Download Bacillus anthracis

Aerobic and anaerobic sporeforming Gram-positive rods:
Bacillus and Clostridium genus
Obligate anaerobic bacteria
Katalin Kristóf MD.
Gram-positive, Aerobic or Facultative
Endospore-forming Bacteria (formerly,
"The Genus Bacillus")
Todar's Online Textbook of Bacteriology
In 1872, Ferdinand Cohn, a contemporary of Robert Koch,
recognized and named the bacterium Bacillus subtilis.
The organism is Gram-positive,
capable of growth in the presence of oxygen,
and forms a unique type of resting cell called an endospore.
Endospores
The formation of endospores is a complex and highly-regulated form, the process of
spore formation can be divided into seven defined stages (0-VI).
The vegetative cell begins spore development when the DNA coils along the central
axis of the cell as an "axial filament„,
b)
The DNA then separates and one chromosome becomes enclosed in plasma
membrane to form a protoplast,
c)
The protoplast is then engulfed by the mother cell membrane to form a intermediate
structure called a forespore,
d)
Between the two membranes, The core (cell) wall, cortex and spore coats are
synthesized,
e)
As water is removed from the spore and as it matures, it becomes increasingly heat
resistant and more refractile,
f)
The mature spore is eventually liberated by lysis of the mother cell.
The entire process takes place over a period of 6-7 hours and requires the temporal
regulation of more than 50 unique genes (Pasteur Institute).
a)
In cross section, Bacillus spores show a more complex
ultrastructure (by Viake Haas, University of Wisconsin)
The spore protoplast (core; calciumdipicolate) is surrounded by:
The core wall is composed of the
same type of peptidoglycan as the
vegetative cell wall;
The cortex is composed of a unique
peptidoglycan;
The outer spore coat
represents 30-60 percent of the dry
weight of the spore.
The spore coat proteins have an
unusually high content of cysteine and of
hydrophobic amino acids, and are highly
resistant to treatments that solubilize
most proteins.
Depending on the species, an exosporium
may be present
Endospore – cryptobiotic state
They are highly resistant to environmental stresses
- high temperature (some endospores can be boiled for
several hours and retain their viability),
- irradiation,
- strong acids,
- disinfectants, etc.
Their differentiation begins when a population of vegetative
cells passes out of the exponential phase of growth, usually
as a result of nutrient depletion.
They germinate and become vegetative cells when the
environmental stress is relieved.
Endospore-formation is a mechanism of survival (millions of
years) rather than a mechanism of reproduction.
Classification and Phylogeny
Their taxonomic hierarchy (Bergey's 2004)
/largely by analysis of 16S rRNA molecules by oligonucleotide
sequencing /
Kingdom: Bacteria;
Phylum: Firmicutes;
Class: Bacilli;
Order: Bacillales;
- Family: Acyclobacillaceae (genus: Acyclobacillus);
- Family: Bacillaceae (genus: Bacillus, Geobacillus);
- Family: Paenibacillaceae (genus: Paenibacillus,
Brevibacillus);
- Family: Planococcaceae (genus: Sporosarcina).
Robert Koch's original photomicrographs of
Bacillus anthracis, the agent of anthrax (1877)
The anthrax bacillus, Bacillus anthracis, was the first bacterium shown
to be the cause of a disease. In 1877, Robert Koch grew the organism in
pure culture, demonstrated its ability to form endospores, and produced
experimental anthrax by injecting it into animals.
Bacillus anthracis
Morphology:
- large (3-8um) Grampositive rods with
characteristic squared ends
- ovale spore in the center
- spores do not deform the
shape of the bacteria
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Bacillus anthracis
Morphology:
- capsule from
D- glutamic
acid
- no motile
Left:India ink capsule outline 1000X.
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Right a fluorescent-labeled antibody is reacted specifically with the capsular material which renders
the capsule fluorescent 1000X.
Bacillus anthracis
Cultivation:
⇒„simpleagar”:
dry, groundglass
appearance
⇒ Blood agar:
no
haemolysis
Virulence factors (encoded by plasmids)
pX02 ⇒ Poly-D-glutamyl capsule
protect the organism against complement and the
bactericidal components of serum and phagocytes, and
against phagocyte engulfment and destruction.
plays most important role during the establishment of the
infection, and a less significant role in the terminal
phases of the disease.
Mucoid colonies of Bacillus anthracis.
