Unformatted text preview: Lesson 9 :
Bacteria in the dental
Introduction to Microbiology The oral cavity is a common site for manifestations of
systemic microbial diseases. Oral lesions may be
typical of those seen elsewhere on the body, or the
lesions may be modified by the local environment. The ease of examination within the oral cavity,
however, and any site-specific features facilitates
diagnosis of the systemic condition. Bacterial Infections
I. SYPHILIS (Lues)
V. I. Syphilis
•Syphilis is a complex sexually transmitted disease (STD) caused
by the bacteria Treponema pallidum. If detected and treated,
syphilis can be cured with antibiotics. If untreated, syphilis may
linger and progress in a stepwise fashion to later stages.
•The most common way syphilis bacteria enter the body is through
mucous membranes. Once infected, a person can pass the disease
to others (is contagious) whenever a sore or a rash is present.
•Symptoms of syphilis may be unnoticed or may mimic many
other diseases. This may cause an infected person to delay seeking
medical care or may make diagnosis difficult.
•Different stages of syphilis have different symptoms. The 4
distinct stages of syphilis are referred to as primary, secondary,
latent (hidden), and tertiary (late). •Sores mainly occur on the external genitals, vagina, anus, or rectum.
Sores can also occur on the lips and in or around the mouth. The
bacteria most commonly enter the body through mucous membranes,
usually in the area around the genitals and urinary system.
•Other, rare ways syphilis can enter the body include through
openings in the skin, such as cuts and scrapes or even through wet
kisses, if the infected person has a sore on the mouth or lips.
•Syphilis may also be transmitted by using a needle previously used
by an infected person.
•Syphilis can be transmitted through a blood transfusion, but this is
very rare. •Transmission depends on direct contact with active lesions. T. pallidum enters the body through abrasions and penetrates mucous membranes, migrating to the lymphatic system. •The organism incubates for 1090 days after which a chancre develops at the site of inoculation. Syphilis (Primary stage)
•The first symptom of syphilis is a
sore called a chancre (pronounced
shanker) that is usually painless.
The sore begins at the site of
infection as a small, solid, raised
skin sore less than1 cm (0.39 in.)
•It develops into a red, usually
painless open sore with a scoopedout appearance. The sore usually
does not bleed. Oral lesions are most
commonly seen on the lips
The oral lesion presents as a
ulceration. Two or more chancres may develop at the
same time, usually in the genital area, but
sometimes on the hands, mouth, or other body
Chancres contain millions of syphilis bacteria
and are highly contagious. This primary lesion heals typically within 3 to 6 weeks.
The patient may feel that the infection is over but about 68 weeks after the appearance of the chancre, the
secondary stage begins. Syphilis (secondary stage)
Syphilis During this stage, there are cutaneous and mucous membrane lesions that contain the T. pallidum organism that appear on the lips, throat, penis, vagina and other body surfaces. begins 6-8 weeks after primary stage
malaise, headache, low-grade fever,
weight loss, general aches
mucous patches seen intraorally
heal in 2-10 weeks without scarring Mucous patch
Mucous These lesions are called mucous patches and they are distinctive for the secondary stage of syphilis. There may be additional symptoms such as headache, lowgrade fever, and enlargement of the lymph nodes. Syphilis (latent stage)
After the secondary stage, syphilis enters a latent period during which there are no clinical symptoms. The latent period marks the end of the infectious period of syphilis. During this latent stage, the bacterium is spreading throughout the body into all the tissues and organs. dormancy period of 4-7 years with no
signs and symptoms Syphilis (tertiary stage)
•The third or tertiary stage of syphilis does not begin until years after the initial infection. •Third stage of syphilis includes the most serious of all complications.
Aneurysm of the ascending aorta due to effects on vascular system (i.e. arteritis).
Granulomatous inflammation can affect the skin, mucosa, soft tissue, etc.
This zone of granulomatous inflammation, known as a gumma, presents as an
indurated, nodular, or ulcerated lesion which.on occasion may be associated with
a large amount of tissue destruction.
•During the third stage, damage can occur in any organ of the body that arise from cellmediated immunity and hypersensitivity to the treponemal organism. widespread systemic disease
cardiovascular and neurological involvement
appearance of a gumma, a painless elastic tumor
with a necrotic center
patient is no longer infectious Gumma
•The third stage of syphilis is characterized by the formation of a gumma.
