Morphotypic and genotypic characterization of sequential Candida parapsilosis isolates from an outbreak in a pediatric intensive care unit

Microsatellite markers for genotyping of Kodamaea ohmeri: Demonstrating outbreaks based on a multicenter surveillance study in China

Kodamaea ohmeri, an emerging human pathogen, caused both sporadic and nosocomial infections among immunocompromised people with high mortality. However, there is limited research on the molecular epidemiology of K. ohmeri. A total of fifty microsatellite loci were designed based on K. ohmeri type strain NRRL Y-1932 and three loci were finally selected for microsatellite analysis. Non-duplicated K. ohmeri isolates and strains of other species were collected across China as a part of CHIF-NET program for sensitivity and specificity verification. Antifungal susceptibility was determined using Sensititre YeastOne TM YO10. The three loci (P10, P11 and P26), with a cumulative discriminatory power of 0.98, exhibited a prospective specificity and reproducibility in the PCR of 92 K. ohmeri strains from different hospitals. A total of 54 microsatellite types (MT) were identified and most of them distributed sporadically. However, six strains of MT12 clustered in HZ hospital and were isolated in the same department within two months, indicating a potential outbreak. Of seven isolates exhibited MIC values of >8 mg/L for fluconazole, three isolates from LR hospital shared the same genotype of MT44. Herein, we established a set of microsatellite loci for K. ohmeri, as a rapid and specific tool for genotyping K. ohmeri, and identified several potential clusters. This study will help us better understand the molecular epidemiology of the emerging pathogen K. ohmeri.

Outbreaks of Fungal Infections in Hospitals: Epidemiology, Detection, and Management

Nosocomial clusters of fungal infections, whilst uncommon, cannot be predicted and are associated with significant morbidity and mortality. Here, we review reports of nosocomial outbreaks of invasive fungal disease to glean insight into their epidemiology, risks for infection, methods employed in outbreak detection including genomic testing to confirm the outbreak, and approaches to clinical and infection control management. Both yeasts and filamentous fungi cause outbreaks, with each having general and specific risks. The early detection and confirmation of the outbreak are essential for diagnosis, treatment of affected patients, and termination of the outbreak. Environmental sampling, including the air in mould outbreaks, for the pathogen may be indicated. The genetic analysis of epidemiologically linked isolates is strongly recommended through a sufficiently discriminatory approach such as whole genome sequencing or a method that is acceptably discriminatory for that pathogen. An analysis of both linked isolates and epidemiologically unrelated strains is required to enable genetic similarity comparisons. The management of the outbreak encompasses input from a multi-disciplinary team with epidemiological investigation and infection control measures, including screening for additional cases, patient cohorting, and strict hygiene and cleaning procedures. Automated methods for fungal infection surveillance would greatly aid earlier outbreak detection and should be a focus of research.

Candidemia in Children: A 16-year Longitudinal Epidemiologic Study

BACKGROUND

Candida species are the most common cause of systemic fungal infections in children. Risk factors for candidemia vary in different patient populations, posing challenges for clinical prediction of infection. We describe the epidemiology and clinical disease of candidemia in children admitted to a tertiary pediatric hospital.

METHODS

Retrospective audit of children ≤18 years of age with candidemia at a tertiary pediatric hospital over a 16-year period.

RESULTS

There were 139 episodes of candidemia in 124 children. A central venous catheter was present in 94% of episodes, prior antibiotic exposure in 86% and parenteral nutrition in 43%. During the study period, the proportion of candidemia due to non-albicans Candida spp. increased primarily due to a rise in C. krusei. Colonization with Candida spp. in the 30 days before developing candidemia was identified in 40% of episodes and the species was concordant in 60%. Infection at other sites was rare, including pulmonary dissemination (9/38, 24%), renal fungal disease (9/114, 8%), fungal endophthalmitis (8/102, 8%) and hepatosplenic nodules (5/92, 5%). Overall, 8/127 (6%) isolates were fluconazole-resistant (7 C. krusei and 1 C. glabrata) and 7/127 (6%) had intermediate susceptibility to fluconazole. The overall 30-day mortality was 12% and significant risk factors for mortality on multivariate analysis were male sex, liver disease and mucositis.