This culture was probably incubated
at an increased CO2 tension (5%
CO2) which greatly enhances
production of the poly-D-glutamyl
capsule and accounts for the mucoid
colony type.
pX01 ⇒
Factor I =Edema
factor (EF) :
calmodulindependent adenylate
cyclase
Factor II
=Protective antigen
(PA), binds to
specific receptors on
the host cell surface
– as the B „binding”
moiety)
Factor III = Lethal
factor (LF) : Znmetalloprotease,
leading to cell death
PA binds to
receptors on host
cell surfaces:
Brain, heart,
intestine, lung,
skeletal
muscle,
pancreas,
macrophages
Virulent
anthrax bacilli
multiply at the
site of the
lesion
- capsule!
A short range effect
of the toxin is its
further impairment of
phagocytic activity
and its lethal effect
on leukocytes,
including
phagocytes, at the
site.
After the organisms
and their toxin enter
the circulation, the
systemic pathology,
which may be lethal,
will result
Combinations of two or three of the toxin
components yield the following results
PA+LF combine to produce lethal activity
EF+PA produce edema
PA+LF+EF produces edema and necrosis and is
lethal
Epidemiology:
Anthrax is primarily a disease of domesticated and wild
animals, particularly herbivorous animals – „black-bone”
(cattle, sheep, horses, mules and goats)
Humans become infected incidentally when brought into
contact with diseased animals, which includes their flesh,
bones, hides, hair and excrement.
Even in endemic areas, anthrax occurs irregularly, often
with many years between occurrences.
In the United States: 1-2 cases of cutaneous disease per
year
2001: 22 cases of anthrax (11 inhalation, 11 cutaneous)
were identified in the USA following intentional
contamination of the mail (5 death).
Bioterrorism!
Anthrax cases - natural
1.
2. 1. Epidemy (animals)
2. Local infection (animals)
Forrás: anthrax BBC tények
Human Diseases
1. Cutaneous anthrax :
malignant pustule (95%)
→ spores from the soil or a
contaminated animal through
injured skin
→ the spores germinate
→ vegetative cells multiply
→ characteristic edema and
→ painless papule at the site
of inoculation
→ progressing to an ulcer
surrounded by vesicles
→ necrosis
Day 6
Malignant pustule
Day 10
Day 15
Local laesion + oedema
Source: CDC Anthrax Images
Pustula maligna + oedema
Pustula maligna and oedema
2. Pulmonary anthrax („wool
sorters’ disease”):
Inhalation → hemorrhagic
pneumonia, mediastinitis →
respiratory failure
The disease begins abruptly
with high fever and chest pain.
It progresses rapidly to a
systemic hemorrhagic
pathology and is often fatal if
treatment cannot stop the
invasive aspect of the
infection.
Biological weapon !
Inhalation/Lung anthrax (X-ray)
Mediastinal widening
Source: CDC Anthrax Images
… and pleural effusion
3. Gastrointestinal anthrax - Bloody diarrhoea:
Ingestion of spores (very rare in humans!)
Ulcers form at site of invasion (mouth, oesophagus, intestine)
→ mesenteric lymphadenopathy → abdominal pain,
vomiting → oedema, sepsis (100% mortality)
Bacillus anthracis - Biological Warfare
Anthrax spores may survive in the soil, water and/or
surfaces for many years
a cloud of anthrax spores would be released at a strategic
location to be inhaled by the individuals under attack
hemorrhagic pneumonia
an infection of local animal populations (sheep, cattle) could
follow a biological attack with spores
infected animals could then transmit the disease to humans
Diagnosis:
1.
2.
Smear: fluid from local
lesion
Cultivation
1.
2.
3.
Non-hemolytic, adherent
colonies
McFadyean's reaction showing short chains
Morphology
Bacillus anthracis cells lying among
Confirmed by demonstrating of
amorphous, disintegrated capsular material.
capsule (india-ink, DFA) or White blood cells can also be seen
by lysis with gamma phage
3. PCR (pX01, pX02)
4. LF protein detection
5. Anti-PA IgG ELISA
Therapy:
Quinolones (penicillin, tetracyclin)
administered before the onset of lymphatic spread!
