Pbl 1Pod1 – first year

asem shadid

1. Describe the morphology of cooci and its effect on the body .

2. Describe Diagnostic test for streptococci infection :-

Microscopy – general blood test – gram sating - blood culture – esr – aso titer – crp.

3. Describe the acute inflammation and it courses .

4. Describe the physical changes acute inflammation and systemic manifestation .

5 . Explain the mechanism of necrosis

Objective :

Single celled organisms

Very small

Need a microscope to see

Can be found on most materials and surfaces◦ Billions on and in your body right now

What are bacteria?

Three basic shapes◦ Rod shaped called bacilli (buh-sill-eye)◦ Round shaped called cocci (cox-eye)◦ Spiral shaped

Some exist as single cells, others cluster together

Bacteria are ALIVE!◦ They reproduce (make more of themselves)

◦ They need to eat

What do they look like?

Bacilli

Spiral

Cocci

Cluster of cocci

the morphology of cooci and its effect on the body

Staphylococcus aureus it is a common cause of skin infections (e.g. boils), respiratory disease (e.g. sinusitis), and food poisoning.

streptococcal infection in adults, infection is normally associated with pregnancy, or with comorbidities that predispose to infection, such as diabetes

Streptococcus

Cocci groupings

Coccus

Diplococcus

Streptococcus

Tetrad

Sarcinae

Staphylococcus

1. Describe Diagnostic test for streptococci infection :- Microscopy

A throat culture is a test to check for a bacterial or fungal infection in the throat. A sample from the throat is collected by swabbing the throat and placing the sample into a special cup (culture) that allows infections to grow

• If an infection grows, the culture is positive.

• If no infection grows, the culture is negative.

Culture

Deliberate growing of cells, especially microorganisms, in a solid or liquid medium (e.g. agar, gelatin), as of bacteria in a Petri dish

Why It Is Done

• A throat culture may be done to:

• Find the cause of a sore throat.

• Finding the organism that is causing the infection can guide treatment.

• Most sore throat infections are caused by a virus. A throat culture shows the difference between a bacterial infection and a viral infection.

• A negative throat culture may mean that the cause of your infection is a virus, rather than bacteria or fungus.

• A positive throat culture may mean Bacteria grows in the culture. Some bacterial throat infections include Strep throat .

The Gram staining

The Gram staining method, named after Hans Christian Gram.

the Gram's method are commonly classified as Gram-positive and Gram negative.

Others that are not stained by crystal violet are referred to as Gram negative, and appear red.

A Gram stain and culture of the material from an infected site are the most commonly performed microbiology tests used to identify the cause of a bacterial infection.

After culture a Gram stain is performed to help determine the type of bacteria present and to help determine what other tests may need to be performed to definitively identify the cause of infection.

Viruses cannot be detected with a Gram stain.

Antistreptolysin O titer (general blood test )

1. A blood sample is needed.

2. You should not eat for 6 hours before the test.

3. This test is done if you have symptoms of a previous infection by group A Streptococcus. Some illnesses caused by this bacteria are

• Scarlet fever

• Strep throat

A negative test result means you have likely not had a recent strep infection.

An abnormal or positive test means you recently had a strep infection, even if you had no symptoms. The ASO test may stay positive

C-Reactive Protein

Also known as: CRPFormal name: C-Reactive Protein

C-reactive protein (CRP) is a protein found in the blood plasma, the levels of which rise in response to inflammation.

C-reactive protein (CRP) is a non-specific test. It is used by a doctor to detect inflammation if there is a high suspicion of tissue injury or infection somewhere in the body, but the test cannot tell where the inflammation is or what condition is causing it.

CRP may sometimes be ordered along with an Erythrocyte Sedimentation Rate (ESR), another test that detects inflammation. While the CRP test is not specific enough to diagnose a particular disease

• The erythrocyte sedimentation rate (ESR) test will also be increased in the presence of inflammation; however, CRP increases sooner and then decreases more rapidly than the ESR.

ESRAlso known as: Sed Rate; Sedimentation Rate; Westergren Sedimentation RateFormal name: Erythrocyte Sedimentation Rate

• The erythrocyte sedimentation rate (ESR) the rate at which red blood cells sediment - تترسب -in a period of one hour.

• non-specific test that has been used for many years to help detect inflammation

• indicates the presence of inflammation but does not tell the health practitioner exactly where the inflammation is in the body or what is causing it.

• A low ESR can be seen with • a high red blood cell count (polycythemia)• high white blood cell count (leukocytosis)• Some changes in red cell shape (such as sickle cells in sickle cell

anemia) also lower the ESR.

Inflammation is divided into acute inflammation, which occurs over seconds, minutes, hours, and days, and chronic inflammation, which occurs over longer times.

Acute inflammation begins within seconds to minutes following the injury of tissues. The damage may be purely physical, or it may involve the activation of an immune response. Three main processes occur:Increased blood flowIncreased permeabilityMigration of neutrophils

3. Describe the acute inflammation and it courses .

5 . Explain the mechanism of necrosis

Necrosis is a form of cell injury that results in the premature death of cells in living tissue by autolysis .

In contrast, apoptosis is a naturally occurring programmed and targeted cause of cellular death. apoptosis often provides nice effects to the organism, necrosis is almost always bad and can be fatal ( lead to death )

Thank you

asem shadid