FIG. 5.
Expression of hph results in lethality among mice infected with Histoplasma capsulatum. Groups of mice were intranasally infected with 2 × 106 yeast cells of H. capsulatum strains UC16, expressing zeocin resistance; UC17, expressing hygromycin resistance; UC24 and UC25, expressing zeocin and hygromycin resistance; or UC18 and UC19, expressing zeocin resistance and a nonfunctional hygromycin phosphotransferase (n = 6 to 12 mice per strain). Survival curves demonstrate the loss of animals infected with hygromycin-resistant H. capsulatum between days 10 and 15.