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Abstract Background and Objective: Diarrheal diseases may occur in all age groups, worldwide. Escherichia coli (E. coli O157: H7) is one of the most important bacterial agents causing this disease. The purpose of this study was to assess the prevalence of diarrhea in patients with acute diarrhea caused by this bacterium. Material and Methods: In this study, 214 stool samples were collected from acute diarrheic patients in hospitals and clinical laboratories of Malayer city, Iran. The samples were cultured in rich, differentiation, specific and selective medium. To detect E. coli O157: H7, rapid detection method and antisera were used . Results: In 12.15% of the samples, lactose fermentation was observed and E. coli was afirmed. The results of lactose positive samples showed that 6.54% were negative-β- Glucuronidases and were confirmed as E. coli O157. Finally, by using O157: H7 antisera, 1.87% of 14 samples that were negative- β-Glucuronidases were asserted as E. coli O157. Conclusion: based on the results, the prevalence of E. coli O157: H7 is higher in children and elders than the others. Food and water play a significant role in transferring E. coli. Keywords: Prevalence, E. coli O157: H7, Gastroenteritis, Patients

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Background and objectives: Today, the widespread increase in the prevalence of antibiotic resistance in bacteria is considered one of the biggest problems in the health and treatment system around the world. Therefore, this study was conducted with the aim of investigating the prevalence and antibiotic resistance pattern of bacteria isolated from blood cultures of Shahid Rahimi Hospital, Khorramabad in 2018.
Methods: In this cross-sectional study, blood cultures of patients admitted to Shahid Rahimi Hospital from June to December 2018 were investigated. The disc diffusion method was performed according to CLSI instructions. Finally, the data were analyzed using SPSS software.
Results: In the present study, out of a total of 2591 blood culture samples, 247 blood culture samples were positive. The highest frequency was related to the emergency department (62%) and ICU (23%), and the lowest frequency was related to the children's department (2.4%). Among the tested samples, 28% Gram-negative bacilli and 72% Gram-positive cocci were reported. The most abundant Gram-negative and Gram-positive bacteria were Escherichia coli (38%) and Staphylococcus epidermidis (54.2%), respectively. Among Gram-negative bacteria, the highest level of resistance was observed in Acinetobacter baumannii strains, which showed resistance to all antibiotics. Among Gram-positive bacteria, the highest resistance of Streptococcus group D strains to the antibiotic erythromycin (92%) was reported.
Conclusion: The prevalence of antibiotic resistance in common microorganisms isolated from blood cultures in different departments is worrying, and choosing an effective drug to eliminate these bacteria by performing accurate laboratory tests is of particular importance.