Estudi de les (beta)-lactamases plasmídiques d'espectre ampliat, cefamicinases i carbapenemases en diferents ecosistemes. Anàlisi del seu entorn genètic

by Mesa González, Raúl Jesús

This thesis describes the prevalence of strains carrying extended spectrum betalactamase (ESBL), plasmid-mediated AmpC and carbapenemase. There are the main mechanism of betalactam resistance, not only in clinic environment [clinical samples and patients attending the emergency room (faecal carriers)] also in others environments such as the floor of animal farms (poultry, pig and rabbit), the urban sewage, food, and human faecal carriers in the context of food-borne disease outbreaks. We have characterized these enzymes to know the frequency of each type of betalactamase: TEM, SHV and CTX-M type as ESBL, CMY, DHA and ACC as plasmid-mediated AmpC, or VIM, IMP and others as carbapenemase. The works conclusion shows that these enzymes can be found in all environments evaluated. Then the selection of strains carrying this kind of enzymes is due not only to clinic environments otherwise to all human environments. In the other hand, we have described two new betalactamase, CTX-M-14b and CTX-M-51, both deriving from CTX-M-9. The finding of strains carrying these enzymes in all the environments is of great concerning. We need not to select these strains, and to know what are the mechanisms of expansion of these enzymes. The epidemiologic study of the resistance mechanism is of great interest, not only in hospitals also in veterinarian environment, because knowing the prevalence and the type of enzymes, we can design specific antibiotic policy.