim, Jin-Young; Park, Seong-Cheol; Hwang, Indeok; Cheong, Hyeonsook; Nah, Jae-Woon; Hahm, Kyung-Soo; Park, Yoonkyung
In the present review article, the penetration of antimicrobialagents into prostatic fluid and tissue was examined. Three major factors determining the diffusion and concentration of antimicrobialagents in prostatic fluid and tissue are the lipid solubility, dissociation constant (pKa) and protein binding. The normal pH of human prostatic fluid is 6.5-6.7, and it increases in chronic prostatitis, ranging from 7.0 to 8.3. A greater concentration of antimicrobialagents in the prostatic fluid occurs in the presence of a pH gradient across the membrane separating plasma from prostatic fluid. Of the available antimicrobialagents, beta-lactam drugs have a low pKa and poor lipid solubility, and thus penetrate poorly into prostatic fluid, expect for some cephalosporins, which achieve greater than or equal to the inhibitory concentration. Good to excellent penetration into prostatic fluid and tissue has been demonstrated with many antimicrobialagents, including tobramycin, netilmicin, tetracyclines, macrolides, quinolones, sulfonamides and nitrofurantoin. PMID:14671426
Silicone gel sheets containing Ofloxacin (OFLX), that provide a continual drug delivery system from a wound dressing to the wound so as to prevent infection and to promote healing, are described. It was found that silicone gel sheets without added medication did not inhibit microbial growth but that gel sheets containing 0.02% and 0.2% of OFLX had a positive antimicrobial effect against Staphylococcus aureus and Pseudomonas aeruginosa in a dose-dependent fashion in vitro. Further, this antimicrobial efficacy was greatly increased in a silicone gel sheet that contained 0.02% of OFLX and an additional 10% of silicone oil. In animal experiments, a silicone gel sheet containing OFLX prevented microbiol growth and promoted rapid epithelialisation in wounds to which Staphylococcus aureus had been applied, whereas wounds covered only with OpSite all resulted in continued infection. PMID:2107010
2 Abstract: The use of Xenoprotec in medical purposes as new antimicrobialagent with low production cost and affecting antibiotic resistant bacteria as Staphylococcus aureus and Pseudomonas fluresence had been carried out. Four bacterial strains were isolated (Xenorhabdus indica, Xenorhabdus nematophila, Xenorhabdus sp. and Photorhabdus lumenscens laumondii) from the four entomopathogenic nematodes species, Steinernema abbasi, Steinernema carpocapsae DD , Steinernema
This study has been carried out to evaluate the possible In vitro interaction between ethanolic extracts of Rus coriaria (seed), Sacropoterium spinosum (seed) and Rosa damascena (flower) and certain known antimicrobial drugs including oxytetracycline HCl, penicillin G, cephalexin, sulfadimethoxine as sodium and enrofloxacin. Synergy testing of these extracts and antibiotics was carried out against 3 multidrug-resistant Pseudomonas aeruginosa strains using
Cephalosporins are broad-spectrum antimicrobialagents that are often used empirically to treat suspected bacterial infections and also to treat culture-proven infections due to selected gram-positive and gram-negative microorganisms. Cephalosporins differ widely in their spectrum of activity, susceptibility to beta-lactamases, serum half-life, and penetration of the central nervous system. In general, the first-generation and second-generation agents are most active against staphylococci and streptococci, and the third-generation agents are most active against the Enterobacteriaceae and Pseudomonas. As a group, cephalosporins have a favorable profile of toxicity in comparison with other antimicrobialagents. The development of bacterial resistance has affected all steps of the cephalosporin mechanism of action, including production of beta-lactamases, alterations in penicillin-binding proteins, and modification of the cell wall. New cephalosporins are among the most expensive pharmaceutical agents in use today. Maintaining expertise in the choice and use of these agents will remain a challenge to physicians as additional investigational cephalosporins continue to be developed and introduced into clinical practice. PMID:1921490
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 antimicrobialagents. 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
Three novel deoxyribofuranosyl indole derivatives, FG050227 (1), FG050223 (2) and FG050204 (3), were identified as antimicrobialagents effective against Gram-positive bacterial strains and some fungi. The MIC values of (1), (2) and (3) against methicillin-resistant Staphylococcus aureus were 3.0, 6.0 and 13 ?g ml?1, respectively. Compounds 1 and 3 had bactericidal activity against exponentially growing S. aureus and inhibited biosynthesis
Various antimicrobialagents were evaluated with the purpose of reducing the microbial fermentation in stored cattle waste and the resulting odor emissions. Duplicate sealed 2-L flasks with 500 ml waste slurry, with and without antimicrobial inhibitors, were used to measure the production of short-chain volatile fatty acids, lactate, and total fermentation gas over 27-30 days. A combination of chlorhexidine diacetate (2 mM), iodoacetate (2 mM), and alpha-pinene (3.8 mM) reduced gas production 80% (1000 ml to 200 ml) and total volatile fatty acid production 50% (145 mM to 72 mM). Pinene had little antimicrobial effect; rather, it served as an effective masking agent, giving the waste a less offensive odor. A combination of chlorhexidine diacetate and the deaminase inhibitor, diphenyliodonium chloride (1.3 mM) had a similar effect in reducing short-chain volatile fatty acid production (145 mM to 80 mM). It is concluded that a combination of antimicrobialagents may be useful in controlling odor emissions and conserving organic matter in livestock wastes, therefore providing a potentially more useful byproduct waste when used as plant fertilizer. PMID:10827282
The aim of this study was to find an alternative to synthetic fungicides currently used in the control of devastating oomycete pathogen Phytophthora infestans, causal agent of late blight disease of tomato. Antifungal activities of essential oils obtained from aerial parts of aromatic plants such as oregano (Origanum syriacum var. bevanii), thyme (Thymbra spicata subsp. spicata), lavender (Lavandula stoechas subsp. stoechas), rosemary (Rosmarinus officinalis), fennel (Foeniculum vulgare), and laurel (Laurus nobilis), were investigated against P. infestans. Both contact and volatile phase effects of different concentrations of the essential oils used were determined by using two in vitro methods. Chemical compositions of the essential oils were also determined by GC-MS analysis. Major compounds found in essential oils of thyme, oregano, rosemary, lavender, fennel and laurel were carvacrol (37.9%), carvacrol (79.8), borneol (20.4%), camphor (20.2%), anethole (82.8%) and 1,8-cineole (35.5%), respectively. All essential oils were found to inhibit the growth of P. infestans in a dose-dependent manner. Volatile phase effect of oregano and thyme oils at 0.3 microg/ml air was found to completely inhibit the growth of P. infestans. Complete growth inhibition of pathogen by essential oil of fennel, rosemary, lavender and laurel was, however, observed at 0.4-2.0 microg/ml air concentrations. For the determination of the contact phase effects of the tested essential oils, oregano, thyme and fennel oils at 6.4 microg/ml were found to inhibit the growth of P. infestans completely. Essential oils of rosemary, lavender and laurel were inhibitory at relatively higher concentrations (12.8, 25.6, 51.2 microg/ml respectively). Volatile phase effects of essential oils were consistently found to be more effective on fungal growth than contact phase effect. Sporangial production was also inhibited by the essential oil tested. Light and scanning electron microscopic (SEM) observation on pathogen hyphae, exposed to both volatile and contact phase of oil, revealed considerable morphological alterations in hyphae such as cytoplasmic coagulation, vacuolations, hyphal shrivelling and protoplast leakage. PMID:16463095
The endotoxin from gram-negative bacteria consists of a molecule lipopolysaccharide (LPS) which can be shed by bacteria during antimicrobial therapy. A resulting syndrome, endotoxic shock, is a leading cause of death in the developed world. Thus, there is great interest in the development of antimicrobialagents which can reverse rather than promote sepsis, especially given the recent disappointing clinical performance of antiendotoxin therapies. We describe here two small cationic peptides, MBI-27 and MBI-28, which have both antiendotoxic and antibacterial activities in vitro and in vivo in animal models. We had previously demonstrated that these peptides bind to LPS with an affinity equivalent to that of polymyxin B. Consistent with this, the peptides blocked the ability of LPS and intact cells to induce the endotoxic shock mediator, tumor necrosis factor (TNF), upon incubation with the RAW 264.7 murine macrophage cell line. MBI-28 was equivalent to polymyxin B in its ability to block LPS induction of TNF by this cell line, even when added 60 min after the TNF stimulus. Furthermore, MBI-28 offered significant protection in a galactosamine-sensitized mouse model of lethal endotoxic shock. This protection correlated with the ability of MBI-28 to reduce LPS-induced circulating TNF by nearly 90% in this mouse model. Both MBI-27 and MBI-28 demonstrated antibacterial activity against gram-negative bacteria in vitro and in vivo against Pseudomonas aeruginosa infections in neutropenic mice.
Alkyldimethylsilanols, R(CH3)2SiOH, were recently reported to exhibit unexpectedly strong antimicrobial effects. The antimicrobial activities of alkyldimethylsilanols were significantly higher than their analogous alcohols. A study of structural dependenc...
Infectious diseases account for approximately one-half of all deaths in tropical countries. In industrial-ized nations, despite the progress made in the understanding of microbiology and their control, incidents of epidemics due to drug resistant microorganisms and the emergence of hitherto unknown disease-causing mi-crobes, pose enormous public health concerns. Historically, plants have provided a good source of antiinfective agents; emetine, quinine,
There is cumulative resistance against antibiotics of many bacteria. Therefore, the development of new antiseptics and antimicrobialagents for the treatment of skin infections is of increasing interest. We have screened six plant extracts and isolated compounds for antimicrobial effects on bacteria and yeasts with dermatological relevance. The following plant extracts have been tested: Gentiana lutea, Harpagophytum procumbens, Boswellia serrata
S. Weckesser; K. Engel; B. Simon-Haarhaus; A. Wittmer; K. Pelz; C. M. Schempp
Antimicrobial peptides (AMPs) secreted by the innate immune system are prevalent as the effective first-line of defense to overcome recurring microbial invasions. They have been widely accepted as the blueprints for the development of new antimicrobialagents for the treatment of drug resistant infections. However, there is also a growing concern that AMPs with a sequence that is too close
Nikken Wiradharma; Ulung Khoe; Charlotte A. E. Hauser; See Voon Seow; Shuguang Zhang; Yi-Yan Yang
Inhaled antimicrobialagents are used for the treatment of respiratory tract infections due to Gram-negative bacteria, mainly Pseudomonas aeruginosa. The effectiveness of the inhaled antimicrobial therapy is believed to correlate with the delivery system used. The objective of this review was to search for data supporting differentiation in clinical effectiveness between systems used for pulmonary delivery of antibiotics, including delivery
Matthew E. Falagas; Argyris Michalopoulos; Eugenios I. Metaxas
The aquaculture industry has grown dramatically, and plays an important role in the world's food supply chain. Antimicrobial resistance in bacteria associated with food animals receives much attention, and drug use in aquaculture is also an important issue. There are many differences between aquatic and terrestrial management systems, such as the methods used for administration of drugs. Unique problems are related to the application of drugs in aquatic environments. Residual drugs in fish products can affect people who consume them, and antimicrobials released into aquatic environments can select for resistant bacteria. Moreover, these antimicrobial-resistant bacteria, or their resistance genes, can be transferred to humans. To decrease the risks associated with the use of antimicrobials, various regulations have been developed. In addition, it is necessary to prevent bacterial diseases in aquatic animals by vaccination, to improve culture systems, and to monitor the amount of antimicrobial drugs used and the prevalence of antimicrobial-resistant bacteria. PMID:22849275
Antimicrobialagents, systemic and/or local, are thought by some to be effective agents for treating periodontal infections. Here the authors determine the costs and benefits of local delivery agents for treating periodontal disease. Applying this cost-benefit analysis to patient care, however, will depend upon a clinician's expertise and a patient's value system. PMID:12436823
Niederman, Richard; Abdelshehid, George; Goodson, J Max
Artemisia pallens Wall, a medicinally important plant, belongs to family Asteraceae. It is This plant is used in Ayurvedic system of medicines. In order to search for antimicrobial activity of secondary metabolites, screening of aerial parts of A. pallens was carried out. Air shade dried powdered plant material was extracted using solvents of increasing polarity from non polar ( n-hexane
Anjali D. Ruikar; Gayatri S. Kamble; Vedavati G. Puranik; Nirmala R. Deshpande
This work describes the de-novo design of peptides that inhibit a broad range of plant pathogens. Four structurally different groups of peptides were developed that differ in size and position of their charged and hydrophobic clusters and were assayed for their ability to inhibit bacterial growth and fungal spore germination. Several peptides are highly active at concentrations between 0,1 and 1 µg/ml against plant pathogenic bacteria, such as Pseudomonas syringae, Pectobacterium carotovorum, and Xanthomonas vesicatoria. Importantly, no hemolytic activity could be detected for these peptides at concentrations up to 200 µg/ml. Moreover, the peptides are also active after spraying on the plant surface demonstrating a possible way of application. In sum, our designed peptides represent new antimicrobialagents and with the increasing demand for antimicrobial compounds for production of "healthy" food, these peptides might serve as templates for novel antibacterial and antifungal agents. PMID:23951222
This work describes the de-novo design of peptides that inhibit a broad range of plant pathogens. Four structurally different groups of peptides were developed that differ in size and position of their charged and hydrophobic clusters and were assayed for their ability to inhibit bacterial growth and fungal spore germination. Several peptides are highly active at concentrations between 0,1 and 1 µg/ml against plant pathogenic bacteria, such as Pseudomonas syringae, Pectobacterium carotovorum, and Xanthomonas vesicatoria. Importantly, no hemolytic activity could be detected for these peptides at concentrations up to 200 µg/ml. Moreover, the peptides are also active after spraying on the plant surface demonstrating a possible way of application. In sum, our designed peptides represent new antimicrobialagents and with the increasing demand for antimicrobial compounds for production of “healthy” food, these peptides might serve as templates for novel antibacterial and antifungal agents.
The in vitro susceptibilities of 145 Photobacterium damselae subsp. piscicida strains, isolated from different geographical regions, against 15 major fish farming antimicrobialagents were assessed using a disc diffusion method. Ninety-nine percent of all isolates were sensitive to florfenicol and trimethoprime-sulfamethoxazole; 93% of the strains were resistant to erythromycin. Based on the antimicrobial susceptibility, the P. damselae subp. piscicida isolates
Propionibacterium acnes and Staphylococcus epidermidis have been recognized as pus-forming bacteria triggering an inflammation in acne. The present study was conducted to evaluate antimicrobial activities of Thai medicinal plants against these etiologic agents of acne vulgaris. Crude extracts were tested for antimicrobial activities by disc diffusion and broth dilution methods. The results from the disc diffusion method showed that 13
Mullika Traidej Chomnawang; Suvimol Surassmo; Veena S. Nukoolkarn; Wandee Gritsanapan
Kimchi is a traditional Korean fermented food. Since it ferments continuously during distribution and storage, the extension of shelf life by preventing over-acidification is a major concern in the kimchi industry. One of the most frequently attempted ways to delay fermentation is to add naturally occurring antimicrobialagents. Many researchers have investigated ways to delay over-acidification by adding minor ingredients, fruits or fruit seed extracts, extracts of medicinal herbs, culinary herbs and spices, and other miscellaneous substances to kimchi. The addition of naturally occurring antimicrobialagents may enhance the acceptability of kimchi to consumers over a longer period of time but may also have a disadvantage in that it may cause changes in sensory quality, especially if added in large amounts. To avoid undesirable sensory changes, application of hurdle technologies (i.e., multifactor preservative systems) which involve using combinations of low amounts of various naturally occurring antimicrobialagents as ingredients should be explored with the goal of controlling fermentation. If synergistic or additive antimicrobial effects can be achieved using small amounts of a combination of natural agents, changes in sensory qualities will be minimized, thereby prolonging shelf life. Research findings summarized in this review provide a basis for developing effective hurdle technologies using naturally occurring antimicrobialagents to extend shelf life of kimchi and perhaps other types of traditional fermented foods. PMID:22850370
Kim, Jinsol; Bang, Jihyun; Beuchat, Larry R; Kim, Hoikyung; Ryu, Jee-Hoon
2-Dichloroamino-2-methyl-propane-1-sulfonic acid sodium salt (2a), a stable derivative of endogenous N,N-dichlorotaurine (1), has been identified and is under development as a topical antimicrobialagent. Structure-activity relationships of analogs were explored to achieve optimal antimicrobial activity with minimal mammalian toxicity while maintaining the desired stability. All the analogs synthesized showed antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans in the range of 1-128 microg/mL and cytotoxicity against mammalian L929 cells in the range 80-1900 microg/mL. PMID:19010674
Chitosan (CS) is a linear polysaccharide with good biodegradability, biocompatibility and antimicrobial activity, which makes it potentially useful for biomedical applications, including an antimicrobialagent either alone or blended with other polymers. However, the poor solubility of CS in most solvents at neutral or high pH substantially limits its use. Quaternary ammonium CS, which was prepared by introducing a quaternary ammonium group on a dissociative hydroxyl group or amino group of the CS, exhibited improved water solubility and stronger antibacterial activity relative to CS over an entire range of pH values; thus, this quaternary modification increases the potential biomedical applications of CS in the field of anti-infection. This review discusses the current findings on the antimicrobial properties of quaternized CS synthesized using different methods and the mechanisms of its antimicrobial actions. The potential antimicrobial applications in the orthopedic field and perspectives regarding future studies in this field are also considered.
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
Thirty-three isolates of Legionella pneumophila, all except one of which were clinical isolates, were tested against 20 antimicrobialagents by using an agar dilution technique. Erythromycin, rifamp]in, and rosaramycin were the most active agents tested. Aminoglycosides, chloramphenicol, and cefoxitin also inhibited the organisms at low concentrations. Other agents, including moxalactam, cefoperazone, and cephalosporins, exhibited moderate to little activity. Tetracycline, doxycycline and minocyeline were apparently inactivated by charcoal-yeast extract medium. There was slight inoculum dependence noted with most of the antimicrobials tested, particularly the beta-lactam agents. There was no consistent difference in susceptibility between Center for Disease Control-supplied stock strains and recent clinical isolates, but there were marked differences with some agents. Susceptibility testing needs to be standardized in view of the influence of inoculum size, strain variation, and the medium used.
The author reviews his research, since 1966, for the ideal germicide. The relationship between structure of fatty acids, their\\u000a corresponding esters, and antimicrobial activity is presented. Saturated fatty acids have their highest activity when the\\u000a chain length is twelve carbons (C12) long; monounsaturated fatty acids reach their peak with palmitoleic acid (C16?1); the most active polyunsaturated fatty acid is linoleic.Trans
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
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 antimicrobialagents. PMID:19168430
Antimicrobialagents are toxic to bacteria by a variety of mechanisms. One mechanism that is very dependent on the lipid composition\\u000a of the bacterial membrane is the clustering of anionic lipid by cationic antimicrobialagents. Certain species of oligo-acyl-lysine\\u000a (OAK) antimicrobialagents are particularly effective in clustering anionic lipids in mixtures mimicking the composition of\\u000a bacterial membranes. The clustering of
The minimum inhibitory concentration (MIC) values for 124 strains of Yersinia ruckeri were determined. The effects of oxolinic acid, oxytetracycline and a potentiated sulphonamide, on growth patterns over a 72-h period, were also determined. Results showed the bactericidal or bacteriostatic nature of each antimicrobialagent, which were confirmed by estimating the minimum bactericidal concentration (MBC). In addition, it was possible
With growing concerns over multidrug resistance microorganisms, particularly strains of bacteria and fungi, evolving to become resistant to the antimicrobialagents 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
Ninety-two strains of Yersinia pestis recovered over a 21-year period were evaluated for susceptibility to traditional and newer antimicrobialagents. In vitro resistance was noted only against rifampin and imipenem (approximately 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
Nuclear medicine imaging techniques offer whole body imaging for localization of number and site of infective foci inspite of limitation of spatial resolution. The innate human immune system contains a large member of important elements including antimicrobial peptides to combat any form of infection. However, development of antibiotics against bacteria progressed rapidly and gained popularity over antimicrobial peptides but even powerful antimicrobials failed to reduce morbidity and mortality due to emergence of mutant strains of bacteria resulting in antimicrobial resistance. Differentiation between infection and inflammation using radiolabeled compounds with nuclear medicine techniques has always been a dilemma which is still to be resolved. Starting from nonspecific tracers to specific radiolabeled tracers, the question is still unanswered. Specific radiolabeled tracers included antibiotics and antimicrobial peptides which bind directly to the bacteria for efficient localization with advanced nuclear medicine equipments. However, there are merits and demerits attributed to each. In the current paper, radiolabeled antibiotics and radiolabeled peptides for infection localization have been discussed starting with the background of primitive nonspecific tracers. Radiolabeled antimicrobial peptides have certain merits compared with labeled antibiotics which make them superior agents for localization of infective focus.
Akhtar, Muammad Saeed; Imran, Muhammad Babar; Nadeem, Muhammad Afzal; Shahid, Abubaker
Chemerin, a chemoattractant ligand for chemokine-like receptor 1 (CMKLR1) is predicted to share similar tertiary structure with antibacterial cathelicidins. Recombinant chemerin has antimicrobial activity. Here we show that endogenous chemerin is abundant in human epidermis, and that inhibition of bacteria growth by exudates from organ cultures of primary human skin keratinocytes is largely chemerin-dependent. Using a panel of overlapping chemerin-derived synthetic peptides, we demonstrate that the antibacterial activity of chemerin is primarily mediated by Val(66)-Pro(85), which causes direct bacterial lysis. Therefore, chemerin is an antimicrobialagent in human skin. PMID:23527010
Chemerin, a chemoattractant ligand for chemokine-like receptor 1 (CMKLR1) is predicted to share similar tertiary structure with antibacterial cathelicidins. Recombinant chemerin has antimicrobial activity. Here we show that endogenous chemerin is abundant in human epidermis, and that inhibition of bacteria growth by exudates from organ cultures of primary human skin keratinocytes is largely chemerin-dependent. Using a panel of overlapping chemerin-derived synthetic peptides, we demonstrate that the antibacterial activity of chemerin is primarily mediated by Val66-Pro85, which causes direct bacterial lysis. Therefore, chemerin is an antimicrobialagent in human skin.
Since the beginning of the 1990s, the number of human cases of plague has been rising, and outbreaks are reappearing in various countries after decades of quiescence. Plague is there- fore categorized as a reemerging disease. Until recently, Yer- sinia pestis was considered as uniformly susceptible to agents that are active against gram-negative bacteria. The isolation in Madagascar of two
Marc Galimand; Elisabeth Carniel; Patrice Courvalin
Pyridinium oxime compounds have been utilised by a number of military organisations as one of the antidotes for nerve-agent poisoning. In Canada, the preferred compound from this class is HI-6, which has been demonstrated to be tolerated at high doses wit...
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
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-microbialagent, it is necessary to have knowledge of that agent. The aim of this review article is to provide basic details of each systemic anti-microbialagent 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-microbialagent. It might be of some help while prescribing these drugs.
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-microbialagent, it is necessary to have knowledge of that agent. The aim of this review article is to provide basic details of each systemic anti-microbialagent 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-microbialagent. It might be of some help while prescribing these drugs. PMID:23869120
Targeting of antimicrobialagents by means of liposomes is under investigation and may be of importance in the treatment of\\u000a infections that prove refractory to conventional forms of antimicrobial treatment. The ability to achieve a significantly\\u000a longer residence time of liposomes in plasma and limited uptake of liposomes by the mononuclear phagocyte system opens up\\u000a new areas of investigation and
I. A. J. M. Bakker-Woudenberg; A. F. Lokerse; M. T. ten Kate; P. M. B. Melissen; W. van Vianen; E. W. M. van Etten
The pathogenesis of implant-associated infection involves interaction between the microorganisms (biofilm formation), the implant and the host. Despite improvement of perioperative prophylaxis, orthopaedic implants still remain highly susceptible to bacterial or fungal contamination, generally resulting in persistent implant-associated infection. Therefore, perioperative and life-long prevention of infection is important. For perioperative prophylaxis, a first- or second-generation cephalosporin is recommended, which should be administered between 60 and 30 minutes before incision. The duration of prophylaxis should not exceed 1 day. In centres with a low incidence of infection, a single dose is sufficient. Treatment of infections associated with orthopaedic devices usually requires appropriate surgical intervention combined with prolonged antimicrobial therapy. The choice of the antimicrobial regimen depends on the duration and pathogenesis of infection, stability of the implant, antimicrobial susceptibility of the pathogen and condition of the surrounding soft tissue. The role of rifampicin (rifampin), which has excellent activity on adherent staphylococci, in combination with beta-lactams, glycopeptides, fluoroquinolones, minocycline, cotrimoxazole or fusidic acid, in the treatment of staphylococcal infections is outlined. Increasing antimicrobial resistance requires the use of alternative agents, such as quinupristin/dalfopristin, linezolid and daptomycin, but results of clinical trials with these agents are limited. Also reviewed are potential new antimicrobialagents currently undergoing investigation, such as the novel oxazolidinone RWJ-416457, the new glycopeptide dalbavancin, the glycylcycline compound tigecycline, the new carbacephem BP-102 and novel rifamycin derivatives. Vaccination against Staphylococcus aureus with StaphVAX induced specific antibodies potentially preventing bacteraemia; however, there are no studies on efficacy in the prophylaxis of device-associated infections with this vaccine. PMID:16789794
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
The antimicrobial potential of seventy-seven extracts from twenty-four plants was screened against eight bacteria and four pathogenic fungi, using microbroth dilution assay. Lowest concentration of the extract, which inhibits any visual microbial growth after treatment with p-iodonitrotetrazolium violet, was considered to be minimum inhibitory concentration (MIC). Water extracts of Acacia nilotica, Justicia zelanica, Lantana camara and Saraca asoca exhibited good activity against all the bacteria tested and the MIC was recorded in range of 9.375-37.5 microg/ml and 75.0-300.0 microg/ml against the bacterial and fungal pathogens, respectively. The other extracts of Phyllanthus urinaria, Thevetia nerifolia, Jatropha gossypifolia Saraca asoca, Tamarindus indica, Aegle marmelos, Acacia nilotica, Chlorophytum borivilianum, Mangifera indica, Woodfordia fruticosa and Phyllanthus emblica showed antimicrobial activity in a range of 75-1200 microg/ml. PMID:20161895
Dabur, Rajesh; Gupta, Amita; Mandal, T K; Singh, Desh Deepak; Bajpai, Vivek; Gurav, A M; Lavekar, G S
The antimicrobial activity of crude ethanolic extracts of 16 Siberian medicinal plants was tested against five species of microorganisms: Bacillus cereus, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. Of the 16 plants tested, 12 showed antimicrobial activity against one or more species of microorganisms. The most active antimicrobialplants were Bergenia crassifolia,Chelidonium majus,Rhaponticum carthamoides,Sanguisorba officinalis, and Tussilago farfara.
L. Kokoska; Z. Polesny; V. Rada; A. Nepovim; T. Vanek
The improved agar diffusion method for determination of residual antimicrobialagents was investigated, and the sensitivities of various combinations of test organisms and assay media were determined using 7 organisms, 5 media, and 31 antimicrobialagents. Bacillus stearothermophilus and synthetic assay medium (SAM) showed the greatest sensitivity for screening penicillins (penicillin G and ampicillin). The combination of Bacillus subtilis and minimum medium (MM) was the most sensitive for tetracyclines (oxytetracycline and chlortetracycline), B. stearothermophilus and SAM or Micrococcus luteus and Mueller-Hinton agar (MHA) for detecting tylosin and erythromycin, B. subtilis and MHA for aminoglycosides (streptomycin, kanamycin, gentamicin, and dihydrostreptomycin), B. stearothermophilus and SAM for polyethers (salinomycin and lasalocid), and B. subtilis and MM or Clostridium perfringens and GAM for polypeptides (thiopeptin, enramycin, virginiamycin, and bacitracin). However, gram-negative bacterium Escherichia coli ATCC 27166 and MM were better for screening for colistin and polymixin-B. For detecting the synthetic drugs tested, the best combination was B. subtilis and MM for sulfonamides, E. coli 27166 and MM for quinolones (oxolinic acid and nalidixic acid), B. subtilis and MM for furans (furazolidone), and the bioluminescent bacterium Photobacterium phosphoreum and luminescence assay medium for chloramphenicol and oxolinic acid. The results showed that the use of four assay plates, B. stearothermophilus and SAM, B. subtilis and MM, M. luteus and MHA, and E. coli 27166 and MM, was superior to the currently available techniques for screening for residual antimicrobialagents in edible animal tissues. PMID:11252480
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 antimicrobialagent for various infectious diseases.
Antimicrobialagent usage is common in animal agriculture for therapeutic and prophylactic purposes. Selective pressure exerted\\u000a by these antimicrobials on soil bacteria could result in the selection of strains that are resistant due to chromosomal- or\\u000a plasmid-derived genetic components. Multiple antimicrobial resistances in Escherichia coli and the direct relationship between antimicrobialagent use over time has been extensively studied, yet
Suzanna E. Jones; Jonathan M. Burgos; Marvin M. F. Lutnesky; Johnny A. Sena; Sanath Kumar; Lindsay M. Jones; Manuel F. Varela
source of new antimalarial drugs in view of the su ccess with the two important chemotherapeutic agents, quinine and artemisinin, both of which are de rived from plants. This article gives a critical account of crude extracts, e sse- ntial oil and active constituents with diverse chemical structures from higher plants possessing significant ant i- malarial activity, reported during last
Sudhanshu Saxena; Neerja Pant; D. C. Jain; R. S. Bhakuni
Inhaled antimicrobialagents are used for the treatment of respiratory tract infections due to Gram-negative bacteria, mainly Pseudomonas aeruginosa. The effectiveness of the inhaled antimicrobial therapy is believed to correlate with the delivery system used. The objective of this review was to search for data supporting differentiation in clinical effectiveness between systems used for pulmonary delivery of antibiotics, including delivery using disposable nebulisers and oxygen flow. Published studies in peer-reviewed journals comparing the effectiveness of pulmonary drug delivery systems for antimicrobialagents were retrieved. The studies found were either in vitro or Phase I and Phase II clinical studies. Differences in in vitro parameters may affect the in vivo efficacy of the devices, and in vivo differences may imply differences in clinical effectiveness. The main difference between newer and older devices is the time needed for antibiotic delivery. Interpretation and association with clinical effectiveness is difficult. In conclusion, Phase III clinical trials comparing the clinical effectiveness of delivery systems, including delivery using a hospital's oxygen flow and disposable nebulisers, do not exist. Cost is an important parameter, which may be counterbalanced in cystic fibrosis patients by a better quality of life and a greater adherence to treatment. PMID:19939637
Falagas, Matthew E; Michalopoulos, Argyris; Metaxas, Eugenios I
OBJECTIVE: To provide guidelines for antimicrobial prophylaxis on the basis of the type of surgical procedure. OPTIONS: Standard drug regimens for prophylaxis of infection in a variety of surgical procedures were considered, including a first-generation cephalosporin; an aminoglycoside in combination with metronidazole, clindamycin or erythromycin; a second-generation cephalosporin; and trimethoprim-sulfamethoxazole. OUTCOMES: In order of importance: efficacy, side effects and cost. EVIDENCE: A MEDLINE search of articles published between January 1980 and December 1991. For clinical trial data, greatest emphasis was placed on randomized, double-blind studies using appropriate controls. VALUES: The Committee on AntimicrobialAgents of the Canadian Infectious Disease Society (CIDS) and two recognized experts (T.K.W. and O.D.R.) recommended antimicrobial regimens suitable for prophylaxis of infections in surgery. Whenever possible, recommendations were based on data from randomized controlled trials. BENEFITS, HARMS AND COSTS: Implementation of the guidelines is expected to reduce the incidence of postoperative infections, the inappropriate use of antibiotics and costs to hospitals. RECOMMENDATIONS: Antibiotic prophylaxis is recommended for operations with a high risk of postoperative wound infection or with a low risk of infection but significant consequences if infection occurs. These operations include clean-contaminated procedures and certain clean procedures. Drugs should be administered intravenously immediately before the operation. In colorectal operations oral administration also appears to be effective. A single dose is sufficient for most procedures. The regimen chosen depends on the pathogens usually associated with wound infection in a given operation, the serum half-life of the drugs, the antimicrobial susceptibility patterns in the local hospital and the cost of the drugs. VALIDATION: The guidelines were compared with others in standard textbooks of surgery and peer-reviewed articles. The guidelines were prepared and revised by the Committee on AntimicrobialAgents of the CIDS. They were then reviewed and revised further by the Council of the CIDS. SPONSOR: The CIDS was solely responsible for developing, funding and endorsing these guidelines.
The use of antimicrobialagents in humans and food-producing animals has important consequences for human and animal health, as it can lead to the development of resistant bacteria (pathogens and/or commensals with resistance genes). Moreover, resistant bacteria in animals can be transferred to people--usually through the consumption of food, but also through direct contact with food-producing animals or through environmental spread. Ultimately, this can result in human infections with bacteria that are resistant to antimicrobialagents and that can therefore be difficult or impossible to cure. Of special concern is resistance to antimicrobialagents classified by the World Health Organization (WHO) as critically important for human medicine, such as fluoroquinolones, third- and fourth-generation cephalosporins, and macrolides. WHO encourages the agricultural, food, veterinary and health sectors to work together to eliminate the burden of antimicrobial resistance arising from the use of antimicrobialagents in food-producing animals. Joint efforts should be made to reduce the inappropriate use of antimicrobialagents (e.g. the use of antimicrobials as growth promoters) and limit the spread of bacteria resistant to antimicrobialagents. WHO will continueto address this issue in conjunction with the Food and Agriculture Organization of the United Nations, the World Organisation for Animal Health, the animal health/production industry and other important stakeholders. It will also continue to enhance the capacity of its Member States (through training courses and sentinel studies), particularly developing countries, to conduct integrated surveillance of antimicrobial use and resistance, to carry out risk assessments to support the selection of risk management options and to implement strategies for the containment of antimicrobial resistance. PMID:22849282
Purpose Even though sediments may represent a reservoir for antimicrobialagents, little is known about the persistence of these molecules\\u000a over time or their accumulation. In this study, six antimicrobialagents, oxolinic acid, flumequine, nalidixic acid, norfloxacin,\\u000a sulphamethoxazole and trimethoprim, were investigated in a sediment core from the Seine River. This work aimed to (1) measure\\u000a antimicrobialagent contamination levels in
Fatima Tamtam; Barbara Le Bot; Tuc Dinh; Sophie Mompelat; Joelle Eurin; Marc Chevreuil; Philippe Bonté; Jean-Marie Mouchel; Sophie Ayrault
Treatment of otorrhea has been described in the literature since 1500 BC. A multitude of therapeutic options have been described, including the use of astringents, antiseptics, alcohol, benzoin and various powders. Since the middle of the 20th century, antibiotic usage has been promoted as the most effective means of therapy. Until recently none of the agents that were used was found to be safe for middle ear use. Since 1990 there have been publications describing the safety and efficacy of fluoroquinolone drops for acute and chronic otorrhea. This article details the transition from treatment of otorrhea with nonspecific means to an era of antimicrobial therapy based on sound scientific evidence. PMID:11176585
The evolution of antimicrobial resistance in Salmonella isolates causing traveler's diarrhea (TD) and their mechanisms of resistance to several antimicrobialagents were analyzed. From 1995 to 2002, a total of 62 Salmonella strains were isolated from stools of patients with TD. The antimicrobial susceptibility to 12 antibiotics was determined, and the molecular mechanisms of resistance to several of them were
Roberto Cabrera; Joaquő ´ m Ruiz; Francesc Marco; Ines Oliveira; Margarita Arroyo; A. Aladuena; M. A. Usera; M. T. Jimenez De Anta; J. Gascon; J. Vila
Antibiotic interactions with cells, including polymorphonuclear neutrophils, may influence therapeutic outcomes. Selected microbes (e.g., Legionella pneumophila) may survive ingestion by polymorphonuclear neutrophils and are thus protected from the action of antimicrobialagents that remain extracellular. Antibiotics that penetrate the cell can kill these microbes. Certain antibiotics are concentrated inside phagocytes, and when the phagocyte migrates toward the site of infection, the antibiotic-loaded cell carries the active agent to the infecting microbes. Active antibiotic may be released when the short-lived phagocyte dies. Even microbes considered to be extracellular pathogens, such as pneumococci, may survive high concentrations of antibiotic by entering cells. Antibiotics that penetrate and are active in cells may aid in enhancing therapeutic outcomes and in eliminating the carrier state for some pathogens. PMID:16305282
Methanol extract of three Nigerian medicinal plants were screened for antimicrobial activity using modified Kirby-Bauer disc diffusion and agar dilution techniques to determine the diameters of zone of inhibition and minimum inhibitory concentrations (MIC) of the extracts respectively. The extract of each of the plants were tested against five clinical bacterial isolates comprising of two Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) and three Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumonia) organisms. All the extracts exhibited moderate to high level of antimicrobial activities against these microorganisms. Phytochemical screening of powdered plant material revealed the presence of some secondary metabolites such as alkaloids, saponins, tannins, anthraquinones and flavonoids. These Nigerian medicinal plants could be developed into cheap, safe and culturally acceptable standardized herbal products and may serve as a source of new molecules for broad-spectrum antimicrobialagents. PMID:22654215
Small antimicrobial peptides are excellent candidates for inclusion in self-processing proteins that could be used to confer pathogen resistance in transgenic plants. Antimicrobial peptides as small as 22 amino acids in length have been designed to incorporate the residual amino acids left from protein processing by the tobacco etch virus'(TEVs') NIa protease. Also, by minimizing the length of these peptides and the number of highly hydrophobic residues, haemolytic activity was reduced without affecting the peptide's antimicrobial activity. PMID:10972721
Antimicrobialagents are the most valuable means available for treating bacterial infections. However, the administration of therapeutic doses of antimicrobialagents to patients is a leading cause of disturbance of the normal gastrointestinal microflora. This disturbance results in diminishing the natural defense mechanisms provided by the colonic microbial ecosystem, making the host vulnerable to infection by commensal microorganisms or nosocomial pathogens. In this minireview, the impacts of antimicrobials, individually and in combinations, on the human colonic microflora are discussed.
