Microevolution of Candida albicans strains during catheter-related candidemia.
We examined microevolution in a series of Candida albicans strains isolated from patients with catheter-related candidemia. Sixty-one isolates (29 from blood, 18 from catheters, 10 from urine, and 4 from other sites) were obtained from 15 patients who were admitted to the same hospital over a 3-year period. Isolates were analyzed by using Southern hybridization with the C1 fragment of Ca3 as a probe (C1 fingerprinting) and pulsed-field gel electrophoresis (PFGE). PFGE typing consisted of electrophoretic karyotyping (EK) and restriction endonuclease analysis of genomic DNA (REAG) by using SfiI (REAG-S) and BssHII (REAG-B). When catheter isolates were compared with blood isolates from the same patient, catheter isolates from 5 of 14 patients (36%) exhibited minor band differences (microevolution) relative to blood isolates in either C1 fingerprinting (n = 4), REAG-S (n = 3), or REAG-B (n = 5) profiles, although they had identical EK patterns. However, the other sequential isolates from each patient, which had identical EK patterns, showed the same REAG and C1 fingerprinting patterns. Both fingerprinting methods revealed that two distinct genotypes were shared by isolates from seven patients in a neonatal intensive care unit, suggesting two nosocomial clusters. Except for two catheter isolates from the index patients of each cluster, no consecutive isolates collected from each of the two clusters showed any microevolution during the 2- or 7-month cluster periods. The findings suggest that in catheter-related candidemia, some C. albicans strains undergo microevolution during catheter colonization.
Shin
Jong Hee
JH
Department of Laboratory Medicine, Chonnam National University Medical School, 8 Hakdong Dongku, Gwangju 501-757, South Korea. shinjh@chonnam.ac.kr
Park
Mi-Ra
MR
Song
Jeong Won
JW
Shin
Dong Hyeon
DH
Jung
Sook-In
SI
Cho
Duck
D
Kee
Seung Jung
SJ
Shin
Myung Geun
MG
Suh
Soon Pal
SP
Ryang
Dong Wook
DW
D005075:Biological Evolution; D002176:Candida albicans / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D002177:Candidiasis / Q000453:epidemiology / Q000209:etiology*; D002408:Catheters, Indwelling / Q000009:adverse effects*; D003428:Cross Infection / Q000382:microbiology; D016172:DNA Fingerprinting; D016521:Electrophoresis, Gel, Pulsed-Field; D005838:Genotype; D006801:Humans