CONCLUSIONS

Our study outlines low rates of disseminated candidiasis and low mortality associated with candidemia at our institution. Additionally, it suggests that prior colonization may be an important risk factor, however, this should be validated in large prospective controlled studies.

Prevalence and Antifungal Susceptibility of Candida parapsilosis Species Complex in Eastern China: A 15-Year Retrospective Study by ECIFIG

Candida parapsilosis complex is one of the most common non-albicans Candida species that cause candidemia, especially invasive candidiasis. The purpose of this study was to evaluate the antifungal susceptibilities of both colonized and invasive clinical C. parapsilosis complex isolates to 10 drugs: amphotericin (AMB), anidulafungin (AFG), caspofungin (CAS), micafungin (MFG), fluconazole (FLZ), voriconazole (VRZ), itraconazole (ITZ), posaconazole (POZ), 5-flucytosine (FCY), and isaconazole (ISA). In total, 884 C. parapsilosis species complex isolates were gathered between January 2005 and December 2020. C. parapsilosis, Candida metapsilosis, and Candida orthopsilosis accounted for 86.3, 8.1, and 5.5% of the cryptic species, respectively. The resistance/non-wild-type rate of bloodstream C. parapsilosis to the drugs was 3.5%, of C. metapsilosis to AFG and CAS was 7.7%, and of C. orthopsilosis to FLZ and VRZ was 15% and to CAS, MFG, and POZ was 5%. The geometric mean (GM) minimum inhibitory concentrations (MICs) of non-bloodstream C. parapsilosis for CAS (0.555 mg/L), MFG (0.853 mg/L), FLZ (0.816 mg/L), VRZ (0.017 mg/L), ITZ (0.076 mg/L), and POZ (0.042 mg/L) were significantly higher than those of bloodstream C. parapsilosis, for which the GM MICs were 0.464, 0.745, 0.704, 0.015, 0.061, and 0.033 mg/L, respectively (P < 0.05). The MIC distribution of the bloodstream C. parapsilosis strains collected from 2019 to 2020 for VRZ, POZ, and ITZ were 0.018, 0.040, and 0.073 mg/L, significantly higher than those from 2005 to 2018, which were 0.013, 0.028, and 0.052 mg/L (P < 0.05). Additionally, MIC distributions of C. parapsilosis with FLZ and the distributions of C. orthopsilosis with ITZ and POZ might be higher than those in Clinical and Laboratory Standards Institute studies. Furthermore, a total of 143 C. parapsilosis complex isolates showed great susceptibility to ISA. Overall, antifungal treatment of the non-bloodstream C. parapsilosis complex isolates should be managed and improved. The clinicians are suggested to pay more attention on azoles usage for the C. parapsilosis complex isolates. In addition, establishing the epidemiological cutoff values (ECVs) for azoles used in Eastern China may offer better guidance for clinical treatments. Although ISA acts on the same target as other azoles, it may be used as an alternative therapy for cases caused by FLZ- or VRZ-resistant C. parapsilosis complex strains.

Molecular Characterization of Candida parapsilosis by Microsatellite Typing and Emergence of Clonal Antifungal Drug Resistant Strains in a Multicenter Surveillance in China

