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Microbial Resistance (microbial + resistance)
Selected AbstractsAntimicrobial profiles of periodontal pathogens isolated from periodontitis patients in the Netherlands and SpainJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 8 2005A. J. Van Winkelhoff Abstract Background and Aim: Antimicrobial resistance of periodontal pathogens towards currently used antibiotics in periodontics has been investigated in a previous study. Microbial resistance in the periodontal microflora was more frequently observed in Spanish patients in comparison with Dutch patients. The aim of the present study was to compare antimicrobial susceptibility profiles of five periodontal bacteria isolated from periodontitis patients in Spain and in the Netherlands. Material and Methods: Subgingival plaque samples from adult patients with periodontitis were collected and cultured on selective and non-selective plates. Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum and Micromonas micros were isolated and used for minimal inhibitory concentration tests using the Epsilometer (E-test) technique. Eight different antibiotics were tested on all bacterial isolates. MIC50 and MIC90 values for each antibiotic and each species were determined and the percentage of resistant strains was calculated. Results: Significantly higher MIC values were noted in Spanish strains of F. nucleatum for penicillin, ciprofloxacin, of P. intermedia for penicillin, amoxicillin and tetracycline, of M. micros for tetracycline, amoxicillin and azithromycin, and of P. gingivalis for tetracycline and ciprofloxacin. Based on breakpoint concentrations, a higher number of resistant strains in Spain were found in F. nucleatum for penicillin, amoxicillin and metronidazole, in Prevotella intermedia for tetracycline and amoxicillin, and in A. actinomycetemcomitans for amoxicillin and azithromycin. Resistance of P. gingivalis strains was not observed for any of the antibiotics tested both in Spain and the Netherlands. Conclusions: Differences exist in the susceptibility profiles of periodontal pathogens isolated from periodontitis patients in Spain and in the Netherlands. This implicates that antibiotic susceptibility testing is necessary to determine efficacy of antimicrobial agents. Also, clinical studies with antibiotics should take these differences into account. The information from the present study indicates that it may not be possible to develop uniform protocols for usage of antibiotics in the treatment of severe periodontitis in the European Union. [source] Coselection for microbial resistance to metals and antibiotics in freshwater microcosmsENVIRONMENTAL MICROBIOLOGY, Issue 9 2006Ramunas Stepanauskas Summary Bacterial resistances to diverse metals and antibiotics are often genetically linked, suggesting that exposure to toxic metals may select for strains resistant to antibiotics and vice versa. To test the hypothesis that resistances to metals and antibiotics are coselected for in environmental microbial assemblages, we investigated the frequency of diverse resistances in freshwater microcosms amended with Cd, Ni, ampicillin or tetracycline. We found that all four toxicants significantly increased the frequency of bacterioplankton resistance to multiple, chemically unrelated metals and antibiotics. An ampicillin-resistant strain of the opportunistic human pathogen Ralstonia mannitolilytica was enriched in microcosms amended with Cd. Frequencies of antibiotic resistance were elevated in microcosms with metal concentrations representative of industry and mining-impacted environments (0.01,1 mM). Metal but not antibiotic amendments decreased microbial diversity, and a weeklong exposure to high concentrations of ampicillin (0.01,10 mg l,1) and tetracycline (0.03,30 mg l,1) decreased microbial abundance only slightly, implying a large reservoir of antibiotic resistance in the studied environment. Our results provide first experimental evidence that the exposure of freshwater environments to individual metals and antibiotics selects for multiresistant microorganisms, including opportunistic human pathogens. [source] Prevention of respiratory infections in the elderlyGERIATRICS & GERONTOLOGY INTERNATIONAL, Issue 3 2002Mutsuo Yamaya The risk of nosocomial infections is 3,5-fold higher among older patients than among younger adults. Both the increased incidence of respiratory infections and the high mortality among older people are a consequence of a number of age-related factors, including coexisting illnesses, therapeutic interventions, and the aging process itself. Risk factors for the development of respiratory infections in older people can be broadly classified into factors that alter host defenses and factors that increase exposure to bacteria. These factors combine to adversely affect the person's capacity to defend against pathogens of the upper and lower respiratory tract. Despite the availability of potent new antimicrobials, the increasingly limited treatment efficacy of these antimicrobials is related to emerging microbial resistance. Recently, new methods of treating respiratory infections according to the mechanisms of infection have been introduced. Effective methods of preventing respiratory infections in older people were reviewed. [source] The model of fungal population dynamics affected by nystatinINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 1 2010Sergei I. Voychuk Abstract Fungal diseases are acute problems of the up-to-day medicine. Significant increase of resistance of microorganisms to the medically used antibiotics and a lack of new effective drugs follows in a growth of dosage of existing chemicals to solve the problem. Quite often such approach results in side effects on humans. Detailed study of fungi-antibiotic dynamics can identify new mechanisms and bring new ideas to overcome the microbial resistance with a lower dosage of antibiotics. In this study, the dynamics of the microbial population under antibiotic treatment was investigated. The effects of nystatin on the population of Saccharomyces cerevisiae yeasts were used as a model system. Nystatin effects were investigated both in liquid and solid media by viability tests. Dependence of nystatin action on osmotic gradient was evaluated in NaCl solutions. Influences of glucose and yeast extract were additionally analyzed. A "stepwise" pattern of the cell death caused by nystatin was the most intriguing. This pattern manifested in periodical changes of the stages of cell death against stages of resistance to the antibiotic. The mathematical model was proposed to describe cell-antibiotic interactions and nystatin viability effects in the liquid medium. The model implies that antibiotic ability to cause a cells death is significantly affected by the intracellular compounds, which came out of cells after their osmotic barriers were damaged © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010 [source] Adaptive drug resistance mediated by root,nodulation,cell division efflux pumpsCLINICAL MICROBIOLOGY AND INFECTION, Issue 2009C. Daniels Abstract Bacterial resistance to antibiotics is a major therapeutic problem. Bacteria use the same mechanisms for developing resistance to antibiotics as they do for developing resistance to biocide compounds present in some cleaning and personal care products. Root,nodulation,cell division (RND) family efflux pumps are a common means of multidrug resistance, and induction of their expression can explain the observed cross-resistance found between antibiotics and biocides in laboratory strains. Hence, there is a relationship between the active chemicals used in household products, organic solvents and antibiotics. The widespread use of biocide-containing modern-day household products may promote the development of microbial resistance and, in particular, cross-resistance to antibiotics. [source] All EU hands to the EU pumps: the Science Academies of Europe (EASAC) recommend strong support of research to tackle antibacterial resistanceCLINICAL MICROBIOLOGY AND INFECTION, Issue 10 20082Article first published online: 15 SEP 200, I. C. Gyssens Abstract Despite many European Union (EU) conferences on fighting microbial resistance, rates of resistance in Europe continue to increase. Although research is catching up with discovery, the development of new antimicrobials is threatened by economic factors, in particular the need for a return of investment via high-volume sales. The EU should invest in independent research into the economic and business aspects of antibiotic development. Multidisciplinary input from the fields of finance, law, marketing, sociology and psychology will inform a broad agenda for change at the regulatory, academic and commercial levels and identify new options for novel anti-infective research and development, as recently recommended by the Science Academies of Europe (EASAC). [source] | ||||||||||