1983. These enzymes possess the ability to inactivate susceptible ?-lactam antibiotics i.e. penicillins, first, second and third generation cephalosporins aztreonam, but not cephamycins carbapenems . Their mode of action is by hydrolyzing ring. Even before first antibiotic (penicillin) was developed, resistance observed ESBL genes are plasmids- transposons- mediated, as such, can be spread easi...