Impact of multidrug resistance on the virulence and fitness of Pseudomonas aeruginosa: a microbiological and clinical perspective.

Pseudomonas aeruginosa is one of the most common nosocomial pathogens and part of the top emergent species associated with antimicrobial resistance that has become one of the greatest threat to public health in the twenty-first century. This bacterium is provided with a wide set of virulence factors that contribute to pathogenesis in acute and chronic infections. This review aims to summarize the impact of multidrug resistance on the virulence and fitness of P.

Risk factors and clinical impact of multidrug resistance in healthcare-associated bacteraemic urinary tract infections: a post-hoc analysis of a multicentre prospective cohort in Spain.

Background: The global burden associated with antimicrobial resistance is of increasing concern.

Aim: To evaluate risk factors associated with multidrug-resistant (MDR) infection and its clinical impact in a cohort of patients with healthcare-associated bacteraemic urinary tract infections (BUTIs).

Methods: This was a prospective, multicentre, post-hoc analysis of patients with healthcare-associated-BUTI (ITUBRAS-2).

Evolution repeats itself in replicate long-term studies in the wild.

The extent to which evolution is repeatable remains debated. Here, we study changes over time in the frequency of cryptic color-pattern morphs in 10 replicate long-term field studies of a stick insect, each spanning at least a decade (across 30 years of total data). We find predictable "up-and-down" fluctuations in stripe frequency in all populations, representing repeatable evolutionary dynamics based on standing genetic variation.

Transferable AmpCs in : interplay with peptidoglycan recycling, mechanisms of hyperproduction, and virulence implications.

Chromosomal and transferable AmpC β-lactamases represent top resistance mechanisms in different gram-negatives, but knowledge regarding the latter, mostly concerning regulation and virulence-related implications, is far from being complete. To fill this gap, we used (KP) and two different plasmid-encoded AmpCs [DHA-1 (AmpR regulator linked, inducible) and CMY-2 (constitutive)] as models to perform a study in which we show that blockade of peptidoglycan recycling through AmpG permease inactivation abolished DHA-1 inducibility but did not affect CMY-2 production and neither did it alter KP pathogenic behavior. Moreover, whereas regular production of both AmpC-type enzymes did not attenuate KP virulence, when DHA-1 was expressed in an -defective mutant, killing was significantly (but not drastically) attenuated.