**6. Important challenges: Prevention, diagnosis, and treatment of chlamydial infections**

The widespread incidence and prevalence of sexually transmitted infections, especially among young population, made them a priority public-health concern worldwide. Screening, control programmes, and education in sexual behavioral aspects and contraception are fundamental for the prevention of chlamydial infections and their long-term sequelae, mainly PID and tubal infertility.

Routine screening allows the identification of asymptomatic carriers of CT and contributes to the early detection of chlamydial infections. Appropriated diagnostic services are required to obtain reliable results. The most confident tests for the detection of CT involve nucleid acid amplification techniques that are not available in all laboratories, especially in third-world countries. Nucleic acid amplification tests are more sensitive than culture or antigen tests. Improvement in molecular diagnostics will lead to improvement in treatment and prevention of damage to reproductive tissues. It has been shown that screening is cost-effective even in low prevalence populations, due to the high costs of treatment of complications resulting from undiagnosed and untreated chlamydial infections [130]. The implement of additional targeted screening of women at risk will contribute to reduce the CT-associated infertility.

Additionally, clinicians should be aware about the latest therapeutic management of chlamy‐ dial cervicitis and PID. Different antibiotics such as azithromycin, doxycycline, ofloxacin, erythromycin, and amoxicillin may be useful for treating genital chlamydial infections [131]. The antibiotic selection depends on the characteristics of the drug itself like pharmacokinetics, half-life, and bioavailability, concentration in mucous membranes and genital tissues, devel‐ opment of gastrointestinal tract side effects, safe use in pregnancy, as well as, the characteristics of the host and the clinical course of chlamydial infection. The effectiveness of therapy relies on timely treating sex partners and to abstain from sexual intercourse until completing the whole antibiotic scheme.

Unceasing efforts are conducted for the development of a chlamydial vaccine. Nevertheless, until now, no effective chlamydial vaccines are available. The knowledge of bacterial factors involved in pathogenicity will help in addressing optimal vaccine design that prevents not only chlamydial infection but also progression to infertility.
