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Sample records for aureus challenged antimicrobial

  1. Antimicrobial drug resistance ofStaphylococcus aureus in dairy products

    Institute of Scientific and Technical Information of China (English)

    Sasidharan S; Prema B; Yoga Latha L

    2011-01-01

    Objective:To evaluate the prevalence of multidrug resistantStaphylococcus aureus(S. aureus) in dairy products.Methods:Isolation and identification ofS. aureus were performed in3 dairy-based food products. The isolates were tested for their susceptibility to5 different common antimicrobial drugs.Results:Of50 samples examined,5 (10%) were contaminated with S. aureus. Subsequently, the5 isolates were subjected to antimicrobial resistance pattern using five antibiotic discs (methicillin, vancomycin, kanamycin, chloramphenicol and tetracycline). Sample 29 showed resistance to methicillin and vancomycin. Sample18 showed intermediate response to tetracycline. The other samples were susceptible to all the antibiotics tested.Conclusions:The results provide preliminary data on sources of food contamination which may act as vehicles for the transmission of antimicrobial-resistantStaphylococcus.Therefore, it enables us to develop preventive strategies to avoid the emergence of new strains of resistantS. aureus.

  2. ANTIMICROBIAL RESISTANCE PATTERN OF STAPHYLOCOCCUS AUREUS ISOLATES FROM DAKSHINA KANNADA

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    Rao Venkatakrishna

    2011-03-01

    Full Text Available Methicillin resistant Staphylococcus aureus (MRSA is an important cause of infections in hospitals and pose a great challenge to the treating clinicians; even emergence of vancomycin resistance has been reported. Therefore the knowledge of prevalence of MRSA and their antimicrobial profile becomes necessary. This study is aimed to determine prevalence of MRSA and their antimicrobial sensitivity pattern in Dakshina Kannada.Clinical specimens and carrier samples were cultured as per standard methods. The isolates were identified by using catalase test, coagulase tube test, mannitol fermentation and DNAase test. Antimicrobial susceptibility test was done for the isolates as per Kirby-Bauer disc diffusion method; the isolates were also tested for methicillin resistance using oxacillin and cefoxitin discs.A total of 250 isolates were tested (200 clinical isolates and 50 from carriers and 67 MRSA isolates were obtained (52 clinical samples and 15 from carriers. The degree of resistance to penicillin, ampicillin, ciprofloxacin, clindamycin and erythromycin were 100%, 100%, 53-56%, 14-16 % and 45-48% respectively. Resistance to vancomycin was not found. As the degree of resistance of MRSA towards antibiotics varies from region to region, in vitro susceptibility testing of every isolate of MRSA in clinical laboratories is inevitable.

  3. Repurposing the antihistamine terfenadine for antimicrobial activity against Staphylococcus aureus.

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    Perlmutter, Jessamyn I; Forbes, Lauren T; Krysan, Damian J; Ebsworth-Mojica, Katherine; Colquhoun, Jennifer M; Wang, Jenna L; Dunman, Paul M; Flaherty, Daniel P

    2014-10-23

    Staphylococcus aureus is a rapidly growing health threat in the U.S., with resistance to several commonly prescribed treatments. A high-throughput screen identified the antihistamine terfenadine to possess, previously unreported, antimicrobial activity against S. aureus and other Gram-positive bacteria. In an effort to repurpose this drug, structure-activity relationship studies yielded 84 terfenadine-based analogues with several modifications providing increased activity versus S. aureus and other bacterial pathogens, including Mycobacterium tuberculosis. Mechanism of action studies revealed these compounds to exert their antibacterial effects, at least in part, through inhibition of the bacterial type II topoisomerases. This scaffold suffers from hERG liabilities which were not remedied through this round of optimization; however, given the overall improvement in activity of the set, terfenadine-based analogues provide a novel structural class of antimicrobial compounds with potential for further characterization as part of the continuing process to meet the current need for new antibiotics.

  4. Staphylococcus aureus resistance to topical antimicrobials in atopic dermatitis*

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    Bessa, Giancarlo Rezende; Quinto, Vanessa Petry; Machado, Daiane Corrêa; Lipnharski, Caroline; Weber, Magda Blessmann; Bonamigo, Renan Rangel; D'Azevedo, Pedro Alves

    2016-01-01

    Background Topical antimicrobial drugs are indicated for limited superficial pyodermitis treatment, although they are largely used as self-prescribed medication for a variety of inflammatory dermatoses, including atopic dermatitis. Monitoring bacterial susceptibility to these drugs is difficult, given the paucity of laboratory standardization. Objective To evaluate the prevalence of Staphylococcus aureus topical antimicrobial drug resistance in atopic dermatitis patients. Methods We conducted a cross-sectional study of children and adults diagnosed with atopic dermatitis and S. aureus colonization. We used miscellaneous literature reported breakpoints to define S. aureus resistance to mupirocin, fusidic acid, gentamicin, neomycin and bacitracin. Results A total of 91 patients were included and 100 S. aureus isolates were analyzed. All strains were methicillin-susceptible S. aureus. We found a low prevalence of mupirocin and fusidic acid resistance (1.1% and 5.9%, respectively), but high levels of neomycin and bacitracin resistance (42.6% and 100%, respectively). Fusidic acid resistance was associated with more severe atopic dermatitis, demonstrated by higher EASI scores (median 17.8 vs 5.7, p=.009). Our results also corroborate the literature on the absence of cross-resistance between the aminoglycosides neomycin and gentamicin. Conclusions Our data, in a southern Brazilian sample of AD patients, revealed a low prevalence of mupirocin and fusidic acid resistance of S. aureus atopic eczema colonizer strains. However, for neomycin and bacitracin, which are commonly used topical antimicrobial drugs in Brazil, high levels of resistance were identified. Further restrictions on the use of these antimicrobials seem necessary to keep resistance as low as possible. PMID:27828633

  5. Antimicrobial susceptibility pattern of Staphylococcus aureus isolated from clinical specimens in Northern area of Jordan

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    Mazhar Salim Al Zoubi

    2015-12-01

    Full Text Available Background and Objectives: The global spread of methicillin resistant Staphylococcus aureus (MRSA constitutes one of the most serious contemporary challenges to the treatment of hospital-acquired infections. We aimed to screen and assess the antibiotic susceptibility pattern of Staphylococcus aureus isolated from clinical specimens in local hospitals of Northern province in Jordan.Materials and Methods: Staphylococcus aureus was isolated and identified using standard methods from various clinical specimens of different infected body sites from 358 patients during the period from January 2005 to November 2008.Results: Our analysis showed that 31.6% of S. aureus infections were MRSA, while 31% were multidrug resistance (MDR and 42.7% were Oxacillin-resistant (ORSA. Most of these strains were isolated from wound specimens. All isolates were susceptible to vancomycin (100%. They were also susceptible to chloramphenicol, linezolid, nitrofurantoin, rifampicin and teicoplanin (>80%, but showed resistance to erythromycin and penicillin.Conclusion: Vancomycin was the most effective antimicrobial agent against S. aureus. We recommend regular surveillance of hospital associated infections and monitoring antibiotic sensitivity pattern and strict drug policy for antibiotics used within and outside the hospital environments. Keywords: Staphylococcus aureus, MRSA, MDR

  6. Genome-Wide Identification of Antimicrobial Intrinsic Resistance Determinants in Staphylococcus aureus

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    Vestergaard, Martin; Leng, Bingfeng; Haaber, Jakob;

    2016-01-01

    that confer intrinsic resistance to antimicrobial agents may be explored for alternative antimicrobial therapies, by potentiating the efficacy of existing antimicrobials. In this study, we identified the intrinsic resistome to a broad spectrum of antimicrobials in the human pathogen, Staphylococcus aureus. We...

  7. The challenges of antimicrobial resistance in Brazil.

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    Rossi, Flávia

    2011-05-01

    Brazil is a country with continental proportions with high geographic and economic diversity. Despite its medical centers of excellence, antimicrobial resistance poses a major therapeutic challenge. Rates of methicillin-resistant Staphylococcus aureus are up to 60% and are related to an endemic Brazilian clone. Local resistance to vancomycin in Enterococci was first related to Enterococcus faecalis, which differs from European and American epidemiology. Also, local Klebsiella pneumoniae and Escherichia coli isolates producing extended-spectrum β-lactamases have a much higher prevalence (40%-50% and 10%-18%, respectively). Carbapenem resistance among the enterobacteriaceae group is becoming a major problem, and K. pneumoniae carbapenemase isolates have been reported in different states. Among nonfermenters, carbapenem resistance is strongly related to SPM-1 (Pseudomonasaeruginosa) and OXA-23 (Acinetobacter baumannii complex) enzymes, and a colistin-only susceptible phenotype has also emerged in these isolates, which is worrisome. Local actions without loosing the global resistance perspective will demand multidisciplinary actions, new policies, and political engagement.

  8. Resistencia antimicrobiana de cepas de Staphylococcus aureus, Costa Rica Antimicrobial resistance of Staphylococcus aureus, Costa Rica

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    Víctor Hugo Alvarado

    2011-12-01

    Full Text Available Objetivo: Determinar y comparar los perfiles de resistencia de cepas de S. aureus aisladas de quesos, producidos en la Zona Sur de Costa Rica y de un centro hospitalario de la misma región. Materiales y Métodos: Se analizaron 35 muestras de queso fresco, adquiridas durante los meses de setiembre y octubre del 2010 en la zona de San Vito de Coto Brus. A cada muestra se le realizaron recuentos de coliformes totales, coliformes fecales y Staphylococcus aureus. Adicionalmente se analizó presencia/ausencia de Listeria monocytogenes en 25 gramos del producto. A las cepas identificadas como S. aureus se les realizó la prueba de sensibilidad a los antibióticos mediante el sistema automatizado Vitek y la interpretación de los datos se realizó siguiendo las pautas del Clinical and Laboratory Standards Institute antimicrobial susceptibility testing 2011. Adicional a esto se recolectaron datos acerca de la sensibilidad de las cepas de S. aureus aisladas e identificadas en el Hospital de San Vito de Coto Brus en el mismo período. Resultados: El promedio obtenido para el recuento de coliformes totales fue de 9,7 X 10(6 UFC/g, para coliformes fecales de 6,7 X 10(5 y para S. aureus de 2,8 X 10(5 UFC/g, obteniéndose un 83 % de muestras positivas por esta bacteria. En cuanto a la resistencia antimicrobiana, se obtuvieron porcentajes de resistencia mayores en las cepas de origen clínico. Se encontró también que 23 de las cepas (96% provenientes de muestras clínicas, presentaban resistencia a más de un antibiótico, mientras que siete de las obtenidas a partir de queso (27% presentaban esta característica. Con respecto a los betalactamicos (ampicilina, oxacilina y penicilina se observó la existencia de una diferencia estadísticamente significativa (pObjective: determined and compared the resistance patters of S. aureus strains isolated from cheese produced in the southern zone of Costa Rica and from clinical samples isolated at the hospital center

  9. ANTISTAPHYBASE: database of antimicrobial peptides (AMPs) and essential oils (EOs) against methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus aureus.

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    Zouhir, Abdelmajid; Taieb, Malek; Lamine, Mohamed Ashraf; Cherif, Ammar; Jridi, Taoufik; Mahjoubi, Basma; Mbarek, Sarra; Fliss, Ismail; Nefzi, Adel; Sebei, Khaled; Ben Hamida, Jeannette

    2017-03-01

    Staphylococcus aureus and methicillin-resistant S. aureus are major pathogens. The antimicrobial peptides and essential oils (EOs) display narrow- or broad-spectrum activity against bacteria including these strains. A centralized resource, such as a database, designed specifically for anti-S. aureus/anti-methicillin-resistant S. aureus antimicrobial peptides and EOs is therefore needed to facilitate the comprehensive investigation of their structure/activity associations and combinations. The database ANTISTAPHYBASE is created to facilitate access to important information on antimicrobial peptides and essential peptides against methicillin-resistant S. aureus and S. aureus. At the moment, the database contains 596 sequences of antimicrobial peptides produced by diverse organisms and 287 essential oil records. It permits a quick and easy search of peptides based on their activity as well as their general, physicochemical properties and literature data. These data are very useful to perform further bioinformatic or chemometric analysis and would certainly be useful for the development of new drugs for medical use. The ANTISTAPHYBASE database is freely available at: https://www.antistaphybase.com/ .

  10. Antimicrobial blue light inactivation of Methicillin-resistant Staphylococcus aureus

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    Wang, Yucheng; Dai, Tianhong; Gu, Ying

    2016-10-01

    Background: With the increasing emergence of multidrug-resistant (MDR) bacterial strains, there is a pressing need for the development of alternative treatment for infections. Antimicrobial blue light (aBL) has provided a simple and effective approach. Methods: We first investigated the effectiveness of aBL (415 nm) inactivation of USA300 LAClux (a communityacquired Methicillin-resistant Staphylococcus aureus strain) both in the planktonic and biofilm forms. The survival of the bacteria in suspensions was determined by serial dilution and that of the biofilm-embedded bacteria was determined by bioluminescence quantification. Using a mouse model of thermal burn infected with USA300 LAClux, we further assessed the effectiveness of aBL for treating localized infections. Bioluminescence imaging was performed to monitor in real time bacterial viability in vivo. Results: In vitro study showed that, for the planktonic counterpart of the bacteria or the 24-h-old biofilms, an irradiance of 55 mW/cm2 for 60 min resulted in a 4.61 log10 or 2.56 log10 inactivation, respectively. In vivo study using infected mouse burns demonstrated that a 2.56-log10 inactivation was achieved after 100-mW/cm2 irradiation for 62 min. Conclusions: aBL is a potential alternative approach for treating Methicillin-resistant Staphylococcus aureus infections.

  11. Human health risks associated with antimicrobial-resistant enterococci and Staphylococcus aureus on poultry meat

    DEFF Research Database (Denmark)

    Bortolaia, V.; Gongora, Carmen Espinosa; Guardabassi, L.

    2016-01-01

    and national reports on prevalence, bacterial load, antimicrobial resistance and clonal distribution of these three species on poultry meat. The risks associated with ingestion of antimicrobial-resistant enterococci of poultry origin comprise horizontal transfer of resistance genes and transmission...... interest to the human gut microbiota. Ingestion of poultry meat contaminated with S. aureus may lead to food poisoning. However, antimicrobial resistance in the toxin -producing strains does not have clinical implications because food poisoning is not managed by antimicrobial therapy. Recently methicillin...

  12. spa typing and antimicrobial resistance of Staphylococcus aureus from healthy humans, pigs and dogs in Tanzania

    DEFF Research Database (Denmark)

    Katakweba, Abdul S.; Muhairwa, Amandus P.; Espinosa-Gongora, Carmen

    2016-01-01

    Introduction: Staphylococcus aureus is an opportunistic pathogen causing infections in humans and animals. Here we report for the first time the prevalence of nasal carriage, spa typing and antimicrobial resistance of S. aureus in a Tanzanian livestock community. Methodology: Nasal swabs were tak...

  13. Triple-acting antimicrobial treatment for drug-resistant and intracellular Staphylococcus aureus.

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    Multi-drug resistant bacteria are a persistent problem in modern health care, food safety and animal health. There is a need for new antimicrobials to replace over-used conventional antibiotics. Staphylococcus aureus (S. aureus) is a notorious pathogen for both animal and human health with multi-d...

  14. Antimicrobial potential of Pakistani medicinal plants against multi-drug resistance Staphylococcus aureus

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    Rahat Ejaz

    2014-09-01

    Full Text Available Objective: To determine resistance patterns of Staphylococcus aureus (S. aureus isolated from different areas of Pakistan and to identify antimicrobial agents against multi-drug resistant S. aureus strains. Methods: A total of 67 samples (sewerage, nasal and milk were collected from different farm areas of Pakistan to identify local strains of S. aureus. Sixteen out of 67 samples were positive for S. aureus. Only 6 out of 16 S. aureus strains showed resistance to antibiotics. Then the antibacterial effect of 29 medicinal plants was evaluated on these S. aureus isolates and a standard S. aureus strain ATCC 25923. The solvents used for the extraction of plants were acetone, dimethyl sulfoxide and methanol. The in vitro antibacterial activity was performed using agar disc diffusion method. Moreover, minimum inhibitory concentration of effective medicinal plant extracts was identified through micro-dilution method to find out their 50% inhibitory concentration. Results: Plant extracts of 5 medicinal plants (Psidium guajava, Nigella sativa, Piper nigrum, Valeriana jatamansi, and Cucurbita pepo exhibited antibacterial activity against locally isolated multidrug resistant strains of S. aureus. The minimum inhibitory concentration of these extracts was ranged from 0.328 to 5.000 mg/mL. Conclusions: Plant extracts of Psidium guajava, Piper nigrum seed, Valeriana jatamansi, Cucurbita pepo and Nigella sativa showed significant in vitro antibacterial activity and thus, such findings may serve as valuable contribution in the treatment of infection and may contribute to the development of potential antimicrobial agents against multi drug resistant strains of S. aureus

  15. Antimicrobial potential of Pakistani medicinal plants against multi-drug resistance Staphylococcus aureus

    Institute of Scientific and Technical Information of China (English)

    Rahat Ejaz; Usman A Ashfaq; Sobia Idrees

    2014-01-01

    Objective: To determine resistance patterns of Staphylococcus aureus (S. aureus) isolated from different areas of Pakistan and to identify antimicrobial agents against multi-drug resistant S.aureus strains. Methods: A total of 67 samples (sewerage, nasal and milk) were collected from different farm areas of Pakistan to identify local strains of S. aureus. Sixteen out of 67 samples were positive for S.aureus. Only 6 out of 16 S. aureus strains showed resistance to antibiotics. Then the antibacterial effect of 29 medicinal plants was evaluated on these S. aureus isolates and a standard S. aureus strain ATCC 25923. The solvents used for the extraction of plants were acetone, dimethyl sulfoxide and methanol. The in vitro antibacterial activity was performed using agar disc diffusion method. Moreover, minimum inhibitory concentration of effective medicinal plant extracts was identified through micro-dilution method to find out their 50% inhibitory concentration.Results:Plant extracts of 5 medicinal plants (Psidium guajava, Nigella sativa, Piper nigrum, Valeriana jatamansi, and Cucurbita pepo) exhibited antibacterial activity against locally isolated multidrug resistant strains of S. aureus. The minimum inhibitory concentration of these extracts was ranged from 0.328 to 5.000 mg/mL. Conclusions: Plant extracts of Psidium guajava, Piper nigrum seed, Valeriana jatamansi, Cucurbita pepo and Nigella sativa showed significant in vitro antibacterial activity and thus, such findings may serve as valuable contribution in the treatment of infection and may contribute to the development of potential antimicrobial agents against multi drug resistant strains of S. aureus.

  16. Population structure and antimicrobial profile of Staphylococcus aureus strains associated with bovine mastitis in China.

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    Zhang, Lili; Li, Yuchen; Bao, Hongduo; Wei, Ruicheng; Zhou, Yan; Zhang, Hui; Wang, Ran

    2016-08-01

    Staphylococcus aureus is a significant bacterial pathogen associated with bovine mastitis. The aim of the present study was to investigate and characterize of S. aureus strains isolated from the milk of cows suffering from mastitis in the mid-east of China. Among the 200 milk samples analyzed, 58 were positive for S. aureus, of these isolates, 11 isolates were methicillin-resistant Staphylococcus aureus (MRSA). All of the 58 S. aureus strains were classified in agr group I, while seven different sequence type (ST) patterns were identified and among them the most common was ST630 followed by ST188. All of the S. aureus isolates belonging to ST630 were resistant to more than four antimicrobials, and 22.2% of isolates belonging to ST188 were resistant to eight antimicrobials. Interestingly, while strong biofilm producers demonstrated higher resistance to multiple antimicrobials, they exhibited lower intracellular survival rates. The results of this study illustrated the distribution, antimicrobial susceptibility profiles, genotype, and the ability of biofilm production and mammary epithelial cells invasion of these S. aureus isolates. This study can provide the basis for the development of a disease prevention program in dairy farms to reduce the potential risk in both animal and human health.

  17. Antimicrobial activity of selected phytochemicals against Escherichia coli and Staphylococcus aureus and their biofilms

    OpenAIRE

    2014-01-01

    Bacteria can be resistant to multiple antibiotics and we are fast approaching a time when antibiotics will not work on some bacterial infections. New antimicrobial compounds are urgently necessary. Plants are considered the greatest source to obtain new antimicrobials. This study aimed to assess the antimicrobial activity of four phytochemicals—7-hydroxycoumarin (7-HC), indole-3-carbinol (I3C), salicylic acid (SA) and saponin (SP)—against Escherichia coli and Staphylococcus aureus, either as...

  18. Genome-wide identification of antimicrobial intrinsic resistance determinants in Staphylococcus aureus

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    Martin Vestergaard

    2016-12-01

    Full Text Available The emergence of antimicrobial resistance severely threatens our ability to treat bacterial infections. While acquired resistance has received considerable attention, relatively little is known of intrinsic resistance that allows bacteria to naturally withstand antimicrobials. Gene products that confer intrinsic resistance to antimicrobial agents may be explored for alternative antimicrobial therapies, by potentiating the efficacy of existing antimicrobials. In this study, we identified the intrinsic resistome to a broad spectrum of antimicrobials in the human pathogen, Staphylococcus aureus. We screened the Nebraska Transposon Mutant Library of 1920 single-gene inactivations in S. aureus strain JE2, for increased susceptibility to the anti-staphylococcal antimicrobials (ciprofloxacin, oxacillin, linezolid, fosfomycin, daptomycin, mupirocin, vancomycin and gentamicin. 68 mutants were confirmed by E-test to display at least two-fold increased susceptibility to one or more antimicrobial agents. The majority of the identified genes have not previously been associated with antimicrobial susceptibility in S. aureus. For example, inactivation of genes encoding for subunits of the ATP synthase, atpA, atpB, atpG and atpH, reduced the minimum inhibitory concentration (MIC of gentamicin 16-fold. To elucidate the potential of the screen, we examined treatment efficacy in the Galleria mellonella infection model. Gentamicin efficacy was significantly improved, when treating larvae infected with the atpA mutant compared to wild type cells with gentamicin at a clinically relevant concentration. Our results demonstrate that many gene products contribute to the intrinsic antimicrobial resistance of S. aureus. Knowledge of these intrinsic resistance determinants provides alternative targets for compounds that may potentiate the efficacy of existing antimicrobial agents against this important pathogen.

  19. Antimicrobial activity of some sulfonamide derivatives on clinical isolates of Staphylococus aureus

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    Bekdemir Yunus

    2008-08-01

    Full Text Available Abstract Background Staphylococcus aureus is a non-motile, gram positive, non-sporforming, facultative anaerobic microorganism. It is one of the important bacteria as a potential pathogen specifically for nosocomial infections. The sulfonamide derivative medicines are preferred to cure infection caused by S. aureus due to methicillin resistance. Methods Antimicrobial activity of four sulfonamide derivatives have been investigated against 50 clinical isolates of S. aureus and tested by using MIC and disc diffusion methods. 50 clinical isolate which collected from specimens of patients who are given medical treatment in Ondokuz Mayis University Medical School Hospital. A control strain of S. aureus ATCC 29213 was also tested. Results The strongest inhibition was observed in the cases of I [N-(2-hydroxy-4-nitro-phenyl-4-methyl-benzensulfonamid], and II [N-(2-hydroxy-5-nitro-phenyl-4-methyl-benzensulfonamid] against S. aureus. Compound I [N-(2-hydroxy-4-nitro-phenyl-4-methyl-benzensulfonamid] showed higher effect on 21 S. aureus MRSAisolates than oxacillin antibiotic. Introducing an electron withdrawing on the ring increased the antimicrobial activity remarkably. Conclusion This study may help to suggest an alternative possible leading compound for development of new antimicrobial agents against MRSA and MSSA resistant S. aureus. It was also shown here that that clinical isolates of 50 S. aureus have various resistance patterns against to four sulfonamide derivatives. It may also be emphasized here that in vitro antimicrobial susceptibility testing results for S. aureus need standardization with further studies and it should also have a correlation with in vivo therapeutic response experiments.

  20. Risk factors associated with the antimicrobial resistance of Staphylococcus aureus isolated from bovine mastitis

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    Daniele C. Beuron

    2014-10-01

    Full Text Available The objective of this study was to evaluate herd management practices and mastitis treatment procedures as risk factors associated with Staphylococcus aureus antimicrobial resistance. For this study, 13 herds were selected to participate in the study to evaluate the association between their management practices and mastitis treatment procedures and in vitro antimicrobial susceptibility. A total of 1069 composite milk samples were collected aseptically from the selected cows in four different periods over two years. The samples were used for microbiological culturing of S. aureus isolates and evaluation of their antimicrobial susceptibility. A total of 756 samples (70.7% were culture-positive, and S. aureus comprised 27.77% (n=210 of the isolates. The S. aureus isolates were tested using the disk-diffusion susceptibility assay with the following antimicrobials: ampicillin 10mg; clindamycin 2μg; penicillin 1mg; ceftiofur 30μg; gentamicin 10mg; sulfa-trimethoprim 25μg; enrofloxacin 5μg; sulfonamide 300μg; tetracycline 30μg; oxacillin 1mg; cephalothin 30μg and erythromycin 5μg. The variables that were significantly associated with S. aureus resistance were as follows: the treatment of clinical mastitis for ampicillin (OR=2.18, dry cow treatment for enrofloxacin (OR=2.11 and not sending milk samples for microbiological culture and susceptibility tests, for ampicillin (OR=2.57 and penicillin (OR=4.69. In conclusion, the identification of risk factors for S. aureus resistance against various mastitis antimicrobials is an important information that may help in practical recommendations for prudent use of antimicrobial in milk production.

  1. Inhibition of Staphylococcus aureus by antimicrobial biofilms formed by competitive exclusion microorganisms on stainless steel.

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    Son, Hyeri; Park, Sunhyung; Beuchat, Larry R; Kim, Hoikyung; Ryu, Jee-Hoon

    2016-12-05

    The goal of this study was to develop a desiccation resistant antimicrobial surface using biofilm of competitive exclusion (CE) microorganism inhibitory to Staphylococcus aureus. We isolated 161 microorganisms from soils, foods, and food-contact surfaces that are inhibitory to S. aureus. Among them, three CE microorganisms (Streptomyces spororaveus strain Gaeunsan-18, Bacillus safensis strain Chamnamu-sup 5-25, and Pseudomonas azotoformans strain Lettuce-9) exhibiting strong antibacterial activity and high growth rates were selected for evaluation. These isolates formed biofilms within 24h on stainless steel coupons (SSCs) immersed in Bennet's broth and tryptic soy broth at 25°C. Cells in these biofilms showed significantly (P≤0.05) enhanced resistance to a desiccation (43% relative humidity [RH]) compared to those attached to SSCs but not in biofilms. The antimicrobial activities of biofilms formed by these isolates on SSCs against S. aureus at 25°C and 43% RH were determined. Compared to SSCs lacking biofilms formed by CE microorganisms, populations of S. aureus on SSCs harboring CE biofilms were significantly lower (P≤0.05). Results indicate that persistent antimicrobial activity against S. aureus on stainless steel surfaces can be achieved by the presence of biofilms of CE microorganisms. This information will be useful when developing strategies to improve the microbiological safety of foods during storage, processing, and distribution by facilitating the development of effective antimicrobial food-contact surfaces.

  2. Identification of pyruvate kinase in methicillin-resistant Staphylococcus aureus as a novel antimicrobial drug target.

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    Zoraghi, Roya; See, Raymond H; Axerio-Cilies, Peter; Kumar, Nag S; Gong, Huansheng; Moreau, Anne; Hsing, Michael; Kaur, Sukhbir; Swayze, Richard D; Worrall, Liam; Amandoron, Emily; Lian, Tian; Jackson, Linda; Jiang, Jihong; Thorson, Lisa; Labriere, Christophe; Foster, Leonard; Brunham, Robert C; McMaster, William R; Finlay, B Brett; Strynadka, Natalie C; Cherkasov, Artem; Young, Robert N; Reiner, Neil E

    2011-05-01

    Novel classes of antimicrobials are needed to address the challenge of multidrug-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA). Using the architecture of the MRSA interactome, we identified pyruvate kinase (PK) as a potential novel drug target based upon it being a highly connected, essential hub in the MRSA interactome. Structural modeling, including X-ray crystallography, revealed discrete features of PK in MRSA, which appeared suitable for the selective targeting of the bacterial enzyme. In silico library screening combined with functional enzymatic assays identified an acyl hydrazone-based compound (IS-130) as a potent MRSA PK inhibitor (50% inhibitory concentration [IC50] of 0.1 μM) with >1,000-fold selectivity over human PK isoforms. Medicinal chemistry around the IS-130 scaffold identified analogs that more potently and selectively inhibited MRSA PK enzymatic activity and S. aureus growth in vitro (MIC of 1 to 5 μg/ml). These novel anti-PK compounds were found to possess antistaphylococcal activity, including both MRSA and multidrug-resistant S. aureus (MDRSA) strains. These compounds also exhibited exceptional antibacterial activities against other Gram-positive genera, including enterococci and streptococci. PK lead compounds were found to be noncompetitive inhibitors and were bactericidal. In addition, mutants with significant increases in MICs were not isolated after 25 bacterial passages in culture, indicating that resistance may be slow to emerge. These findings validate the principles of network science as a powerful approach to identify novel antibacterial drug targets. They also provide a proof of principle, based upon PK in MRSA, for a research platform aimed at discovering and optimizing selective inhibitors of novel bacterial targets where human orthologs exist, as leads for anti-infective drug development.

  3. In vitro antimicrobial susceptibility of Staphylococcus aureus strains from dairy herds in KwaZulu-Natal

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    T. Schmidt

    2011-04-01

    Full Text Available Staphylococcus aureus is 1 of the most important causes of bovine mastitis and is responsible for significant economic losses to the dairy industry worldwide. One of the principal approaches used in treating intramammary infections is the administration of antimicrobials. Due to the propensity of S. aureus to develop resistance, antimicrobial susceptibility monitoring is necessary to ensure that treatment regimens are effective. As part of this investigation, 90 S. aureus strains isolated from mastitis cases submitted to Allerton Provincial Veterinary Laboratory during 2008 and 2009 were evaluated for their susceptibility to a panel of 10 antimicrobials. Only 8 of the 90 S. aureus isolates tested (8.9 % were found to be susceptible to all of the antimicrobials evaluated. A very high level of resistance to the beta-lactam antibiotics was noted: 47.8 % of the isolates were resistant to penicillin and 65.6 % were resistant to ampicillin. Minimal resistance to oxacillin, cephalothin and trimethoprim-sulfamethoxazole (1.1 % was found. Seventeen (18.9 % of the isolates tested were found to be resistant to 3 or more antimicrobials. The need for vigilant monitoring of bacterial resistance trends in the dairy industry is warranted as the potential public health implications are significant.

  4. Isolates of Staphylococcus aureus and saprophyticus resistant to antimicrobials isolated from the Lebanese aquatic environment.

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    Harakeh, Steve; Yassine, Hadi; Hajjar, Shady; El-Fadel, Mutasem

    2006-08-01

    The indiscriminate use of antimicrobials especially in developing countries has evoked serious bacterial resistance and led to the emergence of new and highly resistant strains of bacteria to commonly used antimicrobials. In Lebanon, pollution levels and bacterial infections are increasing at a high rate as a result of inadequate control measures to limit untreated effluent discharges into the sea or freshwater resources. The aim of this study was to isolate and molecularly characterize various Staphylococcus strains isolated from sea water, fresh water, sediments, and crab samples collected from representative communities along the coast of Lebanon. The results on the antimicrobial resistance indicated that the level of resistance of Staphylococcus aureus varied with various antimicrobials tested. The resistance patterns ranged between 45% in freshwater isolates and 54.8% in seawater ones. Fifty one percent of the tested isolates have shown resistance to at least one of the five tested antimicrobials; with seawater isolates exhibiting the highest rates of antimicrobial resistance.

  5. Antimicrobial properties of a lipid interactive -helical peptide VP1 against Staphylococcus aureus bacteria

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    Dennison, Sarah R.; Morton, Leslie H.G.; Harris, Frederick; Phoenix, David A.

    2007-01-01

    Antimicrobial properties of a lipid interactive -helical peptide VP1 against Staphylococcus aureus bacteria correspondance: Corresponding author. Tel: +44 1772 893481; fax: +44 1772 894981. (Phoenix, David A.) (Phoenix, David A.) Faculty of Science and Technology--> , University of Central Lancashire--> , Preston PR1 2HE--> - UNITED KINGDOM (Dennison, Sarah R) Department of Forensic and Inve...

  6. Quantitative structure-activity relationships of antimicrobial fatty acids and derivatives against Staphylococcus aureus

    Institute of Scientific and Technical Information of China (English)

    Hui ZHANG; Lu ZHANG; Li-juan PENG; Xiao-wu DONG; Di WU; Vivian Chi-Hua WU; Feng-qin FENG

    2012-01-01

    Fatty acids and derivatives (FADs) are resources for natural antimicrobials.In order to screen for additional potent antimicrobial agents,the antimicrobial activities of FADs against Staphylococcus aureus were examined using a microplate assay.Monoglycerides of fatty acids were the most potent class of fatty acids,among which monotridecanoin possessed the most potent antimicrobial activity.The conventional quantitative structure-activity relationship (QSAR) and comparative molecular field analysis (CoMFA) were performed to establish two statistically reliable models (conventional QSAR:R2=0.942,Q2LOO=0.910; CoMFA:R2=0.979,Q2=0.588,respectively).Improved forecasting can be achieved by the combination of these two models that provide a good insight into the structureactivity relationships of the FADs and that may be useful to design new FADs as antimicrobial agents.

  7. Antimicrobial properties of graphene-like nanoparticles: coating effect on Staphylococcus aureus

    Science.gov (United States)

    Olivi, M.; Alfè, M.; Gargiulo, V.; Valle, F.; Mura, F.; Di Giosia, M.; Rapino, S.; Palleschi, C.; Uccelletti, D.; Fiorito, S.

    2016-12-01

    The exploitation of nanomaterials with antimicrobial properties has attracted an ever-growing interest in the recent years. Carbon-based materials, such as graphene and graphene family materials (GFMs), have gained most of the attention for application in many biomedical fields. Here, we describe the antimicrobial activity of graphene-like (GL) layers derived from the chemical demolition of carbon black, against the planktonic growth of Staphylococcus aureus cells, primary cause of hospital and community-acquired infections, often leading to bacteremia and sepsis. The inhibitory capabilities of GL layers on the formation of S. aureus biofilm are also assessed. The antimicrobial properties seem based mainly on the interaction between GL layers and bacteria surfaces. FESEM and AFM analyses suggest that the GL layers coat the cells as soon as they get in contact with them, as also indicated by the wettability of the GLs.

  8. Occurence and antimicrobial resistance of Staphylococcus aureus and Salmonella spp. in retail fish samples in Turkey.

    Science.gov (United States)

    Ertas Onmaz, Nurhan; Abay, Secil; Karadal, Fulden; Hizlisoy, Harun; Telli, Nihat; Al, Serhat

    2015-01-15

    The aims of this study were to investigate the presence of Staphylococcus aureus and staphylococcal enterotoxins, as well as Salmonella spp. and to determine the antimicrobial susceptibilities of the isolates from fish samples. A total of 100 fish samples were analysed consisting of 30 anchovy, 35 trout and 35 sea bream. The presence of SEs was detected using ELISA and its genes confirmed by mPCR. Also, S. aureus and Salmonella spp. were detected in 9 (9%) and 5 (5%) samples, respectively. None of the S. aureus isolates had SEs and SEs genes. The resistance rates of the S. aureus isolates to erythromycin, tetracycline, and penicillin G were found to be 33% while Salmonella spp. isolates were resistant to trimethoprim-sulfamethoxazole, gentamicin and neomycine in 20%, 20% and 80%, respectively of the samples. It is of utmost important for public health that retail fish markets need to use hygienic practices in handling and processing operations.

  9. Prevalence, toxin gene profiles, and antimicrobial resistance of Staphylococcus aureus isolated from quick-frozen dumplings.

    Science.gov (United States)

    Hao, Dan; Xing, Xiaonan; Li, Guanghui; Wang, Xin; Zhang, Min; Zhang, Weisong; Xia, Xiaodong; Meng, Jianghong

    2015-01-01

    The aim of this study was to investigate the prevalence of Staphylococcus aureus in quick-frozen dumplings and to characterize these strains. A total of 120 dumpling samples, including lamb (n = 13), vegetarian (n = 14), seafood (n = 12), and pork (n = 81) stuffing, were collected in Shaanxi province in China and screened for S. aureus. All S. aureus isolates were characterized by antimicrobial susceptibility testing, and detection of genes encoding staphylococcal enterotoxins, exfoliative toxins A and B (eta and etb), toxic shock syndrome toxin 1 (tsst-1), and resistance to methicillin-oxacillin (mecA). In all, 60.0% of all samples were positive for S. aureus, and 117 S. aureus isolates, including seven mecA-positive strains, were recovered from these positive samples. In addition, all mecA-positive S. aureus isolates were recovered from products of animal origin. In these S. aureus isolates, resistance was observed most frequently to ampicillin (92.3%) and penicillin (86.3%), followed by clarithromycin, erythromycin, midecamycin, tetracycline, and kanahemycin (from 53.8 to 28.2%). All isolates were sensitive to cefoperazone, minocycline, vancomycin, and ofloxacin. The predominant toxin gene was sec (38.5%), followed by seg (19.7%), sej (16.2%), see (12.8%), sea (11.1%), and seb (10.3%), whereas eta, etb, and tsst-1 genes were not detected. These findings indicate that S. aureus was present commonly in quick-frozen dumplings, accompanied by multiple antimicrobial resistance and toxin genes. Our findings highlight the urgency for stricter hygiene strategies in food production and the prudent use of antibiotics in the breeding industry.

  10. Antimicrobial resistance and molecular epidemiology of Staphylococcus aureus from Ulaanbaatar, Mongolia

    Directory of Open Access Journals (Sweden)

    Rajeshwari Nair

    2013-10-01

    Full Text Available This study aimed to characterize Staphylococcus aureus (S. aureus strains isolated from human infections in Mongolia. Infection samples were collected at two time periods (2007–08 and 2011 by the National Center for Communicable Diseases (NCCD in Ulaanbaatar, Mongolia. S. aureus isolates were characterized using polymerase chain reaction (PCR for mecA, PVL, and sasX genes and tested for agr functionality. All isolates were also spa typed. A subset of isolates selected by frequency of spa types was subjected to antimicrobial susceptibility testing and multilocus sequence typing. Among 251 S. aureus isolates, genotyping demonstrated methicillin resistance in 8.8% of isolates (22/251. Approximately 28% of the tested S. aureus isolates were observed to be multidrug resistant (MDR. Sequence type (ST 154 (spa t667 was observed to be a strain with high virulence potential, as all isolates for this spa type were positive for PVL, had a functional agr system and 78% were MDR. S. aureus isolates of ST239 (spa t037 were observed to cause infections and roughly 60% had functional agr system with a greater proportion being MDR. Additionally, new multilocus sequence types and new spa types were identified, warranting continued surveillance for S. aureus in this region.

  11. Human health risks associated with antimicrobial-resistant enterococci and Staphylococcus aureus on poultry meat.

    Science.gov (United States)

    Bortolaia, V; Espinosa-Gongora, C; Guardabassi, L

    2016-02-01

    Enterococci and staphylococci are frequent contaminants on poultry meat. Enterococcus faecalis, Enterococcus faecium and Staphylococcus aureus are also well-known aetiological agents of a wide variety of infections resulting in major healthcare costs. This review provides an overview of the human health risks associated with the occurrence of these opportunistic human pathogens on poultry meat with particular focus on the risk of food-borne transmission of antimicrobial resistance. In the absence of conclusive evidence of transmission, this risk was inferred using data from scientific articles and national reports on prevalence, bacterial load, antimicrobial resistance and clonal distribution of these three species on poultry meat. The risks associated with ingestion of antimicrobial-resistant enterococci of poultry origin comprise horizontal transfer of resistance genes and transmission of multidrug-resistant E. faecalis lineages such as sequence type ST16. Enterococcus faecium lineages occurring in poultry meat products are distantly related to those causing hospital-acquired infections but may act as donors of quinupristin/dalfopristin resistance and other resistance determinants of clinical interest to the human gut microbiota. Ingestion of poultry meat contaminated with S. aureus may lead to food poisoning. However, antimicrobial resistance in the toxin-producing strains does not have clinical implications because food poisoning is not managed by antimicrobial therapy. Recently methicillin-resistant S. aureus of livestock origin has been reported on poultry meat. In theory handling or ingestion of contaminated meat is a potential risk factor for colonization by methicillin-resistant S. aureus. However, this risk is presently regarded as negligible by public health authorities.

  12. EARSS: European Antimicrobial Resistance Surveillance System; data from the Netherlands .Incidence and resistance rates for Streptococcus pneumoniae and Staphylococcus aureus

    NARCIS (Netherlands)

    Goettsch WG; Neeling AJ de; CIE; LIO

    2001-01-01

    In a porspective prevalence and incidence survey in The Netherlands in 1999 antimicrobial susceptibility data on invasive Streptococcus pneumoniae and Staphylococcus aureus infections were collected sithin the framework of European Antomicrobial Resistance Surveillance System (EARSS). The EARSS proj

  13. Australian Group on Antimicrobial Resistance Australian Staphylococcus aureus Sepsis Outcome Programme annual report, 2014.

    Science.gov (United States)

    Coombs, Geoffrey W; Daley, Denise A; Thin Lee, Yung; Pearson, Julie C; Robinson, J Owen; Nimmo, Graeme R; Collignon, Peter; Howden, Benjamin P; Bell, Jan M; Turnidge, John D

    2016-06-30

    From 1 January to 31 December 2014, 27 institutions around Australia participated in the Australian Staphylococcal Sepsis Outcome Programme (ASSOP). The aim of ASSOP 2014 was to determine the proportion of Staphylococcus aureus bacteraemia (SAB) isolates in Australia that are antimicrobial resistant, with particular emphasis on susceptibility to methicillin and to characterise the molecular epidemiology of the isolates. Overall, 18.8% of the 2,206 SAB episodes were methicillin resistant, which was significantly higher than that reported in most European countries. The 30-day all-cause mortality associated with methicillin-resistant SAB was 23.4%, which was significantly higher than the 14.4% mortality associated with methicillin-sensitive SAB (P important that antimicrobial resistance patterns in community and healthcare-associated SAB is monitored as this information will guide therapeutic practices in treating S. aureus sepsis.

  14. Colloidal silver fabrication using the spark discharge system and its antimicrobial effect on Staphylococcus aureus.

    Science.gov (United States)

    Tien, Der-Chi; Tseng, Kuo-Hsiung; Liao, Chih-Yu; Tsung, Tsing-Tshih

    2008-10-01

    Nanoscale techniques for silver production may assist the resurgence of the medical use of silver, especially given that pathogens are showing increasing resistance to antibiotics. Traditional chemical synthesis methods for colloidal silver (CS) may lead to the presence of toxic chemical species or chemical residues, which may inhibit the effectiveness of CS as an antibacterial agent. To counter these problems a spark discharge system (SDS) was used to fabricate a suspension of colloidal silver in deionized water with no added chemical surfactants. SDS-CS contains both metallic silver nanoparticles (Ag(0)) and ionic silver forms (Ag(+)). The antimicrobial affect of SDS-CS on Staphylococcus aureus was studied. The results show that CS solutions with an ionic silver concentration of 30 ppm or higher are strong enough to destroy S. aureus. In addition, it was found that a solution's antimicrobial potency is directly related to its level of silver ion concentration.

  15. Antimicrobial Activity of Essential Oils Against Staphylococcus aureus in Fresh Sheep Cheese

    Science.gov (United States)

    Sagrafoli, Daniele; Giacinti, Giuseppina; Rosa, Giulia; Carfora, Virginia; Marri, Nicla; Tammaro, Andreana; Bovi, Emanuela; Rosati, Remo

    2014-01-01

    Essential oils (EOs) are aromatic oily liquids extracted from different parts of specific plants, well known especially for their aromatic and antibacterial properties. Nowadays, EOs are exploited in the food sector mainly for their aromatic properties. Thanks to their antimicrobial activity, however, they could also be used as additives to increase the safety and the shelf-life of food products. Aim of this study was to assess the antimicrobial activity of Thymus vulgaris L. oil and of Origanum vulgare L. oil against Staphylococcus aureus both in vitro and on fresh cheese, and to determine whether the use of EOs can modify the microbiological and/or chemical-physical properties of the products. The antimicrobial activity against S. aureus in vitro was assessed by preparation of the aromatogram (diffusion in agar test), minimum inhibitory concentration test and minimum bactericidal concentration assessment. Raw sheep milk was experimentally contaminated with a strain of S. aureus ATCC 25922 and was used to produce three types of fresh cheese: without EOs, with thyme and oregano EOs (both EOs at a concentration of 1:1000). The samples were analysed on the day of production, after three and seven days. The results obtained from the tests showed that the concentration of S. aureus and the counts of lactic flora remained unchanged for all types of cheese. Even the chemical-physical parameters were constant. The results of inhibition tests on the cheese disagree with those relating to the in vitro tests. Most likely this is due to the ability of EOs to disperse in the lipids the food: the higher the fat content is, the lower the oil fraction will be able to exert the antimicrobial activity.

  16. Association between phage types and antimicrobial resistance among bovine Staphylococcus aureus from 10 countries

    DEFF Research Database (Denmark)

    Vintov, J.; Aarestrup, Frank Møller; Zinn, C. E.;

    2003-01-01

    This study was conducted to investigate the diversity of phage types and associations between penicillin resistance and phage types among 815 Staphylococcus aureus isolates from bovine mastitis in nine European countries and USA. All isolates were examined for susceptibility to antimicrobial agents...... associated with penicillin resistance in contrast to phage group I (P = 0.0023) and phage complex-80 (P = 0.0066). This study confirms that a large number of phage types of S. aureus cause bovine mastitis, but that some types predominate. In addition, these findings could indicate that the use of penicillin...... in the bovine environment has selected for specific types of S. aureus in countries with a high frequency of resistance....

  17. Antimicrobial susceptibility of Staphylococcus aureus and Staphylococcus pseudintermedius isolated from various animals.

    Science.gov (United States)

    Rubin, Joseph E; Ball, Katherine R; Chirino-Trejo, Manuel

    2011-02-01

    This study characterized the antimicrobial susceptibility of 221 Staphylococcus aureus isolated from various species, and 60 canine Staphylococcus pseudintermedius isolated from 1986 through 2000 at the Western College of Veterinary Medicine (WCVM). Resistance of S. aureus was most common to penicillin (31%) and tetracycline (14%); resistance of S. pseudintermedius to penicillin was present in 8% and to tetracycline in 34% of isolates. Resistance to trimethoprim/sulfamethoxazole was only seen among S. pseudintermedius, and there was no resistance to amoxicillin/clavulanate, ampicillin/sulbactam, cephalothin, amikacin, gentamicin, enrofloxacin, chloramphenicol, or rifampin among any isolate. Inducible clindamycin resistance was found in both S. aureus and S. pseudintermedius, highlighting the need for careful interpretation of culture and susceptibility test results. There were significant differences in the minimum inhibitory concentrations of penicillin, ciprofloxacin, enrofloxacin, clindamycin, erythromycin, chloramphenicol, and tetracycline between avian, bovine, equine, and porcine isolates.

  18. Bacterial Cytological Profiling (BCP as a Rapid and Accurate Antimicrobial Susceptibility Testing Method for Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    D.T. Quach

    2016-02-01

    Full Text Available Successful treatment of bacterial infections requires the timely administration of appropriate antimicrobial therapy. The failure to initiate the correct therapy in a timely fashion results in poor clinical outcomes, longer hospital stays, and higher medical costs. Current approaches to antibiotic susceptibility testing of cultured pathogens have key limitations ranging from long run times to dependence on prior knowledge of genetic mechanisms of resistance. We have developed a rapid antimicrobial susceptibility assay for Staphylococcus aureus based on bacterial cytological profiling (BCP, which uses quantitative fluorescence microscopy to measure antibiotic induced changes in cellular architecture. BCP discriminated between methicillin-susceptible (MSSA and -resistant (MRSA clinical isolates of S. aureus (n = 71 within 1–2 h with 100% accuracy. Similarly, BCP correctly distinguished daptomycin susceptible (DS from daptomycin non-susceptible (DNS S. aureus strains (n = 20 within 30 min. Among MRSA isolates, BCP further identified two classes of strains that differ in their susceptibility to specific combinations of beta-lactam antibiotics. BCP provides a rapid and flexible alternative to gene-based susceptibility testing methods for S. aureus, and should be readily adaptable to different antibiotics and bacterial species as new mechanisms of resistance or multidrug-resistant pathogens evolve and appear in mainstream clinical practice.

  19. Synergistic antimicrobial activity between pentacyclic triterpenoids and antibiotics against Staphylococcus aureus strains

    Directory of Open Access Journals (Sweden)

    Navaratnam Parasakthi

    2011-06-01

    Full Text Available Abstract Background There has been considerable effort to discover plant-derived antibacterials against methicillin-resistant strains of Staphylococcus aureus (MRSA which have developed resistance to most existing antibiotics, including the last line of defence, vancomycin. Pentacyclic triterpenoid, a biologically diverse plant-derived natural product, has been reported to show anti-staphylococcal activities. The objective of this study is to evaluate the interaction between three pentacyclic triterpenoid and standard antibiotics (methicillin and vancomycin against reference strains of Staphylococcus aureus. Methods and Results The activity of the standard antibiotics and compounds on reference methicillin-sensitive and resistant strains of S. aureus were determined using the macrodilution broth method. The minimum inhibitory concentration (MIC of the compounds was compared with that of the standard antibiotics. The interaction between any two antimicrobial agents was estimated by calculating the fractional inhibitory concentration (FIC index of the combination. The various combinations of antibiotics and compounds reduced the MIC to a range of 0.05 to 50%. Conclusion Pentacyclic triterpenoids have shown anti-staphylococcal activities and although individually weaker than common antibiotics produced from bacteria and fungi, synergistically these compounds may use different mechanism of action or pathways to exert their antimicrobial effects, as implicated in the lowered MICs. Therefore, the use of current antibiotics could be maintained in their combination with plant-derived antibacterial agents as a therapeutic option in the treatment of S. aureus infections.

  20. Antimicrobial effects of Piper hispidum extract, fractions and chalcones against Candida albicans and Staphylococcus aureus.

    Science.gov (United States)

    Costa, G M; Endo, E H; Cortez, D A G; Nakamura, T U; Nakamura, C V; Dias Filho, B P

    2016-09-01

    Three chalcones, 2'-hydroxy-4,4',6'-trimethoxychalcone, 2'-hydroxy-4,4',6'-tetramethoxychalcone, and 3,2'-dihydroxy-4,4',6'-trimethoxychalcone, were isolated from the leaves of Piper hispidum in a bioguided fractionation of crude extract. The antimicrobial activity of crude extract of P. hispidum leaves was determined against bacteria Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus and yeasts Candida albicans, C. parapsilosis and C. tropicalis. Fractions and chalcones were tested against C. albicans and S. aureus. The checkerboard assay was performed to assess synergic interactions between extract and antifungal drugs, and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) reduction assay was used to evaluate anti-biofilm effects of extract. The extract was active against yeasts, S. aureus and B. subtilis with MIC values between 15.6 and 62.5μg/mL. Synergistic effects of extract associated with fluconazole and nystatin were observed against C. albicans, with fractional inhibitory concentration indices of 0.37 and 0.24, respectively. The extract was also effective against C. albicans and S. aureus biofilm cells at concentrations of 62.5 and 200μg/mL, respectively. Thus, P. hispidum may be a possible source of bioactive substances with antimicrobial properties.

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

    Directory of Open Access Journals (Sweden)

    Joyce Elaine Cristina Betoni

    2006-06-01

    Full Text Available Searches for substances with antimicrobial activity are frequent, and medicinal plants have been considered interesting by some researchers since they are frequently used in popular medicine as remedies for many infectious diseases. The aim of this study was to verify the synergism between 13 antimicrobial drugs and 8 plant extracts - "guaco" (Mikania glomerata, guava (Psidium guajava, clove (Syzygium aromaticum, garlic (Allium sativum, lemongrass (Cymbopogon citratus, ginger (Zingiber officinale, "carqueja" (Baccharis trimera, and mint (Mentha piperita - against Staphylococcus aureus strains, and for this purpose, the disk method was the antimicrobial susceptibility test performed. Petri dishes were prepared with or without dilution of plant extracts at sub-inhibitory concentrations in Mueller-Hinton Agar (MHA, and the inhibitory zones were recorded in millimeters. In vitro anti-Staphylococcus aureus activities of the extracts were confirmed, and synergism was verified for all the extracts; clove, guava, and lemongrass presented the highest synergism rate with antimicrobial drugs, while ginger and garlic showed limited synergistic capacity.

  2. Characterization of Toxin Genes and Antimicrobial Susceptibility of Staphylococcus aureus Isolates in Fishery Products in Iran

    Science.gov (United States)

    Arfatahery, Noushin; Davoodabadi, Abolfazl; Abedimohtasab, Taranehpeimaneh

    2016-01-01

    Staphylococcus aureus is one of the most common causes of seafood-borne diseases worldwide, which are attributable to the contamination of food by preformed enterotoxins. In this study, a total of 206 (34.3%) Staphylococcus aureus strains were obtained from 600 fish and shrimp samples and were tested for their antimicrobial susceptibility. We assessed the prevalence of the genes responsible for the staphylococcal enterotoxins (SEA, SEB) and toxic shock syndrome toxin 1 (TSST-1) genes. The results indicated that 34% of aqua food samples were contaminated with S. aureus, and 23.8% of these isolates were mec-A-positive. Sixty-four percent of the strains isolated from contaminated seafood was enterotoxigenic S. aureus, and 28.2% of SEs were MRSA-positive. The most prevalent genotype was characterized by the presence of the sea gene (45.2%), followed by the seb gene (18.5%), and the tst gene encoding TSST-1 was found in eight strains (3.9%). Of the 206 S. aureus isolates, 189 strains (84.9%) were resistant to at least one antibiotic. Given the frequent outbreaks of enterotoxigenic MRSA, it is necessary to make revisions to mandatory programmes to facilitate improved hygiene practices during fishing, aquaculture, processing, and sales to prevent the contamination of fishery products in Iran. PMID:27694813

  3. Antimicrobial Resistance and Molecular Characteristics of Nasal Staphylococcus aureus Isolates From Newly Admitted Inpatients.

    Science.gov (United States)

    Chen, Xu; Sun, Kangde; Dong, Danfeng; Luo, Qingqiong; Peng, Yibing; Chen, Fuxiang

    2016-05-01

    Staphylococcus aureus, or methicillin-resistant S. aureus (MRSA), is a significant pathogen in both nosocomial and community infections. Community-associated MRSA (CA-MRSA) strains tend to be multi-drug resistant and to invade hospital settings. This study aimed to assess the antimicrobial resistance and molecular characteristicsof nasal S. aureus among newlyadmitted inpatients.In the present study, 66 S. aureus isolates, including 10 healthcare-associated MRSA (HA-MRSA), 8 CA-MRSA, and 48 methicillin-sensitive S. aureus (MSSA) strains, were found in the nasal cavities of 62 patients by screening 292 newlyadmitted patients. Antimicrobial resistance and molecular characteristics of these isolates, including spa-type, sequence type (ST) and SCCmec type, were investigated. All isolates were sensitive to linezolid, teicoplanin, and quinupristin/dalfopristin, but high levels of resistance to penicillin and erythromycin were detected. According to D-test and erm gene detection results, the cMLS(B) and iMLS(B) phenotypes were detected in 24 and 16 isolates, respectively. All 10 HA-MRSA strains displayed the cMLS(B) phenotypemediated by ermA or ermA/ermC, while the cMLS(B) CA-MRSA and MSSA strains carried the ermB gene. Molecular characterization revealedall 10 HA-MRSA strains were derived from the ST239-SCCmec III clone, and four out of eight CA-MRSA strains were t437-ST59-SCCmec V. The results suggest that patients play an indispensable role in transmitting epidemic CA-MRSA and HA-MRSA strains.

  4. Delay in the administration of appropriate antimicrobial therapy in Staphylococcus aureus bloodstream infection : A prospective multicenter hospital-based cohort study

    NARCIS (Netherlands)

    Kaasch, A. J.; Rieg, S.; Kuetscher, J.; Brodt, H. -R.; Widmann, T.; Herrmann, M.; Meyer, C.; Welte, T.; Kern, P.; Haars, U.; Reuter, S.; Huebner, I.; Strauss, R.; Sinha, B.; Brunkhorst, F. M.; Hellmich, M.; Faetkenheuer, G.; Kern, W. V.; Seifert, H.

    2013-01-01

    Early broad-spectrum antimicrobial treatment reduces mortality in patients with septic shock. In a multicenter, prospective observational study, we explored whether delayed appropriate antimicrobial therapy (AAT) influences outcome in Staphylococcus aureus bloodstream infection (SAB). Two hundred an

  5. Cholecalciferol (vitamin D) differentially regulates antimicrobial peptide expression in bovine mammary epithelial cells: implications during Staphylococcus aureus internalization.

    Science.gov (United States)

    Téllez-Pérez, Ana Dolores; Alva-Murillo, Nayeli; Ochoa-Zarzosa, Alejandra; López-Meza, Joel E

    2012-11-09

    Vitamin D has immunomodulatory functions regulating the expression of host defense genes. The aim of this study was to determine the effect of cholecalciferol (vitamin D3) on S. aureus internalization into bovine mammary epithelial cells (bMEC) and antimicrobial peptide (AP) mRNA expression. Cholecalciferol (1-200 nM) did not affect S. aureus growth and bMEC viability; but it reduced bacterial internalization into bMEC (15-74%). Also, bMEC showed a basal expression of all AP genes evaluated, which were induced by S. aureus. Cholecalciferol alone or together with bacteria diminished tracheal antimicrobial peptide (TAP) and bovine neutrophil β-defensin (BNBD) 5 mRNA expression; while alone induced the expression of lingual antimicrobial peptide (LAP), bovine β-defensin 1 (DEFB1) and bovine psoriasin (S100A7), which was inhibited in the presence of S. aureus. This compound (50 nM) increased BNBD10 mRNA expression coinciding with the greatest reduction in S. aureus internalization. Genes of vitamin D pathway (25-hydroxylase and 1 α-hydroxylase) show basal expression, which was induced by cholecalciferol or bacteria. S. aureus induced vitamin D receptor (VDR) mRNA expression, but not in the presence of cholecalciferol. In conclusion, cholecalciferol can reduce S. aureus internalization and differentially regulates AP expression in bMEC. Thus, vitamin D could be an effective innate immunity modulator in mammary gland, which leads to a better defense against bacterial infection.

  6. Phenotypic and genotypic antimicrobial resistance traits of foodborne Staphylococcus aureus isolates from Shanghai.

    Science.gov (United States)

    Xu, Jie; Shi, Chunlei; Song, Minghui; Xu, Xuebin; Yang, Puyu; Paoli, George; Shi, Xianming

    2014-04-01

    Staphylococcus aureus is a recognized pathogen in humans, which causes nosocomial infections and food poisoning. The transmission of antibiotic resistant S. aureus (ARSA), especially methicillin-resistant S. aureus, between food products and humans has become a serious problem. Hence, it is necessary to monitor S. aureus through the food supply chain. In this study, the disk diffusion method and epsilometer test were performed to determine the prevalence of ARSA in 78 foodborne isolates using 18 antibiotics. The highest resistance frequency was found for penicillin G (74.4%), followed by erythromycin (59.0%) and clindamycin (44.9%), whereas no vancomycin-resistant isolates were found. The 78 isolates could be subtyped into 31 resistance profiles and 11 clusters based on their antimicrobial susceptibility. Furthermore, Polymerase chain reaction (PCR) screening for the presence of 13 genes conferring antibiotic resistance was conducted. The presence of resistance genes was relatively high: blaTEM (80.8%), ermB (41.0%), grlA (38.5%), ermC (35.9%), and aac6'/aph2" (35.9%). The incidence of antibiotic resistance was significantly correlated to food types (p = 0.018), with isolates from meat and raw milk more resistant to antibiotics than those from frozen food and vegetables.

  7. New antimicrobial combinations: substituted chalcones- oxacillin against methicillin resistant Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Juan Manuel Talia

    2011-06-01

    Full Text Available Staphylococcus aureus, the most virulent Staphylococcus species, is also the prevalent pathogen isolated from hospitalized patients and the second most common from patients in outpatient settings. In general, bacteria have the genetic ability to transmit and acquire resistance to drugs, which are utilized as therapeutic agents. Related studies of antimicrobial activity indicate that crude extracts containing flavonoids, triterpenes and steroids have showed significative activity against several Staphylococcus aureus strains. Combination effects between flavonoids and antibiotics also have been reported. The aim of the present work was to investigate in vitro synergism between several chalcones substituted in combination with oxacillin, an antibiotic used conventionally against S. aureus ATCC 43 300 that is resistant to meticillin, using the kinetic turbidimetric method developed earlier. The results were satisfactory for all assayed combinations and in accordance with the mechanism of bacteriostatic inhibition previously proposed, except for 2´,4´-dihydroxy-3´-methoxychalcone - oxacillin. The best combination was 2´,3´-dihydroxychalcone - oxacillin (MIC: 11.2 μg/mL. Further investigations are needed to characterize the interaction mechanism with antibiotics. Thus, chalcones - oxacillin combination could lead to the development of new antibiotics against methicillin resistant S. aureus infection.

  8. Antimicrobial resistance and virulence markers in methicillin sensitive Staphylococcus aureus isolates associated with nasal colonization.

    Science.gov (United States)

    Sarkar, Abdullah; Raji, Adeola; Garaween, Ghada; Soge, Olusegun; Rey-Ladino, Jose; Al-Kattan, Wael; Shibl, Atef; Senok, Abiola

    2016-04-01

    Most Staphylococcus aureus infections occur in previously colonized persons who also act as reservoirs for continued dissemination. This study aimed to investigate the carriage of antimicrobial resistance and virulence markers in S. aureus isolates associated with nasal colonization. The study was conducted from December 2013-April 2014. Nasal swabs were collected and questionnaires administered to 97 medical students in Riyadh Saudi Arabia. Bacterial culture, identification and antimicrobial susceptibility testing were performed by conventional methods and chromogenic agar was used for methicillin resistant S. aureus (MRSA) screening. Molecular characterization of isolates was carried out using the StaphyType DNA microarray. Thirty two students (43%) had S. aureus nasal carriage (MSSA = 31; MRSA = 1). Seventeen clonal complexes (CC) were identified namely: CC15-MSSA (n = 5), CC1-MSSA-SCCfus (n = 4), CC8-MSSA (n = 3), CC22-MSSA (n = 3), CC25-MSSA (n = 3), CC101-MSSA (n = 2). Other CC found as single isolates were CC5-MSSA, CC6-MSSA, CC30-MSSA, CC45-MSSA, CC96-MSSA, CC188-MSSA, CC398-MSSA, CC942-MSSA/PVL+, CC1290-MSSA, ST2482-MSSA, CC80-MRSA-IV/PVL+. The CC1-SCCfus isolates harbored the Staphylococcal cassette chromosome (SCC) with ccrA-1; ccrB-1 and ccrB-3 genes plus the putative fusidic acid resistance marker Q6GD50. One MSSA isolate was genotyped as coagulase negative Staphylococcus spp with an irregular composite SCCmec element. Majority of the isolates harbored various virulence genes including the hemolysin, enterotoxin, and exfoliative genes as well as various adhesive protein producing genes. Although there was low carriage of MRSA, the MSSA isolates harbored various resistance and virulence genes including those usually seen in MRSA isolates. The presence of isolates with incomplete SCCmec elements plus putative resistance and virulence genes is of concern.

  9. Antimicrobial food equipment coatings: applications and challenges.

    Science.gov (United States)

    Bastarrachea, Luis J; Denis-Rohr, Anna; Goddard, Julie M

    2015-01-01

    Emerging technologies in antimicrobial coatings can help improve the quality and safety of our food supply. The goal of this review is to survey the major classes of antimicrobial agents explored for use in coatings and to describe the principles behind coating processes. Technologies from a range of fields, including biomedical and textiles research, as well as current applications in food contact materials, are addressed, and the technical hurdles that must be overcome to enable commercial adaptation to food processing equipment are critically evaluated.

  10. Antimicrobial proteins from snake venoms: direct bacterial damage and activation of innate immunity against Staphylococcus aureus skin infection.

    Science.gov (United States)

    Samy, R P; Stiles, B G; Gopalakrishnakone, P; Chow, V T K

    2011-01-01

    The innate immune system is the first line of defense against microbial diseases. Antimicrobial proteins produced by snake venoms have recently attracted significant attention due to their relevance to bacterial infection and potential development into new therapeutic agents. Staphylococcus aureus is one of the major human pathogens causing a variety of infections involving pneumonia, toxic shock syndrome, and skin lesions. With the recent emergence of methicillin (MRSA) and vancomycin (VRSA) resistance, S. aureus infection is a serious clinical problem that will have a grave socio-economic impact in the near future. Although S. aureus susceptibility to innate antimicrobial peptides has been reported recently, the protective effect of snake venom phospholipase A₂ (svPLA₂) proteins on the skin from S. aureus infection has been understudied. This review details the protective function of svPLA₂s derived from venoms against skin infections caused by S. aureus. We have demonstrated in vivo that local application of svPLA₂ provides complete clearance of S. aureus within 2 weeks after treatment compared to fusidic acid ointment (FAO). In vitro experiments also demonstrate that svPLA₂ proteins have inhibitory (bacteriostatic) and killing (bactericidal) effects on S. aureus in a dose-dependant manner. The mechanism of bacterial membrane damage and perturbation was clearly evidenced by electron microscopic studies. In summary, svPLA₂s from Viperidae and Elapidae snakes are novel molecules that can activate important mechanisms of innate immunity in animals to endow them with protection against skin infection caused by S. aureus.

  11. In Vitro Evaluation of the Antimicrobial Efficacy of Four Endodontic Biomaterials against Enterococcus faecalis, Candida albicans, and Staphylococcus aureus

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    Duddi Narendra Nirupama

    2014-01-01

    Full Text Available Root canal sealers that possess good antimicrobial property can prevent residual and recurrent infection and contribute to successful endodontic therapy. This study evaluated the antimicrobial activity of four endodontic sealers, AH Plus, Tubliseal EWT, EndoRez, and iRoot SP, against three different microorganisms, E. faecalis, C. albicans, and S. aureus, by direct contact test. 10 μL microbial suspensions were allowed to directly contact the four endodontic sealers for 1 hr at 37°C. Subsequently microbial growth was measured spectrophotometrically every 30 min for 18 hours. The microbial suspensions were simultaneously tested to determine the antimicrobial effect of components which are capable of diffusing into the medium. The results revealed that AH Plus and iRootSP had significantly higher antimicrobial activity against E. faecalis. AH Plus and Tubliseal EWT showed significantly higher antimicrobial activity against C. albicans and S. aureus compared to iRoot SP and EndoRez. EndoRez showed the least antimicrobial activity against all the three microorganisms. Inhibition of microbial growth is related to the direct contact of microorganisms with the sealers. In conclusion AH Plus had significantly higher antimicrobial activity against E. faecalis, C. albicans, and S. aureus.

  12. Increased survival of experimentally evolved antimicrobial peptide-resistant Staphylococcus aureus in an animal host.

    Science.gov (United States)

    Dobson, Adam J; Purves, Joanne; Rolff, Jens

    2014-09-01

    Antimicrobial peptides (AMPs) have been proposed as new class of antimicrobial drugs, following the increasing prevalence of bacteria resistant to antibiotics. Synthetic AMPs are functional analogues of highly evolutionarily conserved immune effectors in animals and plants, produced in response to microbial infection. Therefore, the proposed therapeutic use of AMPs bears the risk of 'arming the enemy': bacteria that evolve resistance to AMPs may be cross-resistant to immune effectors (AMPs) in their hosts. We used a panel of populations of Staphylococcus aureus that were experimentally selected for resistance to a suite of individual AMPs and antibiotics to investigate the 'arming the enemy' hypothesis. We tested whether the selected strains showed higher survival in an insect model (Tenebrio molitor) and cross-resistance against other antimicrobials in vitro. A population selected for resistance to the antimicrobial peptide iseganan showed increased in vivo survival, but was not more virulent. We suggest that increased survival of AMP-resistant bacteria almost certainly poses problems to immune-compromised hosts.

  13. Molecular basis for the role of Staphylococcus aureus penicillin binding protein 4 in antimicrobial resistance.

    Science.gov (United States)

    Navratna, Vikas; Nadig, Savitha; Sood, Varun; Prasad, K; Arakere, Gayathri; Gopal, B

    2010-01-01

    Penicillin binding proteins (PBPs) are membrane-associated proteins that catalyze the final step of murein biosynthesis. These proteins function as either transpeptidases or carboxypeptidases and in a few cases demonstrate transglycosylase activity. Both transpeptidase and carboxypeptidase activities of PBPs occur at the D-Ala-D-Ala terminus of a murein precursor containing a disaccharide pentapeptide comprising N-acetylglucosamine and N-acetyl-muramic acid-L-Ala-D-Glu-L-Lys-D-Ala-D-Ala. Beta-lactam antibiotics inhibit these enzymes by competing with the pentapeptide precursor for binding to the active site of the enzyme. Here we describe the crystal structure, biochemical characteristics, and expression profile of PBP4, a low-molecular-mass PBP from Staphylococcus aureus strain COL. The crystal structures of PBP4-antibiotic complexes reported here were determined by molecular replacement, using the atomic coordinates deposited by the New York Structural Genomics Consortium. While the pbp4 gene is not essential for the viability of S. aureus, the knockout phenotype of this gene is characterized by a marked reduction in cross-linked muropeptide and increased vancomycin resistance. Unlike other PBPs, we note that expression of PBP4 was not substantially altered under different experimental conditions, nor did it change across representative hospital- or community-associated strains of S. aureus that were examined. In vitro data on purified recombinant S. aureus PBP4 suggest that it is a beta-lactamase and is not trapped as an acyl intermediate with beta-lactam antibiotics. Put together, the expression analysis and biochemical features of PBP4 provide a framework for understanding the function of this protein in S. aureus and its role in antimicrobial resistance.

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

    Science.gov (United States)

    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.

  15. Molecular Characterization and Antimicrobial Resistance Profile of Methicillin-Resistant Staphylococcus aureus in Retail Chicken.

    Science.gov (United States)

    Sallam, Khalid Ibrahim; Abd-Elghany, Samir Mohammed; Elhadidy, Mohamed; Tamura, Tomohiro

    2015-10-01

    The emergence of livestock-associated methicillin-resistant Staphylococcus aureus (MRSA) in food-producing animals is of increasing interest, raising questions about the presence of MRSA in food of animal origin and potential sources of transmission to humans via the food chain. In this study, the prevalence, molecular characterization, virulence factors, and antimicrobial susceptibility patterns of MRSA isolates from 200 retail raw chicken samples in Egypt were determined. MRSA was detected by positive amplification of the mecA gene in 38% (76 of 200) of chicken samples analyzed. This represents a potential public health threat in Egypt, as this contamination rate seems to be the highest among other studies reported worldwide. Furthermore, genes encoding α-hemolysin (hla) and staphylococcal enterotoxins (sea, seb, and sec) were detected in all of the 288 MRSA isolates. Nonetheless, none of the strains tested carried tst, the gene encoding toxic shock syndrome toxin 1. Antimicrobial resistance of MRSA isolates was most frequently detected against penicillin (93.4%), ampicillin (88.9%), and cloxacillin (83.3%). These results suggest that retail chicken might be a significant potential source for transmission of multidrug-resistant and toxigenic S. aureus in Egypt. This underlines the need for stricter hygienic measures in chicken production in Egypt to minimize the risk of transmission of these strains to consumers. To the best of our knowledge, this is the first study that reports the isolation and molecular characterization of MRSA in retail chicken samples in Egypt.

  16. In vivo killing of Staphylococcus aureus using a light-activated antimicrobial agent

    Science.gov (United States)

    2009-01-01

    Background The widespread problem of antibiotic resistance in pathogens such as Staphylococcus aureus has prompted the search for new antimicrobial approaches. In this study we report for the first time the use of a light-activated antimicrobial agent, methylene blue, to kill an epidemic methicillin-resistant Staphylococcus aureus (EMRSA-16) strain in two mouse wound models. Results Following irradiation of wounds with 360 J/cm2 of laser light (670 nm) in the presence of 100 μg/ml of methylene blue, a 25-fold reduction in the number of viable EMRSA was seen. This was independent of the increase in temperature of the wounds associated with the treatment. Histological examination of the wounds revealed no difference between the photodynamic therapy (PDT)-treated wounds and the untreated wounds, all of which showed the same degree of inflammatory infiltration at 24 hours. Conclusion The results of this study demonstrate that PDT is effective at reducing the total number of viable EMRSA in a wound. This approach has promise as a means of treating wound infections caused by antibiotic-resistant microbes as well as for the elimination of such organisms from carriage sites. PMID:19193212

  17. In vivo killing of Staphylococcus aureus using a light-activated antimicrobial agent

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    Bennett Jon

    2009-02-01

    Full Text Available Abstract Background The widespread problem of antibiotic resistance in pathogens such as Staphylococcus aureus has prompted the search for new antimicrobial approaches. In this study we report for the first time the use of a light-activated antimicrobial agent, methylene blue, to kill an epidemic methicillin-resistant Staphylococcus aureus (EMRSA-16 strain in two mouse wound models. Results Following irradiation of wounds with 360 J/cm2 of laser light (670 nm in the presence of 100 μg/ml of methylene blue, a 25-fold reduction in the number of viable EMRSA was seen. This was independent of the increase in temperature of the wounds associated with the treatment. Histological examination of the wounds revealed no difference between the photodynamic therapy (PDT-treated wounds and the untreated wounds, all of which showed the same degree of inflammatory infiltration at 24 hours. Conclusion The results of this study demonstrate that PDT is effective at reducing the total number of viable EMRSA in a wound. This approach has promise as a means of treating wound infections caused by antibiotic-resistant microbes as well as for the elimination of such organisms from carriage sites.

  18. An international multicenter study of antimicrobial consumption and resistance in Staphylococcus aureus isolates from 15 hospitals in 14 countries

    DEFF Research Database (Denmark)

    Westh, Henrik Torkil; Zinn, Christina Scheel; Rosdahl, Vibeke Thamdrup

    2004-01-01

    Antibiotic consumption during 1996 was measured in 15 large hospitals from 14 countries and 3000 consecutive Staphylococcus aureus samples were collected, allowing calculation of local resistance rates and typing of isolates. Antibiotic consumption data were converted to defined daily doses (DDD...... to consumption of aminoglycosides, quinolones, and glycopeptides. In this study of hospitals with MRSA prevalence of between 0% and 63%, significant correlations were found between resistance and consumption of antimicrobials. These findings support the importance of antimicrobial consumption on resistance...

  19. An international multicenter study of antimicrobial consumption and resistance in Staphylococcus aureus isolates from 15 hospitals in 14 countries

    DEFF Research Database (Denmark)

    Westh, Henrik Torkil; Zinn, Christina Scheel; Rosdahl, Vibeke Thamdrup

    2004-01-01

    of therapeutical subgroups of antimicrobials varied significantly between hospitals. A positive correlation was found between S. aureus resistance to methicillin (MRSA) and consumption of beta-lactam combinations, between resistance to quinolones and consumption of beta-lactam combinations and carbapenems...... and resistance to aminoglycosides and consumption of beta-lactam combinations. The consumption of beta-lactamase-sensitive antibiotics was negatively correlated to resistance to methicillin, quinolones, and aminoglycosides. Usage of the different antimicrobial therapeutical subgroups was also correlated...

  20. Novel light-activated antimicrobial coatings are effective against surface-deposited Staphylococcus aureus.

    Science.gov (United States)

    Decraene, Valérie; Pratten, Jonathan; Wilson, Michael

    2008-10-01

    Aerosols constitute a major route of transmission for a wide range of infectious diseases in the hospital setting. The aim of this study was to determine the survival of Staphylococcus aureus on a light-activated antimicrobial coating. S. aureus suspended in phosphate-buffered saline (PBS), saliva, or horse serum was sprayed onto cellulose acetate coatings containing toluidine blue O and rose bengal and the survival of the organism on these surfaces was determined following 6 h of exposure to a 28-W domestic fluorescent lamp (light intensity = 3700 +/- 20 lux). Kills ranging from 78.9% (in horse serum) to 99.8% (in PBS) were obtained when the bacterial density on the coatings was approximately 10(5) colony-forming units/m(2). The results of this study have shown that a coating containing toluidine blue and rose bengal can achieve significant kills of S. aureus when illuminated by a domestic light source. Light-activated coatings could provide a simple, low-cost means of reducing the microbial load in hospitals and other facilities.

