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Sample records for antimicrobial residues agents

  1. Preserving ignitable liquid residues on soil using Triclosan as an anti-microbial agent.

    PubMed

    Turner, Dee A; Goodpaster, John V

    2014-06-01

    When a fire is suspected to be intentionally set, fire debris samples can be collected and analyzed for ignitable liquid residues (ILRs). In some cases, samples will contain highly organic substrates such as soil or rotting wood. These substrates will contain a high bacterial load, which can result in systematic and irreversible damage to the ILR due to microbial degradation. This paper explores ways to preserve ILR by sterilizing fire debris samples without interfering with their subsequent analysis. There are many methods reported in the literature for sterilizing soil, such as freezing, irradiation, autoclaving, and various chemical fumigation techniques. However, these methods either do not kill all bacterial species, cannot be easily applied in the field or would interfere with the analysis of the ILRs. For this work, various anti-microbial compounds including triclosan (2,4,4'-trichloro-2'-hydroxydiphenyl ether) were tested for their efficacy at killing bacteria present in the soil. Triclosan was highly effective in qualitative growth studies and was therefore used to measure bacterial growth (or lack thereof) by spectroscopic analysis as well as passive headspace analysis. These experiments showed that triclosan was able to sterilize soil samples in less than 60s, maintain their sterility for at least 77h and preserve gasoline residues on a soil matrix for at least 30 days.

  2. Polyphenols as antimicrobial agents.

    PubMed

    Daglia, Maria

    2012-04-01

    Polyphenols are secondary metabolites produced by higher plants, which play multiple essential roles in plant physiology and have potential healthy properties on human organism, mainly as antioxidants, anti-allergic, anti-inflammatory, anticancer, antihypertensive, and antimicrobial agents. In the present review the antibacterial, antiviral, and antifungal activities of the most active polyphenol classes are reported, highlighting, where investigated, the mechanisms of action and the structure-activity relationship. Moreover, considering that the microbial resistance has become an increasing global problem, and there is a compulsory need to find out new potent antimicrobial agents as accessories to antibiotic therapy, the synergistic effect of polyphenols in combination with conventional antimicrobial agents against clinical multidrug-resistant microorganisms is discussed.

  3. Peptide Antimicrobial Agents

    PubMed Central

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

    2006-01-01

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

  4. Fluoroquinolone antimicrobial agents.

    PubMed Central

    Wolfson, J S; Hooper, D C

    1989-01-01

    The fluoroquinolones, a new class of potent orally absorbed antimicrobial agents, are reviewed, considering structure, mechanisms of action and resistance, spectrum, variables affecting activity in vitro, pharmacokinetic properties, clinical efficacy, emergence of resistance, and tolerability. The primary bacterial target is the enzyme deoxyribonucleic acid gyrase. Bacterial resistance occurs by chromosomal mutations altering deoxyribonucleic acid gyrase and decreasing drug permeation. The drugs are bactericidal and potent in vitro against members of the family Enterobacteriaceae, Haemophilus spp., and Neisseria spp., have good activity against Pseudomonas aeruginosa and staphylococci, and (with several exceptions) are less potent against streptococci and have fair to poor activity against anaerobic species. Potency in vitro decreases in the presence of low pH, magnesium ions, or urine but is little affected by different media, increased inoculum, or serum. The effects of the drugs in combination with a beta-lactam or aminoglycoside are often additive, occasionally synergistic, and rarely antagonistic. The agents are orally absorbed, require at most twice-daily dosing, and achieve high concentrations in urine, feces, and kidney and good concentrations in lung, bone, prostate, and other tissues. The drugs are efficacious in treatment of a variety of bacterial infections, including uncomplicated and complicated urinary tract infections, bacterial gastroenteritis, and gonorrhea, and show promise for therapy of prostatitis, respiratory tract infections, osteomyelitis, and cutaneous infections, particularly when caused by aerobic gram-negative bacilli. Fluoroquinolones have also proved to be efficacious for prophylaxis against travelers' diarrhea and infection with gram-negative bacilli in neutropenic patients. The drugs are effective in eliminating carriage of Neisseria meningitidis. Patient tolerability appears acceptable, with gastrointestinal or central nervous

  5. Pharmacogenomics of antimicrobial agents

    PubMed Central

    Aung, Ar Kar; Haas, David W; Hulgan, Todd; Phillips, Elizabeth J

    2015-01-01

    Antimicrobial efficacy and toxicity varies between individuals owing to multiple factors. Genetic variants that affect drug-metabolizing enzymes may influence antimicrobial pharmacokinetics and pharmacodynamics, thereby determining efficacy and/or toxicity. In addition, many severe immune-mediated reactions have been associated with HLA class I and class II genes. In the last two decades, understanding of pharmacogenomic factors that influence antimicrobial efficacy and toxicity has rapidly evolved, leading to translational success such as the routine use of HLA-B*57:01 screening to prevent abacavir hypersensitivity reactions. This article examines recent advances in the field of antimicrobial pharmacogenomics that potentially affect treatment efficacy and toxicity, and challenges that exist between pharmacogenomic discovery and translation into clinical use. PMID:25495412

  6. Investigational Antimicrobial Agents of 2013

    PubMed Central

    Pucci, Michael J.

    2013-01-01

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

  7. Ruthenium complexes as antimicrobial agents.

    PubMed

    Li, Fangfei; Collins, J Grant; Keene, F Richard

    2015-04-21

    One of the major advances in medical science has been the development of antimicrobials; however, a consequence of their widespread use has been the emergence of drug-resistant populations of microorganisms. There is clearly a need for the development of new antimicrobials--but more importantly, there is the need for the development of new classes of antimicrobials, rather than drugs based upon analogues of known scaffolds. Due to the success of the platinum anticancer agents, there has been considerable interest in the development of therapeutic agents based upon other transition metals--and in particular ruthenium(II/III) complexes, due to their well known interaction with DNA. There have been many studies of the anticancer properties and cellular localisation of a range of ruthenium complexes in eukaryotic cells over the last decade. However, only very recently has there been significant interest in their antimicrobial properties. This review highlights the types of ruthenium complexes that have exhibited significant antimicrobial activity and discusses the relationship between chemical structure and biological processing--including site(s) of intracellular accumulation--of the ruthenium complexes in both bacterial and eukaryotic cells.

  8. Plant Products as Antimicrobial Agents

    PubMed Central

    Cowan, Marjorie Murphy

    1999-01-01

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

  9. Biodegradable nanoparticles for intracellular delivery of antimicrobial agents.

    PubMed

    Xie, Shuyu; Tao, Yanfei; Pan, Yuanhu; Qu, Wei; Cheng, Guyue; Huang, Lingli; Chen, Dongmei; Wang, Xu; Liu, Zhenli; Yuan, Zonghui

    2014-08-10

    Biodegradable nanoparticles have emerged as a promising strategy for ferrying antimicrobial agents into specific cells due to their unique properties. This review discusses the current progress and challenges of biodegradable nanoparticles for intracellular antimicrobial delivery to understand design principles for the development of ideal nanocarriers. The intracellular delivery performances of biodegradable nanoparticles for diverse antimicrobial agents are first summarized. Second, the cellular internalization and intracellular trafficking, degradation and release kinetics of nanoparticles as well as their relation with intracellular delivery of encapsulated antimicrobial agents are provided. Third, the influences of nanoparticle properties on the cellular internalization and intracellular fate of nanoparticles and their payload antimicrobial agents are discussed. Finally, the challenges and perspectives of nanoparticles for intracellular delivery of antimicrobial agents are addressed. The review will be helpful to the scientists who are interested in searching for more efficient nanosystem strategies for intracellular delivery of antimicrobial agents.

  10. Bdellovibrio bacteriovorus : A future antimicrobial agent?

    PubMed

    Harini, K; Ajila, Vidya; Hegde, Shruthi

    2013-11-01

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

  11. Repurposing celecoxib as a topical antimicrobial agent

    PubMed Central

    Thangamani, Shankar; Younis, Waleed; Seleem, Mohamed N.

    2015-01-01

    There is an urgent need for new antibiotics and alternative strategies to combat multidrug-resistant bacterial pathogens, which are a growing clinical issue. Repurposing existing approved drugs with known pharmacology and toxicology is an alternative strategy to accelerate antimicrobial research and development. In this study, we show that celecoxib, a marketed inhibitor of cyclooxygenase-2, exhibits broad-spectrum antimicrobial activity against Gram-positive pathogens from a variety of genera, including Staphylococcus, Streptococcus, Listeria, Bacillus, and Mycobacterium, but not against Gram-negative pathogens. However, celecoxib is active against all of the Gram-negative bacteria tested, including strains of, Acinetobacter, and Pseudomonas, when their intrinsic resistance is artificially compromised by outer membrane permeabilizing agents such as colistin. The effect of celecoxib on incorporation of radioactive precursors into macromolecules in Staphylococcus aureus was examined. The primary antimicrobial mechanism of action of celecoxib was the dose-dependent inhibition of RNA, DNA, and protein synthesis. Further, we demonstrate the in vivo efficacy of celecoxib in a methicillin-resistant S. aureus (MRSA) infected Caenorhabditis elegans whole animal model. Topical application of celecoxib (1 and 2%) significantly reduced the mean bacterial count in a mouse model of MRSA skin infection. Further, celecoxib decreased the levels of all inflammatory cytokines tested, including tumor necrosis factor-α, interleukin-6, interleukin-1 beta, and monocyte chemo attractant protein-1 in wounds caused by MRSA infection. Celecoxib also exhibited synergy with many conventional antimicrobials when tested against four clinical isolates of S. aureus. Collectively, these results demonstrate that celecoxib alone, or in combination with traditional antimicrobials, has a potential to use as a topical drug for the treatment of bacterial skin infections. PMID:26284040

  12. Synthetic cationic amphiphilic α-helical peptides as antimicrobial agents.

    PubMed

    Wiradharma, Nikken; Khoe, Ulung; Hauser, Charlotte A E; Seow, See Voon; Zhang, Shuguang; Yang, Yi-Yan

    2011-03-01

    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 antimicrobial agents for the treatment of drug resistant infections. However, there is also a growing concern that AMPs with a sequence that is too close to the host organism's AMP may inevitably compromise its own natural defense. In this study, we design a series of synthetic (non-natural) short α-helical AMPs to expand the arsenal of the AMP families and to gain further insights on their antimicrobial activities. These cationic and amphiphilic peptides have a general sequence of (XXYY)(n) (X: hydrophobic residue, Y: cationic residue, and n: the number of repeat units), and are designed to mimic the folding behavior of the naturally-occurring α-helical AMPs. The synthetic α-helical AMPs with 3 repeat units, (FFRR)(3), (LLRR)(3), and (LLKK)(3), are found to be more selective towards microbial cells than rat red blood cells, with minimum inhibitory concentration (MIC) values that are more than 10 times lower than their 50% hemolytic concentrations (HC(50)). They are effective against Gram-positive B. subtilis and yeast C. albicans; and the studies using scanning electron microscopy (SEM) have elucidated that these peptides possess membrane-lytic activities against microbial cells. Furthermore, non-specific immune stimulation assays of a typical peptide shows negligible IFN-α, IFN-γ, and TNF-α inductions in human peripheral blood mononuclear cells, which implies additional safety aspects of the peptide for both systemic and topical use. Therefore, the peptides designed in this study can be promising antimicrobial agents against the frequently-encountered Gram-positive bacteria- or yeast-induced infections.

  13. Discovery and development of new antimicrobial agents.

    PubMed Central

    Gootz, T D

    1990-01-01

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

  14. Antiendotoxin activity of cationic peptide antimicrobial agents.

    PubMed

    Gough, M; Hancock, R E; Kelly, N M

    1996-12-01

    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 antimicrobial agents 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.

  15. Antiendotoxin activity of cationic peptide antimicrobial agents.

    PubMed Central

    Gough, M; Hancock, R E; Kelly, N M

    1996-01-01

    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 antimicrobial agents 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. PMID:8945527

  16. Prodigiosin - A Multifaceted Escherichia coli Antimicrobial Agent

    PubMed Central

    Zorec, Maša; Stopar, David

    2016-01-01

    Despite a considerable interest in prodigiosin, the mechanism of its antibacterial activity is still poorly understood. In this work, Escherichia coli cells were treated with prodigiosin to determine its antimicrobial effect on bacterial physiology. The effect of prodigiosin was concentration dependent. In prodigiosin treated cells above MIC value no significant DNA damage or cytoplasmic membrane disintegration was observed. The outer membrane, however, becomes leaky. Cells had severely decreased respiration activity. In prodigiosin treated cells protein and RNA synthesis were inhibited, cells were elongated but could not divide. Pre-treatment with prodigiosin improved E. coli survival rate in media containing ampicillin, kanamycin and erythromycin but not phleomycin. The results suggest that prodigiosin acts as a bacteriostatic agent in E. coli cells. If prodigiosin was diluted, cells resumed growth. The results indicate that prodigiosin has distinct mode of antibacterial action in different bacteria. PMID:27612193

  17. Antimicrobial peptides: Possible anti-infective agents.

    PubMed

    Lakshmaiah Narayana, Jayaram; Chen, Jyh-Yih

    2015-10-01

    Multidrug-resistant bacterial, fungal, viral, and parasitic infections are major health threats. The Infectious Diseases Society of America has expressed concern on the decrease of pharmaceutical companies working on antibiotic research and development. However, small companies, along with academic research institutes, are stepping forward to develop novel therapeutic methods to overcome the present healthcare situation. Among the leading alternatives to current drugs are antimicrobial peptides (AMPs), which are abundantly distributed in nature. AMPs exhibit broad-spectrum activity against a wide variety of bacteria, fungi, viruses, and parasites, and even cancerous cells. They also show potential immunomodulatory properties, and are highly responsive to infectious agents and innate immuno-stimulatory molecules. In recent years, many AMPs have undergone or are undergoing clinical development, and a few are commercially available for topical and other applications. In this review, we outline selected anion and cationic AMPs which are at various stages of development, from preliminary analysis to clinical drug development. Moreover, we also consider current production methods and delivery tools for AMPs, which must be improved for the effective use of these agents.

  18. Activity of 10 antimicrobial agents against intracellular Rhodococcus equi.

    PubMed

    Giguère, Steeve; Berghaus, Londa J; Lee, Elise A

    2015-08-05

    Studies with facultative intracellular bacterial pathogens have shown that evaluation of the bactericidal activity of antimicrobial agents against intracellular bacteria is more closely associated with in vivo efficacy than traditional in vitro susceptibility testing. The objective of this study was to determine the relative activity of 10 antimicrobial agents against intracellular Rhodococcus equi. Equine monocyte-derived macrophages were infected with virulent R. equi and exposed to erythromycin, clarithromycin, azithromycin, rifampin, ceftiofur, gentamicin, enrofloxacin, vancomycin, imipenem, or doxycycline at concentrations achievable in plasma at clinically recommended dosages in foals. The number of intracellular R. equi was determined 48h after infection by counting colony forming units (CFUs). The number of R. equi CFUs in untreated control wells were significantly higher than those of monolayers treated with antimicrobial agents. Numbers of R. equi were significantly lower in monolayers treated with enrofloxacin followed by those treated with gentamicin, and vancomycin, when compared to monolayers treated with other antimicrobial agents. Numbers of R. equi in monolayers treated with doxycycline were significantly higher than those of monolayers treated with other antimicrobial agents. Differences in R. equi CFUs between monolayers treated with other antimicrobial agents were not statistically significant. Enrofloxacin, gentamicin, and vancomycin are the most active drugs in equine monocyte-derived macrophages infected with R. equi. Additional studies will be needed to determine if these findings correlate with in vivo efficacy.

  19. The Three Bacterial Lines of Defense against Antimicrobial Agents.

    PubMed

    Zhou, Gang; Shi, Qing-Shan; Huang, Xiao-Mo; Xie, Xiao-Bao

    2015-09-09

    Antimicrobial agents target a range of extra- and/or intracellular loci from cytoplasmic wall to membrane, intracellular enzymes and genetic materials. Meanwhile, many resistance mechanisms employed by bacteria to counter antimicrobial agents have been found and reported in the past decades. Based on their spatially distinct sites of action and distribution of location, antimicrobial resistance mechanisms of bacteria were categorized into three groups, coined the three lines of bacterial defense in this review. The first line of defense is biofilms, which can be formed by most bacteria to overcome the action of antimicrobial agents. In addition, some other bacteria employ the second line of defense, the cell wall, cell membrane, and encased efflux pumps. When antimicrobial agents permeate the first two lines of defense and finally reach the cytoplasm, many bacteria will make use of the third line of defense, including alterations of intracellular materials and gene regulation to protect themselves from harm by bactericides. The presented three lines of defense theory will help us to understand the bacterial resistance mechanisms against antimicrobial agents and design efficient strategies to overcome these resistances.

  20. The Three Bacterial Lines of Defense against Antimicrobial Agents

    PubMed Central

    Zhou, Gang; Shi, Qing-Shan; Huang, Xiao-Mo; Xie, Xiao-Bao

    2015-01-01

    Antimicrobial agents target a range of extra- and/or intracellular loci from cytoplasmic wall to membrane, intracellular enzymes and genetic materials. Meanwhile, many resistance mechanisms employed by bacteria to counter antimicrobial agents have been found and reported in the past decades. Based on their spatially distinct sites of action and distribution of location, antimicrobial resistance mechanisms of bacteria were categorized into three groups, coined the three lines of bacterial defense in this review. The first line of defense is biofilms, which can be formed by most bacteria to overcome the action of antimicrobial agents. In addition, some other bacteria employ the second line of defense, the cell wall, cell membrane, and encased efflux pumps. When antimicrobial agents permeate the first two lines of defense and finally reach the cytoplasm, many bacteria will make use of the third line of defense, including alterations of intracellular materials and gene regulation to protect themselves from harm by bactericides. The presented three lines of defense theory will help us to understand the bacterial resistance mechanisms against antimicrobial agents and design efficient strategies to overcome these resistances. PMID:26370986

  1. Thioridazine: resurrection as an antimicrobial agent?

    PubMed Central

    Thanacoody, H K R

    2007-01-01

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

  2. Amino acid–based surfactants: New antimicrobial agents.

    PubMed

    Pinazo, A; Manresa, M A; Marques, A M; Bustelo, M; Espuny, M J; Pérez, L

    2016-02-01

    The rapid increase of drug resistant bacteria makes necessary the development of new antimicrobial agents. Synthetic amino acid-based surfactants constitute a promising alternative to conventional antimicrobial compounds given that they can be prepared from renewable raw materials. In this review, we discuss the structural features that promote antimicrobial activity of amino acid-based surfactants. Monocatenary, dicatenary and gemini surfactants that contain different amino acids on the polar head and show activity against bacteria are revised. The synthesis and basic physico-chemical properties have also been included.

  3. [National multicenter survey: the use of intravenous antimicrobial agents].

    PubMed

    Gutiérrez Zufiaurre, M N; García-Rodríguez, J A

    2006-12-01

    Infectious diseases are currently one of the major health problems worldwide. As a consequence, both nosocomial and community-acquired infections are responsible for a significant increase in workload and health costs for hospitals, particularly in Intensive Care Units (ICU), Internal Medicine and Surgery. The use of intravenous antimicrobial agents is common in hospitalized patients. In order to determine the use of antimicrobial agents and the most frequent procedures used for their administration in Spanish hospitals, a national multicenter survey was undertaken among ICU, Internal Medicine and Surgery health staff from 63 hospitals, in which data were collected on central and peripheral catheter manipulation and intravenous administration. Results showed that, in Spain, both catheter manipulation (insertion, maintenance and removal) and administration of antimicrobial agents are performed by the nursing staff following established protocols, particularly for central catheters. Moreover, the ICUs had the highest rates of catheter-bearing patients, as well as patients undergoing antimicrobial treatment, sometimes in combination. The use of intravenous antimicrobial agents in Spanish hospitals results in an increased workload for the nursing staff and higher health costs, not to mention the risk involved with the use of vascular catheters.

  4. Antimicrobial Peptides Derived from Fusion Peptides of Influenza A Viruses, a Promising Approach to Designing Potent Antimicrobial Agents.

    PubMed

    Wang, Jingyu; Zhong, Wenjing; Lin, Dongguo; Xia, Fan; Wu, Wenjiao; Zhang, Heyuan; Lv, Lin; Liu, Shuwen; He, Jian

    2015-10-01

    The emergence and dissemination of antibiotic-resistant bacterial pathogens have spurred the urgent need to develop novel antimicrobial agents with different mode of action. In this respect, we turned several fusogenic peptides (FPs) derived from the hemagglutinin glycoproteins (HAs) of IAV into potent antibacterials by replacing the negatively or neutrally charged residues of FPs with positively charged lysines. Their antibacterial activities were evaluated by testing the MICs against a panel of bacterial strains including S. aureus, S. mutans, P. aeruginosa, and E. coli. The results showed that peptides HA-FP-1, HA-FP-2-1, and HA-FP-3-1 were effective against both Gram-positive and Gram-negative bacteria with MICs ranging from 1.9 to 16.0 μm, while the toxicities toward mammalian cells were low. In addition, the mode of action and the secondary structure of these peptides were also discussed. These data not only provide several potent peptides displaying promising potential in development as broad antimicrobial agents, but also present a useful strategy in designing new antimicrobial agents.

  5. Mushrooms as Possible Antioxidant and Antimicrobial Agents

    PubMed Central

    Kosanić, Marijana; Ranković, Branislav; Dašić, Marko

    2012-01-01

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

  6. Pyridinium Oxime Compounds as Antimicrobial Agents

    DTIC Science & Technology

    2007-08-01

    and 15 structural analogues have been examined for their antimicrobial properties against a series of model organisms: Bacillus cereus and B...structuraux contre une s~rie d’organismes d𔄀talonnage : Bacillus cereus et B. ant hracis Sterne (comme mod&les pour B. anthracis virulent), Ochrobactrum...pathogens. Bacillus cereus and B. anthracis Sterne were used as models for virulent B. anthracis, Ochrobactrum intermedium as a model for Brucella spp

  7. Silanols, a New Class of Antimicrobial Agent

    DTIC Science & Technology

    2006-04-01

    1964; 86: 1616–1626. [2] Hansch C, Hoekman D, Leo A, Zhang LT, Li P, "The Expanding Role of Quantitative Structure–Activity Relationships ( QSAR ) in... Toxicology ." Toxicol Lett 1995; 79: 45–53. [3] Daoud NN, Dickinson NA, Gilbert P, "Anti-Microbial Activity and Physicochemical Properties of Some...Gram-Positive and Gram-Negative Cells." J Med Chem 1968; 11: 430–441. [9] Kubinyi H, QSAR : Hansch Analysis and Related Approaches. New York: VCH

  8. The In Vitro Antimicrobial Effects of Lavandula angustifolia Essential Oil in Combination with Conventional Antimicrobial Agents

    PubMed Central

    de Rapper, Stephanie; Viljoen, Alvaro

    2016-01-01

    The paper focuses on the in vitro antimicrobial activity of Lavandula angustifolia Mill. (lavender) essential oil in combination with four commercial antimicrobial agents. Stock solutions of chloramphenicol, ciprofloxacin, nystatin, and fusidic acid were tested in combination with L. angustifolia essential oil. The antimicrobial activities of the combinations were investigated against the Gram-positive bacterial strain Staphylococcus aureus (ATCC 6538) and Gram-negative Pseudomonas aeruginosa (ATCC 27858) and Candida albicans (ATCC 10231) was selected to represent the yeasts. The antimicrobial effect was performed using the minimum inhibitory concentration (MIC) microdilution assay. Isobolograms were constructed for varying ratios. The most prominent interaction was noted when L. angustifolia essential oil was combined with chloramphenicol and tested against the pathogen P. aeruginosa (ΣFIC of 0.29). Lavendula angustifolia essential oil was shown in most cases to interact synergistically with conventional antimicrobials when combined in ratios where higher volumes of L. angustifolia essential oil were incorporated into the combination. PMID:27891157

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

    PubMed Central

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

    2013-01-01

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

  10. Plant Antimicrobial Peptides as Potential Anticancer Agents

    PubMed Central

    Guzmán-Rodríguez, Jaquelina Julia; López-Gómez, Rodolfo

    2015-01-01

    Antimicrobial peptides (AMPs) are part of the innate immune defense mechanism of many organisms and are promising candidates to treat infections caused by pathogenic bacteria to animals and humans. AMPs also display anticancer activities because of their ability to inactivate a wide range of cancer cells. Cancer remains a cause of high morbidity and mortality worldwide. Therefore, the development of methods for its control is desirable. Attractive alternatives include plant AMP thionins, defensins, and cyclotides, which have anticancer activities. Here, we provide an overview of plant AMPs anticancer activities, with an emphasis on their mode of action, their selectivity, and their efficacy. PMID:25815333

  11. Pharmacological interactions of anti-microbial agents in odontology.

    PubMed

    Gómez-Moreno, Gerardo; Guardia, Javier; Cutando, Antonio; Calvo-Guirado, José-Luis

    2009-03-01

    In this third article we describe the pharmacological interactions resulting from the use of anti-microbial agents. Although the antimicrobials prescribed in odontology are generally safe they can produce interactions with other medicaments which can give rise to serious adverse reactions which are well documented in clinical studies. Antibiotics with grave and dangerous life threatening consequences are erythromycin, clarithromycin and metronidazol and the anti-fungal agents are ketoconazol and itraconazol. Regarding the capacity of the anti-microbials to reduce the efficacy of oral anti-contraceptives the clinical studies to date are inconclusive, however, it would be prudent for the oral cavity specialist to point out the risk of a possible interaction. Therefore the specialist should be aware of possible interactions as a consequence of administering an antibiotic together with other medicaments the patient may be taking.

  12. In vitro susceptibilities of Mycobacterium tuberculosis to 10 antimicrobial agents.

    PubMed Central

    Byrne, S K; Crawford, C E; Geddes, G L; Black, W A

    1988-01-01

    After preliminary in vitro screening of 10 antimicrobial agents against Mycobacterium tuberculosis, the MICs of the 6 most promising agents against 27 clinical isolates were determined by agar dilution. The two quinolone compounds tested (difloxacin and A-56620) were the most active, each inhibiting 50% of the strains at concentrations of 4 micrograms/ml. M. tuberculosis strains previously shown to be resistant to isoniazid, streptomycin, rifampin, or ethambutol were as susceptible to these quinolone compounds as susceptible strains. PMID:3143305

  13. Susceptibilities of Yersinia pestis strains to 12 antimicrobial agents.

    PubMed

    Wong, J D; Barash, J R; Sandfort, R F; Janda, J M

    2000-07-01

    Ninety-two strains of Yersinia pestis recovered over a 21-year period were evaluated for susceptibility to traditional and newer antimicrobial agents. In vitro resistance was noted only against rifampin and imipenem (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.

  14. Antimicrobial agents deriving from indigenous plants.

    PubMed

    Avrelija, Cencic; Walter, Chingwaru

    2010-01-01

    Phytonutrients in many indigenous plants are receiving a lot of attention as they are important in antimicrobial and anticancer therapies. Tropical areas, especially India, South America and Africa, are the main sources of patentable plant products and have indigenous populations with well developed traditional medicinal knowledge. Phytochemicals, including carotenoids, phenolics, alkaloids, nitrogen-containing compounds, and organosulfur compounds, are receiving much attention as they impart important health benefits. This article gives an insight into some important phytochemicals, and analyses the ethical issues on property rights of plant products. Many patent applications have been lodged, and quite a number have been granted. Pharmaceutical industries are engaging in massive speculative bioprospecting on plant based phytochemicals and products, usually resulting in conflicts with indigenous populations. More focus is given here-in to Tylosema esculentum (marama) plant, found in drier parts of Southern Africa and known to contain high quantities of essential phytochemicals. Important phytochemicals in marama include fatty acid (mainly oleic acid, linoleic acid, linolenic acid, behenic acid), protein and phenolic acid components. The marama plant has high potential as a source of medical and cosmetic products. If conflicts surrounding property rights on plant based products are resolved, phytochemicals can be a good source of income for indigenous populations in areas where such plants are found.

  15. Design of potent fluoro-substituted chalcones as antimicrobial agents.

    PubMed

    Burmaoglu, Serdar; Algul, Oztekin; Gobek, Arzu; Aktas Anil, Derya; Ulger, Mahmut; Erturk, Busra Gul; Kaplan, Engin; Dogen, Aylin; Aslan, Gönül

    2017-12-01

    Owing to ever-increasing bacterial and fungal drug resistance, we attempted to develop novel antitubercular and antimicrobial agents. For this purpose, we developed some new fluorine-substituted chalcone analogs (3, 4, 9-15, and 20-23) using a structure-activity relationship approach. Target compounds were evaluated for their antitubercular efficacy against Mycobacterium tuberculosis H37Rv and antimicrobial activity against five common pathogenic bacterial and three common fungal strains. Three derivatives (3, 9, and 10) displayed significant antitubercular activity with IC50 values of ≤16,760. Compounds derived from trimethoxy substituent scaffolds with monofluoro substitution on the B ring of the chalcone structure exhibited superior inhibition activity compared to corresponding hydroxy analogs. In terms of antimicrobial activity, most compounds (3, 9, 12-14, and 23) exhibited moderate to potent activity against the bacteria, and the antifungal activities of compounds 3, 13, 15, 20, and 22 were comparable to those of reference drugs ampicillin and fluconazole.

  16. In vitro antimicrobial activity of peroxide-based bleaching agents.

    PubMed

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

    2007-06-01

    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.

  17. Supramolecular reactive sulphur nanoparticles: a novel and efficient antimicrobial agent.

    PubMed

    Roy Choudhury, S; Goswami, A

    2013-01-01

    Antimicrobial resistance continues to be an inexorable threat for the biomedical and biochemical researchers. Despite the novel discoveries in drug designing and delivery, high-throughput screening and surveillance data render the prospects for new antimicrobial agents as bleak as ever. The advent of nanotechnology, however, strengthens pharmacology by offering effective therapeutics to treat this aforementioned problem. Several nanoparticles of the known elements have already been reported for their antimicrobial efficacy. Nanosized fabrication of elemental sulphur with suitable surface modifications offers to retrieve the use of sulphur (man's oldest known ecofriendly microbicide) as a potential antimicrobial agent. Sulphur nanoparticles (SNPs) are effective against both conventionally sulphur-resistant and sulphur-susceptible microbes (fungi and bacteria). Moreover, biocompatible polymers present on the surface of SNPs minimize toxicity during application. Here, we focus on various aspects of physicochemical features of SNPs and their biochemical interactions with microbes. The present review also illustrates the effects of SNPs on plants and animals in terms of cytotoxicity and biocompatibility.

  18. Current and future challenges in the development of antimicrobial agents.

    PubMed

    Rennie, Robert P

    2012-01-01

    Micro-organisms exist to survive. Even in the absence of antimicrobial agents, many have determinants of resistance that may be expressed phenotypically, should the need arise. With the advent of the antibiotic age, as more and more drugs were developed to treat serious infections, micro-organisms (particularly bacteria) rapidly developed resistance determinants to prevent their own demise.The most important determinants of resistance have been in the Gram-positive and Gram-negative bacteria. Among Gram-positive bacteria, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE) and penicillin-resistant Streptococcus pneumoniae (PRSP) have taxed researchers and pharmaceutical companies to develop new agents that are effective against these resistant strains. Among the Gram-negative bacteria, extended-spectrum beta-lactamase (ESBL) enzymes, carbapenemases (CREs) and the so-called amp-C enzymes that may be readily transferred between species of enterobacteriaceae and other facultative species have created multi-drug resistant organisms that are difficult to treat. Other resistance determinants have been seen in other clinically important bacterial species such as Neisseria gonorrhoeae, Clostridium difficile, Haemophilus influenzae and Mycobacterium tuberculosis. These issues have now spread to fungal agents of infection.A variety of modalities have been used to stem the tide of resistance. These include the development of niche compounds that target specific resistance determinants. Other approaches have been to find new targets for antimicrobial activity, use of combination agents that are effective against more than one target in the cell, or new delivery mechanism to maximize the concentration of antimicrobial agents at the site of infection without causing toxicity to the host. It is important that such new modalities have been proved effective for clinical therapy. Animal models and non-mammalian systems have been developed to

  19. Essential oils as natural food antimicrobial agents: a review.

    PubMed

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

    2015-01-01

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

  20. Development of non-natural flavanones as antimicrobial agents.

    PubMed

    Fowler, Zachary L; Shah, Karan; Panepinto, John C; Jacobs, Amy; Koffas, Mattheos A G

    2011-01-01

    With growing concerns over multidrug resistance microorganisms, particularly strains of bacteria and fungi, evolving to become resistant to the antimicrobial agents used against them, the identification of new molecular targets becomes paramount for novel treatment options. Recently, the use of new treatments containing multiple active ingredients has been shown to increase the effectiveness of existing molecules for some infections, often with these added compounds enabling the transport of a toxic molecule into the infecting species. Flavonoids are among the most abundant plant secondary metabolites and have been shown to have natural abilities as microbial deterrents and anti-infection agents in plants. Combining these ideas we first sought to investigate the potency of natural flavonoids in the presence of efflux pump inhibitors to limit Escherichia coli growth. Then we used the natural flavonoid scaffold to synthesize non-natural flavanone molecules and further evaluate their antimicrobial efficacy on Escherichia coli, Bacillus subtilis and the fungal pathogens Cryptococcus neoformans and Aspergillus fumigatus. Of those screened, we identified the synthetic molecule 4-chloro-flavanone as the most potent antimicrobial compound with a MIC value of 70 µg/mL in E. coli when combined with the inhibitor Phe-Arg-ß-naphthylamide, and MICs of 30 µg/mL in S. cerevesiae and 30 µg/mL in C. neoformans when used alone. Through this study we have demonstrated that combinatorial synthesis of non-natural flavonones can identify novel antimicrobial agents with activity against bacteria and fungi but with minimal toxicity to human cells.

  1. The Risk of Some Veterinary Antimicrobial Agents on Public Health Associated with Antimicrobial Resistance and their Molecular Basis

    PubMed Central

    Hao, Haihong; Sander, Pascal; Iqbal, Zahid; Wang, Yulian; Cheng, Guyue; Yuan, Zonghui

    2016-01-01

    The risk of antimicrobial agents used in food-producing animals on public health associated with antimicrobial resistance continues to be a current topic of discussion as related to animal and human public health. In the present review, resistance monitoring data, and risk assessment results of some important antimicrobial agents were cited to elucidate the possible association of antimicrobial use in food animals and antimicrobial resistance in humans. From the selected examples, it was apparent from reviewing the published scientific literature that the ban on use of some antimicrobial agents (e.g., avoparcin, fluoroquinolone, tetracyclines) did not change drug resistance patterns and did not mitigate the intended goal of minimizing antimicrobial resistance. The use of some antimicrobial agents (e.g., virginiamycin, macrolides, and cephalosporins) in food animals may have an impact on the antimicrobial resistance in humans, but it was largely depended on the pattern of drug usage in different geographical regions. The epidemiological characteristics of resistant bacteria were closely related to molecular mechanisms involved in the development, fitness, and transmission of antimicrobial resistance. PMID:27803693

  2. Essential oil nanoemulsions as antimicrobial agents in food.

    PubMed

    Donsì, Francesco; Ferrari, Giovanna

    2016-09-10

    The crescent interest in the use of essential oils (EOs) as natural antimicrobials and preservatives in the food industry has been driven in the last years by the growing consumers' demand for natural products with improved microbial safety, and fresh-like organoleptic properties. Nanoemulsions efficiently contribute to support the use of EOs in foods by increasing their dispersibility in the food areas where microorganisms grow and proliferate, by reducing the impact on the quality attributes of the product, as well as by enhancing their antimicrobial activity. Understanding how nanoemulsions intervene on the mass transfer of EOs to the cell membrane and on the mechanism of antimicrobial action will support the engineering of more effective delivery systems and foster the application of EOs in real food systems. This review focuses on the enabling contribution of nanoemulsions to the use of EOs as natural preservative agents in food, (a) specifically addressing the formulation and fabrication of stable EO nanoemulsions, (b) critically analyzing the reported antimicrobial activity data, both in vitro and in product, to infer the impact of the delivery system on the mechanisms of action of EOs, as well as (c) discussing the regulatory issues associated with their use in food systems.

  3. Alanine-Scanning Mutational Analysis of Durancin GL Reveals Residues Important for Its Antimicrobial Activity.

    PubMed

    Ju, Xingrong; Chen, Xinquan; Du, Lihui; Wu, Xueyou; Liu, Fang; Yuan, Jian

    2015-07-22

    Durancin GL is a novel class IIa bacteriocin with 43 residues produced by Enterococcus durans 41D. This bacteriocin demonstrates narrow inhibition spectrum and potent antimicrobial activity against several Listeria monocytogenes strains, including nisin-resistant L. monocytogenes NR30. A systematic alanine-scanning mutational analysis with site-directed mutagenesis was performed to analyze durancin GL residues important for antimicrobial activity and specificity. Results showed that three mutations lost their antimicrobial activity, ten mutations demonstrated a decreased effect on the activity, and seven mutations exhibited relatively high activity. With regard to inhibitory spectrum, four mutants demonstrated a narrower antimicrobial spectrum than wild-type durancin GL. Another four mutants displayed a broader target cell spectrum and increased potency relative to wild-type durancin GL. These findings broaden our understanding of durancin GL residues important for its antimicrobial activity and contribute to future rational design of variants with increased potency.

  4. Containment of antimicrobial resistance due to use of antimicrobial agents in animals intended for food: WHO perspective.

    PubMed

    Aidara-Kane, A

    2012-04-01

    The use of antimicrobial agents 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 antimicrobial agents and that can therefore be difficult or impossible to cure. Of special concern is resistance to antimicrobial agents 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 antimicrobial agents in food-producing animals. Joint efforts should be made to reduce the inappropriate use of antimicrobial agents (e.g. the use of antimicrobials as growth promoters) and limit the spread of bacteria resistant to antimicrobial agents. 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.

  5. Minimal inhibitory concentrations of antimicrobial agents against Actinobacillus pleuropneumoniae.

    PubMed Central

    Nadeau, M; Larivière, S; Higgins, R; Martineau, G P

    1988-01-01

    Forty-five isolates of Actinobacillus pleuropneumoniae were tested for susceptibility to 12 antimicrobial agents using a microdilution method for the minimal inhibitory concentration determinations. These results confirmed the high prevalence of A. pleuropneumoniae strains resistant to antibiotics as reported earlier using the disc diffusion method (Kirby-Bauer method). While 36% of the isolates were resistant to the penicillins, 47% were resistant to chloramphenicol and 68% were resistant to tetracycline. Minimal inhibitory concentrations for the resistant isolates were approximately 32 times higher than those for the susceptible isolates to the above antibacterial agents. The isolates were in general weakly susceptible or resistant to spectinomycin, lincomycin, tiamulin and spiramycin whereas most of them were susceptible to gentamicin, trimethoprim and erythromycin. The susceptibility pattern was similar throughout the 1980 to 1984 period. The 14 serotype 5 isolates were more resistant to tetracycline but less resistant to chloramphenicol and the penicillins than the 28 serotype 1 isolates. PMID:3167716

  6. Antimicrobials in beekeeping.

    PubMed

    Reybroeck, Wim; Daeseleire, Els; De Brabander, Hubert F; Herman, Lieve

    2012-07-06

    The bee diseases American and European foulbrood and nosemosis can be treated with anti-infectious agents. However, in the EU and the USA the use of these agents in beekeeping is strictly regulated due to the lack of tolerance (e.g. Maximum Residue Limit) for residues of antibiotics and chemotherapeutics in honey. This article reviews the literature dealing with antimicrobials of interest in apiculture, stability of these antimicrobials in honey, and disposition of the antimicrobials in honeybee hives.

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

    PubMed

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

    2012-01-01

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

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

    PubMed

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

    2011-07-01

    Antimicrobial agents are toxic to bacteria by a variety of mechanisms. One mechanism that is very dependent on the lipid composition of the bacterial membrane is the clustering of anionic lipid by cationic antimicrobial agents. Certain species of oligo-acyl-lysine (OAK) antimicrobial agents are particularly effective in clustering anionic lipids in mixtures mimicking the composition of bacterial membranes. The clustering of anionic lipids by certain cationic antimicrobial agents contributes to the anti-bacterial action of these agents. Bacterial membrane lipids are a determining factor, resulting in some species of bacteria being more susceptible than others. In addition, lipids can be used to increase the effectiveness of antimicrobial agents when administered in vivo. Therefore, we review some of the structures in which lipid mixtures can assemble, to more effectively be utilized as antimicrobial delivery systems. We describe in more detail the complexes formed between mixtures of lipids mimicking bacterial membranes and an OAK and their usefulness in synergizing with antibiotics to overcome bacterial multidrug resistance.

  9. Corynebacterium equi: in vitro susceptibility to twenty-six antimicrobial agents.

    PubMed Central

    Woolcock, J B; Mutimer, M D

    1980-01-01

    The minimal concentrations of 26 antimicrobial agents required to inhibit growth of 100 isolates of Corynebacterium equi in vitro have been determined. The most active agents were penicillin G, doxycycline, erythromycin, lincomycin, and the aminoglycosides. PMID:7235683

  10. Effects of treatment with antimicrobial agents on the human colonic microflora

    PubMed Central

    Rafii, Fatemeh; Sutherland, John B; Cerniglia, Carl E

    2008-01-01

    Antimicrobial agents are the most valuable means available for treating bacterial infections. However, the administration of therapeutic doses of antimicrobial agents 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. PMID:19337440

  11. Comparative physiological disposition of two nitrofuran anti-microbial agents.

    PubMed

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

    1986-01-01

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

  12. Antimicrobial Peptides: An Emerging Category of Therapeutic Agents

    PubMed Central

    Mahlapuu, Margit; Håkansson, Joakim; Ringstad, Lovisa; Björn, Camilla

    2016-01-01

    Antimicrobial peptides (AMPs), also known as host defense peptides, are short and generally positively charged peptides found in a wide variety of life forms from microorganisms to humans. Most AMPs have the ability to kill microbial pathogens directly, whereas others act indirectly by modulating the host defense systems. Against a background of rapidly increasing resistance development to conventional antibiotics all over the world, efforts to bring AMPs into clinical use are accelerating. Several AMPs are currently being evaluated in clinical trials as novel anti-infectives, but also as new pharmacological agents to modulate the immune response, promote wound healing, and prevent post-surgical adhesions. In this review, we provide an overview of the biological role, classification, and mode of action of AMPs, discuss the opportunities and challenges to develop these peptides for clinical applications, and review the innovative formulation strategies for application of AMPs. PMID:28083516

  13. Retainment of the antimicrobial agent triclosan in a septic tank.

    PubMed

    Kirjanova, Ala; Rimeika, Mindaugas; Vollertsen, Jes; Nielsen, Asbjørn Haaning

    2014-01-01

    Laboratory experiments were conducted to investigate the fate of the antimicrobial agent triclosan (TCS) in a conventional septic tank. The main mechanism of TCS removal from wastewater was identified to be rapid TCS sorption to suspended particles followed by settling of these particles to the bottom of the septic tank. Sorption to particles was completed within minutes while the settling took several days. Therefore, in a septic tank the removal of TCS from wastewater is mainly determined by the removal of suspended particles by sedimentation. Over 5 days of hydraulic residence time the initial dissolved TCS concentration of 100 μg L(-1) was reduced by 87 ± 8%. During the first 24 hours, 66-86% of all removed TCS was retained, whereas during the remainder of the experiment a slight but steady decrease in TCS concentration was observed. This was most likely caused by TCS diffusion and its subsequent sorption onto the septic sludge.

  14. Nontherapeutic use of antimicrobial agents in animal agriculture: implications for pediatrics.

    PubMed

    Shea, Katherine M

    2004-09-01

    Antimicrobial resistance is widespread. Overuse or misuse of antimicrobial agents in veterinary and human medicine is responsible for increasing the crisis of resistance to antimicrobial agents. The American Academy of Pediatrics, in conjunction with the US Public Health Service, has begun to address this problem by disseminating policies on the judicious use of antimicrobial agents in humans. Between 40% and 80% of the antimicrobial agents used in the United States each year are used in food animals; many are identical or very similar to drugs used in humans. Most of this use involves the addition of low doses of antimicrobial agents to the feed of healthy animals over prolonged periods to promote growth and increase feed efficiency or at a range of doses to prevent disease. These nontherapeutic uses contribute to resistance and create health dangers for humans. This report will describe how antimicrobial agents are used in animal agriculture and review the mechanisms by which such uses contribute to resistance in human pathogens. Although therapeutic use of antimicrobial agents in agriculture clearly contributes to the development of resistance, this report will concentrate on nontherapeutic uses in healthy animals.

  15. Determination of UV filters and antimicrobial agents in environmental water samples.

    PubMed

    Cuderman, Petra; Heath, Ester

    2007-02-01

    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-microbial agents, 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-microbial agents 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)).

  16. Susceptibility of Helicobacter pylori to antimicrobial agents: effect of sulglycotide.

    PubMed

    Piotrowski, J; Murty, V L; Slomiany, A; Slomiany, B L

    1995-03-01

    H. pylori is regarded as a primary etiologic factor in gastric disease and the therapies now include a combination of antimicrobial agents with antiulcer drugs. Here, the effect of a new gastroprotective agent, sulglycotide, on the in vitro anti-H. pylori activity of metronidazole, erythromycin, tetracycline, and amoxycillin was assessed. The assays in the absence of sulglycotide gave MIC value 0.10mg/L for erythromycin, 0.12mg/L for amoxycillin, 0.15mg/L for tetracycline and 14mg/L for metronidazole, while sulglycotide alone gave MIC value of 20mg/L. The sulglycotide at its optimal dose (5mg/L) evoked a 4-fold enhancement in the MIC of amoxycillin, 5-fold in tetracycline, and 8.3-fold in erythromycin, while the MIC of metronidazole improved 3.5-fold at 10mg/L sulglycotide. The results point towards the advantage of combination therapy of sulglycotide and antibiotics for H. pylori eradication.

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

    PubMed Central

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

    2014-01-01

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

  18. [Research on the marketing status of antimicrobial products and the use of antimicrobial agents indicated on product labels from 1991 through 2005].

    PubMed

    Nakashima, Harunobu; Miyano, Naoko; Matsunaga, Ichiro; Nakashima, Naomi; Kaniwa, Masa-aki

    2007-05-01

    To clarify the marketing status of antimicrobial products, descriptions on the labels of commercially available antimicrobial products were investigated from 1991 through 2005, and the results were analyzed using a database system on antimicrobial deodorant agents. A classification table of household antimicrobial products was prepared and revised, based on which target products were reviewed for any changes in the product type. The number of antimicrobial products markedly increased over 3 years starting from 1996, among which there were many products apparently not requiring antimicrobial processing. More recently, in the 2002 and 2004 surveys, while sales of kitchenware and daily necessities decreased, chemical products, baby articles, and articles for pets increased; this poses new problems. To clarify the use of antimicrobial agents in the target products, a 3-step (large, intermediate, small) classification table of antimicrobial agents was also prepared, based on which antimicrobial agents indicated on the product labels were checked. The rate of identifying the agents increased. However, this is because of the increase of chemical products and baby articles, both of which more frequently indicated the ingredient agents on the labels, and the decrease of kitchenware and daily necessities, which less frequently indicated them on the labels. Therefore there has been little change in the actual identification rate. The agents used are characterized by product types: quaternary ammonium salts, metal salts, and organic antimicrobials are commonly used in textiles, plastics, and chemical products, respectively. Since the use of natural organic agents has recently increased, the safety of these agents should be evaluated.

  19. Risk Assessment of Growth Hormones and Antimicrobial Residues in Meat

    PubMed Central

    Jeong, Sang-Hee; Kang, Daejin; Lim, Myung-Woon; Kang, Chang Soo

    2010-01-01

    Growth promoters including hormonal substances and antibiotics are used legally and illegally in food producing animals for the growth promotion of livestock animals. Hormonal substances still under debate in terms of their human health impacts are estradiol-17β, progesterone, testosterone, zeranol, trenbolone, and melengestrol acetate (MGA) . Many of the risk assessment results of natural steroid hormones have presented negligible impacts when they are used under good veterinary practices. For synthetic hormonelike substances, ADIs and MRLs have been established for food safety along with the approval of animal treatment. Small amounts of antibiotics added to feedstuff present growth promotion effects via the prevention of infectious diseases at doses lower than therapeutic dose. The induction of antimicrobial resistant bacteria and the disruption of normal human intestinal flora are major concerns in terms of human health impact. Regulatory guidance such as ADIs and MRLs fully reflect the impact on human gastrointestinal microflora. However, before deciding on any risk management options, risk assessments of antimicrobial resistance require large-scale evidence regarding the relationship between antimicrobial use in food-producing animals and the occurrence of antimicrobial resistance in human pathogens. In this article, the risk profiles of hormonal and antibacterial growth promoters are provided based on recent toxicity and human exposure information, and recommendations for risk management to prevent human health impacts by the use of growth promoters are also presented. PMID:24278538

  20. Nontherapeutic Use of Antimicrobial Agents in Animal Agriculture: Implications for Pediatrics.

    PubMed

    Paulson, Jerome A; Zaoutis, Theoklis E

    2015-12-01

    Antimicrobial resistance is one of the most serious threats to public health globally and threatens our ability to treat infectious diseases. Antimicrobial-resistant infections are associated with increased morbidity, mortality, and health care costs. Infants and children are affected by transmission of susceptible and resistant food zoonotic pathogens through the food supply, direct contact with animals, and environmental pathways. The overuse and misuse of antimicrobial agents in veterinary and human medicine is, in large part, responsible for the emergence of antibiotic resistance. Approximately 80% of the overall tonnage of antimicrobial agents sold in the United States in 2012 was for animal use, and approximately 60% of those agents are considered important for human medicine. Most of the use involves the addition of low doses of antimicrobial agents to the feed of healthy animals over prolonged periods to promote growth and increase feed efficiency or at a range of doses to prevent disease. These nontherapeutic uses contribute to resistance and create new health dangers for humans. This report describes how antimicrobial agents are used in animal agriculture, reviews the mechanisms of how such use contributes to development of resistance, and discusses US and global initiatives to curb the use of antimicrobial agents in agriculture.

  1. Antimicrobial agent resistance in mycobacteria: molecular genetic insights.

    PubMed Central

    Musser, J M

    1995-01-01

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

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

    PubMed Central

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

    2014-01-01

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

  3. Quantitative determination of infinite inhibition concentrations of antimicrobial agents.

    PubMed Central

    Marwan, A G; Nagel, C W

    1986-01-01

    We developed a method to determine the infinite inhibition concentrations (IICs) of antimicrobial agents. This method was based on finding the relative effectiveness of an inhibitor at various concentrations. Benzoic acid and parabens were tested on Saccharomyces bayanus, Hansenula sp., and Pseudomonas fluorescens. The relative effectiveness values of these compounds were established. A plot of the inhibitor concentration versus the reciprocal of relative effectiveness was linear. The chi-axis intercept was the concentration of the inhibitor which gave infinite microbial inhibition. For S. bayanus the IICs were 330, 930, 480, and 220 ppm (330, 930, 480, and 220 ml/liter) for benzoic acid and methyl-, ethyl-, and propylparabens, respectively. For Hansenula sp. the IIC was 180 ppm for benzoic acid. For P. fluorescens the IICs were 1,310, 960, and 670 ppm for methyl-, ethyl-, and propylparabens, respectively. Our results indicated that the IIC is affected by the growth medium. The advantages and applications of this method are discussed. PMID:3083773

  4. The in situ synthesis and application of silver nanoparticles as an antimicrobial agent for cotton fibers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The application of sliver (Ag) as an antimicrobial agent dates back to the 1800s. Silver systems release positively charged silver ions (Ag+), when in aqueous media, that disrupts negatively charged surfaces of bacterial membranes, thus resulting in bacterial death. Its antimicrobial utility is not ...

  5. Short AntiMicrobial Peptides (SAMPs) as a class of extraordinary promising therapeutic agents.

    PubMed

    Ramesh, Suhas; Govender, Thavendran; Kruger, Hendrik G; de la Torre, Beatriz G; Albericio, Fernando

    2016-07-01

    The emergence of multidrug resistant bacteria has a direct impact on global public health because of the reduced potency of existing antibiotics against pathogens. Hence, there is a pressing need for new drugs with different modes of action that can kill microorganisms. Antimicrobial peptides (AMPs) can be regarded as an alternative tool for this purpose because they are proven to have therapeutic effects with broad-spectrum activities. There are some hurdles in using AMPs as clinical candidates such as toxicity, lack of stability and high budgets required for manufacturing. This can be overcome by developing shorter and more easily accessible AMPs, the so-called Short AntiMicrobial Peptides (SAMPs) that contain between two and ten amino acid residues. These are emerging as an attractive class of therapeutic agents with high potential for clinical use and possessing multifunctional activities. In this review we attempted to compile those SAMPs that have exhibited biological properties which are believed to hold promise for the future. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

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

    PubMed

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

    2007-08-01

    The emergence of strains of pathogenic microorganisms with resistance to commonly used antibiotics has necessitated a search for novel types of antimicrobial agents. Many frog species produce amphipathic alpha-helical peptides with broad spectrum antimicrobial activity in the skin but their therapeutic potential is limited by varying degrees of cytolytic activity towards eukaryotic cells. Methods for development of such peptides into anti-infective drugs are illustrated by the example of temporin-1DRa (HFLGTLVNLAK KIL.NH(2)). Studies with model alpha-helical peptides have shown that increase in cationicity promotes antimicrobial activity whereas increases in hydrophobicity, helicity and amphipathicity promote hemolytic activity and loss of selectivity for microorganisms. Analogs of temporin-1DRa in which each amino acid is replaced by L-lysine and D-lysine were synthesized and their cytolytic activities tested against a range of microorganisms and human erythrocytes. Small changes in structure produced marked changes in conformation, as determined by retention time on reversed-phase HPLC, and in biological activity. However, peptides containing the substitutions (Val(7) -->L-Lys), (Thr(5)-->D-Lys) and (Asn(8)-->D-Lys) retained the high solubility and potent, broad spectrum antimicrobial activity of the naturally occurring peptide but were appreciably (up to 10-fold) less hemolytic. In contrast, analogs in which Leu(9) and Ile(13) were replaced by the more hydrophobic cyclohexylglycine residue showed slightly increased antimicrobial potencies (up to 2-fold) but a 4-fold increase in hemolytic activity. The data suggest a strategy of selective increases in cationicity concomitant with decreases in helicity and hydrophobicity in the transformation of naturally-occurring antimicrobial peptides into non-toxic therapeutic agents.

  7. Assessment of antimicrobial usage and residues in commercial chicken eggs from smallholder poultry keepers in Morogoro municipality, Tanzania.

    PubMed

    Nonga, H E; Simon, C; Karimuribo, E D; Mdegela, R H

    2010-08-01

    Occurrence of antimicrobial residues in commercial chicken eggs was determined in Morogoro municipality between January and February 2007. Twenty smallholder farmers were interviewed on the types of antimicrobials, reasons of use and their awareness on antimicrobial withdrawal period. Seventy egg samples were collected for qualitative antimicrobial drug residues analysis by use of agar well diffusion and Delvotest SP assays. It was found that farmers use antimicrobial drugs as prophylaxis and treatment of common chicken diseases namely fowl typhoid (85%), infectious bursa disease (Gumboro) (65%) infectious coryza (65%), collibacilosis (55%), coccidiosis (54%), Newcastle disease (50%), helminthosis (20%) and fowl pox (15%). Antimicrobials accounted for 85% of the drugs commonly used. It was also found that 65% of the farmers treat their chicken themselves. The common drugs were oxytetracycline (75%), egg booster (50%), amprolium (35%), sulphamethoxypyridazine (35%), sulphanilamide (25%), chlortetracyclines (10%), chloramphenicol (10%), sulphadiazine-trimethoprim (20%), duoxycycline (20%), sulphadiazine (25%) and flumequine (10%). Eighty per cent of the farmers had knowledge on antimicrobial withdrawal period sold eggs before withdrawal period and almost 85% were unaware of possible effects of antimicrobial residues in humans. All 70 eggs were positive to antimicrobial residues by Delvotest kit, but 21.4% positive with agar well diffusion test. It was concluded that the presence of antimicrobial residues in table eggs could be of public health significance to the egg consumers in Morogoro municipality.

  8. Covalent modification of a ten-residue cationic antimicrobial peptide with levofloxacin

    NASA Astrophysics Data System (ADS)

    Rodriguez, Carlos; Papanastasiou, Emilios; Juba, Melanie; Bishop, Barney

    2014-09-01

    The rampant spread of antibiotic resistant bacteria has spurred interest in alternative strategies for developing next-generation antibacterial therapies. As such, there has been growing interest in cationic antimicrobial peptides (CAMPs) and their therapeutic applications. Modification of CAMPs via conjugation to auxiliary compounds, including small molecule drugs, is a new approach to developing effective, broad-spectrum antibacterial agents with novel physicochemical properties and versatile antibacterial mechanisms. Here, we’ve explored design parameters for engineering CAMPs conjugated to small molecules with favorable physicochemical and antibacterial properties by covalently affixing a fluoroquinolone antibiotic, levofloxacin, to the ten-residue CAMP Pep-4. Relative to the unmodified Pep-4, the conjugate was found to demonstrate substantially increased antibacterial potency under high salt concentrations. Historically, it has been observed that most CAMPs lose antibacterial effectiveness in such high ionic strength environments, a fact that has presented a challenge to their development as therapeutics. Physicochemical studies revealed that P4LC was more hydrophobic than Pep-4, while mechanistic findings indicated that the conjugate was more effective at disrupting bacterial membrane integrity. Although the inherent antibacterial effect of the incorporated levofloxacin molecules did not appear to be substantially realized in this conjugate, these findings nevertheless suggest that covalent attachment of small molecule antibiotics with favorable physicochemical properties to CAMPs could be a promising strategy for enhancing peptide performance and overall therapeutic potential. These results have broader applicability to the development of future CAMP-antibiotic conjugates for potential therapeutic applications.

  9. Covalent modification of a ten-residue cationic antimicrobial peptide with levofloxacin.

    PubMed

    Rodriguez, Carlos A; Papanastasiou, Emilios A; Juba, Melanie; Bishop, Barney

    2014-01-01

    The rampant spread of antibiotic resistant bacteria has spurred interest in alternative strategies for developing next-generation antibacterial therapies. As such, there has been growing interest in cationic antimicrobial peptides (CAMPs) and their therapeutic applications. Modification of CAMPs via conjugation to auxiliary compounds, including small molecule drugs, is a new approach to developing effective, broad-spectrum antibacterial agents with novel physicochemical properties and versatile antibacterial mechanisms. Here, we've explored design parameters for engineering CAMPs conjugated to small molecules with favorable physicochemical and antibacterial properties by covalently affixing a fluoroquinolone antibiotic, levofloxacin, to the ten-residue CAMP Pep-4. Relative to the unmodified Pep-4, the conjugate was found to demonstrate substantially increased antibacterial potency under high salt concentrations. Historically, it has been observed that most CAMPs lose antibacterial effectiveness in such high ionic strength environments, a fact that has presented a challenge to their development as therapeutics. Physicochemical studies revealed that P4LC was more hydrophobic than Pep-4, while mechanistic findings indicated that the conjugate was more effective at disrupting bacterial membrane integrity. Although the inherent antibacterial effect of the incorporated levofloxacin molecules did not appear to be substantially realized in this conjugate, these findings nevertheless suggest that covalent attachment of small molecule antibiotics with favorable physicochemical properties to CAMPs could be a promising strategy for enhancing peptide performance and overall therapeutic potential. These results have broader applicability to the development of future CAMP-antibiotic conjugates for potential therapeutic applications.

  10. Antimicrobial and antioxidant activities of lignin from residue of corn stover to ethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To improve the economic viability of the biofuel production from biomass resource, a value-added lignin byproduct from this process is increasingly interested. Antioxidant and antimicrobial activities of lignin extracted from residue of corn stover to ethanol production were investigated. The lignin...

  11. Antimicrobial Peptides as Anti-biofilm Agents in Medical Implants.

    PubMed

    Sánchez-Gómez, Susana; Martínez-de-Tejada, Guillermo

    2017-01-01

    Biofilm-associated infections constitute a daunting threat to human health, since these pathologies increase patient mortality and morbidity, resulting in prolonged hospitalization periods and heavy economic losses. Moreover, these infections contribute to the increasing emergence and dissemination of antibiotic resistance in hospitals and in the community. Although biofilm-associated microorganisms can proliferate in healthy tissue, abiotic surfaces like those of medical implants greatly increase the likelihood of biofilm formation in the host. Due to their broad spectrum of bactericidal activity against multi-drug resistant microorganisms including metabolically inactive cells, antimicrobial peptides (AMPs) have great potential as anti-biofilm agents. In fact, a clinically available AMP, polymyxin E (colistin), frequently constitutes the drug of last recourse in biofilm-associated infections (e.g. cystic fibrosis) when resistance to all the other drugs arises. In this article, we outline the main strategies under development to combat biofilm-associated infections with an emphasis in the prevention of microbial colonization of medical implants. These approaches include the use of AMPs both for the development of anti-adhesive surface coatings and to kill biofilm-forming cells either on contact or via controlled release (leaching surfaces). Although in vitro results for all these applications are very encouraging, further research is needed to improve the anti-biofilm activity of these coatings in vivo. The possibility of exploiting the antibiotic potentiating activity of some AMPs and to combine several anti-biofilm mechanisms in tandem targeting the biofilm formation process at different stages is also discussed.

  12. Animals living in polluted environments are potential source of antimicrobials against infectious agents.

    PubMed

    Lee, Simon; Siddiqui, Ruqaiyyah; Khan, Naveed Ahmed

    2012-08-01

    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.