Rafii, Fatemeh; Sutherland, John B; Cerniglia, Carl E
The widespread detection of pharmaceutically active compounds, including many synthetic antimicrobialagents, in aquatic environments is raising public health concerns. As a result, there is growing interest in the development of innovative technologies to efficiently transform these compounds to non-toxic and pharmaceutically inactive byproducts. This work examines the photocatalytic degradation of sulfamethoxazole (SMX) and related sulfonamide antimicrobialagents in aqueous
Lanhua Hu; Phillip M. Flanders; Penney L. Miller; Timothy J. Strathmann
The use of antimicrobialagents in food animals has caused concern regarding the impact these uses have on human health. Use of antimicrobialagents in animals and humans results in the emergence and dissemina- tion of resistant bacteria. Resistant bacteria from food animals may be passed through the food chain to hu- mans resulting in resistant infections. Increasing resistance to
Alicia D. Anderson; Jennifer M. Nelson; Shannon Rossiter; Frederick J. Angulo
The in vitro susceptibility of 27 Campylobacter jejuni, 31 Campylobacter coli, and 30 Campylobacter fetus subsp. fetus strains to 12 antimicrobialagents was determined. Ciprofloxacin, a new quinoline derivative, was the most active agent tested. Antimicrobial susceptibility differed among the three species tested.
Fliegelman, R M; Petrak, R M; Goodman, L J; Segreti, J; Trenholme, G M; Kaplan, R L
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 antimicrobialagents. 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
Plantantimicrobials are not used as systemic antibiotics at present. The main reason for this is their low level of activity, especially against gram-negative bacteria. The reported MIC is often in the range of 100 to 1,000 ?g/ml, orders of magnitude higher than those of common broad-spectrum antibiotics from bacteria or fungi. Major plant pathogens belong to the gram-negative bacteria, which makes the low level of activity of plantantimicrobials against this group of microorganisms puzzling. Gram-negative bacteria have an effective permeability barrier, comprised of the outer membrane, which restricts the penetration of amphipathic compounds, and multidrug resistance pumps (MDRs), which extrude toxins across this barrier. It is possible that the apparent ineffectiveness of plantantimicrobials is largely due to the permeability barrier. We tested this hypothesis in the present study by applying a combination of MDR mutants and MDR inhibitors. A panel of plantantimicrobials was tested by using a set of bacteria representing the main groups of plant pathogens. The human pathogens Pseudomonas aeruginosa, Escherichia coli, and Salmonella enterica serovar Typhimurium were also tested. The results show that the activities of the majority of plantantimicrobials were considerably greater against the gram-positive bacteria Staphylococcus aureus and Bacillus megaterium and that disabling of the MDRs in gram-negative species leads to a striking increase in antimicrobial activity. Thus, the activity of rhein, the principal antimicrobial from rhubarb, was potentiated 100- to 2,000-fold (depending on the bacterial species) by disabling the MDRs. Comparable potentiation of activity was observed with plumbagin, resveratrol, gossypol, coumestrol, and berberine. Direct measurement of the uptake of berberine, a model plantantimicrobial, confirmed that disabling of the MDRs strongly increases the level of penetration of berberine into the cells of gram-negative bacteria. These results suggest that plants might have developed means of delivering their antimicrobials into bacterial cells. These findings also suggest that plantantimicrobials might be developed into effective, broad-spectrum antibiotics in combination with inhibitors of MDRs.
Tegos, George; Stermitz, Frank R.; Lomovskaya, Olga; Lewis, Kim
Background In Cameroon, the use of edible plants is an integral part of dietary behavior. However, evidence of the antimicrobial as well as the cytotoxic effects of many of them has not been investigated. In the present study, aqueous and methanol extracts from barks, seeds, leaves and roots of three Cameroonian edible plants namely Garcina lucida, Fagara heitzii and Hymenocardia lyrata were evaluated for their cytotoxic and antimicrobial activities. Methods Antibacterial and antifungal activities were assessed by the broth micro-dilution method meanwhile the cytotoxicity was performed using sulphorhodamine B assay (SRB) against the human leukemia THP-1, the alveolar epithelial A549, prostate cancer PC-3, breast adenocarcinoma MCF-7 and cervical cancer HeLa cell lines. Results The minimum inhibitory concentration (MIC) values of the seven tested extracts ranged from 62.5 ?g/ml to 1000 ?g/ml. The methanol (MeOH) extract from the roots of H. lyrata showed the highest antibacterial activity against Gram-positive bacteria S. aureus and S. epidermitis. The best antifungal activity was obtained with the MeOH extract from the leaves of G. lucida against C. tropicalis (MIC value of 62.5 ?g/ml). The in vitro antiproliferative activity revealed that, extract from the bark of F. heitzii and extract from H. lyrata roots had significant cytotoxic activity on THP-1 (IC50 8.4 ?g/ml) and PC-3 (IC50 9.5 ?g/ml) respectively. Conclusion Our findings suggest that Cameroonian spices herein studied could be potentially useful for the development of therapeutic agents against bacterial infections as well as for prostate and leukemia cancer.
The diagnosis of invasive aspergillosis which is a serious infection of immunocompromized patients, depends on the detection of Aspergillus galactomannan antigen in the serum by enzyme immunoassay (EIA) in routine laboratories. However, it has been previously reported that false positive results in Aspergillus galactomannan test may be obtained in the sera of patients sera receiving piperacillin-tazobactam (PIP-TAZ). The aim of this study was to investigate the presence and levels of Aspergillus galactomannan antigen in the content of PIP-TAZ and some other antimicrobialagents that are often used for the treatment of infections in immunocompromised patients. The level of galactomannan antigen was determined for PIP-TAZ, ampicillin-sulbactam, ampicillin, penicillin G, ceftriaxone, cefepime, imipenem, clarithromycin, ciprofloxacin, vancomycin, gentamicin, trimethoprim-sulfamethoxazole, ornidazole, fluconazole and amphotericin B, by a commercial EIA (Platelia Aspergillus EIA, Bio-Rad, France) kit. Galactomannan index (GI) was estimated with the ratio of absorbance values of antimicrobials to cut-off value and evaluated as positive when GI was found >0.5. Amongst the 15 antibiotics studied, the only positive result was detected for ampicillin with the highest index value (GI = 0.540), followed by PIP-TAZ with a relatively high value (GI = 0.235) even though it was not in the range of positivity. GI values have ranged from 0.011 to 0.188 for the other antibiotics. In conclusion, the use of especially ampicillin (and probably PIP-TAZ) therapy should be questioned in patients whose sera are being tested for Aspergillus galactomannan antigen by EIA in order to evaluate the positive results in terms of false positivities due to cross reactivity. PMID:18173075
Pseudomonas aeruginosa is an opportunistic microorganism that is frequently the cause of nosocomial infections. Multiple mechanisms are involved in its natural and acquired resistance to many of the antimicrobialagents commonly used in clinical practice. The objective of this study was to assess the susceptibility and resistance patterns of P. aeruginosa strains isolated in Hospital Reina Sofia between 2000 and 2005, as well as to analyze the differences between intrahospital and extrahospital isolates in 2005 and to compare the results with those obtained in other studies. A total of 3,019 strains of P. aeruginosa from different hospitals and nonhospital settings were evaluated, taking into consideration their degree of sensitivity to different antibiotics. The MICs were determined by means of the Wider I automated system (Soria Melguizo), taking into consideration the criteria of susceptibility and resistance recommended by MENSURA. Results of the analysis showed that P. aeruginosa maintained similar levels of antimicrobial susceptibility during the period 2000-2005, with increased susceptibility to amikacin, gentamicin and tobramycin. There were also important differences in the degree of susceptibility between intrahospital and extrahospital strains, except for imipenem and fosfomycin. The intrahospital difference in susceptibility was also evaluated, emphasizing the importance of periodically studying susceptibility and resistance patterns of P. aeruginosa in each setting in order to evaluate different therapeutic guidelines, as it is not always advisable to extrapolate data from different regions. These differences can be explained by the different use of antibiotics in each center and the geographic variations of the resistance mechanisms of P. aeruginosa. PMID:17893761
Gamero Delgado, M C; García-Mayorgas, A D; Rodríguez, F; Ibarra, A; Casal, M
The role of uncondensed 1,2,4-triazine derivatives and the related compounds as biocidal plant protection agents such as herbicides, bactericidal, fungicidal, antimicrobial, protozacides, anticoccidal, parasiticides, insecticides, acaricdes and pesticides, is reviewed. PMID:11265582
The medicinal plant, Coccinia cordifolia L. was analyzed for its chemical composition. The antimicrobial activities of the methanol, water, ethanol and ethyl acetate extracts of Coccinia cordifolia L. plant were evaluated against some Gram positive bacteria (Sarcina lutea, Bacillus subtilis and Staphylococcus aureus), Gram negative bacteria (Salmonella typhi, Shigella dysenteriae and Escherichia coli) and fungi (Candida albicans, Aspergillus niger and Penicillium notatum). Chemical analysis showed that the plant is rich in nutrients, especially antioxidant compounds such as total phenol, vitamin C and ?-carotene. Phytochemical screening showed that the methanolic extract contains the bioactive constituents such as tannins, saponins, phenols, flavonoids and terpenoids. In the methanolic extract of the plant, promising antimicrobial potential was observed against the tested microorganism. Methanolic extract showed highest activity against Shigella dysenteriae, Escherichia coli, Staphylococcus aureus, and Candida albicans compared to the other extracts. Water extract showed less antimicrobial activity as compared to other extractants. PMID:23009991
Khatun, Shahanaz; Pervin, Farzana; Karim, Mohammad Rezaul; Ashraduzzaman, Mohammad; Rosma, Ahmad
Antimicrobial resistance is a growing area of concern in both human and veterinary medicine. This review presents an overview of the use of antimicrobialagents in animals for therapeutic, metaphylactic, prophylactic and growth promotion purposes. In addition, factors favouring resistance development and transfer of resistance genes between different bacteria, as well as transfer of resistant bacteria between different hosts, are
Animal models of infection should be considered as tools that may be used for many different purposes: investigation of the physiopathology and natural history of infection on one hand, evaluation of the toxicity, pharmacokinetics and activity of antimicrobials on the other hand. Many review articles on the use of animal models of infection for the evaluation of antimicrobialagents have
As considerable variation in the antimicrobial susceptibility of Haemophilus influenzae has been reported, the effects of various test media on the susceptibility of H. influenzae were studied. MICs were determined by three laboratories for 21 antimicrobialagents against a panel of 100 selected isolates. Testing was performed using a reference NCCLS frozen broth microdilution method with Haemophilus test medium (HTM)
Michael R. Jacobs; Saralee Bajaksouzian; Anne Windau; Peter C. Appelbaum; Gengrong Lin; David Felmingham; Christine Dencer; Laura Koeth; Mendel E. Singer; Caryn E. Good
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.
Leonard, Brian C.; Affolter, Verena K.; Bevins, Charles L.
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 antimicrobialagents used for growth promotion as part of the Danish program of monitoring for antimicrobial resistance. The four antimicrobials were avilamycin, erythromycin, vancomycin, and
FRANK MŘLLER AARESTRUP; ANNE METTE SEYFARTH; HANNE-DORTHE EMBORG; KARL PEDERSEN; R. S. Hendriksen; F. Bager
The susceptibilities of 265 strains of Corynebacterium species and other non-spore-forming gram-positive bacilli to 18 antimicrobialagents were tested. Most strains were susceptible to vancomycin, doxycycline, and fusidic acid. Corynebacterium jeikeium and Corynebacterium urealyticum were the most resistant organisms tested. Resistance to beta-lactams, clindamycin, erythromycin, azythromycin, ciprofloxacin and gentamicin was common among strains of Corynebacterium xerosis and Corynebacterium minutissimum. Ampicillin resistance among Listeria monocytogenes was more prevalent than previously reported. Optochin, fosfomycin, and nitrofurantoin showed very little activity against most organisms tested, but the use of nitrofurantoin as a selective agent in culture medium may prevent the recovery of some isolates. Except for the unvarying activity of vancomycin against Corynebacterium species, the antimicrobial susceptibilities of the latter to other antibiotics are usually unpredictable, such that susceptibility tests are necessary for selecting the best antimicrobial treatment. PMID:7695308
The primary theme emerging from molecular genetic work conducted with Mycobacterium tuberculosis and several other mycobacterial species is that resistance is commonly associated with simple nucleotide alterations in target chromosomal genes rather than with acquisition of new genetic elements encoding antibiotic-altering enzymes. Mutations in an 81-bp region of the gene (rpoB) encoding the beta subunit of RNA polymerase account for rifampin resistance in 96% of M. tuberculosis and many Mycobacterium leprae isolates. Streptomycin resistance in about one-half of M. tuberculosis isolates is associated with missense mutations in the rpsL gene coding for ribosomal protein S12 or nucleotide substitutions in the 16S rRNA gene (rrs). Mutations in the katG gene resulting in catalase-peroxidase amino acid alterations nad nucleotide substitutions in the presumed regulatory region of the inhA locus are repeatedly associated with isoniazid-resistant M. tuberculosis isolates. A majority of fluoroquinolone-resistant M. tuberculosis isolates have amino acid substitutions in a region of the DNA gyrase A subunit homologous to a conserved fluoroquinolone resistance-determining region. Multidrug-resistant isolates of M. tuberculosis arise as a consequence of sequential accumulation of mutations conferring resistance to single therapeutic agents. Molecular strategies show considerable promise for rapid detection of mutations associated with antimicrobial resistance. These approaches are now amenable to utilization in an appropriately equipped clinical microbiology laboratory.
The invention relates to novel glycolic acid fatty ester derivatives which are useful as yarn lubricants and antimicrobialagents. Fiber lubricants, sometimes referred to as spinning oils or coning oils, are applied to textile fibers to facilitate handlin...
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
Antimicrobialagents are used in food animals for therapy and prophylaxis of bacterial infections and in feed to promote growth. The use of antimicrobialagents for food animals may cause problems in the therapy of infections by selecting for resistance among bacteria pathogenic for animals or humans. The emergence of resistant bacteria and resistance genes following the use of antimicrobial
Antimicrobialagents may interact with polymorphonuclear leukocytes and directly modify the leukocyte functions, or bacteria can be modified by the antimicrobialagents causing them to be treated differently by phagocytic cells. Brief exposure of bacteria to high levels of antimicrobials can affect their interaction with leukocytes. The susceptibility of Escherichia coli to phagocytosis and killing by human polymorphonuclear leukocytes in
P. Pérez; I. Herrera; M. Martín; P. Martínez; M. L. Gómez-Lus
Antibiotic resistance has become a problem since the discovery of antibiotics. Not long after\\u000a the introduction of penicillin, Staphylococcus aureus, which can be also\\u000a transmitted to humans via milk and milk products, began developing penicillin-resistant strains. Therefore,\\u000a one approach that has been used for the discovery of new antimicrobialagents from natural sources is based\\u000a on the evaluation of traditional plant
The aim of this study was to screen and evaluate the antimicrobial activity of indigenous Jordanian plant extracts, dissolved in dimethylsulfoxide, using the rapid XTT assay and viable count methods. XTT rapid assay was used for the initial screening of antimicrobial activity for the plant extracts. Antimicrobial activity of potentially active plant extracts was further assessed using the “viable plate
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
Veterinary antimicrobials have been detected in a number of environmental samples, including agricultural soils. In this study, the persistence and sorption of the sulfonamide sulfamethazine (SMZ) and sulfachloropyridine (SCP) in soil and their potential effects on soil microorganisms were investiga...
This study was conducted to describe the occurrence of acquired resistance to antimicrobials used for growth promotion among bacteria isolated from swine, cattle and poultry in Denmark. Resistance to structurally related therapeutic agents was also examined. Three categories of bacteria were tested: 1) indicator bacteria (Escherichia coli, Enterococcus faecalis, Enterococcus faecium), 2) zoonotic bacteria (Campylobacter, Salmonella, Yersinia enterocolitica), and 3) animal pathogens (E. coli, Staphylococcus aureus, coagulase-negative staphylococci (CNS), Staphylococcus hyicus, Actinobacillus pleuropneumoniae). All antimicrobials used as growth promoters in Denmark and some structurally related therapeutic agents (in brackets) were included: Avilamycin, avoparcin (vancomycin), bacitracin, carbadox, flavomycin, monensin, olaquindox, salinomycin, spiramycin (erythromycin, lincomycin), tylosin (erythromycin, lincomycin), and virginiamycin (pristinamycin). Bacterial species intrinsically resistant to an antimicrobial were not tested towards that antimicrobial. Breakpoints for growth promoters were established by population distribution of the bacteria tested. A total of 2,372 bacterial isolates collected during October 1995 to September 1996 were included in the study. Acquired resistance to all currently used growth promoting antimicrobials was found. A frequent occurrence of resistance were observed to avilamycin, avoparcin, bacitracin, flavomycin, spiramycin, tylosin and virginiamycin, whereas resistance to carbadox, monensin, olaquindox and salinomycin was less frequent. The occurrence of resistance varied by animal origin and bacterial species. The highest levels of resistance was observed among enterococci, whereas less resistance was observed among zoonotic bacteria and bacteria pathogenic to animals. The association between the occurrence of resistance and the consumption of the antimicrobial is discussed. The results show the present level of resistance to growth promoters in bacteria from food animals in Denmark. They will form the baseline for comparison with future prospective studies, thereby enabling the determination of trends over time. PMID:9725794
Aarestrup, F M; Bager, F; Jensen, N E; Madsen, M; Meyling, A; Wegener, H C
Problem statement: About 32 extracts from eight selected medicinal plants, n amely Pereskia bleo , Pereskia grandifolia , Curcuma aeruginosa Roxb., Curcuma zedoria , Curcuma mangga , Curcuma inodora aff. Blatter , Zingiber officinale var. officinale (jahe gajah) and Zingiber officinale var. rubrum (jahe emprit) used by Malaysia traditional health c are systems were screened for their antimicrobial activity against
Koshy Philip; Sri Nurestri; Abd Malek; Wirakarnain Sani; Sim Kae Shin; Saravana Kumar; Lee Guan Serm; Syarifah N. S. A. Rahman
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
To study the efficiency of antimicrobialagents in contaminated creams, a complete four-factor trial was performed with Oleocremor leniens, Oleocremor syndermani and Hydrocremor stearini. These creams were prepared with and without the addition of antimicrobialagents (parabene combination, potassium sorbate), contaminated with 5 genera of micro-organisms and bacteriologically examined immediately after preparation and after storage for 14 and 28 d, respectively. It was found that all four factors considered in this trial (type of cream, type of antimicrobialagent, genus of microorganism, time) are interdependent. The efficiency of the antimicrobialagents depends above all upon the type of cream (which acts on the availability of the antimicrobialagents) and upon the micro-organisms. The global recommendation of anti-microbialagents is unsuitable. The test organisms and the test methods as well as the evaluation of their results should be standardized. PMID:7433506
Objectives: Fifty isolates of Burkholderia pseudomallei and 15 isolates of Burkholderia mallei were tested for their susceptibilities to 35 antimicrobialagents, including agents not previously tested against these bacteria. Methods: MICs were determined by agar dilution in Mueller-Hinton medium. Results: Among the antibiotics tested, lower MICs were obtained with imipenem, ceftazidime, piperacil- lin, piperacillin\\/tazobactam, doxycycline and minocycline. Fluoroquinolones and aminoglycosides
F. M. Thibault; E. Hernandez; D. R. Vidal; M. Girardet; D. Cavallo
Plantantimicrobials are not used as systemic antibiotics at present. The main reason for this is their low level of activity, especially against gram-negative bacteria. The reported MIC is often in the range of 100 to 1,000 g\\/ml, orders of magnitude higher than those of common broad-spectrum antibiotics from bacteria or fungi. Major plant pathogens belong to the gram-negative bacteria,
George Tegos; Frank R. Stermitz; Olga Lomovskaya; Kim Lewis
The phenanthroindolizidine plant alkaloids pergularinine (PGL) and tylophorinidine (TPD) isolated from the Indian medicinal herb Pergularia pallida have been evaluated for their biological activity and assessed for the first time employing dihydrofolate reductase (DHFR) (5,6,7,8-THF: NADP(+) oxidoreductase, EC 220.127.116.11) as the probe in the present investigations. The enzyme is a key target in cancer chemotherapy and has been purified from Lactobacillus leichmannii. Cytotoxicity studies showed that both PGL and TPD are potently toxic and inhibited the growth of L. leichmannii cells (IC(50)=45 and 40 microM, respectively). Both the alkaloids significantly inhibited DHFR activity (IC(50)=40 and 32 microM for PGL and TPD, respectively). Alkaloid concentrations greater than 75-95 microM resulted in a complete loss of DHFR activity. Our results are suggestive of the alkaloids as potential antimicrobial and antitumour compounds. Alkaloid binding to DHFR is slow and reversible. Inhibition kinetics revealed K(i) values of 9x10(-6) M and 7x10(-6) M for PGL and TPD, respectively for the enzyme and inhibition in both the cases was a simple linear 'non-competitive' type. PMID:10699361
The susceptibilities of 265 strains of Corynebacterium species and other non-spore-forming gram-positive bacilli to 18 antimicrobialagents were tested. Most strains were susceptible to vancomycin, doxycycline, and fusidic acid. Corynebacterium jeikeium and Corynebacterium urealyticum were the most resistant organisms tested. Resistance to b-lactams, clindamycin, erythromycin, azythromycin, ciprofloxacin and gentamicin was common among strains of Corynebacterium xerosis and Corynebacterium minutissimum. Ampicillin
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 antimicrobialagents, 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
During a prospective study of indwelling vascular catheter-related infections, 134 isolates ofStaphylococcus epidermidis were grown from 700 catheter tips.In vitro antimicrobial susceptibility testing of these isolates to oxacillin, vancomycin and ofloxacin was performed using the standard broth microdilution technique. These results were compared to those for the same organisms grown in biofilm before the addition of antimicrobialagents. In 96-well
The susceptibility of 22 clinical isolates ofCampylobacter pylori to eight antimicrobialagents was studied under varying pH conditions. Macrolides (erythromycin, dirythromycin), clindamycin and to a lesser extent quinolones lost efficacy at lowered pH. The activity of ampicillin and metronidazole remained relatively stable throughout the pH range tested. The effect of pH an antimicrobial efficacy may warrant consideration when selecting an
M. L. Grayson; G. M. Eliopoulos; M. J. Ferraro; R. C. Moellering
A series of 2,4,6-trisubstituted [1,3,5]triazines were synthesized and evaluated for their antimicrobial activity against two representative Gram-positive, Gram-negative bacteria and two fungi. Biological data revealed that among all the compounds screened, compounds 3f, 3g, 3h, 3i, 3m, 3o and 3p found to have promising antimicrobial activity against all the selected pathogenic bacteria and fungi. Out of the synthesized compounds seven analogues have shown MIC in the range of 6.25-12.5 ?g/mL. These compounds were generally nontoxic and may prove useful as antimicrobialagents. PMID:22742908
Gavade, Sandip N; Markad, Vijay L; Kodam, Kisan M; Shingare, Murlidhar S; Mane, Dhananjay V
The present study was carried out to evaluate the occurrence of Salmonellae in broiler chicken carcasses and to determine the antimicrobial resistance profile of the isolated strains. Twenty-five out of the 260 broiler chicken carcasses samples (9.6%) were positive for Salmonella. S. Enteritidis was the most frequent serovar. Nineteen Salmonella isolates were tested for antimicrobial resistance, and the results indicated that 94.7% were resistant to at least one antimicrobialagent. Resistance to streptomycin (73.7%), nitrofurantoin (52.3%), tetracycline (31.6%), and nalidixic acid (21%) were the prevalent amongst Salmonella strains tested.
Duarte, Dalila Angelica Moliterno; Ribeiro, Aldemir Reginato; Vasconcelos, Ana Mercia Mendes; Santos, Sylnei Barros; Silva, Juliana Vital Domingos; de Andrade, Patricia Lucia Arruda; de Arruda Falcao, Lucia Sadae Pereira da Costa
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.
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.
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
Plants produce small cysteine-rich antimicrobial peptides as an innate defense against pathogens. Based on amino acid sequence homology, these peptides were classified mostly as ?-defensins, thionins, lipid transfer proteins, cyclotides, snakins and hevein-like. Although many antimicrobialplant peptides are now well characterized, much information is still missing or is unavailable to potential users. The compilation of such information in one centralized resource, such as a database would therefore facilitate the study of the potential these peptide structures represent, for example, as alternatives in response to increasing antibiotic resistance or for increasing plant resistance to pathogens by genetic engineering. To achieve this goal, we developed a new database, PhytAMP, which contains valuable information on antimicrobialplant peptides, including taxonomic, microbiological and physicochemical data. Information is very easy to extract from this database and allows rapid prediction of structure/function relationships and target organisms and hence better exploitation of plant peptide biological activities in both the pharmaceutical and agricultural sectors. PhytAMP may be accessed free of charge at http://phytamp.pfba-lab.org.
Hammami, Riadh; Ben Hamida, Jeannette; Vergoten, Gerard; Fliss, Ismail
This article is the second of a two-part series reviewing antimicrobialagents that are used by the dermatologist. In part I we reviewed ?-lactam antibiotics and related compounds. In this section we again emphasize some newer agents (macrolides, fluoroquinolones) as well as some of the more commonly employed older agents (rifamycins, tetracyclines, trimethoprim-sulfamethoxazole, and clindamycin). (J Am Acad Dermatol 1997;37:365-81.)Learning
Marcia E. Epstein; Maria Amodio-Groton; Neil S. Sadick
Thiourea and guanidine substructural units are of significant importance as the compounds containing these core units either in the open or the cyclic form are known to display an array of pharmacological properties. This brief review assimilates the literature on the medicinal significance of thiourea and guanidine derivatives with respect to antimalarial and antimicrobial activities. PMID:23895095
Proper documentation of new antimicrobial drugs for governmental registration authorities includes extensive pharmacokinetic studies. Pharmacokinetics represents the bridge between the in vitro and in vivo phases of drug development. Both healthy human volunteers and patients must be studied, the former during the initial stages of the pharmacokinetic studies. The documentation should give information on the following: absorption from the gastrointestinal
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.
Pratap, Gowd M. J. S; Manoj, Kumar M. G.; Sai, Shankar A. J.; Sujatha, B.; Sreedevi, E.
Nitric oxide (NO) is a short-lived, diatomic, lipophilic gas that plays an integral role in defending against pathogens. Among its many functions are involvement in immune cell signaling and in the biochemical reactions by which immune cells defend against bacteria, fungi, viruses and parasites. NO signaling directs a broad spectrum of processes, including the differentiation, proliferation, and apoptosis of immune cells. When secreted by activated immune cells, NO diffuses across cellular membranes and exacts nitrosative and oxidative damage on invading pathogens. These observations led to the development of NO delivery systems that can harness the antimicrobial properties of this evanescent gas. The innate microbicidal properties of NO, as well as the antimicrobial activity of the various NO delivery systems, are reviewed.
Schairer, David O.; Chouake, Jason S.; Nosanchuk, Joshua D.; Friedman, Adam J.
Plant extracts obtained fromFeronia limonia (leaves)Xanthium trumarum (flowering twigs) andGlossocardia bosvellia (leaves) were tested for their antimicrobial properties against certain bacterial species Feronia leaf extract was ineffective\\u000a onBacillus pumilus andX. campestris, Vibrio cholerae was found quite sensitive to this extract The extract ofX strumarium showed an abnormality withV cholerae, where the inhibition exceeded the control with established antibiotics Similarly,G bosvellia
Plant extracts obtained from Feronia limonia (leaves) Xanthium strumarium (flowering twigs) and Glossocardia bosvellia (leaves) were tested for their antimicrobial properties against certain bacterial species. Feronia leaf extract was ineffective on Bacillus pumilus and X. campestris, Vibrio cholerae was found quite sensitive to this extract. The extract of X. strumarium showed an abnormality with V. cholerae, where the inhibition exceeded the control with established antibiotics. Similarly, G. bosvellia caused maximum inhibition in Bacillus mycoides. PMID:6667916
As functionalized chitosans hold great potential for the development of effective and broad-spectrum antibiotics, representative chitosan derivatives were tested for antimicrobial activity in neutral media: trimethyl chitosan (TMC), carboxy-methyl chitosan (CMC), and chitosan-thioglycolic acid (TGA; medium molecular weight: MMW-TGA; low molecular weight: LMW-TGA). Colony forming assays indicated that LMW-TGA displayed superior antimicrobial activity over the other derivatives tested: a 30 min incubation killed 100% Streptococcus sobrinus (Gram-positive bacteria) and reduced colony counts by 99.99% in Neisseria subflava (Gram-negative bacteria) and 99.97% in Candida albicans (fungi). To elucidate LMW-TGA effects at the cellular level, microscopic studies were performed. Use of fluorescein isothiocyanate (FITC)-labeled chitosan derivates in confocal microscopy showed that LMW-TGA attaches to microbial cell walls, while transmission electron microscopy indicated that this derivative severely affects cell wall integrity and intracellular ultrastructure in all species tested. We therefore propose LMW-TGA as a promising and effective broad-band antimicrobial compound. PMID:23470196
Geisberger, Georg; Gyenge, Emina Besic; Hinger, Doris; Käch, Andres; Maake, Caroline; Patzke, Greta R
Protein C inhibitor (PCI) is a heparin-binding serine proteinase inhibitor belonging to the family of serpin proteins. Here we describe that PCI exerts broad antimicrobial activity against bacterial pathogens. This ability is mediated by the interaction of PCI with lipid membranes, which subsequently leads to their permeabilization. As shown by negative staining electron microscopy, treatment of Escherichia coli or Streptococcus pyogenes bacteria with PCI triggers membrane disruption followed by the efflux of bacterial cytosolic contents and bacterial killing. The antimicrobial activity of PCI is located to the heparin-binding site of the protein and a peptide spanning this region was found to mimic the antimicrobial activity of PCI, without causing lysis or membrane destruction of eukaryotic cells. Finally, we show that platelets can assemble PCI on their surface upon activation. As platelets are recruited to the site of a bacterial infection, these results may explain our finding that PCI levels are increased in tissue biopsies from patients suffering from necrotizing fasciitis caused by S. pyogenes. Taken together, our data describe a new function for PCI in innate immunity. PMID:20019810
Malmström, Erik; Mörgelin, Matthias; Malmsten, Martin; Johansson, Linda; Norrby-Teglund, Anna; Shannon, Oonagh; Schmidtchen, Artur; Meijers, Joost C M; Herwald, Heiko
The occurrence of resistance patterns among wastewater fecal coliforms was determined in the study. Susceptibility of the isolates was tested against 19 antimicrobialagents: aminoglycosides, aztreonam, carbapenems, cephalosporines, beta-lactam/beta-lactamase inhibitors, penicillines, tetracycline, trimethoprim/sulfamethoxazole, and fluoroquinolones. Additionally the removal of resistant isolates was evaluated in the laboratory-scale wastewater treatment model plant (M-WWTP), continuously supplied with the wastewater obtained from the full-scale WWTP. Number of fecal coliforms in raw (after mechanical treatment) and treated wastewater, as well as in aerobic chamber effluent was determined using selective medium. The selected strains were identified and examined for antibiotic resistance using Phoenix Automated Microbiology System (BD Biosciences, USA). The strains were identified as Escherichia coli (n=222), Klebsiella pneumoniae ssp. ozaenae (n=9), and Pantoea agglomerans (n=1). The isolate of P. agglomerans as well as 48% of E. coli isolates were sensitive to all antimicrobials tested. The most frequent resistance patterns were found for ampicillin: 100% of K. pneumoniae ssp. ozaenae and 41% of E. coli isolates. Among E. coli isolates 12% was regarded as multiple antimicrobial resistant (MAR). In the studied M-WWTP, the applied activated sludge processes reduced considerably the number of fecal coliforms, but increased the ratio of antimicrobial-resistant E. coli isolates to sensitive ones, especially among strains with MAR patterns. PMID:20351416
Luczkiewicz, A; Fudala-Ksiazek, S; Jankowska, K; Quant, B; Ola?czuk-Neyman, K
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
A study assessed the effectiveness of a microcomputer-assisted instructional program using graphics, color, and text in simulations to enhance pharmacy students' knowledge of microbiology and antimicrobialagents. Results indicated high short- and long-term retention of information presented and higher levels of knowledge and comprehension among…
Synopsis Recent work on the microbiological activity, chemistry and safety of the antimicrobialagent Bronopol is reported. Methods for the estimation of Bronopol are described, and the nature of its decomposition products is discussed. Animal metabolism and toxicology results are reported, together with animal and human studies on irritancy and sensitisation. The performance of Bronopol in a number of experimental
The thiazole and imidazole nucleus, as well as carbohydrates are important classes of compounds found in many natural and synthetic products with a wide range of biological activities. Due to the importance of these classes of compounds as antimicrobialagents, the present article reports the synthesis of a new series of nine compounds based on the coupling of 2-mercaptobenzothiazole and
Mauro V. De Almeida; Sílvia H. Cardoso; Joăo V. De Assis; Marcus V. N. De Souza
Pasteurella multocida causes a wide variety of infections and is the most common localized soft tissue infection after animal bite injuries. Penicillin or amoxicillin has been considered agent of choice for therapy. Reported ?-lactamase production by some isolates, the therapeutic dilemma of the penicillin allergic patient, and the polymicrobial nature of some infections led to this study of alternate antimicrobial
Numerous studies have contributed to the development of natural and synthetic antimicrobial peptides as a prospective source of antibiotic agents. Based on the concept that cationic charge, bulk, and lipophilicity are major factors determining antibacterial activity in these peptides, we designed and screened several combinatorial libraries based on 1,3,5-triazine as a template. A set of compounds were identified to show
Chunhui Zhou; Jaeki Min; Zhigang Liu; Anne Young; Heather Deshazer; Tian Gao; Young-Tae Chang; Neville R. Kallenbach
The activity of serial concentrations of different antimicrobialagents on the multiplication of Legionella pneumophila within human monocyte-derived macrophages was studied. The results led to the definition of a minimal extracellular concentration inhibiting intracellular multiplication (MIEC). According to the MIECs, the antimicrobialagents tested were classified in three groups: very active (MIEC less than or equal to 0.06 microgram/ml), such as erythromycin, rifampin, and pefloxacin; active (1 microgram/ml greater than or equal to MIEC greater than or equal to 0.1 microgram/ml), such as sulfamethoxazole-trimethoprim or doxycycline; and ineffective, such as cefoxitin, which was not active within macrophages at as high as 64 micrograms/ml despite a low MIC (0.2 microgram/ml) on bacterial charcoal-yeast extract agar. The activity of netilmicin was difficult to assess because of its effect on extracellular legionellae. Combinations of erythromycin with rifampin and pefloxacin with erythromycin, rifampin, doxycycline, or netilmicin showed an additive effect and no antagonism. These results obtained in a cellular model are in agreement with the efficacy of antimicrobialagents in experimental infections and in Legionnaires disease. They sustain clinical interest in the new quinolones, such as pefloxacin, and in combinations of antimicrobialagents for the treatment of Legionnaires disease.
