Download I - UAB School of Optometry

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Scribe: Hunter Neill
Wednesday, November 5, 2008
Proof: Taylor Neill
Dr. Waites
Neisseria and Chlamydia
Page 1 of 4
Neisseria and Chlamydia
I. Neisseria gonorrhoeae Characteristics [S27]
a. Will not grow on typical blood agar plate
i. Must give special enriched media such as chocolate agar
1. Called chocolate agar because it’s brown and looks like chocolate
2. Neisseria are non hemolytic bacteria and therefore need the blood cells in the media on which they
grow to be lysed to be able to acquire nutrients (the lysed blood cells give chocolate agar it’s brown
color)
ii. Neisseria meningitidis will grow either on blood agar or chocolate agar, but N. gonorrhoeae usually will only
grow on chocolate agar
iii. Also like CO2, if you don’t provide CO2 they will not grow well
iv. N. gonorrhoeae has been studied extensively for how it causes disease
1. Can be transmitted primarily 2 ways: (very fastidious)
a. Mucosa to mucosa contact is necessary (cannot catch it off of a toilet seat)
b. Mother to child during the time of delivery, if the mother is infected with gonorrhoeae in the
cervix than the organism can be inoculated onto the infant as it passes through the birth
canal
v. [S28] Pili are the attachment structures that enhance attachment to the hose epithelial cells
vi. Opacity, known as opa proteins in the outer membrane of this gram negative organism, facilitate the
invasion of the bacteria into the host cell
vii. Since it’s gram negative it contains endotoxin in its cell wall
viii. Also contains peptidoglycan (pyogenic, stimulates the recruitment of the neutrophils which cause the pus
that drips out of the urethra)
ix. The fact that it can occur inside cells helps it cause disease
x. Has an IgA protease like the meningococcus
xi. Undergoes a high rate of antigenic variation, that is it changes its surface antigens and keeps our immune
system guessing
1. This is why you can get gonorrhoeae over and over again
2. Also the reason a vaccine has not been developed
xii. A lot of antibody resistance mediated by extra chromosomal plasmids as well as in the bacterial
chromosomes makes it more difficult to treat
II. N. gonorrhoeae Detection [S29]
a. In men detection is fairly easy
i. If there is a purulent [pertaining to pus] discharge from the penis, most will go to the doctor
ii. Make a gram stain of the discharge from the urethra and see the gram negative diplococci, this provides
the diagnosis because the urethra is usually sterile – it should not have white cells nor gram negative
diplococci cells present
b. In females it is more difficult, because other non-pathogenic Neisseria are present, so you must do some special
things
i. Can swab and culture the bacteria, but you must grow it on chocolate agar that contains antibiotics
(Thayer-Martin) to inhibit the commensal flora and other non pathogenic Neisseria
ii. Must be very careful with the culture because they don’t like cold temperatures, should inoculate
specimens at bed side if possible
iii. Organisms can be identified by the fact that they oxidize glucose and have a positive oxidase test
c. In most clinical labs we have advanced beyond culture as it takes a few days to get a result
i. We can now do a nucleic acid amplification test that will pick up N. gonorrheae as well as Chlamydia
trachomatis
1. This is a PCR based test, meaning that if the DNA of theses microorganisms is present in the body
fluid that you are looking at, you put this into the PCR system and the nucleic acid is amplified and
then reacted with the DNA primers for the organisms that you are seeking. If hybridization occurs,
you know the DNA of the organism is present
2. Test can be done on urine, do not have to culture form the cervix because the PCR test is so
sensitive
3. Can screen a lot of people because this is cheaper, quicker, and cheaper – this is important as most
women that have gonorrheae are unaware because little or no symptoms manifest, they may carry
the organism asymptomatically and infect male sexual partners
4. More likely cause manifestations in a man
III. N. gonorrhoeae Diseases [S30]
a. This is the discharge from the penis that you see in a male urethritis
FUN2: 11:00-12:00
Scribe: Hunter Neill
Wednesday, November 5, 2008
Proof: Taylor Neill
Dr. Waites
Neisseria and Chlamydia
Page 2 of 4
