A medium for the cultivation of Trichomonas vaginalis.
Typical Formula* | gm/litre |
Liver digest | 25.0 |
Glucose | 5.0 |
Sodium chloride | 6.5 |
Agar | 1.0 |
pH 6.4 ± 0.2 @ 25°C | |
* Adjusted as required to meet performance standards
Directions
Suspend 37.5g in 1 litre of distilled water and bring to the boil to dissolve. Sterilise by autoclaving at 121°C for 15 minutes. Cool to approximately 50°C. Inactivate 80ml of horse serum †, adjust to pH 6.0 and add it to the medium. For diagnostic work, bacterial growth may be suppressed by the addition of 1000 units of penicillin and 500µg of streptomycin per ml of medium or 100µg of chloramphenicol per ml of medium (1 vial of SR0078 per 500ml medium).
† Prior to incorporation in the medium, Horse Serum SR0035 is inactivated by maintaining at a temperature of 56°C for 30 minutes, and then acidified with 1N hydrochloric acid to pH 6.0.
Description
A medium based on that of Feinberg & Whittington1 for the detection of Trichomonas vaginalis and Candida spp. The authors, after a series of investigations on 1,704 genito-urinary specimens, found that Trichomonas vaginalis would not have been detected in 23.5% of the samples had they not been cultured. Furthermore, out of 747 vaginal specimens, 63% which were positive would have been dismissed as negative without use of the medium.
Stenton2 noted that the success of an earlier version of the Trichomonas Medium was largely dependent on the choice and percentage of liver incorporated and he selected Oxoid Liver Infusion. Trichomonas Medium has been slightly modified by the incorporation of 0.1% w/v of agar which leads to reduced oxygen tension and consequently more prolific growth of trichomonads. Good growth of both Trichomonas and Candida may be obtained in mixed culture - the growth of Candida spp. seldom interferes with trichomonads.
Technique
Inoculate Trichomonas Medium and incubate at 35°C for three to five days. At intervals, microscopically examine medium taken from the bottom of the tube. In addition, microscopically examine fresh wet smears of the specimen at the time of initial culture.
The medium is equally suitable for the examination of urethral and vaginal swabs, and urine specimens.
Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared medium at 2-8°C.
Appearance
Dehydrated medium: Light straw coloured, free-flowing powder
Prepared medium: Dark straw coloured solution