Draft European guideline (IUSTI/WHO) for the management of Chlamydia trachomatis infections

Authors: E. Lanjouw¹

J.M. Ossewaarde^2,3

                                   A.Stary⁴

                                    F. Boag⁵ 

Editor:  W.I. van der Meijden⁶ 
 

1 Department of Dermatology, Erasmus MC, Rotterdam, The Netherlands

2 Laboratory for Medical Microbiology, Maasstad Ziekenhuis, Rotterdam, The Netherlands

3 Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands

4       Outpatients’ Centre for Infectious Venerodermatological Diseases, Vienna, Austria

5       Chelsea Westminster hospital, London, UK

6       Department of Dermatology, Havenziekenhuis, Rotterdam, The Netherlands 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Draft guideline for Discussion 
 

Introduction to the guideline 

The last version of the IUSTI guideline for chlamydial infection was published in 2001.¹ Since then, the editorial board has decided to introduce evidence-based guidelines for all Sexually Transmitted Infections (STI), including chlamydial infections. Here we present the revised version of the guideline produced according to the IUSTI STD Guidelines Editorial Board approved protocol and an evidence-based approach. This guideline is intended to be used by any clinician having to deal with one or more aspects of Chlamydia trachomatis infections. 
 

About the procedure 

The guideline for management of C. trachomatis infections was written after a literature search in the Medline, Embase, and Cochrane databases for English-language articles published between January 1999 and December 2008. For this purpose a well established algorithm developed by the Dutch Institute for Healthcare Improvement (CBO) was used. This algorithm guarantees inclusion of most if not all major publications on this topic. The resulting database of publications was extended with searches on specific topics and existing guidelines.^1-5

The level of evidence was assigned according to table 1 and the grading of recommendations according to table 2. 

Table 1. Levels of evidence 

Table 2. Grading of recommendations 

Summary of recommendations 
 

Table 3. List of recommendations 
 

Aetiology and transmission 

C. trachomatis is an obligate intracellular bacterium that infects over 90 million people each year by sexual transmission. It is the most common bacterial sexually transmitted infection worldwide, especially infecting young adults. C. trachomatis belongs to the genus Chlamydia together with Chlamydia muridarum and Chlamydia suis. Other chlamydiae infecting human beings, Chlamydophila pneumoniae and Chlamydophila psittaci, have been classified in a separate genus.⁶ Three biovars comprising all 15 classical serovars and several additional serovars and genotypes are recognized within C. trachomatis: the trachoma biovar (serovars A-C), the urogenital biovar (serovars D-K), and the lymphogranuloma venereum (LGV) biovar (serovars L1-L3). This guideline only covers urogenital infections caused by the urogenital and the LGV biovar of C. trachomatis.

Transmission takes place by direct mucosal contact between two individuals during sexual contact or at birth. Occasionally, other ways of transmission (fomites, enemas, sex toys) may play a role, as has been suggested in the LGV proctitis epidemic. The rate of transmission between sex partners may be as high as 75%.⁷ Thus, partner notification and subsequent treatment are very important. 
 

Clinical features 

Urogenital infections in women

• Up to 90% asymptomatic
• Cervicitis
• Urethritis
• Post-coital bleeding
• Pelvic inflammatory disease (PID)

Symptoms and signs in women ^8,9

• Vaginal discharge
• Contact bleeding
• Poorly differentiated abdominal pain or lower abdominal pain
• Mucopurulent cervical discharge
• Cervical friability
• Cervical oedema
• Endocervical ulcers

Urogenital infections in men

• Up to 50% asymptomatic
• Non-gonococcal urethritis
• Epididymitis

Symptoms and signs in men ^10,11

• Burning with micturition
• ‘Penile tip irritation’
• Watery, viscous excretion (‘morning milker’)

Neonatal infections

Infants born to mothers through an infected birth canal may become colonized and develop conjunctivitis and pneumonia.¹² 

Complications in women ^13-15

• PID
• Endometritis
• Salpingitis
• Ectopic pregnancy
• Tubal factor infertility

Approximately 10 percent of women with C. trachomatis infection will develop PID if left untreated. While PID caused by Neisseria gonorrhoeae infection may be accompanied by more acute symptoms, PID caused by C. trachomatis infection is associated with a higher rate of subsequent infertility (Level III).¹⁶ Early and appropriate therapy has the potential of significantly reducing the long-term complications of PID.⁴ Other complications of C. trachomatis infection consist of reactive arthritis (or Reiter´s syndrome), perihepatitis (Fitz-Hugh-Curtis syndrome), chronic pelvic pain (women), anorectal discharge, and adult conjunctivitis. 

