Haemophilius Influenzae Flashcards
What are the characteristics H. Influenzae
Blood loving, gram-negative coccobacillus. It has a diverse shape types; long and single circular shape. H. Influenzae is the only organism that requires Haem (factor X found in blood) and NAD (V), in literature it will say they are X/V dependent.
Where does the bacteria primarily reside in the body?
H. influenzae normally lives in the nasopharynx area
Name the 3 disease and symptoms cause by Haemophilus Influenzae Type B (Hib)?
Meningitis: Organisms in the Cerebral spinal fluid (CSF) which infect the meninges causing inflammation. -Symptoms: Fever, vomit, loss of appetite, drowsy and unresponsive, rapid breathing, moaning, pale and blotchy skin with red rashes, bulging soft spot on head, stiff neck, dislike lights.
Epiglottitis: This is where the organism infects the epiglottis; causing inflammation and swelling of the epiglottis.-Symptoms: sore throat, difficulty and pain when swallowing, difficulty in breathing and sounds abnormal, fever, restless,muffled voice.
Pneumonia: Inflammation of the tissue in one or both of your lungs and causes an accumulation of fluid in the alveoli.-Symptoms: Difficulty in breathing (rapid and shallow), breathless,rapid heartbeat, fever, sweating and shivering and chest pains.
Which groups are most at risk?
Asplenic (spleen removed)
Complement deficiencies (C1-4); complement is very important for this disease
Aged 5 years and under; in particular, those who are in their 1st year of life.
What is the hallmark capsule of HiB called?
The capsule is called poly-ribosylribitol phosphate (PRP), this is the hallmark of Hib.
What are the type of Heamophilus influenza?
There are 6 serotypes with 1 none-typing category.
How does the capsule hetrogenicity arise?
There are many capsule, this is due to the genetics, the way the capsule locus is set up means that it can have multiple copied of the capsule locus.
A single bacterium with many copied of the capsule locus means that it will produce many capsules, the more loci it has, the more capsule is produced. Usually patients will have strain that have 6-7 repeated capsule units.
Why is the Hib capsule important?
Hib capsule is important as it has to do with complement membrane attack complex which will cause lysis and opsonisation; C3b causes this. IgG and C3b are known as opsonins and the process of attachment is called opsonisation.-Capsule can reduce the complement membrane attack complex and inhibits C3b deposition and therefore preventing opsonisation and bacterial phagocytosis.
What disease does Non-Typable H. influenzae (NTHI) cause?
Otis Media: infection of the middle ear-COPD: condition is to describe: emphysema and chronic bronchitis-Neonatal Invasive NTHI: Early onset neonatal NTHI disease is strongly associated with premature birth, septicaemia and meningitis pneumonia
Describe the Vaccine Approaches to Prevent H. influenzae Infection?
conjugate vaccines came in, it would produce an immune response in children from 2months+ of age, which hits the high risk group
How does it evade immune system
Capsules to inhibit phagocytosis
Antibody degrading enzymes
(IgA)
Inhibit complement
How can you treat?
Vaccine - PRP vaccine, use surface antigen of protein
Antibiotics - penicillin, ampicillin, methicillin