Candida parapsilosis is an important species causing invasive candidiasis (IC) in China. The present survey was a national multicenter study of the molecular epidemiology and antifungal susceptibility profiles of C. parapsilosis. Non-duplicate C. parapsilosis isolates were collected from 10 hospitals across China in the CHIF-NET program 2016–2017. Isolates were genotyped using four highly polymorphic microsatellite markers, and susceptibility profiles determined using Sensititre YeastOne^TM YO10. A total of 319 C. parapsilosis from separate patients with IC were studied; 49.2, 17.9, and 10.3% isolates were from patients in surgical departments, general intensive care units (ICUs) and neonatal ICUs (NICU), respectively. C. parapsilosis showed good susceptibility to nine antifungal drugs. Microsatellite analysis identified 122 microsatellite (MT) types. Most MT types had sporadic distribution. However, we identified 32 clusters across 10 hospitals; seven clusters were caused by seven endemic genotypes involving five or more isolates in hospitals designated as H01, H02, H06, and H10. These clusters mainly affected surgical departments and ICUs, except for genotype MT42 which was seen in 22 patients from NICU (hospital H06). Of 16 fluconazole-resistant isolates, seven from hospital H02 shared the same genotype MT70, and three from hospital H04 were of genotype MT47. For 37 isolates with non-wild type MICs to 5-flucytosine, 29 were from hospital H01 (genotype MT48). Here we present the first nationwide molecular epidemiology study of C. parapsilosis in China, identified several previously unrecognized clusters, which included antifungal drug resistant isolates. These findings provide important data for control of IC in China.

Detection of neonatal unit clusters of Candida parapsilosis fungaemia by microsatellite genotyping: Results from laboratory-based sentinel surveillance, South Africa, 2009-2010

Neonatal candidaemia is a common, deadly and costly hospital-associated disease. To determine the genetic diversity of Candida parapsilosis causing fungaemia in South African neonatal intensive care units (NICUs). From February 2009 through to August 2010, cases of candidaemia were reported through laboratory-based surveillance. C. parapsilosis isolates from neonatal cases were submitted for identification by internal transcribed spacer (ITS) region sequencing, antifungal susceptibility testing and microsatellite genotyping. Cluster analysis was performed using Unweighted Pair Group Method with Arithmetic Mean (UPGMA). Of 1671 cases with a viable Candida isolate, 393 (24%) occurred among neonates. Isolates from 143 neonatal cases were confirmed as C. parapsilosis sensu stricto. Many isolates were resistant to fluconazole (77/143; 54%) and voriconazole (20/143; 14%). Of 79 closely-related genotypes, 18 were represented by ≥2 isolates; 61 genotypes had a single isolate each. Seven clusters, comprised of 82 isolates, were identified at five hospitals in three provinces. Isolates belonging to certain clusters were significantly more likely to be fluconazole resistant: all cluster 7 isolates and the majority of cluster 4 (78%), 5 (89%) and 6 (67%) isolates (P<.001). Candida parapsilosis-associated candidaemia in public-sector NICUs was caused by closely related genotypes and there was molecular evidence of undetected outbreaks as well as intra-hospital transmission.

Risk Factors for Candidemia in Pediatric Patients With Congenital Heart Disease

Objective.

To identify the main risk factors for the acquisition of candidemia in children with congenital heart disease (CHD) in order to improve the clinical management of these patients.

Design.

A case-control study.

Setting.

A large tertiary-care referral center in Spain with a pediatric intensive care unit (PICU) to which more than 500 children with CHD are admitted annually.

Patients.

All patients had CHD and were admitted to the PICU during 1995-2000. Case patients were defined as patients with candidemia, and control patients were defined as patients without candidemia.

Results.

Twenty-eight case patients and 47 control subjects were included in the study. Case patients were younger (mean age [ ± SD], 12.5 ± 32.0 vs 38.0 ± 48.0 months;P< .01) and had a longer median PICU stay (19 vs 4 days;P< .01), and a greater percentage of case patients previously hadCandidaspecies isolated from specimens other than blood (eg, bronchial aspirates, urine, or skin specimens) (39% vs 4%;P<.01). Severity of clinical condition, as measured by the Therapeutic Intervention Scoring System (TISS) 1 week after PICU admission (odds ratio, 1.15; 95% confidence interval, 1.05-1.26;P<.01), and receipt of antibiotic treatment for more than 5 days (odds ratio, 13.42; 95% confidence interval, 1.31-137.13;P= .03) were independently associated with the development of candidemia.

Conclusions.

Patients with CHD who have a high TISS score 1 week after PICU admission and patients who have received prolonged antibiotic therapy should be considered at high risk for candidemia. Our results suggest that shorter courses of antibiotic therapy, routine surveillance culture forCandidaspecies, and initiation of preemptive or empirical antifungal treatment could help in the clinical management of these patients.