Anthrax immune globulin
Prevention:
Possible vaccination for „risk” groups
protective antigen recovered from the culture filtrate of an
avirulent, nonencapsulated strain of Bacillus anthracis that
produces PA during active growth (6 subcutaneous injections,
annual booster injections)
Vaccination of animals (Pasteur 1881)
Burning of burial of animals that died of anthrax
Bacillus cereus
Morphology: Gram-positive, spore-forming rod
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Bacillus cereus
Cultivation :
„simple” agar:
„cut-glass” appearence
Blood agar:
β - hemolysis
Egg-yolk agar:
lecitinase
reaction
Clinical findings
1. Food poisoning - food-borne illnesses
A) Emetic form („short incubation”, like S.aureus~)
from contaminated rice dishes that have been cooked and then
held at warm temperatures for several hours; Mexican and Chinese
restaurants
1-6 hrs incubation period
nausea, vomiting, abdominal cramps
Heat-stable enterotoxin: emetic toxin (?)
B) Diarrheal form („long incubation form”, like
C.perfringens~)
From contaminated meat, vegetables, sauces
8-16 hrs incubation period
abdominal cramps, watery diarrhoeae
Heat-labile enterotoxin:acts by activation of adenylate
cyclase enzymes.
Diagnosis
-
-
The emetic form of the disease is diagnosed by the isolation of B.
cereus from the incriminated food (greater than or equal to 105 B.
cereus organisms per gram)
The long-incubation form is diagnosed by isolation of the organism
from stool and food.
Treatment
-
Because B. cereus gastroenteritis is generally
a benign, self-limited illness, antimicrobial
agents are of no value in management.
Prevention
-
Since the bacteria grow best at temperatures ranging from 4 to 60 °C,
infection may be prevented if cold food is refrigerated and if hot food
is held at greater than 60°C before serving.
2. Ocular infection
After traumatic, penetrating injuries
IV. drug users – systemic diseaes
Virulence factors:
Necrotic toxin,
cereolysin (hemolysin),
phospholipase C (lecithinase)
Treatment: vancomycin, clindamycin, fluoroquinolones
3. Intravascular catheter-associated infection, sepsis
4. Fatal pneumonia?
Other aerobic sporeformers
Antibiotic Producers: antibiotics
produced by the are often, but not
always, polypeptides.
Brevibacillus brevis (e.g. gramicidin,
tyrothricin),
Bacillus cereus (e.g. cerexin,
zwittermicin),
Bacillus circulans (e.g. circulin),
Brevibacillus laterosporus (e.g.
laterosporin),
Bacillus licheniformis (e.g. bacitracin),
Paenibacillus polymyxa (e.g. polymyxin,
colistin),
Bacillus pumilus (e.g. pumulin)
Bacillus subtilis (e.g. polymyxin,
difficidin, subtilin, mycobacillin).
Paenibacillus alvei, B. megaterium, B. coagulans, Brevibacillus
laterosporus, B. subtilis, B. sphaericus, B. circulans,
Brevibacillus brevis, B. licheniformis, P. macerans, B. pumilus
and B. thuringiensis have been occasionally isolated from human
infections.
Gastroenteritis, opportunistic infection
Geobacillus stearothermophilus
are used to test heat sterilization procedures
THE CONTROL OF THE AUTOCLAVE’S NORMAL
FUNCTION
-NORMAL FUNCTION- the spores consume, the color is yellow
-NOT NORMAL FUNCTION - the spores survive, and start to
germinate, multiply, the color will be change from purple to yellow
Anaerobes: general characteristics
1. For growing: → low oxido-reduction potencial
Don’t able to grow on the rigid cultivation surface,
if >10% CO2; >18% O2 (def. by Finegold)
2. Anaerobic bacteria do not have
Cytochrome system for oxygen metabolism
Superoxide-dismutase
2O2 + 2H+→O2 + H2 O2
Catalase (partly)
H2O2 + H2O2 → 2H2O + O2
Peroxidase (partly)
H2O2 + H2R → 2H2O + R
Effects of oxygen on aerobic, anaerobic, and
facultative anaerobic bacteria
3. Anaerobes are part of the normal flora
Mouth
CFU/ml
109/ml
aerob/anaerob
1/30
Colon
1011/ml
1/1000
(100-400 different
anaerobic species)
Vagina
107/ml
skin
?
?
