Original article
Molecular characterization of Candida isolates from intensive care unit patients, Krakow, PolandCaracterización molecular de aislamientos de Candida de pacientes en cuidados intensivos en Cracovia, Polonia

https://doi.org/10.1016/j.riam.2016.03.005Get rights and content

Abstract

Background

Over the last decades, Candida species have emerged as important pathogens in immunocompromised patients. Nosocomial infections are mainly of endogenous origin. Nevertheless, some cases of exogenous candidiasis have also been reported.

Aims

The aim of this study was to evaluate the genetic relatedness between Candida albicans, Candida glabrata, Candida tropicalis, Candida krusei and Candida kefyr isolates recovered from intensive care unit (ICU) patients.

Methods

A total of 132 Candida clinical isolates (62 C. albicans, 40 C. glabrata, 13 C. tropicalis, 11 C. krusei, 6 C. kefyr), obtained from specimens of endotracheal aspirate, urine and blood taken from patients of a tertiary hospital in Poland, were included in the study. Species identification was performed by PCR method and genetic relatedness was assessed by randomly amplified polymorphic DNA assay (RAPD) with five primers.

Results

The RAPD analysis revealed high genetic diversity among the studied Candida isolates, indicating that most of the strains were from endogenous sources. Only two clonal strains of C. glabrata isolated from different patients were observed, suggesting a possible cross-transmission of these pathogens.

Conclusions

Our study confirmed the high discriminatory power of the RAPD assay. This genotyping method can be applied to local epidemiological studies of Candida species.

Resumen

Antecedentes

En las últimas décadas, el hongo Candida se ha convertido en un patógeno importante para los pacientes con trastornos del sistema inmune. Las infecciones nosocomiales son fundamentalmente de origen endógeno; sin embargo, también se han documentado algunos casos de candidiasis exógena.

Objetivos

El objetivo del estudio fue evaluar la relación genética entre las cepas de Candida albicans, Candida glabrata, Candida tropicalis, Candida krusei y Candida kefyr aisladas de pacientes en cuidados intensivos.

Métodos

Se estudiaron 132 aislamientos de Candida (62 C. albicans, 40 C. glabrata, 13 C. tropicalis, 11 C. krusei, 6 C. kefyr) obtenidos de muestras procedentes de aspirado endotraqueal, orina y sangre tomadas de pacientes de un hospital en Polonia. La identificación de las especies se realizó mediante PCR, y el estudio de la relación genética con el método de amplificación aleatoria de ADN polimórfico (RAPD) con cinco oligonucleótidos.

Resultados

El análisis de la amplificación por RAPD mostró una alta diversidad genética entre los aislamientos objeto de estudio, lo que indica que la mayoría de ellos tenían un origen endógeno. Solo se observaron dos cepas clonales de C. glabrata procedentes de diferentes pacientes, lo que evidencia una posible transmisión cruzada de estos patógenos.

Conclusiones

Nuestro estudio confirma el alto poder discriminatorio de la técnica RAPD, lo que validaría este método de genotipificación para el estudio de la epidemiología local de especies de Candida.

Section snippets

Patients and strains

One hundred and twenty three patients with multi-organ failure were enrolled into the study. They were hospitalised between 2009 and 2012 at the Intensive Care Unit of Ludwik Rydygier Memorial Hospital in Krakow. The study population consisted of 74 (60.2%) males and 49 (39.8%) females with the average age of 64 years (range 18–93) from south-eastern Poland. Antifungal prophylaxis had not been administered to the patients included in this study.

The predominant fungal species isolated in the

Results

All the 62 isolates subjected to PCR assay using primers targeting the HWP1 gene were identified as C. albicans, as a ∼1000-bp fragment was amplified. In the remaining 40 isolates, analyzed with the use of the primers for amplification of the ITS region, a ∼420-bp band, specific for C. glabrata was detected (Fig. 1).

The MIC50 and MIC90 values of amphotericin B, fluconazole, 5-fluorocytosine and voriconazole for C. albicans, C. glabrata, C. tropicalis, C. krusei and C. kefyr isolates are shown

Discussion

The yeasts belonging to the Candida genus are recognized as the dominant human pathogenic fungi. They affect hospitalized patients with systemic life-threatening infections.

Because of a documented increase in the incidence of new emerging species closely related to C. albicans and C. glabrata, application of PCR-based molecular methods to identify them is crucial.6, 7, 32, 33 The identification by phenotypic methods (e.g. chromogenic media or automatic systems) may be inconclusive, therefore

Conflict of interest

The authors declare that there are no conflicts of interest.

Acknowledgements

The scientific work was supported by the Jagiellonian University Medical College with funds from maintenance of the research potential of the JU MC Department of Pharmaceutical Microbiology.

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