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Chlamydia trachomatis infection of the genital tract or rectum ( SIGN 2009 ). Chlamydia are Gram-negative obligate intracellular pathogens, the 3 species which
 cause infection in humans are

Chlamydia trachomatis Humans are the natural host Serovars associated with endemic trachoma are A, B, Ba and C Serovars associated with STIs are D, E, F, G, H, I, J and K Lymphogranuloma venereum L1, L2 and L3  Genital chlamydia most commonly reported bacterial STI worldwide Men → affects urethra ( non-gonococcal urethritis ) ocassionally epididymitis Women →urethritis , cervicitis and pelvic inflammatory disease ( PVD ) Can also infect conjunctiva , rectum and nasopharynx Transmission -direct inoculation of infected secretions from one mucous membrane to another Infection has not ascended the upper genital tract -Uncomplicated infection    Spread to upper genital tract- PID in women
Epididymo-orchitis in men-Complicated

Epidemiology-Most common in people aged 16-25 At least 70 % of infected ♀ and 50 % of infected ♂ remain asymptomatic 2/3 of sexual partners of chlamydia + ve individuals will also be Chlamydia +ve Risk factors
○ Age < 25
○ More than 1 partner in the last year or a recent new sexual partner
○ Lack of consistent use of condoms Untreated infections may persist for > 1 yr ( 50 % cases ) About 95 % will clear spontaneously after 4 yrs. Untreated infections may persist for > 1 yr ( 50 % cases ) Most cases remain untreated – it is estimated that only about 10 % of all chlamydial cases are seen and treated in the GUM clinics ( Griffiths et al 2002 ) About 95 % will clear spontaneously after 4 yrs

what happens ? Natural h/o chlamydia infection is poorly understood Ct ( chlamydia trachomatis ) exists in two forms
○ infectious elementary body ( EB ) metabolically inactive
○ intracellular reticulate body ( RB ) which is able to replicate and multiply
Host cells take up EB which differentiates into RB and the RB will then use host energy sources and amino acids to replicate and form new EB which then infects additional cells leading to a rapid increase in number Target cells of Ct are the squamocolumnar epithelial cells of the endocervix and upper genital tract in females and the conjunctiva , urethtra and rectum in both men and women Infection mainly via penetrative sexual intercourse but organisms have been detected in the conjunctive and nasopharynx without concomittant genital infection Men → affects urethra ( non-gonococcal urethritis ) occasionally epididymitis Transmission -direct inoculation of infected secretions from one mucous membrane to another ( can be passed from an infected mother to the newborn during childbirth )

national programme –NSCP ( National Chlamydia Screening Programme ) in England aims to control chlamydia through early detection and treatment of asymptomatic infection to reduce the chances of onward transmission and complications of untreated infection , NSCP was established in 2003 and rolled out in 2008 Sexual Health in Wales Scheme monitors and implements measures from the Welsh Government in STI screening and prevention.

Lymphogranuloma venereum-Caused by L1 , L2 and L3 serotypes Outbreaks in HIV + ve ♂ pts who have sex with men Most presents with proctitis Asymptomatic infection may occur

 ↑ ed Vaginal discharge Post coital ( PCB ) or intermenstural bleeding ( IMB ) Purulent vaginal discharge Mucopurulent cervical discharge Dysuria ( sterile pyuria – may be Chlamydia ) Lower abdominal / pelvic pain Cervica motion tenderness Deep dyspareunia Cervicitis

 Dysuria Mucoid or mucopurulent urethral discharge Urethral discomfort/urethritis Epididymo-orchitis Reactive arthritis

○ 10-40 % will develop PID if not treated
○ risk ↑ es with each recurrence
○ can cause tubal factor infertility, ectopic pregnancy, chronic pelvic pain
 ADULT CONJUNCTIVITIS ( if eye exposed to secretions )
○ within 1-2 weeks after exposure
○ men > women
○ polyarthritis of wt bearing joints
 PERIHEPATITIS ( Fitz-Hugh-Curtis syndrome )
○ inflammation of hepatic capsule – RUQ pain can be referred to rt shoulder 
○ usually in ♀ with PID
○ rare
○ ↑ risk premature rupture of membranes
○ ↑ risk pre-term delivery and LBW
○ ↑ risk intrapartum pyrexia and late postpartum endometritis
○ ↑ risk post-oral PID
 Refer all ♀ to
 GUM clinic if PID suspected  Rectal infection is usually asymptomatic but anal discharge and anorectal discomfort may happen

