Satellite Phenomenon Of Haemophilus Influenzae Around Staphilococcus Aureus In Blood Agar

That cell specialization…it’s pretty important.

(From our video)

Elek test to document toxi production of Corynobacterium diphteriae

Normal Flora

Blood, Spinal Fluid, Urine: sterile

Cutaneous surfaces (urethra, outer ear included): Staph epidermidis, Staph aureus, Corynobacteria (dyphteroids),Streptocci, Candida spp

Nose: Staph aureus, Staph epidermidis, dyphteroids, assorted streptococci

Gingival crevices: anaerobes = Bacterioides/Prevotella, Fusobacterium, Streotococci, Actinomyces

Oropharynx: Viridans group (alpha hemolytic strep), Neisseria (non pathogenic), H. influenzae (non typeable, meaning, w/o capsule), Candida albicans

Stomach: none

Breast-fed babies colon: microaerophilic/anaerobic = Bifidobacterium, Lactobacillus, streptococci.

Adult Colon: microaerophilic/anaerobic = Bacteroides/Prevotella, E.coli, Bifidobacterium, Eubacterium, Fusobacterium, Gram- anaerobic rods, Lactobacillus, E.faecalis, streptococci

Vagina: Lactobacillus, streptococci, diphteroids, yeasts, Veillonella, Gram- rods

20 09 18

i feel as though i haven’t been as active these past couple of days. uni and work just drained the life out of me and i haven’t done anything but lay in bed when getting home.

on the bright side, i did force myself to get up and clean my room. so here are some low-light pics of my bedroom :)

Haematology

White Blood Cells (Leukocytes)

Neutrophils, eosinophils and basophils = granulocytes (polymorphonuclear leukocytes)

Monocytes & lymphocyes = mononuclear

Neutrophils

Most numerous (~60% of WBC)

Nucleus divided into lobes

Cytoplasm contains small granules

Stains pink with Romanowsky dyes

Lifespan of 6-10hrs

Exit into tissues - non-specific defence against bacteria and fungi

Eosinophils

1% of circulating leukocytes 

Large cytoplasmic granules - stain strongly with acidic dye eosin

Nucleus is bilobed

Circulate for 4-5hrs

Exit to tissues –> 

Defence against parasites 

Dampen allergic response

Tissue eosinophils are also capable of responding to bacterial and fungal infection in a similar way to neutrophils.

Basophils

Least numerous (<1%)

Large granules stain strongly with basic dye methylene blue

Involved in anaphylactic hypersensitivity and inflammatory reactions

Monocytes

5% of circulating leukocytes

Large cell

Kidney/clefted shaped nucleus

Scattering of delicate azurophilic granules

Circulate for 10hrs

Mature into phagocytic tissue macrophages

Responsible for the removal of aged RBCs and other debris

Process and present antigens to T-lymphocytes 

(Macrophages are formed in response to an infection or accumulating damaged or dead cells. Large, specialized cells that recognize, engulf and destroy target cells.)

Lymphocytes

Second most common leukocyte (33%)

Much less cytoplasm - nucleus almost fills cell

Variable lifespan

Receptors on surface recognise foreign substances

Several types of lymphocyte - click here

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

Amazing web site!

Medically Important Bacteria: Clasification

Listeria with tumbling motility (by Pathmass)

Listeria monocytogenes

Gram+, aerobic, motile rod, facultative intracellular, beta hemolytic on blood agar

Tumbling motility in broth (as seen in video)

Jet motility in cells by actin filament formation

Listeriolysin O (Beta hemolysin): pathogenic factor, facilitates it scape from phagosome before phagolysosome formation and “jets” into another cell.

Diseases:

Lysteriosis: asymptomatic or diarrhea. 

Lysteriosis in pregnant women septicimia, crosses placenta.

Granulomatosis infantisepticum: neonatal disease, in utero transmission, sepsis, diseminated granulomas and high mortality.

Neonatal sepsis and meningitis (3° most common cause) 2-3 weeks after birth (fecal exposure)

Septicemia and meningitis in immunocompromised pts

Meningitis in renal transplant pts, cancer pts

A sample of notes from Medical Virology // I keep the margins empty so that I have space to add in relevant additional material from extra reading