Transcript M. pneumoniae

Microbiology 2011
May 13, 2011
Yu Chun-Keung DVM, PhD
Chapter 42
Treponema, Borrelia, and
Leptospira
Chapter 43
Mycoplasma and Ureaplasma
Chapter 42
Treponema, Borrelia, and Leptospira
疏螺旋體
密螺旋體
鉤端螺旋體
Spirochete 螺旋菌目 : 細長、彎曲、有運動力的細菌
Order Spirochaetales Human disease
Treponema 密螺旋體
Borrelia 疏螺旋體
Etiologic agent
梅毒 Syphilis
貝傑 Bejel
T. pallidum
T. endemicum
斑病 Yaws
莓疹病 Pinta
T. pertenue
T. carateum
B. recurrentis
回歸熱
Relapsing fever
萊姆氏病
Lyme disease
Leptospira 鈎端螺旋體 Leptospirosis
鈎端螺旋體症
B. burgdorferi
L. interrogans
T. pallidum
Strict human pathogen, experimental
syphilis only in rabbits, cannot grown in
cell-free cultures
Syphilis (梅毒), sexually transmitted
disease
Syphilis : syn - together,
philis - love
T. pallidum
Virulence factors:



Outer membrane protein
for adherence,
Hyaluronidase for
infiltration,
Six axialperivascular
filaments (中軸纖維)
Coated with fibronection for protection against
phagocytosis
Immune response to infection: tissue destruction
Clinical course
Primary phase: papule (丘疹), hard chancre (硬
性下疳, painless ulcer) at site of inoculation,
lymphadenopathy, endarteritis and periarteritis,
heal spontaneously within 2 months, highly
infectious, Ab(-).
Secondary phase: flu-like syndrome, generalized
skin rash and condylomas (扁平濕疣), meningitis,
hepatitis, etc; subside spontaneously week to
month, highly infectious, Ab(+).
Latent: 2 or 3-10 yr, no clinical sign, noninfectious.
Clinical course
Late (tertiary) phase: all tissues may be
involved, cardiovascular lesions
(aneurysm主動脈瘤 80-85%), CNS
degeneration (5-10%), granulomatous
lesions (gummas, 梅毒腫) in skin, bone
and liver.
30% of cases completely cure after 1st or
2nd phase; another 30%, latent, serologic
test (+); remainder, progress to tertiary
stage.
Congenital syphilis
Treponemas invade fetus at the fifth
month of gestation
Causes abortion, stillbirth, or death
soon after delivery
Congenital abnormality: interstitial
keratitis, Hutchinson's teeth, saddle
nose, and eighth nerve deafness
Epidemiology
Worldwide; in USA Neisseria gonorrhoeae >
Chlamydia > Syphilis
Extremely sensitive to drying or disinfectants,
cannot be spread through contact with
inanimate objects
Not highly contagious, 30% change of infection
after a single sexual contact
Can be acquired congenitally or by transfusion;
bacteremia can persist for > 8 years
Incidence of late syphilis has markedly
decreased, primary and secondary syphilis
remain high
Diagnosis of syphilis
Direct detection of
spirochetes :
Darkfield microscopy
(motile bugs + experience
+ prompt examination)
Silver stain
Culture : not used
Serology: non-specific
and specific tests
Non-treponemal tests
Antigen: cardiolipin (beef heart) +
lecithin + cholesterol
Detect nonspecific antibody (Reagin): a
mixture of IgM & IgG direct against some
normal tissue antigens
VDRL (Venereal Disease Research
Laboratory) test for serum and CSF
samples
Advantage of VDRL:
cheap, easy to perform
quantitative, screen test
monitor disease course
trace theraputic effect, become “-”
in 6-18 m after effective treatment.
Disadvantage of VDRL
Transient false positive: acute febrile
disease, vaccination, pregnant women
Long-term false positive: chronic
autoimmune diseases, liver diseases
False negative: progressive tertiary
syphilis
Treponemal tests
Antigen: T. pallidium
Detect specific antibody to T. pallidium
(1) Fluorescent treponemal antibody (FTA) test
Killed organism + patient's serum + labeled anti-human Ig
= fluorescence “+” if Ab present
(2) Micro-hemagglutination for T. pallidum
(MHA-TP) test
(RBC + treponemas) + patient's serum
= “clumps” if Ab present
Treponemal tests
Confirmative tests for syphilis
Influenced less by therapy
False positive: autoimmune diseases
Positive serologic test in infants: mean
passive transfer of antibody OR
congenital infection
Re-test 6 months later
T/P/C
Penicillin: especially for
neurosyphilis for pregnant women
Tetracycline, doxycyline
No vaccine, safe sex
Other Treponemes –
cause
Nonvenereal treponemal
diseases
Bejel (endemic syphilis)
Yaws
Pinta
Bejel (endemic syphilis)
T. pallidum subsp
endemicum
A highly infectious skin
lesion, gummas of skin,
bones, and nasopharynx
Occur among children in
Africa, Asia, and
Australia.
Person-to-person,
contaminated eating
utensil
Yaws
T. pallidum subsp pertenue
A chronic skin disease
among children; destructive
lesions of skin, lymph nodes,
bones
Tropical areas of South
America, Central Africa,
Southeast Asia
Person-to-person, direct
contact
Nodules on the elbow
resulting from a Treponema
pertenue bacterial infection.
The Free Dictionary
Pinta
T. pallidum subsp carateum
A skin disease causing unsightly
pigment changes
Central and South America
Person-to-person, direct contact
Chapter 42
Treponema, Borrelia, and Leptospira
Borrelia recurrentis
Relapsing fever (回歸熱)
Borrelia burgdorferi
Lyme disease (萊姆病)
Relapsing fever (回歸熱 )
A bloodstream infection producing 3 to 10
recurrence of febrile and afebrile cycles.
Incubation period about 1 week
Bacteremic phase (release endotoxin)


