Sir, The predominant cause of resistance towards cephalosporins in Escherichia coli is production of plasmid-encoded extended-spectrum ß-lactamases (ESBLs) and AmpC-type ß-lactamases, also referred to as extended-spectrum cephalosporinases (ESCs). Most studies have focused on description of ESCs in bacteria from humans as well as production animals, while fewer studies have focused on the prevalence of ESCs in bacteria from imported food products.