  1. Zinc ascorbate has superoxide dismutase-like activity and in vitro antimicrobial activity against Staphylococcus aureus and Escherichia coli

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    Iinuma K

    2012-09-01

    Full Text Available Katsuhiro Iinuma, Isami TsuboiBML General Laboratory, Kawagoe, Saitama, JapanBackground: Acne vulgaris is a common dermatological disease, and its pathogenesis is multifactorial.Objective: We examined whether the ascorbic acid derivative zinc ascorbate has superoxide dismutase (SOD-like activity. SOD is an enzyme that controls reactive oxygen species production. In addition, the in vitro antimicrobial activity of zinc ascorbate against the Gram-positive bacterium Staphylococcus aureus and the Gram-negative bacterium Escherichia coli was tested either alone or in combination with a variety of antimicrobial agents; their fractional inhibitory concentration index was determined using checkerboard tests.Methods: The SOD-like activity was measured in comparison with other ascorbic acid derivatives (ascorbic acid, magnesium ascorbyl phosphate, and sodium ascorbyl phosphate and zinc. The antimicrobial susceptibility of twelve strains each of S. aureus and E. coli isolated from patients with dermatological infections was tested, in comparison to a type strain of S. aureus and E. coli.Results: Zinc ascorbate had significant (P < 0.001 SOD-like activity compared with other ascorbic acid derivatives and zinc. Moreover, it showed antimicrobial activity against a type strain of S. aureus and E. coli, and its concentration (0.064% and 0.128% for S. aureus and E. coli, respectively was sufficiently lower than the normal dose (5% of other ascorbic acid derivatives. Furthermore, combinations of zinc ascorbate with clindamycin, erythromycin, and imipenem against S. aureus (average fractional inhibitory concentration, 0.59–0.90, and with imipenem against E. coli (average fractional inhibitory concentration, 0.64 isolated from patients with dermatological infections showed an additive effect.Conclusions: Our results provide novel evidence that zinc ascorbate may be effective for acne treatment.Keywords: superoxide dismutase, reactive oxygen species, antimicrobial

  2. Antimicrobial susceptibility, virulence genes, and randomly amplified polymorphic DNA analysis of Staphylococcus aureus recovered from bovine mastitis in Ningxia, China.

    Science.gov (United States)

    Wang, Dong; Zhang, Limei; Zhou, Xuezhang; He, Yulong; Yong, Changfu; Shen, Mingliang; Szenci, Otto; Han, Bo

    2016-12-01

    Staphylococcus aureusis the leading pathogen involved inbovine mastitis, but knowledgeabout antimicrobial resistance, virulence factors, and genotypes of Staphylococcus aureus resulting in bovine mastitis in Ningxia, China, is limited. Therefore, antimicrobial susceptibility, virulence gene, and randomly amplified polymorphic DNA (RAPD) analyses of Staph. aureus were carried out. A total of 327 milk samples from cows with clinical and subclinical mastitis in 4 regions of Ningxia were used for the isolation and identification of pathogens according to phenotypic and molecular characteristics. Antimicrobial susceptibility against 22 antimicrobial agents was determined by disk diffusion. The presence of 8 virulence genes in Staph. aureus isolates was tested by PCR. Genotypes of isolates were investigated based on RAPD. Results showed that 35 isolates obtained from mastitis milk samples were identified as Staph. aureus. The isolates were resistant to sulfamethoxazole (100%), penicillin G (94.3%), ampicillin (94.3%), erythromycin (68.6%), azithromycin (68.6%), clindamycin (25.7%), amoxicillin (11.4%), and tetracycline (5.7%). All of the isolates contained one or more virulence genes with average (standard deviation) of 6.6±1.6. The most prevalent virulence genes were hlb (97.1%), followed by fnbpA, hla, coa (94.3% each), nuc (85.7%), fnbpB (80%), clfA (77.1%), and tsst-1 (40%). Nine different gene patterns were found and 3 of them were the dominant gene combinations (77.1%). Staphylococcus aureus isolates (n=35) were divided into 6 genotypes by RAPD tying, the genotypes III and VI were the most prevalent genotypes. There was greatvariation in genotypes of Staph. aureus isolates, not only among different farms, but also within the same herd in Ningxia province. The study showed a high incidence of Staph. aureus with genomic variation of resistance genes, which is matter of great concern in public and animal health in Ningxia province of China.

  3. Incidence, Antimicrobial Susceptibility, and Toxin Genes Possession Screening of Staphylococcus aureus in Retail Chicken Livers and Gizzards

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    Lubna S. Abdalrahman

    2015-04-01

    Full Text Available Few recent outbreaks in Europe and the US involving Campylobacter and Salmonella were linked to the consumption of chicken livers. Studies investigating Staphylococcus aureus in chicken livers and gizzards are very limited. The objectives of this study were to determine the prevalence, antimicrobial resistance, and virulence of S. aureus and MRSA (Methicillin-Resistant Staphylococcus aureus in retail chicken livers and gizzards in Tulsa, Oklahoma. In this study, 156 chicken livers and 39 chicken gizzards samples of two brands were collected. While one of the brands showed very low prevalence of 1% (1/100 for S. aureus in chicken livers and gizzards, the second brand showed prevalence of 37% (31/95. No MRSA was detected since none harbored the mecA or mecC gene. Eighty seven S. aureus isolates from livers and 28 from gizzards were screened for antimicrobial resistance to 16 antimicrobials and the possession of 18 toxin genes. Resistance to most of the antimicrobials screened including cefoxitin and oxacillin was higher in the chicken gizzards isolates. While the prevalence of enterotoxin genes seg and sei was higher in the gizzards isolates, the prevalence of hemolysin genes hla, hlb, and hld was higher in the livers ones. The lucocidin genes lukE-lukD was equally prevalent in chicken livers and gizzards isolates. Using spa typing, a subset of the recovered isolates showed that they are not known to be livestock associated and, hence, may be of a human origin. In conclusion, this study stresses the importance of thorough cooking of chicken livers and gizzards since it might contain multidrug resistant enterotoxigenic S. aureus. To our knowledge this is the first study to specifically investigate the prevalence of S. aureus in chicken livers and gizzards in the US.

  4. Antimicrobial Resistance Profile of Planktonic and Biofilm Cells of Staphylococcus aureus and Coagulase-Negative Staphylococci

    Science.gov (United States)

    de Oliveira, Adilson; Cataneli Pereira, Valéria; Pinheiro, Luiza; Moraes Riboli, Danilo Flávio; Benini Martins, Katheryne; Ribeiro de Souza da Cunha, Maria de Lourdes

    2016-01-01

    The objective of the present study was to determine the antimicrobial resistance profile of planktonic and biofilm cells of Staphylococcus aureus and coagulase-negative staphylococci (CoNS). Two hundred Staphylococcus spp. strains were studied, including 50 S. aureus and 150 CoNS strains (50 S. epidermidis, 20 S. haemolyticus, 20 S. warneri, 20 S. hominis, 20 S. lugdunensis, and 20 S. saprophyticus). Biofilm formation was investigated by adherence to polystyrene plates. Positive strains were submitted to the broth microdilution method to determine the minimum inhibitory concentration (MIC) for planktonic and biofilm cells and the minimal bactericidal concentration for biofilm cells (MBCB). Forty-nine Staphylococcus spp. strains (14 S. aureus, 13 S. epidermidis, 13 S. saprophyticus, 3 S. haemolyticus, 1 S. hominis, 3 S. warneri, and 2 S. lugdunensis) were biofilm producers. These isolates were evaluated regarding their resistance profile. Determination of planktonic cell MIC identified three (21.4%) S. aureus strains that were resistant to oxacillin and six (42.8%) that were resistant to erythromycin. Among the CoNS, 31 (88.6%) strains were resistant to oxacillin, 14 (40%) to erythromycin, 18 (51.4%) to gentamicin, and 8 (22.8%) to sulfamethoxazole/trimethoprim. None of the planktonic isolates were resistant to vancomycin or linezolid. MICs were 2-, 4-, 8-, and up to 16-fold higher for biofilm cells than for planktonic cells. This observation was more common for vancomycin and erythromycin. The MBCB ranged from 8 to >256 µg/mL for oxacillin, 128 to >128 µg/mL for vancomycin, 256 to >256 µg/mL for erythromycin and gentamicin, >64 µg/mL for linezolid, and 32/608 to >32/608 µg/mL for sulfamethoxazole/trimethoprim. The results showed considerably higher MICs for S. aureus and CoNS biofilm cells compared to planktonic cells. Analysis of MBCM confirmed that even high concentrations of vancomycin were unable to eliminate the biofilms of S. aureus and CoNS species

  5. Antimicrobial Resistance Profile of Planktonic and Biofilm Cells of Staphylococcus aureus and Coagulase-Negative Staphylococci.

    Science.gov (United States)

    de Oliveira, Adilson; Cataneli Pereira, Valéria; Pinheiro, Luiza; Moraes Riboli, Danilo Flávio; Benini Martins, Katheryne; Ribeiro de Souza da Cunha, Maria de Lourdes

    2016-09-01

    The objective of the present study was to determine the antimicrobial resistance profile of planktonic and biofilm cells of Staphylococcus aureus and coagulase-negative staphylococci (CoNS). Two hundred Staphylococcus spp. strains were studied, including 50 S. aureus and 150 CoNS strains (50 S. epidermidis, 20 S. haemolyticus, 20 S. warneri, 20 S. hominis, 20 S. lugdunensis, and 20 S. saprophyticus). Biofilm formation was investigated by adherence to polystyrene plates. Positive strains were submitted to the broth microdilution method to determine the minimum inhibitory concentration (MIC) for planktonic and biofilm cells and the minimal bactericidal concentration for biofilm cells (MBCB). Forty-nine Staphylococcus spp. strains (14 S. aureus, 13 S. epidermidis, 13 S. saprophyticus, 3 S. haemolyticus, 1 S. hominis, 3 S. warneri, and 2 S. lugdunensis) were biofilm producers. These isolates were evaluated regarding their resistance profile. Determination of planktonic cell MIC identified three (21.4%) S. aureus strains that were resistant to oxacillin and six (42.8%) that were resistant to erythromycin. Among the CoNS, 31 (88.6%) strains were resistant to oxacillin, 14 (40%) to erythromycin, 18 (51.4%) to gentamicin, and 8 (22.8%) to sulfamethoxazole/trimethoprim. None of the planktonic isolates were resistant to vancomycin or linezolid. MICs were 2-, 4-, 8-, and up to 16-fold higher for biofilm cells than for planktonic cells. This observation was more common for vancomycin and erythromycin. The MBCB ranged from 8 to >256 µg/mL for oxacillin, 128 to >128 µg/mL for vancomycin, 256 to >256 µg/mL for erythromycin and gentamicin, >64 µg/mL for linezolid, and 32/608 to >32/608 µg/mL for sulfamethoxazole/trimethoprim. The results showed considerably higher MICs for S. aureus and CoNS biofilm cells compared to planktonic cells. Analysis of MBCM confirmed that even high concentrations of vancomycin were unable to eliminate the biofilms of S. aureus and CoNS species

  6. Antimicrobial Resistance Profile of Planktonic and Biofilm Cells of Staphylococcus aureus and Coagulase-Negative Staphylococci

    Directory of Open Access Journals (Sweden)

    Adilson de Oliveira

    2016-09-01

    Full Text Available The objective of the present study was to determine the antimicrobial resistance profile of planktonic and biofilm cells of Staphylococcus aureus and coagulase-negative staphylococci (CoNS. Two hundred Staphylococcus spp. strains were studied, including 50 S. aureus and 150 CoNS strains (50 S. epidermidis, 20 S. haemolyticus, 20 S. warneri, 20 S. hominis, 20 S. lugdunensis, and 20 S. saprophyticus. Biofilm formation was investigated by adherence to polystyrene plates. Positive strains were submitted to the broth microdilution method to determine the minimum inhibitory concentration (MIC for planktonic and biofilm cells and the minimal bactericidal concentration for biofilm cells (MBCB. Forty-nine Staphylococcus spp. strains (14 S. aureus, 13 S. epidermidis, 13 S. saprophyticus, 3 S. haemolyticus, 1 S. hominis, 3 S. warneri, and 2 S. lugdunensis were biofilm producers. These isolates were evaluated regarding their resistance profile. Determination of planktonic cell MIC identified three (21.4% S. aureus strains that were resistant to oxacillin and six (42.8% that were resistant to erythromycin. Among the CoNS, 31 (88.6% strains were resistant to oxacillin, 14 (40% to erythromycin, 18 (51.4% to gentamicin, and 8 (22.8% to sulfamethoxazole/trimethoprim. None of the planktonic isolates were resistant to vancomycin or linezolid. MICs were 2-, 4-, 8-, and up to 16-fold higher for biofilm cells than for planktonic cells. This observation was more common for vancomycin and erythromycin. The MBCB ranged from 8 to >256 µg/mL for oxacillin, 128 to >128 µg/mL for vancomycin, 256 to >256 µg/mL for erythromycin and gentamicin, >64 µg/mL for linezolid, and 32/608 to >32/608 µg/mL for sulfamethoxazole/trimethoprim. The results showed considerably higher MICs for S. aureus and CoNS biofilm cells compared to planktonic cells. Analysis of MBCM confirmed that even high concentrations of vancomycin were unable to eliminate the biofilms of S. aureus and Co

  7. Isolation, Virulence, and Antimicrobial Resistance of Methicillin-Resistant Staphylococcus aureus (MRSA) and Methicillin Sensitive Staphylococcus aureus (MSSA) Strains from Oklahoma Retail Poultry Meats.

    Science.gov (United States)

    Abdalrahman, Lubna S; Stanley, Adriana; Wells, Harrington; Fakhr, Mohamed K

    2015-05-29

    Staphylococcus aureus is one the top five pathogens causing domestically acquired foodborne illness in the U.S. Only a few studies are available related to the prevalence of S. aureus and MRSA in the U.S. retail poultry industry. The objectives of this study were to determine the prevalence of S. aureus (MSSA and MRSA) in retail chicken and turkey meats sold in Tulsa, Oklahoma and to characterize the recovered strains for their antimicrobial resistance and possession of toxin genes. A total of 167 (114 chicken and 53 turkey) retail poultry samples were used in this study. The chicken samples included 61 organic samples while the rest of the poultry samples were conventional. The overall prevalence of S. aureus was 57/106 (53.8%) in the conventional poultry samples and 25/61 (41%) in the organic ones. Prevalence in the turkey samples (64.2%) was higher than in the chicken ones (42.1%). Prevalence of S. aureus did not vary much between conventional (43.4%) and organic chicken samples (41%). Two chicken samples 2/114 (1.8%) were positive for MRSA. PFGE identified the two MRSA isolates as belonging to PFGE type USA300 (from conventional chicken) and USA 500 (from organic chicken) which are community acquired CA-MRSA suggesting a human based source of contamination. MLST and spa typing also supported this conclusion. A total of 168 Staphylococcus aureus isolates (101 chicken isolates and 67 turkey isolates) were screened for their antimicrobial susceptibility against 16 antimicrobials and their possession of 18 different toxin genes. Multidrug resistance was higher in the turkey isolates compared to the chicken ones and the percentage of resistance to most of the antimicrobials tested was also higher among the turkey isolates. The hemolysin hla and hld genes, enterotoxins seg and sei, and leucocidins lukE-lukD were more prevalent in the chicken isolates. The PVL gene lukS-lukF was detected only in chicken isolates including the MRSA ones. In conclusion, S. aureus is

  8. An Evaluation of the Antimicrobial Synergy of Garlic (Allium sativum and Utazi (Gongronema latifolium on Escherichia coli and Staphylococcus aureus

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    Eja, M. E.

    2011-01-01

    Full Text Available As part of the on-going search for potent and resistance-free antimicrobial medicinal plants, the antimicrobial and synergistic effects of the plants, Allium sativum (E1 and Gongronema latifolium (E2 on Escherichia coli and Staphylococcus aureus were investigated. The sensitivities of E. coli and S. aureus to E1 and E2 and the minimum inhibitory concentrations of the plant extracts, individually and in combination with themselves, and with ciprofloxacin (CPX and ampicillin (AMP, were tested using standard procedures. E1 and E2 individually showed appreciable antimicrobial effect (zones of inhibition > 16mm. The combination of E1 and E2 against the test organisms was not effective due to antagonism between E1 and E2. E1 or E2 when combined with CPX, completely suppressed the effect of CPX against E. coli, and rather produced additive effect on S. aureus similar to the combination of E2 and AMP against S. aureus, although CPX alone was more effective than either E1 or E2, unlike AMP. Synergism was observed in the combination of E1 and AMP against S. aureus. It is concluded that synergism associated with the combination of medicinal plants is doubtful. However, the synergistic or additive effect between garlic and conventional drugs to some strains of bacteria which are resistant to some conventional drugs, gives hope of fighting drug resistance.

  9. Comparison of antimicrobial resistance in Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes strains isolated from organic and conventional poultry meat.

    Science.gov (United States)

    Miranda, J M; Vázquez, B I; Fente, C A; Calo-Mata, P; Cepeda, A; Franco, C M

    2008-12-01

    The presence of Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes was determined in 55 samples of organic poultry meat and in 61 samples of conventional poultry meat. A total of 220 E. coli, 192 S. aureus, and 71 L. monocytogenes strains were analyzed by an agar disk diffusion assay for their resistance to ampicillin, cephalothin, chloramphenicol, ciprofloxacin, doxycycline, fosfomycin, gentamicin, nitrofurantoin, streptomycin, and sulfisoxazole (E. coli); chloramphenicol, ciprofloxacin, clindamycin, doxycycline, erythromycin, gentamicin, nitrofurantoin, oxacillin, and sulfisoxazole (S. aureus); and chloramphenicol, doxycycline, erythromycin, gentamicin, sulfisoxazole, and vancomycin (L. monocytogenes). The results indicated a significantly higher (P poultry meat as compared with conventional poultry meat. E. coli isolated from organic poultry meat exhibited lower levels of antimicrobial resistance against 7 of the 10 antimicrobials tested as compared with isolates recovered from conventional meat. In the case of S. aureus and L. monocytogenes isolated from conventional poultry, antimicrobial resistance was significantly higher only for doxycycline as compared with strains isolated from organic poultry. In the case of E. coli, the presence of multiresistant strains was significantly higher (P poultry meat as compared with organic poultry meat. Organically farmed poultry samples showed significantly lower development of antimicrobial resistance in intestinal bacteria such as E. coli.

  10. Prevalence and antimicrobial susceptibility pattern of methicillin resistant Staphylococcus aureus isolates from Trinidad & Tobago

    Directory of Open Access Journals (Sweden)

    Monteil Michele

    2006-07-01

    Full Text Available Abstract Background Methicillin-resistant Staphylococcus aureus (MRSA has become increasingly prevalent worldwide since it was first reported in a British hospital. The prevalence however, varies markedly in hospitals in the same country, and from one country to another. We therefore sought to document comprehensively the prevalence and antimicrobial susceptibility pattern of MRSA isolates in Trinidad and Tobago. Methods All Staphylococcus aureus isolates encountered in routine clinical specimens received at major hospitals in the country between 2000 and 2001 were identified morphologically and biochemically by standard laboratory procedures including latex agglutination test (Staphaurex Plus; Murex Diagnostics Ltd; Dartford, England; tube coagulase test with rabbit plasma (Becton, Dickinson & Co; Sparks, MD, USA, and DNase test using DNase agar (Oxoid Ltd; Basingstoke, Hampshire, England. MRSA screening was performed using Mueller-Hinton agar containing 6 μg oxacillin and 4% NaCl, latex agglutination test (Denka Seiken Co. Ltd, Tokyo, Japan and E-test system (AB Biodisk, Solna, Sweden. Susceptibility to antimicrobial agents was determined by the modified Kirby Bauer disc diffusion method while methicillin MICs were determined with E-test system. Results Of 1,912 S. aureus isolates received, 12.8% were methicillin (oxacillin resistant. Majority of the isolates were recovered from wound swabs (86.9% and the least in urine (0.4% specimens. Highest number of isolates was encountered in the surgical (62.3% and the least from obstetrics and gynaecology (1.6% facilities respectively. Large proportions of methicillin sensitive isolates are >85% sensitive to commonly used and available antimicrobials in the country. All MRSA isolates were resistant to ceftriaxone, erythromycin, gentamicin and penicillin but were 100% sensitive to vancomycin, rifampin and chloramphenicol. Conclusion There is a progressive increase in MRSA prevalence in the country but

  11. Amphibian antimicrobial peptide fallaxin analogue FL9 affects virulence gene expression and DNA replication in Staphylococcus aureus.

    Science.gov (United States)

    Gottschalk, Sanne; Gottlieb, Caroline T; Vestergaard, Martin; Hansen, Paul R; Gram, Lone; Ingmer, Hanne; Thomsen, Line E

    2015-12-01

    The rapid rise in antibiotic-resistant pathogens is causing increased health concerns, and consequently there is an urgent need for novel antimicrobial agents. Antimicrobial peptides (AMPs), which have been isolated from a wide range of organisms, represent a very promising class of novel antimicrobials. In the present study, the analogue FL9, based on the amphibian AMP fallaxin, was studied to elucidate its mode of action and antibacterial activity against the human pathogen Staphylococcus aureus. Our data showed that FL9 may have a dual mode of action against S. aureus. At concentrations around the MIC, FL9 bound DNA, inhibited DNA synthesis and induced the SOS DNA damage response, whereas at concentrations above the MIC the interaction between S. aureus and FL9 led to membrane disruption. The antibacterial activity of the peptide was maintained over a wide range of NaCl and MgCl(2) concentrations and at alkaline pH, while it was compromised by acidic pH and exposure to serum. Furthermore, at subinhibitory concentrations of FL9, S. aureus responded by increasing the expression of two major virulence factor genes, namely the regulatory rnaIII and hla, encoding α-haemolysin. In addition, the S. aureus-encoded natural tolerance mechanisms included peptide cleavage and the addition of positive charge to the cell surface, both of which minimized the antimicrobial activity of FL9. Our results add new information about FL9 and its effect on S. aureus, which may aid in the future development of analogues with improved therapeutic potential.

  12. Antimicrobial activity of zinc oxide particles on five micro-organisms of the Challenge Tests related to their physicochemical properties.

    Science.gov (United States)

    Pasquet, Julia; Chevalier, Yves; Couval, Emmanuelle; Bouvier, Dominique; Noizet, Gaëlle; Morlière, Cécile; Bolzinger, Marie-Alexandrine

    2014-01-02

    Zinc oxide is commonly used in pharmaceutical products to prevent or treat topical or systemic diseases owing to its antimicrobial properties, but it is scarcely used as preservative in topical formulations. The aim of this work was to investigate the antimicrobial activity of zinc oxide (ZnO) powders on the five microbial strains used for Challenge Tests in order to evaluate this inorganic compound as a preservative in topical formulation and assess relationships between the structural parameters of ZnO particles and their antimicrobial activity. For this purpose, the physicochemical characteristics of three ZnO grades were measured and their antimicrobial efficacy against the following micro-organisms - Escherichia coli; Staphylococcus aureus; Pseudomonas aeruginosa; Candida albicans; Aspergillus brasiliensis - was assessed using disc diffusion susceptibility tests and a broth dilution method. The comprehensive dataset of physicochemical characteristics and antimicrobial activities (MIC and MBC) is discussed regarding methodological issues related to the particulate nature of ZnO and structure-activity relationships. Every ZnO grade showed bactericidal and antifungal activity against the five tested micro-organisms in a concentration dependent manner. ZnO particles with smaller size, larger specific area and higher porosity exhibit higher antimicrobial activity. Such trends are related to their mechanisms of antimicrobial activity.

  13. Comparing selection on S. aureus between antimicrobial peptides and common antibiotics.

    Science.gov (United States)

    Dobson, Adam J; Purves, Joanne; Kamysz, Wojciech; Rolff, Jens

    2013-01-01

    With a diminishing number of effective antibiotics, there has been interest in developing antimicrobial peptides (AMPs) as drugs. However, any new drug faces potential bacterial resistance evolution. Here, we experimentally compare resistance evolution in Staphylococcus aureus selected by three AMPs (from mammals, amphibians and insects), a combination of two AMPs, and two antibiotics: the powerful last-resort vancomycin and the classic streptomycin. We find that resistance evolves readily against single AMPs and against streptomycin, with no detectable fitness cost. However the response to selection from our combination of AMPs led to extinction, in a fashion qualitatively similar to vancomycin. This is consistent with the hypothesis that simultaneous release of multiple AMPs during immune responses is a factor which constrains evolution of AMP resistant pathogens.

  14. Comparing selection on S. aureus between antimicrobial peptides and common antibiotics.

    Directory of Open Access Journals (Sweden)

    Adam J Dobson

    Full Text Available With a diminishing number of effective antibiotics, there has been interest in developing antimicrobial peptides (AMPs as drugs. However, any new drug faces potential bacterial resistance evolution. Here, we experimentally compare resistance evolution in Staphylococcus aureus selected by three AMPs (from mammals, amphibians and insects, a combination of two AMPs, and two antibiotics: the powerful last-resort vancomycin and the classic streptomycin. We find that resistance evolves readily against single AMPs and against streptomycin, with no detectable fitness cost. However the response to selection from our combination of AMPs led to extinction, in a fashion qualitatively similar to vancomycin. This is consistent with the hypothesis that simultaneous release of multiple AMPs during immune responses is a factor which constrains evolution of AMP resistant pathogens.

  15. Nanoparticle-mediated delivery of the antimicrobial peptide plectasin against Staphylococcus aureus in infected epithelial cells

    DEFF Research Database (Denmark)

    Water, Jorrit Jeroen; Smart, Simon; Franzyk, Henrik

    2015-01-01

    intracellularly in Calu-3 epithelial cells and in THP-1 cells, whereas A549 cells did not show significant uptake of nanoparticles. Overall, encapsulation of plectasin into PLGA-based nanoparticles appears to be a viable strategy to improve the efficacy of plectasin against infections in epithelial tissues....... epithelial cells might thus be a promising approach to combat such infections. In this work, plectasin, which is a cationic AMP of the defensin class, was encapsulated into poly(lactic-co-glycolic acid) (PLGA) nanoparticles using the double emulsion solvent evaporation method. The nanoparticles displayed...... high plectasin encapsulation efficiency (71-90%) and mediated release of the peptide over 24h. The antimicrobial efficacy of the peptide-loaded nanoparticles was investigated using bronchiolar epithelial Calu-3 cell monolayers infected with S. aureus. The plectasin-loaded nanoparticles displayed...

  16. Antimicrobial peptide exposure selects for Staphylococcus aureus resistance to human defence peptides

    DEFF Research Database (Denmark)

    Kubicek-Sutherland, Jessica Z.; Lofton, Hava; Vestergaard, Martin;

    2016-01-01

    Background: The clinical development of antimicrobial peptides (AMPs) is currently under evaluation to combat the rapid increase in MDR bacterial pathogens. However, many AMPs closely resemble components of the human innate immune system and the ramifications of prolonged bacterial exposure to AMPs...... suggest that therapeutic use of AMPs could select for virulent mutants with crossresistance to human innate immunity as well as antibiotic therapy. Thus, therapeutic use of AMPs and the implications of cross-resistance need to be carefully monitored and evaluated....... of sepsis. Results: AMP-resistant Staphylococcus aureus mutants often displayed little to no fitness cost and caused invasive disease in mice. Further, this phenotype coincided with diminished susceptibility to both clinically prescribed antibiotics and human defence peptides. Conclusions: These findings...

  17. Photodynamic Antimicrobial Chemotherapy (PACT) in osteomyelitis induced by Staphylococcus aureus: Microbiological and histological study.

    Science.gov (United States)

    Dos Reis, João Alves; Dos Santos, Jean Nunes; Barreto, Brunna Santos; de Assis, Patrícia Nascimento; Almeida, Paulo Fernando; Pinheiro, Antônio Luiz Barbosa

    2015-08-01

    Osteomyelitis is an inflammation either of medullar spaces or of the surface of cortical bones, which represents a bacterial infection. Photodynamic Antimicrobial Chemotherapy (PACT) is a treatment based on a cytotoxic photochemical reaction that induces a series of metabolic reactions and culminates in bacterial suppression. Such effect led to the idea that it could be used as a treatment of osteomyelitis. Following approval by the Animal Experimentation Committee of the School of Dentistry of the Federal University of Bahia, the present randomized study used eighty Wistar rats with the aim to evaluate, by microbiological and histological analysis, the effects of Photodynamic Antimicrobial Chemotherapy - PACT on tibial surgical bone defects in rats infected by Staphylococcus aureus. The animals were divided in groups: Control (non-infected); Control Osteomyelitis Induction; Saline solution; Photosensitizer; Red Laser and PACT - on this group, a diode laser (40mW; λ660nm ∅=0.04cm(2), CW, 10J/cm(2)) was used in combination with 5μg/ml of toluidine blue as the photosensitizer. On the microbiological study, immediately after treatment, the PACT group presented a bacterial reduction of 97.4% (p<0.001). Thirty days after treatment, there was a bacterial reduction of more than 99.9% (p<0.001). In the histological study, it was observed that the PACT group demonstrated an intense presence of osteocytes and absence of bone sequestration and micro-abscesses. The PACT using toluidine blue was effective in reducing the number of S. aureus enabling a better quality bone repair.

  18. Antimicrobial resistance and mecA characterization of methicillin-susceptible S. aureus and non-S. aureus of beef meat origin in Egypt

    Directory of Open Access Journals (Sweden)

    Kamelia Mahmoud Osman

    2016-02-01

    Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA have been found in various farm animal species throughout the world. Yet, methicillin-susceptible S. aureus (MSSA, methicillin-susceptible non-S. aureus (MS-NSA and methicillin-resistant non-S. aureus (MR-NSA were not investigated. Therefore, we persued to determine the diversity in theirphenotypic virulence assay, phenotypic antimicrobial resistance profile and molecular characterisation in one of the food chains in Egypt. Samples were collected during 2013 from beef meat at retail. Twenty seven isolates comprising five species (S. hyicus, S. aureus, S. schleiferi subsp. coagulans, S. intermedius and S. lentus were characterized for their antibiotic resistance phenotypic profile and antibiotic resistance genes (mecA, cfr, gyrA, gyrB and grlA. Out of the 27 Staphylococcus isolates only one isolate was resistant to the 12 antibiotics representing nine classes. Raw beef meat sold across the Great Cairo zone, contains 66.7% of MRS, with highest prevalence was reported in S. aureus (66.7%, while the MRS non-S. aureus strains constituted 66.7% from which S. hyicus (60%, S. intermedius (33.3%, S. schleiferi subsp. coagulans (100% and S. lentus (100% were MRS. Seven S. aureus, six S. hyicus, four S. schleiferi subsp. coagulans, three S. intermedius and one S. lentus isolates although being resistant to oxacillin yet, 11/27 (40.7% carried the mecA gene. At the same time, the cfr gene was present in 2 of the nine S. aureus isolates, and totally undetectable in S. hyicus, S. schleiferi subsp. coagulans, S. intermedius and S. lentus. Although global researches largely focused into MRSA and MR-NSA in animals on pigs, the analysis of our results stipulates that buffaloes and cattle could be MRSA dispersers and that this theme is not specific to pigs. Detection of MSSA virulence determinants is a must, as although oxacillin resistance may be absent yet, the MSSA may carry the virulence determinants which could

  19. Antimicrobial Resistance, Biofilm Formation and mecA Characterization of Methicillin-Susceptible S. aureus and Non-S. aureus of Beef Meat Origin in Egypt.

    Science.gov (United States)

    Osman, Kamelia M; Amer, Aziza M; Badr, Jihan M; Helmy, Nashwa M; Elhelw, Rehab A; Orabi, Ahmed; Bakry, Magdy; Saad, Aalaa S A

    2016-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) have been found in various farm animal species throughout the world. Yet, methicillin-susceptible S. aureus (MSSA), methicillin-susceptible non-S. aureus (MS-NSA), and methicillin-resistant non-S. aureus (MR-NSA) were not investigated. Therefore, we persued to determine the diversity in their phenotypic virulence assay, phenotypic antimicrobial resistance profile and molecular characterization in one of the food chains in Egypt. Samples were collected during 2013 from beef meat at retail. Twenty seven isolates comprising five species (S. hyicus, S. aureus, S. schleiferi subsp. coagulans, S. intermedius, and S. lentus) were characterized for their antibiotic resistance phenotypic profile and antibiotic resistance genes (mecA, cfr, gyrA, gyrB, and grlA). Out of the 27 Staphylococcus isolates only one isolate was resistant to the 12 antibiotics representing nine classes. Raw beef meat sold across the Great Cairo zone, contains 66.7% of MRS, with highest prevalence was reported in S. aureus (66.7%), while the MRS non-S. aureus strains constituted 66.7% from which S. hyicus (60%), S. intermedius (33.3%), S. schleiferi subsp. coagulans (100%), and S. lentus (100%) were MRS. Seven S. aureus, six S. hyicus, four S. schleiferi subsp. coagulans, three S. intermedius, and one S. lentus isolates although being resistant to oxacillin yet, 11/27 (40.7%) carried the mecA gene. At the same time, the cfr gene was present in 2 of the nine S. aureus isolates, and totally undetectable in S. hyicus, S. schleiferi subsp. coagulans, S. intermedius, and S. lentus. Although, global researches largely focused into MRSA and MR-NSA in animals on pigs, the analysis of our results stipulates, that buffaloes and cattle could be MRSA dispersers and that this theme is not specific to pigs. Detection of MSSA virulence determinants is a must, as although oxacillin resistance may be absent yet, the MSSA may carry the virulence determinants which

  20. D-amino acids enhance the activity of antimicrobials against biofilms of clinical wound isolates of Staphylococcus aureus and Pseudomonas aeruginosa.

    Science.gov (United States)

    Sanchez, Carlos J; Akers, Kevin S; Romano, Desiree R; Woodbury, Ronald L; Hardy, Sharanda K; Murray, Clinton K; Wenke, Joseph C

    2014-08-01

    Within wounds, microorganisms predominantly exist as biofilms. Biofilms are associated with chronic infections and represent a tremendous clinical challenge. As antibiotics are often ineffective against biofilms, use of dispersal agents as adjunctive, topical therapies for the treatment of wound infections involving biofilms has gained interest. We evaluated in vitro the dispersive activity of D-amino acids (D-AAs) on biofilms from clinical wound isolates of Staphylococcus aureus and Pseudomonas aeruginosa; moreover, we determined whether combinations of D-AAs and antibiotics (clindamycin, cefazolin, oxacillin, rifampin, and vancomycin for S. aureus and amikacin, colistin, ciprofloxacin, imipenem, and ceftazidime for P. aeruginosa) enhance activity against biofilms. D-Met, D-Phe, and D-Trp at concentrations of ≥ 5 mM effectively dispersed preformed biofilms of S. aureus and P. aeruginosa clinical isolates, an effect that was enhanced when they were combined as an equimolar mixture (D-Met/D-Phe/D-Trp). When combined with D-AAs, the activity of rifampin was significantly enhanced against biofilms of clinical isolates of S. aureus, as indicated by a reduction in the minimum biofilm inhibitory concentration (MBIC) (from 32 to 8 μg/ml) and a >2-log reduction of viable biofilm bacteria compared to treatment with antibiotic alone. The addition of D-AAs was also observed to enhance the activity of colistin and ciprofloxacin against biofilms of P. aeruginosa, reducing the observed MBIC and the number of viable bacteria by >2 logs and 1 log at 64 and 32 μg/ml in contrast to antibiotics alone. These findings indicate that the biofilm dispersal activity of D-AAs may represent an effective strategy, in combination with antimicrobials, to release bacteria from biofilms, subsequently enhancing antimicrobial activity.

  1. Antimicrobial Resistance of Escherichia coli, Enterococci, Pseudomonas aeruginosa, and Staphylococcus aureus from Raw Fish and Seafood Imported into Switzerland.

    Science.gov (United States)

    Boss, Renate; Overesch, Gudrun; Baumgartner, Andreas

    2016-07-01

    A total of 44 samples of salmon, pangasius (shark catfish), shrimps, and oysters were tested for the presence of Escherichia coli, enterococci, Pseudomonas aeruginosa, and Staphylococcus aureus, which are indicator organisms commonly used in programs to monitor antibiotic resistance. The isolated bacterial strains, confirmed by matrix-assisted laser desorption ionization time-of-flight mass spectroscopy, were tested against a panel of 29 antimicrobial agents to obtain MICs. Across the four sample types, Enterococcus faecalis (59%) was most common, followed by E. coli (55%), P. aeruginosa (27%), and S. aureus (9%). All bacterial species were resistant to some antibiotics. The highest rates of resistance were in E. faecalis to tetracycline (16%), in E. coli to ciprofloxacin (22%), and in S. aureus to penicillin (56%). Antibiotic resistance was found among all sample types, but salmon and oysters were less burdened than were shrimps and pangasius. Multidrug-resistant (MDR) strains were exclusively found in shrimps and pangasius: 17% of pangasius samples (MDR E. coli and S. aureus) and 64% of shrimps (MDR E. coli, E. faecalis, and S. aureus). Two of these MDR E. coli isolates from shrimps (one from an organic sample) were resistant to seven antimicrobial agents. Based on these findings, E. coli in pangasius, shrimps, and oysters, E. faecalis in pangasius, shrimps, and salmon, and P. aeruginosa in pangasius and shrimps are potential candidates for programs monitoring antimicrobial resistance. Enrichment methods for the detection of MDR bacteria of special public health concern, such as methicillin-resistant S. aureus and E. coli producing extended-spectrum β-lactamases and carbapenemases, should be implemented.

  2. Molecular epidemiology and antimicrobial resistance of methicillin-resistant Staphylococcus aureus bloodstream isolates in Taiwan, 2010.

    Directory of Open Access Journals (Sweden)

    Chih-Jung Chen

    Full Text Available The information of molecular characteristics and antimicrobial susceptibility pattern of methicillin-resistant Staphylococcus aureus (MRSA is essential for control and treatment of diseases caused by this medically important pathogen. A total of 577 clinical MRSA bloodstream isolates from six major hospitals in Taiwan were determined for molecular types, carriage of Panton-Valentine leukocidin (PVL and sasX genes and susceptibilities to 9 non-beta-lactam antimicrobial agents. A total of 17 genotypes were identified in 577 strains by pulsotyping. Five major pulsotypes, which included type A (26.2%, belonging to sequence type (ST 239, carrying type III staphylococcal chromosomal cassette mec (SCCmec, type F (18.9%, ST5-SCCmecII, type C (18.5%, ST59-SCCmecIV, type B (12.0%, ST239-SCCmecIII and type D (10.9%, ST59-SCCmecVT/IV, prevailed in each of the six sampled hospitals. PVL and sasX genes were respectively carried by ST59-type D strains and ST239 strains with high frequencies (93.7% and 99.1%, respectively but rarely detected in strains of other genotypes. Isolates of different genotypes and from different hospitals exhibited distinct antibiograms. Multi-resistance to ≥3 non-beta-lactams was more common in ST239 isolates (100% than in ST5 isolates (97.2%, P = 0.0347 and ST59 isolates (8.2%, P<0.0001. Multivariate analysis further indicated that the genotype, but not the hospital, was an independent factor associated with muti-resistance of the MRSA strains. In conclusion, five common MRSA clones with distinct antibiograms prevailed in the major hospitals in Taiwan in 2010. The antimicrobial susceptibility pattern of invasive MRSA was mainly determined by the clonal distribution.

  3. A new class of nifuroxazide analogues: synthesis of 5-nitrothiophene derivatives with antimicrobial activity against multidrug-resistant Staphylococcus aureus.

    Science.gov (United States)

    Masunari, Andrea; Tavares, Leoberto Costa

    2007-06-15

    Hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) has been an increasing problem worldwide since the initial reports over 40 years ago. To examine new drug leads with potential antibacterial activities, 14 p-substituted benzoic acid [(5-nitro-thiophen-2-yl)-methylene]-hydrazides were designed, synthesized, and tested against standard and multidrug-resistant S. aureus strains by serial dilution tests. All compounds exhibited significant bacteriostatic activity and some of them also showed bactericidal activity. The results confirmed the potential of this class of compounds as an alternative for the development of selective antimicrobial agents.

  4. In vitro activity of ceftobiprole, linezolid, tigecycline, and 23 other antimicrobial agents against Staphylococcus aureus isolates in China.

    Science.gov (United States)

    Wang, Hui; Liu, Yudong; Sun, Hongli; Xu, Yingchun; Xie, Xiuli; Chen, Minjun

    2008-10-01

    We investigated the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in China and determined the susceptibility of S. aureus to 26 antimicrobial agents, including ceftobiprole, linezolid, and tigecycline. A total of 798 isolates were collected and tested by agar dilution. The mean prevalence of MRSA was 50.4%, the highest in Shanghai (80.3%), followed by those in Beijing (55.5%) and Shenyang (50.0%). Only 4.2% to 12.6% of MRSA were susceptible to erythromycin, fluoroquinolones, gentamicin, and tetracycline. All isolates were susceptible to teicoplanin, vancomycin, linezolid, tigecycline, and ceftobiprole.

  5. Commensal Protection of Staphylococcus aureus against Antimicrobials by Candida albicans Biofilm Matrix

    Science.gov (United States)

    Kong, Eric F.; Tsui, Christina; Kucharíková, Sona; Andes, David

    2016-01-01

    ABSTRACT Biofilm-associated polymicrobial infections, particularly those involving fungi and bacteria, are responsible for significant morbidity and mortality and tend to be challenging to treat. Candida albicans and Staphylococcus aureus specifically are considered leading opportunistic fungal and bacterial pathogens, respectively, mainly due to their ability to form biofilms on catheters and indwelling medical devices. However, the impact of mixed-species biofilm growth on therapy remains largely understudied. In this study, we investigated the influence of C. albicans secreted cell wall polysaccharides on the response of S. aureus to antibacterial agents in biofilm. Results demonstrated significantly enhanced tolerance for S. aureus to drugs in the presence of C. albicans or its secreted cell wall polysaccharide material. Fluorescence confocal time-lapse microscopy revealed impairment of drug diffusion through the mixed biofilm matrix. Using C. albicans mutant strains with modulated cell wall polysaccharide expression, exogenous supplementation, and enzymatic degradation, the C. albicans-secreted β-1,3-glucan cell wall component was identified as the key matrix constituent providing the bacteria with enhanced drug tolerance. Further, antibody labeling demonstrated rapid coating of the bacteria by the C. albicans matrix material. Importantly, via its effect on the fungal biofilm matrix, the antifungal caspofungin sensitized the bacteria to the drugs. Understanding such symbiotic interactions with clinical relevance between microbial species in biofilms will greatly aid in overcoming the limitations of current therapies and in defining potential new targets for treating polymicrobial infections. PMID:27729510

  6. Commensal Protection of Staphylococcus aureus against Antimicrobials by Candida albicans Biofilm Matrix

    Directory of Open Access Journals (Sweden)

    Eric F. Kong

    2016-10-01

    Full Text Available Biofilm-associated polymicrobial infections, particularly those involving fungi and bacteria, are responsible for significant morbidity and mortality and tend to be challenging to treat. Candida albicans and Staphylococcus aureus specifically are considered leading opportunistic fungal and bacterial pathogens, respectively, mainly due to their ability to form biofilms on catheters and indwelling medical devices. However, the impact of mixed-species biofilm growth on therapy remains largely understudied. In this study, we investigated the influence of C. albicans secreted cell wall polysaccharides on the response of S. aureus to antibacterial agents in biofilm. Results demonstrated significantly enhanced tolerance for S. aureus to drugs in the presence of C. albicans or its secreted cell wall polysaccharide material. Fluorescence confocal time-lapse microscopy revealed impairment of drug diffusion through the mixed biofilm matrix. Using C. albicans mutant strains with modulated cell wall polysaccharide expression, exogenous supplementation, and enzymatic degradation, the C. albicans-secreted β-1,3-glucan cell wall component was identified as the key matrix constituent providing the bacteria with enhanced drug tolerance. Further, antibody labeling demonstrated rapid coating of the bacteria by the C. albicans matrix material. Importantly, via its effect on the fungal biofilm matrix, the antifungal caspofungin sensitized the bacteria to the drugs. Understanding such symbiotic interactions with clinical relevance between microbial species in biofilms will greatly aid in overcoming the limitations of current therapies and in defining potential new targets for treating polymicrobial infections.

  7. Antibiotic Exposure and Other Risk Factors for Antimicrobial Resistance in Nasal Commensal Staphylococcus aureus: An Ecological Study in 8 European Countries

    NARCIS (Netherlands)

    Bijnen, E.M. van; Paget, J.; Lange-de Klerk, E.S. de; Heijer, C.D. den; Versporten, A.; Stobberingh, E.E.; Goossens, H.; Schellevis, F.G.

    2015-01-01

    OBJECTIVES: Antimicrobial resistance (AMR) has become a global public health concern which threatens the effective treatment of bacterial infections. Resistant Staphylococcus aureus (including MRSA) increasingly appears in individuals with no healthcare associated risks. Our study assessed risk fact

  8. Antibiotic exposure and other risk factors for antimicrobial resistance in nasal commensal staphylococcus aureus: an ecological study in 8 European countries.

    NARCIS (Netherlands)

    Bijnen, E.M.E. van; Paget, W.J.; Lange-de Klerk, E.S.M. de; Heijer, C.D.J. den; Versporten, A.; Stobberingh, E.E.; Goossen, H.; Schellevis, F.G.

    2015-01-01

    Objectives: Antimicrobial resistance (AMR) has become a global public health concern which threatens the effective treatment of bacterial infections. Resistant Staphylococcus aureus (including MRSA) increasingly appears in individuals with no healthcare associated risks. Our study assessed risk fact

  9. Clinical Impact of Antimicrobial Resistance in European Hospitals : Excess Mortality and Length of Hospital Stay Related to Methicillin-Resistant Staphylococcus aureus Bloodstream Infections

    NARCIS (Netherlands)

    de Kraker, Marlieke E. A.; Wolkewitz, Martin; Davey, Peter G.; Grundmann, Hajo

    2011-01-01

    Antimicrobial resistance is threatening the successful management of nosocomial infections worldwide. Despite the therapeutic limitations imposed by methicillin-resistant Staphylococcus aureus (MRSA), its clinical impact is still debated. The objective of this study was to estimate the excess mortal

  10. Antibiotic-specific differences in the response of Staphylococcus aureus to treatment with antimicrobials combined with manuka honey

    Directory of Open Access Journals (Sweden)

    Michael eLiu

    2015-01-01

    Full Text Available Skin infections caused by antibiotic resistant Staphylococcus aureus are a significant health problem worldwide; often associated with high treatment cost and mortality rate. Complex natural products like New Zealand (NZ manuka honey have been revisited and studied extensively as an alternative to antibiotics due to their potent broad-spectrum antimicrobial activity, and the inability to isolate honey-resistant S. aureus. Previous studies showing synergistic effects between manuka-type honeys and antibiotics have been demonstrated against the growth of one methicillin-resistant S. aureus (MRSA strain. We have previously demonstrated strong synergistic activity between NZ manuka-type honey and rifampicin against growth and biofilm formation of multiple S. arueus strains. Here, we have expanded our investigation using multiple S. aureus strains and four different antibiotics commonly used to treat S. aureus-related skin infections: rifampicin, oxacillin, gentamicin and clindamycin. Using checkerboard microdilution and agar diffusion assays with S. aureus strains including clinical isolates and MRSA we demonstrate that manuka-type honey combined with these four antibiotics frequently produces a synergistic effect. In some cases when synergism was not observed, there was a significant enhancement in antibiotic susceptibility. Some strains that were highly resistant to an antibiotic when present alone become sensitive to clinically-achievable concentrations when combined with honey. However, not all of the S. aureus strains tested responded in the same way to these combinational treatments. Our findings support the use of NZ manuka-type honeys in clinical treatment against S. aureus-related infections and extend their potential use as an antibiotic adjuvant in combinational therapy. Our data also suggest that manuka-type honeys may not work as antibiotic adjuvants for all strains of S. aureus, and this may help determine the mechanistic processes

  11. Relative efficacy of cefuroxime versus dicloxacillin as definitive antimicrobial therapy in methicillin-susceptible Staphylococcus aureus bacteraemia

    DEFF Research Database (Denmark)

    Rasmussen, Jon Bjarke; Knudsen, Jenny Dahl; Arpi, Magnus;

    2014-01-01

    OBJECTIVES: The objective of the present study was to compare the efficacy of cefuroxime with that of dicloxacillin as definitive antimicrobial therapy in methicillin-susceptible Staphylococcus aureus bacteraemia (MS-SAB) using a Danish bacteraemia database, information on the indication for anti......OBJECTIVES: The objective of the present study was to compare the efficacy of cefuroxime with that of dicloxacillin as definitive antimicrobial therapy in methicillin-susceptible Staphylococcus aureus bacteraemia (MS-SAB) using a Danish bacteraemia database, information on the indication...... for antimicrobial therapy, multivariate adjustment and propensity score (PS) matching. METHODS: This was a retrospective cohort study. MS-SAB cases from 1 January 2006 to 31 December 2008 were included from a total of seven hospitals in the greater Copenhagen area and seven hospitals in the North Denmark Region....... Information including demographics, antimicrobial therapy and clinical condition was obtained. The physician's note detailing the indication for starting empirical antimicrobial therapy was given special attention. Hazard ratios (HRs) and 95% CIs for 30 day and 90 day mortality were calculated using PS...

  12. Social stress and resistance of chicken and swine to Staphylococcus aureus challenge infections.

    OpenAIRE

    Larson, C T; Gross, W B; Davis, J W

    1985-01-01

    The purpose of this research was to determine the effect of social stress on the susceptibility of chickens and swine to Staphylococcus aureus infection. Chickens were housed under four levels of social stress. Weaned pigs remained with their litter or were housed separately. One day after some birds were placed in the high stressed environments all were challenged intravenously with S. aureus. Susceptibility was characterized by joint infection in swine and reduced weight gain in chickens. C...

  13. Primary care treatment guidelines for skin infections in Europe: congruence with antimicrobial resistance found in commensal Staphylococcus aureus in the community

    NARCIS (Netherlands)

    Bijnen, E.M. van; Paget, W.J.; Heijer, C. den; Stobberingh, E.E.; Bruggeman, C.A.; Schellevis, F.G.; team, A.s.

    2014-01-01

    BACKGROUND: Over 90% of antibiotics for human use in Europe are prescribed in primary care. We assessed the congruence between primary care treatment guidelines for skin infections and commensal Staphylococcus aureus (S. aureus) antimicrobial resistance levels in community-dwelling persons. METHODS:

  14. Primary care treatment guidelines for skin infections in Europe: congruence with antimicrobial resistance found in commensal Staphylococcus aureus in the community.

    NARCIS (Netherlands)

    Bijnen, E.M.E. van; Paget, W.J.; Heijer, C.D.J. den; Stobberingh, E.E.; Bruggeman, C.A.; Schellevis, F.G.

    2014-01-01

    Background: Over 90% of antibiotics for human use in Europe are prescribed in primary care. We assessed the congruence between primary care treatment guidelines for skin infections and commensal Staphylococcus aureus (S. aureus) antimicrobial resistance levels in community-dwelling persons. Methods:

  15. Antimicrobial Analysis of an Antiseptic Made from Ethanol Crude Extracts of P. granatum and E. uniflora in Wistar Rats against Staphylococcus aureus and Staphylococcus epidermidis

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    Thaís Honório Lins Bernardo

    2015-01-01

    Full Text Available Introduction. Surgical site infection remains a challenge for hospital infection control, especially when it relates to skin antisepsis in the surgical site. Objective. To analyze the antimicrobial activity in vivo of an antiseptic from ethanol crude extracts of P. granatum and E. uniflora against Gram-positive and Gram-negative bacteria. Methods. Agar drilling and minimal inhibitory tests were conducted for in vitro evaluation. In the in vivo bioassay were used Wistar rats and Staphylococcus aureus (ATCC 25923 and Staphylococcus epidermidis (ATCC 14990. Statistical analysis was performed through variance analysis and Scott-Knott cluster test at 5% probability and significance level. Results. In the in vitro, ethanolic extracts of Punica granatum and Eugenia uniflora and their combination showed the best antimicrobial potential against S. epidermidis and S. aureus. In the in vivo bioassay against S. epidermidis, there was no statistically significant difference between the tested product and the patterns used after five minutes of applying the product. Conclusion. The results indicate that the originated product is an antiseptic alternative source against S. epidermidis compared to chlorhexidine gluconate. It is suggested that further researches are to be conducted in different concentrations of the test product, evaluating its effectiveness and operational costs.

  16. Zinc ascorbate has superoxide dismutase-like activity and in vitro antimicrobial activity against Staphylococcus aureus and Escherichia coli

    OpenAIRE

    2012-01-01

    Katsuhiro Iinuma, Isami TsuboiBML General Laboratory, Kawagoe, Saitama, JapanBackground: Acne vulgaris is a common dermatological disease, and its pathogenesis is multifactorial.Objective: We examined whether the ascorbic acid derivative zinc ascorbate has superoxide dismutase (SOD)-like activity. SOD is an enzyme that controls reactive oxygen species production. In addition, the in vitro antimicrobial activity of zinc ascorbate against the Gram-positive bacterium Staphylococcus aureus and th...

  17. Antimicrobial susceptibility profiles of Staphylococcus aureus isolates classified according to their origin in a tertiary hospital in Korea.

    Science.gov (United States)

    Moon, Hee-Won; Kim, Hyun Jung; Hur, Mina; Yun, Yeo-Min

    2014-12-01

    We performed a comprehensive analysis on 3,594 Staphylococcus aureus isolates from routine culture during the last 4 years. The antimicrobial susceptibilities of the isolates were analyzed according to their origin and were compared based on the type of specimens. The proportion of methicillin-resistant Staphylococcus aureus (MRSA) in community-associated (CA), health care-associated, community onset (HACO), and health care-associated (HA) isolates were 33.0%, 54.3%, and 73.3%, respectively. The MRSA rate differed significantly between specimens, with the highest rate from urine in the CA and HACO isolates, whereas the highest rate from the respiratory tract was in the HA isolates. The monitoring of the MRSA rate in CA, HACO, and HA S aureus isolates would be valuable for surveillance. The elevated rates of MRSA in urinary specimens from CA and HCA isolates need to be addressed for infection control.

  18. Antimicrobial efficacy of silver ions in combination with tea tree oil against Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans.

    Science.gov (United States)

    Low, W L; Martin, C; Hill, D J; Kenward, M A

    2011-02-01

    Tea tree oil (TTO) and silver ions (Ag(+)), either alone or in combination with other antimicrobial compounds, have been used in the treatment of topical infections. However, there appears to be little data on the efficacy of TTO combined with silver in the absence of any other agents. TTO and Ag(+) were added, alone and in combination, to suspension cultures of Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans. Treatment of these cultures with TTO and Ag(+) at sub-minimal lethal concentrations resulted in an enhanced loss of viability compared with treatment with individual agents. The order of sensitivity to the combined agents was P. aeruginosa>S. aureus>C. albicans. The fractional lethal concentration index (FLCI) showed that these combinations of TTO and Ag(+) exerted a synergistic effect against P. aeruginosa (FLCI=0.263) and an indifferent effect against S. aureus and C. albicans (FLCI=0.663 and 1.197, respectively). The results indicate that combining these antimicrobial agents may be useful in decreasing the concentration of antimicrobial agents required to achieve an effective reduction in opportunistic pathogenic microorganisms that typically infect wounds.

  19. The antimicrobial effect of Octenidine-dihydrochloride coated polymer tracheotomy tubes on Staphylococcus aureus and Pseudomonas aeruginosa colonisation

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    Leonhard Matthias

    2009-07-01

    Full Text Available Abstract Background The surface of polymeric tracheotomy tubes is a favourable environment for biofilm formation and therefore represents a potential risk factor for the development of pneumonia after tracheotomy. The aim of this in-vitro study was to develop octenidine-dihydrochloride (OCT coated polymer tracheotomy tubes and investigate any effects on Staphylococcus (S. aureus and Pseudomonas (P. aeruginosa colonization. Additionally the resistance of the OCT coating was tested using reprocessing procedures like brushing, rinsing and disinfection with glutaraldehyde Results Contamination with S. aureus: Before any reprocessing, OCT coated tracheotomy tubes were colonized with 103 cfu/ml and uncoated tracheotomy tubes with 105 cfu/ml (P = 0.045. After reprocessing, no differences in bacterial concentration between modified and conventional tubes were observed. Contamination with P. aeruginosa: Before reprocessing, OCT coated tubes were colonized with 106 cfu/ml and uncoated tubes with 107 cfu/ml (P = 0.006. After reprocessing, no significant differences were observed. Conclusion OCT coating initially inhibits S. aureus and P. aeruginosa colonisation on tracheotomy tubes. This effect, however, vanishes quickly after reprocessing of the tubes due to poor adhesive properties of the antimicrobial compound. Despite the known antimicrobial effect of OCT, its use for antimicrobial coating of tracheotomy tubes is limited unless methods are developed to allow sustained attachment to the tube.

  20. Anti-Inflammatory and Antimicrobial Effects of Estradiol in Bovine Mammary Epithelial Cells during Staphylococcus aureus Internalization

    Science.gov (United States)

    Medina-Estrada, Ivan; López-Meza, Joel E.

    2016-01-01

    17β-Estradiol (E2), the predominant sexual hormone in females, is associated with the modulation of the innate immune response (IIR), and changes in its levels at parturition are related to intramammary infections, such as mastitis. In bovine mammary epithelial cells (bMECs), E2 regulates differentiation and proliferation, but its immunomodulatory functions have not been explored. Staphylococcus aureus is the predominant pathogen causing mastitis, which can persist intracellularly in bMECs. The aim of this work was to analyze whether E2 modulates the IIR of bMECs during S. aureus internalization. bMECs treated with E2 (50 pg/mL, 24 h) reduced bacteria internalization (~50%). The host receptors α5β1 and TLR2 do not participate in this reduction. However, E2 activates ERα and modulates the IIR reducing the S. aureus induced-mRNA expression of TNF-α (~50%) and IL-1β (90%). E2 also decreased the secretion of these cytokines as well as IL-6 production; however, in infected bMECs, E2 induced the secretion of IL-1β. Furthermore, E2 upregulates the expression of the antimicrobial peptides DEFB1, BNBD5, and psoriasin S100A7 (~5-, 3-, and 6-fold, resp.). In addition, E2 induced the production of antimicrobial compounds in bMEC culture medium, which, together with the modulation of the IIR, could be related to the reduction of S. aureus internalization. PMID:27034592

  1. Staphylococcus aureus and wounds: a review of tea tree oil as a promising antimicrobial.

    Science.gov (United States)

    Halcón, Linda; Milkus, Kelly

    2004-11-01

    Antibiotic-resistant bacteria continue to be a major health concern worldwide. In particular, Staphylococcus aureus, both methicillin-resistant and -sensitive, are of concern in their ability to cause difficult skin and underlying tissue infections. Melaleuca alternifolia oil (tea tree oil), an essential oil, has demonstrated promising efficacy in treating these infections. Tea tree oil has been used for centuries as a botanical medicine, and has only in recent decades surfaced in the scientific literature as a promising adjunctive wound treatment. Tea tree oil is antimicrobial, anti-inflammatory, and has demonstrated ability to activate monocytes. There are few apparent side effects to using tea tree oil topically in low concentrations, with contact dermatitis being the most common. Tea tree oil has been effective as an adjunctive therapy in treating osteomyelitis and infected chronic wounds in case studies and small clinical trials. There is a need for larger clinical trials to further examine efficacy of tea tree oil as an adjunctive wound therapy, as well as improved guidelines for developing plant-based medicines.

  2. In-vitro antimicrobial activity of marine actinobacteria against multidrug resistance Staphylococcus aureus

    Institute of Scientific and Technical Information of China (English)

    Sathish; Kumar; SR; Kokati; Venkata; Bhaskara; Rao

    2012-01-01

    Objective:To investigate the antibacterial aclivily of marine actinobacteria against multidrug resistance Staphylococcus aureus(MDRSA).Methods:Fifty one actinobacterial strains were isolated from salt pans soil,costal area in Kothapattanam,Ongole,Andhra Pradesh.Primary screening was done using cross-streak method against MDRSA.The bioaclive compounds are extracted from efficient actinobacteria using solvent extraction.The antimicrobial activity of crude and solvent extracts was perfomied using Kirby-Bauer method.MIC for ethyl acetate extract was determined by modified agar well diffusion method.The potent actinobacteria are identified using Nonomura key,Shirling and Gottlieb 1966 with Bergey’s manual of determinative bacteriology.Results:Among the fifty one isolates screened for antibacterial activity,SRB25were found efficient against MDRSA.The ethyl acetate extracts showed high inhibition against test organism.MIC test was performed with the ethyl acetate extract against MDRSA and found to be 1 000μg/mL.The isolaled actinobacteria are identified as Streptomyces sp with the help of Nonomura key.Conclusions:The current investigation reveals that the marine actinobacteria from salt pan environment can be able to produce new drug molecules against drug resistant microorganisms.

  3. In-vitro antimicrobial activity of marine actinobacteria against multidrug resistance Staphylococcus aureus

    Institute of Scientific and Technical Information of China (English)

    Sathish Kumar S.R; Kokati Venkata Bhaskara Rao

    2012-01-01

    Objective: To investigate the antibacterial activity of marine actinobacteria against Multidrug resistance Staphylococcus aureus (MDRSA). Methods: Fifty one actinobacterial strains were isolated from salt pans soil, costal area in Kothapattanam, Ongole, Andhra Pradesh. Primary screening was done using cross-streak method against MDRSA. The bioactive compounds are extracted from efficient actinobacteria using solvent extraction. The antimicrobial activity of crude and solvent extracts was performed using Kirby-Bauer method. MIC for ethyl acetate extract was determined by modified agar well diffusion method. The potent actinobacteria are identified using Nonomura key, Shirling and Gottlieb 1966 with Bergey’s manual of Determinative Bacteriology. Results: Among the fifty one isolates screened for antibacterial activity, SRB25 were found efficient against MDRSA. The ethyl acetate extracts showed high inhibition against test organism. MIC test was performed with the ethyl acetate extract against MDRSA and found to be 1000μg/ml. The isolated actinobacteria are identified as Streptomyces sp with the help of Nonomura key. Conclusion: The current investigation reveals that the marine actinobacteria from salt pan environment can be able to produce new drug molecules against drug resistant microorganisms.

  4. In-vitro antimicrobial activity of marine actinobacteria against multidrug resistance Staphylococcus aureus

    Institute of Scientific and Technical Information of China (English)

    Sathish Kumar SR; Kokati Venkata Bhaskara Rao

    2012-01-01

    To investigate the antibacterial activity of marine actinobacteria against multidrug resistance Staphylococcus aureus (MDRSA). Methods: Fifty one actinobacterial strains were isolated from salt pans soil, costal area in Kothapattanam, Ongole, Andhra Pradesh. Primary screening was done using cross-streak method against MDRSA. The bioactive compounds are extracted from efficient actinobacteria using solvent extraction. The antimicrobial activity of crude and solvent extracts was performed using Kirby-Bauer method. MIC for ethyl acetate extract was determined by modified agar well diffusion method. The potent actinobacteria are identified using Nonomura key, Shirling and Gottlieb 1966 with Bergey's manual of determinative bacteriology. Results: Among the fifty one isolates screened for antibacterial activity, SRB25 were found efficient against MDRSA. The ethyl acetate extracts showed high inhibition against test organism. MIC test was performed with the ethyl acetate extract against MDRSA and found to be 1 000 μg/mL. The isolated actinobacteria are identified as Streptomyces sp with the help of Nonomura key. Conclusions: The current investigation reveals that the marine actinobacteria from salt pan environment can be able to produce new drug molecules against drug resistant microorganisms.

  5. Injections through skin colonized with Staphylococcus aureus biofilm introduce contamination despite standard antimicrobial preparation procedures

    Science.gov (United States)

    Wang, Yi; Leng, Valery; Patel, Viraj; Phillips, K. Scott

    2017-01-01

    While surgical site preparation has been extensively studied, there is little information about resistance of skin microbiota in the biofilm form to antimicrobial decontamination, and there are no quantitative models to study how biofilm might be transferred into sterile tissue/implant materials during injections for joint spine and tendon, aspiration biopsies and dermal fillers (DF). In this work, we develop two in vitro models to simulate the process of skin preparation and DF injection using pig skin and SimSkin (silicone) materials, respectively. Using the pig skin model, we tested three of the most common skin preparation wipes (alcohol, chlorhexidine and povidone iodine) and found that during wiping they reduced the biofilm bacterial burden of S. aureus (CFU cm−2) by three logs with no statistically significant differences between wipes. Using the SimSkin model, we found that transfer of viable bacteria increased with needle diameter for 30G, 25G and 18G needles. Transfer incidence decreased as injection depth was increased from 1 mm to 3 mm. Serial puncture and linear threading injection styles had similar transfer incidence, whereas fanning significantly increased transfer incidence. The results show that contamination of DF during injection is a risk that can be reduced by modifying skin prep and injection practices. PMID:28332593

  6. Antimicrobial peptide exposure selects for Staphylococcus aureus resistance to human defence peptides

    Science.gov (United States)

    Kubicek-Sutherland, Jessica Z.; Lofton, Hava; Vestergaard, Martin; Hjort, Karin; Ingmer, Hanne; Andersson, Dan I.

    2017-01-01

    Background The clinical development of antimicrobial peptides (AMPs) is currently under evaluation to combat the rapid increase in MDR bacterial pathogens. However, many AMPs closely resemble components of the human innate immune system and the ramifications of prolonged bacterial exposure to AMPs are not fully understood. Objectives We show that in vitro serial passage of a clinical USA300 MRSA strain in a host-mimicking environment containing host-derived AMPs results in the selection of stable AMP resistance. Methods Serial passage experiments were conducted using steadily increasing concentrations of LL-37, PR-39 or wheat germ histones. WGS and proteomic analysis by MS were used to identify the molecular mechanism associated with increased tolerance of AMPs. AMP-resistant mutants were characterized by measuring in vitro fitness, AMP and antibiotic susceptibility, and virulence in a mouse model of sepsis. Results AMP-resistant Staphylococcus aureus mutants often displayed little to no fitness cost and caused invasive disease in mice. Further, this phenotype coincided with diminished susceptibility to both clinically prescribed antibiotics and human defence peptides. Conclusions These findings suggest that therapeutic use of AMPs could select for virulent mutants with cross-resistance to human innate immunity as well as antibiotic therapy. Thus, therapeutic use of AMPs and the implications of cross-resistance need to be carefully monitored and evaluated. PMID:27650186

  7. Altered Competitive Fitness, Antimicrobial Susceptibility, and Cellular Morphology in a Triclosan-Induced Small-Colony Variant of Staphylococcus aureus.

    Science.gov (United States)

    Forbes, Sarah; Latimer, Joe; Bazaid, Abdulrahman; McBain, Andrew J

    2015-08-01

    Staphylococcus aureus can produce small-colony variants (SCVs) that express various phenotypes. While their significance is unclear, SCV propagation may be influenced by relative fitness, antimicrobial susceptibility, and the underlying mechanism. We have investigated triclosan-induced generation of SCVs in six S. aureus strains, including methicillin-resistant S. aureus (MRSA). Parent strains (P0) were repeatedly passaged on concentration gradients of triclosan using a solid-state exposure system to generate P10. P10 was subsequently passaged without triclosan to generate X10. Susceptibility to triclosan and 7 antibiotics was assessed at all stages. For S. aureus ATCC 6538, SCVs were further characterized by determining microbicide susceptibility and competitive fitness. Cellular morphology was examined using electron microscopy, and protein expression was evaluated through proteomics. Triclosan susceptibility in all SCVs (which could be generated from 4/6 strains) was markedly decreased, while antibiotic susceptibility was significantly increased in the majority of cases. An SCV of S. aureus ATCC 6538 exhibited significantly increased susceptibility to all tested microbicides. Cross-wall formation was impaired in this bacterium, while expression of FabI, a target of triclosan, and IsaA, a lytic transglycosylase involved in cell division, was increased. The P10 SCV was 49% less fit than P0. In summary, triclosan exposure of S. aureus produced SCVs in 4/6 test bacteria, with decreased triclosan susceptibility but with generally increased antibiotic susceptibility. An SCV derived from S. aureus ATCC 6538 showed reduced competitive fitness, potentially due to impaired cell division. In this SCV, increased FabI expression could account for reduced triclosan susceptibility, while IsaA may be upregulated in response to cell division defects.

  8. Prevalence, Molecular Characterization, and Antimicrobial Susceptibility of Methicillin-Resistant Staphylococcus aureus Isolated from Milk and Dairy Products.

    Science.gov (United States)

    Al-Ashmawy, Maha Abdou; Sallam, Khalid Ibrahim; Abd-Elghany, Samir Mohammed; Elhadidy, Mohamed; Tamura, Tomohiro

    2016-03-01

    The present work was undertaken to study the prevalence, molecular characterization, virulence factors, and antimicrobial susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) in raw milk and dairy products in Mansoura City, Egypt. MRSA was detected in 53% (106/200) among all milk and dairy products with prevalence rates of 75%, 65%, 40%, 50%, and 35% in raw milk, Damietta cheese, Kareish cheese, ice cream, and yogurt samples, respectively. The mean S. aureus counts were 3.49, 3.71, 2.93, 3.40, and 3.23 log10 colony-forming units (CFU)/g among tested raw milk, Damietta cheese, Kareish cheese, ice cream and yogurt, respectively, with an overall count of 3.41 log10 CFU/g. Interestingly, all recovered S. aureus isolates were genetically verified as MRSA strains by molecular detection of the mecA gene. Furthermore, genes encoding α-hemolysin (hla) and staphylococcal enterotoxins (sea, seb, sec) were detected in all isolates. The antimicrobial susceptibility pattern of recovered MRSA isolates against 13 tested antimicrobials revealed that the least effective drugs were penicillin G, cloxacillin, tetracycline, and amoxicillin with bacterial resistance percentages of 87.9%, 75.9%, 65.2%, and 55.6%, respectively. These findings suggested that milk and dairy products represent a potential infection risk threat of multidrug-resistant and toxigenic S. aureus in Egypt due to neglected hygienic practices during production, retail, or storage stages. These findings highlighted the crucial importance of applying more restrictive hygienic measures in dairy production in Egypt for food safety.

  9. Antimicrobial susceptibility patterns and characterization of clinical isolates of Staphylococcus aureus in KwaZulu-Natal province, South Africa

    Directory of Open Access Journals (Sweden)

    Lin Johnson

    2006-07-01

    Full Text Available Abstract Background Antimicrobial resistance of Staphylococcus aureus especially methicillin-resistant S. aureus (MRSA continues to be a problem for clinicians worldwide. However, few data on the antibiotic susceptibility patterns of S. aureus isolates in South Africa have been reported and the prevalence of MRSA in the KwaZulu-Natal (KZN province is unknown. In addition, information on the characterization of S. aureus in this province is unavailable. This study investigated the susceptibility pattern of 227 S. aureus isolates from the KZN province, South Africa. In addition, characterization of methicillin-sensitive S. aureus (MSSA and MRSA are reported in this survey. Methods The in-vitro activities of 20 antibiotics against 227 consecutive non-duplicate S. aureus isolates from clinical samples in KZN province, South Africa were determined by the disk-diffusion technique. Isolates resistant to oxacillin and mupirocin were confirmed by PCR detection of the mecA and mup genes respectively. PCR-RFLP of the coagulase gene was employed in the characterization of MSSA and MRSA. Results All the isolates were susceptible to vancomycin, teicoplanin and fusidic acid, and 26.9% of isolates studied were confirmed as MRSA. More than 80% of MRSA were resistant to at least four classes of antibiotics and isolates grouped in antibiotype 8 appears to be widespread in the province. The MSSA were also susceptible to streptomycin, neomycin and minocycline, while less than 1% was resistant to chloramphenicol, ciprofloxacin, rifampicin and mupirocin. The inducible MLSB phenotype was detected in 10.8% of MSSA and 82% of MRSA respectively, and one MSSA and one MRSA exhibited high-level resistance to mupirocin. There was good correlation between antibiotyping and PCR-RFLP of the coagulase gene in the characterization of MRSA in antibiotypes 1, 5 and 12. Conclusion In view of the high resistance rates of MRSA to gentamicin, erythromycin, clindamycin, rifampicin and

  10. Phenotypic and genotypic antimicrobial resistance traits of foodborne Staphylococcus aureus isolates from Shanghai

    Science.gov (United States)

    Staphylococcus aureus is a recognized pathogen in humans, which causes nosocomial infections and food poisoning. The transmission of antibiotic resistant S. aureus (ARSA), especially methicillin-resistant S. aureus (MRSA), between food products and humans has become a serious problem. Hence, it is n...

  11. Antimicrobial susceptibility of photodynamic therapy (UVA/riboflavin against Staphylococcus aureus Suscetibilidade antimicrobiana da terapia fotodinâmica (UVA/riboflavina contra Staphylococcus aureus

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    Renata Tiemi Kashiwabuchi

    2012-12-01

    Full Text Available PURPOSE: To assess S. aureus in vitro viability after the exposure to ultraviolet light A (UVA and riboflavin (B2. METHODS: Samples of S. aureus in 96 well plates (in triplicate were exposed to riboflavin (B2 and ultraviolet light A (365 nm wavelength at a power density of 3 mW/cm², 8 mm spot diameter, for 30 minutes. Control groups were prepared as well in triplicate: blank control, ultraviolet light A only, riboflavin only and dead bacteria Control. The bacterial viability was measured using fluorescent microscopy. In order to investigate the occurrence of "viable but non-culturable" microorganisms after treatment, the cell viability was also investigated by plate culture procedure onto a broth medium. Statistical analysis was performed using the triplicate values from each experimental condition. RESULTS: No difference was observed among the treatment group and the control samples (p=1. CONCLUSION: The combination of riboflavin 0.1% and ultraviolet light A at 365 nm did not exhibit antimicrobial activity against oxacillin susceptible S. aureus.OBJETIVO: Avaliar a viabilidade celular de S. aureus in vitro após a exposição de riboflavina (B2 e luz ultravioleta A (UVA. MÉTODOS: Amostras de S. aureus colocadas em uma placa de 96 poços (em triplicata foram expostas a riboflavina 0,1% (B2 e luz ultravioleta (comprimento de onda de 365 nm poder de 3 mW/cm², 8 mm de diâmetro, por 30 minutos. Grupos controles foram também preparados em triplicata: controle branco, somente luz ultravioleta A, somente riboflavina e controle morto. A viabilidade bacteriana foi analisada usando microscópio de fluorescência. Para investigar a ocorrência de micro-organismos "viáveis porem não cultiváveis" a viabilidade celular foi avaliada utilizando-se placas de meio de cultivo bacteriano. Analise estatística foi realizada utilizando-se os valores obtidos em triplicata de cada grupo experimental. RESULTADOS: Nenhuma diferença foi observada entre o grupo

  12. Ciprofloxacin HCl-loaded calcium carbonate nanoparticles: preparation, solid state characterization, and evaluation of antimicrobial effect against Staphylococcus aureus.

    Science.gov (United States)

    Maleki Dizaj, Solmaz; Lotfipour, Farzaneh; Barzegar-Jalali, Mohammad; Zarrintan, Mohammad-Hossein; Adibkia, Khosro

    2017-05-01

    Ciprofloxacin HCl-loaded calcium carbonate (CaCO3) nanoparticles were prepared via a w/o microemulsion method and characterized by dynamic light scattering, scanning electron microscopy, X-ray powder diffraction (XRPD) analysis, differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). The in vitro drug release profiles as well as antimicrobial effect against Staphylococcus aureus (S. aureus) were also evaluated. The antibacterial effect was studied using serial dilution technique to determine the minimum inhibitory concentration (MIC) of the nanoparticles and was confirmed by streak cultures. The mean particle size, drug loading and entrapment efficiency were calculated to be 116.09 nm, 20.49% and 44.05%, respectively. PXRD and FTIR studies confirmed that both vaterite and calcite polymorphs of CaCO3 were formed during the preparation process. In vitro release profiles of the nanoparticles showed slow release pattern for 12 h. The drug-loaded nanoparticles showed similar MICs against S. aureus compared to untreated drug. However, a preserved antimicrobial effect was observed for drug-loaded nanoparticles compared to untreated drug after 2 days of incubation.

  13. Low cytotoxic trace element selenium nanoparticles and their differential antimicrobial properties against S. aureus and E. coli

    Science.gov (United States)

    Tran, Phong A.; O'Brien-Simpson, Neil; Reynolds, Eric C.; Pantarat, Namfon; Biswas, Dhee P.; O'Connor, Andrea J.

    2016-01-01

    Antimicrobial agents that have no or low cytotoxicity and high specificity are desirable to have no or minimal side effects. We report here the low cytotoxicity of polyvinyl alcohol-stabilized selenium (Se) nanoparticles and their differential effects on growth of S. aureus, a gram-positive bacterium and E. coli, a gram-negative bacterium. The nanoparticles were synthesised through redox reactions in an aqueous environment at room temperature and were characterised using UV visible spectrophotometry, transmission electron microscopy, dynamic light scattering and x-ray photoelectron spectroscopy. The nanoparticles showed low toxicity toward fibroblasts which remained more than 70% viable at Se concentrations as high as 128 ppm. The nanoparticles also exhibited very low haemolysis with only 18% of maximal lysis observed at a Se concentration of 128 ppm. Importantly, the nanoparticles showed strong growth inhibition toward S. aureus at a concentration as low as 1 ppm. Interestingly, growth of E. coli was unaffected at all concentrations tested. This study therefore strongly suggests that these nanoparticles should be investigated further to understand this differential effect as well as for potential advanced antimicrobial applications such as S. aureus infection—resisting, non-cytotoxic coatings for medical devices.

  14. Comparison of the In vitro Activity of Five Antimicrobial Drugs against Staphylococcus pseudintermedius and Staphylococcus aureus Biofilms

    Science.gov (United States)

    Ferran, Aude A.; Liu, JingJing; Toutain, Pierre-Louis; Bousquet-Mélou, Alain

    2016-01-01

    Resistance in canine pathogenic staphylococci is necessitating re-evaluation of the current antimicrobial treatments especially for biofilm-associated infections. Long, repeated treatments are often required to control such infections due to the tolerance of bacteria within the biofilm. To comply with the goal of better antibiotic stewardship in veterinary medicine, the efficacies of the available drugs need to be directly assessed on bacterial biofilms. We compared the activities of amoxicillin, cefalexin, clindamycin, doxycycline, and marbofloxacin on in vitro biofilms of Staphylococcus pseudintermedius and Staphylococcus aureus. Exposure of biofilms for 15 h to maximum concentrations of the antibiotics achievable in canine plasma only reduced biofilm bacteria by 0.5–2.0 log10 CFU, compared to the control, except for marbofloxacin which reduced S. aureus biofilms by 5.4 log10 CFU. Two-antibiotic combinations did not improve, and even decreased, bacterial killing. In comparison, 5 min-exposure to 2% chlorhexidine reduced biofilms of the two tested strains by 4 log10 CFU. Our results showed that S. pseudintermedius and S. aureus biofilms were highly tolerant to all the drugs tested, consistent with the treatment failures observed in practice. Under our in vitro conditions, the use of chlorhexidine was more efficacious than antimicrobials to reduce S. pseudintermedius biofilm. PMID:27531995

  15. Comparison of the In vitro Activity of Five Antimicrobial Drugs against Staphylococcus pseudintermedius and Staphylococcus aureus Biofilms.