b. If you have sexual relationships with an infected person there is a 20-30% likelihood of contracting the disease
c. It does not just cause an annoyance
i. Can cause a septic arthritis in both men and women
ii. In women it can travel up through the uterus into the fallopian tubes and cause pelvic inflammatory disease
which can be severe and potentially life threatening
1. Two complications can occur from pelvic inflammatory disease:
a. Scarring in the fallopian tube which can cause infertility by blocking the fertilization of the egg
b. Scarring can also cause a fertilized ovum from making its way back to the uterus to implant,
resulting in tubal pregnancy that will eventually burst the tube. Bleeding till death can occur
iii. Transmitted by mucosal to mucosal contact, anal intercourse can lead to anal gonorrhea, oral intercourse
can lead to pharyngeal gonorrhea
iv. [S31] Opthalmia nonatorum – gonorrhea passed from mother (with active gonorrhea) to infant
1. When the infant passes through the birth canal the gonorrhea organisms can colonize the infants
eyes, conjunctiva, and eyelids causing a severe inflammatory process leading to blindness
a. Routine to put antibiotic or silver nitrate drops in infants’ eyes as mother can give birth without
being aware she has gonorrhea
b. Photo of child’s eye with gonorrhea, can destroy the neonates eye
c. Chlamydia can also produce this type of illness
IV. Neisseria gonorrhoeae Prevention [S32]
a. No vaccine exists for N. gonorrhoea
b. Condoms help
c. Education is important
d. Silver nitrate or antimicrobial drops in neonates eyes to prevent opthalmia neonatorum
V. Chlamydia trachomatis Characteristics [S34]
a. Can produce many of the same types of illnesses, but it’s a very different microorganism
b. Obligate intracellular pathogen, meaning that they cannot be cultivated in a microbiology lab using the traditional
methods
i. Cannot simply swab the bacteria onto an agar plate like traditional bacteria
ii. Must grow them inside a cell line of some sort because they do not have the ability to grow independently
of a host cell. They are completely dependent on a hose cell for their existence because they are not able
to make their own ATP, they must utilize the ATP of the host cell.
c. They are gram-negative bacteria, but do not have peptidoglycan in their cell wall and don’t gram stain.
d. Unique intarcytoplasmic growth cycle
e. They are able to grow inside the host cell because they prevent the fusion of the phagolysosome after they have
been taken
f. Photo of inclusion inside a host cell, shows how they appear inside a host cell
g. 15 different serovars of C. trachomatis
VI. Chlamydia Life Cycle [S35] ~ a three day period
a. The infectious organism that you acquire through venereal transmission in the case of C. trachomatis is called
the elementary body or small particle
b. The elementary body will enter a host cell inside a membrane bound phagolysosome where it is not killed and
allowed to replicate
c. Then it becomes metabolically active and changes into a reticulate body (RB)
d. The RB multiplies inside the cell
e. The RB then changes back into elementary bodies
f. Then the host cell lyses and releases all the elementary bodies and each of these elementary bodies can go on
and infect another host cell
g. The initiation of this cell lysis causes the inflammation, irritation and symptoms of urethritis
h. In general infection the organism attaches to the mucosal epithelium causing inflammation and discharge
i. You can get a urethritis in men and women due to Chlamydia
ii. Usually not as severe and pyrogenic as what you see in gonorrhea
iii. Diagnosed in a man by looking at a urethral smear and seeing the neutrophils but not seeing any of the
gonorrhea bacteria – this means it’s likely to be Chlamydia
VII. Chlamydia – Ocular Trachomatis [S36]:
a. Important for optometrists because it is the b. Leading cause of blindness especially in developing countries around the world
c. Caused by the same organism as the genital disease
d. It’s in inoculated in the eyes
e. Spread in crowded conditions with low socio economical status and poor hygiene
FUN2: 11:00-12:00
Scribe: Hunter Neill
Wednesday, November 5, 2008
Proof: Taylor Neill
Dr. Waites
Neisseria and Chlamydia
Page 3 of 4
f. Causes inflammation of the ocular tissues and ultimately causes fibrosis of the eye occurs due to the chronic
inflammatory process that occurs.
