Electrophoretic karyotype analysis of sequential Candida parapsilosis isolates from patients with persistent or recurrent fungemia

We assessed the genetic relatedness of sequential isolates of Candida parap silosis during persistent or recurrent fungemia and the effect of central v enous catheter (CVC) removal. Serial isolates of C. parapsilosis were obtai ned from 17 patients with persistent or recurrent fungemia over periods of up to 5 months. Forty-eight C, parapsilosis isolates from the blood of 17 p atients were analyzed by electrophoretic karyotyping (EK) with pulsed-field gel electrophoresis (PFGE), revealing 25 different karyotypes. The strains sequentially isolated from each of seven patients whose fungemia resolved following CVC removal had the same karyotype, Two patients with fungemia th at cleared without CVC removal each had two sequential isolates with differ ent karyotypes, In six (75%) of the eight patients whose fungemia was recur rent even after CVC removal, the karyotypes of the pre- and post-CVC remova l isolates were different, implying the emergence of a new strain. Overall, the sequential strains from each patient had identical karyotypes in 53% ( 9 of 17) of the patients and two different karyotypes in 47% (8 of 17), Thi s study shows that EK with PFGE is useful for investigating persistent or r ecurrent fungemia due to C, parapsilosis and that recurrent fungemia due to C, parapsilosis is more likely caused by reinfection with a second strain.