A pilot study to determine Neisseria gonorrhoeae-Chlamydia trachomatis coinfection rates in symptomatic patients attending STI Clinics, New Delhi, India.

BACKGROUND: Neisseria gonorrhoeae and Chlamydia trachomatis are the two most prevalent bacterial sexually transmitted infections. For over two decades, treatment guidelines have recommended empirical co-treatment for N.gonorrhoeae and C.trachomatis as symptoms overlap and co-infection is common. Studies from India estimating the same are limited and mostly based on conventional techniques. AIM AND OBJECTIVE: The aim of this study was to determine the frequency of N.gonorrhoeae and C.trachomatis coinfection using nucleic acid amplification tests. Further, we assessed the utility of pus cell estimation in Gram stained smears as a screening tool for inclusion of samples for molecular diagnosis. METHODS: This was a prospective study conducted at two tertiary care hospitals; 100 patients (55 females and 45 males) with genitourinary discharge attending STI clinics were recruited, and endocervical or urethral swabs were collected. PCRs for N.gonorrhoeae and C.trachomatis were put up. In addition, microscopy and culture for gonococcus was performed followed by antimicrobial susceptibility testing. Statistical analysis was performed using the SPSS 16 software. RESULTS: N.gonorrhoeae infection was more common than C.trachomatis. A total of 14 patients were positive by PCR (9 males and 5 females) for gonococcus. However, culture was positive only in 8 male patients. PCR for C.trachomatis was positive in 9 (4 males and 5 females) and the co-infection rate was 5%. The sensitivity and negative predictive value of pus cell estimation was 100% for males and 64% and 94.6% respectively for females. All isolates were susceptible to extended spectrum cephalosporins and azithromycin. LIMITATION: The sample size of the study was small. CONCLUSION: Frequency of N.gonorrhoeae/C.trachomatis coinfection in symptomatic STI patients is low. Coinfection is considerably overestimated and necessary confirmation of etiological diagnosis could reduce widespread empirical administration of broad-spectrum antibiotics.

A pilot study for diagnosis of genital Chlamydia trachomatis infections by polymerase chain reaction among symptomatic Indian women.

BACKGROUND: Chlamydia trachomatis is the most common bacterial etiology of sexually transmitted infection. AIM: A pilot study was designed using PCR for amplification and detection of a specific 517 bp sequence of the common endogenous plasmid of C. trachomatis from clinical swab specimens obtained from symptomatic female patients attending STD clinics of AIIMS and Regional STD Teaching, Training & Research Center, Safdarjang Hospital, New Delhi. METHODS: 97 patients were recruited in the study, and endocervical swabs were collected following standard procedures. The samples were analyzed by PCR and direct fluorescence antibody (DFA) for detection of C. trachomatis, and the sensitivity, specificity, PPV and NPV of PCR were calculated taking DFA as gold standard. RESULTS: Out of 97 samples tested, 9 were positive for C. trachomatis by PCR. 1 PCR positive patient was negative by DFA although a total of 11 patients were positive by DFA. The sensitivity, specificity, PPV and NPV of PCR with reference to DFA was 72.73%, 98.84%, 88.89% and 96.59%, respectively. This PCR had high specificity and NPV for detection of C.trachomatis. CONCLUSIONS: In light of the introduction of enhanced syndromic approach, which involves the use of laboratory techniques (wherever possible) to confirm clinical diagnosis, a diagnostic PCR with high specificity and NPV is particularly valuable for determination of etiological diagnosis and hence contribute to judicious use of antimicrobials in the community.