    Science.gov (United States)

    Ferran, Aude A; Liu, JingJing; Toutain, Pierre-Louis; Bousquet-Mélou, Alain

    2016-01-01

    Resistance in canine pathogenic staphylococci is necessitating re-evaluation of the current antimicrobial treatments especially for biofilm-associated infections. Long, repeated treatments are often required to control such infections due to the tolerance of bacteria within the biofilm. To comply with the goal of better antibiotic stewardship in veterinary medicine, the efficacies of the available drugs need to be directly assessed on bacterial biofilms. We compared the activities of amoxicillin, cefalexin, clindamycin, doxycycline, and marbofloxacin on in vitro biofilms of Staphylococcus pseudintermedius and Staphylococcus aureus. Exposure of biofilms for 15 h to maximum concentrations of the antibiotics achievable in canine plasma only reduced biofilm bacteria by 0.5-2.0 log10 CFU, compared to the control, except for marbofloxacin which reduced S. aureus biofilms by 5.4 log10 CFU. Two-antibiotic combinations did not improve, and even decreased, bacterial killing. In comparison, 5 min-exposure to 2% chlorhexidine reduced biofilms of the two tested strains by 4 log10 CFU. Our results showed that S. pseudintermedius and S. aureus biofilms were highly tolerant to all the drugs tested, consistent with the treatment failures observed in practice. Under our in vitro conditions, the use of chlorhexidine was more efficacious than antimicrobials to reduce S. pseudintermedius biofilm.

  16. STAPHYLOCOCCUS AUREUS NASAL CARRIAGE AMONG INJECTING AND NON-INJECTING DRUG USERS AND ANTIMICROBIAL SUSCEPTIBILITY

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    Mojtaba Varshochi

    2013-01-01

    Full Text Available Staphylococcus Aureus (SA is one of the most prevalent bacterial pathogens in human beings. Approximately 20% of healthy persons are persistent carriers and 60% are intermittent carriers of SA. Nasal cavity is one of the most important sites of its colonization. Intravenous (IV drug abuse has been proposed as a risk factor for colonization of SA in the nasal mucosa. The goal of this study was to determine the frequency of SA carriers in nasal cavity among IV and non-IV drug abusers (addicts, as well as to assess the antimicrobial susceptibility pattern of the positive cases. In a cross-sectional analysis of 300 drug addicts (Group I: 100 non-injecting addicts, Group II: 100 IV injecting drug addicts in rehab, Group III: 100 IV injecting drug addicts not in rehab in the infectious diseases clinics of Tabriz’s Imam Reza and Sina teaching hospitals and the rehabilitation center of Razi hospital, were investigated. Hospitalized addicts, insulin-dependent diabetic cases, HIV positive patients and those on chronic hemodialysis were excluded. The nasal mucosal sample was prepared from each case for SA isolation and its antimicrobial susceptibility was investigated by antibiogram. Eighty-four cases (28% were culture positive for SA, including 26 cases in group one, 32 cases in group two and 26 cases in group three (p = 0.55. There was only one MRSA isolate present in all the cases studied (1.2%. No resistance to linozolid, rifampin and vancomycin was observed. The resistance to erythromycin, cefoxitin, ciprofloxacin, clindamycin, co-trimoxazol and gentamicin were 3.6, 4.8, 2.4, 3.6, 1.2 and 2.4% respectively. No statistically significant differences existed between the three groups in antibacterial susceptibility pattern. Sensitivity to oxacillin using the E-test results and disc diffusion were completely consistent. The percentage of carries of SA in the anterior nasal mucosa among IV and non-IV drug addicts is not considerably higher than the

  17. Prevalence, genetic diversity, and antimicrobial susceptibility profiles of Staphylococcus aureus isolated from bovine mastitis in Zhejiang Province, China

    Institute of Scientific and Technical Information of China (English)

    Jian-ping LI; Hai-jian ZHOU; Lin YUAN; Ting HE; Song-hua HU

    2009-01-01

    This study was conducted to determine genetic diversity and antimicrobial susceptibility profiles of Staphylococcusaureus recovered from bovine mastitis in Zhejiang Province, China. Out of 3178 quarter milk samples from 846 lactating cows, among which 459 cows (54.3%) were found HMT positive, 890 quarters (28%) were found having subclinical mastitis. From 75 representative S. aureus isolates, 16 distinct types were identified by pulsed-field gel electrophoresis (PFGE). Four major PFGE types (A, B, C, and D) accounted for 82.7% of all isolates, and type A (41.3%) was observed in multiple herds across the studied areas. Each region was found to have a predominant type: Hangzhou type A (64.1%), Ningbo type C (34.5%) and type B (23.1%), Jinhua type D (53.3%), and Taizhou type C (62.5%). Results of antimicrobial susceptibility tests showed that 90.7% of the isolates were resistant to at least one antimicrobial. Resistance to penicillin and ampicillin (77.3%), tetracycline (60.0%), or erythromycin (48.0%) was observed. The bacteria resistant to multiple antibiotics such as penicillin, ampicillin, tetracycline, and erythromycin were commonly found. The information obtained from this study is useful for designing specific control programs for bovine S. aureus mastiffs in this region.

  18. Photodynamic antimicrobial chemotherapy (PACT) using phenothiazines derivatives associated with the red laser against staphylococcus aureus

    Science.gov (United States)

    Oliveira, Susana C. P. S.; Santos, Gustavo M. P.; Monteiro, Juliana S. C.; Miranda, Anderson F. S.; Sampaio, Fernando J. P.; Gesteira, Maria F. M.; Zanin, Fátima A. A.; Santos, Marcos A. V.; Pinheiro, Antônio L. B.

    2013-03-01

    The objective of this study was to evaluate the bactericidal effect of photodynamic antimicrobial chemotherapy (PACT) using phenothiazinium dye (Toluidine blue O and methylene blue) at a low concentration of 1μg/mL irradiated with the red laser at doses of 2.4 e 4.8 J/cm² on strain of Staphylococcus aureus (ATCC 23529) in vitro. For this research, tests were performed in triplicate and the samples were distributed into six test groups: (L-P-) Negative control (L1+P-) and (L2+P-) bacterial suspensions were irradiated with laser energy 2.4 and 4.8 J/cm2 respectively in the absence of photosensitizer; (L1+P+) and (L2+P+) bacterial suspensions were irradiated with laser in the presence of 1μg/ml of photosensitizer and finally (L-P+) bacterial suspensions only in the presence of phenothiazinium dye. Therefore, were analyzed the potential bactericidal PACT by counting of colony-forming units and analyzed statistically (ANOVA, Tukey test, p<0.05). The results showed that the negative control group when compared with laser group (L2+P-) it was observed a statistically significant increase (p<0.01) which L2+P- showed a higher number of CFU, on the other hand when compared to L1+P- no statistically significant difference was found, relation to the groups submitted to PACT, only showed a statistically significant reduction relative to the group irradiated L2+P+ (p<0.01) that showed a decrease in the number of CFU. There was no statistically significant difference between the groups submitted to PDT (L1+P+ and L2+P+). Although the results of this study have shown a reduction in average number of colony forming units by the appropriate laser-dye treatment combination, it needs further investigation.

  19. In vitro antimicrobial effects and mechanism of atmospheric-pressure He/O2 plasma jet on Staphylococcus aureus biofilm

    Science.gov (United States)

    Xu, Zimu; Shen, Jie; Cheng, Cheng; Hu, Shuheng; Lan, Yan; Chu, Paul K.

    2017-03-01

    The antimicrobial effects and associated mechanism of inactivation of Staphylococcus aureus (S. aureus) NCTC-8325 biofilms induced by a He/O2 atmospheric-pressure plasma jet (APPJ) are investigated in vitro. According to CFU (colony forming units) counting and the resazurin-based assay, the 10 min He/O2 (0.5%) APPJ treatment produces the optimal inactivation efficacy (>5 log10 ml‑1) against the S. aureus biofilm and 5% of the bacteria enter a viable but non-culturable (VBNC) state. Meanwhile, 94% of the bacteria suffer from membrane damage according to SYTO 9/PI counterstaining. Scanning electron microscopy (SEM) reveals that plasma exposure erodes the extracellular polymeric substances (EPS) and then the cellular structure. The H2DCFDA-stained biofilms show larger concentrations of intracellular reactive oxygen species (ROS) in membrane-intact bacteria with increasing plasma dose. The admixture of oxygen in the working gas highly contributes to the deactivation efficacy of the APPJ against S. aureus and the plasma-induced endogenous ROS may work together with the discharge-generated ROS to continuously damage the bacterial membrane structure leading to deactivation of the biofilm microbes.

  20. Antibody-directed targeting of lysostaphin adsorbed onto polylactide nanoparticles increases its antimicrobial activity against S. aureus in vitro

    Science.gov (United States)

    Satishkumar, R.; Vertegel, A. A.

    2011-12-01

    The objective of this paper was to study the effect of antibody-directed targeting of S. aureus by comparing the activities of lysostaphin conjugated to biodegradable polylactide nanoparticles (NPs) in the presence and in the absence of co-immobilized anti-S. aureus antibody. Lysostaphin-antibody-NP conjugates were synthesized through physical adsorption at different enzyme:antibody:NP ratios. The synthesized enzyme-NP conjugates were characterized by means of dynamic light scattering and zeta potential analysis, and the total protein binding yield on the NPs was characterized using Alexa Fluor 350 and 594 dyes for the S. aureus antibody and lysostaphin respectively. We observed enhanced antimicrobial activity for both enzyme-coated and enzyme-antibody-coated NPs for lysostaphin coatings corresponding to ~ 40% of the initial monolayer and higher compared to the free enzyme case (p < 0.05). At the highest antibody coating concentration, bacterial lysis rates for antibody-coated samples were significantly higher than for lysostaphin-coated samples lacking the antibody (p < 0.05). Such enzyme-NP conjugates thus have the potential for becoming novel therapeutic agents for treating antibiotic-resistant S. aureus infections.

  1. Rifampicin-fosfomycin coating for cementless endoprostheses: antimicrobial effects against methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA).

    Science.gov (United States)

    Alt, Volker; Kirchhof, Kristin; Seim, Florian; Hrubesch, Isabelle; Lips, Katrin S; Mannel, Henrich; Domann, Eugen; Schnettler, Reinhard

    2014-10-01

    New strategies to decrease infection rates in cementless arthroplasty are needed, especially in the context of the growing incidence of methicillin-resistant Staphylococcus aureus (MRSA) infections. The purpose of this study was to investigate the antimicrobial activity of a rifampicin-fosfomycin coating against methicillin-sensitive Staphylococcus aureus (MSSA) and MRSA in a rabbit infection prophylaxis model. Uncoated or rifampicin-fosfomycin-coated K-wires were inserted into the intramedullary canal of the tibia in rabbits and contaminated with an inoculation dose of 10(5) or 10(6) colony-forming units of MSSA EDCC 5055 in study 1 and MRSA T6625930 in study 2, respectively. After 28days the animals were killed and clinical, histological and microbiological assessment, including pulse-field gel electrophoresis, was conducted. Positive culture growth in agar plate testing and/or clinical signs and/or histological signs were defined positive for infection. Statistical evaluation was performed using Fisher's exact test. Both studies showed a statistically significant reduction of infection rates for rifampicin-fosfomycin-coated implants compared to uncoated K-wires (P=0.015). In both studies none of the 12 animals that were treated with a rifampicin-fosfomycin-coated implant showed clinical signs of infection or a positive agar plate testing result. In both studies, one animal of the coating group showed the presence of sporadic bacteria with concomitant inflammatory signs in histology. The control groups in both studies exhibited an infection rate of 100% with clear clinical signs of infection and positive culture growth in all animals. In summary, the rifampicin-fosfomycin-coating showed excellent antimicrobial activity against both MSSA and MRSA, and therefore warrants further clinical testing.

  2. Amphibian antimicrobial peptide fallaxin analogue FL9 affects virulence gene expression and DNA replication in Staphylococcus aureus

    DEFF Research Database (Denmark)

    Gottschalk, Sanne; Gottlieb, Caroline Trebbien; Vestergaard, Martin;

    2015-01-01

    antimicrobials. In the present study, the analogue FL9, based on the amphibian AMP fallaxin, was studied to elucidate its mode of action and antibacterial activity against the human pathogen Staphylococcus aureus. Our data showed that FL9 may have a dual mode of action against S. aureus. At concentrations around...... the MIC, FL9 bound DNA, inhibited DNA synthesis and induced the SOS DNA damage response, whereas at concentrations above the MIC the interaction between S. aureus and FL9 led to membrane disruption. The antibacterial activity of the peptide was maintained over a wide range of NaCl and MgCl2 concentrations......-encoded natural tolerance mechanisms included peptide cleavage and the addition of positive charge to the cell surface, both of which minimized the antimicrobial activity of FL9. Our results add new information about FL9 and its effect on S. aureus, which may aid in the future development of analogues...

  3. Antimicrobial drug use and infection control practices associated with the prevalence of methicillin-resistant Staphylococcus aureus in European hospitals.

    Science.gov (United States)

    MacKenzie, F M; Bruce, J; Struelens, M J; Goossens, H; Mollison, J; Gould, I M

    2007-03-01

    Major regional variations in the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) are observed across Europe. This study investigated hospital MRSA prevalence in relation to patterns of antimicrobial use and infection control policies in an observational, cross-sectional study that used retrospective data from 2001 and linear regression to model relationships. MRSA prevalence (median 20.8%, n = 173 hospitals) and antimicrobial consumption (median 55.2 defined daily doses/100 bed-days, n = 140 hospitals) both varied significantly according to geographical region (p antimicrobial consumption data were provided by 128 hospitals, and showed a strong statistical relationship between macrolide use and MRSA prevalence. Use of (i) third-generation cephalosporins, (ii) all antimicrobial agents, and (iii) all antimicrobial agents except glycopeptides was also associated with MRSA prevalence. Up to 146 hospitals provided data on MRSA prevalence and key infection control parameters. Adjusted linear regression modelling provided strong evidence that infection control policy recommendations associated with lower MRSA prevalence rates were (i) use of alcohol-based solutions for hand hygiene (mean difference 10.3%, 99% CI 1.2-10.3), and (ii) placement of MRSA patients in single rooms (mean difference 11.2%, 99% CI 1.4-20.9). Hospitals with problems in implementing isolation policies had higher resistance levels (mean difference 12%, 99% CI 3.8-20.1). Additional recommendations showed less evidence of association with a low MRSA prevalence. Overall, this study highlighted significant associations between MRSA prevalence, antimicrobial use and various key infection control parameters, all of which showed significant individual variations according to geographical region.

  4. Occurrence, Virulence Factors, Antimicrobial Resistance, and Genotyping of Staphylococcus aureus Strains Isolated from Chicken Products and Humans.

    Science.gov (United States)

    El Bayomi, Rasha M; Ahmed, Heba A; Awadallah, Maysa A I; Mohsen, Rasha A; Abd El-Ghafar, Abeer E; Abdelrahman, Mahmoud A

    2016-03-01

    Staphylococcus aureus in food is a consequence of inadequate hygienic handling and processing, posing a potential risk to public health. The current study aimed to characterize virulence factors, as well as antimicrobial resistance of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) isolated from retail chicken products and hand swabs from vendors in Egypt. In addition, genetic relatedness of the isolates from chicken and humans was evaluated by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) using protein A as a target. A total of 110 samples were collected from chicken products (n = 80) and vendors (n = 30). Overall, 30 (37.5%) chicken products samples were positive for S. aureus, whereas hand swabs from meat handlers revealed that 18 (60%) were positive. Ten MRSA strains were characterized by the presence of the mecA gene, comprising seven isolates from chicken and three from humans. Virulence-associated factors were evaluated by PCR, revealing that 31.3% of S. aureus isolates harbored the Panton-Valentine leukocidin (PVL) gene, whereas 10.4% were positive for the sea and sed genes each, and only two isolates were positive for γ-hemolysin-associated gene. Genotyping using spa PCR-RFLP showed identical restriction banding patterns of MRSA isolates of human and chicken meat origin, indicating the genetic relatedness of the isolates. To the best of our knowledge, this is the first study to characterize PVL-positive MRSA from chicken products and to utilize spa-RFLP for evaluating the genetic relatedness between MRSA of human and chicken origin in Egypt.

  5. Profile of antimicrobial susceptibility isolated microorganisms from hospitalized patients in PICU ward and detection of Methicillin-resistant Staphylococcus aureus and ESBL-producing bacteria by phenotypic methods

    Directory of Open Access Journals (Sweden)

    Shahla Abbas Poor

    2014-10-01

    Full Text Available Background: Hospital-acquired infections are a major challenge to patient. A range of gram-negative organisms are responsible for hospital-acquired infections, the Enterobacteriaceae family being the most commonly identified group overall. Infections by ESBL producers are associated with severe adverse clinical outcomes that have led to increased mortality, prolonged hospitalization, and rising medical costs. The aim of this study was to survey profile of antimicrobial susceptibility isolated microorganisms from hospitalized patients in PICU ward and detection of methicillin-resistant Staphylococcus aureus and ESBL-producing bacteria by phenotypic methods. Material and Methods: In this study participants were patients hospitalized in PICU part of Bahrami Hospital, Tehran, with attention to involved organ. For isolation of bacteria from patient’s samples, culture performed on different selective and differential media. After confirmation of bacteria by biochemical tests, susceptibility testing was performed by disc diffusion method. Phenotypic detection of MRSA strains was performed using cefoxcitin disc. ESBL producing strains were detected by ceftazidime (CAZ and ceftazidime/clavulanic acid (CAZ/CLA discs. Results: Among all isolated organisms from clinical samples, the most common isolated organisms were Escherichia coli (24 cases, Pseudomonas areoginosa (9 cases and Staphylococcus aureus (8 cases, respectively. Among eight MRSA isolated strains from different clinical samples, six strains (75% were MRSA. Among 52 isolated gram negative organisms, 5 strains (9/6% were ESBL. Conclusion: Standard interventions to prevent the transmission of antimicrobial resistance in health care facilities include hand hygiene, using barrier precautions in the care of colonized and infected patients, using dedicated instruments and equipment for these patients. The colonized or infected patients should be isolated in single rooms, multibed rooms or areas

  6. Host adaptation of bovine Staphylococcus aureus seems associated with bacteriological cure after lactational antimicrobial treatment

    NARCIS (Netherlands)

    Borne, van den B.H.P.; Nielen, M.; Schaik, van G.; Melchior, M.B.; Lam, T.J.G.M.; Zadoks, R.N.

    2010-01-01

    Staphylococcus aureus causes a wide range of diseases in multiple species. Some sequence types (ST) are observed in a variety of hosts, whereas other strains are mainly associated with bovine mastitis, suggesting host adaptation. We propose that host adaptation of Staph. aureus may influence bacteri

  7. Evaluation of the antimicrobial activity of chitosan and its quaternized derivative on E. coli and S. aureus growth

    Directory of Open Access Journals (Sweden)

    Rejane C. Goy

    2016-02-01

    Full Text Available Abstract Chitosan is largely known for its activity against a wide range of microorganisms, in which the most acceptable antimicrobial mechanism is found to include the presence of charged groups in the polymer backbone and their ionic interactions with bacteria wall constituents. This interaction suggests the occurrence of a hydrolysis of the peptidoglycans in the microorganism wall, provoking the leakage of intracellular electrolytes, leading the microorganism to death. The charges present in chitosan chains are generated by protonation of amino groups when in acid medium or they may be introduced via structural modification. This latter can be achieved by a methylation reaction resulting in a quaternized derivative with a higher polymeric charge density. Since the charges in this derivative are permanents, it is expected a most efficient antimicrobial activity. Hence, in the present study, commercial chitosan underwent quaternization processes and both (mother polymer and derivative were evaluated, in gel form, against Staphylococcus aureus (Gram-positive and Escherichia coli (Gram-negative, as model bacteria. The results, as acquired from turbidity measurements, differ between materials with an expressive reduction on the Gram-positive microorganism (S. aureus growth, while E. coli (Gram-negative strain was less sensitive to both polymers. Additionally, the antibacterial effectiveness of chitosan was strongly dependent on the concentration, what is discussed in terms of spatial polymer conformation.

  8. D-Amino Acids Enhance the Activity of Antimicrobials against Biofilms of Clinical Wound Isolates of Staphylococcus aureus and Pseudomonas aeruginosa

    Science.gov (United States)

    2014-05-19

    biofilm eradication concentration high-throughput (MBEC- HTP ) assay plates (Innovotech, Canada) for biofilm antimicrobial susceptibility test - ing (38, 39...susceptibility testing . M100-S22. CLSI, Wayne, PA. 38. Coraca-Huber DC, Fille M, Hausdorfer J, Pfaller K, Nogler M. 2012. Evaluation of MBEC- HTP biofilm model...Standards Institute (37). Test performance for antimicrobial agents was monitored using P. aerugi- nosa ATCC 27853 and S. aureus ATCC 29213 as control

  9. Comparison of the in vitro activity of five antimicrobial drugs on Staphylococcus pseudintermedius and Staphylococcus aureus biofilms

    Directory of Open Access Journals (Sweden)

    Aude A Ferran

    2016-08-01

    Full Text Available Resistance in canine pathogenic staphylococci is necessitating re-evaluation of the current antimicrobial treatments especially for biofilm-associated infections. Long, repeated treatments are often required to control such infections due to the tolerance of bacteria within the biofilm. To comply with the goal of better antibiotic stewardship in veterinary medicine, the efficacies of the available drugs need to be directly assessed on bacterial biofilms.We compared the activities of amoxicillin, cefalexin, clindamycin, doxycycline and marbofloxacin on in vitro biofilms of Staphylococcus pseudintermedius and Staphylococcus aureus. Exposure of biofilms for 15 hours to maximum concentrations of the antibiotics achievable in canine plasma only reduced biofilm bacteria by 0.5 to 2.0 log10 CFU, compared to the control, except for marbofloxacin which reduced S. aureus biofilms by 5.4 log10 CFU. Two-antibiotic combinations did not improve, and even decreased, bacterial killing. In comparison, 5 min-exposure to 2 % chlorhexidine reduced biofilms of the 2 tested strains by 4 log10 CFU. Our results showed that S. pseudintermedius biofilm, unlike S. aureus biofilm, was highly tolerant to all the drugs tested, consistent with the treatment failures observed in practice. Under our conditions, the use of topical chlorhexidine would probably be the best currently available strategy to reduce S. pseudintermedius biofilm.

  10. Genotypes, Virulence Factors and Antimicrobial Resistance Genes of Staphylococcus aureus Isolated in Bovine Subclinical Mastitis from Eastern China

    Directory of Open Access Journals (Sweden)

    Javed Memon§, Yongchun Yang§, Jam Kashifa, Muhammad Yaqoob, Rehana Buriroa, Jamila Soomroa, Wang Liping and Fan Hongjie*

    2013-11-01

    Full Text Available This study was carried out to determine the genotypes, virulence factors and antimicrobial resistance traits of 34 Staphylococcus aureus isolated from subclinical mastitis in Eastern China. Minimal inhibitory concentration (MIC results showed resistance to erythromycin in all isolates. A high frequency of Methicillin resistant S. aureus (MRSA; 29% was observed and these isolates were also highly resistant to penicillin, oxacillin, oxytetracycline and chloramphenicol than methicillin sensitive S. aureus (MSSA isolates. Thirteen pathogenic factors and seven resistance genes including mecA and blaZ gene were checked through PCR. The spaX gene was found in all isolates, whereas cna, spaIg, nuc, clfA, fnbpB, hlA, hlB and seA were present in 35, 79, 85, 59, 35, 85, 71 and 38% isolates, respectively. Nine isolates carried a group of 8 different virulence genes. Moreover, macrolide resistance genes ermB and ermC were present in all isolates. High resistance rate against methicillin was found but no isolate was positive for mecA gene, whereas blaZ and tetK were detected in 82 and 56% isolates, respectively. Genes; fnbpA, seB, seC, seD, dfrK and tetM were not found in any isolate. The statistical association between phenotypic resistance and virulence genes showed, clfA, fnbpB, hlB and seA, were potentially associated with penicillin G, ciprofloxacin, methicillin, chloramphenicol, trimethoprim and oxytetracycline resistance (P≤0.05. REP-PCR based genotyping showed seven distinct genotypes (A-G prevalent in this region. This study reports the presence of multidrug resistant S. aureus in sub-clinical mastitis which were also highly virulent that could be a major obstacle in the treatment of mastitis in this region of China.

  11. In vitro antimicrobial activity of honokiol against Staphylococcus aureus in biofilm mode.

    Science.gov (United States)

    Li, Wen-Li; Zhao, Xing-Chen; Zhao, Zi-Wen; Huang, Yan-Jun; Zhu, Xuan-Zhi; Meng, Ri-Zeng; Shi, Ce; Yu, Lu; Guo, Na

    2016-12-01

    Staphylococcus aureus (S. aureus) can attach to food, host tissues and the surfaces of medical implants and form a biofilm, which makes it difficult to eliminate. The purpose of this study was to evaluate the effect of honokiol on biofilm-grown S. aureus. In this report, honokiol showed effective antibacterial activity against S. aureus in biofilms. S. aureus isolates are capable of producing distinct types of biofilms mediated by polysaccharide intercellular adhesion (PIA) or extracellular DNA (eDNA). The biofilms' susceptibility to honokiol was evaluated using confocal laser scanning microscopy (CLSM) analysis. The transcript levels of the biofilm-related genes, the expression of PIA, and the amount of eDNA of biofilm-grown S. aureus exposed to honokiol were also investigated. The results of this study show that honokiol can detach existing biofilms, kill bacteria in biofilms, and simultaneously inhibit the transcript levels of sarA, cidA and icaA, eDNA release, and the expression of PIA.

  12. Genetic engineering of a temperate phage-based delivery system for CRISPR/Cas9 antimicrobials against Staphylococcus aureus

    Science.gov (United States)

    Park, Joo Youn; Moon, Bo Youn; Park, Juw Won; Thornton, Justin A.; Park, Yong Ho; Seo, Keun Seok

    2017-01-01

    Discovery of clustered, regularly interspaced, short palindromic repeats and the Cas9 RNA-guided nuclease (CRISPR/Cas9) system provides a new opportunity to create programmable gene-specific antimicrobials that are far less likely to drive resistance than conventional antibiotics. However, the practical therapeutic use of CRISPR/Cas9 is still questionable due to current shortcomings in phage-based delivery systems such as inefficient delivery, narrow host range, and potential transfer of virulence genes by generalized transduction. In this study, we demonstrate genetic engineering strategies to overcome these shortcomings by integrating CRISPR/Cas9 system into a temperate phage genome, removing major virulence genes from the host chromosome, and expanding host specificity of the phage by complementing tail fiber protein. This significantly improved the efficacy and safety of CRISPR/Cas9 antimicrobials to therapeutic levels in both in vitro and in vivo assays. The genetic engineering tools and resources established in this study are expected to provide an efficacious and safe CRISPR/Cas9 antimicrobial, broadly applicable to Staphylococcus aureus. PMID:28322317

  13. Selected Antimicrobial Essential Oils Eradicate Pseudomonas spp. and Staphylococcus aureus Biofilms

    OpenAIRE

    Kavanaugh, Nicole L.; Ribbeck, Katharina

    2012-01-01

    Biofilms are difficult to eliminate with standard antimicrobial treatments due to their high antibiotic resistance relative to free-living cells. Here, we show that selected antimicrobial essential oils can eradicate bacteria within biofilms with higher efficiency than certain important antibiotics, making them interesting candidates for the treatment of biofilms.

  14. The Global Challenge of Antimicrobial Resistance: Insights from Economic Analysis

    Directory of Open Access Journals (Sweden)

    Richard J. Zeckhauser

    2010-08-01

    Full Text Available The prevalence of antimicrobial resistance (AR limits the therapeutic options for treatment of infections, and increases the social benefit from disease prevention. Like an environmental resource, antimicrobials require stewardship. The effectiveness of an antimicrobial agent is a global public good. We argue for greater use of economic analysis as an input to policy discussion about AR, including for understanding the incentives underlying health behaviors that spawn AR, and to supplement other methods of tracing the evolution of AR internationally. We also discuss integrating antimicrobial stewardship into global health governance.The prevalence of antimicrobial resistance (AR limits the therapeutic options for treatment of infections, and increases the social benefit from disease prevention. Like an environmental resource, antimicrobials require stewardship. The effectiveness of an antimicrobial agent is a global public good. We argue for greater use of economic analysis as an input to policy discussion about AR, including for understanding the incentives underlying health behaviors that spawn AR, and to supplement other methods of tracing the evolution of AR internationally. We also discuss integrating antimicrobial stewardship into global health governance.

  15. The Challenges of Eliminating or Substituting Antimicrobial Preservatives in Foods.

    Science.gov (United States)

    Erickson, Marilyn C; Doyle, Michael P

    2017-02-28

    Consumers' criteria for evaluating food safety have evolved recently from considering the food's potential to cause immediate physical harm to considering the potential long-term effects that consumption of artificial ingredients, including antimicrobial preservatives, would have on health. As bacteriostatic and bactericidal agents to prevent microbial spoilage, antimicrobials not only extend shelf life, but they also enhance the product's safety. Antimicrobials and their levels that may be used in foods are specified by regulatory agencies. This review addresses the safety of antimicrobials and the potential consequences of removing those that are chemically synthesized or replacing them with antimicrobials from so-called natural sources. Such changes can affect the microbiological safety and spoilage of food as well as reduce shelf life, increase wastage, and increase the occurrence of foodborne illnesses.

  16. Antimicrobial photodynamic therapy in chronic osteomyelitis induced by Staphylococcus aureus: An in vitro and in vivo study

    Science.gov (United States)

    dos Reis Júnior, João Alves; de Assis, Patrícia Nascimento; Paraguassú, Gardênia Matos; de Vieira de Castro, Isabele Cardoso; Trindade, Renan Ferreira; Marques, Aparecida Maria Cordeiro; Almeida, Paulo Fernando; Pinheiro, Antônio Luiz Barbosa

    2012-09-01

    Osteomyelitis it is an acute or chronic inflammation in the marrow spaces in the superficial or cortical bone, and associated to bacterial infection. Chronic osteomyelitis represents a major health problem due to its difficult treatment and increased morbidity. Antimicrobial photodynamic therapy (APT) by laser is a treatment based on a cytotoxic photochemical reaction in which, a bright light produced by a laser system and an active photosensitizer absorbed by cells leads an activation that induces a series of metabolic reactions that culminates a bacterial killing. The aim of this study was to assess, both in vitro and in vivo, the effect of lethal laser photosensitization on osteomyelitis. On the in vitro study a diode laser (λ660nm; 40mW; o/ = 0.4 cm2; 5 or 10 J/cm2) and 5, 10 and 15μg/mL toluidine blue (TB) were tested and the best parameter chosen for the in vivo study. The concentration of 5μg/mL was selected to perform the decontamination of infected by Staphylococcus aureus tibial bone defects in rats. The results were performed by ANOVA test. On the in vitro studies all PDTs groups in the different concentrations reduced significantly (p<0,001) the amount of bacteria. On the in vivo study PDT group presented a bacterial reduction of 97,4% (P<0,001). The photodynamic therapy using toluidine blue was effective in reducing the staphiloccocus aureus in both in vitro and in vivo studies.

  17. Molecular characterization and antimicrobial susceptibility of nasal Staphylococcus aureus isolates from a Chinese medical college campus.

    Directory of Open Access Journals (Sweden)

    Jimei Du

    Full Text Available Staphylococcus aureus colonization and infection occur more commonly among persons living or working in crowded conditions, but characterization of S. aureus colonization within medical communities in China is lacking. A total of 144 (15.4%, 144/935 S. aureus isolates, including 28 (3.0%, 28/935 MRSA isolates, were recovered from the nares of 935 healthy human volunteers residing on a Chinese medical college campus. All S. aureus isolates were susceptible to vancomycin, quinupristin/dalfopristin and linezolid but the majority were resistant to penicillin (96.5%, ampicillin/sulbactam (83.3% and trimethoprim/sulfamethoxazole (93.1%. 82%, (23/28 of the MRSA isolates and 66% (77/116 of the MSSA isolates were resistant to multiple antibiotics, and 3 MRSA isolates were resistant to mupirocin--an agent commonly used for nasal decolonization. 16 different sequence types (STs, as well as SCCmec genes II, III, IVd, and V, were represented among MRSA isolates. We also identified, for the first time, two novel STs (ST1778 and ST1779 and 5 novel spa types for MRSA. MRSA isolates were distributed in different sporadic clones, and ST59-MRSA-VId- t437 was found within 3 MRSA isolates. Moreover, one isolate with multidrug resistance belonging to ST398-MRSA-V- t571 associated with animal infections was identified, and 3 isolates distributed in three different clones harbored PVL genes. Collectively, these data indicate a high prevalence of nasal MRSA carriage and molecular heterogeneity of S. aureus isolates among persons residing on a Chinese medical college campus. Identification of epidemic MRSA clones associated with community infection supports the need for more effective infection control measures to reduce nasal carriage and prevent dissemination of MRSA to hospitalized patients and health care workers in this community.

  18. Antimicrobial, Rheological, and Thermal Properties of Plasticized Polylactide Films Incorporated with Essential Oils to Inhibit Staphylococcus aureus and Campylobacter jejuni.

    Science.gov (United States)

    Ahmed, Jasim; Hiremath, Nikhil; Jacob, Harsha

    2016-02-01

    Polylactide (PLA) is the most mature biobased and biodegradable polymer. Due to its inherent brittleness, the polymer cannot be used as a packaging material without plasticizer. An attempt was made to develop antimicrobial plasticized PLA film by incorporating polyethylene glycol (PEG) and 3 essential oils (EO), namely cinnamon, garlic, and clove by solvent casting method. Physical, thermal, and rheological properties of those films were evaluated for practical applications whereas the antimicrobial properties were tested against Staphylococcus aureus and Campylobacter jejuni-pathogens related to poultry industry. Both PEG and EOs led to the formation of flexible PLA/PEG/EO films with significant drop in the glass transition temperature (Tg ), and mechanical property. Time-temperature superposition (TTS) principle was employed to melt rheology of EO-based films at selected temperature, and rheological moduli superimposed well in an extended frequency range. Among EOs, cinnamon and clove oil-based films (PLA/PEG/CIN and PLA/PEG/CLO) exhibited a complete zone of inhibition against C. jejuni at the maximum concentration (1.6 mL per 2 g PLA/PEG blend) whereas the garlic oil-based film (PLA/PEG/GAR) had the lowest activity.

  19. PHYTOCHEMICAL SCREENING, TLC FINGERPRINTING AND ANTIMICROBIAL ACTIVITY OF METHANOLIC LEAF EXTRACT OF ALOE VERA AGAINST CLINICAL ISOLATES OF METHICILLIN RESISTANT Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    HARINATHA REDDY A

    2016-02-01

    Full Text Available Objective: The present study was carried out to investigate phytochemical properties, Thin layer chromatography (TLC fingerprinting and antimicrobial activity of methanolic leaf extract of Aloe vera. Methods: A. vera leaves were collected, dried and powdered. The leaf powder was subjected to methanolic extraction. Preliminary phyotochemical screening done by using standard procedures. TLC studies of the methanol leaf extract of A. vera were carried out by using two different solvent systems. Solvent system I consist of Chloroform: Methanol (12:2 and solvent system II consist of Ethyl acetate: Toluene: Formic acid (2.2:1.1:1.1. The antibacterial activity of the methanolic leaf extract of A. vera was studied using disc diffusion method against Staphylococcus aureus ATCC 2592 and Methicillin Resistant Staphylococcus aureus (MRSA.Result: Preliminary phytochemical analysis of methanolic leaf extract of A. vera revealed that presence of carbohydrates, glycosides, amino acids, phenolic compounds, steroids, terpenoids, tannins, saponins, flavonoids and alkaloids. The Rf values of methanolic leaf extract in solvent system I is 0.66 and solvent system II is 0.42. The methanolic leaf extract of A. vera exhibited antimicrobial activity on S. aureus ATCC 25923 and MRSA. Maximum zone of inhibition was observed at 50 mg/ml of methanolic leaf extract of A. vera.Conclusion: The present results suggest that methanolic leaf extract of A. vera have significant antibacterial activity against Staphylococcus aureus ATCC 2592 and Methicillin Resistant Staphylococcus aureus (MRSA.

  20. Genome-Wide Identification of Antimicrobial Intrinsic Resistance Determinants in Staphylococcus aureus

    DEFF Research Database (Denmark)

    Vestergaard, Martin; Leng, Bingfeng; Haaber, Jakob

    2016-01-01

    The emergence of antimicrobial resistance severely threatens our ability to treat bacterial infections. While acquired resistance has received considerable attention, relatively little is known of intrinsic resistance that allows bacteria to naturally withstand antimicrobials. Gene products......, atpA, atpB, atpG and atpH, reduced the minimum inhibitory concentration (MIC) of gentamicin 16-fold. To elucidate the potential of the screen, we examined treatment efficacy in the Galleria mellonella infection model. Gentamicin efficacy was significantly improved, when treating larvae infected...

  1. Mutating the heme sensing response regulator HssR in Staphylococcus aureus but not in the Listeria monocytogenes homologue results in increased tolerance to the antimicrobial peptide Plectasin

    DEFF Research Database (Denmark)

    Thomsen, L. E.; Gottlieb, Caroline Trebbien; Gottschalk, S.;

    2010-01-01

    Background Host defence peptides (HDPs), also known as antimicrobial peptides (AMPs), have emerged as potential new therapeutics and their antimicrobial spectrum covers a wide range of target organisms. However, the mode of action and the genetics behind the bacterial response to HDPs is incomple......Background Host defence peptides (HDPs), also known as antimicrobial peptides (AMPs), have emerged as potential new therapeutics and their antimicrobial spectrum covers a wide range of target organisms. However, the mode of action and the genetics behind the bacterial response to HDPs...... constructed bacterial transposon mutant libraries of S. aureus NCTC8325-4 and L. monocytogenes 4446 and screened for increased resistance to the peptide. No resistant mutants arose when L. monocytogenes was screened on plates containing 5 and 10 fold Minimal Inhibitory Concentration (MIC) of plectasin...

  2. Antimicrobial Stewardship in the Emergency Department: Challenges, Opportunities, and a Call to Action for Pharmacists.

    Science.gov (United States)

    Bishop, Bryan M

    2016-12-01

    Antimicrobial resistance is a national public health concern. Misuse of antimicrobials for conditions such as upper respiratory infection, urinary tract infections, and cellulitis has led to increased resistance to antimicrobials commonly utilized to treat those infections, such as sulfamethoxazole/trimethoprim and flouroquinolones. The emergency department (ED) is a site where these infections are commonly encountered both in ambulatory patients and in patients requiring admission to a hospital. The ED is uniquely positioned to affect the antimicrobial use and resistance patterns in both ambulatory settings and inpatient settings. However, implementing antimicrobial stewardship programs in the ED is fraught with challenges including diagnostic uncertainty, distractions secondary to patient or clinician turnover, and concerns with patient satisfaction to name just a few. However, this review article highlights successful interventions that have stemmed inappropriate antimicrobial use in the ED setting and warrant further study. This article also proposes other, yet to be validated proposals. Finally, this article serves as a call to action for pharmacists working in antimicrobial stewardship programs and in emergency medicine settings. There needs to be further research on the implementation of these and other interventions to reduce inappropriate antimicrobial use to prevent patient harm and curb the development of antimicrobial resistance.

  3. Differential induction of innate defense antimicrobial peptides in primary nasal epithelial cells upon stimulation with inflammatory cytokines, Th17 cytokines or bacterial conditioned medium from Staphylococcus aureus isolates.

    Science.gov (United States)

    Burgey, Christine; Kern, Winfried V; Römer, Winfried; Rieg, Siegbert

    2016-01-01

    To date it is incompletely understood why half of the human population is intrinsically resistant to Staphylococcus aureus colonization whereas the other half is intermittently or permanently colonized. Nasal colonization represents the primary niche for S. aureus. We therefore investigated whether primary nasal epithelial cells (HNEC) express antimicrobial peptides (AMPs) upon stimulation by inflammatory cytokines or bacterial conditioned medium (BCM) of different colonizing and invasive staphylococci. Stimulation with classical cytokines (IL-1β, TNF-α, IFN-γ) potently induced hBD-3 and RNase7 in HNEC. Th17 cytokines (IL-17A, IL-17F, IL-22) yielded comparably weak hBD-3 and RNase7 induction and no synergistic effects with classical cytokines. BCM of S. aureus and Staphylococcus epidermidis isolates moderately induced hBD3 and RNase7 mRNA expression without significant differences when comparing colonizing vs. invasive isolates. Our results indicate that HNEC contribute to the innate defense by secretion of an AMP-containing chemical defense shield along the nasal mucosa i.e. within the primary colonization niche of S. aureus. Further studies are needed to investigate whether a deficient AMP expression in the nasal mucosa may be related to different S. aureus carrier states. AMPs or AMP-inducing agents may be promising candidates for future topical decolonization regimens that aim to prevent invasive S. aureus infections.

  4. Antimicrobial susceptibility of Staphylococcus aureus isolated from bovine mastitis in Europe and the United States

    DEFF Research Database (Denmark)

    De Oliveira, A. P.; Watts, J. L.; Salmon, S. A.;

    2000-01-01

    (123), Switzerland (69), United States (53), and Zimbabwe (6). The antimicrobial agents tested were penicillin, ampicillin, oxacillin, cephalothin, ceftiofur, amoxicillin + clavulanate, penicillin + novobiocin, enrofloxacin, premafloxacin, erythromycin, clindamycin, lincomycin, pirlimycin, neomycin......, lincomycin + neomycin, and sulfamethazine. The MIC90 for these antimicrobial agents for all strains were 0.5, 1.0, 1.0, 0.5, 1.0, less than or equal to 0.06, 0.125, 0.125, less than or equal to 0.0078, 0.5, 1.0, 16.0, 1.0, 2.0, 0.5, and 4.0 mu g/ml, respectively. Overall, only small variations between...

  5. Epidemiology of Methicillin-Resistant Staphylococcus aureus Diabetic Foot Infections in a Large Academic Hospital: Implications for Antimicrobial Stewardship

    Science.gov (United States)

    Moore, Robert J.; Hand, Elizabeth O.; Howell, Crystal K.

    2016-01-01

    Introduction Diabetic foot infections (DFIs) are the leading cause of non-traumatic lower extremity amputations in the United States. Antimicrobials active against methicillin-resistant Staphylococcus aureus (MRSA) are recommended in patients with associated risk factors; however, limited data exist to support these recommendations. Due to the changing epidemiology of MRSA, and the consequences of unnecessary antibiotic therapy, guidance regarding the necessity of empirical MRSA coverage in DFIs is needed. We sought to 1) describe the prevalence of MRSA DFIs at our institution and compare to the proportion of patients who receive MRSA antibiotic coverage and 2) identify risk factors for MRSA DFI. Methods This was a retrospective cohort study of all adult, culture-positive DFI patients managed at University Hospital, San Antonio, TX between January 1, 2010 and September 1, 2014. Patient eligibility included a principal ICD-9-CM discharge diagnosis code for foot infection and a secondary diagnosis of diabetes. The primary outcome was MRSA identified in the wound culture. Independent variables assessed included patient demographics, comorbidities, prior hospitalization, DFI therapies, prior antibiotics, prior MRSA infection, and laboratory values. Multivariable logistic regression was used to identify risk factors for MRSA DFI. Results Overall, 318 patients met inclusion criteria. Patients were predominantly Hispanic (79%) and male (69%). Common comorbidities included hypertension (76%), dyslipidemia (52%), and obesity (49%). S. aureus was present in 46% of culture-positive DFIs (MRSA, 15%). A total of 273 patients (86%) received MRSA antibiotic coverage, resulting in 71% unnecessary use. Male gender (OR 3.09, 95% CI 1.37–7.99) and bone involvement (OR 1.93, 1.00–3.78) were found to be independent risk factors for MRSA DFI. Conclusions Although MRSA was the causative pathogen in a small number of DFI, antibiotic coverage targeted against MRSA was unnecessarily

  6. Short communication: Antimicrobial efficacy of intramammary treatment with a novel biphenomycin compound against Staphylococcus aureus, Streptococcus uberis, and Escherichia coli-induced mouse mastitis.

    Science.gov (United States)

    Demon, Dieter; Breyne, Koen; Schiffer, Guido; Meyer, Evelyne

    2013-01-01

    Bovine mastitis undermines udder health, jeopardizes milk production, and entails prohibitive costs, estimated at $2 billion per year in the dairy industry of the United States. Despite intensive research, the dairy industry has not managed to eradicate the 3 major bovine mastitis-inducing pathogens: Staphylococcus aureus, Streptococcus uberis, and Escherichia coli. In this study, the antimicrobial efficacy of a newly formulated biphenomycin compound (AIC102827) was assessed against intramammary Staph. aureus, Strep. uberis, and E. coli infections, using an experimental mouse mastitis model. Based on its effective and protective doses, AIC102827 applied into the mammary gland was most efficient to treat Staph. aureus, but also adequately reduced growth of Strep. uberis or E. coli, indicating its potential as a broad-spectrum candidate to treat staphylococcal, streptococcal, and coliform mastitis in dairy cattle.

  7. Antimicrobial effect of sour pomegranate sauce on Escherichia coli O157:H7 and Staphylococcus aureus.

    Science.gov (United States)

    Kışla, Duygu; Karabıyıklı, Şeniz

    2013-05-01

    Pomegranate sauce is one of the most popular pomegranate products produced in Turkey. This study was conducted to determine the minimum inhibitory concentrations (MICs) of both traditional and commercial sour pomegranate sauce samples on Staphylococcus aureus (ATCC 25923) and Escherichia coli O157:H7 (ATCC 43895). The initial microflora of the pomegranate sauce samples was determined by performing the enumerations of total aerobic mesophilic bacteria, yeast and mold, S. aureus, E. coli, and the determination of Salmonella spp. MIC tests were applied to the neutralized and the original (unneutralized) sour pomegranate sauce samples in order to put forth the inhibition effect depending on low pH value. It was found that inhibitory effect of the traditional and the commercial samples, except one sample, on pathogens was not only due to the acidity of the products. The results of MIC tests indicated that although both traditional and commercial samples showed a considerable inhibitory effect on test microorganisms, the traditional pomegranate sauce samples were more effective than the commercial ones.

  8. Antimicrobial use metrics and benchmarking to improve stewardship outcomes: methodology, opportunities, and challenges.

    Science.gov (United States)

    Ibrahim, Omar M; Polk, Ron E

    2014-06-01

    Measurement of antimicrobial use before and after an intervention and the associated outcomes are key activities of antimicrobial stewardship programs. In the United States, the recommended metric for aggregate antibiotic use is days of therapy/1000 patient-days. Clinical outcomes, including response to therapy and bacterial resistance, are critical measures but are more difficult to document than economic outcomes. Interhospital benchmarking of risk adjusted antimicrobial use is possible, although several obstacles remain before it can have an impact on patient care. Many challenges for stewardship programs remain, but the methods and science to support their efforts are rapidly evolving.

  9. Antimicrobial peptide exposure selects for Staphylococcus aureus resistance to human defence peptides

    DEFF Research Database (Denmark)

    Kubicek-Sutherland, Jessica Z.; Lofton, Hava; Vestergaard, Martin

    2017-01-01

    of LL-37, PR-39 or wheat germ histones. WGS and proteomic analysis by MS were used to identify the molecular mechanism associated with increased tolerance of AMPs. AMP-resistant mutants were characterized by measuring in vitro fitness, AMP and antibiotic susceptibility, and virulence in a mouse model...... of sepsis. Results: AMP-resistant Staphylococcus aureus mutants often displayed little to no fitness cost and caused invasive disease in mice. Further, this phenotype coincided with diminished susceptibility to both clinically prescribed antibiotics and human defence peptides. Conclusions: These findings...... suggest that therapeutic use of AMPs could select for virulent mutants with crossresistance to human innate immunity as well as antibiotic therapy. Thus, therapeutic use of AMPs and the implications of cross-resistance need to be carefully monitored and evaluated....

  10. In Vitro Susceptibility of Methicillin-Resistant Staphylococcus aureus and Methicillin-Susceptible Staphylococcus aureus to a New Antimicrobial, Copper Silicate▿

    OpenAIRE

    2007-01-01

    The soluble copper silicate (CS) MIC of 100 strains of methicillin-resistant Staphylococcus aureus and 100 strains of methicillin-susceptible S. aureus (MSSA) was 175 mg Cu/liter. Bactericidal and postantibiotic effects (≥1 h) were seen at 2× MIC and 4× MIC. The frequency of mutation was

  11. Mastitis Bovina: Resistencia a antibióticos de cepas de Staphylococcus aureus asiladas de leche (Bovine Mastitis: Antimicrobial resistance of Staphylococcus aureus strains isolated from milk

    Directory of Open Access Journals (Sweden)

    Pellegrino, MS

    2011-07-01

    Full Text Available ResumenLa mastitis bovina es considerada la enfermedad infecciosa del ganado lechero de mayor impacto económico mundial, siendo Staphylococcus aureus el principal agente patógeno en muchos países.SummaryBovine mastitis is a frequent cause of economic loss in worldwide dairy herds, being Staphylococcus aureus the main etiological agent in many countries.

  12. Mastitis Bovina: Resistencia a antibióticos de cepas de Staphylococcus aureus asiladas de leche (Bovine Mastitis: Antimicrobial resistance of Staphylococcus aureus strains isolated from milk)

    OpenAIRE

    Pellegrino, MS; Frola, ID; Odierno, LM; Bogni, CI

    2011-01-01

    ResumenLa mastitis bovina es considerada la enfermedad infecciosa del ganado lechero de mayor impacto económico mundial, siendo Staphylococcus aureus el principal agente patógeno en muchos países.SummaryBovine mastitis is a frequent cause of economic loss in worldwide dairy herds, being Staphylococcus aureus the main etiological agent in many countries.

  13. Antimicrobial effect of an ultrasonic levitation washer disinfector with silver electrolysis and ozone oxidation on methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Tamai, Mariko; Matsushita, Shigeto; Miyanohara, Hiroaki; Imuta, Naoko; Ikeda, Ryuji; Kawai, Kazuhiro; Nishi, Junichiro; Sakamoto, Akihiro; Shigihara, Takanori; Kanekura, Takuro

    2013-12-01

    Methicillin-resistant Staphylococcus aureus (MRSA) has rapidly emerged as a cause of severe and intractable skin infection. At present, there are no effective topical treatments, and infection or colonization by MRSA of the skin raises serious medical problems. We developed an ultrasonic levitation washer that generates silver ions (Ag(+)) and ozone (O3) to clean and sterilize medical devices. We report the effect of ultrasonic levitation (levitation) with Ag(+) and O3 on MRSA in vitro and in vivo. Antimicrobial effect against six MRSA strains of all agr types was examined under three in vitro conditions; cells floating in a water tank, cells infiltrating-, and cells forming a biofilm on an atelocollagen membrane. In the in vivo studies, we assayed the number of MRSA organisms that survived treatment on murine skin ulcers and evaluated the ulcer size. Levitation with Ag(+) dramatically decreased the survival of MRSA floating in a water tank. Levitation with Ag(+) and O3 significantly decreased the viability of MRSA that had infiltrated or formed a biofilm on atelocollagen membranes regardless of the level of biofilm production. In vivo studies showed that the number of MRSA on murine skin ulcers was significantly decreased when 15-min treatment was performed for 7 consecutive days and that the ulcer size was significantly decreased after the seventh treatment course. Levitation with Ag(+) and O3 may be a valuable tool for treating MRSA infestation of the skin and for accelerating wound healing.

  14. In vitro activity of lauric acid or myristylamine in combination with six antimicrobial agents against methicillin-resistant Staphylococcus aureus (MRSA).

    Science.gov (United States)

    Kitahara, Takashi; Aoyama, Yuko; Hirakata, Yoichi; Kamihira, Shimeru; Kohno, Shigeru; Ichikawa, Nobuhiro; Nakashima, Mikiro; Sasaki, Hitoshi; Higuchi, Shun

    2006-01-01

    The objective of this study was to investigate the in vitro activities of lauric acid and myristylamine in combination with six antimicrobial agents against methicillin-resistant Staphylococcus aureus (MRSA). The combination effect of lipids and antimicrobial agents was evaluated by the checkerboard method to obtain a fractional inhibitory concentration (FIC) index. The effects of lauric acid + gentamicin (GM) and lauric acid + imipenem (IPM) combinations were synergistic against the clinical isolates in 12 combinations. An antagonistic FIC index was observed only with the myristylamine + GM combination. We investigated in detail the antimicrobial activity for two combinations that showed a synergistic effect. The cytotoxicity of lauric acid was not enhanced by the addition of GM and IPM. In time-kill studies, lauric acid + GM and lauric acid + IPM combinations at one-eighth of the minimum inhibitory concentration produced a bacteriostatic effect.

  15. Frequency of resistance to methicillin and other antimicrobial agents among Staphylococcus aureus strains isolated from pigs and their human handlers in Trinidad

    Directory of Open Access Journals (Sweden)

    Annika Gordon

    2014-04-01

    Full Text Available 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

  16. Antimicrobial activity of green tea extract against isolates of methicillin-resistant Staphylococcus aureus and multi-drug resistant Pseudomonas aeruginosa

    Institute of Scientific and Technical Information of China (English)

    Maksum Radji; Rafael Adi Agustama; Berna Elya; Conny Riana Tjampakasari

    2013-01-01

    Objective: To evaluate antibacterial activity of the Indonesian water soluble green tea extract,Camellia sinensis, against clinical isolates of methicillin-resistant Staphylococcus aureus (S. aureus) (MRSA) and multi-drug resistant Pseudomonas aeruginosa (MDR-P. aeruginosa). Methods:Antimicrobial activity of green tea extract was determined by the disc diffusion method and the minimum inhibitory concentration (MIC) was determined by the twofold serial broth dilutions method. The tested bacteria using in this study were the standard strains and multi-drug resistant clinical isolates of S. aureus and P. aeruginosa, obtained from Laboratory of Clinical Microbiology, Faculty of Medicine, University of Indonesia. Results:The results showed that the inhibition zone diameter of green tea extracts for S. aureus ATCC 25923 and MRSA were (18.970±0.287) mm, and (19.130±0.250) mm respectively. While the inhibition zone diameter for P. aeruginosa ATCC 27853 and MDR-P. aeruginosa were (17.550±0.393) mm and (17.670±0.398) mm respectively. The MIC of green tea extracts against S. aureus ATCC 25923 and MRSA were 400 µg/mL and 400 µg/mL, respectively, whereas the MIC for P. aeruginosa ATCC 27853 and MDR-P. aeruginosa were 800 µg/mL, and 800 µg/mL, respectively. Conclusions: Camellia sinensis leaves extract could be useful in combating emerging drug-resistance caused by MRSA and P. aeruginosa.

  17. Antimicrobial Resistance Patterns of Acinetobacter baumannii, Pseudomonas aeruginosa and Staphylococcus aureus Isolated From Patients With Nosocomial Infections Admitted to Tehran Hospitals

    Directory of Open Access Journals (Sweden)

    Fallah

    1970-01-01

    Full Text Available Background Nosocomial infections constitute a global health problem, leading to a high rate of morbidity and mortality. The choice of antimicrobial treatment for nosocomial infections is often empirical and based on the knowledge of local antimicrobial activity patterns of the most common bacteria causing such infections. Objectives The aim of this study was to determine the 3 most prevalent bacterial pathogens including Acinetobacter baumannii, Pseudomonas aeruginosa and Staphylococcus aureus causing nosocomial infections and their antimicrobial resistant profiles in patients admitted to three hospitals in Tehran city, Iran. Materials and Methods In this cross-sectional study, the A. baumannii, P. aeruginosa and S. aureus isolates were obtained from different samples of patients with nosocomial infections admitted to different wards of three hospitals including Milad, Motahary and Loghman from November 2014 to April 2015. Nosocomial infections were defined as a culture-proven infection, which occurred more than 48 hours after admission. Antimicrobial susceptibility testing was performed using the disk diffusion method according to Clinical and Laboratory Standards Institute (CLSI guidelines. Results In total, 539 samples were collected during the study period from patients with nosocomial infections. Overall, 198, 75 and 98 A. baumannii, P. aeruginosa and S. aureus isolates were obtained, respectively. Cefepim and meropenem were found to be the most effective antibiotics for nosocomial infections caused by S. aureus with only 1 resistant isolate. Resistance to gentamicin and amikacin and susceptibility to cefepim was the highest compared to other antibiotics amongst P. aeruginosa isolates which is in consistent with the fact that cephalosporins remain useful agents for the management of nosocomial infections caused by P. aeruginosa. Acinetobacter baumannii isolates showed lower susceptibility rates to imipenem and ciprofloxacin than other

  18. Antimicrobial Activities of TiO2 Nanoparticle Against Escherichia coli and Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    F Barzegary

    2010-04-01

    Full Text Available Introduction: Organic antibacterial materials have been used as insecticides and bactericides for many years. Unfortunately, high temperatures in manufacturing process reduce their antibacterial properties. However, inorganic materials of antibacterial agents have excellent bacterial resistance and thermal stability. Over the past few decades, inorganic nanoparticles whose structures exhibit significantly novel and improved physical, chemical and biological properties and functionality due to their nano-scale size have elicited much interest. methods:The aim of this study was to investigate the antibacterial properties of one kind of nano-specimen (TiO2 nanoparticle against Escherichia coli and Streptococcus aureus. Our study was research perusal. In the first study, the optical density of E. coli and S. aureus cultures were observed in the presence of 0.01%, 0.75% and 1.5% of TiO2. In the second study, 6.3 log CFU/ml of E. coli and S. areus were separately exposed to 1.5% TiO2 at 37 ºC in water. In third study, we studied thew growth of E.coli in solid medium with and without nanoparticles. Results: The presence of 0.01% TiO2 nanoparticles didn’t have a statistically significant effect, but in the presence of 0.75% and 1.5% nanoparticles, the bacterial colonies decreased significantly. In the control group, bacterial cells survival was nearly 13 days, while complete cell death of E. coli was seen when 1.5% TiO2 was applied for 24 hours. The same experiment for S. aureu, showed that complete cell death occured when the bacterial culture was exposed to 1.5% TiO2 for 16 hours.. It was shown that presence of 1.5% TiO2 in the solid medium suppressed the growth of E. coli 5.6 times more (p < 0.001. Discussion: Our findings showed antibacterial effects of TiO2 nanoparticles against both bacteria, but S. areus bacteria were more sensitive to nanoparticles as compared to E. coli bacteria

  19. Phytochemical Properties of Mentha longifolia L. Essential Oil and its Antimicrobial Effects on Staphylococcus Aureus

    Directory of Open Access Journals (Sweden)

    R Mahmodi

    2011-12-01

    Full Text Available Background & Aim: Due to the side effects of chemical and synthetic preservatives, consumers have recently become more eager to use foods containing natural preservatives from plants, animals and microbial sources. In the present study, biochemical composition and antibacterial effects (MIC of Mentha longifolia L. essential oil against Staphylococcus aureus have been evaluated. Methods: In this experimental study, the biochemical composition and antibacterial prosperities of this essential oil was determined by the Gas chromatography/ mass spectrophotometer (GC/MS and micro dilution method respectively. The morphological and membrane changes of the bacterial cell under the effect of this essential oil were evaluated by transmission electron microscopy. The collected data was analyzed by the SPSS software using ANOVA. Results: The chemical analysis of the essential oil by Gas chromatography/ mass spectrophotometer (GC/MS revealed the presence of 22 substances (95.30%, mainly including Pulegon (31.54%, 1,8 Cineol (15.89%, Menthoforan (11.8% and Cis- Isopulegon (9.74%. Minimum inhibitory concentration of the essential oil determined under different temperature and pH values showed to be in the range of 75-1200 µg/ ml. Conclusion: The MIC results and membrane cell damage observed in the electron microscopy evaluation indicated that this essential oil have a high antibacterial activity. Therefore, this essential oil can be combined with other agents for the preservation of foods against pathogenic and toxigenic microorganisms.

  20. Development of a rapid diagnostic method for identification of Staphylococcus aureus and antimicrobial resistance in positive blood culture bottles using a PCR-DNA-chromatography method.

    Science.gov (United States)

    Ohshiro, Takeya; Miyagi, Chihiro; Tamaki, Yoshikazu; Mizuno, Takuya; Ezaki, Takayuki

    2016-06-01

    Blood culturing and the rapid reporting of results are essential for infectious disease clinics to obtain bacterial information that can affect patient prognosis. When gram-positive coccoid cells are observed in blood culture bottles, it is important to determine whether the strain is Staphylococcus aureus and whether the strain has resistance genes, such as mecA and blaZ, for proper antibiotic selection. Previous work led to the development of a PCR method that is useful for rapid identification of bacterial species and antimicrobial susceptibility. However, that method has not yet been adopted in community hospitals due to the high cost and methodological complexity. We report here the development of a quick PCR and DNA-chromatography test, based on single-tag hybridization chromatography, that permits detection of S. aureus and the mecA and blaZ genes; results can be obtained within 1 h for positive blood culture bottles. We evaluated this method using 42 clinical isolates. Detection of S. aureus and the resistance genes by the PCR-DNA-chromatography method was compared with that obtained via the conventional identification method and actual antimicrobial susceptibility testing. Our method had a sensitivity of 97.0% and a specificity of 100% for the identification of the bacterial species. For the detection of the mecA gene of S. aureus, the sensitivity was 100% and the specificity was 95.2%. For the detection of the blaZ gene of S. aureus, the sensitivity was 100% and the specificity was 88.9%. The speed and simplicity of this PCR-DNA-chromatography method suggest that our method will facilitate rapid diagnoses.

  1. HPTLC fingerprint profile, in vitro antioxidant and evaluation of antimicrobial compound produced from Brevibacillus brevis-EGS9 against multidrug resistant Staphylococcus aureus.

    Science.gov (United States)

    Arumugam, T; Senthil Kumar, P; Gopinath, K P

    2017-01-01

    In the present study, in vitro antimicrobial activity of Brevibacillus brevis EGS9 against multi drug resistant Staphylococcus aureus (MDRSA) and to investigate the antimicrobial, antioxidant activity and HPTLC finger print profile of Brevibacillus brevis EGS9. Primary screening was done using by cross streak method against multi drug resistant Staphylococcus aureus. The bioactive metabolites were extracted from Brevibacillus brevis EGS9 using ethyl acetate extraction. Ethyl acetate extract showed significant antimicrobial activity against Escherichia coli (20.2 ± 0.1) mm, Candida albicans (19.2 ± 0.3) mm and Bacillus cereus (18.6 ± 0.2) mm respectively. Forty three UTI bacterial strains were isolated from mid-urine samples of 50 males and 50 females. Escherichia coli were more predominant (48%) followed by Klebsilla pneumonia (29%), Pseudomonas aeruginosa (17%), Staphylococcus aureus (4%) and Enterobacter faecalis (6%). The ethyl acetate extract was examined to evaluate antibacterial properties against isolated UTIs bacterial pathogens. The results were revealed that the maximum zone was measured in Escherichia coli (18.1 ± 0.4) mm and minimum zone of inhibition was shown against Pseudomonas aeruginosa (10.6 ± 0.3) mm. Based on the results obtained, the extract of Brevibacillus brevis EGS9 exhibited dose dependent manner of antioxidant activity. The DPPH scavenging activity of lowest concentration at 25 μg/ml and high concentration at 1000 μg/ml was measured at 2.4% and 39.5% respectively. HPTLC finger print profile was showed the active compounds present in crude extract, which may responsible for the antioxidant prospective. These results showed that, the significant antimicrobial properties against pathogen; this work will be helpful to explore the active compound identification in the field of pharmaceutical research and able to produce new drug molecules against pathogens.

  2. In Vitro susceptibility of methicillin-resistant Staphylococcus aureus and methicillin-susceptible Staphylococcus aureus to a new antimicrobial, copper silicate.

    Science.gov (United States)

    Carson, Kerry C; Bartlett, Jessica G; Tan, Trina-Jean; Riley, Thomas V

    2007-12-01

    The soluble copper silicate (CS) MIC of 100 strains of methicillin-resistant Staphylococcus aureus and 100 strains of methicillin-susceptible S. aureus (MSSA) was 175 mg Cu/liter. Bactericidal and postantibiotic effects (> or =1 h) were seen at 2x MIC and 4x MIC. The frequency of mutation was <10(-9), and serial passage could not extend growth beyond 1.6x MIC.

  3. Emerging Infectious Diseases, Antimicrobial Resistance and Millennium Development Goals: Resolving the Challenges through One Health

    Directory of Open Access Journals (Sweden)

    G. V. Asokan

    2014-01-01

    Full Text Available Most emerging infectious diseases are zoonoses, which could severely hamper reaching the targets of millennium development goals (MDG. Five out of the total eight MDG’s are strongly associated with the Emerging Infectious Diseases (EIDs. Recent emergence and dissemination of drug-resistant pathogens has accelerated and prevent reaching the targets of MDG, with shrinking of therapeutic arsenal, mostly due to antimicrobial resistance (AMR. World Health Organization (WHO has identified AMR as 1 of the 3 greatest threats to global health. Until now, methicillin-resistant staphylococcus aureus (MRSA and vancomycin-resistant enterococci (VRE have been observed in hospital-acquired infections. In India, within a span of three years, New Delhi metallo-β-lactamase prevalence has risen from three percent in hospitals to twenty- fifty percent and is found to be colistin resistant as well. Routine use of antimicrobials in animal husbandry accounts for more than 50% in tonnage of all antimicrobial production to promote growth and prophylaxis. This has consequences to human health and environmental contamination with a profound impact on the environmental microbiome, resulting in resistance. Antibiotic development is now considered a global health crisis. The average time required to receive regulatory approval is 7.2 years. Moreover, the clinical approval success is only 16%. To overcome resistance in antimicrobials, intersectoral partnerships among medical, veterinary, and environmental disciplines, with specific epidemiological, diagnostic, and therapeutic approaches are needed. Joint efforts under “One Health”, beyond individual professional boundaries are required to stop antimicrobial resistance against zoonoses (EID and reach the MDG.

  4. Antimicrobial activity of PVP from an Antarctic bacterium, Janthinobacterium sp. Ant5-2, on multi-drug and methicillin resistant Staphylococcus aureus

    KAUST Repository

    Huang, Jonathan P.

    2012-04-11

    Multiple drug resistant (MDR) and methicillin-resistant Staphylococcus aureus (MRSA) have become increasingly prevalent as a community acquired infection. As a result limited treatment options are available with conventional synthetic antibiotics. Bioprospecting natural products with potent antimicrobial activity show promise for developing new drugs against this pathogen. In this study, we have investigated the antimicrobial activity of a purple violet pigment (PVP) from an Antarctic bacterium, Janthinobacterium sp. Ant5-2 on 15 clinical MDR and MRSA strains. The colorimetric resazurin assay was employed to determine the minimum inhibitory concentration (MIC90) of PVP against MDR and MRSA. The MIC90 ranged between 1.57 µg/mL and 3.13 µg/mL, which are significantly lower than many antimicrobials tested from natural sources against this pathogen. The spectrophotometrically determined growth analysis and total microscopic counts using Live/dead® BacLight™ fluorescent stain exhibited a steady decrease in viability of both MDR and MRSA cultures following treatment with PVP at the MIC levels. In silico predictive molecular docking study revealed that PVP could be a DNA-targeting minor groove binding antimicrobial compound. The continued development of novel antimicrobials derived from natural sources with the combination of a suite of conventional antibiotics could stem the rising pandemic of MDR and MRSA along with other deadly microbial pathogens.

  5. Combination of analytical and microbiological techniques to study the antimicrobial activity of a new active food packaging containing cinnamon or oregano against E. coli and S. aureus.

    Science.gov (United States)

    Becerril, R; Gómez-Lus, R; Goñi, P; López, P; Nerín, C

    2007-07-01

    The aim of this work is the optimization and application of a group of analytical and microbiological techniques in the study of the activity of essential oils (EOs) incorporated in a new antimicrobial packaging material and the research in depth of the interaction between the microbial cells and the individual compounds present in the active material. For this purpose the antimicrobial activity of the active packaging containing cinnamon or oregano was evaluated against E. coli and S. aureus. The vapour phase activity and the direct contact between the antimicrobial agents themselves, or once incorporated in the packaging material, and the microbial cells have been studied. The direct contact was studied using a broth dilution method. The vapour phase was evaluated by using a new method which involves the use of a filter disk containing the EOs. Furthermore, the kill time assay was used to determine the exposure time for the maximum efficiency in packaging, and transmission electron microscopy was used to investigate the antimicrobial activity and the possible mechanism of action against E. coli and S. aureus. Finally, the compounds absorbed by cells were identified. The results showed that the techniques used provide relevant information about the antibacterial activity of cinnamon and oregano in direct contact as well as in the vapour phase. The antimicrobial packaging showed a fast efficiency which supports its likely application as a food packaging material. Bacteria treated with EOs exhibit a wide range of significant abnormalities; these include formation of blebs, coagulation of cytoplasmatic constituents, collapse of the cell structure and lack of cytoplasmatic material. Some of these observations are correlated to the ability of some of these substances to disrupt envelop structure, especially the inner membrane. After an extraction from dead cells, cinnamaldehyde was detected by GC-MS in E. coli exposed to the active packaging containing cinnamon.

  6. Genetic lineages, antimicrobial resistance, and virulence in Staphylococcus aureus of meat samples in Spain: analysis of immune evasion cluster (IEC) genes.

    Science.gov (United States)

    Benito, Daniel; Gómez, Paula; Lozano, Carmen; Estepa, Vanesa; Gómez-Sanz, Elena; Zarazaga, Myriam; Torres, Carmen

    2014-05-01

    The objective of this study was to determine the rate of contamination by Staphylococcus aureus in 100 meat samples obtained during 2011-2012 in La Rioja (Northern Spain), to analyze their content in antimicrobial resistance and virulence genes, as well as in immune evasion cluster (IEC) genes, and to type recovered isolates. Seven of 100 samples (7%) contained S. aureus: 6 samples harbored methicillin-susceptible S. aureus (MSSA) and 1 pork sample harbored methicillin-resistant S. aureus (MRSA). The MRSA isolate corresponded to the ST398 genetic lineage with a multidrug resistance profile and the absence of human IEC genes, which pointed to a typical livestock-associated MRSA profile. MRSA isolate was ascribed to the spa-type t011, agr-type I, and SCCmec-V and showed resistance to erythromycin, clindamycin, tetracycline, and streptomycin, in addition to β-lactams. The remaining six MSSA strains belonged to different sequence types and clonal complexes (three isolates ST45/CC45, one ST617/CC45, one ST5/CC5, and one ST109/CC9), being susceptible to most antibiotics tested but showing a wide virulence gene profile. Five of the six MSSA strains (except ST617/CC45) contained the enterotoxin egc-cluster or egc-like-cluster genes, and strain ST109/CC9 contained eta gene (encoding exfoliatin A). The presence of human IEC genes in MSSA strains (types B and D) points to a possible contamination of meat samples from an undefined human source. The presence of S. aureus with enterotoxin genes and MRSA in food samples might have implications in public health. The IEC system could be a good marker to follow the S. aureus contamination source in meat food products.

  7. Antibiotic Exposure and Other Risk Factors for Antimicrobial Resistance in Nasal Commensal Staphylococcus aureus: An Ecological Study in 8 European Countries.

    Directory of Open Access Journals (Sweden)

    Evelien M E van Bijnen

    Full Text Available Antimicrobial resistance (AMR has become a global public health concern which threatens the effective treatment of bacterial infections. Resistant Staphylococcus aureus (including MRSA increasingly appears in individuals with no healthcare associated risks. Our study assessed risk factors for nasal carriage of resistant S. aureus in a multinational, healthy, community-based population, including ecological exposure to antibiotics.Data were collected in eight European countries (Austria, Belgium, Croatia, France, Hungary, the Netherlands, Spain and Sweden. Commensal AMR patterns were assessed by collecting 28,929 nasal swabs from healthy persons (aged 4+. Ecological exposure to antibiotics was operationalized as systemic antibiotic treatment patterns, extracted from electronic medical records of primary care practices in which the participants were listed (10-27 per country. A multilevel analysis related AMR in nasal commensal S. aureus to antibiotic exposure and other risk factors (e.g. age and profession.Of the 6,093 S. aureus isolates, 77% showed resistance to at least one antibiotic. 7.1% exhibited multidrug resistance (defined as resistance to 3 or more antibiotic classes, and we found 78 cases MRSA (1.3%. A large variation in antibiotic exposure was found between and within countries. Younger age and a higher proportion of penicillin prescriptions in a practice were associated with higher odds for carriage of a resistant S. aureus. Also, we found higher multidrug resistance rates in participants working in healthcare or nurseries.This study indicates that in a population with no recent antibiotic use, the prescription behavior of the general practitioner affects the odds for carriage of a resistant S. aureus, highlighting the need for cautious prescribing in primary care. Finally, since variation in AMR could partly be explained on a national level, policy initiatives to decrease AMR should be encouraged at the national level within Europe.

  8. Methicillin-Resistant "Staphylococcus aureus" on Campus: A New Challenge to College Health

    Science.gov (United States)

    Weiner, H. Richard

    2008-01-01

    As new drugs to control bacterial pathogens are developed, the organisms evolve to survive. "Staphylococcus aureus", a common organism, has steadily developed resistance to antibiotics. For more than 40 years, resistant "S. aureus" presented a formidable problem to hospitalized patients; in the past decade, however, it has begun to appear outside…

  9. Future challenges and treatment of Staphylococcus aureus bacteremia with emphasis on MRSA

    DEFF Research Database (Denmark)

    Rasmussen, Rasmus V; Fowler, Vance G; Skov, Robert;

    2011-01-01

    . Compounding this problem is the growing prevalence of methicillin-resistant S. aureus (MRSA) and the dwindling efficacy of vancomycin, long the treatment of choice for this pathogen. Despite the recent availability of several new antibiotics for S. aureus, new strategies for treatment and prevention...

  10. Antimicrobial activity of Hibiscus sabdariffa aqueous extracts against Escherichia coli O157:H7 and Staphylococcus aureus in a microbiological medium and milk of various fat concentrations.

    Science.gov (United States)

    Higginbotham, Kristen L; Burris, Kellie P; Zivanovic, Svetlana; Davidson, P Michael; Stewart, C Neal

    2014-02-01

    Hibiscus sabdariffa L. calyces are widely used in the preparation of beverages. The calyces contain compounds that exhibit antimicrobial activity, yet little research has been conducted on their possible use in food systems as antimicrobials. Aqueous extracts prepared from the brand "Mi Costenita" were sterilized by membrane filtration (0.22-μm pore size) or autoclaving (121 °C, 30 min) and tested for antimicrobial activity against the foodborne pathogens Escherichia coli O157:H7 strains ATCC 43894 and Cider and Staphylococcus aureus strains SA113 and ATCC 27708 in a microbiological medium and ultrahigh-temperature-processed milk with various fat percentages. Extracts heated by autoclaving exhibited greater activity than did filtered extracts in a microbiological medium. Against E. coli, results of 20 mg/ml filtered extract were not different from those of the control, whereas autoclaved extracts reduced viable cells ca. 3 to 4 log CFU/ml. At 60 mg/ml, both extracts inactivated cells after 24 h. There were reduced populations of both strains of S. aureus (ca. 2.7 and 3 log CFU/ml, respectively) after 24 h of incubation in 40 mg/ml filtered extracts. When grown in autoclaved extracts at 40 mg/ml, both strains of S. aureus were inactivated after 9 h. Autoclaved extracts had decreased anthocyanin content (2.63 mg/liter) compared with filtered extracts (14.27 mg/liter), whereas the phenolic content (48.7 and 53.8 mg/g) remained similar for both treatments. Autoclaved extracts were then tested for activity in milk at various fat concentrations (skim [3.25%]) against a 1:1 mixture of the two strains of E. coli O157:H7 and a 1:1 mixture of the two strains of S. aureus. Extracts at 40 mg/ml inactivated S. aureus after 168 h in skim and whole milk, and E. coli was inactivated after 96 h in 60 mg/ml extract in all fat levels. These findings show the potential use of Hibiscus extracts to prevent the growth of pathogens in foods and beverages.

  11. Antimicrobial peptides effectively kill a broad spectrum of Listeria monocytogenes and Staphylococcus aureus strains independently of origin, sub-type, or virulence factor expression

    DEFF Research Database (Denmark)

    Gottlieb, Caroline Trebbien; Thomsen, L.E.; Ingmer, H.;

    2008-01-01

    ) to the human β-defensin 3 (HBD-3). All strains were inhibited by concentrations of hydrogen peroxide between 0.1% – 1.0%. Sub-selections of both species differed in expression of several virulence-related factors and in their ability to survive in human whole blood and kill the nematode virulence model...... Caenorhabditis elegans. For L. monocytogenes, proliferation in whole blood was paralleled by high invasion in Caco-2 cells and fast killing of C. elegans, however, no such pattern in phenotypic behavior was observed for S. aureus and none of the phenotypic differences were correlated to sensitivity to HDPs......Background Host defense peptides (HDPs), or antimicrobial peptides (AMPs), are important components of the innate immune system that bacterial pathogens must overcome to establish an infection and HDPs have been suggested as novel antimicrobial therapeutics in treatment of infectious diseases...

