Gram negative organisms with enzymes that confer resistance to 3rd generation cephalosporins in addition to lower order beta-lactams.
Generally, normal GI flora that have a plasmid encoding ESBL.
Community-acquired and nosocomial infections occur, especially if received antimicrobials or have travelled to areas of high prevalence (i.e. Asia/India).
Human-to-human transmission occurs and outbreaks have beed described.
Can also pick up from environment/water, surfaces, animals, and meat!
Asymptomatic colonization, or any syndrome caused by the organism carrying it (see the organism for list)
ESBLs vs. ampC: Most ESBLs are plasmid-encoded, whereas ampCs are usually inducible and chromosomal.
In the lab, ESBLs test susceptible to cefoxitin and cefotetan, and are inhibited by beta-lactamse inhibitors such as tazobactam. They test resistant to aztreonam.