3-7 days - fever, chills, muscle aches,
headache, splenomegaly, hepatomegaly
The bacteria are rapidly removed by specific
antibody (agglutination and complementmediated lysis)
Afebrile period


1 week
Antigenic variation - alter serotype-specific outer
envelope proteins through gene rearrangement
Relapse
Borrelia recurrentis : epidemic relapsing fever

Human body louse (no transovarian transmission),
short lifespan
Single relapse, more severe, mortality 4%-40%
Borrelia spp : endemic relapsing fever

Soft ticks (transovarian transmission), long lifespan


Repeated relapse, mortality <5%
體蝨
軟蜱
硬蜱
Lab diagnosis
Human blood → blood smear →
Giemsas or Wright stain → Borellia are
large enough to be detected by
microscope
Human blood → inject into to the
abdomen of laboratory mouse →
mouse blood → smear → stain →
Detect Borellia
Lyme disease
(萊姆病)
It is caused by
spirochete Borrelia
burgdorferi
It is transmitted to
humans by the bite of a
hard-shelled tick
(Ixodes).
Reservoir – rodents,
deer, ticks (transovarian
transmission)
Kenneth Todar University of Wisconsin-Madison
Department of Bacteriology
Disease stages of Lyme disease
Initial stage
Incubation period 3-30
days
Erythema chronicum
migrans (游走性紅斑 )
develop at site of tick
bite
Flu-like illness – malaise,
severe fastigue,
headache, fever, chill
Lymphadenopathy, >4
weeks
Late stage
80% patients develop late
manifestation (if untreated)
First phase – neurologic symptoms
(meningitis, encephalitis …), cardiac
dysfunction
Second phase - arthralgia and
arthritis
Low numbers of organisms present
in skin lesion, immunopathology (?)
Sensitivity of Diagnostic Tests
for Borrelia Infections
Test Sensitivity
Test
Relapsing fever
Lyme disease
Microscopy
Good
Poor
Culture
Poor
Poor
Serology
* IFA, ELISA
Not available
confirmatory tests*
Treatment
Relapsing fever: Tetracycline,
Erythromycin
Lyme disease: doxycycline
Chapter 42
Treponema, Borrelia, and Leptospira
Leptospira
Leptospira interrogans (問號型鉤端螺旋體)
218 serovars; shaped like a question mark;
pathogenic for wild and domestic animals
and humans
Leptospira biflexa
63 serovars; twice bent, a free-living
saprophyte, not associated with disease
Grown in medium with rabbit serum
or bovine serum albumin (neither
treponema nor borrelia can)
Natural reservoir: rodents (rats),
farm animals
Colonize the renal tubules and
shed in urine
Streams, standing water, moist soil –
source of infection, survive > 6 weeks
An zoonotic disease
Recreational exposure, occupational
exposure, flood; no person-to-person
spread
Penetrate intact mucous membranes or
skin through cuts or abrasions, through
blood stream, spread to all tissues
Multiply rapidly and damage
endothelium of small blood vessels
Leptospirosis
Mild leptospirosis (90% of cases)
Severe leptospirosis (Weil’s disease)
Acute stage (septicemic phase) : the first week
after organisms enter the bloodstream, leptospira
can be cultured from the blood and cerebrospinal
fluid.
A short asymptomatic period
Chronic stage (immune phase) : leptospirae are
found only in the urine.
Jaundice (organisms invade liver); nephritis
(organisms invade kidney). Death results from
kidney failure.
Diagnostic tests for Leptospirosis
Test
Method
Sensitivity
Microscopy Gram stain
Insensitivity
Darkfield
Insensitivity
FA
Insensitivity
Culture
Blood
“+” during 1st wk
CSF
“+” during 1st or 2nd wk
Urine
“+” after 1st wk
Serology Microagglu.*
Sensitive, specific
*patient’s serum to agglutinate live leptospira
(reference laboratory test)
T/P/C
Penicillin or ampicillin i.v. for severe
cases
Doxycycline, ampicillin p.o. for less
severe cases
Doxycycline for prophylaxatic
Vaccination of livestocks and pets
Rodent control
Wash Those Soda Cans
This incident happened recently in North Texas.
On Sunday, a woman went boating taking with her some cans
of coke which she put into the refrigerator of the boat. On
Monday she became ill and was taken to the hospital and
placed in the Intensive Care Unit. She died on Wednesday.
The autopsy concluded she died of Leptospirosis. This was
traced to the can of coke she drank from, not using a glass.
Tests showed that the can was infected by dried rat urine and
hence the disease Leptospirosis. Rat urine contains toxic and
deathly substances. It is highly recommended to thoroughly
wash the upper part of soda cans before drinking out of them.
The cans are typically stocked in warehouses and transported
straight to the shops without being cleaned.
A study at NYCU showed that the tops of soda cans are more
contaminated than public toilets (i.e.).. full of germs and
bacteria. So wash them with water before putting them to the
mouth to avoid any kind of fatal accident.
Chapter 43
Mycoplasma and Ureaplasma
200 species; 16 colonize humans and 5
associated with diseases
Mycoplasma (黴漿菌)
M. pneumoniae
M. hominis
M. genitalium
Ureaplasma (尿漿菌)
U. urealyticum
Smallest (0.1-0.3
m) and simplest
free-living bacteria
(about twice the
genome size of
certain large viruses)
Small, fried-egg-like
colonies (except M.
pneumoniae)
Lack a cell wall

