**4.1 Individual methods**

### *4.1.1 Cell culture*

"Cell lines for isolation of *C. trachomatis* include Mc Coy, HeLa 229 or Buffalo Green Monkey Kidney cells" [33]. Swabs are taken from different anatomical sites (endocervix, urethra, anal canal, conjunctivae) and inoculated. However, swab collection requires special collection device and transport media as culture can detect only viable organisms. "The detection rate is around 60–80%, in reference laboratories with experienced technicians" [33]. Limiting factors for culture include extended turn-around time, intensive labor requirement and difficulties in standardization. Hence cell culture is remotely used nowadays, however it has an important niche in reference laboratories and in few conditions like to monitor antibiotic susceptibility and change in virulence.

### *4.1.2 Nucleic acids amplification tests (NAATs)*

NAATs have replaced culture as the diagnostic gold standard as they have high sensitivity and specificity and are currently the standard of care in diagnosing CT infections. With introduction of dual-target assays which incorporates a 2nd target region in NAATs the detection of new variants with deletions or recombination in one of the target regions is possible. Use of coated magnetic beads for nucleic acids isolation in the pre analytical steps also enhances the diagnostic sensitivity [34]. "These bead-based extractions systems allow simultaneous testing of chlamydia and gonococci with high sensitivity and specificity, can be automated and are used in several high-output systems" [33].

#### *4.1.3 Clinical specimens required for CT testing*

NAAT can analyze any clinical material like vulvo-vaginal, anorectal, urethral, cervical, ocular swabs, first void urine (FVU), sperms or living tissues. FDA approved NAAT's are available for first void urine, urethral, vaginal and cervical swabs. For screening asymptomatic individual's noninvasive specimen like first void urine is preferred. In contrast to collection of urine for routine culture sensitivity for other organisms where mid-stream sample is preferred, for chlamydia detection first void urine is recommended as the concentration of chlamydia sharply decreases during urination. Genital swabs are preferred in women as the CT concentration is comparatively

*Chlamydia: The Secret Enemy from the Past to Present, and Future DOI: http://dx.doi.org/10.5772/intechopen.110902*

higher when compared to urine. "A study analyzing urine, vaginal and cervical swabs taken simultaneously from asymptomatic women showed that the NAAT detection rate was highest in self-collected vaginal swabs. Hence, vaginal swabs (self-collected or clinician-collected) are the recommended sample type for women. Endocervical swabs may also be used, especially when a pelvic examination is indicated" [33].

For detection of extra genital infection like conjunctivitis, pharyngeal or anorectal infections, testing of corresponding swabs or tissue samples is recommended.

#### *4.1.4 Recent developments*

Proteomics are also being deployed in CT detection with encouraging results. These results might be used to characterize antibodies specific to detect different stages of infection.

*"The Management of Chlamydia Cases in Australia (MoCCA) study is a new initiative to address gaps in chlamydia management in Australian general practice through implementing interventions shown to improve chlamydia management in specialist services. MoCCA will focus on improving retesting, partner management including patient-delivered partner therapy) and PID diagnosis" [35].*

*"Accelerated partner therapy contact tracing for people with chlamydia (LUSTRUM): a crossover cluster-randomised controlled trial results suggest that accelerated partner therapy can be safely offered as a contact tracing option and is also likely to be cost saving" [36].*