  12. [Determination of the antimicrobial capacity of green tea (Camellia sinensis) against the potentially pathogenic microorganisms Escherichia coli, Salmonella enterica, Staphylococcus aureus, Listeria monocytogenes, Candida albicans and Aspergillus niger].

    Science.gov (United States)

    Mora, Andreína; Pawa, Jonathan; Chaverri, José M; Arias, María Laura

    2013-09-01

    Many studies can be found in scientific literature demonstrating the antimicrobial capacity of different herbs, including green tea. Never-theless, many results are divergent or cannot be compared. Several green tea formulations may be found in market, but there is scarce or non-information about its activity. In this work, the potential antimicrobial effect of 50 samples of dry green tea and in 10% infusion against Escherichia coli, Salmonella enterica, Listeria monocytogenes, Staphylococcus aureus, Candida albicans and Aspergillus niger distributed in the metropolitan area of Costa Rica, was determined. This activity was compared with the effect produced by Chinese origin green tea (Camellia sinensis). Different solvents were evaluated for preparing polyphenol enriched extracts from green tea samples. Total phenols were determined using the Folin-Ciocalteu spectrophotometric methodology, using galic acid as reference. Antimicrobial activity of green tea extracts and infusions was evaluated using the microplate methodology described by Breuking (2006). Ethanol was the most efficient solvent used for the polyphenol extractions. There was no antimicrobial effect of the different green tea extracts and infusions against the microorganisms evaluated, except for Listeria monocytogenes, where the extracts of 70% of samples analyzed and the control showed an inhibitory effect in the 10.5 mg/mL and 1.05 mg/L concentrations. None of the infusions tested, including the control, showed any effect against this bacteria.

  13. Photodynamic antimicrobial chemotherapy (PACT) using phenothiazines derivatives associated with the red-orange LED against staphylococcus aureus

    Science.gov (United States)

    Monteiro, Juliana S. C.; Oliveira, Susana C. P. S.; Santos, Gustavo M. P.; Miranda, Anderson F. S.; Sampaio, Fernando J. P.; Gesteira, Maria F. M.; Zainn, Fátima A. A.; Santos, Marcos A. V.; Pinheiro, Antônio L. B.

    2013-03-01

    The objective of this study was to contribute to PDT development by researching alternative light sources using redorange LED light at doses of 2.4 e 4.8 J/cm2 to evaluate the bactericidal effect of photodynamic antimicrobial chemotherapy (PACT) using phenothiazinium dye (Toluidine blue O and methylene blue) at a low concentration of 1μg/mL on strain of Staphylococcus aureus (ATCC 23529) in vitro. For this research, tests were performed in triplicate and the samples were distributed into six test groups: (L-P-) Negative control (L1+ P-) and (L2+ P-) bacterial suspensions were irradiated with laser energy 2.4 and 4.8 J/cm2 respectively in the absence of photosensitizer; (L1 + P+) and (L2 + P+) bacterial suspensions were irradiated with laser in the presence of 1μg/ml of photosensitizer and finally (L-P+) bacterial suspensions only in the presence of phenothiazinium dye. Therefore, were analyzed the potential bactericidal PACT by counting of colony-forming units and analyzed statistically (ANOVA, Tukey test, p<0.05). The results demonstrated that comparing the LED group (L2 + P-) with negative control group, LED group (L1+ P-) and photosensitizer group there was a statistically significant (p<0.0001, p<0.01 and p<0.001, respectively) that the group treated only with LED (energy density of 4.8J/cm2) increased the average of CFU counts. The negative control group when compared to the groups submitted to PDT only showed a statistically significant reduction (p<0.01) relative to the group (L2+P+) that showed a decrease in the number of CFU. There was no statistically significant difference between the groups submitted to PDT (L1+P+ and L2+P+). Although the results of this study have shown a reduction in average number of colony forming units by the appropriate LED-dye treatment combination, it needs further investigation.

  14. Nosocomial Infections: Multicenter surveillance of antimicrobial resistance profile of Staphylococcus aureus and Gram negative rods isolated from blood and other sterile body fluids in Iran

    Directory of Open Access Journals (Sweden)

    Bahman Poorabbas

    2015-11-01

    Full Text Available Background and Objective: Antibiotic resistance is increasing, especially in healthcare-associated infections causing significant public health concerns worldwide. National information is required to make appropriate policies, update list of essential drugs for treatment, and evaluate the effects of intervention strategies. A nationwide surveillance of antimicrobial resistant bacteria in nosocomial infections was established in Iran in 2008, so that the data obtained through the surveillance would enable us to construct a database.Materials and Methods: Seven major teaching hospitals in Shiraz, Tabriz, Sari, Mashhad, Sanandaj, Ahwaz and Isfahan participated in this study. A total of 858 strains isolated from blood and other sterile body fluids were tested. Identification at the species level was performed with conventional biochemical methods and the API system. Susceptibility tests were done using disk diffusion method. The methicillin-resistance in S. aureus (MRSA was determined by the oxacillin agar screen plate and respective MIC values were assessed using the E-test strips. The confirmatory disk diffusion methods were applied for phenotypic identification of extended-spectrum β- lactamase (ESBL production for E. coli and K. pneumoniae, according to CLSI guidelines.Results: Cultivation and re-identification of the strains yielded 858 isolates, consisting of 224 S. aureus, 148 Klebsiellaspp., 105 Serratia spp., 146 E. coli, 67 Acinetobacter spp., 38 Enterobacter spp., 95 Pseudomonas spp., 71 P.aeruginosa.35 Stenotrophomonas sp., and 8 other organisms. MRSA was detected in 37.5% of the isolates. No vancomycin-resistant or vancomycin-intermediate resistant S. aureus was detected. With the exception of Acinetobacter and Stenotrophomonas, 85% of the Gram-negative isolates were found to be susceptible in vitro to imipenem. Overall, about 61% of K. pneumoniae and 35% of E. coli isolates were ESBL producing.Conclusion: Multidrug resistant isolates

  15. Current and future antimicrobial treatment of gonorrhoea - the rapidly evolving Neisseria gonorrhoeae continues to challenge.

    Science.gov (United States)

    Unemo, Magnus

    2015-08-21

    Neisseria gonorrhoeae has developed antimicrobial resistance (AMR) to all drugs previously and currently recommended for empirical monotherapy of gonorrhoea. In vitro resistance, including high-level, to the last option ceftriaxone and sporadic failures to treat pharyngeal gonorrhoea with ceftriaxone have emerged. In response, empirical dual antimicrobial therapy (ceftriaxone 250-1000 mg plus azithromycin 1-2 g) has been introduced in several particularly high-income regions or countries. These treatment regimens appear currently effective and should be considered in all settings where local quality assured AMR data do not support other therapeutic options. However, the dual antimicrobial regimens, implemented in limited geographic regions, will not entirely prevent resistance emergence and, unfortunately, most likely it is only a matter of when, and not if, treatment failures with also these dual antimicrobial regimens will emerge. Accordingly, novel affordable antimicrobials for monotherapy or at least inclusion in new dual treatment regimens, which might need to be considered for all newly developed antimicrobials, are essential. Several of the recently developed antimicrobials deserve increased attention for potential future treatment of gonorrhoea. In vitro activity studies examining collections of geographically, temporally and genetically diverse gonococcal isolates, including multidrug-resistant strains particularly with resistance to ceftriaxone and azithromycin, are important. Furthermore, understanding of effects and biological fitness of current and emerging (in vitro induced/selected and in vivo emerged) genetic resistance mechanisms for these antimicrobials, prediction of resistance emergence, time-kill curve analysis to evaluate antibacterial activity, appropriate mice experiments, and correlates between genetic and phenotypic laboratory parameters, and clinical treatment outcomes, would also be valuable. Subsequently, appropriately designed

  16. EARSS: European Antimicrobial Resistance Surveillance System; data from the Netherlands .Incidence and resistance rates for Streptococcus pneumoniae and Staphylococcus aureus

    NARCIS (Netherlands)

    Goettsch WG; de Neeling AJ; CIE; LIO

    2001-01-01

    Gevoeligheid voor antimicrobiele middelen in Streptococcus pneumoniae en Staphylococcus aureus werd bepaald in 1999 in Nederland binnen het raamwerk van het European antomicrobial Resistance Surveillance System (EARSS). Het EARSS project had in Nederland een dekkingsgraad van 40% van de Nederlandse

  17. Clinical impact of antimicrobial resistance in European hospitals: excess mortality and length of hospital stay related to methicillin-resistant Staphylococcus aureus bloodstream infections.

    LENUS (Irish Health Repository)

    de Kraker, Marlieke E A

    2011-04-01

    Antimicrobial resistance is threatening the successful management of nosocomial infections worldwide. Despite the therapeutic limitations imposed by methicillin-resistant Staphylococcus aureus (MRSA), its clinical impact is still debated. The objective of this study was to estimate the excess mortality and length of hospital stay (LOS) associated with MRSA bloodstream infections (BSI) in European hospitals. Between July 2007 and June 2008, a multicenter, prospective, parallel matched-cohort study was carried out in 13 tertiary care hospitals in as many European countries. Cohort I consisted of patients with MRSA BSI and cohort II of patients with methicillin-susceptible S. aureus (MSSA) BSI. The patients in both cohorts were matched for LOS prior to the onset of BSI with patients free of the respective BSI. Cohort I consisted of 248 MRSA patients and 453 controls and cohort II of 618 MSSA patients and 1,170 controls. Compared to the controls, MRSA patients had higher 30-day mortality (adjusted odds ratio [aOR] = 4.4) and higher hospital mortality (adjusted hazard ratio [aHR] = 3.5). Their excess LOS was 9.2 days. MSSA patients also had higher 30-day (aOR = 2.4) and hospital (aHR = 3.1) mortality and an excess LOS of 8.6 days. When the outcomes from the two cohorts were compared, an effect attributable to methicillin resistance was found for 30-day mortality (OR = 1.8; P = 0.04), but not for hospital mortality (HR = 1.1; P = 0.63) or LOS (difference = 0.6 days; P = 0.96). Irrespective of methicillin susceptibility, S. aureus BSI has a significant impact on morbidity and mortality. In addition, MRSA BSI leads to a fatal outcome more frequently than MSSA BSI. Infection control efforts in hospitals should aim to contain infections caused by both resistant and susceptible S. aureus.

  18. Establishing quality control ranges for antimicrobial susceptibility testing of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus: a cornerstone to develop reference strains for Korean clinical microbiology laboratories.

    Science.gov (United States)

    Hong, Sung Kuk; Choi, Seung Jun; Shin, Saeam; Lee, Wonmok; Pinto, Naina; Shin, Nari; Lee, Kwangjun; Hong, Seong Geun; Kim, Young Ah; Lee, Hyukmin; Kim, Heejung; Song, Wonkeun; Lee, Sun Hwa; Yong, Dongeun; Lee, Kyungwon; Chong, Yunsop

    2015-11-01

    Quality control (QC) processes are being performed in the majority of clinical microbiology laboratories to ensure the performance of microbial identification and antimicrobial susceptibility testing by using ATCC strains. To obtain these ATCC strains, some inconveniences are encountered concerning the purchase cost of the strains and the shipping time required. This study was focused on constructing a database of reference strains for QC processes using domestic bacterial strains, concentrating primarily on antimicrobial susceptibility testing. Three strains (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) that showed legible results in preliminary testing were selected. The minimal inhibitory concentrations (MICs) and zone diameters (ZDs) of eight antimicrobials for each strain were determined according to the CLSI M23. All resulting MIC and ZD ranges included at least 95% of the data. The ZD QC ranges obtained by using the CLSI method were less than 12 mm, and the MIC QC ranges extended no more than five dilutions. This study is a preliminary attempt to construct a bank of Korean QC strains. With further studies, a positive outcome toward cost and time reduction can be anticipated.

  19. Enhancement of antimicrobial activities of whole and sub-fractionated white tea by addition of copper (II sulphate and vitamin C against Staphylococcus aureus; a mechanistic approach

    Directory of Open Access Journals (Sweden)

    Holloway Andrew C

    2011-11-01

    Full Text Available Abstract Background Enhancement of antimicrobial plant products e.g. pomegranate extract by copper (II sulphate is known. Such combinations have applications in various settings, including the identification of novel compositions to study, treat and control infection. Methods A combination of white tea (WT (made allowing 10 minutes infusion time at 100°C was combined with 4.8 mM copper (II sulphate and tested for antimicrobial effect on the viability of Staphylococcus aureus NCTC 06571. Comparisons were made with green (GT and black (BT teas. A WT sub-fraction (WTF Results A 30 minute incubation at room temperature of copper (II sulphate alone and combined with WT reduced the viability of S. aureus NCTC 06571 by c.a 1 log10 cfu mL-1. GT and BT with copper (II sulphate negated activity to buffer values. Combined with copper (II sulphate, vitamin C, WTF and, vitamin C plus WTF all reduced the viability of S. aureus NCTC 06571 by c.a. 3.5 log10 cfu mL-1. Independent experiments showed the results were not due to pH effects. Adding WT or WTF to copper (II sulphate resulted in increased acidity. Copper (II sulphate alone and combined with WT required c.a 300 μg mL-1 (final concentration catalase to restore S. aureus viability, WTF with copper (II sulphate and added vitamin C required c.a 600 μg mL-1. WT and WTF UV-visible spectra were similar. Conclusions WT showed no efficacy in the combinations tested. WTF was enhanced with copper (II sulphate and further with vitamin C. WT and WTF increased acidity of copper (II sulphate possibly via the formation of chemical complexes. The difference in WT/WTF absorbance possibly represented substances less concentrated or absent in WTF. Investigations to establish which WTF component/s and in what proportions additives are most effective against target organisms are warranted.

  20. In vitro susceptibility of Staphylococcus aureus strains isolated from cows with subclinical mastitis to different antimicrobial agents

    Science.gov (United States)

    Schlenker, Gerd; Szabo, Istvan; Roesler, Uwe

    2012-01-01

    Sensitivity to commercial teat dips (nonoxinol-9 iodine complex and chlorhexidine digluconate) of 56 Staphylococcus (S.) aureus strains isolated from quarter milk samples of various German dairy herds treated with different teat dipping schemes was investigated in this study. The minimum inhibitory concentration was determined using a broth macrodilution method according to the German Veterinary Association guidelines. The main objective of the current study was to induce in vitro resistance induction of S. aureus to chemical disinfectants. Ten different strains were repeatedly passed ten times in growth media with sub-lethal concentrations of disinfectants. Nine strains showed a significant reduction in susceptibility to the nonoxinol-9 iodine complex but only one strain developed resistance to chlorhexidine digluconate. Stability of the acquired resistance was observed in all S. aureus strains adapted to the nonoxinol-9 iodine complex and chlorhexidine digluconate. In contrast, simultaneous resistance to different antibiotics was not observed in any of the ten investigated S. aureus strains. However, the isolates exhibited a high degree of resistance to penicillin G. Based on these results, resistance of S. aureus to chemical disinfectants may be more likely to develop if the chemicals are used at concentrations lower than that required for an optimal biocidal effect. PMID:22705737

  1. The antimicrobial lysine-peptoid hybrid LP5 inhibits DNA replication and induces the SOS response in Staphylococcus aureus

    DEFF Research Database (Denmark)

    Gottschalk, Sanne; Ifrah, Dan; Lerche, Sandra

    2013-01-01

    ABSTRACT: BACKGROUND: The increase in antibiotic resistant bacteria has led to renewed interest in development of alternative antimicrobial compounds such as antimicrobial peptides (AMPs), either naturally-occurring or synthetically-derived. Knowledge of the mode of action (MOA) of synthetic...... compounds mimicking the function of AMPs is highly valuable both when developing new types of antimicrobials and when predicting resistance development. Despite many functional studies of AMPs, only a few of the synthetic peptides have been studied in detail. RESULTS: We investigated the MOA of the lysine...

  2. Comparison of the antimicrobial activity of Ulmo honey from Chile and Manuka honey against methicillin-resistant Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Sherlock Orla

    2010-09-01

    Full Text Available Abstract Background Honey has previously been shown to have wound healing and antimicrobial properties, but this is dependent on the type of honey, geographical location and flower from which the final product is derived. We tested the antimicrobial activity of a Chilean honey made by Apis mellifera (honeybee originating from the Ulmo tree (Eucryphia cordifolia, against selected strains of bacteria. Methods Ulmo 90 honey was compared with manuka UMF® 25+ (Comvita® honey and a laboratory synthesised (artificial honey. An agar well diffusion assay and a 96 well minimum inhibitory concentration (MIC spectrophotometric-based assay were used to assess antimicrobial activity against five strains of methicillin-resistant Staphylococcus aureus (MRSA, Escherichia coli and Pseudomonas aeruginosa. Results Initial screening with the agar diffusion assay demonstrated that Ulmo 90 honey had greater antibacterial activity against all MRSA isolates tested than manuka honey and similar activity against E. coli and P. aeruginosa. The MIC assay, showed that a lower MIC was observed with Ulmo 90 honey (3.1% - 6.3% v/v than with manuka honey (12.5% v/v for all five MRSA isolates. For the E. coli and Pseudomonas strains equivalent MICs were observed (12.5% v/v. The MIC for artificial honey was 50% v/v. The minimum bactericidal concentration for all isolates tested for Ulmo 90 honey was identical to the MIC. Unlike manuka honey, Ulmo 90 honey activity is largely due to hydrogen peroxide production. Conclusions Due to its high antimicrobial activity, Ulmo 90 may warrant further investigation as a possible alternative therapy for wound healing.

  3. In vitro activity against Staphylococcus aureus of a novel antimicrobial agent, PRF-119, a recombinant chimeric bacteriophage endolysin.

    Science.gov (United States)

    Idelevich, Evgeny A; von Eiff, Christof; Friedrich, Alexander W; Iannelli, Domenico; Xia, Guoqing; Peters, Georg; Peschel, Andreas; Wanninger, Ingrid; Becker, Karsten

    2011-09-01

    Antistaphylococcal activity of the novel chimeric endolysin PRF-119 was evaluated with the microdilution method. The MIC(50) and MIC(90) of 398 methicillin-susceptible Staphylococcus aureus isolates were 0.098 μg/ml and 0.391 μg/ml, respectively (range, 0.024 to 0.780 μg/ml). Both the MIC(50) and MIC(90) values of 776 methicillin-resistant S. aureus isolates were 0.391 μg/ml (range, 0.024 to 1.563 μg/ml). All 192 clinical isolates of coagulase-negative staphylococci exhibited MIC values of >50 μg/ml. In conclusion, PRF-119 exhibited very good activity specifically against S. aureus.

  4. Antimicrobial Activity of Geranium Oil against Clinical Strains of Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Monika Sienkiewicz

    2012-08-01

    Full Text Available The aim of this work was to investigate the antibacterial properties of geranium oil obtained from Pelargonium graveolens Ait. (family Geraniaceae, against one standard S. aureus strain ATCC 433000 and seventy clinical S. aureus strains. The agar dilution method was used for assessment of bacterial growth inhibition at various concentrations of geranium oil. Susceptibility testing of the clinical strains to antibiotics was carried out using the disk-diffusion and E-test methods. The results of our experiment showed that the oil from P. graveolens has strong activity against all of the clinical S. aureus isolates—including multidrug resistant strains, MRSA strains and MLSB-positive strains—exhibiting MIC values of 0.25–2.50 μL/mL.

  5. A 5-year survey of antimicrobial susceptibility profiles of methicillin-resistant Staphylococcus aureus (MRSA) isolated from patients with bloodstream infections in Northeast Italy.

    Science.gov (United States)

    Cojutti, Piergiorgio; Scarparo, Claudio; Sartor, Assunta; Coato, Paola; Rigoli, Roberto; Pea, Federico

    2015-01-01

    A 5-year survey (2009-2013) of antimicrobial susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) isolated from patients with bloodstream infections was carried out in Northeast Italy. No upward creep of glycopeptides MICs was documented among 582 nonduplicate MRSA blood isolates, which were tested in accordance with broth microdilution and interpreted in accordance with EUCAST recommendations. Teicoplanin showed stably a lower MIC50 in comparison with vancomycin (0.25-0.5 versus 1 mg/L). The activities of newer anti-MRSA antibacterials stratified by glycopeptides MICs showed similar trends in MICs of either vancomycin or teicoplanin with those of daptomycin, linezolid, and tigecycline. We hypothesize that in centers with different distribution of glycopeptides MICs, downward for teicoplanin and upward for vancomycin, teicoplanin could be a more effective alternative to vancomycin for empirical treatment of MRSA-related bacteremia.

  6. Variant innate immune responses of mammary epithelial cells to challenge by Staphylococcus aureus, Escherichia coli and the regulating effect of taurine on these bioprocesses.

    Science.gov (United States)

    Zheng, Liuhai; Xu, Yuanyuan; Lu, Jinye; Liu, Ming; Bin Dai; Miao, Jinfeng; Yin, Yulong

    2016-07-01

    Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) are important pathogens causing subclinical and clinical bovine mastitis, respectively. Taurine, an organic acid found in animal tissues, has been used for the treatment of various superficial infections and chronic inflammations. We challenged a bovine mammary epithelial cell (MEC) line (MAC-T) or a mouse mammary epithelial cell line (EpH4-Ev) with either E. coli or S. aureus and compared the responses of MECs to these 2 pathogens. We also examined the regulatory effects of taurine on these responses. Receptor analyses showed that both TLR2 and TLR4 are upregulated upon exposure to either E. coli or S. aureus. Taurine pre-treatment dampened upregulation to some extent. E. coli and S. aureus stimulated comparable levels of ROS, which could be inhibited by taurine pre-treatment. E. coli infection elicited a dramatic change in iNOS expression. Taurine significantly decreased iNOS expression in the S. aureus challenged group. Protein microarray demonstrated that 32/40 and 8/40 inflammatory molecules/mediators were increased after E. coli or S. aureus challenge, respectively. The fold changes of most molecules were higher in the E. coli infection group than that in the S. aureus infection group. Taurine negatively regulated the inflammatory profile in both bacterial infections. Pro-inflammatory cytokines (such as TNF-α) connected with TLR activation were down-regulated by taurine pre-treatment. The influence of TAK-242 and OxPAPC on cytokine/molecule expression profiles to E. coli challenge are different than to S. aureus. Some important factors (MyD88, TNF-α, IL-1β, iNOS and IL-6) mediated by TLR activation were suppressed either in protein microarray or special assay (PCR/kits) or both. TAK-242 restrained ROS production and NAGase activity similar to the effect of taurine in E. coli challenge groups. The detection of 3 indices (T-AOC, SOD and MDA) reflecting oxidative stress in vivo, showed that

  7. Staphylococcus aureus and Staphylococcal Food-Borne Disease: An Ongoing Challenge in Public Health

    OpenAIRE

    2014-01-01

    Staphylococcal food-borne disease (SFD) is one of the most common food-borne diseases worldwide resulting from the contamination of food by preformed S. aureus enterotoxins. It is one of the most common causes of reported food-borne diseases in the United States. Although several Staphylococcal enterotoxins (SEs) have been identified, SEA, a highly heat-stable SE, is the most common cause of SFD worldwide. Outbreak investigations have found that improper food handling practices in the retail ...

  8. Staphylococcus aureus and staphylococcal food-borne disease: an ongoing challenge in public health.

    Science.gov (United States)

    Kadariya, Jhalka; Smith, Tara C; Thapaliya, Dipendra

    2014-01-01

    Staphylococcal food-borne disease (SFD) is one of the most common food-borne diseases worldwide resulting from the contamination of food by preformed S. aureus enterotoxins. It is one of the most common causes of reported food-borne diseases in the United States. Although several Staphylococcal enterotoxins (SEs) have been identified, SEA, a highly heat-stable SE, is the most common cause of SFD worldwide. Outbreak investigations have found that improper food handling practices in the retail industry account for the majority of SFD outbreaks. However, several studies have documented prevalence of S. aureus in many food products including raw retail meat indicating that consumers are at potential risk of S. aureus colonization and subsequent infection. Presence of pathogens in food products imposes potential hazard for consumers and causes grave economic loss and loss in human productivity via food-borne disease. Symptoms of SFD include nausea, vomiting, and abdominal cramps with or without diarrhea. Preventive measures include safe food handling and processing practice, maintaining cold chain, adequate cleaning and disinfection of equipment, prevention of cross-contamination in home and kitchen, and prevention of contamination from farm to fork. This paper provides a brief overview of SFD, contributing factors, risk that it imposes to the consumers, current research gaps, and preventive measures.

  9. Prevalence and Trends of Staphylococcus aureus Bacteraemia in Hospitalized Patients in South Africa, 2010 to 2012: Laboratory-Based Surveillance Mapping of Antimicrobial Resistance and Molecular Epidemiology.

    Directory of Open Access Journals (Sweden)

    Olga Perovic

    Full Text Available We aimed to obtain an in-depth understanding on recent antimicrobial resistance trends and molecular epidemiology trends of S. aureus bacteraemia (SAB.Thirteen academic centres in South Africa were included from June 2010 until July 2012. S. aureus susceptibility testing was performed on the MicroScan Walkaway. Real-time PCR using the LightCycler 480 II was done for mecA and nuc. SCCmec and spa-typing were finalized with conventional PCR. We selected one isolate per common spa type per province for multilocus sequence typing (MLST.S. aureus from 2709 patients were included, and 1231 (46% were resistant to methicillin, with a significant decline over the three-year period (p-value = 0.003. Geographical distribution of MRSA was significantly higher in Gauteng compared to the other provinces (P<0.001. Children <5 years were significantly associated with MRSA with higher rates compared to all other age groups (P = 0.01. The most prevalent SCCmec type was SCCmec type III (531 [41%] followed by type IV (402 [31%]. Spa-typing discovered 47 different spa-types. The five (87% most common spa-types were t037, t1257, t045, t064 and t012. Based on MLST, the commonest was ST612 clonal complex (CC8 (n = 7 followed by ST5 (CC5 (n = 4, ST36 (CC30 (n = 4 and ST239 (CC8 (n = 3.MRSA rate is high in South Africa. Majority of the isolates were classified as SCCmec type III (41% and type IV (31%, which are typically associated with hospital and community- acquired infections, respectively. Overall, this study reveals the presence of a variety of hospital-acquired MRSA clones in South Africa dominance of few clones, spa 037 and 1257. Monitoring trends in resistance and molecular typing is recommended to detect changing epidemiological trends in AMR patterns of SAB.

  10. Population structure and characterisation of Staphylococcus aureus from bacteraemia at multiple hospitals in China: association between antimicrobial resistance, toxin genes and genotypes.

    Science.gov (United States)

    He, Wenqiang; Chen, Hongbin; Zhao, Chunjiang; Zhang, Feifei; Li, Henan; Wang, Qi; Wang, Xiaojuan; Wang, Hui

    2013-09-01

    Staphylococcus aureus from bacteraemia at multiple hospitals in China were genetically characterised to improve understanding of its epidemiology. A total of 236 consecutive, non-duplicate S. aureus bacteraemia isolates were collected at 16 Chinese hospitals. Isolates were characterised by antimicrobial resistance, 19 toxin genes, agr alleles, multilocus sequence typing and spa typing. The prevalence of meticillin-resistant S. aureus (MRSA) was 47.5% (112/236). Forty-two sequence types (STs) and 63 spa types were identified, including 14 STs and 14 spa types for MRSA. Clonal complex (CC) 8, CC5, ST7 and CC188 accounted for 67.4% of the isolates. ST239-t030/t037-SCCmecIII-agrI was the predominant MRSA genotype (50%), followed by ST5-t002/t570-SCCmecII-agrII (8%). A vancomycin MIC ≥ 1mg/L was detected significantly more often in ST5-SCCmecII and ST239-t037-SCCmecIII, whereas rifampicin resistance was overwhelmingly associated with ST239-t030-SCCmecIII (Paureus (MSSA) were ST7-t091/t796-agrI (16.1%), ST188-t189-agrI (12.1%) and ST398-t571/t034-agrI (5.6%). Toxin genes were identified in 95.8% of isolates and formed 89 toxin gene profiles. The toxin genes sea, selk, selq and sell were significantly more common in MRSA, whilst tsst-1, seb, sed, selm, seln, selp and selj were more prevalent in MSSA (Ptoxin gene profiles.

  11. Prevalence and Trends of Staphylococcus aureus Bacteraemia in Hospitalized Patients in South Africa, 2010 to 2012: Laboratory-Based Surveillance Mapping of Antimicrobial Resistance and Molecular Epidemiology

    Science.gov (United States)

    Perovic, Olga; Iyaloo, Samantha; Kularatne, Ranmini; Lowman, Warren; Bosman, Noma; Wadula, Jeannette; Seetharam, Sharona; Duse, Adriano; Mbelle, Nontombi; Bamford, Colleen; Dawood, Halima; Mahabeer, Yesholata; Bhola, Prathna; Abrahams, Shareef; Singh-Moodley, Ashika

    2015-01-01

    Introduction We aimed to obtain an in-depth understanding on recent antimicrobial resistance trends and molecular epidemiology trends of S. aureus bacteraemia (SAB). Methods Thirteen academic centres in South Africa were included from June 2010 until July 2012. S. aureus susceptibility testing was performed on the MicroScan Walkaway. Real-time PCR using the LightCycler 480 II was done for mecA and nuc. SCCmec and spa-typing were finalized with conventional PCR. We selected one isolate per common spa type per province for multilocus sequence typing (MLST). Results S. aureus from 2709 patients were included, and 1231 (46%) were resistant to methicillin, with a significant decline over the three-year period (p-value = 0.003). Geographical distribution of MRSA was significantly higher in Gauteng compared to the other provinces (P<0.001). Children <5 years were significantly associated with MRSA with higher rates compared to all other age groups (P = 0.01). The most prevalent SCCmec type was SCCmec type III (531 [41%]) followed by type IV (402 [31%]). Spa-typing discovered 47 different spa-types. The five (87%) most common spa-types were t037, t1257, t045, t064 and t012. Based on MLST, the commonest was ST612 clonal complex (CC8) (n = 7) followed by ST5 (CC5) (n = 4), ST36 (CC30) (n = 4) and ST239 (CC8) (n = 3). Conclusions MRSA rate is high in South Africa. Majority of the isolates were classified as SCCmec type III (41%) and type IV (31%), which are typically associated with hospital and community- acquired infections, respectively. Overall, this study reveals the presence of a variety of hospital-acquired MRSA clones in South Africa dominance of few clones, spa 037 and 1257. Monitoring trends in resistance and molecular typing is recommended to detect changing epidemiological trends in AMR patterns of SAB. PMID:26719975

  12. Staphylococcus aureus in the house fly: temporospatial fate of bacteria and expression of the antimicrobial peptide defensin

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    House flies disseminate numerous species of bacteria acquired during feeding and breeding activities in microbe-rich habitats. Previous house fly surveys have detected the pathogen Staphylococcus aureus, which causes cutaneous and septic infections in mammals and enterotoxic food poisoning. We asses...

  13. Changes in antimicrobial susceptibility patterns of Klebsiella pneumoniae, Escherichia coli and Staphylococcus aureus over the past decade

    DEFF Research Database (Denmark)

    Barfod, Toke Seierøe; Wibroe, Elisabeth Arnberg; Braüner, Julie Vestergaard;

    2015-01-01

    susceptibility at Hvidovre Hospital, Denmark, from 2004 to 2008. Due to a suspected rise in resistance in Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae after this period, updated data for these bacteria are shown for selected antibiotics until 2014. The department receives samples from...

  14. No induction of antimicrobial resistance in Staphylococcus aureus and Listeria monocytogenes during continuous exposure to eugenol and citral.

    Science.gov (United States)

    Apolónio, Joana; Faleiro, Maria L; Miguel, Maria G; Neto, Luís

    2014-05-01

    The aim of this study was to evaluate the adaptation response of Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), and Listeria monocytogenes to the essential oil (EO), eugenol, and citral. The minimum inhibitory concentration of eugenol and citral was determined by agar dilution and microdilution. Adaptation to eugenol and citral was done by sequential exposure of the pathogens to increasing concentrations of the essential oils. The M2-A9 standard was used to determine the antibiotic susceptibility. The effect of eugenol and citral on the adherence ability was evaluated by the crystal violet assay. The impact of adaptation to eugenol on virulence was estimated using the Galleria mellonella model. No development of resistance to the components and antibiotics was observed in the adapted cells of S. aureus, MRSA, and L. monocytogenes. Eugenol and citral at subinhibitory concentration reduced the bacterial adherence. Adaptation to subinhibitory concentration of eugenol affected the virulence potential of S. aureus, MRSA, and L. monocytogenes. Eugenol and citral do not pose a risk of resistance development in a continuous mode of use. These EO components showed a high efficacy as antistaphylococcal and antilisterial biofilm agents. Adaptation at subinhibitory concentration of eugenol protected the larvae against listerial and staphylococcal infection.

  15. In vitro activities of ceftobiprole, tigecycline, daptomycin, and 19 other antimicrobials against methicillin-resistant Staphylococcus aureus strains from a national survey of Belgian hospitals.

    Science.gov (United States)

    Denis, Olivier; Deplano, Ariane; Nonhoff, Claire; Hallin, Marie; De Ryck, Raf; Vanhoof, Raymond; De Mendonça, Ricardo; Struelens, Marc J

    2006-08-01

    The in vitro activities of 22 antimicrobial agents, including ceftobiprole, daptomycin, and tigecycline, against 511 methicillin-resistant Staphylococcus aureus (MRSA) isolates from 112 Belgian hospitals were studied by using the CLSI agar dilution method. Isolates were characterized by pulsed-field gel electrophoresis (PFGE) analysis and by PCR detection of determinants of resistance to aminoglycosides, macrolides-lincosamides-streptogramins, and tetracyclines. A representative set of isolates with different PFGE genotypes was further characterized by multilocus sequence typing, determination of staphylococcal cassette chromosome mec (SCCmec) type, and multiplex PCR for toxic shock syndrome type 1 (TSST-1) and Panton-Valentine leukocidin genes. MRSA isolates belonged to nine epidemic MRSA clones, of which sequence type 45 (ST45)-SCCmec IV and ST8-SCCmec IV were predominant, accounting for 49 and 20% of isolates, respectively. The distribution of antimicrobial resistance and TSST-1 genes was strongly linked to clonal types. Ceftobiprole, daptomycin, and tigecycline showed high activity against all isolates of these sporadic and epidemic MRSA clones, as indicated by MIC(90)s of 2 mg/liter, 0.5 mg/liter, and 0.25 mg/liter, respectively. The MIC distribution of daptomycin and tigecycline was not different in isolates with decreased susceptibility to glycopeptides or tetracyclines, respectively. Ceftobiprole MICs were not correlated with oxacillin and cefoxitin MICs. These data indicate excellent activity of the newly developed agents ceftobiprole, daptomycin, and tigecycline against MRSA isolates recently recovered from hospitalized patients in Belgium, supporting their therapeutic potential for nosocomial MRSA infections.

  16. Atividade antimicrobiana do extrato de Anacardium occidentale Linn. em amostras multiresistentes de Staphylococcus aureus Antimicrobial activity of the hydroalcoholic extract of Anacardium occidentale Linn. against multi-drug resistant strains of Staphylococcus aureus

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    Jackeline G. da Silva

    2007-12-01

    Full Text Available Plantas medicinais com propriedades terapêuticas são de grande relevância em todo o mundo, principalmente em países em desenvolvimento. A planta Anacardium occidentale Linn. é largamente usada na medicina tradicional na nossa região, como antidiarréico, para amigdalite, bronquites, artrites, e antiiflamatório. No presente estudo avaliou-se a ação antimicrobiana do extrato hidroalcóolico da casca do caule do cajueiro frente a amostras de Staphylococcus aureus resistentes e sensíveis à meticilina, obtidas a partir de pacientes internados do Hospital Universitário/Universidade Federal da Paraíba. A atividade antimicrobiana foi determinada pelo método de difusão em meio sólido para a determinação da Concentração Inibitória Mínima do extrato, e foi observada no total de 30 amostras, pela presença ou não do halo de inibição. Todas as amostras ensaiadas mostraram-se sensíveis à ação do extrato do cajueiro, com diâmetros dos halos de inibição variando de 10 a 20 mm, demonstrando grande eficácia do cajueiro. Assim, o uso desta planta na nossa região pode inferir uma alternativa terapêutica eficiente e de baixo custo, contra infecções bacterianas causadas por Staphylococcus aureus.Medicinal plants with therapeutical properties are of great significance in the whole world, especially in developing countries. Anacardium occidentale Linn. is a plant widely used in the traditional medicine in our region against diarrhea, tonsillitis, bronchitis, arthritis, and inflammation. In this paper, the antimicrobial activity of the hydroalcoholic extract of the cashew tree stem was evaluated against samples of meticillin-resistant and meticillin-sensible Staphylococcus aureus, attained from patients interned at Hospital Universitário/Universidade Federal da Paraíba. The antimicrobial activity was determined by the diffusion method in solid milieu to determine the Minimum Inhibitory Concentration (MIC of the extract, and it was

  17. The Chennai declaration: A roadmap to tackle the challenge of antimicrobial resistance

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    A Ghafur

    2013-01-01

    Full Text Available "A Roadmap to Tackle the Challenge of Antimicrobial Resistance - A Joint meeting of Medical Societies in India" was organized as a pre-conference symposium of the 2 nd annual conference of the Clinical Infectious Disease Society (CIDSCON 2012 at Chennai on 24 th August. This was the first ever meeting of medical societies in India on issue of tackling resistance, with a plan to formulate a road map to tackle the global challenge of antimicrobial resistance from the Indian perspective. We had representatives from most medical societies in India, eminent policy makers from both central and state governments, representatives of World Health Organization, National Accreditation Board of Hospitals, Medical Council of India, Drug Controller General of India, and Indian Council of Medical Research along with well-known dignitaries in the Indian medical field. The meeting was attended by a large gathering of health care professionals. The meeting consisted of plenary and interactive discussion sessions designed to seek experience and views from a large range of health care professionals and included six international experts who shared action plans in their respective regions. The intention was to gain a broad consensus and range of opinions to guide formation of the road map. The ethos of the meeting was very much not to look back but rather to look forward and make joint efforts to tackle the menace of antibiotic resistance. The Chennai Declaration will be submitted to all stake holders.

  18. Effects of Silver Nanoparticles on Multiple Drug-Resistant Strains of Staphylococcus aureus and Pseudomonas aeruginosa from Mastitis-Infected Goats: An Alternative Approach for Antimicrobial Therapy

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    Yu-Guo Yuan

    2017-03-01

    Full Text Available Recently, silver nanoparticles (AgNPs have been widely used in various applications as antimicrobial agents, anticancer, diagnostics, biomarkers, cell labels, and drug delivery systems for the treatment of various diseases. Microorganisms generally acquire resistance to antibiotics through the course of antibacterial therapy. Multi-drug resistance (MDR has become a growing problem in the treatment of infectious diseases, and the widespread use of broad-spectrum antibiotics has resulted in the development of antibiotic resistance by numerous human and animal bacterial pathogens. As a result, an increasing number of microorganisms are resistant to multiple antibiotics causing continuing economic losses in dairy farming. Therefore, there is an urgent need for the development of alternative, cost-effective, and efficient antimicrobial agents that overcome antimicrobial resistance. Here, AgNPs synthesized using the bio-molecule quercetin were characterized using various analytical techniques. The synthesized AgNPs were highly spherical in shape and had an average size of 11 nm. We evaluated the efficacy of synthesized AgNPs against two MDR pathogenic bacteria, namely, Pseudomonas aeruginosa and Staphylococcus aureus, which were isolated from milk samples produced by mastitis-infected goats. The minimum inhibitory concentrations (MICs of AgNPs against P. aeruginosa and S. aureus were found to be 1 and 2 μg/mL, respectively. Our findings suggest that AgNPs exert antibacterial effects in a dose- and time-dependent manner. Results from the present study demonstrate that the antibacterial activity of AgNPs is due to the generation of reactive oxygen species (ROS, malondialdehyde (MDA, and leakage of proteins and sugars in bacterial cells. Results of the present study showed that AgNP-treated bacteria had significantly lower lactate dehydrogenase activity (LDH and lower adenosine triphosphate (ATP levels compared to the control. Furthermore, Ag

  19. Technical specifications on the harmonised monitoring and reporting of antimicrobial resistance in methicillin-resistant Staphylococcus aureus in food-producing animals and food

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    European Food Safety Authority

    2012-10-01

    Full Text Available

    In this report, proposals to improve the harmonisation of monitoring of prevalence, genetic diversity and antimicrobial resistance in methicillin-resistant Staphylococcus aureus (MRSAfrom food-producing animals and food derived thereof by the European Union Member States are presented. The primary route of zoonotic transmission of MRSA is considered to be the direct or indirect occupational contact of livestock professionals with colonised animals, while the role of food as a source of human colonisation or infection is presently considered to be low. Sampling recommendations have therefore prioritised several different food-producing animal populations previously described as MRSA reservoirs and, to a lesser extent, food produced by these animals. Monitoring in primary production, including at slaughter, is pivotal because of the main transmission route, while additional monitoring in food may help with the assessment of consumers’ exposure via this route. A consistent monitoring in broiler flocks, fattening pigs and dairy cattle, as well as in veal calves under 1 year of age and fattening turkey flocks, in those countries where production exceeds 10 million tonnes slaughtered/year, is recommended every third year on a rotating basis. It is proposed that breeding poultry flocks and breeding pigs, as well as meat and raw milk products, are monitored on a voluntary basis. Representative sampling should be made within the framework of the national Salmonella control programmes for the poultry populations targeted, at the slaughterhouse for calves and either on farm or at the slaughterhouse for fattening pigs. Harmonised analytical methodologies for identification, typing and further characterisation of MRSA are proposed. The use of the microdilution method applied to a harmonised set of antimicrobials, and interpreted using EUCAST epidemiological cut-off values for antimicrobial susceptibility testing of MRSA, is recommended

  20. Estudos de QSAR-3D em derivados 5-nitro-2-tiofilidênicos com atividade frente a Staphylococcus aureus multi-resistente 3D QSAR studies of 5-nitrothiophene derivatives with antimicrobial activity against multidrug-resistant Staphylococcus aureus

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    Andrea Masunari

    2007-06-01

    Full Text Available Campos moleculares extraídos de aplicativos utilizados em estudos de QSAR-3D apresentam, em geral, grande número de informações, muitas vezes irrelevantes na expressão da atividade biológica. O programa Volsurf converte as informações presentes em mapas de energia de interação tridimensionais em número reduzido de descritores bidimensionais que se caracterizam como de fácil entendimento e interpretação. Assim, foram avaliados, neste estudo, dezoito derivados 5-nitro-2-tiofilidênicos com atividade antimicrobiana frente a Staphylococcus aureus multi-resistente, correlacionando as características tridimensionais destes ligantes com a referida atividade. Para o desenho e conversão tridimensional dos ligantes foram utilizados os aplicativos Sybyl (Tripos Inc e CORINA (Molecular Networks GmbH Computerchemie, respectivamente. Os campos de interação molecular foram calculados no programa GRID (Molecular Discovery Ltd. A aplicação do programa Volsurf (Molecular Discovery Ltd resultou em modelo estatisticamente robusto (r² = 0,93, q² = 0,87 com 48 descritores estruturais, mostrando ser a hidrofobicidade propriedade fundamental no condicionamento da atividade antimicrobiana.Studies in three-dimensional molecular fields generally contain a large amount of data, some of which are redundant or not relevant. The program Volsurf, a quite fast method, is able to compress the relevant information present in 3D molecular structures into a few easy bidimensional descriptors. This study correlates the antimicrobial activity of eighteen 5-nitro-2-thiophylidene derivatives against multidrug-resistant Staphylococcus aureus with three-dimensional molecular fields of these ligands. For molecular structures sketching and 3D conversion, Sybyl and CORINA programs were used, respectively. The GRID force field was applied to generate the 3D interaction energies. The Volsurf characterization results on significant statistic model with 48 descriptors (r

  1. Antimicrobial Susceptibility of Bloodstream Isolates of Staphylococcus aureus: Global Results from the Tigecycline Evaluation and Surveillance Trial, 2004-2008

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    Daniel Amsterdam

    2010-01-01

    Full Text Available Problem statement: The Tigecycline Evaluation and Surveillance Trial (TEST commenced in 2004 to monitor the activity of tigecycline, a new glycylcycline and numerous comparators against major hospital-and community-associated pathogens. In this report we examine the efficacy of tigecycline and comparators against isolates of Staphylococcus aureus collected from blood. Approach: Almost 4000 blood-derived isolates of Staphylococcus aureus were collected from participating centers globally between 2004-2008. Results: All isolates were susceptible to tigecycline (MIC90 0.25 mg L-1 and linezolid (MIC90 4 mg L-1; 99.9% of isolates were susceptible to vancomycin (MIC90 1 mg L-1. Tigecycline and linezolid activity were unaffected by resistance to methicillin, ICU vs non-ICU isolate collection or the age of patients from which the isolates were collected. Although 95.3% of MSSA were levofloxacin susceptible, only 14.4% of MRSA isolates were susceptible to levofloxacin in this study. Conclusion: Tigecycline is shown here to be active against S. aureus isolates collected from blood and is unaffected by methicillin resistance. However, tigecycline is not as yet approved for the treatment of bacteremic infections.

  2. Virulence factors and antimicrobial resistance of Staphylococcus aureus isolated from bovine mastitis in Rio de Janeiro Fatores de virulência e resistência antimicrobiana em Staphylococcus aureus isolados de mastite bovina no Rio de Janeiro

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    Shana M.O. Coelho

    2009-05-01

    Full Text Available The study was conducted to characterize pheno-genotypically the virulence factors and resistance pattern of Staphylococcus aureus isolates from milk samples of cows with subclinical mastitis. All hemolytic isolates presented beta-hemolysin, and 38% of the non-hemolytic isolates were able to express hemolysins in the presence of a beta-hemolytic strain. The amplification of the coa-gene displayed four different size polymorphisms with about 400 bp, 600 bp, 700 bp and 900 bp. The spaA gene that encodes the IgG-binding region of protein A revealed sizes of 700 bp and 900 bp. The amplification of region X from spaA yielded a single amplicon for each isolate with the prevalent amplicon size being of 180 bp. Amplification of sae gene yielded an amplicon size of 920 bp in 71% of the isolates. Antibiotic resistance pattern revealed that 42% S. aureus were susceptible to all antimicrobials tested. Seven different antibiotic patterns were observed. Our results indicated that 47% and 25% of S. aureus strains exhibited resistance to penicillin and oxacillin respectively. All oxacillin-resistant isolates were mecA-positive.O presente estudo foi conduzido com o objetivo de caracterizar feno-genotipicamente os fatores de virulência e perfil de resistência aos antibióticos de Staphylococcus aureus isolados de amostras de leite de vacas com mastite clínica e subclínica. Em todos os isolados hemolíticos foi detectada a presença de beta hemolisina e 38% dos não-hemolíticos produziram hemolisinas na presença de cepa beta-hemolítica. A amplificação do gene coa apresentou quatro tipos polimórficos distintos com aproximadamente 400 bp, 600 bp, 700 bp e 900 bp. O gene spaA que codifica a região de ligação da proteína A à IgG apresentou bandas de 700 bp e 900 bp. A amplificação do gene que codifica a região X revelou um único amplicon para cada isolado sendo o tamanho prevalente o de 250pb. A amplificação do gene sae resultou em amplicons com

  3. Antimicrobial activity of ceftobiprole, a novel anti-methicillin-resistant Staphylococcus aureus cephalosporin, tested against contemporary pathogens: results from the SENTRY Antimicrobial Surveillance Program (2005-2006).

    Science.gov (United States)

    Fritsche, Thomas R; Sader, Helio S; Jones, Ronald N

    2008-05-01

    Ceftobiprole is a 1st-in-class anti-methicillin-resistant Staphylococcus aureus (MRSA) extended-spectrum cephalosporin currently in clinical trials for the treatment of complicated skin and skin structure infections (cSSSIs) and nosocomial pneumonia. This agent is also active against other prominent Gram-positive and Gram-negative pathogens, making it an attractive candidate for broad-spectrum therapy. We evaluated the in vitro potency of ceftobiprole tested against the most commonly occurring bacterial pathogens as part of a global surveillance study for the years 2005 to 2006 (>60 medical centers in North America, Latin America, and Europe). All isolates (40 675) were susceptibility tested using reference broth microdilution methods. Ceftobiprole inhibited 100% and >99% of tested S. aureus and coagulase-negative staphylococci at Ceftobiprole was also broadly active against Streptococcus pneumoniae, beta-hemolytic and viridans group streptococci, inhibiting >98% of isolates at ceftobiprole was generally inactive against Enterococcus faecium, the majority of Enterococcus faecalis strains (95.7%) were inhibited at ceftobiprole and ceftazidime), ceftobiprole and cefepime were superior to ceftazidime against Enterobacter spp. and Citrobacter spp. Against Pseudomonas aeruginosa, ceftobiprole was equal in potency to ceftazidime (MIC50, 2 microg/mL) and 2-fold more potent than cefepime. None of these agents inhibited >45% of Acinetobacter spp. at 8 mug/mL. Ceftobiprole is a new anti-MRSA beta-lactam with recognized activity against the most commonly occurring Enterobacteriaceae and P. aeruginosa, similar to that of extended-spectrum cephems. These characteristics warrant continued evaluation of the agent as empiric therapy for cSSSIs, and in pneumonia, especially in those institutions/regions where MRSA and P. aeruginosa may be prevalent.

  4. Effects of composite antimicrobial peptides in weanling piglets challenged with deoxynivalenol: II. Intestinal morphology and function.

    Science.gov (United States)

    Xiao, H; Tan, B E; Wu, M M; Yin, Y L; Li, T J; Yuan, D X; Li, L

    2013-10-01

    Deoxynivalenol (DON) affects animal and human health and targets the gastrointestinal tract. The objective of this study was to evaluate the ability of composite antimicrobial peptides (CAP) to repair intestinal injury in piglets challenged with DON. A total of 28 piglets (Duroc × Landrace × Large Yorkshire) weaned at 28 d of age were randomly assigned to receive 1 of 4 treatments (7 pigs/treatment): negative control, basal diet (NC), basal diet + 0.4% composite antimicrobial peptide (CAP), basal diet + 4 mg/kg DON (DON), and basal diet + 4 mg/kg DON + 0.4% CAP (DON + CAP). After an adaptation period of 7 d, blood samples were collected on d 15 and 30 after the initiation of treatment for determinations of the concentrations of D-lactate and diamine oxidase. At the end of the study, all piglets were slaughtered to obtain small intestines for the determination of intestinal morphology, epithelial cell proliferation, and protein expression in the mammalian target of rapamycin (mTOR) signaling pathway. The results showed that DON increased serum concentrations of D-lactate and diamine oxidase, and these values in the CAP and DON + CAP treatments were less than those in the NC and DON treatments, respectively (P morphology and promoted intestinal epithelial cell proliferation and protein synthesis, indicating that CAP may repair the intestinal injury induced by DON.

  5. Screening for methicillin-resistant Staphylococcus aureus carriers among individuals exposed and not exposed to the hospital environment and their antimicrobial sensitivity pattern

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    Bhadravathi Virupaksha Renushri

    2014-01-01

    Full Text Available Aims: This study evaluated the influence of exposure to the hospital environment on methicillin-resistant Staphylococcus aureus (MRSA carriage. The antibiograms of the MRSA isolates were examined. Materials and Methods: Nasal, throat, and web-space swabs were collected from 119 nursing students of the age group 18-23 years (exposed group and 100 age-matched pharmacy students (nonexposed group. S. aureus was identified and antibiogram obtained as per Clinical and Laboratory Standards Institute (CLSI guidelines. MRSA was detected by cefoxitin disc diffusion test and by growth on oxacillin screen agar as per CLSI guidelines. The presence of the mecA gene was confirmed by conventional polymerase chain reaction. Results: The MRSA carrier rates were 11.8% and 4% in the exposed and nonexposed groups, respectively. Association of exposure to the hospital environment with MRSA colonization was statistically significant. All MRSA isolates showed sensitivity to netilmicin, linezolid, tetracycline, vancomycin and teicoplanin. Among the exposed group, 71.4% MRSA isolates were resistant to ciprofloxacin, 64.3% to cotrimoxazole, 64.3% to erythromycin, 28.6% to gentamicin and 21.4% to clindamycin. Among the nonexposed group, 75% MRSA isolates were resistant to ciprofloxacin, 25% to cotrimoxazole, 25% to erythromycin, 25% to gentamicin and 25% to clindamycin. Conclusion: Exposure to the hospital environment was found to be a significant risk factor for MRSA carriage. Hospital-acquired MRSA (HA-MRSA isolates showed greater resistance toward antimicrobials compared with community-acquired MRSA (CA-MRSA isolates. This highlights the need for the appropriate institution of pharmacotherapy in cases of HA-MRSA and CA-MRSA infections and control of transmission by carriers.

  6. Combining biofilm matrix measurements with biomass and viability assays in susceptibility assessments of antimicrobials against Staphylococcus aureus biofilms.

    Science.gov (United States)

    Skogman, Malena Elise; Vuorela, Pia Maarit; Fallarero, Adyary

    2012-09-01

    Despite that three types of assays (measuring biofilm viability, biomass, or matrix) are described to assess anti-biofilm activity, they are rarely used together. As infections can easily reappear if the matrix is not affected after antibiotic treatments, our goal was to explore the simultaneous effects of antibiotics on the viability, biomass and matrix of Staphylococcus aureus biofilms (ATCC 25923). Viability and biomass were quantified using resazurin and crystal violet staining sequentially in the same plate, while matrix staining was conducted with a wheat germ agglutinin-Alexa Fluor 488 fluorescent conjugate. Establishment of the detection limits and linearity ranges allowed concluding that all three methods were able to estimate biofilm formation in a similar fashion. In a susceptibility study with 18-h biofilms, two model compounds (penicillin G and ciprofloxacin) caused a reduction on the viability and biomass accompanied by an increase or not changed levels of the matrix, respectively. This response pattern was also proven for S. aureus Newman, S. epidermidis and E. coli biofilms. A classification of antibiotics based on five categories according to their effects on viability and matrix has been proposed earlier. Our data suggests a sixth group, represented by penicillin, causing decrease in bacterial viability but showing stimulatory effects on the matrix. Further, if effects on the matrix are not taken into account, the long-term chemotherapeutic effect of antibiotics can be jeopardized in spite of the positive effects on biofilms viability and biomass. Thus, measuring all these three endpoints simultaneously provide a more complete and accurate picture.

  7. The TIR Homologue Lies near Resistance Genes in Staphylococcus aureus, Coupling Modulation of Virulence and Antimicrobial Susceptibility

    Science.gov (United States)

    Patot, Sabine; RC Imbert, Paul; Baude, Jessica; Martins Simões, Patricia; Campergue, Jean-Baptiste; Louche, Arthur; Bès, Michèle; Tristan, Anne; Laurent, Frédéric; Fischer, Adrien; Schrenzel, Jacques; François, Patrice; Lina, Gérard

    2017-01-01

    Toll/interleukin-1 receptor (TIR) domains in Toll-like receptors are essential for initiating and propagating the eukaryotic innate immune signaling cascade. Here, we investigate TirS, a Staphylococcus aureus TIR mimic that is part of a novel bacterial invasion mechanism. Its ectopic expression in eukaryotic cells inhibited TLR signaling, downregulating the NF-kB pathway through inhibition of TLR2, TLR4, TLR5, and TLR9. Skin lesions induced by the S. aureus knockout tirS mutant increased in a mouse model compared with wild-type and restored strains even though the tirS-mutant and wild-type strains did not differ in bacterial load. TirS also was associated with lower neutrophil and macrophage activity, confirming a central role in virulence attenuation through local inflammatory responses. TirS invariably localizes within the staphylococcal chromosomal cassettes (SCC) containing the fusC gene for fusidic acid resistance but not always carrying the mecA gene. Of note, sub-inhibitory concentration of fusidic acid increased tirS expression. Epidemiological studies identified no link between this effector and clinical presentation but showed a selective advantage with a SCCmec element with SCC fusC/tirS. Thus, two key traits determining the success and spread of bacterial infections are linked. PMID:28060920

  8. Challenges of implementing national guidelines for the control and prevention of methicillin-resistant Staphylococcus aureus colonization or infection in acute care hospitals in the Republic of Ireland.

    LENUS (Irish Health Repository)

    Fitzpatrick, Fidelma

    2009-03-01

    Of the 49 acute care hospitals in Ireland that responded to the survey questionnaire drafted by the Infection Control Subcommittee of the Health Protection Surveillance Centre\\'s Strategy for the Control of Antimicrobial Resistance in Ireland, 43 reported barriers to the full implementation of national guidelines for the control and prevention of methicillin-resistant Staphylococcus aureus infection; these barriers included poor infrastructure (42 hospitals), inadequate laboratory resources (40 hospitals), inadequate staffing (39 hospitals), and inadequate numbers of isolation rooms and beds (40 hospitals). Four of the hospitals did not have an educational program on hand hygiene, and only 17 had an antibiotic stewardship program.

  9. Proteome-wide antigen discovery of novel protective vaccine candidates against Staphylococcus aureus infection

    DEFF Research Database (Denmark)

    Rasmussen, Karina Juhl; Mattsson, Andreas Holm; Pilely, Katrine;

    2016-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a rapidly growing problem, especially in hospitals where MRSA cause increased morbidity and mortality and a significant rise in health expenditures. As many strains of MRSA are resistant to other antimicrobials in addition to methicillin......-five different S. aureus proteins were identified, recombinantly expressed, and tested for protection in a lethal sepsis mouse model using S. aureus strain MRSA252 as the challenge organism. We found that 13 of the 35 recombinant peptides yielded significant protection and that 12 of these antigens were highly...

  10. Inactivation of Staphylococcus aureus in Oat and Soya Drinks by Enterocin AS-48 in Combination with Other Antimicrobials.

    Science.gov (United States)

    Burgos, María José Grande; Aguayo, M Carmen López; Pulido, Rubén Pérez; Gálvez, Antonio; López, Rosario Lucas

    2015-09-01

    The presence of toxicogenic Staphylococcus aureus in foods and the dissemination of methicillin-resistant S. aureus (MRSA) in the food chain are matters of concern. In the present study, the circular bacteriocin enterocin AS-48, applied singly or in combination with phenolic compounds (carvacrol, eugenol, geraniol, and citral) or with 2-nitro-1-propanol (2NPOH), was investigated in the control of a cocktail made from 1 methicillin-sensitive and 1 MRSA strains inoculated on commercial oat and soya drinks. Enterocin AS-48 exhibited low bactericidal activity against staphylococci in the drinks investigated when applied singly. The combinations of sub-inhibitory concentrations of enterocin AS-48 (25 μg/mL) and phenolic compounds or 2NPOH caused complete inactivation of staphylococci in the drinks within 24 h of incubation at 22 °C. When tested in oat and soya drinks stored for 7 d at 10 °C, enterocin AS-48 (25 μg/mL) in combination with 2NPOH (5.5 mM) reduced viable counts rapidly in the case of oat drink (4.2 log cycles after 12 h) or slowly in soya drink (3.8 log cycles after 3 d). The same combined treatment applied on drinks stored at 22 °C achieved a fast inactivation of staphylococci within 12 to 24 h in both drinks, and no viable staphylococci were detected for up to 7 d of storage. Results from the study highlight the potential of enterocin AS-48 in combination with 2NPOH for inactivation of staphylococci.

  11. Carrier-free nanoassemblies of a novel oxazolidinone compound FYL-67 display antimicrobial activity on methicillin-resistant Staphylococcus aureus

    Science.gov (United States)

    Gong, Changyang; Yang, Tao; Yang, Xiaoyan; Liu, Yuanyuan; Ang, Wei; Tang, Jianying; Pi, Weiyi; Xiong, Li; Chang, Ying; Ye, Weiwei; Wang, Zhenling; Luo, Youfu; Zhao, Xia; Wei, Yuquan

    2012-12-01

    In this work, a novel oxazolidinone compound FYL-67 was synthesized, and the obtained FYL-67 could form nanoassemblies in aqueous solution by a self-assembly method without using any carrier, organic solvent, or surfactant. The prepared FYL-67 nanoassemblies had a particle size of 264.6 +/- 4.3 nm. The FYL-67 nanoassemblies can be lyophilized into a powder form without any cryoprotector or excipient, and the re-dissolved FYL-67 nanoassemblies are stable and homogeneous. The in vitro release profile showed a significant difference between rapid release of free FYL-67 and much slower and sustained release of FYL-67 nanoassemblies. In vitro susceptibility tests were conducted in three strains of methicillin-susceptible Staphylococcus aureus (MSSA) and three strains of methicillin-resistant Staphylococcus aureus (MRSA), using linezolid as a positive control. FYL-67 nanoassemblies exhibited excellent in vitro activity, with a minimum inhibitory concentration (MIC) value of 0.5 μg mL-1 against MRSA. In the in vitro post-antibiotic effect (PAE) evaluation, FYL-67 nanoassemblies showed a more powerful effect than linezolid. Besides, in vitro cytotoxicity tests indicated that FYL-67 nanoassemblies had a very low cytotoxicity on HEK293 cells and L02 cells. Furthermore, in both MSSA and MRSA systemic infection mouse models, FYL-67 nanoassemblies showed a lower ED50 than linezolid. In a murine model of MRSA systemic infection, FYL-67 nanoassemblies displayed an ED50 of less than 4.0 mg kg-1, which is 2.3-fold better than that of linezolid. Our findings suggested that the FYL-67 nanoassemblies may be a potential drug candidate in MRSA therapy.

  12. Potential novel therapeutic strategies in cystic fibrosis: antimicrobial and anti-biofilm activity of natural and designed α-helical peptides against Staphylococcus aureus, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia

    Directory of Open Access Journals (Sweden)

    Pompilio Arianna

    2012-07-01

    Full Text Available Abstract Background Treatment of cystic fibrosis-associated lung infections is hampered by the presence of multi-drug resistant pathogens, many of which are also strong biofilm producers. Antimicrobial peptides, essential components of innate immunity in humans and animals, exhibit relevant in vitro antimicrobial activity although they tend not to select for resistant strains. Results Three α-helical antimicrobial peptides, BMAP-27 and BMAP-28 of bovine origin, and the artificial P19(9/B peptide were tested, comparatively to Tobramycin, for their in vitro antibacterial and anti-biofilm activity against 15 Staphylococcus aureus, 25 Pseudomonas aeruginosa, and 27 Stenotrophomonas maltophilia strains from cystic fibrosis patients. All assays were carried out in physical-chemical experimental conditions simulating a cystic fibrosis lung. All peptides showed a potent and rapid bactericidal activity against most P. aeruginosa, S. maltophilia and S. aureus strains tested, at levels generally higher than those exhibited by Tobramycin and significantly reduced biofilm formation of all the bacterial species tested, although less effectively than Tobramycin did. On the contrary, the viability-reducing activity of antimicrobial peptides against preformed P. aeruginosa biofilms was comparable to and, in some cases, higher than that showed by Tobramycin. Conclusions The activity shown by α-helical peptides against planktonic and biofilm cells makes them promising “lead compounds” for future development of novel drugs for therapeutic treatment of cystic fibrosis lung disease.

  13. 抗菌肽对金黄色葡萄球菌抑制作用的研究%Study on the inhibitory effect of antimicrobial peptides-thanatin against staphylococcus aureus

    Institute of Scientific and Technical Information of China (English)

    刘付弟

    2011-01-01

    Objective To explore the inhibitory effect of antimicrobial peptide s-Thanatin against Staphylococcus aureus by broth microdilution. Methods The activity of s - Thanatin against Staphylococcus aureus was evaluated by the minimum inhibitory concentration (MIC). Results The results demonstrated that the MIC of s- Thanatin against Staphylococcus aureus was 50 mg/L. Conclusion A higher concentration of s- thanatin is necessary to inhibit common pathogenic Staphylococcus aureus. Therefore, the chemical structure of antibacterial peptide Thanatin should be modified to improve the activity against Staphylococcus aureus.%目的 探讨抗菌肽S-Thanatin对金黄色葡萄球菌的抑制效果.方法 采用肉汤微量稀释法研究抗菌肽S-Thanatin对金黄色葡萄球菌的最低抑菌浓度(MIC).结果 抗菌肽S-Thanatin对金黄色葡萄球菌MIC是50 mg/L.结论 抗菌肽S-Thanatin对临床常见的金黄色葡萄球菌需要较高浓度才有抑制作用,因此为进一步提高其抗金黄色葡萄球菌活性,需要对抗菌肽S-Thanatin的化学结构进行改进.

  14. Bacteriostatic antimicrobial combination: antagonistic interaction between epsilon-viniferin and vancomycin against methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Basri, Dayang Fredalina; Xian, Lee Wee; Abdul Shukor, Nur Indah; Latip, Jalifah

    2014-01-01

    Stilbenoids have been considered as an alternative phytotherapeutic treatment against methicillin-resistant Staphylococcus aureus (MRSA) infection. The combined effect of ε-viniferin and johorenol A with the standard antibiotics, vancomycin and linezolid, was assessed against MRSA ATCC 33591 and HUKM clinical isolate. The minimum inhibitory concentration (MIC) value of the individual tested compounds and the fractional inhibitory concentration index (FICI) value of the combined agents were, respectively, determined using microbroth dilution test and microdilution checkerboard (MDC) method. Only synergistic outcome from checkerboard test will be substantiated for its rate of bacterial killing using time-kill assay. The MIC value of ε -viniferin against ATCC 33591 and johorenol A against both strains was 0.05 mg/mL whereas HUKM strain was susceptible to 0.1 mg/mL of ε-viniferin. MDC study showed that only combination between ε-viniferin and vancomycin was synergistic against ATCC 33591 (FICI 0.25) and HUKM (FICI 0.19). All the other combinations (ε-viniferin-linezolid, johorenol A-vancomycin, and johorenol A-linezolid) were either indifferent or additive against both strains. However, despite the FICI value showing synergistic effect for ε-viniferin-vancomycin, TKA analysis displayed antagonistic interaction with bacteriostatic action against both strains. As conclusion, ε-viniferin can be considered as a bacteriostatic stilbenoid as it antagonized the bactericidal activity of vancomycin. These findings therefore disputed previous report that ε-viniferin acted in synergism with vancomycin but revealed that it targets similar site in close proximity to vancomycin's action, possibly at the bacterial membrane protein. Hence, this combination has a huge potential to be further studied and developed as an alternative treatment in combating MRSA in future.

  15. Staphylococcus aureus: methicillin-susceptible S. aureus to methicillin-resistant S. aureus and vancomycin-resistant S. aureus.

    Science.gov (United States)

    Rehm, Susan J; Tice, Alan

    2010-09-15

    The evolution of methicillin-resistant and vancomycin-resistant Staphylococcus aureus has demanded serious review of antimicrobial use and development of new agents and revised approaches to prevent and overcome drug resistance. Depending on local conditions and patient risk factors, empirical therapy of suspected S. aureus infection may require coverage of drug-resistant organisms with newer agents and novel antibiotic combinations. The question of treatment with inappropriate antibiotics raises grave concerns with regard to methicillin-resistant S. aureus selection, overgrowth, and increased virulence. Several strategies to reduce the nosocomial burden of resistance are suggested, including shortened hospital stays and outpatient parenteral antimicrobial therapy of the most serious infections.

  16. La(III) complex involving the O,N-donor environment of quinazoline-4(3H)-one Schiff’s base and their antimicrobial attributes against methicillin-resistant Staphylococcus aureus (MRSA)

    Science.gov (United States)

    Siddappa, K.; Mane, Sunilkumar B.; Manikprabhu, Deene

    2014-09-01

    The incidence of methicillin-resistant Staphylococcus aureus increased during the past few decades, so there is an urgent need of new antimicrobial agents if public health is concerned. Though the Schiff’s bases and La(III) complex have enormous biological activity, but less attention was given in their synthesis. In the present investigation, we synthesized a new (E)-3-((2-hydroxynaphthalen-1-yl) methyleneamino)-2-methylquinazoline-4(3H)-one HNMAMQ Schiff’s base by the condensation of 3-(2-aminophenyl) quinazolin-2-methyl-4(3H)-one and 2-hydroxy-1-naphthaldehyde. The Schiff’s base HNMAMQ and its La(III) complex were characterized by elemental analyses, IR, NMR, mass spectra, and thermal studies. The newly synthesized Schiff’s base HNMAMQ and its La(III) complex were evaluated for their antimicrobial activity against methicillin-resistant Staphylococcus aureus isolated from the Gulbarga region in India. The Schiff’s base HNMAMQ and its La(III) complex showed good antimicrobial activity and thus represents a potential new drug of choice.

  17. Antimicrobial activity of ceftaroline against methicillin-resistant Staphylococcus aureus (MRSA) isolates collected in 2013-2014 at the Geneva University Hospitals.

    Science.gov (United States)

    Andrey, D O; François, P; Manzano, C; Bonetti, E J; Harbarth, S; Schrenzel, J; Kelley, W L; Renzoni, A

    2017-02-01

    Ceftaroline is a broad-spectrum antibiotic with activity against methicillin-resistant Staphylococcus aureus (MRSA) strains. Ceftaroline susceptibility of an MRSA set archived between 1994 and 2003 in the Geneva University Hospitals detected a high percentage (66 %) of ceftaroline resistance in clonotypes ST228 and ST247 and correlated with mutations in PBP2a. The ceftaroline mechanism of action is based on the inhibition of PBP2a; thus, the identification of PBP2a mutations of recently circulating clonotypes in our institution was investigated. We analyzed ceftaroline susceptibility in MRSA isolates (2013 and 2014) and established that resistant strains correlated with PBP2a mutations and specific clonotypes. Ninety-six MRSA strains were analyzed from independent patients and were isolated from blood cultures (23 %), deep infections (38.5 %), and superficial (skin or wound) infections (38.5 %). This sample showed a ceftaroline minimum inhibitory concentration (MIC) range between 0.25 and 2 μg/ml and disk diameters ranging from 10 to 30 mm, with a majority of strains showing diameters ≥20 mm. Based on the European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints, 76 % (73/96) of isolates showed susceptibility to ceftaroline. Nevertheless, we still observed 24 % (23/96) of resistant isolates (MIC = 2 μg/ml). All resistant isolates were assigned to clonotype ST228 and carried the N146K mutation in PBP2a. Only two ST228 isolates showed ceftaroline susceptibility. The decreasing percentage of ceftaroline-resistant isolates in our hospital can be explained by the decline of ST228 clonotype circulating in our hospital since 2008. We present evidence that ceftaroline is active against recent MRSA strains from our hospital; however, the presence of PBP2a variants in particular clonotypes may affect ceftaroline efficacy.

  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.

    Science.gov (United States)

    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. Mechanisms of Antimicrobial Resistance in ESKAPE Pathogens

    Directory of Open Access Journals (Sweden)

    Sirijan Santajit

    2016-01-01

    Full Text Available The ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species are the leading cause of nosocomial infections throughout the world. Most of them are multidrug resistant isolates, which is one of the greatest challenges in clinical practice. Multidrug resistance is amongst the top three threats to global public health and is usually caused by excessive drug usage or prescription, inappropriate use of antimicrobials, and substandard pharmaceuticals. Understanding the resistance mechanisms of these bacteria is crucial for the development of novel antimicrobial agents or other alternative tools to combat these public health challenges. Greater mechanistic understanding would also aid in the prediction of underlying or even unknown mechanisms of resistance, which could be applied to other emerging multidrug resistant pathogens. In this review, we summarize the known antimicrobial resistance mechanisms of ESKAPE pathogens.

  20. International Study Group on New Antimicrobial Strategies (ISGNAS) : Meeting the challenge of resistance to antibiotics

    NARCIS (Netherlands)

    van der Waaij, D; Heidt, PJ; Rusch,; VanderWaaij, D

    1997-01-01

    ISGNAS enables advancement of research through building a network of organisations and is also working to develop new antimicrobial strategies. Communication among participants is accomplished through published reports, E-mail, Internet, symposia, and special announcements.

  1. Antimicrobial activity of Gymnema sylvestre leaf extract.

    Science.gov (United States)

    Satdive, R K; Abhilash, P; Fulzele, Devanand P

    2003-12-01

    The ethanolic extract of Gymnema sylvestre leaves demonstrated antimicrobial activity against Bacillus pumilis, B. subtilis, Pseudomonas aeruginosa and Staphylococcus aureus and inactivity against Proteus vulgaris and Escherichia coli.

  2. MRI Based Localisation and Quantification of Abscesses following Experimental S. aureus Intravenous Challenge: Application to Vaccine Evaluation.

    Directory of Open Access Journals (Sweden)

    Elizabeth R Allen

    Full Text Available To develop and validate a sensitive and specific method of abscess enumeration and quantification in a preclinical model of Staphylococcus aureus infection.S. aureus infected murine kidneys were fixed in paraformaldehyde, impregnated with gadolinium, and embedded in agar blocks, which were subjected to 3D magnetic resonance microscopy on a 9.4T MRI scanner. Image analysis techniques were developed, which could identify and quantify abscesses. The result of this imaging was compared with histological examination. The impact of a S. aureus Sortase A vaccination regime was assessed using the technique.Up to 32 murine kidneys could be imaged in a single MRI run, yielding images with voxels of about 25 μm3. S. aureus abscesses could be readily identified in blinded analyses of the kidneys after 3 days of infection, with low inter-observer variability. Comparison with histological sections shows a striking correlation between the two techniques: all presumptive abscesses identified by MRI were confirmed histologically, and histology identified no abscesses not evident on MRI. In view of this, simulations were performed assuming that both MRI reconstruction, and histology examining all sections of the tissue, were fully sensitive and specific at abscess detection. This simulation showed that MRI provided more sensitive and precise estimates of abscess numbers and volume than histology, unless at least 5 histological sections are taken through the long axis of the kidney. We used the MRI technique described to investigate the impact of a S. aureus Sortase A vaccine.Post mortem MRI scanning of large batches of fixed organs has application in the preclinical assessment of S. aureus vaccines.

  3. Clonal types and antimicrobial resistance profiles of methicillin-resistant Staphylococcus aureus isolates from hospitals in south Brazil Tipos de clones e perfis de resistência antimicrobiana de Staphylococcus aureus resistentes à meticilina isolados de hospitais no sul do Brasil

    Directory of Open Access Journals (Sweden)

    Leandro Reus Rodrigues Perez

    2008-06-01

    Full Text Available In the present study were evaluated the DNA macrorestriction profile and SCCmec types for nine multi-resistant MRSA selected. Also antimicrobial susceptibility testing by disk diffusion method was evaluated for 68 MRSA isolates against 12 antimicrobial agents. The isolates were recovered from blood culture collected from hospitalized patients in three hospitals of Porto Alegre, Brazil. PFGE and PCR for mecA and SCCmec I, II, III, IV types genes were done on selected nine isolates with susceptibility only to vancomycin, teicoplanin and linezolid. Two clone profiles, with five subtypes, were demonstrated among multi-resistant MRSA analyzed. Eight isolates showed harbor SCCmec type III and one isolate was not typeable. The knowledge of SCCmec type, clone and antimicrobial profiles among S. aureus is essential mainly to prevention and control of dissemination of the antimicrobial resistance.No presente estudo foram avaliados o perfil de macrorrestrição do DNA e tipos de SCCmec para nove MRSA multirresistentes selecionados. Além disso, susceptibilidade a 12 agentes antimicrobianos pelo teste de disco-difusão foi avaliada para 68 isolados de MRSA. Os isolados foram obtidos de hemoculturas de pacientes hospitalizados de três hospitais de Porto Alegre, Brasil. PFGE e PCR para detecção do gene mecA e para os tipos genéticos SCCmec I, II, III e IV foram realizados em nove isolados selecionados que apresentaram susceptibilidade somente a vancomicina, teicoplanina e linezolida. Dois perfis clonais, com cinco subtipos, foram demonstrados entre os isolados analisados. Oito isolados apresentaram SCCmec tipo III e um isolado não foi caracterizado quanto ao tipo de SCCmec. O conhecimento do tipo de SCCmec bem como dos perfis clonais e de susceptibilidade aos antimicrobianos entre isolados de S. aureus é essencial, principalmente, para a prevenção e controle da disseminação da resistência antimicrobiana.

  4. Status of vaccine research and development of vaccines for Staphylococcus aureus.

    Science.gov (United States)

    Giersing, Birgitte K; Dastgheyb, Sana S; Modjarrad, Kayvon; Moorthy, Vasee

    2016-06-03

    Staphylococcus aureus is a highly versatile gram positive bacterium that is resident as an asymptomatic colonizer on the skin and in the nasopharynx of approximately 30% of individuals. Nasopharyngeal colonization is a risk for acquiring S. aureus infections, which can cause a range of clinical symptoms that are commonly associated with skin and soft-tissue infections. The emergence of S. aureus strains that are highly resistant to antimicrobials has recently become a major public health concern. In low-income countries the incidence of S. aureus disease is highest in neonates and children up to one year of age and mortality rates are estimated to be up to 50%. In the United States, S. aureus infection accounts for approximately 300,000 hospitalizations per year. A vaccine against multi-drug resistant S. aureus, therefore, is urgently needed. Two vaccine candidates have previously been evaluated in late-stage clinical trials but have not demonstrated efficacy. At present, one vaccine candidate and two monoclonal antibody are undergoing clinical evaluation in target groups at high risk for S. aureus infection. This review provides an overview of current vaccine development efforts and presents the major technical and regulatory challenges to developing a licensed S. aureus vaccine.

