The influence of heteroresistance, growth and antibiotic selection in shaping the invasion dynamics of colistin resistant Pseudomonas aeruginosa.

Heteroresistance and growth characteristics of Pseudomonas aeruginosa influence invasion success, with resistant strains gaining advantage at 2-4xMIC of clinical isolates.

• Why it matters: Understanding how heteroresistance affects resistant strain invasion is crucial for developing effective treatment strategies against bacterial infections, yet this relationship remains poorly understood.
• What they did: The study quantified invasion dynamics of colistin-resistant P. aeruginosa across a colistin gradient during co-culture with susceptible isolates exhibiting varying heteroresistance levels, analyzing the impact of these factors.
• The result: Results show that in antibiotic-free conditions, faster-growing isolates exclude resistant invaders, while high heteroresistance isolates do not; increasing colistin shifts the advantage to the resistant strain, highlighting the roles of heteroresistance and growth in invasion dynamics.