Investigation of an unrecognized large-scale outbreak of Candida parapsilosis sensu stricto fungaemia in a tertiary-care hospital in China

A data analysis of yeast collections from the National China Hospital Invasive Fungal Surveillance Net (CHIF-NET) programme in 2013 revealed a sudden increase in the proportion of Candida parapsilosis complex isolates (n = 98) in one participating hospital (Hospital H). Out of 443 yeast isolates submitted to the CHIF-NET reference laboratory by Hospital H (2010–2014), 212 (47.9%) were identified as C. parapsilosis sensu stricto by sequencing analysis of the internal transcribed spacer region and D1/D2 domain of the 26S rRNA gene. Among the 212 C. parapsilosis sensu stricto isolates, 176 (83.0%) bloodstream-based isolates and 25 isolates from tip cultures of various vascular catheters from 25 patients with candidaemia, were subjected to microsatellite genotyping, and a phylogenetic relationship analysis was performed for 152 isolates. Among the 152 isolates, 45 genotypes (T01 to T45) were identified, and two prevalent genotypes (63.8%) were found: T15 (n = 74, 48.7%) and T16 (n = 23, 15.1%). These two main clones were confined mainly to three different wards of the hospital, and they persisted for 16–25 months and 12–13 months, respectively. The lack of proper coordination between the clinical microbiology laboratory and infection control staff as part of public health control resulted in the failure to timely identify an outbreak, which led to the wide and long-term dissemination of C. parapsilosis sensu stricto in Hospital H.

Analysis of clinical and environmental Candida parapsilosis isolates by microsatellite genotyping--a tool for hospital infection surveillance

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.

MALDI-TOF mass spectrometry and microsatellite markers to evaluate Candida parapsilosis transmission in neonatal intensive care units

Recent studies on outbreaks of Candida showed an increased incidence of bloodstream infections in neonatal intensive care units (NICUs) caused by C. parapsilosis species, highlighting the need for the proper identification and epidemiology of these species. Several systems are available for molecular epidemiological and taxonomic studies of fungal infections: pulsed-field gel electrophoresis (PFGE) represents the gold standard for typing, but is also one of the most lengthy and expensive, while simple sequence repeats (SSRs) is based on polymerase chain reaction (PCR) amplification and is, therefore, faster. Only recently, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been used to identify and type microorganisms involved in nosocomial outbreaks. In our study, 19 strains of C. parapsilosis isolated from the blood cultures of neonates admitted to the University Hospital Federico II were genotyped by the amplification of eight SSR markers and by MALDI-TOF MS. Electrophoretic and spectrometric profile results were compared in order to identify similarities among the isolates and to study microevolutionary changes in the C. parapsilosis population. The discriminatory power and the unweighted pair group method with arithmetic mean (UPGMA) dendrograms generated were compared in order to evaluate the correlation of the groups established by the analysis of the clusters by both methods. Both methods were rapid and effective in highlighting identical strains and studying microevolutionary changes in the population. Our study evidenced that mass spectroscopy is a useful technique not only for the identification but also for monitoring the spread of strains, which is critical to control nosocomial infections.

Sequence and analysis of the genome of the pathogenic yeast Candida orthopsilosis