  5. Amphibian antimicrobial peptide fallaxin analogue FL9 affects virulence gene expression and DNA replication in Staphylococcus aureus

    DEFF Research Database (Denmark)

    Gottschalk, Sanne; Gottlieb, Caroline Trebbien; Vestergaard, Martin;

    2015-01-01

    The rapid rise in antibiotic-resistant pathogens is causing increased health concerns, and consequently there is an urgent need for novel antimicrobial agents. Antimicrobial peptides (AMPs), which have been isolated from a wide range of organisms, represent a very promising class of novel antimic...

  6. Antimicrobial resistance profile of Staphylococcus aureus isolates obtained from skin and soft tissue infections of outpatients from a university hospital in Recife - PE, Brazil*

    Science.gov (United States)

    Caraciolo, Fabiana Beserra; Maciel, Maria Amélia Vieira; dos Santos, Josemir Belo; Rabelo, Marcelle Aquino; Magalhães, Vera

    2012-01-01

    BACKGROUND Staphylococcus aureus has a notable ability to acquire resistance to antibiotics, and methicillin resistance represents a growing public health problem. Methicillin-resistant S. aureus (MRSA) has also become important outside the hospital environment, particularly in the United States. In Brazil, since 2005, cases of community skin infections caused by MRSA have been reported, but resistance studies involving outpatients are scarce. OBJECTIVE To know the resistance profile of S. aureus involved in skin and soft tissue infections of patients seen at the Dermatology outpatient clinic of a university hospital in Recife, Pernambuco State, northeastern Brazil. METHODS Prospective study involving 30 patients with skin and soft tissue infections, seen at the Dermatology outpatient clinic from May until November 2011. To evaluate the susceptibility of S. aureus to antibiotics, the disk diffusion method and oxacillin screening agar were used. RESULTS From a total of 30 samples of skin lesions, 19 (63%) had positive culture for S. aureus. The following resistance patterns of S. aureus were observed: penicillin, 95%; tetracycline, 32%; erythromycin, 21%; gentamicin, 16%; cefoxitin, 11%; oxacillin, 11%; trimethoprim-sulfamethoxazole, 11%; chloramphenicol, 11%; clindamycin, 5% ; and ciprofloxacin, 0%. One of the identified MRSA was obtained from a patient without risk factors for its acquisition, and was resistant, beyond to the beta-lactams, only to tetracycline. CONCLUSIONS With regard to the resistance patterns of S. aureus, resistances to tetracycline, erythromycin and gentamicin were the highest. It was documented, for the first time in Pernambuco, a case of skin infection caused by community-associated MRSA. PMID:23197204

  7. Tea tree oil-induced transcriptional alterations in Staphylococcus aureus.

    Science.gov (United States)

    Cuaron, Jesus A; Dulal, Santosh; Song, Yang; Singh, Atul K; Montelongo, Cesar E; Yu, Wanqin; Nagarajan, Vijayaraj; Jayaswal, Radheshyam K; Wilkinson, Brian J; Gustafson, John E

    2013-03-01

    Tea tree oil (TTO) is a steam distillate of Melaleuca alternifolia that demonstrates broad-spectrum antibacterial activity. This study was designed to document how TTO challenge influences the Staphylococcus aureus transcriptome. Overall, bioinformatic analyses (S. aureus microarray meta-database) revealed that both ethanol and TTO induce related transcriptional alterations. TTO challenge led to the down-regulation of genes involved with energy-intensive transcription and translation, and altered the regulation of genes involved with heat shock (e.g. clpC, clpL, ctsR, dnaK, groES, groEL, grpE and hrcA) and cell wall metabolism (e.g. cwrA, isaA, sle1, vraSR and vraX). Inactivation of the heat shock gene dnaK or vraSR which encodes a two-component regulatory system that responds to peptidoglycan biosynthesis inhibition led to an increase in TTO susceptibility which demonstrates a protective role for these genes in the S. aureus TTO response. A gene (mmpL) encoding a putative resistance, nodulation and cell division efflux pump was also highly induced by TTO. The principal antimicrobial TTO terpene, terpinen-4-ol, altered ten genes in a transcriptional direction analogous to TTO. Collectively, this study provides additional insight into the response of a bacterial pathogen to the antimicrobial terpene mixture TTO.

  8. Staphylococcus aureus: incidência e resistência antimicrobiana em abscessos cutâneos de origem comunitária Staphylococcus aureus: etiology and susceptibility profile to antimicrobial agents of skin and subcutaneous cell tissue abscesses from community infections

    Directory of Open Access Journals (Sweden)

    Martin Zavadinack Netto

    2002-03-01

    profilaxia ou tratamento de infecções por S.aureus, mesmo aqueles de origem comunitária.An analysis of Staphylococcus aureus (Monera, an etiological agent of community infections, is provided. Staphylococcus aureus causes the formation of skin and subcutaneous cell tissue abscesses. Susceptibility profile to antimicrobials used in prophylaxis or therapy of these cutaneous infections will be given. One hundred and seven samples of secretions were collected from January 1996 through July 1997 at the emergency sector of University Hospital of the State University of Maringá, Maringá, state of Paraná, Brazil, from infected patients with skin and subcutaneous cell tissue abscesses. Microbiological evaluation was carried out according to Bayle and susceptibility to antimicrobial was evaluated in vitro through the technique of diffusion in agar according to Kirby. Sixteen antimicrobials used in prophylaxis or therapy of skin and subcutaneous cell tissue infections were evaluated. From the one hundred and seven clinical samples collected from patients complaining of infections with skin and subcutaneous cell tissue abscesses, 71 (66.35% were positive to S.aureus and 36 (33,65% were either positive for other microorganisms, or tested negative. In the evaluation of susceptibility to S.aureus a higher sensitivity to vancomycin (100%, teicoplanin (100%, amikacin (100%, cefoxitin (100%, cephalothin (98.53%, lincomycin (98.53%, gentamicin (98.53%, oxacillin (96,4%, norfloxacin (95.77% and sulfazotrin (95.77% was found when compared to penicillin G (08.45%, ampicillin (08.45%, kanamycin (81,69%, erythromycin (88.41%, tetracycline (90.14 and chloramphenicol (94,36%. Results show that S.aureus is the most frequently isolated microorganism from community infections with skin and subcutaneous tissue abscesses. The susceptibility profile evidences high resistance to penicillins, which restricts the use of these antimicrobials as an alternative in the prophylaxis or treatment of S.aureus

  9. Chemical composition and antimicrobial effects of essential oils of Eucalyptus globulus, Myrtus communis and Satureja hortensis against Escherichia coli O157:H7 and Staphylococcus aureus in minced beef.

    Science.gov (United States)

    Djenane, D; Yangüela, J; Amrouche, T; Boubrit, S; Boussad, N; Roncalés, P

    2011-12-01

    Essential oils (EOs) extracted by hydrodistillation from leaf parts of Algerian Eucalyptus globulus, Myrtus communis and Satureja hortensis were analyzed by gas chromatography/mass spectrometry (GC/MS). The main components of EOs obtained were γ-terpinene (94.48%), 1,8-cineole (46.98%) and carvacrol (46.10%), respectively, for E. globulus, M. communis and S. hortensis. The in vitro antimicrobial activity of the EOs was evaluated against Staphylococcus aureus CECT 4459 and Escherichia coli O157:H7 CECT 4267 using the agar diffusion technique. Results revealed that E. globulus and S. hortensis EOs had more antibacterial effects than that from M. communis. Minimal inhibitory concentrations (MIC) showed a range of 0.05-0.22% (volume by volume [v/v]). Sensitivity of gram-positive S. aureus was much higher than that of gram-negative E. coli. Plant EOs were added to minced beef (two-fold MIC value) at 0.10-0.44%, experimentally inoculated with the same pathogens at a level of 5 × 10(5) colony forming units (cfu)/g and stored at 5 ± 2 °C. Results showed that the EOs of E. globulus and S. hortensis had remarkable antibacterial properties, higher than that of M. communis, against S. aureus and E. coli. Indeed, a reduction of 5.8 log cfu/g (70.74% of reduction) was recorded after 7 days of storage for S. hortensis against E. coli. However, regarding S. aureus, both S. hortensis and E. globulus caused a highly significant (p < 0.05) decrease of microbial counts, most evident after 5 days of storage; S. aureus numbers were 3.50 and 2.50 cfu/g, respectively, corresponding to a reduction of 2.20 and 3.20 log cfu/g (38.60 and 56.14% of reduction) after 1 week of storage. Sensory evaluation revealed that the aroma of minced beef meat treated with EOs was acceptable by panelists at the levels used.

  10. Changing epidemiology of methicillin-resistant Staphylococcus aureus in Iceland from 2000 to 2008: a challenge to current guidelines

    DEFF Research Database (Denmark)

    Holzknecht, B.J.; Hardardottir, H.; Haraldsson, Gustav Helgi;

    2010-01-01

    and microbiological data of all MRSA patients from the years 2000 to 2008 were collected prospectively. Isolates were characterized by pulsed-field gel electrophoresis (PFGE), sequencing of the repeat region of the Staphylococcus protein A gene (spa typing), staphylococcal cassette chromosome mec (SCCmec) typing......The epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) is continuously changing. Iceland has a low incidence of MRSA. A "search and destroy" policy (screening patients with defined risk factors and attempting eradication in carriers) has been implemented since 1991. Clinical...

  11. The health and economic burden of bloodstream infections caused by antimicrobial-susceptible and non-susceptible Enterobacteriaceae and Staphylococcus aureus in European hospitals, 2010 and 2011: a multicentre retrospective cohort study.

    Science.gov (United States)

    Stewardson, Andrew J; Allignol, Arthur; Beyersmann, Jan; Graves, Nicholas; Schumacher, Martin; Meyer, Rodolphe; Tacconelli, Evelina; De Angelis, Giulia; Farina, Claudio; Pezzoli, Fabio; Bertrand, Xavier; Gbaguidi-Haore, Houssein; Edgeworth, Jonathan; Tosas, Olga; Martinez, Jose A; Ayala-Blanco, M Pilar; Pan, Angelo; Zoncada, Alessia; Marwick, Charis A; Nathwani, Dilip; Seifert, Harald; Hos, Nina; Hagel, Stefan; Pletz, Mathias; Harbarth, Stephan

    2016-08-18

    We performed a multicentre retrospective cohort study including 606,649 acute inpatient episodes at 10 European hospitals in 2010 and 2011 to estimate the impact of antimicrobial resistance on hospital mortality, excess length of stay (LOS) and cost. Bloodstream infections (BSI) caused by third-generation cephalosporin-resistant Enterobacteriaceae (3GCRE), meticillin-susceptible (MSSA) and -resistant Staphylococcus aureus (MRSA) increased the daily risk of hospital death (adjusted hazard ratio (HR) = 1.80; 95% confidence interval (CI): 1.34-2.42, HR = 1.81; 95% CI: 1.49-2.20 and HR = 2.42; 95% CI: 1.66-3.51, respectively) and prolonged LOS (9.3 days; 95% CI: 9.2-9.4, 11.5 days; 95% CI: 11.5-11.6 and 13.3 days; 95% CI: 13.2-13.4, respectively). BSI with third-generation cephalosporin-susceptible Enterobacteriaceae (3GCSE) significantly increased LOS (5.9 days; 95% CI: 5.8-5.9) but not hazard of death (1.16; 95% CI: 0.98-1.36). 3GCRE significantly increased the hazard of death (1.63; 95% CI: 1.13-2.35), excess LOS (4.9 days; 95% CI: 1.1-8.7) and cost compared with susceptible strains, whereas meticillin resistance did not. The annual cost of 3GCRE BSI was higher than of MRSA BSI. While BSI with S. aureus had greater impact on mortality, excess LOS and cost than Enterobacteriaceae per infection, the impact of antimicrobial resistance was greater for Enterobacteriaceae.

  12. The health and economic burden of bloodstream infections caused by antimicrobial-susceptible and non-susceptible Enterobacteriaceae and Staphylococcus aureus in European hospitals, 2010 and 2011: a multicentre retrospective cohort study

    Science.gov (United States)

    Stewardson, Andrew J; Allignol, Arthur; Beyersmann, Jan; Graves, Nicholas; Schumacher, Martin; Meyer, Rodolphe; Tacconelli, Evelina; De Angelis, Giulia; Farina, Claudio; Pezzoli, Fabio; Bertrand, Xavier; Gbaguidi-Haore, Houssein; Edgeworth, Jonathan; Tosas, Olga; Martinez, Jose A; Ayala-Blanco, M Pilar; Pan, Angelo; Zoncada, Alessia; Marwick, Charis A; Nathwani, Dilip; Seifert, Harald; Hos, Nina; Hagel, Stefan; Pletz, Mathias; Harbarth, Stephan

    2016-01-01

    We performed a multicentre retrospective cohort study including 606,649 acute inpatient episodes at 10 European hospitals in 2010 and 2011 to estimate the impact of antimicrobial resistance on hospital mortality, excess length of stay (LOS) and cost. Bloodstream infections (BSI) caused by third-generation cephalosporin-resistant Enterobacteriaceae (3GCRE), meticillin-susceptible (MSSA) and -resistant Staphylococcus aureus (MRSA) increased the daily risk of hospital death (adjusted hazard ratio (HR) = 1.80; 95% confidence interval (CI): 1.34–2.42, HR = 1.81; 95% CI: 1.49–2.20 and HR = 2.42; 95% CI: 1.66–3.51, respectively) and prolonged LOS (9.3 days; 95% CI: 9.2–9.4, 11.5 days; 95% CI: 11.5–11.6 and 13.3 days; 95% CI: 13.2–13.4, respectively). BSI with third-generation cephalosporin-susceptible Enterobacteriaceae (3GCSE) significantly increased LOS (5.9 days; 95% CI: 5.8–5.9) but not hazard of death (1.16; 95% CI: 0.98–1.36). 3GCRE significantly increased the hazard of death (1.63; 95% CI: 1.13–2.35), excess LOS (4.9 days; 95% CI: 1.1–8.7) and cost compared with susceptible strains, whereas meticillin resistance did not. The annual cost of 3GCRE BSI was higher than of MRSA BSI. While BSI with S. aureus had greater impact on mortality, excess LOS and cost than Enterobacteriaceae per infection, the impact of antimicrobial resistance was greater for Enterobacteriaceae. PMID:27562950

  13. DNA microarray genotyping and virulence and antimicrobial resistance gene profiling of methicillin-resistant Staphylococcus aureus bloodstream isolates from renal patients.

    LENUS (Irish Health Repository)

    McNicholas, Sinead

    2012-02-01

    Thirty-six methicillin-resistant Staphylococcus aureus (MRSA) bloodstream isolates from renal patients were genetically characterized by DNA microarray analysis and spa typing. The isolates were highly clonal, belonging mainly to ST22-MRSA-IV. The immune evasion and enterotoxin gene clusters were found in 29\\/36 (80%) and 33\\/36 (92%) isolates, respectively.

  14. DNA microarray genotyping and virulence and antimicrobial resistance gene profiling of methicillin-resistant Staphylococcus aureus bloodstream isolates from renal patients.

    LENUS (Irish Health Repository)

    McNicholas, Sinead

    2011-12-01

    Thirty-six methicillin-resistant Staphylococcus aureus (MRSA) bloodstream isolates from renal patients were genetically characterized by DNA microarray analysis and spa typing. The isolates were highly clonal, belonging mainly to ST22-MRSA-IV. The immune evasion and enterotoxin gene clusters were found in 29\\/36 (80%) and 33\\/36 (92%) isolates, respectively.

  15. Microbial Quality and Antimicrobial Resistance of Staphylococcus aureus and Escherichia coli Isolated from Traditional Ice Cream in Hamadan City, West of Iran

    Directory of Open Access Journals (Sweden)

    Ghadimi

    2016-10-01

    Full Text Available Background Foodborne diseases are one of the most major public health concerns in the world. Ice cream flavors, especially the traditional ones, have a high potential for the transmission of the pathogenic bacteria. Objectives The aim of the current study is to investigate the microbiological status and antibiotic resistance of Escherichia coli and Staphylococcus aureus isolated from traditional ice cream. Methods A total of 114 traditional ice creams were randomly collected from retail stores in Hamadan, Iran. Samples were investigated for the total bacteria count (TBC and contamination with the coliform, Enterobacteriaceae and Salmonella as well as the prevalence and antibiotic resistance of Staphylococcus aureus and Escherichia coli. Results The count of Enterobacteriaceae (89.47%, mold and yeast (50%, coliform (40.35% and TBC (28.07% of samples was higher than Iran’s standard. Salmonella was not found in all samples. The prevalence of Staphylococcus aureus and Escherichia coli was confirmed in 50% and 37.72% of samples, respectively. Collected Escherichia coli had the highest antibiotic resistance to ampicillin 67.44%, nalidixic acid 39.53% and co-amoxyclav 37.21%. Staphylococcus aureus showed a higher antibiotic resistance to penicillin (82.46% of isolates and oxacillin (38% of isolates. Conclusions The results showed high contamination levels of traditional ice cream with spoilage and pathogenic microorganisms as well as considerable resistance of isolated Staphylococcus aureus and Escherichia coli to common antibiotics. Therefore, good hygienic practice during processing and personal hygiene should be considered to improve the quality of ice cream. In addition, it is necessary that the regulatory authorities carry out more control on the production centers of traditional ice cream.

  16. Characterization of antimicrobial properties on the growth of S. aureus of novel renewable blends of gliadins and chitosan of interest in food packaging and coating applications.

    Science.gov (United States)

    Fernandez-Saiz, P; Lagaron, J M; Hernandez-Muñoz, P; Ocio, M J

    2008-05-10

    The biocide properties of chitosan-based materials have been known for many years. However, typical antimicrobial formulations of chitosan, mostly chitosonium salts, are known to be very water sensitive materials which may impair their use in many application fields such as food packaging or food coating applications. This first work reports on the development and characterization of the antimicrobial properties of novel fully renewable blends of chitosan with more water-resistant gliadin proteins isolated from wheat gluten. Chitosan release to the nutrient broth from a wide range of blends was studied making use of the ninhydrin method. The results indicated that both pure chitosan and its blends with gliadins presented significant antimicrobial activity, which increased with increasing the amount of chitosan in the composite formulation as expected. The gliadins-chitosan blends showed good transparency and film-forming properties and better water resistance than pure chitosan. The release tests revealed that dissolution of the biocide glucosamine groups, i.e. the chitosan water soluble fractions, also increased with the amount of chitosan present in the formulation. The release of these groups was for the first time directly correlated with the antimicrobial properties exhibited by the blends. Thus, incorporation of chitosan into an insoluble biopolymer matrix was revealed as a very feasible strategy to generate novel chitosan-based antimicrobial materials with potential advantages, for instance active food packaging applications.

  17. Challenges in linking preclinical anti-microbial research strategies with clinical outcomes for device-associated infections

    Directory of Open Access Journals (Sweden)

    TF Moriarty

    2014-09-01

    Full Text Available Infections related to implanted medical devices have become a significant health care issue in recent decades. Increasing numbers of medical devices are in use, often in an aging population, and these devices are implanted against a background of increasing antibiotic-resistant bacterial populations. Progressively more antibiotic resistant infections, requiring ever more refined treatment options, are therefore predicted to emerge with greater frequency in the coming decades. Improvements in the prevention, diagnosis and treatment of these device-associated infections will remain priority targets both for clinicians and the translational research community charged with addressing these challenges. Preclinical strategies, predictive of ultimate clinical efficacy, should serve as a control point for effective translation of new technologies to clinical applications. The development of new anti-infective medical devices requires a validated preclinical testing protocol; however, reliable validation of experimental and preclinical antimicrobial methodologies currently suffers from a variety of technical limitations. These include the lack of agreement or standardisation of experimental protocols, a general lack of correlation between in vitro and in vivo preclinicalresults and lack of validation between in vivo preclinical implant infection models and clinical (human results. Device-associated infections pose additional challenges to practicing clinicians concerning diagnosis and treatment, both of which are complicated by the biofilms formed on the medical device. The critical challenges facing both preclinical research and clinical laboratories in improving both diagnosis and treatment of medical device-associated infections are the focus of this review.

  18. Antimicrobial peptides effectively kill a broad spectrum of Listeria monocytogenes and Staphylococcus aureus strains independently of origin, sub-type, or virulence factor expression

    DEFF Research Database (Denmark)

    Gottlieb, Caroline Trebbien; Thomsen, L.E.; Ingmer, H.;

    2008-01-01

    Background Host defense peptides (HDPs), or antimicrobial peptides (AMPs), are important components of the innate immune system that bacterial pathogens must overcome to establish an infection and HDPs have been suggested as novel antimicrobial therapeutics in treatment of infectious diseases......-type, and phenotypic behavior. Strains within each species were equally sensitive to HDPs and oxidative stress representing important components of the innate immune defense system. Four non-human peptides (protamine, plectasin, novicidin, and novispirin G10) were similar in activity profile (MIC value spectrum...

  19. The prevalence of antimicrobial resistance and carriage of virulence genes in Staphylococcus aureus isolated from food handlers in Kuwait City restaurants

    Directory of Open Access Journals (Sweden)

    Al-Mufti Siham

    2009-06-01

    Full Text Available Abstract Background Staphylococcus aureus is a major cause of food poisoning due to their ability to produce enterotoxins which if ingested in sufficient amounts results in sickness. Food handlers carrying enterotoxin-producing S. aureus in their noses or hands can contaminate food leading to food poisoning. We characterized 200 S. aureus obtained from food handlers in different restaurants for antibacterial resistance and the carriage of virulence genes. Findings Susceptibility to antibacterial agents was determined by disk diffusion and Etest. PCR was used to detect genes for accessory gene regulator (agr; capsular polysaccharide (cap 5 and 8, staphylococcal enterotoxins (SE, toxic shock syndrome toxin-1 (TSST-1 and Panton-Valentine leukocidin (PVL. Isolates were typed using pulsed-field gel electrophoresis. In total 185 (92.5% of the 200 isolates expressed resistance to antibacterial agents. They were resistant to penicillin G (82.0%, tetracycline (19.0%, erythromycin (2.5%, clindamycin (2.0%, trimethoprim (7.5%, kanamycin (2.5%, streptomycin (1.5%, ciprofloxacin (1.5%, fusidic acid (1.0% and cadmium acetate (68.0%. Seventy-six (38.0% and 114 (57.0% isolates had type 5 and type 8 capsular polysaccharides respectively. The agr types I, II and III alleles were detected in 50.5%, 20.0% and 23.5% of the isolates respectively. They contained genes for SEI (38.5%, SEG (24.0%, SEC (23.0%, SEB (12.5%, SEH (21.5%, SEA (11.0, SED (1.5%, SEE (1.5%, TSST-1 (4.0% and PVL (9.0%. Conclusion This study revealed a high prevalence of antibacterial resistance and virulence determinants in S. aureus from food handlers in Kuwait restaurants justifying the screening of food handlers to detect and treat carriers and protect restaurant customers from staphylococcal food poisoning.

  20. In vitro antimicrobial activity of Combretum molle (Combretaceae) against Staphylococcus aureus and Streptococcus agalactiae isolated from crossbred dairy cows with clinical mastitis.

    Science.gov (United States)

    Regassa, Fekadu; Araya, Mengistu

    2012-08-01

    Following the rapidly expanding dairy enterprise, mastitis has remained the most economically damaging disease. The objective of this study was mainly to investigate the in vitro antibacterial activities of ethanol extracts of Combretum molle (R.Br.Ex.G.Don) Engl & Diels (Combretaceae) against antibiotic-resistant and susceptible Staphylococcus aureus and Streptococcus agalactiae isolated from clinical cases of bovine mastitis using agar disc diffusion method. The leaf and bark extracts showed antibacterial activity against S. aureus at concentrations of 3 mg/ml while the stem and seed extract did not show any bioactivity. Although both leaf and bark extracts were handled in the same manner, the antibacterial activity of the bark extract against the bacterial strains had declined gradually to a lower level as time advanced after extraction. The leaf extract had sustained bioactivity for longer duration. The susceptibility of the bacteria to the leaf extract is not obviously different between S. aureus and S. agalactiae. Also, there was no difference in susceptibility to the leaf extract between the antibiotic-resistant and antibiotic-sensitive bacteria. Further phytochemical and in vivo efficacy and safety studies are required to evaluate the therapeutic value of the plant against bovine mastitis.

  1. A Novel Topical Combination Ointment with Antimicrobial Activity against Methicillin-Resistant Staphylococcus aureus, Gram-Negative Superbugs, Yeasts, and Dermatophytic Fungi

    Directory of Open Access Journals (Sweden)

    Kenneth S. Thomson, B.Ag.Sc, MS, PhD

    2016-01-01

    Conclusions: The results of this study suggest that this combination ointment has a broad in vitro spectrum of antimicrobial activity against both more common bacterial and fungal pathogens and may be particularly useful for treatment of infections by multidrug-resistant organisms. Additional studies are warranted to investigate the full clinical utility as a therapeutic agent and also for possible infection control interventions.

  2. Proteomic profile of hemolymph and detection of induced antimicrobial peptides in response to microbial challenge in Diatraea saccharalis (Lepidoptera: Crambidae).

    Science.gov (United States)

    Rocha, Iara Fernanda; Maller, Alexandre; de Cássia Garcia Simão, Rita; Kadowaki, Marina Kimiko; Angeli Alves, Luis Francisco; Huergo, Luciano Fernandes; da Conceição Silva, José Luis

    2016-04-29

    Insects are organisms extremely well adapted to diverse habitats, primarily due to their innate immune system, which provides them with a range of cellular and humoral responses against microorganisms. Lepidoptera hemolymph proteins involved in humoral responses are well known; however, there is a lack of knowledge about the sugarcane borer Diatraea saccharalis. In this present work, the hemolymph proteins of this pest insect were studied by applying proteomic methodologies. Two-dimensional electrophoresis (2-DE) gels of proteins extracted from naive larvae and larvae challenged with Escherichia coli (ATCC 11224) and Bacillus subtilis (ATCC 6623) showed an average of 300 spots, and 92 of these spots corresponded in all three 2-DE gels. Forty-one spots were excised and digested with trypsin and analyzed using mass spectrometry. After analysis, 10 proteins were identified, including some proteins of the immune system: β-defensin-like protein, Turandot A-like protein, attacin-like protein, peptidoglycan recognition protein and cyclophilin-like protein. Nine proteins were present in both experimental conditions; however, β-defensin-like protein was present only in hemolymph challenged by B. subtilis. Notably, attacin-like protein was strongly induced by challenge with E. coli, suggesting an immune response against the infection. However, antimicrobial activity was observed in the test zone of microbial growth inhibition of B. subtilis solely with the hemolymph extract of the larvae challenged with B. subtilis. We made for the first time a proteomic profile of the hemolymph of D. saccharalis in which it was possible to identify the presence of important proteins involved in the immune response.

  3. Minimum inhibitory concentration of ciprofloxacin in combination with hexahydroquinoline derivatives against Staphylococcus aureus

    OpenAIRE

    F Amin Harati; M Amini; Shahverdi AR; Pourmand, MR; Yousefi, M.

    2012-01-01

    Background: Staphylococcus aureus is the most common pathogen responsible for skin and soft tissue infections worldwide. Methicillin-resistant S. aureus is a major cause of both nosocomial and community acquired infections. The emergence of antimicrobial-resistant S. aureus is of global concern. Fluoroquinolone antimicrobials including ciprofloxacin, levofloxacin, and moxifloxacin are used to treat skin and soft tissue infections due to S. aureus. Emergence of ciprofloxacin resistance has inc...

  4. New antimicrobial contact catalyst killing antibiotic resistant clinical and waterborne pathogens

    Energy Technology Data Exchange (ETDEWEB)

    Guridi, A. [Biophysics Unit (CSIC, UPV/EHU), Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa (Spain); Diederich, A.-K. [University Medical Center Freiburg, Division of Infectious Diseases, Hugstetter Strasse 55, 79106 Freiburg (Germany); Biology II, Microbiology, Albert-Ludwigs-University Freiburg, Schänzlestrasse 1, 79104 Freiburg (Germany); Aguila-Arcos, S.; Garcia-Moreno, M. [Biophysics Unit (CSIC, UPV/EHU), Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa (Spain); Blasi, R.; Broszat, M. [University Medical Center Freiburg, Division of Infectious Diseases, Hugstetter Strasse 55, 79106 Freiburg (Germany); Biology II, Microbiology, Albert-Ludwigs-University Freiburg, Schänzlestrasse 1, 79104 Freiburg (Germany); Schmieder, W.; Clauss-Lendzian, E. [Biology II, Microbiology, Albert-Ludwigs-University Freiburg, Schänzlestrasse 1, 79104 Freiburg (Germany); Sakinc-Gueler, T. [University Medical Center Freiburg, Division of Infectious Diseases, Hugstetter Strasse 55, 79106 Freiburg (Germany); Andrade, R. [Advanced Research Facilities (SGIker), University of the Basque Country, UPV/EHU, 48940 Leioa (Spain); Alkorta, I. [Biophysics Unit (CSIC, UPV/EHU), Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa (Spain); Meyer, C.; Landau, U. [Largentec GmbH, Am Waldhaus 32, 14129 Berlin (Germany); Grohmann, E., E-mail: elisabeth.grohmann@googlemail.com [Biophysics Unit (CSIC, UPV/EHU), Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa (Spain); University Medical Center Freiburg, Division of Infectious Diseases, Hugstetter Strasse 55, 79106 Freiburg (Germany); Biology II, Microbiology, Albert-Ludwigs-University Freiburg, Schänzlestrasse 1, 79104 Freiburg (Germany)

    2015-05-01

    Microbial growth on medical and technical devices is a big health issue, particularly when microorganisms aggregate to form biofilms. Moreover, the occurrence of antibiotic-resistant bacteria in the clinical environment is dramatically growing, making treatment of bacterial infections very challenging. In search of an alternative, we studied a novel antimicrobial surface coating based on micro galvanic elements formed by silver and ruthenium with surface catalytic properties. The antimicrobial coating efficiently inhibited the growth of the nosocomial pathogens Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis and Enterococcus faecium as demonstrated by the growth inhibition on agar surface and in biofilms of antibiotic resistant clinical E. faecalis, E. faecium, and S. aureus isolates. It also strongly reduced the growth of Legionella in a drinking water pipeline and of Escherichia coli in urine. We postulate a mode of action of the antimicrobial material, which is independent of the release of silver ions. Thus, the novel antimicrobial coating could represent an alternative to combat microbial growth avoiding the toxic side effects of high levels of silver ions on eukaryotic cells. - Highlights: • The novel antimicrobial inhibits growth of clinical staphylococci and enterococci. • The novel antimicrobial inhibits growth of Legionella in drinking water. • A putative mode of action of the antimicrobial coating is presented.

  5. Antimicrobial activity of Mimosa tenuiflora (Willd. Poir. from Northeast Brazil against clinical isolates of Staphylococcus aureus Atividade antimicrobiana de Mimosa tenuiflora (Willd. Poir. do Nordeste do Brasil, contra isolados clínicos de Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Itácio Q. M. Padilha

    2010-03-01

    Full Text Available Mimosa tenuiflora is a native plant of Northeast Brazil where it is popularly known as ''jurema-preta'' and it is widely used in folk medicine. In this work the anti-Staphylococcus aureus activity of ethanol extract of M tenuiflora was evaluated by determination of minimum inhibitory concentration (MIC of clinical isolates by the agar dilution method, and by time-kill assay using a reference strain. MIC values against 30 isolates were 0,18 mg/mL (16/30 or 0,36 mg/mL (14/30, and also the reference strain. In the reference strains, at concentrations up to 4x MIC, only bacteriostatic effect was observed, but at 8x MIC a fast bactericidal effect was observed.A Mimosa tenuiflora é uma planta nativa da região Nordeste do Brasil onde é conhecida como jurema-preta sendo amplamente utilizada na medicina popular. No presente trabalho a atividade anti-Staphylococcus aureus do extrato etanólico da M. tenuiflora foi avaliada pela determinação da concentração inibitória mínima (CIM, pelo método da diluição em agar, em 30 isolados clínicos e pela cinética de inativação com a linhagem referência. Os valores da CIM foram 0,18 mg/mL em 16 isolados e 0,36 mg/mL nos demais, bem como na linhagem referência. A cinética de inativação mostrou apenas efeito bacteriostático nas concentrações do extrato até aquela correspondente a 4x CIM e um rápido efeito bactericida na concentração correspondente a 8x CIM.

  6. The challenge of antimicrobial resistance: new regulatory tools to support product development.

    Science.gov (United States)

    Tomayko, J F; Rex, J H; Tenero, D M; Goldberger, M; Eisenstein, B I

    2014-08-01

    The antibiotic pipeline is thin and lacks diversity, particularly for agents targeting Gram-negative pathogens. The reasons for our anemic global development pipeline are often summarized as (i) discovery of new antibiotics is difficult, (ii) clinical development of new antibiotics is difficult, and (iii) the economics for new antibiotics are unfavorable for the developer. Here, we review recent efforts directed at the second of these challenges.

  7. Effect of antimicrobial spice and herb extract combinations on Listeria monocytogenes, Staphylococcus aureus, and spoilage microflora growth on cooked ready-to-eat vacuum-packaged shrimp.

    Science.gov (United States)

    Weerakkody, Nimsha S; Caffin, Nola; Dykes, Gary A; Turner, Mark S

    2011-07-01

    Two spice and herb extract combinations from galangal (Alpinia galanga), rosemary (Rosmarinus officinalis), and lemon iron bark (Eucalyptus staigerana) were evaluated for their ability to inhibit the growth of inoculated Listeria monocytogenes and Staphylococcus aureus and naturally present spoilage microflora on cooked ready-to-eat shrimp stored for 16 days at 4 or 8 °C. A combination of galangal, rosemary, and lemon iron bark significantly reduced (P galangal and rosemary extract significantly reduced (P galangal, rosemary, and lemon iron bark extracts can be used to control the growth of spoilage microflora on ready-to-eat shrimp.

  8. Evasion of Neutrophil Killing by Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Will A. McGuinness

    2016-03-01

    Full Text Available Staphylococcus aureus causes many types of infections, ranging from self-resolving skin infections to severe or fatal pneumonia. Human innate immune cells, called polymorphonuclear leukocytes (PMNs or neutrophils, are essential for defense against S. aureus infections. Neutrophils are the most prominent cell type of the innate immune system and are capable of producing non-specific antimicrobial molecules that are effective at eliminating bacteria. Although significant progress has been made over the past few decades, our knowledge of S. aureus-host innate immune system interactions is incomplete. Most notably, S. aureus has the capacity to produce numerous molecules that are directed to protect the bacterium from neutrophils. Here we review in brief the role played by neutrophils in defense against S. aureus infection, and correspondingly, highlight selected S. aureus molecules that target key neutrophil functions.

  9. Antimicrobial Resistance Analysis and Detection of Methicillin-Resistant Staphylococcus aureus (MRSA)Among Staphylococcus aureus Strains Isolated from Bovine Mastitis%牛源金黄色葡萄球菌的耐药性及耐甲氧西林金黄色葡萄球菌的检测

    Institute of Scientific and Technical Information of China (English)

    苏洋; 蒲万霞; 陈智华; 邓海平

    2012-01-01

    [目的]了解内蒙古地区奶牛乳房炎金黄色葡萄球菌耐药性和耐甲氧西林金黄色葡萄球菌(MRSA)感染的情况,为奶牛乳房炎的防治提供理论依据.[方法]采用K-B纸片扩散法,检测分离自内蒙古地区38株金黄色葡萄球菌对17种药物的敏感性,同时用琼脂稀释法检测苯唑西林、万古霉素对金黄色葡萄球菌的最小抑菌浓度(MIC);再用头孢西丁、苯唑西林纸片扩散法、苯唑西林盐琼脂筛选法和PCR方法扩增mecA耐药基因对分离菌株进行全面MRSA检测.[结果]分离菌株对每种抗生素都有不同程度抗性,对氨苄西林、头孢拉丁、青霉素、复方新诺明、新生霉素和链霉素的耐药率都高于45%,而对氧氟沙星、丁胺卡那霉素、万古霉素、环丙沙星、庆大霉素和头孢唑林的敏感性高于90%,2株细菌的万古霉素MIC≥16 μg.mL-1;其中8株细菌的苯唑西林MIC≥8μg·mL-1,而其它菌株的苯唑西林MIC≤2μg·mL-1,分离菌株多重耐药情况严重,耐受3种及3种以上药物的菌株占84.21%,其中4株细菌能同时耐受9种不同抗菌药物;16 (42.11%)株细菌被检测携带mecA耐药基因,而仅有其中7株的苯唑西林MIC≥4 μg·mL-1;头孢西丁、苯唑西林纸片扩散法和苯唑西林盐琼脂筛选法分别检出7株、10株和7株表型为MRSA的菌株.[结论]分离菌株的耐药性和多重耐药现象较为严重,被调查地区奶牛场中已经存在MRSA和OS-MRSA感染情况,且感染率高.%[Objective] The aim of the study is to investigate the antimicrobial resistance of S. aureus (Science) and to detect the presence of methicillin-resistant S. aureus (MRSA) among S. aureus strains isolated from bovine mastitis in Inner Mongolia, and to provide credible theory evidence for prevention and treatment of bovine mastitis. [Method] K-B.disk diffusion method was used to test drug sensitivity of 38 total strains of S.aureus to 17 commonly used antibiotics

  10. Fast disinfecting antimicrobial surfaces.

    Science.gov (United States)

    Madkour, Ahmad E; Dabkowski, Jeffery M; Nusslein, Klaus; Tew, Gregory N

    2009-01-20

    Silicon wafers and glass surfaces were functionalized with facially amphiphilic antimicrobial copolymers using the "grafting from" technique. Surface-initiated atom transfer radical polymerization (ATRP) was used to grow poly(butylmethacrylate)-co-poly(Boc-aminoethyl methacrylate) from the surfaces. Upon Boc-deprotection, these surfaces became highly antimicrobial and killed S. aureus and E. coli 100% in less than 5 min. The molecular weight and grafting density of the polymer were controlled by varying the polymerization time and initiator surface density. Antimicrobial studies showed that the killing efficiency of these surfaces was independent of polymer layer thickness or grafting density within the range of surfaces studied.

  11. Chemical modifications of a natural xanthone and antimicrobial activity against multidrug resistant Staphylococcus aureus and cytotoxicity against human tumor cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Micheletti, Ana Camila; Honda, Neli Kika; Lima, Denis Pires de; Beatriz, Adilson [Universidade Federal de Mato Grosso do Sul (DQ/UFMS), Campo Grande, MS (Brazil). Dept. de Quimica; Sant' ana, Maria Rita; Carvalho, Nadia Cristina Pereira [Universidade Federal de Mato Grosso do Sul (SAC/UFMS), Campo Grande, MS (Brazil). Secao de Analises Clinicas; Matos, Maria de Fatima Cepa; Queiroz, Lyara Meira Marinho; Bogo, Danielle [Universidade Federal de Mato Grosso do Sul (DFB/UFMS), Campo Grande, MS (Brazil). Dept. de Farmacia-Bioquimica; Zorzatto, Jose Roberto [Universidade Federal de Mato Grosso do Sul (DQ/UFMS), Campo Grande, MS (Brazil). Faculdade de Computacao

    2011-07-01

    A series of 15 {omega}-aminoalkoxylxanthones containing methyl, ethyl, propyl, tert-butylamino and piperidinyl moieties were synthesized from a natural xanthone isolated from a lichen species. These compounds were tested for their in vitro antibacterial properties against Gram-positive and Gram-negative bacteria and cytotoxicity against a number of human tumor cell lines was too evaluated. The newly synthesized derivatives revealed selective activity against Staphylococcus aureus (Gram-positive), and the most promising results are for a multidrug resistant strain, for which six of these compounds showed good activity (MICs 4 {mu}g/mL). Many derivatives inhibited tumor cells growth and most compounds were active on multiple lines. (author)

  12. Beyond conventional antibiotics for the future treatment of methicillin-resistant Staphylococcus aureus infections: two novel alternatives.

    LENUS (Irish Health Repository)

    Fitzgerald-Hughes, Deirdre

    2012-08-01

    The majority of antibiotics currently used to treat methicillin-resistant Staphylococus aureus (MRSA) infections target bacterial cell wall synthesis or protein synthesis. Only daptomycin has a novel mode of action. Reliance on limited targets for MRSA chemotherapy, has contributed to antimicrobial resistance. Two alternative approaches to the treatment of S. aureus infection, particularly those caused by MRSA, that have alternative mechanisms of action and that address the challenge of antimicrobial resistance are cationic host defence peptides and agents that target S. aureus virulence. Cationic host defence peptides have multiple mechanisms of action and are less likely than conventional agents to select resistant mutants. They are amenable to modifications that improve their stability, effectiveness and selectivity. Some cationic defence peptides such as bactenecin, mucroporin and imcroporin have potent in vitro bactericidal activity against MRSA. Antipathogenic agents also have potential to limit the pathogenesis of S aureus. These are generally small molecules that inhibit virulence targets in S. aureus without killing the bacterium and therefore have limited capacity to promote resistance development. Potential antipathogenic targets include the sortase enzyme system, the accessory gene regulator (agr) and the carotenoid biosynthetic pathway. Inhibitors of these targets have been identified and these may have potential for further development.

  13. Valproic acid induces antimicrobial compound production in Doratomyces microspores.

    Directory of Open Access Journals (Sweden)

    Christoph eZutz

    2016-04-01

    Full Text Available One of the biggest challenges in public health is the rising number of antibiotic resistant pathogens and the lack of novel antibiotics. In recent years there is a rising focus on fungi as sources of antimicrobial compounds due to their ability to produce a large variety of bioactive compounds and the observation that virtually every fungus may still contain yet unknown so called cryptic, often silenced, compounds. These putative metabolites could include novel bioactive compounds. Considerable effort is spent on methods to induce production of these cryptic metabolites. One approach is the use of small molecule effectors, potentially influencing chromatin landscape in fungi. We observed that the supernatant of the fungus Doratomyces (D. microsporus treated with valproic acid (VPA displayed antimicrobial activity against Staphylococcus (S. aureus and two methicillin resistant clinical S. aureus isolates. VPA treatment resulted in enhanced production of seven antimicrobial compounds: cyclo-(L-proline-L-methionine (cPM, p-hydroxybenzaldehyde, cyclo-(phenylalanine-proline (cFP, indole-3-carboxylic acid, phenylacetic acid (PAA and indole-3-acetic acid. The production of the antimicrobial compound phenyllactic acid was exclusively detectable after VPA treatment. Furthermore three compounds, cPM, cFP and PAA, were able to boost the antimicrobial activity of other antimicrobial compounds. cPM, for the first time isolated from fungi, and to a lesser extent PAA, are even able to decrease the minimal inhibitory concentration of ampicillin in MRSA strains. In conclusion we could show in this study that VPA treatment is a potent tool for induction of cryptic antimicrobial compound production in fungi, and that the induced compounds are not exclusively linked to the secondary metabolism. Furthermore this is the first discovery of the rare diketopiperazine cPM in fungi. Additionally we could demonstrate that cPM and PAA boost antibiotic activity against

  14. Valproic Acid Induces Antimicrobial Compound Production in Doratomyces microspores

    Science.gov (United States)

    Zutz, Christoph; Bacher, Markus; Parich, Alexandra; Kluger, Bernhard; Gacek-Matthews, Agnieszka; Schuhmacher, Rainer; Wagner, Martin; Rychli, Kathrin; Strauss, Joseph

    2016-01-01

    One of the biggest challenges in public health is the rising number of antibiotic resistant pathogens and the lack of novel antibiotics. In recent years there is a rising focus on fungi as sources of antimicrobial compounds due to their ability to produce a large variety of bioactive compounds and the observation that virtually every fungus may still contain yet unknown so called “cryptic,” often silenced, compounds. These putative metabolites could include novel bioactive compounds. Considerable effort is spent on methods to induce production of these “cryptic” metabolites. One approach is the use of small molecule effectors, potentially influencing chromatin landscape in fungi. We observed that the supernatant of the fungus Doratomyces (D.) microsporus treated with valproic acid (VPA) displayed antimicrobial activity against Staphylococcus (S.) aureus and two methicillin resistant clinical S. aureus isolates. VPA treatment resulted in enhanced production of seven antimicrobial compounds: cyclo-(L-proline-L-methionine) (cPM), p-hydroxybenzaldehyde, cyclo-(phenylalanine-proline) (cFP), indole-3-carboxylic acid, phenylacetic acid (PAA) and indole-3-acetic acid. The production of the antimicrobial compound phenyllactic acid was exclusively detectable after VPA treatment. Furthermore three compounds, cPM, cFP, and PAA, were able to boost the antimicrobial activity of other antimicrobial compounds. cPM, for the first time isolated from fungi, and to a lesser extent PAA, are even able to decrease the minimal inhibitory concentration of ampicillin in MRSA strains. In conclusion we could show in this study that VPA treatment is a potent tool for induction of “cryptic” antimicrobial compound production in fungi, and that the induced compounds are not exclusively linked to the secondary metabolism. Furthermore this is the first discovery of the rare diketopiperazine cPM in fungi. Additionally we could demonstrate that cPM and PAA boost antibiotic activity

  15. Quorum sensing inhibitory drugs as next generation antimicrobials: worth the effort?

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Givskov, M.

    2008-01-01

    , elderly, immunocompromised, and hospitalized patients are susceptible to infections caused by bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis. These bacteria form chronic, biofilm-based infections, which are challenging because bacterial cells living...... as biofilms are more tolerant to antibiotics than their planktonic counterparts. Therefore, research should identify new antimicrobial agents and their corresponding targets to decrease the biofilm-forming capability or persistence of the infectious bacteria. Here, we review one such drug target: bacterial...

  16. Aplicação de estudos de QSAR-2D em derivados 5-nitro-2-tiofilidênicos com atividade antimicrobiana frente a Staphylococcus aureus multi-resistente (MRSA 2D QSAR studies of 5-nitro-2-thiophylidene derivatives with antimicrobial activity against multidrug-resistant Staphylococcus aureus (MRSA

    Directory of Open Access Journals (Sweden)

    Andrea Masunari

    2006-06-01

    Full Text Available O avanço de estudos de QSAR (Quantitative Structure-Activity Relationships como método de modificação molecular racionalmente planejada vem se constituindo, nos últimos anos, em alternativa bastante viável para o desenvolvimento de ligantes candidatos potenciais a fármacos. Sendo assim, aliando a excelente aplicabilidade deste método com o fenômeno de multi-resistência bacteriana, realizou-se, neste trabalho, o estudo, em duas dimensões, das relações quantitativas entre a estrutura química e a potência antimicrobiana de 5-nitro-2-tiofilideno benzidrazidas substituídas, considerando faixa de hidrofobicidade ótima pré-determinada experimentalmente. A aplicação da Análise de Hansch/Fujita possibilitou a determinação da influência de descritores estruturais de caráter físico-químico sobre a referida atividade, indicando ser a hidrofobicidade a propriedade de maior impacto no desempenho da atividade biológica analisada. Evidenciou-se, a partir das correlações obtidas, o forte potencial de derivados 5-nitro-2-tiofilidênicos como possível alternativa para o desenvolvimento racional, em nível molecular, de novos fármacos com atividade antimicrobiana.With the constant advance of QSAR (Quantitative Structure-Activity Relationships studies as molecular modification methodology, a frequent application of this procedure in many science areas was observed. Besides, the rational ligand development for many diseases has been growing in recent years. Thus, in order to ally these medicinal chemistry advances with the necessity to combat the high incidence of antibiotic-resistant microorganisms, the purpose of this study was the 2D-QSAR study of p-substituted 5-nitro-2-thiophylidene derivatives with antimicrobial activity against Staphylococcus aureus, considering hydrophobicity range experimentally determined. The statistical significant correlations obtained by Hansch/Fujita Analysis showed significant influence of

  17. Pathogenesis of Staphylococcus aureus abscesses.

    Science.gov (United States)

    Kobayashi, Scott D; Malachowa, Natalia; DeLeo, Frank R

    2015-06-01

    Staphylococcus aureus causes many types of human infections and syndromes-most notably skin and soft tissue infections. Abscesses are a frequent manifestation of S. aureus skin and soft tissue infections and are formed, in part, to contain the nidus of infection. Polymorphonuclear leukocytes (neutrophils) are the primary cellular host defense against S. aureus infections and a major component of S. aureus abscesses. These host cells contain and produce many antimicrobial agents that are effective at killing bacteria, but can also cause non-specific damage to host tissues and contribute to the formation of abscesses. By comparison, S. aureus produces several molecules that also contribute to the formation of abscesses. Such molecules include those that recruit neutrophils, cause host cell lysis, and are involved in the formation of the fibrin capsule surrounding the abscess. Herein, we review our current knowledge of the mechanisms and processes underlying the formation of S. aureus abscesses, including the involvement of polymorphonuclear leukocytes, and provide a brief overview of therapeutic approaches.

  18. Study on the antimicrobial activity of Ethanol Extract of Propolisagainst enterotoxigenic Methicillin-Resistant Staphylococcus aureus in lab prepared Ice-cream

    Directory of Open Access Journals (Sweden)

    T A El-Bassiony

    2012-06-01

    Full Text Available The objective of this study was to investigate the antimicrobial activity of ethanol extract of propolis against enterotoxigenic strain of MRSA which inoculated into lab prepared ice cream. EEP was added to ice cream in 3 concentrations (150, 300 and 600 mg/L. The prepared ice cream was divided into 2 groups, one stored at freezer temp. at (-5˚C, while the other was kept in deep freezer temp. at (-20˚C. MRSA could not be counted from the 4th, 2nd and 1st week of storage at freezer temp, while at deep freezer temp. MRSA could not be enumerated from the 3rd, 1st week and 3rd day of storage in portions contained 150, 300 and 600mg/L EEP, respectively. [Vet. World 2012; 5(3.000: 155-159

  19. Investigation into the potential of sub-lethal photodynamic antimicrobial chemotherapy (PACT) to reduce susceptibility of meticillin-resistant Staphylococcus aureus (MRSA) to antibiotics

    Science.gov (United States)

    Cassidy, C. M.; Donnelly, R. F.; Tunney, M. M.

    2009-06-01

    In PACT, a combination of a sensitising drug and visible light cause the selective destruction of microbial cells via singlet oxygen production. As singlet oxygen is a non-specific oxidizing agent and is only present during illumination, development of resistance to this treatment is thought to be unlikely. However, in response to oxidative stress, bacteria can up-regulate oxidative stress genes and associated antibiotic resistance genes. The up-regulation of these genes and potential transfer of genetic material may result in a resistant bacterial population. This study determined whether treatment of clinically isolated meticillin resistant Staphylococcus aureus (MRSA) strains with sub-lethal doses of methylene blue (MB) and meso-tetra (N-methyl-4-pyridyl) porphine tetra tosylate (TMP)-PACT resulted in reduced susceptibility to antibiotics and previously lethal PACT. Exposure of strains to sub-lethal doses of photosensitizer in combination with light had no effect on susceptibility to previously lethal photosensitization. Furthermore, exposure to sub-lethal concentrations of both photosensitizers caused no significant changes in the minimum inhibitory concentration (MIC) for each strain tested. Any differences in susceptibility were not significant as they did not cross breakpoints between resistant and susceptible for any organism or antibiotic tested. Therefore, PACT remains an attractive alternative option for treatment of MRSA infections.

  20. Optimization and structure-activity relationships of a series of potent inhibitors of methicillin-resistant Staphylococcus aureus (MRSA) pyruvate kinase as novel antimicrobial agents.

    Science.gov (United States)

    Kumar, Nag S; Amandoron, Emily A; Cherkasov, Artem; Finlay, B Brett; Gong, Huansheng; Jackson, Linda; Kaur, Sukhbir; Lian, Tian; Moreau, Anne; Labrière, Christophe; Reiner, Neil E; See, Raymond H; Strynadka, Natalie C; Thorson, Lisa; Wong, Edwin W Y; Worrall, Liam; Zoraghi, Roya; Young, Robert N

    2012-12-15

    A novel series of hydrazones were synthesized and evaluated as inhibitors of methicillin-resistant Staphylococcus aureus (MRSA) pyruvate kinase (PK). PK has been identified as one of the most highly connected 'hub proteins' in MRSA. PK has been shown to be critical for bacterial survival which makes it a potential target for development of novel antibiotics and the high degree of connectivity implies it should be very sensitive to mutations and thus less able to develop resistance. PK is not unique to bacteria and thus a critical requirement for such a PK inhibitor would be that it does not inhibit the homologous human enzyme(s) at therapeutic concentrations. Several MRSA PK inhibitors (including 8d) were identified using in silico screening combined with enzyme assays and were found to be selective for bacterial enzyme compared to four human PK isoforms (M1, M2, R and L). However these lead compounds did not show significant inhibitory activity for MRSA growth presumably due to poor bacterial cell penetration. Structure-activity relationship (SAR) studies were carried out on 8d 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. These inhibitors bind in two elongated flat clefts found at the minor interfaces in the homo-tetrameric enzyme complex and the observed SAR is in keeping with the size and electronic constraints of these binding sites. Access to the corresponding sites in the human enzyme is blocked.

  1. Studies on antimicrobial activity of Poncirus trifoliata ethyl extract fraction against methicillin-resistant Staphylococcus aureus and to elucidate its antibacterial mechanism.

    Science.gov (United States)

    Eom, Sung-Hwan; Jung, Yeoun-Joong; Lee, Dae-Sung; Yim, Mi-Jin; Kim, Hye Seon; Lee, Sang-Hoon; Myeong, Jeong-In; Lee, Jinhwan; Kim, Hyun-Woo; Kim, Kyoung-Ho; Lee, Myung-Suk; Kim, Young-Mog

    2016-01-01

    Traditional medicinal plants contain a wide variety of chemicals that have potent antibacterial activity. To find an alternative agent of overcoming the problems of methicillin-resistant Staphylococcus aureus (MRSA), the antibacterial mechanism of Ponciruss trifoliata against MRSA was investigated. Ethyl acetate (EtOAc)-soluble extract of P. trifoliata methanolic extract was evaluated for antibacterial activity using minimum inhibitory concentration (MIC). An EtOAc sub-fraction 08 (EA08) from silica-gel open column chromatography exhibited strong anti-MRSA activity. Apart from the study to isolate single compound from EA08, a synergistic antibacterial effect between the sub-fraction and β-lactam antibiotics against MRSA was determined. In order to elucidate the antibacterial restoring mechanism of EA08 on MRSA, mRNA expression of mecA gene and production penicillin-binding protein 2a (PBP2a) encoded by mecA gene were monitored. EA 08 showed the strongest antibacterial activity with MIC value of 256 μg ml(-1). MIC of oxacillin against MRSA was dramatically reduced from 512 to 16 μg ml(-1) in combination with 256 μg ml(-1) of EA08. The fractional inhibitory concentration index of oxacillin was measured at 0.53 in combination with EA08 against MRSA, suggesting that EA08-oxacillin combinations exert synergetic effect against MRSA. The analysis of RT-PCR and Western blotting profiles revealed that EA08 inhibited mRNA expression of mecA gene and production PBP2a, which is a key determinant for β-lactam antibiotic resistance, in a dose-dependent manner. These results indicated that EA08 eventually led to the reduction or inhibition of PBP2a production through translational inhibition in MRSA.

  2. A mouse model of post-arthroplasty Staphylococcus aureus joint infection to evaluate in vivo the efficacy of antimicrobial implant coatings.

    Directory of Open Access Journals (Sweden)

    Nicholas M Bernthal

    Full Text Available BACKGROUND: Post-arthroplasty infections represent a devastating complication of total joint replacement surgery, resulting in multiple reoperations, prolonged antibiotic use, extended disability and worse clinical outcomes. As the number of arthroplasties in the U.S. will exceed 3.8 million surgeries per year by 2030, the number of post-arthroplasty infections is projected to increase to over 266,000 infections annually. The treatment of these infections will exhaust healthcare resources and dramatically increase medical costs. METHODOLOGY/PRINCIPAL FINDINGS: To evaluate novel preventative therapeutic strategies against post-arthroplasty infections, a mouse model was developed in which a bioluminescent Staphylococcus aureus strain was inoculated into a knee joint containing an orthopaedic implant and advanced in vivo imaging was used to measure the bacterial burden in real-time. Mice inoculated with 5x10(3 and 5x10(4 CFUs developed increased bacterial counts with marked swelling of the affected leg, consistent with an acute joint infection. In contrast, mice inoculated with 5x10(2 CFUs developed a low-grade infection, resembling a more chronic infection. Ex vivo bacterial counts highly correlated with in vivo bioluminescence signals and EGFP-neutrophil fluorescence of LysEGFP mice was used to measure the infection-induced inflammation. Furthermore, biofilm formation on the implants was visualized at 7 and 14 postoperative days by variable-pressure scanning electron microscopy (VP-SEM. Using this model, a minocycline/rifampin-impregnated bioresorbable polymer implant coating was effective in reducing the infection, decreasing inflammation and preventing biofilm formation. CONCLUSIONS/SIGNIFICANCE: Taken together, this mouse model may represent an alternative pre-clinical screening tool to evaluate novel in vivo therapeutic strategies before studies in larger animals and in human subjects. Furthermore, the antibiotic-polymer implant coating

  3. Concentração mínima inibitória de dez antimicrobianos para amostras de Staphylococcus aureus isoladas de infecção intramamária bovina Minimum inhibitory concentrations for ten antimicrobial agents against Staphylococcus aureus from bovine intramammary infection

    Directory of Open Access Journals (Sweden)

    M.A.V.P. Brito

    2001-10-01

    cases of mastitis, 66 from subclinical infections and 22 from chronic infections. The chronic infection strains were isolated from the same mammary quarters of nine cows of one herd over a period of 13 months. The MIC was performed on Mueller Hinton agar and concentrations, ranging from 0.015 to 128µgml-1, were evaluated for each antimicrobial agent. The American Type Culture Collection (ATCC recommended quality control strains, S. aureus ATCC 29213, Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853, were included on each batch of test. All strains were susceptible to cephalothin, erythromycin, gentamicin, norfloxacin and oxacillin, 91% were susceptible to tetracycline (MIC50: 0.5µgml-1 and tylosin (MIC50: 2.0µgml-1, 65% to ampicillin (MIC50: 0.125µgml-1 and penicillin G (MIC50: 0.06µgml-1. All strains but one in the intermediate pattern, were susceptible to neomycin (MIC50: 0.5µgml-1. The resistance levels to ampicillin and penicillin were higher in strains isolated from clinical and subclinical (positive scores on CMT cases (P or = 0.125µgml-1 to penicillin were positive for ß-lactamase production.

  4. Methicillin resistant Staphylococcus aureus ST398 in veal calf farming: human MRSA carriage related with animal antimicrobial usage and farm hygiene.

    Directory of Open Access Journals (Sweden)

    Haitske Graveland

    Full Text Available INTRODUCTION: Recently a specific MRSA sequence type, ST398, emerged in food production animals and farmers. Risk factors for carrying MRSA ST398 in both animals and humans have not been fully evaluated. In this cross-sectional study, we investigated factors associated with MRSA colonization in veal calves and humans working and living on these farms. METHODS: A sample of 102 veal calf farms were randomly selected and visited from March 2007-February 2008. Participating farmers were asked to fill in a questionnaire (n = 390 to identify potential risk factors. A nasal swab was taken from each participant. Furthermore, nasal swabs were taken from calves (n = 2151. Swabs were analysed for MRSA by selective enrichment and suspected colonies were confirmed as MRSA by using slide coagulase test and PCR for presence of the mecA-gene. Spa types were identified and a random selection of each spa type was tested with ST398 specific PCR. The Sequence Type of non ST398 strains was determined. Data were analyzed using logistic regression analysis. RESULTS: Human MRSA carriage was strongly associated with intensity of animal contact and with the number of MRSA positive animals on the farm. Calves were more often carrier when treated with antibiotics, while farm hygiene was associated with a lower prevalence of MRSA. CONCLUSION: This is the first study showing direct associations between animal and human carriage of ST398. The direct associations between animal and human MRSA carriage and the association between MRSA and antimicrobial use in calves implicate prudent use of antibiotics in farm animals.

  5. Changes in Holstein cow milk and serum proteins during intramammary infection with three different strains of Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Robert Claude

    2011-09-01

    Full Text Available Abstract Background Staphylococcus aureus is one of the most prevalent pathogens to cause mastitis in dairy cattle. Intramammary infection of dairy cows with S. aureus is often subclinical, due to the pathogen's ability to evade the innate defense mechanisms, but this can lead to chronic infection. A sub-population of S. aureus, known as small colony variant (SCV, displays atypical phenotypic characteristics, causes persistent infections, and is more resistant to antibiotics than parent strains. Therefore, it was hypothesized that the host immune response will be different for SCV than its parental or typical strains of S. aureus. In this study, the local and systemic immune protein responses to intramammary infection with three strains of S. aureus, including a naturally occurring bovine SCV strain (SCV Heba3231, were characterized. Serum and casein-depleted milk cytokine levels (interleukin-8, interferon-γ, and transforming growth factor-β1, as well as serum haptoglobin concentrations were monitored over time after intramammary infection with each of the three S. aureus strains. Furthermore, comparative proteomics was used to evaluate milk proteome profiles during acute and chronic phases of S. aureus intramammary infection. Results Serum IL-8, IFN-γ, and TGF-β1 responses differed in dairy cows challenged with different strains of S. aureus. Changes in overall serum haptoglobin concentrations were observed for each S. aureus challenge group, but there were no significant differences observed between groups. In casein-depleted milk, strain-specific differences in the host IFN-γ response were observed, but inducible IL-8 and TGF-β1 concentrations were not different between groups. Proteomic analysis of the milk following intramammary infection revealed unique host protein expression profiles that were dependent on the infecting strain as well as phase of infection. Notably, the protein, component-3 of the proteose peptone (CPP3, was

  6. Antimicrobial polymers.

    Science.gov (United States)

    Jain, Anjali; Duvvuri, L Sailaja; Farah, Shady; Beyth, Nurit; Domb, Abraham J; Khan, Wahid

    2014-12-01

    Better health is basic requirement of human being, but the rapid growth of harmful pathogens and their serious health effects pose a significant challenge to modern science. Infections by pathogenic microorganisms are of great concern in many fields such as medical devices, drugs, hospital surfaces/furniture, dental restoration, surgery equipment, health care products, and hygienic applications (e.g., water purification systems, textiles, food packaging and storage, major or domestic appliances etc.) Antimicrobial polymers are the materials having the capability to kill/inhibit the growth of microbes on their surface or surrounding environment. Recently, they gained considerable interest for both academic research and industry and were found to be better than their small molecular counterparts in terms of enhanced efficacy, reduced toxicity, minimized environmental problems, resistance, and prolonged lifetime. Hence, efforts have focused on the development of antimicrobial polymers with all desired characters for optimum activity. In this Review, an overview of different antimicrobial polymers, their mechanism of action, factors affecting antimicrobial activity, and application in various fields are given. Recent advances and the current clinical status of these polymers are also discussed.

  7. Resistance in Staphylococcus Aureus: The Never-Ending Story

    Directory of Open Access Journals (Sweden)

    Orlović Jovan

    2016-09-01

    Full Text Available Combating Staphylococcus aureus (S. aureus infections using antibacterial drugs is actually an ongoing effort to overcome resistance mechanism of this microorganism. In this paper, we discussed (1 the mechanisms of resistance to some of the most commonly used antimicrobial agents in the treatment of S. aureus: methicillin, vancomicyn and quinolones. In addition, (2 efflux pump mechanisms involved in maintaining homeostasis in the presence of compounds that inhibit S. aureus growth and reproduction, as well as mechanisms of resistance to a number of antibiotics, have been reviewed.

  8. Induction of a gloverin-like antimicrobial polypeptide in the sugarcane borer Diatraea saccharalis challenged by septic injury

    Directory of Open Access Journals (Sweden)

    J.L.C. Silva

    2010-05-01

    Full Text Available Diatraea saccharalis (Fabricius, 1794 (Lepidoptera: Crambidae is an important pest for Brazilian sugarcane. In the present study, we detected two distinct spots in hemolymph from septic injured larvae (HDs1 and HDs2, which are separated by 2DE gel electrophoresis. Both spots were subjected to in-gel tryptic digestion and MALDI-TOF/TOF analysis, which revealed the sequence VFGTLGSDDSGLFGK present in both HDs1 and HDs2. This sequence had homology and 80% identity with specific Lepidoptera antimicrobial peptides called gloverins. Analyses using the ImageMaster 2D software showed pI 8.94 of the HDs1 spot, which is similar to that described to Hyalophora gloveri gloverin (pI 8.5. Moreover, the 14-kDa molecular mass of the spot HDs1 is compatible to that of gloverins isolated from the hemolymph of Trichoplusia ni, Helicoverpa armigera and H. gloveri. Antimicrobial assays with partially purified fractions containing the HDs1 and HDs2 polypeptides demonstrated activity against Escherichia coli. This is the first report of antimicrobial polypeptides in D. saccharalis, and the identification of these peptides may help in the generation of new strategies to control this pest.

  9. Induction of a gloverin-like antimicrobial polypeptide in the sugarcane borer Diatraea saccharalis challenged by septic injury.

    Science.gov (United States)

    Silva, J L C; Barbosa, J F; Bravo, J P; Souza, E M de; Huergo, L F; Pedrosa, F O; Esteves, E; Daffre, S; Fernandez, M A

    2010-05-01

    Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae) is an important pest for Brazilian sugarcane. In the present study, we detected two distinct spots in hemolymph from septic injured larvae (HDs1 and HDs2), which are separated by 2DE gel electrophoresis. Both spots were subjected to in-gel tryptic digestion and MALDI-TOF/TOF analysis, which revealed the sequence VFGTLGSDDSGLFGK present in both HDs1 and HDs2. This sequence had homology and 80% identity with specific Lepidoptera antimicrobial peptides called gloverins. Analyses using the ImageMaster 2D software showed pI 8.94 of the HDs1 spot, which is similar to that described to Hyalophora gloveri gloverin (pI 8.5). Moreover, the 14-kDa molecular mass of the spot HDs1 is compatible to that of gloverins isolated from the hemolymph of Trichoplusia ni, Helicoverpa armigera and H. gloveri. Antimicrobial assays with partially purified fractions containing the HDs1 and HDs2 polypeptides demonstrated activity against Escherichia coli. This is the first report of antimicrobial polypeptides in D. saccharalis, and the identification of these peptides may help in the generation of new strategies to control this pest.

  10. Antimicrobial screening of Cichorium intybus seed extracts

    Directory of Open Access Journals (Sweden)

    Tauseef shaikh

    2016-11-01

    Full Text Available Medicinal plants play an important role in the field of natural products and human health care system. Chemical constituents present in the various parts of the plants can resist to parasitic attack by using several defense mechanisms. One such mechanism is the synthesis of antimicrobial compound. Cichorium intybus is one of the important medicinal plants which belong to Asteraceae family. In the present work, antimicrobial screening of C. intybus seed extract was studied by agar well diffusion assay by using aqueous and organic extracts. The pathogenic microorganisms tested include Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans and Escherichia coli. All the seed extracts showed antimicrobial activity against tested microorganisms whereas S. aureus was found to be most sensitive against aqueous extract and had the widest zone of inhibition. Ethyl acetate and ethanol extract were found to be significant against P. aeruginosa and S. aureus. The results obtained from antimicrobial screening scientifically support the effectiveness of the medicinal plant.

  11. Trends in the susceptibility of methicillin-resistant Staphylococcus aureus to nine antimicrobial agents, including ceftobiprole, nemonoxacin, and tyrothricin: results from the Tigecycline In Vitro Surveillance in Taiwan (TIST) study, 2006-2010.

    Science.gov (United States)

    Chen, Y-H; Liu, C-Y; Ko, W-C; Liao, C-H; Lu, P-L; Huang, C-H; Lu, C-T; Chuang, Y-C; Tsao, S-M; Chen, Y-S; Liu, Y-C; Chen, W-Y; Jang, T-N; Lin, H-C; Chen, C-M; Shi, Z-Y; Pan, S-C; Yang, J-L; Kung, H-C; Liu, C-E; Cheng, Y-J; Liu, J-W; Sun, W; Wang, L-S; Yu, K-W; Chiang, P-C; Lee, M-H; Lee, C-M; Hsu, G-J; Hsueh, P-R

    2014-02-01

    This study investigated the in vitro susceptibilities of methicillin-resistant Staphylococcus aureus (MRSA) to nine antimicrobial agents in Taiwan. A total of 1,725 isolates were obtained from 20 hospitals throughout Taiwan from 2006 to 2010. The minimum inhibitory concentrations (MICs) of the nine agents were determined by the agar dilution method. The MICs of mupirocin and tyrothricin were determined for 223 MRSA isolates collected from 2009 to 2010. For vancomycin, 99.7 % were susceptible; however, 30.0 % (n = 517) exhibited MICs of 2 μg/ml and 0.3 % (n = 6) demonstrated intermediate susceptibility (MICs of 4 μg/ml). Nearly all isolates (≥ 99.9 %) were susceptible to teicoplanin, linezolid, and daptomycin. The MIC90 values were 2 μg/ml for ceftobiprole and 1 μg/ml for nemonoxacin. The MIC90 values of mupirocin and tyrothricin were 0.12 and 4 μg/ml, respectively. MIC creep was noted for daptomycin during this period, but not for vancomycin, teicoplanin, linezolid, or tigecycline. For isolates with vancomycin MICs of 2 μg/ml, the MIC90 values were 2 μg/ml for teicoplanin, 0.5 μg/ml for daptomycin, and 0.5 μg/ml for tigecycline. Those values were four- to eight-fold higher than those among isolates with vancomycin MICs of 0.5 μg/ml (2, 0.06, and 0.12 μg/ml, respectively). Of the nine MRSA isolates exhibiting non-susceptibility to vancomycin (n = 6), teicoplanin (n = 1), daptomycin (n = 2), or tigecycline (n = 1), all had different pulsotypes, indicating the absence of intra-hospital or inter-hospital spread. The presence of a high proportion of MRSA isolates with elevated MICs (2 μg/ml) and MIC creep of daptomycin might alert clinicians on the therapy for serious MRSA infections in Taiwan.

  12. Evolution of Staphylococcus aureus during human colonization and infection.

    Science.gov (United States)

    Fitzgerald, J Ross

    2014-01-01

    The diversification of bacterial pathogens during infection is central to their capacity to adapt to different anatomical niches, evade the host immune system, and overcome therapeutic challenges. For example, antimicrobial treatment may fail due to the development of resistance during infection, which is often accompanied by transition to a less virulent state during chronic, persistent infection. In this review, the adaptation of the major human pathogen Staphylococcus aureus to its host environment during infection will be discussed, particularly in the context of new sequencing technologies which have opened a gateway towards understanding of the molecular processes underlying those adaptations. We now have the capacity to address previously intractable questions regarding bacterial diversification during infection which will ultimately lead to enhanced understanding of pathogenesis and the nature of epidemics, and will inform the design of effective therapeutic measures.

  13. Antimicrobial Peptides

    Directory of Open Access Journals (Sweden)

    Ali Adem Bahar

    2013-11-01

    Full Text Available 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.

  14. Antimicrobial screening of Mnium stellare

    Directory of Open Access Journals (Sweden)

    Kerem Canli

    2015-06-01

    Full Text Available Many plants contain active substances that are known to be effective in both enhancing the wound healing process and lowering the incidence of wound infections. Previous studies have shown that bryophytes produce a variety of secondary metabolites that present pharmaceutical activities including antimicrobial activity against various pathogenic bacteria and fungi. The aim of this study was to investigate the antimicrobial activity of Mnium stellare against 17 bacterial and 1 fungal strains. Our present study has shown that the ethanol extract of M. stellare has antimicrobial activity against several Gram positive and Gram negative microorganism tested, but its antimicrobial activity is notable especially against B. subtilis, S. typhimirium, S. aureus, S. carnosus, and S. epidermidis. These results are the very first report of the antimicrobial activity of M. stellare.

  15. Síntese e determinação da atividade antimicrobiana de derivados 5-nitro-2-tiofilidênicos frente a Staphylococcus aureus multi-resistente Synthesis and determination of antimicrobial activity of 5-nitro-2-thiophylidene derivatives against MRSA

    Directory of Open Access Journals (Sweden)

    Andrea Masunari

    2006-09-01

    Full Text Available O elevado nível de resistência que cepas de Staphylococcus aureus vêm apresentando aos antibióticos atualmente disponíveis caracteriza-se como grave problema em âmbito mundial e com consequências que beiram à fatalidade. Com a atenção voltada para este fenômeno, quatorze derivados 5-nitro-2-tiofilidênicos foram sintetizados e testados quanto à atividade antimicrobiana frente a cepas padrão (ATCC 25923 e multi-resistente (3SP/R33 de Staphylococcus aureus. Todos os compostos testados apresentaram excelente atividade bacteriostática e, alguns entre eles, atividade bactericida. A 5-nitro-2-tiofilideno-4-acetilbenzidrazida se mostrou como o composto mais ativo com concentração inibitória equivalente a 0,14 mg/mL. A partir dos resultados obtidos evidenciou-se o forte potencial de derivados 5-nitro-2-tiofilidênicos como possível alternativa para o desenvolvimento de novos fármacos com atividade antimicrobiana.Infection diseases caused by methicillin-resistant Staphylococcus aureus have been an increasing problem worldwide presenting significant morbidity and mortality rates. Thus, fourteen benzoic acid [(5-nitro-thiophen-2-yl-methylene]-hydrazides were designed, synthesized and tested against standard (ATCC 25923 and multidrug-resistant strains of Staphylococcus aureus. All compounds exhibited significant bacteriostatic activity and, in such cases, also bactericidal activity, especially the p-COCH3 derivative with MIC = 0.14 mg/mL. The results have demonstrated the potential of synthesized compounds as alternative to the development of selective antimicrobial agents.

  16. Efeitos da administração de vitamina E na infecção mamária e na contagem de células somáticas de cabras primíparas desafiadas experimentalmente com Staphylococcus aureus Effects of administration of vitamin E on mammary health and milk cell counts of first parturition goats experimentally challenged with Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    P.R.O. Paes

    2003-02-01

    Full Text Available O trabalho teve por objetivo estudar os efeitos da administração de vitamina E sobre a contagem de células somáticas e a infecção da glândula mamária de cabras primíparas desafiadas com a inoculação intramamária de Staphylococcus aureus ao 10º dia pós-parto. Vinte e oito animais foram divididos em quatro grupos, cada um composto por sete cabras primíparas da raça Saanen, como segue: grupo-controle, grupo de animais suplementados com vitamina E, grupo de animais desafiados com S.aureus inoculados na glândula mamária e grupo de animais suplementados com vitamina E e desafiados com S.aureus na glândula mamária. Na segunda e terceira semanas de lactação, a inoculação de S.aureus na glândula mamária permitiu a recuperação do microrganismo no leite e elevou a contagem de células somáticas (CCS. A liberação de S.aureus no leite ocorreu de maneira intermitente. Em animais suplementados com vitamina E, o desafio com S.aureus resultou em CCS mais baixa e menor número de microrganismos no leite. Sugere-se que a CCS possa ser utilizada para a detecção da mastite caprina, devendo-se utilizar contagens superiores a 1,0x10(6células/ml de leite como critério para a realização de exames microbiológicos.The objective of the present study was to evaluate the effects of administration of vitamin E on mammary health and milk cell counts of first parturition Saanen goats, experimentally challenged with intramammary inoculation of Staphylococcus aureus on the 10th day postpartum. Twenty-eight animals were distributed into four groups: control group, a group supplemented with vitamin E, a group inoculated with S.aureus and a group supplemented with vitamin E and inoculated with S.aureus. The results demonstrated that, after inoculation of S.aureus into the mammary gland, the microorganism was recovered from the milk, and the somatic cell count was increased. The recovery of S.aureus from milk was intermittent. The increase in

  17. The Damage Effect of MSL Antimicrobial Peptide on the Membrane of the Pseudomonas Aeruginosa and Staphylococcus Aureus%MSL抗菌肽对绿脓杆菌和金黄色葡萄球菌细胞膜的损伤作用研究

    Institute of Scientific and Technical Information of China (English)

    刘艳环; 李海涛; 朱言柱; 张润祥; 肖佳美; 苗利光

    2015-01-01

    The aim of this study was to find the target of the MSL microbial peptide through The damage effect of MSL antimicrobial peptide on the membrane of the pseudomonas aeruginosa and staphylococcus aureus .MSL antimicrobial peptide was added into pseudomonas aeruginosa (1 × 108/mL) and staphylococcus aureus(1 × 108/mL) solution ,respectively .The final concentration of the solution was 1 × MIC .The solution was cultured at 37℃ .The supernatant was centrifuged and collected at 0min ,10min ,20min ,30min ,40min ,50min ,60min ,120min ,180min , 240min .The protein concentration was determined .MSL antimicrobial peptide was added into pseudomonas aeruginosa (1 × 108/mL ) and staphylococcus aureus(1 × 108/mL) solution ,respectively .The final concentration of the solution was 1 × MIC .The bacterial was cultured at 37℃ for 60min .The bacterial structure was observed by transmission electron microscopy .The result showed that cytosol released from the pseudomonas aeruginosa and staphylococcus aureus after the interaction of MSL antimicrobial peptide .The result of the transmission electron mi-croscopy showed that the MSL damaged the membrane of the pseudomonas aeruginosa and staphylococcus aureus ,electron density in the intracy-toplasm is decreased .Chromatin assemble .At the worst condition ,the structure of the membrane of the bacterial .It indicates that MSL damges the membrane of the G+ and G- bacterial and confirm that the membrane of the bacterial is the target of the MSL .%通过MSL抗菌肽(MSL )对细菌细胞膜的损伤作用研究,确定该抗菌肽的作用靶点。在1×108个/mL的绿脓杆菌和金黄色葡萄球菌悬液中,分别加入MSL至终浓度为1× MIC ,37℃保温孵育,分别于0min、10min、20min、30min、40min、50min、60min、120min、180min、240min离心收集上清液,检测各时间点蛋白浓度,分析蛋白浓度变化规律;分别在对数生长期的金黄色葡萄球菌和绿脓杆菌悬

  18. Comparative Antimicrobial Activities of Aerosolized Sodium Hypochlorite, Chlorine Dioxide, and Electrochemically Activated Solutions Evaluated Using a Novel Standardized Assay

    Science.gov (United States)

    Thorn, R. M. S.; Robinson, G. M.

