Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
37 Cards in this Set
- Front
- Back
|
Name 3 Gram neg rods that are acquired through the respiratory tract?
|
1. Haemophilus influenza
2. Bordetella pertussis 3. Legionella pneumophila |
|
|
What is Haemophilus influenzae?
|
Haemophilus means blood loving.
Requires blood containing medium for growth hematin found in blood is necessary for the bacteriums cytochrome system. Blood also has NAD+ needed for metabolic activity. It is an obligate human parasite transmitted via the respiratory route. |
|
|
How does H. influenzae cause disease/
|
A polysaccharide capsule confers virulence.
There are 6 types of capsules, designated a, b, c, d, e, f. of these, type b, is commonly associated with invasive H. influenzae disease in children, such as meningitis, epiglottitis and septic arthritis. |
|
|
Non encapsulated strains of H. influenzae can colonize the upper respiratory tract of children and adults. They lack virulent invasiveness and cause local infection only. TRUE/FALSE
|
TRUE. They often cause otitis media in children
|
|
|
Do children possess antibodies against the "b" capsule?
|
No. They lack antibodies between ages 6 months and 3 years . The mother does possess antibodies, which she will give to the fetus transplacentally, and through breast milk. It takes 3-5 yrs of H. influenzae colonization and infection for children to develop their own antibodies.
|
|
|
Haemophilus meningitis is the most serious infection caused by encapsulated H. influenzae type b. TRUE/FALSE
|
TRUE. Following inhalation, this organism invades the local lymph nodes and bloodstream and then penetrates into the meninges.
|
|
|
Is H. influenzae meningitis treatable.
|
Generally yes, but cautiously. When bacterial memningitis is treated with antibiotics, the killed bacteria lyse and release cellular antigens, such as LPS lipid A endotoxin resulting in a violent immune response that destroys neurons as well as bacteria. Steroids may limit inflammatory severity.
|
|
|
What is acute epiglottitis?
|
Caused by H. influenzae, it results in a severe swelling of the epiglottis, potentially obstructing the respiratory tract. The large red epiglottis looks like a cherry at the base of the tongue. Inspection of the larynx may cause laryngeal spasm. It is best to use an endotracheal tube for inspection.
|
|
|
Meningitis, epiglottitis and bacterial sepsis are rapidly fatal without antibiotic therapy. TRUE/FALSE
|
TRUE. Most strains are now resistant to ampicillin via plasmid transfer.
Cefotaxime and ceftriaxone are employed. Ampicillin and amoxicillin may be used for otitis media infections. |
|
|
Is there a vaccination protocol?
|
yes. A new vaccine is compose dof the H. influenzae type b(Hib) capsule and diptheria toxin. The addition of the diphtheria toxin activates T lymphocytes and antibodies against the b capsule. This is given to children at 2, 4, 6 and 15 months, along with DPT and polio vaccines.
|
|
|
What is Haemophilus ducreyi?
|
This species is responsible for the sexually transmitted disease "chancroid". patients present with a painful genital ulcer, with swollen inguinal lymphnodes. Lymphnodes will rupture releasing pus.
|
|
|
What is the differential diagnosis?
|
1. Syphilis-(Treponema pallidum). Ulcers of syphilis are non painful and produce no pus.
2. Herpes-Simplex 1 and 2. Herpes has systemic symptoms such as myalgia and fevers. Chancroid does not produce systemic sysmptoms. 3. Lymphogranuloma venereum(Chlamydia trachomatis), has painless suppurative lymphnodes that develop much more slowly than chancroid. |
|
|
How is chancroid treated?
|
Treat with erythromycin or trimethoprim/sulfamethoxazole.
|
|
|
What is Gardnerella vaginalis?
|
Was known as H. vaginalis. Causes bacterial vaginitis with anarobic vaginal bacteria. It is differentiated from other causes of vaginitis(such as candida or trichomonas, by examining a slide of the vaginal discharge for the presence of "Clue cells". These are vaginal epithelial cells that have tiny pleomorphic bacilli with the cytoplasm.
|
|
|
What is the therapeutic protocol/
|
Metronidazole.
|
|
|
What is Bordetella pertussis?
|
It means violent cough.