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

    PubMed

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

    2014-01-01

    Routine perioperative intravenous antimicrobial agents are administered as surgical prophylaxis. However, whether balanced ultrafiltration during extracorporeal circulation has substantial effect on the concentration of antimicrobial agents remains unclear. The concentrations of antimicrobial agents in plasma and ultrafiltrate samples were measured in this pseudo-extracorporeal circulation model. Extracorporeal circulation consisted of cardiotomy reservoir, membrane oxygenator, and pediatric arterial line filter. A hemoconcentrator was placed between the arterial purge line and oxygenator venous reservoir. Fresh donor human whole blood was added into the circuit and mixed with Ringer's solution to obtain a final hematocrit of 24-28%. Two kinds of antimicrobial agents, cefotiam (320 mg) and cefmetazole (160 mg), were bolus added into the circuit. After 30 min of extracorporeal circulation, zero-balanced ultrafiltration was initiated and arterial line pressure was maintained at approximately 100 mm Hg with a Hoffman clamp. The rate of ultrafiltration (12 mL/min) was controlled by ultrafiltrate outlet pressure. An identical volume of Plasmalyte A was dripped into the circuit to maintain stable hematocrit during 45 min of experiment. Plasma and ultrafiltrate samples were drawn every 5 min, and concentrations of antimicrobial agents (including cefotiam and cefmetazole) were measured with high performance liquid chromatography. Both antimicrobial agents were detected in ultrafiltrate, demonstrating hemoconcentration may remove antimicrobial agents. The concentrations of plasma antimicrobial agents decreased linearly with the increase of ultrafiltrate volume. At end of balanced ultrafiltration, the concentration of plasma cefotiam was 104.96 ± 44.36 mg/L, which is about 44.38% ± 7.42% of the initial concentration (238.95 ± 101.12 mg/L) (P < 0.001); the concentration of plasma cefmetazole decreased linearly to 25.76 ± 14.78

  14. Methods for detecting residues of cleaning agents during cleaning validation.

    PubMed

    Westman, L; Karlsson, G

    2000-01-01

    Cleaning validation procedures are carried out in order to assure that residues of cleaning agents are within acceptable limits after the cleaning process. Cleaning agents often consist of a mixture of various surfactants which are in a highly diluted state after the water rinsing procedure has been completed. This makes it difficult to find appropriate analytical methods that are sensitive enough to detect the cleaning agents. In addition, it is advantageous for the analytical methods to be simple to perform and to give results quickly. In this study, four different analytical methods are compared: visual detection of foam, pH, conductivity measurements, and analysis of total organic carbon (TOC). TOC was used as a reference method when evaluating the other three potential methods. The analyses were performed on different dilutions of the cleaning agents Vips Neutral, RBS-25, Debisan and Perform. The results demonstrated that the most sensitive method for analysis of Vips Neutral, Debisan and Perform is visual detection of foam, by which it is possible to detect concentrations of cleaning agents down to 10 micrograms/mL. RBS-25 was not detected below 200 micrograms/mL, probably because it is formulated with low-foaming surfactants. TOC analysis is less sensitive but has the advantage of being a quantitative analysis, while visual detection of foam is a semi-quantitative method. Visual detection of foam is easy to perform, gives a quick result, and requires no expensive instrumentation. The sensitivity of each method was found to be dependent upon the type of cleaning agent that was analyzed.

  15. Studies on residue-free decontaminants for chemical warfare agents.

    PubMed

    Wagner, George W

    2015-03-17

    Residue-free decontaminants based on hydrogen peroxide, which decomposes to water and oxygen in the environment, are examined as decontaminants for chemical warfare agents (CWA). For the apparent special case of CWA on concrete, H2O2 alone, without any additives, effectively decontaminates S-2-(diisopropylamino)ethyl O-ethyl methylphosphonothioate (VX), pinacolyl methylphosphorofluoridate (GD), and bis(2-choroethyl) sulfide (HD) in a process thought to involve H2O2 activation by surface-bound carbonates/bicarbonates (known H2O2 activators for CWA decontamination). A plethora of products are formed during the H2O2 decontamination of HD on concrete, and these are characterized by comparison to synthesized authentic compounds. As a potential residue-free decontaminant for surfaces other than concrete (or those lacking adsorbed carbonate/bicarbonate) H2O2 activation for CWA decontamination is feasible using residue-free NH3 and CO2 as demonstrated by reaction studies for VX, GD, and HD in homogeneous solution. Although H2O2/NH3/CO2 ("HPAC") decontaminants are active for CWA decontamination in solution, they require testing on actual surfaces of interest to assess their true efficacy for surface decontamination.

  16. Ethyl Pyruvate: An Anti-Microbial Agent that Selectively Targets Pathobionts and Biofilms

    PubMed Central

    Debebe, Tewodros; Krüger, Monika; Huse, Klaus; Kacza, Johannes; Mühlberg, Katja; König, Brigitte; Birkenmeier, Gerd

    2016-01-01

    The microbiota has a strong influence on health and disease in humans. A causative shift favoring pathobionts is strongly linked to diseases. Therefore, anti-microbial agents selectively targeting potential pathogens as well as their biofilms are urgently demanded. Here we demonstrate the impact of ethyl pyruvate, so far known as ROS scavenger and anti-inflammatory agent, on planktonic microbes and biofilms. Ethyl pyruvate combats preferably the growth of pathobionts belonging to bacteria and fungi independent of the genera and prevailing drug resistance. Surprisingly, this anti-microbial agent preserves symbionts like Lactobacillus species. Moreover, ethyl pyruvate prevents the formation of biofilms and promotes matured biofilms dissolution. This potentially new anti-microbial and anti-biofilm agent could have a tremendous positive impact on human, veterinary medicine and technical industry as well. PMID:27658257

  17. Surveillance of antimicrobial resistance in bacteria isolated from food animals to antimicrobial growth promoters and related therapeutic agents in Denmark.

    PubMed

    Aarestrup, F M; Bager, F; Jensen, N E; Madsen, M; Meyling, A; Wegener, H C

    1998-06-01

    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

  18. IQ-motif peptides as novel anti-microbial agents.

    PubMed

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

    2013-04-01

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

  19. EDTA: An Antimicrobial and Antibiofilm Agent for Use in Wound Care

    PubMed Central

    Finnegan, Simon; Percival, Steven L.

    2015-01-01

    Significance: Methods employed for preventing and eliminating biofilms are limited in their efficacy on mature biofilms. Despite this a number of antibiofilm formulations and technologies incorporating ethylenediaminetetraacetic acid (EDTA) have demonstrated efficacy on in vitro biofilms. The aim of this article is to critically review EDTA, in particular tetrasodium EDTA (tEDTA), as a potential antimicrobial and antibiofilm agent, in its own right, for use in skin and wound care. EDTA's synergism with other antimicrobials and surfactants will also be discussed. Recent Advances: The use of EDTA as a potentiating and sensitizing agent is not a new concept. However, currently the application of EDTA, specifically tEDTA as a stand-alone antimicrobial and antibiofilm agent, and its synergistic combination with other antimicrobials to make a “multi-pronged” approach to biofilm control is being explored. Critical Issues: As pathogenic biofilms in the wound increase infection risk, tEDTA could be considered as a potential “stand-alone” antimicrobial/antibiofilm agent or in combination with other antimicrobials, for use in both the prevention and treatment of biofilms found within abiotic (the wound dressing) and biotic (wound bed) environments. The ability of EDTA to chelate and potentiate the cell walls of bacteria and destabilize biofilms by sequestering calcium, magnesium, zinc, and iron makes it a suitable agent for use in the management of biofilms. Future Direction: tEDTA's excellent inherent antimicrobial and antibiofilm activity and proven synergistic and permeating ability results in a very beneficial agent, which could be used for the development of future antibiofilm technologies. PMID:26155384

  20. Anthocyanins as antimicrobial agents of natural plant origin.

    PubMed

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

    2011-01-01

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

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

    PubMed Central

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

    2009-01-01

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

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

    PubMed

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

    2014-07-01

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

  3. In Vitro Susceptibility of Equine-Obtained Isolates of Corynebacterium pseudotuberculosis to Gallium Maltolate and 20 Other Antimicrobial Agents

    PubMed Central

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

    2014-01-01

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

  4. Assessment of antimicrobial drug residues in beef in Abuja, the Federal Capital Territory, Nigeria.

    PubMed

    Omeiza, Gabriel K; Ajayi, Itopa E; Ode, Okwoche J

    2012-01-01

    Drugs administered to food-producing animals close to the time of slaughter often result in prohibited antimicrobial residues in the animal tissues at slaughter. Evidence based on the Premi® test confirmed the occurrence of antimicrobial drug residues in 89.3% of kidney and urine samples from cattle slaughtered within Abuja town where the residents rely heavily on beef as a source of protein. The administration of antibiotics close to the time of slaughter by marketers/herd owners and transporters was found to be significantly (p<0.05) higher when compared with butchers and abattoir workers. The practice of administering antibiotics to animals close to the time of slaughter was believed to be profit-motivated. The research suggests that awareness campaigns amongst the stakeholders, the enactment of appropriate laws for the control of antibiotic use and the empowerment of veterinary public health practitioners in food regulatory agencies as some of the strategies which may positively reduce the risk of antimicrobial drug residues in food animals in Nigeria.

  5. Antimicrobial residues in animal waste and water resources proximal to large-scale swine and poultry feeding operations

    USGS Publications Warehouse

    Campagnolo, E.R.; Johnson, K.R.; Karpati, A.; Rubin, C.S.; Kolpin, D.W.; Meyer, M.T.; Esteban, J. Emilio; Currier, R.W.; Smith, K.; Thu, K.M.; McGeehin, M.

    2002-01-01

    Expansion and intensification of large-scale animal feeding operations (AFOs) in the United States has resulted in concern about environmental contamination and its potential public health impacts. The objective of this investigation was to obtain background data on a broad profile of antimicrobial residues in animal wastes and surface water and groundwater proximal to large-scale swine and poultry operations. The samples were measured for antimicrobial compounds using both radioimmunoassay and liquid chromatography/electrospray ionization-mass spectrometry (LC/ESI-MS) techniques. Multiple classes of antimicrobial compounds (commonly at concentrations of >100 μg/l) were detected in swine waste storage lagoons. In addition, multiple classes of antimicrobial compounds were detected in surface and groundwater samples collected proximal to the swine and poultry farms. This information indicates that animal waste used as fertilizer for crops may serve as a source of antimicrobial residues for the environment. Further research is required to determine if the levels of antimicrobials detected in this study are of consequence to human and/or environmental ecosystems. A comparison of the radioimmunoassay and LC/ESI-MS analytical methods documented that radioimmunoassay techniques were only appropriate for measuring residues in animal waste samples likely to contain high levels of antimicrobials. More sensitive LC/ESI-MS techniques are required in environmental samples, where low levels of antimicrobial residues are more likely.

  6. pH Dependent Antimicrobial Peptides and Proteins, Their Mechanisms of Action and Potential as Therapeutic Agents.

    PubMed

    Malik, Erum; Dennison, Sarah R; Harris, Frederick; Phoenix, David A

    2016-11-01

    Antimicrobial peptides (AMPs) are potent antibiotics of the innate immune system that have been extensively investigated as a potential solution to the global problem of infectious diseases caused by pathogenic microbes. A group of AMPs that are increasingly being reported are those that utilise pH dependent antimicrobial mechanisms, and here we review research into this area. This review shows that these antimicrobial molecules are produced by a diverse spectrum of creatures, including vertebrates and invertebrates, and are primarily cationic, although a number of anionic examples are known. Some of these molecules exhibit high pH optima for their antimicrobial activity but in most cases, these AMPs show activity against microbes that present low pH optima, which reflects the acidic pH generally found at their sites of action, particularly the skin. The modes of action used by these molecules are based on a number of major structure/function relationships, which include metal ion binding, changes to net charge and conformational plasticity, and primarily involve the protonation of histidine, aspartic acid and glutamic acid residues at low pH. The pH dependent activity of pore forming antimicrobial proteins involves mechanisms that generally differ fundamentally to those used by pH dependent AMPs, which can be described by the carpet, toroidal pore and barrel-stave pore models of membrane interaction. A number of pH dependent AMPs and antimicrobial proteins have been developed for medical purposes and have successfully completed clinical trials, including kappacins, LL-37, histatins and lactoferrin, along with a number of their derivatives. Major examples of the therapeutic application of these antimicrobial molecules include wound healing as well as the treatment of multiple cancers and infections due to viruses, bacteria and fungi. In general, these applications involve topical administration, such as the use of mouth washes, cream formulations and hydrogel

  7. pH Dependent Antimicrobial Peptides and Proteins, Their Mechanisms of Action and Potential as Therapeutic Agents

    PubMed Central

    Malik, Erum; Dennison, Sarah R.; Harris, Frederick; Phoenix, David A.

    2016-01-01

    Antimicrobial peptides (AMPs) are potent antibiotics of the innate immune system that have been extensively investigated as a potential solution to the global problem of infectious diseases caused by pathogenic microbes. A group of AMPs that are increasingly being reported are those that utilise pH dependent antimicrobial mechanisms, and here we review research into this area. This review shows that these antimicrobial molecules are produced by a diverse spectrum of creatures, including vertebrates and invertebrates, and are primarily cationic, although a number of anionic examples are known. Some of these molecules exhibit high pH optima for their antimicrobial activity but in most cases, these AMPs show activity against microbes that present low pH optima, which reflects the acidic pH generally found at their sites of action, particularly the skin. The modes of action used by these molecules are based on a number of major structure/function relationships, which include metal ion binding, changes to net charge and conformational plasticity, and primarily involve the protonation of histidine, aspartic acid and glutamic acid residues at low pH. The pH dependent activity of pore forming antimicrobial proteins involves mechanisms that generally differ fundamentally to those used by pH dependent AMPs, which can be described by the carpet, toroidal pore and barrel-stave pore models of membrane interaction. A number of pH dependent AMPs and antimicrobial proteins have been developed for medical purposes and have successfully completed clinical trials, including kappacins, LL-37, histatins and lactoferrin, along with a number of their derivatives. Major examples of the therapeutic application of these antimicrobial molecules include wound healing as well as the treatment of multiple cancers and infections due to viruses, bacteria and fungi. In general, these applications involve topical administration, such as the use of mouth washes, cream formulations and hydrogel

  8. [In vitro sensitivity of Mycobacterium chelonae strains to various antimicrobial agents].

    PubMed

    Hernández García, A M; Arias, A; Felipe, A; Alvarez, R; Sierra, A

    1995-12-01

    The in vitro susceptibility of 32 Mycobacterium chelonae strains to 10 antimicrobial agents was determined. The sources of the different strains were: clinical samples from patients treated at the Hospital Universitario de Canarias and Hospital del Tórax (General and Chest facilities) and from environmental sources (water supply, sewage, swimming pools and the sea). The susceptibility tests were performed by a broth microdilution method (Mueller-Hinton Broth). The results showed amikacin as the most effective antimicrobial agent against M. chelonae isolates, then ofloxacin and cefoxitin. However no statistical difference was detected among them. The least effective was imipenem, followed by ciprofloxacin and norfloxacin.

  9. Pectin functionalized with natural fatty acids as antimicrobial agent.

    PubMed

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

    2014-07-01

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

  10. Dendrimer-Silver Complexes and Nanocomposites as Antimicrobial Agents

    DTIC Science & Technology

    2001-01-01

    especially important in the topical antibacterial treatment of burn wounds, where transient bacteremia is commonly cited.1 Silver sulfonamides, par...In this test, dendrimer- silver compounds were examined for diffusible antimicrobial activity by placing a 10 µL sample of each solution onto a 6 mm...compound, it does not have visible absorption over 300 nm wavelength. Absorption at longer wavelength is caused by the silver nanoparticles . Spec

  11. Exploring the potential of magnetic antimicrobial agents for water disinfection.

    PubMed

    Pina, Ana S; Batalha, Iris L; Fernandes, Cláudia S M; Aoki, Matheus A; Roque, Ana C A

    2014-12-01

    Industrial and urban activities yield large amounts of contaminated groundwater, which present a major health issue worldwide. Infectious diseases are the most common health risk associated with drinking-water and wastewater remediation is a major concern of our modern society. The field of wastewater treatment is being revolutionized by new nano-scale water disinfection devices which outperform most currently available technologies. In particular, iron oxide magnetic nanoparticles (MNPs) have been widely used in environmental applications due to their unique physical-chemical properties. In this work, poly(ethylene) glycol (PEG)-coated MNPs have been functionalized with (RW)3, an antimicrobial peptide, to yield a novel magnetic-responsive support with antimicrobial activity against Escherichia coli K-12 DSM498 and Bacillus subtilis 168. The magnetic-responsive antimicrobial device showed to be able to successfully disinfect the surrounding solution. Using a rapid high-throughput screening platform, the minimal inhibitory concentration (MIC) was determined to be 500 μM for both strains with a visible bactericidal effect.

  12. Carbon nanodots as molecular scaffolds for development of antimicrobial agents.

    PubMed

    Ngu-Schwemlein, Maria; Chin, Suk Fun; Hileman, Ryan; Drozdowski, Chris; Upchurch, Clint; Hargrove, April

    2016-04-01

    We report the potential of carbon nanodots (CNDs) as a molecular scaffold for enhancing the antimicrobial activities of small dendritic poly(amidoamines) (PAMAM). Carbon nanodots prepared from sago starch are readily functionalized with PAMAM by using N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS). Electron microscopy images of these polyaminated CNDs show that they are approximately 30-60nm in diameter. Infrared and fluorescence spectroscopy analyses of the water-soluble material established the presence of the polyamidoaminated moiety and the intrinsic fluorescence of the nanodots. The polyaminated nanodots (CND-PAM1 and CND-PAM2) exhibit in vitro antimicrobial properties, not only to non-multidrug resistant bacteria but also to the corresponding Gram-negative multidrug bacteria. Their minimum inhibitory concentration (MIC) ranges from 8 to 64μg/mL, which is much lower than that of PAMAM G1 or the non-active PAMAM G0 and CNDs. Additionally, they show synergistic effect in combination with tetracycline or colistin. These preliminary results imply that CNDs can serve as a promising scaffold for facilitating the rational design of antimicrobial materials for combating the ever-increasing threat of antibiotic resistance. Moreover, their fluorescence could be pertinent to unraveling their mode of action for imaging or diagnostic applications.

  13. Global survey on nebulization of antimicrobial agents in mechanically ventilated patients: a call for international guidelines.

    PubMed

    Solé-Lleonart, C; Roberts, J A; Chastre, J; Poulakou, G; Palmer, L B; Blot, S; Felton, T; Bassetti, M; Luyt, C-E; Pereira, J M; Riera, J; Welte, T; Qiu, H; Rouby, J-J; Rello, J

    2016-04-01

    Nebulized antimicrobial agents are increasingly administered for treatment of respiratory infections in mechanically ventilated (MV) patients. A structured online questionnaire assessing the indications, dosages and recent patterns of use for nebulized antimicrobial agents in MV patients was developed. The questionnaire was distributed worldwide and completed by 192 intensive care units. The most common indications for using nebulized antimicrobial agent were ventilator-associated tracheobronchitis (VAT; 58/87), ventilator-associated pneumonia (VAP; 56/87) and management of multidrug-resistant, Gram-negative (67/87) bacilli in the respiratory tract. The most common prescribed nebulized agents were colistin methanesulfonate and sulfate (36/87, 41.3% and 24/87, 27.5%), tobramycin (32/87, 36.7%) and amikacin (23/87, 26.4%). Colistin methanesulfonate, amikacin and tobramycin daily doses for VAP were significantly higher than for VAT (p < 0.05). Combination of parenteral and nebulized antibiotics occurred in 50 (86%) of 58 prescriptions for VAP and 36 (64.2%) of 56 of prescriptions for VAT. The use of nebulized antimicrobial agents in MV patients is common. There is marked heterogeneity in clinical practice, with significantly different in use between patients with VAP and VAT. Randomized controlled clinical trials and international guidance on indications, dosing and antibiotic combinations to improve clinical outcomes are urgently required.

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

    PubMed

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

    2014-02-01

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

  15. Benzofuran as a promising scaffold for the synthesis of antimicrobial and antibreast cancer agents: A review

    PubMed Central

    Khodarahmi, Ghadamali; Asadi, Parvin; Hassanzadeh, Farshid; Khodarahmi, Elham

    2015-01-01

    Benzofuran as an important heterocyclic compound is extensively found in natural products as well as synthetic materials. Since benzofuran drivatives display a diverse array of pharmacological activities, an interest in developing new biologically active agents from benzofuran is still under consideration. This review highlights recent findings on biological activities of benzofuran derivatives as antimicrobial and antibreast cancer agents and lays emphasis on the importance of benzofurans as a major source for drug design and development. PMID:26941815

  16. Evaluating bionanoparticle infused fungal metabolites as a novel antimicrobial agent

    PubMed Central

    Rajpal, Kartikeya; Aziz, Nafe; Prasad, Ram; Varma, Ramendra G.; Varma, Ajit

    2016-01-01

    Therapeutic properties of fungal metabolites and silver nanoparticles have been well documented. While fungal metabolites have been used for centuries as medicinal drugs, potential of biogenic silver nanoparticles has recently received attention. We have evaluated the antimicrobial potential of Aspergillus terreus crude extract, silver nanoparticles and an amalgamation of both against four pathogenic bacterial strains. Antimicrobial activity of the following was evaluated – A. terreus extract, biogenic silver nanoparticles, and a mixture containing extract and nanoparticles. Four pathogenic bacteria - Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, and Bacillus cereus were used as test organisms. Phenol, flavonoid, and alkaloid content of extract were determined to understand the chemical profile of the fungus. The extract contained significantly high amounts of phenols, flavonoids, and alkaloids. The extract and biogenic silver nanoparticle exhibited significant antibacterial activity at concentrations of 10 μg/ml and 1 μg/ml, respectively. When used in combination, the extract-nanoparticle mixture showed equally potent antibacterial activity at a much lower concentration of 2.5 μg/ml extract + 0.5 μg/ml nanoparticle. Given its high antibacterial potential, the fungal extract can be a promising source of novel drug lead compounds. The extract – silver nanoparticle mixture exhibited synergism in their antibacterial efficacy. This property can be further used to formulate new age drugs. PMID:27429931

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

    PubMed

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

    2010-09-08

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

  18. Inhibition of Legionella pneumophila multiplication within human macrophages by antimicrobial agents.

    PubMed Central

    Vildé, J L; Dournon, E; Rajagopalan, P

    1986-01-01

    The activity of serial concentrations of different antimicrobial agents 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 antimicrobial agents 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 antimicrobial agents in experimental infections and in Legionnaires disease. They sustain clinical interest in the new quinolones, such as pefloxacin, and in combinations of antimicrobial agents for the treatment of Legionnaires disease. PMID:3492176

  19. Inhibitory effects of antimicrobial agents against Fusarium species.

    PubMed

    Kawakami, Hideaki; Inuzuka, Hiroko; Hori, Nobuhide; Takahashi, Nobumichi; Ishida, Kyoko; Mochizuki, Kiyofumi; Ohkusu, Kiyofumi; Muraosa, Yasunori; Watanabe, Akira; Kamei, Katsuhiko

    2015-08-01

    We investigated the inhibitory effects of antibacterial, biocidal, and antifungal agents against Fusarium spp. Seven Fusarium spp: four F. falciforme (Fusarium solani species complex), one Fusarium spp, one Fusarium spp. (Fusarium incarnatum-equiseti species complex), and one F. napiforme (Gibberella fujikuroi species complex), isolated from eyes with fungal keratitis were used in this study. Their susceptibility to antibacterial agents: flomoxef, imipenem, gatifloxacin, levofloxacin, moxifloxacin, gentamicin, tobramycin, and Tobracin® (contained 3,000 μg/ml of tobramycin and 25 μg/ml of benzalkonium chloride (BAK), a biocidal agent: BAK, and antifungal agents: amphotericin B, pimaricin (natamycin), fluconazole, itraconazole, miconazole, voriconazole, and micafungin, was determined by broth microdilution tests. The half-maximal inhibitory concentration (IC50), 100% inhibitory concentration (IC100), and minimum inhibitory concentration (MIC) against the Fusarium isolates were determined. BAK had the highest activity against the Fusarium spp. except for the antifungal agents. Three fluoroquinolones and two aminoglycosides had inhibitory effects against the Fusarium spp. at relatively high concentrations. Tobracin® had a higher inhibitory effect against Fusarium spp. than tobramycin alone. Amphotericin B had the highest inhibitory effect against the Fusarium spp, although it had different degrees of activity against each isolate. Our findings showed that fluoroquinolones, aminoglycosides, and BAK had some degree of inhibitory effect against the seven Fusarium isolates, although these agents had considerably lower effect than amphotericin B. However, the inhibitory effects of amphotericin B against the Fusarium spp. varied for the different isolates. Further studies for more effective medications against Fusarium, such as different combinations of antibacterial, biocidal, and antifungal agents are needed.

  20. Essential oils from aromatic herbs as antimicrobial agents.

    PubMed

    Solórzano-Santos, Fortino; Miranda-Novales, Maria Guadalupe

    2012-04-01

    Bacterial resistance to multiple antibiotics is a health problem. Essential oils (EOs) possess antibacterial properties and have been screened as potential sources of novel antimicrobial compounds. Terpenes and terpenoids are components derived from EOs. Some of these EOs show inhibitory activity against Staphylococcus aureus. Carvacrol has specific effects on S. aureus and Staphylococcus epidermidis. Perilla oil suppresses expression of α-toxin, Staphylococcus enterotoxin A and B and toxic shock syndrome toxin. Geraniol shows good activity in modulating drug resistance in several gram-negative species. EOs could act as biopreservatives, reducing or eliminating pathogenic bacteria and increasing the overall quality of animal and vegetable food products. Although clinical studies are scarce, the uses of EOs for topical administration and as penetration enhancers for antiseptics are promising. Little information exists for oral administration.

  1. Antibiotic resistance, antimicrobial residues and bacterial community composition in urban wastewater.

    PubMed

    Novo, Ana; André, Sandra; Viana, Paula; Nunes, Olga C; Manaia, Célia M

    2013-04-01

    This study was based on the hypothesis that the occurrence of antimicrobial residues and antibiotic resistant bacteria in the sewage could be correlated with the structure and composition of the bacterial community and the antibiotic resistance loads of the final effluent. Raw and treated wastewater composite samples were collected from an urban treatment plant over 14 sampling dates. Samples were characterized for the i) occurrence of tetracyclines, penicillins, sulfonamides, quinolones, triclosan, arsenic, cadmium, lead, chromium and mercury; ii) antibiotic resistance percentages for tetracycline, sulfamethoxazole, ciprofloxacin and amoxicillin and iii) 16S rRNA gene-DGGE patterns. The data of corresponding samples, taking into account the hydraulic residence time, was analyzed using multivariate analysis. Variations on the bacterial community structure of the final effluent were significantly correlated with the occurrence of tetracyclines, penicillins, sulfonamides, quinolones and triclosan in the raw inflow. Members of the class Epsilonproteobacteria presented positive correlations with those antimicrobials, whereas negative correlations were observed with Beta and Gammaproteobacteria and Firmicutes. Antibiotic resistance percentages presented different trends of variation in heterotrophs/enterobacteria and in enterococci, varied over time and after wastewater treatment. Antibiotic resistance was positively correlated with the occurrence of tetracyclines residues and high temperature. A relationship between antibiotic residues, bacterial community structure and composition and antibiotic resistance is demonstrated. Further studies, involving more wastewater treatment plants may help to elucidate this complex relationship.

  2. Dairy farm age and resistance to antimicrobial agents in Escherichia coli isolated from dairy topsoil.

    PubMed

    Jones, Suzanna E; Burgos, Jonathan M; Lutnesky, Marvin M F; Sena, Johnny A; Kumar, Sanath; Jones, Lindsay M; Varela, Manuel F

    2011-04-01

    Antimicrobial agent usage is common in animal agriculture for therapeutic and prophylactic purposes. Selective pressure exerted by these antimicrobials on soil bacteria could result in the selection of strains that are resistant due to chromosomal- or plasmid-derived genetic components. Multiple antimicrobial resistances in Escherichia coli and the direct relationship between antimicrobial agent use over time has been extensively studied, yet the relationship between the age of an animal agriculture environment such as a dairy farm and antibiotic resistance remains unclear. Therefore, we tested the hypothesis that antimicrobial-resistance profiles of E. coli isolated from dairy farm topsoil correlate with dairy farm age. E. coli isolated from eleven dairy farms of varying ages within Roosevelt County, NM were used for MIC determinations to chloramphenicol, nalidixic acid, penicillin, tetracycline, ampicillin, amoxicillin/clavulanic acid, gentamicin, trimethoprim/sulfamethoxazole, cefotaxime, and ciprofloxacin. The minimum inhibitory concentration values of four antibiotics ranged 0.75 to >256 μg/ml, 1 to >256 μg/ml, 12 to >256 μg/ml, and 0.75 to >256 μg/ml for chloramphenicol, nalidixic acid, penicillin, and tetracycline, respectively. The study did not show a direct relationship between antibiotic resistance and the age of dairy farms.

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

    PubMed Central

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

    2014-01-01

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

  4. CO-releasing Metal Carbonyl Compounds as Antimicrobial Agents in the Post-antibiotic Era*

    PubMed Central

    Wareham, Lauren K.; Poole, Robert K.; Tinajero-Trejo, Mariana

    2015-01-01

    The possibility of a “post-antibiotic era” in the 21st century, in which common infections may kill, has prompted research into radically new antimicrobials. CO-releasing molecules (CORMs), mostly metal carbonyl compounds, originally developed for therapeutic CO delivery in animals, are potent antimicrobial agents. Certain CORMs inhibit growth and respiration, reduce viability, and release CO to intracellular hemes, as predicted, but their actions are more complex, as revealed by transcriptomic datasets and modeling. Progress is hindered by difficulties in detecting CO release intracellularly, limited understanding of the biological chemistry of CO reactions with non-heme targets, and the cytotoxicity of some CORMs to mammalian cells. PMID:26055702

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

    PubMed Central

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

    1993-01-01

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

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

    PubMed

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

    1993-02-01

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

  7. Self-assembled cationic peptide nanoparticles as an efficient antimicrobial agent

    NASA Astrophysics Data System (ADS)

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

    2009-07-01

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

  8. Potential of medicinal plants as antimicrobial and antioxidant agents in food industry: a hypothesis.

    PubMed

    Ortega-Ramirez, Luis Alberto; Rodriguez-Garcia, Isela; Leyva, Juan Manuel; Cruz-Valenzuela, Manuel Reynaldo; Silva-Espinoza, Brenda Adriana; Gonzalez-Aguilar, Gustavo A; Siddiqui, Wasim; Ayala-Zavala, Jesus Fernando

    2014-02-01

    Many food preservation strategies can be used for the control of microbial spoilage and oxidation; however, these quality problems are not yet controlled adequately. Although synthetic antimicrobial and antioxidant agents are approved in many countries, the use of natural safe and effective preservatives is a demand of food consumers and producers. This paper proposes medicinal plants, traditionally used to treat health disorders and prevent diseases, as a source of bioactive compounds having food additive properties. Medicinal plants are rich in terpenes and phenolic compounds that present antimicrobial and antioxidant properties; in addition, the literature revealed that these bioactive compounds extracted from other plants have been effective in food systems. In this context, the present hypothesis paper states that bioactive molecules extracted from medicinal plants can be used as antimicrobial and antioxidant additives in the food industry.

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

    PubMed

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

    2013-01-01

    The free-living amoeba Balamuthia mandrillaris causes usually fatal encephalitis in humans and animals. Only limited studies have investigated the efficacy of antimicrobial agents against the organism. Assay methods were developed to assess antimicrobial efficacy against both the trophozoite and cyst stage of B. mandrillaris (ATCC 50209). Amphotericin B, ciclopirox olamine, miltefosine, natamycin, paromomycin, pentamidine isethionate, protriptyline, spiramycin, sulconazole and telithromycin had limited activity with amoebacidal levels of > 135-500 μM. However, diminazene aceturate (Berenil(®) ) was amoebacidal at 7.8 μM and 31.3-61.5 μM 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.

  10. Synthesis and characterization of siloxane sulfobetaine antimicrobial agents

    NASA Astrophysics Data System (ADS)

    Chen, Shiguo; Chen, Shaojun; Jiang, Song; Mo, Yangmiao; Tang, Jiaoning; Ge, Zaochuan

    In this paper, we report a novel antibacterial agent siloxane sulfobetaine (SSB) with reactive siloxane groups, which can be bonded onto the glass surface, rendering excellent antibacterial activity and good durability. Their antibacterial rate against Escherichia Coli and Staphylococcus aureus reach 99.96% and 99.98%, respectively, within the 24 h contact time. Their antibacterial rates of SSB coated glass surface are still beyond 95.0% after 20 washes. Moreover, SSB does not induce a skin reaction and is nontoxic to animals. Therefore, the SSB has great applications in biomaterial applications requiring durable bacteriostasis.

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

    PubMed

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

    2007-01-01

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

  12. Engineered Chimeric Peptides as Antimicrobial Surface Coating Agents toward Infection-Free Implants

    PubMed Central

    Yazici, Hilal; O'Neill, Mary B.; Kacar, Turgay; Wilson, Brandon R.; Oren, E. Emre; Sarikaya, Mehmet; Tamerler, Candan

    2016-01-01

    Prevention of bacterial colonization and consequent biofilm formation remains a major challenge in implantable medical devices. Implant-associated infections are not only a major cause of implant failures but also their conventional treatment with antibiotics brings further complications due to the escalation in multidrug resistance to a variety of bacterial species. Owing to their unique properties, antimicrobial peptides (AMPs) have gained significant attention as effective agents to combat colonization of microorganisms. These peptides have been shown to exhibit a wide spectrum of activities with specificity to a target cell while having a low tendency for developing bacterial resistance. Engineering biomaterial surfaces that feature AMP properties, therefore, offer a promising approach to prevent implant infections. Here, we engineered a chimeric peptide with bifunctionality that both forms a robust solid-surface coating while presenting antimicrobial property. The individual domains of the chimeric peptides were evaluated for their solid-binding kinetics to titanium substrate as well as for their antimicrobial properties in solution. The antimicrobial efficacy of the chimeric peptide on the implant material was evaluated in vitro against infection by a variety of bacteria, including Streptococcus mutans, Staphylococcus. epidermidis, and Escherichia coli, which are commonly found in oral and orthopedic implant related surgeries. Our results demonstrate significant improvement in reducing bacterial colonization onto titanium surfaces below the detectable limit. Engineered chimeric peptides with freely displayed antimicrobial domains could be a potential solution for developing infection-free surfaces by engineering implant interfaces with highly reduced bacterial colonization property. PMID:26795060

  13. Engineered Chimeric Peptides as Antimicrobial Surface Coating Agents toward Infection-Free Implants.

    PubMed

    Yazici, Hilal; O'Neill, Mary B; Kacar, Turgay; Wilson, Brandon R; Oren, E Emre; Sarikaya, Mehmet; Tamerler, Candan

    2016-03-02

    Prevention of bacterial colonization and consequent biofilm formation remains a major challenge in implantable medical devices. Implant-associated infections are not only a major cause of implant failures but also their conventional treatment with antibiotics brings further complications due to the escalation in multidrug resistance to a variety of bacterial species. Owing to their unique properties, antimicrobial peptides (AMPs) have gained significant attention as effective agents to combat colonization of microorganisms. These peptides have been shown to exhibit a wide spectrum of activities with specificity to a target cell while having a low tendency for developing bacterial resistance. Engineering biomaterial surfaces that feature AMP properties, therefore, offer a promising approach to prevent implant infections. Here, we engineered a chimeric peptide with bifunctionality that both forms a robust solid-surface coating while presenting antimicrobial property. The individual domains of the chimeric peptides were evaluated for their solid-binding kinetics to titanium substrate as well as for their antimicrobial properties in solution. The antimicrobial efficacy of the chimeric peptide on the implant material was evaluated in vitro against infection by a variety of bacteria, including Streptococcus mutans, Staphylococcus. epidermidis, and Escherichia coli, which are commonly found in oral and orthopedic implant related surgeries. Our results demonstrate significant improvement in reducing bacterial colonization onto titanium surfaces below the detectable limit. Engineered chimeric peptides with freely displayed antimicrobial domains could be a potential solution for developing infection-free surfaces by engineering implant interfaces with highly reduced bacterial colonization property.

  14. In Vivo, In Vitro, and In Silico Characterization of Peptoids as Antimicrobial Agents.

    PubMed

    Czyzewski, Ann M; Jenssen, Håvard; Fjell, Christopher D; Waldbrook, Matt; Chongsiriwatana, Nathaniel P; Yuen, Eddie; Hancock, Robert E W; Barron, Annelise E

    2016-01-01

    Bacterial resistance to conventional antibiotics is a global threat that has spurred the development of antimicrobial peptides (AMPs) and their mimetics as novel anti-infective agents. While the bioavailability of AMPs is often reduced due to protease activity, the non-natural structure of AMP mimetics renders them robust to proteolytic degradation, thus offering a distinct advantage for their clinical application. We explore the therapeutic potential of N-substituted glycines, or peptoids, as AMP mimics using a multi-faceted approach that includes in silico, in vitro, and in vivo techniques. We report a new QSAR model that we developed based on 27 diverse peptoid sequences, which accurately correlates antimicrobial peptoid structure with antimicrobial activity. We have identified a number of peptoids that have potent, broad-spectrum in vitro activity against multi-drug resistant bacterial strains. Lastly, using a murine model of invasive S. aureus infection, we demonstrate that one of the best candidate peptoids at 4 mg/kg significantly reduces with a two-log order the bacterial counts compared with saline-treated controls. Taken together, our results demonstrate the promising therapeutic potential of peptoids as antimicrobial agents.

  15. In Vivo, In Vitro, and In Silico Characterization of Peptoids as Antimicrobial Agents

    PubMed Central

    Fjell, Christopher D.; Waldbrook, Matt; Chongsiriwatana, Nathaniel P.; Yuen, Eddie; Hancock, Robert E. W.; Barron, Annelise E.

    2016-01-01

    Bacterial resistance to conventional antibiotics is a global threat that has spurred the development of antimicrobial peptides (AMPs) and their mimetics as novel anti-infective agents. While the bioavailability of AMPs is often reduced due to protease activity, the non-natural structure of AMP mimetics renders them robust to proteolytic degradation, thus offering a distinct advantage for their clinical application. We explore the therapeutic potential of N-substituted glycines, or peptoids, as AMP mimics using a multi-faceted approach that includes in silico, in vitro, and in vivo techniques. We report a new QSAR model that we developed based on 27 diverse peptoid sequences, which accurately correlates antimicrobial peptoid structure with antimicrobial activity. We have identified a number of peptoids that have potent, broad-spectrum in vitro activity against multi-drug resistant bacterial strains. Lastly, using a murine model of invasive S. aureus infection, we demonstrate that one of the best candidate peptoids at 4 mg/kg significantly reduces with a two-log order the bacterial counts compared with saline-treated controls. Taken together, our results demonstrate the promising therapeutic potential of peptoids as antimicrobial agents. PMID:26849681

  16. Lipo-γ-AApeptides as a new class of potent and broad-spectrum antimicrobial agents.

    PubMed

    Niu, Youhong; Padhee, Shruti; Wu, Haifan; Bai, Ge; Qiao, Qiao; Hu, Yaogang; Harrington, Lacey; Burda, Whittney N; Shaw, Lindsey N; Cao, Chuanhai; Cai, Jianfeng

    2012-04-26

    There is increasing demand to develop antimicrobial peptides (AMPs) as next generation antibiotic agents, as they have the potential to circumvent emerging drug resistance against conventional antibiotic treatments. Non-natural antimicrobial peptidomimetics are an ideal example of this, as they have significant potency and in vivo stability. Here we report for the first time the design of lipidated γ-AApeptides as antimicrobial agents. These lipo-γ-AApeptides show potent broad-spectrum activities against fungi and a series of Gram-positive and Gram-negative bacteria, including clinically relevant pathogens that are resistant to most antibiotics. We have analyzed their structure-function relationship and antimicrobial mechanisms using membrane depolarization and fluorescent microscopy assays. Introduction of unsaturated lipid chain significantly decreases hemolytic activity and thereby increases the selectivity. Furthermore, a representative lipo-γ-AApeptide did not induce drug resistance in S. aureus, even after 17 rounds of passaging. These results suggest that the lipo-γ-AApeptides have bactericidal mechanisms analogous to those of AMPs and have strong potential as a new class of novel antibiotic therapeutics.

  17. Metal oxide nanoparticles as antimicrobial agents: a promise for the future.

    PubMed

    Raghunath, Azhwar; Perumal, Ekambaram

    2017-02-01

    Microbial infectious diseases are a global threat to human health. Excess and improper use of antibiotics has created antimicrobial-resistant microbes that can defy clinical treatment. The hunt for safe and alternate antimicrobial agents is on in order to overcome such resistant micro-organisms, and the birth of nanotechnology offers promise to combat infectious organisms. Over the past two decades, metal oxide nanoparticles (MeO-NPs) have become an attractive alternative source to combat microbes that are highly resistant to various classes of antibiotics. Their vast array of physicochemical properties enables MeO-NPs to act as antimicrobial agents through various mechanisms. Apart from exhibiting antimicrobial properties, MeO-NPs also serve as carriers of drugs, thus barely providing a chance for micro-organisms to develop resistance. These immense multiple properties exhibited by MeO-NPs will have an impact on the treatment of deadly infectious diseases. This review discusses the mechanisms of action of MeO-NPs against micro-organisms, safety concerns, challenges and future perspectives.

  18. Susceptibilities of anaerobic bacteria isolated from animals with ovine foot rot to 28 antimicrobial agents.

    PubMed Central

    Piriz, S; Cuenca, R; Valle, J; Vadillo, S

    1992-01-01

    The agar dilution method was used to determine the inhibitory activities of 28 antimicrobial agents against 35 strains of the genus Peptostreptococcus, 4 strains of the species Peptococcus niger, 20 strains of the species Megasphaera elsdenii, 7 strains from the species Acidaminococcus fermentans, 8 strains of the genus Clostridium, 11 strains of the genus Eubacterium, and 1 strain of the species Propionibacterium acidipropionici, all of which were isolated from 125 clinical cases of ovine foot rot between January 1987 and December 1988. The three unreidopenicillins studied proved to be the most active antimicrobial agents, with a high percentage of strains being susceptible at a concentration of 64 micrograms/ml. Penicillin G, ampicillin, and the three cephalosporins studied also had good activity. Fosfomycin showed a high degree of activity among the 116 anaerobic bacteria tested. PMID:1590689

  19. Antimicrobial and anti-inflammatory activities of three chensinin-1 peptides containing mutation of glycine and histidine residues

    PubMed Central

    Dong, Weibing; Mao, Xiaoman; Guan, Yue; Kang, Yao; Shang, Dejing

    2017-01-01

    The natural peptide chensinin-1 doesnot exhibit its desired biological properties. In this study, the mutant MC1-1 was designed by replacing Gly in the chensinin-1 sequence with Trp. Mutants MC1-2 and MC1-3 were designed based on the MC1-1 sequence to investigate the specific role of His residues. The mutated peptides presented α-helicity in a membrane-mimetic environment and exhibited broad-spectrum antimicrobial activities; in contrast to Trp residues, His residues were dispensable for interacting with the cell membrane. The interactions between the mutant peptides and lipopolysaccharide (LPS) facilitated the ingestion of peptides by Gram-negative bacteria. The binding affinities of the peptides were similar, at approximately 10 μM, but ΔH for MC1-2 was −7.3 kcal.mol−1, which was 6-9 folds higher than those of MC1-1 and MC1-3, probably due to the conformational changes. All mutant peptides demonstrated the ability to inhibit LPS-induced tumour-necrosis factor-α (TNF-α) and interleukin-6 (IL-6) release from murine RAW264.7 cells. In addition, the representative peptide MC1-1showed better inhibition of serum TNF-α and IL-6 levels compared to polymyxin B (PMB), a potent binder and neutralizer of LPS as positive control in LPS-challenged mice model. These data suggest that the mutant peptides could be promising molecules for development as chensinin-based therapeutic agents against sepsis. PMID:28054660

  20. Activity of Topical Antimicrobial Agents Against Multidrug-Resistant Bacteria Recovered from Burn Patients

    DTIC Science & Technology

    2010-01-01

    both the prophylaxis and treatment of burn wound infections [18]. Agents such as silver sulfadiazine , silver nitrate, mupirocin, honey, mafenide...include emerging resistance of staphylococci to mupirocin and of Pseudomonas aeruginosa to silver sulfadiazine (Table 1) [9,18–21]. Prior studies...administered routinely peri-operatively and various topical antimicrobials are used to include silver sulfadiazine , mafe- nide acetate, silver nitrate

  1. In vitro activities of antimicrobial agents, alone and in combination, against Acinetobacter baumannii isolated from blood.

    PubMed

    Chang, S C; Chen, Y C; Luh, K T; Hsieh, W C

    1995-11-01

    In vitro activities of 15 antimicrobial agents against 90 strains of Acinetobacter baumannii isolated from blood cultures from hospitalized patients were determined using the agar dilution method. Imipenem, ofloxacin, and ciprofloxacin had the best antimicrobial activity with minimum inhibitory concentrations (MIC50s) of 0.25 mu g/ml and MIC90s of 0.5-1 mu g/ml. beta-lactam antibiotics other than imipenem had poor activity, with MIC50s ranging from 8 to 64 mu g/ml and MIC90s from 32 to > or = 256 mu g/ml. The checkerboard titration method was used to study the effects of combination of two antimicrobial agents. Combinations of ceftazidime, aztreonam, imipenem, or ciprofloxacin with amikacin showed either synergistic effects or partial synergistic effects for 40.9%-86.4% of 22 tested strains. The best in vitro activity was observed with the combination of imipenem and amikacin. No antagonistic effects were observed with the combination of imipenem and amikacin. Synergistic effects were confirmed by time-kill curve studies. In conclusion, imipenem, ofloxacin, and ciprofloxacin were the three most active agents against human blood isolates of A. baumannii. The combination of a beta-lactam or ciprofloxacin with amikacin was synergistic for some of the isolates.

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

    PubMed Central

    Gandhi, Anuradha M; Patel, Prakruti P

    2014-01-01

    Objective: To study the use of antimicrobial agents in patients on ventilator in ICU. Materials and Methods: Study was conducted at tertiary care teaching hospital Ahmedabad, India. Total 300 patients admitted in ICU and prescribed antimicrobial agents were included in the study. The data were recorded in preformed Case Record Form (CRF) and were analysed by Z and x2 Test. Results: Patients were divided into group A (patients on ventilator support) and group B (patients without ventilator support). In all the patients antimicrobial agents were prescribed empirically and more than two antimicrobial agents were prescribed in both groups. It was observed that above 60% antimicrobial agents were prescribed according to WHO, National and State Essential Medicine List (EML). Restricted antimicrobial agents (according to antimicrobial policy of tertiary care teaching hospital) were prescribed significantly (p<0.05) higher in group A as compared to group B. Resistance to antimicrobial agents by Pseudomonas aeruginosa and Kleibsella shown significantly (p<0.05) higher in group A as compared to group B. Change of antimicrobial therapy after Culture Sensitivity Test (CST) was significantly (p<0.05) higher in group A as compared to group B. Conclusion: Number of antimicrobial agents, antimicrobial resistance and change of antimicrobial therapy after CST were higher in patients on ventilator support. PMID:25584243

  3. Antimicrobial action of chelating agents: repercussions on the microorganism development, virulence and pathogenesis.

    PubMed

    Santos, A L S; Sodre, C L; Valle, R S; Silva, B A; Abi-Chacra, E A; Silva, L V; Souza-Goncalves, A L; Sangenito, L S; Goncalves, D S; Souza, L O P; Palmeira, V F; d'Avila-Levy, C M; Kneipp, L F; Kellett, A; McCann, M; Branquinha, M H

    2012-01-01

    Infections caused by resistant microorganisms often fail to respond to conventional therapy, resulting in prolonged illness, increased treatment costs and greater risk of death. Consequently, the development of novel antimicrobial drugs is becoming more demanding every day since the existing drugs either have too many side-effects or they tend to lose effectiveness due to the selection of resistant strains. In view of these facts, a number of new strategies to obstruct vital biological processes of a microbial cell have emerged; one of these is focused on the use of metal-chelating agents, which are able to selectively disturb the essential metal metabolism of the microorganism by interfering with metal acquisition and bioavailability for crucial reactions. The chelation activity is able to inhibit the biological role of metal-dependent proteins (e.g., metalloproteases and transcription factors), disturbing the microbial cell homeostasis and culminating in the blockage of microbial nutrition, growth and development, cellular differentiation, adhesion to biotic (e.g., extracellular matrix components, cell and/or tissue) and abiotic (e.g., plastic, silicone and acrylic) structures as well as controlling the in vivo infection progression. Interestingly, chelating agents also potentiate the activity of classical antimicrobial compounds. The differences between the microorganism and host in terms of the behavior displayed in the presence of chelating agents could provide exploitable targets for the development of an effective chemotherapy for these diseases. Consequently, metal chelators represent a novel group of antimicrobial agents with potential therapeutic applications. This review will focus on the anti-fungal and anti-protozoan action of the most common chelating agents, deciphering and discussing their mode of action.

  4. Risk factors for resistance to antimicrobial agents among nursing home residents.

    PubMed

    Loeb, Mark B; Craven, Sharon; McGeer, Allison J; Simor, Andrew E; Bradley, Suzanne F; Low, Donald E; Armstrong-Evans, Maxine; Moss, Lorraine A; Walter, Stephen D

    2003-01-01

    The authors prospectively collected data on exposure to antimicrobial agents and susceptibility patterns among all clinical isolates of bacteria taken from 9,156 residents of 50 nursing homes in Canada and the United States in 1998-1999. Exposure to antimicrobial agents was measured during the 10 weeks prior to detection of targeted resistant bacteria in residents and compared with antibiotic exposure during a 10-week interval in individuals with sensitive organisms. These main effects were adjusted for infection-control and staffing covariates using multiple logistic regression modeling. Increased staffing of nursing homes with registered nurses (adjusted odds ratio (OR) = 0.79 (95% confidence interval (CI): 0.72, 0.87) per registered nurse per 100 resident-days) and use of antibacterial soap (adjusted OR = 0.40, 95% CI: 0.18, 0.90) were associated with reduced risk of methicillin-resistant Staphylococcus aureus in nursing home residents. An increase in the number of hand-washing sinks per 100 residents was shown to reduce the risk of trimethoprim-sulfamethoxazole (TMP/SMX)-resistant Enterobacteriaceae (adjusted OR = 0.94, 95% CI: 0.90, 0.98). Exposure to TMP-SMX and exposure to fluoroquinolones were significant risk factors for isolation of TMP-SMX-resistant Enterobacteriaciae (adjusted OR = 1.14, 95% CI: 1.06, 1.22) and fluoroquinolone-resistant Enterobacteriaciae (adjusted OR = 1.08, 95% CI: 1.04, 1.11), respectively. These findings suggest that increased staffing, more hand-washing sinks, and use of antimicrobial soap may reduce resistance to antimicrobial agents in long-term care facilities.

  5. Synthesis and Evaluation of Ester Derivatives of 10-Hydroxycanthin-6-one as Potential Antimicrobial Agents.

    PubMed

    Zhao, Fei; Dai, Jiang-Kun; Liu, Dan; Wang, Shi-Jun; Wang, Jun-Ru

    2016-03-21

    As part of our continuing research on canthin-6-one antimicrobial agents, a new series of ester derivatives of 10-hydroxycanthin-6-one were synthesized using a simple and effective synthetic route. The structure of each compound was characterized by NMR, ESI-MS, FT-IR, UV, and elemental analysis. The antimicrobial activity of these compounds against three phytopathogenic fungi (Alternaria solani, Fusarium graminearum, and Fusarium solani) and four bacteria (Bacillus cereus, Bacillus subtilis, Ralstonia solanacearum, and Pseudomonas syringae) were evaluated using the mycelium linear growth rate method and micro-broth dilution method, respectively. The structure-activity relationship is discussed. Of the tested compounds, 4 and 7s displayed significant antifungal activity against F. graminearum, with inhibition rates of 100% at a concentration of 50 μg/mL. Compounds 5, 7s, and 7t showed the best inhibitory activity against all the tested bacteria, with minimum inhibitory concentrations (MICs) between 3.91 and 31.25 μg/mL. Thus, 7s emerged as a promising lead compound for the development of novel canthine-6-one antimicrobial agents.

  6. Structure-activity relationship study of novel iminothiadiazolo-pyrimidinone antimicrobial agents.

    PubMed

    Paudel, Atmika; Kaneko, Keiichi; Watanabe, Ayako; Matsunaga, Shigeki; Shigeki, Matsunaga; Kanai, Motomu; Motomu, Kanai; Hamamoto, Hiroshi; Sekimizu, Kazuhisa

    2013-11-01

    An iminothiadiazolo-pyrimidinone derivative, 0002-04-KK, harboring a furan moiety, acts as an antimicrobial agent with a minimum inhibitory concentration (MIC) against Staphylococcus aureus of 25 μg ml(-1). Several derivatives of 0002-04-KK were synthesized and among them 0026-59-KK, harboring a nitrofuran moiety, had the most potent antimicrobial activity with an MIC of 6 μg ml(-1). Both 0002-04-KK and 0026-59-KK inhibited the biosynthesis of DNA, RNA and proteins. Peptidoglycan biosynthesis was inhibited by 0026-59-KK, and slightly inhibited by 0002-04-KK. Derivative 0002-04-KK showed bactericidal activity in contrast to the bacteriostatic activity of 0002-04-KK. Derivative 0002-04-KK had less toxicity in silkworms (lethal dose fifty (LD50): >230 μg g(-1)) than 0002-04-KK (LD50: 100 μg g(-1)). The bactericidal activity against S. aureus was because of the nitrofuran moiety. These findings suggest that iminothiadiazolo-pyrimidinone compounds could be used as lead molecules to develop antimicrobial agents.

  7. Discovery of novel berberine imidazoles as safe antimicrobial agents by down regulating ROS generation.

    PubMed

    Wen, Si-Qi; Jeyakkumar, Ponmani; Avula, Srinivasa Rao; Zhang, Ling; Zhou, Cheng-He

    2016-06-15

    A series of novel berberine-based imidazole derivatives as new type of antimicrobial agents were developed and characterized. Most of them gave good antibacterial activity toward the Gram-positive and negative bacteria. Noticeably, imidazolyl berberine 3a exhibited low MIC value of 1μg/mL against Eberthella typhosa, which was even superior to reference drugs berberine, chloromycin and norfloxacin. The cell toxicity and ROS generation assay indicated that compound 3a showed low cell toxicity. The interactive investigation by UV-vis spectroscopic method revealed that compound 3a could effectively intercalate into calf thymus DNA to form 3a-DNA complex which might further block DNA replication to exert the powerful antimicrobial activities. The binding behavior of compound 3a to DNA topoisomerase IB revealed that hydrogen bonds and electrostatic interactions played important roles in the association of compound 3a with DNA topoisomerase IB.

  8. Pneumococcal resistance to antimicrobial agents in the province of Québec, Canada.

    PubMed Central

    Jetté, L P; Ringuette, L; Dascal, A; Lapointe, J R; Turgeon, P

    1994-01-01

    The serogroup/serotypes (SGTs) and antimicrobial susceptibilities to 10 antimicrobial agents of 110 clinical strains of Streptococcus pneumoniae were determined. Strains intermediately resistant or highly resistant to penicillin G (80 of 110) belonged predominantly to SGTs 23 (45.0%), 19 (13.7%), 6 (10.0%), 9 (6.2%), and 14 (3.7%). The MICs of all cephalosporins, tetracycline, trimethoprim-sulfamethoxazole, and chloramphenicol increased along with the MICs of penicillin G. However, erythromycin resistance and clindamycin resistance were observed more frequently among the intermediately penicillin-resistant strains. Multiple resistance was observed for 32 strains, of which 25 were highly resistant to penicillin G and belong to SGT 23F. All strains were susceptible to vancomycin. PMID:7814501

  9. Antimicrobial peptides incorporating non-natural amino acids as agents for plant protection.

    PubMed

    Ng-Choi, Iteng; Soler, Marta; Güell, Imma; Badosa, Esther; Cabrefiga, Jordi; Bardaji, Eduard; Montesinos, Emilio; Planas, Marta; Feliu, Lidia

    2014-04-01

    The control of plant pathogens is mainly based on copper compounds and antibiotics. However, the use of these compounds has some limitations. They have a high environmental impact and the use of antibiotics is not allowed in several countries. Moreover, resistance has been developed to these pathogens. The identification of new agents able to fight plant pathogenic bacteria and fungi will represent an alternative to currently used antibiotics or pesticides. Antimicrobial peptides are widely recognized as promising candidates, however naturally occurring sequences present drawbacks that limit their development. These include susceptibility to protease degradation and low bioavailability. To overcome these problems, research has focused on the introduction of unnatural amino acids into lead peptide sequences. In particular, we have improved the biological profile of antimicrobial peptides active against plant pathogenic bacteria and fungi by incorporating triazolyl, biaryl and D-amino acids into their sequence. These modifications and their influence on the biological activity are summarized.

  10. Curcumin-encapsulated nanoparticles as innovative antimicrobial and wound healing agent.

    PubMed

    Krausz, Aimee E; Adler, Brandon L; Cabral, Vitor; Navati, Mahantesh; Doerner, Jessica; Charafeddine, Rabab A; Chandra, Dinesh; Liang, Hongying; Gunther, Leslie; Clendaniel, Alicea; Harper, Stacey; Friedman, Joel M; Nosanchuk, Joshua D; Friedman, Adam J

    2015-01-01

    Burn wounds are often complicated by bacterial infection, contributing to morbidity and mortality. Agents commonly used to treat burn wound infection are limited by toxicity, incomplete microbial coverage, inadequate penetration, and rising resistance. Curcumin is a naturally derived substance with innate antimicrobial and wound healing properties. Acting by multiple mechanisms, curcumin is less likely than current antibiotics to select for resistant bacteria. Curcumin's poor aqueous solubility and rapid degradation profile hinder usage; nanoparticle encapsulation overcomes this pitfall and enables extended topical delivery of curcumin. In this study, we synthesized and characterized curcumin nanoparticles (curc-np), which inhibited in vitro growth of methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa in dose-dependent fashion, and inhibited MRSA growth and enhanced wound healing in an in vivo murine wound model. Curc-np may represent a novel topical antimicrobial and wound healing adjuvant for infected burn wounds and other cutaneous injuries.

  11. Susceptibility of various purple and green sulfur bacteria to different antimicrobial agents.

    PubMed

    Nogales, B; Guerrero, R; Esteve, I

    1994-10-15

    Several purple and green sulfur bacteria (genera Chromatium, Thiocapsa and Chlorobium) were tested for their sensitivity to different antimicrobial agents by a disc diffusion assay, using thioacetamide as a source of hydrogen sulfide for plate growth. Chlorobium limicola strains were more sensitive to amoxicillin, erythromycin and nalidixic acid, whereas gentamicin and netilmicin were more active against the purple bacteria tested. None of the organisms were sensitive to oxacillin and trimethoprim+sulfamethoxazole. The critical concentrations at the edge of the inhibition zone were also calculated for three organisms and the antimicrobials colistin, mitomycin C, penicillin G, rifampicin, and streptomycin. The results obtained suggest that colistin, mitomycin C, penicillin G would provide selective conditions against the growth of Chlorobium limicola strains, while streptomycin and other aminoglycoside antibiotics would select against purple bacteria.

  12. Top 1% of Inpatients Administered Antimicrobial Agents Comprising 50% of Expenditures: A Descriptive Study and Opportunities for Stewardship Intervention.

    PubMed

    Dela-Pena, Jennifer; Kerstenetzky, Luiza; Schulz, Lucas; Kendall, Ron; Lepak, Alexander; Fox, Barry

    2017-03-01

    OBJECTIVE To characterize the top 1% of inpatients who contributed to the 6-month antimicrobial budget in a tertiary, academic medical center and identify cost-effective intervention opportunities targeting high-cost antimicrobial utilization. DESIGN Retrospective cohort study. PATIENTS Top 1% of the antimicrobial budget from July 1 through December 31, 2014. METHODS Patients were identified through a pharmacy billing database. Baseline characteristics were collected through a retrospective medical chart review. Patients were presented to the antimicrobial stewardship team to determine appropriate utilization of high-cost antimicrobials and potential intervention opportunities. Appropriate use was defined as antimicrobial therapy that was effective, safe, and most cost-effective compared with alternative agents. RESULTS A total of 10,460 patients received antimicrobials in 6 months; 106 patients accounted for $889,543 (47.2%) of the antimicrobial budget with an antimicrobial cost per day of $219±$192 and antimicrobial cost per admission of $4,733±$7,614. Most patients were immunocompromised (75%) and were followed by the infectious disease consult service (80%). The most commonly prescribed antimicrobials for treatment were daptomycin, micafungin, liposomal amphotericin B, and meropenem. Posaconazole and valganciclovir accounted for most of the prophylactic therapy. Cost-effective opportunities (n=71) were present in 57 (54%) of 106 patients, which included dose optimization, de-escalation, dosage form conversion, and improvement in transitions of care. CONCLUSION Antimicrobial stewardship oversight is important in implementing cost-effective strategies, especially in complex and immunocompromised patients who require the use of high-cost antimicrobials. Infect Control Hosp Epidemiol 2017;38:259-265.

  13. UPLC-MS/MS determination of florfenicol and florfenicol amine antimicrobial residues in tilapia muscle.

    PubMed

    Orlando, Eduardo Adilson; Costa Roque, Aline Gabriela; Losekann, Marcos Eliseu; Colnaghi Simionato, Ana Valéria

    2016-11-01

    Despite the benefits to fish farmers, the use of antimicrobials in aquaculture has concerned consumers and competent authorities. The indiscriminate use of such substances promotes the emergence of resistant microorganisms, decreases the effectiveness of treatments, and causes possible toxic effects in humans. In Brazil, florfenicol is the only antimicrobial registered for use in aquaculture and is often used in tilapia in cage creation. Thus, this study aimed to develop a method for determination of florfenicol residues and its metabolite florfenicol amine in tilapia fillet by UPLC-MS/MS. Analytes were extracted with ethyl acetate, followed by liquid-liquid partition clean-up with hexane and SPE. The sorbents C18, phenyl and HLB-Oasis were evaluated by SPE. Phenyl sorbent showed the best results, and the extraction conditions were optimized in the sample matrix with fractional factorial design 2(4-1). The analytes were separated on a C18 chromatographic column (50×2.1mm×1.7μm) using water (A) and acetonitrile (B) as mobile phase at a flow rate of 0.3mLmin(-1) with a linear gradient (in% B): 0-2.0min: 20%; 2.0-2.5min: increase to 90%; 2.5-3.5min: 90%; 3.0-3.5min: decrease to 20%; 4.0-5.0min: 20%. The analytes were monitored in a MS/MS triple quadrupole system by MRM mode with transitions at m/z 356.1>336.1 (florfenicol) and m/z 248.1>130.1 (florfenicol amine). The optimized method was validated obtaining LOQ values of 3 and 25ngg(-1) for florfenicol and florfenicol amine, respectively, precision between 20 and 36%, absolute extraction efficiency between 38 and 80%, and adequate linearity. The method was applied to samples intended for human consumption, and within the 15 evaluated samples, only one showed florfenicol residue at 30ngg(-1), which is below the maximum residue limit established in Brazil.

  14. Coping with antibiotic resistance: combining nanoparticles with antibiotics and other antimicrobial agents.

    PubMed

    Allahverdiyev, Adil M; Kon, Kateryna Volodymyrivna; Abamor, Emrah Sefik; Bagirova, Malahat; Rafailovich, Miriam

    2011-11-01

    The worldwide escalation of bacterial resistance to conventional medical antibiotics is a serious concern for modern medicine. High prevalence of multidrug-resistant bacteria among bacteria-based infections decreases effectiveness of current treatments and causes thousands of deaths. New improvements in present methods and novel strategies are urgently needed to cope with this problem. Owing to their antibacterial activities, metallic nanoparticles represent an effective solution for overcoming bacterial resistance. However, metallic nanoparticles are toxic, which causes restrictions in their use. Recent studies have shown that combining nanoparticles with antibiotics not only reduces the toxicity of both agents towards human cells by decreasing the requirement for high dosages but also enhances their bactericidal properties. Combining antibiotics with nanoparticles also restores their ability to destroy bacteria that have acquired resistance to them. Furthermore, nanoparticles tagged with antibiotics have been shown to increase the concentration of antibiotics at the site of bacterium-antibiotic interaction, and to facilitate binding of antibiotics to bacteria. Likewise, combining nanoparticles with antimicrobial peptides and essential oils generates genuine synergy against bacterial resistance. In this article, we aim to summarize recent studies on interactions between nanoparticles and antibiotics, as well as other antibacterial agents to formulate new prospects for future studies. Based on the promising data that demonstrated the synergistic effects of antimicrobial agents with nanoparticles, we believe that this combination is a potential candidate for more research into treatments for antibiotic-resistant bacteria.

