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ANAEROBIC BACTERIA
Anaerobic Gram positive rods
Doç.Dr.Hrisi BAHAR
Istanbul University
Cerrahpasa Medical Faculty
1
ANAEROBIC GRAM
POSITIVE RODS
1*SPOROGENOUS ANAEROBIC
GRAM POSITIVE RODS
2* ASPOROGENOUS
ANAEROBIC GRAM POSITIVE
RODS
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SPOROGENOUS ANAEROBIC
GRAM POSITIVE RODS
CLOSTRIDIA
● Generally large rods that are often club
shaped due to presence of spore.
● Sporulation is variable
● All initially stain gram positive but may
become gram negative rapidly.
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Pathogenic Potential of
Clostridium-1-
● Very proteolytic and aerogenic;
elaborate multiple toxins.
● Common inhabitants of the
gastrointestinal tract and the female
genital tract.
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Pathogenic Potential of
Clostridium-2-
Some members associated with specific diseases.
● I.Gas Gangrene
C. perfringens (type A), C. septicum
C novyi type A, C. bifermentans
C. histolyticum, C. sordelli, C. sporogenes
● II.Tetanus - C. tetani
● III.Botulism - C. botulinum
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Pathogenic Potential of
Clostridium-3-
● IV.Antibiotic-associated Diarrhea
and Colitis
C. difficile; rare C. perfringens type C
● V.Miscellaneous infections - wounds,
abscess, soft tissue infection, myonecrosis,
bacteremia:
C. perfringens, C. ramosum, C. septicum, C.
sporogenes and others
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Tetanus
-1-
• The spores of C. tetani are found in
feces of humans and animals and in
soil.
* Signs and symptoms :Tetanus affects
skeletal muscles.
* Mortality rates vary from 40% to 78%.
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Tetanus
-2-
● Generalized tetanus is the most
common type of tetanus, representing
about 80% of cases.
● Neonatal tetanus is a form of
generalized tetanus that occurs in
newborns.
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Tetanus-3Neonatal tetanus
● A frequent cause of death in developing
countries
● Most common causes: cutting the umbilical
cord with unsterilized instruments or infection
of the umbilical stump
● The fatality rate: around 90%
● The common death cause: respiratory failure
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Tetanus
-4-
● Local tetanus
Uncommon form of the disease
● Cephalic tetanus is a rare form of the
disease
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Tetanus-5The tetanus toxin (tetanospasmin) travels
to the central nervous system and binds to
nerve tissue.
Prevents the inhibitory signals to the motor
neurons and results in prolonged
contraction of extensor and flexor
muscles.
C. tetani also produces tetanolysin.
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Tetanus-6-
● Muscle spasms mediated by
tetanospasmin produces a characteristic
arching posture known as opisthotonos.
● Without treatment, the patient ultimately
succumbs to respiratory failure.
● The incubation period ranges from 1-54
days; generally 6-15 days.
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Tetanus-7Opisthotonos
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Tetanus-8Diagnosis
● The diagnosis
is based on clinical symptoms and
patient history (i.e.lack of current vaccination).
● No attempt is made to cultivate the organism.
● A Gram stain of wound exudate (if available) may
demonstrate Gram positive rods and gram negative
rods with swollen ends due to the presence of
spores.
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Tetanus -9Latent period: 4-5d ～ several weeks
Lockjaw, sardonic smile
opisthotonos
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Tetanus-10-
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Tetanus -11Therapy
Treatment usually focuses on
● controlling muscle spasms,
● stopping toxin production and
● neutralizing the effects of the toxin.
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Botulism -1● The causative agent, C. botulinum, is found in
soil, freshwater, and seawater sediments.
● Botulism is a neuroparalytic disease .
● The toxin of C.botulinum acts by blocking nerve
function and leads to respiratory and
musculoskeletal paralysis.
● The toxin affects nerves,it affect specifically, the
inhibition of the release of acetylcholine from
motor neurons.
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Botulism -2● Botulism toxin is one of the most
powerful known toxins: about one
microgram is lethal to humans.
● In all cases illness is caused by the
toxin made by C. Botulinum.
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Botulism-3-
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Botulism -4Mode of acquisition
1-Infant botulism.
●The most common form in Western countries ,
●This occurs in small children who are colonised
with the bacterium during the early stages of their
life.
●The bacterium releases the toxin into the intestine,
the consumption of honey during the first year of life
has been identified as a risk factor for infant
botulism.
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Botulism -52-Foodborn botulism.
Results from contaminated foodstuffs in
which C. botulinum spores have been
allowed to germinate and produce botulism
toxin.
3-Wound botulism.
Results from the contamination of a wound
with the bacteria
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Botulism -6Diagnosis
● C.botulinum infections should be made
on clinical grounds.
