Microbiology Flashcards
What are commensal bacteria? `
They are basically the bacteria which act on host immune system and prevent pathogen colonization and invasion. `
How do commensal bacteria help to prevent infection?
They help by competing for nutrients and sites of adhesion, by producing products ( promote mucosal immunoglobulin production), and signals `
What are some of the normal colonizers of the the oropharynx and nasopharynx?
Group C or G streptococci, Group A Streptococcus, Strep. pneumoniae, H.Influenzae or Moraxella catarrhalis, N.Meningitidis
What age group does Strep. Pneumo affect?
6-100% of infants and toddlers, 25% of children ages 3 months to 4 years, 5-10% of older and younger people
What age group does Group A strep affect?
20% of children are colonized.
H. influenzae and Moraxellla Catarrhalis affects whom?
large percentage of infants and toddlers
N. Meningitidis affects mainly whom?
It affects mainly adolescents and toddlers. Coloniztion can lead to bacteremia, meningitis, or septic arthritis.
Streptococcus Aureus can cause ——-.
Can cause pneumonia (lower respiratory tract disease)
1/3rd of adults are colonized in their upper respiratory tracts and can cause serious disease.
Strep. Pneumo can cause
pneumonia
Enterobacteriaceae and non fermenting gram- negative bacilli can cause:
These are among the most common causes VAP.
Colonize URTI in children who have been in the ICU or frequent courses of antibiotics. Can become normal microbiota of ventilated children ICU.
Human rhinovirus aka RV can cause ——.
Is the most prevalent cause of virus induced ——-.
Virus induced asthma attacks.
Most common cause of the common cold. RV infections
What demographic does HRV cause common cold in?
Infection rates among young children can be as high as 8-12 times a year.
What are RV infections are often linked to :
acute otitis media and rhinosinusitis
What is the optimal temperature of RV replication?
32-33 C (cooler temps of the URTI)
Unable to replicate in the GI tract.
What upper respiratory tract diseases including:
Pneumonia, bronchitis, bronchiolitis, and exacerbation.
RVs exacerbate asthma attacks by what percentage?
What other conditions can RVs exacerbate?
50-85% of asthma exacerbations.
CF and COPD
RV is transmitted how?
Inhalation of infectious droplets, direct contact is major route and fomites.
RV Virus survives how long? How is control of RV virus?
Few hours to 4 days on non-porous surfaces, for atleast 2 hours on human skin.
With adequate hand hygiene cleaning surfaces
What is the mechanism behind rhinovirus infection?
Host cell ICAM-1 attaches to the canyon of the virus capsid.
VP1 is the viral attachment protein (immune system responds to a 20 AA stretch in the VP-1 protein)
When is VP-1 20 monomer epitope exposed?
After VP-1 binds to ICAM-1. This is how RV avoids immune system and causes recurrent immune infections.
What is a respiratory viral panel?
It is basically a tests that can identify what resp. viral infection you have.
20 viruses can be identified.
What main viruses can Respiratory viral panels test for?
Influenza A and B, Respiratory Syncytuial virus, human mela-pneumovirus, rhinovirus, human bocavirus, coronavirus, and adenovirus
What are two other conditions that RV virus is linked to other than cold?
Otitis media and rhinosinusistis
What is otitis media?
Inflammation of the middle ear