Fosfomycin and rifampin disk diffusion tests for detection of Escherichia coli mutator strains.
A simple method, using commercial disks to detect Escherichia coli mutator strains, is proposed. The breakpoint for detecting strains with a mutation frequency >/=5 x 10(-7) was established at >/=70 and >/=20 colonies in the inhibition zone of fosfomycin and rifampin disks, respectively, after seeding 100 microl of an overnight culture. Strains with <30 and <10 colonies in fosfomycin and rifampin inhibition zones are presumptively non-mutators.
Galán
Juan-Carlos
JC
Servicio de Microbiología, Hospital Universitario Ramón y Cajal, Ctra. de Colmenar, Km 9,1, 28034 Madrid, Spain. jgalanm.hrc@salud.madrid.org
Tato
Marta
M
Baquero
María-Rosario
MR
Turrientes
Carmen
C
Baquero
Fernando
F
Martinez
José-Luis
JL
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D003470:Culture Media; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D005578:Fosfomycin / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D009154:Mutation / Q000235:genetics*; D012293:Rifampin / Q000494:pharmacology*; D012680:Sensitivity and Specificity
D000900:Anti-Bacterial Agents; D003470:Culture Media; D005578:Fosfomycin; D012293:Rifampin