Lymphogranuloma venereum

• Caused by the L1-L3 serovars of C. trachomatis
• Rarely reported in developed countries before 2004
• Since 2003 outbreaks reported in the Netherlands and other developed countries in men who have sex with men (MSM).^17-19
• The main site of infection: proctum
• Symptoms:
  • Tenesmus
  • Constipation
  • Anorectal pain
  • Mucopurulent discharge
  • Diarrhoea
  • Abdominal pain

Proctitis was known for many years in MSM as the ‘gay bowel syndrome’. LGV was implicated as a causative agent as early as 1976.²⁰ Since the symptoms of LGV proctitis resemble those of Crohn’s disease, many patients have been mistakenly treated for Crohn’s disease.^21,22 In order to manage this epidemic among MSM, the need for standardized criteria and procedures as well as guidelines became obvious.^3,23 
 

Diagnosis of chlamydial infections 

Diagnostic assays:

• Nucleic acid amplification techniques (NAATs)
• Isolation in cell culture
• Enzyme immunoassays (EIA)
• Direct fluorescence assays (DFA)

Since many studies have shown the superiority of NAATs over other techniques, only NAATs detecting all known variants can be recommended (Grade A, Level I).²⁴  

Assessing performance of NAATs

In evaluating the performance of highly sensitive NAATs a perfect gold-standard could not be defined and discrepant analysis has been used to reassess the supposedly false-positive reactions of the NAATs. Discrepant analysis might introduce a bias towards a higher sensitivity than can be accounted for.²⁵ Since many studies have been published, including studies only using highly sensitive NAATs, it is not likely that this bias will lead to ill advised guidelines (Level I).²⁶ Sampling error, biological variation, local differences, and  incidence of C. trachomatis infections in populations sampled are more important determinants of performance evaluations (Level IV). 

Choice of NAAT

Different manufacturers have developed their own amplification technology platforms. Although sensitivity and specificity do vary slightly, other factors like cost, hands-on time, combined testing for other agents, degree of automation etc. play an important role in choosing a specific NAAT.²⁷ The latest versions of the NAATs of major manufacturers are all adequate (Level II). 

Diagnostic challenges

• Emergence of LGV among MSM
• Emergence of the Swedish C. trachomatis variant

Detecting LGV

LGV proctitis has always been described in textbooks, but due to a very low prevalence is not always considered in the differential diagnosis of proctitis. All NAATS will detect LGV as C. trachomatis-positive, but without designating the result as LGV positive. For this purpose, genotyping is necessary (Grade B, Level II). 

Detecting variants

Possible variants:

• Plasmid free strains
• Plasmid mutant strains

Most commercially available NAATs only detect one target, either the cryptic plasmid, the major outer membrane protein gene (MOMP), or rRNA. Thus, NAATs are prone to erroneous results in case of genetic alterations. The plasmid occurs in an average copy number of 4.0 plasmids per chromosome and is highly conserved.^28,29 Therefore, the plasmid is an attractive target for NAATs. However, NAATs based only on plasmid sequences will not detect plasmid free C. trachomatis variants. It is not clear if this constitutes a real problem since only a few reports exist on the occurrence of plasmid-free strains. Although all genes located on the plasmid are transcribed during infection, three groups reported the isolation of a strain lacking the plasmid. ^30-33 Matsumoto et al. indeed showed that plasmid-free strains can be isolated from clinical specimens using special cloning techniques and that these strains may survive.³⁴ Thus, the plasmid is not essential for survival. One group studied a series of 40 specimens from high risk patients with various nucleic acid assays and concluded that 9 specimens contained no plasmid sequences.³⁵ Further analysis comparing these specimens with C. trachomatis type strains showed they were genetically similar.³⁶ However, confirmation of these results has not been reported (Level III).

