ABSTRACTObjective: Nosocomial infections or Hospital acquired infection (HAI) are one of the major threats to hospitalized patients as well as for the hospitalassociated personnel. In last few years there is a gross change in causative agents, new organisms have come out with great threat to hospitals as theypossess antibiotic resistance property e.g. production of biofilm, production of enzymes such as β- lactamases. Among many organisms, Acinetobacterbaumannii has emerged as a potent nosocomial pathogen. Our objective of this study was to find the burden of Acinetobacter baumannii infectionswhich are associated as nosocomial infections and to determine the drug of choice for an effective treatment.Methods: Clinical specimens were collected from patients of different unit of the hospital by maintaining universal precautions and standardmicrobiological protocols. All the respective specimens were cultured in respective culture medium i.e. MacConkey agar, blood agar, chocolate agar,cysteine lactose electrolyte deficient (CLED) agar and, fluid thioglycolate (TG) medium at 37˚C for 24-48 hours. After incubation of 24-48 hours cultureplates were examined for bacterial growth and identification and antibiotic sensitivity test was made by Vitek2 compact.Result: The study was conducted at the department of microbiology from January 2016 to April 2016. A total of 2582 specimens were collected andprocessed for identification and sensitivity testing. Specimens of all age group (2 days- 93 years) and both sexes were processed for identificationof A. baumannii and antibiotic sensitivity testing. A total of 119 isolates (4.60%) of A. baumannii were obtained from 2582 clinical specimens. Themost common infection A. baumannii was found as lower respiratory tract infection (89.07%) followed by abscess (6.72%), septicaemia (2.52%),urinary tract infections (0.84%), and soft tissue infections (0.84%). The maximum sensitivity of A. baumannii isolates were seen to Colistin (CL) (119,100%), followed by Tigecycline (TGC) (63, 52.94%) and Minocycline (MIN) (27, 22.69%). The maximum resistant was observed for Imipenem (IMI),Aztreonam (AZT) and Ticarcillin- clavulanic acid (TIC) (119, 100%).Conclusion: The Gram- negative coccobacillus, Acinetobacter baumannii poses a formidable threat to patients. It has emerged as a superbug inhospital environment particularly in ICU units. The chances of A. baumannii infections increase in the presence of iatrogenic factors like inadequatelong- term antibiotic therapy and new interventions in a medical facility. To control the burden of Acinetobacter infections new therapies suchas combine therapy must be obtained and followed with proper dose as recommend by physicians; along with awareness of the importance ofthis infection should be implicated. Proper sanitation, good housekeeping, sterilization of equipment, hand hygiene, water purification, isolationprocedures and maintaining of the hospital environment, use of infection control practices are some of the measures to control the transmission ofAcinetobacter spp. among hospital personnel.Keywords: Acinetobacter baumannii, Biofilm, β-lactamases, Hospital acquired infection