    2013-01-01

    The main aim of this study was to develop a standardized experimental assay to enable differential antimicrobial comparisons of test biocidal aerosols. This study represents the first chlorine-matched comparative assessment of the antimicrobial activities of aerosolized sodium hypochlorite, chlorine dioxide, and electrochemically activated solution (ECAS) to determine their relative abilities to decontaminate various surface-associated health care-relevant microbial challenges. Standard microbiological challenges were developed by surface-associating typed Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis spores, or a clinical methicillin-resistant S. aureus (MRSA) strain on stainless steel, polypropylene, or fabric. All test coupons were subjected to 20-min biocidal aerosols of chlorine-matched (100 ppm) sodium hypochlorite, chlorine dioxide, or ECAS within a standard aerosolization chamber using a commercial humidifier under defined conditions. Biocidal treatment type and material surface had a significant effect on the number of microorganisms recovered from various material surfaces following treatment exposure. Under the conditions of the assay, the order of antimicrobial efficacy of biocidal aerosol treatment was as follows: ECAS > chlorine dioxide > sodium hypochlorite. For all biocides, greater antimicrobial reductions were seen when treating stainless steel and fabric than when treating plastic-associated microorganisms. The experimental fogging system and assay protocol designed within this study were shown capable of differentiating the comparative efficacies of multiple chlorine-matched biocidal aerosols against a spectrum of target organisms on a range of test surface materials and would be appropriate for testing other biocidal aerosol treatments or material surfaces. PMID:23459480

  19. Prevalence and resistance of commensal Staphylococcus aureus, including meticillin-resistant S aureus, in nine European countries: a cross-sectional study.

    NARCIS (Netherlands)

    Heijer, C.D.J. den; Bijnen, E.M.E. van; Paget, W.J.; Pringle, M.; Goossen, H.; Bruggeman, C.A.; Schellevis, F.G.; Stobberingh, E.E.

    2013-01-01

    Background: Information about the prevalence of Staphylococcus aureus resistance to antimicrobial drugs has mainly been obtained from invasive strains, although the commensal microbiota is thought to be an important reservoir of resistance. We aimed to compare the prevalence of nasal S aureus carria

  20. Prevalence and resistance of commensal Staphylococcus aureus, including meticillin-resistant S aureus, in nine European countries: a cross-sectional study

    NARCIS (Netherlands)

    Heijer, C.D. den; Bijnen, E.M. van; Paget, W.J.; Pringle, M.; Goossens, H.; Bruggeman, C.A.; Schellevis, F.G.; Stobberingh, E.E.

    2013-01-01

    BACKGROUND: Information about the prevalence of Staphylococcus aureus resistance to antimicrobial drugs has mainly been obtained from invasive strains, although the commensal microbiota is thought to be an important reservoir of resistance. We aimed to compare the prevalence of nasal S aureus carria

  1. Toxin genes detection and antimicrobial susceptibility test of Staphylococcus aureus isolated from retail chicken in Shaanxi Province%陕西省市售鸡肉中金黄色葡萄球菌的毒力基因及其药敏检测

    Institute of Scientific and Technical Information of China (English)

    徐本锦; 张伟松; 王新; 杨保伟; 席美丽; 夏效东; 孟江洪; 李新平

    2012-01-01

    To investigate the prevalence of toxin genes and antimicrobial profiles of Staphylococcus aureus (S. aureus) strains isolated from retail chicken in Shaanxi Province , a total of 122 S . aureus isolates from retail chicken were tested for the prevalence of nine enterotoxin genes and four exotoxin genes by polymerase chain reaction , and tested for antimicrobial susceptibility with 14 antibiotics by the agar dilution method . In the 122 strains of S. aureus, 59 .84% were positive for one or more toxin genes . The 25 .41% of the isolates harbored pvl gene, 51 .64% harbored one or more ses genes, sej (37 .70% ) was the most common pattern , and 4 .92% were positive for mecA gene. None of the isolates harbored see, seg, sei, ets or tsst-1 genes . A total of 20 toxin gene profiles were obtained , and sej (21 .31% ) was the most common profile , following by pvl (8 .20% ) , sej+pvl (4 .92% ), seh+sej+pvl (3 .28% ) and seh+pvl (3 .28% ) . Of these S. aureus isolates , 100 .0% were resistant to at least one antimicrobial , and 88.52% to three or more antimicrobials . Resistance was most frequently observed on erythromycin (87. 70% ), following by trimethoprim/siilfamethoxazole (81.97%), tetracycline (67.21% ), amikacin (59.02%), ciprofloxacin(53 .28% ), oxacillin (52.46% ) and amoxicil-lin/clavulanic acid (40 .16% ) . While significantly fewer isolates were resistant to ampicillin (32 .79% ), chlorampheni-col (27 .05% ) , gentamicin (20 .49% ), cefoxitin (13 .11% ) and cefoperazone (2 .46%). None of the; isolates was resistant to vancomycin . These findings indicated that many S. aureus i-solates from retail chicken in Shaanxi Province harbored multiple toxin genes and exhibited multiple antimicrobial resistances . The presence of S. aureus strains and methicillin-resistant S. aureus (MRSA) in retail chicken poses a potential threat to consumer health , so relevant regulation should be established to strengthen hygiene management of the chicken products .%目的

  2. Transmission of methicillin-resistant Staphylococcus aureus from food production animals to humans: a review

    NARCIS (Netherlands)

    Broens, E.M.; Cleef, van B.A.G.L.; Graat, E.A.M.; Kluytmans, J.A.J.W.

    2008-01-01

    International surveillance of antimicrobial use in food animal production shows that methicillinresistant Staphylococcus aureus (MRSA), traditionally a human pathogen associated with hospitals, has emerged in the community and animals. Since 1961, MRSA has been causing human infections in hospitals

  3. Pseudomonas aeruginosa Alginate Overproduction Promotes Coexistence with Staphylococcus aureus in a Model of Cystic Fibrosis Respiratory Infection.

    Science.gov (United States)

    Limoli, Dominique H; Whitfield, Gregory B; Kitao, Tomoe; Ivey, Melissa L; Davis, Michael R; Grahl, Nora; Hogan, Deborah A; Rahme, Laurence G; Howell, P Lynne; O'Toole, George A; Goldberg, Joanna B

    2017-03-21

    While complex intra- and interspecies microbial community dynamics are apparent during chronic infections and likely alter patient health outcomes, our understanding of these interactions is currently limited. For example, Pseudomonas aeruginosa and Staphylococcus aureus are often found to coinfect the lungs of patients with cystic fibrosis (CF), yet these organisms compete under laboratory conditions. Recent observations that coinfection correlates with decreased health outcomes necessitate we develop a greater understanding of these interbacterial interactions. In this study, we tested the hypothesis that P. aeruginosa and/or S. aureus adopts phenotypes that allow coexistence during infection. We compared competitive interactions of P. aeruginosa and S. aureus isolates from mono- or coinfected CF patients employing in vitro coculture models. P. aeruginosa isolates from monoinfected patients were more competitive toward S. aureus than P. aeruginosa isolates from coinfected patients. We also observed that the least competitive P. aeruginosa isolates possessed a mucoid phenotype. Mucoidy occurs upon constitutive activation of the sigma factor AlgT/U, which regulates synthesis of the polysaccharide alginate and dozens of other secreted factors, including some previously described to kill S. aureus Here, we show that production of alginate in mucoid strains is sufficient to inhibit anti-S. aureus activity independent of activation of the AlgT regulon. Alginate reduces production of siderophores, 2-heptyl-4-hydroxyquinolone-N-oxide (HQNO), and rhamnolipids-each required for efficient killing of S. aureus These studies demonstrate alginate overproduction may be an important factor driving P. aeruginosa coinfection with S. aureusIMPORTANCE Numerous deep-sequencing studies have revealed the microbial communities present during respiratory infections in cystic fibrosis (CF) patients are diverse, complex, and dynamic. We now face the challenge of determining

  4. Expression of acute phase proteins and inflammatory cytokines in mouse mammary gland following Staphylococcus aureus challenge and in response to milk accumulation

    DEFF Research Database (Denmark)

    Nazemi, Sasan; Aalbæk, Bent; Kjelgaard-Hansen, Mads

    2014-01-01

    We used a mouse model of pathogenic (Staphylococcus aureus) and non-pathogenic (teat sealing) mammary inflammation to investigate mRNA expression of several inflammatory cytokines and acute phase proteins (APP) in mammary tissue and liver, and the appearance of some of these factors in plasma...... in combination might provide a tool for diagnostic discrimination between mastitis caused by pathogenic invasion and milk accumulation, and hence allow for better targeting of antibiotic therapy. In comparison with mammary expression, expression of cytokines in liver tissue was up-regulated to a similar...... or lesser extent, whilst expression of APP was up-regulated to a much greater extent. The first appearance of increased cytokine and APP concentrations in plasma and of milk amyloid A (MAA) in milk occurred in advance of the measurable up-regulation of expression, hence their origin cannot be stated...

  5. Evaluation of fusidic acid in therapy of experimental Staphylococcus aureus meningitis

    DEFF Research Database (Denmark)

    Østergaard, Christian; Yieng-Kow, Runa Vavia; Knudsen, Jenny Dahl;

    2003-01-01

    Combination therapy that includes fusidic acid, an antimicrobial agent highly active against staphylococci, has been recommended in the treatment of patients with Staphylococcus aureus meningitis. The aim of this study was to evaluate the pharmacokinetic, CSF bactericidal and anti-inflammatory pr......Combination therapy that includes fusidic acid, an antimicrobial agent highly active against staphylococci, has been recommended in the treatment of patients with Staphylococcus aureus meningitis. The aim of this study was to evaluate the pharmacokinetic, CSF bactericidal and anti...

  6. Synthesis and antibacterial evaluation of a novel series of synthetic phenylthiazole compounds against methicillin-resistant Staphylococcus aureus (MRSA).

    Science.gov (United States)

    Mohammad, Haroon; Reddy, P V Narasimha; Monteleone, Dennis; Mayhoub, Abdelrahman S; Cushman, Mark; Seleem, Mohamed N

    2015-04-13

    Methicillin-resistant Staphylococcus aureus infections are a significant global health challenge in part due to the emergence of strains exhibiting resistance to nearly all classes of antibiotics. This underscores the urgent need for the rapid development of novel antimicrobials to circumvent this burgeoning problem. Previously, whole-cell screening of a library of 2,5-disubstituted thiazole compounds revealed a lead compound exhibiting potent antimicrobial activity against MRSA. The present study, conducting a more rigorous analysis of the structure-activity relationship of this compound, reveals a nonpolar, hydrophobic functional group is favored at thiazole-C2 and an ethylidenehydrazine-1-carboximidamide moiety is necessary at C5 for the compound to possess activity against MRSA. Furthermore, the MTS assay confirmed analogs 5, 22d, and 25 exhibited an improved toxicity profile (not toxic up to 40 μg/mL to mammalian cells) over the lead 1. Analysis with human liver microsomes revealed compound 5 was more metabolically stable compared to the lead compound (greater than eight-fold improvement in the half-life in human liver microsomes). Collectively the results presented demonstrate the novel thiazole derivatives synthesized warrant further exploration for potential use as future antimicrobial agents for the treatment of multidrug-resistant S. aureus infections.

  7. Dissimilar Regulation of Antimicrobial Proteins in the Midgut of Spodoptera exigua Larvae Challenged with Bacillus thuringiensis Toxins or Baculovirus

    Science.gov (United States)

    Crava, Cristina M.; Jakubowska, Agata K.; Escriche, Baltasar; Herrero, Salvador; Bel, Yolanda

    2015-01-01

    Antimicrobial peptides (AMPs) and lysozymes are the main effectors of the insect immune system, and they are involved in both local and systemic responses. Among local responses, midgut immune reaction plays an important role in fighting pathogens that reach the insect body through the oral route, as do many microorganisms used in pest control. Under this point of view, understanding how insects defend themselves locally during the first phases of infections caused by food-borne pathogens is important to further improve microbial control strategies. In the present study, we analyzed the transcriptional response of AMPs and lysozymes in the midgut of Spodoptera exigua (Lepidoptera: Noctuidae), a polyphagous pest that is commonly controlled by products based on Bacillus thuringiensis (Bt) or baculovirus. First, we comprehensively characterized the transcripts encoding AMPs and lysozymes expressed in S. exigua larval midgut, identifying 35 transcripts that represent the S. exigua arsenal against microbial infection. Secondly, we analyzed their expression in the midgut after ingestion of sub-lethal doses of two different pore-forming B. thuringiensis toxins, Cry1Ca and Vip3Aa, and the S. exigua nucleopolyhedrovirus (SeMNPV). We observed that both Bt toxins triggered a similar, wide and in some cases high transcriptional activation of genes encoding AMPs and lysozymes, which was not reflected in the activation of the classical systemic immune-marker phenoloxidase in hemolymph. Baculovirus ingestion resulted in the opposed reaction: Almost all transcripts coding for AMPs and lysozymes were down-regulated or not induced 96 hours post infection. Our results shed light on midgut response to different virulence factors or pathogens used nowadays as microbial control agents and point out the importance of the midgut immune response contribution to the larval immunity. PMID:25993013

  8. Dissimilar Regulation of Antimicrobial Proteins in the Midgut of Spodoptera exigua Larvae Challenged with Bacillus thuringiensis Toxins or Baculovirus.

    Science.gov (United States)

    Crava, Cristina M; Jakubowska, Agata K; Escriche, Baltasar; Herrero, Salvador; Bel, Yolanda

    2015-01-01

    Antimicrobial peptides (AMPs) and lysozymes are the main effectors of the insect immune system, and they are involved in both local and systemic responses. Among local responses, midgut immune reaction plays an important role in fighting pathogens that reach the insect body through the oral route, as do many microorganisms used in pest control. Under this point of view, understanding how insects defend themselves locally during the first phases of infections caused by food-borne pathogens is important to further improve microbial control strategies. In the present study, we analyzed the transcriptional response of AMPs and lysozymes in the midgut of Spodoptera exigua (Lepidoptera: Noctuidae), a polyphagous pest that is commonly controlled by products based on Bacillus thuringiensis (Bt) or baculovirus. First, we comprehensively characterized the transcripts encoding AMPs and lysozymes expressed in S. exigua larval midgut, identifying 35 transcripts that represent the S. exigua arsenal against microbial infection. Secondly, we analyzed their expression in the midgut after ingestion of sub-lethal doses of two different pore-forming B. thuringiensis toxins, Cry1Ca and Vip3Aa, and the S. exigua nucleopolyhedrovirus (SeMNPV). We observed that both Bt toxins triggered a similar, wide and in some cases high transcriptional activation of genes encoding AMPs and lysozymes, which was not reflected in the activation of the classical systemic immune-marker phenoloxidase in hemolymph. Baculovirus ingestion resulted in the opposed reaction: Almost all transcripts coding for AMPs and lysozymes were down-regulated or not induced 96 hours post infection. Our results shed light on midgut response to different virulence factors or pathogens used nowadays as microbial control agents and point out the importance of the midgut immune response contribution to the larval immunity.

  9. Dissimilar Regulation of Antimicrobial Proteins in the Midgut of Spodoptera exigua Larvae Challenged with Bacillus thuringiensis Toxins or Baculovirus.

    Directory of Open Access Journals (Sweden)

    Cristina M Crava

    Full Text Available Antimicrobial peptides (AMPs and lysozymes are the main effectors of the insect immune system, and they are involved in both local and systemic responses. Among local responses, midgut immune reaction plays an important role in fighting pathogens that reach the insect body through the oral route, as do many microorganisms used in pest control. Under this point of view, understanding how insects defend themselves locally during the first phases of infections caused by food-borne pathogens is important to further improve microbial control strategies. In the present study, we analyzed the transcriptional response of AMPs and lysozymes in the midgut of Spodoptera exigua (Lepidoptera: Noctuidae, a polyphagous pest that is commonly controlled by products based on Bacillus thuringiensis (Bt or baculovirus. First, we comprehensively characterized the transcripts encoding AMPs and lysozymes expressed in S. exigua larval midgut, identifying 35 transcripts that represent the S. exigua arsenal against microbial infection. Secondly, we analyzed their expression in the midgut after ingestion of sub-lethal doses of two different pore-forming B. thuringiensis toxins, Cry1Ca and Vip3Aa, and the S. exigua nucleopolyhedrovirus (SeMNPV. We observed that both Bt toxins triggered a similar, wide and in some cases high transcriptional activation of genes encoding AMPs and lysozymes, which was not reflected in the activation of the classical systemic immune-marker phenoloxidase in hemolymph. Baculovirus ingestion resulted in the opposed reaction: Almost all transcripts coding for AMPs and lysozymes were down-regulated or not induced 96 hours post infection. Our results shed light on midgut response to different virulence factors or pathogens used nowadays as microbial control agents and point out the importance of the midgut immune response contribution to the larval immunity.

  10. Structural and functional characterization of Staphylococcus aureus dihydrodipicolinate synthase.

    Science.gov (United States)

    Girish, Tavarekere S; Sharma, Eshita; Gopal, B

    2008-08-20

    Lysine biosynthesis is crucial for cell-wall formation in bacteria. Enzymes involved in lysine biosynthesis are thus potential targets for anti-microbial therapeutics. Dihydrodipicolinate synthase (DHDPS) catalyzes the first step of this pathway. Unlike its homologues, Staphylococcus aureus DHDPS is a dimer both in solution and in the crystal and is not feedback inhibited by lysine. The crystal structure of S. aureus DHDPS in the free and substrate bound forms provides a structural rationale for its catalytic mechanism. The structure also reveals unique conformational features of the S. aureus enzyme that could be crucial for the design of specific non-competitive inhibitors.

  11. The Effect of Essential Oils on Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Seda Ozdikmenli

    2014-05-01

    Full Text Available Diseases caused by Staphylococcus aureus are widespread through the world in spite of developing technology. S. aureus is an important pathogen causing food intoxications besides hospital infections by its antibiotic resistant strains. Nowadays, there has been worldwide increasing concern on usage of natural products to control microorganisms. One of these natural products is essential oils. They are produced from plants especially from spices and composed of many components and volatiles. This review summarizes informative literature on essential oils and their mode of antimicrobial action. In addition, current knowledge on in vitro researches on antibacterial activity of essential oils and food applications to control S. aureus has been discussed.

  12. Osteomyelitis: a current challenge

    Directory of Open Access Journals (Sweden)

    Luciana Souza Jorge

    2010-06-01

    Full Text Available Over the last 30 years, the pathogenesis of osteomyelitis has almost been totally elucidated, and many factors responsible for the persistence of this infection have been identified. Numerous antimicrobial agents with distinct spectrums of action, pharmacokinetics, and pharmacodynamics have been used in its treatment. Surgical techniques, including muscle grafts, the Ilizarov technique, and antibiotic bone cements, have been applied. However, bone infections are still a challenge. Despite the importance of isolation and identification of microorganisms to determine the antimicrobial treatment of bone infections, there are few systematic national studies about the etiological profile of these diseases. This article describes the current knowledge of osteomyelitis and summarizes published national data based on the experience of different Orthopedic and Traumatology Services. In general, S. aureus was described as an important etiological agent; however, the difference in design of national studies makes a comparison between the prevalence of bone infection, the associated risk factors, and the different therapeutic approaches difficult. In conclusion, effort is necessary in order to stimulate systematic national studies in different Orthopedics and Traumatology Services to obtain a better consensus on preventive measures and therapies of bone infections.

  13. Antimicrobial resistance in bacteria from horses: Epidemiology of antimicrobial resistance.

    Science.gov (United States)

    Maddox, T W; Clegg, P D; Williams, N J; Pinchbeck, G L

    2015-11-01

    Antimicrobial resistance poses a significant threat to the continued successful use of antimicrobial agents for the treatment of bacterial infections. While the epidemiology of antimicrobial resistance in bacteria from man has been studied extensively, less work has been undertaken in companion animals, particularly horses. Methicillin-resistant Staphylococcus aureus has been identified as a cause of infections, with a low prevalence of nasal carriage by horses in the community but higher for hospitalised horses. Molecular characterisation has shown methicillin-resistant Staphylococcus aureus strains either to be predominantly of types associated with horses or of sequence type ST398. Antimicrobial-resistant Escherichia coli (including multidrug-resistant and extended spectrum β-lactamase-producing isolates) have caused infections and been documented in faecal carriage by horses, with many significant resistance mechanisms identified. More sporadic reports and molecular characterisation exist for resistance in other bacteria such as enterococci, Salmonella, Acinetobacter and Pseudomonas species. Limited work has been undertaken evaluating risk factors and much of the epidemiology of antimicrobial resistance in bacteria from horses remains to be determined.

  14. Staphylococcus aureus and Pregnancy

    Science.gov (United States)

    Staphylococcus aureus and Pregnancy In every pregnancy, a woman starts out with a 3-5% chance of having a ... This sheet talks about whether exposure to staphylococcus aureus may increase the risk for birth defects over ...

  15. Triple-acting Peptidoglycan hydrolase treatment for drug-resistant and intracellular Staphylococcus aureus

    Science.gov (United States)

    Multi-drug resistant bacteria are a persistent problem in modern health care, food safety and animal health. There is a need for new antimicrobials to replace over-used conventional antibiotics. Staphylococcus aureus (S. aureus) is a notorious pathogen for both animal and human health with multi-d...

  16. Antimicrobial activities of squalamine mimics.

    Science.gov (United States)

    Kikuchi, K; Bernard, E M; Sadownik, A; Regen, S L; Armstrong, D

    1997-07-01

    We investigated the antimicrobial properties of compounds with structural features that were designed to mimic those of squalamine, an antibiotic isolated from the stomach of the dogfish shark. The mimics, like squalamine, are sterol-polyamine conjugates. Unlike squalamine, the mimics were simple to prepare, at high yield, from readily available starting materials. Several squalamine mimics showed activity against gram-negative rods, gram-positive cocci including methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus faecium, and fungi. Some had little or no hemolytic activity. The hydrophobicity of the sterol backbone and the length and the cationic charge of the side chains appeared to be critical determinants of activity. One of the squalamine mimics, SM-7, was bactericidal against Escherichia coli, Pseudomonas aeruginosa, and S. aureus; its activity was decreased by divalent or monovalent cations and by bovine serum albumin. Subinhibitory concentrations of SM-7 markedly enhanced the antimicrobial activity of rifampin against gram-negative rods. These results suggest that the compounds may disrupt an outer membrane of gram-negative rods. Squalamine mimics are a new class of broad-spectrum antimicrobial agents. The antagonism of their activity by serum and albumin and their hemolytic properties may limit their use as systemic agents. The squalamine mimics, because of their potencies, broad spectra of antimicrobial activity, and potential for systemic toxicity, appear to be good candidates for development as topical antimicrobial agents.

  17. Neutrophil-mediated phagocytosis of Staphylococcus aureus

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    Jos A.G. Van Strijp

    2014-09-01

    Full Text Available For invading staphylococci, phagocytosis an killing bij human neutrophils is the biggest threat. Neutrophils are the only cells that can effectively kill staphylococci by engulfment and subsequent bombardment with proteases, amidases, antimicrobial peptides and proteins in concert with reactive oxygen species that are generated during the metabolic burst.Both complement and antibodies are crucial for effective uptake and neutrophil activation. S. aureus is not an innocent bystander in this process. It actively secretes several proteins to impair every single step in this process from receptor modulation, to complement inhibition to neutrophil lysis to protease, antimicrobial peptide inhibition and resistance to reactive oxygen species. For the design of future novel antimicrobial strategies: therapeutic antibodies, vaccines, novel antibiotics, all this should be taken into account. Still the best way to treat diseases is to help to enhance the natural defence mechanism that are already in place.

  18. ANTIMICROBIAL ACTION OF THE LEAF EXTRACT OF MORINGA OLEIFERA LAM.

    OpenAIRE

    Pal, Saroj K.; Mukherjee, Pulok K.; Saha, Kakali; Pal, M.; Saha, B.P

    1995-01-01

    The ethnolic extract of the leaves of Moringa oleifera Lam. (Fam. Moringaceae) was tested for antimicrobial activities against Gram Positive – Bacillus cereus, Bacillus subtilis Staphylococcus aureus, Sarcina lutea: Gram negative – Escherichia coli and Acid fast Mycobacterium phlei. Significant antimicrobial activity of the extract was found in this study.

  19. Antimicrobial action of the leaf extract of moringa oleifera lam.

    Science.gov (United States)

    Pal, S K; Mukherjee, P K; Saha, K; Pal, M; Saha, B P

    1995-01-01

    The ethnolic extract of the leaves of Moringa oleifera Lam. (Fam. Moringaceae) was tested for antimicrobial activities against Gram Positive - Bacillus cereus, Bacillus subtilis Staphylococcus aureus, Sarcina lutea: Gram negative - Escherichia coli and Acid fast Mycobacterium phlei. Significant antimicrobial activity of the extract was found in this study.

  20. Antibacterial activity of THAM Trisphenylguanide against methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Weaver, Alan J; Shepard, Joyce B; Wilkinson, Royce A; Watkins, Robert L; Walton, Sarah K; Radke, Amanda R; Wright, Thomas J; Awel, Milat B; Cooper, Catherine; Erikson, Elizabeth; Labib, Mohamed E; Voyich, Jovanka M; Teintze, Martin

    2014-01-01

    This study investigated the potential antibacterial activity of three series of compounds synthesized from 12 linear and branched polyamines with 2-8 amino groups, which were substituted to produce the corresponding guanides, biguanides, or phenylguanides, against Acinetobacter baumannii, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. Antibacterial activity was measured for each compound by determining the minimum inhibitory concentration against the bacteria, and the toxicity towards mammalian cells was determined. The most effective compound, THAM trisphenylguanide, was studied in time-to-kill and cytoplasmic leakage assays against methicillin-resistant Staphylococcus aureus (MRSA, USA300) in comparison to chlorhexidine. Preliminary toxicity and MRSA challenge studies in mice were also conducted on this compound. THAM trisphenylguanide showed significant antibacterial activity (MIC ∼1 mg/L) and selectivity against MRSA relative to all the other bacteria examined. In time-to-kill assays it showed increased antimicrobial activity against MRSA versus chlorhexidine. It induced leakage of cytoplasmic content at concentrations that did not reduce cell viability, suggesting the mechanism of action may involve membrane disruption. Using an intraperitoneal mouse model of invasive MRSA disease, THAM trisphenylguanide reduced bacterial burden locally and in deeper tissues. This study has identified a novel guanide compound with selective microbicidal activity against Staphylococcus aureus, including a methicillin-resistant (MRSA) strain.

  1. Antibacterial activity of THAM Trisphenylguanide against methicillin-resistant Staphylococcus aureus.

    Directory of Open Access Journals (Sweden)

    Alan J Weaver

    Full Text Available This study investigated the potential antibacterial activity of three series of compounds synthesized from 12 linear and branched polyamines with 2-8 amino groups, which were substituted to produce the corresponding guanides, biguanides, or phenylguanides, against Acinetobacter baumannii, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. Antibacterial activity was measured for each compound by determining the minimum inhibitory concentration against the bacteria, and the toxicity towards mammalian cells was determined. The most effective compound, THAM trisphenylguanide, was studied in time-to-kill and cytoplasmic leakage assays against methicillin-resistant Staphylococcus aureus (MRSA, USA300 in comparison to chlorhexidine. Preliminary toxicity and MRSA challenge studies in mice were also conducted on this compound. THAM trisphenylguanide showed significant antibacterial activity (MIC ∼1 mg/L and selectivity against MRSA relative to all the other bacteria examined. In time-to-kill assays it showed increased antimicrobial activity against MRSA versus chlorhexidine. It induced leakage of cytoplasmic content at concentrations that did not reduce cell viability, suggesting the mechanism of action may involve membrane disruption. Using an intraperitoneal mouse model of invasive MRSA disease, THAM trisphenylguanide reduced bacterial burden locally and in deeper tissues. This study has identified a novel guanide compound with selective microbicidal activity against Staphylococcus aureus, including a methicillin-resistant (MRSA strain.

  2. Antimicrobial resistance and homologκ analκsis of Staphκloccocus aureus isolated from neo-nates with skin infections%母婴同室新生儿皮肤感染金黄色葡萄球菌耐药性研究及同源性分析

    Institute of Scientific and Technical Information of China (English)

    宋风丽; 马秀华; 石鑫; 史伟; 王春霞; 刘盈; 马琳

    2014-01-01

    目的:了解母婴同室新生儿皮肤感染金葡菌耐药状况,探讨其同源性,为指导临床治疗和预防控制感染提供依据。方法对北京市大兴区人民医院皮肤感染的新生儿皮损分泌物进行细菌培养、鉴定及药敏试验,应用脉冲场凝胶电泳方法进行基因分型。结果新生儿皮肤感染率为2.1%;金葡菌13株,占30.2%;头孢唑林、阿莫西林或克拉维酸及哌拉西林或他唑巴坦对金葡菌具有良好的抗菌活性。脉冲场凝胶电泳示H组与I组图谱完全相同。结论治疗新生儿金葡菌所致皮肤感染首选头孢类抗生素、阿莫西林或克拉维酸、哌拉西林或他唑巴坦;预防和控制其感染,须加强对新生儿皮肤和脐部的护理。%Objective To investigate the antimicrobial resistance and homology analysis of Staphylococcus aureus ( S. aureus) isolated from with skin infections, thus to search for appropriate process to treat/prevent these skin disea-ses. Method Secretions of skin lesions from newborns with skin infections delivered in Obstetrics Department of Beijing Daxing People’s Hospital from Jan. 2012 to Jun. 2012 were collected,cultured and drug sensitivity test. Antibiotic resistances of S. aureus were determined. The genotype was detected with pulsed gel electrophoresis. Result Of 13 S. aureus isolated, the incidence was 30. 2%. Impetigo is the main disease of skin infection. S. au-reus was sensitive to cefazolin, amoxicillin/clavulanic acid and piperacillin/tazobactam. PFGE pattern of 13 strains showed 10 types, two type H and two type I which have the same pattern respectively. Conclusion The results sug-gest that effective clinical medication for skin and soft tissue infections caused by S. aureus are cefazolin, amoxicil-lin/clavulanic acid and piperacillin /tazobactam. It is important to disinfect all things the neonates may contact for preventing neonate infections caused by S. aureus.

  3. 抗菌肽BuforinⅡ衍生物对金黄色葡萄球菌细胞膜作用机制的研究%The Action Mechanism of Two Analogues of the Antimicrobial Peptide Buforin Ⅱ on Staphylococcus aureus Membrane

    Institute of Scientific and Technical Information of China (English)

    郝刚; 乐国伟; 施用晖

    2013-01-01

    In this paper,the action mechanism of BF2-A/B,two analogues of antimicrobial peptide Buforin Ⅱ,on Staphylococcus aureus membrane had been researched.The results of FACS-can analysis implied that BF2-A/B did not induce the influx of PI into the S.aureus cells.The rate of positive cells stained by fluorescent probe after BF2-B treatment was slightly higher than that of BF2-A.These electron micrographs showed that after 20 min of treatment by BF2-A,S.aureus cells still retained the plasma membrane integrality; however,BF2-B could cause some slight leakages of cellular cytoplasmic contents.The results of FACS analysis displayed that both the peptides could penetrate the cells,and BF2-B penetrated the cells more efficiently.The visualization of cofoocal microscopy proved that FITC-labeled BF2-A and BF2-B penetrated the bacterial cell membrane and accumulated in the cytoplasm of the cell immediately.The results of research demonstrated that BF2-A/B didn't destroy the cell membrane of G+ bacteria,and then exert the antimicrobial activity after influx into cytoplasm.BF2-B slightly disturbed cell membrane causing influx of PI and leakage of cytoplasmic contents during peptide crossing phospholipids bilayer.Meanwhile,the cell-penetrating efficiency of BF2-B was accordingly enhanced,which caused that BF2-B displayed more excellent antimicrobial activity to S.aureus.%为研究抗菌肽BuforinⅡ的衍生物BF2-A/B对金黄色葡萄球菌细胞膜的作用机制,用流式细胞仪分析BF2-A/B对金黄色葡萄球菌细胞膜通透性的影响,以及穿膜效率,用透射电镜观察细胞膜的完整性,激光共聚焦显微镜观察抗菌肽在胞质内的积累.结果显示,BF2-A/B都不显著引起PI流入细胞质内,但BF2-B处理的细胞PI着染阳性比例高于BF2-A.BF2-A处理20 min后的细胞膜依然完整,而BF2-B能使胞质内容物轻微泄漏.抗菌肽BF2-A/B都能显著穿透细胞膜,并且BF2-B的穿膜效率高于BF2-A.同时荧光共聚焦显微镜也

  4. Antimicrobial peptides from the hemolymph of the prawn Macrobrachium rosenbergii

    Directory of Open Access Journals (Sweden)

    Samuthirapandian Ravichandran

    2010-03-01

    Full Text Available The study was carried out to find the antimicrobial activity of hemolymph of Macrobrachium rosenbergii and to evaluate the antimicrobial compounds. The highest inhibition against Staphylococcus aureus, Lactobacillus vulgaris and Klebsiella pneumonia (12 mm and antifungal activity was observed only against Fusarium moniliforme (11 mm. Antimicrobial peptide was characterized in molecular size ranging from 22 to 91KDa with antimicrobial activity against various infectious pathogens. Hemolymph plays a vital role in the disease prevention in crustaceans and there is no report on antimicrobial activities of the prawn M. rosenbergii.

  5. Staphylococcus aureus toxins.

    Science.gov (United States)

    Otto, Michael

    2014-02-01

    Staphylococcus aureus is a dangerous pathogen that causes a variety of severe diseases. The virulence of S. aureus is defined by a large repertoire of virulence factors, among which secreted toxins play a preeminent role. Many S. aureus toxins damage biological membranes, leading to cell death. In particular, S. aureus produces potent hemolysins and leukotoxins. Among the latter, some were recently identified to lyse neutrophils after ingestion, representing an especially powerful weapon against bacterial elimination by innate host defense. Furthermore, S. aureus secretes many factors that inhibit the complement cascade or prevent recognition by host defenses. Several further toxins add to this multi-faceted program of S. aureus to evade elimination in the host. This review will give an overview over S. aureus toxins focusing on recent advances in our understanding of how leukotoxins work in receptor-mediated or receptor-independent fashions.

  6. Antimicrobial Pesticides

    Science.gov (United States)

    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 ...

  7. Threat of multidrug resistant Staphylococcus aureus in Western Nepal

    DEFF Research Database (Denmark)

    Bhatta, Dharm R.; Cavaco, Lina; Nath, Gopal;

    2015-01-01

    ObjectiveTo determine the prevalence of methicillin resistant Staphylococcus aureus (MRSA) and antimicrobial susceptibility patterns of the isolates from Manipal Teaching Hospital, Pokhara, Nepal. MethodsThis study was conducted over a period of 11 months (September 2012–August 2013) at the Manip...

  8. Efficacy of extended cefquinome treatment of clinical Staphylococcus aureus mastitis

    NARCIS (Netherlands)

    Swinkels, J. M.; Cox, P.; Schukken, Y. H.; Lam, T. J G M

    2013-01-01

    Clinical Staphylococcus aureus mastitis is difficult to cure. Extended antimicrobial treatment is often advocated as a practical approach to improve cure rates; however, scientific evidence of this hypothesis is lacking. A multi-centered, nonblinded, randomized, positive-controlled clinical trial wa

  9. Pharmacogenomics of antimicrobial agents.

    Science.gov (United States)

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

    2014-01-01

    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.

  10. Dissemination of methicillin-resistant Staphylococcus aureus SCCmec type IV and SCCmec type V epidemic clones in a tertiary hospital: challenge to infection control.

    Science.gov (United States)

    Dhawan, B; Rao, C; Udo, E E; Gadepalli, R; Vishnubhatla, S; Kapil, A

    2015-01-01

    Two-hundred MRSA strains from inpatients with healthcare-associated (HA) and 100 MRSA strains from outpatients with community-associated (CA) skin and soft tissue infections (SSTIs) were tested for antimicrobial susceptibility, staphylococcal cassette chromosome mec (SCCmec) typing, Panton-Valentine leucocidin (PVL) toxin, seh and arcA genes. Based on SCCmec typing, HA-MRSA isolates were further divided into HA-SCCmec I/II/III MRSA and HA-SCCmec IV/V MRSA, and CA-MRSA isolates into CA-SCCmec I/II/III MRSA and CA-SCCmec IV/V MRSA. SCCmec types were further characterized by pulsed-field gel electrophoresis, spa typing and multi-locus sequence typing. Seventy-five (37·5%) HA-MRSA isolates and 83/100 CA-MRSA isolates were SCCmec IV/V genotype. HA-SCCmec IV/V MRSA was associated with malignancy (P = 0·03) and bone fractures (P = 0·02) compared to CA-SCCmec IV/V MRSA. HA-SCCmec IV/V MRSA was associated with PVL gene carriage compared to HA-SCCmec I/II/III MRSA (P IV (EMRSA-15), ST772-MRSA-V, and ST36-MRSA-IV and ST239:EMRSA-I:III were the major clones identified. Our study documents the emergence of SCCmec IV and SCCmec V MRSA clones in an Indian hospital.

  11. Antimicrobial stewardship.

    Science.gov (United States)

    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.

  12. Antimicrobial resistance in India: A review

    OpenAIRE

    2013-01-01

    Antimicrobial resistance is an important concern for the public health authorities at global level. However, in developing countries like India, recent hospital and some community based data showed increase in burden of antimicrobial resistance. Research related to antimicrobial use, determinants and development of antimicrobial resistance, regional variation and interventional strategies according to the existing health care situation in each country is a big challenge. This paper discusses ...

  13. Staphylococcus aureus small colony variants in diabetic foot infections

    Directory of Open Access Journals (Sweden)

    Estrella Cervantes-García

    2015-03-01

    Full Text Available Background: Staphylococcus aureus (S. aureus is one of the major pathogens causing chronic infections. The ability of S. aureus to acquire resistance to a diverse range of antimicrobial compounds results in limited treatment options, particularly in methicillin-resistant S. aureus (MRSA. A mechanism by which S. aureus develops reduced susceptibility to antimicrobials is through the formation of small colony variants (SCVs. Infections by SCVs of S. aureus are an upcoming problem due to difficulties in laboratory diagnosis and resistance to antimicrobial therapy. Methods: A prospective study was performed on 120 patients diagnosed with both type 2 diabetes mellitus and infected diabetic foot ulcers. The study was carried out from July 2012 to December 2013 in Hospital General de Mexico. The samples were cultured in blood agar, mannitol salt agar, and MacConkey agar media, and incubated at 37°C in aerobic conditions. Results: We describe the first known cases of diabetic foot infections caused by MRSA-SCVs in patients diagnosed with type 2 diabetes mellitus and infected diabetic foot ulcers. In all of our cases, the patients had not received any form of gentamicin therapy. Conclusions: The antibiotic therapy commonly used in diabetic patients with infected diabetic foot ulcers fails in the case of MRSA-SCVs because the intracellular location protects S. aureus-SCVs from the host's defenses and also helps them resist antibiotics. The cases studied in this article add to the spectrum of persistent and relapsing infections attributed to MRSA-SCVs and emphasizes that these variants may also play a relevant role in diabetic foot infections.

  14. Staphylococcus aureus small colony variants in diabetic foot infections

    Science.gov (United States)

    Cervantes-García, Estrella; García-Gonzalez, Rafael; Reyes-Torres, Angélica; Resendiz-Albor, Aldo Arturo; Salazar-Schettino, Paz María

    2015-01-01

    Background Staphylococcus aureus (S. aureus) is one of the major pathogens causing chronic infections. The ability of S. aureus to acquire resistance to a diverse range of antimicrobial compounds results in limited treatment options, particularly in methicillin-resistant S. aureus (MRSA). A mechanism by which S. aureus develops reduced susceptibility to antimicrobials is through the formation of small colony variants (SCVs). Infections by SCVs of S. aureus are an upcoming problem due to difficulties in laboratory diagnosis and resistance to antimicrobial therapy. Methods A prospective study was performed on 120 patients diagnosed with both type 2 diabetes mellitus and infected diabetic foot ulcers. The study was carried out from July 2012 to December 2013 in Hospital General de Mexico. The samples were cultured in blood agar, mannitol salt agar, and MacConkey agar media, and incubated at 37°C in aerobic conditions. Results We describe the first known cases of diabetic foot infections caused by MRSA-SCVs in patients diagnosed with type 2 diabetes mellitus and infected diabetic foot ulcers. In all of our cases, the patients had not received any form of gentamicin therapy. Conclusions The antibiotic therapy commonly used in diabetic patients with infected diabetic foot ulcers fails in the case of MRSA-SCVs because the intracellular location protects S. aureus-SCVs from the host's defenses and also helps them resist antibiotics. The cases studied in this article add to the spectrum of persistent and relapsing infections attributed to MRSA-SCVs and emphasizes that these variants may also play a relevant role in diabetic foot infections. PMID:25787018

  15. Cateslytin, a chromogranin A derived peptide is active against Staphylococcus aureus and resistant to degradation by its proteases.

    Directory of Open Access Journals (Sweden)

    Rizwan Aslam

    Full Text Available Innate immunity involving antimicrobial peptides represents an integrated and highly effective system of molecular and cellular mechanisms that protects host against infections. One of the most frequent hospital-acquired pathogens, Staphylococcus aureus, capable of producing proteolytic enzymes, which can degrade the host defence agents and tissue components. Numerous antimicrobial peptides derived from chromogranins, are secreted by nervous, endocrine and immune cells during stress conditions. These kill microorganisms by their lytic effect at micromolar range, using a pore-forming mechanism against Gram-positive bacteria, filamentous fungi and yeasts. In this study, we tested antimicrobial activity of chromogranin A-derived peptides (catestatin and cateslytin against S. aureus and analysed S. aureus-mediated proteolysis of these peptides using HPLC, sequencing and MALDI-TOF mass spectrometry. Interestingly, this study is the first to demonstrate that cateslytin, the active domain of catestatin, is active against S. aureus and is interestingly resistant to degradation by S. aureus proteases.

  16. Synergistic effect of Thymbra spicata L. extracts with antibiotics against multidrug- resistant Staphylococcus aureus and Klebsiella pneumoniae strains

    Directory of Open Access Journals (Sweden)

    Mohammad F Haroun

    2016-11-01

    Conclusion: These results may indicate that T. spicata extracts potentiates the antimicrobial action of antibiotics, suggesting a possible utilization of this herb in combination therapy against emerging multidrug-resistance S. aureus and K. pneumoniae.

  17. Early oral switch therapy in low-risk Staphylococcus aureus bloodstream infection (SABATO) : Study protocol for a randomized controlled trial

    NARCIS (Netherlands)

    Kaasch, Achim J.; Fätkenheuer, Gerd; Prinz-Langenohl, Reinhild; Paulus, Ursula; Hellmich, Martin; Weiß, Verena; Jung, Norma; Rieg, Siegbert; Kern, Winfried V.; Seifert, Harald; Lewalter, Karl; Lemmen, Sebastian; Stijnis, Cornelis; Van der Meer, Jan; Soriano, Alex; Ruiz, Laura Morata; Arastéh, Keikawus; Stocker, Hartmut; Kluytmans, Jan; Veenemans, Jacobien; Brodt, Hans Reinhard; Stephan, Christoph; Wolf, Timo; Kessel, Johanna; Joost, Insa; Sinha, Bhanu; van Assen, Sander; Wilting, Kasper; Tobias Welte, Welte; Christiane Mölgen, Mölgen; Julia Freise, Freise; Brunkhorst, Frank; Pletz, Mathias; Hagel, Stefan; Becker, Christian; Frieling, Thomas; Kösters, Katrin; Reuter, Stefan; Hsiao, Mikai; Rupp, Jan; Dalhoff, Klaus; Turner, David; Snape, Susan; Crusz, Shanika; Venkatesan, Pradhib; Salzberger, Bernd; Hanses, Frank; Rodriguez-Baño, Jesùs; Méndez, Adoración Valiente; López-Cortés, Luis Eduardo; Cisneros, José Miguel; Navarro-Amuedo, Maria Dolores; Bonten, Marc; Oosterheert, Jan Jelrik; Ekkelenkamp, Miquel

    2015-01-01

    Background: Current guidelines recommend that patients with Staphylococcus aureus bloodstream infection (SAB) are treated with long courses of intravenous antimicrobial therapy. This serves to avoid SAB-related complications such as relapses, local extension and distant metastatic foci. However, in

  18. The evolution of vancomycin intermediate Staphylococcus aureus (VISA) and heterogenous-VISA.

    Science.gov (United States)

    Howden, Benjamin P; Peleg, Anton Y; Stinear, Timothy P

    2014-01-01

    Resistance to new antimicrobials is generally recognized in Staphylococcus aureus soon after they are released for clinical use. In the case of vancomycin, which was first released in the 1950s, resistance was not reported until the mid 1990s, with the description of vancomycin-intermediate S. aureus (VISA), and heterogenous-VISA (hVISA). Unraveling the complex genetic and cell wall structural changes conferring low-level vancomycin resistance in S. aureus has proved challenging. However the recent advances in high throughput whole-genome sequencing has played a key role in determining the breadth of bacterial chromosomal changes linked with resistance. Diverse mutations in a small number of staphylococcal regulatory genes, in particular walKR, graRS, vraSR and rpoB, have been associated with hVISA and VISA. Only a small number of these mutations have been experimentally proven to confer the resistance phenotype and some of these only partially contribute to resistance. It also appears that the evolution of VISA from VSSA is a step-wise process. Transcriptomics studies, and analysis of host pathogen interactions, indicate that the evolution of vancomycin-susceptible S. aureus to VISA is associated not only with antibiotic resistance, but with other changes likely to promote persistent infection. These include predicted alterations in central metabolism, altered expression of virulence associated factors, attenuated virulence in vivo, and alterations in susceptibility to host innate immune responses, together with reduced susceptibility to other antibiotics. In fact, current data suggests that hVISA and VISA represent a bacterial evolutionary state favoring persistence in the face of not only antibiotics, but also the host environment. The additional knowledge of staphylococcal biology that has been uncovered during the study of hVISA and VISA is significant. The present review will detail the current understanding of the evolutionary process in the generation of h

  19. Environmental Staphylococcus aureus contamination in a Tunisian hospital.

    Science.gov (United States)

    Gharsa, Haythem; Dziri, Raoudha; Klibi, Naouel; Chairat, Sarra; Lozano, Carmen; Torres, Carmen; Bellaaj, Ridha; Slama, Karim Ben

    2016-12-01

    One hundred hospital environment samples were obtained in 2012 in a Tunisian hospital and tested for Staphylococcus aureus recovery. Antimicrobial resistance profile and virulence gene content were determined. Multilocus-sequence-typing (MLST), spa-typing, agr-typing and SmaI-pulsed-field gel electrophoresis (PFGE) were performed. Two methicillin-resistant S. aureus (MRSA) isolates typed as: ST247-t052-SCCmecI-agrI were recovered from the intensive care unit (ICU). Ten samples contained methicillin-susceptible S. aureus (MSSA) and these samples were collected in different services, highlighting the presence of the tst gene encoding the toxic shock syndrome toxin as well as the lukED, hla, hlb, hld and hlgv virulence genes in some of the isolates. In conclusion, we have shown that the hospital environment could be a reservoir contributing to dissemination of virulent S. aureus and MRSA.

  20. Combating antimicrobial resistance: antimicrobial stewardship program in Taiwan.

    Science.gov (United States)

    Tseng, Shu-Hui; Lee, Chun-Ming; Lin, Tzou-Yien; Chang, Shan-Chwen; Chuang, Yin-Ching; Yen, Muh-Yong; Hwang, Kao-Pin; Leu, Hsieh-Shong; Yen, Che-Chieh; Chang, Feng-Yee

    2012-04-01

    Multi-drug-resistant organisms are increasingly recognized as a global public health issue. Healthcare-associated infection and antimicrobial resistance are also current challenges to the treatment of infectious diseases in Taiwan. Government health policies and the health care systems play a crucial role in determining the efficacy of interventions to contain antimicrobial resistance. National commitment to understand and address the problem is prerequisite. We analyzed and reviewed the antibiotic resistance related policies in Taiwan, USA, WHO and draft antimicrobial stewardship program to control effectively antibiotic resistance and spreading in Taiwan. Antimicrobial stewardship program in Taiwan includes establishment of national inter-sectoral antimicrobial stewardship task force, implementing antimicrobial-resistance management strategies, surveillance of HAI and antimicrobial resistance, conducting hospital infection control, enforcement of appropriate regulations and audit of antimicrobial use through hospital accreditation, inspection and national health insurance payment system. No action today, no cure tomorrow. Taiwan CDC would take a multifaceted, evidence-based approach and make every effort to combat antimicrobial resistance with stakeholders to limit the spread of multi-drug resistant strains and to reduce the generation of antibiotic resistant bacteria in Taiwan.

  1. Antimicrobial Activity.

    Science.gov (United States)

    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.

  2. The lysine-peptoid hybrid LP5 maintain activity under physiological conditions and affects virulence gene expression in Staphylococcus aureus

    DEFF Research Database (Denmark)

    Gottschalk, Sanne; Ingmer, Hanne; Thomsen, Line E.

    2016-01-01

    , we found that LP5 was protease resistant. However, the dltA and vraF genes, involved in reducing the net anionic charge of the bacterial cell envelope and sensing of antimicrobial peptides, respectively, played a role in the tolerance of S. aureus against LP5. In addition, the exposure of S. aureus...

  3. Eugenol Provokes ROS-Mediated Membrane Damage-Associated Antibacterial Activity Against Clinically Isolated Multidrug-Resistant Staphylococcus aureus Strains

    OpenAIRE

    2016-01-01

    Due to the indiscriminate use of antibiotics, resistance to antibiotics has increased remarkably in Staphylococcus aureus. Vancomycin is the final drug to treat the S. aureus infection, but nowadays, resistance to this antibiotic is also increasing. So, the investigation of antibiotic resistance pattern is important. As there is already resistance to vancomycin, there is an urgent need to develop a new kind of antimicrobial to treat S. aureus infection. Eugenol may be the new drug of choice. ...

  4. Effect of habituation to tea tree (Melaleuca alternifolia) oil on the subsequent susceptibility of Staphylococcus spp. to antimicrobials, triclosan, tea tree oil, terpinen-4-ol and carvacrol

    NARCIS (Netherlands)

    Thomsen, Natalie A.; Hammer, Katherine A.; Riley, Thomas V.; Van Belkum, Alex; Carson, Christine F.

    2013-01-01

    The aim of this study was to seek additional data on the antimicrobial susceptibility of Staphylococcus spp. after habituation to low levels of the topical antimicrobial agent tea tree (Melaleuca alternifolia) oil. Meticillin-susceptible Staphylococcus aureus (MSSA), meticillin-resistant S. aureus (

  5. Antimicrobial Activity of Metabolites of Various Strains of Lactobacillus acidophilus

    Directory of Open Access Journals (Sweden)

    Hassan Pyar Ali Hassan

    2011-01-01

    Full Text Available The antimicrobial activity of metabolites of eight strains of Lactobacillus acidophilus (FTDC 2804, FTDC 0785, FTDC 8592, FTDC 1295, FTDC 4793, FTDC 4462, FTDC 0582 and FTDC 2916 against  Staphylococcus aureus (gram positive and Escherichia coli (gram negative, was examined and compared using agar well diffusion method.  Lactobacillus acidophilus was cultivated in two different types of dairy growth medium namely, full cream milk and skim milk. The results showed that the metabolites of all the eight strains had significant antimicrobial effect based on zone of inhibition results when compared to control. There was a statistically significant difference in the zone of inhibition data for Staphylococcus aureus and Escherichia coli among the metabolites of the eight strains cultivated in the two different growth medium. Certain L. acidophilus strains were more effective against  Staphylococcus aureus, while other strains were more effective against  Escherichia coli. On the other hand, the growth medium had no significant influence on the antimicrobial effect of metabolites of seven strains except  L. acidophilus FTDC 4462 against Escherichia coli. As for  Staphylococcus aureus, the growth medium only affected the antimicrobial effect of metabolite of strain  L. acidophilus FTDC 1295, but did not affect the antimicrobial effect of metabolites of the other seven strains. It can be concluded that L. acidophilus cultivated in dairy products produced metabolites with antimicrobial property, which could provide beneficial medicinal values to human.

  6. Biological and immunotoxicity evaluation of antimicrobial peptide-loaded coatings using a layer-by-layer process on titanium

    Science.gov (United States)

    Shi, Jue; Liu, Yu; Wang, Ying; Zhang, Jing; Zhao, Shifang; Yang, Guoli

    2015-11-01

    The prevention and control of peri-implantitis is a challenge in dental implant surgery. Dental implants with sustained antimicrobial coating are an ideal way of preventing peri-implantitis. This study reports development of a non- immunotoxicity multilayered coating on a titanium surface that had sustained antimicrobial activity and limited early biofilm formation. In this study, the broad spectrum AMP, Tet213, was linked to collagen IV through sulfo-SMPB and has been renamed as AMPCol. The multilayer AMPCol coatings were assembled on smooth titanium surfaces using a LBL technique. Using XPS, AFM, contact angle analysis, and QCM, layer-by-layer accumulation of coating thickness was measured and increased surface wetting compared to controls was confirmed. Non-cytotoxicity to HaCaT and low erythrocyte hemolysis by the AMPCol coatings was observed. In vivo immunotoxicity assays showed IP administration of AMPCol did not effect serum immunoglobulin levels. This coating with controlled release of AMP decreased the growth of both a Gram-positive aerobe (Staphylococcus aureus) and a Gram-negative anaerobe (Porphyromonas gingivalis) up to one month. Early S. aureus biofilm formation was inhibited by the coating. The excellent long-term sustained antimicrobial activity of this multilayer coating is a potential method for preventing peri-implantitis through coated on the neck of implants before surgery.

  7. Tea Tree Oil-Induced Transcriptional Alterations in Staphylococcus aureus

    OpenAIRE

    Cuaron, Jesus A.; Dulal, Santosh; Song, Yang; Singh, Atul K; Montelongo, Cesar E.; Yu, Wanqin; Nagarajan, Vijayaraj; Jayaswal, Radheshyam K.; Wilkinson, Brian J; Gustafson, John E.

    2012-01-01

    Tea tree oil (TTO) is a steam distillate of Melaleuca alternifolia that demonstrates broad-spectrum antibacterial activity. This study was designed to document how TTO challenge influences the Staphylococcus aureus transcriptome. Overall, bioinformatic analyses (S. aureus microarray meta-database) revealed that both ethanol and TTO induce related transcriptional alterations. TTO challenge led to the down-regulation of genes involved with energy-intensive transcription and translation, and alt...

  8. Prevalence and antibiotic susceptibility of Staphylococcus aureus from bovine mastitis

    Directory of Open Access Journals (Sweden)

    C. G. Unakal and B. B. Kaliwal

    2010-04-01

    Full Text Available The primary objective of this study was to determine the prevalence and antimicrobial susceptibility of mastitic Staphylococcus aureus in dairy cows. Milk samples for microbiological culture were collected from dairy herds. A total of 105 samples were screened and 68 confirmed Staphylococcus aureus were obtained. The a, ß and non haemolytic activity revealed 20.58%, 75% and 4.41% respectively in 68 isolated strains of Staphylococcus aureus. Resistance of Staphylococcus aureus against 10 antimicrobial agents was tested using the disc diffusion method. The highest 86.76% isolates were resistant to penicillin followed by ampicillin 70.50%, amoxicillin 63.23%, gentamycin 47.05%, amikacin 30.80%, erythromycin 27.94%, Ciprofloxacin 26.47%, methicillin 23.52%, cefotaxime 20.58% and the lowest resistant was shown in ceftriaxone 19.11%. The study revealed that the increase in prevalence and antibiotic resistance pattern of the Staphylococcus aureus isolated from bovine mastitis. [Vet. World 2010; 3(2.000: 65-67

  9. The changing epidemiology of bacteraemias in Europe : trends from the European Antimicrobial Resistance Surveillance System

    NARCIS (Netherlands)

    de Kraker, M. E. A.; Jarlier, V.; Monen, J. C. M.; Heuer, O. E.; van de Sande, N.; Grundmann, H.

    2013-01-01

    We investigated bacteraemia trends for five major bacterial pathogens, Staphylococcus aureus, Escherichia coli, Streptococcus pneumoniae, Enterococcus faecalis and Enterococcus faecium, and determined how expanding antimicrobial resistance influenced the total burden of bacteraemias in Europe. Aetio

  10. Fresh garlic extract inhibits Staphylococcus aureus biofilm formation under chemopreventive and chemotherapeutic conditions

    Directory of Open Access Journals (Sweden)

    Panan Ratthawongjirakul

    2016-08-01

    Full Text Available Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA are the leading aetiological pathogens of nosocomial infections worldwide. These bacteria form biofilms on both biotic and abiotic surfaces causing biofilm-associated infections. Within the biofilm, these bacteria might develop persistent and antimicrobial resistant characteristics resulting in chronic infections and treatment failures. Garlic exhibits broad pharmaceutical properties and inhibitory activities against S. aureus. We investigated the effects of aqueous fresh garlic extract on biofilm formation in S. aureus ATCC25923 and MRSA strains under chemopreventive and chemotherapeutic conditions. The viable bacteria and biofilm levels were quantified through colony count and crystal violet staining, respectively. The use of fresh garlic extract under both conditions significantly inhibited biofilm formation in S. aureus strains ATCC25923 and MRSA. Garlic could be developed as either a prophylactic or therapeutic agent to manage S. aureus biofilm-associated infections.

  11. Antimicrobial susceptibility and presence of resistance genes in staphylococci from poultry

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Agersø, Yvonne; Ahrens, Peter

    2000-01-01

    to ciprofloxacin. Only six (7%) S. aureus isolates and one Staphylococcus saprophyticus were penicillin resistant. Resistance to sulphamethoxazole was observed among 16 (19%) of S. aureus isolates and two coagulase negative staphylococci (CNS). Twenty (24%) of the S. aureus isolates were resistant to erythromycin...... of conventional biochemical testing and 16S rDNA sequencing. The most common species were Staphylococcus aureus (83), Staphylococcus hyicus (11), Staphylococcus xylosus (9) and Staphylococcus cohnii (6). The isolates were susceptible to most antimicrobials tested. A high frequency of S. aureus (30%) was resistant...

  12. 光动力抗菌化学疗法治疗甲氧西林耐药金黄色葡萄球菌感染研究进展%Advances in the research of photodynamic antimicrobial chemotherapy for treating methicillin-resistant Staphylococcus aureus infection

    Institute of Scientific and Technical Information of China (English)

    张永军; 方勇; 姚敏

    2012-01-01

    This article reviews the advance in the research of both the mechanism of photodynamic antimicrobial chemotherapy (PACT) based on the principle of photodynamic therapy and the application of PACT in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infection.Nowadays an inexorable prevalence of resistant bacteria observed worldwide,among which MRSA strains typically have a high potential of provoking outbreaks with intractability,makes it a pressing issue to develop new germicidal strategies.FACT is an emerging photochemistry-based technology.In the presence of oxygen,PACT,with the aid of the activation of photosensitizers to generate reactive oxygen species by the wavelength-specific light,destroys the structure of bacteria selectively and efficiently,with much lower bacterial resistance level than that of antibiotics.We expect that further research would elucidate the mechanism and develop clinical applications of PACT,and it may become a novel approach to solve the problem of MRSA infection in the future.

  13. Analysis of the Antimicrobial-Resistant Gene and Virulence Gene Carried by Staphylococcus Aureus Collected from Bloodstream Infections in Tianjin:2006-2011%2006-2011年60株血感染金黄色葡萄球菌毒素及耐药基因分析

    Institute of Scientific and Technical Information of China (English)

    王立新; 胡神明; 胡志东; 田彬; 李静; 王凤霞; 杨华

    2013-01-01

    Objective To investigate resistance profile, antimicrobial-resistant genes and virulence genes carried by 60 staphylococcus aureus collected from bloodstream infections in General Hospital of Tianjin Medical University from 2006 to 2011.Methods The bacteria identification and the antimicrobial susceptibility test were conducted by VITEK-2 compact automatic system.Methicillin resistant staphylococcus aureus (MRSA) were screened by disk diffusion method with cefoxitin.The polymerase chain reaction (PCR)was used to detect genes of mecA, qacA, pvl, sea, seb, secI, sed, see and TSST-1.Results The resistance rates of 60 isolates to penicillin, erythromycin, clindamycin and gentamicin were 91.7%, 65.0%, 65.0% and 40.0%, respectively.All of the isolates were susceptible to vancomycin, linezolid, and tigecycline.Among the 60 isolates, the positive rates of mecA and qacA werel3 (21.7%) and 3(5.0%) respectively.The positive rates of pvl, sea, seb,sec and sed were 4 (6.7%),20(33.3%), 3 (5%),9 (15.0%) and 7 (11.7%).Both see and tst were negative in all strains.Conclusion The resistance rates of staphylococcus aureus collected from bloodstream infections were high to penicillin , erythromycin, clindamycin and gentamicin.The various toxin and the antimicrobial-resistant genes were positive in staphylococcus aureus.We should pay attention to the detection of the antimicrobial-resistant gene and virulence gene.%目的 了解2006-2011年临床分离的60株血感染金黄色葡萄球菌的耐药情况及毒素基因和耐药基因的流行情况.方法 VITEK 2-compact全自动细菌鉴定仪及配套鉴定卡、药敏卡对细菌进行鉴定及药敏试验;头孢西丁纸片扩散法筛选耐甲氧西林金黄色葡萄球菌(MRSA);应用聚合酶链反应(PCR)检测mecA、耐消毒剂基因(qacA)、杀白细胞素基因(pvl)、肠毒素基因(sea、seb、secl、sed、see)及中毒休克综合征毒素-1基因(tst).结果 60株金黄色葡萄球菌

  14. Curative effect of novel Rana catesbeiana antimicrobial peptide Temporin-La on Staphylococcus aureus infection in mouse model%新型牛蛙抗菌肽Temporin-La对金黄色葡萄球菌感染模型小鼠的治疗效果

    Institute of Scientific and Technical Information of China (English)

    赵瑞利; 韩文瑜; 韩俊友; 金天明; 冯新; 雷连成; 孙长江; 王选

    2013-01-01

    目的 探讨新型牛蛙抗菌肽Temporin-La对金黄色葡萄球菌感染模型小鼠的治疗效果.方法 采用二倍稀释法检测抗菌肽Temporine-La对临床主要致病菌的最小抑菌浓度(minimum inhibitory concentration,MIC);透射电镜观察Temporine-La对金黄色葡萄球菌的作用效果;复制金黄色葡萄球菌表皮感染小鼠模型,分别用4 U/ml青霉素和10μg/ml Temporin-La进行治疗,另设生理盐水对照组和空白对照组,感染后第4天,对各组小鼠进行白细胞计数、细菌计数、血管内皮生长因子(vascular endothelial growth factor,VEGF)表达水平检测及病理组织切片观察.结果 Temporin-La对革兰阳性菌的抑菌活性高于革兰阴性菌,其中对金黄色葡萄球菌的抑制作用最强;透射电镜观察显示,经100 μg/ml Temporin-La处理的金黄色葡萄球菌出现了质壁分离的现象,细胞壁缺失或发生裂解,金黄色葡萄球菌发生裂解而死亡;感染后第4天,青霉素组和Temporin-La组白细胞数及创面下肌肉组织细菌数均明显低于生理盐水对照组(P<0.05或P<0.01),Temporin-La组小鼠血清VEGF的表达水平明显高于青霉素组和空白对照组(P<0.05),青霉素组和Temporin-La组小鼠的创口修复情况明显优于生理盐水对照组.结论 Temporin-La具有抗小鼠金黄色葡萄球菌感染的效果,为其临床应用提供了实验依据,也为抗感染治疗提供了新的思路.%Objective To investigate the curative effect of a novel Rana catesbeiana antimicrobial peptide Temporin-La on Staphylococcus aureus infection in mouse model.Methods The minimum inhibitory concentration (MIC) of Temporine-La to major pathogens in clinic was determined by 2-fold dilution.The inhibitory effect of Temporine-La on S.aureus was observed by transmission electron microscopy.Mouse model of epidermal S.aureus infection was copied,and treated with 4 U/ml penicillin and 10 μg/ml Temporin-La respectively,using physiological

  15. Risk factors and antimicrobial susceptibilities of severe community-acquired Staphylococcus aureus infections in Ningbo%宁波地区社区获得性金黄色葡萄球菌重症感染危险因素及菌株药物敏感性分析

    Institute of Scientific and Technical Information of China (English)

    常燕子; 裘莉佩; 崔裕山; 孙珺; 高国生

    2015-01-01

    Objective To identify antimicrobial susceptibilities of community-acquired Staphylococcus aureus infections and the risk factors of severe infections.Methods Clinical data of 184 cases of community-acquired Staphylococcus aureus infections collected from 4 hospitals in Ningbo during May 2008 and May 2013 were reviewed.Microbial sensitivity test and virulence genes ( pvl and tst) detection were performed in clinical isolates, and SCCmec genotyping was performed in methicillin-resistant Staphylococcus aureus ( MRSA) strains.Binary logistic regression analysis was used to identify the risk factors for severe infections.Results Among 184 cases of community-acquired Staphylococcus aureus infections, 39 ( 21.20%) were severe cases. Staphylococcus aureus strains were highly resistant to penicillin, erythromycin and clindamycin, but more than 75% strains were sensitive to oxacillin, aminoglycosides, quinolones, rifampicin and vancomycin.Logistic regression analysis showed that advanced age (OR=1.024, 95%CI:1.005-1.043, P<0.05), malignant tumor (OR=15.288, 95%CI:1.609-145.229, P<0.05) , autoimmune diseases or long-term hormone therapy ( OR=12.102, 95%CI:2.082-70.338, P <0.01 ) were risk factors for severe community-acquired Staphylococcus aureus infections. Conclusions Strains isolated from the patients with community-acquired Staphylococcus aureus infections in Ningbo are usually sensitive to oxacillin, aminoglycosides, quinolones, rifampicin and vancomycin, which may be recommended for clinical use.Elder patients and those with malignant tumor, autoimmune diseases or long-term hormone therapy are more likely to develop severe Staphylococcus aureus infections.%目的:了解宁波地区社区获得性金黄色葡萄球菌重症感染发生的危险因素和菌株对常用抗菌药物的敏感性。方法连续收集2008年5月至2013年5月宁波地区4家医院184例社区获得性金黄色葡萄球菌感染病例的资料及分离的菌株。对患者一般特征(

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

    Directory of Open Access Journals (Sweden)

    Stephanie de Rapper

    2016-01-01

    Full Text Available 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.

  17. Antimicrobials, stress and mutagenesis.

    Directory of Open Access Journals (Sweden)

    Alexandro Rodríguez-Rojas

    2014-10-01

    Full Text Available Cationic antimicrobial peptides are ancient and ubiquitous immune effectors that multicellular organisms use to kill and police microbes whereas antibiotics are mostly employed by microorganisms. As antimicrobial peptides (AMPs mostly target the cell wall, a microbial 'Achilles heel', it has been proposed that bacterial resistance evolution is very unlikely and hence AMPs are ancient 'weapons' of multicellular organisms. Here we provide a new hypothesis to explain the widespread distribution of AMPs amongst multicellular organism. Studying five antimicrobial peptides from vertebrates and insects, we show, using a classic Luria-Delbrück fluctuation assay, that cationic antimicrobial peptides (AMPs do not increase bacterial mutation rates. Moreover, using rtPCR and disc diffusion assays we find that AMPs do not elicit SOS or rpoS bacterial stress pathways. This is in contrast to the main classes of antibiotics that elevate mutagenesis via eliciting the SOS and rpoS pathways. The notion of the 'Achilles heel' has been challenged by experimental selection for AMP-resistance, but our findings offer a new perspective on the evolutionary success of AMPs. Employing AMPs seems advantageous for multicellular organisms, as it does not fuel the adaptation of bacteria to their immune defenses. This has important consequences for our understanding of host-microbe interactions, the evolution of innate immune defenses, and also sheds new light on antimicrobial resistance evolution and the use of AMPs as drugs.

  18. Antimicrobial hyperbranched poly(ester amide)/polyaniline nanofiber modified montmorillonite nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Pramanik, Sujata [Advanced Polymer and Nanomaterial Laboratory, Department of Chemical Sciences, Tezpur University, Tezpur 784028 (India); Bharali, Pranjal; Konwar, B.K. [Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028 (India); Karak, Niranjan, E-mail: karakniranjan@yahoo.com [Advanced Polymer and Nanomaterial Laboratory, Department of Chemical Sciences, Tezpur University, Tezpur 784028 (India)

    2014-02-01

    There has been growing interest in the use of nanomaterials featuring potent of antimicrobial activity in the biomedical domain. It still remains a challenge for the researchers to develop an efficient nanocomposite possessing antimicrobial efficacy against broad spectrum microbes including bacteria, fungi as well as algal consortium, posing serious challenges for the human survival. In addressing the above problem, we report the fabrication of bio-based hyperbranched poly(ester amide) (HBPEA)/polyaniline nanofiber modified montmorillonite (MMT) nanocomposites by an ex-situ polymerization technique at varied weight percentages (1, 2.5, 5 wt.%) of the modified MMT (nanohybrid). The Fourier transform infrared spectroscopy confirmed the structural changes upon interaction of the nanohybrid with HBPEA. A probable mechanism is proposed for the formation of nanocomposites with partially exfoliated nanoplatelet structure, which was further confirmed from the high resolution transmission electron microscopic analyses. The prepared nanocomposites exhibited potent efficacy against gram positive bacteria like Bacillus subtilis and Staphylococcus aureus as compared to the gram negative ones like Pseudomonas aeruginosa and Escherichia coli. The nanocomposites showed significant antifungal activity against Aspergillus niger, Fusarium oxysporum and Coleotricum capcii and antialgal activity against algal consortium comprising of Chlorella, Hormidium and Cladophorella species. The formation of thermosetting nanocomposites resulted in the acceptable improvement of desired physico-chemical and mechanical properties including thermostability. Thus pronounced antimicrobial activity of the nanocomposites against a spectrum of bacterial and fungal strains as well as a consortium of algal species along with other desired performance vouched them as potent antimicrobial materials in the realm of health and biomedical industry. - Highlights: • A possible approach for fabrication of the

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

    Science.gov (United States)

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

    2012-01-01

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

  20. Synthesis and antimicrobial activity of amphiphilic carbohydrate derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Reis, Roberta C.N.; Oda, Simone C.; Almeida, Mauro V. de; Le Hyaric, Mireille [Universidade Federal de Juiz de Fora (UFJF), MG (Brazil). Dept. de Quimica]. E-mail: mireille.hyaric@ufjf.edu.br; Lourenco, Maria C.S.; Vicente, Felipe R.C. [Fundacao Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, RJ (Brazil ). Instituto de Pesquisa Clinica Evandro Chagas (IPEC); Barbosa, Nadia R.; Trevizani, Rafael; Santos, Priscila L.C. [Universidade Federal de Juiz de Fora (UFJF), MG (Brazil). Faculdade de Farmacia e Bioquimica

    2008-07-01

    N-monoalkylated diamines were synthesised and treated with D-ribonolactone or D-gluconolactone. The resulting aldonamides were evaluated for their antimicrobial activity against S. aureus, E. coli, M. tuberculosis and C. albicans. Two hydrazides were also prepared from ribonohydrazide and their biological activity was compared to their amide analogues. All the ribono-derivatives displayed moderated antitubercular activity, and some of them were also active against S. aureus. (author)

  1. Antimicrobial activity and phytochemical screening 4 of Arbutus unedo L

    OpenAIRE

    Dib, Mohamed El Amine; Allali, Hocine; Bendiabdellah, Amel; Meliani, Nawel; Tabti, Boufeldja

    2012-01-01

    In this study, antimicrobial activities of water and methanol extract, and three phenolic fractions of the roots of Arbutus unedo L. were investigated. Poor antibacterial activity against both Staphylococcus aureus and Pseudomonas aeruginosa bacteria was shown with water and methanol extract. However moderate antibacterial activity was shown by water extract and phenolic fractions against Escherichia coli and S. aureus, respectively. The phytochemical screening of roots of A. u...

  2. Antimicrobial activity of bioactive component from flower of linum capitatum kit

    OpenAIRE

    Ilić Slavica V.; Konstantinović Sandra S.; Todorović Zoran B.

    2004-01-01

    Different extracts containing bioactive components and etheric oil of the flowers of Linum capitation kit. (Linacea) of Serbian origin were tested for an Antimicrobial activity against four bacteria (Staphylococcus aureus Escherichia coli, Bacillus subtilus, Pseudomonas aeruginosa), one mold (Aspergillus niger) and one yeast (Candida albicans). The isolated Flavonoids were also tested against Staphylococcus aureus, Escherichia coli Bacillus anhtracis, Pseudomonas aeruginosa, Aspergillus niger...

  3. Synthesis of a novel multi N-halamines siloxane precursor and its antimicrobial activity on cotton

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Lin; Xu, Yan; Cai, Lu; Zang, Xiong [National Engineering Laboratory for Modern Silk, Suzhou 215123 (China); College of Textile and Clothing Engineering, Soochow University, No 199 Renai Road, Industry Park, Suzhou 215021 (China); Li, Zhanxiong, E-mail: lizhanxiong@suda.edu.cn [National Engineering Laboratory for Modern Silk, Suzhou 215123 (China); College of Textile and Clothing Engineering, Soochow University, No 199 Renai Road, Industry Park, Suzhou 215021 (China)

    2014-09-30

    A novel N-halamine siloxane antibacterial precursor N-(3-triethoxysilylpropyl)-N′- (N″′-heptylcarbamido-N″-ethyl)-butanediamide (TSHCEB) was synthesized and characterized in this study. The compound was then tethered to the surface of cotton fabrics through covalent ether linkages, followed by exposure to dilute sodium hypochlorite solutions to confer the cotton fabrics antibacterial property. The chemical structure of the monomer was confirmed by FTIR, {sup 1}H NMR and MS, and the surface of the treated cotton fabrics was characterized by FTIR, TGA, SEM, and XPS analysis. The antimicrobial cotton materials were then challenged with Gram-negative Escherichia coli O157:H7 (ATCC 43895) and Gram-positive Staphylococcus aureus (ATCC 6538). Results showed that it provided excellent antimicrobial properties against E. coli O157:H7 and S. aureus via direct contacting for 2–15 min. The controlled release of diverse chlorines was proved by inhibition zone. The chlorine bonded to the coating was stable under standard washing test and routine storage, stability toward UVA irradiation was also investigated, and the lost chlorine could be regenerated by rechlorination. The new N-halamine antibacterial precursor can provide superior antibacterial property within a short contact time.

  4. Antimicrobial activity and phytochemical analysis of selected Indian folk medicinal plants

    Directory of Open Access Journals (Sweden)

    Mohamed Sham Shihabudeen. H

    2010-11-01

    Full Text Available The success of chemotherapy lies in the continuous search for new drugs to counter the challenge posed by resistant strains. Methanol extracts of six plant species traditionally used in Indian folklore medicine for the treatment of various bacterial and fungal infections were investigated for in vitro antimicrobial activity against pathogens namely Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger by disc diffusion method. Methanol extracts of Eugenia jambolana and Cassia auriculata showed the highest toxicity against all the bacteria. The plant extracts showed antibacterial activity but not antifungal activity against any of the fungi used. Minimum inhibitory concentration (MIC assay were determined for these two extracts against bacteria. E. jambolana revealed the highest antimicrobial activity at a minimum oncentration (0.75 mg/ml against S. aureus. The phytochemical analysis carried out revealed the presence of coumarins, flavanoids, glycosides, phenols, tannins, saponins and steroids. Alkaloids were not detected from any of the plant extracts under study. The resultsprovide justification for the use of the plants in folk medicine to treat various infectious diseases.

  5. The first salamander defensin antimicrobial peptide.

    Directory of Open Access Journals (Sweden)

    Ping Meng

    Full Text Available 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.

  6. ANTIMICROBIAL ACTIVITY OF LACTIC ACID BACTERIAL ISOLATES

    Directory of Open Access Journals (Sweden)

    Utkarsha S. Shivsharan

    2013-08-01

    Full Text Available Micro-organisms have tendency to produce antimicrobial substances which show biological activity against other kind of micro-organisms. This phenomenon of bacterial antagonism is observed in lactic acid bacteria with competitive advantages. The lactic acid bacteria are commonly present in many fermented products, fruits and milk products. The variety of antimicrobial substances produced by lactic acid bacteria showing good inhibition capacity include production of lactic acid, acetic acid, hydrogen peroxide, carbon dioxide, diacetyl and bacteriocin. Bacteriocins produced by lactic acid bacteria are the subject of intense research because of their antimicrobial activity against food born bacteria such as Listeria monocytogenes, staphylococcus aureus, Bacillus cereus, Clostridium botulinum and several others .Bacteriocins may be bacteriostatic or bactericidal with narrow or broad range of activity. The main of the study was to study the antimicrobial activity of such lactic acid bacterial isolates.

