Schmid Jan, Herd Scott, Hunter Paul R, Cannon Richard D, Yasin M Salleh M, Samad Shamin, Carr Mary, Parr Dinah, McKinney Wendy, Schousboe Mona, Harris Ben, Ikram Rosemary, Harris Mike, Restrepo Angela, Hoyos Guillermo, Singh Kumar P
Institute of Molecular BioSciences, Massey University, Palmerston North, New Zealand1.
Public Health Laboratory, Countess of Chester Health Park, Chester , UK2.
Microbiology (Reading). 1999 Sep;145 ( Pt 9):2405-2413. doi: 10.1099/00221287-145-9-2405.
Epidemiological studies, using the probe Ca3, have shown that in a given patient population a single cluster of genetically related Candida albicans isolates usually predominates. The authors have investigated whether these local clusters are part of a single group, geographically widespread and highly prevalent as an aetiological agent of various types of candidiasis. An unrooted neighbour-joining tree of 266 infection-causing C. albicans isolates (each from a different individual) from 12 geographical regions in 6 countries was created, based on genetic distances generated by Ca3 fingerprinting. Thirty-seven per cent of all isolates formed a single genetically homogeneous cluster (cluster A). The remainder of isolates were genetically diverse. Using the maximum branch length within cluster A as a cut-off, they could be divided into 37 groups, whose prevalence ranged between 0.3% and 9%. Strains from cluster A were highly prevalent in all but one geographical region, with a mean prevalence across all regions of 41%. When isolates were separated into groups based on patient characteristics or type of infection, strains from cluster A had a prevalence exceeding 27% in each group, and their mean prevalence was 43% across all patient characteristics. These data provide evidence that cluster A constitutes a general-purpose genotype, which is geographically widespread and acts as a predominant aetiological agent of all forms of candidiasis in all categories of patients surveyed.