The incidence of Salmonella in 60 samples of poultry products of national origin available for consumers obtained from two local butcher shops and one canteen of the city of Porto and the susceptibility to antimicrobialagents allowed for human or animal therapy were evaluated. The results show that poultry samples are frequently contaminated with Salmonella (60%), belonging to 10 different
Currently available therapeutic options for non-insulin-dependent diabetes mellitus, such as dietary modification, oral hypoglycemics, and insulin, have limitations of their own. Many natural products and herbal medicines have been recommended for the treatment of diabetes. The present paper reviews medicinal plants that have shown experimental or clinical antidiabetic activity and that have been used in traditional systems of medicine; the
Mankil Jung; Hyun Chul Lee; Yoon-Ho Kang; Eun Seok Kang; Sang Ki Kim
Many studies have demonstrated that sub-minimum inhibitory concentrations (sub-MICs) of antimicrobialagents can inhibit bacterial biofilm formation. However, the mechanisms by which antimicrobialagents at sub-MICs inhibit biofilm formation remain unclear. At present, most studies are focused on Gram-negative bacteria; however, the effects of sub-MICs of antimicrobialagents on Gram-positive bacteria may be more complex. Streptococcus mutans is a major cariogenic bacterium. In this study, the S. mutans growth curve as well as the expression of genes related to S. mutans biofilm formation were evaluated following treatment with 0.5× MIC of chlorhexidine (CHX), tea polyphenols and sodium fluoride (NaF), which are common anticaries agents. The BioFlux system was employed to generate a biofilm under a controlled flow. Morphological changes of the S. mutans biofilm were observed and analysed using field emission scanning electron microscopy and confocal laser scanning microscopy. The results indicated that these three common anticaries agents could significantly upregulate expression of the genes related to S. mutans biofilm formation, and S. mutans exhibited a dense biofilm with an extensive extracellular matrix following treatment with sub-MICs of NaF and CHX. These findings suggest that sub-MICs of anticaries agents favour S. mutans biofilm formation, which might encourage dental caries progression. PMID:22421330
Antibiotic resistance is an increasing public health concern around the world, and is recognized as one of the greatest threats facing humankind in the 21(st) century. Natural antimicrobial peptides (AMPs) are small cationic amphiphilic peptides found in virtually all living organisms, and play a key role in the defense against bacterial infections. Compared with conventional antibiotics, which target specific metabolic processes, AMPs are able to adopt globally amphipathic conformations, and kill bacteria through disruption of their membranes. As such, AMPs do not readily induce drug-resistance. However, AMPs are associated with intrinsic drawbacks such as low-to-moderate activity, susceptibility to enzymatic degradation, and inconvenience for optimization. Recently, we have developed a new class of peptidomimetics termed "AApeptides". Such peptide mimics are highly resistant to protease degradation and are straightforward for chemical diversification and development. Our current studies show that AApeptides with globally amphipathic structures can mimic the bactericidal mechanism of AMPs, and display potent and broad-spectrum activity against both Gram-positive and -negative multi-drug-resistant bacteria. In this review, we summarize our current findings of antimicrobial AApeptides, and discuss potential future directions on the development of more potent and specific analogues. PMID:23722277
Naturally occurring antimicrobial compounds could be applied as food preservatives to protect food quality and extend the shelf life of foods and beverages. These compounds are naturally produced and isolated from various sources, including plants, animals and microorganisms, in which they constitute part of host defense systems. Many naturally occurring compounds, such as nisin, plant essential oils, and natamycin, have been widely studied and are reported to be effective in their potential role as antimicrobialagents against spoilage and pathogenic microorganisms. Although some of these natural antimicrobials are commercially available and applied in food processing, their efficacy, consumer acceptance and regulation are not well defined. This manuscript reviews natural antimicrobial compounds with reference to their applications in food when applied individually or in combination with other hurdles. It also reviews the mechanism of action of selected natural antimicrobials, factors affecting their antimicrobial activities, and future prospects for use of natural antimicrobials in the food industry. PMID:22385168
The antimicrobials crisis is a ticking time bomb which could lead to millions of people dying from untreatable infections. With the worsening trends of antimicrobial resistance, we are heading towards a pre-antibiotic era. Thus, there is a need for newer and more powerful antibiotic agents. The search for new antibiotic compounds originating from natural resources is a promising research area. Animals living in germ-infested environments are a potent source of antimicrobials. Under polluted milieus, organisms such as cockroaches encounter different types of bacteria, including superbugs. Such creatures survive the onslaught of superbugs and are able to ward off disease by producing antimicrobial substances which show potent activity in the nervous system. We hope that the discovery of antimicrobial activity in the cockroach brain will stimulate research in finding antimicrobials from unusual sources, and has potential for the development of novel antibiotics. Nevertheless, intensive research in the next few years will be required to approach or realize these expectations. PMID:23265422
Lee, Simon; Siddiqui, Ruqaiyyah; Khan, Naveed Ahmed
Current drug treatment of Clostridium difficile infection (CDI) focuses on metronidazole and vancomycin. Early studies showed equivalence, but more recent reports indicate that oral vancomycin is preferred for serious CDI. Recent work has demonstrated a need for new drugs due to challenges with the NAP-1 strain, which appears to cause more refractory disease that is more likely to relapse. These two distinctive facets of treatment are the most challenging. This review discusses new agents in development: antibiotics, probiotics, immune response products, and agents to bind C. difficile toxins. None are likely to be more effective than oral vancomycin for acute infection. However, several may be as effective, without causing relapse or promoting unnecessary antibiotic use for multiple conditions. The greatest promise is with agents used to interrupt relapses. In this category the leading new agents appear to be antibiotics (rifaximin, nitazoxanide, difimicin, ramoplanin), toxin-binding agents (tolevamer), probiotics (Saccharomyces -boulardii and Lactobacillus ramosus), and immune agents (toxoid vaccine and hyperimmune globulin). The drugs that appear most promising based on recent trials are rifaximin, tolevamer, and difimicin, which appear promising for reducing relapses. PMID:19094821
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.
The alarms that have sounded in the last two decades of the 20(th) century in the feld of antimicrobial resistance in livestock farming have led to the development of various measures that have substantially improved the use of antimicrobialagents in veterinary medicine. These measures mainly involve the implementation of new pharmaceutical legislation and the hygiene package provisions. Even though awareness of the regulations is high, surveillance systems have been implemented and the promotion of appropriate use has begun to show results, it is necessary to maintain these measures while promoting alternatives to the use of antimicrobials. In particular, alternatives are needed for those agents used for prevention of bacterial diseases, either specifically, through vaccination and improvement of biosafety (use of insecticides, disinfectants and insect repellents), or generally by improving farm facilities and animal welfare. All of these alternatives would reduce the need to use antimicrobialagents in animals. These actions should be complemented by training for all those players involved (veterinarians, farmers, the pharmaceutical industry, veterinary medicines suppliers and food retailers), and by establishing more effective cooperation between human and veterinary medicine. PMID:21458700
Rodríguez, Lucas Domínguez; Romo, Miguel Angel Moreno; Calonge, M Concepción Porrero; Peńa, Sonia Téllez
Bacteria grown in biofilms are less susceptible to antimicrobialagents than planktonic bacteria. One of the most common biofilms in humans is dental plaque. To investigate the antimicrobial activity against dental bacteria grown in biofilms, biofilms were generated with Streptococcus sanguis on hydroxyapatite disks to mimic the tooth surface. After 48 h of aerobic incubation at 37 degrees C in a continuous flow culture, a biofilm consisting of Streptococcus sanguis became visible on the surface of the disks. The disks were removed from the growth chamber and placed in different vessels containing either chlorhexidine digluconate (CAS 55-56-1, 0.1% or 1.0%), polyvinylpyrrolidone iodine (1.5% or 7.5%), or octenidine dihydrochloride (CAS 70775-75-6, 0.05% or 0.1%) for 5 or 30 min. In addition, the antiseptics were applied to the bacterial suspension in the growth chamber. A significant difference was observed in the antimicrobial activity against bacteria in the suspension liquid compared to the bacteria grown in biofilms. The best reduction factors were obtained with chlorhexidine (1.0%, 30 min) for either sessile (3.97 Ig) or planktonic bacteria (> or = 5.58 Ig). Clear relationships between the doses and times of action were found for the assessed agents. Therefore, the authors conclude that the present in vitro assay is a quick and cost-effective model to screen the activity of antimicrobialagents against bacteria grown in biofilms. PMID:12705173
Pitten, Frank-Albert; Doering, Sven; Kramer, Axel; Rosin, Michael
Currently available therapeutic options for non-insulin-dependent diabetes mellitus, such as dietary modification, oral hypoglycemics, and insulin, have limitations of their own. Many natural products and herbal medicines have been recommended for the treatment of diabetes. The present paper reviews medicinal plants that have shown experimental or clinical antidiabetic activity and that have been used in traditional systems of medicine; the review also covers natural products (active natural components and crude extracts) isolated from the medicinal plants and reported during 2001 to 2005. Many kinds of natural products, such as terpenoids, alkaloids, flavonoids, phenolics, and some others, have shown antidiabetic potential. Particularly, schulzeines A, B, and C, radicamines A and B, 2,5-imino-1,2,5-trideoxy-L-glucitol, beta-homofuconojirimycin, myrciacitrin IV, dehydrotrametenolic acid, corosolic acid (Glucosol), 4-(alpha-rhamnopyranosyl)ellagic acid, and 1,2,3,4,6-pentagalloylglucose have shown significant antidiabetic activities. Among active medicinal herbs, Momordica charantia L. (Cucurbitaceae), Pterocarpus marsupium Roxb. (Leguminoceae), and Trigonella foenum graecum L. (Leguminosae) have been reported as beneficial for treatment of type 2 diabetes. PMID:16719780
Jung, Mankil; Park, Moonsoo; Lee, Hyun Chul; Kang, Yoon-Ho; Kang, Eun Seok; Kim, Sang Ki
In this study an effective nanocomposite antimicrobialagent for wool fabric was introduced. The silver loaded nano TiO(2) as a nanocomposite was prepared through UV irradiation in an ultrasonic bath. The nanocomposite was stabilized on the wool fabric surface by using citric acid as a friendly cross-linking agent. The treated wool fabrics indicated an antimicrobial activity against both Staphylococcus aureus and Escherichia coli bacteria. Increasing the concentration of Ag/TiO(2) nanocomposite led to an improvement in antibacterial activities of the treated fabrics. Also increasing the amount of citric acid improved the adsorption of Ag/TiO(2) on the wool fabric surface leading to enhance antibacterial activity. The EDS spectrum, SEM images, and XRD patterns was studied to confirm the presence of existence of nanocomposite on the fabric surface. The role of both cross-linking agent and nanocomposite concentrations on the results was investigated using response surface methodology (RSM). PMID:21474327
Montazer, Majid; Behzadnia, Amir; Pakdel, Esfandiar; Rahimi, Mohammad Karim; Moghadam, Mohammad Bameni
Activities of conventional antifungal agents, fludioxonil, strobilurin and antimycin A, which target the oxidative and osmotic stress response systems, were elevated by coapplication of certain benzo analogs (aldehydes and acids). Fungal tolerance to 2,3-dihydroxybenzaldehyde or 2,3-dihydroxybenzoic acid was found to rely upon mitochondrial superoxide dismutase (SOD2) or glutathione reductase (GLR1), genes regulated by the HOG1 signaling pathway, respectively. Thus, certain benzo analogs can be effective at targeting cellular oxidative stress response systems. The ability of these compounds to chemosensitize fungi for improved control with conventional antifungal agents is discussed. PMID:18284447
Kim, Jong H; Mahoney, Noreen; Chan, Kathleen L; Molyneux, Russell J; May, Gregory S; Campbell, Bruce C
Antimicrobialagents used in antimicrobial products are classified into inorganic, organic, and natural organic compounds. Inorganic agents, such as Cu, Zn, and Ag compounds, are known to be relatively safe, and these agents are used in many kinds of products. Patients with metal allergy and infants should avoid coming in contact with products in which inorganic agents are used at
The free-living amoeba Balamuthia mandrillaris causes usually fatal encephalitis in humans and animals. Only limited studies have investigated the efficacy of antimicrobialagents 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
The effects of several chemotherapeutic agents on the chemotaxis of human leukocytes were studied in an in vitro system using a Sykes-Moore chamber and a double-filter technique. Chemotactic factor was generated by the interaction of normal human serum and zymosan. At concentrations comparable to and below therapeutic blood levels, tetracycline HCI, erythromycin base and clindamycin HCI were all inhibitory, causing
Nancy B. Esterly; Nancy L. Furey; Lillian E. Flanagan
The measurement of gas produced as a fermentation end product in vitro was correlated with absorbance as a measure of bacterial growth and was used as a rapid screening procedure to test the antimicrobial activity of certain essential oil and tannin secondary plant metabolites on gastrointestinal microorganisms from chickens. The assay was optimised using Clostridium perfringens and Lactobacillus fermentum, and
S. Shanmugavelu; G. Ruzickova; J. Zrustova; J. D. Brooker
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-microbialagents. 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
Adverse drug reactions are a major cause of hospital admission and in-hospital morbidity. Antimicrobialagents are one of the most commonly prescribed groups of drugs leading to adverse drug reactions. But, limited data is available from hospital settings in our country. Hence, it is important to understand the characteristics of adverse reactions associated with their use. This study was planned to detect the adverse drug reactions through spontaneous reporting system and analyse them using standard assessment scales. It is an observational, prospective study performed in patients attending outpatient department, in-patient department and casualty of tertiary care hospital from 1st June 2005 to 31st May 2009. Patients were examined for adverse drug reactions by spontaneous adverse drug reactions reporting system. Among 2639 total adverse drug reactions reported, 1315 (49.82%) were due to antimicrobialagents. The agents most frequently associated with adverse drug reactions were cotrimoxazole (19.54%), ampicillin (18.25%), rifampicin (6.6%) and azithromycin (5.3%). It is observed that commonly used drugs like antimicrobialagents were causing maximum adverse drug reactions. This study provides a database of adverse drug reactions due to common drugs, which will help clinicians for optimum and safe use of these drugs. PMID:23025221
Uchit, G P; Shrivastava, M P; Badar, V A; Navale, S B; Mayabhate, M M
There is a paucity of information regarding antimicrobialagents that are suitable to treat severe infections caused by multidrug-resistant Campylobacter spp. Our aim was to identify agents that are potentially effective against multiresistant Campylobacter strains. The in vitro activities of 20 antimicrobialagents against 238 Campylobacter strains were analyzed by determining MICs by the agar plate dilution method or the Etest. These strains were selected from 1,808 Campylobacter isolates collected from Finnish patients between 2003 and 2005 and screened for macrolide susceptibility by using the disk diffusion test. The 238 strains consisted of 183 strains with erythromycin inhibition zone diameters of < or =23 mm and 55 strains with inhibition zone diameters of >23 mm. Of the 238 Campylobacter strains, 19 were resistant to erythromycin by MIC determinations (MIC > or = 16 microg/ml). Given that the resistant strains were identified among the collection of 1,808 isolates, the frequency of erythromycin resistance was 1.1%. All erythromycin-resistant strains were multidrug resistant, with 18 (94.7%) of them being resistant to ciprofloxacin (MIC > or = 4 microg/ml). The percentages of resistance to tetracycline and amoxicillin-clavulanic acid (co-amoxiclav) were 73.7% and 31.6%, respectively. All macrolide-resistant strains were susceptible to imipenem, meropenem, and tigecycline. Ten (52.6%) multiresistant strains were identified as being Campylobacter jejuni strains, and 9 (47.4%) were identified as being C. coli strains. These data demonstrate that the incidence of macrolide resistance was low but that the macrolide-resistant Campylobacter strains were uniformly multidrug resistant. In addition to the carbapenems, tigecycline was also highly effective against these multidrug-resistant Campylobacter strains in vitro. Its efficacy for the treatment of human campylobacteriosis should be evaluated in clinical trials. PMID:20038624
There is a paucity of information regarding antimicrobialagents that are suitable to treat severe infections caused by multidrug-resistant Campylobacter spp. Our aim was to identify agents that are potentially effective against multiresistant Campylobacter strains. The in vitro activities of 20 antimicrobialagents against 238 Campylobacter strains were analyzed by determining MICs by the agar plate dilution method or the Etest. These strains were selected from 1,808 Campylobacter isolates collected from Finnish patients between 2003 and 2005 and screened for macrolide susceptibility by using the disk diffusion test. The 238 strains consisted of 183 strains with erythromycin inhibition zone diameters of ?23 mm and 55 strains with inhibition zone diameters of >23 mm. Of the 238 Campylobacter strains, 19 were resistant to erythromycin by MIC determinations (MIC ? 16 ?g/ml). Given that the resistant strains were identified among the collection of 1,808 isolates, the frequency of erythromycin resistance was 1.1%. All erythromycin-resistant strains were multidrug resistant, with 18 (94.7%) of them being resistant to ciprofloxacin (MIC ? 4 ?g/ml). The percentages of resistance to tetracycline and amoxicillin-clavulanic acid (co-amoxiclav) were 73.7% and 31.6%, respectively. All macrolide-resistant strains were susceptible to imipenem, meropenem, and tigecycline. Ten (52.6%) multiresistant strains were identified as being Campylobacter jejuni strains, and 9 (47.4%) were identified as being C. coli strains. These data demonstrate that the incidence of macrolide resistance was low but that the macrolide-resistant Campylobacter strains were uniformly multidrug resistant. In addition to the carbapenems, tigecycline was also highly effective against these multidrug-resistant Campylobacter strains in vitro. Its efficacy for the treatment of human campylobacteriosis should be evaluated in clinical trials.
Lehtopolku, Mirva; Nakari, Ulla-Maija; Kotilainen, Pirkko; Huovinen, Pentti; Siitonen, Anja; Hakanen, Antti J.
We describe the design and synthesis of a new series of non-natural short cationic lipopeptides (MW = 700) as antimicrobialagents. All of the synthesized lipopeptides were tested against a range of microbes such as Gram-positive, Gram-negative bacteria, fungi including methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE). By systematic study of design template, we found that three ornithine residues conjugated with myristic acid are minimum requirement for a compound to be an antimicrobialagent. The most potent lipopeptide LP16 possesses broad-spectrum antimicrobial activity and has MICs in the range of 1.5-6.25 ?g/mL against Escherichia coli, S. aureus, Pseudomonas aeruginosa, Bacillus subtilis, and MRSE. All lipopeptides showed high selectivity toward microbial strains as compared to human red blood cells (HC50 > 250 ?g/mL). Moreover, most potent lipopeptides (LP16 and LP23) did not induce drug resistance in S. aureus even after 15 rounds of passaging. In addition, a representative lipopeptide (LP16) showed tryptic stability for 24 h. These results suggest the potential of short cationic lipopeptides to boost the discovery of future antimicrobial therapeutics. PMID:23819506
Lohan, Sandeep; Cameotra, Swaranjit S; Bisht, Gopal S
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 antimicrobialagent 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
The antimicrobial activity of essential oils extracted from a variety of aromatic plants, often used in the Portuguese gastronomy was studied in vitro by the agar diffusion method. The essential oils of thyme, oregano, rosemary, verbena, basil, peppermint, pennyroyal and mint were tested against Gram-positive (Listeria monocytogenes, Clostridium perfringens, Bacillus cereus, Staphylococcus aureus, Enterococcus faecium, Enterococcus faecalis, and Staphylococcus epidermidis) and Gram-negative strains (Salmonella enterica, Escherichia coli, and Pseudomonas aeruginosa). For most essential oils examined, S. aureus, was the most susceptible bacteria, while P. aeruginosa showed, in general, least susceptibility. Among the eight essential oils evaluated, thyme, oregano and pennyroyal oils showed the greatest antimicrobial activity, followed by rosemary, peppermint and verbena, while basil and mint showed the weakest antimicrobial activity. Most of the essential oils considered in this study exhibited a significant inhibitory effect. Thyme oil showed a promising inhibitory activity even at low concentration, thus revealing its potential as a natural preservative in food products against several causal agents of foodborne diseases and food spoilage. In general, the results demonstrate that, besides flavoring the food, the use of aromatic herbs in gastronomy can also contribute to a bacteriostatic effect against pathogens. PMID:23444311
We demonstrated that borreliacidal activity caused by immune serum and complement can easily be differentiated by flow cytometry from killing activity caused by antimicrobialagents that are commonly used for the treatment of Lyme disease. Assay suspensions containing normal or immune serum were incubated with Borrelia burgdorferi in the presence or absence of ceftriaxone, doxycycline, penicillin, and phosphomycin for 2, 8, 16, and 24 h. Samples containing killing activity were identified by using flow cytometry and acridine orange. In 30 min, the effects of immune serum and complement were easily distinguished from the killing of spirochetes by antimicrobialagents by adding fluorescein isothiocyanate-conjugated goat anti-hamster immunoglobulin. This simple procedure greatly enhanced the usefulness of the borreliacidal assay by eliminating a major source of false-positive reactions.
Liu, Y F; Lim, L C; Schell, K; Lovrich, S D; Callister, S M; Schell, R F
The minimal inhibitory concentrations of 21 antimicrobialagents were determined by an agar dilution method against 68 strains of 18 Clostridium species isolated from caeca of pigs, cattle and poultry. Of the therapeutically used antibiotics, chloramphenicol was most active in vitro followed by penicillin G, the lincosamides and tetracycline. Penicillin-resistant Cl. butyricum strains produced a beta-lactamase. Avoparcin, carbadox, monensin, nitrovin and virginiamycin were the most effective of the growth promoting antimicrobialagents. Many clostridial species were naturally resistant to flavomycin and Cl. sporogenes was naturally resistant additionally to bacitracin, tiamulin, the lincosamides and virginiamycin component M. The macrolide, lincosamide and streptogramin resistant strains showed four different patterns of resistance to the antibiotics. One of these resistance patterns was the natural resistance of Cl. sporogenes to the lincosamides and virginiamycin component M which is a streptogramin group A antibiotic. PMID:6643330
We designed and prepared peptidotriazoles based on the antimicrobial peptide BP100 (LysLysLeuPheLysLysIleLeuLysTyrLeu-NH(2)) by introducing a triazole ring in the peptide backbone or onto the side chain of a selected residue. These compounds were screened for their in vitro growth inhibition of bacterial and fungal phytopathogens, and for their cytotoxic effects on eukaryotic cells and tobacco leaves. Their proteolytic susceptibility was also analyzed. The antibacterial activity and the hemolysis were influenced by the amino acid that was modified with the triazole as well as by the absence of presence of a substituent in this heterocyclic ring. We identified sequences active against the bacteria Xanthomonas axonopodis pv. vesicatoria, Erwinia amylovora, Pseudomonas syringae pv. syringae (MIC of 1.6-12.5 ?M), and against the fungi Fusarium oxysporum (MIC<6.2-12.5 ?M) with low hemolytic activity (0-23% at 50 ?M), high stability to protease digestion and no phytotoxicity. These peptidotriazoles constitute good candidates to design new antimicrobialagents. PMID:22198367
Researchers increasingly believe that microbial, molecular and synthetic biology techniques along with genetic engineering will facilitate the treatment of persistent infectious diseases. However, such therapy has been plagued by the emergence of antibiotic-resistant bacteria, resulting in significant obstacles to treatment. Phage therapy is one promising alternative to antibiotics, especially now that recent modifications to ubiquitous phages have made them more controllable. Additionally, convincing in vitro and in vivo studies of genetically modified lytic phages and engineered non-lytic phages have confirmed the advantages of novel, specific bactericidal agents over antibiotics in some cases. There is still a need for a better understanding of phage therapy, however, before it can be adopted widely. PMID:21689739
This article reviews the applications of nanotechnology in the fields of medical and life sciences. Nanoparticles have shown promising applications from diagnosis to treatment of various types of diseases including cancer. In this review, we discuss the applications of nanostructured materials such as nanoparticles, quantum dots, nanorods, nanowires, and carbon nanotubes in diagnostics, biomarkers, cell labeling, contrast agents for biological imaging, antimicrobialagents, drug delivery systems, and anticancer nanodrugs for treatment of cancer and other infectious diseases. The adverse affects of nanoparticles on human skin from daily use in cosmetics and general toxicology of nanoscale materials are also reviewed. PMID:21870454
Bacterial biofilms are resistant to conventional antimicrobialagents. Prior in vitro studies have shown that electrical current (EC) enhances the activities of aminoglycosides, quinolones, and oxytetracycline against Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus epidermidis, Escherichia coli, and Streptococcus gordonii. This phenomenon, known as the bioelectric effect, has been only partially defined. The purpose of this work was to study the in vitro bioelectric effect on the activities of 11 antimicrobialagents representing a variety of different classes against P. aeruginosa, methicillin-resistant Staphylococcus aureus (MRSA), and S. epidermidis. An eight-channel current generator/controller and eight chambers delivering a continuous flow of fresh medium with or without antimicrobialagents and/or EC to biofilm-coated coupons were used. No significant decreases in the numbers of log10 CFU/cm2 were seen after exposure to antimicrobialagents alone, with the exception of a 4.57-log-unit reduction for S. epidermidis and trimethoprim-sulfamethoxazole. We detected a statistically significant bioelectric effect when vancomycin plus 2,000 microamperes EC were used against MRSA biofilms (P = 0.04) and when daptomycin and erythromycin were used in combination with 200 or 2,000 microamperes EC against S. epidermidis biofilms (P = 0.02 and 0.0004, respectively). The results of these experiments indicate that the enhancement of the activity of antimicrobialagents against biofilm organisms by EC is not a generalizable phenomenon across microorganisms and antimicrobialagents.
del Pozo, Jose L.; Rouse, Mark S.; Mandrekar, Jayawant N.; Sampedro, Marta Fernandez; Steckelberg, James M.; Patel, Robin
Background Infectious diseases caused by multiresistant microbial strains are on the increase. Fighting these diseases with natural products may be more efficacious. The aim of this study was to investigate the in vitro antimicrobial activity of methanolic, ethylacetate (EtOAc) and hexanic fractions of five Cameroonian medicinal plants (Piptadeniastum africana, Cissus aralioides, Hileria latifolia, Phyllanthus muellerianus and Gladiolus gregasius) against 10 pathogenic microorganisms of the urogenital and gastrointestinal tracts. Methods The fractions were screened for their chemical composition and in vivo acute toxicity was carried out on the most active extracts in order to assess their inhibitory selectivity. The agar well-diffusion and the micro dilution methods were used for the determination of the inhibition diameters (ID) and Minimum inhibitory concentrations (MIC) respectively on 8 bacterial species including two Gram positive species (Staphylococcus aureus, Enterococcus faecalis), and six Gram negative (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, Shigella flexneri, Salmonella typhi) and two fungal isolates (Candida albicans, Candida krusei). The chemical composition was done according to Harbone (1976), the acute toxicity evaluation according to WHO protocol and the hepatic as well as serum parameters measured to assess liver and kidney functions. Results The chemical components of each plant's extract varied according to the solvent used, and they were found to contain alkaloids, flavonoids, polyphenols, triterpens, sterols, tannins, coumarins, glycosides, cardiac glycosides and reducing sugars. The methanolic and ethylacetate extracts of Phyllanthus muellerianus and Piptadeniastum africana presented the highest antimicrobial activities against all tested microorganisms with ID varying from 8 to 26 mm and MIC from 2.5 to 0.31 mg/ml. The in vivo acute toxicity study carried out on the methanolic extracts of Phyllanthus muellerianus and Piptadeniastrum africana indicated that these two plants were not toxic. At the dose of 4 g/kg body weight, kidney and liver function tests indicated that these two medicinal plants induced no adverse effect on these organs. Conclusion These results showed that, all these plant's extracts can be used as antimicrobial phytomedicines which can be therapeutically used against infections caused by multiresistant agents. Phyllanthus muellerianus, Piptadeniastum africana, antimicrobial, acute toxicity, kidney and liver function tests, Cameroon Traditional Medicine
Products have been developed to provide palliation for persons with dry mouth. In addition to mouth-wetting agents, some products incorporate antimicrobial constituents with the goal of improving oral microbial defenses. The aim of this in vitro study was to investigate the potential antimicrobial and antifungal effects of two commercially available saliva substitutes on Streptococcus mutans, Lactobacillus acidophilus, and Candida albicans by using the agar-well diffusion method. Antimicrobial activity as measured by the size of the inhibition zone growth for S. mutans and L. acidophilus was observed only with Biotene Dry Mouth Oral Rinse® and BioXtra® gel. The zone of inhibition of Biotene Dry Mouth Oral Rinse was larger than that of BioXtra gel (p= 0.00, p < 0.01). No anticandidal effect was seen with any of the test products. The pH of the preparations, the variations between the amount of active ingredients within the products, and the potential antimicrobial effects of inactive ingredients should be investigated to determine the factors that impacted microbial inhibition. PMID:21729120
Güneri, Pelin; Alpöz, Esin; Epstein, Joel B; Çankaya, Hülya; Ate?, Mustafa
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
Incorporating antimicrobial compounds into edible films or coatings provides a novel way to improve the safety and shelf life of ready-to-eat foods. Diverse studies with Quillaja saponaria Mol. (popularly named quillay) extracts have demonstrated their potential as antifungal agents against phytopathogenic fungi. Crosslinking induced by ionizing radiation is an effective method for the improvement of both barrier and mechanical properties of the edible films and coatings based on milk proteins. However there are few reports about the effects of ?-radiation on plant extracts. The aim of this work was to evaluate the effect of ionizing radiation (0, 5, 10, 15, 20, 25 and 35 kGy) on extracts prepared from in vitro plants of Q. saponaria to be used as antimicrobialagent in irradiated edible coating based on calcium caseinate and whey protein isolated, and also to establish the concentration of Q. saponaria extract to be added as an antifungal agent in the coating. Gamma irradiation since 15 kGy affects negatively the antimicrobial activity and metabolites composition of extract of Q. saponaria by reducing compounds of phenolic nature. Otherwise no effect on saponins profile was observed even at higher doses. It was possible to conclude that the antifungal activity of Q. saponaria extract is mainly related to phenolic compounds content. In addition, our work also shows that to obtain an efficient antifungal protection is necessary to add a minimum concentration of 6% of the extract after the coating irradiation.
Zúńiga, G. E.; Junqueira-Gonçalves, M. P.; Pizarro, M.; Contreras, R.; Tapia, A.; Silva, S.
Two hundred and seven clinical isolates of Pseudomonas aeruginosa were collected at Tenri Hospital between April 2003 and March 2004. We determined the minimum inhibitory concentration (MIC) of 16 antimicrobialagents, including prulifloxacin, pazufloxacin and biapenem which were recently published in Japan, against these isolates according to the guidelines of the Clinical and Laboratory Standards Institute. For the fluoroquinolones, the rank order of activity was prulifloxacin (MIC50, 0.5 microg/ml)>ciprofloxacin (1 microg/ml)> pazufloxacin (2 microg/ml)=levofloxacin (2 microg/ml)>gatifloxacin (4 microg/ml). For the carbapenems, the rank order of activity was meropenem (MIC50, 1 microg/ml)=biapenem (1 microg/ml)>imipenem (2 microg/m)>panipenem (8 microg/ml). For the cephalosporins and monobactam, the overall rank order of activity was cefozopran (MIC50, 4 microg/ml)= ceftazidime (4 microg/ml)>cefepime (8 microg/ml)=piperacillin/tazobactam (8 microg/ml)>aztreonam (16 microg/ml)= cefoperazone/sulbactam (16 microg/ml)=cefpirome (16 microg/ml). The rates of susceptibility to antimicrobialagents as per the criteria of the Japanese Society of Antimicrobial Chemotherapy were especially high for cefozopran (63%), biapenem and meropenem (61%), and pazufloxacin (53%) and ciprofloxacin (53%). These findings suggest that prulifloxacin, pazufloxacin and biapenem, which are newly introduced, are clinically effective in the treatment of infection caused with P. aeruginosa. PMID:16379156
A novel, rapid, automated method for determining the minimum inhibitory concentrations of antimicrobial drugs within ranges acceptable for therapeutic application is described and validated in this report. By employing a simple modification of the Autobac photometer currently in use and in optically clear, modified Mueller-Hinton broth, the method utilizes forward light scattering data measured in the presence of two concentrations of the antimicrobialagent to compute the minimum inhibitory concentrations. Empirically derived regression equations which simultaneously use scattering data from two drug concentrations are employed in this computation, rather than simple breakpoint analysis in which the light scattering measured in the presence of each drug concentration is referred to a threshold level. The minimum inhibitory concentrations obtained with this new method were highly reproducible and, as shown by side by side comparisons were in excellent agreement with the minimum inhibitory cencentrations obtained with the International Collaborative Study broth dilution method. Images
The evolution of antimicrobial resistance in Salmonella isolates causing traveler's diarrhea (TD) and their mechanisms of resistance to several antimicrobialagents were analyzed. From 1995 to 2002, a total of 62 Salmonella strains were isolated from stools of patients with TD. The antimicrobial susceptibility to 12 antibiotics was determined, and the molecular mechanisms of resistance to several of them were detected as well. The highest levels of resistance were found against tetracycline and ampicillin (21 and 19%, respectively), followed by resistance to nalidixic acid (16%), which was mainly detected from 2000 onward. Molecular mechanisms of resistance were analyzed in 16 isolates. In these isolates, which were resistant to ampicillin, two genes encoding ?-lactamases were detected: oxa-1 (one isolate) and tem-like (seven isolates [in one strain concomitantly with a carb-2]). Resistance to tetracycline was mainly related to tetA (five cases) and to tetB and tetG (one case each). Resistance to chloramphenicol was related to the presence of the floR and cmlA genes and to chloramphenicol acetyltransferase activity in one case each. Different genes encoding dihydrofolate-reductases (dfrA1, dfrA12, dfrA14, and dfrA17) were detected in trimethoprim-resistant isolates. Resistance to nalidixic acid was related to the presence of mutations in the amino acid codons 83 or 87 of the gyrA gene. Further surveillance of the Salmonella spp. causing TD is needed to detect trends in their resistance to antimicrobialagents, as we have shown in our study with nalidixic acid. Moreover, such studies will lead to better treatment and strategies to prevent and limit their spread.