10/1
genus
Peptococcus,Peptostreptococcus,
Lactobacillus, Bifidobacterium,
Actinomyces, Bacteroides,
Porphyromonas, Fusobacterium,
Treponema, …
Peptococcus,Peptostreptococcus,
Lactobacillus, Bifidobacterium,
Eubacterium, Clostridium,
Bacteroides, Porphyromonas,
Fusobacterium
Lactobacillus, Bifidobacterium,
Peptostreptococcus,
Eubacterium,
Bacteroides, Prevotella, …
P.acnes, other
Propionibacterium
4. Anaerobes are potentially pathogenic when displaced from
normal environments and implanted in dead or dying tissue
- predisposing factors!
medmicro
Types of infection commonly produced by anaerobic bacteria
disease
bacteriemia
Brain abscesses
subdurale empyema
chronic otitis media
After aspirations → pneumonia
Lung abscessus
Intra-abdominal infections
Liver abscessus
appendicitis, peritonitis
Vulvovaginale abscessus
Pelvic inflammation
endometritis
Bacterial vaginosis
5. Often cause polymicrobial infection
frequency
5-20 %
89%
10%
52%
93%
95%
93%
50-100%
96%
74%
92%
73%
100%
Disease caused by anaerobic bacteria
Exogen infection
Spore-forming clostridia
Monobacterial
Toxin-mediated
Endogen infection
Non spore-forming bacteria
Polymicrobial infection
Complex pathogenesis
Predisposing factors:
O2 ↓: shock, angiopathia, d.m.,
„cut the barrier”: aspiartion, operation, trauma,
Clostridia-general characteristics
Clostridia are strictly anaerobic to aerotolerant
sporeforming bacilli
Found in soil as well as in normal intestinal flora of man
and animals
Large, Gram-positive rods
Form characteristic spores, the position of which is useful in
species identification
Wide variety of extracellular enzymes (biodegradation &
invasive infection)
Exotoxin production
Classification and Phylogeny
Their taxonomic hierarchy (Bergey's 2004)
/largely by analysis of 16S rRNA molecules by
oligonucleotide sequencing /
Kingdom: Bacteria;
Phylum: Firmicutes;
Class: Clostridia;
Order: Clostridiales;
- Family: Clostridiaceae
11 genera, including Clostridium genus
Clostridium perfringens
Large, (1-2 um * 7-8 um), ovale-spores are central
Non-motile, has capsule
oregonstate.edu/research/Images/SarkerSlide.jpg
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Clostridium perfringens
Blood agar plate: double β, α-hemolysis
Metabolically active → gas production (CO2, H2S,CH4)
Clostridium perfringens
Type : A, B, C, D, and E
Toxins:
α-toxin = lecithinase, phospholipase C
Damage to cell membrane
Lysis of RBC, WBC, PLT, endothelial cells
Increased vascular permeability with massive haemolysis & bleeding, tissue
destruction
Hepatic toxicity + myocardial dysfunction
β-toxin → necrotizing activity
ε-toxin → increases vascular permeability of the GI wall
Iota-toxin → the same + necrotic activity
Enterotoxin (superantigen)
Enzymes:
Collagenases, hyaluronidases, DN-ase, lipases, proteases
1. Gas gangrene:
- Exogenic infection
-penetrating wound,
contaminated with
spores
- Endogenic infection:
after gut ruptura,
appendicitis perforata
(rare),
after amputation
- Septic abortus
Gas gangrene is the most deadly type of gangrenous infection because it spreads so rapidly
and does the most damage.
Incubation period:1-3days
→ Pain, edema around the
infected wound
→ Severe systemic, toxic
symptoms, high fever
→ Brownish, or bloody
serous exudate with the
discoloration of the
surrounding skin
→ foul or sweet smell
→ Gas is detected among
tissues (blood vessel
compression - ischemia)
Diagnosis
Clinical specimen: pus, necrotic tissue, blood
Direct smear, cultivation
Spores and WBC-s are not
seen in smears from clinical
samples
Phase-contrast M
Nagler plate
lecithinase activity - when a culture is grown on a
medium rich in phospholipids such as egg yolk agar,
lecithinase activity is detected as a opalescence
which develops around the colonies as the
phospholipids are split into insoluble diglycerides.
Nagler-reaction positive
- neutralisation of lecithinase C
by a specific antitoxin
Treatment
It can be fatal if not treated immediately
Surgical debridements (amputation)
Very high dose penicillin therapy
The role of hyperbaric oxygen remains controversial
Supportive therapy
G-CSF
Prevention
State of art surgical management of wound in regard
preventing from anaerobic conditions is essential.