  15. In vitro synergistic effect of Psidium guineense (Swartz) in combination with antimicrobial agents against methicillin-resistant Staphylococcus aureus strains.

    PubMed

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

    2012-01-01

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

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

    PubMed Central

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

    2012-01-01

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

  17. Antibacterial and residual antimicrobial activities against Enterococcus faecalis biofilm: A comparison between EDTA, chlorhexidine, cetrimide, MTAD and QMix

    NASA Astrophysics Data System (ADS)

    Zhang, Rui; Chen, Min; Lu, Yan; Guo, Xiangjun; Qiao, Feng; Wu, Ligeng

    2015-08-01

    We compared the antibacterial and residual antimicrobial activities of five root canal irrigants (17% EDTA,2% chlorhexidine,0.2% cetrimide, MTAD, and QMix) in a model of Enterococcus faecalis biofilm formation. Sixty dentin blocks with 3-week E. faecalis biofilm were divided into six equal groups and flushed with irrigant for 2 min or left untreated. A blank control group was also established. Antibacterial activities of the irrigants were evaluated by counting colony forming units. To test residual antimicrobial activities, 280 dentin blocks were divided into seven equal groups and flushed with irrigant for 2 min or left untreated and then incubated with E. faecalis suspension for 48 h, or used as a blank. No bacteria were observed in the blank control group. The number of viable E. faecalis was significantly fewer in the irrigant-treated groups compared with the untreated control (P < 0.05). Among the five irrigants, QMix had the strongest antibacterial activity. Residual antimicrobial activities of CHX were significantly higher at 12 h, 24 h and 36 h compared to untreated control (P < 0.05). All five root canal irrigants were effective to some extent against E. faecalis, but QMix and CHX had the strongest, and CHX the longest (up to 36 h), antimicrobial activity.

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

    PubMed Central

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

    1995-01-01

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

  19. Combination effect of recombinant human interleukin-1 alpha with antimicrobial agents.

    PubMed Central

    Nakamura, S; Minami, A; Fujimoto, K; Kojima, T

    1989-01-01

    Combination effects of recombinant human interleukin-1 alpha with ceftazidime, moxalactam, gentamicin, enoxacin, amphotericin B, miconazole, or an immunoglobulin preparation were evaluated in systemic infections with Pseudomonas aeruginosa, Klebsiella pneumoniae, and Candida albicans in normal mice and systemic infection with P. aeruginosa in mice with leukopenia induced by preadministration of cyclophosphamide. Synergistic effects were generally observed at interleukin-1 alpha doses as low as 1 to 30 ng per mouse with most combinations. The results show the possibility that recombinant human interleukin-1 alpha could be of help for treating obstinate infections not successfully treated with antimicrobial agents alone. PMID:2589847

  20. Qualitative screening of veterinary anti-microbial agents in tissues, milk, and eggs of food-producing animals using liquid chromatography coupled with tandem mass spectrometry.

    PubMed

    Chen, Dongmei; Yu, Jie; Tao, Yanfei; Pan, Yuanhu; Xie, Shuyu; Huang, Lingli; Peng, Dapeng; Wang, Xu; Wang, Yulian; Liu, Zhenli; Yuan, Zonghui

    2016-04-01

    A method for the analysis of 120 drugs in animal derived food was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). These analytes belong to 12 families of veterinary anti-microbial agents (quinolones, macrolides, β-lactams, nitroimidazoles, sulfonamides, lincomycines, chloramphenicols, quinoxalines, tetracyclines, polypeptides, and antibacterial synergists) as well as other compounds not assigned to a particular drug family. The animal derived food samples include muscle and liver of swine, bovine, sheep, and chicken, as well as hen eggs and dairy milk. The sample preparation included ultrasound-assisted extraction (UAE) with acetonitrile-water and a final clean-up with auto solid-phase extraction (SPE) on HLB cartridges. The detection and quantification of 120 anti-microbial agents was performed using LC-MS/MS in positive and negative ion mode. The chromatographic separation was performed on a C18 column using acetonitrile and 0.1% formic acid as the mobile phase. The limit of detection (LOD) and limit of quantification (LOQ) of all drugs in food-producing animals were 0.5-3.0μg/kg and 1.5-10.0μg/kg, respectively. The developed method was successfully utilized to monitor real samples, which demonstrated that it is a simple, fast, and robust method, and could be used as a regulatory to screen for the presence of residues from veterinary anti-microbial drugs in animal-derived foods.

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

    PubMed

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

    2012-01-01

    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.

  2. Synthesis and biological evaluation of pyrazolylthiazole carboxylic acids as potent anti-inflammatory-antimicrobial agents.

    PubMed

    Khloya, Poonam; Kumar, Satish; Kaushik, Pawan; Surain, Parveen; Kaushik, Dhirender; Sharma, Pawan K

    2015-03-15

    Current Letter presents design, synthesis and biological evaluation of a novel series of pyrazolylthiazole carboxylates 1a-1p and corresponding acid derivatives 2a-2p. All 32 novel compounds were tested for their in vivo anti-inflammatory activity by carrageenan-induced rat paw edema method as well as for in vitro antimicrobial activity. All the tested compounds exhibited excellent AI activity profile. Three compounds 1p (R=Cl, R(1)=Cl), 2c (R=H, R(1)=F) and 2n (R=Cl, R(1)=OCH3) were identified as potent anti-inflammatory agents exhibiting edema inhibition of 93.06-89.59% which is comparable to the reference drug indomethacin (91.32%) after 3h of carrageenan injection while most of the other compounds displayed inhibition ⩾80%. In addition, pyrazolylthiazole carboxylic acids (2a-2p) also showed good antimicrobial profile. Compound 2h (R=OCH3, R(1)=Cl) showed excellent antimicrobial activity (MIC 6.25μg/mL) against both Gram positive bacteria comparable with the reference drug ciprofloxacin (MIC 6.25μg/mL).

  3. In vitro susceptibility of Helicobacter pullorum strains to different antimicrobial agents.

    PubMed

    Ceelen, Liesbeth; Decostere, Annemie; Devriese, Luc A; Ducatelle, Richard; Haesebrouck, Freddy

    2005-01-01

    The in vitro activity of 13 antimicrobial agents against 23 Helicobacter pullorum strains from poultry (21) and human (two) origin, and one human H. canadensis strain was tested by the agar dilution method. With the H. pullorum strains, monomodal distributions of Minimum Inhibitory Concentrations (MICs) were seen with lincomycin, doxycycline, gentamicin, tobramycin, erythromycin, tylosin, metronidazole, and enrofloxacin in concentration ranges considered as indicating susceptibility in other bacteria. The normal susceptibility level for nalidixic acid was situated at or slightly above the MIC breakpoints proposed for Campylobacteriaceae. Ampicillin, ceftriaxone, and sulphamethoxazole-trimethoprim showed poor activity against H. pullorum. For the H. canadensis strain, a similar susceptibility pattern was seen, except for nalidixic acid and enrofloxacin, whose MIC of >512 and 8 microg/ml, respectively, indicated resistance of this agent. With spectinomycin, a bimodal distribution of the MICs was noted for the tested strains; eight H. pullorum isolates originating from one flock showed acquired resistance (MIC>512 microg/ml).

  4. Novel Penicillin Analogues as Potential Antimicrobial Agents; Design, Synthesis and Docking Studies

    PubMed Central

    Ashraf, Zaman; Bais, Abdul; Manir, Md. Maniruzzaman; Niazi, Umar

    2015-01-01

    A number of penicillin derivatives (4a-h) were synthesized by the condensation of 6-amino penicillinic acid (6-APA) with non-steroidal anti-inflammatory drugs as antimicrobial agents. In silico docking study of these analogues was performed against Penicillin Binding Protein (PDBID 1CEF) using AutoDock Tools 1.5.6 in order to investigate the antimicrobial data on structural basis. Penicillin binding proteins function as either transpeptidases or carboxypeptidases and in few cases demonstrate transglycosylase activity in bacteria. The excellent antibacterial potential was depicted by compounds 4c and 4e against Escherichia coli, Staphylococcus epidermidus and Staphylococcus aureus compared to the standard amoxicillin. The most potent penicillin derivative 4e exhibited same activity as standard amoxicillin against S. aureus. In the enzyme inhibitory assay the compound 4e inhibited E. coli MurC with an IC50 value of 12.5 μM. The docking scores of these compounds 4c and 4e also verified their greater antibacterial potential. The results verified the importance of side chain functionalities along with the presence of central penam nucleus. The binding affinities calculated from docking results expressed in the form of binding energies ranges from -7.8 to -9.2kcal/mol. The carboxylic group of penam nucleus in all these compounds is responsible for strong binding with receptor protein with the bond length ranges from 3.4 to 4.4 Ǻ. The results of present work ratify that derivatives 4c and 4e may serve as a structural template for the design and development of potent antimicrobial agents. PMID:26267242

  5. Novel Penicillin Analogues as Potential Antimicrobial Agents; Design, Synthesis and Docking Studies.

    PubMed

    Ashraf, Zaman; Bais, Abdul; Manir, Md Maniruzzaman; Niazi, Umar

    2015-01-01

    A number of penicillin derivatives (4a-h) were synthesized by the condensation of 6-amino penicillinic acid (6-APA) with non-steroidal anti-inflammatory drugs as antimicrobial agents. In silico docking study of these analogues was performed against Penicillin Binding Protein (PDBID 1CEF) using AutoDock Tools 1.5.6 in order to investigate the antimicrobial data on structural basis. Penicillin binding proteins function as either transpeptidases or carboxypeptidases and in few cases demonstrate transglycosylase activity in bacteria. The excellent antibacterial potential was depicted by compounds 4c and 4e against Escherichia coli, Staphylococcus epidermidus and Staphylococcus aureus compared to the standard amoxicillin. The most potent penicillin derivative 4e exhibited same activity as standard amoxicillin against S. aureus. In the enzyme inhibitory assay the compound 4e inhibited E. coli MurC with an IC50 value of 12.5 μM. The docking scores of these compounds 4c and 4e also verified their greater antibacterial potential. The results verified the importance of side chain functionalities along with the presence of central penam nucleus. The binding affinities calculated from docking results expressed in the form of binding energies ranges from -7.8 to -9.2kcal/mol. The carboxylic group of penam nucleus in all these compounds is responsible for strong binding with receptor protein with the bond length ranges from 3.4 to 4.4 Ǻ. The results of present work ratify that derivatives 4c and 4e may serve as a structural template for the design and development of potent antimicrobial agents.

  6. Insights into the antimicrobial properties of hepcidins: advantages and drawbacks as potential therapeutic agents.

    PubMed

    Lombardi, Lisa; Maisetta, Giuseppantonio; Batoni, Giovanna; Tavanti, Arianna

    2015-04-10

    The increasing frequency of multi-drug resistant microorganisms has driven research into alternative therapeutic strategies. In this respect, natural antimicrobial peptides (AMPs) hold much promise as candidates for the development of novel antibiotics. However, AMPs have some intrinsic drawbacks, such as partial degradation by host proteases or inhibition by host body fluid composition, potential toxicity, and high production costs. This review focuses on the hepcidins, which are peptides produced by the human liver with a known role in iron homeostasis, as well by numerous other organisms (including fish, reptiles, other mammals), and their potential as antibacterial and antifungal agents. Interestingly, the antimicrobial properties of human hepcidins are enhanced at acidic pH, rendering these peptides appealing for the design of new drugs targeting infections that occur in body areas with acidic physiological pH. This review not only considers current research on the direct killing activity of these peptides, but evaluates the potential application of these molecules as coating agents preventing biofilm formation and critically assesses technical obstacles preventing their therapeutic application.

  7. Molecular docking and multivariate analysis of xanthones as antimicrobial and antiviral agents.

    PubMed

    Bernal, Freddy A; Coy-Barrera, Ericsson

    2015-07-21

    Xanthones are secondary metabolites which have drawn considerable interest over the last decades due to their antimicrobial properties, among others. A great number of this kind of compounds has been therefore reported, but there is a limited amount of studies on screening for biological activity. Thus, as part of our research on antimicrobial agents of natural origin, a set of 272 xanthones were submitted to molecular docking (MD) calculations with a group of seven fungal and two viral enzymes. The results indicated that prenylated xanthones are important hits for inhibition of the analyzed enzymes. The MD scores were also analyzed by multivariate statistics. Important structural details were found to be crucial for the inhibition of the tested enzymes by the xanthones. In addition, the classification of active xanthones can be achieved by statistical analysis on molecular docking scores by an affinity-antifungal activity relationship approach. The obtained results therefore are a suitable starting point for the development of antifungal and antiviral agents based on xanthones.

  8. Advantages of the Silkworm As an Animal Model for Developing Novel Antimicrobial Agents

    PubMed Central

    Panthee, Suresh; Paudel, Atmika; Hamamoto, Hiroshi; Sekimizu, Kazuhisa

    2017-01-01

    The demand for novel antibiotics to combat the global spread of multi drug-resistant pathogens continues to grow. Pathogenic bacteria and fungi that cause fatal human infections can also kill silkworms and the infected silkworms can be cured by the same antibiotics used to treat infections in the clinic. As an invertebrate model, silkworm model is characterized by its convenience, low cost, no ethical issues. The presence of conserved immune response and similar pharmacokinetics compared to mammals make silkworm infection model suitable to examine the therapeutic effectiveness of antimicrobial agents. Based on this, we utilized silkworm bacterial infection model to screen the therapeutic effectiveness of various microbial culture broths and successfully identified a therapeutically effective novel antibiotic, lysocin E, which has a novel mode of action of binding to menaquinone, thus leading to membrane damage and bactericidal activity. The similar approach to screen potential antibiotics resulted in the identification of other therapeutically effective novel antibiotics, such as nosokomycin and ASP2397 (VL-2397). In this regard, we propose that the silkworm antibiotic screening model is very effective for identifying novel antibiotics. In this review, we summarize the advantages of the silkworm model and propose that the utilization of silkworm infection model will facilitate the discovery of novel therapeutically effective antimicrobial agents. PMID:28326075

  9. Essential oils and metal ions as alternative antimicrobial agents: a focus on tea tree oil and silver.

    PubMed

    Low, Wan-Li; Kenward, Ken; Britland, Stephen T; Amin, Mohd Cim; Martin, Claire

    2017-04-01

    The increasing occurrence of hospital-acquired infections and the emerging problems posed by antibiotic-resistant microbial strains have both contributed to the escalating cost of treatment. The presence of infection at the wound site can potentially stall the healing process at the inflammatory stage, leading to the development of a chronic wound. Traditional wound treatment regimes can no longer cope with the complications posed by antibiotic-resistant strains; hence, there is a need to explore the use of alternative antimicrobial agents. Pre-antibiotic compounds, including heavy metal ions and essential oils, have been re-investigated for their potential use as effective antimicrobial agents. Essential oils have potent antimicrobial, antifungal, antiviral, anti-inflammatory, antioxidant and other beneficial therapeutic properties. Similarly, heavy metal ions have also been used as disinfecting agents because of their broad spectrum activities. Both of these alternative antimicrobials interact with many different intracellular components, thereby resulting in the disruption of vital cell functions and eventually cell death. This review will discuss the application of essential oils and heavy metal ions, particularly tea tree oil and silver ions, as alternative antimicrobial agents for the treatment of chronic, infected wounds.

  10. Residualization Rates of Near Infrared Dyes for the Rational Design of Molecular Imaging Agents

    PubMed Central

    Cilliers, Cornelius; Liao, Jianshan; Atangcho, Lydia; Thurber, Greg M.

    2016-01-01

    Purpose Near infrared (NIR) fluorescence imaging is widely used for tracking antibodies and biomolecules in vivo. Clinical and preclinical applications include intraoperative imaging, tracking therapeutics, and fluorescent labeling as a surrogate for subsequent radiolabeling. Despite their extensive use, one of the fundamental properties of NIR dyes, the residualization rate within cells following internalization, has not been systematically studied. This rate is required for the rational design of probes and proper interpretation of in vivo results. Procedures In this brief report, we measure the cellular residualization rate of eight commonly used dyes encompassing three core structures (cyanine, BODIPY, and oxazine/thiazine/carbopyronin). Results We identify residualizing (half-life > 24 hrs) and non-residualizing dyes (half-life < 24 hrs) in both the far red (~650-680 nm) and near infrared (~740-800 nm) regions. Conclusions This data will allow researchers to independently and rationally select the wavelength and residualizing nature of dyes for molecular imaging agent design. PMID:25869081

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

    PubMed

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

    2003-01-01

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

  12. Analyses comparing the antimicrobial activity and safety of current antiseptic agents: a review.

    PubMed

    Hibbard, John S

    2005-01-01

    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.

  13. Appropriateness of gram-negative agent use at a tertiary care hospital in the setting of significant antimicrobial resistance.

    PubMed

    Vora, Neil M; Kubin, Christine J; Furuya, E Yoko

    2015-01-01

    Background.  Practicing antimicrobial stewardship in the setting of widespread antimicrobial resistance among gram-negative bacilli, particularly in urban areas, is challenging. Methods.  We conducted a retrospective cross-sectional study at a tertiary care hospital with an established antimicrobial stewardship program in New York, New York to determine appropriateness of use of gram-negative antimicrobials and to identify factors associated with suboptimal antimicrobial use. Adult inpatients who received gram-negative agents on 2 dates, 1 June 2010 or 1 December 2010, were identified through pharmacy records. Clinical data were collected for each patient. Use of gram-negative agents was deemed optimal or suboptimal through chart review and according to hospital guidelines. Data were compared using χ(2) or Fischer's exact test for categorical variables and Student t test or Mann-Whitney U test for continuous variables. Results.  A total of 356 patients were included who received 422 gram-negative agents. Administration was deemed suboptimal in 26% of instances, with the most common reason being spectrum of activity too broad. In multivariable analysis, being in an intensive care unit (adjusted odds ratio [aOR], .49; 95% confidence interval [CI], .29-.84), having an infectious diseases consultation within the previous 7 days (aOR, .52; 95% CI, .28-.98), and having a history of multidrug-resistant gram-negative bacilli within the past year (aOR, .24; 95% CI, .09-.65) were associated with optimal gram-negative agent use. Beta-lactam/beta-lactamase inhibitor combination drug use (aOR, 2.6; 95% CI, 1.35-5.16) was associated with suboptimal use. Conclusions.  Gram-negative agents were used too broadly despite numerous antimicrobial stewardship program activities.

  14. Comparison of Wipe Materials and Wetting Agents for Pesticide Residue Collection from Hard Surfaces

    EPA Science Inventory

    Different wipe materials and wetting agents have been used to collect pesticide residues from surfaces, but little is known about their comparability. To inform the selection of a wipe for the National Children's Study, the analytical feasibility, collection efficiency, and preci...

  15. Chlorido-containing ruthenium(II) and iridium(III) complexes as antimicrobial agents.

    PubMed

    Pandrala, Mallesh; Li, Fangfei; Feterl, Marshall; Mulyana, Yanyan; Warner, Jeffrey M; Wallace, Lynne; Keene, F Richard; Collins, J Grant

    2013-04-07

    A series of polypyridyl-ruthenium(II) and -iridium(III) complexes that contain labile chlorido ligands, [{M(tpy)Cl}(2){μ-bb(n)}](2/4+) {Cl-Mbb(n); where M = Ru or Ir; tpy = 2,2':6',2''-terpyridine; and bb(n) = bis[4(4'-methyl-2,2'-bipyridyl)]-1,n-alkane (n = 7, 12 or 16)} have been synthesised and their potential as antimicrobial agents examined. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of the series of metal complexes against four strains of bacteria - Gram positive Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus (MRSA), and Gram negative Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) - have been determined. All the ruthenium complexes were highly active and bactericidal. In particular, the Cl-Rubb(12) complex showed excellent activity against all bacterial cell lines with MIC values of 1 μg mL(-1) against the Gram positive bacteria and 2 and 8 μg mL(-1) against E. coli and P. aeruginosa, respectively. The corresponding iridium(III) complexes also showed significant antimicrobial activity in terms of MIC values; however and surprisingly, the iridium complexes were bacteriostatic rather than bactericidal. The inert iridium(III) complex, [{Ir(phen)(2)}(2){μ-bb(12)}](6+) {where phen = 1,10-phenanthroline) exhibited no antimicrobial activity, suggesting that it could not cross the bacterial membrane. The mononuclear model complex, [Ir(tpy)(Me(2)bpy)Cl]Cl(2) (where Me(2)bpy = 4,4'-dimethyl-2,2'-bipyridine), was found to aquate very rapidly, with the pK(a) of the iridium-bound water in the corresponding aqua complex determined to be 6.0. This suggests the dinuclear complexes [Ir(tpy)Cl}(2){μ-bb(n)}](4+) aquate and deprotonate rapidly and enter the bacterial cells as 4+ charged hydroxo species.

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

    PubMed

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

    2014-11-28

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

  17. Rhamnolipids as emulsifying agents for essential oil formulations: antimicrobial effect against Candida albicans and methicillin-resistant Staphylococcus aureus.

    PubMed

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

    2014-12-10

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

  18. Soft antimicrobial agents: synthesis and activity of labile environmentally friendly long chain quaternary ammonium compounds.

    PubMed

    Thorsteinsson, Thorsteinn; Másson, Már; Kristinsson, Karl G; Hjálmarsdóttir, Martha A; Hilmarsson, Hilmar; Loftsson, Thorsteinn

    2003-09-11

    A series of soft quaternary ammonium antimicrobial agents, 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.

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

    NASA Astrophysics Data System (ADS)

    Kelly, Corey; Giuliani, Maximiliano; Dutcher, John

    2012-02-01

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

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

    PubMed Central

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

    2014-01-01

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

  1. Synthesis and biological activity of thiazolyl-acetic acid derivatives as possible antimicrobial agents.

    PubMed

    Shirai, Akihiro; Fumoto, Yasuko; Shouno, Tomoaki; Maseda, Hideaki; Omasa, Takeshi

    2013-01-01

    5a-h, a series of (5-substituted-2-methyl-1,3-thiazole-4-yl) acetic acids as heterocyclic acetic acid derivatives, was designed and synthesized from ethyl acetoacetate. The synthesized compounds were screened for their antimicrobial activities against bacterial and fungal strains, and their characteristics were investigated by assays under various temperature and pH conditions. Cytotoxicity was evaluated with the use of sheep erythrocytes and human neonate dermal fibroblasts. Similarly, agents such as lauric acid 6 and parabens 7a-b, which are used as preservative agents for commercial cosmetics and detergents, were assayed for comparison. Although the structure of 5a is simple, comprising a thiazole attached with an octyl group and acetic acid moiety, the compound showed stronger and broader antibacterial and antifungal activities among the 5 series against the tested microbes other than gram-negative bacteria. Interestingly, 5a overcame the weak antifungal activity of parabens 7a-b. Also, the cytotoxicity of 5a was less than that of parabens 7a-b, especially to human dermal fibroblasts. These results suggest that thiazolyl-acetic acid 5a is a potentially effective biocide, and that it could be used as a preservative agent in commercially sold cosmetics and detergents, facilitated by the hydrophilic and charge properties of its carboxylic acid moiety.

  2. Klebsiella species: antimicrobial susceptibilities, bactericidal kinetics, and in vitro inactivation of beta-lactam agents.

    PubMed Central

    Panwalker, A P; Trager, G M; Porembski, P E

    1980-01-01

    In vitro properties of 19 antimicrobial agents were tested with 56 isolates of Klebsiella spp. The aminoglycosides and the new beta-lactam compounds cefotaxime and moxalactam were the most inhibitory drugs tested. Chloramphenicol, tetracycline, trimethoprim, and trimethoprim-sulfamethoxazole were moderately active, whereas piperacillin, mezlocillin, and furazlocillin were ineffective against 25% of the isolates. Gentamicin was the only agent tested that was uniformly bactericidal in time-kill experiments with drug concentrations of four times the minimal inhibitory concentration. In combination studies with gentamicin, moxalactam and furazlocillin each increased the rate of bacterial killing for three of five isolates as compared with gentamicin alone, whereas chloramphenicol significantly retarded the rate of bacterial killing for the same number of strains. Furazlocillin was completely inactivated after 24 h of incubation with each of five selected strains. The inactivation of moxalactam, cefoxitin, and cephalothin was 36, 56, and 72%, respectively. In all instances in which these four agents were inactivated to levels below the minimal bactericidal concentration, there was accelerated growth after initial inhibition. However, regrowth also occurred in three instances in which drug levels were higher than the minimal bactericidal concentration. Retesting after drug exposure revealed a 4- to 32-fold rise in the minimal inhibitory concentration and minimal bactericidal concentration in two of these isolates. PMID:7235676

  3. In vitro activities of 47 antimicrobial agents against three Campylobacter spp. from pigs.

    PubMed Central

    Gebhart, C J; Ward, G E; Kurtz, H J

    1985-01-01

    The in vitro activities of 47 antimicrobial agents 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. PMID:3985597

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

    NASA Astrophysics Data System (ADS)

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

    2010-06-01

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

  5. Formation of complexes of antimicrobial agent norfloxacin with antitumor antibiotics of anthracycline series

    NASA Astrophysics Data System (ADS)

    Evstigneev, M. P.; Rybakova, K. A.; Davies, D. B.

    2007-05-01

    The formation of complexes in solutions of the norfloxacin antimicrobial agent (NOR) with daunomycin (DAU) and nogalamycin (NOG), antitumor anthracycline antibiotics, was studied using 1H NMR spectroscopy. Based on the concentration and temperature dependences of the chemical shifts of the protons of interacting molecules, the equilibrium constants and thermodynamic parameters (enthalpy and entropy) of heteroassociation of the antibiotics were calculated. It was shown that NOR interacts with DAU (NOG) in aqueous solutions forming stacked heterocomplexes with parallel orientation of the molecular chromophores. The conclusion was drawn that such interactions should be taken into account when anthracyclines and quinolones are jointly administered during combined chemotherapy, since they can contribute to the medico-biological synergistic effect of these antibiotics.

  6. Contribution of Cell Surface Hydrophobicity in the Resistance of Staphylococcus aureus against Antimicrobial Agents

    PubMed Central

    Lather, Puja; Mohanty, A. K.; Jha, Pankaj; Garsa, Anita Kumari

    2016-01-01

    Staphylococcus aureus is found in a wide variety of habitats, including human skin, where many strains are commensals that may be clinically significant or contaminants of food. To determine the physiological characteristics of resistant strain of Staphylococcus aureus against pediocin, a class IIa bacteriocin, a resistant strain was compared with wild type in order to investigate the contribution of hydrophobicity to this resistance. Additional clumping of resistant strain relative to wild type in light microscopy was considered as an elementary evidence of resistance attainment. A delay in log phase attainment was observed in resistant strain compared to the wild type strain. A significant increase in cell surface hydrophobicity was detected for resistant strain in both hexadecane and xylene indicating the contribution of cell surface hydrophobicity as adaptive reaction against antimicrobial agents. PMID:26966577

  7. In vitro susceptibilities of rapidly growing mycobacteria to newer antimicrobial agents.

    PubMed Central

    Khardori, N; Nguyen, H; Rosenbaum, B; Rolston, K; Bodey, G P

    1994-01-01

    The in vitro antimicrobial susceptibilities of 42 isolates of rapidly growing mycobacteria (Mycobacterium fortuitum, M. chelonae, and Mycobacterium species [other than M. fortuitum and M. chelonae]) to nine quinolones, including newer agents, two new aminoglycosides, and an aminocyclitol (trospectomycin) were determined by a broth microdilution method. The new quinolones, PD 117596, PD 127391, and PD 117558, showed excellent in vitro activities against M. fortuitum (MICs for 90% of isolates [MIC90s], 0.06, 0.06, and 0.12 microgram/ml, respectively). The MIC90 of ciprofloxacin for M. fortuitum was 0.5 microgram/ml. Only 14 to 28% of isolates of M. chelonae were susceptible to various quinolones. Most isolates of all three species were susceptible to the new aminoglycosides SCH 21420 and SCH 22591. The MIC90s of trospectomycin were 8 micrograms/ml for M. chelonae, 32 micrograms/ml for Mycobacterium species, and > 64 micrograms/ml for M. fortuitum. PMID:8141567

  8. Lignin model compound in alginate hydrogel: a strong antimicrobial agent with high potential in wound treatment.

    PubMed

    Spasojević, Dragica; Zmejkoski, Danica; Glamočlija, Jasmina; Nikolić, Miloš; Soković, Marina; Milošević, Verica; Jarić, Ivana; Stojanović, Marijana; Marinković, Emilija; Barisani-Asenbauer, Talin; Prodanović, Radivoje; Jovanović, Miloš; Radotić, Ksenija

    2016-12-01

    Nowadays bacterial resistance to known antibiotics is a serious health problem. In order to achieve more efficient treatment, lately there is an effort to find new substances, such as certain biomaterials, that are non-toxic to humans with antibiotic potential. Lignins and lignin-derived compounds have been proposed to be good candidates for use in medicine and health maintenance. In this study, the antibacterial activity of the lignin model polymer dehydrogenate polymer (DHP) in alginate hydrogel (Alg) was studied. The obtained results show that DHP-Alg has strong antimicrobial activity against several bacterial strains and biofilms and does not have a toxic effect on human epithelial cells. These results strongly suggest its application as a wound healing agent or as an adjunct substance for wound treatments.

  9. Bacteriostatic and bactericidal activities of 24 antimicrobial agents against Campylobacter fetus subsp. jejuni.

    PubMed

    Vanhoof, R; Gordts, B; Dierickx, R; Coignau, H; Butzler, J P

    1980-07-01

    The bacteriostatic and bactericidal activities of 24 antimicrobial agents were tested with the Dynatech MIC 2000 system against 86 strains of Campylobacter fetus subsp. jejuni from human sources. The penicillins (penicillin G, ampicillin, amoxycillin, carbenicillin) had poor activity. Ampicillin and amoxycillin were equally active. Cefotaxime revealed a rather good activity. Erythromycin, gentamicin, tobramycin, amikacin, and furazolidone were the most active compounds. Two strains (2.3%) were resistant to erythromycin. One strain (1.2%) was completely resistant to tobramycin. The tetracyclines (tetracyline, doxycycline, minocycline) were generally effective, but 8% of the strains were totally resistant to them. Minocycline was the most active. Chloramphenicol, thiamphenicol, and clindamycin had good activity. The bacteriostatic and bactericidal distributions for colistin, nalidixic acid, and metronidazole were broad.

  10. Determination of the Mutant Prevention Concentration and the Mutant Selection Window of Topical Antimicrobial Agents against Propionibacterium acnes.

    PubMed

    Nakase, Keisuke; Nakaminami, Hidemasa; Toda, Yuta; Noguchi, Norihisa

    2017-01-01

    Determination of the mutant prevention concentration (MPC) and the mutant selection window (MSW) of antimicrobial agents used to treat pathogenic bacteria is important in order to apply effective antimicrobial therapies. Here, we determined the MPCs of the major topical antimicrobial agents against Propionibacterium acnes and Staphylococcus aureus which cause skin infections and compared their MSWs. Among the MPCs of nadifloxacin and clindamycin, the clindamycin MPC was determined to be the lowest against P. acnes. In contrast, the nadifloxacin MPC was the lowest against S. aureus. Calculations based on the minimum inhibitory concentrations and MPCs showed that clindamycin has the lowest MSW against both P. acnes and S. aureus. Nadifloxacin MSWs were 4-fold higher against P. acnes than against S. aureus. It is more likely for P. acnes to acquire resistance to fluoroquinolones than S. aureus. Therefore, topical application of clindamycin contributes very little to the emergence of resistant P. acnes and S. aureus strains.

  11. In vitro model of colonization resistance by the enteric microbiota: effects of antimicrobial agents used in food-producing animals.

    PubMed

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

    2008-04-01

    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 microg/ml for some broad-spectrum antimicrobial drugs (e.g., streptomycin) to 16 microg/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.

  12. Effects of Subtherapeutic Administration of Antimicrobial Agents to Beef Cattle on the Prevalence of Antimicrobial Resistance in Campylobacter jejuni and Campylobacter hyointestinalis†

    PubMed Central

    Inglis, G. D.; McAllister, T. A.; Busz, H. W.; Yanke, L. J.; Morck, D. W.; Olson, M. E.; Read, R. R.

    2005-01-01

    The influence of antimicrobial agents 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 antimicrobial agent (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

  13. Silver-titanium dioxide nanocomposites as effective antimicrobial and antibiofilm agents

    NASA Astrophysics Data System (ADS)

    Lungu, Magdalena; Gavriliu, Ştefania; Enescu, Elena; Ion, Ioana; Brătulescu, Alexandra; Mihăescu, Grigore; Măruţescu, Luminiţa; Chifiriuc, Mariana Carmen

    2014-01-01

    Ag-TiO2 nanocomposites were successfully developed from colloidal suspensions containing 750 or 1,500 ppm silver nanoparticles (AgNPs) deposited on 5 % (w/v) titanium dioxide nanoparticles (TiO2NPs) by a chemical reduction approach. The nanocomposites were characterized by diffuse reflectance UV-Vis spectroscopy (DRS), transmission electron microscopy (TEM), scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) and dynamic light scattering (DLS). DRS spectra showed an absorption band in visible region with maximum absorbance peaks at 452 and 444 nm attributed to AgNPs plasmon peaks, indicating the formation of small spherical or quasi-spherical Ag nanocrystals in nanocomposites. TEM and SEM analysis proved a nearly spherical morphology of particles (15-30 ± 5 nm average size in diameter). EDX analysis revealed the presence of Ti, O, and Ag in both nanocomposite powders having 1.37 or 2.34 wt% Ag content. DLS analysis yielded a bimodal particle size distribution in a narrow range (31.3 ± 0.5 or 23.4 ± 0.4 nm average particle diameter) and a good polydispersity (0.247 or 0.293 polydispersity index). The nanocomposites were screened for their in vitro antimicrobial activity against Gram-positive ( Bacillus subtilis and Staphylococcus aureus) and Gram-negative ( Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa) bacterial and fungal ( Candida albicans) reference and clinical strains, in planktonic and adherent state, by qualitative and quantitative assays. The antibacterial activity increased with the increasing AgNPs content, being more intensive for Gram-positive bacteria. Both Ag-TiO2 nanocomposites exhibited a high antibiofilm activity. The obtained results recommend the use of the developed nanocomposites as antimicrobial and antibiofilm agents in practical applications without UV irradiation. The most effective agent proved to be the one with 2.34 wt% AgNPs content.

  14. Oxidation of sulfamethoxazole and related antimicrobial agents by TiO2 photocatalysis.

    PubMed

    Hu, Lanhua; Flanders, Phillip M; Miller, Penney L; Strathmann, Timothy J

    2007-06-01

    The widespread detection of pharmaceutically active compounds, including many synthetic antimicrobial agents, 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 antimicrobial agents in aqueous suspensions of nanophase titanium dioxide (TiO(2)). Experimental results demonstrate that SMX is mineralized by TiO(2) irradiated with ultraviolet-A light (UVA: 324

  15. Effects of Slime Produced by Clinical Isolates of Coagulase-Negative Staphylococci on Activities of Various Antimicrobial Agents

    PubMed Central

    Souli, Maria; Giamarellou, Helen

    1998-01-01

    A novel in vitro semiquantitative method was developed to investigate the influence of staphylococcal slime on the activities of 22 antimicrobial agents. 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. PMID:9559814

  16. The detection limits of antimicrobial agents in cow's milk by a simple Yoghurt Culture Test.

    PubMed

    Mohsenzadeh, M; Bahrainipour, A

    2008-09-15

    The aim of this study was to study performance of Yoghurt Culture Test (YCT) in the detection of antimicrobial residues in milk. For this purpose, the sensitivity of YCT for 15 antibiotics were determined. For each drug, 8 concentrations were tested. The detection limits of YCT at 2.5 h and 4 h incubation were determined (microg kg(-1)): 15 and 37.5, penicillin G; 4 and 5, ampicillin; 5 and 7.5, amoxycillin; 100 and 200, cephalexin; 80 and 100, cefazoline; 100 and 200, oxytetracycline; 500 and 100, chlortetracycline; 100 and 200, tetracycline; 150 and 200, doxycycline; 200 and 400, sulphadimidine; 500 and 1000, gentamycin; 1000 and 1500, spectinomycin; 400 and 500, erythromycin; 50 and 100, tylosin; 5000 and 10000, chloramphenicol. The YCT detection limits at 2.5 h incubation for ampicillin, cephalexin, tetracycline, oxytetracycline and tylosin are similar to those obtained as Maximum Residue Limit (MRL) according to Regulation 2377/90 EEC as set out by the European Union. In addition the detection limits of YCT for some antibiotics were lower than some of microbial inhibitor test.

  17. Efficacy of Natural and Allopathic Antimicrobial Agents Incorporated onto Guided Tissue Regeneration Membrane Against Periodontal Pathogens: An in vitro Study

    PubMed Central

    Reddy Palle, Ajay; Kumar Gedela, Rajani; Vasudevan, Sanjay

    2017-01-01

    Introduction Periodontal disease is one of the most prevalent afflictions worldwide. It is an infection of the periodontium as a result of subgingival colonization of the specific microbiota, leading to loss of attachment, which requires optimal care for regeneration to its pre-disease state. Guided Tissue Regeneration (GTR) is one of the successful treatment modalities in Periodontal Regenerative Therapy, but is vulnerable to bacterial colonization. The conflict between usage of classical antibiotics and plant origin antimicrobial agents has recently been in the limelight. Aim The aim of this study was to assess the in vitro antimicrobial activity of amoxicillin, metronidazole and green coffee extract loaded onto GTR membrane against periodonto-pathogens. Materials and Methods Pure form of amoxicillin, metronidazole and green coffee extract were obtained. One percent concentration of each antimicrobial agent was prepared by appropriate dilution with distilled water. GTR membrane was cut into a size of 1x0.5 cm under sterile conditions and was coated with the antimicrobial agents respectively and with distilled water as the negative control. Antimicrobial activity was checked against Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) and Porphyromonas gingivalis (P. gingivalis) using agar disc diffusion method. The statistical analysis was done using Kruskal Wallis ANOVA and Mann-Whitney U test. Results One percent amoxicillin showed level of significance (p>0.05) against both A. actinomycetemcomitans and P. gingivalis. Green coffee extract showed no zone of inhibition against both the bacterial species. Conclusion Loading of commercially available antimicrobial agents onto GTR membrane can prevent its bacterial colonization leading to better treatment outcomes for periodontal regeneration. PMID:28274052

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  19. Consumer-mediated nutrient recycling is influenced by interactions between nutrient enrichment and the anti-microbial agent triclosan

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Triclosan (5-chloro-2-(2, 4-dichlorophenoxy)phenol) is a widely used antimicrobial agent in personal care products whose fate and transport in aquatic ecosystems is a growing environmental concern. Evidence for chronic ecological effects of triclosan in aquatic organisms is increasing. At larger sca...

  20. Edible Coating as Carrier of Antimicrobial Agents to Extend the Shelf Life of Fresh-Cut Apples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Edible coatings with antimicrobial agents 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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  2. Influence of hydrophobic residues on the activity of the antimicrobial peptide magainin 2 and its synergy with PGLa.

    PubMed

    Strandberg, Erik; Zerweck, Jonathan; Horn, Diana; Pritz, Günther; Berditsch, Marina; Bürck, Jochen; Wadhwani, Parvesh; Ulrich, Anne S

    2015-05-01

    Magainin 2 (MAG2) and PGLa are two related antimicrobial peptides found in the skin of the African frog Xenopus laevis with a pronounced synergistic activity, which act by permeabilizing bacterial membranes. To probe the influence of hydrophobic peptide-lipid and peptide-peptide interactions on the antimicrobial activity and on synergy, the sequence of MAG2 was modified by replacing single amino acids either with a small alanine or with the stiff and bulky hydrophobic 3-(trifluoromethyl)-L-bicyclopent-[1.1.1]-1-ylglycine side chain. The minimum inhibitory concentration of 14 MAG2 analogs was strongly influenced by these single substitutions: the antimicrobial activity was consistently improved when the hydrophobicity was increased on the hydrophobic face of the amphiphilic helix, while the activity decreased when the hydrophobicity was reduced. The synergy with PGLa, on the other hand, was rather insensitive to mutations of hydrophobic residues. It thus seems that the antimicrobial effect of MAG2 on its own depends strongly on the hydrophobicity of the peptide, while the synergy with PGLa does not depend on the overall hydrophobicity of MAG2.

  3. Release time of residual oxygen after dental bleaching with 35% hydrogen peroxide: effect of a catalase-based neutralizing agent.

    PubMed

    Guasso, Bárbara; Salomone, Paloma; Nascimento, Paulo Cícero; Pozzobon, Roselaine Terezinha

    2016-01-01

    This article assessed the effect of a catalase-based agent on residual oxygen (O2) release from teeth exposed to 35% hydrogen peroxide (H2O2). The use of the catalase-based neutralizer agent for 2-3 minutes was able to release residual O2 5 days after exposure to a 35% H2O2-based bleaching gel.

  4. Distribution of drug-resistant bacteria and rational use of clinical antimicrobial agents.

    PubMed

    Zhou, Chenliang; Chen, Xiaobing; Wu, Liwen; Qu, Jing

    2016-06-01

    Open wound may lead to infection in patients. Due to overuse of medication, certain bacteria have become resistant to drugs currently available. The aim of the present study was to provide a guide to ameliorate the appropriate and rational use of clinical antimicrobial agents by analyzing the distribution of drug-resistant pathogenic bacteria in patients. Between October 2013 and January 2015, 126 patients were selected at the Department of Orthopedics. Wound secretion samples were collected, and the pathogen bacteria isolated and identified. Identification was performed using an automated identification instrument and the Kirby-Bauer antibiotic method was used to evaluate the bacterial resistance. Of the 126 patients, 118 patients were infected (infection rate, 93.65%). Additionally, 47 strains of gram-positive pathogenic bacteria (39.83%) and 71 strains of pathogenic-gram negative bacteria (60.17%) were identified. The bacteria were most likely to be resistant to penicillin while sensitive to vancomycin and imipenem. Some bacteria were resistant to several antibacterial agents. The results showed that existing risk factors at the Department of Orthopedics were complex and any non-standard procedures were able to cause bacterial infection. There were obvious dissimilarities among infectious bacteria with regard to their sensitivity to various antibacterial agents. Manipulation techniques during the treatment process were performed in a sterile manner and the use of antibacterial agents was required to be strictly in accordance with the results of drug sensitivity tests to provide effective etiologic information and a treatment plan for clinical trials and to reduce the risk of infection by multi-resistant bacteria.

  5. Effects of Pro --> peptoid residue substitution on cell selectivity and mechanism of antibacterial action of tritrpticin-amide antimicrobial peptide.

    PubMed

    Zhu, Wan Long; Lan, Hongliang; Park, Yoonkyung; Yang, Sung-Tae; Kim, Jae Il; Park, Il-Seon; You, Ho Jin; Lee, Jung Sup; Park, Yong Sun; Kim, Yangmee; Hahm, Kyung-Soo; Shin, Song Yub

    2006-10-31

    To investigate the effect of Pro --> peptoid residue substitution on cell selectivity and the mechanism of antibacterial action of Pro-containing beta-turn antimicrobial peptides, we synthesized tritrpticin-amide (TP, VRRFPWWWPFLRR-NH(2)) and its peptoid residue-substituted peptides in which two Pro residues at positions 5 and 9 are replaced with Nleu (Leu peptoid residue), Nphe (Phe peptoid residue), or Nlys (Lys peptoid residue). Peptides with Pro --> Nphe (TPf) or Pro --> Nleu substitution (TPl) retained antibacterial activity but had significantly higher toxicity to mammalian cells. In contrast, Pro --> Nlys substitution (TPk) increased the antibacterial activity but decreased the toxicity to mammalian cells. Tryptophan fluorescence studies indicated that the bacterial cell selectivity of TPk is closely correlated with a preferential interaction with negatively charged phospholipids. Interestingly, TPk was much less effective at depolarizing of the membrane potential of Staphylococus aureus and Escherichia coli spheroplasts and causing the leakage of a fluorescent dye entrapped within negatively charged vesicles. Furthermore, confocal laser-scanning microscopy showed that TPk effectively penetrated the membrane of both E. coli and S. aureus and accumulated in the cytoplasm, whereas TP and TPf did not penetrate the cell membrane but remained outside or on the cell membrane. These results suggest that the bactericidal action of TPk is due to inhibition of the intracellular components after penetration of the bacterial cell membrane. In addition, TPK with Lys substitution effectively depolarized the membrane potential of S. aureus and E. coli spheroplasts. TPK induced rapid and effective dye leakage from bacterial membrane-mimicking liposomes and did not penetrate the bacterial cell membranes. These results suggested that the ability of TPk to penetrate the bacterial cell membranes appears to involve the dual effects that are related to the increase in the

  6. Characterization of Antimicrobial Agent Loaded Eudragit RS Solvent Exchange-Induced In Situ Forming Gels for Periodontitis Treatment.

    PubMed

    Phaechamud, Thawatchai; Jantadee, Takron; Mahadlek, Jongjan; Charoensuksai, Purin; Pichayakorn, Wiwat

    2017-02-01

    Eudragit RS (ERS), a quaternary polyacrylate positively charged polymer, exhibits a very low permeability and swells in aqueous media independently of pH without dissolving. Owing to its high solubility in N-methyl pyrrolidone (NMP), it was interesting to apply as polymer matrix for solvent-exchanged in situ forming gel. The aim of this research was to prepare in situ forming gels from ERS to deliver the antimicrobial agents (doxycycline hyclate, metronidazole, and benzoyl peroxide) for periodontitis treatment. They were evaluated for viscosity and rheology, gel formation, syringeability, drug release, and antimicrobial activities. The solvent exchange between NMP and an external aqueous simulated gingival crevicular fluid stimulated the dissolved ERS transforming into the opaque rigid gel. Antimicrobial agent loaded ERS systems exhibited Newtonian flow with acceptable syringeability. The higher-loaded ERS promoted the more prolongation of drug release because of the retardation of water diffusion into the precipitated matrix. Antimicrobial activities against Staphylococcus aureus, Escherichia coli, Candida albicans, Streptococcus mutans, and Porphyromonas gingivalis depended on type of drugs and test microorganisms. Doxycycline hyclate loaded ERS systems showed these activities greater than the others; however, all of them could inhibit all test microorganisms. Thus, the solvent exchange-induced in situ forming gels comprising ERS-antimicrobial drugs exhibited potential use as localized delivery systems for periodontitis treatment.

  7. Susceptibility profiles of Nocardia spp. to antimicrobial and antituberculotic agents detected by a microplate Alamar Blue assay

    PubMed Central

    Zhao, Pan; Zhang, Xiujuan; Du, Pengcheng; Li, Guilian; Li, Luxi; Li, Zhenjun

    2017-01-01

    Nocardia species are ubiquitous in natural environments and can cause nocardiosis. Trimethoprim-sulfamethoxazole has long been the monotherapy treatment of choice, but resistance to this treatment has recently emerged. In this study, we used microplate Alamar Blue assays to determine the antimicrobial susceptibility patterns of 65 standard Nocardia isolates, including 28 type strains and 20 clinical Nocardia isolates, to 32 antimicrobial agents, including 13 little studied drugs. Susceptibility to the most commonly used drug, trimethoprim-sulfamethoxazole, was observed in 98% of the isolates. Linezolid, meropenem, and amikacin were also highly effective, with 98%, 95%, and 90% susceptibility, respectively, among the isolates. The isolates showed a high percentage of resistance or nonsusceptibility to isoniazid, rifampicin, and ethambutol. For the remaining antimicrobials, resistance was species-specific among isolates and was observed in traditional drug pattern types. In addition, the antimicrobial susceptibility profiles of a variety of rarely encountered standard Nocardia species are reported, as are the results for rarely reported clinical antibiotics. We also provide a timely update of antimicrobial susceptibility patterns that includes three new drug pattern types. The data from this study provide information on antimicrobial activity against specific Nocardia species and yield important clues for the optimization of species-specific Nocardia therapies. PMID:28252662

  8. The chemistry and applications of antimicrobial polymers: a state-of-the-art review.

    PubMed

    Kenawy, El-Refaie; Worley, S D; Broughton, Roy

    2007-05-01

    Microbial infection remains one of the most serious complications in several areas, particularly in medical devices, drugs, health care and hygienic applications, water purification systems, hospital and dental surgery equipment, textiles, food packaging, and food storage. Antimicrobials gain interest from both academic research and industry due to their potential to provide quality and safety benefits to many materials. However, low molecular weight antimicrobial agents suffer from many disadvantages, such as toxicity to the environment and short-term antimicrobial ability. To overcome problems associated with the low molecular weight antimicrobial agents, antimicrobial functional groups can be introduced into polymer molecules. The use of antimicrobial polymers offers promise for enhancing the efficacy of some existing antimicrobial agents and minimizing the environmental problems accompanying conventional antimicrobial agents by reducing the residual toxicity of the agents, increasing their efficiency and selectivity, and prolonging the lifetime of the antimicrobial agents. Research concerning the development of antimicrobial polymers represents a great a challenge for both the academic world and industry. This article reviews the state of the art of antimicrobial polymers primarily since the last comprehensive review by one of the authors in 1996. In particular, it discusses the requirements of antimicrobial polymers, factors affecting the antimicrobial activities, methods of synthesizing antimicrobial polymers, major fields of applications, and future and perspectives in the field of antimicrobial polymers.

  9. Sales of veterinary antimicrobial agents for therapeutic use in food-producing animal species in Japan between 2005 and 2010.

    PubMed

    Hosoi, Y; Asai, T; Koike, R; Tsuyuki, M; Sugiura, K

    2014-12-01

    The use of veterinary antimicrobial agents in animals can result in the emergence and selection of resistant bacteria in food-producing animals. This study elucidated the use of veterinary antimicrobial agents in Japan in terms of milligrams of active ingredient sold per kilogram of biomass between 2005 and 2010. Data on sales of antimicrobial agents and on the biomass of the target animal species were compiled from statistics published bythe Japanese Ministry of Agriculture, Forestry and Fisheries. The quantities of antimicrobials used varied between animal species: the highest usage was observed in pigs (392 to 423 mg/ kg), followed by beef cattle (45 to 67 mg/kg), broiler chickens (44 to 63 mg/kg) and dairy cattle (33 to 49 mg/kg). For the animal species combined, usage of third- and fourth-generation cefalosporins, fluoroquinolones and macrolides ranged from 0.10 to 0.14 mg/kg biomass, 1.1 to 1.3 mg/kg biomass and 7.8 to 10.6 mg/kg biomass, respectively.

  10. Gold nanoparticles synthesized by Brassica oleracea (Broccoli) acting as antimicrobial agents against human pathogenic bacteria and fungi

    NASA Astrophysics Data System (ADS)

    Piruthiviraj, Prakash; Margret, Anita; Krishnamurthy, Poornima Priyadharsani

    2016-04-01

    Production of antimicrobial agents through the synthesis of gold nanoparticles using green technology has been extensively made consistent by various researchers; yet, this study uses the flower bud's aqueous extracts of Brassica oleracea (Broccoli) as a reducing agent for chloroauric acid (1 mM). After 30 min of incubation, synthesis of gold nanoparticles (AuNps) was observed by a change in extract color from pale yellow to purple color. Synthesis of AuNps was confirmed in UV-visible spectroscopy at the range of approximately 560 nm. The SEM analysis showed the average nanoparticles size of 12-22 nm. The antimicrobial activity of AuNps was analyzed by subjecting it to human pathogenic bacteria (Gram-positive Staphylococcus aureus and Gram-negative Klebsiella pneumonia) and fungi (Aspergillus flavus, Aspergillus niger and Candida albicans) using disc diffusion method. The broccoli-synthesized AuNps showed the efficient antibacterial and antifungal activity of above-mentioned microbes. It was confirmed that AuNps have the best antimicrobial agent compared to the standard antibiotics (Gentamicin and Fluconazole). When the concentrations of AuNps were increased (10, 25, and 50 µg/ml), the sensitivity zone also increased for all the tested microbes. The synthesized AuNps are capable of rendering high antimicrobial efficacy and, hence, have a great potential in the preparation of drugs used against major bacterial and fungal diseases in humans.

  11. Synthesis of bio-based nanocomposites for controlled release of antimicrobial agents in food packaging

    NASA Astrophysics Data System (ADS)

    DeGruson, Min Liu

    The utilization of bio-based polymers as packaging materials has attracted great attention in both scientific and industrial areas due to the non-renewable and nondegradable nature of synthetic plastic packaging. Polyhydroxyalkanoate (PHA) is a biobased polymer with excellent film-forming and coating properties, but exhibits brittleness, insufficient gas barrier properties, and poor thermal stability. The overall goal of the project was to develop the polyhydroxyalkanoate-based bio-nanocomposite films modified by antimicrobial agents with improved mechanical and gas barrier properties, along with a controlled release rate of antimicrobial agents for the inhibition of foodborne pathogens and fungi in food. The ability for antimicrobial agents to intercalate into layered double hydroxides depended on the nature of the antimicrobial agents, such as size, spatial structure, and polarity, etc. Benzoate and gallate anions were successfully intercalated into LDH in the present study and different amounts of benzoate anion were loaded into LDH under different reaction conditions. Incorporation of nanoparticles showed no significant effect on mechanical properties of polyhydroxybutyrate (PHB) films, however, significantly increased the tensile strength and elongation at break of polyhydroxybutyrate-co-valerate (PHBV) films. The effects of type and concentration of LDH nanoparticles (unmodified LDH and LDH modified by sodium benzoate and sodium gallate) on structure and properties of PHBV films were then studied. The arrangement of LDH in the bio-nanocomposite matrices ranged from exfoliated to phase-separated depending on the type and concentration of LDH nanoparticles. Intercalated or partially exfoliated structures were obtained using modified LDH, however, only phase-separated structures were formed using unmodified LDH. The mechanical (tensile strength and elongation at break) and thermo-mechanical (storage modulus) properties were significantly improved with low

  12. ['In vitro' activity of different antimicrobial agents on Gram-negative nonfermentative bacilli, excluding Pseudomonas aeruginosa and Acinetobacter spp].

    PubMed

    Vay, C A; Almuzara, M N; Rodríguez, C H; Pugliese, M L; Lorenzo Barba, F; Mattera, J C; Famiglietti, A M R

    2005-01-01

    Gram-negative nonfermentative bacilli (NFB) are widely spread in the environment. Besides of difficulties for identification, they often have a marked multiresistance to antimicrobial agents, including those active against Pseudomonas aeruginosa. The objective of this study was to evaluate the 'in vitro' activity of different antimicrobial agents 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

  13. Investigation on antimicrobial agents of the terrestrial Streptomyces sp. BCC71188.

    PubMed

    Supong, Khomsan; Sripreechasak, Paranee; Tanasupawat, Somboon; Danwisetkanjana, Kannawat; Rachtawee, Pranee; Pittayakhajonwut, Pattama

    2017-01-01

    The terrestrial actinomycete strain BCC71188 was identified as Streptomyces by its morphology (having spiral chain spore on the aerial mycelium), chemotaxonomy (containing LL-diaminopimelic acid in the cell wall), and 16S rRNA gene sequence analysis [showing high similarity values compared with Streptomyces samsunensis M1463(T) (99.85 %) and Streptomyces malaysiensis NBRC 16446(T) (99.40 %)]. The crude extract exhibited antimalarial against Plasmodium falciparum (IC50 0.19 μg/ml), anti-TB against Mycobacterial tuberculosis (MIC 6.25 μg/ml), and antibacterial against Bacillus cereus (MIC 1.56 μg/ml) activities. Therefore, chemical investigation was conducted by employing bioassay-guided method and led to the isolation of 19 compounds including two cyclic peptides (1-2), five macrolides (3-7), new naphthoquinone (8), nahuoic acid C (9), geldanamycin derivatives (10-13), cyclooctatin (14), germicidins A (15) and C (16), actinoramide A (17), abierixin, and 29-O-methylabierixin. These isolated compounds were evaluated for antimicrobial activity, such as antimalarial, anti-TB, and antibacterial activities, and for cytotoxicity against both cancerous (MCF-7, KB, NCI-H187) and non-cancerous (Vero) cells. Compounds 1-7, 10-14 exhibited antimalarial (IC50 0.22-7.14 μg/ml), and elaiophylin analogs (4-6) displayed anti-TB (MIC 0.78-12.00 μg/ml) and B. cereus (MIC 0.78-3.13 μg/ml) activities. Compounds 1, 2, 14, and abierixin displayed weak cytotoxicity, indicating a potential for antimicrobial agents.

  14. Chimeric Peptides as Implant Functionalization Agents for Titanium Alloy Implants with Antimicrobial Properties

    NASA Astrophysics Data System (ADS)

    Yucesoy, Deniz T.; Hnilova, Marketa; Boone, Kyle; Arnold, Paul M.; Snead, Malcolm L.; Tamerler, Candan

    2015-04-01

    Implant-associated infections can have severe effects on the longevity of implant devices and they also represent a major cause of implant failures. Treating these infections associated with implants by antibiotics is not always an effective strategy due to poor penetration rates of antibiotics into biofilms. Additionally, emerging antibiotic resistance poses serious concerns. There is an urge to develop effective antibacterial surfaces that prevent bacterial adhesion and proliferation. A novel class of bacterial therapeutic agents, known as antimicrobial peptides (AMPs), are receiving increasing attention as an unconventional option to treat septic infection, partly due to their capacity to stimulate innate immune responses and for the difficulty of microorganisms to develop resistance towards them. While host and bacterial cells compete in determining the ultimate fate of the implant, functionalization of implant surfaces with AMPs can shift the balance and prevent implant infections. In the present study, we developed a novel chimeric peptide to functionalize the implant material surface. The chimeric peptide simultaneously presents two functionalities, with one domain binding to a titanium alloy implant surface through a titanium-binding domain while the other domain displays an antimicrobial property. This approach gains strength through control over the bio-material interfaces, a property built upon molecular recognition and self-assembly through a titanium alloy binding domain in the chimeric peptide. The efficiency of chimeric peptide both in-solution and absorbed onto titanium alloy surface was evaluated in vitro against three common human host infectious bacteria, Streptococcus mutans, Staphylococcus epidermidis, and Escherichia coli. In biological interactions such as occur on implants, it is the surface and the interface that dictate the ultimate outcome. Controlling the implant surface by creating an interface composed chimeric peptides may therefore

  15. The management of risk arising from the use of antimicrobial agents in veterinary medicine in EU/EEA countries - a review.

    PubMed

    Törneke, K; Torren-Edo, J; Grave, K; Mackay, D K J

    2015-12-01

    Antimicrobials are essential medicines for the treatment of many microbial infections in humans and animals. Only a small number of antimicrobial agents with new mechanisms of action have been authorized in recent years for use in either humans or animals. Antimicrobial resistance (AMR) arising from the use of antimicrobial agents in veterinary medicine is a concern for public health due to the detection of increasing levels of resistance in foodborne zoonotic bacteria, particularly gram-negative bacteria, and due to the detection of determinants of resistance such as Extended-spectrum beta-lactamases (ESBL) in bacteria from animals and in foodstuffs of animal origin. The importance and the extent of the emergence and spread of AMR from animals to humans has yet to be quantified. Likewise, the relative contribution that the use of antimicrobial agents in animals makes to the overall risk to human from AMR is currently a subject of debate that can only be resolved through further research. Nevertheless, risk managers have agreed that the impact on public health of the use of antimicrobials in animals should be minimized as far as possible and a variety of measures have been introduced by different authorities in the EU to achieve this objective. This article reviews a range of measures that have been implemented within European countries to reduce the occurrence and the risk of transmission of AMR to humans following the use of antimicrobial agents in animals and briefly describes some of the alternatives to the use of antimicrobial agents that are being developed.

  16. An update discussion on the current assessment of the safety of veterinary antimicrobial drug residues in food with regard to their impact on the human intestinal microbiome.

    PubMed

    Cerniglia, Carl E; Pineiro, Silvia A; Kotarski, Susan F

    2016-05-01

    The human gastrointestinal tract ecosystem consists of complex and diverse microbial communities that have now been collectively termed the intestinal microbiome. Recent scientific breakthroughs and research endeavours have increased our understanding of the important role the intestinal microbiome plays in human health and disease. The use of antimicrobial new animal drugs in food-producing animals may result in the presence of low levels of drug residues in edible foodstuffs. There is concern that antimicrobial new animal drugs in or on animal-derived food products at residue-level concentrations could disrupt the colonization barrier and/or modify the antimicrobial resistance profile of human intestinal bacteria. Therapeutic doses of antimicrobial drugs have been shown to promote shifts in the intestinal microbiome, and these disruptions promote the emergence of antimicrobial-resistant bacteria. To assess the effects of antimicrobial new animal drug residues in food on human intestinal bacteria, many national regulatory agencies and international committees follow a harmonized process, VICH GL36(R), which was issued by a trilateral organization of the European Union, the USA, and Japan called the International Cooperation on Harmonization of Technical Requirements for Veterinary Medicinal Products (VICH). The guidance describes a general approach currently used by national regulatory agencies and international committees to assess the effects of antimicrobial new animal drug residues in animal-derived food on human intestinal bacteria. The purpose of this review is to provide an overview of this current approach as part of the antimicrobial new animal drug approval process in participating countries, give insights on the microbiological endpoints used in this safety evaluation, and discuss the availability of new information. Copyright © 2016 John Wiley & Sons, Ltd.

  17. Reductive destruction and decontamination of aqueous solutions of chlorinated antimicrobial agent using bimetallic systems.

    PubMed

    Ghauch, Antoine; Tuqan, Almuthanna

    2009-05-30

    Palladium, ruthenium and silver were investigated as catalysts for the dechlorination of dichlorophen (DCP, 2,2'-methylenebis(4-chlorophenol)), an antimicrobial and anthelmintic agent largely used as algicide, fungicide and bactericide. Experiments were undertaken under oxic and anoxic conditions for experimental durations up to 180 min (3h). The anoxic conditions were achieved by purging the solutions with nitrogen gas. Reactions were performed in a 12+/-0.5 mg L(-1) DCP solution (V=20 mL) using 0.8 g of Fe(0) (40 g L(-1)). Along with micrometric Fe(0), five Fe(0)-plated systems were investigated: Pd (1%), Ru (0.01%), Ru (0.1%), Ru (1%) and Ag (1%). Metal plating was controlled by atomic absorption spectroscopy. DCP degradation was monitored using: (i) two HPLC devices, (ii) ion chromatography, (iii) UV and fluorescence spectrophotometry. Results indicated: (i) total dechlorination with Fe/Pd, (ii) partial dechlorination (40%) with Fe/Ru, and no reaction with Fe/Ag. DCP is vanished completely after 90 min of contact with Fe/Pd following a first order kinetic. The observed degradation rate k(obs) was about (3.98+/-0.10)x10(-2)min(-1), the calculated half-life t(1/2) about 17.4+/-0.9 min and a t(50) about 10.1+/-0.5 min. A DCP degradation pathway map was also proposed.

