**9. Laboratory diagnosis**

**Culture:** Conjunctival scrapings are taken from the upper tarsal conjunctiva, where inclusion bodies are most common. Conjunctival scrapings taken are inoculated into McCoy cell cultures. Usually, McCoy cell cultures were treated with cycloheximide. The adequate number of viable infectious particles and the application of the centrifugation method increase reproduction. Diagnosis can be made by detecting inclusion bodies by one of the staining methods with fluorescently labeled antibodies against Giemsa, iodine, or chlamydia antigens (LPS or MOMP) after 48–72 hours of incubation of the first passage. Detection by staining with MOMPspecific antibodies is highly specific. The disadvantages of the culture method are the need for a long time, the high workload, and the difficulties in standardization. However, some reference laboratories require a culture method to monitor antibiotic susceptibility or when a highly specific test, such as suspected sexual assault, is required [10, 11]. If cultures are to be cultivated from the samples within 24 hours, they can be kept at +4°C. If it is to be kept for a longer period of time, it should be stored frozen at −70°C. The specificity of the culture is 100% and the sensitivity is below 100% under appropriate conditions. In legal cases, the infectious agent should be determined by culture [17].

**Morphological detection of inclusions:** In the presence of a large number of chlamydial inclusion bodies, a preliminary diagnosis can be made if the preparations are stained with the Giemsa or Gimenez methods. Inclusions are found in the cytoplasm of epithelial cells, usually in the perinuclear space. The incidence of inclusions in preparations prepared from specimens is the highest in neonatal conjunctivitis, lower in inclusion conjunctivitis and trachoma in adults, and rare in urethritis and cervicitis. Detection of inclusions is a rarely used method in diagnosis. Difficulty in the application, low sensitivity, and specificity are the reasons for not using it [18].

**Serology:** Among the diagnostic methods other than culture, immunofluorescence and enzyme-based immunological methods (enzyme immunoassay, EIA) are the main ones [18]. Both group antibodies and serovar-specific antibodies are

*The Laboratory Diagnosis of* Chlamydia *Infections DOI: http://dx.doi.org/10.5772/intechopen.110464*

frequently found in the serum and eye secretions of infected patients. Antibodies formed against the cell wall structure of the organism are detected. The microimmunofluorescence method is a sensitive method for measuring antichlamydial antibodies [11].

**Molecular methods:** Polymerase chain reaction (PCR) and other molecular diagnostic methods are not widely used in the diagnosis of trachoma. In developing countries where trachoma is endemic, there are insufficient resources to perform PCR or other molecular tests. In developed countries, which have the opportunity to apply the tests, trachoma is rare and tests are not needed. These methods are generally used in research studies on trachoma [11].

**Treatment and prevention:** The primary source in endemic areas is children with ocular infections. Transmission occurs between infected children and their caregivers by hand-eye contact and by the feet of black flies. Hygiene rules such as facial cleaning and reducing flying insects are important in protection [11].

Azithromycin is used in the mass treatment of endemic trachoma. After 6–12 months of treatment, clinical manifestations are greatly reduced. It has replaced erythromycin and doxycycline. Topical therapy is of little value [19].

The World Health Organization initiated the S-A-F-E program to eliminate or reduce trachoma (Surgery-Azithromycin-Face-Environmental). It is a program that covers the treatment of trachoma with surgery and azithromycin, facial cleaning, and environmental cleaning by reducing black flies [11].