Cabrera, Roberto; Ruiz, Joaquim; Marco, Francesc; Oliveira, Ines; Arroyo, Margarita; Aladuena, Ana; Usera, Miguel A.; Jimenez De Anta, M. Teresa; Gascon, Joaquim; Vila, Jordi
Background and Objectives: Plants as sources of medicinal compounds have continued to play a predominant role in the maintenance of human health since ancient times. Even though several effective antifungal agents are available for oral candida infections, the failure is not uncommon because isolates of Candida albicans may exhibits resistance to the drug during therapy. The present study was conducted to evaluate the antimicrobial effects of few plant extracts on Candida albicans. An additional objective was to identify an alternative, inexpensive, simple, and effective method of preventing and controlling Candida albicans. Materials and Methods: Fine texture powder or paste form of leaves was soaked in sterile distilled water and 100% ethyl alcohol, which were kept in refrigerator at 4°C for 24 h. Then filtrates were prepared and kept in a hot air oven to get a black shining crystal powder/paste form. Stock solutions of plant extracts were inoculated on petri plates containing species of Candida albicans and incubated at 25 ± 2°C for 72 h. Results: Alcoholic curry leaves showed the maximum zone of inhibition on Candida albicans followed by aqueous tea leaves. The other plant extracts like alcoholic onion leaves, alcoholic tea leaves, alcoholic onion bulb, alcoholic aloe vera, and alcoholic mint leaves also inhibited the growth of Candida albicans but lesser extent. Conclusion: The present study renders few medicinal plants as an alternative medicines to the field of dentistry which can be used adjunct to conventional therapy of oral candidasis. PMID:24047829
The antimicrobial activities of trovafloxacin, moxifloxacin, sanfetrinem, quinupristin-dalfopristin, and 14 other antimicrobialagents against 218 Bacteroides fragilis group strains were determined. A group of 10 imipenem-resistant strains were also tested. Imipenem, meropenem, and sanfetrinem had the lowest MICs of all of the ?-lactams. Quinupristin-dalfopristin inhibited all of the strains at 2 ?g/ml. Overall, the MICs of trovafloxacin and moxifloxacin for 90% of the strains tested were 1 and 2 ?g/ml, respectively.
Betriu, Carmen; Gomez, Maria; Palau, M. Luisa; Sanchez, Ana; Picazo, Juan J.
Plant oxylipins are a large family of metabolites derived from polyunsaturated fatty acids. The characterization of mutants or transgenic plants affected in the biosynthesis or perception of oxylipins has recently emphasized the role of the so-called oxylipin pathway in plant defense against pests and pathogens. In this context, presumed functions of oxylipins include direct antimicrobial effect, stimulation of plant defense
Isabelle Prost; Sandrine Dhondt; Grit Rothe; Jorge Vicente; Maria JoseRodriguez; Neil Kift; Francis Carbonne; Gareth Griffiths; Marie-Therese Esquerre; Sabine Rosahl; Carmen Castresana; Mats Hamberg; Joelle Fournier
Streptococcuspyogenes is a common pathogen which may be associated with significant morbidity and mortality. Recent information is not readily available, in Canada, regarding the susceptibility of clinical isolates to penicillin, extended spectrum and\\/or newer agents. We collected and tested 1003 isolates of S. pyogenes to seven antimicrobialagents and found the following susceptibility rates: azithromycin 97%, ceftriaxone 100%, ciprofloxacin 99.4%,
A novel in vitro semiquantitative method was developed to investigate the influence of staphylococcal slime on the activities of 22 antimicrobialagents. Pefloxacin, teicoplanin, and vancomycin demonstrated remarkable decreases in efficacy: 30, 52, and 63%, respectively. The activity of rifampin was not significantly reduced (0.99%), whereas all other agents tested were modestly affected (<15% decrease). These data could be influential
Staphylococcus lugdunensis is an atypically virulent coagulase-negative staphylococcal species associated with acute and destructive infections that often resemble Staphylococcus aureus infections. Several types of infection caused by S. lugdunensis (e.g., native valve endocarditis, prosthetic joint infection, and intravascular catheter infection) are associated with biofilm formation, which may lead to an inability to eradicate the infection due to the intrinsic nature of biofilms to resist high levels of antibiotics. In this study, planktonic MICs and MBCs and biofilm bactericidal concentrations of 10 antistaphylococcal antimicrobialagents were measured for 15 S. lugdunensis isolates collected from patients with endocarditis, medical device infections, or skin and soft tissue infections. Planktonic isolates were susceptible to all agents studied, but biofilms were resistant to high concentrations of most of the drugs. However, moxifloxacin was able to kill 73% of isolates growing in biofilms at =0.5 mug/ml. Relative to the effect on cell density, subinhibitory concentrations of nafcillin substantially stimulated biofilm formation of most isolates, whereas tetracycline and linezolid significantly decreased biofilm formation in 93 and 80% of isolates, respectively. An unexpected outcome of MBC testing was the observation that vancomycin was not bactericidal against 93% of S. lugdunensis isolates, suggesting widespread vancomycin tolerance in this species. These data provide insights into the response of S. lugdunensis isolates when challenged with various levels of antimicrobialagents in clinical use. PMID:17158933
Resistance to antimicrobialagents in Streptococcus pneumoniae is increasing rapidly in many Asian countries. There is little recent information concerning resistance levels in Vietnam. A prospective study of pneumococcal carriage in 911 urban and rural Vietnamese children, of whom 44% were nasal carriers, was performed. Carriage was more common in children <5 years old than in those ?5 years old (192 of 389 [49.4%] versus 212 of 522 [40.6%]; P, 0.01). A total of 136 of 399 isolates (34%) had intermediate susceptibility to penicillin (MIC, 0.1 to 1 mg/liter), and 76 of 399 isolates (19%) showed resistance (MIC, >1.0 mg/liter). A total of 54 of 399 isolates (13%) had intermediate susceptibility to ceftriaxone, and 3 of 399 isolates (1%) were resistant. Penicillin resistance was 21.7 (95% confidence interval, 7.0 to 67.6) times more common in urban than in rural children (35 versus 2%; P, <0.001). More than 40% of isolates from urban children were also resistant to erythromycin, trimethoprim-sulfamethoxazole, chloramphenicol, and tetracycline. Penicillin resistance was independently associated with an urban location when the age of the child was controlled for. Multidrug resistance (resistance to three or more antimicrobialagent groups) was present in 32% of isolates overall but in 39% of isolates with intermediate susceptibility to penicillin and 86% of isolates with penicillin resistance. The predominant serotypes of the S. pneumoniae isolates were 19, 23, 14, 6, and 18. Almost half of the penicillin-resistant isolates serotyped were serotype 23, and these isolates were often multidrug resistant. This study suggests that resistance to penicillin and other antimicrobialagents is common in carriage isolates of S. pneumoniae from children in Vietnam.
Parry, Christopher M.; Diep, To Song; Wain, John; Hoa, Nguyen Thi Tuyet; Gainsborough, Mary; Nga, Diem; Davies, Catrin; Phu, Nguyen Hoan; Hien, Tran Tinh; White, Nicholas J.; Farrar, Jeremy J.
Vibrio cholerae O139 (173 strains) and O1 (221 strains) were tested for their in vitro susceptibilities to 39 antimicrobialagents. 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.
Yamamoto, T; Nair, G B; Albert, M J; Parodi, C C; Takeda, Y
Minimal inhibitory concentration of 42 antimicrobialagents was determined against 57 field strains of Actinobacillus pleuropneumoniae isolated from pigs in Spain. Penicillins, aminoglycosides, and tetracyclines had irregular activity; ticarcillin, tobramycin, and doxycycline were the most active of each group, respectively. Macrolides, vancomycin, dapsone, and tiamulin, to which strains had high rate of resistance, were almost ineffective. Thiamphenicol, colistin, rifampin, fosfomycin, mupirocin, and metronidazole had good activity, with resistance ranging between 0 and 8.8%. Finally, cephalosporins (except cephalexin) and quinolones (especially ciprofloxacin, enrofloxacin, and sparfloxacin) were the most active antibiotics against A pleuropneumoniae. PMID:8484573
Gutiérrez, C B; Píriz, S; Vadillo, S; Rodríguez Ferri, E F
Objective. The aim of this study was to evaluate the antimicrobial activity and pH changes induced by Portland cement (PC) alone and in association with radiopacifiers. Methods. The materials tested were pure PC, PC + bismuth oxide, PC + zirconium oxide, PC + calcium tungstate, and zinc oxide and eugenol cement (ZOE). Antimicrobial activity was evaluated by agar diffusion test using the following strains: Micrococcus luteus, Streptococcus mutans, Enterococcus faecalis, Pseudomonas aeruginosa, and Candida albicans. After 24 hours of incubation at 37°C, inhibition of bacterial growth was observed and measured. For pH analysis, material samples (n = 10) were placed in polyethylene tubes and immersed in 10?mL of distilled water. After 12, 24, 48, and 72 hours, the pH of the solutions was determined using a pH meter. Results. All microbial species were inhibited by the cements evaluated. All materials composed of PC with radiopacifying agents promoted pH increase similar to pure Portland cement. ZOE had the lowest pH values throughout all experimental periods. Conclusions. All Portland cement-based materials with the addition of different radiopacifiers (bismuth oxide, calcium tungstate, and zirconium oxide) presented antimicrobial activity and pH similar to pure Portland cement.
Guerreiro-Tanomaru, Juliane Maria; Cornelio, Ana Livia G.; Andolfatto, Carolina; Salles, Loise P.; Tanomaru-Filho, Mario
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 AgNO(3) 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 peaks, corresponding to the (1 1 1), (2 0 0), (2 2 0), (3 1 1), and (2 2 2) sets of lattice planes of silver. The extracts incubated with AgNO(3) showed gradual change in color of the extracts to yellowish brown, with intensity increasing during the period of incubation. Control without silver nitrate did not show any change in color. The silver nanoparticles synthesized were generally found to be spherical in shape with variable size ranging from 5 to 20 nm, as evident by Transmission Electron Microscopy. There were prominent peaks in the extracts corresponding to amide I, II and III indicating the presence of the protein, as revealed by Fourier transform infrared (FTIR) spectroscopy measurement. There were also peaks that were corresponding to aromatic rings, geminal methyls and ether linkages, indicating the presence of flavones and terpenoids responsible for the stabilization of the silver nanoparticles. The silver nanoparticles were observed to inhibit clinical strains of bacteria and fungi. The antibacterial activity was more distinct than antifungal activity. The antimicrobial activity was enhanced when polyvinyl alcohol was added as a stabilizing agent. The present work highlighted the possibility of using tissue culture-derived callus extract from the coastal saltmarsh species for the synthesis of antimicrobial silver nanoparticles. PMID:20627485
Nabikhan, Asmathunisha; Kandasamy, Kathiresan; Raj, Anburaj; Alikunhi, Nabeel M
The aim of this study was to evaluate the potential of plant suspension cultures for the production of antimicrobial activities.\\u000a The extracellular, intracellular and cell wall bound fractions of 16 heterotrophic, photoautotrophic and photomixotrophic\\u000a plant cell suspension cultures each treated with nine different elicitors were tested for the elicitor dependent production\\u000a of antimicrobial activities. Distinctly different patterns of bioactivities directed
Traditional medicine has a key role in health care worldwide. Obtaining scientific information about the efficacy and safety of the plants from our region is one of the goals of our research group. In this report, 17 plants were selected and collected in different localities from northeast Mexico. The dried plants were separated into leaves, flowers, fruit, stems, roots and bark. Each part was extracted with methanol, and 39 crude extracts were prepared. The extracts were tested for their antimicrobial activity using three Gram-negative bacterial strains (Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii), three Gram-positive bacterial strains (Enterococcus faecalis and two Staphylococcus aureus strains), and seven clinically isolated yeasts (Candida albicans, C. krusei, C. tropicalis, C. parapsilosis and C. glabrata); their antioxidant activity was tested using a DPPH free radical assay. No activity against Gram-negative bacteria was observed with any extract up to the maximum concentration tested, 1000??g?ml?1. We report here for the first time activity of Ceanothus coeruleus against S. aureus (flowers, minimal inhibitory concentration (MIC) 125??g?ml?1), C. glabrata (MICs 31.25??g?ml?1) and C. parapsilosis (MICs between 31.25 and 125??g?ml?1); Chrysanctinia mexicana against C. glabrata (MICs 31.25 ?g ml?1); Colubrina greggii against E. faecalis (MICs 250??g?ml?1) and Cordia boissieri against C. glabrata (MIC 125 ?g ml?1). Furthermore, this is the first report about antioxidant activity of extracts from Ceanothus coeruleus, Chrysanctinia mexicana, Colubrina greggii and Cyperus alternifolius. Some correlation could exist between antioxidant activity and antiyeast activity against yeasts in the species Ceanothus coeruleus, Schinus molle, Colubrina greggii and Cordia boissieri.
Salazar-Aranda, Ricardo; Perez-Lopez, Luis Alejandro; Lopez-Arroyo, Joel; Alanis-Garza, Blanca Alicia; Waksman de Torres, Noemi
Infectious diseases remain a serious and now re-emerging threat to human life, contributing to over ten million deaths per year. Treatment of major infectious diseases with antibacterial agents creates an ongoing and escalating public health issue that currently leads to more problems than solutions. By processes of adaptation and survival, bacteria consistently develop mechanisms to overcome the effects of the newest and most potent antibacterial compounds. Simultaneously, progressively fewer antibacterial agents are being developed by pharmaceutical and biotechnology companies. Although this dilemma is an inherent trade-off and has no imminent resolution, the most prudent paradigm to pursue is the judicious use of antibacterial agents in the most limited way possible to attain the desired treatment results. One straightforward approach to antimicrobial stewardship is to use a single agent as opposed to combination therapy, so as to subject bacteria to lower total antibiotic exposure whenever feasible. This article reviews current trends in antibacterial drug development and describes a context for adherence to monotherapy with newer agents. PMID:19040464
We evaluated the in vitro activities of 22 antimicrobialagents against 78 human and animal isolates belonging to two aerotolerant Campylobacter species, C. cryaerophila and C. butzleri, using a broth microdilution technique. An additional 10 antimicrobialagents were included at concentrations found in selective Campylobacter media. Strains of C. cryaerophila belonged to two DNA hybridization groups: DNA hybridization group 1A, which includes the type strain of C. cryaerophila, and DNA hybridization group 1B. The aminoglycosides, fluoroquinolones, and one tetracycline (minocycline) demonstrated the most activity against all DNA hybridization groups (C. cryaerophila DNA groups 1A and 1B and C. butzleri). Most isolates were resistant to cephalosporin antibiotics, with the exception of cefotaxime, and were variably susceptible to trimethoprim-sulfamethoxazole. C. cryaerophila DNA hybridization group 1A isolates were generally susceptible to the tetracyclines, chloramphenicol, nalidixic acid, azithromycin, erythromycin, and roxithromycin and moderately susceptible to clindamycin, trimethoprim-sulfamethoxazole, ampicillin, and ampicillin-sulbactam. The MICs of tetracyclines were higher for C. butzleri and C. cryaerophila DNA hybridization group 1B isolates than for C. cryaerophila DNA hybridization group 1A isolates, but most strains were still susceptible to doxycycline and tetracycline; all isolates were susceptible to minocycline. C. butzleri and C. cryaerophila DNA hybridization group 1B isolates were generally resistant to the macrolide antibiotics (including erythromycin), chloramphenicol, clindamycin, nalidixic acid, ampicillin, and trimethoprim-sulfamethoxazole. Differences in antimicrobial susceptibility between aerotolerant Campylobacter species and more common Campylobacter species, e.g., C. jejuni, suggest that different treatment strategies may be necessary. Strains of all three DNA hybridization groups of aerotolerant Campylobacter isolates were susceptible to colistin, polymyxin B, and rifampin at concentrations commonly used in selective media. These results suggest that primary isolation methods for Campylobacter species may need to be modified to include aerotolerant Campylobacter strains.
Although there is increasing concern about residues from personal care products entering the aquatic environment and their potential to accumulate to levels that pose a health threat to humans and wildlife, we still know little about the extent and magnitude of their presence in the aquatic environment. In this study we describe a procedure for isolation, and subsequent determination, of compounds commonly added to personal care products. The compounds of interest include UV filters with the commercial name Eusolex (homosalate, 4-methylbenzylidenecamphor, benzophenone-3, octocrylene, butylmethoxydibenzoylmethane, ethylhexyl methoxycinnamate) and two common anti-microbialagents, clorophene and triclosan. Water samples were filtered, acidified, and extracted by use of solid-phase extraction. Extracted compounds were then derivatised before analysis by gas chromatography-mass spectroscopy. By use of our method we obtained limits of detection of 13-266 ng L(-1) for UV filters, and 10-186 ng L(-1) for triclosan and clorophene. Recoveries were 82-98% for deionised water and 50-98% for natural water (seawater, pool water, lake water, and river water). Samples collected in Slovenia included seventeen recreational waters (seawater, pool water, lake water, and river water; August 2004) and four wastewaters (January 2005). The most abundant UV filter was benzophenone-3 (11-400 ng L(-1)). Of the two anti-microbialagents studied, trace amounts, only, of triclosan were present in the river Kolpa (68 ng L(-1)) and in an hospital effluent (122 ng L(-1)). PMID:17136341
Obesity and obesity-related complications are on the increase both in the developed and developing world. Since existing pharmaceuticals fail to come up with long-term solutions to address this issue, there is an ever-pressing need to find and develop new drugs and alternatives. Natural products, particularly medicinal plants, are believed to harbor potential antiobesity agents that can act through various mechanisms either by preventing weight gain or promoting weight loss amongst others. The inhibition of key lipid and carbohydrate hydrolyzing and metabolizing enzymes, disruption of adipogenesis, and modulation of its factors or appetite suppression are some of the plethora of targeted approaches to probe the antiobesity potential of medicinal plants. A new technology such as metabolomics, which deals with the study of the whole metabolome, has been identified to be a promising technique to probe the progression of diseases, elucidate their pathologies, and assess the effects of natural health products on certain pathological conditions. This has been applied to drug research, bone health, and to a limited extent to obesity research. This paper thus endeavors to give an overview of those plants, which have been reported to have antiobesity effects and highlight the potential and relevance of metabolomics in obesity research.
The purpose of the antimicrobial stewardship is to make an effort so that it tries to draw out the maximum effect by using the antimicrobialagent and to decrease the risk of side-effect, and suppress the emergence of antimicrobial resistant organisms. Antimicrobial stewardship is an activity to achieve these goals. Antimicrobial stewardship must be regarded as quality control and risk management procedure in the medical institution. Enough authorization to medical staff by the executive of the hospital is indispensable for the achievement of proper use of antimicrobialagents. Additionally, the manager of the hospital should give enough resources to support this activity. PMID:22413535
As part of the ICBG program Bioactive Agents from Dryland Biodiversity of Latin America, the present investigation was undertaken to explore the possible antimycobacterial potential of compounds derived from selected Mexican medicinal plants. Bioassay-guided fractionation of the crude extracts of Rumex hymenosepalus (Polygonaceae), Larrea divaricata (Zygophyllaceae), Phoradendron robinsonii (Loranthaceae) and Amphipteryngium adstringens (Julianiaceae) led to the isolation of several antimycobacterial compounds. Four stilbenoids, two flavan-3-ols and three anthraquinones were isolated from R. hymenosepalus. Two flavonols and nordihydroguaiaretic acid were obtained from L. divaricata. Sakuranetin was the antimycobacterial agent isolated from P. robinsonii. Two known triterpenoids and the novel natural product 3-dodecyl-1,8-dihydroxy-2-naphthoic acid were obtained from A. adstringens. In general, the isolates were identified by spectral means. The antimycobacterial activity of the secondary compounds isolated from the analysed species, as well as that of nine pure compounds previously isolated in our laboratories, was investigated; the MIC values ranged from 16 to 128 microg mL-1. Among the tested compounds, the glycolipids, sesquiterpenoids and triterpenoids showed the best antimycobacterial activity. The antimycobacterial property of the glycolipids is reported for the first time. Although the tested compounds showed moderate antimycobacterial activity, their presence in the analysed species provides the rationale for their traditional use in the treatment of tuberculosis. PMID:16105233
Rivero-Cruz, Isabel; Acevedo, Laura; Guerrero, José A; Martínez, Sergio; Bye, Robert; Pereda-Miranda, Rogelio; Franzblau, Scott; Timmermann, Barbara N; Mata, Rachel
A survey of medicinal plants used locally in the treatment of various diseases was carried out in Bauchi State-Nigeria. A total of 84 medicinal plants were listed. Preliminary antimicrobial activity of the aqueous extracts of the plants was investigated. The results indicated that out of 84 plants, 75 exhibited antimicrobial activity against one or more of the test organisms at a concentration of 200 mg/ml. The extracts were found to show potentially interesting activity against Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli. PMID:15848012
Adamu, Harami M; Abayeh, O J; Agho, M O; Abdullahi, A L; Uba, A; Dukku, H U; Wufem, B M
One of the greatest challenges facing modern medicine is the evolution of drug resistant strains of bacteria. In addition to traditional methods of exposure to traditional bacterial organisms there is a growing concerned of the use of bacteria as bio-terrorism agents. To counter the evolution of drug resistant and potential bio-terrorism bacterial agents new antibiotic drugs must be developed. One potential source of new therapeutic agents that act via a novel mechanism of action are natural and synthetic antimicrobial peptides (AMPs). In our laboratories we have developed a series of AMPs incorporating the un-natural amino acids Tic-Oic to impart organism selectivity and potency while increasing metabolic stability. Herein the in vitro activity of these peptides, including ten new compounds, against eight potential bio-terrorism bacterial agents and three other bacterial strains is presented and discussed. These peptides exhibit a wide range of organism potency and selectivity. Calcein fluorescence leakage and circular dichroism studies were conducted to confirm that these peptides interact with zwitterionic and anionic liposomes. PMID:20558071
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
Lyme disease represents a disorder of potentially chronic proportions, and relatively little is known about the in vivo pharmacodynamic interactions of antimicrobialagents with borreliae. So far, evidence-based drug regimens for the effective treatment of Lyme disease have not been definitively established. Moreover, therapeutic failures have been reported for almost every suitable antimicrobialagent currently available. Resistance to treatment and
Klaus-Peter Hunfeld; Peter Kraiczy; Elena Kekoukh; Volker Schäfer; Volker Brade
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 microg/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 faecalis, Candida albicans, Aspergillus niger and Saccharomyces cerevisiae. Twenty-eight plant extracts showed activity against at least one of the test organisms used in the screening. On the basis of the results obtained, we conclude that the crude extracts of Dorema ammoniacum, Sphaeranthus indicus, Dracaena cinnabari, Mallotus philippinensis, Jatropha gossypifolia, Aristolochia indica, Lantana camara, Nardostachys jatamansi, Randia dumetorum and Cassia fistula exhibited significant antimicrobial activity and properties that support folkloric use in the treatment of some diseases as broad-spectrum antimicrobialagents. This probably explains the use of these plants by the indigenous people against a number of infections. PMID:16678369
Kumar, V Prashanth; Chauhan, Neelam S; Padh, Harish; Rajani, M
The influence of antimicrobialagents on the development of antimicrobial resistance (AMR) in Campylobacter isolates recovered from 300 beef cattle maintained in an experimental feedlot was monitored over a 315-day period (11 sample times). Groups of calves were assigned to one of the following antimicrobial treatments: chlortetracycline and sulfamethazine (CS), chlortetracycline alone (Ct), virginiamycin, monensin, tylosin phosphate, and no antimicrobialagent (i.e., control treatment). In total, 3,283 fecal samples were processed for campylobacters over the course of the experiment. Of the 2,052 bacterial isolates recovered, 92% were Campylobacter (1,518 were Campylobacter hyointestinalis and 380 were C. jejuni). None of the antimicrobial treatments decreased the isolation frequency of C. jejuni relative to the control treatment. In contrast, C. hyointestinalis was isolated less frequently from animals treated with CS and to a lesser extent from animals treated with Ct. The majority (?94%) of C. jejuni isolates were sensitive to ampicillin, erythromycin, and ciprofloxacin, but more isolates with resistance to tetracycline were recovered from animals fed Ct. All of the 1,500 isolates of C. hyointestinalis examined were sensitive to ciprofloxacin. In contrast, 11%, 10%, and 1% of these isolates were resistant to tetracycline, erythromycin, and ampicillin, respectively. The number of animals from which C. hyointestinalis isolates with resistance to erythromycin and tetracycline were recovered differed among the antimicrobial treatments. Only Ct administration increased the carriage rates of erythromycin-resistant isolates of C. hyointestinalis, and the inclusion of CS in the diet increased the number of animals from which tetracycline-resistant isolates were recovered. The majority of C. hyointestinalis isolates with resistance to tetracycline were obtained from cohorts within a single pen, and most of these isolates were recovered from cattle during feeding of a forage-based diet as opposed to a grain-based diet. The findings of this study show that the subtherapeutic administration of tetracycline, alone and in combination with sulfamethazine, to feedlot cattle can select for the carriage of resistant strains of Campylobacter species. Considering the widespread use of in-feed antimicrobialagents and the high frequency of beef cattle that shed campylobacters, the development of AMR should be monitored as part of an on-going surveillance program.
Inglis, G. D.; McAllister, T. A.; Busz, H. W.; Yanke, L. J.; Morck, D. W.; Olson, M. E.; Read, R. R.
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
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  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 antimicrobialagents 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.  Raskin, D.M.; de Boer, P. (1999) Proc. Natl. Acad. Sci. 96: 4971-4976.  Touhami, A.; Jericho, M; Rutenberg, A. (2006) J. Bacteriol. 188: 7661-7667.  Downing, B.; Rutenberg, A.; Touhami, A.; Jericho, M. (2009) PLoS ONE 4: e7285.
Kelly, Corey; Giuliani, Maximiliano; Dutcher, John
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  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 antimicrobialagents 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]  Raskin, D.M.; de Boer, P. (1999) Proc Natl. Acad. Sci. 96: 4971-4976.[0pt]  Colville, K.; Tompkins, N.; Rutenberg, A. D.; Jericho, M. H. (2010) Langmuir 2010:26.[0pt]  Downing, B.; Rutenberg, A.; Touhami, A.; Jericho, M. (2009) PLoS ONE 4: e7285.
Kelly, Corey; Murphy, Megan; Giuliani, Maximiliano; Dutcher, John
A series of soft quaternary ammonium antimicrobialagents, which are analogues to currently used quaternary ammonium preservatives such as cetyl pyridinium chloride and benzalkonium chloride, were synthesized. These soft analogues consist of long alkyl chain connected to a polar headgroup via chemically labile spacer group. They are characterized by facile nonenzymatic and enzymatic degradation to form their original nontoxic building blocks. However, their chemical stability has to be adequate in order for them to have antimicrobial effects. Stability studies and antibacterial and antiviral activity measurements revealed relationship between activity, lipophilicity, and stability. Their minimum inhibitory concentration (MIC) was as low as 1 microg/mL, and their viral reduction was in some cases greater than 6.7 log. The structure-activity studies demonstrate that the bioactive compounds (i.e., MIC for Gram-positive bacteria of <10 microg/mL) have an alkyl chain length between 12 and 18 carbon atoms, with a polar headgroup preferably of a small quaternary ammonium group, and their acquired inactivation half-life must be greater than 3 h at 60 degrees C. PMID:12954069
Preliminary studies of flavonoids have been realised in five native species from Tafí del Valle (Tucumán, Argentina) used in popular medicine. Most of compounds detected were flavonoids mono and dihydroxylated in B ring. Screening for antimicrobial activity against Gram positive and Gram negative microorganisms has been realised with Lippia turbinata, Satureja parvifolia, Sambucus peruviana, Verbena officinalis and Chenopodium graveolens. The total extracts of flavonoids of each plant were tested and four species studied showed antimicrobial activity. PMID:11025172
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
The authors examined whether decomposition of rayon in environment is suppressed by coating it with antimicrobialagent DC5700 and poval (PVA). When the rayon samples coated with DC5700 were decomposed in activated sludge or bark compost toge ther with non-coated samples, the coated samples needed longer time for the decomposition comparing to the non-coated samples under the environmental condition whose water content is 56% or less. Moreov er, PVA coating together with DC5700 further extended the decomposition time of rayon samples under the condition whose water content is 40% or less. The dyeing test of DC5700 using bromphenol blue indicated that PVA coating together with DC5700 prevented DC5700 from removing from the rayon su rface under the low-water-con tent condition and thus the double coating sample was decomposed slowly.
The in vitro activities of 47 antimicrobialagents against 30 isolates of Campylobacter species from pigs were determined by the agar dilution technique. The isolates were obtained from pigs with proliferative enteritis and included 10 strains each of Campylobacter coli, Campylobacter sputorum subsp. mucosalis, and "Campylobacter hyointestinalis Gebhart et al." (this name is not on the Approved Lists). Carbadox, furazolidone, nitrofurantoin, gentamicin, and dimetridazole were the most active drugs, inhibiting all three Campylobacter species with a MIC for 50% of the isolates of 2 micrograms/ml or less. Trimethoprim-sulfamethoxazole, cefazolin, sulfachloropyridazine, novobiocin, vancomycin, sulfathiazole, cyclohexamide, bacitracin, p-arsanilic acid, and colistin were the least active, with MICs for 50% of the isolates ranging from 16 to greater than or equal to 128 micrograms/ml.
Strains of Streptococcus mutans were isolated from blood cultures of ten patients with endocarditis. Nine of these patients had a typical clinical picture of subacute bacterial endocarditis, with fever, weakness, heart murmur and multiple positive blood cultures. All the patients had previous valvular heart diseases; only in three cases the initiating event involved some type of dental manipulations which where supposed as the source of infection. The major criteria for recognizing S. mutans were colony morphology on blood agar, characteristic extracellular polysaccharide production in 5% sucrose broth, acid formation in mannitol and sorbitol broth, and the failure of antigenic extracts of S. mutans to react with streptococcal group antisera. The susceptibility to antimicrobialagents was tested by the diffusimetric method with susceptibility disks. All the strains were susceptible to penicillin G, erythromycin, pristinamycin, lincomycin and tetracycline, and resistant to streptomycin and gentamicine. PMID:900695
The synthesis, in vitro antimicrobial activities of some novel hydroxy pyridines supported with various pharmacophores is described. Twenty-six out of the tested 58 compounds exhibited variable inhibitory effects on the growth of the tested Gram positive and Gram negative bacteria. The tested compounds revealed better activity against the Gram positive rather than the Gram negative strains. The synthesized hydroxypyridones have shown very significant inhibitory effect against Staphylococcus aureus and Bacillus subtilis. Twelve compounds namely; 5d, 5f, 6a, 6b, 8b, 18b, 18c, 19c, 21d, 22b, 22d and 23d were able to produce appreciable growth inhibitory activity against Candida albicans when compared to Clotrimazole. Among these, 22d proved to be the most potent antifungal agent. PMID:22803670
Faidallah, Hassan M; Rostom, Sherif A F; Khan, Khalid A; Basaif, Salem A
Pasteurella multocida exhibits nonspecific susceptibility to nonpolar antimicrobialagents such as triclosan, despite possessing an ultrastructurally typical gram-negative cell envelope. Capsulated and noncapsulated cell surface variants were examined to investigate the role outer membrane permeability plays in triclosan susceptibility. Test strains were unable to initiate growth in the presence of bile salts and were susceptible to triclosan with minimal inhibitory
The activities of linezolid, an oxazolidinone antibacterial agent active against gram-positive organisms, alone and in combination with 35 antimicrobialagents were tested in vitro against methicillin-sensitive (n = 1 to 2 strains) and methicillin-resistant (n = 8 to 10) Staphylococcus aureus strains; vancomycin-sensitive (n = 6) and vancomycin-resistant (n = 6 to 8) Enterococcus faecalis strains; vancomycin-sensitive (n = 5) and vancomycin-resistant (n = 6) Enterococcus faecium strains; penicillin-sensitive (n = 2 to 5), penicillin-intermediate (n = 5 to 6), and penicillin-resistant (n = 5 to 6) Streptococcus pneumoniae strains; Escherichia coli (n = 6); and Klebsiella pneumoniae (n = 6). The fractional inhibitory concentration indices of linezolid in combination with other antimicrobialagents for the organisms tested were generated on checkerboard broth microdilution plates prepared by a semiautomated method. Of 1,380 organism-drug combinations, 1,369 (99.2%) combinations of linezolid with 28 antimicrobial drugs were indifferent, 9 combinations (0.65%) of linezolid with 6 drugs (amoxicillin, erythromycin, imipenem, sparfloxacin, teicoplanin, and tetracycline) were synergistic, and 2 combinations (0.15%) of linezolid with 2 drugs (ofloxacin and sparfloxacin) were antagonistic. Overall, the in vitro data demonstrated that linezolid combined with other antimicrobialagents primarily produces an indifferent response, with infrequent occurrences of synergism and antagonism. PMID:12760865
Edible coatings with antimicrobialagents can extend shelf-life of fresh-cut fruits. The effect of lemongrass, oregano oil and vanillin incorporated in apple puree-alginate edible coatings, on shelf-life of fresh-cut 'Fuji' apples, was investigated. Coated apples were packed in air filled polypropyl...
Edible coatings with antimicrobialagents provide a novel way to improve the safety and shelf-life of fresh-cut fruit. The effect of lemongrass, oregano oil and vanillin, incorporated in apple puree-alginate edible coatings, on the shelf-life of fresh-cut Fuji apples, was investigated. Coated appl...
A novel in vitro semiquantitative method was developed to investigate the influence of staphylococcal slime on the activities of 22 antimicrobialagents. Pefloxacin, teicoplanin, and vancomycin demonstrated remarkable decreases in efficacy: 30, 52, and 63%, respectively. The activity of rifampin was not significantly reduced (0.99%), whereas all other agents tested were modestly affected (<15% decrease). These data could be influential in the treatment of implant-associated infections caused by slime-producing staphylococci.
Twenty-one antimicrobialagents were incorporated individually into Frey's agar to evaluate their inhibitory activities against 86 isolates of avian mycoplasmas recently detected in Taiwan. Among them, 45 and 37 isolates were found positive with Mycoplasma gallisepticum and Mycoplasma synoviae fluorescent antibody conjugate, respectively. Twenty-one other isolates were unable to be identified by the above 2 conjugates. All of the field isolates were highly sensitive (with MIC50 < 1 microgram/ml) to enrofloxacin, gentamicin, myplabin, tiamutin and tylosin. However, those field isolates were highly resistant (with MIC50 > 32 micrograms/ml) to apramycin, chlortetracycline (CTC), erythromycin (ER), flumequine (FI), nalidixic acid (NA), oxolinic acid (OA), oxytetracycline (OTC) and spiramycin (SP). The inhibitory activities of the antibiotics which possessed an MIC90 of 50 micrograms/ml or less against local isolates were, in decreasing order, enrofloxacin (< 0.004 microgram/ml), gentamicin (1.53 micrograms/ml), tiamutin (1.81 micrograms/ml), tylosin (3.2 micrograms/ml), streptomycin (SM; 12.0 micrograms/ml), colistin (13.1 micrograms/ml), chloramphenicol (14.0 micrograms/ml), spectinomycin (15.0 micrograms/ml), myplabin (16.0 micrograms/ml), spiramycin (30.0 micrograms/ml), minocycline (32.0 micrograms/ml). The MIC90 of OA, CTC, SM, FI, SP, OTC, ER or NA was greater than 50 micrograms/ml; which work poorly in the control of mycoplasmoses. Since the antibiotic control policy is quite loose in Taiwan, many antimicrobialagents are often freely used in clinics, with a resulting gradual decrease in the inhibitory activity to the avian mycoplasmas. PMID:9747335
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,
Jussi-Pekka Rauha; Susanna Remes; Marina Heinonen; Anu Hopia; Marja Kähkönen; Tytti Kujala; Kalevi Pihlaja; Heikki Vuorela; Pia Vuorela
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
To augment plant protection against phytopathogens, we constructed a fusion gene for the simultaneous expression of snakin-1 (SN1) and defensin-1 (PTH1) antimicrobial proteins as a hybrid protein (SAP) in plant cells. Prior to in vivo evaluation of SAP phytoprotective activity, the hybrid protein ex...
