Caracterización epidemiológica de Pseudomonas sp provenientes del hospital de tercer nivel “Dr. Ignacio Morones Prieto”

Abstract

Pseudomonas aeruginosa is an opportunistic pathogen in HAIs with two facets: the most studied is the high rate of antimicrobial resistance, and the less explored is the long list of virulence factors it possesses. /is study aimed to characterize the virulence genes carried by strains as well as the pro6le of cytokines related to in7ammation, according to the resistance pro6le presented. /is study aims to identify the virulence factors associated with MDR strains, particularly those resistant to carbapenems, and assess whether there is a cytokine pro6le that correlates with these characteristics. As methodology species were identi6ed by classical microbiological techniques and con6rmed by molecular biology, resistance levels were determined by the minimum inhibitory concentration and identi6cation of MDR strains. Virulence factor genotyping was performed using PCR. In addition, bio6lm production was assessed using crystal violet staining. Finally, the strains were cocultured with PBMC, and cell survival and the cytokines IL-1β, IL-6, IL-10, IL-8, and TNF-α were quanti6ed using 7ow cytometry. Bacteremia and nosocomial pneumonia in adults are the most frequent types of infection. In the toxigenic aspect, genes corresponding to the type III secretion system were present in at least 50% of cases. In addition, PBMC exposed to strains of four di@erent categories according to their resistance and toxicity showed a di@erential pattern of cytokine expression, a decrease in IL-10, IL-6, and IL-8, and an over-secretion of IL-1b. In conclusion, the virulence genes showed a di@erentiated appearance for the two most aggressive exotoxins of T3SS (exoU and exoS) in multidrug-resistant strains. Moreover, the cytokine pro6le displays a low expression of cytokines with anti-in7ammatory and proin7ammatory e@ects in strains carrying the exoU gene.