Gas gangrene - other clostridia
C. septicum 20 %
motile, peritrich flagellae
α-toxin => necrotic, haemolytic activity
/From blood culture – underlying intestinal malignancy!/
C. novyi A
40%
Motile, peritrich flagellae
Toxaemia
α, β, δ, ε toxin => haemolytic, necrotic activity
phospholipases, lipases
C. histolyticum 10-20%
C. sordelii
Clostridium septicum
Necrotizing fasciitis
Background: colon tumor
Hello
My name is C. perfringens.
I'm a Gram Positive rod and anaerobic.
I live in soil and can make spores to survive to for a long
time.
I can cause myonecrosis, or "gas gangrene".
I get into your muscles in wounds and make toxins.
As I eat away at your muscles, I let off gases that build up
between them.
When I am "type A", I can cause food poisoning.
I live in undercooked meat and make spores in your gut.
I make an enterotoxin that gives you cramping and
diarrhoea.
My "type C" form causes "necrotising enteritis".
You have to eat undercooked pork with me in it.
You also have to eat a lot of foods like sweet potatoes,
which have a chemical called trypsin inhibitor in them.
When they are together, I can make my β-toxin and eat
away at your bowels.
Clostridium perfringens–2. Food poisoning
Clostridium perfringens „A” produces an enterotoxin and is an
important cause of food poisoning
C. perfringens is a ubiquitous, and a frequent contaminant of
meat and poultry.
By sporulating, this organism can survive high temperatures
during initial cooking; the spores germinate during cooling
of the food, and vegetative forms of the organism multiply if
the food is subsequently held at temperatures of 16-52oC.
If served without adequate reheating, live vegetative forms of
C. perfringens may be ingested. The bacteria then elaborate
the enterotoxin
8-24 hours incubation period
Watery diarrhea, abdominal cramping, vomiting, fever
Self-limited (24-48 hours)
Clostridium perfringens–2. Food poisoning
Diagnosis:
Enterotoxin detection – from fecal sample
Cultivation: greater than or equal to 105 organisms per gram of
epidemiologically implicated food.
An alternate criterion is that cultures of stool samples from persons
affected yield greater than or equal to 106 colonies per gram
C. perfringens–3.enteritis necrotisans
β-toxin producing „C” type
Incubation period:8-12 h
(pork meat)
Necrotic lesions in jejunum,
Bloody diarrhea,
peritonitis,
shock
High mortality
Diagnosis:
Enterotoxin detection – from
fecal sample
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Clostridium tetani
Morphology: ⇒ Gram-positive rods, spores are terminal
(cells look like drumsticks)
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Clostridium tetani
Cultivation: more sensitive to oxygen
Broth culture:no evidence of gas
production
Dextrose-blood agar: greyish colonies,
no hemolysis
Clostridium tetani
Found in soil & colonizes
the GI tract of many
animals & humans (0-25%)
small puncture wounds or
lacerations which become
contaminated with C. tetani
spores that germinate and
produce toxin
Incubation period varies 45 days to weeks
tetanus is a highly fatal
disease of humans
mortality rates reported
vary from 40% to 78%
Clostridium tetani
Tetanospazmin (subunit A and B)
Heat-labile, plasmid encoded
Produced during stationary phase of growth
Released when the cell is lysed
Being internalized & moves from the peripheral nerve terminals to
the central nervous system by retrograde axonal transport
Being released from the postsynaptic dendrites
Localized within vesicles in the presynaptic nerve terminals
Acts by blocking the release of inhibitory neurotransmitters
(GABA)
Causing exitatory synaptic activity to be unregulated
Tetanus
Generalized: the most frequent type
Trismus /lockjaw:spasms of the masseter
muscles
Sardonic smile/risus sardonicus:facial
muscles
Opisthotonus :persistent back spasms
irritability
Involvement of the autonomic nervous system
(cardiac arrhytmias,...
Neonatal
The site of primary infection is the
umbilical stump
Progresses to generalized – 90% mortality
rate
Localized
Cephalic
Clostridium tetani
Sir Charles Bell’s portrait of a soldier dying of tetanus
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Laboratory diagnosis:
Clinical symptoms (anamnesis, immunization history)
Culture from wounds are not useful…
Samples for antitoxin level (DD:strychnine poisoning)
Treatment:
passive immunisation with antitoxin (Human Tetanus
Immunoglobulin)
Surgical management
Tetanus toxoid – active immunisation
Metronidazol
Critical care unit
Prevention:
/even a lethal dose of tetanospasmin is insufficient to provoke an immune
response/
Prophylactic immunization is accomplished with tetanus toxoid,
as part of the DPT (DTaP) vaccine or the DT (TD) vaccine..
