Multiple antibiotic resistance index, fitness and virulence potential in respiratory Pseudomonas aeruginosa from Jamaica.

Multiple antibiotic resistance index, fitness and virulence potential in respiratory Pseudomonas aeruginosa from Jamaica. J Med Microbiol. 2016 Feb 9; Authors: Davis R, Brown PD Abstract Respiratory infections are common causes of morbidity and mortality worldwide. We sought to assess the multiple antibiotic resistance (MAR) index, fitness, and virulence potential in Pseudomonas aeruginosa from patients with lower respiratory tract infections. Isolates were assessed for antimicrobial susceptibility, in vitro competitive ļ¬tness, pigment, elastase and rhamnolipid production. Oxidative stress tolerance was determined on both planktonic and biofilm cells and virulence potential was tested in a plant model. Mean MAR index for isolates was 0.34 (range, 0.17 - 0.50). While isolates exhibited good biofilm formation in the presence of ciprofloxacin, there was no significant difference in biofilm production over the concentration range assessed. Several drug-resistant strains were out-competed by a sensitive strain in the presence of antibiotic.H2O2 exerted a greater oxidative stress than tert-butyl hydroperoxide, and as expected, biofilms were more resistant than planktonic cells. While most (81%) isolates were pigmented there was no significant difference between pigmented and non-pigmented isolates when elastolytic activity was compared (p>0.05). More than half of the isolates produced the quorum sensing mediator, rhamnolipid, and infe...
Source: Journal of Medical Microbiology - Category: Microbiology Authors: Tags: J Med Microbiol Source Type: research