Candida albicans strain maintenance, replacement, and microvariation demonstrated by multilocus sequence typing
Candida albicans strain maintenance, replacement, and microvariation demonstrated by multilocus sequence typing
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DOI：
10.1128/jcm.00934-06
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发表时间：
2006-10-01
影响因子：
9.4
通讯作者：
Gow, N. A. R.
中科院分区：
文献类型：
--
作者：
Odds, F. C.;Davidson, A. D.;Gow, N. A. R.
我们分型165白色念珠菌分离物从44个不同的来源，多位点序列分型（MLST）和ABC分型的rRNA基因，并确定其纯合性或杂合性在交配型样位点（MTL）。分离株代表来自个体来源的菌株对或较大的菌株集，这允许确定患者内的菌株多样性。重复序列数据的比较确定了将分离株视为MLST不可区分的再现性阈值。对于36个分离株集，MLST和ABC分型显示来自不同地点或来自同一地点在不同时间从每个患者分离的分离株之间不可区分或高度相关的菌株类型。该观察结果包括11组，其中至少有1株分离株来自同一患者的血培养和非无菌部位。对于1例患者，菌株替换以来自不同入院的两组分离株的形式得到证实，其中每组内的菌株类型几乎相同，但两组的MLST和ABC分型均不同。MLST因此证实了C.白色念珠菌菌株携带。微变异，表现为MLST类型之间的小差异，导致在大多数情况下，在一个或多个测序位点的杂合性丢失。在表现出主要菌株类型差异的分离株组中，可以排除一些分离株，因为它们可能是储存期间处理错误的例子。然而，对于少数分离株，紧簇MLST型的ABC型的间歇性差异和MTL纯合性的间歇性出现使我们提出一些C。白色念珠菌分离株或在尚未确定的条件下的所有分离株通过诸如重组、基因转换或染色体倍性改变的机制保持高水平的遗传多样性。
We typed 165 Candida albicans isolates from 44 different sources by multilocus sequence typing (MLST) and ABC typing of rRNA genes and determined their homozygosity or heterozygosity at the mating-type-like locus (MTL). The isolates represented pairs or larger sets from individual sources, which allowed the determination of strain diversity within patients. A comparison of replicate sequence data determined a reproducibility threshold for regarding isolates as MLST indistinguishable. For 36 isolate sets, MLST and ABC typing showed indistinguishable or highly related strain types among isolates from different sites or from the same site at different times from each patient. This observation included 11 sets with at least one isolate from a blood culture and a nonsterile site from the same patient. For one patient, strain replacement was evidenced in the form of two sets of isolates from different hospital admissions where the strain types within each set were nearly identical but where the two sets differed both by MLST and ABC typing. MLST therefore confirms the existing view of C. albicans strain carriage. Microvariation, evidenced as small differences between MLST types, resulted in most instances from a loss of heterozygosity at one or more of the sequenced loci. Among isolate sets that showed major strain type differences, some isolates could be excluded as likely examples of handling errors during storage. However, for a minority of isolates, intermittent differences in ABC type for tightly clustered MLST types and intermittent appearances of MTL homozygosity lead us to propose that some C. albicans isolates, or all isolates under yet-to-be-determined conditions, maintain a high level of genetic diversity by mechanisms such as recombination, gene conversion, or chromosomal ploidy change.