Human resistance to cephalosporin is increasing in Canada as a result of chicken hatcheries robotically injecting them into eggs to stave off infections, the Canadian Medical Association Journal reported.

The finding, a result of surveillance carried out by the Canadian Integrated Program for Antimicrobial Resistance, has also prompted Health Canada to issue a safety warning about cephalosporin, which is not approved for use in chickens or eggs.

CIPARS researchers said they had seen a huge decline in the cephalosporin resistance in salmonella samples taken from humans and retail poultry in 2005, when poultry farmers had stopped using ceftiofur, a type of cephalosporin, following the evidence they had put before the them. Critics, meanwhile, have demanded restrictions or a ban on sale of antibiotics such as cephalosporin for food animal production.