  18. In-vitro activity of 21 antimicrobial agents against Neisseria gonorrhoeae in Brussels.

    PubMed

    Gordts, B; Vanhoof, R; Hubrechts, J M; Dierickx, R; Coignau, H; Butzler, J P

    1982-02-01

    The minimum inhibitory concentrations (MIC) of 21 antimicrobial agents was measured for 80 strains of Neisseria gonorrhoeae isolated in Brussels in 1978. Bimodal distributions were found for penicillin G, ampicillin, amoxycillin, carbenicillin, and cephalexin. Of the strains, 17.5% were relatively resistant to penicillin G (MIC greater than 0.08 microgram/ml) 27.5% to ampicillin (MIC greater than 0.16 microgram/ml), 23.8% to amoxycillin, and 43.3% to carbenicillin. Cefotaxime was the most active antibiotic, with MICs in the nanogram range; 3.8% and 5% of the strains were relatively resistant to cephaloridine and cephalexin respectively, but no strains were resistant to cefazolin, cefuroxime, or cefotaxime. Resistance to tetracycline, doxycycline, minocycline, erythromycin, and spiramycin (MIC greater than 1 microgram/ml) was found in 6.3%, 2.5%, 5%, and 51.3% of the strains respectively. A very good correlation was present between chloramphenicol and thiamphenicol, with 16.3% and 10% of relatively resistant strains respectively. Only two isolates showed an MIC greater than 1.25 microgram/ml for rifampicin, and 10% of the strains needed greater than or equal to 12 microgram/ml of spectinomycin for complete inhibition of growth. A very high energy was found for the 20 : 1 combination of sulphamethoxazole and trimethoprim, with only one isolate resistant to this combination. None of the strains tested produced beta-lactamase.

  19. Comparison of methods for in vitro testing of susceptibility of porcine Mycoplasma species to antimicrobial agents.

    PubMed

    Ter Laak, E A; Pijpers, A; Noordergraaf, J H; Schoevers, E C; Verheijden, J H

    1991-02-01

    The MICs of 18 antimicrobial agents used against strains of three porcine Mycoplasma species were determined by a serial broth dilution method. Twenty field strains of M. hyorhinis, ten field strains of M. hyopneumoniae, six field strains of M. flocculare, and the type strains of these species were tested. Twelve field strains and the type strain of M. hyorhinis were also tested by an agar dilution method. Tests were read at various time points. When the broth dilution method was used, the final MIC had to be read 2 days after color changes had stopped. MICs of tetracycline, oxytetracycline, doxycycline, and minocycline were low for the three Mycoplasma species tested. MICs of chlortetracycline were 8 to 16 times higher than MICs of the other tetracyclines. Spiramycin, tylosin, kitasamycin, spectinomycin, tiamulin, lincomycin, and clindamycin were effective against all strains of M. hyorhinis and M. hyopneumoniae. The quinolones were highly effective against M. hyopneumoniae but less effective against M. hyorhinis. The susceptibility patterns for M. hyopneumoniae and M. flocculare were similar.

  20. Comparison of methods for in vitro testing of susceptibility of porcine Mycoplasma species to antimicrobial agents.

    PubMed Central

    Ter Laak, E A; Pijpers, A; Noordergraaf, J H; Schoevers, E C; Verheijden, J H

    1991-01-01

    The MICs of 18 antimicrobial agents used against strains of three porcine Mycoplasma species were determined by a serial broth dilution method. Twenty field strains of M. hyorhinis, ten field strains of M. hyopneumoniae, six field strains of M. flocculare, and the type strains of these species were tested. Twelve field strains and the type strain of M. hyorhinis were also tested by an agar dilution method. Tests were read at various time points. When the broth dilution method was used, the final MIC had to be read 2 days after color changes had stopped. MICs of tetracycline, oxytetracycline, doxycycline, and minocycline were low for the three Mycoplasma species tested. MICs of chlortetracycline were 8 to 16 times higher than MICs of the other tetracyclines. Spiramycin, tylosin, kitasamycin, spectinomycin, tiamulin, lincomycin, and clindamycin were effective against all strains of M. hyorhinis and M. hyopneumoniae. The quinolones were highly effective against M. hyopneumoniae but less effective against M. hyorhinis. The susceptibility patterns for M. hyopneumoniae and M. flocculare were similar. PMID:2024954

  1. Structural overview of toxin-antitoxin systems in infectious bacteria: a target for developing antimicrobial agents.

    PubMed

    Park, Sung Jean; Son, Woo Sung; Lee, Bong-Jin

    2013-06-01

    The bacterial toxin-antitoxin (TA) system is a module that may play a role in cell survival under stress conditions. Generally, toxin molecules act as negative regulators in cell survival and antitoxin molecules as positive regulators. Thus, the expression levels and interactions between toxins and antitoxins should be systematically harmonized so that bacteria can escape such harmful conditions. Since TA systems are able to control the fate of bacteria, they are considered potent targets for the development of new antimicrobial agents. TA systems are widely prevalent with a variety of systems existing in bacteria: there are three types of bacterial TA systems depending on the property of the antitoxin which binds either the protein toxin or mRNA coding the toxin protein. Moreover, the multiplicity of TA genes has been observed even in species of bacteria. Therefore, knowledge on TA systems such as the individual characteristics of TA systems, integrative working mechanisms of various TA systems in bacteria, interactions between toxin molecules and cellular targets, and so on is currently limited due to their complexity. In this regard, it would be helpful to know the structural characteristics of TA modules for understanding TA systems in bacteria. Until now, 85 out of the total structures deposited in PDB have been bacterial TA system proteins including TA complexes or isolated toxins/antitoxins. Here, we summarized the structural information of TA systems and analyzed the structural characteristics of known TA modules from several bacteria, especially focusing on the TA modules of several infectious bacteria.

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

    PubMed

    Ouchi, Kazunobu; Sunakawa, Keisuke

    2014-06-01

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

  3. Synthesis and biological evaluation of 2-aminobenzamide derivatives as antimicrobial agents: opening/closing pharmacophore site.

    PubMed

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

    2014-03-21

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

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

    PubMed Central

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

    2014-01-01

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

  5. Copper as an antimicrobial agent against opportunistic pathogenic and multidrug resistant Enterobacter bacteria.

    PubMed

    Tian, Wen-Xiao; Yu, Shi; Ibrahim, Muhammad; Almonaofy, Abdul Wareth; He, Liu; Hui, Qiu; Bo, Zhu; Li, Bin; Xie, Guan-Lin

    2012-08-01

    Infections by Enterobacter species are common and are multidrug resistant. The use of bactericidal surface materials such as copper has lately gained attention as an effective antimicrobial agent due to its deadly effects on bacteria, yeast, and viruses. The aim of the current study was to assess the antibacterial activity of copper surfaces against Enterobacter species. The antibacterial activity of copper surfaces was tested by overlying 5×10(6) CFU/ml suspensions of representative Enterobacter strains and comparing bacterial survival counts on copper surfaces at room temperature. Iron, stainless steel, and polyvinylchloride (PVC) were used as controls. The mechanisms responsible for bacterial killing on copper surfaces were investigated by a mutagenicity assay of the D-cycloserin (cyclA gene), single cell gel electrophoresis, a staining technique, and inductively coupled plasma mass spectroscopy. Copper yielded a significant decrease in the viable bacterial counts at 2 h exposure and a highly significant decrease at 4 h. Loss of cell integrity and a significantly higher influx of copper into bacterial cells exposed to copper surfaces, as compared to those exposed to the controls, were documented. There was no increase in mutation rate and DNA damage indicating that copper contributes to bacterial killing by adversely affecting cellular structure without directly targeting the genomic DNA. These findings suggest that copper's antibacterial activity against Enterobacter species could be utilized in health care facilities and in food processing plants to reduce the bioburden, which would increase protection for susceptible members of the community.

  6. In vivo susceptibility of the Legionnaires disease bacterium to ten antimicrobial agents.

    PubMed

    Lewis, V J; Thacker, W L; Shepard, C C; McDade, J E

    1978-03-01

    The susceptibility of the Legionnaires disease bacterium to various antimicrobial agents was determined by inoculation of embryonated eggs via the yolk sac. When administered prophylactically, the minimal dose of drug preventing all deaths due to the infection was as follows: rifampin, 0.02 mg; gentamicin, 0.25 mg; streptomycin, 0.39 mg; erythromycin, 0.62 mg; sulfadiazine, 1.56 mg; chloramphenicol, 2.50 mg; and cephalothin, 20.0 mg. Smaller amounts delayed deaths, and larger or equal amounts rendered the embryos free of infection. Oxytetracycline in the largest tested amount, 5.0 mg, protected 80% of the embryos from death, and as little as 0.31 mg delayed death. Chlortetracycline (0.50 mg) and ampicillin (10.0 mg) were ineffective. The six most effective drugs were studied in an experiment in which they were administered at various times after infection in doses that were twice the minimal prophylactic dose preventing all deaths. In this therapeutic experiment, rifampin, and erythromycin allowed 100% survival when given even 72 h after infection; gentamicin, streptomycin, sulfadiazine, and chloramphenicol did so when given 48 h after infection. All six drugs increased mean survival time when administered 72 h after infection.

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

    PubMed

    Hudson, James; Kuo, Michael; Vimalanathan, Selvarani

    2011-12-01

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

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

    PubMed Central

    Hudson, James; Kuo, Michael; Vimalanathan, Selvarani

    2011-01-01

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

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

    PubMed

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

    2014-05-01

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

  10. Activity of human beta-defensin 3 alone or combined with other antimicrobial agents against oral bacteria.

    PubMed

    Maisetta, Giuseppantonio; Batoni, Giovanna; Esin, Semih; Luperini, Filippo; Pardini, Manuela; Bottai, Daria; Florio, Walter; Giuca, Maria Rita; Gabriele, Mario; Campa, Mario

    2003-10-01

    The in vitro activities of human beta-defensin 3 (hBD-3) alone or combined with lysozyme, metronidazole, amoxicillin, and chlorhexidine were investigated with the oral bacteria Streptococcus mutans, Streptococcus sanguinis, Streptococcus sobrinus, Lactobacillus acidophilus, Actinobacillus actinomycetemcomitans, and Porphyromonas gingivalis. hBD-3 showed bactericidal activity against all of the bacterial species tested. The bactericidal effect was enhanced when the peptide was used in combination with the antimicrobial agents mentioned above.

  11. In vitro and in vivo analysis of antimicrobial agents alone and in combination against multi-drug resistant Acinetobacter baumannii

    PubMed Central

    He, Songzhe; He, Hui; Chen, Yi; Chen, Yueming; Wang, Wei; Yu, Daojun

    2015-01-01

    Objective: To investigate the in vitro and in vivo antibacterial activities of tigecycline and other 13 common antimicrobial agents, alone or in combination, against multi-drug resistant Acinetobacter baumannii. Methods: An in vitro susceptibility test of 101 A. baumannii was used to detect minimal inhibitory concentrations (MICs). A mouse lung infection model of multi-drug resistant A. baumannii, established by the ultrasonic atomization method, was used to define in vivo antimicrobial activities. Results: Multi-drug resistant A. baumannii showed high sensitivity to tigecycline (98% inhibition), polymyxin B (78.2% inhibition), and minocycline (74.2% inhibition). However, the use of these antimicrobial agents in combination with other antimicrobial agents produced synergistic or additive effects. In vivo data showed that white blood cell (WBC) counts in drug combination groups C (minocycline + amikacin) and D (minocycline + rifampicin) were significantly higher than in groups A (tigecycline) and B (polymyxin B) (P < 0.05), after administration of the drugs 24 h post-infection. Lung tissue inflammation gradually increased in the model group during the first 24 h after ultrasonic atomization infection; vasodilation, congestion with hemorrhage were observed 48 h post infection. After 3 days of anti-infective therapy in groups A, B, C, and D, lung tissue inflammation in each group gradually recovered with clear structures. The mortality rates in drug combination groups(groups C and D) were much lower than in groups A and B. Conclusion: The combination of minocycline with either rifampicin or amikacin is more effective against multi-drug resistant A. baumannii than single-agent tigecycline or polymyxin B. In addition, the mouse lung infection by ultrasonic atomization is a suitable model for drug screening and analysis of infection mechanism. PMID:26074898

  12. Composting of cow dung and crop residues using termite mounds as bulking agent.

    PubMed

    Karak, Tanmoy; Sonar, Indira; Paul, Ranjit K; Das, Sampa; Boruah, R K; Dutta, Amrit K; Das, Dilip K

    2014-10-01

    The present study reports the suitability of termite mounds as a bulking agent for composting with crop residues and cow dung in pit method. Use of 50 kg termite mound with the crop residues (stover of ground nut: 361.65 kg; soybean: 354.59 kg; potato: 357.67 kg and mustard: 373.19 kg) and cow dung (84.90 kg) formed a good quality compost within 70 days of composting having nitrogen, phosphorus and potassium as 20.19, 3.78 and 32.77 g kg(-1) respectively with a bulk density of 0.85 g cm(-3). Other physico-chemical and germination parameters of the compost were within Indian standard, which had been confirmed by the application of multivariate analysis of variance and multivariate contrast analysis. Principal component analysis was applied in order to gain insight into the characteristic variables. Four composting treatments formed two different groups when hierarchical cluster analysis was applied.

  13. Physical and Antimicrobial Properties of Starch-PVA Blend Films as Affected by the Incorporation of Natural Antimicrobial Agents

    PubMed Central

    Cano, Amalia; Cháfer, Maite; Chiralt, Amparo; González-Martínez, Chelo

    2015-01-01

    In this work, active films based on starch and PVA (S:PVA ratio of 2:1) were developed by incorporating neem (NO) and oregano essential oils (OEO). First, a screening of the antifungal effectiveness of different natural extracts (echinacea, horsetail extract, liquid smoke and neem seed oil) against two fungus (P. expansum and A. niger) was carried out. The effect of NO and OEO incorporation on the films’ physical and antimicrobial properties was analyzed. Only composite films containing OEO exhibited antibacterial and antifungal activity. Antibacterial activity occurred at low OEO concentration (6.7%), while antifungal effect required higher doses of OEO in the films. Incorporation of oils did not notably affect the water sorption capacity and water vapor barrier properties of S-PVA films, but reduced their transparency and gloss, especially at the highest concentrations. The mechanical response of the S-PVA films was also negatively affected by oil incorporation but this was only relevant at the highest oil ratio (22%). S-PVA films with 6.7% of OEO exhibited the best physical properties, without significant differences with respect to the S-PVA matrix, while exhibiting antibacterial activity. Thus, the use of OEO as a natural antimicrobial incorporated into starch-PVA films represents a good and novel alternative in food packaging applications. PMID:28231098

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

    PubMed

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

    1996-11-01

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

  15. In-vitro activity of antimicrobial agents against Neisseria gonorrhoeae in Brussels.

    PubMed

    Vanhoof, R; Vanderlinden, M P; Hubrechts, J M; Butzler, J P; Yourassowsky, E

    1978-10-01

    The minimum inhibitory concentrations (MICs) of 18 antimicrobial agents against 104 strains of Neisseria gonorrhoeae isolated in the Brussels area between January and October 1976 have been measured. The MICs for penicillin G, ampicillin, amoxycillin, carbenicillin, and cephalexin showed a bimodal distribution. The second modus strains of cephalexin (MIC = 6.25 microgram/ml) were relatively resistant to penicillin G (MIC greater than or equal to 0.08 microgram/ml). About 51% of all strains were relatively resistant to penicillin G, 40.5% to ampicillin (MIC greater than or equal to 0.16 microgram/ml), 46% to amoxycillin, and 47.5% to carbenicillin. For cephalexin and cephaloridine, 25% and 8.5% respectively of all strains were relatively resistant (MIC greater than 3.12 microgram/ml). For cefazolin all MICs fell into a range of 0.097--3.12 microgram/ml. Resistance to tetracycline, doxycycline, minocycline, erythromycin, and spiramycin (MIC greater than or equal to 1 microgram/ml) was found in 9.5%, 7%, 6%, 36.5%, and 71% respectively of all isolates. No strains were resistant to rifampicin. For chloramphenicol and thiamphenicol the MICs ranged from 0.39 to 12.5 microgram/ml and from 0.195 to 3.12 microgram/ml respectively. The results for sulphamethoxazole, trimethoprim, and the combination of sulphamethoxazole and trimethoprim in a 20:1 ratio are given and discussed. The fractional inhibitory concentration (FIC) indices have also been calculated. No beta-lactamase-producing strains were found, and a contingency coefficient C has been determined for all the pairs of antibiotics investigated.

  16. [Antimycoplasmal activities of ofloxacin and commonly used antimicrobial agents on Mycoplasma gallisepticum].

    PubMed

    Takahashi, I; Yoshida, T

    1989-05-01

    In vitro activities of ofloxacin (OFLX), a new quinolone derivative, against 29 strains of Mycoplasma gallisepticum was compared with those of 4 commonly used antimicrobial agents, doxycycline (DOXY), tylosin (TS), spectinomycin (SPCM) and thiamphenicol (TP). Antimycoplasmal activities of the drugs were evaluated on the MIC (final MIC) and MPC (minimum mycoplasmacidal concentration) values which were determined by a broth dilution procedure. The following results were obtained. 1. The MIC90s of OFLX and DOXY were both 0.20 micrograms/ml. The MICs of TS were distributed through a wide range (less than or equal to 0.006 - 0.78 micrograms/ml), and its MIC90 was 0.78 micrograms/ml. Of 29 M. gallisepticum strains, 27.6% were recognized as TS-resistant. The MIC90 values of SPCM and TP were 1.56 micrograms/ml and 3.13 micrograms/ml, respectively. The MIC90 of OFLX was equal to that of DOXY and 4- to 16-fold smaller than the values of the other 3 antibiotics. 2. The MPC of OFLX was the lowest among the antibiotics tested, its MPC90 value was 0.39 micrograms/ml and was followed by DOXY (1.56 micrograms/ml). The MPCs of TS were distributed in a wide range (0.012 - 3.13 micrograms/ml), and its MPC90 was 3.13 micrograms/ml. The MPC90 values of SPCM and TP were both 6.25 micrograms/ml. Therefore, the mycoplasmacidal activity of OFLX evaluated with MPC90 values was 4- to 16-fold greater than those of the other 4 antibiotics.

  17. Screening of commercial and pecan shell-extracted liquid smoke agents as natural antimicrobials against foodborne pathogens.

    PubMed

    Van Loo, Ellen J; Babu, D; Crandall, Philip G; Ricke, Steven C

    2012-06-01

    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.

  18. Evaluation of new antimicrobial agents on Bacillus spp. strains: docking affinity and in vitro inhibition of glutamate-racemase.

    PubMed

    Tamay-Cach, Feliciano; Correa-Basurto, José; Villa-Tanaca, Lourdes; Mancilla-Percino, Teresa; Juárez-Montiel, Margarita; Trujillo-Ferrara, José G

    2013-10-01

    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 antimicrobial agents for Bacillus spp.

  19. Multicenter laboratory evaluation of the bioMérieux Vitek antimicrobial susceptibility testing system with 11 antimicrobial agents versus members of the family Enterobacteriaceae and Pseudomonas aeruginosa.

    PubMed Central

    Doern, G V; Brueggemann, A B; Perla, R; Daly, J; Halkias, D; Jones, R N; Saubolle, M A

    1997-01-01

    A four-center study in which a total of 1,082 recent clinical isolates of members of the family Enterobacteriaceae and Pseudomonas aeruginosa were examined versus 11 antimicrobial agents with the bioMérieux Vitek susceptibility test system (Hazelwood, Mo.) and the GNS-F6 card was conducted. In addition, a challenge set consisting of the same 200 organisms was examined in each of the four participating laboratories. Results obtained with the Vitek system were compared to MICs determined by a standardized broth microdilution method. For purposes of comparison, susceptibility categories (susceptible, intermediate, or resistant) were assigned on the basis of the results of both methods. The result of the broth microdilution test was considered definitive. The total category error rate with the Vitek system and the recent clinical isolates (11,902 organism-antimicrobial comparisons) was 4.5%, i.e., 1.7% very major errors, 0.9% major errors, and 1.9% minor errors. The total category error rate calculated from tests performed with the challenge set (i.e., 8,800 organism-antimicrobial comparisons) was 5.9%, i.e., 2.2% very major errors, 1.1% major errors, and 2.6% minor errors. Very major error rates higher than the totals were noted with Enterobacter cloacae versus ampicillin-sulbactam, aztreonam, ticarcillin, and ticarcillin-clavulanate and with P. aeruginosa versus mezlocillin, ticarcillin, and ticarcillin-clavulanate. Major error rates higher than the averages were observed with Proteus mirabilis versus imipenem and with Klebsiella pneumoniae versus ofloxacin. Excellent overall interlaboratory reproducibility was observed with the Vitek system. The importance of inoculum size as a primary determinant in the accuracy of susceptibility test results with the Vitek system was clearly demonstrated in this study. Specifically, when an inoculum density fourfold higher than that recommended by the manufacturer was used, high rates of false resistance results were obtained

  20. Synthesis, Characterization and Biological Evaluation of Some Quinoxaline Derivatives: A Promising and Potent New Class of Antitumor and Antimicrobial Agents.

    PubMed

    Al-Marhabi, Aisha R; Abbas, Hebat-Allah S; Ammar, Yousry A

    2015-11-03

    In continuation of our endeavor towards the development of potent and effective anticancer and antimicrobial agents; the present work deals with the synthesis of some novel tetrazolo[1,5-a]quinoxalines, N-pyrazoloquinoxalines, the corresponding Schiff bases, 1,2,4-triazinoquinoxalines and 1,2,4-triazoloquinoxalines. These compounds were synthesized via the reaction of the key intermediate hydrazinoquinoxalines with various reagents and evaluated for anticancer and antimicrobial activity. The results indicated that tetrazolo[1,5-a]quinoxaline derivatives showed the best result, with the highest inhibitory effects towards the three tested tumor cell lines, which were higher than that of the reference doxorubicin and these compounds were non-cytotoxic to normal cells (IC50 values > 100 μg/mL). Also, most of synthesized compounds exhibited the highest degrees of inhibition against the tested strains of Gram positive and negative bacteria, so tetrazolo[1,5-a]quinoxaline derivatives show dual activity as anticancer and antimicrobial agents.

  1. Review of assessments of the human health risk associated with the use of antimicrobial agents in agriculture.

    PubMed

    Bailar, John C; Travers, Karin

    2002-06-01

    To our knowledge, no comprehensive risk assessment of agricultural uses of antimicrobial agents has been published. The published risk assessments of antimicrobial use in farm settings are all subject to multiple, serious limitations in scope, including (1) limitation to one species of microorganism; (2) limitation to one or a very few related antimicrobial agents; (3) limitation to a single outcome (death, hospital days, number of illnesses, etc.); (4) limitation to one species of farm animal (e.g., chicken or swine); and (5) limitation to therapeutic use, despite reason for concern about misstated, off-label, or illegal use. In addition, all of the risk assessments reviewed overlooked important issues by accepting 2 further limitations: (6) limiting the scope of the analysis to what has already happened and ignoring the effects of continuing the practices of recent years; and (7) examining only the effects on the species of microorganism that was initially affected and ignoring the cross-species spread of resistance by plasmid transfer. After our review of the risk assessments now available, we propose a comprehensive scheme for organizing existing knowledge and dealing with critical gaps.

  2. New Approaches to Antibiotic Use and Review of Recently Approved Antimicrobial Agents.

    PubMed

    Hahn, Andrew W; Jain, Rupali; Spach, David H

    2016-07-01

    Antimicrobial drug-resistance continues to force adaptation in our clinical practice. We explore new evidence regarding adjunctive antibiotic therapy for skin and soft tissue abscesses as well as duration of therapy for intra-abdominal abscesses. As new evidence refines optimal practice, it is essential to support clinicians in adopting practice patterns concordant with evidence-based guidelines. We review a simple approach that can 'nudge' clinicians towards concordant practices. Finally, the use of novel antimicrobials will play an increasingly important role in contemporary therapy. We review five new antimicrobials recently FDA-approved for use in drug-resistant infections: dalbavancin, oritavancin, ceftaroline, ceftolozane-tazobactam, and ceftazidime-avibactam.

  3. Microbial inhibition on hospital garments treated with Dow Corning 5700 antimicrobial agent.

    PubMed Central

    Murray, P R; Niles, A C; Heeren, R L

    1988-01-01

    We evaluated the efficacy of the antimicrobial activity of cotton-polyester fabric treated with 3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride (DC 5700), a quaternary ammonium compound bound irreversibly to the material. Significant antimicrobial activity was observed with 58 of 61 gram-positive cocci but with only 1 of 35 gram-negative bacilli and 0 of 5 yeasts. No inhibition of bacilli or yeasts was observed when the DC 5700 concentration ranged from 0.05 to 1.0% or when antimicrobial activity was assayed by the agar overlay bioassay or broth agitation methods. Images PMID:3141471

  4. Discovery of membrane active benzimidazole quinolones-based topoisomerase inhibitors as potential DNA-binding antimicrobial agents.

    PubMed

    Zhang, Ling; Addla, Dinesh; Ponmani, Jeyakkumar; Wang, Ao; Xie, Dan; Wang, Ya-Nan; Zhang, Shao-Lin; Geng, Rong-Xia; Cai, Gui-Xin; Li, Shuo; Zhou, Cheng-He

    2016-03-23

    A series of novel benzimidazole quinolones as potential antimicrobial agents were designed and synthesized. Most of the prepared compounds exhibited good or even stronger antimicrobial activities in comparison with reference drugs. The most potent compound 15m was membrane active and did not trigger the development of resistance in bacteria. It not only inhibited the formation of biofilms but also disrupted the established Staphylococcus aureus and Escherichia coli biofilms. It was able to inhibit the relaxation activity of E. coli topoisomerase IV at 10 μM concentration. Moreover, this compound also showed low toxicity against mammalian cells. Molecular modeling and experimental investigation of compound 15m with DNA suggested that this compound could effectively bind with DNA to form a steady 15m-DNA complex which might further block DNA replication to exert the powerful bioactivities.

  5. Synthesis and characterization of silver-copper core-shell nanoparticles using polyol method for antimicrobial agent

    NASA Astrophysics Data System (ADS)

    Hikmah, N.; Idrus, N. F.; Jai, J.; Hadi, A.

    2016-06-01

    Silver and copper nanoparticles are well-known as the good antimicrobial agent. The nano-size of particles influences in enhancing the antimicrobial activity. This paper discusses the effect of molarity on the microstructure and morphology of silver-copper core-shell nanoparticles prepared by a polyol method. In this study, silver-copper nanoparticles are synthesized through the green approach of polyol method using ethylene glycol (EG) as green solvent and reductant, and polyoxyethylene-(80)-sorbitan monooleate (Tween 80) as a nontoxic stabilizer. The phase and morphology of silver-copper nanoparticles are characterized by X-ray diffraction (XRD) and Field emission scanning electron microscope (FESEM) and Transmission electron microscope (TEM). The results XRD confirm the pure crystalline of silver and copper nanoparticles with face-centered cubic (FCC) structure. FESEM and TEM analysis confirm the existence of Ag and Cu nanoparticles in core-shell shape.

  6. Methylsulfonyl benzothiazoles (MSBT) derivatives: Search for new potential antimicrobial and anticancer agents.

    PubMed

    Lad, Nitin P; Manohar, Yogesh; Mascarenhas, Malcolm; Pandit, Yashwant B; Kulkarni, Mahesh R; Sharma, Rajiv; Salkar, Kavita; Suthar, Ashish; Pandit, Shivaji S

    2017-03-01

    A series of novel 4 and 5-substituted methylsulfonyl benzothiazole (MSBT) compounds having amide, alkoxy, sulfonamide, nitro and amine functionality were synthesized from sequential reactions on 5-ethoxy-2-(methylsulfonyl)benzo[d]thiazole such as nitration, reduction, sulfonation, dealkylation, etc. All synthesized compounds were screened against antimicrobial and selected screened for anticancer activity. Antimicrobial activities studies reveled that among all compounds screened, out of MSBT-07, MSBT-11, MSBT-12, MSBT-14, MSBT-19, and MSBT-27 were found to have promising antimicrobial activity at MIC range of 4-50μg/ml against selected bacterial as well as fungal species. Compounds having good antimicrobial activity were screened for cervical cancer (HeLA cell lines). Of these MSBT-07 and MSBT-12 significantly reduced the cell growth. Consequently their calculated GI50 values were found to be 0.1 or <0.1μM.

  7. [In vitro evaluation of antimicrobial activity of absorbable topical hemostatic agents used in the operating room].

    PubMed

    Piana, Andrea; Mura, Ida; Deidda, Silvia; Lo Curto, Paola; Are, Bianca Maria; Maida, Giorgio; Masia, Maria Dolores

    2013-01-01

    The aim of this study was to evaluate the antimicrobial activity of three absorbable, sterile, regenerated oxidized cellulose gauzes against ATCC and clinical isolates of bacterial and fungal strains, in particular those most frequently involved in surgical site infections. The three cellulose devices showed rapid antimicrobial activity against the microbial species tested. Their use could be a valuable adjunct to antibiotic prophylaxis in the prevention of surgical site infections.

  8. Surface Modification of Poly(amidoamine) (PAMAM) Dendrimer as Antimicrobial Agents.

    PubMed

    Charles, Shakira; Vasanthan, Nadarajah; Kwon, Dong; Sekosan, Gabriela; Ghosh, Subhas

    2012-12-05

    Poly(amidoamine) (PAMAM) (G3) dendrimer was modified into quaternary ammonium salts using tertiary amines with different chain lengths: dimethyldodecyl amine, dimethylhexyl amine, and dimethylbutyl amine using an efficient synthetic route. The antimicrobial activity of these dendrimer ammonium salts against Staphylococcus and E-coli bacteria was examined using the disc diffusion method. It was found that quaternary ammonium salt prepared with the dimethyldodecyl amine exhibits antimicrobial efficacy against Staphalococus and E.coli bacteria.

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

    PubMed

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

    2013-11-01

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

  10. Comparative in vitro activity of 16 antimicrobial agents against Actinobacillus pleuropneumoniae.

    PubMed

    Yoshimura, H; Takagi, M; Ishimura, M; Endoh, Y S

    2002-01-01

    Sixteen antimicrobial agents 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.

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

    PubMed Central

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

    2012-01-01

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

  12. Quinolone antimicrobial agents. 1. Versatile new synthesis of 1-alkyl-1,4-dihydro-4-oxo-3-quinolinecarboxylic acids.

    PubMed

    Mitscher, L A; Gracey, H E; Clark, G W; Suzuki, T

    1978-05-01

    A flexible reaction sequence has been developed which starts with readily available anthranilic acids or isatoic anhydrides and leads regiospecifically to 1-alkyl-1,4-dihydro-4-oxo-3-quinolinecarboxylic acids after reaction with 1,3-dicarbonyl compounds. The sequence is superior to earlier published methods by allowing electron-releasing and -withdrawing groups in any position on the aro;atic ring, by allowing convenient substitution at C2, and better overall yield. A number of new and known antimicrobial agents were prepared and tested in vitro, demonstrating, inter alia, that substitution of the H at C2 abolished antibacterial activity.

  13. Antimicrobial stewardship.

    PubMed

    Allerberger, F; Mittermayer, H

    2008-03-01

    The aim of antimicrobial management or stewardship programmes is to ensure proper use of antimicrobial agents in order to provide the best treatment outcomes, to lessen the risk of adverse effects (including antimicrobial resistance), and to promote cost-effectiveness. Increasingly, long-term sustainability is found to be the major focus of antimicrobial stewardship. Implementing structural measures in healthcare institutions is therefore a major, but not the sole, focus of attention in promoting prudent use of antibiotics. The problem of antimicrobial resistance requires common strategies at all levels--for the prescribers and at ward, departmental, hospital, national and international levels.

  14. Dropwort (Filipendula hexapetala Gilib.): potential role as antioxidant and antimicrobial agent

    PubMed Central

    Katanic, Jelena; Mihailovic, Vladimir; Stankovic, Nevena; Boroja, Tatjana; Mladenovic, Milan; Solujic, Slavica; Stankovic, Milan S.; Vrvic, Miroslav M.

    2015-01-01

    The aim of this study was to investigate the antioxidant activity of the methanolic extracts of Filipendula hexapetala Gilib. aerial parts (FHA) and roots (FHR) and their potential in different model systems, as well as antimicrobial activity. According to this, a number of assays were employed to evaluate the antioxidant and antimicrobial potential of F. hexapetala extracts. In addition, the antioxidant activity assays in different model systems were carried out, as well as pH, thermal and gastrointestinal stability studies. The phenolic compounds contents in FHA and FHR were also determined. The results showed that F. hexapetala extracts had considerable antioxidant activity in vitro and a great stability in different conditions. The extracts exhibited antimicrobial activity against most of the tested bacterial and fungal species. Also, the extracts contain high level of phenolic compounds, especially aerial parts extract. PMID:26417349

  15. Natural Antimicrobial/Antioxidant Agents in Meat and Poultry Products as Well as Fruits and Vegetables: A Review.

    PubMed

    Aziz, Marya; Karboune, Salwa

    2016-07-20

    Synthetic preservatives are widely used by the food industry to control the growth of spoilage and pathogenic microorganisms and to inhibit the process of lipid oxidation extending the shelf-life, quality and safety of food products. However, consumer's preference for natural food additives and concern regarding the safety of synthetic preservatives prompted the food industry to look for natural alternatives. Natural antimicrobials, including plant extracts and their essential oils, enzymes, peptides, bacteriocins, bacteriophages and fermented ingredients have all been shown to have the potential for use as alternatives to chemical antimicrobials. Some spices, herbs and other plant extracts were also reported to be strong antioxidants. The antimicrobial/antioxidant activities of some plant extracts and/or their essential oils are mainly due to the presence of some major bioactive compounds, including phenolic acids, terpenes, aldehydes and flavonoids. The proposed mechanisms of action of these natural preservatives are reported. An overview of the research done on the direct incorporation of natural preservatives agents into meat and poultry products as well as fruit and vegetables to extend their shelf-life is presented. The development of edible packaging materials containing natural preservatives is growing and their applications in selected food products are also presented in this review.

  16. ZnO and TiO2 nanoparticles as novel antimicrobial agents for oral hygiene: a review

    NASA Astrophysics Data System (ADS)

    Khan, Shams Tabrez; Al-Khedhairy, Abdulaziz A.; Musarrat, Javed

    2015-06-01

    Oral cavity is inhabited by more than 25,000 different bacterial phylotypes; some of them cause systemic infections in addition to dental and periodontal diseases. Emergence of multiple antibiotic resistance among these bacteria necessitates the development of alternative antimicrobial agents that are safe, stable, and relatively economic. This review focuses on the significance of metal oxide nanoparticles, especially zinc oxide and titanium dioxide nanoparticles as supplementary antimicrobials for controlling oral infections and biofilm formation. Indeed, the ZnO NPs and TiO2 NPs have exhibited significant antimicrobial activity against oral bacteria at concentrations which is not toxic in in vivo toxicity assays. These nanoparticles are being produced at an industrial scale for use in a variety of commercial products including food products. Thus, the application of ZnO and TiO2 NPs as nanoantibiotics for the development of mouthwashes, dental pastes, and other oral hygiene materials is envisaged. It is also suggested that these NPs could serve as healthier, innocuous, and effective alternative for controlling both the dental biofilms and oral planktonic bacteria with lesser side effects and antibiotic resistance.

  17. Zinc Oxide Nanorods-Decorated Graphene Nanoplatelets: A Promising Antimicrobial Agent against the Cariogenic Bacterium Streptococcus mutans

    PubMed Central

    Zanni, Elena; Chandraiahgari, Chandrakanth Reddy; De Bellis, Giovanni; Montereali, Maria Rita; Armiento, Giovanna; Ballirano, Paolo; Polimeni, Antonella; Sarto, Maria Sabrina; Uccelletti, Daniela

    2016-01-01

    Nanomaterials are revolutionizing the field of medicine to improve the quality of life due to the myriad of applications stemming from their unique properties, including the antimicrobial activity against pathogens. In this study, the antimicrobial and antibiofilm properties of a novel nanomaterial composed by zinc oxide nanorods-decorated graphene nanoplatelets (ZNGs) are investigated. ZNGs were produced by hydrothermal method and characterized through field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) techniques. The antimicrobial activity of ZNGs was evaluated against Streptococcus mutans, the main bacteriological agent in the etiology of dental caries. Cell viability assay demonstrated that ZNGs exerted a strikingly high killing effect on S. mutans cells in a dose-dependent manner. Moreover, FE-SEM analysis revealed relevant mechanical damages exerted by ZNGs at the cell surface of this dental pathogen rather than reactive oxygen species (ROS) generation. In addition, inductively coupled plasma mass spectrometry (ICP-MS) measurements showed negligible zinc dissolution, demonstrating that zinc ion release in the suspension is not associated with the high cell mortality rate. Finally, our data indicated that also S. mutans biofilm formation was affected by the presence of graphene-zinc oxide (ZnO) based material, as witnessed by the safranin staining and growth curve analysis. Therefore, ZNGs can be a remarkable nanobactericide against one of the main dental pathogens. The potential applications in dental care and therapy are very promising. PMID:28335307

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

    PubMed Central

    Gribble, M J

    1994-01-01

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

  19. Novel 4-Thiazolidinone Derivatives as Anti-Infective Agents: Synthesis, Characterization, and Antimicrobial Evaluation.

    PubMed

    Gupta, Amit; Singh, Rajendra; Sonar, Pankaj K; Saraf, Shailendra K

    2016-01-01

    A series of new 4-thiazolidinone derivatives was synthesized, characterized by spectral techniques, and screened for antimicrobial activity. All the compounds were evaluated against five Gram-positive bacteria, two Gram-negative bacteria, and two fungi, at concentrations of 50, 100, 200, 400, 800, and 1600 µg/mL, respectively. Minimum inhibitory concentrations of all the compounds were also determined and were found to be in the range of 100-400 µg/mL. All the compounds showed moderate-to-good antimicrobial activity. Compounds 4a [2-(4-fluoro-phenyl)-3-(4-methyl-5,6,7,8-tetrahydro-quinazolin-2-yl)-thiazolidin-4-one] and 4e [3-(4,6-dimethyl-pyrimidin-2-yl)-2-(2-methoxy-phenyl)-thiazolidin-4-one] were the most potent compounds of the series, exhibiting marked antimicrobial activity against Pseudomonas fluorescens, Staphylococcus aureus, and the fungal strains. Thus, on the basis of results obtained, it may be concluded that synthesized compounds exhibit a broad spectrum of antimicrobial activity.

  20. Membrane-active Antimicrobial Peptides as Template Structures for Novel Antibiotic Agents.

    PubMed

    Lohner, Karl

    2017-01-01

    The increase of pathogens being resistant to antibiotics represents a global health problem and therefore it is a pressing need to develop antibiotics with novel mechanisms of action. Host defense peptides, which have direct antimicrobial activity (also termed antimicrobial peptides) or immune modulating activity, are valuable template structures for the development of such compounds. Antimicrobial peptides exhibit remarkably different structures as well as biological activity profiles with multiple targets. A large fraction of these peptides interfere physically with the cell membrane of bacteria (focus of this review), but can also translocate into the cytosol, where they interact with nucleic acids, ribosomes and proteins. Several potential interaction sites have to be considered on the route of the peptides from the environment to the cytoplasmic membrane. Translocation of peptides through the cell wall may not be impaired by the thick but relatively porous peptidoglycan layer. However, interaction with lipopolysaccharides of the outer membrane of Gram-negative bacteria and (lipo)teichoic acids of Gram-positive bacteria may reduce the effective concentration at the cytoplasmic membrane, where supposedly the killing event takes place. On a molecular level several mechanisms are discussed, which are important for the rational design of improved antimicrobial compounds: toroidal pore formation, carpet model (coverage of membrane surface by peptides), interfacial activity, void formation, clustering of lipids and effects of membrane curvature. In summary, many of these models just represent special cases that can be interrelated to each other and depend on both the nature of lipids and peptides.

  1. Chitin nanofibers as reinforcing and antimicrobial agents in carboxymethyl cellulose films: Influence of partial deacetylation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of edible, environmentally friendly, mechanically strong and antimicrobial biopolymer films for active food packaging has gained considerable interest in recent years. The present work deals with the extraction and deacetylation of chitin nanofibers (ChNFs) from crab shells and their...

  2. Physicochemical investigations of biogenic chitosan-silver nanocomposite as antimicrobial and anticancer agent.

    PubMed

    Arjunan, Nithya; Kumari, Henry Linda Jeeva; Singaravelu, Chandra Mohan; Kandasamy, Ruckmani; Kandasamy, Jothivenkatachalam

    2016-11-01

    Chitosan (CS), a seaweed polysaccharide is a natural macromolecule which is widely being used in medical applications because of its distinctive antimicrobial and anticancer properties. Silver, a noble metal, is also receiving wide attention for its potential usage in antimicrobial and anticancer therapeutics. In this study, an effective way of reduction of silver using chitosan at varying reaction temperatures and an optimised concentration of silver were performed. The optical, structural, spectral, morphological and elemental studies of the biosynthesized chitosan-silver (CS-Ag) nanocomposites were characterized by several techniques. The synthesized CS-Ag nanocomposites exhibit particle size around 20nm and were further exploited for potent biological applications in nanomedicine due to their nanometric sizes and biocompatibility of chitosan. The antimicrobial activity of the biosynthesized CS-Ag nanocomposites exhibits zone of inhibition ranged between 09.666±0.577 and 19.000±1.000 (mm). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were from 8 to 128μgmL(-1) and 16 to 256μgmL(-1) respectively, with the highest antimicrobial activity shown against Gram-negative Salmonella sp. The synergistic effect of chitosan and silver as a composite in nanometric size revealed significant IC50 value of 29.35μgmL(-1) and a maximum of 95.56% inhibition at 100μgmL(-1) against A549 lung cancer cell line, resulting in potent anticancer effect.

  3. In vitro activities of antimicrobial agents against Proteus species from clinical specimens.

    PubMed

    Na'was, T E; Mawajdeh, S; Dababneh, A; al-Omari, A

    1994-06-01

    Two hundred clinical isolates of members of the genus Proteus were definitively identified and their antimicrobial susceptibilities to 12 antimicrobials tested, 176 isolates (88%) being identified as Proteus mirabilis, 12 strains (6%) as Proteus vulgaris and 12 strains (6%) as Proteus penneri. Most strains were isolated from pus (62.5%) and urine (34%), but in general there were no significant differences in the rates of isolation of any of the species by age or sex, although it was noted that P. vulgaris was only isolated from patients belonging to the older age group (> 5 years). The Proteus spp. were notably susceptible to nalidixic acid, ceftazidime and the aminoglycosides tested, and resistant to polymyxin B and colistin. The inclination of certain Proteus species to be susceptible or resistant to certain antimicrobials was noted, but strain differences also existed. The results of the study confirm the importance of performing antimicrobials susceptibility testing of each Proteus isolate to avoid potentially misleading therapy. The noted discrepancy in the result of the susceptibility of P. penneri to chloramphenicol as tested by different standard methods merits further investigation.

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

    PubMed

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

    2015-01-01

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

  5. In vitro activity of five tetracyclines and some other antimicrobial agents against four porcine respiratory tract pathogens.

    PubMed

    Pijpers, A; Van Klingeren, B; Schoevers, E J; Verheijden, J H; Van Miert, A S

    1989-09-01

    The minimal inhibitory concentrations (MIC) of five tetracyclines and ten other antimicrobial agents were determined for four porcine bacterial respiratory tract pathogens by the agar dilution method. For the following oxytetracycline-susceptible strains, the MIC50 ranges of the tetracyclines were: P. multocida (n = 17) 0.25-0.5 micrograms/ml; B. bronchiseptica (n = 20) 0.25-1.0 micrograms/ml; H. pleuropneumoniae (n = 20) 0.25-0.5 micrograms/ml; S. suis Type 2 (n = 20) 0.06-0.25 micrograms/ml. For 19 oxytetracycline-resistant P. multocida strains the MIC50 of the tetracyclines varied from 64 micrograms/ml for oxytetracycline to 0.5 micrograms/ml for minocycline. Strikingly, minocycline showed no cross-resistance with oxytetracycline, tetracycline, chlortetracycline and doxycycline in P. multocida and in H. pleuropneumoniae. Moreover, in susceptible strains minocycline showed the highest in vitro activity followed by doxycycline. Low MIC50 values were observed for chloramphenicol, ampicillin, flumequine, ofloxacin and ciprofloxacin against P. multocida and H. pleuropneumoniae. B. bronchiseptica was moderately susceptible or resistant to these compounds. As expected tiamulin, lincomycin, tylosin and spiramycin were not active against H. pleuropneumoniae. Except for flumequine, the MIC50 values of nine antimicrobial agents were low for S. suis Type 2. Six strains of this species showed resistance to the macrolides and lincomycin.

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

    PubMed Central

    2010-01-01

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

  7. High CO2 concentration as an inductor agent to drive production of recombinant phytotoxic antimicrobial peptides in plant biofactories.

    PubMed

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

    2016-03-01

    Cationic α-helical antimicrobial peptides such as BP100 are of increasing interest for developing novel phytosanitary or therapeutic agents and products with industrial applications. Biotechnological production of these peptides in plants can be severely impaired due to the toxicity exerted on the host by high-level expression. This can be overcome by using inducible promoters with extremely low activity throughout plant development, although the yields are limited. We examined the use of modified atmospheres using the increased levels of [CO2], commonly used in the food industry, as the inductor agent to biotechnologically produce phytotoxic compounds with higher yields. Here we show that 30% [CO2] triggered a profound transcriptional response in rice leaves, including a change in the energy provision from photosynthesis to glycolysis, and the activation of stress defense mechanisms. Five genes with central roles in up-regulated pathways were initially selected and their promoters successfully used to drive the expression of phytotoxic BP100 in genetically modified (GM) rice. GM plants had a normal phenotype on development and seed production in non-induction conditions. Treatment with 30 % [CO2] led to recombinant peptide accumulation of up to 1 % total soluble protein when the Os.hb2 promoter was used. This is within the range of biotechnological production of other peptides in plants. Using BP100 as a proof-of-concept we demonstrate that very high [CO2] can be considered an economically viable strategy to drive production of recombinant phytotoxic antimicrobial peptides in plant biofactories.

  8. Antimicrobial Activity.

    PubMed

    2016-01-01

    Natural products of higher plants may possess a new source of antimicrobial agents with possibly novel mechanisms of action. They are effective in the treatment of infectious diseases while simultaneously mitigating many of the side effects that are often associated with conventional antimicrobials. A method using scanning electron microscope (SEM) to study the morphology of the bacterial and fungal microbes and thus determining antimicrobial activity is presented in the chapter.

  9. Role of Phenylalanine and Valine10 Residues in the Antimicrobial Activity and Cytotoxicity of Piscidin-1

    PubMed Central

    Lee, Eunjung; Shin, Areum; Jeong, Ki-Woong; Jin, Bongwhan; Jnawali, Hum Nath; Shin, Soyoung; Shin, Song Yub; Kim, Yangmee

    2014-01-01

    Piscidin-1 (Pis-1) is a linear antibacterial peptide derived from mast cells of aquacultured hybrid striped bass that comprises 22 amino acids with a phenylalanine-rich amino-terminus. Pis-1 exhibits potent antibacterial activity against pathogens but is not selective for distinguishing between bacterial and mammalian cells. To determine the key residues for its antibacterial activity and those for its cytotoxicity, we investigated the role of each Phe residue near the N-terminus as well as the Val10 residue located near the boundary of the hydrophobic and hydrophilic sectors of the helical wheel diagram. Fluorescence dye leakage and tryptophan fluorescence experiments were used to study peptide-lipid interactions, showing comparable depths of insertion of substituted peptides in different membranes. Phe2 was found to be the most deeply inserted phenylalanine in both bacterial- and mammalian-mimic membranes. Each Phe was substituted with Ala or Lys to investigate its functional role. Phe2 plays key roles in the cytotoxicity as well as the antibacterial activities of Pis-1, and Phe6 is essential for the antibacterial activities of Pis-1. We also designed and synthesized a piscidin analog, Pis-V10K, in which Lys was substituted for Val10, resulting in an elevated amphipathic α-helical structure. Pis-V10K showed similar antibacterial activity (average minimum inhibitory concentration (MIC)  = 1.6 µM) to Pis-1 (average MIC  = 1.5 µM). However, it exhibited much lower cytotoxicity than Pis-1. Lys10-substituted analogs, Pis-F1K/V10K, Pis-F2K/V10K, and Pis-F6K/V10K in which Lys was substituted for Phe retained antibacterial activity toward standard and drug-resistant bacterial strains with novel bacterial cell selectivity. They exert anti-inflammatory activities via inhibition of nitric oxide production, TNF-α secretion, and MIP-1 and MIP-2 production. They may disrupt the binding of LPS to toll-like receptors, eventually suppressing MAPKs-mediated signaling

  10. Small cationic antimicrobial peptidomimetics: emerging candidate for the development of potential anti-infective agents.

    PubMed

    Lohan, Sandeep; Bisht, Gopal Singh

    2013-01-01

    Rapid increase in the emergence and spread of microbes resistant to conventionally used antibiotics has become a major threat to global health care. Antimicrobial peptides (AMPs) are considered as a potential source of novel antibiotics because of their numerous advantages such as broad-spectrum activity, lower tendency to induce resistance, immunomodulatory response and unique mode of action. However, AMPs have several drawbacks such as; susceptibility to protease degradation, toxicity and high costs of manufacturing. Therefore, extensive research efforts are underway to explore the therapeutic potential of these fascinating natural compounds. This review highlights the potential of small cationic antimicrobial peptidomimetics (SCAMPs; M.W. ≅ 700 Da) as new generation antibiotics. In particular, we focused on recently identified small active pharmacophore from bulky templates of native AMPs, β-peptides, and lipopeptides. In addition, various design strategies recently undertaken to improve the physicochemical properties (proteolytic stability & plasma protein binding) of small cationic peptides have also been discussed.

  11. Synthesis and biological evaluation of some novel tetrahydroquinolines as anticancer and antimicrobial agents.

    PubMed

    Faidallah, Hassan M; Saqer, Alaa A; Alamry, Khalid A; Khan, Khalid A; Asiri, Abdullah M

    2014-06-01

    This study reports the synthesis of a series of new 2-amino-3-cyano-8-methyl-4-substituted-5,6,7,8-tetrahydroquinolines along with some derived fused-ring systems. Ten compounds have shown remarkable cytotoxic activity against human colon carcinoma HT29, hepatocellular carcinoma HepG2 and Caucasian breast adenocarcinoma MCF7 cell lines. Six compounds showed considerable broad-spectrum cytotoxic activity among which two proved to be the most active derivatives. Likewise, seven compounds from the series were found to exhibit significant antimicrobial activity and three of them proved to be the most active candidates. Two alkylthio-pyrimido quinolines are suggested as possible antimicrobial and anticancer candidates in the present series.

  12. Synthesis, molecular modeling and structural characterization of vanillin derivatives as antimicrobial agents

    NASA Astrophysics Data System (ADS)

    Sun, Juan; Yin, Yong; Sheng, Gui-Hua; Yang, Zhi-Bo; Zhu, Hai-Liang

    2013-05-01

    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.

  13. Synthesis of certain 2-substituted-1H-benzimidazole derivatives as antimicrobial and cytotoxic agents.

    PubMed

    Taher, Azza Taher; Khalil, Nadia Abdalla; Ahmed, Eman Mohamed; Ragab, Yasser Mohamed

    2012-01-01

    A series of 2-substituted-1H-benzimidazole derivatives were synthesized and evaluated for antimicrobial, antifungal and cytotoxic activities. The results showed that all tested compounds showed potent antimicrobial activity against some species of Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli, Salmonella typhi) and fungi (Candida albicans) with minimum inhibitory concentrations (MICs) lower than 0.016 µg/mL. In contrast, all tested compounds were inactive against Staphylococcus aureus (Gram-positive bacterium). The final targets were also tested for their antitumor activity in vitro on cervical carcinoma (HeLa) cell line. Eight of the test compounds displayed more potent cytotoxic effect than doxorubicin at nanomolar concentrations. Compounds 2c and 3c exerted the strongest cytoyoxic effect with IC(50) 15 and 13 nM, respectively.

  14. Adaptive resistance to biocides in Salmonella enterica and Escherichia coli O157 and cross-resistance to antimicrobial agents.

    PubMed

    Braoudaki, M; Hilton, A C

    2004-01-01

    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 antimicrobial agents 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 antimicrobial agents, 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.

  15. Combination Antimicrobial Nanocomposite Materials for Neutralization of Biological Threat Agents (PREPRINT)

    DTIC Science & Technology

    2008-09-01

    Kathe, A.A., Varadarajan, P.V., Nachane, R.P., and R.H. Balasubramanya. 2007. Silver-protein (core-shell) nanoparticle production using spent mushroom ... production of nanometric structures and inspiration for a burgeoning branch of materials science (6-9). For example, peptides based on the silaffin... products offer effective antimicrobial activity and demonstrate the facile integration of biomolecules into devices and instruments. These novel

  16. Influence of radiopacifying agents on the solubility, pH and antimicrobial activity of portland cement.

    PubMed

    Weckwerth, Paulo Henrique; Machado, Adriano Cosme de Oliveira; Kuga, Milton Carlos; Vivan, Rodrigo Ricci; Polleto, Raquel da Silva; Duarte, Marco Antonio Hungaro

    2012-01-01

    The aim of this study was to evaluate the interference of the radiopacifiers bismuth oxide (BO), bismuth carbonate (BC), bismuth subnitrate (BS), and zirconiun oxide (ZO) on the solubility, alkalinity and antimicrobial properties of white Portland cement (WPC). The substances were incorporated to PC, at a ratio of 1:4 (v/v) and subjected to a solubility test. To evaluate the pH, the cements were inserted into retrograde cavities prepared in simulated acrylic teeth and immediately immersed in deionized water. The pH of the solution was measured at 3, 24, 72 and 168 h. The antimicrobial activity was evaluated by a radial diffusion method against the microorganisms S. aureus (ATCC 25923), P. aeruginosa (ATCC 27853), E. faecalis (ATCC 29212) and C. albicans (ATCC 10231). The zone of microbial growth inhibition was measured after 24 h. The addition of BS and BC increased the solubility of the cement. The pH values demonstrated that all materials produced alkaline levels. At 3 h, BS showed lower pH than WPC (p<0.05). At 168 h, all materials showed similar pHs (p>0.05). The materials did not present antimicrobial activity for S. aureus, P. aeruginosas and E. faecalis (p>0.05). With regards to C. albicans, all materials formed an inhibition zone, mainly the mixture of WPC with ZO (p<0.05). The type of radiopacifier incorporated into WPC interfered with its physical and antimicrobial properties. ZO was found to be a viable radiopacifier that can be used with WPC.

  17. Hydrothermally derived water-dispersible mixed valence copper-chitosan nanocomposite as exceptionally potent antimicrobial agent

    NASA Astrophysics Data System (ADS)

    Basumallick, Srijita; Rajasekaran, Parthiban; Tetard, Laurene; Santra, Swadeshmukul

    2014-10-01

    We report, for the first time, a one-step hydrothermal (HT) process to design and synthesize water-dispersible chitosan nanoparticles loaded with mixed valence copper. Interestingly, this HT copper-chitosan biocompatible composite exhibits exceptionally high antimicrobial properties. A comprehensive characterization of the composite indicates that the hydrothermal process results in the formation of monodispersed nanoparticles with average size of 40 ± 10 nm. FT-IR and Raman spectroscopic studies unveiled that the hydrolysis of the glycoside bonds as the origin of the depolymerization of chitosan. Furthermore, X-Ray Photoelectron Spectroscopy measurements confirmed the presence of mixed valence copper states in the composite, while UV-Vis and FT-IR studies revealed the chemical interaction of copper with the chitosan matrix. Hence, the extensive spectroscopic data provide strong evidence that the chitosan structure was rearranged to capture copper oxide nanoparticles. Finally, HT copper-chitosan composite showed a complete killing effect when tested against both Gram negative ( E. coli) and Gram positive ( S. aureus) bacteria at metallic copper concentration of 100 μg/ml (1.57 mM). At the same concentration, neither pure chitosan nor copper elicited such antimicrobial efficacy. Thus, we show that HT process significantly enhances the synergistic antimicrobial effect of chitosan and copper in addition to increasing the water dispersibility.

  18. Antimicrobial Polymer

    DOEpatents

    McDonald, William F.; Wright, Stacy C.; Taylor, Andrew C.

    2004-09-28

    A polymeric composition having antimicrobial properties and a process for rendering the surface of a substrate antimicrobial are disclosed. The polymeric composition comprises a crosslinked chemical combination of (i) a polymer having amino group-containing side chains along a backbone forming the polymer, (ii) an antimicrobial agent selected from metals, metal alloys, metal salts, metal complexes and mixtures thereof, and (iii) a crosslinking agent containing functional groups capable of reacting with the amino groups. In one example embodiment, the polymer is a polyamide formed from a maleic anhydride or maleic acid ester monomer and alkylamines thereby producing a polyamide having amino substituted alkyl chains on one side of the polyamide backbone; the crosslinking agent is a phosphine having the general formula (A).sub.3 P wherein A is hydroxyalkyl; and the metallic antimicrobial agent is selected from chelated silver ions, silver metal, chelated copper ions, copper metal, chelated zinc ions, zinc metal and mixtures thereof.

  19. Comparison of risk-based versus random sampling in the monitoring of antimicrobial residues in Danish finishing pigs.

    PubMed

    Alban, Lis; Rugbjerg, Helene; Petersen, Jesper Valentin; Nielsen, Liza Rosenbaum

    2016-06-01

    In Denmark, a monitoring program for residues of antimicrobials in pork is in place involving annual testing of around 20,000 samples from finishing pigs corresponding to 0.1% of the animals slaughtered. Annually, zero to two samples are found above the maximum residue limit. Both authorities and industry have expressed interest in adjusting the monitoring to a risk-based system. The objective of this study was to assess the opportunities and consequences of the monitoring considering: 1) replacing the current bioassay with high-performance liquid chromatography-mass spectrometry (HPLC LC-MS/MS), 2) replacing kidney with muscles as sample matrix, and 3) using indicators to identify high-risk (HR) herds and increase sampling intensity in these herds, lowering sampling in the low-risk (LR) herds, while aiming at continued detection of similar numbers of test-positives at the lowest possible costs. A state-of-the-art stochastic scenario tree modelling approach including economic evaluation of different model outcomes was used. A total of six scenarios were run for penicillin and tetracycline, respectively. Relevant information was obtained through the literature, statistical analysis of existing data as well as consultations with laboratory and slaughterhouse experts. Abattoir recordings of chronic pleuritis were used as an indicator for finishing pig herds (HR=within-herd prevalence>40%). Such risk-based monitoring would have to use muscles and not kidneys, because of logistic challenges in identifying and storing of plucks until testing. However, the bioassay cannot be used on muscle tissue due to low sensitivity for tetracyclines. Different plausible combinations of sample sizes were also modelled. The HPLC LC-MS/MS method detected the same number of cases compared to the bioassay when kidney was used as matrix. HPLC LC-MS/MS has a higher sensitivity when used on muscle but it is almost twice as costly as the bioassay. Risk-based sampling resulted in detection of

  20. Susceptibility of Pittsburgh pneumonia agent (Legionella micdadei) and other newly recognized members of the genus Legionella to nineteen antimicrobial agents.

    PubMed Central

    Pasculle, A W; Dowling, J N; Weyant, R S; Sniffen, J M; Cordes, L G; Gorman, G M; Feeley, J C

    1981-01-01

    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

  1. In vitro evaluation of aliphatic fatty alcohol metabolites of Perseaamericana seed as potential antimalarial and antimicrobial agents

    PubMed Central

    Falodun, A.; Erharuyi, O.; Imieje, V.; Ahomafor, J.; Akunyuli, C.; Jacobs, M.; Khan, S.; Hamann, M. T.; Langer, P.

    2016-01-01

    Perseaamericana Mill (Lauraceae) is a local medicinal plant used in Nigerian ethnomedicine as antimalarial. The aqueous decoction of the root part is a potent remedy against bacterial infections. Hence, the need to investigate the phytochemical and biological activities (antimicrobial and antiplasmodial) of the root back of Perseaamericana. Chromatographic and spectroscopic techniques were used in the identification and purification of metabolites, which were assayed for antimalarial and antimicrobial activities using Plasmodium falciparum and a panel of microorganisms. From the seeds of P. americana, five known 1, 2, 4-dihydroxy derivatives aliphatic alcohols, called avocadenols were isolated and identified by spectroscopic methods including 1D- and 2D NMR, and comparison with reported data in literature. Antifungal activity for 1, 2, 4-Trihydroxyheptadec-6-en-16-yne (5) (IC50< 8 μg/mL) against all the fungal strains and S. areus, and antimalarial activity for compounds 1, 2, 4-Trihydroxyheptadec-16-ene (1) and 1, 2, 4-tetrahydroxyheptadecane-6, 16-diene(2) (IC50 = 1.6 and 1.4 μg/mL for the D6 clone, respectively, and 2.1 and 1.4 μg/mL for the W2 clone, respectively) was observed. The fatty alcohols 1, 2, 4-tetrahydroxyheptadecane-6, 16-diene(2); 1, 2, 4-Trihydroxyheptadec-16-yne(3) and 1, 2, 4-Trihydroxyheptadecane(4) also exhibited promising in vitro antibacterial activity against a panel of pathogenic bacteria S. areus, methicillin resistant S. areus and E. coli at IC50 values of 21.1, 8, 200 μg/mL), (3.259, 86.32 μg/mL) and (17.18, 8.26 and 200 μg/mL), respectively. The results of this study provide evidence that the fatty alcohols are a promising class of antimalarial and antimicrobial agents. PMID:28042193

  2. Synthesis of some novel pyrazolo[3,4-d] pyrimidin-4(5H)-one derivatives as potential antimicrobial agent

    PubMed Central

    Sureja, Dipen K.; Dholakia, Sandip P.; Vadalia, Kantilal R.

    2016-01-01

    Objectives: The aim of the present work was to synthesize a novel series of pyrazolo[3,4-d]pyrimidin-4(5H)-one derivatives and evaluate their in vitro antimicrobial activity. Methods: Cyclization of an ortho-amino ester of 1-(2,4-dinitrophenyl)pyrazole with various aliphatic/aromatic nitriles under different reaction conditions such as conventional and microwave assisted synthesis, provided pyrazolo[3,4-d] pyrimidin-4(5H)-one derivatives. All the synthesized compounds were evaluated in vitro for their antimicrobial activity against selected bacteria and fungi by agar well diffusion method. Results: All newly synthesized compounds were characterized using spectral and elemental analysis. Compounds 2e, 2f, and 2g showed significant antimicrobial activity as compared to standard drugs used. Conclusion: The newly synthesized compounds could be useful templates for the design and optimization of more active analogs as a possible antimicrobial agent. PMID:28216957

  3. Synthesis, Biological Evaluation and 2D-QSAR Study of Halophenyl Bis-Hydrazones as Antimicrobial and Antitubercular Agents

    PubMed Central

    Abdel-Aziz, Hatem A.; Eldehna, Wagdy M.; Fares, Mohamed; Al-Rashood, Sara T. A.; Al-Rashood, Khalid A.; Abdel-Aziz, Marwa M.; Soliman, Dalia H.

