engleski

Neonatal Candida utilis candidemia and colonization : analysis of in vitro antifungal susceptibilities and molecular typing of causative isolates

The aims of this retrospective study were to investigate in vitro antifungal susceptibility profiles as well as the molecular characterization of C. utilis isolates recovered from blood samples and surveillance cultures of newborns hospitalized in the same neonatal intensive care unit (NICU) of Children's Hospital Zagreb, Croatia in the year 2008 and 2010. Blood cultures drawn from the patients were cultured in a BACTEC 9050 system (BectonDickinson) using BACTECPedsPlus/F culture vials. Yeast isolation from surveillance cultures was carried out using Sabouraud's glucose agar and Brain-Heart Infusion agar (BD Diagnostics). The ID32C method (BioMerieux) and morphology on cornmeal agar (BD Diagnostics) were used for the identification of C. utilis isolates. In vitro antifungal susceptibility testing was performed by the ATB FUNGUS 3 (BioMerieux) microdilution method, while the results were interpreted according to CLSI recommendations. Molecular typing was done by using RAPD-PCR method, which was performed according to Gardiner (Gardiner et al., 2002). In 2008 and 2010 respectively, we isolated C. utilis from blood samples and/or surveillance cultures from four neonates. Two of them developed clinically manifested C. utilis candidemia without colonization of digestive, respiratory and urogenital tract, skin and the removed CVCs, one developed candidemia and colonization of groin skin with this species, and the remainig one had colonization of upper respiratory and urinary tract without C. utilis candidemia. A total of 12 C. utilis bloodstream isolates and 4 C. utilis isolates from surveillance cultures were analyzed. In vitro antifungal MIC for C. utilis isolates were <0.5 μg/ml for amphotericin B, <4 μg/ml for flucytosine, <1 μg/ml for fluconazole and <0.062 μg/ml for voriconazole. In vitro antifungal susceptibility ranges for C. utilis isolates was <0.125-0.5 μg/ml for itraconazole. All sixteen C. utilis isolates from our patients showed the same RAPD-PCR banding pattern, indicating as being clonally related. No in vitro resistance to amphotericin B, flucytosine, fluconazole, itraconazole, and voriconazole was observed among the 16 C. utilis isolates from newborns hospitalized in NICU, all with a significant number of risk factors for the development of candidemia and colonization with this low virulent Candida species. All four newborns were on antibiotic therapy, parenteral nutrition, anti-ulcer prophylaxis, had a CVC in place, underwent a surgical procedure at birth, whereas three of them were on artificial ventilation, and two were on prophylactic fluconazole. Molecular typing of 12 blood culture isolates and 4 from the surveillance cultures demonstrated that all patients had indistinguishable strains of C. utilis. NICU staff was not found to be a potential source of infection and colonization of newborns with C. utilis. By presenting this study, our intention was to point to C. utilis, as a possible cause of candidemia and colonization among the hospitalised newborns, especially since this Candida species has been rarely described as an infectious agent in adults and children and even less in newborns.

Candida utilis; neonatal candidemia; antifungal susceptibility; molecular typing

DOI: 10.1111/j.1439-0507.2011.02092.x