20.     Chlamydia trachomatis.  

See also MCQ paper 1, question 4.

List of topics.

1. Key facts for the DRCOG.

2. Bacteriology.

3. Incidence.

4. Damage caused.

5. Signs & symptoms.

6. Tests for chlamydia.

7. Pelvic inflammatory disease & tubal damage.

8. Fitz-Hugh-Curtis syndrome.

9. Chlamydia & pregnancy.

10. Oracle & the ORACLE Children Study.

11. Neonatal infection.

12. Treatment.

13. Screening: National programme.

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Key facts for the DRCOG.

Chlamydia trachomatis is the commonest sexually transmitted disease in the UK .

~ 10% of sexually-active young people (<25 years) are infected.

70% of infected women have no symptoms.

It can cause:

    urethritis,

    inter-menstrual bleeding,

    pelvic pain and dyspareunia.

It can cause oral and rectal symptoms, depending on ones proclivities.

50% of infected men have no symptoms.

Other sexually-transmitted infections may be present.

10 - 30% of infected women will develop pelvic inflammatory disease (PID), according to the Department of Health.

A single attack of PID is associated with a risk of sterility as high as 20%.

It also increases the risk of ectopic pregnancy and chronic pelvic pain.

~ 70% of infected mothers transfer the bug to the baby.

This can cause conjunctivitis and pneumonia.

A national screening programme  was begun in England in 2002.

Full implementation was planned for 2007.

Screening is “opportunistic” and based on a urine test.

Early results show ~ 10% +ve tests from the screening programme.

Up to 30% of treated women are soon re-infected, presumably from their partners.

Novel methods have been introduced to screen and treat partners.

Standard treatments are: azithromycin and doxycline.

The virtue of azithromycin is that it is given as a single dose.

There are stacks of other chlamydias.

EMQs may try to confuse you in their list of options by including other chlamydias. Watch out!

Chlamydia trachomatis is also the infecting organism in Lymphogranuloma venereum.

This is rare in the UK, but should be considered in cases of genital ulceration.

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C. trachomatis (C.t) is a gram negative organism.

It is categorised as a bacterium, though it is an obligate intracellular dweller.

The gonococcus is the one referred to in “b”.

It gets its name from trachoma, the commonest cause of blindness worldwide. 

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It is the commonest sexually-transmitted disease in the developed world.

In the UK about 10% of sexually-active people under 25 years of age are infected.

As there are about 5 million people in the 15-25 year age-range.

This gives an idea of the scale of what is a major endemic problem.  

~70% of infected women are symptom-free. 

Some women may get urethritis.

Pyuria but no bacterial growth on routine culture is highly suggestive.

Some get vaginal discharge.

Even with ascending disease, many women will have little by way of symptoms or signs on examination.

Some will be admitted with pelvic and abdominal pain, fever and vaginal discharge.

About 50% of infected men are symptom-free.

Some get penile discharge or dysuria.

Rarely it can cause pain from epididimytis and prostatitis.

Both sexes can have oral or anal infection with associated symptoms.

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As an obligate intracellular organism, chlamydia has to be grown in cell culture.

Hence the special transport bottles if you plan to culture it.

It grows in columnar cells, so you need to sample appropriate areas such as the endocervical canal.

It is best identified on an intra-cervical swab or a urethral swab in patients with urethral symptoms.

Identification is increasingly based on seeking its DNA, obviating the problems of culture.

You can also use urine specimens, rather than having to take swabs.

This facilitates screening in the non-symptomatic.

Several techniques such as polymerase chain reactions (PCR) allow DNA identification.

PCR is one of those very clever genetic techniques.

You take a tiny piece of DNA .

There is so little you can ' t do much with it.

The technique uses a polymerase to copy the tiny piece.

The process is repeated, with original and duplicate being copied.

This should remind you of the graph of y = x² from your days in school.

Anyway, a chain reaction is set off, resulting in loads of copies of the original tiny piece that you can do something with.

There is a nice, animated, pictorial explanation here.

Go and have a play for a few minutes!

PCR can be done on urine samples and endocervical swabs.

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Pelvic inflammatory disease is ascending infection involving the uterus, tubes etc.

It is not known how many women who have been infected will get PID.

Some studies have suggested 15%, others as many as 40%.

The Department of Health web site puts the figure at 10 - 30%.

Unfortunately, chlamydial PID is associated with a significant risk of tubal damage and infertility.

A single episode can cause sterility in up to 20%, though figures are uncertain.

The risk of ectopic pregnancy is raised.

Chronic pelvic pain can ensue.

Fitz-Hugh-Curtis syndrome (see MCQ2, question 32) is associated with C.t and the gonococcus.