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.
Plant growth promoting rhizobacteria (PGPR) are indigenous to soil and the plant rhizosphere and play a major role in the biocontrol of plant pathogens. PGPR can profoundly improve seed germination, root development and water utilization by plants. These rhizobacteria can stimulate plant growth directly by producing growth hormones and improving nutrient uptake or indirectly by changing microbial balance in the
For centuries, indigenous people in South Africa have used a variety of medicinal herbs to treat chronic infections. This investigation focused on two Carpobrotus species belonging to the family, Aizoaceae, in an attempt to assess their antimicrobial potential. Extracts of varying polarities of the plants were prepared and tested against Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans and Mycobacterium smegmatis. For the disc diffusion method, Ciprofloxacin (40 microg/disc) served as positive control for S. aureus, P. aeruginosa and M. smegmatis, whereas amphotericin B (25 microg/disc) was the control for C. albicans. A sample concentration of 10 mg/ml was used. Minimum inhibitory concentrations (MIC) were determined by two-fold serial dilution. Phytochemical analysis was completed to test for the presence of flavonoids, hydrolysable tannins, phytosterols and aromatic acids. The ethyl acetate extracts (21 microl of 95 mg/ml) were used for bio-autography, together with TLC analyses. Carpobrotus muirii and Carpobrotus quadrifidus showed antimicrobial activity against S. aureus and M. smegmatis in the disc diffusion method and inhibition against S. aureus and M. smegmatis was observed by clear zones on the TLC plate. This investigation confirms that extracts of these Carpobrotus species that are used as indigenous medicines, exhibit anti-bacterial activity. This scientific information can serve as an important platform for the development of inexpensive, safe and effective natural anti-infective medicines. PMID:12834010
The efficacies of many antimicrobialagents are being threatened by a global increase in the numbers of resistant bacterial pathogens—microorganisms that were once susceptible to some of these agents. In particular, antimicrobial resistance amongst strains of Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae has limited the usefulness of first-line agents in some clinical settings. Quinolones were introduced in the 1980s
Widely used antimicrobial volatile organic compounds, such as sulphur dioxide and ethanol but also selected aroma compounds such as carvacrol, allyl isothiocyanate (AITC) and cinnamaldehyde, were tested single and in binary combination for their effect on Penicillium notatum growth in vapour phase at 30 degrees C. Aroma compounds were more efficient compared to sulphur dioxide and ethanol. AITC and cinnamaldehyde had the highest inhibition activity on the growth of P. notatum with minimum inhibitory concentration (MIC) of 3.8 and 3.9 micromol/L of air, respectively. The impact of agents combined two by two was assessed using two criteria, the increase of growth delay and the reduction of growth rate. A synergistic activity was identified for six combinations; ethanol/carvacrol, sulphur dioxide/carvacrol, sulphur dioxide/AITC, sulphur dioxide/cinnamaldehyde, AITC/cinnamaldehyde and cinnamaldehyde/carvacrol. The advantage of these combinations is to reduce the concentration of each agent and their relative impact in organoleptic properties. PMID:17011661
Tunc, S; Chollet, E; Chalier, P; Preziosi-Belloy, L; Gontard, N
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
Although chlorhexidine is one of the most efficacious antimicrobialagents used for the prevention of dental caries, side effects limit its application. The effects of gaegurin 6 (GGN6), an animal-derived cationic peptide, and its derivatives PTP6 and PTP12 on the growth of oral streptococci were investigated to assess the potential of these agents for use in the prevention of dental caries. The minimal inhibitory concentrations of the peptides for inhibition of the growth of oral streptococci (Streptococcus mutans , S. sobrinus, S. sanguis and S. gordonii) ranged from 1.2 to 8.2 muM. The peptides also exhibited marked synergistic antibacterial effects with chlorhexidine or xylitol. The most effective combinations (fractional inhibitory concentration index of 0.5) were xylitol with GGN6 against S. gordonii 10558 and chlorhexidine with either GGN6 or PTP6 against S. sobrinus OMZ-175. These results indicate that cationic peptides alone or in combination with chlorhexidine or xylitol might prove effective for the inhibition of the growth of cariogenic oral streptococci in situ. PMID:14571120
Kim, Sukwon S; Kim, Sunkyu; Kim, Eunshin; Hyun, Byungkuk; Kim, Kack-Kyun; Lee, Byeong Jae
The ability for silver nanoparticles to function as an antibacterial agent while being separable from the target fluids is important for bacterial inactivation in biological fluids. This report describes the analysis of the antimicrobial activities of silver-coated magnetic nanoparticles synthesized by wet chemical methods. The bacterial inactivation of several types of bacteria was analyzed, including Gram-positive bacteria ( Staphylococcus aureus and Bacillus cereus ) and Gram-negative bacteria ( Pseudomonas aeruginosa , Enterobacter cloacae , and Escherichia coli ). The results have demonstrated the viability of the silver-coated magnetic nanoparticles for achieving effective bacterial inactivation efficiency comparable to and better than that of silver nanoparticles conventionally used. The bacteria inactivation efficiency of our silver-coated MnZn ferrite (MZF@Ag) nanoparticles was also determined for blood platelets samples, demonstrating the potential of utilization in inactivating bacterial growth in platelets prior to transfusion to ensure blood product safety, which also has important implications for enabling the capability of effective separation, delivery, and targeting of the antibacterial agents. PMID:21999710
Wang, Lingyan; Luo, Jin; Shan, Shiyao; Crew, Elizabeth; Yin, Jun; Zhong, Chuan-Jian; Wallek, Brandi; Wong, Season S S
Gram-negative nonfermentative bacilli (NFB) are widely spread in the environment. Besides of difficulties for identification, they often have a marked multiresistance to antimicrobialagents, including those active against Pseudomonas aeruginosa. The objective of this study was to evaluate the 'in vitro' activity of different antimicrobialagents on 177 gram-negative nonfermentative bacilli isolates (excluding Pseudomonas aeruginosa and Acinetobacter spp.) isolated from clinical specimens. Minimum inhibitory concentrations (MIC) were determined according to the Mueller Hinton agar dilution method against the following antibacterial agents: ampicillin, piperacillin, piperacillin-tazobactam, sulbactam, cefoperazone, cefoperazone-sulbactam, ceftazidime, cefepime, aztreonam, imipenem, meropenem, colistin, gentamicin, amikacin, trimethoprim-sulfamethoxazole, chloramphenicol, erythromycin, rifampin, norfloxacin, ciprofloxacin and minocycline. Seven isolates: Sphingobacterium multivorum (2), Sphingobacteriumspiritivorum (1), Empedobacterbrevis (1), Weeksella virosa (1), Bergeyella zoohelcum (1) and Oligella urethralis (1), were tested for amoxicillin-clavulanic acid and ampicillin-sulbactam susceptibility, and susceptibility to cefoperazone or sulbactam was not determined. Multiresistance was generally found in Stenotrophomonas maltophilia, Burkholderia cepacia, Chryseobacterium spp., Myroides spp., Achromobacter xylosoxidans, and Ochrobactrum anthropi isolates. On the other hand, Pseudomonas stutzeri, Shewanella putrefaciens-algae, Sphingomonas paucimobilis, and Pseudomonas oryzihabitans, Bergeyella zoohelcum, Weeksella virosa and Oligella urethralis were widely susceptible to the antibacterial agents tested. As a result of the wide variation in antimicrobial susceptibility shown by different species, a test on susceptibility to different antibacterial agents is essential in order to select an adequate therapy. The marked multiresistance evidenced by some species, prompts the need to develop new antimicrobialagents active against this group of bacteria and to search for synergistic combinations. PMID:15991478
Vay, C A; Almuzara, M N; Rodríguez, C H; Pugliese, M L; Lorenzo Barba, F; Mattera, J C; Famiglietti, A M R
Bacterial contamination of commercial fermentation cultures is a common and costly problem to the fuel ethanol industry. Antimicrobials such as virginiamycin (VIR) and penicillin (PEN) are frequently used to control contamination but there are little data available on the susceptibility of bacteria...
The in vitro antimicrobial activity of Ankaferd Blood Stopper® (ABS) was assessed on 102 clinical isolates from both Gram negative and Gram positive bacteria and four standard strains, including MRSA ATCC 43300, MSSA ATCC 25923, P. aeruginosa ATCC 27853 and E. coli ATCC 35218. ABS was significantly active against all bacteria investigated.
Extracts from five indigenous Palestinian medicinal plants including Rosmarinus officinalis, Pisidium guajava, Punica granatum peel, grape seeds and Teucrium polium were investigated for antimicrobial and free radical scavenging activities against eight microorganisms, using well diffusion method. The microorganisms included six bacterial isolates (i.e. Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginos, Klebsiella pneumonia, Bacillus subtilis and Micrococcus luteus) and two fungal isolates (i.e. Candida albicans and Aspergillus niger). A standard antioxidant assay was performed on the plant extracts to assess their capability in scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH). Of the five tested plant extract, only Rosmarinus offcinalis extract contained significant antimicrobial activity against all eight microbial isolates including Pseudomonas aeruginosa. Extracts from other four plants exhibited a variable antimicrobial activity against all microorganisms, except Pseudomonas aeruginosa. Significant antioxidant activity was detected in all plant extracts. However, extracts from Pisidium guajava leaves contained significantly higher antioxidant activity compared to the other extracts tested. The antimicrobial and scavenging activities detected in this in vitro study in extracts from the five Palestinian medicinal plants suggest that further study is needed to identify active compounds to target diseases caused by a wide-spectrum pathogens. PMID:24146509
The current study focuses on the preparation of new N-(cinnamyl) chitosan derivatives as antimicrobialagents 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
The fungus Muscodor albus produces a mixture of antimicrobial volatile organic chemicals with activity against post-harvest disease causing organisms, insect pests of harvested fruit and tubers, and soil-borne disease causing agents and plant parasitic nematodes. M. albus was tested for its potenti...
Objectives: The Alexander Project is a continuing surveillance study, begun in 1992, examining the suscep- tibility of pathogens involved in adult community-acquired respiratory tract infections (CARTI) to a range of antimicrobialagents. Materials and methods: This study tested the susceptibility of isolates of Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis collected between 1998 and 2000 to 23 antimicrobials. Minimum inhibitory
Michael R. Jacobs; David Felmingham; Peter C. Appelbaum; Reuben N. Grüneberg
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 DNA encoding bactericidal proteins to bacteria. To test the concept of using phage as a lethal-agent delivery vehicle, we used the M13 phagemid system and the addiction toxins Gef and ChpBK. Phage delivery of lethal-agent phagemids reduced target bacterial numbers by several orders of magnitude in vitro and in a bacteremic mouse model of infection. Given the powerful genetic engineering tools available and the present knowledge in phage biology, this technology may have potential use in antimicrobial therapies and DNA vaccine development.
Westwater, Caroline; Kasman, Laura M.; Schofield, David A.; Werner, Phillip A.; Dolan, Joseph W.; Schmidt, Michael G.; Norris, James S.
The Eastern Black Sea Region has an extensive flora because of ample rainfall lasting all year. In this study, antimicrobial effects of 74 crude extracts of 22 endemic plants were investigated. Among the 30 active crude extracts, water-insoluble crude extracts from Betula medwediewii, Heracleum platytaenium, Primula longipes, Anthemis cretica ssp. argaea and Centaurea helenioides were the prominent ones with their
Kurtulus Buruk; Atalay Sokmen; Faruk Aydin; Murat Erturk
Anti-microbial activity and phytochemical constituents of methanol extract of Plumeria rubra (flower and leaf) and Eucalyptus globules (leaf) was investigated. Phytochemical screening of the crude extract revealed the presence of tannins, phlobatannins, saponins, flavonoids, steroids, terpenoids, cardiac glycosides and reducing sugar in the plants investigated. Phlobatanins were found to be absent in the methanol extract of Plumeria rubra (flower) and
Edible films, as carriers of antimicrobial compounds, constitute an approach for incorporating plant essential oils onto fresh-cut fruit surfaces. The effect against Escherichia coli O157:H7 of oregano, cinnamon and lemongrass oils in apple puree film-forming solution (APFFS) and in an edible film ...
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
We determined MICs of 20 antimicrobialagents for 50 representative strains of four subgroups of Campylobacter-like organisms (CLOs) by agar dilution. Ampicillin, gentamicin, doxycycline, tetracycline, ceftriaxone, rifampin, spectinomycin, nalidixic acid, and chloramphenicol were active against all strains of CLOs. Most CLO strains (83%) were inhibited by 4 micrograms of sulfamethoxazole per ml and by 8 micrograms of trimethoprim-sulfamethoxazole per ml. Of type 1 strains, 28% were resistant to 8 micrograms of erythromycin per ml. In addition, cross resistance between erythromycin and clindamycin was always present. Type 1 strains exhibited a broad distribution of MICs of metronidazole and streptomycin, whereas all type 2 strains were uniformly susceptible to metronidazole and resistant to streptomycin. Unlike type 1 and 3 strains, type 2 CLOs were susceptible to cephalothin and penicillin G and highly resistant to streptomycin. The type 3 strain was uniquely resistant to cefazolin. The majority of strains were not inhibited by cefoperazone; and all were resistant to trimethoprim. In contrast to Campylobacter jejuni and Campylobacter fetus subsp. fetus, all CLOs tested were susceptible to 0.5 microgram of rifampin per ml.
Flores, B M; Fennell, C L; Holmes, K K; Stamm, W E
There is considerable need for new modeling approaches in the study of combined antimicrobial effects. Current methods based on the Loewe additivity and Bliss independence models are associated with implicit assumptions about the interacting system. To circumvent these limitations, we propose an alternative approach to the quantification of pharmacodynamic drug interaction (PDI). Pilot time-kill studies were performed with 108 CFU of Pseudomonas aeruginosa/ml at baseline with meropenem or tobramycin alone. The studies were repeated with 25 concentration combinations of meropenem (0 to 64 mg/liter) and tobramycin (0 to 32 mg/liter) in a five-by-five array. The data were modeled with a three-dimensional response surface using effect summation as the basis of null interaction. The interaction index (Ii) is defined as the ratio of the volumes under the planes (VUP) of the observed and expected surfaces: VUPobserved/VUPexpected. Synergy and antagonism are defined as Ii values of <1 and >1, respectively. In all combinations, an enhanced killing effect was seen compared to that of either drug at the same concentration. The most significant synergism was observed between 1 and 5 mg/liter of meropenem and between 1 and 4 mg/liter of tobramycin; seven out of nine combinations had a >2-log drop compared to the more potent agent. The Ii was found to be 0.76 (95% confidence interval, 0.65 to 0.91) for the concentration ranges of the agents. The results corroborate previous data indicating that meropenem is synergistic with an aminoglycoside when used in combination against P. aeruginosa. Our parametric approach to quantifying PDI appears robust and warrants further investigations.
Tam, Vincent H.; Schilling, Amy N.; Lewis, Russell E.; Melnick, David A.; Boucher, Adam N.
The in vitro activity of WIN 57273, a new fluoroquinolone antimicrobialagent, was evaluated against approximately 600 bacterial isolates. The new drug was 4- to 128-fold more active than ciprofloxacin against a broad range of gram-positive organisms, with the new drug inhibiting 90% of strains of each species except Enterococcus faecium at concentrations of less than or equal to 0.25 microgram/ml. WIN 57273 was four- to eightfold less active than ciprofloxacin against many members of the family Enterobacteriaceae, but the MICs of the new drug for 90% of strains tested (MIC90s) were less than or equal to 8 micrograms/ml (range, 0.25 to 8 micrograms/ml) for all species. Branhamella catarrhalis, Haemophilus influenzae, Neisseria gonorrhoeae, and Legionella spp. were highly susceptible (MIC90s, less than or equal to 0.06 microgram/ml). WIN 57273 demonstrated excellent activity against anaerobes (MIC90s, less than or equal to 0.25 microgram/ml), and the drug was also more active than ciprofloxacin against 30 strains of Mycobacterium avium-M. intracellulare (MIC, 0.1 to 1.0 microgram/ml). The activity of WIN 57273 against gram-positive organisms was minimally affected by pH and increased at low pH (5.4) against gram-negative organisms. The bactericidal activity of WIN 57273 was demonstrated by time-kill techniques against selected organisms. The frequencies of spontaneous resistance to the new agent were low, but resistant colonies could be selected after serial passage of initially susceptible organisms through incremental concentrations of the drug.
Eliopoulos, G M; Klimm, K; Rice, L B; Ferraro, M J; Moellering, R C
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.
A multicenter study was performed to evaluate the susceptibility of beta-hemolytic streptococci to nine antimicrobialagents. MICs were performed in cation-supplemented Mueller-Hinton broth with 3.5% lysed sheep red blood cells according to NCCLS guidelines. A total of 646 isolates were tested: 300 (46%) group A; 170 (26%) group B; 38 (6%) group C, 35 (5%) group F; 83 (17%) group
Karen C. Carroll; Patricia Monroe; Samuel Cohen; Mark Hoffman; Leslie Hamilton; Kent Korgenski; Larry Reimer; David Classen; Judy Daly
\\u000a Introduction Previous prospective study in our unit had shown that the use of dual antibiotic prophylaxis in patients with external ventricular\\u000a drain was associated with decreased incidence of cerebrospinal fluid infection but complicated with opportunistic extracranial\\u000a infection. In recent years, cerebrospinal fluid shunt catheters impregnated with antimicrobialagents have become available.\\u000a Theoretically, these catheters provide antibiotic prophylaxis locally without the
George K. C. Wong; W. S. Poon; Stephanie C. C. P. Ng; Margaret Ip
Bacillus amyloliquefaciens LBM 5006 produces an antimicrobial factor active against Paenibacillus larvae, a major honeybee pathogen. The antagonistic effect and the mode of action of the antimicrobial factor were investigated.\\u000a The antibacterial activity was produced starting at mid-logarithmic growth phase, reaching its maximum during the stationary\\u000a phase. Exposure of cell suspensions of P. larvae to this antimicrobial resulted in loss
Lisianne Brittes Benitez; Renata Voltolini Velho; Amanda de Souza da Motta; Jéferson Segalin; Adriano Brandelli
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.
The present report constitutes an attempt to improve and modify the existing clinical evaluation method for new antimicrobial\\u000a agents to treat respiratory infections. One year ago, a general guideline on the clinical evaluation of antimicrobialagents\\u000a to treat respiratory infections was drafted in Japanese, leaving scope for critical discussion, and this has been translated\\u000a into English, as there were no
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 Phagnalon rupestre and Micromeria nervosa, whereas, the least active plant was Ziziphus spina-christi. Only ten of the tested plant extracts were active against C. albicans, with the most active from M. nervosa and Inula viscosa and the least active from Ruscus aculeatus. Of all extracts the ethanolic extract of M. nervosa was the most active, whereas, the aqueous extract of Phagnalon rupestre was the most active of all aqueous extracts tested. The ethanolic extracts (70%) showed activity against both Gram positive and negative bacteria and 40% of these extracts showed anticandidal activity, whereas, 50% of the aqueous extracts showed antibacterial activity and 20% of these extracts showed anticandidal activity. PMID:9613839
Ali-Shtayeh, M S; Yaghmour, R M; Faidi, Y R; Salem, K; Al-Nuri, M A
Antimicrobials are used emperically in a variety of inflammatory dermatoses such as rosacea and dermatitis herpetiformis, although these diseases are not believed to be of bacterial etiology. We have used potassium iodide ointment to induce follicular pustules and have found in this in vivo model properties of antimicrobials not related to their antibacterial actions. Topical demethylchlortetracycline and erythromycin (5%) lead
ABSTRACT. This article introduces a set of principles to define judicious antimicrobial use for five conditions that account for the majority of outpatient antimicrobial use in the United States. Data from the National Center for Health Statistics indicate that in recent years, approx- imately three fourths of all outpatient antibiotics have been prescribed for otitis media, sinusitis, bronchitis, pharyngitis, or
Scott F. Dowell; S. Michael Marcy; William R. Phillips; Michael A. Gerber; Benjamin Schwartz
The antimicrobial efficacy of alcohol-based hand gels has been shown to be significantly less than liquid hand rubs probably because of a lower concentration of alcohol. Sterillium Gel is the first hand gel with 85% ethanol. Its antimicrobial efficacy and user acceptability was studied. Bactericidal activity was tested according to prEN 12054 against Staphylococcus aureus, Enterococcus hirae, Pseudomonas aeruginosa and
Antimicrobials given in subtherapeutic levels in feed are credited with having contributed to lower cost of meat, milk and eggs. The practice often is associated with the acquisition of resistant enteric flora by the involved animals, and this may in turn contribute to the human reservoir of antimicrobial resistant coliforms and salmonellae. Associated farm workers may transiently acquire resistant flora
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
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
The agar dilution method was used to determine the activities of gentamicin, erythromycin, streptomycin, chloramphenicol, ampicillin, sulfamethazine, cephalothin, penicillin G, and tetracycline against 73 strains belonging to the genus Listeria (L. innocua, L. seeligeri, and L. monocytogenes). All strains were isolated from raw milk, cheese, the dairy processing plant, poultry, and the poultry slaughterhouse. Gentamicin, ampicillin, and erythromycin, of which the MICs for 90% of the strains tested for all three species were < or = 5.96 micrograms/ml, were found to be the most active agents studied. Most of the L. innocua strains isolated from poultry and the poultry slaughterhouse were resistant to tetracycline.
Franco Abuin, C M; Quinto Fernandez, E J; Fente Sampayo, C; Rodriguez Otero, J L; Dominguez Rodriguez, L; Cepeda Saez, A
Objective: To evaluate the antimicrobial activity of Momordica charantia extracts on reference strains and microorganisms isolated from clinical specimens. Method: Petroleum ether and methanolic crude extracts of fruits and leaves of the plant were evaluated for antimicrobial activity using the disk diffusion method on four reference microorganisms (Pseudomonas aeruginosa, Escherichia coli, Candida albicans and Staphylococcus aureus; and four clinical strains
Supercritical fluid extracts of three Myanmar natural plants, namely, Curcuma aeruginosa, Citrus hystrix, and Azadirachta indica A. Juss were screened for antimicrobial activity against different strains of bacteria and yeast, which are known to cause various types of skin infections. The antimicrobial activity was tested on Bacillus cereus, Bacillus subtilis, Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, Propionibacterum acnes, and Malassezia
Three glutamic acid derivatives, two boron-containing and one imide-containing compound, were synthesized and tested for antimicrobial activity targeting glutamate-racemase. Antimicrobial effect was evaluated over Bacillus spp. Docking analysis shown that the test compounds bind near the active site of racemase isoforms, suggesting an allosteric effect. The boron derivatives had greater affinity than the imide derivative. In vitro assays shown good antimicrobial activity for the boron-containing compounds, and no effectiveness for the imide-containing compounds. The minimum inhibitory concentration of tetracycline, used as standard, was lower than that of the boron-containing derivatives. However, it seems that the boron-containing derivatives are more selective for bacteria. Experimental evidence suggests that the boron-containing derivatives act by inhibiting the racemase enzyme. Therefore, these test compounds probably impede the formation of the bacterial cell wall. Thus, the boron-containing glutamic acid derivatives should certainly be of interest for future studies as antimicrobialagents for Bacillus spp. PMID:22871135
Tamay-Cach, Feliciano; Correa-Basurto, José; Villa-Tanaca, Lourdes; Mancilla-Percino, Teresa; Juárez-Montiel, Margarita; Trujillo-Ferrara, José G
Liquid smoke extracts have traditionally been used as flavoring agents, are known to possess antioxidant properties, and serve as natural alternatives to conventional antimicrobials. The antimicrobial efficacies of commercial liquid smoke samples may vary depending on their source and composition and the methods used to extract and concentrate the smoke. We investigated the MICs of eight commercial liquid smoke samples against Salmonella Enteritidis, Staphylococcus aureus, and Escherichia coli . The commercial liquid smoke samples purchased were supplied by the manufacturer as water-based or concentrated extracts of smoke from different wood sources. The MICs of the commercial smokes to inhibit the growth of foodborne pathogens ranged from 0.5 to 6.0% for E. coli, 0.5 to 8.0% for Salmonella, and 0.38 to 6% for S. aureus. The MIC for each liquid smoke sample was similar in its effect on both E. coli and Salmonella. Solvent-extracted antimicrobials prepared using pecan shells displayed significant differences between their inhibitory concentrations depending on the type of solvent used for extraction. The results indicated that the liquid smoke samples tested in this study could serve as effective natural antimicrobials and that their inhibitory effects depended more on the solvents used for extraction than the wood source. PMID:22691487
Van Loo, Ellen J; Babu, D; Crandall, Philip G; Ricke, Steven C
Arthropathy in dogs induced by ofloxacin, a quinolone antimicrobialagent, was pathophysiologically investigated. In the in vivo studies, ofloxacin was administered orally once or twice at 20 mg/kg/day to male juvenile (3-month-old, n=3) or adult (36-month-old, n=2) dogs, and the humeral and femoral heads were examined pathologically. Unlike adult dogs, fluid-filled vesicles were macroscopically observed on the articular surfaces of one juvenile dog 24 hours after a single treatment with ofloxacin. These lesions were seen in all juvenile dogs by twice dosing. Microscopically, fissures or cavity formations in the middle zone of the articular cartilage were noted only in juvenile dogs. Furthermore, the cartilage matrix from the abnormal area to the articular surface showed a decreased safranin-O staining intensity, suggesting proteoglycan depletion. Ultrastructurally, chondrocytes in the middle zone of juvenile dogs displayed dilatation of the cisternae in the rough endoplasmic reticulum as an initial hallmark. In the in vitro studies, chondrocytes isolated from the articular cartilage of naive juvenile dogs were exposed to ofloxacin at 6.3-100 microg/ml for 24 hours. Although no changes were noted in the deoxyribonucleic acid synthesis, protein synthesis, or proteoglycan release at concentrations of up to 100 microg/ml, the proteoglycan synthesis was evidently decreased in a dose-dependent manner from 12.5 microg/ml. The results obtained suggest that the inhibitory action of ofloxacin on proteoglycan syntheses in the chondrocytes may largely contribute to the early morphologic features in the articular cartilage of the juvenile dog. PMID:15557076
Yabe, K; Satoh, H; Ishii, Y; Jindo, T; Sugawara, T; Furuhama, K; Goryo, M; Okada, K
Background: The use of antimicrobial peptides (AMPs) as therapeutic agents for periodontal infections has great advantages, such as its broad spectrum of action, low toxicity, and limited bacterial resistance. However, its practical use is limited due to the large amount of peptide required to exercise its microbicide function. Methods: LyeTxI, LL37f, and KR12 cationic peptides were prepared with ?-Cyclodextrin (?CD) at 1:1 molar ratio. The susceptibility of Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Fusobacterium nucleatum were assessed in anaerobic conditions. Cytotoxicity assays were performed using osteoblast and Caco-2 epithelial cells, and hemolytic activity on rabbit erythrocytes at an absorbance of 414 nm. Parameters of roughness and electrical charge of membrane were established by Atomic Force Microscopy (AFM) and Zeta potential, respectively. Results: The AMPs/?CD decreased drastically the peptide concentration required for activity against bacteria tested. Moreover, AMPs associated to ?CD were able to modify the cell surface parameters, such as roughness and zeta potential. On the other hand, AMP/?CD did not alter the degree of hemolysis induced by the pure AMPs. The ECs50 values of the peptides and compounds on osteoblast were greater than the concentrations required to achieve inhibition of bacterial growth in all the species tested. The AMP/?CD inhibited the proliferation of Caco-2 epithelial cells in a more efficient manner than AMPs solely. Conclusion: AMPs/?CDs are more efficacious to inhibit periodontopathogenic bacteria with additional ability of inhibiting the proliferation of epithelial cells at non-cytotoxic concentrations for osteoblasts and erythrocytes. PMID:23510146
Consuegra, Jessika; Elena de Lima, Maria; Santos, Daniel; Sinisterra, Rubén Dario; Cortés, Maria Esperanza
Strains of Acanthamoeba sp. constitute a factor contributing to the occurrence of chronic granulomatous amoebic encephalitis, keratitis, pneumonia,\\u000a as well as inflammations of other organs. Treatment of these diseases is very difficult and not always effective. A majority\\u000a of these infections have been fatal. The aim of our study was to examine the amoebicidal or amoebistatic activity of plant\\u000a extracts
Strains of Acanthamoeba sp. constitute a factor contributing to the occurrence of chronic granulomatous amoebic encephalitis, keratitis, pneumonia, as well as inflammations of other organs. Treatment of these diseases is very difficult and not always effective. A majority of these infections have been fatal. The aim of our study was to examine the amoebicidal or amoebistatic activity of plant extracts from Rubus chamaemorus, Pueraria lobata, Solidago virgaurea and Solidago graminifolia. For the purpose of isolation of pharmacologically active substances, we used the aboveground parts of plants, together with flowers, roots and leaves. It was established that extracts from S. virgauera, P. lobata and R. chamaemorus displayed chemotherapeutic properties in vitro in concentrations of approximately 0.01-0.05 mg extract/mL, i.e., in concentrations of 0.350 microg/mL expressed in ellagic acid for R. chamaemorus and 0.053 microg/mL expressed in puerarin for P. lobata. Therapeutic index values is 3.5-20. As a result of in vivo experiments, it was found out that, following therapy using the extracts, animals infected with Acanthamoeba sp. survived for an extended period (2.5-3 times longer). It was determined that plant extracts may be used both externally and internally in the case of a combined therapy for acanthamoebiasis. The tested extracts are not toxic for animals. PMID:19050923
The aim of our study was to evaluate antimicrobial use in dogs and cats in Finland. Information on veterinary prescriptions was gathered from University Pharmacies (n = 17) over a one-month period, April 2001. A total of 2719 prescriptions for veterinary use were delivered, of which the majority were for dogs (70%, n = 1898) and cats (14%, n = 384). The most prescribed therapy group was per-oral antimicrobialagents (53%, n = 1449), of which 16% (n = 237) were medicines approved for humans. The most commonly used substances for dogs and cats were betalactams, 66% and 78%, respectively. The proportion of fluoroquinolones was 3–5%. The average duration of the treatment periods was 10 days with the exception of treatment of cats with macrolide lincosamides, where the mean period was 20 days. Indication was mentioned only in 37% of the prescriptions.
Holso, K; Rantala, M; Lillas, A; Eerikainen, S; Huovinen, P; Kaartinen, L
Peptides and small proteins exhibiting antimicrobial activity have been isolated from many organisms ranging from insects to humans, including plants. Their role in defense is established, and their use in agriculture was already being proposed shortly after their discovery. However, some natural peptides have undesirable properties that complicate their application. Advances in peptide synthesis and high-throughput activity screening have made possible the de novo and rational design of novel peptides with improved properties. This review summarizes findings in the identification and design of short antimicrobial peptides with activity against plant pathogens, and will discuss alternatives for their heterologous production suited to plant disease control. Recent studies suggest that peptide antimicrobial action is not due solely to microbe permeation as previously described, but that more subtle factors might account for the specificity and absence of toxicity of some peptides. The elucidation of the mode of action and interaction with microbes will assist the improvement of peptide design with a view to targeting specific problems in agriculture and providing new tools for plant protection. PMID:18439131
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 antimicrobialagents (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 antimicrobialagents. 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
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
The rhizomes of the Zingiberaceae family are a vegetable widely used in many Asian countries, and their medicinal functions\\u000a have been broadly discussed and accepted in many traditional recipes. In this study, 18 species of five genus of Zingiberaceae\\u000a plants from Taiwan area were collected and analyzed for their functional properties. Methanolic extracts of the plants were\\u000a analyzed for their
The Eastern Black Sea Region has an extensive flora because of ample rainfall lasting all year. In this study, antimicrobial effects of 74 crude extracts of 22 endemic plants were investigated. Among the 30 active crude extracts, water-insoluble crude extracts from Betula medwediewii, Heracleum platytaenium, Primula longipes, Anthemis cretica ssp. argaea and Centaurea helenioides were the prominent ones with their MIC values. PMID:16716535
Buruk, Kurtulus; Sokmen, Atalay; Aydin, Faruk; Erturk, Murat
This study reports the identification and demonstration of an organism with antimicrobial activity isolated from activated\\u000a biomass of an effluent treatment plant (ETP) treating wastewater containing pesticides. While assessing the heterotrophic\\u000a diversity of biomass collected from ETP, clear zones were observed on Luria Bertani plates. The bacterial isolate producing\\u000a the zone as well as the bacterial cells surrounding the zone
Atya Kapley; Sameera N. Siddiqui; Hemant J. Purohit
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
Endophytic filamentous fungi from coffee plants (Coffea arabica and C. robusta) deposited in the Brazilian Collection of Environmental and Industrial Microorganisms (CBMAI) were characterized taxonomically by using molecular tools and investigated concerning their antimicrobial activity against different human pathogenic bacteria. Thirty-seven out of 39 CBMAI strains investigated were identified to at least at genus level by ITS and rDNA D1\\/D2
L. D. Sette; M. R. Z. Passarini; C. Delarmelina; F. Salati; M. C. T. Duarte
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
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
The susceptibilities to antimicrobialagents of and distributions of antiseptic resistance genes in methicillin- resistant Staphylococcus aureus (MRSA) strains isolated between 1999 and 2004 in Japan were examined. The data of MRSA strains that are causative agents of impetigo and staphylococcal scalded skin syndrome (SSSS) were compared with those of MRSA strains isolated from patients with other diseases. The susceptibilities
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 antimicrobialagents 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 antimicrobialagents 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.
Aarestrup, Frank M?ller; Seyfarth, Anne Mette; Emborg, Hanne-Dorthe; Pedersen, Karl; Hendriksen, Rene S.; Bager, Flemming
The incidence and severity of Clostridium difficile-associated disease (CDAD) is increasing, and standard treatment is not always effective. Therefore, more-effective antimicrobialagents and treatment strategies are needed. We used the agar dilution method to determine the in vitro susceptibility of the following antimicrobials against 110 toxigenic clinical isolates of C. difficile from 1983 to 2004, primarily from the United States: doripenem, meropenem, gatifloxacin, levofloxacin, moxifloxacin, OPT-80, ramoplanin, rifalazil, rifaximin, nitazoxanide, tizoxanide, tigecycline, vancomycin, tinidazole, and metronidazole. Included among the isolates tested were six strains of the toxinotype III, NAP1/BI/027 group implicated in recent U.S., Canadian, and European outbreaks. The most active agents in vitro were rifaximin, rifalazil, tizoxanide, nitazoxanide, and OPT-80 with MICs at which 50% of the isolates are inhibited (MIC50) and MIC90 values of 0.0075 and 0.015 ?g/ml, 0.0075 and 0.03 ?g/ml, 0.06 and 0.125 ?g/ml, 0.06 and 0.125 ?g/ml, 0.125 and 0.125 ?g/ml, respectively. However, for three isolates the rifalazil and rifaximin MICs were very high (MIC of >256 ?g/ml). Ramoplanin, vancomycin, doripenem, and meropenem were also very active in vitro with narrow MIC50 and MIC90 ranges. None of the isolates were resistant to metronidazole, the only agent for which there are breakpoints, with tinidazole showing nearly identical results. These in vitro susceptibility results are encouraging and support continued evaluation of selected antimicrobials in clinical trials of treatment for CDAD.