Candida orthopsilosis is closely related to the fungal pathogen Candida parapsilosis. However, whereas C. parapsilosis is a major cause of disease in immunosuppressed individuals and in premature neonates, C. orthopsilosis is more rarely associated with infection. We sequenced the C. orthopsilosis genome to facilitate the identification of genes associated with virulence. Here, we report the de novo assembly and annotation of the genome of a Type 2 isolate of C. orthopsilosis. The sequence was obtained by combining data from next generation sequencing (454 Life Sciences and Illumina) with paired-end Sanger reads from a fosmid library. The final assembly contains 12.6 Mb on 8 chromosomes. The genome was annotated using an automated pipeline based on comparative analysis of genomes of Candida species, together with manual identification of introns. We identified 5700 protein-coding genes in C. orthopsilosis, of which 5570 have an ortholog in C. parapsilosis. The time of divergence between C. orthopsilosis and C. parapsilosis is estimated to be twice as great as that between Candida albicans and Candida dubliniensis. There has been an expansion of the Hyr/Iff family of cell wall genes and the JEN family of monocarboxylic transporters in C. parapsilosis relative to C. orthopsilosis. We identified one gene from a Maltose/Galactoside O-acetyltransferase family that originated by horizontal gene transfer from a bacterium to the common ancestor of C. orthopsilosis and C. parapsilosis. We report that TFB3, a component of the general transcription factor TFIIH, undergoes alternative splicing by intron retention in multiple Candida species. We also show that an intein in the vacuolar ATPase gene VMA1 is present in C. orthopsilosis but not C. parapsilosis, and has a patchy distribution in Candida species. Our results suggest that the difference in virulence between C. parapsilosis and C. orthopsilosis may be associated with expansion of gene families.

Transcriptional profiling of azole-resistant Candida parapsilosis strains

Herein we describe the changes in the gene expression profile of Candida parapsilosis associated with the acquisition of experimentally induced resistance to azole antifungal drugs. Three resistant strains of C. parapsilosis were obtained following prolonged in vitro exposure of a susceptible clinical isolate to constant concentrations of fluconazole, voriconazole, or posaconazole. We found that after incubation with fluconazole or voriconazole, strains became resistant to both azoles but not to posaconazole, although susceptibility to this azole decreased, whereas the strain incubated with posaconazole displayed resistance to the three azoles. The resistant strains obtained after exposure to fluconazole and to voriconazole have increased expression of the transcription factor MRR1, the major facilitator transporter MDR1, and several reductases and oxidoreductases. Interestingly, and similarly to what has been described in C. albicans, upregulation of MRR1 and MDR1 is correlated with point mutations in MRR1 in the resistant strains. The resistant strain obtained after exposure to posaconazole shows upregulation of two transcription factors (UPC2 and NDT80) and increased expression of 13 genes involved in ergosterol biosynthesis. This is the first study addressing global molecular mechanisms underlying azole resistance in C. parapsilosis; the results suggest that similarly to C. albicans, tolerance to azoles involves the activation of efflux pumps and/or increased ergosterol synthesis.

Molecular epidemiology and antifungal susceptibility of Candida parapsilosis sensu stricto, Candida orthopsilosis, and Candida metapsilosis in Taiwan

Candida parapsilosis was recently reclassified into 3 closely related species, C. parapsilosis sensu stricto, Candida orthopsilosis, and Candida metapsilosis. Variation in susceptibility characteristics and prevalence of the 3 genomic species could have therapeutic and epidemiologic implications. The aim of this study is to characterize the genetic and antifungal susceptibility profiles of 97 C. parapsilosis isolates from 71 patients. Among the 71 nonduplicate isolates, 85.9% (61/71) were identified as C. parapsilosis sensu stricto, 5.6% (4/71) as C. metapsilosis, and 8.5% (6/71) as C. orthopsilosis species based on sequences of the internal transcribed spacer (ITS) region. The delineation of these 3 species is concordant with that achieved by pulsed-field gel electrophoresis of BssHII restriction fragments at 75% similarity. Antifungal susceptibility tests showed that most isolates were susceptible to flucytosine, azoles, amphotericin B, and echinocandins, whereas 3 C. metapsilosis isolates from 1 patient showed resistance and susceptible-dose dependence to fluconazole. The C. metapsilosis isolates exhibited significantly higher MIC values to both fluconazole and voriconazole than those of C. parapsilosis sensu stricto and C. orthopsilosis. On the other hand, the C. metapsilosis isolates showed significantly lower MIC values on 24 h to caspofungin than those of C. parapsilosis sensu stricto and C. orthopsilosis. For micafungin, the isolates of C. parapsilosis sensu stricto had significantly higher MIC values on 24 h than those of C. orthopsilosis and C. metapsilosis. Compared to Candida albicans, mutations from proline to alanine were identified on the hot spot 1 of Fks1 in all these C. parapsilosis sensu lato isolates regardless of their MIC levels. Some of the C. orthopsilosis and C. metapsilosis isolates expressed the isoleucine to valine substitution on the hot spot 2 region. However, the amino acid variations in these isolates did not correlate to their MIC values of echinocandin.

