Case Report: Successful removal of Candida parapsilosis from human embryos with the application of laser and micromanipulation techniques

Abstract

Objective To describe a micromanipulation method for removal of yeast from contaminated embryos to rescue their development Design Review of 2 concurring IVF/ICSI cases resulting in blastocysts colonized by Candida parapsilosis. Method of yeast removal, isolation and identification of yeast species, and cycle outcome is reviewed. Materials and methods Mature oocytes retrieved from patients were injected with their partner's sperm and cultured under standard conditions. At fertilization, zygotes from two patients showed a contaminating mass in the culture droplets. Embryos from contaminated drops were rinsed multiple times and cultured in freshly equilibrated culture media. The following day culture media had no visual contamination. However, one patient's embryos had hyphae-like masses attached to their zonae pellucidae. Under an inverted microscope attached to a micromanipulator, embryos were held under suction. Hyphae-like masses were removed by applying suction through an assisted hatching pipette and firing a laser to facilitate the detachment of contaminating masses. Cleaned embryos were rinsed and cultured through day 6. All freezable quality blastocysts were vitrified on either day 5/6. Samples of visually contaminated culture drops (Day 1), post-rinse culture drops at the time of embryo vitrification (day 5/6), and stock solutions were sent to a reference lab for microbiological analysis. Patient whose embryos had hyphae mechanically removed underwent subsequent frozen embryo transfer cycle. Results Growth media stock solutions tested positive for Candida parapsilosis. Conclusion Candida parapsilosis hyphae were successfully removed from growing embryos using laser and micromanipulation techniques. After yeast contamination removal, normally developed blastocyst(s) may be transferred only after patient's consent. Disclosures None Funding None To describe a micromanipulation method for removal of yeast from contaminated embryos to rescue their development Review of 2 concurring IVF/ICSI cases resulting in blastocysts colonized by Candida parapsilosis. Method of yeast removal, isolation and identification of yeast species, and cycle outcome is reviewed. Mature oocytes retrieved from patients were injected with their partner's sperm and cultured under standard conditions. At fertilization, zygotes from two patients showed a contaminating mass in the culture droplets. Embryos from contaminated drops were rinsed multiple times and cultured in freshly equilibrated culture media. The following day culture media had no visual contamination. However, one patient's embryos had hyphae-like masses attached to their zonae pellucidae. Under an inverted microscope attached to a micromanipulator, embryos were held under suction. Hyphae-like masses were removed by applying suction through an assisted hatching pipette and firing a laser to facilitate the detachment of contaminating masses. Cleaned embryos were rinsed and cultured through day 6. All freezable quality blastocysts were vitrified on either day 5/6. Samples of visually contaminated culture drops (Day 1), post-rinse culture drops at the time of embryo vitrification (day 5/6), and stock solutions were sent to a reference lab for microbiological analysis. Patient whose embryos had hyphae mechanically removed underwent subsequent frozen embryo transfer cycle. Growth media stock solutions tested positive for Candida parapsilosis. Candida parapsilosis hyphae were successfully removed from growing embryos using laser and micromanipulation techniques. After yeast contamination removal, normally developed blastocyst(s) may be transferred only after patient's consent.