Clostridium botulinum
Morphology: Gram positive rods, subterminal spore
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Clostridium botulinum
Botulinum toxin:
Group I: A, B, F
Group II: B, E, F
Group III: C, D,
Group IV: G
„B” : protects the toxic subunit
from being inactivated by
gastric acids
A : Specific for cholinerg
nerves (neurotoxin)
Blocks the release of
acetylcholine at
peripheral cholinerg synapses
Flaccid paralysis
• Single strain almost always
produces only one toxin type
• 1 mg 30M LD50 mouse D
• Spores are found throughout
the world in soil samples and
marine sediments
• These spores are able to
tolerate 100°C for hours
Clostridium botulinum
Clinical syndromes
1. Foodborne botulism – Intoxication
Fish fillets
Canned salmon
Corned beef
Pasta products
Canned
vegetables
toxin production outside the body
After 1-2 days of consuming the contaminated food
Blurred vision, fixed dilated pupils
Dry mouth, constipation, abdominal pain
Bilateral descending weakness of the peripheral muscles
flaccid paralysis (symmetrical)
Death – due to respiratory paralysis
Clear sensorium through out the disease, no fever
Blurred vision, fixed dilated pupils
dry, furrowed tongue
2. Infant botulism – infection caused by
toxin producing in vivo
Bacteria can colonise the GI tract of infants
younger than 6 months – the absence of
competitive bowel microbes
Source of infection : honey
constipation, weak sucking ability and
generalized weakness
Possible cause of sudden infant death
3. Wound botulism
Symptoms are similar
to those of foodborne infection
Incubation period is longer
Clostridium botulinum
Diagnosis:
Isolation of microorganism – faeces, food
Toxin activity – serum, faeces, food
ELISA
Animal inoculation (mouse bioassay)
Treatment:
Passive immunisation as soon as possible with trivalent
(A,B,E) antitoxic serum (equine)
Supportive therapy
Prevention:
Proper food handling and preparation
Clostridium difficile
Part of the normal GI flora
in a small number
Pathogenesis:
Endogenous source disease:
Broad spectrum
antibiotics alters the
normal enteric flora
Permitting the
overgrowth of C.difficile
antibiotic associated
diarrhea
pseudomembranous
colitis
Clostridium difficile
Exogenous source:
The hospitalized patient more susceptible to the exogenous
aquisition of C.difficile – nosocomial infection
Proliferation in the colon
A toxin : mainly enterotoxin
B toxin : cytotoxin
toxin production
hemorrhagic necrosis
Treatment: atb EX,
+ metronidazole or vancomycin administered orally
Fecal transplantation
Clostridium difficile
CDAD: an emerging public health crisis
Hypervirulent toxin-producing strains – O27/NAP1
Many severe cases
+ binary toxin (ADP ribosylating toxin)
Clostridium difficile
Diagnosis:
Rapid test: toxin detection
Immunochromatogen
PCR
ELISA, EIA
Cultivation
CCFA (the colonies are
generally flat, gray in colour,
with irregular margin and
ground-glass appearence;
Distinctive „barnyard” odour
Antibiotic-associated colitis. Assay of C. difficile toxin showing normal babyhamster kidney cells (left) and cells after exposure to toxin (right). Note rounding
up of cells folowing exposure to toxin.
Gram negative anaerobic bacteria
Bacteroides fragilis
Prevotella spp.
P.bivia, P.disiens
Porphyromonas spp.
