This One’s About Bugs

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Leukocyes (WBCs) & Defence

A summary

Neutrophils -  non-specific defence against bacteria and fungi

Eosinophils -Defence against parasites; dampen allergic response

Basophils  - Anaphylactic & inflammation response

Monocytes - Mature into macrophages, engulf foreign substances;  remove aged RBCs and other debris

Lymphocyes - Recognise antigens, various roles

Without immunity, we’RE JUST BAGS OF NUTRIENTS!

Microbiology lecturer (via scienceprofessorquotes)

Clostridium tetani

Gram+, anaerobe, spore forming, motile, rod.

Neurotoxin: Tetanus Toxin blocks glycine and GABA and produces a SPASTIC PARALYSIS.

TETANUS

Opisthotonus

Risus  Sardonicus

Severe mucle spasm

Mycobaterium tuberculosis PATHOGENESIS

Facultative intracellular

Sulfatides: inhibit PHAGOLYSOSOME FORMATION allowing intracellular survival.

Cord Factor (serpentine growth in vitro): disrupts mithochondrial respiration and oxidative phosphorilation and inhibits leukocyte migration.

Tuberculin + Mycolic Acid: type IV hypersensitivity (delayed hs), Cellular Mediated Immunity (CMI)

Medically Important Fungi

Difference between Blood Agar and Chocolate Agar

Hi everyone!

I’ll tell you in short about Nutrient agar first

It is a simple basal medium used for growth of common pathogens

It constitutes peptone water, meat extract and agar

Difference between Blood Agar and Chocolate Agar

What is common between Blood agar and Chocolate agar?

Both are enriched media

Used for the growth of Gram positive cocci and fastidious organisms like Neisseria & Haemophilus species

Can be used to indicate hemolysis

What are fastidious organisms?

They require specialized environments due to complex nutritional requirement

What is the difference between Blood agar and Chocolate agar?

The difference lies in how the media are made

How is Blood agar made?

Nutrient agar is sterilized by autoclave, cooled to 50°C and sterile sheep blood (5-10%) is added gradually and poured into plates

How is Chocolate agar made?

Nutrient agar is sterilized by autoclave, cooled to 75-80°C and sterile sheep blood (5-10%) is added gradually and poured into plates

How is the difference in temperature significant?

Certain organisms such as Haemophilus species require V factor for growth (complex nutritional requirement)

Factor V is present in blood but it is present inside the red blood cells (RBC)

These organisms can not utilize V factor which is trapped inside the RBC’s in Blood agar

When Blood agar is heated to 80-90°C for a few minutes (boiled blood agar), the V factor is released from within the erythrocytes and made available to the organism for utilization

Some strains of Neisseriae and Diphtheroids require V factor too

That’s why these media are superior to plain Blood agar for growing organisms requiring V factor

What is V fatcor?

V fatcor is a coenzyme, Nicotinamide Adenine Dinucleotide (NAD) or Nicotinamide Adenine Dinucleotide Phosphate (NADP) which acts as a hydrogen acceptor in the metabolism of cell

So to conclude, Chocolate agar is a type of blood agar in which the blood cells have been lysed by heating for growing fastidious organisms :)

Did you know?

Modified Thayer Martin is a type of chocolate agar which contains antibiotics (Vancomycin, Nystatin & Colistin) to suppress growth of other bacteria and promote growth of  N gonorrhoeae

*phew* That’s all for today!

The image is my first photoshop work on the site, hope you like it =D

Just to remind you guys, Chocolate agar contains no chocolate, they simply named it after the yummy color :P

-IkaN

 30 . 06 . 2017  Microbiology notes !!!  Yesterday I took my physics final exam and it went great: I got a 27/30, which is way more than what I expected as Physics is one of my worst subjects.  My next exam, microbiology, is in four days and I’m starting to feel a bit anxious about it as it’s a pretty tough exam but I’ll try to do my best ! 

Strep throat.