An unexpected 25% decrease in the prevalence of C. trachomatis infections triggered Ripa and Nilsson to study the cause. They reported a new variant of C. trachomatis with a 377 base pair deletion in the plasmid, exactly at the target sequence of several commercial NAATs.^37,38 Later it became clear that laboratories relying on these NAATs missed between 20% and 65% of C. trachomatis infections.³⁹ A real-time PCR assay for detection of the Swedish variant has been developed and subsequent analysis showed that this strain has to date only rarely been encountered outside of the Scandinavian countries. ⁴⁰ Laboratories need to choose a NAAT capable of detecting the Swedish variant (Grade A, Level I).

It is recommended that laboratories participate in quality assurance programs, including monitoring systems, to detect genetic variants, less common serovars and uncommon clinical presentations (Level II). 

Expert networks

Both the experience with LGV and with the Swedish variant show the added value of expert networks like ESSTI for quickly assessing new findings and for notifying professionals in Europe and the rest of the world.^18,41 It is recommended that laboratories participate in (expert) networks for timely communication about genetic variants, less common serovars, and uncommon clinical presentations (Grade B, Level II). 

Choice of specimen

Until recently different types of specimens were recommended for screening programmes and clinical settings. This is no longer the case. 

Type of specimen of first choice:

• Men:  urine
• Women: (self-collected) vaginal swab

The sensitivity of testing male urine is 85-95%.^26,42 The concordance of different NAATs is highest for symptomatic men. Also, the acceptability by men of urine specimens is generally good.⁴³ Urine should be used to diagnose chlamydial infections in men (Grade A, Level I).

For females, the sensitivity of testing urine is slightly lower than that for males: 80-90%.²⁶ Self-collected vaginal swabs provide an acceptable alternative.^44-51 Also, self-collected vaginal swabs are well accepted by women.⁵² The differences in sensitivities between tests on specimens from various sites is likely to be the result of the differences in bacterial load in these specimens.⁵³ Self-collected vaginal swabs should be used to diagnose chlamydial infections in women (Grade A, Level I).

Pap-smears provide an attractive type of specimen for epidemiological purposes using already available specimens. Although several procedures have been described to optimize performance of detection of C. trachomatis in Pap-smears, they cannot be recommended for specific screening programmes, nor for diagnostic purposes (Level II).⁵⁴

Other types of specimen

Pharyngeal and conjunctival specimens

Due to the low bacterial load NAATs are the test of choice for adult and infant pharyngeal specimens. Although the bacterial load in neonatal conjunctivitis is probably higher, NAATs still show an increase in sensitivity over non-amplification assays. NAATs have now been adequately validated for these specimens (Level II).^55-58 

Rectal specimens

Isolation in cell culture and enzyme immunoassays are not suited for rectal specimens, due to toxicity of the specimens and extensive cross-reactions, respectively.

The specificity of current commercial NAATs seems adequate, although laboratories employing these assays should recognize that specificity is less than 95% and confirmation by another assay might be appropriate (Level II).^57-59 In MSM, positive rectal specimens should be genotyped for LGV (Grade B, Level II).⁶⁰ 

Semen specimen

Up to 10% of semen specimens might contain inhibitors for NAATs. However, a good correlation exists between first void urine positivity and semen positivity.^61-63 Therefore, testing of semen specimens is not recommended (Grade B, Level II). 

Pooling of urine specimens

To reduce the workload and/or cost, laboratories might want to pool urine specimens. Depending on the prevalence calculations can be made on cost and benefits. However, female urine might contain inhibitors^64,65 that would cause false-negative results in other specimens from the pool. Therefore, in the era of automated high-throughput equipment and considering the need for unambiguous identification and tracking of specimens, as well as the need for reduction of human errors, pooling of urine cannot be recommended (Grade B, Level II). 

Sampling error

First portions of urine have a higher bacterial load than second and third portions. Thus, first- void urine should be used.⁶⁶ Voiding interval seems not to effect diagnostic performance.⁶⁷ Early morning urine does not seem to be more sensitive than urine produced at the time of visit.⁶⁸ Thus, male urines can be collected at the time of the visit (Level II).  

Hormonal levels

Hormonal levels have been suggested to influence C. trachomatis detection by NAATs.

Hormonal levels influence:

• Bacterial load (increase or decrease)
• Presence of inhibitors (increase or decrease)

Bacterial load seems to increase with time after the last menstrual bleeding, while the presence of inhibitors in urine seems to be maximal three weeks after the last menstrual bleeding.^64,69 Thus, the optimal period for taking vaginal swabs seems to be four weeks after the last menstrual bleeding (Level III).  

