The presence of dsRNA virus in Trichomonas vaginalis isolates from symptomatic and asymptomatic Indian women and its correlation with in vitro metronidazole sensitivity.

ABSTRACT

Purpose: Trichomonas vaginalis, a protozoan parasite, is the causative agent of human trichomoniasis, the most common non-viral sexually transmitted disease. The infection encompasses from a complete asymptomatic presentation to severe sequelae; yet, the virulence markers have been poorly understood. It is suggested that the presence of Trichomonas vaginalis virus (TVV) in T. vaginalis may have an impact on its virulence, and its relatedness to in vitro metronidazole resistance has been reported. The aim of the study was to assess the presence of TVV in fresh and Long -Term Cultivated ( LTC) maintained T. vaginalis isolates from symptomatic (S) and asymptomatic (AS) Indian women and its relatedness, if any, with symptomatology and in vitro drug sensitivity. Materials and Methods: One thousand women (537 S and 463 AS) were screened for the presence of T. vaginalis by wet smear and culture examination of vaginal swab and urine sample. Fresh and LTC (6 months-2 years) maintained 15 isolates each from 15 S and 15 AS women were subjected to agarose gel electrophoresis following total cellular RNA extraction to evaluate the presence of double stranded (ds) RNA viral infection. The susceptibility of isolates to metronidazole was determined in vitro. Results: On agarose gel electrophoresis, three bands (5.5, 2.5 and 1.5 kb) were observed in all the 30 fresh isolates from 15 S and 15 AS women and only in 7 LTC isolates from 3 S and 4 AS women. All the fresh isolates harbouring TVV were found to be sensitive to metronidazole in vitro irrespective of the symptomatology of subjects, and out of seven LTC isolates harbouring TVV, six were sensitive to metronidazole and one showed borderline resistance. Conclusions: The results suggest that the presence of TVV alone may not be a virulence marker and loss of TVV on LTC appears to be related to drug resistance. The T. vaginalis Indian isolates are sensitive to metronidazole.