Risks to newborn-Eye disease caused by trachoma biovar are called inclusion conjunctivitis Newborn acquires the infection during passage through an infected birth canal Starts mucopurulent conjunctivitis 7-12 days after delivery Response to erythromycin or tetracycline treatment 

 10-20 % infants may develop respiratory tract involvement 2-12 weeks after birth Presents with striking tachypnoea , characteristic paroxysmal cough, absence of fever and eosinophilia Suspect if pneumonitis develops in a newborn who has inclusion conjunctivitis

Testing-Nucleic acid amplification tests ( NAAT ) Endocervical or vulvovaginal swab First catch urine ( FCU ) Kits for self-taken VVSs or FCU available FCU ( specimen of choice ) Urethral swab Rectal swabs if indicated by history/ symptoms ( men and women ) to test for LGV ( Lymphogranuloma venerum ) HIV-positive ♂ who have sex with other ♂ Pharyngeal swabs- not done routinely NAAT samples- good for testing even few days after collection

Positive-Treat patient yourself and attend to partner notification + 
check for other STIs -Gonorrhoea , HIV, Syphilis, Hepatitis B
OR Treat patient yourself and refer to GU clinic for partner notification/screening for other STIs
OR Refer all patients to GU clinic Doxycycline 100 mg bd/7D 
( CI in pregnancy ) Azithromycin 1g PO stat single dose Erythromycin 500 mg bd for 10-14 days Ofloxacin 200 of bd/7D or 400 mg od/7 days ( CI in children and growing adults ) Pregnant-Azithromycin 1g single dose or Erythromycin 500 mg qds/7D or Erythromycin 500 mg bd/14 D or Amoxicillin 500 mg tds/7D

If uncertainty seek specialist advise Avoid sexual intercourse
 ( including oral sex ) until the person + partner (s) have completed treatment or waited 7 days after Azithromycin     Urgently refer GUM clinic if there is no response to 1st line Rx

Test of cure-Not routinely recommended if standard 1st line Rx used Consider if anything other than 1st line used Do test
○ pregnant ( ↓ efficacy of antibiotics )
○ non-compliance suspected
○ symptoms persist TOC ( swab or urine ) no earlier than 3 weeks after completion of treatment Offer- repeat testing to all people < 25 diagnosed with chlamydia 3-6 months after rx Offer repeat test > 25s who are at ↑ risk of reinfection


Advice leaflet from FPA



  1. GriffithsC,CuddiganAClinical management of chlamydia in general practice: A survey of reported practiceBMJ Sexual & Reproductive Health2002;28:149-152.
  2. Jawetz , Melnick and Adelberg’s medical microbiology Sexually Transmitted Infections in Primary Care
  3. BMJ 2010 ; 340 : c1915 Sexually transmitted diseases ; Editor , King K.Holmes et al Chlamydia uncomplicated genital
  4. CKS NHS Chlamyda – uncomplicated
  5. UK national guideline for the management of infection with Chlamydia trachomatis International Journal of STD and AIDS 2016 , Vol 27(4) 251-267 
  6. RCGP Sexually Transmitted Infections in Primary Care RCGP Sex, Drugs, HIV and Viral Hepatitis Group British Association for Sexual Health and HIV (BASHH)
    Second Edition 2013 By Dr Neil Lazaro Royal College of GPs British Association for Sexual Health and HIV
  7. Meyer, Thomas. “Diagnostic Procedures to Detect Chlamydia trachomatis Infections.” Microorganisms vol. 4,3 25. 5 Aug. 2016, doi:10.3390/microorganisms4030025
  8. UK Standards for Microbiology Investigations
    Chlamydia trachomatis infection – testing by Nucleic Acid Amplification Tests (NAAT) Issued by the Standards Unit, Microbiology Services, PHE Virology | V 37 | Issue no: 4 | Issue date: 09.01.17 | Page: 1 of 19
  9. Chlamydia Trachomatis British Society of Immunology via
  10. Mohseni M, Sung S, Takov V. Chlamydia. [Updated 2019 Dec 22]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from:
  11. Elwell, Cherilyn et al. “Chlamydia cell biology and pathogenesis.” Nature reviews. Microbiology vol. 14,6 (2016): 385-400. doi:10.1038/nrmicro.2016.30
  12. 2015 UK national guideline for the management of infection with Chlamydia trachomatis
    Nneka C Nwokolo1, Bojana Dragovic2, Sheel Patel1, CY William Tong3, Gary Barker4 and Keith Radcliffe5 International Journal of STD & AIDS 2016, Vol. 27(4) 251–267



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