Question

Describe 3 features of Pseudomonas aeruginosa that complicate treatment of infected vascular grafts.

Answer 1

Ans. -

(1) Management of prosthetic vascular graft infections caused by Pseudomonas aeruginosa can be a significant challenge to clinicians. Bacteriophage OMKO1 binding to efflux pump proteins in Pseudomonas aeruginosa was consistent with an evolutionary trade-off: wildtype bacteria were killed by phage whereas evolution of phage-resistance led to increased antibiotic sensitivity. The infections by Pseudomonas aeruginosa often do not resolve with antibiotic therapy alone due to antibiotic resistance/tolerance by bacteria, poor ability of antibiotics to permeate/reduce biofilms and/or other factors.

(2) A common source of PVGIs is Pseudomonas aeruginosa, a ubiquitous Gram-negative, rod-shaped bacterium prevalent in natural and artificial environments and listed as an increasingly antibiotic resistant priority pathogen. Adaptation to myriad habitats has allowed Pseudomonas aeruginosa to persist in many human-associated environments, most notably in hospitals, where it is increasingly associated with nosocomial infections. Further complicating the problem of Pseudomonas aeruginosa infections is their ability to form biofilms. Biofilm-mediated infections are notoriously difficult to manage, due to their generally greater resistance to chemical antimicrobials and formation following sub-lethal concentrations of antibiotics.

(3) Detection of Pseudomonas aeruginosa colonisation is normally achieved by culture of wound swabbing on to artificial media. Typical isolation media for wound infections include blood agar and chocolate agar as well as selective agars such as Mac- Conkey agar and cetrimide-based media. Pseudomonas aeruginosa commonly inhabits soil, water, and vegetation. It is found in the skin of some healthy persons and has been isolated from the throat and stool of nonhospitalized patients.