● Confirmation of the diagnosis is made by
testing of a stool or enema specimen with
the mouse .
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Botulism -7-
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Botulism -8Treatment
* The only drug currently available to
treat infant botulism is “Botulism
Immunoglobulin Intravenous Human”.
* If diagnosed early, foodborne and
wound botulism can be treated by
inducing passive immunity with a
“horse-derived antitoxin”.
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Pseudomembranous colitis
-1-
● Infection of the colon,often,but not always
caused by the bacterium C.difficile.
● This disease is induced by long term use of
broad spectrum antibiotics
● It is characterized by the presence of colonic
plaques that form a pseudomembrane.
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Pseudomembranous colitis
-2-
● Key factor in the pathogenesis of PMC is a
disturbance of the normal bowel flora that
permits C. difficile to overgrow the
endogenous flora, produce toxin and induce
disease.
● Approximately 2% of healthy adults carry
C. difficile as commensal flora
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Pseudomembranous colitis
-3-
Diagnosis
● Visualization of characteristic
pseudomembranous plaques by
colonoscopy
● Detection of the toxin is the most accurate
diagnosis way but is difficult to perform.
● C. difficile can be cultured on special media
CCFA-cycloserine, cefoxitin, egg yolk,
fructose agar.
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Pseudomembranous colitis
MAP :Mitojen Activated Protein Kinases
-4-
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Pseudomembranous colitis
-5-
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Pseudomembranous colitis
-6-
● The disease is usually treated by oral
metronidasole (500 mg every 8 hours)
● Oral vancomycin (125 mg every 6 hours)
● Additionally treatment by probiotics
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Anaerobic cellulitis -1● Invasion of necrotic wound tissue by
the proteolytic clostridia.
● Characterized by gas accumulation,
discoloration of the underlying skin,
and the presence of a malodorous,
brownish, purulent discharge.
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Anaerobic cellulitis 2-
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Clostridial myonecrosis or
gas gangrene -1● Gas gangrene is associated with severe
deep wounds .
● Clostridial myonecrosis or Gas
gangrene develop in a lowered
oxidation-reduction potential present in
the wound.
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Clostridial myonecrosis or
gas gangrene -2This situation was caused by
● The presence of foreign bodies in the
wound,
● Failure of the blood supply to the infected
area,
● The presence of necrotic tissue and
hemorrhagie in the wound,
● The presence and multiplication of other
bacteria.
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Clostridial myonecrosis or
gas gangrene -3● Clinical features of gas gangrene include marked
systemic toxicity, fever,tachycardia, and a tender,
painful edematous wound with a sweet- or
foul-smelling discharge .
● The most frequently encountered species are C.
perfringens (predominant), C. novyi and C.
septicum, and Clostridium clostridiforme.
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Clostridial myonecrosis or
gas gangrene -4-
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C. perfringens food-borne
illness -1● This is reported to be the third most
common form of food poisoning in the
world.
● The predisposing factor appears to be the
ingestion of improperly cooked/stored
meat or meat product.
● Most patients are afebrile.
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C. perfringens food-borne
illness
-2-
● There is nausea and vomiting in one third
of the cases; stools are usually foamy and
foul smelling.
● The illness is usually mild and self-limiting.
● Diagnosis is confirmed by the recovery of
a large number of organisms (>108
spores/g feces) from stool.
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Isolation and Identification of
Clostridia
-1-
● Identification of the commonly
encountered clostridia can often be
accomplished on the basis of colony
morphology, growth on selective media,
aerotolerance determination and a few
screening tests.
● Egg Yolk agar (EYA) is commonly
employed for the identification of clostridia.
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Isolation and Identification of
Clostridia
-2-
● EYA is useful for the detection of two
enzymes: lecithinase - precipitation
around colony on EYA, lipase - iridescent
sheen at edge of colony on EYA.
● Alpha toxin is a specific form of
lecithinase produced by C. perfringens
and a few other clinically important
clostridia.
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NAGLER POSITIVE CLOSTRIDIA
• Clostridium perfringens
• Clostridium sordelii
• Clostridium bifermentans
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ASPOROGENOUS ANAEROBIC
GRAM POSITIVE RODS
● Heterogeneous group of organisms that
may be recovered as commensal flora on a
variety of mucosal surfaces including the:
upper respiratory tract, gastrointestinal
tract, female genitourinary tract.
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ASPOROGENOUS ANAEROBIC GRAM
POSITIVE RODS -1● The genera observed vary with the anatomic site.
These organisms are considered to be opportunistic
pathogens that take advantage of breaks in the
integrity of the mucosal surfaces.
● Usually recovered from polymicrobic infections
involving facultative bacteria (enterics,
staphylococci,streptococci) or anaerobic gram
negative rods (Bacteroides or Fusobacterium).
