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A Study of Scanning Electron Microscope of Vancomycin Resistant Enterococcus faecalis from Clinical Isolates  [PDF]
Ajay Kumar Oli, Raju Sungar, Nagaveni Shivshetty, Rajeshwari Hosamani, Kelmani Chandrakanth Revansiddappa
Advances in Microbiology (AiM) , 2012, DOI: 10.4236/aim.2012.22012
Abstract: Vancomycin-resistant Enterococcus faecalis pose an emerging health risk, but little is known about the precise epidemiology for vancomycin resistance. The glycopeptide resistant was studied using different techniques such as broth macrodilution, agar dilution combined with agar diffusion, morphology cell changes by scanning electron microscopy. Eight VREF isolated from different clinical samples were used. Results showed low level and high level resistant to vancomycin antibiotic at concentration of 64 to 128 μg/ml, but antibacterial activity was reduced to 256 μg/ml, the SEM revaled increased in the cell size with the antibiotic compared to control and standard culture. The technique constitutes simple method for the detection of organism.
In vitro fosfomycin activity in vancomycin-resistant Enterococcus faecalis
Superti, Silvana;Dias, Cícero Armídio Gomes;d'Azevedo, Pedro Alves;
Brazilian Journal of Infectious Diseases , 2009, DOI: 10.1590/S1413-86702009000200010
Abstract: enterococci are part of the endogenous flora of human beings, are naturally resistant to several classes of antimicrobials, and are able to acquire resistance with relative ease. currently the vancomycin-resistant enterococci are spread all over the world and treatment options for infections caused by it are often extremely limited. we assessed 193 vancomycin-resistant enterococcus faecalis isolates collected from four different hospitals in porto alegre for their susceptibility to fosfomycin using the e-test and agar diffusion. fosfomycin proved to be active in vitro against the great majority of isolates, indicating that it is a valid option in the treatment of these infections.
Emergence and characterisation of vanB vancomycin-resistant Enterococcus faecalis in Rio de Janeiro, Brazil
Merquior, Vania Lúcia Carreira;Faria, Adriana Rocha;Rocha, Filomena Soares Pereira da;Morais, Jaqueline Martins;Neves, Felipe Piedade Gon?alves;Teixeira, Lúcia Martins;
Memórias do Instituto Oswaldo Cruz , 2012, DOI: 10.1590/S0074-02762012000400020
Abstract: here we describe the detection and characterisation of three isolates of vancomycin-resistant vanb-type enterococcus faecalis. sequence analysis suggested that these isolates harboured the vanb1 gene. the isolates were susceptible to the majority of antimicrobial agents tested, with the exception of chloramphenicol, erythromycin and vancomycin, and showed distinct profiles of high-level resistance to aminoglycosides. analysis of the clonal relatedness of the vanb e. faecalis isolates showed similar pulsed-field gel electrophoresis profiles. to our knowledge, this is the first report of the occurrence of enterococcal strains carrying vanb genes in brazil.
Identification and molecular characterization of Van A-type vancomycin-resistant Enterococcus faecalis in Northeast of Brazil
Vilela, Marinalda Anselmo;Souza, Sandra Lavareda de;Palazzo, Izabel Cristina Vanzato;Ferreira, Joseane Cristina;Morais Jr, Marcos Antonio de;Darini, Ana Lúcia da Costa;Morais, Márcia Maria Camargo de;
Memórias do Instituto Oswaldo Cruz , 2006, DOI: 10.1590/S0074-02762006000700002
Abstract: the isolation of vancomycin resistant enterococci (vre) in brazil has rapidly increased, following the world wide tendency. we report in the present study the first isolation of vancomycin resistant enterococcus faecalis (vre) in the northeast of brazil. the four vre isolates were characterized for antimicrobial susceptibility, genotypic typing by macro restriction of chromosomal dna followed by pulsed-field gel electrophoresis and for characterization of the tn1546-like element and plasmid contents. the isolates showed resistance to multiple antibiotics and a single genotype profile, suggesting the dissemination of a single clone among the patients. tn1546 associated to genetic elements as plasmids shows the importance of infection control measures to avoid the spreading of glycopetide resistance by conjugative transfer of vana elements.
Unusual Increase of Vancomycin-resistant Enterococcus faecium but not Enterococcus faecalis at a University Hospital in Taiwan  [PDF]
Ping-Cherng Chiang,Tsu-Lan Wu,Jiunn-Yih Su,Yhu-Chering Huang
Chang Gung Medical Journal , 2007,
Abstract: Background: Enterococcal infections at the Chang Gung Memorial Hospital, Taiwan, haveincreased significantly in recent years, accompanied by a significant growth ofvancomycin resistance from < 1% to 3.8%. However, the significant increase invancomycin resistance was only found in Enterococcus faecium (from 0.5% to17.4%).Methods: A total of 172 patients infected with vancomycin-resistant enterococci (85 E.faecium and 87 E. faecalis) during 1998-2004 were retrospectively studied.Clinical and laboratory features were analyzed using Stata for Windows (version8.2). Genotypes of the isolates were determined by infrequent-restriction-site polymerase chain reaction.Results: Multivariate analysis revealed that prior use of imipenem (odds ratio [OR],30.1; 95% confidence interval [CI], 4.2-215.9) or clindamycin (OR, 6.5; 95%CI, 1.5-28.1), positive urine cultures (OR, 6.1; 95% CI, 2.1-17.8) and penicillinresistance (OR, 55.9; 95% CI, 18.5-168.3) were significantly associatedwith the infections caused by vancomycin-resistant E. faecium.Genotyping analysis demonstrated a predominant genotype in 71 (83.5%) ofthe E. faecium isolates, while diverse genotypes were found among the E.faecalis isolates. No apparent correlation between genotype and any specificward was found. Up to the end of 2005, primary efforts to restrict imipenemusage and reinforce infection control measures have reduced by half theinfections caused by vancomycin-resistant E. faecium.Conclusion: Multiple factors were associated with the unusual increase of vancomycinresistantE. faecium infections in this hospital. Continuous monitoring ofappropriate antimicrobial usage and stringent compliance to infection controlmeasures are required to control the increase of such infections.
