Section 2: special bacteriology

Species

Morphology and tinctorial properties

Culture medium, optimal conditions

Cultural properties

The main virulence factors

Tests for differentiation

Typing

S. pneumoniae

Gram-positive lancet-shaped diplococci, possess capsule

5% blood agar, 37^оС,

СО₂-incubator

Small colonies with greenish zones of α-hemolysis

• capsule

• IgA-protease

• Hyaluronidase

Sensitive to bile and optochin

Species is subdivided into serovars (>80) by capsular antigen

S. pyogenes

Gram-positive cocci in short or long chains

5% blood agar, 37^оС,

СО₂-incubator

Small colonies with clear zones of

β-hemolysis

• М-protein

• Hyaluronidase

• O-streprokinase

• O-streptolysin

• Erythrogenic toxin*

Sensitive to bacitracin

Species is subdivided into serovars (by Lancefield classification) according M-protein structure

Species

Serogroup

Type of Hemolysis

Tests for differentiation

Anatomic site

Representative Disease

S. pyogenes

A

β- hemolysis

Sensitive to bacitracin

Skin, oropharynx

Pharyngitis, tonsillitis, pneumonia, sepsis, scalet fever, erysipelas, rheumatic fever, glomerulonephritis,

septic endocarditis

S. agalactiae

B

β- hemolysis

Resistant to bacitracin

Genital organs of woman

Neonatal meningitis and pneumonia, sepsis

Enterococcus faecalis

D

α – or β - hemolysis

Resistant to 6,5% NaCl; form black colonies on bile-esculin medium

Intestine, urethra, woman genitalia

Urinary tract infections, cholecystitis, endocarditis

S. pneumoniae

Not classified

α - hemolysis

Sensitive to bile and optochin

Upper respiratory tract, oropharynx

Pneumonia, otitis, sinusitis, sepsis

S. viridians, S. mitis,

S. mutans

Not classified

α - hemolysis

Resistant to bile and optochin

Oropharynx

Infectious endocarditis, caries

Examination day (step)

Manipulations

Results and conclusions

1

1. Preparing of serial 100-fold dilutions of sputum in sterile isotonic solution to obtain dilutions 10^-3,10^-5 a nd10^-7:

9.9 ml 9.9 ml 9.9 ml

2. Inoculation of 0,1 ml of sputum from 10^-5dilution onto the egg-yolk-salt agar and 5% blood agar; and 0,1 ml 10^-7 dilution of sputum on the 5% blood agar

2

1. Microscopic examination of colonies (Gram stain)

2. Subculture on the slant

3

1. . Microscopic examination of colonies obtained on the MPA slant and simple staining for checking the purity of culture

2. Inoculation of the rabbit’s citrate plasma (for determining the coagulase activity) and mannitol-containing Hiss' medium with the pure culture (in anaerobic conditions under immersion oil layer)

3. Phagotyping of staphylococci with

bacteriophages ________________

4. Determination of antibiotic susceptibility of the pure culture obtained (disk diffusion method)

• ______________- ___ mm ( )

• ______________- ___ mm ( )

• ______________- ___ mm ( )

• ______________- ___ mm ( )

• ______________- ___ mm ( )

CONCLUSION: the microbe isolated from sputum is identified as _____________ (phagotype: ____). It is isolated in the concentration of __________ CFU/ml that confirms/does not confirm its etiologic role in the development of symptoms of pneumonia. The isolated bacterium is sensitive to________________________________

and resistant to_________________________________________.