  7. Antibiotic Resistance in Staphylococcus aureus and Coagulase Negative Staphylococci Isolated from Goats with Subclinical Mastitis

    Directory of Open Access Journals (Sweden)

    Salvatore Virdis

    2010-01-01

    Full Text Available Antimicrobial resistance patterns and gene coding for methicillin resistance (mecA were determined in 25 S. aureus and 75 Coagulase Negative Staphylococci (CNS strains isolates from half-udder milk samples collected from goats with subclinical mastitis. Fourteen (56.0% S. aureus and thirty-one (41.3% CNS isolates were resistant to one or more antimicrobial agents. S. aureus showed the highest resistance rate against kanamycin (28.0%, oxytetracycline (16.0%, and ampicillin (12.0%. The CNS tested were more frequently resistant to ampicillin (36.0% and kanamycin (6.7%. Multiple antimicrobial resistance was observed in eight isolates, and one Staphylococcus epidermidis was found to be resistant to six antibiotics. The mecA gene was not found in any of the tested isolates. Single resistance against β-lactamics or aminoglicosides is the most common trait observed while multiresistance is less frequent.

  8. Antimicrobial resistance in Dschang, Cameroon

    Directory of Open Access Journals (Sweden)

    Fusi-Ngwa Catherine Kesah

    2013-01-01

    Full Text Available Background: Health-care-associated and community infections remain problematic in most of Africa where the increasing incidences of diseases, wars, poverty, malnutrition, and general environmental deterioration have led to the gradual collapse of the health-care system. Detection of antimicrobial resistance (AMR remains imperative for the surveillance purposes and optimal management of infectious diseases. This study reports the status of AMR in pathogens in Dschang. Materials and Methods: From May 2009 to March 2010, the clinical specimens collected at two hospitals were processed accorded to the standard procedures. Antibiotic testing was performed by E test, and antimycotics by disc-agar diffusion, as recommended by the Clinical and Laboratory Standards Institute on pathogens comprising Staphylococcus aureus (100 strains, Enterococcus faecalis (35, Klebsiella pneumoniae (75, Escherichia coli (50, Proteus mirabilis (30, Pseudomonas aruginosa (50, Acinetobacter species (20, and Candida albicans (150 against common antimicrobials. Results: There was no vancomycin resistance in the cocci, the minimum inhibitory concentration for 90% of these strains MIC 90 was 3 μg/ml, methicillin-resistant S. aureus (MRSA was 43%, benzyl penicillin 89% resistance in S. aureus as opposed to 5.7% in E. faecalis. Low resistance (<10% was recorded to cefoxitin, cefotaxime, and nalidixic acid (MIC 90 3-8 μg/ml against the coliforms, and to ticarcillin, aztreonam, imipenem, gentamicin, and ciprofloxacin among the non-enterobacteria; tetracycline, amoxicillin, piperacillin, and chloramphenicol were generally ineffective. Resistance rates to fluconazole, clotrimazole, econazole, and miconazole were <55% against C. albicans. The pathogens tested exhibited multidrug-resistance. Conclusion: The present findings were intended to support antimicrobial stewardship endeavors and empiric therapy. The past, present, and the future investigations in drug efficacy will continue

  9. Antimicrobial Resistance

    Science.gov (United States)

    ... emergence and spread of antibacterial resistance, including optimal use of antibiotics in both humans and animals. A global action plan on antimicrobial resistance was adopted by Member States at the ...

  10. Evaluation of antimicrobial properties of cork.

    Science.gov (United States)

    Gonçalves, Filipa; Correia, Patrícia; Silva, Susana P; Almeida-Aguiar, Cristina

    2016-02-01

    Cork presents a range of diverse and versatile properties making this material suitable for several and extremely diverse industrial applications. Despite the wide uses of cork, its antimicrobial properties and potential applications have deserved little attention from industry and the scientific community. Thus, the main purpose of this work was the evaluation of the antibacterial properties of cork, by comparison with commercially available antimicrobial materials (Ethylene-Vinyl Acetate copolymer and a currently used antimicrobial commercial additive (ACA)), following the previous development and optimization of a method for such antimicrobial assay. The AATCC 100-2004 standard method, a quantitative procedure developed for the assessment of antimicrobial properties in textile materials, was used as reference and optimized to assess cork antibacterial activity. Cork displayed high antibacterial activity against Staphylococcus aureus, with a bacterial reduction of almost 100% (96.93%) after 90 minutes of incubation, similar to the one obtained with ACA. A more reduced but time-constant antibacterial action was observed against Escherichia coli (36% reduction of the initial number of bacterial colonies). To complement this study, antibacterial activity was further evaluated for a water extract of cork and an MIC of 6 mg mL(-1) was obtained against the reference strain S. aureus.

  11. Effect of ethanolic extract of Ecballium elaterium against Staphylococcus aureus and Candida albicans

    Institute of Scientific and Technical Information of China (English)

    Ghaleb Adwan; Yousef Salameh; Kamel Adwan

    2011-01-01

    To evaluate the antimicrobial activity of ethanolic extract of Ecballium elaterium (E.elaterium) fruits alone against Staphylococcus aureus (S. aureus) strains and Candida albicans (C. albicans) strains, or in combination with penicillin against Staphylococcus areus strains. Methods: Evaluation of the antimicrobial activity or synergy interaction was carried out using microdilution method. Results: The results showed that ethanolic extract of E. elaterium fruits has antimicrobial activity against methicillin resistant S. aureus (MRSA), methicillin sensitive S.aureus (MSSA) and C. albicans. This extract showed a significant decrease in minimum inhibitory concentrations (MIC) of penicillin against both MRSA and MSSA strains. Fractional inhibitory concentration index (FIC) between penicillin and ethanolic extract of E. elaterium fruits against these test strains was less than 0.5. Conclusions: This study suggests that ethanolic extract of E. elaterium fruits has antimicrobial activity against S. aureus and C. albicans and there is a possibility of concurrent use of penicillin and E. elaterium extract in combination in the treatment of infections caused by MRSA and MSSA strains. A wider study is needed to identify the effective components, the mode of action and the possible toxic effect in vivo of these ingredients.

  12. Antimicrobial coatings — obtaining and characterization

    Indian Academy of Sciences (India)

    Cornelia Guran; Alexandra Pica; Denisa Ficai; Anton Ficai; Cezar Comanescu

    2013-04-01

    In this paper, we present inorganic–organic hybrid coatings with polymer matrix (water soluble) that contain silver nanoparticles (AgNPs). The structure and morphology of coating materials were determined by infrared spectroscopy (FT–IR) and scanning electron microscopy (SEM). Therefore, the antimicrobial activities and mechanisms of coatings for several pathogenic bacteria (Bacilius cereus and Staphylococcus aureus) were investigated. It was demonstrated that the obtained material with silver nanoparticles keep their antimicrobial effect even if they are subjected to several cycles of washing with water and detergent.

  13. In vitro assessment of the antimicrobial activity of wound dressings: influence of the test method selected and impact of the pH.

    Science.gov (United States)

    Wiegand, Cornelia; Abel, Martin; Ruth, Peter; Elsner, Peter; Hipler, Uta-Christina

    2015-01-01

    Antibacterial activity of dressings containing antimicrobials is mostly evaluated using in vitro tests. However, the various methods available differ significantly in their properties and results obtained are influenced by the method selected, micro-organisms used, and extraction method, the degree of solubility or the diffusability of the test-compounds. Here, results on antimicrobial activity of silver-containing dressings obtained by agar diffusion test (ADT), challenge tests (JIS L 1902, AATCC 100), and extraction-based methods (microplate laser nephelometry (MLN), luminescent quantification of bacterial ATP (LQbATP)) using Staphylococcus aureus and Pseudomonas aeruginosa were evaluated. Furthermore, the effect of the pH on antibacterial efficacy of these dressings was investigated. All silver-containing dressings exerted antimicrobial activity in all in vitro tests and results correlated considerably well. Differences were observed testing the agent-free basic materials. They did not exhibit any antimicrobial effects in the ADT, MLN or LQbATP, since these methods depend on diffusion/extraction of an active agent. However, they showed a strong antimicrobial effect in the challenge tests as they possess a high absorptive capacity, and are able to bind and sequester micro-organisms present. Therefore, it seems recommendable to choose several tests to distinguish whether a material conveys an active effect or a passive mechanism. In addition, it could be shown that release of silver and its antimicrobial efficacy is partially pH-dependent, and that dressings themselves affect the pH. It can further be speculated that dressings' effects on pH and release of silver ions act synergistically for antimicrobial efficacy.

  14. Nanoscale Plasma Coating Inhibits Formation of Staphylococcus aureus Biofilm

    OpenAIRE

    2015-01-01

    Staphylococcus aureus commonly infects medical implants or devices, with devastating consequences for the patient. The infection begins with bacterial attachment to the device, followed by bacterial multiplication over the surface of the device, generating an adherent sheet of bacteria known as a biofilm. Biofilms resist antimicrobial therapy and promote persistent infection, making management difficult to futile. Infections might be prevented by engineering the surface of the device to disco...

  15. Staphylococcus aureus entrance into the dairy chain: Tracking S. aureus from dairy cow to cheese

    Directory of Open Access Journals (Sweden)

    Judith Kümmel

    2016-10-01

    Full Text Available Staphylococcus aureus is one of the most important contagious mastitis pathogens in dairy cattle. Due to its zoonotic potential, control of S. aureus is not only of great economic importance in the dairy industry but also a significant public health concern. The aim of this study was to decipher the potential of bovine udder associated S. aureus as reservoir for S. aureus contamination in dairy production and processing. From 18 farms, delivering their milk to an alpine dairy plant for the production of smeared semi-hard and hard cheese. 1176 quarter milk (QM samples of all cows in lactation (n = 294 and representative samples form bulk tank milk (BTM of all farms were surveyed for coagulase positive (CPS and coagulase negative Staphylococci (CNS. Furthermore, samples from different steps of the cheese manufacturing process were tested for CPS and CNS. As revealed by chemometric-assisted FTIR spectroscopy and molecular subtyping (spa typing and multi locus sequence typing, dairy cattle represent indeed an important, yet underreported, entrance point of S. aureus into the dairy chain. Our data clearly show that certain S. aureus subtypes are present in primary production as well as in the cheese processing at the dairy plant. However, although a considerable diversity of S. aureus subtypes was observed in QM and BTM at the farms, only certain S. aureus subtypes were able to enter and persist in the cheese manufacturing at the dairy plant and could be isolated from cheese until day fourteen of ripening. Farm strains belonging to the FTIR cluster B1 and B3, which show genetic characteristics (t2953, ST8, enterotoxin profile: sea/sed/sej of the recently described S. aureus genotype B, most successfully contaminated the cheese production at the dairy plant. Thus our study fosters the hypothesis that genotype B S. aureus represent a specific challenge in control of S. aureus in the dairy chain that requires effective clearance strategies and hygienic

  16. Staphylococcus aureus Entrance into the Dairy Chain: Tracking S. aureus from Dairy Cow to Cheese

    Science.gov (United States)

    Kümmel, Judith; Stessl, Beatrix; Gonano, Monika; Walcher, Georg; Bereuter, Othmar; Fricker, Martina; Grunert, Tom; Wagner, Martin; Ehling-Schulz, Monika

    2016-01-01

    Staphylococcus aureus is one of the most important contagious mastitis pathogens in dairy cattle. Due to its zoonotic potential, control of S. aureus is not only of great economic importance in the dairy industry but also a significant public health concern. The aim of this study was to decipher the potential of bovine udder associated S. aureus as reservoir for S. aureus contamination in dairy production and processing. From 18 farms, delivering their milk to an alpine dairy plant for the production of smeared semi-hard and hard cheese. one thousand hundred seventy six one thousand hundred seventy six quarter milk (QM) samples of all cows in lactation (n = 294) and representative samples form bulk tank milk (BTM) of all farms were surveyed for coagulase positive (CPS) and coagulase negative Staphylococci (CNS). Furthermore, samples from different steps of the cheese manufacturing process were tested for CPS and CNS. As revealed by chemometric-assisted FTIR spectroscopy and molecular subtyping (spa typing and multi locus sequence typing), dairy cattle represent indeed an important, yet underreported, entrance point of S. aureus into the dairy chain. Our data clearly show that certain S. aureus subtypes are present in primary production as well as in the cheese processing at the dairy plant. However, although a considerable diversity of S. aureus subtypes was observed in QM and BTM at the farms, only certain S. aureus subtypes were able to enter and persist in the cheese manufacturing at the dairy plant and could be isolated from cheese until day 14 of ripening. Farm strains belonging to the FTIR cluster B1 and B3, which show genetic characteristics (t2953, ST8, enterotoxin profile: sea/sed/sej) of the recently described S. aureus genotype B, most successfully contaminated the cheese production at the dairy plant. Thus, our study fosters the hypothesis that genotype B S. aureus represent a specific challenge in control of S. aureus in the dairy chain that requires

  17. Staphylococcus aureus biofilms: recent developments in biofilm dispersal.

    Science.gov (United States)

    Lister, Jessica L; Horswill, Alexander R

    2014-01-01

    Staphylococcus aureus is a major cause of nosocomial and community-acquired infections and represents a significant burden on the healthcare system. S. aureus attachment to medical implants and host tissue, and the establishment of a mature biofilm, play an important role in the persistence of chronic infections. The formation of a biofilm, and encasement of cells in a polymer-based matrix, decreases the susceptibility to antimicrobials and immune defenses, making these infections difficult to eradicate. During infection, dispersal of cells from the biofilm can result in spread to secondary sites and worsening of the infection. In this review, we discuss the current understanding of the pathways behind biofilm dispersal in S. aureus, with a focus on enzymatic and newly described broad-spectrum dispersal mechanisms. Additionally, we explore potential applications of dispersal in the treatment of biofilm-mediated infections.

  18. Exaggerated Acute Lung Injury and Impaired Antibacterial Defenses During Staphylococcus aureus Infection in Rats with the Metabolic Syndrome.

    Directory of Open Access Journals (Sweden)

    Xiaomei Feng

    Full Text Available Rats with Metabolic Syndrome (MetaS have a dysregulated immune response to the aseptic trauma of surgery. We hypothesized that rats with MetaS would have dysregulated inflammation, increased lung injury, and less effective antibacterial defenses during Staphylococcus (S. aureus sepsis as compared to rats without MetaS. Low capacity runner (LCR; a model of MetaS and high capacity runner (HCR rats were challenged intravenously with S. aureus bacteria. After 48 h, inflammatory mediators and bacteria were quantified in the blood, bronchoalveolar lavage fluid (BALF, and lung homogenates. Lungs were analyzed histologically. BALF protein and lung wet-dry ratios were quantified to assess for vascular leak. Endpoints were compared in infected LCR vs HCR rats. LCR rats had higher blood and lung S. aureus counts, as well as higher levels of IL-6 in plasma, lungs and BALF, MIP-2 in plasma and lung, and IL-17A in lungs. Conversely, LCR rats had lower levels of IL-10 in plasma and lungs. Although lactate levels, and liver and renal function tests were similar between groups, LCR rats had higher BALF protein and lung wet-dry ratios, and more pronounced acute lung injury histologically. During S. aureus bacteremia, as compared with HCR rats, LCR (MetaS rats have heightened pro-inflammatory responses, accompanied by increased acute lung injury and vascular leak. Notably, despite an augmented pro-inflammatory phenotype, LCR rats have higher bacterial levels in their blood and lungs. The MetaS state may exacerbate lung injury and vascular leak by attenuating the inflammation-resolving response, and by weakening antimicrobial defenses.

  19. Exaggerated Acute Lung Injury and Impaired Antibacterial Defenses During Staphylococcus aureus Infection in Rats with the Metabolic Syndrome.

    Science.gov (United States)

    Feng, Xiaomei; Maze, Mervyn; Koch, Lauren G; Britton, Steven L; Hellman, Judith

    2015-01-01

    Rats with Metabolic Syndrome (MetaS) have a dysregulated immune response to the aseptic trauma of surgery. We hypothesized that rats with MetaS would have dysregulated inflammation, increased lung injury, and less effective antibacterial defenses during Staphylococcus (S.) aureus sepsis as compared to rats without MetaS. Low capacity runner (LCR; a model of MetaS) and high capacity runner (HCR) rats were challenged intravenously with S. aureus bacteria. After 48 h, inflammatory mediators and bacteria were quantified in the blood, bronchoalveolar lavage fluid (BALF), and lung homogenates. Lungs were analyzed histologically. BALF protein and lung wet-dry ratios were quantified to assess for vascular leak. Endpoints were compared in infected LCR vs HCR rats. LCR rats had higher blood and lung S. aureus counts, as well as higher levels of IL-6 in plasma, lungs and BALF, MIP-2 in plasma and lung, and IL-17A in lungs. Conversely, LCR rats had lower levels of IL-10 in plasma and lungs. Although lactate levels, and liver and renal function tests were similar between groups, LCR rats had higher BALF protein and lung wet-dry ratios, and more pronounced acute lung injury histologically. During S. aureus bacteremia, as compared with HCR rats, LCR (MetaS) rats have heightened pro-inflammatory responses, accompanied by increased acute lung injury and vascular leak. Notably, despite an augmented pro-inflammatory phenotype, LCR rats have higher bacterial levels in their blood and lungs. The MetaS state may exacerbate lung injury and vascular leak by attenuating the inflammation-resolving response, and by weakening antimicrobial defenses.

  20. The in-vitro antimicrobial activity of some medicinal plants against beta-lactam-resistant bacteria

    OpenAIRE

    Gangoue Pieboji, Joseph; Eze, N.; Ngongang Djintchui, A.; Ngameni, B; Tsabang, N.; Pegnyemb, D. E.; Biyiti, L.; Ngassam, P.; Koulla-Shiro, S.; Galleni, Moreno

    2009-01-01

    BACKGROUND: In effort to identify novel bacterial agents, this study was initiated to evaluate the antimicrobial properties of 17 crude extracts from 12 medicinal plants against beta-lactam-resistant bacteria. METHODOLOGY: The antimicrobial activities of plant extracts were evaluated against clinically proved beta-lactam-resistant bacteria (Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae, Serratia marcescens, Acinetobacter baumannii, Staphylococcus aureus and Enterococcus sp.)...

  1. Therapeutic antimicrobial peptides may compromise natural immunity.

    Science.gov (United States)

    Habets, Michelle G J L; Brockhurst, Michael A

    2012-06-23

    Antimicrobial peptides (AMPs) have been proposed as a promising new class of antimicrobials despite warnings that therapeutic use could drive the evolution of pathogens resistant to our own immunity peptides. Using experimental evolution, we demonstrate that Staphylococcus aureus rapidly evolved resistance to pexiganan, a drug-candidate for diabetic leg ulcer infections. Evolved resistance was costly in terms of impaired growth rate, but costs-of-resistance were completely ameliorated by compensatory adaptation. Crucially, we show that, in some populations, experimentally evolved resistance to pexiganan provided S. aureus with cross-resistance to human-neutrophil-defensin-1, a key component of the innate immune response to infection. This unintended consequence of therapeutic use could drastically undermine our innate immune system's ability to control and clear microbial infections. Our results therefore highlight grave potential risks of AMP therapies, with implications for their development.

  2. Impact of interspecific interactions on antimicrobial activity among soil bacteria.

    Science.gov (United States)

    Tyc, Olaf; van den Berg, Marlies; Gerards, Saskia; van Veen, Johannes A; Raaijmakers, Jos M; de Boer, Wietse; Garbeva, Paolina

    2014-01-01

    Certain bacterial species produce antimicrobial compounds only in the presence of a competing species. However, little is known on the frequency of interaction-mediated induction of antibiotic compound production in natural communities of soil bacteria. Here we developed a high-throughput method to screen for the production of antimicrobial activity by monocultures and pair-wise combinations of 146 phylogenetically different bacteria isolated from similar soil habitats. Growth responses of two human pathogenic model organisms, Escherichia coli WA321 and Staphylococcus aureus 533R4, were used to monitor antimicrobial activity. From all isolates, 33% showed antimicrobial activity only in monoculture and 42% showed activity only when tested in interactions. More bacterial isolates were active against S. aureus than against E. coli. The frequency of interaction-mediated induction of antimicrobial activity was 6% (154 interactions out of 2798) indicating that only a limited set of species combinations showed such activity. The screening revealed also interaction-mediated suppression of antimicrobial activity for 22% of all combinations tested. Whereas all patterns of antimicrobial activity (non-induced production, induced production and suppression) were seen for various bacterial classes, interaction-mediated induction of antimicrobial activity was more frequent for combinations of Flavobacteria and alpha- Proteobacteria. The results of our study give a first indication on the frequency of interference competitive interactions in natural soil bacterial communities which may forms a basis for selection of bacterial groups that are promising for the discovery of novel, cryptic antibiotics.

  3. Biosynthesis of Silver Nanoparticles Using the Phototrophic Bacteria Rhodopseudomonas palustris and Its Antimicrobial Activity Against Escherichia coli and Staphylococcus aureus%沼泽红假单胞菌生物合成银纳米粒子及其抗菌作用

    Institute of Scientific and Technical Information of China (English)

    柴春镜; 白红娟

    2010-01-01

    近年来,利用沼泽红假单胞菌合成银纳米粒子作为一种可靠和环境友好的方法出现.主要利用沼泽红假单胞菌的细胞滤液来还原银离子.制备的纳米粒子用紫外可见光谱(UV-vis)、X射线衍射光谱(XRD)和透射电镜(TEM)进行表征.含有银粒子溶液的UV-vis光谱显示在420 nm-460 nm处出现银纳米粒子的吸收峰.TEM图像表明所形成的银纳米粒子的粒径范围为5 nm-20 nm.纳米粒子的XRD图谱证明产物为金属银.所制备的银纳米粒子对大肠杆菌和金黄色葡萄球菌作抑菌性试验.%The use of Rhodopseudomonas palustris in biosynthesis of silver nanoparticles (AgNPs) emerges as a reliable and eco-friendly approach in recent years. This report focuses on extracellular biosynthesis of AgNPs using cell filtrate of Rhodopseudomonas palustris. These nanoparticles were characterized by UV-vis spectrum, X-ray diffraction (XRD) spectrum and transmission electron microscopy (TEM). UV-vis spectrum of the aqueous medium containing silver ion showed a peak between 420 nm-460 nm corresponding to the plasmon absorbance of AgNPs. TEM micrograph showed formation of the AgNPs in the range of 5 nm-20 nm. XRD of the nanoparticles confirmed the formation of metallic silver. The AgNPs were evaluated for their antimicrobial activities against Escherichia coli and Staphyloccocus aureus.

  4. Prevalence of Staphylococcus aureus and Methicillin-Resistant Staphylococcus aureus in Retail Ready-to-Eat Foods in China.

    Science.gov (United States)

    Yang, Xiaojuan; Zhang, Jumei; Yu, Shubo; Wu, Qingping; Guo, Weipeng; Huang, Jiahui; Cai, Shuzhen

    2016-01-01

    Staphylococcus aureus, particularly methicillin-resistant S.aureus (MRSA), is a life-threatening pathogen in humans, and its presence in food is a public health concern. MRSA has been identified in foods in China, but little information is available regarding MRSA in ready-to-eat (RTE) foods. We aimed to investigate the prevalence of S. aureus and MRSA in Chinese retail RTE foods. All isolated S. aureus were tested for antimicrobial susceptibility, and MRSA isolates were further characterized by multilocus sequence typing (MLST) and staphylococcal cassette chromosome mec (SCCmec) typing. Of the 550 RTE foods collected from 2011 to 2014, 69 (12.5%) were positive for S. aureus. Contamination levels were mostly in the range of 0.3-10 most probable number (MPN)/g, with five samples exceeding 10 MPN/g. Of the 69 S. aureus isolates, seven were identified as MRSA by cefoxitin disc diffusion test. Six isolates were mecA-positive, while no mecC-positive isolates were identified. In total, 75.8% (47/62) of the methicillin-susceptible S. aureus isolates and all of the MRSA isolates were resistant to three or more antibiotics. Amongst the MRSA isolates, four were identified as community-acquired strains (ST59-MRSA-IVa (n = 2), ST338-MRSA-V, ST1-MRSA-V), while one was a livestock-associated strain (ST9, harboring an unreported SCCmec type 2C2). One novel sequence type was identified (ST3239), the SCCmec gene of which could not be typed. Overall, our findings showed that Chinese retail RTE foods are likely vehicles for transmission of multidrug-resistant S. aureus and MRSA lineages. This is a serious public health risk and highlights the need to implement good hygiene practices.

  5. Antioxidant and antimicrobial activities of Shorea kunstleri

    Institute of Scientific and Technical Information of China (English)

    Siti Suria Daud; Muhammad Taher; Deny Susanti

    2014-01-01

    Objective:To evaluate antioxidant and antimicrobial activities of stembark of Shorea kunstleri (S. kunstleri) together with analysis of phytochemical and total phenolic contents. Methods:Extraction was conducted with different solvent polarity of n-hexane, dichloromethane (DCM) and methanol by using Soxhlet extraction. Total phenolic content was determined using Folin-Ciocalteu method. Free radical scavenging activity and inhibition of lipid peroxidation were evaluated with DPPH radical scavenging and ferric thiocyanate assays, respectively. Antimicrobial activities were performed using disc diffusion method, minimum inhibition concentration (MIC), minimum bactericidal concentration (MBC), and minimum fungicidal concentration. Results:S. kunstleri stembark extracts revealed presence of steroids, terpenoids, saponins, flavonoids, and phenolic compounds. Methanol extract exhibited the highest total phenolic content and free radical scavenging activity resulting in phenolic content of (8.340±0.003) g GAE/100 g of extract and (95.90±1.07)% DPPH inhibition (IC50 value of 18.6 µg/mL), respectively. Ferric thiocyanate assay of n-hexane, DCM, and methanol extracts indicated lipid peroxidation inhibitory activity of (74.20±0.35)%, (74.00±0.10)%, and (72.80±0.27)%, respectively. In antimicrobial and antifungal tests, methanol extract showed inhibition against Staphylococcus aureus (S. aureus), Candida albicans, and Candida tropicalis with inhibition zones of 10-12, 18-22, and 18-19 mm, respectively. The MIC test of methanol extract showed highest inhibition against Candida albicans and S. aureus (0.04 and 0.08 mg/mL, respectively) while DCM extract exhibited the highest activity towards Candida tropicalis (MIC value of 0.63 mg/mL). Taken together, MBC test of methanol extract strongly demonstrated bactericidal effect against S. aureus with MBC value of 0.08 mg/mL. Conclusions:The study demonstrated that stembark extracts of S. kunstleri possessed antioxidant and

  6. Hypoxic radiosensitization by the antimicrobial methyl paraben

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, G.P.; Sade, N.

    1984-08-01

    The antimicrobial preservative, methyl paraben (methyl-4-hydroxybenzoate) sensitizes anoxic buffered suspensions of Staphylococcus aureus to gamma-radiation. The maximal response at an 0.5 mM concentration represents a 150 percent increase in response over that for deoxygenated suspensions without additive, and 80 percent of the response for aerated suspensions alone. Methyl paraben is not toxic to the test organism under the present test conditions.

  7. Antioxidant and antimicrobial activities of Shorea kunstleri

    Directory of Open Access Journals (Sweden)

    Siti Suria Daud

    2014-08-01

    Full Text Available Objective: To evaluate antioxidant and antimicrobial activities of stembark of Shorea kunstleri (S. kunstleri together with analysis of phytochemical and total phenolic contents. Methods: Extraction was conducted with different solvent polarity of n-hexane, dichloromethane (DCM and methanol by using Soxhlet extraction. Total phenolic content was determined using Folin-Ciocalteu method. Free radical scavenging activity and inhibition of lipid peroxidation were evaluated with DPPH radical scavenging and ferric thiocyanate assays, respectively. Antimicrobial activities were performed using disc diffusion method, minimum inhibition concentration (MIC, minimum bactericidal concentration (MBC, and minimum fungicidal concentration. Results: S. kunstleri stembark extracts revealed presence of steroids, terpenoids, saponins, flavonoids, and phenolic compounds. Methanol extract exhibited the highest total phenolic content and free radical scavenging activity resulting in phenolic content of (8.340±0.003 g GAE/100 g of extract and (95.90±1.07% DPPH inhibition (IC50 value of 18.6 µg/mL, respectively. Ferric thiocyanate assay of n-hexane, DCM, and methanol extracts indicated lipid peroxidation inhibitory activity of (74.20±0.35%, (74.00±0.10%, and (72.80±0.27%, respectively. In antimicrobial and antifungal tests, methanol extract showed inhibition against Staphylococcus aureus (S. aureus, Candida albicans, and Candida tropicalis with inhibition zones of 10-12, 18-22, and 18-19 mm, respectively. The MIC test of methanol extract showed highest inhibition against Candida albicans and S. aureus (0.04 and 0.08 mg/mL, respectively while DCM extract exhibited the highest activity towards Candida tropicalis (MIC value of 0.63 mg/mL. Taken together, MBC test of methanol extract strongly demonstrated bactericidal effect against S. aureus with MBC value of 0.08 mg/mL. Conclusions: The study demonstrated that stembark extracts of S. kunstleri possessed antioxidant

  8. CHARACTERISTIC OF SENSITIVITY OF STAPHYLOCOCCUS AUREUS AND CANDIDA ALBICANS TO ANTIBACTERIAL PREPARATIONS AND COLLOIDAL SILVER

    OpenAIRE

    Afonina, I A; L. A. Kraeva; G. Y. Tseneva

    2011-01-01

    Abstract. Constant use of antibiotics leads to reliable increasing of resistance among microorganisms. Using non-toxic concentrations of colloidal silver in combination with antimicrobial agents can reduce using concentrations of antibiotics, kept necessary antimicrobial effect. In case of Staphylococcus aureus bactericidal activity of the complex of colloidal silver with unit concentration of neomycin is bigger than the bactericidal effect of double concentration of the antibiotic. Fungicida...

  9. Influence of Magnolol on the Secretion of α-Toxin by Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Xu-Ming Deng

    2010-03-01

    Full Text Available In this study we investigated the antimicrobial activity of magnolol on Staphylococcus aureus. The minimal inhibitory concentrations of magnolol against 31 S. aureus strains ranged from 4–32 μg/mL. In addition, hemolysin assays, Western blotting, and real-time RT-PCR were performed to investigate the effect of magnolol on α-toxin secretion by both methicillin-sensitive S. aureus (MSSA and methicillin-resistant S. aureus (MRSA. The results indicated that sub-inhibitory concentrations of magnolol dose-dependently inhibited the transcription of hla (the gene encoding α-toxin in S. aureus, resulting in a reduction of α-toxin secretion and, thus, hemolytic activities.

  10. [Optimisation of the antibiotic policy in the Netherlands. XII. The SWAB guideline for antimicrobial eradication of MRSA in carriers].

    NARCIS (Netherlands)

    Wertheim, H.F.; Ammerlaan, H.S.; Bonten, M.J.; Broek, P.J.J.A. van den; Troelstra, A.; Vandenbroucke-Grauls, C.M.; Vos, M.C.; Voss, A.; Nouwen, J.L.; Kluytmans, J.A.

    2008-01-01

    The 'Stichting Werkgroep Antibioticabeleid' (SWAB; Dutch Working Party on Antibiotics Policy) has developed evidence-based guidelines for the antimicrobial treatment of methicillin-resistant Staphylococcus aureus (MRSA) carriers for the eradication of MRSA. A distinction was made between uncomplicat

  11. ANTIMICROBIAL ACTIVITY OF EXTRACTS FROM ECUADORIAN LICHENS.

    Science.gov (United States)

    Matvieieva, N A; Pasichnyk, L A; Zhytkevych, N V; Jacinto, Pabón Garcés Galo; Pidgorskyi, V S

    2015-01-01

    Antimicrobial activity of the ethanolic, isopropanolic, acetone, DMSO and aqueous extracts of the two lichen species from Ecuadorian highland, Usnea sp. and Stereocaulon sp. were explored in vitro against bacteria Bacillus subtilis, Escherichia coli and Staphylococcus aureus by the disc-diffusion method. Also the minimal inhibitory concentration (MIC) was determined. The strongest antimicrobial activity was found in DMSO extract of Usnea sp. compared to antibacterial activity of ciprfloxacin and cefazolin antibiotics. The inhibition zone was 28 mm, 30 mm, 31mm (DMSO extract, ciprfloxacin and cefazolin respectively) in case of B. subtilis usage as the test bacteria. MIC value for Usnea sp. and Stereocaulon sp. DMSO extracts was 0.4 mg/ml. E. coli was resistant to all kinds of extracts. The S. aureus sensitivity to lichen DMSO extracts was comparable to sensitivity of these microorganisms to tetracycline and vancomycin. Thereby, most kinds of extracts (ethanol, isopropanol, hexane, DMSO and acetone solvents) from Ecuadorian lichens Usnea sp. and Stereocaulon sp. with the exception of aqueous Stereocaulon sp. extracts possessed antibacterial activity against B. subtilis. DMSO lichen extracts had also antimicrobial activity against S. aureus. At the same time the extracts studied didn't demonstrate antibacterial activity against the representatives of the most common and harmful phytopathogenic bacteria tested. Further investigations of Ecuadorian lichens especially study of plants collected from extremal highland biotops can be very important in study of possibility of treatment of numerous diseases caused by pathogenic microorganisms.

  12. Electrospun mats from styrene/maleic anhydride copolymers: modification with amines and assessment of antimicrobial activity.

    Science.gov (United States)

    Ignatova, Milena; Stoilova, Olya; Manolova, Nevena; Markova, Nadya; Rashkov, Iliya

    2010-08-11

    New antimicrobial microfibrous electrospun mats from styrene/maleic anhydride copolymers were prepared. Two approaches were applied: (i) grafting of poly(propylene glycol) monoamine (Jeffamine® M-600) on the mats followed by formation of complex with iodine; (ii) modification of the mats with amines of 8-hydroxyquinoline or biguanide type with antimicrobial activity. Microbiological screening against S. aureus, E. coli and C. albicans revealed that both the formation of complex with iodine and the covalent attachment of 5-amino-8-hydroxyquinoline or of chlorhexidine impart high antimicrobial activity to the mats. In addition, S. aureus bacteria did not adhere to modified mats.

  13. Comparative assessment of antimicrobial efficacy of different hand sanitizers: An in vitro study

    OpenAIRE

    Jain, Vardhaman Mulchand; Karibasappa, Gundabaktha Nagappa; Dodamani, Arun Suresh; Prashanth, Vishwakarma K.; Mali, Gaurao Vasant

    2016-01-01

    Background: To evaluate the antimicrobial efficacy of four different hand sanitizers against Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Escherichia coli, and Enterococcus faecalis as well as to assess and compare the antimicrobial effectiveness among four different hand sanitizers. Materials and Methods: The present study is an in vitro study to evaluate antimicrobial efficacy of Dettol, Lifebuoy, PureHands, and Sterillium hand sanitizers against clinical isola...

  14. Comparative assessment of antimicrobial efficacy of different hand sanitizers: An in vitro study

    OpenAIRE

    Vardhaman Mulchand Jain; Gundabaktha Nagappa Karibasappa; Arun Suresh Dodamani; Prashanth, Vishwakarma K.; Gaurao Vasant Mali

    2016-01-01

    Background: To evaluate the antimicrobial efficacy of four different hand sanitizers against Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Escherichia coli, and Enterococcus faecalis as well as to assess and compare the antimicrobial effectiveness among four different hand sanitizers. Materials and Methods: The present study is an in vitro study to evaluate antimicrobial efficacy of Dettol, Lifebuoy, PureHands, and Sterillium hand sanitizers against clinical i...

  15. Small Colony variants of Staphylococcus aureus isolated from a patient with infective endocarditis: a case report and review of the literature

    Directory of Open Access Journals (Sweden)

    Sayan Bhattacharyya

    2012-06-01

    Full Text Available Staphylococcus aureus produces a particular morphological variant called small colony variant(SCV which is responsible for persistent subclinical infections in predisposed individuals and is usually resistant to aminoglycosides and cell wall active antibiotics. Infections by SCV of S. aureus is an upcoming problem due to difficulty in laboratory diagnosis and resistance to antimicrobial chemotherapy. We here report a case of infective endocarditis caused by SCV of Staphylococcus aureus in a pediatric patient.

  16. Screening a Commercial Library of Pharmacologically Active Small Molecules against Staphylococcus aureus Biofilms.

    Science.gov (United States)

    Torres, Nelson S; Abercrombie, Johnathan J; Srinivasan, Anand; Lopez-Ribot, Jose L; Ramasubramanian, Anand K; Leung, Kai P

    2016-10-01

    It is now well established that bacterial infections are often associated with biofilm phenotypes that demonstrate increased resistance to common antimicrobials. Further, due to the collective attrition of new antibiotic development programs by the pharmaceutical industries, drug repurposing is an attractive alternative. In this work, we screened 1,280 existing commercially available drugs in the Prestwick Chemical Library, some with previously unknown antimicrobial activity, against Staphylococcus aureus, one of the commonly encountered causative pathogens of burn and wound infections. From the primary screen of the entire Prestwick Chemical Library at a fixed concentration of 10 μM, 104 drugs were found to be effective against planktonic S. aureus strains, and not surprisingly, these were mostly antimicrobials and antiseptics. The activity of 18 selected repurposing candidates, that is, drugs that show antimicrobial activity that are not already considered antimicrobials, observed in the primary screen was confirmed in dose-response experiments. Finally, a subset of nine of these drug candidates was tested against preformed biofilms of S. aureus We found that three of these drugs, niclosamide, carmofur, and auranofin, possessed antimicrobial activity against preformed biofilms, making them attractive candidates for repurposing as novel antibiofilm therapies.

  17. Minimum inhibitory concentration of ciprofloxacin in combination with hexahydroquinoline derivatives against Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    F Amin Harati

    2012-12-01

    Full Text Available Background: Staphylococcus aureus is the most common pathogen responsible for skin and soft tissue infections worldwide. Methicillin-resistant S. aureus is a major cause of both nosocomial and community acquired infections. The emergence of antimicrobial-resistant S. aureus is of global concern. Fluoroquinolone antimicrobials including ciprofloxacin, levofloxacin, and moxifloxacin are used to treat skin and soft tissue infections due to S. aureus. Emergence of ciprofloxacin resistance has increased in community acquired methicillin-resistant S. aureus strains. The aim of this study was to evaluate the minimum inhibitory concentration of ciprofloxacin and hexahydroquino-line derivatives against methicillin- and ciprofloxacin-resistant S. aureus.Methods: Identification of S. aureus was performed by routine microbiological tests in the Department of Pathobiology in Winter 2012. The susceptibility of S. aureus strains to both methicillin and ciprofloxacin was examined by the Kirby-Bauer disk-diffusion method. The minimum inhibitory concentration of ciprofloxacin, hexahydroquinoline derivatives and their combination were separately determined by broth microdilution method against methicillin- and ciprofloxacin-resistant S. aureus.Results: The minimum inhibitory concentration of ciprofloxacin decreased in the presence of hexahydroquinolinein derivatives in comparison with ciprofloxacin alone.Conclusion: This study showed that hexahydroquinoline derivatives enhance the antibacterial effect of ciprofloxacin against methicillin- and ciprofloxacin-resistant S. aureus. Therefore, these derivatives could be used as inhibitors of antibiotic resistance in combination therapies. This enhancement may be related to the inhibitory effect of hexahydroquinoline derivatives on the expression of antibiotic efflux pump in the bacteria. However, the structural features of a fluoroquinolone that determine whether it is affected by efflux transporters are not fully

  18. Novel high efficient coatings for anti-microbial surgical sutures using chlorhexidine in fatty acid slow-release carrier systems.

    Directory of Open Access Journals (Sweden)

    Andreas Obermeier

    Full Text Available Sutures can cause challenging surgical site infections, due to capillary effects resulting in bacteria permeating wounds. Anti-microbial sutures may avoid these complications by inhibiting bacterial pathogens. Recently, first triclosan-resistances were reported and therefore alternative substances are becoming clinically relevant. As triclosan alternative chlorhexidine, the "gold standard" in oral antiseptics was used. The aim of the study was to optimize novel slow release chlorhexidine coatings based on fatty acids in surgical sutures, to reach a high anti-microbial efficacy and simultaneously high biocompatibility. Sutures were coated with chlorhexidine laurate and chlorhexidine palmitate solutions leading to 11, 22 or 33 µg/cm drug concentration per length. Drug release profiles were determined in aqueous elutions. Antibacterial efficacy against Staphylococcus aureus was assessed in agar diffusion tests. Biocompatibility was evaluated via established cytotoxicity assay (WST-1. A commercially triclosan-containing suture (Vicryl Plus, was used as anti-microbial reference. All coated sutures fulfilled European Pharmacopoeia required tensile strength and proved continuous slow drug release over 96 hours without complete wash out of the coated drug. High anti-microbial efficacy for up to 5 days was observed. Regarding biocompatibility, sutures using 11 µg/cm drug content displayed acceptable cytotoxic levels according to ISO 10993-5. The highest potential for human application were shown by the 11 µg/cm chlorhexidine coated sutures with palmitic acid. These novel coated sutures might be alternatives to already established anti-microbial sutures such as Vicryl Plus in case of triclosan-resistance. Chlorhexidine is already an established oral antiseptic, safety and efficacy should be proven for clinical applications in anti-microbial sutures.

  19. Characterization of toxin genes and antimicrobial resistance of Staphylococcus aureus isolated from pork%猪肉源金黄色葡萄球菌毒力基因检测与耐药性分析

    Institute of Scientific and Technical Information of China (English)

    陶晓亚; 徐明悦; 王新; 周婷; 夏效东; 杨保伟; 席美丽; 孟江洪

    2013-01-01

    [目的]了解陕西关中地区猪肉中金黄色葡萄球菌(Staphylococcus aureus)的污染状况、耐药性及其毒素基因的分布.[方法]采集陕西关中6个地区的猪肉165份,按国标GB/T 4789.10-2010的方法,对其中的金黄色葡萄球菌进行分离,采用PCR方法对该菌进行确证并对其相关基因(如nuc、mecA、PVL、SEs和ETs)进行检测,最后采用琼脂稀释法检测金黄色葡萄球菌对11种抗菌药物的耐药性.另外,在BP平板中分别添加头孢西丁(4μg/mL)和苯唑西林(4μg/mL),分离耐甲氧西林金黄色葡萄球菌(MRSA).[结果]165份样品的金黄色葡萄球菌污染率为33.33%(55/165);从中分离出103株金黄色葡萄球菌,但未检测出MRSA,这些菌对甲氧苄啶的耐药性最强,耐药率为100%;其次对红霉素和四环素的耐药率较高,分别为57.28%和34.95%;对苯唑西林、庆大霉素、氯霉素、环丙沙星的耐药率分别为2.91%,10.68%,2.91%和3.88%;所有菌株对头孢西丁、头孢哌酮、万古霉素、阿米卡星均敏感,同时得到21种耐药谱,多重耐药率达20.39%.猪肉金黄色葡萄球菌中杀白细胞素基因(Panton-valentine leukocidin,PVL)的检出率为34.95%,肠毒素基因(SEs)中sej的检出率最高,为98.06%,然后依次为sea(50.49%)、see(34.95%)、sed(31.07%)、sec(13.59%)、seh(8.74%)、sei(8.74%)、seg(6.80%)和seb(1.94%);同时得到71种毒素基因型,以sea+sej(11.65%)最为流行,分布地区不尽相同,其次为PVL+sea+see+sej(9.71%),耐红霉素的金黄色葡萄球菌含的毒素基因类型比较复杂,sej基因检出率高达98.68%.在BP平板中分别添加头孢西丁和苯唑西林,均未检测出MRSA.[结论]猪肉存在金黄色葡萄球菌的污染,其污染菌株存在多重耐药性并携带较多毒素基因,提示应加强猪肉金黄色葡萄球菌的监测.在BP平板中分别添加头孢西丁(4 μg/mL)和苯唑西林(4μg/mL)筛选MRSA的方法不一定可靠,其可信度有待证明.

  20. Antimicrobial hyperbranched poly(ester amide)/polyaniline nanofiber modified montmorillonite nanocomposites.

    Science.gov (United States)

    Pramanik, Sujata; Bharali, Pranjal; Konwar, B K; Karak, Niranjan

    2014-02-01

    There has been growing interest in the use of nanomaterials featuring potent of antimicrobial activity in the biomedical domain. It still remains a challenge for the researchers to develop an efficient nanocomposite possessing antimicrobial efficacy against broad spectrum microbes including bacteria, fungi as well as algal consortium, posing serious challenges for the human survival. In addressing the above problem, we report the fabrication of bio-based hyperbranched poly(ester amide) (HBPEA)/polyaniline nanofiber modified montmorillonite (MMT) nanocomposites by an ex-situ polymerization technique at varied weight percentages (1, 2.5, 5 wt.%) of the modified MMT (nanohybrid). The Fourier transform infrared spectroscopy confirmed the structural changes upon interaction of the nanohybrid with HBPEA. A probable mechanism is proposed for the formation of nanocomposites with partially exfoliated nanoplatelet structure, which was further confirmed from the high resolution transmission electron microscopic analyses. The prepared nanocomposites exhibited potent efficacy against gram positive bacteria like Bacillus subtilis and Staphylococcus aureus as compared to the gram negative ones like Pseudomonas aeruginosa and Escherichia coli. The nanocomposites showed significant antifungal activity against Aspergillus niger, Fusarium oxysporum and Coleotricum capcii and antialgal activity against algal consortium comprising of Chlorella, Hormidium and Cladophorella species. The formation of thermosetting nanocomposites resulted in the acceptable improvement of desired physico-chemical and mechanical properties including thermostability. Thus pronounced antimicrobial activity of the nanocomposites against a spectrum of bacterial and fungal strains as well as a consortium of algal species along with other desired performance vouched them as potent antimicrobial materials in the realm of health and biomedical industry.

  1. Design, synthesis and antimicrobial evaluation of novel carbendazim dithioate analogs

    DEFF Research Database (Denmark)

    Zahran, Magdy A H; Osman, Amany M A; Wahed, Rania A.;

    2015-01-01

    -spectroscopy. All the synthesized carbendazim analogs were screened for their in vitro antimicrobial activity against different Gram-positive (Staphylococcus aureus and Micrococcus luteus), Gram-negative (Escherichia coli and Klebsiella pneumonia) bacteria, fungi (Fusarium solani and Fusarium oxysporu) and in vivo...

  2. Antimicrobial Activity of the Lichen Cetraria islandica (L.) Ach.

    OpenAIRE

    Başaran DÜLGER; GÜCİN, Fahrettin

    1998-01-01

    In this study, extracts of Cetraria islandica (L.) Ach. were prepared with Ethyl acetate, Acetone, Chloroform and Ethanol and antimicrobial activities of these extracts were examined on test microorganisms as follows: Escherichia coli ATCC 11230, Enterobacter aerogenes CCM 2531, Staphylococcus aureus 6538P, Staphylococcus epidermidis, Bacillus subtilis La2114, Bacillus cereus var. mycoides, Bacillus sphaericus, Bacillus thurigiensis, Bacillus megaterium, Mycobacterium smegmatis RUT, Salmo...

  3. 原料乳和临床乳房炎金黄色葡萄球菌毒力基因检测及药敏分析%Characterization of toxin genes and antimicrobial susceptibility of Staphylococcus aureus isolated from raw milk and milk of clinical mastitis

    Institute of Scientific and Technical Information of China (English)

    张静; 于三科; 王新; 孙全才

    2012-01-01

    乳房炎加以重视。%A total of 101 Staphylococcus aureus isolates from raw milk(44 isolates) and milk of clinical mastitis(57 isolates) were tested,for the prevalence of nine enterotoxin and four other exotoxin genes by polymerase chain reaction and antimicrobial susceptibility testing by the agar dilution method.It shows that in the 44 strains of S.aureus from raw milk,84.09% were positive for one or more toxin genes,84.09% isolates harbored PVL gene,52.27% isolates harbored one or more SE genes,and sea(56.82%) was the most common pattern,mecA,ETs,TSST-1 sei and sej genes were not detected.Resistance was most frequently observed to trimethoprim(100%),followed by cefoxitin(86.36%),chloramphenicol(11.36%),erythromycin(4.55%),oxacillin(2.27%),cefoperazone(2.27%) and gentamicin(6.82%).All S.aureus isolates from raw milk were susceptible to amikacin,ciprofloxacin and vancomycin.Of the 57 strains of S.aureus from milk of clinical mastitis,78.95% were positive for one or more toxin genes,28.07% isolates harbored PVL gene,77.19% isolates harbored one or more SE genes,and sea(47.37%) was the most common pattern,10.53% mecA gene was detected,ETs,TSST-1 and seh genes were not detected.Resistance was most frequently observed to erythromycin(100%),followed by trimethoprim(71.93%),chloramphenicol(28.07%),gentamicin(26.07%),ciprofloxacin(24.56%),cefoxitin(19.30%) and oxacillin(7.02%).All isolates of S.aureus from milk of clinical mastitis were susceptible to amikacin,cefoperazone,vancomycin and tetracycline.Many S.aureus isolates from raw milk and milk of clinical mastitis contained different multiple resistance and various toxin genes,MRSA was only isolated from cows with clinical mastitis.Our results may provide useful information for assessment of the possible risk posed to milk products.

  4. Staphylococcus aureus bacteremia.

    Science.gov (United States)

    Jensen, Allan Garlik

    2003-11-01

    Staphylococcus aureus bacteremia (SAB) is still associated with a high mortality, and knowledge on risk factors and the clinical and the therapeutic aspects of SAB is still limited. This thesis focuses on the clinical aspects of SAB and its metastatic infections. In a study of all patients with bacteremia in Copenhagen County October 1992 through April 1993 (study I) we emphasized previous findings, that S. aureus is one of the most frequent pathogens in bacteremia, and in a case control study also in Copenhagen County 1994-95 (study II) we demonstrated, that not only an inserted central venous catheter and nasal S. aureus carriage but also hyponatremia and anemia are important risk factors for hospital-acquired SAB (study II). Studies on the treatment of SAB have pointed out, that the eradication of a primary is important, but there are only limited clinical studies dealing with antibiotic treatment. By logistic regression analysis, we were able to demonstrate that focus eradication is essential, but also that treatment with dicloxacillin 1 g x 4 or 2 g x 3 are superior to 1 g x 3 (studie III), indicating that the time for serum concentration above the Minimal Inhibitory Concentration (MIC) for the bacteria plays a role in the outcome of SAB treatment. S. aureus osteomyelitis secondary to SAB is frequently observed. No other countries, however, have a centralized registration, which make it possible to evaluate a large number of these patients. Since 1960, The Staphylococcal Laboratory, Statens Serum Institut in Copenhagen, has registrated selected clinical informations from nearly all patients with positive blood cultures of S. aureus. Based on this registration, we were able to show an increased number of S. aureus osteomyelitis among older patients and a decreased number of S. aureus osteomyelitis of femur and tibia among younger infants in the period 1980-90 (study IV). By reviewing the records of a large number of patients with vertebral S. aureus

  5. Heavy metal and disinfectant resistance genes among livestock-associated methicillin-resistant Staphylococcus aureus isolates

    DEFF Research Database (Denmark)

    Argudin, Maria Angeles; Lauzat, Birgit; Kraushaar, Britta;

    2016-01-01

    Livestock associated methicillin-resistant Staphylococcus aureus (LA-MRSA) has emerged in animal production worldwide. Most LA-MRSA in Europe belong to the clonal complex (CC)398. The reason for the LA-MRSA emergence is not fully understood. Besides antimicrobial agents used for therapy, other su...

  6. The clinical impact of methicillin-resistant Staphylococcus aureus on morbidity, mortality and burden of disease

    NARCIS (Netherlands)

    Ammerlaan, H.S.M.

    2010-01-01

    The aim of this thesis was to evaluate the clinical impact of methicillin-resistant Staphylococcus aureus [MRSA] infections on the total burden of disease. A guideline on empirical antimicrobial eradication of MRSA in carriers was developed based on a systematic review of literature. A distinction w

  7. Heterogeneity among methicillin-resistant Staphylococcus aureus from Italian pig finishing holdings

    DEFF Research Database (Denmark)

    Battisti, A.; Franco, A.; Merialdi, G.;

    2010-01-01

    A survey for methicillin-resistant Staphylococcus aureus (MRSA) in finishing pig holdings was carried out in Italy in 2008. MRSA isolates were characterised by spa-. SCCmec- and antimicrobial susceptibility typing. A prevalence of 38% (45/118, 95% CI 29.4-46.9%) positive holdings was observed...

  8. The effectiveness of bacteriophages against methicillin-resistant Staphylococcus aureus ST398 nasal colonization in pigs

    NARCIS (Netherlands)

    Verstappen, Koen M.; Tulinski, Pawel; Duim, Birgitta; Fluit, Ad C.; Carney, Jennifer; Nes, Van Arie; Wagenaar, Jaap A.

    2016-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is an important colonizer in animals and an opportunistic pathogen in humans. In humans, MRSA can cause infections that might be difficult to treat because of antimicrobial resistance. The use of bacteriophages has been suggested as a potential a

  9. Draft Genome Sequence of the Aureocin A53–Producing Strain Staphylococcus aureus A53

    Science.gov (United States)

    Santos, Olinda Cabral Silva; Duarte, Andreza Freitas Souza; Albano, Rodolpho Mattos

    2016-01-01

    Here, we present the 2,658,363-bp draft genome sequence of the aureocin A53–producing strain Staphylococcus aureus A53. This genome information may contribute to the optimal and rational exploitation of aureocin A53 as an antimicrobial agent and to its production in large scale. PMID:27563042

  10. Draft Genome Sequence of the Aureocin A53-Producing Strain Staphylococcus aureus A53.

    Science.gov (United States)

    Santos, Olinda Cabral Silva; Duarte, Andreza Freitas Souza; Albano, Rodolpho Mattos; Bastos, Maria Carmo Freire

    2016-08-25

    Here, we present the 2,658,363-bp draft genome sequence of the aureocin A53-producing strain Staphylococcus aureus A53. This genome information may contribute to the optimal and rational exploitation of aureocin A53 as an antimicrobial agent and to its production in large scale.

  11. Antimicrobial resistance in Libya: 1970-2011.

    Science.gov (United States)

    Ghenghesh, Khalifa Sifaw; Rahouma, Amal; Tawil, Khaled; Zorgani, Abdulaziz; Franka, Ezzedin

    2013-03-27

    Resistance to antimicrobial agents is a major health problem that affects the whole world. Providing information on the past state of antimicrobial resistance in Libya may assist the health authorities in addressing the problem more effectively in the future. Information was obtained mainly from Highwire Press (including PubMed) search for the period 1970-2011 using the terms 'antibiotic resistance in Libya', 'antimicrobial resistance in Libya', 'tuberculosis in Libya', and 'primary and acquired resistance in Libya' in title and abstract. From 1970 to 2011 little data was available on antimicrobial resistance in Libya due to lack of surveillance and few published studies. Available data shows high resistance rates for Salmonella species in the late 1970s and has remained high to the present day. High prevalence rates (54-68%) of methicillin-resistant Staphylococcus aureus (MRSA) were reported in the last decade among S. aureus from patients with burns and surgical wound infections. No reports were found of vancomycin-resistant S. aureus (VRSA) or vancomycin-intermediate-resistant S. aureus (VISA) using standard methods from Libya up to the end of 2011. Reported rates of primary (i.e. new cases) and acquired (i.e. retreatment cases) multidrug-resistant tuberculosis (MDR-TB) from the eastern region of Libya in 1971 were 16.6 and 33.3% and in 1976 were 8.6 and 14.7%, in western regions in 1984-1986 were 11 and 21.5% and in the whole country in 2011 were estimated at 3.4 and 29%, respectively. The problem of antibiotic resistance is very serious in Libya. The health authorities in particular and society in general should address this problem urgently. Establishing monitoring systems based on the routine testing of antimicrobial sensitivity and education of healthcare workers, pharmacists, and the community on the health risks associated with the problem and benefits of prudent use of antimicrobials are some steps that can be taken to tackle the problem in the future.

  12. Effect of Catechins, Green tea Extract and Methylxanthines in Combination with Gentamicin Against Staphylococcus aureus and Pseudomonas aeruginosa - Combination therapy against resistant bacteria -

    Directory of Open Access Journals (Sweden)

    Bibi Sedigheh Fazly Bazzaz

    2016-12-01

    Full Text Available Objectives: Bacterial resistant infections have become a global health challenge and threaten the society’s health. Thus, an urgent need exists to find ways to combat resistant pathogens. One promising approach to overcoming bacterial resistance is the use of herbal products. Green tea catechins, the major green tea polyphenols, show antimicrobial activity against resistant pathogens. The present study aimed to investigate the effect of catechins, green tea extract, and methylxanthines in combination with gentamicin against standard and clinical isolates of Staphylococcus aureus (S. aureus and the standard strain of Pseudomonas aeruginosa (P. aeruginosa. Methods: The minimum inhibitory concentration (MIC and the minimum bactericidal concentration (MBC values of different agents against bacterial strains were determined. The interactions of green tea extract, epigallate catechin, epigallocatechin gallate, two types of methylxanthine, caffeine, and theophylline with gentamicin were studied in vitro by using a checkerboard method and calculating the fraction inhibitory concentration index (FICI. Results: The MICs of gentamicin against bacterial strains were in the range of 0.312 - 320 μg/mL. The MIC values of both types of catechins were 62.5 - 250 μg/ mL. Green tea extract showed insufficient antibacterial activity when used alone. Methylxanthines had no intrinsic inhibitory activity against any of the bacterial strains tested. When green tea extract and catechins were combined with gentamicin, the MIC values of gentamicin against the standard strains and a clinical isolate were reduced, and synergistic activities were observed (FICI < 1. A combination of caffeine with gentamicin did not alter the MIC values of gentamicin. Conclusion: The results of the present study revealed that green tea extract and catechins potentiated the antimicrobial action of gentamicin against some clinical isolates of S. aureus and standard P. aeruginosa strains

  13. Neutrophil-generated oxidative stress and protein damage in Staphylococcus aureus.

    Science.gov (United States)

    Beavers, William N; Skaar, Eric P

    2016-08-01

    Staphylococcus aureus is a ubiquitous, versatile and dangerous pathogen. It colonizes over 30% of the human population, and is one of the leading causes of death by an infectious agent. During S. aureus colonization and invasion, leukocytes are recruited to the site of infection. To combat S. aureus, leukocytes generate an arsenal of reactive species including superoxide, hydrogen peroxide, nitric oxide and hypohalous acids that modify and inactivate cellular macromolecules, resulting in growth defects or death. When S. aureus colonization cannot be cleared by the immune system, antibiotic treatment is necessary and can be effective. Yet, this organism quickly gains resistance to each new antibiotic it encounters. Therefore, it is in the interest of human health to acquire a deeper understanding of how S. aureus evades killing by the immune system. Advances in this field will have implications for the design of future S. aureus treatments that complement and assist the host immune response. In that regard, this review focuses on how S. aureus avoids host-generated oxidative stress, and discusses the mechanisms used by S. aureus to survive oxidative damage including antioxidants, direct repair of damaged proteins, sensing oxidant stress and transcriptional changes. This review will elucidate areas for studies to identify and validate future antimicrobial targets.

  14. Antibacterial Activity of New Oxazolidin-2-One Analogues in Methicillin-Resistant Staphylococcus aureus Strains

    Directory of Open Access Journals (Sweden)

    Jesús Córdova-Guerrero

    2014-03-01

    Full Text Available Staphylococcus aureus is one of the most common causes of nosocomial infections. The purpose of this study was the synthesis and in vitro evaluation of antimicrobial activity of 10 new 3-oxazolidin-2-one analogues on 12 methicillin resistant S. aureus (MRSA clinical isolates. S. aureus confirmation was achieved via catalase and coagulase test. Molecular characterization of MRSA was performed by amplification of the mecA gene. Antimicrobial susceptibility was evaluated via the Kirby-Bauer disc diffusion susceptibility test protocol, using commonly applied antibiotics and the oxazolidinone analogues. Only (R-5-((S-1-dibenzylaminoethyl-1,3-oxazolidin-2-one (7a exhibited antibacterial activity at 6.6 μg. These results, allow us to infer that molecules such as 7a can be potentially used to treat infections caused by MRSA strains.

  15. Antibacterial Activity of New Oxazolidin-2-One Analogues in Methicillin-Resistant Staphylococcus aureus Strains

    Science.gov (United States)

    Córdova-Guerrero, Jesús; Hernández-Guevara, Esteban; Ramírez-Zatarain, Sandy; Núñez-Bautista, Marco; Ochoa-Terán, Adrián; Muñiz-Salazar, Raquel; Montes-Ávila, Julio; López-Angulo, Gabriela; Paniagua-Michel, Armando; Nuño Torres, Gustavo A.

    2014-01-01

    Staphylococcus aureus is one of the most common causes of nosocomial infections. The purpose of this study was the synthesis and in vitro evaluation of antimicrobial activity of 10 new 3-oxazolidin-2-one analogues on 12 methicillin resistant S. aureus (MRSA) clinical isolates. S. aureus confirmation was achieved via catalase and coagulase test. Molecular characterization of MRSA was performed by amplification of the mecA gene. Antimicrobial susceptibility was evaluated via the Kirby-Bauer disc diffusion susceptibility test protocol, using commonly applied antibiotics and the oxazolidinone analogues. Only (R)-5-((S)-1-dibenzylaminoethyl)-1,3-oxazolidin-2-one (7a) exhibited antibacterial activity at 6.6 μg. These results, allow us to infer that molecules such as 7a can be potentially used to treat infections caused by MRSA strains. PMID:24675696

  16. Antibacterial activity of essential oil of north west Algerian Eucalyptus camaldulensis against Escherichia coli and Staphylococcus aureus

    Institute of Scientific and Technical Information of China (English)

    Bachir Raho Ghalem; Benali Mohamed

    2014-01-01

    Objective: To evaluate the in vitro antimicrobial activities of the crude oil of Eucalyptuscamaldulensis Methods: The essential oils of E. camaldulensis harvested from the garden of the Health Center in Sidi Bel Abbes city (North West of Algeria), were screened for their antibacterial activities against two clinical bacteria [Escherichia coli (E. coli), Staphylococcus aureus (S. aureus)] by the agar disc diffusion method and broth dilution susceptibility assay.Results:(E. camaldulensis) leaves. 31 mm and 10-26 mm respectively for E. coli and S. aureus. Gram positive S. aureus was more resistant to tested essential oil than Gram negative E. coli. The diameter of zones of inhibition by the leaf extracts of E. camaldulensis was 10-Conclusions: The results suggested a potential antimicrobial activity of the essential oil of E.camaldulensis, which may find its application in future research for the food and pharmaceutical industry.

  17. Curcumin Reverse Methicillin Resistance in Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Su-Hyun Mun

    2014-11-01

    Full Text Available Curcumin, a natural polyphenolic flavonoid extracted from the rhizome of Curcuma longa L., was shown to possess superior potency to resensitize methicillin-resistant Staphylococcus aureus (MRSA to antibiotics. Previous studies have shown the synergistic activity of curcumin with β-lactam and quinolone antibiotics. Further, to understand the anti-MRSA mechanism of curcumin, we investigated the potentiated effect of curcumin by its interaction in diverse conditions. The mechanism of anti-MRSA action of curcumin was analyzed by the viability assay in the presence of detergents, ATPase inhibitors and peptidoglycan (PGN from S. aureus, and the PBP2a protein level was analyzed by western blotting. The morphological changes in the curcumin-treated MRSA strains were investigated by transmission electron microscopy (TEM. We analyzed increased susceptibility to MRSA isolates in the presence of curcumin. The optical densities at 600 nm (OD600 of the suspensions treated with the combinations of curcumin with triton X-100 and Tris were reduced to 63% and 59%, respectively, compared to curcumin without treatment. N,N'-dicyclohexylcarbodiimide (DCCD and sodium azide (NaN3 were reduced to 94% and 55%, respectively. When peptidoglycan (PGN from S. aureus was combined with curcumin, PGN (0–125 μg/mL gradually blocked the antibacterial activity of curcumin (125 μg/mL; however, at a concentration of 125 µg/mL PGN, it did not completely block curcumin. Curcumin has a significant effect on the protein level of PBP2a. The TEM images of MRSA showed damage of the cell wall, disruption of the cytoplasmic contents, broken cell membrane and cell lysis after the treatment of curcumin. These data indicate a remarkable antibacterial effect of curcumin, with membrane permeability enhancers and ATPase inhibitors, and curcumin did not directly bind to PGN on the cell wall. Further, the antimicrobial action of curcumin involved in the PBP2a-mediated resistance mechanism was

  18. Molecular characterization of a crustin-like antimicrobial peptide in the giant tiger shrimp, Penaeus monodon, and its expression profile in response to various immunostimulants and challenge with WSSV.

    Science.gov (United States)

    Antony, Swapna P; Singh, I S Bright; Sudheer, N S; Vrinda, S; Priyaja, P; Philip, Rosamma

    2011-01-01

    A crustin-like antimicrobial peptide from the haemocytes of giant tiger shrimp, Penaeus monodon was partially characterized at the molecular level and phylogenetic analysis was performed. The partial coding sequence of 299 bp and 91 deduced amino acid residues possessed conserved cysteine residues characteristic of the shrimp crustins. Phylogenetic tree and sequence comparison clearly confirmed divergence of this crustin-like AMP from other shrimp crustins. The differential expression of the crustin-like AMP in P. monodon in response to the administration of various immunostimulants viz., two marine yeasts (Candida haemulonii S27 and Candida sake S165) and two β-glucan isolates (extracted from C. haemulonii S27 and C. sake S165) were noted during the study. Responses to the application of two gram-positive probiotic bacteria (Bacillus MCCB101 and Micrococcus MCCB104) were also observed. The immune profile was recorded pre- and post-challenge white spot syndrome virus (WSSV) by semi-quantitative RT-PCR. Expressions of seven WSSV genes were also observed for studying the intensity of viral infection in the experimental animals. The crustin-like AMP was found to be constitutively expressed in the animal and a significant down-regulation could be noted post-challenge WSSV. Remarkable down-regulation of the gene was observed in the immunostimulant fed animals pre-challenge followed by a significant up-regulation post-challenge WSSV. Tissue-wise expression of crustin-like AMP on administration of C. haemulonii and Bacillus showed maximum transcripts in gill and intestine. The marine yeast, C. haemulonii and the probiotic bacteria, Bacillus were found to enhance the production of crustin-like AMP and confer significant protection to P. monodon against WSSV infection.

  19. Staphylococcus aureus bacteraemia in a tropical setting: patient outcome and impact of antibiotic resistance.

    Directory of Open Access Journals (Sweden)

    Emma K Nickerson

    Full Text Available BACKGROUND: Most information on invasive Staphylococcus aureus infections comes from temperate countries. There are considerable knowledge gaps in epidemiology, treatment, drug resistance and outcome of invasive S. aureus infection in the tropics. METHODS: A prospective, observational study of S. aureus bacteraemia was conducted in a 1000-bed regional hospital in northeast Thailand over 1 year. Detailed clinical data were collected and final outcomes determined at 12 weeks, and correlated with antimicrobial susceptibility profiles of infecting isolates. PRINCIPAL FINDINGS: Ninety-eight patients with S. aureus bacteraemia were recruited. The range of clinical manifestations was similar to that reported from temperate countries. The prevalence of endocarditis was 14%. The disease burden was highest at both extremes of age, whilst mortality increased with age. The all-cause mortality rate was 52%, with a mortality attributable to S. aureus of 44%. Methicillin-resistant S. aureus (MRSA was responsible for 28% of infections, all of which were healthcare-associated. Mortality rates for MRSA and methicillin-susceptible S. aureus (MSSA were 67% (18/27 and 46% (33/71, respectively (p = 0.11. MRSA isolates were multidrug resistant. Only vancomycin or fusidic acid would be suitable as empirical treatment options for suspected MRSA infection. CONCLUSIONS: S. aureus is a significant pathogen in northeast Thailand, with comparable clinical manifestations and a similar endocarditis prevalence but higher mortality than industrialised countries. S. aureus bacteraemia is frequently associated with exposure to healthcare settings with MRSA causing a considerable burden of disease. Further studies are required to define setting-specific strategies to reduce mortality from S. aureus bacteraemia, prevent MRSA transmission, and to define the burden of S. aureus disease and emergence of drug resistance throughout the developing world.

  20. Supercritical CO2 extraction of Schinus molle L with co-solvents: mathematical modeling and antimicrobial applications

    OpenAIRE

    Rodrigo Scopel; Roberto Góes Neto; Manuel Alves Falcão; Eduardo Cassel; Rubem Mário Figueiró Vargas

    2013-01-01

    This work investigates the antimicrobial activity of the Schinus molle L. leaves extracts obtained under supercritical conditions using carbon dioxide and co-solvents. Antimicrobial qualitative evaluation was carried out through the bioautography technique and the microorganisms studied were Staphylococcus aureus, Pseudomonas aeruginosas, Escherichia coli, Micrococcus luteus, and Salmonella choleraesuis. The supercritical fluid extraction was carried out in a pilot scale equipment using carbo...

  1. The effect of low-intensity pulsed sound waves delivered by the Exogen device on Staphylococcus aureus morphology and genetics

    OpenAIRE

    2004-01-01

    Objectives: We investigated the effect of low-intensity pulsed sound waves delivered by the Exogen device, which is recommended for the treatment of delayed union and nonunion in orthopedic surgery, on the colony number, antimicrobial susceptibility, bacterial morphology, and genetics of Staphylococcus aureus, which is a frequent pathogen in orthopedic infections. Methods: Thirty tubes containing 0.5 McFarland suspensions of S. aureus (ATCC 25923) were used. Fifteen tubes forming the test ...

  2. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... how antimicrobial resistance both emerges and proliferates among bacteria. Over time, the use of antimicrobial drugs will result in the development of resistant strains of bacteria, complicating clinician's efforts to select the appropriate antimicrobial ...

  3. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... Veterinary Home Animal & Veterinary Safety & Health Antimicrobial Resistance Animation of Antimicrobial Resistance Share Tweet Linkedin Pin it ... Veterinary Medicine is cited as the corporate author. Animation Animation of Antimicrobial Resistance (WMV - 19.2MB) 9: ...

  4. Animation of Antimicrobial Resistance

    Science.gov (United States)

    ... Veterinary Safety & Health Antimicrobial Resistance Animation of Antimicrobial Resistance Share Tweet Linkedin Pin it More sharing options ... produced a nine-minute animation explaining how antimicrobial resistance both emerges and proliferates among bacteria. Over time, ...

  5. Nosocomial bloodstream infection in patients caused by Staphylococcus aureus: drug susceptibility, outcome, and risk factors for hospital mortality

    Institute of Scientific and Technical Information of China (English)

    CHEN Rong; YAN Zhong-qiang; FENG Dan; LUO Yan-ping; WANG Lei-li; SHEN Ding-xia

    2012-01-01

    Background Previous studies have different viewpoints about the clinical impact of methicillin resistance on mortality of hospital-acquired bloodstream infection (BSI) patients with Staphylococcus aureus (S.aureus).The objective of this study was to investigate the mortality of hospital-acquired BSI with S.aureus in a military hospital and analyze the risk factors for the hospital mortality.Methods A retrospective cohort study was performed in patients admitted to the biggest military tertiary teaching hospital in China between January 2006 and May 2011.All included patients had clinically significant nosocomial BSI with S.aureus.Multivariate Logistic regression analysis was used to identify the risk factors for hospital mortality of patients with S.aureus BSI.Results One hundred and eighteen patients of more than one year old were identified as clinically and microbiologically confirmed nosocomial bacteraemia due to S.aureus,and 75 out of 118 patients were infected with methicillin-resistant S.aureus (MRSA).The overall mortality of nosocomial S.aureus BSI was 28.0%.Methicillin resistance in S.aureus bacteremia was associated with significant increase in the length of hospitalization and high proportion of inappropriate empirical antibiotic treatment.After Logistic regression analysis,the severity of clinical manifestations (APACHE Ⅱ score) (odds ratio (OR) 1.22,95% confidence interval (CI) 1.12-1.34) and inadequacy of empirical antimicrobial therapy (OR 0.25,95% CI 0.09-0.69) remained as risk factors for hospital mortality.Conclusions Nosocomial S.aureus BSI was associated with high in-hospital mortality.Methicillin resistance in S.aureus has no significant impact on the outcome of patients with staphylococcal bacteremia.Proper empirical antimicrobial therapy is very important to the prognosis.

  6. Antibacterial Activity of Cold Atmospheric Pressure Argon Plasma against 78 Genetically Different (mecA, luk-P, agr or Capsular Polysaccharide Type) Staphylococcus aureus Strains.

    Science.gov (United States)

    Matthes, Rutger; Lührman, Anne; Holtfreter, Silva; Kolata, Julia; Radke, Dörte; Hübner, Nils-Olaf; Assadian, Ojan; Kramer, Axel

    2016-01-01

    Previous studies on the antimicrobial activity of cold atmospheric pressure argon plasma showed varying effects against mecA+ or mecA-Staphylococcus aureus strains. This observation may have important clinical and epidemiological implications. Here, the antibacterial activity of argon plasma was investigated against 78 genetically different S. aureus strains, stratified by mecA, luk-P, agr1-4, or the cell wall capsule polysaccharide types 5 and 8. kINPen09® served as the plasma source for all experiments. On agar plates, mecA+luk-P-S. aureus strains showed a decreased susceptibility against plasma compared to other S. aureus strains. This study underlines the high complexity of microbial defence against antimicrobial treatment and confirms a previously reported strain-dependent susceptibility of S. aureus to plasma treatment.

  7. Global network analysis of drug tolerance, mode of action and virulence in methicillin-resistant S. aureus

    Directory of Open Access Journals (Sweden)

    Shirran Sally

    2011-05-01

    Full Text Available Abstract Background Staphylococcus aureus is a major human pathogen and strains resistant to existing treatments continue to emerge. Development of novel treatments is therefore important. Antimicrobial peptides represent a source of potential novel antibiotics to combat resistant bacteria such as Methicillin-Resistant Staphylococcus aureus (MRSA. A promising antimicrobial peptide is ranalexin, which has potent activity against Gram-positive bacteria, and particularly S. aureus. Understanding mode of action is a key component of drug discovery and network biology approaches enable a global, integrated view of microbial physiology, including mechanisms of antibiotic killing. We developed a systems-wide functional association network approach to integrate proteome and transcriptome profiles, enabling study of drug resistance and mode of action. Results The functional association network was constructed by Bayesian logistic regression, providing a framework for identification of antimicrobial peptide (ranalexin response modules from S. aureus MRSA-252 transcriptome and proteome profiling. These signatures of ranalexin treatment revealed multiple killing mechanisms, including cell wall activity. Cell wall effects were supported by gene disruption and osmotic fragility experiments. Furthermore, twenty-two novel virulence factors were inferred, while the VraRS two-component system and PhoU-mediated persister formation were implicated in MRSA tolerance to cationic antimicrobial peptides. Conclusions This work demonstrates a powerful integrative approach to study drug resistance and mode of action. Our findings are informative to the development of novel therapeutic strategies against Staphylococcus aureus and particularly MRSA.

  8. New epidemiology of Staphylococcus aureus infection in Asia.

    Science.gov (United States)

    Chen, C-J; Huang, Y-C

    2014-07-01

    Not only is Asia the most populous region in the world, but inappropriate therapy, including self-medication with over-the-counter antimicrobial agents, is a common response to infectious diseases. The high antibiotic selective pressure among the overcrowded inhabitants creates an environment that is suitable for the rapid development and efficient spread of numerous multidrug-resistant pathogens. Indeed, Asia is among the regions with the highest prevalence rates of healthcare-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) and community-associated methicillin-resistant S. aureus (CA-MRSA) in the world. Most hospitals in Asia are endemic for multidrug-resistant methicillin-resistant S. aureus (MRSA), with an estimated proportion from 28% (in Hong Kong and Indonesia) to >70% (in Korea) among all clinical S. aureus isolates in the early 2010s. Isolates with reduced susceptibility or a high level of resistance to glycopeptides have also been increasingly identified in the past few years. In contrast, the proportion of MRSA among community-associated S. aureus infections in Asian countries varies markedly, from 35%. Two pandemic HA-MRSA clones, namely multilocus sequence type (ST) 239 and ST5, are disseminated internationally in Asia, whereas the molecular epidemiology of CA-MRSA in Asia is characterized by clonal heterogeneity, similar to that in Europe. In this review, the epidemiology of S. aureus in both healthcare facilities and communities in Asia is addressed, with an emphasis on the prevalence, clonal structure and antibiotic resistant profiles of the MRSA strains. The novel MRSA strains from livestock animals have been considered to constitute a public health threat in western countries. The emerging livestock-associated MRSA strains in Asia are also included in this review.

  9. Eugenol Provokes ROS-Mediated Membrane Damage-Associated Antibacterial Activity Against Clinically Isolated Multidrug-Resistant Staphylococcus aureus Strains.

    Science.gov (United States)

    Das, Balaram; Mandal, Debasis; Dash, Sandeep Kumar; Chattopadhyay, Sourav; Tripathy, Satyajit; Dolai, Durga Pada; Dey, Sankar Kumar; Roy, Somenath

    2016-01-01

    Due to the indiscriminate use of antibiotics, resistance to antibiotics has increased remarkably in Staphylococcus aureus. Vancomycin is the final drug to treat the S. aureus infection, but nowadays, resistance to this antibiotic is also increasing. So, the investigation of antibiotic resistance pattern is important. As there is already resistance to vancomycin, there is an urgent need to develop a new kind of antimicrobial to treat S. aureus infection. Eugenol may be the new drug of choice. This study was conducted to evaluate the antibacterial activity of eugenol against vancomycin-resistant S. aureus isolated from clinical pus samples. Thirty six pus samples were included in the study. Samples were isolated, identified and antimicrobial susceptibility tests were performed as per routine laboratory protocol. The antimicrobial activity and mechanisms of killing of eugenol were studied. Out of 36 pus samples, only 20 isolates were confirmed as S. aureus strains and 6 isolates exhibited vancomycin resistance. Eugenol successfully destroyed the vancomycin-resistant strains via reactive oxygen species generation and membrane damage. The prevalence of vancomycin resistance is increased day by day in different countries, and necessary steps to prevent the spread and emergence of resistance should be taken. The findings of the study suggested that eugenol might be used to treat vancomycin-resistant S. aureus.

