Infection 1 Flashcards
What are the 3 modes of horizontal transmission?
Contact
Inhalation
Ingestion
What is a vector?
An intermediate in the transmission of a micro- organism
What is an example of vertical transmission?
Mother to child during child birth or during pregnancy
Describe the journey of transmission (5 steps)
Exposure Adherence Invasion Multiplication Dissemination
What happens once the microorganism enters the body system?
Exotoxins are released (chemicals)
And endotoxins are recognized by the body
Name some exotoxins
- cytolytic
- AB toxins
- Superantigens
- enzymes
What questions would you ask a patient with a suspected infection?
Symptoms - focal/systemic, severity, duration
What is infection?
Invasion of host tissues by microorganisms caused by microbial multiplication, toxins and host response.
What is an exotoxin?
A chemical released by a microorganism into the local environment
What would you be looking for on examination of a patient with an infection?
Organ dysfunction
What SUPPORTIVE investigations would you carry out on a patient with a suspected infection?
Full blood count (neutrophils and lymphocytes)
C-reactive protein (CRP) measure of inflammation
Blood chemistry (liver and kidney function)
Imaging (X-ray)
What SPECIFIC tests would you carry out on a patient with a suspected infection?
Bacteriology - Specimen types =swabs, fluids and tissues
Microscopy , Culture and Susceptibility - bacterial cells and cerebrospinal fluid.
Antigen detection
Virology - antigen detection, antibody detection
What is contained within the MICROBIAL world?
Viruses, bacteria, parasites and fungi
How are viruses classified?
Baltimore scale 1-7
What is the difference between enveloped and unenveloped in terms of ability to sterilise?
Enveloped are easier to destroy as the envelope can be punctured
Out of RNA or DNA viruses which are more likely to mutate?
RNA is less stable so more likely to mutate
What are bacteriophages?
Viruses that infect bacteria
What are aerobes?
Bacteria that can survive in oxygen
What are obligate aerobes?
Bacteria that require oxygen to survive
What are anaerobes?
Can survive in the absence of oxygen
What is an Obligate anaerobe?
Bacteria that requires oxygen to survive
What shape is staphylococcus?
Cluster (like grapes!)
What is the shape of streptococcus?
Rod like
Coccus= ? Bacilli = ? Spiralus = ?
Coccus= ball Bacilli = rod Spiralus = spiral
State and give examples of the mechanism of bacterial entry into hosts?
Host entry (via polysaccharide capsule)
Adherence to host cells (pilli)
Invasiveness (collagenase)
What is clostridium difficile?
- gram-positive bacteria
- anaerobic
- motile
What does infection of C.difficile lead to?
Colitis (inflammation of colon) leads to infectious diarrhoea.
C.difficile produces enterotoxin and cytotoxin which cause the diarrhoea.
What is the difference between yeast and mold?
Yeast = single cell Mold = multicellular
What happens after inhalation of streptococcus pneumonie?
Inflammatory response
Vasodilation - exudate of fluid
Fever, pain, redness, loss of function
Bacteria are phagocytosed by neutrophils
