Bacterial Diseases Flashcards
Where would you expect not to find bacteria?
- Liver
- Gall bladder
- Pancreas
- Bladder
- Trachea
- Lungs
- Heart, brain, spleen
- Kidney
What type of bacteria do you find in the small intestine?
Gram-negative
Give some examples of bacteria and viruses that use the upper respiratory tract as a portal of entry.
Viruses:
- influenza
- parainfluenza
- rhinoviruses (common cold)
- Measles
- varicella
- other herpes viruses (HSV, EBV)
Bacteria:
- Streptococcus pneumoniae
- streptococcus pyogenes
- neisseria meningitidis
- staphylococcus aureus (MRSA and MSSA)
Give some examples of intrinsic bacteria that can infect via the urogenital tract.
E. coli
Klebsiella
Candida
Give some examples of extrinsic bacteria that can infect via the urogenital tract.
Chlamydia trachomatis, Syphillis (treponema pallidum) ,
Neisseria gonorrheae ,
HIV/HSV
Give examples of bacteria that can infect via broken skin.
Staphylococcus aureus Streptococcus pyogenes
State some consequences of infection via broken skin.
- Abscess formation (pus filled pocket)-Bacteraemia
- Necrotic infection (cell death underneath the superfificial layer)
- Myositis ( infections spread deeper into the muscle and causes inflammation)
What is it called when infection spreads across the skin layer?
CELLULITIS
Give some examples of bacteria( and the conseqences) and viruses that infect via the gastrointestinal tract.
Viruses:
- Hepatitis A
- Norovirus
- Hep E
Bacteria:
- E.coli (diarrhoea)
- Campylobacter jejuni (food poisoning)
- shigella ( dysentry)
- Vubrio cholerae (cholera)
- salmonella enterica (food poisoning)
- salmonella typhi (typhoid)
- Listeria monocytogenes
- clostridium difficile
What are some consequences of infection via the gastro-intestinal tract?
Diarrhoea
Bacteraemia/systemic infections : typhoid, listeriosis, salmonellosis
What two main factors affect pathogenecity?
Infectivity and Virulence
Define infectivity
and the factors involved.
The ability of a pathogen to establish
infection:
- transmission to host
-ability to colonise host
- Tropism: find unique niche (in or outside cells)
-Replicate
-immune evasion at site of colonisation or niche
Define virulence and the factors involved.
The features that enhance disease causation/ the disease producing ability of a microorganism:
- toxin
- enzymes that degrade host molecules
- interruption of normal host processes
- complete immune evasion
Define infectious dose and the factors that affect it?
Number of bacteria needed to initate an infection.
Factors:
- route of transmission (stomach acid means higher infectious dose is required)
- ability to colonise host
-tropism and motility
-replication speed
-Immune evasion at site
How can the infectious dose be lowered>
-if the pathogen can kill or subvert phagocytes
Describe how vibrio cholerae causes disease.
- HUGE INFECTIVE DOSE
- uses flagella to propel itself into the mucosal membrane of the intestines. It then begins producing toxins A and B, which bind to GM gangliosides and triggers production of cAMP This leads to chloride efflux and hence movement of water and sodium into the lumen from the cells
What is the clinical feature of vibrio cholera
Profuse diarrhoea - rice water stools
State gram negavtive pathogens and gram positive pathogens
Gram Negative:
- Neisseria ( meningitidis and gonorrhoeae)
- Haemophilus influenzae
- E. Coli
- Salmonella
- vibrio cholera
- shigella
Gram Positive:
- staphylococcus aureus
- Streptococcus
- clostridium
- Listeria
Which pathogen is a major skin pathogen
Staphylococcus Aureus
Give two examples of Gram-negative opportunistic bacteria.
Pseudomonas aeruginosa( multiple UTs treated with antibiotic)Acinetobacter baumanii (open trauma heavy prophylaxis)
Give two examples of Gram-positive opportunistic bacteria.
Enterococcus faecalis (abnormal heart valves) Staphylococcus epidermidis (e.g prosthetic joint and valve infections)