i. The ensuing scaring causes blindness. It causes a granulomatus type inflammation called collusion
conjunctivitis. (You can do a scraping of the conjunctiva and see the Chlamydia inside the cells there with
a giemsa stain. That’s why it’s called inclusion conjunctivitis.)
g. Methods for detecting [S37]:
i. Since it is an obligate intracellular organism it can be cultured if you use a cell line.
ii. Can take a clinical specimen (swab from the eye or genital secretions) and inoculate it into a cell culture
and then grow the cells
iii. Stain them with a monoclonal antibody using a fluorescence stain to stain for the inclusion bodies and view
under a fluorescent microscope
1. It is tedious and cumbersome and take several days
iv. Now days for the genital tract infection can do nucleic amplification or PCR based test
v. There are also some antigen detection test that are not amplified methods
1. Not recommended b/c they are not as sensitive
vi. PCR test is the way to go and includes several different tests
h. [S38] This slide shows a patient with ocular trachoma
i. (On the lower eye lid), there is the follicular keratoconjunctivitis
ii. In the early 20th century when many immigrants were coming into the United States, Trachoma was very
common because it was very common in poor people who lived in crowded condition with large families.
iii. Because it is a contagious disease, when people were coming into Ellis Island, New York they were
required to take an eye exam before being allowed to enter. If they found trachoma on their conjunctiva
they would usually deny entrance.
iv. At this time there was no antibiotic treatment.
i. Ocular Trachoma is still present in at least 400 million people, mainly in other countries
i. Optometry students may see it on their trips abroad were it is more common
j. C. trachomatis serovars (or serological variations) A, B, Ba and C are the ones that cause it
VIII. Neonatoal Infections [S39]
a. In addition to the conjunctivitis that newborn infants can get, the opthalmial neonatorum when they encounter
Chlamydia
i. If they aspirate the organisms at the time they are delivered (organisms from their mother), it can set up
pneumonitis in the lungs.
IX. Diseases in adults from Chlamydia [S40]
a. Non-gonococcal urethritis
b. Cervicitis in Women
c. And all of the same complication that occur with gonorrhea
i. These diseases often coexist. That why when a person presents with one of these conditions, they will
typically be treated for both because they are often present at the same time.
d. Many women are asymptomatic and can transmit the disease to men and not even know they have it
X. Lymphogranuloma Venerum [S41]
a. Caused by the L1, L2 and L3 serovars of C. Trachomatis
b. Not commonly transmitted in the US
c. It has different manifestation than the urethritis.
i. Picture is the groin area with bubos or swollen lymph nodes that get a granulomatis type of inflammation.
In the lymph nodes here, adenopathy here when the Chlamydia effects these lymph nodes
ii. You get Inguinal Lymphatic involvement and obstruction
d. Much less common manifestation that chlamydial urethritis and only cause by these 3 serotypes
e. It therefore get a different name Granuloma Venerum but still caused by the organism as the urethritis
XI. Prevention of C. trachomatis [S42]
a. Like with gonorrhea, there is no vaccine so there nothing you can give people to give them to keep from getting
it.
b. There is also no protective immunity so you can get it over and over and over.
