Among the Candida species causing bloodstream infections, Candida parapsilosis is one of the most frequently isolated. The objective of the present work was the identification of new microsatellite loci able to distinguish among C. parapsilosis isolates. DNA sequences with trinucleotide repeats were selected from the C. parapsilosis genome database. PCR primer sets flanking the microsatellite repeats were designed and tested with 20 independent isolates. On the basis of the amplification efficiency, specificity, and observed polymorphism, four of the sequences were selected for strain typing. Two hundred thirty-three independent C. parapsilosis sensu stricto isolates were genotyped by using these markers. The polymorphic loci exhibited from 20 to 42 alleles and 39 to 92 genotypes. In a multiplex analysis, 192 genotypes were obtained and the combined discriminatory power of the four microsatellites was 0.99. Reproducibility was demonstrated by submission of subcultures of 4 isolates each, in triplicate, interspersed with unique numbers among a group of 30 isolates for blind testing. Comparison of the genotypes obtained by microsatellite analysis and those obtained by randomly amplified polymorphic DNA analysis, restriction fragment length polymorphism analysis, and internal transcribed sequence grouping was performed and showed that the microsatellite method could distinguish individual isolates; none of the other methods could do that. Related species, C. orthopsilosis and C. metapsilosis, were not confused with C. parapsilosis sensu stricto. These new microsatellites are a valuable tool for use for the differentiation of C. parapsilosis sensu stricto strains, vital in epidemiology to answer questions of strain relatedness and determine pathways of transmission.
Whilst the potential impact on beach users from microorganisms in water has received considerable attention, there has been relatively little investigation into microbial contaminants in sand. 33 beaches across Portugal were analyzed during a five year period (2006)(2007)(2008)(2009)(2010) to determine the presence of yeasts, pathogenic fungi, dermatophytes, total coliforms, E. coli and intestinal enterococci in sand.Our results showed that 60.4% of the samples were positive for fungi and that 25.2% were positive for the bacterial parameters. The most frequent fungal species found were Candida sp.and Aspergillus sp., whereas intestinal enterococci were the most frequently isolated bacteria.Positive associations were detected among analyzed parameters and country-regions but none among those parameters and sampling period.Regarding threshold values, we propose 15 cfu/g for yeasts, 17 cfu/g for potential pathogenic fungi, 8 cfu/g for dermatophytes. 84 cfu/g for coliforms, 250 cfu/g for E. coli, and 100 cfu/g for intestinal enterococciHighlights:x 60.4% of the analyzed marine beach sand samples were positive for the studied fungi x Candida sp. and Aspergillus sp. were the most frequent fungal species found x 25.2% of the analyzed marine beach sand samples were positive to the studied bacteria
Candida parapsilosis emerged as an important opportunistic pathogen, causing candidaemia worldwide. Nosocomial outbreaks triggered by this species have been frequently described, particularly in cancer patients. For a better understanding of its epidemiology, several typing methods are used and microsatellite analysis has been reported as highly discriminant. The main objective of this work was to study C. parapsilosis isolates by application of microsatellite genotyping to distinguish epidemiologically related strains, compare clinical and environmental isolates and determine possible routes of dispersion of the isolates in the hospital setting. A total of 129 C. parapsilosis isolates from different origins, including hospital environment and hands of healthcare workers, were genotyped using four microsatellite markers. The isolates were recovered from different health institutions. Analysis of C. parapsilosis isolates from hospital environment showed great genotypic diversity; however, the same or very similar genotypes were also found. The same multilocus genotype was shared by isolates recovered from the hand of a healthcare worker, from the hospital environment and from patients of the same healthcare institution, suggesting that these could be possible routes of transmission and that infections due to C. parapsilosis may be mainly related with exogenous transmission to the patient. Examination of sequential isolates from the same patients showed that colonizing and bloodstream isolates had the same multilocus genotype in the majority of cases. We demonstrate that this typing method is able to distinguish clonal clusters from genetically unrelated genotypes and can be a valuable tool to support epidemiologic investigations in the hospital setting.
This study presents data on the incidence of candidemia in a Portuguese oncology hospital during a 6-year period. The species distribution and their antifungal susceptibility, as well as the clinical outcomes associated with candidemia were evaluated. A total of 119 episodes were reported, with the majority occurring among patients older than 56 years. The most common underlying medical conditions were solid tumors (64.5%) and hematological disease (28.2%). The most frequent species found was Candida albicans (48.7%), followed by C. parapsilosis (20.2%), C. tropicalis (8.4%), C. krusei (6.7%) and C. glabrata (5.0%), but Saccharomyces cerevisiae and Rhodotorula mucilaginosa were also isolated. Candida albicans was more frequently associated with solid tumors of the gastrointestinal and genitourinary tracts and breast (P=0.005), while non-C. albicans Candida species were most frequently recovered from hematological patients (P=0.007). The mortality rate associated with candidemia was 31.9% (P=0.016). All C. albicans and C. parapsilosis isolates were susceptible to fluconazole, voriconazole and itraconazole. Resistance to caspofungin was only observed in C. albicans and in the R. mucilaginosa isolates. Posaconazole was active against all C. parapsilosis isolates tested but resistant strains were found among C. albicans (4.9%), C. tropicalis (12.5%), C. krusei (25%) and C. glabrata (50%). This study provides useful information regarding the local epidemiology of candidemia in cancer patients.
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