American Journal of Infectious Diseases 8 (1): 5-12, 2012 ISSN 1553-6203 © 2012 Science Publications Corresponding Author: Apurb Rashmi Bhengraj, MIcrobiology and Tissue Culture Division, National Institute of Pathology, Indian Council of Medical Research (ICMR), New Delhi, India 5 Study on Survival of Chlamydia trachomatis in the Presence of Antichlamydial Drugs Apurb Rashmi Bhengraj, Pragya Srivastava, Harsh Vardhan, Suraj Singh Yadav, Laishram Chandreshwor Singh and Aruna Mittal MIcrobiology and Tissue Culture Division, National Institute of Pathology, Indian Council of Medical Research (ICMR), New Delhi, India Abstract: Problem statement: Recurrent genital Chlamydia trachomatis infections due to treatment failures may results in complex sequelae leading to reproductive complexity and morbidity. It can be resulted by the heterotypic resistance with decreased drug susceptibility characteristic of the isolate. Studies are needed to understand the treatment failures and resistance characteristic of C. trachomatis. Hence, in vitro study was conducted on C. trachomatis isolate in the presence of antichlamydial drugs. Approach: Our aim was to study ygeD gene in C. trachomatis clinical isolate having decreased drug susceptibility profile and to analyze HeLa cells phenotypically upon infection in presence of antichlamydial drugs. Sequencing was done to check any mutational change (s) in ygeD gene of C. trachomatis isolate (CT-244), mRNA expression was analyzed in presence of antichlamydial drugs by Real Time RT-PCR. Transduction study was carried out in infected HeLa cells to detect changes at cellular level in presence of antichlamydial drugs by transducing with GFP/RFP-tagged proteins and analyzed by FACS. Results: A point mutation was detected in ygeD gene of C. trachomatis isolate. Further, mRNA expression level of ygeD gene was observed to be increased at 8 hpi in presence of doxycycline while in presence of azithromycin it was increased at 24 hpi. GFP-tagged plasma membrane protein expression in infected HeLa cells found to be reduced as compare to the uninfected cells. Upon infection, the RFP-tagged actin protein expression was up-regulated in comparison to the uninfected HeLa cells. No difference in expression of plasma membrane and actin protein was observed in susceptible serovar D and CT-244 isolate. Conclusion: The present study suggest that C. trachomatis isolate with decreased drug susceptibility profile may have an active efflux strategy for its survival in the presence of antichlamydial drugs and it may not affect its host cell plasma membrane or actin organization for its survival in order to resist the antichlamydial drugs. Key words: Chlamydia trachomatis, recurrent infection, antimicrobial susceptibility, antichlamydial drugs, pelvic inflammatory, chlamydial infections, decreased susceptibility, protein expression INTRODUCTION Chlamydia trachomatis an obligatory intracellular pathogen causes a spectrum of clinically important chronic inflammatory diseases of human. C. trachomatis infection is one of the most prevalent sexually transmitted diseases in the world (Gerbase et al., 1998; Beagley and Timms, 2000). In females, C. trachomatis causes cervicitis, urethritis, ectopic pregnancy, pelvic inflammatory disease, tubal factor infertility and chronic pelvic pain (Morre et al., 2000). Studies have also implicated association of C. trachomatis infection with cervical and ovarian cancer and increase in HIV infectivity (Luostarinen et al., 2004). Antibiotics have the major role in treating chlamydial infections; azithromycin and doxycycline are considered as first line drugs by the Centers for Disease control and prevention (CDC) (Workowski and Berman, 2010). Efficacy of these drugs for treatment of chlamydial infections are high, however many researchers report the problem of recurrent infections and treatment failures Wang et al. (2005). It has also been reported that in women with persistent or recurrent infections, the infection can spread upwards from the endocervix to the fallopian tubes and may result in infertility or ectopic pregnancy (Hillis et al., 1997). Recurrent C. trachomatis infections often results from failure of antibiotic therapy or from reinfection due to