title: Bacteremia due to viridans group Streptococci with diminished susceptibility to Levofloxacin among neutropenic patients receiving levofloxacin prophylaxis.
abstract: Despite the use of levofloxacin prophylaxis during the neutropenic period after autologous peripheral blood stem cell transplantation, viridans group (VG) streptococcal bacteremia developed in 6 (16.2%) of 37 patients who underwent transplantation between 1 January and 25 February 2001 at the Mayo Clinic in Rochester, Minnesota. All 6 patients presented with fever and mucositis after a mean of 4.5 days of neutropenia, and 3 developed septic shock. All 6 VG streptococcal isolates from these patients exhibited distinct patterns on pulsed-field gel electrophoresis. All isolates had diminished susceptibility to levofloxacin, 5 to gatifloxacin, and 4 to moxifloxacin. Quinolone resistance was associated with mutations in the quinolone resistance-determining region of GyrA and (for 1 isolate) of ParC. The use of levofloxacin may select VG streptococci with diminished susceptibility to levofloxacin and other quinolones with enhanced activity against gram-positive organisms and, therefore, may not be optimal for preventing VG streptococcal bacteremia in neutropenic patients.
authors.affiliation: Division of Infectious Diseases, Mayo Clinic, Rochester, MN, 55905, USA.
authors.forename: Raymund R
authors.initials: RR
authors.lastname: Razonable
authors.forename: Mark R
authors.initials: MR
authors.lastname: Litzow
authors.forename: Yasmin
authors.initials: Y
authors.lastname: Khaliq
authors.forename: Kerryl E
authors.initials: KE
authors.lastname: Piper
authors.forename: Mark S
authors.initials: MS
authors.lastname: Rouse
authors.forename: Robin
authors.initials: R
authors.lastname: Patel
mesh_terms: D000328:Adult; D000368:Aged; D000890:Anti-Infective Agents / Q000627:therapeutic use*; D016470:Bacteremia / Q000382:microbiology*; D018890:Chemoprevention / Q000009:adverse effects; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D064704:Levofloxacin; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009503:Neutropenia / Q000517:prevention & control*; D015242:Ofloxacin / Q000009:adverse effects / Q000627:therapeutic use*; D013291:Streptococcus / Q000187:drug effects
chemical_list: D000890:Anti-Infective Agents; D064704:Levofloxacin; D015242:Ofloxacin