fa بررسی اثر هم افزایی سیپروفلوکساسین بر پیپراسیلین، سفتازیدیم و ایمی پنم بر آنتروکوک‌ها کارآزمایی بالینی Clinical Trials <p>Background and Objective: Attention has largely been focused on appearance of multiple drug resistance enterococci in the last 20 years. One of the methods to overcome this problem is to combine different antibiotics in order to increase antimicrobial activity and reduce toxicity. The combination of fluor quinolones with other antibiotics has been widely investigated. The aim of this study was to investigate the synergistic effect of ciprofloxacin in several antibiotics Beta-lactam (piperacillin, ceftazidime and imipenem) on isolated enterococci. Materials and Methods: In this cross sectional study, 67 Streptococci strains were isolated from clinical samples from March to September 2012. The serial broth dilution method in test tubes was used for the MIC, and the check board Format was used for the synergistic effect of ciprofloxacin with Beta-lactam antibiotics. The synergistic effect was determined with four- fold reduction of initial MIC. Results: Totally, 67 strains of Streptococci were used, in which 50 strains (74.6%) were enterococci, 6(9%) were group B streptococcus, 5(7.5%) were non-group A streptococci, 2 (3%) were pneumococci, and 2 were strains of alpha streptococci (3%), respectively. All results were determined by the MIC and MBC of each antibiotic individually and also in combination with ciprofloxacin. Conclusion: The effect of ciprofloxacin on other antibiotics was indifferent, and the synergistic effect was not observed.</p> Keywords: Enterococcus, Streptococcus, Synergism, Ciprofloxacin, Beta- lactam, MIC, MBC 23 32 http://journal.zums.ac.ir/browse.php?a_code=A-10-4-782&slc_lang=fa&sid=1 Mohmmad mehdi Soltan Dallal محمد مهدی سلطان دلال soltanirad34@yahoo.com 5200319475328460059279 5200319475328460059279 Yes 1,2Food Microbiology Research Center, Tehran University of Medical Sciences, Tehran, Iran ,Division of Microbiology, Dept. of Pathobiology, School of Public Health, Tehran University of Medical Sciences. Tehran, Iran.. Abdolaziz Rastegar Lari عبدالعزیز رستگار لاری 5200319475328460059280 5200319475328460059280 No Antimicrobial Resistant Research Center, Tehran University of Medical Sciences, Tehran, Iran. Ronak Bakhtiari روناک بختیاری 5200319475328460059281 5200319475328460059281 No Division of Microbiology, Dept. of Pathobiology, School of Public Health, Tehran University of Medical Sciences. Tehran, Iran. Bahram Nikmanesh بهرام نیک منش 5200319475328460059282 5200319475328460059282 No Laboratory, Children’s Medical Center, Tehran University of Medical Sciences, Tehran, Iran MohammadKazem Sharifi Yazdi محمدکاظم شریفی یزدی 5200319475328460059283 5200319475328460059283 No 5,6Zoonosis Research Center, Tehran University of Medical Sciences, Tehran, Iran ,Dept. of Medical Laboratory Sciences, School of Para Medicine, Tehran University of Medical Sciences. Tehran, Iran..