10.22376/ijpbs.2019.10.1.p1-12 Volume 7 Issue 4 2016 (October - December) Routine detection of AmpC beta lactamases in lessThan i greaterThan Escherichia coli lessThan /i greaterThan is cumbersome. This study was performed to determine the usefulness of a modified disc diffusion test to detect AmpC beta lactamases in lessThan i greaterThan E.coli lessThan /i greaterThan . 28 non-repetitive, cefoxitin resistant isolates of lessThan i greaterThan E.coli lessThan /i greaterThan were collected from cases of urinary tract infections and screened phenotypically for ESBLs and AmpC beta lactamase using DDST (ceftazidime and ceftazidime-clavulanic acid for detection of ESBLs, cefoxitin-cloxacillin DDST and cefoxitin - phenylboronic acid, cefoxitin-EDTA combination discs). Genotypic detection of AmpC and ESBL genes was done by PCR along with mutation analysis of chromosomal promoter of AmpC. Of the 28 isolates, 6 strains showed enhancement of zone of inhibition in cefoxitin-cloxacillin, cefoxitin plus 400mcg of phenyl boronic acid and a combination of 400 mcg of phenyl boronic acid and 292 mcg of EDTA but not with EDTA alone. Of the 6 phenotypically AmpC beta lactamase positive strains, 4 carried plasmid AmpC beta lactamase gene. MAANASA BHASKAR M AND JHARNA MANDAL Antibiotics, Escherichia coli, ESBL, AmpC beta lactamases, DDST 579-583