Study on the susceptibility of Enterococcus faecalis from infectious processes to ciprofloxacin and vancomycin
Genaro, A.;Cunha, M. L. R. S.;Lopes, C. A. M.;
Journal of Venomous Animals and Toxins including Tropical Diseases , 2005, DOI: 10.1590/S1678-91992005000300004
Abstract: enterococcus faecalis is considered a pathogen responsible for hospital infections and, due to its frequent multi-resistant profile, has caused preoccupations among many medical authorities. the objective of this study was to determine the antimicrobial susceptibility of 74 strains isolated from blood cultures and purulent secretions to vancomycin and ciprofloxacin through the minimum inhibitory concentration (mic) and minimum bactericidal concentration (mbc) by using the microdilution test. the results showed a greater efficacy of vancomycin compared to ciprofloxacin (98.6% of the strains were inhibited by vancomycin at lower concentrations: 0.06 - 1 μg/ml). however, in the mbc analysis 73% of the strains showed a mbc of vancomycin only at high concentrations (equal to or higher than 64 μg/ml). for ciprofloxacin, the strains showed a broad sensitivity with mics and mbcs distributed along all the mic classes. results also revealed a probability that some strains are tolerant to vancomycin, which indicates the need of other tests to confirm this characteristic.
Vancomycin-resistant van a phenotype Enterococcus faecalis: first case in Minas Gerais state and epidemiological considerations
Ribas, Rosineide Marques;Darini, Ana Lúcia da Costa;Moreira, Tomaz Aquino;Freitas, Claudete;Gontijo Filho, Paulo P.;
Brazilian Journal of Infectious Diseases , 2007, DOI: 10.1590/S1413-86702007000400015
Abstract: we report the first case of vancomycin-resistant enterococcus faecalis with vana phenotype and vana genotype isolated from a surgical patient in a general hospital in uberlandia, state of minas gerais, brazil.
Virulence factors in vancomycin-resistant and vancomycin - susceptible Enterococcus faecalis from Brazil
Camargo, I. L. B. C.;Zanella, R. C.;Gilmore, M. S.;Darini, A. L. C.;
Brazilian Journal of Microbiology , 2008, DOI: 10.1590/S1517-83822008000200014
Abstract: enterococci are members of commensal flora of animals and insects, but are also important opportunistic pathogens. our objective was to observe if there was any difference of virulence in several groups of e. faecalis, mainly between vancomycin-resistant e. faecalis (vrefs) of colonization and infection. vrefs and vancomycin-sensitive e. faecalis from brazil were screened for the presence of virulence factor genes. phenotypic assays were used to assess in vitro expression, to understand the pathogenic potential of these isolates and to determine whether a correlation exists between virulence and antibiotic resistance. different virulence profiles were found suggesting that the disseminating clone may have generated several variations. however, our study showed that one constellation of traits appeared most commonly: gelatinase, aggregation substance and esp (gea). these factors are important because they have been implicated in cell aggregation and biofilm formation. biofilm formation may promote the conjugation of plasmids harboring resistance and virulence genes, enhancing the probability of entry of new resistance genes into species. curiously, the profile gea was not exclusive to vrefs, it was the second most observed in vsefs isolates from colonization and infection in hospitalized patients and also from rectal swabs of healthy volunteers. such strains appear to represent the entry gateway to new resistance genes into e. faecalis and may contribute to the spreading of e. faecalis mainly in hospitals.
First report of vancomycin-resistant Enterococcus faecalis in Uberaba, Minas Gerais state
Concei??o, Natália;Darini, Ana Lúcia da Costa;Palazzo, Izabel Cristina Vanzato;Oliveira, Cristina da Cunha Hueb Barata de;Oliveira, Adriana Gon?alves de;
Brazilian Journal of Microbiology , 2010, DOI: 10.1590/S1517-83822010000100007
Abstract: in this study we report the first isolation of vana-type vancomycin-resistant enterococcus faecalis strains from two different patients hospitalized in the same intensive care unit at the hospital of universidade federal do triangulo mineiro (uftm), uberaba, minas gerais, brazil.
Vancomycin-Resistant Enterococcus faecalis from a Wastewater Treatment Plant in Tabriz, Iran  [PDF]
E.B. Gajan,R. Abashov,M. Aghazadeh,H. Eslami
Pakistan Journal of Biological Sciences , 2008,
Abstract: The aim of this study was to determine the resistance pattern and the type of resistance genes of vancomycin-resistant Enterococcus faecalis from Gharamalek wastewater treatment plant in Tabriz, Iran. Following filtering of sewage samples, approximately 300 colonies grew on specific media, of which 53 were randomly selected and purified using 0.45 μm membranes. The membranes were placed on culture media containing antibiotics to isolate the vancomycin-resistant Enterococcus. Biochemical tests, antibiogram and determining minimum inhibitory concentration of antibiotics with E-test including vancomycin were performed. Polymerase Chain Reaction (PCR) was carried out to determine the type of resistance genes. All tested samples were found to be E. faecalis. Antimicrobial susceptibility tests indicated multidrug resistance in the sapmles, with 98% of them highly resistant to vancomycin. The highest frequency was of vanA (96%), followed by vanB (4%); vanC was not seen among the tested samples. The results confirmed that the risk of exposure to antibiotic-resistant pathogens from the evaluated urban wastewater is considerable.
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