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Clinical symptoms
alone were unreliable in predicting infections with C.
trachomatis among symptomatic men and women in India.
Need for specific and routine strategy
for the diagnosis of genital chlamydial infection among patients with
sexually transmitted diseases in India.
Joyee AG, Thyagarajan SP, Sowmya B,
Venkatesan C, Ganapathy M.
Indian Journal of Medical
Research 2003;118:152-157.
Summary:
Question
What is the usefulness of culture and antigen detection by the direct
fluorescent antibody (DFA) test for assessing the rate of C.
trachomatis infection in symptomatic patients and the feasibility of
these tests for routine adoption in the Indian setting?
Design
The rate of genital chlamydial infection was determined using culture and
antigen detection by DFA in symptomatic patients attending STD clinics in
Chennai, India, and the clinical signs and symptoms were assessed for the
prediction of C. trachomatis infection.
Participants
Eighty women clinically diagnosed with cervicitis (n=53), PID (n=22), or
infertility (n=5), and 63 men clinically diagnosed with urethritis (n=58)
or epididymitis (n=5) attending the outpatient clinic at the Institute of
Sexually Transmitted Diseases, Government General Hospital, Chennai,
India, were tested. The mean age was 29.7 years (range=19 to 50 years).
Description of Tests and Diagnostic
Standard
Three urethral and three endocervical swabs were collected from men and
women, respectively. The first swab was used to make a Gram-stained smear
and to culture for N. gonorrhoeae. Two additional swabs were
collected and used in random order for chlamydial culture and DFA. The
swab for C. trachomatis culture was placed in 2SP transport buffer
and sent to the laboratory on ice. The specimens were either cultured the
same day or frozen for 12 to 24 h before culture. Specimens were
inoculated by centrifugation into quadrupicate wells containing confluent
McCoy cells, incubated for 48 to 72 h, stained with Lugol's iodine and
fluorescein-labeled monoclonal antibodies to C. trachomatis MOMP (Chlamyset
Antigen FA, Orion Diagnostika, Finland), and examined for intracytoplasmic
inclusions and chlamydial elementary bodies. The two unstained wells were
passaged onto fresh McCoy cell monolayers. The swab for DFA was rolled
onto an immunofluorescence slide, dried, fixed, and stained using
Chlamyset Antigen FA (Orion Diagnostica) according to the manufacturer's
instructions. The pellet from specimens in culture transport medium was
also tested by DFA.
Main Outcome Measures
The results of C. trachomatis culture were compared to those of DFA,
and the results of both tests were compared with the patients' symptoms
and diagnoses.
Main Results
C. trachomatis was isolated by culture in 27 (18.9%) and DFA
detected C. trachomatis antigen in 35 (24.5%) of 143 patients. The
detection rates were not significantly different between men and women for
either test. One woman with cervicitis was positive by culture only, while
9 patients were positive by DFA only. Compared to culture, the
sensitivity, specificity, positive predictive value, and negative
predictive value of DFA was 96.3, 92.2, 74.3, and 99.1%, respectively. N.
gonorrhoeae was detected in 21 (14.7%) patients; coinfection with C.
trachomatis and N. gonorrhoeae was detected in 7 (4.9%)
patients.
As the number of polymorphonuclear cells
per high power field in the Gram-stained smears increased, the rate of
positivity for C. trachomatis also increased. C. trachomatis
infection was not significantly associated with any particular symptom.
Authors' Conclusions
Chlamydial infections could not be predicted
on the basis of clinical symptoms alone. The DFA is a rapid, technically
simple, and cost-effective test. Its performance compared to culture was
good. Although it requires subjective evaluation and interpretation, the
DFA may be a useful routine diagnostic assay for genital chlamydial
infections in the STD referral centers in India.
Source of funding:
Not given
For correspondence:
S. P. Thyagarajan, University of Madras, Chepauk, Chennai 600005, India.
E-mail address: vcoffice@unom.ac.in
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