F. nucleatum,
- GI
- intraabdominal infection
- mouth
- periodontitis, orofacial abscess
- vagina
- pelvic abscessus
- mouth
- periodontitis, orofacial abscess
- mouth, colon, vagina
- mixed pyogenic infection
F.perodonticum
„
- lower respiratory tract infection
F. mortiferum
„
- intraabdominal infection
F. necrophorum
„
- pelvic abscessus
Leptotrichia buccalis - mouth
- ulcerative gingivo-stomatitis
Gram negative anaerobic bacteria
Bacteroides (B.fragilis, B.distanosis,…)
capsular polysaccharide
superoxid dismutase
hyaluronidase, fibrinolysin, DN-ase, heparinase
Prevotella (P. melaninogenica, P. bivia…)
IgA protease
collagenase, fibrinolysin
Porphyromonas (P.asaccharolytica, P.gingivalis)
has trypsin-like activity
collagenase
Fusobacterium (F. nucleatum, F. varium)
Gram negative anaerobic bacteria
medmicro
Vincent’s angina
Ulcerative tonsillitis
causing tissue
necrosis often due to
extension of acute
ulcerative gingivitis
Fusobacterium
nucleatum in
combination with oral
spirochates
(Treponema vincentii
and others) causes the
fusospirochaetal
infections
www.lg1.ch
Giemsa stained smear - Angina Plaut-Vincent
Acute necrotizing ulcerative gingivitis (Vincent’s infection. Ulceration of the
gingival margin spreading into the gums.
NOMA
Bacterial necrosis that develops in the
mouth and ravages the faces of its
victims.
It destroys both the soft and bone
tissues of the face and mostly affects
young children between the ages of two
and six.
As the disease progresses, the jaws
become locked. Victims slowly lose the
use of their mouths.
The infection gradually attacks the nose
and sometimes the eyes, making it
difficult to eat, breathe or see.
80 percent death rate
peritonitis
Lung abscess
Most (>90%) cases of lung abscess
reflect the aspiration of anaerobic
bacteria from the oropharynx.
The infections are typically
polymicrobial, with fusiform
bacteria and Bacteroides species
often isolated.
Other organisms encountered in
lung abscesses caused by aspiration
include S. aureus, K. pneumoniae,
S. pneumoniae, and Nocardia.
Bacterial vaginosis.
The clue-cell – a vaginal
epithelial cell with
attached microorganism.
The attached bacteria
give the clue cell a
stippled appearance.
periodontitis
Gram negative anaerobic bacteria
Fusobacterium
nucleatum
(Vincent’disease)
Fusobacterium sp.
Fusobacterium spp.
pharmacie.univ-lille2.fr
Bacteroides fragilis
capsular polysaccharide
superoxid dismutase
hyaluronidase, fibrinolysin, DN-ase, heparinase
Bacteroides Bile Esculin Agar (BBE)
Colonies of Bacteroides
fragilis growing on an
agar surface
www.bdj.co.jp
web.bio.ed.ac.uk
Eosin/Carbol fuchsin
capsule smear of
population of B. fragilis
grown in defined
medium broth showing
phase variation; note
non-capsulate bacteria
and those with small
and large capsules
(viewed with x100
objective).
www.sanger.ac.uk
Prevotella melaninogenica
Prevotella
(P.melaninogenica, P.
bivia…)
- IgA protease
- collagenase,
- fibrinolysin
Prevotella intermedia
Porphyromonas spp.
Anaerobic cocci
Changing of the nomenclature
Changing of the clinical relevance
Diagnostic problems
Anaerobic cocci
Gram-negative :
Veilonella spp., Acidaminococcus fermentans, Megasphera
elsdenii
normal flora: mouth, skin, intestinal tract, genitourinary tract
infection is usually results from invasion of damaged tissue by normal
microbial flora
Gram-positive
Peptostreptococcus anaerobius, Peptococcus niger, Finegoldia
magna, Anaerococcus spp., Gallicola sp, Micromonas sp.,
Peptoniphilus spp., Atopobium parvulum
normal flora: mouth, skin, intestinal tract, genitourinary tract
clinical manifestation: a great variety of infections : abscesses, gangrene,
cellulitis, bacteraemia, pneumonia, peritonitis, bite wounds, pelvic
inflammatory disease
Mixed infection
Fig. 2.92 Lung abscess. Gram stain of pus showing Gram-positive cocci and
varoius Gram negative and Gram positive rods. By courtesy of J.R. Cantey
Isolation and identification of anaerobes
MIC
PCR
General laboratory diagnosis
Anaerobic conditions are required for sample collection,
culturing and identification
Antibiotics : after MIC determination
metronidazol
clindamycin
imipenem
penicillin
Chloramphenicol
resistance
intrinsic/natural : aminoglycosides!
Extrinsic/acquired:
beta-lactamase; B.fragilis penicillin R
PBP changing; cefoxitin R bacteroides
OMP permeabilitate changing; pl.cefoxitin R bacteroides
tetracyclin R
metronidazol R
chloramphenicol R
Thank you for your attention!