Efficacy of discontinuous density gradient combined with swim-up method for bacterial removal in frozen semen
10.3969/j.issn.1006-5725.2025.18.008
- VernacularTitle:非连续密度梯度法联合上游法在冷冻精液除菌中的应用
- Author:
Jiaming ZHUANG
1
;
Lulu LUO
1
;
Yingyi ZHOU
1
;
Chunjie MA
1
Author Information
1. 广东省生殖科学研究所(广东省生殖医院)国家卫生健康委员会男性生殖与遗传重点实验室(广东 广州 510600)
- Publication Type:Journal Article
- Keywords:
frozen semen;
microbial contamination;
discontinuous density gradient method;
swim-up method;
assisted reproductive technology
- From:
The Journal of Practical Medicine
2025;41(18):2839-2843
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the efficacy of discontinuous density gradient combined with swim-up method for bacterial removal in frozen semen,and to provide experimental evidence for the safe application of frozen semen in assisted reproductive technology.Methods A total of 208 frozen semen samples containing non-pathogenic bacteria,cryopreserved in our human sperm bank from January 2019 to December 2023,were selected.The thawed semen samples were processed using discontinuous density gradient combined with swim-up method.To simulate in vitro fertilization procedures,the processed sperm suspensions were subjected to 5-day in vitro culture for bacterial residue monitoring.Prior to cryopreservation,all semen samples underwent routine bacterial culture to exclude pathogenic microorganisms.Post-thaw semen samples,processed sperm suspensions,and 5-day culture media were sent to an independent third-party laboratory for comprehensive bacterial identification.Results Among the 208 frozen semen samples containing non-pathogenic bacteria,41 bacterial species were identified,with 1～4 species per sample.After processing with discontinuous density gradient combined with swim-up method,the sterility rate of the sperm suspension reached 89.42%(186/208),with residual bacteria including Enterococcus faecalis,Corynebacterium glucuronolyticum,Group B Streptococcus,and Corynebacterium glycinophilum.After 5-day in vitro culture,the sterility rate increased to 93.75%(195/208),with residual bacteria limited to Entero-coccus faecalis and Group B Streptococcus.Conclusions The combined method of discontinuous density gradient and swim-up technique effectively eliminates most bacteria in frozen semen.However,the clearance rate for Entero-coccus faecalis and Group B Streptococcus remains below 90%.Optimization of pre-freezing bacterial screening and post-thaw processing techniques is necessary to enhance the safety of frozen semen in assisted reproductive technology.
