Abstract:
 Objective: To determine the occurrence of Extended-spectrum β-lactamase (ESBL) producing gram negative bacteria (GNB) and their sensitivity patterns in a tertiary care hospital.
 Methods: In this cross-sectional study, conducted in the Microbiology section of Pathology lab, in a tertiary care hospital Lahore, various specimens such as blood, body fluids, urine, and pus were included during a period starting from October 2020 till September 2021. The samples having growth of gram negative bacteria were processed further for determination of ESBL production. After isolation, antimicrobial susceptibility pattern was determined for each isolate.
 Results: GNB were isolated from 130 samples, among those 46 (35.4%) were labelled as ESBL. The commonest ESBL producing bacteria was E. coli, followed by pseudomonas aeruginosa found in 17.39% samples. In E. Coli, Imipenem (IPM) showed highest sensitivity of 84.8%, other sensitive drugs were Amikacin (AK), gentamicin (CN), and Tazobactam-piperacillin(TZP). For Pseudomonas aeruginosa, Imipenem and Tazobactam-piperacillin showed sensitivity of 75%, AK and CN were 50% sensitive. Against Klebsiella pneumoniae , IPM was 100% sensitive, AK and TZP were 85.7% sensitive. IPM, CN, and AK were 100% sensitive against Morganella morganii. AK and CN were 100% sensitive against Citrobacter species.
 Conclusion: It was concluded that, there was significant prevalence of ESBL producing strains amongst Gram negative bacterial infections. E. Coli and Pseudomonas aeruginosa were the commonest ESBL producers. IPM, AK, and TZP were sensitive against majority of the ESBL producing GNB.