Ciprofloxacin binding to GyrA causes global changes in the proteome of Pseudomonas aeruginosa.

Hannah Jedrey,Kathryn S Lilley,Martin Welch

doi:10.1093/femsle/fny134

Abstract

Ciprofloxacin is one of the most widely-used antibiotics, and has proven especially effective at controlling infections associated with the opportunistic human pathogen, Pseudomonas aeruginosa. In this work, we show that sub-inhibitory concentrations of ciprofloxacin induce discrete changes in the intracellular proteome. Central metabolism and cell envelope-associated functions are particularly affected. In spite of the low magnitude of the intracellular proteomic changes, we found that sub-lethal concentrations of ciprofloxacin had substantial effects on motility and exoprotein secretion. Crucially, the proteomic and phenotypic modulations that we observed were absolutely dependent upon the presence of wild-type GyrA; an isogenic strain of P. aeruginosa carrying a ciprofloxacin-insensitive form of GyrA (a T83→I mutant) did not display ciprofloxacin-dependent changes unless complemented with wild-type gyrA in trans. These results show that the diverse effects of sub-inhibitory ciprofloxacin on the cell are routed through its primary target in the cell, DNA gyrase.

Highlights

Pseudomonas aeruginosa is an opportunistic pathogen responsible for causing a variety of human disease states, especially among immunocompromised individuals
Our results suggest that sub-MICCIP has significant impacts on central metabolism and protein secretion, and these effects are largely dependent upon the presence of a CIP-sensitive gyrA allele
We show that the adaptive response to sub-MICCIP involves a small number of moderate (

Summary

Introduction

Pseudomonas aeruginosa is an opportunistic pathogen responsible for causing a variety of human disease states, especially among immunocompromised individuals. One of the most effective antibiotics used to treat P. aeruginosa infections is the second generation fluoroquinolone, ciprofloxacin (CIP) (Wise, Andrews and Edwards 1983). Introduced in 1987, CIP proved so effective at treating a wide range of bacterial infections that it rapidly joined the WHO list of medicines essential for basic healthcare. CIP has a broad spectrum of action with good tissue penetration, oral absorption and favourable phamacokinetics, making it ideal for the treatment of a wide range of infections. The presence of the cyclopropane moiety on the N atom of the heterocycle in CIP increases its activity (compared with first generation fluoroquinolones such as norfloxacin) against P. aeruginosa by a factor of four

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