Gram positive cocci

Gram positive bacteria

1. Gram-positive cocci

2. Cocci is a designation for bacteria that have a round shape.

3. This group includes a large species diversity of microorganisms and combines various taxonomic units : staphylococci , streptococci , enterococci , tetracocci and others .

4. Staphylococcus

5. Staphylococci ( lat . Staphylococcus , from the Greek . στ αφυλή — "bunch of grapes" and Greek. κκκκος - " grain , berry ") is a genus of bacteria in the Staphylococcaceae family .

6. Staphylococci are facultative anaerobes , fixed gram-positive cocci whose cell diameter is from 0.6 to 1.2 microns .

7. Non-spore-forming cells are usually uncapsulated , but some species , such as Staphylococcus aureus , can form a capsule . Some staphylococci synthesize characteristic pigments .

8. Forms of colonies on dense nutrient media-rounded , convex , pigmented ( white , yellow , Golden ). On liquid — uniform turbidity .

9. Some types of staphylococci

10. Staphylococcus aureus ( Staphylococcus aureus ) is the most pathogenic for humans . Named for its ability to form a Golden pigment . It can cause purulent inflammatory processes in almost all organs and tissues .

11. Methicillin-resistant Staphylococcus aureus — any strain of Staphylococcus aureus that is resistant to a large group of antibiotics-beta-lactams ( including penicillins and cephalosporins ). Diseases caused by these strains are particularly difficult to treat .

12. Epidermal Staphylococcus ( Staphylococcus epidermidis ) - often occurs on the skin and mucous membranes of a person , can cause sepsis , endocarditis , conjunctivitis , purulent infection of wounds and purulent infections of the urinary tract .

13. Saprophytic Staphylococcus ( Staphylococcus saprophyticus ) - can cause acute cystitis and urethritis .

14. Hemolytic Staphylococcus ( Staphylococcus haemolyticus ) - can cause various purulent inflammatory processes on different organs ; sepsis and skin lesions , endocarditis ; urethral lesions and cystitis .

15. Diagnostics Cytobacteriological of smears stained by the gram stain , and inoculation of the enriched nutrient mediumThe diagnosis of staphylococcal infection is established after bacterioscopy of gram-stained smears and sowing of infected material on nutrient media .

16. Staphylococci have biochemical activity . They produce toxins that have a strong effect on organ and tissue systems . The complexity of prevention and treatment is due to the high resistance of the bacterium to antibiotics and environmental factors . Microorganisms are not afraid of sunlight , actively reproduce in the air , live in water and food , can be stored for six months in a frozen or dried state , do not die under the influence of alcohol , sodium chloride , hydrogen peroxide .

17. Streptococci

18. Streptococci ( lat . Streptococcus ; from the Greek . στρε πτός — "chain" and the Greek. κκκκος — " grain ") is a genus of globular or ovoid asporogenic ( non-spore-forming ) gram-positive chemoorganotrophic facultative anaerobic bacteria from the Streptococcaceae family .

19. They live in the respiratory and digestive tracts , especially in the mouth , nose , and large intestine .

20. Typical cells less than 1 micron in diameter , arranged in pairs or chains , are stationary , except for strains of group D. they Form a capsule , easily turn into an L- shape .

21. Nutritional needs are complex . Usually grow on media with the addition of blood , blood serum , ascitic fluid , carbohydrates . The temperature optimum is 37°, pH 7.2-7.4. On dense media , small flat grayish colonies are formed , on liquid media , they give a tiny parietal and bottom growth , on blood agar — alpha or betagemolysis zones .

22. Classification of streptococci

23. 1) Streptococcus pyogenes ( former name Streptococcus haemolyticus ) - beta-hemolytic streptococci of group A. the cell Diameter is 0.6-1 microns , many strains form a capsule . Capsule strains grow in the form of mucous colonies that turn to matte when standing ; capsule-free strains form shiny , glossy colonies . Do not grow at 10 and 45°, in broth with 6.5% sodium chloride , at a pH of 9.6; in milk with 0.1% methylene blue . Ferment glucose , lactose , sucrose , salicin , trehalose , do not ferment inulin , sorbitol , glycerin , sodium hippurate . Most strains produce streptolysins , streptokinase , streptodornase , some-erythrogenic toxin . They live in the human pharynx normally and can cause various diseases ;

24. 2) Streptococcus pneumoniae-combined into a group of pneumococcal infections . The pathogen is a cocci with an elongated pole , arranged in pairs or short chains , motionless , spores do not form , when living in the body form a capsule , chemoorganotrophs , facultative anaerobes . Parasite of the human respiratory tract . It occurs normally in various diseases . Causes acute pneumonia and bronchitis in children and adults ;

25. 3-4) Streptococcus faecalis , Streptococcus faecies — group D Streptococcus , which are usually combined into a group of enterococci , cause septic processes ;

26. 5-8) Streptococcus sanguis , Streptococcus salivarius , Streptococcus mitis , Streptococcus mutans-hemolytic and non-hemolytic streptococci of various serogroups that produce polysaccharides and take part in the formation of dental plaques , their etiological role in caries is assumed;9) Streptococcus lactis ( transferred to the genus Lactococcus ) - lactic acid Streptococcus , lactic acid bacteria .