Hecht, David W.; Galang, Minerva A.; Sambol, Susan P.; Osmolski, James R.; Johnson, Stuart; Gerding, Dale N.
Sixteen antimicrobialagents were tested for their activity against 68 isolates of Actinobacillus pleuropneumoniae by determining the minimum inhibitory concentrations (MICs). Ceftiofur and the fluoroquinolones danofloxacin and enrofloxacin were the most active compounds, with a MIC for 90% of the isolates (MIC90) of (0.05 microg/ml. The MIC90 values of benzylpenicillin, amoxicillin and aspoxicillin were 0.78 units/ml, 0.39 microg/ml and < or = 0.05 microg/ml, respectively. Three isolates (4.4%) were resistant to penicillins, but aspoxicillin was as active as ceftiofur against the susceptible isolates, with MICs of < or = 0.05 microg/ml for all isolates. Resistance to oxytetracycline, chloramphenicol and thiamphenicol occurred in 22 (32.4%), 14 (20.6%) and 15 (22.1%) of the isolates, respectively. Doxycycline was more active than oxytetracycline, with a MIC90 of 1.56 microg/ml as against 25 microg/ml. Florfenicol was not only as active as thiamphenicol, with a MIC for 50% of the isolates (MIC50) of 0.39 microg/ml, but also active against thiamphenicol-resistant isolates. All the isolates were susceptible to florfenicol. All the isolates were also susceptible to gentamicin, spectinomycin, tilmicosin, colistin and tiamulin. Of these, spectinomycin was the least active, with a MIC50 of 25 microg/ml, followed by tiamulin, with a MIC50 of 6.25 microg/ml. Of the 68 isolates tested, 49 (72.0%) were of serotype 2; 14 (20.5%) were of serotype 1; 2 each (3.0%) were of serotypes 5 and 6; and one was of serotype 7. Of the isolates, 23 (33.8%) were resistant to one or more of the major antibiotics. Antibiotic resistance was found only infrequently among serotype 2, with 5 (10.2%) of 49 isolates being resistant to chloramphenicol and/or oxytetracycline, while it occurred in 18 (94.7%) of the 19 isolates of other serotypes. PMID:11860083
The Upjohn oxazolidinones, U-100592 and U-100766, are orally bioavailable synthetic antimicrobialagents with spectra of activity against antibiotic-susceptible and -resistant gram-positive pathogens. In several mouse models of methicillin-resistant Staphylococcus aureus infection, U-100592 and U-100766 yielded oral 50% effectivedoses(ED50)rangingfrom1.9to8.0mg\\/kgofbodyweight,whichcomparedfavorablywithvancomycin subcutaneous ED50values of 1.1 to 4.4 mg\\/kg. Similarly, both compounds were active versus aStaphylococcus epidermidisexperimental systemic infection. U-100592 and U-100766 effectively cured
CHARLES W. FORD; JUDITH C. HAMEL; DEBBIE M. WILSON; JUDY K. MOERMAN; DOUGLAS STAPERT; ROBERT J. YANCEY; DOUGLAS K. HUTCHINSON; MICHAEL R. BARBACHYN; ANDSTEVEN J. BRICKNER
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
Lai Wah Chan; Emily LC Cheah; Constance LL Saw; Wanyu Weng; Paul WS Heng
The antibacterial activities of the alcohol, ethyl acetate, acetone and chloroform extracts of 5 plant species were studied. The extracts of Pimpinella anisum (L.) (anise, aniseed) (seed), Coriandrum sativum (L.) (coriander, cilantro) (seed), Glycyrrhiza glabra (L.) (liquorice) (root), Cinnamomum cassia Blume (cassia bark, Chinese cinnamon) (bark), and Juniperus oxycedrus (L.) (juniper) (seed) were tested in vitro against 13 bacterial species
Ixodes scapularis transmits the agent of human granulocytic anaplasmosis, among other pathogens. The mechanisms used by the tick to control Anaplasma phagocytophilum are not known. We demonstrate that the I. scapularis Janus kinase (JAK)–signaling transducer activator of transcription (STAT) pathway plays a critical role in A. phagocytophilum infection of ticks. The A. phagocytophilum burden increases in salivary glands and hemolymph when the JAK-STAT pathway is suppressed by RNA interference. The JAK-STAT pathway exerts its anti-Anaplasma activity presumably through STAT-regulated effectors. A salivary gland gene family encoding 5.3-kDa antimicrobial peptides is highly induced upon A. phagocytophilum infection of tick salivary glands. Gene expression and electrophoretic mobility shift assays showed that the 5.3-kDa antimicrobial peptide–encoding genes are regulated by tick STAT. Silencing of these genes increased A. phagocytophilum infection of tick salivary glands and transmission to mammalian host. These data suggest that the JAK-STAT signaling pathway plays a key role in controlling A. phagocytophilum infection in ticks by regulating the expression of antimicrobial peptides.
Edema disease (ED) of pigs is an enterotoxaemic disease caused by enterotoxaemic Escherichia coli (ETEEC) infection. Antimicrobial therapy for pigs with ED is controversial because it may induce death of sickish piglets. In this study, we investigated the effects in vitro of 7 antimicrobialagents, ampicillin, gentamicin, colistin, bicozamycin, fosfomycin, sulfamethoxazole-trimethoprim and enrofloxacin, on the release and production of shiga toxin (Stx) 2e by ETEEC strains. We found that more Stx 2e accumulated in the bacterial cells than was released into supernatant. Associated with inhibition of cell wall synthesis, the exposure to ampicillin or fosfomycin increased the release of Stx 2e. The production levels of Stx 2e in all antimicrobial-treated cultures were equal to the level in the control or less than in the control. These results suggest that cell wall synthesis inhibitors, such as ampicillin and fosfomycin, may change for the worse in the signs in ETEEC infectious pigs. On the other hand, gentamicin, colistin, bicozamycin and enrofloxacin may be useful for the treatment of pigs with ED. PMID:15353838
Selecting proper cleaning and sanitizing agents is an important first step toward a good sanitation program for your processing plant. Your choice is complicated by the sheer number of products available and by myriad claims of superiority. To make a prop...
This paper proposes the feedback control agents (FBCAs) of the multiagent power plant control system. The FBCAs are capable of flexible autonomous action in the environment in order to meet their design objectives. The FBCAs make decision using genetic algorithm based fuzzy control. The simulation results show that the genetic algorithm based fuzzy control is an effective tool for the
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 antimicrobialagents 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
Hydrazide/hydrazone derivatives are of quite interest for medicinal chemists because of their vast spectrum of biological activity. Literature reports reveal that the hydrazide derivatives have been extensively studied for their biological profile during the past decade. The aim of the present work is to collect literature reports focusing the antimicrobial and anticancer study of different hydrazide/hydrazone derivatives carried out during the past decade which will serve as a valuable source of information for the researchers working in the field of antimicrobial and anticancer research. PMID:23621636
Hydrazide/hydrazone derivatives are of quite interest for medicinal chemists because of their vast spectrum of biological activity. Literature reports reveal that the hydrazide derivatives have been extensively studied for their biological profile during the past decade. The aim of the present work is to collect literature reports focusing the antimicrobial and anticancer study of different hydrazide/hydrazone derivatives carried out during the past decade which will serve as a valuable source of information for the researchers working in the field of antimicrobial and anticancer research. PMID:23621689
The antimicrobial activities of 10 plant species (Voacanga africana, Crepis cameroonica, Plagiostyles africana, Crotalaria retusa, Mammea africana, Lophira lanceolata, Ochna afzelii, Ouratea elongata, Ou. flava and Ou. sulcata), each of which is currently used in the traditional medicine of Cameroon, were investigated in vitro. The activities of a methanol extract of each plant were tested, in disc-diffusion assays, against 37 reference or laboratory strains of seven species of microorganism (Staphylococcus aureus, S. epidermidis, Enterococcus hirae, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Candida albicans). The minimal inhibitory concentrations of each extract were then estimated, against each of the more susceptible microorganisms (i.e. those giving an inhibition zone measuring at least 9 mm in diameter in the disc-diffusion assays), by agar dilution. Although, in the disc-diffusion assays, each of the 10 methanol extracts investigated displayed some degree of antimicrobial activity against at least one species of microorganism, no activity against the Gram-negative bacteria (Es. coli, K. pneumoniae and Ps. aeruginosa) was observed. The extract with the greatest antimicrobial activity was that of Pl. africana (Euphorbiaceae). PMID:16630381
Gangoué-Piéboji, J; Pegnyemb, D E; Niyitegeka, D; Nsangou, A; Eze, N; Minyem, C; Mbing, J Ngo; Ngassam, P; Tih, R Ghogomu; Sodengam, B L; Bodo, B
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.
Chan, Lai Wah; Cheah, Emily LC; Saw, Constance LL; Weng, Wanyu; Heng, Paul WS
The purpose of this study was to determine the activities of two antibacterial agents used in the treatment of bovine respiratory infections-tulathromycin, a macrolide, and ceftiofur, a third-generation cephalosporin-alone, in combination with each other, and in combination with each of seven additional antibiotics (tilmicosin, florfenicol, enrofloxacin, danofloxacin, ampicillin, tetracycline, and penicillin G) against bovine Pasteurella multocida (n = 60) and Mannheimia haemolytica (n = 10) isolates for determination of synergy, antagonism, or indifference. Of 458 organism-drug combinations, 160 combinations of tulathromycin and 209 combinations of ceftiofur with eight antimicrobial drugs were indifferent. One combination was antagonistic (ceftiofur + florfenicol against one isolate of P. multocida). Time-kill studies showed loss of cidality for ceftiofur when combined with florfenicol at 1x the minimal inhibitory concentration. Overall, the in vitro data demonstrated that tulathromycin and ceftiofur, in combination with each other or seven other antimicrobialagents, primarily produce an indifferent response with no occurrences of synergism and rare occurrences of antagonism. PMID:19003782
Sweeney, Michael T; Brumbaugh, Gordon W; Watts, Jeffrey L
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 antimicrobialagents (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 antimicrobialagents. 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.
Well-crystalline ZnO nanoflowers were prepared by a facile solution process and their applications as an antimicrobialagent against Escherichia coli and enzyme-free glucose sensor have been studied. The morphological, structural, compositional, and optical properties of ZnO nanoflowers were characterized by various techniques, which confirmed the well-crystalline wurtzite hexagonal phase. The minimum inhibitory concentration of ZnO nanoflowers for inhibiting the growth of Escherichia coli was found to be 25 microg/ml. ZnO nanoflowers were also tested as an efficient electron mediator for the fabrication of highly sensitive non-enzymatic glucose sensor, which exhibited a high sensitivity of -411 microA M(-1) cm(-2) and detection limit of -1.25 mM with a quick response time of -10.0 s. The presented studies showed that ZnO nanomaterials can be efficiently used as an antimicrobialagent and a highly sensitive non-enzymatic glucose sensor. PMID:24015509
There is an urgent need for new antimicrobialagents to combat infections caused by drug-resistant pathogens. Once a compound is shown to be effective in vitro, it is necessary to evaluate its efficacy in an animal infection model. Typically, this is achieved using a mammalian model, but such experiments are costly, time consuming, and require full ethical consideration. Hence, cheaper and ethically more acceptable invertebrate models of infection have been introduced, including the larvae of the greater wax moth Galleria mellonella. Invertebrates have an immune system that is functionally similar to the innate immune system of mammals, and often identical virulence and pathogenicity factors are used by human pathogenic microbes to infect wax moth larvae and mammals. Moreover, the virulence of many human pathogens is comparable in wax moth larvae and mammals. Using key examples from the literature, this chapter highlights the benefits of using the wax moth larva model to provide a rapid, inexpensive, and reliable evaluation of the toxicity and efficacy of new antimicrobialagents in vivo and prior to the use of more expensive mammalian models. This simple insect model can bridge the gap between in vitro studies and mammalian experimentation by screening out compounds with a low likelihood of success, while providing greater justification for further studies in mammalian systems. Thus, broader implementation of the wax moth larva model into anti-infective drug discovery and development programs could reduce the use of mammals during preclinical assessments and the overall cost of drug development. PMID:22305092
Several novel 6-aryl-5-cyano thiouracil derivatives were synthesized and explored for their activities as antibacterial, antifungal and anticancer agents. The antimicrobial evaluation revealed that compounds 7b and 7c possessed superior antibacterial activity against the Gram positive bacteria S. aureus and B. subtilis compared to the reference drug amoxicillin. Moreover, compound 4i was found to be a broad spectrum antimicrobialagent and it also exhibited the highest antifungal activity against C. albicans, even higher than the reference drug amphotericin B (MIC = 2.34, 3.00 ?g/mL respectively). Selected compounds were tested for in vitro cytotoxicity at a single 10(-5) M concentration in accordance to the NCI (USA) protocol. The preliminary screening results showed that most of the compounds had limited cytotoxic activity against renal cancer UO-31 and/or A498 cell lines. Nevertheless, compounds 6d and 6i displayed potent growth inhibitory effect toward non-small cell lung cancer HOP-92 and leukemia MOLT-4 cell lines, respectively. PMID:22902882
Widely used antimicrobial volatile organic compounds, such as sulphur dioxide and ethanol but also selected aroma compounds such as carvacrol, allyl isothiocyanate (AITC) and cinnamaldehyde, were tested single and in binary combination for their effect on Penicillium notatum growth in vapour phase at 30 °C. Aroma compounds were more efficient compared to sulphur dioxide and ethanol. AITC and cinnamaldehyde had the
S. Tunc; E. Chollet; P. Chalier; L. Preziosi-Belloy; N. Gontard
A new category of amphiphilic hydrolyzable quaternary ammonium compounds with rapid and high levels of antimicrobial activity was studied. The compounds, alkanoylcholines with hydrocarbon chains of 10 to 14 carbon atoms, are hydrolyzed by butyrylcholine esterase, which is present in human serum and mucosal membranes. The hydrolysis products are common components of human metabolism. Alkanoylcholines were tested and found to
BRITTA AHLSTROM; MONIKA CHELMINSKA-BERTILSSON; RICHARD A. THOMPSON; ANDLARS EDEBO
Statement of problem. Antimicrobial mouthrinses have become an important part of comprehensive dental care. However, mouthrinses that contain alcohol have been shown to be detrimental to patients undergoing radiation therapy for head and neck cancer, to some immunocompromised patients, to families with small children, and to persons sensitive to alcohol. Purpose. This study evaluated the effectiveness of alcohol-free, 0.12% chlorhexidine
Kathrine R. Eldridge; Sonja F. Finnie; Joni A. Stephens; Amable M. Mauad; Carlos A. Munoz; James D. Kettering
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
The agar dilution method was used to determine the inhibitory activity of 25 antimicrobialagents against 69 strains of Dichelobacter nodosus and 108 strains of the genus Fusobacterium, all of which were isolated from 90 clinical cases of ovine footrot between October 1998 and November 2000. In the case of the micro-organisms belonging to the genus Fusobacterium, the six beta-lactams studied (benzyl penicillin, ampicillin, cloxacillin, cefadroxil, cefuroxime and cephalexine) proved to be, in general, the most effective antimicrobialagents. Chloramphenicol, clindamycin and doxycycline were also quite active against Fusobacterium spp. With regard to the 69 strains of D. nodosus tested, the levels of resistance remain low. PMID:15330985
Antimicrobial resistance of enterococci was investigated in 42 samples of crude inflow, treated effluent and sludge collected in 14 municipal sewage treatment plants of Portugal. A total of 983 enterococci were recovered and tested, using the diffusion agar method, regarding their sensitivity to 10 different antimicrobial drugs. Multidrug resistance was present in 49.4% of the isolates. Only 3.3% and 0.6%
Paulo Martins da Costa; Paulo Vaz-Pires; Fernando Bernardo
A yeast cDNA expression library was screened to identify genes and cellular processes that influence fungal sensitivity to a plantantimicrobial peptide. A plasmid-based, GAL1 promoter-driven yeast cDNA expression library was introduced into a yeast genotype susceptible to the antimicrobial peptide MiAMP1 purified from Macadamia integrifolia. Following a screen of 20,000 cDNAs, three yeast cDNAs were identified that reproducibly provided
Camilla Stephens; Stuart J. Harrison; Kemal Kazan; Frank W. N. Smith; Ken C. Goulter; Donald J. Maclean; John M. Manners
The wide range of naturally occurring compounds from microorganisms and plants which are phototoxic in UV-A light (320-400 nm) includes cinnamyl esters, coumarins and furanocoumarins, furanochromones, benzofurans, alkaloids, based on tryptophan or phenylalanine, extended naptho-and anthraquinones, polyacetylenes and their thiophene derivatives. The cellular targets are cell membranes, e.g., acetylenes, or the nucleus, e.g., furanocoumarins. Compounds reacting with cell membranes in light either generate singlet oxygen, e.g., alpha-terthienyl, or react by a free radical mechanism, e.g., phenylheptatriyne, or do both. Those that react with nucleic acids intercalate with these macromolecules forming photoadducts, e.g., furanocoumarins, furanochromones and furanoquinolines. With others, such as the beta-carbolines, the explanation for their photogenotoxicity is unknown. A number of these natural photosensitizers have been examined with bacteria, yeasts, and viruses and the mechanisms of phototoxicity have been elucidated. Some of the sulfur-containing acetylenes may be useful in photochemotherapy. PMID:3615635
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
Two vanillin derivatives have been designed and synthesized and their biological activities were also evaluated for antimicrobial activity. Their chemical structures are characterized by single crystal X-ray diffraction studies, 1H NMR, MS, and elemental analysis. Structural stabilization of them followed by intramolecular as well as intermolecular H-bonds makes these molecules as perfect examples in molecular recognition with self-complementary donor and acceptor units within a single molecule. Docking simulations have been performed to position compounds into the FtsZ active site to determine their probable binding model. Compound 3a shows the most potent biological activity, which may be a promising antimicrobial leading compound for the further research.
The aim of this study is to investigate chemical composition of acetone extracts of the lichens Evernia prunastri and Pseudoevernia furfuraceae and in vitro antioxidant, antimicrobial, and anticancer activities of these extracts and some their major metabolites. HPLC-UV method was used for identification of secondary metabolites. Antioxidant activity was evaluated by free radical scavenging, superoxide anion radical scavenging, reducing power and determination of total phenolic compounds. As a result of the study physodic acid had largest antioxidant activities. Total content of phenol in extracts was determined as pyrocatechol equivalent. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method. The most active was also physodic acid. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using MTT method. PMID:23220145
The mechanisms by which bacteria resist killing by antibiotics and biocides are still poorly defined, although repeated exposure to sublethal concentrations of antibacterial agents undoubtedly contributes to their development. This study aimed both to investigate the potential of Salmonella enterica and Escherichia coli O157 for adaptive resistance to commonly used biocides and to determine any cross-resistance to antibiotics. Strains were repeatedly passaged in media containing increasing concentrations of a biocide or antibiotic until adaptive resistance was obtained. A wide panel of antimicrobialagents was then screened by using the adapted strain to determine cross-resistance, if any. Adaptive resistance was readily achieved for both S. enterica and E. coli O157. Cross-resistance in adaptively resistant S. enterica varied with the serotype; Salmonella enterica serovar Enteritidis expressed cross-resistance to chloramphenicol, whereas Salmonella enterica serovar Typhimurium expressed cross-resistance to chlorhexidine. Benzalkonium chloride-resistant Salmonella enterica serovar Virchow showed elevated resistance to chlorhexidine; however, chlorhexidine-resistant Salmonella serovar Virchow did not demonstrate reciprocal cross-resistance to benzalkonium chloride, suggesting specific rather than generic resistance mechanisms. E. coli O157 strains acquired high levels of resistance to triclosan after only two sublethal exposures and, when adapted, repeatedly demonstrated decreased susceptibilities to various antimicrobialagents, including chloramphenicol, erythromycin, imipenem, tetracycline, and trimethoprim, as well as to a number of biocides. These observations raise concern over the indiscriminate and often inappropriate use of biocides, especially triclosan, in situations where they are unnecessary, whereby they may contribute to the development of microbial resistance mechanisms. PMID:14715734
Plant-derived phenylpropanoids (PPPs) compose the largest group of secondary metabolites produced by higher plants, mainly, for the protection against biotic or abiotic stresses such as infections, wounding, UV irradiation, exposure to ozone, pollutants, and herbivores. PPPs are parent molecules for biosynthesis of numerous structurally and functionally diverse plant polyphenols (simple phenolic acids and esters, glycosylated derivatives of primary PPPs, flavonoids, isoflavonoids, stilbenes, coumarins, curcuminoids, lignans, etc.), which play multiple essential roles in plant physiology. During the last few decades, extensive research has been dedicated to natural and biotechnologically produced PPPs for medicinal use as antioxidants, UV screens, anticancer, antiviral, anti-inflammatory, wound healing, and antibacterial agents. In the present review, the metabolic pathways of phenylpropanoid biosynthesis in plants and their re-construction in biotechnologically engineered systems are described. Chemical physical peculiarities of PPPs defining their antioxidant, metal chelating, and UV-protecting effects as a molecular basis for their anti-inflammatory properties are discussed as well. We focused also on the discovery of PPPs-based anti-inflammatory agents since distinct PPPs were found to modulate molecular pathways underlying inflammatory responses in human cells triggered by different pro-inflammatory stimuli in vitro and to inhibit inflammation in various tissues in vivo. The problem of low bioavailability, fast metabolism, and potential toxicity/sensitization as limiting factors for the development of PPPs-based anti-inflammatory drugs is also highlighted. PMID:21762105
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
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
The sponge-associated actinomycetes were isolated from the marine sponge Dendrilla nigra, collected from the southwest coast of India. Eleven actinomycetes were isolated depending upon the heterogeneity and stability\\u000a in subculturing. Among these, Nocardiopsis dassonvillei MAD08 showed 100% activity against the multidrug resistant pathogens tested. The culture conditions of N. dassonvillei MAD08 was optimized under submerged fermentation conditions for enhanced antimicrobial
Joseph Selvin; S. Shanmughapriya; R. Gandhimathi; G. Seghal Kiran; T. Rajeetha Ravji; K. Natarajaseenivasan; T. A. Hema
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 (ED(50)) 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
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
Radiosensitivities of methyl, ethyl, propyl and butyl parabens and sodium salts of methyl and propyl parabens (hereafter, MP, EP, PP, BP, SMP and SPP, respectively) were investigated by monitoring, through electron spin resonance (ESR) spectroscopy, the evolution under different experimental conditions of characteristic features of the radicalic species produced upon irradiation by gamma radiation. While ESR spectra of the studied parabens consisted of the sum of broad and narrow resonance lines of different microwave saturation and thermal characteristics, those of sodium salts appeared to consist of the sum of two overlapping narrow resonance lines. Radical species presented different room and high-temperature decay characteristics, depending on the extent of the cage effect created by the lattice networks on these species. A model based on the presence of two radical species presenting different spectroscopic and kinetic features described best the experimental data collected for parabens and their sodium salts. Radiation yields of the studied parabens towards gamma radiation were calculated to be low (G?10-2), providing the opportunity of using these antimicrobialagents in food, cosmetics and drugs to be sterilized by radiation without much loss from their antimicrobial activities.
The present study was undertaken with the aim of finding an alternative preservative system to methyl parahydroxybenzoate in zinc gelatin, which was described in the monographs of the Swiss Pharmacopoeia (until Ph. Helv. 8) and in previous editions of the German Pharmacopoeia (until DAB 7). This antimicrobialagent has now been withdrawn in the DAB, because of its potential allergy risks. As for the USP and DAB-DDR zinc gelatin preparations, they have always been devoid of any preservative agent, probably relying on the mild antimicrobial activity of zinc. A literature survey did not reveal if such an aqueous preparation containing the water-insoluble zinc oxide shows efficacious antimicrobial activity by itself. Thus, a comparative evaluation of differently preserved zinc gelatin preparations was performed using a test for the efficacy of antimicrobial preservation that has been modified with regard to the European Pharmacopoeia (EP) test to take into account the solid state of the preparations and the bactericidal effect of the zinc. Three zinc gelatin preparations were checked, either: (i), without any agent; or (ii), with 0.1% methyl parahydroxybenzoate; or (iii), with 0.5% phenoxyethanol, a broad-spectrum antimicrobialagent almost devoid of allergy risks. The three preparations behave quite differently, in particular with respect to fungi. All three preparations passed the modified EP test as far as bacteria are concerned. Even zinc gelatin without preservative is very effective, not only because of the mild antimicrobial activity of zinc (the soluble fraction of zinc oxide in the liquid phase of zinc gelatin was determined to be 13 microg/ml), but most probably because of the low water activity of the preparation (measured as around 0.81), as shown by the absence of growth of a zinc-resistant strain of Pseudomonas aeruginosa. Zinc gelatin preserved with methyl parahydroxybenzoate has a weak, although satisfactory, activity against Staphylococcus aureus. Regarding fungi, gelatin without an antimicrobialagent and that preserved with methyl parahydroxybenzoate meet the requirements for efficacy against Candida albicans, but are only bacteriostatic against Aspergillus niger. As for zinc gelatin preserved with phenoxyethanol, it displays the best activity against C. albicans and, above all, appears to be the only formulation exhibiting fungicidal activity against A. niger. It is therefore recommended to preserve zinc gelatin with this antimicrobialagent, as recently adopted in Supplement 2000 of the Swiss Pharmacopoeia. PMID:11522494
Incorporating antimicrobial compounds into edible films or coatings provides a novel way to improve the safety and shelf life of ready-to-eat foods. Diverse studies with Quillaja saponaria Mol. (popularly named quillay) extracts have demonstrated their potential as antifungal agents against phytopathogenic fungi. Crosslinking induced by ionizing radiation is an effective method for the improvement of both barrier and mechanical properties
G. E. Zúńiga; M. P. Junqueira-Gonçalves; M. Pizarro; R. Contreras; A. Tapia; S. Silva
Edible coatings with antimicrobialagents can extend the shelf-life of fresh-cut fruit. The effect of lemongrass, oregano oil and vanillin incorporated in apple puree-alginate edible coatings, on the shelf-life of fresh-cut Fuji apples, was investigated. Coated apples were packed in air-filled pol...
The present study was undertaken with the aim of finding an alternative preservative system to methyl parahydroxybenzoate in zinc gelatin, which was described in the monographs of the Swiss Pharmacopoeia (until Ph. Helv. 8) and in previous editions of the German Pharmacopoeia (until DAB 7). This antimicrobialagent has now been withdrawn in the DAB, because of its potential allergy
Jocelyne Favet; Marie-Louise Chappuis; Eric Doelker
It has been shown that the inappropriate use of antimicrobial household agents selects for organisms with resistance mechanisms (e.g. efflux pumps), which could lead to the development of antibiotic resistance. The reverse hypothesis, that antibiotic-resistant organisms become tolerant to other antibacterial agents (e.g. disinfectants) due to the action of efflux pumps, has however not been extensively examined. The objective of
C. A. Thorrold; M. E. Letsoalo; A. G. Dusé; E. Marais
Campylobacter jejuni has recently been noted as the most common cause of bacterial food-borne diseases in Japan. In this study, we examined in\\u000a vitro susceptibility to 36 antimicrobialagents 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\\u000a (imipenem, meropenem, panipenem, and
Libraries of 1-methyl-2,4-diaryl-3-azabicyclo[3.3.1]nonan-9-ones\\/oximes\\/O-methyloximes 1–14\\/15–28\\/29–42 and 7-methyl-2,4-diaryl-3-azabicyclo[3.3.1]nonan-9-ones\\/oximes\\/O-methyloximes 43–48\\/49–54\\/55–60 were synthesized and their stereochemistry was established by 1D\\/2D NMR spectral and single crystal XRD studies. All the synthesized oximes and oxime ethers were screened for their in vitro antimicrobial activity against a panel of pathogenic bacteria (Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa) and fungi (Candida albicans, Candida parapsilosis, Aspergillus
Paramasivam Parthiban; Paramasivam Rathika; Venkatachalam Ramkumar; Se Mo Son; Yeon Tae Jeong
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
The lipid composition of Prototheca wickerhamii ATCC 16529 is presented and discussed in relation to the unique susceptibility of the organism to drugs of three membrane-active antimicrobial classes: the polyenes, the polymyxins, and the imidazoles. The presence of ergosterol in the neutral lipid fraction of the membrane is likely responsible for the exquisite susceptibility to amphotericin B. The presence of a large quantity of free fatty acids in the membrane appears responsible for imidazole susceptibility. The membrane determinants of polymyxin B susceptibility are less well defined.
In an effort to establish new candidates with improved antineoplastic, anti-HIV-1 and antimicrobial activities we report here the synthesis and in vitro biological evaluation of various series of 2-substituted benzoxazoles: 2-[(Arylhydrazono, arylidene, cycloalkylidene and N-substituted thiocarbamoyl)cyanomethyl]-benzoxazoles(2–4 and 7, respectively); 2-[(4- or 5-oxothiazoliden-2-yliden)benzoxazoles (5 and 6) and 2-(4-amino-3-substituted-2-thioxo-2,3-dihydrothiazol-5-yl)benzoxazoles (8), together with the synthesis of some substituted 3H-pyrido[2,1-b]benzoxazoles (9–11). The absolute configuration
Samia M. Rida; Fawzia A. Ashour; Soad A. M. El-Hawash; Mona M. ElSemary; Mona H. Badr; Manal A. Shalaby
A series of quinoxalinone derivatives was synthesized by the condensation of 1,2-diaminobenzene with alpha-ketoglutaric acid to yield 3-(3-oxo-3,4-dihydroquinoxalin-2-yl) propionic acid (2) and then treated with hydrazine hydrate to yield its hydrazones (3). This was further reacted with substituted aromatic aldehydes to produce final compounds (4a-r). These hydrazones derivatives were characterized by FT-IR and 1H-NMR data. All the synthesized compounds were evaluated for their antimicrobial and antiinflammatory activity. PMID:19719051
Khan, Suroor A; Mullick, Pooja; Pandit, Shabir; Kaushik, Darpan
One of the greatest challenges facing modern medicine is the evolution of drug resistant strains of bacteria. In addition to traditional methods of exposure to traditional bacterial organisms there is a growing concerned of the use of bacteria as bio-terrorism agents. To counter the evolution of drug resistant and potential bio-terrorism bacterial agents new antibiotic drugs must be developed. One
Divakaramenon Venugopal; David Klapper; Antoine H. Srouji; Jayendra B. Bhonsle; Richard Borschel; Allen Mueller; Amanda L. Russell; Brittany C. Williams; Rickey P. Hicks
The objective of this chapter is to present fundamental factors (e.g. intrinsic and extrinsic) influencing chitosan as antimicrobialagent, for effective practical application. The antimicrobial activity of chitosan is well observed on a wide variety of micro-organisms including fungi, algae and some bacteria. However, the antimicrobial action is influenced by intrinsic and extrinsic factors such as the type of chitosan (e.g. plain or derivative); degree of chitosan polymerization; host natural nutrient constituency; substrate chemical and/or nutrient composition; and environmental conditions (e.g. substrate water activity (Aw) and/or moisture). Although both plain and derivative chitosans are effective as antimicrobialagents, there is a differential effect between them. Their differential antimicrobial effect is mainly exhibited in live host plants; thus the antifungal effect of N-carboxymethyl chitosan (NCMC) is different in vegetable as compared with graminea host. At the same time, pentamer and heptamer chitosan units seem to have better antifungal action than larger units. Chitosan antimicrobial action is more immediate on fungi and algae, followed by bacteria; the chitosan site of action is at the microbial cell wall. PMID:10906970
The traditional medicine still plays an important role in the primary health care in Yemen. The current study represents the investigation of 16 selected plants, which were collected from different localities of Yemen. The plants were dried and extracted with two different solvents (methanol and hot water) to yield 34 crude extracts. The obtained extracts were tested for their antimicrobial activity against three Gram-positive bacteria, two Gram-negative bacteria, one yeast species and three multiresistant Staphylococcus strains using agar diffusion method, for their antioxidant activity using scavenging activity of DPPH radical method and for their cytotoxic activity using the neutral red uptake assay. In addition, a phytochemical screening of the methanolic extracts was done. Antibacterial activity was shown only against Gram-positive bacteria, among them multiresistant bacteria. The highest antimicrobial activity was exhibited by the methanolic extracts of Acalypha fruticosa, Centaurea pseudosinaica, Dodonaea viscosa, Jatropha variegata, Lippia citriodora, Plectranthus hadiensis, Tragia pungens and Verbascum bottae. Six methanolic extracts especially those of A. fruticosa, Actiniopteris semiflabellata, D. viscosa, P. hadiensis, T. pungens and V. bottae showed high free radical scavenging activity. Moreover, remarkable cytotoxic activity against FL-cells was found for the methanolic extracts of A. fruticosa, Iris albicans, L. citriodora and T. pungens. The phytochemical screening demonstrated the presence of different types of compounds like flavonoids, terpenoids and others, which could be responsible for the obtained activities.
Abdo, Salah A. A.; Hasson, Sidgi; Althawab, Faisal M. N.; Alaghbari, Sama A. Z.; Lindequist, Ulrike
It has been shown that the inappropriate use of antimicrobial household agents selects for organisms with resistance mechanisms (e.g. efflux pumps), which could lead to the development of antibiotic resistance. The reverse hypothesis, that antibiotic-resistant organisms become tolerant to other antibacterial agents (e.g. disinfectants) due to the action of efflux pumps, has however not been extensively examined. The objective of this study was to establish whether there is a link between antibiotic resistance in potential gastrointestinal pathogens and reduced sensitivity of these organisms to commonly used household antimicrobialagents. In this study, tetracycline and ofloxacin sensitive and resistant Escherichia coli (9 strains) and Salmonella spp. (8 strains) were isolated from poultry and clinical samples. In order to assess whether these bacteria had active efflux pumps, ethidium bromide accumulation assays were performed. Extrusion of the active components of three commercial household agents (triclosan, sodium salicylate, and ortho-phenylphenol) by efflux pumps was tested using spectrophotometric accumulation assays. In order to simulate the kitchen environment, in-use disinfectant testing using the commercial household agents was performed to determine changes in their efficacy due to antibiotic resistance. Active efflux pump activity and extrusion of all three active ingredients was observed only in the antibiotic resistant organisms. The antibiotic sensitive bacteria were also more susceptible than the resistant isolates to the household antimicrobialagents at concentrations below that recommended by the manufacturer. These resistant bacteria could potentially be selected for and result in hard to treat infections. PMID:17126442
Thorrold, C A; Letsoalo, M E; Dusé, A G; Marais, E
Clinical specimens from dogs, cats, and horses were examined for the presence of obligate anaerobic bacteria. Of 4,018 specimens cultured, 368 yielded 606 isolates of obligate anaerobic bacteria (248 from dogs, 50 from cats, and 308 from horses). There were 100 specimens from 94 animals from which only anaerobes were isolated (25 dogs, 8 cats, and 61 horses). The most common sites tested were abdominal fluid (dogs and cats) and intestinal contents (horses). The most common microorganism isolated from dogs, cats, and horses was Clostridium perfringens (75, 13, and101 isolates, respectively). The MICs of amoxicillin with clavulanate, ampicillin, chloramphenicol, metronidazole, and penicillin were determined using a gradient endpoint method for anaerobes. Isolates collected at necropsy were not tested for antimicrobial susceptibility unless so requested by the clinician. There were 1/145 isolates tested that were resistant to amoxicillin-clavulanate (resistance breakpoint ? 16/8 ?g/ml), 7/77 isolates tested were resistant to ampicillin (resistance breakpoint ? 2 ?g/ml), 4/242 isolates tested were resistant to chloramphenicol (resistance breakpoint ? 32 ?g/ml), 12/158 isolates tested were resistant to clindamycin (resistance breakpoint ? 8 ?g/ml), 10/247 isolates tested were resistant to metronidazole (resistance breakpoint ? 32 ?g/ml), and 54/243 isolates tested were resistant to penicillin (resistance breakpoint ? 2 ?g/ml). These data suggest that anaerobes are generally susceptible to antimicrobial drugs in vitro. PMID:24025899
C31G, an equimolar mixture of alkyl dimethyl glycine and alkyl dimethyl amine oxide, was evaluated for antimicrobial and antiadherence properties. The efficacy of C31G, its two components, and several commercial mouth rinses was determined in assays measuring inhibition of glycolysis, inhibition of bacterial adherence, and MICs. Inhibition of glycolysis was determined by using a saliva sediment model, with glycolytic activity expressed as the change in pH relative to that of a control. Adherence studies were undertaken with Streptococcus sobrinus 6715 to measure inhibition of adherence to nichrome wires. MICs were determined against selected microorganisms by standard methods. C31G demonstrated broad-spectrum antimicrobial properties, with activity against both gram-positive and gram-negative organisms and Candida albicans, a yeast. C31G inhibited both glycolysis by salivary bacteria and adherence of Streptococcus strains to wire mesh. C31G was more effective in the assays conducted than any commercial formulation tested and was as effective as chlorhexidine. A synergistic effect was demonstrated between the individual components of C31G, and no loss of activity was noted when it was formulated into a mouth rinse vehicle.
