Abstract:

Objective To optimize culture methods and processes for mycoplasma and to establish a new scheme to improve the detection accuracy of ureaplasma urealyticum (Uu) and mycoplasma hominis (Mh) infections.Methods A practical standard laboratory procedure was established, and the models of mycoplasma culture in solid and liquid cultures were optimized. A total of 11 hospitals above Grade 2 in Shanghai participated in the study. Study cases were randomly selected, and genitourinary samples were determined. Statistical analysis was performed, and the clinical application of the procedure was evaluated. Results A total of 747 samples were collected. The overall positive rate was 45.1% (337/747), for Uu 41.1% (307/747) and for Mh 13.9% (104/747). The positive coincidence percentages of original sample inoculation were 92.6% and 94.0% (P<0.01), respectively. The positive coincidence percentages after transmission inoculation were 97.5% and 96.1% (P>0.05). The sensitivity of solid culture was improved when culture was transferred from liquid culture with color changes. A total of 17 liquid culture samples did not produce any colonies on the solid culture, and even the solid culture was passed twice. This indicated that solid culture decreased the false positivity in liquid culture. The determination time reduced significantly when solid and liquid cultures were performed simultaneously. Over 85% mycoplasma samples had colony formation within 24 h, and in 48 h liquid culture and solid culture had same positive percentage. Conclusions The combination of liquid culture and solid culture of mycoplasma produces high sensitivity and specificity, although the costs of the testing increase. This combination determination procedure should be recommended in the laboratory diagnosis of mycoplasma infections.

Key words: Mycoplasma, Ureaplasma urealyticum, Mycoplasma hominis, Culture, Determination method, Standardization