Investigation of factors affecting the presence of lactobacillus SPP. used in identification of vaginal secretion

Aim: Detection of human body fluids is necessary in forensic investigation for the reconstruction of crime scene and how the event happened. In addition to serological tests, methods based on human RNA analysis were developed for identification of body fluids and stains. The use of bacteria for the identification of body fluids was also being investigated and studies showed the promising use of vaginal specific bacteria as a way of identifying vaginal secretions. In this study, the presence of the various Lactobacillus spp. including Lactobacillus gasseri, Lactobacillus crispatus andLactobacillus jensenii were investigated in the vaginal swab samples taken from women with vaginal infections and with postmenopausal. Material and Method: Vaginal swab samples taken from 91 volunteers who came to Çukurova University Medical Faculty Balcalı Hospital Gynecology and Obstetrics Clinic between 04.04.2016 and 06.20.2016 were used. Verbal and written consents were approved from these volunteers in this study. Samples were categorized as control group (30), infection group (31) and postmenopausal (30). RNA isolation, cDNA synthesis and PCR were done respectively to 16S-23S rRNA intergenic spacer regions of the Lactobacillus spp we investigated. PCR products were run in capillary electrophoresis. Results: Chi Square test was used for statistical analysis in comparison of categorical evaluation between groups. Lactobacillus gasseri was detected in 28 of 30 cases in control group, 21 of 31 cases in infection group and 15 of 30 in postmenopausal period group. As a result of statistical analysis, a significant reduction in detection rate of Lactobacillus gasseri in both infection group and postmenopausal period group was detected (p<0,001). L. crispatus was detected in 29 of 30 cases in control group, 26 of 31 cases in infection group and 16 of 30 cases in postmenopausal period group. Statistical analysis showed that a significant reduction in detection rate of Lactobacillus spp. we investigated in postmenopausal period group in comparison with control group and infection group (p<0,001). Lactobacillus jensenii was detected in only 15 of 30 cases in control group, 14 of 31 cases in infection group and only 2 of 30 in postmenopausal period group. Statistically significant reduction was found in detection rate of Lactobacillus spp. we investigated in postmenopausal period group in comparison with control group and infection group (p<0,001). Conclusion: It is thought that the negative results cannot be used to exclude the presence of vaginal secretion because of undetected any of Lactobacillus spp in 12.9% of infection diagnosed samples and 46.6% of postmenopausal period cases. However, positive results may be valuable especially because of no serological methods have been found in identification of vaginal secretion until now. Key Words: Sexual assault, Lactobacillus,RNA, Vaginal secretion, Body fluid identification