The hydroxypropionaldehyde (HPA) system is a natural defense system synthesized by the probiotic bacterium Lactobacillus reuteri. To elucidate which of the molecules composing the HPA system (3-hydroxypropionaldehyde (3-HPA), reuterin (HPA dimer), and HPA hydrate) is responsible for the potent antimicrobial activity in biological systems, a combination of biochemical, genetic, and proteomic assays was used. The HPA system reacts with sulfhydryl-containing compounds such as cysteine and reduced glutathione (GSH) in solution. In situ, GSH knock-out Escherichia coli is significantly more susceptible to HPA-mediated cell death than E. coli wild type; GSH supplementation protects either bacteria from HPA attack. Proteomic analysis of HPA-treated bacteria ( Haemophilus influenzae ) revealed induction of redox- and heat shock-related proteins. A new antimicrobial mechanism of HPA is proposed, whereby the activity of HPA leads to depletion of free SH- groups in GSH and proteins through the action of 3-hydroxypropionaldehyde, causing an imbalance of the cellular redox status, ultimately resulting in cell death. PMID:20845960
Sixty-three extracts obtained from 18 plants traditionally used in the South Pacific archipelago Vanuatu for the treatment of infectious diseases were screened for antimicrobial and antiprotozoal activities. In addition, the extracts were subjected to a detailed analysis on cytotoxic effects toward a panel of human cancer cell lines, designed as a smaller version of the NCI60 screen. Intriguingly, 15 plant extracts exhibited strong cytotoxic effects specific for only one cancer cell line. Extracts of the leaves of Acalypha grandis Benth. significantly affected Plasmodium falciparum without showing obvious effects against the other protozoa tested. The leaves of Gyrocarpus americanus Jacq. displayed significant activity against Trypanosoma b. brucei and the leaves of Tabernaemontana pandacaqui Lam. I as well as the stems of Macropiper latifolium (L.f.) against Trypanosoma cruzi. In contrast none of the extracts showed relevant antibacterial or antifungal activity. PMID:20014163
The antimicrobial activity of methanol and acetone extracts of Butomus umbellatus, Polygonum amphibium, and two species of the genus Sparganium (S. erectum and S. emersum)against three Gram-positive, five Gram-negative bacteria and one fungus was assessed by the disk diffusion method. The microorganisms used were Staphylococcus aureusATCC-29740, Escherichia coli ATCC-25922, Pseudomonas aeruginosa ATCC-15442, Salmonella typhi NCTC-9394, Klebsiella pneumoniae NCTC-5046, Proteus vulgaris ATCC-7829, Bacillus subtilis ATCC-6633, Corynebacterium diphteriae RSHM-633 and Candida albicans ATCC-10231. Methanol extracts of the plants did not exhibit any inhibitory activity against any of the microorganisms, while the acetone extracts of the all tested plants only showed significant activity against Bacillus subtilis, with inhibition zones and minimal inhibitory concentration values in the 7-16 mm and 0.49-12.50 mg/mL ranges, respectively. PMID:19145212
The susceptibilities of 11 strains representing the five recognized species of Legionella were determined by agar dilution testing on buffered charcoal-yeast extract agar. All of the legionellae tested were susceptible to rifampin, erythromycin, rosaramycin, chloramphenicol, and the aminoglycosides and were resistant to clindamycin and vancomycin. Susceptibilities to penicillins and cephalosporins were variable. Legionella micdadei, Legionella bozemanii, and Legionella gormanii were susceptible to these agents, but minimal inhibitory concentrations for each species were different. Legionella dumoffii resembled Legionella pneumophila in being resistant to penicillin, cephalothin, and cephamandole and susceptible to moxalactam and cefoxitin. All species except L. micdadei produced beta-lactamase. PMID:7325645
Pasculle, A W; Dowling, J N; Weyant, R S; Sniffen, J M; Cordes, L G; Gorman, G M; Feeley, J C
The susceptibilities of 11 strains representing the five recognized species of Legionella were determined by agar dilution testing on buffered charcoal-yeast extract agar. All of the legionellae tested were susceptible to rifampin, erythromycin, rosaramycin, chloramphenicol, and the aminoglycosides and were resistant to clindamycin and vancomycin. Susceptibilities to penicillins and cephalosporins were variable. Legionella micdadei, Legionella bozemanii, and Legionella gormanii were susceptible to these agents, but minimal inhibitory concentrations for each species were different. Legionella dumoffii resembled Legionella pneumophila in being resistant to penicillin, cephalothin, and cephamandole and susceptible to moxalactam and cefoxitin. All species except L. micdadei produced beta-lactamase.
Pasculle, A W; Dowling, J N; Weyant, R S; Sniffen, J M; Cordes, L G; Gorman, G M; Feeley, J C
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
We determined the in vitro antimycobacterial activity of rifampicin, isoniazid and a third agent in combination using a three-dimensional chequerboard in Middlebrook 7H9 broth microdilutions. Of 28 agents screened, ethambutol, streptomycin, clarithromycin, minocycline, ciprofloxacin, levofloxacin, sparfloxacin, gatifloxacin and sitafloxacin were potentially synergistic. A further three-dimensional chequerboard assay quantitatively looked for synergy against ten clinical isolates of Mycobacterium tuberculosis, including seven
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 antimicrobialagent, 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.
Khan A.K, Afzal; P.V, Mirshad; Rashed, Mohammed Rafiuddin; Banu, Gausia
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 antimicrobialagent, 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
A series of novel carbazole chalcones has been synthesised and evaluated for radical scavenging activity, cytotoxicity and antimicrobial activities. Compounds 12m, 12o and 12c exhibited good 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, compounds 12e, 12m and 12d were excellent hydroxyl radical scavengers and compounds 12a, 12e, 12g, 12n and 12m have shown inhibition of oxidative DNA damage induced by 2,2'-azobis (2-amidinopropane hydrochloride). Compounds 12j, 12i, 12n, 12c, 12m and 12e were most active against the selected cancer cell lines. Compounds 12a, 12e and 12m showed good antibacterial activity and compounds 12h and 12m have shown good antifungal activity. All the compounds were subjected for absorption, distribution, metabolism and excretion (ADME) predictions by computational method and found that these molecules could be considered as potential candidates for oral drug development. PMID:22380776
In vitro antibacterial activity tests of seven biofungicides (Ekstrasol, Bisolbisan, Bisolbifit, Serenade, Sonata, Timorex, F-Stop) and two disinfectants (colloidal silver alone and in combination with hydrogen peroxide) against the Pseudomonas tolaasii strain (NS3B6) were carried out by the disc-diffusion, broth microdilution and broth macrodilution method. Biofungicides tested in this study did not exhibit any antimicrobial activity in neither one of the methods used. Disc diffusion method revealed high sensitivity of the tested P. tolaasii strain to Ecocute based on colloidal silver and hydrogen peroxide. Both microdilution and macrodilution methods identified the same MICs and MBCs of Ecocute (0.19 mg/L) for P. tolaasii strain. MICs and MBCs values of silver alone were much higher (10 mg/L) compared to silver in combination with hydrogen peroxide. PMID:22375589
This article reviews the results and conclusions from four pivotal and two comparative clinical trials. The six randomized, controlled, single-blinded, parallel-group clinical trials were conducted to determine which antiseptic is best for use as a patient preoperative skin preparation. The objective of these studies was to compare the immediate, persistent (residual), and cumulative antimicrobial efficacy and safety of 2% chlorhexidine gluconate (CHG) combined with 70% isopropyl alcohol (IPA) (ChloraPrep); another combination CHG and IPA antiseptic (CHG+IPA) and 2% aqueous CHG alone; 4% CHG (Hibiclens) alone; 70% isopropyl alcohol (IPA) alone; and an iodine-containing solution, 10% povidone-iodine (Betadine) alone as preoperative skin topical antiseptics for potential prevention of nosocomial infections. PMID:15912075
A novel series of carbazole substituted aminopyrimidines (5a-p) were synthesized and screened for their in vitro urease inhibition and antimicrobial activity. Among the compounds, 4-(2,4-dichlorophenyl)-6-(9-methyl-9H-carbazol-3-yl)-pyrimidin-2-amine (5i) was found to be the most potent showing urease inhibitory activity with an IC(50) value 19.4?±?0.43 µM. Compounds 5c, 5g, 5j and 5o showed good activity against all selected bacterial strains and compounds 5b, 5c, 5m and 5o showed good activity against selected fungal strains. All the compounds were subjected for ADME predictions by computational method. PMID:23230954
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
3-Substituted benzylidene-1,3-dihydro-indoline derivatives were tested for their in vitro antibacterial activity against the Gram-negative bacteria Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and the Gram-positive bacteria Bacillus subtilis, Staphylococcus aureus, and for their their in vitro antifungal activity against Candida krusei and Candida albicans. The minimum inhibitory concentration (MIC) values were determined by the 2-fold serial dilution technique in Mueller Hinton broth and Sabouraud dextrose agar using antibacterial and antifungal assays, respectively. For comparison of the antimicrobial activity, rifampicin, ampicillin trihydrate, gentamicin sulfate, and ofloxacin were used as reference antibacterial agents, and fluconazole and amphotericin B were employed as reference antifungal agents. The most active compound 10 showed notable inhibition against Bacillus subtilis, Staphylococcus aureus, and Candida krusei. Compounds 1 and 6 were found slightly effective against Klebsiella pneumoniae and Escherichia coli. In addition, compounds 13 and 14 showed inhibition against Bacillus subtilis and Staphylococcus aureus. Indole derivatives were also tested in vitro for replication of the HepAD38 cell line and compared with lamivudine (3TC, L-2',3'-dideoxy-3'-thiacytidine). The IC50 values of the compounds were found to be >1000 microM against HBV except for compound 13 which exhibited activity with an IC50 value of 500 microM. PMID:19526705
We determined the in vitro antimycobacterial activity of rifampicin, isoniazid and a third agent in combination using a three-dimensional chequerboard in Middlebrook 7H9 broth microdilutions. Of 28 agents screened, ethambutol, streptomycin, clarithromycin, minocycline, ciprofloxacin, levofloxacin, sparfloxacin, gatifloxacin and sitafloxacin were potentially synergistic. A further three-dimensional chequerboard assay quantitatively looked for synergy against ten clinical isolates of Mycobacterium tuberculosis, including seven multidrug-resistant isolates. Sitafloxacin, gatifloxacin and clarithromycin showed significant synergy, with fractional inhibitory concentration indices ranging from 0.41 to 0.79, 0.39 to 0.90 and 0.48 to 0.95, respectively. It is concluded that three-dimensional chequerboard assay can quantitatively determine antimycobacterial synergy, and that fluoroquinolones and antibacterial agents such as clarithromycin are effective against multidrug-resistant isolates of M. tuberculosis when combined with rifampicin and isoniazid. PMID:16150578
The use of edible films as carriers of antimicrobialplant essential oils and other phytochemicals constitutes an approach for external protection of food systems to reduce surface microbial populations and to enhance oxygen-barrier properties, thus enhancing food safety as well as shelf life. The o...
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
Nontypeable Haemophilus influenzae (NTHi) makes the clinical course of acute otitis media (AOM) intractable by forming a biofilm that may hamper the clearance of the bacteria from middle ear cavity. In this study, we evaluated the minimum biofilm eradication concentration (MBEC) of antimicrobialagents against biofilm-forming NTHi strains. Twelve NTHi strains isolated from middle ear fluids of Japanese children with intractable AOM before antimicrobial treatment were evaluated for MBEC of fluoroquinolones in comparison with those of ?-lactams and macrolides. AMPC and CDTR required much higher concentration, i.e., high MBECs, to suppress the biofilm formation of NTHi. In contrast, fluoroquinolones followed by macrolides showed lower MBECs. MBEC would be a good parameter to infer the efficacies of antimicrobials against NTHi in biofilm. PMID:23549738
The primary objective of this study was to determine management practicesconcerning mastitisin Branden- burg, Germany, the prevalence of mastitis pathogens in dairy cows, and their resistance to selected antimi- crobial agents. A further objective was to study the potential effect of parity and stage of lactation on the resistance of Staphylococcus aureus isolates against ampicillin. Milk samples for microbiological culture
B.-A. Tenhagen; G. Köster; J. Wallmann; W. Heuwieser
DNA vaccines have been termed The Third Generation of Vaccines. The recent successful immunization of experimental animals against a range of infectious agents and several tumour models of disease with plasmid DNA testifies to the powerful nature of this revolutionary approach in vaccinology. Among numerous advantages, a major attraction of DNA vaccines over conventional vaccines is that they are able
Jason B. Alarcon; Gary W. Waine; Donald P. McManus
The responses of hypermutable Escherichia coli strains to selection with antibiotics having different endogenous resistance potentials were determined. Selections with rifampicin or cipro- floxacin at 4 × × × × MIC, i.e. conditions where they act as single target agents against RpoB and GyrA, respectively, demonstrated that some hypermutators generated resistant mutants with frequen- cies up to 1000-fold higher than
Activity of conventional antifungal agents, fludioxonil, strobilurin and antimycinA, which target the oxidative and osmotic stress response systems, was elevated by co-application of certain analogs of benzaldehyde. Fungal tolerance to 2,3-dihydroxybenzaldehyde or 2,3-dihydroxybenzoic acid was foun...
1,4-Bis-(2,3-epoxypropylamino)-9,10-anthracenedione (1) and related derivatives were assayed for antifungal, antimicrobial, and plant growth regulatory activity. Compound 1 was extremely potent against several strains of fungi, bacteria, and algae (MIC <2 ppm) and controlled two types of downy mildew by 90–100% at a dose of 12 ppm.
Zev Lidert; David H. Young; Margaret M. Bowers-Daines; Samuel E. Sherba; Raj J. Mehta; Barry C. Lange; Colin Swithenbank; Hiroshi Kiyokawa; Mary G. Johnson; Susan L. Morris-Natschke; Kuo-Hsiung Lee
An asymmetric, potentially bidentate dioxime ligand (H2 L) was formed by condensation of 4-biphenylchloroglyoxime and napthyl-1-amine. Two equivalents of H2 L were reacted with CoCl2 ?·?6H2 O under appropriate conditions with deprotonation of the dioxime ligand. A series of new organocobaloxime derivatives of the type [CoR(HL)2 Py], [CoRL2 PyB2 F4 ], and [CoRL2 Py(Cu(phen))2 ] (H2 L?=?4-(napthyl-1-amino)biphenylglyoxime; phen?=?1,10-phenathroline; R?=?izopropyl and benzyl; Py?=?pyridine) were synthesized. The products were characterized by elemental analysis, molar conductance, FT-IR, (1) H NMR, and magnetic susceptibility measurements. Catecholase-like activity properties of all complexes were also studied. All complexes are catalysts for the oxidation of 3,5-di-tert-butylcatechol to 3,5-di-tert-butyl-1,2-benzoquinone in methanol. Antimicrobial activity studies of H2 L and the six complexes were carried out on standard strains (human pathogenic) of bacteria (Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Bacillus cereus, Enterococcus faecalis, Streptococcus pneumoniae, Listeria monocytogenes, Bacillus subtilis, Escherichia coli, Pseudominas aeruginosa, Salmonella typhi) and the yeast Candida albicans. The compounds showed a significant inhibition of the growth of the Gram-positive bacteria tested. Among the tested microorganisms, S. aureus was the most sensitive strain, especially to H2 L and its complexes. PMID:24003018
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.
This study analyzed potential drug interactions (PDIs) of antimicrobials used in patients of hematopoietic stem cell transplantation and identified associated factors. The sample consisted of 70 patients admitted to a hospital in Săo Paulo. The PDIs were analyzed through the consultation of the Drug Interactions Facts and Drug Interactions Handbook. Descriptive statistics and logistic regression were used. Half of the sample was exposed to 13 PDIs, which occurred with fluconazole (53.8%), ciprofloxacin (30.8%) and sulfamethoxazole-trimethoprim (15.4%). Most (92.3%) were of moderate severity, with good evidence (61.6%), early delayed effect (61.5%) and need to have their therapy monitored (76.9%). Patients with four or more medications (p<0.001), aged between 40-49 years of age (p <0.001), and being male (p<0.001) were associated with PDIs. A PDI may result in adverse outcomes, impacting patients' morbidity and mortality. Combination regimens can be safe, provided there is careful monitoring by professionals involved in care delivery. PMID:21876949
Guastaldi, Rosimeire Barbosa Fonseca; Secoli, Silvia Regina
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
The presence of bacterial colonization in non-healing wounds and burn injuries interferes significantly with the normal process of healing. Recent evidence suggests that nitric oxide (NO) plays an important role in host defense against infection and regulates wound healing and angiogenesis. We investigated the potential application of a medical-grade gaseous form of NO (gNO) as a novel antibacterial agent in
A. Ghaffari; C. C. Miller; B. McMullin; A. Ghahary
The in vitro activities of two new cephem antibiotics, ICI 193428 and ICI 194008, were compared with those of cefpirome, cefotaxime, ceftazidime, and piperacillin. Essentially all strains of the family Enterobacteriaceae were inhibited by both study drugs at concentrations of less than or equal to 4 micrograms/ml. Both new cephems were comparable to ceftazidime against Pseudomonas aeruginosa (MIC for 90% of strains, 8 micrograms/ml) and were the most active agents tested against Pseudomonas maltophilia (MIC for 90% of strains, 16 micrograms/ml).
Allan, J D; Eliopoulos, G M; Reiszner, E; Moellering, R C
A novel series of 5-arylidene-2,4-thiazolidinediones (TZDs) 2a-p was synthesized from the condensation of 3-((2-phenylthiazol-4-yl)methyl)thiazolidine-2,4-dione with different benzaldehyde derivatives. All the structures were confirmed by their spectral (IR, ąH NMR, ąłC NMR and mass) and elemental analytical data. The new molecules were evaluated in vivo as anti-inflammatory agents in an acute experimental inflammation, evaluating the acute phase bone marrow response and phagocyte activity. All compounds, excepting one, reduced the absolute leukocytes count due to the lower neutrophil percentage. Phagocytary index was decreased by the same molecules, while only half of them reduced the phagocytary activity. The effect was superior to meloxicam, the reference anti-inflammatory drug, for the majority of the TZD derivatives. The new molecules were also investigated for their antimicrobial properties on Gram-positive and Gram-negative bacteria and one fungal strain. Two compounds (2e and 2n) manifested growth inhibition capacity on all the tested strains. PMID:23666636
BOL-303224-A is a novel fluoroquinolone that has never been used systemically and that possesses structural modifications intended to improve its potency compared to other fluoroquinolones. This investigation was conducted to evaluate the nonclinical pharmacokinetics, safety, and pharmacodynamics of BOL-303224-A. BOL-303224-A displayed activity in in vitro antimicrobial efficacy studies and also demonstrated efficacy in an in vivo murine infection model. BOL-303224-A demonstrated excellent ocular pharmacokinetics in rabbits, with ocular mean residence times >7 h, and conjunctival concentrations in excess of the MIC(90) for nonresistant ophthalmic isolates for >12 h following a single dose. Pharmacokinetic modeling from these data indicated that BOL-303224-A has the potential to demonstrate efficacy against ophthalmologic pathogens with a TID dosing regimen. BOL-303224-A also demonstrated reasonably low plasma protein binding in rat and human models, as well as good metabolic stability across species. In studies designed to explore the nonclinical safety profile of BOL-303224-A, the compound showed excellent topical ocular tolerance in rabbits and dogs, as well as a favorable genotoxicity and phototoxicity profile. In summary, BOL-303224-A exhibits an encouraging nonclinical pharmacodynamic, pharmacokinetic, and safety profile that supports clinical development as a topical agent for the potential treatment of ophthalmic infections. PMID:17593008
Ward, Keith W; Lepage, Jean-François; Driot, Jean-Yves
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.
Clavijo, Andrea P.; Bai, Jing; Gomez-Duarte, Oscar G.
A total of 579 clinical isolates of the Bacteroides fragilis group collected from three Canadian hospitals were tested for susceptibility to five antimicrobialagents by using an agar dilution method. During the 4-year survey, isolates from intra-abdominal infections were collected from the following sites: abdominal abscesses (48%), peritoneal fluid (39%), blood (10%), and bile (3%). B. fragilis was the most prevalent species (35.4%), followed by B. thetaiotaomicron (19.2%), B. ovatus (15.9%), and B. vulgatus (11%). No metronidazole- or imipenem-resistant strains were found during the survey. Resistance profiles varied among the different species tested: 7.8, 2.9, and 7.3% of B. fragilis strains (n = 205) and 68.1, 17.2, and 9.4% of non-B. fragilis strains (n = 373) were resistant to cefotetan, cefoxitin, and clindamycin, respectively. B. fragilis and B. vulgatus demonstrated lower resistance rates than B. thetaiotaomicron, B. ovatus, B. distasonis, and B. caccae. During the study, rates of resistance to cefotetan and clindamycin fluctuated but rates of resistance to cefoxitin increased, particularly at one center. These data indicate a need to determine the susceptibility patterns of the B. fragilis group periodically at each hospital.
Turgeon, P; Turgeon, V; Gourdeau, M; Dubois, J; Lamothe, F
The effects of modified atmosphere packaging (MAP) [bioriented polypropylene (BOPP-1 or BOPP-2)] in combination with antimicrobialagents Bacillus subtilis, 107colony-forming units (cfu)ml?1; ethylenediamine tetraacetic acid, calcium disodium salt hydrate (EDTA) (0.1%); or 4-hexylresorcinol (4-HR) (0.15%) on postharvest decay control and quality retention of litchi cv. McLean's Red were assessed as possible replacements for commercial SO2 fumigation. Fruits dipped in B.
There is no consensus regarding the benefit versus harm of antibiotic therapy for treatment of disease due to enterohemorrhagic\\u000a Escherichia coli O157. The effects in vitro of subinhibitory concentrations of 13 antimicrobialagents on the release of Shiga toxin (Stx)\\u000a by three different Escherichia coli O157 strains expressing Stx 1 or Stx 2 either alone or in combination were investigated.
Infusion phlebitis is a common clinical problem that is observed with some antimicrobialagents, when being administered intravenously.\\u000a In this study, cultured murine fibroblasts and immortalised human endothelial cells were exposed to three antibiotics at clinically\\u000a relevant concentrations to assess their toxic potential in two established cytotoxicity assays. BALB\\/c 3T3 fibroblasts and\\u000a Eahy926 endothelial cells were exposed to quinupristin\\/dalfopristin (QD),
Three series of rhodanine derivatives bearing a quinoline moiety (6a-h, 7a-g, and 8a-e) have been synthesized, characterized, and evaluated as antibacterial agents. The majority of these compounds showed potent antibacterial activities against several different strains of Gram-positive bacteria, including multidrug-resistant clinical isolates. Of the compounds tested, 6g and 8c were identified as the most effective with minimum inhibitory concentration (MIC) values of 1 ?g/mL against multidrug-resistant Gram-positive organisms, including methicillin-resistant and quinolone-resistant Staphylococcus aureus (MRSA and QRSA, respectively). None of the compounds exhibited any activity against the Gram-negative bacteria Escherichia coli 1356 at 64 ?g/mL. The cytotoxic activity assay showed that compounds 6g, 7g and 8e exhibited in vitro antibacterial activity at non-cytotoxic concentrations. Thus, these studies suggest that rhodanine derivatives bearing a quinoline moiety are interesting scaffolds for the development of novel Gram-positive antibacterial agents. PMID:23787100
Antimicrobialagents 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 antimicrobialagents (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 antimicrobialagents 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 antimicrobialagents in a responsible manner that benefits both the individual patient and the community.
Leekha, Surbhi; Terrell, Christine L.; Edson, Randall S.
We have investigated the control of halophilic histamine-producing bacteria, Photobacterium phosphoerum and Photobacterium damselae by using vapor of essential oils and other agents. Three of fourteen essential oils showed high antibacterial activity against histamine-producing bacteria. Among food additives and detergents, ten of twenty-one food additives and seven of nine detergents also showed antibacterial activity. Low concentrations of sodium chloride suppressed the growth of both species. We examined the resistance of these bacteria to dryness on food contact surfaces. After 0.5 hours, no viable cells were detected. So, the bacteria were sensitive to dry conditions. These results should contribute to development of the techniques to prevent histamine food poisoning. PMID:22200797
Three series of new trifluoromethyl substituted quinolone derivatives were synthesized (4a-f, 6a-f and 8a-f) from corresponding substituted anilines by multi-step reactions. The regioselective alkylation with different alkyl halides were carried out by approaching two different routes to get the final products in good yield. Newly synthesized compounds were characterized by spectral study and also by C, H, N analyses. Three dimensional structure of 2b and 4b were also confirmed by single crystal X-ray studies. The final compounds (4a-f, 6a-f and 8a-f) were screened for their in-vitro antibacterial and antifungal activity by well plate method (zone of inhibition). The results revealed that, compounds 4a, 6b, 6c and 8e showed significant antibacterial activity as compared to the standard drug Ciprofloxacin. The compound 8a was found to be a potent antifungal agent. PMID:23994870
Garudachari, B; Isloor, Arun M; Satyanarayana, M N; Fun, Hoong-Kun; Pavithra, N; Kulal, Ananda
Due to concerns about the current therapeutic modalities for Helicobacter pylori infection, e.g., the increased emergence of drug-resistant strains and the adverse reactions of drugs currently administered, there is a need to develop an anti-H. pylori agent with higher efficacy and less toxicity. The antibacterial activity of TG44, an anti-H. pylori agent with a novel structural formula, against 54 clinical isolates of H. pylori was examined and compared with those of amoxicillin (AMX), clarithromycin (CLR), and metronidazole (MNZ). Consequently, TG44 inhibited the growth of H. pylori in an MIC range of 0.0625 to 1 ?g/ml. The MIC ranges of AMX, CLR, and MNZ were 0.0078 to 8 ?g/ml, 0.0156 to 64 ?g/ml, and 2 to 128 ?g/ml, respectively. The antibacterial activity of TG44 against AMX-, CLR-, and MNZ-resistant strains was nearly comparable to that against drug-susceptible ones. In a pH range of 3 to 7, TG44 at 3.13 to 12.5 ?g/ml exhibited potent bactericidal activity against H. pylori in the stationary phase of growth as early as 1 h after treatment began, in contrast to AMX, which showed no bactericidal activity at concentrations of up to 50 ?g/ml at the same time point of treatment. TG44 at 25 ?g/ml exhibited no antibacterial activity against 13 strains of aerobic bacteria, suggesting that its antibacterial activity against H. pylori is potent and highly specific. The present study indicated that TG44 possesses antibacterial activity which manifests quickly and is potentially useful for eradicating not only the antibiotic-susceptible but also the antibiotic-resistant strains of H. pylori by monotherapy.
A total of 280 weaned pigs (Landrace x Yorkshire x Duroc) were used in a 28-d growth study to investigate the effect of feeding different levels of potato proteins on growth performance, nutrient digestibility, immune response, small intestinal morphology, and bacterial populations in feces and large intestine. Pigs (initially 6.42 +/- 0.74 kg of BW and 23 +/- 3 d of age) were randomly allotted to 5 treatments on the basis of BW, each treatment composed of 4 pens, each pen having 14 pigs. Dietary treatments included positive control (PC; basal diet + 150 mg/kg apramycin and 10 mg/ kg colistin sulfate); and potato protein (PP), consisting of the basal diet with 0, 0.25, 0.50, or 0.75% of potato protein. Diets were fed in 2 phases: phase I (d 0 to 14 postweaning) and phase 2 (d 14 to 28 postweaning). Potato protein was extracted from a value-added type of the new potato variety, Solanum tuberosum L. cv. Gogu valley, and was shown to have a minimum inhibitory concentration of 300 to 500 mug/mL. Performance of PC was compared with 0.25 to 0.75% PP, whereas linear and quadratic trends of increasing PP (0 to 0.75% PP) were tested. Over the 28-d trial, pigs fed the PC diets showed improved overall ADG (P < 0.05) and G:F (P = 0.090) compared with pigs fed PP, whereas increasing levels of PP linearly improved ADG (P < 0.05), ADFI (P = 0.052), and G:F (P = 0.098). The digestibility of DM and CP in both the phases was greater in PC than PP, and feeding of PP linearly improved the DM digestibility (P < 0.05) in phase II. The bacterial populations in the feces of pigs fed PC and PP were comparable, except for total bacteria and coliform bacteria in the feces at d 14 and 28, which were decreased in PC; and feeding of PP was effective in linearly reducing the populations of microbes in feces and contents of cecum, colon, and rectum. There was linear increase (P < 0.10) in skin-fold thickness in response to phytohemagglutinin with an increase in PP levels. Haemagglutinin titers on d 21 were greater (P = 0.054) in PC, and at d 28 the haemagglutinin titers were quadratically affected in pigs fed PP (P = 0.070). There was a trend toward a decrease in crypt depth (P = 0.068) and a greater villus height:crypt depth ratio (P = 0.082) of ileum in PC compared with PP. These results suggest that PP may be an alternative to medicated feed with antibiotics because it showed antimicrobial activity by effectively reducing the population of coliform bacteria and also improved the performance of weanling pigs. PMID:18344303
Jin, Z; Yang, Y X; Choi, J Y; Shinde, P L; Yoon, S Y; Hahn, T-W; Lim, H T; Park, Y; Hahm, K-S; Joo, J W; Chae, B J
The methanolic extract of the leaves of Peltophorum vogelianum (Caesalpiniaceae) afforded a new phytoconstituent, 2-methoxy-4,5-dihydroxy-1(7,8-dihydroxyethylene)-8-?-D-glucuropyranoside named as peltophorumyl-?-D-glucuropyranoside (5), along with four known phytoconstituents, 1-pentatriacontanol (1), friedelin (2), ?-sitosterol (3) and ?-sitosterol-?-D-glucopyranoside (4), which have not been isolated previously from this plant. Their structures were established on the basis of chemical and physical evidence (IR, H-NMR, C-NMR, DEPT, HSQC, HMBC
Mehtab Parveen; Raza Murad Ghalib; Zakia Khanam; Sayed Hasan Mehdi; Mohammed Ali
The effects of feed supplementation with the approved antimicrobialagents 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 antimicrobialagents used in broiler chicken production.
A persistent need exists for effective treatment agents for mycobacterial infections. This research investigated the effectiveness of the Hypericum perforatum herb (commonly known as St John's wort; SJW) in its growth inhibition of mycobacteria. A SJW extract was effective at inhibiting five nonpathogenic Mycobacterium isolates and Bacillus subtilis, but not Escherichia coli. Quantitative studies of concentration sensitivity to the SJW extract were performed with minimal bactericidal concentrations (MBC) ranging from 0.33 to 2.66?mg extract/mL. The SJW compounds hyperforin (Hfn), hypericin (Hpn), and pseudohypericin (Phn) were quantified in the extract using HPLC. The SJW extract solution of 133?mg extract/mL used in this study contained 2.3?mg Hfn/mL, 0.8?mg Hpn/mL, and 2.1?mg Phn/mL. Purified Hfn, Hpn, and Phn were tested for inhibitory activity against Mycobacterium JLS (M. JLS) at similar concentrations used in the crude extract. While Hfn was inhibitory at 46?µg/mL, none of the purified SJW constituents were bactericidal at concentrations corresponding to SJW treatments. Scanning electron microscopy (SEM) analysis of SJW-treated M. JLS cells showed changes in cell surface morphology. PMID:22294548
Mortensen, Trent; Shen, Shujie; Shen, Fenann; Walsh, Marie K; Sims, Ronald C; Miller, Charles D
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
Infectious bovine keratoconjunctivitis (IBK) has been associated with ocular infections by Moraxella bovis, the established etiologic agent of IBK, and more recently, Moraxella bovoculi, a recently described species of Moraxella. To assist in designing rational treatment regimens for M. bovoculi infections associated with IBK, the in vitro susceptibilities of 57 M. bovoculi field isolates cultured from eyes of cattle with IBK in California from 2002 through 2007 were determined. The minimum inhibitory concentration required to inhibit the growth of 90% of organisms (MIC(90)) of the following 18 antibiotics tested in the present study were: danofloxacin and enrofloxacin: ?0.12 µg/ml; ampicillin and ceftiofur: ?0.25 µg/ml; penicillin: 0.25 µg/ml; gentamicin: ?1 µg/ml; chlortetracycline, oxytetracycline, and tiamulin: 1 µg/ml; florfenicol: 0.5 µg/ml; trimethoprim-sulfamethoxazole: ?2/38 µg/ml; clindamycin: 2 µg/ml; neomycin and tilmicosin: ?4 µg/ml; tulathromycin: 4 µg/ml; spectinomycin and tylosin: 16 µg/ml; and sulfadimethoxine: >256 µg/ml. The low MIC(90) of these M. bovoculi isolates suggests that commonly used antibiotics for treatment of IBK associated with M. bovis should also be effective against M. bovoculi. PMID:21908289
New furanone derivatives incorporating the indolin-2-one moiety 3 were prepared via the Perkin reaction of isatins 1 with aroylpropionic acids 2 under conventional conditions or microwave irradiation. A series of functionally heterocyclic derivatives (e.g., pyridazines, pyrroles, and sulfonamides) incorporating the indolin-2-one moiety was achieved via reaction of 3 with different reagents under microwave irradiation conditions. The newly synthesized compounds were characterized on the basis of FTIR, (1)H, (13)C NMR and mass spectral studies. Some of the new synthesized compounds were screened for antibacterial activity against Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus), Gram-negative bacteria (Escherichia coli and Shigilla flexneri) and antifungal activity against Aspergillus flavus and Candida albicans. Compound 8 j was equipotent to chloramphenicol in inhibiting the growth of E. coli minimum inhibitory concentration (MIC 2.5 ?g/mL). Compound 8j may possibly be used as a lead compound for developing a new antibacterial agents. The antibacterial activity is expressed as the corresponding MIC (?g/mL) values. PMID:22651801
The MICs of ceftiofur and other antimicrobialagents, tested for comparison, for 515 bacterial isolates of pigs from the United States, Canada, and Denmark with various diseases were compared. The organisms tested included Actinobacillus pleuropneumoniae, Escherichia coli, Pasteurella multocida, Salmonella choleraesuis, Salmonella typhimurium, Streptococcus suis, Streptococcus dysgalactiae subsp. equisimilis, Streptococcus equi subsp. equi, and Streptococcus equi subsp. zooepidemicus. In addition to ceftiofur, the following antimicrobialagents or combinations were tested: enrofloxacin, ampicillin, sulfamethazine, trimethoprim-sulfadiazine (1:19), erythromycin, lincomycin, spectinomycin, lincomycin-spectinomycin (1:8), tilmicosin, and tetracycline. Tilmicosin was only tested against the U.S. isolates. Overall, ceftiofur and enrofloxacin were the most active antimicrobialagents tested against all isolates, with MICs inhibiting 90% of isolates tested (MIC90s) of < or = 2.0 and < or = 1.0 microgram/ml, respectively. Erythromycin, sulfamethazine, spectinomycin, and lincomycin demonstrated limited activity against all of the organisms tested, with MIC90s of > or = 8.0, > or = 256.0, > or = 32.0, and > or = 16.0 micrograms/ml, respectively. Trimethoprim-sulfadiazine was active against isolates of A. pleuropneumoniae, S. choleraesuis, S. typhimurium, P. multocida, S. equi, and S. suis (MIC90s, < or = 0.5 microgram/ml) but was less active against the E. coli strains tested (MIC90, > 16.0 micrograms/ml). Ampicillin was active against the P. multocida, S. suis, and S. equi isolates tested (MIC90s, 0.5, 0.06, and 0.06 micrograms/ml, respectively) and was moderately active against S. typhimurium (MIC90s, 2.0 micrograms/ml). However, this antimicrobialagent was much less active when it was tested against A. pleuropneumoniae, S. cholerae-suis, and E. coli (MIC90s, 16.0, > 32.0, and 32.0 micrograms/ml, respectively). Against the U.S. isolates of A. pleuropneumoniae and P. multocida, tilmicosin was moderately active (MIC90s, 4.0 and 8.0 micrograms/ml, respectively). However, this compound was not active against the remaining U.S. isolates (MIC90s, > 64.0 micrograms/ml). Differences in the MICs from one country to another were not detected with enrofloxacin, ceftiofur, or lincomycin for the strains tested, but variations in the MICs of the remaining antimicrobialagents were observed.
