Background: P. aeruginosa is the most common nosocomial pathogen encountered and a known organism causing high mortality and morbidity. Due to indiscriminate antibiotic use, resistance is very commonly known in them and ESBL enzyme production being the most predominant one. Material and Methods: A total of Ninty isolates of P. aeruginosa were tested for the presence of ESBL enzyme by both disc diffusion and double disc synergy test. Antibiotic sensitivity pattern of ESBL-positive P. aeruginosa was determined. Results: Of the 1200 pus samples screened, 90 isolates of pseudomonas were tested for ESBL production. Of the 90 P.aeruginosa isolates, 57 (63%) were sensitive to 3GC and 33 (37%) were resistant.Of the 33 P.aeruginosa resistant to ceftazidime, DDT detected 9 (27%) of ESBL producers and DDST detected 17 (51%). And 17 (51%) did not show ESBL production by either of the methods used in the study. All the ESBL-positive P. aeruginosa were multi-drug resistant, with 100% sensitivity to imipenem; followed by ofloxacin (70%). Conclusion: From this study, we conclude that DDST proved to be better method than DDT to detect ESBL producing P. aeruginosa. However in the absence of any CLSI guidelines for detection of ESBL in Non-fermenters, we reframe from commenting on specificities of either of tests. There is a strong need for standardization/ CLSI guidelines for detection.

Keywords: Third Generation Cephalosporins; Double Disk Synergy Test; Disc Diffusion Test; P. Aeruginosa.