28 Apr 2009
Both usage and resistance shows increasing trends. Therapeutic usage of antibiotics in food animals in The Netherlands has almost doubled in the past decade. Resistance levels in animal bacteria show a simultaneous tendency to increase, both for individual drugs and multi-drug resistance.
Likely determinants for the increase in usage are the ban and fading out of the growth promoters and the up scaling of farm sizes. The quality of animal feed is under stress because of high prices on the global market and the ban of animal protein in feed, which may affect the digestibility in the GI-tract which is compensated by oral antibiotics. The continuous increase in antibiotic usage is striking because currently in The Netherlands there is an intense debate about the negative effects and public health risks of antibiotic usage in intensive animal husbandry.
Next to the frequent occurrence of MRSA in Dutch food-animals, of particular concern is the rapid increase in the occurrence in Extended Spectrum Beta-Lactamase (ESBL) producing organisms in predominantly poultry and poultry meat products. This increase is both observed to occur frequently in the commensal GI-tract flora of broiler chickens, in Salmonella serovars from broilers and to a lesser extend in Salmonella from humans. Compared to the animal derived MRSA the risks of acquiring ESBLs by humans are different. MRSA is mainly transmitted by direct contact, while for the ESBLs food borne transmission is likely to contribute to the dissemination, since the genes are located on mobile genetic element and therefore transferable within and between bacterial species. Projects to study the genetic relation of these ESBLs in animals with ESBLs in human isolates have been initiated.
For more information, see the MARAN report 2007
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