Strain delineation and epidemiology of Candida (Clavispora) lusitaniae

Electrophoretic karyotype (EK) patterns, determined by using contour-clamped homogeneous pulsed-field electrophoresis, and isoenzyme (IZ) profiles were evaluated as methods for strain delineation among 35 isolates of Candida lusitaniae recovered from 15 patients. All isolates were identified to the species level by using conventional morphologic and physiologic criteria, and the identification was confirmed by gas-liquid chromatography analysis of the cellular fatty acids. The isolates were then typed without knowledge of the patient source. The IZ profiles showed all isolates to be closely related. Fifteen EK patterns were found; each pattern was restricted to isolates recovered from a single patient. In contrast, on the basis of heterogeneity in phosphatases, beta-glucosidases, esterases, and catalases, 10 IZ profiles were found; 4 were shared by isolates recovered from more than one patient. Multiple isolates from six patients were analyzed, and for each patient, a single EK- and IZ-defined type was found. The types of isolates obtained from two patients, after the emergence of resistance to amphotericin B, remained the same as the types of isolates obtained earlier. The data suggest that a patient becomes colonized by a single strain of C. lusitaniae which may disseminate to multiple sites, that the colonizing strain can persist during the patient's hospitalization, and that it may develop resistance to amphotericin B. Both EK patterns and IZ profiles can be used to delineate strains of C. lusitaniae, but the EK pattern provides more discriminatory power.