β-lactamase disk test; A: (Lawn culture) P. aeroginosa ATCC 27853, B: (TE buffer containing blank disk, dipped with clinical isolates and cefotaxime disk in the middle) ESBLs producing clinical isolates, C &amp; D: negative control; E.coli ATCC 25922 and P. aeroginosa ATCC 27853. ESBLs production by clinical isolates causes changes in the growth inhibition zone form (clover leaf figure) around the cefotaxime disk.