Inhibition

In some studies differences between NAATs have been observed, but this has not been confirmed in other studies.⁷⁰ Urine from pregnant women might contain inhibitors, as well as urine taken in the third week after menstrual bleeding.^64,65 It is likely that hormones play a role in this inhibition. Various solutions (e.g. freezing, boiling or diluting the specimens) have been suggested to deal with inhibition, but none of these is generally applicable nor generally accepted.

Another concern (competitive inhibition) is raised by the use of duplex or multiplex assays detecting more than one target. If one of the targets is present in excess, other targets may be reported false-negative.^71,72 In these cases, the use of monoplex assays is needed to achieve the desired sensitivity (Level II).  

Confirmatory testing

Several strategies have been evaluated for confirmatory testing. One could use the same specimen, a second specimen taken at the same time, or a new specimen. Also, one could repeat the original test or one could use a different test.

Using a second platform for confirmatory testing can only be implemented when the second platform is at least as sensitive as the initial platform.⁷³ After all, using a less sensitive test would reduce the overall sensitivity to the level of the least sensitive test.

For specimens with a high bacterial load all types of confirmatory testing will be positive and, therefore, confirmatory testing is unnecessary and expensive. For specimens with a low bacterial load, as can be expected in low prevalence populations or in screening programmes of asymptomatic individuals, confirmatory testing will confirm 80-90%, depending on the initial test and the confirmatory procedure. More rigorous testing shows that the assumption that non-confirmed specimens are negative is wrong. Thus, confirmatory testing of specimens with a low bacterial load does not solve the issue of true positivity and is therefore not recommended (Grade B, Level II).⁷⁴ Proficiency testing, and laboratory accreditation seem more appropriate to assure high quality of laboratory results (Level II). 
 

Serology

In general, only invasive disease will lead to antibody levels useful for diagnostic purposes.

Chlamydial serology:

• Only synthetic peptide-based EIAs show no cross-reactions
• Duration of antibody-positivity is not known
• No value in the diagnosis of uncomplicated cervicitis and urethritis⁷⁵
• Limited value in the diagnosis of ascending infections^76-78
• Limited value for infertility workup⁷⁹
• LGV: high titres (IgG and/or IgA) can be diagnostic^17,22,80,81
• Neonatal pneumonia: IgM can be diagnostic¹²

Antibody testing to C. trachomatis is only recommended for diagnosis of invasive disease, such as LGV, and neonatal pneumonia (Grade A, Level I). 
 

Quality assurance

As mentioned in the paragraph on confirmatory testing, quality assurance is important to guarantee correct test results of high quality. For blood products, a working group was convened dealing with NAAT validation and standardisation, reference standards, proficiency testing , and external assessment of laboratory performance, to assure quality of testing and safety of products across all laboratories.⁸² In general for NAATs procedures have been developed to assure quality.^83,84 Diagnostic procedures for C. trachomatis are not different from other diagnostic procedures. Performance problems can be detected, that would remain undetected following manufacturer’s instructions only.⁸⁵ Laboratories should participate in quality assurance programmes, either by their own choice or by national requirements (Grade A, Level I). 
 

Therapy 

Uncomplicated urogenital CT infections

Although the natural course of infection has not been studied in great detail, it is assumed that many infections will clear spontaneously over time.⁸⁶ Some infections may proceed into a chronic persistent state.⁸⁷ Since sequellae might be severe, treatment is recommended. Resistance, although infrequently reported to date, does occur in C. trachomatis and is associated with treatment failure.^88,89 However, susceptibility testing is not regularly available and the incidence of resistance is unknown. Thus, therapy is initiated empirically. A recent meta-analysis revealed that a single dose of azithromycin and a 7-day course of doxycycline are equally effective.⁹⁰ Alternatively, josamycin has been used with success in some countries.⁹¹

First choice treatment of uncomplicated urogenital chlamydial infection consists of one of the following (Grade A, Level I):

• Single dose of 1 g azithromycin
• Course of doxycycline, 100 mg bid for 7 days
• Course of josamycin, 500-1000 mg bid for 7 days
• Course of another macrolide in an appropriate dosage