•Gummas are nodular lesions characterized by a granulomatous inflammation.
•Presents as an indurated, nodular, or ulcerated lesion which on occasion may be
associated with a large amount of tissue destruction.
•Gummas may be in any organ. It develops in 15% of untreated cases within 110 years after infection.. Intraoral involvement most frequently affects the palate or tongue. When the palate is
involved, the ulceration can perforate to the nasal cavity. Syphilis (congenital)
•Syphilis can be transmitted from mother to fetus resulting in stillbirth or birth defects such as mental retardation and neurological abnormalities. •If the pregnancy occurs during the first or second stage of syphilis, a stillbirth is more likely. •If the disease is in the latent stage, congenital deformations are usually the result. •If untreated, all children born with syphilis develop
secondary and tertiary syphilis. The infected children do
not live long enough. Syphilis (congenital)
Syphilis Transmitted by mother to
Can cause developmental
High arched palate, short
Hutchinson’s Congenital syphilis
In the oral cavity, we'll see deformations in the teeth known as Hutchinson's incisors and Mulberry molars. The maxillary incisors will have a characteristic notch in the incisal edge with possibly some brown discoloration. Mulberry molars are typically seen on the maxillary and mandibular first molars and appear to be smaller than the secondary dentition and have more developmental lobes. The microorganism is easily treated with penicillin or other antibiotics during the early stages. Bacterial infections continued:
Bacterial II. Gonorrhea
Gonorrhea is a sexually transmitted
disease caused by the gram- diplococcus
Neisseria gonorrhoeae. This bacterium
adheres to the lining of the GI tract
during sex and infects the mucosal cells
lining the epithelium.
•It spreads to the urethra, cervix, rectum,
pharynx and conjunctivae.
•N. gonorrhea is readily killed by drying
and exposure to metals and cannot be
transmitted by inanimate objects because
of its susceptibility to desiccation. It's
usually a self-limiting disease, but both
sexes can have widespread infection to the
GU tract and other parts of the body. Picture of Gonorrhea virus •Orally, gonorrhea is sometimes seen in the newborn due to infection as the
child travels through the birth canal; others through autoinoculation and in
adults through oro-genital sexual relations •In the mouth and pharynx one can find, after 1 to 3 days of
incubation, a flu-like stomatitis or pharyngitis, with lemon yellow
colored pseudomembranous exudate present. Secretions, as well as
bleeding, are also present in the gingival. The disease may pass
inadvertently in the mouth and pharynx Most woman remain asymptomatic carriers of
the disease but spread of the disease can cause
PID, ectopic pregnancies and chronic infection
of the fallopian tubes.
The incubation period is less than a week and
damage to any organs or body structures
usually heals with scarring.
Antibiotics like penicillin are the drug of
choice for gonorrhea although some resistant
strains may require higher strength drugs like
tetracycline, cephalosporins or streptomycin. Incubation period less than a week
Transmitted by mucous membrane direct
Can cause oral complications (red inflamed
mucosa, erosive ulcers, pharyngitis)
Treated with antibiotics III. Tuberculosis
III. M. tuberculosis is a highly contagious, airborne, rod-shaped
organism (bacillus) that thrives on oxygen, grows slowly, and
possesses a "waxy" cell wall. The cell wall's structure and
function are not well understood but appear to allow the
bacteria to survive within immune cells called macrophages
(specialized cells that destroy bacteria and viruses). It also
provides the organism with a resistant barrier to many
common drugs. The bacteria's primary host is the human. Infection spreads
through direct person-to-person contact. When an infected
person talks, coughs, sings, or spits, tiny aerosolized droplets
containing bacteria are released into the air and inhaled by
uninfected persons. Viable bacteria can remain in the air for a
long In 1993, the WHO (World Health Organization) declared
tuberculosis a global emergency. Tuberculosis (TB) is
responsible for more deaths than any other infectious disease.
