Send to

Choose Destination
Microb Drug Resist. 2000 Summer;6(2):111-7.

Evidence of an efflux pump in Serratia marcescens.

Author information

Microbiology Unit, University of Barcelona, Spain.


Spontaneous mutants resistant to fluoroquinolones were obtained by exposing Serratia marcescens NIMA (wild-type strain) to increasing concentrations of ciprofloxacin both in liquid and on solid media. Frequencies of mutation ranged from 10(-7) to 10(-9). Active expulsion of antibiotic was explored as a possible mechanism of resistance in mutants as well as changes in topoisomerase target genes. The role of extrusion mechanisms in determining the emergence of multidrug-resistant bacteria was also examined. Mutants resistant to high concentrations of fluoroquinolones had a single mutation in their gyrA QRDR sequences, whereas the moderate resistance in the rest of mutants was due to extrusion of the drug.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Atypon
Loading ...
Support Center