Microbiology Flashcards
Name the common intracellular bacteria?
Rickettsia
Chlamydia
Coxiella
What bacteria can grow on artificial media but have no cell wall?
Mycoplasm
Ureaplasma
Name the common spirochates?
Treponema
Leptospira
Borrella
Name the common gram negative cocci?
Neisseria
Moraxella
Veillonella
Name the anaerobic gram positive cocci?
Peptostreptococcus
What type of bacteria are aerobic gram positive cocci in clusters?
Staphlococcus
Are staphlococci catalase positive or negative?
Positive
What type of bacteria are aerobic gram positive cocci in chains?
Streptococcus
Are streptococci catalase positive or negative?
Negative
Name an alpha-haemolytic gram positive cocci chain that is optochin sensitive?
Streptococcus pneumoniae
Name an alpha-haemolytic gram positive cocci chain that isn’t optochin sensitive?
Viridans group streptococci
What type of bacteria are aerobic gram positive cocci in clusters?
Staphlococcus
Name a beta-haemolytic gram positive cocci chain?
Group A Strep (S. pyogenes)
Group B Strep (S. agalactiae)
Group G Strep ( S. dysgalactiae)
Name a non-haemolytic gram positive cocci chain?
Group D Strep (S. bovis, Enterococcus spp.)
Name a coagulase positive gram positive cocci in clusters?
Staphlococcus aureus
Name a coagulase negative gram positive cocci in clusters?
Staphlococcus epidermidis
Staphlococcus saprophiticus
Name a gram positive aerobic rod?
Corynebacterium
Listeria
Bacillus
Name a gram positive anaerobic rod?
Clostridium
Propionibacterium
Name a gram negative aerobic rod that is a lactose fermenter?
Escherichia
Klebsiella
Name a gram negative aerobic rod that is not a lactose fermenter?
Salmonella
Shigella
Proteus
Pseudomonas (it is oxidase positive)
Name a gram negative aerobic rod that is not a lactose fermenter or lactose fermenter?
Vibrio Camplyobacter Helicobacter Haemophilus Bordatella Legionella
Name a gram negative anaerobic rod?
Bacteroides
What are Zeihl-Neelsen/Acid fast positive?
Mycobacteria - rods
Name some MTB complex Ziehl-Neelsen positive?
Mycobacterium tuberculosis
Mycobacterium bovis
Mycobacterium africanum
Name some non-tuberculous mycobacterium Ziehl-Neelsen positive?
Mycobacterium avium Mycobacterium kansasii Mycobacterium marinum Mycobacterium ulcerans Mycobacterium fortuitum etc.
Name a Ziehl-Neelsen positive non-cultivable?
Mycobacterium leprae
What colour is a stained gram positive?
Purple
What colour is a stained gram negative?
Pink
How would you carry out a gram stain?
Fixation –> crystal violet stain –> iodine treatment –> decolourisation –> counter stain (safranin)
In what year was the great plague of London?
1334 spread from China
In what year was the Mexico smallpox epidemic?
1519
In what year was the great flu epidemic?
1918
In what year was HIV identified?
1984
In what year was severe acute respiratory syndrome (SARS) identified?
2003
When was the global H1N1 flu pandemic?
2009
Swine flu, type A influenza
What is a pathogen?
An organism that causes or is capable of causing disease
What is a commensal?
An organism which colonises the host but causes no disease in normal circumstances/
What is an opportunistic pathogen?
A microbe that only causes disease if host defences are compromised.
What is virulence/pathogenicity/
The degree to which a given organism is pathogenic.
What is asymptomatic carriage?
When a pathogen is carried harmlessly at a tissue site where it causes no disease.
What is the difference between gram positive and gram negative bacteria?
Gram negative have two membranes (inner and outer) while gram positive only have the outer.
Gram positive have much more peptidoglycan.
What is endotoxin?
Component of the outer membrane of bacterial eg. lipopolysaccharide in gram negative bacteria
What is exotoxin?
Secreted proteins of gram positive and gram negative bacteria.
Compare endo and exotoxin?
Composition: Exo - protein. Endo - lipopolysaccharide Action: Exo = specific. Endo = non-specific Heat effect: Exo = labile. Endo = stable Antigenicity: Exo = strong. Endo = weak Produced by: Exo = gram positive mostly. Endo = LPS gram negative Converted to toxoid: Exo = yes. Endo = no
What are the 3 types of gene transfer in bacteria?
Transformation eg. via plasmid
Transduction eg. via phage
Conjugation eg. via sex pilus
What is haemolysis?
Ability of bacteria to break down RBCs in blood agar - requires expression of hemolysin.
What is alpha haemolysis and how does it present?
Caused by production of hydrogen peroxide oxidising haemoglobin to methemoglobin. Agar apears green.
What is beta haemolysis and how does it present?
Lysis of RBS by hemolysin. Large clear areas around the bacteria.
What is gamma haemolysis?
No haemolysis.
