Type IV PilD mutant stimulates the formation of persister cells in Pseudomonas aeruginosa.

Abstract

Background: Pseudomonas aeruginosa clinical isolates that lack motility do not express type IV pilin, yet the biological roles of this absence in the infection process remain poorly understood.

Objectives: We asked whether the absence of motility in these bacteria is associated with increased antibiotic persistence.

Methods: In this study, we analysed type IV PilD protein sequences in the database and conducted antibiotic-tolerant persister cell assays.

Results: We found that PilD variants were common in P. aeruginosa clinical isolates. Our results revealed that inactivation of PilD resulted in a significantly higher level of surviving persister cells following ciprofloxacin treatment. This PilD-mediated persistence did not involve previously described mechanisms, such as phenazine pyocyanin, biofilm or stringent response.

Conclusions: Our findings connect the non-motility of clinical P. aeruginosa isolates with the survival of persister cells, highlighting the clinical significance for the development of strategies to eradicate P. aeruginosa infections.