It is Gram neg. It has 4 major virulence factors, that attach to ciliated epithelial cells of the trachea and bronchi. Destrys ciliated cells. |
|
|
What is the pertussis toxin?
|
This toxin has a B subunit that binds to target cells receptors, allowing entry of the A subunit. The A (action) activates cell membrane bound G regulatory proteins, which activate adenylate cyclase. This results in an outpouring of cAMP, which activates protein kinase and other intracellular messengers.
|
|
|
What are the 3 observed effects of the pertussis toxin?
|
1. Histamine sensitization
2. Increase in insulin synthesis 3. promotion of lymphocyte production and in hibition of phagocytosis. |
|
|
What is the significance of the internalized adenylate cyclase.
|
It synthesizes cAMP resulting in impaired chemotaxis and impaired generation of H2O2 and superoxide
|
|
|
What is Filamentous hemagglutinin?
|
B. pertussis attches to ciliated epithelial cells of the bronchi and then releases its damaging exotoxins. Antibodies are directed against FHA and prevent binding and disease.
|
|
|
What is Bordetella pertussis?
|
It means violent cough.
It is Gram neg. It has 4 major virulence factors, that attach to ciliated epithelial cells of the trachea and bronchi. Destrys ciliated cells. |
|
|
What is the pertussis toxin?
|
This toxin has a B subunit that binds to target cells receptors, allowing entry of the A subunit. The A (action) activates cell membrane bound G regulatory proteins, which activate adenylate cyclase. This results in an outpouring of cAMP, which activates protein kinase and other intracellular messengers.
|
|
|
What is Bordetella pertussis?
|
It means violent cough.
It is Gram neg. It has 4 major virulence factors, that attach to ciliated epithelial cells of the trachea and bronchi. Destrys ciliated cells. |
|
|
What are the 3 observed effects of the pertussis toxin?
|
1. Histamine sensitization
2. Increase in insulin synthesis 3. promotion of lymphocyte production and in hibition of phagocytosis. |
|
|
What is the significance of the internalized adenylate cyclase.
|
It synthesizes cAMP resulting in impaired chemotaxis and impaired generation of H2O2 and superoxide
|
|
|
What is the pertussis toxin?
|
This toxin has a B subunit that binds to target cells receptors, allowing entry of the A subunit. The A (action) activates cell membrane bound G regulatory proteins, which activate adenylate cyclase. This results in an outpouring of cAMP, which activates protein kinase and other intracellular messengers.
|
|
|
What is Filamentous hemagglutinin?
|
B. pertussis attches to ciliated epithelial cells of the bronchi and then releases its damaging exotoxins. Antibodies are directed against FHA and prevent binding and disease.
|
|
|
What are the 3 observed effects of the pertussis toxin?
|
1. Histamine sensitization
2. Increase in insulin synthesis 3. promotion of lymphocyte production and in hibition of phagocytosis. |
|
|
What is the significance of the internalized adenylate cyclase.
|
It synthesizes cAMP resulting in impaired chemotaxis and impaired generation of H2O2 and superoxide
|
|
|
What is Filamentous hemagglutinin?
|
B. pertussis attches to ciliated epithelial cells of the bronchi and then releases its damaging exotoxins. Antibodies are directed against FHA and prevent binding and disease.
|
|
|
In whooping cough, a week long incubation period is followed by 3 stages of disease. What are they?
|
1. Catarrhal stage
2. Paroxysmal stage 3. Convalescent stage |
|
|
How is whooping cough cultured/
|
This organism will not grow on cotton. A calcium alginate swab is employed. It is then grown on Bordet-Gengou medium, or Elisa test.
|
|
|
What is the treatment?
|
Erythromycin.
|
|
|
What is legionella pneumophila?
|
It is an aerobic Gram neg rod that is famous for causing an outbreak of pneumonia at an American legion convention in Philadelphia in 1976.
It is ubiquitous in man made water environments. It can be inhaled(air conditioning systems, cooling towers and whirlpools, and shower heads. person-person transmission has not been demonstarted. |
|
|
LEGIONELLA IS A FACULTATIVE INTRACELLULAR PARASITE THAT SETTLES IN THE LOWER RESPIRATORY TRACT AND IS INGESTED BY MACROPHAGES. TRUE/FALSE
|
TRUE.
|
|
|
What is Pontiac fever?
|
Like influenza, this involves headache, muscle aches and fatigue followed by fever and chills. It resolves in less than 1 week.
|
|
|
What is the treatment protocol?
|
Erythromycin, because this organism has a beta lactamase making it resistant to penicillins.
|