    2015-01-01

    In continuation of our endeavor towards the development of potent and effective antimicrobial agents, three series of halophenyl bis-hydrazones (14a–n, 16a–d, 17a and 17b) were synthesized and evaluated for their potential antibacterial, antifungal and antimycobacterial activities. These efforts led to the identification of five molecules 14c, 14g, 16b, 17a and 17b (MIC range from 0.12 to 7.81 μg/mL) with broad antimicrobial activity against Mycobacterium tuberculosis; Aspergillus fumigates; Gram positive bacteria, Staphylococcus aureus, Streptococcus pneumonia, and Bacillis subtilis; and Gram negative bacteria, Salmonella typhimurium, Klebsiella pneumonia, and Escherichia coli. Three of the most active compounds, 16b, 17a and 17b, were also devoid of apparent cytotoxicity to lung cancer cell line A549. Amphotericin B and ciprofloxacin were used as references for antifungal and antibacterial screening, while isoniazid and pyrazinamide were used as references for antimycobacterial activity. Furthermore, three Quantitative Structure Activity Relationship (QSAR) models were built to explore the structural requirements controlling the different activities of the prepared bis-hydrazones. PMID:25903147

  4. Evaluation of antimicrobial activity of glycerol monolaurate nanocapsules against American foulbrood disease agent and toxicity on bees.

    PubMed

    Lopes, Leonardo Q S; Santos, Cayane G; de Almeida Vaucher, Rodrigo; Gende, Liesel; Raffin, Renata P; Santos, Roberto C V

    2016-08-01

    The American Foulbrood Disease (AFB) is a fatal larval bee infection. The etiologic agent is the bacterium Paenibacillus larvae. The treatment involves incineration of all contaminated materials, leading to high losses. The Glycerol Monolaurate (GML) is a known antimicrobial potential compound, however its use is reduced due to its low solubility in water and high melting point. The nanoencapsulation of some drugs offers several advantages like improved stability and solubility in water. The present study aimed to evaluate the antimicrobial activity against P. larvae and the toxicity in bees of GML nanoparticles. The nanocapsules were produced and presented mean diameter of 210 nm, polydispersity index of 0.044, and zeta potential of -23.4 mV demonstrating the acceptable values to predict a stable system. The microdilution assay showed that it is necessary 142 and 285 μg/mL of GML nanocapsules to obtain a bacteriostatic and bactericidal effect respectively. The time-kill curve showed the controlled release of compound, exterminating the microorganism after 24 h. The GML nanocapsules were able to kill the spore form of Paenibacillus larvae while the GML do not cause any effect. The assay in bees showed that the GML has a high toxicity while the GML nanoparticles showed a decrease on toxic effects. Concluding, the formulation shows positive results in the action to combat AFB besides not causing damage to bees.

  5. Construction of Zinc Oxide into Different Morphological Structures to Be Utilized as Antimicrobial Agent against Multidrug Resistant Bacteria

    PubMed Central

    Elkady, M. F.; Shokry Hassan, H.; Hafez, Elsayed E.; Fouad, Ahmed

    2015-01-01

    Nano-ZnO has been successfully implemented in particles, rods, and tubes nanostructures via sol-gel and hydrothermal techniques. The variation of the different preparation parameters such as reaction temperature, time, and stabilizer agents was optimized to attain different morphological structures. The influence of the microwave annealing process on ZnO crystallinity, surface area, and morphological structure was monitored using XRD, BET, and SEM techniques, respectively. The antimicrobial activity of zinc oxide produced in nanotubes structure was examined against four different multidrug resistant bacteria: Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) strains. The activity of produced nano-ZnO was determined by disc diffusion technique and the results revealed that ZnO nanotubes recorded high activity against the studied strains due to their high surface area equivalent to 17.8 m2/g. The minimum inhibitory concentration (MIC) of ZnO nanotubes showed that the low concentrations of ZnO nanotubes could be a substitution for the commercial antibiotics when approached in suitable formula. Although the annealing process of ZnO improves the degree of material crystallinity, however, it declines its surface area and consequently its antimicrobial activity. PMID:26451136

  6. Effects of different surface modifying agents on the cytotoxic and antimicrobial properties of ZnO nanoparticles.

    PubMed

    Esparza-González, S C; Sánchez-Valdés, S; Ramírez-Barrón, S N; Loera-Arias, M J; Bernal, J; Meléndez-Ortiz, H Iván; Betancourt-Galindo, R

    2016-12-01

    Zinc oxide (ZnO) nanoparticles (NPs) have received considerable attention in the medical field because of their antibacterial properties, primarily for killing and reducing the activity of numerous microorganisms. The purpose of this study was to determine whether surface-modified ZnO NPs exhibit different properties compared with unmodified ZnO. The antimicrobial and cytotoxic properties of modified ZnO NPs as well as their effects on inflammatory cytokine production were evaluated. ZnO NPs were prepared using a wet chemical method. Then, the surfaces of these NPs were modified using 3-aminopropyltriethoxysilane (APTES) and dimethyl sulfoxide (DMSO) as modifying agents via a chemical hydrolysis method. According to infrared spectroscopy analysis (FTIR), the structure of the ZnO remained unchanged after modification. Antibacterial assays demonstrated that APTES modification is more effective at inducing an antimicrobial effect against Gram-negative bacteria than against Gram-positive bacteria. Cytotoxicity studies showed that cell viability was dose-dependent; moreover, pristine and APTES-modified ZnO exhibited low cytotoxicity, whereas DMSO-modified ZnO exhibited toxicity even at a low NP concentration. An investigation of inflammatory cytokine production demonstrated that the extent of stimulation was related to the ZnO NP concentration but not to the surface modification, except for IFN-γ and IL-10, which were not detected even at high NP concentrations.

  7. Evaluation of bishexadecyltrimethyl ammonium palladium tetrachloride based dual functional colloidal carrier as an antimicrobial and anticancer agent.

    PubMed

    Kaur, Gurpreet; Kumar, Sandeep; Dilbaghi, Neeraj; Kaur, Baljinder; Kant, Ravi; Guru, Santosh Kumar; Bhushan, Shashi; Jaglan, Sundeep

    2016-04-21

    We have developed a dual function carrier using bishexadecyltrimethyl ammonium palladium tetrachloride, which has anticancer as well as antibacterial activity, using a ligand insertion method with a simple and easy work procedure. The complex is prepared by a simple and cost effective method using hexadecyltrimethyl ammonium chloride and palladium chloride under controlled stoichiometry. Herein, we report the aggregation (self assembly) of the metallosurfactant having palladium as a counter ion, in aqueous medium along with its binding affinity with bovine serum albumin. The palladium surfactant has exhibited excellent antimicrobial efficacy against fungus and bacteria (both Gram-positive and Gram-negative bacteria). Cytotoxicity of palladium surfactant against cancerous (Human leukemia HL-60, pancreatic MIA-Pa-Ca-2 and prostate cancer PC-3) and healthy cells (fR2 human breast epithelial cells) was also evaluated using MTT assay. The present dual functional moiety shows a low IC50 value and has potential to be used as an anticancer agent. Our dual function carrier which itself possesses antimicrobial and anticancer activity represents a simple and effective system and can also be utilized as a drug carrier in the future.

  8. Radiosensitivities of parabens and characterization of the radical species induced in this class of antimicrobial agents after gamma irradiation

    NASA Astrophysics Data System (ADS)

    Üstündaǧ, Ilknur; Korkmaz, Özden

    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 antimicrobial agents in food, cosmetics and drugs to be sterilized by radiation without much loss from their antimicrobial activities.

  9. Reduced Susceptibility to Rifampicin and Resistance to Multiple Antimicrobial Agents among Brucella abortus Isolates from Cattle in Brazil

    PubMed Central

    Barbosa Pauletti, Rebeca; Reinato Stynen, Ana Paula; Pinto da Silva Mol, Juliana; Seles Dorneles, Elaine Maria; Alves, Telma Maria; de Sousa Moura Souto, Monalisa; Minharro, Silvia; Heinemann, Marcos Bryan; Lage, Andrey Pereira

    2015-01-01

    This study aimed to determine the susceptibility profile of Brazilian Brucella abortus isolates from cattle to eight antimicrobial agents that are recommended for the treatment of human brucellosis and to correlate the susceptibility patterns with origin, biotype and MLVA16-genotype of the strains. Screening of 147 B. abortus strains showed 100% sensitivity to doxycycline and ofloxacin, one (0.68%) strain resistant to ciprofloxacin, two strains (1.36%) resistant to streptomycin, two strains (1.36%) resistant to trimethoprim-sulfamethoxazole and five strains (3.40%) resistant to gentamicin. For rifampicin, three strains (2.04%) were resistant and 54 strains (36.73%) showed reduced sensitivity. Two strains were considered multidrug resistant. In conclusion, the majority of B. abortus strains isolated from cattle in Brazil were sensitive to the antimicrobials commonly used for the treatment of human brucellosis; however, a considerable proportion of strains showed reduced susceptibility to rifampicin and two strains were considered multidrug resistant. Moreover, there was no correlation among the drug susceptibility pattern, origin, biotype and MLVA16-genotypes of these strains. PMID:26181775

  10. Reduced Susceptibility to Rifampicin and Resistance to Multiple Antimicrobial Agents among Brucella abortus Isolates from Cattle in Brazil.

    PubMed

    Barbosa Pauletti, Rebeca; Reinato Stynen, Ana Paula; Pinto da Silva Mol, Juliana; Seles Dorneles, Elaine Maria; Alves, Telma Maria; de Sousa Moura Souto, Monalisa; Minharro, Silvia; Heinemann, Marcos Bryan; Lage, Andrey Pereira

    2015-01-01

    This study aimed to determine the susceptibility profile of Brazilian Brucella abortus isolates from cattle to eight antimicrobial agents that are recommended for the treatment of human brucellosis and to correlate the susceptibility patterns with origin, biotype and MLVA16-genotype of the strains. Screening of 147 B. abortus strains showed 100% sensitivity to doxycycline and ofloxacin, one (0.68%) strain resistant to ciprofloxacin, two strains (1.36%) resistant to streptomycin, two strains (1.36%) resistant to trimethoprim-sulfamethoxazole and five strains (3.40%) resistant to gentamicin. For rifampicin, three strains (2.04%) were resistant and 54 strains (36.73%) showed reduced sensitivity. Two strains were considered multidrug resistant. In conclusion, the majority of B. abortus strains isolated from cattle in Brazil were sensitive to the antimicrobials commonly used for the treatment of human brucellosis; however, a considerable proportion of strains showed reduced susceptibility to rifampicin and two strains were considered multidrug resistant. Moreover, there was no correlation among the drug susceptibility pattern, origin, biotype and MLVA16-genotypes of these strains.

  11. Motuporamine Derivatives as Antimicrobial Agents and Antibiotic Enhancers against Resistant Gram‐Negative Bacteria

    PubMed Central

    Borselli, Diane; Blanchet, Marine; Bolla, Jean‐Michel; Muth, Aaron; Skruber, Kristen

    2017-01-01

    Abstract Dihydromotuporamine C and its derivatives were evaluated for their in vitro antimicrobial activities and antibiotic enhancement properties against Gram‐negative bacteria and clinical isolates. The mechanism of action of one of these derivatives, MOTU‐N44, was investigated against Enterobacter aerogenes by using fluorescent dyes to evaluate outer‐membrane depolarization and permeabilization. Its efficiency correlated with inhibition of dye transport, thus suggesting that these molecules inhibit drug transporters by de‐energization of the efflux pump rather than by direct interaction of the molecule with the pump. This suggests that depowering the efflux pump provides another strategy to address antibiotic resistance. PMID:28098416

  12. In Vitro Synergism between Azithromycin or Terbinafine and Topical Antimicrobial Agents against Pythium insidiosum

    PubMed Central

    Itaqui, Sabrina R.; Verdi, Camila M.; Tondolo, Juliana S. M.; da Luz, Thaisa S.; Alves, Sydney H.; Santurio, Janio M.

    2016-01-01

    We describe here in vitro activity for the combination of azithromycin or terbinafine and benzalkonium, cetrimide, cetylpyridinium, mupirocin, triclosan, or potassium permanganate. With the exception of potassium permanganate, the remaining antimicrobial drugs were active and had an MIC90 between 2 and 32 μg∕ml. The greatest synergism was observed for the combination of terbinafine and cetrimide (71.4%). In vivo experimental evaluations will clarify the potential of these drugs for the topical treatment of lesions caused by Pythium insidiosum. PMID:27216049

  13. In vitro data support the investigation of vinegar as an antimicrobial agent for PD-associated Pseudomonas exit site infections.

    PubMed

    Carson, Christine F; Ash, Oliver; Chakera, Aron

    2017-02-01

    Peritoneal dialysis exit site infections caused by Pseudomonas spp. are difficult to treat and can lead to peritonitis and/or modality failure. Effective alternative or adjunct non-antibiotic antimicrobial agents could improve treatment as well as reduce the use of antibiotics and contribute to a reduction in antibiotic selection pressure and the further development of antibiotic resistance. Vinegar is popularly promoted as a topical antimicrobial agent and has been recommended as an adjunct treatment for Pseudomonas exit site infections in PD patients. Systematic empirical data on the susceptibility of pseudomonads to vinegar are lacking. This study aimed to determine the susceptibility to vinegar of 57 isolates of Pseudomonas. The MICs and MBCs of four vinegars were determined for clinical, environmental and/or reference isolates of P. aeruginosa (n = 34), P. fluorescens (n = 11) and P. putida (n = 12) using a broth microdilution method. The MIC90 and MBC90 were also determined for each species. The MIC90 of all four vinegars against P. aeruginosa was 2% (vol/vol). The MBC90 was 8%. The MIC90 s for P. fluorescens and P. putida were also 2%. The MIC90 s were 4%. Dilutions of vinegar recommended for the treatment of Pseudomonas exit site infections have in vitro activity against these notoriously resistant bacteria. In light of increasing rates of antibiotic resistance and the need to reduce antibiotic selection pressure as part of good antibiotic stewardship, the efficacy of vinegar, or its active constituent acetic acid, for the treatment of Pseudomonas exit site infections should be investigated further.

  14. Effect of Different Obturation Materials on Residual Antimicrobial Activity of 2% Chlorhexidine in Dentin at Different Time Intervals: An Ex Vivo Study

    PubMed Central

    Bolhari, Behnam; Dehghan, Somayyeh; Sharifian, Mohammad Reza; Bahador, Abbas

    2015-01-01

    Objectives: The aim of this study was to evaluate the effect of gutta percha/AH26 and Resilon/RealSeal SE on residual antimicrobial activity of chlorhexidine (CHX) in human root dentin and suggest the best filling material when CHX is used as final irrigant. Materials and Methods: One-hundred and forty-four single-rooted human teeth were selected for this study. Canals were instrumented to the apical size #35. Smear layer was removed using 5.25% NaOCl and 17% EDTA and then 108 teeth were irrigated with 2% CHX and randomly divided into three groups of gutta percha/AH26, Resilon/RealSeal SE and positive controls. Each group was divided into three subgroups for different time intervals (one, three and six weeks). Thirty-six teeth, as negative controls, were irrigated with saline and obturated with gutta percha/AH26 and Resilon/RealSeal SE. Dentin powder was prepared at the afore-mentioned intervals. After exposure to Enterococcus faecalis for 24 hours, colony forming units (CFUs) were counted and residual antimicrobial activity was calculated. The data were analyzed using the Kruskal Wallis test and one-way ANOVA. The significance level was set at P<0.05. Results: The antimicrobial activity of CHX gradually decreased in a time-dependent manner but it maintained over 95% of its antimicrobial activity after six weeks. Moreover, Resilon/RealSeal SE significantly decreased the antimicrobial activity of CHX in comparison with gutta-percha/AH26 (P<0.05). Conclusion: After a final irrigation with CHX, gutta-percha/AH26 is a better choice for root canal obturation. PMID:27252755

  15. New Biofunctional Loading of Natural Antimicrobial Agent in Biodegradable Polymeric Films for Biomedical Applications

    PubMed Central

    Ghafoor, Bakhtawar; Ansari, Umar; Bhatti, Muhammad Faraz; Akhtar, Hafsah; Darakhshan, Fatima

    2016-01-01

    The study focuses on the development of novel Aloe vera based polymeric composite films and antimicrobial suture coatings. Polyvinyl alcohol (PVA), a synthetic biocompatible and biodegradable polymer, was combined with Aloe vera, a natural herb used for soothing burning effects and cosmetic purposes. The properties of these two materials were combined together to get additional benefits such as wound healing and prevention of surgical site infections. PVA and Aloe vera were mixed in a fixed quantity to produce polymer based films. The films were screened for antibacterial and antifungal activity against bacterial (E. coli, P. aeruginosa) and fungal strains (Aspergillus flavus and Aspergillus tubingensis) screened. Aloe vera based PVA films showed antimicrobial activity against all the strains; the lowest Aloe vera concentration (5%) showed the highest activity against all the strains. In vitro degradation and release profile of these films was also evaluated. The coating for sutures was prepared, in vitro antibacterial tests of these coated sutures were carried out, and later on in vivo studies of these coated sutures were also performed. The results showed that sutures coated with Aloe vera/PVA coating solution have antibacterial effects and thus have the potential to be used in the prevention of surgical site infections and Aloe vera/PVA based films have the potential to be used for wound healing purposes. PMID:27965710

  16. A fermentation assay to evaluate the effectiveness of antimicrobial agents on gut microflora.

    PubMed

    Shanmugavelu, S; Ruzickova, G; Zrustova, J; Brooker, J D

    2006-10-01

    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 tested in antimicrobial assays against C. perfringens; the minimum inhibitory concentration for each essential oil and condensed tannin was determined. The effect of penicillin-G on C. perfringens, in both growth and fermentation assays, was similar, and for all secondary metabolites tested, concentrations that inhibited fermentation were also bacteriocidal. The assay was also used to demonstrate the effect of dietary composition and enzyme supplementation on fermentation of mixed gut microflora in vitro; results are compared with in vivo results for the same dietary treatments. The data demonstrate that the effects of bioactive secondary plant products and feed composition on individual organisms or mixed gut microflora can be tested by analysis of fermentative activity in vitro, and that this provides a rapid assay for testing potential poultry feed additives before in vivo trials.

  17. Wood ants produce a potent antimicrobial agent by applying formic acid on tree-collected resin.

    PubMed

    Brütsch, Timothée; Jaffuel, Geoffrey; Vallat, Armelle; Turlings, Ted C J; Chapuisat, Michel

    2017-04-01

    Wood ants fight pathogens by incorporating tree resin with antimicrobial properties into their nests. They also produce large quantities of formic acid in their venom gland, which they readily spray to defend or disinfect their nest. Mixing chemicals to produce powerful antibiotics is common practice in human medicine, yet evidence for the use of such "defensive cocktails" by animals remains scant. Here, we test the hypothesis that wood ants enhance the antifungal activity of tree resin by treating it with formic acid. In a series of experiments, we document that (i) tree resin had much higher inhibitory activity against the common entomopathogenic fungus Metarhizium brunneum after having been in contact with ants, while no such effect was detected for other nest materials; (ii) wood ants applied significant amounts of endogenous formic and succinic acid on resin and other nest materials; and (iii) the application of synthetic formic acid greatly increased the antifungal activity of resin, but had no such effect when applied to inert glass material. Together, these results demonstrate that wood ants obtain an effective protection against a detrimental microorganism by mixing endogenous and plant-acquired chemical defenses. In conclusion, the ability to synergistically combine antimicrobial substances of diverse origins is not restricted to humans and may play an important role in insect societies.

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

    NASA Astrophysics Data System (ADS)

    Lusebrink, Inka; Dettner, Konrad; Seifert, Karlheinz

    2008-08-01

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

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

    PubMed

    Herman, Anna; Herman, Andrzej Przemysław; Domagalska, Beata Wanda; Młynarczyk, Andrzej

    2013-06-01

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

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

    PubMed

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

    2010-10-01

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

  1. Spectrum of antimicrobial activity and user acceptability of the hand disinfectant agent Sterillium Gel.

    PubMed

    Kampf, G; Rudolf, M; Labadie, J-C; Barrett, S P

    2002-10-01

    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 Escherichia coli (suspension test) and EN 1500 (15 volunteers; four replicates), fungicidal activity according to EN 1275 against Candida albicans and spores of Aspergillus niger (suspension test) and tuberculocidal activity against Mycobacterium terrae using the DGHM suspension test. Virucidal activity was determined in suspension tests based on reduction of infectivity with and without interfering substances (10% fetal calf serum; 0.3% erythrocytes and 0.3% bovine serum albumin). Ninety-six healthcare workers in hospitals in France and the UK used the gel for four weeks and assessed it by filling out a questionnaire. The gel was bactericidal (a reduction factor of > 10(5)-fold), tuberculocidal (reduction factor > 10(5)) and fungicidal (reduction factor > 10(4)) in 30 s. Irrespective of interfering substances the gel inactivated orthopoxvirus and herpes simplex virus type 1 and 2 in 15 s, adenovirus in 2 min, poliovirus in 3 min and papovavirus in 15 min by a factor of > 10(4)-fold. Rotavirus and human immunodeficiency virus were inactivated in 30 s (without interfering substances). Under practical use conditions it was as effective in 30 s as the reference alcohol in 60 s. Most users described the tackiness, aggregation, skin feeling after use and smell as positive or acceptable. A total of 65.6% assessed the new gel to be better than a comparator irrespective of its type (gel or liquid). Overall Sterillium Gel had a unique spectrum of antimicrobial activity. It is probably the first alcohol-based hand gel to pass EN 1500 in 30 s. Due to the

  2. Mitigating the antimicrobial activities of selected organic acids and commercial sanitizers with various neutralizing agents.

    PubMed

    Park, Yoen Ju; Chen, Jinru

    2011-05-01

    This study was conducted to evaluate the abilities of five neutralizing agents, Dey-Engley (DE) neutralizing broth (single or double strength), morpholinepropanesulfonic acid (MOPS) buffer, phosphate-buffered saline (PBS), and sodium thiosulfate buffer, in mitigating the activities of acetic or lactic acid (2%) and an alkaline or acidic sanitizer (a manufacturer-recommended concentration) againt the cells of Shiga toxin-producing Escherichia coli (STEC; n = 9). To evaluate the possible toxicity of the neutralizing agents to the STEC cells, each STEC strain was exposed to each of the neutralizing agents at room temperature for 10 min. Neutralizing efficacy was evaluated by placing each STEC strain in a mixture of sanitizer and neutralizer under the same conditions. The neutralizing agents had no detectable toxic effect on the STEC strains. PBS was least effective for neutralizing the activity of selected organic acids and sanitizers. Single-strength DE and sodium thiosulfate neutralized the activity of both acetic and lactic acids. MOPS buffer neutralized the activity of acetic acid and lactic acid against six and five STEC strains, respectively. All neutralizing agents, except double-strength DE broth, had a limited neutralizing effect on the activity of the commercial sanitizers used in the study. The double-strength DE broth effectively neutralized the activity of the two commercial sanitizers with no detectable toxic effects on STEC cells.

  3. Actinomyces pyogenes: susceptibility of 103 clinical animal isolates to 22 antimicrobial agents.

    PubMed

    Guérin-Faublée, V; Flandrois, J P; Broye, E; Tupin, F; Richard, Y

    1993-01-01

    Actinomyces pyogenes induces suppurative diseases in ruminants and many other animal species. Most of the earlier antimicrobial susceptibility data has been obtained by disk diffusion techniques. Minimal inhibitory concentrations (MIC) of 22 antibiotics for 103 strains of A pyogenes of animal origin were determined by agar dilution test (Mueller-Hinton agar supplemented with 5% sheep blood). All the strains were susceptible to penicillin G, amoxicillin, methicillin, cephalothin, cefoperazone, pristinamycin, kanamycin, gentamicin, spectinomycin, chloramphenicol, vancomycin, novobiocin and rifampin. Fifty-nine percent were resistant to streptomycin, 67% to tetracycline, doxycycline and minocycline, 12% to erythromycin, spiramycin and lincomycin. Most of the strains resistant to macrolides and lincosamides exhibited a constitutive MLS(B)-like phenotype. In the cultural conditions used, it was not possible to determine accurate MIC of fucidic acid and pefloxacin.

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

    PubMed

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

    2014-09-01

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

  5. Antimicrobial activity of biodegradable polysaccharide and protein-based films containing active agents.

    PubMed

    Kuorwel, Kuorwel K; Cran, Marlene J; Sonneveld, Kees; Miltz, Joseph; Bigger, Stephen W

    2011-04-01

    Significant interest has emerged in the introduction of food packaging materials manufactured from biodegradable polymers that have the potential to reduce the environmental impacts associated with conventional packaging materials. Current technologies in active packaging enable effective antimicrobial (AM) packaging films to be prepared from biodegradable materials that have been modified and/or blended with different compatible materials and/or plasticisers. A wide range of AM films prepared from modified biodegradable materials have the potential to be used for packaging of various food products. This review examines biodegradable polymers derived from polysaccharides and protein-based materials for their potential use in packaging systems designed for the protection of food products from microbial contamination. A comprehensive table that systematically analyses and categorizes much of the current literature in this area is included in the review.

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

    PubMed

    Todorović, Biljana; Milijasević-Marčić, Svetlana; Potočnik, Ivana; Stepanović, Miloš; Rekanović, Emil; Nikolić-Bujanović, Ljiljana; Cekerevac, Milan

    2012-01-01

    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.

  7. Further investigation of inhibitors of MRSA pyruvate kinase: Towards the conception of novel antimicrobial agents.

    PubMed

    Labrière, Christophe; Gong, Huansheng; Finlay, B Brett; Reiner, Neil E; Young, Robert N

    2017-01-05

    Several novel series of compounds were synthesized and evaluated as inhibitors of methicillin-resistant Staphylococcus aureus (MRSA) pyruvate kinase (PK). PK has been identified as a highly interconnected essential 'hub' protein in MRSA, with structural features distinct from the human homologs which makes it a novel antimicrobial target. Several MRSA PK inhibitors (including the hydrazide 1) were identified using in silico screening combined with enzyme assays and were found to be selective for bacterial enzyme compared to human PK isoforms. Structure-activity relationship (SAR) studies were carried out on the replacement of the hydrazide linker with 3-atoms, 2-atoms and 0-atom linkers and led us to discover more potent compounds with enzyme inhibiting activities in the low nanomolar range and some were found to effectively inhibit bacteria growth in culture with minimum inhibitory concentrations (MIC) as low as 1 μg/mL.

  8. Quaternary ammonium biocides as antimicrobial agents protecting historical wood and brick.

    PubMed

    Rajkowska, Katarzyna; Koziróg, Anna; Otlewska, Anna; Piotrowska, Małgorzata; Nowicka-Krawczyk, Paulina; Brycki, Bogumił; Kunicka-Styczyńska, Alina; Gutarowska, Beata

    2016-01-01

    Quaternary ammonium compounds (QACs) are widely used in disinfection of water, surfaces and instruments as well as in textile, leather and food industries because of their relatively low toxicity, broad antimicrobial spectrum, non-volatility and chemical stability. Due to these advantages, QACs are also used in restoration and can be applied on historical material. The aim of this study was to determine the usefulness of biocides based on quaternary ammonium salts and containing various excipients in the protection of historical materials against microbial growth. The study determined the antimicrobial activity of three biocides against bacteria: Pseudomonas fluorescens, Staphylococcus equorum, Bacillus cereus, Bacillus muralis, Sporosarcina aquimarina and Rhodococcus fascians, and moulds: Chaetomium globosum, Penicillium citreonigrum, Cladosporium cladosporioides I, Acremonium strictum, Aspergillus fumigatus and Cladosporium cladosporioides II, all isolated from historical wood and brick. Staphylococcus equorum, Bacillus cereus, Sporosarcina aquimarina and Rhodococcus fascians bacteria, and Cladosporium cladosporioides I and Acremonium strictum moulds showed high sensitivity to quaternary ammonium biocides. Historical wood can be effectively disinfected by three applications of biocide A (30% v/v) containing dodecyl dimethyl ammonium chloride (DDAC), citric acid, propiconazole and propanol. Disinfection of historical brick can be carried out by three applications of 6% v/v solutions of biocide B (based on DDAC and ethylenediaminetetraacetic acid - EDTA) or biocide C (containing a non-ionic surfactant, DDAC and EDTA). Effective protection of historical building materials against microbial growth for a period of seven days can be achieved by the application of biocide A (30% v/v) on the wood surface and biocide B (6% v/v) on the brick surface.

  9. Alternating Current Electrophoretic Deposition for the Immobilization of Antimicrobial Agents on Titanium Implant Surfaces.

    PubMed

    Braem, Annabel; De Brucker, Katrijn; Delattin, Nicolas; Killian, Manuela S; Roeffaers, Maarten B J; Yoshioka, Tomohiko; Hayakawa, Satoshi; Schmuki, Patrik; Cammue, Bruno P A; Virtanen, Sannakaisa; Thevissen, Karin; Neirinck, Bram

    2017-03-15

    One prominent cause of implant failure is infection; therefore, research is focusing on developing surface coatings that render the surface resistant to colonization by micro-organisms. Permanently attached coatings of antimicrobial molecules are of particular interest because of the reduced cytoxicity and lower risk of developing resistance compared to controlled release coatings. In this study, we focus on the chemical grafting of bioactive molecules on titanium. To concentrate the molecules at the metallic implant surface, we propose electrophoretic deposition (EPD) applying alternating current (AC) signals with an asymmetrical wave shape. We show that for the model molecule bovine serum albumin (BSA), as well as for the clinically relevant antifungal lipopeptide caspofungin (CASP), the deposition yield is drastically improved by superimposing a DC offset in the direction of the high-amplitude peak of the AC signal. Additionally, in order to produce immobilized CASP coatings, this experimental AC/DC-EPD method is combined with an established surface activation protocol. Principle component analysis (PCA) of time-of-flight secondary ion mass spectrometry (ToF-SIMS) data confirm the immobilization of CASP with higher yield as compared to a diffusion-controlled process, and higher purity than the clinical CASP starting suspensions. Scratch testing data indicate good coating adhesion. Importantly, the coatings remain active against the fungal pathogen C. albicans as shown by in vitro biofilm experiments. In summary, this paper delivers a proof-of-concept for the application of AC-EPD as a fast grafting tool for antimicrobial molecules without compromising their activities.

  10. Structure, antimicrobial activity, DNA- and albumin-binding of manganese(II) complexes with the quinolone antimicrobial agents oxolinic acid and enrofloxacin.

    PubMed

    Zampakou, Marianthi; Akrivou, Melpomeni; Andreadou, Eleni G; Raptopoulou, Catherine P; Psycharis, Vassilis; Pantazaki, Anastasia A; Psomas, George

    2013-04-01

    The reaction of MnCl2 with the quinolone antibacterial drug oxolinic acid (Hoxo) results to the formation of [KMn(oxo)3(MeOH)3]. Interaction of MnCl2 with the quinolone Hoxo or enrofloxacin (Herx) and the N,N'-donor heterocyclic ligand 1,10-phenanthroline (phen) results in the formation of metal complexes with the general formula [Mn(quinolonato)2(phen)]. The crystal structures of [KMn(oxo)3(MeOH)3] and [Mn(erx)2(phen)], exhibiting a 1D polymeric and a mononuclear structure, respectively, have been determined by X-ray crystallography. In these complexes, the deprotonated bidentate quinolonato ligands are coordinated to manganese(II) ion through the pyridone oxygen and a carboxylato oxygen. All complexes can act as potential antibacterial agents with [Mn(erx)2(phen)] exhibiting the most pronounced antimicrobial activity against five different microorganisms. Interaction of the complexes with calf-thymus DNA (CT DNA), studied by UV spectroscopy, has shown that they bind to CT DNA. Competitive study with ethidium bromide (EB) has shown that all complexes can displace the DNA-bound EB indicating their binding to DNA in strong competition with EB. Intercalative binding mode is proposed for the interaction of the complexes with CT DNA and has also been verified by DNA solution viscosity measurements and cyclic voltammetry. DNA electrophoretic mobility experiments suggest that [Mn(erx)2(phen)] binds strongly to supercoiled pDNA and to linearized pDNA possibly by an intercalative manner provoking double-stranded cleavage reflecting in a nuclease-like activity. The complexes exhibit good binding propensity to human or bovine serum albumin protein showing relatively high binding constant values. The binding constants of the complexes towards CT DNA and albumins have been compared to their corresponding zinc(II) and nickel(II) complexes.

  11. An in vitro analysis of the effects of various topical antimicrobial agents on methicillin-resistant and methicillin-sensitive strains of Staphylococcus aureus.

    PubMed

    Kaiser, Michael; Gil, Joel; Treu, Ryan; Valdes, Jose; Davis, Stephen

    2014-04-01

    Infections of acute and chronic wounds have a substantial negative impact on patient outcomes. Because bacterial resistance to traditional antimicrobials continues to increase, an in vitro study was conducted to examine current sensitivities of various methicillin-resistant and methicillin-sensitive strains of Staphylococcus aureus (MRSA and MSSA) to commonly used topical antimicrobial agents. Using fresh cultures of eight strains of MRSA and MSSA, the area of the zone of inhibition produced by various topical antimicrobials, including an aminoglycoside antibiotic, monocarboxylic acid antibiotic, pleuromutilin antibiotic, triple antibiotic ointment, and petrolatum ointment, was examined. Six culture plates per antimicrobial were prepared using the Kirby Bauer method; soy blood culture plates were inoculated with the bacteria, incubated for 24 hours at 37˚ C, and their zones of inhibition measured and calculated. Data were analyzed using ANOVA testing. Mupirocin treatment was the most effective antimicrobial, with areas of inhibition ranging from 30.34 cm2 to 61.70 cm2 (P <0.05), as compared to the next most effective, retapamulin, with areas of inhibition ranging from 11.97 cm2 to 23.54 cm2. This study provides current scientific data to help the development of a thoughtful rationale for the use of topical antimicrobials in wounds. Additional in vivo studies to substantiate these findings are needed.

  12. Impact of medicated feed along with clay mineral supplementation on Escherichia coli resistance to antimicrobial agents in pigs after weaning in field conditions.

    PubMed

    Jahanbakhsh, Seyedehameneh; Kabore, Kiswendsida Paul; Fravalo, Philippe; Letellier, Ann; Fairbrother, John Morris

    2015-10-01

    The aim of this study was to examine changes in antimicrobial resistance (AMR) phenotype and virulence and AMR gene profiles in Escherichia coli from pigs receiving in-feed antimicrobial medication following weaning and the effect of feed supplementation with a clay mineral, clinoptilolite, on this dynamic. Eighty E. coli strains isolated from fecal samples of pigs receiving a diet containing chlortetracycline and penicillin, with or without 2% clinoptilolite, were examined for antimicrobial resistance to 15 antimicrobial agents. Overall, an increased resistance to 10 antimicrobials was observed with time. Supplementation with clinoptilolite was associated with an early increase but later decrease in blaCMY-2, in isolates, as shown by DNA probe. Concurrently, a later increase in the frequency of blaCMY-2 and the virulence genes iucD and tsh was observed in the control pig isolates, being significantly greater than in the supplemented pigs at day 28. Our results suggest that, in the long term, supplementation with clinoptilolite could decrease the prevalence of E. coli carrying certain antimicrobial resistance and virulence genes.

  13. Efficacy of antimicrobial property of two commercially available chemomechanical caries removal agents (Carisolv and Papacarie): An ex vivo study

    PubMed Central

    Reddy, Maram Vinay Chand; Shankar, A.J. Sai; Pentakota, Venkata Girish; Kolli, Harika; Ganta, Haritha; Katari, Pavan Kumar

    2015-01-01

    Purpose: The purpose of the study is to evaluate the antimicrobial efficacy of Carisolv and Papacarie. There are only a few studies comparing the primary teeth. The objective of this study is to assess the effects of Carisolv and Papacarie on cariogenic flora and to compare them. Materials and Methods: Fifteen children aged 4–8 years who had at least two primary molars with broad occlusal cavitated lesions showing brown and softened dentin samples were selected. The selected 30 teeth were randomly divided into two groups of 15 teeth each for Carisolv and Papacarie. Dentin samples of both groups were taken prior to and following caries removal. The total viable count and lactobacilli count were determined and expressed as colony forming units per milliliter. The two methods of caries removal were then compared and the data were statistically analyzed. Results: The data of both agents (groups) were analyzed by Wilcoxon signed-rank test before and after application and showed statistical significance. Inter-comparison of data of both groups was analyzed by Mann–Whitney U test for total viable count and total Lactobacillus count which showed no statistical significance. Conclusion: Carisolv and Papacarie have similar antibacterial efficacy against cariogenic flora as chemomechanical caries removal agents. PMID:26236677

  14. Enhanced biofilm formation and increased resistance to antimicrobial agents and bacterial invasion are caused by synergistic interactions in multispecies biofilms.

    PubMed

    Burmølle, Mette; Webb, Jeremy S; Rao, Dhana; Hansen, Lars H; Sørensen, Søren J; Kjelleberg, Staffan

    2006-06-01

    Most biofilms in their natural environments are likely to consist of consortia of species that influence each other in synergistic and antagonistic manners. However, few reports specifically address interactions within multispecies biofilms. In this study, 17 epiphytic bacterial strains, isolated from the surface of the marine alga Ulva australis, were screened for synergistic interactions within biofilms when present together in different combinations. Four isolates, Microbacterium phyllosphaerae, Shewanella japonica, Dokdonia donghaensis, and Acinetobacter lwoffii, were found to interact synergistically in biofilms formed in 96-well microtiter plates: biofilm biomass was observed to increase by >167% in biofilms formed by the four strains compared to biofilms composed of single strains. When exposed to the antibacterial agent hydrogen peroxide or tetracycline, the relative activity (exposed versus nonexposed biofilms) of the four-species biofilm was markedly higher than that in any of the single-species biofilms. Moreover, in biofilms established on glass surfaces in flow cells and subjected to invasion by the antibacterial protein-producing Pseudoalteromonas tunicata, the four-species biofilms resisted invasion to a greater extent than did the biofilms formed by the single species. Replacement of each strain by its cell-free culture supernatant suggested that synergy was dependent both on species-specific physical interactions between cells and on extracellular secreted factors or less specific interactions. In summary, our data strongly indicate that synergistic effects promote biofilm biomass and resistance of the biofilm to antimicrobial agents and bacterial invasion in multispecies biofilms.

  15. Optimization of four types of antimicrobial agents to increase the inhibitory ability of marine Arthrobacter oxydans KQ11 dextranase mouthwash

    NASA Astrophysics Data System (ADS)

    Ren, Wei; Wang, Shujun; Lü, Mingsheng; Wang, Xiaobei; Fang, Yaowei; Jiao, Yuliang; Hu, Jianen

    2016-03-01

    We adopted the response surface methodology using single factor and orthogonal experiments to optimize four types of antimicrobial agents that could inhibit biofilm formation by Streptococcus mutans, which is commonly found in the human oral cavity and causes tooth decay. The objective was to improve the function of marine Arthrobacter oxydans KQ11 dextranase mouthwash (designed and developed by our laboratory). The experiment was conducted in a three-level, four-variable central composite design to determine the best combination of ZnSO4, lysozyme, citric acid and chitosan. The optimized antibacterial agents were 2.16 g/L ZnSO4, 14 g/L lysozyme, 4.5 g/L citric acid and 5 g/L chitosan. The biofilm formation inhibition reached 84.49%. In addition, microscopic observation of the biofilm was performed using scanning electron microscopy and confocal laser scanning microscopy. The optimized formula was tested in marine dextranase Arthrobacter oxydans KQ11 mouthwash and enhanced the inhibition of S. mutans. This work may be promoted for the design and development of future marine dextranase oral care products.

  16. Comparative Evaluation of Fosfomycin Activity with other Antimicrobial Agents against E.coli Isolates from Urinary Tract Infections

    PubMed Central

    Sardar, Ahmed; Navaz, Anwar; Singh, Manisha; Kabra, Vasanti

    2017-01-01

    Introduction Fosfomycin is a broad spectrum anti-microbial agent with activity against various bacterial agents. It is a bactericidal antibiotic which interferes with cell wall synthesis. Fosfomycin is rapidly absorbed orally and majority of the drug is excreted unchanged in urine with very high concentration levels achieved in urine after a single oral dose. Urine levels remain high for prolonged period which makes it a suitable drug in the treatment of Urinary Tract Infections (UTI). E.coli is the most common organism causing the UTI. With the inappropriate and inadvertent use of higher antibiotics, these bacterial isolates have acquired multidrug resistance for which treatment options are limited. Aim To evaluate the in-vitro activity of fosfomycin against uropathogenic E.coli and to compare its activity with the other anti-microbial agents. Materials and Methods This study was a prospective study done in the Department of Microbiology SVS Medical College, Mahbubnagar from Jan 2016 to Mar 2016. A total of 564 urine samples from suspected UTI cases were processed during the study period out of which 170 E.coli were isolated. Identification of the organisms were done by routine biochemical testing and antibiotic sensitivity testing was done by Kirby-Bauer disc diffusion testing according to the CLSI guidelines (M100-S23). Results A total of 170 E.coli isolates were tested for antibiotic susceptibility. Out of 170 isolates 60 (35.30%) were isolated from males and 110 (64.70%) from females with male to female ratio of 1:1.83. Majority of the isolates were obtained from the age group of 21-30 years (25.8%). Antibiotics like fosfomycin, imipenem and methenamine mandelate showed the highest sensitivity with all the isolates (100%) being susceptible to these drugs. Whereas, least sensitivity was observed for amoxyclav (15.2%) followed by cefixime (16.4%) and norfloxacin (21%). Fosfomycin has shown very good in-vitro activity against all the tested isolates when compared

  17. Anticancer and antimicrobial metallopharmaceutical agents based on palladium, gold, and silver N-heterocyclic carbene complexes.

    PubMed

    Ray, Sriparna; Mohan, Renu; Singh, Jay K; Samantaray, Manoja K; Shaikh, Mobin M; Panda, Dulal; Ghosh, Prasenjit

    2007-12-05

    Complete synthetic, structural, and biomedical studies of two Pd complexes as well as Au and Ag complexes of 1-benzyl-3-tert-butylimidazol-2-ylidene are reported. Specifically, trans-[1-benzyl-3-tert-butylimidazol-2-ylidene]Pd(pyridine)Cl2 (1a) was synthesized from the reaction of 1-benzyl-3-tert-butylimidazolium chloride (1) with PdCl2 in the presence of K2CO3 as a base. The other palladium complex, [1-benzyl-3-tert-butylimidazol-2-ylidene]2PdCl2 (1b), and a gold complex, [1-benzyl-3-tert-butylimidazol-2-ylidene]AuCl (1c), were synthesized by following a transmetallation route from the silver complex, [1-benzyl-3-tert-butylimidazol-2-ylidene]AgCl (1d), by treatment with (COD)PdCl2 and (SMe2)AuCl, respectively. The silver complex 1d in turn was synthesized by the reaction of 1 with Ag2O. The molecular structures of 1a-d have been determined by X-ray diffraction studies. Biomedical studies revealed that, while the palladium complexes 1a and 1b displayed potent anticancer activity, the gold (1c) and silver (1d) complexes exhibited significant antimicrobial properties. Specifically, 1b showed strong antiproliferative activity against three types of human tumor cells, namely, cervical cancer (HeLa), breast cancer (MCF-7), and colon adenocarcinoma (HCT 116), in culture. The antiproliferative activity of 1b was found to be considerably stronger than that of cisplatin. The 1b complex inhibited tumor cell proliferation by arresting the cell cycle progression at the G2 phase, preventing the mitotic entry of the cell. We present evidence suggesting that the treated cells underwent programmed cell death through a p53-dependent pathway. Though both the gold (1c) and silver (1d) complexes showed antimicrobial activity toward Bacillus subtilis, 1c was found to be ca. 2 times more potent than 1d.

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2007-10-17

    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

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

    PubMed Central

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

    2012-01-01

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

  1. Synthesis and characterization of novel organocobaloximes as potential catecholase and antimicrobial activity agents.

    PubMed

    Erdem-Tuncmen, Mukadder; Karipcin, Fatma; Sariboga, Bahtiyar

    2013-10-01

    An asymmetric, potentially bidentate dioxime ligand (H₂L) was formed by condensation of 4-biphenylchloroglyoxime and napthyl-1-amine. Two equivalents of H₂L were reacted with CoCl₂  · 6H₂O under appropriate conditions with deprotonation of the dioxime ligand. A series of new organocobaloxime derivatives of the type [CoR(HL)₂Py], [CoRL₂PyB₂F₄], and [CoRL₂Py(Cu(phen))₂] (H₂L = 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, ¹H 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 H₂L 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 H₂L and its complexes.

  2. Potent antimicrobial agents against azole-resistant fungi based on pyridinohydrazide and hydrazomethylpyridine structural motifs.

    PubMed

    Backes, Gregory L; Jursic, Branko S; Neumann, Donna M

    2015-07-01

    Schiff base derivatives have recently been shown to possess antimicrobial activity, and these derivatives include a limited number of salicylaldehyde hydrazones. To further explore this structure-activity relationship between salicylaldehyde hydrazones and antifungal activity, we previously synthesized and analyzed a large series of salicylaldehyde and formylpyridinetrione hydrazones for their ability to inhibit fungal growth of both azole-susceptible and azole-resistant species of Candida. While many of these analogs showed excellent growth inhibition with low mammalian cell toxicity, their activity did not extend to azole-resistant species of Candida. To further dissect the structural features necessary to inhibit azole-resistant fungal species, we synthesized a new class of modified salicylaldehyde derivatives and subsequently identified a series of modified pyridine-based hydrazones that had potent fungicidal antifungal activity against multiple Candida spp. Here we would like to present our synthetic procedures as well as the results from fungal growth inhibition assays, mammalian cell toxicity assays, time-kill assays and synergy studies of these novel pyridine-based hydrazones on both azole-susceptible and azole-resistant fungal species.

  3. The antimicrobial agents triclocarban and triclosan as potent modulators of reproduction in Potamopyrgus antipodarum (Mollusca: Hydrobiidae).

    PubMed

    Geiß, Cornelia; Ruppert, Katharina; Heidelbach, Tanja; Oehlmann, Jörg

    2016-11-09

    In this study, we assessed the chronic effects of the two antimicrobial substances triclocarban (TCC) and triclosan (TCS) on reproduction of a mollusk species by using the reproduction test with the New Zealand mudsnail Potamopyrgus antipodarum. Snails coming from a laboratory culture were exposed for 28 days to nominal concentrations ranging from 0.1 up to 10 µg/L for both chemicals (measured 0.082-8.85 µg TCC/L; 0.068-6.26 µg TCS/L). At the end of the experiment, snails were dissected and embryos in the brood pouch were counted to assess the individualized reproductive success of adult snails. Exposure to TCC resulted in an inverted u-shaped concentration-response relationship, with a stimulation of reproduction at low concentrations followed by an inhibition at higher concentrations. The no observed effect concentration (NOEC) and the lowest observed effect concentration (LOEC) were 0.082 and 0.287 µg/L, respectively. TCS caused significantly increased embryo numbers at all tested concentrations, except in the group of 0.170 µg/L. Therefore, the NOEC for TCS was 0.170 µg/L and the LOEC was 0.660 µg/L. These results indicate that TCC and TCS may cause reproductive effects at environmentally relevant concentrations indicating a potential risk for aquatic organisms in the environment.

  4. In-house validation of PremiTest, a microbiological screening test with solvent extraction, for the detection of antimicrobial residues in poultry muscles.

    PubMed

    Magalhães, C G; De Paiva, C R; Botelho, B G; De Oliveira, A M G; De Souza, L F; Nonaka, C V; Santos, K V; Farias, L M; Carvalho, M A R

    2012-01-01

    PremiTest, a microbial inhibition test for the screening of antimicrobial residues, was validated according to the criteria established by Decision 2002/657/EC. Sensitivity, detection capability (CCβ), specificity, selectivity, robustness and applicability were evaluated. The methodology involves the technique of solvent extraction, which increases the detection capability of the test for a wider range of antibiotics. The following CCβ values in poultry muscle were found: penicillin G ≤ 12.5 µg kg(-1), total sulfonamides ≤ 75 µg kg(-1), erythromycin 75 µg kg(-1) and lincomycin 50 µg kg(-1). The detection capability of chlortetracycline was equal to its maximum residue limit (100 µg kg(-1)) and the method did not detect gentamicin (1000 µg kg(-1)), for which no MRL is established in poultry muscle. Specificity evaluated in relation to different analytes and matrices did not detect any interferences in the tests results; whilst the robustness showed that the pH neutralisation point of the extract affects the analytical results and the kits' performance. Only the screening of tetracyclines requires the analysis of extracts without pH neutralisation. The results of the validation process showed that this method is acceptable for screening β-lactam, sulfonamide and macrolide antimicrobial groups in the National Residues and Contaminants Control Programme (PNCRC), and that for this it is fit for purpose.

  5. [Susceptibilities of Escherichia coli, Salmonella and Staphylococcus aureus isolated from animals to ofloxacin and commonly used antimicrobial agents].

    PubMed

    Takahashi, I; Yoshida, T; Higashide, Y; Sakano, T

    1990-01-01

    Susceptibilities of Escherichia coli, Salmonella and Staphylococcus aureus isolated from chickens, pigs and cattle to ofloxacin (OFLX) and commonly used antimicrobial agents were investigated. 1. E. coli (28 isolates) demonstrated the highest level of susceptibility of OFLX (MIC 0.10-0.39 micrograms/ml for all the isolates) among all the test drugs. Commonly used antimicrobial agents to which these isolates responded with relatively high susceptibilities (MIC50 0.78-6.25 micrograms/ml) included oxolinic acid (OXA), ampicillin (ABPC), kanamycin (KM) and chloramphenicol (CP) with their MIC50 values in the increasing order as above. Drugs to which these isolates responded with moderate to weak susceptibilities (MIC50 25 approximately greater than 800 micrograms/ml) were doxycycline (DOXY), streptomycin (SM), spectinomycin (SPCM) and sulfadimethoxine (SDMX) in the increasing order of MIC50. E. coli isolates with resistances to all the test drugs other than OFLX and OXA amounted to 7.1-57.1% of the isolates examined and 20 isolates (71.4%) in total. 2. Susceptibilities to OFLX and 4 existing pyridonecarboxylic acid derivatives of E. coli (48 samples) isolated recently from diarrheal pigs were compared. When evaluated in terms of MIC50, the values of OFLX and norfloxacin were both 0.10 micrograms/ml. The values increased by differences of 0.39-3.13 micrograms/ml in an order of OXA, pipemidic acid and nalidixic acid. 3. Salmonella (28 isolates) demonstrated the highest level of susceptibility to OFLX (MIC 0.20-0.39 micrograms/ml for all the isolates) among all the test drugs. The drugs to which these isolates responded with relatively high to moderate susceptibilities (MIC50 0.78-12.5 micrograms/ml) included ABPC, OXA, DOXY, KM, CP and SM with their MIC50 values increasing in this order. The drugs to which the isolates responded with low susceptibilities (MIC50 above 100 micrograms/ml) were SPCM and SDMX. Of all the 28 Salmonella isolates tested, 7.1-32.1% were resistant

  6. [Susceptibility of clinically-isolated bacteria strains to respiratory quinolones and evaluation of antimicrobial agent efficacy by Monte Carlo simulation].

    PubMed

    Kosaka, Tadashi; Yamada, Yukiji; Kimura, Takeshi; Kodama, Mai; Fujitomo, Yumiko; Masaki, Nakanishi; Toshiaki, Komori; Keisuke, Shikata; Fujita, Naohisa

    2016-02-01

    Respiratory quinolones (RQs) are broad-spectrum antimicrobial agents used for the treatment of a wide variety of community-acquired and nosocomial infections. However, bacterial resistance to quinolones has been on the increase. In this study, we investigated the predicted efficacy of RQs for various strains of 9 bacterial species clinically isolated at our university hospital using the Monte Carlo simulation (MCS) method based on pharmacokinetics/pharmacodynamics modeling. In addition, the influence of the patients' renal function on the efficacy of RQs was evaluated. We surveyed antimicrobial susceptibility testing of 9 bacterial species (n = number of strains) [Streptococcus pneumoniae (n = 15), Streptococcus pyogenes (n = 14), Streptococcus agalactiae (n = 19), methicillin-susceptible Staphylococcus aureus (MSSA) (n = 24), Escherichia coli (n = 35), Haemophilus influenzae (n = 17), Klebsiella pneumoniae (n = 14), Pseudomonas aeruginosa (n = 31), and Moraxella catarrhalis (n = 11)] to 4 RQs [garenoxacin (GRNX), levofloxacin (LVFX), sitafloxacin (STFX), and moxifloxacin (MFLX)]. We found that compared with the other RQs, Gram-positive cocci was most resistant to LVFX, and that the minimum inhibitory concentration (MIC₉₀) values for S. pneumoniae, S. pyogenes, S. agalactiae, and MSSA were high (2, 16, > 16, and 8 µg/mL, respectively). In regard to Gram-negative rods, the susceptibility of E. coli to RQs was found to be decreased, with the MIC₉₀ values of GRNX, LVFX, STFX, and MFLX being > 16, 16, 1, and 16 µg/mL, respectively. MCS revealed that the target attainment rate of the area under the unbound concentration-time curve divided by the MIC₉₀ (ƒ · AUC/MIC ratio), against S. pneumoniae was 86.9-100%, but against E. coli was low (52.1-66.2%). The ƒ · AUC/MIC target attainment rate of LVFX against S. pneumoniae, S. pyogenes, and S. agalactiae tended to decrease due to increased creatinine clearance, and that of LVFX and STFX against MSSA also

  7. In Silico Studies Most Employed in the Discovery of New Antimicrobial Agents.

    PubMed

    Tamay-Cach, F; Villa-Tanaca, M L; Trujillo-Ferrara, J G; Alemán-González-Duhart, D; Quintana-Pérez, J C; González-Ramírez, I A; Correa-Basurto, J

    2016-01-01

    The present review summarizes the methods most used in drug search and design, which may help to keep pace with the growing antibiotic resistance among pathogens. The rate of reduction in the effectiveness of many antimicrobial medications, caused by this resistance, is faster than new drug development, thereby creating a worldwide public health threat. Among the scientific community, the urgency of finding new drugs is peaking interest in the use of in silico studies to explore the interaction of compounds with target receptors. With this approach, small molecules (designed or retrieved from data bases) are tested with computer-aided molecular simulation to explore their efficacy. That is, ligand-protein complexes are constructed and evaluated via virtual screening (VS), molecular dynamics (MD), and docking simulations with the data from the physical, chemical and pharmacological properties of such molecules. Additionally, the application of quantitative structure-activity relationship (QSAR), multi-target quantitative structure-activity relationship (mt- QSAR), and multi-tasking quantitative structure-biological effect (mtk-QSBER) can be enhanced by principal component analysis and systematic workflows. These types of studies aid in selecting a group of promising molecules with high potency and selectivity as well as low toxicity, thus making in vitro and in vivo (animal model) testing more efficient. Since knowledge of the receptor topography and receptor-ligand interactions has yielded promising compounds and effective drugs, there is now no doubt that the use of in silico tools can lead to more rapid validation of new potential drugs for preclinical studies and clinical trials.

  8. Essential oil from black currant buds as chemotaxonomy marker and antimicrobial agent.

    PubMed

    Ethorđević, Boban S; Pljevljakušić, Ðorđević S; Savikin, Katarina P; Stević, Tatjana R; Bigović, Dubravka J

    2014-08-01

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

  9. Development of potent anti-infective agents from Silurana tropicalis: conformational analysis of the amphipathic, alpha-helical antimicrobial peptide XT-7 and its non-haemolytic analogue [G4K]XT-7.

    PubMed

    Subasinghage, Anusha P; Conlon, J Michael; Hewage, Chandralal M

    2010-04-01

    Peptide XT-7 (GLLGP(5)LLKIA(10)AKVGS(15)NLL.NH(2)) is a cationic, leucine-rich peptide, first isolated from skin secretions of the frog, Silurana tropicalis (Pipidae). The peptide shows potent, broad-spectrum antimicrobial activity but its therapeutic potential is limited by haemolytic activity (LC(50)=140 microM). The analogue [G4K]XT-7, however, retains potent antimicrobial activity but is non-haemolytic (LC(50)>500 microM). In order to elucidate the molecular basis for this difference in properties, the three dimensional structures of XT-7 and the analogue have been investigated by proton NMR spectroscopy and molecular modelling. In aqueous solution, both peptides lack secondary structure. In a 2,2,2-trifluoroethanol (TFE-d(3))-H(2)O mixed solvent system, XT-7 is characterised by a right handed alpha-helical conformation between residues Leu(3) and Leu(17) whereas [G4K]XT-7 adopts a more restricted alpha-helical conformation between residues Leu(6) and Leu(17). A similar conformation for XT-7 in 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) micellular media was observed with a helical segment between Leu(3) and Leu(17). However, differences in side chain orientations restricting the hydrophilic residues to a smaller patch resulted in an increased hydrophobic surface relative to the conformation in TFE-H(2)O. Molecular modelling of the structures obtained in our study demonstrates the amphipathic character of the helical segments. It is proposed that the marked decrease in haemolytic activity produced by the substitution Gly(4)-->Lys in XT-7 arises from a decrease in both helicity and hydrophobicity. These studies may facilitate the development of potent but non-toxic anti-infective agents based upon the structure of XT-7.

  10. Susceptibilities of Listeria species isolated from food to nine antimicrobial agents.

    PubMed Central

    Franco Abuín, C M; Quinto Fernández, E J; Fente Sampayo, C; Rodríguez Otero, J L; Domínguez Rodríguez, L; Cepeda Sáez, A

    1994-01-01

    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. PMID:7979303

  11. Antimicrobials, mucosal coating agents, anesthetics, analgesics, and nutritional supplements for alimentary tract mucositis.

    PubMed

    Barasch, Andrei; Elad, Sharon; Altman, Arnold; Damato, Kathryn; Epstein, Joel

    2006-06-01

    This review focuses on the value of several groups of agents for the prevention and treatment of mucositis. The review refers to alimentary mucositis as a generalized term that includes oral mucositis and gastrointestinal mucositis. This paper is part of the systematic review made by the mucositis study group which operates in the Multinational Association of Supportive Care in Cancer (MASCC)/International Society of Oral Oncology (ISOO). Several new guidelines are suggested in this review as an update to the primary systematic review that was published by the same group in 2004.

  12. Food Antimicrobials Nanocarriers

    PubMed Central

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

    2014-01-01

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

  13. Platismatia glaucia and Pseudevernia furfuracea lichens as sources of antioxidant, antimicrobial and antibiofilm agents.

    PubMed

    Mitrovic, Tatjana; Stamenkovic, Slaviša; Cvetkovic, Vladimir; Radulovic, Niko; Mladenovic, Marko; Stankovic, Milan; Topuzovic, Marina; Radojevic, Ivana; Stefanovic, Olgica; Vasic, Sava; Comic, Ljiljana

    2014-01-01

    The antioxidative, antimicrobial and antibiofilm potentials of acetone, ethyl acetate and methanol extracts of lichen species Platismatia glauca and Pseudevernia furfuracea were evaluated. The phytochemical analysis by GC, GC/MS and NMR revealed caperatic acid, atraric acid, atranorin and chloroatranorin as the predominant compounds in Platismatia glauca. Atraric acid, olivetoric acid, atranorin and chloroatranorin were the major constituents in Pseudevernia furfuracea. The strong antioxidant capacities of the Platismatia glauca and Pseudevernia furfuracea extracts were assessed by their total phenolic and flavonoid contents and DPPH scavenging activities. The methanol extracts of both species exhibited the strongest antioxidant activities with the highest IC50 value for Pseudevernia furfuracea (95.33 µg/mL). The lichen extracts demonstrated important antibacterial activities against 11 bacterial strains with detectable MIC values from 0.08 mg/mL to 2.5 mg/mL for Platismatia glauca and from 0.005 mg/mL to 2.5 mg/mL for Pseudevernia furfuracea. While the antibacterial activities of Pseudevernia furfuracea were solvent-independent, the acetone and ethyl acetate extracts of Platismatia glauca showed higher antibacterial activities compared to its methanol extract. The methanol extracts of both species demonstrated significant antifungal activities against 9 fungal strains with detectable MIC values from 0.04 mg/mL to 2.5 mg/mL. The best antifungal activities were determined against Candida species in Pseudevernia furfuracea extracts with remarkable MIC values which were lower than the MIC values of the positive contol fluconazole. The acetone and ethyl acetate extracts of Platismatia glauca showed better antibiofilm activities on Staphylococcus aureus and Proteus mirabilis with BIC value at 0.63 mg/mL then its methanol extract. On the other hand, the methanol extract of Pseudevernia furfuracea was more potent with BIC value at 1.25 mg/mL on Staphylococcus aureus and

  14. Platismatia glaucia and Pseudevernia furfuracea lichens as sources of antioxidant, antimicrobial and antibiofilm agents

    PubMed Central

    Mitrovic, Tatjana; Stamenkovic, Slaviša; Cvetkovic, Vladimir; Radulovic, Niko; Mladenovic, Marko; Stankovic, Milan; Topuzovic, Marina; Radojevic, Ivana; Stefanovic, Olgica; Vasic, Sava; Comic, Ljiljana

    2014-01-01

    The antioxidative, antimicrobial and antibiofilm potentials of acetone, ethyl acetate and methanol extracts of lichen species Platismatia glauca and Pseudevernia furfuracea were evaluated. The phytochemical analysis by GC, GC/MS and NMR revealed caperatic acid, atraric acid, atranorin and chloroatranorin as the predominant compounds in Platismatia glauca. Atraric acid, olivetoric acid, atranorin and chloroatranorin were the major constituents in Pseudevernia furfuracea. The strong antioxidant capacities of the Platismatia glauca and Pseudevernia furfuracea extracts were assessed by their total phenolic and flavonoid contents and DPPH scavenging activities. The methanol extracts of both species exhibited the strongest antioxidant activities with the highest IC50 value for Pseudevernia furfuracea (95.33 µg/mL). The lichen extracts demonstrated important antibacterial activities against 11 bacterial strains with detectable MIC values from 0.08 mg/mL to 2.5 mg/mL for Platismatia glauca and from 0.005 mg/mL to 2.5 mg/mL for Pseudevernia furfuracea. While the antibacterial activities of Pseudevernia furfuracea were solvent–independent, the acetone and ethyl acetate extracts of Platismatia glauca showed higher antibacterial activities compared to its methanol extract. The methanol extracts of both species demonstrated significant antifungal activities against 9 fungal strains with detectable MIC values from 0.04 mg/mL to 2.5 mg/mL. The best antifungal activities were determined against Candida species in Pseudevernia furfuracea extracts with remarkable MIC values which were lower than the MIC values of the positive contol fluconazole. The acetone and ethyl acetate extracts of Platismatia glauca showed better antibiofilm activities on Staphylococcus aureus and Proteus mirabilis with BIC value at 0.63 mg/mL then its methanol extract. On the other hand, the methanol extract of Pseudevernia furfuracea was more potent with BIC value at 1.25 mg/mL on Staphylococcus aureus

  15. Development and Sequential Analysis of a New Multi-Agent, Anti-Acne Formulation Based on Plant-Derived Antimicrobial and Anti-Inflammatory Compounds

    PubMed Central

    Saviuc, Crina; Ciubucă, Bianca; Dincă, Gabriela; Bleotu, Coralia; Drumea, Veronica; Chifiriuc, Mariana-Carmen; Popa, Marcela; Gradisteanu Pircalabioru, Gratiela; Marutescu, Luminita; Lazăr, Veronica

    2017-01-01

    The antibacterial and anti-inflammatory potential of natural, plant-derived compounds has been reported in many studies. Emerging evidence indicates that plant-derived essential oils and/or their major compounds may represent a plausible alternative treatment for acne, a prevalent skin disorder in both adolescent and adult populations. Therefore, the purpose of this study was to develop and subsequently analyze the antimicrobial activity of a new multi-agent, synergic formulation based on plant-derived antimicrobial compounds (i.e., eugenol, β-pinene, eucalyptol, and limonene) and anti-inflammatory agents for potential use in the topical treatment of acne and other skin infections. The optimal antimicrobial combinations selected in this study were eugenol/β-pinene/salicylic acid and eugenol/β-pinene/2-phenoxyethanol/potassium sorbate. The possible mechanisms of action revealed by flow cytometry were cellular permeabilization and inhibition of efflux pumps activity induced by concentrations corresponding to sub-minimal inhibitory (sub-MIC) values. The most active antimicrobial combination represented by salycilic acid/eugenol/β-pinene/2-phenoxyethanol/potassium sorbate was included in a cream base, which demonstrated thermodynamic stability and optimum microbiological characteristics. PMID:28106736

  16. Development and Sequential Analysis of a New Multi-Agent, Anti-Acne Formulation Based on Plant-Derived Antimicrobial and Anti-Inflammatory Compounds.

