Resistencia antibiótica en Acinetobacter spp. y Enterobacter cloacae complexepidemiología, mecanismos y tratamiento

Abstract

Antibiotic resistance, involving Acinetobacter baumannii and the Enterobacter cloacae complex (ECC) as pivotal microorganisms, significantly contributes to global morbimortality. Studying these populations is crucial for developing effective strategies to lessen the impact of the resulting infections on public health. In this Doctoral Thesis two multicentric national collections of clinical strains, one comprising Acinetobacter spp. and the other ECC isolates, are examined to discern their epidemiology, resistance patterns and mechanisms, and to ultimately explore the activity of new therapeutic alternatives. Cefiderocol emerges as the most potent antibiotic against A. baumannii, followed by colistin, despite its notable decrease in efficacy over the past decade. Attention is drawn to the issue of ST2, characterized by numerous XDR isolates and a notable representation of OXA-23, signaling a paradigm shift in carbapenem-resistant A. baumannii epidemiology in Spain. This resistance, largely mediated by class D carbapenemases, is mitigated by the LN-1-255 inhibitor, restoring the potential of compounds like imipenem or sulbactam. On another note, in this Thesis, plasmid-mediated dissemination of the carbapenemase OXA-24/40 among isolates of Acinetobacter nonbaumannii belonging to the collection is characterized for the first time, highlighting its international spread. Concerning ECC, the association of VIM-1 with diminished susceptibility to cefiderocol is demonstrated, addressing microbiological, biochemical, and molecular factors. Furthermore, emphasis is placed on the influence of additional factors restricting the activity of this latest generation cephalosporin in ECC.