Journal of Infectious Diseases & Therapy
Open Access

Abstract

Statement of the Problem: Pseudomonas aeruginosa is a Gram-negative ubiquitous microorganism found in various environmental niches as well as in human infections. It is innately resistant to many commercially available antibiotics and has acquired a wide array of resistance mechanisms, tremendously complicating the clinical handling of P. aeruginosa infections. Antibiotic resistance can be mediated by several molecular mechanisms, one of them being the efflux of antibiotics from the bacterium through efflux pumps. In P. aeruginosa, antibiotic efflux is mainly mediated by pumps belonging to the Resistance- Nodulation-Division family: MexAB-OprM, MexCD-OprJ, MexEF-OprN and MexXY-OprM. This work aimed to compare their expression in environmental and clinical strains of P. aeruginosa from Algeria and France either resistant or susceptible to fluoroquinolones to evaluate whether expression patterns would vary according to the sample origin and/or country. Material & Methods: Clinical strains were collected from Amiens and Lille hospitals for France and Saida hospital for Algeria. Environmental strains were mostly isolated from water samples. Susceptibility to ciprofloxacin was evaluated by E-test and the broth microdilution method with and without an efflux inhibitor. Efflux pumps expression was then measured through a qRTPCR experiment, using mexB, mexD, mexF and mexY as target genes. Findings: 149 clinical and 30 environmental P. aeruginosa strains were included. According to EUCAST breakpoints, 29.8% and 11.1% of French and Algerian clinical strains were resistant to ciprofloxacin, respectively. None of the environmental strains were resistant to ciprofloxacin. Analysis of qRT-PCR data showed that mexY expression was significantly increased in a majority of ciprofloxacin-resistant clinical strains while mexA was decreased. Conclusion & Significance: This study showed that ciprofloxacin-resistant strains were more common in clinical P. aeruginosa isolates than in environmental one. The design of efflux inhibitors targeting MexXY-OprM efflux pump could therefore be of use to restore the activity of known antibiotics.

Biography

Catherine Mullié has obtained her PhD in Microbiology and a PharmD at the University of Lille, France, in 1999 and Post-doc at the Faculté de Medicine in Amiens (Laboratoire d’Immunologie, INSERM-EMI 0351). She was appointed as Assistant Professor at the Faculté de Pharmacie in Amiens in 2000 and joined the LG-2A (Laboratoire de Glycochimie des Antimicrobiens et des Agroressources, UMR 7378 CNRS) in 2008. She has been a Member of the French Society for Microbiology since 2000. Her research is focused on the development of new antimicrobial and antimalarial drugs, with a special interest in efflux-mediated antibiotic resistance in Pseudomonas aeruginosa and Acinetobacter baumannii. She is currently the Head of a bilateral project funded by France and Algeria (Partenariat Hubert Curien Tassili) on this topic.