Mycoplasma genitalium Flashcards
When was mycoplasma genitalium first isolated?
1981
Where was m. gen first cultured from?
2 urethral samples from men with NGU
Which class of organism does m gen belong?
Mollicutes
What is unique about m gen?
Smallest self-replicating bacterium
Why is it difficult to identify m gen with standard M,C &S?
lacks a cell wall = not visible by gram stain
fastidious organism = slow to culture
How long can it take to culture m gen?
weeks to months
Where in the body has m gen been detected?
genito-urinary
rectal
respiratory tract
The specialised tip-like structure of m gen enables it to do what?
ADHERE to and INVADE EPITHELIAL cells
How does m gen evade the adaptive immune system?
ability to establish INTRA-CELLULAR infection
antigenic and phase VARIATION of its surface-exposed proteins
What is the potential mechanism through which m gen causes disease of Fallopian tube?
M genitalium can be DIRECTLY TOXIC to cells resulting in CILIAL DAMAGE.
Disease resulting from host immune response
What is the prevalence of M genitalium infection in men and women?
1-2%
Who is the higher prevalence in of M genitalium - men or women?
WOMEN > Men
What are the risk factors for m gen infection?
Younger age
Non-white ethnicity
Smoking
Increasing number of sexual partners
What is the prevalence of M gen infection in STI clinic attendees?
4-38%
What is the most common co-organism isolated with m gen infection?
Chlamydia trachomatis
What other infection is there a potential association with m gen, supported by some studies in sub-Saharan Africa?
HIV transmission
What is the prevalence of m gen in men with NGU?
15-35%
What percentage of persistent or recurrent NGU m gen identified?
up to 40%
What complications is m gen associated with in females?
endometritis PID pre-term birth spontaneous abortion sexually acquired reactive arthritis
Is there an association between tubal infertility and m gen infection?
NO - an association with tubal factor infertility has not yet been demonstrated
What symptoms or signs may be present for men with m gen infection? (7)
Asymptomatic Urethral discharge Dysuria Penile irritation Urethral discomfort Urethritis Balano-posthitis (one study)
What complications is m gen associated with in the men?
Sexually acquired reactive arthritis
Epididymo-orchitis
Proctitis (possibly)
What percentage of men with m genitalium will develop symptoms?
<10%
What symptoms or signs may be present for women with m gen infection? (5)
Asymptomatic dysuria post coital bleeding cervicitis lower abdominal pain
What is the most common symptom for symptomatic women with m gen?
post coital bleeding
What signs on speculum are suggestive of m gen infection?
mucopurulent cervical dis- charge
cervical friability
elevated numbers of PMNLs on cervical sample Gram staining
When should testing for m genitalium be CONSIDERED?
signs or symptoms of mucopurulent CERVICITIS, particularly post-coital bleeding
EPIDYDIMO-ORCHITIS
sexually-acquired PROCTITIS
When is testing for m genitalium RECOMMENDED?
NGU
signs and symptoms of PID
What is the recommended specimen type for m gen testing in men?
First void urine (98-10% sensitive)
What is the recommended specimen type for m gen testing in women?
VULVOVAGINAL swab (85.7% sensitive) vs endocervical (74.3% sensitive)
What INCREASES the sensitivity of m gen testing in women?
Performing both VVS and endocervical swab
What should all m genitalium-positive specimens be tested for?
Macro- lide resistance-mediating mutations
What is the window period for testing for m gen?
no data on the incubation period the likely window period
it is likely that sensitive tests will detect early infection.
How long should patients abstain from sex following treatment for m gen?
14 days from start of treatment
What is the rate of m gen with macrolide resistance in the UK?
40%
Why is an extended course of azithromycin potentially better than a single dose?
may be less likely to select for macrolide resistance
What are the eradication rates of m gen with doxycycline as monotherapy?
30-40%
Where in the world is m gen resistant to moxifloxacin increasing?
Asia-pacific
Why is moxifloxacin NOT recommended as first line in all cases of M. genitalium?
Limited future therapeutic options
If m genitalium infection is NOT resistance to macrolide or resistance is unknown what is first line treatment?
DOXYCYCLINE 100mg BD 7 days then AZITHROMYCIN 1g STAT ten 500mg daily for 2 days
When should azithromycin be given in relation to doxycycline for m gen treatment?
azithromycin should be given immediately after doxycycline
within 2 weeks of doxycycline
most individuals will have had doxycycline as first-line treatment for uncomplicated infection, a repeat course is not necessary unless > 2 weeks since treatment
What dosing schedule is used for treatment of m gen with moxifloxacin?
Moxifloxacin 400mg OD 10 days
What is the treatment for complicated m gen infection? (includes EO, PID, proctitis)
Extended MOXIFLOXACIN 400mg Daily FOURTEEN days
What alternative regimens are there for treatment of m gen?
Doxycycline 100 mg bd for seven days*then pristi- namycin 1 g orally four times daily for ten days
Pristinamycin 1 g orally four times daily for 10 days
Doxycycline 100 mg orally twice daily for 14 days
Minocycline 100 mg orally twice daily for
14 days
What is the benefit of treatment with doxycycline prior to azithromycin for m gen?
will reduce M. genitalium load and therefore
the risk of pre-existing macrolide mutations being present
In pregnancy and breast feeding mothers what are the treatment options for m gen?
Limited options - AZITHROMYCIN can be used; monitor for GI side effects in infants
What cardiac complication can occur as a result of administering azithromycin or moxifloxacin?
Prolong QT interval
When should a patient have a test of cure following treatment for m gen?
5 weeks after treatment
