Carbapenem resistance serious health threat

carbapenem resistant bacteria and enzymes have been isolated from poultryIn the fight against antibiotic resistance there is major concern about the development of resistance of gram-negative bacteria to one of the antibiotics of last resort, the carbapenems. Carbapenems, such as Imipenem, Meropenem, Ertapenem and Doripenem, are broad spectrum antimicrobial agents, which means they can combat many different bacterial infections. They are mostly used for the treatment of serious infections with gram-negative bacteria in humans, for example infections with Klebsiella pneumonia.

Most of the carbapenem resistant bacteria produce carbapenemases (CP), enzymes that are capable of breaking down this type of antibiotics. Other gram-negative bacteria are not susceptible to carbapenems because of other mechanisms. Usually the resistant bacteria are already resistant to a range of important antimicrobials, leaving few therapeutic options. Especially the emergence and spread of Enterobacteriaceae that are either non-susceptible to carbapenem or able to produce the enzyme are a major public health threat.

Routes of transmission

One of the routes of transmission is through food-producing animals and preparation and consumption of food of animal origin. Only few data are available on the occurrence of CP-producing bacteria in livestock. The European Food Safety Authority (EFSA) recently published a Scientific Opinion on carbapenem resistance in food animal ecosystems. They report that the resistant bacteria and enzymes have been isolated from pigs and poultry in Germany (Escherichia coli and Salmonella infantis), from cattle and horses in France and Belgium (Acinetobacter spp.) and from pigs and poultry in China (Acinetobacter spp.).
According to EFSA control measures and regular monitoring are necessary. Restrictive use of carbapenems in humans is very important; the use in animals for food production is prohibited. Continued prohibition would be a simple and effective option, EFSA states. In addition a further decrease of antibiotics use in animal production would be effective, as the genes for the production of carbapenemase and other enzymes targeting antibiotics are mostly carried by plasmids. Those genetic structures can easily be transmitted between bacteria and co-resistance may be important for the spread of such resistance mechanisms.
Further along the supply chain hygienic measures are also strongly recommended, from cleaning and disinfection in industry to hand washing and thorough heating of meat by consumers. The heat kills the resistant bacteria and inactivates their plasmids and enzymes.