Tehran University of Medical Sciences Journal of Medical Bacteriology 2251-8649 3 1-2 2015 10 13 28 35 EN Nastaran Agha-Moghaddam Pasteur Institute of Iran, Department of Microbiology, Tehran, IR Iran. Seyed Mohammad Mahdi Hosseini-Moghaddam Urology and Nephrology Research Center (UNRC), Shaheed Beheshti University of Medical Sciences, Tehran, IR Iran. Malihe Talebi Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, IR Iran. Mohammad Reza Pourshafie Pasteur Institute of Iran, Department of Microbiology, Tehran, IR Iran. 2015 10 12 Background: The objectives of this study were to assess the antibiotic resistance and clonality of the bacteria isolated from patients with long- (LTC) and short-terms catheterizations (STC). Methods: A total of 31 clinical Staphylococcus aureus isolates were collected from Loghman Hospital of Tehran, Iran. In vitro biofilm formation ability was determined by microliter tissue culture plates. All clinical isolates were examined for determination the ica locus by using PCR method. Results: Ninety seven (62%) of the samples were bacterial positive. Positive samples were significantly higher in LTC (95%) than STC (61%) patients. Escherichia coli were the predominant microorganism (32%) followed by Klebsiella pneumoniae (15%), Pseudomonas aeroginosa (11%), Enterococcus faecalis (9.2%). From the total isolates, 42% were resistant to 5 or more antibiotics. Furthermore, high prevalence of resistance amongst all isolates to ciprofloxacin (49%) was observed. Conclusions: Diverse bacterial clones were observed for LTC and STC patients. Overall, the results suggested that catheterization could be a major source for growth and dissemination of highly resistant and diverse bacterial species in the hospitals. https://jmb.tums.ac.ir/index.php/jmb/article/view/16 https://jmb.tums.ac.ir/index.php/jmb/article/download/16/49