    PubMed

    Saviuc, Crina; Ciubucă, Bianca; Dincă, Gabriela; Bleotu, Coralia; Drumea, Veronica; Chifiriuc, Mariana-Carmen; Popa, Marcela; Gradisteanu Pircalabioru, Gratiela; Marutescu, Luminita; Lazăr, Veronica

    2017-01-17

    The antibacterial and anti-inflammatory potential of natural, plant-derived compounds has been reported in many studies. Emerging evidence indicates that plant-derived essential oils and/or their major compounds may represent a plausible alternative treatment for acne, a prevalent skin disorder in both adolescent and adult populations. Therefore, the purpose of this study was to develop and subsequently analyze the antimicrobial activity of a new multi-agent, synergic formulation based on plant-derived antimicrobial compounds (i.e., eugenol, β-pinene, eucalyptol, and limonene) and anti-inflammatory agents for potential use in the topical treatment of acne and other skin infections. The optimal antimicrobial combinations selected in this study were eugenol/β-pinene/salicylic acid and eugenol/β-pinene/2-phenoxyethanol/potassium sorbate. The possible mechanisms of action revealed by flow cytometry were cellular permeabilization and inhibition of efflux pumps activity induced by concentrations corresponding to sub-minimal inhibitory (sub-MIC) values. The most active antimicrobial combination represented by salycilic acid/eugenol/β-pinene/2-phenoxyethanol/potassium sorbate was included in a cream base, which demonstrated thermodynamic stability and optimum microbiological characteristics.

  17. The effect of colouring agent on the physical properties of glass ceramic produced from waste glass for antimicrobial coating deposition

    NASA Astrophysics Data System (ADS)

    Juoi, J. M.; Ayoob, N. F.; Rosli, Z. M.; Rosli, N. R.; Husain, K.

    2016-07-01

    Domestic waste glass is utilized as raw material for the production of glass ceramic material (GCM) via sinter crystallisation route. The glass ceramic material in a form of tiles is to be utilized for the deposition of Ag-TiO2 antimicrobial coating. Two types of soda lime glass (SLG) that are non-coloured and green SLG are utilised as main raw materials during the batch formulation in order to study the effect of colouring agent (Fe2O3) on the physical and mechanical properties of glass ceramic produced. Glass powder were prepared by crushing bottles using hammer milled with milling machine and sieved until they passed through 75 µm sieve. The process continues by mixing glass powder with ball clay with ratio of 95:5 wt. %, 90:10 wt. % and 85:15 wt. %. Each batch mixture was then uniaxial pressed and sintered at 800°C, 825 °C and 850 °C. The physical and mechanical properties were then determined and compared between those produced from non-coloured and green coloured SLG in order to evaluate the effect of colouring agent (Fe2O3) on the GCM produced. The optimum properties of non-coloured SLG is produced with smaller ball clay content (10 wt. %) compared to green SLG (15 wt. %). The physical properties (determined thru ASTM C373) of the optimized GCM produced from non-coloured SLG and green SLG are 0.69 % of porosity, 1.92 g/cm3 of bulk density, 0.36 % of water absorption; and 1.96 % of porosity, 2.69 g/cm3 of bulk density, 0.73 % of water absorption; respectively. Results also indicate that the most suitable temperature in producing GCM from both glasses with optimized physical and mechanical properties is at 850 °C.

  18. Gold Nanoparticles: An Efficient Antimicrobial Agent against Enteric Bacterial Human Pathogen

    PubMed Central

    Shamaila, Shahzadi; Zafar, Noshin; Riaz, Saira; Sharif, Rehana; Nazir, Jawad; Naseem, Shahzad

    2016-01-01

    Enteric bacterial human pathogens, i.e., Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Klebsiella pneumoniae, are the major cause of diarrheal infections in children and adults. Their structure badly affects the human immune system. It is important to explore new antibacterial agents instead of antibiotics for treatment. This project is an attempt to explain how gold nanoparticles affect these bacteria. We investigated the important role of the mean particle size, and the inhibition of a bacterium is dose-dependent. Ultra Violet (UV)-visible spectroscopy revealed the size of chemically synthesized gold nanoparticle as 6–40 nm. Atomic force microscopy (AFM) analysis confirmed the size and X-ray diffractometry (XRD) analysis determined the polycrystalline nature of gold nanoparticles. The present findings explained how gold nanoparticles lyse Gram-negative and Gram-positive bacteria. PMID:28335198

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

    PubMed

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

    2014-08-18

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

  20. Susceptibility to antimicrobial agents among bovine mastitis pathogens isolated from North American dairy cattle, 2002-2010.

    PubMed

    Lindeman, Cynthia J; Portis, Ellen; Johansen, Lacie; Mullins, Lisa M; Stoltman, Gillian A

    2013-09-01

    Approximately 8,000 isolates of Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis, Staphylococcus aureus, and Escherichia coli, isolated by 25 veterinary laboratories across North America between 2002 and 2010, were tested for in vitro susceptibility to beta-lactam, macrolide, and lincosamide drugs. The minimal inhibitory concentrations (MICs) of the beta-lactam drugs remained low against most of the Gram-positive strains tested, and no substantial changes in the MIC distributions were seen over time. Of the beta-lactam antimicrobial agents tested, only ceftiofur showed good in vitro activity against E. coli. The MICs of the macrolides and lincosamides also remained low against Gram-positive mastitis pathogens. While the MIC values given by 50% of isolates (MIC50) for erythromycin and pirlimycin and the streptococci were all low (≤0.5 µg/ml), the MIC values given by 90% of isolates (MIC90) were higher and more variable, but with no apparent increase over time. Staphylococcus aureus showed little change in erythromycin susceptibility over time, but there may be a small, numerical increase in pirlimycin MIC50 and MIC90 values. Overall, the results suggest that mastitis pathogens in the United States and Canada have not shown any substantial changes in the in vitro susceptibility to beta-lactam, macrolide, and lincosamide drugs tested over the 9 years of the study.

  1. Comparative in vitro synergistic activity of new beta-lactam antimicrobial agents and amikacin against Pseudomonas aeruginosa and Serratia marcescens.

    PubMed Central

    Kurtz, T O; Winston, D J; Bruckner, D A; Martin, W J

    1981-01-01

    The in vitro synergistic activities of moxalactam, cefoperazone, or cefotaxime in combination with amikacin or piperacillin were compared against aminoglycoside-susceptible and aminoglycoside-resistant isolates of Pseudomonas aeruginosa and Serratia marcescens by the checkerboard agar dilution method. All antimicrobial combinations demonstrated some synergy, and no antagonism was observed. Moxalactam plus amikacin and piperacillin plus amikacin were most frequently synergistic (two-thirds of the isolates inhibited synergistically by each combination), whereas combinations of moxalactam, cefotaxime, or cefoperazone with piperacillin were synergistic against only 18 to 25% of the isolates. Moxalactam plus amikacin was the combination most often synergistic for amikacin-susceptible P. aeruginosa, and piperacillin plus amikacin was the combination most frequently synergistic for amikacin-resistant P. aeruginosa and amikacin-susceptible S. marcescens. These results demonstrate frequent in vitro synergistic activity between the new beta-lactam agents and amikacin (especially moxalactam or piperacillin with amikacin), but comparative clinical trials are needed to establish the relative efficacy and toxicity of these combinations. PMID:6792982

  2. Hantzsch reaction: synthesis and characterization of some new 1,4-dihydropyridine derivatives as potent antimicrobial and antioxidant agents.

    PubMed

    Vijesh, A M; Isloor, Arun M; Peethambar, S K; Shivananda, K N; Arulmoli, T; Isloor, Nishitha A

    2011-11-01

    In the present study two new series of Hantzsch 1,4-dihydropyridine derivatives (1,4-DHPs) containing substituted pyrazole moiety (4a-f and 5a-f) were synthesized by the reaction of 3-aryl-1H-pyrazole-4-carbaldehydes with 1,3-dicarbonylcompounds (ethylacetoacetate and methylacetoacetate) and ammonium acetate. The newly synthesized compounds were characterized by IR, NMR, mass spectral study and also by C, H, N analyses. New compounds were screened for their antimicrobial activity by well plate method (zone of inhibition). Antioxidant studies of the synthesized compounds were also performed by measuring the DPPH radical scavenging assay. Compounds 4c, 4e and 4f were found to be potent antibacterial and antioxidant agents. The acute oral toxicity study for the compounds 4c, 4e and 4f were carried out and the experimental studies revealed that compounds 4c and 4e is safe up to 3000 mg/kg and no death of animals were recorded. However in compound 4f, we found mortality above 2000 mg and also significant behavioral changes in experimental animals.

  3. Potato (Solanum tuberosum L. cv. Gogu valley) protein as a novel antimicrobial agent in weanling pigs.

    PubMed

    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

    2008-07-01

    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.

  4. In vitro study of the antimicrobial effects of radiological contrast agents used in arthrography.

    PubMed

    Bruins, M J; Zwiers, J H; Verheyen, C C P M; Wolfhagen, M J H M

    2011-01-01

    Aspiration arthrography using an iodinated contrast medium is a useful tool for the investigation of septic or aseptic loosening of arthroplasties and of septic arthritis. Previously, the contrast media have been thought to cause false negative results in cultures when present in aspirated samples of synovial fluid, probably because free iodine is bactericidal, but reports have been inconclusive. We examined the influence of the older, high osmolar contrast agents and the low osmolar media used currently on the growth of ten different micro-organisms capable of causing deep infection around a prosthesis. Five media were tested, using a disc diffusion technique and a time-killing curve method in which high and low inocula of micro-organisms were incubated in undiluted media. The only bactericidal effects were found with low inocula of Escherichia coli and Pseudomonas aeruginosa in ioxithalamate, one of the older ionic media. The low and iso-osmolar iodinated contrast media used currently do not impede culture. Future study must assess other causes of false negative cultures of synovial fluid and new developments in enhancing microbial recovery from aspirated samples.

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

    PubMed Central

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

    2014-01-01

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

  6. Investigating the effectiveness of St John's wort herb as an antimicrobial agent against mycobacteria.

    PubMed

    Mortensen, Trent; Shen, Shujie; Shen, Fenann; Walsh, Marie K; Sims, Ronald C; Miller, Charles D

    2012-09-01

    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.

  7. Minimum inhibitory concentrations of selected antimicrobial agents for Moraxella bovoculi associated with infectious bovine keratoconjunctivitis.

    PubMed

    Angelos, John A; Ball, Louise M; Byrne, Barbara A

    2011-05-01

    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.

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

    PubMed

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

    2014-10-15

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

  9. Susceptibility of clinical isolates of Campylobacter pylori to 24 antimicrobial and anti-ulcer agents.

    PubMed

    Glupczynski, Y; Delmee, M; Bruck, C; Labbe, M; Avesani, V; Burette, A

    1988-06-01

    Forty-nine isolates of Campylobacter pylori were tested for their susceptibility to twenty antibiotics and four anti-ulcer agents by an agar dilution technique. Penicillin and amoxycillin were the most active drugs (MIC90, 0.06 microgram/ml); erythromycin, cefazolin, minocycline, ciprofloxacin, ofloxacin and gentamicin were slightly less active (MIC90, less than or equal to 1 microgram/ml). Moderate activity was found for doxycyclin, rifampin, nitrofurantoin, norfloxacin, pefloxacin, enoxacin, paromomycin, metronidazole and tinidazole. All strains were resistant to trimethoprim (MIC greater than 512 micrograms/ml). Nalidixic acid (MIC90, greater than 256 micrograms/ml) and colistin (MIC90, greater than 64 micrograms/ml) had little to no activity. Of four anti-ulcer drugs, only bismuth subcitrate showed activity (MIC90, 64 micrograms/ml). Strains resistant to all 4-quinolones were found in patients who had previously received ofloxacin as part of a clinical trial aimed at eradication of C. pylori. These isolates remained susceptible to amoxycillin, tetracyclines and to other classes of antibiotics.

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

    NASA Astrophysics Data System (ADS)

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

    2012-01-01

    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 γ-radiation on plant extracts. The aim of this work was to evaluate the effect of ionizing radiation (0, 5, 10, 15, 20, 25 and 35 kGy) on extracts prepared from in vitro plants of Q. saponaria to be used as antimicrobial agent in irradiated edible coating based on calcium caseinate and whey protein isolated, and also to establish the concentration of Q. saponaria extract to be added as an antifungal agent in the coating. Gamma irradiation since 15 kGy affects negatively the antimicrobial activity and metabolites composition of extract of Q. saponaria by reducing compounds of phenolic nature. Otherwise no effect on saponins profile was observed even at higher doses. It was possible to conclude that the antifungal activity of Q. saponaria extract is mainly related to phenolic compounds content. In addition, our work also shows that to obtain an efficient antifungal protection is necessary to add a minimum concentration of 6% of the extract after the coating irradiation.

  11. Comparative study of three screening tests, two microbiological tube tests, and a multi-sulphonamide ELISA kit for the detection of antimicrobial and sulphonamide residues in eggs.

    PubMed

    Gaudin, V; Hedou, C; Rault, A; Sanders, P; Verdon, E

    2009-04-01

    The screening of antimicrobial residues in eggs is an especially important subject. Three different commercial kits for the screening of sulphonamides and other antimicrobials in eggs were validated in accordance with Decision 2002/657/EC: one enzyme-linked immunoabsorbant assay (ELISA) kit multi-sulphonamides (from RAISIO Diagnostics) and two microbiological tests (a Premi test from DSM and an Explorer kit from Zeu-Inmunotec). The false-positive rates were lower than 2% for all kits. The detection capabilities (CCbeta) have to be as low as possible for banned substances and lower than the maximum residue limit (MRL) when MRLs have been set. The sensitivity of the Premi test was better than that of the Explorer test, probably because of the dilution of the eggs before the Explorer test was used. The CCbeta values towards most of the tested sulphonamides were satisfactory with the Premi test (< or = 100 microg kg(-1)). Performance in a proficiency test for the detection of sulphonamides in eggs with the Premi test confirmed these results. The detection capabilities of tetracycline and doxycycline were at the level of the MRL or twice the MRL maximum. The detection capabilities for chlortetracycline and oxytetracycline were higher (four to six times the MRL). The detection capabilities for amoxicillin, neomycin, tylosin and erythromycin were lower than their respective MRLs. Detection capabilities for sulphonamides were much lower for the ELISA kit than for microbiological tests. The ELISA kit could be recommended for the targeted screening of sulphonamides in eggs. On the other hand, the Explorer and Premi tests could be used as wide screening tests allowing the detection of most of the antimicrobial families.

  12. cgMolluscidin, a novel dibasic residue repeat rich antimicrobial peptide, purified from the gill of the Pacific oyster, Crassostrea gigas.

    PubMed

    Seo, Jung-Kil; Lee, Min Jeong; Nam, Bo-Hye; Park, Nam Gyu

    2013-08-01

    A 5.5 kDa antimicrobial peptide consisting of 55 amino acids, cgMolluscidin, was purified from the acidified gill extract of the Pacific oyster, Crassostrea gigas, by ion-exchange and C18 reversed-phase high performance liquid chromatography. By comparing the N-terminal amino acid sequences and the molecular weight of this peptide with those of other known antimicrobial peptides, it has been revealed that this peptide had no homology with any known peptides. cgMolluscidin showed potent antimicrobial activity against both Gram-positive bacteria, including Bacillus subtilis, Micrococcus luteus, and Staphylococcus aureus (minimal effective concentrations [MECs]; 1.3-31.3 μg/mL), and Gram-negative bacteria, including Escherichia coli, Salmonella enterica, and Vibrio parahaemolyticus ([MECs]; 0.4-2.3 μg/mL), without hemolytic activity. However, cgMolluscidin did not show any significant activity against Candida albicans. The deduced amino acid sequence of the cgMolluscidin showed no hit in public protein databases, while the nucleotide sequence had a 99% homology (E value = 0) with only the unknown ESTs sequenced by C. gigas EST project. Tissue distribution of the cgMolluscidin mRNA suggests that it is constitutively expressed as a mature form in a non-tissue-specific manner. The cgMolluscidin mRNA expression level was significantly up-regulated at 12 h (2.8-fold) post injection with Vibrio sp. This peptide is highly basic and contains several dibasic residue repeats including Lysine-Lysine or Lysine-Arginine in the sequence, but may not form an ordered structure. These results suggest that cgMolluscidin might be an oyster-specific novel antimicrobial peptide.

  13. USING REDUCING AGENTS TO ELIMINATE CHLORINE DIOXIDE AND CHLORITE ION RESIDUALS IN DRINKING WATER

    EPA Science Inventory

    In an effort to determine the viability of various disinfection alternatives, the Evansville, Ind. Water and Sewer Utility is engaged in a pilot-plant investigation to compare chlorine dioxide and ozone pretreatment. As a result of increased speculation that the total residual c...

  14. Bacteriophage PBC1 and its endolysin as an antimicrobial agent against Bacillus cereus.

    PubMed

    Kong, Minsuk; Ryu, Sangryeol

    2015-04-01

    Bacillus cereus is an opportunistic human pathogen responsible for food poisoning and other, nongastrointestinal infections. Due to the emergence of multidrug-resistant B. cereus strains, the demand for alternative therapeutic options is increasing. To address these problems, we isolated and characterized a Siphoviridae virulent phage, PBC1, and its lytic enzymes. PBC1 showed a very narrow host range, infecting only 1 of 22 B. cereus strains. Phylogenetic analysis based on the major capsid protein revealed that PBC1 is more closely related to the Bacillus clarkii phage BCJA1c and phages of lactic acid bacteria than to the phages infecting B. cereus. Whole-genome comparison showed that the late-gene region, including the terminase gene, structural genes, and holin gene of PBC1, is similar to that from B. cereus temperate phage 250, whereas their endolysins are different. Compared to the extreme host specificity of PBC1, its endolysin, LysPBC1, showed a much broader lytic spectrum, albeit limited to the genus Bacillus. The catalytic domain of LysPBC1 when expressed alone also showed Bacillus-specific lytic activity, which was lower against the B. cereus group but higher against the Bacillus subtilis group than the full-length protein. Taken together, these results suggest that the virulent phage PBC1 is a useful component of a phage cocktail to control B. cereus, even with its exceptionally narrow host range, as it can kill a strain of B. cereus that is not killed by other phages, and that LysPBC1 is an alternative biocontrol agent against B. cereus.

  15. The human milk protein-lipid complex HAMLET sensitizes bacterial pathogens to traditional antimicrobial agents.

    PubMed

    Marks, Laura R; Clementi, Emily A; Hakansson, Anders P

    2012-01-01

    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

  16. Bacteriophage PBC1 and Its Endolysin as an Antimicrobial Agent against Bacillus cereus

    PubMed Central

    Kong, Minsuk

    2015-01-01

    Bacillus cereus is an opportunistic human pathogen responsible for food poisoning and other, nongastrointestinal infections. Due to the emergence of multidrug-resistant B. cereus strains, the demand for alternative therapeutic options is increasing. To address these problems, we isolated and characterized a Siphoviridae virulent phage, PBC1, and its lytic enzymes. PBC1 showed a very narrow host range, infecting only 1 of 22 B. cereus strains. Phylogenetic analysis based on the major capsid protein revealed that PBC1 is more closely related to the Bacillus clarkii phage BCJA1c and phages of lactic acid bacteria than to the phages infecting B. cereus. Whole-genome comparison showed that the late-gene region, including the terminase gene, structural genes, and holin gene of PBC1, is similar to that from B. cereus temperate phage 250, whereas their endolysins are different. Compared to the extreme host specificity of PBC1, its endolysin, LysPBC1, showed a much broader lytic spectrum, albeit limited to the genus Bacillus. The catalytic domain of LysPBC1 when expressed alone also showed Bacillus-specific lytic activity, which was lower against the B. cereus group but higher against the Bacillus subtilis group than the full-length protein. Taken together, these results suggest that the virulent phage PBC1 is a useful component of a phage cocktail to control B. cereus, even with its exceptionally narrow host range, as it can kill a strain of B. cereus that is not killed by other phages, and that LysPBC1 is an alternative biocontrol agent against B. cereus. PMID:25595773

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

    PubMed

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

    2006-01-01

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

  18. Etiological agents and antimicrobial susceptibility in hospitalized children with acute pyelonephritis.

    PubMed

    Flor-de-Lima, Filipa; Martins, Tânia; Teixeira, Ana; Pinto, Helena; Botelho-Moniz, Edgar; Caldas-Afonso, Alberto

    2015-01-01

    Introdução: A resistência aos antimicrobianos, provocada pela utilização de antibióticos continua a ser um importante problema de saúde pública e uma preocupação para os profissionais de saúde. O nosso objetivo foi conhecer a prevalência local dos uropatógenos e o seu perfil de suscetibilidade aos antimicrobiannos na pielonefrite aguda. Material e Métodos: Estudo prospetivo nas crianças internadas por pielonefrite aguda no internamento de Pediatria de um hospital do norte de Portugal entre 1994-2012. Os agentes etiológicos e o seu perfil de sensibilidade aos antimicrobianos foram avaliados em quatro períodos de tempo (G1: 1994-1997, G2: 2002; G3: 2007; G4: 2012). Resultados: Avaliámos 581 doentes, 66% do sexo feminino, com idade mediana de 22 meses. A Escherichia coli foi o principal uropatógeno e a sua prevalência manteve-se estável durante os últimos 18 anos. Verificou-se um aumento da sensibilidade à amoxicilina/ácido clavulânico de 71% no G1 para 81,5% no G4 (p = 0,001) e uma diminuição da taxa de resistência de 8,7% no G1 para 2,8% G4 (p = 0,008). A sua sensibilidade às cefalosporinas de segunda e terceira geração e nitrofurantoína foi superior a 90% (p = ns). A taxa de resistência ao cotrimoxazol aumentou de 22 % para 26 % (p = 0,008). Discussão: A Escherichia coli continua a ser o uropatogénio mais frequente responsável por pielonefrite aguda, motivo pelo qual o seu perfil de sensibilidade aos antimicrobianos determina a escolha da antibioticoterapia empírica. Conclusões: A amoxicilina/ácido clavulânico mantém-se como escolha de primeira linha para o tratamento empírico da pielonefrite aguda em regime de internamento.

  19. Impact of feed supplementation with antimicrobial agents on growth performance of broiler chickens, Clostridium perfringens and enterococcus counts, and antibiotic resistance phenotypes and distribution of antimicrobial resistance determinants in Escherichia coli isolates.

    PubMed

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

    2007-10-01

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

  20. Antimicrobial susceptibilities of Escherichia coli isolates as agents of community-acquired urinary tract infection (2008–2014)

    PubMed Central

    Yılmaz, Nisel; Ağuş, Neval; Bayram, Arzu; Şamlıoğlu, Pınar; Şirin, M. Cem; Derici, Yeşer Karaca; Hancı, Sevgi Yılmaz

    2016-01-01

    Objective Urinary tract infections (UTIs) are among the most frequently seen community-acquired infections worldwide. E. coli causes 90% of urinary system infections. To guide the empirical therapy, the resistance pattern of E. coli responsible for community-acquired UTI was evaluated throughout a seven-year period in this study. Material and methods The urine cultures of patients with urinary tract infections admitted to outpatient clinics between 1st January 2008 and 31st December 2014 were analyzed. Presence of ≥105 colony-forming units/mL in urine culture media was considered as significant for UTI. Isolated bacteria were identified by standard laboratory techniques or automated system VITEK2 (BioMerieux, France) and BD PhoenixTM 100 (BD, USA), as required. Antibiotic susceptibility testing was performed by Kirby-Bauer disk diffusion method using Clinical Laboratory Standard Institute (CLSI) criteria. Results A total of 13281 uropathogens were isolated. Overall E. coli accounted for 8975 (67%) of all isolates. Resistance rates of E. coli to antimicrobial agents was demonstrated to be as follows: ampicillin 66.9%, cefazolin 30.9%, cefuroxime 30.9%, ceftazidime 14.9%, cefotaxime 28%, cefepime 12%, amoxicillin-clavulanic acid 36.9%, trimethoprim-sulfamethoxazole (TMP-SXT) 20%, ciprofloxacin 49.9%, amikacin 0.3%, gentamycin 24%, nitrofurantoin 0.9%, and fosfomycin 4.3%. There was no resistance to imipenem nor meropenem. The frequency of ESBL-producing E. coli strains was 24%. Conclusion It is concluded that fosfomycin and nitrofurantoin are appropriate empirical therapy for community-acquired UTI empirical therapy, but the fluoroquinolones and the TMP-SXT shall not be used in the emprical treatment of UTI at this stage. In conclusion, as resistance rates show regional differences, it is necessary to regularly examine regional resistance rates to determine the appropriate empiric antibiotic treatment and national antibiotic usage policies must be reorganized

  1. Characterization of the bioactive metabolites from a plant growth-promoting rhizobacteria and their exploitation as antimicrobial and plant growth-promoting agents.

    PubMed

    George, Emrin; Kumar, S Nishanth; Jacob, Jubi; Bommasani, Bhaskara; Lankalapalli, Ravi S; Morang, P; Kumar, B S Dileep

    2015-05-01

    A plant growth-promoting bacterial strain, PM 105, isolated from a tea plantation soil from the North Eastern region of India was identified as Pseudomonas aeruginosa through classical and 16S ribosomal DNA (rDNA) gene sequencing. Further studies with this strain confirmed broad spectrum antifungal activity against ten human and plant pathogenic fungal pathogens viz. Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Aspergillus tubingensis, Candida albicans, Colletotrichum gloeosporioides, Fusarium oxysporum, Pencillium expansum, Rhizoctonia solani, Trichophyton rubrum besides growth-promoting property in cowpea (Vigna unguiculata) and pigeon pea (Cajanus cajan). However, no antibacterial property was exhibited by this strain against the four test bacterial pathogens tested in agar overlay method. The crude bioactive metabolites produced by this strain were isolated with three different solvents that exhibited significant antimicrobial and plant growth-promoting activity. Chloroform extract recorded significant antimicrobial and plant growth-promoting activity. Three major compounds viz. 1-hydroxyphenazine, pyocyanin, and phenazine-1-carboxamide were purified and characterized from crude extracts of this strain by various spectral data. The purified compounds recorded prominent antimicrobial activity but failed to establish the plant growth promotion activity in test crop plants under gnotobiotic conditions. Pyocyanin recorded significant antimicrobial activity, and best activity was recorded against T. rubrum (29 mm), followed by P. expansum (28 mm). These results suggest the use of PM 105 as plant growth-promoting agent in crop plants after successful field trials.

  2. Water metagenomic analysis reveals low bacterial diversity and the presence of antimicrobial residues and resistance genes in a river containing wastewater from backyard aquacultures in the Mekong Delta, Vietnam.

    PubMed

    Nakayama, Tatsuya; Tuyet Hoa, Tran Thi; Harada, Kazuo; Warisaya, Minae; Asayama, Megumi; Hinenoya, Atsushi; Lee, Joon Won; Phu, Tran Minh; Ueda, Shuhei; Sumimura, Yoshinori; Hirata, Kazumasa; Phuong, Nguyen Thanh; Yamamoto, Yoshimasa

    2017-03-01

    The environmental pathways for the dissemination of antibiotic resistance have recently received increased attention. Aquatic environments act as reservoirs or sources of antimicrobial-resistant bacteria, antimicrobial residues, and antimicrobial resistance genes (ARGs). Therefore, it is imperative to identify the role of polluted water in the dissemination of antimicrobial resistance. The aim of this study was to evaluate the antimicrobial residues, ARGs, and microbiota in the freshwater systems of the Mekong Delta. We selected 12 freshwater sites from aquacultures and rivers in Can Tho, Vietnam and analyzed them for 45 antimicrobial residues and 8 ARGs by LC/MS/MS and real-time PCR, respectively. A 16S rDNA-based metagenomic analysis was conducted to characterize the water microbiota. Residues of sulfamethoxazole (10/12) and sulfadimidine (7/12) were widely detected, together with the sulfa-resistance genes sul1 (11/12) and sul2 (9/12). Additionally, sulfamethoxazole residues and the β-lactamase-resistance gene blaCTX-M-1 were detected in eight freshwater systems (8/12), suggesting that these freshwater systems may have been polluted by human activity. The metagenomic analysis showed that all the tested freshwater systems contained the phyla Proteobacteria, Actinobacteria, and Bacteroidetes, representing 64% of the total microbiota. Moreover, the Cai Rang River site (Ri-E), which is located at the merge point of wastewaters from backyard-based aquacultures, contained the genera Polynucleobacter, Variovorax, and Limnohabitans, representing more than 78.4% of the total microbiota. Bacterial diversity analysis showed that the Ri-E exhibited the lowest diversity compared with other regions. Principal coordinate analysis showed that the differences among water microbiotas in backyard-based aquacultures could be explained by the farmers' aquaculture techniques. In conclusion, this study demonstrated a collapse of bacterial diversity at the merge point of wastewaters

  3. General principles of antimicrobial therapy.

    PubMed

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

    2011-02-01

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

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

    PubMed Central

    2013-01-01

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

  5. Pasteurized Whole Milk Confers Reduced Susceptibilities to the Antimicrobial Agents Trimethoprim, Gatifloxacin, Cefotaxime and Tetracycline via the marRAB Locus in Escherichia coli

    PubMed Central

    Peng, Yang; Hernandez, Ricardo L.; Crow, Robert R.; Jones, Suzanna E.; Mathews, Sara A.; Arnold, Ayanna M.; Castillo, Eliseo F.; Moseley, Jennifer M.; Varela, Manuel F.

    2009-01-01

    SUMMARY We inoculated pasteurized whole milk with E. coli strains GC4468 (intact marRAB locus), JHC1096 (Δ marRAB), or AG112 (Δ marR), and incubated each overnight at 37°C. All strains were then recovered from the milk cultures, and susceptibilities to antimicrobial agents were determined by the E-test strip method (CLSI). Cells of strain GC4468, prior to culturing in milk, were susceptible to trimethoprim, gatifloxacin, cefotaxime and tetracycline. After culturing GC4468 in pasteurized milk, however, the MICs increased 1.4-fold for trimethoprim (P ≤ 0.05), 1.5-fold for gatifloxacin (P ≤ 0.05), 2.0-fold for cefotaxime (P = 0.008), and 1.4-fold for tetracycline (P ≥ 0.05). After culturing GC4468 on milk count agar the MICs were enhanced 3.4-fold for trimethoprim (P ≤ 0.05), 10-fold for gatifloxacin (P = 0.001), 7.1-fold for cefotaxime (P = 0.011), and 40.5-fold for tetracycline (P = 0.074), but exhibiting tetracycline resistance with a mean MIC of 74.7 ± 18.47 µg/ml (CLSI). The MICs of the antimicrobial agents for JHC1096 cells after culturing in pasteurized whole milk were indistinguishable (P ≥ 0.05) from baseline MICs measured before culturing in the same type of milk. Thus, E. coli cells harboring the marRAB locus exhibit reduced susceptibilities to multiple antimicrobial agents after culturing in pasteurized whole milk. PMID:19032799

  6. Interscience Conference on Antimicrobial Agents and Chemotherapy--49th annual meeting. Part 2. 12-15 September 2009, San Francisco, CA, USA.

    PubMed

    Turner, Ben; Murch, Lisa

    2009-11-01

    The Interscience Conference on Antimicrobial Agents and Chemotherapy held in San Francisco included topics covering new therapeutic developments for the treatment of infectious diseases. This conference report highlights selected presentations on several antibiotics in development including a broad-spectrum penem beta-lactam antibiotic, a novel siderophore monobactam, as well as other novel antibiotics. Investigational drugs discussed include sulopenem and sulopenem etzadroxil (both Pfizer Inc), BAL-30072 (Basilea Pharmaceutica International Ltd), TP-120 and TP-787 (both Tetraphase Pharmaceuticals Inc), NAI-107 (New Anti Infectives Consortium/NexThera Biosciences) and ABI-200 (AdRem Biotech/US Department of Agriculture).

  7. Key Residues of Outer Membrane Protein OprI Involved in Hexamer Formation and Bacterial Susceptibility to Cationic Antimicrobial Peptides

    PubMed Central

    Chang, Ting-Wei; Wang, Chiu-Feng; Huang, Hsin-Jye; Wang, Iren; Hsu, Shang-Te Danny

    2015-01-01

    Antimicrobial peptides (AMPs) are important components of the host innate defense mechanism against invading pathogens. Our previous studies have shown that the outer membrane protein, OprI from Pseudomonas aeruginosa or its homologue, plays a vital role in the susceptibility of Gram-negative bacteria to cationic α-helical AMPs (Y. M. Lin, S. J. Wu, T. W. Chang, C. F. Wang, C. S. Suen, M. J. Hwang, M. D. Chang, Y. T. Chen, Y. D. Liao, J Biol Chem 285:8985–8994, 2010, http://dx.doi.org/10.1074/jbc.M109.078725; T. W. Chang, Y. M. Lin, C. F. Wang, Y. D. Liao, J Biol Chem 287:418–428, 2012, http://dx.doi.org/10.1074/jbc.M111.290361). Here, we obtained two forms of recombinant OprI: rOprI-F, a hexamer composed of three disulfide-bridged dimers, was active in AMP binding, while rOprI-R, a trimer, was not. All the subunits predominantly consisted of α-helices and exhibited rigid structures with a melting point centered around 76°C. Interestingly, OprI tagged with Escherichia coli signal peptide was expressed in a hexamer, which was anchored on the surface of E. coli, possibly through lipid acids added at the N terminus of OprI and involved in the binding and susceptibility to AMP as native P. aeruginosa OprI. Deletion and mutation studies showed that Cys1 and Asp27 played a key role in hexamer formation and AMP binding, respectively. The increase of OprI hydrophobicity upon AMP binding revealed that it undergoes conformational changes for membrane fusion. Our results showed that OprI on bacterial surfaces is responsible for the recruitment and susceptibility to amphipathic α-helical AMPs and may be used to screen antimicrobials. PMID:26248382

  8. Key Residues of Outer Membrane Protein OprI Involved in Hexamer Formation and Bacterial Susceptibility to Cationic Antimicrobial Peptides.

    PubMed

    Chang, Ting-Wei; Wang, Chiu-Feng; Huang, Hsin-Jye; Wang, Iren; Hsu, Shang-Te Danny; Liao, You-Di

    2015-10-01

    Antimicrobial peptides (AMPs) are important components of the host innate defense mechanism against invading pathogens. Our previous studies have shown that the outer membrane protein, OprI from Pseudomonas aeruginosa or its homologue, plays a vital role in the susceptibility of Gram-negative bacteria to cationic α-helical AMPs (Y. M. Lin, S. J. Wu, T. W. Chang, C. F. Wang, C. S. Suen, M. J. Hwang, M. D. Chang, Y. T. Chen, Y. D. Liao, J Biol Chem 285:8985-8994, 2010, http://dx.doi.org/10.1074/jbc.M109.078725; T. W. Chang, Y. M. Lin, C. F. Wang, Y. D. Liao, J Biol Chem 287:418-428, 2012, http://dx.doi.org/10.1074/jbc.M111.290361). Here, we obtained two forms of recombinant OprI: rOprI-F, a hexamer composed of three disulfide-bridged dimers, was active in AMP binding, while rOprI-R, a trimer, was not. All the subunits predominantly consisted of α-helices and exhibited rigid structures with a melting point centered around 76°C. Interestingly, OprI tagged with Escherichia coli signal peptide was expressed in a hexamer, which was anchored on the surface of E. coli, possibly through lipid acids added at the N terminus of OprI and involved in the binding and susceptibility to AMP as native P. aeruginosa OprI. Deletion and mutation studies showed that Cys1 and Asp27 played a key role in hexamer formation and AMP binding, respectively. The increase of OprI hydrophobicity upon AMP binding revealed that it undergoes conformational changes for membrane fusion. Our results showed that OprI on bacterial surfaces is responsible for the recruitment and susceptibility to amphipathic α-helical AMPs and may be used to screen antimicrobials.

  9. Residual Antimicrobial Activity of MTAD® in Human Dentin After Obturation with Gutta-Percha/AH26 and Resilon/RealSeal SE at Different Time Intervals; An Ex Vivo Study

    PubMed Central

    Bolhari, Behnam; Bahador, Abbas; Assadian, Hadi; Dehghan, Somayyeh

    2014-01-01

    Objectives: To eliminate microorganisms that are responsible for pulpal and periapical infections and to prevent reinfection of the root canal system an effective chemomechanical preparation by irrigants with sustained antimicrobial activity is beneficial. Hereby, we evaluated the residual antibacterial activity of MTAD after canal obturation at different time intervals. Materials and Methods: A total of 120 human single-canalled anterior teeth were selected. The root canals were instrumented to a standardized apical size. Among all, 90 teeth received final irrigation with MTAD and were divided into three groups according to their obturation materials; i.e. gutta-percha/AH26, Resilon/RealSeal SE and positive controls. All these groups were divided into three 1-, 3- and 6-week time interval subgroups. Thirty teeth as negative control had no final irrigation with MTAD, but were obturated with gutta-percha/AH26 or Resilon/RealSealSE. Dentin powder was prepared after 1, 3 and 6 weeks. Dentin powder was exposed to Enterococcus faecalis for 24h and then cultured. Colony Forming Unit (CFU) was counted. Results: Residual antimicrobial activity of MTAD in the teeth obturated with guttapercha/AH26 was significantly higher than the teeth obturated with Resilon/RealSeal SE (p<0.001). It also showed a time dependent decrease in MTAD antimicrobial activity for all groups. The highest antimicrobial activity of MTAD was found in the 1-week positive control and 1-week gutta-percha/AH26 specimens. The lowest antimicrobial activity of MTAD was found in 6-week Resilon/RealSeal SE samples and then the negative controls. Conclusion: MTAD had antimicrobial activity even at the sixth week, although it had a time-dependent decrease. Resilon/Epiphany SE significantly decreased antimicrobial activity of MTAD at all time points. PMID:24910674

  10. Antimicrobial Activity of Lippia Species from the Brazilian Semiarid Region Traditionally Used as Antiseptic and Anti-Infective Agents

    PubMed Central

    Pinto, Cristiana da Purificação; Rodrigues, Velize Dias; Pinto, Fernanda da Purificação; Pinto, Renata da Purificação; Uetanabaro, Ana Paula Trovatti; Pinheiro, Carla Santos Ribeiro; Gadea, Suzana Ferreira Magalhães; Silva, Tânia Regina dos Santos; Lucchese, Angélica Maria

    2013-01-01

    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

  11. Antimicrobial activity of lippia species from the brazilian semiarid region traditionally used as antiseptic and anti-infective agents.

    PubMed

    Pinto, Cristiana da Purificação; Rodrigues, Velize Dias; Pinto, Fernanda da Purificação; Pinto, Renata da Purificação; Uetanabaro, Ana Paula Trovatti; Pinheiro, Carla Santos Ribeiro; Gadea, Suzana Ferreira Magalhães; Silva, Tânia Regina Dos Santos; Lucchese, Angélica Maria

    2013-01-01

    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.

  12. Harnessing the multifunctionality in nature: a bioactive agent release system with self-antimicrobial and immunomodulatory properties.

    PubMed

    Özçelik, Hayriye; Vrana, Nihal Engin; Gudima, Alexandru; Riabov, Vladimir; Gratchev, Alexei; Haikel, Youssef; Metz-Boutigue, Marie-Hélène; Carradò, Adele; Faerber, Jacques; Roland, Thierry; Klüter, Harald; Kzhyshkowska, Julia; Schaaf, Pierre; Lavalle, Philippe

    2015-09-16

    Major problems with biomedical devices in particular implants located in nonsterile environments concern: (i) excessive immune response to the implant, (ii) development of bacterial biofilms, and (iii) yeast and fungi infections. An original multifunctional coating that addresses all these issues concomitantly is developed. A new exponentially growing polyelectrolyte multilayer film based on polyarginine (PAR) and hyaluronic acid (HA) is designed. The films have a strong inhibitory effect on the production of inflammatory cytokines released by human primary macrophage subpopulations. This could reduce potential chronic inflammatory reaction following implantation. Next, it is shown that PAR, due to its positive charges, has an antimicrobial activity in film format against Staphylococcus aureus for 24 h. In order to have a long-term antimicrobial activity, a precursor nanoscale silver coating is deposited on the surface before adding the PAR/HA films. Moreover, the PAR/HA films can be easily further functionalized by embedding antimicrobial peptides, like catestatin (CAT), a natural host defense peptide. This PAR/HA+CAT film proves to be effective as an antimicrobial coating against yeast and fungi and its cytocompatibility is also assessed. Finally, this all-in-one system constitutes an original strategy to limit inflammation and prevents bacteria, yeast, and fungi infections.

  13. In vitro susceptibility of e.faecalis and c.albicans isolates from apical periodontitis to common antimicrobial agents, antibiotics and antifungal medicaments

    PubMed Central

    Yoldas, Oguz; Yilmaz, Sehnaz; Akcimen, Beril; Seydaoglu, Gulsah; Kipalev, Arzu; Koksal, Fatih

    2012-01-01

    The aim of this study was to evaluate in vitro antimicrobial activity of 4 antibiotic agents (for E.faecalis) and 4 antifungal agents (for C.albicans) by agar dilution method. Additionally, modified strip diffusion method was used for detection of in vitro antimicrobial activities of 5% NaOCl, 2.5% NaOCl, 17% EDTA and 2% CHX and agar diffusion method for detection of in vitro susceptibilities of three intracanal medicaments for 18 E.faecalis and 18 C.albicans isolates from primary and secondary root canal infection. Isolates were recovered from 231 endodontic samples of patients, with the need of root canal treatment and retreatment. All tested E.faecalis isolates showed resistance to antibiotics. For irrigation solutions, 2% CHX was more effective in eliminating E.faecalis but 5% NaOCl showed larger inhibition zone than 2.5% NaOCl, 17% EDTA and 2% CHX. For intracanal medication, Ca(OH)2-CHX worked efficiently in killing E.faecalis isolates compared to Ca(OH)2-Steril saline solution, Ca(OH)2-Glycerin. For C.albicans, 18 isolates were susceptible to amphotericin B, nistatin, fluconazole but showed resistance to ketoconazole. 5% NaOCl was more effective in eliminating and produced larger inhibition zone compared to 2.5% NaOCl, 17% EDTA and 2% CHX. Ca(OH)2-Glycerin intracanal medication was better in eliminating C.albicans isolates and produced larger inhibition zone compared to other Ca(OH)2 medicaments. Key words:E.faecalis, C.albicans, antimicrobial, antibiotic, antifungal. PMID:24558517

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

    NASA Astrophysics Data System (ADS)

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

    2012-05-01

    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 μm length and average diameters of up to 160 nm. Drug release experiments with the model antibiotic vancomycin and with antibacterial silver ions showed that the increased surface area of the anodized samples enabled them to be loaded with up to 450% more active agent than the untreated Ti surfaces. Significant surface-dependent differences in the release kinetics of vancomycin were observed. In comparison to surfaces anodized in an aqueous electrolyte, the release of the antibiotic from surfaces anodized in an electrolyte based on ethylene glycol was significantly retarded, with a release of noticeable amounts over a period of more than 300 days. Loading of nanotube surfaces fabricated in aqueous electrolyte with silver ions revealed increased amounts of adsorbed silver by up to 230%, while the release kinetics showed significant differences in comparison to untreated Ti. It was concluded that nanotube arrays on favored medical implant materials have a high potential for loading with antimicrobial agents and also provide the possibility of tailored release kinetics by variation of anodization parameters.

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

    PubMed

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

    2006-03-10

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

  16. N-Succinimidyl guanidinomethyl iodobenzoate protein radiohalogenation agents: Influence of isomeric substitution on radiolabeling and target cell residualization

    PubMed Central

    Choi, Jaeyeon; Vaidyanathan, Ganesan; Koumarianou, Eftychia; McDougald, Darryl; Pruszynski, Marek; Osada, Takuya; Lahoutte, Tony; Lyerly, H. Kim; Zalutsky, Michael R.

    2014-01-01

    Introduction N-succinimidyl 4-guanidinomethyl-3-[*I]iodobenzoate ([*I]SGMIB) has shown promise for the radioiodination of monoclonal antibodies (mAbs) and other proteins that undergo extensive internalization after receptor binding, enhancing tumor targeting compared to direct electrophilic radioiodination. However, radiochemical yields for [131I]SGMIB synthesis are low, which we hypothesize is due to steric hindrance from the Boc-protected guanidinomethyl group ortho to the tin moiety. To overcome this, we developed the isomeric compound, N-succinimidyl 3-guanidinomethyl-5-[131I]iodobenzoate (iso-[131I]SGMIB) wherein this bulky group was moved from ortho to meta position. Methods Boc2-iso-SGMIB standard and its tin precursor, N-succinimidyl 3-((1,2-bis(tert-butoxycarbonyl)guanidino)methyl)-5-(trimethylstannyl)benzoate (Boc2-iso-SGMTB), were synthesized using two disparate routes, and iso-[*I]SGMIB synthesized from the tin precursor. Two HER2-targeted vectors — trastuzumab (Tras) and a nanobody 5F7 (Nb) — were labeled using iso-[*I]SGMIB and [*I]SGMIB. Paired-label internalization assays in vitro with both proteins, and biodistribution in vivo with trastuzumab, labeled using the two isomeric prosthetic agents were performed. Results When the reactions were performed under identical conditions, radioiodination yields for the synthesis of Boc2-iso-[131I]SGMIB were significantly higher than those for Boc2-[131I]SGMIB (70.7 ± 2.0% vs 56.5 ± 5.5%). With both Nb and trastuzumab, conjugation efficiency also was higher with iso-[131I]SGMIB than with [131I]SGMIB (Nb, 33.1 ± 7.1% vs 28.9 ± 13.0%; Tras, 45.1 ± 4.5% vs 34.8 ± 10.3%); however, the differences were not statistically significant. Internalization assays performed on BT474 cells with 5F7 Nb indicated similar residualizing capacity over 6 h; however, at 24 h, radioactivity retained intracellularly for iso-[131I]SGMIB-Nb was lower than for [125I]SGMIB-Nb (46.4 ± 1.3% vs 56.5 ± 2.5%); similar results were

  17. Capping Agent-Dependent Toxicity and Antimicrobial Activity of Silver Nanoparticles: An In Vitro Study. Concerns about Potential Application in Dental Practice

    PubMed Central

    Niska, Karolina; Knap, Narcyz; Kędzia, Anna; Jaskiewicz, Maciej; Kamysz, Wojciech; Inkielewicz-Stepniak, Iwona

    2016-01-01

    Objectives: In dentistry, silver nanoparticles (AgNPs) have drawn particular attention because of their wide antimicrobial activity spectrum. However, controversial information on AgNPs toxicity limited their use in oral infections. Therefore, the aim of the present study was to evaluate the antibacterial activities against a panel of oral pathogenic bacteria and bacterial biofilms together with potential cytotoxic effects on human gingival fibroblasts of 10 nm AgNPs: non-functionalized - uncapped (AgNPs-UC) as well as surface-functionalized with capping agent: lipoic acid (AgNPs-LA), polyethylene glycol (AgNPs-PEG) or tannic acid (AgNPs-TA) using silver nitrate (AgNO3) as control. Methods: The interaction of AgNPs with human gingival fibroblast cells (HGF-1) was evaluated using the mitochondrial metabolic potential assay (MTT). Antimicrobial activity of AgNPs was tested against anaerobic Gram-positive and Gram-negative bacteria isolated from patients with oral cavity and respiratory tract infections, and selected aerobic Staphylococci strains. Minimal inhibitory concentration (MIC) values were determined by the agar dilution method for anaerobic bacteria or broth microdilution method for reference Staphylococci strains and Streptococcus mutans. These strains were also used for antibiofilm activity of AgNPs. Results: The highest antimicrobial activities at nontoxic concentrations were observed for the uncapped AgNPs and the AgNPs capped with LA. It was found that AgNPs-LA and AgNPs-PEG demonstrated lower cytotoxicity as compared with the AgNPs-TA or AgNPs-UC in the gingival fibroblast model. All of the tested nanoparticles proved less toxic and demonstrated wider spectrum of antimicrobial activities than AgNO3 solution. Additionally, AgNPs-LA eradicated Staphylococcus epidermidis and Streptococcus mutans 1-day biofilm at concentration nontoxic to oral cells. Conclusions: Our results proved that a capping agent had significant influence on the antibacterial

  18. Capping Agent-Dependent Toxicity and Antimicrobial Activity of Silver Nanoparticles: An In Vitro Study. Concerns about Potential Application in Dental Practice.

    PubMed

    Niska, Karolina; Knap, Narcyz; Kędzia, Anna; Jaskiewicz, Maciej; Kamysz, Wojciech; Inkielewicz-Stepniak, Iwona

    2016-01-01

    Objectives: In dentistry, silver nanoparticles (AgNPs) have drawn particular attention because of their wide antimicrobial activity spectrum. However, controversial information on AgNPs toxicity limited their use in oral infections. Therefore, the aim of the present study was to evaluate the antibacterial activities against a panel of oral pathogenic bacteria and bacterial biofilms together with potential cytotoxic effects on human gingival fibroblasts of 10 nm AgNPs: non-functionalized - uncapped (AgNPs-UC) as well as surface-functionalized with capping agent: lipoic acid (AgNPs-LA), polyethylene glycol (AgNPs-PEG) or tannic acid (AgNPs-TA) using silver nitrate (AgNO3) as control. Methods: The interaction of AgNPs with human gingival fibroblast cells (HGF-1) was evaluated using the mitochondrial metabolic potential assay (MTT). Antimicrobial activity of AgNPs was tested against anaerobic Gram-positive and Gram-negative bacteria isolated from patients with oral cavity and respiratory tract infections, and selected aerobic Staphylococci strains. Minimal inhibitory concentration (MIC) values were determined by the agar dilution method for anaerobic bacteria or broth microdilution method for reference Staphylococci strains and Streptococcus mutans. These strains were also used for antibiofilm activity of AgNPs. Results: The highest antimicrobial activities at nontoxic concentrations were observed for the uncapped AgNPs and the AgNPs capped with LA. It was found that AgNPs-LA and AgNPs-PEG demonstrated lower cytotoxicity as compared with the AgNPs-TA or AgNPs-UC in the gingival fibroblast model. All of the tested nanoparticles proved less toxic and demonstrated wider spectrum of antimicrobial activities than AgNO3 solution. Additionally, AgNPs-LA eradicated Staphylococcus epidermidis and Streptococcus mutans 1-day biofilm at concentration nontoxic to oral cells. Conclusions: Our results proved that a capping agent had significant influence on the antibacterial

  19. Structural, textural and morphological characteristics of tannins from Acacia mearnsii encapsulated using sol-gel methods: Applications as antimicrobial agents.

    PubMed

    Dos Santos, Cristiane; Vargas, Álvaro; Fronza, Ney; Dos Santos, João Henrique Zimnoch

    2017-03-01

    Tannins from Acacia mearnsii were encapsulated using four different sol-gel methods acid (SGAR), basic (SGBR), silicate (SGSR) and non-hydrolytic (SGNHR) routes. The hybrid materials were analyzed using a set of techniques to characterize their structure, texture and morphology. The antimicrobial performance of the encapsulated materials was evaluated against different microorganisms (Staphylococcus aureus, Escherichia coli, Aspergillus niger and Candida sp.). The data showed that the encapsulation route significantly affects the characteristics of the resulting hybrid materials. Better functional performances were obtained using the silicate route, which produced mesoporous materials with a small surface area (0.96m(2)g(-1)) and small particle size (<1nm). These characteristics promoted the gradual release of tannins in an aqueous medium and improved their interactions with microorganisms. Furthermore, the process demonstrated the preservation of tannins after synthesis and increased antimicrobial activity (via a controlled tannin release), as demonstrated by the moderate activity against filamentous fungi and yeast.

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

    PubMed

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

    2010-06-01

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

  1. Binary and Tertiary Mixtures of Satureja hortensis and Origanum vulgare Essential Oils as Potent Antimicrobial Agents Against Helicobacter pylori.

    PubMed

    Lesjak, Marija; Simin, Natasa; Orcic, Dejan; Franciskovic, Marina; Knezevic, Petar; Beara, Ivana; Aleksic, Verica; Svircev, Emilija; Buzas, Krisztina; Mimica-Dukic, Neda

    2016-03-01

    Essential oils possess strong antimicrobial activity, even against multiresistant Helicobacter pylori. Available therapies against H. pylori infection have multiple disadvantages, indicating a great need for a development of new therapeutics. The purpose of this study was to develop a potent natural product based anti-H. pylori formulation. First, anti-H. pylori activity of nine essential oils was determined, after which the most active oils were mixed in various ratios for further testing. Satureja hortensis, Origanum vulgare subsp. vulgare and O. vulgare subsp. hirtum essential oils expressed the highest activity (MIC = 2 μL mL(-1)). Their binary and ternary mixtures exhibited notably higher antimicrobial activity (MIC ≤ 2 μL mL(-1)). The most active was the mixture of S. hortensis and O. vulgare subsp. hirtum oils in volume ratio 2:1, which expressed 4 times higher activity than individual oils (MIC = 0.5 μL mL(-1)). According to GC-MS, both oils in the mixture were characterized by high content of phenols (48-73%), with carvacrol as the main carrier of antimicrobial activity. Presented in vitro study pointed out binary mixture of S. hortensis and O. vulgare subsp. hirtum essential oils in volume ratio 2:1 as promising candidate for further in vivo studies targeting H. pylori infection.

  2. [Antimicrobial prophylaxis in surgery].

    PubMed

    Cisneros, José Miguel; Rodríguez-Baño, Jesús; Mensa, José; Trilla, Antoni; Cainzos, Miguel

    2002-01-01

    Antimicrobial prophylaxis in surgery refers to a very brief course of an antimicrobial agent initiated just before the start of the procedure. The efficacy of antimicrobials to prevent postoperative infection at the site of surgery (incisional superficial, incisional deep, or organ/space infection) has been demonstrated for many surgical procedures. Nevertheless, the majority of studies centering on the quality of preoperative prophylaxis have found that a high percentage of the antimicrobials used are inappropriate for this purpose. This work discusses the scientific basis for antimicrobial prophylaxis, provides general recommendations for its correct use and specific recommendations for various types of surgery. The guidelines for surgical antimicrobial prophylaxis are based on results from well-designed studies, whenever possible. These guidelines are focussed on reducing the incidence of infection at the surgical site while minimizing the contribution of preoperative administration of antimicrobials to the development of bacterial resistance.

  3. Saturation mutagenesis of selected residues of the α-peptide of the lantibiotic lacticin 3147 yields a derivative with enhanced antimicrobial activity

    PubMed Central

    Field, Des; Molloy, Evelyn M; Iancu, Catalin; Draper, Lorraine A; O' Connor, Paula M; Cotter, Paul D; Hill, Colin; Ross, R Paul

    2013-01-01

    Summary The lantibiotic lacticin 3147 consists of two ribosomally synthesized and post-translationally modified antimicrobial peptides, Ltnα and Ltnβ, which act synergistically against a wide range of Gram-positive microorganisms. We performed saturation mutagenesis of specific residues of Ltnα to determine their functional importance. The results establish that Ltnα is more tolerant to change than previously suggested by alanine scanning mutagenesis. One substitution, LtnαH23S, was identified which improved the specific activity of lacticin 3147 against one pathogenic strain, Staphylococcus aureus NCDO1499. This represents the first occasion upon which the activity of a two peptide lantibiotic has been enhanced through bioengineering. Funding Information Work in the authors' laboratory is supported by the Irish Government under the National Development Plan; by the Irish Research Council for Science Engineering and Technology (IRCSET); by Enterprise Ireland; and by Science Foundation Ireland (SFI), through the Alimentary Pharmabiotic Centre (APC) at University College Cork, Ireland, which is supported by the SFI-funded Centre for Science, Engineering and Technology (SFI-CSET) and provided P.D.C., C.H and R.P.R. with SFI Principal Investigator funding. PMID:23433070

  4. Mechanistic investigation of the interaction between bisquaternary antimicrobial agents and phospholipids by liquid secondary ion mass spectrometry and differential scanning calorimetry.

    PubMed

    Pashynskaya, V A; Kosevich, M V; Gömöry, A; Vashchenko, O V; Lisetski, L N

    2002-01-01

    Mechanisms of interaction between the antimicrobial drugs decamethoxinum and aethonium, which are based on bisquaternary ammonium compounds, and a phospholipid component of biological membranes, dipalmitoylphosphatidylcholine, were studied by means of liquid secondary ion mass spectrometry (LSIMS) and differential scanning calorimetry (DSC). Supramolecular complexes of the drugs with this phospholipid were recorded under secondary ion mass spectrometric conditions. The dependence of the structures of these complexes on structural parameters of the dications of the bisquaternary ammonium compounds was demonstrated. Tandem mass spectrometric investigations of the metastable decay of doubly charged ions of decamethoxinum and aethonium complexes with dipalmitoylphosphatidylcholine allowed estimation of structural parameters of these complexes in the gas phase. Interactions of decamethoxinum and aethonium with model membrane assemblies built from hydrated dipalmitoylphosphatidylcholine were studied using DSC. It was shown that while both drugs can interact with model membranes, the mechanisms of such interactions for decamethoxinum and aethonium differ. The correlation between the nature of these interactions and structural and electronic parameters of the dications of the two bisquaternary agents is discussed. Interpretation of combined mass spectrometric and calorimetric experimental data led to proposals that the molecular mechanisms of antimicrobial action of bisquaternary ammonium compounds are related to their effect on the membrane phospholipid components of microbial cells.

  5. Characterization of CTX-M enzymes, quinolone resistance determinants, and antimicrobial residues from hospital sewage, wastewater treatment plant, and river water.

    PubMed

    Conte, Danieli; Palmeiro, Jussara Kasuko; da Silva Nogueira, Keite; de Lima, Thiago Marenda Rosa; Cardoso, Marco André; Pontarolo, Roberto; Degaut Pontes, Flávia Lada; Dalla-Costa, Libera Maria

    2017-02-01

    Multidrug-resistant (MDR) bacteria are widespread in hospitals and have been increasingly isolated from aquatic environments. The aim of the present study was to characterize extended-spectrum β-lactamase (ESBL) and quinolone-resistant Enterobacteriaceae from a hospital effluent, sanitary effluent, inflow sewage, aeration tank, and outflow sewage within a wastewater treatment plant (WWTP), as well as river water upstream and downstream (URW and DRW, respectively), of the point where the WWTP treated effluent was discharged. β-lactamase (bla) genes, plasmid-mediated quinolone resistance (PMQR), and quinolone resistance-determining regions (QRDRs) were assessed by amplification and sequencing in 55 ESBL-positive and/or quinolone-resistant isolates. Ciprofloxacin residue was evaluated by high performance liquid chromatography. ESBL-producing isolates were identified in both raw (n=29) and treated (n=26) water; they included Escherichia coli (32), Klebsiella pneumoniae (22) and Klebsiella oxytoca (1). Resistance to both cephalosporins and quinolone was observed in 34.4% of E. coli and 27.3% of K. pneumoniae. Resistance to carbapenems was found in 5.4% of K. pneumoniae and in K. oxytoca. Results indicate the presence of blaCTX-M (51/55, 92.7%) and blaSHV (8/55, 14.5%) ESBLs, and blaGES (2/55, 3.6%) carbapenemase-encoding resistance determinants. Genes conferring quinolone resistance were detected at all sites, except in the inflow sewage and aeration tanks. Quinolone resistance was primarily attributed to amino acid substitutions in the QRDR of GyrA (47%) or to the presence of PMQR (aac-(6')-Ib-cr, oqxAB, qnrS, and/or qnrB; 52.9%) determinants. Ciprofloxacin residue was absent only from URW. Our results have shown strains carrying ESBL genes, PMQR determinants, and mutations in the gyrA QRDR genes mainly in hospital effluent, URW, and DRW samples. Antimicrobial use, and the inefficient removal of MDR bacteria and antibiotic residue during sewage treatment, may

  6. In Vitro Approach for Identification of the Most Effective Agents for Antimicrobial Lock Therapy in the Treatment of Intravascular Catheter-Related Infections Caused by Staphylococcus aureus

    PubMed Central

    Hogan, S.; Zapotoczna, M.; Stevens, N. T.; Humphreys, H.; O'Gara, J. P.

    2016-01-01

    Infection of intravascular catheters by Staphylococcus aureus is a significant risk factor within the health care setting. To treat these infections and attempt salvage of an intravascular catheter, antimicrobial lock solutions (ALSs) are being increasingly used. However, the most effective ALSs against these biofilm-mediated infections have yet to be determined, and clinical practice varies greatly. The purpose of this study was to evaluate and compare the efficacies of antibiotics and antiseptics in current clinical use against biofilms produced by reference and clinical isolates of S. aureus. Static and flow biofilm assays were developed using newly described in vivo-relevant conditions to examine the effect of each agent on S. aureus within the biofilm matrix. The antibiotics daptomycin, tigecycline, and rifampin and the antiseptics ethanol and Taurolock inactivated established S. aureus biofilms, while other commonly used antistaphylococcal antibiotics and antiseptic agents were less effective. These findings were confirmed by live/dead staining of S. aureus biofilms formed and treated within a flow cell model. The results from this study demonstrate the most effective clinically used agents and their concentrations which should be used within an ALS to treat S. aureus-mediated intravascular catheter-related infections. PMID:26926633

  7. 1,5-Benzodiazepine derivatives as potential antimicrobial agents: design, synthesis, biological evaluation, and structure-activity relationships.

