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Microbial contamination of embryo cultures in an ART laboratory: sources and management
Peter M M Kastrop1, Lia A M de Graaf-Miltenburg, Dagmar R Gutknecht
1Department of Reproductive Medicine, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands. p.kastrop@umcutrecht.nl
Background:
Although rare, microbial contamination of culture dishes occasionally occurs in our IVF/ICSI programme. Despite stringent culture conditions and the use of medium containing penicillin and streptomycin, an increasing number of infections was observed once they were routinely recorded. In this study, 95 cases of contaminated culture dishes were examined, in an attempt to identify possible causes.
Methods:
Relevant data of the IVF/ICSI treatment cycles and the micro-organisms isolated from the infected culture dishes were evaluated retrospectively.
Results:
Infections were observed only in IVF culture dishes and never after applying intra-cytoplasmic sperm injection. Identification of the contaminating micro-organisms showed that infections were mainly caused by Escherichia coli (n = 56; 58.9%) and Candida species (n = 24; 25.3%). Of the E. coli strains isolated, 41 (73.2%) appeared to be resistant to both antibiotics used in the culture medium and 13 (23.2%) appeared to resist either penicillin or streptomycin. Of all bacterial strains isolated, the resistances were 61.4% to both and 30% to one of the antibiotics used.
Conclusions:
Applying the ICSI procedure prevents colonization of the culture dishes by micro-organisms. Infections in IVF culture dishes are mainly caused by bacterial strains insensitive to the antibiotics used or due to yeast colonization by Candida species which frequently reside in the vagina.
Insights
Intracytoplasmic sperm injection (ICSI) prevents microbial contamination in in vitro fertilization (IVF) culture dishes. Infections, primarily by antibiotic-resistant Escherichia coli and Candida species, occur in standard IVF cultures.
Area of Science:
- Reproductive Medicine
- Microbiology
- In Vitro Fertilization
Background:
- Microbial contamination of culture dishes is a rare but recurring issue in IVF/ICSI programs.
- An increase in infections was noted despite stringent conditions and antibiotic-containing media.
- This study investigated 95 cases of contaminated culture dishes to identify root causes.
Purpose of the Study:
- To identify the causes of microbial contamination in IVF/ICSI culture dishes.
- To determine the types of microorganisms involved and their antibiotic resistance patterns.
Main Methods:
- Retrospective analysis of IVF/ICSI treatment cycles.
- Evaluation of microorganisms isolated from contaminated culture dishes.
Main Results:
- Contamination occurred exclusively in standard IVF dishes, not after ICSI.
- Escherichia coli (58.9%) and Candida species (25.3%) were the primary contaminants.
- High resistance rates to antibiotics were observed in E. coli (73.2% to both, 23.2% to one) and other bacteria (61.4% to both, 30% to one).
Conclusions:
- ICSI effectively prevents microbial colonization of culture dishes.
- IVF culture dish infections are mainly caused by antibiotic-insensitive bacteria (E. coli) or Candida species.
- Candida species, common in the vaginal flora, contribute significantly to yeast contamination.
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