Chlamydia Trachomatis Infection in Asymptomtic Pregnant Women in North India and Utility of Pooled Urine Samples for Screening

Background: Urogenital infections by C. trachomatis (CT) are the most prevalent STD. In women, infections are mostly asymptomatic (70-80%) and thus remain undiagnosed but have potential long-term complications. The aim of this study was to screen asymptomatic pregnant  women for  C. trachomatis infection and whether pooling of non invasive urine is effective for screening this  infection.

Methods: First catch urine samples were collected from 1000 asymptomatic pregnant women having gestational age less than 24 weeks attending the Antenatal Clinic  at PGIMER, Chandigarh from July 2010 to June 2012. The pooled urine samples (5x 200 pooled specimen) were tested for presence of CT by Amplicor CT PCR kit (Roche Diagnostic System) and positive results were further tested separately on each urine sample.  Direct fluroscent antibody test (DFA) assay was used on those urine specimen which were positive by PCR to confirm the results.

Results: Overall C. trachomatis infection tested by both PCR and DFA was present in 1.6% (16/1000) women and the mean age was 25.8 years. A total of 200 pools of urine samples were  tested and  20 pools were positive for CT. When these pools were  tested individually, atleast  20 (10%) samples were positive for CT by PCR  but 4 samples were negative by  DFA. Pooling saved 72% of reagent costs in our study. The sensitivity and specificity of diagnosis were not much  affected by pooling strategy.

 

Conclusions: C. trachomatis infection appears to be relatively low  in women delivering in this tertiary care hospital in India as compared to other  international studies including pregnant women. In this resource-limited setting, the use of pooling to detect C. trachomatis by PCR proved to be a simple, accurate, and cost-effective procedure compared to individual testing.