Pyogenic Infections

Problem 1

Problem ^_^• A patient was brought to the hospital in coma.• Clinical Examination showed that the patient: - Was comatose - Had high temperature - Had stiff neck & back • The doctor in charge put a provisional diagnosis

of infection with a pyogenic coccus.

Cocci that cause pyogenic infections (-_-) 1. Staphylococci : a. S.aureus (coagulase +ive )b. S.epidermidis (coagulase –ive)c. S.saprophyticus (coagulase –ive)

2. Streptococci :a. S.pyogenes b. S.pneumoniae (Pneumococcus)c. S.aglactiae d. Viridance Streptococci :• S.mutans• S.sanguis• S.mitis• S.salivarus e. Enterococci :• Enterococcus faecalis • Enterococcus faecium

3. Neisseria :• Neisseria meningitides (Meningococcus)• Neisseria gonorrhea (Gonococcus)

Gram positive

Gram negative

Diseases that are caused by pyogenic cocci (O_o)

• Skin infection (e.g.. Folliculitis , Cellulitis, Impetigo )• Septic Arthritis - infection of joints -• Septicemia - bacteria in blood -• Endocarditis - infection of heart valves - • Pneumonia - infection of lungs -• Food Poisoning • Scalded skin syndrome • Toxic shock syndrome • Osteomyelitis - disease of growing bones -• Urinary tract infection (UTI)• Tonsillitis & Pharyngitis• Sinusitis - nasal infection -• Otitis - ear infection -• Meningitis - infection of the meninges -• Brain abscess - collection of pus in brain -• Dental caries - tooth infection -• Gonorrhea

Probable diagnosis• Because of the stiffness of the neck & back which

is due to inflammation of the meninges (membrane covering the brain) , so we probably think its Meningitis

• In fulminant cases it may cause coma and death

Pyogenic cocci that cause such a disease :O• Pneumococcus • Meningicoccus • S.aglactiae

What are the specimens that you take for laboratory diagnosis of this patient?

1- CSF .•Cerebrospinal fluid (CSF) is the fluid that surrounds the brain and spinal cord.(PiaArachnoid space).•CSF acts as a cushion, protecting the brain and spine from injury. •The fluid is normally clear.

2- Blood.

What are the procedures that are used for taking each specimen?1- CSF by lumbar puncture (spinal tap):• Firstly, The patient must give the health care team permission to do the test.

• There are different ways to get a sample of CSF. Lumbar puncture, commonly called a spinal tap, is the most common method. The test is usually done like this:

• The patient lies on his or her side, with knees pulled up toward the chest, and chin tucked downward. Sometimes the test is done with the person sitting up, but bent forward.

• Holding the position is very important.•Why?•Holding the position may be uncomfortable, but it is extremely important to stay in this bent position to avoid moving the needle and possibly injuring the spinal cord.

CSF lumbar puncture position

CSF lumbar puncture position

CSF lumbar puncture position

•After the back is cleaned, the health care provider will inject a local numbing medicine (anesthetic) into the lower spine.

•A spinal needle is inserted, usually into the lower back area.

•Once the needle is properly positioned, CSF pressure is measured and a sample is collected.

•The needle is removed, the area is cleaned, and a bandage is placed over the needle site. The person is often asked to lie down for a short time after the test.

•Occasionally, special x-rays are used to help guide the needle into the proper position. This is called fluoroscopy.

• Alternative methods of CSF collection are rarely used, but may be necessary if the person has a back deformity or an infection:

• Cisternal puncture uses a needle placed below the occipital bone (back of the skull). It can be dangerous because it is so close to the brain stem. It is always done with fluoroscopy.

• Ventricular puncture is even more rare, but may be recommended in people with possible brain herniation. This test is usually done in the operating room. A hole is drilled in the skull, and a needle is inserted directly into one of brain's ventricles.

Turbid CSF Clear CSF

2- Blood by venepuncture:

•Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand.• The site is cleaned with germ-killing medicine (antiseptic). •The health care provider wraps an elastic band around the upper arm (Tourniquet) to apply pressure to the area and make the vein swell with blood.•Next, the health care provider gently inserts a needle into the vein.• The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.•Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

•In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects onto a slide or test strip. A bandage may be placed over the area if there is any bleeding

Blood venepuncture

Blood venepuncture

Blood sample

Blood sample

What are the investigations that you have to do to identify the pathogen?What do you find in each test?

1- Standard CSF bacterial culture:• CSF is placed in special dish (called a culture medium, chocolate agar in 5% CO2 atmosphere).• The laboratory personnel watch to see if bacteria grow in the dish. Growth means there is an infection.

video:Spinal fluid (CSF) is being cultured on to Chocolate agar and MacConkey's agar as a part of laboratory diagnosis of acute bacterial (pyogenic) meningitis.

PLAY

2- gram stained film of CSF smear :I will see intracellular gram negative kidney bean-shaped diplococci.

This micrograph depicts the presence of aerobic Gram-negative Neisseria meningitidis diplococcal bacteria.

3- CSF examination for cell count, glucose, and protein:

meningitis normal

Glucose (mg/dL):

Normal to marked decrease. <40 mg/dL.

40–85

Protein (mg/dL):

(Marked increase) > 250 15–45

WBCs (cells/µL)

>500 (usually > 1000). 0–5/µL (adults or children); up to 30/µL (newborns)

4- Blood :microscopically to look for the germ, and to check that the patient is otherwise healthy.

5- Oxidase , catalase and carbohydrate test :If oxidase and catalase positive meningococcus .If ferments the glucose and maltose meningococcus .

• oxidase ( cytochrome C oxidase ) test :- Rapid test .- Flood colony with phenylenediamine,in presence of oxidase , phenylenediamine turns black .

5- latex agglutination (or CIE- counter immunoelectrophorsis ):To identify N.meningitidis capsular antigens in CSF.

Recess

Resumptio

n

Final diagnosis• Meningococcal Meningitis

Treatments• Drugs: I. Penicillin II. ChloramphenicolIII. Cephalosporin

Prevention• Meningococcal vaccines protect against most of

the cases of meningococcal diseases but no all of the cases. The 2 types of vaccines available are : meningococcal polysaccharide vaccine (Menomune),and meningococcal conjugate vaccine( Menactra & Menveo).

Many thanks Muhammed Shihab

Ali Anas

Mahgoub Omar