gram negative uph
TRANSCRIPT
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HAEMOPHILLUS
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Haemophilus Influenzae:
Clinical Infections
Infections caused by typable (encapsulated) strains
Acute epiglottis or laryngotracheal infection in small
children
Cellulitis/arthritisMeningitis
Pneumonia/septicemia (in children)
Conjunctivitis
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Haemophilus Influenzae:
Clinical Infections
Infections caused by Nontypable strains
Otitis media
Sinusitis
Pneumonia, bronchitis (in adults)
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Haemophilus Species
Haemophilus species require hemoglobin for growth:
X-factor ( hemin): Heat-stable substanceV-factor (NAD): Heat- labile, coenzyme I, nicotinamide
adenine dinucleotide, found in blood or secreted by
certain organisms
H. influenzae
satellitism around
and between the
large, white,hemolytic
staphylococci
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Haemophilus Species
Direct smear of H. influenzaein CSF in acase of meningitis. Note the intracellular
and extracellular pleomorphic gram-
negative bacilli.
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Haemophilus species
H.influenzaegrowing on
chocolate agar. Notice the
semi-opaque, gray-white,
mucoid colonies characteristic
of encapsulated strains.
Gram stain of H. influenzae
from colony
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Haemophilus Species:
Identification
This organism would be identified as H. influenzae
because it is using both X and V factors.
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Haemophilus Species:
Identification
This organism would be identified as H.parainfluenzaebecause it is using V factor only.
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Haemophilus Species:
Identification
This organism would be identified as H. aphrophilus because it is
using X factor only.
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Haemophilus Species:
Identification
Under ultraviolet light, the organism on the bottomis showing a positive porphyrin reaction, whereas
the organism on the top is demonstrating a
negative porphyrin reaction.
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BORDETELLA
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Bordetella
Classificationthe genus contains three medially
important species
B. pertussisB. parapertussis
B. bronchoseptica
Morphology and cultural characteristics
Small g-cb
B. parapertussisandB. bronchosepticaboth grow on
sheep BA (SBA) in 1-2 days
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BordetellaB. pertussisfor initial isolation (The best clinical
specimen is a nasopharyngeal swab.) theorganism requires special media with additional
nutrients for growth and absorbents to removetoxic substancesfound in complex media such as
fatty acids and sulfides.Borget-Gengou mediacontains glycerol, potato
infusion, albumin (binds fatty acids), and up to 50%defibrinated SRBCs
Charcoal agarsupplemented with 10% horse bloodwith or without cephalexin.
May take 3-7 days for growth and colonies aresmooth, raised, and glistening (phase 1 colonies).
They are also hemolytic and produce toxin.
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Charcoal-horse blood agar
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Bordetella
Virulence factors (B. pertussis)
Pili for attachmentPertactin, an outer membrane protein also acts
as an adhesion
Filamentous hemagglutininis found on the
cell surface of and is also secreted.It attaches to cilia by binding to exposed lactose
receptors.
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Bordetella
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BordetellaPertussis toxin
Secreted by type IV secretion system
Has one A subunit (toxic part), plus four different kinds of B
subunits (involved in binding).
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Bordetella
Clinical significanceB. pertussiscauses whooping cough
Acquired by inhalation of droplets containing theorganism
The organism attaches to the ciliated cells of therespiratory tract.
During an incubation period of 1-2 weeks, the organismmultiplies and starts to liberate its toxins.
Next the catarrhal stage occurs - the patient has a
mild cough and sneezing whereby large numbers oforganisms are spread through the respiratory
secretions.
This last ~ 2 weeks.
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Bordetella
Next is the paroxysmal stage that lasts 4-6 weeks.The patient has rapid, consecutive coughs with a rapid intake
of air between the coughs (has a whooping sound).
The ciliary action of the respiratory tract has beencompromised, mucous has accumulated, and the patient is
trying to cough up the mucous accumulations.
The coughs are strong enough to break ribs!
Other symptoms due to the activity of the released toxinsinclude:
Increased peripheral lymphocytes due to a blocking ofhoming of lymphocytes to the spleen and lymph nodes.
Metabolic alteration such as increased insulin release andthe resulting hypoglycemia
Increased capillary permeability and increasedsusceptibility to histamine, serotonin, and endotoxin
shock
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Bordetella
Finally there is a convalescent stage during which
symptoms gradually subside.
This can last for months.
B. pertussis rarely spreads to other sites, but a lot of
damage may occur, such as CNS dysfunction which
occurs in ~10 % of the cases and is due to an
unknown cause.
Secondary infections such as pneumonia and otitismedia are common.
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Bordetella
B. parapertussiscauses a mild form ofwhooping cough
B. bronchosepticaWidespread in animals where it causes
kennel cough.
