Chlamydial infections

Introduction 

-Chlamydiae are obligate intracellular bacteria, possess both DNA and RNA, and have a cell wall similar to that of gram-negative bacteria.

-Chlamydiae that infect humans are divided into three species, Chlamydia trachomatis, Chlamydia pneumoniae, and Chlamydia psittaci

Chlamydia trachomatis: Chlamydia trachomatis infects only humans; incubation period: 1-3 weeks 

Eye infections: Conjunctivitis, trachoma (leading cause of preventable infectious blindness)

Lung infections: Pneumonia 

Genital infections: Urethritis, Lymphogranuloma venereum 

Joint infections: Reiter’s syndrome 

 Chlamydia pneumoniae: Chlamydia pneumoniae infects only humans; it can cause upper and lower respiratory infections 

Chlamydia psittaci: Chlamydia psittaci infects birds, humans and other animals; it causes psittacosis 

Symptoms & Signs 

Genital infection: Dysuria, urethritis, discharge, which is clearer and less purulent than seen with gonorrhea; Chlamydial infection is asymptomatic in 75% of females

Diagnosis 

Nucleic acid amplification test (NAAT): is the recommended test for screening asymptomatic at-risk and symptomatic individuals 

Culture: In culture, C. trachomatis forms intracytoplasmic inclusions containing glycogen, whereas C. psittaci and C. pneumoniae form inclusions that do not contain glycogen.

Serologic tests:  mainly to diagnose infections by C. psittaci and C. pneumoniae 

Treatment 

-All chlamydiae are susceptible to tetracyclines, such as doxycycline, and macrolides, such as erythromycin and azithromycin.

-Treatment should be offered to sex partners 

-Because of the high rate of coinfection with C.trachomatis and gonococci, any patient with a diagnosis of chlamydia should also be treated for gonorrhea and vice versa 

-Chlamydia urethritis: Azithromycin 1 g orally in a single dose or Doxycycline 100 mg orally twice a day for 7 days 

-The drug of choice for neonatal inclusion conjunctivitis and pneumonia caused by C. trachomatis is oral erythromycin. 

-The drug of choice for C. psittaci and C. pneumoniae infections and for lymphogranuloma venereum is a tetracycline such as doxycycline.

Prognosis 

Untreated chlamydia can cause serious complications 

Men: Epididymitis, sterility

Women: PID, ectopic pregnancy, infertility 

Prevention 

-There is no vaccine against any chlamydial disease

-Educate patients on safer sex practices.

Q.What are the tests of choice for the diagnosis of genital C.trachomatis infections? Nucleic acid amplification tests (NAATs) Q.What is the drug of choice for Chlamydia trachomatis sexually transmitted disease? Azithromycin