Infection in a neonate caused byPichia fabianii: Importance of molecular identification

Abstract

Pichiafabianii, an uncommon yeast species recovered from clinical specimens, was documented as the cause of an infection in a 5-week-old female twin delivered at 25 and 3/7 weeks. She developed respiratory distress syndrome and necrotizing enterocolitis. At the time of the infection, she was febrile, thrombocytopenic, and still was requiring minimal ventilatory support. Blood cultures drawn on two consecutive days were positive for a germ tube negative yeast. Phenotypic methods including carbohydrate fermentations and assimilations (API 20C AUX) did not identify the yeast. Sequencing of D1/D2 domain of the large subunit rDNA was performed in one laboratory and sequencing a subunit of D2 performed in a second laboratory identified the yeast as P. fabianii. The organism was susceptible in vitro to amphotericin B, fluconazole and 5-fluorocytosinc. The patient responded to amphotericin B and removal of her vascular catheter. This case illustrates that there are an increasing number of fungi that may be pathogenic. Phenotypic tests may fail to identify them, emphasizing the need for commercially available, molecular based assays for identification.

Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Fast and Reliable Identification of Clinical Yeast Isolates

“…Interestingly, and in agreement with our observation (Table 3), in the endocarditis case reported by Hamal et al (16), the isolates were initially identified biochemically as Candida pelliculosa; however, on the basis of direct sequencing of the internal transcribed spacer region of rRNA, they were subsequently reidentified as Pichia fabianii with strong biofilm formation and voriconazole resistance. Pichia fabianii is an example of a yeast species which requires molecular techniques for correct identification (5).…”

Evaluation of Pyrosequencing® technology for the identification of clinically relevant non-dematiaceous yeasts and related species

“…Conventional identification of yeasts relies upon a combination of morphological and biochemical features using tests that may require relatively long periods of incubation, are labor intensive and/or require subjective interpretation. Popular biochemical identification panels such as API 20C AUX or VITEK ID-YST (BioMerieux, Durham N.C) may have limited databases resulting in misidentification of some isolates [6][7][8][9]. Therefore, molecular methods offer an attractive, accurate and rapid alternative for the identification of pathogenic yeast.…”

Rapid Molecular Identification of Pathogenic Yeasts by Pyrosequencing Analysis of 35 Nucleotides of Internal Transcribed Spacer 2

“…Indeed, previous studies have demonstrated that such methods frequently fail to identify the less common pathogens and those common organisms that are misbehaving (1,15) or to discriminate between closely related species (15,27). Molecular identification, employing PCR amplification and sequencing of genomic regions that evolve slowly and that show high degrees of conservation, represents a rapid and sensitive alternative to conventional identification for yeasts and is also useful for the establishment of phylogenetic relationships.…”