    PubMed

    Wang, Lan-Zhi; Li, Xiao-Qing; An, Ying-Shuang

    2015-05-21

    36 Novel 1,5-benzodiazepine derivatives were rationally designed and synthesized according to the principle of superposition of bioactive substructures by the combination of 1,5-benzodiazepines, thiophene or thiazole and ester group. The structures of the target compounds have been characterized by IR, (1)H NMR, (13)C NMR, MS and elemental analysis. The structure of 1v was further determined using X-ray single crystal diffraction. All synthesized 1,5-benzodiazepine derivatives were evaluated for their in vitro antimicrobial activity against C. neoformans, C. neoformans clinical isolates, C. albicans, E. coli and S. aureus. The bioactive assay results revealed that most of the 1,5-benzodiazepine derivatives exhibited considerable potency against all of the tested strains. In particular, compounds 1v and 1w (MIC: 2-6 μg mL(-1), MFC: 10-14 μg mL(-1)) exhibited excellent antifungal activity and were found to be 32-64 and 9-12.8 times more potent than the reference drugs against C. neoformans, respectively. Moreover, compound (MIC: 40 μg mL(-1)) displayed equipotent antibacterial activity against E. coli and S. aureus compared to the reference drugs. The most potent of the synthesized compounds 1v and 1w were further studied by evaluating their cytotoxicities, and the results showed that they had relatively low level cytotoxicity for BV2 cell. A preliminary study of the structure-activity relationship revealed that substituents in the phenyl ring and the thiophene ring had a great effect on the antimicrobial activity of these compounds. In addition, the thiazole ring at C2 may be a pharmacophore of these compounds and COOC2H5 group at C3 is the best substituent for the maintenance of antimicrobial activities at low concentrations (1.5625 μg per disc).

  8. Agents.

    PubMed

    Chambers, David W

    2002-01-01

    Although health care is inherently an economic activity, it is inadequately described as a market process. An alternative, grounded in organizational economic theory, is to view professionals and many others as agents, contracted to advance the best interests of their principals (patients). This view untangles some of the ethical conflicts in dentistry. It also helps identify major controllable costs in dentistry and suggests that dentists can act as a group to increase or decrease agency costs, primarily by controlling the bad actors who damage the value of all dentists.

  9. First report on rapid screening of nanomaterial-based antimicrobial agents against β-lactamase resistance using pGLO plasmid transformed Escherichia coli HB 101 K-12

    NASA Astrophysics Data System (ADS)

    Raj, M. Alpha; Muralidhar, Y.; Sravanthi, M.; Prasad, T. N. V. K. V.; Nissipriya, M.; Reddy, P. Sirisha; Neelima, T. Shoba; Reddy, G. Dilip; Adilaxmamma, K.; Kumar, P. Anand; Krishna, T. Giridhara

    2016-08-01

    Combating antibiotic resistance requires discovery of novel antimicrobials effective against resistant bacteria. Herein, we present for the first time, pGLO plasmid transformed Escherichia coli HB 101 K 12 as novel model for screening of nanomaterial-based antimicrobial agents against β-lactamase resistance. E. coli HB 101 was transformed by pGLO plasmid in the presence of calcium chloride (50 mM; pH 6.1) aided by heat shock (0-42-0 °C). The transformed bacteria were grown on Luria-Bertani agar containing ampicillin (amp) and arabinose (ara). The transformed culture was able to grow in the presence of ampicillin and also exhibited fluorescence under UV light. Both untransformed and transformed bacteria were used for screening citrate-mediated nanosilver (CNS), aloin-mediated nanosilver (ANS), 11-α-keto-boswellic acid (AKBA)-mediated nanosilver (BNS); nanozinc oxide, nanomanganese oxide (NMO) and phytochemicals such as aloin and AKBA. Minimum inhibitory concentrations (MIC) were obtained by microplate method using ρ-iodo nitro tetrazolium indicator. All the compounds were effective against transformed bacteria except NMO and AKBA. Transformed bacteria exhibited reverse cross resistance against aloin. ANS showed the highest antibacterial activity with a MIC of 0.32 ppm followed by BNS (10.32 ppm), CNS (20.64 ppm) and NZO (34.83 ppm). Thus, pGLO plasmid can be used to induce resistance against β-lactam antibiotics and the model can be used for rapid screening of new antibacterial agents effective against resistant bacteria.

  10. Antimicrobial evaluation of new metallic complexes with xylitol active against P. aeruginosa and C. albicans: MIC determination, post-agent effect and Zn-uptake.

    PubMed

    Santi, E; Facchin, G; Faccio, R; Barroso, R P; Costa-Filho, A J; Borthagaray, G; Torre, M H

    2016-02-01

    Xylitol (xylH5) is metabolized via the pentose pathway in humans, but it is unsuitable as an energy source for many microorganisms where it produces a xylitol-induced growth inhibition and disturbance in protein synthesis. For this reason, xylitol is used in the prophylaxis of several infections. In the search of better antimicrobial agents, new copper and zinc complexes with xylitol were synthesized and characterized by analytical and spectrosco pic methods: Na2[Cu3(xylH−4)2]·NaCl·4.5H2O (Cu-xyl) and [Zn4(xylH−4)2(H2O)2]·NaCl·3H2O (Zn-xyl). Both copper and zinc complexes presented higher MIC against Pseudomona aeruginosa than the free xylitol while two different behaviors were found against Candida albicans depending on the complex. The growth curves showed that Cu-xyl presented lower activity than the free ligand during all the studied period. In the case of Znxyl the growth curves showed that the inhibition of the microorganism growth in the first stage was equivalent to that of xylitol but in the second stage (after 18 h) Zn-xyl inhibited more. Besides, the PAE (post agent effect)obtained for Zn-xyl and xyl showed that the recovery from the damage of microbial cells had a delay of 14 and 13 h respectively. This behavior could be useful in prophylaxis treatments for infectious diseases where it is important that the antimicrobial effect lasts longer. With the aim to understand the microbiological activities the analysis of the particle size, lipophilicity and Zn uptake was performed.

  11. From individual to collective immunity: the role of the venom as antimicrobial agent in the Stenogastrinae wasp societies.

    PubMed

    Baracchi, David; Mazza, Giuseppe; Turillazzi, Stefano

    2012-01-01

    Sociality is associated with an increased risk of disease transmission and one of the first defense of the insect colonies is represented by antimicrobial secretions. In many eusocial hymenopteran species venom glands represent one of the most important source of antimicrobial substances. It is known that in highly eusocial species the venom is spread on both the cuticle of insects and the comb, thus becoming a component of the so called "social immunity". So far, it is never been ascertained whether this phenomenon is also present in more primitively eusocial and incipiently eusocial groups. Using incipiently eusocial hover wasps as model, we demonstrate that venom is present on insect cuticles and that it strongly acts against microorganisms. By contrast, the nest, regardless of materials, does not represent a ''medium" where the venom is deposited by wasps in order to act as a social antiseptic weapon. Our findings discussed in an evolutionary perspective indicate that a certain degree of sociality or a sufficient number of individuals in an insect society are thresholds to be reached for the rise of complex and efficient forms of collective and social immunity as mechanisms of resistance to diseases.

  12. Biological evaluation of some new N-(2,6-dimethoxypyrimidinyl) thioureido benzenesulfonamide derivatives as potential antimicrobial and anticancer agents.

    PubMed

    Ghorab, Mostafa M; Alsaid, Mansour S; El-Gaby, Mohamed S A; Safwat, Nesreen A; Elaasser, Mahmoud M; Soliman, Aiten M

    2016-11-29

    A series of novel heterocyclic thioureas 3a-u containing sulfonamide moiety have been synthesized by the condensation of isothiocyanatobenzenesulfonamide 2 with a variety of heterocyclic amines. The newly synthesized heterocyclic thioureas were investigated for their antimicrobial and anticancer activity. The in vitro antibacterial and antifungal activity were done using well diffusion method. Interestingly, compounds 3j and 3m, showed similar or better activity compared with the reference drug against the tested microorganisms. Although, 3j was less active among its analogues to inhibit the breast carcinoma cells, it exhibit strong broad spectrum antimicrobial activities. However, The results of the cytotoxic activity revealed that compound 3p was the most active against the breast carcinoma cell line (MCF-7) giving promising IC50 value of 1.72 μg/mL, compared with reference drug (5-flourouracil) with IC50 value of 4.8 μg/mL. The most potent compounds in cytotoxic activity 3b and 3p were further docked inside the active site of CAIX and were found to exhibit a proper binding with the active site amino acids according to their bond lengths, angles and conformational energy.

  13. Synthesis and Antibacterial Evaluation of New Thione Substituted 1,2,4-Triazole Schiff Bases as Novel Antimicrobial Agents.

    PubMed

    Akbari Dilmaghani, Karim; Nasuhi Pur, Fazel; Hatami Nezhad, Mahnaz

    2015-01-01

    The condensation reaction of 5-(4-aminophenyl)-4-phenyl-1,2,4-triazole-3-thione with salicylaldehyde, 4-hydroxybenzaldehyde, 5-chlorosalicylaldehyde, 5-bromosalicylaldehyde, 2-nitrobenzaldehyde, 3-nitrobenzaldehyde, 4-nitrobenzaldehyde and 4-methoxybenzaldehyde in methanol results in series of new Schiff bases. The structure of Schiff bases were confirmed by (1)H NMR, (13)C NMR, IR and mass spectroscopy. The synthesized compounds were tested for their antimicrobial activity against bacterial (Gram negative and Gram positive) strains in-vitro. The synthetic compounds showed different inhibition zones against tested bacterial strains. All compounds showed significant antiproliferative activity against Acinetobacter calcoaceticus ATCC 23055. In detail, Entrococcus faecalis (Gram positive) was resistant to all prepared compounds, whereas, A. calcoaceticus (Gram negative) was sensitive to all compounds especially 5c, 5d and 4. S. aureus (Gram positive, relatively resistant to antimicrobials) showed limited sensitivity to only 5c and 5d, and it was resistant to all other compounds and only 5c exhibited low activity against P. aeruginosa (Gram negative). The best results belonged to 5c that showed high activity against A. calcoaceticus (33 mm) as well as S. aureus (20 mm).

  14. Synthesis and Antibacterial Evaluation of New Thione Substituted 1,2,4-Triazole Schiff Bases as Novel Antimicrobial Agents

    PubMed Central

    Akbari Dilmaghani, Karim; Nasuhi Pur, Fazel; Hatami Nezhad, Mahnaz

    2015-01-01

    The condensation reaction of 5-(4-aminophenyl)-4-phenyl-1,2,4-triazole-3-thione with salicylaldehyde, 4-hydroxybenzaldehyde, 5-chlorosalicylaldehyde, 5-bromosalicylaldehyde, 2-nitrobenzaldehyde, 3-nitrobenzaldehyde, 4-nitrobenzaldehyde and 4-methoxybenzaldehyde in methanol results in series of new Schiff bases. The structure of Schiff bases were confirmed by 1H NMR, 13C NMR, IR and mass spectroscopy. The synthesized compounds were tested for their antimicrobial activity against bacterial (Gram negative and Gram positive) strains in-vitro. The synthetic compounds showed different inhibition zones against tested bacterial strains. All compounds showed significant antiproliferative activity against Acinetobacter calcoaceticus ATCC 23055. In detail, Entrococcus faecalis (Gram positive) was resistant to all prepared compounds, whereas, A. calcoaceticus (Gram negative) was sensitive to all compounds especially 5c, 5d and 4. S. aureus (Gram positive, relatively resistant to antimicrobials) showed limited sensitivity to only 5c and 5d, and it was resistant to all other compounds and only 5c exhibited low activity against P. aeruginosa (Gram negative). The best results belonged to 5c that showed high activity against A. calcoaceticus (33 mm) as well as S. aureus (20 mm). PMID:26330857

  15. Exploring the use of natural antimicrobial agents and pulsed electric fields to control spoilage bacteria during a beer production process.

    PubMed

    Galvagno, M A; Gil, G R; Iannone, L J; Cerrutti, P

    2007-01-01

    Different natural antimicrobials affected viability of bacterial contaminants isolated at critical steps during a beer production process. In the presence of 1 mg/ml chitosan and 0.3 mg/ml hops, the viability of Escherichia coli in an all malt barley extract wort could be reduced to 0.7 and 0.1% respectively after 2 hour- incubation at 4 degrees C. The addition of 0.0002 mg/ml nisin, 0.1 mg/ml chitosan or 0.3 mg/ml hops, selectively inhibited growth of Pediococcus sp. in more than 10,000 times with respect to brewing yeast in a mixed culture. In the presence of 0.1 mg ml chitosan in beer, no viable cells of the thermoresistant strain Bacillus megaterium were detected. Nisin, chitosan and hops increased microbiological stability during storage of a local commercial beer inoculated with Lactobacillus plantarum or Pediococcus sp. isolated from wort. Pulsed Electric Field (PEF) (8 kV/cm, 3 pulses) application enhanced antibacterial activity of nisin and hops but not that of chitosan. The results herein obtained suggest that the use of these antimicrobial compounds in isolation or in combination with PEF would be effective to control bacterial contamination during beer production and storage.

  16. Frequency of resistance to methicillin and other antimicrobial agents among Staphylococcus aureus strains isolated from pigs and their human handlers in Trinidad

    PubMed Central

    Gordon, Annika; Marshall, Jennelle; Ramdass, Kris; Stewart-Johnson, Alva; Adesiyun, Abiodun

    2014-01-01

    Background Methicillin-resistant Staphylococcus aureus (MRSA) has emerged recently worldwide in production animals, particularly pigs and veal calves, which act as reservoirs for MRSA strains for human infection. The study determined the prevalence of MRSA and other resistant strains of S. aureus isolated from the anterior nares of pigs and human handlers on pig farms in Trinidad. Methods Isolation of S. aureus was done by concurrently inoculating Baird-Parker agar (BPA) and Chromagar MRSA (CHROM) with swab samples and isolates were identified using standard methods. Suspect MRSA isolates from Chromagar and BPA were subjected to confirmatory test using Oxoid PBP2 latex agglutination test. The disc diffusion method was used to determine resistance to antimicrobial agents. Results The frequency of isolation of MRSA was 2.1% (15 of 723) for pigs but 0.0% (0 of 72) for humans. Generally, for isolates of S. aureus from humans there was a high frequency of resistance compared with those from pigs, which had moderate resistance to the following antimicrobials: penicillin G (54.5%, 51.5%), ampicillin (59.1%, 49.5%), and streptomycin (59.1%, 37.1%), respectively. There was moderate resistance to tetracycline (36.4%, 41.2%) and gentamycin (27.2%, 23.7%) for human and pig S. aureus isolates, respectively, and low resistance to sulfamethoxazole-trimethoprim (4.5%, 6.2%) and norfloxacin (9.1%, 12.4%), respectively. The frequency of resistance to oxacillin by the disc method was 36.4 and 34.0% from S. aureus isolates from humans and pigs, respectively. Out of a total of 78 isolates of S. aureus from both human and pig sources that were resistant to oxacillin by the disc diffusion method, only 15 (19.2%) were confirmed as MRSA by the PBP'2 latex test kit. Conclusions The detection of MRSA strains in pigs, albeit at a low frequency, coupled with a high frequency of resistance to commonly used antimicrobial agents in pig and humans could have zoonotic and therapeutic implications

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

    PubMed

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

    2011-01-01

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

  18. Antimicrobial agent of susceptibilities and antiseptic resistance gene distribution among methicillin-resistant Staphylococcus aureus isolates from patients with impetigo and staphylococcal scalded skin syndrome.

    PubMed

    Noguchi, Norihisa; Nakaminami, Hidemasa; Nishijima, Setsuko; Kurokawa, Ichiro; So, Hiromu; Sasatsu, Masanori

    2006-06-01

    The susceptibilities to antimicrobial agents 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 to antiseptic agents in MRSA isolates from patients with impetigo and SSSS were higher than those in MRSA isolates from patients with other diseases. The distribution of the qacA/B genes in MRSA strains isolated from patients with impetigo and SSSS (1.3%, 1/76) was remarkably lower than that in MRSA strains isolated from patients with other diseases (45.9%, 95/207). Epidemiologic typings of staphylococcal cassette chromosome mec (SCCmec) and pulsed-field gel electrophoresis (PFGE) showed that MRSA strains isolated from patients with impetigo and SSSS had type IV SCCmec (75/76), except for one strain, and 64.5% (49/76) of the strains had different PFGE types. In addition, the patterns of restriction digestion of all tested qacA/B plasmid in MRSA isolates having different PFGE types were identical. The results showed that a specific MRSA clone carrying qacA/B was not prevalent, but qacA/B was spread among health care-associated MRSA strains. Therefore, it was concluded that the lower distribution rate of qacA/B resulted in higher susceptibilities to cationic antiseptic agents in MRSA isolated from patients with impetigo and SSSS.

  19. Synthesis and Biological Evaluation of N- Pyrazolyl Derivatives and Pyrazolopyrimidine Bearing a Biologically Active Sulfonamide Moiety as Potential Antimicrobial Agent.

    PubMed

    Hafez, Hend N; El-Gazzar, Abdel-Rhman B A

    2016-08-31

    A series of novel pyrazole-5-carboxylate containing N-triazole derivatives 3,4; different heterocyclic amines 7a-b and 10a-b; pyrazolo[4,3-d]pyrimidine containing sulfa drugs 14a,b; and oxypyrazolo[4,3-d]pyrimidine derivatives 17, 19, 21 has been synthesized. The structure of the newly synthesized compounds was elucidated on the basis of analytical and spectral analyses. All compounds have been screened for their in vitro antimicrobial activity against three gram-positive and gram-negative bacteria as well as three fungi. The results revealed that compounds 14b and 17 had more potent antibacterial activity against all bacterial strains than reference drug Cefotaxime. Moreover compounds 4, 7b, and 12b showed excellent antifungal activities against Aspergillus niger and Candida albicans in low inhibitory concentrations but slightly less than the reference drug miconazole against Aspergillus flavus.

  20. Synthesis of chiral macrocyclic or linear pyridine carboxamides from pyridine-2,6-dicarbonyl dichloride as antimicrobial agents.

    PubMed

    Al-Salahi, Rashad A; Al-Omar, Mohamed A; Amr, Abd El-Galil E

    2010-09-20

    A series of chiral linear and macrocyclic bridged pyridines has been prepared starting from pyridine-2,6-dicarbonyl dichloride (2). The coupling of 1 with D-alanyl methyl ester gave 2,6-bis-D-alanyl pyridine methyl ester (3). Hydrazinolysis of 3 with hydrazine hydrate afforded bis-hydrazide 4. The latter was reacted with thiophene-2-carbaldehyde, phthalic anhydride or cyclohexanone to afford bis-carboxamide pyridine derivatives 5-7, respectively. Compound 4 was coupled with p-methoxy- or p-nitroaceto-phenone to yield compounds 8 and 9. In addition, 4 was reacted with 1,2,4,5-benzenetetra-carboxylic acid dianhydride or 1,4,5,8-naphthalenetetracarboxylic acid dianhydride to afford the macrocyclic octacarboxaamide pyridines 10 and 11. The detailed synthesis, spectroscopic data and antimicrobial screening for the synthesized compounds are reported.

  1. Design and characterization of short antimicrobial peptides using leucine zipper templates with selectivity towards microorganisms.

    PubMed

    Ahmad, Aqeel; Azmi, Sarfuddin; Srivastava, Saurabh; Kumar, Amit; Tripathi, Jitendra Kumar; Mishra, Nripendra N; Shukla, Praveen K; Ghosh, Jimut Kanti

    2014-11-01

    Design of antimicrobial peptides with selective activity towards microorganisms is an important step towards the development of new antimicrobial agents. Leucine zipper sequence has been implicated in cytotoxic activity of naturally occurring antimicrobial peptides; moreover, this motif has been utilized for the design of novel antimicrobial peptides with modulated cytotoxicity. To understand further the impact of substitution of amino acids at 'a' and/or 'd' position of a leucine zipper sequence of an antimicrobial peptides on its antimicrobial and cytotoxic properties four short peptides (14-residue) were designed on the basis of a leucine zipper sequence without or with replacement of leucine residues in its 'a' and 'd' positions with D-leucine or alanine or proline residue. The original short leucine zipper peptide (SLZP) and its D-leucine substituted analog, DLSA showed comparable activity against the tested Gram-positive and negative bacteria and the fungal strains. The alanine substituted analog (ASA) though showed appreciable activity against the tested bacteria, it showed to some extent lower activity against the tested fungi. However, the proline substituted analog (PSA) showed lower activity against the tested bacterial or fungal strains. Interestingly, DLSA, ASA and PSA showed significantly lower cytotoxicity than SLZP against both human red blood cells (hRBCs) and murine 3T3 cells. Cytotoxic and bactericidal properties of these peptides matched with peptide-induced damage/permeabilization of mammalian cells and bacteria or their mimetic lipid vesicles suggesting cell membrane could be the target of these peptides. As evidenced by tryptophan fluorescence and acrylamide quenching studies the peptides showed similarities either in interaction or in their localization within the bacterial membrane mimetic negatively charged lipid vesicles. Only SLZP showed localization inside the mammalian membrane mimetic zwitterionic lipid vesicles. The results show

  2. Efficient Synthesis and Biological Evaluation of a Novel Series of 1,5-Benzodiazepine Derivatives as Potential Antimicrobial Agents.

    PubMed

    An, Ying-Shuang; Hao, Zhen-Fang; Zhang, Xiu-Jun; Wang, Lan-Zhi

    2016-07-01

    A series of novel 1,5-benzodiazepine derivatives were rationally designed and synthesized following the principle of the superposition of bioactive substructures by the combination of 1,5-benzodiazepine, pyridine (phenyl), and an ester group. The structures of the target compounds were determined by (1) H NMR, (13) C NMR, MS, IR, and elemental analysis. All the synthesized compounds were evaluated for their antimicrobial activities in vitro against the fungi C. neoformans, C. neoformans clinical isolates (ATCC 32264), C. albicans (ATCC 10231), Gram-negative bacterium E. coli (ATCC 44752), and Gram-positive bacterium S. aureus (ATCC 25923). The results of the bioactive assay demonstrated that most of the tested compounds exhibited variable inhibitory effects on the growth of the tested microorganisms. All the active compounds showed better antifungal activity than antibacterial activity. Notably, compound 2b displayed the highest activity (MIC = 30 μg/mL) against C. neoformans and (MIC = 31 μg/mL) against C. neoformans clinical isolates. In addition, compound 2a also showed excellent activity against C. neoformans and C. neoformans clinical isolates with minimum inhibitory concentration of 35 and 36 μg/mL, respectively. Compounds 2a and 2b were further studied by evaluating their cytotoxicities, and the results showed that they have relatively low level cytotoxicity for BV2 and 293T cell. Preliminary structure-activity relationship study on three diverse sets (C-2, C-3, and C-8 positions) of 1,5-benzodiazepines was performed. The results revealed that the presence of a -CH3 group at the C-8 position had a positive effect on the inhibitory activity of these compounds. Additionally, the 2-pyridyl group at the C-2 position may be a pharmacophore and -COOC2 H5 at C-3 position is the best substituent for the maintenance of antimicrobial activities.

  3. Synthesis and biological evaluation of a new series of benzimidazole derivatives as antimicrobial, antiquorum-sensing and antitumor agents.

    PubMed

    El-Gohary, N S; Shaaban, M I

    2017-05-05

    New benzimidazole derivatives were synthesized and assessed for antimicrobial efficacy toward Escherichia coli, Bacillus cereus, Staphylococcus aureus, Candida albicans and Aspergillus fumigatus 293. Results indicated that compounds 3c and 3n have promising activity toward S. aureus, whereas 3i exhibited remarkable efficacy toward B. cereus. Moreover, compound 3c was proved to be the most active antifungal analog toward C. albicans. On the other hand, 3n displayed the highest activity against A. fumigatus 293. Antiquorum-sensing activity of the same compounds was also tested against Chromobacterium violacium ATCC 12472, whereas compounds 3c-f, 3i-k and 3m-o showed acceptable activity. In vitro antitumor testing of these compounds toward liver cancer (HepG2), colon cancer (HCT-116) and breast cancer (MCF-7) cell lines revealed that compound 3p has the highest potency against the three tested cell lines. Moreover, 3f, 3m and 3n displayed promising activity toward all tested cell lines. Compounds 3f, 3m, 3n and 3p were esteemed for in vivo antitumor activity against EAC cells. The active antimicrobial and antitumor analogs, 3a, 3c, 3f, 3i-k, 3m, 3n and 3p were assessed for DNA-binding affinity, and results indicated that 3c, 3f, 3i, 3k and 3n have strong DNA-binding affinity. The computational studies affirmed that almost all of the inspected compounds meet the optimal requirements for good absorption and oral bioavailability.

  4. Antimicrobial Peptides

    PubMed Central

    Bahar, Ali Adem; Ren, Dacheng

    2013-01-01

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

  5. Absorbent silver (I) antimicrobial fabrics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In recent years, silver in form of silver ions, has been gaining importance in the wound management as an effective broad-spectrum antimicrobial agent. Silver has a long history as an antimicrobial agent, especially in the treatment of wounds. Alginates and carboxymethyl (CM) cotton contain carboxyl...

  6. Clinical practice guideline for the use of antimicrobial agents in neutropenic patients with cancer: 2010 update by the infectious diseases society of america.

    PubMed

    Freifeld, Alison G; Bow, Eric J; Sepkowitz, Kent A; Boeckh, Michael J; Ito, James I; Mullen, Craig A; Raad, Issam I; Rolston, Kenneth V; Young, Jo-Anne H; Wingard, John R

    2011-02-15

    This document updates and expands the initial Infectious Diseases Society of America (IDSA) Fever and Neutropenia Guideline that was published in 1997 and first updated in 2002. It is intended as a guide for the use of antimicrobial agents in managing patients with cancer who experience chemotherapy-induced fever and neutropenia. Recent advances in antimicrobial drug development and technology, clinical trial results, and extensive clinical experience have informed the approaches and recommendations herein. Because the previous iteration of this guideline in 2002, we have a developed a clearer definition of which populations of patients with cancer may benefit most from antibiotic, antifungal, and antiviral prophylaxis. Furthermore, categorizing neutropenic patients as being at high risk or low risk for infection according to presenting signs and symptoms, underlying cancer, type of therapy, and medical comorbidities has become essential to the treatment algorithm. Risk stratification is a recommended starting point for managing patients with fever and neutropenia. In addition, earlier detection of invasive fungal infections has led to debate regarding optimal use of empirical or preemptive antifungal therapy, although algorithms are still evolving. What has not changed is the indication for immediate empirical antibiotic therapy. It remains true that all patients who present with fever and neutropenia should be treated swiftly and broadly with antibiotics to treat both gram-positive and gram-negative pathogens. Finally, we note that all Panel members are from institutions in the United States or Canada; thus, these guidelines were developed in the context of North American practices. Some recommendations may not be as applicable outside of North America, in areas where differences in available antibiotics, in the predominant pathogens, and/or in health care-associated economic conditions exist. Regardless of venue, clinical vigilance and immediate treatment are

  7. Clinical practice guideline for the use of antimicrobial agents in neutropenic patients with cancer: 2010 Update by the Infectious Diseases Society of America.

    PubMed

    Freifeld, Alison G; Bow, Eric J; Sepkowitz, Kent A; Boeckh, Michael J; Ito, James I; Mullen, Craig A; Raad, Issam I; Rolston, Kenneth V; Young, Jo-Anne H; Wingard, John R

    2011-02-15

    This document updates and expands the initial Infectious Diseases Society of America (IDSA) Fever and Neutropenia Guideline that was published in 1997 and first updated in 2002. It is intended as a guide for the use of antimicrobial agents in managing patients with cancer who experience chemotherapy-induced fever and neutropenia. Recent advances in antimicrobial drug development and technology, clinical trial results, and extensive clinical experience have informed the approaches and recommendations herein. Because the previous iteration of this guideline in 2002, we have a developed a clearer definition of which populations of patients with cancer may benefit most from antibiotic, antifungal, and antiviral prophylaxis. Furthermore, categorizing neutropenic patients as being at high risk or low risk for infection according to presenting signs and symptoms, underlying cancer, type of therapy, and medical comorbidities has become essential to the treatment algorithm. Risk stratification is a recommended starting point for managing patients with fever and neutropenia. In addition, earlier detection of invasive fungal infections has led to debate regarding optimal use of empirical or preemptive antifungal therapy, although algorithms are still evolving. What has not changed is the indication for immediate empirical antibiotic therapy. It remains true that all patients who present with fever and neutropenia should be treated swiftly and broadly with antibiotics to treat both gram-positive and gram-negative pathogens. Finally, we note that all Panel members are from institutions in the United States or Canada; thus, these guidelines were developed in the context of North American practices. Some recommendations may not be as applicable outside of North America, in areas where differences in available antibiotics, in the predominant pathogens, and/or in health care-associated economic conditions exist. Regardless of venue, clinical vigilance and immediate treatment are

  8. Antimicrobial susceptibility to levofloxacin and other antibacterial agents among common respiratory pathogens-a Brazilian perspective from the GLOBAL Surveillance Initiative 2001-2002.

    PubMed

    Mendes, C; Kiffer, C R V; Blosser-Middleton, R S; Jones, M E; Karlowsky, J A; Barth, A; Rossi, F; Andrade, S; Sader, H S; Thornsberry, C; Sahm, D F

    2004-06-01

    The GLOBAL (Global Landscape On Bactericidal Activity of Levofloxacin) Surveillance programme monitored antimicrobial susceptibility patterns of the key respiratory tract pathogens Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis collected in Brazil during 1997-1998, 1999-2000 and 2001-2002. Penicillin and azithromycin resistance among S. pneumoniae strains increased from 1997-1998, reaching 7.9% and 9.5%, respectively, in 2001-2002. Although decreasing by 4.9% since the previous study, trimethoprim-sulphamethoxazole resistance remained high at 33.7%. Concurrent resistance to penicillin, azithromycin and trimethoprim-sulphamethoxazole was seen in 2.9% of the S. pneumoniae isolates collected. Levofloxacin remained extremely active against S. pneumoniae, with 0.3% resistance reported in 1997-1998 and 0% resistance in 1999-2000 and 2001-2002. beta-Lactamase production in H. influenzae was > 10% in all three studies, with correspondingly high rates of ampicillin resistance. Trimethoprim-sulphamethoxazole was the least active agent tested against H. influenzae, with resistance rates of > 40% recorded in all three studies. All H. influenzae isolates were susceptible to cefuroxime, ceftriaxone, azithromycin and levofloxacin. Of the M. catarrhalis isolates, 98.0% in 1997-1998, 98.0% in 1999-2000 and 81.8% in 2001-2002 were beta-lactamase-positive. The continued high prevalence of antimicrobial resistance in Brazil underscores the importance of current surveillance initiatives. Levofloxacin, a fluoroquinolone prescribed widely for respiratory tract infections, continued to show potent activity against key respiratory pathogens.

  9. Alternatives to the use of antimicrobial agents in pig production: A multi-country expert-ranking of perceived effectiveness, feasibility and return on investment.

    PubMed

    Postma, Merel; Stärk, Katharina D C; Sjölund, Marie; Backhans, Annette; Beilage, Elisabeth Grosse; Lösken, Svenja; Belloc, Catherine; Collineau, Lucie; Iten, Denise; Visschers, Vivianne; Nielsen, Elisabeth O; Dewulf, Jeroen

    2015-03-01

    Nineteen alternatives to antimicrobial agents were ranked on perceived effectiveness, feasibility and return on investment (ROI) from 0 (not effective, not feasible, no ROI) to 10 (fully effective, completely feasible, maximum ROI) by 111 pig health experts from Belgium, Denmark, France, Germany, Sweden and Switzerland. The top 5 measures in terms of perceived effectiveness were (1) improved internal biosecurity, (2) improved external biosecurity, (3) improved climate/environmental conditions, (4) high health/Specific Pathogen Free/disease eradication and (5) increased vaccination. The top 5 measures in terms of perceived feasibility were (1) increased vaccination, (2) increased use of anti-inflammatory products, (3) improved water quality, (4) feed quality/optimization and (5) use of zinc/metals. The top 5 measures in terms of perceived ROI were (1) improved internal biosecurity, (2) zinc/metals, (3) diagnostics/action plan, (4) feed quality/optimization and (5) climate/environmental improvements. Univariate linear regression showed that veterinary practitioners rank internal biosecurity, vaccination, use of zinc/metals, feed quality optimization and climate/environmental on average highest, while researchers and professors focused more on increased use of diagnostics and action plans. Financial incentives/penalties ranked low in all countries. Belgian respondents ranked feed quality significantly lower compared to the German respondents while reduction of stocking density was ranked higher in Belgium compared to Denmark. Categorical Principal Component Analysis applied to the average ranking supported the finding that veterinary practitioners had a preference for more practical, common and already known alternatives. The results showed that improvements in biosecurity, increased use of vaccination, use of zinc/metals, feed quality improvement and regular diagnostic testing combined with a clear action plan were perceived to be the most promising alternatives to

  10. The phenotypic and genotypic characteristics of antibiotic resistance in Escherichia coli populations isolated from farm animals with different exposure to antimicrobial agents.

    PubMed

    Mazurek, Justyna; Pusz, Paweł; Bok, Ewa; Stosik, Michał; Baldy-Chudzik, Katarzyna

    2013-01-01

    The aim of the study was to determine the influence of the presence or the absence of antibiotic input on the emergence and maintenance of resistance in commensal bacteria from food producing animals. The research material constituted E. coli isolates from two animal species: swine at different age from one conventional pig farm with antibiotic input in young pigs and from beef and dairy cattle originated from organic breeding farm. The sensitivity to 16 antimicrobial agents was tested, and the presence of 15 resistance genes was examined. In E. coli from swine, the most prevalent resistance was resistance to streptomycin (88.3%), co-trimoxazole (78.8%), tetracycline (57.3%) ampicillin (49.3%) and doxycycline (44.9%) with multiple resistance in the majority. The most commonly observed resistance genes were: bla(TEM) (45.2%), tetA (35.8%), aadA1 (35.0%), sul3 (29.5%), dfrA1 (20.4%). Differences in phenotypes and genotypes of E. coli between young swine undergoing prevention program and the older ones without the antibiotic pressure occurred. A disparate resistance was found in E. coli from cattle: cephalothin (36.9%), cefuroxime (18.9%), doxycycline (8.2%), nitrofurantoin (7.7%), and concerned mainly dairy cows. Among isolates from cattle, multidrug resistance was outnumbered by resistance to one or two antibiotics and the only found gene markers were: bla(SHV), (3.4%), tetA (1.29%), bla(TEM) (0.43%) and tetC (0.43%). The presented outcomes provide evidence that antimicrobial pressure contributes to resistance development, and enteric microflora constitutes an essential reservoir of resistance genes.

  11. Implementation of a Prolonged Infusion Guideline for Time-Dependent Antimicrobial Agents at a Tertiary Academic Medical Center.

    PubMed

    Hohlfelder, Benjamin; Kubiak, David W; Degrado, Jeremy R; Reardon, David P; Szumita, Paul M

    Administration of time-dependent beta-lactam antibiotic as a prolonged infusion may maximize the pharmacodynamic target of time above the minimum inhibitory concentration. We describe the implementation of a prolonged infusion at a tertiary academic medical center, and a 1-year compliance analysis with the guideline. After performing a thorough literature search, a guideline was developed by members of the Department of Infectious Diseases and Department of Pharmacy. Approval and endorsement of the guideline was obtained by the Antimicrobial Subcommittee and Pharmacy and Therapeutics Committee. Physical champions were instrumental in the implementation of the guideline institution-wide. We then performed a 1-year retrospective analysis of guideline compliance from January 1, 2011 to December 31, 2011. Noncompliant administrations were obtained from smart infusion pumps. The total number of doses administered was taken from pharmacy information resources. In total, nearly 85,000 time-dependent doses were administered. Compliance with the prolonged infusion guideline was 89%. Rates of compliance did not significantly differ between medications (P = 0.555). Obtaining support from key stakeholders in collateral services and institutional leadership was vital for the success of this guideline. Compliance with the guideline 1 year after implementation was high. Implementation of a prolonged infusion guideline is feasible with institutional support and motivation.

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

    PubMed

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

    2014-12-01

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

  13. Resistance to the Antimicrobial Agent Fosmidomycin and an FR900098 Prodrug through Mutations in the Deoxyxylulose Phosphate Reductoisomerase Gene (dxr)

    PubMed Central

    Armstrong, Christopher M.; Meyers, David J.; Freel Meyers, Caren

    2015-01-01

    There is a pressing need for new antimicrobial therapies to combat globally important drug-resistant human pathogens, including Plasmodium falciparum malarial parasites, Mycobacterium tuberculosis, and Gram-negative bacteria, including Escherichia coli. These organisms all possess the essential methylerythritol phosphate (MEP) pathway of isoprenoid biosynthesis, which is not found in humans. The first dedicated enzyme of the MEP pathway, 1-deoxy-d-xylulose 5-phosphate reductoisomerase (Dxr), is inhibited by the phosphonic acid antibiotic fosmidomycin and its analogs, including the N-acetyl analog FR900098 and the phosphoryl analog fosfoxacin. In order to identify mutations in dxr that confer resistance to these drugs, a library of E. coli dxr mutants was screened at lethal fosmidomycin doses. The most resistant allele (with the S222T mutation) alters the fosmidomycin-binding site of Dxr. The expression of this resistant allele increases bacterial resistance to fosmidomycin and other fosmidomycin analogs by 10-fold. These observations confirm that the primary cellular target of fosmidomycin is Dxr. Furthermore, cell lines expressing Dxr-S222T will be a powerful tool to confirm the mechanisms of action of future fosmidomycin analogs. PMID:26124156

  14. Design, synthesis and biological evaluation of berberine-benzimidazole hybrids as new type of potentially DNA-targeting antimicrobial agents.

    PubMed

    Jeyakkumar, Ponmani; Zhang, Ling; Avula, Srinivasa Rao; Zhou, Cheng-He

    2016-10-21

    A series of novel berberine-benzimidazole derivatives were conveniently and efficiently synthesized and characterized by NMR, IR, MS and HRMS spectra. Most of the prepared compounds showed effective antimicrobial activities in contrast with clinical norfloxacin, chloromycin and fluconazole. Especially, compound 5d exhibited good anti-MRSA, anti-Escherichia coli, and anti-Salmonella typhi activity with low MIC values of 2-8 μg/mL, which were comparable or even superior to reference drugs. The preliminarily interactive investigation revealed that the most active compound 5d could effectively intercalate into DNA to form 5d-DNA complex and cleavage DNA by agarose gel electrophoresis experiments. It was also found that compound 5d was able to efficiently permeabilize the membranes of both Gram-positive (MRSA) and Gram-negative (E. coli DH52) bacteria. Experiments and molecular docking both showed that human serum albumin (HSA) could effectively transport compound 5d and hydrophobic interactions and hydrogen bonds play important roles in the association of compound 5d with HSA.

  15. Identification of penicillinase producing Neisseria gonorrhoeae in Chile during clinical and microbiological study of gonococcal susceptibility to antimicrobial agents.

    PubMed Central

    Garcia Moreno, J; Dillon, J R; Arroyave, R; Maldonado, A; Fich, F; Salvo, A; Villalobos, D; Vincent, P; Pauze, M

    1987-01-01

    The first penicillinase producing isolates of Neisseria gonorrhoeae (PPNG) identified in Chile were discovered during a clinical and microbiological study to compare the efficacy of penicillin (4.8 MIU aqueous procaine penicillin G plus 1 g oral probenecid) and tetracycline (1.5 g followed by 500 mg four times daily for four days) treatment regimens for acute uncomplicated gonorrhoea. Penicillin treatment was effective in 93.1% (282) of 303 patients, whereas tetracycline was effective in 98.3% (233) of 237 patients. Six of the penicillin treatment failures were attributable to PPNG strains. In all, 21 PPNG strains were identified during the study. They were genetically identical, having a wild type auxotype, a WII/III serotype (serovar Bajk), and carrying cryptic and transfer plasmids and an Asian type penicillinase producing plasmid. In addition, 674 non-PPNG isolates were tested for their susceptibility to eight antimicrobials. Over 95% were sensitivie to 1 mg/l of penicillin, ampicillin, cefotaxime, cefuroxime, and erythromycin, over 90% were sensitive to 1 mg/l of tetracycline and 2 mg/l of thiamphenicol, and all were sensitive to spectinomycin. Of 226 non-PPNG isolates characterised for plasmid content and auxotype, 90% (205) were either wild type or proline requiring, 67% (153) carried only the cryptic plasmid, and a further 31% (71) carried both cryptic and transfer plasmids. Unusually, three of four isolates lacking the cryptic plasmid carried only the transfer plasmid. Images PMID:3102348

  16. [Recommendations from MENSURA for selection of antimicrobial agents for susceptibility testing and criteria for the interpretation of antibiograms].

    PubMed

    2000-03-01

    This document includes the recommendations from the Spanish antibiogram committee (The MENSURA group, Mesa Española de Normalización de la Sensibilidad y Resistencia a los Antimicrobianos, under the auspices of the Sociedad Española de Quimioterapia and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica) for the selection of antimicrobials for susceptibility testing. Separate tables for each group of organism with proposed susceptibility and resistance breakpoints are updated and comparatively presented with those of other groups, such us NCCLS, CA-SFM and BSAC. The susceptibility breakpoint tends to identify the fully susceptible population, which probably lacks any specific resistance mechanism. The analysis of MIC distributions for different homogeneous populations (same species) is used to define breakpoints for susceptibility. The resistance breakpoint is based on pharmacological and clinical data obtained when the corresponding antibiotic is administered with a conventional schedule. The primary objective of the Spanish MENSURA group is to contribute to the international consensus on the establishment of breakpoints.

  17. Fate of flame retardants and the antimicrobial agent triclosan in planted and unplanted biosolid-amended soils.

    PubMed

    Davis, Elizabeth F; Gunsch, Claudia K; Stapleton, Heather M

    2015-05-01

    A comprehensive understanding of the fate of contaminant-laden biosolids is needed to fully evaluate the environmental impacts of biosolid land application. The present study examined the fate of several flame retardants and triclosan in biosolid-amended soil in a 90-d greenhouse experiment. Objectives included evaluating the persistence of these compounds in soil, their phytoaccumulation potential by alfalfa (Medicago sativa), and potential degradation reactions. Concentrations of the polybrominated diphenyl ether (PBDE) congeners BDE-47 and BDE-209 and the antimicrobial triclosan declined significantly over time in biosolid-amended soil planted with alfalfa and then reached a steady state by day 28. In contrast, no significant losses of those analytes were observed from soil in nonvegetated pots. The amount of an analyte lost from vegetated soil ranged from 43% for the flame retardant di(2-ethylhexyl)-2,3,4,5-tetrabromophthalate to 61% for triclosan and was significantly and negatively related to the log octanol-water partition coefficient. Alfalfa roots and shoots were monitored for the compounds, but no clear evidence of phytoaccumulation was observed. Methyl triclosan formation was observed in the biosolid-amended soils during the study period, indicating in situ biotransformation of triclosan. The present study demonstrates that, although they are highly recalcitrant, PBDEs, selected alternate brominated flame retardants, and triclosan are capable of undergoing dissipation from biosolid-amended soils in the presence of plants.

  18. Design, synthesis and molecular docking of salicylic acid derivatives containing metronidazole as a new class of antimicrobial agents.

    PubMed

    Guo, Zhi-Hua; Yin, Yong; Wang, Cong; Wang, Peng-Fei; Zhang, Xing-Tao; Wang, Zhong-Chang; Zhu, Hai-Liang

    2015-09-15

    A series of novel salicylic acid derivatives containing metronidazole as Staphylococcus aureus Tyrosyl-tRNA synthetase (TyrRS) inhibitors have been synthesized and evaluated their biology activities as potential antibacterial agents. Among these compounds, compound 5r exhibited the most potent antibacterial activity against Gram-positive (S. aureus ATCC 6538 and Bacillus subtilis ATCC 6633) and Gram-negative (Escherichia coli ATCC 35218 and Pseudomonas aeruginosa ATCC 13525) with MICs of 0.39-1.57 μg/mL and showed the most potent S. aureus Tyrosyl-tRNA synthetase inhibitory with 2.3 μM. Docking simulation was performed to insert compound 5r into the crystal structure of S. aureus Tyrosyl-tRNA synthetase active site to determine the probable binding model. These results suggested that compound 5r may be a promising antibacterial agent.

  19. The importance of expressing antimicrobial agents on water basis in growth/no growth interface models: a case study for Zygosaccharomyces bailii.

    PubMed

    Dang, T D T; Vermeulen, A; Mertens, L; Geeraerd, A H; Van Impe, J F; Devlieghere, F

    2011-01-31

    In a previous study on Zygosaccharomyces bailii, three growth/no growth models have been developed, predicting growth probability of the yeast at different conditions typical for acidified foods (Dang, T.D.T., Mertens, L., Vermeulen, A., Geeraerd, A.H., Van Impe, J.F., Debevere, J., Devlieghere, F., 2010. Modeling the growth/no growth boundary of Z. bailii in acidic conditions: A contribution to the alternative method to preserve foods without using chemical preservatives. International Journal of Food Microbiology 137, 1-12). In these broth-based models, the variables were pH, water activity and acetic acid, with acetic acid concentration expressed in volume % on the total culture medium (i.e., broth). To continue the previous study, validation experiments were performed for 15 selected combinations of intrinsic factors to assess the performance of the model at 22°C (60days) in a real food product (ketchup). Although the majority of experimental results were consistent, some remarkable deviations between prediction and validation were observed, e.g., Z. bailii growth occurred in conditions where almost no growth had been predicted. A thorough investigation revealed that the difference between two ways of expressing acetic acid concentration (i.e., on broth basis and on water basis) is rather significant, particularly for media containing high amounts of dry matter. Consequently, the use of broth-based concentrations in the models was not appropriate. Three models with acetic acid concentration expressed on water basis were established and it was observed that predictions by these models well matched the validation results; therefore a "systematic error" in broth-based models was recognized. In practice, quantities of antimicrobial agents are often calculated based on the water content of food products. Hence, to assure reliable predictions and facilitate the application of models (developed from lab media with high dry matter contents), it is important to express

  20. Activity of telavancin and comparator antimicrobial agents tested against Staphylococcus spp. isolated from hospitalised patients in Europe (2007-2008).

    PubMed

    Mendes, Rodrigo E; Sader, Helio S; Jones, Ronald N

    2010-10-01

    The activity of telavancin was evaluated against Staphylococcus spp. collected from European hospitals as part of an international surveillance study (2007-2008). A total of 7534 staphylococcal clinical isolates [5726 Staphylococcus aureus and 1808 coagulase-negative staphylococci (CoNS)] were included. Isolates were tested for susceptibility according to reference methods and minimum inhibitory concentration (MIC) values were interpreted based on Clinical and Laboratory Standards Institute (CLSI) 2010 and European Committee on Antimicrobial Susceptibility Testing (EUCAST) 2009 criteria. Telavancin breakpoints approved by the US Food and Drug Administration (FDA) were applied. Telavancin activity was evaluated against meticillin-resistant S. aureus (MRSA) displaying several antibiogram resistance patterns, including multidrug-resistant isolates. Telavancin was active against S. aureus [MIC(50/90) values (MICs for 50% and 90% of the isolates, respectively)=0.12/0.25mg/L; 100.0% susceptible] and CoNS (MIC(50/90)=0.12/0.25mg/L), inhibiting all isolates at < or =0.5mg/L. Similar results were observed when S. aureus were stratified by year or country of origin (MIC(50/90)=0.12/0.25mg/L). When MRSA isolates were clustered according to 48 different resistance patterns, telavancin showed consistent MIC(90) values (0.25mg/L) regardless of multidrug resistance. Amongst CoNS, telavancin was slightly more active against Staphylococcus capitis, Staphylococcus epidermidis, Staphylococcus hominis, Staphylococcus lugdunensis and Staphylococcus xylosus (MIC(50)=0.12 mg/L) compared with Staphylococcus haemolyticus, Staphylococcus saprophyticus and Staphylococcus warneri (MIC(50)=0.25mg/L). Overall, telavancin exhibited MIC(90) results two- to eight-fold lower than comparators (daptomycin, quinupristin/dalfopristin, vancomycin and linezolid). Based upon MIC(90) values, telavancin demonstrated potent in vitro activity against a contemporary (2007-2008) collection of Staphylococcus spp

  1. T4-like phage Bp7, a potential antimicrobial agent for controlling drug-resistant Escherichia coli in chickens.

    PubMed

    Zhang, Can; Li, Wenli; Liu, Wenhua; Zou, Ling; Yan, Chen; Lu, Kai; Ren, Huiying

    2013-09-01

    Chicken-pathogenic Escherichia coli is severely endangering the poultry industry in China and worldwide, and antibiotic therapy is facing an increasing problem of antibiotic resistance. Bacteriophages can kill bacteria with no known activity in human or animal cells, making them an attractive alternative to antibiotics. In this study, we present the characteristics of a novel virulent bacteriophage, Bp7, specifically infecting pathogenic multidrug-resistant E. coli. Phage Bp7 was isolated from chicken feces. Bp7 belongs to the family Myoviridae, possessing an elongated icosahedral head and contractile sheathed tail. It has a 168-kb double-stranded DNA genome. For larger yields, its optimal multiplicity of infection (MOI) to infect E. coli was about 0.001. The latent period was 10 to 15 min, and the burst size was 90 PFU/infected cell. It was stable both at pH 5.0 to 10.0 and at 40°C or 50°C for at least 1 h. Bp7 could infect 46% of pathogenic clinical E. coli strains. Bp7 harbored 791 open reading frames (ORFs) and 263 possible genes. Among the 263 genes, 199 possessed amino acid sequence identities with ORFs of phage T4, 62 had identities with other T4-like phages, and only one lacked any database match. The genome of Bp7 manifested obvious division and rearrangement compared to phages T4, JS98, and IME08. Bp7 is a new member of the "T4-like" genus, family Myoviridae. Its wide host range, strong cell-killing activity, and high stability to pH make it an alternative to antimicrobials for controlling drug-resistant E. coli in chickens.

  2. Evaluation of various soaking agents as a novel tool for pesticide residues mitigation from cauliflower (Brassica oleracea var. botrytis).

    PubMed

    Abdullah; Randhawa, Muhammad Atif; Asghar, Ali; Pasha, Imran; Usman, Rabia; Shamoon, Muhammad; Bhatti, Muhammad Arslan; Irshad, Muhammad Asim; Ahmad, Naveed

    2016-08-01

    The increasing use of pesticides for boosting the yield of agricultural crops also impart toxic residues which ultimately extend to numerous physiological disorders upon consumption. The present study was designed as an effort to assess the reduction potential of various chemical solutions and to minimize the pesticide residues in cauliflower (Brassica oleracea var. botrytis). The samples were soaked in various solutions along with tap water to mitigate pesticide residues. Afterwards, the extracted supernatant was passed through column containing anhydrous sodium sulfate trailed by activated carbon for clean-up. Eluents were first evaporated and then completely dried under gentle stream of Nitrogen. Finally, the residues were determined using gas chromatography equipped with electron capture detector (GC-ECD). Results revealed the highest reduction of endosulfan, bifenthrin and cypermethrin residues with acetic acid (10 %) was 1.133 ± 0.007 (41 %), 0.870 ± 0.022 (60 %) and 0.403 ± 0.003 (75 %), respectively among the tested solutions. However, simple tap water treatment also resulted in 0.990 ± 0.02 (12 %), 1.323 ± 0.015 (14 %) and 1.274 ± 0.002 (21 %) elimination of endosulfan, bifenthrin and cypermethrin residues, respectively. Moreover, among various solutions, acetic acid depicted maximum reduction potential followed by citric acid, hydrogen peroxide, sodium chloride and sodium carbonate solutions. The percent reduction by various solutions ranged from 12 to 41, 14 to 60 and 21 to 75 % for the elimination of endosulfan, bifenthrin and cypermethrin residues, respectively.

  3. Structural basis of a temporin 1b analogue antimicrobial activity against Gram negative bacteria determined by CD and NMR techniques in cellular environment.

    PubMed

    Malgieri, Gaetano; Avitabile, Concetta; Palmieri, Maddalena; D'Andrea, Luca Domenico; Isernia, Carla; Romanelli, Alessandra; Fattorusso, Roberto

    2015-04-17

    We here report an original approach to elucidate mechanisms of action of antimicrobial peptides and derive crucial structural requirements for the design of novel therapeutic agents. The high resolution structure of TB_KKG6A, an antimicrobial peptide designed to amplify the spectrum of action of Temporin B, bound to E. coli is here determined by means of CD and NMR methodologies. We have also defined, through STD analysis, the residues in closer proximity to the bacterial membrane.

  4. Efficacy of Lysophosphatidylcholine in Combination with Antimicrobial Agents against Acinetobacter baumannii in Experimental Murine Peritoneal Sepsis and Pneumonia Models

    PubMed Central

    Parra Millán, R.; Jiménez Mejías, M. E.; Sánchez Encinales, V.; Ayerbe Algaba, R.; Gutiérrez Valencia, A.; Pachón Ibáñez, M. E.; Díaz, C.; Pérez del Palacio, J.; López Cortés, L. F.; Smani, Y.

    2016-01-01

    Immune response stimulation to prevent infection progression may be an adjuvant to antimicrobial treatment. Lysophosphatidylcholine (LPC) is an immunomodulator involved in immune cell recruitment and activation. In this study, we aimed to evaluate the efficacy of LPC in combination with colistin, tigecycline, or imipenem in experimental murine models of peritoneal sepsis and pneumonia. We used Acinetobacter baumannii strain Ab9, which is susceptible to colistin, tigecycline, and imipenem, and multidrug-resistant strain Ab186, which is susceptible to colistin and resistant to tigecycline and imipenem. Pharmacokinetic and pharmacodynamic parameters for colistin, tigecycline, and imipenem and the 100% minimal lethal dose (MLD100) were determined for both strains. The therapeutic efficacies of LPC, colistin (60 mg/kg of body weight/day), tigecycline (10 mg/kg/day), and imipenem (180 mg/kg/day), alone or in combination, were assessed against Ab9 and Ab186 at the MLD100 in murine peritoneal sepsis and pneumonia models. The levels of pro- and anti-inflammatory cytokines, i.e., tumor necrosis factor alpha (TNF-α) and interleukin-10 (IL-10), were determined by enzyme-linked immunosorbent assay (ELISA) for the same experimental models after inoculating mice with the MLD of both strains. LPC in combination with colistin, tigecycline, or imipenem markedly enhanced the bacterial clearance of Ab9 and Ab186 from the spleen and lungs and reduced bacteremia and mouse mortality rates (P < 0.05) compared with those for colistin, tigecycline, and imipenem monotherapies. Moreover, at 4 h post-bacterial infection, Ab9 induced higher TNF-α and lower IL-10 levels than those with Ab186 (4 μg/ml versus 3 μg/ml [P < 0.05] and 2 μg/ml versus 3.4 μg/ml [P < 0.05], respectively). LPC treatment combined with colistin, tigecycline, or imipenem modestly reduced the severity of infection by A. baumannii strains with different resistance phenotypes compared to LPC monotherapy in both

  5. Combating Antimicrobial Resistance in Foodborne Microorganisms.

    PubMed

    Lai, Edward P C; Iqbal, Zafar; Avis, Tyler J

    2016-02-01

    This review addresses an important public health hazard affecting food safety. Antimicrobial agents are used in foods to reduce or eliminate microorganisms that cause disease. Many traditional organic compounds, novel synthetic organic agents, natural products, peptides, and proteins have been extensively studied for their effectiveness as antimicrobial agents against foodborne Campylobacter spp., Escherichia coli, Listeria spp. and Salmonella. However, antimicrobial resistance can develop in microorganisms, enhancing their ability to withstand the inhibiting or killing action of antimicrobial agents. Knowledge gaps still exist with regard to the actual chemical and microbiological mechanisms that must be identified to facilitate the search for new antimicrobial agents. Technical implementation of antimicrobial active packing films and coatings against target microorganisms must also be improved for extended product shelf life. Recent advances in antimicrobial susceptibility testing can provide researchers with new momentum to pursue their quest for a resistance panacea.

  6. Zinc-Substituted Myoglobin Is a Naturally Occurring Photo-antimicrobial Agent with Potential Applications in Food Decontamination.

    PubMed

    Delcanale, Pietro; Montali, Chiara; Rodríguez-Amigo, Beatriz; Abbruzzetti, Stefania; Bruno, Stefano; Bianchini, Paolo; Diaspro, Alberto; Agut, Montserrat; Nonell, Santi; Viappiani, Cristiano

    2016-11-16

    Zinc-substituted myoglobin (ZnMb) is a naturally occurring photosensitizer that generates singlet oxygen with a high quantum yield. Using a combination of photophysical and fluorescence imaging techniques, we demonstrate the interaction of ZnMb with Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. An efficient antibacterial action against S. aureus was observed, with a reduction up to 99.9999% in the number of colony-forming units, whereas no sizable effect was detected against E. coli. Because ZnMb is known to form during the maturation of additive-free not-cooked cured ham, the use of this protein as a built-in photodynamic agent may constitute a viable method for the decontamination of these food products from Gram-positive bacteria.

  7. Stir-bar-sorptive extraction and ultra-high-performance liquid chromatography-tandem mass spectrometry for simultaneous analysis of UV filters and antimicrobial agents in water samples.

    PubMed

    Pedrouzo, Marta; Borrull, Francesc; Marcé, Rosa Maria; Pocurull, Eva

    2010-08-01

    Stir-bar-sorptive extraction (SBSE) with liquid desorption (LD) and ultra-high-performance liquid chromatography-electrospray ionization triple-quadrupole tandem mass spectrometry (UHPLC-(ESI)MS-MS) were used for analysis of six personal care products in environmental water: four UV filters (2,2-dihydroxy-4-methoxybenzophenone, benzophenone-3, octocrylene, and octyldimethyl-p-aminobenzoic acid) and two antimicrobial agents (triclocarban and triclosan). Experimental conditions that affect SBSE-LD sorption efficiency (extraction time and temperature, sample pH, and ionic strength) and desorption efficiency (solvent, temperature, and time) were optimized. The method proved to be sensitive--a 50-mL sample was used to determine these compounds in environmental waters at trace levels. The detection limits of the analytical method were 2.5 ng L(-1) for river water and 5-10 ng L(-1) for effluent and influent sewage water. In river waters, benzophenone-3 was found at levels from 6 ng L(-1) to 28 ng L(-1) and triclosan at levels

  8. Antimicrobial activity of ceftazidime-avibactam and comparator agents when tested against bacterial isolates causing infection in cancer patients (2013-2014).

    PubMed

    Sader, Helio S; Castanheira, Mariana; Jones, Ronald N; Flamm, Robert K

    2017-03-01

    We evaluated the antimicrobial susceptibility of 623 Gram-negative organisms causing infection in patients with cancer in 52 United States hospitals (2013-2014) as part of the International Network for Optimal Resistance Monitoring (INFORM) program. Isolates were tested for susceptibility by broth microdilution method. β-lactamase encoding genes were evaluated for all Escherichia coli and Klebsiella spp. with an extended-spectrum β-lactamase (ESBL) phenotype by microarray-based assay. ESBL-phenotype was observed among 17.3 and 9.9% of E. coli and Klebsiella pneumoniae, respectively; and 25.0% of Enterobacter cloacae were ceftazidime-non-susceptible. All Enterobacteriaceae (n=486) were susceptible to ceftazidime-avibactam (MIC50/90, 0.12/0.25μg/mL) with the highest MIC value at 1μg/mL. Meropenem was active against Enterobacteriaceae overall (MIC50/90, ≤0.06/≤0.06μg/mL; 99.6% susceptible); but showed more limited activity against Klebsiella spp. with an ESBL-phenotype (84.6% susceptible) and multidrug-resistant Enterobacteriaceae (93.3% susceptible). The most active agents tested against Pseudomonas aeruginosa were colistin (100.0% susceptible), amikacin (97.7% susceptible) and ceftazidime-avibactam (96.6% susceptible).

  9. Comparative in vitro activities of azithromycin, Bay y 3118, levofloxacin, sparfloxacin, and 11 other oral antimicrobial agents against 194 aerobic and anaerobic bite wound isolates.

    PubMed Central

    Goldstein, E J; Nesbit, C A; Citron, D M

    1995-01-01

    The activities of sparfloxacin, levofloxacin, Bay y 3118, azithromycin, cefprozil, loracarbef, and nine other oral antimicrobial agents against 194 aerobic and anaerobic clinical bite wound isolates were determined by the agar dilution method. Sparfloxacin, levofloxacin, and Bay y 3118 were active against all aerobic isolates (MICs at which 90% of the isolates are inhibited [MIC90], < or = 1.0 microgram/ml for sparfloxacin and levofloxacin and 0.1 microgram/ml for Bay y 3118) and many anaerobic isolates, with the exception of the fusobacteria. Azithromycin was more active than erythromycin by 1 to 2 dilutions against many aerobes, including Pasteurella multocida and Eikenella corrodens, and by 2 to 4 dilutions against anaerobic isolates. Cefprozil was more active (MIC90, < or = 1 microgram/ml) than loracarbef (MIC90, < or = 4 micrograms/ml) against aerobic gram-positive isolates, but both had poor activity (MIC90, > or = 16 micrograms/ml) against peptostreptococci. Both cefprozil and loracarbef had MIC90s of < or = 0.5 micrograms/ml against P. multocida. PMID:7625795

  10. Ziziphora clinopodioides Essential Oil and Nisin as Potential Antimicrobial Agents against Escherichia coli O157:H7 in Doogh (Iranian Yoghurt Drink)

    PubMed Central

    Shahbazi, Yasser

    2015-01-01

    The aim of the present study was to evaluate the effects of Ziziphora clinopodioides essential oil (0.1 and 0.2%) and nisin (250 and 500 IU/mL) separately and in combination on survival of Escherichia coli O157:H7 inoculated in Doogh (Iranian yoghurt drink) during storage under refrigerated temperature (4 ± 1°C) for 9 days. Viability of Lactobacillus casei at different concentrations of Z. clinopodioides essential oil (0.1 and 0.2%) in Doogh was also examined. The major components were carvacrol (64.22%), thymol (19.22%), γ-terpinene (4.63%), and p-cymene (4.86%). There was no significant difference (p > 0.05) between samples treated with nisin and those of untreated samples. Samples treated with both concentrations of the essential oil (0.1 and 0.2%) showed populations of E. coli O157:H7 significantly (p < 0.05) lower than those of untreated samples. The essential oil of Z. clinopodioides in combination with nisin had a potential synergistic effect against E. coli O157:H7 in Doogh samples after 5 days. The count of L. casei was not inhibited by different concentrations of the Z. clinopodioides essential oil. It is concluded that the leaf essential oil of Z. clinopodioides in combination with nisin can be applied as alternative antimicrobial agents in Doogh to inhibit the growth of E. coli O157:H7. PMID:26783466

  11. Evaluation of the synergistic potential of vancomycin combined with other antimicrobial agents against methicillin-resistant Staphylococcus aureus and coagulase-negative Staphylococcus spp strains.

