L3 Systematic bacteriology 2 Flashcards
Give examples of gram negative prokaryotic pathogens?
Neisseria SPP
Escheria spp
Gram positive bacteria examples?
Streptococcus spp
Saphylococcus spp
enterococcus spp
clostridium
What are the gut commensal coliforms made of?
- E.coli
- Klebsiella spp
- Enterobacter spp
- proteus spp
What are the significant gut pathogens?
Salmonella spp
shigella spp
verotoxin producing e.coli (e.coli 0157, e.coli 0154)
The coliform term means?
describes species that look like e.coli on gram film and when cultured on blood agar
What is the first line antibiotic used for treatment of infection using coliforms?
Gentamicin
Why do patients with coliform sepsis become unwell quickly?
because of the endotoxin released from the gram negative cell wall when the bacteria dies
What is the underlying steps in fever production?
1-antigen/lipopolysaccharide (endotoxin) interact with macrophages
2-
macrophages release cytokines into the blood stream
3-
cytokines travel to the anterior hypothalamus brain
4-cytokines also stimulate the adverse effects of sepsis
5- prostoglandin E is released which increases the bodies thermal set point
6-the body perceives that it is cold and shivers to conserve heat
7-fever leads to increased survival from infection
How does SEPSIS lead to increased risk of haemorrhage?
1-small blood vessels become leaky and lose fluid in to the tissue
2- due to this the heart needs to put harder to allow more oxygen flow around body
3-poor perfusion of oxygen causes skin liver and kidneys to dysfunction
4-increased clotting factors causes clots in tiny vessels leading to an increased risk of haemorrhage
Give examples of gram positive pathogens?
- streptoccus
- enterococcus
What are the different results for classification of streptococci using haemolysis?
alpha-partial haemolysis
-caused by enzymes that denature the haemoglobin inside red blood cells causing greenish discolouration round the colony
beta- haemolysis=complete haemolysis
-caused by enzymes that lyse red blood cells causing complete clearing round the colony. the most pathogenic streptococci are beta
gamma-
no haemolysis
What is pneumnia?
An acute inflammation of the lungs, often caused by inhaled pneumococci of the species streptococcus pneumonia. the alveoli and bronchiles of the lung become plugged with a fibrous exudate
What sort of bacteria is streptococcus pneumonia?
- gram positive alpha haemolytic cocci-short chains or pairs
- part of normal upper respiratory tract flora in many people
- common cause of pneumonia
is enterococci haemolytic or not?
non-haemolytic
What does non-haemolytic streptococci commonly cause?
urinary tract infection
tell me 5 facts about staphylococci?
gram +ve
irregular grape like clusters
non-motile
types include s aureas (+ve) and s.epidermis(-ve)
facts about s.aureas?
- commonest cause of skin, soft tissue and wound infection
- common case of bone and joint infection
- food poisoning
tell me three facts about clostridium spp?
gram positive anaerobic bacilli
produces spores that can survive outside the body for many months
produces exotoxins that cause severe tissue damage-clostridium difficile- causes antibiotics associated diarrhoea esp in the elderly
