Microbial contamination of embryo cultures in an ART laboratory: sources and management

Abstract

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.

Transfer of IVF-contaminated blastocysts with removal of the zona pellucida resulted in live births

“…A recent review by Pomeroy [7] supports that microbes from the non-sterile IVF culture system and non-sterile oocyte and semen collection process are the most common sources of contamination. In both cases, contamination was observed only in microdrops containing embryos from conventional insemination but not ICSI, which is consistent with Kastrop et al [1], where bacterial contamination was observed in 95 IVF cycles (0.68 %) while no bacterial contamination was observed in 2926 ICSI cycles. Two important sources of contamination during embryo culture are semen and follicular fluids.…”

“…To minimize the adverse effects of bacterial contamination on embryonic development, cultured embryos should be removed from microdrops once contamination is identified. In most published reports, embryonic development was poor if embryo culture dishes were contaminated with bacteria [1]. Of the 20 embryos contaminated from the two cases of our report, 11 (55 %) developed to goodquality blastocysts that were either transferable or freezable.…”

“…ICSI procedure reduces risk of colonization of the culture dishes by microorganisms and should be offered for those patients with a previous infection of the IVF culture dishes. Identification of the contaminating microorganisms showed that infections in IVF culture dishes were mainly caused by bacterial strains insensitive to the antibiotics contained in culture media or due to yeast colonization by Candida species which frequently reside in the vagina [1].…”

“…By reviewing 13,977 IVF cycles over a period of 8 years, Kastrop et al [1] reported 95 infections of IVF culture dishes (0.68 %). Considering the large number of IVF cycles performed, thousands of IVF microbial contaminations occur every year.…”

Embryo Culture Challenge: Microbial Contamination

“…Results of intensive studies regarding the identification of the main sources of such contamination reveled that Escherichia coli (E. coli) and Candida species have caused more than 59 % and 26 % of these contaminations, respectively (6)(7)(8). Among E. coli species, 74 % showed a great resistant to both Penicillin and Streptomycin in the culture medium.…”