Phenotypic cofirmatory disc diffusion test (PCDDT), double disc synergy test (DDST), e-test os diagnostic tool for detection of extended spectrum beta lactamase (ESβL) producing uropathogens

The aim of this study was to probe the best diagnostic tool for the detection of Extended Spectrum β –lactamase (ESβL) producing uropathogen and their antimicrobial susceptibility profile to treat the infections properly.

Clinical samples of urine were cultured on Cysteine Lactosse Electrolyte Deficient (CLED) Agar medium. Antimicrobial sensitivity tests were carried out by Kirby-Bauer disc diffusion method. Phenotypic methods were used for further confirmation of β-lactamase production by phenotypic confirmatory disc diffusion test (PCDDT), doubble disc synergy test (DDST) and by E-test for ESBL production. Aswab on Mueller-Hinton (MH) agar plates was used for further studies and the Optical Density (O.D.) of the cultures was set to 0.1 (at 530 nm).

Sample size N= 200 was selected from patients suffering from UTI. Out of the 200 samples, n=141 samples yielded Aerobic Gram Negative Bacteria (AGNB). The commonest organism isolated was E.coli n=108, best antimicrobial result of 95% was shown by imipenem. Among the AGNB isolates, 20 organisms (12.98%) were ESBL producers. E.coli showed highest ESBL production of 85%. The most effective antimicrobial in ESBL producers was Imipenem (84%) Augmentin was least sensitive (05%).

ESBL prooduction is a common phenomenon in UTI patients and screening by DDST for these enzymes is a good epidemiological tool to assess the overall situation in a certain setup. It was also seen that Imipenem (Carbapenem) is the drug of choice.