Highly pleomorphic shapes

Resistant to penicillin, cephalosporins,
vancomycin, but sensitive to tetracycline,
erythromycin.
Cell membrane contains sterols - rigid
Anaerobic (except M. pneumoniae)
Grow slowly in cell-free media, need sterols,
use glucose as a source of energy
(ureaplasmas require urea)
Epidemiology
M. pneumoniae
Strict human pathogen
Worldwide disease with no seasonal incidence
Most common in school-age children and
young adults (5-15y), but all age groups are
susceptible
Spread by respiratory droplets during coughing
episodes in close contact among classmate or
family members
U. urealyticum, M. hominis, and
M. genitalium
Infants (females) are colonized with the
agents
Carriage does not persist. Only a small
proportion of prepubertal children remains
colonized
The incidence of genital mycoplasmas
is associated with sexual activity

Sexually active men and women 15% with M.
hominis and 45-75% with Ureaplasma
Pathogenesis - M. pneumoniae
Extracellular pathogen;
infect and colonize
mucous membrane (nose,
throat, trachea, LRT).
Adheres to sialated
glycoprotein receptor (1) at the
base of cilia, (2) on surface of
RBC by means of P1 antigen.
Pathogenesis - M. pneumoniae
Causes ciliostasis, destroy cilia and
ciliated epithelial cells; breakdown
clearance activity, lead to LRT infection
and persistent cough.
M. pneumoniae contains superantigen,
can attract inflammatory cells and induce
cytokine secretion (TNF, IL-1, IL-6).
Clinical disease - M. pneumoniae
Mostly asymptomatic carriage
Cause mild URT disease (acute pharyngitis),
low-grade fever, malaise, headache, dry and
nonproductive cough, persist for > 2 weeks
Tracheobronchitis with lymphocyte and
plasma cell infiltration, and atypical (walking)
pneumonia
Secondary complication: hemolytic anemia,
arthritis, myocarditis, pericarditis, neurologic
abnormalities (e.g., meningoencephalitis)
Typical pneumonia - bacterial pneumonia
Abrupt, rigorous onset
Productive cough,
purulent sputum
High fever, chest pain,
stiffness in the neck
Chest consolidation
and rales.
Murray, et.al: Textbook of
Respiratory Medicine
Atypical (walking) pneumonia
Chronic in both onset
and recovery
Flulike symptomes generalized aches,
discomfort, headache,
chill, dry cough, lowgrade fever
Chest radiographs:
patchy bronchopneumonia, interstitial
pattern, not
pneumonia
Murray, et.al: Textbook of Respiratory
Medicine
Diseases caused by U. urealyticum and M.
genitalium and M. hominis
M. genitalium : nongonococcal urethritis
(NGU), pelvic inflammatory disease
U. urealyticum : NGU, pyelonephritis,
abortion, premature birth
M. hominis : pyelonephritis, postpartum
fever, systemic infection in
immunocompromised patients
Lab diagnosis
Culture of mycoplasmas is not routinely
attempted, and relatively insensitive

M. pneumoniae can grow in special medium
with animal serum (sterols), yeast extract
(nucleic acid), glucose, pH indicator, and
penicillin. Colonies have a “mulberry-shaped”.

M. hominis requires arginine for growth.
Colonies have a fried-egg appearance.

Ureaplasma requires urea for growth
Microscope: no cell wall, stain poorly, no
value
Serology – for M. pneumoniae only
Complement fixation test : high falsepositive rate
ELISA for detection of IgM and IgG Abs,
more sensitive; need dual serum samples
Cold agglutinins:

Non-specific IgM Abs that bind the I antigen on
human RBC at 4°C, develop in 65% of the
patients – insensitive and nonspecific.
Treatment / Prevention / Control
M. pneumoniae: erythromycin,
tetracycline (also good for chlamydia)
Ureaplasma: use erythromycin,
resistant to tetracycline
M. hominis: resistant to erythromycin
and tetracycline, use clindamycin
Avoidance or safe sex for genital
mycoplasma
No vaccine available