Advertisement
Journal Home
Search for

Volume 45, Issue 1, Pages 63-67 (January 2003)


View previous. 2 of 12 View next.

Molecular characterization of fluoroquinolone resistant Streptococcus pneumoniae clinical isolates obtained from across Canada

George G. ZhanelabcCorresponding Author Informationemail address, Andrew Walktya, Kim Nicholac, Heather Smitha, Ayman Noreddina, Daryl J. Hobanac

Received 17 July 2002; accepted 9 September 2002.

Abstract 

There is little published data detailing fluoroquinolone resistance in clinical isolates of S. pneumoniae. The purpose of this study was to characterize the resistance mechanisms of 34 fluoroquinolone-resistant S. pneumoniae clinical isolates obtained from medical centers in 8 of 10 Canadian provinces between 1997 and 2000. The quinolone resistance determining regions of gyrA, parC, and parE from the isolates were sequenced. The isolates were evaluated for reserpine-sensitive efflux of ciprofloxacin and the new fluoroquinolones: gatifloxacin, gemifloxacin, levofloxacin and moxifloxacin. The isolates were typed using pulsed field gel electrophoresis. The majority of the isolates were genetically unrelated. Lower level fluoroquinolone resistance (ciprofloxacin MIC 4-8μg/ml) was associated with amino acid substitutions in ParC, while higher level resistance (ciprofloxacin MIC ≥16μg/ml) was associated with amino acid substitutions in both ParC and GyrA. ParE substitutions were not associated with clinical resistance. Twelve of 34 (35%) isolates demonstrated reserpine-sensitive efflux of ciprofloxacin. Efflux alone conferred low level ciprofloxacin resistance in 3 isolates. Significant reserpine-sensitive efflux of the new fluoroquinolones was not observed.

a Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada

b Department of Medicine, Health Sciences Centre, Winnipeg, Manitoba, Canada

c Clinical Microbiology Health Sciences Centre, Winnipeg, Manitoba, Canada

Corresponding Author InformationCorresponding author. Tel.:+(204) 787-4902; fax: +(204) 787-4699.

PII: S0732-8893(02)00498-4

doi:10.1016/S0732-8893(02)00498-4


View previous. 2 of 12 View next.

Advertisement