Therapy in pregnancy

C. trachomatis infections also occur during pregnancy. Infection is associated with premature labour, preterm birth, and neonatal conjunctivitis and pneumonitis.^92,93 The choice of drugs for treatment is important because of their possible adverse effects on foetal development and pregnancy outcome. Recently, a meta-analysis comprising 587 pregnant women reported equivalent efficacy of azithromycin, erythromycin, and amoxicillin. Side-effects were however, significantly less in the azithromycin group than in the erythromycin group. There were no differences in pregnancy outcome.⁹⁴ In some studies, erythromycin is less effective than azithromycin and amoxicillin.⁹⁵ The positive effect of treatment on pregnancy outcome even suggests screening and treatment of all pregnant women.⁹⁶ In countries were the drug is available, josamycin seems safe and effective and might also be considered.^97,98 First choice treatment in pregnancy is a single dose of 1 g azithromycin. Alternative treatment is a course of amoxicillin, 4 x 500 mg for 7 days. Erythromycin is not recommended (Grade A, Level I). In high prevalence populations pregnant women should be screened for C. trachomatis infection and, if positive, receive appropriate treatment (Grade B, Level II). 

Rectal infection with LGV and non-LGV C. trachomatis

In some reports a higher failure rate of the standard single dose of azithromycin has been described. The reason for this observation is not clear.⁹⁹ A guideline for the management of rectal LGV infection has recently been published and recommends a course of doxycycline, 100 mg bid for 21 days (Grade B, Level II)³. First choice for treatment of rectal non-LGV chlamydial infection is a course of doxycycline, 100 mg bid for 7 days (Grade B, Level II). 

Therapy failure

Limited data exist on alternative therapy in case of therapy failure. A repeated course or a longer course (10-14 days) with doxycycline or a macrolide has been suggested, but evidence is lacking (Level IV). Resistance has been shown, but therapy failure might also be caused by persistence of chlamydial strains. ^88,89 An interesting suggestion is the combined use of rifampicin and a macrolide.^100-103 Further studies are needed.  
 

Concurrent STIs 

Men and women having a diagnosis of C. trachomatis infection should be offered a complete workup for other STIs. C. trachomatis infection is a risk factor for the acquisition or transmission of HIV and other STIs. Patients should be offered screening for at least hepatitis B, gonorrhoea, syphilis, and HIV (Grade A, Level I). Mycoplasma genitalium is a sexually transmitted pathogen causing clinical disease similar to C. trachomatis, including PID.^104,105 An association with long-term sequelae has not been established yet. If facilities are available, patients may be offered screening for M. genitalium as well (Level II).¹⁰⁵ 
 

Complications 

PID remains one of the most important sequelae of sexually transmitted infections (STIs), resulting in severe morbidity and acting as the economic justification for STI screening programmes. Early and appropriate therapy has the potential to significantly reduce the long-term complications of PID, and evidence-based guidelines provide advice on the management of pelvic infection, including the use of appropriate antimicrobial regimens.⁴

Several pathogens that may play a role in the aetiology of PID should be covered by empiric therapy: N. gonorrhoeae, C. trachomatis, M. genitalium, and anaerobes.^4,106 
 

Partner notification 

There is a wide difference in practicing partner notification between countries.¹⁰⁷ Besides scientific aspects, legal and privacy aspects are important. They differ from country to country. Overall, 50-80% of partners may be reached. The higher rates were associated with various enhancements to basic referral instructions, especially if patients were offered additional counselling or medication for their partners.^108,109 Expedited partner therapy or patient-delivered partner therapy might be an efficient way to treat partners, but is not always permitted by law. ^110,111 Major concerns are the unsupervised administration of prescription drugs, lack of monitoring of therapeutic effect, side-effects, and allergies, the lack of opportunity to test for C. trachomatis or other STIs, as well as the lack of onwards partner notification, and safe sex education. In the UK, one-third of the professionals is strongly opposed; it is, however, well accepted by patients and partners. ^112-114

Given the wide differences between countries, no definitive recommendation can be given. 
 

Follow-up 

NAATS cannot discriminate between live and dead microorganisms. Up until 4-6 weeks after therapy a test result may still be positive, based on remnants of microorganisms that have not been cleared by the immune system. Therefore, a test of cure is not recommended. Since a previous C. trachomatis infection is a risk factor for future STIs, a control visit after 3-12 months can be considered (Level II).^2,5 
 

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