Microbial contamination of embryo cultures in an ART laboratory: sources and management.
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.
Kastrop
Peter M M
PM
Department of Reproductive Medicine, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands. p.kastrop@umcutrecht.nl
de Graaf-Miltenburg
Lia A M
LA
Gutknecht
Dagmar R
DR
Weima
Sjerp M
SM
D002175:Candida / Q000302:isolation & purification; D046149:Embryo Culture Techniques / Q000592:standards; D004926:Escherichia coli / Q000302:isolation & purification; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008297:Male; D009865:Oocytes / Q000382:microbiology*; D012189:Retrospective Studies; D012661:Semen / Q000382:microbiology*; D020554:Sperm Injections, Intracytoplasmic