Unit 3: Gallibacterium, Haemophilus and Histophilus Flashcards
What has Gallibacterium anatis been incriminated in causing in chickens?
peritonitis
When working in combination with Escherichia coli, what can Gallibacterium anatis cause?
severe peritonitis
Generally, how would you describe the genus Haemophilus (gram stain, oxidase, growth)?
blood loving, small gram-negative rods, oxidase positive, and slow growing
What may the genus Haemophilus need to grow?
hemin, nicotine adenine dinucleotide, serum, or CO2
What does Haemophilus parasuis cause in swine?
Glasser’s disease - polyserositis, arthritis, and meningitis
What does Haemophilus parasuis require for growth?
NAD and serum
What type of colonies does Haemophilus parasuis have?
small translucent colonies that are non-hemolytic
What is the natural habitat of Haemophilus parasuis?
nasopharynx of many normal swine
How is Haemophilus parasuis transmitted?
by aerosol and contact
Haemophilus parasuis has been recovered from ______ in baby pigs but it may not be the cause of the _______.
pneumonias; pneumonia
What specifically does Haemophilus parasuis infections cause?
fibrinous inflammation of the pericardium, pleura, peritoneum, joints, and in severe cases, meninges
What clinical signs are associated with a Haemophilus parasuis infection?
swollen joints and lameness, bronchitis, pleuritis, peritonitis, and fever
What predisposes swine to infection by Haemophilus parasuis and what does it result in?
swine influenza or porcine reproductive and respiratory syndrome resulting in coughing, fever, lobular pneumonia, and occasional death
What is needed for Haemophilus parasuis colonies to grow?
Staph nurse
Are there vaccines against Haemophilus parasuis infection and if so are they helpful?
Yes, against serotypes 1,2,4, and 5 - autogenous and commercial bacterins as well as modified live vaccines
There is some success but this infection is still a problem in swine confinement facilities
How do you treat a Haemophilus parasuis infection?
Penecillin, Tetracycline, and tiamulin
What genera is Histophilus somni related to?
Pasteurella and Actinobacillus
What disease processes does Histophilus somni cause and in what species?
Thrombotic meningoencephalitis and respiratory disease primarily in feedlot cattle but it has been isolated from cases of septicemia, epididymitis, abortion, meningitis, vulvovaginitis, and mastitis in sheep
On gram stain, what does Histophilus somni look like?
gram negative small coccobacillus
On primary isolation, what does Histophilus somni require for growth?
CO2
Is Histophilus somni hemolytic?
no but many isolates produce a greening of the agar around the colonies
What is the habitat of Histophilus somni?
the upper respiratory tract of cattle and in the genital tract of male and female cattle
What toxins does Histophilus somni produce?
endotoxin and lipooligosaccharide (LOS)
What may be the roles of the LOS produced by Histophilus somni?
it may play a role in disease by inducing apoptosis of endothelial cells and may help the organism evade the host immune system
What other virulence factors does Histophilus somni have?
Adenine, guanine, GMP, Fc-receptor proteins
What is believed to be the function of adenine, guanine, and GMP released by Histophilus somni?
they are thought to aid in the intracellular survival of the organism by mitigating the oxidative burst
What enables the dissemination of Histophilus somni throughout the host’s body?
it is able to survive in blood monocytes
What is TME?
Thrombotic meningoencephalitis caused by Histophilus somni
When does TME typically occur in feedlot cattle?
2-4 weeks after shipping and often during periods of we, changeable fall weather
What is the route of infection of TME in feedlot cattle and what does it lead to?
Infection is via the respiratory tract leading to fibrinous meningitis with arterial thrombosis and necrosis
Clinically, what does one see with TME?
fever, anorexia, lameness, neurologic signs, weakness and somnolence
Histophilus somni can cause what in cows although it has not been recognized in the midwest?
abortion, infertility, and retained placenta
Is there natural immunity against Histophilus somni infection?
not exactly - if they recover from it then they have good immunity against it
Are there bacterins for Histophilus somni and are they effective?
There are bacterins but they are thought to only be the most effective against the clinical effects of TME and not the respiratory disease associated with this bacteria
How is Histophilus somni infection treated?
tetracycline, long-acting macrolides, and ceftiofur
__________ _________ was previously the second leading cause of bacterial meningitis in human infants.
Haemophilus influenzae
What does Haemophilus influenzae continue to be an important cause of?
cellulitis, bacteremia, otitis media, pyoarthrosis, acute exacerbations of chronic bronchitis, sinusitis, and community acquired respiratory tract infections
On gram stain, what does Haemophilus influenzae look like?
it is a gram negative rod that exhibits considerable pleomorphism
What is the most common capsular type of Haemophilus influenzae composed of?
a polyribitol phosphate that is very similar to the teichoic acids of gram-positives
Since the capsule of Haemophilus influenzae tends to not decolorize properly, what stain is recommended for this organism?
Carbol-fuchsin
What is the principle antigen of importance for Haemophilus influenzae?
the capsule
What is the most common capsule that Haemophilus influenzae has?
type b capsule (Hib)
Why are children under the age of 2 susceptible to Haemophilus influenzae infection?
because they do not generate a significant antibody response to the b capsular type even in the face of an infection
What other antigens are important in Haemophilus influenzae infection?
LOS and OMPs
What is the role of Haemophilus influenzae LOS toxin?
it is thought to contribute to the ability of the organism to produce invasive disease but its exact role is unknown
What is the pathogenesis of Haemophilus influenzae infection?
It is thought to initially colonize the nasopharynx and spread from there. The role of stress and concurrent disease such as viral infections is not understood
At what age do children typically get meningitis as a result of a Haemophilus influenzae infection and what preceeds it?
3 months to 6 years of age; preceded by respiratory signs for several days
How does acute epiglottitis present in a Haemophilus influenzae?
Clinical disease has an acute onset with a rapid course. Marked edema and abscessation of the epiglottis may occur - severely affected individuals may need a tracheostomy
What age individuals does acute epiglottitis occur in people infected with Haemophilus influenzae?
older children and adults
Where does cellulitis as the result of a haemophilus influenzae infection typically occur and how does it appear?
in the cheek and appears as the area of initial reddening and soreness that progresses to a dark purplish color
What age individuals typically get cellulitis as the result of a Haemophilus influenzae infection?
under 2 years of age
Bacteremia without local disease due to Haemophilus influenzae infection occurs in what percentage of individuals infected and at what age?
20% - 3 months to 3 years
Haemophilus influenzae is the second leading cause of _____ _______.
otitis media
True or False: The majority of isolates of Haemophilus influenzae involved in otitis media are type b.
False: they are untypable
What are newer vaccines against Haemophilus influenzae complexed with?
either a mutant diptheria toxin or the Neisseria meningitidis group B polysaccharide
