In vitro activities of 13 fluoroquinolones against Staphylococcus aureus isolates with characterized mutations in gyrA, gyrB, grlA, and norA and against wild-type isolates.
The in vitro activities of 13 fluoroquinolones (FQs) were tested against 90 Staphylococcus aureus clinical isolates: 30 wild type for gyrA, gyrB, grlA and norA and 60 with mutations in these genes. Clinafloxacin (CI-960), sparfloxacin, and grepafloxacin were the most active FQs against wild-type isolates (MICs at which 90% of isolates were inhibited, 0.06 to 0.1 microgram/ml). Mutations in grlA did not affect the MICs of newer FQs. grlA-gyrA double mutations led to higher MICs for all the FQs tested. Efflux mechanisms affected the newer FQs to a much lesser extent than the less recently developed FQs.
Muñoz Bellido
J L
JL
Departamento de Microbiología, Hospital Universitario de Salamanca, Spain.
Alonso Manzanares
M A
MA
Yagüe Guirao
G
G
Gutiérrez Zufiaurre
M N
MN
Toldos
M C
MC
Segovia Hernández
M
M
Garcia-Rodríguez
J A
JA
D000890:Anti-Infective Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D027081:DNA Gyrase; D027101:DNA Topoisomerase IV; D004250:DNA Topoisomerases, Type II / Q000235:genetics; D024841:Fluoroquinolones; D006801:Humans; D008826:Microbial Sensitivity Tests; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009154:Mutation; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics
D000890:Anti-Infective Agents; D001426:Bacterial Proteins; D027081:DNA Gyrase; D027101:DNA Topoisomerase IV; D004250:DNA Topoisomerases, Type II; D024841:Fluoroquinolones; D027425:ATP-Binding Cassette, Sub-Family C Proteins; C075040:NorA protein, Staphylococcus