Mycoplasma phathogensity

1. Eldeain university
Faculty of medical laboratory
By the end of this lecture student
must be able to understand
mycoplasma, pathogenisity, clinical
findings ,lab diagnosis and
treatment

2. Mycoplasma
Mycoplasma belong to the class
mollicates they are smallest free living
organisms like bacteria they contain no
nucleus but they contain DNA and RNA

3. unlike most bacteria they have no cell wall
,lack fixed shape or size and also lack gram
stain reaction and lack susceptibility to beta
lactoms
mycoplasma causes serious disease in many
animals species

4. mycoplasma are commonly opportunistic organisms
include
M pneumoniae
M genitalium
M hominis

5. Mycoplasma pneumoniae
Causes atypical pneumonia
Importent properties
many are as small as o.3 um in
diameter
stain poorly with gram stain
antibiotics that inhibit cell wall
(peptidoglycan)synthesis are
ineffective

6. their outer surface is aflexible cell
membrane
it's the only bacterial membrane that
contains cholesterol
mycoplasma can grown in the laboratory
on artificial media but they have complex
nutritional requirements including several
lipids
they grew slowly and require at least 1
week to form avisible colony

7. pathogenisity and
epidemiology
M pneumoniae a pathogen only
humans it's transmitted by respiratory
droplets
in lung the organisms is rod shaped,
with a tapered tip that contains
specific proteins that serve as the
point of attachment to the respiratory
epithelium
the respiratory mucosa is not invade
but ciliary motion is inhibited and
necrosis of the epithelium occurs

8. the mechanism by which M pneumoniae causes
inflammation is uncertain it does produce
hydrogen peroxide, which contributes to the
damage to the respiratory tract cells.
M pneumoniae has only one stereotype and is
antigenically distinct from other species of
mycoplasma
immunity is incomplete and second episodes of
disease can occur.

9. during M pneumoniae infection
autoantibodies are produced against red cells
(cold agglutinins) and brain, lung and liver cells,
these antibodies may be involved in some of
the extrapulmonary manifestations
M Pneumoniae infection occur worldwide with
an increased incidence in winter

10. Clinical findings
The onset of mycoplasma pneumonia is
gradual usually beginning with
nonproductive cough ,sore throat or
earache, small amounts of whitish,
nonbloody sputum are produced
constitutional symptoms of fever, headache,
malaise and myalgias are produced

11. Lab diagnosis
diagnosis is usually not made by culturing
septum samples it take at least 1 week for
colonies to appear on special media
culture on regular media reveals only normal
flora
PCR assay that detect M pneumoniae specific
DNA in sputum or in respiratory secretions is
the best diagnostic procedure

12. Serologic testing for the presence
of antibodies in the patient serum
may also be useful
A cold agglutinin titer of 1:128 or
higher is indicative of recent
infections

13. Treatment
the treatment of choice is either a macroliae such as
erythromycin or azithromycin or tetracycline such as
doxycycline
the fluoroquinolones levofloxacin is also effective
these drugs can shorten the duration of symptoms
penicillins and cephalosporins are inactive

14. Other mycoplasma
M hominis has been implicated as an
infrequent cause of pelvic inflammatory
disease
M genitalium causes urethritis predominantly
in men ,it's estimated to cause approximately
20% of nongonococcal urethritis
infection in women are typically
asymptomatic but cervicitis may occur
DNA based laboratory test is available
,azithromycin can be used
totreatssymptomatic infection

15. Prepared by:
Ibrahim khlil Ahmed Mohammed
Hussein Mohammed abdallah
Makey Adam abdallah abdrahman
Ismail Mohammed abdlrahman
Lehman Mohammed Adam
Hawa Hassan Mohammed
Mustafa Adam rukza hassan