Candida parapsilosis: a review of its epidemiology, pathogenesis, clinical aspects, typing and antimicrobial susceptibility

The Candida parapsilosis family has emerged as a major opportunistic and nosocomial pathogen. It causes multifaceted pathology in immuno-compromised and normal hosts, notably low birth weight neonates. Its emergence may relate to an ability to colonize the skin, proliferate in glucose-containing solutions, and adhere to plastic. When clusters appear, determination of genetic relatedness among strains and identification of a common source are important. Its virulence appears associated with a capacity to produce biofilm and production of phospholipase and aspartyl protease. Further investigations of the host-pathogen interactions are needed. This review summarizes basic science, clinical and experimental information about C. parapsilosis.

Prevalence, distribution, and antifungal susceptibility profiles of Candida parapsilosis, C. orthopsilosis, and C. metapsilosis in a tertiary care hospital

Candida parapsilosis, an emergent agent of nosocomial infections, was previously made up of a complex of three genetically distinct groups (groups I, II, and III). Recently, the C. parapsilosis groups have been renamed as distinct species: C. parapsilosis sensu stricto, C. orthopsilosis, and C. metapsilosis. In Portugal, no data pertaining to the distribution and antifungal susceptibility of these Candida species are yet available. In the present report, we describe the incidence and distribution of C. parapsilosis sensu stricto, C. orthopsilosis, and C. metapsilosis among 175 clinical and environmental isolates previously identified by conventional methods as C. parapsilosis. We also evaluated the in vitro susceptibilities of the isolates to fluconazole, voriconazole, posaconazole, amphotericin B, and two echinocandins, caspofungin and anidulafungin. Of the 175 isolates tested, 160 (91.4%) were identified as C. parapsilosis sensu stricto, 4 (2.3%) were identified as C. orthopsilosis, and 5 (2.9%) were identified as C. metapsilosis. Six isolates corresponded to species other than the C. parapsilosis group. Interestingly, all isolates from blood cultures corresponded to C. parapsilosis sensu stricto. Evaluation of the antifungal susceptibility profile showed that only nine (5.6%) C. parapsilosis sensu stricto strains were susceptible-dose dependent or resistant to fluconazole, and a single strain displayed a multiazole-resistant phenotype; two (1.3%) C. parapsilosis sensu stricto strains were amphotericin B resistant. All C. orthopsilosis and C. metapsilosis isolates were susceptible to azoles and amphotericin B. A high number of strains were nonsusceptible to the echinocandins (caspofungin and anidulafungin).

Molecular epidemiology of Candida species isolated from clinical specimens of intensive care unit patients

Epidemiological analysis of nosocomial Candida infections has gained importance due to an increase in these infections during the recent years. This study investigated the prevalence of clinical infections of Candida in anesthesiology intensive care unit patients, and ascertains the level of genetic diversity in the Candida species. A total of 70 Candida isolates, consisting of 42 Candida albicans, 16 Candida glabrata and 12 Candida tropicalis strains isolated from various clinical sites of infection of anesthesiology intensive care unit patients, were analysed. The susceptibility of the isolates against amphotericin B and fluconazole was determined by microdilution method according to Clinical and Laboratory Standards Institute M27-A2 standards. The strains were typed by random amplified polymorphic DNA (RAPD)-PCR using OPE-03, OPE-18, RP4-2 and AP50-1 primers. In the patients with Candida infections, most isolates exhibited different RAPD patterns. Only three C. albicans pairs isolated within a short time period had the same RAPD pattern. Most of the Candida infections in the anesthesiology intensive care unit of our hospital seem to be caused by endogenous strains. Exogenous spread of C. albicans infections occurred less frequently.

