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Abstract Background and Objective: Enterococci are Gram-positive members of human gastrointestinal flora,in Dairy products and environment. they have emerged as important causes of opportunistic nosocomial infections in recent years. In this study we aimed to investigat and compare the efficiency of MALDI-TOFmass spectroscopy method through Biochemical and Molecular methods for detecting Enterococcus faecalis and Enterococcus faecium. Materials and Methods:seventhy five clinical samples were collected for biochemical, molecular and mass spectroscopy investigations. Samples were treated with Esculin hydrolysis, Catalase, Pyrrolidonylaminopeptidase, 6.5% NaCl solution, motility, 0.04% Tellurite, L-Arabinose and Sorbitol. Using specific primesallele specific PCR was used.The samples were then analyzed by MALDI-TOF mass spectroscopy and Biotyper 3 software. Results:Enterococcus faecium andEnterococcus faecaliswere detected in thirty and forty two samples, respectively whereas three samples showed both bacterial infections. Using biochemical analysis, two E.faecium isolates were Arabinose negative and one E. faecalis isolates was Telliurite negative. All sampleswere showed correct bands in PCR results but twoof them didn't show clear bands(on agarose gel). In mass spectroscopy analysis all strains were correctly detected and well defined. Conclusion: According to our results, MALDI-TOF mass spectrometry in comparison with Molecular and Biochemical Methodscould be a reliable and accurate method that can easily and quickly identify and differentiate Enterococcus faecium and Enterococcus faecalisin clinical samples. Key words:Enterococcus faecalis, Enterococcus faecium, MALDI-TOFmass spectrometry,PCR

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Abstract Background and Objective: some of predisposing factors for enterococci colonization are hospitalization in ICU, prolonged use of antibiotics and continued bed rest in hospital. In this study antibiotic resistance of enterococcus in hospitalized patients of four hospitals in Tehran were studied. Material and Methods: the Clinical samples were taken from patients admitted to the ICU, from September 2011 to April 2012. Enterococci isolates were confirmed by biochemical tests, and Enterococcus faecalis and Enterococcus species by species-specific ddl genes. The disk diffusion and micro agar dilution susceptibility tests were performed according to Clinical and Laboratory Standards Institute (CLSI). Results: of 41 isolates in ICUs, 22 (5.52%) were E. faecium and 19 (5.47%) were E. faecalis. Most of E. faecium was isolated from urine and E. faecalis from trachea specimens. The rate of resistance to vancomycin, ampicillin, gentamicin, chloramphenicol and nitrofurantoin in E. faecium isolates was more than that of E. faecalis and the rate of resistance to tetracycline, ciprofloxacin and erythromycin was the same in both of them. MIC50 in vancomycin and ampicillin resistant E. faecium isolates was greater than 256 microgram and the MIC50 in gentamicin resistant isolates was more than 1024 microgram. . Conclusion: The presence of multi-resistant E. faecium strains in ICUs can be a serious warning for physicians and patients. Key words: Enterococcus faecium, Enterococcus faecalis, ICU, Antibiotic Resistance

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Background and objectives: Enterococcus faecium is a normal flora of gut microbiota. This opportunistic pathogen has attracted much attention due to its multidrug resistance and ability to survive in hostile environments. Various molecular typing methods such as pulsed-field gel electrophoresis or ribotyping have been developed for clinical and epidemiological investigation of these bacteria. However, these methods are time-consuming and labor-intensive. The present study was conducted to evaluate the discriminatory power of two common fingerprinting methods i.e. BOX-polymerase chain reaction (PCR) and enterobacterial repetitive intergenic consensus (ERIC)-PCR for E. faecium clinical isolates.
Methods: Fifty multidrug-resistant E. faecium isolates were isolated from 74 clinical specimens. The isolates were identified by specific 16S rRNA PCR. All isolates were fingerprinted using BOX-PCR and ERIC PCR. The discriminatory power and reproducibility of these two methods were also assessed.
Results: According to the dendrogram with >60% similarity, 17 different genotypes were observed using ERIC PCR. In addition, BOX-PCR produced 22 distinct patterns at a genetic distance percentage of 60%, with sizes ranging from 278 bp to 1450 bp. The discrimination index of BOX-PCR was higher than that of ERIC-PCR.
Conclusion: We concluded that a combination of ERIC-PCR and BOX-PCR may be a quicker and more reliable alternative for the discrimination of E. faecium clinical isolates.