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Background: Preterm birth is a multifactorial obstetric problem and inclusion of other investigative factors may improve our ability to define risk of an early onset of labour. A variety of vaginal microbiological infections have been associated with preterm birth. Appropriate recognition and effective treatment of vaginal colonization with pathogenic organisms may reduce the rate of preterm delivery. Recently, some studies have demonstrated an association between vaginal colonization bacteria and short cervical length. There are also data demonstrating the potential for molecular characterization of vaginal flora using 16S rRNA qPCR assays which may lend themselves more readily to mass screening than the current process of microbiological culture. Methods: This prospective study of pregnant and non-pregnant women was conducted between 15 April 2014 and 17 September 2014 at The Royal Prince Alfred Hospital (Women and Babies. This study involved collection of vaginal secretion samples using swabs and probe cover sheaths at the same time transvaginal scanning for either cervical length measurement or reproductive tract assessment. Two methods of sample collections were used vaginal swabs and protective condom sheath and these were stored in two different transport medias; PreservCyt solution for samples from the first vaginal swab and protective condom, and Amies agar gel medium for the second vaginal swab sample. 16S rRNA analysis was used for qPCR assays analysis of the four selected bacterial species: L. iners, L. jensenii, A. vaginae and G. vaginalis. The presence of those bacteria in qPCR results was interpreted. Results: Twenty-nine women were recruited from 15 May 2014 to 17 September 2014 including 19 pregnant women presenting for an antenatal ultrasound including cervical screening for preterm birth at 18-24 weeks’ gestation and 10 non-pregnant women having a baseline scan as part of the investigative workup for fertility / IVF assessment. A total of 87 iv vaginal samples were collected from the 29 patients. The condom / PreservCyt ThinPrep method appear to produce most reproducible PCR results. This method had Kappa values of 0.75, 0.50, 0.86, and 0.8 for L. iners, L. jensenii, A. vaginae, and G. vaginalis respectively. The average level of agreement between the two sample runs was 87.4%. The interclass correlation coefficient (ICC) values for this method were also relatively high 0.76, 0.52, 0.87 and 0.85 for L. iners, L. jensenii, A. vaginae and G. vaginalis respectively. Of the 21 women reviewed, prevalence L. iners: 13/16 (81.3%) pregnant women and 4/5(80.0%) non-pregnant women, L. jensenii: 9/16 (56.3%) pregnant women and 2/5(40.0%) non-pregnant women. A. vaginae: 7/16 (43.8%) pregnant women and 2/5(40%) non-pregnant women. G. vaginalis: 9/16 (56.3%) pregnant women and 1/5(20.0%) non-pregnant women. The sensitivity and specificity of the condom as a novel sampling method, when compared to the swab/PreservCyt method, were 71.4% and 60% for L. iners, 50% and 75% for L. jensenii, 66.7% and 75% for A. vaginae, and 40% and 71.4% for G. vaginalis respectively. (p>0.05). Conclusion: The novel condom / PreservCyt ThinPrep sampling method appears to have value and is worthy of further development and investigation. |