Candidemia in pediatric patients with congenital heart disease

Candidemia is an important problem in pediatrics. In our hospital, highest candidemia rates were documented among children with congenital heart disease (CHD). A series was conducted to describe the clinical and mortality features of candidemia in these patients. Fifty-two cases (1988-2000) included very young infants (median age, 2 months) who received long-term antibiotic treatment (median, 20.5 days). Candida parapsilosis predominated (54%). Endovascular infections occurred in 11.5%. In-hospital mortality was 39% and related mortality 14%. Maintenance of catheter (odds ratio [OR], 6.0; 95% confidence interval [CI], 1.0-37.2; P = .05) and severity of patients as measured with the Pediatric Risk Score of Mortality I (OR, 1.1, 95% CI, 1.0-1.3; P = .05) were independently associated with mortality. In summary, candidemia in children with CHD is diagnosed to very young infants with prolonged antibiotic therapy. Mortality is high but, in most cases, is not related to candidemia. Optimal management may include exclusion of endocarditis, early antifungal treatment, and catheter removal.

Molecular genotyping of Candida parapsilosis group I clinical isolates by analysis of polymorphic microsatellite markers

Candida parapsilosis, a pathogenic yeast, is composed of three newly designated genomic species that are physiologically and morphologically indistinguishable. Nosocomial infections caused by group I C. parapsilosis are often associated with the breakdown of infection control practices and the contamination of medical devices, solutions, and indwelling catheters. Due to the low levels of nucleotide sequence variation that are observed, an investigation of the size polymorphisms in loci harboring microsatellite repeat sequences was applied for the typing of C. parapsilosis group I isolates. PCR primer sets that flank the microsatellite repeats for seven loci were designed. Following amplification by PCR, the size of each amplification product was determined automatically by capillary electrophoresis. A total of 42 C. parapsilosis group I isolates were typed by microsatellite analysis, and their profiles were compared to the hybridization profiles obtained by use of the Cp3-13 DNA probe. A high degree of discrimination (discriminatory power = 0.971) was observed by microsatellite analysis. The number of different alleles per locus ranged from 14 for locus B to 5 for locus C. Microsatellite analysis detected 30 different microsatellite genotypes, with 24 genotypes represented by a single isolate. Comparison of the genotypes obtained by microsatellite analysis and those obtained by analysis of the Cp3-13 hybridization profiles showed that they were similar, and these methods were able to identify related and unrelated isolates. Some discrepancies were observed between the methods and may be due to higher mutation rates and/or homoplasy by microsatellite markers. Identical results were observed between microsatellite analysis and Cp3-13 DNA hybridization profile analysis for C. parapsilosis isolates obtained from two patients, demonstrating the reproducibilities of the methods in vivo. Identical microsatellite profiles were observed for isolates displaying different phenotypic switching morphologies. Indistinguishable Cp3-13 DNA hybridization profiles were observed for six epidemiologically related isolates; however, only three of six primary isolates had identical microsatellite profiles. Size variation at a single locus was observed for three of six isolates obtained either after the outbreak period or from a different body site, suggesting the potential of the method to detect microevolutionary events. Interestingly, for most loci a single allele per strain was observed; in contrast, two alleles per locus were observed for some strains, and consistent with the findings for natural isolates, some isolates may be aneuploid. Due to the potential for high throughput, reproducibility, and discrimination, microsatellite analysis may provide a robust and efficient method for the genotyping of large numbers of C. parapsilosis group I isolates.

Current awareness on yeast

In order to keep subscribers up‐to‐date with the latest developments in their field, this current awareness service is provided by John Wiley & Sons and contains newly‐published material on yeasts. Each bibliography is divided into 10 sections. 1 Books, Reviews & Symposia; 2 General; 3 Biochemistry; 4 Biotechnology; 5 Cell Biology; 6 Gene Expression; 7 Genetics; 8 Physiology; 9 Medical Mycology; 10 Recombinant DNA Technology. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted. (4 weeks journals ‐ search completed 10th. Nov. 2004)