    PubMed

    Silva, Lívia Viganor da; Araújo, Manuela Tedesco; Santos, Kátia Regina Netto dos; Nunes, Ana Paula Ferreira

    2011-02-01

    Methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative Staphylococcus spp (CNS) are the most common pathogens that cause serious long term infections in patients. Despite the existence of new antimicrobial agents, such as linezolid, vancomycin (VAN) remains the standard therapy for the treatment of infections caused by these multidrug-resistant strains. However, the use of VAN has been associated with a high frequency of therapeutic failures in some clinical scenarios, mainly with decreasing concentration of VAN. This work aims to evaluate the synergic potential of VAN plus sulfamethoxazole/trimethoprim (SXT), VAN plus rifampin (RIF) and VAN plus imipenem (IPM) in sub-minimum inhibitory concentrations against 22 clinical strains of MRSA and CNS. The checkerboard method showed synergism of VAN/RIF and VAN/SXT against two and three of the 22 strains, respectively. The combination of VAN with IPM showed synergistic effects against 21 out of 22 strains by the E-test method. Four strains were analyzed by the time-kill curve method and synergistic activity was observed with VAN/SXT, VAN/RIF and especially VAN/IPM in sub-inhibitory concentrations. It would be interesting to determine if synergy occurs in vivo. Evidence of in vivo synergy could lead to a reduction of the standard VAN dosage or treatment time.

  12. Mechanism of action and specificity of antimicrobial peptides designed based on buforin IIb.

    PubMed

    Jang, Su A; Kim, Hyun; Lee, Ju Young; Shin, Ju Ri; Kim, Da Jung; Cho, Ju Hyun; Kim, Sun Chang

    2012-04-01

    Buforin IIb-a synthetic analog of buforin II that contains a proline hinge between the two α-helices and a model α-helical sequence at the C-terminus (3× RLLR)-is a potent cell-penetrating antimicrobial peptide. To develop novel antimicrobial peptides with enhanced activities and specificity/therapeutic index, we designed several analogs (Buf III analogs) by substitutions of amino acids in the proline hinge region and two α-helices of buforin IIb, and examined their antimicrobial activity and mechanism of action. The substitution of hydrophobic residues ([F(6)] and [V(8)]) in the proline hinge region with other hydrophobic residues ([W(6)] and [I(8)]) did not affect antimicrobial activity, while the substitution of the first four amino acids RAGL with a model α-helical sequence increased the antimicrobial activity up to 2-fold. Like buforin IIb, Buf III analogs penetrated the bacterial cell membranes without significantly permeabilizing them and were accumulated inside Escherichia coli. Buf III analogs were shown to bind DNA in vitro and the DNA binding affinity of the peptides correlated linearly with their antimicrobial potency. Among the Buf III analogs, the therapeutic index of Buf IIIb and IIIc (RVVRQWPIG[RVVR](3) and KLLKQWPIG[KLLK](3), respectively) were improved 7-fold compared to that of buforin IIb. These results indicate that Buf III analogs appear to be promising candidates for future development as novel antimicrobial agents.

  13. Antimicrobial prophylaxis in adults.

    PubMed

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

    2011-07-01

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

  14. Alternative Antimicrobial Approach: Nano-Antimicrobial Materials

    PubMed Central

    Beyth, Nurit; Houri-Haddad, Yael; Domb, Avi; Khan, Wahid; Hazan, Ronen

    2015-01-01

    Despite numerous existing potent antibiotics and other antimicrobial means, bacterial infections are still a major cause of morbidity and mortality. Moreover, the need to develop additional bactericidal means has significantly increased due to the growing concern regarding multidrug-resistant bacterial strains and biofilm associated infections. Consequently, attention has been especially devoted to new and emerging nanoparticle-based materials in the field of antimicrobial chemotherapy. The present review discusses the activities of nanoparticles as an antimicrobial means, their mode of action, nanoparticle effect on drug-resistant bacteria, and the risks attendant on their use as antibacterial agents. Factors contributing to nanoparticle performance in the clinical setting, their unique properties, and mechanism of action as antibacterial agents are discussed in detail. PMID:25861355

  15. 40 CFR 158.2290 - Residue chemistry.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Residue chemistry. 158.2290 Section... REQUIREMENTS FOR PESTICIDES Antimicrobial Pesticide Data Requirements § 158.2290 Residue chemistry. (a) General... determine the residue chemistry data requirements for antimicrobial pesticide products. Notes that apply...

  16. Donor testing and risk: current prevalence, incidence, and residual risk of transfusion-transmissible agents in US allogeneic donations.

    PubMed

    Zou, Shimian; Stramer, Susan L; Dodd, Roger Y

    2012-04-01

    Over the past 20 years, there has been a major increase in the safety of the blood supply, as demonstrated by declining rates of posttransfusion infection and reductions in estimated residual risk for such infections. Reliable estimates of residual risk have been possible within the American Red Cross system because of the availability of a large amount of reliable and consistent data on donations and infectious disease testing results. Among allogeneic blood donations, the prevalence rates of infection markers for hepatitis C virus (HCV) and hepatitis B virus have decreased over time, although rates for markers of human immunodeficiency virus (HIV) and human T-cell lymphotropic virus did not. The incidence (/100 000 person-years) of HIV and HCV among repeat donors showed apparent increases from 1.55 and 1.89 in 2000 through 2001 to 2.16 and 2.98 in 2007 through 2008. These observed fluctuations confirm the need for continuous monitoring and evaluation. The residual risk of HIV, HCV, and human T-cell lymphotropic virus among all allogeneic donations is currently below 1 per 1 million donations, and that of hepatitis B surface antigen is close to 1 per 300 000 donations.

  17. Ethephon As a Potential Abscission Agent for Table Grapes: Effects on Pre-Harvest Abscission, Fruit Quality, and Residue

    PubMed Central

    Ferrara, Giuseppe; Mazzeo, Andrea; Matarrese, Angela M. S.; Pacucci, Carmela; Trani, Antonio; Fidelibus, Matthew W.; Gambacorta, Giuseppe

    2016-01-01

    Some plant growth regulators, including ethephon, can stimulate abscission of mature grape berries. The stimulation of grape berry abscission reduces fruit detachment force (FDF) and promotes the development of a dry stem scar, both of which could facilitate the production of high quality stemless fresh-cut table grapes. The objective of this research was to determine how two potential abscission treatments, 1445 and 2890 mg/L ethephon, affected FDF, pre-harvest abscission, fruit quality, and ethephon residue of Thompson Seedless and Crimson Seedless grapes. Both ethephon treatments strongly induced abscission of Thompson Seedless berries causing >90% pre-harvest abscission. Lower ethephon rates, a shorter post-harvest interval, or berry retention systems such as nets, would be needed to prevent excessive pre-harvest losses. The treatments also slightly affected Thompson Seedless berry skin color, with treated fruit being darker, less uniform in color, and with a more yellow hue than non-treated fruit. Ethephon residues on Thompson Seedless grapes treated with the lower concentration of ethephon were below legal limits at harvest. Ethephon treatments also promoted abscission of Crimson Seedless berries, but pre-harvest abscission was much lower (≅49%) in Crimson Seedless compared to Thompson Seedless. Treated fruits were slightly darker than non-treated fruits, but ethephon did not affect SSC, acidity, or firmness of Crimson Seedless, and ethephon residues were below legal limits. PMID:27303407

  18. Model Membrane and Cell Studies of Antimicrobial Activity of Melittin Analogues.

    PubMed

    Jamasbi, Elaheh; Mularski, Anna; Separovic, Frances

    2016-01-01

    Melittin is a 26 residue peptide and the major component of bee (Apis mellifera) venom. Although melittin has both anticancer and antimicrobial properties, utilization has been limited due to its high lytic activity against eukaryotic cells. The mechanism of this lytic activity remains unclear but several mechanisms have been proposed, including pore formation or a detergent like mechanism, which result in lysis of cell membranes. Several analogues of melittin have been synthesized to further understand the role of specific residues in its antimicrobial and lytic activity. Melittin analogues that have a proline residue substituted for an alanine, lysine or cysteine have been studied with both model membrane systems and living cells. These studies have revealed that the proline residue plays a critical role in antimicrobial activity and cytotoxicity. Analogues lacking the proline residue and dimers of these analogues displayed decreased cytotoxicity and minimum inhibition concentrations. Several mutant studies have shown that, when key substitutions are made, the resultant peptides have more activity in terms of pore formation than the native melittin. Designing analogues that retain antimicrobial and anticancer activity while minimizing haemolytic activity will be a promising way to utilize melittin as a potential therapeutic agent.

  19. Use of kidney inhibition swab test to evaluate antimicrobial residues in pork kidney from a market survey in Fargo, North Dakota

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: The USDA-Food Safety and Inspection Service (FSIS) recently changed the on-site antimicrobial screening method to the Kidney Inhibition Swab (KIS™) test to be used at all livestock slaughter establishments. Although the newly adapted screening method can detect different classes of an...

  20. Use of Antimicrobials during Pregnancy

    PubMed Central

    Nicolle, L.E.

    1987-01-01

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

  1. Antimicrobial Stewardship

    PubMed Central

    Doron, Shira; Davidson, Lisa E.

    2011-01-01

    Antimicrobial resistance is increasing; however, antimicrobial drug development is slowing. Now more than ever before, antimicrobial stewardship is of the utmost importance as a way to optimize the use of antimicrobials to prevent the development of resistance and improve patient outcomes. This review describes the why, what, who, how, when, and where of antimicrobial stewardship. Techniques of stewardship are summarized, and a plan for implementation of a stewardship program is outlined. PMID:22033257

  2. Uses of antimicrobial genes from microbial genome

    DOEpatents

    Sorek, Rotem; Rubin, Edward M.

    2013-08-20

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

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

    PubMed Central

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

    2011-01-01

    displayed a very low cytotoxicity on this cell line (5 to 10 times lower than cisplatin) and on normal primary cells derived from C57B6 mouse muscle explants, which may make them promising candidates as potential antimicrobial agents and safer catalysts due to low toxicity in human and other mammalian tissues. PMID:25134773

  4. Editorial of the Special Issue Antimicrobial Polymers

    PubMed Central

    Piozzi, Antonella; Francolini, Iolanda

    2013-01-01

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

  5. Three new antimicrobial peptides from the scorpion Pandinus imperator.

    PubMed

    Zeng, Xian-Chun; Zhou, Lingli; Shi, Wanxia; Luo, Xuesong; Zhang, Lei; Nie, Yao; Wang, Jinwei; Wu, Shifen; Cao, Bin; Cao, Hanjun

    2013-07-01

    Three novel cysteine-free venom peptides, which were referred to as Pantinin-1, Pantinin-2 and Pantinin-3, respectively, have been identified from the scorpion Pandinus imperator by cDNA cloning strategy. The precursor of each peptide consists of a signal peptide, a mature peptide with no disulfide bridges, and an acidic propeptide with a typical processing signal. Each of the three peptides is an α-helical, cationic and amphipathic molecule with 13 or 14 amino acid residues. Their amino acid sequences are homologous to those of some 13-mer antimicrobial peptides isolated from scorpions. Antimicrobial assay showed that all the three peptides possess relatively strong activities against Gram-positive bacteria and a fungus, but have very weak antimicrobial activities against Gram-negative bacteria. Toxicity assay showed that the three peptides exhibit very low or mild hemolytic activities against human red blood cells. It is interesting to see that Pantinin-3 is able to potently inhibit the growth of vancomycin-resistant Enterococcus (VRE) S13, a pathogen that can cause a number of human infections; this suggests that Pantinin-3 has great potential to be applied in the treatment of VRE infections. Our findings gain new insights into the structure/function relationships of the small linear cationic antimicrobial peptides from scorpions, and provide new templates for designing of antimicrobial agents targeting antibiotic-resistant pathogenic bacteria.

  6. Antimicrobial drug resistance.

    PubMed

    Martinez, Marilyn; Silley, Peter

    2010-01-01

    This chapter provides an overview of our current understanding of the mechanisms associated with the development of antimicrobial drug resistance, international differences in definitions of resistance, ongoing efforts to track shifts in drug susceptibility, and factors that can influence the selection of therapeutic intervention. The latter presents a matrix of complex variables that includes the mechanism of drug action, the pharmacokinetics (PK) of the antimicrobial agent in the targeted patient population, the pharmacodynamics (PD) of the bacterial response to the antimicrobial agent, the PK/PD relationship that will influence dose selection, and the integrity of the host immune system. Finally, the differences between bacterial tolerance and bacterial resistance are considered, and the potential for non-traditional anti-infective therapies is discussed.

  7. Design and Evaluation of Novel Antimicrobial and Anticancer Agents Among Tetrazolo[1,5-c]quinazoline-5-thione S-Derivatives

    PubMed Central

    Antypenko, Lyudmyla M.; Kovalenko, Sergey I.; Antypenko, Olexii M.; Katsev, Andrey M.; Achkasova, Olena M.

    2013-01-01

    be considered as a useful base for future development of potent antimicrobials and antitumor agents among tetrazolo[1,5-c]quinazoline-5-thione S-derivatives. PMID:23641327

  8. Augmentin (amoxicillin/clavulanate) in the treatment of community-acquired respiratory tract infection: a review of the continuing development of an innovative antimicrobial agent.

    PubMed

    White, Anthony R; Kaye, Clive; Poupard, James; Pypstra, Rienk; Woodnutt, Gary; Wynne, Brian

    2004-01-01

    Amoxicillin/clavulanate (Augmentin) is a broad-spectrum antibacterial that has been available for clinical use in a wide range of indications for over 20 years and is now used primarily in the treatment of community-acquired respiratory tract infections. Amoxicillin/clavulanate was developed to provide a potent broad spectrum of antibacterial activity, coverage of beta-lactamase-producing pathogens and a favourable pharmacokinetic/pharmacodynamic (PK/PD) profile. These factors have contributed to the high bacteriological and clinical efficacy of amoxicillin/clavulanate in respiratory tract infection over more than 20 years. This is against a background of increasing prevalence of antimicrobial resistance, notably the continued spread of beta-lactamase-mediated resistance in Haemophilus influenzae and Moraxella catarrhalis, and penicillin, macrolide and quinolone resistance in Streptococcus pneumoniae. The low propensity of amoxicillin/clavulanate to select resistance mutations as well as a favourable PK/PD profile predictive of high bacteriological efficacy may account for the longevity of this combination in clinical use. However, in certain defined geographical areas, the emergence of S. pneumoniae strains with elevated penicillin MICs has been observed. In order to meet the need to treat drug-resistant S. pneumoniae, two new high-dose amoxicillin/clavulanate formulations have been developed. A pharmacokinetically enhanced tablet dosage form of amoxicillin/clavulanate 2000/125 mg twice daily (available as Augmentin XR in the USA), has been developed for use in adult respiratory tract infection due to drug-resistant pathogens, such as S. pneumoniae with reduced susceptibility to penicillin, as well as beta-lactamase-producing H. influenzae and M. catarrhalis. Amoxicillin/clavulanate 90/6.4 mg/kg/day in two divided doses (Augmentin ES-600) is for paediatric use in persistent or recurrent acute otitis media where there are risk factors for the involvement of beta

  9. [Bacteria isolated from surgical infections and its susceptibilities to antimicrobial agents - Special references to bacteria isolated between April 2011 and March 2012].

    PubMed

    Shinagawa, Nagao; Taniguchi, Masaaki; Hirata, Koichi; Furuhata, Tomohisa; Mizuguchi, Tohru; Osanai, Hiroyuki; Yanai, Yoshiyuki; Hata, Fumitake; Kihara, Chikasi; Sasaki, Kazuaki; Oono, Keisuke; Nakamura, Masashi; Shibuya, Hitoshi; Hasegawa, Itaru; Kimura, Masami; Watabe, Kosho; Hoshikawa, Tsuyoshi; Oshima, Hideki; Aikawa, Naoki; Sasaki, Junichi; Suzuki, Masaru; Sekine, Kazuhiko; Abe, Shinya; Takeyama, Hiromitsu; Wakasugi, Takehiro; Mashita, Keiji; Tanaka, Moritsugu; Mizuno, Akira; Ishikawa, Masakazu; Iwai, Akihiko; Saito, Takaaki; Muramoto, Masayuki; Kubo, Shoji; Lee, Shigeru; Fukuhara, Kenichiro; Kobayashi, Yasuhito; Yamaue, Hiroki; Hirono, Seiko; Takesue, Yoshio; Fujiwara, Toshiyoshi; Shinoura, Susumu; Kimura, Hideyuki; Iwagaki, Hiromi; Tokunaga, Naoyuki; Sueda, Taijiro; Hiyama, Eiso; Murakami, Yoshiaki; Ohge, Hiroki; Uemura, Kenichiro; Tsumura, Hiroaki; Kanehiro, Tetsuya; Takeuchi, Hitoshi; Tanakaya, Kouji; Iwasaki, Mitsuhiro

    2014-12-01

    predominantly isolated, followed by Bacteroides caccae, B. thetaiotaomicron, Bacteroides ovatus and B. wadsworthia, in this order. In this series, vancomycin-resistant MRSA (methicillin-resistant Staphylococcus aureus), vancomycin-resistant Enterococcus spp. and multidrug-resistant P. aeruginosa were not observed. We should carefully follow up B. wadsworthia which was resistant to various antimicrobial agents, and also Bacteroides spp. which was resistant to many β-lactams.

  10. Usefulness of gram-stained sputum obtained just after administration of antimicrobial agents as the earliest therapeutic indicator for evaluating the effectiveness of empiric therapy in community-acquired pneumonia caused by pneumococcus or Moraxella catarrhalis.

    PubMed

    Fujisaki, Ryuichi; Yamaoka, Toshimori; Yamamura, Michiko; Kawakami, Sayoko; Ono, Yasuo; Miyazawa, Yukihisa; Teramoto, Tamio; Nishiya, Hajime

    2013-06-01

    We present here three cases in which morphological changes and/or a decreased number of Streptococcus pneumoniae or Moraxella catarrhalis could be observed in gram-stained sputum obtained just after the first administration of an antimicrobial agent. Case 1 was a 53-year-old man with pneumonia caused by gram-positive diplococcus, identified as S. pneumoniae, who was administered 2 g of ampicillin over a period of 1 h. Gram-stained sputum showed smaller or gram-negative pneumococci at the completion of administration of the agent, a decreased number of cocci at 1 h after administration, and almost no cocci at 12 h after the completion of administration. Case 2 was a 72-year-old woman with pneumonia caused by diplococcus, identified as S. pneumoniae, who was administered 2 g of ampicillin over a period of 1 h. Gram-stained sputum showed weakly stained, small cocci at the completion of administration of the agent and few cocci at 1 h after the completion of administration. Case 3 was a 58-year-old woman with pneumonia caused by a gram-negative diplococcus, identified as Moraxella catarrhalis, who was administered 1 g of cefotaxime over a period of 30 min. Gram-stained sputum showed few extracellular cocci and some intracellular cocci inside neutrophils 1 h after administration and no cocci 2 h after the completion of administration. These three cases showed that gram-stained sputum obtained just after and/or 1 h after administration of the first antimicrobial agent were suitable as the quickest therapeutic indicator of the effectiveness of empiric therapy, with the effectiveness of the agent being shown much earlier than with markers such as the white blood cell count and C-reactive protein level.

  11. Antimicrobial Pesticides

    MedlinePlus

    Jump to main content US EPA United States Environmental Protection Agency Search Search Pesticides Share Facebook Twitter Google+ ... of antimicrobial pesticides (Part 158W) Antimicrobials play an important role in public health and safety. While providing ...

  12. Resistance to Antimicrobial Peptides in Vibrios

    PubMed Central

    Destoumieux-Garzón, Delphine; Duperthuy, Marylise; Vanhove, Audrey Sophie; Schmitt, Paulina; Wai, Sun Nyunt

    2014-01-01

    Vibrios are associated with a broad diversity of hosts that produce antimicrobial peptides (AMPs) as part of their defense against microbial infections. In particular, vibrios colonize epithelia, which function as protective barriers and express AMPs as a first line of chemical defense against pathogens. Recent studies have shown they can also colonize phagocytes, key components of the animal immune system. Phagocytes infiltrate infected tissues and use AMPs to kill the phagocytosed microorganisms intracellularly, or deliver their antimicrobial content extracellularly to circumvent tissue infection. We review here the mechanisms by which vibrios have evolved the capacity to evade or resist the potent antimicrobial defenses of the immune cells or tissues they colonize. Among their strategies to resist killing by AMPs, primarily vibrios use membrane remodeling mechanisms. In particular, some highly resistant strains substitute hexaacylated Lipid A with a diglycine residue to reduce their negative surface charge, thereby lowering their electrostatic interactions with cationic AMPs. As a response to envelope stress, which can be induced by membrane-active agents including AMPs, vibrios also release outer membrane vesicles to create a protective membranous shield that traps extracellular AMPs and prevents interaction of the peptides with their own membranes. Finally, once AMPs have breached the bacterial membrane barriers, vibrios use RND efflux pumps, similar to those of other species, to transport AMPs out of their cytoplasmic space. PMID:27025756

  13. Antimicrobials Treatment

    NASA Astrophysics Data System (ADS)

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

    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.

  14. “Specificity Determinants” Improve Therapeutic Indices of Two Antimicrobial Peptides Piscidin 1 and Dermaseptin S4 against the Gram-negative Pathogens Acinetobacter baumannii and Pseudomonas aeruginosa

    PubMed Central

    Jiang, Ziqing; Vasil, Adriana I.; Vasil, Michael L.; Hodges, Robert S.

    2014-01-01

    A new class of antimicrobial agents with lower rates of resistance and different targets is urgently needed because of the rapidly increasing resistance to classical antibiotics. Amphipathic cationic α-helical antimicrobial peptides (AMPs) represent such a class of compounds. In our previous studies, using a 26-residue de novo designed antimicrobial peptide, we proposed the concept of “specificity determinant(s)”: positively charged residue(s) in the center of the non-polar face of AMPs that could decrease hemolytic activity/toxicity but increase or maintain the same level of antimicrobial activity to increase dramatically the therapeutic index. In the current study, we used d-enantiomers of two AMPs, Piscidin 1 isolated from fish and dermaseptin S4 isolated from frog. We substituted different positions in the center of the hydrophobic face with one or two lysine residue(s) (one or two “specificity determinant(s)”). This simple modification not only maintained or improved antimicrobial activity against Gram-negative pathogens Acinetobacter baumannii (11 strains) and Pseudomonas aeruginosa (6 strains), but also dramatically decreased hemolytic activity of human red blood cells, as predicted. Therapeutic indices improved by 55-fold and 730-fold for piscidin 1 (I9K) and dermaseptin S4 (L7K, A14K), respectively, against A. baumannii. Similarly, the therapeutic indices improved 32-fold and 980-fold for piscidin 1 (I9K) and dermaseptin S4 (L7K, A14K), respectively, against P. aeruginosa. PMID:24670666

  15. Antimicrobial activity of spherical silver nanoparticles prepared using a biocompatible macromolecular capping agent: evidence for induction of a greatly prolonged bacterial lag phase

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have evaluated the antimicrobial properties of Ag-based nanoparticles (Np) using two solid platform-based bioassays and found that 10-20 uL of 0.3-3 uM keratin-based Nps (depending on the starting bacteria concentration = CI) completely inhibited the growth of an equivalent volume of ca. 1,000 to...

  16. The Role of Topical Antiseptic Agents Within Antimicrobial Stewardship Strategies for Prevention and Treatment of Surgical Site and Chronic Open Wound Infection

    PubMed Central

    Roberts, Christopher D.; Leaper, David J.; Assadian, Ojan

    2017-01-01

    Scope and Significance: The topical use of antiseptics for wound care has a role in an antimicrobial stewardship strategy. However, the details of this role need clarification. Further clinical research into the use of topical antiseptics in wound care would lower the risk of furthering antibiotic resistance and contribute to more effective antibiotic use. As part of this research, experimental and surveillance data are needed on the resistance and tolerance patterns associated with topical antiseptic use in wound infections. Objective: The development of antibiotic resistance presents global challenges in terms of patient harm and increased healthcare costs. The treatment of “at risk” and infected wounds contributes to this conundrum. Synergies between antibiotics and antiseptics and their appropriate combined use need exploration. Approach: A review of available evidence on the appropriateness of antiseptics as a fundamental component of antimicrobial stewardship strategies has been undertaken. Innovation: Opening up new ways of thinking and identifying gaps of knowledge will lead to optimizing justification of antimicrobial choices and combinations. This may lead to changes in practice in terms of solutions for the prevention and treatment of wound infection. Conclusion: Antiseptics are an integral part of antimicrobial stewardship strategies for the prevention and treatment of surgical site and chronic open wound infections. PMID:28224049

  17. Antimicrobial activity and stability of protonectin with D-amino acid substitutions.

    PubMed

    Qiu, Shuai; Zhu, Ranran; Zhao, Yanyan; An, Xiaoping; Jia, Fengjing; Peng, Jinxiu; Ma, Zelin; Zhu, Yuanyuan; Wang, Jiayi; Su, Jinhuan; Wang, Qingjun; Wang, Hailin; Li, Yuan; Wang, Kairong; Yan, Wenjin; Wang, Rui

    2017-03-16

    The misuse and overuse of antibiotics result in the emergence of resistant bacteria and fungi, which make an urgent need of the new antimicrobial agents. Nowadays, antimicrobial peptides have attracted great attention of researchers. However, the low physiological stability in biological system limits the application of naturally occurring antimicrobial peptides as novel therapeutics. In the present study, we synthesized derivatives of protonectin by substituting all the amino acid residues or the cationic lysine residue with the corresponding D-amino acids. Both the D-enantiomer of protonectin (D-prt) and D-Lys-protonectin (D-Lys-prt) exhibited strong antimicrobial activity against bacteria and fungi. Moreover, D-prt showed strong stability against trypsin, chymotrypsin and the human serum, while D-Lys-prt only showed strong stability against trypsin. Circular dichroism analysis revealed that D-Lys-prt still kept typical α-helical structure in the membrane mimicking environment, while D-prt showed left hand α-helical structure. In addition, propidium iodide uptake assay and bacteria and fungi killing experiments indicated that all D-amino acid substitution or partially D-amino acid substitution analogs could disrupt the integrity of membrane and lead the cell death. In summary, these findings suggested that D-prt and D-Lys-prt might be promising candidate antibiotic agents for therapeutic application against resistant bacteria and fungi infection. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.

  18. Gas chromatographic method for the determination of residual monomers, 2-(acryloyloxy)ethyl isocyanate and 2-(methacryloyloxy)ethyl isocyanate, as curing agents in an ultraviolet curable adhesive.

    PubMed

    Kim, Byoung-Hyoun; Kim, Nosun; Moon, Dong Cheul

    2014-02-01

    A gas chromatographic method is described for the determination of residual 2-(acryloyloxy)ethyl isocyanate (AOI) and 2-(methacryloyloxy)ethyl isocyanate (MOI) as curing agents in an ultraviolet curable adhesive. Pre-column derivatization was employed in the determination of AOI and MOI as a means of enhancing the response of the flame ionization detector. Urethane derivatives of AOI and MOI were derived using methanol for 30 min at room temperature. The accuracies (n = 5, three concentration levels) were in the range of 113.4 to 126.7%, and precisions (n = 5, three concentration levels) were in the range of 0.8 to 4.3% for AOI-OMe. Furthermore, the accuracies were in the range of 79.5 to 108.6% and the precisions were in the range of 1.0 to 2.4% for MOI-OMe. The correlation coefficients of six calibration standards were all greater than 0.9999 for AOI-OMe and greater than 0.9998 for MOI-OMe over the range from 10 to 100 µg/mL.

  19. [Antimicrobial susceptibility cumulative reports].

    PubMed

    Canut-Blasco, Andrés; Calvo, Jorge; Rodríguez-Díaz, Juan Carlos; Martínez-Martínez, Luis

    2016-10-01

    Cumulative reports on antimicrobial susceptibility tests data are important for selecting empirical treatments, as an educational tool in programs on antimicrobial use, and for establishing breakpoints defining clinical categories. These reports should be based on data validated by clinical microbiologists using diagnostic samples (not surveillance samples). In order to avoid a bias derived from including several isolates obtained from the same patient, it is recommended that, for a defined period, only the first isolate is counted. A minimal number of isolates per species should be presented: a figure of >=30 isolates is statistically acceptable. The report is usually presented in a table format where, for each cell, information on clinically relevant microorganisms-antimicrobial agents is presented. Depending on particular needs, multiple tables showing data related to patients, samples, services or special pathogens can be prepared.

  20. Antimicrobial activity of spices.

    PubMed

    Arora, D S; Kaur, J

    1999-08-01

    Spices have been shown to possess medicinal value, in particular, antimicrobial activity. This study compares the sensitivity of some human pathogenic bacteria and yeasts to various spice extracts and commonly employed chemotherapeutic substances. Of the different spices tested only garlic and clove were found to possess antimicrobial activity. The bactericidal effect of garlic extract was apparent within 1 h of incubation and 93% killing of Staphylococcus epidermidis and Salmonella typhi was achieved within 3 h. Yeasts were totally killed in 1 h by garlic extract but in 5 h with clove. Some bacteria showing resistance to certain antibiotics were sensitive to extracts of both garlic and clove. Greater anti-candidal activity was shown by garlic than by nystatin. Spices might have a great potential to be used as antimicrobial agents.

  1. Characterisation and cooperative antimicrobial properties of chitosan/nano-ZnO composite nanofibrous membranes.

    PubMed

    Wang, Yan; Zhang, Qun; Zhang, Chen-Lu; Li, Ping

    2012-05-01

    Chitosan was combined with nano-ZnO to increase its antimicrobial activity, using polyvinyl alcohol as a support, and then were electronspun to form composite nanofibres. Through SEM, EDX and XRD observations, chitosan was seen to be able to incorporate nano-ZnO in the composite nanofibres. Escherichia coli, expressing recombinant enhanced green fluorescent protein, and Candida albicans were used to test the antimicrobial efficacy of the newly synthesised chitosan/nano-ZnO antimicrobial composite. The CdTe quantum dots were used to rapidly detect the residual changes of C. albicans and determine the end point of using antimicrobial agents. Minimal minimum inhibitory concentration (MIC), post-antibiotic effect and continuous agent effect of the composite were determined. The MIC of chitosan/nano-ZnO against C. albicans was 160μg/ml, close to the concentration of the treated composite with the lowest fluorescence intensity. The cell damage was observed by SEM, which indicated that nano-ZnO in the nanofibrous membranes played a cooperative role in the antimicrobial process of chitosan.

  2. The Potential of Antimicrobial Peptides as Biocides

    PubMed Central

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

    2011-01-01

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

  3. Isolation and Identification of the Antimicrobial Agent Beauvericin from the Endophytic Fusarium oxysporum 5-19 with NMR and ESI-MS/MS

    PubMed Central

    Ruan, Chuanfen; Bai, Xuelian; Zhang, Miao; Zhu, Shuangshuang; Jiang, Yingying

    2016-01-01

    Endophytic microbe has been proved to be one of rich sources of bioactive natural products with potential application for new drug and pesticide discovery. One cyclodepsipeptide, beauvericin, was firstly isolated from the fermentation broth of Fusarium oxysporum 5-19 endophytic on Edgeworthia chrysantha Linn. Its chemical structure was unambiguously identified by a combination of spectroscopic methods, such as HRESI-MS and 1H and 13C NMR. ESI-MS/MS was successfully used to elucidate the splitting decomposition route of the positive molecule ion of beauvericin. Antimicrobial results showed that this cyclodepsipeptide had inhibitory effect on three human pathogenic microbes, Candida albicans, Escherichia coli, and Staphylococcus aureus. In particular, beauvericin exhibited the strongest antimicrobial activity against S. aureus with MIC values of 3.91 μM, which had similar effect with that of the positive control amoxicillin. PMID:27413733

  4. Synthesis and biological screening of 2'-aryl/benzyl-2-aryl-4-methyl-4',5-bithiazolyls as possible anti-tubercular and antimicrobial agents.

    PubMed

    Abhale, Yogita K; Sasane, Amit V; Chavan, Abhijit P; Deshmukh, Keshav K; Kotapalli, Sudha Sravanti; Ummanni, Ramesh; Sayyad, Sadikali F; Mhaske, Pravin C

    2015-04-13

    A series of 2'-aryl/benzyl-2-aryl-4-methyl-4',5-bithiazolyl derivatives, 25-64 were synthesized and evaluated for inhibitory activity against Mycobacterium smegmatis MC(2) 155 strain and antimicrobial activities against four pathogenic bacteria Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Proteus vulgaris. Among them, compounds 40, 49, 50, and 54 exhibited moderate to good inhibition on the growth of the bacteria Mycobacterium smegmatis at the concentration of 30 μM. Compounds 26, 40, 44, 54 and 56 exhibited moderate to good antibacterial activity. Compound 5-(2'-(4-fluorobenzyl)thiazol-4'-yl)-2-(4-fluorophenyl)-4-methyl-thiazole (54) exhibited both antitubercular as well as antimicrobial activity against all tested strains.

  5. Design, synthesis and pharmacological screening of β-amino-, thiadiazole/thiadiazine-phosphonate based triazole motifs as antimicrobial/cytotoxic agents.

    PubMed

    Abdou, Wafaa M; Ganoub, Neven A; Sabry, Eman

    2014-09-01

    Three different series of phosphonate derivatives, β-amino- and fused thiadiazolo/thiadiazine-phosphonates have been synthesized using the addition and/or addition-cyclization protocol of Horner-Wadsworth-Emmons (HWE) reagents to 1,2,4-triazole-3-thiols. The design of potentially antimicrobial and anticancer phosphor esters relied on the results of computer-assisted molecular modeling. All synthesized phosphonates were evaluated for their in vitro antimicrobial activities while anticancer properties were determined for eight out of twenty new phosphonates. The tested phosphonates, except for compounds that have a nitrile moiety, exhibited moderate to significant antimicrobial activity. Nevertheless, the most active compounds were fused thiadiazole-phosphonates, which inhibited the growth of both Gram-negative and Gram-positive bacteria better than β-aminophosphonates and fused thiadiazolophosphonates. In parallel, the antitumor activity screenings of selected phosphonates from each series and substrate 1 were also done. Their antitumor properties against ten carcinoma cell lines, including breast (MCF7, MDA-MB- 231/ ATCC, MDA-MB-435, BT-549), ovarian (IGROVI, OVCAR-3, SK-OV-3), prostate (PX-3, PU-145), and liver (HEPG2), were investigated. The results showed that all synthesized compounds reflected remarkable antitumor activity against breast (especially MDA-MB-231/ATCC and BT-549), and prostate carcinoma cell lines (PC-3 and DU-145), whereas a moderate to good effect on ovarian and liver cancer cells was observed.

  6. An Environmentally Benign Antimicrobial Coating Based on a Protein Supramolecular Assembly.

    PubMed

    Gu, Jin; Su, Yajuan; Liu, Peng; Li, Peng; Yang, Peng

    2017-01-11

    The use of antimicrobial materials, for example, silver nanoparticles, has been a cause for concern because they often exert an adverse effect on environmental and safety during their preparation and use. In this study, we report a class of green antimicrobial coating based on a supramolecular assembly of a protein extracted from daily food, without the addition of any other hazardous agents. It is found that a self-assembled nanofilm by mere hen egg white lysozyme has durable in vitro and in vivo broad-spectrum antimicrobial efficacy against Gram-positive/negative and fungi. Such enhanced antimicrobial capability over native lysozyme is attributed to a synergistic combination of positive charge and hydrophobic amino acid residues enriched on polymeric aggregates in the lysozyme nanofilm. Accompanied with high antimicrobial activity, this protein-based PTL material simultaneously exhibits the integration of multiple functions including antifouling, antibiofilm, blood compatibility, and low cytotoxicity due to the existence of surface hydration effect. Moreover, the bioinspired adhesion mediated by the amyloid structure contained in the nanofilm induces robust transfer and self-adhesion of the material onto virtually arbitrary substrates by a simple one-step aqueous coating or solvent-free printing in 1 min, thereby allowing an ultrafast route into practical implications for surface-functionalized commodity and biomedical devices. Our results demonstrate that the application of pure proteinaceous substance may afford a cost-effective green biomaterial that has high antimicrobial activity and low environmental impact.

  7. Antimicrobial dyes and mechanosensitive channels.

    PubMed

    Boulos, Ramiz A

    2013-08-01

    The search for new and effective antimicrobial agents has never been as important; however, since the discovery of antibiotics, exploring the antimicrobial activity of dyes has been forgotten. Antimicrobial dyes are an untapped resource and have the ability to potentially combat the spread of drug-resistant bacteria either alone or as antimicrobial adjuvants. The mechanosensitive ion channel of large conductance (MscL) is highly conserved and ubiquitous in bacterial species. There is evidence to suggest that at least one triphenylmethane dye acts through the highly conserved MscL channel and combining the two approaches of exploring the mechanism of action of other triphenylmethane dyes or antimicrobial dyes in general and the novel MscL target provides a new opportunity for further exploration.

  8. Antimicrobial (Drug) Resistance Prevention

    MedlinePlus

    ... Visitor Information Contact Us Research > NIAID's Role in Research > Antimicrobial (Drug) Resistance > Understanding share with facebook share with twitter ... Prevention, Antimicrobial (Drug) Resistance Antimicrobial (Drug) Resistance Antimicrobial ... To prevent antimicrobial resistance, you and your healthcare ...

  9. Fate and transport of antimicrobials and antimicrobial resistance genes in soil and runoff following land application of swine slurry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to the use of antimicrobials in livestock production, residual antimicrobials and antimicrobial resistance genes (ARGs) could enter the environment following the land application of animal wastes and could further contaminate surface and groundwater. The objective of this study was to determine ...

  10. Using Chemical Probes to Assess the Feasibility of Targeting SecA for Developing Antimicrobial Agents against Gram-Negative Bacteria.

    PubMed

    Jin, Jinshan; Hsieh, Ying-Hsin; Cui, Jianmei; Damera, Krishna; Dai, Chaofeng; Chaudhary, Arpana S; Zhang, Hao; Yang, Hsiuchin; Cao, Nannan; Jiang, Chun; Vaara, Martti; Wang, Binghe; Tai, Phang C

    2016-11-21

    With the widespread emergence of drug resistance, there is an urgent need to search for new antimicrobials, especially those against Gram-negative bacteria. Along this line, the identification of viable targets is a critical first step. The protein translocase SecA is commonly believed to be an excellent target for the development of broad-spectrum antimicrobials. In recent years, we developed three structural classes of SecA inhibitors that have proven to be very effective against Gram-positive bacteria. However, we have not achieved the same level of success against Gram-negative bacteria, despite the potent inhibition of SecA in enzyme assays by the same inhibitors. In this study, we use representative inhibitors as chemical probes to gain an understanding as to why these inhibitors were not effective against Gram-negative bacteria. The results validate our initial postulation that the major difference in effectiveness against Gram-positive and Gram-negative bacteria is in the additional permeability barrier posed by the outer membrane of Gram-negative bacteria. We also found that the expression of efflux pumps, which are responsible for multidrug resistance (MDR), have no effect on the effectiveness of these SecA inhibitors. Identification of an inhibitor-resistant mutant and complementation tests of the plasmids containing secA in a secAts mutant showed that a single secA-azi-9 mutation increased the resistance, providing genetic evidence that SecA is indeed the target of these inhibitors in bacteria. Such results strongly suggest SecA as an excellent target for developing effective antimicrobials against Gram-negative bacteria with the intrinsic ability to overcome MDR. A key future research direction should be the optimization of membrane permeability.

  11. Complexes of Silver(I) Ions and Silver Phosphate Nanoparticles with Hyaluronic Acid and/or Chitosan as Promising Antimicrobial Agents for Vascular Grafts

    PubMed Central

    Chudobova, Dagmar; Nejdl, Lukas; Gumulec, Jaromir; Krystofova, Olga; Rodrigo, Miguel Angel Merlos; Kynicky, Jindrich; Ruttkay-Nedecky, Branislav; Kopel, Pavel; Babula, Petr; Adam, Vojtech; Kizek, Rene

    2013-01-01

    Polymers are currently widely used to replace a variety of natural materials with respect to their favourable physical and chemical properties, and due to their economic advantage. One of the most important branches of application of polymers is the production of different products for medical use. In this case, it is necessary to face a significant disadvantage of polymer products due to possible and very common colonization of the surface by various microorganisms that can pose a potential danger to the patient. One of the possible solutions is to prepare polymer with antibacterial/antimicrobial properties that is resistant to bacterial colonization. The aim of this study was to contribute to the development of antimicrobial polymeric material ideal for covering vascular implants with subsequent use in transplant surgery. Therefore, the complexes of polymeric substances (hyaluronic acid and chitosan) with silver nitrate or silver phosphate nanoparticles were created, and their effects on gram-positive bacterial culture of Staphylococcus aureus were monitored. Stages of formation of complexes of silver nitrate and silver phosphate nanoparticles with polymeric compounds were characterized using electrochemical and spectrophotometric methods. Furthermore, the antimicrobial activity of complexes was determined using the methods of determination of growth curves and zones of inhibition. The results of this study revealed that the complex of chitosan, with silver phosphate nanoparticles, was the most suitable in order to have an antibacterial effect on bacterial culture of Staphylococcus aureus. Formation of this complex was under way at low concentrations of chitosan. The results of electrochemical determination corresponded with the results of spectrophotometric methods and verified good interaction and formation of the complex. The complex has an outstanding antibacterial effect and this effect was of several orders higher compared to other investigated complexes

  12. Complexes of silver(I) ions and silver phosphate nanoparticles with hyaluronic acid and/or chitosan as promising antimicrobial agents for vascular grafts.

    PubMed

    Chudobova, Dagmar; Nejdl, Lukas; Gumulec, Jaromir; Krystofova, Olga; Rodrigo, Miguel Angel Merlos; Kynicky, Jindrich; Ruttkay-Nedecky, Branislav; Kopel, Pavel; Babula, Petr; Adam, Vojtech; Kizek, Rene

    2013-06-28

    Polymers are currently widely used to replace a variety of natural materials with respect to their favourable physical and chemical properties, and due to their economic advantage. One of the most important branches of application of polymers is the production of different products for medical use. In this case, it is necessary to face a significant disadvantage of polymer products due to possible and very common colonization of the surface by various microorganisms that can pose a potential danger to the patient. One of the possible solutions is to prepare polymer with antibacterial/antimicrobial properties that is resistant to bacterial colonization. The aim of this study was to contribute to the development of antimicrobial polymeric material ideal for covering vascular implants with subsequent use in transplant surgery. Therefore, the complexes of polymeric substances (hyaluronic acid and chitosan) with silver nitrate or silver phosphate nanoparticles were created, and their effects on gram-positive bacterial culture of Staphylococcus aureus were monitored. Stages of formation of complexes of silver nitrate and silver phosphate nanoparticles with polymeric compounds were characterized using electrochemical and spectrophotometric methods. Furthermore, the antimicrobial activity of complexes was determined using the methods of determination of growth curves and zones of inhibition. The results of this study revealed that the complex of chitosan, with silver phosphate nanoparticles, was the most suitable in order to have an antibacterial effect on bacterial culture of Staphylococcus aureus. Formation of this complex was under way at low concentrations of chitosan. The results of electrochemical determination corresponded with the results of spectrophotometric methods and verified good interaction and formation of the complex. The complex has an outstanding antibacterial effect and this effect was of several orders higher compared to other investigated complexes.

  13. Click chemistry approach: regioselective one-pot synthesis of some new 8-trifluoromethylquinoline based 1,2,3-triazoles as potent antimicrobial agents.

    PubMed

    Garudachari, B; Isloor, Arun M; Satyanarayana, M N; Fun, Hoong-Kun; Hegde, Gurumurthy

    2014-03-03

    Three series of 8-trifluoromethylquinoline based 1,2,3-triazoles derivatives (5a-c, 6a-d and 7a-c) were synthesized by multi-step reactions by click chemistry approach. Synthesized compounds were characterized by spectral studies and X-ray analysis. The final compounds were screened for their in-vitro antimicrobial activity by well plate method (zone of inhibition). Compounds 5c, 6b, 8b, 11 and 12 were found to be active against tested microbial strains. The results are summarized in Tables 5 and 6.

  14. In Vitro Activities of Ceftazidime-Avibactam, Aztreonam-Avibactam, and a Panel of Older and Contemporary Antimicrobial Agents against Carbapenemase-Producing Gram-Negative Bacilli

    PubMed Central

    Vasoo, Shawn; Cunningham, Scott A.; Cole, Nicolynn C.; Kohner, Peggy C.; Menon, Sanjay R.; Krause, Kevin M.; Harris, Kelly A.; De, Partha P.; Koh, Tse Hsien

    2015-01-01

    Among 177 carbapenemase-producing Gram-negative bacilli (108 KPC, 32 NDM, 11 IMP, 8 OXA-48, 4 OXA-181, 2 OXA-232, 5 IMI, 4 VIM, and 3 SME producers), aztreonam-avibactam was active against all isolates except two NDM producers with elevated MICs of 8/4 and 16/4 mg/liter; ceftazidime-avibactam was active against all KPC-, IMI-, SME-, and most OXA-48 group-producing isolates (93%) but not metallo-β-lactamase producers. Among older and contemporary antimicrobials, the most active were colistin, tigecycline, and fosfomycin, with overall susceptibilities of 88%, 79%, and 78%, respectively. PMID:26392487

  15. Bacillus cereus brain abscesses occurring in a severely neutropenic patient: successful treatment with antimicrobial agents, granulocyte colony-stimulating factor and surgical drainage.

    PubMed

    Sakai, C; Iuchi, T; Ishii, A; Kumagai, K; Takagi, T

    2001-07-01

    Multiple brain and liver abscesses developed immediately after Bacillus cereus bacteremia in a neutropenic patient with acute lymphoblastic leukemia. After even 8 weeks of antimicrobial chemotherapy together with administration of granulocyte colony-stimulating factor, every infectious process disappeared but the patient's headache has still persisted. Because the wall of one brain abscess became thin and was in danger of rupturing into the ventricle, surgical drainage was performed, resulting in disappearance of headache and resolution of brain abscess. The present case indicates that a combined medical and surgical approach is mandatory to treat patients with brain abscesses.

  16. [Antimicrobial mechanisms of action].

    PubMed

    Calvo, Jorge; Martínez-Martínez, Luis

    2009-01-01

    A large number of families and groups of antimicrobial agents are of clinical interest. The mechanisms by which compounds with antibacterial activity inhibit growth or cause bacterial death are varied and depend on the affected targets. The bacterial cell wall-a unique structure in most bacteria that is absent in eukaryotic cells-can be affected in several ways: at different stages of synthesis (fosfomycin, cycloserine) or transport (bacitracin, mureidomycins) of its metabolic precursors, or by a direct action on its structural organization (beta-lactams, glycopeptides). The main drugs affecting the cytoplasmic membrane are polymyxins and daptomycin. Protein synthesis can be blocked by a large variety of compounds that affect any of the phases of this process, including activation (mupirocin), initiation (oxazolidinones, aminoglycosides), binding of the tRNA amino acid complex to ribosomes (tetracyclines, glycylcyclines) and elongation (amphenicols, lincosamides, macrolides, ketolides, streptogramins, fusidic acid). The metabolism of nucleic acids can be altered at the DNA-dependent RNA polymerase or in the process of DNA coiling (quinolones); some compounds affect DNA directly (nitroimidazoles, nitrofurans). Trimethoprim and sulfamides (often used in combination) are examples of antimicrobial agents that block bacterial metabolic pathways. Some compounds are unable to inhibit or kill bacteria in themselves, but can block bacterial mechanisms of resistance, enhancing the activity of other antimicrobials administered in combination. Among this group of agents, only certain beta-lactamase inhibitors are currently in clinical use.

  17. Methods of Antimicrobial Coating of Diverse Materials

    NASA Technical Reports Server (NTRS)

    Akse, James R.; Holtsnider, John T.; Kliestik, Helen

    2011-01-01

    Methods of coating diverse substrate materials with antimicrobial agents have been developed. Originally intended to reduce health risks to astronauts posed by pathogenic microorganisms that can grow on surfaces in spacecraft, these methods could also be used on Earth for example, to ensure sterility of surgical inserts and other medical equipment. The methods involve, generally, chemical preparation of substrate surfaces to enable attachment of antimicrobial molecules to the substrate surfaces via covalent bonds. Substrate materials that have been treated successfully include aluminum, glass, a corrosion-resistant nickel alloy, stainless steel, titanium, and poly(tetrafluoroethylene). Antimicrobial agents that have been successfully immobilized include antibiotics, enzymes, bacteriocins, bactericides, and fungicides. A variety of linkage chem istries were employed. Activity of antimicrobial coatings against gram-positive bacteria, gram-negative bacteria, and fungi was demonstrated. Results of investigations indicate that the most suitable combination of antimicrobial agent, substrate, and coating method depends upon the intended application.

  18. Antimicrobial peptides: an alternative for innovative medicines?

    PubMed

    da Costa, João Pinto; Cova, Marta; Ferreira, Rita; Vitorino, Rui

    2015-03-01

    Antimicrobial peptides are small molecules with activity against bacteria, yeasts, fungi, viruses, bacteria, and even tumor cells that make these molecules attractive as therapeutic agents. Due to the alarming increase of antimicrobial resistance, interest in alternative antimicrobial agents has led to the exploitation of antimicrobial peptides, both synthetic and from natural sources. Thus, many peptide-based drugs are currently commercially available for the treatment of numerous ailments, such as hepatitis C, myeloma, skin infections, and diabetes. Initial barriers are being increasingly overcome with the development of cost-effective, more stable peptides. Herein, we review the available strategies for their synthesis, bioinformatics tools for the rational design of antimicrobial peptides with enhanced therapeutic indices, hurdles and shortcomings limiting the large-scale production of AMPs, as well as the challenges that the pharmaceutical industry faces on their use as therapeutic agents.

  19. Chemical Composition, Antimicrobial Activity, and Mode of Action of Essential Oils against Paenibacillus larvae, Etiological Agent of American Foulbrood on Apis mellifera.

    PubMed

    Pellegrini, María C; Alonso-Salces, Rosa M; Umpierrez, María L; Rossini, Carmen; Fuselli, Sandra R

    2016-12-10

    This study aimed to characterize the chemical composition of Aloysia polystachia, Acantholippia seriphioides, Schinus molle, Solidago chilensis, Lippia turbinata, Minthostachys mollis, Buddleja globosa, and Baccharis latifolia essential oils (EOs), and to evaluate their antibacterial activities and their capacity to provoke membrane disruption in Paenibacillus larvae, the bacteria that causes the American Foulbrood (AFB) disease on honey bee larvae. The relationship between the composition of the EOs and these activities on P. larvae was also analyzed. Monoterpenes were the most abundant compounds in all EOs. All EOs showed antimicrobial activity against P. larvae and disrupted the cell wall and cytoplasmic membrane of P. larvae provoking the leakage of cytoplasmic constituents (with the exception of B. latifolia EO). While, the EOs' antimicrobial activity was correlated most strongly to the content of pulegone, carvone, (Z)-β-ocimene, δ-cadinene, camphene, terpinen-4-ol, elemol, β-pinene, β-elemene, γ-cadinene, α-terpineol, and bornyl acetate; the volatiles that better explained the membrane disruption were carvone, limonene, cis-carvone oxide, pentadecane, trans-carvyl acetate, trans-carvone oxide, trans-limonene oxide, artemisia ketone, trans-carveol, thymol, and γ-terpinene (positively correlated) and biciclogermacrene, δ-2-carene, verbenol, α-pinene, and α-thujene (negatively correlated). The studied EOs are proposed as natural alternative means of control for the AFB disease.

  20. Triclosan antimicrobial polymers

    PubMed Central

    Petersen, Richard C.

    2016-01-01

    Triclosan antimicrobial molecular fluctuating energies of nonbonding electron pairs for the oxygen atom by ether bond rotations are reviewed with conformational computational chemistry analyses. Subsequent understanding of triclosan alternating ether bond rotations is able to help explain several material properties in Polymer Science. Unique bond rotation entanglements between triclosan and the polymer chains increase both the mechanical properties of polymer toughness and strength that are enhanced even better through secondary bonding relationships. Further, polymer blend compatibilization is considered due to similar molecular relationships and polarities. With compatibilization of triclosan in polymers a more uniform stability for nonpolar triclosan in the polymer solid state is retained by the antimicrobial for extremely low release with minimum solubility into aqueous solution. As a result, triclosan is projected for long extended lifetimes as an antimicrobial polymer additive. Further, triclosan rapid alternating ether bond rotations disrupt secondary bonding between chain monomers in the resin state to reduce viscosity and enhance polymer blending. Thus, triclosan is considered for a polymer additive with multiple properties to be an antimicrobial with additional benefits as a nonpolar toughening agent and a hydrophobic wetting agent. The triclosan material relationships with alternating ether bond rotations are described through a complete different form of medium by comparisons with known antimicrobial properties that upset bacterial cell membranes through rapid fluctuating mechanomolecular energies. Also, triclosan bond entanglements with secondary bonding can produce structural defects in weak bacterial lipid membranes requiring pliability that can then interfere with cell division. Regarding applications with polymers, triclosan can be incorporated by mixing into a resin system before cure, melt mixed with thermoplastic polymers that set on cooling

  1. Design of self-processing antimicrobial peptides for plant protection.

    PubMed

    Powell, W A; Catranis, C M; Maynard, C A

    2000-08-01

    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.

  2. National Antimicrobial Resistance Monitoring System (NARMS) Program

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The National Antimicrobial Resistance Monitoring System (NARMS) – Enteric Bacteria is a national public health surveillance system in the United States that tracks changes in the susceptibility of certain enteric bacteria to antimicrobial agents of human and veterinary medical importance. The NARMS ...

  3. A fabric phase sorptive extraction-High performance liquid chromatography-Photo diode array detection method for the determination of twelve azole antimicrobial drug residues in human plasma and urine.

    PubMed

    Locatelli, Marcello; Kabir, Abuzar; Innosa, Denise; Lopatriello, Teresa; Furton, Kenneth G

    2017-01-01

    This paper reports a novel fabric phase sorptive extraction-high performance liquid chromatography-photodiode array detection (FPSE-HPLC-PDA) method for the simultaneous extraction and analysis of twelve azole antimicrobial drug residues that include ketoconazole, terconazole, voriconazole, bifonazole, clotrimazole, tioconazole, econazole, butoconazole, miconazole, posaconazole, ravuconazole, and itraconazole in human plasma and urine samples. The selected azole antimicrobial drugs were well resolved by using a Luna C18 column (250mm×4.6mm; 5μm particle size) in gradient elution mode within 36min. The analytical method was calibrated and validated in the range from 0.1 to 8μg/mL for all the drug compounds. Blank human plasma and urine were used as the sample matrix for the analysis; while benzyl-4-hydroxybenzoate was used as the internal standard (IS). The limit of quantification of the FPSE-HPLC-PDA method was found as 0.1μg/mL and the weighted-matrix matched standard calibration curves of the drugs showed a good linearity upto a concentration of 8μg/mL. The parallelism tests were also performed to evaluate whether overrange sample can be analyzed after dilution, without compromising the analytical performances of the validated method. The intra- and inter-day precision (RSD%) values were found ≤13.1% and ≤13.9%, respectively. The intra- and inter-day trueness (bias%) values were found in the range from -12.1% to 10.5%. The performances of the validated FPSE-HPLC-PDA were further tested on real samples collected from healthy volunteers after a single dose administration of itraconazole and miconazole. To the best of our knowledge, this is the first FPSE extraction procedure applied on plasma and urine samples for the simultaneous determination of twelve azole drugs possessing a wide range of logKow values (extending from 0.4 for fluconazole to 6.70 of butoconazole) and could be adopted as a rapid and robust green analytical tool for clinical and

  4. One pot three components microwave assisted and conventional synthesis of new 3-(4-chloro-2-hydroxyphenyl)-2-(substituted) thiazolidin-4-one as antimicrobial agents.

    PubMed

    Pansare, Dattatraya N; Mulla, Nayeem A; Pawar, Chandrakant D; Shende, Vikas R; Shinde, Devanand B

    2014-08-01

    A one-pot, three-component, microwave assisted and conventional synthesis of new 3-(4-chloro-2-hydroxyphenyl)-2-(substituted) thiazolidin-4-one (4a-n) was carried out by using N,N-dimethylformamide as a solvent with high product yield. Among these synthesized compounds (4f, 4g, 4l and 4m) were found to be a broad spectrum molecule active against all bacterial and fungus strains tested, except fungus Aspergillus niger. Amongst the compounds (4g, 4l and 4m) were found to be more potent than respective standard drugs used in the experiment against Candida albicans, Staphylococcus aureus and Aspergillus flavus, respectively. All synthesized compounds were also tested for their cytotoxic activity against HeLa and MCF-7 cell lines by the sulforhodamine B (SRB) assay. This study shows that all compounds were non-cytotoxic in nature, and confirmed their antimicrobial specificity apart from any general cytotoxicity.

  5. Residue determination of two co-administered antibacterial agents--cephalexin and colistin--in calf tissues using high-performance liquid chromatography and microbiological methods.

    PubMed

    Leroy, P; Decolin, D; Nicolas, S; Archimbault, P; Nicolas, A

    1989-01-01

    Residues of two antibacterial agents, cephalexin and colistin, co-administered by intramuscular injection to calves, were quantified in four different tissues (muscle, fat, liver and kidney) by column switching HPLC and by a microbiological method. For cephalexin assay, tissue samples with cephradin as internal standard were homogenized in a 5% trichloroacetic acid solution and filtrates were injected onto a concentration precolumn filled with LiChroprep RP-18 (25-40 microns). A clean-up step was incorporated by flowing a mobile phase (methanol-0.01 M phosphate buffer (pH 3.0); 15:85, v/v) through the enrichment column before elution on a LiChrospher RP-18e (5 microns) column with a methanol-phosphate buffer (30:70, v/v) at a flow rate of 1 ml min-1. Spectrometric detection was at 260 nm. An additional "off-line" washing step of extracts with methylene chloride was operated to achieve higher selectivity in the case of liver and kidney samples. The limit for quantitative assay was 0.045 micrograms g-1 with relative standard deviations in the range 5-8% and recoveries within 70%. For microbiological assay of colistin, samples were homogenized in 0.1 M hydrochloric acid-acetonitrile mixtures (3:1, v/v, for kidney and liver; 3:2, v/v, for fat and muscle). The supernatants were assayed by the cylinder plate method after evaporation to dryness under vacuum. Bordetella bronchiseptica ATCC 4617 was chosen as test organism. After a 3-h diffusion step at room temperature, the medium was incubated at 37 degrees C for 18 h and then the diameter of the growth inhibition zones was measured. Sensitivity reached 0.10-0.15 micrograms g-1. Results from the analysed samples over a 7-28 day period after drug administration show that no cephalexin was found at concentrations higher than the quantitation limit in the four test tissues and that colistin was found in muscle (injection site only) for 15 days and in kidney for 21 days.

  6. The First Salamander Defensin Antimicrobial Peptide

    PubMed Central

    Jiang, Ke; Rong, Mingqiang; Lai, Ren

    2013-01-01

    Antimicrobial peptides have been widely identified from amphibian skins except salamanders. A novel antimicrobial peptide (CFBD) was isolated and characterized from skin secretions of the salamander, Cynops fudingensis. The cDNA encoding CFBD precursor was cloned from the skin cDNA library of C. fudingensis. The precursor was composed of three domains: signal peptide of 17 residues, mature peptide of 41 residues and intervening propeptide of 3 residues. There are six cysteines in the sequence of mature CFBD peptide, which possibly form three disulfide-bridges. CFBD showed antimicrobial activities against Staphylococcus aureus, Bacillus subtilis, Candida albicans and Escherichia coli. This peptide could be classified into family of β-defensin based on its seqeuence similarity with β-defensins from other vertebrates. Evolution analysis indicated that CFBD was close to fish β-defensin. As far as we know, CFBD is the first β-defensin antimicrobial peptide from salamanders. PMID:24386139

  7. The first salamander defensin antimicrobial peptide.

    PubMed

    Meng, Ping; Yang, Shilong; Shen, Chuanbin; Jiang, Ke; Rong, Mingqiang; Lai, Ren

    2013-01-01

    Antimicrobial peptides have been widely identified from amphibian skins except salamanders. A novel antimicrobial peptide (CFBD) was isolated and characterized from skin secretions of the salamander, Cynops fudingensis. The cDNA encoding CFBD precursor was cloned from the skin cDNA library of C. fudingensis. The precursor was composed of three domains: signal peptide of 17 residues, mature peptide of 41 residues and intervening propeptide of 3 residues. There are six cysteines in the sequence of mature CFBD peptide, which possibly form three disulfide-bridges. CFBD showed antimicrobial activities against Staphylococcus aureus, Bacillus subtilis, Candida albicans and Escherichia coli. This peptide could be classified into family of β-defensin based on its sequence similarity with β-defensins from other vertebrates. Evolution analysis indicated that CFBD was close to fish β-defensin. As far as we know, CFBD is the first β-defensin antimicrobial peptide from salamanders.

  8. Antimicrobial Resistance Mechanisms among Campylobacter

    PubMed Central

    2013-01-01

    Campylobacter jejuni and Campylobacter coli are recognized as the most common causative agents of bacterial gastroenteritis in the world. Humans most often become infected by ingesting contaminated food, especially undercooked chicken, but also other sources of bacteria have been described. Campylobacteriosis is normally a self-limiting disease. Antimicrobial treatment is needed only in patients with more severe disease and in those who are immunologically compromised. The most common antimicrobial agents used in the treatment of Campylobacter infections are macrolides, such as erythromycin, and fluoroquinolones, such as ciprofloxacin. Tetracyclines have been suggested as an alternative choice in the treatment of clinical campylobacteriosis but in practice are not often used. However, during the past few decades an increasing number of resistant Campylobacter isolates have developed resistance to fluoroquinolones and other antimicrobials such as macrolides, aminoglycosides, and beta-lactams. Trends in antimicrobial resistance have shown a clear correlation between use of antibiotics in the veterinary medicine and animal production and resistant isolates of Campylobacter in humans. In this review, the patterns of emerging resistance to the antimicrobial agents useful in treatment of the disease are presented and the mechanisms of resistance to these drugs in Campylobacter are discussed. PMID:23865047

  9. Antimicrobial resistance mechanisms among Campylobacter.

    PubMed

    Wieczorek, Kinga; Osek, Jacek

    2013-01-01

    Campylobacter jejuni and Campylobacter coli are recognized as the most common causative agents of bacterial gastroenteritis in the world. Humans most often become infected by ingesting contaminated food, especially undercooked chicken, but also other sources of bacteria have been described. Campylobacteriosis is normally a self-limiting disease. Antimicrobial treatment is needed only in patients with more severe disease and in those who are immunologically compromised. The most common antimicrobial agents used in the treatment of Campylobacter infections are macrolides, such as erythromycin, and fluoroquinolones, such as ciprofloxac