c. They way you prevent it is through education and improving socio economics and hygiene (especially with the
respect to the trachomatis because that seems to be the major risk factors)
XII. Chlamydophila Psittaci [S43]
a. Here is a picture of a “Pretty Parrot”
b. C. Psittaci is sometimes called parrot fever
c. It is a disease of parrots and parakeets that can be transmitted to humans
d. If the bird get sick with chlamydophila, the bird secretions can be inhaled and cause pneumonia in humans
FUN2: 11:00-12:00
Scribe: Hunter Neill
Wednesday, November 5, 2008
Proof: Taylor Neill
Dr. Waites
Neisseria and Chlamydia
Page 4 of 4
e. Can also be transmitted through feces when cleaning as it become aerosolized and can also cause pneumonia
f. Diagnosis by collecting blood and analyzing antibodies against the C. psittaci
g. Know for a number of years, but in the mid 1980’s it became apparent that people would get respiratory
infections. Doctors would send the antibody test and would come back positive even though the patients had no
history of any exposure to birds. It was know that this C. psittaci was only transmitted through birds making the
results puzzling.
h. It became apparent that there was actually another Chlamydia involved - C. pneumoniae.
XIII. C. pneumoniae [S44]
a. The test used for the parrot fever was not specific enough to separate from this Chlamydia
b. This is the agent initially called TWAR (initials of the people who discovered it)
c. First described in the 1980’s
d. Similar life cycle (depicted on slide). The oval shaped organisms are the elementary bodies. It produces an
acute lower respiratory illness than can cause a sore throat, sinusitis, and pneumonia. It causes manifestations
that are very similar to walking pneumonia caused by mycoplasma (talk in later lecture). It is clinically
indistinguishable from mycoplasma.
e. It is a low grade pathogen and most people don’t even know that they are sick presenting with a small cough,
sinus congestion and a sore throat that goes away after a few days
f. Un-common to cause severe disease
g. There is not a good laboratory test to diagnose that is widely available. You can culture it, PCR it, or antibody
tests it, but it’s not widely diagnosed. Most people that are symptomatic with it receive antibiotic from a doctor
because they don’t know what they’ve got.
h. Recent Publicity: A chronic infection with this organism may have a connection with the development of
atherosclerotic heart disease.
(I believe the story is less important than the emphasis that idiopathic diseases may be caused by unknown, undetectable
bacterial organisms) [Idiopathic = unknown cause]
i. Helicobacter pylori – Twenty years ago people though that peptic ulcers were due to stress and poor life
styles. A gastroenterologist, Barry Marshal, was convinced it was a bacterial infection because an organism
that was isolated from stomach tissue produced a urease that buffered the stomach acid making it able to
survive. He was convinced that this caused ulcers. In order to prove it, it mixed up a “cocktail” or culture of
Helicobacter and swallowed it to show that he could get ulcers. This was a landmark for which he won the
Nobel Prize because he completely changed the way we thought about peptic ulcers. Now we treat them with
antibiotics because 80% are due to the helicobacter. It changed the mindset that previously undetectable
[bacterial] infections could cause clinically important diseases in humans.
j. In the mid 90’s when nucleic acid amplification (PCR) became available they would take people that had heart
disease due to atherosclerosis. They found that there was a significantly higher likely hood that they would
have antibodies to C. pneumoniae than people who didn’t have atherosclerosis.
k. Additional studies took atherosclerotic arteries tissues and did PCR tests on it. They found Chlamydial DNA
was found in the atherosclerotic plaque. So, there’s some evidence this is a chronic infection where people get
this infection through the respiratory tract early in life, and at some point it causes an inflammatory process in
the arteries that leads to atherosclerosis.
i. Has caused a lot of research. Problems with research occurred as testing for the Chlamydia was not
always as good as it should be
ii. It’s also because asymptomatic Chlamydia is so common that it was really hard to sort out the true
association of Chlamydia to the disease (because so many people have the positive antibody to it)
iii. Cannot say whether it is true or not.
l. Reason for the story: There have been suggestions that C. pneumoniae may have a role to play (if not a
primary role than a contributing role) in atherosclerosis.
i. There is also some suggestion that it may also be involved in the demyelinating disease, multiple
sclerosis.
m. There are many diseases that we don’t know their cause. There has always been speculation that when you
have a disease that you don’t know the cause that there is an infectious microorganism that we haven’t been
able to detect.
n. It is more widely accepted that microbes can cause various types of cancer.
[End 28:25]