ADHESION AND COLONIZATION OF CANDIDA-KRUSEI ON HOST SURFACES

Candida krusei is an emerging pathogen, especially in immunocompromise d hosts. As the adherence of this organism both to host epithelial sur faces and to catheter and prosthetic surfaces appears to be important in the pathogenesis of superficial as well as systemic candidoses, the adhesion of 20 oral isolates of C. krusei and five oral isolates of C . albicans was compared with the following substrates: cultured (HeLa) epithelial cells, buccal epithelial cells (BEC) from healthy adults a nd bone marrow transplant patients, and acrylic (polymethylmethacrylat e) surfaces. Animal experiments in Sprague Dawley rats were also condu cted to evaluate the relative oral carriage rate of the two Candida sp p. C. krusei isolates adhered in far greater numbers to acrylic surfac es than to either of the cell surfaces. Significant intra-species diff erences in C. krusei adhesion for acrylic surfaces were noted between 74 (39%) of 190 pair comparisons in contrast to 18 (9.5%) of 190 with HeLa surfaces (p < 0.05). A positive correlation was also observed bet ween the adhesion of C. krusei isolates to HeLa cells and acrylic surf aces. Five isolates of C. albicans showed very low adherence to HeLa s urfaces when compared with BEC obtained from either healthy individual s or bone marrow transplant patients. The adherence of C. albicans to BEC from the healthy individuals was c. 12-fold greater than that of C . krusei, a figure similar to the relative murine oral carriage rate o f the two Candida spp. However, the adhesion of C. albicans to BEC fro m bone marrow transplant patients was three-fold less than to BEC of h ealthy individuals whilst C. krusei adhesion remained the same, reflec ting a possible selective colonisation process which may operate in th ese patient groups, possibly as a result of drug therapy. The current data, while confirming the inter- and intra-species differences in adh erence of Candida spp. to host surfaces, illustrate that adherence-rel ated factors may operate during colonisation of C. krusei on mucosal, catheter and prosthetic surfaces, in vivo in both health and disease.