It is pelvic infection complicated by peritoneal infection and specifically peri-hepatic infection with formation of fine (“violin string”) adhesions.

A similar phenomenon can involve the appendix: “peri-appendicitis”.

The peritoneal surface of the appendix is inflamed and adhesions to surrounding tissues can occur.

The main symptom is right iliac fossa pain.

Exam-setters just love it!

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Many organisms have been implicated in the aetiology of premature membrane rupture and labour.

The link has not been absolutely proved for most of them.

Apart from bacterial vaginosis – see MCQ4, question 21.

An effective prophylactic regime has not been devised.

ORACLE was a large study to look at the benefits of antibiotics in cases of:

        established pre-term, pre-labour premature rupture of the membranes (PPROM),

        and also cases of “threatened premature labour”.

It was about infection generally, not Chlamydia specifically.

If the membranes had ruptured, erythromycin was shown to:

        prolong the interval to delivery,

        and to improve the outcome for the baby.

So it has become part of labour ward protocols for PPROM.

But it did nothing useful in cases of "threatened premature labour".

Erythromycin was compared with amoxicillin + clavulanic acid "Augmentin" and found to be superior in terms of overall benefit.

Even more significant was the fact that Augmentin was associated with a higher risk of necrotising enterocolitis in the neonate.

This was called the ORACLE Children Study.

It showed an increased risk of cerebral palsy in children whose mothers:

        had “threatened” premature labour with intact membranes,

        and who were given antibiotics.

The incidence of cerebral palsy was low, but rose in both the erythromycin and Augmentin groups.

So antibiotics are a definite "No-No" for women with "threatened premature labour" but intact membranes.

Ruptured membranes are a different matter.

There was no increased risk for babies whose mothers had PPROM and were given antibiotics.

The RCOG has issued a statement saying that its 2006 guideline on PPROM is not affected.

So protocols for PPROM that include the use of erythromycin are OK.

The RCOG has also said that its 2003 Green-top guideline on neonatal Gp B streptococcal infection also remains valid.

Nice did not recommend screening for chlamydia in pregnancy in its 2008 document Antenatal Care, CG62.

The National Screening Committee's policy in 2009 was not to recommend screening in pregnancy.

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Infected mothers will pass on the infection to the baby in up to 70% of cases.

This can cause conjunctivitis, pneumonia and ear infections.  

 R U Clear, a national screening programme, was set up in England in 2002.

Full national coverage was planned for 2007, but the money was not “ring-fenced” so there have been delays.

Young people are encouraged to have annual screening.

And they should be screened if they acquire a different partner.

The screening is based on urine testing.

~10% of those tested are +ve.

The screening is “opportunistic” with various establishments being encouraged to offer screening:

    GP surgeries,

    young people’s clinics,

    family planning clinics,

    TOP clinics,

    pharmacies,

    and even schools and centres of further education.

There are local Chlamydia Screening Offices to which the +ve results are notified.

When screened, individuals will be asked how they want to be notified of results.

This can be by letter, phone call, text message or e-mail.

They will be notified of both +ve and -ve results.

Those with +ve results will be offered treatment.

Those with +ve results will be offered screening for other sexually-transmitted diseases.

We don't know the % of those found +ve on routine screening who have another STD.

The figure is thought to be relatively low.

Unlike among those attending STD clinics, where the figure has been put at 14%.

The local Chlamydia Screening Office also arranges contact tracing.

Tracing contacts and treating them is a major problem.

Men with no symptoms may be unwilling to be investigated, even if their partner has had a +ve screen.

Men don't like having their naughty bits under scrutiny in clinics!

To circumvent this problem, novel approaches have been devised, tested and found effective.

So we now have alternatives to referring a male partner to the local STD clinic.

A postal testing-kit (PTK) can be sent or a course of azithromycin.

The azithromycin is taken to the partner by the girl, which, I would guess, improves compliance.

"No hanky-panky until you have taken the pills!"

Shades of Lysistrata!

This is known as PDPM – patient-delivered partner medication.

PTK and PDPM are both more effective that standard contact tracing.

Tracing and treating contacts is a major problem.

There are obviously problems prescribing drugs for someone you have not seen.

But this if offset by the very low risks of the drug and the effectiveness of this approach.

If the partner is not dealt with, up to 30% of the women are soon re-infected.

There is also the problem of investigating the contact for other sexually-transmitted diseases.

The uptake of screening varies widely in different settings.

Family planning clinics do well and ante-natal and gynaecological clinics do particularly badly.

Even screening patients with ectopic pregnancy is poor in the hospital setting.

Ante-natal screening is done in the USA but not in the UK.

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