Last data update: Jun 11, 2024. (Total: 46992 publications since 2009)
Records 1-6 (of 6 Records) |
Query Trace: Lott TJ [original query] |
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Genotyping of Candida parapsilosis from three neonatal intensive care units (NICUs) using a panel of five multilocus microsatellite markers: broad genetic diversity and a cluster of related strains in one NICU.
Reiss E , Lasker BA , Lott TJ , Bendel CM , Kaufman DA , Hazen KC , Wade KC , McGowan KL , Lockhart SR . Infect Genet Evol 2012 12 (8) 1654-60 Candida parapsilosis (CP) (n=40) isolated from an unselected patient population in the neonatal intensive care units (NICUs) of 3 U.S. hospitals were collected over periods of 3.5-9 years. Two previously published microsatellite markers and three additional trinucleotide markers were used to produce multiplex genotypes, which revealed broad strain diversity among the NICU isolates with a combined index of discrimination (D)=0.997. A cluster of 8 related CP strains from 4 infants in a single NICU was observed. An extended collection of 24 CP isolates from the general population of that hospital showed that the cluster of NICU isolates was related to 3 isolates from general hospital patients. This microsatellite marker set is suitable to investigate clusters of colonizing and infecting strains of CP. |
Bloodstream and non-invasive isolates of Candida glabrata have similar population structures and fluconazole susceptibilities
Lott TJ , Frade JP , Lyon GM , Iqbal N , Lockhart SR . Med Mycol 2011 50 (2) 136-42 We have compared multilocus sequence typing (MLST) and fluconazole susceptibility profiles of Candida glabrata bloodstream isolates obtained during active, population-based surveillance to those obtained from non-sterile sites of individuals with no evidence of fungal disease (i.e., non-invasive isolates) in the same US city during an overlapping time period. In each of the two populations, different proportions of the same six major sequence types (STs) encompassed 82% of the isolates. One ST was more prevalent in the candidemia population and two other STs were more prevalent in the non-invasive population, but the overall allelic frequencies within the groups suggested little, if any, genotypic diversity between them. Fluconazole susceptibility profiles of isolates from the patients in the two groups were not significantly different and were not associated with a particular sequence type. Our results support the hypothesis that C. glabrata strains causing bloodstream infections are genetically indistinguishable from those normally residing in/on the host, suggesting that relative pathogenicity may be closely tied to commensalism. |
Multilocus sequence typing of sequential Candida albicans isolates from patients with persistent or recurrent fungemia
Da Matta DA , Melo AS , Guimaraes T , Frade JP , Lott TJ , Colombo AL . Med Mycol 2010 48 (5) 757-62 Multilocus sequence typing (MLST) is a useful tool to explore the phylogenetics and epidemiology of Candida albicans isolates recovered from cases of invasive candidiasis. The goal of this study was to determine whether the same or different strains were responsible for persistent or recurrent fungemia through the use of MLST and ABC typing on sequential C. albicans isolates from the same patient. We applied both typing methods to 21 C. albicans strains recovered from 8 patients with persistent or recurrent candidemia. The isolates were collected during a multicenter surveillance study in four public tertiary care hospitals in Brazil. Persistent candidemia was defined as two or more blood cultures positive for C. albicans on 2 or more separate days. Recurrent candidemia was defined as an episode of candidemia occurring at least 1 month after the apparent complete resolution of an infectious episode caused by Candida species. We observed that, except for one patient, all strains from the first and second samples of the same patient showed the same MLST diploid sequence type (DST), ABC type and susceptibility profile to antifungals. Three distinct strains, well discriminated by MLST, were found in the seven samples collected sequentially over 10 days from one patient. The strains from the first four samples were indistinguishable, the fifth and sixth were also indistinguishable but different from the first four and seventh samples. Significantly, the seventh strain was the only C. albicans clade 2 isolate found in our total collection involving 61 patients, although clade 2 is commonly found worldwide. To the best of our knowledge, this is the first study describing the recovery of three distinct C. albicans strains in the same patient with a persistent blood stream infection within a short period of time. |
Candidemia surveillance in Brazil: evidence for a boundary defining an abatement of Candida albicans group two strains
Da Matta DA , Melo AS , Colombo AL , Frade JP , Nucci M , Lott TJ . J Clin Microbiol 2010 48 (9) 3062-7 Prospective population surveillance has been conducted for candidemia in Brazil (5). In the present study, a total of 63 isolates from 61 patients, representing 11 medical centers from 9 geographic regions, were characterized by multi-locus sequence typing (MLST). A total of 48 unique profiles or diploid sequence types (DST) were observed, with 9 new sequence types (STs) and 32 new DSTs. There were no apparent correlations between center/region and DST patterns. Subtypes were compared to those in a known characterized reference set including a large database of strains obtained worldwide. Significantly, only one C. albicans Group 2 isolate was found in our collection, although isolates from this particular group are commonly found worldwide. These data, combined with information from other published studies, establish a statistically significant diminishment of Group 2 strains in Central and South America, including Mexico and portions of the Southwestern United States. |
A multicenter collaborative study for the standardization of Candida albicans genotyping using a polymorphic microsatellite marker
Garcia-Hermoso D , Maccallum DM , Lott TJ , Sampaio P , Buitrago Serna MJ , Grenouillet F , Klaassen CH , Bretagne S . J Clin Microbiol 2010 48 (7) 2578-81 Microsatellite-based genotyping for Candida albicans can give discrepant results between laboratories when expressed in fragment sizes since their determination depends on electrophoretic conditions. The inter-laboratory reproducibility was assessed in six laboratories provided with an allelic ladder. Despite variations in size determination, alleles were correctly assigned, making data transportable between laboratories. |
MLST analysis reveals both clonality and recombination in populations of Candida glabrata bloodstream isolates from US surveillance
Lott TJ , Frade JP , Lockhart SR . Eukaryot Cell 2010 9 (4) 619-25 The human commensal yeast Candida glabrata is becoming increasingly important as an agent of nosocomial bloodstream infection. However, relatively little is known concerning the genetics and population structure of this species. We have analyzed 230 incident bloodstream isolates from previous and current population based surveillance studies using multi-locus sequence typing (MLST). Our results show that in the US cities of Atlanta, GA, Baltimore, MD and San Francisco, CA during three time periods spanning 1992 to 2009, five populations of C. glabrata bloodstream isolates are defined by a relatively small number of sequence types. There is little genetic differentiation in the different C. glabrata populations. We also show that there has been a significant temporal shift in the prevalence of one major subtype in Atlanta. Our results support the concept that both recombination and clonality play a role in the population structure of this species. |
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