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ASPOROGENOUS ANAEROBIC GRAM
POSITIVE RODS -2-
The most commonly encountered genera are:
● Actinomyces,
● Bifidobacterium,
● Eubacterium,
● Propionibacterium,
● Mobiluncus,
● Lactobacillus
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ACTINOMYCES
• Actinomyces are
branching
anaerobic or
microaerophilic ,
non-sporulating
Gram positive
bacilli
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ACTINOMYCOSIS -1● Actinomycosis is an endogenous infection
caused by Actinomyces sp.
● The infection usually manifests as a chronic
suppurative disease that may produce
granulomatous lesions.
● The infection spreads by direct extension
through contiguous tissue including connective
tissue and bone .
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ACTINOMYCOSIS -3-
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ACTINOMYCOSIS -4Clinical manifestations include
● Cervicofacial
● Thoracic
● Abdominal
● Skin lesions
● Periodental diseases
● Pelvic infections.
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BIFIDOBACTERIUM
Pathogenicity
Members of this genus are oral and
intestinal commensal flora which are
associated with polymicrobic infections,
especially pulmonary.
They are rarely encountered in clinical
material.
B. dentium appears to be the only
species with pathogenic potential.
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BIFIDOBACTERIUM
Characteristics
● Gram stain demonstrates irregular
clusters of pleomorphic Gram positive rods
to filamentous or branching filamentous
forms.
● Bifidobacteria are strict anaerobes
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Bifidobacterium strains are
important probiotics
Different species and/or strains of Bifidobacteria may
exert a range of beneficial health effects, including
● The regulation of intestinal microbial
homeostasis
● The inhibition of pathogens and harmful
bacteria that colonize and/or infect the gut
mucosa
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Bifidobacterium strains are
important probiotics
● The modulation of local and systemic
immune responses
● The repression of procarcinogenic
enzymatic activities within the microbiota
● The production of vitamins, and the
bioconversion of a number of dietary
compounds into bioactive molecules
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PROBIOTICS
• According to the
currently adopted
definition by FAO/WHO,
probiotics are: "Live
microorganisms which
when administered in
adequate amounts
confer a health benefit
on the host.
• Lactic acid bacteria
(LAB) and
bifidobacteria are the
most common types of
microbes used as
probiotics
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BIFIDOBACTERIUM
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EUBACTERIUM.1.
Pathogenicity
● Members of the genus, primarily
E. lentum are rarely encountered in the
clinical setting.It is transfered to the genus
Eggerthella and called Eggerthella lenta
● Most isolates are recovered from
opportunistic,
polymicrobic infections.
● Recent studies indicate that some members of the
genus may be associated with periodontal infections
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PROPIONIBACTERIUM
• Pathogenicity:
*Commensal flora ofr the skin, found on mucosal
surfaces of the upper respiratory, gastrointestinal
and urogenital tract.
*Contaminant in specimens collected percutaneously.
• Propionibacteria have been recovered from
infections involving prosthetic heart valves and joints
as well as ventricular shunts.
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PROPIONIBACTERIUM
● Sequelae have included osteomyelitis,
septicemia, endocarditis and meningitis.
● P. acnes plays a role in the development
of acne.
● P.propionicus, which closely resembles
A.israelii, has been isolated also from
cases of actinomycosis.
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PROPIONIBACTERIUM
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LACTOBACILLUS
● Pathogenicity:
Lactobacilli are the
predominant commensal flora of the UGT in
postpubescent females; they are also
commensal flora of the oral cavity and intestinal
tract.
● Members are rarely associated with infections.
However, lactobacilli have been recovered from
cases of endocarditis, neonatal meningitis,
chorioamnionitis as well as bacteremia and
pulmonary infections.
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LACTOBACILLUS
Characteristics:
● Most members are aerotolerant, producing
larger colonies when grown anaerobically.
● Lactobacillus strains are important probiotics
● Lactobacilli ferment carbohydrates mainly to
lactic acid.
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MOBILUNCUS
Pathogenicity
● Members of the genus are commensal flora for the
genital tract and terminal portion of the gastrointestinal
tract (rectum).
● These organisms have been isolated from 50-65% of
women diagnosed with bacterial vaginosis as well as
the sex partners of these women.
● The organisms have the ability to attach to vaginal
epithelial cells in conjunction with Gardnerella vaginalis
to form "clue cells". Mobiluncus species have been
recovered from women with Pelvic Inflammatory
Diseases.
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MOBILUNCUS
Characteristics:
● Members of the genus are the only
asporogenous anaerobic gram positive
rod, clinically encountered, that are usually
motile.
● Cells are gram positive to gram variable
and may be curved.
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MOBILUNCUS
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