Antimicrobial activity of human cervical mucus

The antibacterial activity of human cervical mucus (CM) was examined on sta ndardized microbial colonized agar plates (agar diffusion test). In paralle l, the lysozyme content of CM was determined by means of a turbidimetric te st system in aliquots of the same CM specimens. Suspensions of living lyoph ilized Micrococcus lysedeikticus were used as bacterial substrate Testing w as performed in a total of 133 CM samples, obtained at mid-cycle from sexua lly active women from unselected infertile couples with a median age of 30 (range 21-42) years, All mucus specimens showed considerable antibacterial activity with clearly visible circular inhibition zones around the CM-fille d holes in the colonized agar plates. Related to the effect of hen's egg wh ite (HEW)-lysozyme on the same plates, the median activity of the CM specim ens in the agar diffusion test was equivalent to 33.0 (range 6.4-391.4) mu g/ml HEW-lysozyme. However, there was a wide inter-individual range of anti bacterial effects of cervical secretions. The cervical index did not. signi ficantly influence the outcome of either test. The pH of the endocervical C M also was not correlated with the antibacterial effect. Sexual activity le ading to the presence of spermatozoa in CM considerably increased its antib acterial effect. The activity tvas markedly higher in samples obtained with in hours after intercourse compared with those taken after sexual abstinenc e of greater than or equal to 5 days (P < 0.05). In microbially colonized C M specimens compared to sterile CM, all obtained under hormonally standardi zed conditions, the antibacterial activity in the agar plate test was signi ficantly lower (P < 0.05), The results of this pilot study demonstrate the considerable antibacterial activity of human CM.