Occasionally causes respiratory or wound
infections in humans.
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Bordetella
Treatment
Erythromyinonly effective in early stages of
the disease before the toxin(s) have beenreleased
Vaccination P part of DPT (killed, encapsulatedorganism); a subunit vaccine has also been
developed (purified pertussis toxin).
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BRUCELLA
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1. Brucellosis is considered as the most wide spreadzoonosis in the world and it is considered as True
zoonosis ( That mean it is Basically transmitted from
animal to human).
2. The importance of this contagious disease is the economic
impacton livestock industry.
3. Causes sever hazard to human health, through eitherdirect contact with infected animals or the consumption of
contaminated milk and dairy products.
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Causative bacteria of the disease
Brucellosisis named after Sir David Bruce, who is in 1886
isolated the causative agent from a soldier inMalta.
Brucella species are recognized based on the natural
animal hostto the following species as shown in table ( 1).
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Human
disease
Other animal
species affected
Natural
hostBiovarSpeciesNO
Less sever
Wild animals,
water buffalo,
camels
Cattle1-9Brucel la abortus1.
SeverWild ruminant
cattle, camels
Sheep
and Goat
1-3Brucel la meli tensis2.
NoneNoneSheep
(Ram)1Brucel la ovis3.
Sever
( except
biovar 2)
Various wild
speciesSwine1-5Brucel la suis4.
BenignNoneDog1Brucel la canis5.
NoneNoneWood rat1Brucel la neotomae6.
Table (1) show Brucella species :
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1. The bacteria are strictly parasitic and prefer theintracellular habit.
2. The species of the genus Brucella are small non
motile, non spore forming, Gram negative rodsand they do not produce true capsules.
3. They aresomewhat resistant to decolonization by
weak acids and thus stain red by the modified
Ziehl - Neelsen method.
Morphology and staining
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Gram stain of Brucella
(Gram ve ) Coccobacilli
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Antigenic Structure
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The designation of the antigens in cultures composed of smooth
and rough coloniesare shown in the table 2.
NO. Species Type of colony
Type of
surface antigen
1. Brucella abortus Smooth A m ---
2. Brucella melitensis Smooth a M ---
3. Brucella suis Smooth A m ---
4. Brucella ovis Rough --- --- R
5. Brucella canis Rough --- --- R
The Production of monospecific antiserato A and M antigen
can be used in the identification of the Brucella species.
Br.canis and Br.ovis grow as rough colonies that do not
possess either of the surface antigens Aand M, but instead of
that they have Rantigen.
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1.Culture media
There are two major types of media for cultivation of Brucella.A. Basal Medium
Direct isolation and culture of Brucella are usually performed on solidmedia.
This enables the developing colonies to be isolated and limit thedevelopment of contaminants.
There is many Kinds of commercial media ,e.g. Brucella medium base,Trypticase soy agar, Columbia agar, Serum- dextrose agar or Glycerol-dextrose agar.
The addition of 2-5 % Bovine or Equine serumis necessary for the growthof strains such as B. abortus biovar 2.
B. Selective Media
Appropriate antibiotics are added in order to suppress the growth oforganisms other than Brucella. The most widely used medium is Farrellsmedium, which is prepared by the addition of six antibiotics :
Polymyxin B sulphate,Bacitracin, Cycloheximide, Nalidixic acid, Nystatin,
Vancomycin
Cultural characteristics
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2. Colony Morphology
Brucella colonies are visible after 3-5 daysincubation period at 37 C on suitable solidmedia, and they are aerobic or microaerophilic.
Cultures should not be discarded as negativeuntil 8-10 days have elapsed.
Brucella colonies are 1-2 mm in diameter,round, entire, smooth, glistening, translucent,and a pale honey color when plates are viewedin the daylight through a transparent medium.
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Brucella colonies on blood agar
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Brucella colonies on blood agar
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Epidemiology of the disease
1.Transmission of the disease
Animal to animal Transmission
The oral route, Contamination of the udder during milking
and contact with aborted fetusesand infected newborn lambs
are considered to be common methods of spread, also thevenereal transmissionof the disease is occur due to infectedmale or contaminated semen.
Animal to human Transmission
Infected tissues, and contaminated materials must behandled under (biosafty 3)conditions. Transmission could beeither by contaminated food, invasion by intact skin,inhalation of aerosols containing the bacteria and aerosol
contamination of the conjunctiva.
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One of the most important route of animal to
human transmission of Brucella
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Brucella melitensis( biovar 1, 2 or 3) is the main
causative agent of caprine and ovine brucellosis.
Sporadiccases caused by B.abortus have been
observed. The infection is widespread world-wide.
Brucella abortus is usually causes bovine
brucellosis, less frequentlyby brucella melitensis.
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Brucellosis: Edema and swelling of scrotum
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