Upper and Lower Respiratory Tract

Infection

Upper Respiratory Tract Infection

“Throat Swab”

Throat swap culture

• First step : Breath deeply.

• Second step: open mouth widely& push the tongue out& phonate “AAHHH”

• Third step:

insert the cotton swap through the mouth and rotate on the area of tonsil or both tonsil.

4th step: remove the cotton swap from the mouth, avoid touch the tongue, teeth…

5th step: transport the specimen to the lab as

soon (avoid dry)

6th step

take the swap under sterile condition, rotate it on the first quadrant of blood agar plate

7th step

# then do the streaking method by loop and stab it few times, then incubate at 37 c / 24 h.

# Search for hemolytic

ß hemolytic: Clear zone.

Streptolysin S

Streptolysin O (v. imp)

Streptococcus pyogenes

• Colonies of Streptococcus pyogenes on sheep blood agar.

• Notice: * Presence of b hemolysis around colonies

• * Enhanced hemolysis around stabbing sites

• * Sensitivity to bacitracin (Disk A)

Streptococcus pyogenes

• Pin point colony: (white or gray)

• Gram stain: G+ve, cocci, single chain.

• Catalase enzyme: differentiate between

Streptococcus –ve

Staphylococcus +ve

Streptococcus pyogenes

• Antibiotic susceptibility of S. pyogenes.

• Bacitracin Sensitive• Optochin Resistance

Haemophilus influenzae

• G-ve, blood lover, fastidious M.O. need:

• X factor heme extra & intracellular.

• V factor NAD intracellular.

• Best media Choclate

Haemophilus influenzae

• G-negative coccobacilli, typical of H. influenzae

• Grayish mucoid colonies of H. influenzae on

chocolate agar•  

Haemophilus influenzae

• Shows phenomena Satellitism: growth on blood agar near a line of Staphylococcus aureus.

Haemophilus influenzae

Lower Respiratory Tract Infections

• Sputum Examination:

• Sputum: Trachiobroncial secretions, visco-elastic (95% water and only 5% solids) as it comes out, it is contaminated by nasal and salivary secretions and normal bacterial flora of the oral cavity.

Specimen collection

• In case of Adult: • 1- mouth should be

pre-rinsedremove contaminants.

• 2- first morning specimen, Good specimen <10 epith and >25 WBCs.

In case of children

• Nasopharyngeal swab.• Cough Swab method.• 1- the child mouth is held

open by using tongue depressor.

• 2- Epiglottis is visualized and is touched with swab to induce cough.

• 3- Material expelled deposited on the swab and cultured in three different media.

• * Blood media.• * Chocolate.• * MacConcy.

Macroscopic Examination

• Consistency and Appearance.

normal sputum is clear and watery.

• Color of Sputum: • Normal color is clear

and colorless.in case of infections

Color of Sputum

yellow (indicates pus and epithelial cells)=pneumonic+

• Staphylococcus aureus.

Green (pseudomonas)== Otitis.

Red (blood) TB.

Microscopic Examination

• Mycobacterium tuberculosis

• Acid fast bacilli

Mycobacterium tuberculosis

• Culture on Lowenestein-Jensen media.

• Yellowish colony on green background

Streptococcus pneumoniae

• Lancet-shaped, • G-positive

diplococci, • typical of S.

pneumoniae

S. pneumoniae

hemolysis on 5% sheep blood agar,

• typical of S. pneumoniae. Sensitivity to optochin is also demonstrated

Klebsiella pneumoniae

• Colonies of Klebsiella

pneumoniae on MacConkey agar,

• showing lactose fermentation and mucoid appearance

K. pneumoniae:

• IMViC reaction of K. pneumoniae:

- - + +

Pseudomonas aeruginosa

• Greenish discoloration of media due to production of pyocyanin by Pseudomonas aeruginosa

Pseudomonas aeruginosa

• Results of oxidase test

Corynebacterium diphtheriae

• G+ve non motile, pleomorphic rod.

• Formation of pseudomembrane covering the mouth & pharynx.

• Can be severe and sometimes fatal disease.

Paragonimus westermani

• Adult worm in the lung.

• Hermaphrodite (both sex)

Paragonimus westermani

• Eggs in sputum : diagnostic stages.

Paragonimus westermani

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