Salmon, S A; Watts, J L; Case, C A; Hoffman, L J; Wegener, H C; Yancey, R J
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 antimicrobialagent 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 antimicrobialagent, 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 antimicrobialagents could be explained by differences in pharmacokinetics or pharmacodynamic activity.
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
This is the first report on aurones as a new class of drugs with anti-inflammatory and antimicrobialagents. A series of 2,2-bisaminomethylated aurone analogues (4a-j) were synthesized by Mannich reaction from 1,3,5-trimethoxybenzene in three steps. The structures of the newly synthesized compounds were confirmed by IR, (1)H NMR and mass spectral analysis. All the synthesized compounds were screened against the pro-inflammatory cytokines (TNF-alpha, IL-6) and antimicrobial (antibacterial and antifungal) activity. Compounds 4a, 4b, 4c, 4d, and 4e showed promising results against IL-6 at 10 microM concentration (74-100%). Compounds 4a, 4b and 4c were found to be active against TNF-alpha (76-100%) at 10 microM. Interestingly, all compounds have shown good antimicrobial activity. Compounds 4d, 4e and 4f showed excellent antimicrobial activity as compared with standard drugs. PMID:20430485
Bandgar, Babasaheb P; Patil, Sachin A; Korbad, Balaji L; Biradar, Satish C; Nile, Shivraj N; Khobragade, Chandrahasya N
The fight against antibiotic resistance is one of the most significant challenges to public health of our time. The inevitable development of resistance following the introduction of novel antibiotics has led to an urgent need for the development of new antibacterial drugs with new mechanisms of action that are not susceptible to existing resistance mechanisms. One such compound is HAMLET, a natural complex from human milk that kills Streptococcus pneumoniae (the pneumococcus) using a mechanism different from common antibiotics and is immune to resistance-development. In this study we show that sublethal concentrations of HAMLET potentiate the effect of common antibiotics (penicillins, macrolides, and aminoglycosides) against pneumococci. Using MIC assays and short-time killing assays we dramatically reduced the concentrations of antibiotics needed to kill pneumococci, especially for antibiotic-resistant strains that in the presence of HAMLET fell into the clinically sensitive range. Using a biofilm model in vitro and nasopharyngeal colonization in vivo, a combination of HAMLET and antibiotics completely eradicated both biofilms and colonization in mice of both antibiotic-sensitive and resistant strains, something each agent alone was unable to do. HAMLET-potentiation of antibiotics was partially due to increased accessibility of antibiotics to the bacteria, but relied more on calcium import and kinase activation, the same activation pathway HAMLET uses when killing pneumococci by itself. Finally, the sensitizing effect was not confined to species sensitive to HAMLET. The HAMLET-resistant respiratory species Acinetobacter baumanii and Moraxella catarrhalis were all sensitized to various classes of antibiotics in the presence of HAMLET, activating the same mechanism as in pneumococci. Combined these results suggest the presence of a conserved HAMLET-activated pathway that circumvents antibiotic resistance in bacteria. The ability to activate this pathway may extend the lifetime of the current treatment arsenal.
Marks, Laura R.; Clementi, Emily A.; Hakansson, Anders P.
Objectives To assess the effects of N-acetylcysteine (NAC) on organism viability in planktonic and biofilm phases, biofilm thickness, and extracellular polysaccharide content. Methods We performed time-kill curves and broth macrodilution assays of bacterial and fungal clinical isolates with varying concentrations of NAC. We also created in-vitro bacterial biofilms, incubated them with NAC or control, and then stained with propidium iodide and FITC-labelled concanavalin A. We measured biofilm thickness, number of non-viable cells, and fluorescent intensity as a marker of extracellular matrix via a confocal laser scanning microscope. All experiments were conducted in triplicate. Tested organisms included methicillin-sensitive and - resistant Staphylococcus aureus (MSSA, MRSA), S. epidermidis, vancomycin-resistant Enterococcus faecalis (VRE), Pseudomonas aeruginosa, Enterobacter cloacae, Klebsiella pneumoniae, Candida albicans and C. krusei. Results NAC 80 mg/ml was uniformly bactericidal (>99.9% reduction) against all tested bacteria with no recoverable organisms after 30 minutes of incubation, but was fungistatic against candida species. Minimum inhibitory and bactericidal concentrations of NAC ranged from 5–10 mg/ml. Biofilm thickness was significantly decreased in NAC-treated biofilms for all organisms except VRE. The number of non-viable cells in NAC-treated Gram-positive biofilms was increased (p<0.05 for MRSA and VRE). NAC-treated Gram-negative biofilms had scant cellularity and lacked complex 3-dimensional structures that were characteristic of controls. Fluorescent intensity was similar in the experimental and control arms. Conclusions NAC is bactericidal against clinically relevant and drug-resistant bacteria and also leads to biofilm disruption. NAC has the potential for use as a novel agent for prevention or treatment of biofilm-related infections.
The aim of the present study was to determine whether the application of different primers containing antibacterial agents (Micro Prime, Seal&Protect, and Gluma Desensitizer) can affect the shear bond strength (SBS) of an orthodontic resin composite. Seventy-two crowns of extracted lower human incisors were mounted in acrylic resin leaving the buccal surface of the crowns parallel to the base of the moulds. The teeth were randomly distributed into three experimental and one control group, each containing 18 teeth. In each experimental group, the primers were applied to the etched enamel surfaces. In the control group, no antibacterial primer was used. An orthodontic composite resin was applied to the surface into cylindrical-shaped plastic matrices after application of an orthodontic adhesive primer (Transbond XT). For shear bond testing, a stubby-shaped force transducer apparatus (Ultradent) was applied at a crosshead speed of 1 mm/minute to each specimen at the interface between the tooth and the composite until failure occurred. A Kruskal-Wallis one-way ANOVA and a Mann-Whitney U-test with a Bonferroni adjustment were used for statistical analysis. There was no significant difference between Seal&Protect (27.98 +/- 8.73 MPa) and the control (35.15 +/- 7.85 MPa) (P > 0.05). However, Gluma (21.61 +/- 7.96 MPa) and Micro Prime (14.89 +/- 5.55 MPa) caused a decrease in bond strength (P < 0.05). No statistically significant difference was observed between Seal&Protect and Gluma (P > 0.05). As triclosan containing Seal&Protect did not cause a significant decrease in bond strength, it can potentially be used under an orthodontic resin composite to obtain an antibacterial effect. However, further in vivo studies are required. PMID:16135539
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 of newborns with proven sepsis during the years 2000-2002 in our NICU. The charts of babies with sepsis were evaluated for clinical characteristics, positive cultures and antimicrobial susceptibilities, retrospectively. Although most of the admitted patients were premature (76.5%), the frequency of proven sepsis was quite low, at 9.1% among 909 newborns. Mortality rate in sepsis was 16%. The most commonly isolated micro-organisms were coagulase-negative staphylococci (CoNS) (31.3%), fungi (19.2%), Staphylococcus aureus (13%) and Klebsiella pneumoniae (10.5%). Methicillin resistance for CoNS was 92.3% and for S. aureus was 72.7%. In the last year, a significant increase in the frequency of Klebsiella pneumoniae (8.3 vs 14.2%), CoNS (27.1 vs 37.1%), Pseudomonas aeruginosa (2.1 vs 8.6%) and fungal infections (18.8 vs 20%) was observed compared to the previous years. An initial empirical antibiotic therapy for late-onset sepsis was designed with teicoplanin + piperacillin-tazobactam/meropenem + antifungal (fluconazole or amphotericin B) as the best combination to cover this spectrum until the culture results arrive. However, this combination is only compatible with our results and may not be applied in all units. Every unit must follow the bacterial spectrum and antibacterial resistance patterns to choose their specific empirical treatment strategy for nosocomial infections. PMID:16562780
The Upjohn oxazolidinones, U-100592 and U-100766, are orally bioavailable synthetic antimicrobialagents with spectra of activity against antibiotic-susceptible and -resistant gram-positive pathogens. In several mouse models of methicillin-resistant Staphylococcus aureus infection, U-100592 and U-100766 yielded oral 50% effective doses (ED50) ranging from 1.9 to 8.0 mg/kg of body weight, which compared favorably with vancomycin subcutaneous ED50 values of 1.1 to 4.4 mg/kg. Similarly, both compounds were active versus a Staphylococcus epidermidis experimental systemic infection. U-100592 and U-100766 effectively cured an Enterococcus faecalis systemic infection, with ED50 values of 1.3 and 10.0 mg/kg, and versus a vancomycin-resistant Enterococcus faecium infection in immunocompromised mice, both drugs effected cures at 12.5 and 24.0 mg/kg. Both compounds were exceptionally active in vivo against penicillin- and cephalosporin-resistant Streptococcus pneumoniae, with ED50 values ranging from 1.2 to 11.7 mg/kg in systemic infection models. In soft tissue infection models with S. aureus and E. faecalis, both compounds exhibited acceptable curative activities in the range of 11.0 to 39.0 mg/kg. U-100766 was also very active versus the Bacteroides fragilis soft tissue infection model (ED50 = 46.3 mg/kg). In combination-therapy studies, both U-100592 and U-100766 were indifferent or additive in vivo against a monomicrobic S. aureus infection in combination with other antibiotics active against gram-positive bacteria and combined as readily as vancomycin with gentamicin in the treatment of a polymicrobic S. aureus-Escherichia coli infection. U-100592 and U-100766 are potent oxazolidinones active against antibiotic-susceptible and -resistant gram-positive pathogens in experimental systemic and soft tissue infections.
Ford, C W; Hamel, J C; Wilson, D M; Moerman, J K; Stapert, D; Yancey, R J; Hutchinson, D K; Barbachyn, M R; Brickner, S J
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
The objective of this study was to measure the effect of broiler processing on the prevalence, serotype, and antimicrobial resistance profiles of salmonellae. Twenty U.S. commercial processing plants representing eight integrators in 13 states were included in the survey. In each of four replications, 10 carcasses from one flock were collected at rehang and 10 more carcasses were collected at postchill; each carcass was sampled by whole-carcass rinse. Salmonella organisms were isolated from carcass rinses by standard cultural techniques, serotypes were determined, and the resistance to 15 antimicrobials was measured. Overall, Salmonella was detected on 72% of carcasses at rehang (ranging from 35 to 97%) and on 20% of carcasses postchill (ranging from 2.5 to 60%). In every instance, a significant (P < 0.05) decrease in Salmonella prevalence was noted between rehang and postchill. The four most common serotypes, accounting for 64% of all Salmonella isolates, were Kentucky, Heidelberg, Typhimurium, and Typhimurium var. 5-; most isolates of Kentucky (52%), Heidelberg (79%), and Typhimurium (54%) serotypes were susceptible to all antimicrobial drugs tested. However, only 15% of the Typhimurium var. 5- isolates were pansusceptible; more than one-half of the isolates of this serotype were resistant to three or more drugs. No isolate of any serotype exhibited resistance to amikacin, ceftriaxone, ciprofloxacin, or trimethoprim-sulfamethoxazole. These data demonstrate that although processing lessens carcass contamination with Salmonella, antimicrobial-resistant isolates may still be present. PMID:19722391
Berrang, M E; Bailey, J S; Altekruse, S F; Shaw, W K; Patel, B L; Meinersmann, R J; Fedorka-Cray, P J
The synthesis, in vitro antimicrobial and cytotoxic activities of some novel hexahydroquinolines supported with various pharmacophores are described. The results revealed that 18 compounds displayed pronounced activity against Staphylococcus aureus and Escherichia coli bacteria beside a moderate antifungal activity. Compound 25 is the most active candidate with equipotency to ampicillin against S. aureus, E. coli and Pseudomonas aeruginosa, together with an obvious antifungal activity. Additionally, 12 compounds showed remarkable cytotoxic efficiency against human colon carcinoma HT29, hepatocellular carcinoma Hep-G2 and Caucasian breast adenocarcinoma MCF7 cell lines. Among these, the analogs 22 and 25 proved to be the most active cytotoxic members. Collectively, the results would suggest that compounds 22 and 25 could be considered as possible dual antimicrobial-anticancer agents. PMID:22136527
Faidallah, Hassan M; Rostom, Sherif A F; Asiri, Abdullah M; Khan, Khalid A; Radwan, Mohammed F; Asfour, Hani Z
The antimicrobial and antifungal effects of different concentrations of chloroform/methanol fractions of Scoparia dulcis were investigated. The isolated fractions were tested against different bacteria like Salmonella typhii, Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, and Proteus vulgaris and fungal strains such as Alternaria macrospora, Candida albicans, Aspergillus niger, and Fusarium oxysporum. The isolated fractions exhibited significant antimicrobial and antifungal activity against all the tested organisms compared with respective reference drugs. The isolated fractions of S. dulcis showed properties like antimicrobial and antifungal activities that will enable researchers in turn to look for application-oriented principles. PMID:17004904
Latha, M; Ramkumar, K M; Pari, L; Damodaran, P N; Rajeshkannan, V; Suresh, T
Stir-bar-sorptive extraction (SBSE) with liquid desorption (LD) and ultra-high-performance liquid chromatography–electrospray\\u000a ionization triple-quadrupole tandem mass spectrometry (UHPLC–(ESI)MS–MS) were used for analysis of six personal care products\\u000a in environmental water: four UV filters (2,2-dihydroxy-4-methoxybenzophenone, benzophenone-3, octocrylene, and octyldimethyl-p-aminobenzoic acid) and two antimicrobialagents (triclocarban and triclosan). Experimental conditions that affect SBSE-LD\\u000a sorption efficiency (extraction time and temperature, sample pH, and ionic
Marta Pedrouzo; Francesc Borrull; Rosa Maria Marcé; Eva Pocurull
A bioassay was developed to measure the minimum concentration of an antimicrobial drug that disrupts the colonization resistance mediated by model human intestinal microbiota against Salmonella invasion of Caco-2 intestinal cells. The bioassay was used to measure the minimum disruptive concentrations (MDCs) of drugs used in animal agriculture. The MDCs varied from 0.125 ?g/ml for some broad-spectrum antimicrobial drugs (e.g., streptomycin) to 16 ?g/ml for drugs with limited spectra of antimicrobial activity (e.g., lincomycin). The acceptable daily intake (ADI) residue concentration calculated on the basis of the MDCs were higher for erythromycin, lincomycin, and tylosin than the ADI residue concentrations calculated on the basis of the MICs. The MDC-based ADI values for apramycin, bacitracin, neomycin, novobiocin, penicillin G, streptomycin, tetracycline, and vancomycin were lower than the reported MIC-based ADI values. The effects of antimicrobial drugs at their MDCs on the bacterial composition of the microbiota were observed by denaturing gradient gel electrophoresis of 16S rRNA sequences amplified by PCR. Changes in the population composition of the model colonization resistance microbiota occurred simultaneously with reduced colonization resistance. The results of this study suggest that direct assessment of the effects of antimicrobial drugs on colonization resistance in an in vitro model can be useful in determining ADI values.
Wagner, R. Doug; Johnson, Shemedia J.; Cerniglia, Carl E.
Background Traditional folk medicinal plants have recently become popular and are widely used for primary health care. Since Thailand has a great diversity of indigenous (medicinal) plant species, this research investigated 52 traditionally used species of Thai medicinal plants for their in vitro cytotoxic, antioxidant, lipase inhibitory and antimicrobial activities. Methods The 55 dried samples, derived from the medicinally used parts of the 52 plant species were sequentially extracted by hexane, dichloromethane, ethanol and water. These 220 extracts were then screened for in vitro (i) cytotoxicity against four cell lines, derived from human lung (A549), breast (MDA-MB-231), cervical (KB3-1) and colon (SW480) cancers, using the MTT cytotoxicity assay; (ii) antioxidant activity, analyzed by measuring the scavenging activity of DPPH radicals; (iii) lipase inhibitory activity, determined from the hydrolytic reaction of p-nitrophenyllaurate with pancreatic lipase; and (iv) antimicrobial activity against three Gram-positive and two Gram-negative bacteria species plus one strain of yeast using the disc-diffusion method and determination of the minimum inhibitory concentration by the broth micro-dilution assay. Results The crude dichloromethane and/or ethanol extracts from four plant species showed an effective in vitro cytotoxic activity against the human cancer cell lines that was broadly similar to that of the specific chemotherapy drugs (etoposide, doxorubicin, vinblastine and oxaliplatin). In particular, this is the first report of the strong in vitro cytotoxic activity of Bauhinia strychnifolia vines. The tested tissue parts of only six plant species (Allium sativum, Cocoloba uvifera, Dolichandrone spathacea, Lumnitzera littorea, Sonneratia alba and Sonneratia caseolaris) showed promising potential antioxidant activity, whereas lipase inhibitory activity was only found in the ethanol extract from Coscinum fenestratum and this was weak at 17-fold lower than Orlistat, a known lipase inhibitor. The highest antimicrobial activity was observed in the extracts from S. alba and S. caseolaris against Pseudomonas aeruginosa and Candida albicans, respectively. Conclusion The Thai medicinal plant B. strychnifolia is first reported to exert strong in vitro cytotoxic activities against human cancer cell lines and warrants further enrichment and characterization. The broad spectrum of the biological activities from the studied plant extracts can be applied as the guideline for the selection of Thai medicinal plant species for further pharmacological and phytochemical investigations.
Miconazole at concentrations between 5 and 20 mgl-1 inhibited hyphal growth and sporulation in a wide range of fungi commonly associated with plants. These fungi included 4 Oomycetes, 11 Deuteromycetes, 4 Ascomycetes and 4 common airborne contaminants of plant tissue culture. The phytotoxicity of 20 mgl-1 miconazole was also tested against a wide range of in vitro plant cultures. Shoot
J. L. Tynan; A. J. Conner; R. C. Macknight; R. T. M. Poulter
Abstract Treatment of Escherichia coli O157:H7 by certain antimicrobialagents often exacerbates the patient's condition by increasing either the release of preformed Shiga toxins (Stx) upon cell lysis or their production through the SOS response-triggered induction of Stx-producing prophages. Recommended subinhibitory concentrations (sub-MICs) of azithromycin (AZI), gentamicin (GEN), imipenem (IMI), and rifampicin (RIF) were evaluated in comparison to norfloxacin (NOR), an SOS-inducer, to assess the role of the SOS response in Stx release. Relative expression of recA (SOS-inducer), Q (late antitermination gene of Stx-producing prophage), stx1, and stx2 genes was assessed at two sub-MICs of the antimicrobials for two different strains of E. coli O157:H7 using reverse transcription-real-time polymerase chain reaction. Both strains at the two sub-MICs were also subjected to Western blotting for LexA protein expression and to reverse passive latex agglutination for Stx detection. For both strains at both sub-MICs, NOR and AZI caused SOS-induced Stx production (high recA, Q, and stx2 gene expression and high Stx2 production), so they should be avoided in E. coli O157:H7 treatment; however, sub-MICs of RIF and IMI induced Stx2 production in an SOS-independent manner except for one strain at the first twofold dilution below MIC of RIF where Stx2 production decreased. Moreover, GEN caused somewhat increased Stx2 production due to its mode of action rather than any effect on gene expression. The choice of antimicrobial therapy should rely on the antimicrobial mode of action, its concentration, and on the nature of the strain. PMID:23808851
Nassar, Farah J; Rahal, Elias A; Sabra, Ahmad; Matar, Ghassan M
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 antimicrobialagents and also provide the possibility of tailored release kinetics by variation of anodization parameters.
Background: Respiratory infection with Pseudomonas aeruginosa is very common in patients with cystic fibrosis (CF) but antimicrobial resistance rates of CF isolates across the UK are largely unknown.Methods: The susceptibility of 417 CF patient isolates of P aeruginosa from 17 hospitals to six commonly prescribed antibiotics were examined. Isolates were tested by an agar break point dilution method and E-tests
Lippia origanoides Kunth, Lippia alnifolia Schauer, and Lippia thymoides Martius and Schauer are shrubs used in the traditional Brazilian medicine as antiseptics, as well as in the treatment of infectious diseases. This study was designed to investigate the antibacterial and antifungal activities of the methanolic extracts of these species, as new potential sources of antimicrobial drugs. The antimicrobial activity of methanolic extracts was investigated against resistant yeasts and bacteria by agar disk diffusion. Then, the MIC determination of the most active species and its fractions in hexane, dichloromethane, ethyl acetate, and water was performed. By the agar diffusion assay, all species were active against at least two microorganisms, giving evidence to support their use in the popular medicine. L. origanoides leaves exhibited the widest antimicrobial action, inhibiting the growth of two Gram-positive bacteria and two yeasts; this activity was also confirmed by the MIC evaluation. The fractionation of L. origanoides crude extracts improved the activity in spectrum and intensity. The results obtained in this study indicate that L. origanoides may be a promising alternative in the treatment of bacterial and fungal infections and in the seeking of new antimicrobial drugs.
Pinto, Cristiana da Purificacao; Rodrigues, Velize Dias; Pinto, Fernanda da Purificacao; Pinto, Renata da Purificacao; Uetanabaro, Ana Paula Trovatti; Pinheiro, Carla Santos Ribeiro; Gadea, Suzana Ferreira Magalhaes; Silva, Tania Regina dos Santos; Lucchese, Angelica Maria
Lippia origanoides Kunth, Lippia alnifolia Schauer, and Lippia thymoides Martius and Schauer are shrubs used in the traditional Brazilian medicine as antiseptics, as well as in the treatment of infectious diseases. This study was designed to investigate the antibacterial and antifungal activities of the methanolic extracts of these species, as new potential sources of antimicrobial drugs. The antimicrobial activity of methanolic extracts was investigated against resistant yeasts and bacteria by agar disk diffusion. Then, the MIC determination of the most active species and its fractions in hexane, dichloromethane, ethyl acetate, and water was performed. By the agar diffusion assay, all species were active against at least two microorganisms, giving evidence to support their use in the popular medicine. L. origanoides leaves exhibited the widest antimicrobial action, inhibiting the growth of two Gram-positive bacteria and two yeasts; this activity was also confirmed by the MIC evaluation. The fractionation of L. origanoides crude extracts improved the activity in spectrum and intensity. The results obtained in this study indicate that L. origanoides may be a promising alternative in the treatment of bacterial and fungal infections and in the seeking of new antimicrobial drugs. PMID:24109492
Pinto, Cristiana da Purificaçăo; Rodrigues, Velize Dias; Pinto, Fernanda da Purificaçăo; Pinto, Renata da Purificaçăo; Uetanabaro, Ana Paula Trovatti; Pinheiro, Carla Santos Ribeiro; Gadea, Suzana Ferreira Magalhăes; Silva, Tânia Regina Dos Santos; Lucchese, Angélica Maria
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
Plants have cholinesterases (pChEs), anti-ChEs, and activators of ChEs. We have isolated pChE from mung bean sprout. We investigated 300 plants and found that 75% of them contained anti- ChE that inhibited ChEs. Thirty-five percent contained activators of...
S. S. Thakur G. E. Garcia H. N. Leader D. Moorad- Doctor R. Gupta
Ethanol extracts from the different parts of B. orellana showed differential antimicrobial activity. It was found that the extracts of in vitro leaves showed maximum activity against Bacillus pumilus followed by the extracts from the roots and hypocotyls. The callus derived from different explants too showed antimicrobial activity. The leaf callus showed maximum activity. The zone of inhibition for the diluted extracts of in vitro hypocotyls and roots and their corresponding calli showed minimum zone of inhibition at concentration 24 mg/ml, whereas the diluted extract of in vitro leaves and leaf derived callus showed minimum zone of inhibition at 16 mg/ml. PMID:12974400
Because invasion is, either directly or via metastasis formation, the main cause of death in cancer patients, development of ef- ficient anti-invasive agents is an important research challenge. We have established a screening program for potentially anti-invasive compounds. The assay is based on organotypic confronting cultures between human invasive cancer cells and a fragment of normal tissue in three dimensions.
V. S. Parmar; M. E. Bracke; B. W. A. Vanhoecke; L. Derycke; S. Bolca; S. Possemiers; A. Heyerick; C. V. Stevens; D. D. Keukeleire; H. T. Depypere; W. Verstraete; C. A. Williams; S. T. McKenna; S. Tomar; D. Sharma; A. K. Prasad; A. L. DePass
A rabbit perforated-capsule model was utilized to study antimicrobial efficacy in treating 2-week-old Staphylococcus aureus abscesses. Animals received either ciprofloxacin (30 mg/kg), cefazolin (100 mg/kg), or ciprofloxacin (30 mg/kg) plus rifampin (20 mg/kg) every 8 h for 8 days or no antibiotic. Antibiotic levels within the abscess exceeded the MIC for the test organism. At the end of treatment, ciprofloxacin was no more effective than the control, animals receiving cefazolin had a mean log10 fall of 2.41 CFU/ml, and animals receiving ciprofloxacin plus rifampin had a mean log10 reduction of 5.06 CFU/ml (P = less than 0.01). Six days after completion of therapy, all abscesses in animals receiving ciprofloxacin plus rifampin were culture negative. Surviving organisms in animals receiving ciprofloxacin or rifampin did not develop resistance to the treatment antibiotics. In vitro time-kill curves performed with logarithmic- and stationary-phase organisms in broth, serum, and abscess fluid supernatants did not correlate with the in vivo results. Neutrophil killing studies of S. aureus pretreated with antibiotics revealed greater killing of organisms pretreated with ciprofloxacin plus rifampin than of those pretreated with cefazolin or ciprofloxacin alone. In conclusion, ciprofloxacin plus rifampin was effective therapy in this staphylococcal abscess model, compared with the moderate efficacy of cefazolin and no effect observed with ciprofloxacin alone. Enhanced neutrophil killing of S. aureus pretreated with antibiotics may be an important mechanism by which bacteria are killed in suppurative infections.
Preliminary studies of flavonoids have been realised in five native species from Taf?? del Valle (Tucumán, Argentina) used in popular medicine. Most of compounds detected were flavonoids mono and dihydroxylated in B ring. Screening for antimicrobial activity against Gram positive and Gram negative microorganisms has been realised with Lippia turbinata, Satureja parvifolia, Sambucus peruviana, Verbena officinalis and Chenopodium graveolens. The
In this study, methanolic crude extracts and their different fractions i.e. petroleum ether, carbon tetrachloride, chloroform and aqueous soluble fractions of the Allamanda cathartica (Family: Apocynaceae), Stereospermum personatum (Family: Bignoniaceae), Curcuma zedoaria (Family: Zingiberaceae), and Callistemon citrinus (Family: Myrtaceae) were subjected for antimicrobial activity. All the fractions were tested against different gram positive and gram negative bacteria and fungi to
Mohammad Rashedul Islam; Rubina Ahamed; Mohammad Ahsanul Akbar
The in vitro activity of some isolated hydroxyanthracenones belonging to the genus Karwinskia against four bacteria, six filamentous fungi and four yeast are reported. These hydroxyanthracenones were found to possess antimicrobial activity, particularly against Streptococcus pyogenes, Candida albicans, C. boidinii, C. glabrata and Cryptococcus neoformans; minimal inhibitory concentrations range between 16 and 2 microg/ml. PMID:16797144
The study investigated the formation of glucosinolate breakdown products and other biomolecules in sauerkraut using different starter cultures of lactic acid bacteria (Lactobacillus plantarum, Lactobacillus sakei, Leuconostoc mesenteroides, Pediococcus pentosaceus, Lactococcus lactis N8 and L. lactis LAC67). Moreover, we examined the antimicrobial effects of cabbage juice containing nisin and glucosinolate breakdown products. The major glucosinolates were sinigrin, glucoiberin, and glucobrassicin.
M Tolonen; S Rajaniemi; J.-M Pihlava; T Johansson; P. E. J Saris; E.-L Ryhänen
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
N. C. C. Silva; L. Barbosa; L. N. Seito; A. Fernandes Junior
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
N. C. C. Silva; L. Barbosa; L. N. Seito; A. Fernandes Junior
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
This paper presents an approach for intelligent distributed control of power plants using the concept of multi- agent systems (MAS). Solving the problem of optimally controlling a power plant based on multiple objectives, such as minimizing pollution, maximizing equipment life, etc., and coordinating each of the involved tasks that must be performed in distributed environments is a challenge, which involves
Kwang Y. Lee; Jason D. Head; Jason R. Gomes; Craig S. Williams
Due to their complex structure with several chiral centres important anticancer agents are still extracted from plants and not synthesized chemically on a commercial scale. Sustainable biopro- duction of the compounds of interest may be achieved by plant in vitro cultures. Undifferen- tiated callus and suspension cultures, which can be cultivated in large bioreactors easily, very often fail to accumulate
Michael Wink; A. Wilhelm Alfermann; Rochus Franke; Bernhard Wetterauer; Melanie Distl; Oliver Krohn; Elisabeth Fuss; Hermann Garden; Abdolali Mohagheghzadeh; Eckart Wildi; Peter Ripplinger
Chelation of heavy metals is an important factor in enhancing metal solubility and, hence, metal availability to plants to promote phytoremediation. In the present study, we compared the effects of application of a biodegradable chelating agent, namely, ethylenediaminedisuccinic acid (EDDS) on enhancing plant available form of lead (Pb) in Pb-based paint contaminated residential soils compared to that of a more
A bacterium identified as Pseudomonas fluorescence was isolated from Taxus baccata rhizosphere. Ethyl acetate extract from its culture filtrate yielded an active antimicrobial compound that was purified by TLC. The active metabolites were resolved by column chromatography on silica gel (60-120 mesh). The compound was further characterized on the basis of spectral data (UV, IR and (1)HNMR), which indicated the presence of an aromatic ring and phenolic functionality. The compound showed significant antimicrobial activity against two-gram positive bacteria (B. subtilis and S. aureus), four-gram negative bacteria (E. coli, K. pneumoniae, S. flexneri and P. aeruginosa), and one pathogenic fungus (Candida albicans). The minimum inhibitory concentration (MIC) of the compound ranged between 75?g to 250 ?g/ml. PMID:23100684
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 antimicrobialagents 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 antimicrobialagents (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
The aim of this study was to assess the in vitro activities of nemonoxacin (a novel nonfluorinated quinolone), doripenem, tigecycline, and 16 other antimicrobialagents against Nocardia species. The MICs of the 19 agents against 151 clinical isolates of Nocardia species were determined by the broth microdilution method. The isolates were identified to the species level using 16S rRNA gene sequencing analysis. The results showed that N. brasiliensis (n = 60; 40%) was the most common species, followed by N. cyriacigeorgica (n = 24; 16%), N. farcinica (n = 12; 8%), N. beijingensis (n = 9), N. otitidiscaviarum (n = 8), N. nova (n = 8), N. asiatica (n = 7), N. puris (n = 6), N. flavorosea (n = 5), N. abscessus (n = 3), N. carnea (2), and one each of N. alba, N. asteroides complex, N. rhamnosiphila, N. elegans, N. jinanensis, N. takedensis, and N. transvalensis. The MIC90s of the tested quinolones against the N. brasiliensis isolates were in the order nemonoxacin = gemifloxacin < moxifloxacin < levofloxacin = ciprofloxacin, and the MIC90s of the tested carbapenems were in the order doripenem = meropenem < ertapenem < imipenem. Tigecycline had a lower MIC90 (1 ?g/ml) than linezolid (8 ?g/ml). The MIC90s of the tested quinolones against N. cyriacigeorgica isolates were in the order nemonoxacin < gemifloxacin < moxifloxacin < levofloxacin < ciprofloxacin, and the MIC90s of the tested carbapenems were in the order imipenem < doripenem = meropenem < ertapenem. Nemonoxacin had the lowest MIC90 values among the tested quinolones against the other 17 Nocardia isolates. Among the four tested carbapenems, imipenem had the lowest MIC90s. All of the clinical isolates of N. beijingensis, N. otitidiscaviarum, N. nova, and N. puris and more than half of the N. brasiliensis and N. cyriacigeorgica isolates were resistant to at least one antimicrobialagent. The results of this in vitro study suggest that nemonoxacin, linezolid, and tigecycline are promising treatment options for nocardiosis. Further investigation of their clinical role is warranted.
A series of (2-aminothiazol-4-yl)methylester (5a-t) derivatives were synthesized in good yields and characterized by (1)H NMR, (13)C NMR, mass spectral and elemental analyses. The crystal structure of 5a was evidenced by X-ray diffraction study. The compounds were evaluated for their preliminary in vitro antibacterial, antifungal activity and were screened for antitubercular activity against Mycobacterium tuberculosis H37Rv strain. The synthesized compounds displayed interesting antimicrobial activity. PMID:22280817
Karuvalam, Ranjith P; Haridas, Karickal R; Nayak, Susanta K; Row, Tayur N Guru; Rajeesh, P; Rishikesan, R; Kumari, N Suchetha
Pseudin-2, a naturally occurring 24 amino-acid-residue antimicrobial peptide first isolated from the skin of the South American paradoxical frog Pseudis paradoxa, has weak hemolytic and cytolytic activity but also relatively low potency against microorganisms. In a membrane-mimetic environment, the peptide exists in an amphipathic ?-helical conformation. Analogs of the peptide with increased cationicity and ?-helicity were chemically synthesized by progressively
Tibor Pál; Ágnes Sonnevend; Sehamuddin Galadari; J. Michael Conlon
Synthesis, spectroscopic and biological properties of new bis(3-arylimidazolidinyl-1)methanes are described. These compounds were synthesized by condensation reaction between N-arylethylenediamines and formaldehyde. Chemical structures were confirmed by means of their 1H- and 13C-NMR and mass spectroscopic data. Investigation of in vitro antimicrobial activity was performed using Gram-negative and Gram-positive bacteria as well as antifungal studies against Aspergillus niger and Candida albicans.
Isabel Perillo; Evangelina Repetto; María Cristina Caterina; Rosana Massa; Gabriel Gutkind; Alejandra Salerno