  10. Animation of Antimicrobial Resistance

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    Full Text Available ... More in Antimicrobial Resistance National Antimicrobial Resistance Monitoring ... Note: If you need help accessing information in different file formats, see Instructions for Downloading ...

  11. Animation of Antimicrobial Resistance

    Science.gov (United States)

    ... Animal & Veterinary Cosmetics Tobacco Products Animal & ... antimicrobial resistance both emerges and proliferates among bacteria. Over time, the use of antimicrobial drugs will result in the development ...

  12. Chemical composition of fennel essential oil and its impact on Staphylococcus aureus exotoxin production.

    Science.gov (United States)

    Qiu, Jiazhang; Li, Hongen; Su, Hongwei; Dong, Jing; Luo, Mingjing; Wang, Jianfeng; Leng, Bingfeng; Deng, Yanhong; Liu, Juxiong; Deng, Xuming

    2012-04-01

    In this study, fennel oil was isolated by hydrodistillation, and the chemical composition was determined by gas chromatography/mass spectral analysis. The antimicrobial activity of fennel oil against Staphylococcus aureus was evaluated by broth microdilution. A haemolysis assay, tumour necrosis factor (TNF) release assay, western blot, and real-time reverse transcription (RT)-PCR were applied to investigate the influence of fennel oil on the production of S. aureus virulence-related exoproteins. The data show that fennel oil, which contains a high level of trans-anethole, was active against S. aureus, with MICs ranging from 64 to 256 μg/ml. Furthermore, fennel oil, when used at subinhibitory concentrations, could dose-dependently decrease the expression of S. aureus exotoxins, including α-toxin, Staphylococcal enterotoxins (SEs) and toxic shock syndrome toxin 1 (TSST-1).

  13. Reversible antibiotic tolerance induced in Staphylococcus aureus by concurrent drug exposure

    DEFF Research Database (Denmark)

    Haaber, Jakob Krause; Friberg, Cathrine; McCreary, Mark;

    2015-01-01

    UNLABELLED: Resistance of Staphylococcus aureus to beta-lactam antibiotics has led to increasing use of the glycopeptide antibiotic vancomycin as a life-saving treatment for major S. aureus infections. Coinfection by an unrelated bacterial species may necessitate concurrent treatment with a second...... antibiotic that targets the coinfecting pathogen. While investigating factors that affect bacterial antibiotic sensitivity, we discovered that susceptibility of S. aureus to vancomycin is reduced by concurrent exposure to colistin, a cationic peptide antimicrobial employed to treat infections by Gram......-negative pathogens. We show that colistin-induced vancomycin tolerance persists only as long as the inducer is present and is accompanied by gene expression changes similar to those resulting from mutations that produce stably inherited reduction of vancomycin sensitivity (vancomycin-intermediate S. aureus [VISA...

  14. Analysis of skin and secretions of Dybowski's frogs (Rana dybowskii) exposed to Staphylococcus aureus or Escherichia coli identifies immune response proteins.

    Science.gov (United States)

    Xiao, Xiang-Hong; Miao, Hui-Min; Xu, Yi-Gang; Zhang, Jing-Yu; Chai, Long-Hui; Xu, Jia-Jia

    2014-04-01

    The aim of the present study was to investigate responses in Dybowski's frogs (Rana dybowskii) exposed to bacteria, using proteomic and transcriptomic approaches. Staphylococcus aureus and Escherichia coli were used as representative Gram-positive and Gram-negative bacteria, respectively, in an infectious challenge model. Frog skin and skin secretions were collected and protein expression in infected frogs compared to control frogs by two-dimensional gel electrophoresis, silver staining, and image analysis. Proteins that demonstrated differential expression were analysed by mass spectrometry and identified by searching protein databases. More than 180 protein spots demonstrated differential expression in E. coli- or S. aureus-challenged groups and, of these, more than 55 spots were up- or down-regulated at least sixfold, post-infection. Proteins with a potential function in the immune response were identified, such as stathmin 1a, annexin A1, superoxide dismutase A, C-type lectin, lysozyme, antimicrobial peptides, cofilin-1-B, mannose receptor, histone H4, prohormone convertase 1, carbonyl reductase 1 and some components of the Toll-like receptor (TLR) signalling pathway. These molecules are potential candidates for further investigation of immune mechanisms in R. dybowskii; in particular, TLR-mediated responses, which might be activated in frogs exposed to pathogenic bacteria as part of innate immune defence, but which might also impact on adaptive immunity to infection.

  15. Antimicrobial resistance

    DEFF Research Database (Denmark)

    Llor, Carl; Bjerrum, Lars

    2014-01-01

    is associated with an increased risk of adverse effects, more frequent re-attendance and increased medicalization of self-limiting conditions. Antibiotic overprescribing is a particular problem in primary care, where viruses cause most infections. About 90% of all antibiotic prescriptions are issued by general......-the-counter sale of antibiotics, the use of antimicrobial stewardship programmes, the active participation of clinicians in audits, the utilization of valid rapid point-of-care tests, the promotion of delayed antibiotic prescribing strategies, the enhancement of communication skills with patients with the aid...

  16. Comparative Evaluation of the Antimicrobial Activity of Different Antimicrobial Peptides against a Range of Pathogenic Bacteria

    DEFF Research Database (Denmark)

    Ebbensgaard, Anna Elisabeth; Mordhorst, Hanne; Overgaard, Michael Toft

    2015-01-01

    The rapid emergence of resistance to classical antibiotics has increased the interest in novel antimicrobial compounds. Antimicrobial peptides (AMPs) represent an attractive alternative to classical antibiotics and a number of different studies have reported antimicrobial activity data of various...... AMPs, but there is only limited comparative data available. The mode of action for many AMPs is largely unknown even though several models have suggested that the lipopolysaccharides (LPS) play a crucial role in the attraction and attachment of the AMP to the bacterial membrane in Gram......-negative bacteria. We compared the potency of Cap18, Cap11, Cap11-1-18m2, Cecropin P1, Cecropin B, Bac2A, Bac2A-NH2, Sub5-NH2, Indolicidin, Melittin, Myxinidin, Myxinidin-NH2, Pyrrhocoricin, Apidaecin and Metalnikowin I towards Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, Escherichia coli...

  17. Bacillus licheniformis isolated from Korean traditional food sources enhances the resistance of Caenorhabditis elegans to infection by Staphylococcus aureus.

    Science.gov (United States)

    Yun, Hyun Sun; Heo, Ju Hee; Son, Seok Jun; Park, Mi Ri; Oh, Sangnam; Song, Min-Ho; Kim, Jong Nam; Go, Gwang-Woong; Cho, Ho-Seong; Choi, Nag-Jin; Jo, Seung-Wha; Jeong, Do-Youn; Kim, Younghoon

    2014-08-01

    We investigated whether Bacillus spp., newly isolated from Korean traditional food resources, influence the resistance of hosts to foodborne pathogens, by using Caenorhabditis elegans as a surrogate host model. Initially, we selected 20 Bacillus spp. that possess antimicrobial activity against various foodborne pathogens, including Staphylococcus aureus. Among the selected strains, six strains of Bacillus spp. used in preconditioning significantly prolonged the survival of nematodes exposed to S. aureus. Based on 16S rRNA gene sequencing, all six strains were identified as B. licheniformis. Our findings suggest that preconditioning with B. licheniformis may modulate the host defense response against S. aureus.

  18. Importance of antimicrobial stewardship to the English National Health Service

    Directory of Open Access Journals (Sweden)

    Dixon J

    2014-05-01

    priorities include establishing novel approaches to antimicrobial management (eg, duration of therapy, combination regimens to protect against resistance and working with the pharmaceutical industry to promote the development of new antimicrobials. Keywords: antimicrobial resistance, antibiotics, National Health Service, methicillin-resistant Staphylococcus aureus, Clostridium difficile, prescribing

  19. Antimicrobial activity ofGymnema sylvestre (Asclepiadaceae)

    Institute of Scientific and Technical Information of China (English)

    Beverly C. David; G. Sudarsanam

    2013-01-01

    Objective:To evaluate antimicrobial activities of aqueous, methanol, chloroform and hexane extract of leaves plant ofGymnema sylvestre(G. sylvestre).Methods:The antimicrobial screening of the extracts ofG. sylvestre against most prevalent microbes likeStaphylococcus aureus(S. aureus),Bacillus cereus(B. cereus),Klebsiella pneumoniae(K. pneumoniae),Escherichia coli(E. coli),Candida albicans(C. albicans),Candida tropicalis(C. tropicalis),Candida krusei(C. krusei) andCandida kefyr(C. kefyr) by agar well diffusion method, minimum inhibitory concentration, minimum bactericidal concentration, minimum fungicidal concentration were carried out. Results:The aqueous and methanol leaf extract showed significant antibacterial and antifungal activities against the selected microorganisms when compared to the standard drugs respectively. Conclusions:The dried scale leaves ofG. sylvestre might represent a new antimicrobial source with stable, biologically active components that can establish a scientific base for the use in modern medicine.

  20. Development of a broad spectrum polymer-released antimicrobial coating for the prevention of resistant strain bacterial infections.

    Science.gov (United States)

    Sinclair, K D; Pham, T X; Farnsworth, R W; Williams, D L; Loc-Carrillo, C; Horne, L A; Ingebretsen, S H; Bloebaum, R D

    2012-10-01

    More than 400,000 primary hip and knee replacement surgeries are performed each year in the United States. From these procedures, approximately 0.5-3% will become infected and when considering revision surgeries, this rate has been found to increase significantly. Antibiotic-resistant bacterial infections are a growing problem in patient care. This in vitro research investigated the antimicrobial potential of the polymer released, broad spectrum, Cationic Steroidal Antimicrobial-13 (CSA-13) for challenges against 5 × 10(8) colony forming units (CFU) of methicillin-resistant Staphylococcus aureus (MRSA). It was hypothesized that a weight-to-weight (w/w) concentration of 18% CSA-13 in silicone would exhibit potent bactericidal potential when used as a controlled release device coating. When incorporated into a polymeric device coating, the 18% (w/w) broad-spectrum polymer released CSA-13 antimicrobial eliminated 5 × 10(8) CFU of MRSA within 8 h. In the future, these results will be utilized to develop a sheep model to assess CSA-13 for the prevention of perioperative device-related infections in vivo.

  1. Cicatrizing and antimicrobial properties of an ozonised oil from sunflower seeds.

    Science.gov (United States)

    Rodrigues, Kamila Leite; Cardoso, Claudia Catellani; Caputo, Lucelia Regina; Carvalho, Jose Carlos Tavares; Fiorini, Joao Evangelista; Schneedorf, Jose Mauricio

    2004-01-01

    The ozonised sunflower oil, Bioperoxoil, was tested for its antimicrobial activity against some pathological strains in vitro together with its healing potential against Staphylococcus aureus in vivo. Bioperoxoil was tested against S. aureus, Pseudomonas aeroginosa, Candida albicans, S. typhimurium and Escherichia coli suspensions using the agar diffusion method. Healing experiments were carried out with Wistar rats through topical application of 3.5 mg/ml of the ozonised oil up to the 7th day after inoculation with S. aureus. Bioperoxoil showed anti-inflammatory effects against all strains tested, with MIC values ranging from 2.0 to 3.5 mg/ml. Bioperoxoil also demonstrated protective effects on skin connective tissue and to enhance wound healing during the treatment, as compared to a neomycin-clostebol association used as a positive control. The overall results indicated a significant antimicrobial activity, anti-inflammatory and wound-healing properties for Bioperoxoil, as compared to other antimicrobial agents commercially available.

  2. Antimicrobial Activity of Xanthohumol and Its Selected Structural Analogues

    Directory of Open Access Journals (Sweden)

    Monika Stompor

    2016-05-01

    Full Text Available The objective of this study was to evaluate the antimicrobial activity of structural analogues of xanthohumol 1, a flavonoid compound found in hops (Humulus lupulus. The agar-diffusion method using filter paper disks was applied. Biological tests performed for selected strains of Gram-positive (Staphylococcus aureus and Gram-negative (Escherichia coli bacteria, fungi (Alternaria sp., and yeasts (Rhodotorula rubra, Candida albicans revealed that compounds with at least one hydroxyl group—all of them have it at the C-4 position—demonstrated good activity. Our research showed that the strain S. aureus was more sensitive to chalcones than to the isomers in which the heterocyclic ring C is closed (flavanones. The strain R. rubra was moderately sensitive to only one compound: 4-hydroxy-4’-methoxychalcone 8. Loss of the hydroxyl group in the B-ring of 4’-methoxychalcones or its replacement by a halogen atom (−Cl, −Br, nitro group (−NO2, ethoxy group (−OCH2CH3, or aliphatic substituent (−CH3, −CH2CH3 resulted in the loss of antimicrobial activity towards both R. rubra yeast and S. aureus bacteria. Xanthohumol 1, naringenin 5, and chalconaringenin 7 inhibited growth of S. aureus, whereas 4-hydroxy-4′-methoxychalcone 8 was active towards two strains: S. aureus and R. rubra.

  3. Antimicrobial Activity of Xanthohumol and Its Selected Structural Analogues.

    Science.gov (United States)

    Stompor, Monika; Żarowska, Barbara

    2016-05-11

    The objective of this study was to evaluate the antimicrobial activity of structural analogues of xanthohumol 1, a flavonoid compound found in hops (Humulus lupulus). The agar-diffusion method using filter paper disks was applied. Biological tests performed for selected strains of Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria, fungi (Alternaria sp.), and yeasts (Rhodotorula rubra, Candida albicans) revealed that compounds with at least one hydroxyl group-all of them have it at the C-4 position-demonstrated good activity. Our research showed that the strain S. aureus was more sensitive to chalcones than to the isomers in which the heterocyclic ring C is closed (flavanones). The strain R. rubra was moderately sensitive to only one compound: 4-hydroxy-4'-methoxychalcone 8. Loss of the hydroxyl group in the B-ring of 4'-methoxychalcones or its replacement by a halogen atom (-Cl, -Br), nitro group (-NO₂), ethoxy group (-OCH₂CH₃), or aliphatic substituent (-CH₃, -CH₂CH₃) resulted in the loss of antimicrobial activity towards both R. rubra yeast and S. aureus bacteria. Xanthohumol 1, naringenin 5, and chalconaringenin 7 inhibited growth of S. aureus, whereas 4-hydroxy-4'-methoxychalcone 8 was active towards two strains: S. aureus and R. rubra.

  4. Short communication: Outbreak of methicillin-resistant Staphylococcus aureus (MRSA)-associated mastitis in a closed dairy herd.

    Science.gov (United States)

    Guimarães, F F; Manzi, M P; Joaquim, S F; Richini-Pereira, V B; Langoni, H

    2017-01-01

    Cows are probably the main source of contamination of raw milk with Staphylococcus aureus. Mammary glands with subclinical mastitis can shed large numbers of Staph. aureus in milk. Because of the risk of this pathogen to human health as well as animal health, the aim of this paper was to describe an outbreak of mastitis caused by methicillin-resistant Staph. aureus (MRSA), oxacillin-susceptible mecA-positive Staph. aureus (OS-MRSA), and methicillin-susceptible Staph. aureus (MSSA) on a dairy farm. Milk samples were obtained from all quarters, showing an elevated somatic cell count by the California Mastitis Test. The isolates were identified by phenotypic and genotypic methods. Staphylococcus spp. were isolated from 53% (61/115) of the milk samples, with 60 isolates identified as Staph. aureus (98.4%) and 1 isolate identified as Staphylococcus epidermidis (1.6%). The presence of the mecA gene was verified in 48.3% of Staph. aureus isolates. Of the Staph. aureus isolates, 23.3% were MRSA and 25.0% were OS-MRSA. The total of mastitis cases infected with MRSA was 12.2%. The detection of this large percentage of mastitis cases caused by MRSA and OS-MRSA is of great concern for the animals' health, because β-lactams are still the most important antimicrobials used to treat mastitis. In addition, Staph. aureus isolates causing bovine mastitis represent a public health risk.

  5. In vitro antimicrobial activity of mangrove plant Sonneratia alba

    Institute of Scientific and Technical Information of China (English)

    Shahbudin Saad; Muhammad Taher; Deny Susanti; Haitham Qaralleh; Anis Fadhlina Izyani Bt Awang

    2012-01-01

    Objective:To investigate the antimicrobial property of mangrove plant Sonneratia alba (S. alba). Methods: The antimicrobial activity was evaluated using disc diffusion and microdilution methods against six microorganisms. Soxhlet apparatus was used for extraction with a series of solvents, n-hexane, ethyl acetate and methanol in sequence of increasing polarity. Results:Methanol extract appeared to be the most effective extract while n-hexane extract showed no activity. The antimicrobial activities were observed against the gram positive bacteria Staphylococcus aureus (S. aureus) and Bacillus cereus (B. cereus), the gram negative Escherichia coli (E. coli) and the yeast Cryptococcus neoformans. Pseudomonas aeruginosa and Candida albicans appeared to be not sensitive to the concentrations tested since no inhibition zone was observed. E. coli (17.5 mm) appeared to be the most sensitive strain followed by S. aureus (12.5 mm) and B. cereus (12.5 mm). Conclusions:From this study, it can be concluded that S. alba exhibits antimicrobial activities against certain microorganisms.

  6. Monoclonal Antibody Targeting Staphylococcus aureus Surface Protein A (SasA) Protect Against Staphylococcus aureus Sepsis and Peritonitis in Mice.

    Science.gov (United States)

    Yang, Yilong; Qian, Mengying; Yi, Shaoqiong; Liu, Shuling; Li, Bing; Yu, Rui; Guo, Qiang; Zhang, Xiaopeng; Yu, Changming; Li, Jianmin; Xu, Junjie; Chen, Wei

    2016-01-01

    Epidemic methicillin-resistant Staphylococcus aureus (MRSA) imposes an increasing impact on public health. Due to multi-antibiotics resistance in MRSA strains, there is an urgent need to develop novel therapeutics such as effective monoclonal antibodies (mAbs) against MRSA infections. Staphylococcus aureus surface protein A (SasA), a large surface-located protein (~240 kDa), is one of MSCRAMMs (microbial surface components recognizing adhesive matrix molecules) and a potential target for immunotherapeutic approaches against S. aureus infections. In the present study, we analyzed the sequence of SasA with bioinformatics tools and generated a protective monoclonal antibody (2H7) targeting the conserved domain of SasA. 2H7 was shown to recognize wild-type S. aureus and promote opsonophagocytic killing of S. aureus. In both sepsis and peritoneal infection models, prophylactic administration of 2H7 improved the survival of BALB/c mice challenged by S. aureus strain USA300 and ST239 (prevalent MRSA clones in North America and Asian countries, respectively) and enhanced bacterial clearance in kidneys. Additionally, 2H7 prophylaxis prevented the formation of intraperitoneal abscess in a murine model of peritoneal infection and therapeutic administration of 2H7 showed protective efficacy in a murine sepsis model. Our results presented here provide supporting evidences that an anti-SasA mAb might be a potential component in an antibody-based immunotherapeutic treatment of MRSA infections.

  7. Phevalin (aureusimine B) production by Staphylococcus aureus biofilm and impacts on human keratinocyte gene expression.

    Science.gov (United States)

    Secor, Patrick R; Jennings, Laura K; James, Garth A; Kirker, Kelly R; Pulcini, Elinor Delancey; McInnerney, Kate; Gerlach, Robin; Livinghouse, Tom; Hilmer, Jonathan K; Bothner, Brian; Fleckman, Philip; Olerud, John E; Stewart, Philip S

    2012-01-01

    Staphylococcus aureus biofilms are associated with chronic skin infections and are orders of magnitude more resistant to antimicrobials and host responses. S. aureus contains conserved nonribosomal peptide synthetases that produce the cyclic dipeptides tyrvalin and phevalin (aureusimine A and B, respectively). The biological function of these compounds has been speculated to be involved in virulence factor gene expression in S. aureus, protease inhibition in eukaryotic cells, and interspecies bacterial communication. However, the exact biological role of these compounds is unknown. Here, we report that S. aureus biofilms produce greater amounts of phevalin than their planktonic counterparts. Phevalin had no obvious impact on the extracellular metabolome of S. aureus as measured by high-performance liquid chromatography-mass spectrometry and nuclear magnetic resonance. When administered to human keratinocytes, phevalin had a modest effect on gene expression. However, conditioned medium from S. aureus spiked with phevalin amplified differences in keratinocyte gene expression compared to conditioned medium alone. Phevalin may be exploited as potential biomarker and/or therapeutic target for chronic, S. aureus biofilm-based infections.

  8. Antibacterial Action of Curcumin against Staphylococcus aureus: A Brief Review

    Science.gov (United States)

    Liew, Kitson; Ali, Syed A.; Khoo, Alan Soo-Beng; Peh, Suat-Cheng

    2016-01-01

    Curcumin, the major constituent of Curcuma longa L. (Zingiberaceae family) or turmeric, commonly used for cooking in Asian cuisine, is known to possess a broad range of pharmacological properties at relatively nontoxic doses. Curcumin is found to be effective against Staphylococcus aureus (S. aureus). As demonstrated by in vitro experiment, curcumin exerts even more potent effects when used in combination with various other antibacterial agents. Hence, curcumin which is a natural product derived from plant is believed to have profound medicinal benefits and could be potentially developed into a naturally derived antibiotic in the future. However, there are several noteworthy challenges in the development of curcumin as a medicine. S. aureus infections, particularly those caused by the multidrug-resistant strains, have emerged as a global health issue and urgent action is needed. This review focuses on the antibacterial activities of curcumin against both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA). We also attempt to highlight the potential challenges in the effort of developing curcumin into a therapeutic antibacterial agent. PMID:27956904

  9. Antibacterial Action of Curcumin against Staphylococcus aureus: A Brief Review

    Directory of Open Access Journals (Sweden)

    Sin-Yeang Teow

    2016-01-01

    Full Text Available Curcumin, the major constituent of Curcuma longa L. (Zingiberaceae family or turmeric, commonly used for cooking in Asian cuisine, is known to possess a broad range of pharmacological properties at relatively nontoxic doses. Curcumin is found to be effective against Staphylococcus aureus (S. aureus. As demonstrated by in vitro experiment, curcumin exerts even more potent effects when used in combination with various other antibacterial agents. Hence, curcumin which is a natural product derived from plant is believed to have profound medicinal benefits and could be potentially developed into a naturally derived antibiotic in the future. However, there are several noteworthy challenges in the development of curcumin as a medicine. S. aureus infections, particularly those caused by the multidrug-resistant strains, have emerged as a global health issue and urgent action is needed. This review focuses on the antibacterial activities of curcumin against both methicillin-sensitive S. aureus (MSSA and methicillin-resistant S. aureus (MRSA. We also attempt to highlight the potential challenges in the effort of developing curcumin into a therapeutic antibacterial agent.

  10. Synthesis and function of phospholipids in Staphylococcus aureus.

    Science.gov (United States)

    Kuhn, Sebastian; Slavetinsky, Christoph J; Peschel, Andreas

    2015-02-01

    Phospholipids are the major components of bacterial membranes, and changes in phospholipid composition affect important cellular processes such as metabolism, stress response, antimicrobial resistance, and virulence. The most prominent phospholipids in Staphylococcus aureus are phosphatidylglycerol, lysyl-phosphatidylglycerol, and cardiolipin, whose biosynthesis is mediated by a complex protein machinery. Phospholipid composition of the staphylococcal membrane has to be continuously adjusted to changing external conditions, which is achieved by a series of transcriptional and biochemical regulatory mechanisms. This mini-review outlines the current state of knowledge concerning synthesis, regulation, and function of the major staphylococcal phospholipids.

  11. Pyrazole Based Inhibitors against Enzymes of Staphylococcus aureus

    DEFF Research Database (Denmark)

    Jagadeesan, G.; Vijayakuma, Vinodhkumar; Palayam, Malathy

    2015-01-01

    Pyrazole derivatives display a wide variety of biological activities such as antimicrobial, anti-inflammatory and anti-tumor activities. Its biological prominence has intrigued chemists and biologists in recent years to synthesize new pyrazole derivatives as antiviral, antibacterial and anticancer...... agents. The current study focuses on molecular docking and dynamics studies of pyrazole derivatives against Nucleosidase and DNA gyrase B of Staphylococcus aureus. Molecular docking and dynamics studies reveal that some of these derivatives show better binding abilities than some of the current drugs...

  12. Antimicrobial activity of aqueous and methanolic extracts of pomegranate fruit skin

    OpenAIRE

    Ali Sadeghian; Ahmad Ghorbani; Ahmad Mohamadi-Nejad; Hassan Rakhshandeh

    2011-01-01

    Objective: Punica granatum, commonly known as pomegranate, has emerged as a medicinal plant with potential antimicrobial activity. The present study was planned to evaluate this activity against both Gram positive Staphylococcus aureus (S. aureus) and negative Pseudomonas aeruginosa (P. aeruginosa) bacteria as well as against pathogenic yeast, Candida albicans (C. albicans). Material and Methods: The aqueous and methanolic extracts of pomegranate fruit skin were prepared using a Soxhalet a...

  13. Antimicrobial activity of aqueous and methanolic extracts of pomegranate fruit skin

    OpenAIRE

    Ali Sadeghian; Ahmad Ghorbani; Ahmad Mohamadi-Nejad; Hassan Rakhshandeh

    2011-01-01

    Objective: Punica granatum, commonly known as pomegranate, has emerged as a medicinal plant with potential antimicrobial activity. The present study was planned to evaluate this activity against both Gram positive Staphylococcus aureus (S. aureus) and negative Pseudomonas aeruginosa (P. aeruginosa) bacteria as well as against pathogenic yeast, Candida albicans (C. albicans).Material and Methods: The aqueous and methanolic extracts of pomegranate fruit skin were prepared using a Soxhalet appar...

  14. Measurement of antimicrobial activity of isolated bacteria from the Caspian sea and molecular identification of strains with antimicrobial effect

    Directory of Open Access Journals (Sweden)

    Sajad Harounabadi

    2015-12-01

    Full Text Available Introduction: Easy access and wide use of antimicrobial compounds led to the emergence of resistance among microorganisms. Therefore, screening and identifying antimicrobial compound with high effect of microorganisms in different environments is necessary and vital . Using microorganisms for biological aims change them to an important tool to control pathogens. Streptomyces griseus is one of them. The aim of this study is isolation of marine bacteria with antimicrobial effect against gram positive and negative bacteria. Finally, molecular identification of strains with antimicrobial activity. Materials and methods: In this study, 162 strains were isolated from the Caspian Sea .The strains were cultured on special medium and finally antimicrobial activity on references strains as measured. Among them four strains with remarkable antimicrobial activity were identified and selected. The strains were subjected to 16S rDNA PCR sequencing. The strains were submitted to NCBI as new Streptomyces griseus strains. Results: Among 162 strains, 4 strains had the most antimicrobial activity. The result showed, the strains were the most effective on Bacillus subtilis and Staphylococcus aureus (Gram positive bacteria and the least effect were observed on Escherichia coli and Pseudomonas aeruginosa (Gram negative bacteria. After sequencing, the strains were classified to sterptomyces griseus genu. Discussion and conclusion: In this study, 4 strains with antimicrobial activity were identified. According to the strength of these bacteria for controlling pathogenic bacteria resistant to antibiotic, we can have more pure microorganisms in optimized and controlled conditions for using in pharmaceutical industries and also for the treatment of dangerous pathogenic bacteria.

  15. Antimicrobial resistance in India: A review.

    Science.gov (United States)

    Kumar, S Ganesh; Adithan, C; Harish, B N; Sujatha, S; Roy, Gautam; Malini, A

    2013-07-01

    Antimicrobial resistance is an important concern for the public health authorities at global level. However, in developing countries like India, recent hospital and some community based data showed increase in burden of antimicrobial resistance. Research related to antimicrobial use, determinants and development of antimicrobial resistance, regional variation and interventional strategies according to the existing health care situation in each country is a big challenge. This paper discusses the situational analysis of antimicrobial resistance with respect to its problem, determinants and challenges ahead with strategies required in future to reduce the burden in India. Recent data from Google search, Medline and other sources were collected which was reviewed and analyzed by the authors. Hospital based studies showed higher and varied spectrum of resistance in different regions while there are limited number of community based studies at country level. There exists lacunae in the structure and functioning of public health care delivery system with regard to quantification of the problem and various determining factors related to antimicrobial resistance. There is an urgent need to develop and strengthen antimicrobial policy, standard treatment guidelines, national plan for containment of AMR and research related to public health aspects of AMR at community and hospital level in India.

  16. Screening of some Malay medicated oils for antimicrobial activity

    Directory of Open Access Journals (Sweden)

    Khalid Khalisanni

    2010-01-01

    Full Text Available Oils from six Malay medicated oils, used traditionally in the treatment of infectious and septic diseases in humans, were tested for their antimicrobial property. The aim was to evaluate the antimicrobial properties of six Malay medicated oils against certain microbial isolates. Locally available Malay medicated oils were checked for their antimicrobial activities using six species of bacteria: E. coli, Salmonella spp., Klebsiella pneumoniae, Staphylococcus aureus, Streptococcus, Bacillus subtilis and 2 fungi with 1 yeast (Aspergillus niger, Penicillum spp. and Candida albicans. Clove oil showed the highest antibacterial activity followed, respectively, by 'bunga merah', cajaput, nutmeg, lemon grass and 'gamat' oil. Clove oil and lemon grass showed anticandidal activity. The Malay medicated oil studies did not show any antifungal activity. The study shows that Malay medicated oils, like antibiotics, have antimicrobial activities against some microorganisms.

  17. Study of antimicrobial property of some hypoglycemic drugs

    Directory of Open Access Journals (Sweden)

    Arun Kumar Dash

    2011-01-01

    Full Text Available In the present work, a comparative antimicrobial study of different hypoglycemic drugs (Metformin, Phenformin, and Rosiglitazone was carried out. The main objective was to ascertain the antimicrobial activity by using "non-antibiotics" as the test substances. The antimicrobial activity was carried out against different bacteria and fungi namely Bacillus liceniformis, Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa, Shigella flexneri, Bacillus subtilis, Staphylococcus aureus subspp., and Staphylococcus epidermidis by using disc diffusion method and agar dilution method. Ciprofloxacin was taken as the standard antibiotic. The entire procedure was carried out in an aseptic area under the laminar flow by inoculating the bacterial strain to the agar media in which the drug solution was added. Different concentrations (300 and 400 μg/ml of the standard antibiotic and selected drugs were subjected for minimum inhibitory concentration, and zone of inhibition tests and the antimicrobial activity of the selected drugs were determined.

  18. Antimicrobial activity of peppermint essential oil (Mentha piperita L.

    Directory of Open Access Journals (Sweden)

    Shapoval O.G.

    2011-12-01

    Full Text Available Рurposе. To study antimicrobial activity of fume of the essential oil of peppermint against gram-positive and gram-negative bacteria. Materials and methods: The screening study of antimicrobial activity of solutions of essential oil by disk-diffusion method and activity of essential oil fume of own preparation and pharmaceutical form of oil according to standard strains of Staphylococcus aureus, Pseudomonas aeruginosa, Esсherichia coli and 12 clinical strains of staphylococci (6 methicillin-resistant and 6 methicillin-sensitive has been carried out. Results: Essential oil of own preparation and pharmaceutical form showed equal antimicrobial activity against strains of staphylococci. Essential oil of own preparation has been determined to reveal higher activity against gram-negative strains. Conclusion: Received data have proved the presence of antimicrobial activity against all strains of microorganisms and mostly against staphy-lococci

  19. Colonization, pathogenicity, host susceptibility, and therapeutics for Staphylococcus aureus: what is the clinical relevance?

    Science.gov (United States)

    Tong, Steven Y C; Chen, Luke F; Fowler, Vance G

    2012-03-01

    Staphylococcus aureus is a human commensal that can also cause a broad spectrum of clinical disease. Factors associated with clinical disease are myriad and dynamic and include pathogen virulence, antimicrobial resistance, and host susceptibility. Additionally, infection control measures aimed at the environmental niches of S. aureus and therapeutic advances continue to impact upon the incidence and outcomes of staphylococcal infections. This review article focuses on the clinical relevance of advances in our understanding of staphylococcal colonization, virulence, host susceptibility, and therapeutics. Over the past decade key developments have arisen. First, rates of nosocomial methicillin-resistant S. aureus (MRSA) infections have significantly declined in many countries. Second, we have made great strides in our understanding of the molecular pathogenesis of S. aureus in general and community-associated MRSA in particular. Third, host risk factors for invasive staphylococcal infections, such as advancing age, increasing numbers of invasive medical interventions, and a growing proportion of patients with healthcare contact, remain dynamic. Finally, several new antimicrobial agents active against MRSA have become available for clinical use. Humans and S. aureus co-exist, and the dynamic interface between host, pathogen, and our attempts to influence these interactions will continue to rapidly change. Although progress has been made in the past decade, we are likely to face further surprises such as the recent waves of community-associated MRSA.

  20. Nasal Carriage of Staphylococcus aureus among Children in the Ashanti Region of Ghana

    Science.gov (United States)

    Hogan, Benedikt; Azuure, Clinton; Krumkamp, Ralf; Dekker, Denise; Gajdiss, Mike; Brunke, Melanie; Sarpong, Nimako; Owusu-Dabo, Ellis; May, Jürgen

    2017-01-01

    Background Nasal carriage with Staphylococcus aureus is a common risk factor for invasive infections, indicating the necessity to monitor prevalent strains, particularly in the vulnerable paediatric population. This surveillance study aims to identify carriage rates, subtypes, antimicrobial susceptibilities and virulence markers of nasal S. aureus isolates collected from children living in the Ashanti region of Ghana. Methods Nasal swabs were obtained from children < 15 years of age on admission to the Agogo Presbyterian Hospital between April 2014 and January 2015. S. aureus isolates were characterized by their antimicrobial susceptibility, the presence of genes encoding for Panton-Valentine leukocidin (PVL) and toxic shock syndrome toxin-1 (TSST-1) and further differentiated by spa-typing and multi-locus-sequence-typing. Results Out of 544 children 120 (22.1%) were colonized with S. aureus, with highest carriage rates during the rainy seasons (27.2%; p = 0.007), in females aged 6–8 years (43.7%) and males aged 8–10 years (35.2%). The 123 isolates belonged to 35 different spa-types and 19 sequence types (ST) with the three most prevalent spa-types being t355 (n = 25), t84 (n = 18), t939 (n = 13), corresponding to ST152, ST15 and ST45. Two (2%) isolates were methicillin-resistant S. aureus (MRSA), classified as t1096 (ST152) and t4454 (ST45), and 16 (13%) were resistant to three or more different antimicrobial classes. PVL and TSST-1 were detected in 71 (58%) and 17 (14%) isolates respectively. Conclusion S. aureus carriage among Ghanaian children seems to depend on age, sex and seasonality. While MRSA rates are low, the high prevalence of PVL is of serious concern as these strains might serve not only as a source for severe invasive infections but may also transfer genes, leading to highly virulent MRSA clones. PMID:28107412

  1. Evaluation of non-invasive biological samples to monitor Staphylococcus aureus colonization in great apes and lemurs.

    Directory of Open Access Journals (Sweden)

    Frieder Schaumburg

    Full Text Available INTRODUCTION: Reintroduction of endangered animals as part of conservational programs bears the risk of importing human pathogens from the sanctuary to the natural habitat. One bacterial pathogen that serves as a model organism to analyze this transmission is Staphylococcus aureus as it can colonize and infect both humans and animals. The aim of this study was to evaluate the utility of various biological samples to monitor S. aureus colonization in great apes and lemurs. METHODS: Mucosal swabs from wild lemurs (n=25, Kirindy, Madagascar, feces, oral and genital swabs from captive chimpanzees (n=58, Ngamba and Entebbe, Uganda and fruit wadges and feces from wild chimpanzees (n=21, Taï National Parc, Côte d'Ivoire were screened for S. aureus. Antimicrobial resistance and selected virulence factors were tested for each isolate. Sequence based genotyping (spa typing, multilocus sequence typing was applied to assess the population structure of S. aureus. RESULTS: Oro-pharyngeal carriage of S. aureus was high in lemurs (72%, n=18 and captive chimpanzees (69.2%, n=27 and 100%, n=6, respectively. Wild chimpanzees shed S. aureus through feces (43.8, n=7 and fruit wadges (54.5, n=12. Analysis of multiple sampling revealed that two samples are sufficient to detect those animals which shed S. aureus through feces or fruit wadges. Genotyping showed that captive animals are more frequently colonized with human-associated S. aureus lineages. CONCLUSION: Oro-pharyngeal swabs are useful to screen for S. aureus colonization in apes and lemurs before reintroduction. Duplicates of stool and fruit wadges reliably detect S. aureus shedding in wild chimpanzees. We propose to apply these sampling strategies in future reintroduction programs to screen for S. aureus colonization. They may also be useful to monitor S. aureus in wild populations.

  2. ANTIMICROBIAL ACTIVITY OF ETHANOLIC EXTRACTS OF SERRATULA CORONATA L. (ASTERACEAE) INTRODUCED IN ZHYTOMYR POLISSYA

    OpenAIRE

    I.V. Ivashchenko

    2016-01-01

    Antimicrobial properties of Serratula coronata L., introduced in Zhytomyr Polissya, were studied against test cultures of Escherichia coli (coliform bacillus) UCM B-906 (ATCC 25922), Staphylococcus aureus(golden staphylococcus) UCM B-904 (ATCC 25923), Pseudomonas aeruginosa (blue pus bacillus) UCM B-900 (ATCC9027), Candida albicans UCM Y-(ATCC 885-653). Serratula coronata L. 40 % ethanol extract showed potent antimicrobial effect against gram-positive bacteria Staphylococcus aureus. Compa...

  3. Antimicrobial activity ofTerminalia bellerica

    OpenAIRE

    Elizabeth, K. M.

    2005-01-01

    The antimicrobial activity of crude and methanol extract ofTerminalia bellerica dry fruit was tested by disc diffusion method, against 9 human microbial pathogens. Crude aqueous extract of dry fruit at 4 mg concentration showed zone of inhibition ranging from 15.5–28.0 mm.S. aureus was found to be highly susceptible forming highest zone of inhibition, suggesting thatT. bellerica was strongly inhibitory towards this organism. These pathogens were highly sensitive to the methanol extract formin...

  4. 3-Aryl-4-methyl-2-quinolones targeting multiresistant Staphylococcus aureus bacteria.

    Science.gov (United States)

    Doléans-Jordheim, Anne; Veron, Jean-Baptiste; Fendrich, Olivier; Bergeron, Emmanuelle; Montagut-Romans, Adrien; Wong, Yung-Sing; Furdui, Bianca; Freney, Jean; Dumontet, Charles; Boumendjel, Ahcène

    2013-04-01

    The NorA efflux pump lowers intracellular fluoroquinolone concentrations by expelling antibiotics through the membrane of Staphylococcus aureus. We identified 3-aryl-4-methyl-2-quinolin-2-ones as compounds able to restore the activity of the NorA substrate, ciprofloxacin, against resistant S. aureus strains, and acting as efflux pump inhibitors (EPI). In particular, 5-hydroxy-7-methoxy-4-methyl-3-phenylquinolin-2-one (6 c) presents both an EPI and an antimicrobial effect. Its efficacy and safety make it a potential candidate for further investigations.

  5. Improving time to optimal Staphylococcus aureus treatment using a penicillin-binding protein 2a assay.

    Science.gov (United States)

    Rao, Sonia N; Wang, Sheila K; Gonzalez Zamora, Jose; Hanson, Amy P; Polisetty, Radhika S; Singh, Kamaljit

    2016-12-01

    The penicillin-binding protein 2a (PBP2a) assay is a quick, accurate and inexpensive test for determining methicillin susceptibility in Staphylococcus aureus. A pre-post-study design was conducted using a PBP2a assay with and without the impact of an antimicrobial stewardship intervention to improve time to optimal therapy for methicillin-susceptible and methicillin-resistant S. aureus isolates. Our results demonstrate significantly improved time to optimal therapy and support the use of a PBP2a assay as part of an programme for all healthcare facilities, especially those with limited resources.

  6. Antimicrobial activity of Eucalyptus globulus oil, xylitol and papain: a pilot study

    Directory of Open Access Journals (Sweden)

    Valéria de Siqueira Mota

    2015-04-01

    Full Text Available OBJECTIVE To evaluate the in vitro antimicrobial activity of the Eucalyptus globulus essential oil, and of the xylitol and papain substances against the following microorganisms: Pseudomonas aeruginosa; Samonella sp.; Staphylococus aureus; Proteus vulgaris; Escherichia coli and Candida albicans. METHOD The in vitro antimicrobial evaluation was used by means of the agar diffusion test and evaluation of the inhibition zone diameter of the tested substances. Chlorhexidine 0.5% was used as control. RESULTS The Eucalyptus globulus oil showed higher inhibition than chlorhexidine when applied to Staphylococcus aureus, and equal inhibition when applied to the following microorganisms: Escherichia coli, Proteus vulgaris and Candida albicans. Papain 10% showed lower antimicrobial effect than chlorhexidine in relation to Candida albicans. Xylitol showed no inhibition of the tested microorganisms. CONCLUSION The Eucalyptus globulus oil has antimicrobial activity against different microorganisms and appears to be a viable alternative as germicidal agent hence, further investigation is recommended.

  7. Methicillin resistant S. aureus in human and bovine mastitis.

    Science.gov (United States)

    Holmes, Mark A; Zadoks, Ruth N

    2011-12-01

    Staphylococcus aureus is a ubiquitous organism that causes a variety of diseases including mastitis in cattle and humans. High-level resistance of S. aureus to β-lactams conferred by a mecA gene encoding a modified penicillin binding protein (PBP2a) was first observed in the early 1960's. These methicillin resistant S. aureus (MRSA) have been responsible for both hospital acquired infections (HA-MRSA) and, more recently, community acquired MRSA (CA-MRSA). A small number of human MRSA mastitis cases and outbreaks in maternity or neonatal units have been reported which are generally the result of CA-MRSA. The establishment of the sequence type 398 (ST398) in farm animals, primarily pigs, in the early 2000's has provided a reservoir of infection for humans and dairy cattle, particularly in continental Europe, described as livestock-associated MRSA (LA-MRSA). Prior to the emergence of ST398 there were sporadic reports of MRSA in bovine milk and cases of mastitis, often caused by strains from human associated lineages. Subsequently, there have been several reports describing bovine udder infections caused by ST-398 MRSA. Recently, another group of LA-MRSA strains was discovered in humans and dairy cattle in Europe. This group carries a divergent mecA gene and includes a number of S. aureus lineages (CC130, ST425, and CC1943) that were hitherto thought to be bovine-specific but are now also found as carriage or clinical isolates in humans. The emergence of MRSA in dairy cattle may be associated with contact with other host species, as in the case of ST398, or with the exchange of genetic material between S. aureus and coagulase negative Staphylococcus species, which are the most common species associated with bovine intramammary infections and commonly carry antimicrobial resistance determinants.

  8. Linezolid resistant Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Pavani Gandham

    2014-08-01

    Full Text Available Linezolid is the only antibiotic available as an oral formulation for resistant staphylococcal infections. It is effective in skin and soft tissue infections, nosocomial pneumonias including VAP, infective endocarditis and MRSA meningitis. It is also effective in the eradication of both nasal and throat colonization of MRSA. Its high bioavailability and post antibiotic effect, ease of switching to oral therapy during its use and the fact that it can be used in patients of all ages, also in patients with liver disease and poor kidney function and its increased effectiveness over glycopeptides makes this drug a precious drug in the treatment of resistant staphylococcal infections. Linezolid resistance in staphylococcus is defined as a linezolid MIC of and #8805;8 mg/L. Reported Linezolid resistance in India and elsewhere is 2-20%. There is clonal dissemination of Linezolid Resistant Staphylococcus aureus (LRSA within or across health care settings which demands continuous surveillance to determine the emergent risk of resistance strains and to establish guidelines for appropriate use. Clinical laboratories should confirm any LRSA preferably by a second method, prior to using linezolid for serious infections. Effective surveillance, more judicious use of this antibiotic, avoiding linezolid usage for empiric therapy in hospital acquired staphylococcus infections, optimization of the pharmacological parameters of the antibiotics in specific clinical situation, decreasing bacterial load by timely surgical debridement or drainage of collections, use of combination therapies would prevent the emergence of resistance to linezolid in staphylococcus aureus. [Int J Res Med Sci 2014; 2(4.000: 1253-1256

  9. Antimicrobial activity of Syagrus coronata (Martius Beccari

    Directory of Open Access Journals (Sweden)

    Alice Ferreira da Silva Hughes

    2013-04-01

    Full Text Available This work aimed to evaluate the antimicrobial activity of aqueous and methanol extracts of leaves, inflorescences, nut-shell, liquid and solid endosperm nuts of Syagrus coronata against pathogenic bacteria and yeast. Screening was initially performed using the agar dilution method. The extracts regarded as bioactive underwent liquid-liquid partition for determination of their minimum inhibitory concentration and minimum bactericide concentration (MIC and MBC and those of their respective fractions against the microorganisms inhibited in preliminary tests. Antimicrobial activity was observed only in inflorescences. The corresponding aqueous extract was effective against B. cereus and the three strains of S. aureus, and the corresponding MIC and MCB values were lower than those of dichloromethane, ethyl acetate and butanol fractions of the same extract. The methanol extract was effective against B. cereus, and the corresponding MIC and MBC values were higher than those of ethyl acetate and butanol fractions of the same extract.

  10. Spa Typing of Staphylococcus aureus Strains Isolated From Clinical Specimens of Patients With Nosocomial Infections in Tehran, Iran

    Science.gov (United States)

    Goudarzi, Mehdi; Fazeli, Maryam; Goudarzi, Hossein; Azad, Mehdi; Seyedjavadi, Sima Sadat

    2016-01-01

    Background The incidence of nosocomial Staphylococcus aureus infection is increasing annually and becoming a true global challenge. The pattern of Staphylococcus aureus protein A (spa) types in different geographic regions is diverse. Objectives This study determined the prevalence of methicillin-resistant S. aureus and different spa types in S. aureus clinical isolates. Materials and Methods During a six-month period, 90 S. aureus isolates were recovered from 320 clinical specimens. The in vitro susceptibility of various S. aureus isolates to 16 antibiotic discs was assessed using the Kirby-Bauer disk diffusion method. Molecular typing was carried out with S. aureus protein A typing via polymerase chain reaction. Results The frequency of methicillin-resistant S. aureus in our study was 88.9%. Twenty-three (25.5%) isolates were positive for panton-valentine leukocidin encoding genes. S. aureus presented a high resistance rate to ampicillin (100%) and penicillin (100%). No resistance was observed to vancomycin, teicoplanin, or linezolid. The rates of resistance to the majority of antibiotics tested varied between 23.3% and 82.2%. The rate of multidrug resistance among these clinical isolates was 93.3%. The 90 S. aureus isolates were classified into five S. aureus protein A types: t037 (33.3%), t030 (22.2%), t790 (16.7%), t969 (11.1%), and t044 (7.7%). Eight (8.9%) isolates were not typable using the S. aureus protein A typing method. Conclusions We report a high methicillin-resistant S. aureus rate in our hospital. Additionally, t030 and t037 were the predominant spa-types among hospital-associated S. aureus. Our findings emphasize the need for continuous surveillance to prevent the dissemination of multidrug resistance among different S. aureus protein A types in Iran. PMID:27679706

  11. Líquen aureus "algesiogênico" "Algesiogenic" lichen aureus

    Directory of Open Access Journals (Sweden)

    Roberto Rheingantz da Cunha Filho

    2006-03-01

    Full Text Available Descreve-se caso de líquen aureus em paciente do sexo feminino, com 23 anos de idade que apresentava há dois anos lesão dolorosa, purpúrica, acastanhada tendendo por semelhante a cor de ferrugem e de aspecto liquenóide no antebraço. O exame anatomopatológico revelou denso infiltrado linfo-histiocitário na derme superior papilar, com extravasamento de hemácias. O líquen aureus é relativamente raro, sendo ainda mais raro o sintoma de dor.A case is described of lichen aureus in a 23 year old female with a 2-year history of painful, purpuric, rust-coloured to tan, lichenous lesion on forearm. A biopsy specimen demonstrated a dense lymphohistiocytic infiltrate in the upper dermis, with extravasation of red cells. The "algesiogenic" lichen aureus is a very rare dermatosis.

  12. ANTIMICROBIAL ACTIVITY OF THE FRUIT-SEEDS MADHUCA LONGIFOLIA (KOENIG

    Directory of Open Access Journals (Sweden)

    Chirantan S Chakma

    2011-09-01

    Full Text Available The investigation was carried out to study the antibacterial activity of the Madhuca longifolia(Koenig in gram positive and gram negative organism.. Antimicrobial activity of the acetone and aqueous extracts of M.longifolia were determined against various pathogenic bacteria. The extracts were tested against various bacteria like Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginos, .E.coli by disk diffusion method. Minimum Inhibitory Concentration (MIC values of both extracts were determined. It is concluded that acetone extract exhibited significant antimicrobial activity. The study lends scientific support for it’s use in folk medicine.

  13. Antimicrobial polyurethane thermosets based on undecylenic acid: synthesis and evaluation.

    Science.gov (United States)

    Lluch, Cristina; Esteve-Zarzoso, Braulio; Bordons, Albert; Lligadas, Gerard; Ronda, Juan C; Galià, Marina; Cádiz, Virginia

    2014-08-01

    In the present study, plant oil-derived surface-modifiable polyurethane thermosets are presented. Polyol synthesis is carried out taking advantage of thiol-yne photopolymerization of undecylenic acid derivatives containing methyl ester or hydroxyl moieties. The prepared methyl ester-containing polyurethanes allow surface modification treatment to enhance their hydrophilicity and impart antimicrobial activity through the following two steps: i) grafting poly(propylene glycol) monoamine (Jeffamine M-600) via aminolysis and ii) Jeffamine M-600 layer complexation with iodine. The antimicrobial activity of the iodine-containing polyurethanes is demonstrated by its capacity to inhibit the growth of Staphylococcus aureus, and Candida albicans in agar media.

  14. Rifampicin fails to eradicate mature biofilm formed by methicillin-resistant Staphylococcus aureus

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    Keli Cristine Reiter

    2012-08-01

    Full Text Available INTRODUCTION: Antimicrobial activity on biofilms depends on their molecular size, positive charges, permeability coefficient, and bactericidal activity. Vancomycin is the primary choice for methicillin-resistant Staphylococcus aureus (MRSA infection treatment; rifampicin has interesting antibiofilm properties, but its effectivity remains poorly defined. METHODS: Rifampicin activity alone and in combination with vancomycin against biofilm-forming MRSA was investigated, using a twofold serial broth microtiter method, biofilm challenge, and bacterial count recovery. RESULTS: Minimal inhibitory concentration (MIC and minimal bactericidal concentration for vancomycin and rifampicin ranged from 0.5 to 1mg/l and 0.008 to 4mg/l, and from 1 to 4mg/l and 0.06 to 32mg/l, respectively. Mature biofilms were submitted to rifampicin and vancomycin exposure, and minimum biofilm eradication concentration ranged from 64 to 32,000 folds and from 32 to 512 folds higher than those for planktonic cells, respectively. Vancomycin (15mg/l in combination with rifampicin at 6 dilutions higher each isolate MIC did not reach in vitro biofilm eradication but showed biofilm inhibitory capacity (1.43 and 0.56log10 CFU/ml reduction for weak and strong biofilm producers, respectively; p<0.05. CONCLUSIONS: In our setting, rifampicin alone failed to effectively kill biofilm-forming MRSA, demonstrating stronger inability to eradicate mature biofilm compared with vancomycin.

  15. A field guide to pandemic, epidemic and sporadic clones of methicillin-resistant Staphylococcus aureus.

    Directory of Open Access Journals (Sweden)

    Stefan Monecke

    Full Text Available In recent years, methicillin-resistant Staphylococcus aureus (MRSA have become a truly global challenge. In addition to the long-known healthcare-associated clones, novel strains have also emerged outside of the hospital settings, in the community as well as in livestock. The emergence and spread of virulent clones expressing Panton-Valentine leukocidin (PVL is an additional cause for concern. In order to provide an overview of pandemic, epidemic and sporadic strains, more than 3,000 clinical and veterinary isolates of MRSA mainly from Germany, the United Kingdom, Ireland, France, Malta, Abu Dhabi, Hong Kong, Australia, Trinidad & Tobago as well as some reference strains from the United States have been genotyped by DNA microarray analysis. This technique allowed the assignment of the MRSA isolates to 34 distinct lineages which can be clearly defined based on non-mobile genes. The results were in accordance with data from multilocus sequence typing. More than 100 different strains were distinguished based on affiliation to these lineages, SCCmec type and the presence or absence of PVL. These strains are described here mainly with regard to clinically relevant antimicrobial resistance- and virulence-associated markers, but also in relation to epidemiology and geographic distribution. The findings of the study show a high level of biodiversity among MRSA, especially among strains harbouring SCCmec IV and V elements. The data also indicate a high rate of genetic recombination in MRSA involving SCC elements, bacteriophages or other mobile genetic elements and large-scale chromosomal replacements.

  16. A field guide to pandemic, epidemic and sporadic clones of methicillin-resistant Staphylococcus aureus.

    LENUS (Irish Health Repository)

    Monecke, Stefan

    2011-04-01

    In recent years, methicillin-resistant Staphylococcus aureus (MRSA) have become a truly global challenge. In addition to the long-known healthcare-associated clones, novel strains have also emerged outside of the hospital settings, in the community as well as in livestock. The emergence and spread of virulent clones expressing Panton-Valentine leukocidin (PVL) is an additional cause for concern. In order to provide an overview of pandemic, epidemic and sporadic strains, more than 3,000 clinical and veterinary isolates of MRSA mainly from Germany, the United Kingdom, Ireland, France, Malta, Abu Dhabi, Hong Kong, Australia, Trinidad & Tobago as well as some reference strains from the United States have been genotyped by DNA microarray analysis. This technique allowed the assignment of the MRSA isolates to 34 distinct lineages which can be clearly defined based on non-mobile genes. The results were in accordance with data from multilocus sequence typing. More than 100 different strains were distinguished based on affiliation to these lineages, SCCmec type and the presence or absence of PVL. These strains are described here mainly with regard to clinically relevant antimicrobial resistance- and virulence-associated markers, but also in relation to epidemiology and geographic distribution. The findings of the study show a high level of biodiversity among MRSA, especially among strains harbouring SCCmec IV and V elements. The data also indicate a high rate of genetic recombination in MRSA involving SCC elements, bacteriophages or other mobile genetic elements and large-scale chromosomal replacements.

  17. Evaluation of antimicrobial activity of selected plant extracts by rapid XTT colorimetry and bacterial enumeration.

    Science.gov (United States)

    Al-Bakri, Amal G; Afifi, Fatma U

    2007-01-01

    The aim of this study was to screen and evaluate the antimicrobial activity of indigenous Jordanian plant extracts, dissolved in dimethylsulfoxide, using the rapid XTT assay and viable count methods. XTT rapid assay was used for the initial screening of antimicrobial activity for the plant extracts. Antimicrobial activity of potentially active plant extracts was further assessed using the "viable plate count" method. Four degrees of antimicrobial activity (high, moderate, weak and inactive) against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, respectively, were recorded. The plant extracts of Hypericum triquetrifolium, Ballota undulata, Ruta chalepensis, Ononis natrix, Paronychia argentea and Marrubium vulgare had shown promising antimicrobial activity. This study showed that while both XTT and viable count methods are comparable when estimating the overall antimicrobial activity of experimental substances, there is no strong linear correlation between the two methods.

  18. Antimicrobial activity of tea as affected by the degree of fermentation and manufacturing season.

    Science.gov (United States)

    Chou, C C; Lin, L L; Chung, K T

    1999-05-01

    Bacillus subtilis, Escherichia coli, Proteus vulgaris, Pseudomonas fluorescens, Salmonella sp. and Staphylococcus aureus were used to test the antimicrobial activity of tea flush extract and extracts of various tea products. Among the six test organisms, P. fluorescens was the most sensitive to the extracts, while B. subtilis was the least sensitive. In general, antimicrobial activity decreased when the extents of tea fermentation increased. The antimicrobial activities of tea flush extract and extracts of tea products with different extents of fermentation varied with test organisms. Tea flush and Green tea, the unfermented tea, exerted the strongest antimicrobial activity followed by the partially fermented tea products such as Longjing, Tieh-Kuan-Ying, Paochung, and Oolong teas. On the other hand, Black tea, the completely fermented tea, showed the least antimicrobial activity. It was also noted that extracts of Oolong tea prepared in summer exhibited the strongest antimicrobial activity, followed by those prepared in spring, winter and fall.

  19. The Cell Wall Polymer Lipoteichoic Acid Becomes Nonessential in Staphylococcus aureus Cells Lacking the ClpX Chaperone

    DEFF Research Database (Denmark)

    Baek, Kristoffer T.; Bowman, Lisa; Millership, Charlotte;

    2016-01-01

    Lipoteichoic acid (LTA) is an important cell wall component of Gram-positive bacteria and a promising target for the development of vaccines and antimicrobial compounds against Staphylococcus aureus. Here we demonstrate that mutations in the conditionally essential ltaS (LTA synthase) gene arise...

  20. The Cell Wall Polymer Lipoteichoic Acid Becomes Nonessential in Staphylococcus aureus Cells Lacking the ClpX Chaperone

    DEFF Research Database (Denmark)

    Baek, Kristoffer T.; Bowman, Lisa; Millership, Charlotte;

    2016-01-01

    Lipoteichoic acid (LTA) is an important cell wall component of Gram-positive bacteria and a promising target for the development of vaccines and antimicrobial compounds against Staphylococcus aureus. Here we demonstrate that mutations in the conditionally essential ltaS (LTA synthase) gene arise ...

  1. Antimicrobial activity of histidine-rich peptides is dependent on acidic conditions.

    OpenAIRE

    Kacprzyk, Lukasz; Rydengård, Victoria; Mörgelin, Matthias; Davoudi, Mina; Pasupuleti, Mukesh; Malmsten, Martin; Schmidtchen, Artur

    2007-01-01

    Synthetic peptides composed of multiples of the consensus heparin-binding Cardin and Weintraub sequences AKKARA and ARKKAAKA are antimicrobial. Replacement of lysine and arginine by histidine in these peptides completely abrogates their antimicrobial and heparin-binding activities at neutral pH. However, the antibacterial activity against Gram-negative (Escherichia coli, Pseudomonas aeruginosa) and Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) as well as the fungus Cand...

  2. Photothermal killing of Staphylococcus aureus using antibody-targeted gold nanoparticles

    Directory of Open Access Journals (Sweden)

    Millenbaugh NJ

    2015-03-01

    Full Text Available Nancy J Millenbaugh,1 Jonathan B Baskin,1 Mauris N DeSilva,1 W Rowe Elliott,1 Randolph D Glickman2 1Maxillofacial Injury and Disease Department, Naval Medical Research Unit San Antonio, Joint Base San Antonio-Fort Sam Houston, TX, USA; 2Department of Ophthalmology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, USAPurpose: The continued emergence of multidrug resistant bacterial infections and the decline in discovery of new antibiotics are major challenges for health care throughout the world. This situation has heightened the need for novel antimicrobial therapies as alternatives to traditional antibiotics. The combination of metallic nanoparticles and laser exposure has been proposed as a strategy to induce physical damage to bacteria, regardless of antibiotic sensitivity. The purpose of this study was to test the antibacterial effect of antibody-targeted gold nanoparticles combined with pulsed laser irradiation.Methods: Gold nanoparticles conjugated to antibodies specific to Staphylococcus aureus peptidoglycan were incubated with suspensions of methicillin-resistant and methicillin-sensitive S. aureus (MRSA and MSSA. Bacterial suspensions were then exposed to 8 ns pulsed laser irradiation at a wavelength of 532 nm and fluences ranging from 1 to 5 J/cm2. Viability of the bacteria following laser exposure was determined using colony forming unit assays. Scanning electron microscopy was used to confirm the binding of nanoparticles to bacteria and the presence of cellular damage.Results: The laser-activated nanoparticle treatment reduced the surviving population to 31% of control in the MSSA population, while the survival in the MRSA population was reduced to 58% of control. Significant decreases in bacterial viability occurred when the laser fluence exceeded 1 J/cm2, and this effect was linear from 0 to 5 J/cm2 (r2=0.97. Significantly less bactericidal effect was observed for nonfunctionalized nanoparticles or

  3. In vitro evaluation of antimicrobial and antioxidant activity of Dragon ’s blood tree (Dracaena cinnabari Balf.f.) of Socotra Island (Yemen)

    OpenAIRE

    Abu-Taleb Ahmed Yehia; Fahad Ahmed Mohsen Alzowahi; Tukaram Angadrao Kadam; Rafik Usman Shaikh

    2013-01-01

    Objective: To evaluate the performance of preliminary phytochemical, antioxidant and antimicrobial activities of Dracaena cinnabari Balf.f. (Agavaceae) (D. cinnabari) resin, collected from Socotra Island (Yemen). Methods: The powdered stem resin is extracted with different solvents by using Soxhlet apparatus and evaluated for antioxidant and antimicrobial activity against three Gram positive bacteria (Bacillus cereus NCIM 2106, Staphylococcus aureus NCIM 2127, and Micrococcus l...

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

    Science.gov (United States)

    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.

  5. Antimicrobial compounds from Coleonema album (Rutaceae).

    Science.gov (United States)

    Esterhuizen, Lindy L; Meyer, Riaan; Dubery, Ian A

    2006-01-01

    Coleonema album, a member of the South African fynbos biome, was evaluated for its antimicrobial activity associated with its secondary metabolites. Ethanol- and acetone-based extracts obtained from plants from two different geographical areas were analyzed. A bioassay-guided fractionation methodology was followed for rapid and effective screening for the presence of bioactive compounds. The TLC-bioautographic method, used to screen the plant extracts for antimicrobial activity and localization of the active compounds, indicated the presence of a number of inhibitory compounds with activity against the microorganisms (E. coli, B. subtilis, E. faecalis, P. aeruginosa, S. aureus, M. smegmatis, M. tuberculosis, C. albicans, C. cucumerinum) tested. Evaluation of the inhibitory strength of each extract by the serial microdilution assay indicated that the C. album extracts inhibited effectively all the microorganisms, with the minimum inhibitory concentrations in the low mg ml(-1) range. Identification and structural information of the bioactive components were obtained by a combination of preparative TLC and LC-MS. It revealed the presence of coumarin aglycones which were responsible for the observed antimicrobial activities. The results of this study indicate that C. album possesses strong antimicrobial activity against a wide range of microorganisms that warrants further investigation into the use of the extracts or their active constituents as a potential source for novel drugs.

  6. Antimicrobial resistance and related issues: An overview of Bangladesh situation

    Directory of Open Access Journals (Sweden)

    Md. Sayedur Rahman

    2014-06-01

    Full Text Available The present study was designed to understand Bangladesh situation about antimicrobial resistance. Half of the Escherichia coli, Staphylococcus aureus, Pseudomonas and Klebsiella showed resistance against older and common antimicrobials. Most (50% common reasons to prescribe antimicrobial are fever, respiratory and urinary tract infection. About 70% prescriber mentioned diagnostic uncertainty and emergence of resistance as causes for increase in antimicrobial prescribing. 51.9% of prescribers opined that physicians prescribe antimicrobial more than the actual need. About two-third of 5th year medical students answered correctly on different issues related to antimicrobials and resistance. Antimicrobial and resistance received little emphasis in Pharmacology and Microbiology written questions at both undergraduate (0.7 to 16.1% and postgraduate (0.9 to 18.4% level. Print (0.02% to 2.0% and electronic media (0.0 to 0.6% attaches small importance on the issues. Nothing related to ‘antimicrobials’ and ‘measure to contain resistance’ were mentioned in related policy documents.

  7. Hydrocarbon-stapled lipopeptides exhibit selective antimicrobial activity.

    Science.gov (United States)

    Jenner, Zachary B; Crittenden, Christopher M; Gonzalez, Martín; Brodbelt, Jennifer S; Bruns, Kerry A

    2017-01-10

    Antimicrobial peptides (AMPs) occur widely in nature and have been studied for their therapeutic potential. AMPs are of interest due to the large number of possible chemical structural combinations using natural and unnatural amino acids, with varying effects on their biological activities. Using physicochemical properties from known naturally occurring amphipathic cationic AMPs, several hydrocarbon-stapled lipopeptides (HSLPs) were designed, synthesized, and tested for antimicrobial properties. Peptides were chemically modified by N-terminal acylation, C-terminal amidation, and some were hydrocarbon stapled by intramolecular olefin metathesis. The effects of peptide length, amphipathic character, and stapling on antimicrobial activity were tested against Escherichia coli, three species of Gram-positive bacteria (Staphylococcus aureus, Bacillus megaterium, and Enterococcus faecalis), and two strains of Candida albicans. Peptides were shown to disrupt liposomes of different phospholipid composition, as measured by leakage of a fluorescent compound from vesicles. Peptides with (S)-2-(4'-pentenyl)-alanine substituted for L-alanine in a reference peptide showed a marked increase in antimicrobial activity, hemolysis, and membrane disruption. Stapled peptides exhibited slightly higher antimicrobial potency; those with greatest hydrophobic character showed the greatest hemolysis and liposome leakage, but lower antimicrobial activity. The results support a model of HSLPs as membrane-disruptive AMPs with potent antimicrobial activity and relatively low hemolytic potential at biologically active peptide concentrations. This article is protected by copyright. All rights reserved.

  8. Antimicrobial Properties of α-MSH and Related Synthetic Melanocortins

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    A. Catania

    2006-01-01

    Full Text Available The natural antimicrobial peptides are ancient host defense effector molecules, present in organisms across the evolutionary spectrum. Several properties of α-melanocyte stimulating hormone (α-MSH suggested that it could be a natural antimicrobial peptide. α-MSH is a primordial peptide that appeared during the Paleozoic era, long before adaptive immunity developed and, like natural antimicrobial molecules, is produced by barrier epithelia, immunocytes, and within the central nervous system. α-MSH was discovered to have antimicrobial activity against two representative pathogens, Staphylococcus aureus and Candida albicans. The candidacidal influences of α-MSH appeared to be mediated by increases in cell cyclic adenosine monophosphate (cAMP. The cAMP-inducing capacity of α-MSH likely interferes with the yeast's own regulatory mechanisms of this essential signaling pathway. It is remarkable that this mechanism of action in yeast mimics the influences of α-MSH in mammalian cells in which the peptide binds to G-protein-linked melanocortin receptors, activates adenylyl cyclase, and increases cAMP. When considering that most of the natural antimicrobial peptides enhance the local inflammatory reaction, the anti-inflammatory and antipyretic effects of α-MSH confer unique properties to this molecule relative to other natural antimicrobial molecules. Synthetic derivatives, chemically stable and resistant to enzymatic degradation, could form the basis for novel therapies that combine anti-inflammatory and antimicrobial properties.

  9. Antimicrobial activity of poly(acrylic acid) block copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Gratzl, Günther, E-mail: guenther.gratzl@jku.at [Johannes Kepler University Linz, Institute for Chemical Technology of Organic Materials, Altenberger Str. 69, 4040 Linz (Austria); Paulik, Christian [Johannes Kepler University Linz, Institute for Chemical Technology of Organic Materials, Altenberger Str. 69, 4040 Linz (Austria); Hild, Sabine [Johannes Kepler University Linz, Institute of Polymer Science, Altenberger Str. 69, 4040 Linz (Austria); Guggenbichler, Josef P.; Lackner, Maximilian [AMiSTec GmbH and Co. KG, Leitweg 13, 6345 Kössen, Tirol (Austria)

    2014-05-01

    The increasing number of antibiotic-resistant bacterial strains has developed into a major health problem. In particular, biofilms are the main reason for hospital-acquired infections and diseases. Once formed, biofilms are difficult to remove as they have specific defense mechanisms against antimicrobial agents. Antimicrobial surfaces must therefore kill or repel bacteria before they can settle to form a biofilm. In this study, we describe that poly(acrylic acid) (PAA) containing diblock copolymers can kill bacteria and prevent from biofilm formation. The PAA diblock copolymers with poly(styrene) and poly(methyl methacrylate) were synthesized via anionic polymerization of tert-butyl acrylate with styrene or methyl methacrylate and subsequent acid-catalyzed hydrolysis of the tert-butyl ester. The copolymers were characterized via nuclear magnetic resonance spectroscopy (NMR), size-exclusion chromatography (SEC), Fourier transform infrared spectroscopy (FTIR), elemental analysis, and acid–base titrations. Copolymer films with a variety of acrylic acid contents were produced by solvent casting, characterized by atomic force microscopy (AFM) and tested for their antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The antimicrobial activity of the acidic diblock copolymers increased with increasing acrylic acid content, independent of the copolymer-partner, the chain length and the nanostructure. - Highlights: • Acrylic acid diblock copolymers are antimicrobially active. • The antimicrobial activity depends on the acrylic acid content in the copolymer. • No salts, metals or other antimicrobial agents are needed.

  10. Immunomodulatory and Antimicrobial Activity of Babassu Mesocarp Improves the Survival in Lethal Sepsis.

    Science.gov (United States)

    Barroqueiro, Elizabeth S B; Prado, Dayanna S; Barcellos, Priscila S; Silva, Tonicley A; Pereira, Wanderson S; Silva, Lucilene A; Maciel, Márcia C G; Barroqueiro, Rodrigo B; Nascimento, Flávia R F; Gonçalves, Azizedite G; Guerra, Rosane N M

    2016-01-01

    Attalea speciosa syn Orbignya phalerata Mart. (babassu) has been used in the treatment of inflammatory and infectious diseases. Aim of the study. To investigate the antimicrobial and immunological activity of babassu mesocarp extract (EE). Material and Methods. The in vitro antimicrobial activity was evaluated by disk diffusion assay and by determination of the minimum inhibitory concentration (MIC) to Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus (MRSA). The flavonoids and phenolic acids content were determined by chromatography. The in vivo assays were performed in Swiss mice submitted to sepsis by cecal ligation and puncture (CLP). The mice received EE subcutaneously (125 or 250 mg/Kg), 6 hours after the CLP. The number of lymphoid cells was quantified and the cytokines production was determined by ELISA after 12 h. Results. EE was effective as antimicrobial to E. faecalis, S. aureus, and MRSA. EE is rich in phenolic acids, a class of compounds with antimicrobial and immunological activity. An increased survival can be observed in those groups, possibly due to a significant inhibition of TNF-α and IL-6. Conclusions. The EE showed specific antimicrobial activity in vitro and an important antiseptic effect in vivo possibly due to the antimicrobial and immunomodulatory activity.

  11. Immunomodulatory and Antimicrobial Activity of Babassu Mesocarp Improves the Survival in Lethal Sepsis

    Directory of Open Access Journals (Sweden)

    Elizabeth S. B. Barroqueiro

    2016-01-01

    Full Text Available Attalea speciosa syn Orbignya phalerata Mart. (babassu has been used in the treatment of inflammatory and infectious diseases. Aim of the study. To investigate the antimicrobial and immunological activity of babassu mesocarp extract (EE. Material and Methods. The in vitro antimicrobial activity was evaluated by disk diffusion assay and by determination of the minimum inhibitory concentration (MIC to Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus (MRSA. The flavonoids and phenolic acids content were determined by chromatography. The in vivo assays were performed in Swiss mice submitted to sepsis by cecal ligation and puncture (CLP. The mice received EE subcutaneously (125 or 250 mg/Kg, 6 hours after the CLP. The number of lymphoid cells was quantified and the cytokines production was determined by ELISA after 12 h. Results. EE was effective as antimicrobial to E. faecalis, S. aureus, and MRSA. EE is rich in phenolic acids, a class of compounds with antimicrobial and immunological activity. An increased survival can be observed in those groups, possibly due to a significant inhibition of TNF-α and IL-6. Conclusions. The EE showed specific antimicrobial activity in vitro and an important antiseptic effect in vivo possibly due to the antimicrobial and immunomodulatory activity.

  12. Immunomodulatory and Antimicrobial Activity of Babassu Mesocarp Improves the Survival in Lethal Sepsis

    Science.gov (United States)

    Prado, Dayanna S.; Barcellos, Priscila S.; Gonçalves, Azizedite G.

    2016-01-01

    Attalea speciosa syn Orbignya phalerata Mart. (babassu) has been used in the treatment of inflammatory and infectious diseases. Aim of the study. To investigate the antimicrobial and immunological activity of babassu mesocarp extract (EE). Material and Methods. The in vitro antimicrobial activity was evaluated by disk diffusion assay and by determination of the minimum inhibitory concentration (MIC) to Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus (MRSA). The flavonoids and phenolic acids content were determined by chromatography. The in vivo assays were performed in Swiss mice submitted to sepsis by cecal ligation and puncture (CLP). The mice received EE subcutaneously (125 or 250 mg/Kg), 6 hours after the CLP. The number of lymphoid cells was quantified and the cytokines production was determined by ELISA after 12 h. Results. EE was effective as antimicrobial to E. faecalis, S. aureus, and MRSA. EE is rich in phenolic acids, a class of compounds with antimicrobial and immunological activity. An increased survival can be observed in those groups, possibly due to a significant inhibition of TNF-α and IL-6. Conclusions. The EE showed specific antimicrobial activity in vitro and an important antiseptic effect in vivo possibly due to the antimicrobial and immunomodulatory activity. PMID:27630733

  13. Antimicrobial effectiveness of silver nanoparticles co-stabilized by the bioactive copolymer pluronic F68

    Directory of Open Access Journals (Sweden)

    dos Santos Carolina Alves

    2012-11-01

    Full Text Available Abstract Background Silver nanoparticles (AgNps have attracted much interest in biomedical engineering, since they have excellent antimicrobial properties. Therefore, AgNps have often been considered for incorporation into medical products for skin pathologies to reduce the risk of contamination. This study aims at evaluating the antimicrobial effectiveness of AgNps stabilized by pluronic™ F68 associated with other polymers such as polyvinyl alcohol (PVA and polyvinylpyrrolidone (PVP. Methods AgNps antimicrobial activity was evaluated using the minimum inhibitory concentration (MIC method. The action spectrum was evaluated for different polymers associated with pluronic™ F68 against the gram negative bacteria P. aeuroginosa and E. coli and the gram positive bacteria S. Aureus. Results AgNps stabilized with PVP or PVA and co-stabilized with pluronic™ F68 are effective against E. coli and P. aeruginosa microorganisms, with MIC values as low as 0.78% of the concentration of the original AgNps dispersion. The antimicrobial action against S. aureus is poor, with MIC values not lower than 25%. Conclusions AgNps stabilized by different polymeric systems have shown improved antimicrobial activity against gram-negative microorganisms in comparison to unstabilized AgNps. Co-stabilization with the bioactive copolymer pluronic™ F68 has further enhanced the antimicrobial effectiveness against both microorganisms. A poor effectiveness has been found against the gram-positive S. aureus microorganism. Future assays are being delineated targeting possible therapeutic applications.

  14. Epidemiology of Staphylococcus aureus in Italy: First nationwide survey, 2012.

    Science.gov (United States)

    Campanile, Floriana; Bongiorno, Dafne; Perez, Marianna; Mongelli, Gino; Sessa, Laura; Benvenuto, Sabrina; Gona, Floriana; Varaldo, Pietro E; Stefani, Stefania

    2015-12-01

    A 3-month epidemiological study to determine the prevalence and antibiotic resistance of Staphylococcus aureus nosocomial infections was performed in 52 centres throughout Italy in 2012. A total of 21,873 pathogens were analysed. The prevalence of S. aureus among all nosocomial pathogens isolated in that period was 11.6% (n=2541), whilst the prevalence of methicillin-resistant S. aureus (MRSA) among the S. aureus was 35.8% (n=910). All tested antimicrobials demonstrated ≥92.2% susceptibility against methicillin-susceptible S. aureus, with the exception of clindamycin (89.7%) and erythromycin (84.2%). Among MRSA, percentages of resistance ranged from 12.6% to >39% for tetracycline, rifampicin, clindamycin and gentamicin; higher percentages were found for erythromycin (65.4%) and fluoroquinolones (72.3-85.8%). Overall, the glycopeptide minimum inhibitory concentration (MIC) distribution showed that 58.3% of strains possessed MICs of 1-2mg/L and few strains were linezolid- or daptomycin-resistant. Molecular characterisation was performed on 102 MRSA selected from Northern, Central and Southern regions. Five major clones were found: Italian/ST228-I (t001-t023-t041-t1686-t3217), 33.3%; USA500/ST8-IV (t008), 17.6%; E-MRSA15/ST22-IVh (t020-t025-t032-t223), 16.7%; USA100/ST5-II (t002-t653-t1349-t2164-t3217-t388), 14.7%; and Brazilian/ST239/241-III (t030-t037), 3.9%. Five PVL-positive CA-MRSA isolates, belonging to USA300 and minor clones, were also identified. In conclusion, this first nationwide surveillance study showed that in Italy, S. aureus infections accounted for 11.6% of all nosocomial infections; MRSA accounted for approximately one-third of the S. aureus isolates and these were multidrug-resistant organisms. Five major MRSA epidemic clones were observed and were inter-regionally distributed, with ST228-SCCmecI becoming predominant.

  15. Multidrug Efflux Pumps in Staphylococcus aureus: an Update.

    Science.gov (United States)

    Costa, Sofia Santos; Viveiros, Miguel; Amaral, Leonard; Couto, Isabel

    2013-01-01

    The emergence of infections caused by multi- or pan-resistant bacteria in the hospital or in the community settings is an increasing health concern. Albeit there is no single resistance mechanism behind multiresistance, multidrug efflux pumps, proteins that cells use to detoxify from noxious compounds, seem to play a key role in the emergence of these multidrug resis