Dr.Bitew, Adane(Phd, Associate professor)Sodere, Seble2020-05-212023-11-062020-05-212023-11-062019http://etd.aau.edu.et/handle/123456789/21289Background:Bloodstream infection is one of the most important causes of morbidityand mortality globally. Staphylococcus aureus, coagulase negative staphylococci ,Streptococcus pneumonia are major Gram- positive bacteria in causing blood stream infectionEscherichia coli,Klebsiellapneumoniae, Pseudomonas aeruginosa,Acinetobacterbaumannii are major Gramnegative bacteria in causing blood stream infections. Development of multidrug resistance in major bacteria has increased the morbidity and mortality rate of blood stream infection. Objective: To assess the distribution of bacteria implicated in causing blood stream infections and prevalence of their multidrug resistance profile and Extended spectrum betalactamase production. Method: The present study was a laboratory based cross-sectional study conducted at Arsho Advanced Medical laboratory, Addis Ababa, Ethiopia from January to April 2019; A total of 422 blood samples was collected and inoculated on to primary isolation culture following standards protocols. Species identification and antimicrobial susceptibility testing of bacteria were determined by automated Vitek2 compact system (bio Merieux, France) using AST, GN72 card for gram negatives and AST,GP71 card for gram positive bacteria. Result :Out of a total of 422 samples processed, bacterial pathogens were isolated from 89(21.1%) samples. Among the isolates, 52 were Gram- positive and 37 were Gram negative bacteria.Coagulasenegative staphylococci and Klebsiellaspp were the dominant isolates. Penicillin (92.3%) was the least effective antibiotic against Gram-positive bacteria while cephalotin (91.1%) and cephazolin (89.2%) were the least effective antibiotic against Gramnegative bacteria. Linzolid and Tigcyclne(98.1%) were the most effective antibiotic against Gram positive and piperacillin(86.1%) were the most effective antibiotic against Gram-negative bacteria, Out of 52 isolate of Gram-positive bacteria 30(57.7%) were MDR and out of 37 isolates of gram negative bacteria 20(54%) were MDR. Conclusion:The magnitude of blood stream bacterial infection and the prevalence rate of multidrug resistant bacterial strains causing blood stream infections were high. These findings warranted the need for continuous investigations bacterial blood stream infection.en-USBacterial etiology ,multidrug resistance , extended beta lactamase production,bloodstream infections,Thesis