deaths Once called consumption, TB is a highly contagious,
persistent disease characterized by the formation of hard
grayish nodules, or tubercles. Because its signs and symptoms are easily confused with those
of many other (usually respiratory) diseases, tuberculosis can
be difficult to diagnose. Common symptoms are cough that is
worse in the morning and may include hemoptysis (i.e., blood
in the sputum), chest pain, night sweats, and breathlessness
(dyspnea). Incidence & Prevalence Of
Tuberculosis Mycobacterial disease is one of the world's most
difficult health problems. One-third of the population
worldwide is infected with TB. Of these, 8 to 10 million develop active disease and 3
million die each year. It is the greatest cause of death
in women of reproductive age; 900 million women
are currently infected. Of these, 2.5 million will
develop active disease and 1 million will die. TB lymph node involvement
Because of the chronic and persistent nature of the disease, effective treatment involves longterm multiple antibiotic treatment. Patients who are malnourished, under stress or afflicted with a compromised immune system are more prone to contracting TB, and with the outbreak of drugresistant strains, eliminating TB is a difficult and costly affair. The rate of tuberculosis infection in the United States had been
declining steadily until 1984 and then increased. Numerous factors account for the resurgence of tuberculosis in
the United States and in Europe.
They include the following: Emergence of multi drug-resistant strains of M. tuberculosis
M. Erosion of systems for diagnosis and treatment of the disease
Erosion Immigration of infected persons from countries where TB is
prevalent Prevalence of HIV (human immunodeficiency virus) infection
Reactivation of disease in the elderly
Reactivation Socioeconomic decline in urban areas Caused by M tuberculosis
Transmitted through airborne droplets
Lower respiratory inflammation lesions
confirmed by chest film
Fatigue, weight loss, fever
Treated with long term antibiotics IV. ACTINOMYCOSIS
IV. An infection of filamentous, branching, gram-positive
Actinomycetes are normal saprophytic components of
the oral flora. Documented sites of colonization in
healthy patients include the tonsillar crypts, dental
plaque and calculus, carious dentin, gingival sulci,
and periodontal pockets.
Actinomyces israelii is the most common culprit in
clinical CLINICAL FEATURES:
CLINICAL The most common sites of involvement in
actinomycosis are the cervicofacial, abdominal,
thoracic, cutaneous, and genital regions.
More than 50% of cases arise in the cervicofacial
The suppurative reaction of the infection may
discharge large yellowish flecks that represent
colonies of the bacteria called sulfur granules.
In the cervicofacial region, the organism typically
enters tissue through an area of prior trauma.
trauma Direct extension
through soft tissue is
seen, and lymph nodes
become involved only if
they are in the path of
the process. V. TETANUS
V. The bacterium Clostridium tetani produces a neurotoxin that interferes with the peripheral nerves of the spinal cord in the central nervous system. This neurotoxin inhibits the ability of these nerve cells to properly transmit signals to the muscle cells, causing the symptomatic spastic paralysis of tetanus because the muscle fibers are unable to relax in between contractions. “Lock Jaw”
•The bacteria is widely found in soil and transmission is usually through contaminated deep puncture wounds. If the wound environment becomes anaerobic, then the bacterium has an opportunity to multiply and allow its neurotoxin to spread systemically. It's not just a disease of rusty nails, but any soil contaminated injury. The microorganism has an incubation period of 321 days and can be prevented by immunization and booster injections. Caused by C tetani
Neurotoxin interferes with peripheral spinal
Found in soil and transmitted through deep
3-21 day incubation period
Prevented by immunization
Treated with antitoxin Patients with tetanus
After inoculation, tetanus can be treated by an antitoxin to block the action of the neurotoxin, but if left untreated, tetanus is frequently fatal. Prevention: Tetanus vaccine
Prevention: Infants should receive DTP vaccine as part of their routine
Adults should be given a routine booster dose of Td every 10
Adults without documentation of ever receiving the basic series
of tetanus and diphtheria toxoids should first receive a primary
series of three doses.
If someone experiences a deep or puncture wound, or a wound
contaminated with dirt, an additional booster dose may be given
if the last dose was more than five years ago.
It is important to keep an up-to-date record of all immunizations
so that repeat doses don't become necessary. Although it is vital
to be adequately protected against tetanus, receiving more doses
than recommended can lead to increased local reactions, such as
painful swelling of the arm.
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